719 research outputs found

    The Concept Design of a Split Flow Liquid Hydrogen Turbopump

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    An initial design of a split flow liquid hydrogen turbopump for the Dual Expander Aerospike Nozzle (DEAN) upper stage engine was completed. The engine nozzle is an annular aerospike. The engine cycle requires a combustion chamber pressure of 1,740 psia. The DEAN is designed to deliver 57,200 lbf of thrust and 472 seconds of Isp. The turbopump design was completed using a meanline software tool. The design consists of a single piece rotor, with a two-stage pump and radial inflow turbine. The turbopump flow rates are 15.1 and 7.55 lbm/s into the first and second stage, respectively. The first and second stage pumps use unshrouded impellers. An interstage transfer models the fluid split flow. The fluid for each stage exits through a volute. The first and second stage impeller hub-tip ratios are 0.3 and 0.35, respectively. The turbine is a full admission reaction type. At the design condition, the turbine delivers 3,607 horsepower at a total pressure ratio of 1.84

    Relationship between protein biomarkers of chemotherapy response and microsatellite status, tumor mutational burden and PD-L1 expression in cancer patients.

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    Chemotherapy and checkpoint inhibitor immunotherapies are increasingly used in combinations. We determined associations between the presence of anti-PD-1/PD-L1 therapeutic biomarkers and protein markers of potential chemotherapy response. Data were extracted from a clinical-grade testing database (Caris Life Sciences; February 2015 through November 2017): immunotherapy response markers (microsatellite instability-high [MSI-H], tumor mutational burden-high [TMB-H], and PD-L1 protein expression) and protein chemotherapy response markers (excision repair complementation group 1 [ERCC1], topoisomerase 1 [TOPO1], topoisomerase 2 [TOP2A], thymidylate synthase [TS], tubulin beta 3 [TUBB3], ribonucleotide reductase regulatory subunit M1 [RRM1] and O-6-methyl guanine DNA methyltransferase [MGMT]). Relationships were determined by the Mantel-Haenszel chi-squared test or Fischer's exact tests. Overall, 28,034 patients representing a total of 40 tumor types were assessed. MSI-H was found in 3.3% of patients (73% were also TMB-H), TMB-H, 8.4% (28.3% were also MSI-H) and PD-L1 expression in 11.0% of patients (5.1% were also MSI-H; 16.4% were also TMB-H). Based on concurrent biomarker expression, combinations of immunotherapy with platinum (ERCC1 negativity) or with doxorubicin, epirubicin or etoposide (TOP2A positivity) have a higher probability of response, whereas combinations with irinotecan or topotecan (TOPO1 positivity), with gemcitabine (RRM1 negativity), and fluorouracil, pemetrexed or capecitabine (TS negativity) may be of less benefit. The potential for immunotherapy and taxane (TUBB3 negativity) combinations is present for MSI-H but not TMB-H or PD-L1-expressing tumors; for temozolomide and dacarbazine (MGMT negative), PD-L1 is frequently coexpressed, but MSI-H and TMB-H are not associated. Protein markers of potential chemotherapy response along with next-generation sequencing for immunotherapy response markers can help support rational combinations as part of an individualized, precision oncology approach

    Prosperity prospects in contested forest areas: evidence from community forestry development in Guatemala and Nicaragua

