@article{YenesewTwinomuhweziKiremireetal.2009, author = {Yenesew, Abiy and Twinomuhwezi, Hannington and Kiremire, Bernard T. and Mbugua, Martin N. and Gitu, Peter M. and Heydenreich, Matthias and Peter, Martin G.}, title = {8-Methoxyneorautenol and radical scavenging flavonoids from Erythrina abyssinica}, issn = {1011-3924}, year = {2009}, abstract = {A new pterocarpan (named 8-methoxyneorautenol) was isolated from the acetone ext. of the root bark of Erythrina abyssinica. In addn., the known isoflavonoid derivs. eryvarin L, erycristagallin and shinpterocarpin were identified for the first time from the roots of this plant. The structures were detd. on the basis of spectroscopic evidence. The new compd. showed selective antimicrobial activity against Trichophyton mentagrophytes. The acetone ext. of the root bark of E. abyssinica showed radical scavenging activity towards 2,2-diphenyl-1-picrylhydrazyl radical (DPPH). The pterocarpenes, 3-hydroxy-9-methoxy-10-(3,3-dimethylallyl)pterocarpene and erycristagallin, were the most active constituents of the roots of this plant and showing dose-dependent activities similar to that of the std. quercetin. [on SciFinder (R)]}, language = {en} } @article{HeintzWatsonJakobssonetal.2018, author = {Heintz, Kasper Elm and Watson, D. and Jakobsson, P. and Fynbo, J. P. U. and Bolmer, J. and Arabsalmani, M. and Cano, Zach and Covino, S. and Gomboc, A. and Japelj, J. and Kaper, L. and Krogager, J. -K. and Pugliese, G. and Sanchez-Ramirez, R. and Selsing, J. and Sparre, Martin and Tanvir, N. R. and Thone, C. C. and de Ugarte Postigo, A. and Vergani, S. D.}, title = {Highly ionized metals as probes of the circumburst gas in the natal regions of gamma-ray bursts}, series = {Monthly notices of the Royal Astronomical Society}, volume = {479}, journal = {Monthly notices of the Royal Astronomical Society}, number = {3}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {0035-8711}, doi = {10.1093/mnras/sty1447}, pages = {3456 -- 3476}, year = {2018}, abstract = {We present here a survey of high-ionization absorption lines in the afterglow spectra of long-duration gamma-ray bursts (GRBs) obtained with the VLT/X-shooter spectrograph. Our main goal is to investigate the circumburst medium in the natal regions of GRBs. Our primary focus is on the N vλλ 1238, 1242 line transitions, but we also discuss other high-ionization lines such as O vi, C iv, and Si iv. We find no correlation between the column density of N v and the neutral gas properties such as metallicity, H i column density, and dust depletion; however, the relative velocity of N v, typically a blueshift with respect to the neutral gas, is found to be correlated with the column density of H i. This may be explained if the N v gas is part of an H ii region hosting the GRB, where the region's expansion is confined by dense, neutral gas in the GRB's host galaxy. We find tentative evidence (at 2σ significance) that the X-ray derived column density, NH, X, may be correlated with the column density of N v, which would indicate that both measurements are sensitive to the column density of the gas located in the vicinity of the GRB. We investigate the scenario where N v (and also O vi) is produced by recombination after the corresponding atoms have been stripped entirely of their electrons by the initial prompt emission, in contrast to previous models where highly ionized gas is produced by photoionization from the GRB afterglow.}, language = {en} } @article{BergnerTrauth2004, author = {Bergner, Andreas G. N. and Trauth, Martin H.}, title = {Comparison of the hydrologic and hydrochemical evolution of Lake Naivasha (Kenya) during three highstands between 175 and 60 kyr BP}, year = {2004}, abstract = {Three diatomite beds exposed in the Ol Njorowa Gorge south of Lake Naivasha, Central Kenya Rift, document three major lake-level highstands between 175 and 60 kyr BP. Diatom transfer-function estimates of hydrological and hydrochemical parameters suggest that a deep and large freshwater lake existed during the highstands at 135 and 80 kyr BP. In contrast, a shallower but more expanded freshwater lake existed at 110 kyr BP. The best analog for the most extreme highstand at 135 kyr BP is the highstand during the Early Holocene humid period from 10 to 6 kyr BP. The environmental conditions as reconstructed from diatom assemblages suggest long-lasting episodes of increased humidity during the high lake periods. This contrasts to the modern situation with a relatively shallow Lake Naivasha characterized by rapid water level fluctuations within a few decades. The most likely cause for the variable hydrological conditions since 175 kyr BP is orbitally driven insolation changes on the equator and increased lateral moisture transport from the ocean.