30 research outputs found

    FSPVDsse: A Forward Secure Publicly Verifiable Dynamic SSE scheme

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    A symmetric searchable encryption (SSE) scheme allows a client (data owner) to search on encrypted data outsourced to an untrusted cloud server. The search may either be a single keyword search or a complex query search like conjunctive or Boolean keyword search. Information leakage is quite high for dynamic SSE, where data might be updated. It has been proven that to avoid this information leakage an SSE scheme with dynamic data must be forward private. A dynamic SSE scheme is said to be forward private, if adding a keyword-document pair does not reveal any information about the previous search result with that keyword. In SSE setting, the data owner has very low computation and storage power. In this setting, though some schemes achieve forward privacy with honest-but-curious cloud, it becomes difficult to achieve forward privacy when the server is malicious, meaning that it can alter the data. Verifiable dynamic SSE requires the server to give a proof of the result of the search query. The data owner can verify this proof efficiently. In this paper, we have proposed a generic publicly verifiable dynamic SSE (DSSE) scheme that makes any forward private DSSE scheme verifiable without losing forward privacy. The proposed scheme does not require any extra storage at owner-side and requires minimal computational cost as well for the owner. Moreover, we have compared our scheme with the existing results and show that our scheme is practical.Comment: 17 pages, Published in ProvSec 201

    Evaluating WRF-GC v2.0 predictions of boundary layer height and vertical ozone profile during the 2021 TRACER-AQ campaign in Houston, Texas

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    The TRacking Aerosol Convection ExpeRiment – Air Quality (TRACER-AQ) campaign probed Houston air quality with a comprehensive suite of ground-based and airborne remote sensing measurements during the intensive operating period in September 2021. Two post-frontal high-ozone episodes (6–11 and 23–26 September) were recorded during the aforementioned period. In this study, we evaluated the simulation of the planetary boundary layer (PBL) height and the vertical ozone profile by a high-resolution (1.33 km) 3-D photochemical model, the Weather Research and Forecasting (WRF)-driven GEOS-Chem (WRF-GC). We evaluated the PBL heights with a ceilometer at the coastal site La Porte and the airborne High Spectral Resolution Lidar 2 (HSRL-2) flying over urban Houston and adjacent waters. Compared with the ceilometer at La Porte, the model captures the diurnal variations in the PBL heights with a very strong temporal correlation (R&gt;0.7) and ±20 % biases. Compared with the airborne HSRL-2, the model exhibits a moderate to strong spatial correlation (R=0.26–0.68), with ±20 % biases during the noon and afternoon hours during ozone episodes. For land–water differences in PBL heights, the water has shallower PBL heights compared to land. The model predicts larger land–water differences than the observations because the model consistently underestimates the PBL heights over land compared to water. We evaluated vertical ozone distributions by comparing the model against vertical measurements from the TROPospheric OZone lidar (TROPOZ), the HSRL-2, and ozonesondes, as well as surface measurements at La Porte from a model 49i ozone analyzer and one Continuous Ambient Monitoring Station (CAMS). The model underestimates free-tropospheric ozone (2–3 km aloft) by 9 %–22 % but overestimates near-ground ozone (&lt;50 m aloft) by 6 %-39 % during the two ozone episodes. Boundary layer ozone (0.5–1 km aloft) is underestimated by 1 %–11 % during 8–11 September but overestimated by 0 %–7 % during 23–26 September. Based on these evaluations, we identified two model limitations, namely the single-layer PBL representation and the free-tropospheric ozone underestimation. These limitations have implications for the predictivity of ozone's vertical mixing and distribution in other models.</p

    Positively selected amino acid replacements within the RuBisCO enzyme of oak trees are associated with ecological adaptations

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    Phylogenetic analysis by maximum likelihood (PAML) has become the standard approach to study positive selection at the molecular level, but other methods may provide complementary ways to identify amino acid replacements associated with particular conditions. Here, we compare results of the decision tree (DT) model method with ones of PAML using the key photosynthetic enzyme RuBisCO as a model system to study molecular adaptation to particular ecological conditions in oaks (Quercus). We sequenced the chloroplast rbcL gene encoding RuBisCO large subunit in 158 Quercus species, covering about a third of the global genus diversity. It has been hypothesized that RuBisCO has evolved differentially depending on the environmental conditions and leaf traits governing internal gas diffusion patterns. Here, we show, using PAML, that amino acid replacements at the residue positions 95, 145, 251, 262 and 328 of the RuBisCO large subunit have been the subject of positive selection along particular Quercus lineages associated with the leaf traits and climate characteristics. In parallel, the DT model identified amino acid replacements at sites 95, 219, 262 and 328 being associated with the leaf traits and climate characteristics, exhibiting partial overlap with the results obtained using PAML

    Quantitative and qualitative measurement of styrene in Tabriz Petrochemical Complex

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    Background and aims   Beside the vast usages of styrene in different industries, this compound can be considered as an important organic air pollutant. Styrene, in one hand, can adversely affect on workers and on the other hands can cause air pollution in the environment. In this study, Tabriz Petrochemical Complex was selected for evaluation of styrene.   Methods   Measurements were performed separately in production lines of olephin and styrene and sampling sites were selected randomly in both olephine and styrene lines. For evaluation of styrene, occupational sampling was performed based on method number 834 recommended in the book &quot;Air sampling analysis&quot;. The method was extended using some correction factors. Sampling  process was performed in seasons Summer and Autumn. To draw isoline curves of Pollution,   Surfer software version 504 was used.    Results & Conclusion   The results showed that, there were no significant difference between concentration of pollutants and seasons. Agreement between styrene concentration and prailing winds showed a significant difference between styrene and prailing winds.  

