Effect Of Various Positions Research Articles

Biomimetic approach to strengthen the incisal fracture composite build-up: an in vitro study

ObjectiveIncisal composite build-up shows a high failure susceptibility. The incorporation of fiber-reinforced composite (FRC) during composite restoration could improve its strength. Hence the study was planned to compare the effect of various positions of FRC on the strength of composite resin incisal build-ups.MethodsIn maxillary incisors (n = 90), 3 mm of the incisal edge was cut and teeth were categorized into three groups based on the location and number of fibers used during incisal composite build-up - Group I: composite resin; Group II: composite resin and a single fiber palatally and Group III: composite resin along with two fibers palatally.ResultsThe data showed that group II had the maximum load-bearing values followed by group I and group III.ConclusionWithin the confines of our study, it can be concluded that the addition of FRC to the conventional incisal composite build-up increased the overall strength restoration. Such composite restoration reinforced with a single fiber on the palatal side showed the highest load-bearing capacity compared to two fibers reinforced and unreinforced composites. The common mode of failure in group I was in composite resin, in two fibers reinforced at fibers-composite junction, and in one fiber reinforced composite was in the remaining part of the tooth.

Numerical Study the Effect of Cylinder Location on the Mixed Convection in an Open Square Cavity

Mixed convection heat transfer of air in a horizontal channel with an open square cavity is studied numerically. At the center of the cavity, it is an insulated rotating circular cylinder for enhancing the efficiency of heat transmission, the location of the inner cylinder is changed vertically along the centerline of the cavity. Heat is applied to the bottom wall of the cavity at a constant temperature, and the other walls are adiabatic. The flow is steady-state, laminar, and incompressible. Using computational fluid dynamics (CFD) and the commercial software program FLUENT 2019 R1, the equations of continuity, momentum, and energy are numerically solved. The angular velocity of the cylinder range is (0.5 ≤ ω ≤ 4) rad/sec in a counterclockwise direction, the Richardson number range (Ri = 0.1,1, 10), Reynolds number is 100 and the cylinder location is (C = 70,50,30) mm. The airflow Prandtl number is taken as (Pr = 0.7). The effect of various positions of the rotating cylinder has been examined through the visualization of streamline and isotherm contour, as well as the distribution of the average Nusselt number of the heated surface. The results indicate that the flow field and temperature distributions inside the cavity are strongly dependent on the rotating circular cylinder and the position of the inner cylinder.

Propellant Mass Gauging in a Spherical Tank under Micro-Gravity Conditions Using Capacitance Plate Arrays and Machine Learning.

Propellant mass gauging under micro-gravity conditions is a challenging task due to the unpredictable position and shape of the fuel body inside the tank. Micro-gravity conditions are common for orbiting satellites and rockets that operate on limited fuel supplies. Capacitance sensors have been investigated for this task in recent years; however, the effect of various positions and shapes of the fuel body is not analyzed in detail. In this paper, we investigate this with various fill types, such as annular, core-annular, and stratified fills at different positions. We compare the performance among several curve-fitting-based approaches and a machine-learning-based approach, the latter of which offers superior performance in estimating the fuel content.

Effect of Different Positions on Arterial Oxygen Saturation during Enteral Feeding of Preterm Infants Admitted to Neonatal Intensive Care Units

Background: This study aimed to determine the effects of various positions on the arterial oxygen saturation during enteral feeding of preterm infants admitted to Neonatal Intensive Care Units (NICUs). It is assumed that different body positions influence arterial oxygen saturation during enteral feeding.Methods: This crossover clinical trial included 88 infants. The inclusion criteria were gestation age of fewer than 32 weeks, a weight of 1001-1500 gr, age of fewer than one month, 5-minute Apgar score of at least 5, exclusive breast-feeding, absence of any underlying illness, no oxygen therapy, and a minimum feed volume of 10cc for two h. The subjects were selected from the infants admitted to NICUs at Alzahra, Shahid Beheshti, and Amin hospitals, Isfahan, Iran, using a convenience sampling method. Subsequently, they were randomly assigned to four groups of 22 cases per group. The four groups were A, B, C, and D who were initially positioned on the left side, supine, prone, and right side, respectively. The arterial oxygen saturation was recorded on a minute-by-minute basis 5 min before, during, and 5 min after enteral feeding. Data were analyzed in STATA software (version 14) using a one-way analysis of variance, (ANOVA), linear mixed model, and the Chi-square test.Results: According to the results of the one-way ANOVA and Chi-square test, no significant difference was observed among the four groups regarding the demographic characteristics. Moreover, the linear mixed model revealed no significant difference among the four groups of intervention, the four periods of the study, and carryover effect in terms of the mean oxygen saturation before, during, and after enteral feeding.Conclusion: The results revealed that variations in infant positions during feeding had no effects on the arterial oxygen saturation. Therefore, neonatal nurses are advised to carry out enteral feeding without unnecessary changing of the infant position, which leads to lower manipulation, and improved sleep and awakening cycle of the infants.

