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141.
Garzoni M Cheval N Fahmi A Danani A Pavan GM 《Journal of the American Chemical Society》2012,134(7):3349-3357
The construction of hierarchical materials through controlled self-assembly of molecular building blocks (e.g., dendrimers) represents a unique opportunity to generate functional nanodevices in a convenient way. Transition-metal compounds are known to be able to interact with cationic dendrimers to generate diverse supramolecular structures, such as nanofibers, with interesting collective properties. In this work, molecular dynamics simulation (MD) demonstrates that acetate ions from dissociated Cd(CH(3)COO)(2) selectively generate cationic PPI-dendrimer functional fibers through hydrophobic modification of the dendrimer's surface. The hydrophobic aggregation of dendrimers is triggered by the asymmetric nature of the acetate anions (AcO(-)) rather than by the precise transition metal (Cd). The assembling directionality is also controlled by the concentration of AcO(-) ions in solution. Atomic force (AFM) and transmission electron microscopy (TEM) prove these results. This well-defined directional assembly of cationic dendrimers is absent for different cadmium derivatives (i.e., CdCl(2), CdSO(4)) with symmetric anions. Moreover, since the formation of these nanofibers is controlled exclusively by selected anions, fiber disassembly can be consequently triggered via simple ionic competition by NaCl salt. Ions are here reported as a simple and cost-effective tool to drive and control actively the assembly and the disassembly of such functional nanomaterials based on dendrimers. 相似文献
142.
Lim J Pavan GM Annunziata O Simanek EE 《Journal of the American Chemical Society》2012,134(4):1942-1945
The synthesis, characterization, and host-guest chemistry of high-generation triazine dendrimers are described. With pyrene and camptothecin as guests, experiments revealed that the guest capacity of odd-generation triazine dendrimers increased until generation 7 but decreased at generation 9. Molecular dynamics simulations conducted in explicit solvent showed a useful fingerprint for this behavior in radial distribution functions of water molecules penetrating the interior of the dendrimers. A linear relationship between the guest capacity of dendrimers measured experimentally and the number of water molecules within the interior determined computationally was observed. 相似文献
143.
Manisha Singla Pavan Mathur 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2009,74(2):536-543
A pentakis benzimidazole based penta-amide ligand diethylenetriamine—N,N,N′,N′,N″-pentakis(2-methyl benzimidazolyl)penta-amide [GBDTPA] has been synthesized and utilized to prepare Mn (II) complexes of general composition [Mn2(GBDTPA)X4], where X is an exogenous anionic ligand (X = Cl−, NO3− and Br−). The oxidation of alcohols has been investigated using [Mn2(GBDTPA)Cl4] as the catalyst and TBHP as an alternate source of oxygen. The respective aldehydic products have been isolated and characterized by 1H NMR. 相似文献
144.
C. Arnaboldi C. Brofferio A. Bryant C. Bucci L. Canonica S. Capelli M. Carrettoni M. Clemenza I. Dafinei S. Di Domizio F. Ferroni E. Fiorini Z. Ge A. Giachero L. Gironi A. Giuliani P. Gorla E. Guardincerri R. Kadel K. Kazkaz L. Kogler Y. Kolomensky J. Larsen M. Laubenstein Y. Li C. Maiano M. Martinez R. Maruyama S. Nisi C. Nones Eric B. Norman A. Nucciotti F. Orio L. Pattavina M. Pavan G. Pessina S. Pirro E. Previtali C. Rusconi Nicholas D. Scielzo M. Sisti Alan R. Smith W. Tian M. Vignati H. Wang Y. Zhu 《Journal of Crystal Growth》2010,312(20):2999-3008
High purity TeO2 crystals are produced to be used for the search for the neutrinoless double beta decay of 130Te. Dedicated production lines for raw material synthesis, crystal growth, and surface processing were built compliant with radio-purity constraints specific to rare event physics experiments. High sensitivity measurements of radio-isotope concentrations in raw materials, reactants, consumables, ancillaries, and intermediary products used for TeO2 crystals production are reported. Indications are given on the crystals perfection and how it is achieved and maintained in a large scale production process. Production and certification protocols are presented and resulting ready-to-use TeO2 crystals are described. 相似文献
145.
