bluuebunny/crossref_metadata_2025 huggingface dataset:
Concordance of perimenstrual symptoms across two cycles
Authors: Shaver Joan Fowler , Woods Nancy Fugate
Published: February 2011

The prevalence of perimenstrual symptoms usually is based on reports for one menstrual cycle; the consistency of symptoms across cycles is ignored. The purpose of this investigation was to determine perimenstrual symptoms reported concordantly for two menstrual cycles in a group of 63 presumably healthy women reporting symptoms in health diaries over 2 months. There were only nine symptoms for each of the menstrual and premenstrual phases reported by the same woman across both cycles. Furthermore, concordance of perimenstrual symptom reporting across the two cycles was significant only for backache (κ = .636, p < .0001), headache (κ = .849, p < .001), and cramps (κ = .899, p < .0001) in the menstruum and for backache (κ = 0.123, p < .0001), cold sweats (κ = .500, p < .0001), fatigue (κ = .135, p < .0001), depression (κ = .268, p < .0002), and tension (κ = .320, p < .0001) in the premenstruum. Several symptoms showed high prevalence during the remainder of the cycle which might contribute to the lack of concordance. These data imply that prevalence estimates based on only one menstrual cycle may be inaccurate overall and inadequate as baseline or followup estimates by which to evaluate therapeutic intervention.
Mental status and functional health 4 days following relocation to a nursing home
Authors: Engle Veronica F.
Published: February 2011

Nurses frequently note changes in the health status of the aged following admission to a nursing home. The purpose of this study was to determine the stability of mental status and functional health over a 4‐day period immediately following relocation from hospital to nursing home. Participants (N = 55) over the age of 60 were chosen sequentially as admitted to a 120‐bed, long‐term care facility for rehabilitation or convalescence, and interviewed on Day 1 and Day 4 following admission. Level of consciousness, attention/concentration, orientation, memory, and higher cognitive function were evaluated by the Mental Status Examination, and six activities of daily living were evaluated by the Scaled Outcome Criteria. A matched pairs t‐test (p < .05) demonstrated no significant differences in mean scores between Day 1 and Day 4. Results indicated that these short‐term residents were stable in their mental status and functional health during the immediate period following relocation. Additional study is needed, with evaluation of the environment and its effect on participants' and expectation for length of stay.
Environmental support for autonomy in the institutionalized elderly
Authors: Ryden Muriel B.
Published: February 2011

The climate for autonomy in four urban proprietary nursing homes was investigated as part of a larger study of the relationship between perceived control and morale. Data from 113 residents, 137 caregivers, and 10 administrative personnel revealed that caregivers see themselves as the predominant decision makers. Although they prefer a slightly higher level of self‐determination for residents, only in one‐to‐one and solitary activities do they prefer giving residents the primary decision making role, possibly because they see most residents as not capable of making decisions. Residents saw themselves as having more control than did staff. Grooming and eating were identified by both groups as areas where residents had the least control. A substantial proportion of caregivers and administrative staff did not emphasize the availability of options to residents.
Use of the health belief model in determining frequency of breast self‐examination
Authors: Lee Champion Victoria
Published: February 2011

The purpose of this research was to identify the relationships of attitudes about breast self‐examination and breast cancer to the frequency of breast self‐examination. The health belief model was used as a theoretical base. Likert scales were developed for the independent variables of susceptibility, seriousness, benefit, barriers, and health motivation; the dependent variable was frequency of breast self‐examination. A convenience sample of 301 women was drawn from a large metropolitan city. Self‐administered questionnaires contained the developed scales, a measure of frequency of breast self‐examination, and demographic variables. Results supported the health belief model's prediction of frequency of breast self‐examination (R = .51; p ⩽ .01). In addition, the variables of seriousness, benefits, barriers, and health motivation discriminated groupings according to frequency of breast self‐examination. Results support the relationship of the health belief model variable to the behavior of breast self‐examination. Nursing implications are discussed.
Determinants of turnover among nursing department employees
Authors: Curry James P. , Wakefield Douglas S. , Price James L. , Mueller Charles W. , McCloskey Joanne C.
Published: February 2011

A causal model of turnover, or quitting, among hospital nursing department employees was evaluated. This model includes job satisfaction, organizational commitment, and intent to leave as intervening variables that mediate 13 determinants of turnover. The sample consisted of 841 female nursing department employees selected from five hospitals in a western state. Attitudinal and background data were obtained through a mail questionnaire survey, and turnover was monitored for 18 months following the survey. Intent to leave had a strong direct effect on turnover while kinship responsibility, job satisfaction, and organizational commitment had indirect effects on turnover through intent to leave. Task repetitiveness, autonomy, promotional opportunities, and fairness of rewards were important determinants of jobs satisfaction and thus provide a mechanism whereby hospital management may enhance commitment to the organization while reducing turnover.
Nursing workload, medical diagnosis related groups, and nursing diagnoses
Authors: Halloran Edward J.
Published: February 2011

