Age estimates for hominin fossils and the onset of the Upper Palaeolithic at Denisova Cave.

Denisova Cave in the Siberian Altai (Russia) is a key site for understanding the complex relationships between hominin groups that inhabited Eurasia in the Middle and Late Pleistocene epoch. DNA sequenced from human remains found at this site has revealed the presence of a hitherto unknown hominin group, the Denisovans1,2, and high-coverage genomes from both Neanderthal and Denisovan fossils provide evidence for admixture between these two populations3. Determining the age of these fossils is important if we are to understand the nature of hominin interaction, and aspects of their cultural and subsistence adaptations. Here we present 50 radiocarbon determinations from the late Middle and Upper Palaeolithic layers of the site. We also report three direct dates for hominin fragments and obtain a mitochondrial DNA sequence for one of them. We apply a Bayesian age modelling approach that combines chronometric (radiocarbon, uranium series and optical ages), stratigraphic and genetic data to calculate probabilistically the age of the human fossils at the site. Our modelled estimate for the age of the oldest Denisovan fossil suggests that this group was present at the site as early as 195,000 years ago (at 95.4% probability). All Neanderthal fossils-as well as Denisova 11, the daughter of a Neanderthal and a Denisovan4-date to between 80,000 and 140,000 years ago. The youngest Denisovan dates to 52,000-76,000 years ago. Direct radiocarbon dating of Upper Palaeolithic tooth pendants and bone points yielded the earliest evidence for the production of these artefacts in northern Eurasia, between 43,000 and 49,000 calibrated years before present (taken as AD 1950). On the basis of current archaeological evidence, it may be assumed that these artefacts are associated with the Denisovan population. It is not currently possible to determine whether anatomically modern humans were involved in their production, as modern-human fossil and genetic evidence of such antiquity has not yet been identified in the Altai region.

Two {CuI[P4Mo6]2}-Based Coordination Polymers Incorporating In Situ Converted Tetrapyridyl Ligands for Trace Analysis of Nitrofuran Antibiotics.

Nitrofurans are important synthetic broad-spectrum antibacterial drugs with the basic structure of 5-nitrofuran. Due to their toxicity, it is essential to develop a sensitive sensor with strong anti-interference capabilities for their detection. In this work, two {P4Mo6O31}12--based compounds, [H4(HPTTP)]2{CuI[Mo12O24(OH)6(PO4)3(HPO4)(H2PO4)4]}·xH2O (x = 13 for (1), 7 for (2); HPTTP = 4,4',4″,4‴-(1H-pyrrole-2,3,4,5-tetrayl)tetrapyridine), exhibiting similar coordination but distinct stacking modes. Both compounds were synthesized and used for the electrochemical detection of nitrofuran antibiotics. The tetrapyridine-based ligand was generated in situ during assembly, and its potential mechanism was discussed. Composite electrode materials, formed by mixing graphite powder with compounds 1-2 and physically grinding them, proved to be highly effective in the electrochemical trace detection of furazolidone (FZD) and furaltadone hydrochloride (FTD·HCl) under optimal conditions. Besides, the possible electrochemical detection mechanisms of two nitro-antibiotics were studied.

Core@Double-Shell Engineering of Zn Particles toward Elevated Dielectric Properties: Multiple Polarization Mechanisms in Zn@Znch@PS/PVDF Composites.

Flexible dielectrics with large dielectric constant (ε') coupled with low loss are highly pursued in many applications. To bolster the ε' of raw Zn (zinc)/poly(vinylidene fluoride, PVDF) while maintaining pimping dielectric loss, in this study, the core@double-shell structured Zn@zinc carbonate (ZnCH)@polystyrene (PS) particles are first synthesized through a suspension polymerization of styrene, and then composited with PVDF to elevate the ε' and keep low loss of the composites. By optimizing the PS shells' thickness and tailoring the electrical resistivity of Zn@ZnCH@PS particles, both the slow inter-particle polarization and fast intra-particle polarization in the composites can be decoupled and synergistically tuned, thus, the Zn@ZnCH@PS/PVDF achieves a much higher ε' and lower dielectric loss, simultaneously, which far exceed the unmodified Zn/PVDF. Both experiment and theoretic calculation reveal that the double-shell ZnCH@PS not only induces and promotes multiple polarizations enhancing the composites' ε', especially at the optimized PS's thickness, but also maintains suppressed loss and conductivity thanks to their obvious barrier effect on long-range charge migration. The core@double-shell filler design strategy facilitates the development of polymer composites with desirable dielectric properties for applications in electronic and electrical power systems.

