bluuebunny/crossref_metadata_2025_split huggingface dataset:
Purification of Enantiomeric Mixtures in Enantioselective Synthesis: Overlooked Errors and Scientific Basis of Separation in Achiral Environment
Authors: Martens Jürgen , Bhushan Ravi 
Published: February 2014

AbstractThe syntheses of optically active compounds (whether of pharmaceutical or synthetic importance, or as promising candidates as chiral ligands and auxiliaries in asymmetric syntheses) result in the formation of a mixture of products with one enantiomer predominating. Usually, the practice is to use standard open‐column chromatography for the first purification step in an enantioselective synthesis; the workup of the reaction product by crystallization or achiral chromatography would mask the real efficiency of the enantioselective methodology, since enantiomeric ratio (er) of the product may change by any of these methods. Most of the synthetic organic chemists are aware of the influence of crystallization on the er value.Majority of synthetic organic chemists are, however, not aware, while employing standard chromatography, that there may be an increase or decrease of er value. In other words, an undesired change in er goes unnoticed when such a mixture of enantiomers is isolated by chromatography on an achiral‐phase because of the prevalent concept of basic stereochemistry. Such unnoticed errors in enantioselective reactions may lead to misinterpretations of the enantioselective outcome of the synthesis. The scientific issue is, what is the difference between a racemic and nonracemic mixture in achiral environment (e.g., achiral‐phase chromatography) that leads to enantiomeric enrichment, amounting to separation of one particular enantiomer?There are sporadic reports on enantiomer separation of nonracemic mixtures in an achiral environment particularly from the scientists working in analytical chemistry. To cover/discuss all these reports is out of the scope of this article.The aim of the present report is to draw attention to the following points: i) How should the synthetic organic chemists and analytical chemists take care of the unexpected separation of enantiomers from nonracemic mixtures in a totally achiral environment? ii) What are the technical terms used in recent literature? iii) The requirement of revisiting definitions/terms (introduced in recent years, in particular) to describe such separations of enantiomers in light of prevalent scientific/chemical terminology used in the ‘language of chemistry’, the text book concept, and IUPAC background. iv) To propose logical scientific terminology or phrases for explaining the possible mechanism of separation under these conditions. v) To discuss briefly the concept/possibile phenomenon responsible for these enantioselective effects. It is also attempted to explain the effect of change of physical parameters influencing the separation from nonracemic mixture in achiral‐phase chromatography.
New bone formation enhanced by ADSCs overexpressing hRunx2 during mandibular distraction osteogenesis in osteoporotic rabbits
Authors: Sun Jing‐Jing , Zheng Xiao‐Hui , Wang Li‐Ya , Liu Lei , Jing Wei , Lin Yun‐Feng , Tian Weidong , Tang Wei , Long Jie 
Published: February 2014

ABSTRACTPromoting new bone formation during distraction osteogenesis (DO) in elderly patients with osteoporosis is still a challenge. In this study, we investigated the effect of gene therapy using local Runt‐related gene 2 on new bone formation during osteoporotic mandibular DO in rabbits. First, we successfully established a mandibular osteoporotic animal model by ovariectomizing rabbits. Second, the right mandibles of the osteoporotic rabbits were distracted after corticotomy. The distraction gap of the rabbits in Group A2 and B2 were injected with Adv‐hRunx2‐GFP‐transfected adipose‐derived stromal cells (ADSCs) and Adv‐GFP‐transfected ADSCs, respectively. Rabbits in Groups C2 (ovariectomized control) and D2 (sham surgery control) were injected with physiologic saline. New‐generation bone tissue in the distraction gap was analyzed via plain radiographic examinations, micro‐computed tomography, histological examinations, and biomechanical testing at weeks 3, 6, and 9 of the consolidation period. Results of above examinations showed that no ideal new bone formation was observed in Groups B2 and C2, but obvious ideal new bone formation was observed in Group A2 and D2. The results suggested that gene therapy using rhRunx2‐modified ADSCs promoted new bone formation during osteoporotic mandibular DO and effectively compensated for the detrimental effects of systemic osteoporosis on new bone formation. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:709–720, 2014.
Three‐dimensional motion analysis of the patellar component in total knee arthroplasty by the image matching method using image correlations
Authors: Ishimaru Masami , Shiraishi Yoshitaka , Ikebe Satoru , Higaki Hidehiko , Hino Kazunori , Onishi Yoshio , Miura Hiromasa 
Published: February 2014

