bluuebunny/crossref_metadata_2025_split huggingface dataset:
Controlling Peptide Self‐Assembly through a Native Chemical Ligation/Desulfurization Strategy
Authors: Rasale Dnyaneshwar B. , Konda Maruthi , Biswas Sagar , Das Apurba K. 
Published: January 2016

AbstractSelf‐assembled peptides were synthesized by using a native chemical ligation (NCL)/desulfurization strategy that maintained the chemical diversity of the self‐assembled peptides. Herein, we employed oxo‐ester‐mediated NCL reactions to incorporate cysteine, a cysteine‐based dipeptide, and a sterically hindered unnatural amino acid (penicillamine) into peptides. Self‐assembly of the peptides resulted in the formation of self‐supporting gels. Microscopy analysis indicated the formation of helical nanofibers, which were responsible for the formation of gel matrices. The self‐assembly of the ligated peptides was governed by covalent and non‐covalent interactions, as confirmed by FTIR, CD, fluorescence spectroscopy, and MS (ESI) analyses. Peptide disassembly was induced by desulfurization reactions with tris(2‐carboxyethyl)phosphine (TCEP) and glutathione at 80 °C. Desulfurization reactions of the ligated peptides converted the Cys and penicillamine functionalities into Ala and Val moieties, respectively. The self‐supporting gels showed significant shear‐thinning and thixotropic properties.
Direct conversion of xylan to butanol by a wild‐type Clostridium species strain G117
Authors: Yan Yu , Basu Anindya , Li Tinggang , He Jianzhong 
Published: January 2016

ABSTRACTLignocellulosic biomass has great potential for use as a carbon source for the production of second‐generation biofuels by solventogenic bacteria. Here we describe the production of butanol by a newly discovered wild‐type Clostridium species strain G117 with xylan as the sole carbon source for fermentation. Strain G117 produced 0.86 ± 0.07 g/L butanol and 53.4 ± 0.05 mL hydrogen directly from 60 g/L xylan provided that had undergone no prior enzymatic hydrolysis. After process optimization, the amount of butanol produced from xylan was increased to 1.24 ± 0.37 g/L. In contrast to traditional acetone‐butanol‐ethanol (ABE) solventogenic fermentation, xylan supported fermentation in strain G117 and negligible amount of acetone was produced. The expression of genes normally associated with acetone production (adc and ctfB2) were down‐regulated compared to xylose fed cultures. This lack of acetone production may greatly simplify downstream separation process. Moreover, higher amount of butanol (2.94 g/L) was produced from 16.99 g/L xylo‐oligosaccharides, suggesting a major role for strain G117 in butanol production from xylan and its oligosaccharides. The unique ability of strain G117 to produce a considerable amount of butanol directly from xylan without producing undesirable fermentation byproducts opens the door to the possibility of cost‐effective biofuels production in a single step. Biotechnol. Bioeng. 2016;113: 1702–1710. © 2016 Wiley Periodicals, Inc.
Mortality in individuals with intellectual disabilities in Finland
Authors: Arvio Maria , Salokivi Tommi , Tiitinen Aila , Haataja Leena 
Published: January 2016

AbstractObjectivesThis study aimed at ascertaining the standardized mortality ratios (SMR) for those with an intellectual disability (ID) in Finland.Materials and MethodsWe used the statistical database of the national insurance institution of Finland and Statistics Finland's mean population figures. We determined the number of individuals who received benefits (disability allowance, disability pension, or care allowance for pensioners) due to an ID diagnosis and the number of those whose benefit had been terminated due to death during the years 1996–2011.ResultsSMR for females with a mild ID (IQ 50–69) was 2.8 (95% CI: 2.60–3.01) and for males 2.0 (95% CI: 1.88–2.14), and for females with a severe ID (IQ <50) 5.2 (95% CI: 4.99–5.50) and for males 2.6 (95% CI: 2.48–2.72).ConclusionThis significant difference in the SMR figures between males and females with ID warrants further research.
Nanocomposites of Platinum/Metal–Organic Frameworks Coated with Metal–Organic Frameworks with Remarkably Enhanced Chemoselectivity for Cinnamaldehyde Hydrogenation
Authors: Liu Hongli , Chang Lina , Chen Liyu , Li Yingwei 
Published: January 2016

