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1.
Cell Physiol Biochem ; 45(4): 1654-1662, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29486472

RESUMO

BACKGROUND/AIMS: Ovarian cancer is one of the most common malignancies with a high rate of mortality in women. However, current therapies for ovarian cancer treatment are ineffective. Therefore, novel target identification is an urgent requisite. The present study aimed to investigate the role of microRNA-214 (miR-214) in ovarian cancer. METHODS: The expression of miR-214, ß-catenin, cyclin D1, c-myc, and TCF-1 at the transcriptional level was measured by real-time PCR, while that of ß-catenin, Cyclin D1, and c-Myc at the protein level were detected by western blot. Colony formation assay and transwell assay were used to explore the invasion ability of the cancer cells. Cell cycle was measured by flow cytometry. RESULTS: Real-time PCR showed that miR-214 expression in ovarian cancer cell lines was lower than that in the human normal ovarian epithelial cells, IOSE80. Furthermore, the low expression of miR-214 was correlated with high pathological grade. The rate of colony formation and invasion of miR-214 overexpression in SKOV-3 cells were weaker than that in control cells. Moreover, miR-214 overexpression led to the G0/G1 phase arrest. The expression of ß-catenin, Cyclin D1, and c-Myc was suppressed by the overexpression of miR-214. CONCLUSION: These results suggested that miR-214 may serve as a tumor suppressor of ovarian cancer by targeting the ß-catenin pathway.


Assuntos
MicroRNAs/metabolismo , Neoplasias Ovarianas/patologia , beta Catenina/metabolismo , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Ciclina D1/genética , Ciclina D1/metabolismo , Regulação para Baixo , Feminino , Pontos de Checagem da Fase G1 do Ciclo Celular , Humanos , MicroRNAs/genética , Neoplasias Ovarianas/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , Pontos de Checagem da Fase S do Ciclo Celular , Fator 1 de Transcrição de Linfócitos T/genética , Fator 1 de Transcrição de Linfócitos T/metabolismo , Via de Sinalização Wnt , beta Catenina/antagonistas & inibidores , beta Catenina/genética
2.
J Environ Sci (China) ; 62: 154-162, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29289287

RESUMO

Chlorinated paraffins (SCCPs) are widely used worldwide, and they can be released into the environment during their production, transport, usage and disposal, which pose potential risks for human health. In this work, an efficient, reliable and rapid pretreatment method based on matrix solid-phase dispersion (MSPD) was developed for the analysis of short-chain CPs (SCCPs) in human placenta by gas chromatograph-electron capture negative ion low-resolution mass spectrometry (GC-ECNI-LRMS) and gas chromatography-quadrupole time-of-flight mass spectrometry (GC-QTOF-HRMS). The MSPD-relevant parameters including dispersing sorbent, sample-to-sorbent mass ratio, and elution solvent were optimized using the orthogonal test. Silica gel was found to be the optimal dispersing sorbent among the selected matrices. Under the optimal conditions, 44% acidic silica gel can be used as the co-sorbent to remove lipid and eluted by the mixture of hexane and dichloromethane (7:3, V/V). The spiked recoveries of the optimized method were 77.4% and 91.4% for analyzing SCCPs in human placenta by GC-ECNI-LRMS and GC-QTOF-HRMS, and the corresponding relative standard deviations were 10.2% and 5.6%, respectively. The method detection limit for the total SCCPs was 36.8ng/g (dry weight, dw) and 19.2ng/g (dw) as measured by GC-ECNI-LRMS and GC-QTOF-HRMS, respectively. The concentrations of SCCPs in four human placentas were in the range of

Assuntos
Fracionamento Químico/métodos , Poluentes Ambientais/metabolismo , Parafina/metabolismo , Placenta/metabolismo , Poluentes Ambientais/análise , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Limite de Detecção , Parafina/análise , Placenta/química , Gravidez
3.
Soft Matter ; 12(1): 191-9, 2016 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-26456396

