Influencing factors analysis of hard limestone reformation and strength weakening under acidic effect

Roof disaster has always been an important factor restricting coal mine safety production.Acidic effect can reform the rock mass structure to weaken the macroscopic strength characteristics,which is an effective way to control the hard limestone roof.In this study,the effects of various factors on the reaction characteristics and mechanical properties of limestone were analyzed.The results show that the acid with stronger hydrogen production capacity after ionization(pK_(a)<0)has more prominent damage to the mineral grains of limestone.When pKa increases from−8.00 to 15.70,uniaxial compressive strength and elastic modulus of limestone increase by 117.22%and 75.98%.The influence of acid concentration is manifested in the dissolution behavior of mineral crystals,the crystal defects caused by large-scale acid action will lead to the deterioration of limestone strength,and the strength after 15%concentration reformation can be reduced by 59.42%.The effect of acidification time on limestone has stages and is the most obvious in the initial metathesis reaction stage(within 60 min).The key to the strength damage of acidified limestone is the participation of hydrogen ions in the reaction system.Based on the analytic hierarchy process method,the influence weights of acid type,acid concentration and acidification time on strength are 24.30%,59.54% and 16.16%,respectively.The research results provide theoretical support for the acidification control of hard limestone roofs in coal mines.

Valproic Acid Enhances the Anti-tumor Effect of(-)-gossypol to Burkitt Lymphoma Namalwa Cells

Burkitt lymphoma is a highly aggressive B-cell neoplasm. New therapeutic methods are needed to overcome the adverse effect of intensive chemotherapy regimens. Valproic acid and （-）-gossypol are two kinds of chemical compounds used as new anti-tumor drugs in recent years.

Differential Effects of Butyric Acid on Mouse Skin Tumorigenesis

We studied the effects of butyric acid (BA) on mouse skin tumorigenesis using chronicanimal bioassays. Topical application of BA immediately after each treatment with 12-0-te-t radecanoyl phorbol-13-acetate (TPA) promoter' inhi bi ted skint umors. The effect was depe n -dent on the dose of BA applied. BA showed no marked inhibitory effect on either skin tumorinitiation or complete tumorigenesis induced by dimet hyl benzant hracene (DMBA ). Si nce t u -mor promotion reportedly involves epigenetic events whereas tumor initiation or complete tu-morigenesis takes place through genetic pathways, it is Possible that BA exerts its antitumori-genic effects mainly by altering the epigenetic events responsible for tumor promotion. The re-sults of the study could further be used to study the mechanism of action and modification ofantitumorigenic effects of BA in combination with other substances

Temperature effect on the corrosion and passivation characterization of Ni_(82.3)Cr_7Fe_3Si_(4.5)B_(3.2) alloy in acidic media

The effects of temperature on corrosion and the electrochemical behavior of Ni82.3Cr7Fe3Si4.5B3.2 glassy alloy in HC1,H2SO4,and H3PO4 acids were studied using AC and DC techniques.Impedance data reveal that the susceptibility to localized corrosion increases with increasing temperature.Potentiodynamic polarization curves reveal that the bulk glassy alloy is spontaneously passivated at all the investigated temperature in H2SO4 and H3PO4 solutions.A localized corrosion effect in HCl solution is clearly observed.The apparent activation energies in the regions of Tafel,active,and passive,as well as the enthalpies and entropies of the dissolution process were determined and discussed.The high apparent activation energy（Ea） value for H3PO4 solution in Tafel region is explained by the low aggressivity of PO4^3- ions.

The Blocking Effect of Phenolic Acid on N-Nitrosomorpholine Formation in vitro

Phenolic acids (PAs) are widely found in many daily consumed vegetables and fruits.The inhibitory effects of PAs on Nnitrosomorpholine (NMOR) formation in vitro undersimulated gastric juice condition were studied. The results showed that the inhibjtoryIX)tency of thirteen varieties of PAs differed greatly, which may be related to theirchemical structures; the blocking rate (BR) of different killds of PAs were as follows:caf feic acid, 92.5%; tannic acid, 90.0%; gallic acid, 86.8%; sinaPinic acid, 86.2%; ferulicacid, 8l.l%; chlorogenic acid, 69.4%; gentisic acid, 69.2%; syringic acid, 62.1%; protocatechuic acid, 56.0%; p-coumaric acid, 52.5%; vannilic acid, 35.4%; moreover,p-hydroxybenzoic acid and m-coumaric acid had the least blocking effect or even slightcatalyzing effect. The results also demonstrated that amounts of NMOR formed werenegatively correlated with molar ratio of PAs to nitrite and that the optimum pH forinhibition was between 2 and 3.

