bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of Host Cytokine Responses in the Pathogenesis of Avian H5N1 Influenza Viruses in Mice
Authors: Szretter Kristy J. , Gangappa Shivaprakash , Lu Xuihua , Smith Chalanda , Shieh Wun-Ju , Zaki Sherif R. , Sambhara Suryaprakash , Tumpey Terrence M. , Katz Jacqueline M.
Published: December 2006

Highly pathogenic avian H5N1 influenza viruses are now widespread in poultry in Asia and have recently spread to some African and European countries. Interspecies transmission of these viruses to humans poses a major threat to public health. To better understand the basis of pathogenesis of H5N1 viruses, we have investigated the role of proinflammatory cytokines in transgenic mice deficient in interleukin-6 (IL-6), macrophage inflammatory protein 1 alpha (MIP-1α), IL-1 receptor (IL-1R), or tumor necrosis factor receptor 1 (TNFR1) by the use of two avian influenza A viruses isolated from humans, A/Hong Kong/483/97 (HK/483) and A/Hong Kong/486/97 (HK/486), which exhibit high and low lethality in mice, respectively. The course of disease and the extent of virus replication and spread in IL-6- and MIP-1α-deficient mice were not different from those observed in wild-type mice during acute infection with 1,000 50% mouse infective doses of either H5N1 virus. However, with HK/486 virus, IL-1R-deficient mice exhibited heightened morbidity and mortality due to infection, whereas no such differences were observed with the more virulent HK/483 virus. Furthermore, TNFR1-deficient mice exhibited significantly reduced morbidity following challenge with either H5N1 virus but no difference in viral replication and spread or ultimate disease outcome compared with wild-type mice. These results suggest that TNF-α may contribute to morbidity during H5N1 influenza virus infection, while IL-1 may be important for effective virus clearance in nonlethal H5N1 disease.
Uterine tumour resembling ovarian sex cord tumour is an immunohistochemically polyphenotypic neoplasm which exhibits coexpression of epithelial, myoid and sex cord markers
Authors: Hurrell D P , McCluggage W G
Published: December 2006

Aims:

To describe the clinicopathological and immunohistochemical findings in four cases of uterine tumour resembling ovarian sex cord tumour (UTROSCT).

Methods:

Four UTROSCTs were stained with a wide range of antibodies, including epithelial (AE1/3, epithelial membrane antigen), myoid (desmin, α smooth muscle actin, h-caldesmon), sex cord (α inhibin, calretinin, melan A, CD99) and neuroendocrine (chromogranin, CD56) markers as well as hormone receptors (oestrogen receptor, progesterone receptor, androgen receptor), vimentin, CD10, WT1 and HMB45.

Results:

The tumours ranged from 0.8 to 19.5 cm. Three were relatively well circumscribed intramural myometrial lesions; the other was a pedunculated mass attached to the uterine serosa. The tumours were variably composed of solid, corded, trabecular, nested, glandular and retiform arrangements of tumour cells. In three cases, cells with eccentric nuclei and abundant eosinophilic cytoplasm, resulting in a rhabdoid appearance, were a prominent feature. Three cases were diffusely positive with AE1/3 and all with epithelial membrane antigen. Positivity with myoid markers was common with 3, 4 and 1 case respectively staining with desmin, α smooth muscle actin and h-caldesmon; 2, 4, 1 and 2 cases respectively were positive with α inhibin, calretinin, melan A and CD99. All were chromogranin negative and exhibited diffuse strong staining with CD56. All were diffusely positive with oestrogen receptor, progesterone receptor, vimentin and WT1. Three cases were androgen receptor positive and all were CD10 and HMB45 negative.

Conclusions:

UTROSCT exhibits a polyphenotypic immunophenotype with coexpression of markers of epithelial, myoid and sex cord lineage as well as hormone receptors.
Percutaneous absorption of aromatic amines in rubber industry workers: impact of impaired skin and skin barrier creams
Authors: Korinth G , Weiss T , Penkert S , Schaller K H , Angerer J , Drexler H
Published: December 2006

Background:Several aromatic amines (AA) could cause bladder cancer and are an occupational hygiene problem in the workplace. However, little is known about the percutaneous absorption of chemicals via impaired skin and about the efficacy of skin protection measures to reduce internal exposure.

Aims:To determine the impact of skin status and of skin protection measures on the internal exposure to AA in workers manufacturing rubber products.

Methods:51 workers occupationally exposed to aniline and o-toluidine were examined. The workplace conditions, risk factors for skin and the use of personal protective equipment were assessed by means of a self-administered questionnaire. The skin of hands and forearms was clinically examined. Exposure to aniline and o-toluidine was assessed by ambient air and biological monitoring (analyses of urine samples and of haemoglobin adducts).

Results:Haemoglobin-AA-adduct levels in workers with erythema (73%) were significantly higher (p<0.04) than in workers with healthy skin (mean values: aniline 1150.4 ng/l vs 951.7 ng/l, o-toluidine 417.9 ng/l vs 118.3 ng/l). The multiple linear regression analysis showed that wearing gloves significantly reduced the internal exposure. A frequent use of skin barrier creams leads to a higher internal exposure of AA (p<0.03). However, the use of skincare creams at the workplace was associated with a reduced internal exposure (p<0.03). From these findings we assume that internal exposure of the workers resulted primarily from the percutaneous uptake.

Conclusions:The study demonstrates a significantly higher internal exposure to AA in workers with impaired skin compared with workers with healthy skin. Daily wearing of gloves efficiently reduced internal exposure. However, an increased use of skin barrier creams enhances the percutaneous uptake of AA. Skincare creams seem to support skin regeneration and lead to reduced percutaneous uptake.
Pain tolerance in patients presenting to primary care and physiotherapy services with upper limb disorders: Table 1
Authors: Ryall Claire , Coggon David , Peveler Robert , Reading Isabel , Palmer Keith T
Published: December 2006

Background:Arm pain is a common cause of incapacity for work and is often attributed to occupational activities, but in many cases the pathogenesis is unclear.

