Effect of Nb and Sc doping on the phase transformation of sol-gel processed TiO2 nanoparticles

Nb and Sc doped TiO2 nanoparticles were synthesized via sol-gel technique. Dopant concentration of each element was varied from 0.5 to 1.5 atomic%. The effect of metal ion doping and calcination temperatures on anatase to rutile phase transformation has been investigated. Samples were analyzed by various analytical methods such as X-ray diffraction (XRD), Transmission Electron Microscope (TEM), X-ray Photoelectron Spectroscopy (XPS) and Energy Dispersive X-ray Spectroscopy (EDS). XRD analyses showed that Nb and Sc doped samples calcined at 300 degrees C and 350 degrees C, respectively, were crystalline and had an anatase structure. Results showed that anatase was stable up to 700 degrees C annealing temperature for samples doped with 0.5 atomic% Nb. There was a sharp transition from anatase to rutile phase above 700 degrees C and complete rutile structure was obtained at 750 degrees C. However, the transformation from anatase to rutile was not so sharp in samples doped with 1.0 atomic% and 1.5 atomic% Nb. Results indicated that higher concentration of Nb helps to stabilize the anatase phase. For samples doped with 0.5 atomic% Sc, anatase phase is stable up to 650 degrees C. Transformation from anatase to rutile starts at temperature above 650 degrees C and 100% rutile phase was obtained at 800 degrees C while for samples doped with 1.0 atomic% and 1.5 atomic% Sc, the complete transformation from anatase to rutile takes place at an even higher temperature. Results indicate that increasing the calcination time from 0.5 to 2.0 hours at 500 degrees C does not affect the stability of anatase phase. However, TEM and XRD data showed that the increase in the annealing time leads to an increase in particles size. The rutile to anatase concentration ratio increased with temperature above the phase transformation temperature. The activation energy for the phase transformation from anatase to rutile for doped and undoped samples was also measured. There was a general rise in the activation energy with increasing dopant concentration.

Mechanical shear wave induced by piezoelectric ceramics for magnetic resonance elastography

Magnetic resonance elastography (MRE) is a noninvasive technique to measure elasticity of tissues in vivo. For MRE, an additional actuator is needed to be mounted on an observed object, and to excite the object. In this paper, an experiment is set to obtain MR mechanical shear wave images. A novel actuator is proposed to generate mechanical wave propagating inside a gel phantom. The actuator is made of piezoelectric ceramics, and is fixed on a plexiglass bracket. Both of the gel phantom and the actuator are put into a head coil in the scanner's bore. The actuator works synchronously with an imaging sequence running on the scanner. The sequence is modified from a FLASH sequence, into a motion-sensitizing phase-contrast sequence, for shear wave imaging. Wave images are presented to show the effect of those factors, such as the stiffness of the phantoms, the frequency of the actuator, the parameters of the motion-sensitizing gradient, and the oscillation of the patient bed.

Comparative study of barnidipine and felodipine in Chinese patients with essential hypertension

This study evaluated the efficacy and safety of barnidipine for the treatment of mild-to-moderate essential hypertension in Chinese patients. A total of 131 patients were randomized to receive either barnidipine (10 -15 mg) or felodipine (5 - 10 mg) once daily for 4 weeks. Both drugs reduced blood pressure significantly, with > or = 87% of patients obtaining a marked or moderate effect. The mean +/- SD reductions in systolic and diastolic blood pressure were 19.2 +/- 13.6 and 14.4 +/- 7.0 mmHg, respectively, for barnidipine treatment, and 20.3 +/- 11.3 and 14.7 +/- 7.7 mmHg, respectively, for felodipine treatment. There were no significant differences between the two drugs in terms of anti-hypertensive effect, heart rate, laboratory test results or incidence of adverse events. More patients taking felodipine experienced palpitations, but this difference was not statistically significant. Barnidipine is as efficacious and safe as felodipine in the treatment of essential hypertension in Chinese patients.

