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The sudden load changes impact power grids by frequency and power oscillations. In order to distinguish the complex and massive abnormal user load data， this paper proposes a method combining multiple features and LOF （local outlier factor） algorithm. Firstly， the statistical characteristic mean value， standard deviation， waveform characteristic dispersion coefficient， kurtosis， waveform factor and pulse factor of load data are extracted， and the effective features are obtained through dimensionality reduction of PCA （principal component analysis）. Furthermore， the LOF algorithm is used to detect abnormal user load data every day. This detection algorithm is used in the Zhejiang power data center based on Alibaba cloud. The results show that it can detect users with abrupt load changes in massive measured data at fixed times of every day and realizes online detection with high accuracy.

Li6PS5Cl (LPSC), a sulfide solid-state electrolyte with an argyrodite structure, is one of the ideal electrolyte materials for the construction of all-solid-state lithium-ion batteries.It has good development prospects because of its high ionic conductivity (>3×10-3 S·cm-1) and good stability to lithium. In this work, LPSC was prepared by the combination of high-energy ball milling and inert atmosphere solid-phase sintering, and powder X-ray diffraction, Raman spectra, and scanning electron microscopy were used to investigate the effects of the preparation process on the structure, composition, electrical properties, and ion conductivity of LPSC. The results show that the extended ball milling time is beneficial to the amorphization and subsequent sintering of the LPSC precursor powder. The increase of the sintering temperature will promote the physical purity and electrical conductivity of the prepared LPSC electrolyte, but the high sintering temperature will lead to the decomposition of LPSC. The LPSC prepared by 8 h ball milling and 500℃ sintering has the highest ion/electron conductivity ratio (2.091×105) at room temperature, with ionic conductivity up to 4.049×10-3 S·cm-1 and electronic conductivity only 1.936×10-8 S·cm-1. The 712 NCM/LPSC/In-Li all-solid-state battery prepared with this electrolyte has a first-turn discharge specific capacity of 151.3 mAh·g-1 at a charge/discharge ratio of 0.1 C, and has excellent cycling stability.

Target threat assessment provides support for combat decision making. The multi-target threat assessment method based on a three-way decision can obtain threat classification while receiving threat ranking, thus avoiding the limitation of traditional two-way decisions. However, the heterogeneous situation information, attribute relevance, and adaptive information processing needs in complex battlefield environment bring challenges to existing methods. Therefore, this paper proposes a new multi-target three-way threat assessment method with heterogeneous information and attribute relevance. Firstly, dynamic assessment information is represented by heterogeneous information, and attribute weights are calculated by heterogeneous Criteria Importance Through Intercriteria Correlation (CRITIC). Then, the conditional probability is calculated by the heterogeneous weighted Technique for Order Preference by Similarity to Ideal Solution (TOPSIS), and the adaptive risk avoidance coefficients are constructed by calculating the uncertainty of the assessment value, and then the relative loss function matrices are constructed. Finally, the comprehensive loss function matrices are obtained by the weighted Heronian mean (HM) operator, and the comprehensive thresholds are calculated to obtain the three-way rules. The case study shows that compared with the existing methods, the proposed method can effectively handle the heterogeneous information and attribute relevance, and obtain the risk avoidance coefficients without presetting or field subjective settings, which is more suitable for the complex mission environment. [ABSTRACT FROM AUTHOR]

Intelligent vehicular networks can not only connect various smart terminals to manned or unmanned vehicles but also to roads and people's hands. In order to support diverse vehicle-to-everything (V2X) applications in dynamic, intelligent vehicular networks, efficient and flexible routing is fundamental but challenging. Aimed to eliminate routing voids in traditional Euclidean geographic greedy routing strategies, we propose a hyperbolic-embedding-aided geographic routing strategy (HGR) in this paper. By embedding the network topology into a two-dimensional Poincaré hyperbolic disk, greedy forwarding is performed according to nodes' hyperbolic coordinates. Simulation results demonstrated that the proposed HGR strategy can greatly enhance the routing success rate through a smaller stretch of the routing paths, with little sacrifice of routing computation time. [ABSTRACT FROM AUTHOR]

Traditional multicast routing strategies can hardly meet the demanding requirements of multicasting mission assignment messages in airborne tactical networks. This letter proposes an intent‐driven routing strategy, termed as IDR, to realize reliable and efficient multicast. IDR exploits bit index explicit replication technique to encode not only the destination information but also the retransmission information into packet headers. If part of the multicast members failed to receive the packet, IDR can perceive the error and retransmit the packet to the precise set of nodes. Compared to the state‐of‐the‐art reliable multicast routing methods, IDR can enhance multicast retransmission success rate by about 10% or more and reduce retransmission overhead by around 50%. [ABSTRACT FROM AUTHOR]

