Stabilization and solidification of arsenic contaminated silty sand using alkaline activated slag.

Contamination of soils by arsenic represents a significant environmental and public health risk, making effective remediation strategies a pressing concern. One commonly employed technique is stabilization and solidification, which involves the addition of stabilizing binders such as cement to immobilize arsenic. This study investigates the potential of alkaline activated slag for stabilization and solidification of arsenic-contaminated soil, employing the toxic characteristic leaching procedure (TCLP) and unconfined compressive strength (UCS) tests. To assess the strength and leachability behavior, the research examines the effect of several factors, including binder content, curing time, curing conditions, alkaline activator solution to slag ratio, sodium silicate to sodium hydroxide ratio, and sodium hydroxide concentration. Additionally, field emission scanning electron microscopes (FE-SEM) in combination with energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) tests are employed to analyze the stabilization and solidification mechanism. The study shows that increasing the slag content to 20% by weight after 28 days of curing at ambient temperature leads to a decrease of almost 92% in the concentration of leached arsenic and an increase in UCS from 80 kPa to approximately 19 MPa. The formation of albite and anorthite crystals, along with gels such as (N, C)-A-S-H and C-S-H, contributes to enhanced strength and reduced leachability. As a result, the use of alkaline activated slag is identified as an effective and environmentally friendly approach for the stabilization/solidification of arsenic-contaminated soils. This study highlights the use of alkaline activated slag as an effective solution for remediating arsenic-contaminated soils while simultaneously reducing waste, greenhouse gas emissions, and energy consumption. Slag, a byproduct of metal production, is often wasted due to a lack of value and landfill space. However, alkaline activated slag demonstrates the potential to stabilize soil, immobilize heavy metals, and provide efficient and sustainable soil remediation.

Return to Sports Following Meniscal Allograft Transplantation Is Possible but Remains Questionable: A Systematic Review.

OBJECTIVE: To evaluate the return to sports rate and time following meniscal allograft transplantation (MAT). METHODS: PubMed, Web of Science, and Embase were searched in December 2020. Eligibility criteria included clinical studies reporting the return to sport rate following MAT with ≥12-month follow-up. RESULTS: A total of 14 case series were included with 670 patients. The bone bridge technique was used for all transplantations in 5 studies, and suture fixations with bone tunnels were used for all transplantations in 5 studies. In 2 studies, bone plugs were used for medial menisci and bone bridge for lateral menisci. In 1 study, suture fixation was used for medial menisci, and bone bridge for lateral menisci. The return to sports rate ranged from 20% to 91.7%, with 2 studies reporting low return to sport rates. The return to sport time ranged between 7.6 and 16.9 months. The return to preinjury level had a rate of 7% to 100%. Return to a higher level of sports was reported in only 2 studies (28.5% to 86%). Return to a lower level of sports was reported in low proportions in most studies. In terms of patient-reported outcomes, the Lysholm knee and subjective International Knee Documentation Committee (IKDC) scores and Knee Osteoarthritis Outcome Score (KOOS) had significant improvements after MAT. The KOOS quality of life subscore did not change significantly in 1 study. The total reoperation rate after MAT ranged between 3.1% and 80%, whereas the total failure ranged between 1.1% and 30.1%. CONCLUSION: Despite that most studies reporting high return to sports rates, the current level of evidence is low, with all studies being case series. There is significant variability in the reported return to sports rate, time, and level. Therefore, high-quality comparative studies are mandated to elucidate whether MAT is associated with higher return to sports rates and levels. LEVEL OF EVIDENCE: IV, systematic review.

A comparison between constitutive models for the municipal solid waste.

This paper compares the behavioural models of municipal solid waste (MSW) using the corresponding experimental data. To do so, the proposed models are first reviewed and, then, the algorithms and codes of different models are written. After obtaining each model's algorithm, the same experimental data are considered as input, and the strain-stress curve is plotted for each model. In the first method, the total strain in the waste is obtained based on the summation of the elastic, plastic, biological, and creep strains. Afterward, the equivalent stress is obtained. In this method, using biological changes over time, the age of the waste is calculated as an effective parameter in MSW behaviour. Moreover, the effect of creep on the waste is considered independently. In the second algorithm, MSW is considered as fibre and paste material, and the strain-stress curve is obtained. In this method, the waste is considered as a soil model, and the effect of different parameters are calculated. Due to the complexity of the MSW behaviour and considering various parameters, such as the age of the waste, E changes over time, creep, and biological changes, the Krase model has less error than the other models. Using the soil behaviour model for the waste has a significant error, indicating the difference between the results for the behaviours of the two substances.

