Effect of mono-/divalent metal ions on the conductivity characteristics of DNA solutions transferring through a microfluidic channel

Interactions between deoxyribonucleic acid(DNA) and metal ions are vital for maintaining life functions, however,there are still unsolved questions about its mechanisms. It is of great practical significance to study these issues for medical chip design, drug development, health care, etc. In this investigation, the conductivity properties of λ-DNA solutions with mono-/divalent metal ions(Na+, K^(+), Mg^(2+), and Ca^(2+)) are experimentally studied as they are electrically driven through a 5 μm microfluidic channel. Experimental data indicate that the conductivities of λ-DNA solutions with metal ions(M+/M2+) basically tend to reduce firstly and then increase as the voltage increases, of which the turning points varied with the metal ions. When the voltage surpasses turning points, the conductivity of λ-DNA-M+solutions increases with the concentration of metal ions, while that of λ-DNA-M^(2+)solutions decrease. Moreover, the conductivity of λ-DNA-M^(2+)solutions is always smaller than that of λ-DNA-M+solutions, and with high-concentration M^(2+), it is even smaller than that of the λ-DNA solution. The main reasons for the above findings could be attributed to the polarization of electrodes and different mechanisms of interactions between metal ions and λ-DNA molecules. This investigation is helpful for the precise manipulation of single DNA molecules in micro-/nanofluidic space and the design of new biomedical micro-/nanofluidic sensors.

Feasibility investigation on deep ocean compact autonomous Raman spectrometer developed for in-situ detection of acid radical ions

A newly developed Deep Ocean Compact Autonomous Raman Spectrometer （DOCARS） system is introduced and used for in-situ detection of acid radical ions in this paper. To evaluate the feasibility and capability of DOCARS for quantitative analysis of the acid radical ions in the deep ocean, extensive investigations have been carried out both in laboratory and sea trials during the development phase. In the laboratory investigations, Raman spectra of the prepared samples （acid radical ions solutions） were obtained, and analyzed using the method of internal standard normalization in data processing. The Raman signal of acid radical ions was normalized by that of water molecules. The calibration curve showed that the normalized Raman signal intensity of SO4^2-, NO3^-, and HCO^-3 increases linearly as the concentration rises with correlation coefficient R^2 of 0.99, 0.99, and 0.98 respectively. The linear function obtained from the calibration curve was then used for the analysis of the spectra ,data acquired in the sea trial under a simulating chemical field in the deep-sea environment. It was found that the detected concentration of NO3 according to the linear function can reflect the concentration changes of NO~ after the sample was released, and the detection accuracy of the DOCARS system for SO^2-_4 is 8%. All the results showed that the DOCARS system has great potential in quantitative detection of acid radical ions under the deep-sea environment, while the sensitivity of the DOCARS system is expected to be improved.

Nerve growth factor in muscle afferent neurons of peripheral artery disease and autonomic function

In peripheral artery disease patients,the blood supply directed to the lower limbs is reduced.This results in severe limb ischemia and thereby enhances pain sensitivity in lower limbs.The painful perception is induced and exaggerate during walking,and is relieved by rest.This symptom is termed by intermittent claudication.The limb ischemia also amplifies autonomic responses during exercise.In the process of pain and autonomic responses originating exercising muscle,a number of receptors in afferent nerves sense ischemic changes and send signals to the central nervous system leading to autonomic responses.This review integrates recent study results in terms of perspectives including how nerve growth factor affects muscle sensory nerve receptors in peripheral artery disease and thereby alters responses of sympathetic nerve activity and blood pressure to active muscle.For the sensory nerve receptors,we emphasize the role played by transient receptor potential vanilloid type 1,purinergic P2X purinoceptor 3 and acid sensing ion channel subtype 3 in amplified sympathetic nerve activity responses in peripheral artery disease.

Performance of Metal and Acid Ions Remediation in Contaminated Soils by Electrokinetics with Chitosan Permeable Reactive Barrier

Metal and acid ions contamination of soil in China is serious. To find an efficient solution for remediating the combined pollution,electrokinetics( EK) coupled with chitosan( CTS)permeable reactive barrier( EK/CPRB) was used to investigate the performances of metal and acid ions remediation. Adsorption characteristics of Zn^(2+),Fe^(3+),Ca^(2+),SO_4^(2-) and NO_3^- onto CTS were also conducted. The results showed the sorption of Zn^(2+),Fe^(3+),Ca^(2+),SO_4^(2-) and NO_3^- on CTS could be well described by Freundlich model. When the CTS dosage is 8 g,the total removal efficiency for Zn^(2+),Fe^(3+),Ca^(2+),SO_4^(2-) and NO_3^- is 86. 8%,90. 2%,92. 4%,90. 0% and 82. 5%,respectively. CTS enhanced ions remediation efficiencies significantly compared with the single EK system,especially for SO_4^(2-) and NO_3^-. The results indicate EK/CPRB system is suitable for the remediation of soil contaminated by both metal ions and acid ions.

An evaluation of quality assurance to monitor acid precipitation by using ion balance in Guizhou，China

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RADICAL POLYMERIZATION OF VINYL MONOMER INITIATED BY CERIC ION/TARTARIC ACID

The polymerization of acrylamide and acrylonitrile using ceric ion as initiator can be promoted greatly by the tartaric acid. The kinetics of acrylamide polymerization initiated by ceric ion/tartaric acid has been studied. The presence of the species of tartaric acid in Polyacrylonitrile produced by using ceric ion/tartaric acid as niitiator has been confirmed by FT-IR analysis.

