bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Neutral Ion Aggregate Formation on the Electrical Conductivity of an Ionic Liquid and its Mixtures with Chloroform
Authors: Köddermann Thorsten , Klembt Sandra , Klasen Dagmar , Paschek Dietmar , Kragl Udo , Ludwig Ralf
Published: March 2012

We have studied the electrical conductivity of mixtures of the ionic liquid (IL) [C2mim][NTf2] with chloroform for various concentrations at a temperature of 303 K by both experiments and MD simulations. The molar conductivities exhibit an initial increase with decreasing IL concentration, which again sharply decreases in the region of highly diluted IL concentrations. This behavior is according to a competition between 1) the decreasing viscosity with increasing chloroform concentration due to fluidizing the mixture, and 2) the decreasing amount of charge carriers due to the formation of neutral IL aggregates. The simulated molar conductivities and their concentration dependence are found to be in reasonable agreement with the experimentally determined values, suggesting that essential correlations between the solvated ionic species in the solution are well represented. Both experiments and simulations show that the Nernst–Einstein relation drastically overestimates the conductivity of the solutions at low IL concentrations. According to our MD simulation data, this observation is due to the extensive formation of neutral aggregates in the low‐concentration regime.
Orientational Ordering of Ionic Liquids near a Charged Mica Surface
Authors: Singh Payal Rajdeep , Balasubramanian Sundaram
Published: March 2012

The self‐assembly of ions in room‐temperature ionic liquids adsorbed on a mica surface is studied using molecular dynamics simulations. Four liquids from the 1‐methyl,n‐alkylimidazolium bis(trifluoromethylsulfonyl)imide ([Cnmim][NTf2]) family are investigated, where n ranges between 2 and 8. Cations with ethyl or butyl groups are found to orient with the hydrocarbon tails lying parallel to the surface, while the hexyl and octyl tails of cations are observed to be oriented perpendicular to it. The crossover in the orientational preference matches recent observations of surface forces of these liquids.
The Influence of Defects on Mo‐Doped TiO2 by First‐Principles Studies
Authors: Yu Xiaohui , Hou Tingjun , Sun Xuhui , Li Youyong
Published: March 2012

TiO2 doped with transition metals shows improved photocatalytic efficiency. Herein the electronic and optical properties of Mo‐doped TiO2 with defects are investigated by DFT calculations. For both rutile and anatase phases of TiO2, the bandgap decreases continuously with increasing Mo doping level. The 4d electrons of Mo introduce localized states into the forbidden band of TiO2, and this shifts the absorption edge into the visible‐light region and enhances the photocatalytic activity. Since defects are universally distributed in TiO2 or doped TiO2, the effect of oxygen deficiency due to oxygen vacancies or interstitial Mo atoms is systemically studied. Oxygen vacancies associated with the Mo dopant atoms or interstitial Mo will reduce the spin polarization and magnetic moment of Mo‐doped TiO2. Moreover, oxygen deficiency has a negative impact on the improved photocatalytic activity of Mo‐doped TiO2. The current results indicate that substitutional Mo, interstitial Mo, and oxygen vacancy have different impacts on the electronic/optical properties of TiO2 and are suited to different applications.
Preparation of [Al(hfip)4]−‐Based Ionic Liquids with Siloxane‐Functionalized Cations and Their Physical Properties in Comparison with Their [Tf2N]− Analogues
Authors: Bulut Safak , Ab Rani M. A. , Welton Tom , Lickiss Paul D. , Krossing Ingo
Published: March 2012

Two new ionic liquids (ILs) with siloxane‐functionalized cations and the weakly coordinating tetraalkoxyaluminate [Al(hfip)4]− (hfip=hexafluoroisopropoxy) are prepared and characterized by nuclear magnetic resonance (NMR), infrared (IR) and Raman spectroscopy. With melting points below 0 °C they qualify as room temperature ILs (RTILs). Their temperature‐dependent viscosities and conductivities, together with those of two [Tf2N]− ILs with the same cations and a further siloxane‐functionalized [Tf2N]− IL, are measured between 0 and 80 °C, and all are described by the Vogel–Fulcher–Tammann (VFT) equations. We note that the [Al(hfip)4]− ILs have lower viscosities than their [Tf2N]− analogues at all measured temperatures and higher conductivities at room temperature.
Theoretical Investigation on SERS of Pyridine Adsorbed on Cn Clusters Induced by Charge Transfer: A Hint that SERS Could be Applied on Many Materials
Authors: Kong Xiangkai , Chen Qianwang , Li Ran , Cheng Kai , Yan Nan , Chen Jian , Zhou Yumei
Published: March 2012

The SERS spectra of pyridine–Cn (n=1–6) complexes are investigated theoretically. The obtained enhancement factors of about 102–103 in the pre‐resonance Raman spectrum calculations are attributed to charge‐transfer transitions from the carbon clusters to pyridine, where a good match of band structures between substrates and probe molecules is essential.
Synthesis of flower‐like zinc oxide and polyaniline with worm‐like morphology and their applications in hybrid solar cells
Authors: Mavundla S. E. , Malgas G. F. , Motaung D. E. , Iwuoha E. I.
Published: March 2012

