Robust reservoir identification by multi-well cluster analysis of wireline logging data.

A novel clustering method is applied to well logs for improved rock type identification in hydrocarbon formations. For grouping the objects in the multi-dimensional data space, we propose a Most Frequent Value (MFV) based clustering technique applied to natural gamma ray, bulk density, sonic, photoelectric index, and resistivity logs. The MFV method is a robust estimator, which assists in finding the cluster centers more reliably than a more noise sensitive K-means clustering approach. The result of K-means cluster analysis highly depends on the choose of the initial centroids. To reduce the risk of inappropriately chosen starting values, we apply a histogram-based selection method to give the best position of the initial cluster centers. We assure the robustness of the solution by calculating the centroid as the MFV of the cluster elements and defining the overall deviation of cluster elements from the center by a weighted Euclidean (Steiner-) distance. The proposed workflow relies on a fully automated weighting of the cluster elements, which does not require a constraint on the statistical distribution of the observed variables. The processing of synthetic data shows high noise rejection capability and efficient cluster recognition even beside considerable amount of outlying and missing data; the accuracy is measured by the difference between the estimated and the exactly known distribution of cluster numbers. The clustering tool is first applied to single borehole data, then the procedure is extended to multi-well logging datasets to reconstruct the multi-dimensional spatial distributions of clusters revealing the lithological and petrophysical characteristics of the studied formations. A large in situ dataset acquired from several boreholes traversing Hungarian gas-bearing clastic reservoirs of Miocene age is analyzed. The accuracy of the field results is confirmed by core permeability measurements, independent well log analysis and a gradient metrics characterizing the noise rejection capability of the clustering method.

Proteomic analysis of plasma proteins after low-level laser therapy in rats.

The laser radiation absorbed by cells induces production of reactive oxygen species (ROS), followed by the development of oxidative stress. Proteins are major targets for ROS due to their abundance in biological systems. The aim of the present pilot study was to examine the effects of transcutaneous laser blood irradiation (TLBI), i.e., low-level laser therapy (LLLT) at 830 nm on plasma proteome in Wistar rats. Rats were irradiated in the heart area (i.e. coronary arteries) daily (i.e., for 9-day period), by commercially available GaAsAl diode laser (Maestro/CCM, Medicom Prague, Czech Republic, lambda=830 nm, power density 450mW/cm(2), daily dose 60,3 J/ cm(2), irradiation time 134 sec). The comparison of blood plasma proteome from irradiated and non-irradiated rats was performed utilizing 2D electrophoresis followed by MALDI TOF/TOF mass spectrometry. LLLT led to a quantitative change in the acute phase proteins with antioxidant protection i.e., haptoglobin (log(2) fold change (FC)=3.5), hemopexin (log(2) FC=0.5), fibrinogen gamma (log2 FC=1.4), alpha-1-antitrypsin (log(2) FC=-2.2), fetuin A (log2 FC=-0.6) and fetuin B (log2 FC=-2.3). In comparison to conventional biochemical methods, the changes in protein levels in blood plasma induced by LLLT offer a deeper insight into the oxidative stress response.

Differential Urinary Proteomic Analysis of Endometrial Cancer.

Endometrial cancer is one of the most frequent gynecological malignancies present in more than 95 % of all uterine cancers. In spite of that, screening of such disease is not commonly performed in clinical practice due to enormous costs and relatively low sensitivity. Therefore, developing an effective screening test to diagnose endometrial cancer at early stages is of great importance for the clinical area of investigation. In this work, we applied urinary proteomics (i.e., bottom-up proteomic approach followed by nano HPLC-ESI-MS/MS) in patients with endometrial cancer, with respect to find proteins aimed for the early diagnostics and screening. According to the results, the significant semi-quantitative changes were observed in urinary proteome of treated patients. The proteins that may be pivotal in pathogenesis of endometrial cancer, like cadherin-1 (CDH1), vitronectin (VTN) and basement membrane specific-heparan sulphate proteoglycan core protein (HSPG2) were down-regulated, when compared to the control group. Ultimately, it can be stated that urinary proteomics has a potential for the searching of cancer protein biomarkers based on their altered concentration.

