Quantitative analysis on electric dipole energy in Rashba band splitting

We report on quantitative comparison between the electric dipole energy and the Rashba band splitting in model systems of Bi and Sb triangular monolayers under a perpendicular electric field. We used both first-principles and tight binding calculations on p-orbitals with spin-orbit coupling. First-principles calculation shows Rashba band splitting in both systems. It also shows asymmetric charge distributions in the Rashba split bands which are induced by the orbital angular momentum. We calculated the electric dipole energies from coupling of the asymmetric charge distribution and external electric field, and compared it to the Rashba splitting. Remarkably, the total split energy is found to come mostly from the difference in the electric dipole energy for both Bi and Sb systems. A perturbative approach for long wave length limit starting from tight binding calculation also supports that the Rashba band splitting originates mostly from the electric dipole energy difference in the strong atomic spin-orbit coupling regime.1131Ysciescopu

Difference of clinical features in childhood Mycoplasma pneumoniae pneumonia

<p>Abstract</p> <p>Background</p> <p><it>M. pneumoniae </it>pneumonia (MP) has been reported in 10-40% of community-acquired pneumonia cases. We aimed to evaluate the difference of clinical features in children with MP, according to their age and chest radiographic patterns.</p> <p>Methods</p> <p>The diagnosis of MP was made by examinations at both admission and discharge and by two serologic tests: the indirect microparticle agglutinin assay (≥1:40) and the cold agglutinins titer (≥1:32). A total of 191 children with MP were grouped by age: ≤2 years of age (29 patients), 3-5 years of age (81 patients), and ≥6 years of age (81 patients). They were also grouped by pneumonia pattern: bronchopneumonia group (96 patients) and segmental/lobar pneumonia group (95 patients).</p> <p>Results</p> <p>Eighty-six patients (45%) were seroconverters, and the others showed increased antibody titers during hospitalization. Among the three age groups, the oldest children showed the longest duration of fever, highest C-reactive protein (CRP) values, and the most severe pneumonia pattern. The patients with segmental/lobar pneumonia were older and had longer fever duration and lower white blood cell (WBC) and lymphocyte counts, compared with those with bronchopneumonia. The patient group with the most severe pulmonary lesions had the most prolonged fever, highest CRP, highest rate of seroconverters, and lowest lymphocyte counts. Thrombocytosis was observed in 8% of patients at admission, but in 33% of patients at discharge.</p> <p>Conclusions</p> <p>In MP, older children had more prolonged fever and more severe pulmonary lesions. The severity of pulmonary lesions was associated with the absence of diagnostic IgM antibodies at presentation and lymphocyte count. Short-term paired IgM serologic test may be mandatory for early and definitive diagnosis of MP.</p

Enhancement of PLA-PVA surface adhesion in bilayer assemblies by PLA aminolisation

Data Availability: The raw/processed data required to reproduce these findings cannot be shared at this time due to legal or ethical reasons.Poly(lactic acid) (PLA) and poly(vinyl alcohol) (PVA) present complementary barrier properties, and their combination in multilayer assemblies (laminates) could provide materials with more effective barrier capacity for food packaging purposes. However, their low chemical affinity compromises adequate polymer adhesion. Surface free energy modification of thermo-processed PLA films through treatment with 1,6-hexanediamine was used to enhance adhesion with polar PVA aqueous solutions. Treatments of 1 and 3 min increased the polar component of the solid surface tension, while treatments above 10 min provoked a corrosive effect in the films structure. Extensibility analyses of PVA solutions loaded with carvacrol (15 wt.%) and different Tween 85 ratios on PLA-activated surfaces allowed the selection of the 1-min aminolysed surface for obtaining PLA-PVA bilayers, by casting PVA solutions on the PLA films. This study revealed that despite aminolisation enhancing the PLA surface affinity for aqueous PVA solutions, casting-obtained bilayers presented limited oxygen barrier effectiveness due to heterogeneous thickness of PVA layer in the laminates.The authors acknowledge the financial support provided by the Ministerio de Economia y Competitividad (MINECO) of Spain (project AGL2016-76699-R). The author A. Tampau thanks MINECO for the pre-doctoral research grant #BES-2014-068100.info:eu-repo/semantics/publishedVersio

Physical characterisation of an alginate/lysozyme nano-laminate coating and its evaluation on ‘coalho’ cheese shelf life

This work aimed at the characterisation of a nanolaminate coating produced by the layer-by-layer methodology and its evaluation on the preservation of ‘Coalho’ cheese. Initially, five alternate layers of alginate and lysozyme were assembled in an aminolysed/charged polyethylene terephthalate (A/C PET) and physically characterised by UV/VIS spectroscopy, contact angle, water vapour (WVTR) and oxygen (OTR) transmission rates and scanning electron microscopy. Afterwards, the same methodology was used to apply the nano-laminate coating in ‘Coalho’ cheese and its shelf life was evaluated during 20 days in terms of mass loss, pH, lipid peroxidation, titratable acidity and microbial count. UV/VIS spectroscopy and contact angle analyses confirmed the layers’ deposition and the successful assembly of nano-laminate coating on A/C PET surface. The coating presented WVTR and OTR values of 1.03×10−3 and 1.28× 10−4 g m−2 s−1, respectively. After 20 days, coated cheese showed lower values of mass loss, pH, lipidic peroxidation, microorganisms’ proliferation and higher titratable acidity in comparison with uncoated cheese. These results suggest that gas barrier and antibacterial properties of alginate/lysozyme nanocoating can be used to extend the shelf life of ‘Coalho’ cheese.The author Bartolomeu G. de S. Medeiros is recipient of a scholarship from Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES-Brazil). The author Marthyna P. Souza is recipient of a scholarship from Fundacao de Amparo a Ciencia e Tecnologia do Estado de Pernambuco (FACEPE, Brazil) and was recipient of a scholarship from Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES/PDEE-Brazil). The authors Ana C. Pinheiro, Ana I. Bourbon and Miguel A. Cerqueira are recipients of a fellowship (SFRH/BD/48120/2008, SFRH/BD/73178/2010 and SFRH/BPD/72753/2010, respectively), supported by Fundacao para a Ciencia e Tecnologia, POPH-QREN and FSE (FCT, Portugal). Maria G. Carneiro-da-Cunha express is gratitude to the Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) for research grant. The present work was supported by CAPES/PROCAD/NF/1415/2007. The support of EU Cost Action FA0904 is gratefully acknowledged

Assessing the Advantages, Limitations and Potential of Human Primary Prostate Epithelial Cells as a Pre-clinical Model for Prostate Cancer Research

Choosing an appropriate cell model(s) is the first decision to be made before starting a new project or programme of study. Here, we address the rationale that can be behind this decision and we summarize the current cell models that are used to study prostate cancer. Researchers face the challenge of choosing a model that recapitulates the complexity and heterogeneity of prostate cancer. The use of primary prostate epithelial cells cultured from patient tissue is discussed, and the necessity for close clinical-academic collaboration in order to do this is highlighted. Finally, a novel quantitative phase imaging technique is described, along with the potential for cell characterization to not only include gene expression and protein markers but also morphological features, cell behaviour and kinetic activity

Approaches in biotechnological applications of natural polymers

Natural polymers, such as gums and mucilage, are biocompatible, cheap, easily available and non-toxic materials of native origin. These polymers are increasingly preferred over synthetic materials for industrial applications due to their intrinsic properties, as well as they are considered alternative sources of raw materials since they present characteristics of sustainability, biodegradability and biosafety. As definition, gums and mucilages are polysaccharides or complex carbohydrates consisting of one or more monosaccharides or their derivatives linked in bewildering variety of linkages and structures. Natural gums are considered polysaccharides naturally occurring in varieties of plant seeds and exudates, tree or shrub exudates, seaweed extracts, fungi, bacteria, and animal sources. Water-soluble gums, also known as hydrocolloids, are considered exudates and are pathological products; therefore, they do not form a part of cell wall. On the other hand, mucilages are part of cell and physiological products. It is important to highlight that gums represent the largest amounts of polymer materials derived from plants. Gums have enormously large and broad applications in both food and non-food industries, being commonly used as thickening, binding, emulsifying, suspending, stabilizing agents and matrices for drug release in pharmaceutical and cosmetic industries. In the food industry, their gelling properties and the ability to mold edible films and coatings are extensively studied. The use of gums depends on the intrinsic properties that they provide, often at costs below those of synthetic polymers. For upgrading the value of gums, they are being processed into various forms, including the most recent nanomaterials, for various biotechnological applications. Thus, the main natural polymers including galactomannans, cellulose, chitin, agar, carrageenan, alginate, cashew gum, pectin and starch, in addition to the current researches about them are reviewed in this article.. }To the Conselho Nacional de Desenvolvimento Cientfíico e Tecnológico (CNPq) for fellowships (LCBBC and MGCC) and the Coordenação de Aperfeiçoamento de Pessoal de Nvíel Superior (CAPES) (PBSA). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and COMPETE 2020 (POCI-01-0145-FEDER-006684) (JAT)

Antimicrobial activity of Ti-ZrN/Ag coatings for use in biomaterial applications

Severely broken bones often require external bone fixation pins to provide support but they can become infected. In order to reduce such infections, novel solutions are required. Titanium zirconium nitride (Ti-ZrN) and Ti-ZrN silver (Ti-ZrN/Ag) coatings were deposited onto stainless steel. Surface microtopography demonstrated that on the silver containing surfaces, Sa and Sv values demonstrated similar trends whilst the Ra, average height and RMS value and Sp values increased with increasing silver concentration. On the Ti-ZrN/Ag coatings, surface hydrophobicity followed the same trend as the Sa and Sv values. An increase in dead Staphylococcus aureus and Staphylococcus epidermidis cells was observed on the coatings with a higher silver concentration. Using CTC staining, a significant increase in S. aureus respiration on the silver containing surfaces was observed in comparison to the stainless steel control whilst against S. epidermidis, no significant difference in viable cells was observed across the surfaces. Cytotoxicity testing revealed that the TiZrN coatings, both with and without varying silver concentrations, did not possess a detrimental effect to a human monocyte cell line U937. This work demonstrated that such coatings have the potential to reduce the viability of bacteria that result in pin tract infections