Characteristics of shear strength at the interface between two soil layers in ring shear apparatus

The slopes containing discontinuous planes such as bedding planes, rupture, or boundary between two soil layers are often prone to sliding. Thus, the characteristics of shear strength mobilized along the discontinuous planes should be examined. In this study, the shear strength at the interface between two different soil layers will be investigated based on ring shear test. The combined sample comprising of one kaolin layer and one kaolin + bentonite mixture layer was used to simulate the discontinuous planes between two soil layers. A number of ring shear tests were conducted on these samples at a normal stress of 98 kPa and shear rates from 0.02 to 20 mm/min using a multi-stage of shearing rates procedure. The research results indicate that the shear strength at the interface sharply increases to reach the peak value after a small shear displacement, then drops to the residual value. The residual interface strength tends to increase with increasing shear rates above 2 mm/min and the level of increase in residual interface strength depends on the contact surface. Furthermore, the effect of the order sample layer in combined samples can be ignored when determining the peak, the residual interface strengths as well as the rate effect on residual interface strength in the laboratory

Characteristics of shear strength at the interface between two soil layers in ring shear apparatus

The slopes containing discontinuous planes such as bedding planes, rupture, or boundary between two soil layers are often prone to sliding. Thus, the characteristics of shear strength mobilized along the discontinuous planes should be examined. In this study, the shear strength at the interface between two different soil layers will be investigated based on ring shear test. The combined sample comprising of one kaolin layer and one kaolin + bentonite mixture layer was used to simulate the discontinuous planes between two soil layers. A number of ring shear tests were conducted on these samples at a normal stress of 98 kPa and shear rates from 0.02 to 20 mm/min using a multi-stage of shearing rates procedure. The research results indicate that the shear strength at the interface sharply increases to reach the peak value after a small shear displacement, then drops to the residual value. The residual interface strength tends to increase with increasing shear rates above 2 mm/min and the level of increase in residual interface strength depends on the contact surface. Furthermore, the effect of the order sample layer in combined samples can be ignored when determining the peak, the residual interface strengths as well as the rate effect on residual interface strength in the laboratory

Synthesis and photocatalytic property of Prussian blue/g-C3N4 composite applied to degradation of rhodamine B under visible light

In this work, the Prussian blue/g-C3N4 (PB/g-C3N4) composite was synthesized from Prussian blue and g-C3N4 via a simple method. The composite was characterized by using X-ray diffraction, Fourier-transform infrared spectroscopy, and ultraviolet-visible diffuse reflectance spectroscopy. The material’s photocatalytic performance was studied via the degradation of rhodamine B (RhB). The results show that the composite degraded RhB more than pristine Prussian blue under visible light after 60 min. This material is promising for organic waste treatment

Research on chemical constituents, anti-bacterial and anti-cancer effects of components isolated from Zingiber officinale Roscoe from Vietnam

Ginger, a commonly used spice and medicinal herb, is an abundant source of bioactive compounds. However, the utilization of ginger in the pharmaceutical industry is still moderate and not commensurate with the potential of the Vietnamese horticulture industry, mainly due to a lack of information about the quality of input materials. In this study, we compared the volatile compounds of gingers collected from 13 provinces of Vietnam using GC/MS and GC-FID analysis to provide a basis for selecting and standardizing input materials. Furthermore, ginger essential oil from Ben Tre province of Vietnam exhibited significant antibacterial activity particularly in inhibiting Gram-positive bacteria, including S. aureus and S. epidermidis, with inhibition zones of 30.00 ± 1.41 and 24.67 ± 3.30 mm, respectively. However, no significant inhibition was observed against Gram-negative bacteria P. aeruginosa and E. coli. We also isolated 5 non-volatile compounds from ginger extract, namely 6-shogaol (1), quercetin (2), rutin (3), beta-sitosterol (4) and beta-sitosterol-3-O-beta-D-glucopyranoside (5). Among them, compounds 1–3 displayed cytotoxicity against Hep3B, SK-LU-1, MCF-7, SK-LU-1, SW480 and HepG2 tumour cell lines, with an IC50 values ranging between 62.7 ± 2.1 and 97.6 ± 1.1 µM, using Ellipticine as a positive control. Compounds 4 and 5 showed cytotoxicity against Hep3B and HepG2 tumor cells, with the IC50 values ranging between 21.5 ± 5.1 and 46.9 ± 3.7 µM but did not exhibit any significant cytotoxicity against SW480 and SK-LU-1 cells. Compound 4 also demonstrated middling cytotoxicity against the MCF7 cell line, with an IC50 value of 43.6 ± 5.1 µM. These findings suggest further applications of Vietnamese ginger for the treatment of infectious and cancer-related diseases

Spatiotemporal evolution of SARS-CoV-2 Alpha and Delta variants during large nationwide outbreak of COVID-19, Vietnam, 2021

We analyzed 1,303 SARS-CoV-2 whole-genome sequences from Vietnam, and found the Alpha and Delta variants were responsible for a large nationwide outbreak of COVID-19 in 2021. The Delta variant was confined to the AY.57 lineage and caused >1.7 million infections and >32,000 deaths. Viral transmission was strongly affected by nonpharmaceutical interventions

Mental health and its determinants among adolescents living in families with separated or divorced parents in an urban area of Vietnam

