bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinetics of the reaction of arylethanediylidene‐bis‐dithiocarbazonoate Ni complexes with morpholine in benzene: Substituent and temperature effects
Authors: Shehata Aziza K. , Fathalla Magda F. , Header Heba M. A. , Hamed Ezzat A. 
Published: September 2011

Abstract[1‐Arylethanediylidene‐bis(methyl dithiocarbazonoate) NN′SS′ (−2)]Ni(II) complexes were prepared by condensation of arylglyoxals with methyl dithiocarbazoate to give the corresponding hydrazonoates. The chelation of nickel(II) with these hydrazonoates gave square planar Ni complexes. The k3 values for the substitution of SCH3 close to the aryl group with morpholine (Mo) in benzene were found to increase steadily (20–35°C) followed by a sudden drop after 35°C. A continuous decrease in k3 values was observed by further elevation in the temperature. The Arrhenius plot showed a convex curve at the whole temperatures 20–55°C, and negative ΔH# values for the reactions were obtained at 40–55°C. The Hammett plots at the temperature ranges 20–35° and 40–55°C exhibited good straight lines with ρ values of 1.44–0.73 and 1.18–1.25, respectively. The proposed mechanism is a nucleophilic aromatic substitution‐like, in which the rate‐determining step is the proton transfer process in the temperature range 20–35°C whereas the mechanism in the range 40–55°C passes through the attack of Mo on the carbon carrying the SCH3 group followed by the addition of the second Mo molecule on Ni to form an intermediate, which undergoes elimination of Mo and CH3SH to give a monosubstitution complex. © 2011 Wiley Periodicals, Inc. Int J Chem Kinet 44: 27–40, 2012
Swallowing function after transoral laser microsurgery (TLM) ± adjuvant therapy for advanced‐stage oropharyngeal cancer
Authors: Rich Jason T. , Liu Jingxia , Haughey Bruce H. 
Published: September 2011

AbstractObjectives/Hypothesis:To perform a longitudinal description of swallowing function following transoral laser microsurgery (TLM) ± adjuvant therapy for advanced‐stage oropharyngeal cancer (OPC) and identify prognostic factors associated with swallowing performance.Study Design:Retrospective analysis and longitudinal descriptive study of swallowing outcomes.Methods:Patients treated with TLM for AJCC stage III–IV OPC at Washington University from 1996 to 2008 were included. A search of medical records and direct patient contact were performed to obtain swallowing function at multiple time points. Persistently poor swallowing at 2 year after surgery was the primary outcome measure. Two year swallowing outcomes stratified by tumor site and T stage are presented.Results:One hundred eighteen patients met criteria for the study (median follow‐up 53.9 months). There were 44 T1's, 41 T2's, 23 T3's and 10 T4's. Forty seven percent received radiotherapy and 41% received chemoradiotherapy. Ninety‐eight percent underwent neck dissection. Patients tolerated TLM well with 82% enjoying good swallowing at 1 month after surgery. During adjuvant therapy, at 3 months, good swallowing dropped to 55%. At 1 and 2 years after TLM, 89% and 88% of patients had good swallowing function, respectively. At 2 years, 9 patients had persistently poor swallowing function. 93% of patients with T1 through T3 enjoyed good swallowing at 2 years. T4 base of tongue disease was associated with persistently poor swallowing function in multivariate analyses (P = 0.0023), with 40% having good swallowing at 2 years. Preexisting comorbidities and conversion to an open procedure were associated with delayed return of swallowing function, but not with persistently poor swallowing. Seven patients developed late‐onset swallowing dysfunction.Conclusions:Treatment of advanced stage OPC with TLM ± adjuvant therapy results in excellent swallowing outcomes for patients with either T1 to T3 tonsil or T1 to T3 base of tongue resections. A detailed, longitudinal swallowing profile is presented to assist in preoperative counseling.
Anesthetic complications in pediatric patients undergoing cochlear implantation
Authors: Yeh Joseph S. , Mooney Kimberly L. , Gingrich Kevin , Kim Jung T. , Lalwani Anil K. 
Published: September 2011

