Comparative analysis of a novel spectral-domain OCT biometer versus swept-source OCT or OLCR biometer in healthy pediatric ocular biometry.

With the advancements in ocular biometric technology, there have been significant improvements in accurately and efficiently measuring ocular parameters. The aim of this study is to compare the reliability of biometric parameters obtained using a new frequency-domain optical coherence tomography (SD-OCT) biometer with the measurements obtained from swept-source OCT (SS-OCT) and optical low coherence reflectometry (OLCR) biometers. This study employed an observational cross-sectional design. Measurements of axial length (AL), flat and steep corneal keratometry (K1 and K2), and central corneal thickness (CCT) obtained using the The Colombo IOL were compared with those obtained with the IOLMaster 700 and SW-9000 devices. The agreement were evaluated using intraclass correlation coefficient (ICC) and Bland-Altman analyses. The differences of the measurements of the three increments were assessed by one-way ANONA. 73 right eyes of 73 healthy pediatric subjects were analyzed. The AL difference measured by Colombo IOL compared with IOLmaster700 and SW-9000 were 0.00 ± 0.02 mm and - 0.07 ± 0.05 mm, respectively (P > 0.05, ANOVA). There was no statistically significant difference in CCT, K1, and K2 among the three instruments (all P > 0.05, ANOVA). The ICC values for AL, K1, K2, and CCT were 0.999, 0.996, 0.995, and 0.998, respectively. The Bland-Altman analysis showed an agreement of AL, K1, K2, and CCT with Colombo IOL and IOLMaster 700 spanned over 0.08 mm, 0.71D, 0.69D, and 12.17 µm, respectively. The agreement of AL, K1, K2, and CCT with Colombo IOL and SW-9000 spanned approximate 0.21 mm, 0.75D, 1.06D, and 14.37 µm, respectively. The new SD-OCT biometer and the SS-OCT biometer showed strong agreement in measuring AL and CCT in healthy pediatric subjects. This supports the reliability of the new SD-OCT biometer as an alternative for assessing these parameters. However, K1 and K2 could not be used interchangeably in clinical practice. Further research is needed to explore their applicability in different clinical settings and patient populations."light" />.

Reduction Polymerization of CO2 with Phenylene Silanes Cata-lyzed by Single Component B(C6F5)3.

CO2 is an abundant C1 resource but a green-house gas and chemically inert. Thus, its utilization has been a promising but challenging project. Herein, we report the unprecedented polymerization of CO2 and C6H4(SiMe2H)2 using B(C6F5)3 alone under mild conditions to give poly(silphenylene siloxane) accompanied by releasing CH4. The copolymerization can be extended to comonomers of phenylene silanes bearing functional groups. Moreover, it combines with Piers-Rubinsztajn reaction to establish a tandem polymerization system to achieve super thermal resistant poly(siloxane-co-silphenylene siloxane)s. Density functional theory reveals that B(C6F5)3 is activated by silanes to form free HB(C6F5)2, which is the true active species for CO2 reducing to borylformate, the rate controlling step of the polymerization procedure. The subsequent multiple reductions of borylformate to CH4 and the step-growth to poly(silphenylene siloxane)s can be fulfilled by both B(C6F5)3 and HB(C6F5)2, and the former shows a slightly higher activity. This work opens a new avenue of utilizing CO2 to fabricate polysiloxanes that is unable to access using current manners.

Installing a Trigger to Upcycle High-Density Polyethylene.

Creating C═C bonds as "weak" sites in the stable C-C chains of polyethylene (PE) is an appealing strategy to promote sustainable development of the polyolefin industry. Compared to methods, such as dehydrogenation and postpolymerization modification, the copolymerization of ethylene (E) and butadiene (BD) should be a convenient and direct approach to introduce C═C bonds in PE, whereas it encounters problems in controlling the composition and regularity of the copolymer due to the mismatched activities and mechanisms between the two monomers. Herein, we report by employing the amidinate gadolinium complex, controllable E/BD copolymerization was achieved, where BD was incorporated in the uniformly discrete 1,4 mode. The obtained copolymer possesses the same physical, mechanical, processing, and antioxygen (aging at 100 °C for 28 days) properties as commercial high-density-PE, which, strikingly, were degraded by C═C bonds into α,ω-telechelic oligomers with narrow distribution. These degraded functional products were transferred to compatibilizers via atom-transfer radical polymerization or immortal ring-opening polymerization, achieving upcycling.

Research on the damage and wound repair of cornea by GO and ZnO.

