Acclimation of microorganisms for an efficient production of volatile fatty acids and biogas from mezcal vinasses in a dark fermentation process.

Mezcal is an alcoholic artisanal drink made from agave plants in Mexico. Its production causes the generation of wastewater called vinasses, which are highly polluting residues due to its concentration of organic matter as chemical oxygen demand (COD) (35,000-122,000 mg/L) and acidity (pH < 4). Due to their organic content, these residues can be used in dark fermentation to obtain biogas, which is rich in hydrogen. In this work, the acclimation of inoculum by means of a dark fermentation process, in the presence of toxic compounds from mezcal vinasses was studied. The strategy of increasing the initial concentration of vinasse in each treatment cycle in a sequencing batch reactor (SBR) reactor was applied. It was possible to obtain a maximum biogas production of 984 ± 187 mL/L, from vinasses (18,367 ± 1,200 mg COD/L), with an organic matter removal efficiency of 20 ± 1%. A maximum generation of volatile fatty acids (VFA) of 980 ± 538 mg/L equivalent to a production of 74 ± 21% of the influent concentration and removal rate of organic matter of 1,125 ± 234 mg COD/L d-1 equivalent to a removal efficiency of 20 ± 4% was obtained from vinasses with a concentration of 19,648 ± 1,702 mg COD/L.

Mesquite wood chips (Prosopis) as filter media in a biofilter system for municipal wastewater treatment.

The biofiltration system over organic bed (BFOB) uses organic filter material (OFM) to treat municipal wastewater (MWW). This study evaluated the performance of a BFOB system employing mesquite wood chips (Prosopis) as OFM. It also evaluated the effect of hydraulic loading rates (HLRs) in order to achieve the operational parameters required to remove organic matter, suspended material, and pathogens, thus meeting Mexican and US regulations for reuse in irrigation. Two biofilters (BFs) connected in series were installed; the first one aerated (0.62 m(3)air m(-2)h(-1)) and the second one unaerated. The source of MWW was a treatment plant located in Durango, Mexico. For 200 days, three HLRs (0.54, 1.07, and 1.34 m(3)m(-2)d(-1)) were tested. The maximum HLR at which the system showed a high removal efficiency of pollutants and met regulatory standards for reuse in irrigation was 1.07 m(3)m(-2)d(-1), achieving removal efficiencies of biochemical oxygen demand (BOD5) 92%, chemical oxygen demand (COD) 78%, total suspended solids (TSS) 95%, and four log units of fecal coliforms. Electrical conductivity in the effluent ensures that it would not cause soil salinity. Therefore, mesquite wood chips can be considered an innovative material suitable as OFM for BFs treating wastewaters.

Treatment of wastewater from a school in a decentralized filtration system by percolation over organic packing media.

Based on results obtained in the laboratory a WWTP composed of a septic tank and an aerated percolating filter packed with organic media was built for a school. The system can treat 18 m3 d(-1) and was operated with a hydraulic loading rate of 0.078 (m3 m(-2) d(-1). For 360 days different operational conditions including start-up; stabilization; operation with aeration and non aeration; effect of rainy season, breaks from activities due to holidays and restart; were monitored and described in the article. Once stabilized, the system was able to remove, without the need for mechanical aeration, 97% of BOD5, 71% of COD, 93% of TKN, 11% of PO(4-)-P, 95% of TSS, 96% of VSS, in addition to having a removal efficiency of 4 log units of Faecal Coliforms (FC) and 100% helminthes eggs (HE). With this quality, the treated wastewater can be chlorinated and reused to irrigate green areas and/or in toilets. Although sanitary wastewater has a high concentration of Total-N (250 mg L(-1)) and a C/N ratio of less than 1, the system removed 65% of Total-N. Finally it was observed that after non activity periods, there was neither system failure nor the need to re-stabilize the system.

Comparison of bioreactors with different kinds of submerged packed beds for domestic wastewater treatment.

The performance of aerobic submerged packed bed reactors was studied for the treatment of domestic wastewater using different kinds of packing materials with high specific areas (760-1,200 m(2)/m(3)). The tested materials were ceramic spheres, crushed tezontle, grains of high density polyethylene (HDPE), of low density polyethylene (LDPE) and of polypropylene (PP), cubes of polyurethane (PU) and polyethylene tape (SESSIL). The bioreactors were operated in continuous regime, applying organic loads in the range of 0.8-6.0 g COD.m(-2).d(-1). The obtained specific COD removal rates were very similar in all the reactors when they were operated at organic loads up to 2.0 g COD.m(-2).d(-1), after which differences in effectiveness appeared and the best results were determined in the reactors with SESSIL, LDPE and PU. Very low TSS, O&G and turbidity were obtained in all the effluents. The NH(3)-N and TN removals were dependent on the dissolved oxygen (DO) concentration and the removals at DO of 5 mg/l were 84-99% and 61-74% respectively. The best removals were determined in the reactors with PU, SESSIL and LDPE. The reactor with tezontle had also a good performance when operated with loads up to 1.0 g TN.m(-2).d(-1). The best phosphate removals (38-49%) were obtained in the reactors with PU, tezontle, ceramic sheres and SESSIL.

