bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nitrone cycloaddition to quinones: A novel strategy for the synthesis of benzisoxazolidenes
Authors: Paul Rony Rajan , Varghese Vimal , Beneesh P. B. , Sinu C. R. , Suresh E. , Anabha E. R. 
Published: March 2010

Abstract
magnified image 1,3‐Dipolar cycloaddition reaction involving nitrones and benzoquinones resulting in the formation of benzisoxazolidene is described. As the nitrone is selectively added to carbon–carbon double bond of the benzoquinone, the quinone‐nitrone reaction is considered as a special case among quinone‐1,3‐dipole cycloaddition reactions. Molecular orbital calculation was performed to examine the electronic effects involved in the regioselectivity of the reaction. J. Heterocyclic Chem., (2010).
Efficient synthesis of benzimidazo[1,2‐a]pyrimidinone derivatives via catalyst‐free reactions of Baylis–Hillman acetates, alcohols, and amines with 2‐aminobenzimidazole
Authors: Wang Yan , Shafiq Zahid , Liu Li , Wang Dong , Chen Yong‐Jun 
Published: March 2010

Abstract
magnified image Benzimidazo[1,2‐a]pyrimidinone and its derivatives were easily prepared in good to excellent yields via tandem reactions of 2‐aminobenzimidazole with Baylis–Hillman acetates, alcohols, and amines without the use of catalyst and additive in one‐pot process. The method provided an efficient and facile route to the title fused heterocyclic compounds with different functional groups. J. Heterocyclic Chem., (2010).
Studies in synthesis of new psoralenamines
Authors: Patel Jagdish M. , Soman Shubhangi S. 
Published: March 2010

Abstract
magnified image New amino psoralen derivatives have been synthesized via bromination. Bromination of 3,5‐substituted psoralens has been studied. The second position of the furan ring is more susceptible to bromination than the α‐position of the chromen‐2‐one ring in psoralens. Hence, the target psoralenamines were synthesized starting with 3‐bromo‐7‐hydroxy‐4‐methyl‐chromen‐2‐one, which was condensed with different α‐halo ketones and cyclized in ethanolic potassium hydroxide to get the desired 6‐bromo psoralens, which were finally converted into psoralenamines. J. Heterocyclic Chem., (2010).
One‐pot, three‐component synthesis of spironaphthopyrano[2,3‐d]pyrimidine‐5,3′‐indolines in water
Authors: Ghahremanzadeh Ramin , Amanpour Tayebeh , Sayyafi Maryam , Bazgir Ayoob 
Published: March 2010

Abstract
magnified image A clean, one‐pot and three‐component synthesis of new spironaphthopyrano[2,3‐d]pyrimidine‐5,3′‐indoline derivatives by cyclo‐condensation reaction of isatins, 2‐naphthol, and barbituric acids in aqueous media is reported. J. Heterocyclic Chem., (2010).
A novel camphorsulfonyloxylactonization of alkenoic acids
Authors: Zhu Min , Sun Na‐Bo , Li He , Yan Jie 
Published: March 2010

Abstract
magnified image The novel reaction of [hydroxyl (((+)‐10‐camphorsulfonyl)oxy)iodo]benzene (1) with alkenoic acids was reported. When 1 reacted with various 4‐pentenoic acids in CH3CN, camphorsulfonylactons were obtained in excellent yields in short times, some had two diastereoisomers, whereas 1 reacted with 5‐hexenoic acid, giving middle yield of camphorsulfonylacton; however, 3‐butenoic and trans‐3‐hexenoic acids reacted with 1 slowly in CH2Cl2, only unsaturated lactones were provided. J. Heterocyclic Chem., (2010).
Application of simple clustering on space‐time mapping of mean monthly rainfall pattern
Authors: Nasseri Mohsen , Zahraie Banafsheh 
Published: March 2010

AbstractRain gauges in many watersheds are not enough to represent the spatial and temporal variations of precipitation. Many agricultural activities can be highly sensitive to these variations and therefore different monthly or annual precipitation statistics have been widely used in the literature for agricultural planning and management. For example, mean monthly rainfall has been used as one of the main criteria for classifying suitable regions for dryland farming. In this paper, a method for space‐time estimation of cumulative mean monthly rainfall (CMMR) is presented. The proposed method for estimating CMMR pattern is based on developing time‐varying variogram coupled with ordinary Kriging (OK). OK is selected as a spatial exploration method and all of its parameters are optimised using weighted least square method. K‐means clustering has also been applied to increase the model efficiency. Space‐time estimation of CMMRs in each cluster has been carried out based on the observed CMMRs of the rain gauges in each specific cluster. The proposed method is tested using 25 years of monthly rainfall records of 14 rain gauges in the Maroon watershed in south of Iran. The results of the case study have shown that both methods (estimation with and without clustering) are proper choices for space‐time modelling of rainfall pattern; however, the method in which the rain gauges are classified to different clusters has shown a better statistical performance in terms of normalised mean square error. Copyright © 2010 Royal Meteorological Society
A Raman spectroscopic study on the active site of sodium cations in the structure of Na2Ti3O7 during the adsorption of Sr2+ and Ba2+ cations
Authors: Liu Hongwei , Yang Dongjiang , Waclawik Eric R. , Ke Xuebin , Zheng Zhanfeng , Zhu Huaiyong , Frost Ray L. 
Published: March 2010

