502 research outputs found
Modeling left ventricle perfusion in healthy and stenotic conditions
A theoretical fluid mechanical model is proposed for the investigation of myocardial perfusion in healthy and stenotic conditions. The model hinges on Terzaghiâs consolidation theory and reformulates the related unsteady flow equation for the simulation of the swellingâdrainage alternation characterizing the diastolicâsystolic phases. When compared with the outcome of experimental in vivo observations in terms of left ventricle transmural perfusion ratio (T.P.R.), the analytical solution provided by the present study for the time-dependent blood pressure and flow rate across the ventricle wall proves to consistently reproduce the basic mechanisms of both healthy and ischemic perfusion. Therefore, it could constitute a useful interpretative support to improve the comprehension of the basic hemodynamic mechanisms leading to the most common cardiac diseases. Additionally, it could represent the mathematical basis for the application of inverse methods aimed at estimating the characteristic parameters of ischemic perfusion (i.e., location and severity of coronary stenoses) via downstream ventricular measurements, possibly inspiring their assessment via non-invasive myocardial imaging techniques
Theoretical investigation of equilibrium dynamics in braided gravel beds for the preservation of a sustainable fluvial environment
Gravel bars have an important role in the exchange between surface and subsurface waters, in preventing and mitigating riverbank erosion, in allowing the recreational use of rivers, and in preserving fluvial or riparian habitats for species of fishes, invertebrates, plants, and birds. In many cases, gravel bars constitute an important substrate for the establishment and development of ground flora and woody vegetation and guarantee higher plant diversity. A sustainable management of braided rivers should, therefore, ensure their ecological potential and biodiversity by preserving a suitable braiding structure over time. In the present study, we propose an analytical-numerical model for predicting the evolution of gravel bars in conditions of dynamical equilibrium. The model is based on the combination of sediment balance equation and a regression formula relating dimensionless unit bedload rate and stream power. The results highlight the dependence of the evolving sediment particlesâ pattern on the ratio of initial macro-bedforms longitudinal dimension to river width, which determines the gradual transition from advective and highly braiding to diffusive transport regime. Specifically, the tendency to maintain braiding and flow bifurcation is associated with equilibrium average bed profiles and, therefore, equilibrium average stream power characterized by the maximum period that does not exceed transverse channel dimension
POSSIBLE ROLE OF CRY1 AND CRY2 IN ORAL CARCINOGENESIS
Aim. Dysfunction of the circadian clock is involved in tumorigenesis, and altered expression of some clock
genes has been found in cancer patients. It has been shown recently that the occurrence, development, prognosis, and treatment of cancer are closely related to the abnormal expression of certain circadian-clock genes. CRY1 and CRY2 circadian-clock gene plays an important role in the
regulation of many normal hysiological rhythms. This proteins act as light-independent inhibitors of CLOCK-BMAL1 components of the circadian clock. It has been revealed recently that abnormal expression of CRY1 and CRY2 correlate closely with the occurrence and development of many cancers.
However, the expression and significance of this proteins in oral squamous cell carcinoma (OSCC)
remains unknown. The aim of this study was to evaluate the expression levels of CRY1 and CRY2 in oral cancer.
Materials and methods. CRY1 and CRY2 expression in cancerous and peritumoral tissues (when it was
present) from 27 patients with OSCC was detected by immunohistochemistry techniques. Of all samples were received medical records (age, sex, grading, TNM, site of localization of the tumor). Immunohistochemistry was then performed on two sections for each of 27 sample mounted on poly-Llysine-coated glass slides to evaluate respectively the expression of CRY1 and CRY2.Results. In this study, out of the 27 cases, 11 were +/- positive in tumor area for CRY1 (most of which are well (differentiated), while out of 23 cases in which we evaluated the peritumoral tissue present in the
section, 18 were positive. Also in the cases of positive tumor, almost always cytoplasmic, the CRY1 appears to be more strongly positive in dysplastic areas or even more in healthy epithelium, with a negative regulation in the areas most undifferentiated. As for the CRY2, out of the 27 cases analyzed, 17 were positive in the tumor area while about 23 cases in which we evaluated in peritumoral tissue present in the sections, 20 cases were positive. In tumor epithelium were found positivity also medium / high, present in tumors of different degree of differentiation, in some cases in other nuclear or cytoplasmic and nuclear/cytoplasmic, but when present the CRY2 is expressed, in most cases, in a manner similar or more intensely in peritumoral dysplastic epithelium. In the case of CRY2, there were no positivity in healthy epithelium (when present), but only in dysplastic epithelium. In addition, the positivity observed especially
in peritumoral epithelium were present in states intermediate/surface.