Patient conditions associated with the relative amount of time nurses spent caring for patients were identified in this study. The patient conditions examined were: nursing condition using 37 nursing diagnoses, medical condition using diagnosis‐related groups (DRGs), and demographic characteristics of age, sex, and race. Nursing time was estimated using the Rush‐Medicus patient classification workload measurement tool. Data were gathered from checklists of nursing diagnoses and the discharge records of 2560 adult inpatients of an acute care community hospital. Using multiple regression analysis nursing condition explained twice the variation in daily nursing workload (52.4%) than medical condition (26.3%). The finding that nursing care time is predicted better by a patientapos;s nursing condition than by either medical condition or demographic characteristics indicates that nursing care is not physician prescribed.
Novel synthesis of nano‐calcium carbonate (CaCO3)/polystyrene (PS) core–shell nanoparticles by atomized microemulsion technique and its effect on properties of polypropylene (PP) composites
Authors: Mishra Satyendra , Chatterjee Aniruddha , Singh RajPal
Published: February 2011

Calcium carbonate (CaCO3)/polystyrene (PS) nanoparticles (<100 nm) with core–shell structure were synthesized by atomized microemulsion technique. The polymer chains were anchored onto the surface of nano‐CaCO3 through triethoxyvinyl silane (TEVS) as a coupling agent. Ammonium persulfate (APS), sodium dodecyl sulfate (SDS) and n‐pentanol were used as initiator, surfactant, and cosurfactant, respectively. Polymerization mechanism of core–shell latex particles was discussed. Encapsulation of nano‐CaCO3 by PS was confirmed by using transmission electron microscope (TEM). Grafting percentage of core–shell particles was investigated by Thermogravimetric Analyzer (TGA). Nano‐CaCO3/PS core–shell particles were characterized by Fourier transform infrared (FTIR) spectrophotometer and differential scanning calorimeter (DSC). The results of FTIR revealed existence of a strong interaction at the interface of nano‐CaCO3 particle and PS, which implies that the polymer chains were successfully grafted onto the surface of nano‐CaCO3 particle through the link of the coupling agent. In addition, TGA and DSC results indicated an enhancement of thermal stability of core–shell materials compared with the pure nano‐PS. Nano‐CaCO3/PS particles were blended with polypropylene (PP) matrix on Brabender Plastograph by melt process with different wt% of loading (i.e. 0.1–1 wt%). The interfacial adhesion between nano‐CaCO3 particles and PP matrix was significantly improved when the nano‐CaCO3 particles were grafted with PS, which led to increased thermal, rheological, and mechanical properties of (nano‐CaCO3/PS)/PP composites. Scanning electron microscope (SEM) and atomic force microscope (AFM) images showed a perfect dispersion of the nano‐CaCO3 particles in PP matrix. Copyright © 2011 John Wiley & Sons, Ltd.
β‐cyclodextrin‐based polymeric nano‐receptor: the self‐assembly of cyclodextrin‐appended comb‐copolymer
Authors: Kang Yan , Yuan Jinying , Yan Qiang , Zheng Liyao , Zhou Lilin
Published: February 2011

Well‐defined β‐cyclodextrin (β‐CD)‐appended biocompatible comb‐copolymer ethyl cellulose‐graft‐poly (ε‐caprolactone) (EC‐g‐PCL) was synthesized via the combination of ring‐opening polymerization (ROP) and click chemistry. The resulting products were characterized by 1H NMR, FT‐IR spectroscopy, and GPC. The synthesized comb‐copolymer could assemble to micelles, with the surface covered by β‐CD. The inclusion with ferrocene derivation was investigated by cyclic voltammetric (CV) experiments, which indicated the potential application of the micelles as nano‐receptors for molecule recognization and controlled drug release. Copyright © 2011 John Wiley & Sons, Ltd.
Preparation and properties of hollow silica tubes/bismaleimide/diallylbisphenol A composites with improved toughness, dielectric properties, and flame retardancy
Authors: Yao Wei , Gu Aijuan , Liang Guozheng , Zhuo Dongxian , Yuan Li
Published: February 2011

New high performance insulating composites based on hollow silica tubes (mHST) and bismaleimide/diallylbisphenol A (BDM/DBA) resin, which exhibit improved toughness, dielectric properties, and flame retardancy, were successfully developed. The effect of the amount of mHST on the properties of composites was systematically studied. Results show that the impact strength of the composite with 0.5 wt% mHST is about 2.2 times that of BDM/DBA resin. In addition, compared with BDM/DBA resin, the composites show lower and stable dielectric constant, better frequency stability of dielectric loss, significantly improved flame retardancy, and similarly outstanding thermal resistance. The reasons behind these attractive integrated properties are discussed from the view of structure–property relationship. Copyright © 2011 John Wiley & Sons, Ltd.
On the way to clean and safe electrospinning—green electrospinning: emulsion and suspension electrospinning
Authors: Agarwal Seema , Greiner Andreas
Published: February 2011

