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991.
The dynamics of a population, with its growth characterised by two stages namely an initial non-reproductive stage of length ρ, resistant to the environmental fluctuations and a second susceptible stage adding continuously to the population is modelled. The environment alternates in its character being hostile and favourable.The favourable periods are independently and identically distributed random variables and during the constantharsh periods all the adults in the population are wiped out While the existing models tacitly assume the environmental period to be much smaller than the biological period ρ, our modelling enables us to consider the two periods to be of comparable scale. In such a case, apart from the various statistical characteristics of interest derived, we show that the average extinction time increases with increasing duration of the disturbance, a result which is counter-intutive.Numerical evaluation of the time for extinction for certain values of the parameters involved are made. 相似文献
992.
Miguel A. Aguilar-Méndez Eduardo San Martín-Martínez Lesli Ortega-Arroyo Georgina Cobián-Portillo Esther Sánchez-Espíndola 《Journal of nanoparticle research》2011,13(6):2525-2532
Colloidal silver nanoparticles were synthesized by reducing silver nitrate solutions with glucose, in the presence of gelatin
as capping agent. The obtained nanoparticles were characterized by means of UV–Vis spectroscopy, transmission electron microscopy
(TEM), and Fourier transform infrared (FTIR) spectroscopy. The response surface methodology (RSM) was also used to determine
the influence of the variables on the size of the nanoparticles. The antifungal activity of the silver nanoparticles was evaluated
on the phytopathogen Colletotrichum gloesporioides, which causes anthracnose in a wide range of fruits. The UV–Vis spectra indicated the formation of silver nanoparticles preferably
spherical and of relatively small size (<20 nm). The above-mentioned was confirmed by TEM, observing a size distribution of
5–24 nm. According to RSM the synthesis variables influenced on the size of the silver nanoparticles. By means of FTIR spectroscopy
it was determined that gelatin, through their amide and hydroxyl groups, interacts with nanoparticles preventing their agglomeration.
The growth of C. gloesporioides in the presence of silver nanoparticles was significantly delayed in a dose dependent manner. 相似文献
993.
Jie Chen Wei Yan Esther J. Townsend Jiangtao Feng Long Pan Veronica DelAngelHernandez Charl F. J. Faul 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(34):11841-11845
Simple inorganic salts are used to tune N‐containing conjugated microporous polymers (CMPs) synthesized by Buchwald–Hartwig (BH) cross‐coupling reactions. Poly(triphenylamine), PTPA, initially shows a broad distribution of micropores, mesopores, and macropores. However, the addition of inorganic salts affects all porous network properties significantly: the pore size distribution is narrowed to the microporous range only, mimicking COFs and MOFs; the BET surface area is radically improved from 58 m2 g?1 to 1152 m2 g?1; and variations of the anion and cation sizes are used to fine‐tune the surface area of PTPA, with the surface area showing a gradual decrease with an increase in the ionic radius of salts. The effect of the salt on the physical properties of the polymer is attributed to adjusting and optimizing the Hansen solubility parameters (HSPs) of solvents for the growing polymer, and named the Beijing–Xi'an Jiaotong (BXJ) method. 相似文献
994.
JPC – Journal of Planar Chromatography – Modern TLC - Enicostemma littorale (Chota-Chirayata or Mamejava) is a glabrous perennial herb belonging to the family Gentianaceae. This plant... 相似文献
995.
Dr. Anna Aviñó Dr. Ugutz Unzueta Dr. María Virtudes Céspedes Dr. Isolda Casanova Dr. Esther Vázquez Prof. Dr. Antonio Villaverde Prof. Dr. Ramon Mangues Prof. Dr. Ramon Eritja 《ChemistryOpen》2019,8(3):382-387
Oligonucleotide-protein conjugates have important applications in biomedicine. Simple and efficient methods are described for the preparation of these conjugates. Specifically, we describe a new method in which a bifunctional linker is attached to thiol-oligonucleotide to generate a reactive intermediate that is used to link to the protein. Having similar conjugation efficacy compared with the classical method in which the bifunctional linker is attached first to the protein, this new approach produces significantly more active conjugates with higher batch to batch reproducibility. In a second approach, direct conjugation is proposed using oligonucleotides carrying carboxyl groups. These methodologies have been applied to prepare nanoconjugates of an engineered nanoparticle protein carrying a T22 peptide with affinity for the CXCR4 chemokine receptor and oligomers of the antiproliferative nucleotide 2’-deoxy-5-fluorouridine in a very efficient way. The protocols have potential uses for the functionalization of proteins, amino-containing polymers or amino-lipids in order to produce complex therapeutic nucleic acid delivery systems. 相似文献
996.
