bluuebunny/crossref_metadata_2025 huggingface dataset:
Sensory Processing, Physiological Stress, and Sleep Behaviors in Children with and without Autism Spectrum Disorders
Authors: Reynolds Stacey , Lane Shelly J. , Thacker Leroy
Published: May 2011

Sleep problems have been frequently identified in children with autism spectrum disorders (ASD). It has been proposed that some sleep problems are due to sensory sensitivity. The purpose of this study was to examine the relationship between physiologic responses to sensation and sleep in children with and without ASD. Fifty-five children participated in the study (ASD, n = 27; typical, n = 28). All children participated in a sensory challenge laboratory protocol. Electrodermal reactivity and salivary cortisol were used as physiological indicators of sensory responsivity. Behavioral data were collected using the Sensory Profile and the Child Behavior Checklist. Results confirmed that children with ASD have a higher prevalence of atypical sensory behaviors and sleep disturbances than typical children. Behavioral and physiological measures were able to predict good sleepers versus poor sleepers with 85.7% accuracy, suggesting that atypical sensory behaviors are important to consider in relation to sleep deficits in children.
Basophils, IgE, and Autoantibody-Mediated Kidney Disease
Authors: Bosch Xavier , Lozano Francisco , Cervera Ricard , Ramos-Casals Manuel , Min Booki
Published: May 2011

Basophils are of interest in immunology due to their ability to produce a Th2-signature cytokine, IL-4, following activation. A new understanding of the role of basophils in immunity shows novel functions at a cellular level through which basophils influence adaptive immunity. This review summarizes new advances in basophil biology and discusses new roles for basophils in human disease, especially in the mediation of the pathogenesis of lupus nephritis. Recently, basophils have been shown to contribute to self-reactive Ab production in systemic lupus erythematosus and may enhance pre-existing loss of B cell tolerance, suggesting that basophils, IL-4, and IgE mediate the pathogenesis of lupus nephritis by promoting the Th2 environment and activating autoreactive B cells. In addition to envisaging exciting therapeutic prospects, these novel findings open the way for the study of basophils in other autoimmune and renal diseases.
Complemented Subspaces of Linear Bounded Operators
Authors: Bahreini Manijeh , Bator Elizabeth , Ghenciu Ioana
Published: May 2011

We study the complementation of the spaceW(X,Y) of weakly compact operators, the spaceK(X,Y) of compact operators, the spaceU(X,Y) of unconditionally converging operators, and the spaceCC(X,Y) of completely continuous operators in the spaceL(X,Y) of bounded linear operators fromXtoY. Feder proved that ifXis infinite-dimensional andc0↪Y, thenK(X,Y) is uncomplemented inL(X,Y). Emmanuele and John showed that ifc0↪K(X,Y), thenK(X,Y) is uncomplemented inL(X,Y). Bator and Lewis showed that ifXis not a Grothendieck space andc0↪Y, thenW(X,Y) is uncomplemented inL(X,Y). In this paper, classical results of Kalton and separably determined operator ideals with property (∗) are used to obtain complementation results that yield these theorems as corollaries.
Casimir Operators and Nilpotent Radicals
Authors: Ndogmo J. C.
Published: May 2011

It is shown that a Lie algebra having a nilpotent radical has a fundamental set of invariants consisting of Casimir operators. A different proof is given in the well known special case of an abelian radical. A result relating the number of invariants to the dimension of the Cartan subalgebra is also established.
Ice nuclei properties within a Saharan dust event at the Jungfraujoch in the Swiss Alps
Authors: Chou C. , Stetzer O. , Weingartner E. , Jurányi Z. , Kanji Z. A. , Lohmann U.
Published: May 2011

Abstract. The new portable ice nucleation chamber (PINC) developed by the Institute for Atmospheric and Climate Sciences of ETH Zurich was operated during two measurement campaigns at the high alpine research station Jungfraujoch situated at 3580 m a.s.l, in March and June 2009. During this time of the year, a high probability of Saharan dust events (SDE) at the Jungfraujoch has been observed. We used an impactor with a cutoff size of 1 μm aerodynamic diameter and operated the system at −31 °C and relative humidities of 127 % and 91 % with respect to ice and water, respectively. Investigation of the ambient number concentration of ice nuclei (IN) in the deposition nucleation mode and during a SDE in the free troposphere is reported. The results discussed in this paper are the first continuous IN measurements over a period of several days at the Jungfraujoch. The average IN concentration found during the campaign in March was 8 particles per liter whereas during the campaign in June, the average number concentration was higher up to 14 particles per liter. Two SDEs were detected on 15 and 16 June 2009. Our measurements show that the SDEs had IN number concentration up to several hundreds per liter. We found the best correlation between the number concentration of the larger particle fraction measured by an optical particle counter and the IN number concentration during a Saharan dust event. This correlation factor is higher for particles larger than 0.5 μm meaning that a higher concentration of larger particles induced higher IN number concentration. No correlation could be found between the black carbon mass concentration and the variations in IN number concentration.
Data validation procedures in agricultural meteorology – a prerequisite for their use
Authors: Estévez J. , Gavilán P. , García-Marín A. P.
Published: May 2011

