Reversible solvent interactions with UiO-67 metal-organic frameworks.

The utility of UiO-67 Metal-Organic Frameworks (MOFs) for practical applications requires a comprehensive understanding of intermolecular host-guest MOF-analyte interactions. To investigate intermolecular interactions between UiO-67 MOFs and complex molecules, it is useful to evaluate the interactions with simple polar and non-polar analytes. This problem is approached by investigating the interactions of polar (acetone and isopropanol) and non-polar (n-heptane) molecules with functionalized UiO-67 MOFs via temperature programmed desorption mass spectrometry and temperature programmed Fourier transform infrared spectroscopy. We find that isopropanol, acetone, and n-heptane bind reversibly and non-destructively to UiO-67 MOFs, where MOF and analyte functionality influence relative binding strengths (n-heptane ≈ isopropanol > acetone). During heating, all three analytes diffuse into the internal pore environment and directly interact with the µ3-OH groups located within the tetrahedral pores, evidenced by the IR response of ν(µ3-OH). We observe nonlinear changes in the infrared cross sections of the ν(CH) modes of acetone, isopropanol, and n-heptane following diffusion into UiO-67. Similarly, acetone's ν(C=O) infrared cross section increases dramatically when diffused into UiO-67. Ultimately, this in situ investigation provides insights into how individual molecular functional groups interact with UiO MOFs and enables a foundation where MOF interactions with complex molecular systems can be evaluated.

Microplastics Enhance the Prevalence of Antibiotic Resistance Genes in Anaerobic Sludge Digestion by Enriching Antibiotic-Resistant Bacteria in Surface Biofilm and Facilitating the Vertical and Horizontal Gene Transfer.

Antibiotic resistance genes (ARGs) and microplastics (MPs) are recognized as emerging contaminants and threats to global human health. Despite both of them being significantly detected in their "hotspots", i.e., waste activated sludge (WAS), rare studies on how MPs affect ARGs and antibiotic-resistant bacteria (ARB) in anaerobic sludge digestion are available. Herein, the fate of ARGs and ARB after exposure to MPs of three dosages (10, 30, and 80 particles/g-TS), three polymer types (LDPE, PET, and PS), and three branching extents (LDPE, LLDPE, and HDPE) in anaerobic sludge digestion was investigated. Metagenomic results indicated that all variants of MPs resulted in an increase of the relative abundance of ARGs in the digester compared to the control. The abundance of ARGs demonstrated a dosage-dependent relationship within the range from 10 to 80 particles/g-TS, resulting in an increase from 4.5 to 27.9% compared to the control. Branching structure and polymer type influence ARG level in the sludge digester as well. Mechanism studies revealed that LDPE selectively enriched potential ARB and ARGs in the surface biofilm, possibly creating a favorable environment for ARB proliferation and ARG exchange. Furthermore, vertical transfer of ARGs was facilitated by LDPE through increasing bacterial cell proliferation accompanied by the enhancement of relevant functional genes. The elevated abundance of mobile genetic elements (MGEs) and ARGs-carrying plasmids also demonstrated that MGE-mediated horizontal transfer was promoted by LDPE at 80 particles/g-TS. This effect was compounded by increased oxidative stress, cell membrane permeability, and cell cohesion, collectively facilitating horizontal ARG transfer. Consequently, both vertical and horizontal transfer of ARGs could be concurrently promoted by LDPE an in anaerobic sludge digester.

A Hybrid Data Preprocessing-Based Hierarchical Attention BiLSTM Network for Remaining Useful Life Prediction of Spacecraft Lithium-Ion Batteries.

As a crucial energy storage for the spacecraft power system, lithium-ion batteries degradation mechanisms are complex and involved with external environmental perturbations. Hence, effective remaining useful life (RUL) prediction and model reliability assessment confronts considerable obstacles. This article develops a new RUL prediction method for spacecraft lithium-ion batteries, where a hybrid data preprocessing-based deep learning model is proposed. First, to improve the correlation between battery capacity and features, the empirically selected high-dimensional features are linearized by using the Box-Cox transformation and then denoised via the complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) method. Second, the principal component analysis (PCA) algorithm is employed to perform feature dimensionality reduction, and the output of PCA is further processed by the sliding window technique. Third, a multiscale hierarchical attention bi-directional long short-term memory (MHA-BiLSTM) model is constructed to estimate the capacity in future cycles. Specifically, the MHA-BiLSTM model can predict the RUL of lithium-ion batteries by considering the correlation and significance of each cycle's information during the degradation process on different scales. Finally, the proposed method is validated based on multiple types of experiments under two lithium-ion battery datasets, demonstrating its superior performance in terms of feature extraction and multidimensional time series prediction.