AbstractA detailed study on the structural deformation of trititanate nanofibers after the adsorption of divalent strontium (Sr) and barium (Ba) cations was conducted by using Raman spectroscopy, X‐ray diffraction (XRD) and transmission electron microscopy (TEM). It was found that the Raman bands at 309 cm−1 corresponding to very long TiO bonds (2.2 Å) and at 883 cm−1 corresponding to the very short TiO bonds (1.7 Å) decreased in intensity after the adsorption of Ba2+ and Sr2+ cations. Additionally, the band at 922 cm−1 corresponding to an intermediate length TiO bond was observed to weaken with the adsorption of divalent cations, indicating that the TiO6 octahedra in Na2Ti3O7 are more regular. These results suggest that the active sodium (Na+) cations in Na2Ti3O7 should be located at the corner of the TiO6 octahedral slabs, i.e. the plane (003). This was further confirmed by a large decrease of diffraction intensity of the plane (003) observed in the XRD pattern. Copyright © 2010 John Wiley & Sons, Ltd.
Degrees of dysplasia and the use of cidofovir in patients with recurrent respiratory papillomatosis
Authors: Gupta Hina T. , Robinson Robert A. , Murray Ryan C. , Karnell Lucy H. , Smith Richard J. H. , Hoffman Henry T. 
Published: March 2010

AbstractObjectives/Hypothesis:Recurrent respiratory papillomatosis (RRP) is a benign disease characterized by recurrent lesions in the airway. The prevalence and degree of dysplasia that is present in the natural course of RRP is not well established. Adjuvant therapies, such as cidofovir, have been tried with the goal of decreasing the interval between repeat surgical treatments, the mainstay of therapy. Although, the off‐label use of cidofovir to treat RRP has been common, there have been concerns regarding carcinogenic transformation following the use of cidofovir. This study aims to explore the association between increasing degree of papilloma dysplasia and the use of cidofovir in the context of the natural progression of dysplasia in RRP.Study Design:Retrospective case series.Methods:Demographic data and surgical history were obtained through chart reviews for this retrospective case series of 13 patients with RRP who had histopathologic biopsies done before and after exposure to cidofovir. Pathologic data collected over 10 years from serial excisions at the University of Iowa Hospitals were reviewed by a single pathologist, and the highest degree of dysplasia was noted per excision time.Results:Of the 176 specimens collected in these 13 patients with serial papilloma biopsies, 5.7% had no dysplasia, 57.4% had mild dysplasia (grade 1), 28.4% had moderate dysplasia (grade 2), and 8.5% had severe dysplasia (grade 3). A comparison of each patient's multiple biopsies across time suggested that the dysplastic grade was worse in two patients, better in four patients, and virtually unchanged in seven patients. There was no clear‐cut pattern between the use of cidofovir and the degree of dysplasia over time.Conclusions:These results strongly suggest that intralesional cidofovir therapy does not correlate with worsening dysplastic progression. Dysplasia is relatively common in the setting of RRP; however, the prognostic significance of this finding is unknown. Additional research is needed to delineate the natural progression of dysplasia and its clinical significance in RRP, as well as the efficacy of cidofovir. Laryngoscope, 2010
What makes a good flap go bad?: A critical analysis of the literature of intraoperative factors related to free flap failure
Authors: Pattani Kavita M. , Byrne Patrick , Boahene Kofi , Richmon Jeremy 
Published: March 2010

