bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electro conductivities of well‐dispersed PMMA‐g‐MWNTs/6FDA‐based polyimide composites: Effect of chemical structure
Authors: Im Hyungu , Yun Sungjin , Kim Jooheon 
Published: February 2011

AbstractPMMA (polymethylmethacrylate), which is miscible with hexafluoropropane dianhydride (6FDA)‐based polyimide, was grafted onto MWNTs surfaces to enhance their dispersion relative to that of pristine MWNTs. The electrical conductivity of the 6FDA‐based composite revealed percolation threshold behavior, and the 6FDA‐4,4′‐(hexafluoroisopropylidene)diamine, (6FpDA):3,5‐diaminobenzoic acid (DABA)/PMMA‐g‐MWNT composite showed a higher percolation threshold concentration and a slightly lower critical exponent compared with those of the 6FDA‐6FpDA composite. Because of the weak interaction energies between 6FDA‐6FpDA:DABA and PMMA, agglomerated domains were formed. Also, the weak interaction energies of the 6FDA‐6FpDA:DABA led to a larger reduction in the normalized transmittance compared with that seen in the 6FDA‐6FpDA composite. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Free vibration of generally laminated plates with various shapes
Authors: Yousefi P. , Kargarnovin M.H. , Hosseini‐Hashemi S.H. 
Published: February 2011

AbstractThis article is focused on a simple approach for determining the natural frequency and mode shape of laminated angle‐ply plates with various shapes by rectangular orthotropy. Since the boundary of the domain for all shapes are not natural to the material coordinate axes it seems appropriate to express the plate displacement amplitude in terms of a polynomial and a general shape function multiplication in the x and y coordinates. The boundary conditions considered are clamped and simply supported edges. The effect of the fiber orientation, layer number, and lamination sequence on the natural frequencies of plates is also considered. The natural frequency determinant has been generated using the classical Rayleigh‐Ritz method. The algorithm developed can be used for a wide range of different plate shape having an internal hole, internal ring support, and any aspect ratio by simple programming. The natural frequencies and mode shapes of four cases of plate shape are obtained and some results were compared with those existing in the literature and analytical solution for simply supported rectangular plates with especially orthotropy. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Studies on transport of vapor and solute molecules through polyvinyl alcohol‐based clay containing nanocomposites
Authors: Sancha Rachna , Bajpai Jaya , Bajpai Anil K. 
Published: February 2011

AbstractThe present study focuses on fabricating of polymer–clay nanocomposites by in situ polymerization method and investigating their permeability behavior toward vapor and liquid molecules, thus, to evaluating barrier properties of the nanocomposites. For this purpose, acrylonitrile (AN) monomer was grafted on to poly(vinyl alcohol) (PVA) chains after the addition of very low amount of fuller's earth (clay) into polymer matrix using a suitable initiator, such as potassium persulphate (KPS), and crosslinker N‐N′ methylene bisacrylamide (MBA). The prepared nanomaterials were characterized by Fourier‐Transformation infrared (FTIR) spectroscopy and wide‐angle X‐ray diffraction (WXRD) techniques. The morphological features of designed materials were studied by scanning electron microscopy. The graft materials impregnated with fuller's earth were examined for their permeability behavior by observing the permeation of solute and vapor molecules from aqueous dye solution and volatile organic solvent, respectively. The composition of the nanocomposites and the amount of fuller's earth content were found to affect the passage of solute and vapor molecules across the nanocomposite membrane. The permeation capacity was quantified by evaluating permeability parameters. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Prenatal diagnosis of congenital vascular rings and slings: sonographic features and perinatal outcome in 81 consecutive cases
Authors: Li Shengli , Luo Guoyang , Norwitz Errol R. , Wang Chenhong , Ouyang Shuyuan , Yao Yuan , Chen Congying , Wen Huaxuan , Chen Xiulan , Bi Jingru 
Published: January 2011