ZnO with a “flower‐like” morphology was synthesized using a simple microwave assisted hydrothermal method and used as an acceptor material in hybrid solar cells. X‐Ray diffraction and Raman Spectroscopy confirmed the formation of a highly crystalline wurtzite ZnO structure. A highly crystalline and conductive polyaniline with “worm‐like” morphology was synthesized by chemical polymerization of aniline using KH(IO3)2 as an oxidant and was used as a donor material for solar cells. The morphology was probed by using scanning and transmission electron microscopy. Polyaniline with worm‐like morphology had a diameter of 160 nm and about 2 µm long. Solar cell device fabricated from PANI/ZnO active bilayer demonstrated a fill factor of about 22.8%. Upon blending PANI with ZnO the fill factor was improved to 25.6% and efficiency by almost 100 fold when PANI:ZnO 1:1 composite was used as an bulk heterogeneous active layer. The fill factor was further improved to 26.4% when device architecture was changed to diffused bilayer. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis by precipitation method and investigation of SnO2 nanoparticles
Authors: Nejati K.
Published: March 2012

In this paper the synthesis of SnO2 nanoparticles with average particle size up to about 70 nm using SnCl22H2O and NH4OH in 1‐botanol solution by the precipitation method is reported and the inhibition of sodium dodecyl sulphate (SDS) on the SnO2 particle growth is investigated by soaking SnO2precursor in the SDS solution for 24 h. The as‐prepared SnO2and SDS modified‐SnO2 powders, then, were calcined at different temperatures and the X‐ray powder diffraction (XRD) and Fourier transform infrared spectroscopy (FT‐IR) were used to characterize the output samples. The XRD results reveal that the structure of tin‐dioxide is tetragonal rutile and the as‐prepared SnO2 nanoparticles grow with increasing the annealing temperature, while the SDS treatment prevents the particle growth under the same condition. Furthermore, the FT‐IR results indicate the formation of tin‐hydroxyl group which are then converted into tin‐dioxide with heat treatment. Further characterization of the samples by the transmission electron microscopy (TEM) and the photoluminescence (PL) spectroscopy was carried out. The room temperature PL spectra of SnO2exhibits broad and strong peak attributed to the surface defects such as oxygen vacancies and intensity of which decreases with the increase in particle size. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In search for cross‐reactivity to immunophenotype equine mesenchymal stromal cells by multicolor flow cytometry
Authors: De Schauwer Catharina , Piepers Sofie , Van de Walle Gerlinde R. , Demeyere Kristel , Hoogewijs Maarten K. , Govaere Jan L. J. , Braeckmans Kevin , Van Soom Ann , Meyer Evelyne
Published: March 2012

During recent years, cell‐based therapies using mesenchymal stem cells (MSC) are reported in equine veterinary medicine with increasing frequency. In most cases, the isolation and in vitro differentiation of equine MSC are described, but their proper immunophenotypic characterization is rarely performed. The lack of a single marker specific for MSC and the limited availability of monoclonal antibodies (mAbs) for equine MSC in particular, strongly hamper this research. In this study, 30 commercial mAbs were screened with flow cytometry for recognizing equine epitopes using the appropriate positive controls to confirm their specificity. Cross‐reactivity was found and confirmed by confocal microscopy for CD45, CD73, CD79α, CD90, CD105, MHC‐II, a monocyte marker, and two clones tested for CD29 and CD44. Unfortunately, none of the evaluated CD34 clones recognized the equine epitopes on positive control endothelial cells. Subsequently, umbilical cord blood‐derived undifferentiated equine MSC of the fourth passage of six horses were characterized using multicolor flow cytometry based on the selected nine‐marker panel of both cell surface antigens and intracytoplasmatic proteins. In addition, appropriate positive and negative controls were included, and the viable single cell population was analyzed by excluding dead cells using 7‐aminoactinomycin D. Isolated equine MSC of the fourth passage were found to be CD29, CD44, CD90 positive and CD45, CD79α, MHC‐II, and a monocyte marker negative. A variable expression was found for CD73 and CD105. Successful differentiation towards the osteogenic, chondrogenic, and adipogenic lineage was used as additional validation. We suggest that this selected nine‐marker panel can be used for the adequate immunophenotyping of equine MSC. © 2012 International Society for Advancement of Cytometry
How many therapists? Practical guidance on investigating therapist effects in randomized controlled trials for eating disorders
Authors: Thompson Doug , Cachelin Fary , Striegel‐Moore Ruth H. , Barton Bruce , Shea Munyi , Wilson G. Terence
Published: March 2012

Objective:

An important question in implementation/dissemination research is whether the efficacy of a given treatment varies in part based on the therapist delivering the treatment. This study sought to provide practical guidance to researchers in the field of eating disorders for building measurement of therapist effects into the design of a typical, relatively small randomized controlled trial (RCT).

Method:

Using assumptions based on past trials of eating disorder treatments, Monte Carlo simulations were used to examine 12 different scenarios based on crossing the number of therapists (between two and five) and the estimated therapist effect size (small, medium, and large). Patient sample size and study design were held constant.

Results:

There was reasonable power (≥70%) to detect the therapist effect with three or four therapists and a large effect size.

Discussion:

Several practical implications for testing therapist effects in RCT are discussed. © 2012 by Wiley Periodicals, Inc. Int J Eat Disord 2012.
The impact of relationships on the association between sexual orientation and disordered eating in men
Authors: Brown Tiffany A. , Keel Pamela K.
Published: March 2012

Objective:

Robust evidence supports that bisexual and gay (BG) men have increased eating pathology compared to heterosexual men. BG men may be at greater risk due to pressure to attract a male partner; however, the related implication that relationships serve as protective factors for BG men remains untested.

