•Jet impingement cooling for different Reynolds numbers, from 9,800 to 120,000.•Results of the dissipated heat, transverse heat flux, and rewetting and maximum cooling rate fronts.•Large-scale tests ...provide important data of the cooling, in particular far from the impact location.•Similar results for different jet nozzle diameters but with the same flow rate.•The higher the Reynolds number, the larger the heat dissipation far from the impact location.
Jet impingement cooling has been intensively studied in the past by many authors because of its important application in the metallurgical industry; however, most of the experiments in the literature are at laboratory scale and, in some cases, not near industrial conditions. In this study, we performed cooling experiments near industrial conditions in a new experimental apparatus with a large nickel plate as test sample, which was heated until 850 ∘C before being cooled by a single circular water jet. Five experimental results are presented with different jet Reynolds numbers, from 9,800 to 120,000, obtained by varying the water flow rate and the nozzle diameter. The presented results are: temperature evolutions during cooling, dissipated heat flux (estimated by solving a 2D inverse heat conduction problem), transverse heat flux at the heat-exchanging surface, and the characteristics (position and velocity) of the rewetting and maximum cooling rate fronts. The increase in the jet Reynolds number increased slightly the heat flux at the stagnation zone, but increased it substantially for positions farther from the impact location. The transverse heat flux increased with the passage of the rewetting front and then decreased, and its magnitude was practically the same regardless of the jet Reynolds number. The change in the nozzle diameter did not affect significantly the heat transfer nor the rewetting front growth, although the heat dissipation was slightly higher with the smaller nozzle, possibly because of the higher jet impact velocity. Finally, we compared the present results with some found in the literature in similar conditions, showing that laboratory experiments are valuable to provide detailed information, especially near the stagnation zone, but large-scale experiments allow obtaining macroscale data of the cooling process.
Cancer is a major public health problem, but despite the several treatment approaches available, patients develop resistance in short time periods, making overcoming resistance or finding more ...efficient treatments an imperative challenge. Silver nanoparticles (AgNPs) have been described as an alternative option due to their physicochemical properties. The scope of this review was to systematize the available scientific information concerning these characteristics in AgNPs synthesized according to green chemistry’s recommendations as well as their cytotoxicity in different cancer models. This is the first paper analyzing, correlating, and summarizing AgNPs’ main parameters that modulate their cellular effect, including size, shape, capping, and surface plasmon resonance profile, dose range, and exposure time. It highlights the strong dependence of AgNPs’ cytotoxic effects on their characteristics and tumor model, making evident the strong need of standardization and full characterization. AgNPs’ application in oncology research is a new, open, and promising field and needs additional studies.
We present an efficient computational methodology to obtain the viscoelastic response of dilute solutions of semiflexible filaments. By considering an approach based on the fluctuation-dissipation ...theorem, we were able to evaluate the dynamical properties of probe particles immersed in solutions of semiflexible filaments from relaxation simulations with a relatively low computational cost and higher precision in comparison to those based on stochastic dynamics. We used a microrheological approach to obtain the complex shear modulus and the complex viscosity of the solution through its compliance which was obtained directly from the dynamical properties of a probe particle attached to an effective medium described by a mesoscopic model,
i.e.
, an effective filament model (EFM). The relaxation simulations were applied to assess the effects of the bending energy on the viscoelasticity of the semiflexible filament solutions, and our methodology was validated by comparing the numerical results to the experimental data on DNA and collagen solutions.
We present an efficient computational methodology to obtain the viscoelastic response of dilute solutions of semiflexible filaments.
The aims of this study were 1) to characterize the intensity of the vibration stimulation in women diagnosed with fibromyalgia (FM) compared to a control group of healthy women (HW) matched by age ...and anthropometric parameters, and 2) to investigate the effect of a single session of whole body vibration (WBV) on inflammatory responses. Levels of adipokines, soluble tumor necrosis factor receptors (sTNFr1, sTNFr2), and brain-derived neurotrophic factor (BDNF) were determined by enzyme-linked immunosorbent assay. Oxygen consumption (VO2) was estimated by a portable gas analysis system, heart rate (HR) was measured using a HR monitor, and perceived exertion (RPE) was evaluated using the Borg scale of perceived exertion. Acutely mild WBV increased VO2 and HR similarly in both groups. There was an interaction (disease vs vibration) in RPE (P=0.0078), showing a higher RPE in FM compared to HW at rest, which further increased in FM after acute WBV, whereas it remained unchanged in HW. In addition, there was an interaction (disease vs vibration) in plasma levels of adiponectin (P=0.0001), sTNFR1 (P=0.000001), sTNFR2 (P=0.0052), leptin (P=0.0007), resistin (P=0.0166), and BDNF (P=0.0179). In conclusion, a single acute session of mild and short WBV can improve the inflammatory status in patients with FM, reaching values close to those of matched HW at their basal status. The neuroendocrine mechanism seems to be an exercise-induced modulation towards greater adaptation to stress response in these patients.
