Current research in necrotizing enterocolitis

Despite decades of research on necrotizing enterocolitis, we still do not fully understand the pathogenesis of the disease, how to prevent or how to treat the disease. However, as a result of recent significant advances in the microbiology, molecular biology, and cell biology of the intestine of premature infants and infants with necrotizing enterocolitis, there is some hope that research into this devastating disease will yield some important translation into improved outcomes

Barrett's oesophagus and oesophageal cancer following oesophageal atresia repair: a systematic review

BACKGROUND: Concern exists that patients born with oesophageal atresia (OA) may be at high risk for Barrett's oesophagus (BO), a known malignant precursor to the development of oesophageal adenocarcinoma. Screening endoscopy has a role in early BO identification but is not universal in this population. This study aimed to determine prevalence of BO after OA repair surgery, to quantify the magnitude of this association and inform the need for screening and surveillance. METHODS: A systematic review, undertaken according to PRISMA guidelines, was preregistered on PROSPERO (CRD42017081001). PubMed and EMBASE were interrogated using a standardized search strategy on 31 July 2020. Included papers, published in English, reported either: one or more patients with either BO (gastric/intestinal metaplasia) or oesophageal cancer in patients born with OA; or long-term (greater than 2 years) follow-up after OA surgery with or without endoscopic screening or surveillance. RESULTS: Some 134 studies were identified, including 19 case reports or series and 115 single- or multi-centre cohort studies. There were 13 cases of oesophageal cancer (9 squamous cell carcinoma, 4 adenocarcinoma) with a mean age at diagnosis of 40.5 (range 20-47) years. From 6282 patients under long-term follow-up, 317 patients with BO were reported. Overall prevalence of BO was 5.0 (95 per cent c.i. 4.5 to 5.6) per cent, with a mean age at detection of 13.8 years (range 8 months to 56 years). Prevalence of BO in series reporting endoscopic screening or surveillance was 12.8 (95 per cent c.i. 11.3 to 14.5) per cent. CONCLUSION: Despite a limited number of cancers, the prevalence of BO in patients born with OA is relatively high. While limited by the quality of available evidence, this review suggests endoscopic screening and surveillance may be warranted, but uncertainties remain over the design and effectiveness of any putative programme

Non-operative management of appendicitis in children

While appendicectomy has been considered the mainstay of treatment for children with acute appendicitis for many decades, there has been a great deal of recent interest in non-operative treatment (NOT) with antibiotics alone. Initial results suggest that many children with appendicitis can indeed be safely treated with NOT and can be spared the surgeon’s knife. Many as yet unanswered questions remain, however, before NOT can be considered a realistic and reliable alternative to surgery. This review summaries current knowledge and understanding of the role of NOT in children with appendicitis and outlines and discusses the outstanding knowledge gaps

Flavor Structure in F-theory Compactifications

F-theory is one of frameworks in string theory where supersymmetric grand unification is accommodated, and all the Yukawa couplings and Majorana masses of right-handed neutrinos are generated. Yukawa couplings of charged fermions are generated at codimension-3 singularities, and a contribution from a given singularity point is known to be approximately rank 1. Thus, the approximate rank of Yukawa matrices in low-energy effective theory of generic F-theory compactifications are minimum of either the number of generations N_gen = 3 or the number of singularity points of certain types. If there is a geometry with only one E_6 type point and one D_6 type point over the entire 7-brane for SU(5) gauge fields, F-theory compactified on such a geometry would reproduce approximately rank-1 Yukawa matrices in the real world. We found, however, that there is no such geometry. Thus, it is a problem how to generate hierarchical Yukawa eigenvalues in F-theory compactifications. A solution in the literature so far is to take an appropriate factorization limit. In this article, we propose an alternative solution to the hierarchical structure problem (which requires to tune some parameters) by studying how zero mode wavefunctions depend on complex structure moduli. In this solution, the N_gen x N_gen CKM matrix is predicted to have only N_gen entries of order unity without an extra tuning of parameters, and the lepton flavor anarchy is predicted for the lepton mixing matrix. We also obtained a precise description of zero mode wavefunctions near the E_6 type singularity points, where the up-type Yukawa couplings are generated.Comment: 148 page

