Influence of manufacturing technology on selected Al alloy

Diplomová práce se zabývá plátovanými plechy hliníkové slitiny EN AW-2024 v závislosti na různých dobách výdrže při vysokých teplotách během tepelného zpracování a jejími vlivy na materiálové vlastnosti. V první části diplomové práce v literární rešerši je zpracována teoretická část zabývající se jak čistým hliníkem, tak jeho slitinami a tepelným zpracováním vybraných slitin. Řešení experimentů bylo prováděné na normalizovaných zkušebních plochých tyčích po statické zkoušce v tahu, z kterých byly zpracované materiálové vlastnosti, studium lomových ploch a zhodnocení chemického složení v jednotlivých lokalitách slitiny, vzhledem na výskyt intermediárních fází.This thesis deals with clad sheets of aluminum alloy EN-AW 2024 in relation with different endurance times during heat treatment and its effects on material properties. In the introduction there is a literature review dealing with pure aluminum, its alloys and heat treatment of selected alloys. The experiments were carried out on standard flat test bars for static tensile test, from which were processed material properties. Also studies of fractured surfaces and evaluation of the chemical composition of alloys in different specific locations due to the occurrence of intermediate phases

Temporal dynamics of SARS-CoV-2 shedding in feces and saliva: a longitudinal study in Norfolk, United Kingdom during the 2021-2022 COVID-19 waves.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was originally described as a respiratory illness; however, it is now known that the infection can spread to the gastrointestinal tract, leading to shedding in feces potentially being a source of infection through wastewater. We aimed to assess the prevalence and persistence of SARS-CoV-2 in fecal and saliva samples for up to 7 weeks post-detection in a cohort of 98 participants from Norfolk, United Kingdom using RT-qPCR. Secondary goals included sequencing the viral isolates present in fecal samples and comparing the genetic sequence with isolates in the saliva of the same participant. Furthermore, we sought to identify factors associated with the presence of detectable virus in feces or saliva after a positive SARS-CoV-2 test. Saliva remained SARS-CoV-2-positive for longer periods compared to fecal samples, with all positive fecal samples occurring within 4 weeks of the initial positive test. Detectable virus in fecal samples was positively associated with the number of symptoms experienced by the individuals. Based on the genome sequencing and taxonomic classification of the virus, one donor had a distinct strain in feces compared to saliva on the same collection date, which suggests that different isolates could dominate different tissues. Our results underscore the importance of considering multiple biological samples, such as feces, in the detection and characterization of SARS-CoV-2, particularly in clinical procedures involving patient fecal material transplant. Such insights could contribute to enhancing the safety protocols surrounding the handling of patient samples and aid in devising effective strategies for mitigating the spread of coronavirus disease.ImportanceThis study provides critical insights into the dynamics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) shedding in fecal and saliva samples, demonstrating that while viral RNA is detectable shortly after diagnosis, its prevalence declines rapidly over the course of infection. Detection was more common among individuals with more concurrent symptoms, emphasizing the potential influence of symptom burden on viral persistence. By analyzing a United Kingdom-based cohort, this study fills a significant gap in the literature, which has largely focused on Asian and North American populations, offering a geographically unique perspective on viral shedding dynamics. Our findings contribute to a globally relevant understanding of SARS-CoV-2 shedding by revealing differences in shedding durations compared to studies from other regions. These differences highlight the need for geographically diverse research to account for variations in genetic background, immune response, and healthcare practices

Faecal microbiota transplant from aged donor mice affects spatial learning and memory via modulating hippocampal synaptic plasticity- and neurotransmission-related proteins in young recipients

