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41.
1s binding energies are calculated for nitrogen atoms in thymine, pyrrole, adenine, and pyridine and for carbon atoms in thymine, adenine, pyrrole, and furan, and compared with experimental values. Calculations are performed in the framework of a perturbational model using CNDO molecular wave functions. Interactions of the 1s electron with its own atom are calculated exactly whereas interactions with neighbor atoms are calculated according to two levels of approximation: (1) Point charge approximation. (2) Rigorous calculations of integrals. Magnitudes of the different interactions and integrals are analysed. The questions of assignments of ESCA shifts and the errors inherent in the calculations are discussed.  相似文献   
42.
A conforming, two-node conical element is presented incorporating both transverse shear deformation and rotary inertia effects. The success of the formulation is based on the C0 continuity shape functions that, in addition to providing full kinematic compatibility, satisfy the interdependent variable interpolation requirement. This requirement points toward a particular dependence of the kinematic variable interpolations which allow for the satisfaction of the Kirchhoff constraint everywhere in the element domain. There exists an internal degree-of-freedom reduction achieved by means of a continuous shear constraint condition. In the derivation of element matrices, Hamilton's principle is invoked with Gaussian quadratures ensuring exact integration throughout. Excellent convergence characteristics and high accuracy results attainable with the element are demonstrated in static and free vibration problems for thin and moderately thick plates and shells.  相似文献   
43.
Immobilized TiO2 nanotube electrodes with high surface areas were grown via electrochemical anodization in aqueous solution containing fluoride ions for photocatalysis applications. The photoelectrochemical properties of the grown immobilized TiO2 film were studied by potentiodynamic measurements (linear sweep voltammetry), in addition to the calculation of the photocurrent response. The nanotube electrode properties were compared to mesoporous TiO2 electrodes grown by anodization in sulfuric acid at high potentials (above the microsparking potential) and to 1 g/l P-25 TiO2 powder. Photocatalyst films were evaluated by high resolution SEM and XRD for surface and crystallographic characterization. Finally, photoelectrocatalytic application of TiO2 was studied via inactivation of E. coli. The use of the high surface area TiO2 nanotubes resulted in a high photocurrent and an extremely rapid E. coli inactivation rate of ∼106 CFU/ml bacteria within 10 min. The immobilized nanotube system is proven to be the most potent electrode for water purification.  相似文献   
44.
In this paper,Lp-ofdm is combined with differentMimo schemes in order to improve performance in terms of diversity gain and to exploit capacity brought by theMimo channel. The original contribution is the development of a generic iterative receiver designed forLp mimo transmission able to work whatever the antenna configuration and the spatial coding scheme. By using a globalMmse criterion, interference terms coming from space-time coding and linear precoding are jointly treated leading to a very good trade-off between performance and complexity compared to trellis based detectors particularly for high order modulations, high number of antennas and/or large size of precoding matrices.  相似文献   
45.
46.
Modern therapy of acute myeloid leukemia (AML) began in 1973 with the first report of the successful combination of daunorubicin and cytarabine, which led to complete remission in approximately 45% of patients. Accurate AML diagnosis was dependent on morphology, aided initially only by cytochemistry. Unlike acute lymphoblastic leukemia (ALL), immunophenotyping offered little in the diagnosis of AML, at least during the 1970s and 1980s. The advent of reliable cytogenetics changed the entire prognostic outlook of AML. With karyotypic analysis, different groups of AML could be classified and stratified for various therapies. Unique mutational profiling was a major advance in further categorizing AML patients, aided by the immunophenotypic identification of antigenic markers on the cells. All these advances were occurring as the understanding of the importance of the tumor burden—known as minimal residual disease (MRD)—became crucial for the management of AML patients. The efficacy of MRD has rapidly progressed in the past decade, from a specificity of 10−3 with immunophenotyping to 10−4 with polymerase chain reaction (PCR), which is only appropriate for some patients with AML, and finally to 10−5 or even 10−6 cells with the extraordinary sensitivity of next-generation sequencing (NGS). All of these advances have promoted the concept of personalized medicine, which has led to the advent of targeted agents that can accurately be used for specific diagnostic subtypes. Responses can be predicted and measured accurately. Such targeted agents have now become a cornerstone in the management of AML, increasing efficacy and dramatically reducing toxicity. The focus of this review is on one of the most well-studied targeted agents in AML: the FMS-like tyrosine kinase 3 (FLT3) inhibitors, which have impacted the prognostication and therapeutics of AML. This review selectively discusses the FLT3 inhibitors in detail, as a model for the other burgeoning targeted agents that have already been approved, as well as those that are currently in development.  相似文献   
47.
