2,847 research outputs found

    SoK: Cryptographically Protected Database Search

    Full text link
    Protected database search systems cryptographically isolate the roles of reading from, writing to, and administering the database. This separation limits unnecessary administrator access and protects data in the case of system breaches. Since protected search was introduced in 2000, the area has grown rapidly; systems are offered by academia, start-ups, and established companies. However, there is no best protected search system or set of techniques. Design of such systems is a balancing act between security, functionality, performance, and usability. This challenge is made more difficult by ongoing database specialization, as some users will want the functionality of SQL, NoSQL, or NewSQL databases. This database evolution will continue, and the protected search community should be able to quickly provide functionality consistent with newly invented databases. At the same time, the community must accurately and clearly characterize the tradeoffs between different approaches. To address these challenges, we provide the following contributions: 1) An identification of the important primitive operations across database paradigms. We find there are a small number of base operations that can be used and combined to support a large number of database paradigms. 2) An evaluation of the current state of protected search systems in implementing these base operations. This evaluation describes the main approaches and tradeoffs for each base operation. Furthermore, it puts protected search in the context of unprotected search, identifying key gaps in functionality. 3) An analysis of attacks against protected search for different base queries. 4) A roadmap and tools for transforming a protected search system into a protected database, including an open-source performance evaluation platform and initial user opinions of protected search.Comment: 20 pages, to appear to IEEE Security and Privac

    Automating Logic Transformations With Approximate SPFDs

    Full text link

    Bandwidth and Electron Correlation-Tuned Superconductivity in Rb0.8_{0.8}Fe2_{2}(Se1−z_{1-z}Sz_z)2_2

    Full text link
    We present a systematic angle-resolved photoemission spectroscopy study of the substitution-dependence of the electronic structure of Rb0.8_{0.8}Fe2_{2}(Se1−z_{1-z}Sz_z)2_2 (z = 0, 0.5, 1), where superconductivity is continuously suppressed into a metallic phase. Going from the non-superconducting Rb0.8_{0.8}Fe2_{2}(Se1−z_{1-z}Sz_z)2_2 to superconducting Rb0.8_{0.8}Fe2_{2}Se2_2, we observe little change of the Fermi surface topology, but a reduction of the overall bandwidth by a factor of 2 as well as an increase of the orbital-dependent renormalization in the dxyd_{xy} orbital. Hence for these heavily electron-doped iron chalcogenides, we have identified electron correlation as explicitly manifested in the quasiparticle bandwidth to be the important tuning parameter for superconductivity, and that moderate correlation is essential to achieving high TCT_C

    Impact of Processing Conditions on Inter-tablet Coating Thickness Variations Measured by Terahertz In-Line Sensing.

    Get PDF
    A novel in-line technique utilising pulsed terahertz radiation for direct measurement of the film coating thickness of individual tablets during the coating process was previously developed and demonstrated on a production-scale coater. Here, we use this technique to monitor the evolution of tablet film coating thickness and its inter-tablet variability during the coating process under a number of different process conditions that have been purposefully induced in the production-scale coating process. The changes that were introduced to the coating process include removing the baffles from the coater, adding uncoated tablets to the running process, halting the drum, blockage of spray guns and changes to the spray rate. The terahertz sensor was able to pick up the resulting changes in average coating thickness in the coating drum and we report the impact of these process changes on the resulting coating quality.This work was conducted with financial support from the UK Technology Strategy Board (AB293H). H.L. And J.A.Z. would like to acknowledge the Engineering and Physical Sciences Research Council (EP/L019922/1) and the Newton Trust Cambridge for research funding. J.A.Z. would like to thank Gonville & Caius College, Cambridge for a research fellowship. The authors acknowledge Colorcon Ltd. and Meggle AG for providing the excipients used in this study, Provel Ltd. (Bolton, UK) for the kind loan of the mixing equipment to disperse the coating polymer and Staffan Folestad (AstraZeneca) for useful discussions. Additional data related to this publication is available as a supplementary data to this publication as well as at the University of Cambridge data repository (https://www.repository.cam.ac.uk).This is the final version of the article. It first appeared from Wiley via http://dx.doi.org/10.1002/jps.2450

    Lesinurad, a novel, oral compound for gout, acts to decrease serum uric acid through inhibition of urate transporters in the kidney.

