Blood Coagulation-Inspired Fibrin Hydrogel for Portable Detection of Thrombin Based on Personal Glucometer.

As one of the biomarkers of coagulation system-related diseases, the detection of thrombin is of practical importance. Thus, this study developed a portable biosensor based on a personal glucometer for rapid detection of thrombin activity. Fibrinogen was used for the detection of thrombin, and the assay principle was inspired by the blood coagulation process, where thrombin hydrolyzes fibrinogen to produce a fibrin hydrogel, and the amount of invertase encapsulated in the fibrin hydrogel fluctuates in accordance with the activity of thrombin in the sample solution. The quantitative assay is conducted by measuring the amount of unencapsulated invertase available to hydrolyze the substrate sucrose, and the signal readout is recorded using a personal glucometer. A linear detection range of 0-0.8 U/mL of thrombin with a limit of detection of 0.04 U/mL was obtained based on the personal glucometer sensing platform. The results of the selectivity and interference experiments showed that the developed personal glucometer sensing platform is highly selective and accurate for thrombin activity. Finally, the reliability of the portable glucometer method for rapid thrombin detection in serum samples was investigated by measuring the recovery rate, which ranged from 92.8% to 107.7%. In summary, the fibrin hydrogel sensing platform proposed in this study offers a portable and versatile means for detecting thrombin using a personal glucometer. This approach not only simplifies the detection process, but also eliminates the need for large instruments and skilled operators, and substantially reduces detection costs.

Chemoselective Synthesis of Unsymmetrical Dithioacetals through Sequential Carbene Insertion and Acetal Exchange of Acylsilanes and Thiols under Visible Light Irradiation.

Dithioacetals are a frequently used motif in synthetic organic chemistry, and most existing reports discuss only symmetrical dithioacetals. Examples of unsymmetrical dithioacetals are scarce, and few general methods for the selective synthesis of these compounds exists. An intriguing visible-light-induced strategy has been established in this work for sequential reactions of S-H insertion and acetal exchange between acylsilanes and two different thiols that deliver a wide variety of unsymmetrical dithioacetals in moderate yields. The unsymmetrical dithioacetals were obtained with high selectivity, and a great variety of functional groups were tolerated.

Value of human epididymis secretory protein 4 in differentiating malignant from benign pleural effusion: an analysis of two cohorts.

BACKGROUND: Lung cancer is the most common cause of malignant pleural effusion (MPE). Serum human epididymis secretory protein 4 (HE4) is a useful diagnostic marker for lung cancer. OBJECTIVE: This study aimed to evaluate the diagnostic accuracy of pleural fluid HE4 for MPE. DESIGN: A prospective, double-blind diagnostic test accuracy study. METHODS: Patients with undiagnosed pleural effusion were enrolled in two cohorts (Hohhot and Changshu). Electrochemiluminescence immunoassay was used to detect pleural fluid HE4. The diagnostic accuracy of HE4 was evaluated by a receiver operating characteristic (ROC) curve, and the net benefit of HE4 was assessed by a decision curve analysis (DCA). RESULTS: A total of 66 MPEs and 86 benign pleural effusions (BPEs) were enrolled in the Hohhot cohort. In the Changshu cohort, 26 MPEs and 32 BPEs were enrolled. In both cohorts, MPEs had significantly higher pleural fluid HE4 than BPEs. The area under the ROC curve (AUC) of HE4 was 0.73 (95% CI: 0.64-0.81) in the Hohhot cohort and 0.79 (95% CI: 0.67-0.91) in the Changshu cohort. At a threshold of 1300 pmol/L, HE4 had sensitivities of 0.44 (95% CI: 0.33-0.56) in the Hohhot cohort and 0.54 (95% CI: 0.35-0.73) in the Changshu cohort. The corresponding specificities were 0.90 (95% CI: 0.83-0.95) in the Hohhot cohort and 0.94 (95% CI: 0.84-1.00) in the Changshu cohort. In subgroup analyses, HE4 had an AUC (95% CI) of 0.78 (0.71-0.85) in exudates and an AUC of 0.69 (0.57-0.81) in patients with negative effusion cytology. The DCA revealed that HE4 determination had a net benefit in both cohorts. CONCLUSION: Pleural fluid HE4 has moderate diagnostic accuracy for MPE and has net benefit in pleural effusion patients with unknown etiology.

Determination of ibotenic acid and muscimol in species of the genus Amanita section Amanita from China.

