A chitosan-based conductive double network hydrogel doped by tannic acid-reduced graphene oxide with excellent stretchability and high sensitivity for wearable strain sensors.

Conductive hydrogels usually suffer from weak mechanical properties and are easily destroyed, resulting in limited applications in flexible electronics. Concurrently, adding conductive additives to the hydrogel solution increases the probability of agglomeration and uneven dispersion issues. In this study, the biocompatible natural polymer chitosan was used as the network substrate. The rigid network employed was the Cit3-ion crosslinked chitosan (CS) network, and the MBA chemically crosslinked polyacrylamide (PAM) network was used as the flexible network. Tannic acid-reduced graphene oxide (TA-rGO), which has excellent conductivity and dispersibility, is used as a conductive filler. Thus, a CS/TA-rGO/PAM double network conductive hydrogel with excellent performance, high toughness, high conductivity, and superior sensing sensitivity was prepared. The prepared CS/TA-rGO/PAM double network conductive hydrogels have strong tensile properties (strain and toughness as high as 2009 % and 1045 kJ/cm3), excellent sensing sensitivity (GF value was 4.01), a wider strain detection range, high cycling stability and durability, good biocompatibility, and antimicrobial properties. The hydrogel can be assembled into flexible wearable devices that can not only dynamically detect human movements, such as joint bending, facial expression changes, swallowing, and saying, but also recognize handwriting and enable human-computer interaction.

A self-training algorithm based on the two-stage data editing method with mass-based dissimilarity.

A self-training algorithm is a classical semi-supervised learning algorithm that uses a small number of labeled samples and a large number of unlabeled samples to train a classifier. However, the existing self-training algorithms consider only the geometric distance between data while ignoring the data distribution when calculating the similarity between samples. In addition, misclassified samples can severely affect the performance of a self-training algorithm. To address the above two problems, this paper proposes a self-training algorithm based on data editing with mass-based dissimilarity (STDEMB). First, the mass matrix with the mass-based dissimilarity is obtained, and then the mass-based local density of each sample is determined based on its k nearest neighbors. Inspired by density peak clustering (DPC), this study designs a prototype tree based on the prototype concept. In addition, an efficient two-stage data editing algorithm is developed to edit misclassified samples and efficiently select high-confidence samples during the self-training process. The proposed STDEMB algorithm is verified by experiments using accuracy and F-score as evaluation metrics. The experimental results on 18 benchmark datasets demonstrate the effectiveness of the proposed STDEMB algorithm.

Heterozygous nonsense variants in laminin subunit 3α resulting in Ebstein's anomaly.

Ebstein's anomaly is a rare congenital heart disease characterized by tricuspid valve downward displacement and is associated with additional cardiac phenotypes such as left ventricle non-compaction. The genetic basis of Ebstein's anomaly has yet to be fully elucidated, although several genes (e.g., NKX2-5, MYH7, TPM1, and FLNA) may contribute to Ebstein's anomaly. Here, in two Ebstein's anomaly families (a three-generation family and a trio), we identified independent heterozygous nonsense variants in laminin subunit 3 α (LAMA3), cosegregated with phenotypes in families with reduced penetrance. Furthermore, knocking out Lama3 in mice revealed that haploinsufficiency of Lama3 led to Ebstein's malformation of the tricuspid valve and an abnormal basement membrane structure. In conclusion, we identified a novel gene-disease association of LAMA3 implicated in Ebstein's anomaly, and the findings extended our understanding of the role of the extracellular matrix in Ebstein's anomaly etiology.

Inorganic phosphate regulated high luminescence NaYF4:Yb3+, Er3+ as an iron ion fluorescent nanoprobe.

The iron ion in industrial circulating cooling water is an important indicator for early warning of equipment corrosion and control level. It is interesting to construct an upconversion luminescence iron ion nanoprobe with a common inorganic phosphate water treatment agent. Herein, inorganic phosphate sodium hexametaphosphate (SHMP) was used to regulate the morphology and functionalization of NaYF4:Yb3+, Er3+ upconversion luminescent nanoprobe (UCNPs) and applied to fluorometric detection of trace Fe(III) in water based on the fluorescence quenching which is caused by the selective coordination between hexametaphosphate on the surface of UCNPs and Fe(III). The structure, morphology, and luminous intensity of UCNPs were regulated by disodium hydrogen phosphate (ADSP), sodium tripolyphosphate (STPP) and sodium hexametaphosphate(SHMP). The UCNPs functionalized with SHMP has high sensitivity and selectivity for Fe(III) detection. The linear range and detection limit are 1.0-50 µM and 0.2 µM, respectively. The method has satisfactory results for the detection of trace Fe(III) in industrial circulating cooling water.

