Fluoride profiles in dental calculus from Japanese, Chinese and British residents

Whether the fluoride concentrations and profiles differ in human dental calculus obtained from different countries was investigated. A total of 203 dental calculus deposits on 203 permanent teeth from residents (mean age, 52.1 years) of Nagoya (Japan), Shanghai (China), Leeds (Great Britain) and the Wuhan mountainous area (China, fluoridated area) were analysed. An abrasive microsampling procedure was used to examine fluoride distribution. There were five types of fluoride profiles in dental calculus in each area/country (designated types L, J, U, T, W). In supragingival calculus, type L (highest in the outermost layers) and type J (highest in the innermost layers) both had significantly higher values than type U (high in the surface and innermost layers) but were relatively identical. In subgingival calculus, type W (high in the outermost, mid and innermost layers) was characteristics. Calculus from the Wuhan mountainous area (fluoridated) had the highest fluoride concentration, followed by Leeds (non-fluoridated), and Nagoya and Shanghai (non-fluoridated) calculus had the lowest. Fluoride concentrations in supragingival calculus were higher in teeth extracted because of periodontal diseases than dental caries. It is concluded that fluoride concentrations and distribution in dental calculus differ from country to country, probably due to different fluoride environments.     

Microstructure and Crystallographic Orientation of Anatase Coatings Produced from Chemically Modified Titanium Tetraisopropoxide

Poly(ethylene glycol) was coordinated to a structure formed by the controlled hydrolysis and polycondensation reactions of titanium tetraisopropoxide chelated with diethanolamine. From the resulting chemically modified precursor solution, anatase coatings consisting of nanometer-sized pores and grains with diameters of ∼30 nm and a preferred orientation along the c -axis were prepared on quartz-glass plates by a dip coating method. In contrast, anatase coatings consisting of submicrometersized pores and randomly orientated grains were prepared from the solution in which the poly(ethylene glycol) had been isolated.     

Involvement of apoptosis and cyclin D1 gene repression in growth inhibition of T-47D human breast cancer cells by methylglyoxal bis(cyclopentylamidinohydrazone)

In 2 forested areas near Belém (Para State, Brazil), 2 Haemagogus and 6 Sabethes species were marked released and recaptured in May 1989 and in April 1993. The recapture rates were high, 4.9 and 13.1% for Haemagogus and Sabethes spp., respectively. For Haemagogus janthinomys Dyar, females were recaptured until 27 d after release. The duration of the gonotrophic cycle was between 5.0 and 9.5 d and the survival rate was 0.90-0.92. Haemagogus leucocelaenus (Dyar & Shannon) was recaptured once, 21 d after release. Twelve Sabethes chloropterus (Von Humboldt) were recaptured, with a peak at 15-18 d; 1 female was recaptured at 44 d, indicating extended survival. Seven Sabethes amazonicus Gordon & Evans and 7 Sabethes cyaneus (F.) were recaptured, mostly at 14-39 d. These results indicate that Haemagogus and Sabethes spp. have a gonotrophic cycle in nature longer than inferred from laboratory studies, and that cycle length varies seasonally. The capacity of these species to sustain epizootics or epidemics of arboviruses may depend on local weather, with risk greatest at the end of the rainy season.     

Diosgenin attenuates inflammatory changes in the interaction between adipocytes and macrophages

Obese adipose tissues are characterized by the enhanced infiltration of macrophages. It is considered that the paracrine loop involving monocyte chemoattractant protein‐1, tumor necrosis factor‐α, and the free fatty acid between adipocytes and macrophages establishes a vicious cycle that aggravates inflammatory changes and insulin resistance in obese adipose tissues. Diosgenin, a saponin aglycon found in a variety of plants, has anti‐inflammatory properties. In the present study, we examined the effect of diosgenin on the inflammatory changes in the interaction between adipocytes and macrophages. A coculture of 3T3‐L1 adipocytes and RAW 264 macrophages markedly enhanced the production of tumor necrosis factor‐α, monocyte chemoattractant protein‐1, and nitric oxide compared with the sum of their single cultures; however, treatment with diosgenin inhibited the production of these proinflammatory mediators. Diosgenin also suppressed the inflammation in RAW 264 macrophages that was induced by the conditioned medium derived from 3T3‐L1 adipocytes. Furthermore, diosgenin inhibited the conditioned medium‐induced degradation of inhibitor κB and the phosphorylation of c‐jun N‐terminal kinase in macrophages. These results indicate that diosgenin exhibits anti‐inflammatory properties in the interaction of adipocytes and macrophages by inhibiting the inflammatory signals in macrophages. Diosgenin may be useful for ameliorating the inflammatory changes in obese adipose tissues.     

