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1.
Parasitol Res ; 123(1): 83, 2024 Jan 06.
Artículo en Inglés | MEDLINE | ID: mdl-38182821

RESUMEN

Nine species-level taxa of bat ectoparasites, three chigger mites (Trombiculidae), three hard (Ixodidae), and one soft tick (Argasidae) species, as well as two bug (Cimicidae) species from nine bat species hosts were detected in the Eastern Palaearctic. Trombiculid larvae of Leptotrombidium schlugerae, Leptotrombidium album, and Ascoschoengastia latyshevi were first recorded on bats in the temperate zone of eastern Russia. L. schlugerae was more abundant than A. latyshevi in the same study sites in Eastern Siberia, and the main hosts of both chigger species were Plecotus ognevi and Eptesicus nilssonii. Ixodid ticks Dermacentor marginatus, Ixodes simplex, and Ixodes sp. were sampled from bats in Kazakhstan, the Far East, and Eastern Siberia, respectively. Phylogenetic analysis based on Cox1, 16S rDNA, and ITS2 sequences of I. simplex showed that the specimens from the Far East grouped into a clade distributed in the Eastern Palaearctic and India. In turn, the specimen of Ixodes sp. from Eastern Siberia was most closely related to Ixodes soricis and Ixodes angustus with p-distance of 9.8-10.7% (Cox1), suggesting that this tick probably belongs to a new species. Argas vespertilionis larvae were collected from three widespread bat species in Kazakhstan. Two bug species, Cimex pipistrelli and Cimex aff. lectularius, were recorded in the Far East and Eastern Siberia, respectively. Specimens from Transbaikalia were morphologically identified as Cimex lectularius. However, they differed from the latter by 12.5-12.9% of Cox1 sequences, indicating that C. aff. lectularius may be a new species.


Asunto(s)
Argasidae , Chinches , Quirópteros , Ixodes , Ixodidae , Trombiculidae , Animales , Filogenia , Larva
2.
Pol Merkur Lekarski ; 51(5): 504-510, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38069851

RESUMEN

OBJECTIVE: Aim: reveal in social work the possibilities of applying adaptive physical activity in the process of social inclusion of persons with disabilities. PATIENTS AND METHODS: Materials and Methods: To obtain factual information, the survey method (questionnaire) and a complex of mathematical statistics methods were used: methods of descriptive statistics and correlation analysis. Statistical analysis was performed using SPSS Statistics 24.0.0. A total of 102 anonymous respondents took part in the focus groups. RESULTS: Results: The connection between adaptive physical activity and the increase in the level of social inclusion of persons with disabilities, in particular, former military personnel and war veterans, was investigated. It was determined that social work professionals can use adaptive physical activity tools to promote the social inclusion of persons with disabilities and other low-mobility population groups. CONCLUSION: Conclusions: It was established that the ways of using adaptive physical activity tools by social workers for the social inclusion of persons with disabilities are most often socio-psychological, physical, professional rehabilitation, social support, and preventive activities. New opportunities for the implementation of social inclusion by means of adaptive physical activity of persons with disabilities as a result of military operations are opened in connection with the introduction of the position of «helper (assistant) of a veteran in the community¼, which will be held by a social worker.


Asunto(s)
Personas con Discapacidad , Veteranos , Humanos , Inclusión Social , Personas con Discapacidad/psicología , Personas con Discapacidad/rehabilitación , Servicio Social , Veteranos/psicología , Ejercicio Físico
3.
Wiad Lek ; 76(10): 2308-2312, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37948731

RESUMEN

OBJECTIVE: The aim: To determine the dynamics of galectin-3 in the formation of the patient's clinical profile and the impact on structural cardiac and vascular remodeling in patients with myocardial infarction after reperfusion therapy. PATIENTS AND METHODS: Materials and methods: 140 patients with class II A CHF syndrome according to Vasilenko-Strazhesko FC II-III (NYHA), which occurred in patients with MI, and 22 patients with MI without signs of CHF were examined. RESULTS: Results: The average serum galectin-3 level of the studied patients was analyzed. The average concentration of galectin-3 in patients with stenting without signs of CHF was (10.87±1.65) ng/ml comparing to (6.57±0.21) ng/ml in healthy subjects (p<0.05). An increase in the concentration of this indicator was observed in the group of patients with CHF after MI with reperfusion - (35.2±1.76) ng/ml, which is significantly higher in comparison with practically healthy subjects, and in patients without revascularization it was (38.94±1.97) ng/ml (p<0.001). Positive correlations of medium strength were found between left ventricular end-systolic volume (ESV), left ventricular end-diastolic volume (LVEDV) and serum galectin-3 concentration in the examined patients. The correlation coefficient between the abovementioned indicators was 0.60 (p<0.01) and 0.53 (p<0.05), respectively. CONCLUSION: Conclusions: It has been determined that in patients with CHF with postinfarction cardiosclerosis there is a direct correlation of medium strength between the values of indicators of LV myocardial remodeling with plasma galectin-3 concentration, including ESV, EDV, in examined patients. The role of galectin-3 as a marker of postinfarction remodeling in patients with CHF for early diagnosis, prognosis, and risk stratification has been presented.


