bluuebunny/crossref_metadata_2025 huggingface dataset:
Characteristics of annual runoff variation in major rivers of China
Authors: Li Donglong , Wang Wensheng , Hu Shixiong , Li Yueqing
Published: October 2011

The statistical properties of annual runoff in major rivers of China are studied based on the theory of stochastic process and technology of time series analysis. These properties include the characteristics of intra‐annual and inter‐annual variations of runoff, trends, abrupt changes and periodicities. The new findings from the intensive calculations and appropriate analysis of data in longer period are as follows: (i) compared with the nonuniformity of intra‐annual runoff before 1980, the nonuniformity of intra‐annual runoff in China generally decreased after 1980, except for Huaihe River and Songhua River; (ii) compared with the annual runoff before 1980, the annual runoff in China generally decreased after 1980 except for WangJiaba station in Huaihe River and Ha‐Erbin station in Songhua River; the frequency of continuous low flow and continuous high flow in Haihe River and the downstream of Yellow River is higher than those in other rivers in China; (iii) annual runoff shows a downward trend in major rivers of China especially in Haihe River, Liao River and the midstream and downstream of Yellow River; (iv) there exist certain abrupt changes of annual runoff in major rivers of China; the abrupt change‐points are different among different river basins; and (v) almost periodicities of annual runoff sequences in major rivers of China are generally 20 years below, that is, 3~7 and 12~20 years. The reasons for these changes are mainly caused by climate change and human activities. Copyright © 2011 John Wiley & Sons, Ltd.
Sapovirus as a gastrointestinal pathogen in febrile pediatric patients with cancer
Authors: Moser Olga , Lück Sabrina , Dilloo Dagmar , Eis‐Hübinger Anna Maria , Simon Arne
Published: October 2011

Human caliciviruses are the second most common cause of viral gastroenteritis after rotavirus in children. Unlike norovirus, sapovirus infection is less well characterized and defined in the clinical setting of gastrointestinal disease, and there are no reports of sapovirus infections in pediatric oncology patients receiving chemotherapy treatment. Stool samples from all pediatric oncology patients presenting with fever and diarrhea at one pediatric oncology unit were tested prospectively for sapovirus by real‐time reverse transcription‐PCR sapovirus genogrouping was performed by nested PCR. Sapovirus was detected in 2 of 100 stool specimens prospectively sampled from 58 symptomatic pediatric oncology inpatients between December 2008 and September 2009. Both patients received low‐dose chemotherapy for their underlying conditions at the time of infection with sapovirus. Genogrouping of the viruses showed the presence of a GI.1 strain and GII.3 strain, unlike the most common GI.2 strain responsible for outbreaks in different European countries. The contribution of sapovirus infection to the morbidity of pediatric cancer patients and its potential for nosocomial spread is discussed. Sapovirus, an often unrecognized pathogen, should be considered along with other viruses in pediatric cancer patients suffering from gastrointestinal disease. J. Med. Virol. 83:2233–2236, 2011. © 2011 Wiley Periodicals, Inc.
Molecular epidemiology of measles virus in Iran 2009–2010: First detection of measles genotype H1
Authors: Salimi Vahid , Mokhtari‐Azad Talat , Abbasi Simin , NoroozBabaei Zahra , Soltan‐Shahi Rambod , Zahraie Mohsen , Bont Louis , Gouya Mohammad Mehdi
Published: October 2011

Measles virus (MV) genotyping is an important component of measles surveillance in the context of monitoring immunization program effectiveness and documenting MV elimination. The molecular epidemiology and genetic variability of circulating MV strains in Iran during the 2009–2010 were studied in consecutive MV isolates from throat swab and urine. Sequence information obtained from 41 cases based on the 456 nucleotides of the most variable region of the C‐terminal part of the N‐protein revealed that these sequences belonged to two different genotypes. This is the first description of the genetic characterization of sporadic MV genotype H1 cases in northern Iran. Cases were probably linked to MV importation from distant parts of Asia. The genotype H1 has not been detected in the Eastern Mediterranean Region. In addition, both sequence analysis and epidemiologic data indicated that the more recently detected genotype D4 viruses in Iran were related very closely to viruses that were detected in Pakistan, suggesting that these viruses may have been imported from Pakistan. J. Med. Virol. 83:2200–2207, 2011. © 2011 Wiley Periodicals, Inc.
Genetic diversity of echovirus 30 involved in aseptic meningitis cases in Brazil (1998–2008)
Authors: dos Santos Gina Peres Lima , da Costa Eliane Veiga , Tavares Fernando Neto , da Costa Luciana Jesus , da Silva Edson Elias
Published: October 2011

