bluuebunny/crossref_metadata_2025_split huggingface dataset:
Recent Developments in Asymmetric Organocatalytic Domino Reactions
Authors: Pellissier Hélène 
Published: February 2012

AbstractSince about the year 2000, the research area of asymmetric organocatalysis has grown rapidly to become one of the most fascinating and current fields in organic chemistry. In the last years, asymmetric domino reactions have widely benefited from this fast‐growing field, as exemplified by the development of an explosive number of novel and powerful asymmetric organocatalytic domino processes, which allowed the easy construction of complex chiral molecular architectures from simple materials with high yields and very often remarkable enantioselectivities in a metal‐free environment. Indeed, the possibility to join two or more organocatalytic reactions in one asymmetric domino process has become a challenging goal for chemists, due to several advantages from economical and environmental points of view, avoiding costly protecting groups and time‐consuming purification procedures after each step, for example. This review aims to update the latest developments of this hot and fascinating field, covering the literature since the beginning of 2009.    Abbreviations:Ac: acetyl; Ar: aryl; BDHP: 1,1′‐binaphth‐2,2′‐diyl hydrogen phosphate; BA: Brønsted acid; BINAPO: 2‐diphenylphosphino‐2′‐diphenylphosphinyl‐1,1′‐binaphthalene; BINOL: 1,1′‐bi‐2‐naphthol; Boc:tert‐butoxycarbonyl; Bn: benzyl; Bu: butyl; Bz: benzoyl; CSA: camphorsulfonic acid; Cy: cyclohexyl; Cbz: benzyloxycarbonyl; DABCO: 1,4‐diazabicyclo[2.2.2]octane; DBU: 1,8‐diazabicyclo[5.4.0]undec‐7‐ene; DCE: dichloroethane;de: diastereomeric excess; DFT: density functional theory; DHQ: hydroquinine; DHQD: dihydroquinidine; DIPEA: diisopropylethylamine; DKR: dynamic kinetic resolution; DMAD: dimethyl acetylenedicarboxylate; E: electrophile;ee: enantiomeric excess; ESI: electrospray ionization; Et: ethyl; Fu: furyl; Hept: heptyl; Hex: hexyl; HOMO: highest occupied molecular orbital; IBX:o‐iodoxybenzoic acid; LB: Lewis base; LUMO: lowest unoccupied molecular orbital; Me: methyl; MOM: methoxymethyl; Mes: mesyl; MS: mass spectroscopy; MTBE: methyltert‐butyl ether; NADH: nicotinamide adenine dinucleotide; Naph: naphthyl; NHC: N‐heterocyclic carbene; NMM:N‐methylmorpholine; NMP:N‐methylpyrrolidinone; Ns: nosyl; Nu: nucleophile; Oct: octyl; PCC: pyridinium chlorochromate; Pent: pentyl; PFBA: pentafluorobenzoic acid; Ph: phenyl; PMB:para‐methoxybenzyl; Pr: propyl; Py: pyridine; r.t.: room temperature; TBA: tribromoacetic acid; TBS:tert‐butyldimethylsilyl; TCBA: 2,4,6‐trichlorobenzoic acid; TES: triethylsilyl; TFA: trifluoroacetic acid; THF: tetrahydrofuran; Thio: thiophene; TMEDA: tetramethylethylenediamine; TMS: trimethylsilyl; Tol: tolyl; Ts: 4‐toluenesulfonyl (tosyl).
Body image concerns and reduced breastfeeding duration in primiparous overweight and obese women
Authors: Hauff Laura E. , Demerath Ellen W. 
Published: February 2012