Effects of caffeic acid phenethyl ester on proliferation of vascular smooth muscle cells in rats

Objective： To investigate the inhibitory effect of caffeic acid phenethyl ester（CAPE） on the proliferation of vascular smooth muscle cells （VSMC） activated by lipopolysaccharide （LPS） and to clarify its mechanism. Methods： VSMC activated by LPS （1 mg-L^-1） were treated with CAPE at different concentrations. The inhibitory effecfs of CAPE on the proliferation of VSMC were determined by methabenzthiazuron（MTT） colorimetry. The effects of CAPE on the expression of proliferating cell nuclear antigen （PCNA） and Survivin protein in VSMC were evaluated by immunocytochemistry staining technique （SABC method）. Cell cycle was analyzed by flow cytometry（FCM） with propidiumiodide （PI） labeling method. The relative expression level of Survivin mRNA was measured with real-time quantified RT-PCR technique. Results. CAPE exerted significant inhibitory effects on. proliferation of VSMC at concentrations ranging from 5 mg·L^-1 to 80 mg·L^-1, decreased the rate of cells positive for PCNA and Survivin protein and repressed the expressioh of Survivin mRNA in a dose- and time-dependent manner （P 〈 0.05）. FCM analysis displayed that CAPE up-regulated the ratio of G0/G1 stages and reduced the percentage of VSMC in S stage （P 〈 0.05）. Conclusion： CAPE can significantly inhibit the proliferation of VSMC activated by LPS in a dose- and time-dependent manner, which may be carded out through regulating cell cycle and repressing the expression of PCNA and Survivin.

THE EFFECT OF ACID TREATMENT ON THE STABILITY OF POLYMORPHS IN BETA ZEOLITE

The stability of beta zeollie in acid solution and the effect of acid treatment on the polymorphs in beta zeolite were studied. This zeolite is easily dealuminated by HCI treatment but its framework highly resistent to acidity.In β zeolite, polymorph A is less stable than polymorph B.The chirality of β zeolite can be modified by the method of acid treatment.

A role for lipids as agents to alleviate stroke damage： the neuroprotective effect of 2-hydroxy arachidonic acid

Cerebrovascular accident（CVA）or stroke is one of the world＇s leading causes of death and permanent disability.The high social and medical costs associated with this pathology mean there is an urgent need to find effective therapies.Occlusion of the middle cerebral artery（MCAO）,mainly by clots,is the origin of most CVAs in humans.

Effect of topiramate on partial excitatory amino acids in hippocampal dentate gyrus of rats after alcohol withdrawal