Aseptic meningitis is one of the most common neurological disorders caused by enteroviruses. Among them, Echovirus 30 (E30) is described as the main etiological agent of many outbreaks and sporadic cases. This study investigated the genomic variability of E30 isolated from the cerebrospinal fluid (CSF) of aseptic meningitis cases that occurred from 1998 to 2008 in Brazil. Over a 10‐year period (1998–2008), 302 non‐polio enteroviruses were isolated, of which 177 were identified as E30 (58.6%). Phylogenetic analysis of the complete VP1 gene (876 nt) of 48 E30 isolates was performed and compared with additional Brazilian and foreign strains. E30 VP1 sequences segregated into three distinct major groups and seven subgroups, which were linked to the isolation year. In general, sequence divergence among E30 strains ranged from 0.2% to 13.8%. A common direct ancestor for this set of E30 strains was not defined. Brazilian isolates from Group I were related genetically to a 1997 USA isolate and both may have a common origin. Group III representatives showed close relationship to the 2007 Argentinean isolates. The present results complement existing data on the molecular characterization and genetic variability of E30 and may contribute to the understanding of the epidemiology of aseptic meningitis in the region. J. Med. Virol. 83:2164–2171, 2011. © 2011 Wiley Periodicals, Inc.
Clinical features and prognosis of hepatocellular carcinoma with respect to pre‐S deletion and basal core promoter mutations of hepatitis B virus Genotype C2
Authors: Ryu Han Jak , Kim Do Young , Park Jun Yong , Chang Hye Young , Lee Myoung Ha , Han Kwang‐Hyub , Chon Chae Yoon , Ahn Sang Hoon
Published: October 2011

Few studies have reported on the clinical characteristics of hepatocellular carcinoma (HCC) at the time of diagnosis with regard to pre‐S and basal core promoter (BCP) mutations. In this study, the clinical features and prognosis of 126 Korean HCC patients were examined with respect to pre‐S deletion and BCP mutations of hepatitis B virus. The proportion of HCC patients according to tumor‐node‐metastasis stage are as follows: 8.7% in stage I, 31% in stage II, 30.2% in stage III, 21.4% in stage IV‐A, and 8.7% in stage IV‐B. Overall, 40.5% of HCC patients were treated by surgery or ablation, 59.5% by other methods. Patients were divided according to pre‐S deletion and BCP mutations (103 without pre‐S deletion, 23 with pre‐S deletion; 44 without BCP mutation, 82 with BCP mutation). The tumor characteristics and prognosis were evaluated between the groups, including size, number, type, vessel invasion, portal vein thrombosis, and metastasis. No significant difference in tumor characteristics between the HCC patients with pre‐S deletion was observed, compared with the HCC patients without pre‐S deletion. In contrast, the survival rate was lower in those with pre‐S deletion than in those without it (P = 0.024). No difference in tumor characteristics was found in non‐BCP and BCP mutation patients. Unlike the pre‐S deletion group, no difference was observed in survival rate between the non‐BCP and BCP patients. In conclusion, pre‐S deletion and BCP mutations did not affect the initial tumor features. However, pre‐S deletion was an independent risk factor affecting HCC survival. J. Med. Virol. 83:2088–2095, 2011. © 2011 Wiley Periodicals, Inc.
The high incidence of JC virus infection in urothelial carcinoma tissue in Taiwan
Authors: Shen Cheng‐Huang , Wu Jiann‐Der , Hsu Cheng‐Da , Jou Yeong‐Chin , Lin Chang‐Te , Wang Meilin , Wu Shu‐Fen , Chan Michael W.Y. , Chiang Ming‐Ko , Fang Chiung‐Yao , Chang Deching
Published: October 2011

Human polyomaviruses, JC virus (JCV) and BK virus (BKV), usually remain latent in kidney and urothelial tissue after primary infection. Infection with human polyomavirus has still not been correlated conclusively with malignancy of kidney and urothelial tissue. The present study investigated further the possible relationship between JCV/BKV infection and urothelial carcinoma. Tissue samples were examined from 33 urothelial carcinomas and 5 renal cell carcinomas for JCV/BKV infection, using nested PCR with primers common to both JCV and BKV. The viral genotypes were further verified by endonuclease digestion and DNA sequencing following the PCR. In addition, immunohistochemistry and Western blotting were also performed to detect viral large tumor protein (LT) and the late capsid protein (VP1) in the tissue samples. The results from nested PCR showed that 90.1% (30/33) of the urothelial carcinomas samples and all of the renal cell carcinomas samples (5/5) were JCV DNA positive. Both archetypal and re‐arranged JCV genotypes were detected. On the other hand, BKV DNA was detected in only one (3%) of the urothelial carcinoma tissue samples. The immunohistochemical results showed that 30% (10/33) of urothelial carcinoma tissues was stained positive for large tumor antigen (LT). However, the structural protein VP1 was not detectable in any of the tissue samples examined. The present study demonstrated that JCV is highly prevalent in urothelial carcinoma tissue as is the expression of large tumor antigen. Therefore, the findings support the hypothesis that JCV infection is associated with urothelial carcinoma. J. Med. Virol. 83:2191–2199, 2011. © 2011 Wiley Periodicals, Inc.
Influence of mutation of the HFE gene on the progression of chronic viral hepatitis B and C in Moroccan patients
Authors: Ezzikouri Sayeh , Rebbani Khadija , Mostafa Ababou , El feydi Abdellah Essaid , Afifi Rajae , Brahim Ikram , Kitab Bouchra , Benazzouz Mustapha , Kandil Mostafa , Nadifi Sellama , Pineau Pascal , Benjelloun Soumaya
Published: October 2011