AbstractObjectives:To test differences in breastfeeding duration by prepregnant maternal weight status, and determine whether body image concerns mediate any differences.Methods:A prospective longitudinal cohort of primiparous women was followed from pregnancy to, at minimum, 6 months postpartum. Questionnaire responses on body concerns were obtained during pregnancy and at 4 months postpartum. Kaplan‐Meier curves compared breastfeeding duration in overweight/obese and normal weight groups. Cox proportional hazard regression was used to determine whether body image variables mediated the relationship between maternal weight and duration.Results:Although intended duration was similar between groups, overweight/obese women had a shorter median duration of any breastfeeding (38.6 weeks) compared to normal weight women (48.9 weeks) (P< 0.01) and they experienced higher risk of breastfeeding cessation over the entire first year postpartum [hazard risk (HR) = 1.43; confidence interval (CI) = 1.02–2.01;P< 0.05]. Overweight/obese women reported lack of body comfort/confidence postpartum more frequently than normal BMI women (P< 0.01). Lack of body comfort/confidence postpartum was negatively associated with duration after adjusting for maternal BMI (P= 0.01). Thus, the effect of BMI on duration was reduced by this variable (HR = 1.31; CI = 0.93, 1.86;P= 0.13), suggesting mediation.Conclusions:Women with high prepregnant BMI have reduced lactation duration that is mediated by lack of comfort/confidence with one's body. Further research into the interplay between body image, weight status, and breastfeeding outcomes may point to behavioral targets amenable to intervention and modification that may in turn improve breastfeeding outcomes for overweight/obese women and their infants. Am. J. Hum. Biol. 2012. © 2012 Wiley Periodicals, Inc.
Physical activity, cardio‐respiratory fitness, and metabolic traits in rural mexican tarahumara
Authors: Christensen Dirk Lund , Alcalá‐Sánchez Imelda , Leal‐Berumen Irene , Conchas‐Ramirez Miguel , Brage Soren 
Published: February 2012

AbstractObjectives: To study the association between physical activity energy expenditure (PAEE) and cardio‐respiratory fitness (CRF) with key metabolic traits and anthropometric measures in the Tarahumara of Mexico.Methods: A cross‐sectional study was carried out in five rural communities in Chihuahua, México including 64 adult Tarahumara, mean (SD) age 40.7 (12.9) years. Using a combined accelerometer and heart rate sensor, PAEE was measured over three consecutive days and nights and a sub‐maximal step test was carried out in order to (1) calibrate heart rate at the individual level and (2) to estimate CRF. Random blood glucose level and resting blood pressure (BP) were measured with standard anthropometrics.Results: Mean (SD) PAEE was 71.2 (30.3) kJ kg−1 day−1 and CRF was 36.6 (6.5) mlO2 min−1 kg−1. Mean (SD) glucose was 127.9 (32.4) mg/dl, with 3.3% having diabetes. Mean (SD) systolic and diastolic BP was 122 (20.8) and 82 (14.8) mm Hg, respectively, with 28.1% having hypertension. Mean body mass index was 27.5 (4.2) kg m−2, with 71.9% being overweight. Following adjustment for age and sex, weak inverse associations were observed between PAEE and systolic BP (β = −0.20, P = 0.27) and diastolic BP (β = −0.16, P = 0.23); and between CRF and systolic BP (β = −0.51, P = 0.14) and diastolic BP (β = −0.53, P = 0.06). The inverse associations with glucose were also weak and not statistically significant for neither PAEE (β = −0.01, P = 0.63) nor CRF (β = −0.05, P = 0.27).Conclusions: This study suggests high levels of overweight and hypertension in the Tarahumara, and points to fitness and physical activity as potential intervention targets although findings should be confirmed in larger samples. Am. J. Hum. Biol. 2012. © 2012 Wiley Periodicals, Inc.
Extreme behavioral lateralization and the remodeling of the distal humerus
Authors: Ozener Baris 
Published: February 2012

