192 research outputs found
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Mechanism of Exact Transition between Cationic and Anionic Redox Activities in Cathode Material Li2FeSiO4.
The discovery of anion redox activity is promising for boosting the capacity of lithium ion battery (LIB) cathodes. However, fundamental understanding of the mechanisms that trigger the anionic redox is still lacking. Here, using hybrid density functional study combined with experimental soft X-ray absorption spectroscopy (sXAS) measurements, we unambiguously proved that Li(2- x)FeSiO4 performs sequent cationic and anionic redox activity through delithiation. Specifically, Fe2+ is oxidized to Fe3+ during the first Li ion extraction per formula unit (f.u.), while the second Li ion extraction triggered the oxygen redox exclusively. Cationic and anionic redox result in electron and hole polaron states, respectively, explaining the poor conductivity of Li(2- x)FeSiO4 noted by previous experiments. In contrast, other cathode materials in this family exhibit diversity of the redox process. Li2MnSiO4 shows double cationic redox (Mn2+-Mn4+) during the whole delithiation, while Li2CoSiO4 shows simultaneous cationic and anionic redox. The present finding not only provides new insights into the oxygen redox activity in polyanionic compounds for rechargeable batteries but also sheds light on the future design of high-capacity rechargeable batteries
Enhancing the Performance of Practical Profiling Side-Channel Attacks Using Conditional Generative Adversarial Networks
Recently, many profiling side-channel attacks based on Machine Learning and
Deep Learning have been proposed. Most of them focus on reducing the number of
traces required for successful attacks by optimizing the modeling algorithms.
In previous work, relatively sufficient traces need to be used for training a
model. However, in the practical profiling phase, it is difficult or impossible
to collect sufficient traces due to the constraint of various resources. In
this case, the performance of profiling attacks is inefficient even if proper
modeling algorithms are used. In this paper, the main problem we consider is
how to conduct more efficient profiling attacks when sufficient profiling
traces cannot be obtained. To deal with this problem, we first introduce the
Conditional Generative Adversarial Network (CGAN) in the context of
side-channel attacks. We show that CGAN can generate new traces to enlarge the
size of the profiling set, which improves the performance of profiling attacks.
For both unprotected and protected cryptographic algorithms, we find that CGAN
can effectively learn the leakage of traces collected in their implementations.
We also apply it to different modeling algorithms. In our experiments, the
model constructed with the augmented profiling set can reduce the required
attack traces by more than half, which means the generated traces can provide
useful information as the real traces
Leczenie oksytocyną zapobiega stłuszczeniu szpiku kostnego obserwowanemu u królików z cukrzycą wywołaną alloksanem — badanie przy użyciu protonowej spektroskopii rezonansu magnetycznego
Introduction: Oxytocin might be used therapeutically as an ally to rescue osteopathy resulting from diabetes. However, the in vivo effects of oxytocin on marrow adipogenesis in diabetes remain unknown. In this longitudinal study, we aimed to investigate the protective effects of oxytocin on diabetes-induced marrow adiposity in rabbits using proton MR spectroscopy.
Material and methods: Forty-five female New Zealand rabbits were randomly divided into controls, diabetes, and diabetes treated with oxytocin (ip, 0.78 mg/kg) for six months. Marrow fat fraction (FF) was determined by proton MR spectroscopy at baseline, and at three and six months. Bone mineral density was measured by dual-energy X-ray absorptiometry. Serum biomarkers, glycolipid metabolism, and histological analysis of marrow adipocytes were determined.
Results: Oxytocin treatment had positive metabolic effects in diabetic rabbits, which was based on the changes in glucose metabolism, insulin sensitivity, and lipid profiles. The diabetic rabbits demonstrated dramatic marrow adiposity in a time-dependent manner; at three and six months the FF percentage changes from baseline were 10.1% and 25.8%, respectively (all P < 0.001). Moreover, oxytocin treatment significantly reversed FF values and quantitative parameters of marrow adipocyte in diabetic rabbits to levels of naive control rabbits. Oxytocin improved bone formation marker in diabetic rabbits compared to the saline group. Also, treatment of diabetic rabbits with oxytocin significantly mitigated bone deterioration when compared with the saline-treated diabetic group (all P < 0.05).
Conclusions: Oxytocin appears to alleviate harmful effects of hyperglycaemia on marrow adiposity. Proton MR spectroscopy may be a valuable tool, providing complementary information on efficacy assessments.Wstęp: Oksytocyna może być stosowana terapeutycznie w osteopatii wynikającej z cukrzycy, jednakże jej wpływ in vivo na stłuszczenie szpiku kostnego w przebiegu cukrzycy pozostaje niezbadany. Niniejsze badanie przekrojowe ma na celu zbadać ochronne działanie oksytocyny na wywołane cukrzycą stłuszczenie szpiku kostnego u królików przy użyciu protonowej spektroskopii rezonansu magnetycznego.
