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The nanocomposite of graphene oxide and silver nanoparticles with uniform particle distribution was successfully green synthesized for bioactive assessment and hydrogen peroxoide electro-sensing application.

The plant Morinda citrifolia L. (Noni) has been the subject of several recent research due to its positive impact on the treatment and prevention of a variety of diseases. Noni fruits contain a variety of phytochemicals, including flavonoid, polyphenol, and triterpenoid saponin. This study aimed to determine the best pre-treatment (including blanching, soaking in ascorbic acid solution and metabisulfite solution) and air-drying temperature (50, 60, 70, and 80 °C) to maximize the total polyphenol content (TPC), flavonoid content (TFC), and triterpenoid saponin contents (TSC) of the resultant Noni fruit powder. The results revealed that pre-soaked Noni fruit samples in ascorbic acid or metabisulfite solution before air-drying at 60 °C were beneficial in preserving TPC, TFC, and TSC. TPC, TFC, and TSC losses increased as drying temperatures (70 and 80 °C) rose. The optimum sample was held at five different relative humidity conditions until they attained weight equilibrium. The results indicated that the sorption isotherm curve of the Noni powder was the sigmoid shape and fitted with the BET and GAB models.

As a response to the coronavirus disease 2019 (COVID-19) pandemic, Vietnam enforced strict quarantine, contact tracing and physical distancing policies resulting in one of the lowest numbers of individuals infected with severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) globally. This study aimed to determine the prevalence of SARS-CoV-2 antibody positivity among high-risk populations in Vietnam. A prevalence survey was undertaken within four communities in Vietnam, where at least two COVID-19 cases had been confirmed. Participants were classified according to the location of exposure: household contacts, close contacts, community members, and healthcare workers (HCWs) responsible for treating COVID-19 cases. Participants completed a baseline questionnaire and SARS-CoV-2 IgG antibodies were quantified using a commercial assay. A total of 3049 community members and 149 health care workers consented to the study. Among 13 individuals who were seropositive (0.4%), five household contacts (5/27, 18.5%), one close contact (1/53, 1.9%), and seven community members (7/2954, 0.2%) had detectable SARS-CoV-2 antibodies. All HCWs were negative for SARS-CoV-2 antibodies. Participants were tested a median of 15.1 (interquartile range from 14.9 to 15.2) weeks after exposure. Our study found a low prevalence of SARS-CoV-2 antibodies in high-risk communities and healthcare workers in communities in Vietnam with known COVID-19 cases.

Background: As a response to the coronavirus disease 2019 (COVID-19) pandemic, Vietnam enforced strict quarantine, contact tracing and physical distancing policies. By December 2020, this strategy resulted in one of the lowest numbers of individuals infected with severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) cases globally. This study aimed to determine the prevalence of SARS-CoV-2 antibody positivity among high-risk populations in Vietnam. Methods: A prevalence survey was undertaken within four communities in northern and central Vietnam, where at least two COVID-19 cases had been confirmed. Participants were classified according to the location of exposure: household contacts, close contacts, community members, and healthcare workers (HCWs) responsible for treating COVID-19 cases. Participants completed a baseline questionnaire that evaluated exposure history. SARS-CoV-2 IgG antibodies were quantified using a commercially available assay. Results: 3056 community members and 149 health care workers provided consent to participate. Among enrolled community members, 27 (0·9%) were household contacts and 53 (1·7%) were close contacts. Serology was performed in 3034 individuals. Among 13 individuals who were seropositive (0·4%), five household contacts (5/27, 18·5%), one close contact (1/53, 1·9%), and seven community members (7/2954, 0·2%) had detectable SARS-CoV-2 antibodies. All HCWs were negative for SARS-CoV-2 antibodies. Participants were tested a median of 15·1 (interquartile range 14·9 to 15·2) weeks after exposure. Conclusion: The presence of SARS-CoV-2 antibodies in high-risk communities and healthcare workers was low in communities in Vietnam with known COVID-19 cases. The public health response to the COVID-19 pandemic in Vietnam has been effective in limiting community transmission of SARS-CoV-2. Funding Statement: This project was supported by a grant funded by the Australian Department of Foreign Affairs and Trade, awarded in conjunction with the Australian National Health and Medical Research Council (APP1153346). Declaration of Interests: None declared. Ethics Approval Statement: Ethical approval was obtained from the Human Research Ethics Committees of the University of Sydney (HREC 2020/415) and Biomedical Research Ethics Committee of the National Hospital for Tropical Diseases (No. 10/HDDD-NDTU and No. 18/HDDD-NDTU). Consent was documented electronically using a tablet computer. In accordance with local expectations, all COVID-19 patients and other participants were provided with monetary compensation for their participation, equivalent to approximately US$4·30 and US$2·20, respectively.

