bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and characterization of novel poly(acrylamide‐co‐acrylic acid‐co‐2‐hydroxy ethyl actylate) hydrogels: Mathematical approach in investigation of swelling kinetics and diffusion models
Authors: Awasthi Seema , Singhal Reena
Published: October 2011

In this study, a series of poly(acrylamide‐co‐acrylic acid‐co‐2‐hydroxy ethyl actylate) [AM‐co‐AA‐co‐HEA] hydrogels have been synthesized by varying the acrylic acid (AA)content over eightfold in feed in the range of 33.34–93.76% by keeping other monomer constant. These hydrogels were characterized by FTIR, SEM analysis, elemental analysis, residual acrylic acid analysis, network parameters, and dynamic swelling behavior. The swelling study showed that equilibrium swelling ratio was nonlinearly increased with increasing AA content. Interestingly, the equilibrium swelling ratio decreased from 53.42 to 48.52 for 75–80% AA content hydrogel. The swelling data were found to satisfactorily fit Fick's second law, demonstrating that diffusion rate of water uptake was primarily Fickian. From model fitting, it was observed that early model was applicable for first 30% water absorption, and late model was applicable for latter 70% water absorption for increasing AA content from 33.34–90.90%. For 93.76% AA, early‐time model was extended up to first 50% of water absorption and late model was contracted for latter 50% water absorption, indicating that excessive AA content affects the applicability range of early‐time and late‐time diffusion models for water absorption. Etters model was best applicable to all type of hydrogels and followed over all swelling range. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Mesua ferrea L. seed oil based amido‐amine modified nanoclay/epoxy nanocomposites
Authors: Das Gautam , Karak Niranjan
Published: October 2011

Hydrophilic bentonite and organo‐montmorillonite (OMMT) have been modified by using a vegetable oil based amido‐amine compound. The modified nanoclays were characterized by using X‐ray diffraction (XRD) and FTIR techniques. Increase in the basal spacing after the modification was observed in both the cases. Further, Mesua ferrea L. seed oil based sulfonated epoxy resin nanocomposites have been prepared by using these modified nanoclays [3 (w/w) of clay in each case]. The XRD, TEM, SEM, FTIR, and rheological studies confirmed the formation of partially exfoliated nanocomposites. The study also confirmed that hydrophilic bentonite is not suitable nanofiller for the system, though modified bentonite slightly improves the performance characteristics of the pristine polymer. Modified OMMT based nanocomposite shows significant improvement in tensile strength (∼ 1.7 times), scratch hardness (∼ 2 times), gloss (14 units), and thermal stability (18°C) compared to the pristine system. This nanocomposite also exhibit better performance than OMMT based analogous nanocomposite. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Rotation curves of luminous spiral galaxies
Authors: Yegorova I.A. , Babic A. , Salucci P. , Spekkens K. , Pizzella A.
Published: October 2011

We have investigated the stellar light distribution and the rotation curves of high‐luminosity spiral galaxies in the local Universe. The sample contains 30 high‐quality extended Hα and H I rotation curves. The stellar disk scale‐length of these objects was measured or taken from the literature. We find that in the outermost parts of the stellar disks of these massive objects, the rotation curves agree with the Universal Rotation Curve (Salucci et al. 2007), however a few rotation curves of the sample show a divergence (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Protein and RNA engineering to customize microbial molecular reporting
Authors: Gredell Joseph A. , Frei Christopher S. , Cirino Patrick C.
Published: October 2011

Nature takes advantage of the malleability of protein and RNA sequence and structure to employ these macromolecules as molecular reporters whose conformation and functional roles depend on the presence of a specific ligand (an “effector” molecule). By following nature's example, ligand‐responsive proteins and RNA molecules are now routinely engineered and incorporated into customized molecular reporting systems (biosensors). Microbial small‐molecule biosensors and endogenous molecular reporters based on these sensing components find a variety of applications that include high‐throughput screening of biosynthesis libraries, environmental monitoring, and novel gene regulation in synthetic biology. Here, we review recent advances in engineering small‐molecule recognition by proteins and RNA and in coupling in vivo ligand binding to reporter‐gene expression or to allosteric activation of a protein conferring a detectable phenotype. Emphasis is placed on microbial screening systems that serve as molecular reporters and facilitate engineering the ligand‐binding component to recognize new molecules.
Characterization of Organic Contaminants in New York/New Jersey Harbor Sediments Using FTIR‐ATR and Synchrotron FTIR
Authors: Song Zhiguang , Jones Keith W. , Marinkovic Nebojsa , Xiao Xian Ming , Feng Huan , Tchouparova Elli
Published: October 2011