Method:

BG (n = 42) and heterosexual men (n = 536) completed surveys to determine whether relationship status and satisfaction moderate sexual orientation's effect on disordered eating.

Results:

Single BG men had increased restrictive disordered eating compared to single heterosexual men, while few differences were found between BG and heterosexual men in relationships. Relationship satisfaction was not related to restrictive disordered eating; however, low relationship satisfaction was associated with increased bulimic symptomatology in BG men compared to heterosexual men.

Discussion:

Being in a relationship, independent of whether or not the relationship is satisfying, may be a protective factor for restrictive disordered eating in BG men. © 2012 by Wiley Periodicals, Inc. (Int J Eat Disord 2012; 45:792–799)
Aryl Grignard Reagents in Chemodivergent N‐ and C‐Arylations: Concise Access to Two Families of Tetracyclic Fused Carbazoles from 6‐Nitroquinolines
Authors: Sánchez Juan Domingo , Egris Riccardo , Perumal Subbu , Villacampa Mercedes , Menéndez J. Carlos
Published: March 2012

The reaction between aryl Grignard compounds and 5‐methoxy‐6‐nitroquinoline derivatives in THF was found to proceed in a chemodivergent mode that depended on the functional groups present in the heterocyclic ring. Thus, the reactions that started from carbostyril derivatives afforded 6‐(arylamino)carbostyrils as the major products, whereas those that started with 2‐alkoxyquinolines gave exclusively 5‐arylquinolines. Both types of products were transformed into tetracyclic fused linear or angular carbazole systems by using palladium‐promoted oxidative coupling or Cadogan reactions, respectively. In the course of this work, an unprecedented oxidative demethylation by palladium acetate of 1,4‐dimethoxybenzene systems to the corresponding quinones was discovered.
Microwave‐Assisted Domino Benzannulation of α‐Oxo Ketenes: Preparation of 1,3‐Dihydro‐2H‐1,5‐benzodiazepin‐2‐ones
Authors: Castillo Juan‐Carlos , Presset Marc , Abonia Rodrigo , Coquerel Yoann , Rodriguez Jean
Published: March 2012

The microwave irradiation of a series of 2‐diazo‐1,3‐diketones in the presence of an o‐phenylenediamine derivative triggered a domino Wolff rearrangement/nucleophilic addition/intramolecular imination sequence to provide a new synthetic entry to 1,3‐dihydr‐2H‐1,5‐benzodiazepin‐2‐ones, a class of molecules with important biological properties.
Probabilistic seismic hazard analysis for spatially distributed infrastructure
Authors: Han Yeliang , Davidson Rachel A.
Published: March 2012

Two key issues distinguish probabilistic seismic risk analysis of a lifeline or portfolio of structures from that of a single structure. Regional analysis must consider the correlation among lifeline components or structures in the portfolio, and the larger scope makes it much more computationally demanding. In this paper, we systematically identify and compare alternative methods for regional hazard analysis that can be used as the first part of a computationally efficient regional probabilistic seismic risk analysis that properly considers spatial correlation. Specifically, each method results in a set of probabilistic ground motion maps with associated hazard‐consistent annual occurrence probabilities that together represent the regional hazard. The methods are compared according to how replicable and computationally tractable they are and the extent to which the resulting maps are physically realistic, consistent with the regional hazard and regional spatial correlation, and few in number. On the basis of a conceptual comparison and an empirical comparison for Los Angeles, we recommend a combination of simulation and optimization approaches: (i) Monte Carlo simulation with importance sampling of the earthquake magnitudes to generate a set of probabilistic earthquake scenarios (defined by source and magnitude); (ii) the optimization‐based probabilistic scenario method, a mixed‐integer linear program, to reduce the size of that set; (iii) Monte Carlo simulation to generate a set of probabilistic ground motion maps, varying the number of maps sampled from each earthquake scenario so as to minimize the sampling variance; and (iv) the optimization‐based probabilistic scenario again to reduce the set of probabilistic ground motion maps. Copyright © 2012 John Wiley & Sons, Ltd.
Fluvial response to climatic and anthropogenic forcing in the Moselle drainage basin (NE France) during historical periods: evidence from OSL dating
Authors: Cordier Stéphane , Lauer Tobias , Harmand Dominique , Frechen Manfred , Brkojewitch Gaël
Published: March 2012

The aim of this paper is to study a low energy fluvial system response to natural and anthropogenic forcing during the last two millennia. In contrast with longer timescales (Holocene to Quaternary), historical sedimentary archives are sparse in such systems which are typically characterized by the predominance of erosion compared with aggradation. We studied three main sections in the Moselle valley (northeastern France) by a multi‐proxy approach combining morphology, sedimentology, archaeological evidence, historical archives, and dating. The geochronological framework was based on Optically Stimulated Luminescence (OSL) and validated by independent age control. The exposed sediments were allocated to different historical periods from Roman period to present. The first results show that, in contrast with many other fluvial systems, the Moselle and its tributaries did not experience major changes during historical periods. Climatic changes such as the Little Ice Age had a minor influence on floodplain aggradation (e.g. in grain size or sedimentation rates) in the Moselle valley and were only able to affect the fluvial style. This provides evidence that the reworking of sediments is the main fluvial process at short timescales in the valley floors of the Moselle catchment. In contrast, anthropogenic forcing seems important not only during recent centuries but also since Roman times. This is suggested by the case‐study of the Metz‐Mazelle section where significant headward erosion and sedimentation were recognized, and may be related to human occupation. The results therefore point to a need for increasing geoarchaeological and geochronological research in the Moselle catchment and similar low energy fluvial systems. Such research is actually essential to improve the knowledge of the fluvial response to environmental changes during the historical periods and to recognize the respective influence of natural variability and human forcing. Copyright © 2012 John Wiley & Sons, Ltd.
When one must go: The Canadian experience with strategic review and judging program value
Authors: Dumaine François
Published: March 2012

