bluuebunny/crossref_metadata_2025 huggingface dataset:
High Thermal Conductive Si3N4 Particle Filled Epoxy Composites With a Novel Structure
Authors: He Hong , Fu Renli , Han Yanchun , Shen Yuan , Wang Deliu
Published: December 2007

Traditionally, large quantities of ceramic fillers are added to polymers in order to obtain high thermally conductive polymer composites, which are used for electronic encapsulants. However, that is not cost effective enough. In this study, Si3N4 particle filled epoxy composite with a novel structure was fabricated by a processing method and structure design. Epoxy resin used in particle form was obtained by premixing and crushing. Different particle sizes were selected by sieving. High thermal conductivity was achieved at relative low volume fraction of the filler. The microstructure of the composites indicates that a continuous network is formed by the filler, which mainly completes the heat conduction. Thermal conductivity of the composites increases as the filler content increases, and the samples exhibit a highest thermal conductivity of 1.8W∕mK at 30% volume fraction of the filler in the composites using epoxy particles of 2mm. The composites show low dielectric constant and low dielectric loss.
Effort–reward imbalance and incidence of low back and neck injuries in San Francisco transit operators
Authors: Rugulies R , Krause N
Published: December 2007

Objectives:

Effort–reward imbalance (ERI) has been associated with musculoskeletal disorders in cross-sectional and case–control studies, but no longitudinal studies have been published yet. The effect of ERI on the incidence of compensated low back and neck injuries was examined in a 7.5-year follow-up study among 1179 San Francisco transit operators.

Methods:

Data from medical examination and a survey on working conditions and health were linked to administrative workers’ compensation databases. HRs for first low back and first neck injury were calculated with multivariate Cox regression models. Additional analyses accounted for severity of injury based on medical diagnosis.

Results:

A 1 SD increase in ERI was associated with compensated low back (HR 1.13, 95% CI 1.02 to 1.26) and neck injuries (HR 1.14, 95% CI 1.02 to 1.27) after adjusting for gender, age, height, weight, years of professional driving, weekly driving hours, vehicle type, ergonomic problems, pain at baseline and job strain. The highest quartile of ERI showed an HR of 1.32 (95% CI 0.94 to 1.86) for low back injuries and an HR of 1.66 (95% CI 1.16 to 2.38) for neck injuries after adjustment for all covariates. The associations between ERI and low back injury were stronger for more severe injuries (HR 1.23, 95% CI 1.03 to 1.46 for a 1 SD increase in ERI) than for less severe injuries (HR 1.11, 95% CI 0.96 to 1.28). For neck injuries, stronger relationships were found for less severe injuries (HR 1.15, 95% CI 1.02 to 1.29) than for more severe injuries (HR 1.10, 95% CI 0.86 to 1.41).

Conclusions:

ERI is associated with low back and neck injuries in San Francisco transit operators independently of individual worker characteristics, physical workload, ergonomic problems, baseline pain and job strain. Effect sizes differ by injury severity.
How common is repetitive strain injury?
Authors: Palmer K T , Reading I , Calnan M , Coggon D
Published: December 2007

Objective:

Statistics from Labour Force Surveys are widely quoted as evidence for the scale of occupational illness in Europe. However, occupational attribution depends on whether participants believe their health problem is caused or aggravated by work, and personal beliefs may be unreliable. The authors assessed the potential for error for work-associated arm pain.

Methods:

A questionnaire was emailed to working-aged adults, randomly chosen from five British general practices. They were asked about: occupational activities; mental health; self-rated health; arm pain; and beliefs about its causation. Those in work (n = 1769) were asked about activities likely to cause arm pain, from which the authors derived a variable for exposure to any “arm-straining” occupational activity. The authors estimated the relative risk (RR) from arm-straining activity, using a modified Cox model, and derived the population attributable fraction (PAF). They compared the proportion of arm pain cases reporting their symptom as caused or made worse by work with the calculated PAF, overall and for subsets defined by demographic and other characteristics.

Results:

Arm pain in the past year was more common in the 1143 subjects who reported exposure to arm-straining occupational activity (RR 1.2, 95% CI 1.1 to 1.5). In the study sample as a whole, 53.9% of 817 cases reported their arm pain as work-associated, whereas the PAF for arm-straining occupational activity was only 13.9%. The ratio of cases reported as work-related to the calculated attributable number was substantially higher below 50 years (5.4) than at older ages (3.0) and higher in those with worse self-rated and mental health.

Conclusions:

Counting people with arm pain which they believe to be work-related can overestimate the number of cases attributable to work substantially. This casts doubt on the validity of a major source of information used by European governments to evaluate their occupational health strategies.
Evaluation of the need for endoscopy to identify low-risk patients presenting with an acute upper gastrointestinal bleed suitable for early discharge
Authors: Robins G G , Sarwar M S , Armstrong M , Denyer M E , Bush S , Hassan T , Everett S M
Published: December 2007

Aims

To audit the safety of differing protocol-driven early-discharge policies, from two sites, for low-risk acute upper gastrointestinal (GI) bleeding and determine if default early (<24 h) in-patient endoscopy is necessary.

Methods

All patients with low-risk acute upper GI bleeding presenting to two separate hospital sites in Leeds from August 2002 to March 2005 were identified. Both hospitals operate nurse-led process-driven protocols for discharge within 24 h, but only one includes default endoscopy. Relevant information was obtained from patients' notes, patient administration systems, discharge letters and endoscopy records.