The effect of the pelvis position in the sagittal plane on loads in the human musculoskeletal system

The research work aimed to perform the mathematical modelling-based assessment concerning the effect of the position of the pelvis in the sagittal plane on loads present in the musculoskeletal system in the standing position. The analysis of the effect of various positions of the pelvis was performed using the Free Posture Model in the AnyBody Modeling System software. Simulated positions involving various values of pelvis inclination ranged from the extreme pelvic retroposition (-7°) through normative values (0-23°) to the extreme pelvic anteversion (33°). The lowest resultant reaction forces in the intervertebral joints recorded for an angle of inclination restricted within the range of 9-27° and segment L5-S1 amounted to less than 0.7 BW. A change in the pelvic inclination from the normative values towards retroposition or anteversion resulted in the increased muscular activity of the erector spinae, transverse abdominal muscles as well as internal and external oblique muscles. Regarding the lower limbs, changes in the activity were observed in the biceps femoris muscle, iliac muscle, gluteus minimus, gluteus medius and the gluteus maximus. The results obtained in the research-related tests confirmed that the pelvic inclination affects loads present in the musculoskeletal system. The abovenamed results will be used to develop therapeutic exercises aimed to reduce loads present in the musculoskeletal system. The aforesaid exercises will be used to teach participants how to properly position their pelvis and how to activate individual groups of muscles.

Habitat extremity and conservation management stabilise endangered calcareous fens in a changing world

Calcareous fens represent an endangered type of peatlands, acting as refugia for stress-tolerant species in the currently changing landscapes. The resurveys across many regions have reported their recent disappearance or deterioration despite both the extreme habitat conditions (carbonate richness, presence of calcareous tufa, nutrient limitation, high water level) and conservation management. To test the stability of their biotic communities in different environmental and management configurations, we repeatedly sampled molluscs (terrestrial and aquatic), vascular plants, and bryophytes at 30 calcareous fens in the Inner Western Carpathians (Slovakia, Poland) after 13–17 years of warm summers and land-use changes. We found a small yet statistically significant effect of sampling period (old versus new survey) on the species composition of all three groups of organisms when the effect of various positions of sites along ecological gradients was controlled for. The compositional changes, interpreted with the help of Ellenberg Indicator Values, suggest an incipient succession towards grasslands and shrublands, driven by decreasing soil moisture and increasing nutrient availability. Although the number of habitat specialists did not change, the number of matrix-derived vascular plant and bryophyte species significantly increased, with six ubiquitous species of productive habitats being significantly more represented currently, while the richness of aquatic molluscs significantly decreased. Fens in which potentially strongly competitive plant species were less stressed because of less intense management and lower habitat extremity were more prone to such succession. There was no single factor that could predict the magnitude of composition changes; instead, tested factors were found to act synergistically. Conservation management was predominantly important for bryophytes, while extreme habitat conditions were predominantly important for terrestrial snails. We suggested a way how nature conservancy authorities can prioritise the management needs by applying an abiotic indicator system, with less environmentally extreme fens requiring more intense conservation management.

The effect of positioning eggs on hatchability and embryonic mortality of the Japanese quails (Coturnix Japonica)

In the last ten years, the little known about Japanese quail (Coturnix Japonica) commonly known as “Bater”, has been introduced in the progressing poultry industry of Pakistan. Study was planned to investigate the effect of various positions and condition of quail eggs on embryonic mortality, hatchability and chick weight. Total (n=150) fertile eggs of Japanese quails were grouped into A (vertical position with pointed end upward), B (vertical position with pointed end downward) and C (horizontal position) with average weight 10.87, 10.52 and 10.24 grams respectively. Statistically data was analyzed by determining the mean and standard deviation for each parameter. The group-A eggs weight was significantly higher (P<0.05) than other groups. The rate of early embryonic mortality was 8%, 12%, and 14% in dehydrated, infected and weak embryo respectively while 6% in late embryonic mortality in group-A. By the considering these parameters in group-B revealed 6%, 10%, 16% in early while 8% in late mortality. Similarly the eggs of group-C have 10%, 4%, 10% in case of early and 12% was recorded in late embryonic mortality. Hence overall embryonic mortality was low in group C (36%) compared with group A (40%) and B (40%). The hatchability rate was recorded high in group C (64%) than A (60%) and B (60%). Overall the horizontal position showed positive effects on chick weight and hatchability rate. Keywords: Egg; Embryonic mortality; Hatchability; Japanese quail; Positioning http://dx.doi.org/10.19045/bspab.2019.80091