The implication of hemochromatosis (HFE) gene mutations in chronic viral hepatitis remains controversial. The aim of the present study was to measure the frequencies of the common HFE gene mutations in Moroccan subjects with chronic viral hepatitis B and C and to assess their influence on the progression of liver disease. H63D and C282Y mutations were screened by the polymerase chain reaction followed by restriction fragment length polymorphism analysis in 170 chronic hepatitis B patients, 168 chronic hepatitis C patients, and 200 healthy controls. A very small proportion of patients infected with hepatitis B virus (HBV) or hepatitis C virus (HCV; 1.8% and none, respectively) were heterozygous for the C282Y mutation, that is, rates not statistically different from those observed in healthy control (2%, P > 0.05). Similarly, the frequency of the H63D allele was not significantly different between HBV (13.8%) or HCV (14.3%) patients and controls (13.5%, P > 0.05). Multivariate analysis showed that carriers of the H63D mutation infected with HBV are at higher risk to progress towards an advanced liver disease when compared with patients infected with HBV with wild‐type (OR = 2.45, 95% CI = 1.07–5.58). In contrast, no association between HFE mutated HCV‐infected patients and an increased risk of disease progression was found (OR = 1.24, 95% CI = 0.61–2.50, P = 0.547). In conclusion, in Morocco the frequency of the HFE C282Y allele is very low and H63D mutation carriage occurs in almost 14% of the patients, a rate similar in chronic hepatitis patients and healthy controls. In the case of chronic hepatitis B, the carriage of the H63D variant represents a risk factor of evolution towards a more active disease. J. Med. Virol. 83:2096–2102, 2011. © 2011 Wiley Periodicals, Inc.
Clonal analysis of hepatitis B viruses among blood donors from Joinville, Brazil: Evidence of dual infections, intragenotype recombination and markers of risk for hepatocellular carcinoma
Authors: Reis Laura M.W. , Soares Marcelo A. , França Paulo H. , Soares Esmeralda A. , Bonvicino Cibele R.
Published: October 2011

Hepatitis B virus (HBV) is classified into seven major genotypes (A–H). Brazil, a country of continental proportions, has three prevailing lineages of HBV genotypes A, D, and F. Distinct HBV genotypes have been associated with differential risk of disease progression. Pre‐S gene deletions and single nucleotide polymorphisms have also been linked to progression to liver diseases. In this study, the molecular epidemiology of HBV was examined in Southern Brazil. The occurrence of multiple HBV infections, HBV recombination, and genetic markers of disease progression were also evaluated. Seventy‐eight persons infected with HBV had their viruses characterized molecularly by nested PCR, DNA sequencing, and phylogenetic inference. Multiple infections and recombinant viruses were evaluated by clonal and bootscanning analyses. The vast majority (96%) of the strains belonged to different D subgenotypes. Three of the four strains with unresolved genotypic classification showed evidence of dual infections with distinct D subgenotypes by clonal analysis. There was also evidence of intragenotype mosaic viruses. While four viruses had pre‐S deletions as major variants, another two displayed minor variants with such characteristics. One strain carried the F141L mutation, associated recently with increased risk of hepatocellular carcinoma. These results emphasize the need for monitoring HBV genotype distribution around South America, as well as for the presence of genetic markers of disease progression in subjects diagnosed with HBV recently. J. Med. Virol. 83:2103–2112, 2011. © 2011 Wiley Periodicals, Inc.
Post‐radiation sarcomas. Clinical outcome of 52 Patients
Authors: Mavrogenis Andreas F. , Pala Elisa , Guerra Giovanni , Ruggieri Pietro
Published: October 2011

Background

Previous studies reported on post‐radiation sarcomas. However, the incidence, latency from radiation therapy, treatment, and survival has been difficult to evaluate. We performed a retrospective, single‐institutional study to determine these factors for post‐radiation sarcomas.

Materials and Methods

We retrospectively studied 52 patients with post‐radiation sarcomas diagnosed and treated from 1985 to 2011. The mean age was 49 years; 45 patients had bone and 7 soft tissue sarcoma. The mean follow‐up was 45 months. Survival was analyzed with respect to age at diagnosis, type (bone vs. soft tissue), histology, location (trunk vs. extremities), size, and surgical treatment (resection vs. amputation).

Results

The risk of post‐radiation sarcoma was 0.06% at a mean latency of 15 years (3–50 years) after radiation therapy. The most common histology was osteosarcoma followed by malignant fibrous histiocytoma and fibrosarcoma; all sarcomas were high grade. Survival of the patients with post‐radiation sarcomas was 85% at 1 year, 51% at 2 years, 48% at 3 years, and 45% at 5 years. Univariate predictor of survival was only the type of the sarcoma. No variable was significant in multivariate analysis.

Conclusions

Prognosis of post‐radiation sarcomas is poor; the type of the sarcomas is the only significant variable for survival. J. Surg. Oncol. 2012; 105:570–576. © 2011 Wiley Periodicals, Inc.
A Photocurable Hydrogel/Elastomer Composite Scaffold with Bi‐Continuous Morphology for Cell Encapsulation
Authors: Hayami James W. S. , Waldman Stephen D. , Amsden Brian G.
Published: October 2011

A photocurable two‐phase scaffold with a bi‐continuous morphology was designed and characterized for the repair of load bearing soft tissues. AnN‐methacrylate glycol chitosan (MGC) hydrogel phase was used to distribute the cells and enable cell growth once crosslinked. The second phase, an elastomerprepared from astar‐poly(ε‐caprolactone‐co‐D,L‐lactide) triacrylate, was used to enhance the mechanical properties. Chondrocytes were photocrosslinked within the bi‐continuous scaffolds and proliferated, increased metabolic activity and accumulated extracellular matrix over a 14 d culture period. Also during this time no significant material degradation was observed.

