18,722 research outputs found
Activity of oxantel pamoate monotherapy and combination chemotherapy against Trichuris muris and hookworms : revival of an old drug
BACKGROUND: It is widely recognized that only a handful of drugs are available against soil-transmitted helminthiasis, all of which are characterized by a low efficacy against Trichuris trichiura, when administered as single doses. The re-evaluation of old, forgotten drugs is a promising strategy to identify alternative anthelminthic drug candidates or drug combinations. METHODOLOGY: We studied the activity of the veterinary drug oxantel pamoate against Trichuris muris, Ancylostoma ceylanicum and Necator americanus in vitro and in vivo. In addition, the dose-effect of oxantel pamoate combined with albendazole, mebendazole, levamisole, pyrantel pamoate and ivermectin was studied against T. muris in vitro and additive or synergistic combinations were followed up in vivo. PRINCIPAL FINDINGS: We calculated an ED50 of 4.7 mg/kg for oxantel pamoate against T. muris in mice. Combinations of oxantel pamoate with pyrantel pamoate behaved antagonistically in vitro (combination index (CI) = 2.53). Oxantel pamoate combined with levamisole, albendazole or ivermectin using ratios based on their ED50s revealed antagonistic effects in vivo (CI = 1.27, 1.90 and 1.27, respectively). A highly synergistic effect (CI = 0.15) was observed when oxantel pamoate-mebendazole was administered to T. muris-infected mice. Oxantel pamoate (10 mg/kg) lacked activity against Ancylostoma ceylanicum and Necator americanus in vivo. CONCLUSIONSIGNIFICANCE: Our study confirms the excellent trichuricidal properties of oxantel pamoate. Since the drug lacks activity against hookworms it is necessary to combine oxantel pamoate with a partner drug with anti-hookworm properties. Synergistic effects were observed for oxantel pamoate-mebendazole, hence this combination should be studied in more detail. Since, of the standard drugs, albendazole has the highest efficacy against hookworms, additional investigations on the combination effect of oxantel pamoate-albendazole should be launche
Comparative Analysis of Resilience by Supply Network Structure
This research applies Kim, et al.’s (2015) supply network structure archetypes to case data related to two disruptions in three industries in Brazil. A total of seven supply networks were studied, through in-depth interviews and archival documents. The findings suggest that there may be additional supply network structures that are relevant. Centralization appears to be a function of the size of the focal firm. There was evidence of an evolution of supply network structures with focal firm size
Develop a model of project management about consulting in water resources based on guidelines of PMBOK
El artÃculo presenta un modelo de gestión de proyectos que aplica y ajusta los procesos planteados para el alcance, el tiempo y los costos de metodologÃas tradicionales en proyectos de recursos hÃdricos de consultorÃa. El modelo es válido durante la fase precontractual cuando el proyecto es una propuesta y la fase contractual entendida como la ejecución del objeto del contrato bajo las condiciones de la entidad contratante. El modelo como metodologÃa plantea en la fase precontractual la participación del grupo directivo y técnico con el objeto de realizar una evaluación de entregables que conduzca a una estimación de costos más precisa. Mientras en la fase contractual se consideró la integración y participación de un profesional de control proyecto con el grupo especialista y directivo para acompañar y consolidar los recursos a asignar y fijar el listado de entregables que genere las actividades, la EDT, el cronograma y el presupuesto a través del uso de la herramienta MS Project, de igual manera este profesional realiza el control del avance del proyecto a través de la técnica del valor ganado. Como resultado relevante se tiene que los entregables y sus recursos deben ser realizados por un grupo multidisciplinario, y a su vez integrados por un profesional de control proyecto para obtener un único alcance, presupuesto y cronograma aprobado por la entidad contratante, con el cual se cree una lÃnea base y un control mensual que se reporte de forma oportuna a la gerencia.This paper discusses a project management model that applies and adjusts traditional processes and methodologies in consulting projects of water resources. This adapted model is valid during the pre-contractual stage when the project is just a proposal, and contractual stage, that is during ejecution stage, all subject to the conditions of the procuring entity. This one can be used during steps of prefractabilty, factibility, basic designs and detailed designs. It is proposed that during pre-contractual stage, management team and technical one do a evaluation of project products to obtain a more accurate cost estimation. As during contractual stage, it was considered the position of control project. This member of management team must follow and consolidate all assigned resources to the project, also he must to establish the list of products and check the WBS, schedule and budget by aid of MS Project. Him must control project progress through the technique of earn value. As a relevant result, the resources and products of project must be defined by a multidisciplinary team, and integrated by professional control project to obtain the scope, schedule and budget approved by the contracting entity. Control project must establish a project base line and make a monthly control to report to management team
Multi-sensor system using plastic optical fibers for intrinsically safe level measurements
A system for measuring liquid level in multiple tanks using optical fibe technology has been developed. Oil fiel service industry or any sector requiring liquid level measurements in flammabl atmospheres can be benefite from this intrinsically safe technology. The device used a single lens for the emitting and receiving fibe and it is based on amplitude variations as a function of the liquid distance and not in time of fligh or phase detection. Being the firs fiber-opti liquid level sensor with those characteristics for long ranges (>200 cm). A simple model to describe their behavior has been derived and tested on two prototypes. A Monte-Carlo method is used to fi the experimental data and obtain the model parameters. High accuracy between experimental data and fitte curve is obtained. The prototypes have a good linearity, better than 1.5% FS (full scale). Sensor heads are made of plastic optical fiber (POF) that are easy to handle, flexible and economical. They are excited by 650 nm lasers, housed in ST-connectors to obtain compact and rough prototypes. Optical multiplexing is used to increase the measuring safety area. Frequency division multiplexing is used to address each sensor head. A discussion about the influenc of tilts and aberrations is also included.Publicad
Recurrent Coronal Jets Induced by Repetitively Accumulated Electric Currents
Three extreme-ultraviolet (EUV) jets recurred in about one hour on 2010
September 17 in the following magnetic polarity of active region 11106. The EUV
jets were observed by the Atmospheric Imaging Assembly (AIA) on board the Solar
Dynamics Observatory (SDO). The Helioseismic and Magnetic Imager (HMI) on board
SDO measured the vector magnetic field, from which we derive the magnetic flux
evolution, the photospheric velocity field, and the vertical electric current
evolution. The magnetic configuration before the jets is derived by the
nonlinear force-free field (NLFFF) extrapolation.
We derive that the jets are above a pair of parasitic magnetic bipoles which
are continuously driven by photospheric diverging flows. The interaction drove
the build up of electric currents that we indeed observed as elongated patterns
at the photospheric level. For the first time, the high temporal cadence of HMI
allows to follow the evolution of such small currents. In the jet region, we
found that the integrated absolute current peaks repetitively in phase with the
171 A flux evolution. The current build up and its decay are both fast, about
10 minutes each, and the current maximum precedes the 171 A by also about 10
minutes. Then, HMI temporal cadence is marginally fast enough to detect such
changes.
The photospheric current pattern of the jets is found associated to the
quasi-separatrix layers deduced from the magnetic extrapolation. From previous
theoretical results, the observed diverging flows are expected to build
continuously such currents. We conclude that magnetic reconnection occurs
periodically, in the current layer created between the emerging bipoles and the
large scale active region field. It induced the observed recurrent coronal jets
and the decrease of the vertical electric current magnitude.Comment: 10 pages, 7 figures, accepted for publication in A&
- …