bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diastereoselective and Enantioselective Michael Addition Reactions of Ketones and Aldehydes to Nitro Olefins Catalyzed by C2‐Symmetric Axially‐Unfixed Biaryl‐Based Organocatalysts Derived from Enantiopure α‐Proline
Authors: Zhao Hong‐Wu , Li Hai‐Long , Yue Yuan‐Yuan , Sheng Zhui‐Hui 
Published: February 2013

AbstractA new class of axially‐unfixed biaryl‐based pyrrolidines with C2‐symmetry were designed and synthesized by using enantiopure α‐proline as a chiral source. These bifunctional organocatalys provided Michael adducts in high chemical yields (up to 99 %) and with excellent stereoselectivities (up to 99:1 dr and 96 % ee) in the direct Michael addition reactions of a variety of ketones and aldehydes to nitro olefins. The transition states were proposed to clarify the stereochemical course of the examined reactions.
Historical changes in Australian temperature extremes as inferred from extreme value distribution analysis
Authors: Wang Xiaolan L. , Trewin Blair , Feng Yang , Jones David 
Published: February 2013

AbstractThis study develops a generalized extreme value (GEV) distribution analysis approach, namely, a GEV tree approach that allows for both stationary and nonstationary cases. This approach is applied to a century‐long homogenized daily temperature data set for Australia to assess changes in temperature extremes from 1910 to 2010. Changes in 20 year return values are estimated from the most suitable GEV distribution chosen from a GEV tree. Twenty year return values of extreme low minimum temperature are found to have warmed strongly over the century in most parts of the continent. There is also a tendency toward warming of extreme high maximum temperatures, but it is weaker than that for minimum temperatures, with the majority of stations not showing significant trends. The observed changes in extreme temperatures are broadly consistent with observed changes in mean temperatures and in the frequency of temperatures above the ninetieth and below the tenth percentile (i.e., extreme indices). The GEV tree analysis provides insight into behavior of extremes with re‐occurrence times of several years to decades that are of importance to engineering design/applications, while extreme indices represent moderately extreme events with re‐occurrence times of a year or shorter.
Bilateral kidney sodium‐MRI: Enabling accurate quantification of renal sodium concentration through a two‐element phased array system
Authors: Kalayciyan Raffi , Wetterling Friedrich , Neudecker Sabine , Haneder Stefan , Gretz Norbert , Schad Lothar R. 
Published: February 2013

Purpose:To develop a sodium‐MRI (23Na‐MRI) method for bilateral renal sodium concentration (RSC) measurements in rat kidneys at 9.4 Tesla (T).Materials and Methods:To simultaneously achieve high B1‐field homogeneity and high receive sensitivity a dual resonator system composed of a double‐tuned linearly polarized 1H/23Na volume resonator and a newly developed two‐element 23Na receive array was used. In conjunction with three‐dimensional (3D) ultra‐short Time‐to‐Echo sequence a quantification accuracy of ± 10% was achieved for a nominal spatial resolution of (1 × 1 × 4) mm3 in 10 min acquisition time. The technique was applied to study the RSC in six kidneys before and after furosemide‐induced diuresis.Results:The loop diuretic agent induced an increase of cortical RSC by 22% from 86 ± 16 mM to 105 ± 18 mM (P = 0.02), whereas the RSC in the inner medulla decreased by 38% from 213 ± 24 mM to 132 ± 25 mM (P = 0.8×10−4). The RSC changes measured in this study agreed well with the qualitative sodium signal intensity variations reported elsewhere.Conclusion:Furosemide‐induced diuresis has been investigated accurately with herein presented quantitative 23Na‐MRI technique. In the future, RSC quantification could allow for defining pathological and nonpathological RSC ranges to assess sodium concentration changes, e.g., induced by drugs. J. Magn. Reson. Imaging 2013;38:564–572. © 2013 Wiley Periodicals, Inc.
Accelerated T2*‐compensated fat fraction quantification using a joint parallel imaging and compressed sensing framework
Authors: Sharma Samir D. , Hu Houchun H. , Nayak Krishna S. 
Published: February 2013

