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1.
Sensors (Basel) ; 20(5)2020 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-32164220

RESUMO

Different from the traditional healthcare field, Medical Cyber Physical Systems (MCPS) rely more on wireless wearable devices and medical applications to provide better medical services. The secure storage and sharing of medical data are facing great challenges. Blockchain technology with decentralization, security, credibility and tamper-proof is an effective way to solve this problem. However, capacity limitation is one of the main reasons affecting the improvement of blockchain performance. Certificateless aggregation signature schemes can greatly tackle the difficulty of blockchain expansion. In this paper, we describe a two-layer system model in which medical records are stored off-blockchain and shared on-blockchain. Furthermore, a multi-trapdoor hash function is proposed. Based on the proposed multi-trapdoor hash function, we present a certificateless aggregate signature scheme for blockchain-based MCPS. The purpose is to realize the authentication of related medical staffs, medical equipment, and medical apps, ensure the integrity of medical records, and support the secure storage and sharing of medical information. The proposed scheme is highly computationally efficient because it does not use bilinear maps and exponential operations. Many certificateless aggregate signature schemes without bilinear maps in Internet of things (IoT) have been proposed in recent years, but they are not applied to the medical field, and they do not consider the security requirements of medical data. The proposed scheme in this paper has high computing and storage efficiency, while meeting the security requirements in MCPS.

2.
J Med Syst ; 44(2): 52, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31915982

RESUMO

With the rapid development of technologies such as artificial intelligence, blockchain, cloud computing, and big data, Medical Cyber Physical Systems (MCPS) are increasingly demanding data security, while cloud storage solves the storage problem of complex medical data. However, it is difficult to realize data security sharing. The decentralization feature of blockchain is helpful to solve the problem that the secure authentication process is highly dependent on the trusted third party and implement data security transmission. In this paper, the blockchain technology is used to describe the security requirements in authentication process, and a network model of MCPS based on blockchain is proposed. Through analysis of medical data storage architecture, it can ensure that data can't be tampered and untrackable. In the security authentication phase, bilinear mapping and intractable problems can be used to solve the security threat in the authentication process of medical data providers and users. It can avoid the credibility problem of the trusted third party, and also can realize the ?thyc=10?>two-way authentication between the hospital and blockchain node. Then, BAN logic is used to analyze security protocols, and formal analysis and comparison of security protocols are also made. The results show that the MCPS based on blockchain not only realizes medical treatment data sharing, but also meet the various security requirements in the security authentication phase. In addition, the storage and computing overhead costs is ideal. Therefore, the proposed scheme is more suitable for secure sharing of medical big data.

3.
Sensors (Basel) ; 19(19)2019 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-31569570

RESUMO

With the rapid development of the Internet of Things (IoT), it becomes challenging to ensure its security. Identity authentication and integrity verification can be achieved by secure hash functions and digital signature algorithms for IoT applications. In order to solve the issues of bandwidth limitation and computational efficiency of secure communication in IoT applications, an aggregate signature scheme based on multi- trapdoor hash function is proposed in this paper. Firstly, to prevent key exposition, based on the elliptic curve discrete logarithm problem (ECDLP), we constructed a double trapdoor hash function (DTH) and proved its reliability. Secondly, the multi-trapdoor hash function (MTH) based on DTH is presented. Finally, an MTH-based aggregate signature scheme (MTH-AS) with constant signature length is proposed. Based on the assumption of ECDLP, the proposed scheme is proven unforgeable against adaptive chosen message attacks with the Forking Lemma. Different from the most signature schemes with bilinear mapping, the proposed scheme has higher computational efficiency and shorter aggregate signature length. Moreover, it is independent of the number of signers. Security analysis and performance evaluation has revealed that the proposed scheme is an ideal solution for secure IoT applications with limited computing power, storage capacity, or limited bandwidth, such as wireless sensor networks, vehicular ad hoc networks, or healthcare sensor networks.


Assuntos
Algoritmos , Segurança Computacional , Privacidade , Redes de Comunicação de Computadores , Humanos
4.
J Breast Cancer ; 22(1): 131-140, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30941240

RESUMO

When faced with a case of bilateral breast cancer (BBC), understanding how to differentiate bilateral primary breast cancer from contralateral metastatic breast cancer is essential for treatment, but clear identification criteria have not been established to date. Diverse events play different roles in the therapy and prognosis of BBC; hence, it is of great significance to detect a more comprehensive and convincing technique to make an accurate differential diagnosis. We report a rare case of synchronous BBC in a 61-year-old Chinese woman. Based on her clinical and pathological features and the use of whole exome sequencing and cancer genome analysis, we concluded that the patient developed contralateral metastatic breast cancer which metastasized from left to right. Therefore, together with clinical, pathological and cancer genomics information, we could precisely define the origin and evolution of BBC.

