bluuebunny/crossref_metadata_2025_split huggingface dataset:
Catalytic Diamino‐Sugar‐Assisted Enantioselective Hydrogenation
Authors: Böge Matthias , Heck Jürgen 
Published: May 2015

AbstractCarbohydrate ligands have been studied in transition‐metal‐catalyzed hydrogenations in recent decades. Herein, we report the diastereoselective synthesis of trans‐dichlorido(bisphosphane)ruthenium(II) complexes with four different methyl 2,3‐diamino‐4,6‐O‐benzylidene‐2,3‐dideoxy‐α‐D‐hexopyranosides and their application as catalyst precursors in asymmetric hydrogenation reactions. Depending on the hexopyranose, an enantiomeric excess of up to 78 % was obtained.
Binuclear Sulfide Niobium Clusters Coordinated by Diimine Ligands: Synthesis, Structure, Photocatalytic Activity and Optical Limiting Properties
Authors: Rogachev Alexander V. , Gushchin Artem L. , Abramov Pavel A. , Kozlova Ekaterina A. , Vicent Cristian , Piryazev Dmitry , Barlow Adam , Samoc Marek , Humphrey Mark G. , Llusar Rosa , Fedin Vladimir P. , Sokolov Maxim N. 
Published: May 2015

AbstractSubstitution reactions of binuclear niobium cluster anion [Nb2S4(NCS)8]4– with different types of pyridine‐based diimine ligands have been carried out. In the case of 2,2′‐bipyridine (bipy) and its derivatives, only monosubstituted complexes [Nb2S4(NCS)6L]2– have been isolated. In the case of 1,10‐phenanthroline and 2‐(2‐pyridyl)benzimidazole (Hpbz), both mono‐ and disubstituted complexes, [Nb2S4(NCS)6L]2– and [Nb2S4(NCS)4L2], respectively, have been obtained. Crystal structures of (Et4N)2[Nb2S4(NCS)6(bipy)]·0.5bipy·0.7CH3CN and [Nb2S4(pbmz)2(NCS)4]·5DMF·0.8H2O have been determined. All compounds have been characterized by NMR, ESI mass spectrometry, IR, UV/Vis spectroscopy, and CV. TiO2 nanoparticles modified with (Et4N)2[Nb2S4(NCS)6(bipy)] show moderate photocatalytic activity in the reaction of H2 generation from water in the presence of Na2S/Na2SO3 as a sacrificial electron donor system. The linear and nonlinear optical properties of the complexes with bipyridine ligands have been studied; the complexes function as broad‐band optical limiters.
Synthesis and Characterization of Asymmetric 1,2‐Dihydroxy‐5,5′‐bitetrazole and Selected Nitrogen‐Rich Derivatives
Authors: Hafner Katherina , Klapötke Thomas M. , Schmid Philipp C. , Stierstorfer Jörg 
Published: May 2015

AbstractA selective synthesis of asymmetric 1,2′‐dihydroxy‐5,5′‐bitetrazole monohydrate (4·H2O) from inexpensive starting materials is presented. This bitetrazole derivative contains two N‐oxides at the N1 and at the N2′ position, which both increase the energetic performance. Various energetic salts, such as hydroxylammonium (5), tetraaminobitriazolium (10), and triaminotriazolotriazolium (11) were synthesized. Neutral 4 and hydroxylammonium salt 5 were compared in detail with other tetrazole mono‐ and di‐N‐oxides to gain a deeper insight into the performance increment of N‐oxides in tetrazoles. Compounds 3–5, 9, and 11 were structurally characterized by using single‐crystal X‐ray diffraction. Additionally, all new compounds were characterized by using NMR, IR and Raman spectroscopy, mass spectrometry, elemental analysis as well as differential thermal analysis (DTA) measurements. The sensitivities of the compounds toward shock, friction, and electrostatic discharge were determined. Finally, the heats of formation were calculated and several detonation parameters were computed with the EXPLO5 v. 6.01 code.
Diiron Benzenedithiolate Complexes Relevant to the [FeFe] Hydrogenase Active Site
Authors: Pandey Indresh Kumar , Mobin Shaikh M. , Deibel Naina , Sarkar Biprajit , Kaur‐Ghumaan Sandeep 
Published: May 2015

