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51.
BPA is one of the most common endocrine disruptors that is widely being manufactured daily nationwide. Although scientific evidence supports claims of negative effects of BPA on humans, there is also evidence suggesting that a low level of BPA is safe. However, numerous in vivo trials contraindicate with this claim and there is a high possibility of BPA exposure could lead to obesity. It has been speculated that this does not stop with the exposed subjects only, but may also cause transgenerational effects. Direct disruption of endocrine regulation, neuroimmune and signaling pathways, as well as gut microbiata, has been identified to be interrupted by BPA exposure, leading to overweight or obesity. In these instances, cardiovascular complications are one of the primary notable clinical signs. In regard to this claim, this review paper discusses the role of BPA on obesity in the perspective of endocrine disruptions and possible cardiovascular complications that may arise due to BPA. Thus, the aim of this review is to outline the changes in gut microbiota and neuroimmune or signaling mechanisms involved in obesity in relation to BPA. To identify potentially relevant articles, a depth search was done on the databases Nature, PubMed, Wiley Online Library, and Medline & Ovid from the past 5 years. According to Boolean operator guideline, selected keywords such as (1) BPA OR environmental chemical AND fat OR LDL OR obese AND transgenerational effects or phenocopy (2) Endocrine disruptors OR chemical AND lipodystrophy AND phenocopy (3) Lipid profile OR weight changes AND cardiovascular effect (4) BPA AND neuroimmune OR gene signaling, were used as search terms. Upon screening, 11 articles were finalized to be further reviewed and data extraction tables containing information on (1) the type of animal model (2) duration and dosage of BPA exposure (3) changes in the lipid profile or weight (4) genes, signaling mechanism, or any neuroimmune signal involved, and (5) transgenerational effects were created. In toto, the study indicates there are high chances of BPA exposure affecting lipid profile and gene associated with lipolysis, leading to obesity. Therefore, this scoping review recapitulates the possible effects of BPA that may lead to obesity with the evidence of current in vivo trials. The biomarkers, safety concerns, recommended dosage, and the impact of COVID-19 on BPA are also briefly described.  相似文献   
52.
This paper aims to develop a robust decomposed system control (RDSC) strategy under input constraints for an electro-mechanical linear actuator (EMLA) facing model uncertainty and external disturbances. At first, a state-space model of a complex multi-stage gearbox EMLA system, driven by a permanent magnet synchronous motor (PMSM), is developed, and the non-ideal characteristics of the ball screw are presented through the model. The result is a four-order nonlinear strict-feedback form (NSFF) system decomposed into three subsystems. As the paper's main result, a novel RDSC strategy with uniform exponential stability for controlling subsystem states is presented. This developed controller avoids the "explosion of complexity" problem associated with backstepping by treating the time derivative of the virtual control input as an uncertain system term. The proposed method, despite assuming load disturbances and input constraints with arbitrary bounds, offers a straightforward control approach for a broader range of applications. Further, the controller's performance is evaluated by simulating two distinct duty cycles, each representing different levels of demand on the actuator facing load disturbances near the rated motor performance.  相似文献   
53.
54.
Effect of annealing temperature on the characteristics of sol–gel-driven Ta ax La(1?a)x O y thin film spin-coated on Si substrate as a high-k gate dielectric was studied. Ta ax La(1?a)x O y thin films with different amounts of a were prepared (as-prepared samples). X-ray diffraction measurements of the as-prepared samples indicated that Ta0.3x La0.7x Oy film had an amorphous structure. Therefore, Ta0.3x La0.7x O y film was chosen to continue the present studies. The morphology of Ta0.3x La0.7x O y films was studied using scanning electron microscopy and atomic force microscopy techniques. The obtained results showed that the size of grain boundaries on Ta0.3x La0.7x O y film surfaces was increased with increasing annealing temperature. Electrical and optical characterizations of the as-prepared and annealed films were investigated as a function of annealing temperature using capacitance–voltage (CV) and current density–voltage (JV) measurements and the Tauc method. The obtained results demonstrated that Ta0.3x La0.7x O y films had high dielectric constant (≈27), wide band gap (≈4.5 eV), and low leakage current density (≈10?6 A/cm2 at 1 V).  相似文献   
55.