ABSTRACTIn total knee arthroplasty (TKA), the patella is significantly associated with range of motion and gait performance. Currently, no highly accurate methods are available that can measure the 3D in vivo behavior of the TKA patellar component, as the component is made of x‐ray‐permeable ultra‐high molecular weight polyethylene. Previously, we developed a computer simulation that matches CT scan and unidirectional radiographic images using image correlations, and applied it to kinematic studies of natural and TKA knees. The examination of the measurement accuracy for the patellar bone of a fresh‐frozen pig knee joint yielded a root mean square error of 0.2 mm in translation and 0.2° in rotation. In this study, we recruited four patients who had a TKA and investigated 3D movements of the patellar component during squatting. We could visualize the patellar component using the position of the holes drilled for the component peg, and estimated and visualized the contact points between the patellar and femoral components. The principles and the utility of the simulation method are reported. This analytical method is useful for evaluating the pathologies and post‐surgical conditions of the knee and other joints. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:619–626, 2014.
The First Photochemical In Situ Production of Ti‐Based Nanoparticles: A SH2 Strategy Using Bis(cyclopentadienyl)titanium Dichloride (Cp2TiCl2)
Authors: Versace Davy‐Louis , Fouassier Jean‐Pierre , Lalevée Jacques 
Published: February 2014

Bis(cyclopentadienyl)titanium dichloride (Cp2TiCl2) is a high performance additive under UV light activation for both i) radical photopolymerization reactions (when added to a Type I photo­initiator such as 2,2‐dimethoxy‐2‐phenylacetophenone, the oxygen inhibition is reduced) and ii) a concomitant in situ photoinduced and oxygen mediated formation of Ti‐based nanoparticles (diameters ranging from 45 to 220 nm). The photochemical properties of Cp2TiCl2 are investigated by steady state photolysis and electron spin resonance, and its photoinitiation ability checked. The nanoparticles (NPs) are well characterized by transmission electron microscopy. The high reactivity of Cp2TiCl2 under air is ascribed to a bimolecular homolytic substitution (the SH2 process is clearly demonstrated by density functional theory calculations and ESR experiments), which converts the peroxyls into new efficient initiating radicals. The photochemical in situ incorporation of Ti NPs has never previously been reported. The synthesis of metal nanoparticles by a SH2 approach instead of the reduction of a metal salt appears to be a promising original method.
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Weak Galerkin finite element methods for the biharmonic equation on polytopal meshes
Authors: Mu Lin , Wang Junping , Ye Xiu 
Published: February 2014

AbstractA new weak Galerkin (WG) finite element method is introduced and analyzed in this article for the biharmonic equation in its primary form. This method is highly robust and flexible in the element construction by using discontinuous piecewise polynomials on general finite element partitions consisting of polygons or polyhedra of arbitrary shape. The resulting WG finite element formulation is symmetric, positive definite, and parameter‐free. Optimal order error estimates in a discrete H2 norm is established for the corresponding WG finite element solutions. Error estimates in the usual L2 norm are also derived, yielding a suboptimal order of convergence for the lowest order element and an optimal order of convergence for all high order of elements. Numerical results are presented to confirm the theory of convergence under suitable regularity assumptions. © 2014 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 30: 1003–1029, 2014
Patterns of failure after involved field radiation therapy for pediatric and young adult Hodgkin lymphoma
Authors: Huynh‐Le Minh‐Phuong , Walker Amanda J. , Kominers Scott Duke , Paz‐Priel Ido , Wharam Moody D. , Terezakis Stephanie A. 
Published: February 2014

