Experimental assessment of performance and emissions for hydrogen-diesel dual fuel operation in a low displacement compression ignition engine.

The combustion of pure H2 in engines is still troublesome, needing further research and development. Using H2 and diesel in a dual-fuel compression ignition engine appears as a more feasible approach. Here we report an experimental assessment of performance and emissions for a single-cylinder, four-stroke, air-cooled compression ignition engine operating with neat diesel and H2-diesel dual-fuel. Previous studies typically show the performance and emissions for a specific operation condition (i.e. a fixed engine speed and torque) or a limited operating range. Our experiments covered engine speeds of 3000 and 3600 rpm and torque levels of 3 and 7 Nm. An in-house designed and built alkaline cell generated the H2 used for the partial substitution of diesel. Compared with neat diesel, the results indicate that adding H2 decreased the air-fuel equivalence ratio and the Brake Specific Diesel Fuel Consumption Efficiency by around 14-29 % and 4-31 %. In contrast, adding H2 increased the Brake Fuel Conversion Efficiency by around 3-36 %. In addition, the Brake Thermal Efficiency increased in the presence of H2 in the range of 3-37 % for the lower engine speed and 27-43 % for the higher engine speed compared with neat diesel. The dual-fuel mode resulted in lower CO and CO2 emissions for the same power output. The emissions of hydrocarbons decreased with H2 addition, except for the lower engine speed and the higher torque. However, the dual-fuel operation resulted in higher NOx emissions than neat diesel, with 2-6 % and 19-48 % increments for the lower and higher engine speeds. H2 emerges as a versatile energy carrier with the potential to tackle current energy and emissions challenges; however, the dual-fuel strategy requires careful management of NOx emissions.

[Glaucoma Drainage Devices: Tube versus Trabeculectomy Study]. / Glaukomdrainageimplantate und ihre Bedeutung: Tube-versus-Trabekulektomie-Studie.

While trabeculectomy with mitomycin C has previously been the gold standard in penetrating glaucoma surgery, glaucoma drainage implants used early within glaucoma surgery were examined in the course of the tube versus trabeculectomy (TVT) study. Glaucoma drainage implants are now being used earlier, as materials are tissue-compatible and surgery has been improved. While in the past, the use of such implants was often carried out after multiple preoperations, implants are now being used at an earlier stage. Glaucoma drainage implants are typically still used in the pseudophakic eye, where 1-2 glaucoma preoperations (e.g. trabeculectomy) have already been performed.

The validity of self-reported likelihood of HIV infection among the general population in rural Malawi.

BACKGROUND: Understanding HIV risk perception is important for designing appropriate strategies for HIV/AIDS prevention, because these interventions often rely on behaviour modification. A key component of HIV risk perception is the individual's own assessment of HIV status, and the extent to which this assessment is correct. However, this issue has received limited attention. OBJECTIVES: To examine the validity of self-reported likelihood of current HIV infection among the general population in rural Malawi. METHODS: As part of a panel household survey, data on behaviour and biomarkers were collected for a population-based sample of approximately 3000 respondents in rural Malawi aged > or = 15 years. Information on self-assessed likelihood of currently having HIV was collected by survey interview. Saliva was obtained from all consenting respondents to assess actual HIV status. RESULTS: Of 2299 survey respondents who assessed their likelihood of being infected with HIV at the time of the survey, 71% were accurate. Most incorrect assessments (88%) were due to respondents overestimating (rather than underestimating) their likelihood of being infected with HIV. Women were less likely than men to correctly assess their HIV status. The two most important predictors of false-positive responses were marital status and self-reported health. CONCLUSIONS: Self-reports of HIV infection were generally valid. Most invalid self-reports were due to overestimating the risk of having HIV. The implications of this finding are highlighted, as they pertain to the design of HIV prevention interventions and the expansion of HIV counselling, testing and treatment programmes in developing countries.

Endarterectomía carotídea con anestesia local: estudio de 22 casos / Carotid endarterectomy under local anesthesia

Se presenta un estudio descriptivo de 22 casos de endarterectomia carotidea con anestesia local en la Fundacion Santa Fe de Bogota. Se analizan los resultados que muestran una baja morbilidad postoperatoria y ausencia de mortalidad relacionada con el procedimiento. En pacientes de alto riesgo quirurgico y anestesico, esta tecnica es de práctica sencilla y el tratamiento intra y postoperatorio no presenta mayores dificultades.

[Acquired immunodeficiency syndrome (AIDS) in Lubumbashi. Clinical and epidemiological observations]. / Le syndrome d'immunodéficience acquise (SIDA) a Lubumbashi. Observations cliniques et épidémiologiques.

26 AIDS cases (13 males and 13 females) have been noticed in the internal medicine service of the Lubumbashi University Clinics, town at the boundary of the south-east of Zaïre. The clinical data are conventional: only heterosexual transmission seems prevalent. The shortage of HIV diagnosis means restrain larger survey, but 5 to 7% of blood givers are AIDS carriers. The risk of AIDS dissemination is real, even in rural areas of some regions with permanent connections of larger urban centres.

PIP: Observation of 13 male and 13 female AIDS patients hospitalized in the internal medicine service at the Lubumbashi University Clinics between June 1985-October 1987 indicates that AIDS is a threat in other large cities of Zaire besides Kinshasa. Patient ages ranged from 14 to 65 and averaged 35. All 26 experienced profound weight loss, 17 had chronic diarrhea, 10 had fevers, and 10 had pneumathies. 5 had esophageal moniliasis, 2 had dermatoses, 1 had meningeal cryptococcosis, 1 had Kaposi's sarcoma, 1 had shingles, and 1 had salmonellosis. ELISA tests were administered in only 16 cases due to their cost. 17 of the patients were from Lubumbashi.