114 research outputs found

    The Case for Ubiquitous Transport-Level Encryption

    Get PDF
    Today, Internet traffic is encrypted only when deemed necessary. Yet modern CPUs could feasibly encrypt most traffic. Moreover, the cost of doing so will only drop over time. Tcpcrypt is a TCP extension designed to make end-to-end encryption of TCP traffic the default, not the exception. To facilitate adoption tcpcrypt provides backwards compatibility with legacy TCP stacks and middle-boxes. Because it is implemented in the transport layer, it protects legacy applications. However, it also provides a hook for integration with application-layer authentication, largely obviating the need for applications to encrypt their own network traffic and minimizing the need for duplication of functionality. Finally, tcpcrypt minimizes the cost of key negotiation on servers; a server using tcpcrypt can accept connections at 36 times the rate achieved using SSL

    Reproducibility and sensitivity to change of various methods to measure joint space width in osteoarthritis of the hip: a double reading of three different radiographic views taken with a three-year interval

    Get PDF
    Joint space width (JSW) and narrowing (JSN) measurements on radiographs are currently the best way to assess disease severity or progression in hip osteoarthritis, yet we lack data regarding the most accurate and sensitive measurement technique. This study was conducted to determine the optimal radiograph and number of readers for measuring JSW and JSN. Fifty pairs of radiographs taken three years apart were obtained from patients included in a structure modification trial in hip osteoarthritis. Three radiographs were taken with the patient standing: pelvis, target hip anteroposterior (AP) and oblique views. Two trained readers, blinded to each other's findings, time sequence and treatment, each read the six radiographs gathered for each patient twice (time interval ≥15 days), using a 0.1 mm graduated magnifying glass. Radiographs were randomly coded for each reading. The interobserver and intraobserver cross-sectional (M0 and M36) and longitudinal (M0–M36) reproducibilities were assessed using the intraclass coefficient (ICC) and Bland–Altman method for readers 1 and 2 and their mean. Sensitivity to change was estimated using the standardized response mean (SRM = change/standard deviation of change) for M0–M36 changes. For interobserver reliability on M0–M36 changes, the ICCs (95% confidence interval [CI]) were 0.79 (0.65–0.88) for pelvic view, 0.87 (0.78–0.93) for hip AP view and 0.86 (0.76–0.92) for oblique view. Intraobserver reliability ICCs were 0.81 (0.69–0.89) for observer 1 and 0.97 (0.95–0.98) for observer 2 for the pelvic view; 0.87 (0.78–0.92) and 0.97 (0.96–0.99) for the hip AP view; and 0.73 (0.57–0.84) and 0.93 (0.88–0.96) for the oblique view. SRMs were 0.61 (observer 1) and 0.82 (observer 2) for pelvic view; 0.64 and 0.75 for hip AP view; and 0.77 and 0.70 for oblique view. All three views yielded accurate JSW and JSN. According to the best reader, the pelvic view performed slightly better. Both readers exhibited high precision, with SRMs of 0.6 or greater for assessing JSN over three years. Selecting a single reader was the most accurate method, with 0.3 mm precision. Using this cutoff, 50% of patients were classified as 'progressors'

    DDoS defense by offense

    Get PDF
    This article presents the design, implementation, analysis, and experimental evaluation of speak-up, a defense against application-level distributed denial-of-service (DDoS), in which attackers cripple a server by sending legitimate-looking requests that consume computational resources (e.g., CPU cycles, disk). With speak-up, a victimized server encourages all clients, resources permitting, to automatically send higher volumes of traffic. We suppose that attackers are already using most of their upload bandwidth so cannot react to the encouragement. Good clients, however, have spare upload bandwidth so can react to the encouragement with drastically higher volumes of traffic. The intended outcome of this traffic inflation is that the good clients crowd out the bad ones, thereby capturing a much larger fraction of the server's resources than before. We experiment under various conditions and find that speak-up causes the server to spend resources on a group of clients in rough proportion to their aggregate upload bandwidths, which is the intended result.National Science Foundation (U.S.) (NSF grant CNS-0225660)National Science Foundation (U.S.) (NSF grant CNS-0520241)United States. Dept. of Defense (National Security Science and Engineering Faculty Fellowship