This chapter reviews the Canadian experiment with assessing the worth of public programs and policies and using the resulting value judgments to drive funding decisions. The author provides a brief overview of the Canadian Strategic Review initiative, and considers implications of this federal government approach to valuation. The author argues that never before has the evaluation function within the federal government been so directly linked to an expenditure management system that requires such a definitive valuation of programs and initiatives. The author concludes that for the evaluation function to meet expectations and maintain its fundamental purpose of being a participatory process to assist program managers in learning and improving their programs, some fine‐tuning will be necessary. © Wiley Periodicals, Inc., and the American Evaluation Association.
Evaluators in a world of valuators
Authors: Grob George F.
Published: March 2012

The author argues that in public policy making, evaluators have no monopoly on valuation, and that public policy decisions in the United States are almost never made by a single person, organizational entity, or profession. The argument is that what distinguishes evaluators from other valuators is a desire to evaluate public programs, hoping that they can find out what works and what doesn't, and then persuade policy makers, program managers, and professional advocates, and a broad citizen readership, to make rational and efficacious decisions. It is evaluators' broad command of valuation theories and practical methods, their independence, and their professional demeanor that makes them so valuable. The author concludes that the best way to preserve professional reputation is to be independent, relevant, helpful, and respectful. © Wiley Periodicals, Inc., and the American Evaluation Association.
Developing policies to support valuing in the public interest
Authors: Julnes George
Published: March 2012

The author offers a framework for supporting valuing in the public interest, informed by a pragmatic approach that acknowledges and defends the value of multiple approaches to valuing. With our multiple approaches understood as tools for assisted sense making, the task for evaluators is to understand the factors that lead some tools to be more effective for valuing in particular contexts. Factors addressed include the decisions confronting stakeholders and the needed complexity and precision of valuation. The result is a more systematic and yet responsive framing that balances (a) individual and social valuation, (b) algorithmic and holistic approaches to summative conclusions, and (c) the often‐conflicting paradigms that structure other debates in evaluation. Tentative implications of this framework are suggested for the evaluation community, for government and foundation methodology policies, and for education and training. © Wiley Periodicals, Inc., and the American Evaluation Association.
Cognitive impairment in late life schizophrenia and bipolar I disorder
Authors: Meesters Paul D. , Schouws Sigfried , Stek Max , de Haan Lieuwe , Smit Jan , Eikelenboom Piet , Beekman Aartjan , Comijs Hannie
Published: March 2012

Objective

Evidence in younger populations suggests quantitative but not categorical differences in cognitive impairments between schizophrenia and bipolar disorder. It is uncertain whether a similar distinction applies to patients in later life.

Methods

We compared the cognitive abilities of older, community‐living schizophrenia patients, controlling for their state of symptomatic remission, with those of older euthymic patients with bipolar I disorder. The study included 67 patients with schizophrenia (20 in symptomatic remission, 47 not in symptomatic remission; mean age 68 years) and 74 euthymic bipolar I patients (mean age 70 years), who were compared using analysis of covariance on clinical and neuropsychological variables (e.g., attention/working memory, verbal memory, executive function and verbal fluency) and contrasted with 69 healthy controls.

Results

Remitted (SR) and non‐remitted (SN) schizophrenia patients and bipolar I (BP) patients were impaired relative to healthy controls, with mostly large effect sizes for verbal memory (Cohen's d: SR 1.34, SN 1.48, BP 1.09), executive function (Cohen's d: SR 0.87, SN 1.29, BP 0.71) and verbal fluency (Cohen's d: SR 1.09, SN 1.25, BP 0.88), but smaller effect sizes for the domain of attention/working memory (Cohen's d: SR 0.26, SN 0.18, BP 0.52). Differences in cognitive performance between the remitted schizophrenia patients and the bipolar I patients were not significant.

Conclusions

In both older patients with schizophrenia and with bipolar disorder, serious and pervasive cognitive deficits can be demonstrated. Trait‐related cognitive deficits in schizophrenia and bipolar disorder may share major phenotypic similarity in later life. Copyright © 2012 John Wiley & Sons, Ltd.
Incidence and risk factors for breast cancer subtypes in three distinct South‐East Asian ethnic groups: Chinese, Malay and natives of Sarawak, Malaysia
Authors: Devi C.R. Beena , Tang Tieng Swee , Corbex Marilys
Published: March 2012

