Chromatic adaptation to illumination investigated with adapting and adapted color

The state of chromatic adaptation was investigated by using the two‐room technique. This technique involves a subject in a room who looks a white board in a separate test room through a window and judges the color of the window using the elementary color naming method. When the subject room is illuminated with a colored light and the test room with a white light, the window appears to be a very vivid color, for which the apparent hue depends on the color of the subject room. The color is referred to as the adapted color. The subject also evaluated the appearance of the illumination color of the subject room, which is called the adapting color. Two types of illuminating light in the subject room, fluorescent lamps with 7 colors and LED lamps with 19 colors, were employed. The adapting and the adapted colors were plotted on a polar diagram that was used in the opponent color theory, from which the hue angles were obtained. The hue angle difference between the two colors did not appear to be 180° except for one pair of adapting and the adapted colors, which implies that chromatic adaptation does not follow the opponent color concept. An improvement was achieved to explain the results by introducing complementary colors relation between the adapting and adapted color.     

Synthesis, 3D‐QSAR,and Structural Modeling of Benzolactam Derivatives with Binding Affinity for the D2 and D3 Receptors

A series of 37 benzolactam derivatives were synthesized, and their respective affinities for the dopamine D₂ and D₃ receptors evaluated. The relationships between structures and binding affinities were investigated using both ligand‐based (3D‐QSAR) and receptor‐based methods. The results revealed the importance of diverse structural features in explaining the differences in the observed affinities, such as the location of the benzolactam carbonyl oxygen, or the overall length of the compounds. The optimal values for such ligand properties are slightly different for the D₂ and D₃ receptors, even though the binding sites present a very high degree of homology. We explain these differences by the presence of a hydrogen bond network in the D₂ receptor which is absent in the D₃ receptor and limits the dimensions of the binding pocket, causing residues in helix 7 to become less accessible. The implications of these results for the design of more potent and selective benzolactam derivatives are presented and discussed.     

Continuous and scale‐up synthesis of high purity H2O2 by safe gas‐phase H2/O2 plasma reaction

A new generation of double dielectric barrier discharge (DDBD) reactor featured by a metal powder (MP) high voltage electrode is presented. The MP high voltage electrode not only has excellent homogeneous discharge performance but also has the advantage of without regular maintenance. Therefore, the MP‐DDBD reactor was proved to be suitable for the uninterrupted and safe synthesis of high purity H₂O₂ aqueous solution with up to 65 wt % concentration from the H₂/O₂ mixture. The scale‐up synthesis of H₂O₂ was successfully attempted in an integrated device based on the MP‐DDBD reactor. The future practical H₂O₂ synthesizer based on the MP‐DDBD reactor will be small and movable, and therefore, be convenient to supply high purity H₂O₂ on site for small scale users like semiconductor industry. © 2013 American Institute of Chemical Engineers AIChE J 60: 415–419, 2014     

Enzymatic Synthesis of 1‐Alkyl‐2‐hydroxy‐sn‐glycero‐2,3‐cyclic‐phosphate Using a Novel Lysoplasmalogen‐Specific Phopholipase D

Many phospholipase Ds (PLDs) are known to catalyze transphosphatidylation as well as hydrolysis of phospholipids. Transphosphatidylation of lysoplasmalogen (LyPls)‐specific phospholipase D (LyPls‐PLD), which catalyzes hydrolysis of ether lysophospholipids such as LyPls and 1‐hexadecyl‐2‐hydroxy‐sn‐glycero‐3‐phosphocholine (Lyso‐PAF), still remains unclear. This study aims to reveal the transphosphatidylation activity of LyPls‐PLD, that is, the production of cyclic ether lysophospholipid. The enzymatic reaction is conducted in a buffer system, and the reaction products of a novel LyPls‐PLD from Thermocrispum sp. are investigated using mass spectrometry (MS). MS analyses demonstrate the reaction products to consist of 100% 1‐hexadecyl‐2‐hydroxy‐sn‐glycero‐2,3‐cyclic‐phosphate (cLyPA) and choline from Lyso‐PAF; however, 1‐alkenyl‐2‐hydroxy‐sn‐glycero‐2,3‐cyclic‐phosphate from 1‐O‐1′‐(Z)‐octadecenyl‐2‐hydroxy‐sn‐glycero‐3‐phosphocholine and 1‐O‐1′‐(Z)‐octadecenyl‐2‐hydroxy‐sn‐glycero‐3‐phosphoethanolamine is not produced. These results are expected to help in elucidating the catalytic mechanism of LyPls‐PLD, that is, the rate‐limiting step, and indicate LyPls‐PLD to be useful for the one‐pot synthesis of cLyPA. Practical Applications: A novel phospholipase D, LyPls‐PLD, can exclusively synthesize cLyPA from Lyso‐PAF using a one‐step enzymatic reaction without an organic solvent. cLyPA could be expected to show bioactivities similar to those of cyclic phosphatidic acid, which promotes normal cell differentiation, hyaluronic acid synthesis, antiproliferative activity in fibroblasts, and inhibitory activity toward cancer cell invasion and metastasis.     

