Ultra Dense Edge Caching Networks With Arbitrary User Spatial Density

Cache-enabled small cells can be an effective solution to deliver contents to mobile users with much lower power and latency. While the trend for getting smaller and denser cells is clear, interference will soon become unmanageable and an obstacle when the number of content requests is massive. Moreover, content request is seldom a spatially homogeneous process due to physical impediments (e.g., buidings) and social activities, which makes resource allocation for content delivery more challenging. In this paper, we consider an ultra-dense network (UDN) in which content requests are served by cache-enabled access nodes which can either be active for delivering contents to users, or inactive to reduce interference and network energy consumption. Our aim is to devise an approach that can locally adapt the caching node density and content caching probabilities to accommodate any arbitrary user density and content request for maximizing the network’s successful content delivery probability (SCDP). With a non-homogeneous spatial distribution for user equipments (UEs), we find that user-load, a parameter at the access node, plays a major role in the overall optimization. Simulation results illustrate that the proposed method can obtain superior performance against the considered benchmarks, with up to 150-160% increase, and our optimized solutions effectively adapt to the spatial-dependent user density

Endosonography in gastric lymphoma and large gastric folds

To establish a correct preoperative differential diagnosis between gastric lymphoma and cancer is essential but can be difficult as endoscopic biopsies can sometimes provide a low diagnostic yield. By EUS, infiltrative carcinoma tends to show a vertical growth in the gastric wall, while lymphoma tends to show mainly a horizontal extension. EUS provides an accurate staging of gastric lymphoma, showing the exact level of infiltration and the presence of perigastric lymph nodes, thus the physician can obtain an accurate prognosis for each patient and select the best form of treatment accordingly. The response to chemoradiotherapy can also be investigated very accurately by EUS. Large gastric folds are seen in a great number of benign and malignant conditions. Diagnosis represents a clinical challenge because etiology may be extremely varied and standard biopsies are often inconclusive. Different diseases show different levels of infiltration of the gastric wall, thus a characteristic echo-pattern helps for the differential diagnosis. Endosonography, used always in combination with biopsy, allows to rule out malignancies and to select the most appropriate treatment for each patient (medical or surgical). (C) 2000 Elsevier Science Ireland Ltd

Single-band mucosectomy for granular cell tumor of the esophagus: safe and easy technique

Background: Mucosectomy involves resection of a digestive wall fragment that frequently removes a part or even all of the submucosal mass. The single-band mucosectomy technique was used to remove a granular cell tumor (GCT) of the esophagus. Only 3% of GCTs, which are relatively uncommon neoplasms, arise in the esophagus. Ultrasonography has allowed for more frequent recognition and better definition of this disease. Until recently, surgical resection of the esophagus has been the only treatment alternative to endoscopic surveillance. Endoscopic techniques such as mucosal resection (EMR), laser, and argon plasma have been proposed as safe and effective alternatives to surgery. However, to date, only a few reports of these endoscopic techniques have been published. This study aimed to evaluate the safety and feasibility of single-band mucosectomy for removing a GCT of the esophagus. Methods: Six patients (1 man and 5 women; mean age, 45 years) with a GCT were studied between January 2000 and May 2004. They underwent EMR after endoscopic ultrasonography. Results: The EMR was performed with a diathermic loop after injection of saline solution into the esophageal wall. Only one session was necessary for removal of the tumor from all 6 patients, and no complication was observed. During a mean clinical endoscopic follow-up period of 36 months, no recurrences, scars, or stenoses were observed. Conclusions: These findings show EMR to be a safe and effective technique that allows complete removal of GCTs. Furthermore, this technique provides tissue for a definitive pathologic diagnosis, which laser and argon plasma do not provide. We recommend EMR as the treatment of choice for GCTs after an accurate ultrasonographic evaluation

Endoscopic ultrasound: accuracy in staging superficial carcinomas of the esophagus