Objective:To investigate whether arm pain in the absence of identifiable underlying pathology is associated with reduced tolerance of painful sensory stimuli.

Methods:133 incident cases of arm pain, recruited from primary care and physiotherapy services, were classified according to a validated diagnostic algorithm. Pain tolerance was measured at three sites in each arm in response to electrocutaneous stimulation. Associations with pain tolerance (the geometric mean of the six measurements at 5 Hz) were assessed by linear regression, and findings were summarised as proportional changes in pain tolerance.

Results:Pain tolerance was generally lower than in an earlier community survey. Women had a lower tolerance than men. After allowance for sex, age, use of analgesics and anatomical extent of pain, there was no indication of reduced tolerance in patients with non-specific pain relative to those with specific local pathology.

Conclusions:Pain tolerance may be generally reduced in patients presenting to medical services with arm pain, but those with non-specific pain do not seem to have lower tolerance than those with identifiable local pathology.
Pesticides and other agricultural factors associated with self-reported farmer’s lung among farm residents in the Agricultural Health Study
Authors: Hoppin Jane A , Umbach David M , Kullman Greg J , Henneberger Paul K , London Stephanie J , Alavanja Michael C R , Sandler Dale P
Published: December 2006

Background:Farmer’s lung, or hypersensitivity pneumonitis, is an important contributor to respiratory morbidity among farmers.

Methods:Using the 1993–7 enrolment data from the Agricultural Health Study, we conducted a cross-sectional study of occupational risk factors for farmer’s lung among ∼50 000 farmers and farm spouses in Iowa and North Carolina using hierarchical logistic regression controlling for age, state, and smoking status. Participants provided information on agricultural exposures, demographic characteristics, and medical history via self-administered questionnaires. Approximately 2% of farmers (n = 481) and 0.2% of spouses (n = 51) reported doctor-diagnosed farmer’s lung during their lifetime. We assessed farmers and spouses separately due to different information on occupational exposure history. Only pesticide exposures represented lifetime exposure history, all other farm exposures represented current activities at enrolment.

Results:Among farmers, handling silage (OR = 1.41, 95% CI 1.10 to 1.82), high pesticide exposure events (OR = 1.75, 95% CI 1.39 to 2.21), and ever use of organochlorine (OR = 1.34, 95% CI 1.04 to 1.74) and carbamate pesticides (OR = 1.32, 95% CI 1.03 to 1.68) were associated with farmer’s lung in mutually-adjusted models. The insecticides DDT, lindane, and aldicarb were positively associated with farmer’s lung among farmers. Current animal exposures, while not statistically significant, were positively associated with farmer’s lung, particularly for poultry houses (OR = 1.55, 95% CI 0.93 to 2.58) and dairy cattle (OR = 1.28, 95% CI 0.86 to 1.89). The occupational data were more limited for spouses; however, we saw similar associations for dairy cattle (OR = 1.50, 95% CI 0.72 to 3.14) and organochlorine pesticides (OR = 1.29, 95% CI 0.64 to 2.59).

Conclusion:While historic farm exposures may contribute to the observed associations with pesticides, these results suggest that organochlorine and carbamate pesticides should be further evaluated as potential risk factors for farmer’s lung.
Association of allergic rhinitis with pesticide use among grape farmers in Crete, Greece
Authors: Chatzi Leda , Alegakis Athanasios , Tzanakis Nikolaos , Siafakas Nikolaos , Kogevinas Manolis , Lionis Christos
Published: December 2006

Objective:To explore the association of allergic rhinitis with the use of pesticides among grape farmers in Crete.

Methods:A cross-sectional study of 120 grape farmers and 100 controls at the Malevisi region in Northern Crete was conducted. The protocol consisted of a questionnaire, skin prick tests for 16 common allergens, measurement of specific IgE antibodies against 8 allergens, and spirometry before and after bronchodilatation.

Results:Grape farmers who used pesticides had higher prevalence rates of allergic rhinitis symptoms (OR, 3.0; 95% CI, 1.4 to 6.2) compared with grape farmers who reported no current use of pesticides, and control subjects. Logistic regression models controlling for age, sex and smoking status showed that 6 of the 12 predefined groups of major pesticides were significantly related to allergic rhinitis symptoms. The highest risks were observed for paraquat and other bipyridyl herbicides (OR, 2.2; 95% CI, 1.0 to 4.8), dithiocarbamate fungicides (OR, 2.5; 95% CI, 1.1 to 5.3) and carbamate insecticides (OR, 3.0; 95% CI, 1.4 to 6.5). A factor analysis of pesticides used identified 3 distinct factors. The most common factor was that of multiple pesticide use that included 9 pesticides and was significantly associated with allergic rhinitis (OR, 1.5; 95% CI, 1.0 to 2.3). ORs were higher when allergic rhinitis was defined using both questionnaire data on symptoms and atopy.

