Evaluation of isolated DC/DC converter topologies for future HVDC aerospace microgrids

High performance power conversion equipment is currently gaining an increasing interest for aircraft applications. In particular, isolated bidirectional DC/DC converters are often proposed for modern HVDC aircraft distribution systems. For such reason an evaluation of several isolated DC/DC converter topology is carried out considering the proposed application, interfacing a 270V DC network with a 28V DC network. A trade off evaluation has been carried out for three different topologies and an experimental prototype has been manufactured for the selected conversion architecture. Simulation and experimental results are provided in order to validate the trade off and the design of the proposed converter

Model Predictive Control for Dual Active Bridge in Naval DC Microgrids Supplying Pulsed Power Loads Featuring Fast Transition and Online Transformer Current Minimization

Pulsed power loads (PPLs) are commonly incorporated in medium voltage dc microgrids on naval vessels. To mitigate their detrimental effects, dedicated energy storage systems can be installed and their converters need to have excellent disturbance rejection capability. To facilitate this objective, a moving-discretized-control-set model-predictive-control (MDCS-MPC) is proposed in this letter and applied on a dual-active-bridge converter. Fixed switching frequency is maintained, enabling easy passive components design. The proposed MDCS-MPC has a small number of calculating points in each switching period, which enables the implementation in standard commercial control platforms. The operating principle of the MDCS-MPC is introduced in development of a cost function that, on one hand, provides stiff voltage regulation; on the other hand, minimizes transformer current stress online. Theoretical claims are verified on a 20 kHz 1 kW dual active bridge

Evaluation of isolated DCDC converter topologies for future HVDC aerospace microgrids

High performance power conversion equipment is currently gaining an increasing interest for aircraft applications. In particular, isolated bidirectional DC/DC converters are often proposed for modern HVDC aircraft distribution systems. For such reason an evaluation of several isolated DC/DC converter topology is carried out considering the proposed application, interfacing a 270V DC network with a 28V DC network. A trade off evaluation has been carried out for three different topologies and an experimental prototype has been manufactured for the selected conversion architecture. Simulation and experimental results are provided in order to validate the trade off and the design of the proposed converter

Ultrasound Versus Contrast-Enhanced Magnetic Resonance Imaging for Subclinical Synovitis and Tenosynovitis: A Diagnostic Performance Study

OBJECTIVES: Radiographic manifestations of synovitis (e.g., erosions) can be observed only in the late stage of rheumatoid arthritis. Ultrasound is a noninvasive, cheap, and widely available technique that enables the evaluation of inflammatory changes in the peripheral joint. In the same way, dynamic contrast-enhanced magnetic resonance imaging (MRI) enables qualitative and quantitative measurements. The objectives of the study were to compare the sensitivity and accuracy of ultrasound in detecting subclinical synovitis and tenosynovitis with those of contrast-enhanced MRI. METHODS: The ultrasonography and contrast-enhanced MRI findings of the wrist, metacarpophalangeal, and proximal interphalangeal joints (n=450) of 75 patients with a history of joint pain and morning stiffness between 6 weeks and 2 years were reviewed. The benefits score was evaluated for each modality. RESULTS: The ultrasonic findings showed inflammation in 346 (77%) joints, while contrast-enhanced MRI found signs of early rheumatoid arthritis in 372 (83%) joints. The sensitivities of ultrasound and contrast-enhanced MRI were 0.795 and 0.855, respectively, and the accuracies were 0.769 and 0.823, respectively. Contrast-enhanced MRI had a likelihood of 0–0.83 and ultrasound had a likelihood of 0–0.77 for detecting synovitis and tenosynovitis at one time. The two imaging modalities were equally competitive for detecting synovitis and tenosynovitis (p=0.055). CONCLUSION: Ultrasound could be as sensitive and specific as contrast-enhanced MRI for the diagnosis of subclinical synovitis and tenosynovitis

Model-Predictive-Control for Dual-Active-Bridge Converters Supplying Pulsed Power Loads in Naval DC Micro-grids

