Seven-layer analysis model of an optical waveguide excitation fluorescence microscopy.

In this paper, an optical waveguide evanescent field fluorescence microscopy is studied. Based on Maxwell's equation, a seven-layer theoretical analysis model is developed for the evaluation of an optical waveguide excitation fluorescence microscopy. The optical waveguide excitation fluorescence microscopy structure is systematically and comprehensively analysed at the wavelengths of 488, 532 and 646 nm for fluorescent dyes. The analysis results provide some useful suggestions, which will be beneficial to the research of an optical waveguide evanescent field fluorescence microscopy.

A predictive model of macrosomic birth based upon real-world clinical data from pregnant women.

BACKGROUND: Fetal macrosomia is associated with an increased risk of several maternal and newborn complications. Antenatal predication of fetal macrosomia remains challenging. We aimed to develop a nomogram model for the prediction of macrosomia using real-world clinical data to improve the sensitivity and specificity of macrosomia prediction. METHODS: In the present study, we performed a retrospective, observational study based on 13,403 medical records of pregnant women who delivered singleton infants at a tertiary hospital in Shanghai from 1 January 2018 through 31 December 2019. We split the original dataset into a training set (n = 9382) and a validation set (n = 4021) at a 7:3 ratio to generate and validate our model. The candidate variables, including maternal characteristics, laboratory tests, and sonographic parameters were compared between the two groups. A univariate and multivariate logistic regression was carried out to explore the independent risk factors for macrosomia in pregnant women. Thus, the regression model was adopted to establish a nomogram to predict the risk of macrosomia. Nomogram performance was determined by discrimination and calibration metrics. All the statistical analysis was analyzed using R software. RESULTS: We compared the differences between the macrosomic and non-macrosomic groups within the training set and found 16 independent risk factors for macrosomia (P < 0.05), including biparietal diameter (BPD), head circumference (HC), femur length (FL), amniotic fluid index (AFI) at the last prenatal examination, pre-pregnancy body mass index (BMI), and triglycerides (TG). Values for the areas under the curve (AUC) for the nomogram model were 0.917 (95% CI, 0.908-0.927) and 0.910 (95% CI, 0.894-0.927) in the training set and validation set, respectively. The internal and external validation of the nomogram demonstrated favorable calibration as well as discriminatory capability of the model. CONCLUSIONS: Our model has precise discrimination and calibration capabilities, which can help clinical healthcare staff accurately predict macrosomia in pregnant women.

Atomically Dispersed Co to an End-Adsorbing Molecule for Excellent Biomimetically and Prime Sensitively Detecting O2•- Released from Living Cells.

Single-atom catalysis efficiently exposes the catalytic sites to reactant molecules while rendering opportunity to investigate the catalysis mechanisms at atomic levels for scientific insights. Here, for the first time, atomically dispersed Co atoms are synthesized as biomimetic "enzymes" to monitor superoxide anions (O2•-), delivering ultraordinary high sensitivity (710.03 µA·µM-1·cm-2), low detection limit (1.5 nM), and rapid response time (1.2 s), ranking the best among all the reported either bioenzymatic or biomimetic O2•- biosensors. The sensor is further successfully employed to real-time monitor O2•- released from living cells. Moreover, theoretical calculation and analysis associated with experimental results discover that a mode of end adsorption of the negatively charged O2•- on the Co3+ atom rather than a bridge or/and side adsorption of the two atoms of O2•- on two Co3+ atoms, respectively, plays an important role in the single-atomic catalysis toward O2•- oxidation, which not only facilitates faster electron transfer but also offers better selectivity. This work holds great promise for an inexpensive and sensitive atomic biomimetic O2•- sensor for bioresearch and clinic diagnosis, while revealing that the adsorption mode plays a critical role in single-atom catalysis for a fundamental insight.

[Ecological stoichiometric characteristics of soil and microbial biomass C, N, P in rhizosphere soil of Paris polyphylla and Panax japonicus cultivated understory].

