Quantification of glucose diffusion in human lung tissues by using Fourier domain optical coherence tomography

In this study, we report permeability coefficients of 30% glucose diffusion by the optical coherence tomography signal slope (OCTSS) method in four kinds of human lung tissue in vitro: normal lung tissue, benign granulomatosis lung tissue, squamous cell carcinoma and adenocarcinoma tumor. To quantify the permeability coefficient of the agent, the monitored region was 80 μm thickness at a tissue depth of ca 230 μm from the surface. The permeability coefficients of 30% glucose from 10 independent experiments were averaged and found to be (1.35 ± 0.13) × 10(-5) cm s(-1) from the normal lung tissue, (1.78 ± 0.21) × 10(-5) cm s(-1) from the benign granulomatosis lung tissue, (2.88 ± 0.19) × 10(-5) cm s(-1) from the adenocarcinoma tumor and (3.53 ± 0.25) × 10(-5) cm s(-1) from the squamous cell carcinoma, respectively. It could be clearly seen that the permeability coefficients of 30% glucose increase ca 32%, 113% and 162% in the benign granulomatosis, adenocarcinoma tumor and squamous cell carcinoma of human lung tissue compared with that from the normal lung tissue, respectively. Therefore, we inferred from this pilot study that the OCT imaging is a feasible method to distinguish normal and cancer lung tissue.     

Synergistic Effect of Ultrasound and Thiazone–PEG 400 on Human Skin Optical Clearing In Vivo

In this paper, we propose a new physical method in combination with mixed solution of thiazone and polyethylene glycol 400 (thiazone PEG 400 solution) penetration into tissue to assess the skin optical clearing. Four treatments were performed: (1) control group (C); (2) polyethylene glycol 400 (PEG400); (3) 0.25% thiazone (0.25%T); (4) 0.25% thiazone and 5-min ultrasound (0.25%T/SP). The diffuse reflectance spectra and imaging depth of human skin in vivo at different times were measured by spectroscopy and optical coherence tomography (OCT). The optical clearing efficacy of skin was qualitatively and quantitatively analyzed. The results showed that the diffuse reflectance at 540 nm of samples at 10 min after being treated by 0.25%T/SP decreased by approximately 15.51%, whereas, 0.46%, 4.73% and 5.75% were received in C, PEG400 and 0.25%T, respectively. And at 60 min, the decrease in diffuse reflectance of samples in 0.25%T/SP is about 2.22-fold, 1.20-fold compared with that of the samples in PEG 400 and 0.25%T, at 540 nm, respectively. Simultaneously, 0.25%T/SP results in 41.33% increase in OCT 1/e light penetration depth after 60 min. There was a significant difference in the optical clearing effect on skin between ultrasound-mixed solution of thiazone in combination with PEG 400 and the mixed solution (P < 0.05).     

ESR and optical studies of Cu2+ doped zinc glutamate dihydrate

The ESR study of the Cu2+ doped zinc glutamate dihydrate is carried out at room temperature. Two magnetically nonequivalent sites for Cu2+ are observed. The spin Hamiltonian parameters are determined with the fitting of spectra to rhombic symmetry crystalline field. The parameters are as follows: Cu2+(I): gx=2.0170±0.0002, gy=2.0768±0.0002, gz=2.2334±0.0002, Ax=(74±2)×10(-4), Ay=(99±2)×10(-4), Az=(134±2)×10(-4) cm(-1)and Cu2+(II): gx=2.0180±0.0002, gy=2.0550±0.0002, gz=2.1633±0.0002, Ax=(100±2)×10(-4), Ay=(100±2)×10(-4), Az=(115±2)×10(-4) cm(-1). The ground state wave function is also determined. The g-anisotropy is evaluated and compared with the experimental value. Using the data of optical absorption study undertaken at room temperature the nature of bonding in the complex is also discussed.     

