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1.
J Chromatogr A ; 1727: 464969, 2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38776606

RESUMO

Polymerization of 5-n-alkyl-substituted 2-norbornenes synthesized a series of polymers having the same structure of the main polymer chain, but differing in the length of the alkyl substituent (up to 14 methylene units). The obtained polymers were studied by the capillary IGC method as a stationary phase during separation of a mixture of normal hydrocarbons C6-C10. Retention data in the form of a logarithm of the retention factor lnk were correlated with the size of the sorbate (via the carbon number of the alkane ZS) and with the size of the n-alkyl substituent in the polymer chain (via the carbon number of the polymer ZP). Correlation of lnk vs. ZS turned out to be linear for all polymers, but the angle of the slope of linear dependence dlnk/dZS increases with a decrease in the carbon number of the polymer ZP. Dependency of dlnk/dZS vs. ZP is not linear and indicates an increase in the retention of sorbates by the stationary phase with a decrease in the length of the alkyl substituent in the polymer chain. The correlation of the retention of lnk analytes with the carbon number of the polymer ZP is not linear and indicates an increase in the sorbate/sorbent interaction with a decrease in the length of the alkyl substituent. Inflection points were found at both correlations with ZP in the region of ZP = 8, which indicates a possible change in the sorption mechanism or a change in the phase state of the polymer. In polymer chemistry, the phase state of a polymer is characterized by the glass transition temperature Tg, the dependence of which vs. ZP turned out to be nonlinear with an inflection point at ZP ∼11. Thus, a decrease in the length of the alkyl substituent leads to the transition of the polymer from a rubbery state to a glassy one at ZP ∼ 11, which in turn, with a further decrease in the carbon number of the polymer to ZP ∼ 8, causes a change in the sorption mechanism from bulk sorption to surface sorption. The change in the sorption mechanism is accompanied by an increase in the interaction of the sorbate with the stationary phase, which manifests itself both in an increase in the retention time of analytes and in an increase in the enthalpy and entropy of sorption. The reason for this increase can be seen in the formation of a microporous structure in 5-alkyl-substituted polynorbornenes in a glassy state.

2.
Dokl Biol Sci ; 516(1): 27-31, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38538826

RESUMO

A rat biological model of septoplasty was used to study the effect of surgery on passive avoidance conditioning (PAC). Septoplasty was shown to increase anxiety and to reduce exploratory activity in rodents during PAC. A neurochemical analysis of the hypothalamus was carried out immediately after the end of the experiment and showed an increase in norepinephrine (NE) metabolism after septoplasty. The finding was tentatively associated with activation of the hypothalamic-pituitary-adrenal axis.


Assuntos
Aprendizagem da Esquiva , Hipotálamo , Animais , Ratos , Aprendizagem da Esquiva/fisiologia , Hipotálamo/metabolismo , Masculino , Norepinefrina/metabolismo , Ratos Wistar , Cavidade Nasal/metabolismo , Cavidade Nasal/cirurgia , Sistema Hipotálamo-Hipofisário/metabolismo , Septo Nasal/cirurgia , Septo Nasal/metabolismo
3.
Phys Rev E ; 108(1-2): 015207, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37583194

RESUMO

We propose an approximate method to calculate ion partition functions in the context of the chemical-picture representation of plasmas as an interacting mixture of various ions and free electrons under the local-thermodynamic-equilibrium conditions. The method uses the superconfiguration approach and implies that the first-order corrections to the energies of excited electron configurations due to the electron-electron interaction may be replaced by a similar first-order correction to the energy of the basic configuration of an ion with the same number of bound electrons. The method enables one to significantly speed up the calculations and generally provides quite accurate results. Using the method proposed, plasma ionization balance and average ion charges calculated on the base of the chemical-picture representation show a good agreement with the relevant average-atom data. For the case of weak electron-ion nonideality, we provide approximate relations between the chemical-picture and average-atom values of the average ion charge, chemical potential, and plasma-density depression of ionization potential.

4.
Dokl Biol Sci ; 509(1): 107-111, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37208576

RESUMO

Modeling septoplasty and modeling sensory deprivation of the olfactory analyzer in rats were compared for the effect on the frequency domain of heart rate variability (HRV). Bulbectomy provoked more pronounced changes in HRV as compared with septoplasty simulation.


