Expected resolution limits of x-ray free-electron laser single-particle imaging for realistic source and detector properties

The unprecedented intensity of x-ray free-electron laser sources has enabled single-particle x-ray diffraction imaging (SPI) of various biological specimens in both two-dimensional projection and three dimensions (3D). The potential of studying protein dynamics in their native conditions, without crystallization or chemical staining, has encouraged researchers to aim for increasingly higher resolutions with this technique. The currently achievable resolution of SPI is limited to the sub-10 nanometer range, mainly due to background effects, such as instrumental noise and parasitic scattering from the carrier gas used for sample delivery. Recent theoretical studies have quantified the effects of x-ray pulse parameters, as well as the required number of diffraction patterns to achieve a certain resolution, in a 3D reconstruction, although the effects of detector noise and the random particle orientation in each diffraction snapshot were not taken into account. In this work, we show these shortcomings and address limitations on achievable image resolution imposed by the adaptive gain integrating pixel detector noise.

A versatile liquid-jet setup for the European XFEL

The SPB/SFX instrument of the European XFEL provides unique possibilities for high-throughput serial femtosecond crystallography. This publication presents the liquid-jet sample delivery setup of this instrument. The setup is compatible with state-of-the-art gas dynamic virtual nozzle systems as well as high-viscosity extruders and provides space and flexibility for other liquid injection devices and future upgrades. The liquid jets are confined in a differentially pumped catcher assembly and can be replaced within a couple of minutes through a load-lock. A two-microscope imaging system allows visual control of the jets from two perspectives.

Femtosecond phase-transition in hard x-ray excited bismuth

The evolution of bismuth crystal structure upon excitation of its A_1g phonon has been intensely studied with short pulse optical lasers. Here we present the first-time observation of a hard x-ray induced ultrafast phase transition in a bismuth single crystal at high intensities (~10¹⁴ W/cm²). The lattice evolution was followed using a recently demonstrated x-ray single-shot probing setup. The time evolution of the (111) Bragg peak intensity showed strong dependence on the excitation fluence. After exposure to a sufficiently intense x-ray pulse, the peak intensity dropped to zero within 300 fs, i.e. faster than one oscillation period of the A_1g mode at room temperature. Our analysis indicates a nonthermal origin of a lattice disordering process, and excludes interpretations based on electron-ion equilibration process, or on thermodynamic heating process leading to plasma formation.

Zeolite-loaded alginate-chitosan hydrogel beads as a topical hemostat

Hemorrhage is the leading cause of preventable death after a traumatic injury, and the largest contributor to loss of productive years of life. Hemostatic agents accelerate hemostasis and help control hemorrhage by concentrating coagulation factors, acting as procoagulants and/or interacting with erythrocytes and platelets. Hydrogel composites offer a platform for targeting both mechanical and biological hemostatic mechanisms. The goal of this work was to develop hydrogel particles composed of chitosan, alginate, and zeolite, and to assess their potential to promote blood coagulation via multiple mechanisms: erythrocyte adhesion, factor concentration, and the ability to serve as a mechanical barrier to blood loss. Several particle compositions were synthesized and characterized. Hydrogel bead composition was optimized to achieve the highest swelling capacity, greatest erythrocyte adhesion, and minimal in vitro cytotoxicity. These results suggest a polymer hydrogel-aluminosilicate composite material may serve as a platform for an effective hemostatic agent that incorporates multiple mechanisms of action. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1662-1671, 2018.

Diffraction based Hanbury Brown and Twiss interferometry at a hard x-ray free-electron laser

X-ray free-electron lasers (XFELs) provide extremely bright and highly spatially coherent x-ray radiation with femtosecond pulse duration. Currently, they are widely used in biology and material science. Knowledge of the XFEL statistical properties during an experiment may be vitally important for the accurate interpretation of the results. Here, for the first time, we demonstrate Hanbury Brown and Twiss (HBT) interferometry performed in diffraction mode at an XFEL source. It allowed us to determine the XFEL statistical properties directly from the Bragg peaks originating from colloidal crystals. This approach is different from the traditional one when HBT interferometry is performed in the direct beam without a sample. Our analysis has demonstrated nearly full (80%) global spatial coherence of the XFEL pulses and an average pulse duration on the order of ten femtoseconds for the monochromatized beam, which is significantly shorter than expected from the electron bunch measurements.

