90 research outputs found
Harnessing graph state resources for robust quantum magnetometry under noise
Precise measurement of magnetic fields is essential for various applications,
such as fundamental physics, space exploration, and biophysics. Although recent
progress in quantum engineering has assisted in creating advanced quantum
magnetometers, there are still ongoing challenges in improving their efficiency
and noise resistance. This study focuses on using symmetric graph state
resources for quantum magnetometry to enhance measurement precision by
analyzing the estimation theory under Markovian and non-Markovian noise models.
The results show a significant improvement in estimating both single and
multiple Larmor frequencies. In single Larmor frequency estimation, the quantum
Fisher information spans a spectrum from the standard quantum limit to the
Heisenberg limit within a periodic range of the Larmor frequency, and in the
case of multiple Larmor frequencies, it can exceed the standard quantum limit
for both Markovian and non-Markovian noise. This study highlights the potential
of graph state-based methods for improving magnetic field measurements under
noisy environments.Comment: 10 pages, 7 figure
Monitoring of coastline change using Sentinel-2 MSI data. A case study in Thanh Hoa Province, Vietnam
Vietnam is a coastal country with a coastline of more than 3,260 km, stretching from north to south. Coastal change in Vietnam is complicated further by the effects of climate change, including erosion and accretion, causing great impacts on infrastructure and the environment. This article presents the results of assessing coastline changes in Thanh Hoa Province (North Central region of Vietnam) from Sentinel-2 MSI satellite image data for the period 2015–23. Three Sentinel-2 MSI images taken in December 2015, December 2020 and December 2023 were used to calculate the water indices, including Normalised Difference Water Index (NDWI), Modified Normalised Difference Water Index (MNDWI) Argumented Normalised Difference Water Index (ANDWI) and Automated Water Extraction Index (AWEIsh), then extract the shoreline using the thresholding method and select the water index with the highest accuracy through comparing the overall accuracy and Kappa coefficient. The coastlines of 2015, 2020 and 2023 years are overlaid to evaluate the coastal changes in the study area. The results received in the study provide objective and timely information, helping managers effectively monitor and respond to coastline changes
Mapping impervious surface change from remote sensing and GIS data: A case study in Hochiminh city, Vietnam
Impervious surface is artificial surfaces that prevent water from entering the soil. The increase in impervious surface area has led to negative impacts on the urban environment, including an increase in the risk of flooding, a decrease in vegetation cover, and the formation of urban heat islands. This paper presents the results of building a predictive model of impervious surfaces in Hochiminh city from remote sensing and GIS data. Landsat and Sentinel 2 satellite images for the period 2002–2022 are used to classify impervious surfaces and extract input layers about vegetation cover, land surface temperature, combined with GIS data (elevation, slope, aspect, distance to road, distance to hydrology, population density) for modeling and predicting impervious surface changes in future. 03 machine learning algorithms, including Support Vector Machine (SVM), Random Forest (RF), Classification and Regression Trees (CART) and maximum likelihood method are used to classify impervious surfaces from Landsat satellite images, then select the method with the highest accuracy. To predict the future distribution of impervious surface, this study uses Cellular Automata (CA) model and 02 artificial intelligence algorithms (Artificial Neural Network - ANN, Logistic Regression - LR). The results obtained in the study can be effectively used for urban planning, minimizing the impact of the process of increasing the impervious surface on the urban environmen
Geo-chemical fractionations of arsenic and lead in the surface sediments of Thuy Trieu lagoon, Khanh Hoa province
