Partical Size Research Articles

Диэлектрическая модель влажных почв для территории юга Западной Сибири в диапазоне частот 3 МГц – 1 ГГц

The wet soil's dielectric model whose input parameters are frequency, volumetric moisture content, and physical clay content are presented. This model was developed based on statistical analysis of dielectric permettivity data for five soil samples with differ partical size distribution from steppe and forest-steppe climate zones within the territory of southern Western Siberia. A comparison of dielectric data obtained empirically and calculated using the model for one type of soil is carried out. The obtained results will find application in assessing the radiophysical characteristics of the underlying surface in the frequency range from 3 MHz to 1 GHz.

Exploring the effectiveness of polyhydroxy complexing agents in sapphire chemical mechanical polishing: Combining experiments and theoretical calculation

High efficiency and environmentally friendly is the core development in sapphire chemical mechanical polishing (CMP) slurry. Therefore, complexing agents xylitol (XL) and mannitol (MA) were used to enhance the CMP performance of sapphire. The results showed that the addition of 0.2 wt% MA resulted in the optimal MRRs of C-, A- and R-plane sapphire, which are 4.878 µm/h, 2.242 µm/h and 2.731 µm/h, and the surface roughness is 0.274 nm, 0.262 nm and 0.260 nm, respectively. Partical size detection, XPS, FTIR and density functional theory (DFT) calculations results showed that the addition of MA did not alter the mechanical action, but can react with Al(OH)4− to form softer complexes, which improves MRRs and surface quality.

MINERALOGICAL AND PHYSICO-CHEMICAL CHARACTERISATION OF CLAY MATERIALS FROM KWILU-NGONGO (Kongo-Central, DR Congo)

Clay materials collected from two sites (Camp-Beton and Kwilu-Bricks) in the Kwilu-Ngongo region located between 5°30’0’’S and 14°40’60’’E, in the Kongo Central province (DRC), Ten samples selected and subjected to mineralogical, physico-chemical and geotechnical studies with a view to their characterization. Mineralogical analysis by X-ray diffraction made it possible to identify the following minerals: quartz, feldpasth, iron oxide and simple clay minerals including kaolinite. In addition to this kaolinite we also find illite, chlorite and vermiculite. The partical size analysis led to the differentiation of three fractions including: the fine clay fraction, the silty fraction and the sandy fraction. As for the Atterberg Limits, the plasticity Limit ranges from 17 to 30% while the average plasticity index is 13 %. Chemical analyzes made it possible to identify the major oxides elements below: SiO2, Al2O3, TiO2, Fe2O3, K2O, Na2O and MgO.

Adsorptive Removal of Methylene Blue Dye by Annealed Waste Foundry Sand

Under optimized experimental conditions, the efficient removal of methylene blue dye from annealed waste foundry sand as adsorbent was carried out. The X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Field emission scanning electron microscopy (FE-SEM) and partical size analysis were used to confirm the crystalline structure, composition and morphology of the prepared sorbent. The sorbent achieved its highest adsorption capacity by interacting with an aqueous solution contaminated with methylene blue dye. A comparison was made between the sorbent and three annealed sands based on their dye removal efficiency adsorption data over time. By using Langmuir and pseudo second-order kinetic models to the sorption data, it is observed that both physical and chemical processes can influence the removal process. According to experimental data, annealed waste foundry sand (WFS-300) has a high adsorption efficiency and methylene blue adsorption follows.

Immunoevaluation of hydrophobic modified polyethyleneimine as cationic polymer adjuvant

Polyethyleneimine (PEI) is a cationic polymer that has excellent gene transfection effects as a gene transfection reagent. Its excellent proton sponge effect has attracted much attention in the field of vaccine adjuvants. However, its high positive charge density leads to high toxicity, which limits its application. In this paper, polyethyleneimine modified by stearyl chloride was used to reduce toxicity to obtain SA-PEI. The partical size of composite particles formed by SA-PEI adjuvant and ovalbumin (OVA) were smaller than 200 nm. In vivo experiments of Balb/c mice experiments showed that, compared with unmodified PEI, SA-PEI could significantly enhance the specific immune response to OVA and may promote the endocytosis of macrophages. This study clearly provides a promising cationic polymer adjuvant for the vaccine field.

