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Artificial synapses and neurons are recognized as key elements in building bioinspired, neuromorphic computing systems. However, synaptic and neuronal elements that have compatible material systems with each other with high scalability and biorealistic dynamics are yet to be demonstrated. Here we report a two-terminal memristive synapse that can realize short-term and long-term plasticity in both potentiation and depression processes. The Ag nanoclusters introduced at the interface can move, connect and redistribute in response to applied pulses, where their electrochemical migration and thermodynamic relaxation in dielectrics compete with each other and faithfully emulate the synaptic and neuronal dynamics in biology, which in turn allows the same devices to exhibit various synaptic functions and neuronal spiking in a scalable manner. The evolution dynamics of Ag nanoclusters was verified using high resolution transmission electron microscopy and compositional analyses. Based on the inherent state modulator and timing mechanism offered by such dynamics, the devices were able to naturally implement complex functions including metaplasticity, asynchronous classical conditioning and spike-timing-dependent plasticity without needing intentionally designed overlapping pulses, thus paving the way for the construction of intelligent neuromorphic systems capable of encoding and processing spatiotemporal information.

Wind turbine generators (WTGs) can provide short-term frequency support at a frequency event via the stepwise inertial control (SIC) scheme. However, WTGs deviate from the maximum power point tracking (MPPT) operating point when SIC is implemented. A reasonable trade-off between the effectiveness of frequency support and the aerodynamic efficiency of WTGs should be reached in SIC parameters configurations. This paper proposes a modified SIC scheme where the SIC parameters are determined with consideration of wind energy capture losses. Simulation results validate that the proposed scheme improves the system frequency response without causing significant wind energy capture losses.

Megacrystalline uraninite (up to one centimeter in size) represents one of the most important discoveries in uranium mineralogy in the western margin of the Yangtze Block and even in China in recent years. However, the genesis of megacrystalline uraninite remains controversial. In this study, the megacrystalline uraninite found in the felsic and quartz veins in the Haita area is examined for the first time. The study examined the geochemical characteristics of uraninite in the two veins and resulted in two primary findings. (1) The genesis of the uraninite was likely intrusive and was closely related to partial melting. (2) The quartz vein and feldspar vein are cogenetic and have a simple differentiation evolution relationship. Therefore, the partial melting of felsic materials during migmatization may be the most important mechanism of uranium mineralization in the study area. Furthermore, further simple fractional crystallization may be another important mechanism for the formation of megacrystalline uraninite. This study enriches the REE database of uraninite in uranium deposits worldwide, which is meaningful for studying the genesis of megacrystalline uraninite.

Pulmonary hypertension is a progressive fatal disease that currently has no specific therapeutic approaches. In this study, dsRNA-dependent protein kinase (PKR) was considered a candidate molecule in pulmonary hypertension. We demonstrated that PKR is activated in the endothelium of experimental pulmonary hypertension models. Deletion of PKR or treatment with the PKR activation inhibitor C16 inhibited the development of pulmonary hypertension. To explore the mechanism of PKR in pulmonary hypertension, we detected its downstream signaling and found that PKR knockout represses apoptosis-associated speck-like protein containing CARD (ASC) activation to inhibit high mobility group box 1 (HMGB1) and interleukin-1 beta release. To further explore whether ASC mediates the pro-pulmonary hypertension role of PKR, we used ASC deletion mice and found that ASC deletion inhibits the development of pulmonary hypertension and the release of HMGB1 and interleukin-1 beta. Furthermore, we co-cultured pulmonary arterial endothelial cells (PAECs) and pulmonary arterial smooth muscle cells (PASMCs) and found that endothelial PKR promotes PASMCs proliferation through the release of HMGB1 and interleukin-1 beta. In conclusion, these data indicate that endothelial PKR promotes the excessive proliferation of PASMCs by inducing ASC activation to release HMGB1 and interleukin-1 beta, which lead to the development of pulmonary hypertension. Our study will provide a novel insight that PKR is a potential target in the future treatment of pulmonary hypertension.

With increased wind power penetration in modern power systems, wind turbine generators (WTG) are expected to provide the active power control (APC) for tracking a desired power reference from system or wind farm operators. In practice, the pitch angle control (PAC) and the rotor speed control (RSC) methods can be used for APC in variable-speed variable-pitch WTGs, but the latter using turbine inertia as energy buffer is more attractive due to less pitch activation and higher wind energy production. For existing RSC methods, when the rotor speed reaches the upper speed limit at high wind speed or low power reference, they will actually become PAC to follow active power command, which also results in frequent pitch angle manipulation and considerable fatigue on the pitch servo system. To overcome this drawback, this paper proposes a new APC strategy integrating the rotor speed and pitch angle regulation. By utilizing the kinetic energy of rotor inertia at any pitch position (zero as well as non-zero pitch angle), this strategy can effectively avoid frequent action of pitch actuator while sustaining dispatched active power. The proposed method is verified by the fatigue, aerodynamics, structures, and turbulence-based simulations and wind turbine simulator-based experiments.

