bluuebunny/crossref_metadata_2025 huggingface dataset:
The prognostic value of changes in serum ferritin levels during therapy for hepatitis C virus infection
Authors: Ackerman Zvi , Pappo Orit , Ben‐Dov Iddo Z.
Published: May 2011

An increase in serum ferritin levels during combined interferon–ribavirin treatment in chronic patients infected with hepatitis C virus (HCV) can occur. A study was conducted to determine whether observing the kinetics of serum ferritin levels during antiviral therapy, may assist in predicting the rate of sustained virological response. The kinetics of serum ferritin levels during antiviral therapy in treatment‐naive, adherent patients with chronic HCV who had early virological response were characterized. Thirteen patients achieved sustained virological response (group 1) while eight patients did not (group 2). Pre‐treatment serum ferritin levels were higher in group 2 patients. During antiviral therapy, serum ferritin levels increased in both groups. On treatment, the median increase (compared to baseline) and the calculated rate of the increase in serum ferritin levels was higher in group 1 patients (874% vs. 272%, P < 0.05, 63%/week vs. 13%/week, P = 0.024, respectively). Red blood cell lysis did not contribute to the increase in serum ferritin level. Post‐treatment (1st month) serum ferritin levels in group 1 patients were lower than in group 2 patients. In addition, the degree of decline in the 1st month serum ferritin levels (from peak levels) in group 1 patients was higher (76% vs. 49%, P = 0.039). Measuring serum ferritin levels during antiviral therapy in HCV patients who had an early virological response may assist in predicting sustained virological response. J. Med. Virol. 83:1262–1268, 2011. © 2011 Wiley‐Liss, Inc.
The effects of widespread methadone treatment on the molecular epidemiology of hepatitis C virus infection among injection drug users in Hong Kong
Authors: Chan Denise P.C. , Lee Shui Shan , Lee Krystal C.K.
Published: May 2011

The distribution of HCV genotypes among injection drug users in Hong Kong was assessed in context of methadone treatment availability. Three time periods were defined by the year of initiating injection—on or before 1980, 1981–1994, and 1995–2006—with methadone becoming widely available since the second period. Of the 273 HCV RNA‐positive cases, the most prevalent subtype was HCV 6a (52.4%), followed by HCV 1b (38.5%). The new variants of HCV subtypes 6e and 6h were detected. Both subtypes 1b and 6a were prevalent among older injectors, while subtype 3a was more common in young injectors and those initiating injection recently during the third time period. Age (P < 0.05) and recent injection frequency (P < 0.01) were independently associated with HCV 6a infection. Subtype 1b was predominant in the first period, whereas 6a was more common in the second and third. Subtype 1b sequences appeared to have originated at two positions on the phylogenetic tree, while 6a showed a more disperse distribution suggestive of multiple introductions. Phylogenetic analysis on the NS5B region did not reveal specific clustering of any subtype/genotype. Overall, there was no suggestion of outbreaks of HCV. The extensive use of methadone may have protected Hong Kong from the emergence of HCV clusters among injection drug users. J. Med. Virol. 83:1187–1194, 2011. © 2011 Wiley‐Liss, Inc.
Rapid discrimination of oseltamivir‐resistant 275Y and ‐susceptible 275H substitutions in the neuraminidase gene of pandemic influenza A/H1N1 2009 virus by duplex one‐step RT‐PCR assay
Authors: Nakauchi Mina , Ujike Makoto , Obuchi Masatsugu , Takashita Emi , Takayama Ikuyo , Ejima Miho , Oba Kunihiro , Konomi Nami , Odagiri Takato , Tashiro Masato , Kageyama Tsutomu ,   the influenza virus surveillance group of Japan
Published: May 2011

Pandemic influenza A/H1N1 2009 (A/H1N1pdm) virus caused significant outbreaks worldwide last year (2009). A number of oseltamivir‐resistant A/H1N1pdm viruses possessing an H275Y substitution in the neuraminidase (NA) protein were reported sporadically in several countries, including Japan, but they were sensitive to zanamivir and did not spread in the community. In this study, to monitor rapidly and simply oseltamivir‐resistant A/H1N1pdm viruses possessing H275Y, a duplex one‐step RT‐PCR assay (H275Y RT‐PCR assay) was developed based on an endpoint genotyping analysis method. H275Y RT‐PCR assay evaluated using several subtypes/types of influenza A and B viruses and other respiratory pathogenic viruses and shown to have high sensitivity and high specificity. Forty‐four clinical specimens were tested after RNA purification using the H275Y RT‐PCR assay, resulting in one clinical specimen being found to contain a virus possessing the H275Y mutation. Seventy‐three clinical isolates were then tested with the H275Y assay by using clinical isolates in the cultured supernatants of cells directly, without RNA purification, and the results were consistent with the NA sequencing. Since the H275Y RT‐PCR assay could detect the H275Y mutation in clinical isolates without RNA purification, as well as a H275Y mutated virus in clinical specimens after RNA purification, the assay was considered a powerful tool for surveillance screening of oseltamivir‐resistant A/H1N1pdm virus activity. J. Med. Virol. 83:1121–1127, 2011. © 2011 Wiley‐Liss, Inc.
A physically based, accurate compact model of direct tunneling gate current considering quantum mechanical effects in nanoscale metal‐oxide‐semiconductor field‐effect transistors
Authors: Karim M. A. , Khosru Q. D. M.
Published: May 2011