Effect Dynamic Stability of Atmospheric Boundary Layer on Plume Downward Flux Emitted from Daura Refinery Stacks

The vertical motion of air that enhances or restricts the atmospheric turbulence through atmospheric boundary layer is known as "atmospheric stability", in which any movement of atmospheric components such as water vapor, aerosols, etc. are affected by the atmospheric stability. The aim of this research is to test the effect of atmospheric boundary layer stability on the amount of downward aersols flux at 10um (PM10) emission from stacks of Daura refinery, and estimated of deposition dust aerosols PM10 amount in area around the Daura refinery. In this study, hourly atmospheric stability based on similar theory of Monin-Obukhov length is calculated from archived data of the European Center for Medium Range Weather Forecast, and deposition velocity (Vd) for PM10 that is emitted from stacks Daura Refinery is calculated using the stability parameter (L). PM10 concentration is estimated according to the Gaussian model, which is used along with deposition velocity at this partical size in order to produce downward sedimentation flux (Fp) at distances 1000, 5000 and 10000 m from stack point sources emission. Results show that areas located to the south and southeast of the refinery receive large amounts of deposited flux values through stable weather conditions, where the accumulated PM10 amounts during one month have recorded 1.5 million μg /m2.s in January at a distance of 1000 m from refinery center stacks, while this amount reaches 532 million μg/m2.s during July due to the high emission rates resulting from burning fuel oil during July. The percentages of PM10 sedimentation decreased with the distance from the refinery to 1712 and 322839 μg /m2.s at a distance 10 km from the refinery in January and July, respectively. According to this method, the accumulated amount of PM10 in square meters can be estimated at any time, if atmospheric stability conditions and the domain of wind direction are known.

Adsorption study of some inorganic elements on the surface of activated charcoal prepared from ceratonia siliqua

This study included the process of adsorption of some inorganicelements known as environmental risk (Cd, Cr, Cb, Pb) of its watersolutions on the surface of activated charcool to ceratonia siliqua . Thepercentage of adsorption and isothermal adsorption curves werecalculated according to equation, as well as the effect of temperature , pHand particle size of adsorbent on the adsorption of these elements. Thestudy included the comparative study of the adsorption with naturalceratonia siliqua powder. The results showed an optimum conditions atPH=5 and the partical size of adsorbent was 500 μm, while thepercentage of adsorption ranged from 81% to 93%

Preparation of Active Iron powder by Electrochemical method

In this work, active iron powder was prepared at high purity 99.9% and partical size less than 53 micron by using electrolytic cell contained an electrolyte of ferrous sulphate (70 gm /L) ,Sodium chloride (100 gm /L),at temperature of 80C and pH 2.0. Seven Steel electrodes were used as anodes and cathodes.The product is suitable for use in metalloceramic applications and manufacture of parts for machinery ,various alloys ,in chemical industry ,re-chargeable batteries The procedure ,the equipments and results were described .

Characterization of a novel polysaccharide from red ginseng and its ameliorative effect on oxidative stress injury in myocardial ischemia