Study of Nd3+, Pd2+, Pt4+, and Fe3+ dopant effect on photoreactivity of TiO2 nanoparticles

The metallorganic chemical vapor deposition method was successfully used to synthesize pure TiO(2) and Nd(3+)-, Pd(2+)-, Pt(4+)-, and Fe(3+)-doped TiO(2) nanoparticles. Polycrystalline TiO(2) structure was verified with x-ray diffraction, which showed typical characteristic anatase reflections without any separate dopant-related peaks. Transmission electron microscopy observations confirmed the existence of homogeneously distributed 22 +/- 3 nm TiO(2) nanoparticles. The particle size remained the same for the doped samples. The doping level of transition metals was kept at approximately 1 atomic percent, which was determined by x-ray photoelectron spectra and energy dispersive x-ray spectroscopy. The effects of different types of dopants on the photocatalytic activity were revealed by the degradation of 2-chlorophenols with an UV light source. The photocatalytic efficiency was remarkably enhanced by the introduction of Pd(2+) and Nd(3+). Nd(3+)-doped TiO(2) showed the largest enhancement. However, Pt(4+) changed the 2-chlorophenol degradation rate only slightly, and Fe(3+) was detrimental to this process. These effects were related to the position of the dopants in the nanoparticles and the difference in their ionic radii with respect to that of Ti(4+).

[Construction of membrane-anchored interleukin-6 receptor beta subunit mutant and its effect on IL-6 signal transduction]

OBJECTIVE

To investigate whether the membrane-anchored gp130 mutant containing the second and the third fibronectin type III modules of the extracellular region could still transduce IL-6 signal.

METHOD

The membrane-anchored gp130 mutant cDNA was amplified by the overlap extension PCR and inserted into the mammalian expression vector pRc/RSV. The mutant was proved to be effectively expressed in SKO-007 cells and Jurkat cells by dot blot hybridization. The mutant's effects on IL-6 signaling in these two kinds of cells were detected by electrophoresis mobility shift assay (EMSA).

RESULTS

In SKO-007 cells, the mutant could enhance the activated APRF, but the effect was not as strong as that of wide-type gp130. IL-6 could not activate nuclear factors in Jurkat cells. After the expression vectors pRc/RSVgp130 and pRc/RSV were transfected into Jurkat cells, IL-6 could activate APRF, but could not do NF-IL6. Similar to the results in SKO-007 cells, the effects of the mutant was also weaker than that of wild-type gp130.

CONCLUSION

Although the mutant could still transduce IL-6 signal, it is not as efficiently as the wild-type gp130. It suggested that the Ig-like domain of gp130 also played an important role in IL-6 signal transduction.

[The expression of CD15 mRNA CD44v6 mRNA and nm23H1 mRNA in breast cancer and their clinical significance]

OBJECTIVE

To study the relationship of the expression of CD15 mRNA and its protein, CD44v6 mRNA and nm23H1 mRNA with the clinical pathology parameter and prognosis of breast cancer, and to investigate the correlation of the expression of CD15 mRNA with CD44v6 mRNA and nm23H1 mRNA.

METHODS

Catalyzed signal amplification (CSA) method of in situ hybridization and immunohistochemistry were used to detect the expression of CD15 mRNA and its protein, CD44v6 mRNA and nm23H1 mRNA in 94 cases of breast cancer.

RESULTS

The overexpression of CD15 mRNA and its protein and CD44v6 mRNA and the low expression nm23H1 mRNA were correlated with the grading, clinical stage, lymph node metastasis, recurrence and prognosis of breast cancer. Patients who had overexpression of CD15 mRNA and CD44v6 mRNA and low expression of nm23H1 mRNA had a higher lymph node metastatic rate and a lower survival rate.

CONCLUSION

The expression of CD15 mRNA has a synergistic action in positive and negative regulation with that of CD44v6 mRNA and nm23H1 mRNA. Combining detection of the expression of these three mRNA is a reliable index to evaluate the metastasis, recurrence and prognosis of breast cancer.