Dredging and remediation of contaminated Harbor sediments requires characterization of organic pollutants. In this paper, we apply a combination of Fourier transform IR attenuated total reflectance (FTIR‐ATR) and synchrotron FTIR techniques to the investigation of sediments and related materials from New York/New Jersey Harbor and other locations. The FTIR techniques give information on the functional groups of the compounds found in the sediments and make possible measurements with a spatial resolution of about 0.015 mm. Comparisons of natural organic materials namely, river and groundwater humic substances, recent marine and lacustrine sediments, and ancient sedimentary kerogen show that contaminated NY/NJ Harbor sediments display a strong and distinct absorption in their IR spectra at 2850–2950 cm−1 identified as a CH stretching band, indicative of the presence of anthropogenic hydrocarbons. We suggest that the presence of this band could be used for rapid screening for the presence of contaminant organic compounds in sediments encountered in dredging operations and/or as an indicator for the efficacy of sediment decontamination technologies used for treatment of dredged material.
Synthesis and Organocatalytic Applications of Imidazol(in)ium‐2‐thiocarboxylates
Authors: Hans Morgan , Wouters Johan , Demonceau Albert , Delaude Lionel
Published: November 2011

Five 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

This 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

Spatial 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

Background

The 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.

Methods

A 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.

Results

The 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.

Conclusions

High 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

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)
Corporal Punishment and Child Behavioural and Cognitive Outcomes through 5 Years of Age: Evidence from a Contemporary Urban Birth Cohort Study
Authors: MacKenzie Michael J. , Nicklas Eric , Waldfogel Jane , Brooks‐Gunn Jeanne
Published: October 2011

This study examined the prevalence and determinants of spanking of children at 3 years of age and the associations between spanking and externalizing behaviour and receptive verbal ability at age 5 years. Overall, we find maternal spanking rates of 55.2% and paternal rates of 43.2% at age 3 years. Mothers facing greater stress and those who spanked earlier are more likely to spank at age 3 years, whereas those who report a supportive partner during pregnancy and those who were not US born were less likely to spank. Mothers and fathers in communities where spanking was more normative were more likely to spank. Fathers were less likely to spank daughters at age 3 years. Frequent maternal spanking at age 3 years was associated with externalizing behaviour and receptive vocabulary at age 5 years, controlling for an array of ecological risks, earlier behaviour and verbal capacity. Taking advantage of the large and diverse sample, we explored potential interactions and found no evidence that race, parental warmth, normativeness or child gender moderated the association between spanking and externalizing or receptive vocabulary. These findings add to the literature on negative consequences associated with a widely endorsed parenting practice and highlight the need for research that explores alternative effective discipline practices and addresses parent questions of what else they could, or even should, be doing. Copyright © 2011 John Wiley & Sons, Ltd.
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

The 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

The 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

The 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

In 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

By 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

Deep 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

In 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

Objective

Before 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.

Method

We 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.

Results

NIPD 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.

Conclusion

Because 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

Objective

Using published data, we sought to determine the amniocentesis‐related loss rate in twin gestations.

Methods

We 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.

Results

The 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).

Conclusion

Analysis 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

Positive 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

Outer 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

BACKGROUND: 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
Tunable electroluminescence from low‐threshold voltage LED structure based on electrodeposited Zn1−xCdxO‐nanorods/p‐GaN heterojunction
Authors: Pauporté Th. , Lupan O. , Viana B.
Published: October 2011

Violet light‐emitting diode (LED) structures based on Cd‐alloyed zinc oxide (Zn1−xCdxO) nanorods (NRs)/p‐GaN heterojunction have been fabricated by epitaxial electrodeposition at low temperatures in an aqueous soft bath followed by a mild thermal annealing. The ultraviolet (UV) room‐temperature emission peak at around 397 nm with a full width at half‐maximum (FWHM) of 10 nm observed from pure ZnO‐NRs/p‐GaN at room temperature was shifted to 417 nm with FWHM of 14 nm by employing a Zn0.92Cd0.08O‐NRs/p‐GaN heterojunction. The emission threshold voltage was low at about 5.0 V and the electroluminescence (EL) intensity rapidly increased with the applied forward‐bias voltage. The emission wavelength increased with the Cd content in the alloy. The EL physics mechanism in LED structures of the heterojunctions is discussed.
Coherent imaging at the Diamond beamline I13
Authors: Rau Christoph , Wagner Ulrich , Pešić Zoran , De Fanis Alberto
Published: October 2011

