bluuebunny/crossref_metadata_2025_split huggingface dataset:
Water‐Splitting Catalysis and Solar Fuel Devices: Artificial Leaves on the Move
Authors: Joya Khurram Saleem , Joya Yasir F. , Ocakoglu Kasim , van de Krol Roel 
Published: August 2013

AbstractThe development of new energy materials that can be utilized to make renewable and clean fuels from abundant and easily accessible resources is among the most challenging and demanding tasks in science today. Solar‐powered catalytic water‐splitting processes can be exploited as a source of electrons and protons to make clean renewable fuels, such as hydrogen, and in the sequestration of CO2 and its conversion into low‐carbon energy carriers. Recently, there have been tremendous efforts to build up a stand‐alone solar‐to‐fuel conversion device, the “artificial leaf”, using light and water as raw materials. An overview of the recent progress in electrochemical and photo‐electrocatalytic water splitting devices is presented, using both molecular water oxidation complexes (WOCs) and nano‐structured assemblies to develop an artificial photosynthetic system.
Preparation of aqueous soluble polyamides from renewable succinic acid and citric acid as a new approach to design bio‐inspired polymers
Authors: Jiang Man , Chen Guangsong , Lu Ping , Dong Jian 
Published: August 2013

ABSTRACTA novel type of aqueous soluble polyamides were prepared as renewable substitutes for ecologically benign poly(aspartic acid) by polymerization of succinic acid ester and hexamethylene diamine in the presence of citric acid ester. The copolymerization resulted in the formation of poly(amide imide) intermediates, which were hydrolyzed to aqueous solutions of polyamides. The hydrolyzed products were confirmed to be copolymers of succinamide and citramide with COOH side chains, similar to poly(aspartic acid). The polyamides showed strong chelating abilities to Ca2+ and Pb2+ metals, comparable to poly(aspartic acid). Interestingly, they also demonstrated antifreeze activities in water by reducing the ice fractions. The polyamides represent a new class of metal chelators and antifreeze protein mimics derived from succinamide and citramide. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39807.
A Geometric Morphometric Analysis of the Medial Tibial Condyle of African Hominids
Authors: Sylvester Adam D. 
Published: August 2013

ABSTRACTAlthough the hominid knee has been heavily scrutinized, shape variation of the medial tibial condyle has yet to be described. Humans, chimpanzees, and gorillas differ in the shape of their medial femoral condyles and in their capacity for external and internal rotation of the tibia relative to the femur. I hypothesize that these differences should be reflected in the shape of the medial tibial condyle of these hominids. Here I use geometric morphometric techniques to uncover shape differences between the medial tibial condyles of humans, chimpanzees, and gorillas. Humans are distinguished from the other two species by having a much more oval‐shaped medial tibial condyle, while those of chimpanzees and gorillas are more triangular in outline. Gorillas (especially males) are distinguished by having more concavely‐curved condyles (mediolateral direction), which is interpreted as an effect of heavy loading through the medial compartment of the knee in conjunction with differences in the degree of arboreality. Anat Rec, 296:1518–1525, 2013. © 2013 Wiley Periodicals, Inc.
TRAIL is Involved in the Tumoricidal Activity of Mouse Natural Killer Cells Stimulated by Newcastle Disease Virus in Vitro
Authors: Song De‐Zhi , Liang Ying , Xiao Qing , Yin Jun , Gong Jin‐Ling , Lai Zhen‐Ping , Zhang Zeng‐Feng , Gao Ling‐Xi , Fan Xiao‐Hui 
Published: August 2013

ABSTRACTNewcastle disease virus (NDV) is a potential antitumor agent, and its antitumor effect has been evaluated in preclinical tests. However, the mechanisms of NDV‐based antitumor therapy are still not completely clear. In the present study we found that NDV‐stimulation enhanced the killing ability of mouse spleen natural killer (NK) cells towards mouse hepatoma cell lines, and tumor necrosis factor (TNF)‐related apoptosis‐inducing ligand (TRAIL) plays an important role in this tumoricidal activity. NDV stimulation induced up‐regulation of TRAIL both at the mRNA and protein levels in NK cells. Blocking TRAIL by antibody (Ab) almost completely eliminated the killing effect of NK cells on hepatoma cell lines. Furthermore, neutralizing interferon (IFN)‐γ by Ab could inhibit TRAIL expression and tumoricidal activity of NDV‐stimulated NK cells. These results indicated a substantial role of TRAIL as an effector molecule in NDV‐induced NK cells mediated tumoricidal activity. The NDV stimulation triggered TRAIL expression in mouse spleen NK cells could be mediated by IFN‐γ induction. Anat Rec, 296:1552–1560, 2013. © 2013 Wiley Periodicals, Inc.
Incorporation of Nucleoside Probes Opposite O6‐Methylguanine by Sulfolobus solfataricus DNA Polymerase Dpo4: Importance of Hydrogen Bonding
Authors: Stornetta Alessia , Angelov Todor , Guengerich F. Peter , Sturla Shana J. 
Published: August 2013

