Research on distributed strain monitoring of a bridge based on a strained optical cable with weak fiber Bragg grating array.

The foundation of an intelligent highway network is the construction of a high-density distributed strain monitoring system, which is based on sensing elements that can sensitively capture external information. In this research, the development and application for the structure of a novel strained optical fiber cable based on the weak fiber Bragg grating (wFBG) arrays are discussed. A modulation and demodulation solution of wavelength division multiplexing combined with time division multiplexing is developed by utilizing the property by which the wavelength of the strained optical fiber cable is periodically switched. Further, the strain transfer model of the optical cable is analyzed hierarchically using the theory of elasticity. The strain transfer coefficients of the overhanging region and the gluing region are combined to deduce the sensitivity model of the strained optical fiber cable. Moreover, the finite element technique is integrated to optimize the structural parameters of the optical cable for high-sensitivity or large-scale range. The strained optical fiber cable based on wFBG arrays is applied to a steel-concrete composite bridge. The static and dynamic loading tests show that the sensing optical cable can be monitored for strain variation in order to realize the functions of lane identification, weighing vehicle tonnage as well as velocity discrimination.

Maternal Gestational Diabetes Mellitus and Congenital Heart Disease in Offspring: A Meta-Analysis.

Maternal diabetes has been related to an increased risk of congenital heart disease (CHD) in offspring. However, inconsistent results were retrieved for studies evaluating the association between gestational diabetes mellitus (GDM) and CHD in offspring. We therefore performed a systematic review and meta-analysis for comprehensive investigation. Observational studies were identified by searching PubMed, Embase, and Web of Science according to the aim of the meta-analysis. A randomized-effects model was used to pool the data by incorporating the influence of potential heterogeneity. Twenty-three observational studies, involving 46953078 mother-child pairs, were available for the meta-analysis. Among them, 2131800 mothers were diagnosed as GDM and 214379 newborns had CHD. Overall, maternal GDM was associated with a higher incidence of CHD in offspring [odds ratio (OR): 1.32, 95% confidence interval (CI): 1.21 to 1.45, p<0.001; I2=62%]. Sensitivity analysis limited to studies with adjustment of maternal age and other potential confounding factors showed similar results (OR: 1.40, 95% CI: 1.30 to 1.51, p<0.001; I2=47%). Subgroup analysis suggested that the association between maternal GDM and CHD in offspring was not significantly affected by methods for diagnosis of GDM, methods for confirmation of CHD, or study quality scores (p for subgroup difference all>0.05). Subsequent analysis according to types of CHD showed that maternal GDM was associated with higher risks of atrial septal defect, ventricular septal defect, and Tetralogy of Fallot. Maternal GDM may be associated with a higher risk of CHD in offspring.

Vehicle identification using deep learning for expressway monitoring based on ultra-weak FBG arrays.

A deep learning with knowledge distillation scheme for lateral lane-level vehicle identification based on ultra-weak fiber Bragg grating (UWFBG) arrays is proposed. Firstly, the UWFBG arrays are laid underground in each expressway lane to obtain the vibration signals of vehicles. Then, three types of vehicle vibration signals (the vibration signal of a single vehicle, the accompanying vibration signal, and the vibration signal of laterally adjacent vehicles) are separately extracted by density-based spatial clustering of applications with noise (DBSCAN) to produce a sample library. Finally, a teacher model is designed with a residual neural network (ResNet) connected to a long short-term memory (LSTM), and a student model consisting of only one LSTM layer is trained by knowledge distillation (KD) to satisfy the real-time monitoring with high accuracy. Experimental demonstration verifies that the average identification rate of the student model with KD is 95% with good real-time capability. By comparison tests with other models, the proposed scheme shows a solid performance in the integrated evaluation for vehicle identification.

Free-Standing Carbon Nanofiber Composite Networks Derived from Bacterial Cellulose and Polypyrrole for Ultrastable Potassium-Ion Batteries.

