bluuebunny/crossref_metadata_2025_split huggingface dataset:
Glycerol catalytic cyclocondensation with ethanediamine to pyrazinyl compounds over the modified SiO2‐Al2O3
Authors: Liu Chuanqi , Xu Chenghua , Xia Tongwei , Guo Yan , Liu Jianying 
Published: May 2012

AbstractThe Fe, Zn, and Mn‐modified SiO2‐Al2O3 catalysts for the glycerol vapor‐phase cyclocondensation with ethanediamine (ED) to 2‐pyrazinemethanol (2‐PMol) and 2‐methylpyrazine (2‐MP) in a fixed‐bed system were prepared by coprecipitation and characterized by N2 adsorption–desorption, X‐ray powder diffraction, and NH3 temperature‐programmed desorption (NH3‐TPD) in the present work. The results showed that the Mn‐modified SiO2‐Al2O3 catalyst with a SiO2/Al2O3 molar ratio 15.84 and 6% Mn gave the highest catalytic activity for formation of 2‐PMol (53.1%) and 2‐MP (42.9%). Mn species could cause the modulation of the acidic species of catalysts, improving the glycerol cyclocondensation with ED to 2‐PMol, and also acted as the catalytic centers for the hydrodehydration of 2‐PMol to 2‐MP. However, too many strong acidic sites could lead to ED self‐cyclocondensation to form a by‐product pyrazine. The optimum temperature was tested to be 380°C for the cyclocondensation over a 6%Mn‐SiO2‐Al2O3 catalyst. © 2012 Wiley Periodicals, Inc. Heteroatom Chem 23:377–382, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.21026
A Novel Asymmetric Synthesis of 3‐(1H‐Pyrrol‐1‐yl)‐Substituted β‐Lactams via a Bismuth Nitrate‐Catalyzed Reaction
Authors: Shaikh Aarif L. , Banik Bimal K. 
Published: May 2012

AbstractThe reaction of racemic α‐keto β‐lactams 5a–5c with the commercially available chiral compound trans‐4‐hydroxy‐L‐proline (6) in the presence of a catalytic amount of Bi(NO3)3⋅5 H2O in EtOH gave a diastereoisomer mixture of β‐lactams with a pyrrole ring at C(3) (7 to 12). This is the first enantioselective synthesis of optically active β‐lactams (=azetidin‐2‐ones) that possess a pyrrolyl residue at C(3), in a single step.
Radical Cyclization Reactions via Manganese(III) Acetate Leading to 2‐Thienyl‐Substituted Dihydrofuran Compounds
Authors: Biçer Emre , Yılmaz Mehmet , Karataş Melih , Pekel Ahmet Tarık 
Published: May 2012

AbstractThe 2‐thienyl‐substituted 4,5‐dihydrofuran derivatives 3–8 were obtained by the radical cyclization reaction of 1,3‐dicarbonyl compounds 1a–1f with 2‐thienyl‐substituted conjugated alkenes 2a–2e by using [Mn(OAc)3] (Tables 1–5). In this study, reactions of 1,3‐dicarbonyl compounds 1a–1e with alkenes 2a–2c gave 4,5‐dihydrofuran derivatives 3–5 in high yields (Tables 1–3). Also the cyclic alkenes 2d and 2e gave the dihydrobenzofuran compounds, i.e., 6 and 7 in good yields (Table 4). Interestingly, the reaction of benzoylacetone (=1‐phenylbutane‐1,3‐dione; 1f) with some alkenes gave two products due to generation of two stable carbocation intermediates (Table 5).
Synthesis of a Novel C2‐Symmetric Bis‐oxazoline (=Bis[4,5‐dihydrooxazole]) and Its Application as Chiral Ligand in Asymmetric Transition Metal Catalysis
Authors: Gök Yaşar , Van der Eycken Johan 
Published: May 2012

AbstractThe new C2‐symmetric bis‐oxazoline (=bis[4,5‐dihydrooxazole]) 2 with a chiral trans‐(2R,3R)‐2,3‐bis(3,5‐diphenylphenyl)cyclopropylidene (=trans‐(2R,3R)‐2,3‐bis([1,1′: 3′,1″‐terphenyl]‐5′‐yl)cyclopropylidene) backbone was efficiently synthesized (Scheme). All synthetic steps were easy to perform and led to the desired product in good overall yields. Compound 2 was tested and compared as ligand in several enantioselective catalytic reactions such as palladium(0)‐catalyzed enantioselective allylic alkylations and copper(I)‐catalyzed enantioselective cyclopropanations and aziridinations.
Femtosecond laser microstructuring for polymeric lab‐on‐chips
Authors: Eaton Shane M. , De Marco Carmela , Martinez‐Vazquez Rebeca , Ramponi Roberta , Turri Stefano , Cerullo Giulio , Osellame Roberto 
Published: May 2012

