Categorizing tumor size as a prognostic factor for risk of relapse of hepatocellular carcinoma (간세포암종의 재발 위험과 관련된 한 예후인자로서의 종양의 크기의 범주화)
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- The Korean Journal of Applied Statistics
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- v.15 no.1
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- pp.1-8
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- 2002
Categorizing prognostic factors is very useful for a disease diagnosis, determination of treatment and study eligibility criteria. Methods often used to categorize factors are to select a cutpoint by biological theory, by graphical examination, by the minimum p-value approach. The last method involves multiple testing, and several methods for adjusting p-values have been developed. This study determines the cutpoint of tumor size to separate patients of high risk of relapse after hepatic resection of hepatocellular carcinoma.
An optimal controller, e.g. LQG controller, may not be realistic in the sense that the required control power may not be achieved by existing actuators, and the measured output is not satisfactory. To be realistic, the controller should meet such constraints as sensor or actuator limitation, performance limit, etc. In this paper, the lnput/Output Variance Constrained (IOVC) control problem will be considered from the viewpoint of mathematical programming. A dual version shall be developed to solve the IOVC control problem, whose objective is to find a stabilizing control law attaining a minimum value of a quadratic cost function subject to the inequality constraint on each input and output variance for a stabilizable and detectable plant. One approach to the constrained optimization problem is to use the Kuhn-Tucker necessary conditions for the optimality and to seek an optimal point by an iterative algorithm. However, since the algorithm uses only the necessary conditions, the convergent point may not be optimal solution. Our algorithm will guarantee a sufficiency.
This paper proposes the heuristic approach for the generalized GT(Group Technology) problem to consider the restrictions which are given the number of cell, maximum number of machines and minimum number of machines. This approach is classified into two stages. In the first stage, we use the similarity coefficient method which is proposed and calculate the similarity values about each pair of all machines and align these values in descending order. If two machines which is selected is possible to link the each other on the edge of machine cell and they don't have zero similarity value, then we assign the machines to the machine cell. In the second stage, it is the course to form part families using proposed grouping efficacy. Finally, machine-part incidence matrix is realigned to block diagonal structure. The results of using the proposed approach are compared to the Modified p-median model.
Rejection of ionic solutes by reverse osmosis (RO) and nanofiltration (NF) membranes is controlled mainly by electrochemical interaction as well as pore size, but it is very difficult to directly evaluate such electrochemical interaction. In this work, we used an inverse HPLC method to investigate the interaction between ionic solutes and poly (m- phenylenediaminetrimesoyl) (PPT), a polymer similar to the skin layer of polyamide RO and NF membranes. Silica gel particles coated with PPT were used as the stationary phase, and aqueous solutions of the ionic solutes were used as the mobile phase. Chromatographs obtained for the ionic solutes showed features typical of exclusion chromatographs: the ionic solutes were eluted faster than water (mobile phase), and the exclusion intensity of the ionic solute decreased with increasing solute concentration, asymptotically approaching a minimum value. The charge density of PPT was estimated to be ca. 0.007 mol/L. On the basis of minimum exclusion intensity, the exclusion distances between a salt and neutralized PPT was examined, and the following average values were obtained: 0.49 nm for 1:1 salts, 0.57 nm for 2:1 salts, 0.60 nm for 1:2 salts, and 0.66 nm for 2:2 salts. However,
Pseudomonas aeruginosa and Staphylococcus aureus are the two most frequently encountered pathogens responsible for chronic wound infections, often coexisting in such cases. These infections exhibit heightened virulence compared to single infections, leading to unfavorable patient outcomes. The interaction among microorganisms within polymicrobial infections has been shown to exacerbate disease progression. Polymicrobial infections, prevalent in various contexts such as the respiratory tract, wounds, and diabetic foot, typically involve diverse microorganisms, with Pseudomonas aeruginosa and Staphylococcus aureus being the most commonly identified pathogens. This study aimed to compare the growth patterns of bacteria under a concentration gradient of toxic chemicals, focusing on a Gram-negative strain of Pseudomonas aeruginosa and a Gram-positive strain of Staphylococcus aureus. The minimum inhibitory concentration (MIC), which signifies the concentration at which bacterial growth is inhibited, was determined by performing broth microdilution and assessing the bacteria's growth curves. The growth curves of both Pseudomonas aeruginosa and Staphylococcus aureus were confirmed, and the exponential growth phases were applied to calculate the doubling times of bacteria. The MIC value for each toxic chemical was determined through broth microdilution. These results allowed for the identification of disparities in growth rates between Gram-positive and Gram-negative bacteria, as well as differences in resistance to individual toxic substances. We expect that this approach has a strong potential for further development towards the innovative treatment of bacteria-associated infections.
The purpose of this study was to assess the results of arthroscopic subacromial decompression in patients with chronic impingement and to evaluate the results according to the rotator cuff pathology. We evaluated the clinical results of treatment for chronic impingement syndrome in 28 patients from Feb 1996 to Feb 1997. There were twenty men and eight women in age from 24 to 72 years (mean age 51) with dominant arm involvement in sixteen patients. Follow up evaluations averaged 15(range 12-24)months. The average duration of symptoms were 15(range 660)months. The final diagnoses which were based on the physical examination, plain radiographs and arthroscopic findings, were stage II impingement in 16 patients and stage ill impingement in 12 patients. We excluded the patients with acromioclavicular arthritis or glenohumeral instability in this study. All patients were managed non-operatively a minimum of six months. During the operation we performed contouring and smoothing the acromial undersurface and only resecting of the anterolateral band of the coracoacromial ligament. The clinical results were quantitated using UCLA shoulder rating score. Satisfactory results were obtained in 23(80%) patients. Unsatisfactory results were obtained in 5(18%) patients with posterior cuff tear. The average UCLA pain score showed significant improvement from 2.8(constant pain) to 7.2(present during heavy activities) at final follow up. The function and active forward flexion scores also increased from their preoperative value. There was no significant differences according to the surface and severity of tear and NeeI' stage (P>0.05). These results compared favorably with those reported following open acromioplasty. While arthroscopic subacromial decompression is a demanding technique with a learning curve, it is a reliable treatment for chronic impingement syndrome. A less aggressive approach to subacromial decompression and preserving the posteromedial band of the coracoacromialligament does not appear to compromise results.
