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Does chemomechanical caries removal affect restoration survival?Stolic, Nicole January 2015 (has links)
SyfteDenna systematiska översiktsstudie gjordes i syfte att sammanställa randomiserade kontrollerade studier som jämför fyllningsöverlevnaden där kaviteten preparerats med Carisolv, borr och/eller hand exkavering. Studien gjordes också för att kunna användas till fortsatta studier inom området.Material & MetodDatabassökning i PubMed och Cochrane gjordes. Alla titlar och sammanfattningar lästes, de som var relevanta för denna studie lästes sedan i fulltext. Totalt 9 artiklar inkluderades och varje artikel granskades m h a GRADE modellen för att bestämma studiernas evidensstyrka.Resultat913 tänder behandlades med en av metoderna. Studierna undersökte fyllningsöverlevnaden vid olika uppföljningstillfällen, mellan 6 månader och 2 år. Resultaten visar inga statistiskt signifikanta skillnader för fyllningsöverlevnad mellan de olika metoderna.SlutsatsResultaten visar ingen statistisk skillnad i fyllningsöverlevnad mellan Carisolv och andra metoder för att avlägsna karies. Resultaten kan stödja karies exkavering med Carisolv, eftersom metoden dessutom kan användas för karies exkavering på barn och tandvårdsrädda patienter då metoden är mindre obehaglig och patienten behöver således inte lokalanestesi lika ofta. Dock är studierna inom detta område få samt att de har låg evidensstyrka vilket gör att det behövs fler studier på området med högre evidensstyrka. / AimThis systematic review aimed to summarize randomized controlled trials (RCTs) that evaluate the survival rates of restorations, comparing the Carisolv system to hand excavation and/or the conventional drilling method. The aim was also to collect all data in one place to be used for further research.Materials & MethodsA database screening of PubMed and the Cochrane library was performed. One reviewer read all titles and abstracts, those considered of interest were fully scrutinized. A total of 9 articles were included and each was evaluated using the GRADE-system. The studies were appraised to have a low level of evidence.ResultsA total 913 teeth received treatment either with Carisolv, hand excavation and/or drilling. The studies evaluated the success rate of dental restorations at follow-ups between 6 months to two years. The results showed no significant difference in success rate of restorations made either by Carisolv, bur or hand excavation.ConclusionsThe results showed as high success rates for caries removal with Carisolv as with other methods, in terms of restoration survival, and that there was no statistically significant difference between the test group and control group. These results are encouraging for caries removal with Carisolv since it also can be used as an alternative treatment for children and patients with dental fear due to the less painful experience and lesser need for local anesthesia. The present studies on this subject are few and have limited evidence, thus underlining the need for more studies on the subject and studies with higher evidence for further research.