Results

120 patients were admitted to site A and 74 to site B. Median length of stay on the clinical decisions unit was 12.6 h at site A and 9.4 h at site B (p = 0.045). Oesophagogastroduodenoscopy was performed on 89/120 (74%) patients at site A compared with only 7/74 (9%) at site B (p<0.001). Six of 120 (5%) patients from site A were admitted to hospital for further observation compared with 6/74 (8%) from site B (p = 0.38). Of the remaining patients, all were discharged within 24 h, and 8/114 (7%) at site A vs 17/68 (25%) at site B were given hospital clinic follow-up (p<0.001). None of the 194 patients had further bleeding or complications within 30 days.

Conclusions

Patients admitted with a low-risk acute upper GI bleeding can be managed safely by a nurse-led process-driven protocol, based on readily available clinical and laboratory variables, with early discharge <24 h. Avoiding in-patient endoscopy appears to be safe but at the price of greater clinic follow-up.
ASSESSMENT OF COMPUTATIONAL MODELS FOR LAMINATED COMPOSITE PLATES
Authors: SUBHA K. , SHASHIDHARAN  , SAVITHRI S. , PRAKASH V. SYAM
Published: December 2007

In this paper, results of the stress analysis of composite laminates subjected to mechanical load based on different higher order shear deformation theories are presented. Among the many equivalent single layer theories (ESL), the third-order shear deformation theory of Reddy is the most widely accepted model in the study of laminates. This model cannot represent shear stress continuity at the interfaces and zigzag nature of the displacement field. To improve the accuracy of transverse shear stress prediction, layer wise theories have proved to be very promising techniques. In all these theories, zero transverse shear stress boundary conditions at the top and the bottom of the plate are imposed. In many engineering applications, this requirement is not valid when the plate is subjected to shear traction parallel to the surface. To account for this, a displacement model which releases the zero transverse shear stress boundary condition is taken. The unconstrained third-order shear deformation theory (UTSDT) is useful where the boundary layer shear stress is significant. Navier solutions for bending and stress analysis of cross ply laminates are presented using layer wise model, unconstrained third-order shear deformation model and Reddy's ESL model, and compared with 3D elasticity solutions.
Vertebrate osmoregulation: a student laboratory exercise using teleost fish
Authors: Boily P. , Rees B. B. , Williamson L. A. C.
Published: December 2007

Here, we describe a laboratory experiment as part of an upper-level vertebrate physiology course for biology majors to investigate the physiological response of vertebrates to osmoregulatory challenges. The experiment involves measuring plasma osmolality and Na+-K+-ATPase activity in gill tissue of teleost fish acclimated to water of differing salinity. We describe results obtained using the widely available goldfish ( Carassius auratus) and a common baitfish, the Gulf killifish ( Fundulus grandis). The procedures described are generally applicable to other fish species, and they provide an alternative to the experimental use of humans or other mammalian species to investigate osmoregulation mechanisms. In addition to reenforcing the conceptual material covered in lecture, this laboratory exercise trains students in a wide range of laboratory and analytical skills, such as calculating and performing dilutions, pipetting, tissue sampling and homogenizing, preparing standard curves, conducting enzymatic assays, and analyzing and interpreting results. Typical student results are presented and discussed, as are common experimental and conceptual mistakes made by students.
Conceptual Assessment in the Biological Sciences: a National Science Foundation-sponsored workshop
Authors: Michael Joel
Published: December 2007

Twenty-one biology teachers from a variety of disciplines (genetics, ecology, physiology, biochemistry, etc.) met at the University of Colorado to begin discussions about approaches to assessing students' conceptual understanding of biology. We considered what is meant by a “concept” in biology, what the important biological concepts might be, and how to go about developing assessment items about these concepts. We also began the task of creating a community of biologists interested in facilitating meaningful learning in biology. Input from the physiology education community is essential in the process of developing conceptual assessments for physiology.
Palmitate action to inhibit glycogen synthase and stimulate protein phosphatase 2A increases with risk factors for type 2 diabetes
Authors: Mott David M. , Stone Karen , Gessel Mary C. , Bunt Joy C. , Bogardus Clifton
Published: December 2007

Recent studies have suggested that abnormal regulation of protein phosphatase 2A (PP2A) is associated with Type 2 diabetes in rodent and human tissues. Results with cultured mouse myotubes support a mechanism for palmitate activation of PP2A, leading to activation of glycogen synthase kinase 3. Phosphorylation and inactivation of glycogen synthase by glycogen synthase kinase 3 could be the mechanism for long-chain fatty acid inhibition of insulin-mediated carbohydrate storage in insulin-resistant subjects. Here, we test the effects of palmitic acid on cultured muscle glycogen synthase and PP2A activities. Palmitate inhibition of glycogen synthase fractional activity is increased in subjects with high body mass index compared with subjects with lower body mass index ( r = −0.43, P = 0.03). Palmitate action on PP2A varies from inhibition in subjects with decreased 2-h plasma glucose concentration to activation in subjects with increased 2-h plasma glucose concentration ( r = 0.45, P < 0.03) during oral glucose tolerance tests. The results do not show an association between palmitate effects on PP2A and glycogen synthase fractional activity. We conclude that subjects at risk for Type 2 diabetes have intrinsic differences in palmitate regulation of at least two enzymes (PP2A and glycogen synthase), contributing to abnormal insulin regulation of glucose metabolism.
Effect of short-term intralipid infusion on the immune response during low-dose endotoxemia in humans
Authors: Krogh-Madsen Rikke , Plomgaard Peter , Akerstrom Thorbjorn , Møller Kirsten , Schmitz Ole , Pedersen Bente Klarlund
Published: December 2007

