Submillisievert chest CT in patients with COVID-19 - experiences of a German Level-I center

Purpose: Computed tomography (CT) is used for initial diagnosis and therapy monitoring of patients with coronavirus disease 2019 (COVID-19). As patients of all ages are affected, radiation dose is a concern. While follow-up CT examinations lead to high cumulative radiation doses, the ALARA principle states that the applied dose should be as low as possible while maintaining adequate image quality. The aim of this study was to evaluate parameter settings for two commonly used CT scanners to ensure sufficient image quality/diagnostic confidence at a submillisievert dose. Materials and methods: We retrospectively analyzed 36 proven COVID-19 cases examined on two different scanners. Image quality was evaluated objectively as signal-to-noise ratio (SNR)/contrast-to-noise ratio (CNR) measurement and subjectively by two experienced, independent readers using 3-point Likert scales. CT dose index volume (CTDIvol) and dose-length product (DLP) were extracted from dose reports, and effective dose was calculated. Results: With the tested parameter settings we achieved effective doses below 1 mSv (median 0.5 mSv, IQR: 0.2 mSv, range: 0.3−0.9 mSv) in all 36 patients. Thirty-four patients had typical COVID-19 findings. Both readers were confident regarding the typical COVID-19 CT-characteristics in all cases (3 ± 0). Objective image quality parameters were: SNRnormal lung: 17.0 ± 5.9, CNRGGO/normal lung: 7.5 ± 5.0, and CNRconsolidation/normal lung: 15.3 ± 6.1. Conclusion: With the tested parameters, we achieved applied doses in the submillisievert range, on two different CT scanners without sacrificing diagnostic confidence regarding COVID-19 findings

Inflammatory Bowel Diseases Phenotype, C. difficile and NOD2 Genotype Are Associated with Shifts in Human Ileum Associated Microbial Composition

We tested the hypothesis that Crohn’s disease (CD)-related genetic polymorphisms involved in host innate immunity are associated with shifts in human ileum–associated microbial composition in a cross-sectional analysis of human ileal samples. Sanger sequencing of the bacterial 16S ribosomal RNA (rRNA) gene and 454 sequencing of 16S rRNA gene hypervariable regions (V1–V3 and V3–V5), were conducted on macroscopically disease-unaffected ileal biopsies collected from 52 ileal CD, 58 ulcerative colitis and 60 control patients without inflammatory bowel diseases (IBD) undergoing initial surgical resection. These subjects also were genotyped for the three major NOD2 risk alleles (Leu1007fs, R708W, G908R) and the ATG16L1 risk allele (T300A). The samples were linked to clinical metadata, including body mass index, smoking status and Clostridia difficile infection. The sequences were classified into seven phyla/subphyla categories using the Naïve Bayesian Classifier of the Ribosome Database Project. Centered log ratio transformation of six predominant categories was included as the dependent variable in the permutation based MANCOVA for the overall composition with stepwise variable selection. Polymerase chain reaction (PCR) assays were conducted to measure the relative frequencies of the Clostridium coccoides – Eubacterium rectales group and the Faecalibacterium prausnitzii spp. Empiric logit transformations of the relative frequencies of these two microbial groups were included in permutation-based ANCOVA. Regardless of sequencing method, IBD phenotype, Clostridia difficile and NOD2 genotype were selected as associated (FDR ≤0.05) with shifts in overall microbial composition. IBD phenotype and NOD2 genotype were also selected as associated with shifts in the relative frequency of the C. coccoides – E. rectales group. IBD phenotype, smoking and IBD medications were selected as associated with shifts in the relative frequency of F. prausnitzii spp. These results indicate that the effects of genetic and environmental factors on IBD are mediated at least in part by the enteric microbiota

Disease phenotype and genotype are associated with shifts in intestinal-associated microbiota in inflammatory bowel diseases:

Abnormal host-microbe interactions are implicated in the pathogenesis of inflammatory bowel diseases. Previous 16S rRNA sequence analysis of intestinal tissues demonstrated that a subset of Crohn’s disease (CD) and ulcerative colitis (UC) samples exhibited altered intestinal associated microbial compositions characterized by depletion of Bacteroidetes and Firmicutes (particularly Clostridium taxa). We hypothesize that NOD2 and ATG16L1 risk alleles may be associated with these alterations

Microwave synthesis and magnetic properties of Laves-type Ti2M3Si (M = Mn, Fe, Co, Ni)

International audienceFast and energy-efficient synthesis methods become increasingly important aspects in the experimental high throughput searching of functional materials. Particularly high-temperature solid-state preparation techniques typically require large amounts of energy due to extended heating cycles. Therefore, we have utilized a time and energy-efficient synthesis method using a commercial microwave oven in order to prepare intermetallic Laves-type phases. Ti2M3Si withM = Mn, Fe, Co, Ni can be prepared within only 10min of microwave heating based on this convenient one-step procedure. These compounds are of interest because of their potentially useful magnetic properties and therefore contribute to the ongoing search for rare earth-free alternatives to state-of-the-art magnetic materials

Microwave synthesis and magnetic properties of Laves-type Ti2M3Si (M = Mn, Fe, Co, Ni)

Fast and energy-efficient synthesis methods become increasingly important aspects in the experimental high throughput searching of functional materials. Particularly high-temperature solid-state preparation techniques typically require large amounts of energy due to extended heating cycles. Therefore, we have utilized a time and energy-efficient synthesis method using a commercial microwave oven in order to prepare intermetallic Laves-type phases. Ti2M3Si with M = Mn, Fe, Co, Ni can be prepared within only 10 min of microwave heating based on this convenient one-step procedure. These compounds are of interest because of their potentially useful magnetic properties and therefore contribute to the ongoing search for rare earth-free alternatives to state-of-the-art magnetic materials.Transition metal-based Laves phase compounds Ti2M3Si were prepared by time- and energy-efficient microwave heating and their structural and magnetic properties studied

Microwave synthesis and magnetic properties of Laves-type Ti2M3Si (M = Mn, Fe, Co, Ni)

International audienceFast and energy-efficient synthesis methods become increasingly important aspects in the experimental high throughput searching of functional materials. Particularly high-temperature solid-state preparation techniques typically require large amounts of energy due to extended heating cycles. Therefore, we have utilized a time and energy-efficient synthesis method using a commercial microwave oven in order to prepare intermetallic Laves-type phases. Ti2M3Si withM = Mn, Fe, Co, Ni can be prepared within only 10min of microwave heating based on this convenient one-step procedure. These compounds are of interest because of their potentially useful magnetic properties and therefore contribute to the ongoing search for rare earth-free alternatives to state-of-the-art magnetic materials

Non-conventional synthesis and magnetic properties of MAX phases (Cr/Mn)2AlC and (Cr/Fe)2AlC

A few years after the theoretical prediction of magnetic MAX phases, a number of such materials have been experimentally reported, especially in the form of thin films. Yet, due to a relatively small number of studies, we have only just begun to discover the intriguing magnetic properties that are associated with this class of materials. The preparation of bulk MAX phases with later transition metals has been proven to be particularly challenging. Consequentially, there is a great need to develop synthetic strategies to obtain the respective materials in suitable quantities for magnetic investigations. Here, bulk Mn- and Fe-substituted Cr2AlC are prepared using non-conventional synthesis methods such as microwave heating and spark plasma sintering. Synchrotron X-ray diffraction coupled with detailed elemental analyses is used to confirm the successful doping of the MAX phase with the later transition metals as well as to elucidate the microstructure of the obtained dense materials. 57Fe Mössbauer spectroscopy data are presented showing signals of the doped MAX phase and Fe-containing secondary phases. Based on PPMS and SQUID measurements the non-trivial magnetic behavior of the obtained samples is discussed in the context of the existing studies