Assessment of experimental observables for local extinction through unsteady laminar flame calculations

© 2019 The Combustion Institute Unsteady premixed and non-premixed counterflow laminar flame simulations were conducted in order to investigate extinction effects on observables commonly used in turbulent combustion. CH4 and n-C12H26 were the fuels studied, with air as the oxidizer at pressures of 1, 5, and 10 bar. It was determined that CH2O persists, compared to all other reactive species, during the extinction transient for both fuels and at all conditions, as the loss of OH concentration removes the dominant CH2O consumption pathway. The persistence of CH2O concentration is duplicated similarly in CH4 and n-C12H26 premixed flames. For non-premixed flames, the results indicate that the peak CH2O concentration reduction for n-C12H26 flames is milder compared to CH4 flames. Increasing the pressure causes an extension of reactivity, resulting in greater CH2O production and thus a delayed decay during the extinction transient. In addition, a change in the magnitude of the applied scalar dissipation rate for the non-premixed flames did not alter the trends of CH2O during extinction. Thus, caution is suggested when using CH2O in turbulent combustion experiments as a marker of the preheat zone thickness, given that increased levels of CH2O could be a result of multiple local extinction events. In addition, the product of OH and CH2O was found to scale well with the heat release rate for CH4 and n-C12H26 flames at multiple pressures. Finally, the CH* and OH* chemiluminescence was examined. CH* was found to extinguish slightly before the other species and more importantly, that once its concentration is reduced to a negligible level, the flame is on its way to extinction with no chance of recovery. OH* was determined to scale well with heat release at both 1 and 10 bar for both fuels and type of flames

The reproductive characteristics of mudskipper Periophthalmus barbarus (linnaeus 1760) (teleostei, Gobiidae) in the estuarine swamps of the Imo river, Nigeria

Between December 2007 and September 2008, aspects of the reproductive characteristics of the mudskipper Periophtalmus barbarus were studied using samples (n = 1802) obtained from the Imo River estuary. The overall sex ratio was not different from unity but analysis of ontogenic variation showed that males dominated in 5, 8, 10 and 11 cm total length size classes, while females were preponderant in the 6, 7 and 9 cm total length size class. The number of males was not higher than the number of females during the dry and wet seasons. The smallest mudskipper with incipient gonad was 8.0 cm total length. The median size at maturity was 8.9 cm total length. From the patterns of monthly variation in mean gonado-somatic index (GSI), it was concluded that the species breeds yearround, with at least, one major peak (August to December) and one minor peak (May) in a year. Length-weight allometric relationship for pooled data was W = 17.8 L2.60 with a dry season b value of 2.64 and a wet season b value of 2.55. The monthly variation in mean hepatosomatic index (HSI) showed that the pattern of variation in mean HSI was a reverse of that of the mean GSI. The implication of this is that the species draws down on the energy reserves in the liver for the recrudescence of the gonad. A trade-off was apparent in the body’s use of resources for gonadalrecrudescence. Consequently when the mean hepatosomanic index was low, mean gonad somatic index was high. A major peak of GSI occurred from August to December while a minor peak occurred in May

The role of the UPS in cystic fibrosis

CF is an inherited autosomal recessive disease whose lethality arises from malfunction of CFTR, a single chloride (Cl-) ion channel protein. CF patients harbor mutations in the CFTR gene that lead to misfolding of the resulting CFTR protein, rendering it inactive and mislocalized. Hundreds of CF-related mutations have been identified, many of which abrogate CFTR folding in the endoplasmic reticulum (ER). More than 70% of patients harbor the ΔF508 CFTR mutation that causes misfolding of the CFTR proteins. Consequently, mutant CFTR is unable to reach the apical plasma membrane of epithelial cells that line the lungs and gut, and is instead targeted for degradation by the UPS. Proteins located in both the cytoplasm and ER membrane are believed to identify misfolded CFTR for UPS-mediated degradation. The aberrantly folded CFTR protein then undergoes polyubiquitylation, carried out by an E1-E2-E3 ubiquitin ligase system, leading to degradation by the 26S proteasome. This ubiquitin-dependent loss of misfolded CFTR protein can be inhibited by the application of ‘corrector’ drugs that aid CFTR folding, shielding it from the UPS machinery. Corrector molecules elevate cellular CFTR protein levels by protecting the protein from degradation and aiding folding, promoting its maturation and localization to the apical plasma membrane. Combinatory application of corrector drugs with activator molecules that enhance CFTR Cl- ion channel activity offers significant potential for treatment of CF patients