RESUMO

In this work, we report self-assembled metallogels formed from a ligand of trimesic amide, N,N',N''-tris(4-pyridyl)trimesic amide (TPTA), induced by Fe(III)/Fe(II) ions. TPTA is difficult to dissolve in water even in the presence of some metal ions such as Cu(2+), Co(2+), Ni(2+), K(+), Na(+) and Mg(2+) under heating, and it exhibits no gelation ability. Interestingly, upon heating TPTA can be dissolved easily in aqueous solution containing Fe(3+)/Fe(2+), and subsequently self-assembled into metallogels after cooling. The metallogels could also be formed in aqueous solutions of mixed metal ions containing Fe(3+)/Fe(2+), indicating that the other metal ions do not affect the formation of Fe(III)-TPTA and Fe(II)-TPTA metallogels. The high selectivity of metallogel formation to Fe(3+)/Fe(2+) may be used for application in the test of Fe(3+)/Fe(2+). The metallogels obtained are characterized by scanning electron microscopy, Fourier transform infrared spectra, nuclear magnetic resonance spectra, rheological measurements and scanning tunneling microscopy. The results indicate that TPTA can self-assemble into fibrous aggregates in Fe(3+)/Fe(2+) aqueous solution through the metal-ligand interactions and intermolecular hydrogen bonding. This kind of metallogel also possesses good mechanical properties and thermoreversibility.


Assuntos
Aminopiridinas/química , Benzamidas/química , Géis/química , Ferro/química , Compostos Organometálicos/química , Amidas/química , Aminopiridinas/síntese química , Benzamidas/síntese química , Ligação de Hidrogênio , Estresse Mecânico , Ácidos Tricarboxílicos/química
4.
Soft Matter ; 11(32): 6386-92, 2015 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-26118365

RESUMO

Currently, the design and construction of an intelligent stimuli-responsive gel system is still a significant challenge. We present here a new gel system from which the formation of heat-set gels, conventional gels and irreversible heat-set gels can be achieved in aromatic solvents. This gel system is based on two-component gelators containing a succinamic acid derivative (SAD) and a primary alkyl amine (R-NH2). With the increase of temperature to 85 °C, a rarely reported reversible heat-set gel (gel formation with the increase of temperature) is afforded. Upon addition of fatty acids into two-component gelators, a conventional gel (gel formation with the decrease of temperature) is formed. When the fatty acid is replaced with dicarboxylic acid, a new heat-set gel is generated, which is irreversible and thermally super-stable. X-ray diffraction analysis reveals that the formation of a reversible heat-set gel relies on electrostatic interactions, hydrogen bonds, and hydrophobic interactions. These two-component gelators show a perfect gel system for the formation of diverse gels including heat-set gels, conventional gels and irreversible heat-set gels. The tunable strategy demonstrated in this letter may provide a new way for creation of more functional gels in gel science.


Assuntos
Aminas/química , Géis/química , Succinatos/química , Ácidos Carboxílicos/química , Ácidos Graxos/química , Ligação de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Eletricidade Estática , Temperatura
5.
Med Int (Lond) ; 4(1): 8, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38283134

RESUMO

The main objective of the present study was to investigate whether forced vital capacity (FVC)%/diffusing capacity of the lungs for carbon monoxide (DLCO)% can be used to predict the presence of pulmonary hypertension (PH) in connective tissue disorders (CTDs). For this purpose, a total of 53 individuals who were diagnosed with CTDs and had undergone right heart catheterization between July, 2019 and July, 2022 were included in the present study. Based on the mean pulmonary artery pressure (mPAP) measured during right heart catheterization, the participants were divided into the PH and non-PH groups. The differences in demographic characteristics, including sex, age, body mass index, smoking index, FVC%/DLCO% and pulmonary artery systolic pressure (PASP) were determined by echocardiography; moreover, the 6-min walk distance, plasma brain natriuretic peptide (BNP) levels, white blood cell count, red blood cell distribution width, erythrocyte sedimentation rate and C-reactive protein levels were compared between the two groups to identify independent predictors of PH. The independent predictors were subsequently evaluated for their correlation with mPAP to assess their predictive value for PH. FVC%/DLCO%, echocardiographic PASP, and plasma BNP levels were identified as independent predictors of PH. FVC%/DLCO% and echocardiographic PASP exhibited a significant correlation with mPAP, while the correlation between plasma BNP and mPAP levels was not statistically significant. The area under the curve (AUC) value for FVC%/DLCO% alone in predicting PH was 0.791, with an optimal diagnostic threshold of 1.35, a sensitivity of 0.794 and a specificity of 0.789. The AUC for echocardiographic PASP alone in predicting PH was 0.783, with an optimal diagnostic threshold of 39.5 mmHg, a sensitivity of 0.794 and a specificity of 0.684. When combined, the AUC of the two factors in predicting PH was 0.872, with a sensitivity of 0.941 and a specificity of 0.684. Collectively, the data of the present study indicate that FVC%/DLCO% may be used as a predictive factor for CTD-PH, and its combined application with echocardiographic PASP measurement may provide additional evidence for the clinical diagnosis of CTD-PH.

