Predicted multiple charge density wave phases in monolayer 1T-NbO2.

Layered transition-metal dichalcogenides, such as NbSe2, have been extensively studied for almost half a century due to their intriguing properties, such as charge density wave (CDW) and superconductivity. Can the layered transition-metal dioxide, such as NbO2, be stable and exhibit CDW, given that it has the same crystal structure and electronic configuration as NbSe2? Here, we use first-principles calculations to predict that 1T-NbO2is possibly stable at high temperatures, but it would undergo two CDW transitions with12×12and13×13periodicities at low temperatures. Both CDW transitions are accompanied by a metal-semiconductor transition. Notably, the13×13CDW phase of NbO2possesses localized magnetic moments and hosts a Mott insulating state. This work offers a fresh outlook on studying CDW and Mott transition in low-dimensional oxide materials.

Disease-specific data processing: An intelligent digital platform for diabetes based on model prediction and data analysis utilizing big data technology.

Background: Artificial intelligence technology has become a mainstream trend in the development of medical informatization. Because of the complex structure and a large amount of medical data generated in the current medical informatization process, big data technology to assist doctors in scientific research and analysis and obtain high-value information has become indispensable for medical and scientific research. Methods: This study aims to discuss the architecture of diabetes intelligent digital platform by analyzing existing data mining methods and platform building experience in the medical field, using a large data platform building technology utilizing the Hadoop system, model prediction, and data processing analysis methods based on the principles of statistics and machine learning. We propose three major building mechanisms, namely the medical data integration and governance mechanism (DCM), data sharing and privacy protection mechanism (DPM), and medical application and medical research mechanism (MCM), to break down the barriers between traditional medical research and digital medical research. Additionally, we built an efficient and convenient intelligent diabetes model prediction and data analysis platform for clinical research. Results: Research results from this platform are currently applied to medical research at Shanghai T Hospital. In terms of performance, the platform runs smoothly and is capable of handling massive amounts of medical data in real-time. In terms of functions, data acquisition, cleaning, and mining are all integrated into the system. Through a simple and intuitive interface operation, medical and scientific research data can be processed and analyzed conveniently and quickly. Conclusions: The platform can serve as an auxiliary tool for medical personnel and promote the development of medical informatization and scientific research. Also, the platform may provide the opportunity to deliver evidence-based digital therapeutics and support digital healthcare services for future medicine.

First Report of Bacterial Leaf Spot on Tobacco Caused by Pseudomonas psychrotolerans in China.

Tobacco (Nicotiana tabacum) is an economically important crop, and its productivity is challenged due to pathogen infection. In 2020 and 2021, a previously uncharacterized disease was observed on field grown tobacco (Variety NC102) in Zhucheng City, Shandong Province, China (119°7'14" E, 36°0'58" N), where tobacco has been grown for decades. The disease can be found throughout the growth period of tobacco and mainly occurred from fast growing period (about 13-16 leaves) to leaf maturity stage. In severely diseased areas, the incidence rate can reach 100%. The symptoms first began as chlorotic water stain like small spots, then the spots merged into larger irregular necrotic maculae around the chlorotic halos. Small pieces of symptomatic leaves from 10 different infected plants were collected for pathogen isolation. The small pieces of discolored leaves were surface sterilized with 75% ethanol for 40s and washed with sterile water for three times. The sterilized leaves were ground with a glass rod with 1mL sterile water, and 100 µL suspensions were spread on nutrient agar medium then incubated at 28oC for 48 hours. Yellow round colonies with undulating edges were showed up on nutrient agar medium 48 hours later. Three isolates were randomly picked up from each of the 10 plates for subsequent analysis. After purification and culture on nutrient agar plate, the 16S rRNA gene of the 30 isolates were amplified with primers 27F and 1492R and the amplicons were sequenced and analyzed by sequence alignment. The sequence alignment results showed that the 16S rRNA nucleotide identity of the 30 isolates were 100%. One typical isolate named ZC5 was selected for subsequent analysis, and the resulting 16S rRNA sequence was deposited at GenBank, NCBI under accession OK092624. The 16S rRNA sequence identity with those of P. psychrotolerans strain K3-2 (KY882083) and M3-1 (KY882120) were 100%, respectively. The phenotypic analysis by Biolog Gen Ⅲ indicated that the bacterial isolate (ZC5) showed highest similarity (98.3%) with strain Pseudomonas oryzihabitans. P. oryzihabitans and P. psychrotolerans have a high degree of homology in the phylogenetic relationship based on the phylogenetic analysis of three concatenated sequences of gyrB, rpoB and rpoD genes (Mulet et al. 2010). The gyrB (ON462356), rpoB (ON462355), rpoD (ON462357) gene of isolate ZC5were also amplified and sequenced by using primers gyrB-For/gyrB-Rev, rpoB-For/rpoB-Rev and rpoD-For/rpoD-Rev (Hauser et al. 2004), respectively. While P. psychrotolerans and P. oryzihabitans form the same clade in phylogenies, strains of P. psychrotolerans do form a unique sub-clade. Isolate ZC5 clustered more closely with the type strain of P. psychrotolerans LMG 21977 in the phylogenetic tree. Therefore, based on the concatenated sequences of three genes (gyrB, rpoB and rpoD), the isolate ZC5 was confirmed as P. psychrotolerans. Based on morphological, Biolog characteristics and phylogenetic analysis, the isolate was identified as P. psychrotolerans. The tobacco plants at fast growing stage were selected for pathogenicity tests. Pathogenicity tests were conducted by injecting 10 µL bacterial suspension (108cfu/mL) of ZC5 into tobacco leaves with a syringe. Sterile water was inoculated into the tobacco leaves in the same way as the control. Six plants were selected for pathogenicity tests each time and five leaves of each tobacco plant were inoculated, and the tests were repeated three times. To simulate disease conditions in the natural environment, the inoculated plants were moved outdoors. The average temperature was 32°C during the day and 20°C at night. To maintain humidity, the tobacco leaves were sprayed with water every two days. Symptoms appeared on the pathogen inoculated leaves seven days after inoculation, whereas the control treatment remained symptomless. The pathogens were reisolated from diseased leaves and identified as P. psychrotolerans based on morphological, molecular and phylogenetic analysis, which fulfilled Koch's postulates. To our knowledge, this is the first report of tobacco bacterial leaf spot caused by P. psychrotolerans.