AbstractThe reactions of the precursor complex [Fe2(CO)6(μ‐bdt)] F with PPh3, PPh2Me, PPh2H have been investigated. Treatment of F with the phosphine ligands yielded both mono‐ and disubstituted complexes [Fe2(CO)5(μ‐bdt)(PPh3)] (1), [Fe2(CO)4(μ‐bdt)(PPh3)2] (2), [Fe2(CO)5(μ‐bdt)(PPh2Me)] (3), [Fe2(CO)4(μ‐bdt)(PPh2Me)2] (4), [Fe2(CO)5(μ‐bdt)(PPh2H)] (5) and [Fe2(CO)4(μ‐bdt)(PPh2H)2] (6). Crystal structures have been reported for complexes 1–3. Complexes 1, 3 and 5 participate in electrocatalytic proton reduction in the presence of two distinct acids of varying strengths: HClO4 and CF3CO2H.
Analysis and occurrence of dichloropropanol fatty acid esters and related process‐induced contaminants in edible oils and fats
Authors: Kuhlmann Jan 
Published: May 2015

A new sensitive method for the indirect determination of ester‐bound 2,3‐dichloro‐1‐propanol (2,3‐DCP), 1,3‐dichloro‐2‐propanol (1,3‐DCP), 2‐chloro‐1,3‐propanediol (2‐MCPD), 3‐chloro‐1,2‐propanediol (3‐MCPD) and 2,3‐epoxy‐1‐propanol (glycidol) in oil matrices is presented. It is based on a mild alkaline‐catalysed release of chlorohydrins and glycidol, followed by a transformation of glycidol to monobromopropanediol (MBPD) according to a modification of the AOCS Official Method Cd 29b‐13 (3‐in‐1 method). The dichloropropanols are separated from the monohalogenated diols and the oil matrix by l/l extraction and determined separately by headspace gas chromatography‐mass spectrometry (GC‐MS‐HS). Both MCPD isomers and the glycidol derivative are derivatised with phenylboronic acid (PBA) and analysed by GC‐MS separately. Method validation was performed in an oil matrix using isotopic labelled esterified standards. Linearity was verified for all analytes (r2 > 0.998). The limit of detection (LOD) for all analytes was ≤5 μg/kg. The modified determination of ester‐bound MCPD and glycidol was tested for accuracy by analysing reference samples. All free and bound analytes were investigated regarding their stability against undesired alkaline‐induced transformation. It was also demonstrated that bound MCPD and bound DCP might be generated in oil by heat treatment in the presence of a strong chloride donor. The method was applied to the analysis of a variety of different edible oils. None of the two tested dichloropropanols was detected. By contrast and as might be expected, both bound MCPD and bound glycidol were consistently detected in refined oils.Practical applications: The presented application is suitable for the parallel determination of ester‐bound dichloropropanols and monochloropropanols and ester‐bound glycidol in edible oils and fats using simple techniques for sample preparation. It covers more analytes and is more sensitive than other previously reported methods. Substitution of the double sample preparation, (a part of the AOCS Official Method Cd 29b‐13), by determining a correction factor for a whole set of samples, may reduce the effort required for sample preparation and raw data analysis. Furthermore, the investigation of basic transformations that may occur during sample preparation can be helpful for a better understanding of the complex chemistry in MCPD and glycidol analysis. Similarly, the results from heating frying fat in the presence of aluminium chloride might help to understand the distribution of chlorohydrin isomers in heat‐treated oils and fats.Assumed heat‐induced formation pathways of ester‐bound chlorohydrins in an edible oil.
Double C–H Functionalization to Construct Polycyclic Heteroarenes Catalyzed by an Ionic Salt of a Pd Complex with an N‐Heterocyclic Carbene Ligand
Authors: Ghosh Sanjay Kumar , Kuo Bing‐Chiuan , Chen Hsiang‐Yu , Li Jia‐Ying , Liu Shuang‐De , Lee Hon Man 
Published: May 2015