Rapid label-free detection of early-stage lung adenocarcinoma and tumor boundary via multiphoton microscopy.

Lung cancer is the most commonly diagnosed cancer and the leading cause of cancer-related deaths in China. Rapid and precise evaluation of tumor tissue during lung cancer surgery can reduce operative time and improve negative-margin assessment, thus increasing disease-free and overall survival rates. This study aimed to explore the potential of label-free multiphoton microscopy (MPM) for imaging adenocarcinoma tissues, detecting histopathological features, and distinguishing between normal and cancerous lung tissues. We showed that second harmonic generation (SHG) signals exhibit significant specificity for collagen fibers, enabling the quantification of collagen features in lung adenocarcinomas. In addition, we developed a collagen score that could be used to distinguish between normal and tumor areas at the tumor boundary, showing good classification performance. Our findings demonstrate that MPM imaging technology combined with an image-based collagen feature extraction method can rapidly and accurately detect early-stage lung adenocarcinoma tissues.

The diagnosis and treatment of central retinal artery occlusion with severe cardio-cerebrovascular disease: a case report.

Background: Central retinal artery occlusion (CRAO) is an acute eye disease that seriously damages vision. Patients with CRAO often have a combination of various cardio-cerebrovascular diseases (CCVDs), and CRAO patients often ignore their cardio-cerebrovascular disorders because of their ocular symptoms. In addition, there are few reports about CRAO patients with CCVDs received effective interventions implemented. We report the diagnosis and treatment of a Chinese CRAO patient with CCVD who received timely multidisciplinary interventional therapy to provide ideas for clinical ophthalmologists in the diagnosis and treatment of similar diseases. Case Description: A 76-year-old male patient, who had previously been diagnosed with hypertension, was admitted to hospital due to a sudden decrease in vision in his right eye for >2 days with a severe headache. After fundus photography, he was diagnosed with CRAO in the right eye. His cerebral angiography revealed multiple stenoses at arteries of his neck and brain included the right ophthalmic artery. Neurosurgery was attempted to perform a thrombolysis of the right ophthalmic artery while performing the angiography, but failed to find the opening of the right ophthalmic artery. However, through electrocardiogram (ECG) monitoring during the operation, we found that the patient had frequent ventricular premature beats, so the Department of Cardiology performed coronary arteriography for him which revealed severe stenosis of the left anterior descending (LAD) artery. The cardiologists performed a percutaneous coronary intervention (PCI) at the same time as the coronary angiography. Some 2 months later, the patient was admitted to the Neurosurgery Department to implant stent at the left vertebral artery. After stent implantation, his headache symptom improved significantly and his right eye vision improved. Conclusions: Through timely cerebral angiography and ophthalmic examinations, the patient was diagnosed with CRAO combined with CCVD, and after received multidisciplinary interventional therapy, the patient's right eye vision and headache symptom improved and more severe cardio-cerebrovascular adverse events were avoided. In treating CRAO patients, in addition to aggressive eye treatment, the systemic cardio-cerebrovascular situation of each patient should also be assessed, a timely diagnosis made, and effective interventions implemented to reduce morbidity- and mortality-related cardio-cerebrovascular events.

Oxidized Zirconium Versus Cobalt Chromium for Primary TKA: No Difference in Midterm Revision Rates From the American Joint Replacement Registry.

