A photochromic salicylaldehyde hydrazone derivative based on C[dbnd]N isomerization and ESIPT mechanisms and its detection of Al3+ in aqueous solution

Optical absorption coefficients of vanadium pentoxide single crystals

To the Editor: Three cases of carbon dioxide rebreathing without a significant color change in the appearance of the canisters were experienced during general anesthesia with the same model anesthesia machines; Aestiva/5 (Datex Ohmeda, Wisconsin, USA) with a fresh gas flow of 1–2 l/min. Carbon dioxide rebreathing was recognized because the inspiratory carbon dioxide baseline of the capnogram trace gradually rose. The inhalational carbon dioxide concentration decreased immediately after increasing the fresh gas flow, and rose again with decreasing the fresh gas flow. This indicates that carbon dioxide rebreathing was due to carbon dioxide accumulation in the semi-closed circuit system of the anesthesia machines. A color change in the appearance of the carbon dioxide absorbent was recognized only in the upper part of the canister (Fig. 1a). The top surface of the canister showed a significant color change limited to the middle part of it (Fig. 1b). The section image of the canister showed a significant columnar color change of the carbon dioxide absorbent along the full length of the center part of it (Fig. 1c). The observation of the canister bottom of Aestiva/5 revealed that only the center part of it had the mesh part for the exhaled gas, and the color change of the carbon dioxide absorbent seemed to accord with the mesh part of the bottom (Fig. 1d). As an experiment, when a transparent plastic partition wall was settled in the canister before filling with carbon dioxide absorbent, the columnar color change was no longer visible. This indicated that the flow of the exhaled gas was influenced by the wall in the canister. Considering these results, it is supposed that the structural characteristic of the canister bottom of the anesthesia machine; Aestiva/5, caused channeling and the inhomogeneity of the current of inhaled gas in the canister led to the columnar color change of the carbon dioxide absorbent. The role of the carbon dioxide absorbent canister becomes more important as the fresh gas flow quantity decreases. A technique of using a fresh gas flow of 1 l/min was reported first in 1952 [1]. The technique with the fresh gas flow less than 1 l/min subsequently became known as ‘‘low-flow anesthesia’’. Afterwards, a technique using a fresh gas flow of 500 ml/min was reported as ‘‘minimal flow anesthesia’’ [2]. These cases of carbon dioxide rebreathing without significant color change in the appearance of the canisters provide very important information not only for anesthesiologists, but also for all persons using anesthesia machines. When carbon dioxide rebreathing is recognized, carbon dioxide accumulation in the circuit system of the anesthesia machines should be suspected and exhaustion of the carbon dioxide absorbent should be immediately T. Yamamoto (&) Department of Pediatric Anesthesiology and Critical Care Medicine, Children’s Hospital Asklepios Klinik Sankt Augustin, Arnold-Janssen-Str. 29, 53757 Sankt Augustin, Germany e-mail: yamatomo270@hotmail.com; t.yamamoto@asklepios.com

Synthesis and photophysical characterization of a Schiff base as anion sensor

The mobility of simple ions such as alkali–metal and halide ions at room temperature shows two anomalies. Firstly, there are maxima in mobilities as a function of ion size for both positive and negative ions and, secondly, the maximum for negative ions occurs at a larger ionic radius than the maximum for positive ions. Theoretical treatments of this problem are reviewed and it is concluded that a molecular treatment of the system is needed to understand the results. Computer simulation using the simple point charge model (SPC/E) for water reproduced the observations and is used to discuss the application of theories. In particular, the nature of the first solvation shell is correlated with ion mobility. Simulation reveals a further anomaly, namely that if the charge is removed from a large ion, then it moves more slowly. This is interpreted as the result of formation of a solvent cage around the hydrophobic solute. The changes in local structure resulting from changes in charge and size also affect the solvation thermodynamics. Simulations show that the solvation entropy has a double maximum when viewed as a function of charge. The local minimum near zero charge is interpreted as being due to hydrophobic order, and the maxima as the result of structure breaking. This double maximum in the entropy of solvation is a signature of the hydrophobic cage effect. Comparisons are made between ion mobilities in liquid water at ambient and supercritical conditions.

