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Essential oil of Piper betle leaves in Quang Nam-Da Nang do obtain via the steam distillation method with oil collection efficiency reaching 0.83%. The chemical composition of the essential oil from Piper betle leaves in Quang Nam-Da Nang is determined via the GC-MS method that includes 21 components (99.68%), among which the main components are eugenol acetate (32.33%), eugenol (24.56%), 4-allyl-1,2-diacetoxybenzene (19.8%), germacrene D (5.98%), caryophyllene (3.32%), and γ-muurolene (2.45%). The essential oil of Piper betle leaves in Quang Nam-Da Nang also showed moderate anti-acetylcholinesterase activity with IC50 (µg/mL) = 65.94±5.96 and moderate nitric oxide suppressing activity with IC50 (µg/mL) = 46.69±3.57.

The growth and progression of cancers are crucially regulated by the tumor microenvironment where tumor cells and stromal cells are mutually associated. In this study, we found that stomatin expression was markedly upregulated by the interaction between prostate cancer cells and stromal cells. Stomatin suppressed cancer cell proliferation and enhanced apoptosis in vitro and inhibited xenograft tumor growth in vivo. Stomatin inhibited Akt activation, which is mediated by phosphoinositide-dependent protein kinase 1 (PDPK1). PDPK1 protein stability was maintained by its binding to HSP90. Stomatin interacted with PDPK1 and interfered with the PDPK1–HSP90 complex formation, resulting in decreased PDPK1 expression. Knockdown of stomatin in cancer cells elevated Akt activation and promoted cell increase by promoting the interaction between PDPK1 and HSP90. Clinically, stomatin expression levels were significantly decreased in human prostate cancer samples with high Gleason scores, and lower expression of stomatin was associated with higher recurrence of prostate cancer after the operation. Collectively, these findings demonstrate the tumor-suppressive effect of stromal-induced stomatin on cancer cells.Significance:These findings reveal that interactions with stromal cells induce expression of stomatin in prostate cancer cells, which suppresses tumor growth via attenuation of the Akt signaling axis.

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Supplementary Materials & Methods and Figures

A series of Mn4+-activated CaAl2O4 (CAO) compounds were synthesized by co-precipitation to seek a candidate for a red-emitting phosphor to be employed in a white LED. The crystal structure, morphology, and fluorescence properties of the as-obtained phosphors were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence (PL). The deep red luminescence of Mn4+ in CaAl2O4 is reported and discussed. The excitation spectrum exhibited broadband emission between 260 and 550 nm with three peaks dominating at 320 nm due to the transition of 4A24T1. Theemission spectra between 600 to 720 nm displays an overwhelming emission peak at 654 nm owing to the 2E4A2 transition of Mn4+ ion.This research demonstrates the great promise of CaAl2O4:Mn4+ as a commercial red phosphor in warm white LEDs and opens up new avenues for the exploration of novel non-rare-earth red-emitting phosphors.

Whether a small GTPase RhoA plays a role in the pathology of abdominal aortic aneurysm (AAA) has not been determined. We show here that RhoA expression is reduced in human AAA lesions, compared with normal areas. Furthermore, incidence of AAA formation is increased in vascular smooth muscle cell (VSMC)-specific RhoA conditional knockout (cKO) mice. The contractility of the aortic rings and VSMCs from RhoA cKO mice is reduced, and expression of genes related to the VSMC contractility is attenuated by loss of RhoA. RhoA depletion activates the mitogen-activated protein (MAP) kinase signaling, including MAP4K4, in the aorta and VSMCs. Inhibition of MAP4K4 activity by DMX-5804 decreases AAA formation. Set, a binding protein to active RhoA, functions as an activator of MAP4K4 by sequestering PP2A, an inhibitor of MAP4K4, in the absence of RhoA. In conclusion, RhoA counteracts AAA formation through inhibition of MAP4K4 in cooperation with Set.

