The Unlubricated Sliding Wear Behavior of a Wrought Cobalt-Chromium Alloy Against Monolithic Ceramic Counterfaces

The unlubricated sliding wear and friction behavior of a wrought cobalt-chromium alloy against sintered Al2O3, ZrO2-toughened Al2O3, MgO-partially-stabilized ZrO2, and hot-pressed Si3N4 ceramic counterfaces has been investigated. Both untreated (baseline) and surface-borided conditions of alloy 6B disks were investigated. The dominant wear and/or material degradation mechanism for surface-borided alloy 6B was a combination of abrasion and plastic deformation; in addition, adhesive transfer of the cobalt alloy to monolithic Al2O3 counterfaces was a significant wear mechanism for the as-solution-treated alloy 6B disk. For the partially stabilized ZrO2 counterface, the degradation mechanism involved thermal and/or mechanical fatigue processes, resulting in the formation of microcracks in the 6B disks transverse to the sliding direction. This microcracking has been ascribed to the low thermal conductivity of the partially stabilized ZrO2 and the activation of a martensitic, fcc-to-hcp transition with each passing of the ZrO2 ball. For borided alloy 6B against hot-pressed Si3N4, a transition from negligible to severe wear was noted with increasing sliding speeds.</jats:p

Colpodella spp.–like Parasite Infection in Woman, China

The phylum Apicomplexa comprises intracellular protozoa that include many human pathogens. Their nearest relatives are chromerids and colpodellids. We report a case of a Babesia spp.–like relapsing infection caused by a newly described microorganism related to the Apicomplexa. This case is highly suggestive of a previously undescribed type of colpodellid that infects vertebrates

Effects of tick control by acaricide self-treatment of white-tailed deer on host-seeking tick infection prevalence and entomologic risk for Ixodes scapularis-borne pathogens

We evaluated the effects of tick control by acaricide self-treatment of white-tailed deer on the infection prevalence and entomologic risk for three Ixodes scapularis-borne bacteria in host-seeking ticks. Ticks were collected from vegetation in areas treated with the 4-Poster device and from control areas over a 6-year period in five geographically diverse study locations in the Northeastern United States and tested for infection with two known agents of human disease, Borrelia burgdorferi and Anaplasma phagocytophilum, and for a novel relapsing fever-group spirochete related to Borrelia miyamotoi. Overall, 38.2% of adults and 12.5% of nymphs were infected with B. burgdorferi; 8.5% of adults and 4.2% of nymphs were infected with A. phagocytophilum; and 1.9% of adults and 0.8% of nymphs were infected with B. miyamotoi. In most cases, treatment with the 4-Poster device was not associated with changes in the prevalence of infection with any of these three microorganisms among nymphal or adult ticks. However, the density of nymphs infected with B. burgdorferi, and consequently the entomologic risk for Lyme disease, was reduced overall by 68% in treated areas compared to control areas among the five study sites at the end of the study. The frequency of bacterial coinfections in ticks was generally equal to the product of the proportion of ticks infected with a single bacterium, indicating that enzootic maintenance of these pathogens is independent. We conclude that controlling ticks on deer by self-application of acaricide results in an overall decrease in the human risk for exposure to these three bacterial agents, which is due solely to a reduction in tick density. © Copyright 2009, Mary Ann Liebert, Inc

ITMS CAPABILITIES IN ISOMER ANALYSIS .3. CHARACTERIZATION OF METHYL AND DIMETHYL DERIVATIVES OF 8-DESMETHYLSESELINE, POTENTIAL ANTIPROLIFERATIVE AGENTS, BY TANDEM MASS-SPECTROMETRY

Two sets of isomeric pyranocoumarins and pyranochromones have been studied by both electron impact and collision-induced dissociation. The daughter spectra were obtained by ion trap mass spectrometry experiments. Characteristic fragments were obtained in electron impact that allowed differentiation between the chromone and the coumarin systems. Distinction between isomers in each set was achieved by collision-induced daughter spectra of selected parent ions

Definitions of parameters appearing in the <i>R</i>₀ model and point parameter values for the Connecticut and Block Island populations.

<p>A full description of parameters and corresponding references and field data can be found in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0115494#pone.0115494-Dunn1" target="_blank">[38]</a>. Burden parameters assume January 1^st as day 0.</p><p>Definitions of parameters appearing in the <i>R</i>₀ model and point parameter values for the Connecticut and Block Island populations.</p

Quantitative PCR for detection of Babesia microti in Ixodes scapularis ticks and in human blood

Babesia microti, the primary cause of human babesiosis in the United States, is transmitted by Ixodes scapularis ticks; transmission may also occur through blood transfusion and transplacentally. Most infected people experience a viral-like illness that resolves without complication, but those who are immunocompromised may develop a serious and prolonged illness that is sometimes fatal. The geographic expansion and increasing incidence of human babesiosis in the northeastern and midwestern United States highlight the need for high-throughput sensitive and specific assays to detect parasites in both ticks and humans with the goals of improving epidemiological surveillance, diagnosis of acute infections, and screening of the blood supply. Accordingly, we developed a B. microti-specific quantitative PCR (qPCR) assay (named BabMq18) designed to detect B. microti DNA in tick and human blood samples using a primer and probe combination that targets the 18S rRNA gene of B. microti. This qPCR assay was compared with two nonquantitative B. microti PCR assays by testing tick samples and was found to exhibit higher sensitivity for detection of B. microti DNA. The BabMq18 assay has a detection threshold of 10 copies per reaction and does not amplify DNA in I. scapularis ticks infected with Babesia odocoilei, Borrelia burgdorferi, Borrelia miyamotoi, or Anaplasma phagocytophilum. This highly sensitive and specific qPCR assay can be used for detection of B. microti DNA in both tick and human samples. Finally, we report the prevalence of B. microti infection in field-collected I. scapularis nymphs from three locations in southern New England that present disparate incidences of human babesiosis.Lindsay Rollend, Stephen J. Bent, Peter J. Krause, Sahar Usmani-Brown, Tanner K. Steeves, Sarah L. States, Timothy Lepore, Raymond Ryan, Fil Dias, Choukri Ben Mamoun, Durland Fish, and Maria A. Diuk-Wasse

The transmission graph for <i>Babesia microti</i> for singly infected and coinfected mice.

<p>Three ‘host types’ are defined: (1) <i>Peromyscus leucopus</i> mouse, <i>Borrelia burgdorferi</i> free, infected with <i>B. microti</i>, (2) <i>P. leucopus</i> mouse infected with <i>B. burgdorferi</i> and <i>B. microti</i> and (3) tick infected with <i>B. microti</i> during first blood meal. The transmission graph is used in the construction of the next-generation matrix (<i>K</i>) for <i>R</i>₀ where <i>k_ij</i> indicates the expected number of host type <i>i</i> infected by host type <i>j</i>.</p