Perfomance evaluation of a direct injection engine using different blends of soybean (Glycine max) methyl biodiesel

Diesel fuel is used widely in Brazil and worldwide. On the other hand, the growing environmental awareness leads to a greater demand for renewable energy resources. Thus, this study aimed to evaluate the use of different blends of soybean (Glycine max) methyl biodiesel and diesel in an ignition compression engine with direct injection fuel. The tests were performed on an electric eddy current dynamometer, using the blends B10, B50 and B100, with 10; 50 e 100% of biodiesel, respectively, in comparison to the commercial diesel B5, with 5% of biodiesel added to the fossil diesel. The engine performance was analyzed trough the tractor power take off (PTO) for each fuel, and the best results obtained for the power and the specific fuel consumption, respectively, were: B5 (44.62 kW; 234.87 g kW-1 h-1); B10 (44.73 kW; 233.78 g kW-1 h-1); B50 (44.11 kW; 250.40 g kW-1 h-1) e B100 (43.40 kW; 263.63 g kW-1 h-1). The best performance occurred with the use of B5 and B10 fuel, without significant differences between these blends. The B100 fuel showed significant differences compared to the other fuels.O óleo diesel combustível é utilizado em grande escala no País e no mundo. Por outro lado, a crescente conscientização ambiental acarreta em maior demanda por recursos energéticos renováveis. Assim, o presente trabalho objetivou avaliar o uso de diferentes misturas de biodiesel metílico de soja (Glycine max) e diesel mineral em um motor de ignição por compressão e injeção direta de combustível. Os procedimentos de ensaio foram realizados em um dinamômetro elétrico de correntes parasitas, utilizando as proporções de mistura B10, B50 e B100, com 10; 50 e 100% de biodiesel, respectivamente, em comparação ao diesel comercial B5, com 5% de biodiesel adicionado ao diesel fóssil. O desempenho do motor foi analisado através da tomada de potência do trator (TDP) para cada mistura, sendo que os melhores resultados obtidos para potência e consumo específico de combustível, respectivamente, foram: B5 (44,62 kW; 234,87 g kW-1 h-1); B10 (44,73 kW; 233,78 g kW-1 h-1); B50 (44,11 kW; 250,40 g kW-1 h-1) e B100 (43,40 kW; 263,63 g kW-1 h-1 ). O melhor desempenho ocorreu sob o uso dos combustíveis B5 e B10, sem diferenças significativas entre essas misturas. Já o combustível B100 apresentou diferenças significativas em relação aos demais combustíveis

The Pleiotropic CymR Regulator of Staphylococcus aureus Plays an Important Role in Virulence and Stress Response

We have characterized a novel pleiotropic role for CymR, the master regulator of cysteine metabolism. We show here that CymR plays an important role both in stress response and virulence of Staphylococcus aureus. Genes involved in detoxification processes, including oxidative stress response and metal ion homeostasis, were differentially expressed in a ΔcymR mutant. Deletion of cymR resulted in increased sensitivity to hydrogen peroxide-, disulfide-, tellurite- and copper-induced stresses. Estimation of metabolite pools suggests that this heightened sensitivity could be the result of profound metabolic changes in the ΔcymR mutant, with an increase in the intracellular cysteine pool and hydrogen sulfide formation. Since resistance to oxidative stress within the host organism is important for pathogen survival, we investigated the role of CymR during the infectious process. Our results indicate that the deletion of cymR promotes survival of S. aureus inside macrophages, whereas virulence of the ΔcymR mutant is highly impaired in mice. These data indicate that CymR plays a major role in virulence and adaptation of S. aureus for survival within the host

Efficient discovery of anti-inflammatory small-molecule combinations using evolutionary computing

The control of biochemical fluxes is distributed, and to perturb complex intracellular networks effectively it is often necessary to modulate several steps simultaneously. However, the number of possible permutations leads to a combinatorial explosion in the number of experiments that would have to be performed in a complete analysis. We used a multiobjective evolutionary algorithm to optimize reagent combinations from a dynamic chemical library of 33 compounds with established or predicted targets in the regulatory network controlling IL-1β expression. The evolutionary algorithm converged on excellent solutions within 11 generations, during which we studied just 550 combinations out of the potential search space of ~9 billion. The top five reagents with the greatest contribution to combinatorial effects throughout the evolutionary algorithm were then optimized pairwise. A p38 MAPK inhibitor together with either an inhibitor of IκB kinase or a chelator of poorly liganded iron yielded synergistic inhibition of macrophage IL-1β expression. Evolutionary searches provide a powerful and general approach to the discovery of new combinations of pharmacological agents with therapeutic indices potentially greater than those of single drugs

The effects of methionine acquisition and synthesis on Streptococcus pneumoniae growth and virulence

