Synthesis and spectral studies of complexes between palladium and some thiosemicarbazones

This paper reviews the synthesis and spectral studies of some complexes of palladium with thiosemicarbazones: Pd(L1)NH3 (L1: pyruvic acid thiosemicarbazone) and Pd(Li)2), (i: 2-4, thiosemicarbazone of: acetophenone (L2), benzaldehyde (L3), p-dimethylaminobenzaldehyde(L4)). The ligands and complexes are characterized by means of chemical analysis, thermal analysis, IR, ESI-MS and 1H-NMR spectroscopy. The obtained data show that in Pd(L1)NH3, three coordinate sites are realized by S, N(1) and O-atoms of  L1 and the fourth coordinate site  by NH3-group; in Pd(Li)2) complexes, Li acts as anionic bidentate ligands, two coordinate bonds realize through S and N(1) atoms. Especially, the obtained data 1H-NMR spectrum of Pd(L2)2 indicate that this complex exists in two isomers, supposed to be cis and trans, in DMSO solutions

Evaluation of the changes of the shoreline in Cua Tung in Quang Tri province before and after the construction of groin on the south riverbank of Ben Hai river

The process of erosion-sedimentation of Cua Tung, Quang Tri province has been mentioned in previous studies, but there have been no studies that apply satellite images to evaluate the changes of shoreline before and after the construction of groin along the south of Ben Hai river. This paper aims to evaluate the changes and rate of erosion - sedimentation of Cua Tung shoreline before and after the construction, using Landsat satellite images from 1990 to 2017. We used Envi 5.0 to analyse and interpret multiple-spectral Landsat satellite images in combination with analysis algorithm to identify the shoreline change over the years by adopting the ratio image method by Gathot Winasor to separate water zone and shoreline zone automatically. We then calculated the rate of shoreline changes by the function DSAS (Digital Shoreline Analysis System) proposed by Thieler et al., in Avenue programming language in ArcView software. The results showed that the process of erosion-sedimentation in Cua Tung-Quang Tri from 1990 to 2017 was divided into 6 stages in which the stage of 2000–2005 had the clearest indication in the process of erosion-sedimentation. This research has demonstrated that GIS and remote sensing technologies have been good tools to assist policy maker in their decision-making to properly evaluate erosion-sedimentation in Cua Tung- Quang Tri, so that appropriate solutions will be delivered to guarantee the local socio-economic sustainable development

Assessment of physical land suitability by GIS-based fuzzy AHP for rubber plantation at the Nam Dong district, Thua Thien Hue province

This research was conducted to determine the main influences and physical factors of land suitability for rubber plantation in the Nam Dong district, Thua Thien Hue province. Six factors such as soil type, soil texture, soil thickness, slope, soil pH and soil organic matter content were considered. Results indicate that soil thickness is has the highest role on the land suitability analysis while soil pH has the lowest. The physical land suitability of rubber plantation was divided into 4 levels: very suitable (10.1%), suitable (15.5%), slightly suitable (3.6%), and currently not suitable (70,8%). This research provides important information for rubber cultivation in projected agricultural land use planning of the Nam Dong district.Nghiên cứu này được thực hiện nhằm xác định sự ảnh hưởng của các yếu tố tự nhiên đến sự thích nghi đất đai của loại hình sử dụng đất trồng cây cao su trên địa bàn huyện Nam Đông, tỉnh Thừa Thiên Huế. Có 6 yếu tố được xem xét trong nghiên cứu này bao gồm: loại đất, thành phần cơ giới, tầng dày canh tác, độ dốc, độ chua và hàm lượng mùn trong đất. Kết quả nghiên cứu chỉ ra rằng tầng dày canh tác là yếu tố có ảnh hưởng lớn nhất đến việc sử dụng đất trồng cây cao su, trong khi đó độ chua là yếu tố có ảnh hưởng ít nhất. Sự thích nghi tự nhiên của loại hình sử dụng đất trồng cây cao su được chia thành 4 mức độ bao gồm rất thích nghi (10,1%), thích nghi (15,5%), tương đối thích nghi (3,6%) và hiện taị không thích nghi (70,8%). Nghiên cứu này cung cấp những thông tin cần thiết và hữu ích cho việc quy hoạch sử dụng đất trồng cây cao su trên địa bàn huyện Nam Đông

Targeted sequencing from cerebrospinal fluid for rapid identification of drug-resistant tuberculous meningitis