BackgroundRed ginseng (RG) was widely used as traditional Chinese medicine (TCM) or dietary supplement. However, few researches had been reported on the red ginseng polysaccharide (RGP).MethodsIn this study, a novel heteropolysaccharide named RGP1-1 was fractionated sequentially by DEAE-52 column and Sephadex G-100 gel column. The primary structure of RGP1-1, including glycosyl linkages, molecular weight, monosaccharide composition, morphology and physicochemical property were conducted by nuclear magnetic resonance (NMR), gas chromatography-mass spectrometer (GC–MS), atomic force microscope (AFM), scanning electron microscope (SEM), differential scanning calorimetry-thermogravimetric analysis (DSC-TG) and so on. The effect of RGP1-1 in preventing and treating myocardial ischemia was evaluated by an animal model isoprenaline (ISO) induced mice.ResultsRGP1-1, with a homogeneous molecular weight of 5655 Da, was composed of Glc and Gal in the ratio of 94.26:4.92. The methylation and NMR analysis indicated the backbone was composed of → 1)-Glcp-(4 → and → 1)-Galp-(4 →, branched partially at O-4 with α-D-Glcp-(1 → residue. Morphology and physicochemical property analysis revealed a triple-helical conformation, flaky and irregular spherical structure with molecule aggregations and stable thermal properties of RGP1-1. And it contained 6.82 mV zeta potential, 117.4 nm partical size and polymerization phenomenon. Furthermore, RGP1-1 possessed strong antioxidant activity in vitro and in vivo, RGP1-1 could decrease cardiomyocyte apoptosis and myocardium fibrosis of mice in histopathology and it could decrease significantly the serum levels of cardiac troponin (cTnI), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), malondialdehyde (MDA). Western blot analysis showed that RGP1-1 can increase the expression of main protein Nuclear factor E2-related factor 2(Nrf2), NAD(P)H:quinone oxidoreductase 1 (NQO1), heme oxygenase-1(HO-1) and kelch-like ECH-associated protein1(keap1) in oxidative stress injure progress, and therefore regulate the pathway of Nrf2/HO-1.ConclusionThe above findings indicated that RGP1-1 had an improving effect on ISO-induced myocardial ischemia injury in mice, as novel natural antioxidant and heart-protecting drugs.

Evaluation of the toxicity effects of microplastics and cadmium on earthworms.

Microplastics (MPs) and heavy metal pollution have become research hotspots in recent years. This study focused on the comprehensive evaluation of the toxicity effect on Eisenia fetida under combined exposure to MPs and the heavy metal cadmium (Cd). With Cd concentration, MPs concentration and MPs partical size as stress factors, the TOPSIS model was constructed to explore the toxicity levels of the stress factors. A short-term co-exposure test and a long-term co-exposure test were designed by orthogonal combination tests with equivalent toxicity levels. The activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), glutathione peroxidase (GPX), glutathione S transferase (GST), and acetylcholinesterase (AChE) and the contents of protein (TP), glutathione (GSH), and malondialdehyde (MDA) in earthworms were determined. Integrated biological responses version 2 (IBRv2) was used to evaluate the toxicity of MPs and Cd combined exposure on earthworms. The results showed that the toxicity ratio of Cd concentration, MPs concentration and MPs partical size was 46 to 29 to 25. Combined exposure to MPs and Cd enhanced the activities of SOD, POD, CAT, GPX and GST, MDA and GSH contents also increased, while the AChE activities were inhibited. SOD, GPX and GST play important roles in the resistance of earthworms to pollutant stress. During short-term co-exposure, Cd concentration had antagonistic effects with on MPs concentration and MPs partical size, while they showed synergistic effects during long-term co-exposure.

Mns@N/S-C Anode Electrode with High Lithium Storage Property By Simple Polyol Refluxing Method

Transition-metal sulfides are of significant interest as rechargeable battery anodes owing to their low cost, wide availability, eco-friendliness, and high theoretical capacities. However, the structural change due to the volume change during the electrochemical reaction and the capacity decrease due to the dissolution of polysulfide remain as problems. Herein, a simple one-pot polyol refluxing method is used for fabricating a manganese sulfide (MnS) electrode composited with nitrogen and sulfur co-doped carbon (MnS@NS-C) for high-power lithium-ion batteries. This composite electrode is a carbon-coated nanostructure, exhibits unique spherical particle morphology with optimized average partical size (300 < x < 500nm) and porous features. Owing to its nanostructure, porous nature, and an electrically conducting carbon coating network co-doped with heteroatoms, the composite electrode overcomes the strong structural variations and polysulfide dissolution to afford high practical storage capacities, long-term cycle stability, and outstanding rate capability. The MnS@NS-C electrode demonstrated high reversible lithium storage capacities of 999 mAh g-1 at 0.1 A g-1, the highest reversible capacity of 761 mAh g-1 at 2 A g-1 for over 300 cycles, and average rate capacities of 453 mAh g-1 at 10 A g-1. In-situ X-ray diffraction investigations indicated a uniquely combined intercalation-cum-conversion reaction mechanism leading to β-Li2(1-x)MnS, Li2S, and Mn discharge products. The results of this study can provide deep insights into understanding reaction mechanism and motivate further study of transition-metal sulfides for prospective high-energy battery applications. References N. Nitta, F. Wu, J. T. Lee and G. Yushin, Mater. Today, 2015, 18, 252–264. V. Etacheri, R. Marom, R. Elazari, G. Salitra and D. Aurbach, Energy Environ. Sci., 2011, 4, 3243–3262. Y. Hao, C. Chen, X. Yang, G. Xiao, B. Zou, J. Yang and C. Wang, J. Power Sources, 2017, 338, 9–16. Y. Ye, C. Jo, I. Jeong and J. Lee, Nanoscale, 2013, 5, 4584–4605. L. Zhang, L. Zhou, H. Bin Wu, R. Xu and X. W. Lou, Angew. Chemie - Int. Ed., 2012, 51, 7267–7270.

