214 research outputs found
Resonant-Frequency Discharge in a Multi-Cell Radio Frequency Cavity
We are reporting experimental results on a microwave discharge operating at resonant frequency in a multi-cell radio frequency (RF) accelerator cavity. Although the discharge operated at room temperature, the setup was constructed so that it could be used for plasma generation and processing in fully assembled active superconducting radio-frequency cryo-module. This discharge offers a mechanism for removal of a variety of contaminants, organic or oxide layers, and residual particulates from the interior surface of RF cavities through the interaction of plasma-generated radicals with the cavity walls. We describe resonant RF breakdown conditions and address the issues related to resonant detuning due to sustained multi-cell cavity plasma. We have determined breakdown conditions in the cavity, which was acting as a plasma vessel with distorted cylindrical geometry. We discuss the spectroscopic data taken during plasma removal of contaminants and use them to evaluate plasma parameters, characterize the process, and estimate the volatile contaminant product removal
Electron Density Measurements in a Pulse-Repetitive Microwave Discharge in Air
We have developed a technique for absolute measurements of electron density in pulse-repetitive microwave discharges in air. The technique is based on the time-resolved absolute intensity of a nitrogen spectral band belonging to the Second Positive System, the kinetic model and the detailed particle balance of the N2C3Πu (ν role= presentation \u3eν = 0) state. This new approach bridges the gap between two existing electron density measurement methods (Langmuir probe and Stark broadening). The electron density is obtained from the time-dependent rate equation for the population of N2C3Πu (ν role= presentation \u3eν = 0) using recorded waveforms of the absolute C3Πu → B3Πg (0-0) band intensity, the forward and reflected microwave power density. Measured electron density waveforms using numerical and approximated analytical methods are presented for the case of pulse repetitive planar surface microwave discharge at the aperture of a horn antenna covered with alumina ceramic plate. The discharge was generated in air at 11.8 Torr with a X-band microwave generator using 3.5 μs microwave pulses at peak power of 210 kW. In this case, we were able to time resolve the electron density within a single 3.5 μs pulse. We obtained (9.0 ± 0.6) × 1013 cm–3 for the peak and (5.0 ± 0.6) × 1013 cm–3 for the pulse-average electron density. The technique presents a convenient, non-intrusive diagnostic method for local, time-defined measurements of electron density in short duration discharges near atmospheric pressures
Shotgun metagenomics reveals differences in antibiotic resistance genes among bacterial communities in Western Balkans glacial lakes sediments
Long-term overuse of antibiotics has driven the propagation and spreading of antibiotic resistance genes (ARGs) such as efflux pumps in the environment, which can be transferred to clinically relevant pathogens. This study explored the abundance and diversity of ARGs and mobile genetic elements within bacterial communities from sediments of three Western Balkans glacial lakes: Plav Lake (high impact of human population), Black Lake (medium impact of human population) and Donje Bare Lake (remote lake, minimal impact of human population) via shotgun metagenomics. Assembled metagenomic sequences revealed that Resistance-Nodulation-Division (RND) efflux pumps genes were most abundant in metagenome from the Plav Lake. The Integron Finder bioinformatics tool detected 38clusters ofattCsiteslackingintegron-integrases (CALIN) elements: 20 from Plav Lake, four from Black Lake and 14 from Donje Bare Lake. A complete integron sequence was recovered only from the assembled metagenome from Plav Lake. Plasmid contents within the metagenomes were similar, with proportions of contigs being plasmid-related: 1.73% for Plav Lake, 1.59% for Black Lake and 1.64% for Donje Bare Lake. The investigation showed that RNDs and mobile genetic elements content correlated with human population impact
Schistosomiasis and soil-transmitted helminth infections in schoolchildren in north-eastern Democratic Republic of the Congo
BACKGROUND: There is a paucity of epidemiological data pertaining to schistosomiasis and soil-transmitted helminth (STH) infections in the Democratic Republic of the Congo (DRC).
METHODS: A cross-sectional survey was carried out in the north-eastern part of DRC enrolling 400 schoolchildren aged 9-14 years. Stool and urine samples were subjected to standard diagnostic methods and examined under a microscope for helminth eggs.
RESULTS: Four out of five children were infected with at least one helminth species. Schistosoma mansoni was the predominant species (57.8%). Urine examinations were all negative for S. haematobium.
