PURIFICATION OF PHOSPHOGYPSUM FOR USE AS CEMENT RETARDER BY SULPHURIC ACID TREATMENT

Phosphogypsum is a by-product of the wet phosphoric acid production. In this study, chemical compositions of phosphogypsum waste (PG) in Hai Phong diammonium phosphate plant (DAP1) and Lao Cai diammonium phosphate plant (DAP2) in Vietnam were surveyed for the purpose of gypsum recovery by P2O5, F removal to meet TCVN11833 for use treated gypsum as cement retarder. Studies of impurities P2O5, F, TOC removal by sulfuric acid 10 % at 28 0C was presented. The results found that the combination of a low concentration of sulfuric acid treatment, washing, lime neutralizing, and thermal treatment was successful in Phoshogypsum treatment for use as cement retarder. The cement test proved that treated PG could partially replace natural gypsum as a retarder.Keywords:  phosphogypsum treatment, phosphorus pentoxide removal, calcium sulfate transition phase, cement retarder.

Research antioxidant activity of chitooligosacchride by UV-VIS absorption spectrocopy

Chitosan with 80% degree of deacetylation was hydrolyzed by cellulase of Trichoderma viride to prepare chitooligosaccharides (COSs) by the fractionation of the COSs with ultrafiltration membrane. The antioxidant activities of the COSs were clarified in this study by reducing power and free radical scavenging ability assay by UV-VIS absorption spectrum. The results show that the COS 1 (10,000-5,000 Da), COS 2 (5,000-3,000 Da), COS 3 (3,000-1,000 Da) and COS 4 (less than1,000 Da) segments have antioxidant properties.The antioxidant activitives of the COSs increased with the increment of concentration, and they also depended on molecular weight

The acceptance of mobile applications for accommodation booking in Vietnam: Case of gen Z

The development of technology and smart mobile devices such as phones and tablets has changed the behavior of tourists when booking tourism services. Based on the technology acceptance model, this study aims to explore the factors influencing the intention to use mobile applications for accommodation booking among GENZ in Vietnam. The analysis of 218 users revealed that four factors influence the behavior of using mobile applications for booking: performance expectancy, effort expectancy, social influence, and hedonic motivation. In addition to identifying the factors affecting usage intention, this study also proposes implications to assist developers and providers in improving their applications and developing suitable product strategies for the future

SYNTHESIS AND CYTOTOXICITY OF POLYHYDROXYLATED CHOLESTEROL DERIVATIVES

Eight polyhydroxylated cholesterol derivatives (1-8) were prepared from cholesterol, using oxidative reagents as SeO2, OsO4/NMO, HCOOH/H2O2 and BH3/ H2O2. Their structures were elucidated by using physical methods including NMR 1D and 2D. These compounds were evaluated against two cancer cell lines (Hep-G2, T98). Compounds 2, 4 and 8 inhibits human hepatocellular carcinoma cell line (Hep-G2) with IC50 4.69, 4.98 and 2.89 µg/mL, respectively. In addition, compound 8 exhibited strong cytotoxicity against T98 cell line (glioblastoma) with IC50 = 2.28 μM

Safety and efficacy of fluoxetine on functional outcome after acute stroke (AFFINITY): a randomised, double-blind, placebo-controlled trial

Background Trials of fluoxetine for recovery after stroke report conflicting results. The Assessment oF FluoxetINe In sTroke recoverY (AFFINITY) trial aimed to show if daily oral fluoxetine for 6 months after stroke improves functional outcome in an ethnically diverse population. Methods AFFINITY was a randomised, parallel-group, double-blind, placebo-controlled trial done in 43 hospital stroke units in Australia (n=29), New Zealand (four), and Vietnam (ten). Eligible patients were adults (aged ≥18 years) with a clinical diagnosis of acute stroke in the previous 2–15 days, brain imaging consistent with ischaemic or haemorrhagic stroke, and a persisting neurological deficit that produced a modified Rankin Scale (mRS) score of 1 or more. Patients were randomly assigned 1:1 via a web-based system using a minimisation algorithm to once daily, oral fluoxetine 20 mg capsules or matching placebo for 6 months. Patients, carers, investigators, and outcome assessors were masked to the treatment allocation. The primary outcome was functional status, measured by the mRS, at 6 months. The primary analysis was an ordinal logistic regression of the mRS at 6 months, adjusted for minimisation variables. Primary and safety analyses were done according to the patient's treatment allocation. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12611000774921. Findings Between Jan 11, 2013, and June 30, 2019, 1280 patients were recruited in Australia (n=532), New Zealand (n=42), and Vietnam (n=706), of whom 642 were randomly assigned to fluoxetine and 638 were randomly assigned to placebo. Mean duration of trial treatment was 167 days (SD 48·1). At 6 months, mRS data were available in 624 (97%) patients in the fluoxetine group and 632 (99%) in the placebo group. The distribution of mRS categories was similar in the fluoxetine and placebo groups (adjusted common odds ratio 0·94, 95% CI 0·76–1·15; p=0·53). Compared with patients in the placebo group, patients in the fluoxetine group had more falls (20 [3%] vs seven [1%]; p=0·018), bone fractures (19 [3%] vs six [1%]; p=0·014), and epileptic seizures (ten [2%] vs two [<1%]; p=0·038) at 6 months. Interpretation Oral fluoxetine 20 mg daily for 6 months after acute stroke did not improve functional outcome and increased the risk of falls, bone fractures, and epileptic seizures. These results do not support the use of fluoxetine to improve functional outcome after stroke