Pulmonary hypertension (PH) is a progressive and life-threatening disease with poor prognosis despite many advances in medical therapy over the past 20 years. Novel therapies which target on the underlying pathology of PH are still urgent to be met. TPN171H is a recently found new compound that exhibits potent pharmacological effects in PH via inhibiting phosphodiesterase type 5 (PDE-5). However, as one icariin derivative, the anti-inflammatory effects of TPN171H for treating PH are not clear. The present study was designed to investigate the therapeutical effect of TPN171H against inflammation in PH and reveal the underlying mechanism. Hypoxia and monocrotaline (MCT)-induced PH rat models were established, which were treated by oral administration of TPN171H (5, 25 mg/kg/d) or sildenafil (25 mg/kg/d). The right ventricle systolic pressure (RVSP), right ventricle hypertrophy index (RVHI) and vascular remodeling were measured. The results suggested that TPN171H significantly reduced RVSP and RVHI, and reversed pulmonary vascular remodeling in rats with both models. Furthermore, in in vivo and in vitro research, our data suggested that TPN171H remarkably suppressed cathepsin B-mediated NLRP3 inflammasome activation, which may contribute to its therapeutical function for PH.

In the maximum power point tracking (MPPT) control of the wind power system, the tracking of the power curve corresponding to the maximum power point (MPP) is a means for obtaining the maximum wind energy efficiency. However, the traditional optimal power curve is not involved with the dynamic response characteristic of wind turbine (WT). Hence, it is not the actually optimal power curve tracked by the rotor speed to capture the maximum wind energy. This phenomenon is especially serious in low-speed wind power generation systems with large moments of inertia of turbines. As a matter of fact, in most servo-track control problems involved with benefit optimization, the tracking to the reference input is not the final aim of the control, instead, it is just a means for the control to obtain a best benefit. Therefore, when the reference input changes too fast relative to the slow dynamics of the controlled object, it will be very difficult to be tracked and then the benefit will be degenerated. To solve this problem, this paper presented a optimization method to design a virtual reference input for replace the original one in the servo-track problem involved with benefit optimization, which is easier to be tracked and hence a higher benefit will be achieved. An application of this method in MPPT control of the wind turbines is implemented on a single mass model. The results show that the suboptimal rotor speed curve can replace the optimal rotor speed curve to obtain higher wind energy capture.

Switches between global sleep and wakefulness states are believed to be dictated by top-down influences arising from subcortical nuclei. Using forward genetics and in vivo electrophysiology, we identified a recessive mouse mutant line characterized by a substantially reduced propensity to transition between wake and sleep states with an especially pronounced deficit in initiating rapid eye movement (REM) sleep episodes. The causative mutation, an lle102Asn substitution in the synaptic vesicular protein, VAMP2, was associated with morphological synaptic changes and specific behavioral deficits, while in vitro electrophysiological investigations with fluorescence imaging revealed a markedly diminished probability of vesicular release in mutants. Our data show that global shifts in the synaptic efficiency across brain-wide networks leads to an altered probability of vigilance state transitions, possibly as a result of an altered excitability balance within local circuits controlling sleep-wake architecture., Science Advances, 6 (33), ISSN:2375-2548

Sleep-wake transitions are modulated through extensive subcortical networks although the precise roles of their individual components remain elusive. Using forward genetics and in vivo electrophysiology, we identified a recessive mouse mutant line characterised by a reduced propensity to transition between all sleep states while a profound loss in total REM sleep time was evident. The causative mutation, an Ile102Asn substitution in VAMP2, was associated with substantial synaptic changes while in vitro electrophysiological investigations with fluorescence imaging revealed a diminished probability of vesicular release in mutants. We conclude that the synaptic efficiency of the entire subcortical brain network determines the likelihood that an animal transitions from one vigilance state to the next.

Supplemental material, Supplementary_Figure for Estimation of Mean Variation in Prediction Probability for Prevalence of Hypertension in Middle-Aged and Older Chinese Using Probit Model by Minghui Yin and Caiping Liu in Asia Pacific Journal of Public Health

Supplemental material, CHARLS_2015_Release_Note for Estimation of Mean Variation in Prediction Probability for Prevalence of Hypertension in Middle-Aged and Older Chinese Using Probit Model by Minghui Yin and Caiping Liu in Asia Pacific Journal of Public Health

The variable-speed wind turbine (VSWT) is a dominant type of wind power generator. In order to improve wind energy production, its off-design performance has been considered for aerodynamic optimization, since it frequently operates at non-optimal tip speed ratio (TSR) in the maximum power point tracking (MPPT) mode. In this paper, the objective function for multi-point aerodynamic optimization is firstly derived as wind energy capture efficiency. Then, a new multi-point aerodynamic design method whose objective function can approximate wind energy capture efficiency is proposed. Since the proposed optimization aims to increase the closed-loop efficiency with a clear physical meaning, static aerodynamic performance and MPPT dynamics can be better coordinated and correspondingly higher wind energy production of VSWTs can be achieved. Finally, using the 1.5 MW and 5.0 MW VSWTs developed by National Renewable Energy Laboratory (NREL) as the baseline, the proposed method is verified by simulations with commercial software Bladed and experiment test on a wind turbine testbed.

