Addition Of Sodium Salicylate Research Articles

One-Pot Synthesis of Silicon Quantum Dots-Based Fluorescent Nanomaterial and Its Application.

Conventionally obtained silicon quantum dots (Si QDs) generally suffer from the disadvantages of a cumbersome preparation process, large fluctuation in the quality of Si QDs, poor water solubility, and aggregation-caused quenching (ACQ) phenomenon. Here we report a facile one-pot strategy to synthesize a novel Si QDs-based fluorescent nanomaterial in which Si QDs are confined into dendritic mesoporous silica, named as SiQDs@DMSNs. The prepared SiQDs@DMSNs, with adjustable particle sizes ranging from 140 to 300 nm, emit blue fluorescence around 410 nm upon excitation by ultraviolet light at a wavelength of 300 nm. It is found that the addition of sodium salicylate (NaSAL) plays a crucial role in the in situ generation of Si QDs. The obtained SiQDs@DMSNs exhibit excellent fluorescence intensity, water solubility, and stability, facilitating easy surface modification, without being limited by the ACQ phenomenon. It is expected to be widely used in many fields such as biosensors, nanomedicines, in vivo imaging, fingerprint identification, and anticounterfeiting labels.

Effects of sodium salicylate on the determination of Lead-210/Bismuth-210 by Cerenkov counting

Due to the nature of Cerenkov radiation and instrumental limitations, detection efficiencies of 210Bi by Cerenkov counting are generally quite low (~15%). Sodium salicylate, acting as a wavelength shifter, has been used to improve the detection efficiency of Cerenkov photons. In this study, we found that the addition of sodium salicylate could significantly increase the counting efficiencies of 210Pb/210Bi in aqueous samples. Meanwhile, a sharp increase of the counting efficiency for the alphas from 210Po was also observed with the addition of high concentration of sodium salicylate, implying that scintillation light rather than Cerenkov photons from the alphas has been produced. Detailed studies about the effects of sodium salicylate on the counting of 210Pb, 210Bi and 210Po were conducted. At low concentration (< 0.5 mg g-1) of sodium salicylate, only a small increase in Cerenkov counting efficiency for 210Bi by the wavelength-shifting effect could be observed. Meanwhile, the counting efficiency for 210Bi at high concentration (> 1 mg g-1) of sodium salicylate would significantly increase due to the scintillation effect.

Heat transfer and CHF in subcooled flow boiling of aqueous surfactant solutions

Flow boiling heat transfer characteristics of surfactant solution was studied and compared to that of pure water. The tested fluid was an aqueous solution of cetyltrimethyl ammonium chloride (CTAC) with addition of sodium salicylate (NaSal) at the same mass concentration. Tests were performed with 6.0 × 3.5 mm cross-section channel over flow rate range of 192–403 ml/min, at inlet temperature of 80 °C and an outlet pressure of 101.3 kPa. Liquid column method and resistance method of temperature determination were adopted to obtain accurate experimental data. The present experimental results show that, the flow boiling in CTAC/NaSal solutions at an appropriate concentration (100 ppm, ppm refers to part per million) behaved a good flow boiling performance. The heat transfer coefficient of 100 ppm CTAC/NaSal solution at the critical heat flux (CHF) was increased to 1.36 times compared to that of pure water. Besides, the CHF of 0.08 mm thick Nickel foil was increased to about 126% by surfactant addition when the concentration was beyond 100 ppm. The addition of CATC/NaSal increased the nucleation site density and inhibits bubble coalescence which were likely to be causes of enhancing the boiling heat transfer coefficient and CHF of subcooled flow boiling of CATC/NaSal aqueous solutions.