Infection microenvironment-triggered nanoparticles eradicate MRSA by thermally amplified chemodynamic therapy and M1 macrophage.

It is of great significance to develop a novel approach to treat bacterial infections, as the frequent misuse of antibiotics leads to the serious problem of bacterial resistance. This study proposed antibiotic-free antibacterial nanoparticles for eliminating methicillin-resistant Staphylococcus aureus (MRSA) based on a multi-model synergistic antibacterial ability of chemodynamic therapy (CDT), photothermal effect, and innate immunomodulation. Specifically, a polydopamine (PDA) layer coated and Ag nanoparticles loaded core-shell structure Fe3O4 nanoparticles (Fe3O4@PDA-Ag) is prepared. The Fe3O4 catalyzes H2O2 present in acidic microenvironment of bacterial infection into more toxic reactive oxygen species (ROS) and synergizes with the released Ag ions to exert a stronger bactericidal capacity, which can be augmented by photothermal action of PDA triggered by near-infrared light and loosen the biofilm by photothermal action to promote the penetration of ROS and Ag ion into the biofilm, result in disrupting biofilm structure along with killing encapsulated bacteria. Furthermore, Fe3O4@PDA-Ag exerts indirect antibacterial effects by promoting M1 macrophage polarizing. Animal models demonstrated that Fe3O4@PDA-Ag effectively controlled MRSA-induced infections through photothermal enhanced CDT, Ag+ releasing, and macrophage-mediated bactericidal properties. The acid-triggered antibacterial nanoparticles are expected to combat drug-resistant bacteria infection.

Targeted degradation of KRAS protein in non-small cell lung cancer: Therapeutic strategies using liposomal PROTACs with enhanced cellular uptake and pharmacokinetic profiles.

The role of KRAS mutation in non-small cell lung cancer (NSCLC) initiation and progression is well-established. However, "undruggable" KRAS protein poses the research of small molecule inhibitors a significant challenge. Addressing this, proteolysis-targeting chimeras (PROTACs) have become a cutting-edge treatment method, emphasizing protein degradation. A modified ethanol injection method was employed in this study to formulate liposomes encapsulating PROTAC drug LC-2 (LC-2 LPs). Precise surface modifications using cell-penetrating peptide R8 yielded R8-LC-2 liposomes (R8-LC-2 LPs). Comprehensive cellular uptake and cytotoxicity studies unveiled that R8-LC-2 LPs depended on concentration and time, showcasing the superior performance of R8-LC-2 LPs compared to normal liposomes. In vivo pharmacokinetic profiles demonstrated the capacity of DSPE-PEG2000 to prolong the circulation time of LC-2, leading to higher plasma concentrations compared to free LC-2. In vivo antitumor efficacy research underscored the remarkable ability of R8-LC-2 LPs to effectively suppress tumor growth. This study contributed to the exploration of enhanced therapeutic strategies for NSCLC, specifically focusing on the development of liposomal PROTACs targeting the "undruggable" KRAS protein. The findings provide valuable insights into the potential of this innovative approach, offering prospects for improved drug delivery and heightened antitumor efficacy.

The Effecting Mechanisms of 100 nm Sized Polystyrene Nanoplastics on the Typical Coastal Alexandrium tamarense.

Due to the increase in nanoplastics (NPs) abundance in aquatic environments, their effects on phytoplankton have aroused large research attention. In this study, 100 nm sized polystyrene NPs were chosen to investigate their effecting performance and mechanisms on a typical dinoflagellates Alexandrium tamarense. The results indicated the population growth and photosynthetic efficiencies of A. tamarense were significantly inhibited by NPs exposure, as well as the increase in cellular total carotenoids and paralytic shellfish toxins (PSTs). Meanwhile, the cellar ROS levels increased, corresponding to the increased activities or contents of multiple antioxidant components, including SOD, CAT, GPX, GR, GSH and GSSG. The transcriptional results support the physiological-biochemical results and further revealed the down-regulation of genes encoding the light reaction centers (PSI and PSII) and up-regulation of genes encoding the antioxidant components. Up-regulation of genes encoding key enzymes of the Calvin cycle and glycolytic pathway together with the TCA cycle could accelerate organic carbon and ATP production for A. tamarense cells resistant to NPs stress. Finally, more Glu and acetyl-CoA produced by the enhanced GSH cycle and the glycolytic pathway, respectively, accompanied by the up-regulation of Glu and Arg biosynthesis genes supported the increase in the PST contents under NPs exposure. This study established a data set involving physiological-biochemical changes and gene information about marine dinoflagellates responding to NPs, providing a data basis for further evaluating the ecological risk of NPs in marine environments.