BACKGROUND: Cobalt chromium (CoCr) is the most commonly used material in TKA; however, the use of oxidized zirconium (OxZr) implants has increased. The advantages to this material demonstrated in basic science studies have not been borne out in clinical studies to date. QUESTION/PURPOSE: In the setting of the American Joint Replacement Registry (AJRR), how do revision rates differ between CoCr and OxZr after primary TKA? METHODS: The AJRR was accessed for all primary TKAs performed between 2012 and 2020 for osteoarthritis, resulting in 441,605 procedures (68,506 with OxZr and 373,099 with CoCr). The AJRR is the largest joint replacement registry worldwide and collects procedure-specific details, making it ideal for large-scale comparisons of implant materials in the United States. Competing risk survival analyses were used to evaluate the all-cause revision rates of primary TKAs, comparing CoCr and OxZr implants. Data from the Centers for Medicare and Medicaid Services claims from 2012 to 2017 were also cross-referenced to capture additional revisions from other institutions. Revision rates were tabulated and subclassified by indication. Multivariate Cox regression was used to account for confounding variables such as age, gender, region, and hospital size. RESULTS: After controlling for confounding variables, there were no differences between the OxZr and CoCr groups in terms of the rate of all-cause revision at a mean follow-up of 46 ± 23 months and 44 ± 24 months for CoCr and OxZr implants, respectively (hazard ratio 1.055 [95% confidence interval 0.979 to 1.137]; p = 0.16) The univariate analysis demonstrated increased rates of revisions for pain and instability in the OxZr group (p = 0.003 and p < 0.001, respectively). CONCLUSION: These findings suggest there is no difference in all-cause revision between OxZr and CoCr implants in the short-term to mid-term. However, further long-term in vivo studies are needed to monitor the safety and all-cause revision rate of OxZr implants compared with those of CoCr implants. OxZr implants may be favorable in patients who have sensitivity to metal. Despite similar short-term to mid-term all-cause revision rates to CoCr implants, because of the limitations of this study, definitive recommendations for or against the use of OxZr cannot be made. LEVEL OF EVIDENCE: Level III, therapeutic study.

Different microplastics distinctively enriched the antibiotic resistance genes in anaerobic sludge digestion through shifting specific hosts and promoting horizontal gene flow.

Both microplastics (MPs) and antibiotic resistance genes (ARGs) are intensively detected in waste activated sludge (WAS). However, the distinctive impacts of different MPs on ARGs emergence, dissemination, and its potential mechanisms remain unclear. In this study, long-term semi-continuous digesters were performed to examine the profiles of ARGs and antibiotic-resistant bacteria (ARB) in response to two different typical MPs (polyethylene (PE) and polyvinyl chloride (PVC)) in anaerobic sludge digestion. Metagenomic results show that PE- and PVC-MPs increase ARGs abundance by 14.8% and 23.6% in digester, respectively. ARB are also enriched by PE- and PVC-MPs, Acinetobacter sp. and Salmonella sp. are the dominant ARB. Further exploration reveals that PVC-MPs stimulates the acquisition of ARGs by human pathogen bacteria (HPB) and functional microorganisms (FMs), but PE-MPs doesn't. Network analysis shows that more ARGs tend to co-occur with HBP and FMs after MPs exposure, and more importantly, new bacteria are observed to acquire ARGs possibly via horizontal gene flow (HGF) in MPs-stressed digester. The genes involved in the HGF process, including reactive oxygen species (ROS) production, cell membrane permeability, extracellular polymeric substances (EPS) secretion, and ATP synthesis, are also enhanced by MPs, thereby attributing to the promoted ARGs dissemination. These findings offer advanced insights into the distinctive contribution of MPs to fate, host, dissemination of ARGs in anaerobic sludge digestion.

Effects of combination therapy with Shenfu Injection in critically ill patients with septic shock receiving mechanical ventilation: A multicentric, real-world study.

Background: Septic shock has increasingly become a cause of death threatening human survival. Shenfu Injection (SFI), a patented Chinese medicine, has been widely used in the treatment of patients with sepsis and cardiovascular diseases domestically. We sought to examine whether combination therapy with SFI can improve clinical outcomes in critically ill patients undergoing mechanical ventilation (MV). Methods: This real-world, multicenter retrospective trial enrolled consecutive adult patients with sepsis requiring MV from four medical/surgical intensive care units (ICUs) in China between August 2016 and September 2021. Patients were identified from the medical information department database of each center and assigned to either of two groups (SFI or control) on the basis of the initial treatment received. The primary outcome was 28-day all-cause mortality, and the durations of vasopressor therapy and MV, the ICU length of stay, and costs were assessed as secondary outcomes. Subsequently, we performed a meta-analysis of randomized controlled trials (RCTs) on SFI published before July 2021 to verify our conclusions. Results: 2311 mechanically ventilated patients with septic shock (1128 patients in the SFI group and 1183 in the control group) were analyzed. The survival probability during the first 28 days after admission in the SFI group was greater than that in the control group [p < 0.01 by log-rank test; hazard ratio (HR), 0.56; 95% confidence interval (CI), 0.39-0.72]. Patients in the SFI group also experienced a significantly reduced duration of vasopressor therapy [7.28 (95% CI, 6.14-8.42) vs. 12.06 (95% CI, 10.71-13.41) days, p < 0.001], more ventilator-free days [6.49 (95% CI, 5.42-7.55) vs. 10.84 (95% CI, 9.59-12.09) days, p < 0.001], a shorter ICU length of stay [18.48 (95% CI, 17.59-19.38) vs. 23.77 (95% CI, 22.47-25.07) days, p < 0.001], and more time free from organ failure [14.23 (95% CI, 12.94-15.52) vs. 19.07 (95% CI, 16.09-22.05) days, p < 0.001]. No major adverse effects were reported in either group. Conclusion: Among critically ill patients requiring MV, combination therapy with SFI can improve the survival probability without any obvious adverse reactions.

