Capture of Respirable Dust using Maintenance Free Impingement Screen

Dust produced during mining activities has a detrimental effect on both miners’ health and operations’ safety. There is no definitive treatment for coal miners’ pneumoconiosis (CWP), which is caused by prolonged inhalation of respirable dust. Elevated coal dust concentrations have also been shown to cause several disastrous explosions in the United States and worldwide, resulting in the death of miners and loss of operations. Flooded-bed dust scrubbers are used on all modern-day continuous miners. These devices cleanse the dust-laden air and assist in bringing fresh air towards the mining face. Scrubbers use a multi-layered fibrous screen to capture airborne particles. These systems direct the dust-laden air towards the fibrous screen mounted upstream of a water spray. These screens capture dust on the finely woven surface. Prolonged scrubber operations lead to dust accumulation, which can result in filter clogging. This increases the pressure-drop across the screen and causes a lowered airflow through the scrubber. Reduced capture efficiency of the scrubber may lead to an enhanced exposure of the miners nearby. This thesis presents the design of three full-scale non-clogging, maintenance-free impingement type screens. The findings of Computational Fluid Dynamics (CFD) modeling, laboratory studies using coal, and rock (limestone) dust to determine cleaning efficiency are presented. In-mine tests were conducted to examine the performance of each screen using limestone dust as an aerosol. The newly designed impingement screens outperform the conventional fibrous screen at all airflows between 4,000 and 8,000; therefore, they may be a potential replacement for the fibrous screen

Evaluation of the effect of three innovative recyling methods on the shear bond strength of stainless steel brackets-an in vitro study

Orthodontists are commonly faced with the decision of what to do with debonded or inaccurately positioned brackets. An economical option to this dilemma is to recycle the brackets. Many recycling methods have been proposed, but the optimal bond strength of these recycled brackets needs further evaluation. Objectives: To evaluate and compare the effect of three recycling methods: (i) Sandblasting (ii) Sandblasting / direct flaming (iii) Sandblasting /direct flaming /acid bath solution on shear bond strength (SBS) of stainless steel brackets. Eighty human premolars were bonded with premolar stainless steel brackets as per manufacturer?s instructions. The teeth were divided into 4 groups (n=20): Recycling and initial debonding was not done in Control group (Group I). After initial bonding, the brackets in the rest of the three experimental groups were debonded and recycled by following methods: (i) Sandblasting (Group II) (ii) Sandblasting /direct flaming (Group III) (iii) Sandblasting /direct flaming /acid bath solution (Group IV). Further the recycled brackets were bonded. The specimens were then subjected to testing in a Universal machine. The evaluation of the variation of the shear bond strength (SBS) among test groups was done using one-way ANOVA test and inter-experimental group comparison was done by Newman-Keuls multiple post hoc procedure. Group I (8.6510±1.3943MPa) showed the highest bond strength followed by Group II (5.0185±0.9758MPa), Group IV (2.30±0.65MPa) and Group III (2.0455± 0.6196MPa). Statistically significant variations existed in the shear bond strength (SBS) in all groups analyzed except between Group III and Group IV. The following conclusions were drawn from the study: 1. Shear bond strength of new brackets is significantly higher than the recycled brackets. 2. Brackets sandblasted with 90µm aluminium oxide particle air-abrasion showed significantly higher shear bond strength compared to direct flaming/sandblasting and direct flaming/sandblasting/acid bath solution. 3. Sandblasting with 90µm aluminium oxide particle air-abrasion is the simplest, most efficient and hence, the preferred method of recycling debonded brackets

Stem Cell Antigen CD34 In Native And Engineered Form Alter Its Binding Ability To Stromal Cells And Ligands: A Classical Example Of Clinical Benefits Of Therapeutic Genetic Engineering Of Stem Cells In Transplantation

CD34 is a highly glycosylated surface-expressed sialomucin and, because it is present on hematopoietic stem cells (HSCs), has demonstrated immense clinical utility in their enumeration in aphaeresis products, immunoaffinity purification for transplantation, and disease monitoring. The success of CD34 based reagents in identifying hematopoietic progenitors led to the assumption that CD34 is expressed on cells with regenerative potential and is sufficient for hematopoietic reconstitution in marrow-ablated recipients. However, its role has not been identified in substantial detail. 

