This paper presents a novel method for extracting the fetal ECG (FECG) from a single-lead abdominal signal. A dynamical model for a modified abdominal signal is proposed, in which both the maternal ECG (MECG) and the FECG are modeled, and then a parallel marginalized particle filter (par-MPF) is used for tracking the abdominal signal. Finally, the FECG and MECG are simultaneously separated. Several experiments are conducted using both simulated and clinical signals. The results indicate that the method proposed in this paper effectively extracts the FECG and outperforms other Bayesian filtering algorithms. Full article

As a primary basic gas in the atmosphere, atmospheric ammonia (NH₃) plays an important role in determining air quality, environmental degradation, and climate change. However, the limited ground observation currently presents a barrier to estimating ground NH₃ concentrations on a regional scale, thus preventing a full understanding of the atmospheric processes in which this trace gas is involved. This study estimated the ground NH₃ concentrations over China, combining the Infrared Atmospheric Sounding Interferometer (IASI) satellite NH₃ columns and NH₃ profiles from an atmospheric chemistry transport model (CTM). The estimated ground NH₃ concentrations showed agreement with the variability in annual ground NH₃ measurements from the Chinese Nationwide Nitrogen Deposition Monitoring Network (NNDMN). Great spatial heterogeneity of ground NH₃ concentrations was found across China, and high ground NH₃ concentrations were found in Northern China, Southeastern China, and some areas in Xinjiang Province. The maximum ground NH₃ concentrations over China occurred in summer, followed by spring, autumn, and winter seasons, which were in agreement with the seasonal patterns of NH₃ emissions in China. This study suggested that a combination of NH₃ profiles from CTMs and NH₃ columns from satellite obtained reliable ground NH₃ concentrations over China. Full article

Paeoniflorin (PF) is an active ingredient of Paeoniae Radix which possesses the neuroprotective effect. However, so far, the neuroprotective mechanism of PF has still not been fully uncovered. The Ca²⁺/Ca²⁺/calmodulin-dependent protein kinase II (CaMKII)/cAMP response element-binding (CREB) signaling pathway plays an important role in the intracellular signal transduction pathway involved in cell proliferation, cell survival, inflammation and metabolism. Herein, the neuroprotective roles of PF in the models of middle cerebral artery occlusion (MCAO) followed by reperfusion in rats and N-methyl-d-aspartic acid (NMDA)-induced excitotoxicity in primary hippocampal neurons were investigated. Moreover, we attempted to confirm the hypothesis that its protection effect is via the modulation of the Ca²⁺/CaMKI)/CREB signaling pathway. In this study, PF not only significantly decreased neurological deficit scores and infarct volume in vivo, but also improved neurons’ cell viability, and inhibited neurons’ apoptosis and intracellular Ca²⁺ concentration in vitro. Furthermore, PF significantly up-regulated p-CREB and p-CaMKII, and down-regulated calmodulin (CaM) in vivo and in vitro. The results indicate that the protective effect of PF on cerebral ischemia reperfusion injury is possible through regulating the Ca²⁺/CaMKII/CREB signaling pathway. Full article

Time-varying volatility is common in macroeconomic data and has been incorporated into macroeconomic models in recent work. Dynamic panel data models have become increasingly popular in macroeconomics to study common relationships across countries or regions. This paper estimates dynamic panel data models with stochastic volatility by maximizing an approximate likelihood obtained via Rao-Blackwellized particle filters. Monte Carlo studies reveal the good and stable performance of our particle filter-based estimator. When the volatility of volatility is high, or when regressors are absent but stochastic volatility exists, our approach can be better than the maximum likelihood estimator which neglects stochastic volatility and generalized method of moments (GMM) estimators. Full article

