Synthesis and physical properties of (Pb0.5M0.5)(Sr,La)2CuOz (z~5; M = Fe, Co, Cu, and Zn)

(Pb0.5Cu0.5)(Sr0.5La0.5)2CuOz (abbreviated as (Pb,Cu)-"1-2-0-1") with superconducting transition temperature (Tc) of 25 K is a member (n = 1) of one of the homologous series of cuprate superconductors, (Pb4+,Cu2+)(Sr2+,Ln3+)2(Y3+,Ca2+)n-1Cu2+nO2-2n+3 (n = 1-4; Ln: lanthanoid elements). For the (Pb,Cu)-"1-2-0-1", substitution effects of 3d transition metal elements M (M = Fe, Co, and Zn) for the Cu site in the (Pb,Cu)-O charge-reservoir layer (labelled as Cu(1)) are systematically investigated. Because Fe, Co and Ni ions exist as divalent or trivalent in ionic crystals, the Sr2+/La3+ ratio in the (Sr,Ln) site is adjusted to satisfy charge neutrality, assuming that they are in a trivalent state. This results in the successful synthesis of new materials with nominal compositions of (Pb0.5M0.5)(Sr0.75La0.25)2CuOz (M = Fe and Co). This observation suggests that Fe and Co are trivalent in "1-2-0-1". For M = Zn, the nominal composition of (Pb0.5Zn0.5)(Sr0.5La0.5)2CuOz was found to yield a nearly single "1-2-0-1" phase. Temperature dependence of electrical resistivity and magnetization were measured, and superconductivity was confirmed only for the case of M = Zn with a Tc of 19.7 K. For these three materials, the distribution of Fe, Co and Zn between Cu(1) and another Cu site in the Cu-O2 plane labelled as Cu(2) was investigated employing transmission electron microscopy, which showed that Fe, Co, and Zn occupy both the Cu(1) and Cu(2) sites.Comment: 26 pages, 10 figure

Modelling the visual response to an OUReP retinal prosthesis with photoelectric dye coupled to polyethylene film

Objective. Retinal prostheses have been developed to restore vision in blind patients suffering from diseases like retinitis pigmentosa. Approach. A new type of retinal prosthesis called the Okayama University-type retinal prosthesis (OUReP) was developed by chemically coupling photoelectric dyes to a polyethylene film surface. The prosthesis works by passively generating an electric potential when stimulated by light. However, the neurophysiological mechanism of how OUReP stimulates the degenerated retina is unknown. Main results. Here, we explore how the OUReP affects retinal tissues using a finite element model to solve for the potential inside the tissue and an active Hodgkin-Huxley model based on rat vision to predict the corresponding retinal bipolar response. Significance. We show that the OUReP is likely capable of eliciting responses in retinal bipolar cells necessary to generate vision under most ambient conditions

Efficacy of radial styloid targeting screws in volar plate fixation of intra-articular distal radial fractures: a biomechanical study in a cadaver fracture model

<p>Abstract</p> <p>Background</p> <p>The locking screws target the radial styloid, theoretically provide greater stability against radial styloid fragment. However, it is unknown whether the radial styloid locking screws increased the stability of the volar plating system fixation along the entire distal radius or not. In this study, we evaluated the stability of the volar plating system fixation with or without the radial styloid screws using a biomechanical study in a cadaver fracture model.</p> <p>Methods</p> <p>Six matched pairs of fresh-frozen human cadaver wrists complete from the proximal forearm to the metacarpal bones were prepared to simulate standardized 3-part intra-articular and severe comminuted fractures. Specimens were fixed using the volar plating system with or without 2 radial styloid screws. Each specimen was loaded at a constant rate of 20 mm/min to failure. Load data was recorded and, ultimate strength and change in gap between distal and proximal fragments were measured. Data for ultimate strength and screw failure after failure loading were compared between the 2 groups.</p> <p>Results</p> <p>The average ultimate strength at failure of the volar plate fixation with radial styloid screws (913.5 ± 157.1 N) was significantly higher than that without them (682.2 ± 118.6 N). After failure loading, the average change in gap between the ulnar and proximal fragment was greater than that between the radial and proximal fragment. The number of bent or broken screws in ulnar fragment was higher than that in radial fragment. The number of specimens with bent or broken screws in cases with radial styloid screws was fewer than that in the fixation without radial styloid screws group.</p> <p>Conclusion</p> <p>The ulnar fragment is more intensively stressed than the radial fragment under axial loading of distal radius at full wrist extension. The radial styloid screws were effective in stable volar plate fixation of distal radial fractures.</p

Comparisons of kinematics during stair motion in total knee arthroplasty: Single-radius versus J-curved designs

