Selective Upcycling of Polyolefins into High-Value Nitrogenated Chemicals.

The selective upcycling of polyolefins to create products of increased value has emerged as an innovative approach to carbon resource stewardship, drawing significant scientific and industrial interest. Although recent advancements in recycling technology have facilitated the direct conversion of polyolefins to hydrocarbons or oxygenated compounds, the synthesis of nitrogenated compounds from such waste polyolefins has not yet been disclosed. Herein, we demonstrate a novel approach for the upcycling of waste polyolefins by efficiently transforming a range of postconsumer plastic products into nitriles and amides. This process leverages the catalytic properties of manganese dioxide in combination with an inexpensive nitrogen source, urea, to make it both practical and economically viable. Our approach not only opens new avenues for the creation of nitrogenated chemicals from polyolefin waste but also underscores the critical importance of recycling and valorizing carbon resources originally derived from fossil fuels. This study provides a new upcycling strategy for the sustainable conversion of waste polyolefins.

The learning curve for minimally invasive Achilles repair using the "lumbar puncture needle and oval forceps" technique.

INTRODUCTION: An acute Achilles tendon rupture represents a common tendon injury, and its operative methods have been developed over the years. This study aimed to quantify the learning curve for the minimally invasive acute Achilles tendon rupture repair. METHODS: From May 2020 to June 2022, sixty-seven patient cases who received minimally invasive tendon repair were reviewed. Baseline data and operative details were collected. The cumulative summation (CUSUM) control chart was used for the learning curve analyses. Achilles tendon rupture score (ATRS), American Orthopedic Foot and Ankle Society (AOFAS) ankle/hindfoot score, and visual analog scale (VAS) at 3/6/9/12 months were calculated to assess the clinical outcomes. RESULTS: Thirty-six cases underwent at least a year of follow up and were enrolled in this study. The gender ratio and average age were 80.5% and 32.5 years. The linear equation fitted well (R2 = 0.95), and CUSUM for operative time peaked in the 12th case, which was divided into the learning phase (n = 12) and master phase (n = 24). No significant difference was detected between the two groups in clinical variables, except for the operative time (71.1 ± 13.2 min vs 45.8 ± 7.2 min, p = 0.004). Moreover, we detected one case with a suture reaction and treated it properly. CONCLUSION: Minimally invasive Achilles repair provides an opportunity for early rehabilitation. Notably, the learning curve showed that the "lumbar puncture needle and oval forceps" technique was accessible to surgeons.

Comparison between screw fixation and plate fixation via sinus tarsi approach for displaced intra-articular calcaneal fractures: a systematic review and meta-analysis.

BACKGROUND: Optimal surgical fixation for displaced intra-articular calcaneal fractures (DIACF) remains a subject of debate, particularly regarding the superiority between screw fixation and plate fixation via the sinus tarsi approach (STA). This review aims to determine the preferred treatment for DIACF and compare the outcomes of minimally invasive surgery options. METHODS: Our study involved thorough searches across multiple electronic databases, including PubMed, Cochrane, Embase, and Web of Science, to identify all relevant publications on distal intra-articular fractures of the calcaneus (DIACFs) that were fixed using cannulated screws or plates via STA. Through a comprehensive meta-analysis, we evaluated several outcomes, including post-operative function, radiological measurements, and complications. RESULT: A total of 728 patients from 7 studies met the inclusion criteria. Among them, 435 patients underwent screw fixation via STA, and 373 patients underwent plate fixation via STA. The study found no statistically significant differences between the screw fixation and the plate fixation via sinus tarsi approach (STA) in terms of AOFAS scores, Bohler's angle, Gissane's angle, sural nerve injury, secondary subtalar arthrodesis and reoperation. Compared with screw fixation, plate fixation via STA can reduce reduction loss of Bohler's angle (WMD = - 1.64, 95% CI = [- 2.96, - 0.31], P = 0.06, I2 = 59%), lower the incidence of fixation failure (OR = 0.32, 95% CI = [0.13, 0.81], P = 0.78, I2 = 0%), and decrease intra-articular step-off (WMD = - 0.52, 95% CI = [- 0.87, - 0.17], P = 0.66, I2 = 0%). CONCLUSIONS: Plate fixation demonstrates superior capability in restoring calcaneal width, maintaining Bohler's angle, and minimizing intra-articular step-off, thereby maintaining better reduction of the subtalar articular surface. In addition, plate fixation exhibits the modest complication rate and a low incidence of fixation failure. Therefore, we recommend the use of plate fixation through the STA, especially for complex and comminuted intra-articular calcaneal fractures.

Comparison between anterior-to-posterior screw fixation versus posterolateral approach plate fixation for posterior malleous fracture: A systematic review and meta-analysis.