OBJECTIVE: The widespread use of nanoparticles in recent years has increased the risk of ocular exposure. zinc oxide (ZnO) is widely used in the field of cosmetics because of its unique chemical properties. The application of graphene oxide (GO) as an emerging nanomaterial in the field of eye drops is also gradually emerging. Currently, research on ZnO and GO eye exposure mainly focuses on application or toxicity to optic nerve cells. There's less study on corneal wound healing effects. and the previous research hasn't compared ZnO and GO corneal toxicity. METHODS: We systematically established a complete chain study of in vitro and in vivo experiments and mouse corneal injury model, and comprehensively evaluated the ocular safety and toxicity of ZnO and GO. RESULTS: We found that 50 ug/mL GO and 0.5 ug/mL ZnO can reduce human corneal epithelial cells (HCEpiC) viability in a concentration-dependent manner. Short-term repeated exposure to ZnO can cause sterile inflammation of the cornea with concentration-dependence, while GO have not been significantly altered. 50 ug/mL ZnO could significantly delay the healing of corneal wounds, while GO did not change wound healing. CONCLUSION: The toxic effect of ZnO is higher than that of GO. Inflammatory signal transduction, oxidative stress and apopnano zitosis are involved in the ocular toxicity injury process of nanoparticles. Research can provide a judgement basis for people's eye health and eye protection risk control.

Form-deprivation myopia promotes sclera M2-type macrophages polarization in mice.

PURPOSE: To explore the phenotype of sclera macrophages in form-deprivation (FD) myopia mice and the effects of M2 macrophage in FD myopia development. METHODS: C57BL/6 mice were under 2 weeks of unilateral FD treatment. and they were separated into two groups, including an intraperitoneally injected(IP) vehicle group and Panobinostat (LBH589) (10 mg/kg per body weight) treatment group. All biometric parameters were measured before and after treatments, and the type and density of sclera macrophages were identified by immunofluorescence and RT-qPCR. In vitro, we analyzed the M2 macrophage and primary human sclera fibroblast (HSF) co-culture system by using the transcriptome sequencing method. Gene ontology (GO) and KEGG enrichment analyses were used to pinpoint the biological functions and pathways associated with the identified Differentially Expressed Genes (DEGs). The hub genes were investigated using the STRING database and Cytoscape software and were confirmed using RT-qPCR. RESULTS: We found that the M2-type sclera macrophage density and expression increased in FD-treated eyes. The results showed that LBH589 inhibited the M2 macrophage polarization, and reduced FDM development. GO and KEGG analyses revealed that the DEGs were predominantly involved in the synthesis and breakdown of the extracellular matrix (ECM), as well as in pathways related to ECM-receptor interaction and the PI3K-Akt signaling pathway. Five hub genes (FN-1, MMP-2, COL1A1, CD44, and IL6) were identified, and RT-qPCR validated the variation in expression levels among these genes. CONCLUSION: M2 macrophage polarization occurred in the sclera in FDM mice. Panobinostat-mediated inhibition of M2 macrophage polarization may decrease FDM progression, as M2 macrophages are crucial in controlling ECM remodeling by HSFs.

Knowledge, attitudes, and practices toward cardiovascular complications among end-stage renal disease patients undergoing maintenance hemodialysis.

BACKGROUND: This study aimed to investigate the knowledge, attitudes, and practices (KAP) toward cardiovascular complications among end-stage renal disease patients undergoing maintenance hemodialysis. METHODS: This web-based cross-sectional study was conducted at Guangdong Provincial People's Hospital between December 2022, and May 2023. RESULTS: A total of 545 valid questionnaires were collected, with an average age of 57.72 ± 13.47 years. The mean knowledge, attitudes and practices scores were 8.17 ± 2.9 (possible range: 0-24), 37.63 ± 3.80 (possible range: 10-50), 33.07 ± 6.10 (possible range: 10-50) respectively. Multivariate logistic regression analysis showed that patients from non-urban area had lower knowledge compared to those from urban area (odds ratio (OR) = 0.411, 95% CI: 0.262-0.644, P < 0.001). Furthermore, higher levels of education were associated with better knowledge, as indicated by OR for college and above (OR = 4.858, 95% CI: 2.483-9.504), high school/vocational school (OR = 3.457, 95% CI: 1.930-6.192), junior high school (OR = 3.300, 95% CI: 1.945-5.598), with primary school and below as reference group (all P < 0.001). Besides, better knowledge (OR = 1.220, 95% CI: 1.132-1.316, P < 0.001) and higher educational levels were independently associated with positive attitudes. Specifically, individuals with a college degree and above (OR = 2.986, 95% CI: 1.411-6.321, P = 0.004) and those with high school/vocational school education (OR = 2.418, 95% CI: 1.314-4.451, P = 0.005) have more positive attitude, with primary school and below as reference group. Next, better attitude (OR = 1.174, 95% CI: 1.107-1.246, P < 0.001) and higher education were independently associated with proactive practices. Those with college and above (OR = 2.870, 95% CI: 1.359-6.059, P = 0.006), and those with high school/vocational school education (OR = 1.886, 95% CI: 1.032-3.447, P = 0.039) had more proactive practices, with primary school and below as reference group. CONCLUSIONS: End-stage renal disease patients undergoing maintenance hemodialysis demonstrated insufficient knowledge, positive attitudes, and moderate practices regarding cardiovascular complications. Targeted interventions should prioritize improving knowledge and attitudes, particularly among patients with lower educational levels and income, to enhance the management of cardiovascular complications in end-stage renal disease.

