1,247 research outputs found
Platinum(II), palladium(II), nickel(II), and gold(I) complexes of the âelectrospray-friendlyâ thiolate ligands 4-SCâ HâN- and 4-SCâHâOMe-
The series of platinum(II), palladium(II), and nickel(II) complexes [MLâ(dppe)] [M = Ni, Pd, Pt; L = 4-SCâ
HâN or 4-SCâHâOMe; dppe = PhâPCHâCHâPPhâ] containing pyridine-4-thiolate or 4-methoxybenzenethiolate ligands, together with the corresponding gold(I) complexes [AuL(PPh3)], were prepared and their electrospray ionization mass spectrometric behavior compared with that of the thiophenolate complexes [M(SPh)â(dppe)] (M = Ni, Pd, Pt) and [Au(SPh)(PPhâ)]. While the pyridine-4-thiolate complexes yielded protonated ions of the type [M + H]+ and [M + 2H]ÂČ+ ions in the Ni, Pd, and Pt complexes, an [M + H]+ ion was only observed for the platinum derivative of 4-methoxybenzenethiolate. Other ions, which dominated the spectra of the thiophenolate complexes, were formed by thiolate loss and aggregate formation. The X-ray crystal structure of [Pt(SCâHâOMe-4)â(dppe)] is also reported
TiO2 film properties as a function of processing temperature, volume 3
Thin film TiO2 was produced at 150 C by chemical vapor deposition using hydrolysis of tetraisopropyl titanate. Films were amorphous as grown, but annealing in air caused crystallization, with anatase formed beginning at 350 C and rutile at 700 C. Density and index of refraction increased substantially with increasing anneal temperature, while etch susceptibility in HF and H2SO4 decreased. Comparison with literature data showed two groups of processes. One group yields films having properties that gradually approach those of rutile with increasing process temperature. The other group gives rutile directly at moderate temperatures. Deposition of amorphous film followed by etching and annealing is suggested as a means for pattern definition
Spin-orbit coupling and phase-coherence in InAs nanowires
We investigated the magnetotransport of InAs nanowires grown by selective
area metal-organic vapor phase epitaxy. In the temperature range between 0.5
and 30 K reproducible fluctuations in the conductance upon variation of the
magnetic field or the back-gate voltage are observed, which are attributed to
electron interference effects in small disordered conductors. From the
correlation field of the magnetoconductance fluctuations the phase-coherence
length l_phi is determined. At the lowest temperatures l_phi is found to be at
least 300 nm, while for temperatures exceeding 2 K a monotonous decrease of
l_phi with temperature is observed. A direct observation of the weak
antilocalization effect indicating the presence of spin-orbit coupling is
masked by the strong magnetoconductance fluctuations. However, by averaging the
magnetoconductance over a range of gate voltages a clear peak in the
magnetoconductance due to the weak antilocalization effect was resolved. By
comparison of the experimental data to simulations based on a recursive
two-dimensional Green's function approach a spin-orbit scattering length of
approximately 70 nm was extracted, indicating the presence of strong spin-orbit
coupling.Comment: 8 pages, 7 figure
Rooperol, an inhibitor of cytokine synthesis, decreases the respiratory burst in human and rat leukocytes and macrophages
Luminol-enhanced chemiluminescence was measured in fresh whole human blood, or human neutrophils isolated from heparinized blood, human alveolar macrophages and rat alveolar macrophages stimulated with bacterial endotoxin (LPS). Tetraacetate esters of rooperol, a dicatechol showing anticytokine activity, added to cells simultaneously with LPS inhibited the respiratory burst. The effective concentrations of rooperol were in the range of 1-10 ÎŒM depending on cell type and corresponded well with inhibition of nitric oxide production by rat alveolar macrophages. Thus rooperol may reduce some effects of excessive phagocytic activity and inflammatory reaction but by quenching free radicals production may also diminish the resistance to bacterial infections
Predicting success in medical school: a longitudinal study of common Australian student selection tools
Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0
International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and
reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver
(http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.Background: Medical student selection and assessment share an underlying high stakes context with the need for
valid and reliable tools. This study examined the predictive validity of three tools commonly used in Australia:
previous academic performance (Grade Point Average (GPA)), cognitive aptitude (a national admissions test), and
non-academic qualities of prospective medical students (interview).