Abstract: Background. Endoscopic procedures may represent an alternative to esophagectomy for superficial neoplasms of the esophagus (T1m/T1sm), but they are considered curative only in case of no lymph node involvement. Endoscopic ultrasound (EUS) is the most accurate method to define both T and N staging of esophageal carcinoma. Aims of the study were to assess the staging accuracy of EUS in superficial lesions (T1m and T1sm) of patients who were candidates for esophagectomy or local endoscopic resection and to establish which variables (site of neoplasm, histologic type, macroscopic appearance) can affect the accuracy of EUS in distinguishing between T1m and T1sm lesions. Methods. The study population consisted of 55 patients with superficial carcinoma of the esophagus who underwent EUS (October 2002 to January 2007). Endoscopic ultrasound features were compared with findings from surgical specimens or samples obtained at mucosectomy. Results. There were 33 patients with adenocarcinoma (60%), which developed on Barrett's esophagus in 27 cases, 21 patients (38%) with squamous cell carcinoma, and 1 (2%) with lymphoepithelial-like carcinoma. All lesions were confirmed as T1 on pathology. Of the 22 (40%) T1m lesions on EUS, 19 (86%) were confirmed as T1m on pathology; of the 33 T1sm on EUS, 22 (66%) were confirmed as T1sm. Positive predictive value of EUS for invasion of the submucosa was 67%, negative predictive value 86%, sensitivity 88%, specificity 63%, and diagnostic accuracy 75%. The accuracy of EUS in evaluating lymph node metastases was 71%, with a negative predictive value of 84%. Endoscopic ultrasound accuracy in differentiating mucosal from submucosal lesions increased from the lower esophagus or gastroesophageal junction to the mid and upper esophagus (71%, 76%, and 100%, respectively; not significant). As for the histologic type, accuracy was 70% for adenocarcinoma and 81% for squamous cell carcinoma, (not significant); for lesions detected as type 0-IIa (13 patients), accuracy was 100%; for type 0-I lesions (23 patients), accuracy was 70% (p = 0.03). Conclusions. Despite difficulties in differentiating mucosal from submucosal lesions, even with 20-MHz miniprobes, EUS remains an extremely valuable tool when nonsurgical treatments are considered. Its staging accuracy depends on site and macroscopic appearance of the neoplasm

Operative endosonography

New interventional applications have recently been added to the endosonographic methods, thanks to the improvement of linear scanning devices. This particular orientation of ultrasonic waves, unlike the traditional radial scanning, allows the use of new accessories to make cytologic and hystologic samples under endosonographic guidance (fine needle aspiration) and new therapeutic approaches. Let's mention first the fine needle aspiration of deep intramural GI lesions, of potentially pathologic lymph nodes, of pancreatic, hepatic or adrenal gland masses. Regarding therapeutic applications it's worth considering the drainage of pancreatic pseudocysts, the botulinum toxin injection for achalasia and the celiac plexus neurolysis under endosonographic control. When handled by experts, these techniques have been shown to be effective, safe and fast in a high percentage of cases, and they allow a noticeable cost reduction compared to more invasive procedures

Cancer of the esophagus - Endoscopic ultrasound: Selection for cure

Several treatment options are available to treat esophageal cancer. Ideally, treatment should be individualized, based on the projected treatment outcome for that individual. Accurate staging of the extent of the disease at the time of diagnosis offers the most rational attempt at stratifying patients into categories that can be used to affect treatment choices. Endoscopic ultrasonography (EUS) is the most accurate nonoperative technique for determining the depth of tumour infiltration and thus is accurate in predicting which patients will be able to undergo complete resection. EUS is also being used for tumour staging in order to guide treatment decisions in patients with esophageal cancer

Harnessing distress to boost growth in frontline healthcare workers during COVID-19 pandemic: the protective role of resilience, emotion regulation and social support

An abstract is not available for this content

Endoscopic diagnosis and classification of varices of the gastro-intestinal tract

Quand s'instaure un état d'hypertension portale, des circulations collatérales entre le système porte et le système cave se forment ou s'ouvrent. Du point de vue clinique, les plus importantes sont celles qui impliquent le secteur gastro-intestinal, parce qu'elles peuvent provoquer la dilatation du plexus sous-muqueux avec formation de varices endoluminales. Les varices peuvent se trouver sur tous les secteurs du tractus gastro-intestinal (oesophage, estomac, duodénum, iléon, côlon, rectum), mais les varices gastro-œsophagiennes s'observent plus fréquemment et en cas de rupture, elles peuvent provoquer de graves hémorragies. L'hémorragie de varices oesophagiennes représente encore aujourd'hui une des plus graves complications de la cirrhose hépatique et un défi toujours renouvelé pour l'endoscopiste, Malgré l'introduction de nouveaux moyens diagnostiques et de nouvelles thérapies, la mortalité au premier épisode de saignement reste encore très élevée (30 %-40 %). Ceci est lié non seulement à l'entité de l'hémorragie et à la vitesse de son contrôle mais également au stade d'insuffisance hépatique et à l'apparition de complications cardio-pulmonaires, rénales, infectieuses et surtout hémorragiques. L'examen endoscopique, s'il est conduit de manière correcte, représente la meilleure technique pour le diagnostic, la classification et la thérapie aussi bien en première intention qu'en urgence