Nanosecond X-Ray Photon Correlation Spectroscopy on Magnetic Skyrmions

We report an x-ray photon correlation spectroscopy method that exploits the recent development of the two-pulse mode at the Linac Coherent Light Source. By using coherent resonant x-ray magnetic scattering, we studied spontaneous fluctuations on nanosecond time scales in thin films of multilayered Fe/Gd that exhibit ordered stripe and Skyrmion lattice phases. The correlation time of the fluctuations was found to differ between the Skyrmion phase and near the stripe-Skyrmion boundary. This technique will enable a significant new area of research on the study of equilibrium fluctuations in condensed matter.

Itinerant and Localized Magnetization Dynamics in Antiferromagnetic Ho

Using femtosecond time-resolved resonant magnetic x-ray diffraction at the Ho L_{3} absorption edge, we investigate the demagnetization dynamics in antiferromagnetically ordered metallic Ho after femtosecond optical excitation. Tuning the x-ray energy to the electric dipole (E1, 2p→5d) or quadrupole (E2, 2p→4f) transition allows us to selectively and independently study the spin dynamics of the itinerant 5d and localized 4f electronic subsystems via the suppression of the magnetic (2 1 3-τ) satellite peak. We find demagnetization time scales very similar to ferromagnetic 4f systems, suggesting that the loss of magnetic order occurs via a similar spin-flip process in both cases. The simultaneous demagnetization of both subsystems demonstrates strong intra-atomic 4f-5d exchange coupling. In addition, an ultrafast lattice contraction due to the release of magneto-striction leads to a transient shift of the magnetic satellite peak.

A liquid jet setup for x-ray scattering experiments on complex liquids at free-electron laser sources

In this paper we describe a setup for x-ray scattering experiments on complex fluids using a liquid jet. The setup supports Small and Wide Angle X-ray Scattering (SAXS/WAXS) geometries. The jet is formed by a gas-dynamic virtual nozzle (GDVN) allowing for diameters ranging between 1 μm and 20 μm at a jet length of several hundred μm. To control jet properties such as jet length, diameter, or flow rate, the instrument is equipped with several diagnostic tools. Three microscopes are installed to quantify jet dimensions and stability in situ. The setup has been used at several beamlines performing both SAXS and WAXS experiments. As a typical example we show an experiment on a colloidal dispersion in a liquid jet at the X-ray Correlation Spectroscopy instrument at the Linac Coherent Light Source free-electron laser.

Ultrafast energy- and momentum-resolved dynamics of magnetic correlations in the photo-doped Mott insulator Sr2IrO4

Measuring how the magnetic correlations evolve in doped Mott insulators has greatly improved our understanding of the pseudogap, non-Fermi liquids and high-temperature superconductivity. Recently, photo-excitation has been used to induce similarly exotic states transiently. However, the lack of available probes of magnetic correlations in the time domain hinders our understanding of these photo-induced states and how they could be controlled. Here, we implement magnetic resonant inelastic X-ray scattering at a free-electron laser to directly determine the magnetic dynamics after photo-doping the Mott insulator Sr2IrO4. We find that the non-equilibrium state, 2 ps after the excitation, exhibits strongly suppressed long-range magnetic order, but hosts photo-carriers that induce strong, non-thermal magnetic correlations. These two-dimensional (2D) in-plane Néel correlations recover within a few picoseconds, whereas the three-dimensional (3D) long-range magnetic order restores on a fluence-dependent timescale of a few hundred picoseconds. The marked difference in these two timescales implies that the dimensionality of magnetic correlations is vital for our understanding of ultrafast magnetic dynamics.