We present a physically based, accurate model of the direct tunneling gate current of nanoscale metal‐oxide‐semiconductor field‐effect transistors considering quantum mechanical effects. Effect of wave function penetration into the gate dielectric is also incorporated. When electrons tunnel from the metal oxide semiconductor inversion layer to the gate, the eigenenergies of the quasi‐bound states turn out to be complex quantities. The imaginary part of these complex eigenenergies, Γij, are required to estimate the finite lifetimes of these states. We present an empirical equation of Γij as a function of surface potential. Inversion layer electron concentration is determined using eigenenergies, calculated by modified Airy function approximation. Hence, a compact model of direct tunneling gate current is proposed using a novel approach. Good agreement of the proposed compact model with self‐consistent numerical simulator and published experimental data for a wide range of substrate doping densities and oxide thicknesses states the accuracy and robustness of the proposed model. The proposed model can well be extended for devices with high‐κ/stack gate dielectrics introducing necessary modifications. Copyright © 2011 John Wiley & Sons, Ltd.
Muscle and joint‐contact loading at the glenohumeral joint after reverse total shoulder arthroplasty
Authors: Ackland David C. , Roshan‐Zamir Sasha , Richardson Martin , Pandy Marcus G.
Published: May 2011

The purposes of this study were to determine the contributions of each shoulder muscle to glenohumeral joint force during abduction and flexion in both the anatomical and post‐operative shoulder and to identify factors that may contribute to the incidence of glenoid component loosening/failure and joint instability in the shoulder after reverse shoulder arthroplasty (RSA). Eight cadaveric upper extremities were mounted onto a testing apparatus. Muscle lines of action were measured, and muscle forces and muscle contributions to glenohumeral joint forces were determined during abduction and flexion of the pre‐operative anatomical shoulder and of the shoulder after arthroplasty. Muscle forces in the middle deltoid during abduction and those in the middle and anterior deltoid during flexion were significantly lower in the reverse shoulder than the pre‐operative shoulder (p < 0.017). The resultant glenohumeral joint force in the reverse shoulder was significantly lower than that in the pre‐operative shoulder; however, the superior shear force acting at the glenohumeral joint was significantly higher (p < 0.001). Reverse total shoulder arthroplasty reduces muscle effort in performing lifting and pushing tasks; however, reduced joint compressive force has the potential to compromise joint stability, while an increased superior joint shear force may contribute to component loosening/failure. Because greater superior shear force is generated in flexion than in abduction, care should be taken to avoid excessive shoulder loading in this plane of elevation. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29:1850–1858, 2011
The dimensionality of posttraumatic stress symptoms and their relationship to depression in children and adolescents
Authors: Hukkelberg Silje S. , Jensen Tine K.
Published: May 2011

The aims of the study were twofold: to investigate 6 different factor structures in posttraumatic stress symptoms using confirmatory factor analyses with polychoric correlations, and to examine to what extent posttraumatic stress disorder (PTSD) is different from depression. The study was based on a clinical sample of 312 children and adolescents 10 to 18 years old who had experienced different types of traumatic events. Results showed that 3 out of the 6 models demonstrated good fit, but the dysphoria model provided the best fit to the data. Furthermore, correlations between depression and subscales of the dysphoria and numbing models provided additional support for the dysphoria model.
Rape, sex partnership, and substance use consequences in women veterans
Authors: Booth Brenda M. , Mengeling Michelle , Torner James , Sadler Anne G.
Published: May 2011

The association of rape history and sexual partnership with alcohol and drug use consequences in women veterans is unknown. Midwestern women veterans (N = 1,004) completed a retrospective telephone interview assessing demographics, rape history, substance abuse and dependence, depression, and posttraumatic stress disorder (PTSD). One third met lifetime criteria for substance use disorder (SUD), half reported lifetime completed rape, a third childhood rape, one quarter in‐military rape, 11% sex with women. Lifetime SUD was higher for women with rape history (64% vs. 44%). Women with women as sex partners had significantly higher rates of all measures of rape, and also lifetime substance use disorder. Postmilitary rape, sex partnership, and current depression were significantly associated with lifetime SUD in multivariate models (odds ratio = 2.3, 3.6, 2.1, respectively). Many women veterans have a high need for comprehensive mental health services.
Immobilization of Peroxidase on SiO2 Surfaces with the Help of a Dendronized Polymer and the Avidin‐Biotin System
Authors: Fornera Sara , Balmer Tobias E. , Zhang Baozhong , Schlüter A. Dieter , Walde Peter
Published: May 2011

Horseradish peroxidase (HRP) is immobilized in three easy steps on SiO2 surfaces with the help of a polycationic second generation dendronized polymer (denpol) and the biotin‐avidin system. This stepwise immobilization process is monitored and quantitatively analyzed with the transmission interferometric adsorption sensor. Partially biotinylated denpol is first adsorbed onto SiO2, followed by addition of avidin and then of biotinylated HRP. Denpols in their molecular structure combine properties of polymers as well as dendrimers which are found to be of clear advantage for this type of non‐covalent enzyme immobilization. With respect to the reproducibility of the adsorption process and with respect to the stability of the adsorbed polymer layer, the denpol is superior to α‐poly‐D‐lysine which is used as a reference polymer. Furthermore, HRP immobilized with the denpol on commercial glass slides remains considerably more active upon storage as compared to HRP immobilized with the help of α‐poly‐D‐lysine with a similar number of repeating units. The ease of the denpol‐mediated HRP immobilization and the high stability of the immobilized enzyme are promising for bioanalytical applications.