The search for materials that serve as good shields for radiation has become very important in light of the increasing exposure to ionizing radiation in various vital sectors. The aim is to search for novel materials with better radiation shielding properties that are stable, nontoxic, and abundant and environment friendly. The solidstate reaction approach has been used to synthesize a few ceramics, including BaZrXTi1-XO3, Ba1-XLaXTiO3 and Ba1-XLaXZrXTi1-XO3 (with x = 0.10) i.eBaZr0.10Ti0.90O3 (BZT), Ba0.90La0.10TiO3 (BLT), and Ba0.90La0.10Zr0.10Ti0.90O3 (BLZT). The density of the prepared samples varies from 6.3471 to 11.6003 g/cm3. The X-ray diffraction technique, shows strong peaks to confirm the crystalline structure of prepared ceramic samples. Using the G-P fitting approach, the advanced radiation shielding parameters (build-up factor) have been evaluated in the photon energy region of 1.5 keV-15 MeV. It is observed from the results that exposure buildup factor (EBF) and energy absorption buildup factor (EABF) are maximum for BLZT and has the minimum value for BZT in the entire photon energy regime. The results of this work should be useful in radiation shielding applications such as in industry, medicine, and nuclear engineering.
Temporal changes of Chl-α, physical and chemical factors were investigated by diurnal observation at 2-hour interval at three fixed stations in the western Chinhae Bay from 12 Aug. to 13 Aug. 1999. Difference of dissolved oxygen between surface and bottom layer was maximum when the thermocline were strong. Organic distribution such as COD was affected by the growth of phytoplankton. Limitting factor was nitrogen, that is, inorganic nitrogen plays a significant role on regulating the algal growth. Surface distribution of dissolved inorganic nitrogen was very low compared to bottom layer by uptake of organisms. Maximum value of Chl-α at station C2 and C11 were observed from subsurface layer, ranges of which exceeded possibility concentration of red tide outbreak, 10 mg/㎥. On the other hand, that of C15 exist at surface layer. In this area, DIN and DIP concentrations increased by input sources such as rainfall and benthic flux before the bloom of phytoplankton. Accumulation of phytoplankton occurred at subsurface layer by the rapid uptake of DIN, especially nitrate ion, when strong thermocline existed as approach to the afternoon, which led to the increase of organics in water column and oxygen deficiency water mass at bottom layer until late at evening. Since then, DIN increases gradually as water temperature decrease to minimum. The quantitative understanding of nitrogen of fluxed to and from the various sources is necessary for environmental management.
The wall shear stress in the vicinity of end-to end anastomoses under steady flow conditions was measured using a flush-mounted hot-film anemometer(FMHFA) probe. The experimental measurements were in good agreement with numerical results except in flow with low Reynolds numbers. The wall shear stress increased proximal to the anastomosis in flow from the Penrose tubing (simulating an artery) to the PTFE: graft. In flow from the PTFE graft to the Penrose tubing, low wall shear stress was observed distal to the anastomosis. Abnormal distributions of wall shear stress in the vicinity of the anastomosis, resulting from the compliance mismatch between the graft and the host artery, might be an important factor of ANFH formation and the graft failure. The present study suggests a correlation between regions of the low wall shear stress and the development of anastomotic neointimal fibrous hyperplasia(ANPH) in end-to-end anastomoses. 30523 T00401030523 ^x Air pressure decay(APD) rate and ultrafiltration rate(UFR) tests were performed on new and saline rinsed dialyzers as well as those roused in patients several times. C-DAK 4000 (Cordis Dow) and CF IS-11 (Baxter Travenol) reused dialyzers obtained from the dialysis clinic were used in the present study. The new dialyzers exhibited a relatively flat APD, whereas saline rinsed and reused dialyzers showed considerable amount of decay. C-DAH dialyzers had a larger APD(11.70
The wall shear stress in the vicinity of end-to end anastomoses under steady flow conditions was measured using a flush-mounted hot-film anemometer(FMHFA) probe. The experimental measurements were in good agreement with numerical results except in flow with low Reynolds numbers. The wall shear stress increased proximal to the anastomosis in flow from the Penrose tubing (simulating an artery) to the PTFE: graft. In flow from the PTFE graft to the Penrose tubing, low wall shear stress was observed distal to the anastomosis. Abnormal distributions of wall shear stress in the vicinity of the anastomosis, resulting from the compliance mismatch between the graft and the host artery, might be an important factor of ANFH formation and the graft failure. The present study suggests a correlation between regions of the low wall shear stress and the development of anastomotic neointimal fibrous hyperplasia(ANPH) in end-to-end anastomoses. 30523 T00401030523 ^x Air pressure decay(APD) rate and ultrafiltration rate(UFR) tests were performed on new and saline rinsed dialyzers as well as those roused in patients several times. C-DAK 4000 (Cordis Dow) and CF IS-11 (Baxter Travenol) reused dialyzers obtained from the dialysis clinic were used in the present study. The new dialyzers exhibited a relatively flat APD, whereas saline rinsed and reused dialyzers showed considerable amount of decay. C-DAH dialyzers had a larger APD(11.70