Materiał i metody: Czterdzieści pięć samic królików nowozelandzkich podzielono losowo na grupę kontrolną, grupę z cukrzycą oraz grupę z cukrzycą leczoną oksytocyną (0.78 mg/kg, i.p.) przez sześć miesięcy. Frakcja tłuszczu (ang. fat fraction; FF) szpiku kostnego została określona za pomocą protonowej spektroskopii rezonansu magnetycznego na początku badania oraz po trzech i sześciu miesiącach. Gęstość mineralną kości zmierzono za pomocą absorpcjometrii promieniowania rentgenowskiego o podwójnej energii. Określono również biomarkery surowicy krwi, metabolizm glikolipidów oraz sporządzono analizę histologiczną adipocytów szpiku kostnego.
Wyniki: Leczenie oksytocyną przyniosło pozytywne efekty metaboliczne u królików z cukrzycą, co stwierdzono na podstawie zmian w metabolizmie glukozy, wrażliwości na insulinę oraz profili lipidowych. Zauważono drastyczny wzrost stłuszczenia szpiku kostnego u królików z cukrzycą w sposób zależny od czasu; po trzech i sześciu miesiącach, procentowe zmiany frakcji tłuszczu w stosunku do wartości wyjściowej wynosiły odpowiednio 10,1% i 25,8% (wszystkie P < 0.001). Co więcej, leczenie oksytocyną znacząco odwracało wartości frakcji tłuszczu oraz ilościowe parametry adipocytów szpiku kostnego u królików z cukrzycą do poziomu królików z grupy kontrolnej. Oksytocyna poprawiała marker tworzenia kości u królików z cukrzycą w porównaniu do grupy, której podawano sól fizjologiczną. Ponadto, leczenie oksytocyną królików z cukrzycą znacząco łagodziło niszczenie kości w porównaniu do grupy z cukrzycą, której podawano sól fizjologiczną (wszystkie P < 0.05).
Wnioski: Oksytocyna wydaje się zmniejszać szkodliwy wpływ hiperglikemii na stłuszczenie szpiku kostnego. Protonowa spektroskopia rezonansu magnetycznego może być cennym narzędziem, dostarczającym uzupełniających informacji na temat oceny skuteczności leczenia
Electrospun Nanofibrous Membrane for Air Filtration
Nanofibers have a large potential in air filtration applications, so this paper explores the performance of electrospun nanofiber membrane compared to traditional filtration fabrics. Poly (ethylene oxide) (PEO) and Polyvinyl Alcohol (PVA) were electrospun into nanofibrous membranes and analyzed their filtration attributes. Experimentation revealed that nanofibrous membranes have higher filtration efficiency than traditional filtration fabrics, such as meltblown and needle filtration material. In addition, Nanofibrous membranes under the same electrospinning process but with different materials had similar high filtration efficiency, while their permeability had obvious difference. We suggest that different structure in the nanofiber membrane should cause this difference. Our work proves that there is a large potential for nanofiber membranes to utilize in air filtration area
Fabrication of micro/nanometer-channel by Near-Field ElectroSpinning
Direct-written polymer micro/nanofiber from Near- Field ElectroSpinning (NFES) was utilized as shadow-mask to fabricate uniform micro/nanometer-channel. Both Single straight microfiber (line-width 2~10?? m) and nanofiber (diameter 200~800nm) were direct-written on the substrate with the NFES setup, and then 2-nm-thick titanium adhesive layer and 10-nm- thick gold layer were sputtered on the substrate successively. By the ultrasonication process in acetone and de-ionized water, the polymer fiber was removed and micro/nanometer-channel with gap width ranging from 7?? m to 700nm was formed. The fabrication process and related technical issues were also outlined in this work. The experimental results revealed that the micro/nanometer channel had a good uniformity, above 90% of the gap length value lied within the deviation range of ±3%. This simple and facile method can be used to define the uniform micro/nano channel for organic thin film transistors. submicron-gap electrode by using an electrospun single fiber as shadow-mask. This is a simple and cost-effective method, yet the nanofiber used as shadow-mask was obtained through the post-stretching process, which increased the complexity and uncertainty of fabrication process. In this paper, Direct-write (DW) technology (9) based on Near-Field ElectroSpinning (NFES) (10) was utilized to obtain single straight micro/nanofiber directly, and used as shadow- mask to fabricate micro/nanometer-channel. The gap length of micro/nanometer-channel was in the range of 700nm to 7?? m. The fabrication process and related technical issues were described, and then the uniformity of micro/nanometer-channel was also evaluated and discussed
Direct-Write Micro/Nano-Structure For Flexible Electronic Manufacturing