Totally endoscopic resection of giant left atrial myxoma without robotic assistance

There was no report on the application of totally endoscopic surgery for giant atrial myxoma resection. A 62-year-old female patient with giant atrial myxoma causing severe mitral stenosis and acute pulmonary edema underwent a successful operation by totally endoscopic techniques without the assistance of robotic systems using four small trocar ports (three 5-mm trocars and one 12-mm trocar). The patient recovered uneventfully and was satisfied with cosmetic results

The Suppressive Activity of Water Mimosa Extract on Human Gastric Cancer Cells

Epidemiological studies have evidenced that natural dietary products can prevent or manage gastric cancer. Neptunia oleracea, an aquatic vegetable and edible plant, has been reported to have anti-cancer properties. In this study, N. oleracea extract’s suppression of gastric cancer cells was investigated on an in vitro experimental model. We found that ethyl acetate (EtOAc) extract inhibited cell proliferation at IC50 value of 172 µg/mL. Moreover, the treatment of EtOAc extract at a concentration of 50 µg/mL for 24 h caused suppression of cancer cell migration. Notably, a real-time PCR assay revealed that EtOAc extract induced the process of apoptosis via upregulating the mRNA expression level of caspase-8, Bax, caspase-9, and caspase-3 in cancer cells. In conclusion, N. oleracea had potential anti-cancer activity against gastric cancer cells, suggesting its role in the prevention and management of gastric cancer

Totally endoscopic cardiac surgery for atrial septal defect repair on beating heart without robotic assistance in 25 patients

The aim of the study was to investigate the effectivity and safety of totally endoscopic cardiac surgery without robotic assistance for atrial septal defect (ASD) closure on beating hearts.Twenty-five patients (adults/children: 15/10) underwent ASD closure using nonrobotically assisted totally endoscopic approach on beating heart. Three 5-mm trocars and one 12-mm trocar were used, only the superior vena cava is snared, filling the pleural and pericardial cavities with CO2, and the heart was beating during the surgery. Twenty-three patients had isolated secundum ASD (2 of which had severe tricuspid regurgitation) and two patients had ASD combined with partial anomalous pulmonary venous connection. All ASDs were closed using artificial patch, continuous suture; tricuspid regurgitations were repaired and the anomalous pulmonary veins were drained to the left atrium.No postoperative complications or deaths occurred. Mean ± SD operation time and mean cardiopulmonary bypass time were 267.2 ± 44.6 and 156.1 ± 33.6 min, respectively. These patients were extubated within the first 5 hours, and the volume of blood drainage on the first day was less than 80 mL. Four days after surgery, patients did not need analgesics and were able to return to normal activities 1 week postoperatively.Totally endoscopic operation for ASD closure on beating heart is safe, with short recovery period, and surgical scars are of high cosmetic value, especially in a woman and girl

BƯỚC ĐẦU KHẢO SÁT ĐỘT BIẾN GEN BRCA1 VÀ BRCA2 T RONG QUẦN THỂ UNG THƯ BIỂU MÔ BUỒNG TRỨNG NGƯỜI VIỆT NAM BẰNG KỸ THUẬT GIẢI TRÌNH TỰ THẾ HỆ MỚI

