The Influence of Chronic Inflammation on Peripheral Motor Nerve Conduction Following Spinal Cord Injury: A Randomized Clinical Trial.

Objective: To examine the potential influence of chronic inflammation on peripheral motor nerve function in vivo following spinal cord injury (SCI). Methods: This study was part of a randomized, parallel-group, controlled clinical trial. The study included 20 participants with varying levels and severities of SCI randomized (3:2) to either a treatment group, consisting of a 12-week anti-inflammatory diet program, or control group. Outcome measures were assessed at baseline, 1 month, and 3 months and consisted of measures of motor nerve conduction velocity (NCV) and amplitude as well as markers of inflammation as assessed by various pro- and anti-inflammatory cytokines. Results: Despite a significant reduction in inflammation in the treatment group, 2-way repeated measures analysis of variance (ANOVA) showed no significant Group × Time interaction for motor NCV (p = .77) or M-wave amplitude (p = .61). Further, the change in motor NCV and M-wave amplitude were not shown to be associated with the change in inflammatory mediators as assessed via a backwards elimination multiple regression analysis. Conclusion: These results suggest that at physiologically relevant concentrations, inflammatory mediators may not have a substantial influence on peripheral motor nerve conduction in vivo following SCI. Future studies may still be warranted to examine the potential for central effects.

Conversion of chemical scrubbers to biotrickling filters for VOCs and H2S treatment at low contact times.

The purpose of this work was to evaluate the technical and economical feasibility of converting three chemical scrubbers in series to biotrickling filters (BTFs) for the simultaneous removal of H2S and volatile organic compounds (VOCs). The conversion of the full-scale scrubbers was based on previous conversion protocols. Conversion mainly required replacing the original carrier material and recycle pumps as well as modifying the controls and operation of the reactors. Complete removal of H2S and VOCs on a routine basis was reached at neutral pH in a longer period of time compared to previous conversions reported. Biotrickling filters operated at a gas contact time of about 1.4 s per reactor and at pH controlled between 6.5 and 6.8. Inlet average concentrations below 10 ppmv of H2S and below 5 ppmv for VOCs were often completely removed. The first and second bioreactors played a primary role in H2S removal. Year-round operation of the biotrickling filters proved the ability of the system to handle progressive load increases of H2S and VOCs. However, fast, sudden load changes often lead to reduced removal efficiencies. Odor analyses showed average removal efficiencies above 80%. Gas chromatography-mass spectrometry of selected samples showed that outlet odor concentration was due to limited removal of VOCs. The conversion showed was economically viable taking into account the theoretical consumption of chemicals needed for the absorption and oxidation of both H2S and VOCs.

Inventory and treatment of compost maturation emissions in a municipal solid waste treatment facility.

Emissions of volatile organic compounds (VOCs) from the compost maturation building in a municipal solid waste treatment facility were inventoried by solid phase microextraction and gas chromatography-mass spectrometry. A large diversity of chemical classes and compounds were found. The highest concentrations were found for n-butanol, methyl ethyl ketone and limonene (ppmv level). Also, a range of compounds exceeded their odor threshold evidencing that treatment was needed. Performance of a chemical scrubber followed by two parallel biofilters packed with an advanced packing material and treating an average airflow of 99,300 m(3) h(-1) was assessed in the treatment of the VOCs inventoried. Performance of the odor abatement system was evaluated in terms of removal efficiency by comparing inlet and outlet abundances. Outlet concentrations of selected VOCs permitted to identify critical odorants emitted to the atmosphere. In particular, limonene was found as the most critical VOC in the present study. Only six compounds from the odorant group were removed with efficiencies higher than 90%. Low removal efficiencies were found for most of the compounds present in the emission showing a significant relation with their chemical properties (functionality and solubility) and operational parameters (temperature, pH and inlet concentration). Interestingly, benzaldehyde and benzyl alcohol were found to be produced in the treatment system.

Environmental assessment of different biofilters for the treatment of gaseous streams.

Biological techniques have been considered as an interesting alternative to treat gaseous streams from industrial processes. In this work, the performance of biofilters was evaluated from an environmental point of view by using Life Cycle Assessment methodology. More specifically, the potential impacts of four biofilters packed with different organic materials: spherical clay pellets covered with compost, a mixture of coconut fibre and sludge based carbon, peat and heather and pine bark have been quantified. The impact categories considered in this work were: eutrophication, acidification, global warming, photochemical oxidation, malodorous air, human toxicity and marine, terrestrial and freshwater ecotoxicity. From an environmental point of view, the reactor packed with coconut fibre and sludge based carbon appears to be the most suitable alternative since it presented the lowest values in almost all the impact categories assessed. On the other hand, the biofilter packed with clay pellets covered with compost seems to be the most penalized bioreactor providing the highest impacts for six of the nine impact categories evaluated, mainly due to the significant pressure drop achieved in the reactor which led to a considerable increase of energy demand. The reactor packed with coconut fibre and sludge based carbon is also the most beneficial alternative after performing the normalization step. In this case, the alternatives of peat and heather and pine bark are the less favourable ones in terms of photochemical oxidation, which was attributed to the lowest efficiency of methyl isobutyl ketone removal efficiency observed in both configurations. On the other hand, the option of treating off-gases is, in general, more positive and advisable than the direct discharge to the atmosphere.

