bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and magnetic properties of Zn1−xCoxO nanorods
Authors: Yang L. W. , Wu X. L. , Qiu T. , Siu G. G. , Chu Paul K.
Published: April 2006

Magnetic Zn1−xCoxO nanorods were fabricated via direct hydrothermal synthesis. The measurements of x-ray diffraction, x-ray photoemission spectroscopy, and optical absorption spectra demonstrate the presence of cobalt in the +2 state in a tetrahedral crystal field, which indicates that Co ions have been doped into the nanorods. The observations of morphology and microstructure reveal that the Zn1−xCoxO nanorods grow along the [0002] direction through Ostwald ripening not only competing with but being assisted by oriented attachment. The field dependence of magnetization (M-H curves) of the Zn1−xCoxO nanorods measured at 300K shows their ferromagnetic characteristics. The coercive fields (Hc) were obtained to be 98 and 36Oe for nominal x=0.029 and 0.056, respectively. Our experimental results provide one effective method for fabrication of transition metal doped ZnO nanostructures with room-temperature ferromagnetism by direct chemical synthesis.
Atomic scale characterization of layered ternary Cr2AlC ceramic
Authors: Lin Zhijun , Zhuo Mujin , Zhou Yanchun , Li Meishuan , Wang Jingyang
Published: April 2006

Cr 2 Al C is a recently developed layered ternary carbide. In this work, the atomic scale microstructure is reported. The layer stacking sequence of Cr and Al atoms has been clearly resolved. The atomic scale characterizations were realized by means of high resolution transmission electron microscopy and Z-contrast scanning transmission electron microscopy. Furthermore, electron energy loss spectroscopic analysis revealed that the Cr–C bonds in Cr2AlC are characterized by a strong σ bonding.
Adding salt to an aqueous solution of t-butanol: Is hydrophobic association enhanced or reduced?
Authors: Paschek Dietmar , Geiger Alfons , Hervé Momo Jeufack , Suter Dieter
Published: April 2006

Recent neutron scattering experiments on aqueous salt solutions of amphiphilic t-butanol by Bowron and Finney [Phys. Rev. Lett. 89, 215508 (2002); J. Chem. Phys. 118, 8357 (2003)] suggest the formation of t-butanol pairs, bridged by a chloride ion via O–H⋯Cl− hydrogen bonds, leading to a reduced number of intermolecular hydrophobic butanol-butanol contacts. Here we present a joint experimental/theoretical study on the same system, using a combination of molecular dynamics (MD) simulations and nuclear magnetic relaxation measurements. Both MD simulation and experiment clearly support the more classical scenario of an enhanced number of hydrophobic contacts in the presence of salt, as it would be expected for purely hydrophobic solutes. [T. Ghosh et al., J. Phys. Chem. B 107, 612 (2003)]. Although our conclusions arrive at a structurally completely distinct scenario, the molecular dynamics simulation results are within the experimental error bars of the Bowron and Finney data.
Effects of temperature and flux on oxygen bubble formation in Li borosilicate glass under electron beam irradiation
Authors: Ollier Nadège , Rizza Giancarlo , Boizot Bruno , Petite Guillaume
Published: April 2006

Oxygen bubble formation and evolution under a 300keV electron beam are analyzed in a Li borosilicate glass under different irradiation conditions: temperature, flux, and dose. Oxygen bubbles are observed to form in a delimited flux and temperature region with a threshold requirement. This region ranges between 100 and 300°C for the temperatures and between 1019 and 1021em−2s−1 for the electron fluxes. In situ transmission electron microscopy allows the bubble evolution kinetics to be described as a four-step process. An incubation step is followed by a growth phase of sigmoid type. For high values of temperature and/or flux the saturation growth and the subsequent dissolution of the bubbles are also observed. The bubble evolution kinetics can be explained by considering the production and diffusion mechanisms of the molecular oxygen O2 as a function of the temperature and the electron flux.
Magnetic and transport properties in the Ti doped cobaltite Ca3Co4−xTixO9 (⩽x⩽0.8) single crystals
Authors: Zhao B. C. , Sun Y. P. , Song W. H.
Published: April 2006

Single crystals of Ca3Co4−xTixO9 (x=0, 0.2, 0.4, 0.6, and 0.8) are grown by flux growth technique. The effect of Ti doping at Co site on magnetic and transport properties is studied. All samples show Curie-Weiss behavior at temperatures above 50K except for the x=0.8 sample, and the effective magnetic moment μeff increases with increasing Ti content. The free-doped sample Ca3Co4O9 shows a ferrimagnetic transition at 19K. However, a spin-glass transition at Tf(∼20K) appears for the Ti doped samples and the transition temperature Tf shifts to higher temperature as the Ti content increases. The magnetic moment values M at Tf and 5K under the applied field of 4.5T increase with increasing Ti doping content. The variation of the magnetic properties may be related to the induced extra Co2+ ions in the CoO2 layer by substituting Ti4+ for Co3+. The resistivity ρ of the x=0, 0.2, 0.4, and 0.6 samples shows metalliclike behavior at high temperatures and a broad metal-insulator (M-I) transition appears as the temperature decreases to a certain value Tmin. The value of resistivity and the ratio of ρ5K∕ρ300K increase with increasing Ti content. The results are discussed according to the decrease of charge carrier concentration in the samples, which is confirmed by the Hall coefficient measurement. For the x=0.8 sample, there exists another M-I transition in the vicinity of 269K, which is suggested to originate from the spin-state transition of Co3+ or Co4+ ions.
Spectroscopic study of ablation and recombination processes in a laser-produced ZnO plasma
Authors: Namba S. , Nozu R. , Takiyama K. , Oda T.
Published: April 2006

