Comparative Performance of Zymomonas mobilis and Saccharomyces cerevisiae in Alcoholic Fermentation of Saccharified Wheat Starch B in a Continuous Dynamic Immobilized Biocatalyst Bioreactor

Glucose derived from an industrial, enzymatically saccharified wheat starch fraction (B starch) was investigated for ethanol production using free and immobilized cells of Saccharomyces cerevisiae and Zymomonas mobilis. Batch cultures of these organisms could successfully ferment this substrate within 24 h giving 7% ethanol by volume and over 96% sugar conversion. Fermentation with S cerevisiae and Z. mobilis immobilized on rotating fiber discs in a continuous dynamic biocatalyst bioreactor (CDIBB) resulted in very rapid and efficient fermentation and concurrent high ethanol productivity. Z. mobilis loaded at 30g/I cell density (based on bioreactor volume, 31) fermented saccharified wheat starch B slurry at 15% solids and having 128g/I glucose, in 0.9 h with 92% sugar utilization; and volumetric productivity based on liquid hold up was 65.5 g/I-h, being threefold higher than that obtained with immobilized yeast cells. Z. mobilis appears to be the preferred organism for the rapid fermentation of glucose rich solutions in the CDIBB. Advantages and the possible application of this bioreactor system to alcoholic fermentation of industrial derived substrates associated with high suspended solids are discussed. Die aus einer industriellen, enzymatisch verzuckerten Weizen-B-Stärke gewonnene Glucose wurde unter Verwendung von freien und immobilisierten Zellen von Saccharomyces cerevisiae und Zymomonas mobilis hinsichtlich der Ethanolgewinnung untersucht. Chargenweise Kulturen dieser Organismen vergoren dieses Substrat erfolgreich 24h; sie ergaben 7 Vol.% Ethanol bei 96% iger Zuckerumwandlung. Die Vergärung mit auf rotierenden Faserplatten immobilisierten S. cerevisiae und Z. mobilis in einem kontinuierlichen, dynamischen Biokatalysator-Bioreaktor (CDIBB) führte zu sehr schneller und wirksamer Gärung und vergleichbar hoher Ethanolproduktivität. Mit einer Zelldichte von 30g/1 (bez. auf das Bioreaktorvolumen, 31) gepackte Z. mobilis vergor eine Weizen-B-Stärkesuspension mit 15% Feststoff und 128g Glucose/1 in 0,9h bei 92% Zuckerverwertung. Die Volumenproduktivität, bezogen auf die Flüssigkeitsrückhaltung, betrug 65,5 g/1-h und war damit dreimal so hoch wie bei immobilisierten Hefezellen. Z. mobilis dürfte der bevorzugte Organismus für die rasche Vergärung von glucosereichen Lösungen im CDIBB sein. Die Vorteile und die mögliche Anwendung dieses Bioreaktorsystems für die alkoholische Vergärung von industriellen Substraten in Verbindung mit hoch suspendierten Feststoffen werden diskutiert.     

Extracellular Vesicles Secreted by Corneal Myofibroblasts Promote Corneal Epithelial Cell Migration

Corneal epithelial wound healing is a multifaceted process that encompasses cell proliferation, migration, and communication from the corneal stroma. Upon corneal injury, bidirectional crosstalk between the epithelium and stroma via extracellular vesicles (EVs) has been reported. However, the mechanisms by which the EVs from human corneal keratocytes (HCKs), fibroblasts (HCFs), and/or myofibroblasts (HCMs) exert their effects on the corneal epithelium remain unclear. In this study, HCK-, HCF-, and HCM-EVs were isolated and characterized, and human corneal epithelial (HCE) cell migration was assessed in a scratch assay following PKH26-labeled HCK-, HCF-, or HCM-EV treatment. HCE cells proliferative and apoptotic activity following EV treatment was assessed. HCF-/HCM-EVs were enriched for CD63, CD81, ITGAV, and THBS1 compared to HCK-EV. All EVs were negative for GM130 and showed minimal differences in biophysical properties. At the proteomic level, we showed HCM-EV with a log >two-fold change in CXCL6, CXCL12, MMP1, and MMP2 expression compared to HCK-/HCF-EVs; these proteins are associated with cellular movement pathways. Upon HCM-EV treatment, HCE cell migration, velocity, and proliferation were significantly increased compared to HCK-/HCF-EVs. This study concludes that the HCM-EV protein cargo influences HCE cell migration and proliferation, and understanding these elements may provide a novel therapeutic avenue for corneal wound healing.     