AbstractThis paper provides an overview of femtosecond laser microfabrication in polymeric materials, with emphasis on lab‐on‐chip applications. Due to the nonlinear interaction of femtosecond laser pulses with polymers, laser‐induced modifications are localized to the focal volume, enabling high resolution patterning in 3D. Femtosecond laser microfabrication offers unmatched versatility in fabricating surface microchannels and diffractive optics by means of laser ablation, buried optical waveguides and micro‐optics through refractive index modification and complex 3D microstructures in photoresists by two‐photon polymerization. Femtosecond laser microfabrication technology opens the door to fabricating integrated lab‐on‐chip devices with a single tool. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Tailoring the spectral response of liquid waveguide diagnostic platforms
Authors: Zhao Yue , Phillips Brian , Ozcelik Damla , Parks Joshua , Measor Philip , Gulbransen David , Schmidt Holger , Hawkins Aaron R. 
Published: May 2012

AbstractLiquid filled waveguides that form the basis for on‐chip biophotonics diagnostic platforms have primarily found application in fluorescence and Raman spectroscopy experiments that require sensitive discrimination between weak analyte signals and a variety of background signals. Primary sources of background signal can include light from excitation sources (strong, narrow frequency band) and photoluminescence generated in waveguide cladding layers (weak, wide frequency band). Here we review both solid and liquid core filtering structures which are based on anti‐resonant reflection that can be integrated with waveguides for attenuating undesirable optical bands. Important criteria to consider for an optimized biosensor include cladding layer materials that minimize broad‐spectrum photoluminescence and optimize layer thicknesses for creating a desired spectral response in both solid and liquid guiding layers, and a microfabrication process capable of producing regions with variable spectral response. New results describing how spurious fluorescence can be minimized by optimized thermal growth conditions and how liquid‐core filter discrimination can be tuned with liquid core waveguide length are presented. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
11α hydroxylation of 16α, 17‐epoxyprogesterone in biphasic ionic liquid/water system by Aspergillus ochraceus
Authors: Mao Shuhong , Hua Boyuan , Wang Na , HU Xiaojie , Ge Zhijiang , Li Yanqing , Liu Sha , Lu Fuping 
Published: May 2012

AbstractBACKGROUND: The improved efficiency of steroid biotransformation using the biphasic system is generally attributed to the positive effect on the solubility of substrate in aqueous media. A promising alternative for the application of organic solvents in biphasic systems is the use of ionic liquids (ILs). This study aims to investigate the applicability of the biphasic ILs/water system for 11α hydroxylation of 16α, 17‐epoxyprogesterone (HEP) by Aspergillus ochraceus.RESULTS: Of the seven ILs tested, [C3mim][PF6] exhibited the best biocompatibility, with markedly improved biotransformation efficiency. In the [C3mim][PF6]‐based biphasic system, substrate conversion reached 90% under the condition in which buffer pH, volume ratio of buffer to ILs, cell concentration, and substrate concentration were 4.8, 10/1, 165 g L−1 and 20 g L−1, respectively. This is more efficient than that of the monophasic aqueous system. The effects of the cations and anions of these ILs on the 11α hydroxylation of 16α, 17‐epoxyprogesterone (HEP) by A. ochraceus is also discussed.CONCLUSION: The above results showed that IL/water biphasic system improved the efficiency of 11α hydroxylation of 16α, 17‐epoxyprogesterone (HEP) by A. ochraceus, thus suggesting the potential industrial application of ILs‐based biphasic systems for steroid biotransformation. © 2012 Society of Chemical Industry
Pilot‐scale anaerobic/anoxic/oxic/oxic biofilm process treating coking wastewater
Authors: Zhou Xin , Li Yaxin , Zhao Yi , Yue Xiuping 
Published: May 2012