Three-dimensional charge density wave order in YBa2Cu3O6.67 at high magnetic fields

Charge density wave (CDW) correlations have been shown to universally exist in cuprate superconductors. However, their nature at high fields inferred from nuclear magnetic resonance is distinct from that measured with x-ray scattering at zero and low fields. We combined a pulsed magnet with an x-ray free-electron laser to characterize the CDW in YBa2Cu3O6.67 via x-ray scattering in fields of up to 28 tesla. While the zero-field CDW order, which develops at temperatures below ~150 kelvin, is essentially two dimensional, at lower temperature and beyond 15 tesla, another three-dimensionally ordered CDW emerges. The field-induced CDW appears around the zero-field superconducting transition temperature; in contrast, the incommensurate in-plane ordering vector is field-independent. This implies that the two forms of CDW and high-temperature superconductivity are intimately linked.

Imaging Molecular Motion: Femtosecond X-Ray Scattering of an Electrocyclic Chemical Reaction

Structural rearrangements within single molecules occur on ultrafast time scales. Many aspects of molecular dynamics, such as the energy flow through excited states, have been studied using spectroscopic techniques, yet the goal to watch molecules evolve their geometrical structure in real time remains challenging. By mapping nuclear motions using femtosecond x-ray pulses, we have created real-space representations of the evolving dynamics during a well-known chemical reaction and show a series of time-sorted structural snapshots produced by ultrafast time-resolved hard x-ray scattering. A computational analysis optimally matches the series of scattering patterns produced by the x rays to a multitude of potential reaction paths. In so doing, we have made a critical step toward the goal of viewing chemical reactions on femtosecond time scales, opening a new direction in studies of ultrafast chemical reactions in the gas phase.

Demonstration of simultaneous experiments using thin crystal multiplexing at the Linac Coherent Light Source

Multiplexing of the Linac Coherent Light Source beam was demonstrated for hard X-rays by spectral division using a near-perfect diamond thin-crystal monochromator operating in the Bragg geometry. The wavefront and coherence properties of both the reflected and transmitted beams were well preserved, thus allowing simultaneous measurements at two separate instruments. In this report, the structure determination of a prototypical protein was performed using serial femtosecond crystallography simultaneously with a femtosecond time-resolved XANES studies of photoexcited spin transition dynamics in an iron spin-crossover system. The results of both experiments using the multiplexed beams are similar to those obtained separately, using a dedicated beam, with no significant differences in quality.

A time-dependent order parameter for ultrafast photoinduced phase transitions

Strongly correlated electron systems often exhibit very strong interactions between structural and electronic degrees of freedom that lead to complex and interesting phase diagrams. For technological applications of these materials it is important to learn how to drive transitions from one phase to another. A key question here is the ultimate speed of such phase transitions, and to understand how a phase transition evolves in the time domain. Here we apply time-resolved X-ray diffraction to directly measure the changes in long-range order during ultrafast melting of the charge and orbitally ordered phase in a perovskite manganite. We find that although the actual change in crystal symmetry associated with this transition occurs over different timescales characteristic of the many electronic and vibrational coordinates of the system, the dynamics of the phase transformation can be well described using a single time-dependent 'order parameter' that depends exclusively on the electronic excitation.

All-diamond optical assemblies for a beam-multiplexing X-ray monochromator at the Linac Coherent Light Source

All-diamond optical assemblies holding state-of-the-art type IIa diamond crystals enable the construction of a beam-multiplexing X-ray double-crystal monochromator for hard X-ray free-electron lasers. Details on the design, fabrication and X-ray diffraction characterization of the assemblies are reported.

A double-crystal diamond (111) monochromator recently implemented at the Linac Coherent Light Source (LCLS) enables splitting of the primary X-ray beam into a pink (transmitted) and a monochromatic (reflected) branch. The first monochromator crystal, with a thickness of ∼100 µm, provides sufficient X-ray transmittance to enable simultaneous operation of two beamlines. This article reports the design, fabrication and X-ray characterization of the first and second (300 µm-thick) crystals utilized in the monochromator and the optical assemblies holding these crystals. Each crystal plate has a region of about 5 × 2 mm with low defect concentration, sufficient for use in X-ray optics at the LCLS. The optical assemblies holding the crystals were designed to provide mounting on a rigid substrate and to minimize mounting-induced crystal strain. The induced strain was evaluated using double-crystal X-ray topography and was found to be small over the 5 × 2 mm working regions of the crystals.