Abstract Background The gut-brain axis and the intestinal microbiota are emerging as key players in health and disease. Shifts in intestinal microbiota composition affect a variety of systems; however, evidence of their direct impact on cognitive functions is still lacking. We tested whether faecal microbiota transplant (FMT) from aged donor mice into young adult recipients altered the hippocampus, an area of the central nervous system (CNS) known to be affected by the ageing process and related functions. Results Young adult mice were transplanted with the microbiota from either aged or age-matched donor mice. Following transplantation, characterization of the microbiotas and metabolomics profiles along with a battery of cognitive and behavioural tests were performed. Label-free quantitative proteomics was employed to monitor protein expression in the hippocampus of the recipients. We report that FMT from aged donors led to impaired spatial learning and memory in young adult recipients, whereas anxiety, explorative behaviour and locomotor activity remained unaffected. This was paralleled by altered expression of proteins involved in synaptic plasticity and neurotransmission in the hippocampus. Also, a strong reduction of bacteria associated with short-chain fatty acids (SCFAs) production (Lachnospiraceae, Faecalibaculum, and Ruminococcaceae) and disorders of the CNS (Prevotellaceae and Ruminococcaceae) was observed. Finally, the detrimental effect of FMT from aged donors on the CNS was confirmed by the observation that microglia cells of the hippocampus fimbria, acquired an ageing-like phenotype; on the contrary, gut permeability and levels of systemic and local (hippocampus) cytokines were not affected. Conclusion These results demonstrate that age-associated shifts of the microbiota have an impact on protein expression and key functions of the CNS. Furthermore, these results highlight the paramount importance of the gut-brain axis in ageing and provide a strong rationale to devise therapies aiming to restore a young-like microbiota to improve cognitive functions and the declining quality of life in the elderly. </jats:sec

Faecal microbiota transplant from aged donor mice affects spatial learning and memory via modulating hippocampal synaptic plasticity- and neurotransmission-related proteins in young recipients

AbstractBackgroundThe gut-brain axis and the intestinal microbiota are emerging as key players in health and disease. Shifts in intestinal microbiota composition affect a variety of systems, however, evidence of their direct impact on cognitive functions is still lacking. We tested whether faecal microbiota transplant (FMT) from aged donor mice into young adult recipients affected the hippocampus, an area of the central nervous system (CNS) known to be affected by the ageing process, and related functions.Methods and FindingsYoung adult mice were transplanted with the microbiota from either aged or age-matched donor mice. Following transplantation, characterization of the microbiotas and metabolomics profiles along with a battery of cognitive and behavioural tests were performed. Label-free quantitative proteomics was employed to monitor protein expression in the hippocampus of the recipients. Gut permeability, levels of circulating cytokines and expression of markers of microglia cells were also assessed. FMT from aged donors led to impaired spatial learning and memory in young adult recipients, whereas anxiety, explorative behaviour and locomotor activity remained unaffected. This was paralleled by altered expression of proteins involved in synaptic plasticity and neurotransmission in the hippocampus. Also, a strong reduction of bacteria associated with short-chain fatty acids (SCFAs) production (Lachnospiraceae, Faecalibaculum, and Ruminococcaceae) and disorders of the CNS (Prevotellaceae and Ruminococcaceae) was observed. Finally, microglia cells of the hippocampus fimbria, acquired an ageing-like phenotype, while gut permeability and levels of circulating cytokines remained unaffected.ConclusionsThese results demonstrate a direct effect of the age-associated shifts of the microbiota on protein expression and key functions of the central nervous system. Furthermore, these results additionally highlight the paramount importance of the gut-brain axis in ageing and provide a strong rationale to devise therapies aiming to restore a young-like microbiota to improve cognitive functions in the elderly.</jats:sec

A scuticociliate causes mass mortality of Diadema antillarum in the Caribbean Sea

Echinoderm mass mortality events shape marine ecosystems by altering the dynamics among major benthic groups. The sea urchin Diadema antillarum, virtually extirpated in the Caribbean in the early 1980s by an unknown cause, recently experienced another mass mortality beginning in January 2022. We investigated the cause of this mass mortality event through combined molecular biological and veterinary pathologic approaches comparing grossly normal and abnormal animals collected from 23 sites, representing locations that were either affected or unaffected at the time of sampling. Here, we report that a scuticociliate most similar to Philaster apodigitiformis was consistently associated with abnormal urchins at affected sites but was absent from unaffected sites. Experimentally challenging naïve urchins with a Philaster culture isolated from an abnormal, field-collected specimen resulted in gross signs consistent with those of the mortality event. The same ciliate was recovered from treated specimens postmortem, thus fulfilling Koch's postulates for this microorganism. We term this condition D. antillarum scuticociliatosis