Bubble electrospinning technology can be used for mass production of nanofibers, it has been widely used in polymer electrospinning such as PVA, PVP and PAN, but there are no reports on the preparation of composite phase-change nanofibers by this method. In this paper, the transparent solution 1(PEG was put into formic acid according to the mass fraction of 60%) was mixed with the transparent solution 2 (PA66 was put into formic acid according to the mass fraction of 15%) according to the mass ratio of 15:85 , 25:75 , 35:65 and 45:55 to prepare four kinds of spinning solutions. And the pure PA66 nanofiber membrane(PNM) and PA66/PEG composite nanofiber membrane(PGCNM) were fabricated by the improved bubble electrospinning device on the basis of bubble electrospinning device invented by He Jihuan etc Also we analyzed their surface microstructure and tested their mechanical properties, thermal properties and molecular structure. The lower the content of PA66, the smaller the adhesion granular matter on the nanofiber surface and the thicker the diameter of the nanofiber, but the surface of the nanofiber is more smooth. The PGNCM appeared double absorption peak at 1515.5 cm−1 and 1642 cm−1 and existed weak absorption peak at 3298 cm−1 ∼ 3302 cm−1. The tensile strength and the elongation at break of the PGNCM was less than that of the PNM. The hot decomposition process of the PGNCM was composed the melting exothermic process of PEG and PA66. When the mixed ratio between PA66 and PEG was 15:85, the decomposition rate of residues between 210 ∼ 310 °C was the fastest.

The original AO HRR color vision test has been considered by many as one of the best plate tests. It is still accepted by many governmental agencies for color vision certification. In their 1954 publication, Hardy, Rand, and Rittler stated that specially compounded inks were used for printing to avoid color changes with time. Fifty years later, it is both important and interesting to determine whether the wear and tear cause significant color changes. The chance finding of a never-used second edition offers an opportunity to evaluate the color changes. A GretagMacbeth Spectrolino spectrophotometer was used to measure the chromaticities of the never-used book, and an extensively used book. Four plates (#4, 7, 13, 16), selected randomly from the four red-green sections, were analyzed. The colored dots from each of the eight plates were plotted on a CIE chromaticity diagram. Isocolor lines were drawn to evaluate chromatic alignment. Chromaticities for plates #4 and 7 are significantly different between the two books. With regard to alignment with isocolor lines, the extensively used book is better than the never-used book for plate #4. There is significant misalignment on plate #7 for both books. Chromaticities for plates #13 and 16 are essentially identical between books, all with good alignment with isocolor lines. The overall comparison shows that the chromatic alignment characteristics of the extensively used book are not worse than the never-used book. Since colors in these plates have to be aligned with both the protan and deutan axes, any significant color changes would have disturbed this delicate requirement. The findings of many plates with good alignment, and the lack of differences on plates #13 and 16 between books, suggest that there are no significant color changes over time. Differences between books on plates #4 and 7 were likely the result of the original printing process.

funcionalitzat amb un grup sulfonilazida.En presència d'hidrogen sulfur es produïx la reducció del grup sulfonilazida a sulfonilamida que comporta associat un canvi de color apreciable a simple vista i un augment de la intensitat de fluorescència (Eur.

Desmopressin is a synthetic analogue of the natural antidiuretic hormone arginine vasopressin. Over the years, it has been clinically used to manage nocturnal polyuria in children with enuresis. Various pharmaceutical formulations of desmopressin have been commercialized for this indication-nasal spray, nasal drops, oral tablet and oral lyophilizate. Despite the fact that desmopressin is a frequently prescribed drug in children, its use and posology is based on limited pediatric data. This review provides an overview of the current pediatric pharmacological data related to the different desmopressin formulations, including their pharmacokinetics, pharmacodynamics and adverse events. Regarding the pharmacokinetics, a profound food effect on the oral bioavailability was demonstrated as well as different plasma concentration-time profiles (double absorption peak) of the desmopressin lyophilizate between adults and children. Literature about maturational differences in distribution, metabolism and excretion of desmopressin is rather limited. Regarding the pharmacodynamics, formulation/dose/food effect and predictors of response were evaluated. The lyophilizate is the preferred formulation, but the claimed bioequivalence in adults (200µg tablet and 120µg lyophilizate), could not be readily extrapolated to children. Prescribing the standard flat-dose regimen to the entire pediatric population might be insufficient to attain response to desmopressin treatment, whereby dosing schemes based on age and weight were proposed. Moreover, response to desmopressin is variable, whereby complete-, partial- and non-responders are reported. Different reasons were enumerated that might explain the difference in response rate to desmopressin observed: different pathophysiological mechanisms, bladder capacity and other predictive factors (i.e. breast feeding, familial history, compliance, sex, etc.). Also, the relapse rate of desmopressin treatment was high, rendering it necessary to use a pragmatic approach for the treatment of enuresis, whereby careful consideration of the position of desmopressin within this treatment is required. Regarding the safety of the different desmopressin formulations, the use of desmopressin was generally considered safe, but additional measures should be taken to prevent severe hyponatremia. To conclude the review, to date, major knowledge gaps in pediatric pharmacological aspects of the different desmopressin formulations still remain. Additional information should be collected about the clinical relevance of the double absorption peak, the food effect, the bioequivalence/therapeutic equivalence, the pediatric adapted dosing regimens, the study endpoints and the difference between performing studies at daytime or at nighttime. To fill in these gaps, additional well designed pharmacokinetic and pharmacodynamic studies in children should be performed.