A Dissemination Model Based on Psychological Theories in Complex Social Networks.

Information spread on social media has been extensively studied through both model-driven theoretical research and data-driven case studies. Recent empirical studies have analyzed the differences and complexity of information dissemination, but theoretical explanations of its characteristics from a modeling perspective are underresearched. To capture the complex patterns of the information dissemination mechanism, we propose a resistant linear threshold (RLT) dissemination model based on psychological theories and empirical findings. In this article, we validate the RLT model on three types of networks and then quantify and compare the dissemination characteristics of the simulation results with those from the empirical results. In addition, we examine the factors affecting dissemination. Finally, we perform two case studies of the 2019 novel Corona Virus Disease (COVID-19)-related information dissemination. The dissemination characteristics derived by the simulations are consistent with the empirical research. These results demonstrate that the RLT model is able to capture the patterns of information dissemination on social media and thus provide model-driven insights into the interpretation of public opinion, rumor control, and marketing strategies on social media.

Simultaneously Enhanced Hydrophilicity and Stability of a Metal-Organic Framework via Post-Synthetic Modification for Water Vapor Sorption/Desorption.

With increasing demands for high-performance water sorption materials, metal-organic frameworks (MOFs) have gained considerable attention due to their high maximum uptake capacities. In many cases, however, high overall capacity is not necessarily accomplishing high working capacity under operating conditions, due to insufficient hydrophilicity and/or water stability. Herein, we present a post-synthetic modification (PSM) of MOF-808, with di-sulfonic acids enhancing simultaneously its hydrophilicity and water stability without sacrificing its uptake capacity of ≈30 mmol g-1 . Di-sulfonic acid PSM enabled a shift of the relative humidity (RH) associated with a sharp step in water vapor sorption from 35-40 % RH in MOF-808 to below 25 % RH. While MOF-808 lost uptake capacity and crystallinity over multiple sorption/desorption cycles, the di-sulfonic acid PSM MOF-808 retained >80 % of the original capacity. PSM MOF-808 exhibited good hydrothermal stability up to 60 °C and high swing capacity.

Cholesterol affects the relationship between albumin and major adverse cardiac events in patients with coronary artery disease: a secondary analysis.

We aimed to examine whether the efficacy of the risk of poor prognosis in patients with coronary artery disease is jointly affected by total cholesterol and baseline serum albumin in a secondary analysis of previous study. We analyzed the data of 204 patients from October 2014 to October 2017 for newly diagnosed stable CAD. The outcome was major adverse cardiac events (MACE; defined as all cause mortality, non fatal myocardial infarction, and non fatal stroke). The median duration of follow-up was 783 days. Multivariable COX model was performed to revalidate the relationship between the sALB and MACE and interaction tests were conducted to find the effects of total cholesterol on their association. A total of 28 MACE occurred among the 204 participants. The risk of MACE varied by baseline serum albumin and total cholesterol. Specifically, lower serum albumin indicated higher risk of MACE (HR 3.52, 95% CI 1.30-9.54), and a test for interaction between baseline serum albumin and total cholesterol on MACE was significant (P = 0.0005). We suggested that baseline serum albumin and total cholesterol could interactively affect the risk of poor prognosis of patients with coronary artery diseases. Our findings need to be confirmed by further randomized trials.

