First main series of transition elements with atomic numbers from 22 to 29, found in air pollution and detected in the plants from Tajikistan areas.

According to several reports, the presence of transition metal elements in the atmosphere was associated with adverse health effects. The purpose of this investigation was to analyze the presence of transition metal particles with atomic numbers 22-29 on some medicinal plants (n = 22) from various regions of the Republic of Tajikistan and their content in the atmosphere. Samples (n = 43) of individual plant organs, such as seeds, flowers, leaves, trunks, and plant roots, were examined for their elemental composition using X-ray fluorescence analysis. Selection of particles contained in the atmosphere was carried out for 24 h/3 days by the aspiration method using fiberglass filters GF 10 in an apparatus installed at an altitude of 864 m on the periphery of the capital. For the analysis of plant samples, measurements were carried out on a SPECTROSCAN MAX-G wave-dispersive X-ray fluorescence spectrometer. For samples containing filtered atmosphere elements, a high-resolution PANanalytical Epsilon 5 high-resolution energy-dispersive spectrometer was used. Eight transition elements from the 1st main series of metals with atomic numbers 22-29, such as titanium, vanadium, chromium, manganese, iron, cobalt nickel, and copper, were found in plant organs, as well as in the atmosphere samples. Our results showed that the distribution of metals on plants varied depending on plants and their organs. We did not find any correlation between the region of plant collection and their absorption of metal elements. The distribution of metals varied in various plant organs. In the atmosphere samples, we found all the metals that were found in plants. In conclusion, medicinal plants can adsorb and accumulate some harmful chemical elements in their organs, are involved in the recirculation of these metals, and contribute air pollution.

Characteristics of BENZOPYRAN Laser Dyes in Annealed Silica XEROGEL.

The spectroscopic and laser characteristics of two benzopyrane derivatives for 600-670 nm spectrum region of lasing in preliminarily annealed silica xerogel matrices in non-selective cavity under laser pumping at 551 nm have been measured and analysed. The influence of molecular structure of the dyes on their non-radiating losses has been revealed. The specific output laser energy of the studied matrices was approximately equal to the ones for corresponding methanol solutions under the same pumping conditions. The laser spectra of the matrices were displaced to the red region from the fluorescence maximum by about 1000-1500 cm-1 in a nonselective cavity. Such spectral displacement may improve the characteristics of biosensors made on the basis of these matrices because it shifts their emission spectrum to the range of deeper penetration into biological tissues.

Enantioselective cellular uptake of chiral semiconductor nanocrystals.

The influence of the chirality of semiconductor nanocrystals, CdSe/ZnS quantum dots (QDs) capped with L- and D-cysteine, on the efficiency of their uptake by living Ehrlich Ascite carcinoma cells is studied by spectral- and time-resolved fluorescence microspectroscopy. We report an evident enantioselective process where cellular uptake of the L-Cys QDs is almost twice as effective as that of the D-Cys QDs. This finding paves the way for the creation of novel approaches to control the biological properties and behavior of nanomaterials in living cells.

Chlorin e6-ZnSe/ZnS quantum dots based system as reagent for photodynamic therapy.

Stable water-soluble complexes of Cd-free ZnSe/ZnS quantum dots (QDs) and chlorin e6 complexes have been prepared. These complexes have shown approximately 50% intracomplex fluorescence resonance energy transfer from QDs to chlorin e6. The photodynamic therapy (PDT) test of the complexes against the Erlich acsite carcinoma cell culture demonstrated a two-fold enhancement of the cancer cell photodynamic destruction as compared to that of free chlorin e6 molecules. It was shown that the PDT effect was significantly increased due to two factors: the efficient QD-chlorin e6 photoexcitation energy transfer and the improvement of cellular uptake of the photosensitizer in the presence of ZnSe/ZnS QDs.

[Focal nodular liver hyperplasia].