PurposeTo develop a T2*‐compensated parallel imaging and compressed sensing framework for water‐fat separation, and to demonstrate accelerated quantitative imaging of proton density fat fraction.Materials and MethodsThe proposed method extends a previously developed framework for water‐fat separation by additionally compensating for T2* decay. A two‐stage estimation was formulated that first determines an approximation of the B0 field map and then jointly estimates and refines the R2* (=1/T2*) and B0 field maps, respectively. The method was tested using a set of water‐fat phantoms as well as liver datasets that were acquired from seven asymptomatic adult volunteers. The fat fraction estimates were compared to those from a commonly used nonaccelerated water‐fat imaging method and also to a sequential parallel imaging and water‐fat imaging method.ResultsThe proposed method properly compensated for T2* decay to yield accurate fat fraction estimates in the water‐fat phantoms. Further, linear regression analysis from the liver datasets showed that the proposed method accurately estimated fat fraction at acceleration factors that were higher than those achievable by the sequential parallel imaging and water‐fat imaging method. Accurate fat fraction estimates were demonstrated at acceleration factors up to 4×, although some image artifacts were observed.ConclusionThe proposed T2*‐compensated parallel imaging and compressed sensing framework demonstrates the potential to further accelerate water‐fat imaging while maintaining accurate estimates of proton density fat fraction. J. Magn. Reson. Imaging 2013;38:1267–1275. © 2013 Wiley Periodicals, Inc.
Characterization and limitations of diffusion tensor imaging metrics in the cervical spinal cord in neurologically intact subjects
Authors: Vedantam Aditya , Jirjis Michael B. , Schmit Brian D. , Wang Marjorie C. , Ulmer John L. , Kurpad Shekar N. 
Published: February 2013

PurposeTo characterize diffusion tensor imaging (DTI) metrics across all levels of the cervical spinal cord (CSC) and to study the impact of age and signal quality on these metrics.Materials and MethodsDTI metrics were calculated for gray matter (GM) and white matter (WM) funiculi throughout the CSC (C1–T1) in 25 healthy subjects (22‐85 years old). Signal‐to‐noise ratios (SNRs) and mean DTI metrics were measured for the upper (C1‐3), middle (C4‐6) and lower (C7‐T1) cervical segments. Age‐related changes in DTI metrics were analyzed for the individual segment groups.ResultsFractional anisotropy (FA), mean diffusivity (MD) and transverse apparent diffusion coefficient (tADC) showed significant differences between GM and WM funiculi. Significant age‐related changes were observed in FA in upper and middle CSC segments but not in the lower CSC. The median SNR was significantly lower in the middle and lower segment groups as compared to the upper levels, contributing to poor spatial resolution in these regions.ConclusionThis study provides DTI data for GM and WM funiculi throughout the CSC. While DTI metrics may be used to define cord pathology, variations in metrics due to age and signal quality need to be accounted for before making definitive conclusions. J. Magn. Reson. Imaging 2013;38:861–867. © 2013 Wiley Periodicals, Inc.
Supportive empirical modelling for the forecast of monsoon precipitation in Nepal
Authors: Gillies Robert R. , Wang Shih‐Yu , Sun Yan , Chung Oi‐Yu 
Published: February 2013

