Reactions of Nickel(0)-Olefin Pincer Complexes with Terminal Alkynes: Cooperative C-H Bond Activation and Alkyne Coupling.

Metal-ligand cooperation can facilitate the activation of chemical bonds, opening reaction pathways of interest for catalyst development. In this context, olefins occupying the central position of a diphosphine pincer ligand (PC=CP) are emerging as reversible H atom acceptors, e.g., for H2 activation. Here, we report on the reactivity of nickel complexes of PC=CP ligands with a terminal alkyne, for which two competing pathways are observed. First, cooperative and reversible C-H bond activation generates a Ni(II) alkyl/alkynyl complex as the kinetic product. Second, in the absence of a bulky substituent on the olefin, two alkyne molecules are incorporated in the ligand structure to form a conjugated triene bound to Ni(0). The mechanisms of these processes are studied by density functional theory calculations supported by experimental observations.

New Synthesized Activating Transcription Factor 3 Inducer SW20.1 Suppresses Resistin-Induced Metabolic Syndrome.

Obesity is an emerging concern globally with increasing prevalence. Obesity is associated with many diseases, such as cardiovascular disease, dyslipidemia, and cancer. Thus, effective new antiobesity drugs should be urgently developed. We synthesized SW20.1, a compound that induces activating transcription factor 3 (ATF3) expression. The results of Oil Red O staining and quantitative real-time polymerase chain reaction revealed that SW20.1 was more effective in reducing lipid accumulation in 3T3-L1 preadipocytes than the previously synthesized ST32db, and that it inhibited the expression of the genes involved in adipogenesis and lipogenesis. A chromatin immunoprecipitation assay indicated that SW20.1 inhibited adipogenesis and lipogenesis by binding to the upstream promoter region of resistin at two sites (-2861/-2854 and -241/-234). In mice, the intraperitoneal administration of SW20.1 reduced body weight, white adipocyte weight in different regions, serum cholesterol levels, adipogenesis-related gene expression, hepatic steatosis, and serum resistin levels. Overall, SW20.1 exerts antiobesity effects by inhibiting resistin through the ATF3 pathway. Our study results indicate that SW20.1 is a promising therapeutic drug for diet-induced obesity.

Digital Healthy Diet Literacy and Fear of COVID-19 as Associated with Treatment Adherence and Its Subscales among Hemodialysis Patients: A Multi-Hospital Study.

Treatment adherence (TA) is a critical issue and is under-investigated in hemodialysis patients. A multi-center study was conducted from July 2020 to March 2021 on 972 hemodialysis patients in eight hospitals in Vietnam to explore the factors associated with TA during the COVID-19 pandemic. Data were collected, including socio-demographics, an End-Stage Renal Disease Adherence Questionnaire (ESRD-AQ), 12-item short-form health literacy questionnaire (HLS-SF12), 4-item digital healthy diet literacy scale (DDL), 10-item hemodialysis dietary knowledge scale (HDK), 7-item fear of COVID-19 scale (FCoV-19S), and suspected COVID-19 symptoms (S-COVID19-S). Bivariate and multivariate linear regression models were used to explore the associations. Higher DDL scores were associated with higher TA scores (regression coefficient, B, 1.35; 95% confidence interval, 95%CI, 0.59, 2.12; p = 0.001). Higher FCoV-19S scores were associated with lower TA scores (B, -1.78; 95%CI, -3.33, -0.24; p = 0.023). In addition, patients aged 60-85 (B, 24.85; 95%CI, 6.61, 43.11; p = 0.008) with "very or fairly easy" medication payment ability (B, 27.92; 95%CI, 5.89, 44.95; p = 0.013) had higher TA scores. Patients who underwent hemodialysis for ≥5 years had a lower TA score than those who received <5 years of hemodialysis (B, -52.87; 95%CI, -70.46, -35.28; p < 0.001). These findings suggested that DDL and FCoV-19S, among other factors, should be considered in future interventions to improve TA in hemodialysis patients.

Osteoporosis Risk in Hemodialysis Patients: The Roles of Gender, Comorbidities, Biochemical Parameters, Health and Diet Literacy.