Extent: 14 p.Bacterial pathogens need to acquire nutrients from the host, but for many nutrients their importance during infection remain poorly understood. We have investigated the importance of methionine acquisition and synthesis for Streptococcus pneumoniae growth and virulence using strains with gene deletions affecting a putative methionine ABC transporter lipoprotein (Sp_0149, metQ) and/or methionine biosynthesis enzymes (Sp_0585 - Sp_0586, metE and metF). Immunoblot analysis confirmed MetQ was a lipoprotein and present in all S. pneumoniae strains investigated. However, vaccination with MetQ did not prevent fatal S. pneumoniae infection in mice despite stimulating a strong specific IgG response. Tryptophan fluorescence spectroscopy and isothermal titration calorimetry demonstrated that MetQ has both a high affinity and specificity for L-methionine with a KD of ~ 25 nM, and a DmetQ strain had reduced uptake of C14-methionine. Growth of the ΔmetQ/ΔmetEF strain was greatly impaired in chemically defined medium containing low concentrations of methionine and in blood but was partially restored by addition of high concentrations of exogenous methionine. Mixed infection models showed no attenuation of the ΔmetQ, ΔmetEF and ΔmetQ/DmetEF strains in their ability to colonise the mouse nasopharnyx. In a mouse model of systemic infection although significant infection was established in all mice, there were reduced spleen bacterial CFU after infection with the ΔmetQ/ΔmetEF strain compared to the wild-type strain. These data demonstrate that Sp_0149 encodes a high affinity methionine ABC transporter lipoprotein and that Sp_0585 – Sp_0586 are likely to be required for methionine synthesis. Although Sp_0149 and Sp_0585-Sp_0586 make a contribution towards full virulence, neither was essential for S. pneumoniae survival during infection.Shilpa Basavanna, Suneeta Chimalapati, Abbas Maqbool, Bruna Rubbo, Jose Yuste, Robert J. Wilson, Arthur Hosie, Abiodun D. Ogunniyi, James C. Paton, Gavin Thomas and Jeremy S. Brow

Estimating the burden of selected non-communicable diseases in Africa: a systematic review of the evidence

Background The burden of non-communicable diseases (NCDs) is rapidly increasing globally, and particularly in Africa, where the health focus, until recently, has been on infectious diseases. The response to this growing burden of NCDs in Africa has been affected owing to a poor understanding of the burden of NCDs, and the relative lack of data and low level of research on NCDs in the continent. Recent estimates on the burden of NCDs in Africa have been mostly derived from modelling based on data from other countries imputed into African countries, and not usually based on data originating from Africa itself. In instances where few data were available, estimates have been characterized by extrapolation and over-modelling of the scarce data. It is therefore believed that underestimation of NCDs burden in many parts of Africa cannot be unexpected. With a gradual increase in average life expectancy across Africa, the region now experiencing the fastest rate of urbanization globally, and an increase adoption of unhealthy lifestyles, the burden of NCDs is expected to rise. This thesis will, therefore, be focussing on understanding the prevalence, and/or where there are available data, the incidence, of four major NCDs in Africa, which have contributed highly to the burden of NCDs, not only in Africa, but also globally. Methods I conducted a systematic search of the literature on three main databases (Medline, EMBASE and Global Health) for epidemiological studies on NCDs conducted in Africa. I retained and extracted data from original population-based (cohort or cross sectional), and/or health service records (hospital or registry-based studies) on prevalence and/or incidence rates of four major NCDs in Africa. These include: cardiovascular diseases (hypertension and stroke), diabetes, major cancer types (cervical, breast, prostate, ovary, oesophagus, bladder, Kaposi, liver, stomach, colorectal, lung and non-Hodgkin lymphoma), and chronic respiratory diseases (chronic obstructive pulmonary disease (COPD) and asthma). From extracted crude prevalence and incidence rates, a random effect meta-analysis was conducted and reported for each NCD. An epidemiological model was applied on all extracted data points. The fitted curve explaining the largest proportion of variance (best fit) from the model was further applied. The equation generated from the fitted curve was used to determine the prevalence and cases of the specific NCD in Africa at midpoints of the United Nations (UN) population 5-year age-group population estimates for Africa. Results From the literature search, studies on hypertension had the highest publication output at 7680, 92 of which were selected, spreading across 31 African countries. Cancer had 9762 publications and 39 were selected across 20 countries; diabetes had 3701 publications and 48 were selected across 28 countries; stroke had 1227 publications and 19 were selected across 10 countries; asthma had 790 publications and 45 were selected across 24 countries; and COPD had the lowest output with 243 publications and 13 were selected across 8 countries. From studies reporting prevalence rates, hypertension, with a total sample size of 197734, accounted for 130.2 million cases and a prevalence of 25.9% (23.5, 34.0) in Africa in 2010. This is followed by asthma, with a sample size of 187904, accounting for 58.2 million cases and a prevalence of 6.6% (2.4, 7.9); COPD, with a sample size of 24747, accounting for 26.3 million cases and a prevalence of 13.4% (9.4, 22.1); diabetes, with a sample size of 102517, accounting for 24.5 million cases and a prevalence of 4.0% (2.7, 6.4); and stroke, with a sample size of about 6.3 million, accounting for 1.94 million cases and a prevalence of 317.3 per 100000 population (314.0, 748.2). From studies reporting incidence rates, stroke accounted for 496 thousand new cases in Africa in 2010, with a prevalence of 81.3 per 100000 person years (13.2, 94.9). For the 12 cancer types reviewed, a total of 775 thousand new cases were estimated in Africa in 2010 from registry-based data covering a total population of about 33 million. Among women, cervical cancer and breast cancer had 129 thousand and 81 thousand new cases, with incidence rates of 28.2 (22.1, 34.3) and 17.7 (13.0, 22.4) per 100000 person years, respectively. Among men, prostate cancer and Kaposi sarcoma closely follows with 75 thousand and 74 thousand new cases, with incidence rates of 14.5 (10.9, 18.0) and 14.3 (11.9, 16.7) per 100000 person years, respectively. Conclusion This study suggests the prevalence rates of the four major NCDs reviewed (cardiovascular diseases (hypertension and stroke), diabetes, major cancer types, and chronic respiratory diseases (COPD and asthma) in Africa are high relative to global estimates. Due to the lack of data on many NCDs across the continent, there are still doubts on the true prevalence of these diseases relative to the current African population. There is need for improvement in health information system and overall data management, especially at country level in Africa. Governments of African nations, international organizations, experts and other stakeholders need to invest more on NCDs research, particularly mortality, risk factors, and health determinants to have evidenced-based facts on the drivers of this epidemic in the continent, and prompt better, effective and overall public health response to NCDs in Africa