Changes in the optical properties of benzo[a]pyrene-coated aerosols upon heterogeneous reactions with NO2 and NO3

Chemical reactions can alter the chemical, physical, and optical properties of aerosols. It has been postulated that nitration of aerosols can account for atmospheric absorbance over urban areas. To study this potentially important process, the change in optical properties of laboratory-generated benzo[a]pyrene (BaP)-coated aerosols following exposure to NO(2) and NO(3) was investigated at 355 nm and 532 nm by three aerosol analysis techniques. The extinction coefficient was determined at 355 nm and 532 nm from cavity ring-down aerosol spectroscopy (CRD-AS); the absorption coefficient was measured by photoacoustic spectroscopy (PAS) at 532 nm, while an on-line aerosol mass spectrometer (AMS) supplied real-time quantitative information about the chemical composition of aerosols. In this study, 240 nm polystyrene latex (PSL) spheres were thinly coated with BaP to form 300 or 310 nm aerosols that were exposed to high concentrations of NO(2) and NO(3) and measured with CRD-AS, PAS, and the AMS. The extinction efficiencies (Q(ext)) changed after exposure to NO(2) and NO(3) at both wavelengths. Prior to reaction, Q(ext) for the 355 nm and 532 nm wavelengths were 4.36 ± 0.04 and 2.39 ± 0.05, respectively, and Q(ext) increased to 5.26 ± 0.04 and 2.79 ± 0.05 after exposure. The absorption cross-section at 532 nm, determined with PAS, reached σ(abs) = (0.039 ± 0.001) × 10(-8) cm(2), indicating that absorption increased with formation of nitro-BaP, the main reaction product detected by the AMS. The single-scattering albedo (SSA), a measure of particle scattering efficiency, decreased from 1 to 0.85 ± 0.03, showing that changes in the optical properties of BaP-covered aerosols due to nitration may have implications for regional radiation budget and, hence, climate.     

Morphological changes in blood vessels produced by hyperosmotic agents and measured by optical coherence tomography

Optical tissue clearing by hyperosmotic chemical agents significantly increases light depth penetration in skin and may improve light-based therapeutics such as laser treatment of cutaneous vascular lesions. A feasibility study was conducted to evaluate the potential role of optical clearing by glycerol in laser treatment of cutaneous vessels. Optical imaging was performed to investigate the morphological effects of glycerol on blood vessels of skin. Blood vessels were imaged using Doppler optical coherence tomography in in vivo hamster skin treated with glycerol. Images were obtained from the subdermal side to assess morphological changes in the blood vessels caused by glycerol and from the epidermal side to assess enhanced Doppler imaging of blood vessels. Application of glycerol to the subdermis resulted in venule stasis and for prolonged treatment times, arteriole stasis. In cases where flow remained in arterioles, an improved Doppler signal was detected from blood vessels when imaging transepidermally compared with the native condition. Intensity images indicated changes in blood optical properties and improved contrast of skin cross sections after glycerol application. The observed optical and morphological effects were reversed upon hydration of the skin with phosphate-buffered saline. The combination of increased depth of light penetration and the temporary slowing or cessation of flow in blood vessels could mean improved laser treatment of vessels.     

Enhanced transdermal delivery of zidovudine in rats and human skin

Zidovudine (azidothymidine, AZT), a potent antiviral agent acting on acquired immunodeficiency syndrome virus, was examined with regard to permeation through rat and human skin. A steady state plasma concentration of AZT after transdermal application in rats estimated from both pharmacokinetics data after i.v. administration and penetration rate through excised rat skin from 10% oleic acid (OA) aqueous solution shows penetration about 85 times higher compared to that from 10% OA would be needed for therapeutic efficacy. A mixed-solvent system consisted of 5% Sefsol-318 (S-318), 10% OA, 10% N-methyl-2-pyrrolidone (MP), 20% propylene glycol (PG) and water showed promising characteristics as a vehicle in terms of permeability of AZT through excised rat skin. The maximum flux of 0.41 mumol/cm2/h was observed in excised human skin after application of a gel formulation including S-318, OA, MP and PG. The result suggests a possible use of the gel formulation to gain an effective plasma concentration in humans.     