Aeration effect on the efficiency of swine manure treatment in a trickling filter packed with organic materials.

Effect of aeration rate on the removal of organic matter and nitrogen and on the formation of NH3, N2O and N2 was studied for an extensive biofiltration system packed with an organic media, which was used to treat pig manure. The results show high removal of BOD5 and TSS (99 and > or = 98%), independently of the four aeration rate tested (3.4-34 m3/m2 x h). Aeration rate > or = 4.4 m/h resulted in high ammonia stripping during start-up (> or = 1.0 kg NH3-N/m3 of swine manure treated), while using 3.4 m/h only 0.3 kg NH3-N/m3 were stripped. Complete nitrification was achieved after day 100 of operation, except in the biofilter with the lowest aeration rate. Simultaneous denitrification established in all the biofilters. Applying an aeration rate of 9.4 m/h up to 1.2 kg nitrogen was removed in the form of N2 for each m3 of swine manure treated. Contrary to the expectations, N2 formation and release increased with the aeration rate. This particular behaviour seems to be related to the punctual accumulation of water layers inside the biofilters, caused by the air force flowing in the opposite direction to the water flux. N2O production was quite similar in all biofilters (between 0.25-0.36 kg N2O-N/m3 of swine manure treated).

[Enoxaparin for the Treatment of Unstable Angina and Non-ST Segment Elevation Myocardial Infarction: the ENO-INT Study]. / Enoksaparin v lechenii nestabil'noi stenokardii i infarkta miokarda bez pod"emov segmenta ST: issledovanie ENO-INT.

UNLABELLED: AIM. To assess safety and efficacy of enoxaparin in patients with UA/NSTEMI in an open-label, multi-centre, non-comparative study and to compare the results with data from large-scale randomized trials ESSENCE and TIMI-11B. METHODS: Patients hospitalized with a diagnosis of recent UA/NSTEMI were treated with 1 mg/kg enoxaparin every 12 hours for 2-8 days. The composite endpoint of the study was death, myocardial infarction (MI) or recurrent angina at day 15 (or hospital discharge). Minor and major bleedings were recorded. RESULTS: A total of 1902 patients were enrolled in 109 centers across 24 countries, of which 1901 received at least one injection of enoxaparin and 1785 (93.8%) completed the study (follow-up). Throughout the study (day 180) 21.4% of patients underwent at least one revascularization, of which 4.4% were urgent. The incidence of the composite efficacy endpoint was 16.3% after 15 days and 27.9% on day 180, which was comparable with the enoxaparin arm of the ESSENCE/TIMI 11B studies, and lower than the incidence found in the UFH arm of those studies. At day 15 or hospital discharge the occurrence of major and minor haemorrhages was 1.1 and 6.6%, respectively, which was lower than in ESSENCE/TIMI 11B. More bleeding complications (major and minor) were noted in patients aged

Determination of the hydraulic residence time in a trickling biofilter filled with organic matter.

Biofiltration process using peat as media has been shown to be efficient for the treatment of agroindustrial, chemical and municipal effluents. However, determining the hydraulic retention time of this process is difficult due to many factors. Generally tracer techniques are used, but they measure the molecular retention time instead of the hydraulic retention time; and depending on the case, the results can be wrong. In order to contribute to solving this problem, the objective of this research was to find a trustworthy and adequate technique to determine the hydraulic retention time for a process using a very adsorbent filter bed material (peat). An overview of the hydraulic behaviour of a peat bed filter related to their particular structural composition is presented. Then, based on these characteristics, two different techniques to determine the hydraulic retention time were developed and tested. The first, an indirect modified tracing technique and, the second, a direct one which determines the volume of liquid in treatment into the filter bed through the establishment of a relation between the volume of porosity and the volume of empty spaces (or not occupied by liquid) into the filter bed. The results obtained showed that the proposed techniques gave similar results and proved adequate.

Assessing health-related quality of life in cataract patients: the relationship between utility and health-related quality of life measurement.

