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The interfacial Dzyaloshinskii-Moriya interaction (DMI) is responsible for the emergence of topological spin textures such as skyrmions in layered structures based on metallic and insulating ferromagnetic films. However, there is active debate on where the interfacial DMI resides in magnetic insulator systems. We investigate the topological Hall effect, which is an indication of spin textures, in Tm3Fe5O12 films capped with various metals. The results reveal that Pt, W, and Au induce strong interfacial DMI and topological Hall effect, while Ta and Ti cannot. This study also provides insights into the mechanism of electrical detection of spin textures in magnetic insulator heterostructures. [ABSTRACT FROM AUTHOR]

Background: National surveys in the Kingdom of Saudi Arabia continue to show rates of breastfeeding below global recommendations. Delay of timely or early initiation of breastfeeding is common in the community. Current approaches are not addressing the major constraints. Objectives of this study were to study the pattern and determinants associated with the early and delayed initiation of breastfeeding practices among infants aged less than 24 months. Also to assess regional differences to facilitate targeted actions. Methods: This cross-sectional study was conducted from May to August 2016, based on a sample of 1700 mothers of children aged less than 24 months. The sample was randomly selected from over 165 health centers distributed across the country, at least 33 centers in each of the five geographical regions. World Health Organization standardized questionnaire for infant and young child feeding indicators was used to prepare structured questionnaire (in English translated later to Arabic) to collect the information on breastfeeding along with general sociodemographic data. Results: The breastfeeding initiation rate was 97.3% (1559/1700 mothers). Only 8.3% (141) of mothers never breastfeed their children. Early initiation of breastfeeding within 1 h of birth was 43.6% (742) among all mothers surveyed while, breastfeeding initiation rates for 1-24 h and that for more than 24 h were 27 and 21% respectively. The overall prevalence of early initiation of breastfeeding (43.6%) is considered 'fair'. Regional variation showed poor prevalence 26% (79/300 mothers) in Northern region; fair 38.4% (192/500 mothers), 45% (135/300 mothers), 49% (148/300 mothers) in the Central, Western and Eastern regions respectively; and good 63% (188/300 mothers) in the Southern region. Significant associations were indicated between early initiation of breastfeeding and mode of delivery, knowledge of the mother about the right time for early initiation, receipt of breastfeeding information, the region of residence, and educational level of the mother. Conclusion: Whilst some barriers to breastfeeding initiation manifest similarity across the regions some factors were context-specific thus, tailored interventions are imperative. Appropriate behavior change interventions, are needed attain optimal breastfeeding practices. [ABSTRACT FROM AUTHOR]

The triple active bridge (TAB) converter has been proposed to improve power density and availability in more electric aircraft applications. However, the conventional proportional-integral (PI) controller used for TAB voltage control often exhibits slow response and significant overshoot, which can impact dynamic performance. Moreover, achieving decoupling control among ports introduces computational complexity in controller design. To address these issues, this paper introduces an effective diagonal matrix decoupling strategy based on differential flatness control with single-phase shift modulation applied to a TAB converter. The proposed differential flatness control offers superior transient performance, control flexibility, and precision, ensuring compliance with DC voltage regulations while achieving optimal decoupling among ports. The comparative analysis assesses various criteria, including steady-state and dynamic performance, control complexity, and regulation and tracking properties, against PI control, unit matrix decoupling control, and the proposed differential flatness control. Hardware-in-loop (HIL) experimentation verifies the performance, confirming faster dynamic characteristics and robust port power decoupling. The results show a significant improvement in efficiency, reaching a maximum of 95.5 %, indicating reduced switching losses and enhanced overall system performance. The study concludes with a discussion on the implications of these findings and potential future research directions, such as integrating advanced optimization algorithms further to enhance the control strategy's robustness and adaptability.

