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Electrochemical sensors embedded in hydrogelbased contact lenses provide valuable health-related information, enabling non-invasive and real-time continuous monitoring. Recently, considerable progress has been made in tear based electrochemical sensors. The scope of reported analytes is continuously expanding. This review identifies key chemical biomarkers (including metabolites, ions, proteins) that can be electrochemically detected in tears. The working principles of i) amperometric enzymatic biosensors, ii) ion-selective sensors for pH and ions, iii) voltammetric sensors and iv) affinity sensors are summarized. This review provides guidelines for the future development of contact lens based electrochemical sensors. [ABSTRACT FROM AUTHOR]

This report describes an efficient nitrating system for the nitration of arenes at room temperature by using an equivalent of nitric acid in HFIP (1,1,1,3,3,3-hexafluoroisopropanol). The π-complex intermediate of an arene with a nitronium ion stabilized by HFIP can be directly observed by UV–vis spectra and is supported by theoretical calculations. [ABSTRACT FROM AUTHOR]

An ultrasonic sensor based on extrinsic Fabry–Pérot interference (EFPI) has been designed and demonstrated to detect the ultrasonic wave signal. The sensitivity and natural frequency of fiber Fabry–Pérot (F-P) sensor with different structure parameter have been simulated by COMSOL. The simulation results illustrate that the sensitivity is up to 1.737 nm/kPa and the natural frequency is 2.1 MHz, when the silica diaphragm thickness is 2 μm, the radius is 90 μm, and the cavity length is 18 μm. The most suitable parameters have been selected and the F-P sensor has been fabricated. When the ultrasonic signals with the frequencies of 40 kHz and 1.2 MHz are respectively applied to the sensor, the frequencies detected by the EFPI ultrasonic sensor are 39 kHz and 1.21 MHz based on a partial discharge detection experiment for the designed demodulation system. The experimental results show that the sensor can accurately detect ultrasonic signals. As an excellent platform for ultrasonic signal sensing, this EFPI ultrasonic sensing system has great potential applications in partial discharge detection field. [ABSTRACT FROM AUTHOR]

3-Substituted 2,5-dimethylpyrazines were synthesized in high yields via a one-pot cascade annulation of easily available propargyl amine with aldehydes catalyzed by Au(PPh2Cy)Cl. [ABSTRACT FROM AUTHOR]

An efficient coupling reaction of epoxides with CO2 affording cyclic carbonates with the use of 2,2',2''-terpyridine as catalyst under solvent-free conditions has been developed. [ABSTRACT FROM AUTHOR]

Background: Abelmoschus esculentus L. belonging to the family Malvaceae is a kind of one year herbage plant, which is one of the most important vegetables widely grown in Nigeria for its tender fruits and young leaves. It's easy to be cultivated and grows well in both tropical and temperate zones, that is, it is widely planted from Africa to Asia, South European to America. A new flavonol glycoside characterized as 5,7,3',4'-tetrahydroxy-4"-O-methyl flavonol -3-O-β-Dglucopyranoside (1) has been isolated from the fruit of A. esculentus together with one known compound 5,7,3',4'-tetrahydroxy fl avonol -3-O-[β-D-glucopyranosyl-(1→6)]-β-D-glucopyranoside (2). The structure of the new compound was elucidated on the basis of its spectral data, including 2-D NMR and mass (MS) spectra. The antioxidant activities of the isolated compounds 1 and 2 were evaluated by 2 assays, the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and ferric reducing antioxidant power (FRAP). The present work deals with the isolation, identification and antioxidant activity of the two compounds. Materials and Methods: The compounds were isolated by Diaion HP-20, Sephedex LH-20 column chromatography methods, their structures were identified by physicochemical properties and spectroscopic analysis. The antioxidant activities of the isolated compounds 1 and 2 were evaluated by two assays, e.g., DPPH and FRAP. Results: Two fl avonol glycosides have been isolated from the fruit of Abelmoschus esculentus L. for the first time, and the compound 1 was a new compound, the compound 2 was isolated from the plant for the first time. Conclusion: The results show that the two fl avonol glycosides have strong ability for scavenging DPPH and FRAP free radical by the experiment of antioxidant activities, so A. esculentus may be a natural antioxidants resource. [ABSTRACT FROM AUTHOR]