AbstractObjectiveTo describe the sonographic features and perinatal outcome of congenital vascular rings diagnosed prenatally at a single tertiary care institution.MethodsAll cases of congenital vascular rings diagnosed by prenatal ultrasound between July 2005 and December 2009 were identified at a single referral center using an established perinatal database. The diagnosis was confirmed by postnatal echocardiography for live‐born infants or autopsy for terminated cases.ResultsThe overall incidence of vascular ring during this 5‐year period was 0.086% (81 cases among 94 321 women undergoing perinatal ultrasound examination). Forty‐four cases had complete O‐shaped (n = 3) or U‐shaped (n = 41) vascular rings, and 37 cases had incomplete C‐shaped vascular rings (vascular slings). The most common type of vascular ring seen in 50.6% (41/81) of cases was a right aortic arch with aberrant left subclavian artery. The second most common type was a left aortic arch with an aberrant right subclavian artery [39.5% (32/81)]. Chromosomal analysis was performed prenatally in 46 pregnancies, and six cases (13.0%) of fetal aneuploidy were identified.ConclusionsCongenital vascular rings can be diagnosed with prenatal ultrasound using the three‐vessel trachea view and subsequent fetal echocardiography with particular attention to the relationship of the aortic arches, ductal arches, and the trachea. Copyright © 2011 John Wiley & Sons, Ltd.
Accuracy of the Danish version of the ‘distress thermometer’
Authors: Bidstrup Pernille Envold , Mertz Birgitte Goldschmidt , Dalton Susanne Oksbjerg , Deltour Isabelle , Kroman Niels , Kehlet Henrik , Rottmann Nina , Gärtner Rune , Mitchell Alex J , Johansen Christoffer 
Published: January 2011

AbstractObjective: Short screening instruments have been suggested to improve the detection of psychological symptoms. We examined the accuracy of the Danish version of the ‘Distress Thermometer’.Methods: Between October 2008 and October 2009, 426 women with newly diagnosed primary breast cancer who were operated at the Breast Surgery Clinic of the Rigshospitalet, Copenhagen, were eligible for this study. Of these, 357 participated (84%) and 333 completed a questionnaire. The distress thermometer was evaluated against the ‘hospital anxiety and depression scale’ (HADS). We also examined the women's wish for referral for psychological support.Results: A cut‐off score of 6 vs 7 (low:⩽6, high:⩾7) on the distress thermometer was optimal for confirming distress, with a sensitivity of 42%, a specificity of 93%, a positive predictive value (PPV) of 78% and a negative predictive value (NPV) of 73%. A cut‐off score of 2 vs 3 was optimal for screening, with a sensitivity of 99%, a specificity of 36%, a PPV of 47% and a NPV of 99%. Of those who were distressed using the cut‐off score of 2 vs 3 on the distress thermometer, 17% (n = 41) wished to be referred for psychological support and 57% (n = 140) potentially wanted a later referral.Conclusion: The distress thermometer performed satisfactorily relative to the HADS in detecting distress in our study. A screening procedure in which application of the distress thermometer is a first step could be useful for identifying persons in need of support. Copyright © 2011 John Wiley & Sons, Ltd.
Pulmonary outcome of alport syndrome with familial diffuse esophageal leiomymatosis
Authors: Livnat Galit , Best Lael Anson , Guralnik Ludmila , Bentur Lea 
Published: January 2011

AbstractX‐linked Alport syndrome is associated in some families with diffuse leiomyomatosis. We describe herein, the pulmonary complications and outcome of three family members (mother, daughter, and son). The three underwent esophagectomy at different ages (22 years, three years, and 15 months respectively). Their current forced expiratory volume in the first second (FEV1) ranged from 33% in the mother to 60% in the daughter and 97% in the son. It is suggested that earlier intervention may lead to improved pulmonary function tests. Pediatr. Pulmonol. 2011; 46:614–616. © 2011 Wiley‐Liss, Inc.
Respiration rate monitoring methods: A review
Authors: AL‐Khalidi F.Q. , Saatchi R. , Burke D. , Elphick H. , Tan S. 
Published: January 2011

AbstractRespiration rate is an important indicator of a person's health, and thus it is monitored when performing clinical evaluations. There are different approaches for respiration monitoring, but generally they can be classed as contact or noncontact. For contact methods, the sensing device (or part of the instrument containing it) is attached to the subject's body. For noncontact approaches the monitoring is performed by an instrument that does not make any contact with the subject. In this article a review of respiration monitoring approaches (both contact and noncontact) is provided. Concerns related to the patient's recording comfort, recording hygiene, and the accuracy of respiration rate monitoring have resulted in the development of a number of noncontact respiration monitoring approaches. A description of thermal imaging based and vision based noncontact respiration monitoring approaches we are currently developing is provided. Pediatr. Pulmonol. 2011; 46:523–529. © 2011 Wiley‐Liss, Inc.
On the behaviour of nitrate esters in acid solution. III. Oxidation of ethanol by nitric acid in sulphuric acid
Authors: Camera E. , Modena G. , Zotti B. 
Published: January 2011

