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BACKGROUND: Artificial femoral head replacement is an effective method for the treatment of elderly unstable intertrochanteric fractures. However, the effect of lesser trochanter reconstruction in femoral head replacement for Evans-III femoral intertrochanteric fractures has not been reported. OBJECTIVE: To analyze the effect of lesser trochanter reconstruction on the outcome of artificial femoral head replacement with long stem in elderly patients with Evans-III femoral intertrochanteric fracture. METHODS: A retrospective analysis was performed on medical records of 45 elderly patients who underwent bipolar long-stem artificial femoral head replacement due to Evans-III femoral intertrochanteric fractures in the Department of Bone and Joint Surgery, Second Affiliated Hospital of Xi’an Jiaotong University from June 2017 to May 2021. According to whether the small trochanter was reconstructed during surgery (reduction and fixation), they were divided into the reconstruction group (n=25) and the non-reconstruction group (n=20). The operation time, bleeding volume, time of getting out of bed, hospital stay time, Harris scores at 3 and 6 months postoperatively, and the incidence of complications during follow-up were compared between the two groups. RESULTS AND CONCLUSION: (1) The operation time of the reconstruction group was longer (99.72±13.41 minutes) than that of the non-reconstruction group (88.90±16.53 minutes) (t=2.369, P=0.023), and there were no significant differences in bleeding volume, time of getting out of bed or hospital stay time between the two groups (P > 0.05). (2) The Harris score of the reconstruction group (69.06±5.64 points) was higher than that of the non-reconstruction group (63.35±5.93 points) at 3 months postoperatively (t=2.982, P=0.005). At 6 months postoperatively, the Harris score of the reconstruction group (86.67±4.49 points) was higher than that of the non-reconstruction group (82.34±5.68 points) (t=2.782, P=0.009). (3) In addition, no significant difference existed in the incidence of complications between the reconstruction and non-reconstruction groups (χ²=0.008, P=0.927). (4) It is concluded that in elderly patients with Evans-III femoral intertrochanteric fractures, lesser trochanter reconstruction in the artificial femoral head replacement significantly improved postoperative hip function despite increased operative time, demonstrating the importance of the lesser trochanter reconstruction in the artificial femoral head replacement for Evans-III intertrochanteric fractures in the elderly people. [ABSTRACT FROM AUTHOR]

Objectives: The Ripley' s K-function has been widely applied to test for spatial point patterns in many fields such as economic geography, plant geography, and epidemiology. Because of the mathematical confusion of spatial point processes, there are many errors in measuring the distributions of spatial point objects in the corresponding published papers. Methods: This paper discusses Monte Carlo simulation method in the application of Ripley's K-function from perspectives of dynamics of random point patterns, suitability of parameter definition, and reliability of edge correction algorithms. First, we introduce the estimation methods of spatial point pattern analysis based on Ripley's K-function. Second, the formula of Ripley's Kfunction is corrected by various edge effect correction methods and compared in the applications. Finally, the modified algorithm is employed for spatial point pattern analysis of the nutrient concentrations of orange plants in Xinping County, Yunnan Province, China. Results: The preliminary results indicated that the number of Monte Carlo simulations has a great influence on the analysis of the observed spatial point patterns. The significance tests of the observed spatial point patterns change in the process of running ArcGIS Ripley's K-function software package, showing some degree of uncertainty of the observed results. The edge effect correction of Ripley's K-function based on GIS techniques is greatly recommended due to its extension to an arbitrary polygon from a common rectangular shape. Conclusions: Considering the popularity of Monte Carlo simulation in statistics and spatial data analysis, this paper provides important insights on edge correction and significance tests in other spatial clustering methods. [ABSTRACT FROM AUTHOR]

