An in vitro genotoxicity study of silver amalgam on Ames test

Silver amalgam/Silverfil Argentum® is a ‘Malaysian made amalgam’ has already been approved to be free from cytotoxicity, however its genotoxic effect has not been explored yet as biocompatible material. The objective of this study was to identify the genotoxic characteristic of silver amalgam by using Bacterial Reverse Mutation Assay (Ames test). This was a descriptive experimental study involving one strain of mutated Salmonella. The test material was evaluated in one mutated strain of Salmonella typhimurium TA1538 with and without an external metabolic activation system (S9 Mix). The bacteria were incubated for 48 hours at 37±0.5ºC before the colony growth or revertant colonies were counted. Data obtained were analyzed by using non-statistical method. The investigation of the genotoxic reaction on the test material revealed thatthe number of revertant colonies in both strains with and without S9 Mix were less than twice of the negative control even in the presence of high silver amalgam concentrations (5.0μg/ml). This study demonstratedthat the test material did not exhibit any mutagenic activity under the chosen conditions. Thus, silver amalgam could be considered to have no genotoxicity effect

ETS-1 oncoprotein expression is decreased in aggressive papillary transitional cell carcinoma of the urinary bladder: An immunohistochemical study

Introduction: ETS-1 proto-oncogene is a transcription factor that plays multiple roles in the process of oncogenesis and helps in the process of tumor invasion. ETS-1 oncoprotein correlation with high grade and invasive tumors is controversial; as it is found to be upregulated with some tumors and down regulated with others. Expression of ETS-1 in urinary bladder carcinoma (UBC) and its correlation with tumor differentiation and invasiveness are still under-investigated. So far, there is no reliable prognostic marker has been proved for detection of the tumor progression and recurrence.Objectives: To analyze the correlation between ETS-1 oncoprotein immunohistochemical expression and the different stages and grades of the primary papillary transitional cell carcinoma of the urinary bladder.Patients and methods: This is a retrospective cross sectional study that included archival material from 150 cancer cases and 24 control biopsies.Results: There was a decreased ETS-1 oncoprotein expression with increasing stage and grade of the tumor with a highly significant statistical correlation (P = 0.001). With the quantitative assessment of the immunohistochemical results and using ROC (receiver operating characteristics) curve, cut-off values were found, that were associated with high grade and muscle invasive tumors (≤30% and ≤20%, respectively).Conclusion: ETS-1 oncoprotein is down regulated with high grade and highly invasive urinary bladder papillary transitional cell carcinomas. This oncoprotein may be used as an independent prognostic marker to predict the aggressive papillary transitional carcinomas with high invasive potential. More studies are needed to confirm our results.Keywords: Papillary transitional cell carcinoma; ETS-1; Prognostic marker; Immunohistochemical; Stage; Grad

