Search

The distribution coefficients of uranium, nitric acid and 8 elements simulating fission products were obtained from the concentrated aqueous solutions of nitrates, whose nitrate ion concentrations were 4–15 mol dm−3. The relationships among the distribution coefficient of uranium, the nitrate ion concentration in the aqueous phase, and the concentration of tri-n-butylphosphate uncombined with nitrates in the organic phase were obtained from the data.

As a new damping material, the authors first developed a Zn-22wt.%-Al eutectoid alloy with ultra-fine grains exhibiting superplasticity at room temperature by means of thermomechanical controlling processes (TMCPs). The Zn-Al alloy has a few advantages such as low work-hardening rate and high ductility over a conventional seismic damping material, for instance, a low-yield-point steel. In addition, Zn-Al alloys are environment-conscious because of no harmful metal like Pb. However, when Zn-Al alloys are subjected to plastic deformation, since its work hardening is small, plastic deformation proceeds locally so that required absorption energy cannot be sufficiently obtained, and local fracture and local deformation instability can take place easily, which is the intrinsic characteristic of superplastic materials. Therefore we attempted to develop a shear panel type, a brace type damper for tall buildings and a bending type damper for Japanese wooden houses using FEM analysis in order to minimize localized strain and local deformation and to determine the optimum shape for this Zn-Al superplastic seismic damper. As a result, an ecological and high-energy absorption seismic dampers, so-called “maintenance-free seismic damper,” was successfully developed.

Abstract: Objective: The aim of this survey was to compare the seroprevalences ofHelicobacter Pylori (H. pylori) and chronic atrophic gastritis (CAG) in Tanzania and the Dominican Republic, both of which are tropical countries, and thereafter compare the prevalences in Tanzania and the Dominican Republic with prevalences from our previous studies done in Japan (1991) and China (1996/97). Methods: Community-based study in which 573 inhabitants of Tanzania and 1,215 inhabitants of the Dominican Republic answered detailed questionnaires on upper digestive tract diseases, and then underwent screening for gastric cancer by serum pepsinogen and testing for antibody toH. pylori. Results: After adjusting to the ‘Age-Standardized Rate’ (ASR) using the world population in 1995, the seroprevalences ofH. pylori infection in male and female subjects for Tanzania (m=85.3% & f=88.2%) were very high compared to those for the Dominican Republic (m=63.5% & f=62.4%) and Japan (m=62.0% & f=46.8%), and similar to those of China (m=78.0% & f=77.3%). Also, the agestandardized prevalences of CAG in males and females for Tanzania (m-0.237& f=0.458). were higher than those of the Dominican Republic (m=0.168 & f=0.211) and China (m=0.111 & f=0.107) and compared well with those of Japan (m=0.266 & f=0.352). Conclusions: Although Tanzania and the Dominican Republic are both developing countries, Tanzania had a very high age-standardized prevalence ofH. pylori and CAG compared to that of the Dominican Republic, which showed a trend similar to that of Japan.

Not Available

We introduce a relaxation collision operator for a mixture of gases which satisfies several fundamental properties. Different BGK type collision operators for gas mixtures have been introduced earlier but none of them could satisfy all the basic physical properties: positivity, correct exchange coefficients, entropy inequality, indifferentiability principle. We show that all those properties are verified for our model, and we derive its Navier–Stokes limit by a Chapman–Enskog expansion.

Neurophysiological Changes in Rats Subchronically Treated with Styrene or Its Metabolites: Junichi Misumi, et al.Department of Public Health and Hygiene, Oita Medical University—The purpose of this study was to clarify the causative agent(s) in the peripheral neuropathy induced by styrene. Styrene 600 or 300, and its metabolites; hippuric acid 600 or 300; mandelic acid 300; styrene oxide 100; mg/kg were subcutaneously injected into rats for 10 to 12 wk. The changes in maximum sensory conduction velocity (SCV), maximum motor conduction velocity (MCV), and motor distal latency (DL) in the rat’s tail nerve were tested. Compared with the control group, decreases in MCV, SCV, and an increase in DL were observed in the rats injected with styrene 600, styrene oxide 100 and mandelic acid 300 mg/kg. No significant changes were found in the rats treated with hippuric acid 300 or 600 mg/kg. The MCV and SCV values in the styrene oxide 100 and mandelic acid 300 mg/kg groups were significantly lower, and DL values were significantly longer than those in the styrene 600 mg/kg group. It is presumed that the neuropathy caused by styrene is related to the neurotoxicity of its intermediate metabolites, namely mandelic acid and styrene oxide. It appears that the neurotoxicity of mandelic acid needs to be further evaluated in styrene-produced neuropathy.

