Technical Efficiency in the Iron and Steel Industry: A Stochastic Frontier Approach

In this paper we examine the technical efficiency of firms in the iron and steel industry and try to identify the factors contributing to the industry's efficiency growth, using a time-varying stochastic frontier model. Based on our findings, which pertain to 52 iron and steel firms over the period of 1978-1997, POSCO and Nippon Steel were the most efficient firms, with their production, on average, exceeding 95 percent of their potential output. Our findings also shed light on possible sources of efficiency growth in the industry. If a firm is government-owned, its privatization is likely to improve its technical efficiency to a great extent. A firm's technical efficiency also tends to be positively related to its production level as measured by a share of the total world production of crude steel. Another important source of efficiency growth identified by our empirical findings is adoption of new technologies and equipment. Our findings clearly indicate that continued efforts to update technologies and equipment are critical in pursuit of efficiency in the iron and steel industry.

The Prognostic Implications of Cystic Change in Clear Cell Renal Cell Carcinoma

Background : Cystic renal cell carcinoma has been reported to have a good prognosis. However, previous studies included cases of multilocular cystic renal cell carcinoma, which has an excellent prognosis, and renal cell carcinoma with cystic necrosis, which has an adverse prognosis. Therefore, we analyzed the prognostic influence of cystic change in clear cell renal cell carcinoma after excluding those morphological features. Methods : We identified 225 patients with clear cell renal cell carcinoma who underwent nephrectomy between 2001 and 2003. The clinicopathologic features were compared with clinical outcomes. Results : Cystic change in clear cell renal cell carcinoma (n = 66) was significantly associated with younger patient age (< 55), smaller tumor size (<= 4 cm), lower pT stage (pT1, T2), M0 stage at initial diagnosis, lower tumor, node, and metastasis stage (I, II), and lower nuclear grade (1, 2). Patients with cystic change in clear cell renal cell carcinoma had significantly longer cancer-specific (p = 0.015) and progression-free survival (p = 0.004) than those without cystic change, by univariate analysis. Multivariate analysis revealed that cystic change significantly decreased the risk of cancer progression (risk ratio, 0.27; 95% confidence interval, 0.11 to 0.69). Conclusions : In patients with clear cell renal cell carcinoma, cystic change is a good independent predictor for survival.This work was supported by grant No. 04-2009-007 from the SNUH Research Fund.Jemal A, 2009, CA-CANCER J CLIN, V59, P225, DOI 10.3322/caac.20006Lopez-Beltran A, 2009, INT J UROL, V16, P432, DOI 10.1111/j.1442-2042.2009.02302.xGobbo S, 2008, AM J SURG PATHOL, V32, P1239Gong K, 2008, J CANCER RES CLIN, V134, P433, DOI 10.1007/s00432-007-0302-1Webster WS, 2007, UROLOGY, V70, P900, DOI 10.1016/j.urology.2007.05.029Lopez-Beltran A, 2006, EUR UROL, V49, P798, DOI 10.1016/j.eururo.2005.11.035Suzigan S, 2006, AM J CLIN PATHOL, V125, P217, DOI 10.1039/AH6FC77PYR2V6YAYFrank I, 2005, J UROLOGY, V173, P1889, DOI 10.1097/01.ju.0000158043.94525.d6Patard JJ, 2005, J CLIN ONCOL, V23, P2763, DOI 10.1200/JCO.2005.07.055Kim H, 2004, HUM PATHOL, V35, P1556, DOI 10.1016/j.humpath.2004.06.011Ficarra V, 2004, EUR UROL, V46, P559, DOI 10.1016/j.eururo.2004.07.002Han KR, 2004, UROL ONCOL-SEMIN ORI, V22, P410, DOI 10.1016/S1078-1439(03)00173-XImura J, 2004, APMIS, V112, P183Cheville JC, 2003, AM J SURG PATHOL, V27, P612Frank I, 2002, J UROLOGY, V168, P2395, DOI 10.1097/01.ju.0000035885.91935.d5Nassir A, 2002, UROLOGY, V60, P421GREENE FL, 2002, AJCC CANC STAGING MACorica FA, 1999, J UROLOGY, V161, P408Bielsa O, 1998, BRIT J UROL, V82, P16USUBUTUN A, 1998, INT UROL NEPHROL, V30, P391LYNCH CF, 1995, CANCER, V75, P316HARTMAN DS, 1986, UROLOGY, V28, P145

