Optical separation of mechanical strain from charge doping in graphene

Because of its superior stretchability, graphene exhibits rich structural deformation behaviours and its strain engineering has proven useful in modifying its electronic and magnetic properties. Despite the strain-sensitivity of the Raman G and 2D modes, the optical characterization of the native strain in graphene on silica substrates has been hampered by excess charges interfering with both modes. Here we show that the effects of strain and charges can be optically separated from each other by correlation analysis of the two modes, enabling simple quantification of both. Graphene with in-plane strain randomly occurring between -0.2% and 0.4% undergoes modest compression (-0.3%) and significant hole doping on thermal treatments. This study suggests that substrate-mediated mechanical strain is a ubiquitous phenomenon in two-dimensional materials. The proposed analysis will be of great use in characterizing graphene-based materials and devices.open11302307Nsciescopu

소아청소년 대사증후군

Background: Metabolic syndrome is a serious condition associated with multiple diseases. The prevalence of metabolic syndrome is increasing caused by an increase in obesity rates among children and adolescents. Current Concepts: Owing to the various definitions used, there is lack of consensus regarding the diagnostic criteria for metabolic syndrome in children and adolescents. Although the exact pathogenesis remains unclear, insulin resistance and subsequent inflammation are key mechanistic contributors. Metabolic syndrome is characterized by overweight and obesity accompanied by abnormalities in glucose metabolism, dyslipidemia, and hypertension and is associated with other conditions such as fatty liver, polycystic ovary syndrome, and a pro-inflammatory state. Prevention and management of metabolic syndrome can be achieved through lifestyle modifications, behavioral interventions, pharmacotherapy, and surgical interventions. Discussion and Conclusion: Childhood and adolescent obesity serves as a risk factor for metabolic syndrome during later life. Early identification and intervention are important to prevent the progression of metabolic syndrome. Clinicians must identify at-risk children and adolescents and provide guidance for the prevention and management of metabolic syndrome

Genetic factors in precocious puberty

Pubertal onset is known to result from reactivation of the hypothalamic-pituitary-gonadal (HPG) axis, which is controlled by complex interactions of genetic and nongenetic factors. Most cases of precocious puberty (PP) are diagnosed as central PP (CPP), defined as premature activation of the HPG axis. The cause of CPP in most girls is not identifiable and, thus, referred to as idiopathic CPP (ICPP), whereas boys are more likely to have an organic lesion in the brain. ICPP has a genetic background, as supported by studies showing that maternal age at menarche is associated with pubertal timing in their offspring. A gain of expression in the kisspeptin gene (KISS1), gain-of-function mutation in the kisspeptin receptor gene (KISS1R), loss-of-function mutation in makorin ring finger protein 3 (MKRN3), and loss-of-function mutations in the delta-like homolog 1 gene (DLK1) have been associated with ICPP. Other genes, such as gamma-aminobutyric acid receptor subunit alpha-1 (GABRA1), lin-28 homolog B (LIN28B), neuropeptide Y (NPYR), tachykinin 3 (TAC3), and tachykinin receptor 3 (TACR3), have been implicated in the progression of ICPP, although their relationships require elucidation. Environmental and socioeconomic factors may also be correlated with ICPP. In the progression of CPP, epigenetic factors such as DNA methylation, histone posttranslational modifications, and noncoding ribonucleic acids may mediate the relationship between genetic and environmental factors. CPP is correlated with short- and long-term adverse health outcomes, which forms the rationale for research focusing on understanding its genetic and nongenetic factors

Treatment of congenital hypogonadotropic hypo-gonadism in male patients

Congenital hypogonadotropic hypogonadism (CHH) is characterized by complete or partial failure of pubertal development because of inadequate secretion of gonadotropic hormones. CHH consists of hypogonadotropic hypogonadism with anosmia or hyposmia, Kallmann syndrome, and the normosmic variation normosmic idiopathic hypogonadotropic hypogonadism. CHH is one of the few treatable diseases of male infertility, although men with primary testicular dysfunction have irreversibly diminished spermatogenic capacity. The approach to CHH treatment is determined by goals such as developing virilization or inducing fertility. This review focuses on the current knowledge of therapeutic modalities for inducing puberty and fertility in men with CHH

Self-activated ultrahigh chemosensitivity of oxide thin film nanostructures for transparent sensors