Osteoporosis is a common bone health disorder in hemodialysis patients that is linked with a higher morbidity and mortality rate. While previous studies have explored the associated factors of osteoporosis, there is a lack of studies investigating the impacts of health literacy (HL) and digital healthy diet literacy (DDL) on osteoporosis. Therefore, we aimed to investigate the associations of HL, DDL, and other factors with osteoporosis among hemodialysis patients. From July 2020 to March 2021, a cross-sectional study was conducted on 675 hemodialysis patients in eight hospitals in Vietnam. The data were collected by using the osteoporosis self-assessment tool for Asians (OSTA) and the 12-item short form of the health literacy questionnaire (HLS-SF12) on digital healthy diet literacy (DDL) and hemodialysis dietary knowledge (HDK). In addition, we also collected information about the socio-demographics, the clinical parameters, the biochemical parameters, and physical activity. Unadjusted and adjusted multinomial logistic regression models were utilized in order to investigate the associations. The proportion of patients at low, medium, and high levels of osteoporosis risk was 39.6%, 40.6%, and 19.8%, respectively. In the adjusted models, women had a higher likelihood of osteoporosis risk than men (odds ratio, OR, 3.46; 95% confidence interval, 95% CI, 1.86, 6.44; p < 0.001; and OR, 6.86; 95% CI, 2.96, 15.88; p < 0.001). The patients with rheumatoid arthritis (OR, 4.37; 95% CI, 1.67, 11.52; p = 0.003) and stomach ulcers (OR, 1.95; 95% CI, 1.01, 3.77; p = 0.048) were more likely to have a higher likelihood of osteoporosis risk than those without. The patients who had a higher waist circumference (WC), HL, and DDL were less likely to have a medium level of osteoporosis risk (OR, 0.95; 95% CI, 0.92, 0.98; p = 0.004; OR, 0.92; 95% CI, 0.88, 0.96; p < 0.001; OR, 0.96; 95% CI, 0.93, 0.99; p = 0.017, respectively) and a high level of osteoporosis risk (OR, 0.93; 95% CI, 0.89, 0.97; p = 0.001; OR, 0.89; 95% CI, 0.84, 0.94; p < 0.001; OR, 0.95; 95% CI, 0.91, 0.99; p = 0.008, respectively) compared with a low level of osteoporosis risk and to those with a lower WC, HL, and DDL. In addition, higher levels of hemoglobin (Hb) (OR, 0.79; 95% CI, 0.66, 0.95; p = 0.014), hematocrit (Hct) (OR, 0.95; 95% CI, 0.92, 0.99; p = 0.041), albumin (OR, 0.91; 95% CI, 0.83, 0.99; p = 0.030), and education (OR, 0.37; 95% CI, 0.16, 0.88; p = 0.025) were associated with a lower likelihood of a high level of osteoporosis risk. In conclusion, osteoporosis risk is highly prevalent in hemodialysis patients. Improved HL, DDL, education, WC, albumin, Hb, and Hct levels should be considered in preventing hemodialysis patients from developing osteoporosis.

Kernel adaptive filtering-based phase noise compensation for pilot-free optical phase conjugated coherent systems.

We propose a kernel-based adaptive filtering method to suppress the phase noise (PN) arising from small deviations from ideal counter-phasing in the dual-pump fibre-based optical phase conjugation (OPC) of pilot-free quadrature-amplitude modulation (QAM) signals. We demonstrate experimentally and numerically that the proposed scheme achieves signal-to-noise ratio improvement over conventional PN compensation under optimised pump dithering settings in the OPC device and features no performance penalty across a range of pump-phase mismatch values, when it is used with a 16-QAM signal in an optical back-to-back configuration. We also illustrate the applicability of the method to the 64-QAM modulation format, and evaluate its performance in a transmission setup with mid-link OPC by means of numerical simulations.

Assessing the carbonisation temperatures recorded by ancient charcoals for δ13C-based palaeoclimate reconstruction.