ABSTRACTSeasonal prediction of the monsoon precipitation in Nepal has been a challenge. That is partly because Nepal's monsoon precipitation exhibits a distinct and strong quasi‐decadal oscillation while not correlated with the El Nino‐Southern Oscillation. The existing global and regional climate models are insufficient in deriving reliable precipitation prediction. This paper examines the prediction of Nepal's July to August (JA) mean precipitation using five different methods: three time series models in comparison with a persistence forecast (PF) and a climatology forecast (CF). The first model (P‐AR) uses past precipitation data to forecast the future, based upon the recently uncovered quasi‐periodic feature of the JA mean precipitation. The other two models (ARX‐SST and ARX‐GQ) add covariate sea surface temperature (SST) and global water vapour flux circulation (GQ) respectively. Based upon the evaluation of 1‐year‐ahead forecast, the three time series models performed better than PF and CF. Of those, the P‐AR model has the least mean absolute error (MAE) of <1 mm day–1. Based upon the 2‐year‐ahead forecast results, the P‐AR model performs slightly better than ARX‐SST and ARX‐GQ models. The forecast ability of the time series models appears better than that of operational numerical models such as the NCEP Climate Forecast System (CFS) and so, can be used as an effective alternative in predicting monsoon precipitation for Nepal.
Mitochondrial‐derived reactive oxygen species (ROS) play a causal role in aging‐related intervertebral disc degeneration
Authors: Nasto Luigi A. , Robinson Andria R. , Ngo Kevin , Clauson Cheryl L. , Dong Qing , St. Croix Claudette , Sowa Gwendolyn , Pola Enrico , Robbins Paul D. , Kang James , Niedernhofer Laura J. , Wipf Peter , Vo Nam V. 
Published: February 2013

AbstractOxidative damage is a well‐established driver of aging. Evidence of oxidative stress exists in aged and degenerated discs, but it is unclear how it affects disc metabolism. In this study, we first determined whether oxidative stress negatively impacts disc matrix metabolism using disc organotypic and cell cultures. Mouse disc organotypic culture grown at atmospheric oxygen (20% O2) exhibited perturbed disc matrix homeostasis, including reduced proteoglycan synthesis and enhanced expression of matrix metalloproteinases, compared to discs grown at low oxygen levels (5% O2). Human disc cells grown at 20% O2 showed increased levels of mitochondrial‐derived superoxide anions and perturbed matrix homeostasis. Treatment of disc cells with the mitochondria‐targeted reactive oxygen species (ROS) scavenger XJB‐5‐131 blunted the adverse effects caused by 20% O2. Importantly, we demonstrated that treatment of accelerated aging Ercc1−/Δ mice, previously established to be a useful in vivo model to study age‐related intervertebral disc degeneration (IDD), also resulted in improved disc total glycosaminoglycan content and proteoglycan synthesis. This demonstrates that mitochondrial‐derived ROS contributes to age‐associated IDD in Ercc1−/Δ mice. Collectively, these data provide strong experimental evidence that mitochondrial‐derived ROS play a causal role in driving changes linked to aging‐related IDD and a potentially important role for radical scavengers in preventing IDD. © 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:1150–1157, 2013
What, Methane Again?!
Authors: Golden David M. 
Published: February 2013

ABSTRACTA combination of an error discovered in the Multiwell code and some more recent examinations of the system CH3 + H = CH4 prompted a reexamination of earlier work by this author. Values of the energy transfer parameter, 〈ΔEd〉, are considerably different from the previous study. It is suggested that the Baulch et al. parameters for this system can be improved by replacing the values for krec,0 and krec,∞ with values suggested by Troe and Ushakov. krec,0 = [Ar] 10−26.19 exp[–(T/21.22 K)0.5] cm6 molecule−2 s−1, krec,∞ = 3.34 × 10−10 (T/25200 K)0.186 cm3 molecule−1 s−1 while keeping their value for Fc = 0.63 exp(–T/3315) + 0.37 exp(–T/61).
A consistency proof for some restrictions of Tait's reflection principles
Authors: McCallum Rupert 
Published: February 2013