AbstractObjectives/Hypothesis:Cochlear implantation (CI) is effective in the treatment of childhood sensorineural hearing loss and is associated with minimal surgical complications. We investigated the incidence of anesthetic complications in young patients undergoing general anesthesia for CI.Study Design:Retrospective chart review.Methods:A retrospective chart review of 123 patients younger than 18 years, who underwent CI between 2007 and 2008, was conducted for identification of intra‐ and postoperative anesthesia‐related complications. The relation of collected variable to the complication events was analyzed using logistic regression.Results:Of the 123 CI procedures, eight patients had nine anesthesia‐related complications, yielding a complication rate of 6.5% and included the following: postoperative wheezing/stridor (5 cases), laryngospasm (3 cases), and emesis during inhalational induction (1 case). Divided by age group, 12 patients were <12 months with one complication (8%), 18 patients were between 1 and 2 years with one complication (5.6%), 35 patients were between 2 and 5 years with one complication (3%), 39 patients were between 5 and 12 years with five complications (13%), and 19 patients were older than 12 years with no complication (0%). Logistic regression failed to identify a significant association of any collected variable(s) with the observed complications. The incidence of complications is similar to that previously reported in elderly patients (4.3%) (Pearson χ2, P = .523).Conclusions:General anesthesia is well tolerated by pediatric patients undergoing CI, even under 1 year of age. Significant perioperative complications are primarily respiratory, are usually free of long‐term sequelae, and occur with an incidence similar to other reported age groups.
Red‐Emitting Polymer Microspheres Containing Zinc Porphyrins
Authors: Wang Fei , Ding Kewei , Wu Feipeng 
Published: September 2011

AbstractNovel polymers containing zinc porphyrins are synthesized from 5‐(4‐acryloyloxyphenyl)‐10,15,20‐trisphenylporphyrinate zinc(II) (ZnAOTPP) and NVP. The polymer microspheres are obtained by polymerization in alcoholic solution. TEM images and particle size distribution data show that the morphology and size of the polymer microspheres are controlled by adjusting the molar ratio of ZnAOTPP (RM) to solvent in the polymerization. Compared with ZnAOTPP, zinc porphyrin units (ZnPor units) in polymers exhibit a new absorption band and a new fluorescence emission band due to the formation of porphyrin assemblies, which improve the color purity of their red fluorescence. The luminescence of the polymer microspheres is characterized by fluorescence microscopy.magnified image
Morphology and Properties of Poly(propylene)/Ethylene‐Octene Copolymer Blends Containing Nanosilica
Authors: Lee Sung Hyo , Bailly Mathieu , Kontopoulou Marianna 
Published: September 2011

AbstractThe effect of nanosilica addition on the morphology and mechanical properties of blends of isotactic PP and an ethylene/octene copolymer (EOC) is studied. TEM reveals that the well‐dispersed nanoparticles are localized exclusively in the PP phase. In the presence of a maleated PP compatibilizer addition of nanosilica leads to more finely dispersed EOC domains and a finer co‐continuous morphology. The nanoparticles reduce the rate of coalescence of the dispersed phase domains. The mechanical properties depend on the EOC and PP‐g‐MA content. Tensile and flexural properties are significantly enhanced in the presence of the silica nanoparticles, whereas impact properties are not affected. These enhancements are attributed to the favorable microstructure of the blends.magnified image
Preparation of Ultrafine Ethylene/Propylene/Diene Terpolymer Rubber Fibers by Coaxial Electrospinning
Authors: Liu Li , Zhang Fazhong , Hu Shui , Zhang Liqun , Wen Shipeng 
Published: September 2011

AbstractElastomeric EPDM fibers with diameters of 200–400 nm are prepared by coaxial electrospinning of PVP/EPDM fibers, subsequent vulcanization of the polymers and finally removal of the outer PVP layer using ethanol. The initially applied PVP layer restricts the elastic recovery of the EPDM fibers. The crosslinking density of the EPDM fibers reaches 8.44 × 10−5 mol · cm−3. The original morphology of EPDM is preserved after removing the PVP layer. The ultrafine EPDM fibers are expected to be useful in many fields, such as brittle plastics toughening, as well as applications in extremely high or low temperatures.magnified image
Dimensional mapping: Applying DQR and MDS to explore the perceptions of seniors' role in advertising
Authors: Griessmair Michele , Strunk Guido , Auer‐Srnka Katharina J. 
Published: September 2011

