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1.
Chaos ; 30(11): 111104, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33261344

RESUMO

We study active matter systems where the orientational dynamics of underlying self-propelled particles obey second-order equations. By primarily concentrating on a spatially homogeneous setup for particle distribution, our analysis combines theories of active matter and oscillatory networks. For such systems, we analyze the appearance of solitary states via a homoclinic bifurcation as a mechanism of the frequency clustering. By introducing noise, we establish a stochastic version of solitary states and derive the mean-field limit described by a partial differential equation for a one-particle probability density function, which one might call the continuum Kuramoto model with inertia and noise. By studying this limit, we establish second-order phase transitions between polar order and disorder. The combination of both analytical and numerical approaches in our study demonstrates an excellent qualitative agreement between mean-field and finite-size models.

2.
Soc Psychiatry Psychiatr Epidemiol ; 51(5): 757-65, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-26873615

RESUMO

PURPOSE: Family stigma constitutes a major problem in schizophrenia worldwide. Data on first-hand experience of stigma in families is necessary for planning and implementing interventions to reduce its burden. The aim of the study was to investigate the experience of stigma among relatives of persons with schizophrenia in Belarus. METHODS: Qualitative research methods, such as the thematic analysis of in-depth semi-structured interviews with 20 relatives of people diagnosed with schizophrenia, were used. Experience of discrimination, strategies used to cope with it, and requests for interventions were investigated. RESULTS: The most salient themes in experience of stigma in the private domain of life elicited in the narratives included anticipated stigma and dissolution of families. The experience of stigma was associated with burdensome feelings of guilt, tiredness and loneliness, together with fear and anxiety due to uncertainty in the future and sorrow because of frustrated hopes in past. Analysis of the strategies used to overcome the difficulties revealed concealment and "life behind closed doors", avoidance of the rest of the family, taking full responsibility and sacrificing one's personal life. CONCLUSION: To reduce the burden of stigma in the private life of the family members of people living with schizophrenia in Belarus, important steps should be taken to promote the empowerment of families including: reforming mental health services; provision of better access to information; family support services, community care; development of family organisations; assistance in communication, re-socialisation and independent living for people diagnosed with schizophrenia.


Assuntos
Cuidadores/psicologia , Países em Desenvolvimento , Esquizofrenia/diagnóstico , Psicologia do Esquizofrênico , Estigma Social , Adaptação Psicológica , Adulto , Efeitos Psicossociais da Doença , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Preconceito , Pesquisa Qualitativa , República de Belarus , Esquizofrenia/terapia , Isolamento Social
3.
J Photochem Photobiol B ; 42(3): 181-90, 1998 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9595707

RESUMO

Interaction between molecular oxygen and the cationic free-base 5,10,15,20-tetrakis (4-N-methylpyridyl) porphyrin (H2TMpyP4+) complexed with [poly (dA-dT)]2, [poly (dG-dC)]2 and calf thymus DNA, has been monitored in air-saturated heavy water solutions through porphyrin triplet-triplet absorption and singlet oxygen luminescence. Three different rate constants of porphyrin triplet state quenching have been found which correspond to different accessibilities of molecular oxygen to porphyrins embedded in the duplexes. The longest triplet state lifetime (30 microseconds), found for porphyrin bound to [poly (dG-dC)]2, corresponds to molecules well protected from oxygen. This supports the hypothesis of an intercalative binding mode of the porphyrin between GC base-pairs ('type A' sites). The fraction fT delta of the porphyrin triplet states quenched by molecular oxygen with singlet oxygen generation, is unity. In [poly (dA-dT)]2-porphyrin complexes, two sites ('type B' and 'C' sites of interaction) are involved, yielding very different triplet state lifetimes (5.5 microseconds and 20.5 microseconds) and efficiencies of singlet oxygen generation (fT delta = 0.50 and 0.82). The fT delta decreases can likely be explained in terms of competition between energy and electron transfer from the porphyrin excited triplet state to molecular oxygen. All three types (A, B and C) of interaction sites can be expected in porphyrin-DNA complexes.


Assuntos
DNA/metabolismo , Oxigênio/metabolismo , Poli dA-dT/metabolismo , Polidesoxirribonucleotídeos/metabolismo , Porfirinas/metabolismo , Absorção , Cátions , Luz , Medições Luminescentes , Fármacos Fotossensibilizantes , Soluções
4.
Biofizika ; 41(3): 606-12, 1996.
Artigo em Russo | MEDLINE | ID: mdl-8924460

RESUMO

The processes of the proton concentration effect on the oxygen binding with triliganded human hemoglobin Hb(O2)3 have been studied by time resolved absorption spectroscopy. The pH-dependencies analysis carried out has shown that R-state alkaline Bohr effect was formed by two amino acid residues with pK = 7.3 +/- 0.1 and 9.1 +/- 0.1. It has been shown that oxygen affinity decrease at pH values above 8.5 could be caused by alpha 140-Tyr and beta 145-Tyr. The entrance and exit into/from the globin matrix is controlled by the same amino acid residues. On the strength of the experimental data the dynamics nature of the R-state alkaline Bohr effect has been proved.


Assuntos
Hemoglobinas/química , Oxigênio/química , Humanos , Concentração de Íons de Hidrogênio , Ligantes , Análise Espectral
5.
Biofizika ; 46(4): 601-6, 2001.
Artigo em Russo | MEDLINE | ID: mdl-11558368

RESUMO

The effect of ethanol on the oxygenation of hemoglobin was studied by kinetic absorption spectroscopy. It was found that the efficiency of oxygen geminate rebinding decreased upon ethanol addition. At ethanol concentrations up to 4.5 M, its influence on the structure and functional properties of the hemoglobin molecule is determined by changes in the bulk dielectric constant of solution. The decrease in the rate constant of the bimolecular stage of rebinding k'4 was caused by an increase in the viscosity of solution, with k'4 being approximately 1/eta 0.5. Upon oxidation of hemoglobin to hemichrome initiated by ethanol, dramatic conformational changes in the region of the heme pocket took place. They lead to a more than twofold increase in the efficiency of exit of oxygen molecules from the protein matrix to the solution after photodissociation.


Assuntos
Etanol/química , Hemoglobinas/química , Condutividade Elétrica , Humanos , Luz , Oxirredução , Oxigênio/química , Oxiemoglobinas/química , Solventes , Análise Espectral/métodos
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