DC microgrids, which use various energy sources, require an energy storage system (ESS) to stabilize the grid systems. Multiport active bridge (MAB) bidirectional DC-DC converters offer several advantages over other converters, including higher power density, bidirectional functionality, reduced component counts, soft switching ability, and a reduced number of conversion stages. However, these converters are affected by the cross-coupling effect of the control variable, with the power dissipated at each port significantly impacting the system response to step changes. This causes unstable DC bus voltage, slow dynamic response, large overshoot, and limits its reliability. To address this issue, a power decoupling with feedforward compensation based on model predictive control (MPC) and fuzzy compensation control (FCC) was developed. The proposed control strategy can achieve good transient performance (lower settling time, overshoot/undershoot in the controlled variables), excellent decoupling control performance, and high control flexibility with good precision to comply with DC voltage regulations. This article investigates the PD-MPC-FCC and its implementation in a triple active bridge (TAB) converter with multi-winding high-frequency transformers. The proposed MPC-FFC integrates MPC with fuzzy compensation control. The MPC aims to obtain more precise current reference values and implement current feedforward control to stabilize the DC bus voltage, while the FCC adaptively compensates for steady-state voltage errors. A hardware-in-the-loop (HIL) experimental case study using Typhoon 602 validates the TAB converter’s performance with the proposed PD-MPC-FCC strategy. Additionally, a comparison with previous works confirms the effectiveness of the proposed method. The HIL experimental setup and comparative analysis results demonstrate that the proposed method is effective, providing faster dynamic characteristics and port power decoupling operation capability.

Uncertain weather scenarios have an impact on the output of solar farms and therefore affect the security of the grid. It is advantageous for power system operators to forecast solar energy to balance the load generation and for optimal power scheduling. The most promising deep-learning techniques to combine weather variables with precise measurements of solar irradiance are not widely discussed. To close this research gap and produce better prediction results, this article aims to formulate and compare two distinctive deep learning algorithms for using time series forecasting approaches to predict solar irradiance. For multivariate data, the forecasting technique Bi-Directional Long Short-Term Memory (BiLSTM), and BiLSTM-GRU (Gated Recurrent Unit) Dropout, are examined in this study. The output results from the proposed model are compared with other benchmark models based on performance error measurements, including Mean Absolute Error (MAE), Root Mean Square Error (RMSE), Coefficient of Determination (R2) and Mean Absolute Percentage Error (MAPE). It was found that the proposed hybrid method, BiLSTM-GRU with dropout outperformed the other methods in terms of solar irradiance predicting accuracy. The analysis presented the best RMSE of 1.55 and MAE of 1.13 for BiLSTM and RMSE of 1.40 and MAE of 0.91 for BiLSTM-GRU architecture using hyperparameter tuning. The comparison results show that the prediction accuracy is improved by tuning the hyperparameters. [ABSTRACT FROM AUTHOR]

The aim of this work is to study the effect of the addition of nickel oxide nanoparticles in different concentrations to the polymer matrix of polyvinylpyrrolidone on the electrical and optical properties of the membrane. Nickel oxide nanoparticles were prepared by the hydrothermal method, and the nanoscale size of the particles was measured by scanning field emissions (SEM). To find out the crystal size, X-ray diffractivity (XRD) was carried out. the chemical bonds of composite membranes were determined by infrared spectroscopy (IR) examination .where the Ni-O bond appeared at wavenumber 408cm-1. The energy gap was calculated for the pure polymer and the composite polymer, and there was a decrease. The Hall Effect test was performed to measure the electrical properties of the composite and pure membrane and the results showed that the best conductivity For a composite membrane, at the nickel concentration (0.1) in the polymer matrix. As a result, a composite thin film of PVP-NiO NPs can be utilized as a semi-conductor in photo sensor and solar cell applications.

Abstract Despite advances in diagnosis, surgery, and antimicrobial therapy, mortality rates associated with complicated intra-abdominal infections remain exceedingly high. The 2013 update of the World Society of Emergency Surgery (WSES) guidelines for the management of intra-abdominal infections contains evidence-based recommendations for management of patients with intra-abdominal infections.

Recently, the Modular Multilevel Converter (MMC) has drawn significant attention due to its diverse merits and its applicability to a wide range of medium to high-power applications. The growing interest in the MMC can be attributed to its attractive features such as modularity, reliability, and high voltage capability. Significant research has been conducted on the MMC over the last few years to develop its operation and control in various applications. However, the application of MMCs in microgrids remains a largely unexplored topic. Therefore, this paper aims to address this research gap by offering an in-depth review of the latest developments concerning circuit topologies, control schemes, and fault-tolerance strategies of MMC within microgrid applications. This comprehensive review not only provides a synthesized overview of the current state of the art but also paves the way for future investigations in this promising field. The outcomes from this study are expected to stimulate further advancements in MMC applications in microgrid systems, thus contributing to the continuous improvement and evolution of microgrids.