AbstractObjectives/Hypothesis:The purpose of this article is to discuss the various factors related to poor outcome in free flap reconstructions of the head and neck (H&N). Free tissue transfer has become the standard reconstruction technique for complex H&N defects. With the evolution of free flap use in H&N surgery, numerous factors have been proposed that adversely affect flap outcome, many with the support of only anecdotal experience. We seek to critically review the literature to assess what evidence exists for the relation of various intraoperative factors to free flap complications.Study Design:Literature review.Methods:A review of the contemporary literature (1995 to present) on free flap reconstruction of the H&N was undertaken. A PubMed search using the terms head and neck, reconstruction, free flap, microvascular, failure, complications, fluids, intraoperative, hypertension, hypotension, nitrous oxide, temperature, and morbidity in various combinations was completed. Appropriate articles were selected and analyzed.Results:Studies report various factors thought to influence flap outcomes, often with divergent conclusions. Nonetheless, the body of evidence implicates several intraoperative factors to contribute to free flap complications including: >7 L intraoperative fluid administration, significant medical comorbidity, and prolonged operative time. There is no evidence supporting hypotension, pressors, colloids, and nitrous use in free flap failure.Conclusions:Although various dogmas related to the intraoperative care of free flap patients exist, including avoidance of hypotension and pressor use, there is no available clinical evidence to support these practices. Although free flap failure is uncommon, a better understanding of its causes is necessary to avoid this disastrous complication. Laryngoscope, 2010
Adjustable laterofixation of the vocal fold in bilateral vocal fold paralysis
Authors: Ezzat Waleed F. , Shehata Mohammed , Kamal Ihab , Riad Magdy Amin 
Published: March 2010

AbstractObjectives/Hypothesis:To describe a modification of VF laterofixation in patients with bilateral vocal fold paralysis (VFP), which allows adjusting the sutures tension according to voice and airway patency in the first postoperative day.Study Design:Prospective case study.Methods:Twenty‐one patients with recent bilateral VFP were treated by the modified laterofixation technique in Ain‐Shams University hospitals between May 2007 and February 2009. Eight male patients and 13 females were included. The median age of the group was 36 years. The standard laterofixation procedure was performed; the Prolene sutures were inserted through the thyroid ala cartilage and looped around the paralyzed VF just anterior to the vocal process. The ultimate tension of the suture was adjusted later in the first postoperative day to gain feedback from the conscious patient about the airway patency and voice quality.Results:Satisfactory immediate result was achieved in 16 patients, with adequate airway, voice, and swallowing. Three other patients required bilateral procedures, one patient needed revision surgery. The procedure failed to achieve a satisfactory airway in one patient who remained dependant on a tracheotomy.Conclusions:The modified laterofixation technique is a reliable first line treatment for recent bilateral VFP. Laryngoscope, 2010
Clinical behavior of follicular variant of papillary thyroid carcinoma: Presentation and survival
Authors: Lin Harrison W. , Bhattacharyya Neil 
Published: March 2010

AbstractObjectives/Hypothesis:To determine the prevalence and extent of disease characteristics of the follicular variant of papillary thyroid carcinoma (FV‐PTC) and the survival impact of this histopathological diagnosis compared to classical papillary thyroid carcinoma (C‐PTC).Study Design:Cross‐sectional population analysis of a national cancer database.Methods:Cases of C‐PTC and FV‐PTC were extracted from the Surveillance, Epidemiology and End Results database for 1988 to 2006 and staged. Surgical extent and radioactive iodine (RAI) use were determined. Demographic and staging parameters were statistically compared according to tumor histology. Survival differences according to histology were determined with a Cox proportional hazards model, adjusting for age, sex, T stage, N stage, surgical therapy, and RAI.Results:A total of 46,699 patients were identified (68.4% C‐PTC and 31.6% FV‐PTC). Age at presentation and sex distribution were similar between FV‐PTC (47.9 years; 79.3% female) and C‐PTC patients (46.2 years; 77.3% female). Although nodal disease prevalence was significantly lower in FV‐PTC compared to C‐PTC (14.8% vs. 27.8%, respectively; P < .001), T stage was not significantly different (P = .450). Mean overall survivals for patients with FV‐PTC (204.5 months) and C‐PTC (205.3 months) were not significantly different (P = .373). Cox regression analysis revealed that advanced age (P < .001), male sex (P < .001), advanced T stage (P < .001), and positive nodal disease (P < .001) were associated with reduced overall survival, whereas histopathological subtype was not (P = .360).Conclusions:Disease presentation (with exception of nodal metastasis) and survival in patients with FV‐PTC are statistically similar to that of C‐PTC, and accordingly these patients carry very similar prognoses. Laryngoscope, 2010
Correction of chloride threshold concentration and time‐to‐corrosion due to reinforcement presence
Authors: Yu H. , Hartt W. H. 
Published: March 2010

