Particle-in-cell (PIC) methods have a long history in the study of laser-plasma interactions. Early electromagnetic codes used the Yee staggered grid for field variables combined with a leapfrog ...EM-field update and the Boris algorithm for particle pushing. The general properties of such schemes are well documented. Modern PIC codes tend to add to these high-order shape functions for particles, Poisson preserving field updates, collisions, ionisation, a hybrid scheme for solid density and high-field QED effects. In addition to these physics packages, the increase in computing power now allows simulations with real mass ratios, full 3D dynamics and multi-speckle interaction. This paper presents a review of the core algorithms used in current laser-plasma specific PIC codes. Also reported are estimates of self-heating rates, convergence of collisional routines and test of ionisation models which are not readily available elsewhere. Having reviewed the status of PIC algorithms we present a summary of recent applications of such codes in laser-plasma physics, concentrating on SRS, short-pulse laser-solid interactions, fast-electron transport, and QED effects.
Background. Infants with pertussis infection are at risk of severe clinical illness and death. Several countries, including the United Kingdom, have introduced maternal pertussis vaccination during ...pregnancy to protect infants from infection following national increases in pertussis notifications. The objective of this study was to estimate the effectiveness of maternal pertussis vaccination in protecting infants against laboratory-confirmed pertussis infection. Methods. A case-control study was undertaken in England and Wales between October 2012 and July 2013. Cases were infants aged <8 weeks at onset with pertussis infection tested by real-time polymerase chain reaction or culture. Family doctors of each case were asked to identify healthy infants born consecutively after the case in each practice, to act as controls. Fifty-eight cases and 55 controls were included in this study. Odds ratios (ORs) were calculated for the association between maternal vaccination and infant pertussis infection. The vaccine effectiveness (VE) was calculated as 1 – OR. This was adjusted for sex, geographical region, and birth period. Results. Mothers of 10 cases (17%) and 39 controls (71%) received pertussis vaccine in pregnancy. This gave an unadjusted VE of 91% (95% confidence interval CI, 77%–97%). Adjusted VE was 93% (95% CI, 81%–97%). Conclusions. Maternal pertussis vaccination is effective in preventing pertussis infection in infants aged <8 weeks and may be considered in other countries experiencing high levels of pertussis notifications.
Zebrafish,
Danio rerio, are frequently handled during husbandry and experimental procedures in the laboratory, yet little is known about the physiological responses to such stressors. We measured the ...whole-body cortisol levels of adult zebrafish subjected to net stress and air exposure at intervals over a 24
h period; cortisol recovered to near control levels by about 1
h post-net-stress (PNS). We then measured cortisol at frequent intervals over a 1
h period. Cortisol levels were more than 2-fold higher in net stressed fish at 3
min PNS and continued to increase peaking at 15
min PNS, when cortisol levels were 6-fold greater than the control cortisol. Mean cortisol declined from 15 to 60
min PNS, and at 60
min, net-stressed cortisol was similar to control cortisol. Because the age of fish differed between studies, we examined resting cortisol levels of fish of different ages (3, 7, 13, and 19
months). The resting cortisol values among tanks with the same age fish differed significantly but there was no clear effect of age. Our study is the first to report the response and recovery of cortisol after net handling for laboratory-reared zebrafish.
Background Studies on long-term outcomes of the arterial switch operation (ASO) for transposition of the great arteries (TGA) are uncommon. Thus, we sought to determine the long-term outcomes for ...patients after ASO performed at a single institution over a 25-year period. Methods From 1983 to 2009, 618 patients underwent the ASO for TGA and were reviewed retrospectively. Results Overall early mortality was 2.8%. Risk factors for early death on multivariate analysis were resection of left ventricular outflow tract obstruction at time of ASO ( p = 0.001), weight less than 2.5 kg at time of ASO ( p < 0.001), associated aortic arch obstruction ( p = 0.043), and the need for postoperative extracorporeal membrane oxygenation ( p < 0.001). Mean follow-up time was 10.6 years (range 2 months to 26.1 years). Late mortality was 0.9%. Reintervention was significantly higher ( p < 0.001) in patients with ventricular septal defect or arch obstruction versus those without them (25.2% and 23.4% vs 5.9% at 15- year follow-up). Risk factors for late reintervention were left ventricular outflow tract obstruction at time of ASO ( p < 0.001) and a greater circulatory arrest time ( p < 0.001). Freedom from at least moderate neoaortic valve regurgitation for the entire cohort was 98.7% (95% confidence interval 96.8 to 99.5%) at 20 years. Mild neoaortic regurgitation was seen in 25.6% of patients at mean follow-up. All patients were free of arrhythmia and heart failure symptoms at last follow-up. Conclusions The ASO can be performed with good long-term results. Patients with associated ventricular septal defect and aortic arch obstruction warrant close follow-up.
