A method for the suppression of fluctuations in the neutral-point potential of a three-level NPC inverter with a capacitor-voltage loop

This paper investigates the problem of fluctuation of the neutral-point potential (NPP) in a three-level NPC inverter with a capacitor-voltage loop. The phase pulse width duty cycle disturbance PWM method is proposed to suppress the NPP fluctuation efficiently. Based on the basic carrier-based Phase Disposition (PD) PWM method, the average pulse neutral-point current model is established. Then the frequency, amplitude and equivalent initial phase of the NPP fluctuation are analyzed based on the current model. According to the alternating error of the DC-link capacitor voltages, a capacitor-voltage loop with a quasi PR (proportional resonant) controller is presented. The control variable, which varies with the modulation index, phase current, load power factor, etc, can be obtained from the quasi PR controller. Finally, an experimental three-level NPC inverter is described and the validity and feasibility of the proposed method are verified by experimental results

Učinak glicerola i glukoze na povećanje biomase, udjela lipida i topljivih ugljikohidrata u miksotrofnoj kulturi alge Chlorella vulgaris

Biodiesel-derived glycerol is a promising substrate for mixotrophic cultivation of oleaginous microalgae, which can also reduce the cost of microalgal biodiesel. The objective of this study is to investigate the potential of using glycerol and glucose as a complex carbon substrate to produce microalgal biomass and biochemical components, such as photosynthetic pigments, lipids, soluble carbohydrates and proteins by Chlorella vulgaris. The results show that C. vulgaris can utilize glycerol as a sole carbon substrate, but its effect is inferior to that of the mixture of glycerol and glucose. The effect of glycerol and glucose could enhance the algal cell growth rate, biomass content and volumetric productivity, and overcome the lower biomass production on glycerol as the sole organic carbon source in mixotrophic culture medium. The utilization of complex organic carbon substrate can stimulate the biosynthesis of lipids and soluble carbohydrates as the raw materials for biodiesel and bioethanol production, and reduce the anabolism of photosynthetic pigments and proteins. This study provides a promising niche for reducing the overall cost of biodiesel and bioethanol production from microalgae as it investigates the by-products of algal biodiesel production and algal cell hydrolysis as possible raw materials (lipids and carbohydrates) and organic carbon substrates (soluble carbohydrates and glycerol) for mixotrophic cultivation of microalgae.Glicerol dobiven iz biodizela može se upotrijebiti za uzgoj miksotrofnih mikroalgi iz kojih se proizvodi ulje, te za smanjenje troškova proizvodnje biodizela. Svrha je ovoga rada bila ispitati mogućnost primjene glicerola i glukoze u složenoj hranjivoj podlozi za uzgoj alge Chlorella vulgaris, te proizvodnju biomase i biokemijskih sastojaka, kao što su fotosintetski pigmenti, lipidi, topljivi ugljikohidrati i proteini. Rezultati potvrđuju da se alga Chlorella vulgaris može uzgojiti na glicerolu kao jedinom izvoru ugljika, iako su bolji rezultati postignuti uzgojem na podlozi s glicerolom i glukozom. Stopa rasta, prinos biomase i volumetrijska produktivnost alge povećani su primjenom podloge s glicerolom i glukozom, u usporedbi s podlogom koja sadržava samo glukozu kao organski izvor ugljika. Uporabom složene hranjive podloge može se ubrzati biosinteza lipida i topljivih ugljikohidrata (sirovina za proizvodnju biodizela i bioetanola), te usporiti sinteza fotosintetskih pigmenata i proteina. U radu je ispitana mogućnost primjene nusproizvoda dobivenih proizvodnjom biodizela i hidrolizom algi te podloga s organskim izvorima ugljika (topljivi ugljikohidrati i glicerol) kao sirovina (izvor lipida i ugljikohidrata) za proizvodnju miksotrofnih mikroalgi, radi smanjenja ukupnih troškova proizvodnje biodizela i bioetanola

An adaptive working state iterative calculation method of the power battery by using the improved Kalman filtering algorithm and considering the relaxation effect.

The battery modeling and iterative state calculation in the battery management system is very important for the high-power lithium-ion battery packs, the accuracy of which affects its working performance and safety. An adaptive improved unscented Kalman filtering algorithm is developed to realize the iterative calculation process, aiming to overcome the rounding error in the numerical calculation treatment when it is used to estimate the nonlinear state value of the battery pack. As the sigma point is sampled in the unscented transform round from the unscented Kalman filter algorithm, an imaginary number appears that results in the working state estimation failure. In order to solve this problem, the decomposition is combined with the calculation process. Meanwhile, an adaptive noise covariance matching method is implied. Experiments show that the proposed method can guarantee the semi-positive and numerical stability of the state covariance, and the estimation accuracy can reach the third-order precision. The estimation error remains 1.60% under the drastic voltage and current change conditions, which can reduce the estimation error by 1.00% compared with the traditional method. It can provide a theoretical safety protection basis of the energy management for the lithium-ion battery pack

