Refine
Year of publication
- 2016 (2217) (remove)
Document Type
- Article (1341)
- Doctoral Thesis (322)
- Postprint (215)
- Monograph/Edited Volume (74)
- Other (73)
- Review (64)
- Part of a Book (59)
- Part of Periodical (17)
- Preprint (17)
- Master's Thesis (12)
Language
- English (1772)
- German (408)
- Russian (16)
- Spanish (11)
- French (6)
- Italian (2)
- Multiple languages (1)
- Portuguese (1)
Is part of the Bibliography
- yes (2217) (remove)
Keywords
- German (11)
- climate change (10)
- Germany (8)
- Magellanic Clouds (8)
- aggression (8)
- children (8)
- prosody (8)
- sentence processing (8)
- adolescents (7)
- prevalence (7)
Institute
- Institut für Biochemie und Biologie (291)
- Institut für Geowissenschaften (291)
- Institut für Physik und Astronomie (258)
- Institut für Chemie (213)
- Institut für Ernährungswissenschaft (84)
- Mathematisch-Naturwissenschaftliche Fakultät (79)
- Institut für Mathematik (71)
- Department Psychologie (70)
- Wirtschaftswissenschaften (61)
- Sozialwissenschaften (57)
In this study, the stable conformers of neutral anserine were searched by molecular dynamics simulations and energy minimization calculations using the MM2 force field. Thermochemical calculations at B3LYP/6-31G(d) level of theory followed these preliminary calculations. The results confirmed that neutral anserine has quite a flexible structure and many stable gauche and trans conformers at room temperature. Nevertheless, two are considerably more favourable in energy than the others and expected to dominate the gas-phase and matrix IR spectra of the molecule. The corresponding structural and vibrational spectral data for these two conformers of neutral anserine, whose relative stabilities were also examined by high-accuracy energy calculations carried out using G3MP2B3 method, and for the most stable conformer of anserine in zwitterion form were calculated at B3LYP/6-311++G(d,p) level of theory. The calculated harmonic force constants were refined using the Scaled Quantum Mechanical Force Field (SQM-FF) method and then used to produce the refined wavenumbers, potential energy distributions (PEDs) and IR and Raman intensities. These refined data together with the scaled harmonic wavenumbers obtained using another method, Dual Scale factors (DS), enabled us to correctly analyse the observed IR and Raman spectra of anserine and revealed the effects of conformation and zwitterionic tautomerism on its structural and vibrational spectral data. (C) 2016 Elsevier B.V. All rights reserved.
Background
Overweight and obesity are increasing health problems that are not restricted to adults only. Childhood obesity is associated with metabolic, psychological and musculoskeletal comorbidities. However, knowledge about the effect of obesity on the foot function across maturation is lacking. Decreased foot function with disproportional loading characteristics is expected for obese children. The aim of this study was to examine foot loading characteristics during gait of normal-weight, overweight and obese children aged 1-12 years.
Methods
A total of 10382 children aged one to twelve years were enrolled in the study. Finally, 7575 children (m/f: n = 3630/3945; 7.0 +/- 2.9yr; 1.23 +/- 0.19m; 26.6 +/- 10.6kg; BMI: 17.1 +/- 2.4kg/m(2)) were included for (complete case) data analysis. Children were categorized to normalweight (>= 3rd and <90th percentile; n = 6458), overweight (>= 90rd and <97th percentile; n = 746) or obese (>97th percentile; n = 371) according to the German reference system that is based on age and gender-specific body mass indices (BMI). Plantar pressure measurements were assessed during gait on an instrumented walkway. Contact area, arch index (AI), peak pressure (PP) and force time integral (FTI) were calculated for the total, fore-, mid-and hindfoot. Data was analyzed descriptively (mean +/- SD) followed by ANOVA/Welch-test (according to homogeneity of variances: yes/no) for group differences according to BMI categorization (normal-weight, overweight, obesity) and for each age group 1 to 12yrs (post-hoc Tukey Kramer/Dunnett's C; alpha = 0.05).
Results
Mean walking velocity was 0.95 +/- 0.25 m/s with no differences between normal-weight, overweight or obese children (p = 0.0841). Results show higher foot contact area, arch index, peak pressure and force time integral in overweight and obese children (p< 0.001). Obese children showed the 1.48-fold (1 year-old) to 3.49-fold (10 year-old) midfoot loading (FTI) compared to normal-weight.
Conclusion
Additional body mass leads to higher overall load, with disproportional impact on the midfoot area and longitudinal foot arch showing characteristic foot loading patterns. Already the feet of one and two year old children are significantly affected. Childhood overweight and obesity is not compensated by the musculoskeletal system. To avoid excessive foot loading with potential risk of discomfort or pain in childhood, prevention strategies should be developed and validated for children with a high body mass index and functional changes in the midfoot area. The presented plantar pressure values could additionally serve as reference data to identify suspicious foot loading patterns in children.
Neuromuscular response of the trunk to sudden gait disturbances: Forward vs. backward perturbation
(2016)
The study aimed to analyse neuromuscular activity of the trunk comparing four different perturbations during gait. Thirteen subjects (28 +/- 3 yrs) walked (1 m/s) on a split-belt treadmill, while 4 (belt) perturbations (F1, F2, B1, B2) were randomly applied. Perturbations differed, related to treadmill belt translation, in direction (forward (F)/backward (B)) and amplitude (20 m/s(2) (1)/40 m/s(2) (2)). Trunk muscle activity was assessed with a 12-lead-EMG. EMG-RMS [%] (0-200 ms after perturbation; normalized to RMS of normal gait) was analyzed for muscles and four trunk areas (ventral left/right; dorsal left/right). Ratio of ventral: dorsal muscles were calculated. Muscle onset [ms] was determined. Data analysis was conducted descriptively, followed by ANOVA (post hoc Tukey-Kramer (alpha = 0.05)). All perturbations lead to an increase in EMG-RMS (428 +/- 289%). F1 showed the lowest and F2 the highest increase for the flexors. B2 showed the highest increase for the extensors. Significant differences between perturbations could be observed for 6 muscles, as well as the 4 trunk areas. Ratio analysis revealed no significant differences (range 1.25 (B1) to 1.71 (F2) between stimuli. Muscle response time (ventral: 87.0 +/- 21.7 ms; dorsal: 88.4 +/- 17.0 ms) between stimuli was only significant (p = 0.005) for the dorsal muscles. Magnitude significantly influences neuromuscular trunk response patterns in healthy adults. Regardless of direction ventral muscles always revealed higher relative increase of activity while compensating the walking perturbations. (C) 2016 Elsevier Ltd. All rights reserved.
This study aimed to determine the relative and absolute reliability of ultrasound (US) measurements of the thickness and echogenicity of the plantar fascia (PF) at different measurement stations along its length using a standardized protocol. Twelve healthy subjects (24 feet) were enrolled. The PF was imaged in the longitudinal plane. Subjects were assessed twice to evaluate the intra-rater reliability. A quantitative evaluation of the thickness and echogenicity of the plantar fascia was performed using Image J, a digital image analysis and viewer software. A sonography evaluation of the thickness and echogenicity of the PF showed a high relative reliability with an Intra class correlation coefficient of 0.88 at all measurement stations. However, the measurement stations for both the PF thickness and echogenicity which showed the highest intraclass correlation coefficient (ICCs) did not have the highest absolute reliability. Compared to other measurement stations, measuring the PF thickness at 3 cm distal and the echogenicity at a region of interest 1 cm to 2 cm distal from its insertion at the medial calcaneal tubercle showed the highest absolute reliability with the least systematic bias and random error. Also, the reliability was higher using a mean of three measurements compared to one measurement. To reduce discrepancies in the interpretation of the thickness and echogenicity measurements of the PF, the absolute reliability of the different measurement stations should be considered in clinical practice and research rather than the relative reliability with the ICC.
Objective: To assess the intra-and inter-session reliability of estimates of motor unit behavior and muscle fiber properties derived from high-density surface electromyography (HDEMG). Methods: Ten healthy subjects performed submaximal isometric knee extensions during three recording sessions (separate days) at 10%, 30%, 50% and 70% of their maximum voluntary effort. The discharge timings of motor units of the vastus lateralis and medialis muscles were automatically identified from HDEMG by a decomposition algorithm. We characterized the number of detected motor units, their discharge rates, the coefficient of variation of their inter-spike intervals (CoVisi), the action potential conduction velocity and peak-to-peak amplitude. Reliability was assessed for each motor unit characteristics by intra-class correlation coefficient (ICC). Additionally, a pulse-to-noise ratio (PNR) was calculated, to verify the accuracy of the decomposition. Results: Good to excellent reliability within and between sessions was found for all motor unit characteristics at all force levels (ICCs > 0.8), with the exception of CoVisi that presented poor reliability (ICC < 0.6). PNR was high and similar for both muscles with values ranging between 45.1 and 47.6 dB (accuracy > 95%). Conclusion: Motor unit features can be assessed non-invasively and reliably within and across sessions over a wide range of force levels. Significance: These results suggest that it is possible to characterize motor units in longitudinal intervention studies. (C) 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.
