Effect of heat treatment on stiffness and damping of SiC/Ti-15-3

The effect of heat treatment on material properties of SiC/Ti-15-3 was measured by vibration tests. Heat treatment changes the microstructure, which was found to stiffen the matrix and reduce its damping capacity. Test results indicate how these changes in the matrix affect the corresponding properties of the composite. Measurements show that heat treatment affects damping properties of the composite to a greater extent than stiffness properties. The extent of change in mechanical properties is shown to depend on heat treatment temperature and exposure time

Evaluation of thermal and mechanical loading effects on the structural behavior of a SiC/titanium composite

Composite specimens of titanium-15-3 matrix reinforced with continuous SCS-6 silicon carbide fibers were tested under a variety of thermal and mechanical loadings. A combined experimental/finite element approach was used to estimate the effective in-situ modulus of the matrix material and to evaluate changes in modulus due to the applied loads. Several fiber orientations were tested. Results indicate that the effect of the thermal loads on composite stiffness varies with fiber orientation. Applications of this method to test specimens damaged by uniaxial tension, thermal cycling, and isothermal fatigue loadings are used to illustrate that by monitoring overall structural behavior, changes in stiffness caused by thermomechanical loading can be detected

Development of a Research Project Tracking System

The Kentucky Transportation Center, in cooperation with the Kentucky Transportation Cabinet, has developed a Research Project Tracking System (RPTS). The RPTS is web-based and includes a database of active (and recently completed) research projects. The system allows authorized users to access and edit the project data, enter new projects into the system, and produce periodic progress reports. It produces a homepage (or dashboard) for each project, and it provides links to key project documents. It also has the capability to track the implementation of research results on a project-by-project basis

Anthrax lethal toxin induced lysosomal membrane permeabilization and cytosolic cathepsin release is Nlrp1b/Nalp1b-dependent.

NOD-like receptors (NLRs) are a group of cytoplasmic molecules that recognize microbial invasion or 'danger signals'. Activation of NLRs can induce rapid caspase-1 dependent cell death termed pyroptosis, or a caspase-1 independent cell death termed pyronecrosis. Bacillus anthracis lethal toxin (LT), is recognized by a subset of alleles of the NLR protein Nlrp1b, resulting in pyroptotic cell death of macrophages and dendritic cells. Here we show that LT induces lysosomal membrane permeabilization (LMP). The presentation of LMP requires expression of an LT-responsive allele of Nlrp1b, and is blocked by proteasome inhibitors and heat shock, both of which prevent LT-mediated pyroptosis. Further the lysosomal protease cathepsin B is released into the cell cytosol and cathepsin inhibitors block LT-mediated cell death. These data reveal a role for lysosomal membrane permeabilization in the cellular response to bacterial pathogens and demonstrate a shared requirement for cytosolic relocalization of cathepsins in pyroptosis and pyronecrosis

Prevention of cisplatin-induced hearing loss in children: Informing the design of future clinical trials.

Cisplatin is an essential chemotherapeutic agent in the treatment of many pediatric cancers. Unfortunately, cisplatin-induced hearing loss (CIHL) is a common, clinically significant side effect with life-long ramifications, particularly for young children. ACCL05C1 and ACCL0431 are two recently completed Childrens Oncology Group studies focused on the measurement and prevention of CIHL. The purpose of this paper was to gain insights from ACCL05C1 and ACCL0431, the first published cooperative group studies dedicated solely to CIHL, to inform the design of future pediatric otoprotection trials. Use of otoprotective agents is an attractive strategy for preventing CIHL, but their successful development must overcome a unique constellation of methodological challenges related to translating preclinical research into clinical trials that are feasible, evaluate practical interventions, and limit risk. Issues particularly important for children include use of appropriate methods for hearing assessment and CIHL severity grading, and use of trial designs that are well-informed by preclinical models and suitable for relatively small sample sizes. Increasing interest has made available new funding opportunities for expanding this urgently needed research

Resolution of Clinical Signs of Ventilator-Associated Pneumonia in Trauma Patients

Objectives: The ATS/IDSA Ventilator-Associated Pneumonia (VAP) guidelines suggest that clinical improvement of VAP should be apparent within 3–6 days. This study evaluated resolution of clinical signs of VAP in trauma patients after diagnosis. Methods: Critically injured adults admitted to the trauma intensive care unit (ICU) from June 1, 2006, to December 31, 2007, and subsequently given a diagnosis of VAP were retrospectively assessed. Clinical signs, including derangements of maximum temperature (Tmax), white blood cell (WBC) count, and PaO2/FiO2, were evaluated on days 1–16 after VAP diagnosis. Data are presented as mean ± SD unless otherwise stated. Clinical parameters after VAP were compared using repeated-measures ANOVA with the Tukey test for multiple comparisons. Results: A total of 82 patients were identified. Data for the 34 patients without concurrent infections are presented. Demographic data include: Age 46 ± 17 years; 71% men; 94% blunt trauma; median (IQR) Injury Severity Score 29.5 (24–38); duration of mechanical ventilation 33 ± 27 days; ICU length of stay (LOS) 39 ± 25 days; hospital LOS 53 ± 33 days. Clinical signs following VAP diagnosis: Tmax (°F): Day 1=101.8 ± 1.3, Day 3=101.1 ± 1.1, Day 6=101.1 ± 1.4, Day 16=100.1 ± 3. Compared to Day 1, there was a significant reduction in Tmax at days 10, 11, 12, 13, 14, and 16 (p\u3c0.05 for all). WBC count (cells per microliter): day 1 = 12.9 ± 5, day 3 = 13.7 ± 5, day 6 = 14.4 ± 5, and day 16 = 13.8 ± 6. There was no significant difference in WBC on days 1–16 (p=0.42). PaO2/FiO2: day 1 = 232 ± 108, day 3 = 200 ± 87, day 6 = 218 ± 104, day 16 = 246 ± 126. Differences in PaO2/FiO2 on days 1–16 did not reach statistical significance (p=0.06). Conclusion: Improvement of clinical parameters after a VAP diagnosis is delayed in trauma patients. Alternative methods for determining resolution should be investigated. Published in To be published in Critical Care Medicine’s December 2009 supplement