Characteristics of laser-produced ZnO plasmas have been investigated by spectroscopic observations. In particular, the ablation dynamics and recombination process in vacuum or gas atmospheres (helium or oxygen) were studied on the basis of atomic physics. During and immediately after a laser irradiation, plasma parameters, such as electron temperature and electron density, were deduced from continuum and line spectra. In addition, the expansion velocities of ions and atoms were determined by time-of-flight transients of the emission spectra. As for the neutralization process of the expanding plasmas in vacuum, it was found that the radiative recombination dominated the plasma neutralization process. On the other hand, long-lived bright emissions that had a roughly spherical shape were observed in a helium atmosphere. This can be explained by the scattering of particles ejected from the target and rapid plasma cooling due to the collision with an ambient gas. Thus, the three-body recombination responsible for the intense emissions played an important role for electron-ion recombination. Moreover, it was found that a charge exchange recombination between He+ and Zn occurred near the target surface in helium. Although similar results were obtained in an oxygen atmosphere, the peak intensities were much higher than those in helium, implying that the additional cooling associated with the inherent properties of molecules may significantly influence the plasma neutralization.
Coulomb and radiation screening in photoconductive terahertz sources
Authors: Kim Dae Sin , Citrin D. S.
Published: April 2006

We distinguish the screening contributions due to the Coulomb and radiation parts of the electromagnetic field subsequent to the ultrafast photogeneration of electron-hole pairs in photoconductive GaAs terahertz (THz) sources. We employ the Monte Carlo method self-consistently including the Maxwell equations to study the effects of the excitation-spot size and excitation level on the emitted THz radiation, and find for a range of reasonable excitation levels an excitation-spot diameter of ∼100μm as the crossover point beyond which radiation effects dominate screening.
Stability of Ti in NaAlH4
Authors: Løvvik O. M. , Opalka S. M.
Published: April 2006

There has been confusion which external reference should be used for predicting ground state Ti substitution enthalpies in NaAlH4: element gaseous atomic states or standard states. It is proposed instead to use all the relevant product phases for the Ti-enhanced sodium alanate system as internal reference states. The results are similar to when external reference element standard states are used: Ti doping is unstable in NaAlH4, and substitution on the Al sublattice is the least unfavorable. Substitution near the surface is more favorable than in the bulk, thus metastable Ti substitution may occur close to interfaces, grain boundaries, or defects.
Ab initio study of the Cr2AlC(0001) surface
Authors: Sun Zhimei , Ahuja Rajeev
Published: April 2006

Using an ab initio total energy method, we have calculated the surface energy and surface stress of Cr2AlC(0001) with the configuration of the top layer as Al[(0001)Al], Cr[(0001)Cr], and C[(0001)C] atoms, respectively. Both the surface energy and surface stress of (0001)Cr are very close to (0001)C. While those of (0001)Al are the lowest, suggesting that this surface configuration is the most stable one. Furthermore, the interplanar relaxation does not have any obvious effect on the surface energy, while the surface stress decreased dramatically under layer relaxation. The Cr-C bond length in the surface layer contracted by >5%, and the bond contraction for Cr-Al is <1.5%, showing that the bond strength in the surface layer is higher than that in the bulk region.
PAR DES TRAITS
D'HENRI MICHAUX: LA MÉMOIRE PICTURALE DU SIGNE
Authors: Poncelet Dominique
Published: April 2006

Dans
Par des traits
, le poète et peintre Henri Michaux dresse une critique acerbe du langage verbal, dont la structure selon lui nous emprisonne et nous paralyse. Pour contrer ces défauts des langues, il préconise la création de signes neufs qui pourraient nous libérer. L'objectif de cet article est de définir ce que sont ces signes que Michaux aurait voulu créer et de montrer en quoi l'art pictural, mais aussi la poésie, sont à même de forger ces signes. Dans
Par des traits
, Michaux décrit ces signes en revenant au moment de leur émergence, là où, comme des dessins, ils existent encore sous forme de traits et sont sur le point de prendre sens dans une communauté. Dans leur moment pictural, ces signes portent donc encore en eux la force et l'énergie du geste qui les a tracés. Et comme ils ne sont encore assujettis à aucune codification, il leur faut, pour être déchiffrés, un groupe de lecteurs qui acceptent de collaborer pour leur donner sens. Au sein des langues verbales, la poésie possède le pouvoir de réinstituer des signes en les rappelant à leur mémoire picturale.
Functional Limitations in Thiamine Deficiency Neuropathy: FIM Score Improvement With Treatment
Authors: Norio Ohkoshi , Tsuneo Fujita , Akito Hayashi
Published: April 2006