Ancient charcoal fragments, produced by the use of wood as fuel in archaeological contexts or during natural or anthropic forest fires, persist in soil and sediments over centuries to millennia. They thus offer a unique window to reconstruct past climate, especially palaeo-precipitation regimes thanks to their stable carbon isotope composition. However, the initial δ13C of wood is slightly modified as a function of the carbonisation temperature. Carbonisation-induced 13C fractionation is classically investigated through a transfer function between experimental carbonisation temperatures and the carbon content. This approach assumes that the carbon content is conservative through time in ancient charcoals and neglects the potential impact of post-depositional oxidation occurring in soils and sediments. In the present study, we first show that post-depositional oxidation can lead to a large underestimation of past carbonisation temperatures, thereby minimising the estimation of carbonisation-induced 13C fractionations and possibly biasing δ13C-based climate reconstructions. Secondly, by combining carbon content, Fourier-transform infrared and Raman spectroscopy, we propose a new framework to assess the carbonisation temperatures registered in ancient charcoals. This new framework paves the way to reassessing δ13C-based climate reconstruction.

Localized recharge processes in the NE Mekong Delta and implications for groundwater quality.

Understanding recharge in the Mekong Delta is critical for the delta's groundwater resources, and requires the investigation of recharge processes at the local scale. In this study of the north eastern area of the Mekong Delta, time-series of environmental tracer data (δ18O, δ2H, major ions and 3H) and markers of rural pollution (NH4 and NO3) were used to highlight localized recharge and impacts on groundwater quality. Results highlighted new hydrological insights into recharge processes, including that the Pleistocene aquifer receives recent recharge (< 60 years), predominantly during high rainfall months (> 100 mm/month). However, due to shallow clay layers there are significant spatial variations in these recharge processes, which were observed in the seasonal fluctuation of groundwater δ18O values in groundwater. Wet season δ18O changes ranged from below analytical uncertainty (≤ 0.10 ‰) to up to 0.56 ‰, and the calculated fraction of rainfall contribution to the aquifer is ≤5 % to 16 %. Rainfall recharge via the acrisol soils results in low groundwater EC (20-55 µS/cm), acidic groundwater (pH 3.6-5.6), and may also have resulted in the low groundwater NO3 concentrations (≤ 5.3 mg NO3/L) at many sites due to adsorption, therefore delaying not reducing NO3 contamination. Site specific variations in nitrogen processes includes increased NO3 (to 29.7 mg/L) from fertiliser transfers or nitrification, and increased NH4 (to 1.4 mg/L) likely due to the recharge of irrigation waters. Unlike other recharge areas across the northern Mekong Delta, this north-eastern region provides a groundwater resource unaffected by arsenic contamination. Therefore, these results should inform on priority areas for protection from further contamination by rural anthropogenic activities.

The Associations of Suspected COVID-19 Symptoms with Anxiety and Depression as Modified by Hemodialysis Dietary Knowledge: A Multi-Dialysis Center Study.

