3D non-driven magnetic reconnection at multiple separators.

Separators are important topological features of magnetic configuration for magnetic reconnection, commonly found in the solar plasma. They are located at the boundary shared among four distinctive flux domains; therefore, current layers easily build up around them. This paper aims to explore non-driven magnetic reconnection at multiple separators since little information is available about it. We have done two sets of experiments: non-resistive magnetohydrodynamic (MHD) relaxation and resistive MHD reconnection of a magnetic configuration consisting of two null points alongside their associated spines and three non-potential separators, which connect the same two null points. We used the LARE3D code for this purpose. The main current layers are formed along these separators where reconnection takes place. The reconnection occurs in two distinct phases: fast-strong and slow-weak. Most of the current dissipates at a fast rate, through Ohmic heating, during the fast-strong phase. The short-lived impulsive bursty reconnection events occur randomly in the slow-weak phase, while viscous heating exceeds Ohmic heating in this phase. The electric field component is parallel to field lines along the separators; likewise, the rate of reconnection along each of them evolved over time. However, work on separator reconnection has a strong potential to understand the underlying physics.

Guidelines on the use of fluoride for caries prevention in children: an updated EAPD policy document.

AIM: To update the exisitng European Academy of Paediatric Dentistry (EAPD) 2009 fluoride guidelines. METHODS: Experts met in Athens, Greece duirng November 2018 for the following groups: I Fluoride toothpastes, II Fluoride gels, rinses and varnishes, III Fluoridated milk, fluoridated salt, tablets/lozenges and drops, IV Water fluoridation. Systematic reviews and meta-analyses were reviewed and discussed for each of the groups. The GRADE system was used to assess the quality of evidence which was judged as HIGH, MODERATE, LOW or VERY LOW based on the assessment of eight criteria which can influence the confidence of the results. Following the quality assessment, GRADE was then used to indicate the strength of recommendation for each fluoride agent as STRONG or WEAK/CONDITIONAL. RESULTS: Parents must be strongly advised to apply an age-related amount of toothpaste and assist/supervise tooth brushing until at least 7 years of age. The EAPD strongly endorses the daily use of fluoride as a major part of any comprehensive programme for the prevention and control of dental caries in children. Regardless of the type of programme, community or individually based, the use of fluoride must be balanced between the estimation of caries-risk and the possible risks of adverse effects of the fluorides. Fluoride use is considered safe when the manufacturer's instructions are followed. Preventive programmes should be re-evaluated at regular intervals and adapted to a patient's or population's needs and risks. CONCLUSIONS: For the majority of European Countries, the EAPD recommends the appropriate use of fluoride toothpaste in conjunction with good oral hygiene to be the basic fluoride regimen.

Extreme ultraviolet imaging of three-dimensional magnetic reconnection in a solar eruption.

Magnetic reconnection, a change of magnetic field connectivity, is a fundamental physical process in which magnetic energy is released explosively, and it is responsible for various eruptive phenomena in the universe. However, this process is difficult to observe directly. Here, the magnetic topology associated with a solar reconnection event is studied in three dimensions using the combined perspectives of two spacecraft. The sequence of extreme ultraviolet images clearly shows that two groups of oppositely directed and non-coplanar magnetic loops gradually approach each other, forming a separator or quasi-separator and then reconnecting. The plasma near the reconnection site is subsequently heated from ∼1 to ≥5 MK. Shortly afterwards, warm flare loops (∼3 MK) appear underneath the hot plasma. Other observational signatures of reconnection, including plasma inflows and downflows, are unambiguously revealed and quantitatively measured. These observations provide direct evidence of magnetic reconnection in a three-dimensional configuration and reveal its origin.

After-brush rinsing protocols, frequency of toothpaste use: fluoride and other active ingredients.

The intra-oral retention or substantivity of active ingredients in toothpastes is important for their effectiveness, and this is influenced by product-related and user-related factors. Product-related factors include the formulation and the compatibility of active and other agents in the toothpaste and the concentration of the active ingredient. User-related factors include biological aspects such as salivary flow and salivary clearance, and behavioural aspects, such as frequency and duration of brushing, amount of toothpaste used and post-brushing rinsing behaviour. To date, product-related factors have dominated the research agenda for toothpastes, but user-related factors have the potential to significantly enhance or reduce the effectiveness of toothpaste. In this chapter, we will focus on two of the user-related factors that have been most widely studied: (1) frequency of toothbrushing and (2) post-brushing rinsing behaviour. We will then provide an overview of how evidence on these two behaviours has been used to produce guidance both for the profession and for the public, and make suggestions for the future direction of research in this area.