Through the reactions of 1- or 2-naphthol and 4,5-dihydro-3H-benz[c]azepine or 6,7-dihydrothieno[3,2-c]pyridine, new aminonaphthol derivatives were prepared. The syntheses were extended by using N-containing naphthol analogues such as 5-hydroxyisoquinoline and 6-hydroxyquinoline. The ring closures of the novel bifunctional compounds were also achieved, resulting in new naphth[2,1-e][1,3]oxazines, naphth[1,2-e][1,3]oxazines, isoquinolino[5,6-e][1,3]oxazines and quinolino[5,6-e][1,3]oxazines. H-1 NMR spectra of the target heterocycles 16, 20 and 21 were sufficiently resolved to indentify the present stereochemistry; therefore, beside computed structures, spatial experimental (dipolar coupling-NOE) and computed (ring current effect of the naphthyl moiety-TSNMRS) NMR studies were employed. The studied heterocycles exist exclusively as S(14b),R(N), R(14b),S(N), and S(16b)S(N) isomers, respectively. The flexible moieties of the studied compounds prefer. (C) 2016 Elsevier Ltd. All rights reserved.
Information about the strength of donor-acceptor interactions in push-pull alkenes is valuable, as this so-called "push-pull effect' influences their chemical reactivity and dynamic behaviour. In this paper, we discuss the applicability of NMR spectral data and barriers to rotation around the CQC double bond to quantify the push-pull effect in biologically important 2-alkylidene-4-oxothiazolidines. While olefinic proton chemical shifts and differences in C-13 NMR chemical shifts of the two carbons constituting the CQC double bond fail to give the correct trend in the electron withdrawing ability of the substituents attached to the exocyclic carbon of the double bond, barriers to rotation prove to be a reliable quantity in providing information about the extent of donor-acceptor interactions in the push-pull systems studied. In particular all relevant kinetic data, that is the Arrhenius parameters ( apparent activation energy Ea and frequency factor A) and activation parameters ( Delta S-double dagger, Delta H-double dagger and Delta G(double dagger)), were determined from the data of the experimentally studied configurational isomerization of ( E)-9a. These results were compared to previously published related data for other two compounds, ( Z)-1b and ( 2E, 5Z)-7, showing that experimentally determined Delta G(double dagger) values are a good indicator of the strength of push-pull character. Theoretical calculations of the rotational barriers of eight selected derivatives excellently correlate with the calculated CQC bond lengths and corroborate the applicability of Delta G(double dagger) for estimation of the strength of the push-pull effect in these and related systems.
Background Overweight and obesity are increasing health problems that are not restricted to adults only. Childhood obesity is associated with metabolic, psychological and musculoskeletal comorbidities. However, knowledge about the effect of obesity on the foot function across maturation is lacking. Decreased foot function with disproportional loading characteristics is expected for obese children. The aim of this study was to examine foot loading characteristics during gait of normal-weight, overweight and obese children aged 1-12 years. Methods Results Mean walking velocity was 0.95 +/- 0.25 m/s with no differences between normal-weight, overweight or obese children (p = 0.0841). Results show higher foot contact area, arch index, peak pressure and force time integral in overweight and obese children (p< 0.001). Obese children showed the 1.48-fold (1 year-old) to 3.49-fold (10 year-old) midfoot loading (FTI) compared to normal-weight. Conclusion Additional body mass leads to higher overall load, with disproportional impact on the midfoot area and longitudinal foot arch showing characteristic foot loading patterns. Already the feet of one and two year old children are significantly affected. Childhood overweight and obesity is not compensated by the musculoskeletal system. To avoid excessive foot loading with potential risk of discomfort or pain in childhood, prevention strategies should be developed and validated for children with a high body mass index and functional changes in the midfoot area. The presented plantar pressure values could additionally serve as reference data to identify suspicious foot loading patterns in children.
Stumbling led to an increase in ROM, compared to unperturbed gait, in all segments and planes. These increases ranged between 107 +/- 26% (UTA/rotation) and 262 +/- 132% (UTS/lateral flexion), significant only in lateral flexion. EMG activity of the trunk was increased during stumbling (abdominal: 665 +/- 283%; back: 501 +/- 215%), without significant differences between muscles. Provoked stumbling leads to a measurable effect on the trunk, quantifiable by an increase in ROM and EMG activity, compared to normal walking. Greater abdominal muscle activity and ROM of lateral flexion may indicate a specific compensation pattern occurring during stumbling. (C) 2015 Elsevier Ltd. All rights reserved.
Background
Overweight and obesity are increasing health problems that are not restricted to adults only. Childhood obesity is associated with metabolic, psychological and musculoskeletal comorbidities. However, knowledge about the effect of obesity on the foot function across maturation is lacking. Decreased foot function with disproportional loading characteristics is expected for obese children. The aim of this study was to examine foot loading characteristics during gait of normal-weight, overweight and obese children aged 1-12 years.
Methods
A total of 10382 children aged one to twelve years were enrolled in the study. Finally, 7575 children (m/f: n = 3630/3945; 7.0 +/- 2.9yr; 1.23 +/- 0.19m; 26.6 +/- 10.6kg; BMI: 17.1 +/- 2.4kg/m(2)) were included for (complete case) data analysis. Children were categorized to normalweight (>= 3rd and <90th percentile; n = 6458), overweight (>= 90rd and <97th percentile; n = 746) or obese (>97th percentile; n = 371) according to the German reference system that is based on age and gender-specific body mass indices (BMI). Plantar pressure measurements were assessed during gait on an instrumented walkway. Contact area, arch index (AI), peak pressure (PP) and force time integral (FTI) were calculated for the total, fore-, mid-and hindfoot. Data was analyzed descriptively (mean +/- SD) followed by ANOVA/Welch-test (according to homogeneity of variances: yes/no) for group differences according to BMI categorization (normal-weight, overweight, obesity) and for each age group 1 to 12yrs (post-hoc Tukey Kramer/Dunnett's C; alpha = 0.05).
Results
Mean walking velocity was 0.95 +/- 0.25 m/s with no differences between normal-weight, overweight or obese children (p = 0.0841). Results show higher foot contact area, arch index, peak pressure and force time integral in overweight and obese children (p< 0.001). Obese children showed the 1.48-fold (1 year-old) to 3.49-fold (10 year-old) midfoot loading (FTI) compared to normal-weight.
Conclusion
Additional body mass leads to higher overall load, with disproportional impact on the midfoot area and longitudinal foot arch showing characteristic foot loading patterns. Already the feet of one and two year old children are significantly affected. Childhood overweight and obesity is not compensated by the musculoskeletal system. To avoid excessive foot loading with potential risk of discomfort or pain in childhood, prevention strategies should be developed and validated for children with a high body mass index and functional changes in the midfoot area. The presented plantar pressure values could additionally serve as reference data to identify suspicious foot loading patterns in children.
Mental disorders are among the greatest medical and social challenges facing us. They can occur at all stages of life and are among the most important commonly occurring diseases. In Germany 28 % of the population suffer from a mental disorder every year, while the lifetime risk of suffering from a mental disorder is almost 50 %. Mental disorders cause great suffering for those affected and their social network. Quantitatively speaking, they can be considered to be among those diseases creating the greatest burden for society due to reduced productivity, absence from work and premature retirement. The Federal Ministry of Education and Research is funding a new research network from 2015 to 2019 with up to 35 million euros to investigate mental disorders in order to devise and develop better therapeutic measures and strategies for this population by means of basic and translational clinical research. This is the result of a competitive call for research proposals entitled research network for mental diseases. It is a nationwide network of nine consortia with up to ten psychiatric and clinical psychology partner institutions from largely university-based research facilities for adults and/or children and adolescents. Furthermore, three cross-consortia platform projects will seek to identify shared causes of diseases and new diagnostic modalities for anxiety disorders, attention deficit hyperactivity disorders (ADHS), autism, bipolar disorders, depression, schizophrenia and psychotic disorders as well as substance-related and addictive disorders. The spectrum of therapeutic approaches to be examined ranges from innovative pharmacological and psychotherapeutic treatment to novel brain stimulation procedures. In light of the enormous burden such diseases represent for society as a whole, a sustainable improvement in the financial support for those researching mental disorders seems essential. This network aims to become a nucleus for long overdue and sustained support for a German center for mental disorders.