Surgical anatomy of the axillary artery: clinical implications for open shoulder surgery.

BACKGROUND: Axillary artery injury is a devastating complication related to anterior shoulder surgery and can result in significant morbidity and/or mortality. The purpose of our study was to evaluate the course of the axillary artery in relation to bony landmarks of the shoulder and identify variations in artery position with humeral external rotation. MATERIALS AND METHODS: Dissection of 18 shoulders (9 fresh whole-body cadavers) with simulated vessel perfusion using radiopaque dye was performed. The axillary artery position was measured from multiple points including 2 points on the coracoid base (C1 and C2), 3 points on the coracoid tip (C3-C5), 4 points on the glenoid: superior, middle, and inferior glenoid (D1-D4), and 2 points on the lesser tuberosity (L1 and L2). Fluoroscopic measurements were taken and compared at 0° and 90° of external rotation (F1 vs. F1' and F2 vs. F2'). Manual and fluoroscopic measurements were compared with one another using Kendall's τb correlation. RESULTS: There were 6 male and 3 female cadavers with an average age of 67.2 ± 9.3 years (range: 49-77 years). The mean distance from the axillary artery to the coracoid base (C1 and C2) measured 21.1 ± 7.3 and 22.3 ± 7.4 mm, respectively, whereas the mean distance to the coracoid tip (C3, C4, and C5) measured 30.7 ± 9.3, 52.1 ± 20.2, and 46.5 ± 14.3 mm, respectively. Measurements relative to the glenoid face (D1, D2, and D3) showed a progressive decrease in mean distance from superior to inferior, measuring 31.6 ± 10.3, 16.5 ± 7.5, and 10.3 ± 7.3 mm, respectively, whereas D4 (inferior glenoid to axillary artery) measured 17.8 ± 10.7 mm. The minimum distance from the axillary artery to any point on the glenoid was as close as 4.1 mm (D3). There was a statistically significant difference in F1 (0° external rotation) vs. F1' (90° external rotation) (18.5 vs. 13.4 mm, P = .03). Kendall's τb correlation showed a strong, positive correlation between manual and fluoroscopic measurements (D4: 16.0 ± 12.5 mm vs. F1: 18.5 ± 10.7 mm) (τb = 0.556, P = .037). CONCLUSION: The axillary artery travels an average of 1-1.8 cm from the inferior glenoid margin, which puts the artery at significant risk. In addition, the artery is significantly closer to the inferior glenoid with humeral external rotation. Surgeons performing anterior shoulder surgery should have a thorough understanding of the axillary artery course and understand changes in the position of the artery with external rotation of the humerus.

Prosthetic Bearing Surfaces in Anatomic and Reverse Total Shoulder Arthroplasty.

Total shoulder arthroplasty (TSA) and reverse TSA have provided an effective treatment for glenohumeral osteoarthritis; however, longevity of the procedure may be limited by osteolysis and polyethylene wear. In TSA, glenoid component failure occurs through several mechanisms, the most common being aseptic loosening and polyethylene wear. Newer bearing surfaces such as highly cross-linked ultra-high-molecular-weight polyethylene, vitamin E processing, ceramic heads, and pyrolytic carbon surfaces have shown improved wear characteristics in biomechanical and some early clinical studies. The purpose of this review is to provide a historical perspective and current state of the art of bearing surface technology in anatomic and reverse TSA.

There is an App for That: Mobile Technology Improves Complication Reporting and Resident Perception of Their Role in Patient Safety.

Morbidity and mortality (M&M) conferences are rooted within the culture of medicine. They serve a role in every training program and have been mandated by the Accreditation Council for Graduate Medical Education in surgical programs since 1983. Despite the patient safety improvements and educational benefits of these conferences, many adverse events are grossly under-reported. METHODS: We developed a web-based, Health Insurance Portability and Accountability Act-compliant, M&M reporting mobile application based on Research Electronic Data Capture. The list of possible complications was based on the American Board of Orthopaedic Surgery complications list for part II. The interface is accessible through all mobile platforms. All residents were encouraged to use the application for real-time reporting of complications. Using an unpaired T-test, we compared the reporting before and after the implementation of the mobile application. Residents were surveyed using the Agency for Healthcare Research and Quality Patient Safety Culture Survey before and after implementation to evaluate resident perception of the department's culture of safety. RESULTS: The application was launched in August 2017. All reported events were tallied from August 2016 through July 2019. Before the implementation of the application, there were 54 adverse events reported, with a mean of 4.0 per month. In the Post-App cohort, a total of 176 adverse events were reported in year 1, with a mean of 14.76 per month, and 236 adverse events were reported in year 2, with a mean of 19.66 per month. Residents were significantly more likely to feel that their input on patient safety was valued by attendings after the implementation of the app (p = 0.0243). CONCLUSIONS: An anonymous mobile reporting method for M&M significantly increased the reporting of both major and minor complications and improved resident perception of their role in patient safety efforts. This suggests that traditional methods of M&M reporting may grossly underestimate the complication rates which can negatively affect patient safety and quality improvement efforts and that reducing barriers to the reporting of complication may improve resident engagement in patient safety.