Novel anti-inflammatory effects of insulin have recently been described, and insulin therapy to maintain euglycemia suppresses the plasma levels of free fatty acids (FFA) and increases the survival of critically ill patients. We aimed to explore the effect of short-term high levels of plasma FFA on the inflammatory response to a low dose of endotoxin. Fourteen healthy male volunteers underwent the following two trials in a randomized crossover design: 1) continuous infusion of 20% Intralipid [0.7 ml·kg−1·h−1(1.54 g/kg)] for 11 h, and 2) infusion of isotonic saline for 11 h (control). In each trial, heparin was given to activate lipoprotein lipase, and an intravenous bolus of endotoxin (0.1 ng/kg) was given after 6 h of Intralipid/saline infusion. Blood samples and muscle and fat biopsies were obtained before the Intralipid/saline infusion and before as well as after infusion of an endotoxin bolus. Plasma levels of FFA, triglycerides, and glycerol were markedly increased during the Intralipid infusion. Endotoxin exposure induced an increase in plasma levels of TNF-α, IL-6, and neutrophils and further stimulated gene expression of TNF-α and IL-6 in both skeletal muscle and adipose tissue. The systemic inflammatory response to endotoxin was significantly pronounced during Intralipid infusion. Short-term hyperlipidemia enhances the inflammatory response to endotoxin, and skeletal muscle and adipose tissue are capable of producing essential inflammatory mediators after endotoxin stimulation.
Gene expression in mouse brain following chronic hypoxia: role of sarcospan in glial cell death
Authors: Zhou Dan , Wang Jiyi , Zapala Matthew A. , Xue Jin , Schork Nicholas J. , Haddad Gabriel G.
Published: December 2007

Hypoxia is a hallmark of respiratory, neurological, or hematological diseases as well as life at high altitude. For example, chronic constant hypoxia (CCH) occurs in chronic lung diseases or at high altitude, whereas chronic intermittent hypoxia (CIH) occurs in diseases such as sleep apnea or sickle cell disease. Despite the fact that such conditions are frequent, the cellular and molecular mechanisms underlying the effect of hypoxia, whether constant or intermittent, are not well understood. In this study, we first determined the effect of CCH and CIH on global gene expression in different regions of mouse brain using microarrays and then investigated the biological role of genes of interest. We found that: 1) in the cortical region, the expression level of 80 genes was significantly altered by CIH (16 up- and 64 downregulated), and this number increased to 137 genes following CCH (34 up- and 103 downregulated); 2) a similar number of gene alterations was identified in the hippocampal area, and the majority of the changes in this region were upregulations; 3) two genes (Sspn and Ttc27) were downregulated in both brain regions and following both treatments; and 4) RNA interference-mediated knockdown of Sspn increased cell death in hypoxia in a cell culture system. We conclude that CIH or CCH induced significant and distinguishable alterations in gene expression in cortex and hippocampus and that Sspn seems to play a critical role in inducing cell death under hypoxic conditions.
A Syringe Simulation of Biological Controls for Quality Assessment of Prospective Lung Volume Measurements
Authors: Ninaber Maarten K. , Schot Robert , Fregonese Laura , Stolk Jan
Published: December 2007

Background: At present a syringe is being used for calibration of lung function devices, but biological controls are used to detect prospectively the variability and reproducibility of lung volumes measured by spirometers. Laboratory personnel is often used as biological control and therefore the cost for these measurements is substantial and may be reduced by replacement of a syringe procedure to increase the capacity of the laboratory to measure more patients. Objectives: To develop a mechanical syringe procedure for identification of instrument problems. Methods: A commercial 3-liter precision syringe is used to simulate breathing maneuvers (inspiratory vital capacity, functional residual capacity, residual volume and total lung capacity) on a spirometer. Three healthy males representing biological controls performed spirometry, maximum expiratory flow volume and helium dilution forced residual capacity at bimonthly intervals for 3 years. Confidence intervals and interval widths are calculated for each parameter. Levene’s test for equality of variances was used to test for significance between standard deviations. Results: The interval width of inspiratory vital capacity, functional residual capacity, total lung capacity and residual volume of repeated measurements obtained from the syringe was significantly narrower than those of biological controls. In addition, almost all standard deviations from lung volumes obtained from the syringe were smaller and significantly different from those of the biological control. Conclusion: Our syringe procedure may replace biological controls for detection of variability of lung volumes. This will result in cost reduction and improve quality assessment of lung function devices.
Application of the Bimodal Meso/Macroporous Composite Synthesized from MCM-41 Sol
Authors: Shin Chang-Kyo , Kawthekar Rahul B. , Kim Geon-Joong
Published: December 2007

