bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stable, high‐affinity streptavidin monomer for protein labeling and monovalent biotin detection
Authors: Lim Kok Hong , Huang Heng , Pralle Arnd , Park Sheldon 
Published: July 2012

AbstractThe coupling between the quaternary structure, stability and function of streptavidin makes it difficult to engineer a stable, high affinity monomer for biotechnology applications. For example, the binding pocket of streptavidin tetramer is comprised of residues from multiple subunits, which cannot be replicated in a single domain protein. However, rhizavidin from Rhizobium etli was recently shown to bind biotin with high affinity as a dimer without the hydrophobic tryptophan lid donated by an adjacent subunit. In particular, the binding site of rhizavidin uses residues from a single subunit to interact with bound biotin. We therefore postulated that replacing the binding site residues of streptavidin monomer with corresponding rhizavidin residues would lead to the design of a high affinity monomer useful for biotechnology applications. Here, we report the construction and characterization of a structural monomer, mSA, which combines the streptavidin and rhizavidin sequences to achieve optimized biophysical properties. First, the biotin affinity of mSA (Kd = 2.8 nM) is the highest among nontetrameric streptavidin, allowing sensitive monovalent detection of biotinylated ligands. The monomer also has significantly higher stability (Tm = 59.8°C) and solubility than all other previously engineered monomers to ensure the molecule remains folded and functional during its application. Using fluorescence correlation spectroscopy, we show that mSA binds biotinylated targets as a monomer. We also show that the molecule can be used as a genetic tag to introduce biotin binding capability to a heterologous protein. For example, recombinantly fusing the monomer to a cell surface receptor allows direct labeling and imaging of transfected cells using biotinylated fluorophores. A stable and functional streptavidin monomer, such as mSA, should be a useful reagent for designing novel detection systems based on monovalent biotin interaction. Biotechnol. Bioeng. 2013; 110: 57–67. © 2012 Wiley Periodicals, Inc.
Re‐dispersion of Cobalt on a Model Fischer–Tropsch Catalyst During Reduction–Oxidation–Reduction Cycles
Authors: Hauman M. M. , Saib A. , Moodley D. J. , du Plessis E. , Claeys M. , van Steen E. 
Published: July 2012

AbstractReduction–oxidation–reduction treatment is employed to regenerate cobalt Fischer–Tropsch synthesis catalysts. Reduction–oxidation–reduction cycles on a model supported‐cobalt Fischer–Tropsch catalyst showed that hollow‐sphere formation occurs during the oxidation step, followed by the formation of a catalyst with an improved metal dispersion. It is deduced that the metal particles consist of both hexagonal close packed Co and face‐centered cubic Co. High‐pressure oxidation led to smaller cobalt oxide crystallites, resulting in a more facile reduction and an increase in metal surface area. Hence, oxidative regeneration is an attractive method to improve the dispersion of cobalt metal on a sintered deactivated catalyst. However, metallic cobalt crystallites may become too small after regeneration, and the intrinsic activity per unit surface area in the Fischer–Tropsch synthesis may drop.
Insights into the Temperature‐Dependent “Breathing” of a Flexible Fluorinated Metal–Organic Framework
Authors: Fernandez Carlos A. , Thallapally Praveen K. , McGrail B. Peter 
Published: July 2012

AbstractThe framework expansion and contraction upon carbon dioxide uptake was studied in a partially fluorinated metal–organic framework, FMOF‐2. The results show framework expansion and contraction (breathing) as a function of pressure and temperature. Even at temperatures as low as −30 °C, two phase transitions seem to take place with a pressure step (corresponding to the second transition) that is greatly dependent on temperature. This behavior is described by the model proposed by Coudert and co‐workers showing that the material seems to undergo two phase transitions that are temperature‐dependent. The isosteric heats of adsorption at high pressures show a minimum that is concurrent with the region of CO2 loadings where the second pressure step occurs. It was deduced that these lower enthalpy values are a consequence of the energy cost related to the expansion or reopening of the framework. Lastly, the large and reversible breathing behavior may be a product of the combination of the high elasticity of zinc (II) coordination and the apparent high flexibility of the V‐shaped organic building block.
Induced growth of Pb0.97La0.02(Zr0.66Sn0.27Ti0.07)O3 antiferroelectric single crystals with a platinum wire
Authors: Yang Zi , Li Qiang , Li Yuanyuan , Wang Lin 
Published: July 2012