6.
Org Lett ; 26(1): 41-45, 2024 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-38149590

RESUMO

The development of an efficient method for the synthesis of C4 oxy-substituted indoles is an appealing yet challenging task. Herein, we report a general palladium-catalyzed TDG approach for the direct C4-H acyloxylation of indoles. The protocol features atom and step economy, excellent regioselectivity, and good tolerance of functional groups. Moreover, the reaction can accommodate a range of carboxylic acids including benzoic acids, phenylacetic acids, and aliphatic acids.

7.
J Am Chem Soc ; 135(32): 11684-7, 2013 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-23885835

RESUMO

An extremely stable hydrogen-bonded organic framework, HOF-8, was fabricated. HOF-8 is not only thermally stable but also stable in water and common organic solvents. More interestingly, desolvated HOF-8 exhibits high CO2 adsorption as well as highly selective CO2 and C6H6 adsorption at ambient temperature.


Assuntos
Benzamidas/química , Benzeno/isolamento & purificação , Dióxido de Carbono/isolamento & purificação , Adsorção , Gases/isolamento & purificação , Ligação de Hidrogênio , Modelos Moleculares , Porosidade
8.
Langmuir ; 29(47): 14411-20, 2013 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-24156383

RESUMO

The monolayer structures and conformational ordering of cationic surfactants including the biodegradable quaternary ammonium molecules have been systematically characterized by π-A isotherm, surface potential, atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and sum frequency generation (SFG) vibrational spectroscopy. It was found that the monolayer of the typical dialkyl dimethylammonium on the water surface was less densely packed along with many conformational gauche defects. The packing density and ordering of these monolayers were improved as halide ions were added to the subphase. A similar condensation effect was also observed when amide or ester groups are present in the alkyl tails of the surfactant. These results are discussed on the basis of the repulsive electrostatic interactions between the terminal ammonium moieties, the hydrogen bonding between the functional groups in the alkyl chains, as well as the flexibility of the alkyl chains in these surfactants. The present study is crucial to understanding the relationship between the interfacial structures and the functionalities of the biodegradable quaternary ammonium surfactants.


Assuntos
Compostos de Amônio Quaternário/química , Tensoativos/química , Ligação de Hidrogênio , Estrutura Molecular , Compostos de Amônio Quaternário/metabolismo , Eletricidade Estática , Propriedades de Superfície , Tensoativos/metabolismo
9.
RSC Adv ; 12(39): 25280-25283, 2022 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-36199296

RESUMO

Herein we report a novel palladium-catalyzed phosphorylation of arylsulfonium salts with P(O)H compounds via C-S bond cleavage under mild conditions. The protocol provides a pragmatic strategy applicable to the synthesis of diverse arylphosphonates.

