Interference tunable second harmonic generation for two-dimensional materials in layered structures.

We experimentally study the tunability of second harmonic generation (SHG) from a two-dimensional (2D) material in a 2D material/dielectric film/substrate layered structure. Such tunability arises from two interferences: one is between the incident fundamental light and its reflected light, and the other is between the upward second harmonic (SH) light and the reflected downward SH light. When both interferences are constructive, the SHG is maximally enhanced; it becomes attenuated if either of them is destructive. The maximal signal can be obtained when both interferences are perfectly constructive, which can be realized by choosing a highly reflective substrate and an appropriate thickness for a dielectric film that has a large difference in its refractive indices at the fundamental and the SH wavelengths. Our experiments demonstrate variations of three orders of magnitude in the SHG signals from a monolayer MoS2/TiO2/Ag layered structure.

The association between vitamin D levels and heart rate variability in patients with type 2 diabetes mellitus.

To assess the association between serum vitamin D levels and heart rate variability in patients with type 2 diabetes mellitus (T2DM). This study included 469 patients who were retrospective assessed for eligibility from Changzhou Second People's Hospital, Affiliated Nanjing Medical University, between March 2013 and June 2020. A total of 191 T2DM patients were recruited and divided into 3 groups. A total of 191 patients were recruited. A significant difference was noted among groups for HbA1c (P < .001), serum uric acid (P = .048), and urea nitrogen (P = .043). The Vitamin D level in deficiency, insufficiency, and sufficient was 23.17, 38.89, and 63.01 nmol/L, respectively. The insufficient group had lower levels of percentage of normal-to-normal intervals differing by more than 50 milliseconds, and the square root of the mean of the squares of the differences between adjacent normal-to-normal R peak-to-R-peak time intervals than the sufficient vitamin D group. Furthermore, patients in deficiency and insufficiency group were associated with high level of low frequency power/high frequency power as compared with sufficient vitamin D group. Finally, serum 25-hydroxyvitamin D (25(OH)D) levels were positively correlated with rMSSD (P = .002). This study found that low serum 25(OH)D levels were associated with reduced heart rate variability parameters in patients with T2DM.

Risk Factors of Ketosis in Obese Ketosis-Prone Diabetic Patients: A Case-Control Study.

INTRODUCTION: Different types of ketosis-prone obese diabetic patients are seen in the clinic. At present, the mechanism responsible for ketosis onset in these patients remains unclear, and we do not know how these patients should be optimally treated to prevent recurrent ketosis. Therefore, this study aims to investigate risk factors of ketosis in obese ketosis-prone diabetic (OB-KPD) patients. METHODS: In an observational case-control study, primary OB-KPD patients [body mass index (BMI) ≥ 28 kg/m2] were selected as the study group (OB-KPD group), and primary obese type 2 diabetes patients served as the control group (OB-T2DM group). Clinical diagnostic assessments of fasting plasma glucose (FPG), glycated hemoglobin (HbA1c), blood lipid, area under curve of serum C-peptide (AUCC-P) after steamed bread meal, insulin sensitivity index (ISI), ß-hydroxybutyric acid (ß-HB) and free fatty acid (FFA) vlaues of the subjects were collected. Subjects in the OB-KPD group were followed up for 1 year to determine the likelihood of insulin therapy cessation and whether ketosis recurred by assessing clinical chemistry parameters at 1-year follow-up. RESULTS: Seventy-five subjects were screened, of which 15 were not included in the study for several identified clinical reasons. On enrollment, the OB-KPD group displayed significantly higher FPG, HbA1c and FFA levels than the OB-T2DM group (p < 0.01), while AUCC-P and ISI values were significantly lower than in the OB-T2DM group (p < 0.01 and p = 0.03). Statistical analysis showed that increases in ß-HB in the OB-KPD group were associated with increased blood glucose and FFA and decreased AUCC-P and ISI values. Furthermore, decreases in AUCC-P were closely associated with increased blood glucose values. CONCLUSION: The occurrence of ketosis in ketosis-prone obese diabetic patients may be related to glucose and lipid metabolism disorders, increased insulin resistance and decreased ß-cell secretory functions. TRIAL REGISTRATION: This work was registered at the Chinese Clinical Trial Registry with trial registration identifier no. ChiCTR1900025909.