Background: Stigma toward mental disorders (STMD) is a significant barrier to mental health service delivery. To improve the provision of mental health services for community‐dwelling residents in China, this study investigated STMD and its associated factors in community mental health workers (CMHWs) in Wuhan, China. Methods: In this cross‐sectional study, a total of 3869 CMHWs (22.9% men and 37.1 ± 8.4 years old) were randomly selected through multistage sampling and invited to participate in this survey. The perceived devaluation‐discrimination scale (PDD) and the National Mental Health Literacy Questionnaire (NMHLQ) were used to assess STMD and mental health knowledge, respectively. The presence of STMD was indicated by a mean item score of 3.0 or higher on the PDD. Multiple logistic regression was used to identify factors associated with STMD. Results: Of the CMHWs, 41.9% had poor mental health knowledge (NMHLQ score < 80), and 18.5% exhibited STMD. In multiple regression analysis, factors significantly associated with STMD were social workers (vs. primary care physicians, OR = 1.44, p <.001), poor self‐rated capacity to handle common mental health problems (vs. good, OR = 1.57, p <.001), and poor mental health knowledge (vs. NMHLQ score ≥ 80, OR = 1.46, p <.001). Conclusion: STMD is common among Chinese CMHWs. To reduce STMD among CMHWs, training programs in mental health care skills and mental health education may be necessary. [ABSTRACT FROM AUTHOR]

Lung adenocarcinoma (LADC) is a prevalent type of lung cancer that is associated with lung and gut microbiota. However, the interactions between these microbiota and cancer development remain unclear. In this study, a microbiome study was performed on paired fecal and bronchoalveolar lavage fluid (BALF) samples from 42 patients with LADC and 64 healthy controls using 16S rRNA gene amplicon and shotgun metagenome sequencing, aiming to correlate the lung and gut microbiota with LADC. Patients with LADC had reduced α-diversity in the gut microbiome and altered β-diversity compared with healthy controls, and the abundances of Flavonifractor, Eggerthella, and Clostridium were higher in the gut microbiome of LADC patients. The increased abundance of microbial species, such as Flavonifractor plautii, was associated with advanced-stage LADC and a higher metastasis rate. Phylogenetically, Haemophilus parainfluenzae was the most frequently shared taxon in the lung and gut microbiota of LADC patients. Gut microbiome functional pathways involving leucine, propanoate, and fatty acids were associated with LADC progression. In conclusion, the low diversity of the gut microbiota and the presence of H. parainfluenzae in gut and lung microbiota were linked to LADC development, while an increased abundance of F. plautii and the enriched metabolic pathways could be associated with the progression of LADC. [ABSTRACT FROM AUTHOR]

Salmonella enterica is one of the most common bacterial pathogens in humans and animals. Systematic studies on the trends and geographical distribution of antimicrobial-resistant Salmonella and dominant serovars have been well studied in European and American countries while not in China. Here, taking the One-Health strategy, we used >35 000  Salmonella enterica isolates to explore the temporal and spatial dynamics of dominant serovars in China. We found that Salmonella Typhimurium was the dominant serovar causing human infection in China, which was consistent with Australia but inconsistent with North American and European countries. The proportion of Salmonella serovars Typhimurium, London, Rissen, Corvallis, Meleagridis, Kentucky, and Goldcoast showed an increasing trend during 2006–2019. We randomly selected 1962 isolates for comparative genomics and antimicrobial resistance studies and found that the number of antibiotic resistance genes (ARGs) per isolate increased 1.84 and 2.69 times of human and non-human origins, respectively, spanning 14 years. The proportion of antimicrobial-resistant Salmonella isolates had an increasing trend during 2006–2019, especially beta-lactam, quinolone, tetracycline, and rifampicin resistance. Moreover, we found that higher diversity of sequence types (STs) in S. Typhimurium than in other serovars, ST34 from pig and ST19 from chicken origin, were mainly associated with isolates causing child and adult gastro-infection, respectively. Our results fill in the data gap on the trends of dominant serovars and antimicrobial resistance of Salmonella enterica in China. These data provide useful information for public health decision-makers prioritizing interventions for foodborne diseases and food safety. [ABSTRACT FROM AUTHOR]