This paper investigates the dynamics of a two-stage supply chain consisting of one retailer and one distributor with order-up-to control policy. A discrete time state space model is developed to analyze the system. Due to the constraints of the distributor’s capacity, the supply chain turns out to be an autonomous switched system corresponding to the shipment policy of the distributor. The stability of the system studied is analyzed using switched system theory and discrete system control theory for the practical perspective. This study shows that the system will exhibit stable, periodic, and divergent behavior with different order policy parameters due to the switching mechanism within the system. The relationship between dynamics and cost is investigated, and insights are obtained about the control of the supply chain. [ABSTRACT FROM AUTHOR]

The association between obesity and the prognosis of ccRCC patients is conflicting. Herein, we conducted this study to examine the association between different obesity measurements and overall survival in patients with surgically treated ccRCC. In total, 342 patients with ccRCC were enrolled. The results indicate that the percentage of perirenal adipose tissue is superior to both BMI and percentage of visceral fat surface area for predicting overall survival. Introduction: Recently increasing evidence has suggested that obesity is associated with the development and prognosis of renal cell carcinoma. The aim of the study was to investigate the association between different obesity measurements and overall survival in patients with surgically treated clear cell renal cell carcinoma. Patients and Methods: The data of 342 consecutive patients who underwent radical or partial nephrectomy at Peking University People's Hospital from January 2009 to November 2014 were retrospectively reviewed. Median follow-up was 82 months. The association between different obesity measurements and overall survival was evaluated using the Kaplan-Meier method and Cox regression models. Results: In univariate Cox regression analyses, perirenal fat accumulation was significantly associated with overall survival (HR: 2.271; 95% CI: 1.311-3.935; P = .003), as well as age, sex, clinical manifestation, surgical option, tumor size, and grade. The other obesity measurements, including body mass index, waist circumference, total adipose tissue, visceral adipose tissue, and percentage of visceral adipose tissue, were not assessed as prognostic indicators of overall survival in this study (P > .05). After adjusting for age, sex, clinical manifestation, surgical option, tumor size, T stage, and tumor grade, perirenal fat accumulation was still identified as an independent predictor of overall survival (HR: 2.264; 95% CI: 1.305-3.926; P == .004). The results of Kaplan-Meier model also revealing that patients with higher percentage of perirenal fat showed poorer overall survival (P == .003). Conclusion: Higher percentage of perirenal adipose tissue is independently associated with increased mortality risk in surgically treated clear cell renal cell carcinoma. [ABSTRACT FROM AUTHOR]

Background. Antiretroviral therapy (ART) administered in clinical trial settings virtually eliminates the sexual transmission of human immunodeficiency virus (HIV) in serodiscordant couples, but effectiveness of treatment as prevention in the community is debated. Conflicting results from previous analyses in a Chinese cohort underscore the importance of determining effectiveness of ART delivered in resource limited settings. Methods. All available years of data (2006-2012) from local disease control records of HIV patients and their seronegative spouses in Henan Province, China, were analyzed using marginal structural Cox models to estimate the effect of ART in the initially infected partner his or her partner's HIV seroconversion risk. Results. We observed 157 seroconversion events in 4916 serosdiscordant couples, for an incidence rate of 0.59 cases per 100 person-years (PY) (95% confidence interval [CI], .51-.70). Of these, 84 occurred after the index partner had initiated ART (0.43/100PY; 95% CI, .35-.53) and 73, whereas index partners were untreated (5.87/100 PY; 95% CI, 4.65-7.42). In a marginal structural Cox model weighted for confounding and censoring, the hazard ratio (HR) for HIV transmission was 0.52 (95% CI, .34-.82). ART efficacy varied significantly by time period; least effective in the early phase from 2006 to 2008 (HR, 0.68; 95% CI, .34-1.36) but far more protective from 2009 onward (HR, 0.33; 95% CI, .20-.55). Conclusions. ART can provide HIV-infected persons in resource-limited setting substantial protection against sexual transmission. Effectiveness in the Henan cohort appears to have increased over time, suggesting that quality of care and service infrastructure may be integral to successful use of treatment for prevention. [ABSTRACT FROM AUTHOR]