For the process of electrospinning, either water or organic solvents are used as solvents depending upon the solubility of the materials to be spun. For many applications, such as tissue engineering, biomedical, agricultural, etc., the toxicity of the organic solvent used could be highly critical. Besides this, the high viscosities of such polymer solutions even for low weight per cent (wt%) polymer solutions (generally for conventional electrospinning a maximum of 10–15 wt% polymer solution can be used) prevent high polymer concentrations and thereby reduces the productivity of the electrospinning process. This justifies the need for an approach which would alleviate concerns regarding safety, toxicology, and environmental problems, in addition, would also overcome the restrictions of too high polymer concentrations of polymer solutions. The answer could be suspension electrospinning. The term suspension electrospinning is referred to the electrospinning of aqueous dispersions (lattices) of water insoluble polymers and is defined in this article as Green Electrospinning. The present mini review highlights the efforts in this promising area of Emulsion and Suspension Electrospinning including their chances and limitations. Copyright © 2011 John Wiley & Sons, Ltd.
Super impact strength of blends prepared from regular HIPS and poly(butyl acrylate)‐block‐poly(styrene) obtained by RAFT polymerization
Authors: Enríquez‐Medrano Francisco J. , Hernández‐Valdez Martín , Maldonado‐Textle Hortensia , Lacroix‐Desmazes Patrick , Guerrero‐Santos Ramiro
Published: February 2011

S‐allyl‐4‐methyldithiobenzoate was synthesized and used as a chain transfer agent for the RAFT polymerization of butyl acrylate to produce a functionalized acrylic rubber. A solution of 8 wt% of this functionalized rubber was prepared in styrene and polymerized to generate a material called acrylic rubber‐modified polystyrene (AMP) constituted by well‐dispersed particles of poly(butyl acrylate)‐block‐poly(styrene) into a polystyrene matrix. Impact strength of injection‐molded samples of AMP was measured and compared with the general purpose polystyrene (GPPS) and the high impact polystyrene (HIPS). AMP itself showed an impact strength value similar to GPPS; however, when AMP was blended with conventional HIPS, the resulting material exhibited an improvement of 76–91% as compared to HIPS by itself, without affecting negatively tensile properties. Transmission electron microscopy analysis revealed both kinds of dispersed phases, i.e. the typical salami particles of polybutadiene coming from HIPS (size: 0.5–2 µ) and small particles from poly(butyl acrylate)‐block‐poly(styrene) (size: ∼50 nm). We clearly showed that such a bimodality of the particle size distribution caused the positive synergistic effect on impact strength. Copyright © 2011 John Wiley & Sons, Ltd.
Physicochemical characterization and drug release properties of PDMAEMA/OSA Semi‐IPN hydrogels with microporous structure
Authors: Gao Chunmei , Liu Mingzhu , Chen Jun , Chen Chen
Published: February 2011

A new poly(2‐(dimethylamino) ethyl methacrylate)/oxidized sodium alginate (PDMAEMA) semi‐interpenetrating network (Semi‐IPN) hydrogel with microporous structure was prepared by using PDMAEMA microgels as an additive during the polymerization/crosslinking process. The interior morphology characterized by scanning electron microscopy showed the Semi‐IPN hydrogels have different pore sizes by changing the amount of microgels. The hydrogels were also characterized by using Fourier transform infrared and DSC. The swelling behaviors of hydrogels indicated that the hydrogels have excellent pH and temperature sensitivity. Bovine serum albumin was entrapped in the hydrogels and the in vitro drug release profiles were established in different buffer solutions at various temperatures. The release behaviors of the model drug were dependent on the pore size of the hydrogels and environmental temperature/pH, which suggested that these materials have potential application as intelligent drug carriers. Copyright © 2011 John Wiley & Sons, Ltd.
Nuchal translucency measurement in fetuses with spinal muscular atrophy
Authors: Zadeh Neda , Hudgins Louanne , Norton Mary E.
Published: February 2011

Objective

Spinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative disorder with a high carrier frequency in the general population. The severity of this disorder indicates the importance of early prenatal detection. In medical literature, there are a few published case reports of enlarged nuchal translucency (NT) measurement in association with a diagnosis of SMA in the fetus. Our goal is to determine whether SMA in infants is associated with a history of an increased NT measurement during pregnancy.

Methods

Using contact information obtained through SMA family support groups, women who had recently given birth to infants affected with SMA were identified and queried about NT ultrasound results during the pregnancy. NT values were confirmed via ultrasound report to determine whether SMA was associated with a history of an enlarged NT measurement.

Results

Twelve SMA affected infants with confirmed NT results during the pregnancy were identified. All fetuses had normal NT values ranging from 0.7 to 2.4 mm.

Conclusion

In this series, SMA did not appear to be associated with an enlarged NT. Copyright © 2011 John Wiley & Sons, Ltd.
Polarization of photoluminescence excitation and emission spectra of silicon nanorods within single Si/SiO2 nanowires
Authors: Valenta Jan , Bruhn Benjamin , Linnros Jan
Published: February 2011

