bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Organocatalytic Applications of Imidazol(in)ium‐2‐thiocarboxylates
Authors: Hans Morgan , Wouters Johan , Demonceau Albert , Delaude Lionel 
Published: November 2011

AbstractFive imidazol(in)ium‐2‐thiocarboxylates bearing cyclohexyl, mesityl, or 2,6‐diisopropylphenyl substituents on their nitrogen atoms were prepared from the corresponding imidazol(in)ium chlorides or tetrafluoroborates in a one‐pot, two‐step procedure involving the in situ generation of free N‐heterocyclic carbenes (NHCs) with a strong base followed by trapping with carbonyl sulfide. The resulting NHC·COS zwitterions were isolated in high yields and characterized by IR and NMR spectroscopy. The molecular structure of SIMes·COS was determined by X‐ray diffraction analysis. Experimental data and DFT calculations indicated that the negative charge on the thiocarboxylate anion is preferentially delocalized on the sulfur atom. Thermogravimetric analysis showed that the NHC·COS zwitterions undergo thermolysis at temperatures ranging between 110 and 180 °C in the solid state. They are also rather labile in solution. Unlike the related NHC·CS2 betaines, which are highly stable, crystalline materials, they displayed the same type of behavior as the analogous carboxylate adducts, which readily lose their CO2 moiety upon heating or dissolution. Thus, imidazol(in)ium‐2‐thiocarboxylates acted as convenient NHC precursors in two model organocatalytic transformations. Of the five thiocarboxylates examined, ICy·COS was the most efficient at promoting the acylation of benzyl alcohol with vinyl acetate, whereas SIMes·COS afforded the highest activity in benzoin condensation.
Stability of multiwavelength optical buffers with delay‐oriented scheduling
Authors: Morozov E. , Rogiest W. , De Turck K. , Fiems D. , Bruneel H. 
Published: October 2011

ABSTRACTThis contribution presents the first stability analysis of multiwavelength queueing systems. Results are obtained for a wide class of implementable scheduling disciplines referred to as delay‐oriented disciplines, a class to which for example join the shortest queue belongs. Scheduling is applied as contention resolution in optical switches accommodated with fibre delay lines as means of buffering. The analysis yields sufficient stability conditions for multiwavelength optical buffers with a general fibre‐delay‐line set, renewal input and general service times. Copyright © 2011 John Wiley & Sons, Ltd.
Spectral and power efficiency trade‐offs for multiple‐antenna reception techniques under co‐channel interference
Authors: Ertuğ Özgür 
Published: November 2011

ABSTRACTSpatial receive diversity and beamforming are two competing multiple‐antenna reception strategies for enhancement of spectral and power efficiency of wireless communication systems because they both use the same resource, that is the spatial degrees of freedom. We analyse in this paper ergodic, block‐fading outage and delay‐limited outage spectral efficiencies as well as average bit error rates and service outage probabilities of a hybrid diversity‐beamforming receiver with antenna partitioning over flat Rayleigh‐fading uplink channels under co‐channel interference. The results validated by Monte Carlo simulations decipher the trade‐offs in terms of spectral and power efficiencies in between all‐diversity, hybrid diversity‐beamforming and all‐beamforming reception for different scenarios represented by average signal‐tonoise ratio per path and desired signal‐to‐interference ratio for using these multiple‐antenna reception techniques in interference‐limited wireless communication systems. Copyright © 2011 John Wiley & Sons, Ltd.
High daily fraction dose external radiotherapy for T1 glottic carcinoma: Treatment results and prognostic factors
Authors: Gultekin Melis , Ozyar Enis , Cengiz Mustafa , Ozyigit Gokhan , Hayran Mutlu , Hosal Sefik , Akyol Fadil 
Published: November 2011