AbstractThe oxidation of ethanol as a model of the alcohols produced in the hydrolysis of nitrate esters, by nitric acid in aqueous sulphuric acid solutions has been studied with the aim to obtain information on the decomposition reaction of “spent acids”. The results show, in agreement with previous suggestions from this laboratory, that ethanol is firstly oxidized to acetaldehyde via a reaction initiated by nitric acid but carried on by NO2 radical. The latter is formed by the interaction of nitric and nitrous acids. The acetaldehyde is then oxidized by two independent paths leading one to acetic acid and the other to oxalic acid and eventually to CO2. The relevance of these findings on the understanding and on the control of „spent acids”︁ is briefly discussed.
Sur les lois de propagation des ondes de combustion dans les solides (Réactions pyrotechniques
Authors: Bernard M. L. 
Published: January 2011

AbstractOn the Propagation Laws of Combustion Waves in Solids (Pyrotechnic Reactions)The existing theoretical models accounting for the rate of propagation of combustion waves in solids involve conductive heat transfer. We show that in metal/oxidizer systems, this rate can be recalculated with satisfying accuracy from the thermal diffusivity. The size of the particles strongly effects this property. We suggest to represent the variability of pyrotechnical compositions by a “characteristic curve” which represents the variation of slowness of the combustion wave (v−1) as a function of the reciprocal of heat of reaction (|ΔH|−1).
Structure and properties of the potassium hydroxide‐dinitrobenzofuroxan adduct (KDNBF) and related explosive salts
Authors: Spear R. J. , Norris W. P. 
Published: January 2011

AbstractThe structure of KDNBF was previously shown to be as in formula (2), Mn+ = K+, a Meisenheimer complex of 4,6‐dinitrobenzofurazan‐1‐oxide and potassium hydroxide(3,4,5). The corresponding sodium, silver and barium salts are shown to have identical molecular structure to KDNBF on the basis of IR and NMR spectral data. Explosive properties of the four salts were determined. The barium salt is substantially less sensitive to thermal, electrostatic and mechanical stimulae relative to the other three salts.
Mechanical stability of multidomain proteins and novel mechanical clamps
Authors: Sikora Mateusz , Cieplak Marek 
Published: February 2011

AbstractWe estimate the size of mechanostability for 318 multidomain proteins which are single‐chain and contain up to 1021 amino acids. We predict existence of novel types of mechanical clamps in which interdomain contacts play an essential role. Mechanical clamps are structural regions which are the primary source of a protein's resistance to pulling. Among these clamps there is one that opposes tensile stress due to two domains swinging apart. This movement strains and then ruptures the contacts that hold the two domains together. Another clamp also involves tensile stress but it originates from an immobilization of a structural region by a surrounding knot‐loop (without involving any disulfide bonds). Still another mechanism involves shear between helical regions belonging to two domains. We also consider the amyloid‐prone cystatin C which provides an example of a two‐chain 3D domain‐swapped protein. We predict that this protein should withstand remarkably large stress, perhaps of order 800 pN, when inducing a shearing strain. The survey is generated through molecular dynamics simulations performed within a structure‐based coarse grained model. Proteins 2011; © 2011 Wiley‐Liss, Inc.
Colloidal Cu2ZnSnS4 nanocrystals generated by a facile route using ethylxanthate molecular precursors
Authors: Liu Yufeng , Ge Meiying , Yue Yang , Sun Yan , Wu Yizheng , Chen Xin , Dai Ning 
Published: February 2011

