Pulsed thermoreflectance imaging for thermophysical properties measurement of GaN epitaxial heterostructures.

Multilayer heterostructures composed of a substrate and an epitaxial film are widely utilized in advanced electronic devices. However, thermal bottlenecks constrain their performance and reliability, and efficient approaches to comprehensively measure the thermophysical properties of heterostructures are urgently needed. In this work, a pulsed thermoreflectance imaging (PTI) method is proposed, which combines the transient temperature mapping of thermoreflectance thermal imaging with transient pulsed excitation. By executing merely three transient tests, six thermophysical properties, including the film thermal conductivity and specific heat capacity, the substrate thermal conductivity and specific heat capacity, the film-substrate thermal boundary resistance, and the equivalent thermal conductivity of the insulating layer, can be simultaneously measured in a heterostructure sample. The proposed method applies a pulsed current excitation to a metal heater line on the sample surface and utilizes the thermoreflectance thermal imaging system to measure the temperature of different spatial regions on the sample surface at different time windows. The temporal and spatial variation information of the temperature field is then extracted and combined with finite element method inversion calculation to obtain the thermophysical properties of heterostructures. To validate the accuracy and reliability of this method, we conducted measurements on a GaN-on-SiC heterostructure sample and obtained thermophysical properties consistent with the representative literature data that have previously been reported. The proposed PTI method, characterized by its high sensitivity, demonstrates good efficiency and reliability in conducting comprehensive thermophysical property characterization of GaN epitaxial heterostructures.

Neuroprotective effect of Da Chuanxiong Formula against cognitive and motor deficits in a rat controlled cortical impact model of traumatic brain injury.

ETHNOPHARMACOLOGICAL RELEVANCE: Da Chuanxiong Formula (DCXF) is one of the famous herb pairs that contains dried rhizomes of Ligusticum chuanxiong Hort. and Gastrodia elata Bl. in the mass ratio of 4:1. This classic representative traditional Chinese medicine has been widely used to treat brain diseases like headache and migraine caused by blood stasis and wind pathogen. However, the therapeutic effect of DCXF on traumatic brain injury (TBI) has not been reported yet. AIM OF STUDY: The present study was performed to investigate the neuroprotective effects of DCXF and its underlying mechanisms in the controlled cortical impact (CCI)-induced TBI rat model. MATERIALS AND METHODS: Male Sprague-Dawley rats were divided into four groups: Sham, TBI control, 1X DCXF (520.6 mg/kg) and 5X DCXF (2603.0 mg/kg). Two treatment groups (1X and 5X DCXF) were intragastrically administered daily for 7 days before CCI-induced TBI and then DCXF treatments were continued post-TBI until the animal behavioral tests, including Morris water maze test, acceleration rotarod motor test and CatWalk quantitative gait analysis test, were done. The brain water content and blood brain barrier (BBB) integrity were measured by wet-dry weight method and Evans blue method, respectively. The number of neuron cells, neural stem cells (NSCs), GFAP positive cells (astrocyte) as well as Iba-1 positive cells (microglia) were determined by histology and immunohistochemistry. RESULTS: Treatment with DCXF significantly improved the learning ability and memory retention in Morris water maze test, and remarkably enhanced motor performances in acceleration rotarod motor test and catwalk quantitative gait analysis test after TBI. Moreover, DCXF treatment was able to reduce BBB permeability, brain edema, microglia and astrocyte activation, improve the proliferation of NSCs and decrease neurons loss in the brain with TBI. CONCLUSIONS: The present study demonstrated that DCXF treatment could decrease BBB leakage and brain edema, reduce neuron loss, microglia and astrocyte activation, and increase NSCs proliferation, which may contribute to the cognitive and motor protection of DCXF in the TBI rats. It is the first time to provide potentially underlying mechanisms of the neuroprotective effect of DCXF on TBI-induced brain damage and functional outcomes.

Phytochemistry and pharmacology of the genus Leonurus: The herb to benefit the mothers and more.