Wireless network virtualization is widely used to solve the ossification problem of networks, such as 5G and the Internet of Things. The most crucial method of wireless network virtualization is virtual network embedding, which allows virtual networks to share the substrate network resources. However, in wireless networks, link interference is an inherent problem while mapping virtual networks because of the characteristics of wireless channels. To distribute resources efficiently and address the problem of interference, a dynamic embedding algorithm with deep reinforcement learning is proposed. During the training stage, we take resource use and interference from substrate networks as observations to train the agent, and then the agent generates a resource allocation strategy. Aiming at realizing load balance, we reshape the reward function considering the execution ratio and residual ratio of substrate network resources as well as the cost consumed by current virtual network request. Numerical tests show that our embedding approach increases the acceptance ratio and maintains better robustness. Moreover, the results also illustrate that our algorithm maintains a high acceptance ratio while producing less interference and lower cost. [ABSTRACT FROM AUTHOR]

During the rolling process of profile ring, the design of the rolling cavity directly affects the forming quality of the final ring. In order to improve the cavity filling rate and reduce the production cycle time, this paper proposes a general evaluation method of the filling difficulty for profile ring rolling cavity by combining the response surface method(RSM) and the finite element method(FEM) with the step-type ring as the research object. Firstly, a universally applicable design method for profile ring rolling cavity is proposed, and based on the description of the rolling cavity, three design variables and a corresponding response objective are defined to achieve multi-objective optimization. Secondly, a finite element model of this step-type ring rolling process is established, and the response model is built and improved by significance analysis and analysis of variance(ANOVA) based on the forming simulation results. Then, the effects of different variables on the optimization objectives are comprehensively investigated by this response model. Finally, the evaluation method of the filling difficulty for profile ring rolling cavity is obtained by combining the contour plot of the response objective.

In view of the problem that the current asynchronous network update method takes a long time to update and can not avoid updating deadlock, in order to reduce the network performance loss during updating, a time-based update method for airborne network of aviation swarm is proposed. Considering the real link delay, the time parameter is combined with the update dependency graph. Firstly, a time-based update dependency graph is constructed. Secondly, a greedy scheduling algorithm is designed to allocate the update time step for each update operation. Finally, the timed network update is realized and the update sequence coordination in asynchronous update is avoided. Simulation experiments show that compared with the existing asynchronous updating methods, the update time can be reduced by 50%~60% through the proposed timing update method, and the update deadlock rate and the network congestion are reduced during the network update. [ABSTRACT FROM AUTHOR]

Salmonella enterica remains one of the leading causes of foodborne bacterial disease. Retail meat is a major source of human salmonellosis. However, comparative genomic analyses of S. enterica isolates from retail meat from different sources in China are lacking. A total of 341 S. enterica strains were isolated from retail meat in sixteen districts of Beijing, China, at three different time points (January 1st, May 1st, and October 1st) in 2017. Comparative genomics was performed to investigate the genetic diversity, virulence and antimicrobial resistance gene (ARG) profiles of these isolates. The most common serotype was S. Enteritidis (203/341, 59.5%), which dominated among isolates from three different time points during the year. Laboratory retesting confirmed the accuracy of the serotyping results predicted by the Salmonella In Silico Typing Resource (SISTR) (96.5%). The pangenome of the 341 S. enterica isolates contained 13,931 genes, and the core genome contained 3,635 genes. Higher Salmonella phage 118970 sal3 (219/341, 64.2%) and Gifsy-2 (206/341, 60.4%) prevalence contributed to the diversity of the accessory genes, especially those with unknown functions. IncFII(S), IncX1, and IncFIB(S) plasmid replicons were more common in these isolates and were major sources of horizontally acquired foreign genes. The virulence gene profile showed fewer virulence genes associated with type III secretion systems in certain isolates from chicken. A total of 88 different ARGs were found in the 341 isolates. Three beta-lactamases, namely, bla CTX – M –55 (n = 15), bla CTX – M –14 (n = 11), and bla CTX – M –65 (n = 11), were more prevalent in retail meats. The emergence of qnrE1 and bla CTX – M –123 indicated a potential increase in the prevalence of retail meats. After the prohibition of colistin in China, three and four isolates were positive for the colistin resistance genes mcr-1.1 and mcr-9 , respectively. Thus, we explored the evolution and genomic features of S. enterica isolates from retail meats in Beijing, China. The diverse ARGs of these isolates compromise food security and are a clinical threat. [ABSTRACT FROM AUTHOR]