Effect of banana intake on serum potassium level in patients undergoing maintenance hemodialysis: A randomized controlled trial.

Objective: This study aimed to assess the effect of banana intake during hemodialysis on serum potassium levels in maintenance hemodialysis (MHD) patients. Methods: This study was a single-center, randomized controlled clinical trial conducted from September 15 to December 15, 2021, at a tertiary hospital in southern China. A total of 126 MHD patients were randomly assigned to either the intervention group (n = 64) or the control group (n = 62). Patients in the intervention group consumed approximately 250 g of bananas during hemodialysis, while those in the control group did not consume any food during hemodialysis. Demographic information and hemodialysis-related parameters were collected through case information collection before hemodialysis. Laboratory indicators (such as complete blood count, biochemical indicators, inflammation markers, liver function, kidney function, etc.) were evaluated by collecting pre-hemodialysis blood samples from patients. Serum potassium and blood glucose levels were measured at 2 h and 4 h of hemodialysis, as well as before the next hemodialysis session, and hemodialysis-related complications were recorded. The blood potassium and blood glucose indicators during hemodialysis were compared using repeated measures analysis. Results: A total of 122 MHD patients completed the study (61 in each group). The results showed that there was no significant interaction between group and time on serum potassium levels. However, serum potassium levels in the intervention group were higher than those in the control group at 2 h (3.9 ± 0.5 mmol/L vs. 3.6 ± 0.3 mmol/L, P < 0.01) and 4 h (3.5 ± 0.4 mmol/L vs. 3.3 ± 0.3 mmol/L, P < 0.01) of hemodialysis. There was no interaction between group and time on blood glucose levels. The incidence of arrhythmias (8.2% vs. 29.5%, P = 0.003) and hypokalemia (52.5% vs. 80.3%, P = 0.002) during hemodialysis was significantly lower in the intervention group compared to the control group. Conclusion: Consuming approximately 250 g of bananas at the start of hemodialysis does not lead to hyperkalemia. It can effectively reduce the incidence of hypokalemia and arrhythmias, and prevent a rapid decline in serum potassium levels during hemodialysis.

Morphologic and Functional Assessment of Photoreceptors in Laser-Induced Retinopathy Using Adaptive Optics Scanning Laser Ophthalmoscopy and Microperimetry.

PURPOSE: To assess the cone photoreceptors' morphology and associated retinal sensitivity in laser-induced retinopathy (LIR) using adaptive optics scanning laser ophthalmoscopy (AO-SLO) and microperimetry (MP). DESIGN: Cohort study. METHODS: This study included 13 patients (15 eyes) with LIR and 38 age-matched healthy volunteers (38 eyes). Participants underwent comprehensive evaluations including AO-SLO, MP, and spectral-domain OCT. Lesion morphology, cone density, dispersion, and regularity in AO-SLO were assessed and correlated with visual function. RESULTS: In AO-SLO images, LIR lesions were predominantly characterized by hyporeflective regions, suggesting potential cone loss at the fovea, accompanied by the presence of sizable clumps of hyperreflective material within these lesions. The average size of lesions in affected eyes was 97,128±107,478 µm², ranging from 6705 to 673,348 µm². Compared with the healthy contralateral eye and control group, LIR demonstrated significantly reduced cone density, increased cone dispersion, and notably decreased cone regularity in all 4 quadrants at 3° eccentricity (all P values < .05). Lesion morphology in AO-SLO correlated with ellipsoid zone defects observed in OCT, showing a positive correlation in size (r = 0.84, P < .001) but not with retinal sensitivities (P = .09). Similarly, cone density at 3° eccentricity did not correlate with retinal sensitivities (P = .13). CONCLUSIONS AND RELEVANCE: The study provides crucial insights into the morphologic and functional impacts of LIR on cone photoreceptors, revealing significant morphologic changes in cones that do not consistently align with functional outcomes. This research highlights the need for continued exploration into the relationship between retinal structure and function in LIR, and the importance of heightened public awareness and preventive strategies to mitigate the risk of LIR.