BACKGROUND： Many researches have indicated that the imbalances of various amino acid transmitters and neurotransmitters in brain are involved in the formation of alcohol withdrawal, especially that glutamic acid is one of the important transmitters for alcohol tolerance in central nervous system. OBJECTIVE： To observe the changes of excitatory amino acids in hippocampal dentate gyrus in rats with long-term alcohol drinking after withdrawal under consciousness, and investigate the therapeutic effect of topiramate on alcohol withdrawal. DESIGN ： A randomized control animal experiment SETTING ： Department of Neurology, Affiliated Hospital of Yanbian University MATERIALS： Thirty male Wistar rats of 4 months old, weighing 300-350 g, were purchased from the Experimental Animal Department, Medical College of Yanbian University. Topiramate was produced by Swish Cilag Company, and the batch number was 02CS063. METHODS： The experiments were carried out in the Department of Physiology, Medical College of Yanbian University from August 2005 to February 2006. ① The rats were divided randomly into three groups： control group （n=10）, alcohol group （n=10） and topiramate-treated group （n=10）. Rats in the alcohol group and topiramate-treated group were given intragastric perfusion of 500 g/L alcohol （10 mL/kg）, once a day for 4 weeks successively, and then those in the topiramate-treated group were treated with 80 mg/kg topiramate at 24 hours after the last perfusion of alcohol, once a day for 3 days successively. Rats in the control group were intragastricly given isovolume saline. ② The withdrawal symptoms were assessed at 6, 30, 48 and 72 hours after the last perfusion of alcohol by using the withdrawal rating scale set by Erden et al, which had four observational indexes of stereotyped behaviors, agitation, tail stiffness and abnormal posture, each index was scored by 5 points, the higher the score, the more obvious the symptoms. ③ The contents of aspartic acid and glutamic acid in hippocampal dentate gyrus were detected with microdialysis technique and high-performance liquid chromatograpy （HPLC） respectively at 6, 30, 48 and 72 hours after the last perfusion of alcohol in the three groups. MAIN OUTCOME MEASURES ： ① Scoring results of alcohol withdrawal symptoms; ② Changes of the contents of aspartic acid and glutamic acid in hippocampal dentate gyrus at the alcohol withdrawal symptoms, and the effects of topiramate. RESULTS： Seven rats were excluded due to inaccurate localization and natural death, and 23 rats were involved in the analysis of results. ①In the alcohol group, the scores of alcohol withdrawal symptoms at 30 and 48 hours after the last perfusion of alcohol were obviously higher than those in the control group （10.50±0.96, 14.17±1.25; 3.50±0.92, 3.16±0,31; P 〈 0.01）. In the topiramate-treated group, the scores at 30 hours after the last perfusion of alcohol （6.06±0.82, 3.50±0.92, P 〈 0.05）, and the withdrawal scores at 48 and 72 hours were close to those in the control group （4.57±0.58, 3.30±0.71; 3.16±0.31, 3.66±0.67; P 〉 0.05）.② Changes of the contents of glutamic acid in hippocampal dentate gyrus： In the alcohol group, the content of glutamic acid at 48 hours after the last perfusion of alcohol was significantly increased as compared with that at 6 hours [（143.32±11.42）%, （99.12±0.69）%; P 〈 0.05], and that at 72 hours was close to that at 6 hours [（78.50±16.40）%, （99.12±0.69）%; P 〉 0.05]. The contents of glutamic acid had no obvious differences at 6, 30, 48 and 72 hours after the last perfusion of alcohol in the topiramate-treated group [（100.30±0.37）%, （118.91±10.40）%, （99.55±12.81）%, （99.08±11.42）%; P 〉 0.05], The content of glutamic acid at 48 hours after the last perfusion of alcohol in the topiramate-treated group was obviously lower than that in the alcohol group （P 〈 0.05）, and those at 30 and 72 hours were close （P 〉 0.05）. ③ Changes of the contents of aspartic acid in hippocampal dentate gyrus： In the alcohol group, the contents of aspartic acid at 30 and 48 hours after the last perfusion of alcohol were significantly increased as compared with that at 6 hours [（126.60±8.67）%, （129.17±10.40）%, （99.25±0.87）%; P 〈 0.05], and that at 72 hours was close to that at 6 hours [（89.87±9.93）%, （99.25±0.87）%; P 〉 0.05]. The contents of aspartic acid had no obvious differences at 6, 30, 48 and 72 hours after the last perfusion of alcohol in the topiramate-treated group [（100.27±0.32）%, （120.81 ±12.63）%, （98.91±7.83）%, （85.92±8.07）%; P 〉 0.05]. The content of aspartic acid at 48 hours after the last perfusion of alcohol in the topiramate-treated group was obviously lower than that in the alcohol group （P 〈 0.05）, and those at 30 and 72 hours were close （P 〉 0.05）. CONCLUSION： ① The occurrences of alcohol withdrawal symptoms are correlated with the increased contents of excitatory amino acids in hippocampal dentate gyrus in rats. ② Topiramate can alleviate the alcohol withdrawal symptoms, which may be correlated with the decreased contents of excitatory amino acids in hippocampal dentate gyrus in rats.

Synergistic effects of brain-derived neurotrophic factor and retinoic acid on inducing the differentiation of bone marrow stromal cells into neuron-like cells in adult rats in vitro

