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Autoimmune hepatitis (AIH) is a typical T cell-mediated chronic liver disease with a higher incidence in females. However, the molecular mechanism for the female predisposition is poorly understood. Estrogen sulfotransferase (Est) is a conjugating enzyme best known for its function in sulfonating and deactivating estrogens. The goal of this study is to investigate whether and how Est plays a role in the higher incidence of AIH in females. Concanavalin A (ConA) was used to induce T cell-mediated hepatitis in female mice. We first showed that Est was highly induced in the liver of ConA-treated mice. Systemic or hepatocyte-specific ablation of Est, or pharmacological inhibition of Est, protected female mice from ConAinduced hepatitis regardless of ovariectomy, suggesting the effect of Est inhibition was estrogen independent. In contrast, we found that hepatocyte-specific transgenic reconstitution of Est in the whole-body Est knockout (EstKO) mice abolished the protective phenotype. Upon the ConA challenge, EstKO mice exhibited a more robust inflammatory response with elevated production of proinflammatory cytokines and changed liver infiltration of immune cells. Mechanistically, we determined that ablation of Est led to the hepatic induction of lipocalin 2 (Lcn2), whereas ablation of Lcn2 abolished the protective phenotype of EstKO females. Our findings demonstrate that hepatocyte Est is required for the sensitivity of female mice to ConA-induced and T cell-mediated hepatitis in an estrogenindependent manner. Est ablation may have protected female mice from ConA-induced hepatitis by upregulating Lcn2. Pharmacological inhibition of Est might be a potential strategy for the treatment of AIH. [ABSTRACT FROM AUTHOR]

Recent years have witnessed the emergence of worldwide megalopolises and the accompanying public safety events, making urban safety a top priority in modern urban management. Among various threats, dangerous goods such as gas and hazardous chemicals transported through cities have bred repeated tragedies and become the deadly "bomb" we sleep with every day. While tremendous research efforts have been devoted to dealing with dangerous goods transportation (DGT) issues, further study is still in great need to quantify this problem and explore its intrinsic dynamics from a big data perspective. In this article, we present a novel system called DGeye, to feature a fusion between DGT trajectory data and residential population data for dangers perception and prediction. Specifically, DGeye first develops a probabilistic graphical model-based approach to mine spatio-temporally adjacent risk patterns from population-aware risk trajectories. Then, DGeye builds the novel causality network among risk patterns for risk pain-point identification, risk source attribution, and online risky state prediction. Experiments on both Beijing and Tianjin cities demonstrate the effectiveness of DGeye in real-life DGT risk management. As a case in point, our report powered by DGeye successfully drove the government to lay down gas pipelines for the famous Guijie food street in Beijing. [ABSTRACT FROM AUTHOR]

To study the spatial variability of water surface fluxes, turbulence measurements on a moving platform are useful. However, such measurements have only been carried out with large research vessels over the ocean. We tested the feasibility of flux measurements with a small excursion ship over Lake Kasumigaura, the second largest lake in Japan. After the formal application of coordinate rotations to account for the ship's movements, we derived mean wind velocities as well as latent and sensible heat fluxes. They were compared with spatially interpolated wind velocities from meteorological stations and with fluxes estimated from the bulk method. Equally good agreements were found with those reported in previous studies over the ocean, indicating the feasibility of ship measurements in a lake. Possible error sources were identified for the improvement of the accuracy of flux estimation. [ABSTRACT FROM AUTHOR]