We studied the functional limitations of the activities of daily living and the effect of treatment on 8 patients with thiamine deficiency neuropathy. Functional activities of daily living were evaluated using the functional independence measure whose scores were obtained before and after high-dose vitamin B1 therapy. In the pretreatment evaluation, the lowest mean score was that of in locomotion (stairs), followed by locomotion (walk-wheelchair), transfers (tub-shower), bathing, dressing the lower body, toileting, transfers (bed-chair-wheelchair), and transfers (toilet), in that order. This tendency was also observed after treatment. The most remarkable therapeutic efficacy was observed in locomotion (walk-wheelchair), followed by transfers (tub-shower), locomotion (stairs), dressing the lower body, and toileting, in that order. Every action reflects the motor ability of the lower extremities. Thiamine deficiency neuropathy should be assessed routinely not only by medical evaluation of clinical symptoms or laboratory studies but also by functional evaluation that reflects each patient's disability.
Myeloneuropathic Presentation of Spinal Epidural Lipomatosis
Authors: Izadyar Shahram , Kwan Justin Y. , Harati Yadollah
Published: April 2006

Spinal epidural lipomatosis (SEL) is accumulation of unencapsulated fat tissue within the epidural space of the spinal canal. The most common cause of SEL is corticosteroid therapy, whereas most of the non–corticosteroid-dependent cases are idiopathic. If unrecognized, it may result in diagnostic confusion with other neuropathic or myelopathic conditions. We report 2 cases of SEL. The first case is of a 30-year-old man who received corticosteroid therapy for an acute and probably immune-mediated demyelinating process. Subsequently, the addition of compressive effects of SEL resulted in diagnostic confusion and initial workup at other centers for spinal cord malignancy and vascular malformation. The patient's symptoms improved after decompression surgery. The second case is of a 63-year-old woman with a history of type 1 diabetes mellitus that presented with increasing numbness in the lower extremities. She was initially diagnosed with diabetic neuropathy; however, the presence of myelopathic signs led to further investigation and diagnosis of SEL. Decompression surgery resulted in improvement of symptoms.
Medial Sural Cutaneous Nerve Biopsy
Authors: Thornton James Fallon , Wang Jason , Riley Christopher Jerron
Published: April 2006

This paper describes indications, preoperative preparation, operative technique, and postoperative care for an adaptation of a commonly performed, outpatient neurology procedure, the sural nerve biopsy. We performed a chart review on 12 patients, with follow-ups ranging from 6 to 26 months, treated by the PI (J.F.T.) over 3 years, and only 1 noted complication (delayed wound healing in a steroid-dependent person). All procedures were performed in an operating room setting under local anesthetic with standby intravenous sedation. We provide a stepwise procedure description of this technique that can be performed with very low morbidity in an outpatient, minor procedure setting.
A case of juvenile hyaline fibromatosis
Authors: YAYLI Savaş , UNCU Sibel , ALPAY Köksal , YILDIZ Kadriye , ÇIMŞIT Gülseren , BAHADIR Sevgi
Published: April 2006

Juvenile hyaline fibromatosis (JHF) is a rare, autosomally‐recessive disease characterized by papulonodular skin lesions, soft tissue masses, joint contractures, gingival hypertrophy and osteolytic bone lesions. Its onset is in infancy or early childhood. The most commonly affected sites are the nose, chin, ears, scalp, back and knees. The accumulation of an amorphous, hyaline material is typical in the skin and the other organs. Herein, we report a 14‐month‐old boy who presented with confluent pink papules on the paranasal folds and the chin, and nodular lesions on the periauricular and perianal regions. He had gingival hypertrophy and contractures of the shoulders, knees and elbows. He also had third‐degree consanguineous parents. Histopathological studies confirmed the diagnosis of JHF with the presence of increased numbers of fibroblasts embedded in a hyalinized connective tissue stroma.
Immunohistochemical Detection of P‐Glycoprotein (Clone C494) in Canine Mammary Gland Tumours
Authors: Petterino C. , Rossetti E. , Bertoncello D. , Martini M. , Zappulli V. , Bargelloni L. , Castagnaro M.
Published: April 2006

Elevated levels of P‐glycoprotein have been reported in multidrug‐resistant tumours in both humans and dogs. In the present study, we investigated the expression of P‐glycoprotein in 57 canine mammary gland tumours, 10 mammary gland hyperplasia and seven normal mammary glands by immunohistochemistry. Tissue sections were incubated with an anti‐Pgp monoclonal antibody and visualized with En Vision‐DAB polymer. Normal and hyperplastic mammary tissues were negative or showed slight cytoplasmic immunoreactivity. Neoplastic cells in benign mammary tumours showed diffuse cytoplasmic staining, in contrast to malignant tumours that showed mainly a membranous staining pattern for Pgp (C494). We observed statistically significant differences among all the different groups of tissues analysed except for benign tumours versus hyperplasia (P = 0.221). Receiver‐operating characteristic analysis showed that the best cut‐off point to differentiate the threshold to differentiate negative from positive tissue samples was 18.40% of immunostained cells. These results provide a first indication that routine evaluation of Pgp expression in canine mammary gland tumours, taking into consideration a cut‐off point for positivity, may be useful for selecting cases for chemotherapy.
Detection of Salmonella spp. in Stray Dogs in Bursa Province, Turkey: First Isolation of Salmonella Corvallis from Dogs
Authors: Kocabiyik A. L. , Cetin C. , Dedicova D.
Published: April 2006