BackgroundInvolved field radiation therapy (IFRT) is integral in curative therapy for Hodgkin lymphoma (HL), although primarily used in patients with intermediate/high‐risk HL. We present failure patterns and clinical outcomes in a cohort of pediatric and young adult patients with HL treated with IFRT at the Johns Hopkins Hospital.ProcedurePatients ≤40 years old with intermediate/high‐risk HL who received chemotherapy and IFRT from 1997 to 2012 were included in this retrospective analysis. Patients were evaluated for failure patterns, overall survival (OS), and event‐free survival (EFS) using Kaplan–Meier curves, descriptive statistics, and Cox proportional hazard regressions.ResultsWe reviewed 74 patients (45 pediatric and 29 young adult) with a median follow‐up of 4.4 years. The mean age at diagnosis was 21.4 years. Patients received a median of 29.75 Gy of IFRT (range 15–39.6 Gy). The majority of pediatric patients received ABVE‐PC chemotherapy (n = 25) and <30 Gy of radiation (n = 33) while most young adults received ABVD chemotherapy (n = 24) and ≥30 Gy (n = 25). Estimated 5‐year OS and EFS were 96% and 81%, respectively. Thirteen patients had recurrence; eight were pediatric. Distant relapse alone comprised 83% of failures in patients receiving ≥30 Gy. Of the seven patients who received <30 Gy and had recurrence, six had local failure as a component of their recurrence. Caucasian race (P = 0.02) and nodular sclerosing histology (P = 0.01) predicted for increased EFS. Late effects were minimal and all deaths (n = 4) were from HL.ConclusionsIn this series, pediatric and young adult patients were treated with differing chemoradiation and had distinct recurrence patterns. Pediatr Blood Cancer 2014;61:1210–1214. © 2014 Wiley Periodicals, Inc.
Synthetic adhesive attachment discs inspired by spider's pyriform silk architecture
Authors: Jain Dharamdeep , Sahni Vasav , Dhinojwala Ali 
Published: February 2014

ABSTRACTSpiders attach their major ampullate silk dragline fibers to surfaces using attachment discs spun from pyriform silk fibers. These attachment discs allow spiders to move safely from place to place while secured to a dragline and to attach their webs to a variety of surfaces. Here, we demonstrate a simple electrospinning process to mimic the “staple‐pin” architecture used by spiders for these attachment discs. Experimental and theoretical evidence are provided to confirm the advantages of thousands of micron‐size “staple‐pins” and their low peeling angles to enhance the adhesive forces required to peel the natural and synthetic attachment discs. These results provide a unique architectural design for fabricating new adhesives that uses very little material for various biomedical and material science applications. © 2014 Wiley Periodicals, Inc. J Polym Sci Part B: Polym. Phys. 2014, 52, 553–560
Laser desorption time‐of‐flight mass spectrometry of atomic switch memory Ge2Sb2Te5 bulk materials and its thin films
Authors: Houška Jan , Peña‐Méndez Eladia Maria , Kolář Jakub , Přikryl Jan , Pavlišta Martin , Frumar Miloslav , Wágner Tomáš , Havel Josef 
Published: February 2014

RATIONALEAlthough the structure of atomic switch Ge2Sb2Te5 (GST) thin films is well established, the composition of the clusters formed in the plasma plume during pulsed‐laser deposition (PLD) is not known. Laser Desorption Ionization Time‐of‐Flight Mass Spectrometry (LDI‐TOF MS) is an effective method for the generation and study of clusters formed by laser ablation of various solids and thus for determining their structural fragments.METHODSLDI of bulk or PLD‐deposited GST thin layers and of various precursors (Ge, Sb, Te, and Ge‐Te or Sb‐Te mixtures) using a nitrogen laser (337 nm) was applied while the mass spectra were recorded in positive and negative ion modes using a TOF mass spectrometer equipped with a reflectron while the stoichiometry of the clusters formed was determined via isotopic envelope analysis.RESULTSThe singly negatively or positively charged clusters identified from the LDI of GST were Ge, Ge2, GeTe, Ge2Te, Ten (n = 1–3), GeTe2, Ge2Te2, GeTe3, SbTe2, Sb2Te, GeSbTe2, Sb3Te and the low abundance ternary GeSbTe3, while the LDI of germanium telluride yielded GemTen+ clusters (m = 1–3, n = 1–3). Several minor Ge‐H clusters were also observed for pure germanium and for germanium telluride. Sbn clusters (n = 1–3) and the formation of binary TeSb, TeSb2 and TeSb3 clusters were detected when Sb2Te3 was examined.CONCLUSIONSThis is the first report that elucidates the stoichiometry of GemSbnTep clusters formed in plasma when bulk or nano‐layers of GST material are ablated. The clusters were found to be fragments of the original structure. The results might facilitate the development of PLD technology for this memory phase‐change material. Copyright © 2014 John Wiley & Sons, Ltd.
A rapid and high‐precision method for sulfur isotope δ34S determination with a multiple‐collector inductively coupled plasma mass spectrometer: matrix effect correction and applications for water samples without chemical purification
Authors: Lin An‐Jun , Yang Tao , Jiang Shao‐Yong 
Published: February 2014

