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161.
We have calculated positron distributions on a series of BEDT-TTF based organic conductors, whose anion species are I3, Cu(NCS)2, Cu(CN)[N(CN)2], Cu[N(CN)2]Br and KHg(SCN)4. The results are discussed in connection with Fermiological studies by the positron annihilation method. Lifetimes and band masses of positrons have been calculated also.  相似文献   
162.
Resistance to wear of CBN grinding wheels is much higher than that of conventional (Al2O3) wheels. However, CBN grinding wheels are seldom used in gear grinding, when production scale is small, due to the difficulty in truing. Moreover, wear of the grinding wheel greatly affects the accuracy of tooth trace, in most cases. Considering this problem, the authors proposed new processes in which the accuracy of the tooth trace and tooth profile was hardly affected by wear of the wheel. While grinding was performed using a conventional method, a concave tooth-trace error of about 2 μm occurred after grinding only 30 teeth. In one of the proposed methods, the concave tooth trace error never occurred even when 2000 teeth were ground by the same wheel. In the third method, the CBN layer is effectively used for gear grinding by giving an additional motion which is independent of the tooth profile generating motion.  相似文献   
163.
A new process, the Non Anchor Coating Extrusion Laminating Process for producing an extrusion laminated film without any chemical primer, was investigated. Good adhesive properties were obtained by combining an ozone treatment of a molten polyethylene (LDPE) web and an activation treatment of the polyamide (ONy) substrate film. The adhesion mechanism induced by the new process was studied by FT-IR, ESCA and extraction of unreacted polyamide from the laminated samples. The peel strength between the ONy and LDPE laminated films produced with this process was greater than that for laminated film made with a conventional lamination process using anchor coating agents. A model of the adhesive mechanism is proposed. Hydrogen and covalent bonds through oxygenated functional groups are responsible for the enhanced adhesion.  相似文献   
164.
Imipenem/cilastatin sodium (IPM/CS) was administered to 102 patients with respiratory tract infections and lung cancer. Patients with other serious diseases were excluded and a total of 73 patients were enrolled. They were divided into 12 patients who underwent surgery (operated group) and 61 who did not (non-operated group); the latter group included 28 patients treated with anticancer agents or radiation therapy (treated group) and 33 untreated patients (untreated group). IPM/CS was effective in 75% of the patients, both with and without surgery. The drug was effective in 81% of the treated group, although many of the patients had Stage III or more advanced cancer, as well as bronchial occlusion. IPM/CS was also effective in 69% of the untreated group, although many of the patients have serious infections and a PS (Performance Status) of 3 or greater. Thus, IPM/CS treatment achieved good results. Bacteriological studies showed that 3 out of 4 strains in the operated group and 16 out of 18 in the non-operated group were eliminated. Safety was evaluated in all patients. Two patients (2%) experienced side effects and two others (2%) showed abnormal clinical findings, but the symptoms were mild and resolved after discontinuation or completion of therapy. In conclusion, IPM/CS was very effective for treating respiratory infections in patients with lung cancer.  相似文献   
165.
BACKGROUND: Many factors have been demonstrated to influence flexure of rigid contact lenses, but the contributions of surface tension and eyelid forces to flexure are not well understood. METHODS: We placed lenses on a model eye consisting of a polymethyl methacrylate (PMMA) base which could be flexed, and measured resultant flexure with a videokeratoscope. We varied the base toricity, sequence of measurement, and lens base curve. The effects of evaporation of the postlens fluid were also observed. RESULTS: Clinically significant flexure (> 0.50 D) occurred when two conditions were met: (1) the volume of the postlens space would increase if the lens unflexed, and (2) there was a paucity of fluid available to fill that space. Flexure was minimal (< or = 0.50 D) when ample fluid was present. CONCLUSION: Surface tension forces serve more to maintain rather than create rigid lens flexure. Our model helps to explain why steep-fitting lenses flex more and leads to several predictions for flexure, which appear generally to be obeyed.  相似文献   
166.
The basic helix-loop-helix (bHLH) factor Mash1 is expressed in the developing nervous system. Null mutation of Mash1 results in loss of olfactory and autonomic neurons and delays differentiation of retinal neurons, indicating that Mash1 promotes neuronal differentiation. Other bHLH genes, Math/NeuroD/Neurogenin, all expressed in the developing nervous system, have also been suggested to promote neuronal differentiation. In contrast, another bHLH factor, HES1, which is expressed by neural precursor cells but not by neurons, represses Mash1 expression and antagonizes Mash1 activity in a dominant negative manner. Forced expression of HES1 in precursor cells blocks neuronal differentiation in the brain and retina, indicating that HES1 is a negative regulator of neuronal differentiation. Conversely, null mutation of HES1 up-regulates Mash1 expression, accelerates neuronal differentiation, and causes severe defects of the brain and eyes. Thus, HES1 regulates brain and eye morphogenesis by inhibiting premature neuronal differentiation, and the down-regulation of HES1 expression at the right time is required for normal development of the nervous system. Interestingly, HES1 can repress its own expression by binding to its promoter, suggesting that negative autoregulation may contribute to down-regulation of HES1 expression during neural development. Recent studies indicate that HES1 expression is also controlled by RBP-J, a mammalian homologue of Suppressor of Hairless [Su(H)], and Notch, a key membrane protein that may regulate lateral specification through RBP-J during neural development. Thus, the Notch-->RBP-J-->HES1-Mash1 pathway may play a critical role in neuronal differentiation.  相似文献   
167.