BRCA1 and BRCA2 are two important tumor suppressor genes. The germline and somatic mutations of these two genes in ovarian carcinomas are sensitive for treatment with ADP-ribose polymerase enzyme inhibitor (PARPi). Recently, several PARPi drugs, such as Olaparib and Rucaparib, have been approved for ovarian cancer with BRCA1/2 germline mutations by Food and Drug Administration (FDA), and for both germline and somatic mutations by European Medicines Agency (EMA). However, there have no been reliable data about the prevalence of mutations of these two genes in ovarian carcinomas population for treatment in Vietnam so far. Therefore, we studied the prevalence of the BRCA1/2 germline and somatic mutations among ovarian carcinomas patients in the Vietnamese population. In this study, we sequenced these two genes by using Ion Torrent PGM. The subjects of the study are 11 formalin-fixed paraffin-embedded tumor (FFPE) samples from 11 patients with ovarian carcinomas obtained from Tu Du Hospital of Obstetrics and Gynecology (Vietnam). Multiplex PCR then was performed on the DNA samples and two controls containing known mutations by using Oncomine BRCA Research Assay. Of the sequenced 11 samples, a pathogenic mutation (1/11 patient, 9.1%) detected on the BRCA1 gene was a nonsense point mutation causing stop codon at the position of amino acid 1772. Consequently, our sequencing workflow shows the success in identifying and investigating the prevalence of BRCA1/2 mutation in a small group of ovarian carcinomas with FFPE tumor samples.BRCA1 và BRCA2 là hai gen ức chế khối u quan trọng. Việc đột biến hai gen này ở bệnh nhân ung thư biểu mô buồng trứng dòng mầm và dòng sinh dưỡng thì đáp ứng tốt hơn với thuốc ức chế enzyme poly(ADP-ribose) polymerase inhibitor (PARPi). Gần đây, một vài thuốc PARPi, như Olaparib và Rucaparib, đã được chấp thuận dùng cho bệnh nhân ung thư buồng trứng với đột biến dòng mầm BRCA1/2 bởi Food and Drug Administration (FDA) và với đột biến dòng mầm và dòng sinh dưỡng đối với European Medicines Agency (EMA). Tuy nhiên, hiện nay Việt Nam chưa có dữ liệu nào đáng tin cậy về tình trạng đột biến hai gen này trong quần thể bệnh nhân ung thư biểu mô buồng trứng nhằm hỗ trợ cho điều trị. Do đó, chúng tôi tiến hành giải trình tự nhằm khảo sát đột biến hai gen BRCA1/2 dòng mầm và dòng sinh dưỡng ở bệnh nhân ung thư biểu mô buồng trứng người Việt Nam. Trong nghiên cứu này, chúng tôi tiến hành giải trình tự hai gen này bằng Ion Torrent PGM. Đối tượng nghiên cứu là 11 mẫu mô vùi nến được thu nhận từ Bệnh viện Từ Dũ của 11 bệnh nhân ung thư biểu mô buồng trứng. DNA từ các mẫu này và 2 mẫu đối chứng đã biết thông tin đột biến được tiến hành multilplex PCR với kit Oncomine BRCA Research Assay. Trong mười một mẫu được giải trình tự, một đột biến gây bệnh (1/11 bệnh nhân; 9,1%) đã được phát hiện trên gen BRCA1, là đột biến điểm đưa codon stop vào trình tự protein tại vị trí axit amin 1772. Tóm lại, quy trình giải trình tự của chúng tôi thành công trong việc xác định và khảo sát tỉ lệ đột biến BRCA1/2 trong một nhóm nhỏ bệnh nhân ung thư biểu mô buồng trứng với mẫu sinh phẩm là mô vùi nến

Optimization of the calcination and two-step sintering temperatures of (K0.48Na0.48Li0.04)(Nb0.95Sb0.05)O3 ceramics

Lead-free (K _0.48 Na _0.48 Li _0.04 )(Nb _0.95 Sb _0.05 )O _3 (KNLNS) ceramics have been successfully optimized for the calcination and two-step sintering temperatures. The experimental results reveal that the KNLNS powder calcined at 850 or 900 °C presented a pure perovskite phase with an orthorhombic phase. The particle size was in the range of 0.1–0.4 μ m. The two-step sintering temperature (range: 950 to 1100 °C) significantly affects the structure, microstructure, and electrical properties of KNLNS ceramics. The presence of a pure perovskite phase with good crystallization is observed in all samples. The microstructure was researched by varying the two-step sintering temperature to obtain a dense microstructure and a clear grain boundary in order to optimize their piezoelectric properties. The best electrical properties of KNLNS ceramics were recorded at the optimized temperature of 1050 °C (density ( ρ ): 4,35 g cm ^−3 ; electromechanical coupling factor ( k _p ): 0.33, k _t : 0.35; dielectric constant ( ε _r ): 849; dielectric loss (tan δ ): 0.073; maximum dielectric constant ( ε _max at T _C ): 6659; piezoelectric constant ( d _33 ): 195 pC N ^−1 ; remanent polarization ( P _r ): 16.1 μ C cm ^−2 ; energy storage density ( W _rec ): 0.36 J cm ^−3 ; energy storage efficiency ( η ): 48.1%; t _2 = 4 h), proving the efficacy of the two-step sintering technique