Sparse-Coding-Based Computed Tomography Image Reconstruction

Computed tomography (CT) is a popular type of medical imaging that generates images of the internal structure of an object based on projection scans of the object from several angles. There are numerous methods to reconstruct the original shape of the target object from scans, but they are still dependent on the number of angles and iterations. To overcome the drawbacks of iterative reconstruction approaches like the algebraic reconstruction technique (ART), while the recovery is slightly impacted from a random noise (small amount of ℓ2 norm error) and projection scans (small amount of ℓ1 norm error) as well, we propose a medical image reconstruction methodology using the properties of sparse coding. It is a very powerful matrix factorization method which each pixel point is represented as a linear combination of a small number of basis vectors

Adaptive Total Variation Minimization-Based Image Enhancement from Flash and No-Flash Pairs

We present a novel approach for enhancing the quality of an image captured from a pair of flash and no-flash images. The main idea for image enhancement is to generate a new image by combining the ambient light of the no-flash image and the details of the flash image. In this approach, we propose a method based on Adaptive Total Variation Minimization (ATVM) so that it has an efficient image denoising effect by preserving strong gradients of the flash image. Some numerical results are presented to demonstrate the effectiveness of the proposed scheme

Clinical Significance of p16 Protein Expression Loss and Aberrant p53 Protein Expression in Pancreatic Cancer

Pancreatic cancer is a disease with poor prognosis mainly due to low resection rates and late diagnosis. To increase resectability and improve survival rates, a better understanding of pancreatic cancer pathogenesis and more effective screening techniques are required. New methods, such as genetic and molecular alterations, may suggest novel approaches for pancreatic cancer diagnosis and treatment. We immunohistochemically investigated 44 formalin-fixed, paraffin-embedded specimens of pancreatic ductal adenocarcinoma using monoclonal anti-p16 antibodies and monoclonal anti-p53 antibodies. The expressions of p16 and p53 proteins were compared using the Chi-square test with SPSS. Disease-free survival was analyzed using the Kaplan-Meier method, verified by the Log-Rank test. Loss of p16 expression was noted in 20 (45.5%) cases and aberrant p53 protein expression was detected in 14 (31.8%) cases. Loss of p16 expression was associated with a higher incidence of lymph node metastasis (p=0.040) and a more advanced stage (p=0.015), although there was no significant correlation between p16 expression and survival. Aberrant p53 protein expression correlated with histologic grade (p=0.038). Disease-free survival rate was significantly lower in the aberrant p53 protein positive group compared to the negative group (p=0.029). From our results, we suggest that p53 is not a prognostic factor; however, p16 and p53 genes do play important roles in the progression of pancreatic ductal adenocarcinoma

The Impact of Overactive Bladder on Health-Related Quality of Life, Sexual Life and Psychological Health in Korea

Purpose We aimed to estimate the prevalence of overactive bladder (OAB) in Korea, to assess the variation in prevalence by sex and age, and to measure the impact of OAB on quality of life. Methods A population-based, cross-sectional telephone survey was conducted between April and June 2010 with a questionnaire regarding the prevalence of OAB, demographics, and the impact of OAB on quality of life. A geographically stratified random sample of men and women aged ≥30 years was selected. Results The overall prevalence of OAB was 22.9% (male, 19%; female, 26.8%). Of a total of 458 participants with OAB, 37.6% and 19.9% reported moderate or severe impact on their daily life and sexual life (5.6% and 3.5%, respectively, in participants without OAB). Anxiety and depression were reported by 22.7% and 39.3% of participants with OAB, respectively (9.7% and 22.8%, respectively, in participants without OAB). Only 19.7% of participants with OAB had consulted a doctor for their voiding symptoms, but 50.7% of respondents with OAB were willing to visit a hospital for the management of their OAB symptoms. Conclusions This study confirmed that OAB symptoms are highly prevalent in Korea, and many sufferers appear to have actively sought medical help. OAB has severe effects on daily and sexual life as well as psychological health

Effects of ProstagIand in F2a on the Spontaneous Contractions and Electrical Activities in the Circular Smooth MuscIe of the Guinea-Pig Stomach