AbstractThe encapsulation of metal nanoparticles (MNPs) within metal–organic frameworks (MOFs) to form core–shell structural nanocomposites is one of the most promising methods to enhance the durability and selectivity of MOF‐supported metal catalysts. However, it is still a challenge to fully encapsulate tiny MNPs inside MOFs. Herein, we report a facile and general strategy to coat MOFs on the surface of Pt/MOFs by direct homoepitaxial growth. The obtained Pt/MOFs@MOFs nanocomposites retained the intrinsic properties (e.g., crystalline structure, pore texture, and surface area) of Pt/MOFs. Strikingly, the MOF‐coated materials exhibited a significantly enhanced chemoselectivity compared to the uncoated materials, for example, in the hydrogenation of cinnamaldehyde, the selectivity to cinnamyl alcohol through C=O hydrogenation was improved from 55 to 96 % at complete conversions of cinnamaldehyde. Moreover, Pt/MOFs@MOFs can be recycled without any remarkable loss in both activity and selectivity. The enhanced catalytic selectivity and stability of MNPs/MOFs could be related to the synergetic effects of the electron donation and nanoconfinement offered by the surrounding MOF networks.
Unique Use of Alkylation for Chemo‐Redox Activity by a PtIV Prodrug
Authors: Pathak Rakesh K. , Dhar Shanta 
Published: January 2016

AbstractResistance towards chemotherapeutics displayed by cancer cells is a significant stumbling block against fruitful cisplatin‐based therapy. A unique dual‐acting chemotherapeutic modality, Platin‐B, a prodrug of cisplatin and pipobroman‐mimicking alkylating agent, was constructed to circumvent tumor resistance. Platin‐B exhibited a superior cytotoxicity profile in cisplatin‐resistant cancer cells. Enhanced activity and the ability to overcome cancer‐induced resistance of Platin‐B was related to adduct formation with intracellular glutathione, followed by the activity of Platin‐B on the mitochondria of cells, along with its conventional nuclear activity. Alkylating moieties present on Platin‐B enhanced its cellular and subcellular concentration and protected it from early drug sequestration by biological thiols.
Reactions of 2‐Substituted Pyridines with Titanocenes and Zirconocenes: Coupling versus Dearomatisation
Authors: Reiß Fabian , Altenburger Kai , Becker Lisanne , Schubert Kathleen , Jiao Haijun , Spannenberg Anke , Hollmann Dirk , Arndt Perdita , Rosenthal Uwe 
Published: January 2016

AbstractReactions of group 4 metallocene sources with 2‐substituted pyridines were investigated to evaluate their coordination type between innocent and reductive dearomatisation as well as to probe the possibility for couplings. A dependence on the cyclopentadienyl ligands (Cp, Cp*), the metals (Ti, Zr), and the substrates (2‐phenyl‐, 2‐acetyl‐, and 2‐iminopyridine) was observed. While 2‐phenylpyridine is barely reactive, 2‐acetylpyridine reacts vigorously with the Cp‐substituted complexes and selectively with their Cp* analogues. With 2‐iminopyridine, in all cases selective reactions were observed. In the isolated [Cp2Ti], [Cp2Zr], and [Cp*2Zr] compounds the substrate coordinates by its pyridyl ring and the unsaturated side‐chain. Subsequently, the pyridine was dearomatised, which is most pronounced in the [Cp*2Zr] compounds. Using [Cp*2Ti] leads to the unexpected paramagnetic complexes [Cp*2TiIII(N,O‐acpy)] and [Cp*2TiIII(N,N′‐impy)]. This highlights the non‐innocent character of the pyridyl substrates.
Towards the Development of Structure‐Selective G‐Quadruplex‐Binding Indolo[3,2‐b]quinolines
Authors: Funke Andrea , Dickerhoff Jonathan , Weisz Klaus 
Published: January 2016

AbstractThe interaction of phenyl‐substituted indolo[3,2‐b]quinolines with DNA G‐quadruplexes of different topology were studied by using a combination of spectroscopic and calorimetric methodologies. N5‐Methylated indoloquinoline derivatives (MePIQ) with an aminoalkyl side chain exhibit high affinities for the parallel‐stranded MYC quadruplex and a (3+1)‐hybrid structure combined with an excellent discrimination against the antiparallel thrombin‐binding aptamer (TBA) and the human telomeric (HT) quadruplexes. Dissociation constants for the binding of the ligand to the MYC quadruplex are in the submicromolar range, being below the corresponding dissociation constants for the antiparallel‐stranded quadruplexes by about one order of magnitude. Competition experiments with double‐helical DNA reveal the impact of indoloquinoline structural features on the selectivity for the parallel quadruplex relative to duplex DNA. Based on a calorimetric analysis binding to MYC is shown to be equally driven by favorable enthalpic and entropic contributions with no significant impact on the type of cation present.
Enantiopure Ferrocene‐Based Planar‐Chiral Iridacycles: Stereospecific Control of Iridium‐Centred Chirality
Authors: Arthurs Ross A. , Ismail Muhammad , Prior Christopher C. , Oganesyan Vasily S. , Horton Peter N. , Coles Simon J. , Richards Christopher J. 
Published: January 2016

