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In this paper, we present a full coverage path planning (CPP) algorithm for the marine surveys conducted in the convex polygon shaped search area. The survey is supposed to carry out by torpedo-type AUVs (autonomous underwater vehicles). Due to their nonholonomic mechanical characteristics, these vehicles have nonzero minimum turning radius. For any given polygon shaped search area, it can always be partitioned into one or more convex polygons. With this in mind, this paper proposes a novel search algorithm called CbSPSA (Calculation based Shortest Path Search Algorithm) for full coverage of any given convex polygon shaped search area. By aligning the search inter-tracks alongside the edge with the minimum height, we can guarantee the minimum number of the vehicle's turns. In addition, the proposed method can guarantee the planned path is strictly located inside the polygon area without overlapped or crossed path lines, and also has the total path length as short as possible. Considering the vehicle's nonzero minimum turning radius, we also propose a sort of smoothing algorithm which can smooth the waypoint path searched by CbSPSA so that the vehicle can exactly follow it. The smoothed path is also guaranteed to be strictly located inside the polygon. Numerical simulation analyses are also carried out to verify the effectiveness of the proposed schemes. [ABSTRACT FROM AUTHOR]

Gastrochilus is an orchid genus containing about 70 species in tropical and subtropical Asia with high morphological diversity. The phylogenetic relationships among this genus have not been fully resolved, and the plastome evolution has not been investigated either. In this study, five plastomes of Gastrochilus were newly reported, and sixteen plastomes of Gastrochilus were used to conduct comparative and phylogenetic analyses. Our results showed that the Gastrochilus plastomes ranged from 146,183 to 148,666 bp, with a GC content of 36.7–36.9%. There were 120 genes annotated, consisting of 74 protein-coding genes, 38 tRNA genes, and 8 rRNA genes. No contraction and expansion of IR borders, gene rearrangements, or inversions were detected. Additionally, the repeat sequences and codon usage bias of Gastrochilus plastomes were highly conserved. Twenty hypervariable regions were selected as potential DNA barcodes. The phylogenetic relationships within Gastrochilus were well resolved based on the whole plastome, especially among main clades. Furthermore, both molecular and morphological data strongly supported Haraella retrocalla as a member of Gastrochilus (G. retrocallus). [ABSTRACT FROM AUTHOR]

The conversion of CO2 into fuels and valuable chemicals presents a viable path toward carbon neutrality. The aim of this study is to investigate the potential of metal-doped graphene catalysts in the reduction of CO2 to C1 products. 20 typical M-graphene (M = metal) catalysts were established based on DFT calculations. Six candidate catalysts, i.e., V-, Cr-, Mn-, Ni-, Mo-, and Ta-graphene catalysts, were selected by combining the hydrogen dissociation ability and the energy band gap of the catalysts. Subsequently, the adsorption characteristics and hydrogenation reactions of CO2 over the six candidates were explored. CO2 tends to adsorb at the M site through vertical adsorption and carbon–oxygen co-adsorption. V- and Cr-graphene catalysts promote the production of intermediate COOH, whereas Mn-, Ni-, Mo-, and Ta-doped surfaces are more favorable for HCOO formation. Concerning the hydrogenation to CO and HCOOH, V-, Cr-, Ni- and Mo-graphene catalysts preferentially yield CO from COOH, whereas Ta-doped graphene favors the formation of HCOOH. In total, the competitive hydrogenation of CO2 reveals the selectivity of the C1 products. Cr- and Ni-graphene favor the production of HCOOH and CH3OH, whereas V-, Mn-, Mo-, and Ta-graphene primarily yield CH3OH. [ABSTRACT FROM AUTHOR]

Objective To detect the antibody levels of hantavirus in serum samples from patients suspected with hemorrhagic fever with renal syndrome (HFRS) in Heilongjiang Province from 2019 to 2021, and to provide scientific basis for the prevention and control of disease. Methods Enzyme-linked immunosorbent assays (ELISA) were used to detect the IgM antibodies to hantavirus in serum samples collected from suspected patients with HFRS in the acute-phase, and IgM and IgG antibody in convalescent-phase serum samples. The positive rate of IgM antibody in acute-phase serum samples of patients in different years was analyzed with x2 test by SPSS 19.0, and the data were sorted out and analyzed about patients' gender, occupation, age, date of onset and interval from onset to initial diagnosis by EpiData 3.1, Excel 2003 software. Results A total of 351 acute-phase serum samples and 208 convalescent-phase serum samples were detected in patients suspected with HFRS, respectively. There were 317 positive IgM antibodies of serum samples in the acute stage, with the positive rate of 90.31%. There was no significant difference in the positive rate of IgM antibodies in the acute stage between different years (2= 0.895, P=0.639). T The IgM antibodies and IgG antibodies were positive in 32 (15.39%) and 28 (13.46%) of the convalescentphase serum samples, respectively. Moreover, 148 patients (71.15%) were double-positive for IgM and IgG antibodies at the convalescent stage. The ratio of male to female patients was 4.561, for which male patients were much more than female patients. Occupation was dominated by farmers (253 cases, 79.81%), followed by workers (19 cases, 5.99%) and the unemployed (17 cases, 5.36%), respectively. The age of patients ranged from 10 to 88 years old, with a median age of 49 years old. Most of the patients were in the age group from 30 years old to 60 years old (209 cases, 65.93%), among which the age group from 40 years old to 50 years old (86 cases, 27.13%) had the highest proportion, and the age group from 60 years old to 90 years old had a proportion of 20.18% (19 cases). May and November were the peak periods of HFRS in Heilongjiang Province. The median interval between onset and initial diagnosis was 4 days. Conclusions There is a gap of about 10% between the clinical diagnosis of HFRS cases and the confirmed cases detected by laboratory in Heilongjiang Province from 2019 to 2021. The virus-specific detection results are important for confirming the diagnosis of local patients with HFRS. [ABSTRACT FROM AUTHOR]