Comparison of total organic carbon(TOC), total nitrogen(TN), total phosphorus(TP), soil microbial biomass carbon(MBC), nitrogen(MBN), phosphorus(MBP) and their stoichiometric ratios measuring from understory planting of Paris polyphylla and Panax japonicus rhizosphere soil with the data of the original forest soil will help us to understand the influence of different planting patterns between soil traits and soil microbial interaction and nutrient cycle characteristics. The results showed that the contents of TOC, TN and MBN were the highest in the rhizosphere soil of P. japonicus, while the highest values of TP, MBC and MBP were found in the rhizosphere soil of P. polyphylla. The changes of TOC∶TN, TOC∶TP, TN∶TP, MBC∶MBN, MBC∶MBP and MBN∶MBP of P. polyphylla and P. japonicus rhizosphere soil compared with the data of the original forest soil were 3.65 and 37.32%,-14.89 and 82.23%,-17.87 and 32.76%, 25.67 and-50.60%,-75.95 and-16.33% as well as-80.79 and 69.76%, respectively. TN and TP were significantly correlated with MBN and MBP respectively. Although, monoculture of P. polyphylla and P. japonicus changed soil nutrient level, it did not reach the state of nutrient deficiency. The demands for nitrogen and phosphorus between P. polyphylla and P. japonicus were quite different. According to their different habits, monoculture of P. polyphylla and P. japonicus could change the understory soil traits, resulting in allometric changes in part of soil nutrient stoichiometry and soil microbial stoichiometry, and then the disappearance of internal stability. The variations in the understory soil caused by P. polyphylla and P. japonicus is developing in completely different directions, whether this phenomenon indicates that the two species have less niche overlap needs further study.

INSULIN RESISTANCE AND POLYCYSTIC OVARY SYNDROME IN A CHINESE POPULATION.

OBJECTIVE: Our study aimed to investigate glucose and lipid level as well as insulin resistance (IR) in patients with polycystic ovary syndrome (PCOS). METHODS: In a case-control study, 426 patients with PCOS were diagnosed according to Rotterdam criteria, and they were conducted in the morning after a 10-h fast. Participants received standard 75-g oral glucose tolerance test (OGTT). Plasma glucose and insulin levels were obtained at 0, 30, 60, 120, and 180 min. They also received the lipid evaluation; 95 healthy women with normal menstrual cycles served as controls. Thus, by modifying the homeostasis model assessment of insulin resistance (HOMA-IR) with the use of individual time-course values of glucose and insulin plasma levels, we developed a new assessment method, HOMA-Mx. RESULTS: In our study, 23.71% of patients had abnormal glucose metabolism. With further impairment in glucose metabolism, the glucose and lipid level gradually increased (P<0.05), while the impaired glucose regulation (IGR) group showed greater insulin response than a type 2 diabetes mellitus (T2DM) group. Compared with healthy controls, both lean and obese PCOS patients with normal glucose tolerance (NGT) had a higher body mass index (BMI), and higher serum glucose, insulin, and lipid values. Additionally, the insulin value peaked at 30 min and 60 min in the lean and obese groups, respectively. HOMA-M30 proved to be the best predictive parameter (cutoff: 20.36, area under the curve [AUC]: 0.753) for assessment of IR in normal-weight patients and HOMA-IR (cutoff: 32.17, AUC: 0.868) was optimal in obese PCOS patients. CONCLUSIONS: A new assessment method was developed for these groups: HOMA-M30 for lean PCOS patients and HOMA-M60 for obese patients, in order to focus on peak insulin values for early detection of IR.

Linear-in-wavenumber swept laser with an acousto-optic deflector for optical coherence tomography.

We report a novel linear-in-wavenumber (k-linear) swept laser source based on an acousto-optic deflector (AOD). The AOD-based optical filter includes an acousto-optic deflector and a reflection grating. The laser may tune k linearly in wavenumber over time due to its appropriate configuration and is favorable for fast imaging because it avoids data resampling and recalibration, as are required in conventional swept source optical coherence tomography (SS-OCT). We achieved k-linearity with Pearson's r correlation coefficients of 0.99995 without and 0.99997 with optimization. The laser has a tuning range of 50 nm, a 3 dB swept range of 42 nm (FWHM), output power of 2.56 mW, 6 dB sensitivity roll-off depth of 0.941 mm, and central wavelength of 1064 nm at a scanning rate of ∼20 kHz. Scanning rate as high as ∼400 kHz is also achieved for this laser with the tuning range 49 nm, swept linearity of 0.99990, output power of 2.30 mW, and a 6 dB sensitivity roll-off depth 0.550 mm. SS-OCT imaging with linear-in-wavenumber swept laser is also demonstrated.

Differential metabolite analysis of the pharmacodynamic differences between different ratios of Dahuang ()-Taoren () herb pair.

