Dielectric behavior of some polar high polymers at ultra-high frequencies (microwaves)

The dielectric behavior of different polar high polymers at ultra-high frequencies has been investigated by means of a dielectrometer, suitably modified to permit measurements at different temperatures. Experimental measurements were made at about 9 × 10⁹ cps over the temperature range of ?150 to 200°C. for polyoxymethylene, polythiomethylene, poly(3,3′-chloromethyl)oxetane (Penton), polycarbonate of 4,4′-dioxydiphenyl-2,2′-propane (Makrolon), poly(vinyl alcohol), poly(vinyl acetate), poly(vinyl chloride), vinyl chloride–vinyl acetate copolymer, and two ABS plastics, type B (blend) and type G (graft). On comparing the dielectric behavior of the examined materials at ultra-high frequencies with the corresponding ones determined at low or at radiofrequencies, it is observed that, in the microwave region, all relaxation peaks, either connected with cooperative motions in main chain (primary processes) or with local motions in the backbone or in side chains (secondary processes), usually observed at lower frequencies, tend to disappear; the corresponding relaxation effects, however, manifest themselves through a progressive increase of losses with increasing temperature, which is particularly marked above the glass transition temperature T_g. The latter transition, in spite of the very high frequency, is easily distinguished, in most cases, by the sudden change of slope in the tan δ versus temperature curve which accompanies its onset. This is explained on the basis of the very wide distribution times of molecular relaxation processes in polymers and the increase in strength of the secondary relaxation effects, which is verified at T_g, as a consequence of the increased kinetic energy of macromolecules and of the larger free volume for orientation of side chains. Each case is discussed separately and the experimental results interpreted on the basis of the molecular structure and chain mobility of the examined polymers.     

Dietary Habits and Gut Microbiota in Healthy Adults: Focusing on the Right Diet. A Systematic Review

Diet is the first to affect our intestinal microbiota and therefore the state of eubiosis. Several studies are highlighting the potential benefits of taking certain nutritional supplements, but a dietary regime that can ensure the health of the intestinal microbiota, and the many pathways it governs, is not yet clearly defined. We performed a systematic review of the main studies concerning the impact of an omnivorous diet on the composition of the microbiota and the production of short-chain fatty acids (SCFAs). Some genera and phyla of interest emerged significantly and about half of the studies evaluated consider them to have an equally significant impact on the production of SCFAs, to be a source of nutrition for our colon cells, and many other processes. Although numerous randomized trials are still needed, the Mediterranean diet could play a valuable role in ensuring our health through direct interaction with our microbiota.     

A generalized reduced fluid dynamic model for flow fields and electrodes in redox flow batteries

High-dimensional models typically require a large computational overhead for multiphysics applications, which hamper their use for broad-sweeping domain interrogation. Herein, we develop a modeling framework to capture the through-plane fluid dynamic response of electrodes and flow fields in a redox flow cell, generating a computationally inexpensive two-dimensional (2D) model. We leverage a depth-averaging approach that also accounts for variations in out-of-plane fluid motion and departures from Darcy's law that arise from averaging across three-dimensions (3D). Our resulting depth-averaged 2D model successfully predicts the fluid dynamic response of arbitrary in-plane flow field geometries, with discrepancies of <5% for both maximum velocity and pressure drop. This corresponds to reduced computational expense, as compared to 3D representations (<1% of duration and 10% of RAM usage), providing a platform to screen and optimize a diverse set of cell geometries.     

Separation of some light monocarboxylic acids from water inbinary solutions in a reverse osmosis pilot plant

The separation of formic (C₁), acetic (C₂), propionic (C₃), and n-valeric (C₅) acids in binary water solutions has been studied using a reverse osmosis (RO) membrane pilot plant operating at different temperatures and pressures (usually 21 °C and 1.72 MPa). The RO membrane, which is composite, polyamide and spiral-wound, having a surface area of 2.6 m², was fed by a solution of 0.5 M of C₁, C₂ and C₃ acids and 0.146 M of C₅. The pilot plant was used to simulate a cascade series of RO modules by recycling the permeate flux at the end of each semi-batch run. The influence on the retention coefficient, R, of molecular weight and molar volume, pK_a of the different acids was determined. For acetic acid the influence of temperature (T) and transmembrane pressure (ΔP) was also studied, obtaining an inverse and direct good linear correlation for R vs. T and R vs. ΔP, respectively. The results are particularly interesting for acetic acid-water separation, which is an open question in industrial applications.     

Tungsten Trioxide Films with Controlled Morphology and Strong Photocatalytic Activity via a Simple Sol–Gel Route

Novel nanostructured tungsten trioxide (WO₃) films with strong photocatalytic activity, have been prepared by a simple sol–gel route from aqueous peroxopolytungstic acid (PTA) precursor solutions. We demonstrate that films with different morphologies can be synthesized by simply adjusting the pH of this precursor solution using different mineral acids such as HCl and HC1O₄, and that this control of film texture represents a way of optimizing photocurrent yield. The best films produced using these methods generated anodic photocurrents of 3.8 mA/cm² for oxidiation of methanol and 2.2 mA/cm ² for water splitting, under AM1.5 simulated solar illumination.     

Age differences in personality across the adult life span: Parallels in five cultures.

Both cross-sectional and longitudinal studies in the United States have shown consistent changes between college age and middle adulthood. There appear to be declines in 3 of the 5 major factors of personality-Neuroticism, Extraversion, and Openness-and increases in Agreeableness and Conscientiousness. To examine cross-cultural generalizability of these findings, translations of the Revised NEO Personality Inventory were administered to samples in Germany, Italy, Portugal, Croatia, and South Korea (N?=?7,363). Similar patterns of age differences were seen in each country, for both men and women. Common trends were also seen for the more specific traits that define the major factors. Because these nations differ substantially in culture and recent history, results suggest the hypothesis that these are universal maturational changes in adult personality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Upgrading biomass wastes in chemical technology. Humic acid‐like matter isolated from compost as chemical auxiliary for textile dyeing

BACKGROUND: In the context of the modern concern regarding rapid consumption and low availability of fossil sources of energy and chemicals, urban and agro‐industrial sources of chemicals represent interesting environmentally friendly alternatives. A recent paper has shown that a humic acid‐like material extracted from urban and green wastes compost exhibits very good surfactant properties. A large number of technological applications could possibly use this material as a chemical auxiliary. This paper reports on the performance of the material as a chemical auxiliary in textile dyeing. RESULTS: The compost‐isolated humic acid‐like bio‐surfactant is shown to perform in nylon 6 microfiber dyeing by water soluble and insoluble dyes as well as and more conveniently than commercial sodium dodecylsulfate (SDS) and sodium dodecylbenzenesulfonate (SDBS). With both types of dye the bio‐surfactant allows the same quality of dyed product as the synthetic surfactants do, but at lower additive concentration. From process cost and environmental impact points of view, the bio‐surfactant has the advantages of operating at much lower additive concentrations and should be available at significantly lower cost than the synthetic surfactants. CONCLUSION: The results suggest that biomass wastes may be a low cost renewable source of chemicals with friendly environmental impact. Such a perspective implies economic and environmental benefits deriving from a new waste management technology that considers biomass waste as a source of chemicals, and from lower oil consumption in the manufacture of synthetic surfactants. Copyright © 2007 Society of Chemical Industry     

Diffuse Axonal Injury: Clinical Prognostic Factors,Molecular Experimental Models and the Impact of the Trauma Related Oxidative Stress. An Extensive Review Concerning Milestones and Advances

Traumatic brain injury (TBI) is a condition burdened by an extremely high rate of morbidity and mortality and can result in an overall disability rate as high as 50% in affected individuals. Therefore, the importance of identifying clinical prognostic factors for diffuse axonal injury (DAI) in (TBI) is commonly recognized as critical. The aim of the present review paper is to evaluate the most recent contributions from the relevant literature in order to understand how each single prognostic factor determinates the severity of the clinical syndrome associated with DAI. The main clinical factors with an important impact on prognosis in case of DAI are glycemia, early GCS, the peripheral oxygen saturation, blood pressure, and time to recover consciousness. In addition, the severity of the lesion, classified on the ground of the cerebral anatomical structures involved after the trauma, has a strong correlation with survival after DAI. In conclusion, modern findings concerning the role of reactive oxygen species (ROS) and oxidative stress in DAI suggest that biomarkers such as GFAP, pNF-H, NF-L, microtubule associated protein tau, Aβ42, S-100β, NSE, AQP4, Drp-1, and NCX represent a possible critical target for future pharmaceutical treatments to prevent the damages caused by DAI.     