AbstractDimensional qualitative research (DQR) provides a sound conceptual basis for studying complex problems and developing the psychologically sensitive theory needed in marketing. This article proposes dimensional mapping as a method qualified to enhance the application of DQR, contributing to theory development in consumer behavior. The authors show how multidimensional scaling (MDS) can be applied in a mixed method approach for analyzing rich qualitative data. They discuss potential advantages of using MDS in a qualitative– quantitative research framework (e.g., openness to the data, taking participants' perspective, metric data level, accounting for fuzzy data, reliability, and validity) in combination with the BASIC IDS proposed by Cohen (1999b) in order to evaluate the comprehensiveness of the results and derive psychologically meaningful conclusions and implications. The proposed approach is illustrated in an exemplary empirical study investigating the perception of seniors' role in advertising. © 2011 Wiley Periodicals, Inc.
Concentration Dependence of Size, Shape, and Orientation of Copolymers, 1 – Linear Diblock and 4‐arm Hetero Star Polymers
Authors: Nardai Michael M. , Zifferer Gerhard 
Published: September 2011

AbstractBy use of dissipative particle dynamics (DPD) symmetric mictoarm star polymers with four arms and the degenerated case of a linear diblock copolymer (consisting of moderately hostile monomers) are simulated in a selective solvent for concentrations reaching from high dilution to the solvent free bulk. They are analyzed with respect to size, shape, morphology and mobility and compared to their constituent homopolymers. For larger concentrations the shape of pair distribution functions as well as representative snapshots show the development of lamellae, accompanied by characteristic changes of chain/star properties. In addition the influence of the size of the simulation box on the thicknessdand orientation of lamellae in bulk is utilized to study the correlation between chain/star properties anddin detail.magnified image
Beyond nine years of continuous subthalamic nucleus deep brain stimulation in Parkinson's disease
Authors: Zibetti Maurizio , Merola Aristide , Rizzi Laura , Ricchi Valeria , Angrisano Serena , Azzaro Corrado , Artusi Carlo Alberto , Arduino Nichy , Marchisio Alice , Lanotte Michele , Rizzone Mario , Lopiano Leonardo 
Published: September 2011

AbstractDeep brain stimulation of the subthalamic nucleus is an effective treatment for advanced Parkinson's disease. The benefits of bilateral subthalamic stimulation are well documented, and some studies reported outcomes with a follow‐up of 5 to 6 years; nevertheless, few data are available beyond 5 years. We report a long‐term prospective evaluation of 14 consecutive parkinsonian patients, treated by bilateral subthalamic stimulation for at least 9 years. Motor symptoms, activity of daily living, and motor complications were evaluated by means of the Unified Parkinson's Disease Rating Scale, while cognition and mood were assessed with a specific neuropsychological test battery; medication intake, stimulation parameters, comorbidity, and adverse events were also recorded. Patients were evaluated before surgery and at 1, 5, and ≥9 years after surgery. At last follow‐up, deep brain stimulation significantly improved the motor score by 42% compared to baseline, whereas activities of daily living were no longer improved; there was a 39% reduction in the dosage of dopaminergic drugs and a 59% improvement of L‐dopa–related motor complications. The neuropsychological assessment showed that 4 patients (29%) developed a significant cognitive decline over the follow‐up period. These results indicate a persistent effect of deep brain stimulation of the subthalamic nucleus on the cardinal motor symptoms in advanced Parkinson's disease patients in the long‐term; however, a worsening of patients' disability, mainly due to disease progression, was observed. © 2011 Movement Disorder Society
Recovery of mitochondrial function and endogenous antioxidant systems in vitrified bovine oocytes during extended in vitro culture
Authors: Zhao Xue‐Ming , Du Wei‐Hua , Wang Dong , Hao Hai‐Sheng , Liu Yan , Qin Tong , Zhu Hua‐Bin 
Published: September 2011

