In this study, novel biogenic silver (AgNPs) and gold nanoparticles (AuNPs) were developed using a green approach with Ganoderma lucidum (GL) extract. The optimization of synthesis conditions for the ...best outcomes was conducted. The prepared materials were characterized and their applicability in catalysis, antibacterial and chemical sensing was comprehensively evaluated. The GL-AgNPs crystals were formed in a spherical shape with an average diameter of 50 nm, while GL-AuNPs exhibited multi-shaped structures with sizes ranging from 15 to 40 nm. As a catalyst, the synthesized nanoparticles showed excellent catalytic activity (>98% in 9 min) and reusability (>95% after five recycles) in converting 4-nitrophenol to 4-aminophenol. As an antimicrobial agent, GL-AuNPs were low effective in inhibiting the growth of bacteria, while GL-AgNPs expressed strong antibacterial activity against all the tested strains. The highest growth inhibition activity of GL-AgNPs was observed against B. subtilis (14.58 ± 0.35 mm), followed by B. cereus (13.8 ± 0.52 mm), P. aeruginosa (12.38 ± 0.64 mm), E. coli (11.3 ± 0.72 mm), and S. aureus (10.41 ± 0.31 mm). Besides, GL-AgNPs also demonstrated high selectivity and sensitivity in the colorimetric detection of Fe3+ in aqueous solution with a detection limit of 1.85 nM. Due to the suitable thickness of the protective organic layer and the appropriate particle size, GL-AgNPs validated the triple role as a high-performance catalyst, antimicrobial agent, and nanosensor for environmental monitoring and remediation.
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•Biogenic AgNPs and AuNPs were prepared using Ganoderma lucidum extract.•Both MNPs possessed excellent catalytic activity for the reduction of 4-nitrophenol.•AgNPs showed strong antibacterial activity against several bacterial strains.•The AgNPs-based probe can accurately determine Fe3+ in water with LOD of 1.85 nM.
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•Cocatalysts in TiO2-based photocatalysts are highlighted for solar hydrogen production.•Design strategies of cocatalysts in TiO2-based photocatalysts are presented ...systematically.•Enhancements are attributed to manipulating the charge separation and surface reactions.•Challenges and perspectives of cocatalysts in TiO2-based photocatalysts are proposed.
TiO2-based photocatalysts have been maintained as the most prominent candidate for solar-driven hydrogen (H2) evolution over the past decades. However, poor separation of generated electron-hole pairs has been considered the bottle-neck issue, restricting the TiO2 activity. Coupling a TiO2 photocatalyst to cocatalyst(s) turns out to be the ideal strategy to suppress the charge recombination and offer robust active centres, boosting the H2 evolution performance. This review aims at providing the frontier investigations of cocatalysts-integrated TiO2 for photo-induced H2 evolution. Four types of cutting-edge development of cocatalysts, including metal (noble metal, non-noble metal, bimetallic), metal sulfides and metal phosphides, 2D-MXenes, and dual materials-based cocatalysts, have been successfully highlighted and discussed. The systematically provided cocatalysts, which remarkably promote the charge separation and facilitate the surface reactions, bring out a roadmap to inspire the preparation of superior TiO2-based materials for H2 evolution shortly. We expect this review could provide enriched information to tailor the TiO2 supported active sites of cocatalysts for highly photo-induced H2 evolution.
Abstract
Most of the existing chest X-ray datasets include labels from a list of findings without specifying their locations on the radiographs. This limits the development of machine learning ...algorithms for the detection and localization of chest abnormalities. In this work, we describe a dataset of more than 100,000 chest X-ray scans that were retrospectively collected from two major hospitals in Vietnam. Out of this raw data, we release 18,000 images that were manually annotated by a total of 17 experienced radiologists with 22 local labels of rectangles surrounding abnormalities and 6 global labels of suspected diseases. The released dataset is divided into a training set of 15,000 and a test set of 3,000. Each scan in the training set was independently labeled by 3 radiologists, while each scan in the test set was labeled by the consensus of 5 radiologists. We designed and built a labeling platform for DICOM images to facilitate these annotation procedures. All images are made publicly available in DICOM format along with the labels of both the training set and the test set.