Synthesis of isofagomine has been achieved by implementation of aza-Claisen rearrangement of 2-C-hydroxymethyl glycals as a key step. The above rearrangement has also been utilized in the synthesis of biologically important polyhydroxylated piperidine frameworks such as isogalactofagomine, ent-isogalactofagomine and their analogues and some other azasugars as glycosidase inhibitors. 相似文献
146.
First measurement of the partial widths of 209Bi decay to the ground and to the first excited states
Beeman JW Biassoni M Brofferio C Bucci C Capelli S Cardani L Carrettoni M Clemenza M Cremonesi O Ferri E Giachero A Gironi L Gorla P Gotti C Nucciotti A Maiano C Pattavina L Pavan M Pessina G Pirro S Previtali E Sisti M Zanotti L 《Physical review letters》2012,108(6):062501
209Bi alpha decay to the ground and to the first excited state have been recently observed for the first time with a large BGO scintillating bolometer. The half-life of 209Bi is determined to be τ(1/2)=(2.01±0.08)×10(19) yr while the branching ratio for the ground-state to ground-state transition is (98.8±0.3)%. 相似文献
147.
Susan Moreno-Molek Salaam Saleh Druthiman Reddy Mantheni Manik Pavan Kumar Maheswaram Tobili Sam-Yellowe Alan T. Riga 《Journal of Thermal Analysis and Calorimetry》2012,108(1):79-85
Cytokines and soluble cytokine receptors serve as important protein biomarkers for chronic and infectious disease diagnosis.
The development of biosensors capable of detecting cytokines or their soluble receptors in patient bodily fluids is a growing
area of research. In an ongoing series of studies to understand the thermal analytical behavior of cytokines and their soluble
receptors, dielectric thermal analysis (DETA) and thermogravimetry (TG) were used in investigations to determine if differentiations
based on dielectric properties (e.g., conductivity) of the proteins could be identified. Permittivity (ε′) and dielectric
loss factor (ε″) measurements were performed over a frequency range of 0.1–300,000 Hz. Up to 20 min, water associated with
the samples was conductive, interacting with the proteins and affecting the temperature-dependent relaxation spectra of proteins.
A trend analysis revealed differences between surface charge at 0.1 Hz and bulk charge at 300,000 Hz. In addition, the greatest
change detected among proteins was due to the conductivity (dielectric loss factor). Beyond a 20 min drying time, the observed
conductivity was due to intrinsic properties of the proteins with limited dependence on frequency. A 100% water loss was obtained
for samples within 20–30 min by TG. Sample drying by TG could serve as a preparatory step in drying protein samples for further
DETA and DSC analysis. 相似文献
148.
We consider a solution of three dimensional New Massive Gravity with a negative cosmological constant and use the AdS/CTF correspondence to inquire about the equivalent two dimensional model at the boundary. We conclude that there should be a close relation of the theory with the Korteweg–de Vries equation. 相似文献
149.
150.
Gisele Luiza Pavan Igor Tadeu Lazzarotto Bresolin Mariana Borsoi-Ribeiro Mookambesvaran Vijayalakshmi Sonia Maria Alves Bueno 《Adsorption》2014,20(5-6):677-688
Over the past decade, immobilized metal-affinity adsorbents have attracted increasing interest for purification of natural and recombinant immunoglobulin G (IgG). In this work, nickel and cobalt metal ions complexed with CM-Asp (carboxymethylaspartate) immobilized on poly(ethylenevinyl alcohol) (PEVA) hollow fiber membranes were evaluated for purification of human IgG from serum. The buffer system and NaCl had important effects on human serum protein adsorption in both adsorbents. Efficient purification of IgG was accomplished in sodium phosphate buffer without NaCl at pH 7.0. Under this condition, the electrostatic interactions are important for adsorption. The Ni(II)-CM-Asp–PEVA had a protein adsorption capacity of 17.5 mg of IgG mL?1 fiber when human serum diluted was loaded in crossflow filtration mode and the eluted IgG had a purity of 82.6 % (based on total protein and IgG, IgM, HSA, and Trf nephelometric analysis). Fitting the experimental IgG adsorption data to the Langmuir and Langmuir–Freundlich models showed that Ni(II)-CM-Asp and Co(II)-CM-Asp had Langmuirean and non-Langmuirean behavior, respectively, with positive cooperativity for IgG-Co(II)-CM-Asp binding, probably due to multipoint interactions (n = 2.12 ± 0.31). Thus, these membranes can be considered as alternative adsorbents for the purification or depletion of IgG from human serum. 相似文献