341 research outputs found

    Characteristics of versatile buildings

    Get PDF
    Thesis (M. Arch)--Massachusetts Institute of Technology, Dept. of Architecture, 1983.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCHText on even numbered pages runs from back to front.Includes bibliographical references (p. 81).If a building is to maintain its life-long usefulness it must be possible to alter it to accommodate different programmatic demands. This thesis investigates the spatial and material character that facilitates this architectural accommodation of diversity and change: Framed New England houses are compared with contemporary office buildings for their adaptability. A program of office and residential space is presented for a small valley near Brownsville Vermont. A building type is planned for this context and inhabited several ways to test its capabilities.by Stephen N. Mahler.M.Arc

    Production and characterization of specific monoclonal antibodies binding the Plasmodium falciparum diagnostic biomarker, histidine-rich protein 2

    Get PDF
    BACKGROUND: Early and accurate diagnosis of Plasmodium falciparum infection is important for providing appropriate treatment to patients with malaria. However, technical limitations of currently available diagnostic tests limit their use in control programs. One possible explanation for the vulnerability of current antibodies used in RDTs is their propensity to degrade at high ambient temperatures. Isolation of new antibodies with better thermal stability represents an appealing approach to improve the performance of RDTs. METHODS: In this study, phage display technology was deployed to isolate novel binders by screening a human naïve scFv antibody library against recombinant Plasmodium falciparum histidine rich protein 2 (rPfHRP2). The isolated scFv clones were reformatted to whole IgG and the recombinant mAbs were produced in a mammalian CHO cell expression system. To verify the biological activity of these purified recombinant mAbs, range of functional assays were characterized. RESULTS: Two unique clones (D2 and F9) were isolated after five rounds of biopanning. The reformatted and expressed antibodies demonstrated high binding specificity to malaria recombinant PfHRP2 and native proteins. When 5 μg/mL of mAbs applied, mAb C1-13 had the highest sensitivity, with an OD value of 1, the detection achieved 5 ng/mL of rPfHRP2, followed by mAbs D2 and F9 at 10 ng/mL and 100 ng/mL of rPfHRP2, respectively. Although the sensitivity of mAbs D2 and F9 was lower than the control, these recombinant human mAbs have shown better stability compared to mouse mAb C1-13 at various temperatures in DSC and blot assays. In view of epitope mapping, the predominant motif of rPfHRP2 recognized by mAb D2 was AHHAADAHHA, whereas mAb F9 was one amino acid shorter, resulting in AHHAADAHH. mAb F9 had the strongest binding affinity to rPfHRP2 protein, with a K(D) value of 4.27 × 10(−11) M, followed by control mAb C1-13 at 1.03 × 10(−10) M and mAb D2 at 3.05 × 10(−10) M. CONCLUSIONS: Overall, the performance of these mAbs showed comparability to currently available PfHRP2-specific mouse mAb C1-13. The stability of these novel binders indicate that they merit further work to evaluate their utility in the development of new generation point of care diagnosis of malaria

    Exploring metabolic demands of high density CHO-cell cultures

    Get PDF
    As the world population continues to grow and age, access to medical therapies, like therapeutic monoclonal antibodies (mAb), increases in importance. Chinese hamster ovary (CHO) cells are the preferred expression platform for biopharmaceutical production, such as mAb, due to their ability to generate human-like post-translational modifications and strong legislation background. Unfortunately, biopharmaceuticals production using CHO cells is costly leading to an expensive product. Detailed knowledge of their metabolic demands is still lacking. Hence, increasing understanding would help to develop rational approaches to enhance expression, lower production costs and subsequently make therapies more accessible. Industrial large scale CHO cell cultures are typically run in fed-batch mode, which is limited by the accumulation of inhibitory by-products. Driven by higher volumetric productivities, shorter residence time of products, industry is shifting towards perfusion cultures. This shift in cultivation mode is accompanied by new metabolic conditions for the cell in form of higher cell densities and different exometabolite levels. Comparison of both culturing modes, as well as different perfusion dilution rates, revealed differences in growth and productivity patterns. Cell densities and cell specific productivities increased from fed-batch to perfusion and from low to high dilution rates. Aiming to progress from pattern observations to a systems biology view, the metabolome and proteome profiles of both cultures modes will be analysed and mapped onto the CHO genome-scale model. Thus, protein expression and metabolite levels will be compared on a genome wide level and provide a metabolic profile, specific for the culture condition. Alterations between metabolic profiles of different culture conditions can then be identified, understood and utilized to reverse engineer variations by using genetic engineering approaches or media design and process optimization. Overall, this study aims to establish a systems biology approach to better understand the CHO cell metabolism in the aspect of emerging perfusion systems based on comparison of different culture modes

    Dopamine terminals from the ventral tegmental area gate intrinsic inhibition in the prefrontal cortex.