AbstractBackgroundThe purpose of this study was to investigate the prognostic factors and treatment results of T1N0M0 glottic laryngeal carcinoma irradiated with 2.3 Gray (Gy) per fraction.MethodsA total of 183 patients with glottic carcinoma treated between June 1998 and January 2007 were retrospectively evaluated. Of the 183 patients, 163 patients (89%) had T1a and 20 patients (11%) had T1b disease. All patients received 2.3 Gy per fraction to a median total dose of 64.4 Gy.ResultsThe median follow‐up was 63 months. The 5‐year overall survival (OS), local control, and cancer‐specific survival rates were 89%, 81%, and 90%, respectively. Multivariate analysis showed overall treatment time and age to be significant prognostic factors for local control and OS. We observed no grade IV or grade V acute toxicity. Trachea–esophageal fistula as late toxicity was observed in only 1 patient.ConclusionsHigh daily fraction scheme seems to be a feasible schedule for early glottic carcinomas. © 2011 Wiley Periodicals, Inc. Head Neck, 2012
Hepatitis C virus reinfection and superinfection among treated and untreated participants with recent infection
Authors: Grebely Jason , Pham Son Truong , Matthews Gail V. , Petoumenos Kathy , Bull Rowena A. , Yeung Barbara , Rawlinson William , Kaldor John , Lloyd Andrew , Hellard Margaret , Dore Gregory J. , White Peter A. 
Published: October 2011

Abstract

The purpose of the study was to evaluate reinfection and superinfection during treatment for recent hepatitis C virus (HCV). The Australian Trial in Acute Hepatitis C (ATAHC) was a prospective study of the natural history and treatment of recent HCV. Reinfection and superinfection were defined by detection of infection with an HCV strain distinct from the primary strain (using reverse-transcription polymerase chain reaction [RT-PCR] and subtype-specific nested RT-PCR assays) in the setting of spontaneous or treatment-induced viral suppression (one HCV RNA <10 IU/mL) or persistence (HCV RNA >10 IU/mL from enrollment to week 12). Among 163 patients, 111 were treated, 79% (88 of 111) had treatment-induced viral suppression, and 60% (67 of 111) achieved sustained virological response. Following treatment-induced viral suppression, recurrence was observed in 19% (17 of 88), including 12 with relapse and five with reinfection (4.7 cases per 100 person-years [PY], 95% confidence interval [CI]: 1.9, 11.2). Among 52 untreated patients, 58% (30 of 52) had spontaneous viral suppression and recurrence was observed in 10% (3 of 30), including two with reinfection. Following reinfection, alanine aminotransferase (ALT) levels >1.5× the upper limit of normal were observed in 71% (5 of 7). Among 37 with persistence, superinfection was observed in 16% (3 of 19) of those treated and 17% (3 of 18) of those untreated. In adjusted analysis, reinfection/superinfection occurred more often in participants with poorer social functioning at enrollment and more often in those with ongoing injecting drug use (IDU). Conclusion: Reinfection and superinfection can occur during treatment of recent HCV and are associated with poor social functioning and ongoing IDU. ALT levels may be a useful clinical marker of reexposure. (Hepatology 2012)
MTHFR polymorphisms, folate intake and carcinogen DNA adducts in the lung
Authors: Lee Mi‐Sun , Asomaning Kofi , Su Li , Wain John C. , Mark Eugene J. , Christiani David C. 
Published: November 2011

AbstractThe methylenetetrahydrofolate reductase (MTHFR) genes and folate in one‐carbon metabolism are essential for DNA methylation and synthesis. However, their role in carcinogen DNA damage in target lung tissue, a dosimeter for cancer risk, is not known. Our study aimed to investigate the association between genetic and nutritional one‐carbon metabolism factors and DNA adducts in target lung. Data on 135 lung cancer cases from the Massachusetts General Hospital were studied. Genotyping was completed for MTHFR C677T (rs1801133) and A1298C (rs1801131). Information on dietary intake for one‐carbon related micronutrients, folate and other B vitamin was derived from a validated food frequency questionnaire. DNA adducts in lung were measured by 32P‐postlabeling. After adjusting for potential confounders, DNA adduct levels in lung significantly increased by 69.2% [95% confidence interval (CI), 5.5% to 171.5%] for the MTHFR 1298AC+CC genotype. The high risk group, combining the A1298C (AC+CC) plus C677T (CT+TT) genotypes, had significantly enhanced levels of lung adducts by 210.7% (95% CI, 21.4% to 695.2%) in contrast to the A1298C (AA) plus C677T (CC) genotypes. Elevation of DNA adduct was pronounced—111.3% (95% CI, −3.0 to 360.5%) among 1298AC+CC patients, who consumed the lowest level of folate intake as compared to 1298AA individuals with highest tertile of intake. These results indicate that DNA adducts levels are influenced by MTHFR polymorphisms and low folate consumption, suggesting an important role of genetic and nutritional factors in protecting DNA damage from lung carcinogen in at‐risk populations.
Formation of dopamine quinone‐DNA adducts and their potential role in the etiology of Parkinson's disease
Authors: Zahid Muhammad , Saeed Muhammad , Yang Li , Beseler Cheryl , Rogan Eleanor , Cavalieri Ercole L. 
Published: November 2011