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“HERE THEY ARE IN THE LOWEST STATE OF SOCIAL GRADATION —ALIENS—POLITICAL—MORAL—SOCIAL ALIENS, STRANGERS, THOUGH NATIVES”: REMOVAL AND COLONIZATION IN THE OLD NORTHWEST, 1815-1870Davis, Samuel January 2019 (has links)
This dissertation examines African colonization and Native removal colonization schemes and their relationship to the development of states carved out of the Northwest Territory. Colonization advocates sought to expunge the nation of slavery, free blacks, and native peoples to make a white republic. This research contends that colonization promoted racial nationalism by campaigning for a safe and homogenous nation free of slavery, ‘degraded’ free blacks, and dangerous Native Americans. It explores the execution and afterlives of American projects for African colonization, through the American Colonization Society, and Native Removal in the Old Northwest. It examines the rhetoric and procedures related to the colonization of Native Americans in the West and free blacks to Liberia in which government officials, journalists, settlers, businessmen, missionaries, and clergy in Ohio, Indiana, and Illinois traded in fears of racial degradation and national security as a means to generate fiscal support and positive public opinion for legislation and policies that attempted to create a white republic. Colonizationists appropriated imperial relocation solutions to the domestic problems of black freedom and Native sovereignty that they construed as prohibitory to national expansion and development. Ventures to deport Native Americans and African Americans successfully constructed them as dangerous aliens within the nation that validated their exclusion. In their resistance African Americans, Native Americans, and their allies adapted, fled, petitioned, ridiculed, and negotiated with colonizationist endeavors to maintain residence in the Midwest. The fictions of colonization, driven by its rhetoric, required new constructions about black and Native degradation to justify the calls for their removal. / History
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The Effect of Sex-Accessory Gland Removal on Strange-Male-Induced Pregnancy Disruptions in MiceZacharias, Rosemary 08 1900 (has links)
<p> Early pregnancy in mammals can be disrupted by numerous stimuli. In particular, exposure to males which did not sire the litter disrupts early pregnancy in previously inseminated female mice. This is known as the Bruce effect. Evidence suggests that this effect is mediated by chemical emissions (pheromones) from the males. Castration of the males eliminates the effect whereas testosterone replacement restores it. This has suggested that
androgen-dependent male accessory glands might be responsible. In particular, the preputial, vesicular and coagulating glands seem likely candidates for subserving the Bruce effect since they have been implicated in a variety of social behaviors.</p> <p> In these experiments, inseminated females were each housed below either 1) two males which had undergone preputial gland removal or, 2) two males which had undergone vesicular-coagulating gland removal or, 3) two males which had undergone preputial, vesicular and coagulating gland removal or 4) two males which had undergone sham surgery. In each case, males which had undergone gland removal disrupted pregnancy in inseminated females to the same extent as did intact males. Histology showed no regeneration of the glands. These results suggest that none of these major androgen-dependent male accessory glands is responsible for pheromonal emissions involved in the Bruce effect.</p> / Thesis / Master of Science (MSc)
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Towards optimizing the operation of microbial electrolysis cells for heavy metal removalFuller, Erin January 2018 (has links)
Heavy metals are a growing environmental concern as they are unable to be
metabolized in the environment, leading to bioaccumulation in the food chain and
impacting human health. Treating heavy metals is difficult and expensive. Current
methods include precipitation (which generates sludge that is costly to dispose of) or
requires the use of a membrane, which fouls and requires regeneration.
Microbial electrolysis cells (MECs) represent an alternative for treating heavy
metal contaminated wastewater. Reactor components are cheap, and operation requires
only a small amount of electricity. The electrically active biofilm oxidizes organics in the
wastewater while transferring electrons first to the anode, then to the cathode, where
aqueous metals are reduced to a solid deposit, a mechanism called electrodeposition. Few
studies have been conducted to investigate the best operational conditions for heavy
metal removal in MECs. In this study, the effects of hydrodynamics, applied voltage, and
initial metal concentration on heavy metal removal mechanisms are investigated, and the
best operational practices are determined on a high level.
Mixing in the cathode chamber increased electrodeposition by 15%, decreased the
cathode potential by -0.06 V, and increased current generation between 10-30%.
Increasing the applied voltage from 0.6 V to 1.2 V increased electrodeposition by 22%.