Neurophysiological Changes in Rats Subchronically Treated with Styrene or Its Metabolites: Junichi Misumi, et al.Department of Public Health and Hygiene, Oita Medical University—The purpose of this study was to clarify the causative agent(s) in the peripheral neuropathy induced by styrene. Styrene 600 or 300, and its metabolites; hippuric acid 600 or 300; mandelic acid 300; styrene oxide 100; mg/kg were subcutaneously injected into rats for 10 to 12 wk. The changes in maximum sensory conduction velocity (SCV), maximum motor conduction velocity (MCV), and motor distal latency (DL) in the rat's tail nerve were tested. Compared with the control group, decreases in MCV, SCV, and an increase in DL were observed in the rats injected with styrene 600, styrene oxide 100 and mandelic acid 300 mg/kg. No significant changes were found in the rats treated with hippuric acid 300 or 600 mg/kg. The MCV and SCV values in the styrene oxide 100 and mandelic acid 300 mg/kg groups were significantly lower, and DL values were significantly longer than those in the styrene 600 mg/kg group. It is presumed that the neuropathy caused by styrene is related to the neurotoxicity of its intermediate metabolites, namely mandelic acid and styrene oxide. It appears that the neurotoxicity of mandelic acid needs to be further evaluated in styrene‐produced neuropathy.

To ascertain the relationship among 2,5-hexanedione (2,5-HD) concentrations in nerve, serum and urine, rats were injected subcutaneously with 2.6 mmol/kg 2,5-HD alone, or together with 2.6 or 13.0 mmol/kg of methyl ethyl ketone, acetone and toluene. 2,5-HD concentrations in sciatic nerve (NC), serum (SC) and urine (UC) were determined, and the linear regression between each two of NC, SC, and UC were calculated. There was good correlation between NC and SC, SC and UC in the 2,5-HD alone group, and good correlation between NC and SC in the co-treated groups. Co-treatment solvent had little effect on the relationship between SC and NC. 13.0 mmol/kg co-treated solvent tended to decrease the regression coefficients compared with 2.6 mmol/kg co-treated solvent. These results show that SC can be used in estimating NC in the 2,5-HD alone or co-treated groups, and UC can be used in estimating SC in the 2,5-HD alone group.

Repeated cutaneous applications of p‐hydroxylaminobenzene sulfonamide (PHABSA), which is a photo‐oxidation product of sulfanilamide (SNAm), sensitizes the guinea pig. By challenge with the substance, a marked cutaneous inflammatory reaction and an elevation of histamine level in the lesions are observed, although a single application of PHABSA to the non‐sensitized animals elicits neither a cutaneous reaction nor changes of histamine content.

Electrophysiological Changes Induced by Different Doses of 1‐Bromopropane and 2‐Bromopropane: Wenyuan Zhao, et al. Department of Public Health and Hygiene, Oita Medical University—To ascertain the neurotoxicity of 2‐bromopropane and 1‐bromopropane, three doses of 2‐bromopropane (1.1, 3.7 and 11.0 mmol/kg), two doses of 1‐bromopropane (3.7 and 11.0 mmol/kg), and a dose of 2,5‐hexanedione (2,5‐HD) as a positive reference (2.6 mmol/kg) dissolved in olive oil were subcutaneously injected into rats once a day, 5 d/wk for 4 weeks. A control group were injected with olive oil alone. The maximum motor conduction velocity (MCV) and the motor latency (ML) in rat tail nerve, as indexes of the electrophysiological changes, were investigated for 4 weeks. From 2 weeks after the injections, the MCV in the 1‐bromopropane and 2‐bromopropane‐treated groups began to decrease in a dose‐dependent fashion. These dose‐related decreases continued, and the MCV in the groups injected with 1‐bromopropane (11.0 mmol/kg) and 2‐bromopropane (3.7 and 11.0 mmol/kg) decreased significantly compared with that in the control group. The ML in the 1‐bromopropane and 2‐bromopropane‐treated groups increased in reverse correlation with the MCV decreases. The changes in ML occurred earlier than the MCV changes in the 1‐bromopropane and 2‐bromopropane‐treated groups. The potency of the peripheral neurotoxic changes induced by 1‐bromopropane and 2‐bromopropane at the doses used in the present study was weaker than that observed in the positive reference 2,5‐HD (2.6 mmol/kg) group.