AbstractThe neurotransmitter dopamine is oxidized to its quinone (DA‐Q), which at neutral pH undergoes intramolecular cyclization by 1,4‐Michael addition, followed by oxidation to form leukochrome, then aminochrome, and finally neuromelanin. At lower pH, the amino group of DA is partially protonated, allowing the competitive intermolecular 1,4‐Michael addition with nucleophiles in DNA to form the depurinating adducts, DA‐6‐N3Ade and DA‐6‐N7Gua. Catechol estrogen‐3,4‐quinones react by 1,4‐Michael addition to form the depurinating 4‐hydroxyestrone(estradiol)‐1‐N3Ade [4‐OHE1(E2)‐1‐N3Ade] and 4‐OHE1(E2)‐1‐N7Gua adducts, which are implicated in the initiation of breast and other human cancers. The effect of pH was studied by reacting tyrosinase‐activated DA with DNA and measuring the formation of depurinating adducts. The most adducts were formed at pH 4, 5, and 6, and their level was nominal at pH 7 and 8. The N3Ade adduct depurinated instantaneously, but N7Gua had a half‐life of 3 H. The slow loss of the N7Gua adduct is analogous to that observed in previous studies of natural and synthetic estrogens. The antioxidants N‐acetylcysteine and resveratrol efficiently blocked formation of the DA‐DNA adducts. Thus, slightly acidic conditions render competitive the reaction of DA‐Q with DNA to form depurinating adducts. We hypothesize that formation of these adducts could lead to mutations that initiate Parkinson's disease. If so, use of N‐acetylcysteine and resveratrol as dietary supplements may prevent initiation of this disease. © 2011 IUBMB IUBMB Life, 63(12): 1087–1093, 2011
Second harmonic imaging of plants tissues and cell implosion using two‐photon process in ZnO nanoparticles
Authors: Urban Ben E. , Neogi Purnima B. , Butler Sween J. , Fujita Yasuhisa , Neogi Arup 
Published: November 2011

AbstractThe optical properties of colloidal ZnO nanoparticle (NP) solutions, with size ranging from several nm to around 200 nm, have been tailored to have high optical nonlinearity for bioimaging with no auto‐fluorescence above 750 nm and minimal auto‐fluorescence below 750 nm. The high second harmonic conversion efficiency enables selective tissue imaging and cell tracking using tunable near‐infrared femtosecond laser source ranging from 750‐980 nm. For laser energies exceeding the two‐photon energy of the bandgap of ZnO (half of 3.34 eV), the SHG signal greatly decreases and the two‐photon emission becomes the dominant signal. The heat generated due to two‐photon absorption within the ZnO NPs enable selective cell or localized tissue destruction using excitation wavelength ranging from 710–750 nm. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Syndromes of neurodegeneration with brain iron accumulation (NBIA): An update on clinical presentations, histological and genetic underpinnings, and treatment considerations
Authors: Schneider Susanne A. , Hardy John , Bhatia Kailash P. 
Published: October 2011

AbstractIn recent years, understanding of the syndromes of neurodegeneration with brain iron accumulation (NBIA) has grown considerably. In addition to the core syndromes of pantothenate kinsase–associated neurodegeneration (PKAN, NBIA1) and PLA2G6‐associated neurodegeneration (PLAN, NBIA2), several other genetic causes have been identified. The acknowledged clinical spectrum has broadened, age‐dependent presentations have been recognized, and we are becoming aware of overlap between the different NBIA disorders as well as with other diseases. Autopsy examination of genetically confirmed cases has demonstrated Lewy bodies and/or tangles in some subforms, bridging the gap to more common neurodegenerative disorders such as Parkinson's disease. NBIA genes map into related pathways, the understanding of which is important as we move toward mechanistic therapies. Our aim in this review is to provide an overview of not only the historical developments, clinical features, investigational findings, and therapeutic results but also the genetic and molecular underpinnings of the NBIA syndromes. © 2011 Movement Disorder Society
Undrained shear band in water saturated granular media: A critical revisiting with numerical examples
Authors: Guo Peijun 
Published: November 2011

