Biomechanical investigation of the hybrid modified cortical bone screw–pedicle screw fixation technique: Finite-element analysis

BackgroundHybrid fixation techniques including the both modified cortical bone trajectory (MCBT) and traditional trajectory (TT) at the L4 and L5 lumbar segment are firstly proposed by our team. Therefore, the purpose of this study is to evaluate and provide specific biomechanical data of the hybrid fixation techniques including the MCBT and TT.MethodsFour human cadaveric specimens were from the anatomy laboratory of Xinjiang Medical University. Four finite-element (FE) models of the L4–L5 lumbar spine were generated. For each of them, four implanted models with the following fixations were established: TT-TT (TT screw at the cranial and caudal level), MCBT-MCBT (MCBT screw at the cranial and caudal level), hybrid MCBT-TT (MCBT screw at the cranial level and TT screw at the caudal level), and TT-MCBT (TT screw at the cranial level and MCBT screw at the caudal level). A 400-N compressive load with 7.5 N/m moments was applied to simulate flexion, extension, lateral bending, and rotation, respectively. The range of motion (ROM) of the L4–L5 segment and the posterior fixation, the von Mises stress of the intervertebral disc, and the posterior fixation were compared.ResultsCompared to the TT-TT group, the MCBT-TT showed a significant lower ROM of the L4–L5 segment (p ≤ 0.009), lower ROM of the posterior fixation (p < 0.001), lower intervertebral disc stress (p < 0.001), and lower posterior fixation stress (p ≤ 0.041). TT-MCBT groups showed a significant lower ROM of the L4–L5 segment (p ≤ 0.012), lower ROM of the posterior fixation (p < 0.001), lower intervertebral disc stress (p < 0.001), and lower posterior fixation stress (p ≤ 0.038).ConclusionsThe biomechanical properties of the hybrid MCBT-TT and TT-MCBT techniques at the L4–L5 segment are superior to that of stability MCBT-MCBT and TT-TT techniques, and feasibility needs further cadaveric study to verify

Association between hearing aid use and all-cause and cause-specific dementia: an analysis of the UK Biobank cohort.

BACKGROUND: Dementia and hearing loss are both highly prevalent conditions among older adults. We aimed to examine the association between hearing aid use and risk of all-cause and cause-specific dementia among middle-aged and older-aged adults, and to explore the roles of mediators and moderators in their association. METHODS: We used data from the UK Biobank, a population-based cohort study, which recruited adults aged 40-69 years between 2006 and 2010 across 22 centres in England, Scotland, and Wales. We used Cox proportional hazards models to estimate hazard ratios (HRs) and 95% CIs between self-reported hearing aid use status (hearing loss with or without hearing aids) at baseline and risk of dementia (all-cause dementia, Alzheimer's disease, vascular dementia, and non-Alzheimer's disease non-vascular dementia). Dementia diagnoses were ascertained using hospital records and death-register data. We also analysed the roles of mediators (self-reported social isolation, loneliness, and mood) and moderators (self-reported education and income, smoking, morbidity, and measured APOE allele status). FINDINGS: After the exclusion of people who did not answer the question on hearing difficulties (n=25 081 [5·0%]) and those with dementia at baseline visit (n=283 [0·1%]), we included 437 704 people in the analyses. Compared with participants without hearing loss, people with hearing loss without hearing aids had an increased risk of all-cause dementia (HR 1·42 [95% CI 1·29-1·56]); we found no increased risk in people with hearing loss with hearing aids (1·04 [0·98-1·10]). The positive association of hearing aid use was observed in all-cause dementia and cause-specific dementia subtypes (Alzheimer's disease, vascular dementia, and non-Alzheimer's disease non-vascular dementia). The attributable risk proportion of dementia for hearing loss was estimated to be 29·6%. Of the total association between hearing aid use and all-cause dementia, 1·5% was mediated by reducing social isolation, 2·3% by reducing loneliness, and 7·1% by reducing depressed mood. INTERPRETATION: In people with hearing loss, hearing aid use is associated with a risk of dementia of a similar level to that of people without hearing loss. With the postulation that up to 8% of dementia cases could be prevented with proper hearing loss management, our findings highlight the urgent need to take measures to address hearing loss to improve cognitive decline. FUNDING: National Natural Science Foundation of China and Shandong Province, Taishan Scholars Project, China Medical Board, and China Postdoctoral Science Foundation

