An inversion method for calculating formation and borehole parameters in X-ray lithology density logging.

The use of X-ray sources in place of the 137Cs sources used in traditional lithology density logging methods has become a new trend in the development of nuclear logging techniques. How to eliminate the effects of drilling fluids or mudcake in the measurement process is a key question that determines the accuracy of measurement. In order to reduce the effects of mudcake and improve the accuracy of measurement of formation parameters, this paper presents an inversion method that can accurately calculate formation and borehole parameters and is suitable for X-ray lithology density logging. The general process of this inversion method is described below. First, a response model for broad-beam attenuation during X-ray lithology density logging is derived. Subsequently, the responses of four detectors under various formation and borehole conditions are studied by means of Monte Carlo simulation, and the energy spectra measured by each detector are divided into four energy windows (ranges) depending on the correlation with formation parameters. Finally, accurate values of formation and borehole parameters are obtained through iterative inversion using the Levenberg-Marquardt (LM) algorithm. The results of this study show that compared with previously established analysis methods, the inversion method based on forward modeling can effectively improve the accuracy of measurement of formation density and lithology index during X-ray lithology density logging, reduce the influence of the borehole environment, and overcome the deficiencies of data processing techniques based on the spine and ribs plot.

Corrections of fast neutron inelastic scattering effects on D-T neutron porosity logging.

With the continuous development of logging tools with controllable neutron sources, improving the processing method to make their measurements more consistent with those obtained by chemical sources has become a development trend in well logging based on controllable sources. To study the correction method that is not constrained by other parameters and does not require chemical sources, the reasons for the differences in the neutron porosity responses of D-T and chemical sources are theoretically analyzed. Then the fast neutron slowing-down process is divided into two stages depending on neutron energy. A method to correct the effects of inelastic scattering in D-T neutron porosity is established through the derivation of the theoretical relationship. Finally, the effectiveness of the correction method is verified using the simulation and measured data. The results show that after inelastic scattering correction, the measurement results of neutron porosity logging with controllable and chemical sources are highly consistent, and there is a close correspondence between the two types of sources in terms of measured data. Therefore, the proposed inelastic scattering correction method can effectively replace density correction to make the measurement results of the D-T neutron source more consistent with those of chemical sources. This study is of great significance for the wide application of neutron porosity measurement with controllable neutron sources and the replacement of radioactive sources in logging tools in the future.

Hypoglycemic activity of Origanum vulgare L. and its main chemical constituents identified with HPLC-ESI-QTOF-MS.

Origanum vulgare L. (O. vulgare) is an important medicine food homology in diabetes. The present study aimed to assess the hypoglycemic effect of the leaf extract of O. vulgare in HepG2 and HepG2-GFP-CYP2E1 (E47) cells, and disclose its potential active components by the HPLC-ESI-QTOF-MS method. Firstly, we evaluated the anti-diabetic capacity of the leaf extract of O. vulgare through inhibition of α-glucosidase activity, promotion of glucose uptake, inhibition of glycosylation and relieving of oxidative stress. Secondly, the promoter activity, the mRNA and protein expression of PEPCK and SREBP-1c, and the expression of CPY2E1 and GLUT2 in the O. vulgare mediated anti-diabetic capacity were analyzed in HepG2 and E47 cells. Finally, HPLC-ESI-QTOF-MS analysis was performed to identify the herb's main components under 280 nm irradiation. In vitro assays demonstrated that the extract inhibited α-glucosidase activity, promoted glucose uptake, inhibited glycosylation and relieved oxidative stress, which suggested that O. vulgare leaf extract has a strong hypoglycemic capacity. Moreover, mechanistic analysis also showed that the extract decreased the promoter activity and the mRNA and protein expression of PEPCK and SREBP-1c. In addition, the extract inhibited the expression of CPY2E1 and enhanced the expression of GLUT2. Moreover, the UV chromatogram at 280 nm showed six main peaks, identified as amburoside A (or 4-(3',4'-dihydroxybenzoyloxymethyl) phenyl O-ß-d-glucopyranoside), luteolin 7-O-glucuronide, apigenin 7-O-glucuronide, rosmarinic acid, lithospermic acid and a novel compound, demethylbenzolignanoid, based on accurate MS data. This work supported the ethnopharmacological usage of O. vulgare as an antidiabetic herbal medicine or dietary supplement and identified its main phenolic compounds.

Impact of photoelectric effect on X-ray density logging and its correction.

This paper studied the impact of the photoelectric effect of X-ray density logging in order to improve the accuracy of X-ray measurement density. Firstly, the laws governing the changes of the Compton scattering and photoelectric effect of X-rays in the formation were analyzed based on the principle of X-ray attenuation in the formation and using the XCOM program. Secondly, the impact of photoelectric effect on X-ray density logging was studied on the basis thereof. Thirdly, a method for correcting photoelectric effect by calculating the formation bulk density using the counts in both lithology window and density window was proposed. Finally, the proposed method was verified through MCNP simulation. The results indicate that photoelectric effect was an important factor affecting the accuracy of X-ray density measurement, and the lower the X-ray energy was, the greater the impact of photoelectric effect on X-ray density measurement would be and the lower the accuracy of density measurement would be. As the γ-rays released from a Cs-137 source were at a high energy level, the impact of photoelectric effect was basically negligible when the formation bulk density was calculated using the counts in density window; on the contrary, the X-rays released from the X-ray source was at a low energy level, the impact of photoelectric effect could not be neglected when the formation bulk density was measured using X-ray. The method for calculating the formation bulk density proposed in this paper can effectively eliminate the impact of photoelectric effect and reach up to a measurement accuracy level of about 0.01g/cm3, providing a theoretical foundation for accurate density measurement during X-ray density logging.

