Influence of the type of viscosity-modifying admixtures and metakaolin on the rheology of grouts

The Viscosity-modifying admixtures (VMAs) contribute to the control of the rheology of grouts and are used to enhance plastic viscosity, cohesion, stability, and resistance to bleeding of cement-based systems.  This paper reports the results of an investigation on the effect of type of VMAs, namely two types of diutan gums and a welan gum and metakaolin (MTK), plus a superplasticiser, on the rheology behaviour of cement grouts.  All mixes were made with polycarboxylic superplasticiser at 0.6% and 0.9%.  The dosages of VMAs were 0.05%, and 0.10%, with a fixed water-to-binder ratio of 0.40.  The investigated fresh properties of the grouts included the mini-slump flow, plate cohesion, and rheology parameters: namely yield value and plastic viscosity.  The rheological parameters were obtained using a vane viscometer.  Control grouts (with and without superplasticiser and VMA) were also tested and compared to mixes containing VMAs.  The results indicated that the incorporation of MTK reduced the fluidity and increased the plate cohesion and yield stress, and plastic viscosity due to the higher surface area of MTK.  The diutan gum grouts improved the grout fresh properties and rheology compared to the welan gum grouts

Effect of high fat and nutrient depleted diets on colon tumor formation in mice.

We investigated the effect of high fat and nutrient depleted diets on the formation of colon tumors in female Swiss mice treated with 1,2- dimethylhydrazine (DMH). Mice received the following diets: control diet (laboratory chow, 5.5% fat) or chow with added starch and/or corn oil so as to supply a fat level of 5.5% (diet F6) or 23% (diet F23), while reducing the level of nutrients and dietary fiber per. 100 calories to 61% of the level of the control diet. DMH was given as 5 weekly s.c. injections. Diets were given variously from 6 weeks before the first injection until 7 days after the last one (initiation period) or else for the subsequent 22 weeks until sacrifice of the mice (promotion period). A high fat diet (diet F23 vs. F6) tended to increase adenoma formation when fed during the initiation period but this requires further study. Feeding it in the promotion period increased the incidence of adenocarcinomas. A nutrient depleted diet (diet F6 vs. the control diet) caused a decreased incidence of adenocarcinomas

Changes in pH and levels of B-glucosidase, B-glucuronidase and reducing activity as food residue passes along the mouse colon

The contents were collected from successive regions of the colon of Swiss mice. Ana(vses show that the pH rises by about 0.55 pH units between the cecum and the distal colon. The level of p-glucuronidase falls sharply, typically 2 to 3 fold;, as food residue leaves the cecum. This is followed by a large rise in the distal c%n, mvund 1.6 to 4 fold, about half of 1vhich is due to the concentrating ejlect caused by loss of water. lvleasurements were also made of nonspecific reducing activity, the level of which rises by about 74% along the colon mainly because of water loss. For each of the above parameters similar results were observed using old and young mice and with diets high and low in fat. Studies indicated that the reducing activity is nonenzymic

Toxicity of 1,2-dimethlyhydrazine in mice: effect of diet and development of tolerance

The effect of diet on the lethality of 1, 2-dimethylhydrazine (DMH) injections was investigated using Swiss mice. Mortality was highest when mice were fed a nutrient-dilutealfhigh-fat diet, was intermediate with a nutrientdilutealflow- fat diet and was lowest with laboratory chow. Wheat bran was not protective. Mice developed tolerance to DMH after receiving several injections of progressively increasing dose

Cabbage and vitamin E: their effect on colon tumor formation in mice.