RATIONALEPrevious studies have indicated that prior chemical purification of samples, although complex and time‐consuming, is essential in obtaining precise and accurate results for sulfur isotope ratios using multiple‐collector inductively coupled plasma mass spectrometry (MC‐ICP‐MS). In this study, we introduce a new, rapid and precise MC‐ICP‐MS method for sulfur isotope determination from water samples without chemical purification.METHODSThe analytical work was performed on an MC‐ICP‐MS instrument with medium mass resolution (m/Δm ~ 3000). Standard‐sample bracketing (SSB) was used to correct samples throughout the analytical sessions. Reference materials included an Alfa‐S (ammonium sulfate) standard solution, ammonium sulfate provided by the lab of the authors and fresh seawater from the South China Sea. A range of matrix‐matched Alfa‐S standard solutions and ammonium sulfate solutions was used to investigate the matrix (salinity) effect (matrix was added in the form of NaCl). A seawater sample was used to confirm the reliability of the method.RESULTSUsing matrix‐matched (salinity‐matched) Alfa‐S as the working standard, the measured δ34S value of AS (−6.73 ± 0.09‰) was consistent with the reference value (−6.78 ± 0.07‰) within the uncertainty, suggesting that this method could be recommended for the measurement of water samples without prior chemical purification. The δ34S value determination for the unpurified seawater also yielded excellent results (21.03 ± 0.18‰) that are consistent with the reference value (20.99‰), thus confirming the feasibility of the technique.CONCLUSIONSThe data and the results indicate that it is feasible to use MC‐ICP‐MS and matrix‐matched working standards to measure the sulfur isotopic compositions of water samples directly without chemical purification. In comparison with the existing MC‐ICP‐MS techniques, the new method is better for directly measuring δ34S values in water samples with complex matrices; therefore, it can significantly accelerate analytical turnover. Copyright © 2014 John Wiley & Sons, Ltd.
Influence of Texture on Welding Stress Calculations
Authors: Decroos Koen , Ohms Carsten , Petrov Roumen , Seefeldt Marc , Verhaeghe Frederik , Kestens Leo 
Published: February 2014

AbstractUpon solidification of the fusion zone of an austenitic weld the grains have a preferential <100> orientation aligning with the macroscopic solidification direction. The bulk material properties are consequently locally transversally isotropic with the solidification direction as fiber axis. A method is described to calculate the elastic and plastic anisotropy of the fusion zone bulk material and to implement the transversal isotropic material in Finite Element models for welding stress calculations. Results show a difference in predicted stress in the vicinity of the fusion zone when compared with a model with isotropic material properties.
Microwave‐Assisted Nonaqueous Synthesis of Doped Ceria Nanoparticles Assembled into Flakes
Authors: Hilaire Sandra , Luo Li , Rechberger Felix , Krumeich Frank , Niederberger Markus 
Published: February 2014

AbstractUndoped and doped CeO2nanoparticles were synthesized through a combination of microwave‐assisted nonaqueous sol‐gel route and thermal treatment at 300 °C. Nanocrystals of 3 nm were obtained and characterized in detail by Rietveld refinement analysis of the X‐ray diffraction data and by electron microscopy. The refinement indicated that the doping with 3d transition metals (Co, Cu, Fe, and Ni) was successfully achieved and this result was additionally confirmed by EDX measurements. Investigation of the particle morphology by electron microscopy revealed that the nanocrystals were generally not present as primary particles, but self‐assembled into often intergrown flakes with uniform diameters of about 150 nm. In selected cases, the ceria nanocrystals are crystallographically oriented with respect to each other within one flake. BET measurements revealed a high surface area of 126 m2·g–1.
Comparison of Fatty Acid Profile of Specialty Maize to Normal Maize
Authors: Sanjeev P. , Chaudhary D. P. , Sreevastava P. , Saha S. , Rajenderan A. , Sekhar J. C. , Chikkappa G. K. 
Published: February 2014