AbstractRelaxor antiferroelectric (Pb,La)(Zr,Sn,Ti)O3 (PLZST) with the composition near the morphotropic phase boundary shows excellent electrical properties. However, the crystal growth of PLZST is limited by the incongruent melting of the materials. Crystal growth of PLZST was induced by a platinum wire in the flux solution with 50 wt% PbO‐PbF2‐B2O3 as a solvent. The obtained PLZST single crystals are optical transparent with light yellow color. The size of the crystals in regular rectangular shape varies from 0.5 mm to 1 mm. The PLZST single crystals exhibit tetragonal phase structure. The element contents of the crystals were measured by inductively coupled plasma atomic emission spectrometry. The results show that the composition of as‐grown crystals is a little bit deviated from the starting composition. The single crystals show two dielectric peaks at 115 °C and 182 °C, corresponding to antiferroelectric‐ferroelectric and ferroelectric‐paraelectric phase transitions. The dielectric data of as‐grown crystals indicate there is typical relaxor behavior near 182 °C. The value of relaxor factor n is 1.49642.
Analytical model for approximating node throughputs in wireless mesh networks
Authors: Hunchangsith Konglit , Bialkowski Marek E. , Portmann Marius , Tan Wee Lum 
Published: July 2012

SUMMARYThis paper describes an analytical model and an associated algorithm for assessing the throughputs of each host in wireless mesh networks (WMNs). It provides a framework for studying WMNs, particularly when the performance and parameters in multiple protocol layers have to be jointly evaluated and optimized. From the point of the implementation, a simple recursive formula with N − 1 iterations is used to obtain the throughput performance of N node WMNs. The produced expressions offer insights into understanding the performance of the individual nodes without referring to a specific medium access control layer or physical layer technology. The model serves as a general tool for capturing the characteristics of the WMNs. Using the model, the complexity of cross‐layer studies is reduced, thus allowing researchers to focus on the modelling of other associated layers. The paper explains the rationale behind the model and provides examples of scenarios for which it is suitable. It is validated using discrete event simulations in the OPNET network simulator. Copyright © 2012 John Wiley & Sons, Ltd.
Cooperative Metal–Ligand‐Induced Properties of Heteroleptic Copper(I) Xanthate/Dithiocarbamate PPh3 Complexes
Authors: Rajput Gunjan , Singh Vikram , Singh Santosh K. , Prasad Lal B. , Drew Michael G. B. , Singh Nanhai 
Published: July 2012

AbstractFour new heteroleptic mononuclear complexes, [Cu(PPh3)2L1](1) {L1 = (C9H11O2CS2–), [2‐(4‐methoxyphenyl)ethyl]xanthate}, [Cu(PPh3)2L2] (2) [L2 = (C6H7OCS2–), benzylxanthate], [Cu(PPh3)2L3] (3) [L3 = (C5H9OCS2–), (cyclobutylmethyl)xanthate] and [Cu(PPh3)2L4] (4) [L4 = (NC13H13NCS2–), N‐benzyl‐N‐(4‐pyridylmethyl)dithiocarbamate], have been synthesized and characterized by using microanalysis, IR, UV/Vis, 1H, 13C and 31P NMR spectroscopy and X‐ray crystallography; their photoluminescent behaviour and molecular electrical conductivity have been investigated. CuI possesses four‐coordinate distorted tetrahedral geometry in all the complexes. All are weakly conducting and exhibit semiconductor behaviour in the studied 303–363 K temperature range. Complex 4 shows striking luminescent behaviour emitting bluish green light at 480 nm in CH2Cl2 solution at room temperature.
Fascinating Diazirinone: A Violet Gas (Eur. J. Inorg. Chem. 21/2012)
Authors: Zeng Xiaoqing , Beckers Helmut , Willner Helge , Stanton John F. 
Published: July 2012

AbstractThe cover picture shows the decay of high‐energy diazirinone (cyclic N2CO). At room temperature this violet gas has a half life of 30 h. The IR, Raman, and electronic spectra were analyzed, and the photochemistry was studied in a solid argon matrix at 16 K. Details are discussed in the article by X. Zeng, J. F. Stanton et al. on p. 3403 ff. magnified image
Survey of Synthetic Approaches to Natural (Peyssonenynes) and Unnatural Acetoxyenediynes
Authors: García‐Domínguez Patricia , Alvarez Rosana , de Lera Ángel R. 
Published: July 2012