AbstractObjectives:The effects of extreme behavioral lateralization (i.e., extreme handedness) on the epicondylar breadth are poorly understood. This study was conducted in order to determine the effects of high levels of right‐ and left‐handedness on epicondyle of the humerus.Methods:Elbow width of 186 healthy male university students who completed their physical development (extreme left handed = 92, mean age = 18.67, SD = 0.61; extreme right handed = 94, mean age = 18.55, SD = 0.58) were measured with 0.01 mm sensitivity and Edinburgh Handedness Inventory was applied to determine the handedness of the individuals. Participants with scores of +100 were designated as extreme right‐handers, and participants with scores of −100 were designed as extreme left‐handers.Results:According to the findings, the degree of directional asymmetry was +1.22 (SD = 2.24) in the extreme right handed, whereas in extreme left handed −0.59 (SD = 1.74). The relative deviation percentage in the extreme right handed was 3.1% whereas 2.2% in the extreme left handed.Conclusions:It could be stated that extreme handedness has an influence on the asymmetry of epicondyle of the humerus; nevertheless, this effect is more significant in the extreme right handed. This is likely to result from the necessity for left‐handed people to adapt themselves to the conditions of a dominantly “right‐handed” world. Am. J. Hum. Biol. 2012. © 2012 Wiley Periodicals, Inc.
Microbial exposures in infancy predict levels of the immunoregulatory cytokine interleukin‐4 in filipino young adults
Authors: Tallman Paula Skye , Kuzawa Christopher , Adair Linda , Borja Judith B. , McDade Thomas W. 
Published: February 2012

AbstractObjectives:Infancy represents a window of development during which long‐term immunological functioning can be influenced. In this study, we evaluate proxies of microbial exposures in infancy as predictors of interleukin‐4 (IL‐4) in young adulthood. IL‐4 is an immunoregulatory cytokine that plays a role in the pathogenesis of atopic and allergic diseases.Methods:Data were obtained from 1,403 participants in the Cebu Longitudinal Health and Nutrition Survey, an ongoing population‐based study in the Philippines. Relationships between microbial and nutritional environments in infancy and plasma IL‐4 concentrations in adulthood were evaluated using tobit regression models.Results:Having older siblings and more episodes of respiratory illness in infancy significantly predicted lower concentrations of plasma IL‐4 in adulthood. Unexpectedly, more episodes of diarrheal illness in infancy were associated with higher IL‐4 in adulthood. Interactions between a composite household pathogen exposure score and the duration of exclusive breastfeeding approached significance. This interaction showed that the negative association between household pathogen exposure in infancy and adult IL‐4 was only significant for individuals who had been exclusively breastfed for a short duration of time. Finally, currently living in an urban household was unexpectedly, negatively associated with adult IL‐4. Associations were independent of early nutrition, socioeconomic status (SES), and urbanicity, as well as current measures of infection, body fat, SES, and smoking.Conclusions:This study builds on a growing body of literature demonstrating that early ecological conditions have long‐term effects on human biology by providing evidence that multiple proxies of microbial exposures in infancy are associated with adult IL‐4. Am. J. Hum. Biol. 2012. © 2012 Wiley Periodicals, Inc.
Rare‐Earth–Transition‐Metal Organic–Inorganic Hybrids Based on Keggin‐type Polyoxometalates and Pyrazine‐2,3‐dicarboxylate
Authors: Zhang Shaowei , Zhao Junwei , Ma Pengtao , Niu Jingyang , Wang Jingping 
Published: February 2012

AbstractFive rare‐earth–transition‐metal (RE–TM) heterometal organic–inorganic hybrids based on Keggin‐type silicotungstates and mixed ligands H2pzda (pzda=pyrazine‐2,3‐dicarboxylate) and en (en=ethylenediamine) (enH2)[Cu(en)2(H2O)]2{[Cu(en)2][Cu(en)2(H2O)][(α‐SiW11 O39)RE(H2O)(pzda)]}2⋅n H2O (n≈4; RE=YIII (1), DyIII (2), YbIII (3), and LuIII (4)) and [Cu(en)2(H2O)]2{[Cu(en)2]2[Cu(pzda)2][(α‐H2SiW11O39)Ce(H2O)]2}⋅n H2O (5; n≈8) have been hydrothermally synthesized and structurally characterized. Compounds 1–5 all contain the dimeric mono‐RE substituted Keggin [RE(α‐SiW11O39)]210− subunits linked by H2pzda ligands. Interestingly, 1–4 exhibit discrete structures, in which the H2pzda ligand acts as a tetradentate ligand to bind the RE and Cu cations, whereas 5 displays a 1D double‐chain architecture, in which the H2pzda ligand adopts a new pentadentate mode to connect the Ce and Cu cations. To our knowledge, 1–5 represent the first monovacant Keggin‐type silicotungstates containing both RE–TM heterometals and mixed ligands. The luminescence of 2 is derived from the combination of the DyIII cations and H2pzda ligands, whereas the luminescence properties of 1 and 3–5 are attributable to the H2pzda ligands.
The establishment of the duplex real‐time RT‐PCR assay for the detection of CD44v6 in pancreatic cancer patients and clinical application
Authors: Zhou Gang , Chiu David , Qin Dajiang , Niu Lizhi , Cai Jinlei , He Lihua , Huang Wenhao , Xu Kecheng 
Published: February 2012