5.
Materials (Basel) ; 12(2)2019 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-30634680

RESUMO

Near- α titanium alloys have extensive applications in high temperature structural components of aircrafts. To manufacture complex-shaped titanium alloy panel parts with desired microstructure and good properties, an innovative low-cost hot stamping process for titanium alloy was studied in this paper. Firstly, a series of hot tensile tests and Scanning Electron Microscope (SEM) observations were performed to investigate hot deformation characteristics and identify typical microstructural evolutions. The optimal forming temperature range is determined to be from 750 °C to 900 °C for hot stamping of TA15. In addition, a unified mechanisms-based material model for TA15 titanium alloy based on the softening mechanisms of recrystallization and damage was established, which enables to precisely predict stress-strain behaviors and potentially to be implemented into Finite Element (FE) simulations for designing the reasonable processing window of structural parts for the aerospace industry.

6.
Oncotarget ; 8(60): 101087-101094, 2017 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-29254147

RESUMO

The aim of this study was to determine the predictive value of the clinical and histopathological characteristics of estrogen receptor (ER)-positive patients treated with dose-dense paclitaxel/carboplatin neoadjuvant chemotherapy (NCT). Pathological complete response (pCR) and the change in tumor size between pre- and post-NCT were used to evaluate the tumor response.85 ER-positive breast cancer patients who were treated with dose-dense (biweekly) paclitaxel/carboplatin NCT were analyzed with respect to the expression of progesterone receptor (PgR), Tau, Ki67, human epidermal growth factor receptor 2 (HER2), and Bcl-2 by immunohistochemistry (IHC). These data were used to determine whether these biomarkers could predict the tumor response. A univariate analysis showed that the patients who tested positive for HER2 expression (56.00% vs 11.67%, p<0.01), negative for Tau expression (41.94% vs 14.81%, p=0.005), negative for Bcl-2 expression (46.43% vs 14.04%, p<0.01) and had smaller (≤2 cm) tumors (45.00% vs 18.46%, p=0.02) were associated with higher pCR rates. A multivariate analysis showed that a HER2-positive status (OR: 6.244; 95%CI: 1.734-22.487; p=0.005), Bcl-2-negative status (OR: 0.236; 95%CI: 0.064-0.869; p=0.030) and smaller (≤2 cm) tumor sizes (OR: 0.188; 95%CI: 0.046-0.767; p=0.020) are independent predictors of pCRs. The tumor sizes were significantly reduced in patients with HER2-positive, Tau-negative, Bcl-2-negative and high Ki67 index breast cancer. In conclusion, Bcl-2 negative, HER2-positive and smaller (≤2 cm) tumor sizes are independent predictors of pCR in ER-positive patients treated with dose-dense (biweekly) paclitaxel/carboplatin NCT. This study is registered with ClinicalTrials.gov (NCT0205986).

7.
Sci Adv ; 3(3): e1601284, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28275729

RESUMO

The conservation of World Heritage is critical to the cultural and social sustainability of regions and nations. Risk monitoring and preventive diagnosis of threats to heritage sites in any given ecosystem are a complex and challenging task. Taking advantage of the performance of Earth Observation technologies, we measured the impacts of hitherto imperceptible and poorly understood factors of groundwater and temperature variations on the monuments in the Angkor World Heritage site (400 km2). We developed a two-scale synthetic aperture radar interferometry (InSAR) approach. We describe spatial-temporal displacements (at millimeter-level accuracy), as measured by high-resolution TerraSAR/TanDEM-X satellite images, to provide a new solution to resolve the current controversy surrounding the potential structural collapse of monuments in Angkor. Multidisciplinary analysis in conjunction with a deterioration kinetics model offers new insights into the causes that trigger the potential decline of Angkor monuments. Our results show that pumping groundwater for residential and touristic establishments did not threaten the sustainability of monuments during 2011 to 2013; however, seasonal variations of the groundwater table and the thermodynamics of stone materials are factors that could trigger and/or aggravate the deterioration of monuments. These factors amplify known impacts of chemical weathering and biological alteration of temple materials. The InSAR solution reported in this study could have implications for monitoring and sustainable conservation of monuments in World Heritage sites elsewhere.

8.
Bioresour Technol ; 146: 799-802, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23993285

RESUMO

Antimony (Sb(V)) in Sb mine drainage has adverse effects on the receiving water environments. This study for the first time demonstrated the feasibility of using sulfate-reducing bacteria (SRB) to convert sulfate ions in SMD into sulfides that reduce Sb(V) to Sb(III) and to form complex with Sb(III) as precipitate. The principal compound in the precipitate was stibnite (Sb2S3) at pH 7 and pH 9. The Sb(V) removal mechanism is sulfate-reduction and sulfide oxidization-precipitation, different from the conventional SRB-precipitation processes for heavy metals. The Sb(V)/sulfate ratio is noted an essential parameter affecting the Sb removal efficiency from SMD.