The landscape of cytokinin binding by a plant nodulin

Nodulation is an extraordinary symbiotic interaction between leguminous plants and nitrogen-fixing bacteria (rhizobia) that assimilate atmospheric nitrogen (in root nodules) and convert it into compounds suitable for the plant host. A class of plant hormones called cytokinins are involved in the nodulation process. In the model legume Medicago truncatula, nodulin 13 (MtN13), which belongs to the pathogenesis-related proteins of class 10 (PR-10), is expressed in the outer cortex of the nodules. In general, PR-10 proteins are small and monomeric and have a characteristic fold with an internal hydrophobic cavity formed between a seven-stranded antiparallel β-sheet and a C-terminal α-helix. Previously, some PR-10 proteins not related to nodulation were found to bind cytokinins such as trans-zeatin. Here, four crystal structures of the MtN13 protein are reported in complexes with several cytokinins, namely trans-zeatin, N6-isopentenyladenine, kinetin and N6-benzyladenine. All four phytohormones are bound in the hydrophobic cavity in the same manner and have excellent definition in the electron-density maps. The binding of the cytokinins appears to be strong and specific and is reinforced by several hydrogen bonds. Although the binding stoichiometry is 1:1, the complex is actually dimeric, with a cytokinin molecule bound in each subunit. The ligand-binding site in each cavity is formed with the participation of a loop element from the other subunit, which plugs the only entrance to the cavity. Interestingly, a homodimer of MtN13 is also formed in solution, as confirmed by small-angle X-ray scattering (SAXS).

Firmware lower-level discrimination and compression applied to streaming x-ray photon correlation spectroscopy area-detector data

We present a data acquisition system to perform on-the-fly background subtraction and lower-level discrimination compression of streaming x-ray photon correlation spectroscopy data from a fast charge-coupled device (CCD) area detector. The system is built using a commercial frame grabber with an on-board field-programmable gate array. The system is capable of continuously processing at least 60 CCD frames per second each consisting of 1024 × 1024 16-bit pixels with ≲ 15,000 photon hits per frame at a maximum compression factor of ≈95%.

Depletion-induced structure and dynamics in bimodal colloidal suspensions

Combined small angle x-ray scattering and x-ray photon correlation spectroscopy studies of moderately concentrated bimodal hard-sphere colloidal suspensions in the fluid phase show that depletion-induced demixing introduces spatially heterogeneous dynamics with two distinct time scales. The adhesive nature, as well as the mobility, of the large particles is determined by the level of interaction within the monomodal domains. This interaction is driven by osmotic forces, which are governed by the relative concentration of the constituents.

Dynamics at the liquid-vapor interface of a supercooled organic glass former

We investigated the dynamics near the liquid-vapor interface of the supercooled model organic glass former dibutyl phthalate by using surface-sensitive x-ray scattering techniques. Our results reveal significant enhancement of the relaxation rate over a wide length-scales range. The analysis of the dispersion relation of long-wavelength surface fluctuations yields a nonzero value of the share modulus near the free surface. At the molecular level, the dynamics in the near surface region (10-15 nm) is inhomogeneous. The mobility is decreasing with increasing distance from the free surface. Below the bulk glass transition, two distinct relaxation times were observed differing by 1 order of magnitude. The observed fast relaxation proves the existence of a high mobility liquidlike surface layer of 10 nm thickness on top of a frozen in bulk system.

