Angular momentum generation in nuclear fission.

When a heavy atomic nucleus splits (fission), the resulting fragments are observed to emerge spinning1; this phenomenon has been a mystery in nuclear physics for over 40 years2,3. The internal generation of typically six or seven units of angular momentum in each fragment is particularly puzzling for systems that start with zero, or almost zero, spin. There are currently no experimental observations that enable decisive discrimination between the many competing theories for the mechanism that generates the angular momentum4-12. Nevertheless, the consensus is that excitation of collective vibrational modes generates the intrinsic spin before the nucleus splits (pre-scission). Here we show that there is no significant correlation between the spins of the fragment partners, which leads us to conclude that angular momentum in fission is actually generated after the nucleus splits (post-scission). We present comprehensive data showing that the average spin is strongly mass-dependent, varying in saw-tooth distributions. We observe no notable dependence of fragment spin on the mass or charge of the partner nucleus, confirming the uncorrelated post-scission nature of the spin mechanism. To explain these observations, we propose that the collective motion of nucleons in the ruptured neck of the fissioning system generates two independent torques, analogous to the snapping of an elastic band. A parameterization based on occupation of angular momentum states according to statistical theory describes the full range of experimental data well. This insight into the role of spin in nuclear fission is not only important for the fundamental understanding and theoretical description of fission, but also has consequences for the γ-ray heating problem in nuclear reactors13,14, for the study of the structure of neutron-rich isotopes15,16, and for the synthesis and stability of super-heavy elements17,18.

The vascular access questionnaire: a single centre UK experience.

BACKGROUND: Haemodialysis is capable of prolonging life in patients with end stage renal disease, however this therapy comes with significant negative impact on quality of life. For patients requiring haemodialysis, the need for an adequately functioning vascular access (VA) is an everyday concern. The Vascular Access Questionnaire (VAQ) provides a mechanism for identifying and scoring factors in haemodialysis that impact on patients' quality of life and perception of their therapy. METHODS: Between April 2017-18 the VAQ was administered to prevalent haemodialysis patients at 10 units in the West Midlands via structured interviews. RESULTS: 749 of 920 potentially eligible patients completed the survey. The mean VAQ score was seen to improve significantly with age (7.7 in < 55 vs. 3.8 in 75+) and the duration of access (8.9 if less than 1 month old vs. 5.0 at a year). Better average scores were demonstrated for Arteriovenous fistulas (AVF) than other modalities (AVF 5.1 vs. AVG (arteriovenous grafts) 7.2 vs. CVC (central venous catheter) 6.6). There was no significant difference in scores between fistulas on non-dominant or dominant arms, with both having a mean of 5.2 (p = 0.341). CONCLUSIONS: Overall, better satisfaction scores were seen in AVF. The presence of an AVF on the non-dominant arm was not a concern for the majority of patients and did not affect the VAQ score. A number of factors were identified that can influence VAQ satisfaction score.

Differential effects of exposure to parasites and bacteria on stress response in turbot Scophthalmus maximus simultaneously stressed by low water depth.

The stress response of turbot Scophthalmus maximus was evaluated in fish maintained 8 days under different water depths, normal (NWD, 30 cm depth, total water volume 40 l) or low (LWD, 5 cm depth, total water volume 10 l), in the additional presence of infection-infestation of two pathogens of this species. This was caused by intraperitoneal injection of sublethal doses of the bacterium Aeromonas salmonicida subsp. salmonicida or the parasite Philasterides dicentrarchi (Ciliophora:Scuticociliatida). The LWD conditions were stressful for fish, causing increased levels of cortisol in plasma, decreased levels of glycogen in liver and nicotinamide adenine dinucleotide phosphate (NADP) and increased activities of G6Pase and GSase. The presence of bacteria or parasites in fish under NWD resulted in increased cortisol levels in plasma whereas in liver, changes were of minor importance including decreased levels of lactate and GSase activity. The simultaneous presence of bacteria and parasites in fish under NWD resulted a sharp increase in the levels of cortisol in plasma and decreased levels of glucose. Decreased levels of glycogen and lactate and activities of GSase and glutathione reductase (GR), as well as increased activities of glucose-6-phosphate dehydrogenase (G6PDH), 6-phosphogluconate dehydrogenase (6PGDH) and levels of nicotinamide adenine dinucleotide phosphate (NADPH) occurred in the same fish in liver. Finally, the presence of pathogens in S. maximus under stressful conditions elicited by LWD resulted in synergistic actions of both type of stressors in cortisol levels. In liver, the presence of bacteria or parasites induced a synergistic action on several variables such as decreased activities of G6Pase and GSase as well as increased levels of NADP and NADPH and increased activities of GPase, G6PDH and 6PGDH.