SUMMARYBy taking into account the continuity of stresses and pore pressure across the boundaries of a shear band, it is theoretically shown that incipient localization may take place in saturated loose contractive sand in the regime of decreasing deviator stress under undrained conditions. The undrained shear band orientation primarily depends on the Poisson's ratio and the dilatancy characteristics of the material. However, under strict isochoric constraint, localization is precluded in dense dilative sand with deviator stress increasing only. If any local volume change takes place with a certain mechanism, undrained shear band would be possible in dense sand, most likely in the regime of decreasing friction angle after the peak friction angle is mobilized. Numerical examples are given to demonstrate the variation of shear band inclinations with void ratios and initial consolidation pressures. Copyright © 2011 John Wiley & Sons, Ltd.
Analysis of the FEBEX multi‐barrier system including thermoplasticity of unsaturated bentonite
Authors: Dupray Fabrice , François Bertrand , Laloui Lyesse 
Published: November 2011

SUMMARYDeep geological repository involving a multibarrier system constitutes one of the most promising options for isolating high‐level radioactive waste from the human environment. To certify the efficiency of waste isolation, it is essential to understand the behaviour of confining geomaterial under a variety of environmental conditions. To this end, results from a near‐to‐real experiment, the full‐scale engineered barriers in situ experiment, are studied by means of a thermo–hydro–mechanical finite element approach, including a consistent thermoplastic constitutive model for unsaturated soils. Laboratory tests are simulated to calibrate model parameters. The results of the numerical simulations are compared with sensor measurements and show the ability of the model to reproduce the main behavioural features of the system. The influence of the hysteretic and temperature‐dependent retention of water on the mechanical response is exhibited. Finally, those results are interpreted in the light of thermoplasticity of unsaturated soils, which reveals the highly coupled and non‐linear characters of the processes encountered. Copyright © 2011 John Wiley & Sons, Ltd.
Improved variational image registration model and a fast algorithm for its numerical approximation
Authors: Chumchob Noppadol , Chen Ke 
Published: November 2011

AbstractIn a multimodal image registration scenario, where two given images have similar features, but noncomparable intensity variations, the sum of squared differences is not suitable for inferring image similarities. In this article, we first propose a new variational model based on combining intensity and geometric transformations, as an alternative to use mutual information and an improvement to the work by Modersitzki and Wirtz (Modersitzki and Wirtz, Lect Notes Comput Sci 4057 (2006), 257–263), and then develop a fast multigrid (MG) algorithm for solving the underlying system of fourth‐order and nonlinear partial differential equations. We can demonstrate the effective smoothing property of the adopted primal‐dual smoother by a local Fourier analysis. Numerical tests will be presented to show both the improvements achieved in image registration quality and MG efficiency. © 2011 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2011
Cell‐free fetal DNA in specimen from pregnant women is stable up to 5 days
Authors: Müller Sina P. , Bartels Iris , Stein Werner , Emons Günter , Gutensohn Kai , Legler Tobias J. 
Published: October 2011

ObjectiveBefore noninvasive prenatal diagnosis on the fetal Rhesus D status (NIPD RhD) can be implemented on a mass‐scale, it is crucial to define requirements regarding sample transport. The aim of this study was to determine the relation between the transport time of samples for NIPD and the concentration of fetal DNA in maternal plasma.MethodWe analyzed qualitative and quantitative data obtained in a previous study performed with real‐time PCR to determine the accuracy of NIPD RhD following two different DNA extraction protocols. The number of days from phlebotomy until freezing of plasma at the study site was recorded and defined as transport time.ResultsNIPD RhD results of 972 specimens were analyzed according to transport time, which varied from a few hours to a maximum of 8 days (median 2 days). No decrease of cell‐free fetal DNA was observed in samples with less than 6 days transport time. There was a pivotal trend to higher cycle threshold values in samples with ≥ 6 days transport time compared with those with ≤ 5 days.ConclusionBecause only a few laboratories offer an NIPD RhD service, we suggest a maximal transport time of 5 days from phlebotomy until freezing at the testing laboratory. Copyright © 2011 John Wiley & Sons, Ltd.
Amniocentesis in twin pregnancies: a systematic review of the literature
Authors: Vink Joy , Fuchs Karin , D'Alton Mary E. 
Published: October 2011