[Research advances of biomedical polymeric microneedles for non-transdermal local drug delivery].

Microneedles have emerged as the new class of local drug delivery system that has broad potential for development. Considering that the microneedles can penetrate tissue barriers quickly, and provide localized and targeted drug delivery, their applications have gradually expanded to non-transdermal drug delivery recently, which are capable of providing rapid and effective treatment for injuries and diseases of organs or tissues. However, a literature search revealed that there is a lack of summaries of the latest developments in non-transdermal drug delivery research by using biomedical polymeric microneedles. The review first described the materials and fabrication methods for the polymeric microneedles, and then reviewed a representative application of microneedles for non-transdermal drug delivery, with the primary focus being on treating and repairing the tissues or organs such as oral cavity, ocular tissues, blood vessels and heart. At the end of the article, the opportunities and challenges associated with microneedles for non-transdermal drug delivery were discussed, along with its future development, in order to provide reference for researchers in the relevant field.

Synthesis, Morphology, and Crystallization Kinetics of Polyheptalactone (PHL).

Aliphatic polyesters are widely studied due to their excellent properties and low-cost production and also because, in many cases, they are biodegradable and/or recyclable. Therefore, expanding the range of available aliphatic polyesters is highly desirable. This paper reports the synthesis, morphology, and crystallization kinetics of a scarcely studied polyester, polyheptalactone (PHL). First, we synthesized the η-heptalactone monomer by the Baeyer-Villiger oxidation of cycloheptanone before several polyheptalactones of different molecular weights (in the range between 2 and 12 kDa), and low dispersities were prepared by ring-opening polymerization (ROP). The influence of molecular weight on primary nucleation rate, spherulitic growth rate, and overall crystallization rate was studied for the first time. All of these rates increased with PHL molecular weight, and they approached a plateau for the highest molecular weight samples employed here. Single crystals of PHLs were prepared for the first time, and hexagonal-shaped flat single crystals were obtained. The study of the crystallization and morphology of PHL revealed strong similarities with PCL, making PHLs very promising materials, considering their potential biodegradable character.

Source or sink role of an urban lake for microplastics from Guangdong-Hong Kong-Macao greater bay area, China.

Plastic production and consumption in China are larger than others in the world, and the challenge of microplastic pollution is widespread. With the development of urbanization in the Guangdong-Hong Kong-Macao Greater Bay Area, China, the environmental pollution of microplastics is becoming an increasingly prominent issue. Here, the spatial and temporal distribution characteristics, sources, and ecological risks of microplastics were analyzed in water from an urban lake, Xinghu Lake, as well as the contribution of rivers. Importantly, the roles of urban lakes for microplastics were demonstrated through the investigations of contributions and fluxes for microplastic in rivers. The results showed that the average abundances of microplastics in water of Xinghu Lake were 4.8 ± 2.2 and 10.1 ± 7.6 particles/m3 in wet and dry seasons, and the average contribution degree of the inflow rivers was 75%. The size of microplastics in water from Xinghu Lake and its tributaries was concentrated in the range of 200-1000 µm. In general, the average comprehensive potential ecological risk indexes of microplastics in water were 247 ± 120.6 and 273.1 ± 353.7 in wet and dry seasons, which the high ecological risks of them were found through the adjusted evaluation method. There were also mutual effects among microplastic abundance, the concentrations of total nitrogen and organic carbon. Finally, Xinghu Lake has been a sink for microplastics both in wet and dry seasons, and it would be a source of microplastics under the influence of extreme weather and anthropogenic factors.

Safety and Efficacy of Polyetheretherketone (PEEK) Cages and Cadaveric Allografts in Transforaminal Lumbar Interbody Fusion (TLIF) for Treating Lumbar Pyogenic Spondylodiscitis.

