Quadrant Method Research Articles

Location of the Anatomic Footprint Centers of the Anterior Cruciate Ligament Determined by Quadrant Method on Three-Dimensional Magnetic Resonance Imaging.

The quadrant method is widely used to determine the femoral footprint center (FFC) on radiographs or computed tomography (CT) and can also describe the tibial footprint center (TFC). However, its application on three-dimensional (3D) magnetic resonance imaging (MRI) has been limited. This study aims to describe the ACL footprint center position on 3D MRI of healthy knees using the quadrant method. Proton density (PD) sequence 3D MRI was conducted on 45 intact knees, aged 18 to 45years. The centers of the ACL footprints were determined, and 2D simulated radiographic images were generated from the 3D MRI data. The quadrant method was then applied to calculate the positions of the footprint centers. The FFC was located at 31.6% in the deep-shallow (DS) direction and 31.3% in the high-low (HL) direction. The TFC was positioned at 45.1% in the mediolateral (ML) direction and 39.9% in the anteroposterior (AP) direction. The ACL footprint centers identified in this study were positioned similarly to previous studies, with the exception of the TFC in the ML direction, which was found to be more medial. This approach has the potential to enhance preoperative planning and intra-operative navigation in ACL reconstruction surgeries.

Proximally positioned femoral grafts decrease passive anterior tibial subluxation in anterior cruciate ligament reconstruction using a posterior trans-septal portal.

To compare the anterior and posterior trans-septal (TS) portal approaches in anterior cruciate ligament reconstruction (ACLR) by evaluating femoral tunnel positioning and passive anterior tibial subluxation (PATS). A total of 205 patients who underwent primary ACLR using the outside-in technique between March 2018 and December 2021 were retrospectively enrolled. Patients were classified into two groups based on the viewing techniques: the anterior group was treated using anteromedial or anterolateral portals (n = 155), and the TS group was treated using posterior TS portal (n = 55). The relative locations of the femoral tunnel were evaluated using the deep-shallow planes (X-axis) and superior-inferior planes (Y-axis) with the quadrant method in the lateral femoral condyle on a 3-dimensional computed tomography image. Anterior tibial subluxation for the lateral and medial compartments relative to the femoral condyles was evaluated as measured on magnetic resonance imaging. Knee laxity was assessed using the pivot-shift test and stress radiography. In the posterior TS group, the femoral tunnel was usually located deeper on the X-axis and more superior on the Y-axis, which corresponds to a more proximal position, than in the anterior group (deeper on the X-axis and superior on the Y-axis). Moreover, the femoral tunnel locations in this group were more compactly distributed than those in the anterior group. The TS group showed significantly better reduction of postoperative PATS in the lateral compartments than the anterior group (anterior group vs. TS group: lateral compartment, 3.2 ± 3.1 vs. 4.5 ± 3.2mm; p = .016). Significantly better results were found in the TS group for knee stability as assessed by the pivot-shift grade (p = .044); however, there were no significant differences between the two groups with respect to patient-reported outcome measures (p > .05) and other complications (p = .090). Our results suggest that positioning the femoral tunnel using the posterior TS portal approach may lead to better outcomes in terms of PATS and rotational stability compared to the anterior portal approach in ACLR.

Anatomic femoral tunnel and satisfactory clinical outcomes achieved with the modified transtibial technique in anterior cruciate ligament reconstruction: A systematic review and meta-analysis