Experimental study on the characteristics of CHF and pressure fluctuations of surfactant solution flow boiling

The critical heat flux (CHF) and presure fluctuation characteristics of surfactant solution flow boiling were studied experimentally and compared to that of pure water. The tested fluid was an aqueous solution of cetyltrimethyl ammonium chloride (CTAC) with addition of sodium salicylate (NaSal) at the same mass concentration. Tests were performed in a flow channel with 6.0×3.5mm cross-section over flow rate range of 192–406ml/min, at 80°C inlet temperature and 101.3kPa outlet pressure. The present experimental results show that, the CTAC/NaSal solutions behave an increased CHF: the value of CHF kept nearly constant at a level about 1.26 times of that of pure water when the solution concentration was beyond 100ppm (ppm: part per million). And the CTAC/NaSal solution had stronger pressure fluctuations than water. Visualization of the flow boiling process shows that bubbles in CTAC/NaSal solution have smaller diameters and larger population density than that in water, which may be the reason of higher CHF for surfactant solution case. And the bubbles in CTAC/NaSal solution existed for a longer time than in water, which was about ten times of the bubbles in water. These bubbles increased flow velocity and enhanced disturbances, which may be another reason of flow boiling heat transfer enhancement and stronger pressure fluctuations.

Bubble explosion in pool boiling around a heated wire in surfactant solution

This paper reports a new pool boiling phenomenon of bubble explosion in a surfactant solution. The working fluid was an aqueous solution of cetyltrimethyl ammonium chloride (CTAC) with addition of sodium salicylate (NaSal) at the same mass concentration. A platinum wire was horizontally placed in the fluid for heating. The boiling heat transfer performances of the tested fluid at fluid temperature (288.15K) and different concentrations of CTAC/NaSal solution (0–400ppm) have been presented. It’s found that the tested surfactant solution significantly augmented boiling heat transfer as compared with water, and the best heat transfer performance was found at the concentration ranging from 5 to 100ppm. With a high-speed camera and an inverted microscope, the nucleation boiling process on the heated wire was recorded. For the first time, we observed a new bubble explosion phenomenon around the heated wire in CTAC/NaSal solutions (at concentration beyond 0.1ppm), which is apparently different from the previously reported boiling explosion due to homogeneous nucleation. Together with the observed strong jet-flow behaviors, bubble explosion strengthened the local disturbance and enhanced the boiling heat transfer. It was conjectured that the strong jet-flow phenomenon is essentially the traces of small bubbles and bubble explosion is a failed coalescence of unstable bubbles, which leads to the disturbance and boiling heat transfer enhancement.

Improved heat transfer and flow resistance achieved with drag reducing Cu nanofluids in the horizontal tube and built-in twisted belt tubes

Experimental studies were performed to investigate drag reducing nanofluids’ convective heat transfer coefficient and flow resistance coefficient at Reynolds numbers ranging from 2000 to 18000. Added 0–0.5% mass fraction of Cu nanoparticles into a concentration of 100–400mg·kg−1 cetyl trimethyl ammonium chloride (CTAC), which is a drag reducing fluid. The ratio of two kinds of fluids was explored to find a suitable composition and preparation to define their overall convective heat transfer and flow characteristics. Results indicated that the addition of sodium salicylate (NaSal) in CTAC with deionized water creates an improved drag reducing fluid with stability. When the drag reducing fluid concentration reached 200mg·kg−1, it reached its optimum drag reducing performance in horizontal tube experiments. Experiments with built-in twisted belt tubes resulted in a much improved convective heat transfer characteristic. Results showed using drag reducing Cu nanofluids the heat transfer coefficient will be approximately twice as large as that found in a horizontal tube and the flow resistance coefficient is approximately ten times greater. However, even though built-in twisted belt tubes can enhance heat transfer, they also increase flow resistance. Heat transfer and flow resistance correlations of the drag reducing Cu nanofluids in a horizontal tube and built-in twisted belt tubes were compared with final results showing the calculated and experimental values to be in good agreement. When Cu nanoparticle mass fraction is 0.4%, drag reducing Cu nanofluid has the best heat transfer and drag reducing characteristics. Finally, the overall K factor performance were greater than 1 at different concentrations, which indicated their convective heat transfer enhancing effect was stronger than the reducing flow resistance effect so that they can be used to solve the problem of heat transfer deterioration for drag reducing fluids.