A linearization model is obtained for a three-bladed horizontal-axis wind turbine (HAWT) consisting of blades and a drive-train. Sensitivity analysis of the degree of controllability (DOC) and maximum power point tracking (MPPT) efficiency with respect to the structural parameters of wind turbines is discussed by numerical simulations. It is observed from the simulation results that higher MPPT efficiency can be achieved with the increase of DOC. Based on the observation, this paper proposes a new integrated design method based on DOC to design and optimize the structural parameters of a HAWT. The designed turbine is tested by the commercial simulation software of wind turbines named Bladed. It is observed from simulations that when using the identical MPPT control strategy, the wind turbine whose structural parameters are optimized for a larger value of DOC can achieve higher MPPT performance.

A novel visible-light-responsive photocatalyst is fabricated by introducing g-C3N4 ultrathin films onto the surface of attapulgite (ATP) via a simple in-situ depositing technique, in which ATP was pre-grafted using (3-Glycidyloxypropyl) trimethoxysilane (KH560) as the surfactant. A combination of XRD, FT-IR, BET, XPS, UV–vis, TEM and SEM techniques are utilized to characterize the composition, morphology and optical properties of the products. The results show that with the help of KH560, g-C3N4 presented as ultrathin layer is uniformly loaded onto the surface of ATP by forming a new chemical bond (Si O C). Comparing with g-C3N4 and ATP, ATP/g-C3N4 exhibits remarkably enhanced visible-light photocatalytic activity in degradation of methyl orange (MO) because of its high surface area, appropriate band gap and the synergistic effect between g-C3N4 and ATP. To achieve the best photocatalyst, the ratio of g-C3N4 was adjusted by controlling the mass portion between ATP-KH560 and melamine (r = m (ATP-KH560)/m (melamine)). The highest decomposition rate of methyl orange (MO) was 96.06% when r = 0.5 and this degradation efficiency remained unchanged after 4 cycles, which is 10 times as that of pure g-C3N4 particles. Possible photocatalytic mechanism is presented.

In this paper, the relationship between the degree of controllability (DOC) of controlled plants and the corresponding quadratic optimal performance index in LQR control is investigated for the ele...

Since mechanical loads exert a significant influence on the life span of wind turbines, the reduction of transient load on drive-train shaft has received more attention when implementing a maximum power point tracking U+0028 MPPT U+0029 controller. Moreover, a trade-off between the efficiency of wind energy extraction and the load level of drive-train shaft becomes a key issue. However, for the existing control strategies based on nonlinear model of wind turbines, the MPPT efficiencies are improved at the cost of the intensive fluctuation of generator torque and significant increase of transient load on drive train shaft. Hence, in this paper, a nonlinear controller with variable parameter is proposed for improving MPPT efficiency and mitigating transient load on drive-train simultaneously. Then, simulations on FAST U+0028 Fatigue, Aerodynamics, Structures, and Turbulence U+0029 code and experiments on the wind turbine simulator U+0028 WTS U+0029 based test bench are presented to verify the efficiency improvement of the proposed control strategy with less cost of drive-train load.

Wind turbine simulators (WTSs), devised for pre-validation of control strategies for wind energy conversion system, commonly employ the inertia compensation scheme for reproducing mechanical behaviours similar to real wind turbines (WTs). However, it is found in this study that when a WT with large inertia is simulated, the time delay in command communication from control unit to motor driver, usually neglected in the existing inertia compensation scheme, results in the oscillating acceleration response and consequently leads to instability of the WTS system. As a result, the existing WTS is unable to stably simulate large-inertia WTs, which significantly limits its applicability. Hence, in this study, a linear discrete model of the inertia compensation part that considers time delay of acceleration observation and communication is developed. On the basis of this model, an improved inertia compensation scheme in which a high-order filter is introduced to eliminate the deviation of acceleration response caused by the two types of time delay is proposed. Finally, the improved inertia compensation scheme and its applicability to simulating a 600 kW WT developed by National Renewable Energy Laboratory are experimentally verified.

