Hemostasis by Compression and Heat

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Design of a controllable pitch underwater thruster system

Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution August 1993Control systems for underwater vehicles have reached the level of sophistication where they are limited by the dynamic performance of the thrust actuators. Standard fixed-pitch propellers have been shown to have very poor dynamic characteristics, particularly at low thrust levels The dynamic response of a fixed-pitch propeller is dependent upon highly non-linear transients encountered while the shaft speed approaches its steady-state value. This thesis proposes the use of a controllable pitch propeller system to address this problem. A controllable pitch propeller varies the amount of thrust produced by varying the pitch angle of the blades at a constant shaft speed. The bandwidth of this type of thrust actuator would be dependent primarily on the speed at which the pitch angle of the blades are changed. A variable pitch propeller system suitable for retrofit into an ROV is designed and built. The system is designed for maximal pitch angle bandwidth with low actuator power consumption

Clinical trials of potential cognitive-enhancing drugs in schizophrenia: what have we learned so far?

In light of the number of studies conducted to examine the treatment of cognitive impairment associated with schizophrenia (CIAS), we critically reviewed recent CIAS trials. Trials were identified through searches of the website "www.clinicaltrials.gov" using the terms "schizophrenia AND cognition," "schizophrenia AND neurocognition," "schizophrenia AND neurocognitive tests," "schizophrenia AND MATRICS," "schizophrenia AND MCCB," "schizophrenia AND BACS," "schizophrenia AND COGSTATE," and "schizophrenia AND CANTAB" and "first-episode schizophrenia AND cognition." The cutoff date was 20 April 2011. Included trials were conducted in people with schizophrenia, the effects on cognition were either a primary or secondary outcome, and the effect of a pharmacologically active substance was examined. Drug challenge, pharmacokinetic, pharmacodynamic, or prodrome of psychosis studies were excluded. We identified 118 trials, with 62% using an add-on parallel group design. The large majority of completed trials were underpowered to detect moderate effect sizes, had ≤8 weeks duration, and were performed in samples of participants with chronic stable schizophrenia. The ongoing add-on trials are longer, have larger sample sizes (with a number of them being adequately powered to detect moderate effect sizes), and are more likely to use a widely accepted standardized cognitive battery (eg, the MATRICS Consensus Cognitive Battery) and MATRICS guidelines. Ongoing studies performed in subjects with recent onset schizophrenia may help elucidate which subjects are most likely to show an effect in cognition. New insights into the demands of CIAS trial design and methodology may help increase the probability of identifying treatments with beneficial effect on cognitive impairment in schizophrenia

Streptavidin-binding peptides and uses thereof

The invention provides peptides with high affinity for streptavidin. These peptides may be expressed as part of fusion proteins to facilitate the detection, quantitation, and purification of proteins of interest

Limitations of variable number of tandem repeat typing identified through whole genome sequencing of Mycobacterium avium subsp. paratuberculosis on a national and herd level

Background: Mycobacterium avium subsp. paratuberculosis (MAP), the causative bacterium of Johne’s disease in dairy cattle, is widespread in the Canadian dairy industry and has significant economic and animal welfare implications. An understanding of the population dynamics of MAP can be used to identify introduction events, improve control efforts and target transmission pathways, although this requires an adequate understanding of MAP diversity and distribution between herds and across the country. Whole genome sequencing (WGS) offers a detailed assessment of the SNP-level diversity and genetic relationship of isolates, whereas several molecular typing techniques used to investigate the molecular epidemiology of MAP, such as variable number of tandem repeat (VNTR) typing, target relatively unstable repetitive elements in the genome that may be too unpredictable to draw accurate conclusions. The objective of this study was to evaluate the diversity of bovine MAP isolates in Canadian dairy herds using WGS and then determine if VNTR typing can distinguish truly related and unrelated isolates.<p></p> Results: Phylogenetic analysis based on 3,039 SNPs identified through WGS of 124 MAP isolates identified eight genetically distinct subtypes in dairy herds from seven Canadian provinces, with the dominant type including over 80% of MAP isolates. VNTR typing of 527 MAP isolates identified 12 types, including “bison type” isolates, from seven different herds. At a national level, MAP isolates differed from each other by 1–2 to 239–240 SNPs, regardless of whether they belonged to the same or different VNTR types. A herd-level analysis of MAP isolates demonstrated that VNTR typing may both over-estimate and under-estimate the relatedness of MAP isolates found within a single herd.<p></p> Conclusions: The presence of multiple MAP subtypes in Canada suggests multiple introductions into the country including what has now become one dominant type, an important finding for Johne’s disease control. VNTR typing often failed to identify closely and distantly related isolates, limiting the applicability of using this typing scheme to study the molecular epidemiology of MAP at a national and herd-level.<p></p&gt

The Role of Cognition and Social Functioning as Predictors in the Transition to Psychosis for Youth With Attenuated Psychotic Symptoms

In the literature, there have been several attempts to develop prediction models for youth who are at clinical high risk (CHR) of developing psychosis. Although there are no specific clinical or demographic variables that seem to consistently predict the later transition to psychosis in those CHR youth, in addition to attenuated psychotic symptoms, the most commonly occuring predictors tend to be poor social functioning and certain cognitive tasks. Unfortunately, there has been little attempt to replicate alogorithms. A recently published article by Cornblatt et al suggested that, for individuals with attentuated psychotic symptoms (APS), disorganized communication, suspiciousness, verbal memory, and a decline in social functioning were the best predictors of later transition to psychosis (the RAP model). The purpose of this article was to first test the prediction model of Cornblatt et al with a new sample of individuals with APS from the PREDICT study. The RAP model was not the best fit for the PREDICT data. However, using other variables from PREDICT, it was demonstrated that unusual thought content, disorganized communication, baseline social functioning, verbal fluency, and memory, processing speed and age were predictors of later transition to psychosis in the PREDICT sample. Although the predictors were different in these 2 models, both supported that disorganized communication, poor social functioning, and verbal memory, were good candidates as predictors for later conversion to psychosis