A Hybrid Approach Against Black Hole Attackers Using Dynamic Threshold Value and Node Credibility

Detecting black hole attackers is tedious in Vehicular Ad Hoc Networks due to vehicles’ high mobility. The main consequence faced because of these attackers is an increase in the number of dropped packets which converts secure and fastest paths to compromised ones. Since these attackers can act individually and collaboratively as a group, early detection of these attackers must be feasible to preserve the network’s performance. The majority of current methods rely on predetermined threshold and trust score values, which are ineffective in accurately identifying black hole attackers. Hence, this paper proposes a hybrid approach using dynamic threshold value and node credibility for early detection of black hole attackers. RSUs periodically compute the dynamic threshold value and categorize the vehicles into categories 1, 2, and 3. Vehicles classified as Category 1 are legitimate, whereas Category 3 vehicles are attackers. Vehicles in Category 2 are suspicious, requiring further analysis using node credibility values to identify attackers. It is protected against single, multiple, and collaborative black hole attackers. The NS2 simulation results demonstrate that the suggested method is optimal concerning PDR, Throughput, Delay, and Packet Loss Ratio compared to recent techniques. Since the proposed scheme efficiently identifies the attackers, it has 89.67% PDR, which is higher when compared to other schemes

S100A8/A9 drives the formation of procoagulant platelets through GPIbα

S100A8/A9, also known as "calprotectin" or "MRP8/14," is an alarmin primarily secreted by activated myeloid cells with antimicrobial, proinflammatory, and prothrombotic properties. Increased plasma levels of S100A8/A9 in thrombo-inflammatory diseases are associated with thrombotic complications. We assessed the presence of S100A8/A9 in the plasma and lung autopsies from patients with COVID-19 and investigated the molecular mechanism by which S100A8/A9 affects platelet function and thrombosis. S100A8/A9 plasma levels were increased in patients with COVID-19 and sustained high levels during hospitalization correlated with poor outcomes. Heterodimeric S100A8/A9 was mainly detected in neutrophils and deposited on the vessel wall in COVID-19 lung autopsies. Immobilization of S100A8/A9 with collagen accelerated the formation of a fibrin-rich network after perfusion of recalcified blood at venous shear. In vitro, platelets adhered and partially spread on S100A8/A9, leading to the formation of distinct populations of either P-selectin or phosphatidylserine (PS)-positive platelets. By using washed platelets, soluble S100A8/A9 induced PS exposure but failed to induce platelet aggregation, despite GPIIb/IIIa activation and alpha-granule secretion. We identified GPIbα as the receptor for S100A8/A9 on platelets inducing the formation of procoagulant platelets with a supporting role for CD36. The effect of S100A8/A9 on platelets was abolished by recombinant GPIbα ectodomain, platelets from a patient with Bernard-Soulier syndrome with GPIb-IX-V deficiency, and platelets from mice deficient in the extracellular domain of GPIbα. We identified the S100A8/A9-GPIbα axis as a novel targetable prothrombotic pathway inducing procoagulant platelets and fibrin formation, in particular in diseases associated with high levels of S100A8/A9, such as COVID-19

Distinct fibroblast subsets drive inflammation and damage in arthritis.

The identification of lymphocyte subsets with non-overlapping effector functions has been pivotal to the development of targeted therapies in immune-mediated inflammatory diseases (IMIDs). However, it remains unclear whether fibroblast subclasses with non-overlapping functions also exist and are responsible for the wide variety of tissue-driven processes observed in IMIDs, such as inflammation and damage. Here we identify and describe the biology of distinct subsets of fibroblasts responsible for mediating either inflammation or tissue damage in arthritis. We show that deletion of fibroblast activation protein-α (FAPα) fibroblasts suppressed both inflammation and bone erosions in mouse models of resolving and persistent arthritis. Single-cell transcriptional analysis identified two distinct fibroblast subsets within the FAPα population: FAPαTHY1 immune effector fibroblasts located in the synovial sub-lining, and FAPαTHY1 destructive fibroblasts restricted to the synovial lining layer. When adoptively transferred into the joint, FAPαTHY1 fibroblasts selectively mediate bone and cartilage damage with little effect on inflammation, whereas transfer of FAPα THY1 fibroblasts resulted in a more severe and persistent inflammatory arthritis, with minimal effect on bone and cartilage. Our findings describing anatomically discrete, functionally distinct fibroblast subsets with non-overlapping functions have important implications for cell-based therapies aimed at modulating inflammation and tissue damage