The genus Amanita sect. Amanita harbors approximately 150 species in the world, and 27 species have been recognized in China. Some of the species in China have continuously caused poisoning. The responsible toxins should be ibotenic acid (IBO) and muscimol (MUS). However, species of the section Amanita containing IBO and MUS and their systematic positions are unclear. In this study, the contents of IBO and MUS in 84 samples of 24 species in section Amanita were detected using UPLC‒MS/MS, and the distribution of toxin-containing species in the molecular phylogeny was analyzed by the combined (ITS, nrLSU, RPB2, TUB2 and TEF1-α) dataset using maximum likelihood (ML) analysis and Bayesian inference (BI). Our results indicated that 10 of the 24 species contained IBO and MUS ranging from 0.6125 to 32.0932 and 0.0056-5.8685 g/kg dry weight, respectively. Among these 10 species, the toxins of eight species, including Amanita altipes, A. concentrica, A. flavopantherina, A. griseopantherina, A. pseudopantherina, A. rubrovolvata, A. subglobosa and A. sychnopyramis, were detected for the first time. In addition, the IBO and MUS contents of A. subglobosa in different growth stages showed that both toxins decreased in the mature stage. The phylogenetic analysis showed that all species of sect. Amanita from China were divided into 5 groups. And IBO- and MUS-containing species were gathered in clades Ⅰ and Ⅳ, but not all of the species in the two clades contain the toxins. No presence of IBO and MUS in the species of clades Ⅱ, Ⅲ and Ⅴ were confirmed.

Long-term stability of pleural fluid carcinoembryonic antigen and its effect on the diagnostic accuracy for malignant pleural effusion.

BACKGROUND: The in vitro stability assessment is essential for investigating the diagnostic accuracy of pleural biomarkers. This study aimed to investigate the long-term stability of pleural fluid carcinoembryonic antigen (CEA) at -80°C to -70°C. In addition, we analyzed the effects of frozen storage on the diagnostic accuracy of CEA for malignant pleural effusion (MPE). METHODS: Pleural fluid CEA of participants in two prospective cohorts were stored at -80°C to -70°C for 1-3 years. The CEA level in the stored specimen was measured with an immunoassay, and its level in the fresh specimen was extracted from medical records. The Bland-Altman method, Passing-Bablok regression, and Deming regression were used to analyze the agreement of CEA between the fresh and frozen pleural fluid. In addition, we used receiver operating characteristic (ROC) curves to evaluate the diagnostic accuracy of CEA in the fresh and frozen specimens for MPE. RESULTS: A total of 210 participants were enrolled. The median CEA levels in frozen and fresh pleural fluid specimens were similar (frozen, 2.32 ng/mL; fresh, 2.59 ng/mL; p < 0.01). The slopes and intercepts in the Passing-Bablok regression (intercept 0.01, slope 1.04) and Deming regression (intercept 0.65; slope 1.00) were not statistically significant (p > 0.05 for all). No significant difference was observed between the area under the ROC curves of CEA in the fresh and frozen specimens (p > 0.05 for all). CONCLUSION: Pleural fluid CEA is seemingly stable when stored at -80°C to -70°C for 1-3 years. Frozen storage does not significantly affect the diagnostic accuracy of CEA for MPE.

Enzyme-Regulated In Situ Formation of Copper Hexacyanoferrate Nanoparticles with Oxidase-Mimetic Behaviour for Colorimetric Detection of Ascorbate Oxidase.

In this study, a copper hexacyanoferrate nanoparticle with excellent oxidase-mimetic behaviour has been synthesized through a simple precipitation method. The synthesized copper hexacyanoferrate nanoparticle has intrinsic oxidase-like activity, which can catalyze the chromogenic reaction of 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate) through an O2•- reactive oxygen-species-participated process. On the other hand, K3[Fe(CN)6] can be reduced by ascorbic acid (AA) to produce K4[Fe(CN)6], thereby inhibiting the formation of the copper hexacyanoferrate nanoparticles. Furthermore, ascorbate oxidase (AAO) can catalyze the oxidation of AA to produce dehydroascorbic acid, which cannot reduce K3[Fe(CN)6]. Thus, a system for an AAO-regulated in situ formation of copper hexacyanoferrate nanoparticles was constructed by coupling a prepared copper hexacyanoferrate nanozyme with AA for the detection of AAO activity. This colorimetric sensing assay shows high sensitivity and selectivity for the detection of AAO activity (the limit of detection is 0.52 U/L) with a linear range of 1.1-35.7 U/L. Finally, the developed method was applied to detect the activity of AAO in normal human serum with a satisfactory sample spiked recovery (87.4-108.8%). In short, this study provides a good strategy for the construction of nanozyme-based multi-enzyme cascade-signal amplification assay.