During the COVID-19 pandemic, it is essential to evaluate hemodialysis patients' dietary knowledge, especially among those with COVID-19 related symptoms, in order to identify appropriate strategies in managing their mental health. The study's purposes were to test the psychometric properties of the hemodialysis dietary knowledge (HDK) scale, and to investigate the modifying impact of HDK on the associations of suspected COVID-19 symptoms (S-COVID-19-S) with anxiety and depression among hemodialysis patients. A cross-sectional study was conducted from July 2020 to March 2021 at eight hospitals across Vietnam. Data of 875 hemodialysis patients were analyzed, including socio-demographic, anxiety (the generalized anxiety disorder scale, GAD-7), depression (the patient health questionnaire, PHQ-9), S-COVID-19-S, HDK, health literacy, and digital healthy diet literacy. Confirmatory factor analysis (CFA) and logistic regression models were used to analyze the data. The HDK scale demonstrates the satisfactory construct validity with good model fit (Goodness of Fit Index, GFI = 0.96; Adjusted Goodness of Fit Index, AGFI = 0.90; Standardized Root Mean Square Residual, SRMR = 0.05; Root Mean Square Error of Approximation, RMSEA = 0.09; Normed Fit Index, NFI = 0.96; Comparative Fit Index, CFI = 0.96, and Parsimony goodness of Fit Index, PGFI = 0.43), criterion validity (as correlated with HL (r = 0.22, p < 0.01) and DDL (r = 0.19, p < 0.01), and reliability (Cronbach alpha = 0.70)). In the multivariate analysis, S-COVID-19-S was associated with a higher likelihood of anxiety (odds ratio, OR, 20.76; 95% confidence interval, 95%CI, 8.85, 48.70; p < 0.001) and depression (OR, 12.95; 95%CI, 6.67, 25.14, p < 0.001). A higher HDK score was associated with a lower likelihood of anxiety (OR, 0.70; 95%CI, 0.64, 0.77; p < 0.001) and depression (OR, 0.72; 95%CI, 0.66, 0.79; p < 0.001). In the interaction analysis, the negative impacts of S-COVID-19-S on anxiety and depression were mitigated by higher HDK scores (p < 0.001). In conclusion, HDK is a valid and reliable tool to measure dietary knowledge in hemodialysis patients. Higher HDK scores potentially protect patients with S-COVID-19-S from anxiety and depression during the pandemic.

[Predictive value of impedance of leadless pacemaker during implantation on trend changes of pacing threshold].

Objective: To explore the predictive value of the impedance measured during leadless pacemaker Micra implantation on the trend of changes of pacing threshold post implantation. Methods: This is a retrospective cross-sectional study. Patients who received implantation of leadless pacemaker Micra at the Second Xiangya Hospital of Central South University from December 2019 to August 2020 were enrolled. The clinical data and the intraoperative electrical parameters during leadless pacemaker implantation were collected. The impedance and pacing threshold data were analyzed at three time points: immediate release, 5-10 min after release, and after traction test. Receiver operating characteristic (ROC) curves and the area under the curve (AUC) were used to analyze the value of the impedance at immediate release on predicting the trend of changes of pacing threshold post implantation. Results: A total of 21 patients (mean age: (72.2±12.5) years, 12 males) were included. The impedance of 21 patients was (798.1±35.3) Ω immediately after implantation, (800.9±35.6) Ω after 5-10 minutes of release, and (883.6±31.7) Ω after traction test. Impedance was similar between the three time points (P>0.05). The threshold was (0.97±0.11) V/0.24 ms immediately after implantation, (0.95±0.12) V/0.24 ms at 5-10 min after the release, and (0.59±0.06) V/0.24 ms after the traction test. The threshold was significantly lower after the traction test than that immediately after release (P=0.003) and than that at 5-10 minutes after release (P=0.008), suggesting a decreased tendency of the threshold over time. According to the analysis of the ROC curve, the immediate impedance after the release ≥680 Ω could predict the ideal pacing threshold after the traction test (AUC=0.989, 95%CI 0.702-0.964, P<0.001), the prediction sensitivity was 87%, and the specificity was 100%. The pacing threshold would be not ideal with the immediate impedance ≤ 520 Ω (95%CI 0.893-1.000, P<0.001), the sensitivity was 100%, and the specificity was 80%. Conclusions: The impedance immediately after the release has predictive value for the changing trend of threshold post leadless pacemaker Micra implantation. Impedance ≥680 Ω immediately after release is often related with ideal pacing threshold after the traction test. In contrast, the impedance ≤ 520 Ω pacing is often related with unsatisfactory threshold after the traction test, therefore, it is recommended to find a new pacing site to achieve the impedance ≥680 Ω immediately after release during leadless pacemaker Micra implantation.

Distributed Raman Amplification for Fiber Nonlinearity Compensation in a Mid-Link Optical Phase Conjugation System.

In this paper, we review different designs of distributed Raman amplifiers which have been proposed to minimize the signal power profile asymmetry in mid-link optical phase conjugation systems. We demonstrate how the symmetrical signal power profiles along the fiber can be achieved using various distributed Raman amplification techniques in the single-span and more realistic multi-span circumstances. In addition, we show the theoretically predicted results of the Kerr nonlinear product reduction with different Raman techniques in mid-link optical phase conjugator systems, and then in-line/long-haul transmission performance using numerical simulations.