Bioprospecting Antimicrobials from Lactiplantibacillus plantarum: Key Factors Underlying Its Probiotic Action

Lactiplantibacillus plantarum (L. plantarum) is a well-studied and versatile species of lactobacilli. It is found in several niches, including human mucosal surfaces, and it is largely employed in the food industry and boasts a millenary tradition of safe use, sharing a long-lasting relationship with humans. L. plantarum is generally recognised as safe and exhibits a strong probiotic character, so that several strains are commercialised as health-promoting supplements and functional food products. For these reasons, L. plantarum represents a valuable model to gain insight into the nature and mechanisms of antimicrobials as key factors underlying the probiotic action of health-promoting microbes. Probiotic antimicrobials can inhibit the growth of pathogens in the gut ensuring the intestinal homeostasis and contributing to the host health. Furthermore, they may be attractive alternatives to conventional antibiotics, holding potential in several biomedical applications. The aim of this review is to investigate the most relevant papers published in the last ten years, bioprospecting the antimicrobial activity of characterised probiotic L. plantarum strains. Specifically, it focuses on the different chemical nature, the action spectra and the mechanisms underlying the bioactivity of their antibacterial and antiviral agents. Emerging trends in postbiotics, some in vivo applications of L. plantarum antimicrobials, including strengths and limitations of their therapeutic potential, are addressed and discussed.     

Mast Cell Cytokines in Acute and Chronic Gingival Tissue Inflammation: Role of IL-33 and IL-37

Much evidence suggests autoimmunity in the etiopathogenesis of periodontal disease. In fact, in periodontitis, there is antibody production against collagen, DNA, and IgG, as well as increased IgA expression, T cell dysfunction, high expression of class II MHC molecules on the surface of gingival epithelial cells in inflamed tissues, activation of NK cells, and the generation of antibodies against the azurophil granules of polymorphonuclear leukocytes. In general, direct activation of autoreactive immune cells and production of TNF can activate neutrophils to release pro-inflammatory enzymes with tissue damage in the gingiva. Gingival inflammation and, in the most serious cases, periodontitis, are mainly due to the dysbiosis of the commensal oral microbiota that triggers the immune system. This inflammatory pathological state can affect the periodontal ligament, bone, and the entire gingival tissue. Oral tolerance can be abrogated by some cytokines produced by epithelial cells and activated immune cells, including mast cells (MCs). Periodontal cells and inflammatory–immune cells, including mast cells (MCs), produce cytokines and chemokines, mediating local inflammation of the gingival, along with destruction of the periodontal ligament and alveolar bone. Immune-cell activation and recruitment can be induced by inflammatory cytokines, such as IL-1, TNF, IL-33, and bacterial products, including lipopolysaccharide (LPS). IL-1 and IL-33 are pleiotropic cytokines from members of the IL-1 family, which mediate inflammation of MCs and contribute to many key features of periodontitis and other inflammatory disorders. IL-33 activates several immune cells, including lymphocytes, Th2 cells, and MCs in both innate and acquired immunological diseases. The classic therapies for periodontitis include non-surgical periodontal treatment, surgery, antibiotics, anti-inflammatory drugs, and surgery, which have been only partially effective. Recently, a natural cytokine, IL-37, a member of the IL-1 family and a suppressor of IL-1b, has received considerable attention for the treatment of inflammatory diseases. In this article, we report that IL-37 may be an important and effective therapeutic cytokine that may inhibit periodontal inflammation. The purpose of this paper is to study the relationship between MCs, IL-1, IL-33, and IL-37 inhibition in acute and chronic inflamed gingival tissue.