Modelling the growth of ZnO nanocombs based on the piezoelectric effect

In this work a model for the growth of ZnO nanocombs based on the piezoelectric character of ZnO is presented that explains the periodic growth of nanowire branches on the polar +(0001) surface of a ZnO nanobelt as a self catalytic growth process. In this model the perturbation and elasticity theory are applied to approximate the induced mechanical strain and piezoelectric potential distribution in the nanobelt under the growth kinetics. To implement a quantitative simulation of the periodic growth of ZnO nanobranches the induced piezoelectric charges in the ZnO nanostructure are calculated. These are responsible for the structural transformation from a nanobelt into a nanocomb. A comparison with nanocombs that are synthesized using the vapor-liquid-solid method shows good agreement between experimental and theoretical results

Bridging the Mid-Infrared-to-Telecom Gap with Silicon Nanophotonic Spectral Translation

Expanding far beyond traditional applications in optical interconnects at telecommunications wavelengths, the silicon nanophotonic integrated circuit platform has recently proven its merits for working with mid-infrared (mid-IR) optical signals in the 2-8 {\mu}m range. Mid-IR integrated optical systems are capable of addressing applications including industrial process and environmental monitoring, threat detection, medical diagnostics, and free-space communication. Rapid progress has led to the demonstration of various silicon components designed for the on-chip processing of mid-IR signals, including waveguides, vertical grating couplers, microcavities, and electrooptic modulators. Even so, a notable obstacle to the continued advancement of chip-scale systems is imposed by the narrow-bandgap semiconductors, such as InSb and HgCdTe, traditionally used to convert mid-IR photons to electrical currents. The cryogenic or multi-stage thermo-electric cooling required to suppress dark current noise, exponentially dependent upon the ratio Eg/kT, can limit the development of small, low-power, and low-cost integrated optical systems for the mid-IR. However, if the mid-IR optical signal could be spectrally translated to shorter wavelengths, for example within the near-infrared telecom band, photodetectors using wider bandgap semiconductors such as InGaAs or Ge could be used to eliminate prohibitive cooling requirements. Moreover, telecom band detectors typically perform with higher detectivity and faster response times when compared with their mid-IR counterparts. Here we address these challenges with a silicon-integrated approach to spectral translation, by employing efficient four-wave mixing (FWM) and large optical parametric gain in silicon nanophotonic wires

Organic Agriculture

Consumers are increasingly aware of the health- and safety-related implications of the food which they can buy in the market. At the same time, households have become more aware of their environmental responsibilities. Regarding the production of food, a crucial and multifunctional role is played by agriculture. The way vegetables, fruits, and other crops are grown and how livestock is raised has an impact on the environment and landscape. Operations performed by farmers, such as water management, can be dangerous for the soil and the whole ecosystem. Consequently, there is a search for natural ways of sustaining the impact of agriculture on the environment. In this context, one of the most popular ideas is organic agriculture. In the literature on the subject, there are many concepts that some authors consider to be synonymous even as others argue that these terms are not interchangeable. There is, for example, "organic agriculture," "alternative agriculture," "sustainable agriculture," "ecological agriculture," "biological agriculture," "niche farming," "community-supported agriculture," and "integrated pest management." Very often, techniques and products related to organic agriculture are described by marketing experts with the use of abbreviations such as "bio" and "eco." Products with such markings and labels are increasingly popular in stores that often give them separate shelves for their sale. Despite the higher price compared to conventional products, they are increasingly sought by consumers. The entry examines the various impacts of organic agriculture with a view to these trends

Comprehensive Association Study of Type 2 Diabetes and Related Quantitative Traits With 222 Candidate Genes

OBJECTIVE—Type 2 diabetes is a common complex disorder with environmental and genetic components. We used a candidate gene–based approach to identify single nucleotide polymorphism (SNP) variants in 222 candidate genes that influence susceptibility to type 2 diabetes

The importance of maternal insulin resistance throughout pregnancy on neonatal adiposity

Background: Although previous studies evaluated the association of maternal health parameters with neonatal adiposity, little is known regarding the complexity of the relationships among different maternal health parameters throughout pregnancy and its impact on neonatal adiposity. Objectives: To evaluate the direct and indirect associations between maternal insulin resistance during pregnancy, in women with obesity, and neonatal adiposity. In addition, associations between maternal fasting glucose, triglycerides (TG), non-esterified fatty acids (NEFA), and neonatal adiposity were also assessed. Methods: This is a longitudinal, secondary analysis of the DALI study, an international project conducted in nine European countries with pregnant women with obesity. Maternal insulin resistance (HOMA-IR), fasting glucose, TG, and NEFA were measured three times during pregnancy (<20, 24-28, and 35-37 weeks of gestation). Offspring neonatal adiposity was estimated by the sum of four skinfolds. Structural equation modelling was conducted to evaluate the direct and indirect relationships among the variables of interest. Results: Data on 657 mother-infant pairs (50.7% boys) were analysed. Neonatal boys exhibited lower mean sum of skinfolds compared to girls (20.3 mm, 95% CI 19.7, 21.0 vs 21.5 mm, 95% CI 20.8, 22.2). In boys, maternal HOMA-IR at <20 weeks was directly associated with neonatal adiposity (β = 0.35 mm, 95% CI 0.01, 0.70). In girls, maternal HOMA-IR at 24-28 weeks was only indirectly associated with neonatal adiposity, which implies that this association was mediated via maternal HOMA-IR, glucose, triglycerides, and NEFA during pregnancy (β = 0.26 mm, 95% CI 0.08, 0.44). Conclusions: The timing of the role of maternal insulin resistance on neonatal adiposity depends on fetal sex. Although the association was time-dependent, maternal insulin resistance was associated with neonatal adiposity in both sexes