In this study, we selected natural polyploidy loach (diploid, triploid and tetraploid) and hybrid F₁ generation obverse cross (4 × 2) and inverse cross (2 × 4) by diploids and tetraploids as the research model. The MSAP (methylation-sensitive amplified polymorphism) reaction system was established by our laboratory to explore methylation levels and pattern diversification features at the whole genome level of the polyploidy loach. The results showed that the total methylation and full methylation rates decreased on increased ploidy individuals; moreover, the hemimethylation rate showed no consistent pattern. Compared with diploid loach, the methylation patterns of tetraploid sites changed 68.17%, and the methylation patterns of triploid sites changed 73.05%. The proportion of hypermethylation genes is significantly higher than the proportion of demethylation genes. The methylation level of reciprocal cross F₁ generation is lower than the male diploid and higher than the female tetraploid. The hemimethylation and total methylation rate of the cross hybrid F₁ generation is significantly higher than the orthogonal F₁ generation (p < 0.01). After readjusting, the methylation pattern of genome DNA of reciprocal hybrids changed 69.59% and 72.83%, respectively. Full article

Calcium overload is considered to be one of the mechanisms of cerebral ischemia. Ca²⁺ influx and Ca²⁺/calmodulin-dependent protein kinase II (CaMKII) and cAMP response element-binding protein (CREB) phosphorylation are considered to be involved in N-Methyl-d-aspartate (NMDA)-induced apoptosis process. This study investigated the neuroprotective effects of bryonolic acid (BA) in an NMDA-induced rat adrenal pheochromocytoma cell line (PC12) cells and the potential mechanism. PC12 was treated by NMDA to establish an excitotoxicity model. BA (110,100 and 1000 μM final concentration) was added to the medium 24 h prior to the addition of NMDA. Subsequently, a methyl thiazolyl tetrazolium (MTT) assay and a lactate dehydrogenase (LDH) release were performed. Ca²⁺ concentration was demonstrated using a scanning-dual wavelength fluorimetric method. In addition, protein and mRNA levels were determined via Western blot and real-time PCR. In the presence of BA, MTT assay and LDH assay showed that more cells were viable in comparison with the NMDA group. Moreover, the concentration of Ca²⁺ decreased with the addition of BA in culture. Furthermore, BA could upregulate protein expressions of Bcl-2, p-CREB, and p-CaMKII and downregulate protein expression of Bax. The mRNA results showed that the pattern of mRNA expression were similar to their respective protein levels. All these results indicate that BA protected PC12 cells against NMDA-induced apoptosis by inhibiting Ca²⁺ influx and regulating gene expression in the Ca²⁺-CaMKII-CREB signal pathway. Therefore, the present study supports the notion that BA may be a promising neuroprotective agent for the treatment of cerebral ischemia disease. Full article

In order to quickly and simultaneously obtain the chemical profiles and control the quality of the root of Polygonum multiflorum Thumb. and its processed form, a rapid qualitative and quantitative method, using ultra-high-performance liquid chromatography coupled with electrospray ionization-linear ion trap-Orbitrap hybrid mass spectrometry (UHPLC-LTQ-Orbitrap MSⁿ) has been developed. The analysis was performed within 10 min on an AcQuity UPLC™ BEH C₁₈ column with a gradient elution of 0.1% formic acid-acetonitrile at flow rate of 400 μL/min. According to the fragmentation mechanism and high resolution MSⁿ data, a diagnostic ion searching strategy was used for rapid and tentative identification of main phenolic components and 23 compounds were simultaneously identified or tentatively characterized. The difference in chemical profiles between P. multiflorum and its processed preparation were observed by comparing the ions abundances of main constituents in the MS spectra and significant changes of eight metabolite biomarkers were detected in the P. multiflorum samples and their preparations. In addition, four of the representative phenols, namely gallic acid, trans-2,3,5,4′-tetra-hydroxystilbene-2-O-β-d-glucopyranoside, emodin and emodin-8-O-β-d-glucopyranoside were quantified by the validated UHPLC-MS/MS method. These phenols are considered to be major bioactive constituents in P. multiflorum, and are generally regarded as the index for quality assessment of this herb. The method was successfully used to quantify 10 batches of P. multiflorum and 10 batches of processed P. multiflorum. The results demonstrated that the method is simple, rapid, and suitable for the discrimination and quality control of this traditional Chinese herb. Full article