Characterization of edible oils using total luminescence spectroscopy

Total luminescence spectroscopy was used to characterise and differentiate edible oils and additionally, to control one of the major problems in the oil quality--the effect of thermal and photo-oxidation. We studied several vegetable oils available on the Polish market, including soybean, rapeseed, corn, sunflower, linseed and olive oils. Total luminescence spectroscopy measurements were performed using two different sample geometries: front-face for pure oil samples and right-angle for transparent samples, diluted in n-hexane. All the samples studied as n-hexane solutions exhibit an intense peak, which appears at 320 nm in emission and 290 nm in excitation, attributed to tocopherols. Some of the oils exhibit a second long-wavelength peak, appearing at 670 nm in emission and 405 nm in excitation, belonging to pigments of the chlorophyll group. Additional bands were present in the intermediate range of excitation and emission wavelengths; however, the compounds responsible for this emission were not identified. The front-face spectra for pure oils included chlorophyll peaks for most samples, and some additional peaks in the intermediate range, while the tocopherol peaks were comparatively less intense. The results presented demonstrate the capability of the total luminescence techniques to characterise and differentiate vegetable oil products, and additionally, to characterize the effect of thermal and photo-oxidation on such products. In the photo-oxidation experiments, special attention was paid to possible involvement of singlet oxygen. Experiments were done to monitor the highly specific O2(1delta(g)) --> O2(3sigma(g)-) singlet oxygen emission at 1270 nm. Thus, total luminescence spectroscopy presents an interesting alternative to time-consuming and expensive techniques such as gas or liquid chromatography, mass spectrometry and other methods requiring wet chemistry steps.

Dynamics of cervical langerhans cell counts in the course of HPV-positive CIN treatment with the use of human recombinant interferon gamma

OBJECTIVES

Langerhans cells play a pivotal role as professional antigens presenting cells in cervical epithelium, thus changes in their density or/and function may profoundly influence the proper activation of the afferent arm of immune response in cases of HPV-related intraepithelial lesions.

AIM OF THE STUDY

Assessment of intraepithelial Langerhans cell count changes in CIN I/CIN II after human recombinant interferon gamma (IFNgamma) application and correlation with clinical outcome.

MATERIAL & METHODS

The present study is a part of prospective trial on IFNgamma application in the treatment of CIN I/CINII associated with high-risk HPV infection. Seventeen subjects underwent uniform IFNgamma treatment (four intracervical injections in a two-day interval for a total dose of 6,000,000 IU). Langerhans cells were stained within cervical punch biopsy specimens with the use of polyclonal anti-S-100 antibody according to the three-step indirect peroxidase protocol, and their mean count calculated for the following groups: before IFNgamma treatment launching, immediately after completion of the treatment, and after two months of follow-up.

RESULTS

The analysis revealed a rapid and significant increase in Lagerhans' cell count immediately after treatment completion (21.17/mm2 and 25.94/mm2, respectively, at p = 0.019) which further increased in the group of complete response (in 9 subjects; 32.22/mm2). After transient elevation of the Langerhans' cell count it returned to a level even lower than initially in the non-responder group (4 subjects; 20.25/mm2).

CONCLUSION

Our data strongly support the observation from static studies suggesting that regression of HPV-related cervical lesions is associated with increased density of epithelial Langerhans cells.

Recombinant human interferon gamma in the treatment of cervical intraepithelial neoplasia (CIN) associated with human papillomavirus (HPV) infection

Human papillomavirus (HPV) proteins E6 & E7 are considered to be the constitutively expressed neoantigens in a vast majority of cervical squamous intraepithelial lesions and cancers. Data available from in-vitro, animal, and small clinical trials suggest that the immunological properties of interferon gamma might enhance early viral protein presentation, thus stimulating a cytotoxic response. In order to study this effect in vivo we undertook a trial in which 20 women with a definite diagnosis of cervical intraepithelial neoplasia (CIN) grade I or II with coexistent high-risk HPV infection (detected by the Hybrid Capture System) underwent four months observation followed by intracervical administration of INFgamma in cases without spontaneous regression (17 cases). Human recombinant interferon gamma 1-b (Imukin) was administered intracervically four times in equal doses in two-day intervals to a total dose of 6,000,000 IU. The results of therapy were verified by punch biopsy evaluation and HPV-DNA testing two months after completion, and revealed a complete response in nine women (complete regression of CIN and remission of HPV infection in 53% of treated cases) and partial response in four cases (lower grade of CIN or/and remission of HPV infection--23.5%). The differences between spontaneous (before treatment) and treatment-related regressions were significant at p < 0.05. We conclude that in selected cases (mainly young women who have not completed their procreation and are compliant with the therapy) a conservative approach to CIN management with intracervical IFNgamma injections seems to be a valuable method.