Conclusions:Occupational exposure to multiple agricultural chemicals could be related to allergic rhinitis in grape farmers.
STANDARD-FREE METHOD FOR BEARD SAMPLES OF VERY SMALL QUANTITY
Authors: SERA K. , ITOH J. , SAITOH Y. , FUTATSUGAWA S.
Published: December 2006

We developed and reported standard-free methods for various samples such as hair, nail, urine, serum, sweat, snivel, tear and saliva, and they have been confirmed to be effective for addressing global environmental issues. It is expected that analyses of beard samples give us useful information about daily changes of elemental concentration in the body in comparison with the other samples. In this work, a quantitative method for untreated beard analysis based on the standard-free method has been developed. By means of the method, it becomes possible to quantitatively analyze extremely small quantity of beard samples, which are daily taken with ordinary electric shaver. The optimum conditions of washing samples have also been examined. It is found that some elements such as potassium, calcium and chlorine are lost by washing in distilled water and it is better to wash the sample in acetone. As a result, the standard-free method for beard samples has been successfully established and good accuracy and reproducibility were achieved.
STUDIES ON DAILY CHANGES OF ELEMENTAL CONCENTRATION IN BEARD SAMPLES BY MEANS OF THE STANDARD-FREE METHOD
Authors: SERA K. , SASAKI T. , ITOH J. , SAITOH Y.
Published: December 2006

We developed and reported a standard-free method for beard (including mustache and whiskers) samples that enables us to quantitatively analyze powdered beard samples of extremely small quantity. In order to investigate intake of essential elements and also exposure to toxic elements, daily changes of elemental concentration in the body give us essential information. Firstly, we have measured dependence of elemental concentration in beard, mustache and whiskers on the collecting regions in the face. Then, daily changes of elemental concentration in the body, which reflect daily ingestion of foods and waters, have been estimated by means of quantitative analyses of beard samples. These beard samples were taken from three persons everyday over successive 7, 14 and 33 days, respectively. As a result, some elements show long-term changes and a few toxic elements such as arsenic and lead exhibit changes in a period of a few days. We have also measured daily changes of elemental concentration in urine and beard taken from the same person at the same time every half day over 10 days, and clear correlation of daily changes of the arsenic concentration between urine and beard samples was observed. It is found that the standard-free method is quite effective for beard samples of very small quantities, and that beard analyses are quite suited to studies on daily changes of elemental concentration in the human body in comparison with the other samples depending on the elements.
ELEMENTAL ANALYSIS OF VEGETABLES ON THE MARKET — Comparison with Wild Plants
Authors: ITOH J. , SAITOH Y. , FUTATSUGAWA S. , SERA K.
Published: December 2006

We have measured concentration of multi elements in vegetables on the market and a wild plant gathered around Nishina Memorial Cyclotron Center in Iwate prefecture by means of PIXE. Elemental concentration in vegetables cultivated by spraying mineral-rich waters was also analyzed. As a result, it is found that the mineral-supplying vegetables abundantly contain essential elements for body such as K , Ca , Fe , Cu and Zn in comparison with ordinary ones. With regard to a wild plant, concentration of essential elements such as Ca , Cu and Zn shows no clear difference in comparison with that in commercially available one of the same kind, while that of toxic elements such as Cr and Pb is relatively higher. Moreover, it is suggested that the wild plant has a certain property of concentrating a specific element depending on its growing period. The relation between elemental concentration in the plants and that in their growing environment, such as water and soil, was also examined. It is also suggested that elemental concentration in vegetables reflects elemental constituent not only of the soil but also of the sprayed water as well as of the fertilizer.
ELEMENTAL ANALYSIS OF URANOUCHI BAY SEABED SLUDGE USING PIXE
Authors: KABIR M. HASNAT , NARUSAWA TADASHI , NISHIYAMA FUMITAKA , SUMI KATSUHIRO
Published: December 2006

Elemental analyses were carried out for the seabed sludge collected from Uranouchi bay (Kochi, Japan) using Particle Induced X-ray Emission (PIXE). Seabed-sludge contamination with heavy metals as well as toxic elements becomes one of the most serious environmental problems. The aim of the present study is to investigate the polluted areas in the bay by heavy and toxic elements. As a results of analyses of samples collected from eleven different places in the bay, seventeen elements including toxic ones were detected. The results suggest that the center region of the bay is seriously contaminated by heavy and toxic elements in comparison with the other areas in the bay.
NITROGEN LATTICE LOCATION IN MOVPE GROWN Ga1-xInxNyAs1-y FILMS USING ION BEAM CHANNELING
Authors: NEBIKI TAKUYA , NARUSAWA TADASHI , KUMAGAI AKIKO , DOI HIDEYUKI , SAITO TADASHI , TAKAGISHI SHIGENORI
Published: December 2006

We have investigated the nitrogen lattice location in MOVPE grown Ga 1- x In x N y As 1- y with x = 0.07 and y = 0.025 by means of ion beam channeling technique. In this system, the lattice constant of the Ga 1- x In x N y As 1- y film is equal to GaAs lattice. Therefore, we can grow apparently no strain, high quality and very thick GaInNAs film on GaAs substrate. The quality of the films as well as the lattice location of In and N were characterized by channeling Rutherford backscattering spectrometry and nuclear reaction analysis using 3.95 MeV He 2+ beam. The fraction of substitutional nitrogen in the film was measured using the 14 N (α, p )17 O endothermic nuclear reaction. Our results indicate that more than 90% of In and N atoms are located the substitutional site, however, N atoms are slightly displaced by ~0.2 Å from the lattice site. We suggest that the GaInNAs film has a local strain or point defects around the N atoms.
Minimizing Waiting Ratio for Dynamic Workload on Parallel Computers
Authors: Huang Kuo-Chan
Published: December 2006

This paper proposes waiting ratio as a basis in evaluating various scheduling methods for dynamic workloads consisting of multi-processor jobs on parallel computers. We evaluate commonly used methods as well as several methods proposed in this paper by simulation studies. The results indicate that some commonly used methods do not improve the waiting ratios as expected by intuition, while some methods proposed in this paper do greatly improve waiting ratios more than 10 times for some workload data, promising in leading to more reasonable waiting time and better user's satisfaction.
OPTIMAL CLUSTERING SIZE OF SMALL FILE ACCESS IN NETWORK ATTACHED STORAGE DEVICE
Authors: DENG YUHUI , WANG FRANK , HELIAN NA , FENG DAN , ZHOU KE
Published: December 2006