This study focuses on the development of optimal torque (OT) control, which is a commonly used method for maximum power point tracking (MPPT). Due to the sluggish response of wind turbines with high inertia, conventional OT control was improved to increase MPPT efficiency by dynamically modifying the generator torque versus rotor speed curve. An idea that tracking a local interval of wind speed where the wind energy is primarily distributed rather than the total range of wind speed variation is applied in this study. On this basis, an effective tracking range (ETR) that corresponds to the local interval of wind speed with concentrated wind energy distribution is proposed and an improved OT control based on ETR is developed. In this method, based on a direct relationship between ETR and wind conditions, the torque curve can be quickly optimised so that higher and more stable MPPT efficiency can be achieved under varying wind conditions. Meanwhile, MPPT efficiency enhancement by reducing tracking range without increasing torque discrepancy leads to a low cost of generator torque fluctuation and drive train load. Finally, simulations based on fatigue, aerodynamics, structures, and turbulence (FAST) code and experiments conducted on a wind turbine simulator are presented to verify the proposed method.

Wind turbine simulator (WTS) is an important test rig for validating the control strategies of wind turbines (WT). Since the inertia of WTSs is much smaller than that of WTs, the inertia compensation scheme is usually employed in WTSs for replicating the slow mechanical behavior of WTs. In this paper, it is found that the instability of WTSs applying the inertia compensation scheme, characterized by the oscillation of compensation torque, is caused by the one-step time delay produced in the acceleration observation. Hence, a linear discrete model of WTS considering the time delay of acceleration observation is developed and its stability is analyzed. Moreover, in order to stably simulate WTs with large inertia, an improved inertia compensation scheme, applying a first-order digital filter to mitigate deviation response induced by the time delay, is proposed. And, the criterion for selecting the filter coefficients is established based on the stability condition analysis. Finally, the WTS with the proposed scheme is validated by simulations and experiments.

Memristive devices with analog resistive switching characteristics are widely investigated nowadays for electronic synapses that facilitate memory and learning in neuromorphic computing hardware. It is therefore essential to understand and optimize the incremental switching behavior of the cells in order to enhance the functionality of memristive neural networks. Here we report a systematic study on the analog switching of bilayer oxide based memristive synapses and show that transition metal oxides with rich intermediate phases, such as WOx, are able to provide larger number of conductance states compared with oxides with few intermediate phases such as TaOx and HfOx. This could be attributed to the intrinsically different electrical properties of the intermediate phases that jointly contribute to the change of device conductance, in addition to that caused by the varied geometry of filaments during programming. Controlled studies adopting different materials, compositions and sequences of oxide bilayers reveal that the analog switching is mainly dominated by the switching layer, thus providing clues to the optimization of memristive devices for future neuromorphic applications.

From the perspective of integrated design, a new control topic is proposed by analyzing many common social phenomena. Which kind of controlled plant is better for control? Focus is on the key point that ``if such a plant exists, what properties does it need to have?" In this paper, the concept of ``better for control" is defined for the linear / linearized plant, which implies that the closed-loop control effect is better and controller gain is smaller with the same control strategy. A theoretical framework and features for the new control concept are introduced. Furthermore, contrology conjecture of the degree of controllability (DOC) is investigated as to which concept could depict the difference level of controllability between the controlled plants under the same control conditions. Based on the preliminary framework, we also present the research situation and prospect on the field.

In this study, a distributed interactive reactive power and voltage control (RPVC) using finite time consensus is proposed to enhance the efficiency and reliability of an AC/DC hybrid distribution network (HDN). By using the disturbed secondary voltage control with finite time consensus, the reactive power interaction between AC and DC subnets is reached, and also the coordination among multiple droop-controlled inverters in AC subnet is realized. Additionally, the proposed control ensures an accurate reactive power sharing, avoiding the problem of reactive power circulation among multiple inverters, and further improves the voltage quality. An AC/DC HDN with multiple distributed generators (DGs) is established in PSCAD/EMTDC, and the effectiveness and adaptability of distributed interactive voltage control and reactive power sharing strategy between AC and DC subnets are verified under various operating conditions.

Microbial hydroxylation of 17β-estradiol (1) with Penicillium brevicompactum, a fungal species not used in biotransformation so far, yielded four metabolites: 1, 3, 5-estratriene-3, 15α-diol-17-one (2); 1, 3, 5-estratriene-3, 6α, 17β-triol (3); 1, 3, 5-estratriene-3, 15α, 17β-triol (4); and 1, 3, 5-estratriene-3, 6α, 15α-triol-17-one (5). All the products were determined by 1H NMR, 13C NMR, two-dimensional NMR, and HRMS techniques. Compounds 3, 4, and 5 are reported for the first time via microbial transformation, and 5 is a new compound as far as we know. Possible metabolic pathway of 17β-estradiol via Penicillium brevicompactum was also proposed.