Shexiang Tongxin dropping pill (STP) is a traditional Chinese medicine formula that consists of total saponins of ginseng, synthetic Calculus bovis, bear gall, Venenum bufonis, borneol and Salvia miltiorrhiza. STP has been widely used in China and Southeast Asia for the treatment of cardiovascular diseases. In this study, a qualitative analytical method using high performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry was developed for identification of the major constituents in STP. Based on the retention time and MS spectra, 41 components were identified by comparison with reference compounds and literature data. Moreover, using ultra-performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry in multiple-reaction monitoring mode, we quantified 13 of the identified constituents (ginsenoside Rg1, ginsenoside Rk3, cinobufagin, arenobufagin, bufalin, resibufogenin, tanshinone IIA, taurine, tauroursodeoxycholic acid, taurocholic acid, cholic acid, deoxycholic acid, and chenodeoxycholic acid). These results suggest that this new approach is applicable for the routine analysis and quality control of STP products and provides fundamental data for further in vivo pharmacokinetical studies. Full article

Alismatis Rhizoma (AMR) is a well-known natural medicine with a long history in Chinese medicine and has been commonly used for treating a wide range of ailments related to dysuria, edema, nephropathy, hyperlipidaemia, diabetes, inflammation as well as tumors in clinical applications. Most beneficial effects of AMR are attributed to the presence of protostane terpenoids, the major active ingredients of Alismatis Rhizoma (AMR). In this study, a systematic high performance liquid chromatography/diode-array detector/quadrupole-time-of-flight mass spectrometry (HPLC-DAD-Q-TOF MS) and ultra-performance liquid chromatography/triple quadrupole mass spectrometry (UPLC-QqQ MS) method was developed for qualitative and quantitative analyses of the major AMR triterpenoids. First, a total of 25 triterpenoid components, including 24 known compounds and one new compound were identified by comparison with UV spectra, molecular ions and fragmentation behaviors of reference standards or the literature. Second, an efficient method was established for the rapid simultaneous determination of 14 representative triterpenoids by UPLC-QqQ MS. Forty-three batches of AMR were analyzed with linearity (r, 0.9980–0.9999), intra-day precision (RSD, 1.18%–3.79%), inter-day precision (RSD, 1.53%–3.96%), stability (RSD, 1.32%–3.97%), repeatability (RSD, 2.21%–4.25%), and recovery (98.11%–103.8%). These results indicated that new approaches combining HPLC-DAD-Q-TOF MS and UPLC-QqQ MS are applicable in the qualitative and quantitative analysis of AMR. Full article

A simple, rapid and specific ultra-performance liquid chromatography-triple quadrupole mass spectrometry method was developed for the analysis of 29 bioactive components (10 phenolic acids, 16 flavonoids, and three iridoid glycosides) in Yinhua Kanggan tablet (YHKGT), a herbal prescription used for treating upper respiratory infections, fevers, coughs and pharyngalgia. The separation was successfully achieved using a Waters Cortecs UPLC C18 column (50 × 2.1 mm, 1.6 μm) and gradient elution with water-0.1% formic acid and acetonitrile. Polarity switching mode was used in the optimization of multiple reaction monitoring conditions. The analytical method was validated for linearity, precision and accuracy. Calibration curves for the 29 marker compounds showed good linear regression (r > 0.9982). The limits of detection (LOD) and limits of quantification (LOQ) for the 29 analytes were in the range of 0.03–4.99 ng/mL and 0.16–14.87 ng/mL, respectively. The relative standard deviation (RSD) values of intra-day precision, inter-day precision, repeatability, and stability were less than 2.79%, 4.87%, 4.18% and 4.71%, respectively. The recoveries of the 29 marker compounds were in the range of 94.67%–104.78% (RSD ≤ 4.72%). These results have shown that this developed method was efficient for the quality evaluation of YHKGT. Full article