Carbon materials derived from bacterial cellulose have been studied in lithium-ion batteries due to their low cost and flexible characteristics. However, they still face many intractable problems such as low specific capacity and poor electrical conductivity. Herein, bacterial cellulose is used as the carrier and skeleton to creatively realize the composite of polypyrrole on its nanofiber surface. After carbonization treatment, three-dimensional carbon network composites with a porous structure and short-range ordered carbon are obtained for potassium-ion batteries. The introduction of nitrogen doping from polypyrrole can increase the electrical conductivity of carbon composites and provide abundant active sites, improving the comprehensive performance of anode materials. The carbonized bacterial cellulose@polypyrrole (C-BC@PPy) anode exhibits a high capacity of 248 mA h g-1 after 100 cycles at 50 mA g-1 and a capacity retention of 176 mA h g-1 even over 2000 cycles at 500 mA g-1. Combined with density functional theory calculations, these results indicate that the capacity of C-BC@PPy is contributed by N-doped and defect carbon composite materials as well as pseudocapacitance. This study provides a guideline for the development of novel bacterial cellulose composites in the energy storage field.

Research on a fiber Bragg grating hydrostatic level based on elliptical ring for settlement deformation monitoring.

The hydrostatic leveling system based on the connecting pipe principle has important application value in the field of settlement monitoring. In this paper, a novel fiber Bragg grating (FBG) hydrostatic level based on elliptical ring is proposed. In this study, the vertical and lateral deformations of elliptical ring under concentrated force is analyzed using force method and Mohr integral. Thereby, the deformation-coordination equation of the elliptical ring and the diaphragm is constructed. The temperature self-compensation model for the elliptical ring is established from the three levels of material, structure, and device. A complete set of theories and methods for the designed FBG hydrostatic level is proposed. Furthermore, the tests of the sensitivity, resolution, and temperature self-compensation for the encapsulated sensors are carried out by multi-point loading experiment. The experimental results show that in the range of 0∼100 mm, the sensitivity of the sensor is close to the theoretical analysis, which is about 12 pm/mm. The effective resolution can reach 0.025∼0.05 mm, with the sensitivity coefficient to temperature as low as only 1.46 pm/°C.

Child inflammatory myofibroblastic tumor of the kidney misdiagnosed as Wilms' tumor: case report.

Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal tumor with recurrent potential, most commonly occurring in the lung but rarely in the kidney with nonspecific clinical symptoms and radiographic features, thus may be misdiagnosed as primary malignant lesions. We described a 6-year-old boy with renal IMT misdiagnosed as Wilms' tumor and then treated with right nephrectomy. It should be emphasized that in addition to the most common renal tumors in children, IMT should also be taken as a differential diagnosis. It is therefore mandatory to carry out clinical interpretation, careful histologic examination, and immunohistochemical studies collectively to make solid diagnosis.

Variation of blending ratio and drying temperature optimize the physical properties and compatibility of HPMC/curdlan films.

Hydroxypropyl methylcellulose (HPMC) and curdlan (CL) were used to prepare uniform films. The influence of the composition ratios and drying temperature on the microstructures, compatibility and physical performance of HPMC/CL films were studied. The crystalline peaks corresponding to CL component of HPMC/CL films increased with the increasing CL content. Increasing CL content resulted in increased hydrogen bonds in HPMC/CL film, reduced transmittance at 500 nm, oxygen permeability and water solubility of the HPMC/CL films. Higher drying temperature led to increased phase separation and decreased physical properties of pure HPMC film, and led to increased compatibility, cross-section smoothness, oxygen barrier property and mechanical properties of pure CL and blending films.

A self-crosslinking, double-functional group modified bacterial cellulose gel used for antibacterial and healing of infected wound.

Cellulose/chitosan composite, as a mature commercial antibacterial dressing, is an important type of wound repair material. However, how to achieve the perfect compound of two components and improve antibacterial activity is a major, lingering issue. In this study, a bifunctional group modified bacterial cellulose (DCBC) was prepared by carboxymethylation and selective oxidation. Further, the chitosan (CS) was compounded in the network of DCBC by self-crosslinking to form dialdehyde carboxymethyl bacterial cellulose/chitosan composites (S-DCBC/CS). The aldehyde group can react with amino of CS by Schiff base reaction. The carboxyl group of DCBC and the amorphous distribution of CS molecular chains increase the antimicrobial properties of composites. The bacteriostatic rate of composites could be higher than 95%. Bacteria can be attracted onto the surface of composites, what we call it "directional adhesion antibacterial effects". In particular, a kind of large animal wound model, deep Ⅱ degree infected scald of Bama miniature pig, was used to research the antimicrobial and healing properties of materials. The S-DCBC/CS can effectively inhibit bacterial proliferation of wound and kill the bacteria. The wound healing rate of S-DCBC/CS was up to 80% after three weeks. The composites show better antibacterial and promoting concrescence effects than traditional chitosan dressings.

