104 research outputs found

    Repositioning Manhattan office buildings

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    Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 1989.Includes bibliographical references (leaves 129-131).by Lesley D. Cummin and Andrew H. Popik.M.S

    A latent class analysis of Parkinson's disease symptoms

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    Parkinson’s disease is a neurological disease in which the dopamine releasing brain cells degenerate die and are not replaced. Affecting mostly persons older than age 60, in the US population the fraction above 60 is nearly 40 percent. This population is also growing more elderly. The public health importance of correctly assessing Parkinson’s disease and the accompanying symptom burden in order to effectively and efficiently treat the growing elderly population in the US and in order to keep costs and expectation managed is high. The ability to identify clusters of symptoms could improve awareness of how to treat and counsel patients. Latent Class Analysis is a method which can be used to predict classes, or clusters, and which can be used with categorical outcomes. In this thesis, the Parkinson’s symptoms were clustered into four classes characterized in part by sex and age of the patient. Unique symptoms predicted at greater than 50% were identified for three of these classes, the first and reference class reported very few symptoms. Relative to the first class, the second class was more likely to have a younger age at onset, but was not more likely to be male or female, and uniquely reported Mood swings and depression (76%). The third class was more likely to be male, but was not more likely to be older or younger at age of onset, and uniquely reported difficulty standing from a chair (73%). The fourth class was more likely to be female and to be younger at age of onset relative to class 1, and uniquely reported 4 unique symptoms, sweating (62%), muscle spasm (70%), hot flashes or chills (57%) and persistent dull pain (59%).This LCA model predicts divisions across gender and sex in the specific symptoms and their associations in keeping with clinical expectations

    Miniature High-Force, Long-Stroke SMA Linear Actuators

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    Improved long-stroke shape-memory-alloy (SMA) linear actuators are being developed to exert significantly higher forces and operate at higher activation temperatures than do prior SMA actuators. In these actuators, long linear strokes are achieved through the principle of displacement multiplication, according to which there are multiple stages, each intermediate stage being connected by straight SMA wire segments to the next stage so that relative motions of stages are additive toward the final stage, which is the output stage. Prior SMA actuators typically include polymer housings or shells, steel or aluminum stages, and polymer pads between successive stages of displacement-multiplication assemblies. Typical output forces of prior SMA actuators range from 10 to 20 N, and typical strokes range from 0.5 to 1.5 cm. An important disadvantage of prior SMA wire actuators is relatively low cycle speed, which is related to actuation temperature as follows: The SMA wires in prior SMA actuators are typically made of a durable nickel/titanium alloy that has a shape-memory activation temperature of 80 C. An SMA wire can be heated quickly from below to above its activation temperature to obtain a stroke in one direction, but must then be allowed to cool to somewhat below its activation temperature (typically, less than or equal to 60 C in the case of an activation temperature of 80 C) to obtain a stroke in the opposite direction (return stroke). At typical ambient temperatures, cooling times are of the order of several seconds. Cooling times thus limit cycle speeds. Wires made of SMA alloys having significantly higher activation temperatures [denoted ultra-high-temperature (UHT) SMA alloys] cool to the required lower return-stroke temperatures more rapidly, making it possible to increase cycle speeds. The present development is motivated by a need, in some applications (especially aeronautical and space-flight applications) for SMA actuators that exert higher forces, operate at greater cycle speeds, and have stronger housings that can withstand greater externally applied forces and impacts. The main novel features of the improved SMA actuators are the following: 1) The ends of the wires are anchored in compact crimps made from short steel tubes. Each wire end is inserted in a tube, the tube is flattened between planar jaws to make the tube grip the wire, the tube is compressed to a slight U-cross-section deformation to strengthen the grip, then the crimp is welded onto one of the actuator stages. The pull strength of a typical crimp is about 125 N -- comparable to the strength of the SMA wire and greater than the typical pull strengths of wire-end anchors in prior SMA actuators. Greater pull strength is one of the keys to achievement of higher actuation force; 2) For greater strength and resistance to impacts, housings are milled from aluminum instead of being made from polymers. Each housing is made from two pieces in a clamshell configuration. The pieces are anodized to reduce sliding friction; 3) Stages are made stronger (to bear greater compression loads without excessive flexing) by making them from steel sheets thicker than those used in prior SMA actuators. The stages contain recessed pockets to accommodate the crimps. Recessing the pockets helps to keep overall dimensions as small as possible; and, 4) UHT SMA wires are used to satisfy the higher-speed/higher-temperature requirement

    Mutation screening using formalin-fixed paraffin-embedded tissues: a stratified approach according to DNA quality.

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    DNA samples from formalin-fixed paraffin-embedded tissues are highly degraded with variable quality, and this imposes a big challenge for targeted sequencing due to false positives, largely caused by PCR errors and cytosine deamination. To eliminate false positives, a common practice is to validate the detected variants by Sanger sequencing or perform targeted sequencing in duplicate. Technically, PCR errors could be removed by molecular barcoding of template DNA prior to amplification as in the HaloPlexHS design. Nonetheless, it is uncertain to what extent variants detected using this approach should be further validated. Here, we addressed this question by correlating variant reproducibility with DNA quality using HaloPlexHS target enrichment and Illumina HiSeq4000, together with an in-house validated variant calling algorithm. The overall sequencing coverage, as shown by analyses of 70 genes in 266 cases of large B-cell lymphoma, was excellent (98%) in DNA samples amenable for PCR of ≥400 bp, but suboptimal (92%) and poor (80%) in those amenable for PCR of 300 bp and 200 bp respectively. By mutation analysis in duplicate in 93 cases, we demonstrated that 20 alternative allele depth (AAD) was an optimal cut-off value for separating reproducible from non-reproducible variants in DNA samples amenable for PCR of ≥300 bp, with 97% sensitivity and 100% specificity. By cross validation with a previously established targeted sequencing protocol by Fluidigm-PCR and Illumina MiSeq, the HaloPlexHS protocol was shown to be highly sensitive and specific in mutation screening. To conclude, we proposed a stratified approach for mutation screening by HaloplexHS and Illumina HiSeq4000 according to DNA quality. DNA samples with good quality (≥400 bp) are amenable for mutation analysis with a single replicate, with only variants at 15-20 AAD requiring for further validation, while those with suboptimal quality (300 bp) are better analysed in duplicate with reproducible variants at >15 AAD regarded as true genetic changes