Comparison of seasonal phenol and p-cresol emissions from ground-level area sources in a dairy operation in central Texas.

Although there are more than 200 odor-causing volatile organic compounds (VOCs), phenol and p-cresol are two prominent odor-causing VOCs found downwind from concentrated animal feeding operations (CAFOs). The VOC emissions from cattle and dairy production are difficult to quantify accurately because of their low concentrations, spatial variability, and limitations of available instruments. To quantify VOCs, a protocol following US. Environmental Protection Agency (EPA) Method TO-14A has been established based on the isolation flux chamber method and a portable gas chromatograph (GC) coupled with a purge-and-trap system. The general objective of this research was to quantify phenol and p-cresol emission rates (ERs) from different ground-level area sources (GLASs) in a free-stall dairy during summer and winter seasons using this protocol. Two-week-long sampling campaigns were conducted in a dairy operation in central Texas. Twenty-nine air samples were collected during winter and 37 samples were collected during summer from six specifically delineated GLASs (barn, loafing pen, lagoon, settling basin, silage pile, and walkway) at the free-stall dairy. Thirteen VOCs were identified during the sampling period and the GC was calibrated for phenol and p-cresol, the primary odorous VOCs identified. The overall calculated ERs for phenol and p-cresol were 2656 +/- 728 and 763 +/- 212 mg hd(-1) day(-1), respectively, during winter. Overall phenol and p-cresol ERs were calculated to be 1183 +/- 361 and 551 +/- 214 mg hd(-1) day(-1), respectively, during summer. In general, overall phenol and p-cresol ERs during winter were about 2.3 and 1.4 times, respectively, higher than those during summer.

Post-brushing rinsing for the control of dental caries: exploration of the available evidence to establish what advice we should give our patients.

Post-tooth brushing rinsing behaviours have the potential to either reduce or enhance the effectiveness of fluoride toothpaste and show wide variation in the general population. There is a lack of high-quality evidence to support definitive guidance in this area. However, the currently available international guidelines provide consistent recommendations despite the limited evidence. To explore the available evidence base and recommendations on optimal post-brushing rinsing behaviour relating to the use of both water and mouth rinses, a meeting was held between the authors and other experts. This paper reports the consensus views of those present at the meeting concerning what advice we should give our patients. A full list of meeting attendees is provided at the end of this article.

Role of circulating fibroblast growth factor-2 in lipopolysaccharide-induced acute kidney injury in mice.

Fibroblast growth factor-2 (FGF-2) is an angiogenic growth factor involved in renal growth and regeneration. Previous studies in rodents revealed that single intrarenal injections of FGF-2 improved the outcome of acute kidney injury (AKI). Septic children usually show elevated plasma levels of FGF-2, and are at risk of developing AKI. However, the role of circulating FGF-2 in the pathogenesis of AKI is not well understood. We have developed a mouse model to determine how FGF-2 released into the circulation modulates the outcome of AKI induced by lipopolysaccharide (LPS). Young FVB/N mice were infected with adenoviruses carrying a secreted form of human FGF-2 or control LacZ vectors. Subsequently, when the circulating levels of FGF-2 were similar to those seen in septic children, mice were injected with a non-lethal dose of LPS or control buffer. All mice injected with LPS developed hypotension and AKI, from which they recovered after 5 days. FGF-2 did not improve the outcome of AKI, and induced more significant renal proliferative and apoptotic changes during the recovery phase. These findings suggest that circulating FGF-2 may not necessarily prevent the development or improve the outcome of AKI. Moreover, the renal accumulation of FGF-2 might cause further renal damage.

Effect of ozonation on particulate matter in broiler houses.