The prevalence and antimicrobial sensitivity of Salmonella spp. in stray dogs in Bursa province, Turkey were determined from a total of 82 faecal samples by bacteriological methods. Of the dogs, nine (11%) were positive for salmonellae‐carrying. All Salmonella isolates were serotyped as S. Corvallis, and were sensitive to amoxycillin/clavulanic acid, ampicillin, cephalothin, chloramphenicol, enrofloxacin, gentamicin, kanamycin, nalidixic acid, neomycin, oxytetracycline and trimethoprim/sulphamethoxazole, while 66.7% of them were resistant to streptomycin. It was concluded that stray dogs could be an important carrier of salmonellae as well as a source of human salmonellosis in Turkey. Additional studies are needed to clarify the epidemiological relationship between S. Corvallis isolated from dogs and humans with regard to public health. This is the first report on the isolation of S. Corvallis from dogs in the country.
Hand dermatitis among Korean nursing students
Authors: Smith Derek R , Choe Myoung‐Ae , Jeong Jae Sim , An Gyeong Ju , Chae Young Ran , Jeon Mi Yang
Published: April 2006

The aim of this study was to conduct the first epidemiological investigation of hand dermatitis among Korean nursing students. We used a previously validated questionnaire survey, which was translated into Korean and given to 270 students from a university‐based nursing school in Seoul. A total of 202 questionnaires were received. The students’ hand dermatitis prevalence ranged from 6.9% in the first year to 22.9% in the fourth year. Logistic regression indicated that students with systemic allergies were 4.2 times as likely to suffer from hand dermatitis. Year of study and living arrangements were also shown to have statistically significant correlations with hand dermatitis. Overall, this study suggests that hand dermatitis might be less prevalent among Korean nursing students when compared with their international counterparts. However, the identification of systemic allergies as a significant risk factor was consistent with previous reports from other countries.
Clinical predictors for the detection of community‐acquired pneumonia in adults as a guide to ordering chest radiographs
Authors: OKIMOTO Niro , YAMATO Kenji , KURIHARA Takeyuki , HONDA Yoshihiro , OSAKI Kohichi , ASAOKA Naoko , FUJITA Kazue , OHBA Hideo
Published: April 2006

Objective:  To identify sensitive clinical predictors for the detection of community‐acquired pneumonia in adults as a guide to when to order a CXR.

Methods:  In total, 79 outpatients presenting with at least one of the following clinical features of pneumonia: fever, cough, sputum, chest pain, dyspnoea and coarse crackles and who underwent CXR to detect pneumonia were examined retrospectively. The relationship between these clinical features and the presence of pneumonia on CXR was determined.

Results:  A total of 24 patients (30.4%) had radiological evidence of pneumonia. In total, 22 presented with four clinical signs: fever, cough, sputum and coarse crackles. The sensitivity and the specificity of detecting pneumonia based on these four clinical signs mentioned was 91.7% and 92.7%, respectively.

Conclusions:  As a diagnostic strategy, the ordering of CXR to confirm a diagnosis of community‐acquired pneumonia in adults is recommended when patients have the following four clinical signs: fever, cough, sputum and coarse crackles.
Visual function following transpupillary thermotherapy with adjusted laser parameters for the treatment of exudative age‐related macular degeneration: a pilot study
Authors: Tranos Paris , Peter Neena M , Nath Remin , Singh Minu V , Wren Siobhan , Dimitrakos S , Rassam Sal , Kon Chee
Published: April 2006

Abstract

Purpose:  To evaluate the efficacy of transpupillary thermotherapy (TTT) using adjusted laser parameters for the treatment of choroidal neovascularization (CNV) secondary to age‐related macular degeneration.

Methods:  TTT was performed on patients with CNV using a diode laser (810 nm) for 60 s in a subthreshold manner. Power settings were varied between 460 and 1200 mW, depending on lesion size, presence of pigment epithelial detachment and the amount of fundal pigmentation and subretinal fluid. LogMAR visual acuity, contrast sensitivity (Pelli‐Robson) and metamorphopsia (Amsler chart) were assessed prior to and 6 months following treatment. Subjects also self‐administered the National Eye Institute 25‐Item Visual Function Questionnaire.

Results:  Thirty occult/minimally classic and eight predominantly classic membranes were treated with TTT. At 6 months, absence or significant reduction of fluorescein leakage was observed in 20 (53%) patients. Stabilization of vision (loss of less than 15 letters) was observed in 25/30 (83%) eyes with occult/minimally classic CNV and 5/8 (63%) eyes with predominantly classic CNV. Improvement of contrast sensitivity was noted in 15 (35%) eyes, in 10 (26%) eyes it remained unchanged and in 13 (34%) eyes it deteriorated. There was no statistically significant effect of TTT on the National Eye Institute 25‐Item Visual Function Questionnaire composite or subscale scores.

Conclusions:  TTT using adjusted parameters depending on fundal characteristics appears to be effective in stabilizing subjective and objective visual ability in a considerable number of patients with subfoveal CNV due to age‐related macular degeneration. Larger‐scale studies are required to confirm the benefit of this technique as opposed to the natural history of occult CNV.
Advances in introgression technologies for precision breeding within the Lolium ‐ Festuca complex
Authors: HUMPHREYS M W , CANTER P J , THOMAS H M
Published: April 2006