AbstractThis study was designed to examine the recovery of mitochondrial function and endogenous antioxidant systems in vitrified oocytes during extended incubations. After 16 hr of in vitro maturation, bovine meiosis‐II oocytes were vitrified, and then surviving oocytes were cultured an additional 8 hr. ATP content, ATP synthase activity, expression of ATP synthase F0 subunit 6 (ATP6) and 8 (ATP8) genes, and reactive oxygen species (ROS) levels were investigated in the vitrified oocytes during this additional period (4 or 8 hr). The results showed that: (1) the ATP content and ATP synthase activities in vitrified oocytes at 8 hr post‐warming (754.6 fmol, 25.9 nmol NADH/min/mg) were significantly higher than in oocytes immediately warmed (568.3 fmol, 8.7 nmol NADH/min/mg), but still lower than in control oocytes (901.5 fmol, 30.7 nmol NADH/min/mg); (2) the relative expression of ATP6 and ATP8 was initially down‐regulated in oocytes when they were first warmed, increased by 4 hr post‐warming, and were again down‐regulated by 8 hr post‐warming; (3) ROS levels in oocytes at 0, 4, and 8 hr post‐warming were significantly higher than in control oocytes; and (4) after parthenogenetic activation, the blastocyst rate of oocytes at 8 hr post‐warming (26.7%) was significantly higher than that of oocytes immediately warmed (16.9%). These results indicated that mitochondrial function and endogenous antioxidant systems recovered significantly better in vitrified–thawed bovine oocytes with 8 hr of additional incubation, but they did not achieve the activity levels found in fresh oocytes. Mol. Reprod. Dev. 78:942–950, 2011. © 2011 Wiley Periodicals, Inc.
SA2RAGE: A new sequence for fast B1+‐mapping
Authors: Eggenschwiler Florent , Kober Tobias , Magill Arthur W. , Gruetter Rolf , Marques José P. 
Published: September 2011

AbstractAt high magnetic field strengths (≥3T), the radiofrequency wavelength used in MRI is of the same order of magnitude of (or smaller than) the typical sample size, making transmit magnetic field (B) inhomogeneities more prominent. Methods such as radiofrequency‐shimming and transmit SENSE have been proposed to mitigate these undesirable effects. A prerequisite for such approaches is an accurate and rapid characterization of the B field in the organ of interest. In this work, a new phase‐sensitive three‐dimensional B‐mapping technique is introduced that allows the acquisition of a 64 × 64 × 8 B‐map in ∼20 s, yielding an accurate mapping of the relative B with a 10‐fold dynamic range (0.2–2 times the nominal B). Moreover, the predominant use of low flip angle excitations in the presented sequence minimizes specific absorption rate, which is an important asset for in vivo B‐shimming procedures at high magnetic fields. The proposed methodology was validated in phantom experiments and demonstrated good results in phantom and human B‐shimming using an 8‐channel transmit‐receive array. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Variable flip angle schedules in bSSFP imaging of hyperpolarized noble gases
Authors: Deppe Martin H. , Wild Jim M. 
Published: September 2011

AbstractBalanced steady‐state free precession imaging sequences provide signal‐to‐noise ratio benefits for MRI of hyperpolarized nuclei. Hyperpolarized magnetization decays during the imaging sequence to thermal equilibrium, effectively necessitating imaging in a transient state characterized by nonconstant transverse magnetization and k‐space filtering when using constant flip angles. This work presents an analytical method for calculation of variable flip angle schedules which maintain constant transverse magnetization in balanced steady‐state free precession imaging of hyperpolarized nuclei. The approach is based on direct inversion of the Bloch equations and does not require any numerical optimization. Input parameters are pulse sequence timings and effective relaxation times, which take diffusion of hyperpolarized gas in imaging gradients into account. Provision of constant transverse magnetization is demonstrated in phantom experiments and human lung imaging using hyperpolarized 3He. The benefit of a flat k‐space filter is demonstrated by reduced blurring in 3He and digital phantom data, and high quality 3He ventilation images from human lungs are obtained. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Sonographic assessment of suture artifact obscuring visualization of the digital nerve
Authors: de la Lama Mauricio , Kessler James M. , Umans Hilary R. , Magge Keshav , Liebling Ralph W. , Negron Judith 
Published: September 2011

AbstractIntroduction: The purpose of this study was to grade the severity of sonographic artifact produced by four suture materials and to determine whether these artifacts affect visualization of a digital nerve. Methods: A needle was placed into a pig foot to mimic a normal volar digital nerve. Incisions superficial to the needle were closed with different suture types, specifically nylon (N), chromic (C), vicryl (V), and prolene (P). Sonographic images were obtained using a high‐frequency transducer. Twenty radiology residents and attending physicians graded the severity of artifact and nerve obscuration. Two image types were shown: one suture type per image and a composite image of each suture type, adjacent to one another. Results: Severity of nerve obscuration was as follows: composite image: P = N = V > C; individual images: P > N > V > C. Severity of artifact was: composite image: V = N > P > C; individual image: P > N > V > C. Conclusion: Although all sutures produced artifact, only C produced mild artifact, which did not significantly obscure visualization of the nerve model. Muscle Nerve, 2012
Exponentially fitted discontinuous Galerkin schemes for singularly perturbed problems
Authors: Lombardi Ariel L. , Pietra Paola 
Published: September 2011