[The spectra and thermodynamics of axial coordination reaction of tailed valine tetraphenylporphintozinc with pyrimidine]

The electronic absorption spectra and thermodynamics of axial coordination reaction of 5-(4-valine butoxyphenyl)-10,15,20-tri(4-chlorophenyl)porphintozinc with pyrimidine in CHCl3 were studied. Coordination numbers and equilibrium constants of axial coordination reaction were measured by visible spectra techniques. The changes of standard molar enthalpies and standard molar entropies of reaction were obtained from the plots of ln beta vs 1/T. The influence of temperature on the axial reaction was discussed.

[Clinical and histopathological studies of melanocytoma of the optic disc]

OBJECTIVE

To examine the clinical features that may be useful in determining the malignant transformation of a melanocytoma of the optic disc.

METHODS

The clinical documentation of 10 cases, including visual acuity, visual field, fundus findings and fluorescein angiogram were analyzed retrospectively. Three of them undergone histopathologic examinations.

RESULTS

A benign melanocytoma may have some degree of decreased visual acuity, progressive nerve fiber bundle defect, certain amount of pigment dispersion into the vitreous, slight macular exudation and extension of the tumor tissue into the peripapillary area of the retina.

CONCLUSION

The progression of the associated clinical symptoms and signs appears to be not necessarily indicative of a malignant transformation of the benign disease unless they are associated with rapid enlargement of the tumor mass as well as marked pigmentary changes of the tumor surface.

A feasible and effective technique for the detection of Schistosoma japonicum cercaria-infested water

OBJECTIVE

To develop a new technique for detecting Schistosoma japonicum (S. japonicum) cercariae so as to predict the distribution of area with high transmission potential and to control acute infection of schistosoma.

METHODS

A C-6 film was established and used to adhere the cercariae on water surface and compared with a few other conventional detecting techniques.

RESULTS

The average rate of the cercaria-recovery was 40% in laboratory and field using C-6 film, which was 20 times higher than that of traditional nylon-tissue adsorbing and precipitating method. Either in some areas where oncomelania were present or in some places where the snail had been under control, the technique could detect the cercariae.

CONCLUSION

The technique can be characterized by a feasible, economical, promptly accessible method, especially for field application.

[The applied anatomy and measure of nasolacrimal duct]

OBJECTIVE

To know the anatomy of nasolacrimal duct.

METHOD

80 half-skulls of chinese adult were used to observe shapes of the orifice.

RESULT

Five shapes of the orifice were found. Slit-shape was the most in all shapes. 73 nasolacrimal ducts and situation of orifices have been measured with results as follows: (1) The nasolacrimal duct length is 14.14 mm (mean value); (2) The distance from the inferior margin of the anterior nostril to the anterior margin of the orifice (D.N.O.) is 29.00 mm (mean value); (3) The distance from the anterior attachment of the inferior turbinate to the anterior margin of the orifice is 11.70 mm (mean value); (4) The distance from the inferior margin of the anterior nostril to the anterior attachment of the inferior turbinate (D.N.T) is 18.30 mm (mean value). With analysis of linear regression, the relationship between the "D.N.T." and the nasolacrimal duct length, the "D.N.T." and the "D.N.O." is positive linear correlation respectively, "D.N.T." has been able to be measured easily, so the nasolacrimal duct length and the situation of the orifice have been recognized.

CONCLUSION

D.N.T. may be used in clinical teaching and researching work.

Voltage-dependent ion channel formation by rigid rod-shaped polyols in planar lipid bilayers

In this Letter, we describe the appearance of large, voltage-dependent currents in BLM induced by rigid rod-shaped polyols that function without charge and permanent dipole moment. The capacity of these symmetrical, nonpeptide models to form either short-living nanopores or small ion channels is shown to depend critically on the length of rigid-rod scaffold as well as the nature of the lateral side chains.

