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51.
Thirty-eight second allogeneic bone marrow transplants (BMT) for acute leukemia relapsed after first BMT were performed in 13 Italian centers between 1987 and 1994. Twenty-one patients had acute myelogenous leukemia (AML), 17 acute lymphoblastic leukemia (ALL); at second BMT 24 patients were in complete remission (CR) and 14 in relapse. The median time to relapse after first BMT was 10 months (range 1-70). Grade II or greater acute graft-versus-host disease (GVHD) after second transplant occurred in 34.2% of patients and a chronic GVHD in 31.5% of patients. Twenty-four patients died: seven from early transplant-related mortality (TRM), 13 from relapse and four from late toxicity. As of 31 July 1996, at a median follow-up of 47 months (range 22-85), there are 14 survivors. The three-year probability of TRM, relapse and event-free survival (EFS) is 28%, 40% and 42% respectively. In 20 of 27 evaluable patients, remission duration after second BMT was longer than after the first BMT. A diagnosis of AML was correlated with a better outcome. These data support the usefulness of second allograft in selected patients with AML relapsing after a first BMT.  相似文献   
52.
Friedel-Crafts acylations with modified clays as catalysts   总被引:1,自引:0,他引:1  
Friedel-Crafts acylations are very effectively catalyzed by clays modified through exchange of the interlamellar cations or through impregnation of metal chlorides. The acidic K10 montmorillonite exchanged with iron(III) gives outstanding results in quantitative (98–100%) acylation of anisole (15 min), mesitylene (15 min), and p-xylene (3 h) at 140–160 °C. Clays impregnated with zinc chloride, such as the K10 montmorillonite, or Japanese acidic clay show near-equivalent catalytic performance.  相似文献   
53.
Computational methods for the estimation of stoichiometric association constants for multiple-ligand binding systems are currently based on non-linear least-squares regression analysis. These computational methods require sophisticated, iterative algorithms to assure convergence to a solution, as well as initial parameter and error estimates. A simple procedure, called lambda-invariance testing (LIT), was developed that provides a single-pass (non-iterative) estimation of stoichiometric association constants. The LIT method was applied to simulated binding data containing Gaussian error and to real data drawn from the literature. This method provided parameter estimates essentially equivalent to those obtained by least-squares regression analysis, with no initial parameter or error estimates required.  相似文献   
54.
This paper discusses a number of special ultrasonic NDE problems of particular interest to inertia and friction welds, but most of the results can be readily applied to other similar or dissimilar solid-state bonds as well. One of the major problems associated with dissimilar bonds is the blinding effect of the strong interface reflection caused by the inherent elastic discontinuity at the otherwise flawless boundary. A novel signal-processing technique based on the symmetric part of the boundary reflections from the two opposite sides of the interface is introduced and shown to yield a quantitative measure of boundary imperfection even for very good, apparently flawless bonds. The second problem addressed in this paper is the so-called cold-weld effect. As a combined result of heat softening and external pressure, intimate mechanical contact can be achieved without real fusion. Frequency analysis of the reflected ultrasonic signal from such cold-welded areas is shown to be capable of measuring the degree of plastic deformation at the contacting surfaces and, indirectly, to assess interface pressure and temperature. The third problem considered in this paper is the ultrasonic evaluation of the characteristic layered distribution of the grain structure in flawless inertia and friction welds. As an example, the thickness of the heat-affected zone (HAZ) was determined by ultrasonic spectroscopy, and the results were found to be in good agreement with independent optical profile measurements. Furthermore, the HAZ thickness is shown to be strongly correlated to welding pressure, therefore it offers a sensitive indicator for bond quality assessment as well.  相似文献   
55.
We prove the secret key rate formulas and derive security threshold parameters of multicarrier continuous‐variable quantum key distribution CVQKD. In a multicarrier CVQKD scenario, the Gaussian input quantum states of the legal parties are granulated into Gaussian subcarrier continuous variables (CVs). The multicarrier communication formulates Gaussian subchannels from the physical quantum channel, each dedicated to the transmission of a subcarrier CV. The Gaussian subcarriers are decoded by a unitary CV operation, which results in the recovered single‐carrier Gaussian CVs. We derive the formulas through the adaptive multicarrier quadrature division (AMQD) scheme, the singular value decomposition (SVD)–assisted AMQD, and the multiuser AMQD multiuser quadrature allocation (MQA). We prove that the multicarrier CVQKD leads to improved secret key rates and higher tolerable excess noise in comparison with single‐carrier CVQKD. We derive the private classical capacity of a Gaussian subchannel and the security parameters of an optimal Gaussian collective attack in the multicarrier setting. We reveal the secret key rate formulas for one‐way and two‐way multicarrier CVQKD protocols, assuming homodyne and heterodyne measurements and direct and reverse reconciliation. The results reveal the physical boundaries of physically allowed Gaussian attacks in a multicarrier CVQKD scenario and confirm that the improved transmission rates lead to enhanced secret key rates and security thresholds.  相似文献   
56.