Asunto(s)
Galectina 3 , Infarto del Miocardio , Humanos , Remodelación Vascular , Corazón , Infarto del Miocardio/cirugía , Reperfusión
4.
Polymers (Basel) ; 15(19)2023 Oct 07.
Artículo en Inglés | MEDLINE | ID: mdl-37836067

RESUMEN

More than five hundred images of individual macromolecules of random styrene-butadiene copolymers and styrene-isoprene block copolymers dissolved in a polystyrene matrix were analyzed. The presence of density fluctuations inside the macromolecular coil has been established. Within the framework of the model of harmonic oscillations, the radial distribution of such density fluctuations is estimated.

5.
Int J Mol Sci ; 24(19)2023 Sep 22.
Artículo en Inglés | MEDLINE | ID: mdl-37833860

RESUMEN

A comparative study of anticorrosive inhibited polymer films on the tungsten surface formed from an aqueous solution of inhibited formulations (INFOR) containing organosilane and corrosion inhibitors was carried out by means of the prolonged exposure of a tungsten product in a modifying solution and by the method of cataphoretic deposition (CPD). Depending on the method of forming films on tungsten, the molecular organization of the near-surface layers was studied (ATR-FTIR), and the subprimary structure of the films was explored (TEM). The optimal modes of cataphoresis deposition (CPD duration and current density applied to the sample) for the formation of a protective inhibited polymer film on the tungsten surface were established by means of SEM. The energy and thermochemical characteristics (sessile drop and DSC methods), as well as operational (adhesive behavior) and protective filming ability (EIS and corrosion behavior), according to the method of formation of inhibited polymer film, were determined. Based on the combined characteristics of the films obtained by the two methods and the deposition modes, the CPD method showed better performance than the electroless dipping method.


Asunto(s)
Polímeros , Tungsteno , Polímeros/química , Tungsteno/química , Composición de Medicamentos , Películas Cinematográficas
6.
Molecules ; 28(13)2023 Jul 07.
Artículo en Inglés | MEDLINE | ID: mdl-37446921

RESUMEN

Data on the solubility of oligomer polystyrene (PS) and poly(methyl methacrylate) (PMMA) of various molecular weights have been obtained. The binodal and spinodal curves of the phase state diagram with the upper critical solution temperature (UCST) are constructed through simulation within the framework of the Flory-Huggins theory. The influence of the molecular weight of polymers on the contribution to their mixing has been compared, and correlation curves have been plotted. The interaction parameters were calculated and the mixing thermodynamics of the components was evaluated. The largest contribution was made by the entropy component. Also, it has been shown using IR spectroscopy that there is no interaction between the functional groups of polystyrene and poly(methyl methacrylate) in a homogeneous mixture.


Asunto(s)
Polimetil Metacrilato , Poliestirenos , Poliestirenos/química , Polimetil Metacrilato/química , Peso Molecular , Polímeros/química , Termodinámica
7.
Wiad Lek ; 76(4): 695-702, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37226604

RESUMEN

OBJECTIVE: The aim: To assess and compare the risk of maternal/perinatal complications and adverse outcomes in pregnancy and childbirth conceived by ART with those conceived naturally in Ukraine. PATIENTS AND METHODS: Materials and Methods: We conducted a retrospective multicenter cohort study from January 1st, 2019 to December 31st, 2021. This study included pregnant women who delivered at 14 Women's Hospitals from 8 regions of Ukraine. RESULTS: Results: A total of 21,162 pregnancies were included. Of these, there were 19,801 natural pregnancies and 1,361 pregnancies after ART. The proportion of ART. pregnancies has increased every year in during study period, peaking in 2021 (6.7%). Data analysis showed that the risks of gestational diabetes, preeclampsia, moderate or severe anemia, liver-related diseases, thyroid-related diseases, preterm birth, placenta previa, postpartum hemorrhage, and cesarean section were significantly increased in ART pregnancy. For neonatal outcomes, women conceived by ART were more likely to have twins. The effects of ART on the risk of premature rupture of membrane, cord entanglement, intrapartum fever, and cesarean section were more pronounced in singletons pregnancies. CONCLUSION: Conclusions: Women conceived by ART were at increased risks of several adverse pregnancy outcomes compared with women conceived naturally. Therefore, prenatal and intrapartum monitoring should be strengthened, and neonatal outcomes should be closely observed for ART pregnancy.