Watching the Vibration and Cooling of Ultrathin Gold Nanotriangles by Ultrafast X-ray Diffraction
(2016)
We study the vibrations of ultrathin gold nanotriangles upon optical excitation of the electron gas by ultrafast X-ray diffraction. We quantitatively measure the strain evolution in these highly asymmetric nano-objects, providing a direct estimation of the amplitude and phase of the excited vibrational motion. The maximal strain value is well reproduced by calculations addressing pump absorption by the nanotriangles and their resulting thermal expansion. The amplitude and phase of the out-of-plane vibration mode with 3.6 ps period dominating the observed oscillations are related to two distinct excitation mechanisms. Electronic and phonon pressures impose stresses with different time dependences. The nanosecond relaxation of the expansion yields a direct temperature sensing of the nano-object. The presence of a thin organic molecular layer at the nanotriangle/substrate interfaces drastically reduces the thermal conductance to the substrate.
As indicated by previous research, aging is associated with a decline in working memory (WM) functioning, related to alterations in fronto-parietal neural activations. At the same time, previous studies showed that WM training in older adults may improve the performance in the trained task (training effect), and more importantly, also in untrained WM tasks (transfer effects). However, neural correlates of these transfer effects that would improve understanding of its underlying mechanisms, have not been shown in older participants as yet. In this study, we investigated blood-oxygen-level-dependent (BOLD) signal changes during n-back performance and an untrained delayed recognition (Sternberg) task following 12 sessions (45 min each) of adaptive n-back training in older adults. The Sternberg task used in this study allowed to test for neural training effects independent of specific task affordances of the trained task and to separate maintenance from updating processes. Thirty-two healthy older participants (60-75 years) were assigned either to an n-back training or a no-contact control group. Before (t1) and after (t2) training/waiting period, both the n-back task and the Sternberg task were conducted while BOLD signal was measured using functional Magnetic Resonance Imaging (fMRI) in all participants. In addition, neuropsychological tests were performed outside the scanner. WM performance improved with training and behavioral transfer to tests measuring executive functions, processing speed, and fluid intelligence was found. In the training group, BOLD signal in the right lateral middle frontal gyrus/caudal superior frontal sulcus (Brodmann area, BA 6/8) decreased in both the trained n-back and the updating condition of the untrained Sternberg task at t2, compared to the control group. fMRI findings indicate a training-related increase in processing efficiency of WM networks, potentially related to the process of WM updating. Performance gains in untrained tasks suggest that transfer to other cognitive tasks remains possible in aging. (C) 2016 Elsevier Inc. All rights reserved.
Objective: To estimate the prevalence and type of antidepressant medication prescribed by German primary care physicians for patients with depression and osteoporosis. Methods: This study was a retrospective database analysis conducted in Germany utilizing the Disease Analyzer (R) Database (IMS Health, Germany). The study population included 3,488 female osteoporosis patients aged between 40 and 90 years recruited from 1,179 general practitioner practices and who were initially diagnosed with depression during the index period (January 2004 to December 2013). Follow-up lasted up to 12 months and was completed in August 2015. Also included in this study were 3,488 nonosteoporosis controls who were matched (1 : 1) to osteoporosis cases on the basis of age, health insurance coverage, severity of depression, and physician carrying out the diagnosis. Results: After 12 months of followup, 30.1% of osteoporosis and 29.9% of nonosteoporosis patients with mild depression (p = 0.783), 52.4% of osteoporosis and 48.0% of non-osteoporosis patients with moderate depression (p = 0.003), and 39.4% of osteoporosis and 35.1% of nonosteoporosis patients with severe depression (p = 0.147) were being treated with antidepressants. Osteoporosis patients with moderate depression had a higher chance of being prescribed antidepressant therapy at the initial diagnosis (hazard ratio (HR): 1.12, p = 0.014). No differences were found between osteoporosis and nonosteoporosis patients regarding the proportion of patients receiving selective serotonin reuptake inhibitors (SSRI)/serotonin-noradrenaline reuptake inhibitors (SNRI), tricyclic antidepressant (TCA), or other antidepressants. Osteoporosis patients were more often referred to hospitals or psychiatrists for consultation. Conclusion: Osteoporosis patients are more often treated initially with antidepressants than non-osteoporosis patients, especially within the groups of patients with moderate or severe depression. TCA was the most frequently used antidepressant therapy class on initial diagnosis in both patient groups. Osteo-porosis patients receive referrals to hospitals or psychiatrists more often than patients without osteoporosis.
Background: Despite extensive research in the past decades, the influence of genetics on cognitive functions in schizophrenia remains unclear. Dystrobrevin-binding protein 1 (DTNBP1) is one of the most promising candidate genes in schizophrenia. An association of DTNBP1 with cognitive dysfunction, particularly memory impairment, has been reported in a number of studies. However, the results remain inconsistent. The aim of this study was to measure the association between DTNBP1 polymorphisms and cognitive domains in a well-characterized sample. Methods: Ninety-one clinically stable schizophrenia outpatients underwent a battery of cognitive tests. Six single nucleotide polymorphisms (SNPs) of DTNBP1 were genotyped in all participants. Statistical and multivariate analyses were performed. Results: Factor analysis revealed 4 factors corresponding to distinct cognitive domains, namely sustained attention, set-shifting, executive functioning, and memory. We found a significant association of the rs909706 polymorphism with attention (p = 0.030) and a nonsignificant trend for set-shifting (p = 0.060). The other SNPs and haplotypes were not associated with cognitive function. Discussion: Replication of this finding in a larger sample is needed in order to confirm the importance of this particular polymorphism in the genetics of schizophrenia, particularly the distinct cognitive domains. In conclusion, the present study supports the involvement of DTNBP1 in the regulation of cognitive processes and demonstrates association in particular with sustained attention and set-shifting in schizophrenia patients. (C) 2016 S. Karger AG, Basel
The Summary Thirty-five thousand four hundred eighty-three female osteoporosis patients were compared with 35,483 patients without osteoporosis regarding the incidence of depression. The risk of depression is significantly increased for patients with osteoporosis compared with patients without osteoporosis in primary care practices within Germany. Introduction The objectives of the present study were to analyze the incidence of depression in German female patients with osteoporosis and to evaluate the risk factors for depression diagnosis within this patient population. Methods This study was a retrospective database analysis conducted in Germany utilizing the Disease Analyzer (R) Database (IMS Health, Germany). The study population included 70,966 patients between 40 and 80 years of age from 1072 primary care practices. The observation period was between 2004 and 2013. Follow-up duration was 5 years and was completed in April 2015. A total of 35,483 osteoporosis patients were selected after applying exclusion criteria, and 35,483 controls were chosen and then matched (1:1) to osteoporosis patients based on age, sex, health insurance coverage, depression diagnosis in the past, and follow-up duration after index date. The analyses of depression-free survival were carried out using Kaplan-Meier curves and log-rank tests. Cox proportional hazards models (dependent variable: depression) were used to adjust for confounders. Results Depression diagnoses were presented in 33.0% of the osteoporosis group and 22.7% of the control group after the 5-year follow-up (p < 0.001). Dementia, cancer, heart failure, coronary heart disease, and diabetes were associated with a higher risk of developing depression (p < 0.001). Private health insurance was associated with a lower risk of depression. There was no significant effect of fractures on depression risk. Conclusion The risk of depression is significantly increased for patients with osteoporosis in primary care practices within Germany.
AIM To determine the prevalence of depression and its risk factors among patients with coronary heart disease (CHD) treated in German primary care practices. METHODS Longitudinal data from nationwide general practices in Germany (n = 1072) were analyzed. Individuals initially diagnosed with CHD (2009-2013) were identified, and 59992 patients were included and matched (1: 1) to 59992 controls. The primary outcome measure was an initial diagnosis of depression within five years after the index date among patients with and without CHD. Cox proportional hazards models were used to adjust for confounders. RESULTS Mean age was equal to 68.0 years (SD = 11.3). A total of 55.9% of patients were men. After a five-year follow-up, 21.8% of the CHD group and 14.2% of the control group were diagnosed with depression (P < 0.001). In the multivariate regression model, CHD was a strong risk factor for developing depression (HR = 1.54, 95% CI: 1.49-1.59, P < 0.001). Prior depressive episodes, dementia, and eight other chronic conditions were associated with a higher risk of developing depression. Interestingly, older patients and women were also more likely to be diagnosed with depression compared with younger patients and men, respectively. CONCLUSION The risk of depression is significantly increased among patients with CHD compared with patients without CHD treated in primary care practices in Germany. CHD patients should be routinely screened for depression to ensure improved treatment and management.