AbstractReaction of [IrCp*Cl2]2 with ferrocenylimines (Fc=NAr, Ar=Ph, p‐MeOC6H4) results in ferrocene C−H activation and the diastereoselective synthesis of half‐sandwich iridacycles of relative configuration Sp*,RIr*. Extension to (S)‐2‐ferrocenyl‐4‐(1‐methylethyl)oxazoline gave highly diastereoselective control over the new elements of planar chirality and metal‐based pseudo‐tetrahedral chirality, to give both neutral and cationic half‐sandwich iridacycles of absolute configuration Sc,Sp,RIr. Substitution reactions proceed with retention of configuration, with the planar chirality controlling the metal‐centred chirality through an iron–iridium interaction in the coordinatively unsaturated cationic intermediate.
General Assembly of Twisted Trigonal‐Prismatic Nonanuclear Silver(I) Clusters
Authors: Li Xiao‐Yu , Su Hai‐Feng , Zhou Rui‐Qi , Feng Sheng , Tan Yuan‐Zhi , Wang Xing‐Po , Jia Jiong , Kurmoo Mohamedally , Sun Di , Zheng Lan‐Sun 
Published: January 2016

AbstractA general class of C3‐symmetric Ag9 clusters, [Ag9S(tBuC6H4S)6(dpph)3(CF3SO3)] (1), [Ag9(tBuC6H4S)6(dpph)3(CF3SO3)2]⋅CF3SO3 (2), [Ag9(tBuC6H4S)6(dpph)3(NO3)2] ⋅NO3 (3), and [Ag9(tBuC6H4S)7(dpph)3(Mo2O7)0.5]2⋅2 CF3COO (4) (dpph=1,6‐bis(diphenylphosphino)hexane), with a twisted trigonal‐prism geometry was isolated by the reaction of polymeric {(HNEt3)2[Ag10(tBuC6H4S)12]}n, 1,6‐bis(diphenylphosphino)hexane, and various silver salts under solvothermal conditions. The structures consist of discrete clusters constructed from a girdling Ag9 twisted trigonal prism with the top and bottom trigonal faces capped by diverse anions (i.e., S2− and CF3SO3− for compound 1, 2×CF3SO3− for compound 2, 2×NO3− for compound 3, and tBuC6H4S− and Mo2O72− for compound 4). This trigonal prism is bisected by another shrunken Ag3 trigon at its waist position. Interestingly, two inversion‐related Ag9 trigonal‐prismatic clusters are dimerized by the Mo2O72− ion in compound 4. The twist is amplified by the bulkier thiolate, which also introduces high steric‐hindrance for the capping ligand, that is, the longer dpph ligand. Four more silver–sulfur clusters (namely, compounds 5–8) with their nuclearity ranging from 6–10 were solely characterized by single‐crystal X‐ray diffraction to verify the above‐described synergetic effect of mixed ligands in the construction of Ag9 twisted trigonal prisms. Surprisingly, only cluster 1 emits yellow luminescence at λ=584 nm at room temperature, which may be attributed to a charge transfer from the S 3p orbital to the Ag 5s orbital, or mixed with metal‐centered (MC) d10→d9s1 transitions. Upon cooling from 300 to 80 K, the emission intensity was enhanced along with a hypsochromic shift. The good linear relationship between the maximum emission intensity and the temperature for compound 1 in the range of 180–300 K indicates that this is a promising molecular luminescent thermometer. Furthermore, cyclic voltammetric studies indicated that the diffusion‐ and surface‐controlled redox processes were determined for compounds 1 and 3 as well as compound 4, respectively.
Resolution of Rac‐Bambuterol via Diastereoisomeric Salt Formation with o‐Chloromandelic Acid and Differences in the Enantiomers' Pharmacodynamical Effects in Guinea Pigs and Beagles
Authors: Wu Jie , Liu Fei , Wang Shanping , Wang Hongjun , Liu Qing , Song Xinghan , Li Junxiao , Xu Ling , Tan Wen 
Published: January 2016