BackgroundAnatomic anterior cruciate ligament (ACL) reconstruction is considered the gold standard treatment for ACL injuries because it aims to restore the knee's normal anatomy and stability, while also protecting long-term knee health. Long-term clinical and radiological outcomes after ACL reconstruction using the modified TT technique are unclear. ObjectiveTo assess the clinical and radiological outcomes following ACL reconstruction using modified transtibial (TT) techniques at a minimum 12-month follow-up. DesignA systematic review with meta-analysis. MethodsPubMed, EMBASE, Web of Science, the Cochrane Library, and MEDLINE databases were searched from the inception to December 1, 2022. PICO search strategy was used to identify studies applying modified TT techniques on patients with ACL reconstruction and a minimum follow-up of 12 months. Eligible studies were identified independently by two reviewers. We extracted data on patient demographics, surgical characteristics, patient reported outcomes including subjective evaluations and clinical outcomes. Radiological data including femoral and tibial tunnel position, femoral and tibial tunnel length, and femoral tunnel angle were also extracted. The tunnel position was evaluated using the quadrant method based on three-dimensional computed tomography (3D CT) images. The standardized mean difference (SMD) and 95 % confidence interval (CI) were calculated for clinical and radiological outcomes. ResultsSixteen studies involving 628 patients were finally included. The SMD of Lysholm (90.39; 95 % CI 83.41–97.38), IKDC (86.07; 95 % CI 79.84–92.31), and Tegner (6.15; 95 % CI 3.96–8.33) scores were considered satisfactory. The depth of the femoral tunnel showed a pooled SMD of 30.08 % (95 % CI 28.25–31.91 %), and the height showed a pooled SMD of 37.72 % (95 % CI 35.75–39.70 %). The pooled SMD for the femoral tunnel angle in the coronal plane was 48.27°(95 % CI 43.14–53.40°), and the pooled SMD for the femoral tunnel length was 33.98 mm (95 % CI 29.03–38.93 mm). ConclusionsThis investigation has shown that modified TT technique can create an anatomic femoral tunnel and maintain optimal tunnel length and angulation. Most patients had satisfactory subjective outcomes and physical examinations after ACL reconstruction using modified TT technique. This information may assist in guiding expectations of clinicians and patients following ACL reconstruction with modified TT technique.

Comparison of the quadrant method measuring four points and bernard method in femoral tunnel position evaluation on 3-dimensional reconstructed computed tomography after anatomical single-bundle anterior cruciate ligament reconstruction

PurposeThis prospective study aimed to compare the postoperative evaluation of the quadrant method measuring four points and Bernard method in femoral tunnel position evaluation on 3-Dimensional (3D) reconstructed computed tomography (CT) following the arthroscopic single-bundle anterior cruciate ligament (ACL) reconstruction.MethodsThirty-eight patients with ACL tears that were reconstructed using single-bundle ACL reconstruction between May 2021 and March 2023 were included in this study. Postoperative 3D CT images were obtained after the operation. The femoral tunnel position was measured by use of the quadrant method measuring four points and Bernard method.ResultsAverage mean position of the femoral tunnel insertion center on the 3D CT image was at 26.16 ± 6.27% in the x-coordinate and at 24.36 ± 5.52% in the y-coordinate according to the Bernard method. Meanwhile, the position of the femoral insertion of the ACL measured by the quadrant method measuring four points was 24.2% ± 6.86% in the x-coordinate and 21.16% ± 5.14% in the y-coordinate.ConclusionsBoth the quadrant method measuring four points and Bernard method were effective in femoral tunnel position evaluation on 3D reconstructed CT. Application of the quadrant method measuring four points on 3D CT showed the advantage that measurement can be taken regardless of the shape of the bone tunnel.

Research on the Optimization of Digital Transformation of Social Assistance Based on Entropy Change Theory

With the development of digitalization in China, the social assistance environment has also undergone tremendous changes in the digital era, which requires social managers to achieve high-quality and efficient assistance through digital transformation. The research introduces the theory of entropy change, constructs a two-dimensional quadrant method, and demonstrates that the orderly digital transformation of social assistance is achieved by negative entropy reduction offsetting positive entropy increase. Based on the current situation and case study of the digital transformation of social assistance in China, the entropy change of social assistance system has the characteristics of variability, uncertainty and complexity. Based on these three characteristics, the optimization path of the digital transformation of the social assistance system is proposed from the perspectives of negative entropy increase and positive entropy flow.