Epigenetic biomarkers in progression from non-dysplastic Barrett's oesophagus to oesophageal adenocarcinoma: a systematic review protocol.

INTRODUCTION: Barrett's oesophagus (BO), a metaplastic condition affecting the lower oesophagus due to long-standing gastro-oesophageal reflux and chronic inflammation, is a precursor lesion for oesophageal adenocarcinoma (OADC). There is no clinical test to predict which patients with BO will progress to OADC. The British Society of Gastroenterology recommends endoscopic surveillance of patients with BO. Epigenetic changes have been well characterised in the neoplastic progression of ulcerative colitis to colonic carcinoma, another gastrointestinal cancer associated with chronic inflammation. This systematic review protocol aims to identify and evaluate studies which examine epigenetic biomarkers in BO and their association with progression to OADC. METHODS AND ANALYSIS: All prospective and retrospective primary studies, and existing systematic reviews investigating epigenetic markers including DNA methylation, histone modification, chromatin remodelling, micro and non-coding RNAs of all types will be eligible for inclusion. Eligible patients are those over the age of 18 with BO, BO with dysplasia, OADC or unspecified oesophageal cancer. A comprehensive search of bibliographic databases using combinations of text and index words relating to the population, prognostic markers and outcome will be undertaken with no language restrictions. Results will be screened by 2 independent reviewers and data extracted using a standardised proforma. The quality and risk of bias of individual studies will be assessed using the Quality in Prognostic Studies (QUIPS) tool. A narrative synthesis of all evidence will be performed with key findings tabulated. Meta-analysis will be considered where studies and reported outcomes are considered sufficiently homogeneous, both clinically and methodologically. Findings will be interpreted in the context of the quality of included studies. The systematic review will be reported according to PRISMA guidelines. ETHICS AND DISSEMINATION: This is a systematic review of completed studies and no ethical approval is required. Findings from the full systematic review will be submitted for publication and presentation at national and international conferences which will inform future research on risk stratification in patients with BO. REVIEW REGISTRATION NUMBER: CRD42016038654.

Two-Proton Radioactivity of

In an experiment with the BigRIPS separator at the RIKEN Nishina Center, we observed two-proton (2p) emission from ^{67}Kr. At the same time, no evidence for 2p emission of ^{59}Ge and ^{63}Se, two other potential candidates for this exotic radioactivity, could be observed. This observation is in line with Q value predictions which pointed to ^{67}Kr as being the best new candidate among the three for two-proton radioactivity. ^{67}Kr is only the fourth 2p ground-state emitter to be observed with a half-life of the order of a few milliseconds. The decay energy was determined to be 1690(17) keV, the 2p emission branching ratio is 37(14)%, and the half-life of ^{67}Kr is 7.4(30) ms.

Effective qPCR methodology to quantify the expression of virulence genes in Aeromonas salmonicida subsp. salmonicida.

AIMS: This study aimed to select and validate different methodological strategies to quantify the expression of the virulence genes ascC and ascV by qPCR in Aeromonas salmonicida subsp. salmonicida (Aer. salmonicida). METHODS AND RESULTS: Using the geNorm, Normfinder and BestKeeper algorithms, reference genes for the qPCR were selected based on their in vitro expression stabilities in three Aer. salmonicida strains. Gene amplification efficiency was calculated by Real-time PCR Miner and LinReg PCR programmes, which have not been used previously in the analysis of bacterial gene expression. The expression of the ascC and ascV virulence genes in a virulent Aer. salmonicida strain was evaluated by three quantification models, including single (least or most stable) or three most stable reference genes, combined with constant or specific gene amplification efficiency. The most stable reference genes were gyrB, proC and rpoC, while rpoD and fabD were the least stable. Quantification models showed different expression patterns. CONCLUSIONS: The optimal strategy to quantify mRNA expression was to use a combination of the three algorithms and the quantification model including the three most stable reference genes. Real-time PCR Miner or LinReg PCR were valuable tools to estimate amplification efficiency. SIGNIFICANCE AND IMPACT OF THE STUDY: The methods used in this study gave more reliable expression data using qPCR than previously published methods. The quantification and expression dynamics of virulence genes will contribute to a better understanding of how Aer. salmonicida interacts with its host and the environment, and therefore to the prevention of epizootics due to this pathogen.