AbstractBACKGROUND: Biological treatment efficiency of coking wastewater is rather poor, especially for chemical oxygen demand (COD) and ammonia‐nitrogen (NH$_{4}^{+}$‐N) removal due to its complex composition and high toxicity.RESULTS: A pilot‐scale anaerobic/anoxic/oxic/oxic (A2/O2) biofilm system has been developed to treat coking wastewater, focusing attention on the COD and NH$_{4}^{+}$‐N removal efficiencies. Operational results over 239 days showed that hydraulic retention time (HRT) of the system had a great impact on simultaneous removals of COD and NH$_{4}^{+}$‐N. At HRT of 116 h, total removal efficiencies of COD and NH$_{4}^{+}$‐N were 92.3% and 97.8%, respectively, reaching the First Grade discharge standard for coking wastewater in China. Adequate HRT, anoxic removal of refractory organics and two‐step aerobic bioreactors were considered to be effective measures to obtain satisfactory coking effluent quality using the A2/O2 biofilm system. The correlation between removal characteristics of pollutants and spatial distributions of biomass along the height of upflow bioreactors was also revealed.CONCLUSION: The study suggests that it is feasible to apply the A2/O2 biofilm process for coking wastewater treatment, achieving desirable effluent quality and steady process performance. © 2012 Society of Chemical Industry
Famotidine suppresses osteogenic differentiation of tendon cells in vitro and pathological calcification of tendon in vivo
Authors: Yamamoto Kenichi , Hojo Hironori , Koshima Isao , Chung Ung‐il , Ohba Shinsuke 
Published: May 2012

AbstractHeterotopic ossification or calcification follows any type of musculoskeletal trauma and is known to occur after arthroplasties of hip, knee, shoulder, or elbow; fractures; joint dislocations; or tendon ruptures. Histamine receptor H2 (Hrh2) has been shown to be effective for reducing pain and decreasing calcification in patients with calcifying tendinitis, which suggested that H2 blockers were effective for the treatment of tendon ossification or calcification. However, the detailed mechanisms of its action on tendon remain to be clarified. We investigated the mechanisms underlying H2 blocker‐mediated suppression of tendon calcification, with a focus on the direct action of the drug on tendon cells. Famotidine treatment suppressed the mRNA expressions of Col10a1 and osteocalcin, ossification markers, in a tendon‐derived cell line TT‐D6, as well as a preosteoblastic one MC3T3‐E1. Both of the cell lines expressed Hrh2; histamine treatment induced osteocalcin expression in these cells. Famotidine administration suppressed calcification in the Achilles tendon of ttw mice, a mouse model of ectopic ossification. These data suggest that famotidine inhibits osteogenic differentiation of tendon cells in vitro, and this inhibition may underlie the anti‐calcification effects of the drug in vivo. This study points to the use of H2 blockers as a promising strategy for treating heterotopic ossification or calcification in tendon, and provides evidence in support of the clinical use of famotidine. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:1958–1962, 2012
Evaluation of Citrus aurantifolia peel and leaves extracts for their chemical composition, antioxidant and anti‐cholinesterase activities
Authors: Loizzo Monica Rosa , Tundis Rosa , Bonesi Marco , Menichini Federica , De Luca Damiano , Colica Carmela , Menichini Francesco 
Published: May 2012

AbstractBACKGROUND: The replacement of synthetic antioxidants by safe natural antioxidants fosters research on the screening of vegetables and food as sources of new antioxidants. Moreover, oxidative degeneration of cells is associated with neurodegenerative diseases such as Alzheimer's disease. On the basis of these considerations this work aimed to investigate the antioxidant properties [by using the diphenyl picryl hydrazyl, 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) and ferric reducing ability of plasma assays, and the β‐carotene bleaching test] and the anti‐cholinesterase activity of Citrus aurantifolia peel and leaves from different areas of growth.RESULTS: Methanol extracts of the peel and leaves demonstrated the strongest radical scavenging activity. A similar trend was observed with the reducing ability, with values from 112.1 to 146.0 µmol L−1 Fe(II) g−1. The relationship between phenol and flavonoid contents and antioxidant activity was statistically investigated. Based on analysis by high‐performance liquid chromatography, the most abundant flavonoids found in C. aurantifolia extracts were apigenin, rutin, quercetin, kaempferol and nobiletin. n‐Hexane fractions of both peel and leaves showed a good acetylcholinesterase inhibitory activity with IC50 values in the range 91.4‐107.4 µg mL−1. Gas chromatography‐mass spectrometry analysis revealed the presence of monoterpenes and sesquiterpenes as most common components.CONCLUSION: The findings of this study suggest a potential use of C. aurantifolia peel and leaves for supplements for human health. Copyright © 2012 Society of Chemical Industry
The incidence of metastasis from cutaneous squamous cell carcinoma and the impact of its risk factors
Authors: Brougham Nicholas D.L.S. , Dennett Elizabeth R. , Cameron Rujuta , Tan Swee T. 
Published: May 2012