The freeze-thaw changes of seasonally frozen ground (SFG) are an important indicator of climate change. Based on observed daily freeze depth of SFG from meteorological stations on the Tibetan Plateau (TP) from 1960 to 2014, the spatial-temporal characteristics and trends in SFG were analyzed, and the relationships between them and climatic and geographical factors were explored. Freeze-thaw changes of SFG on a regional scale were assessed by multiple regression functions. Results showed multiyear mean maximum freeze depth, freeze-thaw duration, freeze start date, and thaw end date that demonstrate obvious distribution characteristics of climatic zones. A decreasing trend in maximum freeze depth and freeze-thaw duration occurred on the TP from 1960 to 2014. The freeze start date has been later, and the thaw end date has been significantly earlier. The freeze-thaw changes of SFG significantly affected by soil hydrothermal conditions on the TP could be assessed by elevation and latitude or by air temperature and precipitation, due to their high correlations. The regional average of maximumfreeze depth and freeze-thaw duration caused by climatic and geographical factors were larger than those averaged using meteorological station data because most stations are located at lower altitudes. Maximum freeze depth and freeze-thaw duration have decreased sharply since 2000 on the entire TP. Warming and wetting conditions of the soil resulted in a significant decrease in maximum freeze depth and freeze-thaw duration in the most area of the TP, while drying soil results in a slight increase of them in the southeast of the TP. [ABSTRACT FROM AUTHOR]

Background: Cefixime is a third-generation oral cephalosporin antibiotic widely used to treat bacterial infections. Typical methods for cefixime analysis use expensive instruments or sophisticated experimental procedures, and thus a sensitive and practical method is urgently needed for cefixime detection and analysis. Objective: To develop a sensitive and robust cefixime “switch-on” sensor based on carbon quantum dots (CQDs). Methods: In this study, black soya beans were used as an inexpensive carbon source for a “green” synthesis of fluorescent black soya bean (BS)-carbon quantum dots (CQDs). The fluorescence of these particles could be efficiently quenched by Ce(IV)due to the ground state recombination and electron transfer (ET) between Ce(IV)and BS-CQDs. In the presence of cefixime, the ET was interrupted and the fluorescent signal was recovered. Results/Conclusions: This method showed high sensitivity and an impressively low detection limit of 169 nM. Highlights: This low-cost, simple strategy for cefixime detection exhibits excellent stability, selectivity, and sensitivity. Moreover, it was successfully applied for the detection of cefixime in tablets and in a complex biological environment, confirming its great potential utility for drug analysis, biological process research, and clinical research. [ABSTRACT FROM AUTHOR]

To improve the probability and stability of breakdown discharge in a three-electrode spark-gap switch for a high-power transversely excited atmospheric CO2 laser and to improve the efficiency of its trigger system, we developed a high-voltage pulse trigger generator based on a two-transistor forward converter topology and a multiple-narrow-pulse trigger method. Our design uses a narrow high-voltage pulse (10 μs) to break down the hyperbaric gas between electrodes of the spark-gap switch; a dry high-voltage transformer is used as a booster; and a sampling and feedback control circuit (mainly consisting of a SG3525 and a CD4098) is designed to monitor the spark-gap switch and control the frequency and the number of output pulses. Our experimental results show that this pulse trigger generator could output high-voltage pulses (number is adjusted) with an amplitude of >38 kV and a width of 10 μs. Compared to a conventional trigger system, our design had a breakdown probability increased by 2.7%, an input power reduced by 1.5 kW, an efficiency increased by 0.12, and a loss reduced by 1.512 kW. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (H2S) is known to play a physiological role in processes as diverse as vasodilation, maintenance of vascular tone, neuro- transmission, and immune response. The multitude of physiological functions in which H2S is involved warrants the development of useful methods for its detection. Here, we introduce a simple and continuous H2S detection method that exploits the relatively high polydimethylsiloxane (PDMS) permeability of H2S in comparison to other thiols typically encountered in the cellular milieu. In this method, 96-well inserts constructed of PDMS act as an H2S-permeable membrane, eliminating nonspecific thiol detection. This design also makes it possible to use virtually any available thiol-specilic probe such as Ellman's reagent which was used here to detect H2S once it crossed the PDMS membrane. Utilizing this method, a detection limit of 9.2 ± 1.9 ppb(m) (parts per billion (by mole) or ∼0.51 μM in 1.6 mL of buffer) free H2S (detected as solution sulfide) was achieved. In addition, the assay was used to determine KM and Vmax for natural substrates of cystathionine γ-lyase (CSE), the main enzyme responsible for H2S production in peripheral tissues. The KM and Vmax of CSE for cysteine were 3.79 ± 2.07 mM and 0.37 ± 0.02 nmol H2S/min, respectively. KM and Vmax for homocysteine were 6.90 ± 1.78 mM and 1.10 ± 0.19 nmol H2S/min, respectively. In addition, the assay was used to examine the potential for a direct interaction of H2S and NO. The levels of detected H2S decreased in the presence of NO under normoxia but not under anoxia indicating that H2S does not react with NO but with N2O3 likely formed in the hydrophobic environment of PDMS. [ABSTRACT FROM AUTHOR]