A research on the effects of formation elements on the spatial distribution of D-D induced γ-ray source.

The position and intensity of induced γ-rays are highly affected by formation factors during D-D controllable source density logging, resulting in a relatively low-level accuracy of density measurement. To improve the accuracy of density measurement, the laws governing the changes in the spatial distribution of induced γ-ray source from the viewpoint of the effects of formation elements are studied in this paper. On the basis of the fundamental theory of D-D controllable source density measurement, this paper first analyzed the generation process of D-D induced capture γ-ray source, then analyzed the effects of main formation elements involved in capture reaction on the spatial distribution of induced capture γ-rays, and, finally, analyzed and discussed the effects of various formation elements from the perspective of macroscopic formation factors. The results indicate that the spatial distribution of capture γ-rays is mainly affected by fast neutron deceleration, thermal neutron diffusion, and absorption, while the occurrence of these three processes is mainly related to the formation elements undergoing capture reaction. Among such formation elements, hydrogen has the greatest effect on the spatial distribution of capture γ-rays. Particularly, when hydrogen content increases from 0 to 5%, the induced γ-ray source changes from 100 cm to 25 cm in terms of its spatial position. The main reason is that when hydrogen content in the formation increases, the action of fast neutron deceleration becomes stronger, more γ-rays approach toward the neutron source, and the intensity of γ-rays also increases gradually at the same time; comparatively, other elements (especially chlorine) in the formation have smaller effects on the spatial positions of induced γ-rays and greater effects on the intensity of induced γ-rays. The main reason is that for different types and contents of formation elements, their thermal neutron capture cross-sections vary. For elements with large capture cross-sections, as their contents increase, more thermal neutrons will be captured and the intensity of γ-rays will also increase. As the sensitivity of induced γ-ray source to different formation elements varies, the spatial distributions of induced γ-ray source in formations with varying porosity, lithology, and salinity are also different. This research provides the theoretical basis for identifying the laws governing the spatial distribution of D-D induced γ-ray source and correcting the effects of formation elements on density measurement.

Study on the impact of pair production interaction on D-T controllable neutron density logging.

This paper considers the effect of pair production on the precision of D-T controllable neutron source density logging. Firstly, the principle of the traditional density logging and pulsed neutron density logging are analyzed and then gamma ray cross sections as a function of energy for various minerals are compared. In addition, the advantageous areas of Compton scattering and pair production interactions on high-energy gamma ray pulse height spectrum and the errors of a controllable source density measurement are studied using a Monte Carlo simulation method. The results indicate that density logging mainly utilizes the Compton scattering of gamma rays, while the attenuation of neutron induced gamma rays and the precision of neutron gamma density measurements are affected by pair production interactions, particularly in the gamma rays with energy higher than 2MeV. By selecting 0.2-2MeV energy range and performing proper lithology correction, the effect of pair production can be eliminated effectively and the density measurement error can be rendered close to the precision of chemical source density logging.

Microgranular variant of acute promyelocytic leukemia with der(17) ins(17;15): A case report and review of the literature.

Acute promyelocytic leukemia (APL) with variant translocations is rare. The patient of the present case report, a 2-year-old male with a microgranular variant of APL carrying der(17) ins(17;15) translocation, exhibited fever and epistaxis. The complete blood count showed marked leukocytosis with 72% atypical promyelocytes, anemia and thrombocytopenia. Conventional cytogenetic analysis of the bone marrow cells revealed a karyotype of 47, XY, add(3)(q29), -7, ins(17;15)(q12;q14q22),+21,+mar. The promyelocytic leukemia/retinoic acid receptor α (PML/RARα) rearrangement and insertion were confirmed by fluorescence in situ hybridization. The PML/RARα transcripts were not detected by the reverse transcription polymerase chain reaction, and the patient was diagnosed with microgranular variant M3 APL. The patient achieved remission after a 30-day treatment and was still in remission during a recent follow-up. The present findings suggest that the ins(17;15) variant in APL may not be associated with an unfavorable prognosis. In summary, we reported an extremely rare case of APL with der(17) ins(17;15) abnormality in a pediatric patient and reviewed the literature.

Nonsurgical factors of digital replantation and survival rate: A metaanalysis.

