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The COllaborative project of Development of Anthropometrical measures in Twins (CODATwins) project is a large international collaborative effort to analyze individual-level phenotype data from twins in multiple cohorts from different environments. The main objective is to study factors that modify genetic and environmental variation of height, body mass index (BMI, kg/m2) and size at birth, and additionally to address other research questions such as long-term consequences of birth size. The project started in 2013 and is open to all twin projects in the world having height and weight measures on twins with information on zygosity. Thus far, 54 twin projects from 24 countries have provided individual-level data. The CODATwins database includes 489,981 twin individuals (228,635 complete twin pairs). Since many twin cohorts have collected longitudinal data, there is a total of 1,049,785 height and weight observations. For many cohorts, we also have information on birth weight and length, own smoking behavior and own or parental education. We found that the heritability estimates of height and BMI systematically changed from infancy to old age. Remarkably, only minor differences in the heritability estimates were found across cultural–geographic regions, measurement time and birth cohort for height and BMI. In addition to genetic epidemiological studies, we looked at associations of height and BMI with education, birth weight and smoking status. Within-family analyses examined differences within same-sex and opposite-sex dizygotic twins in birth size and later development. The CODATwins project demonstrates the feasibility and value of international collaboration to address gene-by-exposure interactions that require large sample sizes and address the effects of different exposures across time, geographical regions and socioeconomic status.
Whether monozygotic (MZ) and dizygotic (DZ) twins differ from each other in a variety of phenotypes is important for genetic twin modeling and for inferences made from twin studies in general. We analyzed whether there were differences in individual, maternal and paternal education between MZ and DZ twins in a large pooled dataset. Information was gathered on individual education for 218,362 adult twins from 27 twin cohorts (53% females; 39% MZ twins), and on maternal and paternal education for 147,315 and 143,056 twins respectively, from 28 twin cohorts (52% females; 38% MZ twins). Together, we had information on individual or parental education from 42 twin cohorts representing 19 countries. The original education classifications were transformed to education years and analyzed using linear regression models. Overall, MZ males had 0.26 (95% CI [0.21, 0.31]) years and MZ females 0.17 (95% CI [0.12, 0.21]) years longer education than DZ twins. The zygosity difference became smaller in more recent birth cohorts for both males and females. Parental education was somewhat longer for fathers of DZ twins in cohorts born in 1990–1999 (0.16 years, 95% CI [0.08, 0.25]) and 2000 or later (0.11 years, 95% CI [0.00, 0.22]), compared with fathers of MZ twins. The results show that the years of both individual and parental education are largely similar in MZ and DZ twins. We suggest that the socio-economic differences between MZ and DZ twins are so small that inferences based upon genetic modeling of twin data are not affected.
A new approach is proposed to analyze Bremsstrahlung X-rays that are emitted from laser-produced plasmas (LPP) and are measured by a stack type spectrometer. This new method is based on a spectral tomographic reconstruction concept with the variational principle for optimization, without referring to the electron energy distribution of a plasma. This approach is applied to the analysis of some experimental data obtained at a few major laser facilities to demonstrate the applicability of the method. Slope temperatures of X-rays from LPP are determined with a two-temperature model, showing different spectral characteristics of X-rays depending on laser properties used in the experiments.
Depression is common after acute coronary syndrome (ACS) with adverse effects on prognosis. There is little evidence on whether depression treatment improves quality of life (QoL) in ACS patients. The aim of this study was to investigate the effects of co-morbid depression and its treatment on QoL in ACS.
In total, 1152 patients were recruited at baseline, 2–14 weeks after a confirmed ACS episode, and 828 were followed 1 year thereafter. Of 446 baseline participants with co-morbid depressive disorders, 300 were randomized to a 24-week double blind trial of escitalopram or placebo, while the remaining 146 received medical treatment only (MTO). QoL was measured by the World Health Organization Quality of Life –Abbreviated form (WHOQOL-BREF).
At baseline, QoL was significantly lower in patients with co-morbid depressive disorder than those without. QoL improvement was significantly greater in those receiving escitalopram than those receiving placebo over the 24-week treatment period. In the 1-year follow-up, the better outcomes associated with escitalopram remained evident against both placebo and MTO.
Depression was significantly associated with worse QoL even in patients with recently developed ACS. Depression treatment was associated with QoL improvement in ACS patients in the 24-week treatment period, the effects of which extended to 1 year.
