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Objective: To improve the accuracy of the results of cadmium （Cd） content in kelp （Laminaria japonica） by graphite furnace atomic absorption spectrometry （GF-AAS）. Methods: The concentration of Cd element in kelp sample was measured by using GF-AAS after microwave digestion according to the standard of GB 5009.15—2014. Combining with the experimental process and mathematical model, the possible sources of measurement uncertainty were firstly identified, then the components of each standard uncertainties were calculated, and finally each parameter of uncertainties was synthesized, and the whole uncertainty was evaluated. Results: when the value of Cd concentration in kelp was 0.202 mg/kg, the expanded uncertainty was 0.008 mg/kg （k=2）. Conclusion: The uncertainty of the method is mainly derived from the determination of Cd concentration in the sample solution, which is basically introduced by standard working solution preparation. Moreover, the uncertainty caused by the sample recovery rate is also large. So the quality control of the parameter of uncertainties should be strengthened in the future.

Aeromonas veronii JY01 is a strain of dominant gram-negative bacterium isolated from the lesions of goldfish, such as rotten tails, rot, and ulcers in a farm in Fuzhou. In this study, the whole genome of the strain of Aeromonas veronii JY01 was sequenced based on the Illumina PE150 sequencing platform and Pacbio sequencing platform. The sequencing data was assembled and analyzed, the gene prediction and functional annotation were performed by bioinformatics methods, meanwhile the prediction of pathogenic genes and drug resistance genes were carried out. The results showed that the genomic sequence length of the strain of Aeromonas veronii JY01 was 4. 97 Mb, and the GC content was 58. 17%. A total of 4 601 encoding genes, 31 rRNA, 16 gene islands and 124 tRNA were predicted, among which, 3 461 genes were annotated in COG, 3 082 genes were aggregated in GO cluster analysis, and 4 345 genes were enriched in KEGG metabolic pathway. It was predicted that the strain of Aeromonas veronii JY01 carried 13 virulence factors including 240 related virulence genes, and 9 types of antibiotics resistance including 175 antibiotic resistance genes. [ABSTRACT FROM AUTHOR]

Decomposing the output signal of fiber optical current transformer (FOCT) with time-frequency conversion is the key step to obtain the gradual fault characteristics. Aiming at the characteristics of FOCT gradual fault signal with large time domain span and random deterioration process,the output signal is sampled across intervals,and the wavelet packet decomposition algorithm is used to extract fault signal features according to the frequency band of the fault signal. The characteristic parameters are screened to obtain the optimal characteristic parameters that characterize the FOCT degradation trend.The principal component analysis method is proposed to reduce the dimensionality of high-dimensional features,the problem of high signal feature dimensionality is solved,and the need for fast fault feature identification is met. Experiment results show that the wavelet algorithm can decompose the signal into various frequency bands and obtain 64 sub-sequences containing signals of different frequency bands. The operating status of the transformer is determined by the energy ratio of each frequency band of the wavelet signal,and the gradual fault identification is realized.

The construction of nanocrystals with controllable composition and desirable micro-nanostructures is a well-known challenge. A combination of favorable composition and optimized micro-nanostructures can enhance the performance of a material significantly. Using TiO2 as an example, we demonstrate here a facile approach to prepare anatase/rutile mixed-phase TiO2 hollow micro-nanospheres with hierarchical mesopores. Our strategy relies on polymer-assisted assembly of [?] 5 nm nano-building blocks into three-dimensional hierarchical hollow micro-nanospheres in a mixed alcohol-water solution. This superior micro-nanostructure endows the sample with hierarchical mesopores and a high surface area of 106 m2 g [?] 1. We also show that, due to the synergetic effects of the mixed-phase composition and the micro-nanostructures, the sample exhibited significantly improved photovoltaic performance and similar photocatalytic performance compared with the commercial Degussa P25. These results suggested that our sample has great potential for future photovoltaic and photocatalytic applications. [ABSTRACT FROM AUTHOR]

