Microstructure of NiTi orthodontic wires observations using transmission electron microscopy

This work presents the results of the microstructure observation of six different types of NiTi orthodontic wires by using Transmission Electron Microscopy (TEM). Within these analyses the chemical compositions of each wire were observed in different places by applying the EDS detector. Namely, the chemical composition in the orthodontic wires is very important because it shows the dependence between the phase temperatures and mechanical properties. Microstructure observations showed that orthodontic wires consist of nano-sized grains containing precipitates of Ti₂Ni and/or TiC. The first precipitated Ti₂Ni are rich in Ti, while the precipitated TiC is rich in C. Further investigation showed that there was a difference in average grain size in the NiTi matrix. The sizes of grains in orthodontic wires are in the range from approximately 50 to 160 nm and the sizes of precipitate are in the range from 0,3 μm to 5 μm

Acute mucosal pathogenesis of feline immunodeficiency virus is independent of viral dose in vaginally infected cats

<p>Abstract</p> <p>Background</p> <p>The mucosal pathogenesis of HIV has been shown to be an important feature of infection and disease progression. HIV-1 infection causes depletion of intestinal lamina propria CD4+ T cells (LPL), therefore, intestinal CD4+ T cell preservation may be a useful correlate of protection in evaluating vaccine candidates. Vaccine studies employing the cat/FIV and macaque/SIV models frequently use high doses of parenterally administered challenge virus to ensure high plasma viremia in control animals. However, it is unclear if loss of mucosal T cells would occur regardless of initial viral inoculum dose. The objective of this study was to determine the acute effect of viral dose on mucosal leukocytes and associated innate and adaptive immune responses.</p> <p>Results</p> <p>Cats were vaginally inoculated with a high, middle or low dose of cell-associated and cell-free FIV. PBMC, serum and plasma were assessed every two weeks with tissues assessed eight weeks following infection. We found that irrespective of mucosally administered viral dose, FIV infection was induced in all cats. However, viremia was present in only half of the cats, and viral dose was unrelated to the development of viremia. Importantly, regardless of viral dose, all cats experienced significant losses of intestinal CD4+ LPL and CD8+ intraepithelial lymphocytes (IEL). Innate immune responses by CD56+CD3- NK cells correlated with aviremia and apparent occult infection but did not protect mucosal T cells. CD4+ and CD8+ T cells in viremic cats were more likely to produce cytokines in response to Gag stimulation, whereas aviremic cats T cells tended to produce cytokines in response to Env stimulation. However, while cell-mediated immune responses in aviremic cats may have helped reduce viral replication, they could not be correlated to the levels of viremia. Robust production of anti-FIV antibodies was positively correlated with the magnitude of viremia.</p> <p>Conclusions</p> <p>Our results indicate that mucosal immune pathogenesis could be used as a rapid indicator of vaccine success or failure when combined with a physiologically relevant low dose mucosal challenge. We also show that innate immune responses may play an important role in controlling viral replication following acute mucosal infection, which has not been previously identified.</p

Identification and structural analysis of the tripartite α-pore forming toxin of Aeromonas hydrophila

The alpha helical CytolysinA family of pore forming toxins (α-PFT) contains single, two, and three component members. Structures of the single component Eschericia coli ClyA and the two component Yersinia enterolytica YaxAB show both undergo conformational changes from soluble to pore forms, and oligomerization to produce the active pore. Here we identify tripartite α-PFTs in pathogenic Gram negative bacteria, including Aeromonas hydrophila (AhlABC). We show that the AhlABC toxin requires all three components for maximal cell lysis. We present structures of pore components which describe a bi-fold hinge mechanism for soluble to pore transition in AhlB and a contrasting tetrameric assembly employed by soluble AhlC to hide their hydrophobic membrane associated residues. We propose a model of pore assembly where the AhlC tetramer dissociates, binds a single membrane leaflet, recruits AhlB promoting soluble to pore transition, prior to AhlA binding to form the active hydrophilic lined pore

Estimating Statistics of Milk Consumption in Relation to Trends in Fluid Milk Marketing

Excerpt from the Introduction: Many decisions in dairy marketing depend on information about rates of milk consumption, and the U. S. Department of Agriculture has been providing such information for nearly 40 years. During that time, the kinds of information that it has been practicable to gather and the demands of the users have both changed. This report is intended to familiarize users with the information on milk consumption currently being published by the Department

Agriculture in Vietnam's Economy: A System for Economic Analysis

This USDA/AID work pulls a broad range of Vietnam economic and demographic data into an economic intelligence system. The analyses of these data lend valuable insights into inner workings of the Vietnamese economy to aid decisionmakers. Data inadequacies are apparent, but the USDA/AID team worked to develop as much economic information as possible into a logical system rather than dwelling on data shortcomings. Several analytical techniques are used to quantify economic relationships. Regression analysis, ranging from simple linear relationships to polynomial distributed lags, formed the basis of most of the analysis. Supply and utilization tables were constructed for major commodities, supplemented by seasonal analyses, index number construction, and a detailed economic profile. Much of the analysis is then drawn into an illustrative multi-equation framework of the Vietnamese economy. This framework provides important guides to policymakers through simulated alternative assumption levels. It also demonstrates important interrelationships within the agricultural sector, as well as between agriculture and the national accounts. Important conclusions are: ---Formal analytic techniques can give reasonable results even with data inadequacies and social upheaval. These techniques demonstrate that relative food prices are directly related to differences in income and demand elasticities. ---Assuming stable relative food prices: (1) More than a third increase in food production will be required over the next 5 years to feed the growing population and offset food imports. (2) Additional food production increases may be absorbed by increased domestic demand resulting from increased GNP and associated higher income levels

Pathogenetic Implications of the Age at Time of Diagnosis and Skin Location for Acrodermatitis Chronica Atrophicans

BACKGROUND: The pathogenesis of acrodermatitis chronica atrophicans (ACA) is not well understood. OBJECTIVE: The purpose of this study was to gain a better understanding of ACA by utilizing a large data set of adult Slovenian patients with Lyme borreliosis. METHODS: The age of 590 ACA patients was compared with that of patients with other manifestations of Lyme borreliosis. The location of the ACA lesion on the body was compared with that of erythema migrans (EM). RESULTS: Patients diagnosed with ACA were on average 14.3 years older than patients with EM (p\u3c0.001). ACA patients were also significantly older than patients with Lyme neuroborreliosis or Lyme arthritis (p\u3c0.001). The average delay in diagnosis of ACA was 1.6 years (range 0.1-20 years). For 572 (96.9%) of the ACA patients, the site of the skin lesion(s) was confined to an extremity vs. 79.6% for patients with EM, p\u3c0.001. For the 20 ACA patients who reported a preceding untreated EM lesion at the same body site, the mean time between the development of the EM and the onset of ACA was 3.0+/-4.4 (median 1.3, range 0.1-15.0) years. CONCLUSIONS: ACA is more likely to be diagnosed in older individuals than any other manifestation of Lyme borreliosis. ACA is more likely than EM to be localized anatomically to the extremities. Available data favor the hypothesis that ACA occurs most often on the extremities of older individuals because of predisposing age-related anatomic or physiologic changes, but more data are needed to define the latency period and other aspects of the pathogenesis of this skin condition