Abstract. Quality meteorological data sources are critical to scientists, engineers, climate assessments and to make climate related decisions. Accurate quantification of reference evapotranspiration (ET0) in irrigated agriculture is crucial for optimizing crop production, planning and managing irrigation, and for using water resources efficiently. Validation of data insures that the information needed is been properly generated, identifies incorrect values and detects problems that require immediate maintenance attention. The Agroclimatic Information Network of Andalusia at present provides daily estimations of ET0 using meteorological information collected by nearly of one hundred automatic weather stations. It is currently used for technicians and farmers to generate irrigation schedules. Data validation is essential in this context and then, diverse quality control procedures have been applied for each station. Daily average of several meteorological variables were analysed (air temperature, relative humidity and rainfall). The main objective of this study was to develop a quality control system for daily meteorological data which could be applied on any platform and using open source code. Each procedure will either accept the datum as being true or reject the datum and label it as an outlier. The number of outliers for each variable is related to a dynamic range used on each test. Finally, geographical distribution of the outliers was analysed. The study underscores the fact that it is necessary to use different ranges for each station, variable and test to keep the rate of error uniform across the region.
Impact of climate change on the stream flow of the lower Brahmaputra: trends in high and low flows based on discharge-weighted ensemble modelling
Authors: Gain A. K. , Immerzeel W. W. , Sperna Weiland F. C. , Bierkens M. F. P.
Published: May 2011

Abstract. Climate change is likely to have significant effects on the hydrology. The Ganges-Brahmaputra river basin is one of the most vulnerable areas in the world as it is subject to the combined effects of glacier melt, extreme monsoon rainfall and sea level rise. To what extent climate change will impact river flow in the Brahmaputra basin is yet unclear, as climate model studies show ambiguous results. In this study we investigate the effect of climate change on both low and high flows of the lower Brahmaputra. We apply a novel method of discharge-weighted ensemble modeling using model outputs from a global hydrological models forced with 12 different global climate models (GCMs). Our analysis shows that only a limited number of GCMs are required to reconstruct observed discharge. Based on the GCM outputs and long-term records of observed flow at Bahadurabad station, our method results in a multi-model weighted ensemble of transient stream flow for the period 1961–2100. Using the constructed transients, we subsequently project future trends in low and high river flow. The analysis shows that extreme low flow conditions are likely to occur less frequent in the future. However a very strong increase in peak flows is projected, which may, in combination with projected sea level change, have devastating effects for Bangladesh. The methods presented in this study are more widely applicable, in that existing multi-model streamflow simulations from global hydrological models can be weighted against observed streamflow data to assess at first order the effects of climate change for specific river basins.
Increasing parameter certainty and data utility through multi-objective calibration of a spatially distributed temperature and solute model
Authors: Bandaragoda C. , Neilson B. T.
Published: May 2011

Abstract. To support the goal of distributed hydrologic and instream model predictions based on physical processes, we explore multi-dimensional parameterization determined by a broad set of observations. We present a systematic approach to using various data types at spatially distributed locations to decrease parameter bounds sampled within calibration algorithms that ultimately provide information regarding the extent of individual processes represented within the model structure. Through the use of a simulation matrix, parameter sets are first locally optimized by fitting the respective data at one or two locations and then the best results are selected to resolve which parameter sets perform best at all locations, or globally. This approach is illustrated using the Two-Zone Temperature and Solute (TZTS) model for a case study in the Virgin River, Utah, USA, where temperature and solute tracer data were collected at multiple locations and zones within the river that represent the fate and transport of both heat and solute through the study reach. The result was a narrowed parameter space and increased parameter certainty which, based on our results, would not have been as successful if only single objective algorithms were used. We also found that the global optimum is best defined by multiple spatially distributed local optima, which supports the hypothesis that there is a discrete and narrowly bounded parameter range that represents the processes controlling the dominant hydrologic responses. Further, we illustrate that the optimization process itself can be used to determine which observed responses and locations are most useful for estimating the parameters that result in a global fit to guide future data collection efforts.
Visual Quality after Acrysof IQ ReSTOR Intraocular Lens Implantation in Eyes with High Myopia
Authors: Wang Qing , Zhao Guiqiu , Wang Qian , Jia Wenyan
Published: May 2011

Purpose

To evaluate the visual performance of patients with high myopia with diffractive multifocal intraocular lens (MIOL) as compared with aspheric monofocal intraocular lens (IOL).

Methods

A prospective nonrandomized controlled study was conducted. Consecutively, 36 patients with senile cataract (72 eyes) received phacoemulsification and IOL implantation: 12 patients (24 eyes) were implanted with AcrySof IQ ReSTOR SN6AD3 IOL, 12 patients (24 eyes) were implanted with AcrySof IQ ReSTOR SN6AD1 IOL, and another 12 patients (24 eyes) were implanted with AcrySof IQ SN60WF as control group. All patients were assessed at 6 months postoperatively in these aspects: uncorrected and best-corrected visual acuities for distance (5 mo), intermediate (60 cm), and near (30 cm), modulation transfer function, and defocus curve. Patient satisfaction (spectacle independence, glare or halo disturbance, and overall satisfaction) was assessed by a questionnaire.

Results

At 6 months postoperatively, both uncorrected and distance-corrected intermediate and near visual acuity were significantly better in multifocal groups than the control monofocal group (p<0.01). Intermediate visual acuity in the SN6AD1 group was a little higher than that in the SN6AD3 group (p<0.05); conversely, the near visual acuity in the SN6AD3 group was better than in the SN6AD1 group (p<0.05). Modulation transfer function with a 5.0-mm aperture was similar in the 3 groups and there was no statistically significant difference. Patients in both multifocal groups reported excellent overall spectacle independence and satisfaction with the IOLs.

