In this study, the development of our purpose‐made capacitively coupled contactless conductivity detection (C4D) for CE is reported. These systems have been employed as a simple, versatile, and ...cost‐effective analytical tool. CE‐C4D devices, whose principle is based on the control of the ion movements under an electrical field, can be constructed even with a modest financial budget and limited infrastructure. A featured application was developed for quality control of antimicrobial drugs using CE‐C4D, with most recent work on determination of aminoglycoside and glycopeptide antibiotics being communicated. For aminoglycosides, the development of CE‐C4D methods was adapted to two categories. The first one includes drugs (liquid or powder form) for intravenous injection, containing either amikacin, streptomycin, kanamycin A, or kanamycin B. The second one covers drugs for eye drops (liquid or ointment form), containing either neomycin, tobramycin, or polymyxin. The CE‐C4D method development was also made for determination of some popular glycopeptide antibiotics in Vietnam, including vancomycin and teicoplanin. The best detection limit achieved using the developed CE‐C4D methods was 0.5 mg/L. Good agreement between results from CE‐C4D and the confirmation method (HPLC‐ Photometric Diode Array ) was achieved, with their result deviations less than 8% and 13% for aminoglycoside and glycopeptide antibiotics, respectively.
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•Enzymatic hydrolysis was used to gain iron-binding Acetes japonicus proteolysate.•Proteolysate having functional features could be used to enhance food properties.•The proteolysate ...encompassed approximately 38.77 % of indispensible amino acids.•The 1−3 kDa peptide fraction exerted the highest metal-chelating activity.•Two iron-binding peptides, DSVNFPVHGL and FKVGQENTPILK, were identified.
Recovery of functional iron-binding protein hydrolysate from Acetes japonicus employing enzymatic hydrolysis and iron-chelating peptide identification were conducted in this study. The result showed that under the optimal hydrolysis condition including Flavourzyme, pH 5, 50 °C, E:S ratio of 27.4 U/g protein and hydrolysis time of 4.8 h, the obtained proteolysate displayed the maximal iron-binding capacity (IBC) of 177.7 μgFe2+/g protein and comprehended 38,77 % of essential amino acids. Functional features of the Acetes proteolysate encompassing solubility, heat stability, foaming and emulsifying property, oil and water holding capacity were also noteworthy. Peptide fractionation was performed using ultrafiltration and the 1−3 kDa fraction expressed the highest IBC of 120.43 ± 0.15 μgFe2+/g protein, 13.7 times lower than that of disodium ethylenediaminetetraacetate (Na2EDTA). From this fraction, two iron-binding peptides of DSVNFPVHGL (1083.53 Da) and FKVGQENTPILK (1372.77 Da) were identified utilizing nano-UHPLC-MS/MS as well as their de novo spatial structures and interaction with ferrous ion were simulated by PEP-FOLD 3. As a whole, the proteolysate/peptides could be filled as an iron chelator which could shield human body from iron deficient-related disorders or as a functional proteolysate preparation to upgrade food properties.
Comprehensive profiling of actionable mutations in non-small cell lung cancer (NSCLC) is vital to guide targeted therapy, thereby improving the survival rate of patients. Despite the high incidence ...and mortality rate of NSCLC in Vietnam, the actionable mutation profiles of Vietnamese patients have not been thoroughly examined. Here, we employed massively parallel sequencing to identify alterations in major driver genes (EGFR, KRAS, NRAS, BRAF, ALK and ROS1) in 350 Vietnamese NSCLC patients. We showed that the Vietnamese NSCLC patients exhibited mutations most frequently in EGFR (35.4%) and KRAS (22.6%), followed by ALK (6.6%), ROS1 (3.1%), BRAF (2.3%) and NRAS (0.6%). Interestingly, the cohort of Vietnamese patients with advanced adenocarcinoma had higher prevalence of EGFR mutations than the Caucasian MSK-IMPACT cohort. Compared to the East Asian cohort, it had lower EGFR but higher KRAS mutation prevalence. We found that KRAS mutations were more commonly detected in male patients while EGFR mutations was more frequently found in female. Moreover, younger patients (<61 years) had higher genetic rearrangements in ALK or ROS1. In conclusions, our study revealed mutation profiles of 6 driver genes in the largest cohort of NSCLC patients in Vietnam to date, highlighting significant differences in mutation prevalence to other cohorts.
