bluuebunny/crossref_metadata_2025_split huggingface dataset:
Alkali Metal, Magnesium, and Zinc Complexes of Bis(chalcogenophosphinoyl)methanide Ligands
Authors: Thirumoorthi Ramalingam , Chivers Tristram 
Published: May 2012

AbstractThe complexes [Na{HC(PPh2S)2}] (Na3a), [Na{HC(PPh2Se)2}] (Na3b), [K{HC(PPh2S)2}]∞ (K3a), [K{HC(PPh2Se)2}]∞ (K3b), [Mg{HC(PPh2S)2}2] (Mg(3a)2), [Mg{HC(PPh2Se)2}2] (Mg(3b)2), and [Zn{HC(PPh2S)2}2] [Zn(3a)2] have been prepared in good yields (69–92 %) by treatment of the neutral ligands H2C(PPh2E)2 (1a, E = S; 1b, E = Se) with [Na{N(SiMe3)2}] (Na3a), NaNH2 (Na3b), [K{N(SiMe3)2}] (K3a and K3b), [Mg{N(SiMe3)2}2] [Mg(3a)2 and Mg(3b)2], or Me2Zn [Zn(3a)2] as base in THF/toluene. These compounds were characterized in solution by multinuclear (1H, 13C, 31P, and 77Se) NMR spectroscopy and the X‐ray structures of K3a, K3b, Mg(3a)2, Mg(3b)2, and Zn(3a)2 were determined. In the solid state, the E,E′‐chelated ligands in K3a and K3b also engage in potassium–chalcogen interactions with adjacent molecules to form one‐dimensional ladder structures. With K3a, both sulfur atoms of the ligand are involved in chelation leading to four‐membered K2S2 rings, whereas only one selenium atom is tricoordinated in K3b; significant potassium···aryl interactions are also observed in both structures. In the homoleptic magnesium complexes Mg(3a)2 and Mg(3b)2, the E,E′ chelation by the methanide ligands is supplemented by weak, unequal Mg···C interactions [2.781(10) and 3.199(7) Å for Mg(3a)2; 3.331(8) and 3.217(7) Å for Mg(3b)2]. The zinc complex Zn(3a)2 is isostructural with the previously reported selenium analogue Zn(3b)2. The X‐ray structures of the S,S′‐chelated complex [(TMEDA)Li3a] as well as new polymorphs of 1a and 1b are also reported.
Cholesterol oxidation products in milk: Processing formation and determination
Authors: Calderón‐Santiago Mónica , Peralbo‐Molina Ángela , Priego‐Capote Feliciano , Luque de Castro María Dolores 
Published: May 2012

AbstractCholesterol oxidation products (oxysterols) are commonly present in foods derived from animals. The main limitations for analysis of these products are associated with the long sample preparation protocols that require saponification. In this research, a protocol was optimized for determination of oxysterols in milks under the process to obtain given commercial milk products. UHT milks, powder milks, condensed milk, and evaporated milk were selected for this study. The levels of the different oxysterols are discussed attending to the type of milk. UHT and skimmed powder milks provide the highest concentration of oxysterols. Particularly, high concentrations were found for 7β‐hydroxy‐cholesterol (up to 205.6 ng/mL), 5‐cholesten‐3β‐ol‐7‐one (up to 21.8 ng/mL), cholesterol 5α,6α‐epoxide (up to 14.9 ng/mL), and 25‐hydroxycholesterol (up to 5.1 ng/mL). An increase in cholesten‐3β‐ol‐7‐one and cholesterol 5α,6α‐epoxide, resulting from the skimming process, was also observed. Additionally, two different heating modes, microwave‐assisted and conventional heating, have been mimicked to study their influence on the formation of oxysterols in milk. Both heating protocols contributed to the formation of oxysterols but short periods of microwave irradiation (60 s) can lead to levels of oxysterols similar to conventional heating for 5 min.Practical applications: The results of the research described in this article, supported by previous studies in the field, allow to advice about the strong influence of microwave heating of milk on the formation of toxic oxides from the lipid fraction. Although conventional heating can be more tedious and time consuming, it seems to be healthier.
DABCO‐Mediated [4+2] Annulation of But‐3‐yn‐2‐one and Activated Ketones: Facile Preparation of 2,3‐Dihydropyran‐4‐one
Authors: Lian Zhong , Zhao Qian‐Yi , Wei Yin , Shi Min 
Published: May 2012