AbstractBackgroundCutaneous squamous cell carcinoma (cSCC), the most common cancer capable of metastasis, has variable reported metastatic rates and the impact of individual risk factors for metastasis is unknown.MethodsThis study examined pathology records of excised cSCC over a 10‐year period. Uni‐variate and multi‐variate analyses including patient demographics, maximum clinical diameter (MCD), anatomical sub‐site, histological differentiation, perineural invasion (PNI), and lymphovascular invasion (LVI) of the lesion were performed. The primary endpoint was time to metastasis.ResultsSix thousand one hundred sixty four patients (median age 74 years) underwent excision of 8,997 primary cSCC. During the median follow‐up of 70 months, the metastatic rate of cSCC was 1.9–2.6%. Multi‐variate analysis showed that MCD (hazards ratio 1.41 [95% CI 1.25–1.60] P < 0.001), PNI (5.29; P < 0.0001), poor histological differentiation (4.26; P < 0.0001), location in the ear and retro‐auricular area (3.31 [1.17–9.33]; P = 0.0024), cheek (3.18 [1.15–8.81]; P = 0.026), and lip (4.84; P = 0.009) increased the risk of metastasis.ConclusionsWe show a 1.9–2.6% metastatic rate for cSCC with MCD, histologic differentiation, PNI, and certain anatomical sub‐sites being independent risk factors for metastasis. A prospective study on our proposed risk stratification scheme based on these parameters may lead to identification of high‐risk lesions that would benefit from more intensive treatment and/or routine post‐operative follow‐up. J. Surg. Oncol. 2012; 106:811–815. © 2012 Wiley Periodicals, Inc.
A methodology to investigate the wear of blast furnace hearth carbon refractory lining
Authors: Silva S. N. , Vernilli F. , Justus S. M. , Longo E. , Baldo J. B. , Varela J. A. , Lopes J. M. G. 
Published: May 2012

AbstractIn this work it is presented a methodology applied by Companhia Siderúrgica Nacional (CSN, Brazil) in order to assess its blast furnace 3 carbon refractory hearth lining conditions. The aim of the investigation was the gathering of critical data base for blast furnace refractories life cycle follow up and eventual repair decision taking.The sample drilling locations were chosen around the tap holes and hearth bottom areas. The advancing drilling depths were based on local temperature profiles. The isotherm limit of 500 °C was elected as a control parameter to assess the critical carbon refractory condition. The guidelines for sampling and testing as well as the results obtained through the physical and chemical characterizations of the cored samples are presented. The condition of the refractory lining is discussed under the light of the different known wear mechanisms of blast furnace hearth carbon refractories.
Antipodal linearly tapered slot antenna using unequal half‐circular defected sides for gain improvements
Authors: In Dae‐Myoung , Lee Min‐Jae , Kim Donghyun , Oh Chang‐Yul , Kim Young‐Sik 
Published: May 2012

AbstractIn this Letter, a new antipodal linearly tapered slot antenna (ALTSA) with unequal half‐circular slots (UHCS) embedded on both edge‐sides is proposed to improve an antenna gain. The proposed antenna operates over the frequency band from 3.1 GHz to more than 10.6 GHz, which is assigned to Ultra‐Wideband wireless communications. The proposed antenna has been improved in a gain and reduced to backward radiation due to the unequal half‐circular slots on the ALTSA. The measured antenna gains are improved by up to 3.5 dB. The side lobe levels are lowered by about −14.8 and −7.2 dB in the E‐ and H‐planes at 7 GHz, respectively. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1963–1965, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26942
Simplified approach to low‐cost multiparameter monitoring based on low frequency polarization modulation
Authors: Floridia C. , Simões G.C. C. P. , Bezerra E. W. , Feres M. M. , Romero M. A. 
Published: May 2012

AbstractWe experimentally revisit a technique of low‐cost multiparameter monitor for optical performance monitoring based on low frequency polarization modulation. A simplified calibration procedure, which significantly reduces the mathematical complexity and processing effort is proposed. Validation is achieved by carrying out relative optical power, wavelength, and differential group delay measurements. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1820–1824, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26956
Compact monopole antenna design for WLAN/WiMAX triple‐band operations
Authors: Yoon Joong Han , Rhee Young Chul , Jang Yeon Kil 
Published: May 2012