Objective: Metabolic syndrome (MetS) is closely related to the increased risk and poor prognosis of endometrial cancer (EC). The purpose of this study was to analyze the relationship between metabolic risk score (MRS) and EC, and establish a predictive model to predict the prognosis of EC. Methods: A retrospective study was designed of 834 patients admitted between January 2004 to December 2019. Univariate and multivariate Cox analysis were performed to screen independent prognostic factors for overall survival (OS). A predictive nomogram is built based on independent risk factors for OS. Consistency index (C-index), calibration plots and receiver operating characteristic curve were used to evaluate the predictive accuracy of the nomogram. Results: The patients were randomly divided into training cohort (n=556) and validation cohort (n=278). The MRS of EC patients, ranging from -8 to 15, was calculated. Univariate and multivariate Cox analysis indicated that age, MRS, FIGO stage, and tumor grade were independent risk factors for OS (p<0.05). The Kaplan-Meier analysis demonstrated that EC patients with low score showed a better prognosis in OS. Then, a nomogram was established and validated based on the above four variables. The C-index of nomogram were 0.819 and 0.829 in the training and validation cohorts, respectively. Patients with high-risk score had a worse OS according to the nomogram. Conclusion: We constructed and validated a prognostic model based on MRS and clinical prognostic factors to predict the OS of EC patients accurately, which may help clinicians personalize prognostic assessments and effective clinical decisions. [ABSTRACT FROM AUTHOR]

The existing moving box mechanism pot seedling transplanting machine on the market moves too fast when the picked seedling is collected, which negatively impacts the seedling picking performance. In order to improve the performance, two types of variable speed continuous moving box schemes were designed in this study. The first scheme was to apply a spiral-gear moving box spiral shaft with sine curve characteristics in the box moving mechanism, whereas the second one was to change the circular gear in the moving box into an elliptical gear with a speed shifting transmission mechanism. The working mechanism of the mechanical structure was analyzed, and the kinematic model was established. A dynamic analysis of the slider mechanism was performed. A virtual prototype was established according to agronomic parameters, and the virtual prototype experiments were conducted in ADAMS. The physical prototype and the high-speed photography experiment were performed on the test bench of a transplanting machine frame. The theoretical analysis, virtual prototype and physical prototype test results were consistent, which verified the validity of the theoretical model, virtual prototype and physical prototype and ensured the feasibility of the system. [ABSTRACT FROM AUTHOR]

To characterize complex and heterogeneous side information in recommender systems, the heterogeneous information network (HIN) has shown superior performance and attracted much research attention. In HIN, the rich entities, relations, and paths can be utilized to model the correlations of users and items; such a task setting is often called HIN-based recommendation. Although HIN provides a general approach to modeling rich side information, it lacks special consideration on the goal of the recommendation task. The aggregated context from the heterogeneous graph is likely to incorporate irrelevant information, and the learned representations are not specifically optimized according to the recommendation task. Therefore, there is a need to rethink how to leverage the useful information from HIN to accomplish the recommendation task. To address the above issues, we propose a Curriculum pre-training based HEterogeneous Subgraph Transformer (called CHEST) with new data characterization, representation model, and learning algorithm. Specifically, we consider extracting useful information from HIN to compose the interaction-specific heterogeneous subgraph, containing highly relevant context information for recommendation. Then, we capture the rich semantics (e.g., graph structure and path semantics) within the subgraph via a heterogeneous subgraph Transformer, where we encode the subgraph into multi-slot sequence representations. Besides, we design a curriculum pre-training strategy to provide an elementary-to-advanced learning process. The elementary course focuses on capturing local context information within the subgraph, and the advanced course aims to learn global context information. In this way, we gradually capture useful semantic information from HIN for modeling user-item interactions. Extensive experiments conducted on four real-world datasets demonstrate the superiority of our proposed method over a number of competitive baselines, especially when only limited training data is available. [ABSTRACT FROM AUTHOR]

