The effects of coronaviruses on the respiratory system are of great concern, but their effects on the digestive system receive much less attention. Coronaviruses that infect mammals have shown gastrointestinal pathogenicity and caused symptoms such as diarrhea and vomiting. Available data have shown that human coronaviruses, including the newly emerged SARS-CoV-2, mainly infect the respiratory system and cause symptoms such as cough and fever, while they may generate gastrointestinal symptoms. However, there is little about the relation between coronavirus and digestive system. This review specifically addresses the effects of mammalian and human coronaviruses, including SARS-CoV-2, on the digestive tract, helping to cope with the new virus infection-induced disease, COVID-19.

Compared with non-degradable materials, biodegradable biomaterials play an increasingly important role in the repairing of severe bone defects, and have attracted extensive attention from researchers. In the treatment of bone defects, scaffolds made of biodegradable materials can provide a crawling bridge for new bone tissue in the gap and a platform for cells and growth factors to play a physiological role, which will eventually be degraded and absorbed in the body and be replaced by the new bone tissue. Traditional biodegradable materials include polymers, ceramics and metals, which have been used in bone defect repairing for many years. Although these materials have more or fewer shortcomings, they are still the cornerstone of our development of a new generation of degradable materials. With the rapid development of modern science and technology, in the 21st century, more and more kinds of new biodegradable materials emerge in endlessly, such as new intelligent micro-nano materials and cell-based products. At the same time, there are many new fabrication technologies of improving biodegradable materials, such as modular fabrication, 3D and 4D printing, interface reinforcement and nanotechnology. This review will introduce various kinds of biodegradable materials commonly used in bone defect repairing, especially the newly emerging materials and their fabrication technology in recent years, and look forward to the future research direction, hoping to provide researchers in the field with some inspiration and reference.

Military drill injury is a significant part of military medical research. The increase of training intensity and changes in training methods lead to differences in injury types. The ideal therapeutic modality should allow rapid healing at a reasonable cost and minimize impact on patients’ life. Platelet-rich plasma (PRP), a platelet concentrate, is rich in a variety of growth factors and widely used clinically as a minimally invasive treatment. It plays an important role in injury repair and rehabilitation. In this article, we review the therapeutic role of PRP in military drill injury and its possible underlying mechanisms, with a focus on plantar fasciitis, stress fractures and other common injuries, in order to provide basic support for military reserve.

Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused millions of infections and deaths worldwide since its emergence in December 2019. As there is little or no natural immunity in the human population or specific anti-COVID-19 drugs, researchers from the government, academia and industry are developing vaccines at an unprecedented speed to halt the pandemic. In this review, the results of animal experiments and clinical trials on several vaccine technical platforms are summarized, and several challenges are also discussed to further promote the development, evaluation and application of vaccines during the challenging situation of the global pandemic.

Microwave radiation has been widely used in various fields, such as communication, industry, medical treatment, and military applications. Microwave radiation may cause injuries to both the structures and functions of various organs, such as the brain, heart, reproductive organs, and endocrine organs, which endanger human health. Therefore, it is both theoretically and clinically important to conduct studies on the biological effects induced by microwave radiation. The successful establishment of injury models is of great importance to the reliability and reproducibility of these studies. In this article, we review the microwave exposure conditions, subjects used to establish injury models, the methods used for the assessment of the injuries, and the indicators implemented to evaluate the success of injury model establishment in studies on biological effects induced by microwave radiation.

Background: Soft tissue reconstruction is typically conducted after evacuation from theater of operations. If circumstances do not allow timely evacuation, however, defect site may need to be reconstructed in the combat zone.

Case presentation: A total of 41 patients with extremity soft tissue defect were treated using pedicled flaps by a single orthopedic surgeon during four deployments in Chad, Afghanistan and Mali between 2010 and 2017. The mean age was 25.6 years. A total of 46 injury sites in extremities required flap coverage: 19 combat-related injuries (CRIs) and 27 non-combat related injuries (NCRIs). Twenty of the injury sites were infected. Overall, 63 pedicled flap transfers were carried out: 15 muscle flaps, 35 local fasciocutaneous flaps and 13 distant fasciocutaneous flaps. The flap types used did not differ for CRIs or NCRIs. Mean follow-up was 71 days. Complications included deep infection (n=6), flap failure (n=1) and partial flap necrosis (n=1). Limb salvage rate was 92.7% (38/41).

Conclusions: Soft tissue defect can be managed with simple pedicled flaps in theatre of operations if needed. Basic reconstructive procedures should be part of the training for military orthopedic surgeons.

Trial registration: Retrospectively registered in January 2019 (2019-0901-001).

Sepsis is a life-threatening condition that is characterized by multiple organ dysfunction due to abnormal host response to various pathogens, like bacteria, fungi and virus. The differences between viral and bacterial sepsis are indeed of great significance to deepen the understanding of the pathogenesis of sepsis, especially under pandemics of SARS-CoV-2 infection.

