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排序方式: 共有145条查询结果,搜索用时 15 毫秒
21.
Cretu N. Nita G. Boer A. 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2008,55(2):415-420
We performed experimental and computational studies of the acoustic transfer power coefficient for carbon steel cylindric bars placed in axial magnetic field. By experiment, the transmission coefficients of velocity were measured for ferromagnetic bars during the first magnetization curve below saturation. Using the magnetic and magnetostriction material measurements we obtained the profile of the magnetostriction along the distance for a ferromagnetic cylindrical rod placed in a magnetic field parallel with its axis. The data were compared with numerical results obtained by computer simulation, under the assumption of spatial dependent acoustic impedance and phase velocity, leading to the conclusion that the Young modulus is affected by the magnetoelastic interaction according to a linear decrease. 相似文献
22.
Oana Baldasici Loredana Balacescu Daniel Cruceriu Andrei Roman Carmen Lisencu Bogdan Fetica Simona Visan Andrei Cismaru Ancuta Jurj Lucian Barbu-Tudoran Valentina Pileczki Laurian Vlase Oana Tudoran Ovidiu Balacescu 《International journal of molecular sciences》2022,23(20)
Neo-adjuvant therapy (NAT) is increasingly used in the clinic for the treatment of breast cancer (BC). Pathological response to NAT has been associated with improved patients’ survival; however, the current techniques employed for assessing the tumor response have significant limitations. Small EVs (sEVs)-encapsulated miRNAs have emerged as promising new biomarkers for diagnosis and prediction. Therefore, our study aims to explore the predictive value of these miRNAs for the pathological response to NAT in BC. By employing bioinformatic tools, we selected a set of miRNAs and evaluated their expression in plasma sEVs and BC biopsies. Twelve miRNAs were identified in sEVs, of which, miR-21-5p, 221-3p, 146a-5p and 26a-5p were significantly associated with the Miller–Payne (MP) pathological response to NAT. Moreover, miR-21-5p, 146a-5p, 26a-5p and miR-24-3p were independent as predictors of MP response to NAT. However, the expression of these miRNAs showed no correlation between sEVs and tissue samples, indicating that the mechanisms of miRNA sorting into sEVs still needs to be elucidated. Functional analysis of miRNA target genes and drug interactions revealed that candidate miRNAs and their targets, can be regulated by different NAT regimens. This evidence supports their role in governing the patients’ therapy response and highlights their potential use as prediction biomarkers. 相似文献
23.
Strachan NJ Doyle MP Kasuga F Rotariu O Ogden ID 《International journal of food microbiology》2005,103(1):35-47
A human dose response model for Escherichia coli O157 would enable prediction of risk of infection to humans following exposure from either foodborne or environmental pathways. However, due to the severe nature of the disease, volunteer human dose response studies cannot be carried out. Surrogate models from Shigella fed to humans and E. coli O157 to rabbits have been utilised but are significantly different to one another. In addition data obtained by animal exposure may not be representative for human beings. An alternative approach to generating and validating a dose response model is to use quantitative data obtained from actual human outbreaks. This work collates outbreak data obtained from global sources and these are fitted using exponential and beta-Poisson models. The best fitting model was found to be the beta-Poisson model using a beta-binomial likelihood and the authors favour the exact version of this model. The confidence levels in this model encompass a previously published Shigella dose response model. The potential incorporation of this model into QMRAs is discussed together with applications of the model to help explain foodborne outbreaks. 相似文献
24.
Ioana Lacatusu Elena Mitrea Nicoleta Badea Raluca Stan Ovidiu Oprea Aurelia Meghea 《Journal of Functional Foods》2013,5(3):1260-1269
This study aimed at exploring the behavior of fish oil enriched with ω-3 fatty acids in order to obtain stable lipid nanocarriers (NLCs) with improved characteristics as effective delivery systems for lutein. The particle size of optimized lutein-NLCs was below 200 nm. The less ordered arrangement of lipid core revealed by scanning calorimetry and the high entrapment efficiency of 88.5% clearly indicated the appropriate role of fish oil in obtaining effective lipid nanocarriers. The evaluation of in vitro antioxidant activity has demonstrated a significant blocking effect of NLCs, scavenging up to 98% oxygen free radicals. The in vitro release profile has shown that NLCs are able to ensure a better, in vitro sustained release of lutein as compared to conventional nanoemulsions. 相似文献
25.
Dan Lupu Ovidiu ArdeleanGabriela Blanita Gheorghe BorodiMihaela D. Lazar Alexandru R. BirisColdea Ioan Maria MihetIoan Misan Gabriel Popeneciu 《International Journal of Hydrogen Energy》2011,36(5):3586-3592
A new metal-organic framework [Fe3O(OOC-C6H4-COO)3(H2O)3]Cl·(H2O)x was synthesized with a specific surface area of 2823 m2/g and a lattice parameter of 88.61 Å. Isostructural with MIL-101, this compound exhibits similar hydrogen adsorption properties, with maximum adsorption capacity of 5.1wt.% H at 77 K. The adsorption enthalpy of hydrogen for MIL-101 and ITIM-1 (MIL-101Fe) at zero coverage was calculated for a wide temperature range of 77 K ÷ 324 K, considering corrections for the variation of hydrogen gas entropy with the temperature. The resulted adsorption enthalpy is 9.4 kJ/mol for MIL-101, in excellent agreement with the value reported in literature from microcalorimetric measurements, and a value of 10.4 kJ/mol at zero coverage was obtained for ITIM-1 (MIL-101Fe). 相似文献
26.