AbstractO6‐Methylguanine (O6‐MeG) is a mutagenic DNA lesion, arising from the action of methylating agents on guanine (G) in DNA. Dpo4, an archaeal low‐fidelity Y‐family DNA polymerase involved in translesion DNA synthesis (TLS), is a model for studying how human Y‐family polymerases bypass DNA adducts. Previous work showed that Dpo4‐mediated dTTP incorporation is favored opposite O6‐MeG rather than opposite G. However, factors influencing the preference of Dpo4 to incorporate dTTP opposite O6‐MeG are not fully defined. In this study, we investigated the influence of structural features of incoming dNTPs on their enzymatic incorporation opposite O6‐MeG in a DNA template. To this end, we utilized a new fluorescence‐based primer extension assay to evaluate the incorporation efficiency of a panel of synthetic dNTPs opposite G or O6‐MeG by Dpo4. In single‐dNTP primer extension studies, the synthetic dNTPs were preferentially incorporated opposite G, relative to O6‐MeG. Moreover, pyrimidine‐based dNTPs were generally better incorporated than purine‐based syn‐conformation dNTPs. The results suggest that hydrophobicity of the incoming dNTP appears to have little influence on the process of nucleotide selection by Dpo4, with hydrogen bonding capacity being a major influence. Additionally, modifications at the C2‐position of dCTP increase the selectivity for incorporation opposite O6‐MeG without a significant loss of efficiency.
Mental retardation‐related protease, motopsin (prss12), binds to the BRICHOS domain of the integral membrane protein 2a
Authors: Mitsui Shinichi , Osako Yoji , Yuri Kazunari 
Published: August 2013

AbstractMotopsin (prss12), a mosaic serine protease secreted by neuronal cells, is believed to be important for cognitive function, as the loss of its function causes severe nonsyndromic mental retardation. To understand the molecular role of motopsin, we identified the integral membrane protein 2a (Itm2a) as a motopsin‐interacting protein using a yeast two‐hybrid system. A pull‐down assay showed that the BRICHOS domain of Itm2a was essential for this interaction. Motopsin and Itm2a co‐localized in COS cells and in cultured neurons when transiently expressed in these cells. Both proteins were co‐immunoprecipitated from lysates of these transfected COS cells. Itm2a was strongly detected in a brain lysate prepared between postnatal day 0 and 10, during which period motopsin protein was also enriched in the brain. Immunohistochemistry detected Itm2a as patchy spots along endothelial cells of brain capillaries (which also expressed myosin II regulatory light chain [RLC]), and on glial fibrillary acidic protein (GFAP)‐positive processes in the developing cerebral cortex. The data raise the possibility that secreted motopsin interacts with endothelial cells in the developing brain.
Analysis of epothilone B‐induced cell death in normal ovarian cells
Authors: Rogalska Aneta , Gajek Arkadiusz , Marczak Agnieszka 
Published: August 2013

AbstractWe have investigated the mode of cell death induced by a new microtubule‐stabilizing agent, epothilone B (EpoB, patupilone), and a clinically used medicine, paclitaxel (PTX), in normal ovarian cells. Using fluorescence microscopy, polyacrylamide gel electrophoresis preceding Western blot analysis, as well as spectrofluorimetric and colorimetric detection, we demonstrate that, compared to EpoB, PTX induced high time‐dependent morphological and biochemical changes typical of apoptosis. Induction of apoptosis followed an early increase in p53 levels. Apoptosis reached its maximum at 24–48 h. At the same time, there was a significant increase in caspase‐9 and ‐3 activity and PARP fragmentation, which suggests that an intrinsic path was involved. Apoptosis in MM14 cells was increased more by PTX than EpoB, and also induced more necrosis responsible for inflammation (1.4‐fold) than EpoB.
Human foreskin fibroblast‐like stromal cells can differentiate into functional hepatocytic cells
Authors: Huang Hsing‐I , Chen Shao‐Kuan , Wang Robert Y.‐L. , Shen Chia‐Rui , Cheng Yu‐Che 
Published: August 2013