PURPOSE: There are two main surgical fixation methods for the posterior malleolar fractures (PMFs), the anterior-to-posterior (AP) screws or via the posterolateral (PL) approach utilizing a buttress plate. This review aims to compare the clinical outcome between the AP screw fixation and the PL plate fixation for treating PMFs. METHODS: We searched all relevant publications about PMFs treated with AP screws or PL plates through electronic databases including the PubMed, the Cochrane Library, the Embase, the Wiley online library and the Web of Science. The meta-analysis was conducted to evaluated clinical outcomes including reduction quality, post-operative function and complications. RESULTS: Six studies (one single randomized controlled trial and five retrospective cohort studies) were enrolled. 172 patients underwent AP screw fixation and 214 patients underwent PL plate fixation with a total of 386 patients (169 males and 217 females). The PL plating group yielded better AOFAS scores(MD = 6.97, 95 % CI=[4.68, 9.27], P＜0.00001, I2 =0 %) and was more likely to achieve excellent anatomical reduction(OR=5.49, 95 % CI=[1.06, 28.42], P = 0.04, I2 =80 %). No differences were found in the bad reduction quality, incidences of complications (arthritis, neuralgia, superficial wound healing problems and implant failure), the walking VAS scores and the dorsiflexion restriction degrees. CONCLUSION: We suggest that the PL plate fixation method has the clinical benefit of achieving anatomical reduction and better AOFAS scores over the AP screw fixation for treating PMFs. No differences were found in the incidences of complications ( arthritis, neuralgia, superficial wound healing problems and implant failure), the walking VAS scores and the dorsiflexion restriction degrees. The posterior approach and the direct reduction are recommended for the treatment of the PMFs. LEVEL OF CONFIDENCE: Ⅱb.

Comparison of operatively and nonoperatively treated isolated mason type II radial head fractures: a systematic review and meta-analysis.

BACKGROUND: Radial head fractures are the most common bony injury of the elbow in adults. The current literature does not agree on whether isolated stable type II radial head fractures should be treated operatively or nonoperatively. This review aims to determine the preferred treatment for Mason type II radial head fractures and compare the outcomes of conservative and surgical treatment. METHODS: Our study used PRISMA guidelines and conducted a thorough search of multiple electronic databases, including PubMed, Cochrane, Embase, Web of Science, CNKI, and Wanfang databases, initially identifying 545 relevant publications on surgical and conservative treatment of Mason type II radial head fractures. The final search date for this study is July 7, 2024.Through a comprehensive meta-analysis, we evaluated several outcomes, including functional scores (DASH, OES, and MEPS scores), clinical outcomes (elbow flexion, elbow extension deficit, elbow pronation, and elbow supination), and complication rate (total complications and elbow pain). The mean difference (MD) was compared for continuous outcomes, and the odds ratios (ORs) were compared for categorical outcomes. RESULT: A total of 271 patients from 4 studies met the inclusion criteria. Among them, 142 patients received surgical treatment and 129 patients received non-surgical treatment. The study found no statistically significant differences between surgical and non-surgical treatments in DASH, OES, MEPS, elbow flexion, elbow extension impairment, and elbow pain. Compared with surgical treatment, non-surgical treatment was associated with greater elbow pronation (OR = -3.10, 95% CI = [-4.96, -1.25], P = 0.55, I2 = 0%) and a lower complication rate (OR = 5.54, 95% CI = [1.79, 17.14], P = 0.42, I2 = 0%). CONCLUSION: Based on the current evidence, conservative management of isolated Mason II radial head fractures yields favorable therapeutic outcomes with a low incidence of complications.

Catalytic conversion of mixed polyolefins under mild atmospheric pressure.

The chemical recycling of polyolefin presents a considerable challenge, especially as upcycling methods struggle with the reality that plastic wastes typically consist of mixtures of polyethylene (PE), polystyrene (PS), and polypropylene (PP). We report a catalytic aerobic oxidative approach for polyolefins upcycling with the corresponding carboxylic acids as the product. This method encompasses three key innovations. First, it operates under atmospheric pressure and mild conditions, using O2 or air as the oxidant. Second, it is compatible with high-density polyethylene, low-density polyethylene, PS, PP, and their blends. Third, it uses an economical and recoverable metal catalyst. It has been demonstrated that this approach can efficiently degrade mixed wastes of plastic bags, bottles, masks, and foam boxes.

Comparison of arthroscopic and open Brostrom-Gould surgery for chronic ankle instability: a systematic review and meta-analysis.