Escherichia coli are believed to be associated with postpartum metritis and endometritis but their role in the pathogenesis of both diseases is still undefined. In this study, uterine swabs for E. ...coli isolation were collected from 374 lactating Holstein cows housed on 4 commercial farms near Ithaca, New York. A total, 125 of 374 cows (33.4%) were positive for E. coli culture. Standard multiplex PCR protocols were used to screen the isolates for the presence of 32 virulence factor genes. Cows that had twin parturition were 4.4 times more likely to have intrauterine E. coli contamination than those that gave birth to single live female calves. Stillborn parturition and birth of single live male calves also increased the odds of intrauterine contamination by E. coli (3.7- and 1.6-fold, respectively) compared with birth of live female calves. Six virulence factors, common to extraintestinal and enteroaggregative E. coli, were found to be associated with metritis and endometritis: fimH, hlyA, cdt, kpsMII, ibeA, and astA. The virulence factor gene fimH was the most prevalent and the most significant: intrauterine E. coli carrying fimH and at least 1 of the other 5 identified virulence factors were pathogenic, and phylogenetic analysis based on the nucleotide sequence of DNA gyrase from 41 such IUEC revealed 2 clades.
The objective of this study was to evaluate whether pre-weaning heifer calves divergent for residual feed intake (RFI) or residual feed intake and body weight gain (RIG) exhibit differences in ...thermography, blood, and ruminal parameters. Thirty-two Gyr heifer calves were enrolled in a 63-d trial and classified into 2 feed efficiency (FE) groups based on RFI and RIG (mean #177; 0.5 SD). The groups were classified as high efficiency (HE) RFI (HE RFI, n = 9), HE RIG (HE RIG, n = 10), low efficiency (LE) RFI (LE RFI, n = 10), and LE RIG (LE RIG, n = 11). The amount of whole milk provided for each calf was calculated based on their metabolic weight at birth (42% x BW.sup.0.75). The liquid diet was divided into two meals at 0700 and 1400 h. The total solid diet (TSD) was composed of 92% concentrate and 8% of Tifton 85 hay chopped in 5-cm lengths, as fed. Intake was measured daily. Blood concentrations of insulin, beta hydroxybutyrate, urea, and glucose, and ruminal pH, N-NH.sub.3, and volatile fatty acids (VFA) were evaluated at 14, 28, 42, 56, and 70 days of age. Thermal images of the calves were taken with an infrared camera (FLIR T420, FLIR Systems Inc., Wilsonville, OR) on d 56 (#177;3) at 0600 h, before the morning feeding. Total VFA concentration and propionate as % of total VFA were 24.2% and 22.2% lower in HE RFI compared to LE RFI calves, respectively. On the other hand, acetate as % of total VFA was 10.6% greater in HE RFI than LE RFI calves. Blood urea concentration tended to be greater in LE RFI than HE RFI calves. High efficiency HE RIG tended to have 6.8% greater acetate and 15.4% lower propionate as % of total VFA than LE RIG. Blood insulin concentration was greater and blood glucose tended to be greater for LE RIG than HE RIG group. Low efficiency RIG group had greater left rib, left flank, and anus surface temperature measured by infrared thermography than the HE RIG group. Differences in ruminal fermentation do not seem to be associated with pre-weaning calves efficiency, while differences in protein metabolism seem to affect RFI during this phase. Infrared thermography appears to be correlated to RIG in pre-weaning heifer calves.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We characterized 15 Trypanosoma cruzi isolates from bats captured in the Amazon, Central and Southeast Brazilian regions. Phylogenetic relationships among T. cruzi lineages using SSU rDNA, cytochrome ...b, and Histone H2B genes positioned all Amazonian isolates into T. cruzi I (TCI). However, bat isolates from the other regions, which had been genotyped as T. cruzi II (TC II) by the traditional genotyping method based on mini-exon gene employed in this study, were not nested within any of the previously defined TCII sublineages, constituting a new genotype designated as TCbat. Phylogenetic analyses demonstrated that TCbat indeed belongs to T. cruzi and not to other closely related bat trypanosomes of the subgenus Schizotrypanum, and that although separated by large genetic distances TCbat is closest to lineage TCI. A genotyping method targeting ITS1 rDNA distinguished TCbat from established T. cruzi lineages, and from other Schizotrypanum species. In experimentally infected mice, TCbat lacked virulence and yielded low parasitaemias. Isolates of TCbat presented distinctive morphological features and behaviour in triatomines. To date, TCbat genotype was found only in bats from anthropic environments of Central and Southeast Brazil. Our findings indicate that the complexity of T. cruzi is larger than currently known, and confirmed bats as important reservoirs and potential source of T. cruzi infections to humans.