Creation of 3D terahertz photonic crystals by the direct writing technique with a TiO2 sol‐gel ink

Three‐dimensional TiO₂ woodpile terahertz photonic crystals with feature size less than 100 μm were created by the direct writing technique with a TiO₂ sol‐gel ink. With proper heat treatment, the rheological properties of the TiO₂ sol‐gel ink were modulated to meet the requirement to construct 3D‐TPCs with feature size less than 100 μm by the direct writing technique. Well‐crystallized rutile TiO₂ 3D‐TPCs were obtained by the calcination process to provide the required high refractive indices, while the lattice periods of these TiO₂ 3D‐TPCs could be changed to tune their terahertz properties. With the increase of the lattice period, a shift of their THz photonic band gap peaks toward the lower frequency was observed in both the simulated and experimental investigations.     

An Engineered Biocatalyst for the Synthesis of Glycoconjugates: Utilization of β1,3‐N‐Acetyl‐D‐glucosaminyltransferase from Streptococcus agalactiae Type Ia Expressed in Escherichia coli as a Fusion with Maltose‐Binding Protein

A fusion protein composed of β1,3‐N‐acetyl‐D ‐glucosaminyltransferase (β1,3‐GlcNAcT) from Streptococcus agalactiae type Ia and maltose‐binding protein (MBP) was produced in Escherichia coli as a soluble and highly active form. Although this fusion protein (MBP‐β1,3‐GlcNAcT) did not show any sugar‐elongation activity to some simple low‐molecular weight acceptor substrates such as galactose, Galβ(1→4)Glc (lactose), Galβ(1→4)GlcNAc (N‐acetyllactosamine), Galβ(1→4)GlcNAcβ(1→3)Galβ(1→4)Glc (lacto‐N‐tetraose), and Galβ(1→4)GlcβCer (lactosylceramide, LacCer), the multivalent glycopolymer having LacCer‐mimic branches (LacCer mimic polymer, LacCer primer) was found to be an excellent acceptor substrate for the introduction of a β‐GlcNAc residue at the O‐3 position of the non‐reducing galactose moiety by this engineered enzyme. Subsequently, the polymer having GlcNAcβ(1→3)Galβ(1→4)Glc was subjected to further enzymatic modifications by using recombinant β1,4‐D ‐galactosyltransferase (β1,4‐GalT), α2,3‐sialyltransferase (α2,3‐SiaT), α1,3‐L ‐fucosyltransferase (α1,3‐FucT), and ceramide glycanase (CGase) to afford a biologically important ganglioside; Neu5Aα(2→3)Galβ(1→4)[Fucα(1→3)]GlcNAcβ(1→3)Galβ(1→4)GlcCerα(IV3Neu5Acα,III3Fucα‐nLc4Cer) in 40% yield (4 steps). Interestingly, it was suggested that MBP‐β1,3‐GlcNAcT could also catalyze a glycosylation reaction of the LacCer mimic polymer with N‐acetyl‐D ‐galactosamine served from UDP‐GalNAc to afford a polymer carrying trisaccharide branches, GalNAcβ(1→3)Galβ(1→4)Glc. The versatility of the MBP‐β1,3‐GlcNAcT in the practical synthesis was preliminarily demonstrated by applying this fusion protein as an immobilized biocatalyst displayed on the amylose resin which is known as a solid support showing potent binding‐affinity with MBP.     