BACKGROUND: Approximately 20% of acute ankle sprains progress to chronic lateral ankle instability (CLAI) requiring surgical intervention. There has been growing interest among surgeons regarding whether arthroscopic techniques can replace open Brostrom-Gould surgery in treating CLAI. The purpose of this study was to pool the results of multiple studies comparing the treatment effects of these two fixation approaches. METHODS: Our study involved thorough searches across multiple electronic databases, including PubMed, Cochrane, Embase, and Web of Science, to identify all relevant publications on CLAI that were repaired using the arthroscopic or open Broström-Gould technique. Through a comprehensive meta-analysis, we evaluated several outcomes, including post-operative function, radiological measurements, complications, and time efficiency. RESULT: A total of 686 patients from 11 studies were included in the analysis. Among them, 351 patients underwent open repair, and 335 underwent arthroscopic Brostrom-Gould surgery. The present study revealed that arthroscopic and open Brostrom-Gould techniques demonstrated no significant differences in talar tilt, talar anterior translation, complication rate, and time to return to previous level of activity. Furthermore, no significant differences were observed in AOFAS, K-P, VAS, and Tegner scores at the 2-year follow-up. However, significant differences were noted between the two surgical approaches in terms of early weight-bearing (WMD = - 1.33 weeks, 95% CI = [- 1.91, - 0.76], P = 0.17, I2 = 40%), as well as AOFAS scores (WMD = 1.00, 95% CI = [0.05, 1.95], P = 0.73, I2 = 0%), K-P scores (WMD = 1.57, 95% CI = [0.49, 2.64], P = 0.15, I2 = 47%), and VAS scores (WMD = - 0.15, 95% CI = [- 0.60, 0.29], P < 0.08, I2 = 61%) within the first postoperative year. CONCLUSIONS: Our findings support that arthroscopic repair yields comparable outcomes to open surgery. Consequently, we advocate for adopting arthroscopic repair as a preferred alternative to the conventional open Broström-Gould procedure for treating chronic lateral ankle instability.

Elbow dislocation approach for complex elbow fractures: a cadaveric study.

BACKGROUND: Approach need to be considered when surgeons dealt with complex elbow injuries and the choice of the approach is a challenge for surgeons due to the complex anatomy. On the basis of releasing the lateral collateral ligament, we modified the dislocation technique to pursue the superior exposure including not only the distal humeral surface but also the anterior facet of the coronoid process. METHODS: A total of 4 cadaver specimens and 8 elbows were included in the study. Each cadaver provided one elbow for either the elbow dislocation approach or the posterior olecranon approach. The exposed distal articular surface of humerus, humeral capitulum, humeral trochlea, anterior trochlea of distal humerus, posterior trochlea of distal humerus and the ulnar coronoid process surface were marked by image J software and calculated for a comparison for each surgical approach. RESULTS: The total distal humeral surface was exposed as a median of 98.2 (97.6, 99.6)% and 62.0 (58.3, 64.5)% for the elbow dislocation approach and the olecranon osteotomy approach (P < 0.001), the capitulum 100% and 32.4 (28.0, 39.2)% (P < 0.001), the trochlea 93.2(90.1, 96.9)% and 72.5 (65.2, 78.8)% (P < 0.001), the anterior trochlear articular surface 96.0(93.0, 97.4)% and 50.3 (43.6, 59.1)% (P < 0.001), the posterior trochlear articular surface 95.4 (93, 100)% and 100% (P = 0.76) and the articular surface of the coronoid process of ulna 71.3 (66.0, 74.2)% and 0% (P < 0.001). CONCLUSION: For complex elbow fractures, the technique of elbow dislocation provides complete exposure of the distal humerus surface and a significant portion of the coronoid process surface, facilitating direct visualization for reduction and fixation. Level of evidence Anatomy Study; Cadaver Dissection.

Synergistic Ni/Cu catalyzed migratory arylsilylation of terminal olefins.

Synthesis of organosilanes from alkenes is a very important topic owing to their wide applications. A Ni/Cu dual metal-catalyzed arylsilylation of terminal alkenes, featuring migratory selectivity, has been developed. A wide diversity of aliphatic silanes have been prepared from terminal alkenes, aryl halides and Suginome's reagent. This protocol is highlighted by excellent regioselectivity, mild reaction conditions and good functional group tolerance. In addition to benzylic positions, carbon-carbon bonds can also be constructed at allylic positions. Preliminary mechanistic studies suggest that the copper cocatalyst promotes the transmetalation of Suginome's reagent, and the addition of a PyrOx ligand inhibits the formation of side-products from the carbon-Heck pathway. Moreover, studies toward the nature of the PyrOx ligand revealed that the steric hindrance of the oxazoline moiety greatly affects the chain-walking process, but not the arylation step.

Reaction scope and mechanistic insights of nickel-catalyzed migratory Suzuki-Miyaura cross-coupling.

Cross-coupling reactions have developed into powerful approaches for carbon-carbon bond formation. In this work, a Ni-catalyzed migratory Suzuki-Miyaura cross-coupling featuring high benzylic or allylic selectivity has been developed. With this method, unactivated alkyl electrophiles and aryl or vinyl boronic acids can be efficiently transferred to diarylalkane or allylbenzene derivatives under mild conditions. Importantly, unactivated alkyl chlorides can also be successfully used as the coupling partners. To demonstrate the applicability of this method, we showcase that this strategy can serve as a platform for the synthesis of terminal, partially deuterium-labeled molecules from readily accessible starting materials. Experimental studies suggest that migratory cross-coupling products are generated from Ni(0/II) catalytic cycle. Theoretical calculations indicate that the chain-walking occurs at a neutral nickel complex rather than a cationic one. In addition, the original-site cross-coupling products can be obtained by alternating the ligand, wherein the formation of the products has been rationalized by a radical chain process.