Patients with epidemic infections caused by Neisseria meningitidis serogroup C were studied to assess the relationship of abnormal coagulation parameters to prognosis. Patients were categorized into stages within the first hour of observation according to severity of illness. During the epidemic years 1986 through 1991, 113 patients with bacteriologically proven N. meningitidis infection were observed, 15 of whom died. Purpura fulminans was seen in 28 patients, of whom 14 (50%) died. Among the 14 surviving patients who had purpura fulminans, 10 suffered gangrene with deforming autoamputation secondary to the dermal microvascular thrombosis and hemorrhagic necrosis. Evaluation of the induced diffuse intravascular coagulation in 59 patients included studies of the naturally occurring anticoagulants, focusing on protein C and protein S. The magnitude of the declining levels of protein C, the degree of thrombocytopenia, and the presence of fibrin split products are directly related to the clinical severity of the illness (P = .0053). Thus, in individuals with severe disease expression, the risk of purpura fulminans with death or deformity was significantly increased when the platelet count was < 50,000 cells/mm3 (P = .0001) and protein C levels were low (P = .0158). The immaturity of the protein C system in children who are < 4 years of age may contribute to the rapid and more frequent pathogenesis of purpura fulminans. Therapy directed at replacement of the naturally occurring anticoagulants, such as protein C, may ultimately improve the prognosis for individuals with purpura fulminans.
Problem definition: This paper investigates the impact of COVID-19 on e-commerce sales and the underlying operational driver. Academic/practical relevance: As COVID-19 continues to disrupt offline retail, anecdotal evidence suggests a rapid growth of e-commerce. However, the pandemic may also significantly decrease offline logistics capacity, which in turn decreases e-commerce sales. Then, how does e-commerce respond to COVID-19, and what are the corresponding opportunities and challenges? Methodology: We leverage e-commerce sales data from Alibaba and construct a city-day panel across three years, representing sales for all buyers and sellers on the platform across 339 cities in mainland China. We develop three identification strategies to estimate the overall impact of COVID-19 (based on a year-on-year comparison), the impact of COVID-19 intensity (based on the different number of cases across cities), and the impact of corresponding containment measures (leveraging policy changes of checkpoint, partial shutdown, and complete shutdown measures across cities). Results: We provide two key findings. First, across different identification strategies, we observe a common drop and recovery pattern, which illustrates the digital resilience of e-commerce during the pandemic. For example, we estimate an overall decrease of 22% in e-commerce sales during the period of the Wuhan shutdown (January 23–April 7, 2020). However, it recovers in most cities within five weeks. Second, we identify a key operational driver—logistics capacity—that significantly explains the decline and recovery of e-commerce sales during and after the outbreak. Managerial implications: We provide important evidence on how e-commerce responds to and recovers from COVID-19, contrary to the common perception. The evidence in the recovery phase can also inform platforms and policymakers to design digital strategies and invest in logistics infrastructure.
Online retailers often face the decision on whether they should implement a word-of-mouth (WOM) system on their websites. Some retailers opt not to have an in-site WOM system (e.g., Tiffany.com and Tjmaxx.com ), whereas others implement and manage an internal WOM system (e.g., Amazon.com and Macys.com ). According to a new study in Information Systems Research, authors Ni Huang (Arizona State University), Tianshu Sun (University of Southern California), Peiyu Chen (Arizona State University), and Joseph M. Golden ( Collage.com ) conducted a randomized field experiment to examine how implementing an in-site WOM system from ground zero influences customer conversion in an online retailing website. Their results demonstrate that implementing an in-site WOM system can be a double-edged sword to the online retailing website. Specifically, the impact of a WOM system implementation on customer conversion is moderated by WOM volume, such that its effect is positive above a threshold of volume and negative below the threshold. Additionally, the researchers find that WOM valence reinforces the impact of a WOM system on customer conversion. These results offer important implications for the hundreds-of-billion-dollar online retailing industry on the implementation and management of online WOM systems.
The rapid development of modern photonic technologies—for example, mercury-free lamps, flat-panel displays, and solid-state lamps—demands the timely discovery of advanced phosphors. A combinatorial process has been developed to dramatically accelerate the experimental search for such phosphors. High-density phosphor “libraries” containing from 100 to over 1000 discrete chemical compositions on a 1 in. × 1 in. substrate have been made in thin-film or powder form using selective vapor deposition and liquid-dispensing techniques, respectively. In this article, the existing methods of combinatorial synthesis and screening of phosphors will be reviewed with examples. These methods may also be used to screen organic-based solid-state materials and optimize their device properties. In this regard, combinatorial and spreading techniques have been utilized to study and rapidly optimize organic light-emitting devices (OLEDs).
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