International audience; GNSS brings more signals and more satellites to improve positioning services. This paper introduces data fusion from multiple Global Navigation Satellite System (GNSS) constellations. In fact, some failures in satellite's signals negatively impact the quality of positioning. For this purpose, this paper presents the robust Extended Kalman Filter (robust-EKF) to eliminate the outliers and de-noising method based on the Long Short-Term Memory (LSTM). The algorithms are tested using GPS, Galileo and GLONASS data corresponding to base station ABMF in Guadeloupe. Robust combination of GPS, Galileo, and GLONASS data improve the position accuracy from 41.0% to 95.0% compared to the use of independent systems and by about 84.0% compared to the non-robust combination of GPS, Galileo, and GLONASS data. In particular, the position precision improves significantly using the method LSTM-EKF by about 74.0% compared to the robust-EKF.

This paper presents data fusion from multiple Global Navigation Satellite System (GNSS) constellations. GNSS brings more signals and more satellites to improve the accuracy of user’s position. However, multiple failures in satellite’s signals sometimes negatively impact the determination of the user’s position and should be considered. For this purpose, the present paper provides robust Extended Kalman Filter (robust-EKF) to eliminate the outliers. The algorithms are tested by using GPS, Galileo and GLONASS data corresponding on data from base station GRAC in Grasse, France. Applying the robust-EKF method as well as the robust combination of GPS, Galileo, and GLONASS data improves the position accuracy by about 30.0%, 20.7%, and 90% compared to the use of GPS data only, Galileo data only, and GLONASS data only, respectively, and by about 67% compared to the nonrobust combination of GPS, Galileo, and GLONASS data.

We report that whereas firms with high earnings distributions tend to have low‐to‐moderate growth (consistent with conventional theory), firms with low earnings distributions run the range between high and low performers. We interpret our findings for firm growth and payout policy in relation to the firm's location on the Boston Consulting Group (BCG) matrix that combines high/low growth with high/low market share. Our findings suggest that the market has difficulty in distinguishing between these types of firms. A concern is that investor preferences as an outcome may be focussed on dividend‐paying firms at the expense of younger growing firms in need of retained earnings.

Objective— Previous genetic lineage tracing studies showed that Sox10 + cells differentiate into vascular mural cells, limited to neural crest–derived blood vessels in craniofacial tissues, aortic arch, pulmonary arch arteries, brachiocephalic, carotid arteries, and thymus. The purpose of this study was to investigate the contribution of Sox10 + cells to the vascular development in other tissues and organs and their relationship with neural crest. Approach and Results— Using genetic lineage tracing technique based on Cre/LoxP system, we examined blood vessels in the adult organs of the mice expressing Sox10-Cre/Rosa-LoxP-red fluorescent protein or Wnt1-Cre/Rosa-LoxP-red fluorescent protein by immunohistological analysis. In addition to previously reported tissues and organs derived from neural crest, we showed that Sox10 + cells also contributed to vascular mural cells in the lung, spleen, and kidney, which are derived from non-neural crest origin as evidenced by red fluorescent protein-negative blood vessels in these 3 organs of Wnt1-Cre/Rosa-LoxP-red fluorescent protein mice. Conclusions— This study demonstrates that Sox10 + cells contribute to pericytes and smooth muscle cells in most parts of the body, including those from neural crest and non-neural crest, which has significant implications in vascular remodeling under physiological and pathological conditions.