With both mixing and higher voltage applied, 93.35% of cadmium was removed from the
catholyte in 24 hours. Although high voltage application maximized electrodeposition for
short-term treatment, long-term treatment indicated lower applied voltage resulted in
healthier MEC reactors, better overall metal recoveries, along with a more stable cathode
potential. / Thesis / Master of Applied Science (MASc)
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Significant energy savings by optimising membrane design in multi-stage reverse osmosis wastewater treatment processAl-Obaidi, Mudhar A.A.R., Kara-Zaitri, Chakib, Mujtaba, Iqbal M. 18 January 2018 (has links)
Yes / The total energy consumption of many Reverse Osmosis (RO) plants has continuously improved as a result of manufacturing highly impermeable membranes in addition to implementing energy recovery devices. The total energy consumption of the RO process contributes significantly to the total cost of water treatment. Therefore any way of keeping the energy consumption to a minimum is highly desirable but continues to be a real challenge in practice. Potential areas to explore for achieving this include the possibility of optimising the module design parameters and/or the associated operating parameters. This research focuses on this precise aim by evaluating the impact of the design characteristics of membrane length, width, and feed channel height on the total energy consumption for two selected pilot-plant RO process configurations for the removal of chlorophenol from wastewater. The proposed two configurations, with and without an energy recovery device (ERD), consist of four cylindrical pressure vessels connected in series and stuffed with spiral wound membranes. A detailed steady-state model developed earlier by the authors is used here to study such impact via repetitive simulation. The results achieved confirm that the overall energy consumption can be reduced by actually increasing the membrane width with a simultaneous reduction of membrane length at constant membrane area and module volume. Energy savings of more than 60% and 54% have been achieved for the two configurations with and without ERD respectively using process optimization. The energy savings are significantly higher compared to other available similar studies from the literature.
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Ethanol amine functionalized electrospun nanofibers membrane for the treatment of dyes polluted wastewaterAlAbduljabbar, Fahad A., Haider, S., Alghyamah, A., Haider, A., Khan, R., Almasry, W.A., Patel, Rajnikant, Mujtaba, Iqbal M., Ali, F.A.A. 25 March 2022 (has links)
Yes / This study investigated adsorption kinetics, adsorption equilibrium, and adsorption isotherm of three dyes [i.e., methylene blue (MB), rhodamine-B (RB), and safranin T (ST)] onto polyacrylonitrile (PAN) and ethanolamine (EA) grafted PAN nanofibers (NFs) membranes (EA-g-PAN). The membranes were characterized by field emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FT-IR) spectroscopy, and Brunauer–Emmet–Teller (BET). FE-SEM showed a smooth morphology for the NFs before and after grafting, while FT-IR confirmed EA grafting into the nitrile group of PAN. The grafting percentage with no change in the physical nature of the membrane was 12.18%. The nitrogen adsorption–desorption isotherms for PAN and EA-g-PAN NFs membranes were similar and classified as a Type IV according to the International Union of Pure and Applied Chemistry. The surface area, pore-volume, and pore size of the EA-g-PAN increased to 21.36 m2 g−1, 0.16 cm3 g−1, and 304.93 Å, respectively. The pores were cylindrical mesopores with bimodal openings, which means that pores were open at both ends. The adsorption of the MB, RB, and ST dyes onto the PAN and EA-g-PAN NFs membranes leveled off at ~ 60 min. The adsorption kinetics showed good fitting to pseudo-second-order kinetic model and multi-step diffusion process. The order of the dye adsorption was PAN / the Deanship of Scientific Research, King Saud University [RG-1440-060]
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Response surface methodology for predicting the dimethylphenol removal from wastewater via reverse osmosis processAl-Obaidi, Mudhar A.A.R., Al-Nedawe, B., Mohammad, A., Mujtaba, Iqbal M. 31 March 2022 (has links)
Yes / Reverse Osmosis (RO) process can be considered as one of the intensively used pioneering equipment for reusing wastewater of several applications. The recent study presented the development of an accurate model for predicting the dimethylphenol removal from wastewater via RO process. The Response Surface Methodology (RSM) was applied to carry out this challenge based on actual experimental data collected from the literature. The independent variables considered are the inlet pressure (5.83-13.58) atm, inlet temperature (29.5-32) ° C, inlet feed flow rate (2.166-2.583) × 10-4 m3/s, and inlet concentration (0.854-8.049) × 10-3 kmol/m3 and the dimethylphenol removal is considered as the response variable. The analysis of variance showed that the inlet temperature and feed flow rate have a negative influence on dimethylphenol removal from wastewater while the inlet pressure and concentration show a positive influence. In this regard, F-value of 240.38 indicates a considerable contribution of the predicted variables of pressure and concentration against the process dimethylphenol rejection. Also, the predicted R2 value of 0.9772 shows the high accuracy of the model. An overall assessment of simulating the performance of RO process against the operating parameters has been systematically demonstrated using the proposed RSM model.
