Artificial intelligence for detection of intracranial haemorrhage on head computed tomography scans: diagnostic accuracy in Hong Kong.

INTRODUCTION: The use of artificial intelligence (AI) to identify acute intracranial haemorrhage (ICH) on computed tomography (CT) scans may facilitate initial imaging interpretation in the accident and emergency department. However, AI model construction requires a large amount of annotated data for training, and validation with real-world data has been limited. We developed an algorithm using an open-access dataset of CT slices, then assessed its utility in clinical practice by validating its performance on CT scans from our institution. METHODS: Using a publicly available international dataset of >750 000 expert-labelled CT slices, we developed an AI model which determines ICH probability for each CT scan and nominates five potential ICH-positive CT slices for review. We validated the model using retrospective data from 1372 non-contrast head CT scans (84 [6.1%] with ICH) collected at our institution. RESULTS: The model achieved an area under the curve of 0.842 (95% confidence interval=0.791-0.894; P<0.001) for scan-based detection of ICH. A pre-specified probability threshold of ≥50% for the presence of ICH yielded 78.6% accuracy, 73% sensitivity, 79% specificity, 18.6% positive predictive value, and 97.8% negative predictive value. There were 62 true-positive scans and 22 false-negative scans, which could be reduced to six false-negative scans by manual review of model-nominated CT slices. CONCLUSION: Our model exhibited good accuracy in the CT scan-based detection of ICH, considering the low prevalence of ICH in Hong Kong. Model refinement to allow direct localisation of ICH will facilitate the use of AI solutions in clinical practice.

Chest computed tomography analysis of lung sparing morphology: differentiation of COVID-19 pneumonia from influenza pneumonia and bacterial pneumonia using the arched bridge and vacuole signs.

INTRODUCTION: This study evaluated the arched bridge and vacuole signs, which constitute morphological patterns of lung sparing in coronavirus disease 2019 (COVID-19), then examined whether these signs could be used to differentiate COVID-19 pneumonia from influenza pneumonia or bacterial pneumonia. METHODS: In total, 187 patients were included: 66 patients with COVID-19 pneumonia, 50 patients with influenza pneumonia and positive computed tomography findings, and 71 patients with bacterial pneumonia and positive computed tomography findings. Images were independently reviewed by two radiologists. The incidences of the arched bridge sign and/or vacuole sign were compared among the COVID-19 pneumonia, influenza pneumonia, and bacterial pneumonia groups. RESULTS: The arched bridge sign was much more common among patients with COVID-19 pneumonia (42/66, 63.6%) than among patients with influenza pneumonia (4/50, 8.0%; P<0.001) or bacterial pneumonia (4/71, 5.6%; P<0.001). The vacuole sign was also much more common among patients with COVID-19 pneumonia (14/66, 21.2%) than among patients with influenza pneumonia (1/50, 2.0%; P=0.005) or bacterial pneumonia (1/71, 1.4%; P<0.001). The signs occurred together in 11 (16.7%) patients with COVID-19 pneumonia, but they did not occur together in patients with influenza pneumonia or bacterial pneumonia. The arched bridge and vacuole signs predicted COVID-19 pneumonia with respective specificities of 93.4% and 98.4%. CONCLUSION: The arched bridge and vacuole signs are much more common in patients with COVID-19 pneumonia and can help differentiate COVID-19 pneumonia from influenza and bacterial pneumonia.

[Analysis on the current situation and influencing factors of residents' satisfaction with the built environment of China's Hygienic City Initiative].