Seth Madren Will McElroy Kristin Schultz-Kuszak Boris Boumajny Yao Shu Sabine Sautter Helen C. Zhao Abby Schadock-Hewitt Chris Chumsae Nancy Ball Xiaoying Zhang Kimberly Rish Shukui Zhang Christine Wurm Sumin Cai Scott P. Bauer Cinzia Stella Laura Zheng Brian Roper David A. Michels Gang Wu Bostjan Kocjan Matej Birk Simon Erik Erdmann Xiaoping He Brad Whittaker Yvonne Song Hannah Barrett Kevin Strozyk Ye Jing Long Huang Vishal Mhatre Paul McLean Tiantian Yu Huijuan Yang Minna Mattila 《Electrophoresis》2022,43(9-10):1050-1058
An international team spanning 19 sites across 18 biopharmaceutical and in vitro diagnostics companies in the United States, Europe, and China, along with one regulatory agency, was formed to compare the precision and robustness of imaged CIEF (ICIEF) for the charge heterogeneity analysis of the National Institute of Standards and Technology (NIST) mAb and a rhPD-L1-Fc fusion protein on the iCE3 and the Maurice instruments. This information has been requested to help companies better understand how these instruments compare and how to transition ICIEF methods from iCE3 to the Maurice instrument. The different laboratories performed ICIEF on the NIST mAb and rhPD-L1-Fc with both the iCE3 and Maurice using analytical methods specifically developed for each of the molecules. After processing the electropherograms, statistical evaluation of the data was performed to determine consistencies within and between laboratory and outlying information. The apparent isoelectric point (pI) data generated, based on two-point calibration, for the main isoform of the NIST mAb showed high precision between laboratories, with RSD values of less than 0.3% on both instruments. The SDs for the NIST mAb and the rhPD-L1-Fc charged variants percent peak area values for both instruments are less than 1.02% across different laboratories. These results validate the appropriate use of both the iCE3 and Maurice for ICIEF in the biopharmaceutical industry in support of process development and regulatory submissions of biotherapeutic molecules. Further, the data comparability between the iCE3 and Maurice illustrates that the Maurice platform is a next-generation replacement for the iCE3 that provides comparable data. 相似文献
997.
998.
999.
Nancy C. Forero-Martinez Ha-Linh Thi Le Holger Vach 《Plasma Chemistry and Plasma Processing》2014,34(3):535-543
We theoretically predict that low pressure silane/hydrogen plasmas may present the ideal venue for the fabrication of a new nanostructured silicon material with strong aromatic properties. Precisely controlling the ratio of atomic and molecular hydrogen concentrations during the growth of hydrogenated silicon clusters in a pulsed plasma enhanced chemical vapor deposition reactor will allow us to “steer” the growth toward over-coordinated silicon nanocrystals that reveal aromatic properties as strong as those of benzene. In addition, those pure silicon nanocrystals demonstrate optical, electrical, and mechanical characteristics that could so far only be obtained by adding toxic or expensive elements (as PbS, PbSe, CdS, CdSe, or Au) in the cluster structure. Due to their light absorption not only in the ultraviolet, but also in the visible and the infrared spectrum, they might, for instance, play a major role for photovoltaic devices or in the hyperthermal treatment of cancer. 相似文献
1000.
Esther C. Y. Woon Anthony Tumber Akane Kawamura Lars Hillringhaus Wei Ge Nathan R. Rose Jerome H. Y. Ma Mun Chiang Chan Louise J. Walport Ka Hing Che Stanley S. Ng Brian D. Marsden Udo Oppermann Michael A. McDonough Christopher J. Schofield 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2012,124(7):1663-1666