Assuntos
Olfato , Ratos , Animais , Frequência Cardíaca/fisiologia , Olfato/fisiologia
5.
Microvasc Res ; 145: 104440, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36150473

RESUMO

STUDY PURPOSE: To conduct a cross-sectional study on the structural and functional characteristics of various parts of skin microcirculation in working-age men with newly diagnosed hypertension (HTN). MATERIALS AND METHODS: The study included 118 male participants (ages 30 to 60) who were not regularly taking any medicine, had no medical complaints, and subjectively considered themselves healthy at the time of study. All participants underwent a cross-sectional comprehensive medical examination. The following tests were performed: complete blood count, biochemical blood tests, video capillaroscopy (VCS), laser Doppler flowmetry (LDF) and photoplethysmography (PPG) on the left hand fingers, determination of flow-mediated vasodilation of the brachial artery, echocardiography, ultrasound of extracranial and femoral arteries, 24-h ambulatory blood pressure monitoring (ABPM). According to ABPM data, the participants were divided into two equal groups called a control group(CG) and a hypertension group(HG). There were 59 participants with normal BP in CG, and 59 participants with newly diagnosed HTN in HG. RESULTS: Nailfold VCS of the ring finger revealed no significant differences between the groups at the level of exchange microvessels. According to LDF data, there was no decrease in tissue perfusion and signs of an increase in the activity of endothelial, neurogenic, and myogenic regulation of the tone of precapillary arterioles in the HTN group. According to PPG of the index finger, in contrast to CG, HTN participants had significantly higher values of the following parameters: normalized augmentation index (Alp75) - 3.8 % and - 5.25 % (p < 0.005), stiffness index (SI) - 7.6 m/s and 7.35 m/s (p < 0.05), reflection index (RI) - 36.5 % and 28.4 % (p < 0.005), respectively. DISCUSSION: Working-age men in the early stage of HTN have neither capillary rarefaction nor an increase in the tone of skin precapillary arterioles. The largest contribution to peripheral vascular resistance in the onset of HTN is most likely made by large muscular arterioles, in which the neurogenic regulation of vascular tone predominates.


Assuntos
Monitorização Ambulatorial da Pressão Arterial , Hipertensão , Humanos , Masculino , Adulto , Pessoa de Meia-Idade , Microcirculação , Estudos Transversais , Velocidade do Fluxo Sanguíneo , Fluxometria por Laser-Doppler , Hipertensão/diagnóstico , Pele/irrigação sanguínea
6.
Artigo em Russo | MEDLINE | ID: mdl-38289307

RESUMO

INTRODUCTION: Subacromial impingement syndrome is a common pathology that leads to a persistent decrease in the functioning of the affected limb and, as a consequence, a decrease in the quality of life and work ability of patients. According to various authors, the study of the effectiveness of treatment and rehabilitation of this pathology is quite widely presented in the literature: surgical, including arthroscopic operations, rehabilitation using various factors of physical therapy, manual and other practices. However, the issue of assessing the effectiveness of movement therapy, both alone and in combination with other therapeutic methods, remains relevant. AIM: To evaluate the effectiveness of therapeutic gymnastics procedures, both monotherapy and in combination with manual massage according to the therapeutic method and extracorporeal shock wave therapy (ESWT), in patients with subacromial impingement syndrome of the shoulder, in order to reduce pain and improve the function of the shoulder joint. MATERIAL AND METHODS: The study included 70 patients whose age was 42.18±10.42 years. Patients were divided into two main groups: group 1 (n=34) and group 2 (n=36). All patients received a course of treatment, including 10 procedures of therapeutic exercises, with recommendations at the end of the course for continuation in the form of independent studies using the proven methodology. The duration of the course of therapeutic exercises (in the form of procedures with a physical therapy instructor and subsequent independent studies) was 30 days. Patients in group 2 were divided into three subgroups: subgroup 2A, in which PH procedures were combined with massage of the cervical-collar area and the upper limb area of the affected side; subgroup 2B, where PH gymnastics was carried out in combination with extracorporeal shock wave therapy (ESWT) procedures; subgroup 2C - a comprehensive program including LH procedures, manual massage and shock wave therapy. RESULTS: 3 months after the end of the course of rehabilitation measures, patients of all groups showed a significant improvement in scores on the ASES and VAS scales, but there were no reliably significant differences between the results of different groups. CONCLUSION: The study indicates that movement therapy is an effective method of rehabilitation for patients with subacromial impingement syndrome, and conducting complex programs in which PH is combined with other rehabilitation methods (massage, shock wave therapy) doesn't have statistically significant advantages over PH alone within a 3-month observation period.