In a power factor correction (PFC) converter, an electrolytic capacitor (E-Cap), which has the advantages of a smaller volume and a low cost compared with other kinds of capacitors at the same voltage rating and capacitance value, is usually used to balance the difference between the pulsating input power and constant output power. However, the E-Cap has a bigger equivalent series resistance and the ripple current flowing through it will produce loss and heat, therefore, shortening its lifetime. So the E-Cap, a component that has the shortest life in a PFC converter, decides the lifetime of the power source. In this paper, the mathematical relationship between the root mean square (RMS) value of the E-Cap's ripple current and the converter's parameters are derived for a DCM boost PFC converter. The corresponding third input current harmonic is figured out for the optimal reduction of the RMS value of the high-frequency ripple current, so that the E-Cap's lifetime can be greatly improved. A method of fitting the duty cycle and the simplified circuit implementation are further proposed. Compared with the traditional control, the proposed minimum RMS value control also achieves an efficiency improvement as the critical inductance is increased and the peak and RMS current value of the power components are, therefore, decreased. The experimental results from a 120-W prototype are given to verify the effectiveness of the analysis.

This paper is concerned with the measure of degree of controllability (DOC) for linear system with external disturbance. A new measure of DOC, in which the initial condition is regarded as a random vector, is proposed in this paper by solving the fixed-time expected minimum-energy transfer control problem. Since this new measure is dependent on the statistical information of initial condition rather than its estimated value, it is more suitable to apply the proposed measure in the design and optimization of the structural parameters of controlled plants. Furthermore, the simulations on the NREL (National Renewable Energy Laboratory) CART3 wind turbine demonstrate that the relation of the proposed measure to turbine parameters (including rotor inertia and optimum tip speed ratio) coincides with that of the MPPT efficiency to turbine parameters. This indicates that the proposed measure is applicable to guide the design and optimization of the structural parameters of wind turbines. Meanwhile, a mass-spring-damper system is also simulated to validate the proposed measure.

This paper is concerned with the effects of redundant control inputs on the quadratic optimal performance index in finite-time optimal control. Actually, the effects of redundant control input on quadratic performance index is equal to study the effects of the redundant control input on the solution of Riccati differential equation (RDE). Hence, some sufficient conditions are presented to strictly decrease the solution of RDE with the column of input matrix increased. Especially, a necessary and sufficient condition is derived to strictly decrease the solution of the homogeneous RDE after control input extensions. Moreover, one sufficient condition is obtained, which guarantees that the minimum control energy index strictly decreases with input extension. It is shown that redundant control inputs can improve the system performance based on these results. Some examples are taken to illustrate the effectiveness of related problems.

Nitric oxide (NO) is emerging as a key regulator of diverse plant cellular processes. A major route for the transfer of NO bioactivity is S-nitrosylation, the addition of an NO moiety to a protein cysteine thiol forming an S-nitrosothiol (SNO). Total cellular levels of protein S-nitrosylation are controlled predominantly by S-nitrosoglutathione reductase 1 (GSNOR1) which turns over the natural NO donor, S-nitrosoglutathione (GSNO). In the absence of GSNOR1 function, GSNO accumulates, leading to dysregulation of total cellular S-nitrosylation. Here we show that endogenous NO accumulation in Arabidopsis, resulting from loss-of-function mutations in NO Overexpression 1 (NOX1), led to disabled Resistance (R) gene-mediated protection, basal resistance and defence against nonadapted pathogens. In nox1 plants both salicylic acid (SA) synthesis and signalling were suppressed, reducing SA-dependent defence gene expression. Significantly, expression of a GSNOR1 transgene complemented the SNO-dependent phenotypes of paraquat resistant 2-1 (par2-1) plants but not the NO-related characters of the nox1-1 line. Furthermore, atgsnor1-3 nox1-1 double mutants supported greater bacterial titres than either of the corresponding single mutants. Our findings imply that GSNO and NO, two pivotal redox signalling molecules, exhibit additive functions and, by extension, may have distinct or overlapping molecular targets during both immunity and development.

With the large scale accessing of wind power to the grid, the power system will withstand different types of active disturbances. In other words, in addition to the traditional step change of the active power caused by the generator outages or sudden change of load, the random fluctuation of the wind power will also cause a distinct deviation of the system frequency. Since different types of disturbances will cause different frequency response characteristics, it inevitably puts forward higher requirements for the optimal configuration of the primary frequency modulation capacity and governor parameters to synchronous generators in the system. For this reason, based on the electromechanical dynamic model which equivalent to the single machine, this paper analyzes the different characteristics of the primary frequency modulation under the step type likes generator outages or sudden change of load and the sinusoidal form likes wind power fluctuation. At the same time, the simulation results of the IEEE 3-machine 9-bus system based on the DIgSILENT further show that the governor aimed at single type active disturbance can not better adapt to other types. This paper will lay the foundation for the primary frequency optimizing configuration of the power system which considering multiple types of active disturbances.