Transmembrane protein 168 (TMEM168) was found to be localized on the nuclear membrane. A heterozygous mutation (c.1616G>A, p. R539Q) in TMEM168 was identified in patients with Brugada syndrome. This mutation reduced expression of cardiomyocyte sodium channel Nav1.5 via Nedd4-2 E3 ubiquitin ligase-induced ubiquitination and degradation. However, the detailed molecular mechanism provoked by the TMEM168 mutant remains unclear. Here, we demonstrated that small heat shock protein αB-crystallin, which can bind to Nav1.5 and Nedd4-2 and interfere with the association of both proteins, was strongly recruited from the cell surface to the perinuclear region because of the much higher affinity of αB-crystallin with the TMEM168 mutant than with wild-type TMEM168. Following knockdown of αB-crystallin in HL-1 cardiomyocytes, the interaction of Nav1.5 with Nedd4-2 was increased, despite the reduced expression of Nav1.5. Moreover, reduction of Nav1.5 expression by αB-crystallin knockdown was rescued in the presence of a proteasome inhibitor MG-132, suggesting the importance of the αB-crystallin-modulated ubiquitin–proteasome system for the stability of Nav1.5 expression. Collectively, the balance of molecular interactions among Nav1.5, Nedd4-2 and αB-crystallin plays a role in the regulation of cardiomyocyte cell surface expression of Nav1.5, and the TMEM168 mutant disturbs this balance, resulting in a decrease in Nav1.5 expression.

The growth and progression of cancers are crucially regulated by the tumor microenvironment where tumor cells and stromal cells are mutually associated. In this study, we found that stomatin expression was markedly upregulated by the interaction between prostate cancer cells and stromal cells. Stomatin suppressed cancer cell proliferation and enhanced apoptosis in vitro and inhibited xenograft tumor growth in vivo. Stomatin inhibited Akt activation, which is mediated by phosphoinositide-dependent protein kinase 1 (PDPK1). PDPK1 protein stability was maintained by its binding to HSP90. Stomatin interacted with PDPK1 and interfered with the PDPK1–HSP90 complex formation, resulting in decreased PDPK1 expression. Knockdown of stomatin in cancer cells elevated Akt activation and promoted cell increase by promoting the interaction between PDPK1 and HSP90. Clinically, stomatin expression levels were significantly decreased in human prostate cancer samples with high Gleason scores, and lower expression of stomatin was associated with higher recurrence of prostate cancer after the operation. Collectively, these findings demonstrate the tumor-suppressive effect of stromal-induced stomatin on cancer cells. Significance: These findings reveal that interactions with stromal cells induce expression of stomatin in prostate cancer cells, which suppresses tumor growth via attenuation of the Akt signaling axis.

Subject. Currently, the relationship of innovation and economic sustainability has become an important aspect to consider. Analyzing the importance of encouraging the innovation for the economic growth of the Social Republic of Vietnam, we can determine the future of the economic development in many developing countries. Objectives. We substantiate the relationship of innovation and economic sustainability and outline our recommendations for encouraging the innovation and improving the innovative system of Vietnam. Methods. As part of the study, we mainly analyze proceedings on the role of innovation in the economic sustainability, materials of international organizations, and official papers of the Vietnamese government. Results. Having analyzed Global Innovation Index reports from 2013 through 2020, we found achievements and weaknesses of innovations in Vietnam. We determined the main challenges of Vietnam’s innovation system through the comparative analysis of the innovation indices of Vietnam, Singapore, Malaysia and Thailand. The article substantiates priorities for improving the national innovation system of Vietnam, and raising the importance of innovation for the economic sustainability. Conclusions and Relevance. We suggest what should be done to improve innovation in Vietnam. The findings can be used to set up a mechanism for encouraging innovation, which should become the principal driver of the sustainable economic development in Vietnam and other emerging economies.

CONTEXT: On October 6, 2014, the United States Drug Enforcement Administration (DEA) implemented a regulatory change for hydrocodone combination products (HCPs), moving them from Schedule III to II, in an effort to decrease drug overdoses. Existing research suggests this regulatory action reduced HCP prescribing and dispensing; however, there is limited research assessing its possible effects on overdoses and accidental exposures. OBJECTIVE: To analyze the changes in opioid exposures reported to the California Poison Control System (CPCS) before and after DEA rescheduling of HCPs. METHODS: We collected monthly exposure data reported to CPCS from 2012–2019 and conducted interrupted time series analyses to assess changes in exposures after rescheduling for HCPs, tramadol, oxycodone, morphine, codeine, fentanyl, and heroin. Additional analyses were done to assess any changes in exposures resulting in severe outcomes (moderate or major health effects). For HCPs, we also conducted logistic regressions to identify characteristics of exposures resulting in severe outcomes before and after rescheduling. RESULTS: Overall monthly opioid exposures reported to CPCS decreased after DEA rescheduling of HCPs. These decreases were significant for HCP, tramadol, and morphine (p