Unmanned aerial vehicles (UAVs) have been one of the most important remote sensing monitoring tools for precision agriculture in recent years, due to their small size, light weight, and flexible flight control. However, the overall brightness of the UAV multispectral image is relatively low except for the reflection parts, resulting in uneven radiation between the images. The reason can be the strong reflection of some ground objects, such as water and stainless steel. It is likely to pose a serious impact on the subsequent application of UAV multi-spectral images in the precise monitoring of crop growth, quality, pests, and diseases. In this study, a radiation consistency correction was performed on the low-altitude airborne high-resolution UAVs multi-spectral remote sensing images that were collected from the detection of nutrient element levels in the citrus canopy, with an emphasis on the images of the same flight that caused by strong reflections of water bodies. Several types of relative correction (also referred to as radiometric normalization) have been widely used for the radiometric consistency correction between remote sensing images at present, such as Histogram matching, Pseudo invariant Features, and Statistic regression. Specifically, the fast and simple Histogram matching only considered the brightness difference between the images, resulting in the loss of image gray levels and distortion of the overall gray distribution. As such, the radiation characteristics of the ground objects were also missing in the original image. In Pseudo invariant Features and Statistic regression, the image statistics and manual selection of samples were adopted to establish sample sets, further to automatically select a sample set for a radiation correction model. These radiation consistency corrections were suitable for the same flight caused by the intensity of illumination. However, a sufficient high-quality sample set cannot be manually selected, due to the low visualization, average brightness, and overall image contrast, particularly for the low-illuminance image caused by the reflection of ground objects. Therefore, a radiant consistency correction was proposed for these UAVs’ multispectral images. First, the specific parameters of radiation correction were calculated, according to the calibration cloth. Secondly, a radial vignetting and compensation model was used to suppress the Dark-corner phenomenon in images. Then, the histogram contrast stretching was performed on the low-illuminance images to obtain enough feature points during the feature detection. Subsequently, the scale-invariant feature transform (SIFT) was employed to extract and match the feature points of the reference image and the image to be corrected. After that, a correction model was constructed using the random sample consensus (RANSAC) to correct the image, according to the digital number value (DN) of homologous points, where bilateral filtering was performed to remove the noise. Finally, the DN value of the image was converted into the reflectance represented by the parameters of radiation correction. The evaluation indicators were selected as the mean absolute errors (MAEs) of the Blue, Green, Red, RedEdge, NIR channels, and the Green Normalized Difference Vegetation Index (GNDVI) of 15 citrus trees in the overlapping area of adjacent images, in order to verify the accuracy of the correction. The test results show that the new radiation consistency correction presented a higher accuracy than the histogram matching. The MAEs of the Blue, Green, Red, RedEdge and NIR channels after correction were 0.2%, 0.5%, 0.6%, 1.7%, and 1.2%, respectively. The GNDVI MAEs was 0.3%. Consequently, the spectral distortion can be relieved to effectively improve the utilization of remote sensing images caused by water reflections. The finding can also provide an accurate dataset for the subsequent quantitative research. Some challenges have still remained: 1)The highlights are needed to be removed in the reflection areas, such as water bodies. 2) There are also some reflective objects except water, such as stainless steel and glass. Anyway, the new radiation consistency correction can be extended to the more strong reflection in the application of UAV multi-spectral images in precision agriculture. [ABSTRACT FROM AUTHOR]

近年来,医学影像学发展迅速,在临床诊断中的地位日渐重要。医学影像学实习是将枯燥的理论知识加以灵活运用的重要培训阶段,为了提高实习的教学质量,需要建立一种与时俱进的新的教学模式。将以案例为基础的学习（CBL）与多媒体教学相结合运用于医学影像学实习教学中,可以将枯燥的教学变得直观生动,打破传统单一的教学模式,加强实习教学的效果。不但能促进学生对知识点的理解和掌握,还可以激发学生的学习兴趣,提高学生学习的主动性,锻炼学生的综合分析、归纳总结等多方面的能力,增强对所学知识的横向联系,对医学生进入未来的临床工作打下良好的基础。 [ABSTRACT FROM AUTHOR]

BACKGROUND: Understanding the characteristics of bacteriology in periprosthetic joint infection and choosing specific anti-infective drugs are very important to control the periprosthetic joint infection. The results of bacterial culture and antimicrobial susceptibility test can provide important reference for diagnosis and treatment. OBJECTIVE: To investigate the distribution and drug resistance of pathogenic bacteria in periprosthetic joint infection patients, and analyze the effect of bacterial culture results on the treatment period. METHODS: A retrospective analysis was conducted on 59 patients who underwent artificial joint revision between September 2015 and September 2019. The infection time, results of bacterial culture and antimicrobial susceptibility test, antibiotics application duration, prosthesis-free interval, total length of hospital stay from infection to renovation, recovery time of erythrocyte sedimentation rate and C-reactive protein were collected. The pathogenic bacteria distribution, drug resistance situation and the effect of the pathogenic bacteria and bacterial resistance on antibiotics application duration, prosthesis-free interval, and days in hospital were analyzed. RESULTS AND CONCLUSION: (1) Among the 59 patients with periprosthetic joint infection, there were 31 cases of hip joint and 28 cases of knee joint. The highest proportion of periprosthetic joint infection phase was delayed infection (49%). The pathogenic bacteria were cultured from 35 cases, and the positive rate of bacterial culture was 59%. (2) Among the cultured pathogens, staphylococcus aureus accounted for the highest proportion (29%). (3) The pathogenic bacteria of 18 patients were antibiotic resistant, and the drug resistance rate reached 51%. (4) The bacterial cultured negative group had longer prosthesis-free interval and longer recovery times of erythrocyte sedimentation rate and C-reactive protein than those of the positive group (P < 0.05). (5) Compared with the group with sensitive antibiotics, the duration of antibiotic application and recovery times of erythrocyte sedimentation rate and C-reactive protein were longer in the group with resistant antibiotics (P < 0.05). (6) In this study, the positive rate of bacterial culture in periprosthetic joint infection patients was not high, but the resistance rate of pathogenic bacteria was relatively high; the treatment period with positive pathogenic bacteria and sensitive antibiotics was shorter. [ABSTRACT FROM AUTHOR]