To synthesize photonic films without a chiral dopant, a predesigned multiple photopolymerization process was carried out. The photonic films were prepared by the photopolymerization of a mixture of chiral nematic liquid crystals. After polymerization, the chiral dopant, CB15, was removed and recycled. The imprinted photonic polymer films showed Bragg reflection without the presence of the chiral dopant. Upon the sensing of solvents in aqueous solution, significant color changes and peak shifts were observed by the naked eye and ultraviolet–visible spectroscopy, respectively. A linear calibration curve between the central wavelength of the reflection band of the fabricated imprinting film and the volume ratio of 1,4‐dioxane in water was observed. Furthermore, the sensing of chloroform content in methanol, ethanol, and acetone via the imprinted film were also investigated. The results suggest that the synthesized imprinted photonic films can detect different kinds of mixed solvents. The sensing properties of the photonic films were further improved by copolymerization with a rhodamine‐derived monomer. The synthesized modified photonic films can detect heavy metal ions in aqueous solution. This study reports a novel, recyclable, and easy approach to detect organic solvents and copper ions in aqueous solution.

A novel, facile, and low-cost method was developed for determination of cetyltrimethylammonium (CTA+) cationic surfactant in water samples using diffuse reflectance Fourier transform IR (FTIR) spectroscopy and colorimetry. Cetyltrimethylammonium bromide was chosen as a model compound to demonstrate the optimization of the method for determination of CTA+ in water samples. The absorption peak at 3015.96 cm-1 (for CTA+) was enhanced when gold nanoparticles were used as a chemical sensor in diffuse reflectance FTIR spectroscopy, and this absorption peak was used for determination of CTA+. Alternatively, the color change from wine red (525 nm) to blue (740 nm) and the redshift of the localized surface plasmon resonance band in the visible region were used as a sensing probe for determination of CTA+. A linear calibration curve for determination in water samples was obtained in the range from 10 to 100 ng mL-1 with a limit of detection of 3 ng mL-1 by diffuse reflectance FTIR spectroscopy and in the range from 20 to 400 ng mL-1 with a limit of detection of 7 ng mL-1 by colorimetry. The advantageous features of the methods are their simplicity, rapidity, and sensitivity for the determination of CTA+ in water samples. Graphical abstract.

Detection of heavy metal ions in water is of paramount significance for environmental pollution control. Here, we report the use of γ-polyglutamic acid (γ-PGA)-stabilized gold nanoparticles (γ-PGA-Au NPs) as a probe to sense trivalent chromium (Cr3+) in aqueous solution. In our study, γ-PGA-Au NPs were first formed through one-step sodium borohydride reduction of Au salt in the presence of γ-PGA. The formed γ-PGA-Au NPs with a mean particle size of 4.6 nm show desirable colloidal stability and a significant color change from wine red to gray after exposure to Cr3+ ions, which is visible to the naked eye and easily detected by colorimetric assay using UV-vis spectrometry. The limit of detection of Cr3+ ions is 100 ppb by the naked eye and 0.2 ppb by UV-vis spectroscopy, respectively. We further show that the detection of Cr3+ using γ-PGA-Au NPs has excellent selectivity, and the recovery percentage is higher than 82% for different water samples such as lake water, river water, tap water or mineral water. Our study demonstrates that γ-PGA-Au NPs can be utilized as an efficient probe for colorimetric sensing of Cr3+ ions in a water environment.

