Background: Dyslipidemias in childhood increase the risk of cardiovascular events in adult life. Aim: To evaluate the prevalence of dyslipidemia and risk of atherogenicity based in the atherogenic index of plasma (AIP) in a sample of school children and adolescents. Material and Methods: Cross-sectional study of 208 children aged 10.4 ± 1.0 years (107 women). Demographic data were obtained, and a clinical evaluation was conducted, including pubertal development according to Tanner and anthropometric parameters. A fasting blood sample was obtained to measure total cholesterol (CT), HDL cholesterol (cHDL) and triglycerides (TG), glucose and insulin. LDL cholesterol (cLDL), Non-HDL cholesterol and the indices CT/cHDL, cLDL/cHDL and AIP (log[TG/cHDL]) were calculated. Risk categories according to AIP for the pediatric population were also determined (low: AIP < 0.11, intermediate: AIP 0.11-0.21, high: AIP > 0.21). Results: Thirty eight percent of participants had dyslipidemia, without differences by gender and pubertal development. The frequency of dyslipidemia was significantly higher in children with obesity (54%, p < 0.01) and a waist circumference over percentile 90 (61%; p < 0.01). The later conditions had also higher CT/cHDL, cLDL/cHDL and AIP. According to AIP, 54% of children had a high atherogenicity risk along with alterations in anthropometric parameters and insulin resistance. All anthropometric and insulin resistance parameters were significantly correlated with the AIP. Conclusions: There is a high prevalence of dyslipidemia in the studied population, which is associated with an increased cardiometabolic risk. The indices of atherogenicity and particularly AIP are correlated with nutritional status, abdominal obesity and parameters of insulin resistance.

Background: Childhood and adolescent obesity is a major public health problem in Chile. Aim: To characterize cardiometabolic risk factors in a population of schoolchildren from Carahue, Chile. Material and Methods: Cross-sectional assessment of 208 children aged 10.4 ± 1.0 years (106 women). A clinical evaluation was carried out including pubertal development according to Tanner and anthropometric parameters. A fasting blood sample was obtained to measure glucose, insulin and lipid profile. HOMA-IR and Quicki indices were calculated. Insulin resistance (IR) was established according to Burrows criteria and Barja criteria, previously proposed for the Chilean pediatric population. The metabolic syndrome (MetS) was established using the modified Cook criteria. Results: Thirty eight percent of children had overweight and 33.1% obesity. MetS was only observed in obese subjects and the frequency in this subgroup was 38%. The prevalence of IR was 51% according to the Burrows criteria and 19% according to Barja criteria. It was more common in participants who were overweight, obese or had abdominal obesity. Children with insulin resistance according to Barja criteria, had worse anthropometric measures than their counterparts without resistance. When Burrows criteria was used, no differences in anthropometric measures were observed between participants with or without resistance. The frequency of MetS was 26 and 18% in children with insulin resistance according to Barja and Burrows criteria, respectively. Insulin levels and insulin sensitivity indexes were positively correlated with anthropometric parameters. Conclusions: There was a high prevalence of overweight, obesity and MetS in these participants. Our results suggest that the IR criteria according to Barja allows to identify cases with higher metabolic risk.

The solid solutions Cu2Fe1-X CoX SnS4, with stannite-type structure are stable up to about 800°C. The electrical properties of the Cu2Fe0.4Co0.6SnS4 ceramic were investigated by complex impedance. The real and imaginary dielectric permittivity dependence with the temperature were measured between 10kHz and 1 MHz in temperature range 77-280K, finding that the ceramic present the characteristics behavior of a dielectric relaxation between 100 and 250 K, with a maximum at approximately 200 K. The electric permittivity found has orders of magnitude between 10² and 10³. A space charge polarization mechanism is suggested to explain the observed electric relaxation.

Este trabalho relata um estudo sistemático do comportamento estrutural e elétrico de três fases ternárias do sistema Ta xMo1-xS2 (x = 0,55, 0,75 e 0,90) e de seus compostos de intercalação resultantes das inserções química e eletroquímica de lítio, assim como das intercalações de piridina e poli(óxido de etileno). As três fases foram preparadas pela reação direta de seus elementos constituintes, sem qualquer outro aditivo, a 900 ºC em atmosfera inerte. Os compostos resultantes foram caracterizados por meio de difratometria de raios X de pó (XRD), análises termogravimétrica e térmica diferencial (TGA/DTA), fluorescência de raios X por dispersão de energia (EDX) e microscopia eletrônica de varredura com emissão de campo (FE-SEM). A condutividade elétrica dos diferentes compostos preparados foi medida no intervalo de temperatura 1,5-300 K utilizando o método convencional de sonda de quatro pontas van der Pauw na presença de um campo magnético de 9 T para verificar a ocorrência do fenômeno de magnetoresistividade.

