Biomechanical Study Using the Finite Element Method of Internal Fixation in Pauwels Type III Vertical Femoral Neck Fractures

Background: Several factors are known to influence osseous union of femoral neck fractures. Numerous clinical studies have reported different results, hence with different recommendations regarding treatment of Pauwels III fractures: femoral neck fractures with a more vertically oriented fracture line. The current study aimed to analyze biomechanically whether this fracture poses a higher risk of nonunion. Objectives: To analyze the influence of one designated factor, authors believe that a computerized fracture model, using a finite element Finite Element Method (FEM), may be essential to negate the influence of other factors. The current study aimed to investigate a single factor, i.e. orientation of the fracture line toward a horizontal line, represented by Pauwels classification. It was hypothesized that a model with a vertically oriented fracture line maintaining parity of all other related factors has a higher stress at the fracture site, which would delay fracture healing. This result can be applicable to other types of pinning. Patients and Methods: The finite element models were constructed from computed tomography data of the femur. Three fracture models, treated with pinning, were constructed based on Pauwels classification: Type I, 30° between the fracture line and a horizontal line; Type II, 50°; and Type III, 70°. All other factors were matched between the models. The Von Mises stress and principal stress distribution were examined along with the fracture line in each model. Results: The peak Von Mises stresses at the medial femoral neck of the fracture site were 35, 50 and 130 MPa in Pauwels type I, II, and III fractures, respectively. Additionally, the peak Von Mises stresses along with the fracture site at the lateral femoral neck were 140, 16, and 8 MPa in Pauwels type I, II, and III fractures, respectively. The principal stress on the medial femoral neck in Pauwels type III fracture was identified as a traction stress, whereas the principal stress on the lateral femoral neck in Pauwels type I fracture was a compression stress. Conclusions: The most relevant finding was that hook pinning in Pauwels type III fracture may result in delayed union or nonunion due to significantly increased stress of a traction force at the fracture site that works to displace the fracture. However, in a Pauwels type I fracture, increased compression stress contributes to stabilize it. Surgeons are recommended not to treat Pauwels type III femoral neck fractures by pinning

Traceability for areal surface texture measurement

Abstract The deterministic structuring of a surface is having a profound effect on many industrial products by allowing the manufacturer to significantly alter the way in which a surface functions. This has led to a clear need in industry and academia for traceable areal surface texture measurements. To address this need traceable transfer artefacts and primary instrumentation are required. The National Physical Laboratory (NPL) is working on two projects -one to develop areal transfer artefacts and one to develop a traceable areal surface texture measuring instrument. The authors describe the development of the artefacts and instrument, and present some of the challenges that are still required to be able to offer an areal traceability measurement service to industry. The instrument has a working volume of 8 mm x 8 mm x 0.1 mm and uses a co-planar air-bearing slideway to move the sample. It also uses a novel vertical displacement measuring probe, incorporating an air-bearing and an electromagnetic force control mechanism. The motions of the slideway and the probe are measured by laser interferometers thus ensuring traceability of the measurements to the definition of the metre. The artefacts were manufactured using a range of machining technologies and in a range of geometries suitable for stylus and optical based instruments

Universality of electron accumulation at wurtzite c- and a-plane and zinc-blende InN surfaces

Electron accumulation is found to occur at the surface of wurtzite (112¯0), (0001), and (0001¯) and zinc-blende (001) InN using x-ray photoemission spectroscopy. The accumulation is shown to be a universal feature of InN surfaces. This is due to the low Г-point conduction band minimum lying significantly below the charge neutrality level

On multigraded generalizations of Kirillov-Reshetikhin modules

We study the category of Z^l-graded modules with finite-dimensional graded pieces for certain Z+^l-graded Lie algebras. We also consider certain Serre subcategories with finitely many isomorphism classes of simple objects. We construct projective resolutions for the simple modules in these categories and compute the Ext groups between simple modules. We show that the projective covers of the simple modules in these Serre subcategories can be regarded as multigraded generalizations of Kirillov-Reshetikhin modules and give a recursive formula for computing their graded characters

Genetic Spectrum of EYS-associated Retinal Disease in a Large Japanese Cohort: Identification of Disease-associated Variants with Relatively High Allele Frequency

Biallelic variants in the EYS gene are a major cause of autosomal recessive inherited retinal disease (IRD), with a high prevalence in the Asian population. The purpose of this study was to identify pathogenic EYS variants, to determine the clinical/genetic spectrum of EYS-associated retinal disease (EYS-RD), and to discover disease-associated variants with relatively high allele frequency (1%-10%) in a nationwide Japanese cohort. Sixty-six affected subjects from 61 families with biallelic or multiple pathogenic/disease-associated EYS variants were ascertained by whole-exome sequencing. Three phenotype groups were identified in EYS-RD: retinitis pigmentosa (RP; 85.94%), cone-rod dystrophy (CORD; 10.94%), and Leber congenital amaurosis (LCA; 3.12%). Twenty-six pathogenic/disease-associated EYS variants were identified, including seven novel variants. The two most prevalent variants, p.(Gly843Glu) and p.(Thr2465Ser) were found in 26 and twelve families (42.6%, 19.7%), respectively, for which the allele frequency (AF) in the Japanese population was 2.2% and 3.0%, respectively. These results expand the phenotypic and genotypic spectrum of EYS-RD, accounting for a high proportion of EYS-RD both in autosomal recessive RP (23.4%) and autosomal recessive CORD (9.9%) in the Japanese population. The presence of EYS variants with relatively high AF highlights the importance of considering the pathogenicity of non-rare variants in relatively prevalent Mendelian disorders