Solubilization of Aromatic Hydrocarbons in Ethylene Oxide-Propylene Oxide Triblock Micelles: Location of Solubilizate and its Effect on Micelle Size from 2D NMR and Scattering Techniques

The solubilization of benzene and toluene in micellar solutions and the effects on the micellization and micelle size of ethylene oxide-propylene oxide triblock copolymers were investigated by dynamic light scattering (DLS), small angle neutron scattering (SANS), and 2D NMR spectroscopy. The copolymeric surfactants have the same size as the middle hydrophobic polypropylene oxide block (Mol. Wt. 3250) and varying polyethylene oxide end blocks (30, 40 and 50%). The solubilization and the properties of the micelles in the presence of the solubilizates were investigated; the results reveal that the more hydrophobic copolymer showed better solubilization. The cloud points of the copolymers decreased in the presence of oils; the depression in the cloud point is due to the formation of an electron donor–acceptor complex. DLS shows that the effect of benzene is dominated at high oil concentration. SANS data show that the micelles remain spherical in shape and that the micellar core size does not change with higher benzene concentration; observed changes in the low scattering vector region could be because of some small amount of benzene clusters formed at higher benzene concentration. Finally, the locus of solubilization of the oils in the copolymer micelles was determined via 2D NMR experiments. In all cases, significant nuclear Overhauser effect spectroscopy (NOESY) cross peaks were observed that appeared to correlate well with the expected loci of these solubilizates in micelles. Hence, the noninvasive NOESY technique provides important information on the location of the aromatic solubilizates in these copolymer micelles that depends on the structure of the oils.     

A comprehensive study on face recognition: methods and challenges

ABSTRACT

Face Recognition is the process of identifying and verifying the faces. Face recognition has vast importance in the field of Security, Healthcare, Banking, Criminal Identification, Payment, and Advertising. In this paper, we have reviewed various techniques and challenges for the face recognition. Illumination, pose variation, facial expressions, occlusions, aging, etc. are the key challenges to the success of face recognition. Pre-processing, Face Detection, Feature Extraction, Optimal Feature Selection, and Classification are primary steps in any face recognition system. This paper provides a detailed review of each. Feature extraction techniques can be classified as appearance-based methods or geometry-based methods, such method may be local or global. Feature extraction is the most crucial stage for the success of the face recognition system. However, deep learning methods have freed the user from handcrafting the features. In this article, we have surveyed state-of-the-art methods of last few decades and the comparative study of various feature extraction methods is provided. Article also describes the current challenges in the area.     

Performance validation tests on 80 K bubble type of shields for SST-1

The 80 K thermal shields of Steady State Superconducting Tokamak (SST-1) minimize the steady state heat loads on the superconducting magnet system at 4.5 K from ambient. Uniform temperature, vacuum and cryo compatibility is desired for the 80 K shields. In order to meet these requirements, the bubble/embossed type of design concept is adopted. This design ensures lower pressure drop and better temperature uniformity within ±5 K. Special attention has been given for preventing direct radiation on the magnet system. As part of performance validation tests, a group of 80 K thermal shields have undergone rigorous testing protocols and procedures. The temperature distribution, helium leak tightness and insulation resistance tests have been carried out for SST-1 thermal shields before final assembly of the machine. The test design, procedures and results of the 80 K thermal shields will be discussed in this paper.     

Mechanisms for ganciclovir resistance in gastrointestinal tumor cells transduced with a retroviral vector containing the herpes simplex virus thymidine kinase gene

Transfer of the herpes simplex thymidine kinase (HSV-TK) gene into tumor cells confers sensitivity to the cells to the viral drug ganciclovir (GCV). Although the efficacy of the HSV-TK/GCV approach is well studied, the mechanisms for the resistance of HSV-TK-transduced tumor cells to GCV are poorly understood. Here, we examined the mechanisms for GCV resistance in HSV-TK-transduced gastrointestinal (GI) cell lines. Our results show that GCV sensitivities vary in vitro and in vivo among the different HSV-TK-transduced GI tumor cell lines. GCV-resistant colonies were isolated from several different HSV-TK-transduced GI tumor cell lines after 14 days of GCV treatment. Characterization of GCV-resistant colonies demonstrated that the HSV-TK gene was either partially or completely deleted from the resistant HSV-TK-transduced cells. In the HT-29 RM and MIAPACA-2 RM cells, a 220-bp deletion of the gene was found, whereas in the HT-29 R1-R5-resistant cells, the whole TK gene was found to be absent. Immunocytochemical studies using a polyclonal antibody to the TK protein demonstrated that the HSV-TK protein was absent in the GCV-resistant, HSV-TK-transduced cells. Transfection of the resistant cells with an adenoviral vector containing a HSV-TK gene restored sensitivity to GCV. The presence of GCV-resistant cells was only demonstrable in GI tumor cell lines that also demonstrated a poor bystander effect. Our results suggest that GCV resistance found in tumor cells transduced with a retroviral HSV-TK gene is due to the lack of a functional TK protein in the tumor cells rather than any intrinsic resistance of the cells to GCV. In tumor cells with a good bystander effect, the small percentage of TK-transduced cells that do not express the TK protein are probably killed by the bystander effect because GCV-resistant tumor cells were not found in these cell lines. GCV-resistant tumor cells were found only in tumor cell lines with a poor bystander effect, by which, presumably, the transduced tumor cells lacking a functional TK gene were not killed by the bystander killing effect.     