AbstractCell adhesion molecule CD44v6 has been found to be associated with the progression and metastasis of numerous cancers. In this study, a novel duplex real‐time quantitative reverse‐transcription PCR (qRT‐PCR) assay was developed to quantitatively detect the CD44v6 gene expression in pancreatic cancer patients. The primers and probes of CD44v6 and β‐actin genes were designed and standard curve of the duplex qRT‐PCR was constructed by optimizing the reaction conditions. The specificity and reproducibility of this assay were satisfactory and the detection limit was 100 copies, which was 10 times more sensitive than the conventional RT‐PCR assay. This assay was also used to detect the expression levels of CD44v6 messenger RNA in peripheral blood mononuclear cell in 37 pancreatic cancer patients and 12 healthy people. The results showed that 37 clinical samples were tested positive by the duplex qRT‐PCR compared with only 30 by the conventional RT‐PCR. The levels of CD44v6 expression showed significant correlation with sex, tumor size, tumor differentiation, clinical stage, lymph node, and liver metastasis (P < 0.05). Compared with the control group, CD44v6 levels in patients prior and 10 days post cryosurgery were significantly increased (P < 0.05) but had no significant change in those 1 month post cryosurgery (P > 0.05). The duplex qRT‐PCR assay may provide a useful tool for the evaluation of prognosis and curative effect of pancreatic cancer.
Risk of anastomotic leakage with non-steroidal anti-inflammatory drugs in colorectal surgery
Authors: Gorissen K J , Benning D , Berghmans T , Snoeijs M G , Sosef M N , Hulsewe K W E , Luyer M D P 
Published: February 2012

Abstract

Background
With the implementation of multimodal analgesia regimens in fast-track surgery programmes, non-steroidal anti-inflammatory drugs (NSAIDs) are being prescribed routinely. However, doubts have been raised concerning the safety of NSAIDs in terms of anastomotic healing.

Methods
Data on patients who had undergone primary colorectal anastomosis at two teaching hospitals between January 2008 and December 2010 were analysed retrospectively. Exact use of NSAIDs was recorded. Rates of anastomotic leakage were compared between groups and corrected for known risk factors in both univariable and multivariable analyses.

Results
A total of 795 patients were divided into four groups according to NSAID use: no NSAIDs (471 patients), use of non-selective NSAIDs (201), use of selective cyclo-oxygenase (COX) 2 inhibitors (79), and use of both selective and non-selective NSAIDs (44). The overall leak rate was 9·9 per cent (10·0 per cent for right colonic, 8·7 per cent for left colonic and 12·4 per cent for rectal anastomoses). Known risk factors such as smoking and use of steroids were not significantly associated with anastomotic leakage. Stapled anastomosis was identified as an independent predictor of leakage in multivariable analysis (odds ratio (OR) 2·22, 95 per cent confidence interval 1·30 to 3·80; P = 0·003). Patients on NSAIDs had higher anastomotic leakage rates than those not on NSAIDs (13·2 versus 7·6 per cent; OR 1·84, 1·13 to 2·98; P = 0·010). This effect was mainly due to non-selective NSAIDs (14·5 per cent; OR 2·13, 1·24 to 3·65; P = 0·006), not selective COX-2 inhibitors (9 per cent; OR 1·16, 0·49 to 2·75; P = 0·741). The overall mortality rate was 4·2 per cent, with no significant difference between groups (P = 0·438).