The relationship between health-related quality of life (HQL) measures and patient preference for their health status was studied. Study subjects consisted of 132 patients at four hospitals who were scheduled for cataract surgery. Generic and disease-specific health status measures were determined in study subjects. The Medical Outcomes Study Short-form 36 (SF-36) item health status instrument was used to measure generic health status and the Visual Function 14 (VF-14) item visual health status instrument was used as the disease-specific health measure. Preference for general health and visual health was measured by assessing utilities assigned by patients to certain health states. Utilities assigned for general health were correlated with all categories of the SF-36 and VF-14 scores. Utilities assigned for visual health were correlated with four categories of the SF-36 (role limitation due to emotional health, general health, physical functioning, and vitality) and VF-14 scores. Utilities assigned for visual health were more strongly correlated with VF-14 scores than generic measures of health. Verbal ratings for visual health were correlated with Snellen visual acuity (SVA) (r = 0.20), utilities assigned for visual health (r = 0.58), VF-14 scores (r = 0.74), all categories of the SF-36 (r values ranging from 0.21 to 0.28), utilities assigned for general health (r = 0.19), and verbal ratings for general health (r = 0.29). Utility measures and verbal ratings for general and visual health were shown to be appropriate HQL measures. These measures were strongly correlated with other established generic and disease-specific health measures and should be included in the array of health status measures.

[Evaluation of health status using Survey SF-36: preliminary results in Mexico]. / Evaluación del estado de salud con la Encuesta SF-36: resultados preliminares en México.

OBJECTIVE: To establish a multidimensional profile of the health status in a population of southeastern Mexico and analyze the psychometric properties of a translation of the SF-36 survey authorized by the International Quality of Life Assessment Project. MATERIAL AND METHODS: The SF-36 was administered to 257 volunteers of a clinic and a control group in a governmental institution. The methodology proposed by the author of the survey to build the health scales was used without modifications. The validity and reliability of the SF-36 adaptation to Mexico was psychometrically analyzed. RESULTS: Eight scales or health concepts related to physical function, physical role, body pain, general health, vitality, social function, emotional role and mental health were constructed. In the health service volunteers, the scale with the lowest mean was general health (63), and that with the highest (89) was physical role. In the control population, the lowest mean was general health (73) and the highest (94.6) was physical function. A comparison of the health scales of both groups showed significant differences in physical function, physical role, body pain, general health and vitality. CONCLUSIONS: Based on the psychometric evaluation, the SF-36 shows satisfactory consistency with its supposed validity and reliability, although the translation of certain items will be further analyzed for subsequent modifications.

Assessment of primary health care access status: an analytic technique for decision making.

Access to health care is an issue that has caught the attention of health care providers, policy formulators, and policy analysts, with particular emphasis on access to primary care, which affords all people a viable portal into the health care system. This paper proposes an analytical approach to the assessment of relative primary care access status, measured as the capability to deliver basic primary care services within specific geographic civil areas, or parishes, within the state of Louisiana. An additive multiattribute utility method is employed to develop a scoring system to rank parishes according to a primary care access, or health system capability, numerical score. Routinely collected parameters are used to measure each parish's current capability to provide primary care services. These parameters include demographic, mortality, morbidity, and resource data. A group of experts was used to give weight to each parish's parameter values, resulting in a relative score for each. Thus, parishes (or other geographic areas) can be ranked according to their primary care access status. This information can then be used to allocate resources, to distribute funds for health care services, and to guide policy formulation and implementation.

Managerial epidemiology in the health administration curriculum.

With the rapid changes in health care delivery systems an appreciation and specialized understanding of epidemiology is a necessary requirement for health care administration practitioners. Managed care compels health care managers to focus on delivering health care services to populations and not individuals. The health care administrator today must focus on population-based management, and no longer can afford to ignore epidemiologic measurements. This article presents the development and implementation of a specialized course in managerial epidemiology. The specific phases of course development, course content, and course framework are presented and discussed.

Alteraciones psicologicas en ninos expuestos a ambientes domesticos ricos en plomo / Psychological changes in children exposed to a lead-rich home environments

Ya en trabajos anteriores los autores habian advertido que ninos de familias productoras de ceramica en el pueblo de Tonala, Mexico, tienden a presentar concentraciones sanguineas de plomo mas elevadas que los ninos de esa misma poblacion cuyos padres tienen otras ocupaciones. El objetivo del estudio que se presenta aqui fue determinar, por medio de las pruebas de inteligencia Wechsler y Bender-Gestalt, si un grupo de ninos de este pueblo con concentraciones elevadas de plomo en sangre (mayores de 40 microgramo/dl) evidenciaban anormalidades psicologicas, en comparacion con otro grupo cuyas concentraciones sanguineas eran relativamente bajas.Os resultados indican que el grupo con alta concentracion de plomo tuvo coeficiente medios verbal de rendimiento y total mas bajos que el grupo testigo y tambien que el deficit medio entre la edad mental y la cronologica fue mayor en este grupo. Ademas del saturnismo, sin duda intervinieron en el desarrollo de las anormalidades observadas factores socioeconomicos. No obstante, la comparacion de los resultados de las pruebas en ambos grupos es al parecer demostrativa de que los ninos en el grupo con concentraciones elevadas de plomo tienden a presentar un desarrollo mental retardado