BACKGROUND： Under induction of retinoic acid （RA）, bone marrow stromal cells （BMSCs） can differentiate into nerve cells or neuron-like cells, which do not survive for a long time, so those are restricted to an application. Other neurotrophic factors can also differentiate into neuronal cells through inducing BMSCs; especially, brain-derived neurotrophic factor （BDNF） can delay natural death of neurons and play a key role in survival and growth of neurons. The combination of them is beneficial for differentiation of BMSCs. OBJECTIVE： To investigate the effects of BDNF combining with RA on inducing differentiation of BMSCs to nerve cells of adult rats and compare the results between common medium group and single BDNF group. DESIGN： Randomized controlled animal study SETTING： Department of Neurology, Affiliated Hospital of Xuzhou Medical College MATERIALS： The experiment was carried out in the Clinical Neurological Laboratory of Xuzhou Medical College from September 2003 to April 2005. A total of 24 SD rats, of either gender, 2 months old, weighing 130-150 g, were provided by Experimental Animal Center of Xuzhou Medical College [certification： SYXK （su） 2002-0038]. Materials and reagents： low-glucose DMEM medium, bovine serum, BDNF, RA, trypsin, separating medium of lymphocyte, monoclonal antibody of mouse-anti-nestin, neuro-specific enolase, glial fibrillary acidic protein （GFAP） antibody, SABC kit, and diaminobenzidine （DAB） color agent. All these mentioned above were mainly provided by SIGMA Company, GIBCO Company and Boshide Company. METHODS： Bone marrow of SD rats was selected for density gradient centrifugation. BMSCs were undertaken primary culture and subculture; and then, those cells were induced respectively in various mediums in total of 3 groups, including control group （primary culture）, BDNF group （20 μg/L BDNF） and BDNF＋RA group （20 μg/L BDNF plus 20 μg/L RA）. On the 3^rd and the 7^th days after induction, BMSCs were stained immunocytochemically with nestin （sign of nerve stem cells）, neuron-specific enolase （NSE, sign of diagnosing neurons） and GFAP （diagnosing astrocyte）, and evaluated cellular property. MAIN OUTCOME MEASURES ： Induction and differentiation in vitro of BMSCs in 3 groups RESULTS： （1） Induction and differentiation of BMSCs： Seven days after induction, cells having 2 or more apophyses were observed. Soma shaped like angle or erose form, which were similar to neurons and glial cells having strong refraction. （2） Results of immunocytochemical detection： Three days after induction, rate of positive cells in BDNF＋RA group was higher than that in BDNF group and control group [（86.15±4.58）%, （65.43±4.23）%, （4.18±1.09）%, P 〈 0.01]. Seven days after induction, rate of positive cells was lower in BDNF group and BDNF＋RA group than that in both groups at 3 days after induction [（31.12±3.18）%, （29.35±2.69）%, P 〈 0.01]; however, amounts of positive cells of NSE and GFAP were higher than those at 3 days after induction （P 〈 0.01）; meanwhile, the amount in BDNF＋RA group was remarkably higher than that in BDNF group （P 〈 0.01）. CONCLUSION： Combination of BDNF and RA can cooperate differentiation of BMSCs into neurons and astrocyte, and the effect is superior to single usage of BDNF.

Effect of exogenous salicylic acid on resistance of rice seedlings to blast

Salicylic acid(SA)is an endogenous regulatorymolecule for plant flowering and thermogene-sis,and has been reported as a signal moleculeof plant disease resistance in the plant-pathogen interaction.Exogenous SA is capableof inducing disease resistance in a wide range ofplants.This study was to evaluate the poten-tial for SA to induce resistance of rice seedlings

Effect of acidity on morphologies and photodimerization kinetics in Langmuir-Blodgett monolayers of styrylquinoline derivatives

The real-time second harmonic generation was employed to investigate the[2＋2]photodimerization of styrylquinoline（SQ） derivatives in Langmuir-Blodgett（LB） monolayers deposited from aqueous subphases with different acidity.It was discovered that the photodimerization rate constant significantly decreased upon the addition of acid.The additional atomic force microscopy measurements revealed that surface morphologies were correlated to the photodimerization kinetics.These experimental results provide direct evidence for the topo-chemical mechanisms of[2＋2]photodimerization in LB films.The current study demonstrates that the intermolecular interactions and aggregation structures play important roles in the photochemical properties at surfaces.

Controls of Acid-sensitive Minerals on Reservoir Sensitivity Testing： An Example from the Silurian Kepingtage Formation in Tazhong Area, Tarim Basin

The Silurian Kepingtage Formation in Tazhong area is regarded as an acid-sensitive hydrocarbon reservoir. However, formation mechanism of acid-sensitive of the reservoir cannot be interpreted by the existing acid-sensitive evaluation criterion based on damage rate. The contents of acid-sensitive minerals illustrated by bulk-rock XRD, scanning electron microscopy and clay mineral composition analysis exert the dominant control on acid-sensitive flow testing of the reservoir. The ironbearing minerals（including pyrite cements and chlorite cements） mainly deteriorate reservoir quality, while the iron-free minerals（including calcite cements and dolomite cements） mainly improve permeability. The permeability variation of the tested samples is controlled by the relative content of two acid-sensitive minerals. On the basis of newly established sensitivity mechanism and its influence on permeability, the corresponding ion（Fe^（2＋）） stabilizer was added to the acidizing fluids during the acidification reconstruction, which inhibited the negative factors of acid-sensitive minerals and improved the target layer quality effectively.