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Iron‐mediated AGET ATRP of Methyl Methacrylate in the Presence of Catalytic Amounts of Base
Authors: He Wenjing , Zhang Lifen , Bai Liangjiu , Zhang Zhengbiao , Zhu Jian , Cheng Zhenping , Zhu Xiulin
Published: May 2011

A novel method for iron‐mediated atom transfer radical polymerization with activators generated by electron transfer (AGET) ATRP of a polar monomer, methyl methacrylate (MMA), is developed in the presence of catalytic amounts of inorganic base NaHCO3 or Na2CO3. The polymerization is carried out using FeCl3 · 6H2O as the catalyst, triphenylphosphine as the ligand, ethyl 2‐bromoisobutyrate as the initiator, and vitamin C as the reducing agent at 70 °C. It is found that the addition of base into the polymerization system enhances the polymerization rate significantly but does not destroy the controllability over the molecular weight and molar‐mass dispersity.

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Microwave‐Induced Shape‐Memory Effect of Chemically Crosslinked Moist Poly(vinyl alcohol) Networks
Authors: Du Haiyan , Yu Yunlong , Jiang Guangming , Zhang Junhua , Bao JianJun
Published: May 2011

MWs are explored as the driving force for an SMP based on chemically crosslinked moist PVA networks. The samples show rapid shape recovery under MW irradiation, whereas dry samples experience no shape changes when irradiated. This effect is attributed to the heat created by vibrating water molecules inside the samples that supplies the energy required for shape recovery. The rate of recovery rate is affected not only by the water content in the material but also by the applied MW power output. Automatic network analysis, DSC, and DMA are used to study the dielectric, thermal and mechanical properties of the samples. MW‐induced shape recovery offers advantages such as high and variable recovery rate and the absence of direct contact between the heating source and the material.

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Effect of Co‐Rotation and Counter‐Rotation Extrusion Processing on the Thermal and Mechanical Properties, and Morphology of Plasticized Soy Protein Isolate and Poly(butylene succinate) Blends
Authors: Bonham Sara , Misra Manjusri , Mohanty Amar K.
Published: May 2011

Blends of plasticized soy protein isolate (PSPI) and poly(butylenes succinate) (PBS) were prepared in a 70:30 wt.‐% ratio via co‐rotation (CR) and counter‐rotation (CTR) twin‐screw extrusion. The novelty in this research suggests that CTR extrusion provides enhanced interfacial adhesion, tensile elongation and prolonged onset (Tonset) and end (Tend) thermal degradation temperatures. The average tensile strain at break showed to be ≈40% higher for PSPI‐CTR material and ≈55% higher for PBS:PSPI‐CTR (70:30) blends. Both Tonset and Tend for CTR processed PBS:PSPI(70:30) and PSPI were ≈10 °C greater than those of CR. These results suggest that the enhanced shear rate and radial motion associated with CTR allows for better destructurization and blending of PSPI within the PBS matrix, resulting in enhanced structural integrity due to the formation of possible amide and ester linkages. Scanning electron microscopy (SEM) provides further support based on evidence of reduced voids on the surface of all CTR blends

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Prostasomal DNA characterization and transfer into human sperm
Authors: Ronquist Göran K. , Larsson Anders , Ronquist Gunnar , Isaksson Anders , Hreinsson Julius , Carlsson Lena , Stavreus‐Evers Anneli
Published: May 2011

Human prostasomes, exosome‐like microvesicles secreted by acinar cells of the prostate gland, contain chromosomal DNA. Agarose gel electrophoresis of DNA from seminal prostasomes displayed fragments of over 12 kb and smaller, with a distinct band around 1 kb that was excised, cloned, and sequenced. The sequences showed 8 out of 25 clones (32%) originating from genes. We elaborated the concept further by carrying out a genome‐wide DNA copy number analysis of prostasomal DNA, hypothesizing that human prostasomes contain fragments of DNA randomly selected from the entire genome. Acridine orange‐stained prostasomes were incubated with freshly prepared sperm for different times, and a transfer of acridine orange‐stained prostasomal DNA to sperm (preferentially the head region) was observed. Fluorescence microscopy of slices in the center of 14 optical slides of the sperm head displayed an even fluorescence rather than a halo‐like one, indicating DNA‐uptake rather than just binding along the sperm head membrane. Mol. Reprod. Dev. 78:467–476, 2011. © 2011 Wiley‐Liss, Inc.
On the anatomy and histology of the pubovisceral muscle enthesis in women
Authors: Kim Jinyong , Ramanah Rajeev , DeLancey John O.L. , Ashton‐Miller James A.
Published: May 2011

Aims

The origin of the pubovisceral muscle (PVM) from the pubic bone is known to be at elevated risk for injury during difficult vaginal births. We examined the anatomy and histology of its enthesial origin to classify its type and see if it differs from appendicular entheses.

Methods

Parasagittal sections of the pubic bone, PVM enthesis, myotendinous junction, and muscle proper were harvested from five female cadavers (51–98 years). Histological sections were prepared with hematoxylin and eosin, Masson's trichrome, and Verhoeff‐Van Gieson stains. The type of enthesis was identified according to a published enthesial classification scheme. Quantitative imaging analysis was performed in sampling bands 2 mm apart along the enthesis to determine its cross‐sectional area and composition.

Results

The PVM enthesis can be classified as a fibrous enthesis. The PVM muscle fibers terminated in collagenous fibers that insert tangentially onto the periosteum of the pubic bone for the most part. Sharpey's fibers were not observed. In a longitudinal cross‐section, the area of the connective tissue and muscle becomes equal approximately 8 mm from the pubic bone.

