163 research outputs found

    Adam in Private: Secure and Fast Training of Deep Neural Networks with Adaptive Moment Estimation

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    Machine Learning (ML) algorithms, especially deep neural networks (DNN), have proven themselves to be extremely useful tools for data analysis, and are increasingly being deployed in systems operating on sensitive data, such as recommendation systems, banking fraud detection, and healthcare systems. This underscores the need for privacy-preserving ML (PPML) systems, and has inspired a line of research into how such systems can be constructed efficiently. We contribute to this line of research by proposing a framework that allows efficient and secure evaluation of full-fledged state-of-the-art ML algorithms via secure multi-party computation (MPC). This is in contrast to most prior works on PPML, which require advanced ML algorithms to be substituted with approximated variants that are ``MPC-friendly\u27\u27, before MPC techniques are applied to obtain a PPML algorithm. A drawback of the latter approach is that it requires careful fine-tuning of the combined ML and MPC algorithms, and might lead to less efficient algorithms or inferior quality ML (such as lower prediction accuracy). This is an issue for secure training of DNNs in particular, as this involves several arithmetic algorithms that are thought to be ``MPC-unfriendly\u27\u27, namely, integer division, exponentiation, inversion, and square root extraction. In this work, we propose secure and efficient protocols for the above seemingly MPC-unfriendly computations (but which are essential to DNN). Our protocols are three-party protocols in the honest-majority setting, and we propose both passively secure and actively secure with abort variants. A notable feature of our protocols is that they simultaneously provide high accuracy and efficiency. This framework enables us to efficiently and securely compute modern ML algorithms such as Adam (Adaptive moment estimation) and the softmax function ``as is\u27\u27, without resorting to approximations. As a result, we obtain secure DNN training that outperforms state-of-the-art three-party systems; our \textit{full} training is up to 6.76.7 times faster than just the \textit{online} phase of the recently proposed FALCON (Wagh et al. at PETS\u2721) on the standard benchmark network for secure training of DNNs. To further demonstrate the scalability of our protocols, we perform measurements on real-world DNNs, AlexNet and VGG16, which are complex networks containing millions of parameters. The performance of our framework for these networks is up to a factor of about 121412\sim 14 faster for AlexNet and 464846\sim 48 faster for VGG16 to achieve an accuracy of 70%70\% and 75%75\%, respectively, when compared to FALCON

    Molecular deformation in the O 1s[-1] 2πu excited states of CO2 probed by the triple-differential measurement of fragment ions

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    Measurement of mass-, energy-, and angle-resolved fragment ions reveals that the β value for C+ with kinetic energy ≥~3 eV is ∼0.9 in the region of the O 1s→2πu excitation and that the β value for O+ with kinetic energy ≥~4 eV varies from -0.23 to -0.57 across the O 1s→2πu resonance. These findings postulate that the CO2 molecule excited to the lower branch of the vibronically split O 1s[-1]2πu excited states deforms into a bent geometry while the molecule excited to the higher branch remains in a linear geometry

    Genetic Characterization of Conserved Charged Residues in the Bacterial Flagellar Type III Export Protein FlhA

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    For assembly of the bacterial flagellum, most of flagellar proteins are transported to the distal end of the flagellum by the flagellar type III protein export apparatus powered by proton motive force (PMF) across the cytoplasmic membrane. FlhA is an integral membrane protein of the export apparatus and is involved in an early stage of the export process along with three soluble proteins, FliH, FliI, and FliJ, but the energy coupling mechanism remains unknown. Here, we carried out site-directed mutagenesis of eight, highly conserved charged residues in putative juxta- and trans-membrane helices of FlhA. Only Asp-208 was an essential acidic residue. Most of the FlhA substitutions were tolerated, but resulted in loss-of-function in the ΔfliH-fliI mutant background, even with the second-site flhB(P28T) mutation that increases the probability of flagellar protein export in the absence of FliH and FliI. The addition of FliH and FliI allowed the D45A, R85A, R94K and R270A mutant proteins to work even in the presence of the flhB(P28T) mutation. Suppressor analysis of a flhA(K203W) mutation showed an interaction between FlhA and FliR. Taken all together, we suggest that Asp-208 is directly involved in PMF-driven protein export and that the cooperative interactions of FlhA with FlhB, FliH, FliI, and FliR drive the translocation of export substrate