Half-life systematics across the N=126 shell closure: role of first-forbidden transitions in the ß decay of heavy neutron-rich nuclei.

This Letter reports on a systematic study of ß-decay half-lives of neutron-rich nuclei around doubly magic (208)Pb. The lifetimes of the 126-neutron shell isotone (204)Pt and the neighboring (200-202)Ir, (203)Pt, (204)Au are presented together with other 19 half-lives measured during the "stopped beam" campaign of the rare isotope investigations at GSI collaboration. The results constrain the main nuclear theories used in calculations of r-process nucleosynthesis. Predictions based on a statistical macroscopic description of the first-forbidden ß strength reveal significant deviations for most of the nuclei with N<126. In contrast, theories including a fully microscopic treatment of allowed and first-forbidden transitions reproduce more satisfactorily the trend in the measured half-lives for the nuclei in this region, where the r-process pathway passes through during ß decay back to stability.

Observation of the ß-delayed γ-proton decay of (56)Zn and its impact on the Gamow-Teller strength evaluation.

We report the observation of a very exotic decay mode at the proton drip line, the ß-delayed γ-proton decay, clearly seen in the ß decay of the T_{z}=-2 nucleus ^{56}Zn. Three γ-proton sequences have been observed after the ß decay. Here this decay mode, already observed in the sd shell, is seen for the first time in the fp shell. Both γ and proton decays have been taken into account in the estimation of the Fermi and Gamow-Teller strengths. Evidence for fragmentation of the Fermi strength due to strong isospin mixing is found.

Virulence factors of Aeromonas salmonicida subsp. salmonicida strains associated with infections in turbot Psetta maxima.

Virulence factors for Aeromonas salmonicida subsp. salmonicida (ASS) strains isolated from cultured turbot Psetta maxima L. are unknown with regard to this host. The presence of virulence genes associated with different stages of ASS infection in salmonids (vapA, tapA, fla, ascV, ascC, aexT, satA and aspA) was analysed using a polymerase chain reaction (PCR) technique in ASS strains isolated from turbot. Other ASS strains isolated from salmonids and environmental A. salmonicida (AS) strains were included for comparison. The presence of the genes was evaluated with respect to ASS virulence in turbot based on intraperitoneal and bath challenges. The genetic profile, including all of the genes studied, that was linked to virulent behaviour after intraperitoneal challenge was significantly more frequent in strains isolated from turbot than in those from salmonids or the environment. The data prove that it is not possible to predict the virulence of ASS in turbot based only on the presence of all genes tested. Moreover, the combined PCR results of vapA, aexT, ascV and ascC were useful for separating most of the ASS from environmental A. salmonicida strains. An association between virulence or genetic profile and the geographical or facility origin of the strains was not found.

Direct observation of two protons in the decay of 54Zn.

The two protons emitted in the decay of 54Zn have been individually observed for the first time in a time projection chamber. The total decay energy and the half-life measured in this work agree with the results obtained in a previous experiment. Angular and energy correlations between the two protons are determined and compared to theoretical distributions of a three-body model. Within the shell model framework, the relative decay probabilities show a strong contribution of the p2 configuration for the two-proton emission. After 45Fe, the present result on 54Zn constitutes only the second case of a direct observation of the ground state two-proton decay of a long-lived isotope.

Colonization of turbot tissues by virulent and avirulent Aeromonas salmonicida subsp. salmonicida strains during infection.