Persistence with antidepressant drugs in patients with dementia: a retrospective database analysis
(2016)
Background: The aims of the present study are to determine what proportion of patients with dementia receives antidepressants, how long the treatment is administered, and what factors increase the risk of discontinuation. Methods: The study was based on Disease Analyzer database and included 1,203 general practitioners (GP) and 209 neurologists/psychiatrists (NP). 12,281 patients with a diagnosis of dementia and an initial prescription of an antidepressant drug between January 2004 and December 2013 were included. The main outcome measure was antidepressant discontinuation rates within 6 months of the index date. Results: After 6 months of follow-up, 52.7% of dementia patients treated with antidepressants had stopped medication intake. There was a significantly decreased risk for treatment discontinuation for patients using selective serotonin reuptake inhibitors (SSRRIs) or serotonin and norepinephrine reuptake inhibitors (SSNRIs) compared to tricyclic antidepressants. There was a significantly increased risk of treatment discontinuation for older patients and patients treated in NP practice. Comorbidity of diabetes or history of stroke was associated with a decreased risk of treatment discontinuation. Conclusion: The study results show insufficient persistence in antidepressant treatment in dementia patients in a real world setting. The improvement must be achieved to ensure the treatment recommended in the guidelines.
Background: Dementia is a psychiatric condition the development of which is associated with numerous aspects of life. Our aim was to estimate dementia risk factors in German primary care patients.
Methods: The case-control study included primary care patients (70-90 years) with first diagnosis of dementia (all-cause) during the index period (01/2010-12/2014) (Disease Analyzer, Germany), and controls without dementia matched (1:1) to cases on the basis of age, sex, type of health insurance, and physician. Practice visit records were used to verify that there had been 10 years of continuous follow-up prior to the index date. Multivariate logistic regression models were fitted with dementia as a dependent variable and the potential predictors.
Conclusions: Risk factors for dementia found in this study are consistent with the literature. Nevertheless, the associations between statin, PPI and antihypertensive drug use, and decreased risk of dementia need further investigations.
We present a temperature and fluence dependent Ultrafast X-Ray Diffraction study of a laser-heated antiferromagnetic dysprosium thin film. The loss of antiferromagnetic order is evidenced by a pronounced lattice contraction. We devise a method to determine the energy flow between the phonon and spin system from calibrated Bragg peak positions in thermal equilibrium. Reestablishing the magnetic order is much slower than the cooling of the lattice, especially around the Neel temperature. Despite the pronounced magnetostriction, the transfer of energy from the spin system to the phonons in Dy is slow after the spin-order is lost. (C) 2016 Author(s).
Prevention of Cognitive Decline: A Physical Exercise Perspective on Brain Health in the Long Run
(2016)
Behavioral choice can be characterized along two axes. One axis distinguishes reflexive, model-free systems that slowly accumulate values through experience and a model-based system that uses knowledge to reason prospectively. The second axis distinguishes Pavlovian valuation of stimuli from instrumental valuation of actions or stimulus–action pairs. This results in four values and many possible interactions between them, with important consequences for accounts of individual variation. We here explored whether individual variation along one axis was related to individual variation along the other. Specifically, we asked whether individuals' balance between model-based and model-free learning was related to their tendency to show Pavlovian interferences with instrumental decisions. In two independent samples with a total of 243 participants, Pavlovian–instrumental transfer effects were negatively correlated with the strength of model-based reasoning in a two-step task. This suggests a potential common underlying substrate predisposing individuals to both have strong Pavlovian interference and be less model-based and provides a framework within which to interpret the observation of both effects in addiction.
Datenbankbasierte epidemiologische Untersuchung über die Versorgung demenzerkrankter Patienten
(2016)
Hintergrund:
Demenz wird von der Weltgesundheitsorganisation als ein in der Regel chronisch oder progressiv verlaufendes Syndrom definiert, das von einer Vielzahl von Hirnerkrankungen verursacht wird, welche das Gedächtnis, das Denkvermögen, das Verhalten und die Fähigkeit, alltägliche Tätigkeiten auszuführen, beeinflussen. Weltweit leiden 47,5 Millionen Menschen unter Demenz und diese Zahl wird sich voraussichtlich bis zum Jahr 2050 verdreifachen.
In den vorliegenden Studien wurden zum Einem die Faktoren, welche mit dem Risiko einhergehen eine Demenz zu entwickeln, analysiert. Zum Anderen wurde die Persistenz der medikamentösen Behandlung von depressiven Zuständen mit Antidepressiva sowie die Persistenz der medikamentösen Behandlung von Verhaltensstörungen, therapiert mit Antipsychotika, bei Demenzpatienten untersucht.
Durchführung:
Alle drei Studien basieren auf den Daten der IMS Disease Analyzer-Datenbank.
Die Daten der Disease Analyzer-Datenbank werden über standardisierte Schnittstellen direkt monatlich aus dem Praxiscomputer generiert. Die Daten werden vor der Übertragung verschlüsselt und entsprechen in Umfang und Detaillierungsgrad der Patientenakte.
Risikofaktoren für eine Demenzdiagnose
Methode:
Insgesamt wurden in die Studie 11.956 Patienten mit einer Erstdiagnose (Indexdatum) einer Demenz (ICD 10: F01, F03, G30) zwischen Januar 2010 und Dezember 2014 eingeschlossen. 11.956 Kontrollpatienten (ohne Demenz) wurden den Patienten nach Alter, Geschlecht, Art der Krankenversicherung und Arzt zugeordnet. In beiden Fällen wurden die Praxisaufzeichnungen dazu verwendet, sicherzustellen, dass die Patienten vor dem Indexdatum jeweils 10 Jahre kontinuierlich beobachtet worden waren. Insgesamt wurden 23.912 Personen betrachtet.
Mehrere Erkrankungen, die möglicherweise mit Demenz assoziiert sind, wurden anhand von allgemeinärztlichen Diagnosen bestimmt (ICD-10-Codes): Diabetes (E10-E14), Hypertonie (I10), Adipositas (E66), Hyperlipidämie (E78), Schlaganfall (einschließlich transitorische ischämische Attacke, TIA) (I63, I64, G45), Parkinson-Krankheit (G20, G21), intrakranielle Verletzung (S06), koronare Herzkrankheit (I20-I25), leichte kognitive Beeinträchtigung (F06) und psychische und Verhaltensstörungen durch Alkohol (F10). Das Vorhandensein mehrerer Medikamente, wie z. B. Statine, Protonenpumpenhemmer und Antihypertensiva (einschließlich Diuretika, Beta-Blocker, Calciumkanalblocker, ACE-Hemmer und Angiotensin-II), wurde ebenfalls bemessen.
Ergebnisse:
Das Durchschnittsalter für die 11.956 Demenzpatienten und die 11.956 der Kontrollkohorte war 80,4 (SD 5,3) Jahre. 39,0% der waren männlich. In dem multivariaten Regressionsmodell, wurden folgende Variablen mit einem erhöhten Risiko von Demenz in einem signifikanten Einfluß assoziiert: milde kognitive Beeinträchtigung (MCI) (OR: 2,12), psychische und Verhaltensstörungen durch Alkohol (1,96), Parkinson-Krankheit (PD) (1,89), Schlaganfall (1,68), intrakranielle Verletzung (1,30), Diabetes (1,17), Fettstoffwechselstörung (1,07), koronare Herzkrankheit (1,06). Der Einsatz von Antihypertensiva (0,96), Statinen (OR: 0,94) und Protonen-Pumpen-Inhibitoren (PPI) (0,93) wurden mit einem verringerten Risiko der Entwicklung von Demenz.
Schlussfolgerung:
Die gefundenen Risikofaktoren für Demenz stehen in Einklang mit der Literatur. Nichtsdestotrotz bedürfen die Zusammenhänge zwischen der Verwendung von Statinen, PPI und Antihypertensiva und einem verringerten Demenzrisiko weiterer Untersuchungen.
Persistenz der Behandlung mit Antidepressiva bei Patienten mit Demenz
Methode:
Patienten wurden ausgewählt, wenn bei ihnen im Zeitraum zwischen Januar 2004 und Dezember 2013 eine Demenzdiagnose (ICD 10: F01, F03, G30) und eine erste Verordnung eines trizyklischen Antidepressivums oder selektiven Serotonin-
Wiederaufnahmehemmers (SSRI) oder Serotonin-Noradrenalin-Wiederaufnahmehemmers (SSNRI) vorlagen. Ausgewählte Patienten wurden über einen Zeitraum von bis zu zwei Jahre nach dem Indexdatum beobachtet. Das letzte Nachbeobachtungsdatum eines Patienten war der 31. Dezember 2014. Insgesamt standen 12.281 Patienten für die Persistenzanalyse zur Verfügung. Der Hauptzielparameter war die Abbruchrate der Antidepressivabehandlung innerhalb von sechs Monaten nach dem Indexdatum. Behandlungsabbruch wurde definiert als ein Zeitraum von 90 Tagen ohne diese Therapie.