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Chemical and Biological Treatment of Acid Mine Drainage for the Removal of Heavy Metals and AcidityDiz, Harry Richard 16 September 1997 (has links)
This dissertation reports the design of a process (patent pending) to remove iron from acid mine drainage (AMD) without the formation of metal hydroxide sludge. The system includes the oxidation of ferrous iron in a packed bed bioreactor, the precipitation of iron within a fluidized bed, the removal of manganese and heavy metals (Cu, Ni, Zn) in a trickling filter at high (>9) pH, with final neutralization in a carbonate bed. The technique avoided the generation of iron oxyhydroxide sludge.
In the packed bed bioreactor, maximum substrate oxidation rate (R<sub>,max</sub>) was 1500 mg L⁻¹ h⁻¹ at dilution rates of 2 h⁻¹, with oxidation efficiency at 98%. The half-saturation constant (similar to a Ks) was 6 mg L⁻¹. The oxidation rate was affected by dissolved oxygen below 2 mg L⁻¹, with a Monod-type Ko for DO of 0.33 mg L⁻¹. Temperature had a significant effect on oxidation rate, but pH (2.0 to 3.25) and supplemental CO₂ did not affect oxidation rates.
Iron hydroxide precipitation was not instantaneous when base was added at a OH/Fe ratio of less than 3. Induction time was found to be a function of pH, sulfate concentration and iron concentration, with a multiple R² of 0.84. Aqueous [Al (III)] and [Mn (II)] did not significantly (α = 0.05) affect induction time over the range of concentrations investigated.
When specific loading to the fluidized bed reactor exceeded 0.20 mg Fe m⁻² h⁻¹, dispersed iron particulates formed leading to a turbid effluent. Reactor pH determined the minimum iron concentration in the effluent, with an optimal at pH 3.5. Total iron removals of 98% were achieved in the fluidized bed with effluent [Fe] below 10 mg L⁻¹. Further iron removal occurred within the calcium carbonate bed.
Heavy metals were removed both in the fluidized bed reactor as well as in the trickling filter. Oxidation at pH >9 caused manganese to precipitate (96% removal); removals of copper, nickel, and zinc were due primarily to sorption onto oxide surfaces. Removals averaged 97% for copper, 70% for nickel and 94% for zinc.
The treatment strategy produced an effluent relatively free of iron (< 3 mg/L), without the formation of iron sludge and may be suitable for AMD seeps, drainage from acidic tailings ponds, active mine effluent, and acidic iron-rich industrial wastewater. / Ph. D.
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The reduction of high nitrate-nitrogen concentrations in natural watersThacker, Henry Ray January 1964 (has links)
Ph. D.