Objective: To understand the current situation and the main influencing factors of residents' satisfaction with the built environment of China's Hygienic City Initiative. Methods: From the list of China's hygienic cities (excluding county-level cities), 61 cities were randomly selected in equal proportion and the eligible respondents were randomly selected by using the "Questionnaire Star" network platform to carry out the online questionnaire survey. A self-made satisfaction evaluation scale was used to investigate the satisfaction of the included respondents with the urban built environment and search for relevant data on the city level. The two-level multi-factor mixed effect model was constructed to analyze the influencing factors of residents' satisfaction with the built environment of China's Hygienic City Initiative. Results: The age range of 2 465 respondents was mainly between 18 and 40 years old (79.9%), with males being the main group (45.8%). The total score of residents' satisfaction with the built environment of China's hygienic cities was (69.14±13.24) points. Based on four standardized dimensions of sense of gain, the result showed that the satisfaction of urban governance had the highest score (65.08 points), followed by urban environmental sanitation (63.68 points), urban lifestyle (59.97 points) and urban basic function (59.02 points). The analysis results of the two-level multi-factor mixed effect model showed that compared with residents with an annual average concentration of inhalable fine particles in the environment>48 micrograms/cubic meter, residents with an average concentration between 38 and 48 micrograms/cubic meter [ß (95%CI): 1.65 (0.08, 3.21)] and≤37 micrograms/cubic meter or less [ß (95%CI): 1.98 (0.53, 3.43)] had higher satisfaction. Compared with residents whose proportion of the secondary industry to GDP was≤40.9%, residents in cities with a larger proportion had a lower satisfaction level [residents with a proportion of 40.9%-48.03%, ß (95%CI):-2.21 (-3.93, -0.49); residents with a proportion greater than 48.03%, ß (95%CI):-2.58 (-4.58, -0.59)]. Compared with residents with a junior high school or lower education level, residents with a higher education level had a lower satisfaction level [ß (95%CI):-2.37 (-4.57, -0.17)]. Residents of universities and above [ß (95%CI):-3.82 (-6.05, -1.60)], regularly participate in physical exercise [ß (95%CI): 5.78 (4.71, 6.84)] and self-rated good health status [ß (95%CI): 6.39 (5.33, 7.45)] had a higher satisfaction level. Conclusion: The satisfaction of residents with the built environment of China's hygienic cities is still acceptable. Satisfaction is related to individual characteristics such as residents' cultural level, type of residence, frequent participation in physical exercise, and self-rated good health status, as well as urban-level factors such as green coverage rate in built-up areas, annual average concentration of inhalable fine particles, and the proportion of GDP in the secondary industry.

[Prediction on the cardio-cerebrovascular death and probability of premature death caused by common risk factors in China in 2030].

Objective: Predictive models were used to evaluate the impact of common risk factors on the number of cardio-cerebrovascular deaths and the probability of premature death. Methods: Using the data for China estimated by the Global Burden of Disease study 2015 (GBD 2015), we calculated the population attribution fraction (PAF) of risk factors. The proportional change model was used to estimate the number of unattributable deaths by 2030, and to predict the number of deaths, mortality, standardized mortality and probability of premature death by 2030. Results: According to the natural change trend of risk factors from 1990 to 2015, the number of deaths and mortality would reach 6.12 million and 428.53/100 000 by 2030, with an increase of 59.92% and 52.87%. By 2030, the probability of premature death from cardio-cerebrovascular diseases among Chinese aged 30-70 years old would continue to decline, from 11.43% to 11.28% for men, and from 5.79% to 4.43% for women. If the goals of all included risk factors were reached by 2030, 2 289 200 cardio-cerebrovascular deaths would be avoided. If only the exposure to a single risk factor was achieved by 2030, blood pressure, total cholesterol, and fine particulate matter exposure were the three most important factors affecting cardio-cerebrovascular deaths, which would reduce 1 332 800, 609 100 and 306 800 deaths, respectively. Among the involved risk factors, the control of blood pressure would mostly decrease the number of deaths due to ischemic heart disease and hemorrhagic stroke, about 677 300 and 391 100 deaths, accordingly. Conclusion: The control of risk factors is of great significance in reducing deaths and probability of premature death due to cardio-cerebrovascular diseases. If the control targets of all risk factors could be achieved by 2030, the burden of cardio-cerebrovascular diseases would be reduced greatly.

[Diagnosis and treatment for emphysematous pyelonephritis: analysis of 14 cases from a single centre].

