Theoretical and experimental studies on channel impulse response of short-range non-line-of-sight ultraviolet communications.

A theoretical channel impulse response (CIR) model of short-range non-line-of-sight (NLOS) ultraviolet communications (UVC) in noncoplanar geometry under the single-scatter condition is proposed. Simulation results obtained from the widely accepted Monte-Carlo (MC)-based channel model of NLOS UVC are provided to verify corresponding theoretical results obtained from the proposed theoretical single-scatter CIR model. Additionally, an outdoor experiment with a light-emitting diode (LED) as the light source is first designed to measure the channel step response of NLOS UVC and to further validate the proposed theoretical single-scatter CIR model. By varying the different parameters of the transmitter and the receiver, such as the baseline range, the inclination angle, the azimuth angle, the beam divergence angle, and the field-of-view angle, the results of the proposed theoretical single-scatter CIR model and the MC-based channel model are exhibited and further analyzed in detail. Results indicate that the computational time cost by the proposed theoretical single-scatter CIR model is decreased to less than 0.6% of the MC-based one with comparable accuracy in assessing the temporal characteristics of NLOS UVC channels. Additionally, theoretical results obtained from the proposed theoretical single-scatter CIR model manifest satisfactory agreement with corresponding experimental measurements.

Parental smoking exposure before and during pregnancy and offspring attention-deficit/hyperactivity disorder risk: A Chinese child and adolescent cohort study.

Background: Previous studies revealed that maternal smoking exposure during pregnancy was an essential risk factor for offspring developing attention-deficit/hyperactivity disorder (ADHD). The impact of paternal smoking exposure 1 year before pregnancy on offspring ADHD risk is still unclear. Methods: The present study included 2,477 school-age children and their parents from the Shanghai Child and Adolescent Health Cohort who had complete data for offspring ADHD diagnosis and parents' smoking exposure before and during pregnancy information. A multivariate logistic regression model and Firth's logistic regression model were used to determine the associations of paternal smoking and parental smoke exposure patterns before and during pregnancy with offspring ADHD risk. Results: Children whose fathers smoked before pregnancy had a higher risk of developing ADHD [odds ratio (OR) = 2.59, 95% confidence interval (CI): 1.35-4.98] compared to those whose fathers had never been exposed to smoking. Similarly, parents who were exposed to smoking or second-hand smoke before pregnancy had 1.96 times (OR = 1.96, 95% CI: 1.19-3.22) more likely to have offspring with ADHD. Moreover, children whose parents were exposed to smoking both before and during pregnancy were 2.01 times (OR = 2.01, 95% CI: 1.29-3.12) more likely to develop ADHD. Conclusion: Paternal smoking before pregnancy and parental smoking exposure 1 year ahead of and throughout pregnancy were all risk factors for offspring developing ADHD.

Single-collision-induced path loss model of reflection-assisted non-line-of-sight ultraviolet communications.

By considering both scattering and reflection events as collision-induced events (CIEs), an analytical path loss model of reflection-assisted non-line-of-sight (NLOS) ultraviolet communications (UVC) is proposed with single CIE incorporated, which refers to the single-collision-induced (SCI) path loss model. More specifically, the analytical expressions of the received optical energy resulting from single-scatter and single-reflection events in reflection-assisted NLOS UVC are respectively derived. Then, in terms of those two expressions, the expression of the proposed SCI path loss model is obtained. Finally, Monte-Carlo (MC) simulations and experimental results are given to verify the correctness and effectiveness of the proposed SCI path loss model. The results manifest that the proposed SCI path loss model can work well in both coplanar and noncoplanar geometry of the reflection-assisted NLOS UVC.

Modeling of ultraviolet propagation from air to human epidermis with wavelength range of 200-300 nm.

Ultraviolet (UV) technology plays an important role in the fields of sterilization, disinfection, and short-range wireless optical communications. In this Letter, a theoretical model to determine the UV radiation intensity (UVRI) on human skin is put forward based on the Monte Carlo method, where the UV wavelength ranges from 200 to 300 nm. Meanwhile, the UVRI evaluation algorithm is provided to reproduce the simulation results. Furthermore, the penetration depth of UV radiation in the human epidermis is investigated, which can be used to assess whether UV radiation causes damage to human health. Simulation results coincide with the existing experimental results that the 222-nm UV radiation is harmless to humans at the given dose of 1.7 mJ/cm2. This work provides theoretical guidelines for the power control of a UV system when humans are in the vicinity.