Conclusions. In conclusion, abnormal expression levels of CRY1 and CRY2 in OSCC tissue compared to healthy or dysplastic tissue may be related to the process of tumorigenesis. Further research focusing on these genes may, from the perspective of biological rhythms, provide novel ideas and methods for a better understanding of the occurrence and development of tumors, and for treatment of oral cancer
Asymmetric transmission and anomalous refraction in metal nanowires metasurface
Here we investigated the asymmetric transmission and the anomalous refraction introduced by a metasurface of bent gold nanowires. The refraction follows the generalized Snell's law that takes into account the resonant behavior of metallic nanostructures located at the interface between two dielectrics. Measurements performed in the linear optical regime reveal a large sensitivity to the subwavelength features of the gold nanostructures
A Troubling Diagnosis of Verrucous Squamous Cell Carcinoma (âthe Bad Kindâ of Keratosis) and the Need of Clinical and Pathological Correlations: A Review of the Literature with a Case Report
Verrucous carcinoma (also known as Ackerman tumor) is an uncommon exophytic low-grade well-differentiated variant of squamous cell carcinoma. This neoplasm typically involves the oral cavity, larynx, genitalia, skin, and esophagus. It is well known for its locally aggressiveness and for its clinically slow-growing behaviour with minimal metastatic potential. Verrucous carcinoma of oral cavity is so closely aligned with the use of snuff and chewing tobacco that it has been called the âsnuff dipper's cancerâ. Recent studies have proved the role of HPV. The typical clinical presentation of oral verrucous carcinoma has long been known, as its remarkably innocuous appearance and biological behaviour. In this work, we report a review of the scientific literature and describe a troublesome case of oral verrucous cancer
Spatio-Temporal Image-Based Encoded Atlases for EEG Emotion Recognition
Emotion recognition plays an essential role in human-human interaction since it is a key to understanding the emotional states and reactions of human beings when they are subject to events and engagements in everyday life. Moving towards human-computer interaction, the study of emotions becomes fundamental because it is at the basis of the design of advanced systems to support a broad spectrum of application areas, including forensic, rehabilitative, educational, and many others. An effective method for discriminating emotions is based on ElectroEncephaloGraphy (EEG) data analysis, which is used as input for classification systems. Collecting brain signals on several channels and for a wide range of emotions produces cumbersome datasets that are hard to manage, transmit, and use in varied applications. In this context, the paper introduces the EmpaÌtheia system, which explores a different EEG representation by encoding EEG signals into images prior to their classification. In particular, the proposed system extracts spatio-temporal image encodings, or atlases, from EEG data through the Processing and transfeR of Interaction States and Mappings through Image-based eNcoding (PRISMIN) framework, thus obtaining a compact representation of the input signals. The atlases are then classified through the EmpaÌtheia architecture, which comprises branches based on convolutional, recurrent, and transformer models designed and tuned to capture the spatial and temporal aspects of emotions. Extensive experiments were conducted on the Shanghai Jiao Tong University (SJTU) Emotion EEG Dataset (SEED) public dataset, where the proposed system significantly reduced its size while retaining high performance. The results obtained highlight the effectiveness of the proposed approach and suggest new avenues for data representation in emotion recognition from EEG signals
A Novel GAN-Based Anomaly Detection and Localization Method for Aerial Video Surveillance at Low Altitude