AbstractIn this study an enantioseparation method for rac‐bambuterol (5‐(2‐(tert‐butylamino)‐1‐hydroxyethyl)‐1,3‐phenylene bis(dimethylcarbamate)) via diastereoisomeric salt formation with o‐chloromandelic acid was developed. The enantiomeric excess (ee) values and chemical purities of the desired products were confirmed by high‐performance liquid chromatography (HPLC) using chiral stationary phase and reverse‐phase HPLC analyses, respectively. The ee values and the chemical purities both exceeded 99%. Animal experiments showed that (R)‐bambuterol was a potent inhibitor for histamine‐induced asthma reactions. (S)‐bambuterol was ineffective in relaxing the airways. Both enantiomers increased heart rates in beagles. Therefore, replacing rac‐bambuterol with (R)‐bambuterol could be beneficial for asthma patients. Chirality 28:306–312, 2016. © 2016 Wiley Periodicals, Inc.
Application of Site‐Specific Spin Labeling for NMR Detecting Inhibitor‐Induced Conformational Change of HIV‐1 Reverse Transcriptase
Authors: Seetaha Supaporn , Yagi‐Utsumi Maho , Yamaguchi Takumi , Ishii Kentaro , Hannongbua Supa , Choowongkomon Kiattawee , Kato Koichi 
Published: January 2016

AbstractParamagnetism‐assisted nuclear magnetic resonance (NMR) techniques can provide long‐range structural information complemented with local information derived from chemical‐shift perturbation and nuclear Overhauser effect data. Here, we address the application of paramagnetic relaxation enhancement (PRE) to detect inhibitor‐induced conformational change of a drug target protein using human immunodeficiency virus type 1 reverse transcriptase (HIV‐1 RT) as a model protein. Using a site‐specific spin‐labeled HIV‐1 RT mutant with selective 13C labeling, conformation‐dependent PREs were successfully observed reflecting the stabilization of an open conformation of this enzyme caused by inhibitor binding. This study demonstrates that the paramagnetism‐assisted NMR approach offers an alternative strategy in protein‐based drug screening to identify allosteric inhibitors of a target protein.
Structural and Electrochemical Study of Vanadium‐Doped TiO2 Ramsdellite with Superior Lithium Storage Properties for Lithium‐Ion Batteries
Authors: Pérez‐Flores Juan Carlos , Hoelzel Markus , García‐Alvarado Flaviano , Kuhn Alois 
Published: January 2016

AbstractTitanium‐oxide‐based materials are considered attractive and safe alternatives to carbonaceous anodes in Li‐ion batteries. In particular, the ramsdellite form TiO2(R) is known for its superior lithium‐storage ability as the bulk material when compared with other titanates. In this work, we prepared V‐doped lithium titanate ramsdellites with the formula Li0.5Ti1−xVxO2 (0≤x≤0.5) by a conventional solid‐state reaction. The lithium‐free Ti1−xVxO2 compounds, in which the ramsdellite framework remains virtually unaltered, are easily obtained by a simple aqueous oxidation/ion‐extraction process. Neutron powder diffraction is used to locate the Li channel site in Li0.5Ti1−xVxO2 compounds and to follow the lithium extraction by difference‐Fourier maps. Previously delithiated Ti1−xVxO2 ramsdellites are able to insert up to 0.8 Li+ per transition‐metal atom. The initial gravimetric capacities of 270 mAh g−1 with good cycle stability under constant current discharge conditions are among the highest reported for bulk TiO2‐related intercalation compounds for the threshold of one e− per formula unit.
Evaluation of a novel automated volumetric flow cytometer for absolute CD4+ T lymphocyte quantitation
Authors: Gossez Morgane , Malcus Christophe , Demaret Julie , Frater John , Poitevin‐Later Françoise , Monneret Guillaume 
Published: January 2016

BackgroundBead‐based single platform cytometry technology (SPT) is the gold standard when performing CD4 absolute counting. However, it presents drawbacks as precision depends on various critical steps (for example, pipetting methodology, overtime stability of beads, stability of fluidics, regular recalibration…) and thus requires skilled operators. The fully automated volumetric SPT AQUIOS CL (Beckman Coulter) has recently emerged as an alternative with no need of beads. It may help improving results standardisation and fulfilling requirements for certification (ISO 15189). In this study, we assessed SPT AQUIOS CL performances in accordance to requirements for ISO 15189 accreditation.MethodsWe evaluated repeatability and reproducibility (precision), bias (trueness), uncertainty (total error), range limits (linearity, quantification, detection limits), and inter‐reagent/inter‐sample contaminations in enumerating CD4+ T‐cells. Concomitantly, we compared AQUIOS CL CD4+ T‐cell values with the results obtained with our routine bead‐based SPT (that is, FC500 Beckman Coulter, bead‐based SPT), on blood samples from 148 patients representative of clinical laboratory routine workload.ResultsEvery result (repeatability, reproducibility, trueness, total error) was below the acceptable thresholds proposed in international recommendations. Contamination results and range limits (linearity, quantification, and detection limits) were all found perfectly suitable to routine analysis. The comparison between AQUIOS CL and FC500 exhibited excellent correlation and agreement (PearsonR = 0.99,P < 0.001; Lin's concordance correlation coefficient: Linρc = 0.991, Cb = 0.999), and Bland‐Altman analysis did not reveal any systematic error.ConclusionsOur results demonstrate that, upon subsequent validation in more routine conditions, the AQUIOS CL could be a suitable tool for clinical flow cytometry laboratories facing accreditation process. © 2016 International Clinical Cytometry Society
Testosterone and cortisol concentrations vary with reproductive status in wild female red deer
Authors: Pavitt Alyson T. , Pemberton Josephine M. , Kruuk Loeske E. B. , Walling Craig A. 
Published: January 2016