Single-scatter path loss model of LED-based non-line-of-sight ultraviolet communications: publisher's note.

This publisher's note contains corrections to Opt. Lett.46, 4013 (2021)OPLEDP0146-959210.1364/OL.435418.

Modeling of UV diffused-LOS communication channel incorporating obstacle and its applicability analysis.

Existing studies of the ultraviolet (UV) channel mainly focus on non-line-of-sight (NLOS) scenarios, while line-of-sight (LOS) scenarios are generally neglected since obstacles sometimes block them. To fill this gap, a UV diffused-LOS channel model in the presence of an obstacle is proposed for the first time, to the best of our knowledge. For easy interpretation, the whole derivation is combined with four typical positions of the obstacle. Moreover, the applicability of the proposed model is investigated via comparison with the classical Monte Carlo simulation model, where the transceiver elevation angle and azimuth angle are always kept optimal. Calculation and simulation results show that when the obstacle thickness is relatively small, the channel attenuation of the UV diffused-LOS system is lower than that of the UV NLOS system with the variation of obstacle width, height, and distance between transceiver and obstacle. In addition, an expression of the impulse response time of the diffused-LOS channel with the obstacle is also derived for tractable analysis.

Single-scatter path loss model of LED-based non-line-of-sight ultraviolet communications.

Light-emitting diodes (LEDs) are popularly used as light sources in non-line-of-sight (NLOS) ultraviolet communications (UVC). However, currently reported single-scatter path loss (PL) models of NLOS UVC links assume that the radiant intensity of the light source is uniformly distributed within the beam divergence angle, which cannot well characterize the light emission pattern of LEDs. In this Letter, we propose a single-scatter PL model for LED-based NLOS UVC systems, and the corresponding analytical expression is derived by modeling the LED emission pattern as a Lambertian distribution. Monte Carlo simulations and experimental results are provided to verify the effectiveness of the proposed PL model. Results show that the proposed model can accurately predict PL results in actual situations. The root-mean-square error of the proposed PL model is only about 1 dB in typical scenarios with experimental results as benchmarks. Also, the proposed model is much easier to implement than the currently reported PL model with the light source model of a uniformly distributed emission pattern.

Gender-specific association between non-alcoholic fatty liver disease and type 2 diabetes mellitus among a middle-aged and elderly Chinese population: An observational study.

ABSTRACT: Limited data are available regarding the association of non-alcoholic fatty liver disease (NAFLD) with the risk of type 2 diabetes mellitus (T2DM) in China. Therefore, the purpose of this study is to evaluate the gender-specific association between NAFLD and T2DM risk in a middle-aged and elderly Chinese population.This cross-sectional study was carried out in a group of 1492 Chinese adults (60.30% males) aged between 45 and 69 years old, in Hangzhou city, Zhejiang province who were attending their annual health check-up from June 2015 to December 2016 in the Medical Center for Physical Examination, Zhejiang Hospital. Face-to-face interviews were conducted using a written questionnaire. NAFLD was divided into none, mild, moderate/severe based on ultrasound examination. Logistic regression analyses were employed to determine the relationship between NAFLD and the risk of T2DM, with adjustment of potential confounding variables.Of the 1492 participants, 163 (10.92%) were diagnosed with T2DM. Educational level, smoking, body mass index (BMI), waist circumference (WC), waist-hip ratio (WHR), systolic blood pressure (SBP), diastolic blood pressure (DBP), fasting glucose (FG), triglycerides (TG), alanine aminotransferase (ALT), asparagine aminotransferase (AST)and the prevalence of T2DM were significantly higher in males than in females (P < .05). Besides, females had significantly higher levels of high density lipoprotein-cholesterol (HDL-C) (1.51 ±â€Š0.37 vs 1.29 ±â€Š0.42, P < .001) than males. Pearson bivariate correlation analysis indicated that FG was positively associated with weight, BMI, WC, WHR, SBP, DBP, TG, TC, ALT and AST in both males and females (P < .05). Besides, FG was inversely associated with HDL-C in females (P < .001). After adjusting for confounding variables, NAFLD was positively associated with the risk of T2DM, and the effect of NAFLD on T2DM was stronger in males (OR = 2.442, 95%CI: 1.003-3.757) than in females (OR = 1.814, 95%CI: 1.011-3.257).Our data showed that NAFLD was significantly associated with the risk of T2DM in middle-aged and elderly males than in females. Further prospective cohort studies are needed to determine the causal effect of NAFLD on T2DM.