Plants belonging to the genus Leonurus, also named motherwort, are traditionally used for anti-gynecological disorder in East Asia, and for sedative in Europe. Chemical investigation of the genus Leonurus not only enriched the natural products library, but also enlarged the pharmacological application of this traditional herb. In this review, we systematically summarized the structures of 259 compounds isolated from the genus Leonurus, featured with 147 labdane diterpenoids. The reported bioactivity studies up to 2017 are presented in the second part, with the main focus on the isolated compounds and also concerning the extracts. In addition to the traditional uterine contraction and sedative activity, recently the cardiovascular protection effect of leonurine has drawn most attention. Other than that, neuroprotection, anti-inflammation, anti-cancer, anti-platelet aggregation and many other activities have been assigned to various compounds from the genus Leonurus. Among 70 bioactivity references cited in this review, 57% of them were concentrated on two alkaloids (leonurine and stachydrine), whereas only 20% are about the 147 diterpenoids. Anti-inflammation is the major bioactivity discovered so far for the labdane diterpenoids from the genus Leonurus, whose further therapeutic potential still remains for exploration.

Grading effect of abnormal glucose status on arterial stiffness and a new threshold of 2-h post-load glucose based on a Chinese community study.

AIMS/INTRODUCTION: To investigate the relationship between various glucose metabolic status and arterial stiffness, and further explore the threshold of blood glucose indices for the risk of arterial stiffness. MATERIALS AND METHODS: The present cross-sectional study included 4,851 individuals from a Chinese community. Overnight fasting blood glucose and 2-h post-load glucose were sampled. Arterial stiffness was measured as brachial-ankle pulse wave velocity. The association was examined using generalized linear regression models. The threshold effect was explored using two piecewise linear regression models by the smoothing plot. RESULTS: After adjustment for covariates, isolated impaired fasting glucose, isolated impaired glucose tolerance, combined glucose intolerance and newly diagnosed diabetes mellitus were associated with a greater risk of arterial stiffness compared with normal glucose tolerance (B = 18.09, 95% confidence interval [CI] 0.42-35.76, P = 0.045; B = 28.51, 95% CI: 3.40-53.62, P = 0.026; B = 60.70, 95% CI: 38.37-83.04, P < 0.001; B = 95.06, 95% CI: 71.88-118.25, P < 0.001, respectively). Furthermore, there was a non-linear relationship between 2-h post-load glucose and arterial stiffness. A threshold for 2-h post-load glucose of 6.14 mmol/L was observed for the risk of arterial stiffness. CONCLUSIONS: Impaired fasting glucose, impaired glucose tolerance, combined glucose intolerance and newly diagnosed diabetes mellitus were related to a greater risk of arterial stiffness compared with normal glucose levels. A threshold for 2-h post-load glucose of 6.14 mmol/L probably exists for the risk of arterial stiffness.

A traditional Chinese formula composed of Chuanxiong Rhizoma and Gastrodiae Rhizoma (Da Chuanxiong Formula) suppresses inflammatory response in LPS -induced RAW 264.7 cells through inhibition of NF-κB pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Da Chuanxiong Formula (DCXF) which origins from Jin Dynasty is a famous classical 2-herb Chinese medicinal prescription. It is composed of dried rhizomes of Ligusticum chuanxiong (Chuanxiong Rhizoma, CR) and Gastrodia elata (Gastrodiae Rhizoma, GR) at the ratio of 4:1 (w/w). It has been used to treat headache which is caused by wind pathogen and blood stasis for thousands of years in China. AIM OF STUDY: The present study was performed to investigate the anti-inflammatory effect of DCXF and elucidate its underlying molecular mechanisms using LPS-stimulated RAW 264.7 cells. MATERIALS AND METHODS: The anti-inflammatory effect of DCXF was evaluated using LPS-stimulated RAW 264.7 cells. Generation of nitric oxide (NO) and prostaglandin E2 (PGE2) were measured by the Griess colorimetric method and enzyme-linked immunosorbent assay (ELISA), respectively. The gene expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were detected by reverse transcription-polymerase chain reaction (RT-PCR). Furthermore, the effect of DCXF on NF-κB activation was measured by western blot assay. RESULTS: Treatment with DCXF significantly suppressed the productions of NO and PGE2 through inhibitions of iNOS and COX-2 expressions in LPS-stimulated RAW 264.7 cells. DCXF significantly decreased IκBα phosphorylation, inhibited p65 expression and reduced p-p65 level. These results suggested the anti-inflammatory effect of DCXF was associated with the reduction of inflammatory mediators through inhibition of NF-κB pathway. CONCLUSIONS: These results indicated that DCXF inhibited inflammation in LPS-stimulated RAW 264.7 cells through inactivation of NF-κB pathway.