AbstractA new ionic salt, cis‐[Pd(L)(PPh3)(H2O)2](SO3CF3)2 (A), in which L is an amido‐functionalized N‐heterocyclic carbene (NHC) ligand, has been prepared by the salt metathesis reaction between [Pd(L)(PPh3)Cl2] and AgOTf in wet acetonitrile. It was successfully characterized by NMR spectroscopy, elemental analysis, and single‐crystal X‐ray diffraction analysis. Complex A was found to be effective in catalyzing the double C–H functionalization of various nitrogen‐ and sulfur‐containing heteroarenes to form fused polycyclic heteroaromatic compounds with alkynes in the presence of Cu(OAc)2 and tetra‐n‐butylammonium bromide. Indoles, thiophenes, imidazo[1,2‐a]pyridine, and imidazoles were used as substrates. In particular, intriguing imidazo[5,1,2‐cd]indolizine compounds could be obtained under the conditions employed.
First Application of Heterogeneous Cobalt Catalysis in Csp2–N Cross‐Coupling of Activated Chloroarenes under Ligand‐Free Conditions
Authors: Mukherjee Nirmalya , Chatterjee Tanmay , Ranu Brindaban C. 
Published: May 2015

AbstractA heterogeneous CoII/Al2O3 catalyst efficiently catalyses the N‐arylation of N‐heterocycles and open‐chain secondary amines by activated chloroarenes and chloroheteroarenes under ligand‐free conditions in water to give a series of functionalized tertiary amines. The catalyst was prepared by immobilizing CoBr2 onto the surface of Al2O3, and was characterized by X‐ray diffraction, X‐ray photoelectron spectroscopy, scanning electron microscopy, and energy‐dispersive X‐ray analysis. This catalyst could be recycled up to six times without any appreciable loss of catalytic activity.
Optimization of growth conditions toward two‐stage cultivation for lipid production of chlorella vulgaris
Authors: Liu Junying , Song Yunmeng , Liu Yuhuan , Ruan Roger 
Published: May 2015

Increasing concerns about limited fossil fuel and elevated level of atmospheric carbon dioxide are driving force to develop renewable biofuels, and microalgae are considered a particularly promising feedstock for industrialized biofuel due to their inherent advantages. It is imperative to further optimize the growth conditions in order to achieve maximal algal biomass productivity and low down the cost of microalgal biomass production. The research in this project aimed to enhance lipid production of Chlorella vulgaris by optimizing the nutrient supply and growth conditions. The effects of temperature, nitrogen concentration and initial cell density on neutral lipid productivity were evaluated and optimized by response surface method with a 17‐run Box–Behnken design (BBD). With the increase of temperature from 20 to 30°C, the neutral lipid productivity increased up to its peak value at 27°C. However, the 2D contour lines showed the temperature has a significant effect on neutral lipid productivity compared with those of cell density and/or nitrogen concentration. The optimal conditions for the algal growth are 1.5 g L−1 of nitrogen concentration and 50% of cell density at 27.4°C. The optimal lipid productivity obtained from the experiment was in agreement with the model prediction, confirming the validity of the model. © 2015 American Institute of Chemical Engineers Environ Prog, 34: 1801–1807, 2015
Temporal trends of perfluoroalkyl substances (PFAS) in eggs of coastal and offshore birds: Increasing PFAS levels associated with offshore bird species breeding on the Pacific coast of Canada and wintering near Asia
Authors: Miller Aroha , Elliott John E. , Elliott Kyle H. , Lee Sandi , Cyr Francois 
Published: May 2015