Modeling of ultraviolet omni-directional multiple scattering channel based on Monte Carlo method.

Existing studies of ultraviolet (UV) communication channel models focus mainly on point-to-point scenarios. To analyze UV channel characteristics in omni-directional scenarios, we propose a multiple scattering omni-directional channel model based on the Monte Carlo method in this Letter, where we assume that the receiver can be anywhere in a certain area and all the receivers point to the vertical axis of the transmitter. Meanwhile, we validate the proposed model in comparison to the existing point-to-point Monte Carlo simulation model. Simulation results demonstrate that a single scattering model is not applicable to omni-directional analysis due to the difference in path loss between the single scattering model and the multiple scattering model. Furthermore, the transceiver configurations can affect the coverage area of the UV omni-directional communication system significantly. This work presents a new way to obtain UV path loss distribution and provides guidelines for the omni-directional communication system design.

Dietary exposure of lead in primary, middle and high school students in Pudong new area of Shanghai / 中国学校卫生

Objective@#To obtain the dietary exposure of lead in primary, middle and high school students, and to provide basic foundation for food safety risk assessment and management for children and adolecsents.@*Methods@#Weighing method, 3-days hour dietary survey, combining with the food frequency questionnaire, was applied to obtain basic dietary data in 616 primary, middle and high school students selected through multi-stage randdom sampling method from Pudong new area of shanghai. Data on lead concentrations were derived from the food safety risk monitoring system, which included 1 145 samples.@*Results@#Lead was detected in 568 of 1 145 samples (49.61%) from 10 categories of foods. The exceeding standard rate was 3.58% (41 samples exceeded). The average content of lead was (0.12±0.25) mg/kg, fungi and algae, beans and the aquatic products were found to be the primary food sources of lead exposure. The average dietary lead exposure in primary, middle and high school students was 9.94 μg/kg per week, accounted for 39.76% of PTWI. The lead exposure level at the 97.5th percentile which accounted for 118.24% of PTWI was 29.56 μg/kg. Vegetables, beans and cereal foods were the mainly source of dietary lead exposure, with average dietary lead exposure 2.57, 2.44 and 1.43 μg/kg peer week, accounted for 10.26%, 9.76% and 5.74% of PTWI, respectively.@*Conclusion@#Lead is present in some foods available in local markets in Pudong New Area, Shanghai. Low level of dietary exposure to lead is found in primary, middle and high school students, however, it depends on dietary pattern. Continued efforts are needed to reduce the dietary exposure of lead in school students.

Modeling of ultraviolet scattering propagation and its applicability analysis: erratum.

This erratum provides corrections to Fig. 1, Eqs. (1b) and (6b), and Case (e) of Opt. Lett.44, 4953 (2019)OPLEDP0146-959210.1364/OL.44.004953.

Modeling of ultraviolet scattering propagation and its applicability analysis.

The existing ultraviolet (UV) single scattering models do not incorporate the applicability of transceiver geometry, which makes them have certain errors even in short-range cases. To solve this issue, we propose a single scattering model in this Letter, which is suitable for the case where the transceiver field of view is above ground. This meets the requirements of general UV communication. For tractable analysis, we utilize the number of intersections between special rays on a transceiver cone to classify communication scenarios. Calculation results show that when the transceiver elevation angle exceeds certain values, the path loss difference between the single scattering model and Monte Carlo simulation model increases rapidly, which implies that single scattering approximation is not applicable to these conditions even in short-range cases. This work presents a new way to obtain the path loss of the UV channel and provides guidelines for experimental system design.

Reduced interleukin-38 in non-small cell lung cancer is associated with tumour progression.