Effect of Curdlan on the Rheological Properties of Hydroxypropyl Methylcellulose.

This work focuses on the effect of curdlan (CL) on dynamic viscoelastic property, thermal reversible property, viscosity, and the fluid types of hydroxypropyl methylcellulose (HPMC) at different temperatures. Compared to the blends at 25 °C, the blends had a smaller linear viscoelastic region (LVR), a higher gel strength, and larger storage modulus (G') and loss modulus (G") values at 82 °C. G', G", gel strength, and viscosity increased with the increase of CL. Repeated temperature sweep led to increased G' and G" of HPMC/CL blends. For HC6 and HC8, the gel formation temperature of the repeated temperature sweep was significantly lower than that of the first sweep. The samples at 82 °C, except for the sample with 8% CL, were all yield-shear thinning fluids, and the samples at 40 °C were shear thinning fluids. The creation of HPMC/CL and its rheological research might provide some methodological references for the study of other thermal-thermal gel blends.

Flame Retardancy and Thermal Behavior of an Unsaturated Polyester Modified with Kaolinite-Urea Intercalation Complexes.

Organic modified kaolinite-urea intercalation complex (KUIC) was prepared using dimethyl sulfoxide (DMSO) as the precursor of kaolinite intercalation. Its structure was characterized by Fourier transform infrared (FTIR) and X-ray diffraction (XRD). Subsequently, as a synergistic agent, KUIC was combined with flame retardant ammonium polyphosphate (APP) to improve the flame retardant and smoke suppression performance of unsaturated polyester (UP) resin. A cone calorimeter (CONE) was used to study its flame retardancy and smoke suppression, and a scanning electron microscope (SEM) and thermogravimetry (TG) were used to study the micro morphology of the char and flame retardant mechanism. The results show that 12 phr of APP and 3 phr of KUIC were doped into UP to obtain a 28.0% limiting oxygen index (LOI) value. Compared with UP, the heat release rate and smoke production of UP/APP/KUIC composites were greatly decreased. Meanwhile, KUIC indeed enhanced the mechanical properties of UP.

Comparison of Carotid Atherosclerosis between Patients at High Altitude and Sea Level: A Chinese Atherosclerosis Risk Evaluation Study.

OBJECTIVES: To investigate the differences in characteristics of carotid plaques between patients Xining at high altitude and Jinan at sea level using magnetic resonance (MR) imaging. METHODS: Subjects were recruited from a cross-sectional, observational, multicenter imaging study of CARE-II study. Forty-nine (mean age 63.3 ± 12.0 years, 33 males) and 51 (mean age 64.5 ± 12.0 years, 34 males) patients were recruited from a site located in a high altitude region and a site located near sea level, respectively. All patients underwent multicontrast MR vessel wall imaging for carotid arteries on 3.0 T MR scanner. The carotid plaques features were compared between 2 patient groups. RESULTS: Compared with patients at sea level, those at high altitude had significantly greater lumen area (58.5 ± 17.8 mm2 versus 50.0 ± 19.6 mm2, P = .008), smaller maximum normalized wall index (48.6% ± 14.2% versus 57.8% ± 16.3%, P = .002), and smaller percentage volume of calcium (0.9% versus 5.6%, P < .001) in the symptomatic carotid artery. After adjustment for clinical risk factors including age, sex, systolic blood pressure, LDL-C, and statin use, these differences in plaque morphology and composition remained statistically significant. After further adjustment for normalized wall index as a measure of plaque burden, percentage volume of calcification was still significantly smaller in patients at high altitude area than that in patients at sea level area (P = .047). CONCLUSION: Symptomatic subjects from a high altitude area have lower plaque burden and less calcification in the carotid artery compared to those from an area near sea level.