Assuntos
Tratamento por Ondas de Choque Extracorpóreas , Síndrome de Colisão do Ombro , Humanos , Adulto , Pessoa de Meia-Idade , Síndrome de Colisão do Ombro/terapia , Qualidade de Vida , Terapia por Exercício , Ginástica
8.
Clin Hemorheol Microcirc ; 80(4): 373-387, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34719487

RESUMO

OBJECTIVE: To investigate structural and functional features of cutaneous microvasculature in men of working age with newly diagnosed arterial hypertension (AH). MATERIALS AND METHODS: The study included 161 apparently healthy men from 30 to 60 years, who underwent a comprehensive examination of cardiovascular system "from the heart to the capillaries". Control group (CG) included 60 normotensive men. AH group included 101 men with elevated BP. RESULTS: There is no rarefaction of the capillary bed and latent fluid retention in the interstitial space in the skin in men with AH. No data were obtained for increased endothelial, neurogenic and myogenic tone of resistive cutaneous precapillary arterioles in AH group, but a decrease in the perfusion efficiency of the endothelial and myogenic mechanisms of tissue perfusion modulation was noted. CONCLUSION: Obtained results allow making the assumption that metabolic disorders at the level of capillaries that are of a systemic nature prevail in men with the onset of AH.


Assuntos
Hipertensão , Pressão Sanguínea , Capilares , Humanos , Fluxometria por Laser-Doppler , Masculino , Microcirculação , Pele/irrigação sanguínea
9.
Rev Sci Instrum ; 92(5): 054706, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-34243317

RESUMO

In this paper, an ultra-low-voltage crystal quartz oscillator is proposed. The design of the proposed oscillator is essentially based on using a HEMT operating in an unsaturated dc regime and a quartz resonator as a resonant impedance transformer. The 25 MHz prototype shows steady oscillations at the supply voltage of less than 17 mV and the power consumption as low as 300 nW, i.e., 1-2 orders of magnitude lower than the other to-date oscillators. This approach is good for building ultra-low consumption radio devices including those working at low temperatures.

10.
Khirurgiia (Mosk) ; (5): 109-124, 2021.
Artigo em Russo | MEDLINE | ID: mdl-33977706

RESUMO

OBJECTIVE: To conduct a systematic review of modern literature data on the modern approaches in diagnosis and treatment of shoulder instability. MATERIAL AND METHODS: Searching for literature data was performed using the Pubmed and Google Scholar databases. RESULTS: The authors analyzed the results of conservative treatment of patients with shoulder instability and emphasized higher risk of instability recurrence, degeneration of anatomical structures and functional impairment in these patients. Surgery is advisable to restore shoulder stability and normalize its function. Several methods for stabilizing the shoulder have been proposed.The approaches to diagnosis and treatment of shoulder instability have been updated. CONCLUSION: Successful treatment of shoulder instability is based on qualitative and complete assessment of soft tissues and bone structures. An individual approach considering bone tissue deficiency and individual needs of the patient is required.


Assuntos
Instabilidade Articular , Luxação do Ombro , Articulação do Ombro , Artroscopia , Humanos , Instabilidade Articular/diagnóstico , Instabilidade Articular/terapia , Amplitude de Movimento Articular , Recidiva , Ombro
11.
Khirurgiia (Mosk) ; (9): 130-136, 2020.
Artigo em Russo | MEDLINE | ID: mdl-33030014

RESUMO

The analysis of literature data was performed on the pathogenesis, diagnosis and treatment of injuries of the posterior cruciate ligament (PCL) of the knee joint. PCL is the largest intra-articular ligament of the knee joint, can withstand the maximum loads compared with other ligaments. It was noted that, in general, in cases of damage to the PCL, it is necessary to use a set of diagnostic methods, and the basic principles for the choice of optimal treatment plan for this patient. It considered the results of the conservative treatment of PCL partial ruptures, and it is indicated that this approach increases the risk of degenerative anatomical structures and functional disorders of the joint. It was noted that it is advisable to conduct surgical treatment to restore the stability of the knee joint and normalize function, while a number of methods for the reconstruction of PCL have been proposed to date. The usage of chondroprotectors for prevention of the secondary osteoarthrosis of the knee joint affected by posterior cruciate ligament rupture was analyzed in the literature data.