Release of nortriptyline hydrochloride from oil-water microemulsions

The release of nortritptyline hydrochloride from oil-in-water (o/w) microemulsions (isopropyl myristate as oil, propylene glycol as cosurfactant, polysorbate 80 as surfactant and phosphate buffer, pH 7.4, as the continuous phase) containing increasing concentrations of polyethylene glycol 400, used to facilitate the diffusion of a drug from the inner oily phase of the microemulsion to the outer aqueous phase of such a dispersion system, was studied by determining the permeability constants of the drug through hydrophilic and lipophilic membranes separating the o/w microemulsions from the receiving aqueous phase (phosphate buffer pH 7.4). The permeability of nortriptyline hydrochloride from microemulsions through the lipophilic membrane increased as the concentration of polyethylene glycol 400 in the disperse system increased. The apparent permeability constant for nortriptyline hydrochloride, from the microemulsion without polyethylene glycol, was 1.36 x 10(-3) cm x h(-1), it increased up to 7.80 x 10(-3) cm x h(-1) in the presence of polyethylene glycol at a concentration of 50% (v/v) of the initial volume of the aqueous phase.     

Effect of pharmaceutically acceptable glycols on the stability of the liquid crystalline gels formed by Poloxamer 407 in water

The ability of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) block copolymers (Poloxamers) to form "gels" (lyotropic liquid crystalline structures) in water is of interest to pharmaceutical applications. In such applications the presence of polar organic solvents is often desirable or required. The effect of such solvents on the stability of lyotropic liquid crystalline gels formed by PEO-PPO-PEO block copolymers was assessed by studying the phase behavior and structure in ternary isothermal (25 degrees C) systems of pharmaceutical interest consisting of Poloxamer 407 (EO(100)PO(70)EO(100)), water, and one of the following solvents (referred to here collectively as "glycols"): glycerol, propylene glycol, ethanol, polyethylene glycol 400, and glucose. Small-angle X-ray scattering was employed to establish the structure of the liquid crystals obtained and to determine their characteristic length scales. The stability range of the liquid crystalline gel phases in the systems studied was found to vary with the glycol type. For example, the micellar cubic structure can accommodate about 0.85:1 parts glucose per part water (in terms of weight) and up to as much as 5.5:1 parts propylene glycol per part water. A correlation between the glycol effects on the stability of the liquid crystalline phases and glycol physiochemical characteristics such as octanol/water partition coefficient or solubility parameter is proposed.     

Kinetic detection of the end-point in titrations involving slow reactions Direct titration of polyhydroxy-compounds with periodate

A new titration technique is described in which the end-point is determined by measuring the relative reaction rate of the titration reaction. This technique is adequate for rather slow reactions where conventional direct titrations are not applicable. The titrations are done automatically under microcomputer control. The efficiency of this technique is demonstrated with direct titrations of certain polyhydroxy-compounds with standard periodate solution. Ethylene glycol and propylene glycol (0.05-0.3 mmole), glycerol (0.06-0.17 mmole) and mannitol (0.01-0.03 mmole) were determined with average relative errors of 0.1-0.3%.     

Study on the Deactivation Kinetics of Pd（PPh3）2Cl2 in the Monocarbonylation of Benzyl Chloride

The deactivation kinetics of Pd(PPh3)2Cl2 in the monocarbonylation of benzyl chloride to synthesize phenylacetic acid is studied in this paper. Solid 1-(2-pyridylazo)-2-naphthol (PAN) is used as the colouring agent, and the concentration of Pd(PPh3)2Cl2 in the system is measured through absorptiometry. The result shows that the optimum condition of the chromogenic reaction between Pd2+ and PAN is: 0.5 ml of 0.04% PAN added to 10 ml of Pd2+ solution (1.0×10-6-2.0×10-5 mol/L), and heated in a constant temperature water bath at 40℃ for about 30 min, with pH of the solution being about 3.0. The molar coefficient of absorption is 1.384×104 L/(mol·cm); the orders of the hydrolytic reaction to the concentration of Pd(PPh3)2Cl2, PPh3, phenylacetic acid and NaOH are 0.5, minus 0.8, 2 and 1.2, respectively. The activation energy (E) of the hydrolytic reaction is 75.59 kJ/mol, and the pre-exponential factor is 1.68×1012.     

In vitro percutaneous absorption of thiamine disulfide through rat skin from a mixture of propylene glycol and fatty acid or its analog.