Microstructures, physical and sustained antioxidant properties of hydroxypropyl methylcellulose based microporous photophobic films.

Hydroxypropyl methylcellulose (HPMC)/sodium citrate (SC)/lipid tea polyphenol (LTP) photophobic films with different pore sizes from micron scale to nanometer scale were prepared by regulating the SC content (1-7%). The microstructures, physical and sustained antioxidant properties of these films were studied by using wide angel X-ray diffraction, small angle X-ray scattering (SAXS), scanning electron microscope, whiteness meter, ultraviolet spectrophotometer, texture analyzer and peroxide value test. Composite films with higher SC content showed larger pore size and whiteness. With the increasing SC content, crystallinity first increased then decreased. The addition of SC decreased the Ds (surface fractal dimension) value, smoothness of the cross-section structure, tensile strength, elongation and modulus of composite films. HPMC/SC/LTP microporous films possessed control-release property in oil system, reflected by the lowest peroxide value of peanut oil enclosed in film with 3% SC during three weeks, meaning this film showed the best sustained antioxidant property.

In situ synthesis of bacterial cellulose/copper nanoparticles composite membranes with long-term antibacterial property.

Bacterial cellulose (BC), with unique structure and properties, has attracted much attention in the biomedical field, especially in using as wound dressing. However, pure BC lacks the antimicrobial activity, which limits its application in wound healing. To solve this problem, copper nanoparticles (Cu NPs) loaded BC membranes were fabricated by using in situ chemical reduction method. The morphology and chemical composition of the composite membranes were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA). The results showed that Cu NPs evenly distributed and anchored in the three-dimensional (3-D) nanofiber network of BC through physical bonding. Traces of Cu2O were observed on the membranes probably because the Cu2+ was incompletely reduced. The Cu NPs loaded BC membranes showed efficient long-term antibacterial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) even after immersion in deionized water for up to 90 days. The composite membranes kept sustained release of copper ion, which may contribute to the long-term antibacterial activity. Furthermore, with controlled Cu concentration, BC/Cu membranes did not show obvious cytotoxicity to normal human dermal fibroblasts (NHDF). In all, the present results reveal that BC/Cu membranes with efficient antibacterial activity are promising to be used as wound dressings.

A Novel Antibacterial Membrane Electrode Based on Bacterial Cellulose/Polyaniline/AgNO3 Composite for Bio-Potential Signal Monitoring.

We propose a flexible, dry, and antibacterial electrode with a low and stable skin electrode contact impedance for bio-potential signal monitoring. We fabricated a bacterial cellulose/polyaniline/AgNO3 nanocomposite membrane (BC/PANI/AgNO3) and used it for bio-potential signal monitoring. The bacterial cellulose (BC) provides a 3-D nanoporous network structure, and it was used as a substrate material in the BC/PANI/AgNO3 nanocomposite membrane. Polyaniline (PANI) and AgNO3, acting as conductive and antibacterial components, respectively, were polymerized and deposited on the surfaces of BC nanofibers to produce uniform thin film membrane with flexible, antibacterial, and conductive properties. Various measurements were conducted, in terms of antibacterial activity, skin electrode contact impedance, and qualitative analysis of ECG signal recordings. The BC/PANI/AgNO3 membrane revealed 100% antibacterial activities against both the Staphylococcus aureus and Escherichia coli bacteria. The skin electrode contact impedance of the proposed BC/PANI/AgNO3 electrode is lower than that of the Ag/AgCl gel electrode, with the same active area. In addition, the electrocardiogram (ECG) signals acquired with the proposed electrodes have stable characteristic waveforms, and they are not contaminated by noise. The waveform fidelity of the BC/PANI/AgNO3 membrane electrodes over 800 ECG cardiac cycles is 99.49%, and after the electrodes were worn for 24 hours, a fidelity of 98.40% was recorded over the same number of cardiac cycles. With the low and stable skin electrode contact impedance, the proposed dry BC/PANI/AgNO3 membrane electrode provided high fidelity for ECG signal recordings, thus offering a potential approach for bio-potential signal monitoring. With the above benefits, the novel flexible and dry BC/PANI/AgNO3 electrode has a significant antibacterial. Most of all, it is the first research to develop antibacterial in the electrode design.