Email and short message service are pervasive on the Internet now and continue to grow rapidly, which propels the research on small file access in storage systems. The Clustering technology places logical data blocks of multiple small files on physically contiguous disk blocks and accesses them as a single unit, which is normally adopted to improve small file access performance. This paper constructs a mathematical analysis model to discover the optimal clustering size of small file access in Network Attached Storage (NAS). The analysis results indicate that the optimal clustering size for small file access is the product of one cylinder size and disk number in NAS. Experimental results give a useful validation of our analysis. The analysis results can be applied to optimize the NAS oriented system software and the corresponding application software design.
OPTIMAL SELECTION OF COLLIERIES FOR RECONSTRUCTION: AN APPLICATION OF FUZZY 0-1 LINEAR PROGRAMMING
Authors: CHAKRABORTY M. , RAY ANANYA
Published: December 2006

Zero-one linear programming is a well-accepted approach for decision making for many real world problems. Optimal selection of collieries from a set of collieries for reconstruction is a policy of the concerned authority. The selected collieries are funded for reconstruction based on certain criteria. No colliery will be partially funded, as it is not possible to reconstruct the colliery partially so it is required either to select or reject a colliery for reconstruction. Further, in the real field generally the data available are imprecise in nature. The present paper is concerned with the application of fuzzy 0-1 linear programming to select optimally a set of collieries from a given set of colliery projects for reconstruction with an optimal planning under existing constraints and fuzzy goals. The reconstruction problem is posed as multi objective decision making problem. The application potentiality of the model has been examined by using it in the context of a group of collieries need reconstruction investments in the Jharia Coalfield, Jharkhand, INDIA.
ROLE-BASED SERIALIZABILITY USING ROLE ORDERING SCHEDULERS
Authors: ENOKIDO TOMOYA
Published: December 2006

In the role-based access control model, a role is a set of access rights. A subject doing jobs is granted roles showing the jobs in an enterprise. A transaction issued by a subject is associated with a subset of roles granted to the subject, which is named purpose. A method with a more significant purpose is performed before another method with a less significant purpose. We discuss which purpose is more significant than another purpose. We discuss two types of Role-Ordering (RO) schedulers SRO and PRO where multiple conflicting transactions are serializable in the significant order of subjects and purposes, respectively. We evaluate the RO schedulers compared with the traditional two-phase locking protocol in terms of throughput.
SUPPORTING RUNTIME RECONFIGURATION ON NETWORK PROCESSORS
Authors: LEE KEVIN , COULSON GEOFFREY
Published: December 2006

Network Processors (NPs) are set to play a key role in the next generation of networking technology. They have the performance of ASIC-based routers whilst offering a high degree of programmability. However, the programmability potential of NPs can only be realised with appropriate software. In this paper we argue that specialised software to support runtime reconfiguration is needed to fully exploit the potential of NPs. We first justify supporting runtime reconfiguration on NPs by offering real-world scenarios and discussing the issues associated with these. We then demonstrate how runtime reconfiguration can be achieved in practice through a case study of our component-based programming approach on the Intel IXP2400 NP.
LARGE DEVIATIONS FOR SMALL PERTURBATIONS OF SDES WITH NON-MARKOVIAN COEFFICIENTS AND THEIR APPLICATIONS
Authors: GAO FUQING , LIU JICHENG
Published: December 2006

We prove large deviation principles for solutions of small perturbations of SDEs in Hölder norms and Sobolev norms, where the SDEs have non-Markovian coefficients. As an application, we obtain a large deviation principle for solutions of anticipating SDEs in terms of (r, p) capacities on the Wiener space.
STATISTICAL PROPERTIES OF ONE-DIMENSIONAL MAPS WITH CRITICAL POINTS AND SINGULARITIES
Authors: DÍAZ-ORDAZ K. , HOLLAND M. P. , LUZZATTO S.
Published: December 2006

We prove that a class of one-dimensional maps with an arbitrary number of non-degenerate critical and singular points admits an induced Markov tower with exponential return time asymptotics. In particular the map has an absolutely continuous invariant probability measure with exponential decay of correlations for Hölder observations.
FABRICATION OF DISPERSED ALIGNED CARBON NANOTUBE ARRAY BETWEEN METAL ELECTRODES
Authors: CHEN CHANGXIN , ZHANG YAFEI
Published: December 2006

Dispersed aligned single-wall carbon nanotube (SWCNT) array has been formed between electrodes by electric field assisted alignment of surface decorated SWCNTs. The surface decoration of SWCNTs with functional molecules allows them to dispersedly bridge metal electrodes and effectively obviates the entanglement between SWCNTs. The influences of solution volatility and electric-field type on the alignment are investigated. It is indicated that the well-oriented SWCNT array can be achieved by using the high-volatility solvent and the high-frequency AC electric field to align SWCNTs.
TRANSPORT PROPERTIES OF C60 MONOLAYERS GROWN ON NANOSTRUCTURED Au ULTRA-FINE FILMS
Authors: OKUYAMA H. , KINJO A. , TUO F. , IWATA N. , YAMAMOTO H.
Published: December 2006