A route to synthesize porous materials with a bimodal macro/mesoscopic pore system has been investigated in this work. Polystyrene with sub-micrometer size was used as a template in the synthesis. The resulting mesoporous silica wall replicated inversely the morphology of polystyrene
template and had highly ordered three-dimensional arrays of macro pores. Large and moldable meso/macro porous silica monoliths could be obtained in centimeter scale by using monodispersed polystyrene beads and MCM-41 sol solutions. These bimodal structured porous silicates have been used as
supports for asymmetric kinetic resolution of racemic epoxides to synthesize optically pure epoxide.
Silver Nanoparticles Incorporated Electrospun Silk Fibers
Authors: Kang Minsung , Jung Rira , Kim Hun-Sik , Youk Ji Ho , Jin Hyoung-Joon
Published: December 2007

We present a simple and mass-producible method of incorporating silver nanoparticles on the surface of electrospun silk non-woven membranes for the fabrication of antimicrobial wound dressings. Nanofibrous silk membranes with fiber diameters of 460±40 nm were electrospun from
an aqueous Bombyx mori fibroin solution. The electrospun membranes incorporating silver nanoparticles were prepared by dipping the membranes in aqueous silver nitrate (AgNO3) solution (0.5 or 1.0 wt%) followed by photoreduction. Field emission scanning and transmission electron
microscopy showed that silver nanoparticles were generated on the electrospun silk fibroin nanofibers as well as inside them. The interaction between the silver nanoparticles and amide groups in the silk fibroin molecules was characterized using X-rayphotoelectron spectroscopy.
Time-Dependent X-ray Absorption Spectroscopic (XAS) Study on the Transformation of Zinc Basic Salt into Bis(N-oxopyridine-2-thionato) Zinc (II)
Authors: Paek Seung-Min , Jo Won-Young , Park Man , Choy Jin-Ho
Published: December 2007

Solid transchelation reaction was established for the synthesis of bis(N-oxopyridine-2-thionato) zinc (II), commonly known as zinc pyrithione (ZPT), to control particle size using zinc basic salt (ZBS) and aqueous sodium pyrithione solution. Distinguished from ZPT particles prepared
by usual precipitation reaction, the obtained ZPT nanoparticles exhibited very narrow size distribution. X-ray absorption spectroscopy (XAS) at Zn K-edge was systematically examined to elucidate time-dependent local structural evolution during solid transchelation reaction. X-ray absorption
near edge structure (XANES) analysis clearly revealed that local environment around zinc atoms transformed into pentahedron as reaction proceeded. Based on quantitative X-ray diffraction and XANES analysis, we made structural models. Theoretical XAS spectrum calculated with FEFF code could
reproduce experimental one, suggesting that XAS analysis could be very powerful tool to probe phase transformation. Furthermore, according to extended X-ray absorption fine structure (EXAFS) fitting results, Zn-O distance in reaction products gradually increased from 1.96 to 2.07 Å,
suggesting that zinc atoms bounded with oxygen ones in ZBS were transchelated with pyrithione ligands. This study could be a strong evidence for the usefulness of XAS to study time-dependent structural transformation of nanocrystalline materials.
Microspherical Poly(methyl methacrylate)/Multiwalled Carbon Nanotube Composites Prepared via In Situ Dispersion Polymerization
Authors: Kim Hun-Sik , Myung Seung Jun , Jung Rira , Jin Hyoung-Joon
Published: December 2007

In this study, microspherical poly(methyl methacrylate)/multi-walled carbon nanotube (PMMA/MWCNT) composites were directly prepared by in situ dispersion polymerization using poly (N-vinylpyrrolidone) in methanol media. PMMA/MWCNT microspheres having a diameter of 2.6∼3.9
μm and a molecular weight of 58,000∼65,000 g/mol with a 15.7∼19.5% coefficient of variation (Cv) were synthesized. The morphology of the synthesized composite was investigated using scanning electron microscopy and transmission electron microscopy. The experimental results
demonstrated that MWCNTs are well dispersed and embedded in the final PMMA/MWCNT microspheres. The prepared PMMA/MWCNT microspheres were investigated in terms of their capacity to serve as an electrorheological (ER) materials.
Effect of Metal Powder Packing on the Conductivity of Nanometal Ink
Authors: Kim Nam-Soo , Amert Anthony K. , Woessner Stephen M. , Decker Shawn , Kang Sun-Mee , Han Kenneth N.
Published: December 2007

The power of nanotechnology is realized in its application in numerous areas. One such area is undoubtedly the use of metallic nanoparticles as a direct write application. An effort in this area has resulted in a conductive ink whose conductivity approaches 60–70%that of the bulk
copper. Such an ink has been developed by reducing silver, gold, and copper nano-sized powders by a wet method and followed by a heat treatment at less than 400 °C. The conductivity of the resulting ink product was found to be very much affected by how various sizes of metal powders are
packed when particles were dried and packed on various substrates. The effect of packing and various kinds of metal powders on the eventual conductivity of the final product of the ink has been described and discussed in this paper.
Hysteresis in a Carbon Nanotube Based Electroactive Polymer Microfiber Actuator: Numerical Modeling
Authors: Sohn Kiwon , Shin Su Ryon , Park Sang Jun , Kim Seon Jeong , Yi Byung-Ju , Han Seog Young , Kim Sun I.
Published: December 2007