A comparative study on 3D printing-assisted arthroscopic IDEAL point femoral tunnel positioning for anterior cruciate ligament reconstruction versus conventional arthroscopic positioning

BackgroundThis study aimed to investigate the feasibility and precision of using a 3D-printed template for femoral tunnel placement in guiding the optimal positioning of the Internal anatomical stop and Low tension maintenance (IDEAL) bone tunnel during single-bundle anterior cruciate ligament (ACL) reconstruction.MethodsA retrospective analysis was conducted on 40 patients who underwent arthroscopic single-bundle ACL reconstruction at our hospital between April 2021 and November 2021. In the direct vision group, the IDEAL bone tunnel was positioned using radiofrequency localization directly visualized at the stump. In the 3D-printed positioning group, preoperative CT scans and Digital Imaging and Communications in Medicine (DICOM) data were employed. Following the Quadrant method by Bernard, the femoral tunnel’s depth was set at 25% and its height at 29%. Postoperative plain CT scans enabled the reconstruction of 3D models for both groups. The accuracy of femoral tunnel placement was then compared.ResultsThe central locations of the bone tunnels in the direct vision group were at a mean depth of 25.74 ± 1.84% and a height of 29.22 ± 2.97%. In the 3D printing localization group, these values were 25.39 ± 2.98% for depth and 28.89 ± 2.50% for height, respectively. No significant differences were found in tunnel positioning between the groups. Both groups demonstrated statistically significant improvements in International Knee Documentation Committee Subjective Knee Form (IKDC) and Lysholm scores postoperatively, with no significant differences observed 12 months post-surgery.ConclusionThe findings of this study suggest that 3D printing-assisted arthroscopic IDEAL point femoral tunnel positioning and conventional arthroscopic positioning are feasible and effective for ACL reconstruction. Using 3D printing technology to design femoral anchor points in ACL reconstruction allows for the customization of anterior fork reconstruction and precise bone tunnel positioning, supporting the goal of individualized and accurate reconstruction.

Physical and vegetation characteristics of soil cover on a liquefied land

Liquefaction is a phenomenon where a solid soil becomes liquid due to an earthquake or other vibrations and other sources of intense shaking, leading to a loss of soil strength and stiffness. Liquefaction can damage structures and condition of the land surface and may affect the state of the vegetation that grows on the land. Therefore, it is necessary to study the physical properties of the soil and the condition of vegetation after the liquefaction event. This study examines changes in the physical conditions of alluvial soil and vegetation cover on the land surface after the liquefaction disaster and future management strategies. This research was carried out from August to December 2022 by taking composite and representative soil samples from three land conditions, namely liquefied land consisting of eroded and piled up soil, as well as a control sample from ground that was not liquefied. Soil sample analysis was conducted at the Laboratory of Soil Science, Faculty of Agriculture, Tadulako University. The research used several observational variables: soil texture, permeability, bulk density, porosity, and organic matter. Observation of land surface cover and vegetation types was done using the quadrant method. The results indicated that, overall, areas affected by liquefaction experienced a substantial loss of soil mass, leading to a lower land surface, particularly in regions prone to erosion. Due to the erosion of surface soil, the remaining subsoil had a sandy loam texture, higher bulk density, increased permeability, and reduced organic matter content. As a result, the ground surface became undulating, with mounds of soil and irregular surface drainage in certain areas. For areas that experienced liquefaction up to four years after the disaster, the level of land cover only reached 60-61%. In contrast, the level of land cover by surface vegetation reached 93.7%.

PENGELOLAAN VEGETASI DI KAWASAN EKOWISATA MANGROVE PERANCAK, JEMBRANA

Perancak mangrove forest is one of the important supporters for mangrove ecotourism in perancak as an ecosystem that functions ecologically, economically and socially as an effort to preserve the beach in a sustainable manner. This research aims to determine the level of diversity of mangrove vegetation types in the perancak coastal area and conduct mangrove management efforts through vegetation analysis and soil analysis. Sampling carriedout on true mangroves and associated mangroves using purposive sampling technique. The method of flora sampling was carried out by quadrant method by calculating the important value index, diversity index and type distribution pattern. True mangroves consist of 13 species and 1367 individuals, dominated by rhyzophora stylosa, with a total importance index (indeks nilai penting)= 299.86 % (classified as sestable), diversity index 1.1192 and distribution pattern = 0.548 (vegetation is stable and uniform). Associate mangroves consists of 13 types and 649 individuals, dominated by the type Terminalia cattapa. Important index =297.892 %, diversity index = 0.9438 and type distribution pattern = 0.73 i.e vegetation that grows is classified as uniform. Analysis results for the 5 soil samples for total n, p and k elements available and organic c, all support mangrove growth. the development of true mangroves and associations is the main supporting factor for the development of tourism areas in the perancak jembrana ecotourism area which is now developing into a beach park developed by the people of Perancak village. Keywords: Perancak; Mangrove Diversity; Management; Soil Analysis