Objective: This study aims to analyze factors associated with lymphovascular space invasion (LVSI) and evaluate the prognostic significance of LVSI in Chinese endometrioid endometrial cancer (EEC) patients. Methods: Five-hundred eighty-four EEC patients undergoing surgery in our center from 2006 to 2016 were selected for analysis. Univariate analysis and multivariate logistic regression were used to examine relevant factors of LVSI. To evaluate the prognostic role of LVSI, survival analyses were conducted. In survival analyses, both multivariate Cox regression and propensity score matching were used to control the confounders. Results: The incidence of LVSI was 12.16% (71/584). Diabetes history (p=0.021), lymph node metastasis (p=0.005), deep myometrial invasion (p<0.001) and negative PR expression (p=0.007) were independently associated with LVSI. Both Kaplan-Meier method and univariate Cox regressions showed LVSI negative and positive cases had similar tumorspecific survival (TSS) and disease-free survival (DFS). After adjusting for the influence of adjuvant therapy and other clinicopathological factors with multivariate Cox regressions, LVSI still could not bring additional survival risk to the patients (p=0.280 and p=0.650 for TSS and DFS, respectively). This result was verified by Kaplan-Meier survival analyses after propensity score matching (p=0.234 and p=0.765 for TSS and DFS, respectively). Conclusion: LVSI does not significantly compromise the survival outcome of Chinese EEC patients. [ABSTRACT FROM AUTHOR]

Steel arches are widely used to construct main arches in modern concrete bridges. However, the applicability of existing steel arches has certain limitations. To expand the application scope of steel arches and enhance the material utilization rate, this study proposed a calculation and analysis model for a novel steel arch with an adjustable axis. First, the finite element calculation model of the arch structure was established using the finite element software Midas Civil based on Timoshenko beam theory. Second, the sensitive factors that affect the mechanical response characteristics of the novel arch, such as the connection method of the upper chord in the arch section, boundary conditions of the arch springing hinge, and temperature, were thoroughly discussed through calculation and analysis of engineering projects. Finally, the effect of span and width on the arch stability was discussed using the linear elastic analysis method. The mechanical response of the new steel arch was obtained, and the reliability of the calculation results was verified. Results demonstrate that a rigid connection is applicable to the upper chord connection of the arch section, and the two-hinged arch applies to the frame. Temperature changes can lead to obvious deformation and the decrease in temperature indicates a clear stress on the arch. Without considering wind load, the minimum wide-span ratio for the novel arch reaches 1:20. This study can provide a reference for application and calculation analysis of such arches. [ABSTRACT FROM AUTHOR]

By utilizing the modified strain energy function from Gao, uniaxial tension and biaxial tension of rubber like materials has been researched. For verification purposes, the proposed constitutive model from Gao has been implemented in a general-purpose FEA software. And then the nonlinear finite element procedure is presented for the analysis of rubber-like materials. The volumetric incompressibility condition of the deformation from rubber like materials is included in the formulation by using the penalty method. By utilizing the FEA software ABAQUS, uniaxial tension and biaxial tension model from rubber like materials have been established. In order to compare the FEA results with theoretical results, curve stress-principal stretch has been plotted with different material parameters, which indicate the correctness and rationality of theoretical analysis. In the end, analysis of cylindrical rubber membrane has been proposed based on the proposed strain energy function. The results show that the constitutive parameter n has a strengthening effect on the rubber membrane material and instability of cylindrical rubber membrane will be occur as the circumferential or longitudinal principal stretch increases. This research has revealed the deformational mechanism and provided reasonable reference for the design of rubber like materials. [ABSTRACT FROM AUTHOR]

