Atmospheric neutrinos from charm

Using next-to-leading order perturbative QCD, we find that the charm contribution to the atmospheric lepton fluxes dominates over the conventional ones from pi and K decays for energies higher than 10^5 GeV. We also discuss theoretical uncertainties involved in the calculations and compare our results with previous evaluations.Comment: 5 pages, 1 figure, submitted to the Proceedings of the International Workshop on Particle Physics and the Early Universe (COSMO-98), ed. David Caldwell, Asilomar, Monterey, California, November 15-20, 199

GaAs(110) surface electronic structure by metastable deexcitation spectroscopy

Metastable deexcitation spectroscopy was applied to study the surface valence electronic structure of clean cleaved GaAs(110). Metastable deexcitation spectroscopy was flanked by angle-resolved photoemission. An effective surface density of states was derived from the experimental spectrum through deconvolution. Two groups of states were observed in the 0-4 and 5-8 eV range of binding energy, respectively. These features were ascribed to emission from surface states. A plane-by-plane tight-binding density-of-states calculation was performed. More quantitative insights were obtained by comparing experimental and theoretical results. The most prominent feature of the first group of states of deconvolution was assigned to surface state A(5). Contributions from states A(4), A(3), A(1)', and A(2)' were also observed. The doublet of the second group of features was identified with C-2 and C-1. Relative amplitudes of effective surface density of states were related to surface charge density

Editorial: Integrating Whole Genome Sequencing Into Source Attribution and Risk Assessment of Foodborne Bacterial Pathogens

Source attribution and microbial risk assessment have proved to be crucial to identify and prioritize food safety interventions as to effectively control the burden of human illnesses (Cassini et al., 2016; Mughini-Gras et al., 2018a, 2019). By comparing human cases and pathogen occurrences in selected animal, food, and environmental sources, microbial subtyping approaches were successfully applied to pinpoint the most important sources of Salmonella, Campylobacter, Shiga toxin-producing Escherichia coli, and Listeria monocytogenes (Hald et al., 2004; Mullner et al., 2009a,b; Barco et al., 2013; Nielsen et al., 2017; Mughini-Gras et al., 2018b; Cody et al., 2019). Microbial risk assessment has been applied to assess known or potential adverse health effects resulting from human exposure to food-borne hazards. Through a scientific structured approach (FAO and WHO, 2021), microbial risk assessment helps to identify and quantify the risk represented by specific foods and the critical points in these foods' production chains for microbial control (Cassini et al., 2016; FAO and WHO, 2021). For both source attribution and risk assessment, one key challenge has been to define the hazard in question: is the whole foodborne pathogen species a hazard, or only some of its subtypes? In this regard the choice of the subtyping method becomes crucial. In recent years, Whole Genome Sequencing (WGS) has represented a major benefit for more targeted approaches, no longer focused on the species/genus level but at the level of subtypes (Franz et al., 2016; Fritsch et al., 2018; EFSA Panel on Biological Hazards, 2019). Besides WGS, metagenomics showed potentialities in source attribution. In particular, this approach was useful in attributing the source of environmental contamination by comparing the abundances of source-specific genetic markers (i.e., resistome) in different reservoirs (Gupta et al., 2019). Therefore, this special issue focuses on traditional and novel source attribution approaches applied on molecular, WGS, and metagenomic data as well as on a fine-tuning genetic characterization of foodborne pathogens useful for hazard identification and characterization. In particular, one study compares the outputs of a modified Hald model, which was applied to different subtyping input data of S. enterica Typhimurium and its monophasic variant (Arnold et al.) whereas two studies proposed a novel network approach and a method based on the core-genome genetic distance to attribute human infections of S. enterica Typhimurium monophasic variant and S. enterica Derby using WGS as input data (Merlotti et al.; Sévellec et al.). Another study by Duarte et al. included the relative abundance of antimicrobial resistance (AMR) associated genes (resistome) as metagenomic input data in an AMR source attribution study. Finally, two studies were focused on the molecular and genomic characterization of human isolates of Campylobacter jejuni and C. coli from China and of Listeria monocytogenes isolates collected from ready-to-eat meat and processing environment from Poland (Zhang et al.; Kurpas et al.). Arnold et al. performed a source attribution study including the genomes of S. enterica Typhimurium and its monophasic variant of 596 human sources and 327 animal sources from England and Wales between 2014 and 2016. Data from Seven Loci Multi Locus Sequence Typing (7-loci MLST), core-genome MLST (cg-MLST), and SNP calling were compared as input data. By applying a modified Hald model, 60% of human genomes were attributed to pork. Comparing different input data, results highlighted MLST as the method with the lowest fit and the lowest discriminatory power. Merlotti et al. applied a network approach to 351 human and animal genomes of S. enterica Typhimurium and its monophasic variant collected from 2013 to 2014. Three datasets of whole-genome MLST (wgMLST), cgMLST, and SNPs were used as input data. Genomes were clustered based on their genetic similarities. Interestingly, a higher percentage of cluster coherence was reported for animal sources in comparison to country and year of isolation, suggesting animal sources as the major driver of cluster formation. The approach showed to be effective in attributing up to 97.2% of human genomes to animal sources represented in the dataset. Among these genomes, the majority (84%) was attributed to pigs/pork. No significant differences were highlighted by comparing the three different input datasets. Core genome analysis was the approach applied by Sévellec et al. to attribute human sporadic cases of S. enterica Derby that occurred in France in 2014–2015 to non-human reservoirs. The authors analyzed 299 S. enterica Derby genomes corresponding to all S. enterica Derby sporadic human cases registered in the time frame, along with 141 non-human genomes. Within the non-human genomes, three main genomic lineages were detected in France: ST39-ST40 and ST682 associated to pork and ST71 associated to poultry. Within human genomes, 94% of S. enterica Derby clustered within the three genetic groups associated with pork, identifying this animal reservoir as the major contributor of S. enterica Derby to sporadic human cases in France. Relative abundance of antimicrobial resistance genes in shotgun metagenomic data was chosen in an antimicrobial resistance source attribution study by Duarte et al.. Starting from the assumption that fecal resistomes are source related, authors compared the resistomes of pooled fecal samples of pigs, broilers, turkeys, and veal calves with the resistomes of individual fecal samples of humans occupationally exposed to livestock production. Five supervised random forest models were applied on a total of 479 observations. Among the four livestock species, the results indicated that pigs have the resistome composition closest to the composition of the human resistome suggesting that occupational exposure to AMR determinants was higher among workers exposed to pigs than workers of broiler farms. Zhang et al. characterized genetic diversity and antimicrobial resistance of 236 Campylobacter jejuni and C. coli isolates collected from 2,945 individual stool samples of hospitalized patients with diarrhea in Beijing from 2017 to 2018. MLST results confirmed the high genetic diversity among isolates as well as CC21 as the most common clonal complex of C. jejuni in diarrhea patients in China. Clonal complex CC828 was the most frequently identified among C. coli isolates. Regarding antimicrobial resistance, rates higher than 88% were identified for the antimicrobials nalidixic acid, ciprofloxacin, and tetracycline. Last but not least, Kurpas et al. genetically characterized 48 L. monocytogenes isolates of PCR-serogroup IIb and IVb collected from ready-to-eat food and food processing environments. Additionally, the authors compared them with public genomes collected from humans in Poland. Among food isolates, 65% belonged to CC1, CC2, and CC6 already described as hypervirulent strains in humans. The clonal complex CC5 was also identified; mostly collected from food processing environments and belonging to PCR-serogroup IIB. Genomes of this clonal complex showed mutations in the inlA gene and a deletion of 144 bp in the inlB gene suggesting them as hypovirulent. Based on these studies, we conclude that the application of NGS data, in particular source attribution models, shows great potential. The results are improved by becoming more specific and to the point, which is considered very valuable for the decision support process. Integrations with phenotypic tests will continue to be essential for confirmation of NGS predicted outcomes