Background Breast cancer (BC) is the most common cancer in women worldwide and leading cause of cancer deaths indeveloping countries. There is very limited data on BC in the Central African Republic. The purpose of this study was to describe the epidemiological and histopathological characteristics of BC in Bangui. Methods This retrospective study reviewed cancer data registries and medical records from the Pathology Unit of the National Laboratory in Bangui and the General Surgery and Gyneacology service from 2003 to 2015. A questionnaire was designed to collect information and data was analysed using descriptive and inferential statistical methods. Results In total, 174 cases of BC were recorded, with an average annual frequency of13.4 cases per year. The age of the women at diagnosis varied from 16 to 90 years with a median of 45.5 years and InterQuartile range (IQR) 18 years. The age group of 45–54 years represented the majority of the study population (n = 51, 29.3%).About 25.9%ofthe patients were non-educated and 85.6% lived in cities. Over 48 % of the women were housewives with a moderate economic status (n = 99, 56.9%). Sixty nine percent of the specimens received at the pathology unit were pieces of breast tumour. Invasive ductal carcinoma (n = 113, 64.9%) was the main histological form and most of the tumours were of Grade III (n = 14, 46.7%). The only imaging assessment was ultrasound performed in (n = 53, 30.4%) women. Surgery was performed in (n = 166, 95.4%) patients, while (n = 159, 91.4%) received complementary chemotherapy. At the end of the study, 84.5%of the cases had died, 12.1% were alive and 3.4% were considered “lost to follow-up”. Conclusion BC is an important public health problem and affected most of the younger Central African women. Epidemiological and histological characteristics are more or less common to those described other developing countries. It is imperative to improve the awareness of health care institutions and women on the burden of BC, to carry out early screening of BC, and to strengthen the capacity of women’s health care system.

Background Breast cancer (breast Ca) is recognised as a major public health problem in the world. Data on reproductive factors associated with breast Ca in the Central African Republic (CAR) is very limited. This study aimed to identify reproductive variables as risk factors for breast Ca in CAR women. Methods A case–control study was conducted among 174 cases of breast Ca confirmed at the Pathology Unit of the National Laboratory in Bangui between 2003 and 2015 and 348 age-matched controls. Data collection tools included a questionnaire, interviews and a review of medical records of patients. Data were analysed using SPSS software version 20. Odd ratios and 95% confidence intervals (CI) for the likelihood of developing breast Ca were obtained using unconditional logistic regression. Results In total, 522 women with a mean age of 45.8 (SD = 13.4) years were enrolled. Women with breast Ca were more likely to have attained little or no education (AOR = 11.23, CI: 4.65–27.14 and AOR = 2.40, CI: 1.15–4.99), to be married (AOR = 2.09, CI: 1.18–3.71), to have had an abortion (AOR = 5.41, CI: 3.47–8.44), and to be nulliparous (AOR = 1.98, CI: 1.12–3.49). Decreased odds of breast Ca were associated with being employed (AOR = 0.32, CI: 0.19–0.56), living in urban areas (AOR = 0.16, CI: 0.07–0.37), late menarche (AOR = 0.18, CI: 0.07–0.44), regular menstrual cycles (AOR = 0.44, CI: 0.23–0.81), term pregnancy (AOR = 0.26, CI: 0.13–0.50) and hormonal contraceptive use (AOR = 0.62, CI: 0.41–0.93). Conclusion Breast Ca risk factors in CAR did not appear to be significantly different from that observed in other populations. This study highlighted the risk factors of breast Ca in women living in Bangui to inform appropriate control measures.

The present study aimed to investigate the role of abnormal body mass index (BMI, kg/m2) in the depression-CRP (C-reactive protein) relationship in a healthy middle-aged and elderly Chinese population. Analytical samples were drawn from the China Health and Retirement Longitudinal Study (CHARLS), and participants were categorized by different BMI levels. Depressive subtypes were evaluated both at baseline and follow-up using the Center for Epidemiology Studies Depression scale. Hs-CRP and other variables were measured at baseline. Multiple linear regression analyses were used to evaluate the cross-sectional and longitudinal relationship between depression and baseline hs-CRP. Depression was significantly negatively associated with BMI (ρ = −0.077, p p p > 0.05). The significant relationship between CRP and depression in the underweight group suggested that not only obesity but also a low BMI could explain a substantial portion of the inflammation-depression link.

In this paper, for the solution of the continuous algebraic Riccati equation (CARE), we derived two new upper matrix bounds. Compared with the existing results, the newly obtained bounds are less conservative and more practical, which means that the condition for the existence of the upper bounds derived here is much weaker. The advantage of the results is shown by theoretical analysis and numerical examples. Moreover, in redundant optimal control, when we increase the columns of the input matrix, some sufficient conditions are presented to strictly decrease the largest singular value of the feedback matrix by utilizing these upper bounds. We also give some examples to illustrate the effectiveness of these sufficient conditions.

