8 research outputs found

    Off-Path TCP Exploits of the Mixed IPID Assignment

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    In this paper, we uncover a new off-path TCP hijacking attack that can be used to terminate victim TCP connections or inject forged data into victim TCP connections by manipulating the new mixed IPID assignment method, which is widely used in Linux kernel version 4.18 and beyond to help defend against TCP hijacking attacks. The attack has three steps. First, an off-path attacker can downgrade the IPID assignment for TCP packets from the more secure per-socket-based policy to the less secure hash-based policy, building a shared IPID counter that forms a side channel on the victim. Second, the attacker detects the presence of TCP connections by observing the shared IPID counter on the victim. Third, the attacker infers the sequence number and the acknowledgment number of the detected connection by observing the side channel of the shared IPID counter. Consequently, the attacker can completely hijack the connection, i.e., resetting the connection or poisoning the data stream. We evaluate the impacts of this off-path TCP attack in the real world. Our case studies of SSH DoS, manipulating web traffic, and poisoning BGP routing tables show its threat on a wide range of applications. Our experimental results show that our off-path TCP attack can be constructed within 215 seconds and the success rate is over 88%. Finally, we analyze the root cause of the exploit and develop a new IPID assignment method to defeat this attack. We prototype our defense in Linux 4.18 and confirm its effectiveness through extensive evaluation over real applications on the Internet

    Failure Mechanism and Optimization of Arch-Bolt Composite Support for Underground Mining Tunnel

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    Numerical simulation tests were performed on the arch-bolt combined supported mining tunnel through an improved numerical simulation approach. The typical soft rock roadway was took as the background, and the influencing factors such as ground stress level, lateral pressure coefficient, and support type and parameters were considered. The failure mechanism of a semicircular roadway with two straight walls was analyzed; results showed that the arch legsā€™ inward bending deformation and the arch-rock separation are the breakthrough of the global failure of the supporting system, and rock bolts breakage promoted the failure process. The effects of different controlling measures were analyzed including enlarging the bolt diameter, replacing the conventional bolts with energy-absorbing bolts, and setting arch locking bolts on the arch legs. The field test of the concrete-filled steel tube (CFST) arch-bolt composite support scheme was carried out in a high-stress soft rock roadway, and the results indicate the reliability of the main conclusions

    <i>Coxiella burnetii</i> and <i>Bartonella</i> Endocarditis Diagnosed by Metagenomic Next-Generation Sequencing

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    (1) Background: Culture-negative endocarditis is challenging to diagnose. Here, we retrospectively identified 23 cases of Coxiella burnetii and Bartonella endocarditis by metagenomic next-generation sequencing. (2) Methods: Twenty-three patients with culture-negative endocarditis were retrospectively enrolled from Guangdong Provincial Peopleā€™s Hospital (n = 23) between April 2019 and December 2021. Metagenomic next-generation sequencing was performed on blood (n = 22) and excised cardiac valvular tissue samples (n = 22) for etiological identification, and Sanger sequencing was performed for pathogenic diagnostic verification. The demographic and clinical data of the 23 patients were obtained from hospital electronic health records. (3) Results: A total of 23 male patients (median age, 56 years (interquartile range, 16)) with culture-negative endocarditis were diagnosed with Coxiella burnetii (n = 21) or Bartonella (n = 2) species infection by metagenomic next-generation sequencing. All patients underwent cardiac surgery. The resected tissue exhibited both a significantly higher number of unique suspected pathogen read-pairs and more unique pathogen read-pairs than the blood specimens. The results of Sanger sequencing tests on all remaining tissue and blood specimens were positive. Oral doxycycline was added to the antibiotic regimen for at least 1.5 years according to etiology. A total of 21 patients (91%) were discharged, and 20 patients were healthy at the 21-month (interquartile range, 15) follow-up visit. One patient exhibited endocarditis relapse with the same pathogen from inadequate antibiotic administration. The last 2 patients (9%) developed septic shock and multiple organ dysfunction syndrome postoperatively and died shortly after discharge. (4) Conclusions: CNE caused by C. burnetii and Bartonella species is challenging to diagnose and exhibits poor outcome due to delayed treatment. In response, mNGS, characterized by high sensitivity and rapid results, is an effective alternative for the etiological identification of C. burnetii and Bartonella endocarditis

