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Objectives: The aims of this study were to assess the vortex characteristics of left ventricle (LV) in fetuses with coarctation of the aorta (CoA) using high–frame rate ultrasound with blood speckle‐tracking (BST) and explore its relationships with cardiac function and morphology parameters. Methods: Thirty fetuses with CoA and 30 gestational‐age matched normal fetuses were included in this cross‐sectional study. The area, length, width, and position of the vortex in the LV were recorded and quantitatively analyzed by BST echocardiography. The associations of vortex properties with ventricular function and morphology were also determined. Results: Based on BST imaging, the LV vortex can be observed in 93% of the fetuses. The fetuses with CoA exhibited significantly larger and wider vortex than the controls (P <.05). Linear regression analysis indicated that vortex area was positively related to sphericity index of LV as well as isovolumic relaxation time (r =.52, P =.003 and r =.42, P =.021). There was a negative correlation between vortex area and mitral valve size (r = −.443, P =.014). No significant association was found between vortex area and myocardial performance index and aortic isthmus size. Conclusions: It is feasible to quantitatively evaluate the left ventricular vortex in fetuses by BST. The fetuses with CoA exhibited greater vortex area and width, and the altered vortex property is associated with geometry of LV. This will facilitate our comprehension of the unique flow patterns and early cardiac remodeling in fetuses with CoA. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the vascular impedance of the pulmonary arteries in fetuses with tetralogy of Fallot (TOF) by Doppler echocardiography. Methods: A total of 42 fetuses with TOF (TOF group) and 84 gestational age‐matched normal fetuses (control group) were prospectively collected from the Second Xiangya Hospital of Central South University from August 2022 to January 2023. The severity of TOF was classified into mild TOF (z score ≥−2), moderate TOF (−4 < z score < −2), or severe TOF (z score ≤−4) according to the z score value of the pulmonary annulus diameter. The pulsatility index (PI) of the main pulmonary artery (MPA), distal left pulmonary artery (DLPA), and distal right pulmonary artery (DRPA) were measured by pulsed‐wave Doppler. The differences in clinical data and echocardiographic parameters between TOF group, control group, and TOF subgroups were compared. Results: Compared with the control group, MPA‐PI increased significantly, whereas DLPA‐PI and DRPA‐PI decreased in TOF group (all P <.001). There were no significant differences in MPA‐PI and DRPA‐PI among mild TOF, moderate TOF, and severe TOF (all P >.05). However, DLPA‐PI decreased significantly in severe TOF compared with mild TOF (P <.05). Conclusion: Fetuses with TOF presented increased vascular impedance in the pulmonary trunk and decreased impedance in distal pulmonary artery branches. Further large and follow‐up studies are needed to demonstrate the associations between those changed vascular impedances and the development of PA in patients with TOF. [ABSTRACT FROM AUTHOR]

Summary The LC filter integrated quasi‐Z source indirect matrix converter (QZS‐IMC) filters the input voltages and currents while highly expanding voltage boost ratio through the combined QZS network, avoiding the additional input filter while maintaining full‐silicon solution. The traditional proportional‐integral (PI) control method of IMC is realized through the PI regulators with pulse width modulation (PWM), which is complicated due to elaborated vectors computation and duty cycle composition of IMC and extra control loops design is mandatory. This paper proposes a model predictive control (MPC) for the LC filter integrated QZS‐IMC. Based on the established discrete models of circuit voltages and currents, the proposed control method measures the present circuit variables and predicts the variables in the next sampling period. Then, a predefined cost function is evaluated with the predictions and references at each active switching states of the IMC. An optimal switching state that ensures the smallest value of the cost function is applied to the power devices at the beginning of next sampling time. Simulation and experiment are carried out to demonstrate effectiveness of the proposed MPC for the LC filter integrated QZS‐IMC. [ABSTRACT FROM AUTHOR]