The Au ultra-fine films were grown by MBE or magnetron sputtering on Al 2 O 3 or MgO single crystals which were annealed at 1000°C to obtain smooth surfaces with a step-terrace structure. A one-dimensional alignment of Au particles was partially observed around the steps on Al 2 O 3(0001), [Formula: see text] surfaces at about 600°C. On the other hand, Au ultra-fine films were also deposited by magnetron sputtering on MgO (100). The two processes were proceeded to obtain C 60 monolayers on the above Au films. Only C 60 molecules adsorbed on Au remained and the others were re-evaporated by annealing at 350°C. By this re-evaporation method the nanostructured C 60 monolayers were fabricated. In addition self-assembly monolayers of a C 60 derivative, C 60- O - C 8 SH , ( C 60-SAM) were synthesized on the Au/MgO by soaking in benzene solution of the C 60 derivative. The C 60-SAM was obtained only along the step edges. In the case of C 60-SAM on ultra-fine Au films/ MgO several samples showed the resistivity anomalies at 150–250 K accompanying with specific deviation from metallic linear dependences on temperature.
FORMATION OF CARBON NANOSTRUCTURES DURING PYROLYSIS OF POLYMERS
Authors: MANOCHA L. M. , VALAND JIGNESH , MANOCHA S.
Published: December 2006

Carbon nanomaterials have been of great interest in nanoscience and nanotechnology because of their very small size with unique properties and simplicity in structure having only one chemical element. In our laboratory, attempts were made to synthesize carbon nanomaterials through different routes such a CCVD and pyrolysis of solids carbonaceous precursors. Pyrolysis of polyacrylonitrile fibers in presence of a suitable catalyst resulted in formation of straight as well as coil type long carbon nanofibers and tubes along with general-purpose carbon fibers. Similarly, growth of carbon nanotubes was also observed in the coke deposits during pyrolysis of pitches. The yield of CNTs formed was found to increase if the precursors are impregnated with a suitable catalyst solution. These carbon nanostructures have been characterized using XRD, TEM, SEM and TGA.
ELECTROSTATIC NANOPARTICLE FILTER FOR ATOMIC SCALE FABRICATION IN LOW-TEMPERATURE PLASMAS
Authors: RUTKEVYCH P. P. , OSTRIKOV K. , XU S.
Published: December 2006

The means of reducing nanoparticle contamination in the synthesis of carbon nanostructures in reactive Ar + H 2 + CH 4 plasmas are studied. It is shown that by combining the electrostatic filtering and thermophoretic manipulation of nanoparticles, one can significantly improve the quality of carbon nanopatterns. By increasing the substrate heating power, one can increase the size of deposited nanoparticles and eventually achieve nanoparticle-free nanoassemblies. This approach is generic and is applicable to other reactive plasma-aided nanofabrication processes.
A STUDY ON THE PRECIPITATION OF Ge-RICH NANOPARTICLES IN A LUMINESCENT (Er, Ge) CO-DOPED SiO2 FILM SPUTTERED WITH Ar + O2 PLASMA
Authors: HENG C. L. , LI Y. J. , MAYANDI J. , FINSTAD T. G. , JØRGENSEN S. , GUNNÆS A. E. , OLSEN A. , STORÅS P.
Published: December 2006

We report the photoluminescence (PL) from an ( Er , Ge ) co-doped SiO 2 film deposited by rf-magnetron sputtering in an Ar + O 2 ambience. The sample film was annealed in N 2 for 30 min at different temperatures. The PL intensity increases as the annealing temperature increases from 700 to 1000°C, and drops to very weak after 1100°C annealing. High-resolution transmission electron microscopy (TEM) observation shows that there are some Ge -rich nanoparticles precipitated after 700°C annealing, and more clusters precipitated after 1000°C annealing. However, no Ge nanocrystals were found in these films, the diffraction patterns are always halo which indicates that the precipitated clusters are in amorphous states. X-ray photoelectron spectroscopy (XPS) analysis indicates the Ge in the nanoclusters is mostly in an oxidized state and the oxidation state of Er increases with increasing annealing temperature.
SYNTHESIS OF MESOPOROUS HYDROXYAPATITE THROUGH NEUTRAL TEMPLATING
Authors: ZHAO Y. F. , MA J. , TAN GEOFFREY ENG BENG
Published: December 2006

Mesoporous materials were synthesized through ionic supramolecular templating for the first time by the scientists at Mobil Oil Research and Development in 1992. However more and more efforts were put into the neutral templating route in recent years due to the limitation of ionic route. In this study, mesoporous hydroxyapatite ( Ca 10( PO 4)6( OH )2 or HA) was synthesized using nonionic block copolymer pluronic F127 (EO99PO65EO99) as template. Two groups of HA samples were prepared by coprecipitation method with different concentrations of the surfactant, which were characterized by means of X-ray diffraction (XRD), small angle XRD, electron microscopes and BJH gas absorption method. It was found that the as-synthesized and calcined samples of the two groups had a typical HA crystal phase, but the particle morphologies and pore size distribution were significantly different, depending on the surfactant concentration used. When a high surfactant concentration (10 g F127/100 g distilled water) was used, the sample obtained consisted of spherical particles (~100 nm in diameter), with a maximum distribution of pore size 58 Å. However, when the F127 concentration was 3 g/100 g distilled water, the sample with rod-like particles (~100–300 nm in length and ~40–50 nm in diameter) could be obtained, and a bimodal pore size distribution at 25.3 Å and 30 Å were also observed in this sample.
STUDIES ON ELECTRODEPOSITED NANOMETRIC Co/Cu MULTILAYERS
Authors: GUPTA PRIYANKA , SHIVAGAN D. D. , PANDYA DINESH K. , KASHYAP SUBHASH C. , CHAUDHARY SUJEET
Published: December 2006