Als demographische Daten wurden Alter, Art der Krankenversicherung (privat oder gesetzlich), Art der Praxis (Neurologe oder Allgemeinmediziner) und Praxisregion (Ost- oder Westdeutschland) erhoben. Die folgenden Demenzdiagnosen wurden berücksichtigt: Alzheimer-Krankheit (G30), vaskuläre Demenz (F01) und nicht näher bezeichnete Demenz (F03). Darüber hinaus wurde der Charlson-Komorbiditäts-Index als allgemeiner Marker für Komorbidität verwendet. Darüber hinaus wurden die folgenden Diagnosen als Komorbiditäten in die Studie aufgenommen: Depression (ICD 10: F32-33), Delir (F05), Typ-2-Diabetes mellitus (E11, E14), Hypertonie (I10), koronare Herzkrankheit (I24, I25), Schlaganfall (I63, I64), Myokardinfarkt (I21-23) und Herzinsuffizienz (I50).
Ergebnisse:
Nach sechs Monaten Nachbeobachtung hatten 52,7 % (von 12,281 Demenzpatienten) der mit Antidepressiva behandelten Demenzpatienten die Medikamenteneinnahme abgebrochen. Die multivariaten Regressionsanalysen zeigten ein signifikant geringeres Risiko für einen Behandlungsabbruch bei mit SSRRI oder SSNRI behandelten Patienten verglichen mit Patienten, die trizyklische Antidepressiva einnahmen. Es zeigte sich ein signifikant geringeres Risiko eines Behandlungsabbruchs bei jüngeren Patienten.
Schlussfolgerung:
Die Ergebnisse zeigen eine unzureichende Persistenz mit Antipsychotika bei Demenzpatienten unter Alltagsbedingungen. Es muss eine Verbesserung erreicht werden, um die in den Richtlinien empfohlene Behandlung sicherzustellen.
Persistenz der Behandlung mit Antipsychotika bei Patienten mit Demenz
Methode:
Diese Studie umfasste Patienten im Alter ab 60 Jahren mit Demenz beliebigen Ursprungs, die zwischen Januar 2009 und Dezember 2013 (Indexdatum) zum ersten Mal Antipsychotikaverordnungen (ATC: N05A) von deutschen Psychiatern erhielten. Der Nachbeobachtungszeitraum endete im Oktober 2015. Die Demenz wurde auf Grundlage der ICD-10-Codes für vaskuläre Demenz (F01), nicht näher bezeichnete Demenz (F03) und Alzheimer-Krankheit (G30) bewertet.
Der Hauptzielparameter war die Behandlungspersistenzrate über einen Zeitraum von mehr als 6 Monaten nach dem Indexdatum. Die Persistenz wurde als Therapiezeit ohne Absetzen der Behandlung, definiert als mindestens 180 Tage ohne Antipsychotikatherapie, geschätzt. Alle Patienten wurden für eine Dauer von bis zu zwei Jahren ab ihrem Indexdatum beobachtet.
Gleichzeitig auftretende Erkrankungen wurden anhand von Diagnosen (ICD-10-Codes) von Depression (F32, F33), Parkinson-Krankheit (G20), psychischer Störungen aufgrund bekannter physiologischer Erkrankungen (F06) und Persönlichkeits- und Verhaltensstörungen aufgrund physiologischer Erkrankungen (F07) bestimmt. Als demographische Daten wurden Alter, Geschlecht und Art der Krankenversicherung (privat/gesetzlich) erhoben.
Ergebnisse:
12,979 Demenzpatienten mit einem Durchschnittsalter von 82 Jahre (52.1% leben in Pflegeheimen) wurden in diese Studie analysiert. Nach zwei Jahren Nachbeobachtung hatten 54,8 %, 57,2 %, 61,1 % bzw. 65,4 % der Patienten zwischen 60-69, 70-79, 80-89 bzw. 90-99 Jahren Antipsychotikaverordnungen erhalten (p<0,001). 82,6 % der in Pflegeheimen lebenden Patienten und 76,2 % der Patienten in häuslicher Pflege setzten ihre Behandlung ebenfalls länger als 6 Monate fort; nach zwei Jahren lag der Anteil bei 63,9 % (in Pflegeheimen) bzw. 55,0 % (in häuslicher Pflege) (p<0,001).
Schlussfolgerung:
Die Studie zeigt, dass der Anteil der mit Antipsychotika behandelten Demenzpatienten sehr hoch ist. Weitere Studien, einschließlich qualitativer Untersuchungen, sind nötig, um die Gründe für dieses Verschreibungsverhalten zu verstehen und zu erklären.
Background: The goal of this study was to estimate the prevalence of and risk factors for diagnosed depression in heart failure (HF) patients in German primary care practices. Methods: This study was a retrospective database analysis in Germany utilizing the Disease Analyzer (R) Database (IMS Health, Germany). The study population included 132,994 patients between 40 and 90 years of age from 1,072 primary care practices. The observation period was between 2004 and 2013. Follow-up lasted up to five years and ended in April 2015. A total of 66,497 HF patients were selected after applying exclusion criteria. The same number of 66,497 controls were chosen and were matched (1:1) to HF patients on the basis of age, sex, health insurance, depression diagnosis in the past, and follow-up duration after index date. Results: HF was a strong risk factor for diagnosed depression (p < 0.0001). A total of 10.5% of HF patients and 6.3% of matched controls developed depression after one year of follow-up (p < 0.001). Depression was documented in 28.9% of the HF group and 18.2% of the control group after the five-year follow-up (p < 0.001). Cancer, dementia, osteoporosis, stroke, and osteoarthritis were associated with a higher risk of developing depression. Male gender and private health insurance were associated with lower risk of depression. Conclusions: The risk of diagnosed depression is significantly increased in patients with HF compared to patients without HF in primary care practices in Germany.
Background: Given the well-established association between perceived stress and quality of life (QoL) in dementia patients and their partners, our goal was to identify whether relationship quality and dyadic coping would operate as mediators between perceived stress and QoL. Results: We found negative correlations between stress and QoL in both partners (QoL-AD: r = -0.62; p < 0.001; WHO-QOL Overall: r = -0.27; p = 0.02). Spousal caregivers had a significantly lower DCI total score than dementia patients (p < 0.001). Dyadic coping was a significant mediator of the relationship between stress and QoL in spousal caregivers (z = 0.28; p = 0.02), but not in dementia patients. Likewise, relationship quality significantly mediated the relationship between stress and QoL in caregivers only (z = -2.41; p = 0.02). Conclusions: This study identified dyadic coping as a mediator on the relationship between stress and QoL in (caregiving) partners of dementia patients. In patients, however, we found a direct negative effect of stress on QoL. The findings suggest the importance of stress reducing and dyadic interventions for dementia patients and their partners, respectively.
Background/Aims: To analyze the duration of treatment with antipsychotics in German dementia patients. Methods: This study included patients aged 60 years and over with dementia who received a first-time antipsychotic prescription by psychiatrists between 2009 and 2013. The main outcome measure was the treatment rate for more than 6 months following the index date. Results: A total of 12,979 patients with dementia (mean age 82 years, 52.1% living in nursing homes) were included. After 2 years of follow-up, 54.8%, 57.2%, 61.1%, and 65.4% of patients aged 60 - 69, 70 - 79, 80 - 89, and 90 - 99 years, respectively, received antipsychotic prescriptions. 63.9% of subjects living in nursing homes and 55.0% of subjects living at home also continued their treatment (p-value < 0.001). Conclusion: The percentage of dementia patients treated with anti psychotics is very high.
We present a temperature and fluence dependent Ultrafast X-Ray Diffraction study of a laser-heated antiferromagnetic dysprosium thin film. The loss of antiferromagnetic order is evidenced by a pronounced lattice contraction. We devise a method to determine the energy flow between the phonon and spin system from calibrated Bragg peak positions in thermal equilibrium. Reestablishing the magnetic order is much slower than the cooling of the lattice, especially around the Néel temperature. Despite the pronounced magnetostriction, the transfer of energy from the spin system to the phonons in Dy is slow after the spin-order is lost.