AbstractReinforcement presence affecting corrosion threshold concentration, Ct, determination and time‐to‐corrosion, Ti, has been investigated. Elevated Ct and decreased Ti due to reinforcement physical obstruction on the path of chloride ingression into concrete has been examined with finite element modeling. Results indicated that reinforcement with larger size, better corrosion resistance, less cover thickness, or a more flat leading edge causes more pronounced Ti reduction. Experimental results exposed aggregate content discrepancy within reinforced bar vicinity zone. According to this finding, a multi‐shell chloride diffusion model, in which specific chloride ion diffusivity in each shell surrounding bar presents, is proposed. The Ct results of proposed model are discussed along with those acquired from traditional one‐dimensional model, in which chloride diffusion follows Fick's second law without considering reinforcement presence, and two‐dimensional model with the effect of reinforcement physical obstruction regarded.
A New Polymeric pH Sensor Based on Photophysical Property of Gold Nanoparticle and pH Sensitivity of Poly(sulfadimethoxine methacrylate)
Authors: Hong Seok Hwan , Hong Sung Woo , Jo Won Ho 
Published: March 2010

AbstractA new pH sensor, which consists of a fluorophore and gold nanoparticle (AuNP) attached to each chain end of a pH‐sensitive polysulfonamide, respectively, is synthesized, and its pH sensitivity is investigated in terms of the fluorescent quenching efficiency of AuNP. Since the pH‐sensitive polymeric linker exhibits a pH‐induced coil–globule transition that is rapid enough to show a typical two‐state transition, it shows drastic on‐and‐off quenching efficiency with variation of pH due to the change in the distance between fluorophore and AuNP. This AuNP‐based pH sensor exhibits a well‐defined on‐and‐off behavior at a small change in pH, and therefore can be used for an ideal alarm‐type sensor.magnified image
Preparation of Polyethylene/Montmorillonite Nanocomposites Through in situ Polymerization Using a Montmorillonite‐Supported Nickel Diimine Catalyst
Authors: Choi Yiyoung , Shin Sang Young A. , Soares João B. P. 
Published: March 2010

AbstractPE/MMT nanocomposites were prepared through in situ polymerization using a nickel diimine catalyst supported on commercially available MMTs such as Cloisite Na+, Cloisite 30B, and Cloisite 93A. XRD patterns revealed that the layers of Cloisite 30B and Cloisite 93A were intercalated after treatment with TMA and the nickel diimine complex. The catalyst supported on Cloisite 30B showed high yields without additional activator and produced nanocomposites with high melting and decomposition temperatures. The thermal properties and crystallinity could be controlled by varying the clay content in the nanocomposite. The morphologies of the resulting particles and the dispersion of the MMT layers in the polymer matrix were characterized by SEM and TEM.magnified image
(Co‐)Polyesters Derived from Isosorbide and 1,4‐Cyclohexane Dicarboxylic Acid and Succinic Acid
Authors: Garaleh Mazen , Yashiro Takao , Kricheldorf Hans R. , Simon Peter , Chatti Saber 
Published: March 2010

AbstractThe homopolyester of isosorbide and cis–trans 1,4‐cyclohexane dicarboxylic acid (CHDA) was prepared by three different methods, but only polycondensation of isosorbide and CHDA dichloride yielded a satisfactory molecular weight (corrected $\overline M _{\rm n} $ = 11 000 Da). For the best sample the MALDI‐TOF mass spectrum revealed a high content of cycles. The homopolyester of CHDA and isomannide or isoidide was prepared analogously. For the homopolyesters of CHDA high glass transition temperatures were found (Tg = 146 °C for isosorbide, 133 °C for isomannide, and 115 °C for isoidide), whereas the polyester of isosorbide and succinic acid (SuA) has a Tg around 77 °C. Copolyester of isosorbide and various molar ratios of CHDA and SuA were prepared by two different methods, but only rather low molecular weights were obtained. SEC measurements with and without “universal calibration” revealed that the normal calibration with polystyrene overestimates the real molecular weights by 30–45%.magnified image
Monodisperse Polystyrene Nanospheres with Ultrahigh Surface Area: Application for Hydrogen Storage
Authors: Liu Qingquan 
Published: March 2010

AbstractMonodisperse hyper‐crosslinked polystyrene nanospheres with ultrahigh specific surface area were successfully prepared by emulsifier‐free miniemulsion polymerization and post‐crosslinking. The specific surface area and the total pore volume of hyper‐crosslinked nanospheres were increased with increasing the concentration of vinybenzyl chloride in monomer mixture. The hyper‐crosslinked nanospheres exhibited excellent swelling capacity in thermodynamically good and poor solvent. Furthermore, the nanospheres with specific surface area of 1 223 m2 · g−1 adsorbed 2.13 wt.‐% hydrogen at 163 K/1.5 MPa. Overall, the present study provided a simple method to prepare monodisperse microporous hyper‐crosslinked polymer nanospheres.magnified image
Rheology and Physical Characteristics of Synthetic Biodegradable Aliphatic Polymer Blends Dispersed with MWNTs
Authors: Ko Seung Woo , Gupta Rahul K. , Bhattacharya Sati N. , Choi Hyoung Jin 
Published: March 2010