AbstractNew discontinuous Galerkin schemes in mixed form are introduced for symmetric elliptic problems of second order. They exhibit reduced connectivity with respect to the standard ones. The modifications in the choice of the approximation spaces and in the stabilization term do not spoil the error estimates. These methods are then used for designing new exponentially fitted schemes for advection dominated equations. The presented numerical tests show the good performances of the proposed schemes. © 2011 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2011
Differential Bone Survivorship and Ontogenetic Development in Guanaco (Lama guanicoe)
Authors: GONZÁLEZ M. E. , ÁLVAREZ M. C. , Massigoge A. , GUTIÉRREZ M. A. , Kaufmann C. A. 
Published: September 2011

ABSTRACTThis paper presents the results of a taphonomic research programme conducted over the past 5 years. The main objective of the programme is to investigate differential survivorship in guanaco (Lama guanicoe) bones, taking into account the ontogenetic development of this species and the densitometric characteristics of its skeletal parts. First, density analysis was carried out on selected bones of modern individuals corresponding to different age classes. Second, two experimental designs were conducted to explore the response of animal bone of different ages to weathering and fluvial transport. The first is a long term experiment that examines the deterioration of skeletal elements from a newborn, a juvenile and an adult modern guanaco exposed to subaerial weathering under controlled conditions. The second experiment examines the hydrodynamic sorting of dry and wet skeletal elements from a newborn, a juvenile, and an adult modern guanaco in an artificial flume under controlled current velocities (15 and 30 cm/s). The main results of the research programme indicate that immature bones have higher hydric transport potential and weather at a faster rate. We propose that this differential bone behaviour is partially related to structural density, as demonstrated by density analysis. These results show age‐related biases in zooarchaeological assemblages affected by taphonomic processes. Copyright © 2011 John Wiley & Sons, Ltd.
High pressure liquid chromatography and pulsed amperometric detection of castanospermine and related alkaloids
Authors: Donaldson M. J. , Broby H. , Adlard M. W. , Bucke C. 
Published: September 2011

AbstractA sensitive, high performance ion‐exchange chromatographic method has been developed for the determination of castanospermine, 1‐deoxynojirimycin, 1‐deoxymannojirimycin and swainsonine. This series of sugar‐shaped alkaloids of plant and microbial origin are potent glycosidase inhibitors. The procedure presented demonstrates their separation on a cation exchange column under isocratic conditions and, following post column addition of 300 Mm sodium hydroxide, detection by pulsed amperometry. The procedure employed a Dionex guard column CG3 with a CS3 separator column and a mobile phase which consisted of 10 Mm hydrocholoric acid.Linear calibration curves for the analysis of these alkaloids have been shown to extend over 2 decades from 10 ng/mL to 20 μg/mL. The method has been compared to previously reported enzymatic assays for the alkaloids. The identity of certain chromatographic peaks has been confirmed by enzyme inhibition studies.The method has been applied to the measurement of natural, low levels of castanospermine found in plant tissues.
Solid state polymerization of poly(L‐lactide): Multiple‐fold increase in molecular weight via an efficient catalyst system
Authors: Katiyar Vimal , Nanavati Hemant 
Published: September 2011

AbstractWe report the synthesis of high molecular weight (MW), high crystallinity (Xc) poly(L‐lactic acid) (PLLA), with improved thermal stability, by solid state polymerization (SSP) of low MW PLLA prepolymer, pre‐PLLA. SSP enabled pre‐PLLA is synthesized by ring opening polymerization (ROP) of L‐lactide using a ternary catalyst complex of L‐lactide, stannous octoate, and L‐lactic acid oligomer (OLLA). We demonstrate that this ROP, although a chain‐growth reaction, yields pre‐PLLA with end‐groups, which enable step growth SSP. MW increases ∼9 fold, with Xc reaching beyond 90%, during the SSP process. Such high values of crystallinity could be due to the synchronization of the crystallization rate with that of the slower and longer lasting step‐growth SSP. Nuclear magnetic resonance spectroscopy confirms that SSP is indeed a step‐growth reaction. In comparison, Zn(OLLA)2 only couples two pre‐PLLA chains during SSP. In addition, the radial spherulite growth rate has been quantified with annealing time of SSP synthesized PLLA. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers