Dense bulk silicon oxycarbide glasses obtained by spark plasma sintering

Dense silicon oxycarbide glasses (SiOC) have been produced by spark plasma sintering (SPS) of SiOC powders. Raw powders were obtained by pyrolysis under nitrogen at 1100 °C of tetraethylorthosilcate/polydimethylsiloxane (TEOS/PDMS) hybrids. SPS experiments were carried out at 1300 and 1500 °C at 10 and 80 MPa and then were studied by chemical analysis, ²⁹Si and ¹³C MAS NMR, ATR, Raman, XRD, FE-SEM, density, porosity, microhardness (H_v) and thermal conductivity (K). The SiOC materials are formed by Si_xOC_4?x units within a silica matrix where silicon carbide and graphite nanodomains are also present. After the SPS treatment the silicon carbide crystallite size is close to 2.5 nm. At 1300 °C and 1500 °C the carbon nanodomain size is close to 3 nm and 2 nm, respectively. H_v values vary from 3.4 to 9.15 GPa, for 30% and 1% of porosity, respectively. Finally, K is always close to 1.38 W m^?1 K^?1.     

Preparation and magnetoelectric properties of NiFe2O4–PZT composites obtained in-situ by gel-combustion method

Magnetoelectric composites of xNiFe₂O₄–(1 ? x)Pb(Zr,Ti)O₃ with x = 2, 5, 10, 20, 30% were prepared by citrate–nitrate combustion using PZT-based template powders. In order to ensure a better connectivity of dissimilar phases, we have used chemical methods for preparation in situ composites, followed by adequate sintering procedure. The structural, microstructural and functional properties of di-phase magnetoelectric composites of NiFe₂O₄–PZT are reported. The XRD analysis is demonstrating the synthesis of pure ferrite phase directly on the ferroelectric templates. An excellent mixing was obtained in the composite powders, as proved by a detailed SEM analysis.The magnetic and dielectric behaviors of the ceramic composites vary with the ratio of the two phases. The dielectric behavior is greatly influenced by the magnetic phase. The magnetoelectric (ME) coefficient was measured as a function of applied DC magnetic field. The maximum ME coefficient (dE/dH) varies from 0.0011 mV/(cm Oe) to 0.5 mV/(cm Oe) with increasing of NF addition.     

Effects of ozonized water and heat treatment on the papaya fruit epidermis

This study examined the effects of O₃ and hot water treatments on the epidermis of Golden papaya fruit. Heat treatments were applied in a hot water brushing (HWB) system. Papayas were brushed under a pressurized hot water rinse stage at 45, 55 and 65 °C for 60 s. In the HWB treatment, 4 ppm ozone was applied to the papayas for 1 or 2 min. The results show that ozone applications did not affect the fruit's cuticular surface, while heat treatments allowed natural fissures on the fruit epidermis to recover. Several crystalloid forms were identified on the epidermis of the papayas after the heat treatments. The predominant crystalloid forms on papayas are tubular and there is a positive response to temperature; the higher the temperature, the larger and more frequent the tubular crystalloids.     

Active nano-CuPt3 electrocatalyst supported on graphene for enhancing reactions at the cathode in all-vanadium redox flow batteries

Graphene-supported monometallic (Pt) and bimetallic (CuPt₃) cubic nanocatalysts have been investigated as new positive electrode materials for improving the VO₂⁺/VO²⁺ redox process occurring in the vanadium redox flow batteries (VRB). High-resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM) have been employed to characterize the electrodes. The presence of the CuPt₃ nanocubes on graphene conferred higher electrocatalytic activity due to the much higher electroactive area compared to that obtained with the Pt nanoparticles. The electrochemical surface area of the nano-(CuPt₃)-decorated graphene electrode was 105% higher compared to non-decorated graphene, being then a promising alternative for improving the VRB.     

Microencapsulation of cashew apple (Anacardium occidentale,L.) juice using a new chitosan–commercial bovine whey protein isolate system in spray drying

The aim of this work was to obtain a new stable food product from cashew apple juice encapsulated by spray-drying technique using chitosan–whey protein isolate systems. The materials were evaluated according to their physicochemical stability during storage at different conditions and characterized with respect to their particle size distribution and structure. Encapsulated commercial and natural juices showed homogenous and unimodal particle size distribution with diameters ranging from 0.2 to 5.0 μm and from 0.2 to 40.0 μm, respectively. Both juices demonstrated higher physicochemical stability for vitamin C and color measurements than their respective non-encapsulated juices. X-ray diffractograms evidenced that the powder juices after the 140th day of storage were still in amorphous state. These results indicate that the new product was effective in protecting sensitive compounds present in the food matrix and it was also able to remain stable throughout the study period.     

Characterisation of the Dynamic Interactions between Complex N-Glycans and Human CD22

CD22 (Siglec-2) is a B-cell surface inhibitory protein capable of selectively recognising sialylated glycans, thus dampening autoimmune responses against self-antigens. Here we have characterised the dynamic recognition of complex-type N-glycans by human CD22 by means of orthogonal approaches including NMR spectroscopy, computational methods and biophysical assays. We provide new molecular insights into the binding mode of sialoglycans in complex with h-CD22, highlighting the role of the sialic acid galactose moieties in the recognition process, elucidating the conformational behaviour of complex-type N-glycans bound to Siglec-2 and dissecting the formation of CD22 homo-oligomers on the B-cell surface. Our results could enable the development of additional therapeutics capable of modulating the activity of h-CD22 in autoimmune diseases and malignancies derived from B-cells.     

Association between dietary patterns and metabolic syndrome in a sample of portuguese adults

ABSTRACT: BACKGROUND: There is scarce evidence regarding the association between diet and metabolic syndrome (MetS) in Portuguese population. We aim to evaluate the association between a posteriori dietary patterns (DPs) and MetS and its features. METHODS: Using random digit dialing, a sample of 2167 adults was selected between 1999 and 2003, in Porto. During a face-to-face interview, a questionnaire was applied, anthropometric measures were taken, blood pressure measured and a fasting blood sample collected. Diet was assessed using a validated food frequency questionnaire, and four DPs were identified in each sex by multivariate finite mixture models. RESULTS: After adjustment for age and daily energy intake, comparing to the "healthy" DP, women with the "low fruit and vegetables" DP had a higher odds of high waist circumference (OR = 1.88 95% CI 1.17-3.01) and low HDL-cholesterol (OR = 1.78 95% IC 1.12-2.82) and women in the "red meat and alcohol" DP had higher odds of high waist circumference (OR = 1.45 95% CI 1.01-2.07) and of MetS (OR = 1.57 95% CI 1.07-2.29); men with the "fish" DP had a higher odds of high triglycerides (OR = 1.57 95% CI 1.05-2.35). After further adjustments (education, physical activity, smoking, alcohol drinking, BMI, and menopausal status) no significant associations remained. CONCLUSIONS: Four distinct DPs were identified in a community sample of Portuguese adults and there was no association with the prevalence of MetS.     

Surface decorated platinum carbonyl clusters

Four molecular Pt-carbonyl clusters decorated by Cd-Br fragments, i.e., [Pt(13)(CO)(12){Cd(5)(μ-Br)(5)Br(2)(dmf)(3)}(2)](2-) (1), [Pt(19)(CO)(17){Cd(5)(μ-Br)(5)Br(3)(Me(2)CO)(2)}{Cd(5)(μ-Br)(5)Br(Me(2)CO)(4)}](2-) (2), [H(2)Pt(26)(CO)(20)(CdBr)(12)](8-) (3) and [H(4)Pt(26)(CO)(20)(CdBr)(12)(PtBr)(x)](6-) (4) (x = 0-2), have been obtained from the reactions between [Pt(3n)(CO)(6n)](2-) (n = 2-6) and CdBr(2)·H(2)O in dmf at 120 °C. The structures of these molecular clusters with diameters of 1.5-2 nm have been determined by X-ray crystallography. Both 1 and 2 are composed of icosahedral or bis-icosahedral Pt-CO cores decorated on the surface by Cd-Br motifs, whereas 3 and 4 display a cubic close packed Pt(26)Cd(12) metal frame decorated by CO and Br ligands. An oversimplified and unifying approach to interpret the electron count of these surface decorated platinum carbonyl clusters is suggested, and extended to other low-valent organometallic clusters and Au-thiolate nanoclusters.     

Synthesis and characterization of a titanium phosphate-tellurite glass for Faraday rotators

This work is focused on investigation of thermal, structural, optical, magnetic, and magneto-optical properties of novel titanium phosphate-tellurite glass applied as Faraday rotators. The glass belonging to the system 35Li₂O–10Al₂O₃–5TiO₂–45P₂O₅–5TeO₂ was prepared by a nonconventional wet route of raw materials processing, followed by melting-quenching-annealing steps. Some important physical properties of the investigated glass have been measured and calculated, providing knowledge related to glass compactness, electronic structure, glass forming capability, etc. XRD analysis evidenced an amorphous network structure of the investigated glass. The optical absorption in the Vis domain is mainly due to Ti³⁺ ions and Te₂ clusters formed during the glass melting process. A relatively low optical absorption is noticed over 600 nm that activates a significant Faraday magneto-optical effect. Photoluminescence bands in the blue, red, and infrared domains are observed, caused by Te₂ clusters formed during the glass melting process. The magnetization in dependency on applied magnetic field reveals a complex behavior of the glass, depending on temperature. Thus, it is found a ferromagnetic behavior up to 2000 Oe, a paramagnetic component up to 40 000 Oe, followed by a diamagnetic one over 40 000 Oe. Faraday rotation angle and Verdet constant values in the visible domain are correlated with the reduced TeO₂ content of the glass.     

The Impact of [C16Pyr][Amp] on the Aggressiveness in Breast and Prostate Cancer Cell Lines

Breast (BrCa) and prostate (PCa) cancers are the most common malignancies in women and men, respectively. The available therapeutic options for these tumors are still not curative and have severe side effects. Therefore, there is an urgent need for more effective antineoplastic agents. Herein, BrCa, PCa, and benign cell lines were treated with two ionic liquids and two quinoxalines and functional experiments were performed—namely cell viability, apoptosis, cytotoxicity, and colony formation assays. At the molecular level, an array of gene expressions encompassing several molecular pathways were used to explore the impact of treatment on gene expression. Although both quinoxalines and the ionic liquid [C2OHMIM][Amp] did not show any effect on the BrCa and PCa cell lines, [C16Pyr][Amp] significantly decreased cell viability and colony formation ability, while it increased the apoptosis levels of all cell lines. Importantly, [C16Pyr][Amp] was found to be more selective for cancer cells and less toxic than cisplatin. At the molecular level, this ionic liquid was also associated with reduced expression levels of CPT2, LDHA, MCM2, and SKP2, in both BrCa and PCa cell lines. Hence, [C16Pyr][Amp] was shown to be a promising anticancer therapeutic agent for BrCa and PCa cell lines.