AbstractIn5, Tait identifies a set of reflection principles called\documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\Gamma ^{(2)}_{n}$\end{document}‐reflection principles which Peter Koellner has shown to be consistent relative to the existence of κ(ω), the first ω‐Erdős cardinal1. Tait also defines a set of reflection principles called\documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\Gamma ^{(m)}_{n}$\end{document}‐reflection principles; however, Koellner has shown that these are inconsistent whenm> 2, but identifies restricted versions of them which he proves consistent relative to κ(ω)2. In this paper, we introduce a new large‐cardinal property, the α‐reflective cardinals. Their definition is motivated by Tait's remarks on parameters of third or higher order in reflection principles. We prove that if κ is ℶκ + α + 1‐supercompact and 0 < α < κ then κ is α‐reflective. Furthermore we show that α‐reflective cardinals relativize to L, and that if κ(ω) exists then the set of cardinals λ < κ(ω), such that λ is α‐reflective for all α such that 0 < α < λ, is a stationary subset of κ(ω). We show that an ω‐reflective cardinal satisfies some restricted versions of\documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\Gamma ^{(m)}_{n}$\end{document}‐reflection, as well as all the reflection properties proved consistent in2.
Star‐Shaped Polymer Consisting of a Porphyrin Core and Poly(L‐lysine) Dendron Arms: Synthesis, Drug Delivery, and In Vitro Chemo/Photodynamic Therapy
Authors: Ma Dong , Liu Zong‐Hua , Zheng Qian‐Qian , Zhou Xiao‐Yan , Zhang Yi , Shi Yun‐Feng , Lin Jian‐Tao , Xue Wei 
Published: February 2013

AbstractA novel star‐shaped polymer, porphyrin‐poly(L‐lysine) dendrons (PP‐PLLD), is synthesized by the click reaction between azido‐modified porphyrin and propargyl focal point poly(L‐lysine) dendrons. Its chemical structure is characterized by 1H nuclear magnetic resonance, Fourier transform infrared spectroscopy, and gel permeation chromatography (GPC) is analyses etc. Due to its amphiphilic property, the obtained PP‐PLLD has a low critical micelle concentration in an aqueous solution, and can load doxorubicin (DOX) with a loading amount of 64 μg mg−1. By in vitro toxicity assay, PP‐PLLD has no dark cytotoxicity but has significant phototoxicity. Moreover, DOX‐loaded PP‐PLLD shows a higher cytotoxicity under the light condition than PP‐PLLD or DOX alone, suggesting PP‐PLLD has a potential application in combined photodynamic therapy and chemotherapy.
Polydiacetylene Liposome Microarray Toward Influenza A Virus Detection: Effect of Target Size on Turn‐On Signaling
Authors: Seo Sungbaek , Lee Jiseok , Choi Eun‐Jin , Kim Eun‐Ju , Song Jae‐Young , Kim Jinsang 
Published: February 2013

AbstractTarget size effect on the sensory signaling intensity of polydiacetylene (PDA) liposome microarrays was systematically investigated. Influenza A virus M1 peptide and M1 antibody were selected as a probe–target pair. While red fluorescence from the PDA liposome microarrays was observed when the larger M1 antibody was used as a target, when the same M1 antibody was used as a probe to detect the smaller M1 peptide sensory signal did not appear. The results reveal that the intensity of the PDA sensory signal is mainly related to the steric repulsion between probe–target complexes not the strength of the probe–target binding force. Based on this finding, we devised a PDA sensory system that directly detects influenza A whole virus as a larger target, and confirmed the target size effect on the signaling efficiency of PDA.magnified image
The molecular chaperone cosmc enhances malignant behaviors of colon cancer cells via activation of Akt and ERK
Authors: Huang John , Che Mei‐Ieng , Lin Neng‐Yu , Hung Ji‐Shiang , Huang Yu‐Ting , Lin Wei‐Chou , Huang Hsiu‐Chin , Lee Po‐Huang , Liang Jin‐Tung , Huang Min‐Chuan 
Published: February 2013