This article focuses on optimizing the electrospinning parameters, and developing a new method of Direct-Write (DW) micro/nano-structure based on Near-Field Electrospinning (NFES) for flexible electronic manufacturing. NFES is a new way to realize controllable electrospinning and precision-positioning of nanofiber, by which nano-structure with diameter from 50nm to 500nm can be fabricated orderly and accurately. A tungsten electrode with tip diameter of 25 mu m is used to DW nano-structure, with the minimum bias voltage 600V, minimum electrode to collector distance 500 mu m. A microstructure DW system is designed, by which micro-structure with diameter of several micrometers can be drawn. In this work a needle tube of 232 mu m inside diameter is used as spinneret, electrode to collector distance is various from 2mm to 10mm, and the collector moving speed ranges from 0.07m/s to 7m/s. The DW process and character of micro-structure such as line width, smoothness and thickness can be controlled by optimizing the electrospinng parameters. The DW micro/nano-structure is continuous and smooth, which can be drawn on expected site and in expected direction with accurate dimension. The new method based on NEFS with the advantage of narrower line width and smoother structure than traditional flexible electronic manufacturing technologies, which is more suitable for the development of flexible electronic manufacturing
Large-scale patterned nanofibers via tip-less electrospinning
Tip-less Electrospinning (TLES) process has been developed to produce polymer nanofibers with high throughput. And the ameliorated collector with parallel top-down configurations of two different materials in conventional electrospinning, such as polyethylene terephthalate (PET)-glass, copper-glass and PET-silicon etc, can achieve patterned nanofibers to expand its future applications. In this paper such patterned collectors array with changed electric field around, are introduced to TLES to deposit large-scale patterned nanofibers. The experiment results show that patterned nanofibers can be collected along the gap between plastic plates in both plastic-glass and plastic-silicon configuration. To the copper-glass collector, nanofibers bridge over the gap and the nanofiber quantity density on the gap is much less than that on the copper. But the patterned effects in all configurations are relatively weaker than that from foremetioned spinning due to their much higher speed, more serious bending instability and repulsive interactions between as-spun nanofibers
Bead-on-string structure formed by electrohydrodynamic printing
A Bead-on-String (B-S) structure which consists of droplet and filament is generated based on electrohydrodynamic printing system. The formation process of the B-S structure is demonstrated and discussed. Subsequently, the influence of the substrate moving speed on the B-S structure is investigated. The size of the droplet in the B-S structure decreases with the substrate moving speed. When the substrate moving speed is higher than the jetting speed, satellite droplet will appear and its number increases with the substrate moving speed. The effect of the solution concentration on the deposited patterns is also studied. A continuous line is printed with 3 wt% PEO solution. The B-S structure is generated when the concentration of the PEO solution is within 5-15 wt%. Moreover, the size of the droplet decreases with the increasing of the solution concentration. At the concentration of 18 wt%, nanofiber is produced and a pattern similar to the B-S structure is deposited on the substrate
Calycosin attenuates dextran sulfate sodium (DSS)-induced experimental colitis
Objective(s):Inflammatory bowel disease (IBD) results from dysregulation of intestinal mucosal immunity. It is an incurable disease that affects millions of people worldwide. Developing new strategies for the treatment of colitis has been a major challenge. Here, we report the effect of calycosin, a plant-derived flavonoid, in successfully managing colitis in murine model. Material and Methods:In vivo model of colitis was induced using 2.5% (w/v) dextran sodium sulfate (DSS, 36,000 to 50,000 Mw). Body weight and disease activity index (DAI) were evaluated every day. Hematoxylin-Eosin (H&E) staining was used to estimate the effect of calycosin on DSS-induced colon damage. The levels of proinflammatory genes and mRNA expression were determined using real-time PCR, whereas the proinflammatory cytokines were assessed with ELISA. The content of other parameters including myeloperoxidase (MPO), glutathione (GSH), superoxide dismutase (SOD) and malondialdehyde (MDA) were also evaluated. Western blot assay was further used to determine the effect of calycosin on both NF-κB and mitogen activated protein kinases (MAPK) pathways. Results: The results showed that calycosin prevented weight loss and shortening of the colon length, maintained an intact mucosa, increased GSH and SOD activities, and decreased MDA levels. The drug also significantly inhibited proinflammatory cytokine mRNA expression and decreased MPO activity. Additionally, it remarkably inhibited NF-κB pathway and c-Jun N-terminal kinase (JNK) phosphorylation with no effect on p38 and extracellular signal-regulated kinase (ERK1/2) phosphorylation levels in colon tissue. Conclusion: These findings revealed that calycosin successfully ameliorated the effect of DSS-induced colitis in mice, which could be associated with NF-κB and JNK pathway modulations
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