Polypyrrole-Fe2O3 nanohybrid materials for electrochemical storage

We report on the synthesis and electrochemical characterization of nanohybrid polypyrrole (PPy) (PPy/Fe2O3) materials for electrochemical storage applications. We have shown that the incorporation of nanoparticles inside the PPy notably increases the charge storage capability in comparison to the “pure” conducting polymer. Incorporation of large anions, i.e., paratoluenesulfonate, allows a further improvement in the capacity. These charge storage modifications have been attributed to the morphology of the composite in which the particle sizes and the specific surface area are modified with the incorporation of nanoparticles. High capacity and stability have been obtained in PC/NEt4BF4 (at 20 mV/s), i.e., 47 mAh/g, with only a 3% charge loss after one thousand cyles. The kinetics of charge–discharge is also improved by the hybrid nanocomposite morphology modifications, which increase the rate of insertion–expulsion of counter anions in the bulk of the film. A room temperature ionic liquid such as imidazolium trifluoromethanesulfonimide seems to be a promising electrolyte because it further increases the capacity up to 53 mAh/g with a high stability during charge–discharge processes

Near Infrared Imaging Survey of Bok Globules: Density Structure

On the basis of near-infrared imaging observations, we derived visual extinction (Av) distribution toward ten Bok globules through measurements of both the color excess (E_{H-K}) and the stellar density at J, H, and Ks (star count). Radial column density profiles for each globule were analyzed with the Bonnor-Ebert sphere model. Using the data of our ten globules and four globules in the literature, we investigated the stability of globules on the basis of xi_max, which characterizes the Bonnor-Ebert sphere as well as the stability of the equilibrium state against the gravitational collapse. We found that more than half of starless globules are located near the critical state (xi_max = 6.5 +/- 2). Thus, we suggest that a nearly critical Bonnor-Ebert sphere characterizes the typical density structure of starless globules. Remaining starless globules show clearly unstable states (xi_max > 10). Since unstable equilibrium states are not long maintained, we expect that these globules are on the way to gravitational collapse or that they are stabilized by non-thermal support. It was also found that all the star-forming globules show unstable solutions of xi_max >10, which is consistent with the fact that they have started gravitational collapse. We investigated the evolution of a collapsing gas sphere whose initial condition is a nearly critical Bonnor-Ebert sphere. We found that the column density profiles of the collapsing sphere mimic those of the static Bonnor-Ebert spheres in unstable equilibrium. The collapsing gas sphere resembles marginally unstable Bonnor-Ebert spheres for a long time. We found that the frequency distribution of xi_max for the observed starless globules is consistent with that from model calculations of the collapsing sphere.Comment: Accepted for publication in the Astronomical Journal. 39 pages in preprint format, including 10 figures. The version with higher resolution figures can be obtained at the following site (http://alma.mtk.nao.ac.jp/~kandori/preprint/

Two-Dimensional Vanadium Carbide (MXene) as Positive Electrode for Sodium-Ion Capacitors

Ion capacitors store energy through intercalation of cations into an electrode at a faster rate than in batteries and within a larger potential window. These devices reach a higher energy density compared to electrochemical double layer capacitor. Li-ion capacitors are already produced commercially, but the development of Na-ion capacitors is hindered by lack of materials that would allow fast intercalation of Na-ions. Here we investigated the electrochemical behavior of 2D vanadium carbide, V2C, from the MXene family. We investigated the mechanism of Na intercalation by XRD and achieved capacitance of ∼100 F/g at 0.2 mV/s. We assembled a full cell with hard carbon as negative electrode, a known anode material for Na ion batteries, and achieved capacity of 50 mAh/g with a maximum cell voltage of 3.5 V

Inhibition of Apoptosis Blocks Human Motor Neuron Cell Death in a Stem Cell Model of Spinal Muscular Atrophy

Spinal muscular atrophy (SMA) is a genetic disorder caused by a deletion of the survival motor neuron 1 gene leading to motor neuron loss, muscle atrophy, paralysis, and death. We show here that induced pluripotent stem cell (iPSC) lines generated from two Type I SMA subjects–one produced with lentiviral constructs and the second using a virus-free plasmid–based approach–recapitulate the disease phenotype and generate significantly fewer motor neurons at later developmental time periods in culture compared to two separate control subject iPSC lines. During motor neuron development, both SMA lines showed an increase in Fas ligand-mediated apoptosis and increased caspase-8 and-3 activation. Importantly, this could be mitigated by addition of either a Fas blocking antibody or a caspase-3 inhibitor. Together, these data further validate this human stem cell model of SMA, suggesting that specific inhibitors of apoptotic pathways may be beneficial for patients