In recent years, reliability has become one critical issue in the designs of flash file systems due to the growing unreliability of advanced flash-memory chips. In this paper, a version-based ...strategy with optimal space utilization is proposed to maintain the consistency among page versions of a file for potential recovery needs with the considerations of the write constraints of multi-level-cell flash memory. A series of experiments was conducted to show that the proposed strategy could improve the reliability of flash file systems with limited management and space overheads.
With selectively-deposited tungsten film grown on source/drain regions, the parasitic source/drain resistance of thin-channel polycrystalline silicon (poly-Si) thin film transistors can be greatly ...reduced, leading to the improvement of device driving ability. After extracting the parasitic resistance from characteristics of devices with different channel length, the influences of parasitic resistance on device performances were discussed. A physically-based equation containing the parasitic resistance effects was derived to explain the behavior of linear transconductance under high gate voltage. Good agreements were found between calculated and measured data for both the thin-channel devices with or without tungsten-clad source/drain structure.
Predicting the pH-activities of residues in proteins is an important problem in enzyme engineering and protein design. A novel predictor called 'Pred-pK sub(a)' was developed based on the ...physicochemical properties of amino acids and protein 3D structure. The Pred-pK sub(a) approach considers the influence of all other residues of the protein to predict the pK sub(a) value of an ionizable residue. An empirical equation was formulated, in which the pK sub(a) value was a distance-dependent function of physicochemical parameters of 20 amino acid types, describing their electrostatic and van der Waals interaction, as well as the effects of hydrogen bonds and solvation. Two sets of coefficients, {a sub(a)} and {b sub(l)}, were used in the predictor: {a sub(a)} is the weight factors of 20 amino acid types and {b sub(l)} is the weight factors of physicochemical properties of amino acids. An iterative double least square procedure was proposed to solve the two sets of weight factors alternately and iteratively in a training set. The two coefficient sets {a sub(a)} and {b sub(l)} thus obtained were used to predict the pK sub(a) values of residues in a protein. The average predictive error is c0.6 pH in less than a minute in common personal computer.
Renewal of the intestinal epithelium occurs approximately every week and requires a careful balance between cell proliferation and differentiation to maintain proper lineage ratios and support ...absorptive, secretory, and barrier functions. We review models used to study the mechanisms by which intestinal stem cells (ISCs) fuel the rapid turnover of the epithelium during homeostasis and might support epithelial regeneration after injury. In anatomically defined zones of the crypt stem cell niche, phenotypically distinct active and reserve ISC populations are believed to support homeostatic epithelial renewal and injury-induced regeneration, respectively. However, other cell types previously thought to be committed to differentiated states might also have ISC activity and participate in regeneration. Efforts are underway to reconcile the proposed relatively strict hierarchical relationships between reserve and active ISC pools and their differentiated progeny; findings from models provide evidence for phenotypic plasticity that is common among many if not all crypt-resident intestinal epithelial cells. We discuss the challenges to consensus on ISC nomenclature, technical considerations, and limitations inherent to methodologies used to define reserve ISCs, and the need for standardized metrics to quantify and compare the relative contributions of different epithelial cell types to homeostatic turnover and post-injury regeneration. Increasing our understanding of the high-resolution genetic and epigenetic mechanisms that regulate reserve ISC function and cell plasticity will help refine these models and could affect approaches to promote tissue regeneration after intestinal injury.
A local image descriptor robust to the common photometric transformations (blur, illumination, noise, and JPEG compression) and geometric transformations (rotation, scaling, translation, and ...viewpoint) is crucial to many image understanding and computer vision applications. In this paper, the representation and matching power of region descriptors are to be evaluated. A common set of elliptical interest regions is used to evaluate the performance. The elliptical regions are further normalized to be circular with a fixed size. The normalized circular regions will become affine invariant up to a rotational ambiguity. Here, a new distinctive image descriptor to represent the normalized region is proposed, which primarily comprises the Zernike moment (ZM) phase information. An accurate and robust estimation of the rotation angle between a pair of normalized regions is then described and used to measure the similarity between two matching regions. The discriminative power of the new ZM phase descriptor is compared with five major existing region descriptors (SIFT, GLOH, PCA-SIFT, complex moments, and steerable filters) based on the precision-recall criterion. The experimental results, involving more than 15 million region pairs, indicate the proposed ZM phase descriptor has, generally speaking, the best performance under the common photometric and geometric transformations. Both quantitative and qualitative analyses on the descriptor performances are given to account for the performance discrepancy. First, the key factor for its striking performance is due to the fact that the ZM phase has accurate estimation accuracy of the rotation angle between two matching regions. Second, the feature dimensionality and feature orthogonality also affect the descriptor performance. Third, the ZM phase is more robust under the nonuniform image intensity fluctuation. Finally, a time complexity analysis is provided.