The sequential extraction method of Tessier et al. was applied to identify the phase associations of As and Pb in the surface sediment of Thuy Trieu lagoon. The results showed that these two metals were mainly found in the residual fractions. Meanwhile, the carbonate fractions stayed at the lowest portions. Levels of arsenic and lead as Fe-Mn oxide fractions were higher than those as organic fractions and exchangeable fractions. Exchangeable fractions and carbonate fractions of two elements seemed to increase in rainy season. Generally, the mobility of Pb was higher than that of As. In the sediments of Thuy Trieu lagoon, Pb levels cannot currently cause adverse effects on the ecosystems. On the contrary, the risk of As was assessed as moderate level
Medicinal Plants Used by the Tay Ethnic Group, Thai Nguyen Province, Vietnam
An ethnobotanical study of medicinal plants used by the Tay ethnic group in Thai Nguyen province, Vietnam has been carried out in the present study, especially in the region of Định Hoá, Phú Lương, and Võ Nhai districts. The ethnobotanical survey was conducted between 2018 and 2021 and a catalog of the medicinal plant used by the Tay ethnic group is prepared. The results of the current survey revealed that the plants used by Tay ethnic group consist of 321 species belonging to 253 genera and 103 botanical families. Majority of the plants belonging the family Euphorbiaceae (20 species), Asteraceae (19 species), Acanthaceae and Rutaceae (13 species each), Fabaceae (12 species), and Poaceae (11 species). Leaves were the most frequently used plant part (48.0%) in the preparation of medicines. The most frequent preparation method was decoction (47.7%), followed by crushing (29.9%), sauna (18.0), pickle wine (11.8%), and raw (5.6%). The major plant used by Tay ethnic people were Schefflera heptaphylla (L.) Frodin and Plantago major L., (2); Elephantopus scaber L. and Achyranthes aspera L.; Streblus asper Lour. We also carried out screening of some of the medicinal plant extracts for their biological activities especially the inhibition of cancer cell lines
Evaluation of Luminex xTAG Gastrointestinal Pathogen Panel Assay for Detection of Multiple Diarrheal Pathogens in Fecal Samples in Vietnam.
Diarrheal disease is a complex syndrome that remains a leading cause of global childhood morbidity and mortality. The diagnosis of enteric pathogens in a timely and precise manner is important for making treatment decisions and informing public health policy, but accurate diagnosis is a major challenge in industrializing countries. Multiplex molecular diagnostic techniques may represent a significant improvement over classical approaches. We evaluated the Luminex xTAG gastrointestinal pathogen panel (GPP) assay for the detection of common enteric bacterial and viral pathogens in Vietnam. Microbiological culture and real-time PCR were used as gold standards. The tests were performed on 479 stool samples collected from people admitted to the hospital for diarrheal disease throughout Vietnam. Sensitivity and specificity were calculated for the xTAG GPP for the seven principal diarrheal etiologies. The sensitivity and specificity for the xTAG GPP were >88% for Shigellaspp.,Campylobacterspp., rotavirus, norovirus genotype 1/2 (GI/GII), and adenovirus compared to those of microbiological culture and/or real-time PCR. However, the specificity was low (∼60%) for Salmonella species. Additionally, a number of important pathogens that are not identified in routine hospital procedures in this setting, such as Cryptosporidiumspp. and Clostridium difficile, were detected with the GPP. The use of the Luminex xTAG GPP for the detection of enteric pathogens in settings, like Vietnam, would dramatically improve the diagnostic accuracy and capacity of hospital laboratories, allowing for timely and appropriate therapy decisions and a wider understanding of the epidemiology of pathogens associated with severe diarrheal disease in low-resource settings
NGHIÊN CỨU CHẨN ĐOÁN PASTEURELLA MULTOCIDA VÀ MANNHEIMIA HAEMOLYTICA BẰNG KỸ THUẬT MULTIPLEX PCR
