Geometric nonlinear diffusion filter and its application to X-ray imaging

<p>Abstract</p> <p>Background</p> <p>Denoising with edge preservation is very important in digital x-ray imaging since it may allow us to reduce x-ray dose in human subjects without noticeable degradation of the image quality. In denoising filter design for x-ray imaging, edge preservation as well as noise reduction is of great concern not to lose detailed spatial information for accurate diagnosis. In addition to this, fast computation is also important since digital x-ray images are mostly comprised of large sized matrices.</p> <p>Methods</p> <p>We have developed a new denoising filter based on the nonlinear diffusion filter model. Rather than employing four directional gradients around the pixel of interest, we use geometric parameters derived from the local pixel intensity distribution in calculating the diffusion coefficients in the horizontal and vertical directions. We have tested the filter performance, including edge preservation and noise reduction, using low dose digital radiography and micro-CT images.</p> <p>Results</p> <p>The proposed denoising filter shows performance similar to those of nonlinear anisotropic diffusion filters (ADFs), one Perona-Malik ADF and the other Weickert's ADF in terms of edge preservation and noise reduction. However, the computation time has been greatly reduced.</p> <p>Conclusions</p> <p>We expect the proposed denoising filter can be greatly used for fast noise reduction particularly in low-dose x-ray imaging.</p

Reduction of metabolic waste products, ammonia and lactate, through the coupling of GS selection and LDH-A down-regulation in CHO cells

The cultivation of Chinese hamster ovary (CHO) cells for the production of therapeutic proteins inevitably accompanies the production of metabolic wastes, mostly ammonia and lactate. Ammonia alters cell growth, productivity and the glycosylation patterns of proteins, and lactate acidifies culture media, having negative effects on cell culture. A stable CHO cell line should be established for the manufacturing process of therapeutic proteins, and the development of stable cell lines is usually based on two expression systems: the dihydrofolate reductase (DHFR) system and the glutamine synthetase (GS) system. Compared to the DHFR system, the GS system produces a reduced level of ammonia because the GS protein uses ammonia to produce glutamine. In order to overcome the lactate accumulation problem, down-regulation of the lactate-producing enzyme, lactate dehydrogenase-A (LDH-A), has been shown to be effective. Engineering of the LDH-A gene has been applied for several CHO cell lines with the DHFR system, but there has been no trial which couples the ammonia reduction from the GS system and lactate reduction through cell engineering. In the present study, the GS system was used for the expression of therapeutic antibody in CHO cells, thereby reducing ammonia in the culture media. In addition, the LDH-A gene was down-regulated with shRNA to reduce lactate production. The antibody-producing cell line produces a reduced level of ammonia compared to the host cell line due to the over-expression of the GS protein. The down–regulation of the LDH-A gene in the antibody-producing cell line not only reduces the level of lactate but also further reduces the level of ammonia, accomplishing complete waste reduction. LDH-A down-regulation was also applied to the host cell lines of the GS system – the CHO-K1 cell line and the GS deficient CHO-K1 cell line. However, LDH-A down-regulated host cells could not survive the pool-selection process. Given that the GS system uses a glutamine-depleted condition as a form of selection pressure, enhanced glycolysis is inevitable and the down-regulation of LDH-A appears to hinder metabolic changes. Taken together, the application of LDH-A down-regulation in the producing cell line of the GS system successfully reduced both ammonia and lactate levels. However, LDH-A engineering could not be applied to the host cell lines because it inhibits the selection process of the GS system

Investigation of thermal resistance and power consumption in Ga-doped indium oxide (In2O3) nanowire phase change random access memory

The resistance stability and thermal resistance of phase change memory devices using similar to 40 nm diameter Ga-doped In2O3 nanowires (Ga:In2O3 NW) with different Ga-doping concentrations have been investigated. The estimated resistance stability (R(t)/R-0 ratio) improves with higher Ga concentration and is dependent on annealing temperature. The extracted thermal resistance (R-th) increases with higher Ga-concentration and thus the power consumption can be reduced by similar to 90% for the 11.5% Ga: In2O3 NW, compared to the 2.1% Ga: In2O3 NW. The excellent characteristics of Ga-doped In2O3 nanowire devices offer an avenue to develop low power and reliable phase change random access memory applications. (C) 2014 AIP Publishing LLC.X113sciescopu

A Novel Mutation in the XLRS1 Gene in a Korean Family with X-linked Retinoschisis

Purpose: To report a novel missense mutation in the XLRS1 gene in a Korean family with X-linked retinoschisis. Methods: Observation case report of a family with a proband with X-linked retinoschisis underwent complete ophthalmologic examination. Genomic DNA was excluded from the family's blood and all exons of the XLRS1 gene were amplified by polymerase chain reaction and analyzed using a direct sequencing method. Results: A novel Leu103Phe missense mutation was identified. Conclusions: A novel Leu103Phe mutation is an additional missense mutation which is responsible for the pathogenesis of X-linked retinoschisis.ope