Assuntos
Antimônio/química , Mineração , Sulfatos/química , Sulfetos/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , China , Cristalografia por Raios X , Concentração de Íons de Hidrogênio , Íons , Cinética , Metais/química , Microscopia Eletrônica de Varredura , Oxigênio/química , Fatores de Tempo , Difração de Raios X
9.
Ecotoxicol Environ Saf ; 88: 163-8, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23228465

RESUMO

Chromium (Cr) is a toxic metal that poses a great threat to aquatic ecosystems. Information is limited on coinstantaneous responses of photosystems I (PSI) and II (PSII) to Cr(VI) stress due to lack of instruments that can simultaneously measure PSI and PSII activities. In the present study, responses of quantum yields of energy conversion and electron transport rates of PSI and PSII in Microcystis aeruginosa cells to Cr(VI) stress were simultaneously analyzed by a DUAL-PAM-100 system. Quantum yield of cyclic electron flow (CEF) under Cr(VI) stress and its physiological role in alleviating toxicity of Cr(VI) were also analyzed. At 5 mg L(-1) Cr(VI), quantum yield and electron transport rate of PSII decreased significantly, and light-induced non-photochemical fluorescence quenching lost. Cr(VI) also inhibited efficiency of PSII to use energy under high light more than of PSI. PSII showed lower maximal electron transport rate and light adaptability than PSI. Electron transport rate of PSI was higher and decreased less than that of PSII, implying less sensitivity of PSI to high light and Cr(VI). Energy dissipation through non-light-induced non-photochemical fluorescence quenching increased with increasing Cr(VI) concentration. CEF was stimulated under Cr(VI) treatment and made a significant contribution to quantum yield and electron transport of PSI, which was essential for protection of PSI from stresses of Cr(VI) and high light.


Assuntos
Cromo/toxicidade , Microcystis/efeitos dos fármacos , Complexo de Proteína do Fotossistema I/fisiologia , Complexo de Proteína do Fotossistema II/fisiologia , Poluentes Químicos da Água/toxicidade , Clorofila/metabolismo , Transporte de Elétrons/efeitos dos fármacos , Fluorescência , Luz , Microcystis/metabolismo
10.
IEEE Trans Biomed Eng ; 59(12): 3412-21, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22955867

RESUMO

A partially perturbed particle swarm optimization (PPSO) has been proposed for identifying the parameters of the Beeler-Reuter (BR) equation from action potential data. In the PPSO algorithm, the 63 BR equation parameters are divided into groups, and parameter patterns are made from the combination of the groups. PPSO enhances the capability of conventional particle swarm optimization (CPSO) by partially perturbing the coordinates of the globally best particle with the patterns when the searching process is locally confined. "Experimental data" were produced for cardiac myocytes simulated by the BR equation and the equation of Luo and Rudy (1991), and were used to test the algorithm of PPSO. The test results show that PPSO was able to identify the parameters of the BR equation effectively for different cardiac myocytes, while still retaining the conceptual simplicity and easy implementation of CPSO.


Assuntos
Potenciais de Ação/fisiologia , Algoritmos , Modelos Biológicos , Animais , Simulação por Computador , Potenciais da Membrana , Miócitos Cardíacos/fisiologia
11.
Sensors (Basel) ; 9(1): 503-18, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-22389613

RESUMO

The Interferometric Point Target Analysis (IPTA) technique and Advanced Synthetic Aperture Radar (ASAR) images acquired over Hong Kong from 2007-2008 were used to detect ground deformation in the urban area of Guangzhou city in South China. A ground deformation rate map with scattered distribution of point targets shows the maximum subsidence (rise) rate as high as -26 to -20 mma(-1) (16-21 mma(-1)), implying that the study area is an active zone for ground deformation. Based on the point target map, a contour ground deformation rate map is generated. The map shows three major subsidence zones located in the middle-west, the east, and the southwest of the study area, respectively. All the six ground collapse accidents that occurred in 2007-2008 fall within the subsidence zones, qualitatively validating the IPTA results. Ground subsidence and geological conditions on Datansha Island are examined. The results indicate that the local geological conditions, such as limestone Karst geomorphology as well as silt layers characterized by high water content, high void ratio, high compressibility, low bearing capacity and low shear strength, and underground engineering projects are responsible for ground subsidence and ground collapse accidents occurred there.

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