AbstractWe found that nitrogen‐containing Lewis base mediated [4+2] annulation of but‐3‐yn‐2‐one with activated ketones could proceed efficiently to give the corresponding 2,3‐dihydropyran‐4‐ones in moderate to good yields under mild conditions. The substrate scope has been carefully examined. Moreover, a plausible reaction mechanism for the [4+2] annulation of but‐3‐yn‐2‐one with activated ketones mediated by DABCO has been proposed on the basis of previous literature and our own investigations.
Microwave‐Assisted Synthesis of Guanidine Organocatalysts Bearing a Tetrahydroisoquinoline Framework and Their Evaluation in Michael Addition Reactions
Authors: Naicker Tricia , Arvidsson Per I. , Kruger Hendrik G. , Maguire Glenn E. M. , Govender Thavendran 
Published: May 2012

AbstractThe simple and practical syntheses of chiral guanidine organocatalysts and their evaluation in the asymmetric Michael addition reaction of malonates and β‐keto esters with nitro‐olefins is reported. These organocatalysts are the first of their kind based on a tetrahydroisoquinoline framework. In addition, a microwave‐assisted procedure for introducing the guanidine unit onto amino amide derivatives is reported. The chiral products were obtained with quantitative chemical efficiency (up to 99 % yield) and excellent enantioselectivity (up to 97 % ee).
Deleterious effects of neuronal accumulation of glycogen in flies and mice
Authors: Duran Jordi , Tevy María Florencia , Garcia‐Rocha Mar , Calbó Joaquim , Milán Marco , Guinovart Joan J. 
Published: May 2012

AbstractUnder physiological conditions, most neurons keep glycogen synthase (GS) in an inactive form and do not show detectable levels of glycogen. Nevertheless, aberrant glycogen accumulation in neurons is a hallmark of patients suffering from Lafora disease or other polyglucosan disorders. Although these diseases are associated with mutations in genes involved in glycogen metabolism, the role of glycogen accumulation remains elusive. Here, we generated mouse and fly models expressing an active form of GS to force neuronal accumulation of glycogen. We present evidence that the progressive accumulation of glycogen in mouse and Drosophila neurons leads to neuronal loss, locomotion defects and reduced lifespan. Our results highlight glycogen accumulation in neurons as a direct cause of neurodegeneration.
Bone Mass Eight Years After Treatment for Adolescent‐Onset Anorexia Nervosa
Authors: Halvorsen Inger , Platou Dagmar , Høiseth Arne 
Published: May 2012

AbstractObjectiveThis paper aims to study long‐term bone mineral development in former patients with an onset of anorexia nervosa during childhood and adolescence.MethodsBone mineral density (BMD) in lumbar spine and total hip was measured in 39 female participants (mean age = 23.1 years, SD 3.5) an average of 8.1 (±3.3) years after treatment start.ResultsAt follow‐up, seven participants (17.9%) still suffered from an eating disorder. Mean BMD in the former patients was within the normal range in the hip but significantly reduced in the spine. Fourteen (36%) of the participants had osteopenia, and three (8%) had osteoporosis in the spine and/or hip. Amenorrhea for more than two years was associated with reduced BMD in the spine, whereas low weight at follow‐up was associated with low BMD in both the spine and the hip.ConclusionA large minority of these former patients had low bone mass in young adulthood. In accordance with other studies, our findings support the importance of weight restoration for future bone health in young patients with anorexia nervosa. Copyright © 2012 John Wiley & Sons, Ltd and Eating Disorders Association.
Toxicity of dietary methylmercury to fish: Derivation of ecologically meaningful threshold concentrations
Authors: Depew David C. , Basu Niladri , Burgess Neil M. , Campbell Linda M. , Devlin Ed W. , Drevnick Paul E. , Hammerschmidt Chad R. , Murphy Cheryl A. , Sandheinrich Mark B. , Wiener James G. 
Published: May 2012