OBJECTIVE: To explore the material basis of the difference of efficacy of Dahuang (Radix Et Rhizoma Rhei Palmati)-Taoren (Semen Persicae) (DT) drugs with different proportions. METHODS: Samples of different ratios of Dahuang (Radix et Rhizoma Rhei Palnati, DH) to Taoren (Semen Persicae, TR) (Group A 1:1, B 2:3, C 3:2) were analyzed based on gas chromatography time-of-flight mass spectrometry untargeted metabolomics technique. RESULTS: A total of 240 primary metabolites were detected. Forty-one differential metabolites involved nine differential metabolic pathways, of which four were closely related to the efficacy of DT in the treatment of heat and blood stasis syndrome. These pathways included the biosynthesis of amino acid (phenylalanine tyrosine and tryptophan), flavonoids, unsaturated fatty acids, and the glycolysis/glycogenesis pathway. CONCLUSION: There are significant differences in the efficacy of different ratios of DT drugs, and their optimal ratio for the treatment of heat and blood stasis syndrome should be 1:1.

Co-expression of soluble guanylyl cyclase subunits and PDE5A shRNA to elevate cellular cGMP level: A potential gene therapy for myocardial cell death.

BACKGROUND: Genetic manipulation on the NO-sGC-cGMP pathway has been rarely achieved, partially due to complexity of the soluble guanylyl cyclase (sGC) enzyme. OBJECTIVE: We aim to develop gene therapy directly targeting the pathway to circumvent cytotoxicity and tolerance after prolonged use of NO-donors and the insufficiency of PDE inhibitors. METHODS: In this study, we constructed lentivirus vectors expressing GUCY1A3 and GUCY1B3 genes, which encoded the α1 and ß1 subunits of soluble guanylyl cyclase (sGC), respectively, to enhance cGMP synthesis. We also constructed lentiviral vector harboring PDE5A shRNA to alleviate phosphodiesterase activity and cGMP degradation. RESULTS: Transductions of human HEK293 cells with the constructs were successful, as indicated by the fluorescent signal and altered gene expression produced by each vector. Overexpression of GUCY1A3 and GUCY1B3 resulted in increased sGC enzyme activity and elevated cGMP level in the cells. Expression of PDE5A shRNA resulted in decreased PDE5A expression and elevated cGMP level. Co-transduction of the three lentiviral vectors resulted in a more significant elevation of cGMP in HEK293 cells without obvious cytotoxicity. CONCLUSION: To the best of our knowledge, this is the first study to show that co-expression of exogenous subunits of the soluble guanylyl cyclase could form functional enzyme and increase cellular cGMP level in mammalian cells. Simultaneous expression of PDE5A shRNA could alleviate feedback up-regulation on PDE5A caused by cGMP elevation. Further studies are required to evaluate the effects of these constructs in vivo.

Compressed sensing with linear-in-wavenumber sampling in spectral-domain optical coherence tomography.

We propose a novel method called compressed sensing with linear-in-wavenumber sampling (k-linear CS) to retrieve an image for spectral-domain optical coherence tomography (SD-OCT). An array of points that is evenly spaced in wavenumber domain is sampled from an original interferogram by a preset k-linear mask. Then the compressed sensing based on l1 norm minimization is applied on these points to reconstruct an A-scan data. To get an OCT image, this method uses less than 20% of the total data as required in the typical process and gets rid of the spectral calibration with numerical interpolation in traditional CS-OCT. Therefore k-linear CS is favorable for high speed imaging. It is demonstrated that the k-linear CS has the same axial resolution performance with ~30 dB higher signal-to-noise ratio (SNR) as compared with the numerical interpolation. Imaging of bio-tissue by SD-OCT with k-linear CS is also demonstrated.

Oral epidemic diseases of exposure personnel in long-term low dose radiation.

Oral epidemic diseases of exposure personnel in long-term low-dose radiation yet have rarely been studied. Referred to WHO oral health survey method and symptom grading standard, data of 341 exposure persons in long-term low-dose radiation including α particle, ß particle, and γ rays, etc., were collected from one camp in China in 2011 with cluster sampling and analyzed? with Foxpro 6.0 and SPSS 16.0 software. The exposure persons worked in low-dose radiation for a long time aged between 23 and 56, whose average age were 27.1 years old.In addition, their lengths of service were from 2 to 34 years (average 7.9 years) and average exposure time was 8 hours a day each year for more than three months. Average annual radiation dose equivalent was from 1.8 to 16.5 mSv (average 7.3 mSv). Total radiation dose equivalent was from 3.8 to 425.0 mSv (average 97.3 mSv).