Percutaneous absorption of thiamine disulfide, (TDS), a lipophilic derivative of thiamine, from a mixture of propylene glycol (PG) and fatty acid (FA) or its analog through rat skin was tested in vitro. Lauric acid (12:0) enhanced the absorption depending on its concentration in PG and showed a maximal enhancement at 10% w/w. At 10% w/v, lauryl alcohol also enhanced the absorption, but less than 12:0, which lauric acid methyl ester suppressed the absorption. The flux of TDS did not depend on the solubility of TDS in the vehicle, but on the permeability coefficient. From these results, it is suggested that FA increases the permeability coefficient not only because FA increases TDS diffusion by disrupting lipid packing in the stratum corneum but also, FA increases TDS partition to lipid phase by interacting with TDS.     

Enhanced percutaneous penetration of flufenamic acid using lipid disperse systems containing glycosylceramides

The usefulness of lipid disperse systems, containing soybean phosphatidylcholine (PC) and glycosylceramide (GC) as lipid components, to enhance the percutaneous penetration of flufenamic acid (FA) through rat abdominal skin was examined by both in vitro permeation and in vivo absorption studies. The penetration of FA from a simple buffer suspension (pH 3.0) containing no lipid component was poor, but was markedly enhanced when FA was incorporated in PC-dispersions. However, this enhancing effect disappeared when the PC concentration in the preparation exceeded 40 mumol/ml. Enhanced penetration of FA from PC-dispersions could also be recognized when 30% propylene glycol or 30% glycerol was used as the dispersing medium instead of the aqueous buffer solution. Addition of GC to the PC-dispersions brought further enhancement of FA penetration through the skin. The maximal effect was observed when FA was incorporated in a 10%-GC system, and the cumulative amount of FA penetrating through the skin in 24 h from this system was approximately 6-fold larger than that from the simple buffer suspension. Enhanced absorption of FA from lipid disperse systems was also confirmed by in vivo application of these preparations.     

Reaction of hydroxyl radicals with C4H5N (pyrrole): temperature and pressure dependent rate coefficients

Absolute (pulsed laser photolysis, 4-639 Torr N(2) or air, 240-357 K) and relative rate methods (50 and 760 Torr air, 296 K) were used to measure rate coefficients k(1) for the title reaction, OH + C(4)H(5)N → products (R1). Although the pressure and temperature dependent rate coefficient is adequately represented by a falloff parametrization, calculations of the potential energy surface indicate a complex reaction system with multiple reaction paths (addition only) in the falloff regime. At 298 K and 760 Torr (1 Torr = 1.33 mbar) the rate coefficient obtained from the parametrization is k(1) = (1.28 ± 0.1) × 10(-10) cm(3) molecule(-1) s(-1), in good agreement with the value of (1.10 ± 0.27) × 10(-10) cm(3) molecule(-1) s(-1) obtained in the relative rate study (relative to C(5)H(8), isoprene) at this temperature and pressure. The accuracy of the absolute rate coefficient determination was enhanced by online optical absorption measurements of the C(4)H(5)N concentration at 184.95 nm using a value σ(184.95nm) = (1.26 ± 0.02) × 10(-17) cm(2) molecule(-1), which was determined in this work.     

Reactive uptake of HONO to TiO2 surface: "dark" reaction

The interaction of HONO with TiO(2) solid films was studied under dark conditions using a low pressure flow reactor (1-10 Torr) combined with a modulated molecular beam mass spectrometer for monitoring of the gaseous species involved. The reactive uptake of HONO to TiO(2) was studied as a function of HONO concentration ([HONO)(0) = (0.3-3.3) × 10(12) molecules cm(-3)), water concentration (RH = 3 × 10(-4) to 13%), and temperature (T = 275-320 K). TiO(2) surface deactivation upon exposure to HONO was observed. The measured initial uptake coefficient of HONO on TiO(2) surface was independent of the HONO concentration and showed slight negative temperature dependence (activation factor = -1405 ± 110 K). In contrast, the relative humidity (RH) was found to have a strong impact on the uptake coefficient: γ(0) = 1.8 × 10(-5) (RH)(-0.63) (calculated using BET surface area, 40% uncertainty) at T = 300 K. NO(2) and NO were observed as products of the HONO reaction with TiO(2) surface with sum of their yields corresponding to nearly 100% of the nitrogen mass balance. The yields of the NO and NO(2) products were found to be 42 ± 7% and 60 ± 9%, respectively, independent of relative humidity, temperature, and concentration of HONO under experimental conditions used. The contribution of aerosol to the total HONO loss in the boundary layer (calculated with initial uptake data for HONO on TiO(2) surface) showed the unimportance of this process in the atmosphere. In addition, the diffusion coefficient of HONO in He was determined to be D(HONO-He) = 490 ± 50 Torr cm(2) s(-1) at T = 300 K.     