The anticipated complexity of multifunctional grasslands with environment‐friendly and sustainable management practices demands better understanding of traits, their interactions, and their genetic control. Intergeneric hybrids between closely related Lolium and Festuca species are being used to broaden the gene pool and provide the plant breeder with options to combine complementary traits aimed at high quality but more robust grass varieties for the future. New techniques in introgression mapping provide opportunities for precision breeding whereby desirable gene combinations transferred from one species into another are selected preferentially, with the exclusion of deleterious alien genes. The close homology between genomes of Lolium and Festuca species allows high levels of chromosome pairing and recombination. Using genomic in situ hybridisation (GISH) on Lolium/Festuca hybrids and their derivatives, recombination between Lolium and Festuca chromosomes is observed at any point along the chromosome. The system provides unlimited access to any combination of Lolium and Festuca DNA sequence. Moreover, genes transferred between homoeologous chromosome sites are expected to function normally at their new locations. Alien chromosome segments may be reduced in size by further recombination events thereby reducing linkage drag. Molecular markers such as AFLPs, SSRs, SNPs, or RFLPs are being targeted to genes of interest to allow their selection through different generations in plant breeding programmes. Relatively simple PCR‐based marker systems are used for specific traits as breeders' toolkits in plant breeding programmes.
Seasonal differences in mineral content, distribution and leakage of sweet pepper seeds
Authors: XU GUOHUA , KAFKAFI UZI
Published: April 2006

Pepper seed quality is sensitive to variations in climatic conditions during seed development, which might be associated with accumulation, distribution and leakage of mineral elements from the seeds. This was examined in hybrid seeds of sweet pepper (Capsicum annuum L. cv.‘Hazera’ 1195) in two experiments during two growing seasons. The mean daily temperature (day/night) and daily total radiation receipt during seed development were 27.9/23.2°C and 8.63 kW m−2 in the summer and 18.3/ 14.9°C and 3.18 kW m−2 in the winter, respectively. Seeds developed in the summer had lower percentage of seedling emergence and leaked a larger portion (45%) of their K content into the water medium than in winter‐developed seeds. Summer seeds accumulated more K and Cl, but less P, Mg, Ca and the weight ratio of linoleic acid to oleic acid was lower than in the winter seeds. The season did not significantly affect N, S and total fatty acids. The most abundant element on the seed coat surface was K in the summer and Ca in the winter seeds. The cotyledon and endosperm of the summer seeds contained relatively higher ratios of K and Ca and lower ratios of P and Mg than the winter seeds. Transportation of mineral nutrients appeared to be involved in the effect of heat and moisture stresses on emergence quality of the pepper seeds.
A 5‐year comparison of overwintering polyphagous predator densities within a beetle bank and two conventional hedgebanks
Authors: COLLINS K L , BOATMAN N D , WILCOX A , HOLLAND J M
Published: April 2006

Overwintering polyphagous predator density and composition was compared within a mid‐field overwintering refuge (“beetle bank”) and two conventional hedgebanks over a 5‐year period. During the study predator densities in the beetle bank were similar to or greater than those in the conventional hedgebanks. Whilst predator densities remained relatively stable in both of the hedgebanks over time, densities fluctuated significantly within the beetle bank. Many of the species recorded on the beetle bank are considered to be important predators of cereal aphids. The results are discussed in terms of the implications of creating such a habitat for the biological control of cereal aphids.
STRATEGY SPACE EXPLORATION OF A MULTI-AGENT MODEL FOR THE LABOR MARKET
Authors: DE GRANDE PABLO , EGUIA MANUEL
Published: April 2006

We present a multi-agent system where typical labor market mechanisms emerge. Based on a few simple rules, our model allows for different interpretative paradigms to be represented and for different scenarios to be tried out. We thoroughly explore the space of possible strategies both for those unemployed and for companies and analyze the trade-off between these strategies regarding global social and economical indicators.
SOCIAL HIERARCHIES WITH AN ATTRACTIVE SITE DISTRIBUTION
Authors: NAUMIS G. G. , DEL CASTILLO-MUSSOT M. , PÉREZ L. A. , VÁZQUEZ G. J.
Published: April 2006

We reinvestigate the model of Bonabeau et al.1 of self-organizing social hierarchies by including a distribution of attractive sites. Agents move randomly except in the case where an attractive site is located in its neighborhood. We find that the transition between an egalitarian society at low population density and a hierarchical one at high population density strongly depends on the distribution and percolation of the valuable sites. We also show how agent diffusivity is closely related to social hierarchy.
SOME ASYMPTOTIC METHODS FOR STRONGLY NONLINEAR EQUATIONS
Authors: HE JI-HUAN
Published: April 2006

This paper features a survey of some recent developments in asymptotic techniques, which are valid not only for weakly nonlinear equations, but also for strongly ones. Further, the obtained approximate analytical solutions are valid for the whole solution domain. The limitations of traditional perturbation methods are illustrated, various modified perturbation techniques are proposed, and some mathematical tools such as variational theory, homotopy technology, and iteration technique are introduced to overcome the shortcomings.

In this paper the following categories of asymptotic methods are emphasized: (1) variational approaches, (2) parameter-expanding methods, (3) parameterized perturbation method, (4) homotopy perturbation method (5) iteration perturbation method, and ancient Chinese methods.