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Positive solutions for mixed problems of singular fractional differential equations
Authors: Agarwal Ravi P. , O'Regan Donal , Staněk Svatoslav
Published: October 2011

We investigate the existence of positive solutions to the singular fractional boundary value problem: \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$^c\hspace{-1.0pt}D^{\alpha }u +f(t,u,u^{\prime },^c\hspace{-2.0pt}D^{\mu }u)=0$\end{document}, u′(0) = 0, u(1) = 0, where 1 < α < 2, 0 < μ < 1, f is a Lq‐Carathéodory function, \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$q > \frac{1}{\alpha -1}$\end{document}, and f(t, x, y, z) may be singular at the value 0 of its space variables x, y, z. Here \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$^c \hspace{-1.0pt}D$\end{document} stands for the Caputo fractional derivative. The results are based on combining regularization and sequential techniques with a fixed point theorem on cones.
Confirmatory factor structure of anxiety and depression: evidence of item variance across childhood
Authors: Boylan Khrista R. , Miller Jessie L. , Vaillancourt Tracy , Szatmari Peter
Published: October 2011

The distinctiveness of anxiety and depressive symptoms in children has previously been questioned based on their high degree of comorbidity, shared risk factors, and treatment response. Developing children may show an unstable presentation of anxiety and depressive symptoms that would complicate interpretation of studies of comorbidity. The present study examined the measurement stability of anxiety and depressive symptoms across time and sex using a large epidemiologic sample of children. A nationally representative cohort of 1329 children (624 girls and 705 boys) aged four to seven in 1994 were drawn from the National Longitudinal Survey of Youth (NLSY). Using eight years of prospective data we examined whether a one or two factor structure of anxiety (five items) and depressive (four items) symptoms would be invariant across time and sex. Despite item variability within each factor across time, confirmatory factor analysis revealed distinct factors for anxiety and depression that were stable across time and sex. Results provide support that covariation between anxiety and depression is not likely the result of measurement overlap. However, items indicating factors of anxiety and depression in the NLSY may not be sufficient to permit developmentally‐sensitive measurement of these factors. Copyright © 2011 John Wiley & Sons, Ltd.
Pseudo‐continuous arterial spin labeling at very high magnetic field (11.75 T) for high‐resolution mouse brain perfusion imaging
Authors: Duhamel Guillaume , Callot Virginie , Tachrount Mohamed , Alsop David C. , Cozzone Patrick J.
Published: October 2011

With the increasing number of transgenic mouse models of human brain diseases, there is a need for a sensitive method that allows assessing quantitative whole brain perfusion within a reasonable scan time. Arterial spin labeling (ASL), an MRI technique that permits the noninvasive quantification of cerebral blood flow, has been used to assess rodents brain perfusion. For mice, the reported experiments performed with continuous or pulsed ASL were challenged by poor multislice capability, limited sensitivity, or quantification issues. Here, the recently proposed pseudo‐continuous ASL strategy, which has shown great promise for human studies, was investigated for mouse brain perfusion imaging at 11.75 T. Pseudo‐continuous ASL was experimentally optimized and compared with a standard flow‐sensitive alternating inversion recovery sequence for sensitivity, robustness, absolute quantification, and multislice imaging capability. A sensitivity gain up to 40% and clear advantages for multislice imaging are obtained with pseudo‐continuous ASL. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Applications of stimulated echo correction to multicomponent T2 analysis
Authors: Prasloski Thomas , Mädler Burkhard , Xiang Qing‐San , MacKay Alex , Jones Craig
Published: October 2011

We propose a multicomponent fitting algorithm for multiecho T2 data which allows for correction of T2 distributions in the presence of stimulated echoes. Tracking the population of spins in many coherence pathways via the iterated method of the Extended Phase Graph algorithm allows for accurate quantification of echo magnitudes. The resulting decay curves allow for correction of errors due to nonideal refocusing pulses as a result of inhomogeneities in the B1 transmit field. Non‐Negative Least Squares fitting is used to quantify the magnitude of T2 components at various T2 values. This method, allowing calculation of the T2 distribution with simultaneous extraction of the refocusing pulse flip angle, requires no change to image acquisition procedures and no extra data input. Validation by means of both simulations and in vivo data shows excellent interscan reproducibility while vastly improving the accuracy of extracted T2 parameters in voxels where poor B1 homogeneity leads to refocusing pulse flip angles significantly less than 180°. Most notably, myelin water fraction values in these regions are found to have increased consistency and accuracy. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.
Linear convergence of an algorithm for computing the largest eigenvalue of a nonnegative tensor
Authors: Zhang Liping , Qi Liqun
Published: October 2011

An iterative method for finding the largest eigenvalue of a nonnegative tensor was proposed by Ng, Qi, and Zhou in 2009. In this paper, we establish an explicit linear convergence rate of the Ng–Qi–Zhou method for essentially positive tensors. Numerical results are given to demonstrate linear convergence of the Ng–Qi–Zhou algorithm for essentially positive tensors. Copyright © 2011 John Wiley & Sons, Ltd.
Preparation and property of 2‐acrylamide‐2‐methylpropanesulfonic acid/acrylamide/sodium styrene sulfonate as fluid loss agent for oil well cement
Authors: Li Huan‐Ming , Zhuang Jia , Liu Han‐Bin , Feng Li , Dong Wenbo
Published: October 2011