    Epigenetic regulation of RhoB loss of expression in lung cancer

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>RhoB is down-regulated in most lung cancer cell lines and tumor tissues when compared with their normal counterparts. The mechanism of this loss of expression is not yet deciphered.</p> <p>Methods</p> <p>Since no mutation has been reported in the RhoB sequence, we investigated the epigenetic regulation of RhoB expression by analyzing the effect of HDAC inhibitors and methyltransferase inhibitors, by direct sequencing after bisulfite treatment and by methylation specific PCR.</p> <p>Results</p> <p>We first showed that histone deacetylase (HDAC) inhibitors induce a significant RhoB re-expression in lung cancer cell lines whereas only a slight effect was observed with methyl transferase inhibitors. As promoter methylation is the most common epigenetic process in lung cancer, we performed methylation specific PCR and sequence analysis after bisulfite treatment and demonstrated that RhoB was methylated neither in lung cancer cell lines nor in tumor tissues. We also showed that a variable number of tandem repeats sequences in the 5' region of the RhoB gene was involved in HDAC response.</p> <p>Conclusion</p> <p>We thus propose that RhoB regulation of expression occurs mainly by histone deacetylation rather than by promoter hypermethylation and that this process can be modulated by specific 5' sequences within the promoter.</p

    Targeting RET in Patients With RET-Rearranged Lung Cancers: Results From the Global, Multicenter RET Registry.

    Get PDF
    Purpose In addition to prospective trials for non-small-cell lung cancers (NSCLCs) that are driven by less common genomic alterations, registries provide complementary information on patient response to targeted therapies. Here, we present the results of an international registry of patients with RET-rearranged NSCLCs, providing the largest data set, to our knowledge, on outcomes of RET-directed therapy thus far. Methods A global, multicenter network of thoracic oncologists identified patients with pathologically confirmed NSCLC that harbored a RET rearrangement. Molecular profiling was performed locally by reverse transcriptase polymerase chain reaction, fluorescence in situ hybridization, or next-generation sequencing. Anonymized data-clinical, pathologic, and molecular features-were collected centrally and analyzed by an independent statistician. Best response to RET tyrosine kinase inhibition administered outside of a clinical trial was determined by RECIST v1.1. Results By April 2016, 165 patients with RET-rearranged NSCLC from 29 centers across Europe, Asia, and the United States were accrued. Median age was 61 years (range, 29 to 89 years). The majority of patients were never smokers (63%) with lung adenocarcinomas (98%) and advanced disease (91%). The most frequent rearrangement was KIF5B-RET (72%). Of those patients, 53 received one or more RET tyrosine kinase inhibitors in sequence: cabozantinib (21 patients), vandetanib (11 patients), sunitinib (10 patients), sorafenib (two patients), alectinib (two patients), lenvatinib (two patients), nintedanib (two patients), ponatinib (two patients), and regorafenib (one patient). The rate of any complete or partial response to cabozantinib, vandetanib, and sunitinib was 37%, 18%, and 22%, respectively. Further responses were observed with lenvantinib and nintedanib. Median progression-free survival was 2.3 months (95% CI, 1.6 to 5.0 months), and median overall survival was 6.8 months (95% CI, 3.9 to 14.3 months). Conclusion Available multikinase inhibitors had limited activity in patients with RET-rearranged NSCLC in this retrospective study. Further investigation of the biology of RET-rearranged lung cancers and identification of new targeted therapeutics will be required to improve outcomes for these patients

    Factors for Hematopoietic Toxicity of Carboplatin: Refining the Targeting of Carboplatin Systemic Exposure

    Get PDF
    Purpose Area under the curve (AUC) dosing is routinely carried out for carboplatin, but the chosen target AUC values remain largely empirical. This multicenter pharmacokinetic-pharmacodynamic (PK-PD) study was performed to determine the covariates involved in the interindividual variability of carboplatin hematotoxicity that should be considered when choosing individual target AUCs.Patients and Methods Three hundred eighty-three patients received carboplatin as part of established regimens. A semi-physiologic population PK-PD model was applied to describe separately the time course of absolute neutrophil and platelet counts using NONMEM software. The plasma ultrafiltrable carboplatin concentration (CCarbo) was assumed to inhibit the proliferation of blood cell precursors through a linear model: drug effect = slope × CCarbo. The slope corresponds to the patients\u27 sensitivity to carboplatin hematotoxicity. The relationships between the patients\u27 sensitivity to the neutropenic or thrombopenic effects of carboplatin and various covariates, including associated chemotherapies, demographic, biologic, and pharmacogenetic data, were studied. Results The sensitivity of carboplatin-induced thrombocytopenia decreased in the case of concomitant paclitaxel chemotherapy (slope decreased by 24%), whereas it increased with coadministration of etoposide and gemcitabine (slope increased by 45% and 133%, respectively). For neutropenia, the sensitivity increased when carboplatin was combined with other cytotoxics (slope increased by 76%). Conclusion This study provides useful information to clinicians to better estimate the hematopoietic toxicity of carboplatin and thus choose more rationally carboplatin target AUCs as a function of pretreatment or concomitantly administered chemotherapies. For example, an AUC of 5 mg/mL · min is associated with a risk of grade 3 or 4 thrombocytopenia of 2% in combination with paclitaxel versus 38% with gemcitabine in a non-pretreated patient
    corecore