Abstract 2413: TP53 gene mutations differently regulate ovarian cancer metabolism: Ex vivo and in vitro studies

Abstract Background: Even in the presence of oxygen, cancer cells tend to metabolize glucose into lactate instead of undergoing oxidative phosphorylation. Knowing that glucose is crucial for tumor's proliferation, new patient's treatment strategies tend to combine chemotherapy to hypoglycemic drugs. p53 is a tumor suppressor and key regulator of glycolysis in cancer cells, however highly mutated in tumors. In ovarian cancer, the majority of studies concerning p53 mutations focus on the DNA binding domain since the majority of hotspot mutations affects this region of the gene. However, mutations affecting other regions such as the proline rich domain linked directly to apoptosis may also affect the protein's expression and activity. The aim of this study is to investigate the effect of various positions of mutations in TP53 gene on glycolysis, apoptosis and transcription of p53 target genes. Material and Methods: this study was divided into two parts. The in vitro study was done using 3 ovarian cancer cell lines SKOV-3 (p53 null), Igrov-1 (WT p53) and Ovcar-3 (DNA domain mutant p53), along with the transfection of SKOV-3 cells by three different vectors: WTp53, P72R p53 and R249S p53. The ex vivo part was performed on 30 ovarian cancer biopsies. The biopsies were subjected to Tp53 immunohistochemistry and sequencing to study the mutations and their effect on p53 expression. The effect of Tp53 mutations on glucose metabolism was assayed by glucose consumption measurements, lactate production and mRNA expression of various glycolytic enzymes. To study the effect of mutations on the transcriptional activity of p53, p21 and MDM2 expression was quantified in these cells. Annexin V assay was performed on transfected SKOV-3 to study the apoptotic activity of WT and mutant p53. Results: DNA binding domain mutant cells (Ovcar-3 and R249S SKOV-3) presented a 30% increase in glucose consumption and lactate production when compared to IGROV-1 and WT SKOV-3. P72R SKOV-3 exhibited the same pattern as WTp53 cells. The increase in the mRNA expression of glucose transporters GLUT-1 and 3 and of the glycolytic enzymes PK, PFK, G6PDH and aldolase in cells with DNA binding domain mutations varied from 20 to 30%, whereas the levels of PDHa and TIGAR decreased significantly (40%). The transcriptional activity of DNA binding domain mutant cells showed a 50% decrease in comparison to WT and P72R mutant cells. The apoptotic activity of p53 was unaltered in P72R transfected SKOV-3 cells. The ex vivo results revealed a high frequency of the P72R variant in the ovarian biopsies (69%), associated with an overexpression of the p53 protein. The glycolytic and transcriptional patterns of cells extracted from these biopsies were similar to those obtained in transfected cells. Conclusion: Though both DNA-binding and proline-rich domains mutations lead to p53 overexpression, only the first type promotes Warburg effect and could have the worst patient's prognosis. Citation Format: Stephanie Antoun, David Atallah, Roula Tahtouh, Malak Moubarak, Nada Alaeddine, George Hilal. TP53 gene mutations differently regulate ovarian cancer metabolism: Ex vivo and in vitro studies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2413.

Different TP53 mutants in p53 overexpressed epithelial ovarian carcinoma can be associated both with altered and unaltered glycolytic and apoptotic profiles