Comparative study on melanin production and collagen expression profile of polyphenols and their glycosides

A total of twenty different polyphenol aglycones and their biochemically synthesized glycoside derivatives were accessed for cell toxicity, collagen synthesis and melanin content inhibition assays to illustrate the double-edged sword role of glycobiology, in particular, modification of hydroxyl group in polyphenol structure without glycone moiety over anti-aging and defense to oxidative stress in skin dermatology. All molecules at (0.1-200) µM concentration inhibited cell growth in a dose dependent manner on human dermal fibroblast (HDF) and melanoma skin cancer (B16F10) cells. At lower concentrations of (0.1-10) µM, most of the molecules were nontoxic to HDF cells, while the same molecules were toxic to B16F10 cells except astilbin (6), baicalein (13), baicalein 7-O-β-D-glucoside (14) and mangostin (18). Results showed that two molecules, quercetin (1) and diosmin (17), inhibited melanogenesis in α-melanocyte stimulating hormone (α-MSH)-stimulated melanoma skin cancer cells (B16F10) in comparison to the control at 0.1 µM concentration, indicating the possible use of these molecules in skin-whitening products. Similarly, the maintenance of collagen in HDF cells was found to be highly activated by the compound, kaempferol (11), at 1.0 µM concentration, at which the cell viability was above 95%. Compound 1, apigenin 7-O-β-D-glucoside (10) andbaicalein (13) exhibited comparable collagen biosynthesis activity to control with significantly low cell toxicity

Spin-wave propagation in the presence of inhomogeneous Dzyaloshinskii-Moriya interactions

We theoretically investigate spin-wave propagation through a magnetic metamaterial with spatially modulated Dzyaloshinskii-Moriya interaction. We establish an effective Schrodinger equation for spin waves and derive boundary conditions for spin waves passing through the boundary between two regions having different Dzyaloshinskii-Moriya interactions. Based on these boundary conditions, we find that the spin wave can be amplified at the boundary and the spin-wave band gap is tunable either by an external magnetic field or the strength of Dzyaloshinskii-Moriya interaction, which offers a spin-wave analog of the field-effect transistor in traditional electronics.112sciescopu

KINEMATIC ANALYSIS OF GOLF SWING PERFORMED WITH INTENDED LATE HITTING

The purposes of this study were to analyze and compare the kinematic parameters for standard and purpose golf swings. The purpose golf swing is characterized as intended late hitting and increase displacement of ball through the air (carry). Twenty-five male college golfers were recruited as sUbjects and Science eye field 3 camera system was used to measure the parameters of deterministic model. Paired t-test was used to compare between two different golf swings and correlation coefficients between selected parameters and carry were also computed. As results, a significant difference between standard and purpose golf swings was found in terms of increasing carry. Coefficients of correlation indicated that post-impact ball velocity, pre-impact club head velocity, and meet rate were positively correlated with carry. However, backspin, and angle of release were negatively correlated with carry. These results represented that the parameters of deterministic model were very useful indicators to determine performance and the purpose swing is beneficial to increase carry

Chondrosarcoma: With Updates on Molecular Genetics

Chondrosarcoma (CHS) is a malignant cartilage-forming tumor and usually occurs within the medullary canal of long bones and pelvic bones. Based on the morphologic feature alone, a correct diangosis of CHS may be difficult, Therefore, correlation of radiological and clinicopathological features is mandatory in the diagnosis of CHS. The prognosis of CHS is closely related to histologic grading, however, histologic grading may be subjective with high inter-observer variability. In this paper, we present histologic grading system and clinicopathological and radiological findings of conventional CHS. Subtypes of CHSs, such as dedifferentiated, mesenchymal, and clear cell CHSs are also presented. In addition, we introduce updated cytogenetic and molecular genetic findings to expand our understanding of CHS biology. New markers of cell differentiation, proliferation, and cell signaling might offer important therapeutic and prognostic information in near future