Conclusion

The PVM originates bilaterally from the pubic bone via fibrous entheses whose collagen fibers arise tangentially from the periosteum of the pubic bone. Neurourol. Urodynam. 30:1366–1370, 2011. © 2010 Wiley‐Liss, Inc.
On the perturbation of the Q‐factor of the QR factorization
Authors: Chang X.‐W.
Published: May 2011

This paper gives normwise and componentwise perturbation analyses for the Q‐factor of the QR factorization of the matrix A with full column rank when A suffers from an additive perturbation. Rigorous perturbation bounds are derived on the projections of the perturbation of the Q‐factor in the range of A and its orthogonal complement. These bounds overcome a serious shortcoming of the first‐order perturbation bounds in the literature and can be used safely. From these bounds, identical or equivalent first‐order perturbation bounds in the literature can easily be derived. When A is square and nonsingular, tighter and simpler rigorous perturbation bounds on the perturbation of the Q‐factor are presented. Copyright © 2011 John Wiley & Sons, Ltd.
Cyanate ester–alumina nanoparticle suspensions: Effect of alumina concentration on viscosity and cure behavior
Authors: Ament Katherine A. , Kessler Michael R. , Akinc Mufit
Published: May 2011

The effect of alumina nanoparticles on the viscosity and curing behavior of a bisphenol E cyanate ester monomer suspension was investigated by rheometry and differential scanning calorimetry. The viscosity was found to increase with solids content and was fit well by the Mooney equation. Cure experiments indicate that alumina particles catalyze the curing of the suspensions. The viscosity reduction achieved at high particle loadings by the addition of benzoic acid was also investigated by nuclear magnetic resonance. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
A new insight into the mechanism of influence of different inorganic salts on optical properties of water‐soluble cationic conjugated polymers
Authors: Liu Qianqian , Lü Xiaodan , Geng Lei , Lü Changli
Published: May 2011

The water‐soluble conjugated polyelectrolyte poly{2,5‐bis[3‐(N,N,N‐triethylammoniumbromide)‐1‐oxapropyl]‐1,4‐phenylenevinylene} (P2) was synthesized and the influences of different inorganic salts on the optical properties of the polyelectrolyte were studied. New absorption and emission peaks at longer wavelength can be observed in the case of P2 with addition of different concentrations of Cl− or NO3−, whereas addition of I− or ClO4− only induces a red shift. Interestingly, addition of SO42− or F− does not result in considerable changes in optical spectra. Through UV‐visible spectrometry, photoluminescence, 1H NMR and cyclic voltammetry, we showed that the nature of the inorganic salts brings these different changes. The special structure of the $\prod{_{4}}^{6}$ bond of NO3− and the large electronegativity of chlorine lead to an electron transfer between the conjugated polymer and the negative ions. The large radius of I− and the weak electron withdrawing ability of ClO4− only bring a red shift of optical spectra. In addition, SO42− and F− do not affect the spectra significantly, except that the fluorescence intensity falls slightly indicating that P2 is not sensitive to these ions. Copyright © 2011 Society of Chemical Industry
Perceptions of declining classmate and teacher support following the transition to high school: Potential correlates of increasing student mental health difficulties
Authors: Wit David J. De , Karioja Kim , Rye B. J. , Shain Martin
Published: May 2011

Emotional support from classmates and teachers is a powerful protective factor in averting or reducing student mental health problems. Yet, longitudinal evidence indicates that there is decreased support from these groups as students advance to higher grade levels, a change that may be linked to diminishing mental health. This study followed 2,616 students from 23 high schools to test the hypothesis that perceptions of declining classmate and teacher support are associated with declining mental health. Growth curve analysis revealed significant decreases in support and self‐esteem and increases in symptoms of depression and social anxiety. Boys demonstrated steeper declines than girls in classmate support and self‐esteem and sharper increases in depression. As hypothesized, declining classmate and teacher support was associated with worsening self‐esteem and depression. Only declines in classmate support were associated with increases in social anxiety. Results were similar across gender categories. Implications for school‐based practices targeting social support are discussed. © 2011 Wiley Periodicals, Inc.
Surface‐Grafted conjugated polymers for hybrid cellulose materials
Authors: Peterson Joseph J. , Willgert Markus , Hansson Susanne , Malmström Eva , Carter Kenneth R.
Published: May 2011

Conjugated polymers were grafted onto cellulose substrates in an effort to create a general method for the synthesis of conjugated polymer/cellulose hybrid materials. In this report, we describe the grafting of poly(fluorene), poly(fluorenevinylene), and a poly(fluorene‐ethynylene‐phenylene) onto modified cellulose paper substrates using Suzuki, Heck, and Sonogashira‐type polymerizations, respectively. The application of these three widely used coupling chemistries to surface‐grafted conjugated polymers on cellulose provides a general route to cellulose‐based hybrid materials tunable with almost any aromatic repeat structure for specific applications. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Alternating narrow band gap copolymers derived from indeno[1,2‐b]fluorene and thiophene‐cored‐thieno[3,4‐b]pyrazine derivatives—Synthesis, characterization and comparative studies of photochemical stability
Authors: Xia Yangjun , Tong Junfeng , Li Bin , Wang Chenglong , Liu Hongzhong
Published: May 2011

Alternating narrow band gap (NBG) conjugated polymers derived from 6,6′,12,12′‐tetraoctylindeno[1,2‐b]fluorene (IF) and 2,3‐dimethyl‐5,7‐dithien‐2‐yl‐thieno[3,4‐b]pyrazine (DTTP), 2,3‐diphenyl‐5,7‐dithien‐2‐yl‐thieno[3,4‐b]pyrazine (DPTP) or 2,3‐dioctyl‐5,7‐dithien‐2‐yl‐thieno[3,4‐b]pyrazine (DOTP), named as PIF‐DTTP, PIF‐DPTP, and PIF‐DOTP, respectively, were synthesized by Suzuki coupling reaction and characterized. The photochemical stabilities of the copolymers and copolymer derived from IF and 5,7‐dithien‐2‐yl‐thieno[3,4‐b]pyrazine (DTP) were investigated by the UV absorptions, PL spectra, FT‐IR spectra, and photovoltaic properties of the copolymers as a function of UV irradiation time. The studies revealed that the degradation of thieno[3,4‐b]pyrazine (TP) ring under UV irradiation can be retarded or eliminated by introducing phenyl group into the 2,3‐positions of TP ring, and indicated that 2,3‐diphenylthieno[3,4‐b]pyrazine could be used as durable electron deficient moiety to achieve donor–acceptor NBG‐conjugated polymers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Synthesis of low grafting density molecular brush from a poly(N‐alkyl urea peptoid) backbone
Authors: Chen Xiaoping , Ayres Neil
Published: May 2011