Lung cancer continues to be the leading cause of cancer-related deaths worldwide due to its high incidence, malignant behaviour and lack of major advancements in treatment strategy. The occurrence and development of lung cancer is closely related to inflammation. Thus, we conducted the present study to investigate the effects of IL-38 (interleukin-38), a newly identified anti-inflammatory factor, on non-small cell lung cancer (NSCLC), which accounts for about 85% of all lung cancers. We first evaluated the IL-38 expression in 384 pairs of NSCLC samples and their adjacent normal mucosa by real-time PCR, ELISA (enzyme-linked immunoassay) and tissue microarrays. Then the role of IL-38 on patient survival rates, cancer progression and their sensitivity to chemotherapy drugs was assessed. IL-38 was barely expressed in the NSCLC tissues but highly expressed in the adjacent normal tissues. The downregulation of IL-38 was significantly correlated with the results of the American Joint Committee on Cancer stage and degree of differentiation, and it was also shown to be an independent prognostic indicator of disease-free survival and overall survival for patients with NSCLC. Overexpression of IL-38 in NSCLC cells suppressed cell migration, invasion, proliferation and colony formation through suppressing ß-catenin. IL-38 inhibited NSCLC formation in a mice model and sensitized the cancer cells to chemotherapy drugs. Our results show that IL-38 plays an inhibitory role in NSCLC development and functions as a novel prognostic indicator and a potential therapeutic target.

Plasma Homocysteine and Serum Folate and Vitamin B12 Levels in Mild Cognitive Impairment and Alzheimer's Disease: A Case-Control Study.

Homocysteine (Hcy) is a risk factor for brain atrophy, cognitive impairment, and dementia. Vitamin B12 and folate are cofactors necessary for the methylation of Hcy. However, there is some debate regarding the differing levels of plasma Hcy and serum folate and vitamin B12 among healthy controls, patients with mild cognitive impairment (MCI), and patients with Alzheimer's disease (AD). This study aimed to evaluate how the levels of plasma Hcy and its biological determinants, folate and vitamin B12, are related to MCI and AD in older Chinese adults. This is a case-control study including 112 subjects with MCI, 89 AD patients and 115 healthy controls. Diagnosis of AD was made according to the NINCDS-ADRDA and MCI with modified Petersen's criteria. Serum folate and vitamin B12 concentrations were analyzed by radioimmunoassay, and plasma Hcy was assessed by a high-performance liquid chromatography-fluorescence method. Multivariate analysis of regression was used to examine the odds ratio (OR) of MCI or AD with Hcy or vitamin levels. Results have shown that serum folate and vitamin B12 levels were significantly lower, but the plasma Hcy level was higher, in patients with MCI and AD than in healthy controls. Multivariate regression analyses showed that subjects in the lowest folate tertile had significantly higher adjusted ORs for MCI (OR: 3.07; 95% confidence interval [CI]: 1.12, 8.07) and AD (3.42; 95% CI: 1.15, 8.34) compared to subjects in the highest tertile. The highest Hcy tertile was significantly associated with MCI (adjusted OR: 2.81; 95% CI: 1.15, 4.73) and AD (adjusted OR: 3.64; 95% CI: 1.13, 9.04) compared to the lowest tertile. No association existed between low vitamin B12 levels and AD or MCI (p > 0.05). Low blood levels of folate and vitamin B12 and elevated Hcy levels were associated with MCI and AD in older Chinese adults, and the association was stronger for AD.

Allicin inhibits tubular epithelial-myofibroblast transdifferentiation under high glucose conditions in vitro.

Previous studies have suggested that tubular epithelial-mesenchymal transition (EMT) is an important event in renal tubulointerstitial fibrosis, which is a clinical characteristic of diabetic nephropathy. The present study aimed to investigate the effect of allicin, the major biological active component of garlic, on the EMT of a human renal proximal tubular epithelial cell line (HK-2) cultured under high glucose concentrations. HK-2 cells were exposed for 48 h to 5.5 or 25 mmol/l D-glucose, 25 mmol/l D-glucose plus allicin (2.5, 5, 10 or 20 µg/ml) or 25 mmol/l D-glucose plus 20 µmol/l PD98059, a selective inhibitor of the mitogen activated protein kinase/extracellular signal-regulated kinase (ERK) signaling pathway. The EMT of HK-2 cells was assessed by analyzing the protein expression of E-cadherin, α-smooth muscle actin (α-SMA), vimentin and collagen I via immunocytochemistry. In addition, reverse transcription-quantitative polymerase chain reaction and western blotting were used to detect the expression levels of transforming growth factor (TGF)-ß1 and phosphorylated (p)-ERK1/2. Marked morphological changes were observed in HK-2 cells cultured under high glucose conditions, and these changes were abrogated by simultaneous incubation with allicin and PD98059. The expression levels of α-SMA, vimentin and collagen I were significantly increased in HK-2 cells cultured under high glucose conditions, as compared with those cultured under normal glucose conditions (P<0.01). Conversely, the expression levels of E-cadherin were significantly decreased upon stimulation with high glucose (P<0.01). Furthermore, the expression levels of TGF-ß1 and p-ERK1/2 were significantly upregulated in HK-2 cells cultured under high glucose conditions, as compared with those cultured under normal glucose conditions (P<0.05). Allicin partially reversed the high-glucose-induced increase in α-SMA, vimentin and collagen I expression (P<0.01 at 20 µg/ml), increased the expression of E-cadherin, and significantly downregulated the high glucose-induced expression of TGF-ß1 and p-ERK1/2 in a dose-dependent manner (P<0.05). The results of the present study suggested that high glucose concentrations induced the EMT of HK-2 cells, and that allicin was able to inhibit the EMT, potentially via regulation of the ERK1/2-TGF-ß1 signaling pathway.