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Characterizing Kinetic Shifts in Nitrifying, Denitrifying, and Phosphorus Removing Biomass Adapting to Low DOKisling, Tyler Houston 03 November 2022 (has links)
Low dissolved oxygen (DO) biological nutrient removal (BNR) is becoming a viable option to improve the energy efficiency of BNR. To properly model and design BNR processes for low DO operation, it is critical to fully understand how nitrifier, denitrifier, and polyphosphate accumulating organism (PAO) oxygen kinetics adapt in a shift from traditional DO operation (2 mg O2/L or more) to low DO operation. Research characterizing how oxygen kinetics shift over time in activated sludge biomass adapting to low DO is limited. Therefore, a method to characterize oxygen kinetics for nitrifiers, denitrifiers, and PAOs simultaneously is lacking. Here a method was developed to simultaneously measure the oxygen kinetics of nitrifiers, denitrifiers, and PAOs. This method, termed the SND and P-Uptake Oxygen Kinetics test, was able to estimate the ammonia oxidizing bacteria (AOB) oxygen half-saturation coefficient, ammonia maximum removal rate, denitrifier oxygen inhibition coefficient, total inorganic nitrogen (TIN) maximum removal rate, PAO oxygen half-saturation coefficient, phosphorus maximum uptake rate, and a simultaneous nitrification and denitrification (SND) optimum operation point. Three tests were conducted on the Virginia Initiative Plant (VIP) BNR Activated Sludge Pilot while it was operating at a process DO of 2 mg O2/L, and one test while it was operating at 1.5 mg O2/L. The measurements among the three initial tests showed high similarity in their parameter estimates. Estimated oxygen half-saturation and oxygen inhibition coefficients were compared to current suggested ranges and were within the expected magnitudes. At 2 mg O2/L, denitrifier oxygen inhibition coefficients and PAO oxygen half-saturation coefficients were estimated to be remarkably low here, under 0.4 and 0.1 mg O2/L, respectively. AOB oxygen half-saturation coefficients were variable here in the range of 0.62 to 2.57 mg O2/L, seeming to vary with available ammonia concentrations. Upon comparison with a previously developed respirometric test for nitrifier oxygen kinetics, termed the Declining DO test, the AOB oxygen half-saturation coefficient from the SND and P-Uptake Oxygen Kinetics test and the Declining DO test, when both were conducted on the VIP BNR Pilot, showed a similar trend. This provided validation for the AOB oxygen kinetics here and the usefulness of the test developed here. Additionally, measuring and plotting AOB and denitrifier oxygen kinetics together produced an intersection point where ammonia removal rates were equal to TIN removal rates. This intersection point was an optimum point for SND during the conditions of the test. This method can be used to characterize and track oxygen kinetic changes in a BNR system adapting from high to low DO. / Master of Science / Aerating biological processes in wastewater treatment plants is necessary to facilitate nitrogen and phosphorus removal but is extremely costly. Traditional dissolved oxygen concentrations in these processes are 2 mg O2/L or higher. Operating processes with low dissolved oxygen (DO) concentrations, less than 1 mg O2/L, can cut costs significantly. However, designing processes at low DO concentrations requires knowledge of how microorganisms utilize substrate with lower oxygen availability and how substrate utilization develops when gradually decreasing the DO concentration in a process. Here, a method was developed to measure the parameters describing the relationship between substrate utilization and DO concentration for the microorganisms responsible for nitrogen removal (nitrifiers and denitrifiers) and phosphorous removal (polyphosphate accumulating organisms). Additionally, the method provides an optimum DO setpoint for simultaneous nitrification and denitrification (SND) during testing conditions. This method, termed the SND and P-Uptake Oxygen Kinetics test, was able to estimate the following parameters simultaneously: ammonia oxidizing bacteria (AOB) oxygen half-saturation coefficient, ammonia maximum removal rate, denitrifier oxygen inhibition coefficient, total inorganic nitrogen (TIN) maximum removal rate, PAO oxygen half-saturation coefficient, and phosphorus maximum removal rate. Three tests were conducted on the Virginia Initiative Plant (VIP) BNR Activated Sludge Pilot while it was operating at a process DO of 2 mg O2/L, and one test while it was operating at 1.5 mg O2/L. The measurements among the three initial tests showed high similarity in their parameter estimates. Estimated oxygen half-saturation and oxygen inhibitions coefficients were compared to current suggested ranges and were within the expected magnitudes. Upon comparison with a previously developed test for nitrifier oxygen kinetics, termed the Declining DO test, the AOB oxygen half-saturation coefficient from the SND and P-Uptake Oxygen Kinetics test and the Declining DO test when both were conducted on the VIP BNR Pilot showed a similar trend, providing validation for the usefulness of the test developed here.
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