Abstract

Perfluoroalkyl substances (PFAS) such as perfluoroalkyl carboxylates (PFCAs) and perfluoroalkyl sulfonates (PFSAs) have become virtually ubiquitous throughout the environment, and, based on laboratory studies, have known toxicological consequences. Various national and international voluntary phase-outs and restrictions on these compounds have been implemented over the last 10 to 15 years. In the present study, we examine trends (1990/1991–2010/2011) in aquatic birds (ancient murrelet, Synthliboramphus antiquus [2009 only]; Leach's storm-petrels, Oceanodroma leucorhoa; rhinoceros auklets, Cerorhinca monocerata; double-crested cormorants, Phalacrocorax auritus; and great blue herons, Ardea herodias). The PFCA, PFSA, and stable isotope (δ15N and δ13C) data collected from these species from the Pacific coast of Canada, ranging over 20 to 30 years, were used to investigate temporal changes in PFAS coupled to dietary changes. Perfluorooctane sulfonic acid (PFOS), the dominant PFSA compound in all 4 species, increased and subsequently decreased in auklet and cormorant eggs in line with the manufacturing phase-out of PFOS and perfluorooctanoic acid (PFOA), but concentrations continuously increased in petrel eggs and remained largely unchanged in heron eggs. Dominant PFCA compounds varied between the offshore and coastal species, with increases seen in the offshore species and little or variable changes seen in the coastal species. Little temporal change was seen in stable isotope values, indicating that diet alone is not driving observed PFAS concentrations. Environ Toxicol Chem 2015;34:1799–1808. © 2015 SETAC
Influence of soil properties and soil leaching on the toxicity of ionic silver to plants
Authors: Langdon Kate A. , McLaughlin Mike J. , Kirby Jason K. , Merrington Graham 
Published: May 2015

Abstract

Silver (Ag) has been shown to exhibit antimicrobial properties; as a result, it is being used increasingly in a wide range of consumer products. With these uses, the likelihood that Ag may enter the environment has increased, predominately via land application of biosolids or irrigation with treated wastewater effluent. The aim of the present study was to investigate the toxicity of Ag to 2 plant species: barley (Hordeum vulgare L. CV Triumph) and tomato (Lycopersicum esculentum) in a range of soils under both leached and unleached conditions. The concentrations that resulted in a 50% reduction of plant growth (EC50) were found to vary up to 20-fold across the soils, indicating a large influence of soil type on Ag toxicity. Overall, barley root elongation was found to be the least sensitive to added Ag, with EC50 values ranging from 51 mg/kg to 1030 mg/kg, whereas the tomato plant height showed higher sensitivity with EC50 values ranging from 46 mg/kg to 486 mg/kg. The effect of leaching was more evident in the barley toxicity results, where higher concentrations of Ag were required to induce toxicity. Variations in soil organic carbon and pH were found to be primarily responsible for mitigating Ag toxicity; therefore, these properties may be used in future risk assessments for Ag to predict toxicity in a wide range of soil types. Environ Toxicol Chem 2015;34:2503–2512. © 2015 SETAC
Thermo‐mechanical Coupling Properties of Proton Exchange Membrane in Liquid Water
Authors: Shi S. , Chen G. , Chen X. 
Published: May 2015

AbstractIn this study, the effects of the combination and interaction of thermal and mechanical loading on mechanical behaviors of proton exchange membranes (PEMs) under immersed condition were investigated. Experiments under two kinds of loading path were performed: the quasi‐simultaneous loading path where mechanical loads and temperature occurred simultaneously and the rectangular loading path where thermal and mechanical loads were inserted in turn. The quasi‐simultaneous loading path is composed of in‐phase, 90° and 180° out‐of‐phase loading paths. Comparison between in‐phase and 180° out‐of‐phase loading paths showed that strain accumulation under in‐phase loading path mainly resulted from creep strain while that under 180° out‐of‐phase loading path were mostly induced by cyclic stress. Accumulation of strain was comprised of tensile strain and creep strain, and these two strain components showed different evolution trends with thermo‐mechanical cycles. In addition, the modulus of the membrane was history‐dependent as indicated from results of rectangular loading path. Through comparing creep strain with strain energy density which is an indicator of damage in the membrane, we came to the conclusion that creep strain contributed to the damage of the membrane in the first three cycles.
Don't Mind the Gap: Intuitions, Emotions, and Reasons in the Enhancement Debate
Authors: Giubilini Alberto 
Published: May 2015