Novel frataxin isoforms may contribute to the pathological mechanism of friedreich ataxia

This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.Friedreich ataxia (FRDA) is an inherited neurodegenerative disease caused by frataxin (FXN) deficiency. The nervous system and heart are the most severely affected tissues. However, highly mitochondria-dependent tissues, such as kidney and liver, are not obviously affected, although the abundance of FXN is normally high in these tissues. In this study we have revealed two novel FXN isoforms (II and III), which are specifically expressed in affected cerebellum and heart tissues, respectively, and are functional in vitro and in vivo. Increasing the abundance of the heart-specific isoform III significantly increased the mitochondrial aconitase activity, while over-expression of the cerebellum-specific isoform II protected against oxidative damage of Fe-S cluster-containing aconitase. Further, we observed that the protein level of isoform III decreased in FRDA patient heart, while the mRNA level of isoform II decreased more in FRDA patient cerebellum compared to total FXN mRNA. Our novel findings are highly relevant to understanding the mechanism of tissue-specific pathology in FRDA.This work was supported by the intramural program of the National Institute of Child Health and Human Development, National Institutes of Health, and in part by Friedreich ataxia research association; by the National Nature Science Foundation of China (NSFC) (No. 31071085), by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry, and by State Key Laboratory of Pharmaceutical Biotechnology (No. ZZYJ-SN-201006). Zvonimir Marelja was supported by a grant from the Studienstiftung des Deutschen Volkes and by Deutscher Akademischer Austauschdienst scholarship. Additional support was obtained from the Deutsche Forschungsgemeinschaft Grant SL1171/5-3

Cell-Cycle-Regulated Interaction between Mcm10 and Double Hexameric Mcm2-7 Is Required for Helicase Splitting and Activation during S Phase

Mcm2-7 helicase is loaded onto double-stranded origin DNA as an inactive double hexamer (DH) in G1 phase. The mechanisms of Mcm2-7 remodeling that trigger helicase activation in S phase remain unknown. Here, we develop an approach to detect and purify the endogenous DHs directly. Through cellular fractionation, we provide in vivo evidence that DHs are assembled on chromatin in G1 phase and separated during S phase. Interestingly, Mcm10, a robust MCM interactor, co-purifies exclusively with the DHs in the context of chromatin. Deletion of the main interaction domain, Mcm10 C terminus, causes growth and S phase defects, which can be suppressed through Mcm10-MCM fusions. By monitoring the dynamics of MCM DHs, we show a significant delay in DH dissolution during S phase in the Mcm10-MCM interaction-deficient mutants. Therefore, we propose an essential role for Mcm10 in Mcm2-7 remodeling through formation of a cell-cycle-regulated supercomplex with DHs

Visualization of ultrasonic wave field by stroboscopic polarization selective imaging

A stroboscopic method based on polarization selective imaging is proposed for dynamic visualization of ultrasonic waves propagating in a transparent medium. Multiple independent polarization parametric images were obtained, which enabled quantitative evaluation of the distribution of the ultrasonic pressure in quartz. In addition to the detection of optical phase differences δ in conventional photo-elastic techniques, the azimuthal angle φ and the Stokes parameter S2 of the polarized light are found to be highly sensitive to the wave-induced refraction index distribution, opening a new window on ultrasonic field visualization

Ginseng-Angelica-Sansheng-Pulvis Boosts Neurogenesis Against Focal Cerebral Ischemia-Induced Neurological Deficiency

BackgroundThe traditional Chinese medicine Ginseng-Angelica-Shanseng-Pulvis (GASP) has been used to treat stroke for 300 years. This present study investigated if it can induce increases in neurogenesis following cerebral ischemic injury.MethodsRats following middle cerebral artery occlusion were orally treated with high, medium, and low doses of a standardized GASP extract.ResultsAfter 14 days, treatment with GASP improved regional blood flow and infarction volume by magnetic resonance imaging scanning, enhanced Ki67+ expression in the subventricular zone, increased brain-derived neurotrophic factor (BDNF) secretion, Nestin, and bone morphogenetic protein (BMP) 2/4 expressions in the hippocampus in a dose-dependent manner. Interestingly, low-dose treatment with GASP downregulated doublecortin and Notch1 expressions in the hippocampus, as well as upregulated glial fibrillary acidic protein expression in the subgranular zone and hairy and enhancer of split (Hes) 5 expression in the hippocampus, while treatment with middle and high doses of GASP reversed these results. Meanwhile, the consumed time was shortened in the basket test and the adhesive removal test and the spending time on exploring novel objects was prolonged by GASP treatment whose effects were more obvious at day 14 post-ischemia.ConclusionOur study demonstrates that treatment with GASP increases neurogenesis and ameliorates sensorimotor functions and recognition memory. We hypothesize that these effects are thought be mediated by an effect on the BMP2/4 pathway and Notch1/Hes5 signal. Due to its beneficial efficacy, GASP can be recognized as an alternative therapeutic agent for ischemic stroke