Evolution of the Micropore Structure of Ammonium Perchlorate during Low-Temperature Decomposition and Its Combustion Characteristics

Ammonium perchlorate (AP) is a common oxidant in solid propellants, and its thermal decomposition characteristics at low temperatures (less than 240 °C) are key to the study of the thermal safety of propellants. Here, the low-temperature thermal decomposition characteristics of AP were investigated at 230 °C. The micromorphology of the low-temperature decomposition residues was characterized by scanning electron microscopy and 3D nano-computed tomography in order to analyse the evolution of microscopic pore structures, and the effect of the AP pore structure on combustion performance was then tested and analysed with a homemade closed bomb. The results demonstrate that the low-temperature decomposition of AP first occurs near the surface of the particles, simultaneously starting at multiple points and forming pores, and then gradually expands towards the interior until almost all of the pores connect with one other. Compared with ordinary AP, porous AP has a significantly improved combustion rate. When the ratio of porous AP to Al was 80:20, the peak pressure in the closed bomb was increased by 2.7 times; the rate of change in peak pressure increased 34 times, leading to a higher reaction speed and higher reaction intensity, and a typical explosion reaction occurred.

Passive autocatalitic recombiner characteritics calculation during severe accident on AES-2006 NPP

A modern NPP is equipped by containment to hold radioactive substances and ionizing radiation bounded as design margins prescribe. Hydrogen mitigation system is used to protect containment against hydrogen fire and detonation. The system includes a scope of passive autocatalitic recombiners. Hydrogen is transformed into water, passing through said recombiners. The reaction occurs on catalyst surface. The main catalyst material is a palladium doped platinum. Hydrogen mitigation system parameters during severe accident are of interest. Wise admitted for NPP full scale tests are impossible, so the main analysis are calculations. Recombiner consists of catalytic block and stuck. The stuck provides reagents feeding and products evacuation enhancing natural convection transport. A model for calculations is suggested for recombiner with a plate-type catalyst block. The two free parameters of the model are chemical reaction intensity on catalyst and unit drag. Said parameters are estimated experimental data based on. Passive autocatalitic recombiner characteritics during severe ac- cident on AES-2006 NPP are calculated. The unit capacity is found not less that specification points. Catalyst temperatures, even the mean one, are above 500 °С, exhaust jet temperature exceeds 150 °С. Hydrogen content is high in the jet. Capacity increases linearly with hydrogen concentration at the unit entrance. Atmospheric temperature influence is low. Hydrogen mitigation system overall capacity is constant for uniform or not uniform hydrogen distribution in the containment. The calculated data may be used for recombiner work estimation during accident on AES-2006 NPP.

Reproductive performance and luteal function of Santa Ines ewes inseminated by cervical retraction with fresh or frozen semen

SUMMARY The artificial insemination (AI) by cervical retraction using fresh or commercially available frozen semen was evaluated. Santa Inês ewes (n=151) were assigned in five groups. Natural mating (NM) composed the control group. Four groups were submitted to hormonal treatment and timed insemination by cervical retraction (CRI) or laparoscopy (LAI), using fresh or frozen semen. To perform CRI, the ewes were kept in standing position. The time required to penetrate the cervical canal and to perform CRI were recorded; local deposition of semen and the reaction intensity of the ewe (weak, moderate or strong) were measured. Blood samples were collected to perform the progesterone dosage at days 0, 3, 5, 12 and 17 (day 0 = AI/NM). Non-return to estrus rate (NRE), pregnancy (at D35) and fertility (birth / mated ewes) were evaluated. Mean time for cervical penetration and CRI were 52.8 ± 21.2s and 3:26min ± 47s, respectively. Reaction intensity to CRI was weak or moderate in 92.3% of the ewes. Serum levels of progesterone after CRI, LAI or NM were similar. NRE of the inseminated ewes were similar, except for CRI with frozen semen, which was lower (P<0.05). Fertility rates were similar between CRI and LAI (35.4% and 42.2%, respectively). Artificial insemination by cervical retraction with ewes in a standing position is practical, and does not change the progesterone profile, providing reproductive rates similar to laparoscopy. However, the use of this technique along with commercial frozen semen presents low fertility rate.