Distributed Deep Fusion Predictor for a Multi-Sensor System Based on Causality Entropy.

Trend prediction based on sensor data in a multi-sensor system is an important topic. As the number of sensors increases, we can measure and store more and more data. However, the increase in data has not effectively improved prediction performance. This paper focuses on this problem and presents a distributed predictor that can overcome unrelated data and sensor noise: First, we define the causality entropy to calculate the measurement's causality. Then, the series causality coefficient (SCC) is proposed to select the high causal measurement as the input data. To overcome the traditional deep learning network's over-fitting to the sensor noise, the Bayesian method is used to obtain the weight distribution characteristics of the sub-predictor network. A multi-layer perceptron (MLP) is constructed as the fusion layer to fuse the results from different sub-predictors. The experiments were implemented to verify the effectiveness of the proposed method by meteorological data from Beijing. The results show that the proposed predictor can effectively model the multi-sensor system's big measurement data to improve prediction performance.

[Rapid Detection of Adenovirus in Fecal Samples by Capillary Electrophoresis-laser Induced Fluorescence and Microchip Capillary Electrophoresis-laser Induced Fluorescence].

OBJECTIVE: To establish a rapid and sensitive method based on polymerase chain reaction (PCR) combined with capillary electrophoresis-laser induced fluorescence (CE-LIF) and microchip capillary electrophoresis-laser induced fluorescence (MCE-LIF) for detecting adenoviruses in fecal samples. METHODS: The DNA of adenovirus in fecal samples were extracted by the commercial kits and the conserved region of hexon gene was selected as the target gene and amplified by PCR reaction. After labeling highly sensitive nucleic acid fluorescent dye SYBR Gold and SYBR Orange respectively, PCR amplification products were separated by CE and MCE under the optimized condition and detected by LIF detector. RESULTS: PCR amplification products could be detected within 9 min by CE-LIF and 6 min by MCE-LIF under the optimized separation condition. The sequenced PCR product showed good specificity in comparison with the prototype sequences from NCBI. The intraday and inter-day relative standard deviation (RSD) of the size (bp) of the target DNA was in the range of 1.14%-1.34% and 1.27%- 2.76%, respectively, for CE-LIF, and 1.18%-1.48% and 2.85%-4.06%, respectively, for MCE-LIF. The detection limits was 2.33 x 10(2) copies/mL for CE-LIF and 2.33 x 10(3) copies/mL for MCE-LIF. The two proposed methods were applied to detect fecal samples, both showing high accuracy. CONCLUSION: The two proposed methods of PCR-CE-LIF and PCR-MCE-LIF can detect adenovirus in fecal samples rapidly, sensitively and specifically.

[Effects of different applied nitrogen forms on pakchoi (Brassica chinensis) growth and its carbon and nitrogen accumulation].

A hydroponic experiment was conducted to study the effects of different applied nitrogen forms, i.e., ammonium, nitrate, glycine, glutamine, alanine, bovine serum albumin (BSA), mixture of glycine and nitrate, and mixture of BSA and nitrate, on the growth and carbon and nitrogen accumulation of pakchoi (Brassica chinensis). The significant differences were observed in the B. chinensis dry mass, fresh mass, carbon and nitrogen accumulation, and soluble protein, soluble sugar, and free amino acid contents among different treatments. In treatment nitrate, the fresh mass and dry mass of B. chinensis shoot and root were the highest; in treatment glycine, the root growth and the carbon and nitrogen accumulation of B. chinensis were promoted obviously; among the treatments glycine, glutamine, and alanine, treatment glutamine was more beneficial to the shoot growth and nitrogen accumulation. The nutritional effect of the applied nitrogen forms was in the order of nitrate, glutamine > mixture of glycine and nitrate, mixture of BSA and nitrate, glycine, ammonium > alanine, BSA, zero nitrogen. It was suggested that organic nitrogen could be used as a source of nitrogen nutrition for B. chinensis growth, and different nitrogen forms could have different physiological effects onthe B. chinensis plants.