We determined the incidences of the estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) subtypes among breast cancer cases in Sarawak, Malaysia and their correlation with various risk factors in the three ethnic groups: Chinese, Malay and native. Subtype status was ascertained for 1,034 cases of female breast cancer (93% of all cases diagnosed since 2003), and the age‐standardized incidence rates (ASRs) of each subtype were inferred. Case–case comparisons across subtypes were performed for reproductive risk factors. We found 48% luminal A (ER+/PR+/HER2−), 29% triple‐negative (ER−/PR−/HER2−), 12% triple‐positive (ER+/PR+/HER2+) and 11% HER2‐overexpressing (ER−/PR−/HER2+) subtypes, with ASRs of 10.6, 6.0, 2.8 and 2.8 per 100,000, respectively. The proportions of subtypes and ASRs differed significantly by ethnic groups: HER2‐positive cases were more frequent in Malays (29%; 95% CI [23;35]) than Chinese (22%; [19;26] and natives (21%; [16;26]); triple‐negative cases were less frequent among Chinese (23%; [20;27]) than Malays (33%; [27;39]) and natives (37%; [31;43]). The results of the case–case comparison were in accordance with those observed in western case series. Some uncommon associations, such as between triple‐negative subtype and older age at menopause (OR, 1.59; p < 0.05), were found. The triple‐negative and HER2+ subtypes predominate in our region, with significant differences among ethnic groups. Our results support the idea that the risk factors for different subtypes vary markedly. Westernized populations are more likely to have factors that increase the risk for the luminal A type, while risk factors for the triple‐negative type are more frequent in local populations.
Apoptotic responses of zebrafish (Danio rerio) after exposure with microcystin‐LR under different ambient temperatures
Authors: Ji Wei , Liang Hualei , Zhou Wenshan , Zhang Xuezhen
Published: March 2012

Microcystins (MCs) can cause evident hepatic apoptosis. In vitro studies indicated that uptake of MC by isolated hepatocytes was dramatically reduced as ambient temperature dropped, and some studies presented a hypothesis that differences in core body temperatures in animals result in diverse uptake of MC, as well as different toxic effects. Thus far, however, few in vivo studies have been conducted to investigate the effects of temperature on MC‐induced hepatocyte apoptosis in fish, a typical poikilotherm. In the present study, zebrafish were treated with MC‐LR, an MC metabolite, at three water temperatures (12, 22 and 32 °C), and evident differences in apoptotic profiles were observed. Damage to liver ultrastructures revealed temperature‐dependent early‐stage patterns of apoptosis. Flow‐cytometric analysis indicated that hepatocyte apoptotic rates varied with a temperature‐dependent effect. The transcription levels of some apoptosis‐related genes were determined using quantitative real‐time polymerase chain reaction, and significantly elevated gene expressions of P53, Bcl‐2, Bax and caspase‐3 were found in the 12 and 32 °C groups. Results of the present study indicate that different ambient temperatures can lead to various toxic effects of MCs on hepatic apoptosis in fish. Copyright © 2012 John Wiley & Sons, Ltd.
Misexpression of Dickkopf-1 in endothelial cells, but not in chondrocytes or hypertrophic chondrocytes, causes defects in endochondral ossification
Authors: Oh Hwanhee , Ryu Je-Hwang , Jeon Jimin , Yang Siyoung , Chun Churl-Hong , Park Hongryeol , Kim Hyung Joon , Kim Woo-Shin , Kim Hong-Hee , Kwon Young-Guen , Chun Jang-Soo
Published: March 2012

Developing cartilage serves as a template for long-bone development during endochondral ossification. Although the coupling of cartilage and bone development with angiogenesis is an important regulatory step for endochondral ossification, the molecular mechanisms are poorly understood. One possible mechanism involves the action of Dickkopf (DKK), which is a family of soluble canonical Wnt antagonists with four members (DKK1–4). We initially observed opposite expression patterns of Dkk1 and Dkk2 during angiogenesis and chondrocyte differentiation: downregulation of Dkk1 and upregulation of Dkk2. We examined the in vivo role of Dkk1 and Dkk2 in linking cartilage/bone development and angiogenesis by generating transgenic (TG) mice that specifically express Dkk1 or Dkk2 in chondrocytes, hypertrophic chondrocytes, or endothelial cells. Despite specific expression pattern during cartilage development, chondrocyte- and hypertrophic chondrocyte-specific Dkk1 and Dkk2 TG mice showed normal developmental phenotypes. However, Dkk1 misexpression in endothelial cells resulted in defects of endochondral ossification and reduced skeletal size. The defects are caused by the inhibition of angiogenesis in developing bone and subsequent inhibition of apoptosis of hypertrophic chondrocytes and cartilage resorption. © 2012 American Society for Bone and Mineral Research.
Temporal trends and determinants of longitudinal change in 25-hydroxyvitamin D and parathyroid hormone levels
Authors: Berger Claudie , Greene-Finestone Linda S , Langsetmo Lisa , Kreiger Nancy , Joseph Lawrence , Kovacs Christopher S , Richards J Brent , Hidiroglou Nick , Sarafin Kurtis , Davison K Shawn , Adachi Jonathan D , Brown Jacques , Hanley David A , Prior Jerilynn C , Goltzman David ,   the CaMos Research Group
Published: March 2012