Effects of dofetilide, a class III antiarrhythmic drug, on various ventricular arrhythmias in dogs

Dofetilide, a new class III antiarrhythmic agent, was tested in various kinds of canine ventricular arrhythmias to compare its effects with those of other class III agents. Ventricular arrhythmia models used were induced by two-stage coronary ligation, digitalis, epinephrine, coronary ligation and reperfusion, and programmed electrical stimulation (PES). Dofetilide (100 micrograms/kg intravenously) did not suppress automaticity arrhythmias induced by two-stage coronary ligation and epinephrine or the coronary ligation and reperfusion arrhythmias, but suppressed the reentry arrhythmia induced by PES in dogs with old myocardial infarction (MI). This effect was associated with a prolongation of QT interval. Dofetilide also showed antiarrhythmic effect in some dogs with digitalis arrhythmia. Dofetilide increased QT interval and showed negative chronotropic effect like that of other class III drugs, but was different in antiarrhythmic profiles from those of other class III agents such as D-sotalol, E-4031, and MS-551 in that it did not prevent the occurrence of ventricular fibrillation (VF) immediately after coronary reperfusion and had some antiarrhythmic effects on digitalis arrhythmia.

Effects of the antihypoxic and neuroprotective drug, lubeluzole, on repolarization phase of canine heart assessed by monophasic action potential recording

The cardiovascular effects of the antihypoxic and neuroprotective drug, lubeluzole, were investigated using beagle dogs anesthetized with halothane. Endocardial-contact electrode catheter was used for continuous monitoring of monophasic action potential (MAP), which could provide a precise information of repolarization phase. Intravenous administration of an efficacious dose of lubeluzole (0.63 mg/kg, n = 6) slightly decreased both the heart rate and the blood pressure. It did not change PQ interval and QRS width, while it significantly prolonged QT interval, corrected QT (QTc) and the duration of the MAP during the observation period over 60 min. The effects of drug on repolarization phase were late-onset and long-lasting compared with the time course of plasma drug concentrations, which changed as predicted by the two-compartment theory of pharmacokinetics. Additional injection of lubeluzole (2.5 mg/kg, n = 6) showed qualitatively similar changes to those of lower dose, and did not induce the cardiovascular collapse in any dog. Neither afterdepolarization nor ventricular escaped beat was detected during the observation period. The drug concentration in cardiac tissue was correlated linearly with the plasma drug concentration at 60 min after the second drug administration. These results indicate that lubeluzole exerts only minor cardiovascular effects except the prolongation of the repolarization period. The monitoring of plasma drug concentration may be helpful to estimate the steady-state distribution of drug to the heart, but less helpful to predict the QT prolongation. In future clinical trials, care must be taken with patients, especially those at risk to have prolonged repolarization.

Immunohistochemical evidence of neuronal and glial differentiation in retinoblastoma

BACKGROUND

The study sought to investigate the histogenesis of retinoblastoma.

METHODS

One hundred specimens of retinoblastomas were examined along with those of 18 astrocytic gliomas and 15 medulloblastomas to compare similarities of glial differentiation in retinoblastoma and the two types of brain tumour. Employing avidin-biotin immunoperoxidase technique, antibodies were applied against neuron specific enolase (NSE), glial fibrillary acidic protein (GFAP), and S-100 protein (S-100).

RESULTS

Most rosettes and fleurettes, and some undifferentiated cells in retinoblastomas were NSE positive, but GFAP and S-100 negative. GFAP and S-100 positive cells in retinoblastomas were detected mostly in well differentiated glial cells which were interpreted as reactive or non-neoplastic cells. Some of the GFAP and S-100 positive cells in retinoblastomas were defined as tumour cells that resembled neoplastic astrocytes in astrocytic gliomas and medulloblastomas.

CONCLUSION

Retinoblastoma may arise from primitive bipotential or multipotential cells capable of neuronal and glial differentiation.

[Histopathologic classification of 1921 orbital tumors]

PURPOSE

The retrospective study is undertaken to determine the histopathologic types of space-occupying lesions of the orbit in 1921 cases examined between 1953-1992 at the Eye Pathology Laboratory of Shanghai Medical University.