    Nanosilver Embedded in a Magnetosome Nanoflower to Enhance Antibacterial Activity for Wound Dressing Applications

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    The natural biofilm on magnetosomes obtained from the biomineralization of magnetotactic bacteria, which replaced a complex chemical modification process on the surface of Fe3O4, can be used as the organic component and copper(II) ions as the inorganic component to form organicā€“inorganic nanoflowers in phosphate systems. Characterization by scanning electron microscopy, Fourier transform infrared spectroscopy, and vibrating-sample magnetometry proved that magnetic nanoflowers loaded with silver ions (Ag/MN-CuƗNFs) were successfully fabricated. In vitro antibacterial experiments demonstrated that Ag/MN-CuƗNFs displayed strong antibacterial effects against Escherichia coli and Staphylococcus aureus, with minimum inhibitory concentrations of 10 and 80 Ī¼g/mL, respectively. Ag/MN-CuƗNFs, which possessed good biocompatibility as confirmed by cytotoxicity and hemolysis tests, were able to promote wound healing in the face of bacterial infection in vivo without causing toxicity to major organs. Therefore, magnetosomes as a natural carrier have great application potential in the synthesis of multifunctional magnetosomes by direct hybridization with a target substance

    Sarcopenia in Patients With Normal Body Mass Index Is an Independent Predictor for Postoperative Complication and Longā€Term Survival in Gastric Cancer

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    Malnutrition in patients with gastric cancer (GC) with normal body mass index (BMI) is often ignored. This study aimed to explore the role of sarcopenia in predicting postoperative complication and longā€term survival in patients with GC with normal BMI. We included patients with normal BMI (18.5Ā kg/m2Ā ā‰¤Ā BMIĀ <Ā 23Ā kg/m2) who underwent radical gastrectomy between July 2014 and December 2016. Sarcopenia was assessed by muscle mass, handgrip strength, and gait speed. Kaplanā€“Meier survival analysis was used to analyze the association between sarcopenia and the prognosis of patients with GC. Univariate and multivariate analyses were used to identify risk factors contributing to postoperative complications and longā€term survival. Overall, 267 patients with GC with normal BMI were included in this study; of which 49 (18.35%) patients were diagnosed with sarcopenia. Patients with sarcopenia had higher incidence of a major postoperative complication, longer postoperative hospital stays, and greater hospital costs. The Kaplanā€“Meier survival analysis showed that patients with sarcopenia had poorer overall survival than nonā€sarcopenia patients. Univariate and multivariate analyses showed that sarcopenia was an independent predictor for postoperative complication and longā€term survival in such patients. Sarcopenia is an independent predictor for postoperative complications and longā€term survival in patients with normal BMI after radical gastrectomy for GC. We recommend that patients with normal BMI should perform nutritional risk screening by sarcopenia

    Engineering metal-organic framework nanoparticles trigger pyroptosis to boost colon cancer immunotherapy

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    Pyroptosis, which is a novel form of immunogenic cell death, plays a vital role in antitumor therapy. Zirconium-based metalā€“organic frameworks (Zr-MOFs) have been applied in various antitumor treatments. However, the intrinsic role of these frameworks in pyroptosis has yet to be determined. Here, a Zr-MOF-based nanosystem (DOX@Zr-MOF) was constructed by loading Zr-MOF nanoparticles with the chemotherapeutic drug doxorubicin (DOX) to synergistically trigger cancer cell pyroptosis. We found that DOX@Zr-MOF rapidly triggered pyroptosis via activation of the canonical caspase-3/gasdermin E (GSDME)-dependent pathway, resulting in significant suppression of CT26 colon tumor growth in vitro and in vivo. Furthermore, DOX@Zr-MOF significantly enhanced the systemic antitumor immune response by reprogramming the immunosuppressive tumor microenvironment. In addition, the combination of DOX@Zr-MOF with programmed cell death-1 (PD-1) immunotherapy strongly improved the antitumor efficacy of CT26 colon tumors. Overall, this work provides a promising strategy for pyroptosis-mediated anticancer treatment, which may efficiently improve checkpoint blockade-related cancer immunotherapy
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