Vitamin D is essential for facilitating calcium absorption and preventing increases in parathyroid hormone (PTH), which can augment bone resorption. Our objectives were to examine serum levels of 25-hydroxyvitamin D [25(OH)D] and PTH, and factors related to longitudinal change in a population-based cohort. This is the first longitudinal population-based study looking at PTH and 25(OH)D levels. We analyzed 3896 blood samples from 1896 women and 829 men in the Canadian Multicentre Osteoporosis Study over a 10-year period starting in 1995 to 1997. We fit hierarchical models with all available data and adjusted for season. Over 10 years, vitamin D supplement intake increased by 317 (95% confidence interval [CI] 277 to 359) IU/day in women and by 193 (135 to 252) IU/day in men. Serum 25(OH)D (without adjustment) increased by 9.3 (7.3 to 11.4) nmol/L in women and by 3.5 (0.6 to 6.4) nmol/L in men but increased by 4.7 (2.4 to 7.0) nmol/L in women and by 2.7 (−0.6 to 6.2) nmol/L in men after adjustment for vitamin D supplements. The percentage of participants with 25(OH)D levels <50 nmol/L was 29.7% (26.2 to 33.2) at baseline and 19.8% (18.0 to 21.6) at year 10 follow-up. PTH decreased over 10 years by 7.9 (5.4 to 11.3) pg/mL in women and by 4.6 (0.2 to 9.0) pg/mL in men. Higher 25(OH)D levels were associated with summer, younger age, lower body mass index (BMI), regular physical activity, sun exposure, and higher total calcium intake. Lower PTH levels were associated with younger age and higher 25(OH)D levels in both women and men and with lower BMI and participation in regular physical activity in women only. We have observed concurrent increasing 25(OH)D levels and decreasing PTH levels over 10 years. Secular increases in supplemental vitamin D intake influenced both changes in serum 25(OH)D and PTH levels. © 2012 American Society for Bone and Mineral Research.
The gut microbiota regulates bone mass in mice
Authors: Sjögren Klara , Engdahl Cecilia , Henning Petra , Lerner Ulf H , Tremaroli Valentina , Lagerquist Marie K , Bäckhed Fredrik , Ohlsson Claes
Published: March 2012

The gut microbiota modulates host metabolism and development of immune status. Here we show that the gut microbiota is also a major regulator of bone mass in mice. Germ-free (GF) mice exhibit increased bone mass associated with reduced number of osteoclasts per bone surface compared with conventionally raised (CONV-R) mice. Colonization of GF mice with a normal gut microbiota normalizes bone mass. Furthermore, GF mice have decreased frequency of CD4+ T cells and CD11b+/GR 1 osteoclast precursor cells in bone marrow, which could be normalized by colonization. GF mice exhibited reduced expression of inflammatory cytokines in bone and bone marrow compared with CONV-R mice. In summary, the gut microbiota regulates bone mass in mice, and we provide evidence for a mechanism involving altered immune status in bone and thereby affected osteoclast-mediated bone resorption. Further studies are required to evaluate the gut microbiota as a novel therapeutic target for osteoporosis. © 2012 American Society for Bone and Mineral Research.
Congenic mice provide in vivo evidence for a genetic locus that modulates intrinsic transforming growth factor β1–mediated signaling and bone acquisition
Authors: Mukherjee Aditi , Larson Emily A , Carlos Amy S , Belknap John K , Rotwein Peter , Klein Robert F
Published: March 2012

Osteoporosis, the most common skeletal disorder, is characterized by low bone mineral density (BMD) and an increased risk of fragility fractures. BMD is the best clinical predictor of future osteoporotic fracture risk, but is a complex trait controlled by multiple environmental and genetic determinants with individually modest effects. Quantitative trait locus (QTL) mapping is a powerful method for identifying chromosomal regions encompassing genes involved in shaping complex phenotypes, such as BMD. Here we have applied QTL analysis to male and female genetically-heterogeneous F2 mice derived from a cross between C57BL/6 and DBA/2 strains, and have identified 11 loci contributing to femoral BMD. Further analysis of a QTL on mouse chromosome 7 following the generation of reciprocal congenic strains has allowed us to determine that the high BMD trait, which tracks with the DBA/2 chromosome and exerts equivalent effects on male and female mice, is manifested by enhanced osteogenic differentiation of mesenchymal stem cells (MSCs) in vitro and by increased growth of metatarsal bones in short-term primary culture. An insertion/deletion DNA polymorphism in Ltbp4 exon 12 that causes the in-frame removal of 12 codons in the DBA/2-derived gene maps within 0.6 Mb of the marker most tightly linked to the QTL. LTBP4, one of four paralogous mouse proteins that modify the bioavailability of the transforming growth factor β (TGF-β) family of growth factors, is expressed in differentiating MSC-derived osteoblasts and in long bones, and reduced responsiveness to TGF-β1 is observed in MSCs of mice homozygous for the DBA/2 chromosome 7. Taken together, our results identify a potential genetic and biochemical relationship between decreased TGF-β1–mediated signaling and enhanced femoral BMD that may be regulated by a variant LTBP4 molecule. © 2012 American Society for Bone and Mineral Research.
Low-energy fractures of the humeral shaft and bisphosphonate use
Authors: Yavropoulou Maria P , Giusti Andrea , Ramautar Sharita R , Dijkstra Sander , Hamdy Neveen AT , Papapoulos Socrates E
Published: March 2012