}, language = {en} } @article{KoenigAblerAgartzetal.2020, author = {Koenig, Julian and Abler, Birgit and Agartz, Ingrid and akerstedt, Torbjorn and Andreassen, Ole A. and Anthony, Mia and Baer, Karl-Juergen and Bertsch, Katja and Brown, Rebecca C. and Brunner, Romuald and Carnevali, Luca and Critchley, Hugo D. and Cullen, Kathryn R. and de Geus, Eco J. C. and de la Cruz, Feliberto and Dziobek, Isabel and Ferger, Marc D. and Fischer, Hakan and Flor, Herta and Gaebler, Michael and Gianaros, Peter J. and Giummarra, Melita J. and Greening, Steven G. and Guendelman, Simon and Heathers, James A. J. and Herpertz, Sabine C. and Hu, Mandy X. and Jentschke, Sebastian and Kaess, Michael and Kaufmann, Tobias and Klimes-Dougan, Bonnie and Koelsch, Stefan and Krauch, Marlene and Kumral, Deniz and Lamers, Femke and Lee, Tae-Ho and Lekander, Mats and Lin, Feng and Lotze, Martin and Makovac, Elena and Mancini, Matteo and Mancke, Falk and Mansson, Kristoffer N. T. and Manuck, Stephen B. and Mather, Mara and Meeten, Frances and Min, Jungwon and Mueller, Bryon and Muench, Vera and Nees, Frauke and Nga, Lin and Nilsonne, Gustav and Ordonez Acuna, Daniela and Osnes, Berge and Ottaviani, Cristina and Penninx, Brenda W. J. H. and Ponzio, Allison and Poudel, Govinda R. and Reinelt, Janis and Ren, Ping and Sakaki, Michiko and Schumann, Andy and Sorensen, Lin and Specht, Karsten and Straub, Joana and Tamm, Sandra and Thai, Michelle and Thayer, Julian F. and Ubani, Benjamin and van Der Mee, Denise J. and van Velzen, Laura S. and Ventura-Bort, Carlos and Villringer, Arno and Watson, David R. and Wei, Luqing and Wendt, Julia and Schreiner, Melinda Westlund and Westlye, Lars T. and Weymar, Mathias and Winkelmann, Tobias and Wu, Guo-Rong and Yoo, Hyun Joo and Quintana, Daniel S.}, title = {Cortical thickness and resting-state cardiac function across the lifespan}, series = {Psychophysiology : journal of the Society for Psychophysiological Research}, volume = {58}, journal = {Psychophysiology : journal of the Society for Psychophysiological Research}, number = {7}, publisher = {Wiley}, address = {Hoboken}, issn = {0048-5772}, doi = {10.1111/psyp.13688}, pages = {16}, year = {2020}, abstract = {Understanding the association between autonomic nervous system [ANS] function and brain morphology across the lifespan provides important insights into neurovisceral mechanisms underlying health and disease. Resting-state ANS activity, indexed by measures of heart rate [HR] and its variability [HRV] has been associated with brain morphology, particularly cortical thickness [CT]. While findings have been mixed regarding the anatomical distribution and direction of the associations, these inconsistencies may be due to sex and age differences in HR/HRV and CT. Previous studies have been limited by small sample sizes, which impede the assessment of sex differences and aging effects on the association between ANS function and CT. To overcome these limitations, 20 groups worldwide contributed data collected under similar protocols of CT assessment and HR/HRV recording to be pooled in a mega-analysis (N = 1,218 (50.5\% female), mean age 36.7 years (range: 12-87)). Findings suggest a decline in HRV as well as CT with increasing age. CT, particularly in the orbitofrontal cortex, explained additional variance in HRV, beyond the effects of aging. This pattern of results may suggest that the decline in HRV with increasing age is related to a decline in orbitofrontal CT. These effects were independent of sex and specific to HRV; with no significant association between CT and HR. Greater CT across the adult lifespan may be vital for the maintenance of healthy cardiac regulation via the ANS-or greater cardiac vagal activity as indirectly reflected in HRV may slow brain atrophy. Findings reveal an important association between CT and cardiac parasympathetic activity with implications for healthy aging and longevity that should be studied further in longitudinal research.