In the recent years, multi-constellation and multi-frequency have improved the positioning precision in GNSS applications and significantly expanded the range of applications to new areas and services. However, the use of multiple signals presents advantages as well as disadvantages, since they may contain poor quality signals that negatively impact the position precision. The objective of this study is to improve the Single Point Positioning (SPP) accuracy using multi-GNSS data fusion. We propose the use of robust-Extended Kalman Filter (referred to as robust-EKF hereafter) to eliminate outliers. The robust-EKF used in the present work combines the Extended Kalman Filter with the Iterative ReWeighted Least Squares (IRWLS) and the Receiver Autonomous Integrity Monitoring (RAIM). The weight matrix in IRWLS is defined by the MM Estimation method which is a robust statistics approach for more efficient statistical data analysis with high breaking point. The RAIM algorithm is used to check the accuracy of the protection zone of the user. We apply the robust-EKF method along with the robust combination of GPS, Galileo and GLONASS data from ABMF base station, which significantly improves the position accuracy by about 84% compared to the non-robust data combination. ABMF station is a GNSS reception station managed by M&eacute, t&eacute, o-France in Guadeloupe . Thereafter, ABMF will refer to the acronym used to designate this station. Although robust-EKF demonstrates improvement in the position accuracy, its outputs might contain errors that are difficult to estimate. Therefore, an algorithm that can predetermine the error produced by robust-EKF is needed. For this purpose, the long short-term memory (LSTM) method is proposed as an adapted Deep Learning-Based approach. In this paper, LSTM is considered as a de-noising filter and the new method is proposed as a hybrid combination of robust-EKF and LSTM which is denoted rEKF-LSTM. The position precision greatly improves by about 95% compared to the non-robust combination of data from ABMF base station. In order to assess the rEKF-LSTM method, data from other base stations are tested. The position precision is enhanced by about 87%, 77% and 93% using the rEKF-LSTM compared to the non-robust combination of data from three other base stations AJAC, GRAC and LMMF in France, respectively.

Although a good deal of research effort has been allocated to understanding the time-series volatility of stock returns – as both market (or systematic) volatility and idiosyncratic (or non-systematic) volatility – the relationship of such volatility with cross-sectional volatility or dispersion of outcomes is sparse. Nevertheless, the quest to understand one must involve the quest to understand the other. In this paper, we investigate the dynamic of the dispersion of return outcomes in generating a portfolio’s expected return outcome. We find that changes in the level of cross-sectional volatility have highly significant implications for portfolio performances and the notion of risk.

Pleistocene aquifer is exploited for many purposes, including irrigation, domestic, production, and livestock use in Phu My town, Ba Ria – Vung Tau province. Groundwater Quality Index (GWQI) method combined with Geographic Information System (GIS) foundation is applied to determine the spatial variation as well as the suitability of groundwater in the study area. Water quality parameters in this study include pH, TDS, total hardness, Cl-, F-, NH4+, NO3-, SO42-, Pb2+, and Fe2+ were selected for analyzing from 17 monitoring wells in dry and wet seasons in 2017. The results indicate that water quality parameters such as Cl-, F-, NH4+-N, Pb2+ và Fe2+ exceed the maximum allowable levels by National Technical Regulation on Groundwater Quality. The groundwater quality, according to GWQI analysis results, shows that indicate 88% and 94% of the monitoring wells are from “good” to “excellent” type in the dry and wet seasons, respectively. The number of wells that have water quality from “poor” to “water unsuitable for drinking purpose” varies between the dry and wet seasons. Corresponding with the GWQI map, it shows that the area with good quality groundwater accounts for 98% of the total study area (331.44 km2) in the dry season and 94.5% of the study area (319.58 km2) in the wet season.

Ultralight graphene-based cellular elastomers are found to exhibit nearly frequency-independent piezoresistive behaviors. Surpassing the mechanoreceptors in the human skin, these graphene elastomers can provide an instantaneous and high-fidelity electrical response to dynamic pressures ranging from quasi-static up to 2000 Hz, and are capable of detecting ultralow pressures as small as 0.082 Pa.

•CEO power-firm performance relationship is conditional on BCG classification.•CEO power has a positive influence on the performance of star and question mark firms.•CEO power has a negative influence on the performance of cash cow firms.•Market valuation of CEO power is also conditional on BCG classification.

We analyse the determinants of equity agency costs for the top 500 Australian listed firms. Data are collected over four one-year periods (2004, 2005, 2010 and 2011) and analysed using both pooled OLS regression and two stage least squares regression within a random effects panel data model. Analysis covers the full four-year period, the pre global financial crisis (GFC) sub-period (2004 and 2005) and the post GFC sub-period (2010 and 2011). Shareholding, board characteristics and debt financing are found to have an impact on agency costs though there is evidence of some change in these relations with the onset of the GFC, particularly with respect to the impact of insider ownership and board size.