    Induction therapy with the MATRix regimen in patients with newly diagnosed primary diffuse large B-cell lymphoma of the central nervous system - an international study of feasibility and efficacy in routine clinical practice

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    The MATRix chemoimmunotherapy regimen is highly effective in patients with newly diagnosed primary diffuse large B-cell lymphoma of the central nervous system (PCNSL). However, nothing is known about its feasibility and efficacy in everyday practice, where patients are more often older/frailer than those enrolled in clinical trials. We conducted a retrospective study addressing tolerability/efficacy of MATRix in 156 consecutive patients with newly diagnosed PCNSL treated outside a clinical trial. Median age and ECOG Performance Status of considered patients were 62 years (range 28–78) and 2 (range 0–4). The overall response rate after MATRix was 79%. Nine (6%) treatment-related deaths were recorded. After a median follow-up of 27.4 months (95% confidence interval [CI] 24.4–31.9%), the two-year progression-free and overall survival were 56% (95% CI 48.4–64.9%) and 64.1% (95% CI 56.7–72.5%) respectively. Patients not eligible for the IELSG32 trial were treated with lower dose intensity and had substantially worse outcomes than those fulfilling inclusion criteria. This is the largest series of PCNSL patients treated with MATRix outside a trial and recapitulates the IELSG32 trial outcomes in the non-trial setting for patients who fit the trial criteria. These data underscore the feasibility and efficacy of MATRix as induction treatment for fit patients in routine practice

    In Vitro Anti-Listerial Activities of Crude n-Hexane and Aqueous Extracts of Garcinia kola (heckel) Seeds

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    We assessed the anti-Listerial activities of crude n-hexane and aqueous extracts of Garcinia kola seeds against a panel of 42 Listeria isolates previously isolated from wastewater effluents in the Eastern Cape Province of South Africa and belonging to Listeria monocytogenes, Listeria grayi and Listeria ivanovii species. The n-hexane fraction was active against 45% of the test bacteria with zones of inhibition ranging between 8–17 mm, while the aqueous fraction was active against 29% with zones of inhibition ranging between 8–11 mm. The minimum inhibitory concentrations (MIC) were within the ranges of 0.079–0.625 mg/mL for the n-hexane extract and 10 to >10 mg/mL for the aqueous extract. The rate of kill experiment carried out for the n-hexane extract only, revealed complete elimination of the initial bacterial population for L. grayi (LAL 15) at 3× and 4× MIC after 90 and 60 min; L. monocytogenes (LAL 8) at 3× and 4× MIC after 60 and 15 min; L. ivanovii (LEL 18) at 3× and 4× MIC after 120 and 15 min; L. ivanovii (LEL 30) at 2, 3 and 4× MIC values after 105, 90 and 15 min exposure time respectively. The rate of kill activities were time- and concentration-dependant and the extract proved to be bactericidal as it achieved a more than 3log10 decrease in viable cell counts after 2 h exposure time for all of the four test organisms at 3× and 4× MIC values. The results therefore show the potential presence of anti-Listerial compounds in Garcinia kola seeds that can be exploited in effective anti-Listerial chemotherapy

    Functional and Transcriptional Induction of Aquaporin-1 Gene by Hypoxia; Analysis of Promoter and Role of Hif-1α

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    Aquaporin-1 (AQP1) is a water channel that is highly expressed in tissues with rapid O2 transport. It has been reported that this protein contributes to gas permeation (CO2, NO and O2) through the plasma membrane. We show that hypoxia increases Aqp1 mRNA and protein levels in tissues, namely mouse brain and lung, and in cultured cells, the 9L glioma cell line. Stopped-flow light-scattering experiments confirmed an increase in the water permeability of 9L cells exposed to hypoxia, supporting the view that hypoxic Aqp1 up-regulation has a functional role. To investigate the molecular mechanisms underlying this regulatory process, transcriptional regulation was studied by transient transfections of mouse endothelial cells with a 1297 bp 5′ proximal Aqp1 promoter-luciferase construct. Incubation in hypoxia produced a dose- and time-dependent induction of luciferase activity that was also obtained after treatments with hypoxia mimetics (DMOG and CoCl2) and by overexpressing stabilized mutated forms of HIF-1α. Single mutations or full deletions of the three putative HIF binding domains present in the Aqp1 promoter partially reduced its responsiveness to hypoxia, and transfection with Hif-1α siRNA decreased the in vitro hypoxia induction of Aqp1 mRNA and protein levels. Our results indicate that HIF-1α participates in the hypoxic induction of AQP1. However, we also demonstrate that the activation of Aqp1 promoter by hypoxia is complex and multifactorial and suggest that besides HIF-1α other transcription factors might contribute to this regulatory process. These data provide a conceptual framework to support future research on the involvement of AQP1 in a range of pathophysiological conditions, including edema, tumor growth, and respiratory diseases
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