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We examined the use of monolithic capillary columns prepared via ring-opening metathesis polymerization (ROMP) for peptide separation in voltage-assisted capillary LC (voltage-assisted CLC). In order to demonstrate their potential for peptide separation, ROMP-derived monoliths with RP properties were prepared. The preparation procedure of monoliths was transferred from ROMP monoliths optimized for CLC. ROMP monoliths were synthesized within the confines of 200 microm id fused-silica capillaries with a length of 37 cm. After optimization of the chromatographic conditions, the separation performance was tested using a well-defined set of artificial peptides as well as two peptidic mixtures resulting from a tryptic digest of BSA as well as a collagenase digest of collagen. ROMP monoliths showed comparable performance to other monolithic separation media in voltage-assisted CLC published so far. Therefore, we conclude that by optimizing the composition of the ROMP monoliths as well as by using the controlled manner of their functionalization, ROMP monoliths bear a great potential in CLC and CEC. 相似文献
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P. Hoffmann V. K. Karandashev T. Sinner H. M. Ortner 《Analytical and bioanalytical chemistry》1997,357(8):1142-1148
Data are reported for a first measurement campaign for a great number of cations (the range of concentrations for main components
is given in ng/mL: Na:<70–880; Mg: 12–160; Al:<7–120; K: 200–1600; NH4
+: 2500–9000; Ca: 300–2500; Fe:<140–1200; Zn: 20–320) and anions (HCOO-: 100–1800; CH3COO-: 400–14500; C2O2-
4: <100–460; NO-
2: <20–55; NO-
3: 660–9900; SO2-
3:<100–1150; SO4
2-: 450–19700; Cl-: 170–3200) in rain and snow samples of the Chernogolovka region 80 km northeast of the centre of Moscow. These data serve
as a first assessment of the situation of the atmosphere in this region. For the determination of fluoride, formate, acetate,
nitrite, bromide, nitrate, sulfite, and sulfate by IC, a relevant development of the method was carried out. For some metallic
cations, a critical quality control was achieved by parallel measurements with ICP-MS, TXRF, and IC. Furthermore, time resolved
measurements were performed for a rain event. Filtration experiments were undertaken to differentiate between the presence
of a series of elements and species in liquid or solid state in the collected aqueous samples.
Received: 25 July 1996 / Revised: 26 September 1996 / Accepted: 13 October 1996 相似文献
4.
Claude Sinner Cheyenne Ziegler Yun Ho Jung Xianli Jiang Faruck Morcos 《Entropy (Basel, Switzerland)》2021,23(2)
Two-component systems (TCS) are signaling machinery that consist of a histidine kinases (HK) and response regulator (RR). When an environmental change is detected, the HK phosphorylates its cognate response regulator (RR). While cognate interactions were considered orthogonal, experimental evidence shows the prevalence of crosstalk interactions between non-cognate HK–RR pairs. Currently, crosstalk interactions have been demonstrated for TCS proteins in a limited number of organisms. By providing specificity predictions across entire TCS networks for a large variety of organisms, the ELIHKSIR web server assists users in identifying interactions for TCS proteins and their mutants. To generate specificity scores, a global probabilistic model was used to identify interfacial couplings and local fields from sequence information. These couplings and local fields were then used to construct Hamiltonian scores for positions with encoded specificity, resulting in the specificity score. These methods were applied to 6676 organisms available on the ELIHKSIR web server. Due to the ability to mutate proteins and display the resulting network changes, there are nearly endless combinations of TCS networks to analyze using ELIHKSIR. The functionality of ELIHKSIR allows users to perform a variety of TCS network analyses and visualizations to support TCS research efforts. 相似文献
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Sinner FM Gatschelhofer C Mautner A Magnes C Buchmeiser MR Pieber TR 《Journal of chromatography. A》2008,1191(1-2):274-281
Monolithic capillary columns were prepared via ring-opening metathesis polymerization (ROMP) using norborn-2-ene (NBE) and 1, 4, 4a, 5, 8, 8a-hexahydro-1, 4, 5, 8-exo,endo-dimethanonaphthalene (DMN-H6) as monomers. The monolithic polymer was copolymerized with Grubbs-type initiator RuCl(2)(PCy(3))(2)(CHPh) and a suitable porogenic system within the confines of fused silica capillaries of different inner diameter (I.D.). The first part of the study focused on batch-to-batch reproducibility of ROMP-derived capillary monoliths. Capillary monoliths of 200 microm I.D. showed good reproducibility in terms of retention times, with relative standard deviations (RSD) of 1.9% for proteins and 2.2% for peptides. However, the separately synthesized capillary monoliths revealed pronounced variation in back pressure with RSD values of up to 31%. These variations were considerably reduced by cooling of the capillaries during polymerization. Using this optimized preparation procedure capillary monoliths of 100 and 50 microm I.D. were synthesized and the effects of scaling down the column I.D. on the morphology and on the reproducibility of the polymerization process were investigated. In the second part, the applicability of ROMP-derived capillary monoliths to a separation problem common in medical research was assessed. A 200 microm I.D. monolithic column demonstrated excellent separation behavior for insulin and various insulin analogs, showing equivalent separation performance to Vydac C4 and Zorbax C3-based stationary phases. Moreover, the high permeability of monoliths enabled chromatographic separations at higher flow rates, which shortened analysis time to about one third. For the analysis of insulin in human biofluid samples, enhanced sensitivity was achieved by using a 50 microm I.D. ROMP-derived monolith. 相似文献