AbstractReliance on intuitive and emotive responses is widespread across many areas of bioethics. The current debate on biotechnological human enhancement is particularly interesting in this respect. A strand of “bioconservatives” that has explicitly drawn connections to the modern conservative tradition, dating back to Edmund Burke, appeals to the alleged wisdom of our intuitions and emotions to ground opposition to some biotechnologies or their uses. Such reliance on intuitions and emotions is widely acknowledged as one of the distinguishing features of this conservative strand by both its supporters and opponents.So‐called bioliberals, those who in principle do not oppose human bioenhancement, tend to rely on rational arguments and to see intuitions and emotions mostly as sources of biases. This approach often translates into shifting the burden of proof onto bioconservatives and challenging them to provide arguments against the proposed enhancement to back what bioliberals perceive as merely intuitive, emotive, and irrational reactions.In this article, I am going to show that the methodological divide between bioliberals and bioconservatives is less significant than at first glance it appears to be and less significant than it is often taken to be. I will do so by defending two theses. The first is that reliance on intuitions and emotions is not a prerogative of bioconservatives: bioliberals have their typical intuitions and emotive responses and are for this reason exposed to potential biases in the same way as bioconservatives are. The second thesis is that reliance on intuitions and emotions is not necessarily antithetic to reason and rationality.
Effects of Geographical Accessibility on the Use of Outpatient Care Services: Quasi‐Experimental Evidence from Panel Count Data
Authors: Elek Péter , Váradi Balázs , Varga Márton 
Published: May 2015

AbstractIn 2010–2012, new outpatient service locations were established in Hungarian micro‐regions, which had lacked such capacities before. We exploit this quasi‐experiment to estimate the effect of geographical accessibility on outpatient case numbers using both individual‐level and semi‐aggregate panel data. We find a 24–27 per cent increase of case numbers as a result of the establishments. Our specialty‐by‐specialty estimates imply that a 1‐min reduction of travel time to the nearest outpatient unit increases case numbers for example by 0.9 per cent in internal care and 3.1 per cent in rheumatology. The size of the new outpatient capacities has a separate effect, raising the possibility of the presence of supplier‐induced demand.By combining a fixed‐effects logit and a fixed‐effects truncated Poisson estimator, we decompose the effects into increases in the probability of ever visiting a doctor on the one hand and an increase of the frequency of visits on the other hand. We find that new visits were dominant in the vast majority of specialties, whereas both margins were important for example in rheumatology. Finally, we demonstrate the usefulness of the fixed‐effects truncated Poisson estimator in modelling count data by examining its robustness by simulations. Copyright © 2015 John Wiley & Sons, Ltd.
The neuroprotective effect of a traditional herbal (kyung‐ok‐ko) on transient middle cerebral artery occlusion‐Induced ischemic rat brain
Authors: Park Sang-In , Lee Jin‐Hee , Chung Yong‐An , Park Moon‐Seo , Sunwoo Hyun , Lee Kwan‐Sung , Sunwoo Yun‐Young 
Published: May 2015