Photophysical properties of lumichromes in water

The photophysics of lumichrome, 1-methyllumichrome, and lumiflavin in water solutions have been investigated. Fluorescence lifetimes of 2.7 and 2.2 ns were observed for lumichrome and 1-methyllumichrome, respectively, the corresponding triplet state lifetimes of 17 and 18 micros have been obtained from the transient absorption spectra. Evidence for long lived species with absorption maxima near 450 nm and lifetimes of ca. 400 micros has been found in the transient absorption spectra of both lumichromes. Quantum yields for the sensitised production of singlet oxygen, phi(Delta), are 0.36 and 0.41 for lumichrome and 1-methyllumichrome, respectively, in D(2)O.

A school-based strategy to assess children's environmental exposures and related health effects in economically disadvantaged urban neighborhoods

The School Health Initiative: Environment, Learning, Disease (SHIELD) study is a novel school-based investigation of children's environmental health in economically disadvantaged urban neighborhoods of Minneapolis. This article describes the study design and summarizes lessons learned about recruiting and monitoring this historically understudied population. The SHIELD study focused on measuring children's exposures to multiple environmental stressors [volatile organic chemicals (VOCs), environmental tobacco smoke, allergens, bioaerosols, metals, pesticides, polychlorinated biphenyls (PCB), phthalates] and exploring related effects on respiratory health (e.g., lung function) and learning outcomes (e.g., standardized test scores, academic achievement). It involved intensive exposure monitoring, including environmental measurements inside and outside the children's schools and inside their homes, personal measurements with passive dosimeters worn by the children, and biological marker measurements in blood and urine. The SHIELD participants comprised a stratified random sample of 153 "index" children and 51 of their siblings enrolled in grades 2-5 at two adjacent elementary schools. The Minneapolis Public Schools (MPS) assisted with identifying, contacting, recruiting, and monitoring this population, which traditionally is difficult to study because families/children are highly mobile, speak a diversity of languages, frequently do not have a telephone, endure economic hardships, often do not trust researchers, and have a spectrum of unconventional lifestyles and living arrangements. Using a school-based approach, the overall SHIELD enrollment (response) rate was 56.7%, with a wide disparity between English-speaking (41.7%) and non-English-speaking (71.0%) families/children. Most children remained involved in the study through both monitoring sessions and exhibited an acceptable degree of compliance with study protocols, including providing blood and urine samples. Results indicate that it is both practical and affordable to conduct probability-based exposure studies in this population, but that it is also important to improve our understanding of factors (e.g., cultural, economic, psychological, social) affecting the willingness of families/children to participate in such studies, with special emphasis on developing cost-effective recruitment methods.

Synthesis and photophysical properties of fluorophore-labeled abscisic acid

The 8'-benzophenone, 8'-dansylhydrazone, 3'-S-(2-ethyldansylamide), and 3'-S-acetamidofluorescein derivatives of the plant hormone abscisic acid (ABA) have been synthesized for use in photoaffinity labeling (the benzophenone derivative) or fluorescence probe experiments and have been spectroscopically characterized. One of the three fluorescent compounds, the 3'-tethered fluorescein derivative, exhibits spectroscopic and photophysical properties which indicate that it could be an excellent fluorescent probe of ABA interactions in vivo. The 3'-tethered fluorescein and ABA moieties do not interact strongly, so that the fluorescence properties of the fluorescein-labelled hormone are very similar to those of fluorescein itself. Measurements of the absorption, emission, and fluorescence excitation spectra, fluorescence quantum yields, and fluorescence decay parameters of this derivative as a function of pH indicate that the photophysics is dominated by ground and excited state prototropic equilibria involving only the fluorescein moiety. The fluorescein dianion is the only significant absorber and emitter at pH > 6.7, whereas only the cation absorbs and emits at pH < 0. In the intervening pH range, strong emission from the monoanion and weak emission from two neutral species, tentatively assigned to the zwitterion and the lactone of the fluorescein moiety, is observed.Key words: abscisic acid, fluorescein, synthesis, photophysics.

