Nitroarene concentrations and direct-acting mutagenicity of diesel exhaust particulates fractionated by silica-gel column chromatography

Diesel exhaust particulates were extracted with benzene-ethanol (3:1, v/v) and separated into five fractions by silica-gel column chromatography. Direct-acting mutagenic activity was assayed by the Ames test using the Salmonella typhimurium YG1024 strain. The total activity of five fractions was about four times greater than that of the crude extract, suggesting that the activities in the fractions were suppressed in the crude extract. Strong activity was observed in fraction 4 which was eluted with dichloromethane (61.5% of the total activity) and fraction 5 which was eluted with ethanol (35.3%). Nitropolycyclic aromatic hydrocarbons (NPAHs) were determined by high-performance liquid chromatography with chemiluminescence detection. They were found mainly in fraction 4, although one NPAH was in fraction 3 which was eluted with n-hexane-dichloromethane (3:1, v/v). Based on these results, 53.1% of the activity in fraction 4 was attributed to NPAHs. The contribution of 1-nitropyrene and 1,3-, 1,6- and 1,8-dinitropyrenes was great and that of the other NPAHs was small. The mutagenic compound in fraction 5 was not identified. Fractions 1 and 2, which were eluted with n-hexane, and fraction 3 suppressed the activity of fraction 4. Polycyclic aromatic hydrocarbons in fractions 2 and 3 were considered as possible suppressors of NPAHs.     

BLM (the causative gene of Bloom syndrome) protein translocation into the nucleus by a nuclear localization signal

Bloom syndrome (BS) is a rare genetic disorder characterized by small body size, sun sensitivity, immunodeficiency and a high predisposition to various types of cancer. BLM was identified as the causative gene for BS, and BLM protein is homologous to DNA helicase. There are two putative nuclear localization signals (NLSs) within amino acid residues 1334-1349 in the C-terminus of the BLM protein, which has the distinctive structure of two basic residue arms separated by a spacer. The entire coding or deleted BLM sequences of various sizes were ligated into an enhanced green fluorescent protein (EGFP) vector and transfected into HeLa cells. The EGFP vector harboring the entire BLM coding sequence was transported to the nucleus. The BLM protein truncated at 1341 amino acid, containing an intact helicase domain and only one proximal arm, was not transported to the nucleus. The BLM protein truncated at 1357 amino acid, containing an intact helicase domain and two arms, was transported to the nucleus. The EGFP vector harboring DNA fragments encoding a protein having only the distal arms of basic amino acids in the C-terminus was also transported to the nucleus. The truncated BLM proteins corresponding to previously reported mutated BLM proteins were retained in the cytoplasm or both the cytoplasm and the nucleus as was the EGFP vector with no insert. These results show that the BLM protein translocates into the nucleus and that the distal arm of the bipartite basic residues in the C-terminus of the BLM protein is essential for targeting the nucleus.     

In-situ observation of faceted growth of benzophenone single crystals

Melt growth of benzophenone was in-situ observed under various cooling rate and temperature gradient. The melt growth experiments were performed for various cooling rate of melt and various temperature gradients. The movement of growth interface with time was measured for various growth faces such as (001), (101) and (011) and the growth rates of the respective faces were calculated. It was found that the growth rate of all the faces increased with cooling rate of the melt. Steady state growth was observed in the experiments with low temperature gradient while, the steep gradient leads to unstable growth of crystal. The observed growth rate variation was explained using the attachment energy model.     

Numerical simulation of fracture of model Al-Si alloys

Hypoeutectic Al-Si alloys consist of primary α-Al and Al-Si eutectic phases and show typical elasticplastic fracture. To understand their fracture behavior, fracture processes were simulated using an elastic-plastic finite-element method. The validity of the J-integral-based criterion was verified and applied to the simulations. A complicated model was used to simulate the fracture in an idealized dendritic microstructure, and four simplified models were intended to more clearly understand the interaction between a crack and individual α phases. Results show that the crack is attracted to the soft α phase when passing by the α phase, whereas it is repelled when the α phase is close in front of or behind the crack tip. The presence of α phase close in front of or behind the crack tip leads to an amplification of the driving force. However, the α phase beside the tip reduces the driving force. Furthermore, the fracture behavior is mainly affected by the adjacent α phase on one side around the crack tip, while the remote α phase on the opposite side has an offsetting effect. The local stress-strain fields were examined to analyze the simulated behavior. The simulated crack-growth path in the dendritic model was compared and verified with the experimentally observed path.     