An integrated library information system is a resource planning system for a library, used to track resources owned, bills paid, orders made, and patrons who have borrowed. In our research, we focused on university library information systems (ULISs). We identified an important research question regarding their main limitation in offering intelligent help to the students in their documentation/learning. We identified the importance of the endowment of ULISs with artificial intelligence. In this article, we analyzed different aspects related to the presence of computational intelligence in ULISs and intelligence of ULISs. Finally, we proposed a complex next generation ULIS based on a hybrid cooperative learning, being able to offer an intelligent help for personalized learning of students. We defined some novel paradigms in the context of a novel kind of cooperative hybrid personalized learning, such as learning role and sub-role; and learning intelligence level.  相似文献   
57.
Hybrid materials displaying multistage security behavior, where a single material shows both wavelength‐ and temperature‐dependent luminescence properties, are reported. The materials consist of mixed‐lanthanide β‐diketonate complexes grafted into the pores of a nanosized 2,2′‐bipyridine‐5,5′‐dicarboxylate‐acid MOF. A very specific choice of lanthanides and their ratios, as well as β‐diketonate ligand, is crucial for obtaining the desired properties. The wavelength‐dependent luminescence properties of the materials are very well matched with the excitation wavelengths of a standard UV lamp, and a clearly visible change in luminescence is observed in a narrow temperature range (slightly below and above room temperature), proving them to be excellent materials for use in anti‐counterfeit technologies, which would be almost impossible to mimic.  相似文献   
58.
Novel functional groups can be introduced into vegetable oils using enzymes, resulting in value-added products. The transesterification kinetics of ethyl ferulate with MAG, DAG, and TAG were examined. Transesterification was catalyzed by immobilized Candida antarctica lipase B in solventless batch and packed-bed reactors. Initial reaction rates with TAG were slightly sensitive to water activity, whereas rates with MAG and DAG were water activity independent. Transesterification was also three-to sixfold faster with MAG and DAG. These observations indicate that the reaction is rate limited by the acyl acceptor, and that oils with free hydroxyl groups are preferred acyl acceptors in comparison with TAG, which must undergo partial hydrolysis before becoming reactive.  相似文献   
59.
Chiral intermediates were prepared by biocatalytic processes with oxidoreductases for the chemical synthesis of some pharmaceutical drug candidates. These include: (i) the microbial reduction of 1-(4-fluorophenyl)-4-[4-(5-fluoro-2-pyrimidinyl)-1-piperazinyl]-1-butanone (1) to R-(+)-1-(4-fluorophenyl)-4-[4-(5-fluoro-2-pyrimidinyl)-1-piperazinyl]-1-butanol (2) [R-(+)-BMY 14802], an antipsychotic agent; (ii) the reduction of N-4-(1-oxo-2-chloroacetyl ethyl) phenyl methane sulfonamide (3) to the corresponding chiral alcohol (4), an intermediate for d-(+)-N-4-{1-hydroxy-2-[(-methylethyl)amino]ethyl}phenyl methanesulfonamide [d-(+) sotalol], a β-blocker with class III antiarrhythmic properties; (iii) biotransformation of Nɛ-carbobenzoxy (CBZ)-l-lysine (7) to Nɛ-CBZ-l-oxylysine (5), an intermediate needed for synthesis of (S)-1-[6-amino-2-{[hydroxy(4-phenylbutyl)phosphinyl]oxy}1-oxohexyl]-l-proline (ceronapril), a new angiotensin converting enzyme inhibitor (6) and (iv) enzymatic synthesis of l-β-hydroxyvaline (9) from α-keto-β-hydroxyisovalerate (16). l-β-Hydroxyvaline (9) is a key chiral intermediate needed for the synthesis of S-(Z)-{[1-(2-amino-4-thiazolyl)-2-{[2,2-dimethyl-4-oxo-1-(sulfooxy)-3-azetidinyl] amino}-2-oxoethylidene]amino}oxyacetic acid (tigemonam) (10), an orally active monobactam.  相似文献   
60.
Laszlo HE  Griffin MJ 《Ergonomics》2011,54(5):488-496
The extent to which a glove modifies the risks from hand-transmitted vibration is quantified in ISO 10819:1996 by a measure of glove transmissibility determined with one vibration magnitude, one contact force with a handle and only three subjects. This study was designed to investigate systematically the vibration transmissibility of four 'anti-vibration' gloves over the frequency range 16-1600 Hz with 12 subjects, at six magnitudes of vibration (0.25-8.0 ms(-2) r.m.s.) and with six push forces (5 N to 80 N). The four gloves showed different transmissibility characteristics that were not greatly affected by vibration magnitude but highly dependent on push force. In all conditions, the variability in transmissibility between subjects was as great as the variability between gloves. It is concluded that a standardised test of glove dynamic performance should include a wide range of hands and a range of forces representative of those occurring in work with vibratory tools. STATEMENT OF RELEVANCE: The transmission of vibration through anti-vibration gloves is highly dependent on the push force between the hand and a handle and also highly dependent on the hand that is inside the glove. The influence of neither factor is well reflected in ISO 10819:1996, the current standard for anti-vibration gloves.  相似文献   
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