We present a nanostructured device that functions as photoacoustic hard x-ray switch. The device is triggered by femtosecond laser pulses and allows for temporal gating of hard x-rays on picosecond (ps) timescales. It may be used for pulse picking or even pulse shortening in 3rd generation synchrotron sources. Previous approaches mainly suffered from insufficient switching contrasts due to excitation-induced thermal distortions. We present a new approach where thermal distortions are spatially separated from the functional switching layers in the structure. Our measurements yield a switching contrast of 14, which is sufficient for efficient hard x-ray pulse shortening. The optimized structure also allows for utilizing the switch at high repetition rates of up to 208 kHz. Published by AIP Publishing.
Background: First rank symptoms (FRS) of schizophrenia have been used for decades for diagnostic purposes. In the new version of the DSM-5, the American Psychiatric Association (APA) has abolished any further reference to FRS of schizophrenia and treats them like any other "criterion A' symptom (e.g. any kind of hallucination or delusion) with regard to their diagnostic implication. The ICD-10 is currently under revision and may follow suit. In this review, we discuss central points of criticism that are directed against the continuous use of first rank symptoms (FRS) to diagnose schizophrenia.
Recent technological developments have increased the number of variables being monitored in lakes and reservoirs using automatic high frequency monitoring (AHFM). However, design of AHFM systems and posterior data handling and interpretation are currently being developed on a site-by-site and issue-by-issue basis with minimal standardization of protocols or knowledge sharing. As a result, many deployments become short-lived or underutilized, and many new scientific developments that are potentially useful for water management and environmental legislation remain underexplored. This Critical Review bridges scientific uses of AHFM with their applications by providing an overview of the current AHFM capabilities, together with examples of successful applications. We review the use of AHFM for maximizing the provision of ecosystem services supplied, by lakes and reservoirs (consumptive and non consumptive uses, food production, and recreation), and for reporting lake status in the EU Water Framework Directive. We also highlight critical issues to enhance the application of AHFM, and suggest the establishment of appropriate networks to facilitate knowledge sharing and technological transfer between potential users. Finally, we give advice on how modern sensor technology can successfully be applied on a larger scale to the management of lakes and reservoirs and maximize the ecosystem services they provide.
The National Center for Biotechnology Information [http://www.ncbi.nlm.nih. gov/guide/taxonomy/] database enlists more than 15,500 bacterial species. But this also includes a plethora of uncultured bacterial representations. Owing to their metabolism, they directly influence biogeochemical cycles, which underscores the the important status of bacteria on our planet. To study the function of a gene from an uncultured bacterium, we have undertaken a de novo gene synthesis approach. Actinobacteria of the acI-B subcluster are important but yet uncultured members of the bacterioplankton in temperate lakes of the northern hemisphere such as oligotrophic Lake Stechlin (NE Germany). This lake is relatively poor in phosphate (P) and harbors on average similar to 1.3 x 10(6) bacterial cells/ml, whereby Actinobacteria of the ac-I lineage can contribute to almost half of the entire bacterial community depending on seasonal variability. Single cell genome analysis of Actinobacterium SCGC AB141-P03, a member of the acI-B tribe in Lake Stechlin has revealed several phosphate-metabolizing genes. The genome of acI-B Actinobacteria indicates potential to degrade polyphosphate compound. To test for this genetic potential, we targeted the exoP-annotated gene potentially encoding polyphosphatase and synthesized it artificially to examine its biochemical role. Heterologous overexpression of the gene in Escherichia coli and protein purification revealed phosphatase activity. Comparative genome analysis suggested that homologs of this gene should be also present in other Actinobacteria of the acI lineages. This strategic retention of specialized genes in their genome provides a metabolic advantage over other members of the aquatic food web in a P-limited ecosystem.
Carbon and nutrient cycling in kettle hole sediments depending on hydrological dynamics: a review
(2016)
Kettle holes as a specific group of isolated, small lentic freshwater systems (LFS) often are (i) hot spots of biogeochemical cycling and (ii) exposed to frequent sediment desiccation and rewetting. Their ecological functioning is greatly determined by immanent carbon and nutrient transformations. The objective of this review is to elucidate effects of a changing hydrological regime (i.e., dry-wet cycles) on carbon and nutrient cycling in kettle hole sediments. Generally, dry-wet cycles have the potential to increase C and N losses as well as P availability. However, their duration and frequency are important controlling factors regarding direction and intensity of biogeochemical and microbiological responses. To evaluate drought impacts on sediment carbon and nutrient cycling in detail requires the context of the LFS hydrological history. For example, frequent drought events induce physiological adaptation of exposed microbial communities and thus flatten metabolic responses, whereas rare events provoke unbalanced, strong microbial responses. Different potential of microbial resilience to drought stress can irretrievably change microbial communities and functional guilds, gearing cascades of functional responses. Hence, dry-wet events can shift the biogeochemical cycling of organic matter and nutrients to a new equilibrium, thus affecting the dynamic balance between carbon burial and mineralization in kettle holes.
In freshwater sciences, nitrogen gained increasing attention in the past as an important resource potentially influencing phytoplankton growth and thus eutrophication. Most studies and all management approaches, however, are still restricted to dissolved inorganic nitrogen (DIN = nitrate + nitrite + ammonium) since dissolved organic nitrogen (DON) was considered to be refractory for most of the photoautotrophs. In the meantime this assumption has been disproved for all aquatic systems. While research on DON in marine ecosystems substantially increased, in freshwater a surprisingly small number of investigations has been carried out on DON utilization by phytoplankton or even the occurrence and seasonal development of total DON or its compounds in lakes. Therefore, our present knowledge on DON utilization by phytoplankton is often based on single species experiments using a sole, usually low molecular weight DON component, often in unnaturally high amounts mainly carried out with marine phytoplankton species. Thus, we know that some phytoplankton species can take up different DON fractions if they are available in high concentrations and as sole nitrogen source. This does not necessarily imply that phytoplankton would perform likewise in natural environments. In addition, it will be difficult to draw conclusions on the behavior of freshwater phytoplankton from experiments with marine phytoplankton since the nutrient regime in marine environments differs from that of freshwater. In the light of the parallel availability of inorganic and organic nitrogen species in natural freshwater ecosystems, several questions must be raised: "If inorganic nitrogen is available, would phytoplankton really rely on an organic nitrogen source? Could a connection be detected between the seasonal development of DON and changes in the phytoplankton community composition as found for inorganic nitrogen? And if we reduce the input of inorganic nitrogen in lakes and rivers would the importance of DON as nitrogen source for phytoplankton increase, counteracting all management efforts or even leading to undesired effects due to changes in phytoplankton physiology and biodiversity?" I experimentally addressed the questions whether those DON compounds differentially influence growth, physiology and composition of phytoplankton both as sole available nitrogen source and in combination with other nitrogen compounds. I hypothesized that all offered DON - compounds (urea, natural organic matter (NOM), dissolved free and combined amino acids (DFAA, DCAA)) could be utilized by phytoplankton at natural concentrations. However, I assumed that the availability would decrease with increasing compound complexity. I furthermore hypothesized that the occurrence of low DIN concentrations would not affect the utilization of DON negatively. The nitrogen source, whatsoever, would have an impact on phytoplankton physiology as well as community composition. To investigate these questions and assumptions I conducted bioassays with algae monocultures as well as phytoplankton communities testing the utilization of various DON compounds by several freshwater phytoplankton species. Especially the potential utilization of NOM, a complex DON compound mainly consisting of humic substances is of interest, since it is usually regarded to be refractory. In order to be able to use natural concentrations of DON - compounds for my experiments the concentration of total DON and some DON - compounds (urea, humic substances, heigh molecular weight substances) was assessed in Lake Müggelsee. All compounds were able to support algae growth in the low natural concentrations supplied. However, I found that the offered DON compounds differ in their availability to various algae species, both, as sole nitrogen source or in combination with low DIN concentrations. As expected, the availability decreased with increasing complexity of the nitrogen compound. Furthermore, I could show that changes in algal physiology (nitrogen storage, metabolism) occur depending on the utilized nitrogen source. Especially the secondary photosynthetic pigment composition, heterocyst frequency and C:N - ratio of the algae were affected. The uptake and usage of certain nitrogen compounds might be more costly, potentially resulting in those physiology changes. Whereas laboratory experiments with single species revealed strong effects of DON, algal responses to DON in a multi-species situation remain unclear. Experiments with phytoplankton communities from Lake Müggelsee revealed that the nitrogen pool composition does influence the phytoplankton community structure. The findings furthermore show that several species combined might utilize the supplied nitrogen completely different than monocultures in the laboratory. Thus, besides the actual ability of algae to use the offered nitrogen sources other factors, such as interspecific competition, may be of importance. I further investigated, if the results of the laboratory experiments, can be verified in the field. Here, I surveyed the seasonal development of several dissolved organic matter (DOM) components (urea, high molecular weight substances (HMWS), humic substances (HS)) and associated parameters (Specific UV-absorption (SUVA), C:N - ratio) in Lake Müggelsee between 2011 and 2013. Furthermore, data from the long term measurements series of Lake Müggelsee such as physical (temperature, light, pH, O2) and chemical parameters (nitrogen, phosphorous, silica, inorganic carbon), zooplankton and phytoplankton data were used to investigate how much of the variability of the phytoplankton composition in Lake Müggelsee can be explained by DON/DOM concentration and composition, relative to the other groups of explanatory variables. The results show that DON mainly consists of rather complex compounds such as humic substances and biopolymers (80 %) and that only slight seasonal trends are detectable. Using variance partitioning I could show, that the usually investigated nutrients (DIN, silica, inorganic carbon, phosphorous) and abiotic factors together explain most of the algae composition as was to be expected (57.1 % of modeled variance). However, DOM and the associated parameters uniquely explain 10.3 % of the variance and thus slightly more than zooplankton with 9.3 %. I could therefore prove, that the composition of DOM (nitrogen and carbon) is connected to the algae composition in an eutrophic lake such as Lake Müggelsee. DON - compounds such as urea, however, could not be correlated with the occurrence of specific phytoplankton species. Overall, the results of this study imply that DON can be a valuable nitrogen source for freshwater phytoplankton. DON is used by various species even when DIN is available in low concentrations. Through the reduction of DIN in lakes and rivers, the DON:DIN ratio might be changed, resulting even in an increased importance of DON as phytoplankton nitrogen source. My work suggests that not only N2-fixation but also DON utilization might compensate for reduced N - input. Changes from DIN to DON as main nitrogen source might also promote certain, potentially undesired algae species and influence the biodiversity of a limnic ecosystem through changes in the phytoplankton community structure. Thus, DON, especially urea, should be included in calculations concerning total available nitrogen and when determining nitrogen threshold values. Furthermore, the input-reduction of DON, for example from waste-water treatment plants should also be evaluated and the results of my thesis should find consideration when planning to reduce the nitrogen input in freshwater.