Pulsed-Power-Loads (PPLs) are becoming prevalent in medium-voltage naval DC micro-grids. To alleviate their effects on the system, energy storages are commonly installed. For optimal performance, their interface converters need to have fast dynamics and excellent disturbance rejection capability. Moreover, these converters often need to have voltage transformation and galvanic isolation capability since common energy storage technologies like batteries and super-caps are typically assembled with low voltage strings. In order to address these issues, a Moving-Discretized-Control-Set Model-Predictive-Control (MDCS-MPC) is proposed in this paper and applied on a Dual-Active-Bridge converter. Fixed switching frequency is maintained, enabling easy passive components design. The proposed MDCS-MPC has a reduced prediction horizon, which allows low computational burden. The operating principle of the MDCS-MPC is introduced in development of a cost function that provides stiff voltage regulation. Resonance damping and sampling noise resistance can also be achieved with the proposed cost function. An adaptive step is introduced to enable fast transition. Assessments on the performance of the proposed MDCS-MPC are conducted. Comparisons with other control methods are also provided. Experimental validations on a 300V/300V 20kHz 1kW Dual-Active-Bridge converter are carried out to verify the theoretical claims. Index Terms-Isolated DC/DC converter, Dual-Active-Bridge (DAB), Model Predictive Control (MPC)

Paliperidone long-acting injection in the treatment of an adolescent with schizophrenia with fluctuating mental symptoms during menstrual period: a case report

BackgroundThe treatment of schizophrenia, a chronic disabling psychiatric disorder, mainly relies on antipsychotics to control the disease and improve clinical symptoms. Various medication options are available, and differences in treatment effects, even for the same medication, have been noted. Treatment efficacy is correlated with the patient’s sex, age, and physical condition. When a drug fails to achieve the desired effect or the symptoms are unstable, the drug dose is often increased or a change in medication is advised according to the patient’s situation.Case presentationWe report the case of a 16 years-old girl with schizophrenia and apparent psychotic symptoms. According to the genetic testing results, the symptoms were effectively controlled, and she was discharged from the hospital with the prescription of paliperidone sustained-release tablets. During the follow-up, her symptoms fluctuated during menstrual period, causing her great distress. Furthermore, her compliance gradually declined during the following 2 years of treatment, and the medication was often discontinued. We changed the drug from an oral tablet to an injection preparation while maintaining the active ingredients of the drug. The patient’s symptoms were significantly controlled, and no fluctuation of symptoms occurred during the menstrual cycle.ConclusionLong-acting antipsychotic injections can be administered to female adolescents with schizophrenia who experience fluctuating psychotic symptoms during menstruation. This technique can ensure both consistency of medication and improvement in clinical symptoms

Characterization of the Small RNA Transcriptomes of Androgen Dependent and Independent Prostate Cancer Cell Line by Deep Sequencing

Given the important roles of miRNA in post-transcriptional regulation and its implications for cancer, characterization of miRNA facilitates us to uncover molecular mechanisms underlying the progression of androgen-independent prostate cancer (PCa). The emergence of next-generation sequencing technologies has dramatically changed the speed of all aspects of sequencing in a rapid and cost-effective fashion, which can permit an unbiased, quantitive and in-depth investigation of small RNA transcriptome. In this study, we used high-throughput Illumina sequencing to comprehensively represent the full complement of individual small RNA and to characterize miRNA expression profiles in both the androgen dependent and independent Pca cell line. At least 83 miRNAs are significantly differentially expressed, of which 41 are up-regulated and 42 are down-regulated, indicating these miRNAs may be involved in the transition of LNCaP to an androgen-independent phenotype. In addition, we have identified 43 novel miRNAs from the androgen dependent and independent PCa library and 3 of them are specific to the androgen-independent PCa. Function annotation of target genes indicated that most of these differentially expressed miRNAs tend to target genes involved in signal transduction and cell communication, epically the MAPK signaling pathway. The small RNA transcriptomes obtained in this study provide considerable insights into a better understanding of the expression and function of small RNAs in the development of androgen-independent prostate cancer