METHODS

The authors reviewed old diagnostic pathologic slides on file including HE stain as well as special stains, if available, for all the indeterminate cases. Newly prepared immunohistochemical stains are made for the controversial cases to help diagnosis. Some slides are discussed and diagnosed by Pathology Slide Meeting of the Shanghai Surgical Pathology Society. Cases with diagnosis not agreed upon by the pathology meeting are excluded from this study.

RESULTS

The 5 leading malignant orbital tumors are malignant lacrimal gland tumors (138 cases, 32%), malignant lacrimal sac tumors (112 cases, 26%), rhabdomyosarcomas (65 cases, 15%), lymphosarcomas (56 cases, 13%), and malignant hemangiopericytomas (31 cases, 7%). The 5 leading benign orbital tumors are cavernous hemangionas (411 cases, 36%), dermoid cysts (152 cases, 13%), benign mixed tumors (150 cases, 13%), inflammatory pseudotumosr (129 cases, 11%), and schwannomas (92 cases, 8%). Rare tumors of the orbit include alveolar soft tissue sarcoma, chondrosarcoma, mesenchymal chondrosarcoma, synovial sarcoma, giant cell tumor, granular myoblastoma, yolk sac tumor, and retinal anlage tumor.

CONCLUSION

This study, in agreement with other reports of the statics study of the orbital tumors demonstrates the prevalence of hemangiomas, lacrimal gland tumors and lymphoid pseudo-tumors to be the common space-occupying lesions in the orbit. Some rare tumors are discussed.

[Primary epithelial lacrimal gland tumors: the pathologic classification of 272 cases]

This paper reports the pathologic classification of 272 cases with primary epithelial lacrimal gland tumors in comparison with that of the salivary glands. The extensive series of lacrimal gland tumors accounts for 70% of the 390 lacrimal fossa lesions and 18% of the 1,530 orbital tumors in one single hospital. Benign mixed tumors ranked the first (52%), adenocystic carcinomas the second (25%) and malignant mixed tumors (9%) the third. Among the other less common tumors the authors identified, for the first time, 3 polymorphous low-grade adenocarcinomas, 2 spindle celled myoepitheliomas and 1 carcinosarcoma of the lacrimal gland. The diagnosis and differential diagnosis of polymorphous low-grade adenocarcinoma and spindle cell myoepithelioma were discussed.

[An experimental study and preliminary clinical report of shape-memory sawtooth-arm embracing internal fixator]

The sawtooth-arm internal embracing fixator is made of Nickel-Titanium shape memory alloy and consists of 3 components: body, arms and sawteeth. In cross section a 2/3 circumference is constructed by body and arms of the fixator. The free ends of the arms which exceed the semi-circle are bent more medially so that it can match the requirement of fixation of long tubular bone whose cross section is not a regular circle. The embracing fixator has two types: the cylinder type is for use in the middle part and the cone type is either for the proximal or distal 1/3 of the shaft of long tubular bone. The animal experimental studies and in vitro mechanical tests demonstrated that the embracing fixator possesses good anti-bending and anti-torsion effects, and its resisting compression effect was much lower than that of bone plate. These characteristics are beneficial for enhancing fracture healing, reducing post fixation osteoporosis and providing a new, simple and effective method for the treatment of long tubular bone fracture. The fixator has already been used in the treatment of fractures of femur, humerus, radius and ulna with good results.

[Analysis of risk factors in postinfarction angina]

The clinical and echocardiographic variables related to postinfarction angina were evaluated in 54 patients with acute myocardial infarction. All patients underwent 2D echocardiography at 2-3 weeks after infarction. Wall motion analysis was quantified with a wall motion score index (WMSI) based on 16 left ventricular wall segments. Among the 54 patients with acute myocardial infarction 23 (42.6%) had early postinfarction angina. Multiple regression analysis demonstrated no significant difference between the patients with and without postinfarction angina in age, sex, location of infarction, Killip classification, previous angina, hypertension, hyperlipidemia, diabetes mellitus, creatine kinase level and left ventricular ejection fraction. In comparison with patients without postinfarction angina, patients with postinfarction angina had higher WMSI. It indicates that postinfarction angina appears to be related more to myocardial ischemia rather than to the infarct of myocardium.

