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In this paper, a compact antenna with flexible and controllable bandwidth characteristics is proposed. To ensure wide coverage along with an omnidirectional radiation pattern, a monopole structure was utilized as the primary radiating element of the proposed antenna. The monopole was fed using a coplanar waveguide technique to achieve a single-layer design. To alter the operating bandwidth, defined by a reflection coefficient of less than −10 dB, a single stub was directly connected to the feeding transmission line. By controlling the stub's length, matching performance in the high-frequency range was found to undergo significant degradation, indicating that the operating bandwidth could be controlled. Furthermore, for validation, two antenna prototypes were fabricated and measured under different circumstances. In the unbending mode, the design without the stub achieved a wideband of 51.6%, while the other design with the stub exhibited a narrower band of about 19.6%. Additionally, the antennas worked efficiently when operating in bending mode. It is also worth noting that the antenna gain and radiation pattern remained stable across the entire operating bandwidth.

This paper introduces the design of a circularly polarized metasurface-based antenna array for C-band satellite applications that owns broadband operation and high gain characteristics. The single radiating element comprises a Y-shape patch and an above-placed 2 × 2 unit-cell metasurface. Further improvement in operating bandwidth and broadside gain is achieved by arranging four single elements in a 2 × 2 configuration and a sequential-phase feed network. A prototype has been fabricated and measured to validate the feasibility of the proposed antenna array. The measured operating bandwidth is 20% (4.50–5.50 GHz), which is an overlap between a −10 dB impedance bandwidth of 29.8% (4.50–5.99 GHz) and a 3 dB axial ratio bandwidth of 20% (4.50–5.50 GHz). Across this operating band, the peak broadside gain is 10.5 dBi. Compared with the recently published studies, the proposed array is a prominent design for producing a wide operating bandwidth and relatively high gains while maintaining the overall compact dimensions.

This paper proposes a compact design of dual-sense circularly polarized (CP) antenna for simultaneous transmit (Tx) and receive (Rx) communication systems. The primary radiating aperture of the proposed antenna is a 2 × 2 unit-cell metasurface (MS). The MS is excited by the asymmetric patch in the center, which acts as the CP source of the whole antenna structure. By properly tuning the feeding positions, dual-sense CP with high isolation can be achieved. For verification, an antenna prototype with compact dimensions of 0.36λ × 0.36λ × 0.02λ (λ is the free-space wavelength at the center operating frequency) is fabricated and measured. The measured operating bandwidth is 1.6% (2.45-2.49 GHz), in which the reflection and transmission coefficients are less than-10 dB and the axial ratio is lower than 3 dB. Within this band, the maximum isolation value is 39 dB, and the peak gain is 5.7 dBi.

Seven new oleanane- type triterpene saponins, lysimaponins A-G, were isolated from aerial parts of Lysimachia laxa Baudo. Their chemical structures have been elucidated by analysis of spectroscopic and chemical methods. All compounds were evaluated for their antibacterial effects against Microcystis aeruginosa, Vibrio parahaemolyticus, V. harveyi, V. vulinificus, V. cholerae , and V. alginolyticus. All compounds showed potent antibacterial activities against the cyanobacteria M. aeruginosa with IC50 values ranging from 14.4 ± 1.2 to 35.3 ± 2.2 µg/mL. Compounds 1, 2, 4 - 7 inhibited V. parahaemolyticus with MIC values ranging from 64 to 256 µg/mL. The results suggested that saponins from L. laxa could be potential anti-cyanobacteria agents. [ABSTRACT FROM AUTHOR]

Fingerprinting techniques, which utilize the unique chemical and physical properties of food samples, have emerged as a promising approach for food authentication and traceability. Recent studies have demonstrated significant advancements in food authentication through the use of fingerprinting methods, such as multivariate statistical analysis techniques applied to trace elements and isotope ratios. However, further research is required to optimize these methods and ensure their validity and reliability in real-world applications. In this study, the inductively coupled plasma mass spectrometry (ICP-MS) analytical method was employed to determine the content of 21 elements in 300 cashew nut (Anacardium occidentale L.) samples from 5 brands. Multivariate statistical methods, such as principal components analysis (PCA), were employed to analyze the data obtained and establish the provenance of the cashew nuts. While cashew nuts are widely marketed in many countries, no universal method has been utilized to differentiate the origin of these nuts. Our study represents the initial step in identifying the geographical origin of commercial cashew nuts marketed in Vietnam. The analysis showed significant differences in the means of 21 of the 40 analyzed elements among the cashew nut samples from the 5 brands, including 7Li, 11B, 24Mg, 27Al, 44Ca, 48Ti, 51V, 52Cr, 55Mn, 57Fe, 60Ni, 63Cu, 66Zn, 93Nb, 98Mo, 111Cd, 115In, 121Sb, 138Ba, 208Pb, and 209Bi. The PCA analysis indicated that the cashew nut samples can be accurately classified according to their original locations. This research serves as a prerequisite for future studies involving the combination of elemental composition analysis with statistical classification methods for the accurate establishment of cashew nut provenance, which involves the identification of key markers for the original discrimination of cashew nuts.