The effects of cabbage and vitamin E on colon carcinogenesis were investigated in Swiss mice treated with 1,2-dimethylhydrazine. Throughout the experiment the mice were fed a laboratory chow diet (46 mg vitamin E per kg) or chow containing 13 g cabbage per 100 g or 180 mg vitamin E per kg. Starting after 31 days of diet treatment the mice received 7 weekly s.c. injections of DMH. They were sacrificed 17 weeks after the first dose of DMH. While diet did not significantly alter colon tumor response, some trends were observed. Female mice given cabbage had a higher incidence. (percent of mice with a tumor) and multiplicity (tumors per tumor bearing mouse) of colon tumors. Males were little affected by cabbage apart from a lower incidence of adenocarcinomas. Compared with mice fed the control diet those given vitamin E had a higher colon tumor incidence, This effect, which was stronger in females, was due to an increased incidence of adenomas. Vitamin E had little apparent affect on tumor multiplicity apart from a reduction in adenocarcinomas in females and adenomas in males. The data do not support the view that cabbage and vitamin E are protective against colon cancer

High-Fat Diets and Fecal Level of Reductase and Colon Mucosal Level of Ornithine Decarboxylase, B-Glucuronidase, 5'-Nucleotidase, ATPase, and Esterase in Mice.

In one experiment Swiss mice were maintained on a 16 or 23% fat diet (laboratory chow with added fat, principally corn on) or on laboratory chow alone (5.5% fat), In another experiment CS7BU1 mice were given a 23% fat diet (as above) or a low-fat diet (67% laboratory chow. 1.9% corn oil, and 31% starch; 5.5% fat). Colon mucosal samples were analyzed for several enzyme activities. In Swiss mice the analyses revealed the following: 1) Ouabain-insensitive ATPase was unaltered in male mice, but it rose significantly in females fed a high-fat diet (this effect was seen when a resuspended high-speed pellet was analyzed but not seen with the initial homogenate); 2) S'-nucleotidase activity showed a significant stepwise increase with dietary fat; 3) nonspecific esterase activity tended to rise with a high-fat diet (not significant); 4) fJ-glucuronidase levels were not altered by diet fat; and 5) ornithine decarboxylase levels were not altered by diet fat. In CS7BU1 mice analyse:;, were done on ouabaininsensitive ATPase, S'-nucleotidase, nonspecific esterase, and p-glucuronidase, but no diet effects were seen. Fecal reductase activity was measured with the use of 2-(p-iodophenyl)-3-(pnitrophenyl)- 5-phenyltetrazolium chloride hydrate). A high-fat diet did not affect the activity in CS7BU1 mice, but it caused a significant rise in Swiss mice

Double precision trajectory program /DPTRAJ 2.2C/

Four part program computes trajectory of space probe moving in solar system and subject to variety of forces

Solving the Direction Field for Discrete Agent Motion

Models for pedestrian dynamics are often based on microscopic approaches allowing for individual agent navigation. To reach a given destination, the agent has to consider environmental obstacles. We propose a direction field calculated on a regular grid with a Moore neighborhood, where obstacles are represented by occupied cells. Our developed algorithm exactly reproduces the shortest path with regard to the Euclidean metric.Comment: 8 pages, 4 figure

INVESTIGATION OF ALUMINUM TOXICITY AMONG WORKERS IN ALUMINUM INDUSTRY SECTOR

The study was conducted to evaluate urine aluminum concentration among a total of 150 participants (80 aluminum technicians and 70 non- aluminum technicians as a control). Data were collected through a previously prepared questionnaire which consists of two parts. The first part concerned with demographic data such as age and nationality. The second part concerned with occupational data such as working hours, working years, smoking, and diseases. The mean concentration of aluminum is 51.62+ 29.59 μg/l and the mean concentration of group control 16.32 + 12.49 μg/l. The following variables were associated significantly with aluminum concentration: age, weekly working hours, smoking and daily smoking packets.According to our study, aluminum workers have high concentrations of urine aluminum compared with other studies, in addition to that the incidence of diseases in relation to exposure is low, simply because: 1-Self reported questionnaires may be not a proper way to collect data about diseases. 2- Traditional surveillance approaches used in public health practice are difficult to apply to metals poisoning because adverse health effects related to metal exposure may not be clinically diagnosed, except at very high exposure levels, and are not usually listed as reportable diseases.Finally Special safety precautions and educational programs are also needed to limit the aluminum exposure in this industrial group