Direct current (dc) bias effect on the dielectric constant of Dy and Ho-doped BaTiO3-based ceramic and MLCCs

With the increasing demand for the miniaturization, high capacitance and high reliability of the Multilayer Ceramic Capacitor (MLCC), the thickness of single dielectric layer is less than 1 μm and the original partical size of the powder has reached the scale less than 300 nm. In this paper, BaTiO3 powder of various partical sizes (150–500 nm) was modified with Dy and Ho through a chemical coating method. The dense and uniform ceramics in accordance with EIA X7R-type temperature stability were sintered under low oxygen partial pressure and good dielectric properties of dielectric constant >2000 and dielectric loss <1% were obtained. The grain size effect on the dielectric properties under various dc-bias field were systematically investigated. It is found that the fine-grain ceramic exhibits a lower absolute change of the dielectric constant and a higher dc-bias stability. Furthermore, the modified 150 nm BaTiO3 powders was made into 1210-type MLCCs, and the dielectric behavior of the MLCCs with different dc-fields and ac-fields were study over −55 °C–125 °C. It is found that the ac electric field had a greater influence on the dielectric properties at room temperature and below, and the dielectric constant variation under a dc-bias field was also greatly advanced for the modified fine-grain MLCCs. The results provide a reference for the design of the next generation of BME-MLCCs.

Experimental study on the combustion characteristics of aluminized nitrate ester plasticized polyether solid propellant under high pressure

Aluminized Nitrate Ester Plasticized Polyether high-energy solid propellant demonstrates bright application prospects due to its high-density specific impulse and satisfactory mechanical properties. The high-pressure experiment study were conducted on aluminized Nitrate Ester Plasticized Polyether to quantitatively investigate the burning rate characteristics at 1–7 MPa, and qualitatively analyse the agglomeration characteristics at 7 MPa. The burning rate experiment results indicate that the relationship between burning rate and pressure basically conforms to Vielle's burning rate law. When the ammonium perchlorate partice size decreases from 298 to 142 μm, the burning rate coefficient increases by 9.1% and the pressure index decreases by 7.6%. With the octogen particle size increasing from 15 to 150 μm, the burning rate coefficient and pressure index increases by 15.0% and 9.8%, respectively. When the aluminum particle size decreases from 30 to 16 μm, the burning rate parameters remain unchanged. While the aluminum particle size decreases from 16 to 2 μm, the burning rate coefficient increases by 20.5% and the pressure index decreases by 18.6%. The burning rate is significantly affected by octogen particle size and aluminum particle size has the vital influence on burning rate coefficient and pressure index. The agglomeration process and second mergence phenomenon at 7 MPa were observed for the first time and the agglomeration process mainly happens on the burning surface and above the burning surface under high pressure. Qualitative analysis shows that high pressure reduces the retention time of agglomerates on the burning surface and intensifies the combustion process of agglomerates, and coarse octogen can effectively reduce the agglomeration particle size at 7 MPa. The conclusions can provide insights into the influence of Nitrate Ester Plasticized Polyether composition on burning rate and the effect of high pressure on the agglomeration process in the motor.