Heart failure is one of the leading causes of death worldwide. RhoA, a small GTPase, governs actin dynamics in various tissue and cell types, including cardiomyocytes; however, its involvement in cardiac function has not been fully elucidated. Here, we generated cardiomyocyte-specific RhoA conditional knockout (cKO) mice, which demonstrated a significantly shorter lifespan with left ventricular dilation and severely impaired ejection fraction. We found that the cardiac tissues of the cKO mice exhibited structural disorganization with fibrosis and also exhibited enhanced senescence compared with control mice. In addition, we show that cardiomyocyte mitochondria were structurally abnormal in the aged cKO hearts. Clearance of damaged mitochondria by mitophagy was remarkably inhibited in both cKO cardiomyocytes and RhoA-knockdown HL-1 cultured cardiomyocytes. In RhoA-depleted cardiomyocytes, we reveal that the expression of Parkin, an E3 ubiquitin ligase that plays a crucial role in mitophagy, was reduced, and expression of N-Myc, a negative regulator of Parkin, was increased. We further reveal that the RhoA-Rho kinase axis induced N-Myc phosphorylation, which led to N-Myc degradation and Parkin upregulation. Re-expression of Parkin in RhoA-depleted cardiomyocytes restored mitophagy, reduced mitochondrial damage, attenuated cardiomyocyte senescence, and rescued cardiac function both in vitro and in vivo. Finally, we found that patients with idiopathic dilated cardiomyopathy without causal mutations for dilated cardiomyopathy showed reduced cardiac expression of RhoA and Parkin. These results suggest that RhoA promotes Parkin-mediated mitophagy as an indispensable mechanism contributing to cardioprotection in the aging heart.

International audience; Most of the glycosidic aroma precursors in grape consist of diglycosides such as rutinoside. Yeast glycosidases have been extensively studied but their activity is limited to monoglucosidic precursors. Yet, there is no study about application of glycosidases active on rutinoside in grape. In this study, we screened Bacillus isolates for their glycosidase activities on rutin and grape aroma precursors. One Bacillus amyloliquefaciens and one Bacillus licheniformis strains produced extracellular glycosidases, active on both rutin and para-nitrophenol-α-l-rhamnoside. The specific rutinosidic activities were 14 and 9.0 μkat/mg respectively, and supernatants were active on Muscat grape glycosidic aroma precursors. Both strains were able to release monoterpenoids and benzenoids. The most released monoterpenoid in grape pomace was neric acid, with 378 μg/kg and the most released benzenoid was 2-phenylethanol, with 189 μg/kg for B. licheniformis. These glycosidases are interesting tools to target rutinosidic glycosides in grape and can be applied as a new way of valorising grape pomace.

This paper presents the data that estimate the linkages between perceived regulatory support, empathy, moral obligation, social entrepreneurial self-efficacy, perceived social support, and social entrepreneurial intention among Vietnamese students. The scales were adopted from previous studies to develop the questionnaires utilizing a five-Likert scale. The sample collected from 685 undergraduate students from universities in Vietnam. A quantitative approach was utilised to examine the value of data. Specifically, some descriptive statistics was utilized to show the respondents' profiles and characteristics of variables. Cronbach' alpha, exploratory factor analysis and confirmatory factor analysis was used to test the reliability and validity of constructs before estimating path coefficients via structural equational modelling (SEM).