Objective: To examine the modalities of treatment and clinical outcomes of emphysematous pyelonephritis (EPN), in order to improve the survival rate of EPN patients. Methods: Totally 14 patients diagnosed as EPN between October 2011 and November 2020 at Department of Urology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine were included in this article. Data collection including patient demographics, clinical manifestations, management and clinical outcomes were conducted by retrospective charts review, after receiving the institutional review board's approval. There were 11 females and 3 males with a median age of 59 years (range: 52 to 73 years). The lesions were located on the left side in 10 patients and right side in 4 patients. All the 14 patients suffered from fever, and present with severe sepsis or septic shock. The median time from symptom onset to admission to hospital was 3 days(range: 2 to 5 days). All cases had diabetes mellitus. Escherichia coli was the most common organism been cultured (11 cases), while Klebsiella pneumonia was the second (3 cases). CT scan showed bubbly or located gas in the renal parenchyma in 5 cases and presence of steaky or mottled gas in the renal parenchyma in 9 cases. All patients had been admitted to ICU for anti-septic shock therapy. Three patients had undergone percutaneous catheter drainage along with broad-spectrum antibiotics therapy while 3 patients had immediate nephrectomy, the other 8 cases had a combination of an initial percutaneous catheter drainage and second stage nephrectomy. Results: In this case series, 3 patients were died from EPN while the other 11 were survived. The median ICU stay time was 6 days (range: 3 to 11 days). Of the 3 patients died from EPN, 2 had undergone percutaneous catheter drainage along and 1 had received immediate nephrectomy. Among the 11 patients who were survived, only 1 had received percutaneous catheter drainage while the other 10 received nephrectomy (8 patients had staged nephrectomy). Follow-up was performed 6 months after discharge. Of the 11 surviving patients, 2 were lost to follow-up, and the remaining 9 patients had an creatine level of (118.4±29.4) µmol/L (range: 89 to 176 µmol/L). Conclusions: For patients coupled with diabetes who were initially diagnosed as acute pyelonephritis, the possibility of EPN should be considered when the disease progressed rapidly especially septic shock occurred. On the basis of empirical broad-spectrum antibiotics therapy and standardized anti-septic shock treatment, a combination of an initial percutaneous catheter drainage and second stage nephrectomy could be efficacious.

[An evidence-based analysis comparing two approaches of robot-assisted laparoscopic radical prostatectomy: the standard technique and Retzius-sparing technique].

Objective: To compare the postoperative outcomes and urinary continence recovery time between standard robotic-assisted laparoscopic radical prostatectomy (RARP) and Retzius-sparing robotic-assisted laparoscopic radical prostatectomy (RsRARP). Methods: A total of 92 patients with low to intermediate-risk prostate cancer who underwent RARP (n=52) and RsRARP (n=40) in Sir Run Run Shaw Hospital from October, 2016 to January, 2018 were retrospectively reviewed. Perioperative data (operative time, estimated blood loss, complications, postoperative staging, postoperative Gleason score) and surgical outcomes (rate of margin positive, urinary continence recovery time) of RARP and RsRARP group were comparatively analyzed. Results: All 92 cases were successfully performed with robot. RARP group had a significantly shorter mean operative time when compared with that in RsRARP group ((103±23) min vs (130±26) min, P<0.05). The two groups had comparable estimated blood loss ((100±54) ml vs (103±64) ml, P>0.05), rate of postoperative infection (5.8% (3/52) vs 5.0% (2/40), P>0.05) and rate of postoperative urine leakage (3.8%(2/52) vs 2.5%(1/40), P>0.05). The two groups had a comparable rate of margin positive (7.7%(4/52) vs 12.5%(5/40), P>0.05). Compared with RsRARP group, the RARP group had a lower rate of urinary continence recovery immediately after the catheter removing at 1 week, 1 month and 3 months after the operation (all P>0.05). The two group had a comparable rate of urinary continence recovery at 6 months after the operation (P>0.05). Conclusion: The RsRARP technique has a good tumor control and obvious advantage of early urinary continence recovery compared with the standard RARP technique. RsRARP technique is safe and effective for the treatment of localized prostate cancer.

[Robot-assisted nephroureterectomy requiring no robot redocking or patient repositioning: experience from a single center with 62 cases].