    An energy transduction mechanism used in bacterial flagellar type III protein export

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    Flagellar proteins of bacteria are exported by a specific export apparatus. FliI ATPase forms a complex with FliH and FliJ and escorts export substrates from the cytoplasm to the export gate complex, which is made up of six membrane proteins. The export gate complex utilizes proton motive force across the cytoplasmic membrane for protein translocation, but the mechanism remains unknown. Here we show that the export gate complex by itself is a proton–protein antiporter that uses the two components of proton motive force, Δψ and ΔpH, for different steps of the protein export process. However, in the presence of FliH, FliI and FliJ, a specific binding of FliJ with an export gate membrane protein, FlhA, is brought about by the FliH–FliI complex, which turns the export gate into a highly efficient, Δψ-driven protein export apparatus

    Fluid Mechanics in Dentinal Microtubules Provides Mechanistic Insights into the Difference between Hot and Cold Dental Pain

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    Dental thermal pain is a significant health problem in daily life and dentistry. There is a long-standing question regarding the phenomenon that cold stimulation evokes sharper and more shooting pain sensations than hot stimulation. This phenomenon, however, outlives the well-known hydrodynamic theory used to explain dental thermal pain mechanism. Here, we present a mathematical model based on the hypothesis that hot or cold stimulation-induced different directions of dentinal fluid flow and the corresponding odontoblast movements in dentinal microtubules contribute to different dental pain responses. We coupled a computational fluid dynamics model, describing the fluid mechanics in dentinal microtubules, with a modified Hodgkin-Huxley model, describing the discharge behavior of intradental neuron. The simulated results agreed well with existing experimental measurements. We thence demonstrated theoretically that intradental mechano-sensitive nociceptors are not “equally sensitive” to inward (into the pulp) and outward (away from the pulp) fluid flows, providing mechanistic insights into the difference between hot and cold dental pain. The model developed here could enable better diagnosis in endodontics which requires an understanding of pulpal histology, neurology and physiology, as well as their dynamic response to the thermal stimulation used in dental practices

    Inhibitory Effects of Prior Low-dose X-irradiation on Ischemia-reperfusion Injury in Mouse Paw

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    We have reported that low-dose, unlike high-dose, irradiation enhanced antioxidation function and reduced oxidative damage. On the other hand, ischemia-reperfusion injury is induced by reactive oxygen species. In this study, we examined the inhibitory effects of prior low-dose X-irradiation on ischemia-reperfusion injury in mouse paw. BALB/c mice were irradiated by sham or 0.5 Gy of X-ray. At 4 hrs after irradiation, the left hind leg was bound 10 times with a rubber ring for 0.5, 1, or 2 hrs and the paw thickness was measured. Results show that the paw swelling thickness by ischemia for 0.5 hr was lower than that for 2 hrs. At 1 hr after reperfusion from ischemia for 1 hr, superoxide dismutase activity in serum was increased in those mice which received 0.5 Gy irradiation and in the case of the ischemia for 0.5 or 1 hr, the paw swelling thicknesses were inhibited by 0.5 Gy irradiation. In addition, interstitial edema in those mice which received 0.5 Gy irradiation was less than that in the mice which underwent by sham irradiation. These findings suggest that the ischemia-reperfusion injury is inhibited by the enhancement of antioxidation function by 0.5 Gy irradiation

    Proteomic Analysis of Growth Phase-Dependent Expression of Legionella pneumophila Proteins Which Involves Regulation of Bacterial Virulence Traits