International audience; Lactic acid fermentation is a traditional process to preserve foods and to modify their organoleptic properties. This process is generally conducted in a spontaneous way, allowing indigenous lactic acid bacteria (LAB) of the matrix and of the environment to compete and grow. The aim of this study was to better characterise LAB strains ability to modify aroma profiles in fruit and vegetable matrices, by focusing on two key enzymatic activities: β-glucosidase and alcohol dehydrogenase (ADH). Firstly, 200 LAB isolated from Cambodian and Vietnamese fermented foods were screened for their β-glucosidase activity and duplicate isolates identified through RAPD-PCR analysis were discarded. Thereby, 40 strains were found positive for β-glucosidase using p-nitrophenyl-β-D-glucopyranoside as substrate. Among them, 14 displayed an activity greater than 10 nmol/min/mg dry cell. Thirteen were identified as Lactiplantibacillus (L.) plantarum and one as L. pentosus. Secondly, four strains of different phenotypes for β-glucosidase activity were tested for ADH activity. The highest reduction ability for hexanal and (E)-2-hexenal was obtained for Limosilactobacillus (L.) fermentum V013-1A for which no β-glucosidase activity was detectable. The three other strains (L. plantarum C022-2B, C022-3B, and V0023-4B2) exhibited a lower reduction ability and only for hexanal. Thirdly, mashed tomatoes were fermented with these four strains individually to evaluate their ability to release volatile compounds from the tomato precursors. Fifty-eight volatile compounds were identified and quantified by HS-SPME/GC-MS. Untreated tomatoes were rich in aldehydes. The tomatoes fermented with L. plantarum strains were rich in ketones whereas those with L. fermentum were rich in alcohols. However, for the generation of terpenoids that provide flower and fruit flavours, our screening of β-glucosidase activity was not able to explain the differences among the strains. For ADH activity, L. fermentum exhibited a high activity in fermentation as most of the target aldehydes and ketones disappeared and were replaced by their corresponding alcohols. The L. plantarum strains exhibited a lower activity but with an important substrate-selectivity diversity. A better knowledge of the functionality of each LAB strain in the food matrix will permit to predict and shape the aroma profiles of fermented food.

International audience; Clean label is an important trend in the food industry. It aims at washing foods of chemicals perceived as unhealthy by consumers. Microorganisms are present in many foods (usually fermented), they exhibit a diversity of metabolism and some can bring probiotic properties. They are usually well considered by consumers and, with progresses in the knowledge of their physiology and behavior, they can become very precise tools to produce or degrade specific compounds. They are thus an interesting means to obtain clean label foods. In this review, we propose to discuss some current research to use microorganisms to produce clean label foods with examples improving sensorial, textural, health and nutritional properties.

Diabetes mellitus (DM) causes injury to tissues and organs, including to the heart and kidney, resulting in increased morbidity and mortality. Thus, novel potential therapeutics are continuously required to minimize DM-related organ damage. We have previously shown that dipeptidyl peptidase III (DPPIII) has beneficial roles in a hypertensive mouse model, but it is unknown whether DPPIII has any effects on DM. In this study, we found that intravenous administration of recombinant DPPIII in diabetic db/db mice for eight weeks suppressed the DM-induced cardiac diastolic dysfunctions and renal injury without alteration of the blood glucose level. This treatment inhibited inflammatory cell infiltration and fibrosis in the heart, and blocked the increase in albuminuria by attenuating the disruption of the glomerular microvasculature and inhibiting the effacement of podocyte foot processes in the kidney. The beneficial role of DPPIII was, at least in part, mediated by the cleavage of a cytotoxic peptide, named Peptide 2, which was increased in db/db mice compared with normal mice. This peptide consisted of nine amino acids, was a digested fragment of complement component 3 (C3), and had an anaphylatoxin-like effect determined by the Miles assay and chemoattractant analysis. The effect was dependent on its interaction with the C3a receptor and protein kinase C-mediated RhoA activation downstream of the receptor in endothelial cells. In conclusion, DPPIII plays a protective role in the heart and kidney in a DM animal model through cleavage of a peptide that is a part of C3.