The Impact of United Kingdom and Malaysia's Inherent Health Systems on Their COVID‐19 Responses: A Comparison of Containment Strategies

In March 2020, the outbreak of COVID‐19 was officially declared a global pandemic by the World Health Organization. Given the novelty of the virus, and hence, lack of official guidance on effective containment strategies, individual countries opted for different containment approaches ranging from herd immunity to strict lockdown. The opposing strategies followed by the United Kingdom and its former colony, Malaysia, stand exemplary for this. Real‐time polymerase chain reaction was implemented for testing in both counties. Malaysia acted with strict quarantining rules and infection surveillance. The United Kingdom followed an initially lenient, herd‐immunity approach with strict lockdown only enforced weeks later. Although based on the same health‐care structure historically, Malaysia developed a more unified health system compared with the United Kingdom. We suggest that this more centralized structure could be one possible explanation for why Malaysia was able to react in a more timely and efficient manner, despite its closer geographic proximity to China. We further explore how the differences in testing and quarantining strategy, as well as political situation and societal compliance could account for the discrepancy in the United Kingdom's versus Malaysia's relative success of COVID‐19 containment

The European Federation of Organisations for Medical Physics Policy Statement No. 6.1: Recommended Guidelines on National Registration Schemes for Medical Physicists

This EFOMP Policy Statement is an update of Policy Statement No. 6 first published in 1994. The present version takes into account the European Union Parliament and Council Directive 2013/55/EU that amends Directive 2005/36/EU on the recognition of professional qualifications and the European Union Council Directive 2013/59/EURATOM laying down the basic safety standards for protection against the dangers arising from exposure to ionising radiation. The European Commission Radiation Protection Report No. 174, Guidelines on Medical Physics Expert and the EFOMP Policy Statement No. 12.1, Recommendations on Medical Physics Education and Training in Europe 2014, are also taken into consideration. The EFOMP National Member Organisations are encouraged to update their Medical Physics registration schemes where these exist or to develop registration schemes taking into account the present version of this EFOMP Policy Statement (Policy Statement No. 6.1"Recommended Guidelines on National Registration Schemes for Medical Physicists")

Focusing on surgical and laser advances in glaucoma management

Introduction: Lowering the IOP remains the mainstay treatment to stop the progression of glaucoma. Different modalities can be used to achieve this including IOP lowering medications, laser, and surgeries. Nowadays, minimally invasive glaucoma surgeries and newer lasers are becoming more popular due to their safety profile, and their efficacy, allowing the patients to be less dependent on life long medications and substituting more invasive procedures as trabeculectomy, and shunt operations. / Areas covered: This review will go through how lasers and surgery are used to lower the IOP, and the newest techniques, and modalities used to achieve this. / Expert opinion: the authors of this review believe that in five years’ time lasers and minimally invasive glaucoma procedures will replace eye drops and surgeries like trabeculectomy and shunt procedures

Weight Loss in Advanced Chronic Kidney Disease: Should We Consider Individualised, Qualitative, ad Libitum Diets? A Narrative Review and Case Study.

In advanced chronic kidney disease, obesity may bring a survival advantage, but many transplant centres demand weight loss before wait-listing for kidney graft. The case here described regards a 71-year-old man, with obesity-related glomerulopathy; referral data were: weight 110 kg, Body Mass Index (BMI) 37 kg/m2, serum creatinine (sCr) 5 mg/dL, estimated glomerular filtration rate (eGFR) 23 mL/min, blood urea nitrogen (BUN) 75 mg/dL, proteinuria 2.3 g/day. A moderately restricted, low-protein diet allowed reduction in BUN (45–55 mg/dL) and good metabolic and kidney function stability, with a weight increase of 6 kg. Therefore, he asked to be enrolled in a weight-loss program to be wait-listed (the two nearest transplant centres required a BMI below 30 or 35 kg/m2). Since previous low-calorie diets were not successful and he was against a surgical approach, we chose a qualitative, ad libitum coach-assisted diet, freely available in our unit. In the first phase, the diet is dissociated; he lost 16 kg in 2 months, without need for dialysis. In the second maintenance phase, in which foods are progressively combined, he lost 4 kg in 5 months, allowing wait-listing. Dialysis started one year later, and was followed by weight gain of about 5 kg. He resumed the maintenance diet, and his current body weight, 35 months after the start of the diet, is 94 kg, with a BMI of 31.7 kg/m2, without clinical or biochemical signs of malnutrition. This case suggests that our patients can benefit from the same options available to non-CKD (chronic kidney disease) individuals, provided that strict multidisciplinary surveillance is assured