Plasma cortisol levels have been used to evaluate the stress response in a variety of cultured fish species. However, little is known about the stress response of zebrafish,
Danio rerio, despite its ...extensive use as a laboratory research organism. Due to its small size, evaluation of whole-body cortisol has provided a means to assess zebrafish stress levels Understanding the role of crowding on zebrafish whole-body cortisol would allow researchers to optimize various rearing procedures. The aim of this study was to determine the zebrafish whole-body cortisol response to crowding stress. Baseline cortisol values have not been established for zebrafish; therefore, we compared specific treatment groups acclimated to similar conditions. We crowded zebrafish at a high density (40 fish/L) for 3 h (acute stress), or 5 days (chronic stress). Crowding resulted in a four-fold increase in mean whole-body cortisol level in both groups compared to zebrafish maintained at a much lower density (0.25 fish/L). Additional experiments demonstrated that the cortisol response to crowding was modulated by fasting, feeding and density. In large glass aquaria (76 L), fasted, crowded fish (40 fish/L) had significantly higher cortisol compared to fasted, control fish (0.2 fish/L). Furthermore, weight was inversely related to cortisol level in fasted, crowded fish held in large glass aquaria. For fed fish, crowding did not significantly increase cortisol level, suggesting an interaction between feeding and crowding. In small tanks (4 L), crowding (40 fish/L) did not significantly increase cortisol compared to control fish held at 4 fish/L. Our results suggest that whole-body cortisol is a useful indicator of crowding stress in fasted, adult zebrafish. Understanding how crowding and other environmental conditions affect zebrafish fitness could aid in optimizing zebrafish growth, health and reproduction as well as improving the consistency and reproducibility of in vivo studies that use this popular vertebrate model.
Preeclampsia is pregnancy-specific, affecting 2% to 7% of women, and is a leading cause of perinatal and maternal morbidity and mortality. Preeclampsia may also predispose the fetus to increased ...risks of adult cardiovascular disease. Selenium, acting through the selenoprotein glutathione peroxidases, has critical roles in regulating antioxidant status. Recent reports implicate poor maternal selenium status as a nutritional factor predisposing the mother to preeclampsia but the fetus and placenta have not been studied in tandem. Measurement of selenium concentrations, expression, and activity levels of glutathione peroxidase and markers of oxidative stress were performed on maternal and umbilical venous blood samples or the placenta from 27 normal pregnant, 25 preeclamptic, and 22 healthy age-matched nonpregnant women. The results of this study revealed highly significant reductions in serum selenium concentrations and plasma glutathione peroxidase activity in pregnancy per se compared to nonpregnant controls. Moreover, these levels were further decreased in the preeclamptic mothers and babies compared to normal pregnancies. Umbilical venous selenium was particularly low (42.1±11.8 and 29.0±9.9 μg/L; mean±SD; P<0.05). Both mother and baby had significantly increased levels of markers for oxidative stress in the preeclamptic group. The placental glutathione peroxidase activity and immunohistochemical staining were also reduced in the preeclampsia placentae. Oxidative stress associated with preeclampsia may be a consequence of reduced antioxidant defense pathways specifically involving glutathione peroxidases, perhaps linked to reduced selenium availability. Reduced glutathione peroxidases could be associated with increased generation of toxic lipid peroxides contributing to the endothelial dysfunction and hypertension of preeclampsia.
We investigated the infection dynamics of 2 influenza A(H1N1) virus isolates from the swine 1A.3.3.2 (pandemic 2009) and 1C (Eurasian, avian-like) lineages. The 1C-lineage virus, A/Pavia/65/2016, ...although phylogenetically related to swine-origin viruses, was isolated from a human clinical case. This strain infected ferrets, a human influenza model species, and could be transmitted by direct contact and, less efficiently, by airborne exposure. Infecting ferrets and pigs (the natural host) resulted in mild or inapparent clinical signs comparable to those observed with 1A.3.3.2-lineage swine-origin viruses. Both H1N1 viruses could infect pigs and were transmitted to cohoused ferrets. Ferrets vaccinated with a human 2016–17 seasonal influenza vaccine were protected against infection with the antigenically matched 1A pandemic 2009 virus but not against the swine-lineage 1C virus. Our results reaffirm the need for continuous influenza A virus surveillance in pigs and identification of candidate human vaccine viruses.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Objectives This study sought to compare outcomes after surgical valvuloplasty and balloon dilation of the aortic valve in neonates and infants. Background Surgical techniques of aortic valve repair ...have improved and there is today controversy on the best approach to treat neonatal congenital aortic valve stenosis. Methods Retrospective review of data and follow-up of 123 consecutive neonates and infants (35 females, 88 males) undergoing intervention for congenital aortic stenosis. Results From 1977 to 2009, 123 consecutive neonates (<30 days) and infants (31 days to 1 year) underwent relief of congenital aortic stenosis. Median age at procedure was 27 days (6 to 76 days). Twenty-year survival was 80 ± 7%. Fifty-four patients required a re-intervention and freedom from re-intervention was 55 ± 6% at 10 years and 40 ± 6% at 20 years. By multivariate analysis, having the relief of stenosis by balloon valvuloplasty and undergoing initial treatment as a neonate were predictive of re-intervention. Freedom from re-intervention at 5 years was 27% after balloon valvuloplasty versus 65% after surgery. At latest follow-up, an additional 16 patients had moderate or severe stenosis and 8 had regurgitation. Freedom from re-intervention or stenosis was 39 ± 5% at 15 years. By multivariate analysis, balloon valvuloplasty (p < 0.001) and treatment as a neonate (p = 0.003) were again predictive of stenosis or re-intervention. Thirty-five patients ultimately needed a valve replacement. Significant predictor of the requirement of valve replacement was unicuspid aortic valve (p < 0.001). Freedom from valve replacement was 55 ± 7% at 20 years. Conclusions Surgical valvuloplasty remains the best approach to treat neonates and infants with congenital aortic stenosis. After surgery, a higher proportion of patients remain free of re-intervention than after interventional catheterization and the relief of their stenosis lasts longer.
Measles is a highly infectious and potentially dangerous disease. Before mass vaccination was started in the UK, measles caused an average of 100 deaths per year. Since the introduction of ...vaccination, vaccine uptake has risen from around 50% in 1968 to 76% in 1988. After the introduction of the combined measles, mumps, and rubella vaccine in 1988, vaccine uptake rose rapidly to a national average of 91% by 1998.
PDF