The defect‐free structure of Mo‐based materials is a "double‐edged sword", which endows the material with excellent stability, but limits its chemical versatility and application in electrochemical hydrogen evolution reaction (HER). Carbon doping engineering is an attractive strategy to effectively improve the performance of Mo‐based catalyst and maintain their stability. Herein, we report a cross‐linked porous carbon‐doped MoO2 (C–MoO2)‐based catalyst Ru/C–MoO2 for electrochemical HER, which is prepared by the convenient redox solid‐phase reaction (SPR) of porous RuO2/Mo2C composite precursor. Theoretical studies reveal that due to the presence of carbon atoms, the electronic structure of C–MoO2 has been properly adjusted, and the loaded small Ru nanoparticles provide a fast water dissociation rate and moderate H adsorption strength. In electrochemical studies under a pH‐universal environment, Ru/C–MoO2 electrocatalyst exhibits a low overpotential at a current density of 10 mA cm−2 and has a low Tafel slope. Meanwhile, Ru/C‐MoO2 has excellent stability for more than 100 h at an initial current density of 100 mA cm−2. [ABSTRACT FROM AUTHOR]

Boron hydrides release an abundant amount of hydrogen in the presence of a suitable catalyst. Accelerating bimolecular activation kinetics is the key to designing cost‐effective catalysts for borohydride hydrolysis. In this study, the bimolecular activation of a polar O–Co–P site demonstrated superior hydrogen‐generation kinetics (turnover frequency, TOF = 37 min−1, 298 K) and low activation energy (41.0 kJ mol−1) close to that of noble‐metal‐based catalysts. Through a combination of experiments and theoretical calculations, it was revealed that the activated dangling oxygen atom in the Co–O precursor effectively replaced via surface‐phosphorization because of strong electronic interactions between the dangling oxygen and P atoms. This substitution modulated the local coordination environment and electronegativity around the surface Co sites and formed a new polar O–Co–P active site for optimizing the activation kinetics of ammonia borane and water. This strategy based on bimolecular activation may create new avenues in the field of catalysis. [ABSTRACT FROM AUTHOR]

Distributed generators are more expected with the capability to continue supporting power to local critical loads in both intended and unintended islanding conditions, in addition to its house‐keeping functions of grid‐connected condition. With this purpose, this paper proposes a control strategy of single‐phase grid‐connected inverter with both decoupled power control capability for grid‐connected mode and load voltage regulation capability for standalone mode. It also enables automatic voltage regulation on point of common coupling, which enables seamless transfer after islanding occurrence. An impedance model is disclosed to analyze the operation mechanism during transient state, with further investigations on both the effect of system parameters in different modes and the system operating features. Simulation and experimental results are provided to evaluate its effectiveness. [ABSTRACT FROM AUTHOR]

Bismuth‐based compounds with high capacity and durability are still challenging in Li‐ion batteries (LIBs). In this article, Bi2S3 nanorods hosted on reduced graphene oxide nanosheets (Bi2S3/rGO, BSG) are successfully prepared using molecular precursor pyrolysis strategy. 1D nanorod architecture possesses preeminent kinetic characteristics, shortening the ion diffusion path and increasing the contact area between electrode and electrolyte. The large specific surface area and charge polarization of rGO at the interface promote charge transfer. The capacity of material (BSG‐400) reaches 558.4 mAh g−1 at 0.2 A g−1 after 200 cycles. The anode properties of the composite outperform those of pristine Bi2S3. The introduction of graphene enables the interfacial interaction between rGO and Bi2S3. The closely contact interface improves the conductivity and lithium storage performances of Bi2S3. The regulatory effect of rGO on the electronic density of states and band gap of Bi2S3 has been demonstrated by theoretical calculation. The synthetic approach has the advantages of universality, simple operation procedure, and strong repeatability. This research provides some ideas for the preparation of other metal sulfides/rGO nanomaterials and their application in battery research. [ABSTRACT FROM AUTHOR]

