147 research outputs found

    Achieving Differential Privacy with Bias-Control Limited Source

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    In the design of differentially private mechanisms, it’s usually assumed that a uniformly random source is available. However, in many situations it seems unrealistic, and one must deal with various imperfect random sources. Dodis et al. (CRYPTO’12) presented that differential privacy can be achieved with Santha-Vazirani (SV) source via adding a stronger property called SV-consistent sampling and left open question if differential privacy is possible with more realistic (i.e., less structured) sources. A new source, called Bias-Control Limited (BCL) source, introduced by Dodis (ICALP’01), is more realistic. It can be considered as a generalization of the SV and sequential bit-fixing sources. Unfortunately, the natural extension of SV-consistent sampling to the BCL source is hopeless to achieve differential privacy, mainly because SV-consistent sampling requires “consecutive” strings, while some strings can’t be generated from “non-trivial” BCL source. Motivated by this problem, we introduce a new appealing property, called compact BCL-consistent sampling, the degeneration of which is different from SV-consistent sampling shown by Dodis et al. (CRYPTO’12). We prove that if the mechanism based on the BCL source satisfies this property, then it’s differentially private. Even if the BCL source is degenerated into the SV-source, our proof is much more intuitive and simpler than that of Dodis et al. Further, we construct explicit mechanisms using a new truncation technique as well as arithmetic coding. We also propose its concrete results for differential privacy and utility. While the results of Dodis and Yao (CRYPTO’15) imply that if there exist differentially private mechanisms for imperfect randomness, then the parameters should have some constraints, we show an explicit construction of such mechanisms, whose parameters match the prior constraints

    Non-Malleable Extractors with Shorter Seeds and Their Applications

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    Motivated by the problem of how to communicate over a public channel with an active adversary, Dodis and Wichs (STOC’09) introduced the notion of a non-malleable extractor. A non-malleable extractor nmExt : {0, 1}^n ×{0, 1}^d \rightarrow {0, 1}^m takes two inputs, a weakly random W and a uniformly random seed S, and outputs a string which is nearly uniform, given S as well as nmExt(W,A(S)), for an arbitrary function A with A(S) = S. In this paper, by developing the combination and permutation techniques, we improve the error estimation of the extractor of Raz (STOC’05), which plays an extremely important role in the constraints of the non-malleable extractor parameters including seed length. Then we present improved explicit construction of non-malleable extractors. Though our construction is the same as that given by Cohen, Raz and Segev (CCC’12), the parameters are improved. More precisely, we construct an explicit (1016, 1/2)-non-malleable extractor nmExt : {0, 1}^n ×{0, 1}^d \rightarrow {0, 1} with n = 210 and seed length d = 19, while Cohen et al. showed that the seed length is no less than 46/63 +66. Therefore, our method beats the condition “2.01 · log n \leq d \leq n” proposed by Cohen et al., since d is just 1.9 · log n in our construction. We also improve the parameters of the general explicit construction given by Cohen et al. Finally, we give their applications to privacy amplification

    Effects of oxygen enrichment on diesel spray flame soot formation in O<sub>2</sub>/Ar atmosphere

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    In this study, diesel spray combustion at oxygen-enriched conditions (oxygen volume fraction of 21–70 %) with argon dilution is experimentally investigated in a constant-volume combustion chamber. Optical diagnostics are employed to study flame development, stabilization, and soot formation at oxygen-enriched conditions. To further verify the experimental observations, two-stage Lagrangian simulations are used to analyze the effects of oxygen on the formation and oxidation of soot precursors, polycyclic aromatic hydrocarbons. Results show that replacing nitrogen in air by argon leads to a 50 % reduction of the flame lift-off length, an increased soot flame temperature by 300 K, and higher soot concentrations. Flame morphology and structure still follow the classic conventional diesel combustion model in the oxygen range of 21–40 %, while changes are observed when oxygen levels are higher than 50 %. The width and length of the soot flame are shortened, and chemiluminescence from intermediate species like CO dominates the flame natural luminosity at the spray head, where the flame temperature reaches near 3000 K. Soot reduction mechanisms at high-degree oxygen-enrichment conditions are investigated. The intrinsic mixing-limited combustion of diesel sprays leads to unavoidable fuel-rich areas locally, but the shortened flame lift-off length and sufficient oxygen supply confines soot-forming conditions to a smaller, upstream region. The residence time of fuel parcels in this confined soot-forming area is shortened due to the larger local spray velocity. Thereafter, fuel parcels enter a high-temperature fuel-lean region, where the formed soot is oxidized rapidly.</p

    Effects of oxygen enrichment on diesel spray flame soot formation in O<sub>2</sub>/Ar atmosphere

    Get PDF
    In this study, diesel spray combustion at oxygen-enriched conditions (oxygen volume fraction of 21–70 %) with argon dilution is experimentally investigated in a constant-volume combustion chamber. Optical diagnostics are employed to study flame development, stabilization, and soot formation at oxygen-enriched conditions. To further verify the experimental observations, two-stage Lagrangian simulations are used to analyze the effects of oxygen on the formation and oxidation of soot precursors, polycyclic aromatic hydrocarbons. Results show that replacing nitrogen in air by argon leads to a 50 % reduction of the flame lift-off length, an increased soot flame temperature by 300 K, and higher soot concentrations. Flame morphology and structure still follow the classic conventional diesel combustion model in the oxygen range of 21–40 %, while changes are observed when oxygen levels are higher than 50 %. The width and length of the soot flame are shortened, and chemiluminescence from intermediate species like CO dominates the flame natural luminosity at the spray head, where the flame temperature reaches near 3000 K. Soot reduction mechanisms at high-degree oxygen-enrichment conditions are investigated. The intrinsic mixing-limited combustion of diesel sprays leads to unavoidable fuel-rich areas locally, but the shortened flame lift-off length and sufficient oxygen supply confines soot-forming conditions to a smaller, upstream region. The residence time of fuel parcels in this confined soot-forming area is shortened due to the larger local spray velocity. Thereafter, fuel parcels enter a high-temperature fuel-lean region, where the formed soot is oxidized rapidly.</p