Raman Amplification Optimization in Short-Reach High Data Rate Coherent Transmission Systems.

We compared the transmission performances of 600 Gbit/s PM-64QAM WDM signals over 75.6 km of single-mode fibre (SMF) using EDFA, discrete Raman, hybrid Raman/EDFA, and first-order or second-order (dual-order) distributed Raman amplifiers. Our numerical simulations and experimental results showed that the simple first-order distributed Raman scheme with backward pumping delivered the best transmission performance among all the schemes, notably better than the expected second-order Raman scheme, which gave a flatter signal power variation along the fibre. Using the first-order backward Raman pumping scheme demonstrated a better balance between the ASE noise and fibre nonlinearity and gave an optimal transmission performance over a relatively short distance of 75 km SMF.

Digital compensation of imperfect pump counter-phasing induced phase distortion in optical phase conjugation of high-order QAM.

We propose a new two-stage digital signal processing scheme to suppress the phase distortion that arises from imperfect pump counter-phasing in a dual-pump fibre-based optical phase conjugation system. We demonstrate experimentally and numerically a signal-to-noise ratio improvement of more than 4 dB relative to conventional phase noise compensation, when the proposed scheme is used with 16/64/256 quadrature-amplitude modulation signals at pump-phase mismatch values as large as 8°.

Aging out of dependent coverage and the effects on the use of inpatient medical care.

We investigate the impact of losing health insurance coverage at age 26 due to aging out of the Affordable Care Act's dependent coverage on health insurance coverage rates and various indicators of inpatient medical care. We find that the probability of being covered under any type of health insurance plan decreases by 2.5-6.2 percentage points at age 26. However, the effects of this discrete change in health insurance coverage on inpatient medical care and related costs are insignificant.

Allelopathic Potential of Rice and Identification of Published Allelochemicals by Cloud-Based Metabolomics Platform.

The methanol extracts of nine popular cultivated Vietnamese rice cultivars (Oryza sativa L.cv. OM 2395, 5451, 6976, 380, 5930, 4498, 3536, N406, and 7347) were used to explore their allelopathic potential on barnyardgrass (Echinochola crus-galli L.). At 0.1 g mL-1, OM 5930, OM 4498, and OM 6976 correlatively possessed greatest phytotoxicity on barnyardgrass shoot (98.77%, 90.75%, and 87.17%) and root (99.39%, 92.83%, and 86.56%) growth. The following study aimed to detect previously-known allelochemicals in those rice using XCMS online cloud-based metabolomics platform. Twenty allelochemicals were semi-quantified and seven of them were detected predominantly and five was putatively confirmed in OM 5930 (mg/ 100g fresh rice) as salicylic acid (5.0076), vanillic acid (0.1246), p-coumaric acid (0.1590), 2,4-dimethoxybenzoic acid (0.1045), and cinnamic acid (3.3230). These compounds were active at concentrations greater than 0.5 mM and the average EC50 were 1.24 mM. The results indicated that OM 5930 may use as promising candidates in weed biological control for rice production.

The Enhancement of Leak Detection Performance for Water Pipelines through the Renovation of Training Data.

Leakage detection is a fundamental problem in water management. Its importance is expressed not only in avoiding resource wastage, but also in protecting the environment and the safety of water resources. Therefore, early leak detection is increasingly urged. This paper used an intelligent leak detection method based on a model using statistical parameters extracted from acoustic emission (AE) signals. Since leak signals depend on many operation conditions, the training data in real-life situations usually has a small size. To solve the problem of a small sample size, a data improving method based on enhancing the generalization ability of the data was proposed. To evaluate the effectiveness of the proposed method, this study used the datasets obtained from two artificial leak cases which were generated by pinholes with diameters of 0.3 mm and 0.2 mm. Experimental results show that the employment of the additional data improving block in the leak detection scheme enhances the quality of leak detection in both terms of accuracy and stability.