[Surgical approach in cases of adnexal pathology in adolescents and young women]

Retrospective analysis comprised 108 cases of adnexal pathology found at laparotomy in the group of adolescents and young women up to the age of 25. The most common condition necessitating the laparotomy was hemorrhagic corpus luteum (24% of cases). Adnexal cysts of different but benign histological structure had been found in 30.5% of cases. Malignant germ cell tumors (6 cases--dysgerminoma and teratoma immaturum) all of which at Ia stage at the time of laparotomy, had been treated conservatively with unilateral salpingo-oophorectomy. Authors suggest that the conservative approach should be applied in most cases of adolescents' adnexal pathology.

[Endometriosis in adolescents and young women. Can we afford to delay the diagnosis?]

Retrospective analysis performed on medical records of 129 adolescents and young women treated surgically at I Dept. of Surgical Gynaecology during the nine years period (1989-1998) revealed 22 cases (17%) of endometriosis. Main indication for surgical intervention, apart from dysmenorrhoea and cyclic abdominal pain, had been the presence of endometriod cyst, as disclosed by ultrasound investigation (66%). Despite of negative result of imaging or clinical examination subjective complaints necessitated laparotomy in 27% of cases. According to American Fertility Society endometriosis classification, 17% subjects presented endometriosis in I stage, 17%--in stage II and remaining 66%--endometrioid cysts with stage III. Authors conclude, that in cases with persistent abdominal pain, not responding to conventional therapy, diagnostic laparoscopy/laparotomy in young women should not be delayed, unless endometriosis is suspected.

Studies of the photophysics and spectroscopy of alloxazine and related compounds in solution and in the solid state

The absorption and emission spectra and the fluorescence lifetimes and quantum yields of alloxazine and several of its N- and C- methyl-substituted derivatives, including two isoalloxazines, have been measured in a nonpolar solvent (1,2-dichloroethane), a polar aprotic solvent (acetonitrile), and a polar protic solvent (ethanol). The excited state decays are all single exponential, suggesting that only one emitting species is present in all cases. The spectroscopic data show that the emitting species is the π,π* electronic excited state corresponding to the ground state of the absorbing molecule; there is no evidence of excited state proton transfer for any of these solutes in any of the three solvents. The longer lifetimes and larger fluorescence quantum yields of the isoalloxazines compared with the alloxazines can be attributed exclusively to significantly slower rates of radiationless relaxation in the excited isoalloxazines. The remission and emission spectra of these same compounds adsorbed on cellulose are similar to the corresponding absorption and emission spectra in homogeneous solution, suggesting that the emitting species are the same in the adsorbed state as they are in homogeneous solution. However, the adsorbed excited species exhibit non-exponential temporal decay, attributed to inhomogeneities in the binding of the chromophore to cellulose. The emission spectra of polycrystalline samples of alloxazine and lumichrome suggest the possible occurrence of double intermolecular excited state proton transfer, but this interpretation is not supported by the further photophysical data obtained here.Key words: photophysics, spectroscopy, alloxazine, lumiflavin, cellulose.

[Use of the Digene Hybrid Capture System for identification of the human papillomavirus (HPV-Human Papillomavirus) in women with cervical dysplasia]

The study was performed to assess prevalence of HPV-DNA infections using the Hybrid Capture System (Vira Papl Vira Typ ). In a group of 228 female patients with Papanicolaou smear grade I and II, high oncogenic risk HPV infections were found in the 15.78% and low oncogenic risk--in 7.01% of the investigated patients. In a group of 324 women with diagnosed CIN, the high oncogenic HPV infection were found in 70.4% of them (CIN I/II-60%, CIN III-87.11%), and the low oncogenic risk HPV infections in 11.1%.