Backgroundp53 is a tumor suppressor and key regulator of glycolysis in cancer cells, however highly mutated in tumors. In ovarian cancer, studies concerning p53 mutations focus on the DNA binding domain since the majority of hotspot mutations affects this region. Yet, mutations in other regions such as the proline rich domain may also affect the protein’s expression and activity. The aim of this study is to investigate the effect of various positions of mutations in TP53 gene on glycolysis, apoptosis and transcription of p53 target genes.MethodsMutations frequency and their effect on p53 expression were assessed by PCR-SSCP, sequencing and immunohistochemistry on 30 ovarian cancer biopsies. Six tumors were cultured, as well as SK-OV-3, OVCAR-3 and Igrov-1. SK-OV-3 cells were transfected with 2 TP53 mutants. p53 transcriptional activity was assayed by qPCR, apoptosis by flow cytometry and glycolysis by glucose and lactate measurements, with quantification of glycolytic enzymes expression.ResultsOur results showed a high frequency of the P72R mutant, associated with p53 overexpression in the ovarian biopsies. However, P72R mutant cells showed similar apoptosis and glycolysis as WT cells. DNA binding domain mutations decreased the transcriptional activity of the protein and increased glucose consumption and lactate production.ConclusionDespite the overexpression of the P72R mutated protein in the biopsies, it showed a similar apoptotic activity and glucose regulation ability as WT p53. Knowing that p53 expression status is used for chemotherapeutic approaches and prognosis in ovarian cancer, the results obtained highlight the importance of locating TP53 mutations.

Two-dimensional flow instability induced by natural convection in a square enclosure with four inner cylinders. Part II: Effect of various positions of inner cylinders

Two-dimensional numerical simulations were conducted for the natural convection phenomena in a cold square enclosure containing four hot circular cylinders with Rayleigh number in the range of 103≤Ra≤106 and a Prandtl number of Pr=0.7. The immersed boundary method (IBM) was used to capture the virtual wall boundary of the cylinders based on the finite volume method (FVM). In the present study, the variation in the vertical position of the cylinders was compared with those in the diagonal and horizontal positions. The change in the flow and thermal structures and corresponding heat transfer characteristics were investigated in regard to the transition of the flow regime from the steady state to the unsteady state at a relatively high Rayleigh number. In addition, the effects of the cylinder positions of a rectangular array in the square enclosure on the heat transfer characteristics are highlighted.

Strengthening of a RC Beam using Synthetic FRP Laminates

Objectives: The present research paper summarizes the study of use of synthetic polyester fiber for the strengthening of the reinforced concrete beams. Methods: In this experimental study, ten reinforced concrete beams were casted. They were externally strengthened with the help of synthetic polyester fiber using epoxy resin and hardener. The application of Polyester Fibre Reinforced Polymer sheets for strengthening of RC beams was done in u-wrap and bottom wrap. The effect of this on ultimate load carrying capacity and flexural strength was examined. Findings: The reinforced concrete beams were tested to failure using symmetrical two point concentrated static loading system. The results were found experimentally on load, deflection and failure types of each of the beams. The effect of various positions of wrapping of Polyester Fiber Reinforced Polymer on ultimate load carrying capacity was investigated. The results obtained showed increase in the ultimate load carrying capacity and flexural strength of the beams as compared with the control beam. The ultimate load obtained with polyester fibre reinforced beam was, however less compared to Carbon/Glass/Aramid as recorded in the literature. But the results obtained were encouraging and useful. Applications: Defects occur in reinforced concrete due to many factors like-age, corrosion of steel reinforcement, defective structural design etc. Fibre reinforced polymers can be successfully utilized for rehabilitation of these RC structures.

Ozone production of hollow-needle-to-mesh negative corona discharge enhanced by dielectric tube on the needle electrode

For the hollow-needle-to-mesh negative corona discharge in air, we studied the effect of placing the dielectric tube on the needle electrode and the effect of various positions of the end of this tube with respect to the tip of the needle electrode on the concentration of ozone produced by the discharge, the ozone production yield and the discharge V–A characteristics. We found that the placement of the dielectric tube on the needle electrode with a suitable position of this tube end with respect to the tip of the needle electrode for a particular discharge power led to a more than fourfold increase in the concentration of ozone produced by the discharge and also, for a constant airflow, the ozone production yield.

Qualitative and quantitative assessment of relationship between mandibular third molar and angle fracture on North Indian population: A clinico-radiographic study.

Objective:To assess the relationship between impacted mandibular third molar presence and the risk for mandibular angle fracture with the effect of various positions of mandibular third molar and the risk of mandibular angle fracture.Materials and Methods:In the North Indian territory, a total of 289 patients with mandibular angle fractures were studied and evaluated for the possible relationship with impacted third molar on the basis of clinical and panoramic radiographical findings.Results:Results that confirmed the highest risk for mandibular angle fracture was associated with mesioangular angulations (45.42%) followed by vertical (26.34%), distoangular in sequence and least risk was found with bucco-version angulations (2.67%) according to Winter's classification. Additionally, the highest risk of mandibular angle fracture was reported with partially erupted third molar (47.75%), followed by erupted (23.53%) and unerupted third molar (19.38%).Conclusion:The risk for mandibular angle fracture is not only affected by status of eruption, angulations, position, number of roots present in third molar but also by the distance of mandibular third molar from inferior border of mandible and the percentage of remaining amount of bone at the mandibular angle region.