Previous genetic lineage tracing studies showed that Sox10Using genetic lineage tracing technique based on Cre/LoxP system, we examined blood vessels in the adult organs of the mice expressing Sox10-Cre/Rosa-LoxP-red fluorescent protein or Wnt1-Cre/Rosa-LoxP-red fluorescent protein by immunohistological analysis. In addition to previously reported tissues and organs derived from neural crest, we showed that Sox10This study demonstrates that Sox10

A simple treatment of a polypyrrole (PPy) film with sodium hydroxide (NaOH) solutions reduces the conductivity (i.e., increased the resistance) and makes the film heat sensitive in the infrared (IR) spectrum with wavelength from 2.5 to 15.4 μm. The IR sensitivity increases with increasing treatment time in NaOH solutions and increasing exposed area to the radiation. The temperature coefficient of resistance, α, quantifying the sensitivity to IR, of the NaOH-treated PPy is comparable with that of silicon and other conventional materials. The reduction and recovery of resistance due to IR on/off exposure exhibit a tβ dependence, where t is the time and β is determined to be around 0.5. This implies that the response of the material is controlled by diffusion of heat flux into and out of the sample. It is also observed that thermal ageing of the NaOH-treated PPy film enhances the IR sensitivity. The sensing response of the treated films is observed beyond the thermal IR region to ultraviolet–visible wavelengths. Thus, the NaOH-treated PPy appears to be a broadband sensing material. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012

Our ears often simultaneously receive various sound sources (speech, music, noise . . .), but we can still listen to the intended sound. A system of speech recognition must be able to achieve the same intelligent level. The problem is that we receive many mixed (combined) signals from many different source signals, and would like to recover them separately. This is the problem of Blind Source Separation (BSS). In the last decade or so a method has been developed to solve the above problem effectively, that is the Independent Component Analysis (ICA). There are many ICA algorithms for different applications. This report describes our application to sound separation when there are more sources than mixtures (underdetermined case). The results were quite good.

In Vietnam, vaccination has played a crucial role in the national strategy for the prevention and control of H5 highly pathogenic avian influenza (HPAI). This study aimed to evaluate antibody responses of immunologically naïve domestic ducks to H5N1 avian influenza vaccine currently used in the national mass vaccination program of Vietnam. Blood samples of 166 ducks reared on smallholder farms were individually collected at three sampling time points, namely, right before vaccination, 21 days after primary vaccination, and 21 days after booster vaccination. Vaccine-induced antibody titers of duck sera were measured by the hemagglutination inhibition assay. Temporal differences in mean antibody titers were analyzed using the generalized least-squares method. No sampled ducks showed anti-H5 seropositivity pre-vaccination. The geometric mean titer (GMT) of the vaccinated ducks was 5.30 after primary vaccination, with 80% of the vaccinated ducks showing seropositivity. This result indicates that the immunity of duck flocks met the targets of the national poultry H5N1 HPAI mass vaccination program. GMT and seropositive rates of the ducks were 6.48 and 96.3%, respectively, after booster vaccination, which were significantly higher than those after primary vaccination. Flock-level seroprotection rate significantly increased from 68% to 84.7%, whereas variability in GMT titers decreased from 34.87% to 26.3%. This study provided important information on humoral immune responses of ducks to the currently used H5N1 vaccine under field conditions. Our findings may help guide veterinary authorities in planning effective vaccine protocols for the prevention and control of H5N1 in the target poultry population.

This paper overviews some recent S&T innovations in smart materials and structures at the Australian Defence Science and Technology Organisation (DSTO) under a Corporate Enabling Research Program (CERP) on Signatures, Materials and Energy. The CERP program includes development and transitioning of technology across the maritime, air and land domains, with the major focus of the smart materials program component being to increase the safety, availability and maintainability of Defence assets. Three specific examples are provided of the smart materials and structures program, ranging across the spectrum of technology readiness from new concept phase to technology transitioning, viz.: (i) Advances in smart sensing for prognostics-based platform management; (ii) Fabrication of nanostructured and ultrafine grained materials through top-down severe plastic deformation processing of bulk materials; (iii) Innovative application of carbon nanotubes/conducting polymers as artificial muscles for low-power propulsion and control of small autonomous underwater systems. In each case, the DSTO effort is underpinned by strong university or industry linkages to deliver challenging interdisciplinary S&T.

