Capillary rise properties of porous mullite ceramics prepared by an extrusion method using organic fibers as the pore former

Porous mullite ceramics with unidirectionally oriented pores were prepared by an extrusion method to investigate their capillary rise properties. Rayon fibers 16.5 μm in diameter and 800 μm long were used as the pore formers by kneading with alumina powder, kaolin clay, China earthen clay and binder with varying Fe₂O₃ contents of 0, 5 and 7 mass%. The resulting pastes were extruded into cylindrical tubes (outer diameter (OD) 30–50 mm and inner diameter (ID) 20–30 mm), dried at room temperature and fired at 1500 °C for 4 h. The bulk densities of the resulting porous ceramics ranged from 1.31 to 1.67 g/cm³, with apparent porosities of 43.2–59.3%. The pore size distributions measured by Hg porosimetry showed a sharp peak at 10.0 μm in the sample without Fe₂O₃ and at 15.6 μm in the samples containing Fe₂O₃; these pores, which arose from the burnt-out rayon fibers, corresponded to total pore volumes ranging from 0.24 to 0.34 ml/g. SEM showed a microstructure consisting of unidirectionally oriented pores in a porous mullite matrix. Prismatic mullite crystals were well developed on the surfaces of the pore walls owing to the liquid phase formed by the Fe₂O₃ component added to color the samples. The bending strengths of the tubular samples ranged from 15.6 to 26.3 MPa. The height of capillary rise, measured under controlled relative humidities (RH) of 50, 65 and 85%, was greater in the ceramics containing Fe₂O₃ than in those without Fe₂O₃, especially in the thinner samples. The maximum capillary rise reached about 1300 mm, much higher than previously reported. This excellent capillary rise ability is thought to be due to the controlled pore size, pore distribution and pore orientation in these porous mullite ceramics.     

Low temperature preparation and machinability of porous ceramics from talc and foamed glass particles

Porous ceramics were prepared by firing mixtures of talc (Mg₃Si₄O₁₀(OH)₂) and foamed glass particles (ceramic balloons, CB) with and without LiCl as a sintering acid. The mixing ratios of the starting materials were talc:CB = 7:3, 8:2, 9:1 and 10:0, with additions of LiCl of 0, 2 and 5 mass%. The mixtures were formed into pellets and fired at 600–1000 °C. The pellets without LiCl showed very poor strength even when fired at 1000 °C but those containing LiCl were much stronger, even when fired at only 600 °C. The crystalline phases in these samples changed to enstatite (MgSiO₃) at ≥ 700 °C by decomposition of the talc under the fluxing action of the LiCl. The resulting samples were machinable and easily cut and drilled. The cutting rate decreased with increasing bending strength, for example, from 105 mm²/s and 6.3 MPa to 50 mm²/s and 16.3 MPa, respectively. The drilling rate of the present sample was found to be only slightly less than Teflon (polytetrafluoroethylene, PTFE) but much faster than graphite, glass ceramics, etc.     

Structure and chemical properties of a copper(II) hydrazido complex: [{Cu(HB(3,5-iPr2pz)3)}2(μ-NCOOEt)2]

The novel copper(II) hydrazido(2?) complex ligated by hydrotris(pyrazolyl)borate was synthesized to obtain insight into the copper coordination chemistry in the presence of diazene and hydrazine ligands. The structure of [{Cu(L1)}₂(μ-NCOOEt)₂] was determined by X-ray crystallography, where L1 = hydrotris(3,5-diisopropyl-1-pyrazolyl)borate anion, and along with spectroscopic characterization, e.g. UV–Vis and ESR, prove the presence of copper(II) centers.     

Chemical shift measurements of chlorine K X-ray spectra using a high-resolution PIXE system

A high-efficiency high-resolution wavelength-dispersive spectrograph with a von-Hamos configuration was developed for chemical state identification of elements in environmental samples using PIXE analysis. To evaluate the performance of this system, chlorine K X-ray spectra for NaCl, NH₄Cl and polyvinylchloride (PVC) targets were measured and compared. Also, to study the applicability to environmental mixed samples, mixtures of NaCl and NH₄Cl with different mixing ratios were measured. Through observation of Cl Kα₁ X-ray from NaCl, the energy resolution of the system was determined to be 1.1 eV. For the NaCl sample, a Kβ_x line was observed at an energy, which is higher than that of the Kβ main peak by 2 eV, whereas no Kβ_x emission was observed for the NH₄Cl sample. The chemical shift of the Kβ main peak for PVC relative to that for NaCl was about 1.2 eV. For NaCl-NH₄Cl mixture targets, the relative intensity of Kβ_x satellite to the Kβ main line provided an indication of mixing ratio. Energies and relative intensity of Cl Kβ X-ray satellites for NaCl and NH₄Cl samples calculated by a simple molecular-orbital method agreed only qualitatively with the experimental results.     