About a quarter of anthropogenic CO2 emissions are currently taken up by the oceans, decreasing seawater pH. We performed a mesocosm experiment in the Baltic Sea in order to investigate the consequences of increasing CO2 levels on pelagic carbon fluxes. A gradient of different CO2 scenarios, ranging from ambient (similar to 370 mu atm) to high (similar to 1200 mu atm), were set up in mesocosm bags (similar to 55m(3)). We determined standing stocks and temporal changes of total particulate carbon (TPC), dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), and particulate organic carbon (POC) of specific plankton groups. We also measured carbon flux via CO2 exchange with the atmosphere and sedimentation (export), and biological rate measurements of primary production, bacterial production, and total respiration. The experiment lasted for 44 days and was divided into three different phases (I: t0-t16; II: t17-t30; III: t31-t43). Pools of TPC, DOC, and DIC were approximately 420, 7200, and 25 200 mmol Cm-2 at the start of the experiment, and the initial CO2 additions increased the DIC pool by similar to 7% in the highest CO2 treatment. Overall, there was a decrease in TPC and increase of DOC over the course of the experiment. The decrease in TPC was lower, and increase in DOC higher, in treatments with added CO2. During phase I the estimated gross primary production (GPP) was similar to 100 mmol C m(-2) day(-1), from which 75-95% was respired, similar to 1% ended up in the TPC (including export), and 5-25% was added to the DOC pool. During phase II, the respiration loss increased to similar to 100% of GPP at the ambient CO2 concentration, whereas respiration was lower (85-95% of GPP) in the highest CO2 treatment. Bacterial production was similar to 30% lower, on average, at the highest CO2 concentration than in the controls during phases II and III. This resulted in a higher accumulation of DOC and lower reduction in the TPC pool in the elevated CO2 treatments at the end of phase II extending throughout phase III. The "extra" organic carbon at high CO2 remained fixed in an increasing biomass of small-sized plankton and in the DOC pool, and did not transfer into large, sinking aggregates. Our results revealed a clear effect of increasing CO2 on the carbon budget and mineralization, in particular under nutrient limited conditions. Lower carbon loss processes (respiration and bacterial remineralization) at elevated CO2 levels resulted in higher TPC and DOC pools than ambient CO2 concentration. These results highlight the importance of addressing not only net changes in carbon standing stocks but also carbon fluxes and budgets to better disentangle the effects of ocean acidification.
Landscapes can be viewed as spatially heterogeneous areas encompassing terrestrial and aquatic domains. To date, most landscape carbon (C) fluxes have been estimated by accounting for terrestrial ecosystems, while aquatic ecosystems have been largely neglected. However, a robust assessment of C fluxes on the landscape scale requires the estimation of fluxes within and between both landscape components. Here, we compiled data from the literature on C fluxes across the air–water interface from various landscape components. We simulated C emissions and uptake for five different scenarios which represent a gradient of increasing spatial heterogeneity within a temperate young moraine landscape: (I) a homogeneous landscape with only cropland and large lakes; (II) separation of the terrestrial domain into cropland and forest; (III) further separation into cropland, forest, and grassland; (IV) additional division of the aquatic area into large lakes and peatlands; and (V) further separation of the aquatic area into large lakes, peatlands, running waters, and small water bodies These simulations suggest that C fluxes at the landscape scale might depend on spatial heterogeneity and landscape diversity, among other factors. When we consider spatial heterogeneity and diversity alone, small inland waters appear to play a pivotal and previously underestimated role in landscape greenhouse gas emissions that may be regarded as C hot spots. Approaches focusing on the landscape scale will also enable improved projections of ecosystems’ responses to perturbations, e.g., due to global change and anthropogenic activities, and evaluations of the specific role individual landscape components play in regional C fluxes. WIREs Water 2016, 3:601–617. doi: 10.1002/wat2.1147
The central rift of the Red Sea has 25 brine pools with different physical and geochemical characteristics. Atlantis II (ATIID), Discovery Deeps (DD) and Chain Deep (CD) are characterized by high salinity, temperature and metal content. Several studies reported microbial communities in these brine pools, but few studies addressed the brine pool sediments. Therefore, sediment cores were collected from ATIID, DD, CD brine pools and an adjacent brine-influenced site. Sixteen different lithologic sediment sections were subjected to shotgun DNA pyrosequencing to generate 1.47 billion base pairs (1.47 x 10(9) bp). We generated sediment-specific reads and attempted to annotate all reads. We report the phylogenetic and biochemical uniqueness of the deepest ATIID sulfur-rich brine pool sediments. In contrary to all other sediment sections, bacteria dominate the deepest ATIID sulfur-rich brine pool sediments. This decrease in virus-to-bacteria ratio in selected sections and depth coincided with an overrepresentation of mobile genetic elements. Skewing in the composition of viruses-to-mobile genetic elements may uniquely contribute to the distinct microbial consortium in sediments in proximity to hydrothermally active vents of the Red Sea and possibly in their surroundings, through differential horizontal gene transfer.
Aerobic Anoxygenic Phototrophic (AAP) bacteria are bacteriochlorophyll (BChl) a -containing organisms which use light energy to supplement their predominantly heterotrophic metabolism. Here, we investigated mortality and growth rates of AAP bacteria in three different freshwater lakes in Central Europe: the mountain lake Plesne, the oligo-mesotrophic Lake Stechlin and the forest pond Huntov. The mortality of AAP bacteria was estimated from diel changes of BChl a fluorescence. Net and gross growth rates were calculated from the increases in AAP cell numbers. The gross growth rates of AAP bacteria ranged from 0.38 to 5.6 d(-1), with the highest values observed during summer months. Simultaneously, the rapidly growing AAP cells have to cope with an intense grazing pressure by both zooplankton and protists. The presented results document that during the day, gross growth usually surpased mortality. Our results indicate that AAP bacteria utilize light energy under natural conditions to maintain rapid growth rates, which are balanced by a generally intense grazing pressure.
Active methane production in oxygenated lake waters challenges the long-standing paradigm that microbial methane production occurs only under anoxic conditions and forces us to rethink the ecology and environmental dynamics of this powerful greenhouse gas. Methane production in the upper oxic water layers places the methane source closer to the air water interface, where convective mixing and microbubble detrainment can lead to a methane efflux higher than that previously assumed. Microorganisms may produce methane in oxic environments by being equipped with enzymes to counteract the effects of molecular oxygen during methanogenesis or using alternative pathways that do not involve oxygen-sensitive enzymes. As this process appears to be influenced by thermal stratification, water transparency, and primary production, changes in lake ecology due to climate change will alter methane formation in oxic water layers, with far-reaching consequences for methane flux and climate feedback.