Swimming-type robotic fish are being developed as mobile sensor platforms that have the potential to outperform existing underwater vehicles in terms of manoeuvrability, miniaturisation and silent operation. Conducting polymer actuators are potential candidates for propelling a flapping tail fin for a robotic fish. This study introduces a method for directly measuring the thrust force generated by a polypyrrole (PPy) powered tail fin. The effects of voltage stimulus (waveform shape and frequency) and tail fin shape on the thrust force were determined. A square wave voltage input was shown to generate the highest thrust forces as fast bending actuation was induced. The thrust force tended to decrease at higher operating frequencies as a result of the reduced actuation occurring in the PPy layers. Increases in the tail fin area tended to lower the frequency where the peak in thrust force was achieved. Tail fin shape was also shown to be important to the force-frequency behaviour. When attached to an untethered robotic fish, the swimming speed tended to increase with increasing voltage input frequency. There was also an optimum frequency that enabled the fastest acceleration from rest that happened to be higher than the frequency that gave the peak thrust force. This was presumed to be due to the complicated swimming behaviour involving the side-to-side movement of the fish nose at low flap frequencies. The study provides valuable insight into the means for tailoring polymer actuator performance to achieve maximum fish swimming speeds. Copyright © 2010 Society of Chemical Industry

Electrochemical gas generation and consumption at carbon nanotube (CNT) electrodes was investigated as a means of powering pneumatic actuators. Two different types of carbon nanotubes were evaluated in a variety of aqueous electrolytes. Chlorine gas generation from aqueous sodium chloride electrolyte was found to be the most suitable system investigated, based on the ability to electrochemically reduce the gas generated. Carbon nanotubes produced by different techniques exhibit different chlorine oxidation and reduction capabilities with HiPCO nanotubes showing a higher electrochemical activity than nanotubes made by the laser ablation method. In a closed electrochemical cell fitted with a pressure transducer, the oxidation of Cl − ions to Cl 2 gas was ∼40% efficient based on the charge passed. In contrast, the reduction of Cl 2 gas pressure was almost 100% efficient, although the exact mechanisms of gas reduction were complicated by side reactions and kinetic processes. A carbon nanotube electrode of 2.4 mm 3 was capable of producing 0.5 cm 3 of gas at atmospheric pressure, or an increase of up to 50 kPa in a closed cell depending upon the headspace volume. The work capacity based on the size of the electrode was 5000 kJ/m 3 , which is nearly two orders of magnitude larger than other low voltage electrochemical actuators.

Lymphatic research signifies a field of rapid progression in recent years. Though lymphatic dysfunction has been found in a myriad of disorders, to date, few effective treatments are available for lymphatic diseases. It is therefore urgent to develop new experimental approaches and therapeutic protocols. The cornea offers an ideal site for lymphatic research due to its transparent nature, accessible location and lymphatic-free but –inducible features. Moreover, we have recently discovered that corneal lymphatic vessels develop luminal valves as lymphangiogenesis proceeds. This tissue thus provides an optimal tool to study both lymphangiogenesis and valvulogenesis upon a pathological insult. In this paper, we show that the modified Prox-1-GFP mice carrying wildtype C57BL/6 background provide a valuable tool for intravital imaging of corneal lymphatic vessels and valves and can be used to study pathological lymphangiogenesis induced by various insults. Further, we demonstrate the multifaceted dynamics of lymphangiogenesis and valvulogenesis associated with transplantation, from the initiation to regression phases and report several novel and critical phenomena and mechanisms that cannot be detected by conventional ex vivo approaches. Further investigation holds the great potential for divulging new mechanisms and therapeutic strategies for lymphangiogenesis and lymphangiogenesis-related diseases at various stages and inside or outside the eye.

This paper examines the interaction between the largest shareholder and dividend policy in a sample of 8,279 listed firms drawn from 37 countries. We find that firms are more likely to pay dividends when profitability is high, debt is low, investment opportunities are limited or when the largest shareholder is not an insider. Further, the magnitude of dividend payout tends to be smaller when the largest shareholder is either an insider or a financial institution. It is also apparent that largest shareholding and dividend payout are related and that, consistent with the extant literature, legal system does matter in dividend policy decisions.