For most Mo‐based electrocatalysts, the hydrogen evolution reaction (HER) activity depends on their own active structural defects or extrinsic transition metal centers. In this work, in order to combine the advantages of these two different active centers, a solid‐phase interface reaction (SPIR) strategy is proposed, which simultaneously introduces oxygen vacancies (VO) and metal centers (Ru) into the 2D Mo‐based catalyst. Briefly, this SPIR occurs at the interface between MoS2 and RuO2 nanoparticles of the RuO2/MoS2 precursor when overcoming the kinetic barriers at a suitable temperature under an Ar atmosphere. Since the adjacent parts of RuO2 and MoS2 are converted to Ru and MoO2 in situ, a composite system MiSC‐1 containing a large amount of active Ru and VO on MoO2 plane is obtained. Furthermore, theoretical calculations confirm the proposed mechanism of SPIR. MiSC‐1 shows excellent stability and catalytic performance in the HER, with an overpotential value of 12 mV at 10 mA cm−2 in 1.0 M KOH. Additionally, MiSC‐1 exhibits excellent performance in the hydrolysis of ammonia borane. This report will provide a versatile platform for the preparation of a multi‐component catalyst with high total activity as well as the identification of the structural details of the catalysts. [ABSTRACT FROM AUTHOR]

Purpose: Breast cancer is the most common cancer in women. The aim of this study was to build a prognostic signatures model based on the immune score of the ESTIMATE algorithm to predict survival of breast cancer patients. Methods: The RNA‐seq expression data and clinical characteristics of patients were derived from TCGA and GSE88770 of GEO. The ESTIMATE algorithm was used to calculate the patients' immune scores and to obtain DEGs. The LASSO Cox regression model was applied to select prognostic genes. Survival analysis and the ROC curve were used to evaluate the predictive efficacy of the prognostic signatures model. Independent prognostic factors of breast cancer were assessed using the Cox regression analyses, and a nomogram was constructed to enhance the clinical value. Results: Based on the immune score, we found that the high‐score group showed better clinical outcomes than the low‐score group. Twenty‐five (25) genes of 616 DEGs were confirmed as prognostic signatures through the LASSO Cox regression. The risk score for each patient was calculated according to the prognostic signatures. Survival analysis showed that the low‐risk group had longer overall survival than the high‐risk group. We also found that the risk score was an independent prognostic factor. To improve the clinical application value, a nomogram combing the risk score according to the 25‐gene prognostic signatures and several clinicopathological prognostic factors was constructed. Conclusions: This study revealed the significance of immune infiltration and constructed a 25‐gene prognostic signatures model, that has a strong prognostic value for patients with breast cancer. [ABSTRACT FROM AUTHOR]

Summary: Battery energy stored single‐phase quasi‐Z‐source inverter photovoltaic (BES‐qZSI‐PV) power system shows many advantages in comparison with other tri‐port inverter‐based PV power systems. However, the existing BES‐qZSI‐PV power system does not work at night or cloudy day because of its circuit limitation. This paper proposes a 24‐h operational BES‐qZS‐PV system by the following approaches: (1) the main power circuit is proposed for the day and night operation; (2) the detailed circuit models including the DC model and the second‐harmonics ripple model are built by considering scenarios of day and night operations; (3) the design method of quasi‐Z‐source network parameters is proposed to meet the requirement of day and night operations; and (4) the control strategy is proposed to achieve the high‐performance system operation all the time and seamless transition between day and night operation. After theoretical modeling and analysis, the built models are verified by comparing their calculation results with the circuit‐based simulation and experimental results. The proposed single‐phase BES‐qZSI‐PV power system is tested; experimental and simulation results are captured when the system operates in day, night, and transition to validate the proposed 24‐h operational BES‐qZSI‐PV system. [ABSTRACT FROM AUTHOR]