Rhamnolipids (RMLs) have more effectiveness for specific uses according to their homologue proportions. Thus, the novelty of this work was to compare mono‐RMLs and di‐RMLs physicochemical properties ...on microbial enhanced oil recovery (MEOR) applications. For this, RML produced by three strains of Pseudomonas aeruginosa containing different homologues proportion were used: a mainly mono‐RMLs producer (mono‐RMLs); a mainly di‐RMLs producer (di‐RMLs), and the other one that produces relatively balanced amounts of mono‐RML and di‐RML homologues (mono/di‐RML). For mono‐RML, the most abundant molecules were Rha‐C10C10 (m/z 503.3), for di‐RML were RhaRha‐C10C10 (m/z 649.4) and for Mono/di‐RML were Rha‐C10C10 (m/z 503.3) and RhaRha‐C10C10 (m/z 649.4). All RMLs types presented robustness under high temperature and variation of salinity and pH, and high ability for oil displacement, foam stability, wettability reversal and were classified as safe for environment according to the European Union Directive No. 67/548/EEC. For all these properties, it was observed a highlight for mono‐RML. Mono‐RML presented the lowest surface tension (26.40 mN/m), interfacial tension (1.14 mN/m), and critical micellar concentration (CMC 27.04 mg/L), the highest emulsification index (EI24 100%) and the best wettability reversal (100% with 25 ppm). In addition, mono‐RML showed the best acute toxicity value (454 mg/L), making its application potential even more attractive. Based on the results, it was concluded that all RMLs homologues studied have potential for MEOR applications. However, results showed that mono‐RML stood out and have the best mechanism of oil incorporation in micelles due their most effective surface‐active physicochemical features.
The objective of this study was to evaluate the effect of a standardized botanical extract of Croton lechleri, named crofelemer extract, on fecal dry matter and fecal scores on diarrheic newborn ...Holstein bull calves induced by enterotoxigenic Escherichia coli. A double-blinded randomized clinical trial was performed in which 60 newborn Holstein bull calves were clean caught and transported to an isolation facility where calves were individually housed and randomly assigned to 1 of 3 treatment groups: placebo (control), enteric-coated formulation of crofelemer extract (ECROF), and nonenteric-coated formulation of crofelemer extract (CROF). Diarrhea was induced at first feeding with an inoculum of the enterotoxigenic Escherichia coli (ATCC 31616) administered with a third of the recommended dose of a colostrum replacer. All calves enrolled in this study received treatments starting on the second feeding (diarrhea onset) and treatments were administered before feeding time (0600 and 1600h) for 6 feedings consecutively. All calves in this study had failure of passive transfer. The only cause of death in this study was due to septicemia, accounting for 1 death out of each treatment group. All the calves were examined twice daily, within 2h after feeding, from d 1 (prechallenge) until 10, on d 15, and a last examination on d 25 of life. Five parameters were evaluated during each examination; rectal temperature, clinical assessment of dehydration status, fecal scores, attitude, and appetite. No differences were observed between treatment groups for rectal temperature, attitude, and appetite. Fecal dry matter was analyzed as prechallenge fecal dry matter, dry matter during treatment, and fecal dry matter after treatment cessation. No difference in prechallenge fecal dry matter was observed and prechallenge fecal dry matter was used as a covariate in the models. Fecal dry matter during treatment was significantly higher for ECROF calves when compared with control calves and CROF calves. Additionally, ECROF fecal dry matter after treatment cessation had a statistical tendency to be higher when compared with control calves. Together, these results suggest that enteric-coated formulation of the standardized crofelemer extract, a natural-product with antisecretory properties, can significantly increase fecal dry matter of neonatal calves with experimentally induced enterotoxigenic Escherichia coli diarrhea. More research is needed to test the efficacy of enteric-coated crofelemer on incidence and severity of secretory diarrhea on calves under natural challenge conditions.
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