Hedgehog signalling controls sinoatrial node development and atrioventricular cushion formation.

Smoothened is a key receptor of the hedgehog pathway, but the roles of Smoothened in cardiac development remain incompletely understood. In this study, we found that the conditional knockout of Smoothened from the mesoderm impaired the development of the venous pole of the heart and resulted in hypoplasia of the atrium/inflow tract (IFT) and a low heart rate. The blockage of Smoothened led to reduced expression of genes critical for sinoatrial node (SAN) development in the IFT. In a cardiac cell culture model, we identified a Gli2-Tbx5-Hcn4 pathway that controls SAN development. In the mutant embryos, the endocardial-to-mesenchymal transition (EndMT) in the atrioventricular cushion failed, and Bmp signalling was downregulated. The addition of Bmp2 rescued the EndMT in mutant explant cultures. Furthermore, we analysed Gli2+ scRNAseq and Tbx5-/- RNAseq data and explored the potential genes downstream of hedgehog signalling in posterior second heart field derivatives. In conclusion, our study reveals that Smoothened-mediated hedgehog signalling controls posterior cardiac progenitor commitment, which suggests that the mutation of Smoothened might be involved in the aetiology of congenital heart diseases related to the cardiac conduction system and heart valves.

Construction of a novel electrochemical biosensor based on a mesoporous silica/oriented graphene oxide planar electrode for detecting hydrogen peroxide.

A constant magnetic field (CMF) was used to arrange the orientation of graphene oxide (GO) which was modified on a self-made screen-printed electrode. We evaluated the efficiency of this method for potential analytical application towards the sensing of hydrogen peroxide (H2O2). Mesoporous silica (MS)-encapsulated horseradish peroxidase (HRP) was immobilized on the electrode with vertically arranged GO to construct an H2O2 sensor (denoted as CMF/GO/HRP@MS). The linear range of the response of the CMF/GO/HRP@MS sensor to H2O2 was 0.1-235 µM, and the detection limit was as low as 0.01 µM. The results demonstrated that the vertical arrangement of GO resulting from the CMF on the electrode surface could increase the electron transfer rate. The excellent selectivity and anti-interference ability of this sensor to H2O2 in physiological samples may be attributed to the synergistic effect of mesoporous silica, GO and constant magnetic field.

Single-Cell RNA-Seq of the Developing Cardiac Outflow Tract Reveals Convergent Development of the Vascular Smooth Muscle Cells.

Cardiac outflow tract (OFT) is a major hotspot for congenital heart diseases. A thorough understanding of the cellular diversity, transitions, and regulatory networks of normal OFT development is essential to decipher the etiology of OFT malformations. We performed single-cell transcriptomic sequencing of 55,611 mouse OFT cells from three developmental stages that generally correspond to the early, middle, and late stages of OFT remodeling and septation. Known cellular transitions, such as endothelial-to-mesenchymal transition, have been recapitulated. In particular, we identified convergent development of the vascular smooth muscle cell (VSMC) lineage where intermediate cell subpopulations were found to be involved in either myocardial-to-VSMC trans-differentiation or mesenchymal-to-VSMC transition. Finally, we uncovered transcriptional regulators potentially governing cellular transitions. Our study provides a single-cell reference map of cell states for normal OFT development and paves the way for further studies of the etiology of OFT malformations at the single-cell level.

Separation of oil-water emulsion and adsorption of Cu(II) on a chitosan-cellulose acetate-TiO2 based membrane.

A modified cellulose acetate, modified chitosan, titanium dioxide membrane (MCA-MCS-TiO2) was prepared for oil-water emulsion separation and Cu(II) adsorption. This membrane shows excellent hydrophilicity and underwater oleophobicity. After being modified, the water contact angles of the membranes attain 13.7°, and the underwater oil contact angles reach 157.24°. The membrane exhibits high oil-water separation efficiency (99.4%) for cyclohexane, at the same time, the adsorption amount of Cu(II) on the membrane was measured. The variables include the ratio of modified cellulose to modified chitosan, the initial concentration of Cu(II), and the pH of Cu(II) solution. When pH = 7, the adsorption capacity of the membrane to Cu(II) reaches 220.67  mg g-1. When the concentration of Cu(II) solution is 1000 mg L-1, the adsorption efficiency is as high as 97.0%.