10.
RSC Adv ; 12(31): 20218-20226, 2022 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-35919589

RESUMO

In this paper, we report self-assembled sonogels formed from 1,4-naphthalenedicarbonyldinicotinic acid hydrazide (NDC-NN3) in some liquids including ethanol, tetrahydrofuran (THF), 1,4-dioxane, n-propanol, n-butanol and n-pentanol. When the clear solution of NDC-NN3 in the selected liquids mentioned above at a suitable concentration was irradiated with ultrasound waves at room temperature, a sonogel was formed. Upon heating, the sonogel dissolved gradually and finally became a clear solution again. Upon cooling the hot solution to room temperature, the solution state did not change even after standing for a few days. Nevertheless, if the solution underwent sonication for a certain time, a stable gel was obtained again. The critical gelation concentrations (CGCs) of NDC-NN3 in ethanol, THF, 1,4-dioxane, n-propanol, n-butanol and n-pentanol are 10, 8, 6, 8, 6 and 8 mg mL-1, respectively. The obtained sonogels display excellent mechanical properties. The crystal structure of NDC-NN3 suggests that the naphthalene ring, hydrazide group and the position of N in the pyridine ring mediate the self-assembly process. Upon sonication, the formation of suitable π-π stacking and intermolecular hydrogen bonding drives the gelator molecules to self-assemble into fibers, spheres and micro-burdock-shaped balls in various solvents, which ultimately confine the liquids.

11.
Front Aging Neurosci ; 14: 969822, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36268186

RESUMO

Background: Mild cognitive impairment (MCI) is considered a transitional stage between cognitive normality and dementia among the elderly, and its associated risk of developing Alzheimer's disease (AD) is 10-15 times higher than that of the general population. MCI is an important threshold for the prevention and control of AD, and intervention in the MCI stage may be the most effective strategy to delay the occurrence of AD. Materials and methods: In this study, 68 subjects who met the inclusion criteria were divided into an MCI group (38 subjects) and normal elderly (NE) group (30 subjects). Both groups underwent clinical function assessments (cognitive function, walking function, and activities of daily living) and dual-task three-dimensional gait analysis (walking motor task and walking calculation task). Spatial-temporal parameters were obtained and reduced by principal component analysis, and the key biomechanical indexes were selected. The dual-task cost (DTC) was calculated for intra-group (task factor) and inter-group (group factor) comparisons. Results: The results of the principal component analysis showed that the cadence parameter had the highest weight in all three walking tasks. In addition, there were significant differences in the cadence both walking motor task (WMT) vs. walking task (WT) and walking calculation task (WCT) vs. WT in the MCI group. The cadence in the NE group only showed a significant difference between WMT and WT. The only differences between the MCI group and NE group was DTC cadence in WCT, and no differences were found for cadence in any of the three walking tasks. Conclusion: The results show that dual tasks based on cognitive-motor gait analysis of DTCcadence in MCI have potential value for application in early identification and provide theoretical support to improve the clinical diagnosis of MCI.

12.
RSC Adv ; 11(19): 11519-11528, 2021 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-35423629

RESUMO

As one of the most important and fruitful methods, supramolecular self-assembly has a significant advantage in designing and fabricating functional soft materials with various nanostructures. In this research, a low-molecular-weight gelator, N,N'-di(pyridin-4-yl)-pyridine-3,5-dicarboxamide (PDA-N4), was synthesized and used to construct self-assembled gels via a solvent-mediated strategy. It was found that PDA-N4 could form supramolecular gels in mixed solvents of water and DMSO (or DMF) at high water fraction (greater than or equal to 50%). By decreasing the water fraction from 50% to 30%, the gel, suspension and solution phases appeared successively, indicating that self-assembled aggregates could be efficiently modulated via water content in organic solvents. Moreover, the as-prepared PDA-N4 supramolecular gels not only displayed solid-like behavior, and pH- and thermo-reversible characteristics, but also showed a solution-gel-crystal transition with the extension of aging time. Further analyses suggested that both the crystal and gel had similar assembled structures. The intermolecular hydrogen bonding between amide groups and the π-π stacking interactions between pyridine groups played key roles in gel formation. Additionally, the release behavior of vitamin B12 (VB12) from PDA-N4 gel (H2O/DMSO, v/v = 90/10) was evaluated, and the drug controlled release process was consistent with a first-order release mechanism. The human umbilical venous endothelial cell culture results showed that the PDA-N4 xerogel has good cytocompatibility, which implied that the gels have potential biological application in tissue engineering and controlled drug release.