In February 2012, an outbreak of gastroenteritis was reported in school A; a successive outbreak was reported at school B. A retrospective cohort study conducted in school A showed that seasoned green seaweed with radishes (relative risk 7·9, 95% confidence interval 1·1–56·2) was significantly associated with illness. Similarly, a case-control study of students at school B showed that cases were 5·1 (95% confidence interval 1·1–24·8) times more likely to have eaten seasoned green seaweed with pears. Multiple norovirus genotypes were detected in samples from students in schools A and B. Norovirus GII.6 isolated from schools A and B were phylogenetically indistinguishable. Green seaweed was supplied by company X, and norovirus GII.4 was isolated from samples of green seaweed. Green seaweed was assumed to be linked to these outbreaks. To our knowledge, this is the first reported norovirus outbreak associated with green seaweed.
We report a simple synthesis technique to attached poly(N-isopropylacrylamide) on magnetic nanoparticles. Fe3O4 magnetic nanoparticles were prepared using co-precipitation method. Nearly monodisperse nanoparticles were separated by terminating surface of Fe3O4 with dopamine followed by careful centrifugation and decantation. NHS/EDC coupling chemistry was employed to attached the carboxylic acid terminated poly(N-isopropylacrylamide) to amine end of dopamine on surface of the magnetic particles. Analysis of the polymer brush layers was conducted using UV-Vis spectroscopy, ATR−FTIR, and Transmission electron microscopy techniques. The magnetic property was investigated using direct current superconducting quantum interference device (DC-SQUID) method.
Ultra-high molecular weight polyethylene/graphite nanocomposites were prepared by high-energy cryogenic milling followed by syntering. Microstructure changes shows that graphite was reduced to graphite nanoplatelets by high-energy cryomilling and partial exfoliation of graphite to few layered graphene nanoplatelets occurred in a small extent. The resulting nanocomposites revealed high electrical conductivity and good mechanical performance. Thermal characterization of the nanocomposites was also carried out by differential scanning calorimetry.
In this work Carrageenan type κ was used as electrosteric stabilizer in order to prepare a biocompatible colloidal dispersion of novel metal nanoparticles. Gold and silver nanoparticles were synthesized by reducing the metal precursor using sodium borohydride in presence of Carrageenan type κ. The growth mechanism of metal nanoparticles and stabilization behavior by Carrageenan type κ was analyzed by UV-Vis spectroscopy and transmission electron microscopy. The morphology and particle size distribution were also studied as a function of reaction parameters and the particle size was dependent of the pH of the reaction media. The Ag nanoparticles with sphere-like morphology and average size of 10 nm were obtained. The morphology of Au nanoparticles was strongly affected by the pH value resulting in particles with snake-like morphology at alkaline conditions. The UV-Vis spectra showed that Ag nanoparticles were highly stable at alkaline conditions and for long period of time. Au nanoparticles dispersion showed a better stability for long period of time at acidic conditions. The nanoparticles dispersion electrosterically stabilized were used to prepare hydrogels by poured into a plastic mold and frozen with liquid nitrogen and then lyophilized. The morphology and thermal stability of resulting composites were analyzed by using scanning electronic microscopy and differential scanning calorimetry respectively. The degradation temperature of Carrageenan type κ was increased due to the presence of metal nanoparticles.
Nanocomposites of gold nanoparticles (AuNPs) embedded in polyaniline fibers have been fabricated using a one-pot synthesis approach and in-situ polymerization. By using a combination of inorganic acids (e.g. HCl) and camphorsulfonic acid, polyaniline nanostructured fibers of high aspect ratio with diameters of 150 ± 50 nm and several micrometers in length were obtained. These fibers afforded high electrical conductivity of 4.2 ± 0.5 S/cm. Encapsulation of the AuNPs in the polyaniline fibers afforded nanocomposites with high electrical conductivity and dielectric constant of 34.0 ± 0.5 S/cm and 65.3 ± 5 respectively. The morphology of these materials was analyzed using SEM and HRTEM and electronic properties were analyzed using UV-Vis spectroscopy.