Modeling Gerotor Pump Performance in Artificial Lift for Single-Phase and Multiphase Conditions

Summary Gerotors are positive displacement pumps and candidates for artificial lift in the oil and gas industry. This study evaluates the performance of a unique gerotor pump design under single-phase and multiphase conditions. The gerotor pump performance is modeled with computational fluid dynamics (CFD) to develop a virtual prototype of the multiphase performance behavior. The gas/liquid flow is modeled using a homogeneous multiphase approach. A prototype 3D model of a 400 series gerotor pump suitable for application in a 5½-in. casing is developed. The pump volume displacement is consistent with that to be used in subsequent laboratory experimental tests and field prototype testing. Transient 3D CFD is used to simulate the gerotor pump performance under single-phase and multiphase flow conditions. The complex gerotor motion is modeled in CFD using a dynamic meshing technique. Pump rotor speeds applicable to the range of testing conditions were applied. The gas and liquid phase properties correspond to mineral oil and air at the prototype test conditions. The results of the gerotor pump performance are presented for single-phase and multiphase conditions over a range of gas volume fractions (GVFs) from 0 to 0.75. The CFD results show that the flow rate decreases approximately linearly with pump differential pressure, which is typical of positive displacement pumps. Pump performance and efficiency curves are developed relating the pump differential pressure and flow rate. The CFD model methodology is presented with consideration to appropriate selection of the numerical methods, multiphase model, mesh design, dynamic mesh motion, and other aspects to improve the reliability of the numerical simulations. For the same differential pressure, increasing the GVF decreases the gerotor total pumping volume rates. The results establish a first baseline for the pumping system for subsequent comparison with physical model testing to ascertain gas/liquid handling capability of the pump for further optimization for field application. This study evaluates and highlights the potential applicability of gerotors as an alternative artificial lift technology for multiphase pumping. This technology with further development in addition to its inherent mechanical simplicity and compactness can serve as a promising candidate for surface and downhole multiphase pressure boosting for production in the oil and gas industry.</jats:p

Physical Performance Testing of a Prototype Gerotor Pump Operating in Liquid and Gas/Liquid Conditions