Tb(lll) and Ca(ll) Ion Equilibria in the Presence of Glutamic Acid and Glutamine

Tb(111) and Ca(11) ion equilibria in the presence of glutamic acid and glutamine were studied by potentiometric titration at 37'C and an ionic strength of 0. 15mol/L(NaCl) .The stability constants for Tb(111) and Ca(11)complexes in the systems were obtained. The species and their distribution in the systems were discussed.

Detrimental role of residual surface acid ions on ozone decomposition over Ce-modified γ-MnO2under humid conditions

In the study,the catalyst precursors of Ce-modifiedγ-MnO2 were washed with deionized water until the pH value of the supernatant was 1,2,4 and 7,and the obtained catalysts were named accordingly.Under space velocity of 300,000 hr-1,the ozone conversion over the pH=7 catalyst under dry conditions and relative humidity of 65%over a period of 6 hr was 100%and 96%,respectively.However,the ozone decomposition activity of the pH=2 and 4 catalysts distinctly decreased under relative humidity of 65%compared to that under dry conditions.Detailed physical and chemical characterization demonstrated that the residual sulfate ions on the pH=2 and 4 catalysts decreased their hydrophobicity and then restrained humid ozone decomposition activity.The pH=2 and 4 catalysts had inferior resistance to high space velocity under dry conditions,because the residual sulfate ion on their surface reduced their adsorption capacity for ozone molecules and increased their apparent activation energies,which was proved by temperature programmed desorption of O2 and kinetic experiments.Long-term activity testing,X-ray photoelectron spectroscopy and density functional theory calculations revealed that there were two kinds of oxygen vacancies on the manganese dioxide catalysts,one of which more easily adsorbed oxygen species and then became deactivated.This study revealed the detrimental effect of surface acid ions on the activity of catalysts under humid and dry atmospheres,and provided guidance for the development of highly efficient catalysts for ozone decomposition.

Fast removal of heavy metal ions and phytic acids from water using new modified chelating fiber

The graft copolymerization of acrylic acid（AA） onto polyethylene glycol terephthalate（PET） fiber initialed by benzoy peroxide （BPO） was carried out in heterogeneous media.Moreover,modification of the grafted PET fiber（PET-AA） was done by changing the carboxyl group into acylamino group through the reaction with dimethylamine.The modified chelating fiber（NDWJN1） was characterized using elementary analysis,SEM and FT-IR spectroscopy.Adsorption kinetic curves indicated that NDWJNl could fast remove heavy metal ions and phytic acids from water effectively.Furthermore,batch kinetic studies indicated that heavy metal ions adsorbed to NDWJNl could be filted well by both pseudo-first-order and pseudo-second-order adsorption equations,but the intra-particle diffusion played a dominant role in the adsorption of phytic acids.

Protein and RNA expression of acid-sensing ion channels 2 and 3 in myocardial ischemia rats induced by isoproterenol

OBJECTIVE:To investigate the impact of electro-acupuncture at the Neiguan(PC 6) acupoint on protein and RNA expression of acid-sensing ion channel 2(ASIC2) and ASIC3 in myocardial ischemia rats.METHODS:Fifty male Sprague-Dawley rats were used,weighing(230 ± 50) g.The rats were randomized into a normal group A,model group B,Neiguan(PC 6) group C,Lieque(LU 7) group D,and A-shi points group E.There were 10 rats in each group.Rats were continuously administered 85 mg/kg intravenous isoproterenol daily to establish the model.Successfully modeled rats in groups C,D,and E were given electro-acupuncture treatment.Each group of rats was sacrificed with chloral hydrate(1 mL/100 g) intraperitoneal injection.The left ventricular myocardium was extracted and placed at- 70 ℃ until use.Western blot analysis and real-time PCR were performed to assay protein and RNA expressions of ASIC2 and ASIC3,respectively.Fold changes in RNA expression were quantified with the 2~^(-△△Ct) method.Blood samples were drawn from the aorta abdominalis and tested for creatine kinase-MB(CK-MB) and lactate dehydrogenase(LDH) levels using enzyme-linked immunosorbent assay.RESULTS:Myocardial ischemia rats given electro-acupuncture at the Neiguan(PC 6) acupoint had significantly lower protein and RNA expression of ASIC2 and ASIC3,and CK-MB and LDH levels,compared with model rats(P < 0.01).CONCLUSION:Electro-acupuncture at the Neiguan(PC 6) acupoint can not only decrease the protein and RNA expression of ASIC2 and ASIC3,but also inhibit the opening of ASICs and reduce the cardiomyocyte damage in myocardial ischemia rats.

Determination of iminodiacetic acid in the glyphosate by ion chromatography

In this paper,a simple method based on ion chromatography（IC） with conductivity detection was developed for the determination of iminodiacetic acid（IDA） in the herbicide of glyphosate.Under optimized chromatographic conditions,good linear relationship,sensitivity and reproducibility were obtained.The detection limit（LOD） for IDA obtained by injecting 25 μL of sample was 31.8 μg/L（S/N = 3）.Relative standard deviation（RSD） of repeated analysis for the peak areas was less than 1.53%（n = 6）.A spiking study was performed with satisfactory recoveries between 92.8%and 103.6%.It was confirmed that this method could be applied in glyphosate products.