Background: We investigated antitumor activity and underlying mechanisms of DNA topoisomerase I (TopI) inhibitor gimatecan and irinotecan in gastric cancer (GC) in vitro cell lines and in vivo patient-derived xenograft (PDX) models.Methods: GC cell lines SNU-1, HGC27, MGC803 and NCI-N87 were used to evaluate cell viability and apoptosis after gimatecan or irinotecan treatment, using a cell proliferation assay and flow cytometry, respectively. DNA TopI expression and critical molecules of PI3K/AKT, MAPK and apoptosis signaling pathways were analyzed with western blot. For in vivo studies, five PDXs models were treated with gimatecan or irinotecan to assess its antitumor activity. Immunohistochemistry staining of Ki-67 was performed after mice were sacrificed.Results: Gimatecan inhibited the proliferation of GC cells in vitro in a dose- and time-dependent manner by inducing apoptosis, and gimatecan had greater inhibitory effects than irinotecan. In addition, both gimatecan and irinotecan demonstrated significant tumor growth inhibition in in vivo PDX models. Gimatecan treatment significantly inhibited the expression of DNA TopI, phosphorylated AKT (pAKT), phosphorylated MEK (pMEK) and phosphorylated ERK (pERK). Meanwhile, gimatecan could also activate the JNK2 and p38 MAPK pathway as indicated by upregulation of phosphorylated p38 MAPK (p-p38) and phosphorylated JNK2 (pJNK2).Conclusions: For the first time, we have shown that the antitumor activity of gimatecan in GC via suppressing AKT and ERK pathway and activating JNK2 and p38 MAPK pathway, which indicated that gimatecan might be an alternative to irinotecan in the treatment of GC. [ABSTRACT FROM AUTHOR]

Although it is well known that the performances of two-dimensional transition metal dichalcogenide (2D-TMD) based devices are strongly affected by humidity, the roles of water molecules in the electronic properties of 2D-TMDs are still unclear. In this work, the influence of water molecules on the electrical properties of monolayer molybdenum disulfide (MoS2) is studied systemically using the dielectric force microscopy (DFM) technique. Taking the advantage of the DFM technique and other nondestructive characterization techniques, the electronic properties (surface potential, dielectrics, and carrier mobility) of atomically thin MoS2 exposed to different levels of humidity are investigated. Furthermore, Raman spectroscopy manifested the correlation between the optical phonon and the mobility drop of MoS2 flakes when subjected to humidity variations. Our results provide an in-depth understanding of the mechanism of water molecules interacting with MoS2. [ABSTRACT FROM AUTHOR]

Background: Cell cycle dysregulation is common in human malignancies, and CDK4/6 inhibitors targeting cell cycle have potential antitumor activity. SHR6390 is a novel small molecule inhibitor specifically targeting the CDK4/6 pathway. However, the role of SHR6390 in esophageal squamous cell carcinoma (ESCC) remains unknown, which will be investigated in our study.Methods: Eca 109, Eca 9706, and KYSE-510 ESCC cell lines were chosen for further analysis. The effect of SHR6390 on cell viability, cell cycle and cell apoptosis, the status of kinases in Cyclin D1-CDK4/6-Rb pathway were determined by MTS assay, flow cytometry, and western blotting, respectively. Cell-derived and patient-derived xenografts were established to investigate the effects of drugs in vivo.Results: SHR6390 could suppress cell proliferation in vitro cell lines and inhibit tumor growth in vivo PDX models with different drug susceptibility. The effective treatment of SHR6390 induced the inhibition of phosphorylated Rb and cell cycle arrest at G1 phase both in cell lines and in xenografts. SHR6390 combined with paclitaxel or cisplatin offered synergistic inhibitory effects in cell-derived xenografts especially in Eca 9706 xenografts which showed relative lower sensitivity of SHR6390 single. Moreover, low expression of CDK6 and/or high expression of Cyclin D1 might be associated with high sensitivity of SHR6390, which would be validated in the future.Conclusions: CDK4/6 inhibitor-SHR6390 exerted potential antitumor activity against ESCC cell lines and xenografts, and evaluation of CDK6 and Cyclin D1 expressions might be helpful to select patients beneficial from SHR6390, which provided evidences for future clinical trials. [ABSTRACT FROM AUTHOR]