Purpose: There have been many studies in the operative management of pyogenic spondylodiscitis with foreign materials. However, it still remains an issue of debate on whether the allografts may be used in pyogenic spondylodiscitis. This study sought to evaluate the safety and effectiveness of PEEK cages and the cadaveric allograft in transforaminal lumbar interbody fusion (TLIF) for treating lumbar pyogenic spondylodiscitis. Methods: From January 2012 to December 2019, 56 patients underwent surgery for lumbar pyogenic spondylodiscitis. The posterior debridement of all patients and their fusion with allografts, local bone grafts, and bone chip cages were performed before posterior pedicle screw fusion. An assessment of the residual pain, the grade of neurological injury, and the resolution of infection was conducted on 39 patients. The clinical outcome was evaluated using a visual analog scale (VAS) and the Oswestry Disability Index (ODI), and neurological outcomes were appraised based on Frankel grades. The radiological outcomes were evaluated via focal lordosis, lumbar lordosis, and the state of the fusion. Results: Staphylococcus aureus and Staphylococcus epidermidis were the most common causative organisms. The mean preoperative focal lordosis was -1.2° (-11.4° to 5.7°), and the mean postoperative focal lordosis increased to 10.3° (4.3°-17.2°). At the final follow-up, there were five cases with subsidence of the cage, no case of recurrence, and no case with cage and screw loosening or migration. The mean preoperative VAS and ODI scores were 8.9 and 74.6%, respectively, and improvements in VAS and ODI were 6.6 ± 2.2 and 50.4 ± 21.3%, respectively. The Frankel grade D was found in 10 patients and grade C in 7. Following the final follow-up, only one patient improved from Frankel grade C to grade D while the others recovered completely. Conclusion: The PEEK cage and cadaveric allograft combined with local bone grafts is a safe and effective choice for intervertebral fusion and restoring sagittal alignment without increased incidence of relapse for treating lumbar pyogenic spondylodiscitis.

Analysis of Online Recruitment Intention Among 543 Hospitals: A Comprehensive Investigation of Influencing Factors and Current Situation.

Objective: The primary objective of this study was to investigate the current state of online recruitment intention among hospitals and identify its key influencing factors. This research aims to provide valuable insights that can guide the development of recruitment and employment strategies for hospital departments and student management. Methods: This study employed a cross-sectional survey approach involving 543 hospitals. Data collection utilized both convenient offline recruitment methods and online recruitment information platforms. A total of 543 questionnaires were distributed, resulting in the collection of 543 valid responses. The participating hospitals comprised 225 tertiary hospitals and 318 secondary hospitals. Additionally, the sample included 430 general hospitals, 113 psychiatric hospitals, dental hospitals, and 406 specialized hospitals. Geographically, 137 hospitals were located in urban counties or towns. Furthermore, 333 hospitals targeted undergraduate graduates, while 210 focused on graduate students. Results: The analysis of the data revealed several significant findings. Among the included hospitals in the sample, 19.71% expressed online recruitment intention for candidates with neurasthenia. Factors contributing to a higher online recruitment intention among hospitals included a preference for recruiting undergraduates (P = .011), the belief that online recruitment is suitable for clinical positions (P = .002), challenges in assessing candidates' expertise online (P = .002), concerns about dishonesty in online recruitment (P = .028), and the perception that online recruitment requires less technical expertise for hospitals (P < .001). Conclusions: This study highlights the multifaceted nature of online recruitment intention within hospitals. The identified influential factors emphasize the need for customized strategies in recruitment and employment. Medical university recruitment and employment departments should adopt tailored measures that align with the unique dynamics of online recruitment to address these factors effectively. In this way, hospitals can enhance their recruitment processes and ensure the selection of candidates that meet their specific requirements.

An arbuscular mycorrhizal fungus differentially regulates root traits and cadmium uptake in two maize varieties.

