2,611 research outputs found

    Two-Stage Acidic-Alkaline Hydrothermal Pretreatment of Lignocellulose for the High Recovery of Cellulose and Hemicellulose Sugars

    Get PDF
    The focus of this work was to develop a combined acid and alkaline hydrothermal pretreatment of lignocellulose that ensures high recovery of both hexose and pentose. Dilute sulfuric acid and lime pretreatments were employed sequentially. Process performance was optimized in terms of catalyst concentration, retention time, and temperature using response surface methodology. Medium operational conditions in the acid stage and harsh conditions in the alkaline stage were desirable with optimal performance at 0.73wt% H2SO4, 150°C, 6.1min in the first stage, and 0.024g lime/g biomass, 202°C, 30min in the second stage. In comparison to single-stage pretreatments with high recovery of either glucose or xylose, two-stage process showed great promises with >80% glucose and >70% xylose recovery. In addition, the method greatly improved ethanol fermentation with yields up to 0.145g/g Miscanthus, due to significantly reduced formation of inhibitory by-products such as weak acids, furans, and phenols. Supplementing biomimetic acids would further increase glucose yield by up to 15% and xylose yield by 25

    Materials and extracellular matrix rigidity highlighted in tissue damages and diseases: Implication for biomaterials design and therapeutic targets

    Get PDF
    Rigidity (or stiffness) of materials and extracellular matrix has proven to be one of the most significant extracellular physicochemical cues that can control diverse cell behaviors, such as contractility, motility, and spreading, and the resultant pathophysiological phenomena. Many 2D materials engineered with tunable rigidity have enabled researchers to elucidate the roles of matrix biophysical cues in diverse cellular events, including migration, lineage specification, and mechanical memory. Moreover, the recent findings accumulated under 3D environments with viscoelastic and remodeling properties pointed to the importance of dynamically changing rigidity in cell fate control, tissue repair, and disease progression. Thus, here we aim to highlight the works related with material/matrix-rigidity-mediated cell and tissue behaviors, with a brief outlook into the studies on the effects of material/matrix rigidity on cell behaviors in 2D systems, further discussion of the events and considerations in tissue-mimicking 3D conditions, and then examination of the in vivo findings that concern material/matrix rigidity. The current discussion will help understand the material/matrix-rigidity-mediated biological phenomena and further leverage the concepts to find therapeutic targets and to design implantable materials for the treatment of damaged and diseased tissues

    Practical Controller Design of Three-Phase Dual Active Bridge Converter for Low Voltage DC Distribution System

    Get PDF
    In a low voltage DC (LVDC) distribution system, isolated bi-directional DC-DC converters are key devices to control power flows. A three-phase dual-active-bridge (3P-DAB) converter is one of the suitable candidates due to inherent soft-switching capability, low conduction loss, and high-power density. However, the 3P-DAB converter requires a well-designed controller due to the influence of the equivalent series resistance (ESR) of an output filter capacitor, degrading the performance of the 3P-DAB converter in terms of high-frequency noise. Unfortunately, there is little research that considers the practical design methodology of the 3P-DAB converter's controller because of its complexity. In this paper, the influence of the ESR on the 3P-DAB converter is presented. Additionally, the generalized average small-signal model (SSM) of the 3P-DAB converter including the ESR of the capacitive output filter is presented. Based on this model, an extended small-signal model and appropriate controller design guide, and performance comparison are presented based on the frequency domain analysis. Finally, experimental results verify the validity of the proposed controller using a 25 kW prototype 3P-DAB converter

    NFATc1 regulates the transcription of DNA damage-induced apoptosis suppressor

    Get PDF
    AbstractDNA damage induced apoptosis suppressor (DDIAS), or human Noxin (hNoxin), is strongly expressed in lung cancers. DDIAS knockdown induced apoptosis in non-small cell lung carcinoma A549 cells in response to DNA damage, indicating DDIAS as a potential therapeutic target in lung cancer. To understand the transcriptional regulation of DDIAS, we determined the transcription start site, promoter region, and transcription factor. We found that DDIAS transcription begins at nucleotide 212 upstream of the DDIAS translation start site. We cloned the DDIAS promoter region and identified NFAT2 as a major transcription factor (Im et al., 2016 [1]). We demonstrated that NFATc1 regulates DDIAS expression in both pancreatic cancer Panc-1 cells and lung cancer cells

    Effect of a multi-layer infection control barrier on the micro-hardness of a composite resin