Rheological response and small-angle neutron-scattering study of diester-bonded cationic biodegradable gemini surfactants in presence of different additives

Morphological changes and internal packing arrangements of planar dicationic-ester-bonded biodegradable gemini surfactants ethane-1, 2-diyl-bis(N,N-dimethyl-N-alkylammonium acetoxy) dichlorides (m-E2-m) have been explored by exploiting small-angle neutron-scattering (SANS) measurements. The data have been analyzed on the basis of Hayter and Penfold model for macroion solutions to obtain information about the aggregation behavior at the molecular level. The extent of micellar growth and structural changes of the micelles formed by these surfactants have been found to depend on the number of methylene units in their tail length. The growth and variation of micellar shape are more pronounced for the surfactant with longer tail length (m = 16), whereas the surfactants with shorter tail length showed less variation of these properties in aqueous solution. Semi-major axes of the micelles show flexibility while varying the concentration and temperature of the systems; however, semi-minor axes remain rigid. Changes in the structural parameters of the micelles with addition of different salts were also inferred from SANS measurements. The intensity of scattered neutrons at the low Q region was found to increase while varying the nature of salt from monovalent to trivalent. On the basis of rheological responses, the rich aggregation behavior resulting from the addition of sodium salicylate (NaSal) is attributed to the special molecular structure of the gemini surfactant and the appropriate interaction between the surfactant and NaSal. This is inferred on the basis of behavior observed by varying the chain length (m) of the gemini surfactant that resulted in the formation of different types of microstructures.

Heat transfer in the thermal entrance region for drag reduction surfactant solutions in pipe flow

Experimental results relating to heat transfer for a flow of surfactant solutions in the thermal entrance region of a pipe were discussed. Aqueous solutions of hexadecyltrimethylammonium chloride with addition of sodium salicylate were used as model fluids. It was observed that the effect of buoyancy on the heat transfer process was less pronounced in the entrance region of a pipe than in the scope of a fully developed flow. It was demonstrated that it was possible to correlate experimental results for the flow of drag-reducing surfactant solutions, based on the dependence of Nusselt number on a dimensionless longitudinal coordinate. In addition, simple empirical equations were proposed which enable the local and mean values of the heat transfer coefficient to be calculated.

Flow of drag-reducing surfactant solutions in rough pipes

The paper reports the results of experimental study of the flow of hexadecyltrimethylammonium chloride (CTAC) solutions with addition of sodium salicylate (NaSal) in the rough pipes. Measurements were performed in the range of the surfactant concentration from 200 to 400 ppm at a constant molar ratio CTAC/NaSal of 1:2. Five pipes of the relative roughness k/ D varying from 1.2 × 10 −2 to 5.6 × 10 −2, obtained by the covering of inner surface of the pipes with glued silicon carbide particles of different size, were studied. The roughness was observed to increase the drag of flow of CTAC/NaSal solutions already at Reynolds numbers higher than 800. With increasing relative roughness k/ D, the critical value of Reynolds number, at which the drag reduction disappears, was found to decrease. However, no influence of the roughness on the critical shear stress was noted. The ratio of the critical Reynolds number for rough pipes to that of hydraulically smooth pipes was independent of the surfactant concentration. The degree of drag reduction by the flow of surfactants was greater in rough pipes than in smooth pipes.

Effect of Sodium Salicylate on the Properties of Gemini Surfactant Solutions

AbstractIn this paper, the effect of sodium salicylate on the solution properties of a gemini surfactant, butylidene‐α, ω‐bis (cetyl dimethyl ammonium bromide), was investigated through absorbance and dynamic light scattering (DLS) measurement, transmission electron microscope (TEM) observation, and rheology measurement. The DLS experiment showed that the average size of aggregates increases with the addition of sodium salicylate. The TEM experiment showed that the addition of sodium salicylate causes the change of the size and shape of aggregate. With the increase of the concentration of sodium salicylate, the viscosity of the gemini surfactant solution reaches a maximum value and the flow pattern of the gemini surfactant solution also undergoes a great change with a transition from a Newtonian fluid to a non‐Newtonian fluid.