Conclusions

Compared with aspheric monofocal IOL, AcrySof ReSTOR IQ multifocal IOLs could provide a functional vision range from near to distance, resulting in high level of spectacle independence and satisfaction among patients with high myopia.
Electronic Trap States in Methanofullerenes
Authors: Schafferhans Julia , Deibel Carsten , Dyakonov Vladimir
Published: May 2011

The trap states in three fullerene derivatives, namely PC61BM ([6,6]‐phenyl C61 butyric acid methyl ester), bisPC61BM (bis[6,6]‐phenyl C61 butyric acid methyl ester) and PC71BM ([6,6]‐phenyl C71 butyric acid methyl ester), are investigated by means of thermally stimulated current measurements (TSC). Thereby, the lower limit of the trap densities for all studied methanofullerenes is on the order of 1022 m−3, with the highest trap density in bisPC61BM and the lowest in PC61BM. Fractional TSC measurements on PC61BM reveal a broad trap distribution instead of discrete trap levels, with activation energies ranging from 15 meV to 270 meV and the maximum at about 75 meV. The activation energies of the most prominent traps in the other two fullerene derivatives are significantly higher, at 96 meV and 223 meV for PC71BM and 184 meV for bisPC61BM, respectively. The influence of these findings on the performance of organic solar cells is discussed.
Cortical bone mass and geometry: Age, sex, and intraskeletal variation in nineteenth‐century Euro‐Canadians
Authors: Doyle L. Elizabeth , Lazenby Richard A. , Pfeiffer Susan
Published: May 2011

Objectives:

This study seeks to understand the interaction of cortical bone strength and mass within individuals and across age‐groups in male and female adults from a relatively active, long‐lived nineteenth‐century Euro‐Canadian population.

Methods:

Strength and relative cortical area are measured in paired femora (weight‐bearing elements) and metacarpals (manipulative elements) from 139 adults (M = 82; F = 52). Sex and age patterns are tested using linear multiple regression and analysis of covariance. Intra‐individual divergence between femora and metacarpals is quantified using the Pearson residual from regression of femur on metacarpal values. Association of residuals with age is tested with curve estimation, factorial analysis of variance and X2 tests.

Results:

Strength is maintained but cortical mass declines with age. In females, the slope of cortical mass against age is steeper in the metacarpal than in the femur. However, the degree of divergence between femur and metacarpal within individuals does not increase clearly with age.

Conclusions:

Age change in bone strength is systemically controlled and homeostatic, but change in bone mass may vary with limb‐specific mechanical environment, particularly in females. However, the distribution of within‐individual divergence between femur and metacarpal values suggests that idiosyncratic factors, rather than age, have the strongest influence on intraskeletal divergence. Attempts to reconstruct skeletal ageing in past populations may benefit from an approach that models whole‐bone integrity, rather than bone mass alone, and that represents age‐related variation in both weight‐bearing and nonweight‐bearing sites. Am. J. Hum. Biol., 2011. © 2011 Wiley‐Liss, Inc.
Polymerization of acrylamide in a micellar medium: Inhibition effect of surfactants
Authors: Niranjan P. S. , Tiwari Amit Kumar , Upadhyay Santosh Kumar
Published: May 2011

The polymerization of acrylamide (AM) in an aqueous medium and in the presence of anionic [sodium lauryl sulfates (NaLS)], cationic [cetyltrimethyl ammonium bromide (CTAB)], and nonionic (Brij‐35) surfactants was carried out at 60°C with potassium persulfate as the initiator. The percentage conversion and rate of polymerization (Rp) decreased in the presence of the surfactant, and the inhibition effect of the surfactant was in the order CTAB > Brij‐35 > NaLS. The viscosity data, namely, the intrinsic viscosity, viscosity‐average molecular weight, and shape factor, were also obtained in each case. The polymer was characterized by Fourier transform infrared spectroscopy and thermogravimetric analysis. The inhibition effect of the surfactant on Rp of AM was explainable on the basis of hydrophobic and electrostatic interactions during the association/binding between the surfactant and monomeric free radical of the monomer. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Study on the effect of inorganic salts on the alignment of electrospun fiber
Authors: Song Botao , Cui Wenguo , Chang Jiang
Published: May 2011

Well‐aligned and highly ordered architectures are always required in many fields, such as tissue engineering, electronics, and preparation of composite materials. In this study, electrospun mats with well‐aligned fibers and various fiber assemblies were successfully fabricated by electrospinning of poly(vinylbutyral) (PVB)/inorganic salt solution under the optimal salt condition. Then, the effect of inorganic salts on the degree of electrospun fiber alignment was comprehensively investigated, and the results indicated that the viscosity and conductivity of the solutions were the key factors influencing the degree of fiber alignment. It was expected that this simple and feasible method could be helpful for the fabrication of the well‐aligned electrospun fibers and various fiber assemblies. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Facile preparation of cds quantum dots using hyperbranched poly(amidoamine)s with hydrophobic end‐groups as nanoreactors
Authors: Shi Yunfeng , Liu Lanbo , Tu Chunlai , Zhu Lijuan , Yan Deyue , Li Guolin , Guo Fulin , Zhu Xinyuan
Published: May 2011