Background: Human Cytomegalovirus (HCMV) infections can be found throughout the body, especially in epithelial tissue. Animal model was established by inoculation of HCMV (strain AD-169) or coinoculation with Hepatitis E virus (HEV) into the ligated sacculus rotundus and vermiform appendix in living rabbits. The specimens were collected from animals sacrificed 1 and a half hours after infection. Results: The virus was found to be capable of reproducing in these specimens through RT-PCR and Western-blot. Severe inflammation damage was found in HCMV-infected tissue. The viral protein could be detected in high amounts in the mucosal epithelium and lamina propria by immunohistochemistry and immunofluorescense. Moreover, there are strong positive signals in lymphocytes, macrophages, and lymphoid follicles. Quantitative statistics indicate that lymphocytes among epithlium cells increased significantly in viral infection groups. Conclusions: The results showed that HCMV or HEV + HCMV can efficiently infect in rabbits by vivo ligated intestine loop inoculation. The present study successfully developed an infective model in vivo rabbit ligated intestinal Loop for HCMV pathogenesis study. This rabbit model can be helpful for understanding modulation of the gut immune system with HCMV infection. [ABSTRACT FROM AUTHOR]

Artocarpus heterophyllus, a popular tropical fruit commonly known as the jackfruit tree, is normally planted in subtropical or tropical areas. Since a variety of phytochemicals isolated from A. heterophyllus have been found to possess potently anti-inflammatory, antiviral and antimalarial activities, researchers have devoted much interest to its potential pharmaceutical value. However, the exact mechanism underlying its anti-inflammatory activity is not well characterized. In this study, seven natural products isolated from A. heterophyllus, including 25-Hydroxycycloart-23-en-3-one (HY), Artocarpin (AR), Dadahol A (DA), Morachalcone A (MA), Artoheterophyllin B (AB), Cycloheterophyllin (CY) and Moracin C (MC) were collected. Lipopolysaccharide (LPS)-stimulated inflammatory response in RAW264.7 macrophages were used in this study. Among these compounds, MC significantly inhibited LPS-activated reactive oxygen species (ROS) and nitric oxide (NO) release without marked cytotoxicity. Furthermore,MC effectively reduced LPS stimulated up-regulation of mRNA and protein expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and serval pro-inflammatory cytokines (interleukin-1 (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor α (TNF-α)). Mechanistic studies revealed that the anti-inflammatory effect of MC was associated with the activation of the mitogen activated protein kinases (MAPKs) (including p38, ERK and JNK) and nuclear factor-κB (NF-κB) pathways, especially reducing the nuclear translocation of NF-κB p65 subunit as revealed by nuclear separation experiment and confocal microscopy. [ABSTRACT FROM AUTHOR]

Diabetes is a significant public health problem that can be treated with insulin therapy; however, therapies designed to cure diabetes are limited. The goal of the current study was to assess the potential for curative treatment of diabetes using adipose-derived stem cells (ADSCs). To achieve this goal, the differentiation of rat ADSCs into pancreatic islet-like cells induced by coculture with pancreatic adult stem cells (PASCs) was characterized. Differentiation of ADSCs into islet-like cells induced by coculturing was determined morphologically, as well as by the assessment of islet cell markers using dithizone staining, immunohistochemistry, RT-PCR, qPCR, and western blotting. The results showed that ADSCs formed islet-like round cell masses after coculture with PASCs. These differentiated cells were shown to be positive for islet cell markers, including dithizone incorporation; PDX1, CK19 and Nestin by immunohistochemistry, and insulin, PDX1 and glucagon expression by RT-PCR. Differentiated ADSCs induced by coculturing also expressed insulin at the mRNA and protein level, with the level of insulin mRNA expression in cocultured ADSCs being 0.05 times greater than that of PASCs ( P < 0.05). Taken together, our results demonstrate that ADSCs can be induced to differentiate into islet-like cells by coculture with PASCs; thus these cells can be used for transplantation, providing a theoretical foundation for the treatment of diabetes using this approach. [ABSTRACT FROM AUTHOR]