Polarization properties of individual silicon nanowires are studied using an optical micro‐spectroscopy setup equipped with a Fresnel rhomb to rotate the polarization of the exciting laser and the analyzer to characterize the polarization of emitted photoluminescence. The Si nanowire samples are prepared by electron‐beam lithography, plasma etching and oxidation. The fabricated wires are embedded in SiO2 and oriented parallel to the Si substrate. Due to the fluctuating wire diameter (around 5 nm) the very long wires (several tens of μm) are effectively divided into an array of quantum rods (prolate ellipsoids). These structures have strong photoluminescence under UV‐blue excitation at room temperature. The degree of photoluminescence linear polarization of both excitation and emission is very high, between 0.9‐1, and reveals relatively low fluctuations at different spots of the wires. Experimental results are compared with available theoretical models leading to the conclusion that the high polarization degree is mostly due to surface charges (dielectric confinement) with smaller contribution of quantum confinement effects (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Narrow photoluminescence peak from Ge(Si) islands embedded between tensile‐strained Si layers
Authors: Shaleev Mikhail , Novikov Alexey , Baydakova Nataliya , Yablonskiy Artem , Kuznetsov Oleg , Drozdov Yuriy , Lobanov Dmitriy , Krasilnik Zakhary
Published: February 2011

The influence of thickness of the strained Si layers, measurement temperature and optical pumping power on width of the photoluminescence line from Ge(Si) self‐assembled nanoislands grown on relaxed SiGe/Si(001) buffer layers and embedded between tensile‐stained Si layers was studied. This line appears due to the II‐type optical transition between the holes localized in islands and the electrons confined in tensile‐strained Si layers under and above the islands. The possibility of tuning the photoluminescence line width by changing the strained Si layer thicknesses under and above the islands is showed. The decrease of the photoluminescence line width from Ge(Si) islands down to values comparable with width of the PL line from InAs/GaAs quantum dots was achieved due to the quantum confinement of electrons in thin strained Si layers and taking into account of the higher diffusion‐induced smearing of strained Si layer above the islands. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Scanning confocal Raman spectroscopy of silicon phase distribution in individual Si nanowires
Authors: Nikolenko Andrii , Strelchuk Victor , Klimovskaya Alla , Lytvyn Peter , Valakh Mikhail , Pedchenko Yuriy , Voroschenko Andrii , Hourlier Djamila
Published: February 2011

Silicon nanowires were grown by gold enhanced CVD self‐assembly technique. In the Raman spectra of nanowires, along with phonon band of cubic diamond phase (Si I) at near 521 cm‐1, additional phonon bands at 516 and 496 cm‐1 related to hexagonal wurtzite phase (Si IV) were observed. Spatial distribution of intensities of these Raman bands around single nanowire reveals that both phases coexist along the wire length, even if with variable contributions. In addition, there is a strong alternating shift of Si I phonon band between the two ends of the nanowire (the one end is tipped with Au and the other end is the one that was connected to the substrate). Additionally, reversibility of Si IV phase transformation during laser heating at temperatures about 100 ºC was found. The intensity of Si IV band strongly depends on exciting power in the range of 0.05 to 1 mW/µm2. The observed phenomena are discussed in relation with peculiarities of nanowire growth. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Excitation of erbium ions in SiO2 with Si nanocrystals via virtual Auger process
Authors: Prokofiev A. A. , Moskalenko A. S. , Poddubny A. N. , Yassievich I. N.
Published: February 2011

Here we propose a possible mechanism of fast Er3+ ions excitation in SiO2 matrix with Si nanocrystals. We show that the presence of Si nanocrystals allows for non‐resonant optical pumping of erbium ions by virtual Auger transition, which is the second order process via an intermediate virtual state: the first step is the optical transition inside the Si NC, and the second one is Auger excitation of Er3+ ion accompanied by intraband transition of the confined carrier. This mechanism of excitation can take place when the energy of photon absorbed is larger than the sum of the confined electron‐hole ground state energy and the excitation energy of Er3+ ion. We have calculated the excitation cross‐section as a function of the excitation energy for erbium ions situated both inside and outside the NC.

We show that virtually all Er3+ ions inside NCs can be excited directly into the first excited state 4I13/2 (responsible for the 1.5 µm emission) by the laser pulse of duration 5–10 ns. The results obtained for ions located outside NCs demonstrate the efficiency of the virtual excitation Auger process for transition of erbium ions into the higher excited states. 1.5 µm PL appears in this case as a result of nonradiative relaxation of excited ions down to the 4I13/2 state. Correspondingly, the rise time of the 1.5 µm PL should be about several microseconds. The cross‐sections calculated demonstrate the efficiency of such Auger process (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimization of a label‐free biosensor vertically characterized based on a periodic lattice of high aspect ratio SU‐8 nano‐pillars with a simplified 2D theoretical model
Authors: Casquel R. , Holgado M. , Sanza F. J. , Laguna M. F. , Barrios C. A. , López‐Romero D. , Ortega F. J. , Bañuls M. J. , Puchades R. , Maquieira A.
Published: February 2011