Objective: To examine a new technique of robot-assisted nephroureterectomy without robot reldocking or patient repositioning. Methods: Patients diagnosed as upper tract urothelial carcinoma treated with this modality between November 2015 and January 2019 at Department of Urology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine were included in this analysis. Data collection including patient demographics, operative procedure and postoperative morbidities were conducted by retrospective charts review, after receiving the institutional review board's approval. There were 35 males and 27 females with a median age of 70 years (range: 30 to 91 years) underwent single docking robot-assisted nephroureterectomy without repositioning. Among the 62 cases, 37 patients had pelvic carcinoma while 25 patients had ureteral carcinoma (with proximal portion 12 cases, middle portion 5 cases and distal portion 8 cases). The patient was placed in a 60 to 80-degree, modified flank position with a 15-degree Trendelenburg tilt. The contralateral arm was positioned perpendicular to the torso on an arm board while the ipsilateral arm was taped to the patient's side with ample padding. The robot cart was then docked at a 90-degree angle, perpendicular to the patient. A "W"-shape, three robotic-arm configurations was used for port placement. Results: The surgical procedures were performed successfully in all the 62 patients. The operation time was (171.6±54.7) minutes (range: 60 to 370 minutes). The estimated blood loss during the operation was 50(50) ml (range: 20 to 400 ml) with 4 patients had transfusion. No perioperative death was encountered. Eleven patients had post-operative complications (Clavien-Dindo grade 2) including 3 cases of hemorrhage and 8 cases of chylous leakage. All cases were regularly followed up with a median time of 37 months (range: 17 to 55 months). There were 8, 30, 19, 4 and 1 case followed up for 48, 36, 24, 18 and less than 18 months, respectively. Three patients had reginal recurrences and 11 cases of distant metastasis occurred, with 5 patients died for cancer. The survival rate within 24 months was estimated as 75.4%(43/57). Conclusion: Robot-assisted nephroureterectomy without robot redocking or patient repositioning could be safely reproduced, with surgical outcomes comparable to other established techniques.

[Quantitative analysis of national hygienic city policies in China from the perspective of policy tools].

Objective: To give some suggestions on the policy optimization of the establishment of National Hygienic City from the perspective of policy system. Methods: Policy documents were searched in WanFang Database and websites of ministries and commissions directly affiliated to the State Council with the key words of hygienic city, and analyzed by using the content analysis and quantitative analysis, based on the theory and perspective of policy tools and the two-dimensional analysis framework. Results: Among the 161 policy documents, supply-based, environment-based, and demand-based policy tools accounted for 6.83% (11/161), 83.85% (135/161), and 9.32% (15/161) respectively. Policy planning, policy implementation, policy supervision, and policy evaluation tools accounted for 10.56% (17/161), 63.35% (102/161), 21.74% (35/161), and 4.35% (7/161) respectively. Conclusion: The government should reduce its dependence on environmental policy tools, especially strategic measures, and attach importance to the use of supply-based policy tools and demand-based policy tools. At the same time, it should pay attention to the formulation of more practical policy tools in the process of policy evaluation.

[Multiple linear regression models with natural logarithmic transformations of variables].

In general, the application conditions of linear regression models could be met after the natural logarithmic transformation of data. From the practical perspective, this paper introduced the linear regression models with natural logarithmic transformation of independent variable, dependent variable, and both independent and dependent variables in detail. The paper illustrated why the equation and coefficients could not be directly explained after the natural logarithmic transformation of data. The percentage changes of X and/or Y were applied to elaborate the principle and method for the explanation of the equation and coefficients. Three examples were used to fit simple linear models with natural logarithmic transformation of independent, dependent, and both independent and dependent variables and the results of theses models were explained in detail.

[Threshold effects of body mass index on the bone mineral density of Chinese rural women in fluorosis area].

To explore the threshold effect of body mass index (BMI) on bone mineral density (BMD) in Chinese women living in the fluorosis area, we conducted a cross-sectional study and recruited 722 women in rural areas in Henan Province, China. After detection and analyses, we found that compared with the normal BMI group, the risk of osteoporosis in the overweight and obese groups were reduced by 32% and 69%, respectively. Threshold effect analysis showed that BMD was positively correlated with BMI when BMI was 16.8-31.2 kg/m2; while when BMI was greater than 31.2 kg/m2, the correlation reached saturation. The correlation observed between low-to-moderate fluoride exposure and BMD in rural women was not significant.

[A pathological report of three COVID-19 cases by minimal invasive autopsies].

