[The influence of long-term retinal protective therapy on glaucoma progression according to structural and functional tests]. / Vliyanie dlitel'noi retinoprotektornoi terapii na progressirovanie glaukomy po dannym strukturno-funktsional'nykh issledovanii.

PURPOSE: To evaluate the influence of prolonged neuroprotective therapy on disease progression in patients with primary open-angle glaucoma (POAG) with compensated intraocular pressure (IOP). MATERIAL AND METHODS: The study included 147 patients with stages I-II POAG (249 eyes) who were randomized into the main (69 patients, 119 eyes) and control groups (78 patients, 130 eyes). Patients of the main group underwent retinalamin treatment course every 6 months. Patients were examined before enrolling and then every 3 months during the 24-months follow-up including optical coherence tomography (OCT; RNFL - retinal nerve fiber layer, NRR - neuroretinal rim, GCL - ganglion cell layer) and static perimetry (MD - mean deviation, PSD - pattern standard deviation). RESULTS: Visual acuity and refraction did not change in either group (p>0.05). IOP increased in the control group (p=0.033). There was no difference between the groups by the 24th month (p=0.87). No MD changes were noted in the main (p=0.45) and control groups (p=0.27). PSD changed in the main (4.84±3.21 and 6.01±2.584 dB in the beginning and the end, respectively, p=0.0004) and the control groups (3.46±2.23 and 5.86±2.26 dB, respectively; p<0.0001). The groups differed in MD and PSD initially (p=0.15; p=0.02) and became equal by the end (p=0.59; p=0.53). RNFL did not change significantly in the main group (p=0.078) and decreased from 83.5±22.47 to 76.7±20.7 µm in the control group (p=0.001); no differences between the groups were noted in the beginning (p=0.276) or in the end of the study (p=0.524). NRR increased in the main group from 222±88.94 to 231±99.3 (p=0.012), and decreased in the control group from 248±87.09 to 234±96.2 (p=0.0006); no differences were found between groups in the beginning or in the end of the study (p=0.109; p=0.909). GCL thickness did not change either in the main, or in the control group (p=0.211; p=0.16), with no difference between the group noted in the beginning or the end of the study (p=0.44; p=0.51). CONCLUSION: Regular treatment with retinalamin arrests the development of glaucomatous optic neuropathy. Longer-term research is required to study its influence on the visual function and the quality of life.

[Structural and functional changes in the retina of patients with primary open-angle glaucoma and compensated intraocular pressure while undergoing retinoprotective therapy]. / Strukturno-funktsional'nye izmeneniia setchatki u patsientov s pervichnoi otkrytougol'noi glaukomoi pri kompensirovannom vnutriglaznom davlenii na fone retinoprotektornoi terapii.

PURPOSE: To evaluate the efficacy and safety of intramuscular Retinalamin for retinoprotection in patients with open-angle glaucoma and normalized intraocular pressure (IOP). MATERIAL AND METHODS: The study included 180 patients (355 eyes) randomized into the main (n=90) and control groups (n=90). The patients of the main group received intramuscular Retinalamin injections; the course was repeated 6 months later. Patient examination was performed at 1, 3, 6, 7, 9 and 12 months. RESULTS: Vision acuity did not change in the main group after the treatment courses (p=0.3732, p=0.6862), nor in the control group (p=0.7751). IOP didn't have significant changes during the whole course of the study neither in the main group (p=0.7632), nor in the control group (p=0.3921). MD index in the main group has increased from -5.52±2.76 to -4.82±2.73 dB (measurements from 6 visits: p=0.0391, p=0.0201, p=0.0302, p=0.3708, p=0.0151, p=0.0353). Control group showed negative MD trend (from -3.51±1.84 to -4.60±2.61 dB; p=0.0012). PSD index has changed from 4.63±1.60 to 4.05±1.43 dB (p=0.0081) in the main group, and from 3.73±1.19 to 4.29±1.53 dB (p=0.0027) in the control group. Average thickness of retinal nerve fiber layer (RNFL) and the volume of neuroretinal rim were stable in both the main (p=0.8039, p=0.9005) and the control groups (p=0.7448, p=0.9620). Ganglion cell complex (GCC) thickness remained stable in the main group (p=0.0377), but has decreased in the control group (p=0.0250). P50 amplitude and latency were stable in the main group (6.54±2.61-6.53±2.64 µV, p=0.0479; 48.39±3.69-50.86±4.09 ms, p=0.0271), while in the control group P50 amplitude has decreased (p=0,0031) and the latency has increased (p=0,0194). In the main group, N95 amplitude has stabilized (p=0.0141) with worsened latency (p=0.0492). N95 amplitude in the control group has worsened (p=0.0195), while latency has stabilized (p=0.3401). CONCLUSION: Systemic use of Retinalamin has significant retinoprotective effect confirmed by the dynamics of morphological and functional parameters in patients with POAG and IOP compensation.

[Structural and functional changes in the retinal layers in patients with primary glaucoma and possible means of retinoprotection]. / Strukturno-funktsional'nye izmeneniia sloev setchatki pri pervichnoi glaukome i vozmozhnye puti retinoprotektsii.