Layered Zintl phase van der Waals (vdW) materials are of interest due to their strong spin-orbit coupling and potential for high mobility. Here, we report the successful growth of large area CaGe 2 films, as a model of layered Zintl phase materials, on atomically flat Ge(111) substrates by molecular beam epitaxy (MBE) using an alternating layer growth (ALG) protocol. Reflection high energy electron diffraction (RHEED) patterns of the Ge buffer layer and CaGe 2 indicate high quality two dimensional surfaces, which is further confirmed by atomic force microscopy (AFM), showing atomically flat and uniform CaGe 2 films. The appearance of Laue oscillations in X-ray diffraction (XRD) and Kiessig fringes in the X-ray reflectivity (XRR), which are absent in co-deposited CaGe 2 , confirms the uniformity of the CaGe 2 film and the smoothness of the interface. These results demonstrate a novel method of deposition of CaGe 2 that could be also applied to other layered Zintl phase vdW materials. Also, the high quality of the CaGe 2 film is promising for the exploration of novel properties of germanane. [ABSTRACT FROM AUTHOR]

This paper will discuss how the design and discourse of transitional justice mechanisms- which include and take into account the views and needs of civil society and affected communities- boost the legitimacy of the transitional process and the prospects for reconciliation. This process could be described as the politics of transitional justice mechanisms from below. The paper will focus on the Somaliland situation as a case study. The paper will explain both the Somaliland alternative dispute resolution (ADR) mechanism and transitional justice as well as analyze in detail how the indigenous ADR mechanism has been used as tool for political transitional justice during the reconciliation period. Lessons learned from the Somaliland reconciliation process will be briefly explained and some critiques and pitfalls of transitional justice in Somaliland will be raised. Finally, the paper will conclude with some recommendations and observations about the usefulness of the traditional and indigenous ADR systems as reference examples for political transitional justice in similar situations around the world. [ABSTRACT FROM AUTHOR]

This study offers a thorough examination of the zero voltage switching (ZVS) operation range and deadband conditions for a bidirectional DC-DC converter with phase shift control, featuring dual H-bridge. The analysis considers the soft switching range of the DAB converter, accounting for the impact of the headband and the ZVS capacitor. By applying the differential equation of the circuit during deadband time, a sufficient constraint for the input and output bridges can be calculated. The findings indicate that as the output voltage increases, the minimum phase shift value required to achieve ZVS decreases, and expanding the phase shift value will expand the ZVS range and reduce switching losses. The study provides simulation results for various operating conditions, validating the theoretical analysis of the proposed system. In addition, the results furnish information about the circuit behavior during the deadband and waveforms. Finally, MATLAB/SIMULINK verifies the simulation results for different operating stages.

Background Rapid diagnostic and prognostic tests for coronavirus disease (COVID-19) are urgently required. We aimed to evaluate the diagnostic and prognostic ability of breath analysis using gas chromatography–ion mobility spectrometry (GC-IMS) in hospitalized patients with COVID-19. Methods Between February and May 2021, we took 1 breath sample for analysis using GC-IMS from participants who were admitted to the hospital for COVID-19, participants who were admitted to the hospital for other respiratory infections, and symptom-free controls, at the University Hospitals of Leicester NHS Trust, United Kingdom. Demographic, clinical, and radiological data, including requirement for continuous positive airway pressure (CPAP) ventilation as a marker for severe disease in the COVID-19 group, were collected. Results A total of 113 participants were recruited into the study. Seventy-two (64%) were diagnosed with COVID-19, 20 (18%) were diagnosed with another respiratory infection, and 21 (19%) were healthy controls. Differentiation between participants with COVID-19 and those with other respiratory tract infections with GC-IMS was highly accurate (sensitivity/specificity, 0.80/0.88; area under the receiver operating characteristics curve [AUROC], 0.85; 95% CI, 0.74–0.96). GC-IMS was also moderately accurate at identifying those who subsequently required CPAP (sensitivity/specificity, 0.62/0.80; AUROC, 0.70; 95% CI, 0.53–0.87). Conclusions GC-IMS shows promise as both a diagnostic tool and a predictor of prognosis in hospitalized patients with COVID-19 and should be assessed further in larger studies. [ABSTRACT FROM AUTHOR]

In this work, a voltage regulation scheme to stabilize voltage variation in the consumer side is proposed. The voltage regulation scheme uses IGBT-based onload tap changer (OLTC) and nonlinear hysteresis control algorithm. The proposed switching algorithm establishes the commutation of the taps without redundant short circuit operation of the taps. The experimental results of the designed system show accurate voltage regulation at the consumer side and high ability of the designed system to fix voltage sag and voltage swell in maximum of one cycle period. The paper considers the consequences of fault in the drive circuit of the IGBT tap changer and discusses its reliability. The analysis and the experimental results of the faults in the drive circuit show that the loss of one drive signal results in a large circulating DC current in the primary circuit and may result in fault current of value more than three times the operated current, which leads to unavailability of the system.