Directional characteristics of radiation reflection on rough metal surfaces with description of heat transfer parameters

In this paper we clarify directional characteristics of thermal radiation reflection on rough metal surfaces and establish a technique for determining the parameters for heat transfer computation of radiation energy exchange among surfaces. Directional distribution of bidirectional reflectance ρ of surfaces of root‐mean‐square roughness Σ = 0.1 to 1 µm to the irradiation of a visible laser of wavelength λ = 0.6328 µm and to that of an infrared laser of λ = 3.39 µm is investigated experimentally. The optical roughness (Σ/λ) ranges from 0.028 to 1.27. A measure of the magnitude of specular reflection is presented. A model for describing the ρ distribution is presented, and the experimental results of the ρ distribution are analyzed quantitatively and systematically to determine the values of the specular reflection component R_s and the perfect‐diffuse reflection component R_d of the hemispherical reflectance R_H, which are input parameters for radiation heat transfer computation. © 2002 Scripta Technica, Heat Trans Asian Res, 31(2): 76–88, 2002; DOI 10.1002/htj.10008     

The effect of pituitary adenylate cyclase activating polypeptide (PACAP) on amylase secretion from guinea pig pancreatic acini

Beta-lactamase production is one of the major mechanisms of resistance amongst bacteria especially the enteric bacilli. The purpose of this study is to assess the in-vitro activity of Sulperazon, a combination of cefoperazone and an irreversible beta-lactamase inhibitor, sulbactam, against the cefoperazone resistant isolates of aerobic gram-negative bacilli. A total of 92 such strains were tested. It was found that at a concentration of < or = 8 mg/l of sulbactam added to cefoperazone 82% of Klebsiella spp, 100% of E. coli, 100% of Enterobacter spp, 33% of Pseudomonas aeruginosa, 67% of Pseudomonas spp and 62% of Acinetobacter spp that were resistant to cefoperazone alone were susceptible to the combination. Hence it is concluded that the addition of sulbactam to cefoperazone does expand the spectrum of the in-vitro activity of cefoperazone.     

Tumor necrosis factor alpha-mediated tumor regression by the in vivo transfer of genes into the artery that leads to tumors

We report that tumor necrosis factor (TNF) alpha induced a strong antitumor immune reaction when it was produced in arteries leading to tumors by gene transfer in vivo. We used a mouse model carrying a sarcoma-180 tumor in the right footpad and injected the fusogenic liposomes encapsulating the human TNF-alpha gene into the right femoral artery. Under this condition, human TNF-alpha was detected only in the artery leading to the tumor and in the tumor. There was a significant regression in tumor growth when the TNF-alpha gene was delivered into the right femoral artery, with 4 of 11 mice completely cured. No regression was observed when the TNF-alpha gene was delivered into the left femoral artery or into the tumor or when the luciferase gene was administered. Tumor regression was inhibited by the injection of anti-TNF-alpha, anti-CD4, or anti-CD8 monoclonal antibody, and CD8+ T cells accumulated in the tumors of TNF-alpha-treated mice. These results suggest that TNF-alpha expressed locally in the arteries leading to tumors efficiently suppresses tumor growth through reinforcement of an antitumor immune reaction. The significance of this phenomenon for cancer gene therapy was discussed.     

Discrepancy between surgeon''s binocular parallax perception and manipulation in the neurosurgical operation

The present study was undertaken after the detection of one case of cutaneous leishmaniasis with presumed infection in one of the three remaining wooded areas in the urban area of the city of Maringá, Southern Brazil; also in view of the lack of knowledge about sand flies and their behavior. From June to September, 1995, sand flies were caught with Falc?o traps during the night in the remaining wooded areas (Parque do Ingá, Bosque Dois and Horto Florestal). A total of 2,907 sand flies were caught in Parque do Ingá; 1,723 of them were aught in forest traps and 1,184 in wild animal shelter traps at the zoo. The results show that Lutzomyia whitmani is better adapted to the three areas under study and that it frequently occurs in wild animal shelters within the urban perimeter of Maringá.     

The relationship of a neonatal care center, a pediatric neurology division and a rehabilitation center for disabled children]

In alloxan-induced diabetic rats (Wistar, females, age 3-4 months of postnatal life) the large spectrum of fatty acids in blood serum, brain cortex, medulla oblongata and liver was studied. The fatty acids, using gas chromatography, were detected as methyl esters and the methods were published previously (Smídová and al. 1994). Alloxan (Merck) administered i.p., 140 mg/kg body weight, caused immediately elevation (three times) of blood sugar levels. On the 13th day the rats were killed. The results are as follows: a) In blood serum alloxan diabetes of cca two weeks duration caused a significantly increased participation of saturated FA and decreased participation of both polyunsaturated FA (n-3 and n-6). b) In brain cortex no differences between controls and diabetic rats in the indicated groups of FA were found. c) In the medulla oblongata an increased participation of polyunsaturated fatty acids n-6 was established. d) In hepatic tissue the increased participation of saturated FA as well as a decreased participation of FA n-6 was described. Analysing the main groups of FA we found especially in n-3 and n-6 FA several significant changes in single FA (a smaller pool of arachidonic acid in blood serum as well as in liver, decreased participation of docosahexaenoic acid in the brain cortex, etc.). The purpose and possible consequences of such changes are discussed.