AbstractWe have demonstrated a flexible method for preparing Cu2ZnSnS4 (CZTS) nanocrystals by use of zinc ethylxanthate (Zn(ex)2) and copper ethylxanthate (Cu(ex)2). TEM, SEM, XRD, UV–vis, EDS, XPS and TG‐DTA indicate that the CZTS nanocrystals have been successfully synthesized. As air‐stable molecular precursors, Zn(ex)2 and Cu(ex)2 can optimize the synthesis of quaternary CZTS nanocrystals because Cu(ex)2 and Zn(ex)2 facilitate the formation of homogeneous precursor solutions including all precursors and then for the flexible production of CZTS nanocrystals in homogeneous reaction solutions. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hydrogen isotope correction for laser instrument measurement bias at low water vapor concentration using conventional isotope analyses: application to measurements from Mauna Loa Observatory, Hawaii
Authors: Johnson L. R. , Sharp Z. D. , Galewsky J. , Strong M. , Van Pelt A. D. , Dong F. , Noone D. 
Published: February 2011

AbstractThe hydrogen and oxygen isotope ratios of water vapor can be measured with commercially available laser spectroscopy analyzers in real time. Operation of the laser systems in relatively dry air is difficult because measurements are non‐linear as a function of humidity at low water concentrations. Here we use field‐based sampling coupled with traditional mass spectrometry techniques for assessing linearity and calibrating laser spectroscopy systems at low water vapor concentrations. Air samples are collected in an evacuated 2 L glass flask and the water is separated from the non‐condensable gases cryogenically. Approximately 2 µL of water are reduced to H2 gas and measured on an isotope ratio mass spectrometer.In a field experiment at the Mauna Loa Observatory (MLO), we ran Picarro and Los Gatos Research (LGR) laser analyzers for a period of 25 days in addition to periodic sample collection in evacuated flasks. When the two laser systems are corrected to the flask data, they are strongly coincident over the entire 25 days. The δ2H values were found to change by over 200‰ over 2.5 min as the boundary layer elevation changed relative to MLO. The δ2H values ranged from −106 to −332‰, and the δ18O values (uncorrected) ranged from −12 to −50‰. Raw data from laser analyzers in environments with low water vapor concentrations can be normalized to the international V‐SMOW scale by calibration to the flask data measured conventionally. Bias correction is especially critical for the accurate determination of deuterium excess in dry air. Copyright © 2011 John Wiley & Sons, Ltd.
Study of the desorption/ionization mechanism in electrospray droplet impact secondary ion mass spectrometry
Authors: Asakawa Daiki , Hiraoka Kenzo 
Published: February 2011

AbstractElectrospray droplet impact (EDI) secondary ion mass spectrometry (SIMS) is a desorption/ionization technique for mass spectrometry in which highly charged water clusters produced from an atmospheric‐pressure electrospray are accelerated in vacuum by several kV and impact on the sample deposited on the metal substrate. The abundances of the secondary ions for C60 and amino acids are measured as a function of the acceleration voltage of the primary charged water droplets. Two desorption/ionization mechanisms are suggested in the EDI ionization processes: low‐energy and high‐energy regimes. In the low‐energy regime, the excess charges in the primary droplets play a role in the formation of secondary ions. In the high‐energy regime, samples are ionized by the supersonic collision of the primary droplets with the sample. The yield of secondary ions increases by about three orders of magnitude with increase in the acceleration voltage of the primary droplets from 1.75 kV to 10 kV. Copyright © 2011 John Wiley & Sons, Ltd.
δ15N natural abundance in permafrost soil indicates impact of fire on nitrogen cycle
Authors: Conen Franz , Yakutin Mikhail V. , Puchnin Alexander N. , Leifeld Jens , Alewell Christine 
Published: February 2011

AbstractThe impact of fire on the nitrogen (N) cycle of natural ecosystems is arguable. Here we report and interpret an observation from boreal ecosystems in the Lena River basin, Sakha Republic (Yakutia), Russian Federation. Different types of permafrost soil (0–30 cm depth) were sampled along transects (60–150 m length) from the forest edge towards the centre of four separate thermokarst depressions under grassland. The average values of δ15N were remarkably similar within three transects, but differed systematically between them. Three findings point towards fire being the cause of the observed pattern. First, the spatial extent of systematic differences in soil δ15N coincides with the extent of typical fire scars in the region. Second, soil enrichment in 15N is larger in the proximity of settlements, where fire is generally more frequent than in more remote places. Third, there is a significant positive correlation between δ15N values and the ratio of black C to total N. These findings point towards fire having a marked impact on soil δ15N and, accordingly, on the N cycle of this cold and dry ecosystem. Copyright © 2011 John Wiley & Sons, Ltd.
Robust ℋ︁∞ sliding mode control for nonlinear stochastic systems with multiple data packet losses
Authors: Ma Lifeng , Wang Zidong , Bo Yuming , Guo Zhi 
Published: February 2011