Gold-iridium catalysts for the hydrogenation of biomass derived products

Au-Ir and Au-Ru on TiOz catalysts prepared by sequential deposition-precipitation technique were compared with the corresponding monometallics in the hydrogenation of levulinic acid to y-valero]actone. Interestingly the addition of Ao to Ir/TiO2 showed a detrimental effect on the activity of Ir monometallic catalyst whereas a positive synergistic effect was shown in the case of Ru. Both catalysts were reduced under H2 to increase the M0-Au0 interaction, From previous DFT calculations and catalytic test, we addressed the lower activity of Au-lr/TiO2 than that of Ir/TiO2 to the interference of Au into the redox mechanism of lr atoms.

Influence of Mg/Al Molar Ratio on the Structures and Properties of Ru-Mg Alx Catalysts for Isomerization Linoleic Acid

With the knowledge on the significant effect of basic site and Ru on the catalytic performance of heterogeneous catalysts in the isomerization of linoleic acid to conjugated linoleic acid,a series of Ru-Mg Alx compounds with different basicity have been prepared by controlling the Mg/Al molar ratio. The results showed the catalysts with different basicity markedly influence the structure,the Ru dispersion,properties and catalytic performances for the isomerization reaction. The strong basic site is conductive to the high yield of CLA products. The strong basic site and the well-dispersion RuO2synergetic catalysis for the isomerization reaction,basic site and the well-dispersion RuO2synergetic effect are possibly via a Mg-O-Ru linkage.

Effect of Medium Acidity and Photostability of 3-（4-Dimethyl- amino-phenyl）-l-（2,5-dimethyl-thiophen-3-yl）-propenone （DDTP）： A New Green Emitting Laser Dye

On the line of a previous work on the spectral properties of some of heteroaryl chalcone, the effect of medium acidity and photoreactivity of 3-（4-dimethylamino-phenyl）-l-（2,5-dimethyl-thiophen-3-yl）-propenone （DDTP） has been investigated in dimethylformamide and in chloromethane solvents such as methylenechloride, chloroform and carbon tetrachloride. The dye solution （ca. 5×10^-4 mol·L^-1 in DMF） gives a good laser emission in the range 470 --560 nm with emission maximum at 515 nm upon pumping by nitrogen laser （λex=337.1 nm）. The laser parameters such as gain coefficient （a）, emission cross section （Cre） and half life energy （E1/2） at maximum laser emission are also determined.

Temperature effect on photolysis decomposing of perfluorooctanoic acid

Perfluorooctanoic acid（PFOA）is recalcitrant to degrade and mineralize.Here,the effect of temperature on the photolytic decomposition of PFOA was investigated.The decomposition of PFOA was enhanced from 34% to 99% in 60 min of exposure when the temperature was increased from 25 to 85℃ under UV light（201–600 nm）.The limited degree of decomposition at 25℃ was due to low quantum yield,which was increased by a factor of 12 at 85℃.Under the imposed conditions,the defluorination ratio increased from 8% at 25℃ to 50% at85℃ in 60 min.Production of perfluorinated carboxylic acids（PFCAs,C7–C5）,PFCAs（C4–C3）and TFA（trifluoroacetic acid,C2）accelerated and attained a maximum within 30 to 90 min at 85℃.However,these reactions did not occur at 25℃ despite extended irradiation to180 min.PFOA was decomposed in a step-wise process by surrendering one CF2unit.In each cyclical process,increased temperature enhanced the quantum yields of irradiation and reactions between water molecules and intermediates radicals.The energy consumption for removing eachμmol of PFOA was reduced from 82.5 k J at 25℃ to 10.9 k J at 85℃ using photolysis.Photolysis coupled with heat achieved high rates of PFOA degradation and defluorination.

Effect of water vapor on NH_3–NO/NO_2 SCR performance of fresh and aged MnO_x–NbO_x–CeO_2 catalysts

A MnOx-NbOx-CeO2 catalyst for low temperature selective catalytic reduction（SCR） of NOx with NH3 was prepared by a sol-gel method, and characterized by NH3-NO/NO2 SCR catalytic activity, NO/NH3 oxidation activity, NOx/NH3 TPD, XRD, BET, H2-TPR and in-situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy（DRIFTS）. The results indicate that the Mn Ox-Nb Ox-CeO2 catalyst shows excellent low temperature NH3-SCR activity in the temperature range of 150-300℃. Water vapor inhibits the low temperature activity of the catalyst in standard SCR due to the inhibition of NOx adsorption. As the NO2 content increases in the feed, water vapor does not affect the activity in NO2 SCR. Meanwhile, water vapor significantly enhances the N2 selectivity of the fresh and the aged catalysts due to its inhibition of the decomposition of NH4NO3 into N2O.