Pineapple (Ananas comosus) is a perennial economically important tropical fruit in Guangxi Province, China. Between September to November 2022, the rot of heart leaves of pineapple was found on 6.7 hectares of pineapple, NaLang village Jiangxi Town, Jiangnan District, Nanning City and on 200 hectare Liutian Village, Wangmao Town, Bobai County, Yulin City. The disease incidence of the investigated 10500 plants was from 20% to 30%. The basal heart leaves near the soil surface showed symptoms of water-soaked lesions and soft rot. The infected heart leaves were easily pulled out. As the disease developed, 800 plants of the investigated diseased plants collapsed and died. The diseased leaves from each district were surface-disinfected for 3 min with 1.0% hypochlorite solution, then rinsed three times in sterile water, and plated to carrot agar medium (CA media) (Luo et al. 2012). Inoculated dishes were incubated at 28°C in the dark. After 5 days, Eight mycelium colonies were recovered from diseased tissue. Colonies developing on CA exhibited white cottony mycelium which was aseptate. Numerous sporangia and chlamydospores were visible after 10-15 d later. The chlamydospores were spherical in shape and measured an average of 25.8 to 37.5 μm. The shape of the sporangia was papillate, oval or spherical, and 34.5 to 58.2 μm. These characteristics were consistent with the description of Phytophthora (Stamps et al. 1990). For molecular identification, the direct colony PCR method (Lu et al. 2012) was used to amplify the ITS of rDNA, β-tubulin (Tu), and elongation factor (EF) locus of the 2 strains NNPN1 from Nanning city and YLPN1 from Yulin city using the primer pairs of ITS4/ITS5, T1/T2 (O'Donnell et al. 1997) and EF1/EF2 (O'Donnell et al. 1998). The resulting sequences were deposited in GenBank (OR612028 and OR612029 for ITS; OR620158 and OR620159 for elongation factor; OR620160 and OR620161 for β-tubulin). BLAST searches with the three gene sequences revealed the greatest similarity with the sequences of some Phytophthora sp. The complete genome sequences of highly similar Phytophthora sp. were downloaded and the sequences of the corresponding 3 genes of each genome was extracted by Bioedit software. Phylogenetic trees were constructed in MEGA 11 using the maximum likelihood (ML) method based on the concatenated sequences of ITS, EF1α, and Tubulin (Figure 1). The 2 isolates grouped with P. nicotianae in the phylogenetic tree. The morphology and multi-gene phylogenetic analysis indicated that the new isolate was P. nicotianae. Tests of pathogenicity were performed according to Koch's postulates using the P. nicotianae strains NNPN1 and YLPN1. Fresh wounds were made symmetrically with a sterile needle on 2 tender basal leaves of pineapple plants (Bali variety) at the 8- to 10-leaf stage and each wound was covered with a piece of mycelium disc from each isolate. Control seedlings were inoculated identically except CA medium disc was used to cover the wound. Plants were placed in pots in a greenhouse at 28°C and 90% relative humidity. After 12 days, soft rot was observed clearly on the base of heart leaves of 9 inoculated plants, while the 9 control plants appeared normal. The pathogenicity tests were conducted three times with similar results. The strains were then reisolated from the infected plants and found to be Phytophthora sp. as those of the inoculum by morphology. P. nicotianae was previously reported as the causal agent of heart rot of pineapple in Guangdong and Hainan Province of China (Luo et al. 2012; Shen et al. 2013). To our knowledge, this is the first report of P. nicotianae on pineapple in Guangxi province in China. Identification of the pathogen of heart rot disease on pineapple is vital to reduce yield losses of the disease using effective control method.

Yam is the world's fourth most important tuber crop, after cassava, potato, and sweet potato in the world, the cultivation area of yam from the Food and Agriculture Organization of the United Nations Statistics Division database (FAOSTAT) is about 8,831,037 ha in 2020. Chinese yam (Dioscorea opposita Thunb.) is an economically important root crop throughout China due to its high economic and medicinal value. South China including Guangdong and Guangxi provinces is one of the important production districts of Chinese yam with economic value. A disease affecting the leaves was observed on yam leaves in August 2021 with an incidence of 20 to 90% in Guangdong and Guangxi provinces. Symptoms start as pinpoint lesions on yam leaves which enlarged to oval spots and large irregular spots. The spots were brown and surrounded by a chlorotic halo with sunken cavities, which are typical symptoms of anthracnose. To identify the causal agent, 9 symptomatic leaves from 3 different districts were collected in Guangdong and Guangxi provinces. Leaf samples were disinfested with 1% NaOCl for 3 min, and cultured on potato dextrose agar (PDA) at 28 °C for 3 days week. 9 single-spore isolates were recovered from each PDA medium. Colonies on PDA were grayish white with bright orange conidial spore masses. Fungal mycelia were hyaline, septate, and branched. Conidia were born on a long conidiogenous cell, straight, hyaline and cylindrical with rounded ends, 5.3 to 6.8×15.2 to 21.3μm (n = 50). Appressoria were dark, smooth-walled, oval in shape. The isolates were morphologically identified as Colletotrichum sp. (Weir et al. 2012). 3 strains were used for the pathogenicity test, 5 plants at creeping stage were inoculated with each isolate separately and 3-5 leaves of each plant were inoculated. Fresh wounds were made with a sterile needle on the healthy surface of yam leaves and each leaf was covered with a piece of cotton drenched with conidial suspension (106 conidia/mL) from each isolate. Control seedlings were inoculated identically except sterile water was used. Inoculated plants were placed in a moisturizing light incubator at 25℃ and 80% humidity under a 12-h light/dark cycle for 7 days and examined daily to monitor disease symptom development. Small round brown spots were observed at the inoculation sites 3 days after the inoculation and eventually became large brown lesions. No symptoms wre observed in the water-inoculated plants. A Colletotrichum sp. strain based on morphology was reisolated from inoculated leaves, fulfilling Koch's postulates. For molecular identification, the direct colony PCR method (Lu et al. 2012) was used to amplify the internal transcribed spacer (ITS) region of ribosomal DNA, calmodulin (Cal), tubulin (Tub) and Apmat loci of three isolates using primer pairs of ITS4/ITS5, CL1C/CL2C, T1/T2 and AM-F/AM-R (Sharma et al. 2015). A phylogenetic tree derived from a maximum likelihood analysis of a concatenated alignment of ITS, Cal, Tub and ApMAT sequences was created. The accession numbers of the three isolates YamZJCS, YamSXCS and YamYLCS used in this study were OP128056-OP128058 for ITS, OP128059-OP128061 for ApMAT，OP128062-OP128064 for Cal and OP128065-OP128067 for Tub. The sequences of the 3 isolates were aligned with related species of Colletotrichum (Sharma et al. 2015). Analyses based on concatenated data sets of 4 genes showed that the sequences had high levels of identity to that of the C. siamense strains. According to both morphological and sequence analyses, the pathogen was identified as C. siamense. There were reports of anthracnose on yam caused by Colletotrichum sp. in Guangxi (Zhu et al. 2007), Hainan (Lin et al. 2018) and Jiangsu (Han et al. 2020) provinces in China. To our knowledge, this is the first report of anthracnose on D. opposita caused by C. siamense in Guangdong province in China.