Stereochemical elucidation of complex α‐methyl and β‐methylene carbon resonances in poly(2‐hydroxy ethyl methacrylate‐co‐methacrylonitrile) by 2D NMR

Copolymers of 2‐hydroxy ethyl methacrylate and methacrylonitrile (H/M) of different composition were synthesized by free radical bulk polymerization using azobisisobutyronitrile (AIBN) as an initiator under nitrogen atmosphere. The copolymers composition were calculated from ¹H and quantitative ¹³C{¹H}NMR spectra. The complete spectral assignment of complex and overlapped α‐methyl and β‐methylene carbon regions in ¹³C{¹H} NMR spectrum in term of compositional and configurational sequences of H/M copolymers were done with the help of two‐dimensional heteronuclear single quantum coherence (HSQC) and total correlation spectroscopy (TOCSY). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Unsaturated 2‐oxazoline end capping of liquid crystalline polyester by reactive processing and in a solution

End capping of liquid crystalline poly(ethylene terephthalate‐co‐oxybenzoate) with a bifunctional 2‐oxazoline derivative, 2‐(4‐allyloxyphenyl)‐2‐oxazoline, has been performed in melt under the condition of reactive processing and in a solution. The reaction in melt is very fast and, despite some modifier evaporation, it is completed in 2 min at 230°C. The product is a polyester containing unsaturated end groups bonded via esteramide linkage. The presence of unsaturation was proved by ¹³C‐NMR spectroscopy. An increase in temperature and prolongation of the processing time gives raise to thermal‐induced reactions on the unsaturated end groups, resulting in an increase of the glass transition temperature. Depending on the processing temperature decomposition, propagation and crosslinking occur in different extent and influence polymer properties. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1047–1053, 1999     

Equilibrium and kinetic studies on the extraction of gadolinium(III) from nitrate medium by di‐2‐ethylhexylphosphoric acid in kerosene using a single drop technique

The liquid–liquid extraction of Gd(III) from aqueous nitrate medium was studied using di‐2‐ethylhexylphosphoric acid (HDEHP) in kerosene. On the basis of the slope analysis data, the composition of the extracted species was found to be [Gd A₃(HA)] with the extraction equilibrium constant (K_ex) = (1.48 ± 0.042) × 10^?12 mol dm^?3. The results of the effect of temperature on the value of the equilibrium extraction constant indicated the endothermic character of the extraction system. The kinetics of the forward extraction of Gd³⁺ from nitrate medium by HDEHP in kerosene was investigated using the single drop column technique. The rate of flux (mass transfer per unit area) was found to be proportional to [Gd(III)], [H₂A₂]_(o), [NO₃^?], and [H⁺]^?1 in the liquid drop organic phase. The forward extraction rate constant, k_f, was 2.24 × 10^?3 m s^?1 using the equation: Copyright © 2005 Society of Chemical Industry     

CO2 removal by single and mixed amines in a hollow‐fiber membrane module—investigation of contactor performance

This work investigates CO₂ removal by single and blended amines in a hollow‐fiber membrane contactor (HFMC) under gas‐filled and partially liquid‐filled membrane pores conditions via a two‐scale, nonisothermal, steady‐state model accounting for CO₂ diffusion in gas‐filled pores, CO₂ and amines diffusion/reaction within liquid‐filled pores and CO₂ and amines diffusion/reaction in liquid boundary layer. Model predictions were compared with CO₂ absorption data under various experimental conditions. The model was used to analyze the effects of liquid and gas velocity, CO₂ partial pressure, single (primary, secondary, tertiary, and sterically hindered alkanolamines) and mixed amines solution type, membrane wetting, and cocurrent/countercurrent flow orientation on the HFMC performance. An insignificant difference between the absorption in cocurrent and countercurrent flow was observed in this study. The membrane wetting decreases significantly the performance of hollow‐fiber membrane module. The nonisothermal simulations reveal that the hollow‐fiber membrane module operation can be considered as nearly isothermal. © 2014 American Institute of Chemical Engineers AIChE J, 61: 955–971, 2015     

Saturation‐specific pattern of acquired colour vision deficiency in two clinical populations revealed by the method of triads

Subjective colour spaces were reconstructed for persons occupationally exposed to mercury (Hg) and patients with diabetes mellitus type 2, two groups at risk for acquired colour‐vision deficiency, and compared with healthy normal trichromats. Judgments of colour dissimilarity were collected with the method of triads, applied to a composite assortment of colour samples. These were drawn from two widely used colour arrangement tests—10 hues from the Farnsworth D‐15 test and five from the Lanthony Desaturated D‐15d test, ensuring that the assortment sampled two levels of lightness and saturation. The data were analyzed with maximum‐likelihood multidimensional scaling (MDS) and within a novel individual‐differences MDS model to estimate subject‐specific parameters. The MDS solutions for the two clinical groups showed a compression along a blue‐yellow axis, limited however to desaturated hues. This result was confirmed by the individual‐differences model. In addition, the clinical groups were found to place significantly higher weights on the lightness differences between stimuli, conceivably to compensate for their reduced chromatic discrimination. The specific form of colour‐space distortion in the clinical groups indicated an increase in their thresholds for blue‐yellow signals, providing insights into the nature of impairment mechanisms. The results have implications for stimuli and diagnostic procedures for testing individual differences in color vision, and for analyzing the responses. This approach is sensitive to distinctive patterns of subtle colour‐vision impairment underestimated by the conventional D‐15d test. © 2013 Wiley Periodicals, Inc. Col Res Appl, 39, 125–135, 2014     