Atypical fractures of the femur have been reported to occur in patients on long-term treatment with bisphosphonates; however, causality has not been proven, and it is not known whether similar fractures may occur in other long bones. We addressed this issue by examining the relationship between humeral shaft fractures and bisphosphonate use. We identified all patients aged ≥50 years consecutively admitted to a single center with a new fracture of the humerus. All individual radiographs were examined and fracture site was classified. A case-control study was undertaken in patients with humeral shaft fractures, and controls were sex- and age-matched patients with proximal humeral fractures in a 1:4 ratio. Patients with shaft fractures and radiographic characteristics similar to those of atypical femoral fractures were compared with those with ordinary shaft fractures. The association between “atypical” fractures and bisphosphonate or glucocorticoid use was examined. A total of 198 patients had a low-energy fracture of the humerus; 20 of these patients had a shaft fracture (10%). These 20 patients (cases) were matched with 80 patients with proximal fractures (controls). Bisphosphonates were used by 5% of cases and by 6.3% of controls (odds ratio [OR], 0.80; 95% confidence interval [CI], 0.09–6.85); glucocorticoids were used by 10% of cases and 8.8% of controls (OR, 1.15; 95% CI, 0.23–5.83). There was no difference in cortical thickness between cases and controls and bisphosphonate or glucocorticoid users and nonusers. Four of the 20 patients with shaft fractures had “atypical” radiographic features, with significantly increased cortical thickness, but none of these had ever been treated with bisphosphonates or glucocorticoids. Our results show that low-energy fractures of the humeral shaft with “atypical” radiographic characteristics are infrequent and are not associated with the use of bisphosphonates or glucocorticoids. © 2012 American Society for Bone and Mineral Research.
Pressure drop in biofilters as related to dust and biomass accumulation
Authors: Andreasen Rune R. , Nicolai Richard E. , Poulsen Tjalfe G.
Published: March 2012

BACKGROUND: Pressure drop is a key parameter controlling cost efficiency of air cleaning biofilters. Pressure drop tends to increase with time due to accumulation of dust and biomass (DBM) within the filter medium. Although this is well known no easily applied expression for accurately estimating pressure drop under such conditions is available. Thus, evaluation of filter operating costs is at present uncertain.

RESULTS: In this study the relationship between filter pressure drop and accumulation of DBM in the filter was examined using a commercial available material: light expanded clay aggregates (Leca®) consisting of porous rounded aggregates with similar shape. Pressure drop as a function of operating time (for a 60 day period), filter depth and DBM accumulation was measured on a set of pilot scale biofilter units filtering exhaust air from a full scale pig stable (as opposed to using artificially contaminated air). Pressure drop was observed to increase with time at all filter depths in response to DBM accumulation. Both DBM accumulation and pressure drop increase was most pronounced near the filter inlet.

CONCLUSION: Pressure drop and DBM accumulation were closely related and both linked to the fraction of air‐filled flow conducting voids. Based on the data a simple expression for predicting pressure drop in porous biofilter media as a function of DBM accumulation was developed. This expression can serve as an easily applied tool in assessment of biofilter cost efficiency. Copyright © 2012 Society of Chemical Industry
Sleep rounds: A multidisciplinary approach to optimize sleep quality and satisfaction in hospitalized patients
Authors: Thomas Katherine P. , Salas Rachel E. , Gamaldo Charlene , Chik Yolanda , Huffman Linda , Rasquinha Russell , Hoesch Robert E.
Published: March 2012

BACKGROUND:

Poor sleep has adverse affects on heath, yet few studies have addressed the goal of improving sleep among hospitalized patients. We evaluated the effectiveness of a sleep‐promoting intervention on the quality and quantity of sleep among inpatients.

METHODS:

This study was conducted on a neurological ward in a large, tertiary care hospital. Sleep quality, quantity, and disruptors were assessed using questionnaires completed by patients during their hospital stay and Press Ganey surveys completed retrospectively. Room noise was also measured using noise meters. Data from each of 4 chronological phases of the study (baseline, basic intervention, “washout,” and deluxe intervention) were analyzed. In the intervention phases, nurses conducted “Sleep Rounds” at bedtime, during which sleep‐promoting practices were implemented, including lights out, television off, temperature adjustment, and a final restroom usage.

RESULTS:

Patients reported 5 (interquartile range [IQR] 3) hours of sleep per night, awoke 3 (IQR 3) times nightly, and reported a median sleep latency of 11 to 15 minutes. Pain, staff interruptions, and roommates were the most significant barriers to good sleep. Noise levels were adequately low (35–40 dB) at night but were not positively impacted by our sleep‐promoting interventions. Patients perceived noise on the unit to be worse during phases of the study in which there was no intervention.

CONCLUSIONS:

Patient perception of sleep experience improved during the phases in which Sleep Rounds were implemented, despite the fact that there was no measurable improvement in sleep or sleep‐disrupting factors. Journal of Hospital Medicine 2012; © 2012 Society of Hospital Medicine
Detailing the use of magnetohydrodynamic effects for synchronization of MRI with the cardiac cycle: A feasibility study
Authors: Frauenrath Tobias , Fuchs Katharina , Dieringer Matthias A. , Özerdem Celal , Patel Nishant , Renz Wolfgang , Greiser Andreas , Elgeti Thomas , Niendorf Thoralf
Published: March 2012

Purpose:

To investigate the feasibility of using magnetohydrodynamic (MHD) effects for synchronization of magnetic resonance imaging (MRI) with the cardiac cycle.

Materials and Methods:

The MHD effect was scrutinized using a pulsatile flow phantom at B0 = 7.0 T. MHD effects were examined in vivo in healthy volunteers (n = 10) for B0 ranging from 0.05–7.0 T. Noncontrast‐enhanced MR angiography (MRA) of the carotids was performed using a gated steady‐state free‐precession (SSFP) imaging technique in conjunction with electrocardiogram (ECG) and MHD synchronization.