The Diamond beamline I13 for imaging and coherence applications is dedicated to hard X‐ray imaging on the micro and nano‐lengthscale. Two independent stations will be operated in a separate building at a distance of 250 m from the source. The imaging branch will perform in‐line phase contrast imaging and tomography over a large field of view in the 6–35 keV energy range. In addition it will be possible to switch to full‐field microscopy with 50 nm spatial resolution. Other microscopies will be developed according to the scientific needs. Resolution beyond the limitations given by the detector and X‐ray optics will be achieved on the ‘coherence’ branch. Techniques working in the far field such as Coherent X‐Ray Diffraction and other Coherent Diffraction Imaging techniques such as ptychography will be implemented. Typical applications cover different fields such as bio‐medicine, materials science, geo‐ and astrophysics or even cultural heritage. The beamline hosts a number of innovative features such as the so‐called ‘mini‐beta’ layout for electron optics in the storage ring or new concepts for beamline instrumentation. The stations will be operational in 2011.
Analysis of resonant MEMS based on high‐electron mobility transistor‐like structure
Authors: Khmyrova Irina , Yamase Ryosuke , Watanabe Norikazu , Maeda Takao , Shestakova Elena , Polushkin Evgeny , Kovalchuk Anatoly , Shapoval Sergei
Published: November 2011

We develop an analytical model for the resonant MEMS with electrical readout in which electrostatically actuated micromachined cantilever oscillates over the two‐dimensional electron gas (2DEG) channel and controls the current flowing along it. The model accounts for the impact of electric field fringing on spatial distribution of sheet electron density along the 2DEG channel.

Nonuniform spatial distribution of sheet electron density results in distributed resistance of the 2DEG channel. Amplitude of the ac component of the source‐drain current is evaluated and compared with that one estimated using ideal model without fringing. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Impurity‐band conduction in polycrystalline films of GaSb and GaSbAs grown by molecular‐beam deposition
Authors: Kajikawa Y. , Okamura K.
Published: November 2011

Polycrystalline films of undoped GaSb, GaSb0.86As0.14, and GaSb0.8As0.2 were grown on glass substrates by molecular‐beam deposition. Hall‐effect measurements were performed in the temperature range of 10‐400 K. Temperature dependences of concentration and mobility of holes at low temperatures were well explained in terms of two‐band conduction consisting of impurity‐band and valence‐band conduction which is limited predominantly by potential barriers at grain boundaries. The procedure for analyzing the Hall‐effect data is extended to be applicable to the sample involving not only the impurity band but also an additional deep acceptor level as well as a compensating donor level, so that the experimental results at high temperatures can also be well simulated. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Institutionalist Implications of the General Systems Theory: The Societal Role of the Market
Authors: Valentinov Vladislav
Published: October 2011

This paper examines how the general systems theory informs institutionalism, a strand of heterodox economic theory founded by Thorstein Veblen that is marked by a critical attitude towards the operation of real‐world markets. Focusing on Laszlo's systems philosophy and Bogdanov's Tektology, the paper shows that the general systems theory supports the institutionalist critique of the market but is more explicit about the significance of the market in ensuring the material self‐provisioning aspect of society. In line with the institutionalist critique, both Bogdanov and Laszlo share the concern that the market may not deliver the appropriate level of systemic integration within society, nor between society and the encompassing nature. However, both Bogdanov and Laszlo are shown to moderate the institutionalist critique by emphasizing the market's stabilizing and protective role, which is needed to safeguard the maintenance of social and technological complexity. Copyright © 2011 John Wiley & Sons, Ltd.
Review of massively parallel DNA sequencing technologies
Authors: Moorthie Sowmiya , Mattocks Christopher J. , Wright Caroline F.
Published: October 2011