Background: Civilian explosion blast injury is more frequent in developing countries, including China. However, the incidence, casualties, and characteristics of such incidents in China are unknown.

Methods: This is a retrospective analysis of the State Administration of Work Safety database. Incidents during a period from January 1, 2000 to April 30, 2017 were included in the analysis. The explosions were classified based on the number of deaths into extraordinarily major, major, serious and ordinary type. Descriptive statistics was used to analyze the incidence and characteristics of the explosions. Correlation analysis was performed to examine the potential correlations among various variables.

Results: Data base search identified a total of 2098 explosions from 2000 to 2017, with 29,579 casualties: 15,788 deaths (53.4%), 12,637 injured (42.7%) and 1154 missing (3.9%). Majority of the explosions were serious type (65.4%). The number of deaths (39.5%) was also highest with the serious type (P=0.006). The highest incidence was observed in the fourth quarter of the year (October to December), and at 9:00–11:00 am and 4:00–6:00 pm of the day. The explosions were most frequent in coal-producing provinces (Guizhou and Shanxi Province). Coal mine gas explosions resulted majority of the deaths (9620, 60.9%). The number of explosion accidents closely correlated with economic output (regional economy and national GDP growth rate) (r=–0.372, P=0.040; r=0.629, P=0.028).

Conclusions: The incidence and civilian casualties due to explosions remain unacceptable in developing China. Measures that mitigate the risk factors are of urgently required.

Background: Recent studies reported that patients with coronavirus disease-2019 (COVID-19) might have liver injury. However, few data on the combined analysis and change patterns of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and total bilirubin (TBil) have been shown.

Methods: This is a single-center retrospective study. A total of 105 adult patients hospitalized for confirmed COVID-19 in Beijing Ditan Hospital between January 12, and March 17, 2020 were included, and divided into mild group (n=79) and severe group (n=26). We compared liver functional test results between the two groups. Category of ALT change during the disease course was also examined.

Results: 56.2%(59/105) of the patients had unnormal ALT, AST, or total TBil throughout the course of the disease, but in 91.4%(96/105) cases the level of ALT, AST or TBil ≤3 fold of the upper limit of normal reference range (ULN). The overall distribution of ALT, AST, and TBil were all significantly difference between mild and severe group (P<0.05). The percentage of the patients with elevated both ALT and AST was 12.7%(10/79) in mild cases vs. 46.2%(12/26) in severe cases (P=0.001). 34.6%(9/26) severe group patients started to have abnormal ALT after admission, and 73.3%(77/105) of all patients had normal ALT before discharge.

Conclusions: Elevated liver function index is very common in patients with COVID-19 infection, and the level were less than 3×ULN, but most are reversible. The abnormality of 2 or more indexes is low in the patients with COVID-19, but it is more likely to occur in the severe group.

Background: Pediatric casualties account for a notable proportion of encounters in the deployed setting based on the humanitarian medical care mission. Previously published data demonstrates that an age-adjust shock index may be a useful tool in predicting massive transfusion and death in children. We seek to determine if those previous findings are applicable to the deployed, combat trauma setting.

Methods: We queried the Department of Defense Trauma Registry (DODTR) for all pediatric subjects admitted to US and Coalition fixed-facility hospitals in Iraq and Afghanistan from January 2007 to January 2016. This was a secondary analysis of casualties seeking to validate previously published data using the shock index, pediatric age adjusted. We then used previously published thresholds to determine patients outcome for validation by age grouping, 1–3 years (1.2), 4–6 years (1.2), 7–12 years (1.0), 13–17 years (0.9).

Results: From January 2007 through January 2016 there were 3439 pediatric casualties of which 3145 had a documented heart rate and systolic pressure. Of those 502(16.0%) underwent massive transfusion and 226(7.2%) died prior to hospital discharge. Receiver operating characteristic (ROC) thresholds were inconsistent across age groups ranging from 1.0 to 1.9 with generally limited area under the curve (AUC) values for both massive transfusion and death prediction characteristics. Using the previously defined thresholds for validation, we reported sensitivity and specificity for the massive transfusion by age-group: 1–3(0.73, 0.35), 4–6(0.63, 0.60), 7–12(0.80, 0.57), 13–17(0.77, 0.62). For death, 1–3(0.75, 0.34), 4–6(0.66–0.59), 7–12(0.64, 0.52), 13–17(0.70, 0.57). However, negative predictive values (NPV) were generally high with all greater than 0.87.

Conclusions: Within the combat setting, the age-adjusted pediatric shock index had moderate sensitivity and relatively poor specificity for predicting massive transfusion and death. Better scoring systems are needed to predict resource needs prior to arrival, that perhaps include other physiologic metrics. We were unable to validate the previously published findings within the combat trauma population.