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91.
Soft single-photon ionisation (SPI)–time-of-flight mass spectrometry (TOFMS) has been used to investigate the effect of different
cigarette-lighting devices on the chemical composition of the mainstream smoke from the first cigarette puff. Lighting devices
examined were a Borgwaldt electric lighter, a propane/butane gas lighter, a match, a candle, and the burning zone of another
cigarette. To eliminate the effects of the different masses of tobacco burnt by use of the different lighting methods a normalisation
procedure was performed which enabled investigation of changes in the chemical patterns of the resulting smoke. When another
cigarette was used as the lighting device, elevated levels of ammonia and other nitrogen-containing substances were observed.
These are high in the sidestream smoke of the cigarette used for lighting and would be drawn into the mainstream smoke of
the cigarette being lit. In contrast, smoke from the cigarette lit by the electric lighter contained slightly higher normalised
amounts of isoprene. Lighting the cigarette by use of a candle resulted in larger amounts of substances, e.g. benzene, which
most probably originated from thermal decomposition of wax. The composition of the first puff of smoke obtained by use of
the three lighting methods with open flames (gas lighter, match, and candle) was usually similar whereas the composition of
the smoke produced by use of the electric lighter and the cigarette as the lighter were more unique. The chemical patterns
generated by the different lighting devices could, however, be separated by principal-component analyses. Two additional test
series were also studied. In the first the cigarette was lit with an electric lighter, then extinguished, the ash was cut
off, and the cigarette was re-lit. In the second the cigarette was heated in an oven to 80 °C for 5 min before being lit.
These treatments did not result in changes in the chemical composition compared with cigarettes lit in the ordinary way.
Figure Time-of-flight mass spectrometry (TOFMS) has been used to investigate the effect of different cigarette-lighting devices on
the chemical composition of the mainstream smoke from the first cigarette puff 相似文献
92.
Philip A. Baker Andrew F. Coffey Roger Epton Tony Johnson Edward J. Mole 《Macromolecular Symposia》1988,19(1):79-91
2, 4-Dinitrophenyl-L-phenylalanine has been coupled to L-, D-, and DL-amino acid phenyl esters pendant upon a polymer matrix. The esters had been prepared by di-isopropylcarbodiimide-mediated condensation, catalyzed by 4-dimethylaminopyridine. Reverse phase high pressure liquid chromatography (HPLC), using elution solvents consisting of 10 vol.-% trifluoroacetic acid in water/acetonitrile mixtures, has been used to investigate the 2,4-dinitrophenyl L-L and L-D dipeptide mixtures obtained on hydrazinolysis of each of the dipeptide-matrix assemblies. ‘Hydrazinolysis-HPLC’ has been used also to determine intermediate peptide homogeneity in ultra-high load solid (gel) phase synthesis with Boc amino acids. Cross-linked poly(N-[2-(4-hydroxyphenyl)ethyl]acrylamide) and two derived polymers incorporating spacer groups have been used as supports. The spacer groups made possible peptide C-terminal attachment by either HF-labile benzyl ester or HF-labile cyclohexyl ester bonds, while still incorporating the phenolic ester linkage susceptible to rapid hydrazinolytic scission. 相似文献
93.
Alyssa B. Sanders Jacob T. Zangaro Nakoa K. Webber Ryan P. Calhoun Elizabeth A. Richards Samuel L. Ricci Hannah M. Work Daniel D. Yang Kaitlyn R. Casey Joseph C. Iovine Gabriela Baker Taylor V. Douglas Sierra B. Dutko Thomas J. Fasano Sarah A. Lofland Ashley A. Rajan Mihaela A. Vasile Benjamin R. Carone Nathaniel V. Nucci 《Molecules (Basel, Switzerland)》2022,27(5)
Despite considerable advances in recent years, challenges in delivery and storage of biological drugs persist and may delay or prohibit their clinical application. Though nanoparticle-based approaches for small molecule drug encapsulation are mature, encapsulation of proteins remains problematic due to destabilization of the protein. Reverse micelles composed of decylmonoacyl glycerol (10MAG) and lauryldimethylamino-N-oxide (LDAO) in low-viscosity alkanes have been shown to preserve the structure and stability of a wide range of biological macromolecules. Here, we present a first step on developing this system as a future platform for storage and delivery of biological drugs by replacing the non-biocompatible alkane solvent with solvents currently used in small molecule delivery systems. Using a novel screening approach, we performed a comprehensive evaluation of the 10MAG/LDAO system using two preparation methods across seven biocompatible solvents with analysis of toxicity and encapsulation efficiency for each solvent. By using an inexpensive hydrophilic small molecule to test a wide range of conditions, we identify optimal solvent properties for further development. We validate the predictions from this screen with preliminary protein encapsulation tests. The insight provided lays the foundation for further development of this system toward long-term room-temperature storage of biologics or toward water-in-oil-in-water biologic delivery systems. 相似文献
94.
Wayne E. Baker 《The Journal of mathematical sociology》2013,37(2):191-223
In the classic blockmodel formulation, a social network among members of a population with n actors and k relations (types of tie) is arrayed as k n X n matrices. Though this is a three‐dimensional data structure, it is typically reduced to a two‐way analysis. In this paper, a three‐way procedure for analyzing multigraph data is developed. Specifically, in addition to applying the rule of structural equivalence to collapse actors, it is also applied to the relations (the third dimension), and structurally equivalent sets of relations are collapsed. The result is a three‐dimensional blockmodel (image) of social structure that is a more parsimonious representation of social structure than the classic two‐dimensional blockmodel images. The three‐dimensional approach is illustrated by application to three case studies: Homan's Bank Wiring Room, Sampson's monastery, and a local economy of hospital services. The structural equivalence approach to relations is further explored by applying it to the individual‐level Liking and Antagonism relations and their compounds (of length four or less) in the Bank Wiring Room. This application demonstrates that the structural equivalence approach can be used to identify equality equations for primitive and compound relations. 相似文献
95.
96.
97.
George A. Baker Jr. 《General Relativity and Gravitation》2002,34(6):767-791
Recent experimental results from supernovae Ia observations have been interpreted to show that the rate of expansion of the universe is increasing. Other recent experimental results find strong indications that the universe is flat. In this paper, I investigate some solutions of Einstein's field equations which go smoothly between Schwarzschild's relativistic gravitational solution near a mass concentration to the Friedmann-Lemaître expanding universe solution. In particular, the static, curved-space extension of the Lemaître-Schwarzschild solution in vacuum is given. Uniqueness conditions are discussed. One of these metrics preserves the cosmological equation. We find that when the rate of expansion of the universe is increasing, space is broken up into domains of attraction. Outside a domain of attraction, the expansion of the universe is strong enough to accelerate a test particle away from the domain boundary. I give a domain-size–mass relationship. This relationship may very well be important to our understanding of the large scale structure of the universe. 相似文献
98.
99.
[formula: see text] A chiral rhodium complex, (R)-Cp*RhCl[(1S,2S)-p-TsNCH(C6H5)CH(C6H5)NH2] (1a, (S,S)-Cp*RhClTsDPEN), generated from [Cp*RhCl2]2 and (1S,2S)-N-p-toluenesulfonyl-1,2-diphenylethylenediamine [(S,S)-TsDPEN], and its enantiomer 1b were found to provide superior catalysts for the rapid, high-yielding, asymmetric transfer hydrogenation of some heterocyclic imines, using an HCO2H-Et3N azeotrope as the hydrogen source. 相似文献
100.