Analysing and optimizing the electrolysis efficiency of a lithium cell based on the electrochemical and multiphase model

Based on an electrochemical multiphysical simulation, a method for analysing electrolysis efficiency has been presented that considers the energy consumption required to produce a single kilogram of lithium and for the production of lithium, rather than the voltage in various parts. By adopting them as the criteria for analysing electrolysis efficiency in the lithium cell, several structural parameters have been optimized, such as the anode radius and anode–cathode distance. These parameters strongly affect the cell voltage and the velocity field distribution, which has a significant impact on the concentration distribution. By integrating the concentration distribution, the lithium production and energy consumption per kilogram, lithium is computed. By appointing the minimum of the chlorine and lithium concentration as the secondary reaction intensity, it is clear where the secondary reaction intensity is strong in the cell. The structure of a lithium electrolysis cell has been optimized by applying an orthogonal design approach, with the energy consumption notably decreasing from 35.0 to 28.3 kWh (kg Li) −1 and the lithium production successfully increasing by 0.17 mol.

Evaluation of estrogen receptor expression in low-grade and high-grade astrocytomas

SUMMARY OBJECTIVE: This study aims to compare estrogen receptor expression between low and high-grade astrocytomas. METHOD: A study using paraffin blocks of glial tumors from the Anatomy Pathology archives of São Marcos Hospital was carried out and began after approval by the Review Board of the Federal University of Piaui. Specimens were histochemically marked with an anti-ER alpha antibody. Brown-stained nuclei were considered positive, regardless of reaction intensity. Data were statistically analyzed using the Mann-Whitney test and Spearman's correlation. Statistical significance was established at p<0.05. RESULTS: The mean percentage of nuclei stained with anti-ER alpha in low-and high-grade astrocytomas was 0.04 and zero, respectively, while Spearman's correlation showed a strong negative association between low and high-grade tumors (p<0.001) and (r= −0.67), respectively. CONCLUSION: In the current study, estrogen receptor expression was positive only in low-grade astrocytomas and nil in high-grade astrocytomas, showing that ER expression declines with the grade of tumor malignancy.

Establishment of a procedure for producing the anti-b monoclonal antibody from B4C10D9 hybridoma cell line

There are two the most important blood group system in blood transfusion, that is the ABO system and the Rh system. The anti-A or anti-B antibodies in the blood of recipient cause strongly agglutination the red blood cells of donor bearing A or B antigens on their surface respectively. So, all donated blood and received blood must be typed group for the ABO system to be safe in blood transfusion. To blood grouping, used of know antisera reacts with the whole blood samples to determine antigen on the surface of red blood cell or use of know red blood cells reacts with the individual's serum to determine antibody. The serology method is widely used, antisera are usually monoclonal antibodies secreted by hybridoma cells. Our previous studies showed that the B4C10D9 hybridoma cell line generated anti-B monoclonal antibody was produced by hybridoma technology. This antibody causes specificity agglutination the red blood cells caring B antigen on their surface. It is classed as IgM antibody with it heavy chains are µ and κ light chains. The aim of the study was to produce the anti-B monoclonal antibody form B4C10D9 hybridoma cells line serve as a part of ABO blood grouping reagent. Based on results of experiments, procedure for producing the anti-B monoclonal antibody from B4C10D9 hybridoma cell line has also been established with following steps. At first, refresh the frozen B4C10D9 hybridoma cells and the density of B4C10D9 hybridoma cells is 4.0 x 104 cells/ml at 24 hours post-inoculation. Then the B4C10D9 hybridoma cells are splitted 1:5 every 48 hours for 2 times to obtain the cell biomass. In the next step, the hybridoma cells are splitted into 125 cm2 flasks with the initial cell density of 105 cells/ml. The B4C10D9 hybridoma cells density reach 9.9 x 106 cells/ml at 48 hours post-inoculation. After 144 hours of post-inoculation, collect culture medium and concentrate the anti-B monoclonal antibody by precipitation with saturated ammonium sulfate at a final concentration of 50%. If resuspending volume equals initial volume, then the anti-B monoclonal antibody titer reaches 1/256 and the antibody reaction intensity will be 3+. And if the obtained antibody solution volume equals one fifth of the original volume, then the anti-B monoclonal antibody titer reaches 1/1024, and the antibody reaction intensity will be 4+. Citation: Establishment of a procedure for producing the anti-b monoclonal antibody from B4C10D9 hybridoma cell line. Tap chi Sinh hoc, 39(3): 342-348. DOI: 10.15625/0866-7160/v39n3.10765. *Corresponding author: [email protected] Received 20 August 2017, accepted 20 September 2017

Sensitivity Study on Forest Fire Breakout and Propagation Conditions for Forest Fire Hazard Curve Evaluations