Asunto(s)
Cesárea , Nacimiento Prematuro , Recién Nacido , Embarazo , Humanos , Femenino , Estudios de Cohortes , Ucrania/epidemiología , Técnicas Reproductivas Asistidas/efectos adversos
8.
Polymers (Basel) ; 16(1)2023 Dec 30.
Artículo en Inglés | MEDLINE | ID: mdl-38201795

RESUMEN

Phase equilibria, interdiffusion and structure in the initial uncured mixtures of epoxy oligomer-polysulfone-alkyl glycidyl ether were studied. Binodal curves were constructed on isothermal sections of the ternary phase diagram. Thermodynamic mixing parameters were calculated and spinodal curves were plotted. The interdiffusion coefficients of components, establishing the technological modes of mixing the components, were determined. To validate the phase diagram, the phase structure of mixtures, the composition of which at a temperature of 40 °C corresponds to heterogeneous and homogeneous regions, was studied.

9.
Redox Rep ; 27(1): 221-229, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36200601

RESUMEN

OBJECTIVES: Many plant-derived anti-aging preparations influence antioxidant defense system. Consumption of food supplemented with chili pepper powder was found to extend lifespan in the fruit fly, Drosophila melanogaster. The present study aimed to test a connection between life-extending effect of chili powder and antioxidant defense system of D. melanogaster. METHODS: Flies were reared for 15 days in the mortality cages on food with 0% (control), 0.04%, 0.12%, 0.4%, or 3% chili powder. Antioxidant and related enzymes, as well as oxidative stress indices were measured. RESULTS: Female flies that consumed chili-supplemented food had a 40-60% lower glutathione-S-transferase (GST) activity as compared with the control cohort. Activity of superoxide dismutase (SOD) was about 37% higher in males that consumed food with 3% chili powder in comparison with the control cohort. Many of the parameters studied were sex-dependent. CONCLUSIONS: Consumption of chili-supplemented food extends lifespan in fruit fly cohorts in a concentration- and gender-dependent manner. However, this extension is not mediated by a strengthening of antioxidant defenses. Consumption of chili-supplemented food does not change the specific relationship between antioxidant and related enzymes in D. melanogaster, and does not change the linkage of the activities of these enzymes to fly gender.


Asunto(s)
Antioxidantes , Drosophila melanogaster , Animales , Antioxidantes/metabolismo , Femenino , Alimentos Fortificados , Glutatión , Masculino , Estrés Oxidativo , Polvos/farmacología , Superóxido Dismutasa/metabolismo , Transferasas/farmacología
10.
Wiad Lek ; 75(8 pt 1): 1888-1894, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36089874

RESUMEN

OBJECTIVE: The aim: Coverage of the American experience of successful application of professional ethics of social workers in the field of health to solve complex ethical dilemmas in the activity of a social worker. PATIENTS AND METHODS: Materials and methods: The methodological basis of the study was the use of an axiological approach in identifying the values and ethics of the professional activity of social workers, a competence approach in determining the competence of a social work specialist in the field of health in matters of professional ethics, an interdisciplinary approach in integrating the ethical competence of a social work specialist in the practice of solving ethical dilemmas in the field of health, including in the process of work of an interdisciplinary team of specialists. CONCLUSION: Conclusions: The content and specifics of the practical application of the Code of Professional Ethics of the National Association of Social Workers of the USA in social work in the field of health were studied. It was determined that many situations in the practice of social work do not have simple answers when solving complex ethical issues in the field of health. Social workers, in addition to the values, principles and standards of the Code, in making decisions about professional actions in the field of health, must take into account their own beliefs and those of the client. The mechanism for the adjustment of difficult ethical choice cases in the practice of a social worker in the field of health is described.