The emphasis of this article is put mainly on the developments in this field in China so the references, therefore, are not exhaustive.
ANISOTROPIC RESISTIVITY IN Bi2Sr2CaCu2Oy THIN FILMS GROWN ON VICINAL SrTiO3 SUBSTRATES
Authors: TOMA V. , ILONCA G. , RAFFY H.
Published: April 2006

The in-plane resistivity ρab(T) and out-of-plane resistivity ρc(T) are measured for Bi 2 Sr 2 CaCu 2 O 8 superconducting thin films successfully deposited by in situ magnetron RF-sputtering on vicinal (100) SrTiO 3 substrates. Oriented film with c axis inclined with respect to the basal plane by a tilt angle α ≈ 4° was obtained. It was found that for the underdoped region ρab(T) deviates from the high T-linear behavior, which evidences the opening of the pseudogap while from the out-of-plane resistivity measurements, we found that the temperature corresponding to the minimum between metallic and semiconducting behavior appears to reflect the opening of the pseudogap for transport along c axis. We also found that the opening of the pseudogap seen in ρab(T) does not coincide with the pseudogap along c axis.
AN ADAPTIVE FINITE ELEMENT METHOD FOR MODELING SALT DIAPIRISM
Authors: MASSIMI P. , QUARTERONI A. , SCROFANI G.
Published: April 2006

Various types of oil traps have been found to be associated with salt domes in subsurface geology. In this paper the diapiric rise of light salt layers through a denser overburden — the surrounding rocks — is modeled assuming that, in a geological time scale, salt and rocks layers behave like Newtonian fluids. A Lagrangian approach is adopted to track the interface between layers, within the framework of a finite element space discretization. An accurate description of large deformations due to salt movement is achieved using a grid adaptation technique based on geometrical refinement. Different geological cases have been simulated in order to describe the behavior of rocks and estimate the effect on diapiric growth of buoyancy force, differential loading, gravitational gliding and thin-skinned regional extension. Our computational model accounts also for sedimentation and compaction of the overburden.
Growth hormone receptor gene deficiency causes delayed insulin responsiveness in skeletal muscles without affecting compensatory islet cell overgrowth in obese mice
Authors: Robertson Katie , Kopchick John J. , Liu Jun-Li
Published: April 2006

Growth hormone (GH), acting through its receptor (GHR), is essential for somatic growth and development and maintaining metabolic homeostasis. GHR gene-deficient (GHR−/−) mice exhibit drastically diminished insulin-like growth factor-I (IGF-I) levels, proportional growth retardation, elevated insulin sensitivity, and reduced islet β-cell mass. Unlike the liver, which is mostly unaffected by changes in IGF-I level, skeletal muscles express high levels of IGF-I receptor (IGF-IR). The net result of a concurrent deficiency in the actions of both GH and IGF-I, which exert opposite influences on insulin responsiveness, has not been evaluated. We studied insulin-stimulated early responses in the insulin receptor (IR), insulin receptor substrate-1 (IRS-1), and p85 subunit of phosphatidylinositol 3-kinase. Upon in vivo insulin stimulation, skeletal muscles of GHR−/−mice exhibit transient delayed responses in IR and IRS-1 phosphorylation but normal levels of p85 association with IRS-1. This is in contrast to normal/elevated insulin responses in hepatocytes and indicates tissue-specific effects of GHR gene deficiency. In addition to stimulating normal islet cell growth, GH may participate in islet cell overgrowth, which compensates for insulin resistance induced by obesity. To determine whether the islet cell overgrowth is dependent on GH signaling, we studied the response of male GHR−/−mice to high-fat diet (HFD)-induced obesity. After 17 wk on a HFD, GHR−/−mice became more significantly obese than wild-type mice and exhibited increased β-cell mass to a slightly higher extent. These data demonstrate that GH signaling is not required for compensatory islet growth. Thus, in both muscle insulin responsiveness and islet growth compensation, normal levels of GH signals do not seem to play a dominant role.
Epithelial cell polarity and hypoxia influence heme oxygenase-1 expression by heme in renal epithelial cells
Authors: Basireddy Mahesh , Lindsay Jason T. , Agarwal Anupam , Balkovetz Daniel F.
Published: April 2006

Induction of heme oxygenase-1 (HO-1) in renal tubules occurs as an adaptive and beneficial response in acute renal failure (ARF) following ischemia and nephrotoxins. Using an in vitro model of polarized Madin-Darby canine kidney (MDCK) epithelial cells, we examined apical and basolateral cell surface sensitivity to HO-1 induction by heme. Basolateral exposure to 5 μM hemin (heme chloride) resulted in higher HO-1 induction than did apical exposure. The peak induction of HO-1 by basolateral application of hemin occurred between 12 and 18 h of exposure and was dose dependent. Similar cell surface sensitivity to hemin-induced HO-1 expression was observed using a mouse cortical collecting duct cell line (94D cells). Hepatocyte growth factor (HGF) is known to decrease cell polarity of MDCK cells. Following pretreatment with HGF, apically applied hemin gave greater stimulation of HO-1 expression, whereas HGF alone did not induce HO-1. We also examined the effect of hypoxia on hemin-mediated HO-1 induction. MDCK cells were subjected to hypoxia (1% O2) for 24 h to simulate the effects of ischemic ARF. Under hypoxic conditions, both apical as well as basolateral surfaces of MDCK were more sensitive to HO-1 induction by hemin. Hypoxia alone did not induce HO-1 but appeared to potentiate both apical and basolateral sensitivity to hemin-mediated induction. These data demonstrate that the induction of HO-1 expression in polarized renal epithelia by heme is achieved primarily via basolateral exposure. However, under conditions of altered renal epithelial cell polarity and hypoxia, increased HO-1 induction occurs following apical exposure to heme.
Podocyte proteoglycan synthesis is involved in the development of nephrotic syndrome
Authors: Björnson Granqvist A. , Ebefors K. , Saleem M. A. , Mathieson P. W. , Haraldsson B. , Nyström J. Sörensson
Published: April 2006