Preventing disease outbreaks in cultured turbot Psetta maxima L. caused by Aeromonas salmonicida subsp. salmonicida (ASS) requires a better understanding of how this pathogen colonizes its host. Distribution of 1 virulent and 2 avirulent ASS strains in turbot tissues was investigated during early and late stages of infection following an immersion challenge. To track bacteria within the turbot, the ASS strains were tagged with green fluorescent protein (GFP). Both virulent and avirulent strains colonized the epidermal mucus, gills, and intestine within the first 12 h post challenge, suggesting that these sites may serve as points of entry into turbot. Although the avirulent strains colonized these initial sites in the turbot tissues, they were rarely found in the internal organs and were cleared from the host 4 d post challenge. In contrast, the virulent ASS strain was found in the liver and kidney as early as 12 h post challenge and was found in the muscle tissue at very late stages of infection. The virulent strain persisted in all tested host tissues until death occurred 7 d post challenge, suggesting that ASS must colonize and survive within the turbot tissues for an infection to result in death of the fish. Comparisons of the distribution profiles of both virulent and avirulent strains during early and late stages of an infection in turbot has provided important information on the route and persistence of an ASS infection in this host.

Coincidence measurement of residues and light particles in the reaction 56Fe+p at 1 GeV per nucleon with the spallation reactions setup SPALADIN.

The spallation of 56Fe in collisions with hydrogen at 1A GeV has been studied in inverse kinematics with the large-aperture setup SPALADIN at GSI. Coincidences of residues with low-center-of-mass kinetic energy light particles and fragments have been measured allowing the decomposition of the total reaction cross section into the different possible deexcitation channels. Detailed information on the evolution of these deexcitation channels with excitation energy has also been obtained. The comparison of the data with predictions of several deexcitation models coupled to the INCL4 intranuclear cascade model shows that only GEMINI can reasonably account for the bulk of collected results, indicating that in a light system with no compression and little angular momentum, multifragmentation might not be necessary to explain the data.

Presence of a lethal protease in the extracellular products of Vibrio splendidus-Vibrio lentus related strains.

The presence of a lethal extracellular 39-kDa protease, a virulence determinant of a Listonella pelagia strain which produces vibriosis in turbot, was determined in the extracellular products (ECP) of 33 Vibrionaceae strains. Both immunological and enzymatic techniques distinguished this specific protease from other Vibrionaceae proteins. It was detected in 15% (5/33) of the ECPs assayed belonging to strains of the Vibrio splendidus-V. lentus related group isolated in Galician aquaculture systems (NW Spain). As these strains were associated with diseased octopus and cultured turbot, were able to colonize the internal organs of fish and produced a lethal ECP for fish, they are a potential risk for the health of reared aquatic organisms.

Parálisis aguda del XII par craneal / Acute palsy of twelfth cranial nerve

La parálisis del nervio hipogloso o XII par craneal es una enfermedad infrecuente de forma aislada que puede ser debida a múltiples causas: Tumores o metástasis de la base del cráneo o del recorrido nervioso cervical, schwannoma del nervio, disección carotídea, traumatismo s cervicales, idiopática, radioterapia, infecciones (mononucleosis infecciosa) o neuropatías de diversa etiología. Presentamos un caso de parálisis aguda del hipogloso y realizamos el diagnóstico diferencial desde el punto de vista etiopatogénico y clínico

The hypoglossal nerve or Twelfth-nerve palsy is a rare damage with different causes: Tumors or metastases in skull base, cervicals tumors, schwannoma, dissection or aneurysm carotid arteries, stroke, trauma, idiopathic cause, radiation, infections (mononucleosis) or multiple cranial neuropathy. Tumors were responsible for nearly half of the cases in different studies. We studied a female with hypoglossal nerve acute palsy. We made a differential diagnostic with others causes and a review of the literature

[Acute palsy of twelfth cranial nerve]. / Parálisis aguda del XII par craneal.

The hypoglossal nerve or Twelfth-nerve palsy is a rare damage with different causes: tumors or metastases in skull base, cervicals tumors, schwannoma, dissection or aneurysm carotid arteries, stroke, trauma, idiopathic cause, radiation, infections (mononucleosis) or multiple cranial neuropathy. Tumors were responsible for nearly half of the cases in different studies. We studied a female with hypoglossal nerve acute palsy. We made a differential diagnostic with others causes and a review of the literature.

Characterization of Vibrio strains isolated from turbot (Scophthalmus maximus) culture by phenotypic analysis, ribotyping and 16S rRNA gene sequence comparison.