With the real-time changes of wind speed and operating conditions, it is a challenge to fully tap the active power regulation ability and improve the control performance of automatic generation control (AGC) in a wind farm (WF). The essence of tapping the active power regulation ability is to realise the coordination and complementarity of each wind turbine's (WT's) dynamic adjustment performance (DAP). To address this, a novel data mining method is developed to derive the internal relations between WTs' output power and pitch angle, impeller speed and pitch angle during the power adjustment process, and a unified mechanism model is established to describe DAP of WTs. Based on the discovered relationship between WTs' DAP and its operating states, an active power distribution algorithm and a dynamic interval control method are proposed. Then, an active power dynamic interval control strategy that has been implemented using Java script in MyEclipse for WFs is further developed. The control strategy has been tested and applied in a 50 MW WF in northwest China. The preliminary results showed that the control strategy has improved the rapidity and accuracy of AGC in the WF. [ABSTRACT FROM AUTHOR]

A new method to enhance the compressive strength of corrugated cartons is proposed in this study. The work aims to carry out compression tests on the corrugated carton to analyze the deformation and compressive capacity of the carton under the indentation condition of different shapes. First, compression tests are carried out on nonindentation cartons, one‐line indentation cartons, unclosed rhombus indentation cartons, rhombus indentation cartons, and cross‐indentation cartons to record their maximum compressive force. Second, by comparing the deformation of different cartons, it is found that rhombus indentation and cross‐indentation have the greatest influence on the compressive strength of cartons. Rhombus indentation will enhance the compressive strength of the carton, while cross‐indentation will reduce it. Third, ANSYS Workbench is used to analyze the buckling of cartons, and the maximum compressive force of nonindentation cartons and rhombus indentation cartons is obtained. Finally, through the comparison of the finite element method and experiments, it is concluded that rhombus indentation can improve the compressive strength of cartons, which is of great significance to the industrial production of cartons. [ABSTRACT FROM AUTHOR]

This study proposes an induction motor drive system based on the LC filter integrated quasi‐Z source indirect matrix converter (QZS‐IMC). The proposed drive system shows the following features: (i) variable voltage control of inductor motor is achieved by the rectifier stage and variable frequency control is achieved by the inverter stage; (ii) automatic low voltage ride through ability enhances capability of the proposed drive against grid voltage sag; (iii) wide voltage gain range ensures the drive system with high performance in wide speed range; (iv) there is no additional input filter. The voltage control implementation in the rectifier stage is proposed to benefit low voltage stress and low converter loss. The control method combines motor vector control, minimum shoot‐through duty cycle and maximum modulation indexes. As a result, the input power supply voltage and dc‐link voltage are maximally utilised and the power loss is reduced. Simulation and experimental results verify the proposed QZS‐IMC motor drive system. [ABSTRACT FROM AUTHOR]

Summary: The existing model of LC filter integrated quasi‐Z source indirect matrix converter (QZS‐IMC) was derived using the DC circuit modeling method, which is mainly effective in DC circuit. As an ac circuit, the existing voltage boost ratio model of LC filter integrated QZS‐IMC exhibits a big error from the real boost ratio. Moreover, current amplitude and phase angle of QZS network were not considered in the existing model. This paper proposes a new comprehensive model of LC filter integrated QZS‐IMC taking into account the circuit's ac characteristics. The new model shows that voltage boost ratio is strongly related to QZS network inductance, capacitance, and frequency of input power supply. It can be concluded from the new model that the boost ratio is higher than 1/(1 − 2D), which is the boost ratio of existing model. Moreover, the new model shows that power factor affects voltage gain of QZS‐IMC system. The new model is compared with the existing model, circuit simulation, and experimental test. The results verify the new model and analysis. [ABSTRACT FROM AUTHOR]