This study developed an exciting alternative to the polymeric delivery system in cancer therapy. In this study, novel organic-inorganic hybrid polymeric micelles based on chitosan were synthesized and found to be robust nanocarriers for intracellular controlled release drug delivery. The polymeric micelles of carboxymethyl chitosan-grafted-p(ethylene glycol)-dodecylamine (CMC-g-PEG-DDA) were readily mineralized in the presence of calcium chloride (CaCl2) and disodium hydrogen phosphate (Na2HPO4). Mineralization reduced polymeric micelles' size from 239 nm to 138 nm and formed a multi-core structure. The mineralized polymeric micelles (MPM) exhibited enhanced serum stability. The DOX release from the DOX-loaded mineralized polymeric micelles (MPM@DOX) at physiological pH was efficiently inhibited, At an endosomal pH (pH 5.0), DOX release was facilitated due to rapid dissolution of the calcium phosphate (CaP). These results indicate that mineralized polymeric micelles are potentially as robust carriers that can release DOX at specific sites under mild acidic conditions, such as in an extracellular matrix of tumor tissue and intracellular cell compartments. [ABSTRACT FROM AUTHOR]

The fiber Bragg grating has been widely used in sensors. We have studied the spectral properties of uniform Bragg gratings in photonic crystal fibers under transverse pressure. By the finite element method, the relation between the birefringence and the pressure was simulated in bare photonic crystal fibers. The results show that the birefringence is changed even under weak pressure. A new method based on polarization-dependent loss is presented for measuring pressure. The maximal amplitude of the polarization-dependent loss varies linearly in the pressure range of 0 to 4 MPawith a slope of 0.75 MPa−1. [ABSTRACT FROM AUTHOR]

The direct synthesis of a millimeter-sized core–shell-like catalyst that can be used in the hydrogenation of carbon dioxide to dimethyl ether was achieved by in situ hydrothermal synthesis. The capsule catalyst exhibited a special core–shell-like structure of a coprecipitated CuO/ZnO/Al2O3core enwrapped by one layer of metal-doped amorphous silica–alumina (ASA) membrane and was characterized by XRD, SEM, and thermal analysis. The effects of metal oxide cores and membranes prepared with different precipitants, structure-directing templates, and hydrothermal synthesis conditions, as well as temperatures and pressures, on the catalytic activity of the capsule catalyst for the hydrogenation of CO2to dimethyl ether were investigated. Under reaction conditions of a pressure of 3.0 MPa, a space velocity (SV) of 1800 mL·gcat–1·h–1, a CO2/H2volume ratio of 1:3, and a temperature of 266 °C, the capsule catalysts with cores coprecipitated by urea using n-butylamine as the templating agent to enwrap the amorphous silica–alumina membranes had excellent catalytic properties for dimethyl ether synthesis, and the conversion of CO2reached 47.1%, with a dimethyl ether yield and selectivity of 19.9% and 42.4%, respectively. [ABSTRACT FROM AUTHOR]

Abstract  Y-shaped diblock copolymer polycaprolactone-block-(polystyrene)2 [PCL-b-(PSt)2] was synthesized successfully by the combination of enzymatic ring-opening polymerization (eROP) and atom transfer radical polymerization (ATRP). CH3O-terminated PCL was synthesized firstly by eROP of ε-caprolactone (ε-CL) in the presence of biocatalyst Novozyme 435 and initiator CH3OH, subsequently the resulting PCL was converted to macroinitiator by the esterification of it with 2,2-dichloro acetyl chloride (DCAC). PCL-b-(PSt)2 diblock copolymers were synthesized in an ATRP of the styrene with CuCl/2,2′-bipyridine as the catalyst system. The kinetic analysis of ATRP indicated a controlled/‘living’ radical polymerization. The structure and composition of obtained polymers were characterized with NMR, GPC and FTIR. The thermal behavior was characterized by differential scanning calorimetry (DSC). [ABSTRACT FROM AUTHOR]