Summary: The objective of this study was to employ multi‐elemental analysis and chemometric multivariate data analysis for identifying the geographical origin of Camellia sinensis cultivated in Vietnam's northeastern region. Ninety‐two tea leaf samples encompassing four distinct varieties were sourced from Bac Can and Thai Nguyen provinces. These samples underwent analysis through Fourier transform infrared (FTIR) spectroscopy and chemometrics, while elemental quantification was achieved via inductively coupled plasma mass spectrometry (ICP‐MS), utilising mixed standards for 26 elements. The FTIR spectra exhibited characteristic peaks, denoting the functional groups of the potential compounds present. ICP/MS analysis identified the presence of 14 elements in the tea samples, revealing significant variations in content across the four varieties. principal component analysis (PCA) of the FTIR data illustrated that the initial two principal components accounted for 91.26% of the total variance, effectively segregating the four green tea varieties into distinct clusters. Conversely, PCA of the ICP‐MS spectra also distinguished the four varieties, albeit Trung Du and Hybrid F1 exhibited a proximate distribution. This closeness may be incidental and not indicative of correlation, considering the limited variable set. Our findings ascertain that ICP/MS and FTIR, augmented by chemometric software, serve as efficacious tools for ascertaining the geographical origins of tea. [ABSTRACT FROM AUTHOR]

Summary: The purpose of this protocol is to screen and identify the physiologically relevant interactors of a lysosomal protein in living cells. Here, we describe how to identify solute carrier family 15 member 4 (SLC15A4)-interacting proteins by BioID and mass spectrometry analysis. This protocol utilizes fusion of SLC15A4 with a mutant form of biotin ligase, BirA. The fusion protein can promiscuously biotinylate the proteins proximal to SLC15A4. The biotinylated endogenous proteins are pulled down by magnetic streptavidin beads and detected by mass spectrometry analysis.For complete details on the use and execution of this protocol, please refer to Kobayashi et al. (2021).

Cordyceps militaris, well known for its therapeutic potential in managing type-2 diabetes through the inhibition of α-amylase and α-glucosidase enzymes, was the central focus of this research, which investigated the influence of various cultivation substrates on its enzymatic inhibitory properties and bioactive compound content. Previous studies have primarily focused on the general pharmacological benefits of C. militaris but have not thoroughly explored how different substrates affect its bioactive profile and enzyme inhibitory activities. This study aimed to evaluate the impact of substrate selection on the enzyme inhibition activities and the levels of bioactive compounds such as cordycepin and adenosine in C. militaris, demonstrating that substrate selection markedly affects both these enzymes' inhibition activities and bioactive compound levels. Particularly, C. militaris fruiting bodies grown on Brihaspa atrostigmella showed the highest concentrations of cordycepin (2.932 mg/g) and adenosine (1.062 mg/g). This substrate also exhibited the most potent α-glucosidase inhibition with an IC50 value of 336.4 ± 16.0 µg/mL and the most effective α-amylase inhibition with an IC50 value of 504.6 ± 4.2 µg/mL. Conversely, C. militaris cultivated on the solid residues of Gryllus bimaculatus displayed the strongest xanthine oxidase (XOD) inhibition, with the lowest IC50 value of 415.7 ± 11.2 µg/mL. These findings highlight the critical role of substrate choice in enhancing the medicinal properties of C. militaris, suggesting that optimized cultivation can enhance the bioactive properties for more effective natural therapies for diabetes and other metabolic disorders. This study not only extends the understanding of C. militaris' pharmacological potential but also illustrates its applicability in developing customized treatment options. [ABSTRACT FROM AUTHOR]

