Detecting -Vertex Cuts in Sparse Networks via a Fast Local Search Approach

The k-vertex cut (k-VC) problem belongs to the family of the critical node detection problems, which aims to find a minimum subset of vertices whose removal decomposes a graph into at least k connected components. It is an important NP-hard problem with various real-world applications, e.g., vulnerability assessment, carbon emissions tracking, epidemic control, drug design, emergency response, network security, and social network analysis. In this article, we propose a fast local search (FLS) approach to solve it. It integrates a two-stage vertex exchange strategy based on neighborhood decomposition and cut vertex, and iteratively executes operations of addition and removal during the search. Extensive experiments on both intersection graphs of linear systems and coloring/DIMACS graphs are conducted to evaluate its performance. Empirical results show that it significantly outperforms the state-of-the-art (SOTA) algorithms in terms of both solution quality and computation time in most of the instances. To evaluate its generalization ability, we simply extend it to solve the weighted version of the k-VC problem. FLS also demonstrates its excellent performance. IEEE

Nebivolol: an effective option against long-lasting dyspnoea following COVID-19 pneumonia - a pivotal double-blind, cross-over controlled study.

Background: Pulmonary microvascular occlusions can aggravate SARS-CoV-2 pneumonia and result in a variable decrease in capillary blood volume (Vc). Dyspnoea may persist for several weeks after hospital discharge in many patients who have "radiologically recovered" from COVID-19 pneumonia. Dyspnoea is frequently "unexplained" in these cases because abnormalities in lung vasculature are understudied. Furthermore, even when they are identified, therapeutic options are still lacking in clinical practice, with nitric oxide (NO) supplementation being used only for severe respiratory failure in the hospital setting. Nebivolol is the only selective ß1 adrenoceptor antagonist capable of inducing nitric oxide-mediated vasodilation by stimulating endothelial NO synthase via ß3 agonism. The purpose of this study was to compare the effect of nebivolol versus placebo in patients who had low Vc and complained of dyspnoea for several weeks after COVID-19 pneumonia. Methods: Patients of both genders, aged ≥18 years, non-smokers, who had a CT scan that revealed no COVID-related parenchymal lesions but still complaining of dyspnoea 12-16 weeks after hospital discharge, were recruited. Spirometrical volumes, blood haemoglobin, SpO2, simultaneous diffusing capacity for carbon monoxide (CO) and NO (DLCO and DLNO, respectively), DLNO/DLCO ratio, Vc and exhaled NO (eNO) were measured together with their dyspnoea score (DS), heart frequency (HF), and blood arterial pressure (BAP). Data were collected before and one week after both placebo (P) and nebivolol (N) (2.5 mg od) double-blind cross-over administered at a two-week interval. Data were statistically compared, and p<0.05 assumed as statistically significant. Results: Eight patients (3 males) were investigated. In baseline, their mean DS was 2.5±0.6 SD, despite the normality of lung volumes. DLCO and DLNO mean values were lower than predicted, while mean DLNO/DLCO ratio was higher. Mean Vc proved substantially reduced. Placebo did not modify any variable (all p=ns) while N improved DLco and Vc significantly (+8.5%, p<0.04 and +17.7%, p<0.003, respectively). eNO also was significantly increased (+17.6%, p<0.002). Only N lowered the dyspnoea score (-76%, p<0.001). Systolic and diastolic BAP were slightly lowered (-7.5%, p<0.02 and -5.1%, p<0.04, respectively), together with HF (-16.8%, p<0.03). Conclusions: The simultaneous assessment of DLNO, DLCO, DLNO/DLCO ratio, and Vc confirmed that long-lasting dyspnoea is related to hidden abnormalities in the lung capillary vasculature. These abnormalities can persist even after the complete resolution of parenchymal lesions regardless of the normality of lung volumes. Nebivolol, but not placebo, improves DS and Vc significantly. The mechanism suggested is the NO-mediated vasodilation via the ß3 adrenoceptor stimulation of endothelial NO synthase. This hypothesis is supported by the substantial increase of eNO only assessed after nebivolol. As the nebivolol tolerability in these post-COVID normotensive patients was very good, the therapeutic use of nebivolol against residual and symptomatic signs of long-COVID can be suggested in out-patients.