AbstractForeskin fibroblast‐like stromal cells (FDSCs) are progenitors isolated from human tissue that can differentiate into diverse cell types. Many types of stem cells can differentiate into hepatocyte‐like cells, which could be used for drug testing or in liver regeneration therapy, but whether FDSCs can be converted into functional hepatocytes is unknown. FDSCs show divergent properties when cultured in distinct media, forming spheres in Dulbecco's modified Eagle's medium (DMEM) containing F12, epidermal growth factor (EGF), and basic fibroblast growth factor (b‐FGF), but have fibroblast‐like morphology when cultured in DMEM‐based growth medium. Both cell populations express the typical mesenchymal stem cell markers CD90, CD105, and CD73, but the p75 neurotrophin receptor (p75NTR) was detected only in FDSC spheres. Both types of FDSCs can differentiate into hepatocyte‐like cells, which express typical liver markers, including albumin and hepatocyte paraffin 1 (Hep Par1), along with liver‐specific biological activities. When plasmids containing the human hepatitis B virus (HBV) genome were transfected transiently into FDSCs, differentiated hepatocyte‐like cells secrete large amounts of HBe and HBs antigens. FDSCs could be used for clinical hepatic therapy and/or serve as a model of HBV.
Evaluating cis‐2,6‐Dimethylpiperidide (cis‐DMP) as a Base Component in Lithium‐Mediated Zincation Chemistry
Authors: Armstrong David R. , Garden Jennifer A. , Kennedy Alan R. , Leenhouts Sarah M. , Mulvey Robert E. , O'Keefe Philip , O'Hara Charles T. , Steven Alan 
Published: August 2013

AbstractMost recent advances in metallation chemistry have centred on the bulky secondary amide 2,2,6,6‐tetramethylpiperidide (TMP) within mixed metal, often ate, compositions. However, the precursor amine TMP(H) is rather expensive so a cheaper substitute would be welcome. Thus this study was aimed towards developing cheaper non‐TMP based mixed‐metal bases and, as cis‐2,6‐dimethylpiperidide (cis‐DMP) was chosen as the alternative amide, developing cis‐DMP zincate chemistry which has received meagre attention compared to that of its methyl‐rich counterpart TMP. A new lithium diethylzincate, [(TMEDA)LiZn(cis‐DMP)Et2] (TMEDA=N,N,N′,N′‐tetramethylethylenediamine) has been synthesised by co‐complexation of Li(cis‐DMP), Et2Zn and TMEDA, and characterised by NMR (including DOSY) spectroscopy and X‐ray crystallography, which revealed a dinuclear contact ion pair arrangement. By using N,N‐diisopropylbenzamide as a test aromatic substrate, the deprotonative reactivity of [(TMEDA)LiZn(cis‐DMP)Et2] has been probed and contrasted with that of the known but previously uninvestigated di‐tert‐butylzincate, [(TMEDA)LiZn(cis‐DMP)tBu2]. The former was found to be the superior base (for example, producing the ortho‐deuteriated product in respective yields of 78 % and 48 % following D2O quenching of zincated benzamide intermediates). An 88 % yield of 2‐iodo‐N,N‐diisopropylbenzamide was obtained on reaction of two equivalents of the diethylzincate with the benzamide followed by iodination. Comparisons are also drawn using 1,1,1,3,3,3‐hexamethyldisilazide (HMDS), diisopropylamide and TMP as the amide component in the lithium amide, Et2Zn and TMEDA system. Under certain conditions, the cis‐DMP base system was found to give improved results in comparison to HMDS and diisopropylamide (DA), and comparable results to a TMP system. Two novel complexes isolated from reactions of the di‐tert‐butylzincate and crystallographically characterised, namely the pre‐metallation complex [{(iPr)2N(Ph)CO}LiZn(cis‐DMP)tBu2] and the post‐metallation complex [(TMEDA)Li(cis‐DMP){2‐[1‐C(=O)N(iPr)2]C6H4}Zn(tBu)], shed valuable light on the structures and mechanisms involved in these alkali‐metal‐mediated zincation reactions. Aspects of these reactions are also modelled by DFT calculations.
A Hybrid Ring‐Opening Metathesis Polymerization Catalyst Based on an Engineered Variant of the β‐Barrel Protein FhuA
Authors: Philippart Freddi , Arlt Marcus , Gotzen Steve , Tenne Stefanie‐Joana , Bocola Marco , Chen Hsui‐Hui , Zhu Leilei , Schwaneberg Ulrich , Okuda Jun 
Published: August 2013