    Get PDF
    OBJECTIVE: The aim of this study was to evaluate the effect of multiple layers of an infection control barrier on the micro-hardness of a composite resin. MATERIAL AND METHODS: One, two, four, and eight layers of an infection control barrier were used to cover the light guides of a high-power light emitting diode (LeD) light curing unit (LCU) and a low-power halogen LCU. The composite specimens were photopolymerized with the LCUs and the barriers, and the micro-hardness of the upper and lower surfaces was measured (n=10). The hardness ratio was calculated by dividing the bottom surface hardness of the experimental groups by the irradiated surface hardness of the control groups. The data was analyzed by two-way ANOVA and Tukey's HSD test. RESULTS: The micro-hardness of the composite specimens photopolymerized with the LED LCU decreased significantly in the four- and eight-layer groups of the upper surface and in the two-, four-, and eight-layer groups of the lower surface. The hardness ratio of the composite specimens wa

    Physical properties and biological effects of mineral trioxide aggregate mixed with methylcellulose and calcium chloride

    Get PDF
    Objectives: Methylcellulose (MC) is a chemical compound derived from cellulose. MTA mixed with MC reduces setting time and increases plasticity. This study assessed the influence of MC as an anti-washout ingredient and CaCl2 as a setting time accelerator on the physical and biological properties of MTA. Material and Methods: Test materials were divided into 3 groups; Group 1(control): distilled water; Group 2: 1% MC/CaCl2; Group 3: 2% MC/CaCl2. Compressive strength, pH, flowability and cell viability were tested. The gene expression of bone sialoprotein (BSP) was detected by RT-PCR and real­ time PCR. The expression of alkaline phosphatase (ALP) and mineralization behavior were evaluated using an ALP staining and an alizarin red staining. Results: Compressive strength, pH, and cell viability of MTA mixed with MC/CaCl2 were not significantly different compared to the control group. The flowability of MTA with MC/CaCI2 has decreased significantly when compared to the control (

    Clinical outcomes of spontaneous bacterial peritonitis due to extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella species: A retrospective matched case-control study

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Clinical outcomes of spontaneous bacterial peritonitis (SBP) due to extended-spectrum β-lactamase-producing <it>Escherichia coli </it>and <it>Klebsiella </it>species (ESBL-EK) have not been adequately investigated.</p> <p>Methods</p> <p>We conducted a retrospective matched case-control study to evaluate the outcomes of SBP due to ESBL-EK compared with those due to non-ESBL-EK. Cases were defined as patients with liver cirrhosis and SBP due to ESBL-EK isolated from ascites. Control patients with liver cirrhosis and SBP due to non-ESBL-EK were matched in a 3:1 ratio to cases according to the following five variables: age (± 5 years); gender; species of infecting organism; Child-Pugh score (± 2); Acute Physiological and Chronic Health Evaluation II score (± 2). 'Effective initial therapy' was defined as less than 72 hours elapsing between the time of obtaining a sample for culture and the start of treatment with an antimicrobial agent to which the EK was susceptible. Cephalosporin use for ESBL-EK was considered 'ineffective', irrespective of the minimum inhibitory concentration. ESBL production was determined according to the Clinical and Laboratory Standards Institute guidelines on stored isolates.</p> <p>Results</p> <p>Of 1026 episodes of SBP in 958 patients from Jan 2000 through Dec 2006, 368 (35.9%) episodes in 346 patients were caused by SBP due to EK, isolated from ascites. Of these 346 patients, twenty-six (7.5%) patients with SBP due to ESBL-EK were compared with 78 matched controls. Treatment failure, evaluated at 72 hours after initial antimicrobial therapy, was greater among the cases (15/26, 58% <it>vs</it>. 10/78, 13%, <it>P </it>= .006); 30-day mortality rate was also higher than in the controls (12/26, 46% <it>vs</it>. 11/78, 15%, <it>P </it>= .001). When the case were classified according to the effectiveness of the initial therapy, 'ineffective initial therapy' was associated with higher 30-day mortality rate (11/18, 61% <it>vs</it>. 1/8, 13%, <it>P </it>= .036).</p> <p>Conclusion</p> <p>SBP due to ESBL-EK had poorer outcomes than SBP due to non-ESBL-EK. Ineffective initial therapy seems to be responsible for the higher rate of treatment failure and mortality in SBP due to ESBL-EK.</p

    Causes and effects of 2008 financial crisis

    Get PDF
    Beginning in the mid 2007’s the US financial market started to slide into the “worst financial crisis since the Great Depression of the early 1930’s” (Thakor, 2015: p.156). The domino effect of several events and occasions were leading first to a countrywide recession in the USA then later spreading globally. In the following this term paper will deal with the main causes and effects of 2008 financial crisis. Unlike other topics in literature there is no consensus about the question of guilt in this sense. Among economists there are different approaches to explain the main causes of the financial crisis
    corecore