Active magnetic bearing (AMB) systems support rotating shafts without any physical contact, using electromagnetic forces. Each radial AMB uses two pairs of electromagnets at opposite sides of the ...rotor. This allows the rotor to float in the air gap, and the machine to operate without frictional losses. In active magnetic suspension, displacement sensors are necessary to detect the radial and axial movement of the suspended object. In a high-speed rotating machine equipped with an AMB, the rotor bending modes may be limited to the operating range. The natural frequencies of the rotor can cause instability. Thus, notch filters are a useful circuit for stabilizing the system. In addition, commercial displacement sensors are sometimes not suitable for AMB design, and cannot filter the noise caused by the natural frequencies of rotor. Hence, implementing displacement sensors based on the AMB structure is necessary to eliminate noises caused by natural frequency disturbances. The displacement sensor must be highly sensitive in the desired working range, and also exhibit a low interference noise, high stability, and low cost. In this study, we used the differential inductive sensor head and lock-in amplifier for synchronous demodulation. In addition, an active low-pass filter and a notch filter were used to eliminate disturbances, which caused by natural frequencies. As a consequence, the inductive displacement sensor achieved satisfactory linearity, high sensitivity, and disturbance elimination. This sensor can be easily produced for AMB applications. A prototype of these displacement sensors was built and tested.
This study aimed to evaluate the unique phenotype of the Vietnamese polycystic ovarian syndrome (PCOS) population.
In this multicenter cross-sectional descriptive study, a total of 901 ...reproductive-age women were recruited at three medical centers in Vietnam from June 2016 to May 2018. Group I included 479 patients with PCOS (Rotterdam 2003 consensus) and Group II included 422 non-PCOS women, consisted of women with regular menstrual cycle, collected at the same time of PCOS recruitment, without ovarian disease or ovarian failure. Main outcome measures were anthropomorphic, serum hormone, ultrasound and physical characteristics of PCOS.
The Vietnamese PCOS population was lean, but with a higher weight and body mass index compared to controls. About 34.4% of PCOS subjects had hirsutism, primarily confined to the leg, arm and pubis. The PCOS population had higher serum luteinizing hormone (LH), LH : follicle stimulating hormone ratio, anti-Mullerian hormone and testosterone. The PCOS population had double the ovarian volume compared to controls. PCOS subjects had no increase in metabolic disease history and had on average optimal serum markers for low metabolic disease risk. Group D (O + polycystic ovary morphology PCOM) was the most prevalent phenotype noted in our Vietnamese PCOS cohort (67.6%). Modified Ferriman-Gallwey, levels of LH, testosterone and anti-Mullerian hormone were highest in Group A (O + H + PCOM) and lowest in Group D (O + PCOM).
The Vietnamese PCOS population is characterized by a lean body type, nonfacial hirsutism, anovulatory, enlarged ovaries and typical PCOS serum hormone markers, low risk factors for metabolic syndrome. Nonclassical phenotypes for PCOS were more frequent than the classic phenotype.
•Vitamin B6 and Mg were simultaneously determined by CE-C4D.•Vitamin B6 and Mg peaks were well separated within < 10 min.•A simple and reliable method was developed for pharmaceutical/nutraceutical ...samples.•Single-run CE-C4D analysis can replace HPLC and ICP-OES conventional methods.•Acceptable agreement between measured/label claim contents was achieved.
Vitamins and minerals are usually incorporated in pharmaceutical and nutraceutical products, but a simple, rapid, and inexpensive analytical method for their simultaneous determination is still lacking. In this study, we developed a quantification method for pyridoxine (vitamin B6) and magnesium (Mg) by using purpose-made capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C4D) instrument. Main analytical conditions include: fused silica capillary (total length 55 cm, effective length 40 cm, inner diameter 50 μm); background electrolyte consisted of 10 mM L-arginine/acetic acid (pH 5) with 20% acetonitrile; separation voltage + 20 kV; hydrodynamic injection (siphoning at 20 cm in 25 s). Detection limits of vitamin B6 and Mg were 1 and 0.1 mg/L, respectively. Good linearity (R2 > 0.999) was observed for vitamin B6 and Mg calibration curves over concentration ranges of 3–100 and 0.3–200 mg/L, respectively. The method was applied to analyze vitamin B6 and Mg in several pharmaceutical and nutraceutical samples. The analytical results obtained by our method were in good agreement with reference methods (i.e., HPLC for vitamin B6 and ICP-OES for Mg). High-efficient and low-cost CE-C4D method can accordingly serve as a promising tool for concurrent analysis of inorganic and organic species in pharmaceutical and nutraceutical analysis.
Na4Mn9O18 was recognized as the most interesting material for sodium ion batteries due to its low cost, high specific capacity and good cycle performance. The excellent electrochemical performance of ...Na4Mn9O18 nanostructures was shown in literature. In this work, Na4Mn9O18 nanowires were synthesized by hydrothermal reactions of Mn2O3 powder and NaOH solution at the temperatures of 185–205 °C for 48–96 h. The investigation of composition and structure of the synthesized products via scanning electron microscopy and X-ray diffraction analyses showed that major intermediate products at the low and high temperatures were Mn3O4 and birnessite Na0.55Mn2O41.5H2O, respectively. The synthesized Na4Mn9O18 nanowires showed a good electrochemical performance with discharge capacities of over 90 mAhg−1, and Coulombic efficiencies of more than 91% at a rate of 0.2C during 30 cycles of charge/discharge.