Hyperbranched poly(amidoamine)s with methyl ester terminals (HPAMAM) were synthesized by one‐pot approach and subsequently used as nanoreactors to prepare CdS quantum dots (QDs). HPAMAM could bind Cd2+ through their internal amines, while the external methyl ester groups prevented the aggregation of polymers. After reaction with S2−, CdS QDs sequestered within individual hyperbranched polymers were obtained. The resulting CdS/HPAMAM nanocomposites were characterized by dynamic light scattering, transmission electron microscopy, ultraviolet‐visible spectroscopy, photoluminescence spectroscopy, and Fourier transform infrared spectroscopy, confirming the formation of CdS QDs with small particle size and narrow size‐distribution. Furthermore, the effects of Cd2+/S2− ratio and aging time on the photoluminescence of CdS QDs were also investigated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Construction of hemocompatible polycarbonate urethane with sulfoammonium zwitterionic polyethylene glycol
Authors: Guo Jintang , Feng Yakai , Ye Yaqin , Zhao Haiyang
Published: May 2011

The novel hydrophilic sulfoammonium zwitterionic polyethylene glycol (SAPEG) macromolecule was designed and synthesized using polyethylene glycol (PEG, Mw = 1000) as the starting agent. The sulfoammonium zwitterionic PEG was grafted onto polycarbonate urethane (PCU) via two ways: (1) direct grafting of SAPEG onto PCU using diisocyanate as a spacer; (2) grafting of PEG mono(N,N‐dimethyl glycine)ester (APEG) onto the PCU with diisocyanate, and then reacting with 1,3‐propanesulfone via ring‐opening reaction to form sulfoammonium zwitterionic structure. The X‐ray photoelectron spectroscopy (XPS) was used to analyze the elements of the grafted materials. The results showed that the sulfur contents on the modified PCU were 0.5 and 0.9% for both grafting methods, respectively, indicating sulfoammonium zwitterionic PEG has successfully been grafted onto PCU chains. The low‐water contact angle showed that the modified PCUs were higher hydrophilic than unmodified PCU. The results of hemolysis test and cytotoxicity test indicated that blood compatibility of the modified PCU was better than that of the unmodified PCU. The modified PCUs are preferred candidates for blood‐contacting implants or devices due to the hemocompatibility and nontoxicity in vitro. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Dielectric barrier discharge plasma induced surface modification of polyester/cotton blended fabrics to impart water repellency using HMDSO
Authors: Palaskar Shital , Kale Kiran H. , Nadiger G. S. , Desai A. N.
Published: May 2011

Continuous treatment of polyester/cotton blended fabric samples was carried with hexamethyldisiloxane (HMDSO) plasma on the pilot scale atmospheric pressure plasma reactor. The mixture of helium and argon was used as carrier gas for generating dielectric barrier discharge plasma. The effect of discharge power and treatment time on the water repellent properties of samples were evaluated with contact angle (CA) and spray test measurements. Spray test and CA results showed improved resistance to wetting with water. The effect of discharge conditions on the surface morphology and surface chemistry of plasma treated samples were investigated by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopic analysis, respectively. The presence of Si‐O‐Si and Si‐CH3groups in the structure of plasma polymer deposited at the surface of P/C samples was revealed by FTIR spectroscopy. Further, structural differences in HMDSO plasma polymer deposited under different discharge conditions were reported with reference to organic/inorganic nature of plasma polymer. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.
Stability of two‐phase polymerization of acrylamide in aqueous poly(ethylene glycol) solution
Authors: Lü Ting , Shan Guorong , Shang Songmin
Published: May 2011

A poly(acrylamide) (PAM) aqueous dispersion with high solid was successfully synthesized through two‐phase polymerization of acrylamide (AM) in aqueous poly(ethylene glycol) (PEG) solution. To prepare stable PAM aqueous dispersion, the effects of initiator, monomer and PEG concentration on the stability of the aqueous two‐phase polymerization system were investigated in detail. Dynamic light scattering (DLS) was applied to study the evolution of the size and size distribution of the aqueous PAM droplet in the initial stage of polymerization. A droplet aggregation period was found in the initial stage, in which the PAM coagulum is easy to be generated below the conversion of about 5% due to high polymerization rate. By analyzing the effects of PEG on the stability of this polymerization system, it was found that PEG plays both precipitant and stabilizer role. When PEG concentration ranges from 12 to 24%, increasing its use would promote the droplet stabilization; however, when PEG concentration exceeds 28%, increasing its use may accelerate the droplet formation which does not further favor the droplet stabilization. Furthermore, the viscosity evolution during the polymerization under various reaction conditions was determined by rotational viscometer on line. When monomer concentration exceeded 8%, increasing the initiator or monomer concentration would result in that the polymer produced in the continuous phase could not be separated in time due to the high viscosity. All these results demonstrated that the slower the polymerization rate is, the more stable PAM aqueous dispersion will be. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Acrylonitrile/acrylamidoxime/2‐acrylamido‐2‐ methylpropane sulfonic acid‐based hydrogels: Synthesis, characterization and their application in the removal of heavy metals
Authors: Atta Ayman M. , Ismail Husein S. , Mohamed Hamed M. , Mohamed Zakaa M.
Published: May 2011

