Bulk nanocrystalline aluminum 5083 alloy fabricated by a novel technique: Cryomilling and spark plasma sintering

Dense, bulk nanocrystalline aluminum 5083 alloy was fabricatedvia a combined technique: cryomilling (mechanical milling at cryogenic temperature) to achieve the nanocrystalline Al 5083 powder and spark plasma sintering (SPS) to consolidate the cryomilled powder. The results of X-ray diffraction analysis indicate that the average grain size in the SPS consolidated material is 51 nm, one of the smallest grain sizes ever reported in bulk Al alloys produced by powder metallurgy derived methods. In contrast, transmission electron microscopy (TEM) analysis revealed a bimodal grain size distribution, with an average grain size of 47 nm in the fine-grained regions and approximately 300 nm in the coarse-grained regions. Nanoindentation was used to evaluate the mechanical properties and the uniformity of the consolidated nanocrystalline Al 5083. The hardness of the material is greatly improved over that of the conventional equivalent, due to the fine grain size. The mechanisms for spark plasma sintering and the microstructural evolution are discussed on the basis of the experimental findings.     

Adaptation and validation of the Spanish-language Trauma Symptom Inventory in Puerto Rico.

Objective: This research was conducted to assess the Spanish-language Trauma Symptom Inventory's (Briere, 1995) suitability for use with a Puerto Rican sample. Minor revisions were made to the original instrument following a comprehensive appraisal involving a bilingual committee and pilot focus group. The present study outlines the review and adaptation process and examines the psychometric properties of the revised instrument, the Inventario de Síntomas de Trauma-Revisado (IST–R). Method: A sample of 225 students (155 women, 70 men) at the University of Puerto Rico, age 20 to 59 (M = 23.24, SD = 4.69), participated in the validation study. Participants completed a demographic questionnaire; a self-report trauma exposure instrument; and measures of psychological distress, including Spanish-language versions of the Beck Depression Inventory, Symptom Checklist—36, and the Dissociative Experiences Scale. Results: Reliability coefficients for the IST–R clinical scales ranged from .69 to .91 (mean α = .84), and correlation coefficients were strongest for scales measuring the same constructs. Factor loadings obtained were consistent with those reported in the literature. Results support the internal consistency and construct validity of the IST–R. Conclusions: Culturally and linguistically appropriate assessment instruments are needed to address the mental health needs of diverse populations. Results from this study provide evidence for the clinical and research promise of the IST–R as a screening tool for trauma-related symptoms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tumor-Stroma Ratio and Programmed Cell Death Ligand 1 Expression in Preoperative Biopsy and Matched Laryngeal Carcinoma Surgical Specimen

Programmed cell death ligand 1 (PD-L1) seems to rely on close relations between neoplastic and immune cells in the tumor microenvironment. Tumor to stroma ratio (TSR) has been associated with prognosis in different malignancies. The aims of this exploratory investigation were to analyze for the first time the: (i) association between TSR, PD-L1 expression and other clinical–pathological features in laryngeal squamous cell carcinoma (LSCC) biopsies and paired surgical specimens; (ii) prognostic and predictive role of TSR and PD-L1. TSR, PD-L1 expression (in terms of combined positive score [CPS]), and other clinical–pathological features were analyzed in biopsies and surgical specimens of 43 consecutive LSCC cases. A CPS < 1 evaluated on surgical specimens was associated with a low TSR (stroma rich) on both biopsies and surgical specimens (p = 0.0143 and p = 0.0063). Low TSR showed a significant negative prognostic value when evaluated on both biopsies and surgical specimens (HR = 8.808, p = 0.0003 and HR = 11.207, p = 0.0002). CPS ≥ 1 appeared to be a favorable prognostic factor (HR = 0.100, p = 0.0265). The association between bioptic and surgical specimen TSR and PD-L1 expression should be further investigated for a potential impact on targeted treatments, also with regard to immunotherapeutic protocols.     

DeepHP: A New Gastric Mucosa Histopathology Dataset for Helicobacter pylori Infection Diagnosis

Emerging deep learning-based applications in precision medicine include computational histopathological analysis. However, there is a lack of the required training image datasets to generate classification and detection models. This phenomenon occurs mainly due to human factors that make it difficult to obtain well-annotated data. The present study provides a curated public collection of histopathological images (DeepHP) and a convolutional neural network model for diagnosing gastritis. Images from gastric biopsy histopathological exams were used to investigate the performance of the proposed model in detecting gastric mucosa with Helicobacter pylori infection. The DeepHP database comprises 394,926 histopathological images, of which 111 K were labeled as Helicobacter pylori positive and 283 K were Helicobacter pylori negative. We investigated the classification performance of three Convolutional Neural Network architectures. The models were tested and validated with two distinct image sets of 15% (59K patches) chosen randomly. The VGG16 architecture showed the best results with an Area Under the Curve of 0.998%. The results showed that CNN could be used to classify histopathological images from gastric mucosa with marked precision. Our model evidenced high potential and application in the computational pathology field.     