AbstractFour convergent synthetic approaches to acetoxyenediynes have been explored to gain access to peyssonenynes A and B, which are natural products isolated from the red alga Peyssonelia caulifera. After optimization of the routes with a palmitic acid based model system, the synthesis of the peyssonenynes was completed by using, as the key steps, 1) Ni/Cu co‐catalyzed cross‐coupling of terminal alkynes, 2) Sonogashira cross‐coupling, 3) the addition of a diynyl anion to a Weinreb amide, and 4) the previously reported Cadiot–Chodkiewicz cross‐coupling reaction. Because bulky amide bases stereoselectively provided the (E)‐ and (Z)‐acetoxyenynes from the precursor ynones, the cross‐coupling routes to obtaining the acetoxyenediynes by using these stereochemically homogeneous intermediates are comparable to the alternatives in which enolacetate formation of the acetoxyenediyne motif takes place at a late stage in the synthesis.
Extension of direct displacement‐based design methodology for bridges to account for higher mode effects
Authors: Kappos Andreas J. , Gkatzogias Konstantinos I. , Gidaris Ioannis G. 
Published: July 2012

SUMMARYAn improvement is suggested to the direct displacement‐based design (DDBD) procedure for bridges to account for higher mode effects, the key idea being not only the proper prediction of a target‐displacement profile through the effective mode shape method (wherein all significant modes are considered), but also the proper definition of the corresponding peak structural response. The proposed methodology is then applied to an actual concrete bridge wherein the different pier heights and the unrestrained transverse displacement at the abutments result in an increased contribution of the second mode. A comparison between the extended and the ‘standard’ DDBD is conducted, while further issues such as the proper consideration of the degree of fixity at the pier's top and the effect of the deck's torsional stiffness are also investigated. The proposed methodology and resulting designs are evaluated using nonlinear response‐history analysis for a number of spectrum‐compatible motions. Unlike the ‘standard’ DDBD, the extended procedure adequately reproduced the target‐displacement profile providing at the same time a good estimate of results regarding additional design quantities such as yield displacements, displacement ductilities, etc., closely matching the results of the more rigorous nonlinear response‐history analysis. However, the need for additional iterations clearly indicates that practical application of the proposed procedure is feasible only if it is fully ‘automated’, that is, implemented in a software package. Copyright © 2012 John Wiley & Sons, Ltd.
An efficient very large eddy simulation model for simulation of turbulent flow
Authors: Han Xingsi , Krajnović Siniša 
Published: July 2012

SUMMARYAmong the various hybrid methodologies, Speziale's very large eddy simulation (VLES) is one that was proposed very early. It is a unified simulation approach that can change seamlessly from Reynolds Averaged Navier–Stokes (RANS) to direct numerical simulation (DNS) depending on the numerical resolution. The present study proposes a new improved variant of the original VLES model. The advantages are achieved in two ways: (i) RANS simulation can be recovered near the wall which is similar to the detached eddy simulation concept; (ii) a LES subgrid scale model can be reached by the introduction of a third length scale, that is, the integral turbulence length scale. Thus, the new model can provide a proper LES mode between the RANS and DNS limits. This new methodology is implemented in the standard k − ϵ model. Applications are conducted for the turbulent channel flow at Reynolds number of Reτ = 395, periodic hill flow at Re = 10,595, and turbulent flow past a square cylinder at Re = 22,000. In comparison with the available experimental data, DNS or LES, the new VLES model produces better predictions than the original VLES model. Furthermore, it is demonstrated that the new method is quite efficient in resolving the large flow structures and can give satisfactory predictions on a coarse mesh. Copyright © 2012 John Wiley & Sons, Ltd.
Sinonasal mucosal melanoma: Molecular profile and therapeutic implications from a series of 32 cases
Authors: Turri–Zanoni Mario , Medicina Daniela , Lombardi Davide , Ungari Marco , Balzarini Piera , Rossini Cristina , Pellegrini Wilma , Battaglia Paolo , Capella Carlo , Castelnuovo Paolo , Palmedo Gabriele , Facchetti Fabio , Kutzner Heinz , Nicolai Piero , Vermi William 
Published: July 2012