Enhancing effect of cetyl lactate on the percutaneous absorption of indomethacin in rats

The enhancing effect of cetyl lactate (CL) on the percutaneous absorption of indomethacin (ID) from test solutions in propylene glycol (PG) was investigated by using the abdominal skin of rats in vivo. The percutaneous absorption rate of ID from 1 or 3% CL-PG test solution through the intact skin of rats was observed to be faster than that from the control solution (without CL). The bioavailability of ID was about 0.04% for the control solution, 2.2% for 1% CL-PG and 6.8% for 3% CL-PG test solutions. These results suggest that CL functions as an enhancer for the percutaneous absorption of ID. Furthermore, marked enhancing effects on percutaneous absorption of ID were obtained at a concentration greater than 1% CL in PG. In order to elucidate the mode of action of CL as an absorption enhancer, the percutaneous absorption of ID from the control solution and 3% CL-PG test solution through damaged skin from which the stratum corneum had been stripped was additionally investigated. It was confirmed that CL acts on the stratum corneum to produce its effect.     

Trace species detection in the near infrared using Fourier transform broadband cavity enhanced absorption spectroscopy: initial studies on potential breath analytes

Cavity enhanced absorption measurements have been made of several species that absorb light between 1.5 and 1.7 μm using both a supercontinuum source and superluminescent light emitting diodes. A system based upon an optical enhancement cavity of relatively high finesse, consisting of mirrors of reflectivity ～99.98%, and a Fourier transform spectrometer, is demonstrated. Spectra are recorded of isoprene, butadiene, acetone and methane, highlighting problems with spectral interference and unambiguous concentration determinations. Initial results are presented of acetone within a breath-like matrix indicating ppm precision at <～10 ppm acetone levels. Instrument sensitivities are sufficiently enhanced to enable the detection of atmospheric levels of methane. Higher detection sensitivities are achieved using the supercontinuum source, with a minimum detectable absorption coefficient of ～4 × 10(-9) cm(-1) reported within a 4 min acquisition time. Finally, two superluminescent light emitting diodes are coupled together to increase the wavelength coverage, and measurements are made simultaneously on acetylene, CO(2), and butadiene. The absorption cross-sections for acetone and isoprene have been measured with an instrumental resolution of 4 cm(-1) and are found to be 1.3 ± 0.1 × 10(-21) cm(2) at a wavelength of 1671.9 nm and 3.6 ± 0.2 × 10(-21) cm(2) at 1624.7 nm, respectively.     

Collisional relaxation of O2(X3Σg(-), υ = 1) and O2(a1Δg, υ = 1) by atmospherically relevant species