With the advent of the fact that CD34 binds adapter protein like CRK-L in cytosol and CD34 knock out studies identified a a signaling role, CD34 antigen has been proposed to play a signaling function. Since it is a sialomucin, a member of the group adhesion molecules, we attempted to identify a role by over-expreesing its gene in cell lines. We report here that CD34 and engineered forms (Ser306 & Tyr318) significantly regulates adhesion to stromal cells, like mesenchymal stem cells and bone marrow ligands. These enhance binding of cells overexpressing CD34 by upregulating integrins and we therefore propose that such cells may effectively potentiate the success of transplantation through greater homing if they are used for transfusion

Laboratory Determination of Coal Dust Cleaning Efficacy of a Fibrous Filter for Flooded-Bed Dust Scrubber

Fibrous-type dust filters are used in flooded-bed dust scrubbers to capture dust from underground room and pillar mining atmospheres. They have 10–30 layers of finely woven strands that trap particles through the interception and impaction process. A full-cone water spray is installed upstream of the filter, which floods the screen. A scrubber’s efficacy is usually measured and reported in terms of reduction in gravimetric dust concentration at a known location in a mine. This paper reports the particle-size-dependent dust removal efficiency of a fibrous filter obtained from an instrumented test-set up. A variable frequency drive and an inline flow control knob were used to control the airflow through the filter and water flow onto the filter. Optical particle counting of coal dust particles upstream and downstream was carried out to determine the cleaning efficacy. Experiments showed an increase in cleaning efficiency for all the dust particles with their size. A progressive decrease in dust concentration downstream of the filter with an increase in water flow through the nozzle affirmed the capture of dust particles by water sprays

SYNTHESIS AND ANTIMICROBIAL ACTIVITY EVALUATION OF SOME SCHIFF BASES DERIVED FROM 2-AMINOTHIAZOLE DERIVATIVES

Various substituted acetophenones (1-5) on treatment with iodine and thiourea yielded 2-amino-4-(substituted-phenyl)-thiazole (1a-5a), which on further treatment with various substituted aldehydes to get N-(substitutedbenzylidene)-4-(substitutedphenyl) thiazol-2-amine (1b-5b). All the synthesized compounds were characterized by their respective FTIR, 1H NMR and mass data. Synthesized compounds (1b-5b) were subjected to investigation for their antibacterial and antifungal studies against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, Asperigillus flavus and Asperigillus fumigatus by disk diffusion method. Compound 5b was found to be most effective with largest zone of inhibition.Key words: thiazole, acetophenones, antibacterial, antifungal, substituted aldehydes

Comparison of dietary agents’ garlic and bitter melon on in vitro glycation and advanced glycation end products formation

Background: Protein glycation is a spontaneous post translational modification of proteins by excess sugars causing formation of advanced glycation end products (AGEs) in diabetic individuals and responsible for diabetes complications. Momordica charantia L (bitter melon) and garlic have been used historically for medicinal purposes particularly for treatment of diabetes and cancers and contain potent antioxidant activity hence we planned to compare the antiglycating activities.Methods: Human serum albumin (HSA) was used for in vitro glycation. Various concentrations of extracts of M. charantia L and aged garlic were analyzed.Results: Co-incubation of the M. charantia L and aged garlic extracts with HSA-fructose mixture gives contradictory results in tryptophan fluorescence, AGE specific fluorescence and protein bound carbonyl studies.Conclusions: M. charantia L seems to aggravate sugar mediated glycation of the protein and need further studies to pinpoint specific bioactive compounds responsible for the observed activities whereas aged garlic seems to have strong ant glycation properties