The identification of the sources and fate of NO\(_{3}^{-}\) contaminants is important to protect the water quality of aquifer systems. In this study, NO\(_{3}^{-}\) contaminated groundwater from the drinking water wells in the Shijiazhuang area, China, was chemically (NO\(_{3}^{-}\)/Cl\(^{\rm{{-}}}\) ratio) and isotopically (\(δ\)\(^{\rm{15}}\)N\(_{\rm{NO3}}\), \(\delta\)\(^{\rm{18}}\)O\(_{\rm{NO3}}\) and \(\delta\)\(^{\rm{13}}\)C\(_{\rm{DOC}}\); \(\delta\)\(^{\rm{2}}\)H\(_{\rm{H2O}}\), \(\delta\)\(^{\rm{18}}\)O\(_{\rm{H2O}}\)) characterized to identify the sources of NO\(_{3}^{-}\) and address subsequent biogeochemical processes. The positive correlations between dominant anions and cations suggested that the dissolution of calcium carbonate and gypsum minerals was the most effective process in the groundwater. Elevated concentrations of NO\(_{3}^{-}\), Cl\(^{\rm{{-}}}\) and Mg\(^{\rm{2+}}\) could be related to the wastewater irrigation and usage of fertilizers. The natural water in the study area originated primarily from precipitation and experienced a limited extent of evaporation, as demonstrated by measurements of \(\delta\)\(^{\rm{2}}\)H\(_{\rm{H2O}}\) and \(\delta\)\(^{\rm{18}}\)O\(_{\rm{H2O}}\). A cross-plot of \(\delta\)\(^{\rm{15}}\)N\(_{\rm{NO3}}\) vs. \(\delta\)\(^{\rm{18}}\)O\(_{\rm{NO3}}\) gave an enrichment of the ¹⁵N isotope relative to the ¹⁸O isotope by a factor of 2. A further insight into the denitrification process was obtained by the synergistic changes in \(\delta\)\(^{\rm{13}}\)C\(_{\rm{DOC}}\) and \(\delta\)\(^{\rm{15}}\)N\(_{\rm{NO3}}\) values, confirming that a low extent of denitrification occurred. Nitrification processes were evaluated by means of \(\delta\)\(^{\rm{18}}\)O\(_{\rm{NO3}}\) and \(\delta\)\(^{\rm{18}}\)O\(_{\rm{H2O}}\). The initial \(\delta\)\(^{\rm{15}}\)N\(_{\rm{NO3}}\) value(s) of the NO\(_{3}^{-}\) source(s) were roughly estimated between 2‰ and 5‰. Based on the level of natural NO\(_{3}^{-}\), anthropogenic activities were considered the main reason for the elevated NO\(_{3}^{-}\) concentration of the shallow groundwater. NH\(_{4}^{+}\) fertilizers were the major source of NO\(_{3}^{-}\) in the non-wastewater irrigated area, while wastewater was regarded as the primary source of NO\(_{3}^{-}\) in the wastewater-irrigated area. A low content of NO\(_{3}^{-}\) in deep groundwater might mainly be influenced by precipitation and soil organic N that was involved in denitrification reactions. Some of the deep groundwater samples could have been contaminated by wastewater. The mixing process of multiple NO\(_{3}^{-}\) sources was identified as another important factor affecting the NO\(_{3}^{-}\) concentration of the groundwater in the study area. The combined use of \(\delta\)\(^{\rm{15}}\)N\(_{\rm{NO3}}\), \(\delta\)\(^{\rm{18}}\)O\(_{\rm{NO3}}\) and \(\delta\)\(^{\rm{13}}\)C\(_{\rm{DOC}}\) results and hydrochemical data (NO\(_{3}^{-}\)/Cl\(^{\rm{{-}}}\) ratios) gives an insight into the mixing effect of different NO\(_{3}^{-}\) sources and processes affecting NO\(_{3}^{-}\) concentration under conditions of intensive land-use activities. Full article