• The first clinical isolate of mcr-3.1-positive MDR Salmonella Choleraesuis. • Complete sequence of a transferable plasmid with mcr-3.1 contained in a prophage. • Plasmid pXXB210 contained resistance genes for six classes of antimicrobials. [ABSTRACT FROM AUTHOR]

To solve the problem of control node failure in the control domain of software-defined airborne network of the aviation swarm, the problem of failure recovery is transformed into the issue of leader election, and an election-based software-defined airborne network controller failure recovery mechanism is proposed, and the transmission node is elected as a new control one in the control domain. To optimize the performance of the new control node, the three parameters of the average transmission delay, the maximum request amount and the average failure rate of each transmission node are combined to calculate the weight of the transmission node. The election priority is defined according to the weight, and a priority-based control node election (PBCNE) algorithm is proposed. The experimental results show that compared with the existing election algorithms, the complexity (number of messages and amount of time) of the PBCNE algorithm has been significantly reduced, the failure recovery delay has been effectively reduced, and the controller failure can be recovered quickly and efficiently. [ABSTRACT FROM AUTHOR]

This study was conducted to explore the composition of the fecal microflora of Chinese Parkinson's disease (PD) patients, as well as to explore links between PD clinical features and antiparkinsonian medications on the gut microflora. Seventy-two PD cases [59 patients suffering from PD for >1 year (OPD) and 13 new PD (NPD) patients] were studied. Microflora communities in the feces of the patients and corresponding healthy controls (HCs) were examined using high-throughput Illumina MiSeq sequencing targeting the 16S rRNA gene. The gut microflora of OPD patients contained high levels of Rikenellaceae compared to corresponding HCs. In addition, significantly higher levels of Turicibacteraceae were found in the NPD group compared to the corresponding HCs. The genera Turicibacter and Prevotella were significantly correlated with the PD severity scores. Our findings that some fecal microflora were closely related to PD clinical characteristics may enhance our understanding of the pathogenesis and treatment of PD. [ABSTRACT FROM AUTHOR]

The aim of this paper is to provide a review of the clinical features and treatment of comorbid bipolar disorder and obsessive-compulsive disorder， and to provide evidence for early identification and appropriate intervention. The clinical phenomenon of comorbid bipolar disorder and obsessive-compulsive disorder is hardly unusual， while the treatment strategies of the two kinds of diseases are different or even mutually exclusive， thus leading to the treatment dilemma. Based on this， the paper will discuss the research progress on the epidemiology， clinical features and treatment of comorbid bipolar disorder and obsessive-compulsive disorder.

Composition of the gut microbiota has been linked with human immunedeficiency virus (HIV)-infected patients on antiretroviral therapy (ART). Evidence suggests that ART-treated patients with poor CD4+ T-cell recovery have higher levels of microbial translocation and immune activation. However, the association of the gut microbiota and immune recovery remains unclear. We performed a cross-sectional study on 30 healthy controls (HC) and 61 HIV-infected individuals, including 15 immunological ART responders (IRs), 20 immunological ART non-responders (INRs) and 26 untreated individuals (VU). IR and INR groups were classified by CD4+ T-cell counts of ≥350 cells/mm3 and <350 cells/mm3 after 2 years of ART, respectively. Each subject’s gut microbiota composition was analyzed by metagenomics sequencing. Levels of CD4+ T cells, CD8+HLA-DR+ T cells and CD8+CD38+ T cells were measured by flow cytometry. We identified more Prevotella and fewer Bacteroides in HIV-infected individuals than in HC. Patients in INR group were enriched with Faecalibacterium prausnitzii, unclassified Subdoligranulum sp. and Coprococcus comes when compared with those in IR group. F. prausnitzii and unclassified Subdoligranulum sp. were overrepresented in individuals in VU group with CD4+ T-cell counts <350 cells/mm3. Moreover, we found that the relative abundance of unclassified Subdoligranulum sp. and C. comes were positively correlated with CD8+HLA-DR+ T-cell count and CD8+HLA-DR+/CD8+ percentage. Our study has shown that gut microbiota changes were associated with CD4+ T-cell counts and immune activation in HIV-infected subjects. Interventions to reverse gut dysbiosis and inhibit immune activation could be a new strategy for improving immune reconstitution of HIV-1-infected individuals. [ABSTRACT FROM AUTHOR]