Relationships between cell cycle pathway gene polymorphisms and risk of hepatocellular carcinoma.

AIM: To investigate the associiations between the polymorphisms of cell cycle pathway genes and the risk of hepatocellular carcinoma (HCC). METHODS: We enrolled 1127 cases newly diagnosed with HCC from the Tumor Hospital of Guangxi Medical University and 1200 non-tumor patients from the First Affiliated Hospital of Guangxi Medical University. General demographic characteristics, behavioral information, and hematological indices were collected by unified questionnaires. Genomic DNA was isolated from peripheral venous blood using Phenol-Chloroform. The genotyping was performed using the Sequenom MassARRAY iPLEX genotyping method. The association between genetic polymorphisms and risk of HCC was shown by P-value and the odd ratio (OR) with 95% confidence interval (CI) using the unconditional logistic regression after adjusting for age, sex, nationality, smoking, drinking, family history of HCC, and hepatitis B virus (HBV) infection. Moreover, stratified analysis was conducted on the basis of the status of HBV infection, smoking, and alcohol drinking. RESULTS: The HCC risk was lower in patients with the MCM4 rs2305952 CC (OR = 0.22, 95%CI: 0.08-0.63, P = 0.01) and with the CHEK1 rs515255 TC, TT, TC/TT (OR = 0.73, 95%CI: 0.56-0.96, P = 0.02; OR = 0.67, 95%CI: 0.46-0.97, P = 0.04; OR = 0.72, 95%CI: 0.56-0.92, P = 0.01, respectively). Conversely, the HCC risk was higher in patients with the KAT2B rs17006625 GG (OR = 1.64, 95%CI: 1.01-2.64, P = 0.04). In addition, the risk was markedly lower for those who were carriers of MCM4 rs2305952 CC and were also HBsAg-positive and non-drinking and non-smoking (P < 0.05, respectively) and for those who were carriers of CHEK1 rs515255 TC, TT, TC/TT and were also HBsAg-negative and non-drinking (P < 0.05, respectively). Moreover, the risk was higher for those who were carriers of KAT2B rs17006625 GG and were also HBsAg-negative (P < 0.05). CONCLUSION: Of 12 cell cycle pathway genes, MCM4, CHEK1 and KAT2B polymorphisms may be associated with the risk of HCC.

[Relationship between brachial-ankle pulse wave velocity and glycemic control of type 2 diabetes mellitus patients in Beijing community population].

OBJECTIVE: To explore the correlation between glycemic control of type 2 diabetes mellitus (T2DM) patients and brachial-ankle pulse velocity (baPWV). METHODS: A community-based cross-sectional study was conducted in Beijing, China. Every subject underwent physical examinations, glycated hemoglobin (HbA1c), blood lipid and baPWV measurements and completed a standardized questionnaire. T2DM patients were divided into well controlled and poorly controlled groups according to HbA1c levels. The correlation between glycemic control of T2DM patients and baPWV was analyzed. RESULTS: In this study, 1 341 subjects were recruited, including 733 T2DM patients and 608 non-diabetes subjects. Compared with non-diabetes subjects, abnormal baPWV (baPWV≥1 700 cm/s) rate for T2DM patients was higher (40.8% vs. 26.8%, P<0.001). With HbA1c<6.5% or <7.0% as the aim of glycemic control in T2DM patients, the abnormal baPWV rates for non-diabetes subjects, well controlled and poorly controlled T2DM patients were significantly different (non-diabetes vs. HbA1c<6.5% T2DM vs. HbA1c≥6.5% T2DM: 26.8% vs. 32.8% vs. 42.6%, P<0.001; non-diabetes vs. HbA1c<7.0% T2DM vs. HbA1c≥7.0% T2DM: 26.8% vs. 36.1% vs. 43.4%, P<0.001). After being adjusted for gender, age, smoking status, diabetes mellitus family history, T2DM duration, cardiovascular diseases (CVD), waist hip ratio (WHR), systolic blood pressure (SBP), diastolic blood pressure (DBP), total triglycerides (TG), high density lipoprotein cholesterol (HDL-C), and low density lipoprotein cholesterol (LDL-C), the Logistic regression models suggested that glycemic control status of T2DM patients was associated with abnormal baPWV. Compared with non-diabetes subjects, the ORs for abnormal baPWV in HbA1c<6.5% T2DM patients and HbA1c≥6.5% T2DM patients were 0.927(95%CI 0.560-1.537) and 1.826 (95%CI 1.287-2.591). Compared with non-diabetes subjects, the ORs for abnormal baPWV in HbA1c<7.0% T2DM patients and HbA1c≥7.0% T2DM patients were 1.210 (95%CI 0.808-1.811) and 1.898 (95%CI 1.313-2.745). CONCLUSION: The glycemic control status of T2DM patients from communities is significantly associated with baPWV. Poor glycemic control is a risk factor for abnormal baPWV. Keeping HbA1c under control might lower the risk of cardiovascular diseases in T2DM patients.