A novel terpolymer 2‐acrylamide‐2‐methylpropanesulfonic acid/acrylamide/sodium styrene sulfonate (AMPS/AM/SSS), used as fluid loss agent for oil well cement under high temperature, was prepared with initiator of azobisisobutryamide chloride. The optimum reaction conditions of polymerization were obtained from the orthogonal experiments, reaction temperature 40°C, initiator 0.1 wt%, molar ratio of monomers AMPS/AM/SSS 20/5/1. The structure and performance of terpolymer was characterized with Fourier transform infrared spectrometer, nuclear magnetic resonance hydrogen spectrum, thermogravimetric and simultaneous differential thermal analysis, high‐temperature and high‐pressure water loss meter, and rotational viscometer, indicating that the terpolymer was perfectly synthesized and started to decompose at 350°C and showed good performance of fluid loss control up to 160°C. The ζ‐potential instrument and scanning electron microscopy were used to investigate the mechanisms of fluid loss control, indicating that the terpolymer can prevent the generation of flocculated structure in the cement and reduce the porosity of the filter cake. These results have important referential value for developing new high‐temperature‐resisting fluid loss agents. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers
Tensile properties of microbial β‐glucan films
Authors: Blahovec Jiří , Hejlová Anna , Čopíková Jana , Novák Miroslav
Published: October 2011

β‐glucan films with different plasticizer concentrations (glycerol and water) were deformed in tension and various mechanical characteristics (modulus of elasticity, yield stress, strength, and strain at rupture point) were evaluated. The influence of both plasticizers was of additive nature describable by the total plasticizer content. The influence is reflected by an exponential decrease of either modulus of elasticity or yield stress with increasing total plasticizer content. The film strength decreased linearly with plasticizer concentration, whereas the decline in strain at the rupture point followed a power function. It was also found that the stress parameters can be expressed via modulus of elasticity: the strength as linear function of the square root of the elasticity modulus and the yield stress as a linear function of the latter parameter. On the basis of such relations a quadratic function between strength and yield stress was proposed. This relation well describes the character of the deformation curves that were obtained at different deformation conditions. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Aging property of eco‐friendly anticorrosion organic coating film for telecommunication plant
Authors: Takeshita Yukitoshi , Jackson Richard A. , Sakata Seizou , Sawada Takashi , Nishio Ryuichi
Published: October 2011

Telecommunication facilities are protected against long‐term weather exposure by certain prevention technologies. One such technology, namely polymeric materials, is available for coating onto steel or galvanized steel. Physical and chemical aging is an important factor that affects the properties of polymer and, therefore, of coatings. The present study is focused on the effect of aging on the adhesive performance and rheological property of new eco‐friendly anticorrosion organic coating film that we are developing, which has a low volatile organic compound (VOC) content of less than 10%. Exposure to accelerated thermal cycling certainly had an influence on the coating film in that it degraded its adhesive strength and affected the storage modulus and loss tangent. E′ and tan δ were found to evaluate likely planes of failure in multilayer combinations of film. During aging at room temperature, the solvent might evaporate and reach equilibrium. A significant phenomenon was observed, namely that the strengthening effect might relate to the application of tensile stress before the complete evaporation of the solvent. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers
Liquid crystalline and photocrosslinkable poly(4,4′‐stilbeneoxy) alkylarylphosphates
Authors: Ravikrishnan Angayan , Sudhakara Posa , Kannan Palaninathan
Published: October 2011

Three series of liquid crystalline and photocrosslinkable poly(4,4′‐stilbeneoxy) alkylarylphosphates were synthesized from various 4,4′‐bis(m‐hydroxyalkyloxy)stilbenes (m = 2, 4, 6, 8, 10) and arylphosphorodichloridates in chloroform by solution polycondensation method. Polarized optical microscope (POM) and differential scanning calorimetry (DSC) observations revealed that polymers containing less than four methylene spacer groups did not exhibit liquid crystalline (LC) texture, possibly due to smaller microdomain and restricted movement of the mesogen. In contrast, polymers containing more than four methylene spacer group established LC texture, which has been attributed to the larger monodomain and free movement of mesogens. Thermogravimetric analysis (TGA) data indicated that thermal stability and char yield decreased with increasing flexible methylene spacer groups, increased significantly for biphenyloxy and 1‐naphthyloxy containing polymers than that of phenyloxy containing polymers ascribed to increasing aromaticity, size, and number of aromatic rings. Photocrosslinking of stilbene containing polymers has been shown to proceed via 2π‐2π cycloaddition reaction by Ultra‐violet (UV) and fluorescence. The rate photocrosslinking has been found to increase with increasing number of methylene group in the main chain. The aromaticity of the side chain also increases the rate of crosslinking. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers
Curing of epoxy/carbon nanotubes physical networks
Authors: Chapartegui Maialen , Markaide Nerea , Florez Sonia , Elizetxea Cristina , Fernandez Mercedes , Santamaria Anton
Published: October 2011