Co/Cu multilayers were electrodeposited in potentiostatic mode, using two different sulphate baths, one without any additive and other containing trisodium citrate. Deposition parameters, like deposition potential and deposition time, were established for both the baths by carrying out a series of cyclic voltammetry and chronoamperometric experiments. Thin films, having 2–20 bilayers, were electrodeposited under the established parameters. It was observed that films deposited from bath containing trisodium citrate were comparatively much smoother than films deposited from additive free bath. The films with 20 bilayers, deposited from additive free bath, exhibited a room temperature magnetoresistance of 1.5% at 9 kG, whereas magnetoresistance value enhanced to up to 5.6% at 9 kG for films deposited from trisodium citrate bath for same number of bilayers.
AN ANALYTICAL MODEL ON REMANENCE ENHANCEMENT IN NANOSIZED PERMANENT/COMPOSITE MAGNETS
Authors: ZHAO G. P. , LIANG J. , SUN M. J. , ZHOU G. , ZHAO G. Z.
Published: December 2006

Remanence enhancement has been calculated for a range of configurations, including 1D (one-dimensional), 2D and 3D arrays of hard magnetic grains, composites of hard and soft magnetic grains and triple-films. A linear relationship between the remanence Mr and the reduced domain wall width W/L has been derived analytically, which is consistent with available experimental and numerical data. For composite materials with a soft phase inserted among hard phases, the soft grain behaves like a massive inter-grain domain-wall and results in more effective remanence enhancement. In view of this, a unified formula is reached which can be applied to both composite and single phased magnets with in-plane random easy axis distribution.
A MOLECULAR DIODE BASED ON CONJUGATED CO-OLIGOMERS
Authors: BAI PING , CHONG CHEE CHING , LI ER PING , CHEN ZHIKUAN
Published: December 2006

A molecular diode based on a conjugated co-oligomer composed of p-type and n-type segments is investigated using the first principles method. The co-oligomer is connected to Au electrodes to form an Au –oligomer– Au system. The infinite system is dealt with a finite structure confined in a device region and effects from semi-infinite electrodes. Density functional theory and nonequilibrium Green's function are used to describe the device region self-consistently. The current–voltage (I–V) characteristics of the constructed system are calculated and a rectification behavior is observed. The energy gap and the spatial orientation of molecular orbitals, and the transmission functions are calculated to analyze the I–V characteristics of the molecular diode.
EFFECTS OF CARBON SOURCE ON THE TITANIUM NITRIDE POWDER SYNTHESIZED BY CARBON THERMAL REDUCTION
Authors: TAN GUOQIANG , MIAO HONGYAN , DONG MIN , REN HUIJUN
Published: December 2006

Glucose, carbamide and petroleum coke as carbon sources are separately added to butyl titanate and ethanol system. The initial powder containing titanium source and carbon source is prepared by sol–gel method. IR analysis of the initial powder shows that: glucose-butyl titanate system and carbamide-butyl titanate system form water-soluble compounds. After being dried, they form Ti 2 O 3 and C mixed powder. Petroleum coke-butyl titanate system forms TiO 2 powder with nanometer size in carbon. Regarding initial powder as a raw material, titanium nitride powder is prepared by carbon thermal reduction. The XRD analysis shows that the titanium nitride powder is formed after the initial powder prepared in petroleum coke-butyl titanate system is kept at 1350°C for 5 h. The added Fe 2 O 3 accelerates the synthesis of titanium nitride; the initial powder prepared in glucose-butyl titanate is kept at 1400°C for 5 h and then synthesizes the titanium nitride powder. Fe 2 O 3 does not accelerate the synthesis of titanium nitride. The initial powder prepared in carbamide-butyl titanate system is found to form volatile material in N 2, but no titanium nitride powder is found.
SYNTHESIS OF FULLERODENDRON AND ITS PHOTOCATALITIC ACTIVITY
Authors: TAKAGUCHI YUTAKA , TSUBOI TAKAAKI , SAKO YUUKI , TSUBOI SADAO
Published: December 2006

A newly designed fullerodendron was synthesized in good yield (84%) by the use of a Diels-Alder reaction of C 60 with an anthryl dendron. Interestingly, the fullerodendron acts as a new catalyst that uses oxygen and light to generate singlet oxygen (1 O 2). The dendron facilitates various types of singlet oxygenation reactions including ene reaction, Diels-Alder reaction, and oxidation of phenol and sulfide.
SIMULATION OF ION FLUX DISTRIBUTION IN CONDUCTIVE AND NONCONDUCTIVE NANOTIP PATTERNS
Authors: LEVCHENKO I. , OSTRIKOV K.
Published: December 2006

The distribution of flux of carbon-bearing cations over nanopatterned surfaces with conductive nanotips and nonconductive nanoislands is simulated using the Monte-Carlo technique. It is shown that the ion current is focused to nanotip surfaces when the negative substrate bias is low and only slightly perturbed at higher substrate biases. In the low-bias case, the mean horizontal ion displacement caused by the nanotip electric field exceeds 10 nm. However, at higher substrate biases, this value reduces down to 2 nm. In the nonconductive nanopattern case, the ion current distribution is highly nonuniform, with distinctive zones of depleted current density around the nanoislands. The simulation results suggest the efficient means to control ion fluxes in plasma-aided nanofabrication of ordered nanopatterns, such as nanotip microemitter structures and quantum dot or nanoparticle arrays.
A HYBRID MODEL ON HYSTERESIS LOOP AND COERCIVITY IN NANOSTRUCTURED PERMANENT MAGNETS
Authors: SUN M. J. , ZHAO G. P. , LIANG J. , ZHOU G. , LIM H. S. , FENG Y. P.
Published: December 2006

A simplified micromagnetic model has been proposed to calculate the hysteresis loops of nanostructured permanent magnets for various configurations, including thin films, exchange-coupled double-layer systems and bulk materials. The reversal part of the hysteresis is based on the Stoner–Wohlfarth coherent rotational model and the coercivity mechanism is due mainly to the motion of the transition region (a domain wall like magnetic moment distribution in the grain boundary). The elements of nucleation and pinning models are also incorporated.
MOLECULAR DYNAMICS SIMULATION OF NANOMETRIC CUTTING PROCESS
Authors: PEI Q. X. , LU C. , FANG F. Z. , WU H.
Published: December 2006