Hysteretic behavior is an important consideration for smart electroactive polymer actuators in a wide variety of nano/micro-scale applications. We prepared an electroactive polymer actuator in the form of a microfiber, based on single-wall carbon nanotubes and polyaniline, and investigated
the hysteretic characteristics of the actuator under electrical potential switching in a basic electrolyte solution. For actuation experiments, we measured the variation of the length of the carbon-nanotube-based electroactive polymer actuator, using an Aurora Scientific Inc. 300B Series muscle
lever arm system, while electrical potentials ranging from 0.2 V to 0.65 V were applied. Based on the classical Preisach hysteresis model, we presented and validated a numerical model that described the hysteretic behavior of the carbon-nanotube-based electroactive polymer actuator. Inverse
hysteretic behavior was also simulated using the model to demonstrate its capability to predict an input from a desired output. This numerical model of hysteresis could be an effective approach to micro-scale control of carbon-nanotube-based electroactive polymer actuators in potential applications.
Nanostructured Bulk Copper Fabricated by Accumulative Roll Bonding
Authors: Takata Naoki , Lee Seong-Hee , Lim Cha-Yong , Kim Sang-Shik , Tsuji Nobuhiro
Published: December 2007

In this study, we tried to fabricate the nanostructured bulk copper alloys by a severe plastic deformation process. The sheets of copper alloys (OFC, PMC90, and DLP) were heavily deformed to an equivalent strain of 6.4 by the accumulative roll-bonding (ARB) process. The microstructure
and the mechanical property of the fabricated specimens were systematically investigated. The microstructure was finely subdivided with increasing the equivalent strain by the ARB process. The severely deformed copper alloys exhibited the ultrafine lamellar boundary structure where the mean
lamella spacing was about 200 nm. The strength significantly increased with decreasing the lamella spacing in the ARB processed copper alloys. Especially, the tensile strength of the DLP alloys ARB processed by 8 cycles (the equivalent strain of 6.4) reached to 520 MPa, which was about three
times higher than that of same materials with conventional grain size of 10–100 μm. On the other hand, the total elongation greatly dropped only by 1 ARB cycle corresponding to an equivalent strain of 0.8, which was around 3%. However, the total elongation increased again with
increasing the number of the ARB cycle, and it reached to 10% after 8 cycles. The recovery of the total elongation could be recognized in all studied copper alloys. The obtained stress–strain curves showed that the improvement of the total elongation was caused by the increase in the
post-uniform elongation. It can be concluded that the nanostructured copper alloys sheets having high strength without a large loss of ductility could be fabricated by the ARB process.
Effect of Copper Doping on the Crystal Structure and Morphology of 1D Nanostructured Manganese Oxides
Authors: Lee Sun Hee , Park Dae Hoon , Hwang Seong-Ju , Choy Jin-Ho
Published: December 2007

We have tried to control the aspect ratio and physicochemical properties of 1D nanostructured manganese oxides through copper doping. Copper-doped manganese oxide nanostructures have been synthesized by one-pot hydrothermal treatment for the mixed solution of permanganate anions and
copper cations. According to powder X-ray diffraction and electron microscopic analyses, all the present materials commonly crystallize with α-MnO2-type structure but their aspect ratio decreases significantly with increasing the content of copper. Such a variation
of crystallite dimension is attributable to the limitation of crystal growth by the incorporation of copper ions. X-ray absorption spectroscopic studies at Mn K- and Cu K-edges clearly demonstrate that the average oxidation state of manganese ions is increased by the substitution of divalent
copper ions. Electrochemical measurements reveal the improvement of the electrode performance of nanostructured manganate upon copper doping, which can be interpreted as a result of the decrease of aspect ratio and the increase of Mn valence state. From the present experimental findings, it
becomes certain that the present Cu doping method can provide an effective way of controlling the crystal dimension and electrochemical property of 1D nanostructured manganese oxide.
Nanocrystalline Particle Coatings on α-Alumina Powders by a Carbonate Precipitation and Thermal-Assisted Combustion Route
Authors: Kim Sang Woo , Jung Young Mi
Published: December 2007

We have suggested ultrafine particle coating processes for preparing nanocrystalline particle coated α-alumina powders by a carbonate precipitation and thermal-assisted combustion route, which is environmentally friendly. The nanometric ammonium aluminum carbonate hydroxide
(AACH) as a precursor for coating of alumina was produced from precipitation reaction of ammonium aluminum sulfate and ammonium hydrogen carbonate. The synthetic crystalline size and morphology were greatly dependent on pH and temperature. By adding ammonium aluminum sulfate solution dispersed
the α-alumina core particle in the ammonium hydrogen carbonate aqueous solution, nanometric AACHwith a size of 5 nm was tightly bonded and uniformly coated on the core powder due to formation of surface complexes by the adsorption of carbonates, hydroxyl and ammonia groups on
the surface of aluminum oxide. The synthetic precursor rapidly converted to amorphous- and γ-alumina phase without significant change in the morphological features through decomposition of surface complexes and thermal-assisted phase transformation. As a result, the nanocrystalline
polymorphic particle coated α-alumina core powders with highly uniform distribution were prepared from the route of carbonate precipitation and thermal-assisted combustion.
Dry Sol–Gel Polycondensation of Hydrosilanes to Organosilicas Catalyzed by Colloidal Nickel Nanoparticles
Authors: Kim Bo-Hye , Cho Myong-Shik , Kim So-Yeun , Kim You-Jeong , Woo Hee-Gweon , Kim Do-Heyoung , Sohn Honglae , Li Andhong
Published: December 2007