Arbuscular mycorrhizal fungi (AMF) are symbiotic fungi that colonize plant roots, and they are more common in Cd-polluted habitats. However, there is limited understanding of the response of root traits and cadmium (Cd) uptake to AMF in different crop varieties. Two maize varieties, Panyu 3 and Ludan 8, with high and low Cd uptake capacities, respectively, were cultivated as host plants in a pot experiment with Cd-polluted soil (17.1 mg/kg Cd). The effects of AMF on the growth, mineral nutrient concentration, root traits, phytohormone concentrations and Cd uptake of the two maize varieties and their comprehensive response to AMF fungal inoculation were investigated. AMF improved growth, mineral nutrient levels and root morphology and increased lignin and phytohormone concentrations in roots and Cd uptake in the two maize varieties. However, the two maize varieties, Panyu 3 and Ludan 8, had different responses to AMF, and their comprehensive response indices were 753.6% and 389.4%, respectively. The root biomass, branch number, abscisic acid concentrations, lignin concentrations and Cd uptake of maize Panyu 3 increased by 151.1%, 28.6%, 139.7%, 99.5% and 84.7%, respectively. The root biomass, average diameter, auxin concentration, lignin concentration and Cd uptake of maize Ludan 8 increased by 168.7%, 31.8%, 31.4%, 41.7% and 136.7%, respectively. Moreover, Cd uptake in roots presented very significant positive correlations with the average root diameter and abscisic acid concentration. A structural equation model indicated that the root abscisic acid concentration and root surface area had positive effects on Cd uptake by the Panyu 3 maize roots; the root abscisic acid concentration and root tip number had positive effects on Cd uptake by the Ludan 8 maize roots. Thus, AMF differentially regulated Cd uptake in the two maize varieties, and the regulatory effect was closely related to root traits and phytohormone concentrations.

Mass Production of Hierarchically Designed Engine-Intake Air Filters by Multinozzle Electroblow Spinning.

Particulate matter damages engines of vehicles when blown into the ventilation system. Conventional engine-intake filter is cellulose microfiber board with an average diameter larger than ten microns, which has low removal efficiency of ultrafine particular matter. In this work, we apply ultrafine polyurethane nanofibers (∼122.8 nm) onto pleated cellulose board using scalable multinozzle electroblow spinning technology, which improves filtration efficiency of particulate matter with a diameter of less than 0.3 µm PM0.3 greatly. The thermoplastic polyurethane 85A nanofiber membranes are transparent, and display superior filtration performance which meets up with the 95% filtration efficiency standard in GB 19083-2010 technical requirements for protective face mask for medical use. The lightweight pleated thermoplastic polyurethane/cellulose composites intercept ∼90% ultrafine PM0.3 under airflow velocity of 32 L min-1 and possess great resistance to shock. These hierarchically designed filters follow a mechanical mechanism and can be used in on-road and off-road cars in the long run.

A bioinspired, electroactive colorable and additive manufactured photonic artificial muscle.

Structural coloration in biomimetic nanostructures has remarkable application potential in vivid display devices, but their color change effect is still insufficiently competitive towards biology. Inspired by the feather color change of a hummingbird, a new methodology for coloration is proposed. A structure-colorable flexural artificial muscle (FlexAM) is developed by integrating a view-angle dependent photonic diffraction grating pattern and voltage-actuated dielectric elastomers as an electroactive entity via laminated object additive manufacturing. A multi-physics model is developed which guides the FlexAM to harness the view-angle dependence for the new coloration strategy. The electro-mechanochromic performances are experimentally characterized to verify the prediction of the multi-physics model. An ultrafast coloration in the FlexAM with an advancing figure-of-merit at a color-shift rate of 2.814 nm ms-1 is realized, in addition to an excellent fatigue resistance up to 10 000 cycles. A photonic display with arrayed FlexAM elements is designed, which can be used to display numbers and letters. The current research offers an advanced artificial muscle towards active photonic and visible strain sensing.

The Effects of Bone Cement Volume in Percutaneous Vertebroplasty for Thoracolumbar Junction Vertebral Compression Fractures: A Clinical Comparative Study.

We compared the outcomes of patients treated with different volumes of polymethyl methacrylate bone cement during percutaneous vertebroplasty (PVP) for thoracolumbar vertebral compression fractures. We performed a comparative, retrospective study of 316 patients who underwent PVP for a single-level thoracolumbar vertebral compression fracture. Patients were divided into two groups: group A (≤5 mL; n = 146) and group B (>5 mL; n = 170). The visual analogue scale (VAS) for pain and the Roland-Morris Disability Questionnaire (RDQ) scores were compared between the two groups at 1 week and at 1, 6, 12, and 24 months after PVP. The incidence of cement leakage into the intervertebral discs was evaluated by a postoperative lateral radiograph assessment. Patients were evaluated for new fractures 1 and 2 years after PVP or when new fractures were suspected. Among the 316 patients enrolled, 245 completed the clinical research. No difference between groups A and B in terms of the VAS, RDQ, and rate of complications at all time points after surgery was observed. The presence of intervertebral disc leakage was a relative risk (RR) for subsequent total vertebral fracture (RR, 6.42; 95% confidence interval (CI), 2.72-14.19; P < 0.0001) and adjacent vertebral fracture (RR, 8.03; 95% CI, 2.74-23.54; P = 0.0001). A high volume of bone cement may increase the rate of subsequent total and adjacent vertebral fractures. However, the occurrence of intervertebral disc leakage is the principal risk factor for these negative outcomes of PVP.

