Capillary electrochromatography (CEC) monolithic columns were prepared following a two-step synthetic pathway based on (i) UV-induced in situ radical polymerization of N-acryloxysuccinimide (NAS) and ethylene dimethacrylate (EDMA) and (ii) in situ functionalization of the NAS-containing monolithic matrix with various alkylamines. The first synthetic step was performed using toluene as a porogenic solvent. The successful grafting of the alkylamines onto the reactive matrix was confirmed on the basis of qualitative analysis of Raman spectra recorded before and after the chemical modification step. All the electrochromatographic results indicate a strong dependence of the retention, efficiency and selectivity of the monolithic columns on small variations of mobile phase composition and nature of the grafted aliphatic selector in agreement with the typical reversed-phase behaviour. Van Deemter plots for a series of alkylbenzene homologues injected on a column bearing hexyl-segments as side chains are also presented.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/j.chroma.2007.03.039 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Regioselective 1,4-Addition of P(O)-H Species to In SituFormed 1-Benzopyrylium Ion from C3-Substituted 2-Chromene Hemiketals to Construct C3-Functionalized C4-Phosphorylated 4-Chromenes.
J Org Chem
January 2025
Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, School of Pharmacy, Chengdu University, 2025 Chengluo Avenue, Chengdu 610016, P.R. China.
Herein, we report the first example that P(O)-H species including -phosphonates and -phosphine oxides could participate in a highly regioselective 1,4-addition to in situ generated 1-benzopyrylium ion from C3-substituted 2-chromene hemiketals, which provides a brand-new and effective approach for the synthesis of C4-phosphorylated 4-chromenes with diverse C3-functionality (ketone, ester, sulfonyl, aryl, and alkyl groups). In total, the reaction features the use of inexpensive Zn(ClO)·6HO as a catalyst, low catalyst loading (only 5 mol %), mild reaction conditions (60 °C, 10 min to 24 h), and broad substrate scope (46 examples) as well as good to high yields (>90% yield on average). More importantly, mechanistic experiments demonstrated the essential role of the C3-substituent on 2-chromene hemiketals in stabilizing the in situ generated 1-benzopyrylium ion and the regioselective 1,4-addition control.
View Article and Find Full Text PDFGenomic Characterization and Prognostic Significance of Human Epidermal Growth Factor Receptor 2-Low, Hormone Receptor-Positive, Early Breast Cancers From the BIG 1-98 and SOFT Clinical Trials.
JCO Precis Oncol
January 2025
Department of Medical Oncology, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.
Purpose: To investigate whether hormone receptor-positive, human epidermal growth factor receptor 2-low (HR+HER2-low) versus HR+HER2-zero early breast cancers have distinct genomic and clinical characteristics.
Methods: This study included HR+, HER2-negative early breast cancers from patients enrolled in the phase III, randomized BIG 1-98 and SOFT clinical trials that had undergone tumor genomic sequencing. Tumors were classified HR+HER2-low if they had a centrally reviewed HER2 immunohistochemistry (IHC) score of 1+ or 2+ with negative in situ hybridization and HR+HER2-zero if they had an HER2 IHC score of 0.
The spatial biology of HIV infection.
PLoS Pathog
January 2025
The Westmead Institute for Medical Research, Westmead, New South Wales, Australia.
HIV infection implicates a spectrum of tissues in the human body starting with viral transmission in the anogenital tract and subsequently persisting in lymphoid tissues and brain. Though studies using isolated cells have contributed significantly towards our understanding of HIV infection, the tissue microenvironment is characterised by a complex interplay of a range of factors, all of which can influence the course of infection but are otherwise missed in ex vivo studies. To address this knowledge gap, it is necessary to investigate the dynamics of infection and the host immune response in situ using imaging-based approaches.
View Article and Find Full Text PDFLow oxygen but dynamic marine redox conditions permitted the Cambrian Radiation.
Sci Adv
January 2025
School of GeoSciences, University of Edinburgh, James Hutton Road, Edinburgh EH9 3FE, UK.
Whether metazoan diversification during the Cambrian Radiation was driven by increased marine oxygenation remains highly debated. Repeated global oceanic oxygenation events have been inferred during this interval, but the degree of shallow marine oxygenation and its relationship to biodiversification and clade appearance remain uncertain. To resolve this, we interrogate an interval from ~527 to 519 Ma, encompassing multiple proposed global oceanic oxygenation events.
View Article and Find Full Text PDFAn ancient apical patterning system sets the position of the forebrain in chordates.
Sci Adv
January 2025
Department of Zoology, University of Cambridge, Cambridge, UK.
The evolutionary origin of the vertebrate brain remains a major subject of debate, as its development from a dorsal tubular neuroepithelium is unique to chordates. To shed light on the evolutionary emergence of the vertebrate brain, we compared anterior neuroectoderm development across deuterostome species, using available single-cell datasets from sea urchin, amphioxus, and zebrafish embryos. We identified a conserved gene co-expression module, comparable to the anterior gene regulatory network (aGRN) controlling apical organ development in ambulacrarians, and spatially mapped it by multiplexed in situ hybridization to the developing retina and hypothalamus of chordates.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!