Telmisartan attenuates hydrogen peroxide-induced apoptosis in differentiated PC12 cells.

The present study investigated the protective actions of telmisartan, an angiotensin II type 1 receptor blocker (ARBs), against the cell apoptosis induced by exposure to hydrogen peroxide (H2O2) in differentiated PC12 cells. Preincubation of PC12 cells with telmisartan prevented H2O2-induced cytotoxicity as indicated by increased MTT (3,(4,5-dimethylthiazole-2-yl)2,5-diphenyl-tetrazolium bromide) reduction, decreased lactate dehydrogenase (LDH) release, and improved morphological changes. Hoechst 33,258 staining showed that telmisartan markedly reduced shrunken nuclei of the cells, and Western blot analysis indicated that telmisartan significantly attenuated caspase-3 activity, as indicated by decreased ratio of cleaved Caspase-3 to its precursor and increased ratio of Bcl-2/Bax. The present findings showed that telmisartan protected against cellular oxidative damages by inhibiting apoptotic response.

[The disease characteristics and risk factors of type 2 diabetes mellitus in pedigrees].

OBJECTIVE: To explore the characteristics and risk factors of type 2 diabetes mellitus (T2DM) onset in pedigrees. METHODS: A total of 865 subjects were screened and diagnosed by oral glucose tolerance test (OGTT) based on American Diabetes Association (ADA) criteria. Type 1 diabetes mellitus (T1DM), maturity onset diabetes of the young (MODY) and chondriosome diabetes were excluded by clinical features and laboratory test of insulin and autoantibodies including glutamic acid decarboxylase antibody, insular cellular antibody and insulin autoantibody. A total of 182 pedigrees of T2DM were obtained. RESULTS: No gender difference was found in the prevalence of T2DM (42.59% in male and 48.18% in female respectively, P > 0.05), nor was the newly diagnosed rate (9.89% in male and 11.82% in female, P > 0.05). The onset age was (63.3 ± 12.4) years old in the first generation [(64.4 ± 12.5) years in male and (62.3 ± 10.3) years in female], (47.1 ± 8.7) years old in the second generation [(48.2 ± 9.3) years in male and (46.1 ± 8.1) years in female], (29.6 ± 10.2) years old in the third generation [(28.9 ± 9.5) years in male and (30.0 ± 10.4) years in female]. Compared with normal glucose tolerance (NGT) subjects, newly diagnosed T2DM and impaired glucose regulation (IGR) subjects had higher prevalence of hypertension, hyperlipidemia and smoking but less physical activities. Statistical differences were shown in body weight five years before diagnosis, one years before diagnosis and at diagnosis in newly diagnosed T2DM [(68.4 ± 12.4) kg, (69.5 ± 11.0) kg and (69.1 ± 9.6) kg] and IGR [(66.1 ± 10.7) kg, (65.9 ± 10.7) kg and (65.7 ± 10.4) kg], when compared with NGT [(61.0 ± 10.2) kg, (59.5 ± 11.0) kg and (60.1 ± 10.4) kg, all P < 0.05]. The same results were obtained with waist circumference and waist-hip ratio [(4.1 ± 12.5) cm and 0.92 ± 0.36 in newly diagnosed T2DM while (89.1 ± 10.7) cm and 0.90 ± 0.64 in IGR], when compared with NGT [(82.5 ± 10.1) cm and 0.82 ± 0.25], all P < 0.05. CONCLUSIONS: No gender difference was found in the onset characteristics of T2DM. High prevalence of obesity, hypertension, hyperlipidemia and smoking with less physical activities were associated with T2DM.

[Relationship between polymorphism of urotensin II gene and type 2 diabetes in pedigrees].