We have recently demonstrated a biosensor based on a lattice of SU8 pillars on a 1 μm SiO2/Si wafer by measuring vertically reflectivity as a function of wavelength. The biodetection has been proven with the combination of Bovine Serum Albumin (BSA) protein and its antibody (antiBSA). A BSA layer is attached to the pillars; the biorecognition of antiBSA involves a shift in the reflectivity curve, related with the concentration of antiBSA. A detection limit in the order of 2 ng/ml is achieved for a rhombic lattice of pillars with a lattice parameter (a) of 800 nm, a height (h) of 420 nm and a diameter(d) of 200 nm. These results correlate with calculations using 3D‐finite difference time domain method. A 2D simplified model is proposed, consisting of a multilayer model where the pillars are turned into a 420 nm layer with an effective refractive index obtained by using Beam Propagation Method (BPM) algorithm. Results provided by this model are in good correlation with experimental data, reaching a reduction in time from one day to 15 minutes, giving a fast but accurate tool to optimize the design and maximizing sensitivity, and allows analyzing the influence of different variables (diameter, height and lattice parameter). Sensitivity is obtained for a variety of configurations, reaching a limit of detection under 1 ng/ml. Optimum design is not only chosen because of its sensitivity but also its feasibility, both from fabrication (limited by aspect ratio and proximity of the pillars) and fluidic point of view. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Tunable waveguides based on liquid crystal‐infiltrated silicon photonic crystals
Authors: Cos Joaquín , Ferré‐Borrull Josep , Pallarès Josep , Marsal Lluís F.
Published: February 2011

A methodology for the study of the practical implementation of tunable waveguides based on Silicon Photonic Crystals with liquid crystal‐infiltrated pores is presented. First, by using the FDTD method, the transmission properties of the waveguide depending on the liquid crystal optical axis orientation are studied. Then by means of the plane wave expansion method and taking into account the anisotropy of the photonic crystal components and considering adequate supercells, the transmission or rejection of the optical beam are explained. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photonic stop bands of two‐dimensional quasi‐random structures based on macroporous silicon
Authors: Rahman Mohammad Mahbubur , Ferré‐Borrull Josep , Pallarès Josep , Marsal Lluis F.
Published: February 2011

The existence of photonic stop bands in macroporous silicon with a quasi‐random structure transferred from nanoporous anodic alumina is studied. The quasi‐random structure consists of a periodic triangular arrangement broken into domains of random orientation and size. By means of Finite‐Difference Time‐Domain simulation, transmittance spectra of the structure are calculated which show that stop bands exist for the TE polarization in the same frequency range it exist for periodic photonic crystals. For TM polarization local minima of the transmittance are predicted by the calculations. A general trend of the transmittance to decrease with increasing frequency is observed. The comparison with the transmittance for random structures shows that such trend is due to incoherent scattering caused by the degree of randomness of the structure (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrically driven intentionally positioned single quantum dot
Authors: Mehta Minisha , Reuter Dirk , Wieck Andreas D. , Michaelis de Vasconcellos Steffen , Zrenner Artur , Meier Cedrik
Published: February 2011

Using a combined all‐ultra‐high‐vacuum process employing lateral patterning with focused ion beams and molecular beam epitaxy, site‐selective growth of single (In,Ga)As quantum dots is achieved. We have embedded such a layer of intentionally positioned quantum dots in the intrinsic region of a p‐i‐n junction so that the quantum dots can be driven electrically. In this contribution, we will present our results on the morphological properties of the ion‐beam modified surface on which the quantum dot nucleation occurs together with a characterization of the electrical and optoelectronic properties. We will demonstrate that a single, individual quantum dot can directly be electrically addressed. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Interaction of terahertz radiation with semiconductors
Authors: Koch Stephan W. , Golde Daniel , Kira Mackillo
Published: February 2011

The microscopic theory of the interaction of terahertz radiation with semiconductors is reviewed.

The theory is applied to analyze the intersubband terahertz response of optically excited semiconductor quantum wells (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Theoretical studies on the transport property of oligosilane with p‐n junction
Authors: Zhang Gui‐Ling , Yuan Hong‐Liang , Zhang Hui , Shang Yan , Sun Miao
Published: February 2011

The electron transport properties of a novel p‐n junction nanowire caused by boron‐doping and phosphorus‐doping are investigated using density functional theory combined with the nonequilibrium Green's functions formalism. A satisfying rectification is observed. This is a reasonable result after the analysis of the molecular‐projected self‐consistent Hamitonian (MPSH) states, transmission spectra, the frontier orbitals, and the dipole moments. In contrast, the undoped chain has no rectification character. In addition, a negative differential resistance behavior is also observed at V = 1.8 ∼ 2.2 V in the doped nanowire and it could be illustrated from the MPSH states and the transmission spectra. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Meaning of the wave function
Authors: Gao Shan
Published: February 2011

We investigate the meaning of the wave function by analyzing the mass and charge density distributions of a quantum system. According to protective measurement, a charged quantum system has effective mass and charge density distributing in space, proportional to the square of the absolute value of its wave function. In a realistic interpretation, the wave function of a quantum system can be taken as a description of either a physical field or the ergodic motion of a particle. The essential difference between a field and the ergodic motion of a particle lies in the property of simultaneity; a field exists throughout space simultaneously, whereas the ergodic motion of a particle exists throughout space in a time‐divided way. If the wave function is a physical field, then the mass and charge density will be distributed in space simultaneously for a charged quantum system, and thus, there will exist gravitational and electrostatic self‐interactions of its wave function. This not only violates the superposition principle of quantum mechanics but also contradicts experimental observations. Thus, the wave function cannot be a description of a physical field but a description of the ergodic motion of a particle. For the later, there is only a localized particle with mass and charge at every instant, and thus, there will not exist any self‐interaction for the wave function. It is further argued that the classical ergodic models, which assume continuous motion of particles, cannot be consistent with quantum mechanics. On the basis of negative result, we suggest that the wave function is a description of the quantum motion of particles, which is random and discontinuous in nature. On this interpretation, the square of the absolute value of the wave function not only gives the probability of the particle being found in certain locations but also gives the objective probability of the particle being there. We show that this new interpretation of the wave function provides a natural realistic alternative to the orthodox interpretation, and its implications for other realistic interpretations of quantum mechanics are also briefly discussed. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Direct MP2 molecular dynamics studies of H atom reaction with CD4 and CH4
Authors: Lu Peng , Kuang Xiao‐Yu , Li Hui‐Fang , Wang Huai‐Qian
Published: February 2011

