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Biomedical subjects

B H Moon

Publications and source records attributed to B H Moon.

14 recordsLinked to original sources
PubMed2006

Effects of addition sequence and rapid mixing conditions on use of dual coagulants.

The performance of dual coagulants in clay suspension was investigated in this study using aluminium chloride and the cationic polymer as coagulants. According to the study results, the performance of dual coagulants was affected by dosage of aluminium chloride. Beneficial effect by use of dual coagulants were only noted when aluminium chloride was underdosed. The addition sequence of coagulants was important for the performance of dual coagulants. Simultaneous addition resulted in the best performance, while addition of the polymer first resulted in the worst performance. Addition of aluminium chloride first resulted in the similar performance as single use of aluminium chloride. Although sulphate ion improved the floc characteristics, similar results were obtained. The effectiveness of rapid mixing depended on dosage of aluminium chloride. Extending rapid mixing (6 min) was beneficial when aluminium chloride was underdosed so that coagulation occurred at the combination region. However, such benefit was not observed at the optimum condition, which belonged to the sweep coagulation region. Different floc formation caused the difference. Extended rapid mixing would be beneficial when collision between clay particles and Al(III) was necessary. However, such benefit would disappear at the optimum condition because rapid mixing could break up the floc already formed.

Aluminum Chloride↗
PubMed2003

Effects of salt concentration on floc characteristics and pollutants removal efficiencies in treatment of seafood wastewater by SBR.

Most seafood wastewater has been treated by the activated sludge process. Due to changes in salt concentration, pollutant loadings and raw materials, the process is not operated satisfactorily to meet effluent regulation. Most problems faced at present are solid liquid separation. In this study, effects of salt concentration on floc characteristics and pollutants removal efficiencies were investigated in treatment of seafood wastewater by SBR. For analyzing fractal dimension of flocs, the small angle laser light scattering (SALLS) method was applied using a Diffraction Particle Sizer (Malvern Instruments). Organic removal efficiencies (in terms of COD(Mn)) decreased with increasing salt concentration, but eventually reached a steady state. Fractal dimension and floc size also showed similar trends with changing salt concentration. The main reasons to reduced pollutant removal efficiencies were deteriorated biological activity and settling properties. The biological activity was affected faster than the floc characteristics by increasing salt concentration. The deteriorated settling properties were explained by decreased size and fractal dimension of floc due to increasing salt concentration. The settling properties of floc such as sludge volume index (SVI) and zone settling velocity (ZSV) were related to size and fractal dimension of floc. The fractal dimension of floc was better related to the settling properties than the size of floc.

Bioreactors↗
PubMed2003

Non-woven fabric filter separation activated sludge reactor for domestic wastewater reclamation.

A non-woven fabric filter was experimentally evaluated for solid-liquid separation in an activated sludge reactor as an alternative membrane. A polypropylene fabric filter (70, 50 and 35 g/m2) was used for the experiment. The pilot system was operated in A/O (Anaerobic/Oxic) type in which the filter module was submerged into the oxic compartment. The filtration module consists of 10 plate type rectangular filter elements with effective filtration area, 2 m2. Gravity filtration was carried out for solid-liquid separation by changing the water head 0.05-0.5 m without backwashing during the system operation. Initial permeate flux was set at 0.4 m/d. C/N ratio of raw wastewater was controlled at 4.5 in terms of BOD/T-N. The fabric filter system showed a good performance enough for domestic wastewater treatment. Effluent solid concentration was 3.2 mg/L (93.5% removal). COD removal efficiency was 91.6% producing an effluent concentration around 13 mg/L. 66% of total nitrogen removal could be obtained at the adjusted C/N ratio of influent wastewater. However phosphorus removal was very low at 23%. It was found that the initial flux of 0.4 m/d should be maintained for stable performance of the system.

Conservation of Natural Resources↗
PubMed1991

Alpha adrenergic antagonism by cyclosporine.

Cyclosporine has been shown to exert antiadrenergic actions in previous studies from this laboratory. Interactions of CsA with the alpha-one and alpha-two receptor were studied in rabbits. Blood pressure studies revealed that CsA exerts a competitive, reversible antagonism against norepinephrine, epinephrine, and phenylephrine. Further studies of heart rate depression by clonidine also demonstrated that CsA antagonizes this action. In conclusion, cyclosporine appears to act as a nonspecific alpha antagonist.

Adrenergic alpha-Antagonists↗
PubMed1989

Cyclosporine-induced hypotension.

The cardiovascular effects of i.v. infusion of cyclosporine were studied in pentobarbital-anesthetized rabbits. In doses ranging from 0.5 to 120 mg/kg/hr, CsA induced significant, sustained, dose-dependent hypotension. At the 60 mg/kg/hr dose the average drop in diastolic blood pressure was 27 mmHg (n = 9). Possible mechanisms were investigated by comparison of heart rate and blood pressure responses to physiologic manipulation, metabolic inhibition, or receptor antagonism before and after infusion of CsA. CsA did not modify responses to vagal stimulation, decreases in heart rate and blood pressure, P less than 0.001 and P less than 0.002, respectively. However, the cardiovascular reflex response during recovery was significantly attenuated after CsA infusion, P less than 0.05, n = 7. Response to bilateral carotid occlusion after CsA was decreased by 17 mmHg (n = 8, P less than 0.01). There were no significant differences between CsA alone and CsA plus glycopyrrolate or CsA plus aspirin. In this cyclosporine-induced hypotensive rabbit model, the hypotensive response appears to be related to a decrease in the endogenous sympathetic adrenergic activity, not to alterations in cholinergic tone, ganglionic transmission, or vasodilatory prostaglandin metabolism.

Adrenergic Fibers↗
PubMed1983

Morphine may not produce true catalepsy.

Though catalepsy is one of the primary features classically associated with morphine injections in animals, several investigators have suggested that morphine may not produce true catalepsy. A study was therefore undertaken using the most widely accepted tests of catalepsy to determine whether a dose related catalepsy could be obtained in rats. The effect produced by morphine was then compared with the catalepsy elicited by subthreshold to suprathreshold doses of haloperidol. In the course of catalepsy assessment, it was found that half the tests employed could not distinguish between the several doses of morphine that were administered. Moreover, the cataleptoid behavior induced by morphine failed to satisfy nearly all of the criteria most widely used for catalepsy. This is in marked contrast to the results obtained with varying doses of haloperidol. These results are compatible with the suggestion that morphine may not be a true cataleptigenic agent.

Animals↗
PubMed1979

Naloxone blockade of apomorphine-induced stereotyped behavior: interaction of endogenous opiates with dopamine.

The specific opiate antagonist, naloxone, inhibits the in vivo and in vitro activity of the endogenous opiate compounds which have heretofore been identified. In this study systemic naloxone administration successfully blocked the production of stereotyped behavior induced by the direct dopamine agonist apomorphine. This implies that the endogenous opiates contribute to the production of stereotyped behavior initiated by dopaminergic stimulation and that endogenous opiates may function as central neurotransmitters with dopaminergic activity.

Animals↗