In this paper, a two‐phase algorithm for the spectrum sensing and power/rate control of a secondary user (S‐user) or cognitive radio is proposed. In the first phase, the primary base station (P‐BS), which is conscious of both the number and the data rate of primary active users (P‐user), broadcasts theitusage capacity percentage (UCP) of its cell. Since knowing only the UCP is not enough to guarantee that the total load (of P‐users and S‐users) is less than a maximum permissible load, the S‐user must measure the total interference received from both the P‐users and other S‐users. In this direction, using both the UCP and measurement of the interference received from the P‐users and the S‐users by the S‐user or secondary base station (S‐BS), we mathematically derive an equation for issuing data transmission permission, which if it is held then the second phase of the algorithm: the transmit power/rate control starts. In this phase, the S‐user and the S‐BS look for feasible values for the transmit power level and transmission rate. If there are feasible values, it starts its transmission at these feasible transmit power and rate. Since both the location of the S‐user and the channel condition vary in time, the whole algorithm is iterated periodically with a period faster than the coherence time of the channel. Furthermore, we consider the down link of the above system with cooperation among neighboring S‐users to overcome fading channels and we investigate the amount of improvement in the reliability of the issuing data transmission permission. As well, we consider the uplink of the system with multiple antennas in the S‐BS to investigate the improvement in the same parameter over spatially correlated and independent fading channels. Theoretical analysis is validated using computer simulations. Both theoretical analysis and computer simulations show that the proposed cooperative spectrum sensing algorithm performs properly at SNR = ?5dB in flat Nakagami‐m fading channels with m = 1 even in correlated fading channels. We also address the improvement of the reliability of the issuing data transmission permission in the uplink in case of using multiple antennas only in the S‐BS. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   
56.
Adaptive beamformers are designed with the aim of detection of noise and intentional destructive interference and then removing them from the desired signal. This is done by placing high attenuation in the direction of the destructive signal in the radiation pattern of antenna arrays without attenuating the signal from a known direction. Minimum variance distortionless response and linearly constrained minimum variance are among such algorithms in mobile communications. A short explanation of the theory and weights formulae of these beamformers will be given. Two designs for weights calculations in Simulink with the added library of DSP-Builder tool from Altera will be presented. Quadrature Rectangular decomposition with Modified Gram-Schmidt algorithm is used instead of the direct matrix inversion. All calculations are done in single floating point mode for the required high accuracy. Modelsim has been used for hardware simulation and measuring the required clock cycles. The target FPGA is Aria10 from Altera which has floating point DSP blocks for high-performance computations. Hardware resources usage, power consumption, maximum clock frequency and update rate for different matrix sizes of these two beamformers are compared and discussed. The results are also compared with some other relevant reported works.  相似文献   
57.
In the current trend in telecommunications industry towards all‐internet‐protocol (IP) infrastructures, IP multimedia subsystem (IMS) plays a critical role by providing a coherent data and control‐plane solution for large‐scale live multimedia applications in a flexible and cost‐effective manner. On the other hand, such a large‐scale service platform would inevitably fail without effective support for the quality‐of‐service (QoS) requirements perceived by its users. Among the most important factors that influence user QoS are system performance and scalability. In this paper, a performance model for IMS systems is developed using the queueing Petri nets (QPNs) as the modeling formalism. The model's parameters are tuned based on the measurements carried out using a well‐known IMS implementation. The model is validated against the real system. During the model calibration, the Java garbage‐collector process used in the home subscriber‐server (HSS) implementation was found to be a main factor in the discrepancy between the model and the reality. In addition, the effects of other factors such as the network stack in the operating system are investigated. The validated model is employed to give insights into the scalability of every single instance of IMS implementation. The model is extended to study load balancing among multiple instances of HSS to remove the main bottleneck in the system. It provides a valuable platform for resource management of various components of the IMS ecosystem to support the intended level of QoS for the users.  相似文献   
58.
A numerical simple, accurate and precise method based on spectrophotometric data coupled with multivariate calibration methods, PLS and MLR, combined with GA was developed for the simultaneous determination of two benzodiazepines, Clobazam and Flurazepam. A data set of absorption spectra obtained from a calibration set of mixtures containing the compounds was used to build GA-PLS and GA-MLR models. The models were tested using a dataset constructed from the compound synthetic solutions. The better model was also applied to plasma samples. The proposed method requires no preliminary separation steps and can be used for these drugs analysis in quality control laboratories.  相似文献   
59.
As a service to readers who understand German, French or Spanish better than English, the abstract for the research article in this issue follow in these languages.  相似文献   
60.
The tribological responses of palm oil and soybean oil, combined with two commercial antiwear additives (zinc dialkyl dithiophosphate and boron compound), were investigated at a lubricant temperature of 100°C and under severe contact conditions in a reciprocating sliding contact. The friction coefficient of palm oil with zinc dialkyl dithiophosphate was closest to the commercial mineral engine oil, with a 2% difference. The soybean oil with zinc dialkyl dithiophosphate produced a 57% improvement in wear resistance compared to its pure oil state. The existence of boron nitride in vegetable oils was only responsive in reduction of wear rather than friction. The response of commercial antiwear additives with vegetable oils showed a potential for the future improvement in the performance of vegetable oils.  相似文献   
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