SGB-ELM: An Advanced Stochastic Gradient Boosting-Based Ensemble Scheme for Extreme Learning Machine.

A novel ensemble scheme for extreme learning machine (ELM), named Stochastic Gradient Boosting-based Extreme Learning Machine (SGB-ELM), is proposed in this paper. Instead of incorporating the stochastic gradient boosting method into ELM ensemble procedure primitively, SGB-ELM constructs a sequence of weak ELMs where each individual ELM is trained additively by optimizing the regularized objective. Specifically, we design an objective function based on the boosting mechanism where a regularization item is introduced simultaneously to alleviate overfitting. Then the derivation formula aimed at solving the output-layer weights of each weak ELM is determined using the second-order optimization. As the derivation formula is hard to be analytically calculated and the regularized objective tends to employ simple functions, we take the output-layer weights learned by the current pseudo residuals as an initial heuristic item and thus obtain the optimal output-layer weights by using the derivation formula to update the heuristic item iteratively. In comparison with several typical ELM ensemble methods, SGB-ELM achieves better generalization performance and predicted robustness, which demonstrates the feasibility and effectiveness of SGB-ELM.

A nickel nanoparticle/nafion-graphene oxide modified screen-printed electrode for amperometric determination of chemical oxygen demand.

A nickel nanoparticle/nafion-graphene oxide (NiNP/Nf-GO) modified screen-printed electrode (SPE) was developed for rapid and environmentally friendly electrochemical determination of chemical oxygen demand (COD). The morphology and the electrochemical performance of the SPEs with different surface modifications were investigated by scanning electron microscopy, electrochemical impedance spectroscopy, amperometry, and cyclic voltammetry, respectively. Interestingly, incorporation of graphene oxide as supporting materials to the NiNP/Nf-GO modified SPE enables high catalyst loading and electrode contact, leading to excellent electrocatalytic oxidation ability. A flow detection system was constructed based the newly designed NiNP/Nf-GO modified SPE with USB connection, a 3D-printed thin-layer flow cell (TLFC), and a peristaltic pump. The flow detection system showed an excellent performance for COD analysis with a linear detection range of 0.1~400 mg L-1 and a lower detection limit of 0.05 mg L-1 with an oxidation potential of 0.45 V. The system was further applied to determine the COD in surface water samples. The results were consistent with those obtained by using the standard method (ISO 6060). Graphical abstract A novel nickel nanoparticle/nafion-graphene oxide (NiNP/Nf-GO) modified screen-printed electrode (SPE) with excellent electrocatalytic oxidation ability was designed and fabricated. This electrode with USB connection was applied in a flow detection system equipped with a 3D-printed thin-layer flow cell and a peristaltic pump for environmentally friendly electrochemical determination of chemical oxygen demand.

A dual ammonia-responsive sponge sensor: preparation, transition mechanism and sensitivity.

PDMS-PU (polydimethylsiloxane-polyurethane) sponge decorated with In(OH)3 (indium hydroxide) and BCP (bromocresol purple) particles is shown to be a room-temperature ammonia sensor with high sensitivity and excellent reproducibility; it can accomplish real-time detection and monitoring of ammonia in the surrounding environment. The superhydrophobic and yellowish In(OH)3-BCP-TiO2-based ammonia-responsive (IBT-AR) sponge changes to a purple superhydrophilic one when exposed to ammonia. Notably, after reacting with ammonia, the sponge can recover its original wettability and color after heating in air. The wettability, color and absorption signal of IBT-AR sponge have been measured for sensing ammonia using the water contact angle, macroscopic observation and UV-vis absorption spectrometry, respectively. The minimum ammonia concentrations that can be detected by the sponge wettability, color and absorption signal are 0.5%, 1.4 ppm and 50 ppb, respectively. This kind of sponge with smart wettability and color is a promising new ammonia detector.

A New Electrochemical System Based on a Flow-Field Shaped Solid Electrode and 3D-Printed Thin-Layer Flow Cell: Detection of Pb2+ Ions by Continuous Flow Accumulation Square-Wave Anodic Stripping Voltammetry.