Assuntos
Instabilidade Articular , Osteoartrite , Ligamento Cruzado Posterior , Fenômenos Biomecânicos , Humanos , Articulação do Joelho , Osteoartrite/prevenção & controle , Prevenção Secundária
12.
Bull Exp Biol Med ; 168(3): 341-344, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31940131

RESUMO

Standard water-reinforced drug discrimination model was employed to train Wistar rats to discriminate the intraperitoneal injections of tricyclic antidepressant amitriptyline (5.4 mg/kg) and physiological saline. To examine the role of GABAA receptors in psychotropic action of amitriptyline, the substitution tests were performed with muscimol (0.1-1.0 mg/kg) and pregnenolone (30-50 mg/kg). Similar tests were carried out with amitriptyline interoceptive antagonists bicuculline (1 mg/kg), flumazenil (15 mg/kg), finasteride (5 mg/kg), and indomethacin (7.5 mg/kg). The study showed that interoceptive effects of amitriptyline depend on functional activity of GABAA receptors but not on the neurosteroid site of GABAA receptor complex.


Assuntos
Amitriptilina/farmacologia , Psicotrópicos/farmacologia , Receptores de GABA-A/metabolismo , Animais , Bicuculina/farmacologia , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/metabolismo , Agonistas de Receptores de GABA-A/farmacologia , Antagonistas de Receptores de GABA-A/farmacologia , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Masculino , Muscimol/farmacologia , Núcleo Accumbens/efeitos dos fármacos , Núcleo Accumbens/metabolismo , Pregnenolona/farmacologia , Ratos , Ratos Wistar
13.
Urologiia ; (4): 80-84, 2019 Sep.
Artigo em Russo | MEDLINE | ID: mdl-31535810

RESUMO

PURPOSE: To evaluate erectile function in patients with Peyronies disease (PD) who underwent corporoplasty. MATERIALS AND METHODS: A total of 374 patients who underwent corporoplasty by a single surgeon during 1996-2016 were analyzed. In all cases IIEF questionnaire was evaluated pre- and postoperatively. Intracavernous injection test and penile doppler ultrasonography were performed if required. Median follow-up was 9.5 years. Analysis of risk factors for erectile dysfunction (ED) before and after corporoplasty was performed. RESULTS: Prevalence of risk factors for ED in our sample has greatly increased during follow-up. At the last follow-up visit 285 patients were sexually active. Evaluation of patient satisfaction with the quality of erections has shown that 139 patients were fully satisfied (48.8%), 84 patients were somewhat satisfied (29.5%) and 62 patients were not satisfied with their erectile function (21.7%). According to IIEF questionnaire, 105 patients (36.8%) had no ED (> 26 points); 74 patients (26%) had mild ED; 67 patients (23.5%) had mild-to-moderate ED; 21 patients (7.4%) had moderate ED; and 18 patients (6.3%) had severe ED. However, a causal relationship between ED and treatment of Peyronie's disease was found not in all cases. Seven patients had infrequent sexual intercourse (1-2 per month) and 50 patients had no sexual activity. DISCUSSION: At long term after corporoplasty some patients experience ED, though causality between ED and PD treatment couldnt be confirmed in all such cases. It should be noted that we have found an increase in prevalence of independent risk factors for ED during follow-up period. These patients could possibly benefit in terms of quality of life if they underwent penile prosthesis placement during primary surgical treatment for PD. However, some patients had no sexual activity due to causes unrelated to ED. CONCLUSION: Not all patients with PD are satisfied with their sexual functioning after corporoplasty. However, ED after surgical management of PD is not always a consequence of surgery itself.


