Distinctive Microbial Signatures and Gut-Brain Crosstalk in Pediatric Patients with Coeliac Disease and Type 1 Diabetes Mellitus

Coeliac disease (CD) and Type 1 diabetes mellitus (T1DM) are immune-mediated diseases. Emerging evidence suggests that dysbiosis in the gut microbiome plays a role in the pathogenesis of both diseases and may also be associated with the development of neuropathy. The primary goal in this cross-sectional pilot study was to identify whether there are distinct gut microbiota alterations in children with CD (n = 19), T1DM (n = 18) and both CD and T1DM (n = 9) compared to healthy controls (n = 12). Our second goal was to explore the relationship between neuropathy (corneal nerve fiber damage) and the gut microbiome composition. Microbiota composition was determined by 16S rRNA gene sequencing. Corneal confocal microscopy was used to determine nerve fiber damage. There was a significant difference in the overall microbial diversity between the four groups with healthy controls having a greater microbial diversity as compared to the patients. The abundance of pathogenic proteobacteria Shigella and E. coli were significantly higher in CD patients. Differential abundance analysis showed that several bacterial amplicon sequence variants (ASVs) distinguished CD from T1DM. The tissue transglutaminase antibody correlated significantly with a decrease in gut microbial diversity. Furthermore, the Bacteroidetes phylum, specifically the genus Parabacteroides was significantly correlated with corneal nerve fiber loss in the subjects with neuropathic damage belonging to the diseased groups. We conclude that disease-specific gut microbial features traceable down to the ASV level distinguish children with CD from T1DM and specific gut microbial signatures may be associated with small fiber neuropathy. Further research on the mechanisms linking altered microbial diversity with neuropathy are warranted.     

Current trends in structural development and modification strategies for metal-organic frameworks (MOFs) towards photocatalytic H2 production: A review

Photocatalytic H₂ generation using semiconductor photocatalysts is considered as a cost-effective and eco-friendly technology for solar to energy conversion; however, the present photocatalysts have been recognized to depict low efficiency. Currently, porous coordination polymers known as metal-organic frameworks (MOFs) constituting flexible and modifiable porous structure and having excess active sites are considered to be appropriate for photocatalytic H₂ production. This review highlights current progress in structural development of MOF materials along with modification strategies for enhanced photoactivity. Initially, the review discusses the photocatalytic H₂ production mechanism with the concepts of thermodynamics and mass transfer with particular focus on MOFs. Elaboration of the structural categories of MOFs into Type I, Type II, Type III and classification of MOFs for H₂ generation into transition metal based, post-transition metal based, noble-metal based and hetero-metal based has been systematically discussed. The review also critically deliberate various modification approaches of band engineering, improvement of charge separation, efficient irradiation utilization and overall efficiency of MOFs including metal modification, heterojunction formation, Z-scheme formation, by introducing electron mediator, and dye based composites. Also, the MOF synthesized derivatives for photocatalytic H₂ generation are elaborated. Finally, future perspectives of MOFs for H₂ generation and approaches for efficiency improvement have been suggested.     

Flow and crystallization of saturated fatty acid methyl esters and their binary mixtures

Demand for biodiesel has increased due to being a more environmentally-friendly fuel. Cold weather operation of biodiesel is challenging due to fatty acid methyl ester (FAME) content in biodiesel. Saturated FAMEs crystallize at relatively high temperatures, increase the viscosity of biodiesel, and can clog fuel lines. Here, several factors altered crystallization temperature (CT) of FAMEs, including composition, shear rate, and cooling rate. The crystallization of pure and binary mixtures of methyl palmitate, methyl myristate, and methyl stearate were studied under shear flow and static conditions. Static phase CTs of pure methyl palmitate, methyl myristate, and methyl stearate were 26, 14, and 35°C, respectively. In binary mixtures, CTs were depressed up to 7°C, which agreed with freezing point depression theory. Increasing shear rate up to 100 s⁻¹ decreased CT by 2°C compared to static conditions. Decreasing cooling rate from 1 to 0.1°C/min increased CT less than 2°C. Overall, FAME composition altered CT more than shear flow or cooling rate for pure and binary mixtures of three FAMEs.     