13.
RSC Adv ; 9(21): 11824-11832, 2019 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-35517010

RESUMO

In this study, we report a pH-/thermo-responsive hydrogel formed by N,N'-dibenzoyl-l-cystine (DBC). It is difficult to dissolve DBC in water even on heating, and it exhibits no gelation ability. Interestingly, DBC is readily soluble in NaOH solution at room temperature and the self-assembled hydrogels are obtained by adjusting the basic DBC aqueous solution with HCl to achieve a given pH value (<3.5). When NaOH is added to the hydrogel (pH > 9.4), it becomes a sol again. This small-molecule hydrogel is characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, rheological measurement and differential scanning calorimetry. The results indicate that the DBC hydrogel exhibits excellent mechanical properties, thermo-reversibility, and pH-responsive properties. Fortunately, the single crystal of DBC is obtained by volatilizing its acid aqueous solution. It crystallizes in the monoclinic space group P21 (Z = 2) with lattice parameters a = 10.8180 (11) Å, b = 9.0405 (9) Å, c = 10.9871 (11) Å and ß = 90.798 (3)°. By comparing the X-ray diffraction result of the DBC single crystal with that of its xerogel, the self-assembled structure of DBC in hydrogel has been ascertained. The gelators are self-assembled via strong intermolecular hydrogen bonds linking neighboring amide and carboxyl groups, π-π stacking interactions for aromatic rings, and hydrogen bonds between water molecules. In addition, the release behavior of salicylic acid (SA) molecules from the DBC gel is also investigated taking into account the DBC concentration, phosphate buffer solution (PBS) pH and SA concentration. When the concentrations of DBC and SA are 3.0 g L-1 and 200 mg L-1, respectively, the release ratio in PBS (pH = 4.0) reaches 58.02%. The diffusion-controlled mechanism is in accordance with Fickian diffusion control within the given time range.

14.
Bioresour Technol ; 292: 121286, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31386946

RESUMO

Hydrothermal liquefaction of Ulva prolifera macroalgae (UM), an aquatic biomass, was carried out in an autoclave reactor at different temperature (270, 290 and 310 °C) and reaction holding time (10, 20 and 30 min.). The catalytic reactions of UM were carried out in the presence of three basic catalysts (KOH, NaOH and Na2CO3) with the different catalyst amount. Maximum bio-oil yield for non-catalytic liquefaction was (12.0 wt%) at 290 with 10 min reaction time. In the catalytic reaction the maximum bio-oil yield (26.7 wt%) was observed with KOH (0.1 g) catalyst. The chemical components and functional groups present in the bio-oils are identified by GC-MS, FT-IR, 1H-NMR, TGA and elemental analysis techniques. Majorly nitrogen containing compounds were found with catalytic reaction in bio-oils. The higher heating value (33.6 MJ kg-1) as well as the higher carbon content (64.2%) was observed in the case of catalytic liquefaction bio-oil.


Assuntos
Alga Marinha , Ulva , Biocombustíveis , Biomassa , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura
17.
J Phys Chem B ; 114(34): 11069-75, 2010 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-20698514

RESUMO

The molecular assemblies of 4-(hexadecyloxy)-N-(pyridinylmethylene)anilines (HPA) at the air-water interface on pure water and aqueous Cu(II) subphases have been investigated using in situ infrared reflection absorption spectroscopy (IRRAS). The Schiff base units were oriented with their long axes almost perpendicular to the water surface, and both imine and pyridinyl nitrogen atoms of the Schiff base units were coordinated to Cu(II) ions together with their geometrical conversions. The alkyl chains in the monolayers were quantitatively determined on the assumption that the HPA monolayers at the air-water interface were composed of sublayers of alkyl chains and Schiff base units, and the chain orientation angle on pure water was 30 +/- 2 degrees and increased to 37 +/- 2 degrees on the aqueous Cu(II) subphase. The HPA amphiphiles could not be dispersed in pure water but could self-organize into vesicles with metal-coordinated headgroups and interdigitated-packed alkyl chains in the presence of Cu(II) ions in aqueous solution. Transmission electron microscopy (TEM), differential scanning calorimetry (DSC), UV-vis spectroscopy, and small-angle X-ray diffraction (XRD) were used to investigate the aggregate structures and specific properties of the coordinated vesicles.