Asunto(s)
Ética Profesional , Trabajadores Sociales , Toma de Decisiones , Humanos , Principios Morales , Servicio Social , Estados Unidos
11.
Breast ; 65: 145-150, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-35970028

RESUMEN

BACKGROUND: HER2-positive breast cancers are rare amongst BRCA mutation carriers. No data exist regarding clinicopathological characteristics and prognosis of this subgroup of patients. MATERIALS AND METHODS: Using a retrospective matched cohort design, we collected data from 700 women who were diagnosed with operable invasive breast cancer from January 2006 to December 2016 and were screened for germline BRCA mutations. Clinicopathological features and survival rates were analyzed by BRCA and HER2 status. RESULTS: One hundred and fifteen HER2-positive/BRCA mutated cases were evaluated in comparison to the three control groups: HER2-positive/BRCA wild type (n = 129), HER2-negative/BRCA mutated (n = 222), HER2-negative/BRCA wild type (n = 234). HER2-positive breast cancers were more likely to have high histologic grade and high proliferation rate than HER2-negative neoplasms, regardless of BRCA mutation status. An interaction between BRCA mutations and HER2-positive status was found to correlate with worse survival after adjusting for prognostic variables (HR = 3.4; 95% CI: 1.3-16.7). CONCLUSIONS: Co-occurrence of BRCA mutations and HER2-positive status is a poor prognostic factor in patients with early or locally advanced breast cancer. This finding may be a proof of concept that a combined pharmacological intervention directed to these targets could be synergistic.


Asunto(s)
Neoplasias de la Mama , Neoplasias de la Mama/patología , Femenino , Células Germinativas/patología , Mutación de Línea Germinal , Humanos , Mutación , Pronóstico , Estudios Retrospectivos
12.
Polymers (Basel) ; 14(13)2022 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-35808572

RESUMEN

A new approach is proposed for simulating binodal and spinodal curves of phase diagrams for binary polymer systems. It is shown that the Flory-Huggins theory makes it possible to predict phase behavior in a wide range of temperatures and concentrations based on limited data on the components' solubility. The approbation data of the technique are presented in the example of PS-PB and PS-PMMA systems, for which generalized phase diagrams are constructed.

13.
ESMO Open ; 7(4): 100525, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-35777164

RESUMEN

BACKGROUND: The incidence of cutaneous melanoma is increasing in Italy, in parallel with the implementation of gene panels. Therefore, a revision of national genetic assessment criteria for hereditary melanoma may be needed. The aim of this study was to identify predictors of susceptibility variants in the largest prospective cohort of Italian high-risk melanoma cases studied to date. MATERIALS AND METHODS: From 25 Italian centers, we recruited 1044 family members and germline sequenced 940 cutaneous melanoma index cases through a shared gene panel, which included the following genes: CDKN2A, CDK4, BAP1, POT1, ACD, TERF2IP, MITF and ATM. We assessed detection rate according to familial status, region of origin, number of melanomas and presence and type of non-melanoma tumors. RESULTS: The overall detection rate was 9.47% (5.53% analyzing CDKN2A alone), ranging from 5.14% in sporadic multiple melanoma cases (spoMPM) with two cutaneous melanomas to 13.9% in familial cases with at least three affected members. Three or more cutaneous melanomas in spoMPM cases, pancreatic cancer and region of origin predicted germline status [odds ratio (OR) = 3.23, 3.15, 2.43, P < 0.05]. Conversely, age > 60 years was a negative independent predictor (OR = 0.13, P = 0.008), and was the age category with the lowest detection rate, especially for CDKN2A. Detection rate was 19% when cutaneous melanoma and pancreatic cancer clustered together. CONCLUSIONS: Gene panel doubled the detection rate given by CDKN2A alone. National genetic testing criteria may need a revision, especially regarding age cut-off (60) in the absence of strong family history, pancreatic cancer and/or a high number of cutaneous melanomas.


Asunto(s)
Melanoma , Neoplasias Pancreáticas , Neoplasias Cutáneas , Inhibidor p16 de la Quinasa Dependiente de Ciclina , Mutación de Línea Germinal , Humanos , Persona de Mediana Edad , Estudios Prospectivos , Melanoma Cutáneo Maligno , Neoplasias Pancreáticas
14.
Food Funct ; 13(15): 8313-8328, 2022 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-35842943