First Report of Leaf Spot Disease caused by Nigrospora oryzae on Nicotiana tabacum in China.

Tobacco (Nicotiana tabacum) is an important economic crop and widely cultivated in rural areas in south of China. A previously uncharacterized disease was observed on field-grown tobacco during 2020 and 2021 around Tongren city, Guizhou province of China (27°59'25.73" N, 108°7'2.43" E). The disease mainly occurred from fast growing period (about 13-16 leaves) to leaf maturity stage. In severely diseased areas, the incidence rate was between 20%-100%. Symptoms first began as yellow-brown necrotic spots on leaves, then merged into larger irregular necrotic spots surrounded by chlorotic halos. Similar lesions were also found on the stems. Ten symptomatic leaf and stem samples were collected from the different infected plants for pathogen isolation. The small pieces of discolored tissues were surface-disinfected with 2% sodium hypochlorite for 3 min and 75% ethanol for 30 s, rinsed three times with sterile water, and blotted on sterile filter paper, placed on potato dextrose agar thenincubated at 28°C in the dark for 3-4 days. The obtained isolates were purified through single-spore culture. Colonies were initially white and fluffy in appearance, later turning gray. Hyphae were smooth, branched, septa, transparent or light brown. Spores were solitary, oblate or nearly spherical, dark brown to black, smooth, 14.3 to 16.1µm × 11.8 to 15.2 µm in diameter. DNA of fungal isolates were extracted using Fungi Genomic DNA Extraction Kit (Solarbio, Beijing, China), the internal transcribed spacer (ITS) of the ribosomal DNA, ß-tubulin (TUB2) gene and translation elongation factor 1-alpha (TEF1-α) were amplified with primers ITS1/ITS4, ßt2a/ßt2b and EF1-1728F/EF1-986R, respectively. The resulting ITS, TUB2 and TEF1-α sequences were deposited at GenBank, NCBI under accessions MZ882151, MZ927749, MZ927747, respectively. The sequence identity of ITS, TUB2 and TEF1-α with those of Nigrospora oryzae strains HBN (KU254608), HGUP191068 (MZ724102) and LC7307 (KY019409) were 99.64%, 99.29% and 99.65%, respectively. Based on morphological features and phylogenetic analysis, the pathogen was identified as N. oryzae (Wang et al. 2017). Pathogenicity tests were conducted by placing agar plugs-containing fungal mycelia and agar blocks (control) on leaves of tobacco plants grown at 28°C with 60% humidity in greenhouse. Symptoms appeared on the pathogen inoculated leaves seven days after inoculation, whereas the control treatment remained symptomless. The pathogens were reisolated from diseased leaves and identified as N. oryzae based on morphological, molecular and phylogenetic analysis, which were fulfilling Koch's postulates. This pathogen was recently identified from watermelon and kiwifruit in the Guizhou (Far and Rossman, 2021). To our knowledge, this is the first report of leaf spot caused by N. oryzae on Nicotiana tabacum in China.

An immunochromatographic test strip for on-site detection of Ralstonia solanacearum in tobacco leaves and soil.

Tobacco bacterial wilt is one of the most devastating soil-borne diseases in tobacco-producing regions worldwide. It is often responsible for significant economic losses during tobacco production. A rapid, specific, and high-throughput on-site detection method is important for plant disease management. In this study, monoclonal antibody 3H3 and polyclonal antibody 0344 specific for Ralstonia solanacearum were used to prepare a colloidal gold-based immunochromatographic test strip (ITS). Under optimal conditions, the detection limit of the ITS was 105 CFU/mL. The ITS was able to detect different R. solanacearum strains collected from Shandong, Yunnan, Guizhou, and Sichuan provinces in China. Moreover, the ITS was highly specific for R. solanacearum, with no cross-reactivity with Alternaria alternata (Fries) Keissler, Pseudomonas syringae pv. angulata, and P. syringae pv. tabaci. Furthermore, R. solanacearum-spiked tobacco leaves and soil were used to evaluate the matrix interference of the developed ITS, which indicated the test strip was unaffected by leaf size or soil abundance.