Electrophysiological and Biochemical Effects of Exposure to 2,5‐Hexanedione on Peripheral Nerve in Experimental Diabetic Rats: Takashi Kimura,et al.Department of Public Health and Hygiene, Oita Medical University—Both 2,5‐ hexanedione (2,5‐HD) and diabetes mellitus (DM) cause peripheral neuropathy. Workers with asymptomatic DM could possibly be exposed to n‐ hexane converted to 2,5‐HD in liver. To clarify 2,5‐HD influences on peripheral nerves in DM, electrophysiological and biochemical changes in DM rats were compared in 2,5‐HD treated and untreated groups. Four groups of rats were studied: the Control group consisted of non‐diabetic rats treated with a placebo: the HD group, of non‐diabetic rats treated with 2.5‐HD; the DM group, of diabetic rats treated with a placebo: the DM+HD group, of diabetic rats treated with 2.5‐HD. 2,5‐HD was administered at 100 mg/kg/day, five days a week for 8 weeks. The motor nerve conduction velocity (MCV) and motor distal latency (DL) in the rat 's tails and glucose, fructose, sorbitol and myo‐ inositol levels in the sciatic nerves were measured. The MCV in the DM+HD group was significantly reduced from the 4th week compared with those in the other groups. 2,5‐HD had no influence on the levels of glucose, fructose, sorbitol and myo‐inositol in either the diabetic or non‐diabetic group. These results indicated that exposure to 2,5‐HD hastened the onset of peripheral neuropathy in experimental diabetic rats. This study indicates that 2,5‐HD in combination with DM enhances the neurotoxicity. But the mechanisms of the neurotoxic interactions between 2,5‐HD and DM are still unknown. It can be hypothesized that workers with hyperglycemia can suffer from neuropathy due to exposure to n‐hexane earlier than those without hyperglycemia.

Changes in 2,5‐Hexanedione Concentration in the Sciatic Nerve, Serum and Urine of Rats Induced by Combined Administration of 2,5‐ Hexanedione or Methyl Ethyl Ketone: Kazuo Aoki, et al.Department of Public Health and Hygiene, Oita Medical University—To clarify whether there is a difference in the toxicokinetic changes in 2,5‐ hexanedione (2,5‐HD) on coadministration with acetone or methyl ethyl ketone (MEK), 108 rats were treated subcutaneously with 2,5‐HD at a dose of 2.6 mmol/kg alone (HD group), with 2,5‐HD and acetone both at 2.6 mmol/kg (HD + AC group), or with 2,5 ‐HD and MEK both at 2.6 mmol/kg (HD + MEK group). At 0.5, 1, 2, 4, 8, and 16 hours after injection, 2,5‐HD concentrations in serum, the sciatic nerve and urine (16 hours only) were determined and some toxicokinetic parameters were then estimated. The 2,5‐HD concentrations in serum and the sciatic nerve were significantly higher in both the coadministered groups at 16 hours, and the AUC (area under the serum or nerve concentration versus time curve) in serum and the sciatic nerve of both the coadministered groups increased significantly during 8 to 1 6 hours compared with the 2,5‐HD alone group. The differences in urinary 2,5‐HD concentrations among the three groups were at the marginal level for significance by ANOVA (p = 0.053), but the values for the total amount of urinary 2,5‐HD within 16 hours were not significantly different (p = 0.55) among the three groups. There were good correlations between 2,5‐HD concentrations in the sciatic nerve and those in serum in the three groups (r = 0.91, r = 0.91 and r = 0.85 for HD, HD + AC and HD + MEK groups, respectively). The ratios of 2,5‐HD concentration in the sciatic nerve/2,5‐HD concentration in serum were not significantly different among the three groups (0.17, 0.19 and 0.20 for HD, HD + AC and HD + MEK groups, respectively). The estimated biological halflife t1/2 in the HD + AC group was prolonged significantly as was that in the HD + MEK group when compared with that in the HD alone group. The retarded elimination of 2,5‐HD from serum seemed not to be directly related to urinary excretion in the coadministered groups. The present study revealed that the coadministration of 2,5‐HD with acetone produced similar toxicokinetic changes in serum and in the sciatic nerve as that with MEK. It was suggested that the retardation of disappearance of 2,5‐HD from serum and the sciatic nerve on administration of a combination of 2,5‐HD with acetone was not related to urinary excretion but to the overloading of the metabolic capacity of 2,5‐HD in the liver.