The Effect of State-Level Prescription Opioid Legislation on Patient Outcomes After Lumbar Tubular Microdecompression.

BACKGROUND: In the United States, a statewide legislation titled the Strengthen Opioid Misuse Prevention (STOP) Act was enacted in 2017 to limit prescription opioid use and reduce dependence. The impact of state legislation curbing opioid prescription on outcomes after spine surgery is unknown. STUDY DESIGN: Case series. METHODS: Data from consecutive patients undergoing lumbar tubular microdecompression for symptomatic lumbar spine stenosis from June 2016 to June 2019 were retrospectively analyzed. Cases between June 2016 and December 2017 represent the group before the STOP act (pre-STOP), while cases between January 2018 and June 2019 represent the group after legislation enactment (post-STOP). Preoperative and postoperative patient functional scores including the EuroQol-Five Dimensions Index, Oswestry Disability Index (ODI), and the visual analog scale (VAS) for back and leg pain were compared between both groups. The meaningful clinically important difference (MCID) was calculated for each score and was compared between both groups as well. RESULTS: A total of 147 patients met inclusion criteria, with 86 in the pre-STOP group and 61 in the post-STOP group. Analysis of postoperative scores demonstrated statistically lower VAS leg pain score averages in the post-STOP group (P < 0.05). Higher trends in achieving MCID among the post-STOP group were observed; however, the differences between both groups were not statistically significant (P > 0.05 for all). Additionally, there were no statistical differences in rates of unplanned pain-related clinic visits and emergency department (ED) visits, as well as no differences in the number of pain-related calls within 90 days after surgery between both groups. CONCLUSION: The enactment of state legislation to curb the prescribing of opioids for postoperative pain did not negatively affect the rate of achieving clinically meaningful outcomes among patients undergoing lumbar tubular microdecompression for spinal stenosis. Additionally, decreasing the amount of opioids prescribed for postoperative pain does not increase the number of unplanned clinic or ED visits due to pain within 90 days after surgery.

Role of Asymptomatic COVID-19 Cases in Viral Transmission: Findings From a Hierarchical Community Contact Network Model.

As part of ongoing efforts to contain the coronavirus disease (COVID-19) pandemic, understanding the role of asymptomatic patients in the transmission system is essential for infection control. However, the optimal approach to risk assessment and management of asymptomatic cases remains unclear. This study proposed a Susceptible, Exposed, Infectious, No symptoms, Hospitalized and reported, Recovered, Death (SEINRHD) epidemic propagation model. The model was constructed based on epidemiological characteristics of COVID-19 in China and accounting for the heterogeneity of social contact networks. The early community outbreaks in Wuhan were reconstructed and fitted with the actual data. We used this model to assess epidemic control measures for asymptomatic cases in three dimensions. The impact of asymptomatic cases on epidemic propagation was examined based on the effective reproduction number, abnormally high transmission events, and type and structure of transmission. Management of asymptomatic cases can help flatten the infection curve. Tracing 75% of the asymptomatic cases corresponds to a 32.5% overall reduction in new cases (compared with tracing no asymptomatic cases). Regardless of population-wide measures, household transmission is higher than other types of transmission, accounting for an estimated 50% of all cases. The magnitude of tracing of asymptomatic cases is more important than the timing; when all symptomatic patients were traced, tested, and isolated in a timely manner, the overall epidemic was not sensitive to the time of implementing the measures to trace asymptomatic patients. Disease control and prevention within families should be emphasized during an epidemic. Note to Practitioners-This article addresses the urgent need to assess the risk of another COVID-19 outbreak caused by asymptomatic cases and to find the optimal, most practical approach to asymptomatic case management. Previous studies mostly focused on the clinical and statistical characteristics of asymptomatic cases; few have evaluated the impact of asymptomatic case measures using mathematical modeling at the community scale. This study proposed a Susceptible, Exposed, Infectious, No symptoms, Hospitalized and reported, Recovered, Death (SEINRHD) propagation model based on local community structures and social contact networks, according to the development characteristics and trend of COVID-19 in a Chinese community. The conclusion provides theoretical support for emergency work of relevant departments in different periods of an epidemic. In the early stages of the epidemic, timely detection and isolation of symptomatic patients should be a priority. Where there are surplus resources for epidemic prevention, the authorities should consider increasing the proportion of asymptomatic patients being traced. Epidemic prevention measures among family members should be a primary focus of attention. This combination of strategies can help reduce the rate of viral transmission and result in extinguishing the epidemic.