18.
Langmuir ; 25(5): 2941-8, 2009 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-19437705

RESUMO

The surface behaviors of monolayers of amino-acid-derived Schiff bases, namely, 4-(4-(hexadecyloxy)benzylideneamino)benzoic acid (HBA), at the air-water interface on pure water and ion-containing subphases (Cu2+, Ca2+, and Ba2+) have been clarified by a combination of surface pressure-area isotherms and surface plasmon resonance (SPR) technique, and the metal coordinations and molecular orientations in the monolayers have been investigated using in situ infrared reflection absorption spectroscopy (IRRAS). The presence of metal ions gives rise to condensation of the monolayers (Cu2+, pH 6.1; Ca2+, pH 11; Ba2+, pH 10), even leading to the formation of three-dimensional structures of the compressed monolayer in the case of Ba2+ (pH 12). The metal coordinations with the carboxyl groups at the interface depend on the type of metal ions and pH of the aqueous subphase. The orientations of the aromatic Schiff base segments with surface pressure are elaborately described. The spectral behaviors of the Schiff base segments with incidence angle in the case of Ba2+ (pH 12) have so far presented an excellent example for the selection rule of IRRAS at the air-water interface for p-polarization with vibrational transition moments perpendicular to the water surface. The chain orientations in the monolayers are quantitatively determined on the assumption that the thicknesses of the HBA monolayers at the air-water interface are composed of the sublayers of alkyl chains and Schiff base segments.


Assuntos
Química/métodos , Metais/química , Bases de Schiff/química , Ar , Bário/química , Ácido Benzoico/química , Cálcio/química , Cobre/química , Concentração de Íons de Hidrogênio , Íons , Modelos Químicos , Ressonância de Plasmônio de Superfície , Propriedades de Superfície , Fatores de Tempo , Água/química
19.
J Colloid Interface Sci ; 325(2): 391-7, 2008 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-18649893

RESUMO

Copper sulfide-poly(acrylamide-co-methacrylic acid) (CuS-P(AM-co-MAA)) composite microspheres with patterned surface structures have been synthesized in a controllable manner by means of the polymer microgel template method. The formation of CuS particles can be regulated by controlling the decomposition of thioacetamide (TAA) in acidic solution. Compared with the microgel template, the surface morphologies of the composite microspheres are characterized by compact and creased textures. The surface morphology of the composite microspheres has been found to be mainly influenced by the amount of copper sulfide precipitated and hence by the rate of H(2)S gas generation. This study might provide a potential route for controlling the synthesis of various metal sulfide-polymer composites with patterned surface structures.

20.
Langmuir ; 23(22): 11034-41, 2007 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-17902721

RESUMO

The chain orientation in the monolayers of amino-acid-derived Schiff base, 4-(4-dodecyloxy)-2-hydroxybenzylideneamino)benzoic acid (DSA), at the air-water interface has been determined using infrared reflection absorption spectroscopy (IRRAS). On pure water, a condensed monolayer is formed with the long axes of Schiff base segments almost perpendicular to the water surface. In the presence of metal ions (Ca2+, Co2+, Zn2+, Ni2+, and Cu2+) in the subphase, the monolayer is expanded and the long axes of the Schiff base segments are inclined with respect to the monolayer normal depending on metal ion. The monolayer thickness, which is an important parameter for quantitative determination of orientation of hydrocarbon chains, is composed of alkyl chains and salicylideneaniline portions for the DSA monolayers. The effective thickness of the Schiff base portions is roughly estimated in the combination of the IRRAS results and surface pressure-area isotherms for computer simulation, since the only two observable p- and s-polarized reflectance-absorbance (RA) values can be obtained. The alkyl chains with almost all-trans conformations are oriented at an angle of about 10 degrees for H2O, 15 degrees for Ca2+, 30 degrees for Co2+, 35 degrees -40 degrees for Zn2+, and 35 degrees -40 degrees for Ni2+ with respect to the monolayer normal. The chain segments linked with gauche conformers in the case of Cu2+ are estimated to be 40 degrees -50 degrees away from the normal.

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