The aim of this metaanalysis was to evaluate the association between nonsurgical factors and survival rate of digital replantation. A computer search of MEDLINE, OVID, EMBASE and CNKI databases was conducted to identify literatures for digital replantation, with the keywords of "digit," "finger" and "replantation" from their inception to June 10, 2014. Based on the inclusion and exclusion criteria, data were extracted independently by two authors using piloted forms. Review Manager 5.2 software was used for data analysis. The effect of some nonsurgical factors (gender, age, amputated finger, injury mechanisms, ischemia time and the way of preservation) on the survival rate of digital replantation was assessed. The metaanalysis result suggested that gender and ischemia time had no significant influence on the survival rate of amputation replantation. However, the survival rate of digital replantation of adults was significantly higher than that of children. The guillotine injury of a finger was easier to replant successfully than the crush and avulsion. The little finger was more difficult for replantation than thumb. Survival rate of fingers stored in low temperature was higher than that in common temperature. The present metaanalysis suggested that age, injury mechanism, amputated finger and the way of preservation were significantly associated with the survival rate of digital replantation.

Development of a simple detector response function generation program: the CEARDRFs code.

A simple Monte Carlo program named CEARDRFs has been developed to generate very accurate detector response functions (DRFs) for scintillation detectors. It utilizes relatively rigorous gamma-ray transport with simple electron transport, and accounts for two phenomena that have rarely been treated: scintillator non-linearity and the variable flat continuum part of the DRF. It has been proven that these physics and treatments work well for 3×3″ and 6×6″ cylindrical NaI detector in CEAR's previous work. Now this approach has been expanded to cover more scintillation detectors with various common shapes and sizes. Benchmark experiments of 2×2″ cylindrical BGO detector and 2×4×16″ rectangular NaI detector have been carried out at CEAR with various radiactive sources. The simulation results of CEARDRFs have also been compared with MCNP5 calculations. The benchmark and comparison show that CEARDRFs can generate very accurate DRFs (more accurate than MCNP5) at a very fast speed (hundred times faster than MCNP5). The use of this program can significantly increase the accuracy of applications relying on detector spectroscopy like prompt gamma-ray neutron activation analysis, X-ray fluorescence analysis, oil well logging and homeland security.

Accuracy and borehole influences in pulsed neutron gamma density logging while drilling.

A new pulsed neutron gamma density (NGD) logging has been developed to replace radioactive chemical sources in oil logging tools. The present paper describes studies of near and far density measurement accuracy of NGD logging at two spacings and the borehole influences using Monte-Carlo simulation. The results show that the accuracy of near density is not as good as far density. It is difficult to correct this for borehole effects by using conventional methods because both near and far density measurement is significantly sensitive to standoffs and mud properties.

[Study on morphology of surface atoms conformation of nanogold-based genechip].

Conformations of surface atoms in various stages of nanogold-based genechip testing were scanned by the atomic force microscope based on the scanning tunneling microscope. The findings were: First, the surface atoms of genechip slide (formylphenyl glass) were in a regular porous-arrangement; Second, after combination with probe, the regular porous arrangement changed to be irregular; Third, after hybridization with the target nucleic acid, the surface atoms were once again in a cable-like arrangement which was relatively structured and intensively cross-parallel. However, after the silver staining, the surface atoms showed a larger block structure with serious unevenness. From these results we can intuitively know the process and differences in probe combination, nucleic acid hybridization, and silver staining. Moreover, the relevant experiment was verified at the micro-level.

Development of a biochip using antibody-coated gold nanoparticles to detect specific bioparticles.

This study developed a method of detecting bioparticles such as Salmonella that exist in the biological samples. The method employed a substrate with interlaced comb-like electrodes into which the mixtures of biological samples and antibody-coated gold nanoparticles were added. The alternative signals with appropriate frequency bands were then conducted into the comb-like electrodes to change the dielectrophoresis force. The gold-modified Salmonella can be adsorbed on the edges of the electrodes and isolated from various biological samples. The impedance of the adsorbed Salmonella on the edges of the electrodes was measured and comparison of the impedance between the electrodes with and without Salmonella can quantify the amount of the adsorbed Salmonella.

[A study on surface plasmon resonance-based gene chip].

The surface plasmon resonance (SPR)-based gene chip was prepared according to the following processes: First, a film of nanogold, which was synthesized by using Frens' method, was plated on chip by Chlorauric acid/hydroxylamine method. Then probes were fixed on nanogold film by Self-assembled monolayer (SAM) technology. Subsequently, the fixing time and concentration of probes, the sensitivity and the specificity of the chip were optimized. Our results suggested that the chip plated with 2.5 nm nanogold film has a better SPR reflection, and when fixed by probes for 4.5 h at the concentration of 1 500 nmol/L, the gene chip also shows a fine performance of detection and can identify accurately the mismatch between bases in SPR detection system. The gene chip constructed in the research can be used for SPR sensor detection.

Detection of specific bioparticles using antibodies-coated gold nanoparticles and dielectrophoretic impedance measurement.

In this study, we developed an easy and quick test capable of identifying specific bacteria in one hour. The protocol was established based on the measurement of bacteria quantity on a biochip with comb-like electrodes. Gold nanoparticles coated with anti-Salmonella antibody were used to enhance the dielectrophretic property of Salmonella spp. on the biochip to facilitate the sensitivity.