Hip Adductor Longus Tendon Origin Anatomy Is Consistent and May Inform Surgical Reattachment.

PURPOSE: To define the topographic anatomy of the footprint of the adductor longus origin on the pubis and its underlying bony morphology to better inform surgical repair of adductor longus tendon injuries. METHODS: Five cadaveric pelvis specimens were dissected, making 10 adductor footprints available for analysis. The adductor longus tendon origin was isolated and the surrounding tissue debrided. The circumference of the tendinous attachment to the pubic crest was marked before excising the tendon and fibrocartilage enthesis from the pubis. Radiopaque paint was prepared by mixing 30 mL of all-purpose acrylic paint (Anita's no. 11150 Island Blue; Rust-Oleum Corp, Vernon Hills, IL) with 15g of E-Z-HD 98% w/w barium sulfate (Bracco Diagnostics Inc., Anjou Quebec, Canada) and applied to the marked footprint. The specimens underwent a 1.0-mm slice computed tomographic scan with 3-dimensional reconstructions. Synapse PACS (FujiFilm, Valhalla, NY) software for measurements of the tendon footprint and underlying bone. RESULTS: Average age and weight of the specimens at the time of death was 37 years and 204.6 ± 48.7 lbs, respectively. The width and length of the tendon origin was 12.0 ± 1.1 mm and 10.9 ± 1.1 mm, respectively. The distance of the center of the footprint from the center of the pubic tubercle was 8.5 ± 1.4 mm lateral and 12.2 ± 0.4 mm caudal. The osseous thickness underlying the footprint was 18.7 ± 3.7 mm at an angle of 34.5 ± 1.5° in relation to the sagittal plane. The correlation between specimen body weight and the thickness of the bone underlying the footprint was strongly positive (r = 0.92). CONCLUSIONS: We found that there is a consistent angle from the center of the adductor longus tendon footprint to the point of maximal underlying bony thickness, as well as a positive correlation between body mass index and osseous thickness, which may inform anatomic reattachment of this tendon. CLINICAL RELEVANCE: Our findings will assist surgeons in identifying the footprint of the adductor longus tendon and safely perform anatomic repair of adductor longus tendon avulsions.

Arthroscopic Repair of a Coronoid Process Fracture: A Case Report.

CASE: A 68-year-old woman sustained an isolated type III left coronoid fracture after mechanical ground-level fall. The patient underwent left elbow arthroscopy with minimally invasive arthroscopic reduction and internal fixation of the coronoid fracture using Arthrex Mini TightRope. The patient achieved successful elbow stabilization with a postoperative Mayo Elbow Score of 100. CONCLUSION: We present a case report of a novel technique in coronoid fracture management with stable fixation, minimal soft-tissue violation, and restoration of highly functional elbow range of motion. Minimal soft-tissue violation with use of arthroscopy and suture button was the key element in successful surgical treatment and outcome.

Standing electric scooter injuries: Impact on a community.

BACKGROUND: This study investigates the impact of standing electric scooter-related injuries within an entire integrated hospital system. METHODS: We performed a retrospective review of patients involved in standing electric scooter incidents presenting throughout an urban hospital network over a 10 month period. Rates of Google searches of scooter-related terms performed locally were used as a surrogate for ride frequency. Injury, mechanism, and cost data were analyzed. RESULTS: Data on 248 patients were reviewed. Twenty-three (9%) were under 18 years old. Loss of balance was the most common cause of injury accounting for nearly half, while tripping over a scooter 14 (6%) affected the elderly disproportionately. Eight (3%) riders wore helmets. All TBI and closed head injuries occurred in unhelmeted patients. Most incidents occurred in the street, only one in a bicycle lane. Facilities costs were greater for patients under the influence of alcohol and marijuana. CONCLUSION: Policies related to the use of mandated safety equipment, dedicated bicycle lanes, and the proper storage of empty vehicles should be further investigated.

