Diffusion and solubility of oxygen in silver

The diffusion and solubility of oxygen in Ag in the temperature range between 412 and 862 C was determined. The following interpolation formula was found for the solubility: L = 8.19.1/100.exp(-11 860/RT)Mol O2/g.At.Ag.at 1/.5. The process obeys the Sieverts square root law within the limits of error. The dissolution of oxygen in Ag may be accompanied by the dissociation of the oxygen molecules into atoms. The tests on Ag-foils reveal that below a temperature of about 500 C a higher solubility is simulated by the adsorption of oxygen. The diffusion coefficient of oxygen in silver obeys the following equation: D = 2.72.1/100.exp(-11 000/RT)sq cm/s. The relatively low activation energy of 11 kcal/g.At suggests that the diffusion of oxygen takes places over interstitial sites

Oral microbiota carriage in patients with multibracket appliance in relation to the quality of oral hygiene

Background: The present study aimed to investigate the prevalence of oral microbiota (Candida species (spp.), Streptococcus mutans, and Lactobacilli) in patients with multibracket (MB) appliances in relation to the quality of oral hygiene. Saliva and plaque samples were collected from three groups of 25 patients each (good oral hygiene (GOH), poor oral hygiene (POH), and poor oral hygiene with white spot lesions (POH/WSL)). Counts of colony forming units (CFU) of the investigated oral microbiota were compared using Chi-square and Mann–Whitney U tests. Results: Both saliva and plaque samples showed a high prevalence of Candida spp. in all patients (saliva: 73.4 %, plaque: 60.9 %). The main Candida species was C. albicans. The salivary CFU of Candida spp. in the GOH group was significantly lower than that in the POH group (p?=?0.045) and POH/WSL group (p?=?0.011). S. mutans was found in the saliva and plaque samples of all patients. Lactobacilli were found in the saliva samples of all patients and in 90.7 % of the plaque samples. In the saliva samples, the CFU of Lactobacilli were more numerous in the POH and POH/WSL groups than in the GOH group (p?=?0.047). Conclusions: The investigated sample of patients showed a high carriage of oral Candida spp. Patients with WSL formation during MB appliance treatment exhibited higher counts of Candida and Lactobacilli compared with patients with good oral hygiene. Independent of oral hygiene quality, S. mutans was detected in all patients

The association between prenatal famine, DNA methylation and mental disorders: a systematic review and meta-analysis

Background Undernutrition in pregnant women is an unfavorable environmental condition that can affect the intrauterine development via epigenetic mechanisms and thus have long-lasting detrimental consequences for the mental health of the offspring later in life. One epigenetic mechanism that has been associated with mental disorders and undernutrition is alterations in DNA methylation. The effect of prenatal undernutrition on the mental health of adult offspring can be analyzed through quasi-experimental studies such as famine studies. The present systematic review and meta-analysis aims to analyze the association between prenatal famine exposure, DNA methylation, and mental disorders in adult offspring. We further investigate whether altered DNA methylation as a result of prenatal famine exposure is prospectively linked to mental disorders. Methods We conducted a systematic search of the databases PubMed and PsycINFO to identify relevant records up to September 2022 on offspring whose mothers experienced famine directly before and/or during pregnancy, examining the impact of prenatal famine exposure on the offspring’s DNA methylation and/or mental disorders or symptoms. Results The systematic review showed that adults who were prenatally exposed to famine had an increased risk of schizophrenia and depression. Several studies reported an association between prenatal famine exposure and hyper- or hypomethylation of specific genes. The largest number of studies reported differences in DNA methylation of the IGF2 gene. Altered DNA methylation of the DUSP22 gene mediated the association between prenatal famine exposure and schizophrenia in adult offspring. Meta-analysis confirmed the increased risk of schizophrenia following prenatal famine exposure. For DNA methylation, meta-analysis was not suitable due to different microarrays/data processing approaches and/or unavailable data. Conclusion Prenatal famine exposure is associated with an increased risk of mental disorders and DNA methylation changes. The findings suggest that changes in DNA methylation of genes involved in neuronal, neuroendocrine, and immune processes may be a mechanism that promotes the development of mental disorders such as schizophrenia and depression in adult offspring. Such findings are crucial given that undernutrition has risen worldwide, increasing the risk of famine and thus also of negative effects on mental health