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    Tropentag, September 18-21, 2016, Vienna, Austria “Solidarity in a competing world — fair use of resources” Prosperity Prospects in Contested Forest Areas: Evidence from Community Forestry Development in Guatemala and Nicaragua Dietmar Stoian 1 , Aldo Rodas 2 , Jessenia Arguello 3 1 Bioversity International, Healthy Diets from Sustainable Food Systems Initiative, France 2 Ministry of Agriculture and Livestock, Guatemala, Natural Resources and Agrotourism, 3 Independent Consultant, Abstract Community forestry is carried out under diverse institutional, environmental, and socio-economic conditions. Local communities may have de jure rights to forest resources, but de facto protection is often weak. This study focuses on 25-year community concessions in the Maya Biosphere Reserve (MBR) in Guatemala and indigenous territories in the North Caribbean Coast Autonomous Region (RACCN), Nicaragua. In both cases, communities are struggling to enforce their rights as powerful external groups seek to expand cattle ranching, cash crops, tourism, and oil exploration. We found evidence that community forestry can generate significant socio-economic benefits that, along with contributions to forest conservation, substantiate the communities’ claim for strengthened and extended community forest stewardship. We selected six community forest enterprises (CFEs) along a business development gradient and assessed their context, economic viability, and livelihood benefits among randomly selected CFE members (n=180). Adopting an asset lens, we determined human, social, natural, physical and financial capital endowments at household and enterprise levels. Enterprise assets varied widely, both within and across countries. CFEs were well endowed with natural capital (7,000–54,000 ha of broadleaf forests) but highly dependent on precious woods, such as mahogany ( Swietenia macropylla ) or andiroba ( Carapa guianensis ). Human capital was sufficiently developed for managing forests, but less so for processing wood and doing business. Social capital has been built in Guatemala through internal organisation, bringing CFEs under the umbrella of a regional association, and developing relationships with buyers. In Nicaragua, however, building of social capital has been insufficient for inducing a self-sustaining process of CFE development. Physical capital for logging and wood processing was moderate but, in Guatemala, conditions facilitate significant value adding. CFEs there were profitable, while those in the RACCN struggled to break even. Household assets varied widely but, in the MBR, we found evidence that forest-based income can lift people out of poverty. Our analyses reveal that critical success factors for community forestry to reduce poverty, conserve forests and enhance equity are: secure long-term forest usufruct rights or ownership, efficient business organisation, credible advocacy, a conducive service environment, and differentiated opportunities for women, men and youth

    Epidemiology and control of Salmonella in the pork production chain: the approach in a high prevalence country (Spain)

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    The present study summarises the insights yielded by different studies focused on the epidemiology of the infection by Salmonella through the pig production (breeders, finishers and post-farm stages). The final objective is to determine the best strategies for successful control of Salmonella in a highly prevalent country such as Spain. The study in breeders evidenced a high seroprevalence. There were differences among some of the 10 most common serotypes detected in breeders compared to previous studies in finishers, although the two most common were shared by both populations. Type of feed and type of floor were the factors associated to the presence of Salmonella. A Salmonella Typhimurium inactivated vaccine and two organic acids demonstrated to be good tools to reduce the prevalence in finishers. Finally a study of the contamination in post-farm stages evidenced the high contamination of transport, lairage and the contamination of the slaughter line, accounting for 70% of carcass cross-contamination

    Apoptosis-Inducing TNF Superfamily Ligands for Cancer Therapy

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    Cancer is a complex disease with apoptosis evasion as one of its hallmarks; therefore, apoptosis induction in transformed cells seems a promising approach as a cancer treatment. TNF apoptosis-inducing ligands, which are naturally present in the body and possess tumoricidal activity, are attractive candidates. The most studied proteins are TNF-α, FasL, and TNF-related apoptosis-inducing ligand (TRAIL). Over the years, different recombinant TNF family-derived apoptosis-inducing ligands and agonists have been designed. Their stability, specificity, and half-life have been improved because most of the TNF ligands have the disadvantages of having a short half-life and affinity to more than one receptor. Here, we review the outlook on apoptosis-inducing ligands as cancer treatments in diverse preclinical and clinical stages and summarize strategies of overcoming their natural limitations to improve their effectiveness

    The Effect of Channel Errors in the Differential Pulse-Code-Modulation Transmission of Sampled Imagery

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    This Paper Presents an Analysis, Simulation, and Discussion of the Effects of Communication Errors on Four-Bit Differential Pulse-Code Modulation (DPCM) Sampled Imagery. Simulations Are Presented that Describe the Effects of Inserting Periodic PCM Updates in Order to Correct Communication Errors in the DPCM Transmission of Photographic Scenes that Have Been Scanned and Sampled at the Nyquist Rate. Copyright © 1971 by the Institute of Electrical and Electronics Engineers, Inc

    Diplomado Gestión de Riesgo para la adaptación ante el cambio climático Módulo 03: Economia y Cambio Climatico