Laboratory measurements are reported of the rate coefficient for collisional removal of O(2)(X(3)Σ(g)(-), υ = 1) by O((3)P), and the rate coefficients for removal of O(2)(a(1)Δ(g), υ = 1) by O(2), CO(2), and O((3)P). A two-laser method is employed, in which the pulsed output of the first laser at 285 nm photolyzes ozone to produce oxygen atoms and O(2)(a(1)Δ(g), υ = 1), and the output of the second laser detects O(2)(a(1)Δ(g), υ = 1) via resonance-enhanced multiphoton ionization. The kinetics of O(2)(X(3)Σ(g)(-), υ = 1) + O((3)P) relaxation is inferred from the temporal evolution of O(2)(a(1)Δ(g), υ = 1), an approach enabled by the rapid collision-induced equilibration of the O(2)(X(3)Σ(g)(-), υ = 1) and O(2)(a(1)Δ(g), υ = 1) populations in the system. The measured O(2)(X(3)Σ(g)(-), υ = 1) + O((3)P) rate coefficient is (2.9 ± 0.6) × 10(-12) cm(3) s(-1) at 295 K and (3.4 ± 0.6) × 10(-12) cm(3) s(-1) at 240 K. These values are consistent with the previously reported result of (3.2 ± 1.0) × 10(-12) cm(3) s(-1), which was obtained at 315 K using a different experimental approach [K. S. Kalogerakis, R. A. Copeland, and T. G. Slanger, J. Chem. Phys. 123, 194303 (2005)]. For removal of O(2)(a(1)Δ(g), υ = 1) by O((3)P), the upper limits for the rate coefficient are 4 × 10(-13) cm(3) s(-1) at 295 K and 6 × 10(-13) cm(3) s(-1) at 240 K. The rate coefficient for removal of O(2)(a(1)Δ(g), υ = 1) by O(2) is (5.6 ± 0.6) × 10(-11) cm(3) s(-1) at 295 K and (5.9 ± 0.5) × 10(-11) cm(3) s(-1) at 240 K. The O(2)(a(1)Δ(g), υ = 1) + CO(2) rate coefficient is (1.5 ± 0.2) × 10(-14) cm(3) s(-1) at 295 K and (1.2 ± 0.1) × 10(-14) cm(3) s(-1) at 240 K. The implications of the measured rate coefficients for modeling of atmospheric emissions are discussed.     

由聚丙二醇二缩水甘油醚和甘油制备温敏性超支化聚合物

由聚丙二醇二缩水甘油醚和甘油通过质子转移聚合(proton transfer polymerization)一步法制备了端羟基的温敏性超支化聚醚.聚合产物的分子量(Mn)在1.76×104~2.43×104之间,玻璃化转变温度(Tg)在-31.5~-26.7℃之间,热分解温度(Td)在367~376℃之间.通过控制聚丙二醇二缩水甘油醚和甘油的投料比,实现了对温敏性超支化聚醚最低临界溶解温度(LCST)的调节,LCST可控制在28.3~39.6℃之间.     

罗丹明标记的磷脂分子在亲水表面的单个分子行为

单个分子实验有很重要的意义,一方面，对于非均相体系，单个分子实验可得到分子性质分布信息；另一方面，对于均相和非均相体系，单个分子轨迹直接记录了分子性质的涨落，包含了丰富的动力学信息.在诸多单个分子检测技术中，单分子光学检测技术具有快速、无损、可探测到凝聚相内部单个分子的能力.进行单分子检测的关键是消除拉曼和瑞利散射以及杂质荧光等背景的干扰，利用共焦、近场和隐失场激发减少激发体积和检测体积，可以降低背底，提高信噪比.本实验利用共焦荧光显微镜观测单个罗丹明标记的磷脂分子在亲水玻璃表面的扩散、脱附，及其荧光闪烁的行为.实验表明，除由表面的平均力场阻碍分子运动外，还有一些特殊位点会造成长时间的特异性吸附，并得到特异性吸附的分子的脱附速率，（5.9±0.2）s－1.用穿越时间分布函数测得分子在表面的扩散速率为(3.3±0.1)×10－8 cm2•s－1，与分子在磷脂膜中的扩散速率相当.观测到了一些吸附的分子出现了荧光闪烁的现象，并对其产生原因进行了一些分析.     

基于杂多类离子液体催化体系的甘油氢解反应研究

将一系列不同结构的离子液体与雷尼镍复合,作为甘油氢解制备丙二醇反应的催化剂。考察了离子液体结构对催化性能的影响,优选出具有适宜酸强度的固态磷钨酸质子化咪唑([HMIM]3PW12O40),采用FT-IR、1H-NMR及TG对其进行了表征。[HMIM]3PW12O40/雷尼镍复合催化剂在用量[HMIM]3PW12O400.2 mmol、雷尼镍0.3 g的条件下,催化20 g 40%甘油水溶液在6 MPa氢压(氢醇比为2.37∶1)下,230℃反应11 h,可得到甘油转化率83.3%,氢解产物1,2-丙二醇选择性57.3%的结果,催化剂具有良好的稳定性。