OBJECTIVE: To investigate the association between a polymorphism (rs228648) of urotensin II (UT-II) gene and type 2 diabetes in pedigrees. METHODS: Patients and controls with/without familial history were enrolled in the same place. RESULTS: Carriers with AG or AA genotype from pedigrees had higher disease risk than those with GG genotype (OR=1.98, 95% CI:1.19-3.29,OR=2.46,95% CI:1.39-4.34), the frequency of A allele was higher in the patients from pedigrees than inner controls and patients who had no familial history (P=0.01). The frequency of A allele was higher in the inner controls than outer ones (P=0.001). The insulin resistance index, insulin sensitivity index and pancreatic secretion index of inner controls with AG genotype were higher than those with GG genotype (All P < 0.05). CONCLUSION: This polymorphism of UT-II gene might be a risk to type 2 diabetes, the insulin function of people from pedigrees is associated with the mutation.

[A study on risk factors among 125 type 2 diabetes mellitus with familial tendency].

OBJECTIVE: To study the risk factors regarding heredity and environment in familial incident type 2 diabetes mellitus (DM). METHODS: To compare the difference of environmental risk factors between type 2 DM, impaired glucose tolerance (IGT) and normal persons through study on familial information and environmental risk factors in 125 familial incident type 2 DM in-patients and out-patients from 1999 to 2001. Falconer was used to estimate heritability. Penrose was used to study the heredity damagers by polygene analysis. RESULTS: There was a significant constituent ratio diversity (P < 0.01) in triglyceride, body mass index, waist to hip ratio, hypertension history and physical activities history among 3 groups, while no significant diversity in blood lipids and history of coronary heart disease. 83.42% +/- 5.84% heritability of type 2 DM in 125 familial predigree indicated that dominant major gene might exist in these familiar pedigrees. Analysis of polygene in these groups showed type 2 DM might conform to the model of polygene heredity. CONCLUSION: This study suggested that type 2 DM had significant heritability and genetic heterogeneity, which generally appeared to be a disease of multi-factorial inheritance. Environmental risk factors, genetic factors and their interactions were due to type 2 DM.

[Study on the relationship between sulfonylurea receptor 1 gene polymorphism and type 2 diabetes mellitus].

To study whether the 3c/t polymorphism of the sulfonylurea receptor 1 (SUR1) gene exon16 increased the risk of type 2 diabetes mellitus in type 2 diabetes mellitus pedigrees in Han population in south area of China. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used in 46 type 2 diabetes mellitus pedigrees. The polymorphism in SUR1 was tested and analyzed by Mantel-Haenszel chi(2) test. Frequencies of SUR1-3c/t polymorphism had no significant difference between type 2 diabetes mellitus and normal relatives (genotypes chi(2)=3.224, P=0.199; frequency of allele chi(2)=1.250, P=0.264). In all subjects, type 2 diabetes mellitus and normal relatives, SUR1-3c/t genotypes were listed (cc: 29.3%, 30.2%, 28.3%; ct: 50.7%, 53.8%, 47.2%; tt: 20%, 16.0%, 24.5% respectively). The frequencies of c were 54.7%, 57.1% and 51.9% respectively. The frequency of c is lower than Han population in northern China. The results show that SUR1 exon16-3c/t polymorphism is not associated with type 2 diabetes mellitus in the population.

[Studies on genetic model in familial type 2 diabetes mellitus].

This study is to explore the genetic model of type 2 diabetes mellitus (type 2 DM) among the hereditary family. One hundred and thirty-six pedigrees of familial type 2 DM were studied. The heritability of type 2 DM was estimated according to Falconer's method and the multi-factorial inheritance analyzed according to Penrose's method. Complex segregation analysis was performed using S.A.G.E-REGD. The heritability of familial type 2 DM was 94 07%-/+5.84%. Dominant major gene might influence the genesis of type 2 DM. Analysis of multi-factorial inheritance indicated that there be two genetic patterns respectively in male and female populations. By complex segregation analysis,environment,non-transmitted and co-dominant inheritance were rejected. Autosomal dominant (AD) inheritance and autosomal recessive (AR) inheritance was accepted but AR inheritance was the best pattern. This study suggested that type 2 DM had significant heritability and genetic heterogeneity,which appeared to be a disease of multi-factorial inheritance generally and autosomal dominant (AD) inheritance in part of pedigrees.