The last two decades have seen an incessant growth in the use of Unmanned Aerial Vehicles (UAVs) equipped with HD cameras for developing aerial vision-based systems to support civilian and military tasks, including land monitoring, change detection, and object classification. To perform most of these tasks, the artificial intelligence algorithms usually need to know, a priori, what to look for, identify. or recognize. Actually, in most operational scenarios, such as war zones or post-disaster situations, areas and objects of interest are not decidable a priori since their shape and visual features may have been altered by events or even intentionally disguised (e.g., improvised explosive devices (IEDs)). For these reasons, in recent years, more and more research groups are investigating the design of original anomaly detection methods, which, in short, are focused on detecting samples that differ from the others in terms of visual appearance and occurrences with respect to a given environment. In this paper, we present a novel two-branch Generative Adversarial Network (GAN)-based method for low-altitude RGB aerial video surveillance to detect and localize anomalies. We have chosen to focus on the low-altitude sequences as we are interested in complex operational scenarios where even a small object or device can represent a reason for danger or attention. The proposed model was tested on the UAV Mosaicking and Change Detection (UMCD) dataset, a one-of-a-kind collection of challenging videos whose sequences were acquired between 6 and 15 m above sea level on three types of ground (i.e., urban, dirt, and countryside). Results demonstrated the effectiveness of the model in terms of Area Under the Receiving Operating Curve (AUROC) and Structural Similarity Index (SSIM), achieving an average of 97.2% and 95.7%, respectively, thus suggesting that the system can be deployed in real-world applications
Report of a case of discoid lupus erythematosus localised to the oral cavity: immunofluorescence findings.
Discoid Lupus Erythematosus (DLE) is a chronic disease with a typical cutaneous involvement. This pathology rarely involves mucosa: oral cavity is interested in 20% of DLE patients. We describe a case of oral DLE in a 50-year-old woman with an anamnesis for autoimmune disorders. This study shows the helpful role of immunofluorescence in the diagnosis of autoimmune diseases. The first diagnostic step was the clinical observation of the oral mucosa: the lesion area was erythematous, athrophic and hyperkeratotic. The patient then underwent laboratory examination. We utilized human epithelial cells (Hep-2010) for Indirect Immuno-Fluorescence (IIF). Moreover, the biopsy site for Direct Immuno-Fluorescence (DIF) and histopathological analysis was the untreated oral lesion. IIF detected an increase of Anti-Nuclear Antibody (ANA) and positivity for SSA-RO. By DIF, we observed IgG/IgA/fibrinogen along basal layer. Multiple biopsies reported signs of chronic basal damage. Steroid systemic therapy induced a considerable lesion regression. We suggest the use of immunofluorescence with the integration of further data to improve diagnosis of rare diseases and to establish a suitable therapy
Toll-like receptor 4 expression in the epithelium of inflammatory periapical lesions. An immunohistochemical study
Toll-like receptors (TLR) are essential for the innate immune response against invading pathogens and have been described in immunocompetent cells of areas affected by periapical disease. Besides initiating the inflammatory response, they also directly regulate epithelial cell proliferation and survival in a variety of settings. This study evaluates the in situ expression of TLR4 in periapical granulomas (PG) and radicular cysts, focusing on the epithelial compartment. Twenty-one periapical cysts (PC) and 10 PG were analyzed; 7 dentigerous non-inflamed follicular cyst (DC) served as control. TLR4 expression was assessed by immunohistochemistry. TLR4 immunoreaction products were detected in the epithelium of all specimens, with a higher percentage of immunostained cells in PG. Although TLR4 overexpression was detected in both PG and PC, there were differences that seemed to be related to the nature of the lesion, since in PG all epithelial cells of strands, islands and trabeculae were strongly immunoreactive for TLR4, whereas in PC only some areas of the basal and suprabasal epithelial layers were immunostained. This staining pattern is consistent with the action of TLR4: in PG it could promote formation of epithelial cell rests of Malassez and in epithelial strands and islands the enhancement of cell survival, proliferation and migration, whereas in PC TLR4 could protect the lining epithelium from extensive apoptosis. These findings go some way towards answering the intriguing question of why many epithelial strands or islands in PG and the lining epithelium of apical cysts regress after non-surgical endodontic therapy, and suggest that TLR4 plays a key role in the pathobiology of the inflammatory process related to periapical disease
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