AbstractExpression of T antigen (Galbeta1, 3GalNAc) is associated with enhanced metastatic potential and poor prognosis in colorectal cancer. Cosmc is a molecular chaperone required for the formation of an active T‐synthase, which catalyzes the synthesis of T antigen. However, the expression and role of Cosmc in colorectal cancer are still unclear. Here, real‐time PCR showed that overexpression of Cosmc mRNA in colorectal tumors compared with paired non‐tumorous tissues was associated with increased American Joint Committee on Cancer (AJCC) tumor stage. Forced expression of Cosmc in HCT116 cells significantly increased T antigen expression and enhanced cell growth, migration, and invasion, which was associated with increased phosphorylation of focal adhesion kinase (FAK), ERK, and Akt. These Cosmc‐enhanced malignant phenotypes were significantly suppressed by specific inhibitor of MEK or PI3K. We also found that Cosmc overexpression increased tumor growth and decreased survival of tumor‐bearing SCID mice. Conversely, knockdown of Cosmc with siRNA in SW480 cells decreased malignant behaviors and the signaling pathways, which were substantially reversed by constitutively active Akt or MEK. Taken together, these results suggest that Cosmc promotes malignant phenotypes of colon cancer cells mainly via activation of MEK/ERK and PI3K/Akt signaling pathways, and that Cosmc may serve as a potential target for colorectal cancer treatment. © 2013 Wiley Periodicals, Inc.
Hip fractures in people with idiopathic Parkinson's disease: Incidence and outcomes
Authors: Walker Richard W. , Chaplin Andrew , Hancock Rebecca L. , Rutherford Rachel , Gray William K. 
Published: February 2013

ABSTRACTThe incidence of hip fracture and outcomes from hip surgery for people with Parkinson's disease (PD) are thought to be poorer than for people without PD. The aim of this audit of a prospective hip‐fracture database was to establish the incidence of, and outcomes from, hip fracture in people with and without PD living in North East England. The number of people with PD living in the study area was estimated using data from two previous prevalence studies in the same geographical area. Using data collected prospectively for the National Hip Fracture Database for Northumbria Healthcare National Health Service Foundation Trust in the UK, the annual incidence of hip fracture in people with and without PD was calculated. Type of fracture, time to surgery, time to discharge, and 30‐day outcomes from surgery were compared. Annual incidence of hip fracture was significantly higher in people with PD across all age bands. In those 60 years of age and over, it was 2,171 (95% confidence interval [CI]: 2,082–2,264) per 100,000 in people with PD and 551 (95% CI: 506–598) in people without PD. The experience of PD and non‐PD patients within hospital was remarkably similar. However, PD patients had poorer mobility before hip fracture, took longer to be discharged to the community, and were less mobile postsurgery. Specific guidelines for managing people with PD who sustain a hip fracture may help to improve awareness of the potential complications of the condition and improve outcomes. © 2012 Movement Disorder Society
Longitudinal study of levodopa in Parkinson's disease: Effects of the advanced disease phase
Authors: Ganga Ganesvaran , Alty Jane E. , Clissold Benjamin G. , McColl Craig D. , Reardon Katrina A. , Schiff Mark , Kempster Peter A. 
Published: February 2013

ABSTRACTThirty‐four patients have been studied from the time of initiation of pharmacological treatment in a long‐term prospective study of levodopa effects and disease progression in Parkinson's disease. Objective motor scoring of the response to levodopa in defined off states was performed every 3 years. The mean time from the initiation of levodopa treatment to the most recent measurements was 18.2 years. Of 8 patients who are still alive, only 3 had none of the features of the advanced disease phase (dementia, hallucinations, frequent falling). Off‐phase motor function worsened at a yearly rate of 1.9% of the maximum disability score, although the plots of the serial scores showed that the magnitude of the levodopa response is well preserved. There was little difference in the rate of progression between patients with tremor‐dominant and non‐tremor‐dominant motor subtypes. Those who developed dementia had more rapid deterioration of motor scores, with significantly worse off‐phase (P = .008) and on‐phase (P = .03) motor function. A graph of serial scores of patients who have died, aligned for time of death, showed an upward curving trend of motor disability in the last 5 years of the disease course. Its advanced phase may reveal that Parkinson's disease has an exponential pattern of progression. © 2013 Movement Disorder Society
X‐linked Dystonia‐Parkinsonism manifesting in a female patient due to atypical turner syndrome
Authors: Westenberger Ana , Rosales Raymond L. , Heinitz Sascha , Freimann Karen , Lee Lilian V. , Jamora Roland D. , Ng Arlene R. , Domingo Aloysius , Lohmann Katja , Walter Uwe , Gölnitz Uta , Rolfs Arndt , Nagel Inga , Gillessen‐Kaesbach Gabriele , Siebert Reiner , Dressler Dirk , Klein Christine 
Published: February 2013