Objectives We assessed the prevalence of stress, anxiety, and depression among adolescents living in families with separated or divorced parents in Hue City, Vietnam and identified factors associated with these conditions. Methods This cross-sectional study enrolled 309 adolescents, aged 12 to 17 years, living in families with separated or divorced parents in Hue City, Vietnam. The depression anxiety stress scale-21 (DASS-21) was used to measure stress, anxiety, and depression. Predictors of overall and individual mental health problems were identified using ordered and binary logistic regression, respectively. Results The DASS-21 scale revealed a 49.2% prevalence of stress, while anxiety and depression had s prevalence rates of 61.5%. Among participants, 42.4% experienced all 3 mental health issues. Several factors were identified as significant predictors of mental health problems, including poor to average economic status (adjusted odds ratio [aOR], 2.00; 95% confidence interval [CI], 1.21–3.31; p=0.007); being in high school (aOR, 5.02; 95% CI, 2.93–8.60; p<0.001); maternal occupation of teacher, healthcare professional, or official (aOR, 2.39; 95% CI, 1.13–5.03; p=0.022); longer duration of family separation or divorce (aOR, 1.24; 95% CI, 1.05–1.45; p=0.009); living with one’s mother (aOR, 1.69; 95% CI, 1.03–2.76; p=0.04); alcohol consumption (aOR, 1.70; 95% CI, 0.99–2.92; p=0.050); and being bullied (aOR, 5.33; 95% CI, 1.10–25.69; p=0.037). Most of these factors were associated with stress, anxiety, and depression. Additionally, smoking was associated with stress. Conclusion Adolescents with separated or divorced parents were at increased risk of stress, anxiety, and depression. The findings of this study provide important implications for prevention programs

preliminary remarks on assembly whole genome sequencing of mdr m tuberculosis isolated in vietnam

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A Bibliometric Analysis of the Global Research Trend in Child Maltreatment

Child maltreatment remains a major health threat globally that requires the understanding of socioeconomic and cultural contexts to craft effective interventions. However, little is known about research agendas globally and the development of knowledge-producing networks in this field of study. This study aims to explore the bibliometric overview on child maltreatment publications to understand their growth from 1916 to 2018. Data from the Web of Science Core Collection were collected in May 2018. Only research articles and reviews written in the English language were included, with no restrictions by publication date. We analyzed publication years, number of papers, journals, authors, keywords and countries, and presented the countries collaboration and co-occurrence keywords analysis. From 1916 to 2018, 47, 090 papers (53.0% in 2010–2018) were published in 9442 journals. Child Abuse & Neglect (2576 papers; 5.5%); Children and Youth Services Review (1130 papers; 2.4%) and Pediatrics (793 papers, 1.7%) published the most papers. The most common research areas were Psychology (16, 049 papers, 34.1%), Family Studies (8225 papers, 17.5%), and Social Work (7367 papers, 15.6%). Among 192 countries with research publications, the most prolific countries were the United States (26, 367 papers), England (4676 papers), Canada (3282 papers) and Australia (2664 papers). We identified 17 authors who had more than 60 scientific items. The most cited papers (with at least 600 citations) were published in 29 journals, headed by the Journal of the American Medical Association (JAMA) (7 papers) and the Lancet (5 papers). This overview of global research in child maltreatment indicated an increasing trend in this topic, with the world’s leading centers located in the Western countries led by the United States. We called for interdisciplinary research approaches to evaluating and intervening on child maltreatment, with a focus on low-middle income countries (LMICs) settings and specific contexts

Awareness and preparedness of healthcare workers against the first wave of the COVID-19 pandemic: A cross-sectional survey across 57 countries.

BACKGROUND: Since the COVID-19 pandemic began, there have been concerns related to the preparedness of healthcare workers (HCWs). This study aimed to describe the level of awareness and preparedness of hospital HCWs at the time of the first wave. METHODS: This multinational, multicenter, cross-sectional survey was conducted among hospital HCWs from February to May 2020. We used a hierarchical logistic regression multivariate analysis to adjust the influence of variables based on awareness and preparedness. We then used association rule mining to identify relationships between HCW confidence in handling suspected COVID-19 patients and prior COVID-19 case-management training. RESULTS: We surveyed 24,653 HCWs from 371 hospitals across 57 countries and received 17,302 responses from 70.2% HCWs overall. The median COVID-19 preparedness score was 11.0 (interquartile range [IQR] = 6.0-14.0) and the median awareness score was 29.6 (IQR = 26.6-32.6). HCWs at COVID-19 designated facilities with previous outbreak experience, or HCWs who were trained for dealing with the SARS-CoV-2 outbreak, had significantly higher levels of preparedness and awareness (p<0.001). Association rule mining suggests that nurses and doctors who had a 'great-extent-of-confidence' in handling suspected COVID-19 patients had participated in COVID-19 training courses. Male participants (mean difference = 0.34; 95% CI = 0.22, 0.46; p<0.001) and nurses (mean difference = 0.67; 95% CI = 0.53, 0.81; p<0.001) had higher preparedness scores compared to women participants and doctors. INTERPRETATION: There was an unsurprising high level of awareness and preparedness among HCWs who participated in COVID-19 training courses. However, disparity existed along the lines of gender and type of HCW. It is unknown whether the difference in COVID-19 preparedness that we detected early in the pandemic may have translated into disproportionate SARS-CoV-2 burden of disease by gender or HCW type