    Get PDF
    BackgroundExcess body burden of uric acid promotes gout. Diminished renal clearance of uric acid causes hyperuricemia in most patients with gout, and the renal urate transporter (URAT)1 is important for regulation of serum uric acid (sUA) levels. The URAT1 inhibitors probenecid and benzbromarone are used as gout therapies; however, their use is limited by drug-drug interactions and off-target toxicity, respectively. Here, we define the mechanism of action of lesinurad (Zurampic®; RDEA594), a novel URAT1 inhibitor, recently approved in the USA and Europe for treatment of chronic gout.MethodssUA levels, fractional excretion of uric acid (FEUA), lesinurad plasma levels, and urinary excretion of lesinurad were measured in healthy volunteers treated with lesinurad. In addition, lesinurad, probenecid, and benzbromarone were compared in vitro for effects on urate transporters and the organic anion transporters (OAT)1 and OAT3, changes in mitochondrial membrane potential, and human peroxisome proliferator-activated receptor gamma (PPARγ) activity.ResultsAfter 6 hours, a single 200-mg dose of lesinurad elevated FEUA 3.6-fold (p < 0.001) and reduced sUA levels by 33 % (p < 0.001). At concentrations achieved in the clinic, lesinurad inhibited activity of URAT1 and OAT4 in vitro, did not inhibit GLUT9, and had no effect on ABCG2. Lesinurad also showed a low risk for mitochondrial toxicity and PPARγ induction compared to benzbromarone. Unlike probenecid, lesinurad did not inhibit OAT1 or OAT3 in the clinical setting.ConclusionThe pharmacodynamic effects and in vitro activity of lesinurad are consistent with inhibition of URAT1 and OAT4, major apical transporters for uric acid. Lesinurad also has a favorable selectivity and safety profile, consistent with an important role in sUA-lowering therapy for patients with gout

    Postpneumonectomy syndrome: Surgical management and long-term results

    Get PDF
    ObjectivePostpneumonectomy syndrome is a rare syndrome of dynamic airway obstruction caused by extreme rotation and shift of the mediastinum after pneumonectomy, resulting in symptomatic central airway compression. We have treated this syndrome by mediastinal repositioning and placement of saline-filled prostheses into the pneumonectomy space. There is a paucity of outcome data for patients treated surgically, with only a single series of 11 patients previously reported. We analyzed our recent experience with treatment of this syndrome and report on the short and long-term outcomes and quality of life assessment of the largest series ever reported of patients treated by mediastinal repositioning.MethodsRecords were reviewed of all patients who underwent mediastinal repositioning for postpneumonectomy syndrome between January of 1992 and June of 2006. Long-term health-related quality of life was assessed by administration of the Saint George's Respiratory Questionnaire.ResultsThere were 18 patients (15 women and 3 men) with a median age of 44 years (range 14–67 years). Thirteen patients had undergone right pneumonectomy, and 5 patients had undergone left pneumonectomy. None of the patients in whom postpneumonectomy syndrome developed after left pneumonectomy had a right-sided aortic arch. Five patients had undergone pneumonectomy in childhood (age < 13 years). The median interval between pneumonectomy and mediastinal repositioning was 7.5 years (range 1.1–54.8 years). The median follow-up was 32 months (range 4–143 months). The operative mortality was 5.6% (1/18). Complications occurred in 5 patients (27.8%): pneumonia in 3 patients and acute respiratory distress syndrome in 2 patients. The median hospitalization was 6 days (range 3–155 days). Some 77% (10/13) of patients reported significant improvement in their breathing and overall state of health after surgery; 15.4% of patients (2/13) were somewhat better, and 7.7% of patients (1/13) had no improvement. No patients' condition was worse after surgery. All patients who reported improvement in their symptoms after surgery remained symptomatically improved at the time of the quality of life assessment. Some 92.3% (12/13) were not at all or only slightly limited in their social activities because of breathing problems, and 84.6% (11/13) were not at all or only slightly limited in their ability to work as a result of their physical health.ConclusionRepositioning of the mediastinum with placement of prostheses for postpneumonectomy syndrome can be performed with low mortality and morbidity. Surgical repositioning provides immediate and lasting symptomatic relief to patients in whom postpneumonectomy syndrome develops

    Nanoscale Evidence for Temperature-Induced Transient Rheology and Postseismic Fault Healing

    Get PDF
    Friction-generated heat and the subsequent thermal evolution control fault material properties and thus strength during the earthquake cycle. We document evidence for transient, nanoscale fault rheology on a high-gloss, light-reflective hematite fault mirror (FM). The FM cuts specularite with minor quartz from the Pleistocene El Laco Fe-ore deposit, northern Chile. Scanning and transmission electron microscopy data reveal that the FM volume comprises a2+ suboxides. Sub–5-nm-thick silica films encase hematite grains and connect to amorphous interstitial silica. Observations imply that coseismic shear heating (temperature \u3e1000 °C) generated transiently amorphous, intermixed but immiscible, and rheologically weak Fe-oxide and silica. Hematite regrowth in a fault-perpendicular thermal gradient, sintering, twinning, and a topographic network of nanometer-scale ridges from crystals interlocking across the FM surface collectively restrengthened fault material. Results reveal how temperature-induced weakening preconditions fault healing. Nanoscale transformations may promote subsequent strain delocalization and development of off-fault damage
    • …
    corecore