Proteoglycans (PGs) are important for the glomerular barrier, for cell signaling, and for the anchorage of cells to the glomerular basement membrane. They are, however, complex macromolecules, and their production has not yet been thoroughly investigated in podocytes. In the present study, we studied the biosynthesis of PGs by highly differentiated human podocytes and in rats. The cells were treated with puromycin aminonucleoside (PAN; a nephrosis-inducing agent), steroids (used as primary treatment for nephrotic syndrome), or both. Analysis was made by TaqMan real-time PCR, Western blotting, and by metabolic labeling with35S and3H. We found that podocytes produce versican, syndecan-1, decorin, and biglycan together with the previously known PG syndecan-4, glypican, and perlecan. PAN treatment downregulated the mRNA and the protein expression of both versican (by 24 ± 6%, P < 0.01, for mRNA and by 50% for protein) and perlecan (by 14 ± 5%, P < 0.05, for mRNA and by 50% for protein). The decreased expression was confirmed by studying the glomerular gene expression in rats treated with PAN during a time course study. In addition, puromycin decreased the expression of enzymes involved in the glycosaminoglycan biosynthesis. Steroid treatment decreased perlecan (by 24 ± 3%, P < 0.01) and syndecan-1 expression (by 30 ± 4%, P < 0.01) but increased the expression of decorin 2.5-fold. The observed alterations of PG synthesis induced by PAN may lead to decreased glomerular anionic charge and disturbed podocyte morphology, factors that are important for the development of a nephrotic syndrome.
Caspases and calpain are independent mediators of cisplatin-induced endothelial cell necrosis
Authors: Dursun Belda , He Zhibin , Somerset Hilary , Oh Dong-Jin , Faubel Sarah , Edelstein Charles L.
Published: April 2006

The role of caspases and calpain in cisplatin-induced endothelial cell death is unknown. Thus we investigated whether caspases and calpain are mediators of cisplatin-induced apoptosis and necrosis in endothelial cells. Cultured pancreatic microvascular endothelial (MS1) cells were exposed to 10 and 50 μM cisplatin. Apoptosis or necrosis was determined by Hoechst 33342 and propidium iodide (PI) nuclear staining. Cells treated with 10 μM cisplatin had normal ATP levels, increased caspase-3-like activity, excluded PI and demonstrated morphological characteristics of apoptosis at 24 h. Cells treated with 50 μM cisplatin had severe ATP depletion, increased caspase-3-like activity, and displayed extensive PI staining indicative of necrosis at 24 h. There was a dose-dependent increase in caspase-2-like activity and Smac/DIABLO protein. Calpain activity increased significantly with 50 μM, but not 10 μM cisplatin at 24 h. With 50 μM cisplatin, ATP levels were significantly reduced starting at 18 h, caspase-2- and caspase-3-like activities were significantly increased starting at 18 h, and LDH release started at 8 h with maximum increase at 18–24 h. Calpain activity was not increased before 24 h. The increase in LDH release and the nuclear PI staining with 50 μM cisplatin at 24 h was reduced by either the pancaspase inhibitor, Q-VD-OPH, or the calpain inhibitor, PD-150606. Calpain inhibitor had no effect on caspase-3-like activity. In conclusion, in cisplatin-treated endothelial cells, caspases, the major mediators of apoptosis, can also cause necrosis. A calpain inhibitor protects against necrosis without affecting caspase-3-like activity suggesting that calpain-mediated necrosis is independent of caspase-3.
Research in Cyberspace
Authors: Malinski Violet M.
Published: April 2006

The purpose of this column is twofold. First, Dr. Joyce Griffin-Sobel provides detailed information on search strategies for accessing nursing research in cyberspace. Second, material from an earlier column by Dr. Judy Norris, now retired, is reprinted to provide another look at the significant issues she discussed that are still timely some 7 years later. The column concludes with some of the points raised by Dr. Violet Malinski in her original commentary on Norris’ column. Readers are encouraged to share their experiences with research in cyberspace.
Fables: Ways of Knowing and Understanding Meaning in Nursing
Authors: Milton Constance L.
Published: April 2006

Fables are literary short stories intended to convey a moral maxim for some aspect of human living. Within the discipline of nursing, a fable is a medium by which stories and themes of humanly lived phenomena may be viewed in light of a particular philosophical lens of understanding. The fable offers possibilities for instruction through illuminating fictitious characters and offering notions for what a member of a discipline ought to do. In this article, the author shall present a fable and offer an interpretation from a human becoming perspective for what one ought to do in the discipline of nursing.
Human Becoming Criticism—A Critique of Florczak’s Study on the Lived Experience of Sacrificing Something Important
Authors: Mitchell Gail J.
Published: April 2006

This article presents a critical appraisal of Kristine Florczak’s Parse research method study on the phenomenon of sacrificing something important. The processes of Mitchell’s framework for human becoming criticism—sketching the horizon of understanding, illuminating artistic disclosure, and enhancing the original with artform—are utilized.
Self-Care Operations and Nursing Interventions for Children With Cancer and Their Parents
Authors: Moore Jean Burley , Beckwitt Asher E.
Published: April 2006