AbstractA novel design of a simple microstrip‐fed monopole antenna well suited to wireless local area network (WLAN)/worldwide interoperability for microwave access (WiMAX) application for triple‐band operation is proposed in this article. The proposed antenna consists of one branch strip, two hook‐shaped strips, an asymmetrical ground plane, and a rectangular slit in the ground plane. Through the proper selection of the dimensions as well as arrangement of the strips, desired resonant modes excited at 2.35/3.65/5.375 GHz with a less than −10‐dB input impedance frequency response can be achieved. Prototypes of the proposed antenna were fabricated and experimentally measured, and an acceptable agreement between the measurement and simulation results was achieved. The numerical and experimental results demonstrate that the proposed antenna satisfies the −10‐dB impedance bandwidth requirement while covering the WLAN and WiMAX bands simultaneously. Meanwhile, the 2D radiation patterns and 3D gain performance of the antenna in the operation bands were also observed and discussed. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1838–1846, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26963
A fully integrated rf front end for DVB‐SH
Authors: García‐Vázquez Hugo , Khemchandani Sunil L. , Ramos‐Valido Dailos , Juanicorena Aitor , Luján‐Martínez Carmen , del Pino Javier 
Published: May 2012

AbstractThis article describes a RF front end for DVB‐SH (2.17–2.2 GHz) implemented in UMC CMOS 90 nm process. This receiver includes a low noise amplifier (LNA), a single‐to‐differential converter, and a mixer. The LNA is based on cascode topology combined with a narrow band impedance matching and LC tank load. The single‐to‐differential converter generates a pair of differential output signals from a single input, which have balanced amplitude and phase. This converter is followed by a Gilbert cell based quadrature mixer. The measurements show a conversion gain of 15.7–15.5 dB, an input return loss (S11) of −12 dB, and an output compression point of 1.92 dBm. This receiver has a simulated noise figure of 2.2 dB. This combination draws 22 mW from a 1.2‐V supply. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1944–1949, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26974
Proximity study of a conformal UWB directional antenna on water pipe
Authors: Gaetano Domenico , Ammann Max J. , McEvoy Patrick , John Matthias , Keating Louise , Horgan Frances 
Published: May 2012

AbstractA preliminary study on the conformal properties of an antipodal exponentially tapered antenna placed on the surface of a flow meter system in the UWB range is presented. It was observed that the water effect can be mitigated by shifting the antenna away from the pipe surface. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1982–1986, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26979
High‐resolution human diffusion tensor imaging using 2‐D navigated multishot SENSE EPI at 7 T
Authors: Jeong Ha‐Kyu , Gore John C. , Anderson Adam W. 
Published: May 2012

AbstractThe combination of parallel imaging with partial Fourier acquisition has greatly improved the performance of diffusion‐weighted single‐shot EPI and is the preferred method for acquisitions at low to medium magnetic field strength such as 1.5 or 3 T. Increased off‐resonance effects and reduced transverse relaxation times at 7 T, however, generate more significant artifacts than at lower magnetic field strength and limit data acquisition. Additional acceleration of k‐space traversal using a multishot approach, which acquires a subset of k‐space data after each excitation, reduces these artifacts relative to conventional single‐shot acquisitions. However, corrections for motion‐induced phase errors are not straightforward in accelerated, diffusion‐weighted multishot EPI because of phase aliasing. In this study, we introduce a simple acquisition and corresponding reconstruction method for diffusion‐weighted multishot EPI with parallel imaging suitable for use at high field. The reconstruction uses a simple modification of the standard sensitivity‐encoding (SENSE) algorithm to account for shot‐to‐shot phase errors; the method is called image reconstruction using image‐space sampling function (IRIS). Using this approach, reconstruction from highly aliased in vivo image data using 2‐D navigator phase information is demonstrated for human diffusion‐weighted imaging studies at 7 T. The final reconstructed images show submillimeter in‐plane resolution with no ghosts and much reduced blurring and off‐resonance artifacts. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.
A staggered nonlocal multiscale model for a heterogeneous medium
Authors: Fish Jacob , Jiang Tao , Yuan Zheng 
Published: May 2012

SUMMARYA staggered nonlocal multiscale model for a heterogeneous medium is developed and validated. The model is termed as staggered nonlocal in the sense that it employs current information for the point under consideration and past information from its local neighborhood. For heterogeneous materials, the concept of phase nonlocality is introduced by which nonlocal phase eigenstrains are computed using different nonlocal phase kernels. The staggered nonlocal multiscale model has been found to be insensitive to finite element mesh size and load increment size. Furthermore, the computational overhead in dealing with nonlocal information is mitigated by superior convergence of the Newton method. Copyright © 2012 John Wiley & Sons, Ltd.