Experimental Study of Compressed Soil Bricks with Partial Replacement of Soil by Bagasse Ash, Marble Powder and Rice Straw

The problem of pollution is increasing daily due to excessive production and improper disposal of the waste. some waste like ashes and stone powder can be easily utilize in the concrete or with any other construction material like paver block or bricks. To utilize material like marble powder bagasse ash and rice straw effectively the experimental study of Earth compressed bricks is conducted. This paper deals about the mechanical properties of earth compressed bricks which are made up of soil and the add-ons are marble powder, bagasse ash and rice straw fiber with different ratios of combination. This ratios are for marble powder 20%, 30% and 40%. for bagasse ash it is 7% 10% and 13% and for rice straw it is .5%, .75% and 1%. The compression property of bricks is increased when the marble powder is increased with less water absorption in soil because waste marble powder does not absorbs water and due to its fine partical size it fills the voids in the bricks and creates good packing of the bricks. Water is absorbed by Rice Straw and bagasse ash which results in increase of the water absorption capacity of earth compressed bricks.

Carbon-Based Composites as Anodes for Microbial Fuel Cells: Recent Advances and Challenges.

Owing to the low price, chemical stability and good conductivity, carbon-based materials have been extensively applied as the anode in microbial fuel cells (MFCs). In this review, apart from the charge storage mechanism and anode requirements, the major work focuses on five categories of carbon-based anode materials (traditional carbon, porous carbon, nano-carbon, metal/carbon composite and polymer/carbon composite). The relationship is demonstrated in depth between the physicochemical properties of the anode surface/interface/bulk (porosity, surface area, hydrophilicity, partical size, charge, roughness, etc.) and the bioelectrochemical performances (electron transfer, electrolyte diffusion, capacitance, toxicity, start-up time, current, power density, voltage, etc.). An outlook for future work is also proposed.

Validated Stability Indicating Method for Determination of Indapamide in Pharmaceutical Formulation

A stability indicating method for Indapamide in an oral antihypertensive tablet and bulk dosage forms was developed and validated by reverse phase HPLC (RP-HPLC). The proposed RP-HPLC Shisheido Capcell Pak C18 column was used and column dimension was 250mm × 4.6mm i.d., 5μm partical size at ambient temperature. The mobile phase Methanol and Phosphate Buffer pH 5.8 (60:40) was run in isocratic mode at a flow rate of 1.0ml/minute. The wavelength of Indapamide was selected at 241nm. Indapamide was found as single peak in the chromatogram at 6.58 min. The different chromatographic conditions were applied to determine the drug in pharmaceutical dosage form. The linearity of the proposed method was found in a range of 0.2-1.2μg/ml with coefficient of correlation (r2) value 0.999, slope 8360 and intercept -77.78. The percent RSD of intraday precision and interday precision were found in range of 0.498 - 1.661 and 0.882 - 1.623 respectively. The average accuracy of the method at three different levels of 50, 100 and 150 % were found to be 100.67, 99.50 and 100.65, respectively. The LOQ and LOD expressed as signal to noise ratio (S/N) were found to be 0.03 and 0.08μg/mL with good accuracy and precision. Indapamide was exposed to different stress conditions like alkaline, acidic, thermal, oxidative and photolytic. The stressed samples were analyzed by the proposed method. The proposed methods can be used for routine analysis stability testing and assay of Indapamide in quality control laboratories.