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Schlemmer B Gatschelhofer C Pieber TR Sinner FM Buchmeiser MR 《Journal of chromatography. A》2006,1132(1-2):124-131
Monolithic columns for capillary HPLC were prepared via ring-opening metathesis polymerization (ROMP) from cis-cyclooctene (COE), tris(cyclooct-4-enyl-1-oxy)methylsilane (CL) as monomers, 2-propanol and toluene as porogens and RuCl(2)(Py)(2)(IMesH(2))(CHC(6)H(5)) (Py=pyridine, IMesH(2)=1,3-dimesityl-4,5-dihydroimidazolin-2-ylidene) as initiator within the confines of 200 microm i.d. fused silica columns. For evaluation of the novel monolithic capillary HPLC columns, a protein standard consisting of six proteins in the molecular weight range of 5800-66000 g/mol, i.e. ribonuclease A, insulin, albumin, lysozyme, myoglobin and beta-lactoglobulin, was used. Reproducibility of synthesis was checked by determining the relative standard deviation (RSD) in retention times (t(R)), which was found to be in the range of 2.9-3.9% for all analytes. Variations in polymer kinetics were realized by adding different amounts of free pyridine and had a significant influence on the monolith's morphology, the backpressure and retention times. On the contrary, variations in monomer content and COE to CL ratio showed only minor changes on these parameters. Long-term stability of 1000 runs at 50 degrees C showed excellent stability of the columns and no significant alteration in separation performance was observed in combination with slightly decreased retention times (approx. 1.6-7.2% for all analytes). 相似文献
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P. Hoffmann V. K. Karandashev T. Sinner H. M. Ortner 《Fresenius' Journal of Analytical Chemistry》1997,357(8):1142-1148
Data are reported for a first measurement campaign for a great number of cations (the range of concentrations for main components
is given in ng/mL: Na:<70–880; Mg: 12–160; Al:<7–120; K: 200–1600; NH4
+: 2500–9000; Ca: 300–2500; Fe:<140–1200; Zn: 20–320) and anions (HCOO-: 100–1800; CH3COO-: 400–14500; C2O2-
4: <100–460; NO-
2: <20–55; NO-
3: 660–9900; SO2-
3:<100–1150; SO4
2-: 450–19700; Cl-: 170–3200) in rain and snow samples of the Chernogolovka region 80 km northeast of the centre of Moscow. These data serve
as a first assessment of the situation of the atmosphere in this region. For the determination of fluoride, formate, acetate,
nitrite, bromide, nitrate, sulfite, and sulfate by IC, a relevant development of the method was carried out. For some metallic
cations, a critical quality control was achieved by parallel measurements with ICP-MS, TXRF, and IC. Furthermore, time resolved
measurements were performed for a rain event. Filtration experiments were undertaken to differentiate between the presence
of a series of elements and species in liquid or solid state in the collected aqueous samples.
Received: 25 July 1996 / Revised: 26 September 1996 / Accepted: 13 October 1996 相似文献
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P. Hoffmann T. Sinner A. N. Dedik V. K. Karandashev A. A. Malyshev S. Weber H. M. Ortner 《Fresenius' Journal of Analytical Chemistry》1994,350(1-2):34-37
Preliminary results are summarized from experiments in which the chemical species of Fe have been determined in atmospheric aqueous and particulate samples. Filtration, ultrafiltration, ion chromatography, extraction, and Mössbauer spectrometry have been used for their characterization. In nearly all experiments the values scattered broadly and this effect is discussed in terms of responsible parameters.On leave from the Ukrainian Academy of Sciences, Institute of Metal Physics, Sumy Department of Applied Physics, 244000 Sumy, UkraineOn leave from the Russian Academy of Sciences, Institute of Microelectronics, Technology and High Purity Materials, 142432 Chernogolovka, Moscow District, Russia 相似文献
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Antonio?Hill Andreas?Sinner Klaus?ZieglerEmail author 《The European Physical Journal B - Condensed Matter and Complex Systems》2013,86(2):53
We calculate the optical Hall conductivity within the Kubo formalism for systems with gapped spectral nodes, where the latter have a power-law dispersion with exponent n. The optical conductivity is proportional to n and there is a characteristic logarithmic singularity as the frequency approaches the gap energy. The optical Hall conductivity is almost unaffected by thermal fluctuations and disorder for n = 1, whereas disorder has a stronger effect on transport properties if n = 2. 相似文献