Abstract: Objective: To clarify changes in the serum, nerve, and urinary levels of 2,5-hexanedione (2,5-HD) in rats on coadministration with methyl ethyl ketone (MEK), acetone (AC), and toluene (TO). Method: 2,5-HD alone or combined with MEK, AC, and TO was injected subcutaneously into a total of 306 male Wistar rats. The rats were divided as follows into 7 groups: (1) 2.6 mmol/kg 2,5-HD alone (HD) and (2) 2.6 mmol/kg 2,5-HD combined with 2.6 mmol/kg MEK (HD + MEK), (3) with 2.6 mmol/kg AC (HD + AC), (4) with 2.6 mmol/kg TO (HD + TO), (5) with 13.0 mmol/kg MEK (HD + 5MEK), (6) with 13.0 mmol/kg AC (HD + 5AC), and (7) with 13.0 mmol/kg TO (HD + 5TO). 2,5-HD concentrations in the serum, sciatic nerve, and urine of rats were determined within 16 h of the injections and pharmacokinetic parameters were estimated. Results: It was observed that (1) the 2,5-HD concentration and AUC value (area under concentration versus time curve) determined in the serum and nerve increased significantly in the cotreated groups as compared with the HD group; (2) the effect MEK had in elevating the 2,5-HD concentration and AUC in the serum and nerve was stronger than that of AC, and the effect AC had was stronger than that of TO; (3) a dose increase from 2.6 to 13.0 mmol/kg for MEK and AC induced further increases in the 2,5-HD concentration and AUC determined in the serum and nerve; (4) elimination constants recorded for 2,5-HD (K e) from the serum and nerve decreased in all the cotreated groups, and the degree of the decrease correlated inversely with the elevation in 2,5-HD concentration and AUC in the serum and nerve; and (5) urinary 2,5-HD concentrations measured in the 13.0-mmol/kg cotreated groups increased in parallel with the elevation in serum 2,5-HD concentrations. Conclusion: Coadministration of 2,5-HD with MEK, AC, or TO can increase the concentration and AUC of 2,5-HD in serum and the sciatic nerve, and these increases can be further enhanced by an increase in the concomitant doses of MEK and AC.

Changes in 2,5-Hexanedione Concentration in the Sciatic Nerve, Serum and Urine of Rats Induced by Combined Administration of 2,5-Hexanedione or Methyl Ethyl Ketone: Kazuo Aoki, et al.Department of Public Health and Hygiene, Oita Medical University—To clarify whether there is a difference in the toxicokinetic changes in 2,5-hexanedione (2,5-HD) on coadministration with acetone or methyl ethyl ketone (MEK), 108 rats were treated subcutaneously with 2,5-HD at a dose of 2.6 mmol/kg alone (HD group), with 2,5-HD and acetone both at 2.6 mmol/kg (HD + AC group), or with 2,5-HD and MEK both at 2.6 mmol/kg (HD + MEK group). At 0.5, 1, 2, 4, 8, and 16 hours after injection, 2,5-HD concentrations in serum, the sciatic nerve and urine (16 hours only) were determined and some toxicokinetic parameters were then estimated. The 2,5-HD concentrations in serum and the sciatic nerve were significantly higher in both the coadministered groups at 16 hours, and the AUC (area under the serum or nerve concentration versus time curve) in serum and the sciatic nerve of both the coadministered groups increased significantly during 8 to 1 6 hours compared with the 2,5-HD alone group. The differences in urinary 2,5-HD concentrations among the three groups were at the marginal level for significance by ANOVA (p = 0.053), but the values for the total amount of urinary 2,5-HD within 16 hours were not significantly different (p = 0.55) among the three groups. There were good correlations between 2,5-HD concentrations in the sciatic nerve and those in serum in the three groups (r = 0.91, r = 0.91 and r = 0.85 for HD, HD + AC and HD + MEK groups, respectively). The ratios of 2,5-HD concentration in the sciatic nerve/2,5-HD concentration in serum were not significantly different among the three groups (0.17, 0.19 and 0.20 for HD, HD + AC and HD + MEK groups, respectively). The estimated biological half-life t1/2in the HD + AC group was prolonged significantly as was that in the HD + MEK group when compared with that in the HD alone group. The retarded elimination of 2,5-HD from serum seemed not to be directly related to urinary excretion in the coadministered groups. The present study revealed that the coadministration of 2,5-HD with acetone produced similar toxicokinetic changes in serum and in the sciatic nerve as that with MEK. It was suggested that the retardation of disappearance of 2,5-HD from serum and the sciatic nerve on administration of a combination of 2,5-HD with acetone was not related to urinary excretion but to the overloading of the metabolic capacity of 2,5-HD in the liver.