Early-Life Development of the Bifidobacterial Community in the Infant Gut

The establishment of the gut microbiota poses implications for short and long-term health. Bifidobacterium is an important taxon in early life, being one of the most abundant genera in the infant intestinal microbiota and carrying out key functions for maintaining host-homeostasis. Recent metagenomic studies have shown that different factors, such as gestational age, delivery mode, or feeding habits, affect the gut microbiota establishment at high phylogenetic levels. However, their impact on the specific bifidobacterial populations is not yet well understood. Here we studied the impact of these factors on the different Bifidobacterium species and subspecies at both the quantitative and qualitative levels. Fecal samples were taken from 85 neonates at 2, 10, 30, 90 days of life, and the relative proportions of the different bifidobacterial populations were assessed by 16S rRNA–23S rRNA internal transcribed spacer (ITS) region sequencing. Absolute levels of the main species were determined by q-PCR. Our results showed that the bifidobacterial population establishment is affected by gestational age, delivery mode, and infant feeding, as it is evidenced by qualitative and quantitative changes. These data underline the need for understanding the impact of perinatal factors on the gut microbiota also at low taxonomic levels, especially in the case of relevant microbial populations such as Bifidobacterium. The data obtained provide indications for the selection of the species best suited for the development of bifidobacteria-based products for different groups of neonates and will help to develop rational strategies for favoring a healthy early microbiota development when this process is challenged.     

Occurrence of non-lactic acid bacteria populations involved in protein hydrolysis of cold-stored high moisture Mozzarella cheese

The aim of this study was to analyse non-lactic acid bacteria populations (NLABPs) and evaluate their role in proteolysis of cold-stored high moisture (HM) Mozzarella cheese. NLABPs reached values close to 8 log cfu mL⁻¹ after seven days of cold storage. Sequencing of 16 rDNA and rpoB genes and molecular biotyping allowed to identify 66 bacterial strains belonging to 25 species from 15 genera, mainly represented by Pseudomonas, Acinetobacter, and Rahnella. Fifteen strains showed proteolytic activity values higher than 1000.00 μg Gly mL⁻¹ after 24 h of growth in skimmed milk. Moreover, as shown by Urea-PAGE, 11 proteolytic strains caused partial or total disappearance of at least one of the caseins. Their proteolytic behaviour was assessed even when they grew inside the governing liquid together with HM Mozzarella cheese at 4 °C for 12 days. This is the first report that throws light on the complexity of NLABPs in HM Mozzarella cheese, demonstrating that some strains caused the partial hydrolysis of α, β, and γ caseins on its outer surface where a concomitant wrinkling and successive exfoliation became visible without significant changes in texture characteristics.     

Catalytic activity evaluation for hydrogen production via autothermal reforming of methane

A nickel catalyst (5.75 wt.%) supported on gamma-alumina was evaluated through autothermal reforming of methane (ATR). The reforming process was pointed to hydrogen production, following thermodynamic and stoichiometric predictions. The catalyst was characterised by several methods including atomic absorption spectroscopy (AAS), B.E.T.-N₂, X-ray diffraction (XRD), scanning electron microscope (SEM) and thermal analyses (thermogravimetry, TG; derivate thermogravimetry, DTG; and differential thermal analysis, DTA). Experimental evaluations in a fixed-bed reactor (1023–1123 K, 1.00 bar, 150–400 cm³/min feed) presented methane conversions in the range of 40–65%. The effluent mixtures provided hydrogen yields in the range of 78–84%, carbon monoxide 3–14%, and carbon dioxide 5–18%. High molar H₂/CO ratios, ranging from 8 to 90, were obtained. Operating autothermal conditions (excess of steam, 1023–1123 K, 1.00 bar) provided low coke formation and high hydrogen selectivity (81%) for methane reforming.     

Dynamics and scaling of explosion cratering in granular media

Granular cratering is a ubiquitous phenomenon occurring in various natural and industrial contexts. Although impact‐induced granular cratering has been extensively studied, fewer experiments have been conducted on granular cratering via low‐energy explosions. Here, we study the dynamics and scaling of explosion granular cratering by injecting short pulses of pressurized air in quasi‐two‐dimensional granular media. Through an analysis of the dynamics of explosion processes at different explosion pressures, explosion durations, and burial depths, we identify two regimes, the bubbling and the eruption regimes, in explosion granular cratering. Our experiments explore the distinctive dynamics and crater morphologies of these regimes and show the energy scaling of the size of explosion craters. We compare high‐energy and low‐energy explosion cratering as well as explosion and impact cratering in terms of their energy scalings. Our work illustrates complex granular flows in explosion cratering and provides new insights into the general scaling of granular cratering processes. © 2017 American Institute of Chemical Engineers AIChE J, 64: 2972–2981, 2018