We have investigated BisGMA-TEGDMA dental composites with varying mass fractions of hydroxyapatite and silica filler. Commercially available dental composites with 60% silica filler were synthesized in the presence of nanometer-sized hydroxyapatite crystals. We have compared the mechanical properties of BisGMA-TEGDMA samples filled with silica only and those filled with silica and hydroxyapatite particles. We report on hardness as a function of crystalline content as determined by nanoindentation and microindentation.
The photodegradation of polypropylene (PP)/ZnO composites at different concentrations was evaluated under solar simulated exposure of respective nanocomposite films. Nanocomposites were prepared by solid mixing using a cryogenic mill, and then films were prepared by compression molding. All films showed a good dispersion of ZnO nanoparticles without affect considerably the optical properties of the films. The films were exposed in a solar simulation chamber under three xenon arc lamps with a 340nm filter. Degradation of PP/ZnO nanocomposite films was monitored by formation of oxidative groups and changes on surface microstructure. FTIR results showed that oxidation groups in nanocomposites films increased by using cuasi-spherical ZnO nanoparticles.
Shape memory nanocomposites were produced following a simple one-step synthesis route initiated by a series of molar mixtures of POSS thiol nanocages and pentaerythritol tetrakis (3mercaptopropionate), and a diacrylate polycaprolactone (PCL) with Mn=3,000 g/mol. Simultaneous wide- and small- angle X ray scattering (WAXS/SAXS), differential scanning calorimetry (DSC) and atomic force microscopy (AFM) experiments were carried out and results were correlated on microstructure. Molecular identification was performed by Fourier transformed infrared (FTIR-ATR). Thermomechanical shape memory cycles revealed that the nanocomposites achieved excellent shape recovery (99%) and shape fixity (100%) parameters. Dynamic mechanical analysis showed that elastomeric modulus decrease in function of the POSS thiol molar concentration and this result is correlated with the decrease in average crosslink density (ν). WAXS studies revealed orthorhombic crystallites for PCL combined with an amorphous POSS phase when the molar concentration of POSS was low (2.5%, 5%, 10%). However, increasing the molar concentration of POSS thiol until 20%, a broad and weak reflection centered around 2θ =7.9° which corresponded to imperfect POSS crystals. At the nanoscale, SAXS analysis showed lamellar nanostructure formation for all POSS/polycaprolactone crosslinked networks. Strikingly, induced anisotropic orientation of polycaprolactone lamellar nanostructure was observed when the concentration of POSS increased to 10 and 20 mol%.
Polystyrene (PS), polymethyl-methacrylate (PMMA) and multi-walled carbon nanotubes (MWNT) were used to fabricate conductive nanocomposites using various mixing methods, followed by compression molding to analyze their electrical properties. The main objective of this research project was to evaluate how using different mixing techniques alter the composite microstructure and hence the properties of the resultant composite material. Three fabrication techniques were selected to be investigated: mechanical mixing, melt-mixing, and solution mixing. The concentration of the fillers was kept constant at 2 wt% MWNT to simplify comparisons. After mixing, the composite mixtures were compression molded at the same temperature of 180°C. It was found that each mixing method yielded uniquely different AC conductivity profiles which can be attributed to how the fabrication method used affected the arrangement of the CNTs in the composite structure. This newfound control of the electrical properties of the composite materials could definitely be useful to researchers because one can choose the proper fabrication technique based on what properties are desired.
Nanocomposites of polysaccharide matrices, chitosan-starch and carboxymethyl cellulose-starch reinforced with graphene oxide and graphene grafted with keratin were developed. Composites films had been prepared for the casting/solvent evaporation method. The nanocomposites of chitosan/starch matrix improved substantially their mechanical properties with respect to the film without reinforcing, obtaining an increase of 929 % in the storage modulus (E’ 35°C) with only 0.5 wt% of graphene oxide and outstanding increments in E’ at 150°C and 200°C when keratin grafted graphene oxide is incorporated (0.1 wt%). In contrast, the graphene oxide incorporated into the carboxymethyl cellulose-starch matrix tends to decrease the stiffness of the film behaving in opposite way to nanocomposite of chitosan/starch matrix.