Effect of medical staff training on vaccination coverage in outpatients with cancer: An interventional multicenter before-and-after study.

Purpose: Despite widely disseminated guidelines, pneumococcal and influenza vaccination coverage (VC) remains insufficient in patients with cancer receiving cancer treatment. We performed an interventional study to evaluate VC in patients with cancer treated at the medical oncology departments of three North-of-France hospitals and to assess the effect of medical staff training on VC in these patients. Methods: A standardized questionnaire assessed VC in adult patients with cancer receiving anticancer treatment at three day hospitals during December 2-7, 2019. Subsequently (January 2020), we organized educational training sessions for medical staff from each hospital to discuss the current vaccination guidelines. To assess the impact of training on pneumococcal and influenza VC, we re-administered the same questionnaire in March 2020. Because there are no specific guidelines on Diphtheria-Tetanus-Pertussis (DTP) vaccination and no improvement was expected, DTP VC acted as an internal control. Results: In total, 272 patients from all three hospitals were enrolled in the "before study"; 156 patients from only two hospitals were enrolled in the "after study" as medical training and data collection at the third were impossible because of administrative reasons and COVID-19 pandemic. The predictors were age for DTP VC; treatment center for pneumococcal VC; and age, sex, and tumor histology (adenocarcinoma vs. others) for influenza VC. Neither influenza VC (42.6% vs. 55.1%, p = 0.08), nor pneumococcal VC were significantly improved post-intervention (11.8% vs. 15.4%, p = 1). There seems to be a small effect in the most fragile for influenza VC. Conclusion: As expected, VC was very low in patients with cancer, consistent with the literature. There was no impact of the intervention for pneumococcal and influenza VC.

Validation of a Simulink Model for Simulating the Two Typical Controlled Ventilation Modes of Intensive Care Units Mechanical Ventilators

Mechanical ventilators are vital components of critical care services for patients with severe acute respiratory failure. In particular, pressure- and volume-controlled mechanical ventilation systems are the typical modes used in intensive care units (ICUs) to ventilate patients who cannot breathe adequately on their own. In this paper, a Simulink model is proposed to simulate these two typical modes employed in intensive care lung ventilators. Firstly, these two modes of ventilation are described in detail in the present paper. Secondly, the suggested Simulink model is analysed: it consists of using well-established subroutines already present in Simulink through the Simscape Fluids (gas) library, to simulate all the pneumatic components employed in some commercial ICU ventilators, such as pressure reducing valves, pressure relief valves, check valves, tanks, ON\OFF and proportional directional valves, etc. Finally, the simulation results of both modes in terms of pressure, tidal volume, and inspired/expired flow are compared with the real-life quantitative trends taken from previously recorded real-life experiments in order to validate the Simulink model. The accuracy of the model is high, as the numerical predictions are in good agreement with the real-life data, the percentage error being less than 10% in most comparisons. In this way, the model can easily be used by manufacturers and start-ups in order to produce new mechanical ventilators in the shortest time possible. Moreover, it can also be used by doctors and trainees to evaluate how the mechanical ventilator responds to different patients.

SASC: A simple approach to synthetic cohorts for generating longitudinal observational patient cohorts from COVID-19 clinical data.

One of the impacts of the coronavirus disease 2019 (COVID-19) pandemic has been a push for researchers to better exploit synthetic data and accelerate the design, analysis, and modeling of clinical trials. The unprecedented clinical efforts caused by COVID-19's emergence will certainly boost future robust and innovative approaches of statistical sciences applied to clinical fields. Here, we report the development of SASC, a simple but efficient approach to generate COVID-19-related synthetic clinical data through a web application. SASC takes basic summary statistics for each group of patients and attempts to generate single variables according to internal correlations. To assess the "reliability" of the results, statistical comparisons with Synthea, a known synthetic patient generator tool, and, more importantly, with clinical data of real COVID-19 patients are provided. The source code and web application are available on GitHub, Zenodo, and Mendeley Data.