    Enhancing skill learning with dual-user haptic feedback: insights from a task-specific approach

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    Introduction: This study was to examine whether inter-user haptic feedback would have a differential impact on skill acquisition based on the nature of the surgical task involved. Specifically, we hypothesized that haptic feedback would facilitate target orientation more than cutting tasks in the context of laparoscopic surgery.Methods: Ten novice participants were recruited and assigned to one of two training groups. Each group underwent six half-hour training sessions dedicated to laparoscopic pattern-cutting tasks. In the haptic group, five participants received expert guidance during the training sessions, whereas the remaining five participants in the control group engaged in self-practice. All trials were recorded on video, enabling a comparative analysis of task performance between the participants’ left hand (target manipulation) and right hand (cutting task). Additionally, the number of haptic feedback instances provided to the trainees in the haptic group was recorded.Results: Practice led to a reduction in total task time, grasping time, and cutting errors. However, no significant differences were observed between the two training groups, except for the grasping time, where haptic feedback significantly reduced the grasping time compared to the control group. Moreover, the frequency of haptic feedback instances provided to the trainees was notably higher for the grasping than for the cutting task.Discussion: Our study suggests that haptic feedback has a more substantial impact on orientation tasks than on cutting tasks in laparoscopic surgery training. However, we acknowledge that a larger sample size would provide a more robust evaluation of this effect

    Transcutaneous Electrical Acupoint Stimulation Improves the Postoperative Quality of Recovery and Analgesia after Gynecological Laparoscopic Surgery: A Randomized Controlled Trial

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    Background. We conducted this prospective, randomized, double-blind, placebo-controlled study to evaluate the effects of transcutaneous electric acupoint stimulation (TEAS) on the quality of recovery (QoR) and postoperative analgesia after gynecological laparoscopic surgery. Methods. 74 American Society of Anesthesiologists physical status (ASA) I or II patients undergoing gynecological laparoscopic surgery were randomly allocated to TEAS or control groups. The primary outcome was the quality of recovery, which was assessed on the day before surgery and 24 h after surgery using a 40-item questionnaire. Secondary outcomes included postoperative pain scores, the incidence of postoperative nausea and vomiting (PONV), duration of postanesthesia care unit (PACU) stay, and patient’s satisfaction. Results. The TEAS group had higher QoR scores than control group upon 24 h after surgery (177 versus 165; P<0.001). Compared with the control group, postoperative pain scores and the cumulative number of opioids administered were lower in the TEAS group patients (P=0.04). TEAS reduced the incidence of PONV and dizziness, as well as duration of PACU stay. Simultaneously, the patient’s satisfaction scores were higher in the TEAS group (P=0.002). Conclusion. Preoperative TEAS enhances QoR, improves postoperative analgesia and patient’s satisfaction, alleviates postoperative side effects, and accelerates discharge after general anesthesia for gynecological laparoscopic surgery

    Dl-3-n-Butylphthalide Reduces Cognitive Deficits and Alleviates Neuropathology in P301S Tau Transgenic Mice

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    Alzheimer’s disease (AD) is a destructive and burdensome neurodegenerative disease, one of the most common characteristics of which are neurofibrillary tangles (NFTs) that are composed of abnormal tau protein. Animal studies have suggested that dl-3-n-butylphthalide (dl-NBP) alleviates cognitive impairment in mouse models of APP/PS1 and SAMP8. However, the underlying mechanisms related to this remain unclear. In this study, we examined the effects of dl-NBP on learning and memory in P301S transgenic mice, which carry the human tau gene with the P301S mutation. We found that dl-NBP supplementation effectively improved behavioral deficits and rescued synaptic loss in P301S tau transgenic mice, compared with vehicle-treated P301S mice. Furthermore, we also found that it markedly inhibited the hyperphosphorylated tau at the Ser262 site and decreased the activity of MARK4, which was associated with tau at the Ser262 site. Finally, dl-NBP treatment exerted anti-inflammatory effects and reduced inflammatory responses in P301S mice. In conclusion, our results provide evidence that dl-NBP has a promising potential for the therapy of tauopathies, including AD

    Tuberous sclerosis complex exhibits a new renal cystogenic mechanism

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    Tuberous sclerosis complex (TSC) is a tumor predisposition syndrome with significant renal cystic and solid tumor disease. While the most common renal tumor in TSC, the angiomyolipoma, exhibits a loss of heterozygosity associated with disease, we have discovered that the renal cystic epithelium is composed of type A intercalated cells that have an intact Tsc gene that have been induced to exhibit Tsc‐mutant disease phenotype. This mechanism appears to be different than that for ADPKD. The murine models described here closely resemble the human disease and both appear to be mTORC1 inhibitor responsive. The induction signaling driving cystogenesis may be mediated by extracellular vesicle trafficking.TSC renal cystic disease develops in about half of the patients. The disease appears to caused by an induction mechanism such that a small population of mutant cells can cause significant renal cystic disease comprised of mostly genetically normal cells.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147796/1/phy213983.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147796/2/phy213983_am.pd
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