Interaction of type 2 diabetes mellitus with chromosome 9p21 rs10757274 polymorphism on the risk of myocardial infarction: a case-control study in Chinese population.

BACKGROUND: Myocardial infarction (MI) is a serious complication of Coronary Artery Disease (CAD). Previous studies have identified genetic variants on chromosome 9p21 and 6p24 that are associated with CAD, but further studies need to be conducted to investigate whether these genetic variants are associated with the pathogenesis of MI. We therefore performed this study to assess the association between the risk of MI and SNP rs10757274 on chromosome 9p21 and SNP rs6903956 on chromosome 6p24, and to explore the gene-environment interactions in a Chinese population. METHODS: A hospital-based case-control study, consisting of 502 MI patients and 308 controls, was conducted in a Chinese population. Demographic, behavioral information and clinical characteristics were collected, and genotyping of the two SNPs was performed using single base primer extension genotyping technology. The unconditional logistic regression (ULR) method was adopted to assess the association of the two SNPs with MI risk. Both generalized multifactor dimensionality reduction (GMDR) and ULR methods were applied to explore the effect of gene-environment interactions on the risk of MI. RESULTS: After adjusting for covariates, it was observed that SNP rs10757274 on chromosome 9p21 was significantly associated with MI. Compared with subjects carrying the AA genotype, subjects carrying the GA or GG genotypes had a higher MI risk (ORa = 1.52, 95% CI:1.06-2.19, pa = 0.0227; ORa = 2.40, 95% CI:1.51-3.81, pa = 0.0002, respectively). Furthermore, a two-factor gene-environment interaction model of CDKN2A/B (rs10757274) and type 2 diabetes mellitus (T2DM) was identified to be the best model by GMDR (p = 0.0107), with a maximum prediction accuracy of 59.18%, and a maximum Cross-validation Consistency of 10/10. By using the ULR method, additive interaction analysis found that the combined effect resulted in T2DM-positive subjects with genotype GG/GA having an MI risk 4.38 times that of T2DM-negative subjects with genotype AA (ORadd = 4.38, 95% CI:2.56-7.47, padd < 0.0001). CONCLUSIONS: These results show that gene polymorphism of CDKN2A/B (rs10757274) is associated with MI risk in a Chinese population. Furthermore, T2DM is likely to have an interaction with CDKN2A/B (rs10757274) that contributes to the risk of MI.

Solution-gated graphene field effect transistors integrated in microfluidic systems and used for flow velocity detection.

Solution-gated graphene field effect transistors (SGGT) were integrated in microfluidic systems. The transfer characteristics of a SGGT with an Ag/AgCl gate electrode shifted horizontally with the change of the ionic concentration of KCl solution in the microchannel and the relationship can be fitted with the Nernst equation, which was attributed to the change of the potential drop at the Ag/AgCl electrode. Therefore the gate electrode is one important factor for the ion sensitive property of the SGGT. Then SGGTs were used as flow velocity sensors, which were based on measuring the streaming potentials in microfluidic channels. A linear relationship between the shift of the transfer curve of the SGGT and the flow velocity was obtained, indicating that the SGGT is a promising transducer for measuring flow velocity in a microchip. Since the streaming potential is influenced by the three physical quantities, including the flow velocity, the ionic strength of the fluid and the zeta potential of the substrate, the device can be used for sensing any one of the three quantities when the other two were known. It is noteworthy that SGGTs have been used for various types of chemical and biological sensors. Array of the devices integrated in multichannel microchips are expected to find many important applications in the lab-on-a-chip systems in the future.