Signaling Recognition Events with Fluorescent Sensors and Switches.

FACTS An officer in Midvale, Utah was doing some paperwork in his patrol car when he was approached by man, later identified as Nitokalisi Fonua (hereinafter, “Nick”). Nick “looked suspicious,” mainly because he was “jittery, looking around and appeared to be very nervous.” Nick’s suspicion rating jumped dramatically when, for no apparent reason, he informed the officer he had stolen a white GMC Blazer, which he had parked nearby. Naturally, the officer asked Nick if he would show him the Blazer, and Nick said sure. When they located the Blazer, the officer walked over and looked inside. The first thing he saw was a sawed-off shotgun on the back seat. Then he noticed some markings on the shotgun, “markings that looked gang-related.” Nick told the officer that the key to the Blazer was inside his motel room at the Days Inn. Also in the room, he said, were his “cousins,” meaning “people he knows from the streets.” The officer asked Nick “if we could obtain the keys to the vehicle so we could turn those back over to the owner.” Nick said the keys “were in the room somewhere” and that he “didn’t care” if the officer went in and retrieved them. Nick also gave the officer his key to the room. When backup arrived at the motel, officers knocked on the door which was opened by a man named Vake. There were two other occupants: a woman and Kimoana, the defendant. By this time, the officers were aware that Kimoana—not Nick—had rented the room. The first thing the officers saw as the door opened was the woman pointing “an unidentified black object” at the wall. Concerned for their safety, they ordered the occupants to “show their hands.” Then they pat searched them. Finding no weapons (the “unidentified black object” was a television remote control), they holstered their guns. Although the officers already had Nick’s consent to search the room, they sought and obtained consent from Vake. During the search, they found a “long-barreled revolver” under a mattress. As the result, Kimoana was convicted of being a felon in possession of a firearm.

United States V. _____

Organic residue analysis utilizes analytical organic chemical techniques to identify the nature and origins of organic remains that cannot be characterized using traditional techniques of archaeological investigation (because they are either amorphous or invisible). The field is founded upon the principle that the biomolecular, or biochemical, components of organic materials associated with human activity survive in a wide variety of locations and deposits at archaeological sites. The archaeological information contained in organic residues is represented by the biomolecular components of the natural products that contribute to the formation of a given residue. By applying appropriate separation (chromatographic) and identification (mass spectrometric) techniques, the preserved, and altered, biomolecular components of such residues can be revealed. Once identified, the Archaeological Biomarker Concept can be applied, wherein the structure and even isotopic composition(s) of a given biomolecule or suite of biomolecules (the ‘chemical fingerprint’) can be related to the compositions of organisms exploited by humans in the past. As the organic residue field emerges from its pre-paradigmatic phase, and the organic residue revolution gathers pace, the way is open for challenging many long-held archaeological hypotheses and offering new perspectives on the study of human activity in the past.

Organic residue analysis in archaeology: the archaeological biomarker revolution*

The factors affecting host-guest complexation between the molecular container compound cucurbit[6]uril (CB6) and various guests in aqueous solution are studied, and a detailed complexation mechanism in the presence of cations is derived. The formation of the supramolecular complex is studied in detail for cyclohexylmethylammonium ion as guest. The kinetics and thermodynamics of complexation is monitored by NMR as a function of temperature, salt concentration, and cation size. The binding constants and the ingression rate constants decrease with increasing salt concentration and cation-binding constant, in agreement with a competitive binding of the ammonium site of the guest and the metal cation with the ureido carbonyl portals of CB6. Studies as a function of guest size indicate that the effective container volume of the CB6 cavity is approximately 105 A(3). It is suggested that larger guests are excluded for two reasons: a high activation barrier for ingression imposed by the tight CB6 portals and a destabilization of the complex due to steric repulsion inside. For example, in the case of the nearly spherical azoalkane homologues 2,3-diazabicyclo[2.2.1]hept-2-ene (DBH, volume ca. 96 A(3)) and 2,3-diazabicyclo[2.2.2]oct-2-ene (DBO, volume ca. 110 A(3)), the former forms the CB6 complex promptly with a sizable binding constant (1300 M(-1)), while the latter does not form a complex even after several months at optimized complexation conditions. Molecular mechanics calculations are performed for several CB6/guest complexes. A qualitative agreement is found between experimental and calculated activation energies for ingression as a function of both guest size and state of protonation. The potential role of constrictive binding by CB6 is discussed.