Fascia Iliaca Regional Anesthesia in Hip Fracture Patients Revisited: Which Fractures and Surgical Procedures Benefit Most?

OBJECTIVES: Perioperative fascia iliaca regional anesthesia (FIRA) decreases pain in hip fracture patients. The purpose of this study is to determine which hip fracture types and surgical procedures benefit most. DESIGN: Prospective observational study compared with a retrospective historical control. PATIENTS/PARTICIPANTS: Patients older than 60 years who received perioperative FIRA were compared with a historical cohort not receiving FIRA. SETTING: This study was conducted at a Level 1 trauma center. MAIN OUTCOME MEASUREMENTS: The primary outcome was morphine milliequivalents (MME) consumed during the index hospitalization. Fracture pattern-specific preoperative and postoperative MME consumption and surgical procedure-specific postoperative MME consumption was compared between the FIRA and non-FIRA groups. RESULTS: A total of 949 patients were included in this study, with 194 (20.4%) patients in the prospective protocol group. There were no baseline differences between cohorts. Preoperatively, only femoral neck fracture patients receiving FIRA used fewer MME (P < 0.001). Postoperatively, femoral neck fracture patients receiving FIRA used fewer MME on postoperative day (POD) 1 (P = 0.027) and intertrochanteric fracture patients used fewer MME on POD1 and POD2 (P = 0.013; P = 0.002). Cephalomedullary nail patients receiving FIRA used fewer MME on POD1 and POD2 (P = 0.004; P = 0.003). Hip arthroplasty patients receiving FIRA used fewer MME on POD1 (P = 0.037). Percutaneous pinning and sliding hip screw patients had no significant MME reduction from FIRA. CONCLUSIONS: Preoperatively, patients with femoral neck fractures benefit most from FIRA. Postoperatively, both patients with femoral neck fractures and intertrochanteric fractures benefit from FIRA. Patients undergoing cephalomedullary nail fixation or hip arthroplasty benefit most from FIRA postoperatively. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

A Comparison in Outcomes of Preoperative Single-shot versus Continuous Catheter Fascia Iliaca Regional Anesthesia in Geriatric Hip Fracture Patients.

BACKGROUND: Fascia iliaca nerve blocks relieve pain in geriatric hip fracture patients and can be administered via a single-shot or continuous catheter. We compared perioperative opioid consumption and pain scores between these two blocks. METHODS: We performed a prospective, observational cohort study, including geriatric hip fracture patients who received a preoperative block. We compared morphine milligram equivalent (MME) consumption and visual analog scale (VAS) pain scores between single-shot and continuous fascia iliaca blocks at multiple time points: preoperative and on postoperative (POD) day 0, 1, and 2. We compared the change in preoperative total and hourly opioid consumption before and after block placement within and between groups. Secondary outcomes included opioid related adverse events, length of stay, and readmission rates. RESULTS: 107 patients were analyzed, 66 received a single-shot and 41 a continuous block. No significant differences were found between both blocks at any time point for median MME consumption or pain scores. MME [IQR]: preoperative 20.5 [6.0,48.8] vs. 24.0 [8.8,48.0], p=0.95; POD0 6.0 [0.0,18.6] vs. 10.0 [0.0,14.0], p=0.52; POD1 12.0 [0.0,30.0] vs. 18.0 [5.0,24.0], p=0.69; POD2 6.0 [0.0,21.2] vs. 12.0 [0.0,24.0], p=0.54. VAS [IQR]: preoperative 4.0 [2.2,5.3] vs. 4.6 [3.2,5.3], p=0.34; POD0 1.3 [0.0,3.7] vs. 2.5 [0.0,3.6], p=0.73; POD1 2.9 [1.7,4.4] vs. 3.7 [1.5,4.7], p=0.59; POD2 2.4 [1.0,4.4] vs. 3.3 [1.9,4.2], p=0.18. Preoperative MME/hr significantly decreased after the block for both groups: 1.05 [0.0,2.2] to 0.0 [0.0,0.0], p < 0.001; 1.4 [0.6,3.1] to 0.0 [0.0,0.1], p < 0.001. The reduction in MME/hr between groups was not significantly different: 0.9 [0.0,1.9] vs. 1.4 [0.6,3.1], p = 0.067. We found no significant differences in secondary outcomes between groups. CONCLUSIONS: We report no differences in opioid use and pain scores between single-shot and continuous catheter fascia iliaca nerve blocks. Both blocks similarly reduce preoperative opioid consumption.