Crosslinked acrylonitrile/acrylamidoxime/2‐acrylamido‐2‐methylpropane sulfonic acid (AN/AAx/AMPS)‐based hydrogels were prepared by free radical crosslinking solution polymerization technique. The chemical structures of the hydrogels were characterized by FT‐IR analysis. The morphology of the dry hydrogel sample was examined by scanning electron microscope (SEM). These hydrogels were used for the removal of Cd(II), Cu(II), and Fe(III) ions from their aqueous solutions. The influence of the uptake conditions such as pH, time and initial feed concentration on the metal ion binding capacity of hydrogel was also tested. The selectivity of the hydrogel towards the different metal ions tested was arranged in the order of Cd(II) > Fe(III) > Cu(II). It was observed that the specific interaction between metal ions and ionic comonomer in the hydrogel affected the metal binding capacity of the hydrogel. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Structure of PAN precursor in thermal‐induced gel spinning
Authors: Chen Huifang , Du Weiping , Ye Wu , Pan Ding
Published: May 2011

The thermal‐induced gel spinning of polyacrylonitrile/dimethyl sulfoxide/water solutions were performed. The structure and performance of the PAN precursor fibers were characterized by mechanical properties testing, swelling capacity testing, scanning electron microscopy, and X‐ray diffraction. The effects of the water content, polymer concentration, coagulation bath temperature, and draw ratio on the cross‐sectional morphology, structure, and tensile properties are reported. The results show that 2% water content is optimal due to dispersed small pores found in the fibers' cross section. With the coagulating bath temperature decreased, the large pores in fibers also decreased. Large pores almost disappeared up to −9°C. The mechanical properties of the PAN fibers increased with the enhancement of PAN concentration, while the decrease of the coagulating bath temperature or water content would induce the improvement of the fibers' mechanical properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Electrochemical immobilization of ascorbate oxidase in poly(3,4‐ethylenedioxythiophene)/multiwalled carbon nanotubes composite films
Authors: Liu Ming , Wen Yangping , Li Dong , He Haohua , Xu Jingkun , Liu Congcong , Yue Ruirui , Lu Baoyang , Liu Guodong
Published: May 2011

Immobilization of ascorbate oxidase (AO) in poly(3,4‐ethylenedioxythiophene) (PEDOT)/multiwalled carbon nanotubes (MWCNTs) composite films was achieved by one‐step electrochemical polymerization. The PEDOT/MWCNTs/AO modified electrode was fabricated by the entrapment of enzyme in conducting matrices during electrochemical polymerization. The PEDOT/MWCNTs modified electrodes were investigated by cyclic voltammetry and electrochemical impedance spectroscopy. The experimental results showed that the composite films exhibited better mechanical integrity, electrochemical activity, higher electronic and ionic conductivity, and larger redox capacitance compared with pure PEDOT films, which would be beneficial to the fabrication of PEDOT/MWCNTs/AO electrochemical biosensors. The scanning electron microscopy studies revealed that MWCNTs served as backbone for 3,4‐ethylenedioxythiophene (EDOT) electropolymerization. Furthermore, the resulting enzyme electrode could be used to determine L‐ascorbic acid successfully, which demonstrated the good bioelectrochemical catalytic activity of the immobilized AO. The results indicated that the PEDOT/MWCNTs composite are a good candidate material for the immobilization of AO in the fabrication of enzyme‐based biosensor. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
New polyamides and polyesteramides incorporated with bis(carboxy‐substituted) hydrazines: Synthesis and characterization
Authors: Kandile Nadia G. , Nasr Abir S.
Published: May 2011

The present article endeavors to synthesize new polyamides via direct polycondensation of various diamines [hexamethylene diamine, ρ‐phenylene diamine, 2,5‐bis(m‐aminobenzylidene) cyclopentanone, and 2,6‐bis(m‐aminobenzylidene)cyclohexanone] with different bis(carboxy‐substituted) hydrazines such as [1,2‐bis(3‐carboxy acrylyl)hydrazine and 1,2‐bis(3‐carboxybenzoyl) hydrazine]. The polycondensation reaction of 1,2‐bis(3‐p‐hydroxyanilide acrylyl) hydrazine with the same bis(carboxy‐substituted) hydrazines gave polyester amides. The polycondensation process was run in the presence of CaCl2, triethylphosphite, and pyridine as a catalyst. These polymers were characterized by FTIR, 1H‐NMR, solubility, TGA, DSC, X‐ray, mechanical properties, and electrical conductivity. The electrical conductivity measurements showed that all new polymers show promise as insulators. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Modelling the effect of venous disease on quality of life
Authors: Carradice D , Mazari F A K , Samuel N , Allgar V , Hatfield J , Chetter I C
Published: May 2011

Background

A clear understanding of the relationship between venous reflux, clinical venous disease and the effects on quality of life (QoL) remains elusive. This study aimed to explore the impact of venous disease, and assess any incremental direct effect of progressive disease on health-related QoL, with the ultimate aim to model venous morbidity.

Methods

Consecutive patients with venous disease were assessed for inclusion in the study. Patients with isolated, unilateral, single superficial axial incompetence diagnosed on duplex imaging were included. Clinical grading was performed with the Clinical Etiologic Anatomic Pathophysiologic (CEAP) classification and Venous Clinical Severity Score (VCSS). Patients completed generic (Short Form 36, SF-36®; EuroQol 5D, EQ-5D™) and disease-specific (Aberdeen Varicose Vein Questionnaire, AVVQ) QoL instruments. Multivariable regression modelling was performed, taking account of demographic and anatomical factors, to explore the effect of clinical severity on QoL impairment.

