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91.
Sharma S Soni VP Bellare JR 《Journal of materials science. Materials in medicine》2009,20(Z1):S93-100
Frequently metal implants undergo detachment from the host tissue due to inadequate biocompatibility and poor osteointegration. In view of this, bioactive porous apatite-wollastonite/chitosan nanocomposite coating was prepared using electrophoretic deposition (EPD) technique in the present work. The effect of coating duration and current density on surface characteristics of the nanocomposite coating was assessed using optical microscope and scanning electron microscope. EPD led to the formation of thick and homogeneous coating. Adhesion of the composite coating on titanium substrate was evaluated using tape test and bioactivity of the coatings was studied by immersing in simulated body fluid (SBF). The coating with higher current density and longer coating duration was found to be suitable with improved adhesion and bioactivity for intended metal implants. 相似文献
92.
Searchable Encryption Revisited: Consistency Properties, Relation to Anonymous IBE, and Extensions 总被引:2,自引:0,他引:2
Michel Abdalla Mihir Bellare Dario Catalano Eike Kiltz Tadayoshi Kohno Tanja Lange John Malone-Lee Gregory Neven Pascal Paillier Haixia Shi 《Journal of Cryptology》2008,21(3):350-391
We identify and fill some gaps with regard to consistency (the extent to which false positives are produced) for public-key
encryption with keyword search (PEKS). We define computational and statistical relaxations of the existing notion of perfect
consistency, show that the scheme of Boneh et al. (Advances in Cryptology—EUROCRYPT 2004, ed. by C. Cachin, J. Camenisch,
pp. 506–522, 2004) is computationally consistent, and provide a new scheme that is statistically consistent. We also provide a transform of
an anonymous identity-based encryption (IBE) scheme to a secure PEKS scheme that, unlike the previous one, guarantees consistency.
Finally, we suggest three extensions of the basic notions considered here, namely anonymous hierarchical identity-based encryption,
public-key encryption with temporary keyword search, and identity-based encryption with keyword search.
An extended abstract of this paper appears in Advances in Cryptology—CRYPTO 2005, ed. by V. Shoup, Santa Barbara, California, August 14–18, 2005, Lecture Notes in Computer Science, vol. 3621 (Springer,
Berlin, 2005), pp. 205–222. This is the full version. 相似文献
93.
An authenticated encryption scheme is a symmetric encryption scheme whose goal is to provide both privacy and integrity. We
consider two possible notions of authenticity for such schemes, namely integrity of plaintexts and integrity of ciphertexts,
and relate them, when coupled with IND-CPA (indistinguishability under chosen-plaintext attack), to the standard notions of
privacy IND-CCA and NM-CPA (indistinguishability under chosen-ciphertext attack and nonmalleability under chosen-plaintext
attack) by presenting implications and separations between all notions considered. We then analyze the security of authenticated
encryption schemes designed by “generic composition,” meaning making black-box use of a given symmetric encryption scheme
and a given MAC. Three composition methods are considered, namely Encrypt-and-MAC, MAC-then-encrypt, and Encrypt-then-MAC. For each of these and for each notion of security, we indicate whether or not the resulting scheme meets the notion in question
assuming that the given symmetric encryption scheme is secure against chosen-plaintext attack and the given MAC is unforgeable
under chosen-message attack. We provide proofs for the cases where the answer is “yes” and counter-examples for the cases
where the answer is “no.”
M. Bellare’s work was supported in part by a 1996 Packard Foundation Fellowship in Science and Engineering, NSF CAREER Award
CCR-9624439, NSF grants CNS-0524765 and CNS-0627779, and a gift from Intel Corporation.
C. Namprempre’s work was supported in part by grants of the first author and the Thailand Research Fund. 相似文献
94.
The effect of catalyst on the degradation of poly (ethylene terephthalate) (PET) waste by ammonolysis was investigated at
ambient temperature and atmospheric pressure. The products obtained by ammonolysis in the presence and absence of catalyst
were separated and characterized by spectroscopic techniques namely FTIR and Mass Spectrometry (MS) together with Scanning
Electron Microscopy (SEM) and Differential Thermal Analysis (DTA). The end products were characterized as 1, 4-benzene dicarboxamide
in both the cases and were found to be same throughout the course of reaction. The absence of peak for PET and appearance
of peak for 1, 4-benzene dicarboxamide in the FTIR spectra of end product along with MS, SEM and thermal analysis confirms
the completion of the reaction. The results show that the catalyst cut shorts the time of completion of reaction from 45 to
15 days only. 相似文献
95.
Marc A. Meyers Anuj Mishra David J. Benson 《JOM Journal of the Minerals, Metals and Materials Society》2006,58(4):41-48
This article presents a review of the principal mechanisms responsible for the plastic deformation of nanocrystalline metals.
