Dynamic vs Oblivious Routing in Network Design

Consider the robust network design problem of finding a minimum cost network with enough capacity to route all traffic demand matrices in a given polytope. We investigate the impact of different routing models in this robust setting: in particular, we compare \emph{oblivious} routing, where the routing between each terminal pair must be fixed in advance, to \emph{dynamic} routing, where routings may depend arbitrarily on the current demand. Our main result is a construction that shows that the optimal cost of such a network based on oblivious routing (fractional or integral) may be a factor of \BigOmega(\log{n}) more than the cost required when using dynamic routing. This is true even in the important special case of the asymmetric hose model. This answers a question in \cite{chekurisurvey07}, and is tight up to constant factors. Our proof technique builds on a connection between expander graphs and robust design for single-sink traffic patterns \cite{ChekuriHardness07}

Gastrointestinal Endoscopy in the Era of COVID-19

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), which led to a worldwide pandemic that started in early 2020. Healthcare systems across the world encountered an unprecedented surge of COVID-19 patients resulting in more than half a million deaths globally. COVID-19 has affected multiple sub-specialties and procedure-related fields, including gastroenterology. Gastrointestinal (GI) endoscopy centers are specialized units where thousands of endoscopies are performed annually. A significant proportion of these procedures are affected due to the national and regional lockdowns across the globe. To adapt to this rapidly evolving situation, endoscopy centers have undergone significant changes and have taken unprecedented precautions to avoid the transmission of the virus. However, endoscopy centers are going through financial strain due to a reduction in the number of procedures from lockdowns and fear of virus transmission. Theoretically, endoscopies could add to the disease transmission as SARS-CoV-2 has shown to be present in the GI secretions. Multiple precautions such as mandatory use of face masks, safe distancing, use of barriers between the endoscopists and patients, negative pressure rooms, extended use of personal protective equipment, and volume reduction have been taken to decrease the risk of disease transmission by these centers. Moreover, pre-endoscopy COVID-19 testing has now become the norm. In this review, we highlight the significant changes assumed by the endoscopy center. Furthermore, we discuss cost-related concerns of pre-endoscopy COVID-19 testing, the downtime and delays related to the procedures, and effects of rescheduling. As the pandemic progresses through multiple phases, endoscopy centers should use a dynamic approach to adapt and strive to provide the best patient care

Robust Methods for Real-Time Diabetic Foot Ulcer Detection and Localization on Mobile Devices

Current practice for Diabetic Foot Ulcers (DFU) screening involves detection and localization by podiatrists. Existing automated solutions either focus on segmentation or classification. In this work, we design deep learning methods for real-time DFU localization. To produce a robust deep learning model, we collected an extensive database of 1775 images of DFU. Two medical experts produced the ground truths of this dataset by outlining the region of interest of DFU with an annotator software. Using 5-fold cross-validation, overall, Faster R-CNN with InceptionV2 model using two-tier transfer learning achieved a mean average precision of 91.8%, the speed of 48 ms for inferencing a single image and with a model size of 57.2 MB. To demonstrate the robustness and practicality of our solution to real-time prediction, we evaluated the performance of the models on a NVIDIA Jetson TX2 and a smartphone app. This work demonstrates the capability of deep learning in real-time localization of DFU, which can be further improved with a more extensive dataset

A Review of Clinical Radioprotection and Chemoprotection for Oral Mucositis.

The first tenet of medicine, primum non nocere or first, do no harm , is not always compatible with oncological interventions e.g., chemotherapy, targeted therapy and radiation, since they commonly result in significant toxicities. One of the more frequent and serious treatment-induced toxicities is mucositis and particularly oral mucositis (OM) described as inflammation, atrophy and breakdown of the mucosa or lining of the oral cavity. The sequelae of oral mucositis (OM), which include pain, odynodysphagia, dysgeusia, decreased oral intake and systemic infection, frequently require treatment delays, interruptions and discontinuations that not only negatively impact quality of life but also tumor control and survivorship. One potential strategy to reduce or prevent the development of mucositis, for which no effective therapies exist only best supportive empirical care measures, is the administration of agents referred to as radioprotectors and/or chemoprotectors, which are intended to differentially protect normal but not malignant tissue from cytotoxicity. This limited-scope review briefly summarizes the incidence, pathogenesis, symptoms and impact on patients of OM as well as the background and mechanisms of four clinical stage radioprotectors/chemoprotectors, amifostine, palifermin, GC4419 and RRx-001, with the proven or theoretical potential to minimize the development of mucositis particularly in the treatment of head and neck cancers

COVID-19 and Acute Esophageal Obstruction Management in the Emergency Department: An U.S. multicenter research network propensity-matched analysis