Results

Some 456 patients with C2–6 venous disease were included, along with control data for 105 people with C0–1 disease. Increasing clinical grade corresponded strongly with deterioration in disease-specific QoL (P < 0·001). This could be stratified into three distinguishable groups: C0–1, C2–4 and C5–6 (P < 0·001 to P = 0·006). Increasing clinical grade also corresponded with deterioration in the physical domains of SF-36® (P < 0·001 to P = 0·016), along with EQ-5D™ index utility (quality-adjusted life year) scores (P < 0·001).

Conclusion

Demonstrable morbidity was seen, even with uncomplicated venous disease. The physical impairment seen with venous ulceration was comparable with that seen in congestive cardiac failure and chronic lung disease.
Role of Disulfide Bridges in Archaeal Family‐B DNA Polymerases
Authors: Killelea Tom , Connolly Bernard A.
Published: May 2011

The family‐B DNA polymerases obtained from the order Thermococcales, for example, Pyrococcus furiosus (Pfu‐Pol) are commonly used in the polymerase chain reaction (PCR) because of their high thermostability and low error rates. Most of these polymerases contain four cysteines, arranged as two disulfide bridges. With Pfu‐Pol C429–C443 forms one of the disulfides (DB1) and C507–C510 (DB2) the other. Although the disulfides are well conserved in the enzymes from the hyperthermophilic Thermococcales, they are less prevalent in euryarchaeal polymerases from other orders, and tend to be only found in other hyperthermophiles. Here, we report on the effects of deleting the disulfide bridges by mutating the relevant cysteines to serines. A variety of techniques, including differential scanning calorimetry and differential scanning fluorimetry, have shown that both disulfides make a contribution to thermostability, with DB1 being more important than DB2. However, even when both disulfides are removed, sufficient thermostability remains for normal (identical to the wild type) performance in PCR and quantitative (real‐time) PCR. Therefore, polymerases totally lacking cysteine are fully compatible with most PCR‐based applications. This observation opens the way to further engineering of polymerases by introduction of a single cysteine followed by appropriate chemical modification.
The inclined settling of dispersed suspensions of spherical particles in square‐section tubes
Authors: Oliver D. R. , Jenson V. G.
Published: May 2011

It has been known since 1920 that thing a tube containing a suspension increases the settling rate. The theory of Nakamura and Kuroda is shown to predict both an experimental and theoretical upper limit to this improvement. A small square‐section tube resting on an edge or on a corner is used to study the sculling of suspensions of closely‐sized spherical particles, four concentrations being used at five inclinations to the vertical.

The initial settling rate shows no improvement over that obtained in a vertical tube, but a clarified layer is soon formed on the upper inclined face. Hydrodynamic forces then develop which transfer this liquid to the upper surface, thus augmenting the natural settling rate by factors as great as six or seven for the present tube geometry.

By introducing a parameter to allow for the resistance to flow within the clarified layer, it is possible to predict the observed behavior on a theoretical basis. In particular, the effect of the concentration of the solid particles on the shape of the settling rate curves is shown to be a logical consequence of the properties of the system.
The pipeline flow of capsules: Part 7 ‐ an experimental investigation of the transport by two oils of single cylindrical and spherical capsules with density equal to that of the oil
Authors: Ellis H. S. , Bolt L. H.
Published: May 2011

Critical Reynolds numbers were revealed by the study at which the velocity ratio curves typically achieved minimum or maximum values. The pronounced critical condition at Reynolds number about 1,000 is of particular interest, falling as it does in the middle of the Reynolds number range widely regarded as yielding laminar flow in a long circular pipe, but coinciding with the first manifestations of turbulence reported in previous studies.

Velocity ratios for both spherical and cylindrical capsules were found to vary from about 1.10 to 1.75 in the laminar flow regime, and from 1.10 to 1.30 at the highest Reynolds numbers.
Mass transfer from solid spheres
Authors: Keey R. B. , Glen J. B.
Published: May 2011

The authors investigate the applicability of the relationship

Nsh = A + B NmRe NnSc

to determine over‐all mass transfer rates in forced convection from single solid spheres, where A, B, m and n are presumed to be constants. This expression is shown to be not entirely adequate and, in particular, the changing importance of the wake with increasing Reynolds number and turbulence in the boundary layer will affect these constants.
The Impact of Snail (Bellamya aeruginosa) Bioturbation on Sediment Characteristics and Organic Carbon Fluxes in an Eutrophic Pond
Authors: Zheng Zhongming , Lv Jing , Lu Kaihong , Jin Chunhua , Zhu Jinyong , Liu Xiasong
Published: May 2011

A mesocosm experiment was conducted for 32 days in an eutrophic pond to study the effects of the bioturbation of the freshwater snail, Bellamya aeruginosa, on the benthic environment and to further understand cycling of organic carbon in water containing algal blooms. Chlorophyll‐a (chl‐a), phaeopigment, and organic matter contents of sediment, sediment oxygen consumption (SOC), and dissolved organic carbon (DOC) fluxes were determined on day 1, 16, and 32, respectively. The SOC decreased on day 16 and increased on day 32 significantly with the increase in snail density. DOC fluxes showed a net sediment uptake in all enclosures throughout the experiment. DOC fluxes in the high and mid density treatments were lower than those of the control. The concentrations of chl‐a and phaeopigment in the sediment increased significantly with snail density, indicating that the presence of snails reduced the biomass of phytoplankton. The results suggest that freshwater snails, B. aeruginosa, could influence the algal biomass (chl‐a) of small water bodies by their bioturbation effects on sediment characteristics and the fluxes of organic carbon.
Controlling NOx Emission of Crude Rice Bran Oil Blend for Sustainable Environment
Authors: Saravanan Subramani , Nagarajan Govindan , Ramanujam Radhakrishnan , Sampath Santhanam
Published: May 2011