Abstract  The synthesis of well-defined H-shaped block copolymer based on the enzymatic ring-opening polymerization (eROP) and atom transfer radical polymerization (ATRP) is described. The dihydroxyl polycaprolactone (PCL) was synthesized by the eROP of ε-caprolactone (ε-CL) in the presence biocatalyst Novozyme 435 and initiator ethylene glycol. Subsequently, the resulting PCL was converted to tetrafunctional macroinitiator by the esterification with 2,2-dichloro acetyl chloride (DCAC). The H-shaped block copolymer was then synthesized by the ATRP of styrene. The polymers were characterized by NMR and GPC. Linear first-order kinetics, linearly increasing molecular weight with conversion, and low polydispersities observed from the ATRP of St showed that the polymerization was well controlled. (PSt)2-b-PCL-b-(PSt)2 block copolymers with varying molecular weight and controllable composition were obtained. [ABSTRACT FROM AUTHOR]

A symmetric linear CBABC pentablock copolymer consisting of poly(ethylene oxide) (PEO), polycaprolactone (PCL), and polystyrene (PSt) was synthesized by the combination of enzymatic ring-opening polymerization (eROP) and atom transfer radical polymerization (ATRP). Dihydroxyl-capped PEO first initiated eROP of -CL in the presence of biocatalyst Novozyme 435. Subsequently, the resulting dihydroxyl-terminated copolymer PCL-b-PEO-b-PCL was converted to bromine-ended triblock macroinitiator by the esterification with -bromopropionyl bromide. Pentablock copolymer PSt-b-PCL-b-PEO-b-PCL-b-PSt was obtained via a subsequent ATRP of styrene(St), and its kinetics analysis indicated a “living”/controlled radical polymerization. The self-assembly behavior of pentablock copolymer was investigated in aqueous media. The “crew-cut” aggregates of various morphologies were observed, such as normal spherical micelles, rodlike micelles, vesicles, lamellae, and large compound micelles (LCMs). In addition, it was found that both the copolymer composition and the copolymer concentration in THF had a great influence on the morphologies of the aggregates. [ABSTRACT FROM AUTHOR]

Homopolymer and macromolecule-metal complexes (MMC) brushes on silicon wafers were successfully synthesized by the combination of self-assembly of the monolayer of initiator, atom transfer radical polymerization (ATRP) and coordination to metal ions. The initiator monolayer attached to silicon wafers was prepared by self-assembly of 3-aminopropyltriethoxysilane followed by amidation with α-bromopropionyl bromide, and permitted subsequent surface-initiated ATRP of butyl methacrylate (BMA) and acrylamide (AAM). From atomic force microscope (AFM) images it could be observed that the surface of poly(butyl methacrylate) (PBMA) brushes was uniform, while the surface of polyacrylamide (PAAM) brushes grew a large number of nanoscale protrusions. After coordination to metal ions, Pb2+ and Cd2+, MMC brushes of PAAM were formed, while the nanoprotrusions with different sizes and densities were observed on the surface of MMC brushes. X-ray photoelectron spectroscopy (XPS) was used to determine a molar ratio of 2.80C:1.00O: 0.75N for the PAAM brushes, in good agreement with the value (3.00C:1.00O:1.00N) based on the monomer AAM. Moreover, the occurrence of the new XPS signals of metal ions Pb2+ (139.1 and 143.8 eV) and Cd2+ (405.4 and 412.5 eV) verified the formation of the MMC brushes. [ABSTRACT FROM AUTHOR]

The hyperbranched aliphatic polyester P(ϵ-CL) was synthesized by means of Novozyme435-catalyzed ring-opening polymerization (ROP) of BHB (2, 2-bis(hydroxymethyl) butyric acid). The chains ended with hydroxyl of P(E-CL) were modified by the esterification of ϵ-bromopropionyl bromide to obtain hyperbranched difunctional macroinitiator, which was used in the ATRP of St. CuCl/HMTETA was used as the catalyst system in the reaction of ATRP to acquire the hyperbranched copolymers polystyrene-block-poly(2,2-bis(hydroxymethyl) butyric acid). The copolymer was confirmed by NMR and GPC. [ABSTRACT FROM AUTHOR]