Electrophysiological and Biochemical Effects of Exposure to 2,5-Hexanedione on Peripheral Nerve in Experimental Diabetic Rats: Takashi Kimura,et al.Department of Public Health and Hygiene, Oita Medical University—Both 2,5-hexanedione (2,5-HD) and diabetes mellitus (DM) cause peripheral neuropathy. Workers with asymptomatic DM could possibly be exposed to n-hexane converted to 2,5-HD in liver. To clarify 2,5-HD influences on peripheral nerves in DM, electrophysiological and biochemical changes in DM rats were compared in 2,5-HD treated and untreated groups. Four groups of rats were studied: the Control group consisted of non-diabetic rats treated with a placebo: the HD group, of non-diabetic rats treated with 2.5-HD; the DM group, of diabetic rats treated with a placebo: the DM+HD group, of diabetic rats treated with 2.5-HD. 2,5-HD was administered at 100 mg/kg/day, five days a week for 8 weeks. The motor nerve conduction velocity (MCV) and motor distal latency (DL) in the rat’s tails and glucose, fructose, sorbitol and myo-inositol levels in the sciatic nerves were measured. The MCV in the DM+HD group was significantly reduced from the 4th week compared with those in the other groups. 2,5-HD had no influence on the levels of glucose, fructose, sorbitol and myo-inositol in either the diabetic or non-diabetic group. These results indicated that exposure to 2,5-HD hastened the onset of peripheral neuropathy in experimental diabetic rats. This study indicates that 2,5-HD in combination with DM enhances the neurotoxicity. But the mechanisms of the neurotoxic interactions between 2,5-HD and DM are still unknown. It can be hypothesized that workers with hyperglycemia can suffer from neuropathy due to exposure to n-hexane earlier than those without hyperglycemia.

Electrophysiological Changes Induced by Different Doses of 1-Bromopropane and 2-Bromopropane: Wenyuan Zhao, et al. Department of Public Health and Hygiene, Oita Medical University—To ascertain the neurotoxicity of 2-bromopropane and 1-bromopropane, three doses of 2-bromopropane (1.1, 3.7 and 11.0 mmol/kg), two doses of 1-bromopropane (3.7 and 11.0 mmol/kg), and a dose of 2,5-hexanedione (2,5-HD) as a positive reference (2.6 mmol/kg) dissolved in olive oil were subcutaneously injected into rats once a day, 5 d/wk for 4 weeks. A control group were injected with olive oil alone. The maximum motor conduction velocity (MCV) and the motor latency (ML) in rat tail nerve, as indexes of the electrophysiological changes, were investigated for 4 weeks. From 2 weeks after the injections, the MCV in the 1-bromopropane and 2-bromopropane-treated groups began to decrease in a dose-dependent fashion. These dose-related decreases continued, and the MCV in the groups injected with 1-bromopropane (11.0 mmol/kg) and 2-bromopropane (3.7 and 11.0 mmol/kg) decreased significantly compared with that in the control group. The ML in the 1-bromopropane and 2-bromopropane-treated groups increased in reverse correlation with the MCV decreases. The changes in ML occurred earlier than the MCV changes in the 1-bromopropane and 2-bromopropane-treated groups. The potency of the peripheral neurotoxic changes induced by 1-bromopropane and 2-bromopropane at the doses used in the present study was weaker than that observed in the positive reference 2,5-HD (2.6 mmol/kg) group.