The dry sol–gel polycondensation at toluene in ambient air atmosphere of p-X-C6H4SiH3 (X = H, CH3, CH3O, F, Cl) to silica p-X-C6H4SiO1.5 in high yield, catalyzed by colloidal
nickel nanoparticles in-situ generated from nickelocene(II), nickel(II) acetate, and bis(1,5-cyclooctadiene)nickel(0), is described. Similar catalytic activities were observed for the catalysts. Similarly, the dry sol–gel polyco-condensation p-X-C6H4SiH3
(X = CH3, CH3O, F, Cl):C6H4SiH3 (9:1 mole ratio) at toluene in ambient air atmosphere of was performed to yield co-silicas (p-X-C6H4SiO1.5)9(p-X-C6H4SiO1.5)1
in high yield using nickelocene. The co-gels with higher molecular weights and TGA residue yield were obtained when compared to the homogels. The highest yield, molecular weight, polydispersity index, and TGA residue yield were obtained for p-Cl-C6H4SiH3.
Some degree of unreacted Si—H bonds still remained in the gel matrix because of steric bulkiness. All the insoluble gels adopt an amorphous structure with a smooth surface. A plausible mechanism for the dry sol–gel reaction was suggested.
Decrease in Work Function of Boron Ion-Implanted ZnO Thin Films
Authors: Heo Gi-Seok , Hong Sang-Jin , Park Jong-Woon , Choi Bum-Ho , Lee Jong-Ho , Shin Dong-Chan
Published: December 2007

We have fabricated boron ion-implanted ZnO thin films by ion implantation into sputtered ZnO thin films on a glass substrate. An investigation of the effects of ion doses and activation time on the electrical and optical properties of the films has been made. The electrical sheet resistance
and resistivity of the implanted films are observed to increase with increasing rapid thermal annealing (RTA)time, while decreasing as the ion dose increases. Without any RTA process, the variation of the carrier density is insensitive to the ion dose. With the RTA process, however, the carrier
density of the implanted films increases and approaches that of the un-implanted ZnO film as the ion dose increases. On the other hand, the carrier mobility is shown to decrease with increasing ion doses when no RTA process is applied. With the RTA process, however, there is almost no change
in the mobility. We have achieved the optical transmittance as high as 87% within the visible wavelength range up to 800 nm. It is also demonstrated that the work function can be engineered by changing the ion dose during the ion implantation process. We have found that the work function decreases
as the ion dose increases.
Properties of Polypropylene Nanocomposites Containing Silver Nanoparticles
Authors: Jang Myung Wook , Kim Ju-Young , Ihn Kyo Jin
Published: December 2007

Silver/polypropylene (PP) nanocomposites containing silver nanoparticles smaller than 10 nm were prepared using a new synthetic method. AgNO3 crystals were dissolved into hydrophilic domain of polyoxyethylene maleate-based surfactant (PEOM), which gives self-assembly nano-structures.
The AgNO3 in the nano-domains of PEOM was reduced by NaBH4 to form nanoparticles. The colloidal solutions with silver nanoparticles were diluted with ethanol and were mixed with PP pellets. Silver nanocomposites were prepared by extrusion compounding process after drying
the pellets. Contents of silver nanoparticles dispersed within PP resin were changed from 100 to 1000 ppm. Formation of silver nanoparticles within PP was confirmed by UV-Vis spectroscopy and TEM. Size and distribution of dispersed silver nanoparticles were also measured by TEM. Silver/PP
nanocomposites films showed not only improved thermal stability but also increased mechanical properties compared to neat PP film. Tensile properties of PP nanocomposites were largely improved compared with neat PP resin, and elongation increased also by 175% for the nanocomposites containing
1000 ppm silver nanoparticles.
The Role of Di(2-ethylhexyl)phosphoric Acid as a Cosurfactant on the Morphology Control of Mesoporous Silica Microspheres
Authors: Kim Jong-Yun , Yoon Suk Bon , Lee Myung-Ho , Park Yong Joon , Kim Won-Ho , Jee Kwang Yong
Published: December 2007

Synthesis of mesoporous silica microspheres larger than 10 μm via surfactant template approach has rarely been reported. According to the previous studies, particle morphologies were highly variable, depending on the synthesis conditions and impeller design such as impeller
type, size, and agitation speed. A new robust surfactant-template synthesis strategy for the stable suspension of large silica microspheres was investigated by introducing an additional cosurfactant. Di(2-ethylhexyl)phosphoric acid (HDEHP) as a cosurfactant played a key role in suspension
stabilization without distorting the spherical morphology as well as in the formation of uniform pore structures. High quality of mesoporous silica microspheres was obtained and compared with the Kosuge's silica under different conditions such as stirring rate, acid concentration, the amount
of solvent in a mother liquor.
Empirical Models of the Probability Distribution of Sea Surface Wind Speeds
Authors: Monahan Adam Hugh
Published: December 2007