Stakeholder Analysis Using The Vectorized Salience Model, Enhanced Power-Interest Grid, And Stakeholder Cube Diagrams

Abstract—Stakeholders are parties affected by a project, with both positive and negative impacts. In a project, the expectations of these stakeholders must be managed properly, and a project manager plays an important role in satisfying and balancing the interests that exist between them. The stakeholder analysis process needs to be carried out in detail. It must also be supported by the right tools so that it can reveal new insights that may have been hidden behind the stakeholder data. In this research, two techniques are proposed to increase the acuity of two tools that are often used in the stakeholder analysis process, namely the salience diagram and the power grid diagram. Improvements were made by using vectorization techniques for salience diagrams and applying Gartner's magic quadrant method to power grid diagrams. Both improvements can show more clearly the position of stakeholders in the categorization formed according to the two tools. Of course, this will further assist the project team in determining the right strategy for each stakeholder so that all elements support the project’s success.

Cluster Mapping of Waste Exposure Using DBSCAN Approach: Study of Spatial Patterns and Potential Distribution in Bantul Regency

High level of plastic waste production is a common issue in various places, including the Special Region of Yogyakarta province. It is proven that the Piyungan Integrated Waste Disposal Site (TPST) or Final Disposal Site (TPA) in Bantul Regency has been closed several times due to capacity exceeding the quota and some blockages from residents around the TPA. Issues related to microplastic contamination resulting from discarded plastic waste are fascinating to study, considering the long-term impact of microplastic contamination on human health. This research aims to map the distribution of locations with the potential for waste accumulation to reduce the negative consequences of microplastic contamination. The population used included TPS and markets in Bantul District, with the sample being the distribution of TPS and market points in Bantul District in 2023. The results of checking the point distribution pattern using the quadrant and nearest neighbor method showed that the distribution of waste accumulation points had a clustered design; thus, it could be continued with cluster analysis using the Density-Based Spatial Clustering of Applications with Noise (DBSCAN) method. Meanwhile, the number of clusters was determined iteratively from a combination of DBSCAN parameters (MinPts and Epsilon). The best method was evaluated based on the Silhouette Coefficient (SC) value, which in this case was 0.78 (MinPts 7 and Eps 1500) and included in the strong category. Subsequently, exploration was carried out by reducing the MinPts value and the lowest limit value of strong SC.

App-based analysis of the femoral tunnel position in ACL reconstruction using the quadrant method.

The purpose of this study was to examine the intra- and interobserver variability of an app-based analysis of the femoral tunnel position using the quadrant method in primary anterior cruciate ligament reconstruction. Between 12/2020 und 12/2021 50 patients who underwent primary anterior cruciate ligament reconstruction were included in this retrospective study. Intraoperative strictly lateral fluoroscopic images of the knee with marked femoral tunnel were analyzed by four observers using the quadrant method. For retest reliability analysis, measurements were repeated once by 2 observers after 4 weeks. The femoral tunnel position of all included patients averaged 27.86% in the depth relation and 15.61% in the height relation. Statistical analysis showed an almost perfect intra- and interobserver reliability in the depth and height relation. The ICC was 0.92 in the depth relation and 0.84 in the height relation. The Pearson's correlation coefficient in the depth and height relation of observer 1 (0.94/0.81) was only slightly different from the Pearson's correlation coefficient of observer 2 (0.92/0.85). The app-based tunnel analysis took on average 59 ± 16s per measurement. The femoral tunnel analysis with the app-based quadrant method has an almost perfect intra- and interobserver reliability. By smartphone camera, a fast and highly accurate, if necessary also intraoperative, control of the tunnel position can be performed. Level 3-diagnostic retrospective cohort study.