ubmillimeter-Wave Limb-Emission Sounder-2 (SMILES-2) is a satellite mission proposed in Japan to probe the middle and upper-atmosphere (20–160 km). The main instrument is composed of 4-K cooled radiometers operating near 0.7 and 2 THz. It could measure the diurnal changes of the horizontal wind above 30 km, temperature above 20 km, ground-state atomic oxygen above 90 km, atmospheric density near the mesopause, as well as abundance of about 15 chemical species. In this study we have conducted simulations to assess the wind, temperature and density retrieval performance in the mesosphere and lower thermosphere (60–110 km) using the radiometer at 760 GHz. It contains lines of water vapor (H2O), molecular oxygen (O2) and nitric oxide (NO) that are the strongest signals measured with SMILES-2 at these altitudes. The Zeeman effect on the O2 line due to the geomagnetic field (B) is considered, otherwise, the retrieval errors would be underestimated by a factor of 2 above 90 km. The optimal configuration for the radiometer’s polarization is found to be vertical linear. The line-of-sight wind is retrieved with a precision of 2–5 m/s up to 90 km (30 m/s at 110 km) and a vertical resolution of 2.5 km. Temperature and atmospheric density are retrieved with a precision better than 5 K (30 K) and 7 % (20 %) up to 90 km (110 km), respectively. Errors induced by uncertainties on the vector B are mitigated by retrieving it. The retrieval of B is described as a side-product of the mission. At high-latitudes, precisions of 30–100 nT on the vertical component and 100–300 nT on the horizontal one could be obtained at 85 and 105 km (vertical resolution of 20 km). SMILES-2 could therefore provide the first measurements of B close to the electrojets' altitude, and the precision is enough to measure variations induced by solar storms in the auroral regions. [ABSTRACT FROM AUTHOR]

Background: Longitudinal studies of female sex workers (FSWs) are vulnerable to loss to follow-up (LTFU) due to this population's high mobility and low willingness to self-identify as FSWs. LTFU in cohort studies is a critical problem and may lead to bias in estimation of incidence and exposure-outcome associations. The aim of this study was to analyze LTFU and HIV incidence and their associated factors in a 9-year longitudinal study of FSWs in Kaiyuan, Yunnan Province, China. Methods: This analysis includes all HIV-1 seronegative FSWs who were recruited into a prospective study in Kaiyuan with at least one follow-up visit after enrollment from March 2006 to November 2013. Participants were visited in 6-month intervals after enrollment. Their demographic and behavioral data and blood specimens for HIV and sexual transmitted disease testing were collected at enrollment and at each follow-up visit. The administrative censoring date was December 31, 2014. Participants were considered LTFU if their last visit occurred 1 year or more before the administrative censoring date. Univariate and multivariable Cox regression models with time-independent variables were used to investigate the hazard ratios (HR) and 95 % confidence intervals (CI) of the factors associated with LTFU and HIV acquisition. Results: Of the 1158 FSWs, 950 were defined as LTFUs (LTFU rate: 29.69, 95 % CI: 27.85-31.62 per 100 person years [PYs]), and 33 experienced HIV seroconversions (cumulative incidence: 1.06, 95 % CI: 0.74-1.47 per 100 PYs). After adjustment, we found that FSWs who used drugs were less likely to be LTFU compared with non-drug users (adjust hazard ratio [AHR]= 0.62, 95 % CI: 0.51-0.76), though FSWs who used drug were associated with a higher risk of HIV acquisition (AHR = 3.06, 95 % CI: 1.49-6.30). Also, FSWs who always used condoms with clients in the previous month were associated with a higher risk of LTFU (AHR = 1.51, 95 % CI: 1.15-1.97), while they were negative associated with new HIV infection (AHR = 0.28, 95 % CI: 0.12-0.61). Conclusions: A high LTFU rate exists in the Kaiyuan FSW cohort study, and LTFU did not occur at random. Participants retained in the cohort tended to be at higher risk of HIV acquisition, which may result in an overestimate of the incidence of HIV infection from the Kaiyuan FSW cohort. [ABSTRACT FROM AUTHOR]