CONCLUSIONS: S. mansoni and STH infections are highly endemic in the surveyed part of the DRC, calling for interventions in school-aged children
6-hydroxydopamine lesions of the striatum lead to the alterations of dopamine receptor mrna in parkinsonian rats
The effects of four-site intrastriatal 6-hydroxydopamine (6-OHDA) lesions were examined in adult male rats. Five days after the lesions the animals were checked for specific rotational behavior induced by middle dose of amphetamine and the results confirmed the effectiveness of the lesions. The RNAs from the striatum were isolated at different time points after the lesion, and the RT-PCR analyse were performed for the D1 and D2 receptor mRNA. The results show a decline in the D2 receptor mRNA level (40%) at 6 h and 24 h points while this change was not observed seven days after the lesion. In contrast, no statistically significant changes in the level of the D1 receptor mRNA after the lesion at any time point were found.Ispitivani su efekti četiri ubodne 6-hidroksidopaminske (6-OHDA) lezije striatuma kod odraslih mužjaka pacova. Pet dana nakon lezije, životinje su testirane na specifično rotaciono ponaš anje pod uticajem srednje doze amfetamina i rezultati su potvrdili efikasnost lezije. RNK iz striatuma su izolovane u različitim vremenskim tačkama nakon lezije i urađena je RT-PCR analiza iRNK za D1 i D2 dopaminske receptore. Rezultati pokazuju smanjivanje nivoa iRNK za D2 receptor (40%) 6 h i 24 h nakon lezije, dok sedam dana nakon lezije nema promena. Za razliku od ovih rezultata, u nivou iRNK za D1 receptor ne postoje statistički značajne razlike u bilo kojoj vremenskoj tački
Spectral changes of brain activity in rat offspring exposed to aluminium during gestation and lactation
Exposure to aluminium during gestation causes changes in mammalian brain development and behavior. Our aim was to perform spectral analysis on electrocortical activity of Sprague Dawley male pups (30±3 days of age) whose mothers were treated with aluminium during gestation and lactation. There was a higher presence of power spectra in the delta range of parietal electrocortical activity, a lower presence in the theta range and increased values of the parameter DT as the ratio of delta to theta range in pups indirectly exposed to aluminium (whose mothers were drinking a 0.5% water solution of aluminium chloride during the gestation and lactation periods), compared to controls.Izlaganje dejstvu aluminijuma tokom gestacije i laktacije može dovesti do promena u razviću mozga i ponašanja kod sisara. Naš cilj je bio da se uradi spektralna analiza elektrokortikalne aktivnosti mladih Sprague Dawley pacova muškog pola (starosti 30±3 dana) čije su majke bile tretirane aluminijumom tokom gestacije i laktacije. U poređenju sa kontrolom, kod mladih pacova koji su bili indirektno trovani aluminijumom (čije su majke pile 0,5 % vodeni rastvor AlCl3 tokom gestacionog i laktacionog perioda) postoji veća zastupljenost delta ritma aktivnosti kore velikog mozga, manje prisustvo teta ritma, kao i porast parametra DT kao odnos između delta i teta opsega.Projekat ministarstva br. 14302
Voltammetric and Quantum Investigation of Selected Succinimides
A series of succinimide derivatives were studied using the cyclic and square wave voltammetry. Density function theory was used in order to determinate which of the structural parameters influence the electrochemical activity. The quantum chemical calculations of the investigated succinimides were linked with the experimental electrochemical data and used to propose the oxidation mechanism. The most active among studied succinimides is 1,3-diphenylsuccinimide. The results obtained from the cyclic and square wave voltammetry and quantum chemical calculations indicate that the investigated compounds undergo oxidation by irreversible, diffusion controlled process including transfer of 1e(-) and 1 proton. The voltammetric and DFT results signify that the mechanism of electrochemical oxidation of all compounds involve the conversion of carbonyl-methyne-phenyl segment or methylene group in free radical. This conversion proceeds by the loss of one proton one electron process
Transcriptional Auto-Regulation of RUNX1 P1 Promoter
RUNX1 a member of the family of runt related transcription factors (RUNX), is essential for hematopoiesis. The expression of RUNX1 gene is controlled by two promoters; the distal P1 promoter and the proximal P2 promoter. Several isoforms of RUNX1 mRNA are generated through the use of both promoters and alternative splicing. These isoforms not only differs in their temporal expression pattern but also exhibit differences in tissue specificity. The RUNX1 isoforms derived from P2 are expressed in a variety of tissues, but expression of P1-derived isoform is restricted to cells of hematopoietic lineage. However, the control of hematopoietic-cell specific expression is poorly understood. Here we report regulation of P1-derived RUNX1 mRNA by RUNX1 protein. In silico analysis of P1 promoter revealed presence of two evolutionary conserved RUNX motifs, 0.6kb upstream of the transcription start site, and three RUNX motifs within 170bp of the 5\u27UTR. Transcriptional contribution of these RUNX motifs was studied in myeloid and T-cells. RUNX1 genomic fragment containing all sites show very low basal activity in both cell types. Mutation or deletion of RUNX motifs in the UTR enhances basal activity of the RUNX1 promoter. Chromatin immunoprecipitation revealed that RUNX1 protein is recruited to these sites. Overexpression of RUNX1 in non-hematopoietic cells results in a dose dependent activation of the RUNX1 P1 promoter. We also demonstrate that RUNX1 protein regulates transcription of endogenous RUNX1 mRNA in T-cell. Finally we show that SCL transcription factor is recruited to regions containing RUNX motifs in the promoter and the UTR and regulates activity of the RUNX1 P1 promoter in vitro. Thus, multiple lines of evidence show that RUNX1 protein regulates its own gene transcription