Abstract
Threshold concentrations associated with adverse effects of dietary exposure to methylmercury (MeHg) were derived from published results of laboratory studies on a variety of fish species. Adverse effects related to mortality were uncommon, whereas adverse effects related to growth occurred only at dietary MeHg concentrations exceeding 2.5 µg g−1 wet weight. Adverse effects on behavior of fish had a wide range of effective dietary concentrations, but generally occurred above 0.5 µg g−1 wet weight. In contrast, effects on reproduction and other subclinical endpoints occurred at dietary concentrations that were much lower (&lt;0.2 µg g−1 wet wt). Field studies generally lack information on dietary MeHg exposure, yet available data indicate that comparable adverse effects have been observed in wild fish in environments corresponding to high and low MeHg contamination of food webs and are in agreement with the threshold concentrations derived here from laboratory studies. These thresholds indicate that while differences in species sensitivity to MeHg exposure appear considerable, chronic dietary exposure to low concentrations of MeHg may have significant adverse effects on wild fish populations but remain little studied compared to concentrations in mammals or birds. Environ. Toxicol. Chem. 2012; 31: 1536–1547. © 2012 SETAC
Pyrethroid and organophosphate pesticide-associated toxicity in two coastal watersheds (California, USA)
Authors: Phillips Bryn M. , Anderson Brian S. , Hunt John W. , Siegler Katie , Voorhees Jennifer P. , Tjeerdema Ron S. , McNeill Katie 
Published: May 2012

Abstract
Portions of the Santa Maria River and Oso Flaco Creek watersheds in central California, USA, are listed as impaired under section 303(d) of the Clean Water Act and require development of total maximum daily load (TMDL) allocations. These listings are for general pesticide contamination, but are largely based on historic monitoring of sediment and fish tissue samples that showed contamination by organochlorine pesticides. Recent studies have shown that toxicity in these watersheds is caused by organophosphate pesticides (water and sediment) and pyrethroid pesticides (sediment). The present study was designed to provide information on the temporal and spatial variability of toxicity associated with these pesticides to better inform the TMDL process. Ten stations were sampled in four study areas, one with urban influences, and the remaining in agriculture production areas. Water toxicity was assessed with the water flea Ceriodaphnia dubia, and sediment toxicity was assessed with the amphipod Hyalella azteca. Stations in the lower Santa Maria River had the highest incidence of toxicity, followed by stations influenced by urban inputs. Toxicity identification evaluations and chemical analysis demonstrated that the majority of the observed water toxicity was attributed to organophosphate pesticides, particularly chlorpyrifos, and that sediment toxicity was caused by mixtures of pyrethroid pesticides. The results demonstrate that both agriculture and urban land uses are contributing toxic concentrations of these pesticides to adjacent watersheds, and regional water quality regulators are now using this information to develop management objectives. Environ. Toxicol. Chem. 2012; 31: 1595–1603. © 2012 SETAC
Enhanced closed‐loop EOSTBC schemes for multiple transmit antennas
Authors: Zhang Peng , Yuan Dongfeng , Zhang Haixia , Zhou Xiaotian 
Published: May 2012

ABSTRACTIn this paper, a novel closed‐loop multiple antennas transmission scheme suitable for M = 2p(p ⩾2) transmit antennas is proposed on the basis of the extended orthogonal space–time block codes. And, all 2p transmit antennas are divided into p groups, and each group includes two antennas, and Alamouti orthogonal space‐time block code is adopted. All p groups are used to transmit the same source symbols, and each group is scaled by one scale matrix before transmission. The elegantly designed scale matrix takes both power allocation and phase rotation into account to optimise the antenna array gain and exploit full transmit diversity while maintaining low linear decoding complexity provided by Alamouti code. By formulating the problem as a convex optimisation problem, the optimal solution for the scale matrix is achieved. In addition, several practical feedback codebook design methods are proposed, and their advantages over the existing closed‐loop extended orthogonal space–time block code schemes are clearly demonstrated by both analysis and simulation results. Copyright © 2012 John Wiley & Sons, Ltd.
Asymptotic optimal detection for MIMO communication systems employing tree search with incremental channel partition preprocessing
Authors: Radji Djelili , Leib Harry 
Published: May 2012