Prevalence of minor psychiatric disorders in an adult African rural community in South Africa

BACKGROUND: This paper reports on a two-stage community-based epidemiological study of selected minor psychiatric disorders conducted on an adult African population in South Africa. METHODS: Using a modified random cluster sampling method, 354 adults were identified as the first-stage sample, with the SRQ-20 being used as a first-stage screen. Clinical interviews based on DSM-IV checklists for generalized anxiety disorder, major depression and dysthymia were administered as the second-stage criterion to 81 subjects from the sample. RESULTS: The weighted prevalence for generalised anxiety and depressive disorders was 23.9% (95% CI 15.1%-32.7%), comprising: generalized anxiety 3.7%, major depression 4.8%, dysthymia 7.3%, and major depression and dysthymia 8.2%. Statistically significant associations were found between caseness and age, marital status, employment, income and educational level. CONCLUSIONS: The results are discussed in relation to comparative local and international data as well as in the context of the current restructuring of the mental-health care system in South Africa from tertiary curative care to integrated primary mental-health care.     

Improved Approximations for Tour and Tree Covers

A tree (tour) cover of an edge-weighted graph is a set of edges which forms a tree (closed walk) and covers every other edge in the graph. Arkin et al. give approximation algorithms with ratios 3.55 (tree cover) and 5.5 (tour cover). We present algorithms with a worst-case ratio of 3 for both problems.     

Ca2+-dependent capacitance increases in rat basophilic leukemia cells following activation of store-operated Ca2+ entry and dialysis with high-Ca2+-containing intracellular solution

Ca2+-dependent vesicular fusion was studied in single whole-cell patch-clamped rat basophilic leukemia (RBL) cells using the capacitance technique. Dialysis of the cells with 10 microM free Ca2+ and 300 microM guanosine 5'-O-(3-thiotriphosphate) (GTP[gamma-S]) resulted in prominent capacitance increases. However, dialysis with either Ca2+ (225 nM to 10 microM) or GTP[gamma-S] alone failed to induce a capacitance change. Under conditions of weak Ca2+ buffering (0.1 mM EGTA), activation of Ca2+-release-activated Ca2+ (CRAC) channels by dialysis with inositol 1,4,5-trisphosphate (InsP3) failed to induce a capacitance increase even in the presence of GTP[gamma-S]. However, when Ca2+ATPases were inhibited by thapsigargin, InsP3 and GTP[gamma-S] led to a pronounced elevation in membrane capacitance. This increase was dependent on a rise in intracellular Ca2+ because it was abolished when cells were dialysed with a high level of EGTA (10 mM) in the recording pipette. The increase was also dependent on Ca2+ influx because it was effectively suppressed when external Ca2+ was removed. Our results demonstrate that ICRAC represents an important source of Ca2+ for triggering a secretory response.     

Relationships between thyroid hormone and antidepressant responses to total sleep deprivation in mood disorder patients

BACKGROUND: Acute transient antidepressant effects of sleep deprivation are consistently observed in 50% of depressed patients, but the mechanisms of these, at times, dramatic improvements in mood have not been adequately elucidated. Some, but not all, studies suggest a relationship to increased thyroid-stimulating hormone (TSH) secretion. METHODS: TSH and other thyroid indices were measured at 8:00 AM after a baseline night's sleep and at 8:00 AM following a night of total sleep deprivation (S.D.) in 34 medication-free, affective disorder patients assessed with Hamilton, Beck, and Bunney-Hamburg depression ratings as well as two hourly self-ratings on a visual analog scale. RESULTS: Compared with baseline, S.D. induced highly significant increases in TSH, levothyroxine, free levothyroxine, and triiodothyronine. The 12 S.D. responders tended to have greater TSH increases than the 15 nonresponders (p < .10). The change in Beck depression ratings significantly correlated with the change in TSH (r = -.40, p = .0496, n = 24). CONCLUSIONS: These data are consistent with several other reports of a significant relationship between degree of antidepressant response to S.D. and increases in TSH measured at 8:00 AM near their usual nadir. Acute removal of the sleep-related break on the hypothalamic-pituitary-thyroid axis remains a promising candidate for the mechanism of sleep deprivation-induced improvement in mood in depressed patients.