Objective: To investigate the blood flow Doppler parameters of the anterior cerebral artery (ACA) in foetuses with hypoplastic left heart syndrome (HLHS). Methods: Doppler parameters (peak systolic velocity [PSV], end‐diastolic velocity [EDV], time‐averaged maximum velocity [TAMXV] and pulsatility index [PI]) and biometric parameters were measured in two anatomical segments of the ACA (S1 and S2) and in the middle cerebral artery (MCA) in 35 HLHS foetuses and 73 gestational age‐matched normal foetuses. Correlations between the cerebral artery PIs and head circumference (HC) were assessed. Results: Both EDV and TAMXV of the ACA and MCA in the HLHS group were significantly higher than in the normal group (P <.05). The PI of the ACA and MCA in the HLHS group were significantly lower than in the normal group (P <.05). ACAS1PI and ACAS2PI in the HLHS foetuses with retrograde blood flow in the aortic isthmus (AoI) were significantly lower than those of HLHS foetuses without retrograde blood flow in the AoI (P <.05). ACAS2PI was significantly lower than ACAS1PI in the HLHS foetuses with retrograde blood flow in the AoI (P =.047). The abnormal rates of ACAS1 and ACAS2 were significantly higher than that of the MCA (P <.05) in the HLHS group. The HC and biparietal diameter were significantly lower in the HLHS group than in the control group (P <.05). HC was correlated with the PIs of ACAS1, ACAS2 and the MCA in the HLHS group (P <.05). Conclusion: A redistribution of foetal cerebral blood flow appeared in HLHS, and the measurement of ACA PI might provide early information on brain hypoxia. [ABSTRACT FROM AUTHOR]

The existing single‐phase, quasi‐Z‐source inverter (qZSI), photovoltaic (PV) power system with integrated battery energy storage (BES), abbreviated as BES‐qZSI‐PV power system, has several well‐known advantages, but cannot operate at night because there is no PV power input. In this study, a solution to overcome this issue is proposed. First, the power circuit of the conventional BES‐qZSI‐PV topology is modified to allow its operation at both day and night. Then, the system model for the night‐operation mode is built and a qZS network parameters' design method to limit the double‐line frequency harmonic at the dc side is developed. A control strategy to ensure the high‐performance operation of the system at all times, is proposed. Based on an experimental platform of single‐phase BES‐qZSI‐PV power system, three groups of experimental tests with different qZS network parameters and battery voltages are carried out to verify the model and parameters design method by means of comparing the experimental, circuit‐based simulated, and model‐based calculated results. The proposed BES‐qZSI‐PV system performance is experimentally evaluated in steady‐state operation and day‐to‐night transit operation, as well as by the power efficiency curves in day‐ and night‐modes. [ABSTRACT FROM AUTHOR]

Commonly, carbon layer was a suitable choice to enhance the conductivity and reduce the large volume effect of Ni2P nanoparticles (NPs) in electrochemical applications. The doped nitrogen (N) and phosphorous (P) atoms in carbon could further improve its performance. In this paper, core‐shell structure Ni2P@N, P‐co‐doped carbon (Ni2P@N, P−C) NPs were loaded onto reduced graphene oxide nanosheets (GN) to form new composite serial Ni2P@N, P−C/GN, which was designed for the combination of these merits and successfully obtained by two‐step method (firstly hydrothermal process and secondly phosphorization process). As anodes for LIBs and SIBs, the responding electrochemical studies showed the Ni2P@N, P−C/GN‐0.4 electrode exhibited an outstanding specific capacity of 450 mA h g−1 at 5 A g−1 after 2000 cycles in lithium‐ion batteries (LIBs) and maintained 110 mA h g−1 at 2 A g−1 after 3000 cycles in sodium‐ion batteries (SIBs), respectively. These results showed that Ni2P@N, P−C/GN material could be an excellent candidate for energy storage area. [ABSTRACT FROM AUTHOR]