It was evaluated the frequency of focal nodular liver hyperplasia and treatment resultsin 1425 patients for the last 17 years in 2 time period. The own experience and literature data were used. First this disease was considered as very rare liver tumor because of underdeveloped diagnostics. Tumor detection was the indication for laparotomy. In some patients removal of the tumor was not performed if intraoperativebiopsy has shown tumor benign. The indication for dynamic observation and surgical treatment were identified with increasing number of patients, diagnostics improvement, and analysis of immediate and long-term results. The operation provides persistentcure.

Reversible photoluminescence quenching of CdSe/ZnS quantum dots embedded in porous glass by ammonia vapor.

The photoluminescence response of semiconductor CdSe/ZnS quantum dots embedded in a borosilicate porous glass matrix to exposure to ammonia vapor is investigated. The formation of surface complexes on the quantum dots results in quenching of the photoluminescence and a shortening of the luminescence decay time. The process is reversible, desorption of ammonia molecules from the quantum dot surface causes the photoluminescence to recover. The sensitivity of the quantum dot luminescence intensity and decay time to the interaction time and the reversibility of the photoluminescence changes make the CdSe/ZnS quantum dots in porous glass system a candidate for use as an optical sensor of ammonia.

Direct mass measurements of 19B, 22C, 29F, 31Ne, 34Na and other light exotic nuclei.

We report on direct time-of-flight based mass measurements of 16 light neutron-rich nuclei. These include the first determination of the masses of the Borromean drip-line nuclei (19)B, (22)C, and (29)F as well as that of (34)Na. In addition, the most precise determinations to date for (23)N and (31)Ne are reported. Coupled with recent interaction cross-section measurements, the present results support the occurrence of a two-neutron halo in (22)C, with a dominant ν2s(1/2)(2) configuration, and a single-neutron halo in (31)Ne with the valence neutron occupying predominantly the 2p(3/2) orbital. Despite a very low two-neutron separation energy the development of a halo in (19)B is hindered by the 1d(5/2)(2) character of the valence neutrons.

Aspects of "antigen-antibody" interaction of chicken infectious bronchitis virus determined by surface plasmon resonance.

Authors performed investigation on "antigen-antibody" interaction of chicken infectious bronchitis coronavirus (IBV) by a method based on the surface plasmon resonance (SPR). Presence of space-size effect related to a difference between antigen and antibody particle sizes has been theoretically grounded and experimentally proven. Herewith, the difference between responses of the SPR-sensor to specific and non-specific interactions is considerably less (up to 6.3 times) than the expected one (8 - 11 times). An impact of functionalization of sensor's sensitive element surface, as well as acidity of buffer solution on the activity of antigen-antibody interaction was studied here. The difference between sensor's responses to specific and non-specific interactions increased two-fold from 200 to 432ang sec due to this treatment. When changing the acidity of analyzed solution from pH7.3 to pH6.8, the corresponding difference between sensor's responses increased by 6.3 times from 194 up to 1235ang.sec. Thus, an impact of space-size effect on interaction between IBV antigen and specific antibody can be considerably (almost in 3 times) decreased by reducing the acidity of used buffer solution. The results of our investigation can be successfully applied to develop new methods for detection of pathogens and specific antibodies using SPR.

Track membranes with embedded semiconductor nanocrystals: structural and optical examinations.

We studied the optical properties of poly(ethylene terephthalate) ion track membranes of 1.5, 0.5 and 0.05 µm pores impregnated with luminescent semiconductor CdSe/ZnS nanocrystals of different diameters (2.5 and 5 nm). The nanocrystals were embedded from their colloidal solutions in toluene by the immersion of a membrane in a colloidal solution. Localization of quasi-isolated weakly interacting CdSe/ZnS nanocrystals in a loosened layer on the track pore wall surface along with the existence of empty pores was demonstrated. We observed also the spatial separation of nanocrystals of 2.5 and 5 nm in size along the 50 nm pores.

Chitosan nanocomposites with CdSe/ZnS quantum dots and porphyrin.

