3,697 research outputs found

    DEVELOPMENT OF FUNCTIONAL NANOPARTICULATE MATERIALS: Examination of the Functional and Structural Properties of Nanoparticulate Metal Complexes Prepared by Precipitation with Compressed Antisolvent Technology

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    A diverse set of systems that interact with nitric oxide (NO) is important because of its adverse role in environmental chemistry and importance in mammalian biology. Towards this effort, nanomaterials that interact with NO have been developed because they can display beneficial and unique chemical and physical properties from their larger counterparts. While several nanomaterials have been developed that store and release NO, few systems composed entirely of metal complexes have been reported. The research described in this dissertation involves the development of nanomaterials that interact with NO. Molecule-based nanoparticulate metal complexes were prepared using precipitation with compressed antisolvent technology. Microscopy and powder x-ray diffraction were used to determine that the nanoparticles form lamellar structures during processing. These nanoparticulates also displayed enhanced reactivity towards NO and O2 compared to their unprocessed analogs. The preparative routes towards the synthesis of immobilized metal complexes within silica particles are also discussed

    A heparin-mimicking polymer conjugate stabilizes basic fibroblast growth factor.

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    Basic fibroblast growth factor (bFGF) is a protein that plays a crucial role in diverse cellular functions, from wound healing to bone regeneration. However, a major obstacle to the widespread application of bFGF is its inherent instability during storage and delivery. Here, we describe the stabilization of bFGF by covalent conjugation with a heparin-mimicking polymer, a copolymer consisting of styrene sulfonate units and methyl methacrylate units bearing poly(ethylene glycol) side chains. The bFGF conjugate of this polymer retained bioactivity after synthesis and was stable to a variety of environmentally and therapeutically relevant stressors--such as heat, mild and harsh acidic conditions, storage and proteolytic degradation--unlike native bFGF. Following the application of stress, the conjugate was also significantly more active than the control conjugate system in which the styrene sulfonate units were omitted from the polymer structure. This research has important implications for the clinical use of bFGF and for the stabilization of heparin-binding growth factors in general

    Comparisons of Medical Student Knowledge Regarding Life-Threatening CT Images Before and After Clinical Experience

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    Introduction. Currently, no national standard exists for educatingmedical students regarding radiography or formal research indicatingthe level of improvement regarding computed tomography(CT) interpretation of medical students during clinical rotations. Methods. Students were evaluated based on their response totwenty-two open-ended questions regarding diagnosis and treatmentof eleven de-identified CT images of life-threatening injuries.The number of incorrect answers was compared withcorrect or partially correct answers between students startingthird-year clinical rotations and those starting their fourth year. Results. Survey results were collected from 65 of 65 (100%) beginningthird-year students and 9 of 60 (15%) beginning fourthyearstudents. Students in their fourth-year had less incorrectanswers compared to third-year students, with five questionsreflecting a statistically significant reduction in incorrect responses.The image with the least incorrect for both groups wasepidural hemorrhage, 33.9% and 18.5% incorrect for third-yearstudents for diagnosis and treatment, respectively, and 11.1%and 0% incorrect for fourth-year students. Outside of this image,the range of incorrect answers for third-year students was75.4% to 100% and 44.4% to 100% for fourth-year students. Conclusion. Baseline CT knowledge of medical students,regardless of clinical experience, indicated a strong deficit,as more students were incorrect than correct for themajority of CT images. KS J Med 2017;10(3):55-58

    Utilization of Bayesian Optimization and KWN Modeling for Increased Efficiency of Alā€Sc Precipitation Strengthening

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    The Kampmann and Wagner numerical model was adapted in MATLAB to predict the precipitation and growth of Al3Sc precipitates as a function of starting concentration and heatā€treatment steps. This model was then expanded to predict the strengthening in alloys using calculated average precipitate number density, radius, etc. The calibration of this model was achieved with Bayesian optimization, and the model was verified against experimentally gathered hardness data. An analysis of the outputs from this code allowed the development of optimal heat treatments, which were validated experimentally and proven to result in higher final strengths than were previously observed. Bayesian optimization was also used to predict the optimal heatā€treatment temperatures in the case of limited heatā€treatment times