Methods: A four year retrospective cohort study was conducted at Flinders University Australia involving 382
graduate entry medical students first enrolled between 2006 and 2009. The main outcomes were academic and
clinical performance measures and an indicator of unimpeded progress across the four years of the course.
Results: A combination of the selection criteria explained between 7.1 and 29.1 % of variance in performance
depending on the outcome measure. Weighted GPA consistently predicted performance across all years of the
course. The national admissions test was associated with performance in Years 1 and 2 (pre-clinical) and the
interview with performance in Years 3 and 4 (clinical). Those students with higher GPAs were more likely to have
unimpeded progress across the entire course (OR = 2.29, 95 % CI 1.57, 3.33).
Conclusions: The continued use of multiple selection criteria to graduate entry medical courses is supported, with
GPA remaining the single most consistent predictor of performance across all years of the course. The national
admissions test is more valuable in the pre-clinical years, and the interview in the clinical years. Future selections
research should develop the fledgling research base regarding the predictive validity of the Graduate Australian
Medical School Admissions Test (GAMSAT), the algorithms for how individual tools are combined in selection, and
further explore the usefulness of the unimpeded progress index
Supercurrent in Nb/InAs-Nanowire/Nb Josephson junctions
We report on the fabrication and measurements of planar mesoscopic Josephson
junctions formed by InAs nanowires coupled to superconducting Nb terminals. The
use of Si-doped InAs-nanowires with different bulk carrier concentrations
allowed to tune the properties of the junctions. We have studied the junction
characteristics as a function of temperature, gate voltage, and magnetic field.
In junctions with high doping concentrations in the nanowire Josephson
supercurrent values up to 100\,nA are found. Owing to the use of Nb as
superconductor the Josephson coupling persists at temperatures up to 4K. In all
junctions the critical current monotonously decreased with the magnetic field,
which can be explained by a recently developed theoretical model for the
proximity effect in ultra-small Josephson junctions. For the low-doped
Josephson junctions a control of the critical current by varying the gate
voltage has been demonstrated. We have studied conductance fluctuations in
nanowires coupled to superconducting and normal metal terminals. The
conductance fluctuation amplitude is found to be about 6 times larger in
superconducting contacted nanowires. The enhancement of the conductance
fluctuations is attributed to phase-coherent Andreev reflection as well as to
the large number of phase-coherent channels due to the large superconducting
gap of the Nb electrodes.Comment: 5 Figure, submitted to Journal of Applied Physic
Diagnosis and outcome of oesophageal Crohn's disease
BACKGROUND AND AIMS:
Crohn's disease (CD) can involve any part of the gastrointestinal tract. We aimed to characterize clinical, endoscopic, histologic features and treatment outcomes of CD patients with oesophageal involvement.
METHODS:
We collected cases through a retrospective multicentre European Crohn's and Colitis Organisation CONFER [COllaborative Network For Exceptionally Rare case reports] project. Clinical data were recorded in a standardized case report form.
RESULTS:
A total of 40 patients were reported [22 males, mean (±SD, range) age at oesophageal CD diagnosis: 25 (±13.3, 10-71) years and mean time of follow-up: 67 (±68.1, 3-240) months]. Oesophageal involvement was established at CD diagnosis in 26 patients (65%) and during follow-up in 14. CD was exclusively located in the oesophagus in 2 patients. Thirteen patients (32.2%) were asymptomatic at oesophageal disease diagnosis. Oesophageal strictures were present in 5 patients and fistulizing oesophageal disease in one. Eight patients exhibited granulomas on biopsies. Proton-pump inhibitors (PPIs) were administered in 37 patients (92.5%). Three patients underwent endoscopic dilation for symptomatic strictures and none oesophageal-related surgery. Diagnosis in pre-established CD resulted in treatment modifications in 9/14 patients. Clinical remission of oesophageal disease was seen in 33/40 patients (82.5%) after a mean time of 7 (±5.6, 1-18) months. Follow-up endoscopy was performed in 29/40 patients and 26/29 (89.7%) achieved mucosal healing.