Here we describe a new and sensitive flow electrochemical detection system that employs a novel flow-field shaped solid electrode (FFSSE). The system was constructed with a 3D-printed thin-layer flow cell (TLFC) and a flat screen-printed FFSSE with USB connection. This interface facilitates continuous flow accumulation square-wave anodic stripping voltammetry (ASV). The flow distribution in the working space of TLFC was simulated using the finite element method (FEM) and the shape and configuration of electrodes were optimized accordingly. We demonstrated the electrochemical determination of Pb2+ using this newly designed TLFC-FFSSE detection system without removal of oxygen from samples. This TLFC-FFSSE based system showed an attractive stripping voltammetric performance compared to a traditional ASV based method. A linear range for detection of Pb2+ was found to be 0.5-100 µg/L (0.5 to 100 ppb) and a detection limit of 0.2 µg/L (0.2 ppb) was achieved in the presence of bismuth as codeposition metal. The system was further applied to detect Pb2+ in biological broths of methane fermentation. The electrochemical detection results were consistent with that obtained from atomic fluorescence spectroscopy (AFS) analysis and the average recovery was found to be 95.5-106.5% using a standard addition method. This new flow electrochemical detection system showed better sensitivity and reproducibility compared to a traditional ASV based method. Such a system offers great potential for on-site and real-time detection of heavy metals where compact, inexpensive, robust, and low-volume analysis is required.

A strategy for the evaluation of an analytical approach for selected pesticide residues in complex agricultural product matrices-A case study of leek.

In order to choose a sensitive, selective, simple, rapid, cost-effective and reliable analytical method for a given complex sample, a strategy was proposed for the evaluation of an analytical approach to determining multi-pesticide residue in complex agricultural product matrices, using leek as an example. In this work, the matrix effect of most of pesticides were in the range of -50% to -90%. A simple thin layer chromatography (TLC) was used to evaluate the effect of cleanup. The results agree well with that of matrix effect described above. More than 91% of the investigated compounds achieved recoveries were in the range of 70-120%. The limits of detection and limits of quantification were in the range of 0.1-3.5ng/g and 0.4-11.5ng/g, respectively. The strategy can be used to analyze multi-pesticide residue or related chemicals in diverse agricultural product matrices to provide technical guidance in choosing an analytical approach.

FGF signaling is required for anterior but not posterior specification of the murine liver bud.

BACKGROUND: The definitive endoderm arises as a naive epithelial sheet that produces the entire gut tube and associated organs including the liver, pancreas and lungs. Murine explant studies demonstrate that fibroblast growth factor (FGF) signaling from adjacent tissues is required to induce hepatic gene expression from isolated foregut endoderm. The requirement of FGF signaling during liver development is examined by means of small molecule inhibition during whole embryo culture. RESULTS: Loss of FGF signaling before hepatic induction results in morphological defects and gene expression changes that are confined to the anterior liver bud. In contrast the posterior portion of the liver bud remains relatively unaffected. Because FGF is thought to act as a morphogen during endoderm organogenesis, the ventral pancreas was also examined after FGF inhibition. Although the size of the ventral pancreas is not affected, loss of FGF signaling results in a significantly higher density of ventral pancreas cells. CONCLUSIONS: The requirement for FGF-mediated induction of hepatic gene expression differs across the anterior/posterior axis of the developing liver bud. These results underscore the importance of studying tissue differentiation in the context of the whole embryo.

Perovskite LaTiO3-Ag0.2 nanomaterials for nonenzymatic glucose sensor with high performance.

In this paper, a nonenzymatic glucose biosensor based on perovskite LaTiO3-Ag0.2(LTA) modified electrode was presented. The morphology and the composition of the perovskite LaTiO3-Ag0.2 nanomaterials were characterized by using scanning electron microscopy (SEM) and X-ray diffraction (XRD) respectively. The LaTiO3-Ag0.2(LTA) composite was investigated by electrochemical characterization using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under optimal conditions, CV and chronoamperometry (I-t) study revealed that, compared with the bare glassy carbon electrode (GCE), the modified electrode showed a remarkable increase in the efficiency of the electrocatalytic oxidation of glucose, starting at around +0.70 V (vs. Ag/AgCl). The prepared sensor exhibited a high sensitivity of 784.14 µAmM⁻¹ cm⁻², a low detection limit of 2.1×10⁻7 M and a wide linear range from 2.5 µM to 4 mM (R=0.9997). More importantly, the LTA modified electrode was also relatively insensitive to commonly interfering species such as ascorbic acid (AA), uric acid (UA), dopamine (DA) in high potential. Moreover, the nonenzymatic sensor was applied to the determination of glucose in human serum samples and the results were in good agreement with clinical data. Electrodes modified with perovskite nanomaterials are highly promising for nonenzymatic electrochemical detection of glucose because of their high sensitivity, fast response, excellent stability and good reproducibility.