Enhanced properties of organic electroluminescent devices with cesium chloride ultra-thin layer

The effect of various positions and thicknesses of cesium chloride (CsCl) layer in organic light-emitting diodes is investigated. The basic device configuration is indium–tin–oxide (ITO)/N,N′-bis-(1-naphthl)-diphenyl-1,1′-biphenyl-4,4′-diamine (NPB)/tris (8-hydroxyquinoline) aluminum (Alq3)/aluminum (Al). The following results are demonstrated. When the CsCl layer is placed at the Alq3/Al interface and closer to the Al cathode inside Alq3 layer, the effective barrier to electron injection is reduced due to the reaction between Cs and Al. As a result, the injection of electrons and holes is more balanced and the efficiency is enhanced from 1.83 to 3.49cd/A. And as an electron injection layer, CsCl can be comparable with lithium fluoride (LiF). If the distance of the CsCl layer is more than 20nm from Alq3/Al interface inside Alq3 layer, the luminance and efficiency are enhanced but the injection is not increased, which is attributed to trap sites induced by the CsCl layer. The decrease of luminance and efficiency is observed when the CsCl layer is located at the NPB/Alq3 interface. The reason is exciton quenching due to charge transfer from metal Cs to organic material Alq3. The CsCl layer inside NPB layer plays a role of hole blocking. More balanced injection of carriers is expected. Subsequently, both luminance and efficiency are enhanced by 34% and 60%, respectively. When the cathode of lithium fluoride (LiF)/Al is used, the device efficiency is also improved from 4.0 to 5.0cd/A by inserting the CsCl layer inside NPB layer. However, the improvement is not observed for the device with the CsCl layer inserted inside Alq3 layer in LiF/Al-OLED.

Part 6: Defibrillation

Part 6: Defibrillation

Positioning During CT Gastrography in Patients with Gastric Cancer: the Effect on Gastric Distension and Lesion Conspicuity

ObjectiveWe wanted to prospectively evaluate the effect of various positions of the patient on gastric distension and lesion conspicuity during performance of CT gastrography (CTG).Materials and MethodsOne hundred thirteen consecutive patients with gastric cancer underwent CTG in the 30° left posterior oblique (LPO), supine, and prone positions. Two radiologists scored (a grade from 1-4) the degree of gastric distension and the lesion conspicuity according to the three scanning positions and the three gastric portions. Two- (2D) and three-dimensional (3D) images were used for analysis. Finally, these data were compared with the endoscopic findings and surgical results.ResultsThe mean scores of gastric distension and lesion conspicuity for the LPO and supine positions were higher than those for the prone position (p < 0.001) in the gastric middle and lower portions. However, there was no significant difference between the LPO and supine positions (p ≥ 0.21). As for the gastric upper portion, the mean scores of gastric distension in the prone position were higher than those in the two other positions (p < 0.001). The prone position showed better lesion conspicuity than the two other positions for only one of two cases of gastric cancer in the upper portion of the stomach.ConclusionCTG performed in the LPO position or the supine position combined with CTG performed in the prone position is optimal for achieving good gastric distension and evaluating the lesion conspicuity of gastric cancer.

Fresh fractures of the scaphoid : A rationale method of treatment

Background : Scaphoid, among all carpal bones, is very vulnerable for fracture due to its unique shape and situation with greater articular surface. All scaphoid fractures are being treated with below elbow POP thumb spica casts keeping hand in ball throwing position. A few scaphoid fractures through the waist take longer time to unite, if not end in nonunion. These fractures were found to be displaced unimpacted trans-scaphoid fractures through the waist. Method : The effect of various positions of hand, wrist and forearm over unimpacted displaced scaphoid fractures through the waist were studied on dissected hand specimens and in patients with skiagrams. It was observed that possible radial deviation of hand over neutrally held wrist and forearm would result in anatomical reduction with impaction between the fragments. Added compression effect at site of fracture, necessary for early fracture healing, is produced by passively abducting the first metacarpal bone. Results : Of 68 scaphoid fractures under study, 24 and 41 were displaced and undisplaced ones through the waist respectively. All of them united in eight to ten weeks time as any fracture, when immobilised undisturbed with anatomic reduction and added compression between the fragments except one displaced fracture which took eight more weeks of immobilization for union and revascularilization of proximal fragment. Conclusion : This study showed that all scaphoid fractures in particular those through waist when rigidly immobilized unite as any fracture in eight to ten weeks provided the proximal fragment maintains proper blood supply. Otherwise it would further eight week of immobilization for the proximal fragment to get revascularize following union.