The effects of ozonation on particulate matter were studied on a commercial broiler farm. The farm consisted of 4 identical tunnel-ventilated houses (12.8×152.4 m): 2 houses were treated with O3 (maximum concentration 0.1 ppm) and the other 2 served as control units. The particle size distributions of total suspended particulate (TSP) samples from both control and treated houses were found to have very similar profiles with no statistical difference. The TSP concentrations were significantly higher in treated houses as compared with those in control houses, and the mean of the differences was 5.50 mg/m3. In both treated and control houses, there were substantial vertical TSP concentration gradients and the concentrations decreased with height. At broiler chicken height (0.28 m), TSP concentrations were 13±3 mg/m3 in control houses and 17±2 mg/m3 in treated houses. At human breathing height (1.55 m), TSP concentrations were 8±4 mg/m3 in control houses and 7±2 mg/m3 in treated houses. Particle phase NH4+ concentrations were higher in treated houses (ranging from 0.59 to 42.01 mg/m3 with mean=17.49 mg/m3) than in control houses (ranging from 0.34 to 13.55 mg/m3 with mean=4.42 mg/m3). The TSP samples from locations in the vicinity of the farm showed higher concentrations downwind than that upwind, but there were no significant differences observed among different ambient locations for TSP NH4+ concentrations. The results from this study did not show that direct application of ozonation technique has beneficial effects for particulate matter control in broiler houses.

The caries-preventive effect of chlorhexidine varnish in children and adolescents: a systematic review.

AIMS: Our purpose was to systematically review the literature on the effectiveness of chlorhexidine varnish for preventing dental caries in children and adolescents and to determine its effectiveness compared to fluoride varnish. METHODS: MEDLINE, EMBASE and the Cochrane Library were searched through December 2009 to identify relevant randomised trials with blind outcome assessment and a minimum duration of 1 year. The search was later updated in MEDLINE and the Cochrane Library to March 19th, 2010. Risk of bias of the included trials was assessed. The primary outcome was the caries increment. RESULTS: Twelve trials met the inclusion criteria for the review. There was considerable variation between trials in the concentration and frequency of application of the chlorhexidine varnish, in baseline caries levels and in background exposure to fluoride. Six parallel-group trials reported no statistically significant difference in caries increment in permanent teeth with the application of chlorhexidine varnish compared to placebo or no treatment. The results of 4 split-mouth trials were conflicting: 2 trials found no significant difference in caries increment and 2 reported statistically significant results in favour of chlorhexidine varnish. One trial of the effect of chlorhexidine varnish in primary teeth demonstrated a statistically significant reduction in caries increment. The results of 1 trial comparing chlorhexidine varnish with fluoride varnish for preventing caries in adolescents were equivocal. CONCLUSION: Evidence regarding the effectiveness of chlorhexidine varnish for preventing caries is inconclusive. Further well-conducted randomised trials are required before chlorhexidine varnish can be recommended for caries prevention.

Water fluoridation.

AIM: This was to present a summary of the evidence from systematic reviews of the effectiveness and safety of water fluoridation. METHODS: A search for relevant systematic reviews was conducted using the terms Fluoridation [Mesh] OR "water fluoridation" OR fluoridation OR (water AND fluoride) and was run from 01/01/2000 to 17/10/2008 in Pubmed, Embase, the Cochrane Database of Systematic Reviews and the Database of Abstracts of Reviews of Effects in the Cochrane Library. The quality of the systematic reviews was assessed using Scottish Intercollegiate Guideline Network (SIGN) methodology checklists for systematic reviews. Websites of guideline organisations were also searched for relevant evidence-based guidelines, which were appraised using the AGREE instrument. RESULTS: Of the 59 publications identified, 3 systematic reviews and 3 guidelines were included in this review. While the reviews themselves were of good methodological quality, the studies included in the reviews were generally of moderate to low quality. The results of the three reviews showed that water fluoridation is effective at reducing caries in children and adults. With the exception of dental fluorosis, no association between adverse effects and water fluoridation has been established. Water fluoridation reduces caries for all social classes, and there is some evidence that it may reduce the oral health gap between social classes. CONCLUSION: Water fluoridation, where technically feasible and culturally acceptable, remains a relevant and valid choice as a population measure for the prevention of dental caries.

A urinary biomarker profile for children with HIV-associated renal diseases.