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    Nuestro país está situado en una región donde hay tiempos que se padece por sequía y se pierden las cosechas, deslizamientos de tierras, derrumbes y tiempos en que las lluvias y los huracanes causan grandes desastres a la población, tal es el caso de los daños que ocasionó el paso del huracán Félix por las comunidades de la región autónoma del atlántico norte, provocó inundaciones en muchas comunidades con el desbordamiento de los ríos, cauces y lagunas, destrucción de calles, camino y carreteras de todo tiempo, impidiendo la comunicación terrestre, contaminación de pozos, para el consumo de agua potable, destrucción del bosque, afectación a la vegetación, mortalidad de animales silvestres y caseros(vaca, gallinas, caballos, cerdos etc), como también la perdida de seres humanos y otros daños, lo que nos permitió comprender el grado de vulnerabilidad a la que estamos sometidos ante fenómenos naturales. Está demostrado que los fenómenos de índole natural no se puede cambiar, pero se pueden reducir las vulnerabilidades para que los daños que estas ocasionen sean menos, de manera que es necesario que los gobiernos y la población se preparan para enfrentarlos y buscar alternativas que sean amigables con el ambiente y contribuya a la reducción del riesgo; desde esta perspectiva la universidad URACCAN a través del Instituto de recursos naturales, medio ambiente y desarrollo sostenible (IREMADES) en colaboración con la Cruz Roja Nicaragüense /Cruz Roja Holandesa por medio del proyecto ̈Reducción de la Vulnerabilidad de las Comunidades, relacionadas a los efectos del Cambio Climático en la Zona Norte de Nicaragua ̈ implementar el Diplomado Comunitario en Gestión Comunitaria para la Adaptación al Cambio Climático, encaminado a consolidar las capacidades de los recursos humanos de funcionarios institucionales y actores claves que están vinculado con el desarrollo social, económico y ambiental de los municipio de la RAAN, con el ánimo de articular estrategias locales en función de implementar mecanismos de adaptación al cambio climático y la reducción del riesgo

    Pharmacokinetics, thrombogenicity and safety of a double viral inactivated factor IX concentrate compared with a prothrombin complex concentrate

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    Therapeutic options for developing countries have to assure an optimum safety and efficacy and low-cost antihaemophilic concentrates. A single blind randomized crossover study was carried out in 12 previously treated HB patients, comparing the pharmacokinetics (PK), thrombogenicity (TG) and safety of two plasma-derived double-inactivated (solvent/detergent heating at 100?C, 30 min) factor IX (FIX) concentrates, UMAN COMPLEX DI (product A) [plasma-derived prothrombin concentrates (PCC)] and a high purity FIX concentrate AIMAFIX DI (product B, HPFIX). In a non-bleeding state, they received one single intravenous dose 50 IU FIX kg−1 of PCC or HPFIX, and after a wash-out period of 14 days, the other product. We evaluated acute tolerance and determined PK parameters based on FIX levels measured over a 50 h postinfusion period. We studied fibrinogen, platelets, antithrombin, F1 + 2, TAT, D-dimer, over a 360 min postinfusion period. Ten cases remained in on-demand treatment for 6 months, five with PCC and five with HPFIX. PK and anti-FIX inhibitors were repeated at 3 and 6 months. No inhibitors were detected. PK values (PCC vs. HPFIX): clearence (CL; mL h−1 kg−1) 5.2 ? 1.4 vs. 6.5 ? 1.4; the volume of distribution at steady state (mL kg−1) 154.9 ? 54.9 vs. 197.5 ? 72.5; mean residence time (h) 29.7 ? 8.1 vs. 30.7 ? 9.2; T1/2 (h) 22.3 ? 7 vs. 23.5 ? 12.3; incremental recovery (IR; U dL−1 U−1 kg−1) 0.96 ? 0.17 vs. 0.76 ? 0.13. HPFIX showed significant lower IR and higher CL. There were no differences in PK at 3 and 6 months. In TG, significant increments in TAT and F1 + 2 at 30 min and 6 h were found with PCC. Product B PK results agrees with reported results for other HPFIX preparations. Use of PCC product A has to consider its thrombogenic activity
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