This study investigated methyl orange (MO) dye adsorption using three biochars produced from agro-waste and invasive plants; the latter consisted of wattle bark (BA), mimosa (BM), and coffee husks ...(BC). BC had the lowest specific surface area (2.62 m2/g) compared to BA (393.15 m2/g) and BM (285.53 m2/g). The adsorption efficiency of MO was stable at pH 2–7 (95%–96%), whilst it had reduced stability at pH 7–12. Between 0 and 30 min, MO adsorption efficiency was >82%, and at 120 min, representative adsorption equilibrium had occurred. The maximum adsorption capacity of the biochars was 12.3 mg/g. The underlying adsorption mechanisms of the three biochars were governed by electrostatic adsorption and pore diffusion. There was an abundance of active sites for adsorption in BA and BM, while chemical adsorption appeared to be more vital for BC, as it contained more functional groups on its surface. The highest MO adsorption efficiency occurred with BM. BC was not recommended for MO removal, as it was observed to stain the water when a dose exceeding 5.0 g/L was utilized.
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•Biochars were successfully derived from agro-waste and invasive plants.•After only 30 min the methyl orange adsorption efficiency on biochar was more than 82%.•The adsorption equilibrium was established at 120 min.•The highest adsorption occurred with biochar from mimosa.
In this study, biochar derived from spent coffee grounds (SCGB) was used to adsorb norfloxacin (NOR) in water. The biochar properties were interpreted by analysis of the specific surface area, ...morphology, structure, thermal stability, and functional groups. The impacts of pH, NOR, and ion's present on SCGB performance were examined. The NOR adsorption mode of SCGB is best suited to the Langmuir model (R2 = 0.974) with maximum absorption capacity (69.8 mg g−1). By using a Response Surface Method (RSM), optimal adsorption was also found at pH of 6.26, NOR of 24.69 mg L−1, and SCGB of 1.32 g L−1. Compared with biochars derived from agriculture such as corn stalks, willow branches, potato stem, reed stalks, cauliflower roots, wheat straw, the NOR adsorption capacity of SCGB was 2–30 times higher, but less than 3–4 times for biochars made from Salix mongolica, luffa sponge and polydopamine microspheres. These findings reveal that spent coffee grounds biochar could effectively remove NOR from aqueous solutions. Approaching biochar derived from coffee grounds would be a promising eco-friendly solution because it utilizes solid waste, saves costs, and creates adsorbents to deal with emerging pollutants like antibiotics.
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•Norfloxacin was removed using biochar derived from spent coffee grounds (SCGB).•pH significantly influenced the Norfloxacin (NOR) adsorption of the SCGB.•Based on Langmuir model, the maximum absorption capacity was 69.8 mg g−1 at pH 6.•The adsorption process was optimized by using the response surface methodology.•Optimal adsorption conditions were achieved at pH of 6.26 and SCGB of 1.32 g L−1.
Three new sulfated naphthopyrone derivatives namely delicapyrons F–H (1–3) and two new sulfated anthraquinone derivatives namely delicaquinons A (4) and B (5), together with ...6-methoxycomaparvin-5-methylether-8-O-sodium sulfate (6), 6-methoxycomaparvin-8-O-sodium sulfate (7), comaparvin-8-O-sodium sulfate (8), and 3-propyl-1,6,8-trihydroxy-9,10-anthraquinone-6-O-sodium sulfate (9) were isolated from the Vietnamese crinoid Comanthus delicata. Their chemical structures were elucidated by extensive analysis of the one dimensional (1D) and 2D-NMR, high resolution electrospray ionization quadrupole time-of-flight (HR-ESI-QTOF) mass spectra as well as calculation of optical rotation. In addition, significant cytotoxicity was observed for 6 against LNCaP (prostate cancer) cell line with IC50 value of 20.29 ± 2.43 µM, whereas moderate or weak cytotoxic effects were observed for 1–3 and 5–8 on SK-Mel-2 (melanoma) cell line and 7 and 8 against LNCaP cell line, with IC50 values ranging from 49.96 ± 1.74 to 76.92 ± 5.85 µM.