SUMMARYIn this paper, an ℋ︁∞ sliding mode control (SMC) problem is studied for a class of discrete‐time nonlinear stochastic systems with multiple data packet losses. The phenomenon of data packet losses, which is assumed to occur in a random way, is taken into consideration in the process of data transmission through both the state‐feedback loop and the measurement output. The probability for the data packet loss for each individual state variable is governed by a corresponding individual random variable satisfying a certain probabilistic distribution over the interval [0 1]. The discrete‐time system considered is also subject to norm‐bounded parameter uncertainties and external nonlinear disturbances, which enter the system state equation in both matched and unmatched ways. A novel stochastic discrete‐time switching function is proposed to facilitate the sliding mode controller design. Sufficient conditions are derived by means of the linear matrix inequality (LMI) approach. It is shown that the system dynamics in the specified sliding surface is exponentially stable in the mean square with a prescribed ℋ︁∞ noise attenuation level if an LMI with an equality constraint is feasible. A discrete‐time SMC controller is designed capable of guaranteeing the discrete‐time sliding mode reaching condition of the specified sliding surface with probability 1. Finally, a simulation example is given to show the effectiveness of the proposed method. Copyright © 2011 John Wiley & Sons, Ltd.
Cryptanalysis of some conference schemes for mobile communications
Authors: He Daojing , Chen Chun , Ma Maode , Bu Jiajun 
Published: January 2011

ABSTRACTTo allow many users to hold a secure teleconference in mobile networks, a secure conference scheme with dynamic participation is necessary. However, designing a secure and efficient conference scheme is a difficult task because wireless networks are susceptible to attacks and wireless devices have limited resources. Recently, a lightweight and secure conference scheme has been suggested. Later, it has been found that this solution has security weaknesses and a modified version to overcome them has been presented. Compared with other conference schemes, these two schemes have many advantages. In this short paper, security study of these conference schemes in mobile networks has been performed with the following findings: (1) both the original scheme and the modified version are still vulnerable to our proposed impersonation attack; (2) they lack a mechanism to confirm the delivery of relevant messages, leading to protocol disruption. Therefore, these two schemes cannot be deployed for the real world applications without further development. Then, some efficient countermeasures are given for enhancing the security of both schemes. Further, the security properties of the improved protocol are formally validated by a model checking tool called AVISPA. Finally, several basic principles are suggested for the design of a secure conference scheme. Copyright © 2011 John Wiley & Sons, Ltd.
A self‐determination theory approach to understanding stress incursion and responses
Authors: Weinstein Netta , Ryan Richard M. 
Published: January 2011

AbstractGiven the high costs of stress for both mental and physical health, understanding of how stress is incurred and how it is coped with has both theoretical and clinical significance. Self‐determination theory (SDT), a broad framework for understanding motivation and personality, speaks to many issues concerning stress‐related phenomena. Research based on SDT suggests that both less stress incursion and better coping with demanding events are associated with greater autonomous functioning, higher mindfulness, more interest‐taking in internal events, and lifestyles focused on pursuing intrinsic over extrinsic goals, among other factors. These topics are discussed within the growing body of empirical research stemming from SDT and linkages are drawn with the larger literature on stress and coping. Copyright © 2011 John Wiley & Sons, Ltd.
On developing the microelectronics industry: A systems approach
Authors: Kawamura Kazuhiko , Silva Wainer Da Silveira E 
Published: February 2011

AbstractThis article presents a systems approach to microelectronics industry development. Rapid technological advances and price reductions in the microelectronics industry are changing everything from offices to factories. Many countries, including some developing countries like Brazil, are already aware of the importance of microelectronics technology and are developing strategies to compete in the world market. Developing a microelectronics industry is a complex process, technology constituting only one dimension. This paper uses the systems approach as an overall framework, and systematically develops a model for the microelectronics industry. The model then is applied to Brazil to illustrate how it can help policy makers develop better strategies for microelectronics industry development.