Holographic Recording Media based on Electron Donor Oligomers

For optical holographic recording by photothermoplastic technique reversible holographic media based on oligomers with hole type of conductivity are used. New carbazole containing radial tetrasubstituted silanes and germanes are described in the present work

Торакоскопия в лечении буллезной болезни легких, осложненной пневмотораксом

The authors’ treatment experience of 292 patients with spontaneous pneumothorax is presented. Results of the pleural drainage (188 patients), thoracoscopy and talc pleurodesis (43 patients), videothoracoscopic surgical treatment (61 patients) are discussed. Recurrent pneumothorax after videothoracoscopic treatment was in 1 case only and only 1 patient needed in open thoracotomy (p < 0.05). Videothoracoscopy is an accurate, safe, and reliable alternative for open thoracotomy and conservative treatment in the management of patients with spontaneous pneumothorax.Обобщен опыт авторов в лечении 292 пациентов со спонтанным пневмотораксом (СП). Сравнительному анализу подвергнуты результаты дренирования плевральной полости (188 больных), традиционной торакоскопии и индукции плевродеза (43 пациента) и применения алгоритма диагностики и лечения СП на основе видеоторакоскопии и компьютерной томографии (61 пациент). Применение предлагаемого алгоритма позволило снизить частоту рецидивов до 2,8 %, при этом показания к торакотомиям возникли у 1,7 % пациентов

Система формування клінічного мислення студентів при проведенні семінарських і практичних занять із циклу «Хірургія»

В результаті запропонованої системи при проведенні семінарських та практичних занять у студентів формується здатність комплексного аналізу клінічних ситуацій, відбувається формування у майбутніх лікарів відповідних знань, умінь, засвоєння практичних навичок, поглибленого і систематизованого підходу до можливостей нових діагностичних методів і принципів лікування.The proposed system results in the ability of students to perform complex analysis of clinical situations during the seminars and practical classes, to form the future doctors’ appropriate knowledge, skills, to master practical skills, to systematize approach to the new diagnostic methods and principles of treatment

Активні форми навчання при вивченні хірургії

Активні форми навчання, що застосовуються на кафедрі хірургії №1, дозволяють розвинути у студентів клінічне та критичне мислення, формувати досвід творчої та інноваційної діяльності, вдосконалюють компетенції, навчають працювати на випередження, що формує уміння вільно обмінюватися думками, моделювати життєві ситуації, що дозволяє підготувати висококваліфікованого лікаря.Active forms of education, which are used in the Department of Surgery №1, allow to develop clinical and critical way of thinking in students, to form experience of creative and innovative activity, to improve competences, to learn to work in advance, which forms the ability to exchange thoughts freely, to model life situations for preparing a highly qualified doctor

Anomalous structure and properties of poly (dA).poly(dT). Computer simulation of the polynucleotide structure with the spine of hydration in the minor groove.

The results of the search for low-energy conformations of poly(dA).poly(dT) and of the poly(dA).poly(dT) "complex" with the spine of hydration similar to that found by Dickerson and co-workers (Kopka, M.L., Fratini, A.V., Drew, H.R. and Dickerson, R.E. (1983) J. Mol. Biol. 163, 129-146) in the minor groove of the CGCGAATTCGCG crystals are described. It is shown that the existence of such a spine in the minor groove of poly(dA).poly(dT) is energetically favourable. Moreover, the spine of hydration makes the polynucleotide conformation similar to the poly(dA).poly(dT) structure in fibers and to the conformation of the central part of CGCGAATTCGCG in crystals; it also acquires features characteristic of the structure of poly(dA).poly(dT) and DNA oligo(dA)-tracts in solution. It is shown that the existence of the TpA step in conformations characteristic of the poly(dA).poly(dT) complex with the spine of hydration is energetically unfavourable (in contrast to the ApT step) and therefore this step should result in destabilization of the spine of hydration in the DNA minor groove. Thus, it appears that the spine of hydration as described by Dickerson and co-workers is unlikely to exist in the poly d(A-T).poly d(A-T) structure. The data obtained permit us to interpret a large body of experimental facts concerning the unusual structure and properties of poly(dA).poly(dT) and oligo(dA)-tracts in DNA both in fibers and in solution. The results provide evidence of the existence of the minor groove spine of hydration both in fibers and in solution on A/T tracts of DNA which do not contain the TpA step. The spine plays an active role in the formation of the anomalous conformation of these tracts

Alteration of the DNA double helix conformation upon incorporation of mispairs as revealed by energy computations and pathways of point mutations.

To explain biochemical and genetic data on spontaneous nucleotide replacements in nucleic acid biosynthesis all the 8 mispairs in normal tautomeric forms have been considered. Possible B-conformations of DNA fragments containing each of such mispairs incorporated between Watson-Crick pairs have been found using computations of the energy of non-bonded interactions via classical potential functions. These conformations have no reduced interatomic contacts. The values of each dihedral angle of the sugar-phosphate backbone fall within the limits of those of double-helical fragments of B-DNA in crystals. These values differ from those of the corresponding angles for the low-energy polynucleotide conformations consisting of canonical pairs by no more than 30 degrees (except for the fragment with the U:U pair for which the C4'-C3'-O-P angle differs by about 50 degrees). The difference in experimentally observed frequencies of various nucleotide replacements in DNA biosynthesis correlates with the difference in the energy of non-bonded interactions and with the extent of the sugar-phosphate backbone distortion for the fragments containing the mispairs which serve as intermediates for the replacements

Possible conformations of double-helical polynucleotides containing incorrect base pairs.

Theoretical conformational analysis using classical potential functions has shown the possibility of incorporation of nucleotide mispairs with the bases in normal tautomeric forms into the DNA double helix. Incorrect purine-pyrimidine, purine-purine and pyrimidine-pyrimidine pairs can be incorporated into the double helix existing both in A- and B-conformations. The most energy favourable conformations of fragments containing a mispair have all the dihedral angles of the sugar-phosphate backbone within the limits characteristic of double helices consisting of Watson-Crick nucleotide pairs. Incorporation of mispairs is possible practically without the appearance of reduced interatomic contacts. Mutual position of bases in the incorporated mispair does not differ much from their position at the energy minimum of the corresponding isolated base pairs. Conformational parameters of irregular regions of double-stranded polynucleotides containing G:U, I:A, I:A* (syn) and U:C pairs are presented. Distortion of the sugar-phosphate backbone is the least upon incorporation of the G:U pair. Formation of mispairs in the processes of nucleic acid biosynthesis and spontaneous mutagenesis is discussed

The structure of poly(dA):poly(dT) in a condensed state and in solution.

New X-ray and energetically optimal models of poly(dA):poly(dT) with the hydration spine in the minor groove have been compared with the NMR data in solution (Behling, R.W. and Kearns, D.R. (1986) Biochemistry 25, 3335-3346). These models have been refined to achieve a better fit with the NMR data. The obtained results suggest that the poly(dA):poly(dT) structure in a condensed state is similar to that in solution. The proposed conformations of poly(dA):poly(dT), unlike the classic B form, satisfy virtually all geometrical requirements which follow from the NMR data. Thus, the X-ray and energetically optimal poly(dA):poly(dT) structures (or those with slight modifications) can be considered as credible models of the poly(dA):poly(dT) double helix in solution. One of the features distinguishing these models from the classic B form is a narrowed minor groove