In Fused Deposition Modeling (FDM) three-dimensional (3D) printing the printed part is greatly affected by the process parameters, therefore the parameters have to select properly to enhance the ...characteristics of the final product. In view of this, the present paper experimentally and statistically studied the effect of various printing parameters namely build orientation, raster orientation, nozzle diameter, extruder temperature, infill density, shell number, and extruding speed on tensile strength using Polylactic acid (PLA) filament. Based on Taguchi's mixed model fractional factorial design, eighteen experiments were set and the specimens of PLA are printed on an FDM 3D printer and tested for tensile strength using the universal testing machine. Thereafter, the optimal combination of the parameters was selected using Signal-to-Noise ratio (S/N), and Analysis of Variance (ANOVA) is used for indicating the significant parameters and their effect on tensile strength. Moreover, a linear regression model has been developed to predict the tensile strength of the printed part. The results showed that the part strength influenced by the selected process parameters, where only three of them, build orientation (on-edge), nozzle diameter (0.5), and infill density (100%) statistically were significant and highly impact the result. While build orientation has the most influential effect on tensile strength (44.68%). Lastly, the confirmation test showed that there is a good agreement between the experimental and statistical data.
•The paper presents the tensile property for printed parts using FDM 3D printing technology.•Taguchi method utilized to arrange the experiments using mixed model fractional factorial.•Printing parameters analysed by ANOVA to show their impact on tensile properties.
Purpose
To evaluate correlations between preoperative pain sensitivity and postoperative analgesic consumption together with pain perception shortly after arthroscopic partial meniscectomy in ...non-arthritic knees.
Methods
Ninety-nine patients who underwent primary arthroscopic meniscectomy were prospectively divided into three postoperative treatment groups that were prescribed with betamethasone injection (at the end of surgery), oral celecoxib or rescue analgesia (control). Preoperative pain sensitivity was evaluated by pain sensitivity questionnaires (PSQ). Patients were followed for the first three postoperative weeks to evaluate knee injury and osteoarthritis outcome score (KOOS) pain scores and analgesics consumption. Statistical analysis included correlations among preoperative pain sensitivity, postoperative pain levels and analgesics consumption. A receiver operating characteristic curve was plotted to investigate the cutoff values of the PSQ score to predict insufficient postoperative pain reduction.
Results
There were no differences at baseline among all study groups in age, sex, BMI, level of activity, comorbidities and surgical findings. At the final follow-up, KOOS pain scores improved in all groups (
p
< 0.001). Mean final KOOS pain scores were 76.1 ± 15.2 for the betamethasone group, 70.8 ± 12.6 for the celecoxib group and 78.7 ± 11.6 for the control group. No differences in scores were observed among groups (n.s.). In the control group, a negative correlation was observed between PSQ score and KOOS-pain scores at the end of the follow-up in addition to a positive correlation between PSQ score and rescue analgesia consumption at the first postoperative week. The optimal cutoff value for PSQ score to predict insufficient improvement in KOOS-pain subscale was 5.0 points.
Conclusions
A cutoff value of pain sensitivity questionnaire score above 5.0 points was determined to identify patients with higher sensitivity to pain who underwent arthroscopic partial meniscectomy. These patients reported relatively increased pain and consumed more rescue analgesics postoperatively unless treated with a single intraoperative corticosteroids injection or oral non-steroidal anti-inflammatories. Therefore, surgeons can use pain sensitivity questionnaire score as a preoperative tool to identify patients with high sensitivity to pain and customize their postoperative analgesics protocol to better fit their pain levels.
Level of evidence
II.