A melt‐mixing procedure has been used to disperse multi‐walled carbon nanotubes (MWCNT) in an epoxy matrix. According to dynamic viscoelastic results, a physical network is formed for carbon nanotube concentrations of 0.3 weight per cent (wt%) and above. The temperature activated curing process is followed analyzing the evolution of the dynamic viscoelastic functions and the dielectric loss with time. Curing process from a physical to a chemical network is monitored. The presence of MWCNT accelerates curing, even when the rheological percolation is not reached (absence of physical network). Several hypotheses are considered to explain this result. Electrical conductivity decreases during cure, so lower electrical conductivities are found for cured MWCNT/epoxy samples than for dispersions: this is explained by a distortion of nanotubes physical network and a reduction of the ionic conductivity contribution of the liquid phase. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers
Biaxial deformation and experimental study of PET at conditions applicable to stretch blow molding
Authors: Menary G.H. , Tan C.W. , Harkin‐Jones E.M.A. , Armstrong C.G. , Martin P.J.
Published: October 2011

This article is concerned with understanding the behavior of polyethylene terephthalate (PET) in the injection stretch blow molding (ISBM) process where it is typically biaxially stretched to form bottles for the packaging industry. A comprehensive experimental study was undertaken, analyzing the behavior of three different grades of PET under constant width (CW), simultaneous (EB), and sequential (SQ) equal biaxial deformation. Experiments were carried out at temperature and strain rate ranges of 80–110°C and 1 s−1 to 32 s−1, respectively, to different stretch ratios. Results show that the biaxial deformation behavior of PET exhibits a strong dependency on forming temperature, strain rate, stretch ratio, deformation mode, and molecular weight. The tests were also monitored via a high speed thermal image camera which showed an increase in temperature between 5°C and 15°C depending on the stretch conditions. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers
Synthesis and characterization of energetic GAP‐b‐PAEMA block copolymer
Authors: Zhang Yang , Zhao Juan , Yang Pan , He Shangjin , Huang Hengjian
Published: October 2011

Energetic block copolymer of polyglycidylazide‐b‐poly (azidoethyl methacrylate) (GAP‐b‐PAEMA) was synthesized and characterized. Macroinitiator PECH‐Br prepared via the reaction of 2‐bromoisobutyryl bromide with hydroxyl‐terminated polyepichlorohydrin (PECH‐OH) was used to initiate the atom transfer radical polymerization (ATRP) of chloroethyl methacrylate (CEMA). After azidation of the resulting copolymer, energetic copolymer GAP‐b‐PAEMA was obtained. Increase in the molecular weight determined by gel permeation chromatograph (GPC) is in agreement with the formation of block copolymer. Fourier transform infrared spectroscopy (FTIR) shows that the chlorine groups in the block copolymer can be substituted by azide group easily. Thermogravimetric analysis (TGA) shows that degradation of GAP‐b‐PAEMA involves two steps: the instantaneous decomposition of the azide groups followed by progressive scission of the polymer backbone. From differential scanning calorimetry (DSC) analysis, the GAP‐b‐PAEMA copolymer exhibits two glass transition temperatures (Tg) at −18 and 36°C, suggesting that the synthesized copolymer is a thermoplastic elastomer. This research provides a new method for the synthesis of energetic polymer. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Characterization of the spatial distribution of irradiance and spectrum in concentrating photovoltaic systems and their effect on multi‐junction solar cells
Authors: Victoria M. , Herrero R. , Domínguez C. , Antón I. , Askins S. , Sala G.
Published: October 2011

The irradiance and spectral distribution cast on the cell by a concentrating photovoltaic system, typically made up of a primary Fresnel lens and a secondary stage optical element, is dependent on many factors, and these distributions in turn influence the electrical performance of the cell. In this paper, the effect of spatial and spectral non‐uniform irradiance distribution on multi‐junction solar cell performance was analyzed using an integrated approach. Irradiance and spectral distributions were obtained by means of ray‐tracing simulation and by direct imaging at a range of cell‐to‐lens distances. At the same positions, I–V curves were measured and compared in order to evaluate non‐uniformity effects on cell performance. The procedure was applied to three different optical systems comprised a Fresnel lens with a secondary optical element consisting of either a pyramid, a dome, or a bare cell. Copyright © 2011 John Wiley & Sons, Ltd.
Unfurling of the band 4.1, ezrin, radixin, moesin (FERM) domain of the merlin tumor suppressor
Authors: Yogesha S. D. , Sharff Andrew J. , Giovannini Marco , Bricogne Gerard , Izard Tina
Published: October 2011

The merlin‐1 tumor suppressor is encoded by the Neurofibromatosis‐2 (Nf2) gene and loss‐of‐function Nf2 mutations lead to nervous system tumors in man and to several tumor types in mice. Merlin is an ERM (ezrin, radixin, moesin) family cytoskeletal protein that interacts with other ERM proteins and with components of cell–cell adherens junctions (AJs). Merlin stabilizes the links of AJs to the actin cytoskeleton. Thus, its loss destabilizes AJs, promoting cell migration and invasion, which in Nf2+/‐ mice leads to highly metastatic tumors. Paradoxically, the “closed” conformation of merlin‐1, where its N‐terminal four‐point‐one, ezrin, radixin, moesin (FERM) domain binds to its C‐terminal tail domain, directs its tumor suppressor functions. Here we report the crystal structure of the human merlin‐1 head domain when crystallized in the presence of its tail domain. Remarkably, unlike other ERM head–tail interactions, this structure suggests that binding of the tail provokes dimerization and dynamic movement and unfurling of the F2 motif of the FERM domain. We conclude the “closed” tumor suppressor conformer of merlin‐1 is in fact an “open” dimer whose functions are disabled by Nf2 mutations that disrupt this architecture.
Longer simulations sample larger subspaces of conformations while maintaining robust mechanisms of motion
Authors: Liu Lin , Gronenborn Angela M. , Bahar Ivet
Published: October 2011