}, language = {en} } @article{OliveiraelGueddariMoerschbacheretal.2008, author = {Oliveira, Enio N. and el Gueddari, Nour E. and Moerschbacher, Bruno M. and Peter, Martin G. and Franco, Telma T.}, title = {Growth of phytopathogenic fungi in the presence of partially acetylated chitooligosaccharides}, issn = {0301-486X}, year = {2008}, abstract = {Four phytopathogenic fungi were cultivated up to six days in media contg. chitooligosaccharide mixts. differing in av. DP and F A. The three different mixts. were named Q3 (which contained oligosaccharides of DP2-DP10, with DP2-DP7 as main components), Q2 (which contained oligosaccharides of DP2-DP12, with DP2-DP10 as main components) and Q1 (which derived from Q2 and contained oligomers of DP5-DP8 with hexamer and a heptamer as the main components). The novel aspect of this work is the description of the effect of mixts. of oligosaccharides with different and known compn. on fungal growth rates. The growth rate of Alternaria alternata and Rhizopus stolonifer was initially inhibited by Q3 and Q2 at higher concns. Q1 had a growth stimulating effect on these two fungi. Growth of Botrytis cinerea was inhibited by Q3 and Q2, while Q1 had no effect on the growth of this fungus. Growth of Penicillium expansum was only slightly inhibited by higher concns. of sample Q3, while Q2 and Q1 had no effect. The inhibition of growth rates or their resistance toward chitooligosaccharides correlated with the absence or presence of chitinolytic enzymes in the culture media, resp. [on SciFinder (R)]}, language = {en} } @article{IssareeVijayakrishnanAbdelnuretal.2009, author = {Issaree, Arisara and Vijayakrishnan, Balakumar and Abdelnur, Patricia V. and Corilo, Yuri E. and Riccio, Maria F. and Sanvido, Gustavo B. and Eberlin, Marcos N. and Peter, Martin G.}, title = {Mass spectrometry of aminoglucan oligosaccharides using electrospray ionization MS/MS and MS/MS/MS}, year = {2009}, language = {en} } @article{DuehnforthBergnerTrauth2008, author = {D{\"u}hnforth, Miriam and Bergner, Andreas G. N. and Trauth, Martin H.}, title = {Early Holocene water budget of the Nakuru-Elmenteita basin, Central Kenya Rift}, issn = {0921-2728}, doi = {10.1007/s10933-006-9003-z}, year = {2008}, language = {en} } @article{PereiraNascimentoMagalhaesetal.2014, author = {Pereira, Fernanda S. and Nascimento, Heliara D. L. and Magalhaes, Alvicler and Peter, Martin G. and Bataglion, Giovana Anceski and Eberlin, Marcos N. and Gonzalez, Eduardo R. P.}, title = {ESI(+)-MS and GC-MS study of the hydrolysis of N-azobenzyl derivatives of chitosan}, series = {Molecules}, volume = {19}, journal = {Molecules}, number = {11}, publisher = {MDPI}, address = {Basel}, issn = {1420-3049}, doi = {10.3390/molecules191117604}, pages = {17604 -- 17618}, year = {2014}, abstract = {New N-p-chloro-, N-p-bromo-, and N-p-nitrophenylazobenzylchitosan derivatives, as well as the corresponding azophenyl and azophenyl-p-sulfonic acids, were synthesized by coupling N-benzylvchitosan with aryl diazonium salts. The synthesized molecules were analyzed by UV-Vis, FT-IR, H-1-NMR and N-15-NMR spectroscopy. The capacity of copper chelation by these materials was studied by AAS. Chitosan and the derivatives were subjected to hydrolysis and the products were analyzed by ESI(+)-MS and GC-MS, confirming the formation of N-benzyl chitosan. Furthermore, the MS results indicate that a nucleophilic aromatic substitution (SnAr) reaction occurs under hydrolysis conditions, yielding chloroaniline from N-p-bromo-, and N-p-nitrophenylazo-benzylchitosan as well as bromoaniline from N-p-chloro-, and N-p-nitrophenylazobenzyl-chitosan.}, language = {en} } @article{VijayakrishnanIssareeCoriloetal.2011, author = {Vijayakrishnan, Balakumar and Issaree, Arisara and Corilo, Yuri E. and Ferreira, Christina Ramires and Eberlin, Marcos N. and Peter, Martin G.