Prognostic factors and related complications/sequalae of squamous cell carcinoma located in the gingivobuccal complex.

BACKGROUND: Gingivobuccal complex (GBC) was a relatively new concept of oral subsite that was comprises of the upper and/or lower gingiva, gingival buccal sulcus, and adjacent buccal mucosa. Squamous cell carcinoma (SCC) of the GBC had a poor prognosis, with few studies analyzing this particular entity. The objective of this study was to analyze the risk factors affecting the prognosis and complications/sequalae of gingivobuccal complex cancer. METHODS: Between December 2014 and August 2019, a total of 122 patients diagnosed with primary gingivobuccal complex cancer in Beijing Stomatological Hospital, Capital Medical University were enrolled in the study. Through outpatient reviewed and telephone followed-up for 2-5 years postoperatively, postoperative relapse and complications/sequalae were assessed. The primary outcome parameter was 2-year disease-free survival. RESULTS: The most common central site of the tumor was the buccal mucosa (45.1%), followed by the lower gingiva (36.9%). The most diseases were pT4a (45.1%) and there was lymph node invasion (pN+) in 41.8% of patients. Moderate differentiated squamous carcinoma (77.9%) accounted for the vast majority of the histopathological differentiation. A total of 62.3% of tumors invaded the bone, while, 5.7% invaded the skin layer. Survival analysis found that 44.3% of patients experienced relapse within two years postoperatively and the mortality rate after relapse was 75.9%. Almost 60.0% of the tumors involving the maxilla and/or mandible developed relapse. Cox proportional hazards model found that pN stage (p= 0.002) and bone invasion (p= 0.007) were significant independent predictors of 2-year disease-free survival. Importantly, 63.1% of patients had postoperative (and postradiotherapy) complications/sequalae. It was noteworthy that 18 of 43 patients (41.9%) who implanted with titanium plates had hardware-related complications/sequalae, and the most of them were titanium plate exposure (61.1%). CONCLUSIONS: Squamous cell carcinoma of the gingivobuccal complex cancer, as a new subsite worthy of attention in oral cancer, has a high complication/sequalae rate, high relapse rate and poor prognosis. TRIAL REGISTRATION: Prospective, Observational, Real-world Oral Malignant Tumors Study ( clinicaltrials.gov identifier: NCT02395367). The approval of the Institutional Review Board of the Beijing Stomatological Hospital of Capital Medical University (Approval number: CMUSH-IRB-KJPJ-2015-08).

3D-printed hemipelvic prosthesis combined with a dual mobility bearing in patients with primary malignant neoplasm involving the acetabulum: clinical outcomes and finite element analysis.

BACKGROUND: Limb salvage reconstruction for pelvic tumors, especially periacetabular tumors, is challenging. We combined the use of dual mobility bearing and 3D-printed hemipelvic prosthesis to improve function and reduce the probability of complications after hemi-pelvic resection in patients with primary acetabular malignancy. The purpose of this study was to evaluate the efficacy and safety of this combination. METHODS: Between October 2011 and May 2021, 11 patients with malignancies involving the acetabulum received hemipelvic replacement with a 3D-printed prosthesis and dual mobility bearing. Follow-up of postoperative survival, complications, and Musculoskeletal Tumor Society 93 (MSTS-93) lower limb functional scores were carried out. A finite element model of the postoperative pelvis was developed and input into the finite element analysis software. The Von Mises equivalent stress formula was used to analyze the stress distribution of each part of the pelvis under one gait cycle and the stress distribution at different angles of the hip joint. RESULTS: By the last follow-up, 9 of the 11 patients (81.8%) were still alive, and 2 patients had local tumor recurrence. The complications including 1 deep infection and 1 dislocation of the artificial joint. Excluding 1 amputation patient, the average score of the remaining 8 patients at the last follow-up was 21.4/30 (71.3%) on the MSTS-93. In the reconstructed pelvis, stress distributions were concentrated on the junction between hemipelvic prosthesis and screw and iliac bone on the resected side, and between femoral prosthesis stem and femoral bulb, while the stress of polyethylene lining was small. Before impact, the polyethylene lining will rotate at a small angle, about 3°. The inner stress of polyethylene liner is greater than the outer stress in all conditions. The polyethylene liner has no tendency to slide out. CONCLUSION: Pelvic tumor resection and reconstruction using 3D-printed hemipelvic prosthesis combined with dual mobility bearing was an effective treatment for pelvic tumors. Our patients achieved good early postoperative efficacy and functional recovery. The dual mobility bearing is beneficial to prevent dislocation, and the mechanical distribution and wear of the prosthesis are acceptable.