Up-to-date molecular medicine strategies for management of ocular surface neovascularization.

Ocular surface neovascularization and its resulting pathological changes significantly alter corneal refraction and obstruct the light path to the retina, and hence is a major cause of vision loss. Various factors such as infection, irritation, trauma, dry eye, and ocular surface surgery trigger neovascularization via angiogenesis and lymphangiogenesis dependent on VEGF-related and alternative mechanisms. Recent advances in antiangiogenic drugs, nanotechnology, gene therapy, surgical equipment and techniques, animal models, and drug delivery strategies have provided a range of novel therapeutic options for the treatment of ocular surface neovascularization. In this review article, we comprehensively discuss the etiology and mechanisms of corneal neovascularization and other types of ocular surface neovascularization, as well as emerging animal models and drug delivery strategies that facilitate its management.

Divergent Synthesis of α-(1,3,5-Triazinylthio)-ketones and Thiazolo[3,2-a][1,3,5]triazines from 1,3-Dicarbonyl compounds or Chalcones with 1,3,5-Triazine-2-thiols.

An efficient synthesis of α-(1,3,5-triazinylthio)-ketones from 1,3-dicarbonyl compounds with 1,3,5-triazine-2-thiols has been developed. The reaction proceeds through the C-C bond cleavage and C-S bond reconstruction of 1,3-dicarbonyl compounds, and ß-keto esters, ß-keto amides, and 1,3-diones were tolerated. In addition, the annulation of 1,3,5-triazine-2-thiols with chalcones has been achieved for the synthesis of thiazolo[3,2-a][1,3,5]triazines. The method occurred in moderate to good yields and tolerated chalcone with a broad functional group.

Integration of Gross Anatomy, Histology, and Pathology in a Pre-matriculation Curriculum: A Triple-Discipline Approach.

In recent years, many schools have cut back on their teaching and laboratory hours, and courses in the anatomical sciences are more integrated into the horizontal and longitudinal curriculums. Traditionally, teaching in anatomical science classes consists of lectures and laboratory sessions. Usually, gross anatomy and histology are the two main courses in pre-matriculation programs. The summer pre-matriculation program at the University of Mississippi Medical Center (UMMC) was designed to better prepare students for success in their first year of medicine and dentistry. The course provided these students with an opportunity to study gross anatomy and histology ahead of time and develop their learning skills for the coming academic year. Historically, gross anatomy and histology courses have been taught separately with a different emphasis. We have designed a new approach to implement gross anatomy, histology, and pathology-all three disciplines-in a single lecture in the organ section of the histology course. This triple-discipline (triple lecture) approach allows three professors in anatomy, histology, and pathology to work together in a two-and-a-half-hour review lecture. This approach allows students to develop their critical thinking skills and better prepares them to transfer basic anatomic knowledge into their future clinical practice. Students indicated this was their first experience with the triple-discipline approach, and they remarked that it helped them integrate anatomy and histology as well as demonstrate the clinical importance of the structures and organs. This approach can be used at different stages of medical education and helps faculty and students better integrate various disciplines and is more suitable in the modern curriculum. A similar approach was used in our fourth year course in medical histology.

Past and Current Learning and Teaching Resources and Platforms.

For over two centuries, the educational landscape both nationally and globally has changed tremendously. The more traditional teaching and learning resources and platforms, such as traditional textbooks, chalkboards and whiteboards, overhead transparency and carousel projectors, and traditional classroom settings, have been either replaced or supplemented in the anatomical sciences by integrated and virtual eBooks, online learning management (OLM) platforms, and virtual learning and meeting apps. Virtual teaching and learning, especially proliferated with the advent and aftermath of the COVID-19 pandemic, and institutions worldwide that had already been utilizing virtual class and lab sessions in their anatomy curricula expanded virtual course offerings. Many institutions have retained virtual course offerings even after the pandemic, given the distance learning benefits. The future of anatomy education holds many promising possibilities given the voracious speed with which technology is advancing. One such promising advancement is the full, seamless incorporation of virtual three-dimensional (3D) immersive and semi-immersive learning into anatomy laboratories and classroom settings globally as well as into students' laptops and handheld devices for easy use at home or anywhere.