Recent studies suggest that protein motions observed in molecular simulations are related to biochemical activities, although the computed time scales do not necessarily match those of the experimentally observed processes. The molecular origin of this conflicting observation is explored here for a test protein, cyanovirin‐N (CV‐N), through a series of molecular dynamics simulations that span a time range of three orders of magnitude up to 0.4 μs. Strikingly, increasing the simulation time leads to an approximately uniform amplification of the motional sizes, while maintaining the same conformational mechanics. Residue fluctuations exhibit amplitudes of 1–2 Å in the nanosecond simulations, whereas their average sizes increase by a factor of 4–5 in the microsecond regime. The mean‐square displacements averaged over all residues (y) exhibit a power law dependence of the form y ∝ x0.26 on the simulation time (x). Essential dynamics analysis of the trajectories, on the other hand, demonstrates that CV‐N has robust preferences to undergo specific types of motions that already can be detected at short simulation times, provided that multiple runs are performed and carefully analyzed. Proteins 2012. © 2011 Wiley Periodicals, Inc.
Electrically detected Rabi oscillations of phosphorus qubits in silicon
Authors: Morley Gavin W. , McCamey Dane R. , Boehme Christoph , van Tol Johan
Published: October 2011

Electrically detected magnetic resonance is a sensitive technique for studying electron spins bound to phosphorus atoms in silicon. Using a high magnetic field of 8.6 T increases this sensitivity by accessing a mechanism for spin‐to‐charge conversion which is different to that in the more commonly used magnetic field of ∼0.33 T. The higher‐field regime benefits from a long spin coherence time of over 100 µs because the phosphorus spins that are detected are not coupled to dangling‐bonds. Additionally, the high field permits the spin qubits to reach an equilibrium polarization of over 95% at a temperature of 2.8 K. We demonstrate electrically detected Rabi oscillations of these electron spins in the high‐field regime. The Rabi frequency is proportional to the square root of the excitation power as expected.
Effective Control Charts for Monitoring Multivariate Process Dispersion
Authors: Yen Chia‐Ling , Shiau Jyh‐Jen Horng , Yeh Arthur B.
Published: October 2011

When monitoring process dispersion, it is common to pay more attention to dispersion increases than to decreases for practical reasons. Nonetheless, it is also important to detect dispersion decreases for two reasons: (i) it deserves further investigations as to why the process has improved; and (ii) if the process has changed, the settings of the control chart would need to be adjusted for effective future monitoring. In this paper, we first propose an effective control chart for detecting multivariate dispersion decreases in phase II process monitoring, which is constructed using the same approach as that of the one‐sided likelihood‐ratio‐test‐based multivariate chart proposed recently in the literature for detecting dispersion increases. We then discuss a combined charting scheme by combining these two one‐sided charts for detecting either dispersion increases or decreases. Comparative simulation studies show that the proposed combined control charting scheme outperforms several existing two‐sided control charts in terms of the average run length when the process dispersion indeed increases or decreases. Two real‐life examples are presented to demonstrate the applicability of the proposed charts. Copyright © 2011 John Wiley & Sons, Ltd.
Optimal T2 Control Chart with a Double Sampling Scheme – An Alternative to the MEWMA Chart
Authors: Faraz Alireza , Heuchenne Cédric , Saniga Erwin
Published: October 2011

Recent studies have shown that a double sampling (DS) scheme yields improvements in detection times of process shifts over variable ratio sampling (VRS) methods that have been extensively studied in the literature. Additionally, a DS scheme is more practical than some of the VRS methods since the sampling interval is fixed. In this paper, we investigate the effect of double sampling on cost, a criterion as important as detection rate. We study economic statistical design of the DS T2 chart (ESD DS T2) so that designs are found that are economically optimal but yet meet desired statistical properties such as having low probabilities of false searches and high probabilities of rapid detection of process shifts. Through an illustrative example, we show that relatively large benefits can be achieved in a comparison with the classical T2 chart and the statistical DS T2 charts with our ESD DS T2 approach. Furthermore, the economic performance of the ESD DS T2 charts is favorably compared to the MEWMA and other VRS T2 control charts in the literature. Copyright © 2011 John Wiley & Sons, Ltd.
Solvation effect on the structural change of a globular protein: A molecular dynamics study
Authors: Mizukami Taku , Saito Hiroaki , Kawamoto Shuhei , Miyakawa Takeshi , Iwayama Masashi , Takasu Masako , Nagao Hidemi
Published: October 2011

To investigate the relationship between structural change and the solvation effect, we estimated the solvation free energy or excess chemical potential (ECP) of a globular protein by the energy representation method for the protein structure obtained by a molecular dynamic simulation. A large fluctuation of ECP was detected. The estimated ECP along the first principal component axis of protein fluctuation was accompanied with “open–close” structural change, which indicated a smooth and progressive change in ECP. By performing a global water density analysis in the grid space, the water density at the hydration site had a strong correlation with the ECP. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012
Photo‐SRM: laser‐induced dissociation improves detection selectivity of selected reaction monitoring mode
Authors: Enjalbert Quentin , Simon Romain , Salvador Arnaud , Antoine Rodolphe , Redon Sébastien , Ayhan Mehmet Menaf , Darbour Florence , Chambert Stéphane , Bretonnière Yann , Dugourd Philippe , Lemoine Jérôme
Published: October 2011