Ophthalmology as a career choice among medical students: a survey of students at a Canadian medical school.

BACKGROUND: There is a lack of investigations into the factors that lead medical students to pursue increasingly competitive post-graduate training programs. We sought to determine the factors that influence medical students' opinions on ophthalmology as a career and on ophthalmological medical education. METHODS: An anonymous 36-question survey was distributed to all medical students across the four program years at the Schulich School of Medicine and Dentistry as a non-probabilistic convenience sample. Survey results were analyzed using Mann-Whitney U tests to determine significant differences between study sub-populations. Multivariate regression analysis was performed to identify correlates for positive views towards ophthalmology. RESULTS: 81% of questions had a mean positive response amongst the students. Students held negative views regarding the amount of exposure to ophthalmology in medical school. The greatest differences in opinion regarding ophthalmology were seen between those with more exposure and interest in ophthalmology compared to their counterparts with less. Regression analysis identified interest in ophthalmology as a significant correlate to a positive opinion in the field. CONCLUSIONS: Our survey demonstrates that while most students had positive views about ophthalmology, some aspects were viewed negatively. Students felt there was a lack of exposure, both educationally and clinically to ophthalmology, which may contribute to some misconceptions of the field. Early exposure appeared to be critical to forming positive opinions of ophthalmology and could be emphasized in medical education.

Artificial Water Channels: Towards Biomimetic Membranes for Desalination.

Natural Aquaporin (AQP) channels are efficient water translocating proteins, rejecting ions. Inspired by this masterpiece of nature, Artificial Water Channels (AWCs) with controlled functional structures, can be potentially used to mimic the AQPs to a certain extent, offering flexible avenues toward biomimetic membranes for water purification. The objective of this paper is to trace the historical development and significant advancements of current reported AWCs. Meanwhile, we attempt to reveal important structural insights and supramolecular self-assembly principles governing the selective water transport mechanisms, toward innovative AWC-based biomimetic membranes for desalination.

Decellularized matrix could affect the proliferation and differentiation of periodontal ligament stem cells in vitro.

OBJECTIVE AND BACKGROUND: Recently, decellularized matrix (DCM) is considered as a new biomaterial for tissue regeneration. To explore the possible application of DCM in periodontal regeneration, the effect of DCM from three different cells on the proliferation and differentiation of human periodontal ligament stem cells (PDLSCs) was investigated. METHODS: DCM derived from human periodontal ligament cells (PDLCs), dental pulp cells (DPCs), and gingival fibroblasts (GFs) were fabricated using Triton X-100/NH4 OH combined with DNase I. Allogeneic PDLSCs were cultured on PDLC-DCM, DPC-DCM, and GF-DCM, respectively. The proliferative capacity of PDLSCs was evaluated by PicoGreen assay kit. The expression of alkaline phosphatase (ALP), runt-related transcription factor-2 (RUNX2), osteocalcin (OCN), collagen I (COL1), periostin (POSTN), and cementum protein 1 (CEMP1) were detected by qRT-PCR and western blotting. RESULTS: PDLC-DCM, DPC-DCM, and GF-DCM had similar and integrated networks of extracellular matrix, as well as significantly decreased DNA content. Compared with control group in which PDLSCs were directly seeded in culture plates, PDLC-DCM, DPC-DCM, and GF-DCM promoted the proliferation of re-seeded PDLSCs. Additionally, PDLSCs on DCM exhibited higher mRNA and protein expression levels of ALP, RUNX2, OCN, and COL1. The expression of POSTN in PDLC-DCM group was significantly higher than control group at both mRNA and protein levels. CONCLUSIONS: PDLC-DCM, DPC-DCM, and GF-DCM could enhance the proliferation of PDLSCs. PDLC-DCM facilitated osteogenic differentiation and periodontal ligament differentiation of PDLSCs, while DPC-DCM and GF-DCM promoted osteogenic differentiation.