The article represents the experience of Vietnam in the fight against coronavirus and the impact of the COVID-19 pandemic on the country's economy. Historical and logical methods are applied to examine the spread of coronavirus in Vietnam and the government's response to the pandemic. The approach used by the authors us based on the sustainable development concept and distinguishing the concepts of sustainable economic growth and sustainable economic development. The main attention is paid to the analysis of the reasons to allowed Vietnam's quick taking control over the epidemic situation in the country. Based on the materials of international organisations and data from the General Statistics Office of Vietnam, the impact of the pandemic on industry is estimated in terms of its structure. The important roles of the national innovation system and the achievements in digital transformation are revealed in the fight against coronavirus. The opportunities and chanllenges for Vietnam to achieve sustainable economic growth and to join the group of new industrial countries after the coronavirus pandemic are proven on the basis of the Vietnam Research Institute's of the Bank for Investment and Development data and of the World Monetary Fund's forecasts about the prospects of Vietnam's economic growth. By comparison of industrial production for the first six months of 2020 and for the similar period of 2019 the limitations in the development of manufacturing industry are disclosed. The conclusions are made about the resistance of Vietnamese economy and its growth opportunity during and after the coronavirus pandemic. The results of the investigation may be used by researchers studying the problems of economic development and by policy-makers involved in economic planning of developing countries.

Severinia buxifolia (Rutaceae) is often used as a traditional medical plant. The present study was carried out to estimate the effects of solvents (petroleum ether and hexane: ethyl acetate) used in liquid–liquid extraction to total terpenoid content (TTC) and in vitro anti‐inflammatory activity of the extracts obtained from S. buxifolia bark. The results showed that solvent fractionation increased the TTC compared with crude extracts. The hexane: ethyl acetate bark extract fraction (HEF) had the highest TTC (731.48 µg/ml) in comparison with the petroleum ether bark extract fraction (PEF) (564.81 µg/ml) and the crude extract (CE) (184.26 µg/ml). In addition, one of composition of terpenoid of S. buxifolia, namely ursolic acid, was determined by HPLC method from the crude CE and the fractions PEF and HEF: 2.44 μg/g DW, 3.56 μg/g DW and 5.04 μg/g DW, respectively. The samples had an in vitro anti‐inflammatory activity comparable with that of two reference standards (aspirin and indomethacin). Particularly, the HEF fraction had the highest in vitro anti‐inflammatory activity (i.e., albumin denaturation: IC50 = 147.91 μg/mL, heat‐induced hemolysis: IC50 = 159.91 μg/mL, proteinase inhibition: IC50 = 117.72 μg/mL, and lipoxygenase activity: IC50 = 90.45 μg/mL). Besides, the preliminary experiments of this study were conducted to determine the influences of maceration factors (solvent type, temperature, and time) for S. buxifolia bark extract. The TTC ranged from 453.70 to 842.59 mg linalool/g DW, and the extraction yield from 2.40% to 5.120% in all extracts. Based on TTC and EY, the hexane: acetone mixture is recommended as the optimal solvent to obtain the crude bark extract (CE) at 46°C for 24 hr of maceration. Extracts of S. buxifolia bark are a promising source for the treatment of inflammatory diseases., Solvent fractionation was found to increase the TTC compared with crude extracts based on colorimetric assay using linalool as standard reagent. The samples were indicated to have in vitro anti‐inflammatory comparable with two reference standards (aspirin and indomethacin) based on the inhibition of albumin denaturation, proteinase activity, heat‐induced hemolysis, and lipoxygenase assay.

This paper presents the dataset that estimate the effect of factors on students' satisfaction and their academic performance. The questionnaire with a five-Likert scale ware adapted and developed from prior researches. The sample consisted of 430 fulfilled respondents using stratified random sampling, which recruited from eight private universities in the North of Vietnam. A quantitative method was employed to examine the data. Cronbach's Alpha, Exploratory Factor Analysis, Confirmatory Factor Analysis were utilized to test the reliability and validity of each variable as well as the model fit. Then, the structural equation modeling was used to estimate path coefficients, which can serve as a good reference for further researches.