The synthesis of a molecular brush was accomplished by combining step‐growth polymerization and reversible addition fragmentation chain transfer (RAFT) polymerization in a “grafting from” methodology. A symmetrical N‐alkyl urea peptoid sixmer containing alkyne functional groups was prepared using a divergent strategy, and the structure of the product was confirmed using NMR spectroscopy and mass spectrometry. A step‐growth process was used to prepare a linear poly(N‐alkyl urea peptoid) by reacting the diamine‐functionalized N‐alkyl urea peptoid sixmer with a diisocyanate. RAFT chain transfer agents were coupled to the poly(N‐alkyl urea peptoid) backbone through a copper‐catalyzed azide/alkyne cycloaddition reaction. The afforded macro‐RAFT agent was used to sequentially polymerize styrene and tert‐butyl acrylate block copolymer arms from the poly(N‐alkyl urea peptoid) backbone. The tert‐butyl groups were removed using dilute trifluoroacetic acid affording hydrophilic polyacrylic acid segments. The molecular brushes were observed to generate micelles in aqueous solution. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Poly[(sodium sulfamate/carboxylate)isoprene‐b‐2‐vinyl pyridine] block polyampholytes: Synthesis and self‐assembly in aqueous media
Authors: Mantzaridis Christos , Pispas Stergios
Published: May 2011

We report on the synthesis of poly[(sodium sulfamate/carboxylate) isoprene‐b‐2‐vinyl pyridine] block polyampholytes (SCPI‐P2VP), utilizing anionic polymerization and post polymerization functionalization reactions. The precursor poly(isoprene‐b‐(2‐vinylpyridine)) diblock copolymers (PI‐P2VP), containing a polyisoprene (PI) block with high 1,4 microstructure, were prepared by anionic polymerization high vacuum techniques, in two steps, involving change of the polymerization solvent. Subsequent functionalization of the PI block with chlorosulfonyl isocyanate, introduced sulfamate and carboxylate groups in the polymer chains and produced the desired block polyampholytes. The successful synthesis of the polyampolytes was corroborated by elemental analysis and IR spectroscopy measurements. The self‐assembly behaviour of the aforementioned polyampholytes was studied in aqueous solutions as a function of pH, by aid of dynamic and static light scattering, zeta potential, fluorescence spectroscopy and atomic force microscopy. Experimental results indicate that the block polyampholytes form micellar structures with P2VP cores and SCPI coronas at pH > 6, whereas more compact nanoparticles are formed at pH < 4 from the complexation of positively charged P2VP and SCPI, stabilized by excess negative charges of uncomplexed SCI segments. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Separation of single‐walled carbon nanotubes with aromatic group functionalized polymethacrylates and building blocks contribution to the enrichment
Authors: Pan Xiaoyong , Chan‐Park Mary B.
Published: May 2011

We previously showed that in N,N‐dimethylformamide (DMF), poly(9‐anthracenylmethyl methacrylate) (PAMMA) and poly(2‐naphthylmethacrylate) selectively disperse semiconducting and metallic single‐walled carbon nanotubes (SWNTs), respectively. We have also proposed a new noncovalent polymer interaction based on photon induced dipole–dipole interaction to account for the metallicity‐based selectivity. In this article, we investigate two other polymethacrylates, that is, poly(benzyl methacrylate) (PBMA) and poly(methylmethacrylate)‐co‐(9‐anthracenylmethyl acrylate) (PMMA‐c‐PAMA) in the light of our previously proposed photon‐induced dipole–dipole interaction. We find that PBMA and PMM‐c‐PAMMA in DMF show no metallicity selectivity. The different selective behavior of the four polymers in DMF manifests the decisive influence of the side aromatic group in determining their metallicity selectivity. The nonpreferential energy transfer from PMMA‐c‐PAMA to SWNTs and the nonoverlap of PBMA fluorescence (in the ultraviolet range) with nanotube absorption account for their nonselectivity of specific nanotube species. Further, the parallel relationship between the diameters of extracted tube species and the affinity between polymers and solvents suggests the leading role of the polymeric conformation on the diameter selectivity. A sufficient (i.e., 2 weeks) standing time of the SWNTs solution after sonication, during which the polymers presumably optimize their conformation to the SWNTs, was found to be essential to the enrichment. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011
Interactions in a blend of two polymers greatly differing in glass transition temperature
Authors: Kratochvíl Jaroslav , Šturcová Adriana , Sikora Antonín , Dybal Jiří
Published: May 2011