Determining the Effects of Past Negative Experiences Involving Patient Care

As the cost of healthcare continues to raise, the need to address nurse attrition, which is a contributing factor, also rises. While there are various factors that influence nurses’ decision to leave or stay, job satisfaction and ethical climate are significant variables. This study examined the effects of negative previous work experiences on job satisfaction and ethical climate. The results showed previous work experiences moderated both job satisfaction and ethical climate. In addition, ethical climate mediated the effects of previous experiences on job satisfaction. The implications include identifying nurses who may have had negative experiences prior to their current employment and providing them with ongoing support

Preparation of exosomes for siRNA delivery to cancer cells

Extracellular vesicles, in particular exosomes, have recently gained interest as novel drug delivery vectors due to their biological origin, abundance, and intrinsic capability in intercellular delivery of various biomolecules. This work establishes an isolation protocol to achieve high yield and high purity of exosomes for siRNA delivery. Human Embryonic Kidney cells (HEK-293 cells) are cultured in bioreactor flasks and the culture supernatant (hereon referred to as conditioned medium) is harvested on a weekly basis to allow for enrichment of HEK-293 exosomes. The conditioned medium (CM) is pre-cleared of dead cells and cellular debris by differential centrifugation and is subjected to ultracentrifugation onto a sucrose cushion followed by a washing step, to collect the exosomes. Isolated HEK-293 exosomes are characterized for yield, morphology and exosomal marker expression by nanoparticle tracking analysis, protein quantification, electron microscopy and flow cytometry, respectively. Small interfering RNA (siRNA), fluorescently labeled with Atto655, is loaded into exosomes by electroporation and excess siRNA is removed by gel filtration. Cell uptake in PANC-1 cancer cells, after 24 h incubation at 37 °C, is confirmed by flow cytometry. HEK-293 exosomes are 107.0 ± 8.2 nm in diameter. The exosome yield and particle-to-protein ratio (P:P) ratio are 6.99 ± 0.22 × 1012 particle/mL and 8.3 ± 1.7 × 1010 particle/µg, respectively. The encapsulation efficiency of siRNA in exosomes is ~ 10-20%. Forty percent of the cells show positive signals for Atto655 at 24 h post-incubation. In conclusion, exosome isolation by ultracentrifugation onto sucrose cushion offers a combination of good yield and purity. siRNA could be successfully loaded into exosomes by electroporation and subsequently delivered into cancer cells in vitro. This protocol offers a standard procedure for developing siRNA-loaded exosomes for efficient delivery to cancer cells

Stress induced polarization of immune-neuroendocrine phenotypes in Gallus gallus

Immune-neuroendocrine phenotypes (INPs) stand for population subgroups differing in immune-neuroendocrine interactions. While mammalian INPs have been characterized thoroughly in rats and humans, avian INPs were only recently described in Coturnix coturnix (quail). To assess the scope of this biological phenomenon, herein we characterized INPs in Gallus gallus (a domestic hen strain submitted to a very long history of strong selective breeding pressure) and evaluated whether a social chronic stress challenge modulates the individuals’ interplay affecting the INP subsets and distribution. Evaluating plasmatic basal corticosterone, interferon-γ and interleukin-4 concentrations, innate/acquired leukocyte ratio, PHA-P skin-swelling and induced antibody responses, two opposite INP profiles were found: LEWIS-like (15% of the population) and FISCHER-like (16%) hens. After chronic stress, an increment of about 12% in each polarized INP frequency was found at expenses of a reduction in the number of birds with intermediate responses. Results show that polarized INPs are also a phenomenon occurring in hens. The observed inter-individual variation suggest that, even after a considerable selection process, the population is still well prepared to deal with a variety of immune-neuroendocrine challenges. Stress promoted disruptive effects, leading to a more balanced INPs distribution, which represents a new substrate for challenging situations.Fil: Nazar, Franco Nicolas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; ArgentinaFil: Estevez, Inma. Centro de Investigación. Neiker - Tecnalia; EspañaFil: Correa, Silvia Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; ArgentinaFil: Marin, Raul Hector. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; Argentin