Novel unidirectional porous hydroxyapatite used as a bone substitute for open wedge high tibial osteotomy

Purpose: The purpose of this study was to clinically and radiologically evaluate the availability, osteoconductivity, and resorption of a novel unidirectional porous hydroxyapatite (UDPHAp) used as an artificial substitute for open wedge high tibial osteotomy (OWHTO). Our hypothesis was that UDPHAp is a safe and useful bone substitute for OWHTO. Materials and methods: Seven patients (2 men and 5 women aged 34-72years) who underwent OWHTO and were followed up for more than 12months were retrospectively studied. After the osteotomy, the gap created was filled with UDPHAp(REGENOS® Kuraray Co.Ltd). Radiography and computed tomography(CT) were performed, and gap healing was assessed postoperatively. The Japanese Orthopaedic Association (JOA) knee score was determined pre- and post-operatively for clinical evaluation. Results: Neither gross displacement nor collapse of the UDPHAp block graft was observed within 12 months after surgery. Both radiographs and CT showed attenuation of lucency and increasing sclerosis over time. JOA score improved from 71.2 (65?80) to 95.8 (85?100). Conclusions: Short term results for OWHTO using UDPHAp was satisfactory. Clinical improvement of JOA scores were seen, besides osteogenesis was progressing in and around the artificial bone grafts.     

Microbial-ecological significance of sulfide precipitation within anaerobic granular sludge revealed by micro-electrodes study

Micro-electrodes were applied to anaerobic granular sludge, which was developed in a UASB reactor, to examine intra-granule profiles with respect to pH, glucose and sulfide. When glucose was employed as a bulk liquid substrate, the micro-electrodes study demonstrated the pH behavior along granule depth: pH decrement at the granule exterior portion due to acid formation (buildup of acidity), and subsequent pH increment at the granule inner portion due to the consumption of acid (buildup of alkalinity). Sulfide micro-electrode proved sulfate reduction that mostly occurred at the granule exterior portion. Chemical equilibrium consideration evidently explained the occurrence of ferric sulfide predominantly in the interior portion, which accounts well for the morphology of a representative double-layered structure of granules grown on a low level of sulfite. Inorganic elements distribution within anaerobic granule was examined by electron probe X-ray micro analysis (EPMA) and ICP methods. The presence of crystalline calcium carbonate (calcite) was identified by X-ray diffraction analysis.     

The structural color in the polymer blend of poly(methyl methacrylate) and polystyrene

Morphologic and optical studies were performed on the coloring of poly(methyl methacrylate) (PMMA) and polystyrene (PS) opal sheet. It was concluded that the origin of color is the polymer structure itself. There exist three structures in the colored polymer blend: small PS spheres are dispersed in the PMMA matrix, and each PS sphere contains smaller PMMA spheres within it. The dimension of the smaller PMMA spheres is of the same order as the wavelength of visible or near-infrared light. The coloring measured by a spectrometer is well interpreted by the equation of structural color derived by Clewell qualitatively.     

A three-valued D-flip-flop and shift register using multiple-junction surface tunnel transistors

A three-valued D-flip-flop (D-FF) circuit and a two-stage shift register built from InGaAs-based multiple-junction surface tunnel transistors (MJSTT) and Si-based metal-oxide-semiconductor field effect transistors (MOSFET) have been demonstrated. Due to the combination of the MJSTTs latching function and the MOSFETs switching function, the number of devices required for the D-FF circuit was greatly reduced to three from the thirty required for the FET-only circuit.     

Quality control material for plasma fibrinogen test produced from purified human fibrinogen

Plasma fibrinogen measurement is a routine laboratory procedure commonly performed on automated coagulation analysers. Its determination is quantitative, not quantitative. Yet, a lack of precision has been an issue for fibrinogen measurement. A control material derived from plasma comprises many proteins, inhibitors and fatty acids, any or all of which can interfere in the fibrinogen assay. This study has attempted to develop a quality control material using purified human fibrinogen and has compared measurement precision between both purified and plasma materials. Purified fibrinogen was prepared using Cohn fraction 1 and glycine precipitation. Purified fibrinogen clottability was greater than 95%, with no main plasma proteins, lipids or fibrinogen degradation products observed. Two purified control materials were lyophilized at normal (2.30 g l(m1)) and abnormal (1.20 g l(m1)) levels of fibrinogen concentration. Precision was evaluated using a liquid-type reagent, Thrombocheck Fib(L), on automated coagulation analysers. Coefficient of variation for within-run, intraday and between-day precision of the purified materials was 0.7-3.5%. In comparison, the coefficient of variation for plasma materials ranged from 1.2 to 5.3%. These results suggest that materials prepared from purified fibrinogen can be useful to laboratory quality control by improving overall precision of fibrinogen measurement and are applicable to automated coagulation analysers.     

Telomerase activity in human bladder cancer

Telomerase can synthesize telomeric DNA repeats onto chromosome ends. Telomere length and telomerase activity have recently been implicated in the control of the proliferative capacity of normal and malignant cells. The expression of telomerase activity is concomitant with the attainment of immortality in tumor tissues and cells. Thus, enzyme activity may indicate a prevalent or even ubiquitous tumor producer. In this report, telomerase activity was analyzed in 40 human bladder cancers, 7 normal tissues, and 2 bladder epithelia with dysplasia using a PCR-based telomeric repeat amplification protocol assay. Telomerase activity was detected in almost all bladder tumors (97.5%); only one sample, which was in an early stage, did not express telomerase activity. None of the normal tissues displayed telomerase activity. One of the two bladder epithelia with dysplasia expressed low telomerase activity. The expression of telomerase activity has a clear association with the pathological grade and clinical stage. Most of the tumors with high telomerase activity were in an advanced grade and had deep invasion. Thus, telomerase activity might be suggested to represent an additional required event in the multigenetic process of tumorigenesis in human bladder cancer.     

Shell model calculation of enthalpy of solution of MgO in UO2+x

A computer program to evaluate the formation energies of defects in fluorite crystals is developed on the basis of the shell model Intrinsic defects of UO₂ are calculated with this program using the potential parameters reported by Catlow. The results are in agreement with those of Catlow. The present computer program is applied to a study of nonstoichiometry of the solid solutions of MgO and UO_2+x The calculation of the enthalpy of solution of MgO in UO_2+xis carried out on the basis of several defect models for charge compensation in the solid solution Mg_yU_1?yO_2±xThe calculated results are discussed in the light of our recent experimental work. It is proved that the present theoretical calculation predicts reasonably well the nonstoichiometric properties of the solid solution.