AbstractBackgroundPrimary sinonasal mucosal melanomas are aggressive tumors with a poor clinical control by current treatments, raising the urgent need of novel strategies.MethodsBy fluorescence in situ hybridization (FISH), direct sequencing, and immunohistochemistry, we investigate the spectrum of molecular abnormalities in a cohort of 32 cases of primary sinonasal mucosal melanomas.ResultsWe found that all primary sinonasal mucosal melanomas lack BRAF V600E mutation; in addition, they are characterized by somatic mutations of NRAS (22%) and KIT (12.5%), together with amplification of RREB1 (100%) and loss of MYB (76%). The large majority of cases showed KIT protein expression (96.9%). Among tumor suppressor genes, primary sinonasal mucosal melanomas showed loss of PTEN (48.1%) and p16/INK4a (55.2%). All tested cases showed expression of pAkt and pErk, suggesting a combined activation of PI3K/Akt and RAS‐mitogen‐activated protein kinase (MAPK) pathways.ConclusionsThis molecular fingerprint strongly argues against the clinical efficacy of BRAF‐inhibitors, but could candidate primary sinonasal mucosal melanomas to therapeutic strategies targeting RAS and KIT mutations or inhibiting PI3K‐Akt‐mTOR pathway. Head Neck, 2013
Cooperative Asymmetric Catalysis Using Thioamides toward Truly Practical Organic Syntheses
Authors: Kumagai Naoya , Shibasaki Masakatsu 
Published: July 2012

AbstractAsymmetric catalysis has established its unwavering position in organic chemistry as a particularly efficient strategy for the production of enantiomerically enriched compounds. For a truly practical synthetic protocol, however, asymmetric catalysis must be endowed with high atom economy and sustainability. Cooperative activation is a powerful strategy to drive efficient asymmetric catalysis without the use of stoichiometric activating reagents, leading to asymmetric catalysis with minimum waste production. This review summarizes the utility of thioamides as an emerging functional group class in cooperative asymmetric catalysis. Soft Lewis acid/hard Brønsted base cooperative catalysts, in which thioamides serve as either electrophiles or pronucleophiles, promote asymmetric CC bond‐forming reactions with perfect atom economy.
Combined Enzyme and Transition‐Metal Catalysis for Dynamic Kinetic Resolutions
Authors: Marcos Rocío , Martín‐Matute Belén 
Published: July 2012

AbstractThe preparation of optically pure alcohols, axially chiral allenes, and amine derivatives by using enzymes and transition‐metal catalysts through dynamic kinetic resolution (DKR) is reviewed. After a general introduction into enzymatic kinetic resolutions and racemizations catalyzed by transition‐metal complexes, selected examples of DKRs are presented, from early work to more recent outstanding contributions, and also applications of this approach.
Evaluation of the GADD45α‐GFP GreenScreen HC assay for rapid and reliable in vitro early genotoxicity screening
Authors: Luzy Anne‐Pascale , Orsini Nicolas , Linget Jean‐Michel , Bouvier Guy 
Published: July 2012

ABSTRACTTwenty‐two of Galderma's proprietary compounds were tested in the GADD45α‐GFP ‘GreenScreen HC’ assay (GS), the SOS‐ChromoTest and the Mini‐Ames to evaluate GSs performance for early genotoxicity screening purposes. Forty more characterized compounds were also tested, including antibiotics: metronidazole, clindamycin, tetracycline, lymecycline and neomycin; and catecholamines: resorcinol mequinol, hydroquinone, one aneugen carbendazim, one corticoid dexamethasone, one peroxisome proliferator‐activated receptor rosiglitazone, one pesticide carbaryl and two further proprietary molecules with in vitro genotoxicity data. With proprietary molecules, this study concluded that the GS renders the SOS‐ChromoTest obsolete for in vitro screening. The GS confirmed all results of the Mini‐Ames test (100% concordance). Compared with the micronucleus test, the GS showed a concordance of 82%. With known compounds, the GS ranked the potency of positive results for catecholamines in accordance with other genotoxicity tests and showed very reproducible results. It confirmed positive results for carbendazim, for tetracycline antibiotics and for carbaryl. The GS produced negative results for metronidazole, a nitroreduction‐specific bacterial mutagen, for dexamethasone (a non‐genotoxic apoptosis inducer), for rosiglitazone (a GADD45γ promoter inducer) and for clindamycin and neomycin (inhibitors of macromolecular synthesis in bacteria). As such, the GS appears to be a reproducible, robust, specific and sensitive test for genotoxicity screening. Copyright © 2012 John Wiley & Sons, Ltd.
The transcription factor paired box-5 promotes osteoblastogenesis through direct induction of Osterix and Osteocalcin
Authors: Hinoi Eiichi , Nakatani Eri , Yamamoto Tomomi , Iezaki Takashi , Takahata Yoshifumi , Fujita Hiroyuki , Ishiura Ryo , Takamori Misa , Yoneda Yukio 
Published: July 2012