Cu-catalyzed Si-NWS grown on “carbon paper” as anodes for Li-ion cells

The very high theoretical capacity of the silicon (4200mAh/g more than 10 times larger than graphite), environmental-friendly, abundant and low-cost, makes it a potential candidate to replace graphite in high energy density Li-ion batteries. As a drawback, silicon suffers from huge volume changes (300%) on alloying and dealloying with Li, leading a structural deformation that induces disruption. The use of nanostructured silicon materials has been shown to be an effective way to avoid this mechanical degradation of the active material. In this paper the synthesis of silicon nanowires, grown on a highly porous 3D-like carbon paper substrate by CVD using Cu as the catalyst, is presented. The use of carbon paper allows to achieve remarkable loadings of active material (2-5 mg/cm2) and, consequently, high capacity densities. The silicon electrode was investigated both morphologically and electrochemically. To improve the electrochemical performance various strategies have been carried out. It was observed that a very slow first cycle (C/40), which helps the formation of a stable solid electrolyte interphase on the silicon surface, improves the performance of the cells; nevertheless, their cycle life has been found not fully satisfactory. Morphological analysis of the Si-NWs electrodes before and after cycling showed the presence of a dense silicon layer below the nanowires which could reduce the electrical contact between the active material and the substrate

Estudo estrutural e funcional do gene VvAGL11 e seu papel na morfogênese de sementes de Vitis vinifera.

O objetivo deste trabalho foi caracterizar estruturalmente a sequência codificadora de VvAGL11 e avaliar sua funcionalidade na morfogênese de sementes, por meio da complementação do mutante 'Seedstick' (stk) de Arabidopsis thaliana

Conformation, Stereodynamics, and Chiral Separation of the Rotational Enantiomers of Hindered Naphthyl Ketones.