Microbial cells have extensively been utilized to produce value-added bioactive compounds. Based on advancement in protein engineering, DNA recombinant technology, genome engineering, and metabolic ...remodeling, the microbes can be re-engineered to produce industrially and medicinally important platform chemicals. The emergence of co-culture system which reduces the metabolic burden and allows parallel optimization of the engineered pathway in a modular fashion restricting the formation of undesired byproducts has become an alternative way to synthesize and produce bioactive compounds. In this study, we present genetically engineered
E. coli
-based co-culture system to the de novo synthesis of apigetrin (APG), an apigenin-7-
O
-β-
d
-glucopyranoside of apigenin. The culture system consists of an upstream module including 4-coumarate: CoA ligase (4CL), chalcone synthase, chalcone flavanone isomerase (CHS, CHI), and flavone synthase I (FNSI) to synthesize apigenin (API) from
p
-coumaric acid (PCA). Whereas, the downstream system contains a metabolizing module to enhance the production of UDP-glucose and expression of glycosyltransferase (PaGT3) to convert API into APG. To accomplish this improvement in titer, the initial inoculum ratio of strains for making the co-culture system, temperature, and media component was optimized. Following large-scale production, a yield of 38.5 µM (16.6 mg/L) of APG was achieved. In overall, this study provided an efficient tool to synthesize bioactive compounds in microbial cells.
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•A stress amplification structure employing free-standing SiC sensing elements was utilised to enhance 3C-SiC/Si pressure sensor sensitivity to 0.276 mV/V/kPa.•Analytical and ...numerical methods show that the stress in the structure is amplified by more than 750% compared to a traditional structure.•The fabricated sensor had a non-linearity of 2.2% and was highly repeatable with a low hysteresis of 0.91%.•The dual 3C-SiC thin film on the sensor provides a strong chemical protective capability due to its chemical inertness.
SiC based pressure sensors show tremendous promise for harsh environment applications thanks to their excellent mechanical, electrical, thermal, and chemical properties. This paper presents the design, fabrication, and characterisation of a highly sensitive and robust 3C-SiC/Si pressure sensor. The sensor utilises a stress amplification structure consisting of four Si pillars built up from the 3C-SiC/Si membrane, supporting a series of released n-type 3C-SiC sensing elements. When pressure is applied to the diaphragm, the pillars act to locally concentrate and amplify strain in the 3C-SiC sensing elements, resulting in over 7 times higher stresses/strains in these sensing elements compared to a traditional structure. Additionally, the front side of the sensor is fully covered by a 3C-SiC thin film, which provides a strong chemical protective capability, allowing the sensor to operate in harsh chemically corrosive environments. The robust device utilises the full Wheatstone bridge to negate the effects of temperature. Experimental results show that the fabricated sensor is highly stable, repeatable, has a high sensitivity of 0.276 mV/V/kPa and a maximum non-linearity of 2.2 % in the 0–100 kPa region. The results indicate that this smart-structure pressure sensor is promising for applications that require highly precise pressure sensing in aggressively corrosive environments.