Finite Element Analysis of a Copper Single Crystal Shape Memory Alloy-Based Endodontic Instruments

The aim of the present paper is the development of endodontic Cu-based single crystal Shape Memory Alloy (SMA) instruments in order to eliminate the antimicrobial and mechanical deficiencies observed with the conventional Nickel-Titane (NiTi) SMA files. A thermomechanical constitutive law, already developed and implemented in a finite element code by our research group, is adopted for the simulation of the single crystal SMA behavior. The corresponding material parameters were identified starting from experimental results for a tensile test at room temperature. A computer-aided design geometry has been achieved and considered for a finite element structural analysis of the endodontic Cu-based single crystal SMA files. They are meshed with tetrahedral continuum elements to improve the computation time and the accuracy of results. The geometric parameters tested in this study are the length of the active blade, the rod length, the pitch, the taper, the tip diameter, and the rod diameter. For each set of adopted parameters, a finite element model is built and tested in a combined bending-torsion loading in accordance with ISO 3630-1 norm. The numerical analysis based on finite element procedure allowed purposing an optimal geometry suitable for Cu-based single crystal SMA endodontic files. The same analysis was carried out for the classical NiTi SMA files and a comparison was made between the two kinds of files. It showed that Cu-based single crystal SMA files are less stiff than the NiTi files. The Cu-based endodontic files could be used to improve the root canal treatments. However, the finite element analysis brought out the need for further investigation based on experiments.     

Direct Growth and Photoluminescence of SiO<Subscript>x</Subscript> Nanowires and Aligned Nanocakes by Simple Carbothermal Evaporation

The growth of SiO_x nanowires and nanocakes on an Au-coated n-type-Silicon (100) substrate was achieved via carbothermal evaporation. The effects of the Au layer thickness and the rapid heating rate on the morphology of obtained SiO_x nanowires were investigated. A broad emission band from 290 to 600 nm was observed in the photoluminescence (PL) spectrum of these nanowires. There are four PL peaks: one blue emission peak 485 nm (2.56 eV) two green bands centered at 502 nm (2.47 eV) and 524 nm (2.37 eV) for nanocakes and one ultraviolet emission peak at 350 nm (3.54 eV) and a hemisphere curve over the bluish green area taken for SiO_x nanowires. These emissions may be related to the various oxygen defects and twofold coordinated silicon lone pair centers.     

PERIODIC VARIATIONS OF LANTHANIDES YKERGIC EXTRACTION BY THENOYLTRI-FLUOROACETONE AND TRIPHENYLPHOSPHINE OXIDE MIXTURE∗

Abstract

The synergic extraction of the different lanthani-des, except Pm and Lu, by thenoyltrifluoroacetone (HTTA) and triphenylphosphine oxide (TPPO) mixture in benzene from an aqueous perchlorate medium of constant ionic strength of 0·2 was investigated. It was found that the main adduct extracted contains the lanthanide chelates together with two TPPO molecules. The different extraction and formation constants for the lanthanides investigated have been determined. The variations of the logarithmic values of the chelate extraction constant and the adduct formation constant with the different lanthanides was discussed in the light of the tetrad and the inclined-W effects. The experimental results showed that the nature of coordination by adduct formation for the Yb-Sm group is different than that of the Pr-La group.     

Drivers for software development method usage

In this research, the authors examine factors affecting the use of product development methods. Based on established behavioral theories, they develop and test a model that can explain, and hence predict, the extent of use of development methods. Although their model can be adapted to any development process, they apply it to software development. To test their model, they examine the combined effects of a number of important usage factors that contribute to the depth and breadth of use of two software development approaches: the waterfall model and prototyping. Two main constructs, process quality and facilitating conditions, are found to be the drivers of method usage. The dominating “facilitating conditions” and “process quality” indicators vary from one method to another product quality was not found to be a statistically significant factor in explaining usage. The authors' results are consistent with the view taken by the software process improvement movement, i.e., that a quality process will result in a quality product