El ser médico: una perspectiva cimentada en un enfoque holístico / Being physician: a perspective based on a holistic approach

Introducción: la concepción sociocultural de cada oficio, es susceptible de modificarse con el transcurrir del tiempo. Es problemático recurrir totalmente al juramento hipocrático en tiempos contemporáneos pragmáticos donde se ha incursionado como intermediarios del mercado de la salud. La actualización científica debe realizarse conjuntamente con premisas bioéticas y conciencia sobre la actualidad de la práctica médica. Objetivo: persuadir al médico colombiano a reconocer en una era compleja, lograr prácticas en un enfoque holístico. Desarrollo: se deberá hacer a la idea en todo su ser profesional, de la inmediatez de su trabajo dejando atrás la obviedad por la que el interés económico sacrificó la equidad y la solidaridad. El médico debe laborar dentro de las discutibles ventajas del sistema y ejercer su profesionalismo al máximo; siendo recursivo sin sacrificar sus principios y del ejercicio médico en pro de controlar la enfermedad del paciente. Es vital la actualización y comprensión de preceptos bioéticos como el principio de la razón suficiente, la navaja de Occam, y el razonamiento abductivo. Conclusiones: es necesario que se reconozca en su ser profesional, contextualizándose en tiempo y lugar; donde se involucre en profesión y vocación de forma holística con los requerimientos del sistema, de sus responsabilidades y necesidades del paciente, a través de un pensamiento diagnóstico abductivo, humano y filosófico.

Introduction: the cultural conception of professions, are likely changing with the passage of time and their idiosyncrasy. It is problematic to rely blindly the Hippocratic oath in the contemporary age, where, both physicicans and patients have become intermediaries of the healthcare market. The scientific update must be performed in conjunction with specific bioethical premises with a deep awareness on current medical practice. Objective: to persuade Colombian physicians, as philosophical being, to recognize this age requires him or her to be a physician whose practice follow a holistic approach. Development: the Colombian clinician should get an idea of the professional context full of immediacy, which leave behind the obvious reason because the economic interest sacrificed equity and solidarity. Physicians have to work within the questionable benefits of the system and exercise maximum professionalism, being resourceful without sacrificing their bioethical principles and medical correct practice in favor of controlling the patient’s illness. For this, it is vitally important to update and understand bioethical precepts like the principle of sufficient reason, Occam’s razor, and abductive reasoning. Conclusions: it is necessary that Colombian physicians, acknowledged and engage within the profession and vocation in a holistic way taking into account the requirements of the system, the patient’s needs and their own commitment to this through abductive, human and philosophical diagnosis thought.

Cost and effluent quality controllers design based on the relative gain array for a nutrient removal WWTP.

The main objective of this work was the design of different effluent quality controllers and a cost controller for WWTPs. This study was based on the relative gain array (RGA) analysis applied to an anaerobic/anoxic/aerobic (A(2)/O) configuration of a simulated WWTP, with combined removal of organic matter, nitrogen and phosphorus. The RGA analysis was able to point out the best pairing amongst the input and the output control variables of the plant to design low order and decentralized effluent quality controllers, such as proportional-integral controllers for each variable of interest (ammonium, nitrate and phosphate). In a second step, a cost controller to automatically search for the most economic setpoints of the effluent quality controllers was implemented based on the best decentralized control structure tested. The simulated plant was operated under different control modes that chronologically represent control configurations becoming gradually more complex: (i) in open loop; (ii) with dissolved oxygen (DO) control in the last aerobic reactor only; (iii) with the effluent quality controllers active; (iv) with the effluent quality controllers active and automatically receiving the setpoints from a cost controller. The effluent quality controllers alone and the cost control together with effluent quality controllers could save up to 42,000 Euros/year and 225,000 Euros/year, respectively, when compared to the operating costs of the plant operating with DO control (a reduction of 2.5% and 13% of the operating costs, respectively). The cost controller proved to be a good tool for automating the search of the most profitable setpoints of the effluent quality controllers for a given cost setpoint.