IL-6 functions in cynomolgus monkeys blocked by a humanized antibody to human IL-6 receptor

A humanized antibody to the human interleukin-6 receptor (IL-6R), hPM-1, blocked the interleukin-6 (IL-6) functions in normal cynomolgus monkey lymphocytes in vitro. The binding activity of hPM-1 to non-human primate IL-6R was examined in peripheral blood lymphocytes by flow cytometry. PM-1 recognized the IL-6R on T lymphocytes of cynomolgus and rhesus monkeys, but did not on those of marmosets. The homology between human IL-6R and its cynomolgus monkey counterpart was 97.3% in the extracellular domain of the amino acid sequence, as determined by DNA sequencing of the PCR product from peripheral blood mononuclear cells. PM-1 inhibited two functional parameters in vitro in cynomolgus monkeys: (1), T-cell proliferation stimulated by phytohemaglutinin and human IL-6; (2), Immunoglobulin G-production evoked by Staphylococcus aureus Cowan-1- and human IL-6-stimulated B lymphocytes. These data show that hPM-1 binds to and functionally blocks the cynomolgus monkey IL-6 receptors.     

Apoptosis enhanced by soluble factor produced in feline immunodeficiency virus infection

Feline immunodeficiency virus (FIV)-infected cells have been shown to undergo apoptosis by treatment with tumor necrosis factor alpha (TNF-alpha). This study detected a soluble factor which enhanced the apoptosis induced by TNF-alpha treatment. The sensitivity to TNF-alpha in the induction of apoptosis in a feline fibroblastoid cell line (CRFK) cells was significantly enhanced when the culture supernatant of FIV-infected CRFK cells or plasma samples from FIV-infected cats was added to the culture. These findings suggested that FIV infection induces production of a soluble factor which enhances CRFK cells sensitivity to TNF-alpha induction of apoptosis both in vitro and in vivo. This factor may contribute to the loss of lymphocytes in cats infected with FIV.     

Immunoglobulin-complexed aspartate aminotransferase

We reviewed our experience with 9,726 cases of fine-needle aspiration cytology of the breast that were done from January 1983 to February 1992. During our review, we found that 214 aspirates had been submitted from pregnant and lactating women for the investigation of breast mass(es). Despite a variable clinical presentation and spectrum of cytologic findings, we considered the application of aspiration cytology in these women as useful as in the nonpregnant-nonlactating women for management decision. A team approach between the clinician and cytopathologist was always maintained; with this approach, the false-positive or -negative diagnoses were reduced to almost nil. In all cases in which the cytodiagnosis of carcinoma of breast was made, the findings corresponded with subsequent cell blocks from the aspirate and tissue examination. Benign lesions were diagnosed cytologically with minimal difficulty, and all aspirates that were less than optimal for cytodiagnosis were repeated to minimize the chance of missing an abnormality. All the benign lesions were followed throughout pregnancy, postpartum, and thereafter; if the mass persisted, the aspiration was repeated. With this protocol of follow-up, the need for a customary liberal surgical biopsy was reduced to a minimum.     

A multimode digital detector readout for solid-state medicalimaging detectors

A multipurpose digital detector readout for medical imaging applications is presented. The readout is capable of measuring both current and charge, allowing a single detector array to perform imaging functions previously accomplished with two separate machines. The circuit employs a variable rate ΣΔ analog-to-digital converter (ADC) to measure current over a 130-dB dynamic range in a 1 kHz band and resolve charge pulses down to 360 e^- at 100 000 events/s. Detector currents of up to 7 μA and charge pulses as large as 25 fC can be measured. A low-noise charge sensing amplifier (CSA) is combined with digital pulse shaping to optimize the noise performance and flexibility of the charge measurements. Fabricated in an 1.2 μm complimentary metal-oxide-semiconductor (CMOS), the circuit occupies 1.5 mm² and dissipates 11 mW/channel from a 5 V supply     

Morphological and functional factors predicting bladder deterioration after spinal cord injury

PURPOSE: We investigated factors predictive of morphological and functional deterioration of the bladder in patients with spinal cord injury. MATERIALS AND METHODS: Urological evaluation, including excretory urography and urodynamic studies, was performed once a year in 66 patients. Bladder compliance was used as an index of bladder function. RESULTS: Mean age of the patients with worsening bladder form and function was significantly greater than that of those with no change. In patients with worsening bladder function intermittent catheterization was performed less frequently and mean catheterization volume was greater compared to those with improvement and no change. Catheterization was less frequent and at long intervals in patients with a high urethral closure pressure. CONCLUSIONS: High storage pressure due to a high urethral closure pressure is believed to cause deterioration of bladder form and function.