This work reports a systematic study of the structural and electrical behavior of three ternary phases of the Ta xMo1-xS2 system (x = 0.55, 0.75 and 0.90) and their intercalation compounds resulting from both chemical and electrochemical lithium insertions, as well as from pyridine and poly(ethylene oxide) intercalations. The three ternary phases were prepared by direct reaction of their constituting elements, without any other additive, at 900 ºC in inert atmosphere. The resulting compounds were characterized by means of X-ray powder diffractometry (XRD), thermogravimetric and differential thermal (TGA/DTA) analyses, energy dispersive X-ray fluorescence (EDX) and field emission-scanning electron microscopy (FE-SEM). The electrical conductivity of the different products was measured in the 1.5-300 K temperature range using the conventional four probe van der Pauw method in the presence of a 9 T magnetic field in order to verify the occurrence of magnetoresistivity phenomena.

O tiofosfato quaternário de metal alcalino e terra rara K4Sm2[PS4]2[P2S6] foi sintetizado pelo método cerâmico e caracterizado por difratometria de raios X de pó (XRD), microscopia eletrônica de varredura com microanálise de raios X (SEM-EDX), medidas de impedância eletroquímica e medidas magnéticas. A estrutura cristalina consiste de camadas de ²∞Sm2[PS4]2[P2S6]4- separadas por cátions K+. As medidas de condutividade elétrica indicam que o composto é um semicondutor com uma resistividade de 1,0 x 10(11) Ω cm. O momento magnético, obtido a partir de χ-1 versus T a baixa temperatura, é igual a 0,57 μB.

The quaternary alkali metal, rare earth thiophosphate phase K4Sm2[PS4]2[P2S6] was synthesized by ceramic method and characterized by powder X-ray diffraction (XRD), SEM-EDX scanning electron microscope-microprobe analyses, electrochemical impedance and magnetic measurements. The crystal structure consists of layers of ²∞Sm2[PS4]2[P2S6]4- separated by K+ cations. The electrical conductivity measurements indicate that the compound is a semiconductor with a resistivity of 1.0 x10(11) Ω cm. The magnetic moment, evaluated from χ-1 versus T at low temperature is 0.57 µB.

The intercalation compounds Li0,43(PEO)2.4(H2O)1.4K0.57BiP2S6 and Li0.38(PEO)2.1(H2O)1.6K0.62SbP2S6 have been synthesized by the insertion of polyethylene oxide PEO in LiKMP2S6 (M=Bi, Sb), that contained Li+ and K+ exchangeable cations in their interlayer space. The polymer PEO is able to associate interlayer Li+ cation modifying the ionic conductivity of pristine phases. These intercalation compounds constitute a new family of intercalates in the thiophosphate of Bi and Sb with Polyethylene oxide as guest species. They have been characterized by powder X-ray diffraction, FTIR-Raman, DTA/TGA analysis and electrical conductivity measurements. The studied nanocomposite shows values of electrical conductivity (σi) of about 10-6 Ω-1 cm-1 at room temperature.

The structure of the 1: 2 adduct of hexamethylenetetramine and thiourea was reanalyzed reinterpreting X-ray diffraction data and providing additional IR and NMR spectroscopic features. The product is thus described as supramolecular commensurate host-guest complex corresponding to the intercalation of hexamethylenetetramine in a layered thiourea matrix. FT-IR spectra evidence a simultaneous strengthening of both C-N and C-S bonds, that appearing as a pattern characteristic for described layered thiourea matrix. 13CP MAS-NMR spectra of the intercalated hexamethylenetetramine is essentially determined by nuclear dipolar magnetic interactions and host-guest chemical interactions arising from 13C-14N residual dipolar interaction not averaged to zero by MAS-NMR and from the magnetic non-equivalence of the guest carbon atoms caused by the hydrogen bonding interaction with the thiourea matrix