Water-soluble nanocomposites based on CdSe/ZnS quantum dots (QDs) and hydrophobic tetraphenylporphyrin (TPP) molecules passivated by chitosan (CS) have been formed. Magnetic circular dichroism (MCD) spectra evidence TPP presence in both monomeric and agglomerated forms in the nanocomposites. The nanocomposites demonstrate more pronounced singlet oxygen generation compared to free TPP in CS at the same concentration due to the intracomplex Förster resonance energy transfer (FRET) with a 45% average efficiency.

[Problems and prospects of non-invasive screening for colorectal cancer].

High prevalence of colorectal cancer makes it a most serious socio-medical problem. Hence, the necessity of overall screening for prodromal changes and malignant neoplasms at the early stages of the disease. Despite a variety of efficacious instrumental diagnostic tools, the development of non-invasive screening techniques based on recent progress in understanding molecular mechanisms of carcinogenesis remains a highly topical issue. A pathogenetic model of colorectal cancer and pathophysiological basis of screening for colonic neoplasms are considered with the emphasis on the detection of tumour cells in faeces and their DNA carrying mutations in suppressor genes and oncogenes. Results of the studies with the use of one or several DNA oncomarkers are analysed in the context of their value for the diagnosis of colorectal neoplasms. High sensitivity and specificity of these methods make them very promising for application to the screening for colorectal cancer.

[Ligature fixation of floating ribs at closed injury of chest].

Original devices (pericostal needle for passage of ligatures around ribs and sternum, and breast splint for ligature fixation of floating ribs) have been produced and patented. This method has been clinically approved at 111 patients with multiple fragmentary fractures of ribs. These devices made the surgical procedures easier and were effective at the treatment of severe closed injury of chest. Frame of chest is restored, severe respiratory failure is eliminated. In one day lung vital capacity increases in 1.5-2 times, blood oxygenation - on 12%. Lethality has been reduced in 3 times compared with traditional methods of floating ribs traction. Forty-one of 43 severe patients have been successfully cured.

[Expanded D2 lymphodissection in combined treatment of gastric cancer: unification of treatment approaches].

The authors present an analysis of results of using D2 operations in combined treatment of gastric cancer. Such volumes of operations combined with preoperative irradiation are not followed by greater number of complications and lethality. The incidence of progressing in terms more than a year proved to be considerably lower in the group of patients with combined treatment with D2 lymphodissection than in the groups without lymphodissection and preoperative radiation therapy.

[Experimental study of root dentine permeability for medicines].

The use of contemporary endodontic methods of treatment do not always result in elimination of chronic nodus in periodontum, and filled teeth often remain potential noduses of infection, notwithstanding the impression of clinical and roentgenological wellness. Study of permeability of tooth root dentine under effect of medicines and microorganisms was done by means of introduction of colorant into the canal by iodine-electrophoresis method, observation of permeability of medicine from the canal through hard tissues of tooth and inhibition of growth of microorganisms in nutrient medium. It has been found out that the maximum permeability of tooth root dentine was observed in the cervical third of the root.

Ganglionic neuronal mechanisms involved in circulatory control system.

Intracellular tonic activity and responses to orthodromic stimuli were recorded from the neurones of rabbit superior cervical ganglion and compared with those recorded from the nerves containing pre- and postganglionic nerve fibres, with the use of a coherent recording technique. It was found that: (1) firing of each ganglion neurone is triggered by two presynaptic inputs, single and multiple, formed by a single preganglionic nerve fibre whose discharges evoke the postsynaptic spikes correlated with cardiac rhythm, and by a few converging preganglionic nerve fibres which evoke the postsynaptic spikes, either correlated with cardiac rhythm or irregular, only if two or more of them discharge together, correspondingly; (2) about 240 neurones of the ganglion, on the average, fire synchronously during their tonic activity, being driven by only three preganglionic nerve fibres; (3) only about 9% of a "neural unit", the number of the ganglion neurones receiving innervation from the same preganglionic nerve fibre, are discharged during their tonic activity through a single input, while the rest of neurones are either discharged through a multiple input (17%), or generate only the excitatory postsynaptic potentials subthreshold for spike generation (73%). The results obtained suggest that the ganglionic neuronal mechanisms responsible for vasomotor control involve much more complex ganglionic integrative processes than it has been commonly thought.