Background Breast cancer is recognised as a major public health problem in developing countries; however, there is very limited evidence about its epidemiology in the Central African Republic. The aim of this study was to investigate the epidemiological and histopathological characteristics of breast cancer in Bangui. Methods This is a retrospective study based on the data collected from pathological anatomy records from 2003 to 2015 in Bangui. A questionnaire was designed to collect information and data was analysed using descriptive and inferential statistical methods. Results The mean age was 45.83 (SD = 13.5) years. The age group of 45–54 years represented the majority of the study population (29.3%). Over 69.5% of the women were housewives with a moderate economic status (56.9%). Less than 14% of the study population had a level of academic degree and 85.6% lived in cities. The breast cancer prevalence was 15.27%. The age-standardized incidence and death by world population (ASW) were 11.19/100,000 and 9.97/100,000 respectively. 50–54 years were most affected. Left breast cancer is mainly common and the time between first symptoms and consultation is more than 48 months. Most (69%) of the samples analysed were lumpectomy. The most common morphology of breast cancer was invasive ductal carcinoma (64.9%). Scarff Bloom Richardson III was the main grade in both common pathological types, but their proportion showed no significant increase along with time (χ2 = 7.06, p = 0.54). Invasion of regional lymph node differed significantly among the pathological type of breast cancer (χ2 = 24.6, p = 0.02). Surgery and chemotherapy were appropriate treatment yet 84.5% of the cases died. Conclusion The findings of this study showed that breast cancer is common and mostly affected women. Epidemiological trends are more or less common to those of developing countries with a predominance of invasive ductal carcinoma. However, most of the women studied live in an urban area and developed the disease in advanced stage. The establishment of an appropriate framework will effectively contribute to promoting the early detection and reducing the incidence of this disease in the population. Electronic supplementary material The online version of this article (doi:10.1186/s12889-016-3863-6) contains supplementary material, which is available to authorized users.

This paper is concerned with the realizability problem of n-port resistive networks that contain 2n terminals. A necessary and sufficient condition for any real symmetric matrix to be realizable as the admittance of an n-port resistive network containing 2n terminals is obtained. This condition is based on the existence of a parameter matrix. Furthermore, the values of the elements are expressed in terms of the entries of the admittance matrix and the parameter matrix. Finally, a numerical example is used to illustrate the results. Copyright © 2013 John Wiley & Sons, Ltd.

Hypertension is of public health importance in China, but information on geographic distribution on hypertension by map visualization is limited for middle-aged and older adults. Regional geographic variations remain unexplained. Our study is to present geographic distributions at the provincial level and identify provinces and municipalities with high hypertension diagnosis, measurement and prevalence rates and/or low awareness, treatment, control rates among aged 45+ adults in China. We used data collected from the China Health and Retirement Longitudinal Study (n = 13,583) of Chinese people aged 45 years or older. We used weighted rates for our analysis. The rates by provinces and municipalities were compared using map visualization, and explore the main factors of the disparity using ordinal logistic regression. Higher hypertension prevalence rates (56.3%) but lower hypertension awareness, treatment and control rates (37.3%, 21.1% and 14.9%, respectively) were observed in Guizhou. Shanghai and Beijing had the highest hypertension prevalence, awareness and treatment rates (65.0%, 87.8% and 80.0% for Shanghai, 57.5%, 88.6% and 77.5% for Beijing, respectively). Remarkable variations were observed among surveyed provinces and municipalities. Several Chinese regions show particularly higher prevalence rates and/or lack of hypertension awareness and poor control.

Inspired by the computing architecture of human brain, neuromorphic computing promises massively parallel, energy efficient and fault tolerant computation compared with conventional von Neumann approaches. In order to achieve this ambitious goal, one of the crucial tasks is to make devices that can emulate the functions of biological synapses at the physical level. Here we fabricated a novel Pt/TaOx/Ta memristor with recessed Ta bottom electrodes, where the TaOx film was formed by thermal oxidation of the bottom electrode and thus had a constantly ascending concentration of oxygen vacancies from the Pt/TaOx interface to the TaOx/Ta interface. Such cell geometry and ion distribution profile gave rise to highly incremental and uniform resistive switching that emulated the potentiation or depression process of synapses. Furthermore, important synaptic learning rules, such as spike timing dependent plasticity, could also be implemented by these devices, making them well suited for electronic synapses in neuromorphic systems.