Laparoscopic cholecystectomy in cirrhotic patients: expanding indications

Cirrhosis, portal hypertension, and bleeding disorders are being considered as relative or absolute contraindications to laparoscopic cholecystectomy (LC). This report describes four cirrhotic patients with clinical portal hypertension in three and mild to severe bleeding tendency in all. Laparoscopic cholecystectomy was uniformly successful in these patients with no complications. If the surgeon exercises extreme caution in securing hemostasis and does not overlook some details concerning patient management, LC can be efficiently and safely performed in cirrhotic patients. Compared with open cholecystectomy, LC may be even more advantageous concerning the virtual elimination of incision-related complications. Our preliminary experience is encouraging and suggests more liberal use of LC in cirrhosis-portal hypertension-bleeding tendency disease complex.     

High-Temperature Toughness and Tensile Strength of Whisker-Reinforced Silicon Nitride

The R -curve behavior of hot-pressed silicon nitride reinforced with silicon carbide whiskers is investigated from room temperature to 1300°C using the chevron-notch bend test. The bridging stress, estimated from increment of fracture resistance in the rising R -curve, is discussed in relation to tensile strength measured with various displacement rates at 1300°C. The reinforcing whiskers provide most of the tensile strength in the creep-deformation range at 1300°C. The whiskers appear to bear a great deal of the applied tensile stress during slow crack growth.     

Bubble formation in cocurrently upward flowing liquid

The effects of liquid velocity, nozzle diameter, gas chamber volume and gas flow rate on volumes, shapes and growth curves of bubbles formed at a nozzle submerged in a cocurrently upward flowing liquid in a bubble column were experimentally investigated. The bubble volume decreases with increasing liquid flow velocity. The effect of liquid flow velocity on the volume of bubble increases with an increase in the gas flow rate. To simulate bubble formation at a nozzle submerged in cocurrently upward flowing liquid, a revised non-spherical bubble formation model was proposed. Bubble volumes, bubble growth curves and shapes experimentally obtained in this study, as well as in previous experimental studies, are well predicted by the present model.     

Electrospinning processed nanofibrous TiO(2) membranes for photovoltaic applications

We have recently fabricated dye-sensitized solar cells (DSSCs) comprising nanofibrous TiO(2) membranes as electrode materials. A thin TiO(2) film was pre-deposited on fluorine doped tin oxide (FTO) coated conducting glass substrate by immersion in TiF(4) aqueous solution to reduce the electron back-transfer from FTO to the electrolyte. The composite polyvinyl acetate (PVac)/titania nanofibrous membranes can be deposited on the pre-deposited thin TiO(2) film coated FTO by electrospinning of a mixture of PVac and titanium isopropoxide in N,N-dimethylformamide (DMF). The nanofibrous TiO(2) membranes were obtained by calcining the electrospun composite nanofibres of PVac/titania as the precursor. Spectral sensitization of the nanofibrous TiO(2) membranes was carried out with a ruthenium (II) complex, cis-dithiocyanate-N,N(')-bis(2,2(')-bipyridyl-4,4(')-dicarboxylic acid) ruthenium (II) dihydrate. The results indicated that the photocurrent and conversion efficiency of electrodes can be increased with the addition of the pre-deposited TiO(2) film and the adhesion treatment using DMF. Additionally, the dye loading, photocurrent, and efficiency of the electrodes were gradually increased by increasing the average thickness of the nanofibrous TiO(2) membranes. The efficiency of the fibrous TiO(2) photoelectrode with the average membrane thickness of 3.9?μm has a maximum value of 4.14%.