GSH-responsive poly-resveratrol based nanoparticles for effective drug delivery and reversing multidrug resistance.

Cancer poses a serious threat to human health and is the most common cause of human death. Polymer-based nanomedicines are presently used to enhance the treatment effectiveness and decrease the systemic toxicity of chemotherapeutic agents. However, the disadvantage of currently polymeric carriers is without therapy procedure. Herein, for the first time, glutathione (GSH)-responsive polymer (PRES) with anti-cancer effect was synthesized following the condensation-polymerization method using resveratrol (RES) and 3,3'-dithiodipropionic acid. PRES can not only suppress the tumor cells growth but can also self-assemble into nanoparticles (∼93 nm) for delivering antitumor drugs, such as paclitaxel (PTX@PRES NPs). The system could achieve high drug loading (∼7%) and overcome multidrug resistance (MDR). The results from the in vitro studies revealed that the NPs formed of PRES were stable in the systemic circulation, while could be efficiently degraded in tumor cells high GSH environment. Results from cytotoxicity tests confirmed that PTX@PRES NPs could effectively suppress the growth of cancer cells (A549) and drug-resistant cells (A549/PTX). The NPs could also be used to significantly increase the therapeutic efficacy of the drugs in A549/PTX tumor-bearing mice. In vivo investigations also demonstrated that the PRES-based NPs exhibited tumor inhibition effects. In summary, we report that the GSH-responsive polymer synthesized by us exhibited multiple interesting functions and could be used for effective drug delivery. The polymer exhibited good therapeutic effects and could be used to overcome MDR. Thus, the synthesized system can be used to develop a new strategy for treating cancer.

Identification and management of vulval problems of the postmenopausal woman - Tips and tricks.

Vulval irritation and discomfort can be a common presentation to both primary and secondary care. These symptoms can become increasingly prevalent due to physiological changes, which occur to the female genitalia following menopausal transition or due to inflammatory conditions. The correct diagnosis and management can have a huge impact on the patients' quality of life. However, due to the nature of the symptoms, there can be delayed presentation to healthcare professionals. This article gives an overview of the most common benign vulval conditions in the post-menopausal woman, their clinical features and the diagnosis and initial management.

Research progress on the potential mechanism and application of lactobacillus in the prevention and treatment of acute myocardial infarction / 天津医药

With the development of clinical,basic medicine and metabolomics,intestinal flora has gradually become a focus of research and has been used in the diagnosis and treatment of several intestinal diseases.Lactobacillus can produce and regulate a variety of intestinal metabolites,and participate in lipid metabolism,thrombosis,inflammation and oxidative stress,and even ferroptosis,which may have an impact on the occurrence and development of cardiovascular diseases.This article reviews the role of lactobacillus in the regulation of metabolism,involvement in the pathophysiological mechanism of myocardial infarction and its clinical application in acute myocardial infarction,providing a new reference for the prevention and treatment of AMI.

Protective effects of tetramethylpyrazine analogue Z-11 on cerebral ischemia reperfusion injury.

The aim of our study was to investigate the effects of a new synthetic compound (E) -1- (E) -1- (2- hydroxy -5- chlorophenyl) -3- (3, 5, 6- three methyl pyrazine -2- based) -2- propylene -1 ketone, Z-11, a tetramethylpyrazine analogue, on cerebral ischemia reperfusion injury and the underlying mechanism. 240-260 g adult male Wistar rats were subjected to middle cerebral artery occlusion for 2 h, followed by 22 h of reperfusion. Z-11 (1.7, 3.4 and 6.8 mg/kg, i.p.), Edaravone (3 mg/kg, i.p.) and DMSO (1‰, i.p.) was administered at 2 h after the onset of ischemia. The rats' neurological score, infarct volume, and body weight change were tested, and some oxidative stress markers such as superoxide dismutase (SOD) activity, glutathione (GSH) and malondialdehyde (MDA) contents were evaluated after 22 h of reperfusion. Results showed that neurologic deficit, infarct volume and body weight change were ameliorated after cerebral ischemia reperfusion, and that Z-11 exhibits an excellent effect at a dosage of 6.8 mg/kg. This dose also reduced the content of MDA, and upregulated SOD activity and GSH content. Similarly, 6.8 mg/kg Z-11 treatment inhibited the reactive oxygen species content and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity, with the protein levels of Ras-related C3 botulinum toxin substrate1(Rac-1) and mitogenic oxidase (Nox2) downregulated even further. Moreover, the protein levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream anti-oxidant protein heme oxygenase-1 (HO-1) were upregulated. This indicates that Z-11 could play a protective role in cerebral ischemia-reperfusion injury, and that the protective effect of Z-11 may be related to improvements in the antioxidant capacity of brain tissue. The mechanisms are associated with enhancing oxidant defence systems via the activation of Nrf2/HO-1 and Rac-1/NADPH oxidase pathways.