AbstractPLA/PBAT blends and PLA/PBAT/MWNT nanocomposite systems were prepared via a melt mixing process to examine their thermal and rheological properties. To compare the polymer blend/MWNT nanocomposite with a pure polymer/MWNT nanocomposite, PLA/MWNT, PBAT/MWNT, and PLA/PBAT/MWNT nanocomposite systems were prepared. TEM and SEM were used to observe that one phase has better affinity with the MWNT, while the MWNT was found to increase both the thermal properties of the PLA/PBAT blends and rheological properties of the PLA/PBAT/MWNT nanocomposite with distinct shear‐thinning behavior due to the addition of the MWNT. An increase in the storage (G′) and loss (G″) moduli for the PLA/PBT/MWNT nanocomposite was also observed.magnified image
Monte Carlo Simulations of Metallo‐Supramolecular Micelles
Authors: Wang Shihu , Dormidontova Elena E. 
Published: March 2010

AbstractUsing Monte Carlo simulations we show that the equilibrium properties of metallo‐supramolecular micelles are determined by the competition of 2:1 and 1:1 metal–ligand complexation in the bulk and on the surface as well as steric interactions between the neighboring corona blocks attached to the surface. We predict that by increasing the association energy for the second metal–ligand bond, or decreasing the corona block length one can achieve a larger core surface coverage for metallo‐supramolecular micelles. Compared to covalently bonded block copolymer micelles, we show that metallo‐supramolecular micelles have smaller monomer and end group density, especially in the vicinity of the core, which may lead to experimentally observed aggregation.magnified image
Vitamin E supplementation and mammalian lifespan
Authors: Banks Ruth , Speakman John R. , Selman Colin 
Published: March 2010

AbstractVitamin E refers to a family of several compounds that possess a similar chemical structure comprising a chromanol ring with a 16‐carbon side chain. The degree of saturation of the side chain, and positions and nature of methyl groups designate the compounds as tocopherols or tocotrienols. Vitamin E compounds have antioxidant properties due to a hydroxyl group on the chromanol ring. Recently, it has been suggested that vitamin E may also regulate signal transduction and gene expression. We previously reported that lifelong dietary vitamin E (α‐tocopherol) supplementation significantly increased median lifespan in C57BL/6 mice by 15%. This lifespan extension appeared to be independent of any antioxidant effect. Employing a transcriptional approach, we suggest that this increase in lifespan may reflect an anti‐cancer effect via induction of the P21 signalling pathway, since cancer is the major cause of death in small rodents. We suggest that the role of this pathway in life span extension following supplementation of vitamin E now requires further investigation.
Structure and stereochemistry of novel ecdysteroids from the roots of Serratula wolffii
Authors: Takács Mária , Simon András , Liktor‐Busa Erika , Báthori Mária , Zsila Ferenc , Bikádi Zsolt , Horváth Péter , Veress Gábor , Gergely András , Tóth Gábor 
Published: March 2010

AbstractThree new natural ecdysteroids viz. 22‐dehydro‐20‐deoxy‐ajugasterone C (1), 1‐hydroxy‐22‐deoxy‐20,21‐didehydro‐ecdysone (2) and 22‐deoxy‐20,21‐didehydro‐ecdysone (3) were isolated from the methanol extract of the roots of Serratula wolffii. The structures of compounds 1–3 were established by various spectroscopic techniques, including one‐ and two‐dimensional NMR, circular dichroism and mass spectroscopic methods. Copyright © 2010 John Wiley & Sons, Ltd.
Beyond taxonomy
Authors: Helm Scott T. , Andersson Fredrik O. 
Published: March 2010

AbstractMuch of the considerable confusion about the definition of social entrepreneurship in academic literature stems from a lack of empirical research on the subject. This article advances social entrepreneurship research beyond conceptualization discussions by developing and validating an instrument that quantifies the incidence of nonprofit entrepreneurial behavior. Information from 145 Kansas City Metropolitan Area nonprofit organizations was collected to validate the underlying constructs represented in the instrument. Behavior differences were depicted between entrepreneurial and nonentrepreneurial nonprofits. Using principal component factor analysis, the research illustrates social entrepreneurship as a unique nonprofit behavior that occurs at the intersection of innovation, proactiveness, and risk taking.