Smad7 is a transforming growth factor-beta-inducible mediator of apoptosis in granulosa cells.

OBJECTIVE: To determine the functional role of Smad7 in granulosa cells. DESIGN: Granulosa cell culture and molecular biological techniques were used to investigate regulation and function of Smad7. SETTING: Research laboratory. ANIMAL(S): C57bl/j hybrid mouse. INTERVENTION(S): Primary mouse granulosa cells were isolated and grown in culture for all messenger RNA expression experiments. Smad7 promoter constructs were evaluated with a luciferase reporter system in SIGC cells to determine sites activating Smad7 expression. MAIN OUTCOME MEASURE(S): Overexpression (Smad7 complementary DNA) and downregulation (Smad7 small interfering RNA) of Smad7 in primary mouse granulosa cells were used to evaluate the functional role of Smad7 in granulosa cells. RESULT(S): Smad7 expression was upregulated by treatment with transforming growth factor-ß (TGF-ß) but not activin or activation of the cyclic adenosine monophosphate pathway. The promoter of Smad7 was activated by TGF-ß. Truncation of the promoter or mutation of the Smad response element at -141 eliminated TGF-ß activation of the promoter. Smad3 was not specifically required for TGF-ß-stimulated expression of Smad7, though activation of the TGFBR1 receptor was. When Smad7 was overexpressed in granulosa cells, apoptosis was markedly increased. When Smad7 expression was reduced with small interfering RNA, then the TGF-ß-induced apoptosis was blocked. CONCLUSION(S): Smad7 mediates apoptosis induced by TGF-ß in mouse granulosa cells, suggesting that dysregulation of Smad7 could impair folliculogenesis.

(E)-5-(3,5-Dimethyl-phen-yl)-N-[4-(methyl-sulfan-yl)benzyl-idene]-1,3,4-thia-diazol-2-amine.

The title compound, C(18)H(17)N(3)S(2), was synthesized by the reaction of 5-(3,5-dimethyl-phen-yl)-1,3,4-thia-diazol-2-amine and 4-(methyl-sulfan-yl)benzaldehyde. An intra-molecular C-H⋯S hydrogen bond results in the formation of a planar (r.m.s. deviation = 0.003 Å) five-membered ring. In the crystal structure, inter-molecular C-H⋯N hydrogen bonds link the mol-ecules to form layers parallel to (011).

Myofibril-inducing RNA (MIR) is essential for tropomyosin expression and myofibrillogenesis in axolotl hearts.

The Mexican axolotl, Ambystoma mexicanum, carries the naturally-occurring recessive mutant gene 'c' that results in a failure of homozygous (c/c) embryos to form hearts that beat because of an absence of organized myofibrils. Our previous studies have shown that a noncoding RNA, Myofibril-Inducing RNA (MIR), is capable of promoting myofibrillogenesis and heart beating in the mutant (c/c) axolotls. The present study demonstrates that the MIR gene is essential for tropomyosin (TM) expression in axolotl hearts during development. Gene expression studies show that mRNA expression of various tropomyosin isoforms in untreated mutant hearts and in normal hearts knocked down with double-stranded MIR (dsMIR) are similar to untreated normal. However, at the protein level, selected tropomyosin isoforms are significantly reduced in mutant and dsMIR treated normal hearts. These results suggest that MIR is involved in controlling the translation or post-translation of various TM isoforms and subsequently of regulating cardiac contractility.

(S)-Ethyl 2-[4-(6-chloro-quinoxalin-2-yl-oxy)phen-oxy]propanoate.

In the mol-ecule of the title compound, C(19)H(17)ClN(2)O(4), the quinoxaline ring system is planar [maximum deviation = 0.013 (3) Å] and oriented at a dihedral angle of 80.18 (3)° with respect to the benzene ring. In the crystal structure, inter-molecular C-H⋯N inter-actions link mol-ecules into chains. π-π contacts between the quinoxaline systems [centroid-centroid distance = 3.654 (1) Å] may further stabilize the structure.

2-Nitro-N-propyl-benzamide.

The title compound, C(10)H(12)N(2)O(3), contains three mol-ecules in the asymmetric unit. In the crystal structure, inter-molecular N-H⋯O inter-actions link the mol-ecules into chains along the b axis. The crystal structure is consolidated by weak C-H⋯π inter-actions.