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Preprint in English | EuropePMC | ID: ppcovidwho-325846


The demand for same-day delivery (SDD) has increased rapidly in the last few years and has particularly boomed during the COVID-19 pandemic. The fast growth is not without its challenge. In 2016, due to low concentrations of memberships and far distance from the depot, certain minority neighborhoods were excluded from receiving Amazon's SDD service, raising concerns about fairness. In this paper, we study the problem of offering fair SDD-service to customers. The service area is partitioned into different regions. Over the course of a day, customers request for SDD service, and the timing of requests and delivery locations are not known in advance. The dispatcher dynamically assigns vehicles to make deliveries to accepted customers before their delivery deadline. In addition to the overall service rate (utility), we maximize the minimal regional service rate across all regions (fairness). We model the problem as a multi-objective Markov decision process and develop a deep Q-learning solution approach. We introduce a novel transformation of learning from rates to actual services, which creates a stable and efficient learning process. Computational results demonstrate the effectiveness of our approach in alleviating unfairness both spatially and temporally in different customer geographies. We also show this effectiveness is valid with different depot locations, providing businesses with an opportunity to achieve better fairness from any location. Further, we consider the impact of ignoring fairness in service, and results show that our policies eventually outperform the utility-driven baseline when customers have a high expectation on service level.

EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-323544


The coronavirus disease-19 (COVID-19) caused by SARS-CoV-2 infection can lead to a series of clinical settings from non-symptomatic viral carriers/spreaders to severe illness characterized by acute respiratory distress syndrome (ARDS)1,2. A sizable part of patients with COVID-19 have mild clinical symptoms at the early stage of infection, but the disease progression may become quite rapid in the later stage with ARDS as the common manifestation and followed by critical multiple organ failure, causing a high mortality rate of 7-10% in the elderly population with underlying chronic disease1-3. The pathological investigation in the lungs and other organs of fatal cases is fundamental for the mechanistic understanding of severe COVID-19 and the development of specific therapy in these cases. Gross anatomy and molecular markers allowed us to identify, in two fatal patients subject to necropsy, the main pathological features such as exudation and hemorrhage, epithelium injuries, infiltration of macrophages and fibrosis in the lungs. The mucous plug with fibrinous exudate in the alveoli and the activation of alveolar macrophages were characteristic abnormalities. These findings shed new insights into the pathogenesis of COVID-19 and justify the use of interleukin 6 (IL6) receptor antagonists and convalescent plasma with neutralizing antibodies against SARS-CoV-2 for severe patients.Authors Chaofu Wang, Jing Xie, Lei Zhao, Xiaochun Fei, Heng Zhang, and Yun Tan contributed equally to this work. Authors Chaofu Wang, Jun Cai, Rong Chen, Zhengli Shi, and Xiuwu Bian jointly supervised this work.

EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-308281


The demand for same-day delivery (SDD) has increased rapidly in the last few years and has particularly boomed during the COVID-19 pandemic. Existing literature on the problem has focused on maximizing the utility, represented as the total number of expected requests served. However, a utility-driven solution results in unequal opportunities for customers to receive delivery service, raising questions about fairness. In this paper, we study the problem of achieving fairness in SDD. We construct a regional-level fairness constraint that ensures customers from different regions have an equal chance of being served. We develop a reinforcement learning model to learn policies that focus on both overall utility and fairness. Experimental results demonstrate the ability of our approach to mitigate the unfairness caused by geographic differences and constraints of resources, at both coarser and finer-grained level and with a small cost to utility. In addition, we simulate a real-world situation where the system is suddenly overwhelmed by a surge of requests, mimicking the COVID-19 scenario. Our model is robust to the systematic pressure and is able to maintain fairness with little compromise to the utility.

Natl Sci Rev ; 7(12): 1868-1878, 2020 Dec.
Article in English | MEDLINE | ID: covidwho-1087785


Systematic autopsy and comprehensive pathological analyses of COVID-19 decedents should provide insights into the disease characteristics and facilitate the development of novel therapeutics. In this study, we report the autopsy findings from the lungs and lymphatic organs of 12 COVID-19 decedents-findings that evaluated histopathological changes, immune cell signature and inflammatory factor expression in the lungs, spleen and lymph nodes. Here we show that the major pulmonary alterations included diffuse alveolar damage, interstitial fibrosis and exudative inflammation featured with extensive serous and fibrin exudates, macrophage infiltration and abundant production of inflammatory factors (IL-6, IP-10, TNFα and IL-1ß). The spleen and hilar lymph nodes contained lesions with tissue structure disruption and immune cell dysregulation, including lymphopenia and macrophage accumulation. These findings provide pathological evidence that links injuries of the lungs and lymphatic organs with the fatal systematic respiratory and immune malfunction in critically ill COVID-19 patients.

EBioMedicine ; 57: 102833, 2020 Jul.
Article in English | MEDLINE | ID: covidwho-613483


BACKGROUND: The novel coronavirus pneumonia COVID-19 caused by SARS-CoV-2 infection could lead to a series of clinical symptoms and severe illnesses, including acute respiratory distress syndrome (ARDS) and fatal organ failure. We report the fundamental pathological investigation in the lungs and other organs of fatal cases for the mechanistic understanding of severe COVID-19 and the development of specific therapy in these cases. METHODS: The autopsy and pathological investigations of specimens were performed on bodies of two deceased cases with COVID-19. Gross anatomy and histological investigation by Hematoxylin and eosin (HE) stained were reviewed on each patient. Alcian blue/periodic acid-Schiff (AB-PAS) staining and Masson staining were performed for the examinations of mucus, fibrin and collagen fiber in lung tissues. Immunohistochemical staining was performed on the slides of lung tissues from two patients. Real-time PCR was performed to detect the infection of SARS-CoV-2. Flow cytometry analyses were performed to detect the direct binding of S protein and the expression of ACE2 on the cell surface of macrophages. FINDINGS: The main pathological features in lungs included extensive impairment of type I alveolar epithelial cells and atypical hyperplasia of type II alveolar cells, with formation of hyaline membrane, focal hemorrhage, exudation and pulmonary edema, and pulmonary consolidation. The mucous plug with fibrinous exudate in the alveoli and the dysfunction of alveolar macrophages were characteristic abnormalities. The type II alveolar epithelial cells and macrophages in alveoli and pulmonary hilum lymphoid tissue were infected by SARS-CoV-2. S protein of SARS-CoV-2 directly bound to the macrophage via the S-protein-ACE2 interaction. INTERPRETATION: Infection of alveolar macrophage by SARS-CoV-2 might be drivers of the "cytokine storm", which might result in damages in pulmonary tissues, heart and lung, and lead to the failure of multiple organs . FUNDING: Shanghai Guangci Translational Medical Research Development Foundation, Shanghai, China.

Alveolar Epithelial Cells/pathology , Coronavirus Infections/pathology , Cytokine Release Syndrome/pathology , Lung/pathology , Macrophages, Alveolar/pathology , Pneumonia, Viral/pathology , Angiotensin-Converting Enzyme 2 , Autopsy , Betacoronavirus , COVID-19 , China , Coronavirus Infections/mortality , Cytokine Release Syndrome/mortality , Cytokines/blood , Cytokines/metabolism , Female , Humans , Hyperplasia/pathology , Male , Middle Aged , Pandemics , Peptidyl-Dipeptidase A/metabolism , Pneumonia, Viral/mortality , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/metabolism