Results:

The MHD potential correlates with flow velocities derived from phase contrast MRI. MHD voltages depend on the orientation between B0 and the flow of a conductive fluid. An increase in the interelectrode spacing along the flow increases the MHD potential. In vivo measurement of the MHD effect provides peak voltages of 1.5 mV for surface areas close to the common carotid artery at B0 = 7.0 T. Synchronization of MRI with the cardiac cycle using MHD triggering is feasible. MHD triggered MRA of the carotids at 3.0 T showed an overall image quality and richness of anatomic detail, which is comparable to ECG‐triggered MRAs.

Conclusion:

This feasibility study demonstrates the use of MHD effects for synchronization of MR acquisitions with the cardiac cycle. J. Magn. Reson. Imaging 2012;36:364–372. © 2012 Wiley Periodicals, Inc.
Modelling variable glacier lapse rates using ERA‐Interim reanalysis climatology: an evaluation at Vestari‐ Hagafellsjökull, Langjökull, Iceland
Authors: Hodgkins R. , Carr S. , Pálsson F. , Guðmundsson S. , Björnsson H.
Published: March 2012

The near‐surface air temperature lapse rate is an important tool for spatially distributing temperatures in snow‐ and ice‐melt models, but is difficult to parameterize, as it is not simply correlated with boundary‐layer meteorological variables, such as temperature itself. This contribution quantifies spring‐autumn lapse rate variability over 5 years at Vestari‐Hagafellsjökull, a southerly outlet of Langjökull in Iceland. It is observed that summer lapse rates (0.57 °C 100 m−1) are significantly lower than non‐summer rates, and are also lower than the Saturated Adiabatic Lapse Rate (SALR), which is often adopted in melt models. This is consistent with reduced near‐surface temperature sensitivity to free‐atmosphere temperature change during the occurrence of melting. A Variable Lapse Rate (VLR) regression model is calibrated with standardized, 750 hPa temperature anomalies derived from ERA‐Interim climatology, which is shown to be highly significantly correlated with near‐surface temperatures. The modelled VLR overestimates cumulative June–September Positive Degree Days (PDDs) by 3% when used to extrapolate temperatures from 1100 to 500 m a.s.l. on the glacier, whereas the SALR overestimates cumulative PDDs by 14%. ERA‐Interim data therefore appear to offer a good representation of free‐atmosphere temperature variability over Vestari‐Hagafellsjökull, and the modelling approach offers a simple means of improving lapse rate parameterizations in melt models. Copyright © 2012 Royal Meteorological Society
Trends in extreme temperature indices in South Africa: 1962–2009
Authors: Kruger A. C. , Sekele S. S.
Published: March 2012

Trends in daily maximum and minimum extreme temperature indices were investigated for 28 weather stations in South Africa, not only for the common period of 1962–2009, but also for longer periods which the individual record lengths of the stations would allow. The utilized weather stations had limited gaps in their time series, did not undergo major moves, or had their exposure compromised during the study period, as to influence the homogeneity of their time series. The indices calculated were forthcoming from those developed by the WMO/CLIVAR Expert Team on Climate Change Detection and Indices (ETCCDI), but only those applicable to the South African climate were selected. The general result is that warm extremes increased and cold extremes decreased for all of the weather stations. The trends however vary on a regional basis, both in magnitude and statistical significance, broadly indicating that the western half, as well as parts of the northeast and east of South Africa, show relatively stronger increases in warm extremes and decreases in cold extremes than elsewhere in the country. These regions coincide to a large degree with the thermal regimes in South Africa which are susceptible to extreme temperatures. The annual absolute maximum and minimum temperatures do not reflect the general trends displayed by the other indices, showing that individual extreme events cannot always be associated with observed long‐term climatic trends. The analyses of longer time series than the common period indicate that it is highly likely that warming accelerated since the mid‐1960s in South Africa. Copyright © 2012 Royal Meteorological Society
Survival, fidelity, and recovery rates of white‐winged doves in Texas
Authors: Collier Bret A. , Kremer Shelly R. , Mason Corey D. , Peterson Markus J. , Calhoun Kirby W.
Published: March 2012

Management of migratory birds at the national level has historically relied on regulatory boundaries for definition of harvest restrictions and estimation of demographic parameters. Most species of migratory game birds are not expanding their ranges, so migratory corridors are approximately fixed. White‐winged doves (Zenaida asiatica), however, have undergone significant variation in population structure with marked range expansion occurring in Texas, and range contraction in Arizona, during the last 30 years. Because >85% of white‐winged dove harvest in the United States (approx. 1.3 million annually) now occurs in Texas, information on vital rates of expanding white‐winged dove populations is necessary for informed management. We used band recovery and mark–recapture data to investigate variation in survival and harvest across 3 geographic strata for white‐winged doves banded in the pre‐hunting season in Texas during 2007–2010. We banded 60,742 white‐winged doves, recovered 2,458 bands via harvest reporting, and recaptured 455 known‐age birds between 2007 and 2010. The best supporting model found some evidence for geographic differences in survival rates among strata (A–C) in both hatch‐year (juvenile; A = 0.205 [SE = 0.0476], B = 0.213 [SE = 0.0278], C = 0.364 [SE = 0.0254]) and after‐hatch year (adult; A = 0.483 [SE = 0.0775], B = 0.465 [SE = 0.0366], C = 0.538 [SE = 0.251]) birds. White‐winged doves had a low probability of moving among strata (0.009) or being recaptured (0.002) across all strata. Harvest recovery rates were concordant with estimates for other dove species, but were variable across geographic strata. Based on our results, harvest management strategies for white‐winged doves in Texas and elsewhere should consider differences in population vital rates among geographic strata. © 2012 The Wildlife Society.