The use of high-frequency sensors on profiling buoys to investigate physical, chemical, and biological processes in lakes is
increasing rapidly. Profiling buoys with automated winches and sensors that collect high-frequency chlorophyll fluorescence
(ChlF) profiles in 11 lakes in the Global Lake Ecological Observatory Network (GLEON) allowed the study of the vertical
and temporal distribution of ChlF, including the formation of subsurface chlorophyll maxima (SSCM). The effectiveness of 3
methods for sampling phytoplankton distributions in lakes, including (1) manual profiles, (2) single-depth buoys, and (3)
profiling buoys were assessed. High-frequency ChlF surface data and profiles were compared to predictions from the
Plankton Ecology Group (PEG) model. The depth-integrated ChlF dynamics measured by the profiling buoy data revealed a
greater complexity that neither conventional sampling nor the generalized PEG model captured. Conventional sampling
techniques would have missed SSCM in 7 of 11 study lakes. Although surface-only ChlF data underestimated average water
column ChlF, at times by nearly 2-fold in 4 of the lakes, overall there was a remarkable similarity between surface and mean
water column data. Contrary to the PEG model’s proposed negligible role for physical control of phytoplankton during the
growing season, thermal structure and light availability were closely associated with ChlF seasonal depth distribution. Thus,
an extension of the PEG model is proposed, with a new conceptual framework that explicitly includes physical metrics to
better predict SSCM formation in lakes and highlight when profiling buoys are especially informative.
Marine habitats harbor a great diversity of microorganism from the three domains of life, only a small fraction of which can be cultivated. Metagenomic approaches are increasingly popular for addressing microbial diversity without culture, serving as sensitive and relatively unbiased methods for identifying and cataloging the diversity of nucleic acid sequences derived from organisms in environmental samples. Aerobic anoxygenic phototrophic bacteria (AAP) play important roles in carbon and energy cycling in aquatic systems. In oceans, those bacteria are widely distributed; however, their abundance and importance are still poorly understood. The aim of this study was to estimate abundance and diversity of AAPs in metagenomes from an upwelling affected coastal bay in Arraial do Cabo, Brazil, using in silico screening for the anoxygenic photosynthesis core genes. Metagenomes from the Global Ocean Sample Expedition (GOS) were screened for comparative purposes. AAPs were highly abundant in the free-living bacterial fraction from Arraial do Cabo: 23.88% of total bacterial cells, compared with 15% in the GOS dataset. Of the ten most AAP abundant samples from GOS, eight were collected close to the Equator where solar irradiation is high year-round. We were able to assign most retrieved sequences to phylo-groups, with a particularly high abundance of Roseobacter in Arraial do Cabo samples. The high abundance of AAP in this tropical bay may be related to the upwelling phenomenon and subsequent picoplankton bloom. These results suggest a link between upwelling and light abundance and demonstrate AAP even in oligotrophic tropical and subtropical environments. Longitudinal studies in the Arraial do Cabo region are warranted to understand the dynamics of AAP at different locations and seasons, and the ecological role of these unique bacteria for biogeochemical and energy cycling in the ocean.
The importance of ciliates as herbivores and in biogeochemical cycles is increasingly recognized. An opportunity to observe the potential consequences of zooplankton dominated by ciliates arose when winter fish kills resulted in strong suppression of crustaceans by young planktivorous fish in two shallow lakes. On an annual average, ciliates made up 38-76% of the total zooplankton biomass in both lakes during two subsequent years. Consequently, ciliate biomass and their estimated grazing potential were extremely high compared with other lakes of various trophic states and depths. Grazing estimates based on abundance and size suggest that ciliates should have cleared the water column of small (<5 mu m) and intermediate (5-50 mu m) sized phytoplankton more than once a day. Especially, small feeders within the ciliates were important, likely exerting a strong top-down control on small phytoplankton. Particle-attached bacteria were presumably strongly suppressed by intermediate-sized ciliate feeders. In contrast to other lakes, large phytoplankton was proportionately very abundant. The phytoplankton community had a high evenness, which may be attributed to the feeding by numerous fast growing and selective ciliate species. Our study highlights ciliates as an important trophic link and adds to the growing awareness of the role of winter processes for plankton dynamics.
Our knowledge of zoosporic fungal phylogeny, physiology, and ecological functions, in particular their role in aquatic food web dynamics and biogeochemistry, is limited. The recent discovery of numerous dark matter fungi (DMF), i.e., uncultured and poorly known taxa belonging to early diverging branches of the fungal tree (namely the Rozellomycota and Chytridiomycota) calls for reconsideration of the phylogeny and ecology of zoosporic fungi. In this opinion paper, we summarize the exploration of new, recently discovered lineages of DMF and their implications for the ecology, evolution, and biogeography of the rapidly growing fungal tree. We also discuss possible ecological roles of zoosporic fungi in relation to recent methodological developments including single cell genomics and cultivation efforts. Finally, we suggest linking explorative with experimental research to gain deeper insights into the physiology and ecological functioning of zoosporic fungi DMF in aquatic habitats. (C) 2015 Elsevier Ltd and The British Mycological Society. All rights reserved.
Latest data on the hydrophysical and biological state of the residual basins of the Aral Sea are presented and compared. Direct, quasi-simultaneous observations were carried out in the central part of the Western Large Aral Sea, the northern extremity of the Large Aral known as Chernyshev Bay, Lake Tshchebas, and the Small Aral Sea in October 2014. The Large Aral Sea and Lake Tshchebas transformed into hyperhaline water bodies with highly special taxocene structure. The Small Aral Sea was a relatively diverse brackish ecosystem, which was rather similar to the pre-desiccation environment. The Small Aral Sea and Lake Tshchebas exhibited a fully-mixed vertical structure, whereas the Western Large Aral Sea was strongly stratified. Our data show that during desiccation, different parts of the Aral Sea experienced different environmental conditions, resulting in qualitative and quantitative differences in the physical and biological regimes among the different residual basins.
Microcystins do not necessarily lower the sensitivity of Microcystis aeruginosa to tannic acid
(2016)
Different phytoplankton strains have been shown to possess varying sensitivities towards macrophyte allelochemicals, yet the reasons for this are largely unknown. To test whether microcystin (MC) is responsible for strain-specific sensitivities of Microcystis aeruginosa to macrophyte allelochemicals, we compared the sensitivity of 12 MC- and non-MC-producing M. aeruginosa strains, including an MC-deficient mutant and its wild type, to the polyphenolic allelochemical tannic acid (TA). Non-MC-producing strains showed a significantly higher sensitivity to TA than MC-producing strains, both in Chlorophyll a concentrations and quantum yields of photosystem II. In contrast, an MC-deficient mutant displayed a higher fitness against TA compared to its wild type. These results suggest that the resistance of M. aeruginosa to polyphenolic allelochemicals is not primarily related to MCs per se, but to other yet unknown protective mechanisms related to MCs.
Fungi constitute important and conspicuous components of aquatic microbial communities, but their diversity and functional roles remain poorly characterized. New methods and conceptual frameworks are required to accurately describe their ecological roles, involvement in global cycling processes, and utility for human activities, considering both cultivation independent techniques as well as experiments in laboratory and in natural ecosystems. Here we highlight recent developments and extant knowledge gaps in aquatic mycology, and provide a conceptual model to expose the importance of fungi in aquatic food webs and related biogeochemical processes.
Seit Jahrhunderten dienen die Körper der Frauen als Schlachtfelder. Doch erst vor 20 Jahren kam das Thema sexuelle Gewalt in bewaffneten Konflikten auf internationaler Ebene auf. Die Autorin untersucht den Beitrag der Vereinten Nationen zur Vorbeugung und Repression von sexueller Gewalt im Krieg. Ziel war es, eine Gesamtbestandaufnahme der ausgewählten Wege zum Schutz der Frauen vor sexueller Gewalt im Konflikt in den Bereichen 'Protection, Prevention und Prosecution' durchzuführen. Dies erfolgt anhand der Auswertung der Rechtsprechung des ICTY, ICTR, SCSL und des IStGH sowie der Durchführung der UN Action against sexual violence in conflict, der Arbeit der Human Rights Bodies und der afrikanischen Organisationen. Die Bekämpfung sexueller Gewalt im Krieg bleibt nach wie vor ein langwieriger Weg. Doch wo früher sachgerechte Normen gefehlt haben, wurden solide Grundlagen in den drei Bereichen geschaffen.