The authors have developed a probabilistic risk assessment method on a forest fire as one of external hazards. A hazard curve by heat effect of a forest fire had been obtained by using a logic tree in our previous study. The main application target of the forest fire probabilistic risk assessment is for sodium-cooled fast reactor systems. Databases for a hazard curve evaluation were based on forest fire records, meteorological and vegetation data of a studied area which is near a typical sodium-cooled fast reactor in Japan. There are two intensity parameters of heat effect of a forest fire, namely, reaction intensity and frontal fireline intensity. The hazard curves of these two intensities obtained in our previous study were referred to as “reference case” where constant breakout frequency throughout a day, equal probability distribution for potential breakout points, and firefighting effect on a forest fire were assumed as a priori. The reference reaction intensity and the fireline intensity became 935 kW/m2 and 107 kW/m for the annual exceedance frequency of 10−4/year, respectively. This paper describes a sensitivity study of the hazard curves on condition parameters where frequency/probability variables in the logic tree were varied within respective fluctuation ranges in order to evaluate quantitative effects on the frequency and/or intensity of the hazard curves. As for the forest fire breakout frequency and propagation probability, important variables are “fluctuation of breakout time”, “probability distribution fluctuation of breakout point”, and “firefighting effect on a probability of forest fire arrival at a nuclear power plant (NPP)”. The intensities increase in daytime due to sunshine, and the breakout probability in daytime is statistically 2.8 times higher than a daily average, and that in nighttime is 1/9 of the average. As a result, the hazard curves of the reaction intensity and the fireline intensity increased around 4% and 14% respectively in intensity direction in comparison with those of the reference case. The “fluctuation of breakout time” only affects the intensities of the hazard curves, but not the frequency. As for the “probability distribution fluctuation of breakout point”, one selected point is given higher probability than the other points. The hazard curves vary around +70% to −40% in frequency direction; each breakout point has different distance to the NPP and the forest fire arrival probability varies with a propagation duration. Namely, the longer duration, the higher probability of the extinguishment by firefighting, accordingly the lower probability of the arrival at the NPP. The “probability distribution fluctuation of breakout point” affects only the frequency of the hazard curves, but not the intensities. “Firefighting effect on a probability of forest fire arrival at an NPP” was conservatively assumed for the sensitivity study in which there is no firefighting action outside the NPP, hence all potential forest fires arrive at the NPP. The hazard curves remarkably increase around 40 to 80 times in frequency direction in comparison with those of the reference case. This is because most of forest fires in Japan are extinguished within one to two hours by fire departments, and the conditional probability of a forest fire arrival at an NPP from a potential breakout point with kilometer range distance was evaluated to be very low (i.e. less than a few percent). The “firefighting effect on a probability of forest fire arrival at an NPP” only affects the frequency of the hazard curves, but not the intensity. This study indicated that the most significant factor in the forest fire hazard curve is whether the firefighting action outside an NPP is expected before the arrival at an NPP.

ANALYSIS OF IMMUNOHISTOCHEMICAL EXPRESSION OF P16INK4a IN NEOPLASTIC SQUAMOUS CELL LESIONS OF CERVIX

Introduction: Cervical cancer is caused by persistent infection by high risk Human papilloma virus (HPV).Increasing expression of HPV viral oncogenes might be reflected by increased expression of p16. Hence immunohistochemical detection of p16INK4a is an easy and cost effective method than molecular detection of HPV. Aims: The purpose of this study were to evaluate the results of expression of p16INK4a in neoplastic squamous cell lesions of cervix in order to assess the association of HPV infection in those lesions and to study the pattern of expression of p16 and also to compare p16 expression in various histological types of cervical neoplastic squamous cell lesions by immunohistochemistry. Methods: Immunohistochemical analysis of p16 expression was performed on 26 paraffin embedded tissue samples, obtained from cervical biopsy including 2 early invasive squamous cell carcinoma (SCC), 6 large cell keratinizing SCC, 16 large cell non- keratinizing SCC and 2 cases small cell non-keratinizing SCC by using commercially available mouse monoclonal antibody to p16 (clone G175 – 405). Two parameters were evaluated in p16 expression: Percentage of p16 positive cells and reaction intensity of p16 immunostaining. The p16 expression was graded as negative; Grade 1, 2, 3 and its reaction intensity was graded as negative, weak, moderate and strong. Results: In the present study out of 26 cases, the incidence of large cell non- keratinizing SCC constituted majority of the neoplastic lesions of cervix (61.5%). Most of the SCC (96.15%) showed grade 3 scoring for p16 positivity except one case which showed grade 2 scoring. Majority of SCC cases (96%) showed strong reaction intensity for p16 immunostaining. Conclusion: In this study of 26 neoplastic sqaumous cell lesions, all patterns of cervical neoplasia showed p16 positivity. P16 may be useful as an adjunct in histological sections to detect HPV in those lesions.