The multiplex PCR assay has been used to diagnose different diseases in livestock in Vietnam; however, this method has not been well-applied to sheep diseases. This study developed a multiplex PCR assay to detect the two main agents, Pasteurella multocida and Mannheimia haemolytica, causing Pasteurellosis in sheep. By using two pairs of specific primers, with the optimum concentration of each primer being 5 pM, this method successfully amplified the kmt1 gene from P. multocida and the gcp gene from M. haemolytica in the same reaction containing DNA of P. multocida and M. haemolytica at the lowest concentration of 0.1 ng each. Moreover, this multiplex PCR reaction is not affected by the artificial presence of some other bacterial DNA. In particular, this multiplex PCR showed 100% confidence in a stability test on a small scale with 20 raw DNA samples obtained from direct heat treatment or enrichment before heat treatment of 10 field samples. This is the first study in Vietnam on diagnosing P. multocida and M. haemolytica by multiplex PCR. This method is valuable for detecting P. multocida and M. haemolytica in sheep and serves as a reference for detecting these bacteria in other household animal.Ở Việt Nam, kỹ thuật multiplex PCR đã được sử dụng để chẩn đoán nhiều bệnh trên vật nuôi nhưng kỹ thuật này hiện nay chưa được áp dụng để chẩn đoán bệnh trên cừu. Trong nghiên cứu này, chúng tôi đã phát triển một kỹ thuật multiplex PCR để phát hiện đồng thời hai tác nhân chính gây tụ huyết trùng trên cừu Phan Rang là Pasteurella multocida và Mannheimia haemolytica. Bằng cách sử dụng hai cặp mồi đặc hiệu, với nồng độ tối ưu của mỗi mồi là 5 pM, phương pháp này đã nhân thành công đoạn gen kmt1 từ P. multocida và gcp từ M. haemolytica trong cùng một phản ứng chứa hỗn hợp DNA tổng số của hai vi khuẩn này ở nồng độ thấp nhất là 0,1 ng mỗi loại. Thêm vào đó, phản ứng multiplex PCR này không bị ảnh hưởng bởi sự có mặt nhân tạo của một số DNA từ vi khuẩn khác. Đặc biệt, phương pháp multiplex PCR này có độ ổn định đạt 100% khi thử nghiệm trên quy mô nhỏ với 20 mẫu DNA thô thu được từ phương pháp xử lý nhiệt trực tiếp hay xử lý nhiệt sau khi làm giàu 10 mẫu thực địa. Đây là nghiên cứu đầu tiên ở Việt Nam về việc chẩn đoán tụ huyết trùng trên cừu bằng kỹ thuật multiplex PCR, kỹ thuật không chỉ có giá trị để phát hiện vi khuẩn P. multocida và M. haemolytica ở cừu mà còn có vai trò tham khảo để chẩn đoán những vi khuẩn này trong các đối tượng vật nuôi khác
Rifampicin resistant 'Mycobacterium tuberculosis' in Vietnam, 2020–2022
Objective: We conducted a descriptive analysis of multi-drug resistant tuberculosis (MDR-TB) in Vietnam’s two largest cities, Hanoi and Ho Chi Minh city.
Methods: All patients with rifampicin resistant tuberculosis were recruited from Hanoi and surrounding provinces between 2020 and 2022. Additional patients were recruited from Ho Chi Minh city over the same time period. Demographic data were recorded from all patients, and samples collected, cultured, whole genome sequenced and analysed for drug resistance mutations. Genomic susceptibility predictions were made on the basis of the World Health Organization’s catalogue of mutations in Mycobacterium tuberculosis associated with drug resistance, version 2. Comparisons were made against phenotypic drug susceptibility test results where these were available. Multivariable logistic regression was used to assess risk factors for previous episodes of tuberculosis.
Results: 233/265 sequenced isolates were of sufficient quality for analysis, 146 (63 %) from Ho Chi Minh City and 87 (37 %) from Hanoi. 198 (85 %) were lineage 2, 20 (9 %) were lineage 4, and 15 (6 %) were lineage 1. 17/211 (8 %) for whom HIV status was known were infected, and 109/214 (51 %) patients had had a previous episode of tuberculosis. The main risk factor for a previous episode was HIV infection (odds ratio 5.1 (95 % confidence interval 1.3–20.0); p = 0.021). Sensitivity for predicting first-line drug resistance from whole genome sequencing data was over 90 %, with the exception of pyrazinamide (85 %). For moxifloxacin and amikacin it was 50 % or less. Among rifampicin-resistant isolates, prevalence of resistance to each non-first-line drug was < 20 %.