Covid-19 pandemic endorses new era of e-learning case study: Hashemite university

Technology has affected the development of the education process over time. COVID-19 pandemic has forced educational facilities to close. Consequently, transformation from face-to-face educational approach to the E-learning approach has pushed the world to enter a new state of learning. This situation has elicited doubts about the implementation and the difficulties related with this immediate action. In this paper, statistical analysis was used on the filled survey by the instructors and students at the Hashemite University (HU) to investigate the quality of the E-learning process. Various factors such as e-content, Virtual Classroom (VC) and Learning Management System (LMS), and Technology Infrastructure affect E-learning process. A contradiction between instructors’ and students’ opinions regarding the usage of the E-learning at HU exists. Therefore, a set of recommendations was made to overcome the shortage in the E-learning process and to reach a full satisfaction about the quality of its implementation in future. © Italian E-learning Association.

Forensic Assessment in the Time of COVID-19: The Colorado Experience in Developing Videoconferencing for Evaluating Adjudicative Competency

In this article, we briefly discuss how competency to proceed evaluations are conducted within the state of Colorado, the impact that COVID-19 had on forensic evaluations within the Colorado forensic services system, and the acquisition and adoption of videoconferencing (VC) capabilities. We then shift to an in-depth consideration of how VC forensic evaluations are facilitated in four different contexts: for adult defendants in custody, on bond, and in hospitals, and for juvenile defendants. Challenges and limitations are also addressed.

Changing to remote management of a community heart failure population during COVID-19 - Clinician and patient perspectives'.

BACKGROUND: The COVID pandemic has challenged the traditional methods used in care of patients with heart failure (HF). Remote management of HF patients has been recommended in order to maintain routine standards of care, but satisfaction with this platform of care is unknown. We set out to address the physician and patient opinion of remote management of HF during COVID-19. METHODS AND RESULTS: An observational report of the use of a Structured Telephonic assessment (STA) in stable outpatient HF patients. Physician grading of the STA was complemented by 100 randomly chosen patients to ascertain patient satisfaction and comment. 278 patients underwent a STA. Patient preference for STA was noted in 66%. Convenience was the single most cited reason for this preference (83.3%). The STA was deemed satisfactory by clinicians in 67.6%. The two-leading reasons for clinician dissatisfaction were data gaps providing a barrier to titration (55.6%) and need for clinical exam (18.9%). The annual review appointment visit subtype possessed the highest levels of satisfaction congruence amongst both clinicians and patients. CONCLUSION: In summary, this report demonstrates reasonable patient / physician satisfaction with STA, and provides some direction on how this care platform might be sustained beyond the COVID crisis.

Projected lung areas using dynamic X-ray (DXR).

BACKGROUND: Dynamic X-ray (DXR) provides images of multiple phases of breath with less radiation exposure than CT. The exact images at end-inspiratory or end-expiratory phases can be chosen accurately. PURPOSE: To investigate the correlation of the projected lung area (PLA) by dynamic chest X-ray with pulmonary functions. MATERIAL AND METHODS: One hundred sixty-two healthy volunteers who received medical check-ups for health screening were included in this study. All subjects underwent DXR in both posteroanterior (PA) and lateral views and pulmonary function tests on the same day. All the volunteers took several tidal breaths before one forced breath as instructed. The outlines of lungs were contoured manually on the workstation with reference to the motion of diaphragm and the graph of pixel values. The PLAs were calculated automatically, and correlations with pulmonary functions and demographic data were analyzed statistically. RESULTS: The PLAs have correlation with physical characteristics, including height, weight and BMI, and pulmonary functions such as vital capacity (VC) and forced expiratory volume in one second (FEV1). VC and FEV1 revealed moderate correlation with the PLAs of PA view in forced inspiratory phase (VC: right, r = 0.65; left, r = 0.69. FEV1: right, r = 0.54; left, r = 0.59). Multivariate analysis showed that body mass index (BMI), sex and VC were considered independent correlation factors, respectively. CONCLUSION: PLA showed statistically significant correlation with pulmonary functions. Our results indicate DXR has a possibility to serve as an alternate method for pulmonary function tests in subjects requiring contact inhibition including patients with suspected or confirmed covid-19.