Genomic variations define divergence of water/wildlife-associated Campylobacter jejuni niche specialists from common clonal complexes

Although the major food-borne pathogen Campylobacter jejuni has been isolated from diverse animal, human and environmental sources, our knowledge of genomic diversity in C. jejuni is based exclusively on human or human food-chain-associated isolates. Studies employing multilocus sequence typing have indicated that some clonal complexes are more commonly associated with particular sources. Using comparative genomic hybridization on a collection of 80 isolates representing diverse sources and clonal complexes, we identified a separate clade comprising a group of water/wildlife isolates of C. jejuni with multilocus sequence types uncharacteristic of human food-chain-associated isolates. By genome sequencing one representative of this diverse group (C. jejuni 1336), and a representative of the bank-vole niche specialist ST-3704 (C. jejuni 414), we identified deletions of genomic regions normally carried by human food-chain-associated C. jejuni. Several of the deleted regions included genes implicated in chicken colonization or in virulence. Novel genomic insertions contributing to the accessory genomes of strains 1336 and 414 were identified. Comparative analysis using PCR assays indicated that novel regions were common but not ubiquitous among the water/wildlife group of isolates, indicating further genomic diversity among this group, whereas all ST-3704 isolates carried the same novel accessory regions. While strain 1336 was able to colonize chicks, strain 414 was not, suggesting that regions specifically absent from the genome of strain 414 may play an important role in this common route of Campylobacter infection of humans. We suggest that the genomic divergence observed constitutes evidence of adaptation leading to niche specialization

Assessment of space proton radiation-induced charge transfer inefficiency in the CCD204 for the Euclid space observatory

Euclid is a medium class European Space Agency mission candidate for launch in 2019 with a primary goal to study the dark universe using the weak lensing and baryonic acoustic oscillations techniques. Weak lensing depends on accurate shape measurements of distant galaxies. Therefore it is beneficial that the effects of radiation-induced charge transfer inefficiency (CTI) in the Euclid CCDs over the course of the 5 year mission at L2 are understood. This will allow, through experimental analysis and modelling techniques, the effects of radiation induced CTI on shape to be decoupled from those of mass inhomogeneities along the line-of-sight. This paper discusses a selection of work from the study that has been undertaken using the e2v CCD204 as part of the initial proton radiation damage assessment for Euclid. The experimental arrangement and procedure are described followed by the results obtained, thereby allowing recommendations to be made on the CCD operating temperature, to provide an insight into CTI effects using an optical background, to assess the benefits of using charge injection on CTI recovery and the effect of the use of two different methods of serial clocking on serial CTI. This work will form the basis of a comparison with a p-channel CCD204 fabricated using the same mask set as the n-channel equivalent. A custom CCD has been designed, based on this work and discussions between e2v technologies plc. and the Euclid consortium, and designated the CCD273

Decomposition process in a FeAuPd alloy nanostructured by severe plastic deformation

The decomposition process mechanisms have been investigated in a Fe50Au25Pd25 (at.%) alloy processed by severe plastic deformation. Phases were characterized by X-ray diffraction and microstructures were observed using transmission electron microscopy. In the coarse grain alloy homogenized and aged at $450 ^{circ}\mathrm{C}$, the bcc \alpha-Fe and fcc AuPd phases nucleate in the fcc supersaturated solid solution and grow by a discontinuous precipitation process resulting in a typical lamellar structure. The grain size of the homogenized FeAuPd alloy was reduced in a range of 50 to 100nm by high pressure torsion. Aging at $450 ^{circ}\mathrm{C}$ this nanostructure leads to the decomposition of the solid solution into an equi-axed microstructure. The grain growth is very limited during aging and the grain size remains under 100nm. The combination of two phases with different crystallographic structures (bcc \alpha-Fe and fcc AuPd) and of the nanoscaled grain size gives rise to a significant hardening of the allo