Studies in liquid phase adsorption at organic and inorganic surfaces

The first section of the thesis is concerned with adsorption by chitin. Lobster-shell chitin, prepared from the carapace of Nephrops norvegicus, has been used in quantitative adsorption studies with mineral and organic acids and sulphonated azo-dyes in aqueous solutions. In the case of acids the hydrogen ions are adsorbed initially on the acetylamino-groups in the substrate with a consequent swelling and breakage of inter-chain bonds owing to the pressure of solvated water around the resultant cationic centres. The actual amount of acid adsorbed is determined however by the ability of the anion to penetrate the structure. The hydrogen ion can penetrate it readily, but to preserve neutrality each adsorbed hydrogen ion must be accompanied by an anion, and owing to the high crystallinity of chitin the entry of anions is restricted, and in fact the amount adsorbed decreases linearly with the volume of the anion in any given series of acids with similar basic structure. Superimposed on this volume effect, however, is the effect of increased van der Waals attraction of the anion for chitin, with increase in the number of aromatic nuclei in the anion. Generally the affinity rises with increase in length of the conjugated system of the dye molecule. The ion-exchange adsorption process between the chitin and sulph-onate groups of the dye has a negligible apparent heat change, but the non-polar attraction of the remainder of the dye molecule does produce a heat change which increases with the non-polar affinity. Affinity measurements show that one sulphonate group in an adsorbed dye becomes associated with one of the cationic centres in chitin and that additional groups after the first are not so combined and remain dissolved in water, hence decreasing the affinity of the anion for the substrate. Hydrogen-bonding is also operative where there are potential hydrogen-bonding groups in the substrate, but seems to decrease with increasing acidity of the bath. The results of full elementary analyses suggest that chitin does not consist entirely of poly-N-acetylglucosamine, but that about one eighth of the amino-groups are unacetyl-ated. The next section of the thesis describes an investigation made to study and compare the adsorption mechanism of a variety of aromatic compounds, with and without hydrogenbonding groups, by cellulose and by chitin from water and from non-aqueous solvents. In absence of water polar nonionic compounds are adsorbed by both cellulose and chitin principally by hydrogen-bonding. In aqueous solution chitin adsorbs anionic solutes with potential hydrogen-bonding groups principally by ion-exchange and hydrogen-bond formation. Non-polar attraction is also operative in the case of large molecules. Cellulose seems to adsorb these compounds by non-polar attraction only, the affinity increasing with the size of the solute molecule and being independent of the presence therein of hydrogen-bonding- groups. Planar non-hydrogen-bonding anionic compounds are not adsorbed on chitin from alkaline solutions. Cellulose however does adsorb such compounds from either neutral or alkaline solution, because its attraction is non-polar and dependent not on hydrogen-bonding forces, but only on the presence of a highly conjugated system in the solute molecule This work was followed by a study of the adsorptive properties of graphite for organic solutes, mainly dyes, from aqueous and non-aqueous solvents. Rate measurements demonstrate a rapid adsorption and the short period required to reach equilibrium suggests that adsorption is entirely superficial. Basic dyes are quickly adsorbed, by electrostatic attraction. Anionic dyes appear to be adsorbed by physical attraction and the rate of adsorption is higher in the case of dyes which dissociate easily into single molecules. The surface area of graphite was determined by electron microscopy and the orientation of adsorbed molecules studied. At low concentration it seems that most of the compounds used form condensed monolayers. Sulphonated compounds appear to be so oriented that the sulphonate groups are as far away as possible from the graphite surface and non-ionic compounds lie flat so that they present a maximum surface area to the graphite

Effect of reagent type on the froth floatation of Sokoto phosphate ore

Effect of reagent type on the froth floatation of Sokoto phosphate ore for its beneficiation has been established. The samples of the Sokoto phosphate mineral ore used for the research work were sourced from mining locations in Dange-Shuni, Bodinga, Yabo, Wurno, and Rabbah Local Government Areas of Sokoto State. Size-Assay analysis conducted on scrubbed Sokoto Phosphates nodules revealed that nodules had a size distribution with 80% passing 29.3 mm. Flotation Tests using AERO704 (fatty Acid), Alkyl Hydroxamates, Melamine as collectors (alone or mixed with diesel), MIBC as frother, Calcium Hydroxide and Sulphuric Acid as pH regulators and Dextrin, Sodium Silicate and Aluminium Chloride as depressants produced poor P2O5 separation in the flotation products due to very poor liberation associated with very fine mineral grains. Based on the results obtained, AERO704 Collector gave the best result with aP2O5 recovery pH of 10

Effect of particle size on the froth floatation of Sokoto phosphate ore

Effect of particle size on the froth floatation of Sokoto phosphate ore for its beneficiation has been investigated and established. The research has been conducted using various reagents, pH(s) at different sieve size fractions. Bench scale flotation tests were carried out on -250+180μm, -180+106μm, -106+75μm, -75+45μm and -45+38μm particle size fractions after screening in order to determine the optimum flotation feed size distribution using 1 liter Denver flotation cell. The results of the scoping flotation studies using a conditioning Pulp Density of 60%Solids, pH9, 800g/t reagent dosage for AERO704 Promoter (Fatty Acid) and flotation pulp density of 28.5% Solids show that +106μm particle size gave the highest assay content of 20.4% P2O5 with a recovery of 76.2% compared to +38μm (19.9%P2O5 and recovery of 43.2%) and +180μm (19.4%P2O5 and 24.1% recovery) in their floats (concentrates) but with no perfect separation as the tailings fraction also contained similar grades with slight differences