    Get PDF
    Spike frequency adaptation (SFA or accommodation) and calcium-activated potassium channels that underlie after-hyperpolarization potentials (AHP) regulate repetitive firing of neurons. Precisely how neuromodulators such as dopamine from the ventral tegmental area (VTA) regulate SFA and AHP (together referred to as intrinsic inhibition) in the prefrontal cortex (PFC) remains unclear. Using whole cell electrophysiology, we measured intrinsic inhibition in prelimbic (PL) layer 5 pyramidal cells of male adult rats. Results demonstrate that bath application of dopamine reduced intrinsic inhibition (EC50: 25.0 μmol/L). This dopamine action was facilitated by coapplication of cocaine (1 μmol/L), a blocker of dopamine reuptake. To evaluate VTA dopamine terminals in PFC slices, we transfected VTA dopamine cells of TH::Cre rats in vivo with Cre-dependent AAVs to express channelrhodopsin-2 (ChR2) or designer receptors exclusively activated by designer drugs (DREADDS). In PFC slices from these animals, stimulation of VTA terminals with either blue light to activate ChR2 or bath application of clozapine-N-oxide (CNO) to activate Gq-DREADDs produced a similar reduction in intrinsic inhibition in PL neurons. Electrophysiological recordings from cells expressing retrograde fluorescent tracers showed that this plasticity occurs in PL neurons projecting to the accumbens core. Collectively, these data highlight an ability of VTA terminals to gate intrinsic inhibition in the PFC, and under appropriate circumstances, enhance PL neuronal firing. These cellular actions of dopamine may be important for dopamine-dependent behaviors involving cocaine and cue-reward associations within cortical-striatal circuits

    Prefrontal Pathways Provide Top-Down Control of Memory for Sequences of Events

    Get PDF
    We remember our lives as sequences of events, but it is unclear how these memories are controlled during retrieval. In rats, the medial prefrontal cortex (mPFC) is positioned to influence sequence memory through extensive top-down inputs to regions heavily interconnected with the hippocampus, notably the nucleus reuniens of the thalamus (RE) and perirhinal cortex (PER). Here, we used an hM4Di synaptic-silencing approach to test our hypothesis that specific mPFC→RE and mPFC→PER projections regulate sequence memory retrieval. First, we found non-overlapping populations of mPFC cells project to RE and PER. Second, suppressing mPFC activity impaired sequence memory. Third, inhibiting mPFC→RE and mPFC→PER pathways effectively abolished sequence memory. Finally, a sequential lag analysis showed that the mPFC→RE pathway contributes to a working memory retrieval strategy, whereas the mPFC→PER pathway supports a temporal context memory retrieval strategy. These findings demonstrate that mPFC→RE and mPFC→PER pathways serve as top-down mechanisms that control distinct sequence memory retrieval strategies

    Impact on Diet Quality and Resilience in Urban Community Dwelling Obese Women with a Nutrition and Physical Activity Intervention

    Get PDF
    Objective: To examine the effect of a Tai Chi, resistance training, and behaviorally-based diet education intervention on dietary quality as well as resilience and physical resilience in obese older women. Design: Community health outreach with a quasi-experimental design. Setting: An urban senior center in Rhode Island. Participants: Thirty-three women, 85% were minorities, with mean age of 65±8.2 years and BMI of 37.3±4.6 kg/m2, were enrolled in the study at baseline however only 17 women in the intervention (EXD) group and 9 women in the wait-list control (CON) group completed the study. Measurement: Dietary quality and nutrition risk were measured using the Dietary Screening Tool (DST), resilience was measured by the Resilience Scale, and physical resilience was examined using the Physical Resilience Scale. Intervention: Participants in the EXD group engaged in 12 weeks of Tai Chi, resistance training, and behaviorally-based diet education. The diet education was based off of the modified Dietary Approaches to Stop Hypertension (DASH) diet and led by a Registered Dietitian. Results: There was no change in dietary quality by group or time. However the EXD group had significantly higher dietary quality compared to the control group (p=0.025) at post intervention, although there was no difference in nutrition risk category. There was no change seen in overall resilience, however the EXD group improved physical resilience (p=0.048). Conclusion: A community health outreach that involved Tai Chi, resistance training, and behaviorally-based diet education may promote higher dietary quality as well as improve physical resilience in obese older women
    • …
    corecore