The main objective of this work is to investigate the factors influencing the NOx control of a stationary diesel engine fuelled with crude rice bran oil blend with lesser effect on smoke density and brake thermal efficiency (BTE). Fuel injection timing, percentage of EGR, and fuel injection pressure are chosen as the factors for the objective and NOx emission, smoke density, and BTE are considered as the response variables. To critically analyze the effects of the chosen factors on the objective three levels were chosen in each factor and the experiments were designed by following the design of experiments method. Taguchi's L9 orthogonal array was used to conduct the tests with different combination of factor levels. Through analysis of variance (ANOVA) method, the most influencing factors and also the significance of each factor affecting each response variable were found out. Response graph was drawn for each response variable to determine the optimum combination of factor levels in achieving the objective and the obtained combination was confirmed experimentally.
Well‐posedness for the Navier Slip Thin‐Film equation in the case of partial wetting
Authors: Knüpfer Hans
Published: May 2011

Consider a viscous liquid droplet spreading on a surface. The classical slip condition at the liquid‐solid interface is the no‐slip condition. However, this condition yields infinite dissipation rate when the contact line moves (“no‐slip paradox”). For this reason other slip conditions such as the Navier slip condition have been proposed. We prove well‐posedness for a reduced 1‐D fluid model related to Navier slip. It turns out that the profile of the droplet cannot be described by a smooth function (not even for an initially smooth profile). However, existence and uniqueness can be proved in larger classes of spaces that allow for certain classes of singular expansions at the moving contact point. © 2011 Wiley Periodicals, Inc.
Growth and characterization of heavily doped silicon crystals
Authors: Scala R. , Porrini M. , Borionetti G.
Published: May 2011

Silicon crystals grown with the Czochralski method are still the most common material used for the production of electronic devices. In recent years, a growing need of large diameter crystals with increasingly higher doping levels is observed, especially to support the expanding market of discrete devices and its trend towards lower and lower resistivity levels for the silicon substrate. The growth of such heavily doped, large‐diameter crystals poses several new challenges to the crystal grower, and the presence of a high dopant concentration in the crystal affects significantly its main properties, requiring also the development of dedicated characterization techniques. This paper illustrates the recent advances in the growth and characterization of silicon crystals heavily doped with antimony, arsenic, phosphorus and boron. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experimental and theoretical aspects of the growth and equilibrium morphology of NaNO3
Authors: Benages Vilau R. , Costa E. , Bruno M. , Cuevas‐Diarte M. À. , Calvet i Pallas T. , Aquilano D.
Published: May 2011

Sodium nitrate (mineral nitratine, NaNO3, space group R $ \bar 3 $c at room temperature) is a material used in a great variety of fields, such as the molten salt technology. It is also of very interest from a crystallographic point of view, being iso‐structural with calcite (CaCO3). We performed several growth experiments in aqueous solution, near‐equilibrium, with the aim of finding the ideal conditions for investigating both face‐by‐face growth kinetics and surface characterization, as well as the influence of K+ and Li+ ions on the growth morphology. Single {10.4} rhombohedral crystals have been systematically grown from pure aqueous solution, while {00.1} truncated rhombohedra were obtained in the presence of K+ and Li+ ions in the mother solution. When determining the theoretical equilibrium morphology of NaNO3 crystals, the {00.1} and {10.4} surfaces were studied by using the 2D‐slab model and relaxed and athermal surface energies (surfaces energies at T = 0 K) were evaluated at DFT level (B3LYP Hamiltonian) by using the CRYSTAL06 package. The {00.1} dipolar surfaces were reconstructed by the octopolar Hartman‐Lacmann's model, already proposed for NaCl‐like lattices. This type of reconstruction is the only one which respects the bulk symmetry of the crystal. The octopolar Na+ terminated {00.1} form resulted to be more stable than the NO3– terminated one. However, the {00.1} form does not enter the theoretical athermal equilibrium shape of nitratine crystals, being γ(10.4)Na=160, γ(00.1)Na= 695 and γ(00.1)NO3=1535 erg/cm2. Finally, a simple 2D‐epitaxy model is proposed to explain the appearance of NaNO3{00.1} truncated rhombohedra in the presence of K+ and Li+ ions. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Haze in sapphire crystals grown by SAPMAC method
Authors: Zhang Lunyong , Zuo Hongbo , Zhou Ji , Sun Jianfei , Xing Dawei , Han Jiecai
Published: May 2011

Haze defect in SAPMAC method grown sapphire crystal was studied in detail. It is shown that haze is composed by a large number of CO2 bubbles, and haze always appears in the axis region of the crystal since the bubbles formed in front of the crystallization surface are most always draged to the convection rolls in front of the central part of the crystallizaiton surface by melt and then engulfed by the rolls. Moreover, the effects of pulling rate on the formation of haze were analyzed and means for restraining haze was suggested. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of Humidity and UV Assistance on the Properties of Erbium Doped Yttrium Oxide Films Prepared by Aerosol‐MOCVD
Authors: Salhi Rached , Roussel Herve , Chaudouët Patrick , Maalej Ramzi , Fourati Mohieddine , Deschanvres Jean‐Luc
Published: May 2011