ABSTRACTKyung‐ok‐ko (KOK) has been used for the treatment of central nervous system disorders such as amnesia, dementia, and cerebral ischemia. However, the effects of KOK on transient ischemic‐induced neuronal damage are still unclear. We examined whether KOK improves functional recovery and has a neuroprotective effect on infarction volume after transient middle cerebral artery occlusion (MCAO). KOK (50, 100, and 200 mg/kg) was administered orally following reperfusion and twice per day for 14 days post‐MCAO. Infarction volume was measured using 2% 2‐3‐5 triphenylterazolium (TTC) staining at 14 days post‐MCAO and alteration in regional cerebral blood flow (rCBF) after KOK treatment was monitored. Functional improvement was evaluated using adhesive removal and treadmill tests at 1, 7, and 14 days post‐MCAO. Also, apoptotic cell death was assessed by terminal deoxynucleotidyl‐transferase mediated d‐UTP‐biotin nick end (TUNEL) in the peri‐infarction region. The protein level of inflammatory cytokines such as tumor necrosis factor‐α (TNF‐α), interleukin‐1α (IL‐1α), and interleukin‐1β (IL‐1β) was measured in the ischemic core, ischemic border zone, and contralateral hemisphere regions. The KOK‐treated group showed both reduced infarction volume and behavior tests demonstrated a significant improvement as compared to the control. Also, in the KOK‐treated group, rCBF was recovered to near normal levels. The apoptotic cells were significantly decreased as compared with the control group in the ischemic peri‐infarction area. Furthermore, the level of TNF‐α, IL‐1β, and IL‐1α was decreased. These results suggest that KOK may improve functional outcome by inhibiting inflammatory cytokines (TNF‐α, IL‐1β, and IL‐1α) in neuronal injury such as ischemic stroke.
Signal intensity correction for multichannel MR images using radon transformation
Authors: Lee Dong‐Hoon , Hong Cheolpyo , Lee Man‐Woo , Han Bong‐Soo 
Published: May 2015

ABSTRACTThe purpose of this study is to correct signal intensity at low‐field MRI system with multichannel receiver coils using Radon transformation and filtered backprojection (FBP) method. An open‐type 0.32 T MRI system and a body size phantom were used to acquire the MR images. We used various types of coils from 2‐channels to 4‐channels, which minimized the loss of signal. In the intensity correction process, Radon transform was used for the images of each channel and low‐pass filtering was applied to reduce noise. After that FBP was used for the space transform again from the Radon space to the image space. We also made changes to the projection ranges and their intervals, and then confirmed them to evaluate the optimal parameters. All the intensity corrected results were compared with its original sum‐of‐square (SOS) images, and the corrected images showed more uniform and homogeneous intensities than the images without correction. In addition, these results were also shown in the quantitative values through the signal intensity variations according to the cut view along the horizontal lines of the images. The feasibility of our approach and results for signal intensity correction may be useful and helpful for the researchers of low‐field system with multichannel coils.
Urinary Tract Stones and Osteoporosis: Findings From the Women's Health Initiative
Authors: Carbone Laura D , Hovey Kathleen M , Andrews Christopher A , Thomas Fridtjof , Sorensen Mathew D , Crandall Carolyn J , Watts Nelson B , Bethel Monique , Johnson Karen C 
Published: May 2015

ABSTRACT

Kidney and bladder stones (urinary tract stones) and osteoporosis are prevalent, serious conditions for postmenopausal women. Men with kidney stones are at increased risk of osteoporosis; however, the relationship of urinary tract stones to osteoporosis in postmenopausal women has not been established. The purpose of this study was to determine whether urinary tract stones are an independent risk factor for changes in bone mineral density (BMD) and incident fractures in women in the Women's Health Initiative (WHI). Data were obtained from 150,689 women in the Observational Study and Clinical Trials of the WHI with information on urinary tract stones status: 9856 of these women reported urinary tract stones at baseline and/or incident urinary tract stones during follow-up. Cox regression models were used to determine the association of urinary tract stones with incident fractures and linear mixed models were used to investigate the relationship of urinary tract stones with changes in BMD that occurred during WHI. Follow-up was over an average of 8 years. Models were adjusted for demographic and clinical factors, medication use, and dietary histories. In unadjusted models there was a significant association of urinary tract stones with incident total fractures (HR 1.10; 95% CI, 1.04 to 1.17). However, in covariate adjusted analyses, urinary tract stones were not significantly related to changes in BMD at any skeletal site or to incident fractures. In conclusion, urinary tract stones in postmenopausal women are not an independent risk factor for osteoporosis. © 2015 American Society for Bone and Mineral Research.