A no. of α-naphthyl ketones bearing a Me group in the 2-position of the naphthalene ring adopt a twisted conformation, yielding a pair of rotational enantiomers owing to the restricted rotation about the naphthalene-carbonyl bond. NOE measurements indicate that the twisted conformation is almost exactly orthogonal. The enantiomerization barriers were detd. by variable-temp. dynamic NMR spectroscopy, with monitoring of either the anisochronous signals of prochiral substituents or the pairs of signals of the enantiomers themselves, made detectable at low temp. by the addn. of a chiral auxiliary agent. The free energies of activation cover a range of 8-20 kcal mol-1, depending on the steric hindrance of the various acyl groups. Mol. mechanics calcns. suggest that enantiomerization occurs through a pathway where the carbonyl function passes position 2, rather than position 8, of the naphthalene ring. In the case of a 1,5-disubstituted acyl deriv. contg. the tert-Bu moiety (I), the expected meso and racemic conformers were both obsd. in soln., whereas only the meso structure was present in the crystals (obtained by the usual slow crystn. procedure) as judged by CP MAS solid-state NMR spectra and by low-temp. soln. spectra in nonequil. conditions. Low-temp. (-15°) chiral high-performance liq. chromatog. (LT-ChirHPLC) was employed to sep., identify, and det. the yields of the two enantiomers of 2-methyl-1-naphthyl tert-Bu ketone (II) as well as the three conformers (meso, SS, and RR) of I. The low-temp. CD spectra of the rotational enantiomers of II and I were obtained and the abs. configurations assigned by connecting online a CD spectrometer to the LT-ChirHPLC app. Resp., the S and SS configurations were found to correspond to the conformational enantiomers with the shorter retention times [(R,R)-DAC-DNB column]

Novel deletions causing pseudoxanthoma elasticum underscore the genomic instability of the ABCC6 region

Mutations in ABCC6 cause pseudoxanthoma elasticum (PXE), a heritable disease that affects elastic fibers. Thus far, >200 mutations have been characterized by various PCR-based techniques (primarily direct sequencing), identifying up to 90% of PXE-causing alleles. This study wanted to assess the importance of deletions and insertions in the ABCC6 genomic region, which is known to have a high recombinational potential. To detect ABCC6 deletions/insertions, which can be missed by direct sequencing, multiplex ligation-dependent probe amplification (MLPA) was applied in PXE patients with an incomplete genotype. MLPA was performed in 35 PXE patients with at least one unidentified mutant allele after exonic sequencing and exclusion of the recurrent exon 23-29 deletion. Six multi-exon deletions and four single-exon deletions were detected. Using MLPA in addition to sequencing, we expanded the ABCC6 mutation spectrum with 9 novel deletions and characterized 25% of unidentified disease alleles. Our results further illustrate the instability of the ABCC6 genomic region and stress the importance of screening for deletions in the molecular diagnosis of PXE. Journal of Human Genetics (2010) 55, 112-117; doi: 10.1038/jhg.2009.132; published online 15 January 201

Time measurements by means of digital sampling techniques: a study case of 100 ps FWHM time resolution with a 100 MSample/s, 12 bit digitizer

Abstract An application of digital sampling techniques is presented which can simplify experiments involving sub-nanosecond time-mark determinations and energy measurements with nuclear detectors, used for Pulse Shape Analysis and Time of Flight measurements in heavy ion experiments. The basic principles of the method are discussed as well as the main parameters that influence the accuracy of the measurements. The method allows to obtain both time and amplitude information with an electronic chain simply consisting of a charge preamplifier and a fast high resolution ADC (in the present application: 100 MSample/s , 12 bit ) coupled to an efficient on-line software. In particular an accurate Time of Flight information can be obtained by mixing a beam related time signal with the output of the preamplifier. Examples of this technique applied to Silicon detectors in heavy-ions experiments involving particle identification via Pulse Shape analysis and Time of Flight measurements are presented. The system is suited for applications to large detector arrays and to different kinds of detectors

Pancreatic solid pseudopapillary neoplasm in male patients: systematic review with three new cases

Pancreatic solid pseudopapillary neoplasm (pSPN) is a rare exocrine neoplasm, which generally occurs in young women. This study analyses the clinical characteristics of pSPN in male patients through a systematic review of the literature, adding three new cases from our institution. We reviewed our experience in Pspns, and we performed a systematic review of pSPN of all articles published in English in PubMed and SCOPUS from 1980. Using the final included articles, we evaluated clinic-pathological features, surgical treatment and prognosis of male patients affected by pSPN. From the literature review and our cases, we collected 246 male patients with a proven pSPN. Mean age was 34.3 (range 4\u201378) years, with 26.2% patients younger than 18\ua0years. Patients were asymptomatic in 35.9% of cases, despite a mean tumour size of 6.3\ua0cm. In 63.7% of cases, the pSPN was located in the body\u2013tail region. Distant metastases were reported at diagnosis in only 10 (4.1%) patients. A correct pre-operative diagnosis (including cytopathology) was provided in 53.6% of patients, with only 40 fine-needle aspiration/biopsy performed. Standard pancreatic resections represented 90.4% of surgical procedures. Beta-catenin and progesterone receptors were positive at immunostaining in 100% and 77.8% of cases, respectively. Fourteen (7.2%) patients relapsed after a mean disease-free survival of 43.1\ua0months. After a mean follow-up of 47 (range 4\u2013180) months, 89.5% of patients were alive and disease-free. Although rare, when dealing with a solid-cystic pancreatic mass, even in asymptomatic male patients, a pSPN should be considered as a possible diagnosis