Background: Patients who undergo TKA continue to report difficulty in ascending and descending stairs. However, it is unknown how kinematic pattern TKA knees demonstrate during stair ascending and descending. The purpose of the present study was (1) to determine how kinematics TKA knees demonstrate during stair ascending and descending; (2) to investigate whether TKA kinematics during stair ambulation are different among designs of implants as well as during squatting.Methods: We analyzed twenty two knees (19 patients, all female) that implanted with single-radius PS TKA which was the Triathlon posterior stabilized knee prosthesis or the J-curved PS TKA which was the Legacy flex posterior stabilized knee prosthesis. Each patient performed stair ascending and descending at patient’s comfortable pace. We evaluated the kinematics of stair ascending and descending using 2-dimensional to 3-dimensional registration technique.Results: Anteroposterior translation was significantly less in single-radius PS TKA compared to J-curved PS TKA during stair ascending and descending. At foot strike, post-cam engagement was observed in all 11 knees implanted with single-radius PS TKA and in three of 11 knees with J-curved PS TKA during stair ascending.Conclusions: Single-radius design of the femoral component, constrained articulation and less posterior slope might lead to less anteroposterior translation of the femur during stair ascending and descending. Additionally, it is also associated with the stability that the post cam contact prevented the femur from moving anteroposterior before and after foot strike during stair ascending and escending. It should be necessary that the post cam mechanism is designed not only for inducing rollback motion, but also for controlling anteroposterior translation in mid-flexion range

Glenohumeral joint motion after subscapularis tendon repair: an analysis of cadaver shoulder models

BACKGROUND: As for the surgical treatment of the rotator cuff tears, the subscapularis tendon tears have recently received much attention for the mini-open or arthroscopic repair. The results of surgical repair for the subscapularis tendon tear are satisfactory, but the range of external rotation is reported to be restricted after the repair. The purpose of this study was to evaluate the range of glenohumeral joint motion after repairs of various sizes of subscapularis tendon tears. METHODS: Using eight fresh frozen human cadaveric shoulders (mean age at death, 81.5 years), three sizes of subscapularis tendon tear (small, medium, and large) were made and then repaired. With the scapula fixed to the wooden jig, the end-range of glenohumeral motion was measured with passive movement applied through 1.0-Nm torque in the directions of scapular elevation, flexion, abduction, extension, horizontal abduction, and horizontal adduction. The passive end-ranges of external and internal rotation in various positions with rotational torque of 1.0 Nm were also measured. Differences in the ranges among the three type tears were analyzed. RESULTS: As tear size increased, range of glenohumeral motion in horizontal abduction after repair decreased gradually and was significantly decreased with the large size tear (P < 0.01). The end-range of external rotation decreased progressively with increasing tear size in every glenohumeral position. The prominent decrease in external rotation (around 40° reduction from intact shoulders) was observed in shoulders after repair of large size tear at 30° to 60° of scapular elevation and abduction. CONCLUSIONS: As the size of the subscapularis tendon tear increased, the passive ranges of horizontal abduction and external rotation of the glenohumeral joint after repair decreased significantly. In shoulders with a subscapularis tendon tear, it is necessary to consider the reduction of external rotation depending on tear size

Step-by-Step Procedure to Test Photoelectric Dye-Coupled Polyethylene Film as Retinal Prosthesis to Induce Light-Evoked Spikes in Isolated Retinal Dystrophic Tissue of rd1 Mice

Purpose: Multielectrode array recording for electric activity in cardiac and neuronal cells has been developed as preclinical tests for drug screening. This study aims to establish an in vitro assay system, using the multielectrode array, to record light-evoked spikes in isolated degenerative retinal tissues of retinal dystrophic rd1 mouse, as a preclinical test to examine the efficacy of photoelectric dye-coupled thin film retinal prosthesis. Methods: Light-evoked spike response was tested for 1 min at first step in the isolated degenerative retinal tissue of retinal dystrophic rd1 mouse only on the multielectrode array, tested in the same retinal tissue overlain with a plain control film for light-off and light-on 10 min each at second step, and tested in the same tissue overlain with a dye-coupled film at third step. The retinal tissues which showed light-evoked response at first or second step were not used for evaluation at third step. Results: Residual light-evoked spikes were recorded at first or second step in 18 of 35 retinal tissues (51%) at 6 weeks of the age in rd1 mice, 16 of 44 tissues (36%) at 7 weeks, and 10 of 39 tissues (25%) at 8 weeks. At third step, light-evoked spikes were recorded with dye-coupled films in 8 of 17 retinal tissues (47%) at 6 weeks, 10 of 28 tissues (35%) at 7 weeks, and 8 of 29 tissues (27%) at 8 weeks. Conclusion: A step-by-step procedure with internal control was established to measure light-evoked spikes by the multielectrode array in the isolated degenerative retinal tissue to evaluate photoelectric dye-coupled thin films. This preclinical study would present one line of evidence for the efficacy of photoelectric dye-coupled thin film retinal prosthesis towards a first-in-human clinical trial