Conclusion
Non-selective NSAIDs may be associated with anastomotic leakage.
Real‐time monitoring of shake flask fermentation and off gas using triple disposable noninvasive optical sensors
Authors: Ge Xudong , Rao Govind 
Published: February 2012

AbstractBioprocess development is a data‐driven process requiring a large number of experiments to be conducted under varying conditions. Small‐scale upstream bioprocess development is often performed in shake flasks because they are inexpensive and can be operated in parallel. However, shake flasks are often not equipped to accurately monitor critical process parameters such as pH, dissolved oxygen, and CO2 concentrations. Therefore, there is no definitive information on oxygen supply of growing cells, CO2 formation, and pH changes. Here we describe several shake flask fermentations where all three parameters are monitored by disposable noninvasive optical sensors. The sensitive element of these sensors is a thin, luminescent patch affixed inside the flask. Small electronic devices for excitation and fluorescence detection are positioned outside the shake flask for noninvasive monitoring. By measuring the process parameters throughout the course of the E. coli fermentations, we obtain information that is not routinely available in shake flask fermentations. For example, for cultures with only a few millimeters liquid depth, oxygen limitation can occur at relatively low agitation speeds. Under certain conditions oscillations in dissolved oxygen can occur. An increase in shaker speed and a decrease in culture volume can increase the oxygen availability and reduce the duration of oxygen limitation. © 2012 American Institute of Chemical Engineers Biotechnol. Prog.,, 2012
Real‐time density‐based crowd simulation
Authors: van Toll Wouter G. , Cook Atlas F. , Geraerts Roland 
Published: February 2012

ABSTRACTVirtual characters in games and simulations often need to plan visually convincing paths through a crowded environment. This paper describes how crowd density information can be used to guide a large number of characters through a crowded environment. Crowd density information helps characters avoid congested routes that could lead to traffic jams. It also encourages characters to use a wide variety of routes to reach their destination. Our technique measures the desirability of a route by combining distance information with crowd density information. We start by building a navigation mesh for the walkable regions in a polygonal two‐dimensional (2‐D) or multilayered three‐dimensional (3‐D) environment. The skeleton of this navigation mesh is the medial axis. Each walkable region in the navigation mesh maintains an up‐to‐date density value. This density value is equal to the area occupied by all the characters inside a given region divided by the total area of this region. These density values are mapped onto the medial axis to form a weighted graph. An A* search on this graph yields a backbone path for each character, and forces are used to guide the characters through the weighted environment. The characters periodically replan their routes as the density values are updated. Our experiments show that we can compute congestion‐avoiding paths for tens of thousands of characters in real‐time. Copyright © 2012 John Wiley & Sons, Ltd.
An Experimental Study on the Effect of Substituents on Aromatic–Aromatic Interactions in Dithia[3,3]‐metaparacyclophanes
Authors: Xia Jian Long , Liu Sheng Hua , Cozzi Franco , Mancinelli Michele , Mazzanti Andrea 
Published: February 2012

AbstractSimple model systems based on the 2,11‐dithia[3,3]‐metaparacyclophane skeleton were synthesized to study the effects of substituents on the intramolecular aromatic–aromatic interactions between benzene rings. X‐ray crystallography established that, in their more stable conformations, these metaparacyclophanes featured partially overlapping aromatic rings (interplanar distances of about 3.5 Å), with the planes of the aromatic systems arranged in a slightly tilted disposition (interplanar angles in the range 5–19°). Calculations showed that these derivatives underwent topomerization by flipping of the meta‐substituted ring over the para‐substituted one, a process in which the two rings adopted a continuum of edge‐to‐face dispositions, including an orthogonal one, which were less stable than the starting face‐to‐face arrangement. The energy barriers to the isomerization process were experimentally determined by variable‐temperature NMR spectroscopy, by using an internal temperature standard to assess even minor differences in energy (relative experimental error: (±0.1 kJ mol−1). The variation in the barriers as a function of the different substituents on the interacting ring was small and apparently unrelated to the effect of the substituents on the polarity of the π‐systems. An explanation based on the charge‐penetration effect seemed more‐suitable to rationalize the observed trends in the barriers.
ChemInform Abstract: A Study of the Al‐Rich Part of the Al—Ni—Pt Alloy System.
Authors: Grushko B. , Kapush D. , Meshi L. 
Published: February 2012