Human immunodeficiency virus (HIV)-infected children are at risk of developing several types of renal diseases, including HIV-associated nephropathy (HIVAN), which is usually seen during late stages of infection in children with a high viral load. This disease is defined by the presence of proteinuria associated with mesangial hyperplasia and/or global-focal segmental glomerulosclerosis combined with microcystic transformation of the renal tubules. Because HIVAN can have an insidious clinical onset, renal biopsy is the only definitive way of establishing a diagnosis. Given the risk of performing this procedure in HIV-infected children with other AIDS-defining illness, we sought to identify informative biomarkers such as growth factors in the urine of 55 HIV-infected children that might be predictive of the extent and activity of the renal lesions characteristic of HIVAN. We found that the levels of epidermal growth factor were lower in the urine of children with renal disease, whereas levels of fibroblast growth factor-2 and metalloproteinase-2 were higher as compared with those levels in infected children without renal disease. Similar changes were observed in HIV-Tg26 mice correlating with the progression of renal disease in this model of HIVAN. Our findings suggest that this urinary growth factor profile may be useful in facilitating the diagnosis of HIV-infected children at risk of developing HIVAN when interpreted in the appropriate clinical setting.

Evaluation of a community fissure sealant programme in County Meath, Ireland.

OBJECTIVE: To evaluate the fissure sealant programme operated by the North Eastern Health Board Dental Service in County Meath, Republic of Ireland. The fissure sealant programme forms part of the school dental service aimed at children in first class (age group 6-7 years). DESIGN: Cross sectional study with retrospective analysis of dental records. CLINICAL SETTING: Schools in County Meath in 1999. PARTICIPANTS: Children in fourth class (mean age 9.6 years) in the school year 1999/2000 who had participated in the fissure sealant programme in the school year 1996/97. MAIN OUTCOME MEASURES: Sealant retention using the criteria of Simonsen. RESULTS: The mean age of sealant was 2.3 years. Fifty six percent of sealants were completely retained, 27% were partially retained and 12.8% were missing. The majority (73%) of children had some sealant on at least one tooth. Caries experience in previously sealed teeth was low (2.9%). Children who had all four first permanent molars sealed had a significantly lower DMFT (visual) than those who had no sealants (Wilcoxan p < 0.0001). CONCLUSION: Despite lack of maintenance of sealants in this study, retention rates compared favourably with similar international studies and caries experience in previously sealed teeth was low. The use of a written sealant policy and protocol for sealant application and equipment maintenance could further improve retention rates. Children who had no sealants had significantly poorer dental health than children who had all four first permanent molars sealed.

Conduct of labor and rupture of the sphincter ani.

OBJECTIVE: To determine whether the conduct of the second stage of labor and delivery technique influences the incidence of rupture of the anal sphincter. MATERIAL AND METHOD: A total of 1072 primipara delivered vaginally at term at Rigshospitalet in 1998. A questionnaire on prenatal risk factors, conduct of the second stage of labor, and delivery technique was completed by the attending midwife immediately after delivery in 90 cases with rupture of the sphincter and in two subsequent controls (n = 164), matched by use of vacuum extractor and episiotomy. RESULTS: Partial or total sphincter rupture was found in 8.4% of primipara who delivered vaginally, in 20.9% of those delivered by vacuum extraction, and in 6.4% of those with episiotomy only. The prenatal risk factors--maternal age, birth weight, shoulder dystocia, and edema of the perineum were found to have a statistically significant effect on the incidence of rupture of the sphincter ani. In non-instrumental vaginal deliveries easing of the perineum over the caput as it advanced helped prevent a rupture of the anal sphincter. Vacuum extraction performed with the woman in a semi-recumbant position was associated with an increased risk of rupture of the anal sphincter, whereas attention to the perineum during extraction decreased the risk. CONCLUSIONS: The significant effect of prenatal risk factors did not explain a correlation between delivery technique and rupture of the sphincter ani. The present study indicates that a reduction in the incidence of sphincter rupture may be accomplished by improved obstetric care: fewer vacuum extractions and improved delivery technique.

Pushing method in the expulsive phase of labor. A randomized trial.

BACKGROUND: Pushing in the second stage of labor can be forced or follow the spontaneous urge to bear down. Recent studies have shown that spontaneous pushing results in a longer second stage, fewer CTG changes, higher arterial pH and less damage to the birth canal. METHOD: Randomized trial of spontaneous vs. forced pushing in 350 primiparous women. RESULTS: There was no difference between the randomized groups in duration of second stage of labor, umbilical arterial pH or damage to the birth canal. Of the women allotted to spontaneous pushing, 65.6% used the closed glottis technique for more than half the expulsive phase. When dividing the women into two groups according to the actual pushing technique used most, open or closed glottis, it turned out that women who used the open glottis technique had a shorter second stage of labor and gave birth to infants with lower birth weight. CONCLUSION: Recommending of spontaneous bearing down during the expulsive phase of labor did not result in a significant difference in duration of the second stage of labor, fetal arterial pH or less damage to the birth canal. Women who chose the open glottis technique had a shorter expulsive phase and gave birth to smaller infants than those who used the closed glottis technique.