    Feasibility of the use of ( ZnxHg(1-x)Te ternary compound as a spectrometer of nuclear radiations

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    In this paper in order to achieve a suitable spectrometer for nuclear radiation detection at room temperature, effect of adding the element Hg to binary compound semiconductor ZnTe was studied completely. Electronic structure and transport properties of ternary compound semiconductor ZnxHg(1-x)Te (ZHT) simulated using ABINIT as a computational code based on density functional theory. According to this simulation the range of x&ge;0.8 was selected. This simulations including good response function compared to CdTe simulated by using MCNP as a computational code, shows that ZHT in the above range is a suitable nuclear spectrometer at room temperature

    Evaluating subway drivers’ exposure to whole body vibration based on Basic and VDV methods (with ISO 2631-1 standard)

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    Introduction: Whole body vibration occurs when human is on a vibrating surface and the vibration influences parts of the body which are far from the contacted part. Up to now, various health-related problems due to whole body vibration have been reported, including back pain, sciatica, gastrointestinal problems, genital problems and hearing impairment. In the present research, vibration was measured about 2000 minutes in 23 train of 4 active lines of Tehran metro in order to determine the rate of subway drivers’ exposed to whole body vibration. . Material and Method: Vibration meter and SVAN 958 analyzer, made by Svantek company, were utilized for measuring the whole body vibration. The level of weighted r.m.s acceleration for each axis, the combination of axes, peak factor, VDV and other common exiting ratios in the standard were measured and calculated according to ISO 2631-1. . Result: Findings showed that according to Basic method drivers exposure to vibration is less than the lowest value of health guide critical region (<0.45m/s2). However, based on Vibration Dose Valuation (VDV), the exposure of 12 cases were higher than the lowest value (<8.5 m/s1.75) and only 11 cases were lower than the mentioned amount. . Conclusion: Investigation of the result obtained from Basic method and VDV method manifested different amounts of vibration exposure in a way that VDV predicts higher level of risk, compared to basic method. The results shows that some presented indicators can not presented the safe zone in human vibration evaluations

    Study of noise-induced hearing loss by distortion product otoacoustic emissions

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    Background and objective: Noise-induced hearing loss remains as the most common problem in industrial societies. This research was conducted to study noise-induced hearing loss by distortion-product otoacoustic emissions (DPOAEs). Methods: This study was carried out on 12 male New Zealand White rabbits including control (exposed to noise) and experimental (exposed to 95 dBA SPL white noise at 500-8000 Hz for 8 hours per day during 5 consecutive days). DPOAEs were measured and compared in days zero (before exposure as baseline), eighth (experimental: An hour after latest exposure to noise for Temporary Threshold Shifts: TTS), tenth (experimental: 48 hours after latest exposure to noise for Permanent Threshold Shifts: PTSs). Findings: The most and the least values of TTSs, PTSs and DPOAEs amplitude in noise group were correspond to frequencies of 5888.50 Hz and 588.00 Hz, respectively (p&lt;0.05). There was a significant difference between TTSs, PTSs and DPOAEs amplitude at different frequencies in right and left ear of noise group (p&lt;0.05). This difference was related to frequency 5888.5 Hz in each of right and left ear of noise group compared to other frequencies in same ear (p&lt;0.05). There were not any significant difference between TTSs, PTSs and DPOAEs amplitude of right and left ear of noise group at different frequencies (p&gt;0.05). Conclusion: Excessive noise can cause TTSs and noise-induced PTSs and decreased DPOAEs amplitudes. Therefore, DPOAEs can be attributed as a useful tool for study of noise-induced hearing loss

    An Efficient Graphene Quantum Dots-Based Electrochemical Cytosensor for the Sensitive Recognition of CD123 in Acute Myeloid Leukemia Cells

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    Leukemia stem cells (LSCs) are suitable candidates to be deployed for the diagnosis and therapy of acute myeloid leukemia (AML) patients. In this study, a novel electrochemical cytosensor was designed for the sensitive detection and quantification of KG1a cells as a model of LSCs. The developed cytosensor was based on the overexpression of cell surface protein CD123 by leukemia KG1a cells. For this purpose, the glassy carbon electrode was modified by graphene quantum dots (GQDs), Au nanoparticles, streptavidin coated AuNPs, biotinylated CD123 antibody and target cells. The dense loading of CD123 antibody and electrical enhancement on the modified electrode were carried out using GQDs, this resulting in a sensitive detection of CD123 positive cells within KG1a cells. Step by step preparation of the nanomaterial-based cytosensor and its optimization steps were confirmed by different electrochemical techniques. The field emission scanning electron microscopy (FE-SEM) images also confirmed the proper attachment of the materials and the cells on the surface of the modified electrode. The linear detection range (LDR) and limit of detection (LOD) of the developed electrochemical biosensor were recorded as 1 cell/mL and 1-25 cells/mL, respectively, which is remarkable. Importantly, the present findings are precise and highly selective in the presence of other leukemia cells (NB4, HL60, and U937 cells). Further, the versatility and accuracy of the proposed cytosensor were evaluated using clinical samples. We believe that the cytosensor proposed in this study has the potential to serve as a next generation sensor for the early detection of leukemia stem cells
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