Protective effects of allicin on streptozotocin-induced diabetic nephropathy in rats.

BACKGROUND: Studies in animal models have shown that allicin, a major biologically active component of garlic, can play a role in the prevention of tissue fibrosis in the liver, lung and heart, mainly related to the inhibition of fibroblast proliferation, fibrogenic cytokine secretion and extracellular matrix synthesis. This study aimed to investigate the protective effects of allicin on renal damage in streptozotocin (STZ)-induced diabetic rats. STZ-induced diabetic rats were administered allicin (15, 30 and 45 mg · kg-1 · day-1 ) via daily intra-gastric gavage for 12 weeks. The levels of fasting blood glucose (FBG), blood urea nitrogen (BUN), serum creatinine (sCr), lipid and 24 h urine albumin excretion (UAE) were measured at the end of weeks 4, 8 and 12. The renal histopathology and the expression levels of collagen I, transforming growth factor ß1 (TGF-ß1) and phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK1/2) were measured using immunohistochemistry and/or western blotting. RESULTS: In 12 week STZ-induced diabetic rats, severe hyperglycemia and albuminuria were markedly developed. Treatment with allicin for 12 weeks ameliorated diabetes-induced morphological alterations of the kidney and decreased FBG, BUN, sCr, triglyceride (TG) and 24 h UAE in diabetic rats. The expression levels of collagen I, TGF-ß1 and p-ERK1/2 were significantly decreased by allicin treatment. CONCLUSION: These results suggested that allicin may play a protective role in diabetic nephropathy via the TGF-ß1/ERK pathway in diabetic rats. © 2016 Society of Chemical Industry.

Effects of DHA Supplementation on Hippocampal Volume and Cognitive Function in Older Adults with Mild Cognitive Impairment: A 12-Month Randomized, Double-Blind, Placebo-Controlled Trial.

Docosahexaenoic acid (DHA) is important for brain function, and higher DHA intake is inversely correlated with relative risk of Alzheimer's disease. The potential benefits of DHA supplementation in people with mild cognitive impairment (MCI) have not been fully examined. Our study aimed to determine the effect of DHA supplementation on cognitive function and hippocampal atrophy in elderly subjects with MCI. This was a randomized, double-blind, placebo-controlled trial in Tianjin, China. 240 individuals with MCI aged 65 years and over were recruited and equalized randomly allocated to the DHA or the placebo group. Participants received 12-month DHA supplementation (2 g/day) or corn oil as placebo. Both global and specific subdomains of cognitive function and hippocampal volume were measured at baseline, 6 months, and 12 months. Both changes were analyzed by repeated-measure analysis of variance (ANOVA). This trial has been registered: ChiCTR-IOR-15006058. A total of 219 participants (DHA: 110, Placebo: 109) completed the trial. The change in mean serum DHA levels was greater in the intervention group (+3.85%) compared to the control group (+1.06%). Repeated-measures analyses of covariance showed that, over 12 months, there was a significant difference in the Full-Scale Intelligence Quotient (ηp2 = 0.084; p = 0.039), Information (ηp2 = 0.439; p = 0.000), and Digit Span (ηp2 = 0.375; p = 0.000) between DHA-treated versus the placebo group. In addition, there were significant differences in volumes of left hippocampus (ηp2 = 0.121, p = 0.016), right hippocampus (ηp2 = 0.757, p = 0.008), total hippocampus (ηp2 = 0.124, p = 0.023), and global cerebrum (ηp2 = 0.145, p = 0.032) between the two groups. These findings suggest that DHA supplementation (2 g/day) for 12 months in MCI subjects can significantly improve cognitive function and slow the progression of hippocampal atrophy. Larger, longer-term confirmatory studies are warranted.