AbstractA β‐barrel protein hybrid catalyst was prepared by covalently anchoring a Grubbs–Hoveyda type olefin metathesis catalyst at a single accessible cysteine amino acid in the barrel interior of a variant of β‐barrel transmembrane protein ferric hydroxamate uptake protein component A (FhuA). Activity of this hybrid catalyst type was demonstrated by ring‐opening metathesis polymerization of a 7‐oxanorbornene derivative in aqueous solution.
Activation of Methane by Os+: Guided‐Ion‐Beam and Theoretical Studies
Authors: Armentrout P. B. , Parke Laura , Hinton Christopher , Citir Murat 
Published: August 2013

AbstractActivation of methane by the third‐row transition‐metal cation Os+ is studied experimentally by examining the kinetic energy dependence of reactions of Os+ with CH4 and CD4 using guided‐ion‐beam tandem mass spectrometry. A flow tube ion source produces Os+ in its electronic ground state and primarily in the ground spin–orbit level. Dehydrogenation to form [Os,C,2 H]++H2 is exothermic, efficient, and the only process observed at low energies for reaction of Os+ with methane, whereas OsH+ dominates the product spectrum at higher energies. The kinetic energy dependences of the cross sections for several endothermic reactions are analyzed to give 0 K bond dissociation energies (in eV) of D0(Os+C)=6.20±0.21, D0(Os+CH)=6.77±0.15, and D0(Os+CH3)=3.00±0.17. Because it is formed exothermically, D0(Os+CH2) must be greater than 4.71 eV, and a speculative interpretation suggests the exothermicity exceeds 0.6 eV. Quantum chemical calculations at the B3LYP/def2‐TZVPP level show reasonable agreement with the experimental bond energies and with previous theoretical values available. Theory also provides the electronic structures of the product species as well as intermediates and transition states along the reactive potential energy surfaces. Notably, the structure of the dehydrogenation product is predicted to be HOsCH+, rather than OsCH2+, in contrast to previous work.
Neural stem cell apoptosis after low‐methylmercury exposures in postnatal hippocampus produce persistent cell loss and adolescent memory deficits
Authors: Sokolowski Katie , Obiorah Maryann , Robinson Kelsey , McCandlish Elizabeth , Buckley Brian , DiCicco‐Bloom Emanuel 
Published: August 2013

ABSTRACTThe developing brain is particularly sensitive to exposures to environmental contaminants. In contrast to the adult, the developing brain contains large numbers of dividing neuronal precursors, suggesting that they may be vulnerable targets. The postnatal day 7 (P7) rat hippocampus has populations of both mature neurons in the CA1–3 region as well as neural stem cells (NSC) in the dentate gyrus (DG) hilus, which actively produce new neurons that migrate to the granule cell layer (GCL). Using this well‐characterized NSC population, we examined the impact of low levels of methylmercury (MeHg) on proliferation, neurogenesis, and subsequent adolescent learning and memory behavior. Assessing a range of exposures, we found that a single subcutaneous injection of 0.6 µg/g MeHg in P7 rats induced caspase activation in proliferating NSC of the hilus and GCL. This acute NSC death had lasting impact on the DG at P21, reducing cell numbers in the hilus by 22% and the GCL by 27%, as well as reductions in neural precursor proliferation by 25%. In contrast, non‐proliferative CA1–3 pyramidal neuron cell number was unchanged. Furthermore, animals exposed to P7 MeHg exhibited an adolescent spatial memory deficit as assessed by Morris water maze. These results suggest that environmentally relevant levels of MeHg exposure may decrease NSC populations and, despite ongoing neurogenesis, the brain may not restore the hippocampal cell deficits, which may contribute to hippocampal‐dependent memory deficits during adolescence. © 2013 Wiley Periodicals, Inc. Develop Neurobiol 73: 936–949, 2013
Impact of Different Surfactants and their Mixtures on Methane‐Hydrate Formation
Authors: Fazlali Alireza , Kazemi Seyedeh‐Atieh , Keshavarz‐Moraveji Mostafa , Mohammadi Amir H. 
Published: August 2013