Research progress on association between chronic diseases and herpes zoster / 中华全科医师杂志

Herpes zoster is an infectious skin disease caused by reactivation of the varicella-zoster virus with multiple manifestations and various complication clinically. Studies have confirmed that chronic diseases are one of the independent risk factors for HZ; and the common chronic diseases such as diabetes, cardiovascular disease, chronic obstructive pulmonary disease and rheumatoid arthritis are associated with the development of herpes zoster. In this article, we review the latest research progress on the clinical features of herpes zoster, its correlation with common chronic diseases and the prevention strategies to reduce the disease burden.

Treatment of Cerebral Ischemia-reperfusion Injury by Traditional Chinese Medicine Based on PI3K/Akt Signaling Pathway： A Review / 中国实验方剂学杂志

Cerebral ischemia/reperfusion injury （CIRI） is a complex cascade reaction process in which the blood flow and oxygen supply of brain tissue in the infarcted area recover after cerebral ischemia， resulting in secondary injury of ischemic brain tissue. At present， thrombolysis as soon as possible and restoration of cerebral blood supply are still the only strategies for the treatment of stroke， but a considerable number of patients' symptoms will be more serious after reperfusion， making patients face adverse outcomes such as neurological function injury and even death and seriously affecting the quality of life and safety of patients. Therefore， an in-depth exploration of the mechanism and treatment strategy of CIRI has important clinical significance. The phosphatidylinositol 3- kinase （PI3K）/protein kinase B （Akt） signaling pathway is one of the classic anti-apoptosis/reproductive-promoting signal transduction pathways， which is responsible for cell proliferation， growth， and differentiation. It is the key cascade signaling pathway of CIRI， located at the core site in many mechanisms such as mitochondrial disorder， apoptosis， autophagy， oxidative stress， and inflammation. It is closely related to the occurrence and development of CIRI. Traditional Chinese medicine has been used in the clinical treatment of stroke and its complications for thousands of years， and the clinical effect of traditional Chinese medicine in the prevention and treatment of CIRI has been affirmed by a large number of research results in recent years. It is further clarified that the monomers， active components， and their compound prescriptions of traditional Chinese medicine can directly or indirectly regulate the PI3K/Akt signaling pathway by virtue of the biological advantages of multi-targets， multi-components， and multi-pathways and play an overall protective role in CIRI. By analyzing the related research progress of traditional Chinese medicine in China and abroad in recent years， the authors summarized the role and mechanism of regulating the PI3K/Akt signaling pathway in the prevention and treatment of CIRI， so as to provide further theoretical basis for the study of the mechanism of clinical prevention and treatment of CIRI.

Research progress of the endoplasmic reticulum-mitochondrial interactions in post-stroke cognitive impair-ment / 实用医学杂志

Post-stroke cognitive impairment(PSCI),refers to a range of clinical syndromes of cognitive impairment caused by stroke.Although its specific pathogenesis is still unclear,many studies have confirmed that endoplasmic reticulum-mitochondria interaction has become a key hub for intracellular signal transduction and substance metabolism,and its regulation of various biological processes,such as Ca2+ balance,lipid metabolism,mitochondrial dynamics,autophagy,and neuroinflammation,is closely related to the development of PSCI.There-fore,in this paper,we will review the various functions of endoplasmic reticulum-mitochondrial interactions and explore their specific roles in PSCI,in order to discover new therapeutic targets and provide new theoretical basis and references for the development of PSCI-targeted drugs in the future.