One of the top design priorities for semiconductor chemical sensors is developing simple, low-cost, sensitive and reliable sensors to be built in handheld devices. However, the need to implement heating elements in sensor devices, and the resulting high power consumption, remains a major obstacle for the realization of miniaturized and integrated chemoresistive thin film sensors based on metal oxides. Here we demonstrate structurally simple but extremely efficient all oxide chemoresistive sensors with similar to 90% transmittance at visible wavelengths. Highly effective self-activation in anisotropically self-assembled nanocolumnar tungsten oxide thin films on glass substrate with indium-tin oxide electrodes enables ultrahigh response to nitrogen dioxide and volatile organic compounds with detection limits down to parts per trillion levels and power consumption less than 0.2 microwatts. Beyond the sensing performance, high transparency at visible wavelengths creates opportunities for their use in transparent electronic circuitry and optoelectronic devices with avenues for further functional convergence.open181

Updated reference ranges for aminotransferase levels of Korean children and young adolescents based on the risk factors for metabolic syndrome

We investigated the reference values of liver enzymes based on cardiometabolic risks among children and adolescents using the Korea National Health and Nutrition Examination Survey. A total of 8091 subjects aged 10-18 years were included from the data from 2007-2017. Overall, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and the AST/ALT ratio varied with sex and age. AST levels tended to decrease with age, but ALT levels had a U-shaped curve, which resulted in a gradual increase in the AST/ALT ratio after age 13. The prevalence of MetS was strongly associated with elevated AST or ALT and a decreased AST/ALT ratio. The prevalence ratios of the development of MetS were also elevated in groups with high levels of AST and ALT and a low AST/ALT ratio. Particularly in the combined ALT and AST/ALT analyses, borderline-high levels also showed a high prevalence ratio of MetS. Liver enzymes were also involved in the increase in the adjusted mean values for each risk factor for MetS. Here, we provided updated reference values for liver enzymes based on the analysis between population-based data and cardiometabolic risk factors; AST, ALT and the AST/ALT ratio might be useful in the early diagnosis and treatment of MetS

Positive Associations between Body Mass Index and Hematological Parameters, Including RBCs, WBCs, and Platelet Counts, in Korean Children and Adolescents

We conducted this study to investigate the associations between hematological parameters and obesity in children and adolescents. The levels of hematological parameters (including white blood cells [WBCs], red blood cells [RBCs], hemoglobin [Hb], hematocrit [Hct], and platelets) of 7997 participants (4259 boys and 3738 girls) aged 10-18 years were recorded. The parameters were compared among participants with normal weight, overweight, and obesity. Significantly higher mean levels of WBCs (7.16 vs. 6.16 x 103/mm(3), p < 0.001), RBCs (4.90 vs. 4.82 x 106/mm(3), p < 0.001), Hb (14.07 vs. 13.99 g/dL, p < 0.05), Hct (42.31 vs. 41.91%, p < 0.001), and platelets (311.87 vs. 282.66 x 103/mm(3), p < 0.001) were found in the obese than normal weight group, respectively, after adjusting for body mass index (BMI) and sex. BMI SDS had significant positive associations with the levels of WBCs (beta = 0.275, p < 0.001), RBCs (beta = 0.028, p < 0.001), Hb (beta = 0.034, p < 0.001), Hct (beta = 0.152, p < 0.001), and platelets (beta = 8.372, p < 0.001) after adjusting for age, sex, and socioeconomic factors in a multiple linear regression analysis. A higher BMI was associated with elevated WBC, RBC, Hb, Hct, and platelet counts in children and adolescents. Because higher levels of hematological parameters are potential risk factors for obesity-related diseases, hematological parameters should be evaluated in obese children and adolescents

Hemoglobin and hematocrit levels are positively associated with blood pressure in children and adolescents 10 to 18 years old

To investigate the associations between hemoglobin (Hb) concentration and hematocrit (Hct), and blood pressure (BP) in children and adolescents. The study population consisted of 7950 subjects total (4229 boys and 3721 girls) aged 10–18 years who participated in the Korea National Health and Nutrition Examination Surveys conducted between 2007 and 2017. The prevalence of hypertension was 19.19% (21.51% for boys and 16.5% for girls) among the study population, and the prevalence of obesity was 9.59% (10.5% for boys and 8.6% for girls). Hb count and Hct tended to increase with the degree of obesity and BP elevation. Systolic BP (SBP) and diastolic BP (DBP) positively correlated with Hb count and Hct in both sexes. Following multiple linear regression analysis, Hb count and Hct presented a positive association with SBP and DBP after adjusting for age, BMI SDS, alcohol consumption, smoking status, physical activity, rural residence, household income, diagnosis of T2DM, hypertension, and dyslipidemia. Hb count and Hct were positively associated with SBP and DBP in children and adolescents 10–18 years old