ABSTRACTObjectiveUsing published data, we sought to determine the amniocentesis‐related loss rate in twin gestations.MethodsWe searched the PUBMED database using keywords “amniocentesis”, “twin” and “twins” to identify articles evaluating genetic amniocentesis in twin gestations published from January 1970 to December 2010. Random effects models were used to pool procedure‐related loss rates from included studies.ResultsThe definition of “loss” varied across the 17 studies identified (Table 1). The pooled procedure‐related loss rate at < 24 weeks was 3.5% (95% confidence interval [CI] 2.6‐4.7) (Figure 2). Pooled loss rates at < 28 weeks (Figure 4) and to term (Figure 5) could not be calculated due to unacceptable heterogeneity of available data. Seven studies included a control (no amniocentesis) group and reported a pooled odds ratio for total pregnancy loss among cases of 1.8 (95% CI 1.2‐2.7) (Figure 3). Only 1 study reported procedure‐related loss rates by chorionicity (7.7% among monochorionics vs 1.4% among controls; p 0.02).ConclusionAnalysis of published data demonstrated a pooled amniocentesis‐related loss rate of 3.5% in twin gestations < 24 weeks. Pooled loss rates within other post‐amniocentesis intervals or other gestational age windows and the impact of chorionicity on procedure‐related loss rates cannot be determined from published data. © 2011 John Wiley & Sons, Ltd.
A survey of school psychologists' preparation, participation, and perceptions related to positive behavior interventions and supports
Authors: Sullivan Amanda L. , Long Lori , Kucera Miranda 
Published: November 2011

AbstractPositive behavior interventions and supports are increasingly utilized in school systems throughout the nation, particularly the school‐wide multi‐tiered support framework. Given such trends, and the basis of these practices in psychological principles and research, it is important to identify how school psychologists are trained to contribute to such efforts, their involvement in intervention activities, and their perceptions of this approach. We surveyed a national sample of 557 school psychologists regarding their training, involvement, and perceptions of positive behavior supports. The results indicate that although most respondents had a variety of training experiences in multiple behavior‐related areas, one quarter did not report receiving any training related to school‐wide positive behavior interventions and supports (SWPBIS). Although 35% of school psychologists reported employment in schools implementing SWPBIS, these schools varied in the SWPBIS elements in place. Implications for school psychology training and practice are addressed. © 2011 Wiley Periodicals, Inc.
A knowledge‐based potential highlights unique features of membrane α‐helical and β‐barrel protein insertion and folding
Authors: Hsieh Daniel , Davis Alexander , Nanda Vikas 
Published: October 2011

AbstractOuter membrane β‐barrel proteins differ from α‐helical inner membrane proteins in lipid environment, secondary structure, and the proposed processes of folding and insertion. It is reasonable to expect that outer membrane proteins may contain primary sequence information specific for their folding and insertion behavior. In previous work, a depth‐dependent insertion potential, Ez, was derived for α‐helical inner membrane proteins. We have generated an equivalent potential for TM β‐barrel proteins. The similarities and differences between these two potentials provide insight into unique aspects of the folding and insertion of β‐barrel membrane proteins. This potential can predict orientation within the membrane and identify functional residues involved in intermolecular interactions.
Pyrethroid insecticide tolerance in bean leaf beetle, Cerotoma trifurcata, in the Mississippi Delta
Authors: Musser Fred R , Knighten Katherine S , Smith John F , Catchot Angus L 
Published: November 2011

AbstractBACKGROUND: Pyrethroid insecticides have historically been effective for controlling bean leaf beetles in soybeans. Perceived field efficacy in the Mississippi Delta region has been lower over the past several years. Laboratory and field data were collected to determine whether there has been a reduction in pyrethroid insecticide susceptibility.RESULTS: Laboratory and field data both confirmed that control of bean leaf beetles with pyrethroid insecticides is poorer in the Delta regions of Mississippi and Louisiana than in all other regions tested. However, it was not possible to show that this reduced susceptibility changed over time. Furthermore, insect movement appeared to make insecticide susceptibility regional, so that localized insecticide applications had little impact on the susceptibility of successive generations.CONCLUSION: Lack of field control owing to low efficacy of pyrethroid insecticides against bean leaf beetle populations in the Delta region should be expected. Selection pressure on a regional basis may further decrease efficacy. Carbamate insecticides generally still provide high levels of control. Copyright © 2011 Society of Chemical Industry