ABSTRACTThe high complexity of optimal detection for spatial multplexing multiple‐input multiple‐output systems motivates the need for more practical alternatives. Among many suboptimal schemes reported in the literature, very few can be proven to provide close to optimal performance with low fixed complexity. The recently introduced Selection based Minimum Mean Square Error Ordered Successive Interference Cancellation (Sel‐MMSE‐OSIC) algorithm is one such scheme that employs list‐based detection. Simulations results showed that its performance is nearly indistinguishable from optimal at almost all signal‐to‐noise ratio (SNR) levels. In this paper, we propose an improved asymptotically optimal fixed‐complexity algorithm that provides substantial complexity reductions over Sel‐MMSE‐OSIC with similar error rate performance. This scheme is based on simplified channel partition and efficient tree‐based list detection. To achieve further reductions in complexity for large constellation sizes, a variable complexity version of this scheme is proposed. The resulting algorithm is a variable complexity scheme that operates on a very small subset of candidates and employs an improved channel partition preprocessing that not only reduces complexity but also guarantees high SNR optimality over space uncorrelated channels. Simulations results confirm that the proposed scheme provides significant complexity reductions over conventional variable complexity detection schemes. Copyright © 2012 John Wiley & Sons, Ltd.
Structure and reactivity of thiosulfonic acids and their anions: A theoretical study
Authors: Cypryk Marek , Krasiński Grzegorz , Mikołajczyk Marian 
Published: May 2012

AbstractThe structures and properties of thiosulfonic acids, RS(SO2)H, R = H (1), Me (2), t‐Bu, (3), Vi (4), Allyl (5), Ph (6), F (7), Cl (8), Br (9), and CF3 (10)) and their anions have been investigated theoretically by the density functional methods. The calculations show that the thiolo‐tautomers, RS(O)2SH, are by 6–8 kcal/mol lower in Gibbs free energy than the thiono‐tautomers, RS(O)(S)OH in the gas phase. In water, the energy difference between tautomers is reduced to about 2–3 kcal/mol, due to more effective solvation of the thiono forms. Thiono–thiolo isomerization may proceed either intra‐ or intermolecularly. The water molecule participating in intramolecular transfer significantly lowers the energy barrier. The thiosulfonate anions show the ambident character with the negative charge dispersed over terminal O and S atoms and are stabilized by electronegative substituents. A study of nucleophilicity of thiosulfonate anions toward MeBr as well as MeO(S)(O)SH and MeS(O)2SH electrophiles measured as the barriers of SN2 substitutions reveals that terminal S(‐) is a stronger nucleophile than O(‐). It is also softer in terms of the Fukui function. © 2012 Wiley Periodicals, Inc. Heteroatom Chem 23:329–339, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.21021
Provision of health care services in austria. A time series approach
Authors: Radosch Ulrike 
Published: May 2012

AbstractThe presented article describes the investigation of three main variables of the health care system in Austria by applying time series analysis. The quantities under consideration are the stock of physicians working in the ambulatory sector, the number of medical services provided and the related costs. The article discusses non‐stationarity and unit root tests and presents an outlook for the considered variables. One conclusion to be drawn from the presented analysis is the presence of a stochastic element in the analyzed variables.
From private club to professional network: An economic history of the Health Economists' Study Group, 1972–1997
Authors: Croxson Bronwyn 
Published: May 2012

AbstractHESG was founded in 1972 as part of a conscious effort to establish health economics as an identifiable sub‐discipline. It is debatable whether the growth of health economics was demand‐led or supplier‐driven, but in either case the existence of a HESG played a vital role. HESG was founded as a private club, in the tradition of English gentlemen's clubs, designed to provide a forum for debate and an invisible, supportive faculty for health economists dispersed between different organisations throughout the UK. It was given impetus by public economists at the University of York, who were effectively academic entrepreneurs, motivated in part by private gain, but by their actions overcoming the free‐rider problem that might otherwise have retarded the development of health economics. Over the course of its first 25 years, HESG has changed and its membership has grown and altered in composition ‐ over this period, HESG has evolved from a private club to a professional network. It has made a vital contribution to the existence and form of health economics as a subdiscipline in the United Kingdom, and has in turn itself been influenced by the subdiscipline. As a subdiscipline, UK health economics in the 1990s generally draws on a small body of economic theory and is practised by a distinct, identifiable group of economists. This paper was commissioned by HESG, as a history of the organisation. It also analyses the foundation and evolution of HESG as an institutional arrangement designed to overcome a collective action problem.
The impact of health economics on health policy in England, and the impact of health policy on health economics, 1972–1997
Authors: Hurst Jeremy 
Published: May 2012