Biaxially oriented linear low density polyethylene (LLDPE) films were produced using the double bubble process with different machine direction (MD) orientation levels and the same transverse direction (TD) blow‐up ratio. Their mechanical behavior was characterized in terms of the tensile strength and tear resistance. The viscoelastic behavior of oriented films was studied using dynamic‐mechanical thermal analysis (DMTA). The microstructure and orientation were characterized using microscopy, X‐ray diffraction pole figures, and birefringence. The results indicate that MD ultimate tensile strength increases and the TD one decreases with MD stretching ratio. Tear propagation resistance, in general, remained mainly constant in TD and decreased in MD, as the draw ratio was increased. The morphology analyses exhibit a typical biaxial lamellar structure for all samples with different lamellar dimensions. Orientation of c‐axis in crystalline phase, molecular chain in amorphous phase along MD increased with draw ratio. In most crystals, a‐axis was located in the normal direction (ND) and the b‐axis in the ND–TD plane. A good correlation was observed between c‐axis orientation factor and MD mechanical properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3545–3553, 2006  相似文献   
48.
Effect of oxidants on microalgal flocculation   总被引:5,自引:0,他引:5  
The effects of chlorine, ozone and chlorine dioxide on Scenedesmus sp. cultures were studied. Algal cell viability and chlorophyll concentration decreased, and the concentration of dissolved organic substances increased with increasing applied oxidant concentration. Pretreatment with chlorine dioxide (1, 3 or 5 mg l−1) or ozone (2.6, 4.6 or 8.1 mg l−1) on algal cultures enhanced algal flocculation with alum, while prechlorination with 10 or 20 mg l−1 increased the required dosage of alum by 15%. Scanning electron micrographs of oxidized cells revealed drastically adverse effects upon the cell surface architecture: in addition to the oxidation of noncellular organic materials, the oxidants damaged both cell surface structures and intracellular components. A model explaining the effects of the different oxidants on microalgal flocculation is suggested.  相似文献   
49.
Fatty acids (FA) are well known as efficient enhancers for transdermal delivery of drugs; however, their frequent dermal toxicity limits their regular use. In order to utilize the fatty acid as a safe enhancer devoid of its irritant effect, we have synthesized and evaluated a series of fatty acids conjugated to propylene glycol (FA-PG). Each one of the conjugates was prepared as a mono- or di- acyl ester derivative. The effects of the synthetic enhancers on the porcine skin permeability were evaluated in a diffusion cell system using lidocaine as the model drug. In addition, in vivo examinations in rabbits were preformed for skin toxicological evaluation. The results indicate that among the FA-PG conjugates, oleic acid (C18:1(n-9))-PG, linoleic acid (C18:2(n-6))-PG and alpha-linolenic acid (C18:3(n-3))-PG, mono- or di-esters, enhance the penetration of lidocaine relatively to the vehicle (without enhancer). The conjugates of oleic acid (C18:1(n-9)) and linoleic acid (C18:2(n-6)) with PG have demonstrated a similar enhancing effect as the corresponding free fatty acids. Interestingly, although the mono- or the di- conjugates of alpha-linolenic acid (C18:3(n-3)) with PG enhanced the lidocaine flux as the other two fatty acid conjugates, they resulted in a reduced permeability as compared to the action of their free acid. In addition, the mono-conjugates of alpha-linolenic acid (C18:3(n-3)) with PG exhibited elevated skin irritation in rabbits (relative to the fatty acid alone) compared to the significantly reduced irritation of oleate-PG and linoeate-PG mono-conjugates. In conclusion, except saturated FA-PG and alpha-linolenic acid (C18:3(n-3)) - PG mono-conjugates, unsaturated fatty acids (e.g., oleic and linoleic acids) after conjugation to PG may be safe and effective enhancers for delivering topical drugs.  相似文献   
50.
AJ Ben-Sasson  N Tessler 《Nano letters》2012,12(9):4729-4733
While organic transistors' performances are continually pushed to achieve lower power consumption, higher working frequencies, and higher current densities, a new type of organic transistors characterized by a vertical architecture offers a radically different design approach to outperform its traditional counterparts. Naturally, the distinct vertical architecture gives way to different governing physical ground rules and structural key features such as the need for an embedded transparent electrode. In this paper, we make use of a zero-frequency electric field-transparent patterned electrode produced through block-copolymer self-assembly based lithography to control the performances of the vertical organic field effect transistor (VOFET) and to study its governing physical mechanisms. Unlike other VOFET structures, this design, involving well-defined electrode architecture, is fully tractable, allowing for detailed modeling, analysis, and optimization. We provide for the first time a complete account of the physics underpinning the VOFET operation, considering two complementary mechanisms: the virtual contact formation (Schottky barrier lowering) and the induced potential barrier (solid-state triode-like shielding). We demonstrate how each mechanism, separately, accounts for the link between controllable nanoscale structural modifications in the patterned electrode and the VOFET performances. For example, the ON/OFF current ratio increases by up to 2 orders of magnitude when the perforations aspect ratio (height/width) decreases from ~0.2 to ~0.1. The patterned electrode is demonstrated to be not only penetrable to zero-frequency electric fields but also transparent in the visible spectrum, featuring uniformity, spike-free structure, material diversity, amenability with flexible surfaces, low sheet resistance (20-2000 Ω sq(-1)) and high transparency (60-90%). The excellent layer transparency of the patterned electrode and the VOFET's exceptional electrical performances make them both promising elements for future transparent and/or efficient organic electronics.  相似文献   
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