International audience; Fermented Asian foods have recently gained popularity, crossing from Asian communities to mainstream markets, in many western countries. However, less attention has been paid to the safety of these foods. In South-East Asia, fermented products are still produced following traditional methods. Therefore, consumers are not confident in their microbial safety. The challenges awaiting fermentation in South-East Asia are thus to improve safety and quality in a sustainable system producing tasty and typical fermented products. A possible solution could be the use of starter cultures able to increase the safety of food stuffs. Starters could also help to standardize the production process and reduce ripening times. The current review addresses the role of lactic acid bacteria on the microbiological and chemical safety of Asian legume based fermented products. In particular, their role in the reduction of anti nutritional compounds (e.g. phytates) and protein allergenicity is discussed. Moreover, starters can inihibit the development of amino acid-decarboxylating microbes preventing the accumulation of biogenic amines, they can also be useful to reduce the accumulation of mycotoxins and inhibit pathogens’ development. Finally, their role in the degradation of pesticides is analyzed.

Objective: To evaluate the infections that caused by Methicillin-resistant Staphylococcus aureus and the value of the tests to detect Methicillin-resistant Staphylococcus aureus. Subjects and Methods: Used routine techniques to culture and isolate S.aureus, test the antibiotic sensitivity by Kirby-Bauerr, determination the Methicillin-resistant Staphylococcus aureus by Oxacillin and cefoxitin disc and PCR in identified the mecA gene Staphylococcus aureus. Results: The rate of Staphylococcus aureus isolated is highest which isolated from pus specimens (55.06%). In 267 strains of Staphylococcus aureus isolated in the Department of Microbiology, Hue Central Hospital the Methicillin resistance Staphylococcus aureus was 61.42%. The level of antibiotic resistant strains of Methicillin-resistant Staphylococcus aureus is higher than that in Methicillin-sensitive strains. Conclusion: Cefoxitin 30 microg disk diffusion method to detect Methicillin resistance is effective for determinate Methicillin-resistant Staphylococcus aureus (sensitivity and specificity are all 100.00%). Key words: Staphylococcus aureus Methicillin-resistant.

Despite the iconic association of palms with semi-arid regions, most are introduced and can invade natural areas. Along the San Diego River (San Diego, California, USA), the introduced Canary Island date palm (Phoenix canariensis) forms dense patches among native riparian shrubs like arroyo willow (Salix lasiolepis). The structural differences between the palm and native shrubs are visually obvious, but little is known about palm’s effects on the ecosystem. We tested for the effects of the palm on a riparian invertebrate community in June 2011 by comparing the faunal and environmental variables associated with palm and willow canopies, trunks and ground beneath each species. The palm invertebrate community had lower abundance and diversity, fewer taxa feeding on the host (e.g., specialized hemipterans), and more taxa likely using only the plant’s physical structure (e.g., web-builders, oak moths, willow hemipterans). There were no observed effects on the ground-dwelling fauna. Faunal differences were due to the physical and trophic changes associated with palm presence, namely increased canopy density, unpalatable leaves, trunk rugosity, and litter accumulations. Palm presence and resulting community shifts may have further ecosystem-level effects through alteration of physical properties, food, and structural resources. These results were consistent with a recent study of invasive palm effects on desert spring arthropods, illustrating that effects may be relatively generalizable. Since spread of the palm is largely localized, but effects are dramatic where it does occur, we recommend combining our results with several further investigations in order to prioritize management decisions.

Bacillus subtilis 168 is resistant to phenolic acids by expression of an inducible enzyme, the phenolic acid decarboxylase (PadC), that decarboxylates these acids into less toxic vinyl derivatives. In the phenolic acid stress response (PASR), the repressor of padC , PadR, is inactivated by these acids. Inactivation of PadR is followed by a strong expression of padC . To elucidate the functional interaction between PadR and the padC promoter, we performed (i) footprinting assays to identify the region protected by PadR, (ii) electrophoretic mobility shift assays (EMSAs) with a modified padC promoter protected region to determine the interacting sequences, and (iii) random mutagenesis of padR to identify amino acid residues essential for the function of PadR. We identified an important consensus dyad sequence called IR1-2 (ATGT-8N-ACAT) overlapping a second dyad element (GTGT-8N-ACAT) that we named dIR1-2bis. The entire dIR1-2bis/IR1-2 sequence permits binding of two PadR dimers in EMSAs, which may be observed for bacteria grown under noninduced conditions where the padC promoter is completely repressed. Three groups of modified PadRs giving a PASR phenotype were characterized in vivo . The DNA sequences of certain mutant padR alleles indicate that important residues are all located in the region containing the coiled-coil leucine zipper domain that is involved in dimerization. These substitutions reduce the affinity of PadR binding to the padC promoter. Of particular interest are residue L128, located at the center of the putative coiled-coil leucine zipper domain, and residue E97, which is conserved among all PadRs.