}, title = {MSn of the six isomers of (GlcN)(2)(GlcNAc)(2) aminoglucan tetrasaccharides (diacetylchitotetraoses) rules of fragmentation for the sodiated molecules and application to sequence analysis of hetero-chitooligosaccharides}, series = {Carbohydrate polymers : an international journal devoted to scientific and technological aspects of industrially important polysaccharides}, volume = {84}, journal = {Carbohydrate polymers : an international journal devoted to scientific and technological aspects of industrially important polysaccharides}, number = {2}, publisher = {Elsevier}, address = {Oxford}, issn = {0144-8617}, doi = {10.1016/j.carbpol.2010.04.041}, pages = {713 -- 726}, year = {2011}, abstract = {The six possible isomers of di-N-acetylchitotetraoses [AADD, ADDA, ADAD, DADA, DAAD, and DDAA, where D stands for 2-amino-2-deoxy-3-D-glucose (GlcN) and A for 2-acetamido-2-deoxy-beta-D-glucose (GlcNAc)] were analyzed by ESI(+)-MSn. Collision induced dissociation via MSn experiments were performed for the sodiated molecules of m/z 769 [M+Na](+) for each isomer, and fragments were generated mainly by glycosidic bond and cross-ring cleavages. Rules of fragmentation were then established. A reducing end D residue yields the (O.2)A(4) cross-ring [M-59+Na](+) fragment of m/z 710 as the most abundant, whereas isomers containing a reducing end A prefer to lose water to form the [M-18+Na](+) ion of m/z 751, as well as abundant (O.2)A(4) cross-ring [M-101+Na](+) fragments of m/z 668 and B-3 [M-221+Na](+) ions of m/z 548. MS3 of C- and Y-type ions shows analogous fragmentation behaviour that allows identification of the reducing end next-neighbour residue. Due to gas-phase anchimeric assistance, B-type cleavage between the glycosidic oxygen and the anomeric carbon atom is favoured when the glycon is an A residue. Relative ion abundances are generally in the order B >> C > Y, but may vary depending on the next neighbour towards the non-reducing end. These fragmentation rules were used for partial sequence analysis of hetero-chitooligosaccharides of the composition D(2)A(3), D(3)A(3), D(2)A(4), D(4)A(3), and D(3)A(4).}, language = {en} } @article{TrauthBergnerFoersteretal.2015, author = {Trauth, Martin H. and Bergner, Andreas G. N. and Foerster, Verena and Junginger, Annett and Maslin, Mark A. and Sch{\"a}bitz, Frank}, title = {Episodes of environmental stability versus instability in Late Cenozoic lake records of Eastern Africa}, series = {Journal of human evolution}, volume = {87}, journal = {Journal of human evolution}, publisher = {Elsevier}, address = {London}, issn = {0047-2484}, doi = {10.1016/j.jhevol.2015.03.011}, pages = {21 -- 31}, year = {2015}, abstract = {Episodes of environmental stability and instability may be equally important for African hominin speciation, dispersal, and cultural innovation. Three examples of a change from stable to unstable environmental conditions are presented on three different time scales: (1) the Mid Holocene (MH) wet dry transition in the Chew Bahir basin (Southern Ethiopian Rift; between 11 ka and 4 ka), (2) the MIS 5-4 transition in the Naivasha basin (Central Kenya Rift; between 160 ka and 50 ka), and (3) the Early Mid Pleistocene Transition (EMPT) in the Olorgesailie basin (Southern Kenya Rift; between 1.25 Ma and 0.4 Ma). A probabilistic age modeling technique is used to determine the timing of these transitions, taking into account possible abrupt changes in the sedimentation rate including episodes of no deposition (hiatuses). Interestingly, the stable-unstable conditions identified in the three records are always associated with an orbitally-induced decrease of insolation: the descending portion of the 800 kyr cycle during the EMPT, declining eccentricity after the 115 ka maximum at the MIS 5-4 transition, and after similar to 10 ka. This observation contributes to an evidence-based discussion of the possible mechanisms causing the switching between environmental stability and instability in Eastern Africa at three different orbital time scales (10,000 to 1,000,000 years) during the Cenozoic. This in turn may lead to great insights into the environmental changes occurring at the same time as hominin speciation, brain expansion, dispersal out of Africa, and cultural innovations and may provide key evidence to build new hypotheses regarding the causes of early human evolution. (C) 2015 Elsevier Ltd. All rights reserved.}, language = {en} }