Investigation of CO2 removal by immobilized carbonic anhydrase enzyme in a hollow‐fiber membrane bioreactor

Gas–liquid membrane contactors are compelling candidate bioreactors for implementing CO₂ capture because of large mass transfer rates and liquid–solid interfaces, low pressure drop, low axial dispersion and mixing, modularity, simple scale‐up or scale‐down, and operational suppleness. Binding the carbonic anhydrase (CA) enzyme on the membrane surface adds extra advantages due to the impressive large hydration turnover number and offers an attractive way for CO₂ capture. This novel approach to CO₂ removal by immobilized CA in a hollow‐fiber membrane bioreactor (HFMB) was investigated via a multiscale steady‐state model, under gas‐filled and partially liquid‐filled membrane pores conditions. The impact of CA loading, buffer acid‐base constant and concentration, membrane wetting, uncatalyzed/catalyzed CO₂ hydration in the wetted membrane zone, operating conditions, and cocurrent/countercurrent flow orientation on the HFMB performance was analyzed. The results showed that this low‐cost, green, and environmentally friendly technology could be an appealing alternative to CO₂ capture from stationary emissions sources. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2996–3007, 2017     

Immobilization of a functionalized poly(ethylene glycol) onto β‐cyclodextrin‐coated surfaces by formation of inclusion complexes: Application to the coupling of proteins

The aim of this study was the immobilization of COOH‐modified poly(ethylene glycol) (PEG) layers onto β‐cyclodextrin‐coated surfaces by formation of inclusion complexes, in view of biosensors applications. To this end, PEGs with one phenyladamantyl and one carboxylic end group (Ad‐PEG‐COOH) were prepared according to a three‐step procedure. After modification of PEG with 4‐toluenesulfonylchloride, the reaction of the tosyl intermediate with the alcoholate of 4‐(1‐adamantyl)‐phenol was carried out in tetrahydrofuran to avoid the formation of by‐products. Then, it was shown by high performance liquid chromatography that the association between β‐cyclodextrin cavities and Ad‐PEG‐COOH polymers was not hindered by the presence of the COOH group. Last, the Ad‐PEG‐COOH polymer was immobilized onto β‐cyclodextrin‐coated gold surfaces by formation of inclusion complexes. The immobilization was performed in water, at room temperature, with a rapid kinetics. After activation of COOH groups with N‐hydroxysuccinimide, β‐lactoglobulin was coupled to the biocompatible PEG layer. Functionalization of the gold surface with β‐cyclodextrin cavities, immobilization of Ad‐PEG‐COOH onto the surface, and coupling of the protein to the reactive PEG layer were followed in real time by surface plasmon resonance imaging system. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2362–2370, 2006     

Kinetics,degradation pathway and reaction mechanism of advanced oxidation of 4‐nitrophenol in water by a UV/H2O2 process

Photooxidation of 4‐nitrophenol (4‐NP) in water by the UV/H₂O₂ advanced oxidation process was carried out in order to investigate the kinetics and pathway of 4‐NP degradation. The experimental results showed that the photodegradation of 4‐NP accorded well with pseudo‐first order kinetics. The effects of different parameters, such as H₂O₂ dosage, pH value and various anion scavengers on the degradation of 4‐NP have been investigated in detail. It was found that acidic conditions are more favorable to the degradation of 4‐NP but many anions, such as HCO₃^?, NO₃^? and Cl^?, slow down the photooxidation rate of 4‐NP. Hydroquinone, 1,2,4‐trihdroxybenzene, 4‐nitropyrogallol, and 4‐nitrocatechol were tentatively identified as the intermediates of 4‐NP degradation by GC/MS after samples were derivatized by N,O‐bis(trimethylsilyl)‐trifluoroacetamide (BSTFA). A degradation pathway was proposed to account for the observed intermediates produced during 4‐NP degradation by the UV/H₂O₂ process. Copyright © 2003 Society of Chemical Industry