Using Stereoscopic Virtual Presentation for Clinical Anatomy Instruction and Procedural Training in Medical Education.

This chapter begins by exploring the current landscape of virtual and augmented reality technologies in a post-pandemic world and asserting the importance of virtual technologies that improve students' learning outcomes while also reducing costs. Next, the chapter describes clinical anatomy instruction concepts in medical education, including applied anatomy content knowledge, pedagogical anatomy content knowledge, and virtual stereoscopic visualization studies that exemplify these concept areas, respectively. The chapter then explores the concept of procedural training with a specific emphasis on virtual stereoscopic anatomy visualization studies that exemplify or have implications for procedural training in medical education. Subsequently, the chapter discusses the benefits and challenges as well as the potential future positive and negative implications of virtual stereoscopic visualizations in medical education before finally concluding with some pensive considerations for the present and future of anatomy education and training using virtual technologies.

Creating Virtual Models and 3D Movies Using DemoMaker for Anatomical Education.

Three-dimensional (3D) anatomy models have been used for education in health professional schools globally. Virtual technology has become more popular for online teaching since the COVID-19 pandemic. This chapter will describe a project in which a series of virtual anatomical models of organs and structures were developed for educational purposes, and it will describe in detail how to build three-dimensional (3D) movies using DemoMaker. Although setting up the 3D system was complicated and challenging, the process of reconstructing 3D models from radiographic images and the steps of creating animations and 3D movies are exponentially simpler. These efforts require minimal training, thus allowing most people to be able to engage in this modeling process and utilize the moviemaking steps. Amira® software and computed tomographic angiography (CTA) data were used to create 3D models of the lungs, heart, liver, stomach, kidney, etc. The anatomical locations of these structures within the body can be identified and visualized by recording information from multiple CTA slices using volume and surface segmentation. Ultimately, these virtual 3D models can be displayed via dual projectors onto a specialized silver screen and visualized stereoscopically by viewers as long as they wear 3D polarized glasses. Once these 3D movies are created, they can be played automatically on a computer screen, silver screen, 3D system playback screen, and video player, and they can be embedded into PowerPoint lecture slides. Both virtual models and movies are suitable for self-directed learning, face-to-face class teaching, and virtual anatomy education. Model animations and 3D movie displays offer students the opportunities to learn about anatomy and the anatomical positions of organs in the body and their 3D relationships to one another. By observing and studying these 3D models, students have the potential to be able to compartmentalize the anatomical information and retain it at a higher level than students learning corresponding anatomy without similar resources.

Selective Synthesis of N-[1,3,5]Triazinyl-α-Ketoamides and N-[1,3,5]Triazinyl-Amides from the Reactions of 2-Amine-[1,3,5]Triazines with Ketones.

In this study, we report a selective approach for synthesizing N-([1,3,5]triazine-2-yl) α-ketoamides and N-([1,3,5]triazine-2-yl) amides from ketones with 2-amino[1,3,5]triazines through oxidation and oxidative C-C bond cleavage reaction, respectively. The transformation proceeds under mild conditions, provides good functional group tolerance and chemoselectivity, and will serve as a valuable tool for the synthesis of bioactive products.

Role of 7-methylxanthine in myopia prevention and control: a mini-review.

Myopia is becoming increasingly common. By 2050 around 10% of the world's population is expected to be highly myopic (<-5 diopters) and therefore particularly at risk of suffering from sight-threatening complications. Currently used myopia control treatments, such as multifocal soft contact lenses or spectacle lenses, orthokeratology, and atropine eyedrops, either do not completely arrest myopia progression or are associated with significant ocular and possibly systemic side effects. A new candidate for pharmaceutical control of myopia progression and excessive eye elongation, the non-selective adenosine antagonist 7-methylxanthine (7-MX), appears to be non-toxic and effective in reducing myopia progression and axial eye growth in experimental and clinical studies. The latest findings regarding 7-MX for myopia control and evaluate its potential as a supplement to existing treatment options were reviewed.

A core syllabus for histology within the medical curriculum - The cardiovascular and lymphoid systems, the respiratory and digestive systems, and the integument.

