Classification of masses in ultrasonic B-mode images of the breast tissue using “normalized” parameters of the Nakagami distribution was recently investigated. The technique, however, did not yield ...performances that were comparable to those of an experienced radiologist, and utilized only a single image for tissue characterization. Because radiologists commonly use two to four images of a mass for characterization, a similar procedure is developed here. A simple summation of the normalized Nakagami parameters from two different images of a mass is utilized for classification as benign or malignant. The performance of the normalized Nakagami parameters before and after the summation has been carried out through a receiver operating characteristic (ROC) study. The bootstrap procedure has been utilized to compute the mean and SD of the ROC area,
A
z
, obtained for each parameter. It has been observed that combining normalized Nakagami parameters from two images of the mass may help to improve classification performance over that from utilizing the parameters of just a single image. The performance of this automated parameter-based approach appears to match that of a trained radiologist. (E-mail: pshankar@coe.drexel.edu)
A model for the scattering of ultrasound from breast tissue is proposed. The model is based on the use of non-Rayleigh statistics, specifically the K distribution to describe the backscattered echo ...from the tissue. A multiparameter test based on this model has been designed to characterize the tissue. The data from the B-scan images of the breasts of 6 different patients were analyzed using this model. The results indicate that the non-Rayleigh statistics seem to be useful in characterizing and identifying malignant, benign, and normal tissue regions.< >
Breast cancer diagnosis through ultrasound tissue characterization was studied using receiver operating characteristic (ROC) analysis of combinations of acoustic features, patient age, and ...radiological findings. A feature fusion method was devised that operates even if only partial diagnostic data are available. The ROC methodology uses ordinal dominance theory and bootstrap resampling to evaluate A/sub z/ and confidence intervals in simple as well as paired data analyses. The combined diagnostic feature had an A/sub z/ of 0.96 with a confidence interval of 0.93, 0.99 at a significance level of 0.05. The combined features show statistically significant improvement over prebiopsy radiological findings. These results indicate that ultrasound tissue characterization, in combination with patient record and clinical findings, may greatly reduce the need to perform biopsies of benign breast lesions.
The aim of this study was to characterize the local distribution and organization of the plasma membrane NADPH-oxidase (NOX) in human haematopoietic stem cell (HSC) by means of the fluorescence ...scanning near-field optical microscopy approach. The presence of NOX in haematopoietic stem cells is thought to have a functional role as O₂ sensor and/or as low-level reactive oxygen species (ROS) producer to be used as redox messenger for controlling cell growth and differentiation. Given the harmful potential of ROS, a fine-tuning of NOX activity is needed. The high resolution imaging of haematopoietic stem cell membrane obtained in this study combined with the immunodetection of NOX indicates for this the occurrence of a cluster-organized structure. These membrane 'rafts'-like micro-compartments may constitute localized protein aggregates whereby the assembly/activation of the NOX components are functionally integrated with upstream factors constituting signal-transduction platforms.
There is a large body of evidence suggesting the connexin gap junction proteins appear to act as tumor suppressors, and their tumor inhibitory effect is usually attributed to their main function of ...cell coupling through gap junctions. However, some cancer cells (e.g. the rat bladder carcinoma BC31 cell line) are cell-cell communication proficient. Using specific site-directed mutagenesis in the third membrane-spanning (3M) domain of connexin43 (Cx43), we abolished the intrinsic gap junction intercellular communication (GJIC) in BC31 cells either by closing the gap junctional channels or by disruption of the transport of connexin complexes to the lateral membrane. Clones of BC31 cells transfected with a dominant negative Cx43 mutant giving rise to gap junctional channels, permeable only for a small tracer (neurobiotin), displayed accelerated growth rate in vivo, showing the critical role of selective gap junctional permeability in the regulation of cell growth in vivo. The use of other dominant-negative mutants of Cx43 also suggested that the effect of impaired communication on the tumorigenicity of cancer cells depends on the subcellular location of connexin. Inhibition of intrinsic GJIC in BC31 cells by sequestering of Cx protein inside the cytoplasm, due to expression of dominant-negative transport-deficient Cx43 mutants, did not significantly enhance the growth of transfectants in nude mice, but occasionally slightly retarded it. In contrast, augmentation of GJIC in BC31 cells by forced expression of wild-type Cx43, or a communication-silent mutant, fully suppressed tumorigenicity of these cells. Overall, these results show that cell coupling is a strong, but not the sole, mechanism by which Cx suppresses growth of tumorigenic cells in vivo; a GJIC-independent activity of Cx proteins should be considered as another strong tumor-suppressive factor.
