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Background: Necrotizing fasciitis (NF) is a rare but potentially life-threatening soft tissue infection. The objective of this study was to assess the association between timely surgery within 6 h and hospital mortality in patients with limb NF, and to describe the trends in patients with NF, time to surgery and standardized mortality ratio (SMR) over 11 years. Methods: This was a multicenter, retrospective cohort study of all intensive care unit patients who had emergency surgery within 24 h of hospitalization for limb NF between April 1, 2008 and March 31, 2019 in Hong Kong. Timely surgery was defined as the first surgical treatment within 6 h of initial hospitalization. Appropriate antibiotics were achieved if the patient was given antibiotic(s) for all documented pathogens prior to or on day of culture results. The primary outcome was hospital mortality. Results: There were 495 patients (median age 62 years, 349 (70.5%) males) with limb NF treated by surgery within 24 h of hospitalization over the 11 years. Appropriate antibiotic(s) were used in 392 (79.2%) patients. There were 181 (36.5%) deaths. Timely surgery was not associated with hospital mortality (Relative Risk 0.89, 95% CI: 0.73 to 1.07) but admission year, advanced age, higher severity of illness, comorbidities, renal replacement therapy, vasopressor use, and type of surgery were significant predictors in the multivariable model. There was an upward trend in NF diagnosis (1.9 cases/year, 95% CI: 0.7 to 3.1; P < 0.01; R2 = 0.60) but there was no downward trend in median time to surgery (-0.2 h/year, 95% CI: -0.4 to 0.1; P = 0.16) or SMR (-0.02/year, 95% CI: -0.06 to 0.01; P = 0.22; R2 = 0.16). Conclusions: Among patients operated within 24 h, very early surgery within 6–12 h was not associated with survival. Increasing limb NF cases were reported each year but mortality remained high despite a high rate of appropriate antibiotic use and timely surgical intervention. [ABSTRACT FROM AUTHOR]

Network security is one of the primary concerns when deploying IoT applications. A proper authentication scheme can strengthen network security and resilience against malicious attacks. The quantitative comparison among authentication schemes is rarely found. Thus, it is difficult to choose the appropriate authentication scheme objectively. This paper presents a quantitative comparison of three authentication schemes, including blockchain‐based authentication, a widely discussed new approach for IoT security. This paper focuses on network‐level simulation instead of the protocol, providing a different angle when evaluating an authentication scheme. The simulations include five common topologies in IoT networks under five different attack strategies. The results show that the blockchain‐based scheme has the most substantial resilience compared to PKI‐based and PSK methods, while the computational cost is 1% less than the PKI‐based method. In addition, the PSK method is most energy efficient as its computational cost is only around 1% of PKI‐based and blockchain‐based methods. [ABSTRACT FROM AUTHOR]

The application of IoT covers various domains, including smart cities, smart homes, e‐health, autonomous vehicles and so forth. These are powered by IoT networks which consist of a collection of heterogeneous devices. These devices collect and analyze personal data and sometimes make decisions for us. Since IoTs are involved in the decision‐making process, the authenticity and privacy of such networks are critical. In this article, authenticated devices configuration protocol (ADCP) is proposed to handle the authentication and construct a secure overlay network in the existing IoT networks; authenticated device transmission protocol is also proposed to secure the communication within the overlay network. Besides the authentication, ADCP can also mitigate the zero‐day attack and achieve zero the zero‐day attack can also be mitigated and achieved 0 round trip time key exchange. These protocols utilize a distributed blockchain database to store the authentication records optimized for data integrity. These properties guarantee the integrity of the authentication records. Both protocols are compatible with the existing communication protocols and do not require reprogramming the current software. The formal analysis of the proposed scheme has proven its resilience against various possible attacks. In addition, a stochastic threat model is considered and numerical results give solid evidence of security enhancement. [ABSTRACT FROM AUTHOR]