Excessive antimicrobial usage and deficiencies in hygiene in meat production systems may result in undesirable human health hazards, such as the presence of antimicrobial drug residues and ...non-typhoidal Salmonella (NTS), including antimicrobial resistant (AMR) NTS. Recently, Vietnam has witnessed the emergence of integrated intensive animal production systems, coexisting with more traditional, locally-sourced wet markets. To date no systematic studies have been carried out to compare health hazards in beef, pork and chicken in different production systems. We aimed to: (1) estimate the prevalence of antimicrobial residues in beef, pork and chicken meat; (2) investigate the prevalence and levels of NTS contamination; and (3) investigate serovar distribution and AMR against critically important antimicrobials by animal species and type of retail (wet market vs. supermarket) in Vietnam. Fresh pork, beef and chicken meat samples (N=357) sourced from wet markets and supermarkets in Ho Chi Minh City (HCMC), Hanoi and Dong Thap were screened for antimicrobial residues by PremiTest, and were further investigated by Charm II. Samples from HCMC (N=113) were cultured using ISO 6579:2002/Amd 1:2007. NTS bacteria were quantified using a minimum probable number (MPN) technique. NTS isolates were assigned to serovar by Multilocus Sequence Typing (MLST), and were investigated for their phenotypic susceptibility against 32 antimicrobials. A total of 26 (7.3%) samples tested positive by PremiTest (9.5% beef, 4.1% pork and 8.4% chicken meat). Sulfonamides, tetracyclines and macrolides were detected by Charm in 3.1%, 2.8% and 2.0% samples, respectively. Overall, meat samples from wet markets had a higher prevalence of residues than those from supermarkets (9.6% vs. 2.6%) (p=0.016). NTS were isolated from 68.4% samples from HCMC. Chicken samples from wet markets had by far the highest NTS counts (median 3.2 logMPN/g). NTS isolates displayed high levels of resistance against quinolones (52.2%) and β-lactams (49.6%), but low levels against 3rd generation cephalosporins (4.4%) and aminoglycosides (0.8%). The highest adjusted prevalence of multidrug resistance (MDR) corresponded to isolates from chicken meat and pork (OR 8.3 and 1.8, respectively) (baseline=beef). S. Kentucky was the most common serovar identified (11 from chicken, 1 from beef) and 91.7% isolates was MDR. 11/12 isolates corresponded to ST198, a worldwide-disseminated multi-resistant NTS clone. We recommend stepping up policy measures to promote responsible antimicrobial use in animal production, as well as awareness about withdrawal periods to limit the hazard of residues in animal products, and improving slaughtering/hygiene procedures to limit cross-contamination with NTS, particularly in poultry wet markets.
•Antimicrobial residues were found in 7.3% meat samples (9.6% in meat from wet markets and 2.6% in meat from supermarkets).•Over two thirds (68.4%) of meat samples were contaminated with non-typhoidal Salmonella; 52.2% of isolates were multidrug resistant.•Chicken meat from wet markets had the highest loads of contamination with non-typhoidal Salmonella (median 3.2logMPN/g in positive samples).•Multidrug resistance was highest in Salmonella from chicken meat, and lowest in beef; the type of retail was not linked to increased resistance.•The most commonly identified serovar was multidrug resistant Salmonella Kentucky ST198, with high levels resistance against β-lactams and quinolones.
This work describes a simple single-step method for green synthesis of colloidal gold nanoparticles (AuNPs) using Litsea cubeba (LC) fruit extract as a reducing as well as stabilizing agent ...simultaneously. Major parameters affecting the formation of LC-AuNPs, including gold ion concentration, reaction time, and reaction temperature were optimized using ultraviolet-visible (UV-Vis) measurements at a characteristic maximum absorbance of 535 nm. The functional groups responsible for reducing gold ions and capping AuNPs were examined by Fourier-transform infrared (FTIR) spectroscopy. Powder X-ray diffraction (XRD) analysis revealed the crystalline nature of AuNPs. Transmission electron microscopy (TEM) measurements showed that the biosynthesized LC-AuNPs were mostly spherical with an average size of 8-18 nm. The nanoparticles also demonstrated excellent ultrarapid catalytic activity for the complete reduction of 4-nitrophenol to p-aminophenol in the presence of NaBH4 within 10 min with a reaction rate constant of 0.348 min-1.
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