Changes in Position and Intraabdominal Pressure do not Influence Oropharyngeal Leak Pressure in Laparoscopic Surgery Maintained with a ProSeal Laryngeal Mask Airway

Background: It is known that pneumoperitoneum and changes of body position during laparoscopic surgery influenced peak inspiratory pressure (PIP). We asked the question whether oropharyngeal leak pressure (OLP) is changed by changes in intraabdominal pressure and position during laparoscopic surgery with a ProSeal laryngeal mask airway (PLMA). Since gynecological laparoscopic surgery (Lap-Gy) and laparoscopic cholecystectomy (Lap-C) require different surgical positions, we included both surgeries in this study so that we could investigate the effects of various positions on OLP. Methods: Lap-Gy (n = 15) was performed in the trendelenburg position combined with the lithotomy position, whereas Lap-C (n = 10) was performed in the reverse trendelenburg position. The measured variables were PIP and OLP. We also marked the fiberoptic score to determine the intraoral position (FP) of the PLMA. OLP was measured using a manometric stability test. The variables were measured in a regular sequence as follows: S-0-0, L-0-0, L-0-15, L-( -15)-15, L-( -30)-15 in Lap-Gy and S-0-0, S-0-15, S-( +15)-15, S-(+ 30)-15 in Lap-C. At each measured point, the capital S means supine and L lithotomy. Intermediate numbers with a '' superscript are table angles to the horizontal plane (degrees) , '-' means the trendelenburg position and '+', the reverse trendelenburg position, and the last number represents intraabdominal pressure (mmHg). Results: PIP was significantly increased when L-0-0 changed to L-0-15, L-0-15 to L-(-15)-15 and L-(-15)-15 to L-(-30)-15 in Lap-G, and when S-0-0 was changed to S-0-15 in Lap-C (P

Low-cost planting stock production of bamboo (Dendrocalamus strictus Roxb.) using culm cuttings

A study was conducted to see the effects of various positions of cutting (basal, middle and apical) and growth regulators/chemicals on rooting and sprouting of culm cuttings of bamboo (Dendrocalamus strictus Roxb.). The growth regulators/chemicals used were also evaluated for their cost effectiveness. The findings indicated that coumarin and calcium chloride gave the best response in initiating the rooting in culm cuttings compared to other auxins tested. The most optimal cutting position was found to be the basal position of culm for the best interaction with the chemicals. These two chemicals were the most cost-effective and are recommended for low cost mass production of planting stock of bamboo for large-scale plantation programmes.

多段土壌層法による生物系排水処理 モデル装置の送気位置の違いによる処理能力の比較

The effects of various positions of aeration in Multi-Soil-Layering (MSL) method of bio-genic waste water treatment were investigated. Porous aeration pipes were installed in upper, middle, and lower positions in model MSL systems. Each model MSL packed in 10X50X60cm sized acrylic box. Air was supplied at the rate of 48000 l·m-3·d-1 through the porous pipes installed at various positions. Loading rate of waste water was 288 l·m-2·d-1. In the upper position of aeration, clogging was prevented and nitrogen removal was efficient. But efficiency of aeration was low for high level of removal of COD·BOD and T-P, because air leaked from surface of the system. In the middle position of aeration, the efficiency of T-P removal and decomposition of organic matter were high because of the efficient aeration to create relatively large aerobic parts in the MSL. But nitrogen removal was low. Because of nitrate was leaching. It was thought that anaerobic parts were too small to efficient denitrification. In the lower position of aeration, clogging was happened at the early stages of treatments. Fe(II) and Mn(II) were oxidized efficiently to prevent the solubilization. COD·BOD of final effluent water was also low. Based on this study, if only one aeration position has to be selected, the appropriate aeration position was considered to be the position between the first and second of soil layers of MSL. This aeration position may prevent clogging effectively. Large aerobic condition may contribute to efficient phosphorus and organic matter removals. Nitrogen removal may also be enhanced because of nitrification of the upper position and denitrification of the lower position.However, since each upper, middle, and lower position showed different efficiency characteristics on treatments, the positioning of aeration and the operational condition should be selected depending on the given target of the treatment, including the combinations of the two positions, upper/lower, upper/middle, and middle/lower.