Medical courses worldwide are undergoing significant curricular changes, including the teaching and learning of histology. In order to set international standards for the anatomical sciences, the International Federation of Associations of Anatomists (IFAA) is developing core anatomical syllabuses by means of Delphi panels. Already published is a core syllabus for the teaching of the cell and the basic tissues within medicine. Here, we record the deliberations of an IFAA Delphi panel commissioned to develop core subject matter for the teaching within a medical histology course of the cardiovascular and lymphatic circulatory system, the lymphoid, respiratory, and digestive systems, and the integument. The Delphi panel was comprised of academics from multiple countries who were required to review relevant histological topics/items by evaluating each topic as being either "Essential," "Important," "Acceptable," or "Not required." Topics that were rated by over 60% of the panelists as being "Essential" are reported in this paper as being core topics for the teaching of medical histology. Also reported are topics that, while not reaching the threshold for being designated as core material, may be recommended or not required within the curriculum.

One-year Efficacy of the Defocus Incorporated Multiple Segment Lens in Chinese Myopic Children.

SIGNIFICANCE: These data demonstrate that defocus incorporated multiple segment (DIMS) lens reduces myopia progression in children during the first year of use. PURPOSE: This study aimed to investigate the efficacy of DIMS myopia control spectacle lens in Chinese myopic children aged 6 to 15 years. METHODS: This is a retrospective study of 1-year longitudinal data. A total of 180 Chinese myopic children were selected from patients at Zhongshan Ophthalmic Center, Sun Yat-sen University, from February 2018 to January 2021. One group consisted of 90 children aged 6 to 15 years, with spherical equivalent refraction -0.50 to -7.75 D (-3.82 ± 1.57 D) and fitted with the DIMS lens. The other group consisted of 90 children fitted with single-vision spectacle lenses and matched with the DIMS group for age, sex, refraction, and progression of myopia in the previous year. One-year myopia progression was measured retrospectively in two groups. Unpaired t test was used to compare the myopia progression between the DIMS group and the control group. Pearson correlation was used to explore the relationship between myopia progression, age, and baseline refraction. RESULTS: After 1 year of DIMS lens wear, myopia progression was significantly lower in the DIMS group (-0.51 ± 0.50 vs. -0.85 ± 0.51 D, P < .001). Myopia progression was positively correlated with age in both groups. The difference between the DIMS and control groups was more pronounced for children aged 10 to 15 years than for children aged 6 to 9 years. CONCLUSIONS: This study confirms that the DIMS lens reduces myopia progression during the first year of use. Efficacy seems to increase with age.

Lewis Acids Activated Spontaneous Alternating Copolymerization of Maleic Anhydride and Styrene Derivatives.

Synthesis of maleic anhydride (MA) and styrene (St) copolymers possessing ultra-high molecular weight, strictly alternating regularity and high glass transition temperature simultaneously is still an issure with great challenge. Herein, the spontaneous alternating copolymerization of MA and St derivatives were investigated by using various Lewis acids. In the presence of alkyl aluminum or butyl magnesium, the MA-St alternating copolymers with ultra-high molecular weight (Mn ≤166.5×104 ) and high glass transition temperature (211 °C≤Tg ≤216 °C) were produced and the microstructure of MA-St copolymers were analyzed by 1 H and 13 C NMR spectra. The copolymerizations of MA with St derivatives, including divinylbenzene, p-butenyl styrene, p-methoxystyrene, trans-anethole, p-fluorostyrene and p-chlorostyrene, also were explored by using AlOctyl3 as an activator in toluene at 50 °C.

Access to Disentangled Ultrahigh Molecular Weight Polyethylene via a Binuclear Synergic Effect.

Disentangled ultrahigh molecular weight polyethylene (dis-UHMWPE) has excellent processability but can be achieved under extreme conditions. Herein, we report ethylene polymerization with the binuclear half-sandwich scandium complexes C1-Sc2 and C2-Sc2 to afford UHMWPE. C1-Sc2 bearing a short linker shows higher activity and gives higher molecular weight PEs than C2-Sc2 containing a flexible spacer and the mononuclear Sc1 . Strikingly, all UHMWPEs isolated from C1-Sc2 under broad temperature range (25-120 °C) and wide ethylene pressures (2-13 bar) feature very low degree of entanglement as proved by rheological test, DSC annealing study and SEM. These dis-UHMWPEs are facilely mediated solid-state-process at 130 °C and their tensile strength and modulus reach up to 149.2 MPa and 1.5 GPa, respectively. DFT simulations reveal that the formation of dis-UHMWPE is attributed to the binuclear synergic effect and the agostic interaction between the active center and the growing chain.