The mechanism and dynamics of the H + CD4 → CD3 + HD (I) and H + CH4 → CH3 + H2 (II) reactions have been investigated by electronic structure methods. The minimum‐energy path and vibrational frequencies along the intrinsic reaction coordinate are calculated at MP2/cc‐pVDZ level. Energy distributions of the products are also obtained by the direct classical trajectory calculations at the MP2/ cc‐pVDZ level. It is found that most of the available energy appears as product translational energy, and very little of the available energy is partitioned into internal excitation of the HD (H2) product for reaction I (II), which is in agreement with the experimental evidence. The results indicate that the experimental results could be reproduced by the direct MP2 molecular dynamics calculations. The rotational state distributions of the products show the HD (H2) products are formed with lower rotational quantum numbers than the CD3 (CH3) products. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Finite element analysis in adjacent segment degeneration after lumbar fusion
Authors: Yan Jia‐Zhi , Qiu Gui‐Xing , Wu Zhi‐Hong , Wang Xue‐Song , Xing Ze‐Jun
Published: February 2011

Background

Adjacent segment degeneration (ASD) following lumbar fusion has been well documented in recent years. However, the pathogenesis of ASD is not clear. To investigate this issue, we established a finite element model of segments L2–L5, simulated a single‐segment posterior fixation in L3–L4 and investigated the stress variation and the effects of the instrumented lumbar posterior fixation on adjacent levels.

Methods

Models A, B and C of L2–L5 multisegment finite element intact models were established. In model A, segment L3–L4 was not fixed and was without disc degeneration in the adjacent segment (L2–L3, L4–L5); in model B there was posterior pedicle fixation in segment L3–L4 without disc degeneration in the adjacent segment (L2–L3, L4–L5); in model C there was posterior pedicle fixation in segment L3–L4 with a degenerated disc in the adjacent segment (L2–L3, L4–L5). Four levels of axial pressure, 0.3, 0.5, 1.0 and 2.0 MPa, were compared between each model of the stress variation on the discs of the adjacent segment (L2–L3, L4–L5).

Results

The maximum principal stress mean value of disc L2–L3 under four pressures in model A was determined. The statistical results showed that stress was not significant difference in disc L2–L3 between models A and B, but there was a significant difference in disc L2–L3 between models A and C and a significant difference between each group in disc L4–L5 under four pressure conditions.

Conclusions

The preoperative degeneration of the adjacent segment of the disc is a significant risk factor for ASD. Copyright © 2011 John Wiley & Sons, Ltd.
Assessment of joint symmetry in arthritis
Authors: Cresswell Lynne , Farewell Vern
Published: February 2011

We evaluate three methods for the assessment of symmetry in the joints affected by an arthritic disease. The first two methods, based on published methodology, are limited by their assumptions. We introduce a third method that enables a more comprehensive investigation. In common with previous methods, this method examines tabulations of observed data for evidence of symmetry. Expected values for the table cells are simulated under an assumption of independent joint disease, whilst allowing for differences between patients, and joint locations, in terms of their susceptibility to disease symptoms. Departures of observed from expected values are assessed via a Pearson‐type goodness‐of‐fit test and are examined for consistency with symmetry. We illustrate the three methods using data on the damage accrued in the hand joints of patients registered at the University of Toronto Psoriatic Arthritis clinic. Copyright © 2011 John Wiley & Sons, Ltd.
Modelling the rate of change in a longitudinal study with missing data, adjusting for contact attempts
Authors: Akacha Mouna , Hutton Jane L.
Published: February 2011

The Collaborative Ankle Support Trial (CAST) is a longitudinal trial of treatments for severe ankle sprains in which interest lies in the rate of improvement, the effectiveness of reminders and potentially informative missingness. A model is proposed for continuous longitudinal data with non‐ignorable or informative missingness, taking into account the nature of attempts made to contact initial non‐responders. The model combines a non‐linear mixed model for the outcome model with logistic regression models for the reminder processes. A sensitivity analysis is used to contrast this model with the traditional selection model, where we adjust for missingness by modelling the missingness process.