AbstractThe aluminum rich (50—100 at.% Al) part of the title system at 790, 900, and 1000 °C is investigated by powder XRD, SEM, and TEM.
ChemInform Abstract: Syntheses and Crystal Structures of the closo‐Borate M[B8H9] (M: [PPh4]+ and [N(n‐Bu4)]+).
Authors: Schlueter Florian , Bernhardt Eduard 
Published: February 2012

AbstractThe [B8H8]2‐ and [B8H9]‐ ions are characterized by NMR spectroscopy, single crystal XRD, and DFT calculations.
ChemInform Abstract: Laccase‐Catalyzed Stereoselective Oxidative Ring Opening of 2,5‐Dialkylfurans into 2‐Ene‐1,4‐diones Using Air as an Oxidant.
Authors: Asta Chimene , Conrad Juergen , Mika Sabine , Beifuss Uwe 
Published: February 2012

AbstractThe laccase‐catalyzed ring cleavage of symmetrically and asymmetrically substituted 2,5‐dialkylfurans (I) yields (Z)‐enediones (II) in a diastereoselective manner.
ChemInform Abstract: Efficient Synthesis of Carbonyl Compounds: Oxidation of Azides and Alcohols Catalyzed by Vanadium Pentoxide in Water Using tert‐Butylhydroperoxide.
Authors: Alagiri Kaliyamoorthy , Prabhu Kandikere Ramaiah 
Published: February 2012

AbstractBenzylic azides are conveniently oxidized to the corresponding acids or ketones.
ChemInform Abstract: Polymer‐Mounted N3=P(MeNCH2CH2)3N: A Green, Efficient and Recyclable Catalyst for Room‐Temperature Transesterifications and Amidations of Unactivated Esters.
Authors: Chintareddy Venkat Reddy , Ho Hung‐An , Sadow Aaron D. , Verkade John G. 
Published: February 2012

AbstractThe processes are investigated in the presence of azaphosphatranes (I) and (II).
ChemInform Abstract: Synthesis of Thiol Esters by the Reaction of Ricinoleic Acid with Thiols under Solvent‐Free Conditions.
Authors: Lara Renata G. , Rodrigues Dielson C. , Mendes Samuel R. , Panatieri Rodrigo B. , Jacob Raquel G. , Alves Diego , Lenardao Eder J. , Perin Gelson 
Published: February 2012

AbstractThe synthesis of thiol esters (III) and (VI) from aliphatic and aromatic carboxylic acids and aliphatic as well as aromatic thiols is studied.
ChemInform Abstract: An Efficient Catalytic Method for Fulvene Synthesis.
Authors: Coskun Necdet , Erden Ihsan 
Published: February 2012

AbstractThe pyrrolidine‐catalyzed condensation of carbonyl compounds with cyclopentadiene (I) proceeds readily for a wide diversity of aldehydes and ketones in methanol/water mixtures, affording the product fulvenes in reasonable yields simply by vacuum filtration.
ChemInform Abstract: Cobalt‐Catalyzed 1,4‐Hydrobutadienylation of 1‐Aryl‐1,3‐dienes with 2,3‐Dimethyl‐1,3‐butadiene.
Authors: Bohn Martin A. , Schmidt Anastasia , Hilt Gerhard , Dindaroglu Mehmet , Schmalz Hans‐Guenther 
Published: February 2012

AbstractA new C—C bond formation is presented in the Co‐catalyzed reaction of arylbutadienes, e.g. (I), with dimethylbutadiene (II).
ChemInform Abstract: Lithium Perchlorate—Nitromethane‐Promoted Alkylation of Anilines with Arylmethanols.
Authors: Zhou Jun , Mao Hai‐Feng , Wang Lu , Zou Jian‐Ping , Zhang Wei 
Published: February 2012

AbstractThe selective formation of N‐alkylated anilines (III), double Friedel—Crafts alkylation products such as (IV) and (VI) or N—C‐alkylated compound (V) is achieved by changing the temperature, the stoichiometry of reactants, and the time.