Mortality from tuberculous meningitis (TBM) remains around 30%, with most deaths occurring within 2 months of starting treatment. Mortality from drug-resistant strains is higher still, making early detection of drug resistance (DR) essential. Targeted next-generation sequencing (tNGS) produces high read depths, allowing the detection of DR-associated alleles with low frequencies. We applied Deeplex Myc-TB-a tNGS assay-to cerebrospinal fluid (CSF) samples from 72 adults with microbiologically confirmed TBM and compared its genomic drug susceptibility predictions to a composite reference standard of phenotypic susceptibility testing (pDST) and whole genome sequencing, as well as to clinical outcomes. Deeplex detected Mycobacterium tuberculosis complex DNA in 24/72 (33.3%) CSF samples and generated full DR reports for 22/24 (91.7%). The read depth generated by Deeplex correlated with semi-quantitative results from MTB/RIF Xpert. Alleles with <20% frequency were seen at canonical loci associated with first-line DR. Disregarding these low-frequency alleles, Deeplex had 100% concordance with the composite reference standard for all drugs except pyrazinamide and streptomycin. Three patients had positive CSF cultures after 30 days of treatment; reference tests and Deeplex identified isoniazid resistance in two, and Deeplex alone identified low-frequency rifampin resistance alleles in one. Five patients died, of whom one had pDST-identified pyrazinamide resistance. tNGS on CSF can rapidly and accurately detect drug-resistant TBM, but its application is limited to those with higher bacterial loads. In those with lower bacterial burdens, alternative approaches need to be developed for both diagnosis and resistance detection

A novel diagnostic model for tuberculous meningitis using Bayesian latent class analysis

Background Diagnosis of tuberculous meningitis (TBM) is hampered by the lack of a gold standard. Current microbiological tests lack sensitivity and clinical diagnostic approaches are subjective. We therefore built a diagnostic model that can be used before microbiological test results are known. Methods We included 659 individuals aged ≥ 16 years with suspected brain infections from a prospective observational study conducted in Vietnam. We fitted a logistic regression diagnostic model for TBM status, with unknown values estimated via a latent class model on three mycobacterial tests: Ziehl–Neelsen smear, Mycobacterial culture, and GeneXpert. We additionally re-evaluated mycobacterial test performance, estimated individual mycobacillary burden, and quantified the reduction in TBM risk after confirmatory tests were negative. We also fitted a simplified model and developed a scoring table for early screening. All models were compared and validated internally. Results Participants with HIV, miliary TB, long symptom duration, and high cerebrospinal fluid (CSF) lymphocyte count were more likely to have TBM. HIV and higher CSF protein were associated with higher mycobacillary burden. In the simplified model, HIV infection, clinical symptoms with long duration, and clinical or radiological evidence of extra-neural TB were associated with TBM At the cutpoints based on Youden’s Index, the sensitivity and specificity in diagnosing TBM for our full and simplified models were 86.0% and 79.0%, and 88.0% and 75.0% respectively. Conclusion Our diagnostic model shows reliable performance and can be developed as a decision assistant for clinicians to detect patients at high risk of TBM. Summary Diagnosis of tuberculous meningitis is hampered by the lack of gold standard. We developed a diagnostic model using latent class analysis, combining confirmatory test results and risk factors. Models were accurate, well-calibrated, and can support both clinical practice and research

Differential prevalence and geographic distribution of hepatitis C virus genotypes in acute and chronic hepatitis C patients in Vietnam.