This study considers the probability distribution of sea surface wind speeds, which have historically been modeled using the Weibull distribution. First, non-Weibull structure in the observed sea surface wind speeds (from SeaWinds observations) is characterized using relative entropy, a natural information theoretic measure of the difference between probability distributions. Second, empirical models of the probability distribution of sea surface wind speeds, parameterized in terms of the parameters of the vector wind probability distribution, are developed. It is shown that Gaussian fluctuations in the vector wind cannot account for the observed features of the sea surface wind speed distribution, even if anisotropy in the fluctuations is accounted for. Four different non-Gaussian models of the vector wind distribution are then considered: the bi-Gaussian, the centered gamma, the Gram–Charlier, and the constrained maximum entropy. It is shown that so long as the relationship between the skewness and kurtosis of the along-mean sea surface wind component characteristic of observations is accounted for in the modeled probability distribution, then all four vector wind distributions are able to simulate the observed mean, standard deviation, and skewness of the sea surface wind speeds with an accuracy much higher than is possible if non-Gaussian structure in the vector winds is neglected. The constrained maximum entropy distribution is found to lead to the best simulation of the wind speed probability distribution. The significance of these results for the parameterization of air/sea fluxes in general circulation models is discussed.
Timely Detection of Changes in the Meridional Overturning Circulation at 26°N in the Atlantic
Authors: Baehr Johanna , Haak Helmuth , Alderson Steven , Cunningham Stuart A. , Jungclaus Johann H. , Marotzke Jochem
Published: December 2007

It is investigated how changes in the North Atlantic meridional overturning circulation (MOC) might be reliably detected within a few decades, using the observations provided by the RAPID-MOC 26°N array. Previously, detectability of MOC changes had been investigated with a univariate MOC time series exhibiting strong internal variability, which would prohibit the detection of MOC changes within a few decades. Here, a modification of K. Hasselmann’s fingerprint technique is used: (simulated) observations are projected onto a time-independent spatial pattern of natural variability to derive a time-dependent detection variable. The fixed spatial pattern of natural variability is derived by regressing the zonal density gradient along 26°N against the strength of the MOC at 26°N within the coupled ECHAM5/Max Planck Institute Ocean Model’s (MPI-OM) control climate simulation. This pattern is confirmed against the observed anomalies found between the 1957 and the 2004 hydrographic occupations of the section. Onto this fixed spatial pattern of natural variability, both the existing hydrographic observations and simulated observations mimicking the RAPID-MOC 26°N array in three realizations of the Intergovernmental Panel on Climate Change (IPCC) scenario A1B are projected. For a random observation error of 0.01 kg m−3, and only using zonal density gradients between 1700- and 3100-m depth, statistically significant detection occurs with 95% reliability after about 30 yr, in the model and climate change scenario analyzed here. Compared to using a single MOC time series as the detection variable, continuous observations of zonal density gradients reduce the detection time by 50%. For the five hydrographic occupations of the 26°N transect, none of the analyzed depth ranges shows a significant trend between 1957 and 2004, implying that there was no MOC trend over the past 50 yr.
Atmosphere and Marginal-Sea Interaction Leading to an Interannual Variation in Cold-Air Outbreak Activity over the Japan Sea
Authors: Isobe Atsuhiko , Beardsley Robert C.
Published: December 2007

The interannual variation in cold-air outbreak activity over the Japan Sea is investigated using Japan Meteorological Agency buoy 21002 and Quick Scatterometer (QuikSCAT) wind data, Japan Oceanographic Data Center sea surface temperature (SST) data, NCEP–NCAR reanalysis surface wind and sea level pressure (SLP) data, and the winter Arctic Oscillation (AO) index of Thompson and Wallace. Cold-air outbreaks occur during the “winter” November–March period, and wind data for this season for the 19-winter period 1981–2000 were analyzed. Wavelet spectra averaged between 5- and 15-day periods were used to evaluate the intensity of cold-air outbreaks quantitatively. The winter mean wavelet spectra exhibited a clear interannual variation and a significant positive correlation with the AO index, indicating that intensive cold-air outbreaks frequently occur during relatively warm winters caused by a quasi-decadal AO. Based on the SST and SLP data, the low atmospheric surface pressure disturbances tend to develop over the warm East China Sea in warm winters in the positive AO phase. As these low SLP disturbances advance toward the northern Japan islands during the positive AO phase, they intensify more, leading to stronger cold-air outbreaks over the Japan Sea and increased sea surface cooling over the northern Japan Sea.
Wind Stress Drag Coefficient over the Global Ocean*
Authors: Kara A. Birol , Wallcraft Alan J. , Metzger E. Joseph , Hurlburt Harley E. , Fairall Chris W.
Published: December 2007

Interannual and climatological variations of wind stress drag coefficient (CD) are examined over the global ocean from 1998 to 2004. Here CD is calculated using high temporal resolution (3- and 6-hourly) surface atmospheric variables from two datasets: 1) the 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40) and 2) the Navy Operational Global Atmospheric Prediction System (NOGAPS). The stability-dependent CD algorithm applied to both datasets gives almost identical values over most of the global ocean, confirming the validity of results. Overall, major findings of this paper are as follows: 1) the CD value can change significantly (e.g., >50%) on 12-hourly time scales around the Kuroshio and Gulf Stream current systems; 2) there is strong seasonal variability in CD, but there is not much interannual change in the spatial variability for a given month; 3) a global mean CD ≈ 1.25 × 10−3 is found in all months, while CD ≥ 1.5 × 10−3 is prevalent over the North Pacific and North Atlantic Oceans and in southern high-latitude regions as well, and CD ≤ 1.0 × 10−3 is typical in the eastern equatorial Pacific cold tongue; and 4) including the effects of air–sea stability on CD generally causes an increase of >20% in comparison to the one calculated based on neutral conditions in the tropical regions. Finally, spatially and temporally varying CD fields are therefore needed for a variety of climate and air–sea interaction studies.
Feedback of Tropical Instability-Wave-Induced Atmospheric Variability onto the Ocean
Authors: Seo Hyodae , Jochum Markus , Murtugudde Raghu , Miller Arthur J. , Roads John O.
Published: December 2007