Influence of the range of data on the performance of ANN- and SVM- based time series models for reproducing groundwater level observations

In the present study, we designed time series models for predicting groundwater level fluctuations using an artificial neural network (ANN) and a support vector machine (SVM). To estimate the model sensitivity to the range of data set for the model building, numerical tests were conducted using hourly measured groundwater level data at a coastal aquifer of Jeju Island in South Korea. The model performance of the two models is similar and acceptable when the range of input variable lies within the data set for the model building. However, when the range of input variables is beyond it, both the models showed abnormal prediction results: an oscillation for the ANN model and a constant value for SVM. The result of the numerical tests indicates that it is necessary to obtain various types of input and output variables and assign them to the model building process for the success of design time series models of groundwater level prediction

Replication of the genetic effects of IFN regulatory factor 5 (IRF5) on systemic lupus erythematosus in a Korean population

Recently, two studies provided convincing evidence that IFN regulatory factor 5 (IRF5) gene polymorphisms are significantly associated with systemic lupus erythematosus (SLE) in several white populations. To replicate the association with SLE in an Asian population, we examined the genetic effects in our SLE cohort from a Korean population. A total of 1,565 subjects, composed of 593 cases and 972 controls, were genotyped using the TaqMan® (Applied Biosystems, Foster City, CA, USA) method. The genetic effects of polymorphisms on the risk of SLE were evaluated using χ2 tests and a Mantel–Haenszel meta-analysis. Statistical analysis revealed results in the Korean population were similar to the previous reports from white populations. The rs2004640 T allele had a higher frequency in SLE cases (0.385) than controls (0.321; odds ratio (OR) = 1.32, P = 0.0003). In combined analysis, including all seven independent cohorts from the three studies so far, robust and consistent associations of the rs2004640 T allele with SLE were observed. The estimate of risk was OR = 1.44 (range, 1.34–1.55), with an overall P = 1.85 × 10-23 for the rs2004640 T allele. The haplotype (rs2004640T–rs2280714T) involved in both the alternative splice donor site and the elevated expression of IRF5 also had a highly significant association with SLE (pooled, P = 2.11 × 10-16). Our results indicate that the genetic effect on the risk of SLE mediated by IRF5 variants can be generally accepted in both white and Asian populations

Effect of Long-Term Dietary Arginyl-Fructose (AF) on Hyperglycemia and HbA1c in Diabetic db/db Mice

We have previously reported that Amadori compounds exert anti-diabetic effects by lowering sucrose-induced hyperglycemia in normal Sprague-Dawley rats. In the present study we extended our recent findings to evaluate whether α-glucosidase inhibitor arginyl-fructose (AF) lowers blood glucose level in diabetic db/db mice, a genetic model for type 2 diabetes. The db/db mice were randomly assigned to high-carbohydrate diets (66.1% corn starch) with and without AF (4% in the diet) for 6 weeks. Changes in body weight, blood glucose level, and food intake were measured daily for 42 days. Dietary supplementation of AF resulted in a significant decrease of blood glucose level (p \u3c 0.001) and body weight (p \u3c 0.001). The level of HbA1c, a better indicator of plasma glucose concentration over prolonged periods of time, was also significantly decreased for 6-week period (p \u3c 0.001). Dietary treatment of acarbose® (0.04% in diet), a positive control, also significantly alleviated the level of blood glucose, HbA1c, and body weight. These results indicate that AF Maillard reaction product improves postprandial hyperglycemia by suppressing glucose absorption as well as decreasing HbA1c level

Effect of Long-Term Dietary Arginyl-Fructose (AF) on Hyperglycemia and HbA1c in Diabetic \u3cem\u3edb/db\u3c/em\u3e Mice

We have previously reported that Amadori compounds exert anti-diabetic effects by lowering sucrose-induced hyperglycemia in normal Sprague-Dawley rats. In the present study we extended our recent findings to evaluate whether α-glucosidase inhibitor arginyl-fructose (AF) lowers blood glucose level in diabetic db/db mice, a genetic model for type 2 diabetes. The db/db mice were randomly assigned to high-carbohydrate diets (66.1% corn starch) with and without AF (4% in the diet) for 6 weeks. Changes in body weight, blood glucose level, and food intake were measured daily for 42 days. Dietary supplementation of AF resulted in a significant decrease of blood glucose level (p \u3c 0.001) and body weight (p \u3c 0.001). The level of HbA1c, a better indicator of plasma glucose concentration over prolonged periods of time, was also significantly decreased for 6-week period (p \u3c 0.001). Dietary treatment of acarbose® (0.04% in diet), a positive control, also significantly alleviated the level of blood glucose, HbA1c, and body weight. These results indicate that AF Maillard reaction product improves postprandial hyperglycemia by suppressing glucose absorption as well as decreasing HbA1c level