Objectives: As current clinical practice guidelines, ticagrelor is the suggested therapeutic scheme to prevent adverse cardiovascular events in acute myocardial infarction (AMI) patients undergoing percutaneous coronary intervention (PCI) treatment. However, this therapeutic strategy still fails, and around 30% patients display inadequate antiplatelet responses. Musk Tongxin Dripping Pill (MTDP) in Chinese hospital was usually considered as the combination with ticagrelor to improve the treatment effect. Unfortunately, the mechanism has not been elucidated.Methods: The untargeted metabolomic method was introduced based on liquid chromatography–high-resolution mass spectrometry (HPLC-HRMS) coupled with STI for the research of the drug combination mechanism between ticagrelor and MTDP. 28 patients with a confirmed diagnosis of AMI were selectively collected, who were then divided into two different dosage regimen groups, and the serum samples were collected for the untargeted metabolomics assay. Then the differential metabolites were associated with blood biochemical indicators.Results: The GLS values in both groups increased after treatment and those in the ticagrelor and MTDP combination group after treatment were higher than those in the ticagrelor group (p < 0.05), suggesting that the combination medication has better therapeutic effect on patients with myocardial infarction. From metabolomics analysis, the species of metabolites changed in two groups before and after treatment. Moreover, 93 differential metabolites changed in the drug combination group compared with the ticagrelor group after treatment (p < 0.05), which mainly related to changes in fatty acid metabolism pathways. Then the differential metabolites were found to be related with blood biochemical indicators, such as lipid, high-density lipoprotein (HDL), and low-density lipoprotein (LDL).Conclusion: This work will provide a possible mechanism of the drug combination interaction between ticagrelor and MTDP from two angles of echocardiography and metabonomics. Several potential metabolic pathways were also found to have a relationship with MTDP, which will provide a new perspective in clinical medication.

Patterns of clonal growth in natural populations of two Sagittaria species ( Sagittaria trifolia and Sagittaria pygmaea ) were studied based on allozyme data, and spatial autocorrelation analysis was employed to assess their clonal structures. Ramets per multilocus genotypes in the studied populations varied from 1.556 to 5.468, and showed distinct features in clonal intensity between the two species. High clonal diversity was found in both species, with Simpson’s diversity index ranging from 0.817 to 0.968 in the studied populations. Moran’s I indices of multilocus genotypes in the studied populations, calculated by means of a Gabriel map, were higher than expected, which indicates that the spatial autocorrelation of clones was positive in each population. Comparatively, the value of Moran’s I ( I = 0.210∼0.354) for the S. pygmaea population was higher than that for the S. trifolia population. The change in Moran’s I with different distance classes in each population revealed differences in the features of clonal dispersal in the two species: the ramets of each clone preferably distributed in a limited area in populations of S. pygmaea , whereas there was the potential for long-distance spread for the ramets of S. trifolia . The authors deduced that the spatial autocorrelation of multilocus genotypes should be directly related to the clonal growth modes of the species. [ABSTRACT FROM AUTHOR]

To give full play to the circulation function of the port container logistics park, it is urgent to study the development intensity of the land in the port container logistics park and to guide the scientific development of the port logistics park with reasonable development intensity control index. The current situation of land development intensity control index of container logistics park at home and abroad is analysed, the PENT (politics, economy, society and technology) analysis method is used to analyse the factors influencing the land development intensity control index of container logistics park, and the index system structure of influencing factors is constructed. Finally, index value is obtained quantitatively with the proposed calculation method of the land development intensity index of the port container logistics park. Its practicability is verified in case analysis.

A field experiment was conducted for two years to investigate the effects of different fertilization applications on the suppression of banana fusarium wilt disease , crop yield , fruit quality and culturable microflora in a banana orchard which has been monocultured with banana for 12 years and suffered serious banana fusarium wilt disease. The fertilizers included chemical fertilizer (CF) , cow manure compost (CM) , pig manure compost (PM) and bio-organic fertilizer (RIO). The banana soil microflora was invested using plate-counting method and culture-dependent polymerase chain reaction denaturing gradient gel electrophoresis method ( CD PCR-DGGE). Results showed that, compared with the other treatments, 2-year consecutive application of RIO significantly reduced the banana fusarium wilt disease incidence, and improved the banana mass per tree, crop yield, total soluble sugar content and the ratio of total soluble sugar to titratable acidity of fruits (sugar/acid ratio). Moreover, the analysis of culturable microflora showed that RIO application significantly increased the soil microbial biomass, soil culturable bacteria, bacillus and actinomycetes, and the ratio of bacteria to fungi (R/F) , while decreased the Fusarium oxysporum. Rased on the CD PCR-DGGE results, the RIO application significantly altered the soil culturable bacterial structure and showed highest richness and diversity after 2 years of RIO application. The phylogenetic analysis of the selected hands showed that BIO application enriched the soil with the species of Paenibacillus sp., Burkholderia sp., uncultured Verrucomicrobia sp. and Bacillus aryabhattai, and depressed the species of Ralstonia sp. , Chryseobacterium gleum, Fluviicola taffensis , Enterobacter sp. and Bacillus megaterium. These results confirmed that the continuous application of BIO effectively controlled the fusarium wilt disease, improved the crop yield and fruit quality, and modulated the soil culturable microflora under field condition. [ABSTRACT FROM AUTHOR]