["Cold turkey" detoxification of drug, narcotic and chemical addicts conducted at the Occupational Diseases and Toxicology Ward of the Polish Center of Occupational Medicine in Poznan in 1986-1996]

In this paper we have discussed the method of the "pure" detoxification (without the use of any psychotropics) of patients addicted to drugs, narcotics and chemicals treated at the Occupational Diseases & Toxicology Ward of the WCMP in Poznań. The material includes 152 cases of addicted patients who were treated in the Ward in the period from 1986 till 1996. Our research proved that the applied method is safe for the patients. We also found that addicts sharing hospital room with general medicine, not addicted patients, experience a positive effects in the process of treatment and resocialization.

[Usefulness of clinical evaluation for the level of CA-125 antigen and ultrasonographic color Doppler examination in diagnosis of ovarian tumor]

The objective of our study was to evaluate the predictive value of serum CA-125 levels and transvaginal ultrasound with color Doppler flow mapping (RI) in patients with benign and malignant ovarian tumors. The retrospective analysis included 78 women in whom 92 tumors were detected. Eleven patients had ovarian carcinoma (a total of 16 tumors). Predictive values were compared for tumor morphology, lowest resistive index (RI) < 0.40 and CA-125 > 35 IU/ml. Sensitivity, specificity, positive and negative predictive values in differentiating malignancy were highest for RI (94%, 87% 87% and 94%, respectively). Morphological criteria or CA-125 levels alone had lower predictive accuracy. Combining of the correctly identified all of the malignancies. It is concluded that preoperative transvaginal ultrasound with color Doppler flow mapping is valuable tool in the assessment of adnexal tumors and can be of assistance in prediction of ovarian cancer.

[Beeswax pessary in conservative treatment of uterine prolapse]

The own method of uterine prolapse treatment with the use of beeswax pessary is presented. The described method is applied in cases where general health conditions do not allow to perform the surgery. The study revealed that the beeswax is a good material to make a vaginal pessary. It's great plasticity allows individual modelling in compliance with anatomical conditions of treated patient. That provides the proper stability of uterine position. The risk of possible urinary stress incontinence due to uterine reposition is also diminished.

[Endometriosis in clinical materials from the years 1981-1990]

In the group of 213 women with diagnosed endometriosis, after the histological analysis of the samples obtained during surgical procedure the following factors have been determined: the character and frequency of complaints, prevalence of the disease depending on the age of patients, it's localisation, coexistence with the neoplasms of the genital tract, indications for the surgical treatment and it's type. Taking into account the difficulties in diagnosing endometriosis, it's occurrence in young women and the possibility of malignant transformation along with the coexistence with malignant neoplasms of genital tract, we are convinced that the surgical intervention should be undertaken in order to achieve the better cure rate as well as to improve the accuracy of diagnosis.

[Local coagulation confined to the uterus and adnexa--case description]

The seldom occurring local intravascular coagulation confined to the uterus and adnexa is described. The authors give attention on diagnostic difficulties in described case.

[Personal observations concerning surgical treatment of urinary stress incontinence in women]

Own observations concerning surgical treatment of urinary stress incontinence based upon the clinical follow-up of 82 treated women are presented. Depending on the method of surgical treatment, patients with urinary stress incontinence have been divided into 3 groups: I group-(42 women), where retropubic colpo-uretero-pexy has been performed following the rules previously suggested by Tanagho, Sprogis et al., with 92.8% of positive result, II group-(34 women), where Mieszczerski or Fothergill type of surgery has been performed, with 88.2% of positive results, and III group-(6 women), where vaginal vault has been suspended to the musculo-fascial flap, with positive results in all treated patients. The obtained results suggest that in every case of urinary stress incontinence the conservative approach should be the primary strategy of treatment. Analysis of the results revealed that retropubic colpo-uretero-pexy was an effective surgical method of urinary stress incontinence treatment in women with no cystocele and with proper uterine statics. In patients with correct uterine statics but with coexisting cystocoele, even of a minor grade, retropubical kolpouretropexy should be joined with the surgery from a vaginal access.