Erbium‐doped yttrium oxide films are prepared from yttrium acetylacetonate (Y(C5H7O2)3) and erbium (III) tris(2,2,6,6‐tetramethyl‐3,5‐heptanedionate) (Er(TMHD)3) under standard conditions by UV‐aerosol‐assisted metal‐organic (AA‐MOCVD), using air with controlled humidity as the carrier gas. The structure and deposition rate are optimized by studying three experimental parameters; substrate temperature, relative humidity (RH) of the carrier gas, and UV‐assistance. Taking all these parameter effects under consideration, the maximum deposition rates are reached under low humidity air and with UV‐assistance. Nevertheless, as‐deposited Er:Y2O3 films crystallize in the Y2O3 cubic structure and present a very low organic contamination when depositions take place under high air humidity and with UV‐assistance. The refractive index of yttrium oxide films under these conditions are relatively high, reaching 1.86 when deposited at 410  °C.
Synthesis of 3′‐S‐Phosphonomethyl‐Modified Nucleoside Phosphonates with a 3′‐Deoxy‐3′‐thio‐α‐L‐threosyl Sugar Moiety
Authors: Huang Qiuya , Herdewijn Piet
Published: May 2011

The synthesis and antiviral evaluation of 3′‐deoxy‐3′‐S‐phosphonomethyl‐3′‐thio‐α‐L‐threosyl nucleosides as well as the 2′‐deoxy analogues related to PMDTT are described. The key transformations involved the synthesis of the 3′‐deoxy‐3′‐thio‐L‐threosyl and the 2′,3′‐dideoxy‐3′‐thio‐L‐threosyl derivatives by the Mitsunobu reaction. The phosphonate function was introduced by nucleophilic substitution and the glycosylation was carried out under Vorbrüggen conditions. None of these synthesized compounds showed significant in vitro activity against HIV, HCV, and RSV, or cytotoxicity.
Seismic control of single‐degree‐of‐freedom structure using tuned viscous mass damper
Authors: Ikago Kohju , Saito Kenji , Inoue Norio
Published: May 2011

In this study, we propose a new seismic control device, tuned viscous mass damper (TVMD), for building systems. We give a detailed description of an apparent mass amplifier using a ball‐screw mechanism, which is one of the most important components for realizing the new device. We also derive a closed‐form solution of an optimum seismic control design for a single‐degree‐of‐freedom structure subjected to harmonic excitation. The performance of the new device is compared with those of the conventional viscous damper and viscous mass damper systems. The vibration control system using the TVMD is shown to be the most effective for linear structural systems with dampers having the same additional damping coefficient. The effectiveness of the TVMD for seismic excitation is verified by analyses and shake table tests with a small‐scale TVMD. Copyright © 2011 John Wiley & Sons, Ltd.
Riffle‐pool morphometry and stage‐dependant morphodynamics of a large floodplain river (Vereinigte Mulde, Sachsen‐Anhalt, Germany)
Authors: Vetter Thomas
Published: May 2011

Riffle‐pool sequences are a common feature of gravel‐bed rivers. However, mechanisms of their generation and maintenance are still not fully understood. In this study a monitoring approach is employed that focuses on analysing cross‐sectional and longitudinal channel geometry of a large floodplain river (Vereinigte Mulde, Sachsen‐Anhalt, Germany) with a high temporal and spatial resolution, in order to conclude from stage‐dependant morphometric changes to riffle and pool maintaining processes.

In accordance with previous authors, pool cross‐sections of the Mulde River are narrow and riffle cross‐sections are wide suggesting that they should rather be addressed as two general types of channel cross‐sections than solely as bedforms. At high flows, riffles and pools in the study reaches changed in length and height but not in position. Pools were scoured and riffles aggraded, a development which was reversed during receding flows below the threshold of 0·4Qbf (40% bankfull discharge). An index for the longitudinal amplitude of riffle‐pool sequences, the bed undulation intensity or bedform amplitude, is introduced and proved to be highly significant as a form parameter, its first derivative as a process parameter. The process of pool scour and riffle fill is addressed as bedform maintenance or bedform accentuation. It is indicated by increasing longitudinal bed amplitudes.

According to the observed dynamics of bed amplitudes, maintenance of riffle‐pool sequences lags behind discharge peaks. Maximum bed amplitudes may be reached with a delay of several days after peak discharges. Increasing bed undulation intensity is interpreted to indicate bed mobility. Post‐flood decrease of the bed undulation intensity indicates a retrograde phase when transport from pools to riffles has ceased and bed mobility is restricted to riffle tails and heads of pools. This type of transport behaviour is referred to as disconnected mobility.

The comparison of two river reaches, one with undisturbed sediment supply, the other with sediment deficit, suggests that high bed undulation intensity values at low flows indicate sediment deficit and potentially channel degrading conditions. It is more generally hypothesized that channel bed undulations constitute a major component of form roughness and that increased bed amplitudes are an important feature of channel bed adjustment to sediment deficit be it temporally during late floods or permanently due to a supply limitation of bedload. Copyright © 2011 John Wiley & Sons, Ltd.