Abstract
Although skeletal abnormalities are seen in mice deficient of particular paired box (Pax) family proteins, little attention has been paid to their role in osteoblastogenesis so far. Here, we investigated the possible involvement of several Pax family members in mechanisms underlying the regulation of differentiation and maturation of osteoblasts. Among different Pax family members tested, Pax5 was not markedly expressed in murine calvarial osteoblasts before culture, but progressively expressed by osteoblasts under differentiation toward maturation. Immunoreactive Pax5 was highly detectable in primary cultured mature osteoblasts on immunoblotting and in osteoblastic cells attached to cancellous bone in mouse tibial sections on immunohistochemistry, respectively. Knockdown by small interfering RNA (siRNA) of endogenous Pax5 led to significant inhibition of the expression of Osteocalcin, and Osterix through deterioration of gene transactivation, in addition to a1(I)Collagen expression and alkaline phosphatase (ALP) staining, without affecting runt-related transcription factor-2 (Runx2) expression and cell viability in osteoblastic MC3T3-E1 cells. The introduction of Pax5 enhanced promoter activities of Osteocalcin and Osterix in a manner dependent on the paired domain in MC3T3-E1 cells. Putative Pax5 binding sites were identified in the 5′-flanking regions of mouse Osteocalcin and Osterix, whereas chromatin immunoprecipitation assay revealed the direct binding of Pax5 to particular regions of Osteocalcin and Osterix promoters in MC3T3-E1 cells. Overexpression of Pax5 significantly increased Osteocalcin, Osterix, and a1(I)Collagen expression, ALP activity, and Ca2+ accumulation, without affecting Runx2 expression, in MC3T3-E1 cells. In vertebrae of transgenic mice predominantly expressing Pax5 in osteoblasts, a significant increase was seen in the ratio of bone volume over tissue volume and the bone formation rate. These findings suggest that Pax5 could positively regulate osteoblastic differentiation toward maturation in vitro, in addition to promoting bone formation and remodeling in vivo, as one of the transcription factors essential for controlling osteoblastogenesis independently of Runx2. © 2012 American Society for Bone and Mineral Research.
Susceptibility genes for osteoporotic fracture in postmenopausal chinese women
Authors: Wang Chun , Zhang Zeng , Zhang Hao , He Jin-Wei , Gu Jie-Mei , Hu Wei-Wei , Hu Yun-Qiu , Li Miao , Liu Yu-Juan , Fu Wen-Zhen , Yue Hua , Ke Yao-Hua , Zhang Zhen-Lin 
Published: July 2012

Abstract
To identify the susceptibility genes for osteoporotic fracture in postmenopausal Chinese women, a two-stage case-control association study using joint analysis was conducted in 1046 patients with nontraumatic vertebra, hip, or distal radius fractures and 2303 healthy controls. First, 113 single-nucleotide polymorphisms (SNPs) in 16 potential osteoporosis candidate genes reported in recent genomewide association studies, meta-analyses studies, large-scale association studies, and functional studies were genotyped in a small-sample-size subgroup consisting of 541 patients with osteoporotic fractures and 554 healthy controls. Variants and haplotypes in SPTBN1, TNFRSF11B, CNR2, LRP4, and ESR1 that have been identified as being associated with osteoporotic fractures were further reanalyzed in the entire case-control group. We identified one SNP in TNFRSF11B (rs3102734), three SNPs in ESR1 (rs9397448, rs2234693, and rs1643821), two SNPs in LRP4 (rs17790156 and rs898604), and four SNPs in SPTBN1 (rs2971886, rs2941583, rs2941584, and rs12475342) were associated with all of the broadly defined osteoporotic fractures. The most significant polymorphism was rs3102734, with increased risk of osteoporotic fractures (odds ratio, 1.35; 95% confidence interval [CI], 1.17–1.55, Bonferroni p = 2.6 × 10−4). Furthermore, rs3102734, rs2941584, rs12475342, rs9397448, rs2234693, and rs898604 exhibited significant allelic, genotypic, and/or haplotypic associations with vertebral fractures. SNPs rs12475342, rs9397448, and rs2234693 showed significant genotypic associations with hip fractures, whereas rs3102734, rs2073617, rs1643821, rs12475342, and rs2971886 exhibited significant genotypic and/or haplotypic associations with distal radius fractures. Accordingly, we suggest that in addition to the clinical risk factors, the variants in TNFRSF11B, SPTBN1, ESR1, and LRP4 are susceptibility genetic loci for osteoporotic fracture in postmenopausal Chinese women. © 2012 American Society for Bone and Mineral Research © 2012 American Society for Bone and Mineral Research