RESUMEN

Chili powder is a widely used spice with pungent taste, often consumed on a daily basis in several countries. Recent prospective cohort studies showed that the regular use of chili pepper improves healthspan in humans. Indeed, chili pepper fruits contain phenolic substances which are structurally similar to those that show anti-aging properties. The objective of our study was to test whether consumption of chili-supplemented food by the fruit fly, Drosophila melanogaster, would prolong lifespan and in which way this chili-supplemented food affects animal metabolism. Chili powder added to food in concentrations of 0.04%-0.12% significantly extended median lifespan in fruit fly cohorts of both genders by 9% to 13%. However, food supplemented with 3% chili powder shortened lifespan of male cohorts by 9%. Lifespan extension was accompanied by a decrease in age-independent mortality (i.e., death in early ages). The metabolic changes caused by consumption of chili-supplemented food had a pronounced dependence on gender. A characteristic of both fruit fly sexes that ate chili-supplemented food was an increased resistance to cold shock. Flies of both sexes had lower levels of hemolymph glucose when they ate food supplemented with low concentrations of chili powder, as compared with controls. However, males fed on food with 3% chili had lower levels of storage lipids and pyruvate reducing activity of lactate dehydrogenase compared with controls. Females fed on this food showed lower activities of hexokinase and pyruvate kinase, as well as lower ADP/O ratios, compared with control flies.


Asunto(s)
Capsicum , Drosophila melanogaster , Alérgenos , Animales , Capsicum/química , Femenino , Humanos , Longevidad , Masculino , Redes y Vías Metabólicas , Polvos , Especias
15.
Genes (Basel) ; 13(6)2022 06 14.
Artículo en Inglés | MEDLINE | ID: mdl-35741823

RESUMEN

Background: Hypertriglyceridemia (HTG) is one of the most common forms of lipid metabolism disorders. The leading clinical manifestations are pancreatitis, atherosclerotic vascular lesions, and the formation of eruptive xanthomas. The most severe type of HTG is primary (or hereditary) hypertriglyceridemia, linked to pathogenic genetic variants in LPL, APOC2, LMF1, and APOA5 genes. Case: We present a clinical case of severe primary hypertriglyceridemia (TG level > 55 mmol/L in a 4-year-old boy) in a consanguineous family. The disease developed due to a previously undescribed homozygous deletion in the APOA5 gene (NM_052968: c.579_592delATACGCCGAGAGCC p.Tyr194Gly*68). We also evaluate the clinical significance of a genetic variant in the LPL gene (NM_000237.2: c.106G>A (rs1801177) p.Asp36Asn), which was previously described as a polymorphism. In one family, we also present a different clinical significance even in heterozygous carriers: from hypertriglyceridemia to normotriglyceridemia. We provide evidence that this heterogeneity has developed due to polymorphism in the LPL gene, which plays the role of an additional trigger. Conclusions: The homozygous deletion of the APOA5 gene is responsible for the severe hypertriglyceridemia, and another SNP in the LPL gene worsens the course of the disease.


Asunto(s)
Hipertrigliceridemia , Pancreatitis , Apolipoproteína A-V/genética , Preescolar , Heterocigoto , Homocigoto , Humanos , Hipertrigliceridemia/genética , Hipertrigliceridemia/patología , Masculino , Pancreatitis/genética , Eliminación de Secuencia
16.
Cells ; 11(9)2022 05 03.
Artículo en Inglés | MEDLINE | ID: mdl-35563838

RESUMEN

Progress in the development of technologies for the real-time monitoring of neurotransmitter dynamics has provided researchers with effective tools for the exploration of etiology and molecular mechanisms of neuropsychiatric disorders. One of these powerful tools is fast-scan cyclic voltammetry (FSCV), a technique which has progressively been used in animal models of diverse pathological conditions associated with alterations in dopamine transmission. Indeed, for several decades FSCV studies have provided substantial insights into our understanding of the role of abnormal dopaminergic transmission in pathogenetic mechanisms of drug and alcohol addiction, Parkinson's disease, schizophrenia, etc. Here we review the applications of FSCV to research neuropsychiatric disorders with particular attention to recent technological advances.


Asunto(s)
Dopamina , Enfermedad de Parkinson , Animales , Modelos Animales , Neurotransmisores
17.
Arch Insect Biochem Physiol ; 110(4): e21893, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35388481

RESUMEN

Glyphosate-based herbicide Roundup, as the most employed herbicide used for multiple purposes in agriculture, adversely affects nontarget organisms. We tested the effects of Roundup applied at larval and adult stages. Roundup caused developmental delay and increased larvae mortality. Roundup treatment reduced hemolymph glucose and glycogen levels in adult flies of both sexes at the highest concentration tested. Sex-dependent diverse effects were found in catalase and Cu,Zn superoxide dismutase (Cu,Zn-SOD) activities. Decreased aconitase activity, contents of thiols, and lipid peroxides were found after larval Roundup exposure. Furthermore, chronic exposure to adult flies decreased appetite, body weight, and shortened lifespan. Thus, our results suggest that high concentrations of Roundup are deleterious to both larvae and adults, resulting in a shift of the metabolism and antioxidant defense system in Drosophila melanogaster.