AIM: The aim of the present study was to clarify the taxonomic status of Vibrio strains isolated from an aquaculture system and to compare the results of the identifications made by phenotypic and molecular methods. METHODS AND RESULTS: Fifty-one Vibrio strains isolated from a turbot (Scophthalmus maximus) aquaculture system were characterized by ribotyping and 16S rRNA gene sequencing. The strains had been identified phenotypically in a previous numerical taxonomy analysis as Vibrio anguillarum, V. mediterranei, V. splendidus, V. aestuarianus, V. ordalii, V. fischeri and V. scophthalmi. Cluster analysis of ribotype patterns showed that the strains were separated into two main groups: V. splendidus-V. lentus and V. scophthalmi groups. The use of 16S rRNA gene sequence allowed differentiation among V. splendidus biovar I and V. lentus strains. CONCLUSIONS: The molecular methods identified strains of V. splendidus biovar I, V. lentus and V. scophthalmi, showing discrepancies with phenotypic characterization. SIGNIFICANCE AND IMPACT OF THE STUDY: The molecular methods, as 16S rRNA gene sequence analysis, are necessary for the identification of phenotypically close species to avoid mis-identifications. Interestingly, this is the first report of V. lentus strains associated to turbot culture.

Vibrio lentus associated with diseased wild octopus (Octopus vulgaris).

Studies were undertaken to identify the bacteria involved in a disease of wild octopus (Octopus vulgaris). Signs of the disease include round hard lesions in the arms or head mantle, leading, in advanced cases, to the loss of skin and the exposure of the muscle beneath. Bacterial strains isolated from sterile organs have been evaluated taxonomically and by experimental infections. Different phenotypes and ribotypes of Vibrio lentus were identified. Experimental infection by bath challenge demonstrated that V. lentus was able to reproduce the skin lesions, colonize the internal organs and induce mortality in healthy octopuses. V. lentus was re-isolated from the skin lesions and gill heart of dead octopuses, as confirmed by numerical taxonomy analysis. No effects were produced in sea bream or turbot by intraperitoneal injection of the bacterial isolate.

Purification and partial characterisation of a fish lethal extracellular protease from Vibrio pelagius.

The purification, characterisation and lethal effect of an extracellular protease present in the extracellular products (ECPs) of a pathogenic Vibrio pelagius (7P) strain are described. The extracellular protease was purified by size-exclusion high-performance liquid chromatography and characterised by enzymatic assays. The lethal effect was evaluated by injection into fish. The native protease had a molecular mass of 39 kDa, was active on casein and L-leucyl-beta-naphthylamide (LNA) and its metalloprotease nature was shown by the LNA inhibition profile. Kinetic studies on the hydrolysis of casein and LNA confirmed a competitive inhibition of one substrate with respect to the other. The temperature assays showed that both aminopeptidolytic and caseinolytic activities were labile at 70 degrees C for 3 min. The N-terminal amino acid sequence of 7P protease revealed a high degree of homology with other metalloproteases of Vibrio species that are implicated in virulence. The purified 7P protease showed an LD(50) of 1.77 microgprotein/g fish for turbot. The quick lethal effect (<24h) and the macroscopic damage (external haemorrhagic areas, principally on fins and mouth, petechial haemorrhages in internal organs, but with no external or internal apparent necrotic areas) detected in the host were similar to those obtained by injection of total ECP and live cells of 7P strain. An extracellular protease with endopeptidolytic and exopeptidolytic activities, responsible for the lethal effect of ECP and clinical signs of vibriosis in turbot was purified from a pathogenic V. pelagius (7P) strain.

A 45-kDa acetylcholinesterase protoxin of Aeromonas hydrophila: purification and immunogenicity in fish.

A rabbit antiserum to the 15-kDa acetylcholinesterase toxin neutralised the lethal effect of the 15-kDa toxin of Aeromonas hydrophila when injected into trout. However, immunisation of fish with the 15-kDa toxoid failed to induce an antibody response, and a higher molecular mass form of this toxin was purified from the extracellular products with the aim of inducing an immune response in fish. The optimal conditions for production of extracellular products by A. hydrophila strain B32 were studied to increase the concentration of this protoxin. The extracellular products were fractionated by molecular exclusion chromatography to yield a purified protoxin with an estimated molecular mass of 45 kDa by SDS-PAGE and which gave a positive reaction in Western blotting with the rabbit anti-15-kDa toxin serum. Since the 45-kDa protoxin showed lower specific acetylcholinesterase activity than the active 15-kDa toxin, the behaviour of the active site was studied using specific inhibitors. This 45-kDa protoxin was 13.3-fold less toxic than the 15-kDa toxin and induced antibody production in fish.