Assuntos
Disfunção Erétil , Induração Peniana , Humanos , Masculino , Satisfação do Paciente , Ereção Peniana , Pênis , Qualidade de Vida
14.
J Chromatogr Sci ; 57(9): 778-783, 2019 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-31504304

RESUMO

Chromatographic determination of the thermodynamic parameters of sorption for light hydrocarbons retention on a stationary phase based on poly [trimethylsilyl (propyn-1)] (PTMSP) was performed and the effect of column preheating at temperatures up to 260°C on the retention of analytes was investigated. It was shown that heating the column to 130°C does not affect the retention of the analytes. At temperatures above 130°C, the gradual decrease of the retention of analytes on PTMSP stationary phase is observed. The process is non-selective and proceeds at the same extent for all the studied hydrocarbons, regardless of the size and geometry of the molecule. Values of enthalpy and entropy of sorption of light hydrocarbons are determined for the original column and after its aging at 200°C. The enthalpy of sorption of the analytes at the PTMSP phase is practically independent on the heating temperature of the PTMSP phase, whereas the loss of entropy increases after heating. The increase of the entropy factor after the heating of the PTMSP stationary phase is associated with its aging and is confirmed by the construction of compensation functions for treated and untreated columns.

15.
Sci Rep ; 9(1): 8573, 2019 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-31189927

RESUMO

The increasing trend of large carnivore attacks on humans not only raises human safety concerns but may also undermine large carnivore conservation efforts. Although rare, attacks by brown bears Ursus arctos are also on the rise and, although several studies have addressed this issue at local scales, information is lacking on a worldwide scale. Here, we investigated brown bear attacks (n = 664) on humans between 2000 and 2015 across most of the range inhabited by the species: North America (n = 183), Europe (n = 291), and East (n = 190). When the attacks occurred, half of the people were engaged in leisure activities and the main scenario was an encounter with a female with cubs. Attacks have increased significantly over time and were more frequent at high bear and low human population densities. There was no significant difference in the number of attacks between continents or between countries with different hunting practices. Understanding global patterns of bear attacks can help reduce dangerous encounters and, consequently, is crucial for informing wildlife managers and the public about appropriate measures to reduce this kind of conflicts in bear country.


Assuntos
Animais Selvagens/fisiologia , Conservação dos Recursos Naturais , Ursidae/fisiologia , Animais , Feminino , Humanos , Masculino
16.
Urologiia ; (5): 114-121, 2018 Dec.
Artigo em Russo | MEDLINE | ID: mdl-30575361

RESUMO

Varicocele-related infertility is traditionally considered an indication for surgery. At the same time in some specific clinical settings, especially with subclinical varicocele, conservative therapy using hormonal or antioxidant drugs is also possible. The potential role of drug therapy in this patient category remains controversial. The article discusses the options and treatment regimens for men with varicocele-related infertility. Given the difficulties in interpreting the results of studies and the heterogeneity of the data, it is not yet possible to recommend abandoning varicocelectomy in favor of drug therapy. The most promising option for drug therapy is adjuvant antioxidants after surgical treatment of varicocele.


Assuntos
Infertilidade Masculina , Varicocele , Antioxidantes , Humanos , Masculino , Varicocele/tratamento farmacológico , Procedimentos Cirúrgicos Vasculares
17.
Vopr Pitan ; 87(5): 20-26, 2018.
Artigo em Russo | MEDLINE | ID: mdl-30592887

RESUMO

Lutein and zeaxanthin are carotenoid pigments that affect the function of the visual analyzer. They selectively accumulate in the yellow spot of the retina, form macular pigment and determine the density of the retina macula. Lutein and zeaxanthin slow down the progression of age-related macular degeneration, a leading cause of senior-age blindness. The main food sources of non-vitamin carotenoids are green leafy vegetables, zucchini, pumpkin, green peas, broccoli. The aim of the study is a retrospective assessment of the levels and sources of alimentary intake of lutein and zeaxanthin in young people and research of the effect of lutein and zeaxanthin in the diet on macula density. A specially designed questionnaire was used to quantify the content of lutein and zeaxanthin in the diet, reflecting the amount of consumption of the main sources of these carotenoids on the day preceding the survey. A non-invasive non-contact method of optical coherence tomography of the retina was used to determine the density of the macula. The study involved 96 students of Sechenov University at the age of 21-27 years. The study found that only 6.25% of the respondents had daily intake of lutein and zeaxanthin of 6 mg or more, 8.33% had 4.6-5.9 mg, 8.33% had 3.0-4.5 mg, in 18.75% - 1.5-2.9 mg, in 45.83% <1.4 mg. 12.5% of respondents didn't include sources of lutein and zeaxanthin in the diet. The more common sources of lutein and zeaxanthin in the diet were eggs and fresh tomatoes. Retinal density indices corresponded to the age standards in the majority of the examined. In 8.3% surveyed the thickness of the retina was decreased, and 4.2% had higher thickness of the retina in comparison with the standards. Significant differences in the Central subfield thickness in men and women were revealed. There was no dependence of the levels of lutein and zeaxanthin coming from food sources on the retina thickness indicators.