Since the development of technologies that can determine the base-pair sequence of DNA, the ability to sequence genes has contributed much to science and medicine. However, it has remained a relatively costly and laborious process, hindering its use as a routine biomedical tool. Recent times are seeing rapid developments in this field, both in the availability of novel sequencing platforms, as well as supporting technologies involved in processes such as targeting and data analysis. This is leading to significant reductions in the cost of sequencing a human genome and the potential for its use as a routine biomedical tool. This review is a snapshot of this rapidly moving field examining the current state of the art, forthcoming developments and some of the issues still to be resolved prior to the use of new sequencing technologies in routine clinical diagnosis.
Fish Oil Normalizes Plasma Glucose Levels and Improves Liver Carbohydrate Metabolism in Rats Fed a Sucrose‐Rich Diet
Authors: Hein Gustavo J. , Chicco Adriana , Lombardo Yolanda B.
Published: November 2011

A sucrose‐rich diet (SRD) induces insulin resistance and dyslipidemia with impaired hepatic glucose production and gluconeogenesis, accompanied by altered post‐receptor insulin signaling steps. The aim of this study was to examine the effectiveness of fish oil (FO) to reverse or improve the impaired hepatic glucose metabolism once installed in rats fed 8 months a SRD. In the liver of rats fed SRD in which FO replaced corn‐oil during the last 2 months, as dietary fat, several key enzyme activities and metabolites involved in glucose metabolisms (phosphorylation, glycolysis, gluconeogenesis and oxidative and non oxidative glucose pathway) were measured. The protein mass levels of IRS‐1 and αp85 PI‐3K at basal conditions were also analyzed. FO improved the altered activities of some enzymes involved in the glycolytic and oxidative pathways observed in the liver of SRD fed rats but was unable to restore the impaired capacity of glucose phosphorylation. Moreover, FO reversed the increase in PEPCK and G‐6‐Pase and reduced the G‐6‐Pase/GK ratio. Glycogen concentration and GSa activity returned to levels similar to those observed in the liver of the control‐fed rats. Besides, FO did not modify the altered protein mass levels of IRS‐1 and αp85 PI‐3K. Finally, dietary FO was effective in reversing or improving the impaired activities of several key enzymes of hepatic carbohydrate metabolism contributing, at least in part, to the normalization of plasma glucose levels in the SRD‐fed rats. However, these positive effects of FO were not observed under basal conditions in the early steps of insulin signaling transduction.
Influence of age and fall type on head injuries in infants and toddlers
Authors: Ibrahim Nicole G. , Wood Joanne , Margulies Susan S. , Christian Cindy W.
Published: November 2011

Age‐based differences in fall type and neuroanatomy in infants and toddlers may affect clinical presentations and injury patterns.

Objective

Our goal is to understand the influence of fall type and age on injuries to help guide clinical evaluation.

Design/Setting/Participants

Retrospectively, 285 children 0–48 months with accidental head injury from a fall and brain imaging between 2000 and 2006 were categorized by age (infan ≤ 1 year and toddler = 1–4 years) and fall type: low (≤3 ft), intermediate (>3 and <10 ft), high height falls (≥10 ft) and stair falls.

Outcome Measures

Clinical manifestations were noted and head injuries separated into primary (bleeding) and secondary (hypoxia, edema). The influence of age and fall type on head injuries sustained was evaluated.

Results

Injury patterns in children <4 years varied with age. Despite similar injury severity scores, infants sustained more skull fractures than toddlers (71% vs. 39%). Of children with skull fractures, 11% had no evidence of scalp/facial soft tissue swelling. Of the patients with primary intracranial injury, 30% had no skull fracture and 8% had neither skull fracture nor cranial soft tissue injury. Low height falls resulted in primary intracranial injury without soft tissue or skull injury in infants (6%) and toddlers (16%).

Conclusions

Within a given fall type, age‐related differences in injuries exist between infants and toddlers. When interpreting a fall history, clinicians must consider the fall type and influence of age on resulting injury. For young children, intracranial injury is not always accompanied by external manifestations of their injury.
Assessing non-normal effects in thermoacoustic systems with mean flow
Authors: Wieczorek K. , Sensiau C. , Polifke W. , Nicoud F.
Published: November 2011