AbstractIncreasing utilization of specialty maize prompted us to evaluate its fatty acid profile. For this purpose maize germplasm, classified as low oil normal maize (group 1), high oil normal maize (group 2), quality protein maize (QPM) (group 3) and sweet corn (group 4) was evaluated for oil, starch, protein and fatty acid composition mainly palmitic, stearic, oleic and linoleic acid. High oil content was observed in sweet corn samples which might be result of shriveled grain texture because of an increased embryo to kernel ratio. Individual fatty acids showed wide differences among different groups. A slightly higher amount of palmitic acid was reported in specialty maize as compared to normal maize. In contrast, stearic acid content was significantly low in high oil normal maize (56 %), QPM (36.2 %) and sweet corn (28.4 %) in comparison to low oil normal maize. Although no significant differences were observed for oleic acid between low oil normal and high oil normal maize, but sweet corn samples showed significantly reduced oleic acid compared to low oil normal maize. However, the most important observation was the higher content of linoleic acid in specialty maize (groups 2, 3 and 4) as compared to low oil normal maize. Further, the ratio of MUFA/PUFA was also discussed. It was concluded that specialty maize possesses a better oil quality in comparison to low oil normal maize.
Effect of single‐oocyte culture system on in vitro maturation and developmental competence in mice
Authors: Nishio Manami , Hoshino Yumi , Tanemura Kentaro , Sato Eimei 
Published: February 2014

AbstractPurposeTo investigate whether single‐culture systems influence the quality of in vitro‐matured oocytes, we examined the maturation and developmental competence of oocytes obtained by grouped in vitro maturation (IVM) or single IVM.MethodsIn vitro‐matured oocytes were obtained using the culture drop (CD) method for the grouped IVM experiments, and the CD and hanging drop (HD) method for the single IVM experiments. To evaluate oocyte developmental competence, we performed in vitro fertilization and culture, and counted the number of blastocysts. To evaluate the oocyte cytoplasmic maturation, we measured the maturation promoting factor (MPF) expression levels.ResultsOocytes cultured singly had lower maturity and developmental competence than the grouped IVM oocytes. However, enhanced oocyte fertility and blastocyst quality was achieved by the HD single IVM method. Additionally, the MPF activity level increased in all culture methods, compared to the control; however, it lagged behind nuclear maturation.ConclusionsThese results suggest that the HD method is efficient for single IVM.
Prenatal diagnostic testing among women referred for advanced maternal age in Beijing, 2001–2012
Authors: Ma Jingmei , Hong Pan , Fu Jie , Yu Li , Yang Huixia 
Published: February 2014

AbstractObjectiveTo determine the proportion of women with advanced maternal age (AMA) undergoing amniocentesis and assess the recommended indication of 35 years or older in China.MethodsData were retrospectively evaluated from 9641 patients who underwent diagnostic prenatal amniocentesis in Beijing, China, between January 2001 and December 2012. Maternal age, indication for testing, and karyotype data were collected. Patients referred for AMA were stratified in 2 ways: 35–37 years, 38–40 years, and 41 years or older; and indication of AMA alone or combined with other screening. Outcomes and safety performance were compared among the groups.ResultsFrom 2001 to 2012, the annual rate of amniocentesis and the proportion of AMA‐related indications increased (P< 0.01). Overall, 82 abnormalities were detected. In the AMA group, the spontaneous abortion rate was 0.5% (22/4748). The positive predictive value (PPV) of AMA alone was 0.5% for women aged 35–37 years. Only among women aged 41 years or older was the PPV of AMA alone better than that of AMA plus other indications (2.3% vs 1.5%, respectively).ConclusionThe PPV of 35 years or older did not offset the risk of spontaneous abortion. AMA alone should not be used as an indication for amniocentesis especially among women aged 35–40 years.