The conclusions that recovery is slower, and less satisfactory with age and more rapid with below knee cast than with a tubular bandage do not alter materially across all models investigated. The results also suggest that phone calls are most effective in retrieving questionnaires. Copyright © 2011 John Wiley & Sons, Ltd.
Generalized method for adaptive randomization in clinical trials
Authors: Russell D. , Hoare Z. S. J. , Whitaker Rh. , Whitaker C. J. , Russell I. T.
Published: February 2011

A flexible, generalized method of treatment allocation is proposed. The method uses a set of controlling parameters that enables the generic algorithm to produce a family of possible outcomes ranging from simple randomization to deterministic allocation. The method controls balance at stratum level, stratification level and overall without detriment to the predictability of the method. The paper lists the desirable characteristics of allocation methods and shows that the proposed method fulfils the majority and is easy to use in the clinical context, once the coding has been established. An explanation of the method for 2, 3 and 4 treatment group allocations is given. Simulations demonstrate the flexibility of the method. Copyright © 2011 John Wiley & Sons, Ltd.
Evaluation metrics for biostatistical and epidemiological collaborations
Authors: Rubio Doris McGartland , del Junco Deborah J. , Bhore Rafia , Lindsell Christopher J. , Oster Robert A. , Wittkowski Knut M. , Welty Leah J. , Li Yi‐Ju , DeMets Dave ,   the Biostatistics, Epidemiology, and Research Design (BERD) Key Function Committee of the Clinical and Translational Science Awards (CTSA) Consortium
Published: February 2011

Increasing demands for evidence‐based medicine and for the translation of biomedical research into individual and public health benefit have been accompanied by the proliferation of special units that offer expertise in biostatistics, epidemiology, and research design (BERD) within academic health centers. Objective metrics that can be used to evaluate, track, and improve the performance of these BERD units are critical to their successful establishment and sustainable future. To develop a set of reliable but versatile metrics that can be adapted easily to different environments and evolving needs, we consulted with members of BERD units from the consortium of academic health centers funded by the Clinical and Translational Science Award Program of the National Institutes of Health. Through a systematic process of consensus building and document drafting, we formulated metrics that covered the three identified domains of BERD practices: the development and maintenance of collaborations with clinical and translational science investigators, the application of BERD‐related methods to clinical and translational research, and the discovery of novel BERD‐related methodologies. In this article, we describe the set of metrics and advocate their use for evaluating BERD practices. The routine application, comparison of findings across diverse BERD units, and ongoing refinement of the metrics will identify trends, facilitate meaningful changes, and ultimately enhance the contribution of BERD activities to biomedical research. Copyright © 2011 John Wiley & Sons, Ltd.
Regression‐assisted deconvolution
Authors: McIntyre Julie , Stefanski Leonard A.
Published: February 2011

We present a semi‐parametric deconvolution estimator for the density function of a random variable biX that is measured with error, a common challenge in many epidemiological studies. Traditional deconvolution estimators rely only on assumptions about the distribution of X and the error in its measurement, and ignore information available in auxiliary variables. Our method assumes the availability of a covariate vector statistically related to X by a mean–variance function regression model, where regression errors are normally distributed and independent of the measurement errors. Simulations suggest that the estimator achieves a much lower integrated squared error than the observed‐data kernel density estimator when models are correctly specified and the assumption of normal regression errors is met. We illustrate the method using anthropometric measurements of newborns to estimate the density function of newborn length. Copyright © 2011 John Wiley & Sons, Ltd.
Changing paradigm for knowledge metaphors from dynamics to thermodynamics
Authors: Bratianu Constantin
Published: February 2011

The aim of the paper is to analyse dominant metaphors in knowledge management thinking, show their limitations by analysing their source domains, and then offer a better alternative. It has been demonstrated that metaphors play an important role in defining the concept of knowledge. In knowledge management important ideas incorporated into the SECI model and other extended knowledge dynamics models are based on the metaphors that have their source domain in Newtonian dynamics. These metaphors have limitations coming from some characteristics of the source domain that cannot be mapped onto the target domain, like the conservation law and linearity. The other limitation is that these metaphors hide the fact that knowledge and emotion go together. In order to integrate emotion into the knowledge concept we need a different set of four metaphors that have as a source domain the paradigm of thermodynamics. Copyright © 2011 John Wiley & Sons, Ltd.
Effects of UV weathering and a CeO2‐based coating layer on the mechanical and structural changes of wood/PVC composites
Authors: Pattamasattayasonthi Napat , Chaochanchaikul Kantima , Rosarpitak Vichai , Sombatsompop Narongrit
Published: February 2011

Composite samples (WPVCs) of poly(vinyl chloride) (PVC) and wood flour were prepared in the PVC:wood weight ratio of 1:1, and the mechanical and structural changes of the composites were assessed in terms of UV aging time and condensation temperature. Acrylic coating containing cerium dioxide as a UV absorber was used for moderation of the mechanical and structural changes of PVC in the WPVC composites. The experimental results indicated that the tensile and flexural properties of the composites monotonically decreased when the aging time was increased, the effect being more pronounced at high condensation temperatures. It was observed that the polyene and yellowness indexes of the WPVC composites increased with UV aging time. The hydrophilicity of the WPVC was quantified by contact angle results and found to increase with increasing UV aging because of hydrogen bonding between OH groups on the wood surfaces and water molecules. The acrylic coating containing CeO2 proposed in this work was sufficiently effective for maintaining the levels of hydrophilicity and mechanical properties of the WPVC composites. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers
Stabilization of low‐density polyethylene films containing metal stearates as photodegradants
Authors: Focke Walter W. , Mashele R. Puxley , Nhlapo Nontete S.
Published: February 2011

