634 research outputs found
Fan texture of the compound Ba3Co2Fe244O41 pre-aligned in a magnetic field
Samples of the ferrimagnetic material Ba3Co2Fe24O41, pre-aligned in a magnetic field and sintered at various temps., have been examd. for preferred orientation. Schulz's reflection technique and the standardizing method of Holland were used to det. quant. pole figures of several lattice planes. The texture bears a close resemblance to a \"fan texture Degs in which the crystallites have their basal planes parallel to a preferred direction. The sharpness of the texture increases with increasing sintering temp. At 1320 Deg an exaggerated grain growth takes place. Inhomogeneity of the magnetic field throughout the sample results in local differences in orientation. [on SciFinder (R)
Origin of non-exponential relaxation in a crystalline ionic conductor: a multi-dimensional 109Ag NMR study
The origin of the non-exponential relaxation of silver ions in the
crystalline ion conductor Ag7P3S11 is analyzed by comparing appropriate
two-time and three-time 109Ag NMR correlation functions. The non-exponentiality
is due to a rate distribution, i.e., dynamic heterogeneities, rather than to an
intrinsic non-exponentiality. Thus, the data give no evidence for the relevance
of correlated back-and-forth jumps on the timescale of the silver relaxation.Comment: 4 pages, 3 figure
Complex lithium ion dynamics in simulated LiPO3 glass studied by means of multi-time correlation functions
Molecular dynamics simulations are performed to study the lithium jumps in
LiPO3 glass. In particular, we calculate higher-order correlation functions
that probe the positions of single lithium ions at several times. Three-time
correlation functions show that the non-exponential relaxation of the lithium
ions results from both correlated back-and-forth jumps and the existence of
dynamical heterogeneities, i.e., the presence of a broad distribution of jump
rates. A quantitative analysis yields that the contribution of the dynamical
heterogeneities to the non-exponential depopulation of the lithium sites
increases upon cooling. Further, correlated back-and-forth jumps between
neighboring sites are observed for the fast ions of the distribution, but not
for the slow ions and, hence, the back-jump probability depends on the
dynamical state. Four-time correlation functions indicate that an exchange
between fast and slow ions takes place on the timescale of the jumps
themselves, i.e., the dynamical heterogeneities are short-lived. Hence, sites
featuring fast and slow lithium dynamics, respectively, are intimately mixed.
In addition, a backward correlation beyond the first neighbor shell for highly
mobile ions and the presence of long-range dynamical heterogeneities suggest
that fast ion migration occurs along preferential pathways in the glassy
matrix. In the melt, we find no evidence for correlated back-and-forth motions
and dynamical heterogeneities on the length scale of the next-neighbor
distance.Comment: 12 pages, 13 figure
Characterization of a Mixed Methanotrophic Culture Capable of Chloroethylene Degradation
A consortium of methanotrophs cultured from the St. Joseph's aquifer in Schoolcraft, MI, was found to exhibit similar methane consumption rates as pure cultures of methanotrophs. The methanotrophic consortium resides within a portion of the aquifer contaminated with a mixed waste plume of perchloroethylene (PCE) and its reductive dechlorination products from natural attenuation, trichloroethylene (TCE), cis-dichloroethylene (c-DCE), and vinyl chloride (VC). Oxidation kinetics for TCE, c-DCE, and VC were measured for the mixed methanotroph consortium and compared to reported rate parameters for degradation of these chloroethylene compounds by pure methanotrophic cultures. The results demonstrate that the kinetics of chloroethylene oxidation by the Schoolcraft methanotroph population mimic the degradation rates of pure methanotrophic cultures that primarily express particulate methane monooxygenase (pMMO). Molecular and biochemical analyses confirmed that sMMO was not being expressed by these cells. Rather, using competitive reverse transcriptionpolymerase chain reaction, pmoA, a gene encoding one of the polypeptides of the pMMO was found at a level of (1.57 ± 0.10) × 10–17 mol pmoA mRNA/g wet soil in soil slurries and (2.65 ± 0.43) × 10–17 mol pmoA mRNA/μl in groundwater. No expression of mmoX, a gene encoding one of the polypeptides of the sMMO, was detected.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63398/1/ees.2005.22.177.pd
Changes in inflammatory mediators in experimental periodontitis in the rhesus monkey.
Ligature-induced periodontitis was monitored for 6 months in eight Macaca mulatta monkeys to examine clinical status, radiographic bone level, and crevicular fluid (CF) levels of prostaglandin E2 (PGE2), thromboxane B2 (TxB2), interleukin-1 beta (IL-1 beta), tumor necrosis factor alpha, and leukotriene B4 (LTB4). A split-mouth design was used, with eight ligated teeth and eight contralateral nonligated teeth which develop soft-chow-promoted (spontaneous) disease. Ligated sites experienced an average attachment loss of 0.94 mm per site and linear bone loss of 0.88 mm per site, with spontaneous-periodontitis sites experiencing approximately half the loss of ligated sites. The CF mediator levels showed increased levels of PGE2 and TxB2 at the ligated sites, as compared with the spontaneous sites, with no significant contralateral differences in the IL-1 beta or LTB4 responses. The concentrations of LTB4 in CF reached an early threefold peak over the baseline level at 1 month. By 2 months there was a statistically significant threefold elevation in CF-PGE2 in the ligated sites and a twofold elevation in the spontaneous sites as compared to the baseline level (P = 0.041 and 0.008, respectively). The monocyte product IL-1 beta increased sharply at 2 months and returned to the baseline level by 6 months at both ligated and nonligated sites. Tumor necrosis factor alpha in CF was below the limit of detection at all sites throughout the experiment (i.e., < 2 ng/ml). The selective elevation of both PGE2 and TxB2 in ligated sites, compared with levels in spontaneous sites, in the presence of similar levels of LTB4 and IL-1 beta provides further evidence that these molecules regulate the magnitude of the tissue-destructive response in progressive periodontitis
Psychosocial, socio-cultural, and environmental influences on mental health help-seeking among African-American men
http://dx.doi.org/10.1016/j.jomh.2012.03.00
Risk Categorization Using New American College of Cardiology/American Heart Association Guidelines for Cholesterol Management and Its Relation to Alirocumab Treatment Following Acute Coronary Syndromes
BACKGROUND: The 2018 US cholesterol management guidelines recommend
additional lipid-lowering therapies for secondary prevention in patients with lowdensity lipoprotein cholesterol ≥70 mg/dL or non−high-density lipoprotein cholesterol
≥100 mg/dL despite maximum tolerated statin therapy. Such patients are considered
at very high risk (VHR) based on a history of >1 major atherosclerotic cardiovascular
disease (ASCVD) event or a single ASCVD event and multiple high-risk conditions.
We investigated the association of US guideline-defined risk categories with the
occurrence of ischemic events after acute coronary syndrome and reduction of
those events by alirocumab, a PCSK9 (proprotein convertase subtilisin/kexin type 9)
inhibitor.
METHODS: In the ODYSSEY OUTCOMES trial (Evaluation of Cardiovascular
Outcomes After an Acute Coronary Syndrome During Treatment With Alirocumab),
patients with recent acute coronary syndrome and residual dyslipidemia despite
optimal statin therapy were randomly assigned to alirocumab or placebo. The primary
trial outcome (major adverse cardiovascular events, ie, coronary heart disease death,
nonfatal myocardial infarction, is
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