Nanoscale machining involves changes in only a few atomic layers at the surface. Molecular dynamics (MD) simulation can play a significant role in addressing a number of machining problems at the atomic scale. In this paper, we employed MD simulations to study the nanometric cutting process of single crystal copper. Instead of the widely used Morse potential, we used the Embedded Atom Method (EAM) potential for this study. The simulations were carried out for various tool geometries at different cutting speeds. Attention was paid to the cutting chip formation, the cutting surface morphology and the cutting force. The MD simulation results show that both the tool geometry and the cutting speed have great influence on the chip formation, the smoothness of machined surface and the cutting force.
FABRICATION OF ZIRCONIUM OXIDE NANOCRYSTALLITES AND THE CRITICAL SIZE OF THE PHASE TRANSITION
Authors: TSUNEKAWA SHIN , KAWAZOE YOSHIYUKI , KOJIMA TAKASHI , SUGIMOTO TADAO
Published: December 2006

Pure zirconium oxide nanocrystalline particles of the size range 6–140 nm in diameter are fabricated from ultrafine metallo-organic complexes by thermal hydrolysis at 120°C and heat treatment at 125 to 1025°C. X-ray powder diffraction for nearly monodispersed nanocrystallites reveals that the critical size of the ferroelastic transition between the tetragonal and monoclinic phases is around 25 nm in diameter. The critical size from the cubic to the tetragonal is strongly suggested to be 5 nm in diameter by X-ray photoelectron spectroscopy.
Transition Beneath Vortical Disturbances
Authors: Durbin Paul , Wu Xiaohua
Published: December 2006

Theory and computer simulations have led to advances in the fundamental understanding of how vortical disturbances induce transition in an underlying boundary layer. It is an intriguing process whereby the shear filters the disturbance, admitting only long streamwise wavelengths into the boundary layer. These develop into strong jets in the perturbation velocity field, which lift up into the upper portion of the layer. Then shorter wavelength perturbations trigger breakdown, ultimately producing a turbulent patch near the wall. Pertinent linear theory has evolved with time, but only with recent computer simulations has it been fitted into a picture of transition beneath vortical disturbances.
The Fluid Mechanics Inside a Volcano
Authors: Gonnermann Helge M. , Manga Michael
Published: December 2006

The style and evolution of volcanic eruptions are dictated by the fluid mechanics governing magma ascent. Decompression during ascent causes dissolved volatile species, such as water and carbon dioxide, to exsolve from the melt to form bubbles, thus providing a driving force for the eruption. Ascent is influenced not only by the nucleation and growth of gas bubbles, but also magma rheology and brittle deformation (fragmentation). In fact, all processes and magma properties within the conduit interact and are coupled. Ultimately, it is the ability of gas trapped within growing bubbles to expand or to be lost by permeable gas flow, which determines whether ascending magmas can erupt nonexplosively. We review and integrate models of the primary conduit processes to show when each process or property dominates and how these interact within a conduit. In particular, we illustrate how and why ascent rate may control eruptive behavior: slowly ascending magmas erupt effusively and rapidly ascending magmas erupt explosively.
Thermofluid Modeling of Fuel Cells
Authors: Young John B.
Published: December 2006

Fuel cells offer the prospect of silent electrical power generation at high efficiency with near-zero pollutant emission. Many materials and fabrication problems have now been solved and attention has shifted toward system modeling, including the fluid flows that supply the cells with hydrogen and oxygen. This review describes the current thermofluid modeling capabilities for proton exchange membrane fuel cells (PEMFCs) and solid oxide fuel cells (SOFCs), the most promising candidates for commercial exploitation. Topics covered include basic operating principles and stack design, convective-diffusive flow in porous solids, special modeling issues for PEMFCs and SOFCs, and the use of computational fluid dynamics (CFD) methods.
Regulatory interactions of N1303K-CFTR and ENaC inXenopusoocytes: evidence that chloride transport is not necessary for inhibition of ENaC
Authors: Suaud Laurence , Yan Wusheng , Carattino Marcelo D. , Robay Amal , Kleyman Thomas R. , Rubenstein Ronald C.
Published: December 2006

Regulatory interactions of the cystic fibrosis transmembrane conductance regulator (CFTR) and the epithelial Na+channel (ENaC) are readily apparent in Xenopus oocytes. However, the mechanism underlying these interactions remains controversial. CFTR's first nucleotide binding fold (NBD-1) may be important in these interactions, as dysfunctional CFTRs containing mutations within NBD-1, such as ΔF508 and G551D, lack such functional interactions with murine ENaC (mENaC). We hypothesized that a dysfunctional CFTR containing a non-NBD-1 mutation would retain regulatory interactions with mENaC and tested this hypothesis for N1303K-CFTR, where the mutation is located in CFTR's second nucleotide binding fold (NBD-2). cRNA for αβγ-mENaC and N1303K-CFTR was injected separately or together into Xenopus oocytes. ENaC and CFTR functional expression was assessed by two-electrode voltage clamp. Injection of N1303K (class II trafficking mutation) yielded low levels of CFTR function on activation with forskolin and 3-isobutyl-1-methylxanthine (IBMX). In coinjected oocytes, N1303K did not alter mENaC functional expression or surface expression before activation of N1303K. This is similar to our prior observations with ΔF508. However, unlike our observations with ΔF508, activation of N1303K acutely decreased mENaC functional and surface expression, and N1303K currents were enhanced by coinjection of mENaC. Furthermore, genistein only mildly enhanced the functional expression of N1303K-CFTR and did not improve regulation of ENaC by N1303K-CFTR. These data suggest that a structurally and functionally intact CFTR NBD-1 in activated CFTR can regulate mENaC surface expression independent of Cl−transport in Xenopus oocytes.
Elevated resting [Ca2+]i in myotubes expressing malignant hyperthermia RyR1 cDNAs is partially restored by modulation of passive calcium leak from the SR
Authors: Yang Tianzhong , Esteve Eric , Pessah Isaac N. , Molinski Tadeusz F. , Allen Paul D. , López José R.
Published: December 2006