Summary Gerotors are positive displacement pumps and potential artificial lift options in the oil and gas industry. This study presents the performance characteristics from physical testing of a unique one-stage, equal-walled gerotor pump design operating in oil and oil/air mixtures. The pump was tested at various rotational speeds in a flow loop. The performance results were obtained to ascertain potential design optimizations of the pump before embarking on manufacturing and testing of the field prototype pump. A physical prototype of a one-stage 400 series gerotor pump, suitable for application in a 5.5-in. casing, was designed, manufactured, assembled, and tested. Mineral oil and air were used as the operating media. For given pump outlet valve settings, the pump rotational speeds were set to 200, 250, 300, and 350 rev/min. Gas volume fractions (GVFs) at the pump inlet were varied from 0% to the maximum the current pump design could handle. For each test point, the corresponding pump parameters were measured. Dimensionless performance plots were established for obtaining pump performance at other flow conditions. The results showed that pump flow rate decreased with increasing differential pressure, typical of positive displacement pumps. At 200 and 350 rev/min, maximum pump delivery is approximately 190 and 330 B/D of oil, respectively, at zero differential pressure. The pump can supply flow against a differential pressure of up to approximately 5.5 psi at 200 rev/min and 15 psi at 350 rev/min. For the 200 to 350 rev/min speed range, volumetric efficiencies varied from 30 to 73%, whereas the electric power input varied from 145 to 191 W. When pumping oil/air mixtures, the current gerotor pump design can handle 15% GVF maximum, at 250, 300, and 350 rev/min. For certain pump outlet pressures, the total fluid flow rates decreased as the GVF increased to 15%. The volumetric efficiencies at 15% GVF varied from 32 to 53% for the 300 to 350 rev/min speed range, whereas the motor electric power input decreased with increasing GVF up to 15%. In conclusion, increasing the pump rotational speed improves the volumetric efficiency and gas-handling capability of the gerotor pump. These observations will aid in the required design optimization to enhance the performance of the future field prototype gerotor pump. This study presents the capabilities of gerotors as potential artificial lift alternatives to handle liquid and gas/liquid mixtures for boosting applications in oilfield operations. The technology with additional design optimization can be readily integrated into oilfield equipment architecture. The mechanical simplicity of gerotors and their compactness provides a promising artificial lift substitute that may be implemented for downhole or surface production of liquid or gas/liquid mixtures in the oil and gas industry.</jats:p

Gerotor Pump Performance in Artificial Lift for Single-Phase and Multiphase Conditions

Abstract Gerotors are positive displacement pumps and candidates for artificial lift in the oil and gas industry. This study evaluates the performance of a unique gerotor pump design under single and multiphase conditions in a downhole configuration. The gerotor pump performance is modeled with computational fluid dynamics (CFD) to develop a virtual prototype of the multiphase performance behavior prior to physical testing. A prototype 3D model of a 400 series gerotor pump suitable for application in a 5½-in. casing was developed. The pump volume displacement is consistent between the initial laboratory experimental tests and future field testing. A transient 3D CFD was used to simulate the gerotor pump performance under single-phase and multiphase flow conditions. The complex gerotor motion was modeled in CFD using a dynamic meshing technique. Pump rotor speeds applicable to the range of testing conditions were applied. The gas and liquid phase properties correspond to mineral oil and air at the prototype test conditions. The results of the gerotor pump performance are presented for single-phase and multiphase conditions over a range of gas volume fractions (GVFs) from zero to 0.75. The CFD results show that the flow rate decreases approximately linearly with discharge pressure, which is typical of positive displacement pumps. Pump performance and efficiency curves are developed relating the delivery pressure and flow rate. The CFD model methodology is presented with consideration to appropriate selection of the numerical methods, multiphase model, mesh design, dynamic mesh motion, and other aspects to improve the reliability of the numerical simulations. For the same delivery pressure, increasing the GVF decreases the gerotor pumping rates. Recommendations are proposed for improving the multiphase pumping capacity through pump geometry modifications. The modifications effectively tailor the gerotor to improving gas-liquid pumping in specific oil field operating conditions. This study highlights the potential for gerotors as an alternative artificial lift technology for multiphase pumping. This technology with the inherent mechanical simplicity and compactness provides cost-effective surface and downhole multiphase pressure boosting for production in the oil and gas industry.</jats:p

Dynamics of Child Health Services in Nigeria: A Review

Childcare has been identified as an integral aspect of integrated maternal and child health services and is aimed at child health promotion for childhood psychosocial and physical development. This study assessed the dynamics of child health services in Nigeria. This was in relation to Nigeria’s poor child health indices with the view to encouraging standard practices neglected over the years. It targets preventive health services to stem diseases and disability among children while promoting early diagnosis of diseases and prompt treatment. These services encompass the provision of childhood immunization, probing for and identification of handicapped children for early rehabilitation, child health education, and nutrition, promotion of environmental sanitation, and monitoring of developmental milestone through proper feeding. Other child health services include sickle cell prevention services, education of caregivers on the importance and use of oral rehydration therapy, and use of antimalarial treatment, and rehabilitation of already affected children. This is invaluable, especially in regions with developing countries where more than 50% of children die before their fifth birthday.</jats:p