Effects of PGF2a and indomethacin on the mechanical and electrical membrane properties of guinea-pig antral smooth muscle were studied using microeletrodes and tension recording technique and whole cell patch clamp technique. In this tissue, indomethacin inhibited the contractility and such an effect was reversed by PGF2a. PGF2a increased spontaneous contractions potently and the frequency and amplitudes of slow waves were also enhanced. PGF2a-induced contractions were not abolished by the pretreatment with nifedipine or by the nominal Ca2+-free condition but were abolished by pretreatment with La3+ or absolute Ca2+-free condition. Ionic currents were also measured by whole cell voltage clamp technique. PGF2a increased the size of voltage operated Ca2+ inward currents, and Ca-dependent K+ outward currents, but had no effect on sustained outward currents. From the above results, it is assumed that PGF2 a acts as an endogenous prostaglandin in the gastric antrum of the guinea-pig. PGF2a has promoting effects on electrical activities and such effects seem to contribute to the increase of contraction, but the greatest part of the increase of contraction is due to receptor-mediated increase of [Ca2+]i. Several possible mechanisms were suggested for the receptor-mediated [Ca2+]i increase

Deep Level in Heavily Zn-doped InP Layers Implanted with Ti and Ti/P

We have investigated deep level peaks observed in the photoluminescence spectrum of heavily Zn-doped InP layers grown by metalorganic chemical vapor deposition at energies centered at 0.89 and 0.94 eV. These peaks are enhanced when the samples are implanted with Ti. When P is co-implanted, however, the intensity of these peaks decrease, and at an increased dosage, the peaks disappear from the spectrum. The peaks are, therefore, dependent on the phosphorus vacancy produced by the excessive Zn doping or the implant damage. Hall measurement data show that the Ti/P-implanted p-type InP layer is converted to n type with its sheet resistance decreasing and the donor activation of Ti increasing for higher P co-implant dose. In addition, the photoluminescence intensity of the deep level peaks is highly correlated with the sheet resistance.This work was financially supported in part by KOSEF through OERC Grant No. 97K3-0809-02-06-1 and by the Ministry of Education of Korea through Grant No. ISRC-97- E-3205

Low Temperature Photoluminescence Characteristics of Zn-doped InP Grown by Metalorganic Chemical Vapor Deposition

Zn-doped InP layers were obtained by two different doping techniques: in situ doping by low pressure metalorganic chemical vapor deposition, and thermal diffusion from a Zn-containing film. Their low temperature photoluminescence ~PL! characteristics were studied, and compared. In Zn-diffused InP, the deep donor to acceptor transition was the most dominant transition and other transitions such as the band edge transition and the band to band or shallow donor to acceptor transition were not observed at the excitation power of 10 mW. On the other hand, well resolved band edge peaks and the band or shallow donor to acceptor transition peak were observed for in situ Zn doped InP, implying that less interstitial Zn atoms were generated during in situ doping. Saturation of the hole concentration at 1.531018 cm3 was observed in in situ Zn doped InP, and the changes in PL characteristics at the saturation level were extensively studied. Two new deep bands at 0.88–1.0 eV and 1.21–1.27 eV were observed, and the intensity of the lower energy band increased with diethylzinc flow rate. The lower energy band was observed even at room temperature, and it is presumed to be related with the saturation of hole concentration.This work was supported by the Ministry of Education through the Interuniversity Semiconductor Research Center ~ISRC 94-E-3142! and Korea Science and Engineering Foundation ~KOSEF 93-01-00-17!. One of the authors ~S.J.K.! would like to acknowledge the support by the Ministry of Education through the Interuniversity Semiconductor Research Center ~ISRC 97-E-3205!

Violet-light spontaneous and stimulated emission from ultrathin In-rich InGaN/GaN multiple quantum wells grown by metalorganic chemical vapor deposition

We investigated the spontaneous and stimulated emission properties of violet-light-emitting ultrathin In-rich InGaN/GaN multiple quantum wells (MQWs) with indium content of 60%-70%. The Stokes shift was smaller than that of In-poor InGaN MQWs, and the emission peak position at 3.196 eV was kept constant with increasing pumping power, indicating negligible quantum confined Stark effect in ultrathin In-rich InGaN MQWs despite of high indium content. Optically pumped stimulated emission performed at room temperature was observed at 3.21 eV, the high-energy side of spontaneous emission, when the pumping power density exceeds ???31 kW/ cm2.open6