ABSTRACTBackgroundRecessive X‐linked dystonia‐parkinsonism almost exclusively affects men. We investigated the genetic mechanisms causing this disorder in a female patient.MethodsWe confirmed the presence of an X‐linked dystonia‐parkinsonism–specific change in our patient by sequencing. In addition, we employed quantitative real‐time PCR and array comparative genomic hybridization to determine the patient's X‐chromosome copy number.ResultsThe patient's sequence electropherogram suggested a higher amount of the mutated allele compared with the wild‐type allele. Subsequently, extensive gene dosage analyses revealed a copy number of the X chromosomes between 1 and 2, indicating loss of 1 X chromosome in a subset of cells. Phenotypic reevaluation of the patient showed several clinical features of Turner syndrome.ConclusionsOur female X‐linked dystonia‐parkinsonism patient suffered from an undiagnosed X‐chromosome monosomy in a subset of cells (45,X/46,XX), suggesting an atypical Turner syndrome and contributing the first molecular explanation for the manifestation of an X‐linked dystonia‐parkinsonism phenotype in women. © 2013 Movement Disorder Society
Oxidation of high doses of serotonin favors lipid accumulation in mouse and human fat cells
Authors: Grès Sandra , Canteiro Sarah , Mercader Josep , Carpéné Christian 
Published: February 2013

ScopeThe ingestion of serotonin‐rich food (bananas, chocolate) increases 5‐hydroxytryptamine (5‐HT) in blood and its corresponding oxidation products in urines but without direct central consequences since the neurotransmitter does not easily cross the blood‐brain barrier. However, there are numerous peripheral effects of serotonin, and recently, 5‐HT aldehydic oxidation products have been demonstrated to behave as ligands of peroxisome proliferator‐activated receptor γ (PPAR‐γ). Since this nuclear factor manages lipid handling by adipose tissue, the response of fat cells to 5‐HT exposure needed further investigation.Methods and resultsSerotonin oxidation was studied on human adipose tissue homogenates and mouse 3T3F442A preadipocytes by fluorometric and radiometric methods. Gene expression was assessed by real‐time RT‐PCR in human adipocytes and in 3T3F442A after mid‐ and long‐term exposure to 5‐HT while triacylglycerols and proteins were assessed by spectrophotometry. Six‐hour exposure of human adipocytes to 250 μM 5‐HT increased gene expression of lipid‐binding proteins, glucose carriers, and enzymes of triacylglycerol synthesis (FABP4, CD36, GLUT1, and phosphoenolpyruvate carboxykinase), as did rosiglitazone treatment. Long‐term serotoninergic stimulation of cultured 3T3F442A preadipocytes by 100–250 μM 5‐HT enhanced fat storage and upregulation of PPAR‐γ‐responsive genes, in a manner sensitive to MAO‐ or PPAR‐γ inhibition. Our observations suggest an unpredicted peripheral effect of serotonin on adipose tissue that depends on its amine oxidation.ConclusionBesides being centrally active on eating behavior, 5‐HT may promote PPAR‐γ activation and subsequent lipogenic effects in fat cells, raising the interest to consider its level in future diet formulations.