Performance and Mechanism of Fe3O4 Improving Biotransformation of Waste Activated Sludge into Liquid High-Value Products.

This study demonstrated that Fe3O4 simultaneously improves the total production and formation rate of medium-chain fatty acids (MCFAs) and long-chain alcohols (LCAs) from waste activated sludge (WAS) in anaerobic fermentation. Results revealed that when Fe3O4 increased from 0 to 5 g/L, the maximal MCFA and LCA production increased significantly, and the optimal fermentation time was also remarkably shortened from 24 to 9 days. Moreover, Fe3O4 also enhanced WAS degradation, and the corresponding degradation rate in the fermentation system increased from 43.86 to 72.38% with an increase in Fe3O4 from 0 to 5 g/L. Further analysis showed that Fe3O4 promoted the microbe activities of all the bioprocesses (including hydrolysis, acidogenesis, and chain elongation processes) involved in the MCFA and LCA production from WAS. Microbial community analysis indicated that Fe3O4 increased the abundances of key microbes involved in abovementioned bioprocesses correspondingly. Mechanistic investigations showed that Fe3O4 increased the conductivity of the fermented sludge, providing a better conductive environment for the anaerobic microbes. The redox cycle of Fe(II) and Fe(III) existed in the fermentation system with Fe3O4, which was likely to act as electron shuttles to conduct electron transfer (ET) from the electron donor to the acceptor, thus increasing ET efficiency. This study provides an effective method for enhancing the biotransformation of WAS into high-value products, potentially bringing economic benefits to WAS treatment.

Two-dimensional Zr/Hf-hydroxamate metal-organic frameworks.

Novel two-dimensional kagome metal-organic frameworks with mononuclear Zr4+/Hf4+ nodes chelated by benzene-1,4-dihydroxamate linkers were synthesized. The MOFs, namely SUM-1, are chemically robust and kinetically favorable, as confirmed by theoretical and experimental studies. SUM-1(Zr) can be readily made into large (∼100 µm) single crystals and nanoplates (∼50 nm), constituting a versatile MOF platform.

A Review on the Design of Hydrogels With Different Stiffness and Their Effects on Tissue Repair.

Tissue repair after trauma and infection has always been a difficult problem in regenerative medicine. Hydrogels have become one of the most important scaffolds for tissue engineering due to their biocompatibility, biodegradability and water solubility. Especially, the stiffness of hydrogels is a key factor, which influence the morphology of mesenchymal stem cells (MSCs) and their differentiation. The researches on this point are meaningful to the field of tissue engineering. Herein, this review focus on the design of hydrogels with different stiffness and their effects on the behavior of MSCs. In addition, the effect of hydrogel stiffness on the phenotype of macrophages is introduced, and then the relationship between the phenotype changes of macrophages on inflammatory response and tissue repair is discussed. Finally, the future application of hydrogels with a certain stiffness in regenerative medicine and tissue engineering has been prospected.

Reconstruction of the Transmission Chain of COVID-19 Outbreak in Beijing's Xinfadi Market, China.

OBJECTIVES: The aim of the study was to reconstruct the complete transmission chain of the COVID-19 outbreak in Beijing's Xinfadi Market using data from epidemiological investigations, which contributes to reflecting transmission dynamics and transmission risk factors. METHODS: We set up a transmission model, and the model parameters are estimated from the survey data via Markov chain Monte Carlo sampling. Bayesian data augmentation approaches are used to account for uncertainty in the source of infection, unobserved onset, and infection dates. RESULTS: The rate of transmission of COVID-19 within households is 9.2%. Older people are more susceptible to infection. The accuracy of our reconstructed transmission chain was 67.26%. In the gathering place of this outbreak, the Beef and Mutton Trading Hall of Xinfadi market, most of the transmission occurs within 20 m, only 19.61% of the transmission occurs over a wider area (>20 m), with an overall average transmission distance of 13.00 m. The deepest transmission generation is 9. In this outbreak, there were 2 abnormally high transmission events. CONCLUSIONS: The statistical method of reconstruction of transmission trees from incomplete epidemic data provides a valuable tool to help understand the complex transmission factors and provides a practical guideline for investigating the characteristics of the development of epidemics and the formulation of control measures.