In this paper, non-normal interactions in a thermoacoustic system are studied, using a low-order expansion of the state variables in terms of eigenmodes. The thermoacoustic eigenmodes are determined as solutions of the Helmholtz equation or the linearized Euler equations, respectively, in the presence of a time-lagged heat source. Subsequently, non-normal effects are evaluated in a post-processing analysis based on the computed eigenmodes. In the case where the eigenmode analysis is based on the linearized Euler equations, effects of a non-zero mean flow velocity can be taken into account. The energy associated with the eigenmodes may then contain contributions of convected entropy and vorticity modes as well as the acoustic field. The notion of transient growth of perturbation energy is thus extended from an expression based on the classical acoustic energy density to a form based on a generalized disturbance energy. The expansion in terms of eigenmodes is computationally efficient, making the approach potentially applicable to complex, 3D configurations including non-trivial boundary conditions and spatio-temporal distributions of heat release fluctuations. In the present paper, the method is applied to a 1D configuration that consists of a duct including a 1D heat source, followed by a choked isentropic nozzle. It is shown that for such a case, it is essential to include the contribution of entropy perturbations in the calculation of the optimal initial perturbation and the maximum transient energy growth. Subsequently, the impact of increasing mean flow Mach number and increasing strength of flame/acoustic interaction on non normal effects is assessed in a parameter study.
Photoluminescence of deep defects involving transition metals in Si: New insights from highly enriched 28Si
Authors: Steger M. , Yang A. , Sekiguchi T. , Saeedi K. , Thewalt M. L. W. , Henry M. O. , Johnston K. , Riemann H. , Abrosimov N. V. , Churbanov M. F. , Gusev A. V. , Kaliteevskii A. K. , Godisov O. N. , Becker P. , Pohl H.-J.
Published: November 2011

Deep luminescence centers in Si associated with transition metals have been studied for decades, both as markers for these deleterious contaminants, as well as for the possibility of efficient Si-based light emission. They are among the most ubiquitous luminescence centers observed in Si, and have served as testbeds for elucidating the physics of isoelectronic bound excitons, and for testing ab-initio calculations of defect properties. The greatly improved spectral resolution resulting from the elimination of inhomogeneous isotope broadening in the recently available highly enriched 28Si enabled the extension of the established technique of isotope shifts to the measurement of isotopic fingerprints, which reveal not only the presence of a given element in a luminescence center, but also the number of atoms of that element. This has resulted in many surprises regarding the actual constituents of what were thought to be well-understood deep luminescence centers. Here we summarize the available information for four families of centers containing either four or five atoms chosen from (Li, Cu, Ag, Au, Pt). The no-phonon transition energies, their isotope shifts, and the local vibrational mode energies presented here for these deep centers should prove useful for the still-needed theoretical explanations of their formation, stability and properties.
Spin-polarized transport through a parallel triple-quantum-dot device: Blockade effects of Rashba spin-orbit interaction and Coulomb interaction
Authors: Fu Hua-Hua , Yao Kai-Lun
Published: November 2011

Charge and spin-polarized transport through a parallel coupled triple-quantum-dot (tQD) device with common source and drain electrodes has been theoretically investigated by means of the nonequilibrium Green’s function formalism. By introducing a local Rashba spin-orbit interaction on a QD and considering an Aharonov-Bohm flux through the tQD ring, we find that there is a spin-polarized current (Is) occurring and oscillating in its current-voltage curves. The direction of the spin polarization can be inverted frequently by altering applied bias voltage (V), which turns to result in a multiple negative differential resistance feature in the relationship of (Is-V). Interestingly, a new type of blockade effect, i.e., spin-orbit blockade, different from the Coulomb blockade detected before, has been observed in the charge and spin-polarized currents through the tQD device. Through adjusting these two blockade effects, the tQD device can be designed and applied in the area of spin-current rectifiers and multiple-value logical devices with desirable spin-transport properties.
Vacancy formation energy in Czochralski-grown Si crystals determined by a quenching method
Authors: Suezawa Masashi , Fukata Naoki , Vanhellemont Jan , Yonenaga Ichiro
Published: November 2011

The vacancy formation energy in Czochralski-grown (Cz-) Si crystals was determined by applying a new quenching method. In this method, the optical absorption due to hydrogen atoms bound to vacancies is measured to estimate the vacancy concentration. In contrast with floating-zone grown Si crystals, one more optical absorption peak other than 2223 cm−1 peak was observed at about 2120 cm−1. The defects responsible for the 2120 cm−1 peak are proposed to be VOH4 and VO2H4, inferring from the Voronkov-Falster model on grown-in defects in Cz-Si crystals. The vacancy formation energy estimated from the quenching temperature dependence of the integrated intensity of the 2120 cm−1 peak is about 2.3 eV. After taking the contribution from vacancies generated in the perfect crystal part into account, the formation energy is determined to be approximately 1.5 eV. Such small formation energy compared to that (3.85 eV) in high-purity crystals is thought to be due to a strong interaction between a vacancy and an oxygen atom.