AbstractGas hydrates can be used as a potential means for natural gas storage. Design of a gas‐hydrate‐based unit requires accurate knowledge of hydrate‐formation kinetics especially in the presence of promoters. In this study, the effects of sodium dodecyl sulfate (SDS), hexa decyl trimethyl ammonium bromide (HTABr), polyoxy ethylene(20) cetyl ether (Brij‐58) and mixtures of SDS with HTABr and Brij‐58 have been investigated to determine their influence on the methane‐hydrate‐formation kinetics and thermodynamics. The study on the kinetics of hydrate formation is focused on the induction time and hydrate‐formation rate. It is found that induction time of hydrate formation in the presence of a promoter is reduced considerably for each test compared with a pure water test. The minimum value of the induction time is found for a mixture of SDS (500 ppm) with HTABr (700 ppm). All of the surfactants and their mixtures can be designated as hydrate‐formation promoters in the concentration ranges studied in the present work and can increase the hydrate‐formation rate. SDS at a concentration of 500 ppm is determined to be the best hydrate‐formation promoter among the surfactants tested. The percent conversion of methane to hydrate is increased in the presence of these surfactants at the end of hydrate formation. The maximum value of the conversion is observed for the 500 ppm concentration of SDS. The results demonstrate that these surfactants and their corresponding mixtures have no significant effect on the thermodynamics of methane hydrate formation.
Review of Maximum‐Power‐Point Tracking Techniques for Solar‐Photovoltaic Systems
Authors: Rawat Rahul , Chandel S. S. 
Published: August 2013

AbstractSolar‐photovoltaic systems are being widely used and promoted worldwide for pollution‐free power generation. The power extraction from solar photovoltaic (PV) systems can be maximized by using maximum‐power‐point tracking (MPPT) techniques between the photovoltaic array and the load. The MPPT technique searches the maximum‐power‐point and command system to enable operation at that point and enrich the overall efficiency of PV system. Substantial research has been performed on MPPT techniques to improve the efficiency, simplicity, response time, and steady‐state error. In this paper, a study of 21 different maximum power point tracking techniques used in photovoltaic systems has been performed to provide the latest update on conventional and advanced techniques and highlight the main features and limitations. The modified variable step incremental conductance technique is found to be the best among all in terms of steady‐state error, response time, convergence time, and efficiency. Possible areas of further research are also identified.
Bone Strength and Structural Deficits in Children and Adolescents With a Distal Forearm Fracture Resulting From Mild Trauma
Authors: Farr Joshua N , Amin Shreyasee , Melton L Joseph , Kirmani Salman , McCready Louise K , Atkinson Elizabeth J , Müller Ralph , Khosla Sundeep 
Published: August 2013

ABSTRACT

Although distal forearm fractures (DFFs) are common during childhood and adolescence, it is unclear whether they reflect underlying skeletal deficits or are simply a consequence of the usual physical activities, and associated trauma, during growth. Therefore, we examined whether a recent DFF, resulting from mild or moderate trauma, is related to deficits in bone strength and cortical and trabecular bone macro- and microstructure compared with nonfracture controls. High-resolution peripheral quantitative computed tomography was used to assess micro-finite element-derived bone strength (ie, failure load) and to measure cortical and trabecular bone parameters at the distal radius and tibia in 115 boys and girls with a recent (&lt;1 year) DFF and 108 nonfracture controls aged 8 to 15 years. Trauma levels (mild versus moderate) were assigned based on a validated classification scheme. Compared with sex-matched controls, boys and girls with a mild-trauma DFF (eg, fall from standing height) showed significant deficits at the distal radius in failure load (–13% and –11%, respectively; p &lt; 0.05) and had higher (“worse”) fall load-to-strength ratios (both +10%; p &lt; 0.05 for boys and p = 0.06 for girls). In addition, boys and girls with a mild-trauma DFF had significant reductions in cortical area (–26% and –23%, respectively; p &lt; 0.01) and cortical thickness (–14% and –13%, respectively; p &lt; 0.01) compared with controls. The skeletal deficits in the mild-trauma DFF patients were generalized, as similar changes were present at the distal tibia. By contrast, both boys and girls with a moderate-trauma DFF (eg, fall from a bicycle) had virtually identical values for all of the measured bone parameters compared with controls. In conclusion, DFFs during growth have two distinct etiologies: those owing to underlying skeletal deficits leading to fractures with mild trauma versus those owing to more significant trauma in the setting of normal bone strength. © 2014 American Society for Bone and Mineral Research.