Performance analysis of a mono-cylinder diesel engine using soy straight vegetable oil as fuel with varying temperature and injection angle

Experimental results are presented for a compression ignition engine with one cylinder refrigerated by air, fueled with soy straight vegetable oil (SVO), filtered at 500 nm and blended with diesel at volume percentages of 10, 30, 50, 70 and 100%. Performance tests varying the injection angle and the fuel temperature were conducted. The results show an increase in torque and power compared to pure diesel, especially with the SVO50 and SVO70 mixtures. However, there was an increase in the specific consumption, although engine efficiency was only slightly lower due to the lower heating value of oil. The use of SVO as fuel is feasible, but durability tests must be performed, mainly to discover potential maintenance problems.     

Hydrogen production by Escherichia coli ΔhycA ΔlacI using cheese whey as substrate

This study reports a fermentative hydrogen production by Escherichia coli using cheese whey as substrate. To improve the biohydrogen production, an E. coli ΔhycA ΔlacI strain (WDHL) was constructed. The absence of hycA and lacI genes had a positive effect on the biohydrogen production. The strain produced 22% more biohydrogen in a shorter time than the wild-type (WT) strain. A Box-Behnken experimental design was used to optimize pH, temperature and substrate concentration. The optimal initial conditions for biohydrogen production by WDHL strain were pH 7.5, 37 °C and 20 g/L of cheese whey. The specific production rate was improved from 3.29 mL H₂/optical density at 600 nm (OD_600nm) unit-h produced by WDHL under non-optimal conditions to 5.88 mL H₂/OD_600nm unit-h under optimal conditions. Using optimal initial conditions, galactose can be metabolized by WDHL strain. The maximum yield obtained was 2.74 mol H₂/mol lactose consumed, which is comparable with the yield reached in other hydrogen production processes with Clostridium sp. or mixed cultures.     

Residence Time Distribution of a Capillary Microreactor Used for Pharmaceutical Synthesis

The main drivers for application of small-scale reactors in the pharmaceutical industry are the possibility of rapid synthesis and screening of novel drugs as well as the readiness of the scale-up. The characterization of fluid flow pattern was performed through step-up and step-down residence time distribution experiments using a tracer at six different flow rates. Four single-parameter models were considered for representing deviations from ideal plug flow and ideal laminar flow in tubes. The model that provided the best results was the axial dispersion model and the Peclet and Reynolds numbers could be well correlated. Obtained Peclet values from 44 to 244 were close to Pe > 100, in which axial dispersion can be neglected and the reactor can be considered as plug flow reactor.     

Bidirectional connectivity via fish ladders in a large Neotropical river: Response to a comment

In a recent article, we described fitting electronic tags to the fish Prochilodus lineatus to document how a fishway connected aquatic habitats downstream and upstream of a major dam. Moreover, given that tagged fish remained upstream or downstream for periods extending months and years before returning to the fishway, and that observed patterns of passage were consistent with seasonal migratory cycles, and building on existing literature, we speculated that the fishway allows fish access to spawning habitats upstream and feeding habitats downstream. Our interpretation of the movement data resulted in several comments from Pelicice, Pompeu, and Agostinho (2020) and they outline various reasons by which, in their opinion, some of our conclusions may be mistaken. Their critique is threefold. First, they argue that the percentage of fish attracted into the fishway is too low to consider the fishway an effective link between the reservoir and the river downstream. We contend that without estimates of population size it is impossible to judge if 28% passage is “limited”; conceivably, the absolute number of fish passed may still be enough to maintain a viable population. Second, they assert that because receivers were located only in the fishway it is unknown if fish that used the fishway remained near the dam, or if they continued their migration. We counter with a brief literature review that documents P. lineatus migrating through reservoirs and spawning in tributaries. Third, they advocate for a broader conservation perspective and for additional research. We agree and, in the article, had already expressed this view that fishways are only a temporary fix and that we support their use only as an element of a broader environmental management package. We also agree with the need for more research but argue that procrastinating on conservation action may not be wise because we do not know if the research will be done, how long it will take, or what the cost may be of waiting.     

High concentrations of waste anesthetic gases induce genetic damage and inflammation in physicians exposed for three years: A cross-sectional study

This cross-sectional study analyzed the impact of occupational waste anesthetic gases on genetic material, oxidative stress, and inflammation status in young physicians exposed to inhalational anesthetics at the end of their medical residency. Concentrations of waste anesthetic gases were measured in the operating rooms to assess anesthetic pollution. The exposed group comprised individuals occupationally exposed to inhalational anesthetics, while the control group comprised individuals without anesthetic exposure. We quantified DNA damage; genetic instability (micronucleus-MN); protein, lipid, and DNA oxidation; antioxidant activities; and proinflammatory cytokine levels. Trace concentrations of anesthetics (isoflurane: 5.3 ± 2.5 ppm, sevoflurane: 9.7 ± 5.9 ppm, and nitrous oxide: 180 ± 150 ppm) were above international recommended thresholds. Basal DNA damage and IL-17A were significantly higher in the exposed group [27 ± 20 a.u. and 20.7(19.1;31.8) pg/mL, respectively] compared to the control group [17 ± 11 a.u. and 19.0(18.9;19.5) pg/mL, respectively], and MN frequency was slightly increased in the exposed physicians (2.3-fold). No significant difference was observed regarding oxidative stress biomarkers. The findings highlight the genetic and inflammatory risks in young physicians exposed to inhalational agents in operating rooms lacking adequate scavenging systems. This potential health hazard can accompany these subjects throughout their professional lives and reinforces the need to reduce ambient air pollution and consequently, occupational exposure.     

Moderate,but Not Excessive,Training Attenuates Autophagy Machinery in Metabolic Tissues

The protective effects of chronic moderate exercise-mediated autophagy include the prevention and treatment of several diseases and the extension of lifespan. In addition, physical exercise may impair cellular structures, requiring the action of the autophagy mechanism for clearance and renovation of damaged cellular components. For the first time, we investigated the adaptations on basal autophagy flux in vivo in mice’s liver, heart, and skeletal muscle tissues submitted to four different chronic exercise models: endurance, resistance, concurrent, and overtraining. Measuring the autophagy flux in vivo is crucial to access the functionality of the autophagy pathway since changes in this pathway can occur in more than five steps. Moreover, the responses of metabolic, performance, and functional parameters, as well as genes and proteins related to the autophagy pathway, were addressed. In summary, the regular exercise models exhibited normal/enhanced adaptations with reduced autophagy-related proteins in all tissues. On the other hand, the overtrained group presented higher expression of Sqstm1 and Bnip3 with negative morphological and physical performance adaptations for the liver and heart, respectively. The groups showed different adaptions in autophagy flux in skeletal muscle, suggesting the activation or inhibition of basal autophagy may not always be related to improvement or impairment of performance.