Fiber-tip Fabry-Pérot interferometer with a graphene-Au-Pd cantilever for trace hydrogen sensing.

The widespread utilization of hydrogen energy has increased the demand for trace hydrogen detection. In this work, we propose a fiber-optic hydrogen sensor based on a Fabry-Pérot Interferometer (FPI) consisting of a fiber-tip graphene-Au-Pd submicron film cantilever. The palladium (Pd) film on the cantilever surface is used as hydrogen-sensitive material to obtain high sensing sensitivity. Hydrogen sensing is realized by monitoring the resonant frequency shift of the FPI introduced by the interaction between Pd film and hydrogen molecules. The hydrogen sensor is proven for low-hydrogen-concentration detection with hydrogen concentrations in the range of 0-1000 ppm, and experimentally characterized by a highest sensitivity of 30.3 pm ppm-1 in a low hydrogen concentration of 0-100 ppm, which is more than two orders higher than for previously reported FPI-based sensors. In real-time hydrogen monitoring, a rapid reaction time of 31.5 s was achieved. This work provides a compact all-optical solution for the safe detection of low hydrogen concentrations, which is an interesting alternative for trace hydrogen detection in the aerospace industry, energy production, and medical applications.

Fiber optic hydrogen sensor based on a Fabry-Perot interferometer with a fiber Bragg grating and a nanofilm.

Hydrogen is widely used in industrial production and clinical medicine, and as fuel. Hydrogen becomes explosive when the hydrogen-air mixture ranges from 4 to 76 vol%; thus, a rapid hydrogen concentration measurement is particularly important in practical applications. We present a novel fiber optic hydrogen sensor with fast response fabricated from a graphene-Au-Pd sandwich nanofilm and an ultrashort fiber Bragg grating. The response time is only 4.3 s at a 3.5 vol% hydrogen concentration. When the measured hydrogen concentration was increased from 0 to 4.5 vol%, the optical resonance dip in the sensor near 1550 nm shifted by 290 pm. In addition, the sensor has an insertion loss of only -2.22 dB, a spectral contrast of 10.8 dB, and a spectral finesse of 5. Such a flexible, fast-response sensor is expected to be used in the development of hydrogen sensors with low power consumption.

Topical therapy with rhubarb navel plasters in patients with chronic constipation: Results from a prospective randomized multicenter study.

ETHNOPHARMACOLOGICAL RELEVANCE: Constipation is a functional gastrointestinal disorder and one of the most prevalent conditions encountered in primary care settings. Rhubarb navel dressings have been used for more than 2,000 years in Chinese medicine to treat constipation. However, the effect of topical rhubarb administration has still not been well recognized and this strategy is not yet established as an evidence-based approach. AIM OF THE STUDY: In this study, we performed a prospective multicentric randomized controlled trial to evaluate the efficacy and safety of rhubarb navel plasters for patients with chronic constipation. MATERIALS AND METHODS: A total of 374 patients from six teaching hospitals were prospectively included between 09/2016 and 10/2017 in the study based on Rome III criteria. All participants were randomly assigned (1:1) into verum/placebo group and given either Rheum officinale rhubarb powder or a placebo flour stick on the navel for 6 h/day/8 days. Primary outcome measures were the Cleveland Constipation Score (CCS) for the feces condition and Bristol Stool Scale (BSS) for stool consistency and 24 h defecation frequency. RESULTS: The groups demonstrated no statistical differences in demographic data, clinical diagnoses and concomitant medication at baseline. In patients treated with the verum CCS was 5.61 (day 8, 95% CI 5.15-6.07) compared to 8.62 (95% CI 8.07-9.18) in placebo-treated controls (P < 0.001). The mean change of CCS at the end of treatment (day 8 versus [vs] day 0) was 6.04 in verum-treated vs 2.73 in placebo-treated controls (P < 0.001). Also 24 h defecation frequency (BSS) showed superior results (day 5: 0.84 vs 0.62, 95% CI 0.67-0.80, P < 0.001; day 6: 0.82 vs 0.60, 95% CI 0.64-0.78, P < 0.01 and day 8: 0.82 vs 0.60, 95% CI 0.64-0.78, P < 0.01) and better BSS type classification during treatment than controls (P < 0.05). No significant differences in adverse events between both groups became obvious. CONCLUSION: Rhubarb navel plaster administration over an 8-day-treatment period resulted in significantly improved bowel function as demonstrated by the CCS, 24 h defecating frequency and BSS. Our results suggest that rhubarb navel plasters represent a feasible, safe and efficient application route for the treatment of patients suffering from chronic constipation.

A High-Strength Strain Sensor Based on a Reshaped Micro-Air-Cavity.

We demonstrate a high-strength strain sensor based on a micro-air-cavity reshaped through repeating arc discharge. The strain sensor has a micro-scale cavity, approximate plane reflection, and large wall thickness, contributing to a broad free spectrum range ~36 nm at 1555 nm, high fringe contrast ~38 dB, and super-high mechanical robustness, respectively. A sensitivity of ~2.39 pm/µÎµ and a large measurement range of 0 to 9800 µÎµ are achieved for this strain sensor. The strain sensor has a high strength, e.g., the tensile strain applied the sensor is up to 10,000 µÎµ until the tested the single-mode fiber is broken into two sections. In addition, it exhibited low thermal sensitivity of less than 1.0 pm/°C reducing the cross-sensitivity between tensile strain and temperature.

TNF-alpha promoter region polymorphisms affect HBV virus clearance in southern Chinese.

BACKGROUND: There are many cytokines, including TNF-α, TGFß, PGF, and other factors contributing towards fibrogenesis, that play a role in the control of HBV infection. Among these, TNF-α is the most important cytokine in host immune response to viral infection. This study aimed to determine whether differences in the promoter region of the TNF-α gene may alter the outcomes of HBV infection. METHODS: Two polymorphisms of tumor necrosis factor-α (TNF-α) gene, -308 G/A (rs1800629) and -863 C/A (rs1800630), were analyzed by DNA sequence in the case-control sample using 171 chronic HBV-infected patients and 227 recovered HBV-infected controls. All subjects were unrelated southern Han Chinese. RESULTS: For TNF-α-308, healthy controls compared to HBV infection have a significantly higher allele A and GA genotype frequency. For TNF-α-863, no significant differences in allele or genotype frequencies between the case groups and the control group were observed. CONCLUSIONS: This study provides evidence of a positive association between HBV clearance and TNF-α-308A.