Sustainable integrated solid waste management for a university campus − A case study of the Federal University of Technology Akure (FUTA), Nigeria

This study provides valuable insights into the waste composition, generation rates, and opportunities for improving the current solid management practices of a university campus in Sub-Saharan Africa. Representative points were selected within the campus to collect solid waste (SW). The SW were sampled following ASTM D5231-92. The quadrant method prescribed by ASTM D 6323 was used to reduce about 150 kg of collected waste to 50 kg. The SW samples were collected in triplicates and sorted manually to determine their composition. QGIS, a geographic information system was utilized to optimize waste collection efficiency, optimal collection points, and the number of waste bins. The average daily solid waste generation at FUTA was 952.3 kg, with polythene and paper waste constituting the largest proportions at 26 % and 24 %, respectively. The waste generation rate per capita was estimated at 0.046 kg per day. Remarkably, 81 % of the waste generated at FUTA has the potential for recycling. This offers a viable potential for promoting sustainable integrated solid waste management (SISWM). The study proposes optimising waste collection points from the initial 42 to 97, considering the proximity to buildings and transportation routes. The study did not consider fluctuations in waste generation rates and composition throughout the seasons, yet the data gathered is considered adequate for this initial survey. Lack of collaboration, adequate policies, funds, infrastructure, and political will are among the impediments to SISWM in FUTA. The introduction of colour-coded waste separation bins, and assigning different colours to specific waste types, can promote proper waste disposal and facilitate recycling. Also, engaging the university community through workshops and seminars can foster such behavioural change. Collaboration with local entrepreneurs and recycling centres is another essential aspect of this paradigm shift. Such partnerships can explore innovative solutions for upcycling polythene waste and create waste-to-wealth pathways. Initial challenges of an insufficient policy framework for university- small scale enterprises (SME) engagement and the lack of business growth models could be addressed by promoting relevant skill development and motivational tasking of the existing entrepreneurship faculty. By implementing the proposed strategies and embracing circular economy (CE) principles, FUTA can reduce its environmental impact, promote recycling, and foster a culture of sustainability and entrepreneurial value creation on campus and beyond.

Balancing the development and carbon emissions in rural areas of China

Synergy relationship between human development and carbon emissions in rural areas is an important aspect of Sustainable Development Goals (SDGs). Chinese government is promoting a rural revitalization strategy towards 2050, but whether the development of rural industries and changes in farmers’ lifestyles will increase carbon emissions is a matter of concern. Here, this study obtained survey data from 322 villages of 27 provinces in China by face-to-face interviews, and the reliability of these data has been proven through T-test. Rural Human Development Index (RHDI) and rural carbon emissions have been evaluated, and “quadrant method” was conducted to clarify the relationship between RHDI and rural carbon emissions. Then, this study explored drivers of rural carbon emissions under the different kinds of villages. Results showed that the range of RHDI was 0.166–0.846, and 63.66% villages were at the low level. The average rural carbon emissions were up to 3.15E+03 t CO2 eq, and 28.26% villages were at the high level. However, villages with low RHDI and low carbon emissions accounted for the highest proportion (47.52%), and the increase of RHDI significantly caused more carbon emissions. 73.73% of carbon emissions came from people living, in which diesel of transportation and electricity were the main sources of rural carbon emissions, and the increase of population and area can significantly bring about more carbon emissions. Overall, the development level of Chinese rural area was relatively low, and the use of clean energy needs to be further optimized to arrive the goal of decoupling of economy and carbon emissions.