BACKGROUND: The highest burden of disease from hepatitis C virus (HCV) is found in Southeast Asia, but our understanding of the epidemiology of infection in many heavily burdened countries is still limited. In particular, there is relatively little data on acute HCV infection, the outcome of which can be influenced by both viral and host genetics which differ within the region. We studied HCV genotype and IL28B gene polymorphism in a cohort of acute HCV-infected patients in Southern Vietnam alongside two other cohorts of chronic HCV-infected patients to better understand the epidemiology of HCV infection locally and inform the development of programs for therapy with the increasing availability of directly acting antiviral therapy (DAAs). METHODS: We analysed plasma samples from patients with acute and chronic HCV infection, including chronic HCV mono-infection and chronic Human Immunodeficiency Virus (HIV)-HCV coinfection, who enrolled in four epidemiological or clinical research studies. HCV infection was confirmed with RNA testing. The 5' UTR, core and NSB5 regions of HCV RNA positive samples were sequenced, and the genotype and subtype of the viral strains were determined. Host DNA from all HCV positive patients and age- and sex-matched non-HCV-infected control individuals were analysed for IL28B single nucleotide polymorphism (SNP) (rs12979860 and rs8099917). Geolocation of the patients were mapped using QGIS. RESULTS: 355 HCV antibody positive patients were analysed; 54.6% (194/355) and 46.4% (161/355) were acute and chronic infections, respectively. 50.4% (81/161) and 49.6.4% (80/161) of chronic infections had HCV mono-infection and HIV-HCV coinfection, respectively. 88.7% (315/355) and 10.1% (36/355) of the patients were from southern and central regions of Vietnam, respectively. 92.4% (328/355) of patients were HCV RNA positive, including 86.1% (167/194) acute and 100% (161/161) chronic infections. Genotype could be determined in 98.4% (322/328) patients. Genotypes 1 (56.5%; 182/322) and 6 (33.9%; 109/322) predominated. Genotype 1 including genotype 1a was significantly higher in HIV-HCV coinfected patients compared to acute HCV patients [43.8% (35/80) versus 20.5% (33/167)], (p = <0.001), while genotype 6 was significantly higher in chronic HCV mono-infected patients [(44.4% (36/81) versus 20.0% (16/80)] (p = < 0.004) compared to HIV-HCV coinfected patients. The prevalence of IL28B SNP (rs12979860) homozygous CC was 86.46% (83/96) in control individuals and was significantly higher in acutely-infected compared to chronically-infected patients [93.2 (82/88) versus 76.1% (35/46)] (p = < 0.005). CONCLUSION: HCV genotype 6 is highly prevalent in Vietnam and the high prevalence in treatment naïve chronic HCV patients may results from poor spontaneous clearance of acute HCV infection with genotype 6

The identification of enteric fever-specific antigens for population based serosurveillance

Background Enteric fever, caused by Salmonella enterica serovars Typhi and Paratyphi A, is a major public health problem in low and middle-income countries. Moderate sensitivity and scalability of current methods likely underestimate enteric fever burden. Determining the serological responses to organism-specific antigens may improve incidence measures. Methods Plasma samples were collected from blood culture-confirmed enteric fever patients, blood culture-negative febrile patients over the course of three months and afebrile community controls. A panel of 17 Salmonella Typhi and Paratyphi A antigens was purified and used to determine antigen-specific antibody responses by indirect ELISAs. Results The antigen-specific longitudinal antibody responses were comparable between enteric fever patients, patients with blood culture-negative febrile controls, and afebrile community controls for most antigens. However, we found that IgG responses against STY1479 (YncE), STY1886 (CdtB), STY1498 (HlyE) and the serovar-specific O2 and O9 antigens were greatly elevated over a three-month follow up period in S. Typhi/S. Paratyphi A patients compared to controls, suggesting seroconversion. Conclusions We identified a set of antigens as good candidates to demonstrate enteric fever exposure. These targets can be used in combination to develop more sensitive and scalable approaches to enteric fever surveillance and generate invaluable epidemiological data for informing vaccine policies

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

Acceptance and user experiences of a wearable device for the management of hospitalized patients in COVID-19–designated wards in Ho Chi Minh City, Vietnam: action learning project

Background: Wearable devices have been used extensively both inside and outside of the hospital setting. During the COVID-19 pandemic, in some contexts, there was an increased need to remotely monitor pulse and saturated oxygen for patients due to the lack of staff and bedside monitors. Objective: A prototype of a remote monitoring system using wearable pulse oximeter devices was implemented at the Hospital for Tropical Diseases in Ho Chi Minh City, Vietnam, from August to December 2021. The aim of this work was to support the ongoing implementation of the remote monitoring system. Methods: We used an action learning approach with rapid pragmatic methods, including informal discussions and observations as well as a feedback survey form designed based on the technology acceptance model to assess the use and acceptability of the system. Based on these results, we facilitated a meeting using user-centered design principles to explore user needs and ideas about its development in more detail. Results: In total, 21 users filled in the feedback form. The mean technology acceptance model scores ranged from 3.5 (for perceived ease of use) to 4.4 (for attitude) with behavioral intention (3.8) and perceived usefulness (4.2) scoring in between. Those working as nurses scored higher on perceived usefulness, attitude, and behavioral intention than did physicians. Based on informal discussions, we realized there was a mismatch between how we (ie, the research team) and the ward teams perceived the use and wider purpose of the technology. Conclusions: Designing and implementing the devices to be more nurse-centric from their introduction could have helped to increase their efficiency and use during the complex pandemic period