Purifying Crude Petroleum by Using Porous Ceramic Balls

Background: Background: In this study ceramic crude petroleum filter was prepared from Iraqi White Kaolin with ratio (70%) and Alumina (Al2O3) with ratio (30%), with natural additives Palm Frond with ratios (5,10,15,25,35 and 45)% in different partical size to produce pores, formed by dry pressing then fairing at 1100(˚C). The filters are harmless and environmentally friendly materials. Some assessments were carried out, such as (apparent porosity ratio, water absorption ratio, and apparent density). From the test results obtained the apparent porosity was 60.7% , water absorption was 89.3% and an apparent density of 0.68% with a 45% ratio of fine (P.F). Methods: Size and distribution of pores were characterized by using Scanning Electron Microscope (SEM). The crude petroleum treated with filters evaluated by tests such as (API Gravity, Sulfur Content, Asphaltenes Content, and Metallic Content). Results: The result of API Gravity before immersion crude petroleum filter balls was 24.70 and after immersion crude petroleum filter balls for 7 days for 30 % (P.F) increase to 31.0 and reach to 32.5 after immersion for 14 days. Sulfur Content before immersion crude petroleum filter balls was 3.76 and after immersion crude petroleum filter balls for 7 days for 30 % (P.F) decrease down to 3.1 and reach to 2.6 after immersion for 14 days. Conclusion: So Asphaltenes content before immersion crude petroleum filter balls was 6.68 and after immersion crude petroleum filter balls for 7 days 30 % (P.F) decreased down to 2 and reach to 1.6 after immersion for 14 days, metallic contact such as Vanadium and Nickel before immersion crude petroleum filter balls respectively was 86 ppm, 32 ppm while after immersion crude petroleum filter balls for 7 days they become 53.26 ppm and 15.35 ppm and for 14 days they reached to 47.52 ppm and 11.43 ppm respectively.

Combining patterned membrane filtration and flocculation for economical microalgae harvesting

Membranes have a lot of potential for harvesting microalgae, but mainly membrane fouling and high harvesting costs linked to low fluxes are hampering their breakthrough. Patterned membranes can reduce fouling by enchancing local turbulences close to the membrane surface on one hand, and by increasing the active area per m2 of installed membrane on the other. Flocculation can further increase membrane permeance by increasing microalgal partical size and reducing the fraction of free organic matter in the feed. In current study, the effect of polyethylene glycol (PEG) in the casting solution of patterned polysulfone membranes was investigated to better tune the performance of the patterned membranes, together with the effects of cross-flow velocity and chitosan dosage on membrane fouling. The energy consumption and total harvesting cost, extrapolated to a full-scale microalgal harvesting, were then estimated. The patterned membrane prepared with a 28w% PEG concentration showed the highest clean water permeance (900±22 L/m2 h bar) and membrane permeance in a microalgal suspension (590±17 L/m2 h bar). Patterned membranes showed a lower filtration resistance (15% permeance decline at the end of filtration) than flat membranes (72%) at a cross-flow velocity of 0.0025 m/s. Increasing cross-flow velocity could increase membrane permeance in most cases. The highest stable membrane permeance (110±17 L/m2 h bar) and the lowest filtration resistance were achieved when combining patterned membrane filtration with flocculation at optimized chitosan dosage. A very low energy consumption (0.28 kWh/kg) and harvesting cost (0.16 €/kg) were achieved under these conditions.

Mitochondrial Genome-Derived Mc-COX2 with Novel Characteristics Predicts Prognosis of Patients with Chronic Lymphocytic Leukemia