• More diversified ARGs were identified the LPMs than the farms. • The live poultry trade may speed up the spread of antibiotic resistance. • LPM workers are exposed to antimicrobial resistant bacteria in LPMs. • More abundant ARGs were observed in the LPM workers than control subjects. • The prevalence of mcr-1 decreased significantly in LPMs after the ban on colistin as a growth promoter. Poultry farms and LPMs are a reservoir of antimicrobial resistant bacteria and resistance genes from feces. The LPM is an important interface between humans, farm animals, and environments in a typical urban environment, and it is considered a reservoir for ARGs and viruses. However, the antibiotic resistomes shared between chicken farms and LPMs, and that of LPM workers and people who have no contact with the LPMs remains unknown. We characterized the resistome and bacterial microbiome of farm chickens and LPMs and LPM workers and control subjects. The mobile ARGs identified in chickens and the distribution of the mcr -family genes in publicly bacterial genomes and chicken gut metagenomes was analyzed, respectively. In addition, the prevalence of mcr-1 in LPMs following the ban on colistin-positive additives in China was explored. By profiling the microbiomes and resistomes in chicken farms, LPMs, LPM workers, and LPM environments, we found that the bacterial community composition and resistomes were significantly different between the farms and the LPMs, and the LPM samples possessed more diversified ARGs (59 types) than the farms. Some mobile ARGs, such as mcr-1 and tet (X3), identified in chicken farms, LPMs, LPM workers, and LPM environments were also harbored by human clinical pathogens. Moreover, we found that the resistomes were significantly different between the LPM workers and those who have no contact with the LPMs, and more diversified ARGs (188 types) were observed in the LPM workers. It is also worth noting that mcr-10 was identified in both human (5.2%, 96/1,859) and chicken (1.5%, 14/910) gut microbiomes. Although mcr-1 prevalence decreased significantly in the LPMs across the eight provinces in China, from 190/333 (57.1%) samples in September 2016-March 2017 to 208/544 (38.2%) samples in August 2018-May 2019, it is widespread and continuous in the LPMs. Live poultry trade has a significant effect on the diversity of ARGs in LPM workers, chickens, and environments in China, driven by human selection with the live poultry trade. Our findings highlight the live poultry trade as ARG disseminators into LPMs, which serve as an interface of LPM environments even LPM workers, and that could urge Government to have better control of LPMs in China. Further studies on the factors that promote antibiotic resistance exchange between LPM environments, human commensals, and pathogens, are warranted. [ABSTRACT FROM AUTHOR]

Abstract Background To search for chemical structures in research articles, diagrams or text representing molecules need to be translated to a standard chemical file format compatible with cheminformatic search engines. Nevertheless, chemical information contained in research articles is often referenced as analog diagrams of chemical structures embedded in digital raster images. To automate analog-to-digital conversion of chemical structure diagrams in scientific research articles, several software systems have been developed. But their algorithmic performance and utility in cheminformatic research have not been investigated. Results This paper aims to provide critical reviews for these systems and also report our recent development of ChemReader – a fully automated tool for extracting chemical structure diagrams in research articles and converting them into standard, searchable chemical file formats. Basic algorithms for recognizing lines and letters representing bonds and atoms in chemical structure diagrams can be independently run in sequence from a graphical user interface-and the algorithm parameters can be readily changed-to facilitate additional development specifically tailored to a chemical database annotation scheme. Compared with existing software programs such as OSRA, Kekule, and CLiDE, our results indicate that ChemReader outperforms other software systems on several sets of sample images from diverse sources in terms of the rate of correct outputs and the accuracy on extracting molecular substructure patterns. Conclusion The availability of ChemReader as a cheminformatic tool for extracting chemical structure information from digital raster images allows research and development groups to enrich their chemical structure databases by annotating the entries with published research articles. Based on its stable performance and high accuracy, ChemReader may be sufficiently accurate for annotating the chemical database with links to scientific research articles.