Assuntos
Carotenoides , Dieta , Ingestão de Alimentos , Luteína , Macula Lutea , Tomografia de Coerência Óptica , Zeaxantinas , Adulto , Carotenoides/administração & dosagem , Carotenoides/análise , Feminino , Análise de Alimentos , Humanos , Luteína/administração & dosagem , Luteína/análise , Macula Lutea/diagnóstico por imagem , Macula Lutea/metabolismo , Masculino , Estudos Retrospectivos , Zeaxantinas/administração & dosagem , Zeaxantinas/análise
18.
Vopr Pitan ; 87(6): 22-27, 2018.
Artigo em Russo | MEDLINE | ID: mdl-30763487

RESUMO

A number of studies have shown the relationship between the regular consumption of cruciferous vegetables and the risk of malignant tumors in certain localizations, the activation of mechanisms of alimentary adaptation of the organism under conditions of alien loads, by inducing enzymes of the biotransformation system of xenobiotics. The cruciferous vegetables are distinguished by the presence of minor components, such as indole-3-carbinol, formed during the hydrolysis of glucosinolates. The aim of the investigation was a retrospective study of the content of indoles in students' diet with subsequent quantitative analysis in different comparison groups. The study involved 250 students from a medical university aged 21 to 27 years. To assess the actual nutrition, the developed questionnaires were used, which included the most common products in the Moscow region, sources of indole glucosinolates. It was found that 44% of the respondents didn't include cruciferous vegetables in the diet, and of those who consumed sources of indoles (56% of respondents), only about half received them in the recommended amount. It should also be noted that as in men, in women the most commonly used in the diet product as a source of indoles was cabbage, it was included in the diet of 68% of the respondents who used cruciferous vegetables, rarely pekin cabbage was used (16.3%) and broccoli (16.3%). Cauliflower, radishes, Kale and horseradish was included in the diet of 7.8-14.9% of the students. Less often turnip was consumed - only by 2.1% of the students. No significant differences in the consumption of indoles in the student with deficient, normal or overweight was revealed. Also, there was no correlation between excess weight and the consumption of various indoles sources. The obtained results testify to the extremely low level of alimentary intake of indole-3-carbinol.


Assuntos
Brassicaceae , Dieta , Indóis/administração & dosagem , Estudantes de Medicina , Inquéritos e Questionários , Verduras , Adulto , Feminino , Humanos , Masculino , Moscou , Neoplasias/etnologia , Neoplasias/prevenção & controle , Estudos Retrospectivos
19.
J Chromatogr A ; 1533: 174-179, 2018 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-29276080

RESUMO

Enthalpy and entropy of adsorption of polar and non-polar solutes were measured by chromatographic technique for new stationary phases prepared from membrane polymers based on tricyclonones. Data obtained within temperature interval from 40 to 150 °C were used to create extrathermodynamic dependences (compensation plots, dependences of enthalpy and entropy changes on solute carbon number). Compensation plots were very similar for all the stationary phases indicating similar adsorption mechanisms. The difference between the stationary phases was elucidated using dependences of enthalpy and entropy changes on solute carbon number. Higher retentivity of the stationary phase based on polymer 1 was explained by higher both enthalpy and entropy of solute adsorption on the stationary phase.


Assuntos
Técnicas de Química Analítica/métodos , Hidrocarbonetos/química , Polímeros/química , Adsorção , Cromatografia , Entropia , Temperatura , Termodinâmica
20.
Anal Chim Acta ; 986: 153-160, 2017 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-28870321

RESUMO

Norbornene polymers with intrinsic porosity were investigated as candidates for polymeric stationary phases in capillary GC. Kinetic and thermodynamic characteristics of the stationary phases were evaluated and turned out that only polymer with vicinal distribution of trimethylsilyl groups (polymer II) provided properties making it potential candidate for application in capillary GC. Columns with stationary phase based on polymer II demonstrated unique selectivity, moderate thermostability and efficiency better than previously studied columns with stationary phase based on poly[(1-trimethylsilyl)-1-propine].

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