Blends of poly(N‐methyldodecano‐12‐lactam) PMDL with poly(4‐vinyphenol) PVPh have been studied by the DSC and ATR FTIR methods. The difference in glass transition temperature Tg between the components is 206 °C. A single composition‐dependent Tg suggests miscibility of the system, that is, homogeneity on the scale of about 10 nm. Fitting of the equation of Brostow et al. to the Tg data indicates relatively strong specific interactions and high complexity of the system. The Schneider's equation applied separately to low‐ and high‐PVPh regions provides good agreement with experiment; the calculated curves cross at the point of PVPh weight fraction 0.27. In the low‐PVPh region, the analysis indicates weak interactions with predominance of segment homocontacts and strong involvement of conformational entropy. In the high‐PVPh region, strong specific interactions predominate and entropic effects are suppressed. Composition dependences of the heat capacity difference at Tg and the width of glass transition indicate strong interactions in the system and existence of certain heterogeneities on segmental level, respectively. According to ATR FTIR, hydrogen bonds between PVPh as proton donor and PMDL as proton acceptor induce miscibility in blends of higher PVPh content (above about 0.28 weight fraction). In low‐PVPh blends, it is conformational entropy that enables intimate intermolecular mixing. Hydrogen bonds adopt several (distorted) geometries and are on average stronger than average hydrogen bonds formed in self‐associating PVPh. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011
Characterization and Tribological Behaviour of Siloxane‐based Plasma Coatings on HNBR Rubber
Authors: Verheyde Bert , Havermans Danny , Vanhulsel Annick
Published: May 2011

A cold atmospheric pressure plasma jet (PlasmaSpot) was developed in our department and was successfully used to deposit siloxane‐based coatings on elastomer materials for tribological improvement. This paper reports on the deposition of a low‐friction atmospheric plasma coating on an HNBR sample using (3‐aminopropyl)triethoxysilane (APEO) as precursor. The chemical structure of the coating was examined with XPS and FTIR spectroscopy. Monitoring the top surface of the coating by optical microscopy showed 2–3 µm wide cracks appearing in the coating some days after deposition. Furthermore, a migration of waxes was seen from the bulk rubber through the cracks. The chemical nature of these products was revealed by FTIR analysis. Although these waxes act as lubricant and are added to the rubber for better processability, a tribological evaluation in a ball‐on‐disc test rig revealed that they did not contribute to the lower friction coefficient. A significant decrease of the friction coefficient was measured for the plasma coated HNBR sample compared to the untreated HNBR sample.

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A Century (1910–2008) of Change in a Collapsing Pingo, Parry Peninsula, Western Arctic Coast, Canada
Authors: Mackay J. R. , Burn C. R.
Published: May 2011

An isolated, eroding pingo at the southern end of Parry Peninsula, N.W.T., Canada was first photographed in about 1910. The photograph allows examination of a century of landform change. Since 1910, the pingo crater pond has drained, the north side of the pingo has become well vegetated, the serrated crest has been smoothed, and the lake bottom has become colonised by willows and other vegetation. The height of the feature was over 100 ft (30 m) in 1910 and is now about 50 ft (15–17 m). The erosion of the pingo has probably been dominated by the strong southerly katabatic winds in the area, as the vegetation on the south side of the pingo is poorly developed in comparison with the north side. A secondary cause of erosion has been the numerous excavations by ground squirrels (Spermophilus parryii) and foxes (Vulpes lagopus) on the slopes of the pingo. It is unusual to detect change of collapsed pingos near the western Arctic coast of Canada unless ground ice is exposed in the core or on the sides of the pingo. The increases since 1996 in height and cover of willows are the first record of such change from western Arctic Canada. Copyright © 2011 John Wiley & Sons, Ltd.
Pedotransfer functions for isoproturon sorption on soils and vadose zone materials
Authors: Moeys Julien , Bergheaud Valérie , Coquet Yves
Published: May 2011

BACKGROUND: Sorption coefficients (the linear KD or the non‐linear KF and NF) are critical parameters in models of pesticide transport to groundwater or surface water. In this work, a dataset of isoproturon sorption coefficients and corresponding soil properties (264 KD and 55 KF) was compiled, and pedotransfer functions were built for predicting isoproturon sorption in soils and vadose zone materials. These were benchmarked against various other prediction methods.

RESULTS: The results show that the organic carbon content (OC) and pH are the two main soil properties influencing isoproturon KD. The pedotransfer function is KD = 1.7822 + 0.0162 OC1.5 − 0.1958 pH (KD in L kg−1 and OC in g kg−1). For low‐OC soils (OC < 6.15 g kg−1), clay and pH are most influential. The pedotransfer function is then KD = 0.9980 + 0.0002 clay − 0.0990 pH (clay in g kg−1). Benchmarking KD estimations showed that functions calibrated on more specific subsets of the data perform better on these subsets than functions calibrated on larger subsets.

CONCLUSION: Predicting isoproturon sorption in soils in unsampled locations should rely, whenever possible, and by order of preference, on (a) site‐ or soil‐specific pedotransfer functions, (b) pedotransfer functions calibrated on a large dataset, (c) KOC values calculated on a large dataset or (d) KOC values taken from existing pesticide properties databases. Copyright © 2011 Society of Chemical Industry
Translocation and degradation of pyrazosulfuron‐ethyl in rice soil
Authors: Singh Neera , Singh Shashi B
Published: May 2011

BACKGROUND: Pyrazosulfuron‐ethyl {ethyl 5‐[(4,6‐dimethoxypyrimidin‐2‐ylcarbamoyl)‐sulfamoyl]‐1‐methylpyrazole‐4‐carboxylate} is a new rice herbicide belonging to the sulfonylurea group. This study reports the translocation of 14C‐pyrazosulfuron‐ethyl to rice plants and its degradation in rice‐planted and unplanted soil.