Objective: To investigate the pathological characteristics and the clinical significance of novel coronavirus (2019-nCoV)-infected pneumonia (termed by WHO as coronavirus disease 2019, COVID-19). Methods: Minimally invasive autopsies from lung, heart, kidney, spleen, bone marrow, liver, pancreas, stomach, intestine, thyroid and skin were performed on three patients died of novel coronavirus pneumonia in Chongqing, China. Hematoxylin and eosin staining (HE), transmission electron microcopy, and histochemical staining were performed to investigate the pathological changes of indicated organs or tissues. Immunohistochemical staining was conducted to evaluate the infiltration of immune cells as well as the expression of 2019-nCoV proteins. Real time PCR was carried out to detect the RNA of 2019-nCoV. Results: Various damages were observed in the alveolar structure, with minor serous exudation and fibrin exudation. Hyaline membrane formation was observed in some alveoli. The infiltrated immune cells in alveoli were majorly macrophages and monocytes. Moderate multinucleated giant cells, minimal lymphocytes, eosinophils and neutrophils were also observed. Most of infiltrated lymphocytes were CD4-positive T cells. Significant proliferation of type Ⅱ alveolar epithelia and focal desquamation of alveolar epithelia were also indicated. The blood vessels of alveolar septum were congested, edematous and widened, with modest infiltration of monocytes and lymphocytes. Hyaline thrombi were found in a minority of microvessels. Focal hemorrhage in lung tissue, organization of exudates in some alveolar cavities, and pulmonary interstitial fibrosis were observed. Part of the bronchial epithelia were exfoliated. Coronavirus particles in bronchial mucosal epithelia and type Ⅱ alveolar epithelia were observed under electron microscope. Immunohistochemical staining showed that part of the alveolar epithelia and macrophages were positive for 2019-nCoV antigen. Real time PCR analyses identified positive signals for 2019-nCoV nucleic acid. Decreased numbers of lymphocyte, cell degeneration and necrosis were observed in spleen. Furthermore, degeneration and necrosis of parenchymal cells, formation of hyaline thrombus in small vessels, and pathological changes of chronic diseases were observed in other organs and tissues, while no evidence of coronavirus infection was observed in these organs. Conclusions: The lungs from novel coronavirus pneumonia patients manifest significant pathological lesions, including the alveolar exudative inflammation and interstitial inflammation, alveolar epithelium proliferation and hyaline membrane formation. While the 2019-nCoV is mainly distributed in lung, the infection also involves in the damages of heart, vessels, liver, kidney and other organs. Further studies are warranted to investigate the mechanism underlying pathological changes of this disease.

[Overview of logistic regression model analysis and application].

Logistic regression is a kind of multiple regression method to analyze the relationship between a binary outcome or categorical outcome and multiple influencing factors, including multiple logistic regression, conditional logistic regression, polytomous logistic regression, ordinal logistic regression and adjacent categorical logistic regression. This paper illustrates the basic principle, independent variable selection and assignment, applied condition, model evaluation and diagnosis for multiple logistic regression model. Moreover, the principle and application for polytomous logistic regression and ordinal logistic regression models were also introduced. By providing SAS codes and detailed explanations of the result for an example of obesity, readers could be able to better understand logistic regression model, and apply this method correctly to their research and daily work, so as to improve their capacity of the data analysis.

[Overview of multivariate regression model analysis and application].

Analyses of the multivariate regression model are ued very widely in the medical research. Analytical methods of the mutivariate regression model including multiple linear regression, logistic regression, Poisson regression and Cox proportional hazard model were introduced in this article. The contents of the article covered the application conditions of regression models, analytical procedures, strategies of selecting independent variables, extended discussions of regression models and application notes. It is expected that authors could understand the principle of the mutivariate regression model, accurately use these analytical methods in their research, improve the efficiency of data utilization, and enhance the level of statistical analyses.

[An overview of multiple linear regression model and its application].

Multiple Linear Regression (MLR) is a generalization of simple linear regression and is one of the commonly used models in multivariate statistical analysis. This article introduces the MLR model from the perspective of practical application. Four parts, including basic principle, application examples, the application condition and diagnosis, and the extension of the model, are sequentially illustrated in this article. Particularly, in the last part, alternative methods of the model are introduced when the application condition of the model is not met. We sincerely hope that this article could make our audiences have a better understanding of the MLR model in order to improve the efficiency of data utilization and statistical analysis by correctly performing this model in their research.

[The design of interrupted time series and its analytic methods].