A dietary exposure and health risk assessment of mycotoxins including aflatoxin B1, fumonisin B1, ochratoxin A, and zearalenone was conducted in 3 provinces in Northern Vietnam namely Hanoi, Thanh ...Hoa, and Ha Giang. Results of the analysis of samples of maize, rice, peanut, and sesame revealed the presence of these mycotoxins in all samples and sampling locations. Aflatoxin B1 was the most frequently detected (19.1%) and widely distributed among different types of samples, whereas the percentage occurrence of fumonisin B1, ochratoxin A, and zearalenone were 11.2, 5.9 and 6.3, respectively. The later three mycotoxins were detected mostly in maize. The exposure to aflatoxin B1 at detected levels could lead to 0.23, 0.65 and 21.0 cases of liver cancer per 100,000 adult people per year in Hanoi, Thanh Hoa and Ha Giang, respectively. The risk assessment also showed the unsafe exposure to ochratoxin A and fumonisin B1 in the highland region where the people consume a large amount of foods derived from maize. In Ha Giang, the mean exposures to fumonisin B1 were lower than its PMTDI (Provisional Maximum Tolerable Daily Intake), however, the 95th percentile values were 1.1–1.9 times of the PMTDI. The mean exposures to ochratoxin A in Ha Giang were about 2.4–3.6 times higher than its PMTWI (Provisional Maximum Tolerable Weekly Intake). There was no risk of fumonisin B1 and ochratoxin A in Hanoi and Thanh Hoa. The dietary exposure to zearalenone was within its PMTDI in all locations. The results pointed out the need for further improvement of the control of these mycotoxins in Vietnam, especially in some highland provinces.
•Higher mycotoxins content in food in Ha Giang compared to other localities.•High exposure doses of mycotoxins in highland due to long storage time of maize.•Different liver cancer risk caused by aflatoxin B1 exposure in three provinces.•Unsafe exposure to ochratoxin A and fumonisin B1 in the highland region.•No risk caused by zearalenone exposure in the studied provinces.
The occurrence of okadaic acid (OA) group toxins in bivalve mollusk collected from Vietnamese coastal areas was investigated from April 2016 to April 2017. OA group toxins were detected in mollusk by ...UPLC-MS/MS with the highest level of 11.3 ng/g and detection frequency of 11.8%. Toxins were detected more frequently in dry season (14.4% of analyzed samples) than in wet season (7.9%). Toxins were also detected more frequently at sampling locations in the northern parts (≥10.4%) than in the southern part (≤8.3%) of Vietnamese coastline. Results of this study were similar to those obtained in long-term studies in regions geographically close to Vietnam, confirming decisive influence of geographic location on the accumulation of toxins in mollusks.
Within the scope of the study, toxin levels in all contaminated samples were below the regulation limit (160 ng/g), but the presence of OA group toxins in bivalve mollusk suggests the need of a more stringent control of toxins in bivalve mollusk in Vietnam.
•Okadaic acid and DTXs can be detected round the year in mollusks in Vietnamese seacoast.•In Viet Nam, the risk of accumulating okadaic acid and DTXs in mollusk is higher in dry season.•Okadaic acid is the most commonly detected DSP toxin in mollusks in Vietnam.
•New design of CE-C4D purpose-made system.•CE-C4D methods for analyses of β-lactam-based antibiotics.•Affordable tool for quality control and detection of counterfeiting of antibiotic formulations.
A ...simple and inexpensive approach for determination of various antimicrobial drugs using a purpose-made compact capillary electrophoresis (CE) instrument with capacitively coupled contactless conductivity detection (C4D) is reported. The objective of the work is to propose an affordable and easily-implemented tool for quality control and detection of counterfeiting of antibiotic formulations in resource constrained developing countries. The design of the purpose-made CE-C4D system was improved according to the feedback from over 10 years of use of our previous instrument. CE-C4D methods were for the first time developed to analyze β-lactam-based antibiotics commonly used in Vietnam, including single- β-lactam antibiotics (i.e. Cephalexin, Cefotaxime Sodium, Cefixime and Sulbactam) as well as β-lactams co-formulated with Sulbactam (i.e. Amoxicillin, Ampicillin, Cefoperazone and Sulbactam). Single β-lactam antibiotics were analyzed using a background electrolyte (BGE) composed of Tris/Ace (10 mM, pH 7.8) whereas β-lactam – Sulbactam combinations were simultaneously separated using a BGE containing Tris/Ace (10 mM, pH 7.5). The best achieved detection limits were 2.0 mg/L and 1.0 mg/L for these two groups, respectively. Good agreement between results obtained from CE-C4D and standard confirmation methods (LCMS) was achieved, with a coefficient of determination, r2, of 0.9991. The applicability of the developed CE-C4D method was demonstrated for quality control of 24 β-lactam-based antimicrobial drugs available in Vietnam.
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