Breast cancer is one of the leading fatal diseases for women worldwide who cannot have surgery typically have to rely on systemic chemotherapy to extend their survival. Doxorubicin (DOX) is one of the most commonly used chemotherapeutic agents against breast cancer, but acquired resistance to DOX can seriously impede the efficacy of chemotherapy, leading to poor prognosis and recurrences of cancer. Resveratrol (RES) is a phytoalexin with pharmacological antitumor properties, but its underlying mechanisms are not clearly understood in the treatment of DOX‐resistant breast cancer. We used cell viability assays, cell scratch tests, and transwell assays combined with Western blotting and immunofluorescent staining to evaluate the effects of RES on chemoresistance and the epithelial‐mesenchymal transitions (EMTs) in adriamycin‐resistant MCF7/ADR breast cancer cells, and to investigate its underlying mechanisms. The results showed that a treatment of RES combining with DOX effectively inhibited cell growth, suppressed cell migration, and promoted cell apoptosis. RES reversed EMT properties of MCF7/ADR cells by modulating the connection between SIRT1 and β‐catenin, which provides a hopeful therapeutic avenue to conquer DOX‐resistance and thereby prolong survival rates in breast cancer patients. Resveratrol alleviates DOX‐resistance in breast cancer cells. Resveratrol reverses EMT properties. Resveratrol modulates SIRT1/β‐catenin signaling pathway. [ABSTRACT FROM AUTHOR]

A series of TixSn1–xO2 (0≤x≤1) solid solution nanocubes wrapped by reduced graphene oxide (TixSn1–xO2/rGO, TSGC) were designed and synthesized for the application exploration as anode material in lithium ion batteries. When graphene oxide (GO) and K2TiO(C2O4)2 (PTO) were mixed in aqueous ambience, the TiO(C2O4)22− ions were not absorbed onto GO surface by the strong electrostatic repulsion force of the similarly negative‐charged surfaces. When Sn4+ ions were added to the mixture, they were easily adsorbed onto the GO surface. At the same time, Sn4+ ions were also easily coordinated by the carboxyl groups of the PTO species. After the followed hydrothermal and heat treatments, the desired 3D nanoarchitecture composites were obtained. Interestingly, in this TixSn1–xO2/rGO series, the Ti0.74Sn0.26O2/rGO sample exhibited the highest specific capacity of 514 mA h g−1 at 0.1 A g−1 even after 1000th cycles (nearly 100 % efficiency). Such promising electrochemical results are attributed to the 3D integrated structure by achieving better electrical contact between the active materials to shorten ion transport pathways, which highlights the synergistic effect from combining the TixSn1–xO2 nanocubes and rGO films. Additionally, the lithium storage mechanism of the as‐prepared TixSn1–xO2/rGO has been studied via in‐situ X‐ray diffraction (XRD) measurements for the first time. A series of cube‐like TixSn1–xO2/rGO composites were fabricated via a facile coordination strategy. When used as anode materials for lithium ion battery, the Ti0.74Sn0.26O2/rGO sample exhibited the high capacity and extremely cycling stability, which highlight its potential applications in energy issues. [ABSTRACT FROM AUTHOR]

The treatment of complicated long segment strictures remains to a challenge, and the substitution urethroplasty treatment is often accompanied by subsequent tissue fibrosis and secondary stricture formation. In situ injection of human adipose tissue‐derived stem cells (hADSC) could potential be applied for prevention of urethral fibrosis, but the cells transplantation alone may be insufficient because of the complicated histopathological micro‐environmental changes in the injury site. This study investigated whether miR‐21 modification can improve the therapeutic efficacy of ADSCs against urethral fibrosis to limit urethral stricture recurrence. MiR‐21‐modified ADSCs (miR‐21) were constructed via lentivirus‐mediated transfer of pre‐miR‐21 and GFP reporter gene. In vitro results suggested that miR‐21 modification can increase the angiogenesis genes expression of ADSCs and enhance its anti‐oxidative effects against reactive oxygen species (ROS) damage. In vivo results showed that miR‐21 modification contributes to increased urodynamic parameters and better formation of the epithelium and the muscle layer as compared to ADSCs transplantation alone groups. The results demonstrated that miR‐21 modification in ADSCs could improve urethral wound healing microenvironment, enhance stem cell survival through ROS scavenging and promote the neovascularization via regulating angiogenic genes expression, which eventually increase the ADSCs' therapeutic potential for urethral wound healing. [ABSTRACT FROM AUTHOR]