[The influence of laser irradiation with different power densities on incisional wound healing in healthy and diabetic rats]. / Vplyv laserového ziarenia rôznych intenzít na hojenie incíznych rán u zdravých a diabetických potkanov.

INTRODUCTION: The optimal parameters of low level laser therapy (LLLT) are still under debate. It has been documented that a dose or 5 J/cm2 would be capable to accelerate the wound healing process in patients. However, the optimal delivering form, i.e. power intensity, is unknown. Therefore, the aim of our study was to compare different power densities of LLLT. MATERIALS AND METHODS: Sixteen male Sprague-Dawley rats were included in this experiment and randomized into two groups, normal healthy group and streptozotocine induced diabetic group. In general anesthesia four full thickness skin incisions were performed under standard aseptic conditions on the back of each rat and immediately closed using intradermal running suture. Three wounds were stimulated with diode laser (wavelength: 635 nm; daily dose 5 J/cm2; power densities: 1 mW/cm2, 5 mW/cm2 and 15 mW/cm2) each with different power density while the fourth wound served as control. Six days after surgery animals were sacrificed and samples removed for histological evaluation. RESULTS: Our study demonstrated that LLLT positively influences wound healing. The most significant changes were observed in wounds stimulated at the highest power density 15 mW/cm2. Since using the highest power density the shortest time is needed to achieve the optimal daily dose of 5 J/cm2, it can be suggested that 15 mW/cm2 might be optimal parameter for such a therapy in patients.

Early changes in the tensile strength and morphology of primary sutured skin wounds in rats.

The specific aim of this study was to measure the TS of rat skin wounds during the first week following surgical injury. Biomechanical and histological data were collected daily (days 1 to 7 following surgery) from separate groups of Sprague-Dawley rats (N = 12) each with two 3 cm long parallel skin incisions on the back. The wounds were immediately closed by four simple sutures. A control group (N = 15) was used to obtain TS measurements of unwounded skin. TS was measured by applying a ramp load until wound separation and estimated by dividing the yield strength by the wound area. The time course of biomechanical recovery followed a step-plateau pattern with the largest increase in TS observed one day after surgery (0 - 1.60 g/cm(2)). The plateau stage extended from day 1 to 5 (1.60 - 3.88 g/cm(2)). The final step (day 5-7) indicated a period of rapid rise in wound TS (3.88 - 11.57 g/cm(2)). Since even on day 7 the mean TS was only 4% of unwounded skin, the wound had to be protected from tensile loads. Histological analysis confirmed that the early changes in TS (day 1) correlated with the fibrin accumulation of the wound edges followed by a plateau stage caused by the tissue proliferation. The rapid increase in wound TS was characterized by cross-linking the incisions with collagen fibres with escalating organization. We conclude that from a biomechanical perspective, sutures can be removed during the "plateau phase", but the wound must be protected from tensile loads.

[Effect of laser irradiation of diode laser on healing of surgical wounds in rats]. / Vplyv laserového ziarenia diódového lasera na hojenie chirurgických rán u potkanov.

The aim of this work was to continue in previous study, which concerns biostimulation of skin wound healing evaluated after 24, 48, 120, 168 hours and so complete the chronological continuance of the process during the first seven days. Male, Sprague-Dawley rats (n=21) were used for the experiment. The rats were divided into 3 groups of 7 animals. In general anaesthesia (combination of xylazine, ketamine and tramadol) under aseptic condition two 3,5 cm long parallel skin incisions were performed on the left and right side of the rats spine and immediately sutured. The left wounds were daily stimulated with the diode laser (670 nm). The right wounds were not stimulated and served as control. The specimens of skin wounds were removed for histological evaluation 72, 96 and 144 hours after surgery. The biological specimens were stained with hematoxylin and eosin and histopathologically evaluated. In summary, in our histomorphological study of the influence of laser irradiation on primary wound healing evaluated after 72, 96 and 144 hours was concluded, that the healing of stimulated wounds was accelerated in comparison with controls. The histological evaluation showed earlier regress of inflammatory phase, faster finishing of reepithelization and acceleration in maturation phase. Presented experimental study completes the previous study and achieves the positive effect of biostimulation on all phases of skin wound healing in vivo.