Interrupted time series (ITS) is a statistical method for the quasi-experimental design specific to the outcome of time series, in which the effectiveness of an intervening measure is evaluated by examining change in slope and immediate change in level. The key feature of ITS is that the secular trend of time series prior to the intervention can be effectively controlled so as to accurately estimate the intervention effect. The design principle and statistical method for ITS were illustrated by an example of evaluating halving policy for the expert registration fee in the general hospital of a city. The segmented linear regression was used to fit the above time series data and the results were explained in detail. Meanwhile, the study design and model fitting along with explanations of the results with respect to the effects of two types of successive interventions and on different time-points of an intervention were illustrated as well in this paper. The existed upward or downward trend should be taken into account in order to accurately estimate the intervention effect as it exists in most of the public health surveillance data. Two parameters, known as change in slope and immediate change in level, were employed to evaluate the effect of the intervention. The ITS analysis can be widely applied to the program evaluation as it could enrich methods of the evaluation compared to the traditional model of the program evaluation.

Simple template fabrication of porous MnCo2O4 hollow nanocages as high-performance cathode catalysts for rechargeable Li-O2 batteries.

Porous MnCo2O4 hollow nanocages have been fabricated via a simple template method using carbon spheres as a template. The hydrophilic surface of carbon spheres can adsorb Mn(2+) and Co(2+) ions simultaneously to form Mn,Co-adsorbed carbon spheres. The calcination of Mn,Co-adsorbed carbon spheres can result in porous hollow nanocages of MnCo2O4. The MnCo2O4 hollow nanocages are built by nanoscale MnCo2O4 crystals. Because of the unique porous hollow nanostructures, the resulting MnCo2O4/KB cathode shows an efficient electrocatalytic performance in LiTFSI/TEGDME electrolyte-based Li-O2 batteries. The MnCo2O4 hollow nanocages as the cathode catalysts can deliver better performance during the discharge/charge processes and good cycle stability compared with that of the pure KB carbon. The preliminary results manifest that porous MnCo2O4 hollow nanocages are promising high-performance cathode catalysts for Li-O2 batteries. This template technique is a simple, general, low-cost and controllable method and can be extended to prepare other transition metal oxide hollow nanostructures.

High resolution computed tomography and classification of children with interstitial lung diseases.

High resolution computed tomography (HRCT) was used to classify children with interstitial lung diseases (ILD). Sixty children with ILD underwent HRCT in supine position under free-respiratory conditions during scanning. Children under 5 years old were sedated with chloral hydrate and the scanning scope was from the lung apex to the diaphragm. In children older than 5 years old, scans were obtained at three levels: aortic arch, tracheal carina, and 1 cm above the right diaphragm. Five infectious patients were followed up. Two experienced radiologists read the films blindly to observe the type and distribution of ground-glass opacities and bronchovascular bundle abnormalities. Bronchovascular bundles were thick in 49 patients, and were thick and stiff in 27 patients. Of the 41 infectious patients, 39 showed thickened bronchovascular bundles, and 26 showed thick and stiff bronchovascular bundles. Of the 19 non-infectious patients, bronchovascular bundles were thickened in 10 patients, and were thick and stiff in 1 patient. Forty-one patients showed lobular ground-glass opacity (32 infectious, 9 non-infectious). Twenty-seven patients showed both bronchovascular bundle abnormality and lobular ground-glass opacity (20 infectious, 7 non-infectious). Eighteen patients showed patchy or mosaic ground-glass opacity (16 infectious, 2 non-infectious). There were 4 cases of bronchiectasis. HRCT is the first non-invasive diagnostic method for children with ILD, and its different manifestations can be classified. In early manifestation, bronchovascular bundles were abnormal and complicated with lobular ground-glass opacity. Patchy ground-glass opacity was the most common manifestation, and appeared to be difficult to disappear. Bronchiectasis indicated that the disease is irretrievable.

Aerodynamic characteristics of the ventilated design for flapping wing micro air vehicle.

Inspired by superior flight performance of natural flight masters like birds and insects and based on the ventilating flaps that can be opened and closed by the changing air pressure around the wing, a new flapping wing type has been proposed. It is known that the net lift force generated by a solid wing in a flapping cycle is nearly zero. However, for the case of the ventilated wing, results for the net lift force are positive which is due to the effect created by the "ventilation" in reducing negative lift force during the upstroke. The presence of moving flaps can serve as the variable in which, through careful control of the areas, a correlation with the decrease in negative lift can be generated. The corresponding aerodynamic characteristics have been investigated numerically by using different flapping frequencies and forward flight speeds.