Mechanism of host-guest complexation by cucurbituril.

Carceplexes and Hemicarceplexes

The sources and structures of dyes used to colour Western historical textiles are described in this tutorial review. Most blue and purple colours were derived from indigo—obtained either from woad or from the indigo plant—though some other sources (e.g. shellfish and lichens) were used. Reds were often anthraquinone derivatives obtained from plants or insects. Yellows were almost always flavonoid derivatives obtained from a variety of plant species. Most other colours were produced by over-dyeing—e.g. greens were obtained by over-dyeing a blue with a yellow dye. Direct analysis of dyes isolated from artefacts allows comparison with the historical record.

/pdf/the-natural-constituents-of-historical-textile-dyes-1fcbhls10b.pdf

The natural constituents of historical textile dyes

https://www.pure.ed.ac.uk/ws/files/10338249/Negative_ion_ESI_MS_analysis_of_natural_yellow_dye_flavonoids_An_isotopic_labelling_study.pdf

Negative ion ESI–MS analysis of natural yellow dye flavonoids—An isotopic labelling study

Supramolecular photochemistry and photophysics. biacetyl imprisoned in a hemicarcerand

Indigo has a powerful hold on the imagination - as evidenced by the traditional picture of Ancient Britons coloured blue with woad indigo - but, until now, the actual application of the dye and possible explanations underlying the practice have rarely been considered. The dyestuff is equally fascinating to the scientist, to Adolf von Baeyer in the 19th century, or to the modern chemist using modern instrumental methods for its characterisation. Indigoid dyes are not the only blues and purples, however, lichen dyes have an equally long history and their inconspicuous sources, found in many, often inhospitable, habitats, are no less intriguing, if difficult to categorise. Perhaps the most humble colouring matter is mud, but this, too, has a biological aspect to its use.

These and other naturally occuring organic colouring matters were among the subjects for discussion at the 18th Meeting of Dyes in History and Archaeology, held in Brussels in 1999. The textiles and other artefacts coloured with the dyes are no less interesting and varied. Romanian and Polish textiles and, as the cover illustrates, Japanese ukiyo-e prints are only examples of the possible uses discussed in this book.

Photo-oxidation products of Quercetin and Morin as markers for the characterisation of natural flavonoid yellow dyes in Ancient textiles dyes

Lead white is a man-made white pigment commonly used in works of art. In this study, the possibility of radiocarbon dating lead white pigments alone and in oil paints was explored using well-dated lead white pigments and paints. Resulting C-14 ages on lead white pigments produced following the traditional stack process, where carbonate groups results from the incorporation of CO2 originating from fermentation, matched the production years, while radiocarbon dating of lead white made using other industrial processes indicate that C-14 depleted CO2 was used in their production. The method was applied to two case studies, where lead carbonate samples were dated in two oil paintings, one Baroque and one from the 20th century. We hereby show that the lead white pigment can be dated by C-14 and used as proxy for the time of creation of an artwork. Additionally, a two-step method was developed to allow C-14 analysis of both the lead white pigment and oil binder from the same sample. A single lead white paint sample can yield two distinct radiocarbon ages, one from the carbonate and one from the natural organic binder. This study thus proposes new strategies for C-14 dating of artworks.

/pdf/selective-dating-of-paint-components-radiocarbon-dating-of-hcrmrv67j2.pdf

Ester S.B. Ferreira

Papers

The natural constituents of historical textile dyes

Negative ion ESI–MS analysis of natural yellow dye flavonoids—An isotopic labelling study

Supramolecular photochemistry and photophysics. biacetyl imprisoned in a hemicarcerand

Photo-oxidation products of Quercetin and Morin as markers for the characterisation of natural flavonoid yellow dyes in Ancient textiles dyes

Selective dating of paint components: Radiocarbon dating of lead white pigment