Objectives: Sam68 (Src-associated in mitosis 68 kDa), a substrate for tyrosine kinase c-Src during mitosis, is up-regulated in a variety of human cancers and acts oncogenically promoting tumour progression. This study has explored biological function and clinical significance of Sam68 in non-Hodgkin's lymphoma (NHL). Materials and methods: To examine Sam68 expression in NHL, clinically, eight diffuse large B-cell lymphomas and four reactive lymphoid hyperplasia fresh-frozen tissues were obtained for western blot and quantitative real-time PCR analyses. Using immunohistochemical staining, paraffin wax embedded sections from 164 cases of NHL patients were used to evaluate prognostic value of Sam68. Cell Counting Kit-8 (CCK-8) and soft agar colony assays were conducted to investigate the role of Sam68 in cell viability and cell proliferation respectively. Furthermore, effects of Sam68 on cell adhesionmediated drug resistance (CAM-DR) was determined by CCK-8 assay and flow cytometric analysis. Results: Expression status of Sam68 inversely correlated with clinical outcomes of patients with NHL, and it was also an independent prognostic factor for the outcomes. In addition, Sam68 was associated with proliferation of NHL cells. Knockdown of its gene inhibited cell proliferation and colony formation by delaying cell cycle progression. Furthermore, OCI-Ly8 and Jeko-1 cells adhering to FN and HS-5 expressed higher Sam68 protein, compared to their suspension counterparts. Sam68 promoted cell adhesion-mediated drug resistance (CAM-DR) via the AKT pathway. Conclusions: Increased Sam68 expression in NHL resulted in poor prognosis, and it promoted CAMDR in NHL via AKT. [ABSTRACT FROM AUTHOR]

The hippocampus receives dopaminergic projections from the ventral tegmental area ( VTA) and substantia nigra. These inputs appear to provide a modulatory signal that influences hippocampus-dependent behaviors. Enhancements in working memory performance have been previously reported following acute smoking/nicotine exposure. However, the underlying mechanism remains unclear. This study investigated the effects of nicotine on spatial working memory ( SWM) and the mechanisms involved. Delayed alternation T-maze task was used to assess SWM. In situ and gel gelatin zymography were used to detect matrix metalloproteinase-9 ( MMP-9) in SWM. Systemic or local (intra- VTA) administration of nicotine significantly improves SWM, which was accompanied by increased MMP-9 activity in dorsal hippocampus ( dHPC). Intra- dHPC administration of MMP inhibitor FN-439 abolished the memory enhancement induced by intra- VTA nicotine infusion. FN-439 had no effect on locomotor behavior. Our data suggest that intra- VTA nicotine infusion activates MMP-9 in dHPC to improve SWM in rats. [ABSTRACT FROM AUTHOR]