Raluca C. Cretu Delia M. Gligor Laura Muresan Ionel Catalin Popescu Liana M. Muresan 《Journal of Applied Electrochemistry》2006,36(12):1327-1332
Prussian Blue-modified graphite electrodes (G/PB) with electrocatalytic activity toward H2O2 reduction were obtained by PB potentiostatic electrodeposition from a mixture containing 2.5 mm FeCl3 + 2.5 mm K3[Fe(CN)6] + 0.1 m KCl + 0.1 m HCl. From cyclic voltammetric measurements, performed in KCl aqueous solutions of different concentrations (5 × 10−2–1 m), the rate constant for the heterogeneous electron transfer (k
s) was estimated by using the Laviron treatment. The highest ks value (10.7 s−1) was found for 1 m KCl solution. The differences between the electrochemical parameters of the voltammetric response, as well as the shift of the formal potential, observed in the presence of Cl− and NO3− compared to those observed in the presence of SO42− ions, points to the involvement of anions in the redox reactions of PB. The G/PB electrodes showed a good electrochemical stability proved by a low deactivation rate constant (0.8 × 10−12 mol cm2 s−1). The electrocatalytic efficiency, estimated as the ratio
, was found to be 3.6 (at an applied potential of 0 mV vs. SCE; Γ = 5 × 10−8 mol cm−2) for a H2O2 concentration of 5 mm, thus indicating G/PB electrodes as possible H2O2 sensors. 相似文献
27.
Laser wakefield accelerators (LWFAs) are considered to be one of the most competitive next-generation accelerator candidates.In this paper,we will study the potential high-flux electron beam production of an LWFA driven by petawatt-level laser pulses.In our three-dimensional particle-in-cell simulations,an optimal set of parameters gives ~40 nC of charge with 2 PW laser power,thus ~400 kA of instantaneous current if we assume the electron beam duration is 100 fs.This high flux and its secondary radiation are widely applicable in nuclear and QED physics,industrial imaging,medical and biological studies. 相似文献
28.
Toshihiko Yamaguchi Ovidiu Mihalache 《Journal of Nuclear Science and Technology》2017,54(11):1201-1214
A new design has been adopted for the steam generator (SG) tubes of the Japan Sodium-cooled Fast Reactor (JSFR) using double-wall tubes. This paper estimates and assesses the effectiveness of detecting defects in SG double-wall tubes of the JSFR by using combined high-frequency eddy current testing (ECT) and low-frequency remote field eddy current sensors. We confirm that the proposed hybrid ECT sensor is highly sensitive to small defects, fatigue cracks, and other defects even when located under support plates of tubes. The parameters of the hybrid ECT sensor are designed and optimized to detect small defects using accurate numerical simulations based on the finite element method, using an in-house developed code. The sensitivity and high performance of the hybrid ECT sensor was validated with experimental measurements. 相似文献
29.
Krapal AM Popa OP Iorgu EI Costache M Popa LO 《International journal of molecular sciences》2012,13(2):2515-2520
The invasive softshell clam (Mya arenaria Linnaeus, 1758) is native to the northwestern region of the Atlantic Ocean. This species has been introduced in the northeast Pacific and along the European coasts, due to intense naval transports and aquaculture, and it is now present in all the European seas. In this paper we describe seven new microsatellite loci for Mya arenaria. The isolated loci are polymorphic with a number of alleles per locus between 6 and 14. The observed and expected heterozygosities ranged from 0.417 to 0.951, and from 0.643 to 0.895, with an average of 0.716 and 0.775, respectively. These microsatellite markers should be useful in analyzing this species' genetic diversity, which could explain various processes of its invasion history. 相似文献
30.
Elie H. Sarraf Ankit Kansal Mrigank Sharma Edmond Cretu 《Journal of Electronic Testing》2012,28(5):599-614
We propose a novel adaptive technique based on pseudo-random (PN) sequences for self-calibration and self-testing of MEMS-based inertial sensors (accelerometers and gyroscopes). The method relies on using a parameterized behavioral model implemented on FPGA, whose parameters values are adaptively tuned, based on the response to test pseudo-random actuation of the physical structure. Dedicated comb drives actuate the movable mass with binary maximum length pseudo-random sequences of small amplitude, to keep the device within the linear operating regime. The frequency of the stimulus is chosen within the mechanical spectral operating range of the micro-device, such that the induced response leads to the identification of the mechanical transfer function, and to the tuning of the associated digital behavioral model. In case of a micro-gyroscope, experimental results demonstrate the adaptive tracking of the damping coefficient from 5.57?×?10?5? Kg/s to 7.12?×?10?5? Kg/s and of the stiffness coefficient from 132?N/m to 137.7?N/m. In the case of a MEMS accelerometer, the damping and stiffness coefficients are correctly tracked from 3.4?×?10?3? Kg/s and 49.56?N/m to 4.57?×?10?3? Kg/s and 51.48?N/m, respectively—the former values are designer-specified target values, while the latter are experimentally measured parameters for fabricated devices operating in a real environment. Hardware resources estimation confirms the small area the proposed algorithm occupies on the targeted FPGA device. 相似文献