In recent years, there has been a surge in the use of natural fiber polymer-based composites in various engineering fields due to their numerous advantages, including lower environmental pollution, ...ease of processing, high strength, and biodegradability. This study employed the Taguchi method to experimentally and statistically examine the effects of various fiber parameters on the tensile strength of a locally developed natural fiber-epoxy composite. The natural fiber used in the study was “Meriz,” a type of goat hair woven into the traditional Kurdish costume known as “Shall.” The fiber parameters examined included fiber orientation angles, weight fraction, form, and color. The results indicated that the tensile strength of the composite was improved by 100% when using the Meriz fiber with certain orientation angles, weight fraction, form, and colors, namely 0°/90°, 10 wt%, Shall, and brown, respectively. The analysis of variance also revealed that the fiber form had the most significant impact on tensile strength, contributing 40.74%. Confirmation testing demonstrated good agreement between the experimental and statistical data. Scanning electron microscopy was utilized to assess the interfacial bonding between the fiber reinforcement and the matrix and to analyze the fracture surface of the specimens with the highest and lowest tensile strength. The results indicated that the specimen with the highest tensile strength had excellent interfacial bonding compared to the specimen with the lowest tensile strength.
•The paper presents the mechanical property through tensile test for epoxy-natural fibre composites.•Taguchi method was utilized to arrange the experiments using mixed model fractional factorial.•Process parameters analysed by ANOVA to show their impact on tensile properties.
Background and Objective: Medical cannabis is becoming an acceptable treatment modality in medicine, especially for pain relief. Concurrently, cannabis use is becoming more prevalent worldwide, a ...public demand-driven trend despite the lack of established scientific basis. This observational open-label study sought to investigate the effectiveness of cannabis therapy for alleviating low back pain symptoms. Methods: Two types of cannabis treatment modalities were sequentially administered to chronic low back pain patients. After an initial 1-month washout period (WO1), the first modality was cannabidiol (CBD)-rich sublingual extract treatment administered for 10 months. Following another washout period, the second modality, Δ⁹-tetrahydrocannabinol (THC)-rich smoked inflorescence (whole dried cannabis flowers) was administered for 12 months. Results: Enrolled in the study were 24 patients whose advanced imaging studies (i.e. computerized tomography or magnetic resonance imaging of the lumbar spine) revealed disc herniation or spinal stenosis. Three patients dropped out of extract therapy treatment but resumed study participation to receive THC-rich smoking therapy. After a minimum of 2 years, cannabis therapy had reduced lower back pain symptoms, as assessed by Oswestry Disability Index, the SF-12 patient-reported outcome questionnaire, and the visual analogue scale. Pain reduction was not significant during the extract treatment part of the study; however, pain reduction was significant during the inhaled therapy part of the study. Conclusions: Our findings indicate that inhaled THC-rich therapy is more effective than CBD-rich sublingual extract therapy for treating low back pain and that cannabis therapy is safe and effective for chronic low back pain.
Purpose
The epidemiology of shoulder instability in the general population is lacking. The aim of the current study was to determine the incidence rate of primary shoulder dislocations requiring ...surgical interventions in a major trauma center within a large maintenance organization.
Methods
A retrospective cohort analysis of electronic health records database from 1 January 2014 and 31 December 2020 was conducted in major rural trauma center. This study included all patients aged 10 years or older with a primary shoulder dislocation that were treated with closed reduction in the emergency room department. An overall incidence density rates (IDR) (per 100,000 person-years) of primary shoulder dislocations and stabilization surgeries were determined for the entire cohort. The data was used to evaluate the age-specific and gender-specific epidemiology.
Results
During the study period of 7 years there were 1,302 patients who underwent closed reduction after a primary shoulder dislocation (mean age 45 years). Of those, a total of 106 shoulder stabilization surgeries (8%) were performed. The IDR of primary shoulder dislocations was 179 per 100,000 person-years. The IDR of primary shoulder stabilizations was 15 per 100,000 person-years. The peak in number of dislocations was observed in the age groups of 20–29 years and over 60 years. In the age groups under 59 years dislocations were more common in men while in ages over 60 years dislocations were more common in women. The vast majority of shoulder stabilization surgeries were performed in young patients (age under 39 years).