In this paper we apply importance sampling (IS) for efficient performance evaluation of turbo codes over Rayleigh fading channels. Our approach is based on the most probable error path (MPEP) method which shifts the input probability density function (pdf) to the mode of the optimal biased distribution where most probable errors are located. In particular, we show how to bias the pdf of the AWGN process in order to maximize the computational efficiency gain. It is demonstrated that the proposed method requires much smaller sample sizes to achieve the same accuracy required by a conventional MC estimator.

In Bacillus subtilis , several phenolic acids specifically induce expression of padC , encoding a phenolic acid decarboxylase that converts these antimicrobial compounds into vinyl derivatives. padC forms an operon with a putative coding sequence of unknown function, yveFG , and this coding sequence does not appear to be involved in the phenolic acid stress response (PASR). To identify putative regulators involved in the PASR, random transposon mutagenesis, combined with two different screens, was performed. PadR, a negative transcriptional regulator of padC expression, was identified. padR is not located in the vicinity of padC , and the expression of padR is low and appears constitutive. This is in contrast with what occurs in other gram-positive bacteria, in which padR is autoregulated and induced by phenolic acids. Further screening of the transposon library failed to identify genes other than padR involved in the PASR. Modest inactivation of padR by phenolic acids was obtained in recombinant Escherichia coli expressing padC and padR , and this translates into induction of decarboxylase activity. Gel shift promoter binding assays performed with and without MgCl 2 , and with and without phenolic acids, demonstrated that phenolic acids were able to abolish the binding of PadR to the yveFG - padC promoter in the absence of MgCl 2 . Altogether, our results indicate that (i) PadR is inactivated directly by phenolic acids in vitro, (ii) inhibition of PadR in response to phenolic acids may occur without the need for a sensor-like effector in B. subtilis , and (iii) phenolic acids are able to modulate PadR activity in E. coli in the absence of any additional effector.

The design of space-time turbo trellis codes (ST Turbo TC) for improving the bandwidth efficiency and the reliability of wireless data networks, which is based on the turbo structure, has been proposed in the literature. However, like other turbo based coding schemes, the fundamental problems with the ST Turbo TC decoder are its complexity and decoding delay. In some cases the decoding delay may be so long that the use of ST Turbo TC system is unattractive for time sensitive applications. The aim of this paper is to propose a simplified ST Turbo TC decoder using the sliding window technique in order to achieve memory savings and reduce decoding delay. In particular, we consider the performance of QPSK ST Turbo TC schemes on fast fading channels for various system parameters. Different window sizes are employed and investigated. Through computer simulation, the optimum window sizes are defined for different system parameters.

To improve the performance of wireless communication systems, bandwidth efficient space-time turbo trellis codes (ST turbo TC), which is based on the turbo structure, has been proposed in the literature. In this paper, we analyze the performance of a fixed-point ST Turbo TC decoder using sliding window algorithm. In particular, we present the investigation of bit-width optimization for a 4-state QPSK ST Turbo TC decoder based on the symbol-by-symbol (SBS) logarithm-maximum a posteriori (Log-MAP) algorithm on fast fading channels. The decoder structure utilizes a sliding window algorithm for reducing memory requirements and decoding delay. We show that ST Turbo TC is feasible for finite word length representation without significant degradation in the frame error rate (FER) performance. Through computer simulation, the optimum word length configurations are determined for all quantities external and internal to the ST Turbo TC decoder.

In this paper, we illustrate the use of importance sampling (IS) for efficient simulation of Turbo Codes over additive white Gaussian noise (AWGN) channels. In particular, we show how to bias the probability density function (pdf) of the AWGN process using the most probable error path (MPEP) method in order to maximize the computational efficiency gain. The new noise pdf is designed based on the optimal biased distribution where zero variance estimator can be achieved. It is demonstrated that the proposed method requires much smaller sample sizes to achieve the same accuracy required by a conventional MC estimator.