Conclusions: Drug resistance among most MDR-TB strains in Vietnam’s two largest cities is confined largely to first-line drugs. Living with HIV is the main risk factor among patients with MDR-TB for having had a previous episode of tuberculosis
An open label randomized controlled trial of tamoxifen combined with amphotericin B and fluconazole for cryptococcal meningitis
Background: Cryptococcal meningitis has high mortality. Flucytosine is a key treatment but is expensive and rarely available. The anti-cancer agent tamoxifen has synergistic anti-cryptococcal activity with amphotericin in vitro. It is off-patent, cheap, and widely available. We performed a trial to determine its therapeutic potential.
Methods:Open label randomized controlled trial. Participants received standard care - amphotericin combined with fluconazole for the first two weeks - or standard care plus tamoxifen 300mg/day. The primary end point was Early Fungicidal Activity (EFA) - the rate of yeast clearance from cerebrospinal fluid (CSF). Trial registration https://clinicaltrials.gov/ct2/show/NCT03112031 .
Results: 50 patients were enrolled, (median age 34 years, 35 male). Tamoxifen had no effect on EFA (- 0.48log10 colony-forming units/mL/CSF control arm versus -0.49 tamoxifen arm, difference - 0.005log10CFU/ml/day, 95%CI: -0.16, 0.15, P=0.95). Tamoxifen caused QTc prolongation.
Conclusion: High dose tamoxifen does not increase the clearance rate of Cryptococcus from CSF. Novel, affordable therapies are needed.
Funding:The trial was funded through the Wellcome Trust Asia Programme Vietnam Core Grant 106680 and a Wellcome Trust Intermediate Fellowship to JND grant number WT097147MA
ĐẶC ĐIỂM HÌNH THÁI VÀ ĐẶC ĐIỂM VI HỌC CỦA LOÀI BA KÍCH TÍM (Morinda officinalis How.) THU HÁI TẠI TỈNH THỪA THIÊN HUẾ
Morinda officinalis How. is a medicinal plant that has been studied and used for a long time. Previous studies on M. officinalis primarily focused on the source in the northern provinces of Vietnam. This study is the first one on the botanical characteristics, including morphology, anatomy, and powder microscopy of M. officinalis in Thua Thien Hue province. Morphological and microscopic characteristics were determined by comparing the shape and double-staining and observing under a microscope through 10× and 40× objective lenses. The results show the similarities and differences of M. officinalis in Thua Thien Hue and other regions of Vietnam. Particularly, the root of M. officinalis in Thua Thien Hue has a higher percentage of usable parts than other M. officinalis species in northern regions. Furthermore, the results of the study provide scientific data for learning and investigating the morphological and microscopic characteristics of M. officinalis in Thua Thien Hue.Ba kích tím (Morinda officinalis How.) là một loài dược liệu quý được nghiên cứu và sử dụng từ rất lâu đời. Các nghiên cứu về Ba kích tím trước đây chủ yếu tập trung vào nguồn giống thu hái tại các tỉnh phía Bắc của Việt Nam. Nghiên cứu này là công trình đầu tiên về đặc điểm thực vật bao gồm hình thái, vi phẫu và soi bột của cây Ba kích tím được thu hái tại môi trường tự nhiên của tỉnh Thừa Thiên Huế. Đặc điểm hình thái và đặc điểm vi học được nghiên cứu bằng phương pháp so sánh hình thái và nhuộm kép và quan sát dưới kính hiển vi qua vật kính 10× và 40×. Kết quả nghiên cứu cho thấy sự tương đồng và khác biệt chính về đặc điểm thực vật của cây Ba kích tím giữa Thừa Thiên Huế và các vùng miền khác ở Việt Nam. Đặc biệt, rễ củ Ba kích tím tại Thừa Thiên Huế có tỷ lệ bộ phận sử dụng nhiều hơn so với các loài Ba kích tím tại khu vực phía Bắc. Kết quả của bài báo góp phần cung cấp dữ liệu khoa học cho học tập và nghiên cứu về đặc điểm hình thái và vi học của loài Ba kích tím ở Thừa Thiên Huế
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