Novel α + β Zr Alloys with Enhanced Strength

Low-alloyed zirconium alloys are widely used in nuclear applications due to their low neutron absorption cross-section. These alloys, however, suffer from limited strength. Well-established guidelines for the development of Ti alloys were applied to design new two-phase ternary Zr alloys with improved mechanical properties. Zr-4Sn-4Nb and Zr-8Sn-4Nb alloys have been manufactured by vacuum arc melting, thermo-mechanically processed by annealing, forging, and aging to various microstructural conditions and thoroughly characterized. Detailed Scanning electron microscopy (SEM) analysis showed that the microstructural response of the alloys is rather similar to alpha + beta Ti alloys. Duplex microstructure containing primary alpha phase particles surrounded by lamellar alpha + beta microstructure can be achieved by thermal processing. Mechanical properties strongly depend on the previous treatment. Ultimate tensile strength exceeding 700 MPa was achieved exceeding the strength of commercial Zr alloys for nuclear applications by more than 50%. Such an improvement in strength more than compensates for the increased neutron absorption cross-section. This study aims to exploit the potential of alpha + beta Zr alloys for nuclear applications.     

Subnuclear partitioning of rRNA genes between the nucleolus and nucleoplasm reflects alternative epiallelic states

Eukaryotes can have thousands of 45S ribosomal RNA (rRNA) genes, many of which are silenced during development. Using fluorescence-activated sorting techniques, we show that active rRNA genes in Arabidopsis thaliana are present within sorted nucleoli, whereas silenced rRNA genes are excluded. DNA methyltransferase (met1), histone deacetylase (hda6), or chromatin assembly (caf1) mutants that disrupt silencing abrogate this nucleoplasmic–nucleolar partitioning. Bisulfite sequencing data indicate that active nucleolar rRNA genes are nearly completely demethylated at promoter CGs, whereas silenced genes are nearly fully methylated. Collectively, the data reveal that rRNA genes occupy distinct but changeable nuclear territories according to their epigenetic state.     

Presence of different genotypes of Helicobacter pylori in patients with chronic tonsillitis and sleep apnoea syndrome

Helicobacter pylori, a well-known gastric pathogen, has been detected in the oral cavity and oropharynx in tonsillar tissue. In our study, the presence of H. pylori in the tonsillar tissue of patients with chronic tonsillitis and sleep apnoea syndrome (SAS) was investigated. The aim was to detect and genotype H. pylori for a collection of data supporting the possible role of H. pylori in the aetiology of chronic tonsillitis and SAS. Helicobacter pylori was detected by real-time polymerase chain reaction (rt-PCR). 89 patients, 60 with a diagnosis of chronic tonsillitis and 29 with SAS, were tested. In the chronic tonsillitis group, Helicobacter was detected in 48 (80 %) specimens, cagA gene was detected in 12 samples (25 %) and 12 samples were negative. In SAS group, Helicobacter was found in 24 samples (82.76 %), cagA gene was detected in 5 (20.83 %) and 5 samples (17.24 %) were negative. Helicobacter pylori-specific immunoglobulins were tested by ELISA in the serum of 57 patients only with 41 (71.93 %) showing positive. Our results on H. pylori DNA detection and H. pylori seropositivity show 26.32 % discrepancy, slightly in favour of rt-PCR (15.79 % compared to 10.53 %). The H. pylori presence in tonsillar tissue does not depend on the type of oropharyngeal disease (p = 0.756). This study shows that oropharynx constitutes an extragastric reservoir of H. pylori infection which could serve as an aetiopathogenetic factor for chronic tonsillitis and tonsillar hyperplasia by SAS. No conclusion has yet been drawn about the mechanism of the process.     

Genomewide profiling of copy‐number alteration in monoclonal gammopathy of undetermined significance

Monoclonal gammopathy of undetermined significance (MGUS) is a benign condition with an approximate 1% annual risk of symptomatic plasma cell disorder development, mostly to multiple myeloma (MM). We performed genomewide screening of copy‐number alterations (CNAs) in 90 MGUS and 33 MM patients using high‐density DNA microarrays. We identified CNAs in a smaller proportion of MGUS (65.6%) than in MM (100.0%, P = 1.31 × 10^?5) and showed median number of CNAs is lower in MGUS (3, range 0–22) than in MM (13, range 4–38, P = 1.82 × 10^?10). In the MGUS cohort, the most frequent losses were located at 1p (5.6%), 6q (6.7%), 13q (30.0%), 14q (14.4%), 16q (8.9%), 21q (5.6%), and gains at 1q (23.3%), 2p (6.7%), 6p (13.3%), and Xq (7.8%). Hyperdiploidy was detected in 38.9% of MGUS cases, and the most frequent whole chromosome gains were 3 (25.6%), 5 (23.3%), 9 (37.8%), 15 (23.3%), and 19 (32.2%). We also identified CNAs such as 1p, 6q, 8p, 12p, 13q, 16q losses, 1q gain and hypodiploidy, which are potentially associated with an adverse prognosis in MGUS. In summary, we showed that MGUS is similar to MM in that it is a genetically heterogeneous disorder, but overall cytogenetic instability is lower than in MM, which confirms that genetic abnormalities play important role in monoclonal gammopathies.     

Molecular characterization and phylogeny of whipworm nematodes inferred from DNA sequences of cox1 mtDNA and 18S rDNA

A molecular phylogenetic hypothesis is presented for the genus Trichuris based on sequence data from the mitochondrial cytochrome c oxidase 1 (cox1) and ribosomal 18S genes. The taxa consisted of different described species and several host-associated isolates (undescribed taxa) of Trichuris collected from hosts from Spain. Sequence data from mitochondrial cox1 (partial gene) and nuclear 18S near-complete gene were analyzed by maximum likelihood and Bayesian inference methods, as separate and combined datasets, to evaluate phylogenetic relationships among taxa. Phylogenetic results based on 18S ribosomal DNA (rDNA) were robust for relationships among species; cox1 sequences delimited species and revealed phylogeographic variation, but most relationships among Trichuris species were poorly resolved by mitochondrial sequences. The phylogenetic hypotheses for both genes strongly supported monophyly of Trichuris, and distinct genetic lineages corresponding to described species or nematodes associated with certain hosts were recognized based on cox1 sequences. Phylogenetic reconstructions based on concatenated sequences of the two loci, cox1 (mitochondrial DNA (mtDNA)) and 18S rDNA, were congruent with the overall topology inferred from 18S and previously published results based on internal transcribed spacer sequences. Our results demonstrate that the 18S rDNA and cox1 mtDNA genes provide resolution at different levels, but together resolve relationships among geographic populations and species in the genus Trichuris.     

Acute coronary syndromes with ongoing myocardial ischemia (ACS with OMI) versus acute coronary syndromes without ongoing ischemia (ACS without OMI): The new classification of acute coronary syndromes should replace old classification based on ST segment elevation presence or absence—Expert consensus statement of the Czech Society of Cardiology

The Czech Society of Cardiology is proposing here the new classification of acute coronary syndromes at the time of the first medical contact. The proposal suggests to remove the terms “ST elevation myocardial infarction” and “non-ST elevation acute coronary syndrome” and to replace these terms by “acute coronary syndrome with ongoing myocardial ischemia” and “acute coronary syndrome without ongoing myocardial ischemia”. The proposed new classification better reflects current treatment approaches and will facilitate the decision making at the first medical contact.