RESULTS: Pyrazosulfuron‐ethyl did not show any appreciable translocation to rice shoots, as 14C‐activity translocated to the aerial portion never exceeded 1% of the initially applied 14C‐activity over a 25 day period. Results suggested that the dissipation of pyrazosulfuron‐ethyl from soils followed first‐order kinetics with a half‐life of 5.5 and 6.9 days in rice‐planted and unplanted soils respectively. HPLC analysis of the organic extract of soil samples showed the formation of three metabolites, namely ethyl 5‐(aminosulfonyl)‐1‐methyl‐1‐H‐pyrazole‐4‐carboxylate, 5‐[({[(4,6‐dimethoxy‐2 pyrimidinyl)‐amino]‐carbonyl} amino)‐sulfonyl]‐1‐methyl‐1H‐pyrazole‐4‐carboxylic acid and 2‐amino‐4,6‐dimethoxy pyrimidine, in both rice‐planted and unplanted soils.

CONCLUSION: The study indicates that pyrazosulfuron‐ethyl was a short‐lived compound in the soil and was degraded relatively faster in rice‐planted soil than in unplanted soil. The herbicide did not show any appreciable translocation to rice plants. Copyright © 2011 Society of Chemical Industry
Anthocyanin‐rich Fractions of Blackberry Extracts Reduce UV‐induced Free Radicals and Oxidative Damage in Keratinocytes
Authors: Murapa Patience , Dai Jin , Chung Michael , Mumper Russell J. , D'Orazio John
Published: May 2011

Hull blackberries were purified using solid phase extraction to obtain anthocyanin‐rich methanol fractions. This method concentrated phenolics and anthocyanins, recovering 97% and 76% of the total yield in puree or powder extracts, respectively, which represented a 24–63 fold increase of the total antioxidant capacity when compared with either the water fraction or the original extract. The ability of these fractions to protect primary keratinocytes against UV‐induced oxidative damage was assessed. Anthocyanin‐rich methanol fractions derived from either blackberry powder or puree exhibited strong antioxidant properties, protecting against UV‐induced ROS nearly as efficiently as N‐acetyl cysteine. Furthermore, the fractions up‐regulated the expression of catalase, MnSOD, Gpx1/2 and Gsta1 antioxidant enzymes. Thus, it is concluded that blackberry extracts may protect keratinocytes against UV‐mediated oxidative damage. Copyright © 2011 John Wiley & Sons, Ltd.
An Aqueous Extract of Withania somnifera Root Inhibits Amyloid β Fibril Formation In Vitro
Authors: Kumar Suresh , Harris Robin J. , Seal Christopher J. , Okello Edward J.
Published: May 2011

The ability of an aqueous extract of W. somnifera L. Dunal (Family: Solanaceae) roots to inhibit fibril formation by the amyloid‐β peptide in vitro was investigated. W. somnifera is used extensively in traditional Ayurvedic medicine as a nerve tonic with reputed memory enhancing properties. Inhibition of fibrillogenesis measured by transmission electron microscopy and ThT fluorescence assay showed that an aqueous extract of W. somnifera strongly inhibited Aβ fibril formation in a concentration‐dependent manner, when compared with control samples. These results suggest that the aqueous extract of W. somnifera root has an ability to inhibit the formation of mature amyloid‐β fibrils in vitro, which are known to lead to amyloid plaque formation in vivo. Copyright © 2011 John Wiley & Sons, Ltd.
Combined Treatment of Curcumin and Small Molecule Inhibitors Suppresses Proliferation of A549 and H1299 Human Non‐Small‐Cell Lung Cancer Cells
Authors: Lin Hui‐Ping , Kuo Li‐Kuo , Chuu Chih‐Pin
Published: May 2011

Curcumin (diferuloylmethane) is a phenolic compound present in turmeric and is ingested daily in many parts of the world. Curcumin has been reported to cause inhibition on proliferation and induction of apoptosis in many human cancer cell lines, including non‐small cell lung cancer cells (NSCLC). However, the clinical application of curcumin is restricted by its low bioavailability. In this report, it was observed that combined treatment of a low dosage of curcumin (5–10 µ m) with a low concentration (0.1–2.5 µ m) of small molecule inhibitors, including AG1478, AG1024, PD173074, LY294002 and caffeic acid phenethyl ester (CAPE) increased the growth inhibition in two human NSCLC cell lines: A549 and H1299 cells. The observation suggested that combined treatment of a low dosage of curcumin with inhibitors against epidermal growth factor receptor (EGFR), insulin‐like growth factor 1 (IGF‐1R), fibroblast growth factors receptor (FGFR), phosphatidylinositol 3‐kinases (PI3K) or NF‐κB signaling pathway may be a potential adjuvant therapy beneficial to NSCLC patients. Copyright © 2011 John Wiley & Sons, Ltd.
Extensive studies of large‐amplitude Kelvin–Helmholtz billows in the lower atmosphere with VHF middle and upper atmosphere radar
Authors: Fukao Shoichiro , Luce Hubert , Mega Tomoaki , Yamamoto Masayuki K.
Published: May 2011