Curved-Tip Disposable Injector (OUReP Injector) to Insert Photoelectric Dye-Coupled Polyethylene Film (OUReP) as Retinal Prosthesis into Subretinal Space of Rabbit Eyes

The photoelectric dye-coupled thin polyethylene film functions as a novel type of retinal prosthesis in subretinal space of the eye. We previously reported a novel disposable injector to insert the thin film into subretinal space of the rabbit eye by vitreous surgery. The injection system composed of two separate parts, injector and loader. A circular film in 5 mm to 10 mm diameter was pulled into a transparent tube of the loader with a commercial 25-gauge forceps. The loader tube was joined with a sleeve to tube tip of the injector. The film in the loader was pushed with a plunger for the loader into the injector tube tip. The loader with the sleeve was removed from the injector tip, and the tube tip with the film was filled with solution. This study reported a small-bore curved-tip disposable injector with outer diameter of 1.6 mm. A curved-tip polypropylene tube was formed by the process of heating and cooling of the tube inserted with a curved guide wire. The plunger for the curved-tip tube was made of a polyphenylsulfone tip connected with a press-fitting inner polypropylene tube to a nylon rod. Bleb retinal detachment in 4 surgically aphakic eyes of rabbits were induced by infusing solution into subretinal space with a 38-gauge polyimide tip, and a retinal tear was made at the edge of retinal detachment with 25-gauge diathermy. The injector tip with the rolled film in 6 mm diameter was inserted from 2 mm wide scleral incision into vitreous and then into subretinal space. The rolled films were released into subretinal space with the tip end inserted into the retinal tear, and the released films were confirmed to stay under the retina with no additional aid. Dissection one month after surgeries confirmed successful implantation of 4 films into subretinal space of each rabbit eye. The curved-tip injector could release the rolled film into the subretinal space without additional effort, compared with the straight-tip injector, and would help surgeons implant photoelectric dye-coupled thin film retinal prosthesis easily at vitreous surgery

HLA-A*0201-restricted CTL epitope of a novel osteosarcoma antigen, papillomavirus binding factor

<p>Abstract</p> <p>Background</p> <p>To develop peptide-based immunotherapy for osteosarcoma, we previously identified papillomavirus binding factor (PBF) as a CTL-defined osteosarcoma antigen in the context of HLA-B55. However, clinical application of PBF-based immunotherapy requires identification of naturally presented CTL epitopes in osteosarcoma cells in the context of more common HLA molecules such as HLA-A2.</p> <p>Methods</p> <p>Ten peptides with the HLA-A*0201 binding motif were synthesized from the amino acid sequence of PBF according to the BIMAS score and screened with an HLA class I stabilization assay. The frequency of CTLs recognizing the selected PBF-derived peptide was determined in peripheral blood of five HLA-A*0201⁺patients with osteosarcoma using limiting dilution (LD)/mixed lymphocyte peptide culture (MLPC) followed by tetramer-based frequency analysis. Attempts were made to establish PBF-specific CTL clones from the tetramer-positive CTL pool by a combination of limiting dilution and single-cell sorting. The cytotoxicity of CTLs was assessed by ⁵¹Cr release assay.</p> <p>Results</p> <p>Peptide PBF A2.2 showed the highest affinity to HLA-A*0201. CD8+ T cells reacting with the PBF A2.2 peptide were detected in three of five patients at frequencies from 2 × 10^-7to 5 × 10^-6. A tetramer-positive PBF A2.2-specific CTL line, 5A9, specifically lysed allogeneic osteosarcoma cell lines that expressed both PBF and either HLA-A*0201 or HLA-A*0206, autologous tumor cells, and T2 pulsed with PBF A2.2. Five of 12 tetramer-positive CTL clones also lysed allogeneic osteosarcoma cell lines expressing both PBF and either HLA-A*0201 or HLA-A*0206 and T2 pulsed with PBF A2.2.</p> <p>Conclusion</p> <p>These findings indicate that PBF A2.2 serves as a CTL epitope on osteosarcoma cells in the context of HLA-A*0201, and potentially, HLA-A*0206. This extends the availability of PBF-derived therapeutic peptide vaccines for patients with osteosarcoma.</p

Enhancement of Dormant Pathways in the Brain following Rat Contusive Spinal Cord Injury

Spinal cord injury (SCI) induces distal effects on neural activity in the brain. To date, precise, high quality anatomical studies have not been performed. The goal of this study was to delineate neuroanatomical enhancement of dormant pathways in the brain following SCI using an appropriate serotype of an adeno-associated-virus (AAV) with a CAG promotor