Research progress of femoral bone tunnel positioning in anterior cruciate ligament reconstruction

To review the concept and methods of femoral bone tunnel positioning in anterior cruciate ligament (ACL) reconstruction, in order to provide a reference for clinical treatment. The relevant literature on the concept and methods of femoral bone tunnel positioning in ACL reconstruction in domestic and international research was extensively reviewed. The position of the femoral bone tunnel is a key factor in determining the prognosis of ACL reconstruction. The concept of femoral bone tunnel positioning in ACL reconstruction has experienced isometric reconstruction, anatomical reconstruction, Ribbon-like theory, I.D.E.A.L. theory, and nearly isometric reconstruction theory. The femoral bone tunnel positioning technique is also changing with the in-depth study of the anatomy and biomechanics of the ACL, and each bone tunnel positioning technique has its own advantages and disadvantages. Over-The-Top technique is now mainly used for ACL revision; the clock-face positioning method is basically no longer applicable due to the large error, poor stability, and low retrievability; the bone landmarks positioning method (the lateral condyle of the femur's Resident's ridge and bifurcation ridge, and the the apex of the deep cartilage), which is now mostly used clinically due to the more constant anatomical landmarks. The quadrant method under X-ray fluoroscopy is more cumbersome to implement intraoperatively, so it is mainly used for academic research; computer navigation-assisted positioning has gradually become popular in recent years, which is highly accurate, avoids the influence of human factors on the positioning of the bone tunnel, and has a very good prospect of application; three-dimensional printing-assisted positioning technology, which is accurate in positioning, with a high degree of reproducibility and a short learning curve. The concept of femoral bone tunnel positioning for ACL reconstruction has undergone several evolutions, reflecting the deepening of the understanding of ACL and the improvement of the clinical results of reconstruction. The precision, personalization, and intelligence of positioning techniques are the focus of current and future development.

Bone Density Distribution Pattern in the Lateral Wall of the Femoral Intercondylar Notch: Implications for the Direct Insertion of the Femoral ACL Attachment

Background: The ideal position of the femoral bone tunnel in the anterior cruciate ligament (ACL) is controversial. The functional importance of the ACL fiber varies depending on where it is attached to the femur. Functionally important fibers can cause high mechanical stress on the bone, and the Wolff law predicts that bone mineral density will increase at high mechanical stress sites. Purpose/Hypothesis: The purpose of this study was to use computed tomography imaging to determine the distribution pattern of bone density in the lateral intercondylar wall. It was hypothesized that the high-density area (HDA) of the lateral intercondylar wall would reflect the functional insertion of the ACL as reported in previous anatomic studies. Study Design: Descriptive epidemiology study. Methods: Data from 39 knees without ACL injuries were retrospectively collected. The HDA of the lateral intercondylar wall was defined as the region containing the top 10% of the radiodensity values. The shape of the HDA was approximated as an ellipse, and the quadrant method was used to determine the center of the ellipse. The association between the ratio of the minor axis to the major axis of the ellipse and background characteristics was investigated. Results: According to the quadrant method, the center of the HDA ellipse was 33.6% in the deep-shallow direction and 23.4% in the high-low direction. The center of the ellipse was comparable to the anatomic center of the ACL footprint, as previously reported. The ratio of the minor axis to the major axis of the ellipse was 0.58 (95% CI, 0.54-0.62). There was a significant negative correlation between the ratio of the minor axis to the major axis of the HDA ellipse and the posterior tibial slope ( r = −0.38, P = .02). Conclusion: The center of the HDA ellipse was found to be similar to the anatomic center of the ACL footprint. Considering the mechanical stress responses in bone, the HDA of the lateral intercondylar wall has the potential to represent the ACL insertion, especially functional insertion.

Studying Floristic Composition for the Conservation of Parque das Camélias (Braga Municipality) Biodiversity

The conservation of biodiversity and the understanding of its distribution patterns play a crucial role in promoting effective land management. The present study aimed to identify herbaceous species in Parque Urbano das Camélias located in the city of Braga. The research was conducted as part of an ongoing collaboration between the School of Sciences at the University of Minho and the Municipal Council of Braga. The site was sampled using the quadrant method, employing a 1m2 measurement, to encompass 12 strategically selected locations throughout the park. The findings encompassed 28 distinct specimens, with identification achieved at the genus level for 27 and at the species level for 25. The study area harbors both native species from mainland Portugal and exotic species, with the Poaceae family being predominant, accounting for 50% of the identified individuals. Some of the species identified in the park include Avena spp., Bromus madritensis, and Plantago lanceolata. The study discusses preservation strategies and biodiversity enhancement for the Parque Urbano das Camélias.