Introduction- The Coronavirus Disease-2019 (COVID-19) caused by the novel SARS-CoV-2 led to significant strain on the Emergency Department (ED) visits worldwide. Multiple stay-at-home orders were issued during the pandemic unless medical treatment was urgently needed . Acute esophageal obstruction (AEO) due to food/ foreign body impaction usually present to the ED, given its severe symptoms. Most esophageal foreign bodies pass through the gastrointestinal (GI) tract uneventfully, and related mortality is very low. Still, most of these patients receive endoscopic interventions (up to 76%). The number of non-urgent endoscopies plummeted sharply during the pandemic to reduce exposure and preserve personal protective equipment. It is unclear if ED visits for AEO and their endoscopic management changed due to the COVID-19 pandemic in the United States (US). Methods- We utilized a federated cloud-based network database named TriNetX, which provides access to electronic medical records from 92 healthcare organizations from the US. The AEO adult patients hospitalized from January 1, 2020, to December 1, 2020, were compared to a similar timeline in 2019 from TriNetX. We used ICD-10 codes for food/foreign body in esophagus, causing other injury acute food impaction (T18.128 A, T18.12), foreign body esophagus (T18.198, T18.1, T18.19, T18.108, T18.108A). Outcomes of the study included utilization rates of esophagogastroduodenoscopy (EGD), esophageal perforation, inpatient hospitalization, and mortality. The outcomes were measured before and after 1:1 propensity matching of the groups based on the baseline demographics and comorbidities. Results- Prevalence of AEO among all ED visits in 2020 were 0.12% (5890 AEO ED visits among 4,672,024 total visits), compared to 0.17% (23,478 AEO ED visits among 14,199,648 total visits) in 2019. There was a small but significant decrease (0.05%) in AEO ED visits from pre-pandemic compared to pandemic times (P<0.01). Patient with AEO had higher prevalence of eosinophilic esophagitis (mean 270 [4.6%] vs. 885 [3.8%], p=0.004) and alcohol-related disorders (mean 465 5 [7.9%] vs. 1659 [7.1%], p=0.03) in 2020 group vs. 2019 group. Patients in the 2020-group had a lower EGD utilization (RR 0.63,95%CI:0.58–0.67, p<0.001) but esophageal perforation (RR 0.87,95%CI:0.41–1.82) and inpatient hospitalization rates (RR 0.92,95%CI:0.79-1.05) did not differ between two groups. Interestingly, during the pandemic, the AEO patients had a lower mortality rate (RR 0.23, 95%CI:0.17–0.31, p<0.001) than in 2019. Conclusion With the advent of COVID-19, multiple stay-at-home orders were issued in the US, with widespread healthcare services and utilization disruption. Patients have expressed concerns about visiting healthcare facilities due to the potential of the spread of SARS-CoV-2 . Many GI societies also recommended deferring elective procedures. This was due to a concern for potential transmission of the virus from aerosolization of GI secretions and judicious use of PPE, which resulted in an overall reduction in the number of endoscopies during the pandemic. Our study shows a small reduction (0.05%) of AEO ED visits in 2020 compared to 2019. However, EGD utilization plummeted to 63% for AEO in 2020. If this is due to spontaneous resolution of the food impaction or reduced presentations to the ED needs to be studied prospectively

Prevalence, Mechanisms, and Implications of Gastrointestinal Symptoms in COVID-19

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. The infection started as an outbreak of pneumonia-like symptoms in Wuhan, China. Within a few weeks, it spread across the entire globe resulting in millions of cases and thousands of deaths. While respiratory symptoms and complications are well-defined and can be severe, non-respiratory symptoms of COVID-19 are increasingly being recognized. Gastrointestinal manifestations such as nausea, vomiting, diarrhea, and abdominal pain have been added to the list of common COVID-19 symptoms. Their prevalence has been increasing, probably due to increased recognition and experience with the pandemic. Furthermore, diarrhea and stool testing may change prevalence and transmission rates due to suspicion for fecal-oral transmission of the COVID-19. Due to this risk, various countries have started testing wastewater and sewage systems to examine its role in the spread of SARS-CoV-2 among communities. In this review article, we describe the common gastrointestinal manifestations in COVID-19, their prevalence based upon the current literature, and highlight the importance of early recognition and prompt attention. We also note the role of fecal-oral transmission. Furthermore, the mechanisms of these symptoms, the role of medications, and potential contributing factors are also elaborated

DFUNet: Convolutional Neural Networks for Diabetic Foot Ulcer Classification

Globally, in 2016, 1 out of 11 adults suffered from diabetes mellitus. Diabetic foot ulcers (DFU) are a major complication of this disease, which if not managed properly can lead to amputation. Current clinical approaches to DFU treatment rely on patient and clinician vigilance, which has significant limitations, such as the high cost involved in the diagnosis, treatment, and lengthy care of the DFU. We collected an extensive dataset of foot images, which contain DFU from different patients. In this DFU classification problem, we assessed the two classes as normal skin (healthy skin) and abnormal skin (DFU). In this paper, we have proposed the use of machine learning algorithms to extract the features for DFU and healthy skin patches to understand the differences in the computer vision perspective. This experiment is performed to evaluate the skin conditions of both classes that are at high risk of misclassification by computer vision algorithms. Furthermore, we used convolutional neural networks for the first time in this binary classification. We have proposed a novel convolutional neural network architecture, DFUNet, with better feature extraction to identify the feature differences between healthy skin and the DFU. Using 10-fold cross validation, DFUNet achieved an AUC score of 0.961. This outperformed both the traditional machine learning and deep learning classifiers we have tested. Here, we present the development of a novel and highly sensitive DFUNet for objectively detecting the presence of DFUs. This novel approach has the potential to deliver a paradigm shift in diabetic foot care among diabetic patients, which represent a cost-effective, remote, and convenient healthcare solution