The effects of atmospheric feedbacks on tropical instability waves (TIWs) in the equatorial Atlantic Ocean are examined using a regional high-resolution coupled climate model. The analysis from a 6-yr hindcast from 1999 to 2004 reveals a negative correlation between TIW-induced wind perturbations and TIW-induced ocean currents, which implies damping of the TIWs. On the other hand, the feedback effect from the modification of Ekman pumping velocity by TIWs is small compared to the contribution to TIW growth by baroclinic instability. Overall, the atmosphere reduces the growth of TIWs by adjusting its wind response to the evolving TIWs. The analysis also shows that including ocean current (mean + TIWs) in the wind stress parameterization reduces the surface stress estimate by 15%–20% over the region of the South Equatorial Current. Moreover, TIW-induced perturbation ocean currents can significantly alter surface stress estimations from scatterometers, especially at TIW frequencies. Finally, the rectification effect from the atmospheric response to TIWs on latent heat flux is small compared to the mean latent heat flux.
More Than “Just a Joke”: The Prejudice-Releasing Function of Sexist Humor
Authors: Ford Thomas E. , Boxer Christie F. , Armstrong Jacob , Edel Jessica R.
Published: December 2007

The results of two experiments supported the hypothesis that, for sexist men, exposure to sexist humor can promote the behavioral release of prejudice against women. Experiment 1 demonstrated that hostile sexism predicted the amount of money participants were willing to donate to a women's organization after reading sexist jokes but not after reading nonhumorous sexist statements or neutral jokes. Experiment 2 showed that hostile sexism predicted the amount of money participants cut from the budget of a women's organization relative to four other student organizations upon exposure to sexist comedy skits but not neutral comedy skits. A perceived local norm of approval of funding cuts for the women's organization mediated the relationship between hostile sexism and discrimination against the women's organization.
Engaging with Discourse on Caste, Class and Politics in India
Authors: Pankaj Ashok K.
Published: December 2007

This article maps the changing profile of pre-Mandal and post-Mandal debates on caste, class and politics in India, showing that the centrality of caste as an agent of politics and its dominant role in public-political life has remained a reality throughout. What is contested now is the extent to which recognition of caste as an instrument of socio-political change (following the Mandal Commission) and caste-centric socio-political movements of the 1980s and 1990s (the Dalit and Backward Class movements) has reinforced caste-centric public-political life by giving it a modern value and a secular purpose.

The article argues that the contemporary elaborate discourses on caste, class, and politics in India should seek to develop new paradigms for the discussion of caste and should interrogate more vigorously the democratic and secular roles of caste in relation to class and politics.
Household hazardous waste: composition of paint waste
Authors: Fjelsted Lotte , Christensen Thomas H.
Published: December 2007

`Paint waste', a part of the `household hazardous waste', amounting to approximately 5 tonnes was collected from recycling stations in two Danish cities. Sorting and analyses of the waste showed paint waste comprised approximately 65% of the mass, paint-like waste (cleaners, fillers, etc.) comprised 15—25% and foreign items comprised 10—20%.Water-based paint was the dominant part of the paint waste. The chemical composition of the paint waste and the paint-like waste was characterized by an analysis of 27 substances in seven waste fractions. The content of critical substances was low and the paint waste was less contaminated with heavy metals than was the ordinary household waste. This may suggest that households no longer need to source-segregate their paint if the household waste is incinerated, since the presence of a small quantity of solvent-based paint will not be harmful when incinerated. Allowing household paint waste to be collected with ordinary household waste is expected to reduce the cost of handling household hazardous waste, since paint waste in Denmark comprises the major fraction of household hazardous waste.
Non-Photic Modulation of Phase Shifts to Long Light Pulses
Authors: Antle Michael C. , Sterniczuk Roxanne , Smith Victoria M. , Hagel Kimberly
Published: December 2007

Circadian rhythms can be reset by both photic and non-photic stimuli. Recent studies have used long light exposure to produce photic phase shifts or to enhance non-photic phase shifts. The presence or absence of light can also influence the expression of locomotor rhythms through masking; light during the night attenuates locomotor activity, while darkness during the day induces locomotor activity in nocturnal animals. Given this dual role of light, the current study was designed to examine the relative contributions of photic and non-photic components present in a long light pulse paradigm. Mice entrained to a light/dark cycle were exposed to light pulses of various durations (0, 3, 6, 9, or 12 h) starting at the time of lights-off. After the light exposure, animals were placed in DD and were either left undisturbed in their home cages or had their wheels locked for the remainder of the subjective night and subsequent subjective day. Light treatments of 6, 9, and 12 h produced large phase delays. These treatments were associated with decreased activity during the nocturnal light and increased activity during the initial hours of darkness following light exposure. When the wheels were locked to prevent high-amplitude activity, the resulting phase delays to the light were significantly attenuated, suggesting that the activity following the light exposure may have contributed to the overall phase shift. In a second experiment, telemetry probes were used to assess what effect permanently locking the wheels had on the phase shift to the long light pulses. These animals had phase shifts fully as large as animals without any form of wheel lock, suggesting that while non-photic events can modulate photic phase shifts, they do not play a role in the full phase-shift response observed in animals exposed to long light pulses. This paradigm will facilitate investigations into non-photic responses of the mouse circadian system.