Surprisingly, it is estimated that about half of type 2 diabetics remain undetected. The possible causes may be partly attributable to people with normal fasting plasma glucose (FPG) but abnormal ...postprandial hyperglycemia. We attempted to develop an effective predictive model by using the metabolic syndrome (MeS) components as parameters to identify such persons.
All participants received a standard 75-g oral glucose tolerance test, which showed that 106 had normal glucose tolerance, 61 had impaired glucose tolerance, and 6 had diabetes-on-isolated postchallenge hyperglycemia. We tested five models, which included various MeS components. Model 0: FPG; Model 1 (clinical history model): family history (FH), FPG, age and sex; Model 2 (MeS model): Model 1 plus triglycerides, high-density lipoprotein cholesterol, body mass index, systolic blood pressure and diastolic blood pressure; Model 3: Model 2 plus fasting plasma insulin (FPI); Model 4: Model 3 plus homeostasis model assessment of insulin resistance. A receiver-operating characteristic (ROC) curve was used to determine the predictive discrimination of these models.
The area under the ROC curve of the Model 0 was significantly larger than the area under the diagonal reference line. All the other 4 models had a larger area under the ROC curve than Model 0. Considering the simplicity and lower cost of Model 2, it would be the best model to use. Nevertheless, Model 3 had the largest area under the ROC curve.
We demonstrated that Model 2 and 3 have a significantly better predictive discrimination to identify persons with normal FPG at high risk for glucose intolerance.
Pro-inflammatory cytokine TNFα plays critical roles in promoting malignant cell proliferation, angiogenesis, and tumor metastasis in many cancers. However, the mechanism of TNFα-mediated tumor ...development remains unclear. Here, we show that IKKα, an important downstream kinase of TNFα, interacts with and phosphorylates FOXA2 at S107/ S111, thereby suppressing FOXA2 transactivation activity, leading to decreased NUMB expression and further activates the downstream NOTCH pathway and promotes cell proliferation and tumorigenesis. Moreover, we found that levels of IKKα, pFOXA2 (S107/111), and activated NOTCH1 were significantly higher in hepatocellular carcinoma tumors than in normal liver tissues and that pFOXA2 (S107/111) expression was positively correlated with IKKα and activated NOTCH1 expression in tumor tissues. Therefore, dysregulation of NUMB-mediated suppression of
NOTCH1
by TNFα/IKKα-associated FOXA2 inhibition likely contributes to inflammation-mediated cancer pathogenesis. Here, we report TNFα/IKKα/FOXA2/NUMB/NOTCH1 pathway that is critical for inflammation-mediated tumorigenesis and may provide a target for clinical intervention in human cancer.
A complex of incipient species with different degrees of morphological or ecological differentiation provides an ideal model for studying species divergence. We examined the phylogeography and the ...evolutionary history of the Rhododendron pseudochrysanthum s. l. Systematic inconsistency was detected between gene genealogies of the cpDNA and nrDNA. Rooted at R. hyperythrum and R. formosana, both trees lacked reciprocal monophyly for all members of the complex. For R. pseudochrysanthum s.l., the spatial distribution of the cpDNA had a noteworthy pattern showing high genetic differentiation (F.sub.ST = 0.56-0.72) between populations in the Yushan Mountain Range and populations of the other mountain ranges. Both incomplete lineage sorting and interspecific hybridization/introgression may have contributed to the lack of monophyly among R. hyperythrum, R. formosana and R. pseudochrysanthum s.l. Independent colonizations, plus low capabilities of seed dispersal in current environments, may have resulted in the genetic differentiation between populations of different mountain ranges. At the population level, the populations of Central, and Sheishan Mountains may have undergone postglacial demographic expansion, while populations of the Yushan Mountain Range are likely to have remained stable ever since the colonization. In contrast, the single population of the Alishan Mountain Range with a fixed cpDNA haplotype may have experienced bottleneck/founder's events.
In addition to the target echo, the signal environment of the secondary surveillance radar (SSR) also includes environmental echo and noise interference, which greatly affect the correct decoding of ...the response signal. Nowadays, the processing of secondary radar response signals basically uses traditional signal processing methods, and there are few methods for denoising using deep learning neural networks. This paper proposes a secondary radar signal processing method based on the deep residual separable neural network (DRS-Net), which can effectively extract the deep features of the secondary radar signal and predict the original response signal. The core of the network is based on the deep separable convolutional neural network, and the deep residual connection structure can effectively learn the deep features of the signal. We conducted a lot of experiments and verifications using secondary radar response signals with different signal-to-noise ratio noise. The experimental results show that the method has high denoising performance in the normal radar operating environment and can accurately predict secondary radar response signals. When the signal-to-noise ratio is 5dB, the strict accuracy rate can reach 94%. When the signal-to-noise ratio is higher than 10dB, the strict accuracy rate has reached 99.95%.
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