Gnetum formosum Markgr., a member of the Gnetaceae family, is distributed in Vietnam. This plant remains a botanical enigma with an unexplored diversity of chemical constituents and pharmacological effects. In this study, two new steroidal saponins, namely gnetumosides A (1) and B (2), were isolated from the aerial parts of G. formosum. Their chemical structures were elucidated using spectroscopic techniques, including high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) and NMR, along with chemical hydrolysis and comparison with the reported literature. The potential anti-inflammatory effects of the isolated compounds were evaluated by measuring lipopolysaccharide-stimulated nitric oxide (NO) production in murine macrophage cells. Notably, compound 1 exhibited the most potent inhibitory activity (IC50 = 14.10 ± 0.75 µM), comparable to dexamethasone. Additionally, the mechanisms underlying the observed anti-inflammatory effects were investigated through molecular docking and molecular dynamics simulations on inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) proteins. This study is the first to investigate the chemical constituents and pharmacological effects of G. formosum. [ABSTRACT FROM AUTHOR]

Lutraria rhynchaena Jonas, 1844 is of great commercial interest, but its reserves have dramatically declined over recent decades. Therefore, there is an urgent need of scientific basis to propose effective fishery management measures and improve artificial aquaculture of the clam. In this study, we investigated the distribution and density of L. rhynchaena, sediment characteristics, and established the clam’s reproductive cycle through monthly observations from August 2017 to July 2018. The study results showed that distribution and density of clams are related to sediment types, and the sediment type of medium sand is likely the best benthic substrate for the clams. The spawning of clams occurred throughout the year with three spawning peaks in January, April and September. For the sustainable management of the clam resource in Cat Ba-Ha Long Bay, the fishery authorities can issue a ban on harvest of the clam in spawning peak months in January, April and September.

Rapid urbanization has led to increased environmental pollution in Vietnam, especially air pollution issues. In this study, we used gas chromatography-mass spectrometry with an automated identification and quantification system database to detect and quantitate compounds in atmospheric fine particulate matter (PM2.5). A total of 288 compounds classified in 19 pollutant categories based on their origins were detected in PM2.5 samples collected in three areas of Hanoi during winter. The total content of substances detected ranged from 41.08 to 795.00 ng.m−3. The characteristics and concentrations of organic pollutants differed among the industrial, urban, and agricultural sampling areas, with average concentrations of 179.00, 112.10, and 529.40 ng.m−3, respectively. In this comprehensive study on trace organic compounds conducted with samples collected at three sites, we investigating the basic impact of three main factors on the environment. This study contributes to the literature by providing a data set on the content of trace organic substances in the air at the study site.

Alkaloids are among the most important and best-known secondary metabolites as sources of new drugs from medicinal plants and marine organisms. A phytochemical investigation of the whole plant of Crinum asiaticum var. sinicum resulted in the isolation of seven alkaloids (1–7), including one new dimeric compound, bis-(-)-8-demethylmaritidine (1). Their structures were elucidated using NMR and HR-ESI-MS. The absolute configuration of new compound 1 was established by circular dichroism spectroscopy. All isolated compounds were evaluated for their inhibitory effects on acetylcholinesterase (AChE) activity in vitro. Among them, compound 1 exhibited the most potent AChE inhibition. Moreover, molecular docking and molecular dynamics simulations were carried out for the most active compound to investigate their binding interactions and dynamics behavior of the AChE protein-ligand complex. Therefore, compound 1 may be a potential candidate for effectively treating Alzheimer's disease. [ABSTRACT FROM AUTHOR]

One new indol, N-methoxymethyltryptophol (1), one new phenolic, (2 R)-2-(4-hydroxyphenyl)ethyl 2-hydroxy-3-phenylpropanoate (2) and fifteen known compounds (3–17) were isolated from the methanol extract of the fermentation of marine microalgae Aurantiochytrium sp. SC145. Their structures were elucidated by 1D-, 2D-NMR spectroscopic analysis, HR-ESI-MS, quantum chemical calculation methods and by comparing their NMR data with those reported in the literature. All compounds were evaluated for their antimicrobial activities against microorganisms. Compounds 2, 3 and 11 significantly exhibited antimicrobial activities on all tested Gram-(+), Gram-(-) bacteria and the yeast C. albicans with MIC values ranging from 32 to 256 µg/mL. [ABSTRACT FROM AUTHOR]