Experience and lessons from health impact assessment guiding prevention and control of HIV/AIDS in a copper mine project, northwestern Zambia
To avoid or mitigate potential project-related adverse health effects, the Trident copper project in Kalumbila, northwestern Zambia, commissioned a health impact assessment. HIV was identified a priority health issue based on the local vulnerability to HIV transmission and experience from other mining projects in Africa. Hence, an HIV/AIDS management plan was developed, including community and workplace interventions, with HIV testing and counselling (HTC) being one of the key components. We present trends in HTC data over a 4-year period.; In 13 communities affected by the Trident project, HTC was implemented from 2012 onwards, using rapid diagnostic tests, accompanied by pre- and post-test counselling through trained personnel. In addition, HTC was initiated in the project workforce in 2013, coinciding with the launch of the mine development. HTC uptake and HIV positivity rates were assessed in the study population and linked to demographic factors using regression analysis.; In total, 11,638 community members and 5564 workers have taken up HTC with an increase over time. The HIV positivity rate in the community was 3.0% in 2012 and 3.4% in 2015, while positivity rate in the workforce was 5.2% in 2013 and 4.3% in 2015. Females showed a significantly higher odds of having a positive test result than males (odds ratio (OR)Â =Â 1.96, 95% confidence interval (CI): 1.55-2.50 among women in the community and ORÂ =Â 2.90, 95% CI: 1.74-4.84 among women in the workforce). HTC users in the 35-49Â years age group were most affected by HIV, with an average positivity rate of 6.6% in the community sample and 7.9% in the workforce sample. These study groups had 4.50 and 4.95 higher odds of being positive, respectively, compared to their younger counterparts (15-24Â years).; While HTC uptake increased five-fold in the community and almost three-fold in the workplace, the HIV positivity rates were insignificantly higher in 2015 compared to 2012. Our data can be used alongside other surveillance data to track HIV transmission in this specific context. Guided by the health impact assessment, the HIV prevention and control programme was readily adapted to the current setting through the identification of socioeconomic and environmental determinants of health
The Structural and Functional Capacity of Ruminal and Cecal Microbiota in Growing Cattle Was Unaffected by Dietary Supplementation of Linseed Oil and Nitrate
peer-reviewedMicroorganisms in the digestive tract of ruminants differ in their functionality and ability to use feed constituents. While cecal microbiota play an important role in post-rumen fermentation of residual substrates undigested in the rumen, limited knowledge exists regarding its structure and function. In this trial we investigated the effect of dietary supplementation with linseed oil and nitrate on methane emissions and on the structure of ruminal and cecal microbiota of growing bulls. Animals were allocated to either a CTL (control) or LINNIT (CTL supplemented with 1.9% linseed and 1.0% nitrates) diet. Methane emissions were measured using the GreenFeed system. Microbial diversity was assessed using amplicon sequencing of microbial genomic DNA. Additionally, total RNA was extracted from ruminal contents and functional mcrA and mtt genes were targeted in amplicon sequencing approach to explore the diversity of functional gene expression in methanogens. LINNIT had no effect on methane yield (g/kg DMI) even though it decreased methane production by 9% (g/day; P < 0.05). Methanobrevibacter- and Methanomassiliicoccaceae-related OTUs were more abundant in cecum (72 and 24%) compared to rumen (60 and 11%) irrespective of the diet (P < 0.05). Feeding LINNIT reduced the relative abundance of Methanomassiliicoccaceae mcrA cDNA reads in the rumen. Principal component analysis revealed significant differences in taxonomic composition and abundance of bacterial communities between rumen and cecum. Treatment decreased the relative abundance of a few Ruminococcaceae genera, without affecting global bacterial community structure. Our research confirms a high level of heterogeneity in species composition of microbial consortia in the main gastrointestinal compartments where feed is fermented in ruminants. There was a parallel between the lack of effect of LINNIT on ruminal and cecal microbial community structure and functions on one side and methane emission changes on the other. These results suggest that the sequencing strategy used here to study microbial diversity and function accurately reflected the absence of effect on methane phenotypes in bulls treated with linseed plus nitrate.This experiment is a part of a large collaborative project led by INRA granted by 11 companies: Adisseo France SAS, Agrial, Apis Gene, Deltavit, DSM Nutritional Products AG, Institut de l'Elevage, Lallemand, Moy Park Beef Orléans, Neovia, Techna France Nutrition, Valorex. This project aims to reduce enteric methane emission by nutrition. MP was the recipient of a PHC Ulysses travel scholarship to Ireland, provided by the French ministry of Foreign Affairs and International Development (Ministères des Affaires Etrangères et du Développement International, MAEDI) and the ministry of National Education, Higher Education, and Research (Ministère de l'Education Nationale, de l'Enseignement Supérieur et de la Recherche, MENESR). EM was the recipient of a FACCE-JPI scholarship
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