Glaucoma is one of the most severe forms of ophthalmic pathology which can lead to low vision and blindness. Therapy aimed only at reducing intraocular pressure (IOP) may be insufficient in patients with this disease. PURPOSE: To study the structural and functional changes occurring in the retina and the effect of peptide bioregulator on the state of various retinal layers in patients with primary open-angle glaucoma (POAG). MATERIAL AND METHODS: The study included 62 patients (123 eyes) with POAG. The control group consisted of 25 people (50 eyes) of the same age. After the initial examination, patients of the glaucomatous group were divided into two equal subgroups. Patients of the first subgroup received 10 intramuscular injections of the peptide bioregulator; in the second subgroup, patients did not receive any retinoprotective therapy. The state of the visual analyzer was assessed using spectral optical coherence tomography (SOKT), electrophysiological research methods (ERG, PERG, flicker ERG), photostress test. RESULTS: Patients with POAG were found to have current and developing changes in the thickness and the configuration of various layers of the retina in the macular area as the disease progresses - particularly, in the nerve fiber layer (p=0.02), ganglion cells (p=0.002), inner nuclear layer (p=0.003) and the layer of pigment epithelium (p=0.049). Electrophysiological research methods helped reveal statistically significant changes in the functional parameters reflecting the generation and conduction of nerve impulses in retinal layers in patients with glaucoma. The patients undergoing peptide bioregulator therapy showed statistically significant positive changes in the state of ganglion cells observed as a decrease in the latency of the PERG N-95 wave (p=0.002) and stabilization of the structural indicators of SOCT (RNFL peripapillary zone). CONCLUSION: Patients with POAG exhibit progressive decrease in the thickness of not only the inner, but also the outer layers of the retinal macular area. According to objective structural and functional criteria, retinoprotective therapy leads to stabilization of the glaucomatous process.

Metal-passivated PbS nanoparticles: fabrication and characterization.

Organic-shell-free PbS nanoparticles have been produced in the size range relevant for quantum-dot solar cells (QDSCs) by a vapor aggregation method involving magnetron reactive sputtering. This method creates a beam of free 5-10 nm particles in a vacuum. The dimensions of the particles were estimated after their deposition on a substrate by imaging them using ex situ SEM and HRTEM electron microscopy. The particle structure and chemical composition could be deduced "on the fly", prior to deposition, using X-ray photoelectron spectroscopy (XPS) with tunable synchrotron radiation. Our XPS results suggest that under certain conditions it is possible to fabricate particles with a semiconductor core and 1 to 2 monolayer shells of metallic lead. For this case the absolute energy of the highest occupied molecular orbital (HOMO) in PbS has been determined to be (5.0 ± 0.5) eV below the vacuum level. For such particles deposited on a substrate HRTEM has confirmed the XPS-based conclusions on the crystalline PbS structure of the semiconductor core. Absorption spectroscopy on the deposited film has given a value of ∼1 eV for the lowest exciton. Together with the valence XPS results this has allowed us to reconstruct the energy level scheme of the particles. The results obtained are discussed in the context of the properties of PbS QDSCs.

[The concentration of lactate in amniotic fluid in delivery under physiological course of pregnancy].

The study was carried out to establish admissible range of concentrations of lactate using standard biochemical method in amniotic fluid at first period of delivery under physiologically progressing pregnancy. The sampling included 44 women examined during first period of urgent delivery. The samples of amniotic fluid were taken during the first period of delivery using vaginal amnitomy. The concentration of lactate in samples of amniotic fluid was established using enzymatic amperometric technique. The reference values of concentration of lactate were established in the following admissible limits: 4.4-9.4 mmol per l; ratio lactate/creatinine - 17.7-79.4; ratio lactate/protein - 0.044-0.692. The admissible range of concentration of lactate and ratio lactate/creatinine and lactate/protein in amniotic fluid at first period of delivery under physiologically progressing pregnancy was established.

Photon upconversion in degenerately sulfur doped InP nanowires.

Radiative recombination in degenerately n-doped InP nanowires is studied for excitation above and below the Fermi energy of the electron gas, using photoluminescence. Laser-induced electron heating is observed, which allows absorption below the Fermi energy. We observe photon upconversion where photo-excited holes recombine with high |k| electrons. This can be attributed to hole scattering to high |k|-values, and the temperature dependence of this process is measured. We show that hole relaxation via phonon scattering can be observed in continuous wave excitation luminescence measurements.

Visualizing charge separation in bulk heterojunction organic solar cells.

Solar cells based on conjugated polymer and fullerene blends have been developed as a low-cost alternative to silicon. For efficient solar cells, electron-hole pairs must separate into free mobile charges that can be extracted in high yield. We still lack good understanding of how, why and when carriers separate against the Coulomb attraction. Here we visualize the charge separation process in bulk heterojunction solar cells by directly measuring charge carrier drift in a polymer:fullerene blend with ultrafast time resolution. We show that initially only closely separated (<1 nm) charge pairs are created and they separate by several nanometres during the first several picoseconds. Charge pairs overcome Coulomb attraction and form free carriers on a subnanosecond time scale. Numerical simulations complementing the experimental data show that fast three-dimensional charge diffusion within an energetically disordered medium, increasing the entropy of the system, is sufficient to drive the charge separation process.