The paracrine signaling pathways for the crosstalk between pericytes and endothelial cells are essential for the coordination of cell responses to challenges such as hypoxia in both healthy ...individuals and pathological conditions. Ischemia-reperfusion injury (IRI), one of the causes of cellular dysfunction and death, is associated with increased expression of genes involved in cellular adaptation to a hypoxic environment. Hypoxic inducible factors (HIFs) have a central role in the response to processes initiated by IRI not only linked to erythropoietin production but also because of their participation in inflammation, angiogenesis, metabolic adaptation, and fibrosis. While pericytes have an essential physiological function in erythropoietin production, a lesser-known role of HIF stabilization during IRI is that pericytes' HIF expression could influence vascular remodeling, cell loss and organ fibrosis. Better knowledge of mechanisms that control functions and consequences of HIF stabilization in pericytes beyond erythropoietin production is advisable for the development of therapeutic strategies to influence disease progression and improve treatments. Thus, in this review, we discuss the dual roles-for good or bad-of HIF stabilization during IRI, focusing on pericytes, and consequences in particular for the kidneys.
The Divertor Tokamak Test (DTT) is a new, super-conducting device, being constructed in Frascati, Italy. DTT will be capable of plasma operations at high density and high heating power, in conditions ...relevant to address the power exhaust issue in support of ITER operation and DEMO design. DTT foresees the installation of a mix of auxiliary heating systems to couple up to 45 MW to the plasma, including Neutral Beam Injection (NBI). The neutral beam injector is currently being designed, aiming at delivering tangentially to the plasma neutral particles at energy of 510 keV, with a total power of ∼10 MW.
In the present work, we apply for the first time the orbit-following Monte Carlo code ASCOT to DTT, in order to analyse with more details the interaction of the high-energy beam, described in real geometry beamlet by beamlet, and the plasma. The results of the simulation give an insight of the behaviour of beam energetic particles in DTT. Thanks to the flexibility of DTT, different plasmas can be generated, e.g. in terms of plasma shape due to different divertor concepts. We present the comparison of two cases with different plasma vertical positions and we analyse the effect on beam absorption in the plasma. We then present a sensitivity scan on plasma density, to verify the coupling of beam power at densities lower than the reference target scenario. These investigations are crucial to provide feedback and suggestions to DTT design and to assess the beam fast ion physics for plasma scenario developments.
Mutations in the SARS-CoV-2 genome can alter the virus' fitness, leading to the emergence of variants of concern (VOC). In Brazil, the Gamma variant dominated the pandemic in the first half of 2021, ...and from June onwards, the first cases of Delta infection were documented. Here, we investigate the introduction and dispersal of the Delta variant in the RS state by sequencing 1077 SARS-CoV-2-positive samples from June to October 2021. Of these samples, 34.7% were identified as Gamma and 65.3% as Delta. Notably, 99.2% of Delta sequences were clustered within the 21J lineage, forming a significant Brazilian clade. The estimated clock rate was 5.97 × 10
substitutions per site per year. The Delta variant was first reported on 17 June in the Vinhedos Basalto microregion and rapidly spread, accounting for over 70% of cases within nine weeks. Despite this, the number of cases and deaths remained stable, possibly due to vaccination, prior infections, and the continued mandatory mask use. In conclusion, our study provides insights into the Delta variant circulating in the RS state, highlighting the importance of genomic surveillance for monitoring viral evolution, even when the impact of new variants may be less severe in a given region.
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