Malignant hyperthermia (MH) is a pharmacogenetic disorder of skeletal muscle triggered in susceptible individuals by inhalation anesthetics and depolarizing skeletal muscle relaxants. This syndrome has been linked to a missense mutation in the type 1 ryanodine receptor (RyR1) in more than 50% of cases studied to date. Using double-barreled Ca2+ microelectrodes in myotubes expressing wild-type RyR1 ( WTRyR1) or RyR1 with one of four common MH mutations ( MHRyR1), we measured resting intracellular Ca2+ concentration ([Ca2+]i). Changes in resting [Ca2+]i produced by several drugs known to modulate the RyR1 channel complex were investigated. We found that myotubes expressing any of the MHRyR1s had a 2.0- to 3.7-fold higher resting [Ca2+]i than those expressing WTRyR1. Exposure of myotubes expressing MHRyR1s to ryanodine (500 μM) or (2,6-dichloro-4-aminophenyl)isopropylamine (FLA 365; 20 μM) had no effects on their resting [Ca2+]i. However, when myotubes were exposed to bastadin 5 alone or to a combination of ryanodine and bastadin 5, the resting [Ca2+]i was significantly reduced ( P < 0.01). Interestingly, the percent decrease in resting [Ca2+]i in myotubes expressing MHRyR1s was significantly greater than that for WTRyR1. From these data, we propose that the high resting myoplasmic [Ca2+]i in MHRyR1 expressing myotubes is due in part to a related structural conformation of MHRyR1s that favors “passive” calcium leak from the sarcoplasmic reticulum.
Altered pHi regulation and Na+/HCO3− transporter activity in choroid plexus of cilia-defective Tg737orpk mutant mouse
Authors: Banizs Boglarka , Komlosi Peter , Bevensee Mark O. , Schwiebert Erik M. , Bell Phillip D. , Yoder Bradley K.
Published: December 2006

Tg737 orpk mice have defects in cilia assembly and develop hydrocephalus in the perinatal period of life. Hydrocephalus is progressive and is thought to be initiated by abnormal ion and water transport across the choroid plexus epithelium. The pathology is further aggravated by the slow and disorganized beating of motile cilia on ependymal cells that contribute to decreased cerebrospinal fluid movement through the ventricles. Previously, we demonstrated that the hydrocephalus phenotype is associated with a marked increase in intracellular cAMP levels in choroid plexus epithelium, which is known to have regulatory effects on ion and fluid movement in many secretory epithelia. To evaluate whether the hydrocephalus in Tg737 orpk mutants is associated with defects in ion transport, we compared the steady-state pHi and Na+-dependent transport activities of isolated choroid plexus epithelium tissue from Tg737 orpk mutant and wild-type mice. The data indicate that Tg737 orpk mutant choroid plexus epithelium have lower pHi and higher Na+-dependent HCO3− transport activity compared with wild-type choroid plexus epithelium. In addition, wild-type choroid plexus epithelium could be converted to a mutant phenotype with regard to the activity of Na+-dependent HCO3− transport by addition of dibutyryl-cAMP and mutant choroid plexus epithelium toward the wild-type phenotype by inhibiting PKA activity with H-89. Together, these data suggest that cilia have an important role in regulating normal physiology of choroid plexus epithelium and that ciliary dysfunction in Tg737 orpk mutants disrupts a signaling pathway leading to elevated intracellular cAMP levels and aberrant regulation of pHi and ion transport activity.
Nitric oxide pathway counteracts enhanced contraction to membrane depolarization in aortic rings of rats on high-sodium diet
Authors: Cordaillat Magali , Fort Aurélie , Virsolvy Anne , Elghozi Jean-Luc , Richard Sylvain , Jover Bernard
Published: December 2006

Vascular smooth muscle cell contraction and endothelium-dependent relaxation was evaluated in aortic rings isolated from weaned, 5-mo-old Sprague-Dawley rats fed a normal (NS; 0.8% NaCl) or high (HS; 8% NaCl) sodium diet. Arterial pressure was 140 ± 6 (NS) and 145 ± 6 mmHg (HS). In endothelium-denuded rings, the response to phenylephrine (PE) was not modified by the sodium diet, while that of depolarizing agent KCl and intracellular calcium releasing agent caffeine increased in the HS group. When endothelium was preserved, PE-evoked contraction was reduced in both NS and HS groups, the contraction being yet lower in the HS group. This effect was partially obliterated by addition of NG-nitro-l-arginine methyl ester (l-NAME), independently of the sodium diet. Relaxation to ACh in intact rings and to sodium nitroprusside (SNP) and 8-bromoadenosine 3′5′ cyclic guanosine monophosphate (8-BrcGMP) in the absence of endothelium was enhanced in rings isolated from HS rats. In addition, the dose-response curve to 8-BrcGMP was shifted to the right in the presence of iberiotoxin, an inhibitor of large conductance, voltage-dependent, and calcium-sensitive potassium channel (BKCa). However, shift was more marked in rings from HS rats. Present results provide evidence that response of vascular smooth muscle cell to nitric oxide/cGMP-related compounds is increased in HS rings and is associated with a greater activation of the repolarizing BKCa channels. Such changes might counterbalance enhanced contractile response to membrane depolarization and thus participate in maintenance of arterial pressure in the present model of early and long-term HS feeding in rats.