The effect of various stabilizer additives on Low‐Density Polyethylene films with a thickness of ca. 40 μm and containing metal stearates was studied. The films were subjected to accelerated aging in a QUV Weatherometer. The apparatus was fitted with A320 lamps and operated on a dry cycle at 63°C and an irradiance of 0.67 W/m2. A phosphite (Naugard P) and a phosphate (Alkanox 240P) antioxidant provided good stabilization against UV degradation accelerated by transition metal photocatalysts such as cobalt stearate. These compounds outperformed HALS‐based UV stabilizers and a metal deactivator (Irganox MD 1024) at the concentrations tested. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers
Chlorinated poly(vinyl chloride) stabilization by pentaerythritol/calcium‐zinc stearate mixtures: The fate of pentaerythritol
Authors: Liao Xin , He Bobing , Chen Xian
Published: February 2011

The stabilization effect of pentaerythritol (Pe) combined with calcium and zinc stearates (CaSt2/ZnSt2) on chlorinated poly(vinyl chloride) (CPVC) is investigated. Congo red and dynamic thermal stability data indicate that Pe alone has a mild stabilizing effect on the degradation of CPVC. Addition of mixed CaSt2/ZnSt2 to this system leads to a significant improvement in stability. Thermogravimetric studies indicate that premature weight loss, not observed with either Pe alone or with CaSt2/ZnSt2, is observed when the combined Pe/CaSt2/ZnSt2 systems are employed to stabilize CPVC. Fourier transform infrared (FTIR) spectroscopy and electrospray ionization mass spectrometry (ESIMS) both indicate that condensation (oligomerization) and chlorination of Pe occur when Pe and Pe/CaSt2/ZnSt2 systems are employed to stabilize CPVC. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers
Miscibility and thermal and mechanical properties of melt‐mixed poly(lactic acid)/poly(trimethylene terephthalate)/(methyl methacrylate)‐butadiene‐styrene copolymer blends
Authors: Lin San‐Wai , Cheng Yao‐Yi
Published: February 2011

This study examined the miscibility and mechanical properties of melt‐mixed poly(lactic acid) (PLA), poly (trimethylene terephthalate) (PTT), and PLA/PTT blend with 5–10 phr of methyl methacrylate‐butadiene‐styrene copolymer (MBS). The isothermal crystallization kinetics of the PTT blends were analyzed by using the Avrami equation. The Differential Scanning Calorimetry (DSC) and scanning electron microscope results indicated that the miscibility of the PLA/PTT blends was improved by adding 5–10 phr of MBS. Although PLA, with the addition of 10 phr of MBS, had lower tensile strength at yield and higher breaking elongation and impact strength than pure PLA, no improvement in these mechanical properties could be observed in PLA/PTT blends. This result is explained by assuming that the crystallization of PTT at the interface favors the disentanglement of MBS from the PTT domain. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers
Kinetics of water absorption and thermal properties of poly(lactic acid)/organomontmorillonite/poly(ethylene glycol) nanocomposites
Authors: Leu Ying Ying , Chow Wen Shyang
Published: February 2011

Poly(lactic acid) (PLA)/organomontmorillonite (OMMT) nanocomposites were prepared by a melt intercalation technique. The effects of OMMT and poly(ethylene glycol) (PEG) on the thermal properties and water absorption behavior of PLA were investigated. The melting temperature and degree of crystallinity were comparable for the PLA and its nanocomposites. The glass transition temperature and crystallization temperature of PLA were decreased by the addition of PEG. X‐ray diffraction results revealed the formation of PLA nanocomposites, as the OMMT was partly intercalated and partly exfoliated. The maximum moisture absorption of PLA was increased in the presence of PEG and the diffusivity of the PLA nanocomposites decreased with increasing concentrations of PEG. However, the activation energy of the nanocomposites increased as the loading of PEG increased. These results indicated that the incorporation of OMMT and PEG enhanced the water‐barrier properties of the PLA. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers
Heat transfer in a micropolar fluid flow past a permeable continuous moving surface
Authors: El‐Kabeir S.M.M. , Rashad A.M. , Gorla R.S.R.
Published: February 2011

A boundary layer analysis is presented for the fluid flow and heat transfer characteristics of an incompressible micropolar fluid flowing over a permeable continuous moving surface with uniform surface heat flux conditions. Two cases are considered, one corresponding to a plane surface moving in parallel with a free stream and the other, a surface moving in the opposite direction to the free stream. The resulting system of non‐linear ordinary differential equations is solved numerically using fourth‐order Runge‐Kutta method with shooting techniques. Numerical results are obtained for velocity, angular velocity, and temperature distributions, as well as the friction factor, local Nusselt number and wall couple stress for prescribed values of the velocity ratio parameter, suction/injection parameter, and micropolar parameter. The obtained results are presented graphically and in tabular form and the physical aspects of the problem are discussed for both parallel and reverse moving plates relative to the free stream direction.