Experimental data on the effects of cleavers (Galium aparine) and yarrow (Achillea millefolium) extracts on rumen microbial fermentation are scarce. The objective of this study was to determine the effects of cleavers and yarrow extracts on in vitro ruminal fermentation. Incubation trial was carried out using the long-term rumen simulation technique (RUSITEC). The experiment lasted 10 days. After an adaptation period of 5 days, the fermentation vessels divided into 3 groups; first three vessels received no additives (control), second three vessels received 500 mg/L cleavers extract daily, and third three vessels received 500 mg/L yarrow extract daily. Supplementations of cleavers and yarrow extracts had no significant effect on ruminal pH, total volatile fatty acids (VFA), acetate, propionate and methane production, NH3-N concentration and, total protozoa. However, both extracts decreased dry matter digestibility (DMD) (P

The fruits, leaves, and bark of the guava (Psidium guajava) tree have traditionally been used to treat a myriad of ailments, especially in the tropical and subtropical regions. The various parts of the plant have been shown to exhibit medicinal properties, such as antimicrobial, antioxidant, anti-inflammatory, and antidiabetic activities. Recent studies have shown that the bioactive phytochemicals of several parts of the P. guajava plant exhibit anticancer activity. This review aims to present a concise summary of the in vitro and in vivo studies investigating the anticancer activity of the plant against various human cancer cell lines and animal models, including the identified phytochemicals that contributes to their activity via the different mechanisms. In vitro growth and cell viability studies, such as the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, the sulforhodamine B (SRB) assay, and the trypan blue exclusion test, were conducted using P. guajava extracts and their biomolecules to assess their effects on human cancer cell lines. Numerous studies have showcased that the P. guajava plant and its bioactive molecules, especially those extracted from its leaves, selectively suppress the growth of human cancer cells without cytotoxicity against the normal cells. This review presents the potential of the extracts of P. guajava and the bioactive molecules derived from it, to be utilized as a feasible alternative or adjuvant treatment for human cancers. The availability of the plant also contributes towards its viability as a cancer treatment in developing countries.

This paper presents a new topology of clamped diode multilevel DC/DC buck power converter for a DC motor system. The proposed converter circuit consists of four cascaded MOSFET power switches with three clamping diodes and four voltage sources (voltage cells) connected in series. The main objective of the new topology is to reduce current ripples and torque ripples that are associated with hard switching of the traditional chopper circuit. When the voltage profile of this converter is applied on a DC motor, it positively affects the performance of the DC motor armature current and the generated dynamic torque. The output voltage of the proposed topology shows an adequate performance for tracking of reference voltage with small ripples that are normally reflected into smaller EMI noise. Moreover, it has been shown that the operation of the DC motor with the newly proposed chopper topology greatly decreases the motor armature current ripples and torque ripples by a factor equal to the number of the connected voltage cells. Both simulation and experimental results on a prototype of a DC motor are provided to validate the proposed chopper topology. The results prove that the mechanical vibration and acoustic noises have also been reduced roughly by 13 dBs with a continuous variable input voltage pattern.

This paper introduces a new operational scheme for several multilevel (five-level diode-clamped) inverters in the microgrid. The presented operational scheme has a central structure (different from the distributed controllers for droop schemes) to alleviate the drawback of the conventional droop control for microgrid operation. The contribution of this paper is focused on the suggested operational scheme, which has two contributory components. The first component is the novel smooth variable structure filters (SVSF), which are formulated to estimate the disturbances of voltage harmonics and voltage unbalance. The second component is an efficient adaptive sliding mode controller to operate these inverters. This proposed operational achieves equal power sharing among working inverters, compensating for voltage unbalance at the point of common coupling (PCC) at loads, and mitigation for voltage harmonics at the PCC. More importantly, the propounded operational scheme efficiently stabilizes voltage with the variation of balanced, unbalanced, and non-linear loads in addition to the seamless transient and steady-state performance for injected power by inverters. The performance of the suggested operational scheme is justified by simulation results.