The yield of 3-deoxy-4-sulphopentosulose in the sulphite inhibited non-enzymic browning of ascorbic acid

The ion exchange behaviour of 3-deoxy-4-sulphopentosulose is markedly influenced by the presence of hydrogen sulphite ion, the dihydroxysulphonate being held more firmly on a strongly basic resin than the free dicarbonylic product. The apparent formation of other sulphonates in model ascorbic acid/glycine/HSO₃- reactions is explained in terms of this ion exchange behaviour and the major reaction product is 3-deoxy-4-sulphopentosulose in 75 % yield. In foods, the yields of this sulphonate and also of 3-deoxy-4-sulphohexosulose are now regarded as true indicators of the extent of the fate of sulphur dioxide by way of its inhibition of non-enzymic browning reactions.     

SOLVENT EXTRACTION OF RADIUM AND BARIUM CATIONS INTO CHLOROFORM BY A LIPOPHILIC ACYCLIC POLYETHER DICARBOXYLIC ACID

The lipophilic acyclic polyether carboxylic acid bls-l,8(2 -carboxy-3-naphthoxy)-3,6-dioxaoctane exhibits selectivity for Ra²⁺ over Ba²⁺ in competitive extractions into chloroform. Solubility characteristics of the compound suggest that the addition of branched alkyl substituents would be required to make it a practical separation agent.     

mu-Opioid receptor activates signaling pathways implicated in cell survival and translational control

The mu-opioid receptor mediates the analgesic and addictive properties of morphine. Despite the clinical importance of this G-protein-coupled receptor and many years of pharmacological research, few intracellular signaling mechanisms triggered by morphine and other mu-opioid agonists have been described. We report that mu-opioid agonists stimulate three different effectors of a phosphoinositide 3-kinase (PI3K)-dependent signaling cascade. By using a cell line stably transfected with the mu-opioid receptor cDNA, we show that the specific agonist [D-Ala2,N-Me-Phe4,Gly5-ol]enkephalin (DAMGO) stimulates the activity of Akt, a serine/threonine protein kinase implicated in protecting neurons from apoptosis. Activation of Akt by DAMGO correlates with its phosphorylation at serine 473. The selective PI3K inhibitors wortmannin and LY294002 blocked phosphorylation of this site, previously shown to be necessary for Akt enzymatic activity. DAMGO also stimulates the phosphorylation of two other downstream effectors of PI3K, the p70 S6 kinase and the repressors of mRNA translation, 4E-BP1 and 4E-BP2. Upon mu-opioid receptor stimulation, p70 S6 kinase is activated and phosphorylated at threonine 389 and at threonine 421/serine 424. Phosphorylation of p70 S6 kinase and 4E-BP1 is also repressed by PI3K inhibitors as well as by rapamycin, the selective inhibitor of FRAP/mTOR. Consistent with these findings, DAMGO-stimulated phosphorylation of 4E-BP1 impairs its ability to bind the translation initiation factor eIF-4E. These results demonstrate that the mu-opioid receptor activates signaling pathways associated with neuronal survival and translational control, two processes implicated in neuronal development and synaptic plasticity.     

Development of a novel method to measure the film thickness of cured can coatings

A new technique was developed for measuring the thickness of can coatings applied to a metal substrate. A metal disc with a known radius creates a small indent in the coating, stopping exactly when the coating thickness is cut through. The indent length is employed to calculate the coating thickness. Accurate measurement of thin films is achieved as the indent is much larger than the respective film thickness. The thickness of epoxy phenolic coatings on tinplate were measured and the results were validated by micrographic cross section analysis and by confocal laser scanning microscopy (CLSM). The coating thicknesses measured using the indentation method coincide with the film thicknesses measured by CLSM, whereas discrepancies were observed using the micrographic cross section analysis. The new technique, presented in this paper, uses simple equipment, is inexpensive, fast and easy to use, and is suitable for film thickness measurements in laboratories and production plants.     

Super-hydrophilic coatings based on silica nanoparticles

This work focuses on the use of silica nanoparticles for producing durable, transparent, and super-hydrophilic coatings on painted surfaces. Two methods were studied in detail: bottom-up approach using layer-by-layer (LbL) assemblies of hydroxylated SiO₂ nanoparticles, and top-down approach based on hybrid polymer/silica nanoparticles coatings. Of the two approaches studied, only the hybrid polymer/SiO₂ nanocomposite coatings containing 50–90%wt. SiO₂ exhibited durable super-hydrophilic surface properties less than 5° water contact and sliding angles. In the latter case, a unique micrometer-sized cracking pattern was developed. The LbL-assembled SiO₂ coatings showed a gradual degradation over time from the initial super-hydrophilic properties, indicated by the increase of the contact angles from less than 5^o to greater than 30^o after accelerated aging. To investigate the effect of environmental exposure on developing hydrophilicity, a variety of analytical methods were employed such as: atomic force microscopy, scanning electron microscopy, optical microscopy, and Fourier transform infrared. Experimental results and associated modeling indicated that the combination of micro- and nano-surface roughness and the surface chemical composition were the dominant factors affecting the durability of the hydrophilic attributes of the coatings containing silica nanoparticles.     

The reactivity of intermediates in non-enzymic browning reactions towards nitrite ion

The intermediates of non-enzymic browning reactions, 4, 5-dihydroxy-2-oxopentanal and 2-oxo-4,5,6-trihydroxyhexanal, show significant reactivity towards nitrite ion at pH 4.7 and 7.0, respectively.     

Wild times and domesticated times: the temporalities of environmental lifestyles and politics

In this paper, I explore how environmental movements and lifestyles, like all forms of human action, produce their own characteristic kinds of time. During this exploration, I introduce a number of concepts which I suggest are useful in understanding these temporalities—chronological and kairological time; linear and cyclic time; segmentation and plot; orientation and synchronisation. Whereas the environment as described by the natural sciences is one dominated by chronological, linear time, human time is also kairological, suffused with meaning and intention. The varieties of human action also produce their own distinctive temporalities—some linear, some cyclic, some oriented to external goals, some self-sufficient. The logic of kairological time also requires that we understand individual events and actions as ‘figures’ against a temporal ‘ground’—one that is characteristically organised into an overarching narrative, or broken up into distinctive time segments. Furthermore, human experience is not just situated in time, but orients itself within time—it faces ‘backwards’ into the past, ‘forwards’ into the future, or commits itself to the present. Finally, lived time is also sometimes synchronised with other times—with that of proximate or distant others, or with historical narratives of progress or decline.     

Sulphite mediated destruction of β-carotene: The partial characterisation of reaction products

Sulphite species will catalyse the destruction of β-carotene in homogeneous solution at pH 5·7 in the presence of Mn²⁺, oxygen and glycine. The products are highly oxygenated, containing from 10 to 15 oxygen atoms per β-carotene molecule. There is no evidence of extensive fragmentation or polymerisation of the carotenoid. The products appear to be widely hydrogen bonded and retain some conjugation of double bonds.