Conclusion
The IDR of primary shoulder dislocations calculated from a major trauma center of the largest health maintenance organization in Israel was 179 per 100,000 person-years. Shoulder dislocations had bimodal age distribution. Overall, eight percent of the patients (mainly young) with shoulder dislocations underwent shoulder stabilization surgery during the study period.
Mohair fibres from animals are a great choice for people who care about the environment. They have low toxicity, are abundant in raw materials and don't pose any health risks. However, when compared ...to synthetic fibres, their mechanical performance is not as good. Mohair fibres are best suited for low to medium load applications, such as car parts, agricultural equipment, sports equipment and household items. Despite their excellent properties, there is still a lot we don't know about mohair textile-reinforced polyester composites. The novelty of this study is testing different mohair fibre textiles to see which one provides the best characteristics. The three most commonly used locally-made mohair fabrics (woven, knitted and pressed mat) were selected as reinforcement in polyester resin. Nine different laminates of similar and hybrid layers were made by hand lay-up in a closed mold at a constant fibre weight fraction (number of layers), mold pressure, curing time and temperature. The results showed that the composite laminate of mat fabric reinforced polyester provides the maximum tensile strength, elongation, flexural strength and thermal insulation of 22 MPa, 2.2 %, 54.6 MPa, 0.27 J and 0.012 m2°C/W, respectively. Meanwhile, the woven laminate exhibited the highest impact strength of 0.27 J and the hybrid laminates of the mat and woven fabrics offer satisfactory strength of 0.25 J.
Anterior cruciate ligament (ACL) ruptures are prevalent knee injuries, with approximately 200,000 ruptures annually, and treatment costs exceed USD two billion in the United States alone. Typically, ...the initial detection of ACL tears and anterior tibial laxity (ATL) involves manual assessments like the Lachman test, which examines anterior knee laxity. Partial ACL tears can go unnoticed if they minimally affect knee laxity; however, they will progress to a complete ACL tear requiring surgical treatment. In this study, a computational finite element model (FEM) of the knee joint was generated to investigate the effect of partial ACL tears under the Lachman test (GNRB
testing system) boundary conditions. The ACL was modeled as a hyperelastic composite structure with a refined representation of collagen bundles. Five different tear types (I-V), classified by location and size, were modeled to predict the relationship between tear size, location, and anterior tibial translation (ATT). The results demonstrated different levels of ATT that could not be manually detected. Type I tears demonstrated an almost linear increase in ATT, with the growth in tear size ranging from 3.7 mm to 4.2 mm, from 25% to 85%, respectively. Type II partial tears showed a less linear incline in ATT (3.85, 4.1, and 4.75 mm for 25%, 55%, and 85% partial tears, respectively). Types III, IV, and V maintained a nonlinear trend, with ATTs of 3.85 mm, 4.2 mm, and 4.95 mm for Type III, 3.85 mm, 4.25 mm, and 5.1 mm for Type IV, and 3.6 mm, 4.25 mm, and 5.3 mm for Type V, for 25%, 55%, and 85% partial tears, respectively. Therefore, for small tears (25%), knee stability was most affected when the tears were located around the center of the ligament. For moderate tears (55%), the effect on knee stability was the greatest for tears at the proximal half of the ACL. However, severe tears (85%) demonstrated considerable growth in knee instability from the distal to the proximal ends of the tissue, with a substantial increase in knee instability around the insertion sites. The proposed model can enhance the characterization of partial ACL tears, leading to more accurate preliminary diagnoses. It can aid in developing new techniques for repairing partially torn ACLs, potentially preventing more severe injuries.
Polyp segmentation is an important task in early identification of colon polyps for prevention of colorectal cancer. Numerous methods of machine learning have been utilized in an attempt to solve ...this task with varying levels of success. A successful polyp segmentation method which is both accurate and fast could make a huge impact on colonoscopy exams, aiding in real-time detection, as well as enabling faster and cheaper offline analysis. Thus, recent studies have worked to produce networks that are more accurate and faster than the previous generation of networks (e.g., NanoNet). Here, we propose ResPVT architecture for polyp segmentation. This platform uses transformers as a backbone and far surpasses all previous networks not only in accuracy but also with a much higher frame rate which may drastically reduce costs in both real time and offline analysis and enable the widespread application of this technology.