Active surveillance of Vibrio parahaemolyticus infection among hospitalized patients in Calcutta, India, was initiated in January 1994. The incidence of cases of V. parahaemolyticus infection suddenly increased in February 1996 and has remained high since then. One hundred thirty-four strains of V. parahaemolyticus isolated from January 1994 to August 1996 were examined for serovar, the presence of the thermostable direct hemolysin gene (tdh) and tdh-related hemolysin genes (trh1 and trh2), production of urease, and antibiogram. Strains of the O3:K6 serovar appeared for the first time in February 1996. The O3:K6 serovar strains accounted for 50 to 80% of the strains isolated during the high-incidence period (February to August 1996). All of the serovar O3:K6 strains carried the tdh gene but not the trh genes and did not produce urease. All of the isolates except two were sensitive to all of the antibiotics tested. These and the results of analysis by an arbitrarily primed PCR method indicated that the O3:K6 serovar strains belong to a unique clone. When the O3:K6 serovar strains, isolated from travelers arriving in Japan from Southeast Asian countries, were compared by the arbitrarily primed PCR method, the strains isolated between 1982 and 1993 were distinct from Calcutta O3:K6 while the strains isolated in 1995 and 1996 were indistinguishable from the Calcutta O3:K6 strains. The results suggest that this unique O3:K6 clone may have become prevalent not only in Calcutta but also in Southeast Asian countries very recently. Not only the O3:K6 strains but also the non-O3:K6, tdh-bearing strains isolated in 1996 produced thermostable direct hemolysin at high levels, and thus the level of hemolysin produced does not appear to have influenced the high incidence of serovar O3:K6 strains.  相似文献   
168.
We studied the levels of carbohydrate antigen (CA 19-9, SLX, CA 50, Span-1, and Dupan-2) in serum, bronchoalveolar lavage fluid, and tissue from patients with benign bronchopulmonary disease. Patients had bronchiectasis, healed pulmonary tuberculosis, pulmonary fibrosis, or other diseases. Bronchoalveolar lavage fluid levels and immunohistochemical findings for lung tissue samples, in the absence of digestive and other diseases, suggested that elevated serum sialylated Lewis(A) (CA 19-9, CA 50, and Span-1) and Lewis(X) (SLX) antigen in patients with benign broncho-pulmonary disease are due to marked production of sialylated carbohydrate antigen in respiratory bronchioles. Common features of patients with benign bronchopulmonary disease include elevated serum carbohydrate antigen levels and bronchiectasis.  相似文献   
169.
We examined the effect of insertion of an exogenous gene on retinal function to assess the rationale of adenoviral vector-mediated gene transfer for future gene therapy. An adenoviral vector expressing bacterial LacZ (AdCALacZ) was injected into the eyes of adult rats either intravitreally (group A) or subretinally (group B), and the gene expression and retinal function were thus examined at different time points after gene transfer for 3 weeks. X-Gal histostaining showed that neural retinal cells were transfected in group A and that retinal pigment epithelial cells were transfected in group B. The gene transfer was more efficient in group B (54.4% of the fixed retinal area was stained) than in group A (10.4%). The electroretinogram (ERG) revealed retinal dysfunction in the AdCALacZ-transfected rats even at the stage in which the histological damage was not apparent by electron microscopy and immunohistochemical studies for cytokeratin, S-100 protein, and glial fibrillary acidic protein. The ERG change was correlated with the intensity of inflammation, and retinal function recovered to the original level by 3 weeks, along with a diminution of inflammation. Functional changes were more evident in eyes treated with AdCALacZ than in those infected with adenoviral vector with no exogenous gene; however, no histological difference was observed between these groups, indicating that the insertion of exogenous gene itself affects retinal function. The results showed that different kinds of retinal cells could be gene-transferred by an adenoviral vector, depending on the application method. The retinal dysfunction caused by each adenoviral transfection method was caused by inflammation and the insertion of exogenous gene, and this retinal dysfunction was recoverable. In future gene therapy, special attention should be given to the method of exogenous gene insertion in the retina.  相似文献   
170.
Pentoxifylline, which has immunomodulatory effects in addition to its better known rheologic effects, might potentiate the effectiveness of traditional immunosuppressive drugs. We therefore studied the suppressive effect of pentoxifylline in combination with clinically relevant concentrations of prednisolone, methylprednisolone, cyclosporine, tacrolimus, rapamycin, and mycophenolic acid on mitogen-stimulated lymphocytes from 29 patients with glomerular diseases. Inhibition of lymphocyte proliferation obtained with 10(-7) and 10(-8) mol/L concentrations of the glucocorticoids and with 300 ng/mL cyclosporine was significantly increased when each was combined with 5, 25, or 50 microg/mL of pentoxifylline. The additive inhibitory effect of pentoxifylline in combination with 10(-7) mol/L glucocorticoids was inversely proportional to the inhibitory effect of the 10(-7) mol/L concentration of glucocorticoid alone, suggesting that the less sensitive the patient's cells, the greater the potentiation by pentoxifylline. The greatest degree of potentiation by pentoxifylline occurred when combined with the lower (10(-8) mol/L) concentration of glucocorticoids. Pentoxifylline also significantly increased lymphocyte suppression in combination with 150 and 300 ng/mL concentrations of cyclosporine, 5 ng/mL of tacrolimus, 2.5 x 10(-7) mol/L mycophenolic acid, and 10 ng/mL of rapamycin. These in vitro results suggest that pentoxifylline might have steroid-sparing effects and contribute to improved clinical outcomes from immunosuppressive treatment of renal diseases.  相似文献   
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