Vegetation–edaphic correlation and importance value index in himalayan ‘ecotone’ temperate conifer forest using the multivariate technique

Himalayan ‘Ecotone’ temperate conifer forest is the cradle of life for human survival and wildlife existence. In spite of the importance of these areas, they have not been studied in depth. This study aimed to quantify the floristic structure, important value index (IVI), topographic and edaphic variables between 2019 and 2020 utilizing circular quadrant method (10 m x 10 m). The upper-storey layer consisted of 17 tree species belongs to 12 families and 9 orders. Middle-storey shrubs comprised of 23 species representing 14 families and 12 orders. A total of 43 species of herbs, grasses, and ferns were identified from the ground-storey layer, representing 25 families and 21 orders. Upper-storey vegetation structure was dominated by Pinus roxburghii (22.45 %) and middle-storey by Dodonaea viscosa (7.69 %). However, the ground layer vegetation was diverse in species composition (43 species) and distribution. The floral vegetation structure was encompassing of three floral communities which were diverse in IVI, such as, in Piro–Aial (Group 2), Pinus roxburghii (54.46 x 15.94) had the highest IVI value, followed by Pinus wallichiana (45.21 x 14.85) in Piwa–Quin (Group 3) and Ailanthus altissima (22.84 x 19.25) in Aial–Qugal (Group 1). However, the IVI values for Aesculus indica, Celtis australis, and Quercus incana in Aial–Qugal (Group 1) were not determined due to low detection rate. Nevertheless, eleven of these species showed 0 IVI values in Piro–Aial (Group 2) and Piwa–Quin (Group 3). CCA ordination biplot illustrated the significant differences among floral communities and its distribution, which impacted by temperature, rainfall, soil pH, altitude, and topographic features. Ward's agglomerative clustering finding reflected 'Ecotone' temperate conifer forest is rich and diverse floristic structure.

Fretting fatigue crack nucleation analysis under a variable coefficient of friction

Fretting fatigue is a phenomenon that occurs when two surfaces come into contact and experience oscillatory stresses and displacements of small amplitude. This can lead to a significant reduction in mechanical parts’ lifetime. The complexity of this type of problems relies on the many variables that can affect the results. One of its most important variables is the Coefficient of Friction (CoF), which has been observed to vary throughout a single fretting test. However, this variation is rarely considered in fretting fatigue finite element analyses. In order to analyse the effects of a Variable Coefficient of Friction (VCoF) on nucleation lifetime, a cylinder-on-plane finite element model is developed. To predict nucleation lifetime, two critical plane damage parameters, Fatemi-Socie (FS) and Findley parameter (FP), are used along with an evolving CoF during the first stress cycles. These parameters are evaluated by calculating initiation lifetime where the maximum value of the damage parameter occurs (hotspot method) and by the quadrant averaging method, because of its capability of predicting lifetime with relative accuracy and negative crack angles. To simulate the evolution of the CoF, a Python script that changes the value of CoF before each simulation is developed. This coefficient varies between 0.3633 and 0.65, following arbitrary points on the coefficient’s evolution curve. Once the simulation is concluded, the script evaluates the damage parameters and their equivalent lifetime throughout the contact surface and saves those values in an accumulation parameter that follows Miner’s rule. This process is repeated until CoF reaches its maximum value. The lifetime to nucleation is statistically analysed for all methodologies. The results suggest that, regarding the hotspot method, FP values remain within ± 3 N deviations from the experimental results, while FS results are nearer, within ± 2 N deviations. In addition, the quadrant method results remain at ± 3 N deviations, but providing more accurate results for the FP parameter. The application of a VCoF to these methods leads to less conservative and less deviated results, providing more accuracy for conservative approaches and more consistency for predictions in general. It is concluded that VCoF analysis is an interesting tool to determine more accurately nucleation lifetime for conservative approaches. Additionally, it reduces the predictions variation for differently loaded fretting setups regardless the desired approach.