Upon the addition of histidine and histamine, the copper containing monoamine oxidase (MAO) catalyzes the oxidation ofl-ascorbic acid (AsA) by dissolved oxygen, in which the consumed oxygen was finally converted to hydrogen peroxide, according to Michaelis–Menten kinetics (Km= 1.97 mm, upon the addition of 5 × 10−5m l-histidine at 35°C and pH 8.5). The amount of oxygen consumption depended on the amount of histidine and histamine added, and specific responses over other amines were observed when the oxygen electrode modified with immobilized MAO membrane was used in the 0.1mTris buffer containing AsA. The calibration curves ofl-histidine and histamine at 4 mmAsA exhibit linearity in the concentration range from 5 × 10−7to 5 × 10−5m l-histidine and 5 × 10−6to 1 × 10−3mhistamine, with detection limit of 3 × 10−7m l-histidine and 3 × 10−6mhistamine, respectively. The ESR signal of copper(II) in active site of MAO at 77K was apparently changed upon the addition ofl-histidine and histamine indicating that exogenous histidine and histamine bound to the copper site of enzyme and lead to the structural change in active site.

A semi-infinite expanse of a binary mixture of a vapor and a noncondens-able gas in contact with an infinite plane condensed phase of the vapor is considered in the case where there is a uniform high-speed flow of the vapor toward the condensed phase at infinity and steady condensation of the vapor is taking place on the condensed phase. The steady behavior of the gas mixture is investigated on the basis of the Boltzmann equation. Under the assumption that the molecules of the noncondensable gas are mechanically identical with the vapor molecules, the problem, which is originally a boundary-value problem of two coupled nonlinear equations, is reduced to two problems of single equations: a nonlinear problem for the total mixture, which is equivalent to the condensation problem for a pure vapor studied extensively by the authors in the previous papers, and a linear homogeneous problem for the non-condensable gas. After the discussion of the general feature of the problem, the numerical computation of the latter problem is carried out by a model Boltzmann equation [V. Garzó et al., Phys. Fluids A 1, 380 (1989)]. Thus, the steady behavior of the vapor and the noncondensable gas is clarified. In particular, the effect of the amount of the noncondensable gas on the relation among the parameters of the condensed phase and of the vapor at infinity that allows a steady solution is obtained.

Changes in acid phosphatase and β‐glucuronidase activity were observed in lesions in cases of primary irritant and allergic contact dermatitis caused by dinitrochlorobenzene in guinea pigs.

The abdominal skin of guinea pigs was irradiated by a Xenon short arc lamp with glass filters. Acid phosphatase and β‐glucuronidase activity increased in the irradiated skin. The change of acid phosphatase is slow and mild in intensity, while that of β‐glucuronidase is quick and high in degree. The activity of acid phosphatase is influenced equally by light with filters of UV‐25, UV‐27, UV‐29, and UV‐31, while that of β‐glucuronidase is affected more mildly by light with a UV‐31 filter than with any of the other three filters.

We realized a surface stabilized ferroelectric liquid crystal display with high contrast ratio and high transmittance using a conventional rubbing method. Such remarkable electrooptical properties are based on the switching between uniform states in a cell treated with an AC electric field in the SmC*. It was confirmed by X-ray diffraction that the treatment caused a permanent change in the smectic layer structure from a chevron to a quasi-bookshelf structure. An example of multiplexing is also displayed.

Controllable well-insulated gaps between electrodes can be obtained by anodic oxidation of the edges of the regions of an Al film covered by photo resist. This technique is used to fabricate surface acoustic wave narrow gap interdigital transducers (NG-IDTs) and narrow gap floating electrode type unidirectional transducers (NG-FEUDTs). Experimental results indicate that the SAW NG-IDTs and NG-FEUDTs operate in the 10GHz range and have an electrode width of less than 0.2 µm.