Background Circular RNAs (circRNAs), a novel family of non-coding RNAs, have crucial roles in cancer progression. Conventional research is mainly focus on nuclear genome derived circRNAs (nu-circRNAs). The biological and clinical characteristics of mitochondrial genome derived-circRNAs (mt-circRNA) remains largely unknown, especially in chronic lymphocytic leukemia (CLL), the most prevalent incurable B-cell neoplasm in western countries. Lack of convenient and reliable clinical biomarkers is a hindrance in monitoring the progression of CLL. It is in urgent need of screening effective new biomarkers and exploring potential therapeutic targets associated with CLL initiation and progression. Recent studies have shown that circRNAs are enriched and stable in serum exosomes. However, the biological mechanisms of exosomal circRNAs remain unclear. In this study, we attempted to identify the novel characteristics of a mt-circRNA mc-COX2, which was abundant in plasma exosomes and could be involved in the progression of CLL. Since CLL patients have specific expression features of exosomal circRNAs in plasma, the function of the circRNAs and their clinical significance is urged to be explored. Methods Firstly, to unveil circRNAs expression profiles in CLL, plasma samples from five treatment-naive CLL patients and five age-/sex-matched healthy donors (HDs) were collected for circRNA microarray analyses. Northern blot and RNA- FISH were conducted to verify the existence of circRNAs in mitochondria. qPCR and other functional analysis such as RNase R, actinomycin D and RIP experiments were carried out to demonstrated the clinical and biological characteristics of mc-COX2, one of the mt-circRNAs. Cell apoptosis ability was determined by FCM. Moreover, electron microscope, partical size analysis, FCM and Western blot were used to explore the existence of exosomes and q-PCR analysis was performed to detect the expression of mc-COX2. Results Mt-circRNAs were highly expressed in CLL patients plasma (Figure A, B). Herein, we reported a novel circRNA named as mc-COX2 which was generated from the COX2 gene on mitochondrial genome by back-splicing and closely related to prognosis of CLL patients (Figure C). The enrichment of mc-COX2 in the mitochondria was further confirmed by RNA-FISH (Figure D). Northern blot was performed using head-to-tail probe of mc-COX2 and the results showed that mc-COX2 was detectable within the splice sites (Figure E). Notably, obviously different from nu-circRNAs, mc-COX2 showed lower stability with lower tolerance to RNase R and actinomycin D, but it was much more stable compared with linear RNAs (Figure G, F). And mc-COX2 cannot bind to AGO2 protein, suggesting that it probably function via other mechanisms instead of acting as ceRNA (Figure H). Furthermore, the up-regulated expression of mc-COX2 was positively associated with leukemogenesis and worse survival of CLL patients (Figure I, J). CLL patients with TP53 deletion rather than mutation displayed higher expression of mc-COX2 (Figure K). The endogenous reduction of mc-COX2 could induce cell apoptosis (Figure L). In addition, we indicated that mc-COX2 was highly enriched in exosomes, by which circRNAs could enter the circulation and be readily measured in the serum (Figure M). Moreover, the existence of mc-COX2 in plasma suggests that mc-COX2 may serve as a potentially novel prognosis biomarker for CLL patients, guiding targeted therapy in clinic. Conclusions In summary, we demonstrated the existence and clinical significance of mc-COX2, a novel class of circRNA species abundant in CLL plasma exosomes for the first time, which was distinct from nu-circRNAs. Furthermore, the specific high expression of mc-COX2 in CLL plasma which was strongly correlated with P53 deletion, can indicate worse prognosis of CLL patients. Taken together, our study not only identifies a novel circRNA which may serve as a new "liquid biopsy" biomarker for CLL prognosis but also expands the current knowledge regarding molecular mechanisms of circRNAs, providing potential diagnostic and therapeutic implications for CLL. It would be of great interest to explore the biogenesis of mt-circRNAs and their impact on mitochondrial function in future studies. Figure Disclosures No relevant conflicts of interest to declare.

EFFECT OF PARTICAL SIZE OF THE RAW MATERIALS USED IN FLOOR TILES CERAMIC INDUSTRY ON SOME PROPERTIES WHICH EXTRACTED FROM WESTERN DESERT OF ANBAR.

The partical size play a big role in determination of floor tiles products characteristics, So the idea of this research came to study the effect of the partical size of the raw materials (caoline , glass sand , limestone, sodium silicate ) which extracted from the Anbar western desert in Iraq ,Including various types of stones and metals and it's consider as greater field for metals in Middle East, The effect of partical size on some physical properties such as water adsorption, resistance for thermal shock ,shrinkage after pride and the mechanical properties which represent by durability,We used raw materials with partical size 53 , 65 , 77 , 85 , 110 and 140 µm and used manufacturing methods similar to that used in General company of ceramic industry in Anbar province from where mixing ratio, incineration conditions. The study showed that the partical size play a big role in determination of products characteristics, So the best size of raw materials was 77 µm give the lowest ratio of adsorption of water which is 14.5% and the resistance of thermal shock 150 thermal period , the shrinkage ratio was the least possible 0.5%, also we noticed improvement in durability which was 137 kg .m-2.