Selected Reaction Monitoring (SRM) carried out on triple‐quadrupole mass spectrometers coupled to liquid chromatography has been a reference method to develop quantitative analysis of small molecules in biological or environmental matrices for years and is currently emerging as a promising tool in clinical proteomic. However, sensitive assays in complex matrices are often hampered by the presence of co‐eluted compounds that share redundant transitions with the target species. On‐the‐fly better selection of the precursor ion by high‐field asymmetric waveform ion mobility spectrometry (FAIMS) or increased quadrupole resolution is one way to escape from interferences. In the present work we document the potential interest of substituting classical gas‐collision activation mode by laser‐induced dissociation in the visible wavelength range to improve the specificity of the fragmentation step. Optimization of the laser beam pathway across the different quadrupoles to ensure high photo‐dissociation yield in Q2 without detectable fragmentation in Q1 was assessed with sucrose tagged with a push‐pull chromophore. Next, the proof of concept that photo‐SRM ensures more specific detection than does conventional collision‐induced dissociation (CID)‐based SRM was carried out with oxytocin peptide. Oxytocin was derivatized by the thiol‐reactive QSY® 7 C5‐maleimide quencher on cysteine residues to shift its absorption property into the visible range. Photo‐SRM chromatograms of tagged oxytocin spiked in whole human plasma digest showed better detection specificity and sensitivity than CID, that resulted in extended calibration curve linearity. We anticipate that photo‐SRM might significantly improve the limit of quantification of classical SRM‐based assays targeting cysteine‐containing peptides. Copyright © 2011 John Wiley & Sons, Ltd.
Bioanalytical strategies for developing highly sensitive liquid chromatography/tandem mass spectrometry based methods for the peptide GLP‐1 agonists in support of discovery PK/PD studies
Authors: Zhang Hongwei , Xin Baomin , Caporuscio Christian , Olah Timothy V.
Published: October 2011

Highly sensitive liquid chromatography/tandem mass spectrometry (LC/MS/MS)‐based methods have been developed and implemented for the quantitative determination of a number of peptides under evaluation in our Glucagon‐Like Peptide‐1 (GLP‐1) discovery program for the treatment of diabetes. These peptides are GLP‐1 receptor agonists. Due to the high potency, low dose, and low exposure of these peptides, LC/MS/MS‐based methods with Lower Limits of Quantitation (LLOQs) (low picomolar range) were required to support discovery pharmacokinetic/ pharmacodynamic (PK/PD) studies. Compared with small molecules, many of these peptides posed significant bioanalytical challenges in the development of highly sensitive methods because of their parent signal splitting as a result of the formation of multiply charged states, the unfavorable fragmentation patterns for Selected Reaction Monitoring (SRM) transitions due to the generation of a large number of small mass product ions with relative low intensities, and adsorption issues observed during sample preparation. This paper details the strategies developed to maximize the sensitivity and improve LLOQs from aspects of mass spectrometry, chromatography, and sample preparation. A LLOQ of 10 picomolar was achieved for all of the investigated peptides using 100 μL of mouse plasma. This is a 100‐fold improvement on LLOQs over generic LC/MS/MS‐based methods when the same sample volume and the same mass spectrometer platform were used. The methods have been implemented in the support of discovery PK/PD studies. Copyright © 2011 John Wiley & Sons, Ltd.
The Burning Rate of Energetic Films of Nanostructured Porous Silicon
Authors: Plummer Andrew , Kuznetsov Valerian , Joyner Timothy , Shapter Joe , Voelcker Nicolas H.
Published: October 2011

A systematic study of nanoenergetic films consisting of nanostructured porous silicon impregnated with sodium perchlorate is carried out. The explosive properties of these films are investigated as a function of thickness, porosity, and confinement. The films' burning rates are investigated using fiber‐optic velocity probes, demonstrating that flame‐front velocities vary between approximately 1 and 500 m s−1 and are very sensitive to the films' structural characteristics. Analysis of the flame profile by high‐speed video is also presented, suggesting that the reaction type is a deflagration rather than a detonation. A strong plume of flame is emitted from the surface, indicating the potential for this material to perform useful work either as an initiator or as a propellant. The shape of the flame front transitioned from an inverted V at thin‐film thicknesses to a neat square‐shaped front once the material became self‐confining at 50 μm.
Controlled Synthesis of Tantalum Oxynitride and Nitride Nanoparticles
Authors: Gao Qingsheng , Giordano Cristina , Antonietti Markus
Published: October 2011

Synthesis of monodisperse metal nitride and oxynitride nanoparticles with a controllable chemical composition, size, and a well‐defined morphology are useful for applications in fields of catalysis, optoelectronics, and electrochemistry. In this paper a novel method for the controllable synthesis of highly crystalline tantalum oxynitride and nitride nanoparticles with a relatively low polydispersity is presented using urea as the nitrogen source. In the presence of calcium ions as assisting agents, by simply varying the initial urea/Ta molar ratio, both the composition and size of the final product can be tailored to switch from TaON to Ta3N5. The mechanism proposed is that Ca2+ slows down the release of NH3 from the decomposition of urea, which is indispensable for the controllable synthesis of oxynitride and nitride based nanoparticles.