    802.16e System Profile for NASA Extra-Vehicular Activities

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    This report identifies an 802.16e system profile that is applicable to a lunar surface wireless network, and specifically for meeting extra-vehicular activity (EVA) data flow requirements. EVA suit communication needs are addressed. Design-driving operational scenarios are considered. These scenarios are then used to identify a configuration of the 802.16e system (system profile) that meets EVA requirements, but also aim to make the radio realizable within EVA constraints. Limitations of this system configuration are highlighted. An overview and development status is presented by Toyon Research Corporation concerning the development of an 802.16e compatible modem under NASA s Small Business Innovative Research (SBIR) Program. This modem is based on the recommended system profile developed as part of this report. Last, a path forward is outlined that presents an evolvable solution for the EVA radio system and lunar surface radio networks. This solution is based on a custom link layer, and 802.16e compliant physical layer compliant to the identified system profile, and a later progression to a fully interoperable 802.16e system

    CRLX101, a Nanoparticleā€“Drug Conjugate Containing Camptothecin, Improves Rectal Cancer Chemoradiotherapy by Inhibiting DNA Repair and HIF1Ī±

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    Novel agents are needed to improve chemoradiotherapy for locally advanced rectal cancer. In this study, we assessed the ability of CRLX101, an investigational nanoparticle-drug conjugate containing the payload camptothecin (CPT), to improve therapeutic responses as compared to standard chemotherapy. CRLX101 was evaluated as a radiosensitizer in colorectal cancer cell lines and murine xenograft models. CRLX101 was as potent as CPT in vitro in its ability to radiosensitize cancer cells. Evaluations in vivo demonstrated that the addition of CRLX101 to standard chemoradiotherapy significantly increased therapeutic efficacy by inhibiting DNA repair and HIF-1Ī± pathway activation in tumor cells. Notably, CRLX101 was more effective than oxaliplatin at enhancing the efficacy of chemoradiotherapy, with CRLX101 and 5-fluorouracil (5-FU) producing the highest therapeutic efficacy. Gastrointestinal toxicity was also significantly lower for CRLX101 compared to CPT when combined with radiotherapy. Our results offer a preclinical proof of concept for CRLX101 as a modality to improve the outcome of neoadjuvant chemoradiotherapy for rectal cancer treatment, in support of ongoing clinical evaluation of this agent (LCC1315 {"type":"clinical-trial","attrs":{"text":"NCT02010567","term_id":"NCT02010567"}}NCT02010567)

    Real-world Use of Mold-Active Triazole Prophylaxis in the Prevention of Invasive Fungal Diseases: Results From a Subgroup Analysis of a Multicenter National Registry

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    BACKGROUND: Antifungal prophylaxis can prevent invasive fungal diseases (IFDs) in high-risk, immunocompromised patients. This study assessed the real-world use of mold-active triazoles (MATs) for the prevention of IFDs. METHODS: This subgroup analysis of a multicenter, observational, prospective registry in the United States from March 2017 to April 2020 included patients who received MATs for prophylaxis (isavuconazole, posaconazole, and voriconazole) at study index/enrollment. The primary objective was to describe patient characteristics and patterns of MAT use. Exploratory assessments included the frequency of breakthrough IFDs and MAT-related adverse drug reactions (ADRs). RESULTS: A total of 1177 patients (256 isavuconazole, 397 posaconazole, 272 voriconazole, and 252 multiple/sequenced MATs at/after index/enrollment) were included in the prophylaxis subgroup analysis. Patient characteristics were similar across MAT groups, but risk factors varied. Hematological malignancy predominated (76.5%) across all groups. Breakthrough IFDs occurred in 7.1% (73/1030) of patients with an investigator\u27s assessment (5.0% [11/221] isavuconazole; 5.3% [20/374] posaconazole; 4.0% [9/226] voriconazole; and 15.8% [33/209] multiple/sequenced MATs). CONCLUSIONS: Breakthrough IFDs were uncommon in patients who received MATs for prophylaxis
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