Tacky Elastomers to Enable Tear-Resistant and Autonomous Self-Healing Semiconductor Composites

Mechanical failure of π-conjugated polymer thin films is unavoidable under cyclic loading conditions, due to intrinsic defects and poor resistance to crack propagation. Here, the first tear-resistant and room-temperature self-healable semiconducting composite is presented, consisting of conjugated polymers and butyl rubber elastomers. This new composite displays both a record-low elastic modulus

Tacky Elastomers to Enable Tear-Resistant and Autonomous Self-Healing Semiconductor Composites

Mechanical failure of π-conjugated polymer thin films is unavoidable under cyclic loading conditions, due to intrinsic defects and poor resistance to crack propagation. Here, the first tear-resistant and room-temperature self-healable semiconducting composite is presented, consisting of conjugated polymers and butyl rubber elastomers. This new composite displays both a record-low elastic modulus

A new equilibrium form of zircon crystal

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Comparative Study on the Kinetics of the Isothermal Reduction of Iron Ore Composite Pellets Using Coke, Charcoal, and Biomass as Reducing Agents

The kinetics of the isothermal reduction of iron ore–coke, iron ore–charcoal, and iron ore–biomass (straw) composite pellets were studied at 900–1200 °C. Compared with the other two composite pellets, the composite pellet using biomass as a reducing agent showed a more rapid reduction rate at a relatively low temperature. With an increase in the temperature, the reduction rates of the three different composite pellets tended to be equal. The reducing reactions of the three different composite pellets were all mainly controlled by gasification diffusion. The reduction rates can be described by the interface reaction kinetic model ([1−(1−m)1/3]2=kt). The apparent activation energies of the gasification diffusion of coke, charcoal, and biomass composite pellets at 900–1200 °C were calculated using the Arrhenius equation, and they were 95.81, 71.67, and 58.69 kJ/mol, respectively. The biomass composite pellets exhibited a lower apparent activation energy than the composite pellets with other reduction agents

Material for "Substrate temperature controls molecular orientation in two-component vapor- deposited glasses." Soft Matter, 2016, 12, 3265.

Data set for work presented in Jiang, J.; Walters, D. M.; Zhou, D.; Ediger, M. D. “Substrate Temperature Controls Molecular Orientation in Two -Component Vapor-deposited Glasses.” Soft Matt. 2016, 12, 3265

Extending Cooling Rate Performance of Fast Scanning Chip Calorimetry by Liquid Droplet Cooling

The liquid droplet cooling technique for fast scanning chip calorimetry (FSC) is introduced, increasing the cooling rate for large samples on a given sensor. Reaching higher cooling rates and using a gas as the cooling medium, the common standard for ultra-fast temperature control in cooling requires reducing the lateral dimensions of the sample and sensor. The maximum cooling rate is limited by the heat capacity of the sample and the heat exchange between the gas and the sample. The enhanced cooling performance of the new liquid droplet cooling technique is demonstrated for both metals and polymers, on examples of solidification of large samples of indium, high-density polyethylene (HDPE) and poly (butylene 2,6-naphthalate) (PBN). It was found that the maximum cooling rate can be increased up to 5 MK/s in room temperature environment, that is, by two orders of magnitude, compared to standard gas cooling. Furthermore, modifying the droplet size and using coolants at different temperatures provide options to adjust the cooling rate in the temperature ranges of interest