CONCLUSION:
In this case series the endoscopic and histologic characteristics of isolated oesophageal CD were similar to those reported in other sites of involvement. Treatment was primarily conservative, with PPIs administered in the majority of patients and modifications in pre-existing IBD-related therapy occurring in two thirds of them. Clinical and endoscopic remission was achieved in more than 80% of the patients.info:eu-repo/semantics/publishedVersio
Development and Validation of Makeup and Sexualized Clothing Questionnaires
Background: Body acceptance programs on college campuses indicated that collegiate women often report feeling pressure to dress in a sexualized manner, and use makeup to enhance beauty. Currently, no quantitative measures exist to assess attitudes and daily behaviors that may arise in response to perceived pressure to wear makeup or dress in a provocative manner. The goal of the current studies was to develop brief self-report questionnaires aimed at assessing makeup and sexualized clothing use and attitudes in young women.
Methods: An exploratory factor analysis in a sample of 403 undergraduate women was used in Study 1 to create items to measure the pressure women feel to wear makeup and sexualized clothing. A confirmatory factor analysis (N = 153) was used in Study 2 to confirm the factor structure found in Study 1. An incremental validity analysis was also conducted in Study 2. Across both studies, participants completed online questionnaires.
Results: In Study 1, items were developed for two questionnaires to assess perceived pressure to wear makeup and discomfort when not wearing makeup, and perceived pressure to wear sexualized clothing, and body image concerns with regards to sexualized clothing. The exploratory factor analyses revealed Unconfident and Unease scales for the Makeup Questionnaire (MUQ) and Body Dissatisfaction and Pressure scales for the Sexualized Clothing Questionnaire (SCQ). In Study 2, the confirmatory factor analyses confirmed the factor structure for the MUQ and SCQ. The incremental validity analysis revealed that these measures can be used to predict self-objectification and shape and weight concern in women.
Conclusion: These studies provide preliminary support for the factor structure of two novel questionnaires aimed at assessing perceived pressure to wear makeup and sexualized clothing
The role of marine reserves in achieving sustainable fisheries (One contribution of 15 to a Theme Issue 'Fisheries: a Future?')
Many fishery management tools currently in use have conservation value. They are designed to maintain stocks of commercially important species above target levels. However, their limitations are evident from continuing declines in fish stocks throughout the world. We make the case that to reverse fishery declines, safeguard marine life and sustain ecosystem processes, extensive marine reserves that are off limits to fishing must become part of the management strategy. Marine reserves should be incorporated into modern fishery management because they can achieve many things that conventional tools cannot. Only complete and permanent protection from fishing can protect the most sensitive habitats and vulnerable species. Only reserves will allow the development of natural, extended age structures of target species, maintain their genetic variability and prevent deleterious evolutionary change from the effects of fishing. Species with natural age structures will sustain higher rates of reproduction and will be more resilient to environmental variability. Higher stock levels maintained by reserves will provide insurance against management failure, including risk-prone quota setting, provided the broader conservation role of reserves is firmly established and legislatively protected. Fishery management measures outside protected areas are necessary to complement the protection offered by marine reserves, but cannot substitute for it
Magnetotransport properties of a polarization-doped three-dimensional electron slab
We present evidence of strong Shubnikov-de-Haas magnetoresistance
oscillations in a polarization-doped degenerate three-dimensional electron slab
in an AlGaN semiconductor system. The degenerate free carriers
are generated by a novel technique by grading a polar alloy semiconductor with
spatially changing polarization. Analysis of the magnetotransport data enables
us to extract an effective mass of and a quantum
scattering time of . Analysis of scattering processes helps
us extract an alloy scattering parameter for the AlGaN material
system to be
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