Gd-EOB-DTPA DCE-MRI biomarkers in a rabbit model of liver fibrosis.

The purpose of this study was to investigate the correlations between Gd-EOB-DTPA DCE-MRI biomarkers and histopathologic biomarkers of liver fibrosis progression in a rabbit model of liver fibrosis. Thirty-Six New Zealand white rabbits were randomly divided into control (n = 6) and liver fibrosis group (n = 30). Each rabbit in the liver fibrosis group received a weekly subcutaneous injection in the back comprising 50% carbon tetrachloride (CCl4) in oily solution. Control rabbits received subcutaneous injections with the same amount of normal saline solution instead. MR imaging was performed in control and fibrotic rabbits were conducted by MRI at week 0 (n = 36). The fibrotic rabbits were performed MR imaging on 6 weeks, 9 weeks, and 12 weeks after modeling of fibrosis. Before each MRI, peripheral blood was collected, and several biochemical testes are performed. The thirty-four rabbits completed this study. They were then divided into three subgroups according to fibrotic stage: no fibrosis (F0, n = 12), mild fibrosis (F1+F2, n = 14), and advanced fibrosis (F3+F4, n = 8). DCE-MRI measurements show increasing Ktrans and Ve while decreasing iACU90 with increasing fibrosis stage. The significant correlations were observed between mean Ktrans, Ve, iACU90 and percentage of the animal with mild liver fibrosis. For blood biomarkers, there were significant differences between F0 and F1+F2, and between F0 and F3+F4 in the serum levels of ALT (all P < 0.05), and TB (F0 vs. F1+F2, P = 0.004), while no differences were found between F1+F2 group and F3+F4 group (all P > 0.05). There were significant differences between F0 and F1+F2 (P = 0.02). Gd-EOB-DTPA DCE-MRI is a promising method for the noninvasive diagnosis and staging of liver fibrosis. Future studies to evaluate the effectiveness of these techniques in patients with liver fibrosis are warranted.

Novel Electronic-Ionic Hybrid Conductive Composites for Multifunctional Flexible Bioelectrode Based on in Situ Synthesis of Poly(dopamine) on Bacterial Cellulose.

With the rapid development of the wearable detector and medical devices, flexible biosensing materials have received more and more attention. In this work, a novel flexible and conductive biocompatible composite with electronic and ionic bioconductive ability was demonstrated to fabricate a new flexible bioelectrode used for electrophysiological signal detection. This composite was prepared by the in situ self-polymerization of dopamine on the nanofiber of bacterial cellulose (BC) under the neutral pH condition. By using this method, poly(dopamine) (PDA) could form a uniform and continuous wrapped layer on the BC nanofiber that can prevent the aggregation of PDA caused by rapid polymerization under the conventional alkaline condition. In addition, a fabricated film with a special structure is suitable for the transportation of electrons and ions existing in it. Moreover, the flexible conductive film (FCF) reveals an extremely tensile strength, which is 2 times higher than the pure BC in addition to a high electric conductivity, which reaches a value of 10-3 S/cm with a high PDA content. Furthermore, the result of electrocardiogram signal testing shows that the antibacterial property of the FCF bioelectrode has an excellent stability, which is comparable to or better than the commercially available electrode. The BC/PDA-FCF provides a platform for the creation of flexible conductive biomaterials for wearable response devices.

Effects of silica-gentamicin nanohybrids on osteogenic differentiation of human osteoblast-like SaOS-2 cells.