Minimizing the Transaction Time Difference for NOMA-Based Mobile Edge Computing

Non orthogonal multiple access (NOMA) and mobile edge computing (MEC) are evolving as key enablers for fifth generation (5G) networks as this combination can provide high spectral efficiency, improved quality-of-service (QoS), and lower latency. This letter aims to minimize the transaction time difference of two NOMA paired users offloading data to MEC servers by optimizing their transmission powers and computational resources of severs using a successive convex approximation method. The equalization of transaction time for paired users reduces the wastage of both frequency and computational resources, and improves effective throughput of the system to 19% on average

Various characteristics of Ni and Pt–Al2O3 nanocatalysts prepared by microwave method to be applied in some petrochemical processes

AbstractAlumina-supported metal nanocatalysts were prepared via the microwave method, by loading nano Ni particles (at 1, 3 and 5wt%) or nano Pt particles (at 0.3, 0.6 and 0.9wt%). Structural and adsorption features of the nano catalysts were revealed through XRD, DSC-DTA, TEM, H2-chemisorption and N2-physisorption. N2-adsorption–desorption isotherms of type IV were related typically to mesoporous materials with H2 class of hysteresis loops characterizing ink bottle type of pores. The well dispersed nano-sized metal particles were evidenced in the studied catalytic systems, exhibiting marked thermal stability up to 800°C. The catalytic performances of different catalyst samples were assessed during cyclohexane, normal hexane and ethanol conversions, using the micro-catalytic pulse technique at different operating conditions. The 5% Ni–γ–Al2O3 sample was found to be the most active in dehydration of ethanol to produce ethylene, as well as in n-hexane cracking. However, the 1% Ni–Al2O3 sample showed the highest dehydrogenation activity for selective production of benzene from cyclohexane. On the other hand, the 0.9% Pt–γ–Al2O3 sample exhibited the highest activity in the dehydration of ethanol and in the dehydrogenation of cyclohexane. The 0.3% Pt–γ–Al2O3 sample was the most active in the dehydrocyclization of normal hexane, as compared to the other catalyst samples under study

Ants as predators of the egg parasitoid Trichogramma cacoeciae (Hymenoptera: Trichogrammatidae) applied for biological control of the olive moth, Prays oleae (Lepidoptera: Plutellidae) in Portugal

The detrimental effect of predators on Trichogramma cacoeciae March. releases to control the olive moth, Prays oleae Bern., in the Trás-os-Montes region (Northeast of Portugal), was evaluated during three releases against the flower generation of the pest in 2002. At 1 and 3 h and at 1, 3, 7 and 14 days after each release, 30 Trichogramma releasing cards were examined in the field and predators were collected and identified. Furthermore, at 1, 3, 7 and 14 days after each release, the percentage of egg predation on the cards was also determined. Formicidae were the most abundant group of predators at 99.1% of the total individuals collected. Ten species were identified, Camponotus aethiops, C. lateralis, C. piceus, C. truncatus, Crematogaster auberti, C. scutellaris, Lasius niger, Leptotorax angustulus, Plagiolephis pygmaea and Tapinoma nigerrimum. T. nigerrimum was the most abundant species, both in total numbers as well as in the number of occupied cards. One day after release, the percentage of predation was 24.0% in the first release, 59.4% in the second and 38.0% in the third. Three days after release, the percentage of predation varied from 60.2 to 83.4% during the three release events. Seven days after release, the percentage of predation increased to 97.8% of the total eggs on cards