Determination of contamination of a chemical warfare-proof operating theatre with volatile anaesthetic agents and assessment of anaesthetic gas scavenging systems.

Three types of anaesthetic waste scavenging systems (active antipollution system, Papworth Block passive system and activated charcoal absorber system) were compared with a non-scavenging control to assess their effectiveness in reducing waste halothane concentrations in a chemical warfare-proof operating theatre. All three systems were found to reduce the level of pollution significantly.

[Cardiotocographic monitoring of deliveries. A prospective comparative study of 2 types of electrodes]. / Kardiotokografisk fødselsovervågning. En prospektiv sammenlignende undersøgelse af to elektrodetyper.

The number of electrodes employed, the frequency of reapplication, the technical quality of monitoring and the complications of use of spiral electrodes and Copeland electrodes for cardiotocographic monitoring of deliveries are assessed in a prospective randomized investigation. The number of electrodes employed and the frequency of reapplications were significantly lower employing Copeland electrodes. Similarly, the electrode signal was significantly better as assessed by the percentage of the duration of monitoring in which the cardiotocogram did not register during the second stage of labour on account of poor electrode signals. No differences were found in the frequencies of complications or subjective discomfort in the mother on employing the two types of electrodes.

Dust emissions in cattle feedlots.

Dust emissions were measured at three Texas cattle feedlots on 15 occasions in 1987 to determine concentrations of total suspended particulate matter (TSP) and dust with 10 microns or less aerodynamic particle size (PM-10). Net feedlot dust concentrations (downwind minus upwind) ranged from 15.7 to 1,700.1 micrograms per m3 and averaged 412.4 +/- 271.2 micrograms per m3, which is about 37 per cent less than was determined in feedlot dust research in California approximately 17 years earlier. Upwind concentrations averaged 22 per cent of the downwind concentrations. Feedlot dust concentrations were generally highest in early evening and lowest in early morning. Using the Wedding and Andersen-321A PM-10 samplers, the PM-10 dust concentrations were 19 and 40 per cent, respectively, of mean TSP concentrations in direct comparisons. There was good correlation between PM-10 and TSP concentrations. Although dust concentrations decreased with increasing moisture, the correlation coefficients were relatively low. Odor intensity appeared to increase with decreasing net dust concentrations, perhaps due to moisture influences. Mean particle sizes of feedlot dust were 8.5 to 12.2 microns on a particle volume basis and 2.5 to 3.4 microns on a population basis. Respirable dust (below 2 microns) represented only 2.0 to 4.4 per cent of total dust on a particle volume basis. Under conditions of these experiments, the feedlots often exceeded both state and federal (U.S. Environmental Protection Agency) standards for TSP concentrations and for PM-10 concentrations measured using the Andersen-321A sampler. However, feedlots were below the new U.S. Environmental Protection Agency standards when the Wedding PM-10 sampler was used for measuring dust emissions.

Changes in relative biological effectiveness with depth of the Clatterbridge neutron therapy beam.

We have measured the biological equivalence of the Clatterbridge neutron therapy beam [p(62)-Be] and the Hammersmith neutron therapy beam [d(16)-Be] using the mouse intestinal crypt assay. The ratio (NDR) of Clatterbridge neutron (n + gamma) dose relative to Hammersmith neutron dose (n + gamma) was found to be 1.2-1.13 over a dose/fraction range of 1.8-9 Gy at 2 cm deep in a Perspex phantom. It is shown that the effectiveness of the Clatterbridge beam was reduced with penetration into the phantom because of hardening of the beam to a maximum reduction of 11% at 12 cm deep in the phantom. The hardening of the beam with depth of penetration will need to be taken into account by clinicians in assessing the tumour dose and tissue tolerance. Relative biological effectiveness values for the Clatterbridge and Hammersmith neutron beams were also measured. All neutron doses for both Hammersmith and Clatterbridge beams are total doses (n + gamma) which comply with the European protocol for neutron dosimetry and include the gamma-ray component of dose.