As individuals assume more responsibility for their healthcare, nurses need to explore methods to support families’ self-care practices. The purpose of this qualitative study was to: (a) determine what self-care and dependent-care operations children and parents perform to address self-care requisites, and (b) explore nursing interventions to promote operations. Orem’s theory of self-care, theory of self-care deficit, and theory of nursing system were employed. Twenty-seven participants were interviewed about their cancer experiences. Results were that children and parents performed estimative, transitional, and productive operations to meet self-care requisites. Various nursing interventions that promoted these operations were identified. Recommendations were made for further interventions to support families.
The Possibility of Changing Meaning in Light of Space and Place
Authors: Jonas-Simpson Christine
Published: April 2006

The author considers the possibility of changing meaning in light of space and place. Many questions are raised, including a fundamental question: If we simply choose the meaning of space and place based on personal knowing, regardless of the space and place we are in, does space and place really matter with regard to the possibility of changing meaning? Many possibilities of changing meaning in light of space and place are explored, including the influence of personal knowing, new life experiences and understandings, changes to space and place, unique languaging in space and place, imaging space and place, and engaging in the wonder and mystery of space and place beyond this realm. The possibility of changing meaning is significant in that new meanings open doors to different choices—and living choices is living health.
In-depth analysis of the membrane and cytosolic proteome of red blood cells
Authors: Pasini Erica M. , Kirkegaard Morten , Mortensen Peter , Lutz Hans U. , Thomas Alan W. , Mann Matthias
Published: April 2006

In addition to transporting oxygen and carbon dioxide to and from the tissues, a range of other functions are attributed to red blood cells (RBCs) of vertebrates. Diseases compromising RBC performance in any of these functions warrant in-depth study. Furthermore, the human RBC is a vital host cell for the malaria parasite. Much has been learned from classical biochemical approaches about RBC composition and membrane organization. Here, we use mass spectrometry (MS)–based proteomics to characterize the normal RBC protein profile. The aim of this study was to obtain the most complete and informative human RBC proteome possible by combining high-accuracy, high-sensitivity protein identification technology (quadrupole time of flight and Fourier transform MS) with selected biochemical procedures for sample preparation. A total of 340 membrane proteins and 252 soluble proteins were identified, validated, and categorized in terms of subcellular localization, protein family, and function. Splice isoforms of proteins were identified, and polypeptides that migrated with anomalously high or low apparent molecular weights could be grouped into either ubiquitinylated, partially degraded, or ester-linked complexes. Our data reveal unexpected complexity of the RBC proteome, provide a wealth of data on its composition, shed light on several open issues in RBC biology, and form a departure point for comprehensive understanding of RBC functions.
Neuropilin-2 interacts with VEGFR-2 and VEGFR-3 and promotes human endothelial cell survival and migration
Authors: Favier Benoit , Alam Antoine , Barron Pauline , Bonnin Jacques , Laboudie Patricia , Fons Pierre , Mandron Marie , Herault Jean-Pascal , Neufeld Gera , Savi Pierre , Herbert Jean-Marc , Bono Françoise
Published: April 2006

Neuropilin 2 (NRP2) is a receptor for the vascular endothelial growth factor (VEGF) and the semaphorin (SEMA) families, 2 unrelated ligand families involved in angiogenesis and neuronal guidance. NRP2 specifically binds VEGF-A and VEGF-C, although the biological relevance of these interactions in human endothelial cells is poorly understood. In this study, we show that both VEGF-A and VEGF-C induce the interaction of NRP2 with VEGFR-2. This interaction correlated with an enhancement of the VEGFR-2 phosphorylation threshold. Overexpression of NRP2 in primary human endothelial cells promoted cell survival induced by VEGF-A and VEGF-C. In contrast, SEMA3F, another ligand for NRP2, was able to inhibit human endothelial cell survival and migration induced by VEGF-A and VEGF-C. Moreover, a siRNA targeting specifically NRP2 was a potent inhibitor of human endothelial cell migration induced by VEGF-A and VEGF-C. Thus, our data indicate that NRP2 acts as a coreceptor that enhances human endothelial cell biological responses induced by VEGF-A and VEGF-C.
Periodicity of SNP distribution around transcription start sites
Authors: Higasa Koichiro , Hayashi Kenshi
Published: April 2006

Background

Several millions single nucleotide polymorphisms (SNPs) have already been collected and deposited in public databases and these are important resources not only for use as markers to identify disease-associated genes, but also to understand the mechanisms that underlie the genome diversification.

Results

A spectrum analysis of SNP density distribution in the genomic regions around transcription start sites (TSSs) revealed a remarkable periodicity of 146 nucleotides. This periodicity was observed in the regions that were associated with CpG islands (CGIs), but not in the regions without CpG islands (nonCGIs). An analysis of the sequence divergence of the same genomic regions between humans and chimpanzees also revealed a similar periodical pattern in CGI. The occurrences of any mono- or di-nucleotide sequences in these regions did not reveal such a periodicity, thus indicating that an interpretation of this periodicity solely based on the sequence-dependent susceptibility to mutation is highly unlikely.

Conclusion

The periodical patterns of nucleotide variability suggest the location of nucleosomes that are phased at TSS, and can be viewed as the genetic footprint of the chromatin state that has been maintained throughout mammalian evolutionary history. The results suggest the possible involvement of the nucleosome structure in the promoter function, and also a fundamental functional/structural difference between the two promoter classes, i.e., those with and without CGIs.