Magnetic susceptibility mapping of the human thorax using a SQUID biomagnetometer

Biomagnetism is essentially the study of the weak magnetic fields generated by biological organisms, in particular the human body. The human thorax is composed of a variety of tissues and organs of slightly different magnetic susceptibility. In an applied magnetic field (of the order of milliTeslas) these small differences in susceptibility lead to measurable field variations (of the order of nanoTeslas) at the body surface which may be of diagnostic value. Physiological processes such as cardiac activity, cardiac output, blood flow and respiratory related lung volume changes also contribute to the observed signal. In this study susceptibility 'maps' were obtained by measuring the magnetic field at several hundred points over the thorax. Results indicate that magnetic susceptibility mapping produces low-resolution images of internal body structures from which is should be possible to detect pathologies that cause alterations in tissue susceptibility.

The toxic effects, GSH depletion and radiosensitivity by BSO on retinoblastoma

Retinoblastoma is the most common intraocular malignant tumor in children. Previous investigations have reported that buthionine sulfoximine (BSO) can deplete intracellular glutathione (GSH) by specific inhibition and increase cellular radiosensitivity. The toxic effects, GSH depletion and radiosensitivity of BSO on retinoblastoma cells are reported in this paper. GSH content of retinoblastoma cell lines Y-79, So-Rb50 and retinoblastoma xenograft is 2.7 +/- 1.3 x 1.0(-12) mmol/cell, 1.4 +/- 0.2 x 1.0(-12) mmol/cell, and 2.8 +/- 1.2 mumol/g, respectively. The ID50 of BSO on Y-79 and So-Rb50 in air for 3 h exposure is 2.5 mM and 0.2 mM, respectively. GSH depletion by 0.1 mM BSO for 24 h on Y-79 cells and 0.01 mM BSO for 24 h on So-Rb50 cells is 16.35%, and 4.7% of control. GSH depletion in tumor and other organ tissues in retinoblastoma-bearing nude mice after BSO administration is differential. GSH depletion after BSO exposure in Y-79 cells in vitro decreases the Do value of retinoblastoma cells. The SER of 0.01 mM and 0.05 mM BSO for 24 h under the hypoxic condition is 1.21 and 1.36, respectively. Based on these observations, the authors conclude that BSO toxicity on retinoblastoma cells depends on the characteristics of cell line and that BSO can increase hypoxic retinoblastoma cells' radiosensitivity in vitro. Further study of BSO radiosensitization on retinoblastoma in vivo using nude mouse xenograft is needed.

Treatment of intra-articular fractures with shape memory compression staples

The management of intra-articular fractures remains difficult. Shape memory compression staples fulfil nearly all the special treatment requirements of intra-articular fractures. Early bone union and 93.5 per cent satisfactory function were achieved in a series of 121 cases. Stable fixation, 'early' movement and continuous compressive force produced by the staple are the main factors contributing to good results.

Crystallization of the OP-G2 Fab fragment: a fibrinogen mimic with specificity for the platelet glycoprotein IIb/IIIa

The OP-G2 monoclonal antibody binds to the platelet integrin, gpIIb/IIIa, in a mode that mimics fibrinogen binding. The specificity of this antibody is mediated by the third complementarity-determining region (CDR3) loop of the immunoglobulin heavy chain which contains a sequence (RYD) related to the RGD recognition sequence of fibrinogen. The OP-G2 Fab fragment has been crystallized by vapor diffusion from solutions containing polyethylene glycol and imidazole malate (pH 5.6). The crystals belong to space group P2(1)2(1)2 with a = 93.1, b = 83.8 and c = 53.7 A. One Fab molecule is present in the asymmetric unit. A complete data set to 2.0 A resolution has been collected.