In the present work, characteristics of large‐amplitude (>150 m) Kelvin–Helmholtz (KH) billows in the lower atmosphere are analysed, with emphasis on the turbulent properties. First, past studies are reviewed. Almost all the studies reported gradient Richardson number (Ri) close to 0.25. Results of observations in the height range 1.32–20.34 km using 46.5 MHz middle and upper atmosphere radar (MUR; Japan, 34.85°N, 136.10°E) are then described. A total of ∼600 h of data at high vertical and range resolutions was used. Except for very few cases, trains of KH braids are not followed by layer splitting, which can eventually result from turbulent mixing. A particular event shows some sort of turbulent plumes at the interface between a nearly neutral layer and a stable layer in the tropopause region. These turbulent plumes likely arose as the result of entrainment at the stable layer interface produced by still active turbulent mixing. Statistics on the characteristics of the KH billows are also presented. Large‐amplitude KH billows in the lower atmosphere were only present less than 0.6% of the time and height. The typical depth, horizontal wavelength and depth‐to‐wavelength ratio of the KH braids are about 600 m, 2600 m and 0.22, respectively. They are thus relatively shallow and the quasi‐absence of layer splitting may suggest that they are more frequently generated when Ri falls just below 0.25 (so that the large‐amplitude KH billows are not sufficiently energetic for breaking and mixing). Vertical shears of horizontal wind are about 23 ms−1 km−1 on average. Finally, attempts at estimating (maximum) energy dissipation rate ε and (minimum) vertical eddy diffusivity K are made. Mean values of εmax and Kmin are typically ∼1 mW kg−1 (77% in the range 0.15–3.0 mW kg−1) and ∼5 m2 s−1 (70% in the range 1–10 m2 s−1), respectively. Copyright © 2011 Royal Meteorological Society
Observation of the marine atmospheric boundary layer in the Gulf of Guinea during the 2006 boreal spring
Authors: Leduc‐Leballeur Marion , Eymard L. , de Coëtlogon G.
Published: May 2011

In situ, satellite and model analyses data in April–July 2006 are used to investigate the links between sea surface temperature (SST) and the marine atmospheric boundary layer (MABL) in the Gulf of Guinea. The study region between 10°W and 6°E is divided into three areas with different characteristics: the North Area (4.5°N to 1°N) with the wettest atmosphere and the warmest SST, the Upwelling Area (1°N to 4°S) with the strongest SST decrease, and the South Area (4°S to 8°S) with a drier atmosphere and a more slowly decreasing SST than in the Upwelling Area. The key zone of the air‐sea interactions in this region seems to be the SST front between North and Upwelling Areas. On the one hand, the study of the MABL on either side of the front shows a well‐mixed layer between the surface and about 500 m high, sensitive to surface variations, which gets shallower (deeper) when the SST decreases (increases). The MABL height (about 1500 m) follows the same variations but is not exactly collocated with the SST variations. On the other hand, the observation of the MABL across the SST front shows a strengthening of southeasterlies in the South Area coinciding with a strong SST decrease in the Upwelling Area. In the latter, the wind weakens above the colder SST. Besides, in the North Area, the wind strengthens above the warmer SST. However, the wind acceleration spans from the equator to 2°N in April and as far as 4°N in June. A convergence zone is observed in the vicinity of 2°N in April, suggesting a convection activity there, favoured by the SST front. Copyright © 2011 Royal Meteorological Society
Cooperative control of autonomous systems
Authors: Holsapple Raymond W. , Kingston Derek B.
Published: May 2011

This special issue contains a collection of papers on task assignment problems, path planning problems, cooperative control problems and coordinated control problems. Each of the authors has concentrated his or her efforts on both theory development and application to enhance the overall academic contribution of each paper. The theme of this special issue was motivated by the many collaborations of the Cooperative and Intelligent Control of Unmanned Aerial Vehicles (UAV) group in the Control Science Center of Excellence of the Air Force Research Laboratory (AFRL). Published 2011. This article is a US Government work and is in the public domain in the USA.
Positive state‐bounding observer for positive interval continuous‐time systems with time delay
Authors: Li Ping , Lam James
Published: May 2011

This paper is concerned with the problem of positive observer synthesis for positive systems with both interval parameter uncertainties and time delay. Conventional observers may no longer be applicable for such kind of systems due to the positivity constraint on the observers, and they only provide an estimate of the system state in an asymptotic way. A pair of positive observers with state‐bounding feature is proposed to estimate the state of positive systems at all times in this paper. A necessary and sufficient condition for the existence of desired observers is first established, and the observer matrices can be obtained easily through the solutions of a set of linear matrix inequalities (LMIs). Then, to reduce the error signal between the system state and its estimates, an iterative LMI algorithm is developed to compute the optimized state‐bounding observer matrices. Finally, a numerical example is presented to show the effectiveness and applicability of the theoretical results. Copyright © 2011 John Wiley & Sons, Ltd.
Magnetoresponsive On‐Demand Release of Hybrid Liposomes Formed from Fe3O4 Nanoparticles and Thermosensitive Block Copolymers
Authors: Katagiri Kiyofumi , Imai Yuji , Koumoto Kunihito , Kaiden Tomohiro , Kono Kenji , Aoshima Sadahito
Published: May 2011

A new approach to control the release of encapsulated materials from liposomes by using thermosensitive block copolymers and magnetic nanoparticles is reported. Hydrophobized Fe3O4 nanoparticles are synthesized via the hydrothermal process, and can be incorporated into liposomal membranes by hydrophobic interactions. Thermosensitive block copolymers of (2‐ethoxy)ethoxyethyl vinyl ether (EOEOVE) and octadecyl vinyl ether (ODVE) are synthesized by living cationic polymerization. The poly(EOEOVE) block acts as a temperature‐sensitive moiety, and the poly(ODVE) block acts as an anchor unit. Hybrid liposomes encapsulating pyranine, a water‐soluble fluorescent dye, are prepared from mixtures of phospholipids, the hydrophobized Fe3O4 nanoparticles, and the copolymer. While the hybrid liposomes released negligible amounts of pyranine under static conditions, the release of pyranine is drastically enhanced by alternating magnetic field irradiation. The magnetically induced release is attributed to the transition of the thermosensitive segment of the copolymer, which is caused by the release of localized heat from the Fe3O4 nanoparticles under magnetic stimuli, rather than the rupture of the capsules. The release rate of the hybrid capsules is controlled by varying the amount of Fe3O4 nanoparticles embedded into the liposomes.