High flexion femoral side remnant preservation positioning technique: a new method for positioning the femoral tunnel in anterior cruciate ligament reconstruction.

The aim of this study is to find a new method for femoral side preservation positioning in anterior cruciate ligament (ACL) reconstruction and test the accuracy and precision of this method. Fifty patients with isolated ACL rupture (42 males and 8 females) who underwent single-bundle ACL reconstruction in our hospital between July 2022 and July 2023 were included. The lowest point of the cartilage margin of the lateral wall of the intercontinental fossa and the tibial plateau plumb line at 120° of knee flexion were used as the anatomical landmarks for positioning of the femoral tunnel for ACL reconstruction surgery. Femoral side remnant preservation was performed in all cases. Three-dimensional CT was performed 3days postoperatively to collect the data, which were analyzed using Mimics 21.0 software. We measured the posterior cortical distance of the femoral condyle at 90° of knee flexion and the vertical distance from the center of the bone tunnel to the cortical extension line behind the femur. All femoral tunnel positions were marked on a 4 × 4 grid and visualized using the quadrant method. Using the new positioning method in 50 knees, the average distance of x was 25.26 ± 2.76% of t and the average distance of y was 23.69 ± 6.19% of h. This is close to the results of previous studies, where x was 24.2 ± 4.0% of t and the average distance of y was 21.6 ± 5.2% of h. Most femoral tunnel positions were located in the same area. The D values were distributed as follows: 60% in the range of 0 to 2mm, 24% in the range of 2 to 4mm, and 16% more than 4mm. The E values were distributed as follows: 80% in the range of 0 to 4mm and 20% more than 4mm. In arthroscopic ACL reconstruction, the knee was flexed at 120° and the lowest point of the cartilage edge of the lateral wall of the intercondylar fossa and the tibial plateau plumb line were used as anatomical landmarks for the positioning of the femoral bone tunnel, which resulted in more accurate femoral bone tunnel positioning, better reproducibility, and better preservation of the femoral stump compared to traditional positioning methods.

Femoral Tunnel Position in Anatomical Double-bundle ACL Reconstruction is not Affected by Blumensaat's Line Morphology.

The aim of this study was to reveal the influence of the morphological variations of the Blumensaat's line on anteromedial (AM) and posterolateral (PL) femoral tunnel position in anatomical double-bundle anterior cruciate ligament (ACL) reconstruction.Fifty-three subjects undergoing anatomical double-bundle ACL reconstruction were included (29 female, 24 male; median age 27.4 years; range: 14-50 years). Using an inside-out transportal technique, the PL tunnel position was made on a line drawn vertically from the bottommost point of the lateral condyle at 90 degrees of knee flexion, spanning a distance of 5 to 8 mm, to the edge of the joint cartilage. AM tunnel position was made 2 mm distal to the PL tunnel position. Following Iriuchishima's classification, the morphology of the Blumensaat's line was classified into straight and hill (large and small) types. Femoral tunnel position was determined using the quadrant method. A Mann-Whitney U test was performed to compare straight and hill type knees according to AM and PL femoral tunnel position.There were 18 straight and 35 hill type knees (13 small and 22 large hill). AM and PL femoral tunnel position in straight type knees were 21.7 ± 7.0 and 33.6 ± 10.5% in the shallow-deep direction, and 42.1 ± 11.1 and 72.1 ± 8.5% in the high-low direction, respectively. In hill type knees, AM and PL femoral tunnel position were 21.3 ± 5.8 and 36.9 ± 7.1% in the shallow-deep direction, and 44.6 ± 10.7 and 72.1 ± 9.7% in the high-low direction, respectively. No significant difference in AM or PL femoral tunnel position was detected between straight and hill type knees.AM and PL femoral tunnel position in anatomical double-bundle ACL reconstruction was not affected by the morphological variations of the Blumensaat's line. Surgeons do not need to consider Blumensaat's line morphology if AM and PL femoral tunnel position is targeted at the bottommost point of the lateral condyle. This was a level of evidence III study.