Abstract
A field experiment was conducted in the fields of the College of Agriculture - University of Tikrit during the autumn season for the year (2022) to find out the effect of nitrogen fertilizer ...fractionation on the growth of corn in gypsum soil.Where the experiment included three factors, the first factor, five dates for nitrogen fertilizer fractionation, symbolized by the letter T (T1, the first appointment / half of the quantity at planting and the other half after (30) days of planting, and T2, the second appointment / one-third of the quantity at planting and two-thirds after (30) days of cultivation and T3 third date / one-third of the quantity at planting and one-third after (30) days of cultivation and a third after the passage of (60) days of cultivation and T4 the fourth date / one-fifth of the quantity when planting, fifty-five after the passage of (30) days of cultivation and fifty after the passage of (60) days of cultivation and T5 the fifth date / two-fifths at planting and fifty after a month of cultivation and one-fifth of the quantity After the passage of (60) of cultivation. The second factor is two levels of nitrogen fertilizer, denoted by the symbol N, namely (N1) (320) kg N ha
-1
and (2N) (360) kg N ha
-1
. The third factor is Adding method, denoted by the symbol M, the BroadcastingM1 method) and the Bands(M2) method. All the results showed that the retail treatment of the fourth appointment, T4, excelled in all traits, and the second level, N2 (360) kg N ha
-1
, gave the highest significant difference in all traits, and the addition of the second method, M2 (Bands method), also gave excelled in all studied traits.The results showed that the treatment T4N2M2 gave the highest values in the studied traits (the number of rows per ear, the number of grains per ear, the weight of 500 grains, and the total grain yield), as it reached (18.01) row cob
-1
, (739) grain cob
-1
, (163.01) gm, and (14.08)) ton ha
-1
, respectively.
The aim of this study was to evaluate which specific factors influence the improvement in function and to estimate the time to obtain pain relief following arthroscopic rotator cuff repair.
A total ...of 97 patients (57 men and 40 women; mean age: 55.5 ± 9.3 years) who had arthroscopic rotator cuff repair between 2013 and 2016 were included into the study. Multivariable stepwise analysis included preoperative variables (age, gender, body mass index, comorbidities, occupation and participation in sports, Oxford shoulder score at baseline, preceding injury and duration of preoperative symptoms) and arthroscopic findings (size of rotator cuff tear, pathology of the long head of the biceps and cartilage lesions). The change in the Oxford shoulder score at the last follow-up was modeled as a function of the above predictor variables. The time to regain a visual analogue scale (VAS) under two points following surgery was considered the time to regain substantial pain relief.
The mean follow-up time was 33.2 ± 14.4 months. Twenty three patients had partial thickness and seventy four had full thickness supraspinatus tears. In third of the patients the tears were defined as large full thickness. At the last follow-up the mean Oxford shoulder score improved from 13.8 ± 4.8 to 42.1 ± 7.2 points (P < 0.001). The mean VAS improved from a preoperative score of 6.7 ± 1.3 points to 1.5 ± 0.6 points postoperatively (P < 0.001) and 80 (83%) patients declared they were satisfied to have had the operation. The mean time interval for substantial pain relief was 4.9 ± 3.6 months. Patients with higher preoperative Oxford shoulder score and larger tear size were correlated with lesser improvement in Oxford shoulder score (R = 0.5, P = 0.001).
Arthroscopic rotator cuff repair improved pain and function at an average follow-up of three years. A substantial pain relief was regained within five months from surgery. Larger rotator cuff tear size and more favorable preoperative function were predictors of worse postoperative function.
Level IV, Therapeutic study.
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