As the concentration of grain boundaries increases, with a decrease in grain size there is a gradual shift in the relative
importance of the deformation mechanisms away from the ones operating in the conventional polycrystalline domain. This is
predicted by molecular dynamics simulations that indicate a preponderance of dislocation emission/annihilation at grain boundaries
and grain-boundary sliding when grain sizes are in the range 20–50 nm. Experiments show, in general, a saturation in work
hardening at low strains, which is indicative of a steady-state dislocation density. This saturation is accompanied by an
increased tendency toward shear localization, which is supportive of dislocation generation and annihilation at grain boundaries.
Dislocation analyses recently proposed corroborate the computational predictions and provide a rational foundation for understanding
the mechanical response. 相似文献
96.
Prem Chand Ramesh C. Srivastava Anuj Upadhyay 《Journal of Alloys and Compounds》2008,460(1-2):108-114
The Ni1+xTixFe2−2xO4 (0 ≤ x ≤ 0.1) ferrite systems prepared by a semi-chemical route, have been studied by electron paramagnetic resonance (EPR) at X-band, Mössbauer spectroscopy and magnetization measurements at various temperatures. EPR spectra of these samples comprise generally a broad and asymmetric EPR signal. The variation of geff and peak-to-peak line width ΔHpp, with Ti concentration and temperature are attributed to the variation of dipole–dipole interaction and the superexchange interaction. Mössbauer spectra comprise two sets of sextet attributed to Fe3+ at two distinct sites-A and -B. Ti4+ ions are concluded to occupy the octahedral B-sites. Magnetic moment is found to decrease with the increase of Ti4+ concentration. The effective magnetic field Heff at the A-sites also follows a similar trend. The reason is attributed to the canted structure of spins in the Ti-doped samples. An anomalous behavior at x = 0.015 is observed in the properties studied here and some sort of phase change is believed to occur at 473 K in these ferrites. 相似文献
97.
98.
In cryptographic protocols it is often necessary to verify/certify the tools in use. This work demonstrates certain subtleties in treating a family of trapdoor permutations in this context, noting the necessity to check certain properties of these functions. The particular case we illustrate is that of noninteractive zero-knowledge. We point out that the elegant recent protocol of Feige, Lapidot, and Shamir for proving NP statements in noninteractive zero-knowledge requires an additional certification of the underlying trapdoor permutation, and suggest a method for certifying permutations which fills this gap.A preliminary version of this paper appeared in Advances in Cryptology—Crypto 92 Proceedings, Lecture Notes in Computer Science, Vol. 740, E. Brickell, ed., Springer-Verlag, Berlin, 1992. This work was done while Mihir Bellare was at the IBM T.J. Watson Research Center, Yorktown Heights, NY. 相似文献
99.
Kurtek S Klassen E Gore JC Ding Z Srivastava A 《IEEE transactions on pattern analysis and machine intelligence》2012,34(9):1717-1730
This paper presents a novel Riemannian framework for shape analysis of parameterized surfaces. In particular, it provides efficient algorithms for computing geodesic paths which, in turn, are important for comparing, matching, and deforming surfaces. The novelty of this framework is that geodesics are invariant to the parameterizations of surfaces and other shape-preserving transformations of surfaces. The basic idea is to formulate a space of embedded surfaces (surfaces seen as embeddings of a unit sphere in IR3) and impose a Riemannian metric on it in such a way that the reparameterization group acts on this space by isometries. Under this framework, we solve two optimization problems. One, given any two surfaces at arbitrary rotations and parameterizations, we use a path-straightening approach to find a geodesic path between them under the chosen metric. Second, by modifying a technique presented in [25], we solve for the optimal rotation and parameterization (registration) between surfaces. Their combined solution provides an efficient mechanism for computing geodesic paths in shape spaces of parameterized surfaces. We illustrate these ideas using examples from shape analysis of anatomical structures and other general surfaces. 相似文献
100.
Management of coronary artery disease and acute coronary syndrome in the chronic kidney disease population—A review of the current literature 下载免费PDF全文
Justin M. Lingel Mukta C. Srivastava Anuj Gupta 《Hemodialysis international. International Symposium on Home Hemodialysis》2017,21(4):472-482
Coronary Artery Disease (CAD) is a large contributor to morbidity and mortality in the chronic kidney disease (CKD) and end‐stage renal disease (ESRD) population. Due to the fact that many large‐scale trials evaluating management for acute coronary syndromes (ACS) and CAD have excluded patients with CKD, there is a paucity of data investigating medical management of CAD and revascularization strategies of these patients. Further, while there have been many advances in the treatment for ACS and CAD, both medically and technologically, few studies have focused on the CKD population and many predate these advancements in management. Newer studies that include CKD patients have shown heterogeneity in various outcomes, making management decisions challenging. In this review, we summarize the epidemiologic significance of ACS and CAD in patients with CKD, discuss the diagnosis of ACS in this patient population, and review the therapeutic interventions in patients with CKD. 相似文献