[Study of primary photoprocesses in photosystem II of Chlamydomonas mutant strains by hole-burning spectroscopy]. / Issledovanie pervichnykh fotoprotsessov v fotosisteme 2 mutantov khlamidomonady metodom spektroskopii vyzhiganiia provalov.

The method of hole-burning in absorption spectra at helium temperatures has been applied to the study of primary photoprocesses in photosystem II (PS2) of Chlamydomonas reinhardii mutant strains 420/7 and N-154. The former is enriched in PS2 reaction centers (the chlorophyll a/P680 ratio is about of 50--70) and the latter presumably lacks the pheophytin molecule which is the primary electron acceptor in PS2. For the strain 420/7 samples with ferricyanide addition two types of holes have been observed differing in their width and spectral region of burning. One type could be burned in the region of 678--682 nm (P680 is responsible for burning) and another one -- in the region of 682--688 nm (pheophytin is responsible). The excited states relaxation times evaluated from the hole widths are 3,8 +/- 0,8 ps for P680 and 9,8 +/- 1.5 ps for pheophytin. The new mechanism of PS2 operating has been proposed in which photoexcited phenophytin molecule functions as a primary electron donor. In the case of N-154 strain the only type of holes has been observed for which P680 is responsible. The excited state relaxation time of the latter evaluated from the hole width is 10 +/- 2 ps.

[Spectroscopic study of "hole burning" of the initial photoprocesses in photosystem I of mutant strain Chlamydomonas reinhardii 516-3a enriched with P700 reaction centers]. / Issledovanie metodom spektroskopii "vyzhiganiia provalov" pervichnykh fotoprotsessov v fotosisteme 1 mutantnogo shtamma Chlamydomonas reinhardii 516-3a, obogashchennogo reaktsionnymi tsentrami P700.

The effect of "hole burning" in absorption spectrum upon monochromatic illumination at 4.2 degrees K has been investigated on the Chlamydomonas reinhardii mutant strain 516-3a which possesses the chlorophyll a/P700 ratio of about 25. This effect has been earlier discovered for the wild type strain of Chlorella. In the strain 516-3a two types of holes differing in width and in shape have been observed. For their assignment the maximal (saturated) holewidth has been studied as a function of the burning wavelength. It has been shown that for the holes of one type photooxidation of P700 is responsible. The other type of holes is caused by electrochromic transition shift of another component of the reaction centre with the absorption maximum at 693 nm. Using measured holewidths it has been estimated that the lifetime of P700 excited state is not less than 50 ps and that the excited state lifetime of the component responsible for the other type of holes is 8.6 ps. The latter, in assumption that it is limited by energy transfer between two components under consideration, gives a distance of 20 A between them. Possible reasons of disagreement between obtained P700* lifetime and considerably shorter times attributed earlier to the primary electron phototransfer in photosystem I on the basis of picosecond studies are discussed.

["Burning" of troughs in the low-temperature absorption spectra of a strain of Chlamydomonas reinhardii enriched by P700]. / Vyzhiganie provalov v nizkotemperaturnykh spektrakh pogloshcheniia shtamma Chlamydomonas reinhardii, imeiushchego obogashchenie po P700.

Spectral and photochemical parameters were described of the mutant strain of Chlamydomonas reinhardii 516--3a, in which the ratio chlorophyll a/P700 is about 20. Experiments were carried out with this strain for investigating earlier observed for Chlorella effect of burning out of deeps in absorption spectra at 4.2K resulting from irradiation with monochromatic light of the wavelength 698 nm. Arguments are presented in favour of the assumption that phototransformation of P700 is responsible for the formation of deeps. It has been found from the width of the deeps that the lifetime of the excited states of the centres responsible for the formation of deeps is between 16 ps and 65 ps.