Breast cancer is the leading cause of cancer deaths among women worldwide. High breast cancer mortality has been attributed to lack of public awareness of the disease. Little is known about the level of knowledge of breast cancer in Central African Republic. This study aimed to investigate the knowledge of health professionals on breast cancer.This cross-sectional study was conducted among 158 health professionals (27 medical; 131 paramedical) in 17 hospitals in Bangui using a self-administered questionnaire. Descriptive statistical analysis, Person's χ 2 test and ANOVA were applied to examine associations between variables with0.05 being considered significant.Data analyzed using SPSS version 20 indicates that average knowledge about breast cancer perception of the entire population was 47.6%, diagnosis method 45.5%, treatment 34.3% and risk factors 23.8%. Most respondents (65.8%) agreed that breast cancer is important in the Central African Republic and that family history is a risk factor (44.3%). Clinical assessments and mammography were considered most suitable diagnostic methods, and surgery as the best treatment. The knowledge level was significantly higher among medical than paramedical staff with regard to risk factors, diagnosis and treatment. However the trainee group had very high significant differences of knowledge compared with all other groups.There is a very urgent need to update the various training programs for these professionals, with recommendations of retraining. Health authorities must create suitable structures for the overall management of cancer observed as a serious public health problem.

Due to the dynamic process of maximum power point tracking (MPPT) caused by turbulence and large rotor inertia, variable-speed wind turbines (VSWTs) cannot maintain the optimal tip speed ratio (TSR) from cut-in wind speed up to the rated speed. Therefore, in order to increase the total captured wind energy, the existing aerodynamic design for VSWT blades, which only focuses on performance improvement at a single TSR, needs to be improved to a multi-point design. In this paper, based on a closed-loop system of VSWTs, including turbulent wind, rotor, drive train and MPPT controller, the distribution of operational TSR and its description based on inflow wind energy are investigated. Moreover, a multi-point method considering the MPPT dynamic process for the aerodynamic optimization of VSWT blades is proposed. In the proposed method, the distribution of operational TSR is obtained through a dynamic simulation of the closed-loop system under a specific turbulent wind, and accordingly the multiple design TSRs and the corresponding weighting coefficients in the objective function are determined. Finally, using the blade of a National Renewable Energy Laboratory (NREL) 1.5 MW wind turbine as the baseline, the proposed method is compared with the conventional single-point optimization method using the commercial software Bladed. Simulation results verify the effectiveness of the proposed method.

Brain-inspired neuromorphic computing is expected to revolutionize the architecture of conventional digital computers and lead to a new generation of powerful computing paradigms, where memristors with analog resistive switching are considered to be potential solutions for synapses. Here we propose and demonstrate a novel approach to engineering the analog switching linearity in TaOx based memristors, that is, by homogenizing the filament growth/dissolution rate via the introduction of an ion diffusion limiting layer (DLL) at the TiN/TaOx interface. This has effectively mitigated the commonly observed two-regime conductance modulation behavior and led to more uniform filament growth (dissolution) dynamics with time, therefore significantly improving the conductance modulation linearity that is desirable in neuromorphic systems. In addition, the introduction of the DLL also served to reduce the power consumption of the memristor, and important synaptic learning rules in biological brains such as spike timing dependent plasticity were successfully implemented using these optimized devices. This study could provide general implications for continued optimizations of memristor performance for neuromorphic applications, by carefully tuning the dynamics involved in filament growth and dissolution.

Questionnaire of study. (DOCX 354Â kb)

Currently, the maximization of wind energy extraction for variable speed wind turbines (VSWT) is usually transformed into the maximum power point tracking (MPPT), i.e., the rotor speed is continuously regulated to follow the optimal rotor speed as a function of wind speed. However, it has been recognized that the increasing rotor inertia and the high fluctuation of wind speed result in the turbines’ being unable to instantly track the optimal rotor speed and tracking losses. This indicates that maximizing wind energy extraction based on MPPT is not suitable for large-inertia VSWTs under turbulence. Moreover, it is revealed and demonstrated in this letter that a conservative speed reference matching up with the slow dynamic behavior of VSWTs can effectively improve wind energy production, which provides a new approach for maximizing wind energy extraction of VSWTs under turbulence.

The active power control (APC) of variable-speed wind turbines (VSWT) is increasingly required to support the power system operation and control. Besides control strategies, the power reference also exerts a significant influence upon APC performance. Due to the VSWT instability, the optimistic reference which is usually determined according to the conventional available wind power (AWP) based on maximum power point, cannot be sustainably maintained over the dispatch period. This may results in frequent interruption of power reference tracking. On the other hand, the conservative reference will easily lead to excessive pitch regulation. In this letter, the turbine stability-constrained available wind power is defined and analyzed to sustain the power generation of scheduled wind turbines at a maximum level. Simulation results show that the VSWT dispatched according to the proposed AWP can maintain stable power generation with less pitch action and therefore better support secure and economic power system operations.