Asunto(s)
Herbicidas , Animales , Antioxidantes/metabolismo , Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Femenino , Herbicidas/metabolismo , Herbicidas/toxicidad , Larva/metabolismo , Masculino , Estrés Oxidativo
18.
Diseases ; 10(1)2022 Jan 18.
Artículo en Inglés | MEDLINE | ID: mdl-35225859

RESUMEN

Familial hypercholesterolemia (FH) and elevated lipoprotein(a) [Lp(a)] level are the most common inherited disorders of lipid metabolism. This study evaluated the impact of high Lp(a) level on accuracy Dutch Lipid Clinic Network (DLCN) criteria of heterozygous FH diagnosis. A group of 206 individuals not receiving lipid-lowering medication with low-density lipoprotein cholesterol (LDL-C) >4.9 mmol/L was chosen from the Russian FH Registry. LDL-C corrected for Lp(a)-cholesterol was calculated as LDL-C − 0.3 × Lp(a). DLCN criteria were applied before and after adjusting LDL-C concentration. Of the 206 patients with potential FH, a total of 34 subjects (17%) were reclassified to less severe FH diagnosis, 13 subjects of them (6%) were reclassified to "unlike" FH. In accordance with Receiver Operating Characteristic curve, Lp(a) level ≥40 mg/dL was associated with FH re-diagnosing with sensitivity of 63% and specificity of 78% (area under curve = 0.7, 95% CI 0.7−0.8, p < 0.001). The reclassification was mainly observed in FH patients with Lp(a) level above 40 mg/dL, i.e., 33 (51%) with reclassified DLCN criteria points and 22 (34%) with reclassified diagnosis, compared with 21 (15%) and 15 (11%), respectively, in patients with Lp(a) level less than 40 mg/dL. Thus, LDL-C corrected for Lp(a)-cholesterol should be considered in all FH patients with Lp(a) level above 40 mg/dL for recalculating points in accordance with DLCN criteria.

19.
J Org Chem ; 86(24): 18107-18116, 2021 Dec 17.
Artículo en Inglés | MEDLINE | ID: mdl-34878276

RESUMEN

An electrochemical process of free-radical difunctionalization of vinyl arenes with N-hydroxyphthalimide resulting in vicinal dioxyphthalimides was discovered. The reaction proceeds with the use of pyridinium perchlorate and pyridine as a supporting electrolyte and a base, respectively. The present approach involves the anodic generation of stabilized phthalimide-N-oxyl (PINO) radical, which adds to the carbon-carbon double bond of vinyl arenes and recombines with the subsequently formed benzylic radical. A wide range of dioxyphthalimides were obtained in yields up to 81%.

20.
Polymers (Basel) ; 13(15)2021 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-34372115

RESUMEN

Structural and morphological features of graft polystyrene (PS) and polyethylene (PE) copolymers produced by post-radiation chemical polymerization have been investigated by methods of X-ray microanalysis, electron microscopy, DSC and wetting angles measurement. The studied samples differed in the degree of graft, iron(II) sulphate content, sizes of PE films and distribution of graft polymer over the polyolefin cross section. It is shown that in all cases sample surfaces are enriched with PS. As the content of graft PS increases, its concentration increases both in the volume and on the surface of the samples. The distinctive feature of the post-radiation graft polymerization is the stepped curves of graft polymer distribution along the matrix cross section. A probable reason for such evolution of the distribution profiles is related to both the distribution of peroxide groups throughout the sample thickness and to the change in the monomer and iron(II) salt diffusion coefficients in the graft polyolefin layer. According to the results of electron microscope investigations and copolymer wettability during graft polymerization, a heterogeneous system is formed both in the sample volume and in the surface layer. It is shown that the melting point, glass transition temperature and degree of crystallinity of the copolymer decreases with the increasing proportion of graft PS. It is suggested that during graft polymerization a process of PE crystallite decomposition (melting) and enrichment of the amorphous phase of graft polymer by fragments of PE macromolecules occurs spontaneously. The driving force of this process is the osmotic pressure exerted by the phase network of crystallites on the growing phase of the graft PS.

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