Heterogeneous "naked-eye" colorimetric and spectrophotometric cation sensors were prepared by immobilization of an azobenzene-coupled receptor onto mesoporous silica (AR-SiO(2)) or titania nanoparticles (AR-TiO(2)) via sol-gel or hydrolysis reactions. The optical sensing ability of AR-SiO(2) was studied by addition of metal ions such as K(+), Ca(2+), Sr(2+), Co(2+), Cd(2+), Pb(2+), Zn(2+), Fe(3+), Cu(2+) and Hg(2+) ions (all as chlorides) in aqueous solution. Upon the addition of Hg(2+) ion in suspension, the AR-SiO(2) resulted in a color change from yellow to deep red. No significant color changes were observed in the parallel experiments with K(+), Ca(2+), Sr(2+), Co(2+), Cd(2+), Pb(2+), Zn(2+), Fe(3+) or Cu(2+) ion. These findings confirm that the AR-SiO(2) can be useful as chemosensors for selective detection of Hg(2+) ion over a range of metal ions in aqueous solution. Also, the color change of AR-SiO(2) was independent of the presence of anions NO(3)(-), ClO(4)(-), Br(-) and I(-). We also prepared a portable chemosensor kit by coating a 4 microm thick film of AR-TiO(2) onto a glass substrate. We found that this AR-TiO(2) film detects Hg(2+) ion at pH 7.4 with a sensitivity of 28 nM. Finally, we tested the effect of pH on AR-TiO(2) with Hg(2+) ion between pH 1.0 to 11.0. The absorbance and color changes of AR-TiO(2) were almost constant between pH 4 and 11. The results imply that the AR-TiO(2) film is applicable as a portable colorimetric sensor for the detection of Hg(2+) ion in the environmental field.

PurposeTo evaluate the color changes and surface roughness of two different gingiva‐colored prosthetic materials after exposure to conventional and electronic cigarettes.Materials and MethodsA total of 60 disk shaped gingiva‐colored porcelain (GC Initial MC Gum, GC Europe NV, Leuven, Belgium) and indirect composite resin (Gradia Plus Gum Shades Heavy Body, GC Europe NV, Leuven, Belgium) specimens, each measuring 2 × 10 mm, were prepared. The porcelain and indirect composite resin samples were divided into two subgroups (n = 30). The initial color and roughness values of the samples were measured. A special setup was created to simulate cigarette smoking, where the samples were placed inside and exposed to two different types of cigarette smoke. After exposure, the final color and roughness values of the samples were measured again.ResultsAfter conventional cigarette exposure, porcelain specimens showed color changes of ΔE*ab = 7.404, ΔE00 = 7.502, and indirect composite resin specimens ΔE*ab = 9.708, ΔE00 = 19.501, with significant surface roughness increases in both materials (p < 0.05). After electronic cigarette exposure, porcelain specimens had color changes of ΔE*ab = 1.390, ΔE00 = 1.317, and indirect composite resin samples ΔE*ab = 2.523, ΔE00 = 2.454. Surface roughness decreased significantly for porcelain (p < 0.05) but increased for composite resin which was not statistically significant (p > 0.05).ConclusionConventional cigarette exposure resulted in more significant color changes and surface roughness increases in gingiva‐colored materials compared to electronic cigarettes. Indirect composite resins demonstrated lower color stability than porcelains. Patients with gingiva‐colored porcelain and composite resin restorations should be informed about color and surface roughness changes due to smoking.

A multifunctional quinoxaline-based chemosensor for colorimetric detection of Fe3+ and highly selective fluorescence turn-off response of Cu+2 and their practical application

Objective: The aim of this study was to evaluate the color stability of dental enamel exposed to cigarette smoke after orthodontic debonding. Methods: Thirty-two bovine incisors were allocated into control (C1 and C2) and experimental groups (n=8) according to distinct bonding protocols: with adhesive (B1) and without adhesive (B2) and exposure to cigarette smoke. Samples from B1, B2 and C2 were exposed to ten cycles of smoke in a specific and hermetic chamber while the C1 remained stored in artificial saliva. Color analysis was performed with a spectrophotometer according to the L*a*b* system. Intergroup comparisons and effect of time were estimated with ANOVA/Tukey and paired Student t tests, respectively (a=0.05). Results: Statistically significant color changes have not been observed in C1 (L*: -0.69 ± 0.80; a*: 0.36 ± 0.23; b*: 0.17 ± 0.50) and without adhesive (B2) (L*: -3.74 ± 2.85; a*: 0.93 ± 0,73; b*: 1.13 ± 1.16) through the study time (p>0,05). However, the group with adhesive (B1) presented significant color changes in L*:-5.55 ± 2.28, a*: 2.33 ± 0.77 and b*: 3.30 ± 1.37, what means, darker, greener and more yellow, respectively (p<0,05) and the control group that was exposed to the cigarette smoke (C2) presented significant color changes in L*: -1.72 ± 0.28 e b*: 1.82 ± 0.22, what means, darker and more yellow, respectively. Conclusion: Enamel color stability was affected by exposure to cigarette smoke after orthodontic debonding, especially when bonding protocolcomprised the application of primer adhesive.