Comparison of clinical outcomes in patients with 4b acute myocardial infarction caused by early and late stent thrombosis / 天津医药

Objective To observe and compare in-hospital and 1-year survival and prognosis of patients with 4b acute myocardial infarction(AMI)caused by early and late stent thrombosis(ST).Methods A total of 302 patients with 4b acute myocardial infarction caused by ST were enrolled in this study from January 2015 to February 2018.ST patients were confirmed by coronary angiography.These patients were divided into two groups:the early ST group(n=26)and the late ST group(n=276)according to the time of ST occurrence.Endpoint events during hospitalization and one year of follow up were compared between the two groups of patients.The primary endpoint events included cardiac death and recurrent AMI.The secondary endpoint events included target lesion revascularization(TLR),re-stent thrombosis,heart failure and stroke.The incidence of no endpoint events was compared between two groups of patients by Kaplan and Meier survival analysis.Cox regression analysis was used to analyze risk factors for endpoint events in patients with type 4b AMI.Results There was no significant difference in the incidence of the primary endpoint events during hospitalization between the two groups(7.7%vs.3.3%,P=0.243).The incidence of heart failure was higher in the early ST group than that of the late ST group(11.5%vs.1.4%,P=0.016).There was no significant difference in the incidence rates of other secondary endpoint events between the two groups(P＞0.05).After a mean follow-up of 1 year,the incidence rates of primary endpoint events and the secondary eendpoint events were higher in the early ST group(20.0%vs.5.9%,P＜0.05 and 36.0%vs.11.5%,P＜0.01)than that of the late ST group.Kaplan and Meier survival analysis showed that the 1-year cumulative incidences of non-primary(P= 0.022)and non-secondary events(P＜0.001)were lower in the early ST group than those of the late ST group.Cox regression analysis showed that hypertension and history of coronary artery bypass grafting were independent risk factors for primary endpoint events in patients with 4b AMI,and intraoperative implantation of intraaortic balloon pump(IABP)and shortening the time from stent thrombosis to balloon dilation(ST to B)were independent protective factor.Conclusion Early ST patients have similar in-hospital outcomes and poor long-term prognosis compared with late ST induced 4b type AMI patients.Intraoperative implantation of IABP and shortening of ST to B time may improve the prognosis of 4b type AMI patients.

Validity and reliability of the Chinese version of the Body Acceptance by Others Scale-2 in adults / 中国心理卫生杂志

Objective:To examine the validity and reliability of the Chinese version of the Body Acceptance by Others Scale-2(BAOS-2)in adults.Methods:Totally 616 adults(aged 18-56 years)were selected to test the structural validity,and internal consistency reliability of the scale.The Body Appreciation Scale-2(BAS-2),Func-tionality Appreciation Scale(FAS),Self-Compassion Scale(SCS),Self-Esteem Scale(SES)and Satisfaction with Life Scale(SWLS)were used as criteria to test criterion validity.A sample of 55 adults was retested 2 weeks later for the test-retest reliability.Results:The exploratory factor analysis extracted one factor,and the factor loading range of each item was 0.59-0.76.The confirmatory factor analysis showed that the factor model fit indices were acceptable(x2/df=2.99,CFI=0.91,GFI=0.90,TLI=0.89,RMR=0.04,RMSEA=0.08).The scores of the Chinese version of BAOS-2 were positively correlated with the scores of BAS-2,FAS,SCS,SES and SWLS(r=0.43-0.66,Ps＜0.001).The Cronbach a of the Chinese version of BAOS-2 was 0.90,and the test-retest reliabili-ty(ICC)was 0.65.Conclusion:The Chinese version of the Body Acceptance by Others Scale-2(BAOS-2)has i-deal validity and reliability.

Moral Dilemma and Research on Coping Style of Frontline Nurses During the Outbreak of COVID -19 / 中国医学伦理学

【Objective:】 To understand the moral dilemma, coping style of frontline nurses and their correlation during the COVID -19. 【Methods:】 From March to April, 2021, 651 nurses working in designated hospitals for COVID -19 were selected by convenient sampling, and the Chinese version of Moral Distress Scale-Revised (MDS-R) and Chinese version of Coping Style Questionnaire (CSQ) were used for investigation. 【Results:】 Frontline nurses’ MDS-R score was 91.0, "value conflicts" was the moral dilemma with the highest frequency and intensity, more than half (51.0%) of the respondents had considered leaving their position because of moral dilemma. "Problem solving" and "seeking for help" were the major coping strategies adopted by the nurses. Nurses who directly provide medical services for COVID -19 patients, dissatisfied with hospital-related training and adopted negative coping strategies had higher moral dilemmas than other nurses. 【Conclusion:】 The moral dilemma of frontline nurses is at a high level during the period of epidemic prevention and control. Nursing managers should pay attention to guiding and helping nurses to establish positive coping styles and improve their ability to respond to major public health emergencies.