Temperature-sensitive ferrogel prepared using Fe3O4 nanoparticles are characterized under varying temperature conditions. The nanoparticles were distributed in Nisopropylacrylamide (NIPAm) during their polymerization to form hydrogel. Particle distribution and agglomeration characteristics of the prepared ferrogels were investigated using ultra small angle x-ray scattering (USAXS) at various temperatures through the Lower Critical Solution Temperature (LCST). Transmission electron microscopy (TEM) was used to estimate the particle size distribution. The magnetic property was investigated using direct current superconducting quantum interference device (DC-SQUID) under hydrated conditions. The USAXS analysis showed an increase in the volume of particles without changing the agglomeration characteristics as the temperature is increased during the measurements. The ferrogel did not show any sedimentation or particle detachment from the gel under thermal cycling. Details of our results and analysis are presented.
The preparation of metal nanoparticles is a major research area in technical engineering due to their unusual properties, such as catalytic activity, novel electronic, optic and magnetic properties and biotechnology. Specially, silver has been used for years in the medical field for antimicrobial applications because it known for its antimicrobial properties and even has shown to prevent HIV binding to host cells. Common synthesis, chemical and physical methods using chemical reducing agent and organic solvent are not too suitable to have application to bioengineering because they should have associated environmental toxicity or biological hazards. Development of sustainable processes through green chemistry is attractive about the elimination or minimization of chemical waste. Here, we introduce the green method for preparation of silver nanoparticles using chitosan oligomer as both reducing and stabilizing agent in water. We expect that the use of environmentally benign solvent and chitosan oligomer to prepare silver nanoparticles offers numerous benefits and compatibility for pharmaceutical and biomedical applications.
The parameters influencing the formation of silver nanoparticles are reported. We used poly(vinyl alcohol) (PVA), maltose and silver nitrate as stabilizer, reductant and silver nanoparticles precursor, respectively. The formation of nanoparticles depended upon reaction temperature and pH of solution. The pH of solution controlled by HCl and NaOH. The reaction rate and amount of nanoparticles increase with increasing the reaction temperature. Also, formation of nanoparticles are influenced by pH. The size distribution and dispersion of Ag nanoparticles formed in PVA solution were observed by Transmission electron microscopy (TEM) and the reaction rate and amount of nanoparticles were characterized UV-vis spectrophotometer.
We have utilized wet-chemical etching of ellipsoidal silica nanoparticles to form silica nanoshells of a range of elliptical morphologies. The thicknesses of the silica ellipsoidal nanoshells are controlled through variation of synthesis conditions. A mechanism has been proposed to explain how the nanoshells are formed, and we have demonstrated that the porosity of the silica ellipsoid plays a role in the dissolution-regrowth process. We have also, via appropriate functionalization of the silica surface, coated the ellipsoidal nanoshells with Au nanoparticles.
Novel hydrogels composed of thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) and redox-responsive poly(ferrocenylsilane) (PFS) macromolecules were formed by photopolymerization. PFS chains bearing acrylate side groups were copolymerized with NIPAM and N,N’-methylenebisacrylamide in tetrahydrofuran in a predetermined ratio under ultraviolet light-emitting diode (UV-LED) irradiation at a wavelength of 365 nm, in the presence of a photoinitiator. Crosslinking occurred smoothly, providing homogeneous hydrogels. The equilibrium swelling ratio, rheology and morphology of these hybrid PNIPAM-PFS-based hydrogels were investigated. In-situ fabrication of silver nanoparticles inside the hydrogel network via reduction of silver nitrate by the PFS chains led to hydrogel composites. These composites showed strong antimicrobial activity while maintaining a high biocompatibility with cells.
In this paper we report about combining inkjet printing technology and self-assembly as a scalable manufacturing tool for spherical, well-ordered aggregates. The aggregates consist of a high number of ordered colloidal nanospheres arranged as ball-shaped structures. Applying inkjet printing based on the principle of droplet ejection the spherical aggregates can be deposited on various surfaces in dry environment and under ambient conditions. The aggregation of the nanospheres is independent of the surface energy of the substrate leading to the assumption that the main part of the assembly and aggregation process takes place in-flight .
By applying inkjet printing with an adapted control signal, small droplets of a water-based ink formulation containing monodisperse polystyrene nanoparticles are ejected out of the inkjet nozzles. The ejected droplets serve as a confined geometry for the nanospheres in the carrier liquid during evaporation. As a result, the particles form stable ball-shaped aggregates with hexagonal order. Due to the in-flight self-assembly of the nanospheres, our approach is suitable for any solid surface in dry environment and allows the deposition of the ball-shaped aggregates in appropriate patterns.