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    Legionella pneumophila, which is a causative pathogen of Legionnaires' disease, expresses its virulent traits in response to growth conditions. In particular, it is known to become virulent at a post-exponential phase in vitro culture. In this study, we performed a proteomic analysis of differences in expression between the exponential phase and post-exponential phase to identify candidates associated with L. pneumophila virulence using 2-Dimentional Fluorescence Difference Gel Electrophoresis (2D-DIGE) combined with Matrix-Assisted Laser Desorption/Ionization–Mass Spectrometry (MALDI-TOF-MS). Of 68 identified proteins that significantly differed in expression between the two growth phases, 64 were up-regulated at a post-exponential phase. The up-regulated proteins included enzymes related to glycolysis, ketone body biogenesis and poly-3-hydroxybutyrate (PHB) biogenesis, suggesting that L. pneumophila may utilize sugars and lipids as energy sources, when amino acids become scarce. Proteins related to motility (flagella components and twitching motility-associated proteins) were also up-regulated, predicting that they enhance infectivity of the bacteria in host cells under certain conditions. Furthermore, 9 up-regulated proteins of unknown function were found. Two of them were identified as novel bacterial factors associated with hemolysis of sheep red blood cells (SRBCs). Another 2 were found to be translocated into macrophages via the Icm/Dot type IV secretion apparatus as effector candidates in a reporter assay with Bordetella pertussis adenylate cyclase. The study will be helpful for virulent analysis of L. pneumophila from the viewpoint of physiological or metabolic modulation dependent on growth phase

    Four whole-istic aspects of schistosome granuloma biology: fractal arrangement, internal regulation, autopoietic component and closure

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    This paper centers on some whole-istic organizational and functional aspects of hepatic Schistosoma mansoni granuloma, which is an extremely complex system. First, it structurally develops a collagenic topology, originated bidirectionally from an inward and outward assembly of growth units. Inward growth appears to be originated from myofibroblasts derived from small portal vessel around intravascular entrapped eggs, while outward growth arises from hepatic stellate cells. The auto-assembly of the growth units defines the three-dimensional scaffold of the schistosome granulomas. The granuloma surface irregularity and its border presented fractal dimension equal to 1.58. Second, it is internally regulated by intricate networks of immuneneuroendocrine stimuli orchestrated by leptin and leptin receptors, substance P and Vasoactive intestinal peptide. Third, it can reach the population of ± 40,000 cells and presents an autopoietic component evidenced by internal proliferation (Ki-67+ Cells), and by expression of c-Kit+ Cells, leptin and leptin receptor (Ob-R), granulocyte-colony stimulating factor (G-CSF-R), and erythropoietin (Epo-R) receptors. Fourth, the granulomas cells are intimately connected by pan-cadherins, occludin and connexin-43, building a state of closing (granuloma closure). In conclusion, the granuloma is characterized by transitory stages in such a way that its organized structure emerges as a global property which is greater than the sum of actions of its individual cells and extracellular matrix components

    Foot orthoses in the treatment of symptomatic midfoot osteoarthritis using clinical and biomechanical outcomes: a randomised feasibility study.

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    Objectives: This randomised feasibility study aimed to examine the clinical and biomechanical effects of functional foot orthoses (FFO) in the treatment of midfoot osteoarthritis (OA) and the feasibility of conducting a full randomised-controlled trial. Methods: Participants with painful, radiographically confirmed midfoot OA were recruited and randomised to receive either FFO or a sham control orthosis. Feasibility measures included recruitment and attrition rates, practicality of blinding and adherence rates. Clinical outcome measures were change from baseline to 12 weeks for severity of pain (numerical rating scale), foot function (Manchester Foot Pain and Disability Index) and patient global impression of change scale. To investigate the biomechanical effect of foot orthoses, in-shoe foot kinematics and plantar pressures were evaluated at 12 weeks. Results: Of the 119 participants screened, 37 were randomised and 33 completed the study (FFO=18, sham=15). Compliance with foot orthoses and blinding of the intervention was achieved in three-quarters of the group. Both groups reported improvements in pain, function and global impression of change; the FFO group reporting greater improvements compared to the sham group. The biomechanical outcomes indicated the FFO group inverted the hindfoot and increased midfoot maximum plantar force compared to the sham group. Conclusions: The present findings suggest FFOs worn over 12 weeks may provide detectable clinical and biomechanical benefits compared to sham orthoses. This feasibility study provides useful clinical, biomechanical and statistical information for the design and implementation of a definitive randomised-controlled trial to evaluate the effectiveness of FFO in treating painful midfoot OA
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