Influence of the electron-cation interaction on electron mobility in dye-sensitized ZnO and TiO2 nanocrystals: a study using ultrafast terahertz spectroscopy.

Charge transport and recombination in nanostructured semiconductors are poorly understood key processes in dye-sensitized solar cells. We have employed time-resolved spectroscopies in the terahertz and visible spectral regions supplemented with Monte Carlo simulations to obtain unique information on these processes. Our results show that charge transport in the active solar cell material can be very different from that in nonsensitized semiconductors, due to strong electrostatic interaction between injected electrons and dye cations at the surface of the semiconductor nanoparticle. For ZnO, this leads to formation of an electron-cation complex which causes fast charge recombination and dramatically decreases the electron mobility even after the dissociation of the complex. Sensitized TiO2 does not suffer from this problem due to its high permittivity efficiently screening the charges.

Probing the strength of the system-bath interaction by three-pulse photon echoes.

We explore how the width of the three-pulse photon echo signal at long population times can be used to determine the strength of the system-bath interaction. Using simulation with finite pulses we show that a simple relation exist between the width of the echo signal, the coupling strength, and the pulse autocorrelation. The derived model is applied to Rhodamine 6G in alcoholic solution, a paradigm system for the study of solvation dynamics, and the results are compared to conventional methods. The independently determined coupling strength forms the basis for a computationally inexpensive route to determine the entire spectral density, the key parameter when considering system-bath interactions. Our method allows us to accurately estimate the relative amplitude of fast and slow components in the correlation function using only impulsive limit simulations. We show that the peak shift significantly overestimates the amplitude of the fastest decay component for our experimental data. Changing solvent from methanol to 1-hexanol we observe a narrowing of the width of the echo profile. The changes in the echo width allow us to estimate the changes of the coupling strength in various solvents.

Exciton diffusion and relaxation in methyl-substituted polyparaphenylene polymer films.

Exciton diffusion in ladder-type methyl-substituted polyparaphenylene film and solution was investigated by means of femtosecond pump-probe spectroscopy using a combined approach, analyzing exciton-exciton annihilation, and transient absorption depolarization properties. We show that the different views on the exciton dynamics offered by anisotropy decay and annihilation are required in order to obtain a correct picture of the energy transfer dynamics. Comparison of the exciton diffusion coefficient and exciton diffusion radius obtained for polymer film with the two techniques reveals that there is substantial short-range order in the film. Also in isolated chains there is considerable amount of order, as revealed from only partial anisotropy decay, which shows that only a small fraction of the excitons move to differently oriented polymer segments. It is further concluded that interchain energy transfer is faster than intrachain transfer, mainly as a result of shorter interchain distances between chromophoric units.

Comparison of the effects of visible femtosecond laser pulses and continuous wave laser radiation of low average intensity on the clonogenicity of Escherichia coli.

To evaluate the contribution of local pulsed heating of light-absorbing microregions to biochemical activity, irradiation of Escherichia coli was carried out using femtosecond laser pulses (lambda = 620 nm, tau p = 3 x 10(-13) S, fp = 0.5 Hz, Ep = 1.1 x 10(-3) J cm-2, Iav = 5.5 x 10(-4) W cm-2, Ip = 10(9) W cm-2) and continuous wave (CW) laser radiation (lambda = 632.8 nm, I = 1.3 W cm-2). The irradiation dose required to produce a similar biological effect (a 160%-190% increase in the clonogenic activity of the irradiated cells compared with the non-irradiated controls) is a factor of about 10(3) lower for pulsed radiation than for CW radiation (3.3 X 10(-1) and 7.8 X 10(2) J cm-2 respectively). The minimum size of the microregions transiently heated on irradiation with femtosecond laser pulses is estimated to be about 10 A, which corresponds to the size of the chromophores of hypothetical primary photoacceptors--respiratory chain components.

Peculiarities of the B to A transition of the lambda phage regulatory site OR3 and of its fragment.

Conformations of the synthetic deoxyoligonucleotide 17 base pairs long, which is an OR3 operator of lambda phage, and of its 9-b.p. fragment were studied by the circular dichroism method (CD). The regions of stability of the double-stranded state were determined for these duplexes. A comparison of the CD spectra for these oligonucleotides with the CD for a lengthy DNA showed the conformation of these short DNA pieces to belong to the B-family. A cooperative change in the CD spectra is observed in trifluoroethanol (TFE) solutions at a TFE concentration specific for each oligonucleotide, which is supposed to stem from a B to A transition. The length of the fragment was found to affect the ability for the B-A transition. The transition into the A form is hindered by 13% TFE for the short 9-nucleotide in comparison with the 17-nucleotide. We suggest that this is due to the B form stabilization by terminal base pairs (B-phility of the ends).