Therapy-Related Myeloid Neoplasms in Patients Treated for Hodgkin Lymphoma

Hodgkin lymphoma (HL) is a malignancy of the lymphatic system with an incidence of 2-3/100.000/year in developed countries. With modern multi-agent chemotherapy protocols optionally combined with radiotherapy (RT), 80% to 90% of HL patients achieve long-term remission and can be considered cured. However, current standard approaches bear a considerable risk for the development of treatment-related late effects. Thus, one major focus of current clinical research in HL is reducing the incidence of these late effects that include heart failure, infertility, chronic fatigue and therapy-related myelodysplastic syndrome/acute myeloid leukemia (t-MDS/t-AML). In previous analyses, t-MDS/t-AML after treatment for HL was associated with a poor prognosis. Nearly all patients died rapidly after diagnosis. However, more recent analyses indicated an improved outcome among patients with t-MDS/t-AML who are eligible for modern anti-leukemic treatment and allogeneic stem cell transplantation (aSCT). This article gives an overview of recent reports on the incidence and the treatment of t-MDS/t-AML after HL therapy and describes the efforts currently made to reduce the risk to develop this severe late effect

Bilateralizing multilateral aid? Aid allocation by World Bank trust funds

Over the last decade, donors of foreign aid quadrupled their annual contributions to trust funds at the World Bank. Concerns have been raised that trust fund aid may undermine the incentives associated with IDA s performance-oriented aid allocation. Moreover, the earmarking of contributions to donors preferred recipient countries might bilateralize multilateral aid, potentially to the detriment of aid effectiveness. Using new data on World Bank trust fund disbursements for the 2002-2012 period, we test whether trust fund aid substitutes for IDA inflows, and, as official narratives suggest, for other aid inflows. We also investigate the bilateralization hypothesis by comparing multilateral core aid to trust fund disbursements. Trust fund aid is generally not allocated according to World Bank s Country Policy and Institutional Assessment (CPIA) index, which could undermine the incentives generated of the IDA allocation mechanism. This result is confirmed when we consider the health, education, and environment sector separately using sector-specific CPIA scores and IDA aid. We do not find systematic evidence that trust funds are to a larger degree motivated by political and economic motives

Parallel Streams of Nonlinear Congruential Pseudorandom Numbers

AbstractThis paper deals with the general nonlinear congruential method for generating uniform pseudorandom numbers, in which permutation polynomials over finite prime fields play an important role. It is known that these pseudorandom numbers exhibit an attractive equidistribution and statistical independence behavior. In the context of parallelized simulation methods, a large number of parallel streams of pseudorandom numbers with strong mutual statistical independence properties are required. In the present paper, such properties of parallelized nonlinear congruential generators are studied based on the discrepancy of certain point sets. Upper and lower bounds for the discrepancy both over the full period and over (sufficiently large) parts of the period are established. The method of proof rests on the classical Weil bound for exponential sums

Geopolitics, Aid and Growth

We investigate the effects of short-term political motivations on the effectiveness of foreign aid. Specifically, we test whether the effect of aid on economic growth is reduced by the share of years a country has served on the United Nations Security Council (UNSC) in the period the aid has been committed, which provides quasi-random variation in aid. Our results show that the relationship of aid with growth is significantly lower when aid has been committed during a country’s tenure on the UNSC. We derive two conclusions from this. First, short-term political favoritism reduces growth. Second, political interest variables are inadequate as instruments for overall aid, raising doubts about a large number of results in the aid effectiveness literature

The Effects of Trade, Aid, and Investment on China's Image in Developing Countries

One goal of China’s Go Out policy is to create goodwill in countries around the world. At the same time, China’s growing economic engagement has provoked much criticism. This paper is the first to study whether these activities change the attitudes of individuals in developing countries towards China at both the national and subnational level. Using repeated cross-sectional survey data from the Latinobarómetro, we analyze whether and how growing amounts of exports, foreign aid, and foreign direct investment from China to Latin America affect opinions on China within 18 Latin American countries over the 2002-2013 period. We run instrumental-variables regressions by exploiting exogenous variation in the supply of Chinese exports, aid, and investment proxied by China’s market penetration of developing countries outside Latin America. In contrast to the widespread criticism, we do not find evidence that China’s growing economic activities in the respective countries deteriorate average attitudes towards China — neither at the national nor the provincial level. However, our results show that the young, educated, and economically privileged population develops more positive views of China. We interpret this as evidence that China’s economic engagement creates winners and losers