Time to Block: Early Regional Anesthesia Improves Pain Control in Geriatric Hip Fractures.

BACKGROUND: Fascia iliaca nerve blocks (FIBs) anesthetize the thigh and provide opioid-sparing analgesia for geriatric patients with hip fracture awaiting a surgical procedure. FIBs are recommended for preoperative pain management; yet, block administration is often delayed for hours after admission, and delays in pain management lead to worse outcomes. Our objective was to determine whether opioid consumption and pain following a hip fracture are affected by the time to block (TTB). We also examined length of stay and opioid-related adverse events. METHODS: This prospective cohort study included patients who were ≥60 years of age, presented with a hip fracture, and received a preoperative FIB from March 2017 to December 2017. Individualized care timelines, including the date and time of admission, block placement, and surgical procedure, were created to evaluate the effect that TTB and time to surgery (TTS) had on outcomes. Patterns among TTB, TTS, and morphine milligram equivalents (MME) were investigated using the Spearman rho correlation. For descriptive purposes, we divided patients into 2 groups based on the median TTB. Multivariable regression for preoperative MME and length of stay was performed to assess the effect of TTB. RESULTS: There were 107 patients, with a mean age of 83.3 years, who received a preoperative FIB. The median TTB was 8.5 hours. Seventy-two percent of preoperative MME consumption occurred before block placement (pre-block MME). A longer TTB was most strongly correlated with pre-block MME (rho = 0.54; p < 0.001), and TTS was not correlated. Patients with a faster TTB consumed fewer opioids preoperatively (12.0 compared with 33.1 MME; p = 0.015), had lower visual analog scale scores for pain on postoperative day 1 (2.8 compared with 3.5 points; p = 0.046), and were discharged earlier (4.0 compared with 5.5 days; p = 0.039). There were no differences in preoperative pain scores, postoperative opioid consumption, delirium, or opioid-related adverse events. Multivariate regression showed that every hour of delay in TTB was associated with a 2.8% increase in preoperative MME and a 1.0% increase in the length of stay. CONCLUSIONS: Faster TTB in geriatric patients with hip fracture may reduce opioid use, pain, and length of stay. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

A laboratory study on the MSW mechanical behavior in triaxial apparatus.

Shear strength characterization of MSW materials is a mandatory task when performing analyses related to landfill design and landfill geometry improvements. Despite the considerable amount of research focusing on MSW mechanical behavior there remain certain aspects which are not completely understood and deserve attention in particular the case of the undrained behavior of MSW. This paper presents the results of a comprehensive laboratory testing program using a large-scale triaxial apparatus at the Federal University of Bahia, Salvador, Brazil. The effect of factors such as confining pressure, unit weight, fiber content, rate of loading and over-consolidation on the MSW mechanical response were investigated. Tested samples presented typical MSW shear/strain curves (concave upward) in all the tests, despite the pore water pressure reaching levels almost equal to the confining pressure. The obtained results show that increasing confining stress, unit weight, loading rate, fiber content and over-consolidation lead to an increase in the MSW shear strength. The importance of the fibrous components in the waste behavior is highlighted and graphs showing the variation of the MSW shear strength with fiber content in different drainage conditions are shown. The authors believe these results could be of interest to many companies, especially considering the new trend of plastic material recycling (prior landfilling) for energy recovery purposes.

Municipal solid waste effective stress analysis.

The mechanical behavior of municipal solid waste (MSW) has attracted the attention of many researchers in the field of geo-environmental engineering in recent years and several aspects of waste mechanical response under loading have been elucidated. However, the mechanical response of MSW materials under undrained conditions has not been described in detail to date. The knowledge of this aspect of the MSW mechanical response is very important in cases involving MSW with high water contents, seismic ground motion and in regions where landfills are built with poor operation conditions. This paper presents the results obtained from 26 large triaxial tests performed both in drained and undrained conditions. The results were analyzed taking into account the waste particles compressibility and the deformation anisotropy of the waste samples. The waste particles compressibility was used to modify the Terzaghi effective stress equation, using the Skempton (1961) proposition. It is shown that the use of the modified effective stress equation led to much more compatible shear strength values when comparing Consolidated-Drained (CD) and Consolidated-Undrained (CU), results, explaining the high shear strength values obtained in CU triaxial tests, even when the pore pressure is almost equal to the confining stress.