The preparation of conducting γ-aminopropyltriethoxysilane halloysite (APHNTs)/polyaniline (PANI) coaxial tubular nanocomposite was conducted via in situ oxidative polymerization after the surface modification of the halloysite nanotubes' (HNTs) surface with γ-aminopropyltriethoxysilane (γ-APTES) as modifier and aniline as monomer in the presence of hydrochloric acid (HCl). The products were characterized by Fourier transform infrared spectroscopy analysis, X-ray diffraction, and thermogravimetric analysis. The surface coatings of the γ-APHNTs and the γ-APHNTs/PANI hybrids were characterized with X-ray photoelectron spectroscopy. The morphology of γ-APHNTs/PANI nanocomposites were examined by scanning electron microscopy and transmission electron microscopy. The electrical conductivities of the γ-APHNTs/PANI were measured using SDY-4 Four-Point Probe Meter. The results showed that the concentration of HCl had no effect on the morphologies and the electrical conductivities of the γ-APHNTs/PANI nanocomposites increased with more HCl added. POLYM. COMPOS., 36:1759-1766, 2015. © 2014 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Polyaniline/graphene (PANI/GN) nanocomposites were fabricated via in-situ oxidative polymerization of aniline in the presence of cetyltrimethylammonium bromide (CTAB) modified graphene (CGN) in 1M hydrochloric acid (HCl) solution. The morphology and structure of PANI/GN samples were investigated by Fourier transform infrared spectrum, X-ray diffraction, ultraviolet and visible spectrum, thermogravimetric analysis, field-emission scanning microscope (FE-SEM), and transmitting electron microscopy (TEM). The conductivities of the PANI/GN nanocomposites were measured using four-probe electrical conductivity measurement. The results indicated that the GN sheets disperse into the form of monolayer or stack few layers in PANI matrix. The GN sheets serve as a support material for PANI particles and the structure of GN covered with PANI nanoparticles were confirmed by FE-SEM and TEM. The electrical conductivities of the PANI/GN samples have been improved compared with pure PANI prepared in the similar condition. POLYM. COMPOS., 36:1767-1774, 2015. © 2014 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Quasi‐Z source cascaded multilevel inverter (qZS‐CMI) is an emerging topology applied to photovoltaic (PV) power system. It can overcome disadvantages of conventional CMI‐based PV power system, because of achieving the balanced dc‐link voltage through using its boost ability, and saving one‐third modules. At present, there was not literature to disclose the modelling and controller design for qZS‐CMI‐based three‐phase grid‐tie PV power system. In this study, a control scheme for three‐phase qZS‐CMI‐based grid‐tie PV power system is proposed, where distributed maximum power point tracking (MPPT) and constant dc‐link peak voltage are achieved for all qZS H‐bridge inverter (qZS‐HBI)‐based PV modules, with grid‐injected power in unity power factor. The detailed controller parameter design is demonstrated by using Bode plots and the built models of qZS‐HBI‐based PV module and whole system. A test bench of 7‐level three‐phase qZS‐CMI‐based PV power system is built. Simulation and experimental results validate the proposed control scheme and design method. [ABSTRACT FROM AUTHOR]

A new method of imputation for left-censored datasets is reported. This method is evaluated by examining datasets in which the true values of the censored data are known so that the quality of the imputation can be assessed both visually and by means of cluster analysis. Its performance in retaining certain data structures on imputation is compared with that of three other imputation algorithms by using cluster analysis on the imputed data. It is found that the new imputation method benefits a subsequent model-based cluster analysis performed on the left-censored data. The stochastic nature of the imputations performed in the new method can provide multiple imputed sets from the same incomplete data. The analysis of these provides an estimate of the uncertainty of the cluster analysis. Results from clustering suggest that the imputation is robust, with smaller uncertainty than that obtained from other multiple imputation methods applied to the same data. In addition, the use of the new method avoids problems with ill-conditioning of group covariances during imputation as well as in the subsequent clustering based on expectation-maximization. The strong imputation performance of the proposed method on simulated datasets becomes more apparent as the groups in the mixture models are increasingly overlapped. Results from real datasets suggest that the best performance occurs when the requirement of normality of each group is fulfilled, which is the main assumption of the new method. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A novel synthesis route for mesoporous carbon (MC) nanosheets were developed using halloysite nanotubes (HNTs), a type of natural clay that is structurally and chemically similar to mineral kaolinite, as inorganic matrix and using polypyrrole (PPy) as carbon precursor by a template-like method. First, PPy/HNT hybrids were prepared by in situ oxidative polymerization. Carbon (C)/HNT hybrids were further obtained by pyrolysis of the PPy/HNT hybrids. MC was obtained after the removal of inorganic template by hydrochloric acid/hydrofluoric acid mixture at the end. Both the C/HNT and the MC were characterized by Fourier transform infrared spectroscopy analysis, X-ray diffraction, Raman spectra measurement, and high-resolution transmission electron microscopy. The MC was also characterized with specific surface area (BET). The results showed that the MC obtained was almost amorphous carbon. The increase in the ratio of [HNTs template]/[pyrrole monomer] led to an increase in the BET-specific surface area. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013 [ABSTRACT FROM AUTHOR]