AbstractThis paper contains a review of the impact of health economics on health policy in England during the past 25 years. Some health economists have expressed disappointment with the scale of the impact that health economics has had on policy but the record set out below suggests that there is modest cause for celebration. That is not to say that there is cause for complacency. There is still a long way to go before all important health policies are based on sound economics reasoning and evidence.The paper begins with some definitions and background; it covers nine areas of health policy, and health policy making, where past impacts of health economics have been postulated; it covers briefly the reciprocal impact of health policy on health economics; and it concludes with a discussion about the findings.
Smart‐Home Interface Design: Layout Organization Adapted to Americans' and Koreans' Cognitive Styles
Authors: Jeong Kyeong‐Ah , Proctor Robert W. , Salvendy Gavriel 
Published: May 2012

AbstractIncreases in the number of household appliances and devices with RFID tags have created a need for efficient organization of smart‐home interfaces in consideration of residents. Previous studies of information‐grouping and cultural‐differences in cognitive style on performance have yielded mixed results. Gender has not typically been considered, nor have subjective preferences been measured. We tested four participant groups (American and Korean males and females) and two interface groupings (functional and spatial). Participants performed tasks that required locating controls for specific devices/functions, after which they rated the interfaces on several scales. American males preferred the functional organization, but Koreans and American females tended to prefer the spatial organization. The results are consistent with Koreans' preference for thematic‐structure and the view that men's and women's cognitive styles differ in masculine/individualistic cultures (U.S.) but not in feminine/collectivistic cultures (Korea). Potential applications include physical (e.g., power and wall‐mounted switches) and virtual interactions (e.g., remote controls, GUI/Web/Phone). © 2012 Wiley Periodicals, Inc.
Analysis of Frequency, Intensity, and Interference of Discomfort in Computerized Numeric Control Machine Operations
Authors: Muthukumar Krishnamoorthy , Sankaranarayanasamy Krishnasamy , Ganguli Anindya Kumar 
Published: May 2012

AbstractThe introduction of Computerized Numeric Control (CNC) technology in manufacturing industries revolutionized the production process a few decades back. There are some health and safety problems associated with these machine operations, however. The main objectives of the present work is to study the health and safety issues associated with the CNC machines with respect to control and display, specifically to determine the frequency, intensity of discomfort, and its interference in operating different CNC machines as reported by the workers operating them. The postural discomfort associated with CNC machines was studied, and the frequency, intensity of discomfort, and interference of the level of discomfort with the participants' ability to work were recorded and analyzed. The study revealed that 20.5% of the operators reported discomfort 1 or 2 times, 25.4% experienced discomfort 3 to 4 times in a week, 37.7% had discomfort daily, and 16.4% reported discomfort several times a day. Discomfort was reported in all the body parts involved (lower back, neck, upper back, shoulder, and leg), but the highest discomfort scores were associated with the shoulder and arm region. Workers reporting discomfort several times a day also reported high mean discomfort scores. The study established that the frequency and intensity of the discomfort in all body parts is related to the position of the control panel and display. © 2012 Wiley Periodicals, Inc.
ISO 9001 and the Quality of Working Life: An Empirical Study in a Peripheral Service Industry to the Standard's Home Market
Authors: Heras‐Saizarbitoria Iñaki , Cilleruelo Ernesto , Allur Erlantz 
Published: May 2012

AbstractIn recent years, the implementation of quality management systems based on ISO 9001 has clearly gone beyond the traditional industrial and service subsectors. It has started to have a growing influence on some peripheral subsectors to the standard home market, such as those of health and social services. In this article, the influence of the main global management meta‐standard is analyzed from a macroergonomic perspective in one of the aforementioned sectors. Based on an empirical exploratory study carried out in two Spanish organizations belonging to the subsector of residential care homes for elderly persons, the influence of the adoption of the standard is analyzed, focusing on the quality of working life of the direct attention employees. © 2012 Wiley Periodicals, Inc.