INTRODUCTION: In recent years, there has been an increasing interest in silica (SiO2) nanoparticles (NPs) as drug delivery systems. This interest is mainly attributed to the ease of their surface functionalization for drug loading. In orthopedic applications, gentamicin-loaded SiO2 NPs (nanohybrids) are frequently utilized for their prolonged antibacterial effects. Therefore, the possible adverse effects of SiO2-gentamicin nanohybrids on osteogenesis of bone-related cells should be thoroughly investigated to ensure safe applications. MATERIALS AND METHODS: The effects of SiO2-gentamicin nanohybrids on the cell viability and osteogenic differentiation of human osteoblast-like SaOS-2 cells were investigated, together with native SiO2 NPs and free gentamicin. RESULTS: The results of Cell Count Kit-8 (CCK-8) assay show that both SiO2-gentamicin nanohybrids and native SiO2 NPs reduce cell viability of SaOS-2 cells in a dose-dependent manner. Regarding osteogenesis, SiO2-gentamicin nanohybrids and native SiO2 NPs at the concentration range of 31.25-125 µg/mL do not influence the osteogenic differentiation capacity of SaOS-2 cells. At a high concentration (250 µg/mL), both materials induce a lower expression of alkaline phosphatase (ALP) but an enhanced mineralization. Free gentamicin at concentrations of 6.26 and 9.65 µg/mL does not significantly influence the cell viability and osteogenic differentiation capacity of SaOS-2 cells. CONCLUSIONS: The results of this study suggest that both SiO2-gentamicin nanohybrids and SiO2 NPs show cytotoxic effects to SaOS-2 cells. Further investigation on the effects of SiO2-gentamicin nanohybrids on the behaviors of stem cells or other regular osteoblasts should be conducted to make a full evaluation of the safety of SiO2-gentamicin nanohybrids in orthopedic applications.

Mussel-Inspired General Interface Modification Method and Its Application in Polymer Reinforcement and as a Flame Retardant.

Inspired by the remarkable adhesion of mussels, the mimicking of natural adhesive molecules has been widely used for surface modification. In the present study, an economical and easily available biomimic material named as tannic acid-Fe3+ (TA-Fe3+) was first directly used as a surface modifier, carbonization agent, smoke inhibitor, and flame-retardant synergist. Compared with the flame-retardant magnesium hydroxide (Mg(OH)2), TA-Fe3+-modified Mg(OH)2 endowed polyamide 6 (PA 6) with improved mechanical performance and flame-retardant properties. The flame-retardant and smoke-suppressant properties were tested by the limiting oxygen index and cone calorimeter tests. The flame-retardation mechanism was investigated by thermogravimetric analysis, scanning electron microscopy, and X-ray photoelectron spectroscopy. The tensile strength could increase up to 90%, and the modified flame retardant was found to have higher UL-94 grade with the same dosage of flame-retardant additives. The peak heat release rate, total heat release, peak of smoke production rate, and total smoke production were significantly reduced. The synergistic effect between TA-Fe3+ and Mg(OH)2 was also discussed. This study provides new insights into the direct utilization of a biomimicking adhesive molecule, TA-Fe3+, to realize simultaneous composite reinforcement and flame-retardant property enhancement. Meanwhile, because of the extensive synergies of flame-retardant metal oxide with iron element and the universal growth characteristics of TA-Fe3+, it has potential applications in the preparation of various flame-retardant polymers.

Constitutive overexpression of multiple cytochrome P450 genes associated with pyrethroid resistance in Helicoverpa armigera.

Our previous studies showed that enhanced cytochrome P450-mediated detoxification is a major mechanism responsible for pyrethroid resistance in a laboratory-selected strain (YGF) of Helicoverpa armigera (Hübner). Two new cytochrome P450 genes, CYP9A12 and CYP9A14 (encoding 531 and 530 amino acid residues, respectively) were isolated from the fat body of the YGF strain of H. armigera. The mRNA expression levels of these two CYP9 P450 genes, together with CYP6B7 and CYP4G8 (previously reported to be overexpressed in pyrethroid-resistant strains), were assessed by real-time quantitative reverse transcription-polymerase chain reaction in the final instars of a field-derived YG strain (with seven-fold resistance to the pyrethroid fenvalerate) and the YGF strain (selected from the YG strain with fenvalerate in the laboratory, with 1,690-fold resistance to fenvalerate). The mRNA expression levels of CYP9A12, CYP9A14, and CYP6B7 in the fat body of the YGF strain increased to 433-, 59-, and 9.3-fold, respectively, compared with the YG strain, whereas no overexpression was revealed for CYP4G8. CYP9A12 and CYP9A14 had 19- and 4.3-fold overexpression in the midgut of the YGF strain compared with the YG strain, respectively, but CYP6B7 and CYP4G8 were not overexpressed. The current study provided evidence that constitutive overexpression of multiple cytochrome P450 genes (CYP9A12, CYP9A14, and CYP6B7) is associated with pyrethroid resistance in H. armigera.