AbstractAlthough hormones are key regulators of many fitness and life history traits, the causes of individual level variation in hormones, particularly in wild systems, remain understudied. Whilst we know that androgen and glucocorticoid levels vary within and among individuals in mammalian populations, how this relates to key reproductive processes such as gestation and lactation, and their effects on a female's measurable hormone levels are poorly understood in wild systems. Using fecal samples collected from females in a wild red deer population between 2001 and 2013, we explore how fecal androgen (FAM) and cortisol (FCM) metabolite concentrations change with age and season, and how individual differences relate to variation in reproductive state. Both FAM and FCM levels increase toward parturition, although this only affects FCM levels in older females. FCM levels are also higher when females suckle a male rather than a female calf, possibly due to the higher energetic costs of raising a son. This illustrates the importance of accounting for a female's life history and current reproductive status, as well as temporal variation, when examining individual differences in hormone levels. We discuss these findings in relation to other studies of mammalian systems and in particular to the relatively scarce information on variation in natural levels of hormones in wild populations.
Implications of recurrent disturbance for genetic diversity
Authors: Davies Ian D. , Cary Geoffrey J. , Landguth Erin L. , Lindenmayer David B. , Banks Sam C. 
Published: January 2016

AbstractExploring interactions between ecological disturbance, species’ abundances and community composition provides critical insights for ecological dynamics. While disturbance is also potentially an important driver of landscape genetic patterns, the mechanisms by which these patterns may arise by selective and neutral processes are not well‐understood. We used simulation to evaluate the relative importance of disturbance regime components, and their interaction with demographic and dispersal processes, on the distribution of genetic diversity across landscapes. We investigated genetic impacts of variation in key components of disturbance regimes and spatial patterns that are likely to respond to climate change and land management, including disturbance size, frequency, and severity. The influence of disturbance was mediated by dispersal distance and, to a limited extent, by birth rate. Nevertheless, all three disturbance regime components strongly influenced spatial and temporal patterns of genetic diversity within subpopulations, and were associated with changes in genetic structure. Furthermore, disturbance‐induced changes in temporal population dynamics and the spatial distribution of populations across the landscape resulted in disrupted isolation by distance patterns among populations. Our results show that forecast changes in disturbance regimes have the potential to cause major changes to the distribution of genetic diversity within and among populations. We highlight likely scenarios under which future changes to disturbance size, severity, or frequency will have the strongest impacts on population genetic patterns. In addition, our results have implications for the inference of biological processes from genetic data, because the effects of dispersal on genetic patterns were strongly mediated by disturbance regimes.
Fluctuating selection on basal metabolic rate
Authors: Nilsson Johan F. , Nilsson Jan‐Åke 
Published: January 2016

AbstractBMR (Basal metabolic rate) is an important trait in animal life history as it represents a significant part of animal energy budgets. BMR has also been shown to be positively related to sustainable work rate and maximal thermoregulatory capacity. To this date, most of the studies have focused on the causes of interspecific and intraspecific variation in BMR, and fairly little is known about the fitness consequences of different metabolic strategies. In this study, we show that winter BMR affects local survival in a population of wild blue tits (Cyanistes caeruleus), but that the selection direction differs between years. We argue that this fluctuating selection is probably a consequence of varying winter climate with a positive relation between survival and BMR during cold and harsh conditions, but a negative relation during mild winters. This fluctuating selection can not only explain the pronounced variation in BMR in wild populations, but will also give us new insights into how energy turnover rates can shape the life‐history strategies of animals. Furthermore, the study shows that the process of global warming may cause directional selection for a general reduction in BMR, affecting the general life‐history strategy on the population level.