Radium-228 analysis of natural waters by Cherenkov counting of Actinium-228

The activities of 228Ra in natural waters were determined by the Cherenkov counting of the daughter nuclide 228Ac. The radium was pre-concentrated on MnO 2 and the radium purified via ion exchange and, after a 2-day period of incubation to allow for secular equilibrium between the parent–daughter 228Ra( 228Ac), the daughter nuclide 228Ac was isolated by ion exchange according to the method of Nour et al. [2004. Radium-228 determination of natural waters via concentration on manganese dioxide and separation using Diphonix ion exchange resin. Appl. Radiat. Isot. 61, 1173–1178]. The Cherenkov photons produced by 228Ac were counted directly without the addition of any scintillation reagents. The optimum Cherenkov counting window, sample volume, and vial type were determined experimentally to achieve optimum Cherenkov photon detection efficiency and lowest background count rates. An optimum detection efficiency of 10.9±0.1% was measured for 228Ac by Cherenkov counting with a very low Cherenkov photon background of 0.317±0.013 cpm. The addition of sodium salicylate into the sample counting vial at a concentration of 0.1 g/mL yielded a more than 3-fold increase in the Cherenkov detection efficiency of 228Ac to 38%. Tests of the Cherenkov counting technique were conducted with several water standards of known activity and the results obtained compared closely with a conventional liquid scintillation counting technique. The advantages and disadvantages of Cherenkov counting compared to liquid scintillation counting methods are discussed. Advantages include much lower Cherenkov background count rates and consequently lower minimal detectable activities for 228Ra and no need for expensive environmentally unfriendly liquid scintillation cocktails. The disadvantages of the Cherenkov counting method include the need to measure 228Ac Cherenkov photon detection efficiency and optimum Cherenkov counting volume, which are not at all required when liquid scintillation analysis is used.

Salicylate Activity. 2. Potentiation of Atrazine

Atrazine [6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine] inhibits photosystem II (PSII) and is commonly used to control weeds in maize. It has been found that addition of sodium salicylate (sodium 2-hydroxybenzoate; NaSA) increased the postemergence herbicidal activity of atrazine against dicotyledonous weeds. NaSA also potentiated the activity of bentazon, another PSII-inhibiting herbicide. NaSA increased atrazine activity when applied either as a tank mix or up to 96 h prior to atrazine application. Other salicylates and the plant disease resistance inducers acibenzolar-S-methyl [benzo-(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester] and 2,6-dichloroisonicotinic acid also increased atrazine activity. Among the compounds tested, 3-chloro-5-fluorosalicylate, 4-chlorosalicylate, or 2,6-dichloroisonicotinic acid combined with atrazine yielded the greatest increase in herbicidal activity. Potentiation of atrazine by NaSA was greater at higher temperatures (35 and 25 > 15 degrees C). Also, greater potentiation was observed as the light level decreased. In darkness, NaSA alone or in combination with atrazine caused plant death, whereas atrazine alone had little effect. NaSA increased atrazine activity on npr1-2, an Arabidopsis mutant compromised in SA-induced disease resistance. Atrazine activity was also potentiated by NaSA on the ethylene insensitive mutant ein2-1. This indicates that atrazine potentiation is independent of either salicylate-induced disease resistance or ethylene perception.

Salicylate Activity. 1. Protection of Plants from Paraquat Injury

Paraquat (1,1'-dimethyl-4,4'-bipyridinium; methylviologen) is a widely used, nonselective contact herbicide that rapidly stimulates free radical generation. It has been found that the addition of sodium salicylate (sodium 2-hydroxybenzoate; NaSA) to paraquat spray solutions significantly decreased herbicidal activity. This protection was observed in tobacco (Nicotiana tabacum) regardless of whether NaSA was foliar-applied along with or prior to paraquat application or NaSA was soil-applied prior to paraquat application. Because salicylic acid (SA) is an inducer of systemic acquired resistance (SAR) to plant disease, paraquat protection by three SAR inducers (acibenzolar-S-methyl, harpin, and probenazole) and selected salicylate derivatives was assessed. Twenty-two of 24 compounds tested decreased herbicidal activity when foliar-applied with paraquat. Protection from paraquat was greatest with 5-chlorosalicylate, and no protection was observed with benzoic acid. NaSA decreased paraquat activity on npr1-2, an Arabidopsis mutant that is compromised in NaSA-induced SAR, and on ein2-1, an ethylene-insensitive Arabidopsis mutant. Thus, salicylate protection from paraquat is independent of disease resistance and ethylene perception. This suggests the existence of an NaSA-mediated pathway capable of protecting plants from reactive oxygen stress.

Prestin is the Best One, for Audition

Hair cells convert acoustic information into electrical signals that are processed by the brain. These cells also elongate and shorten in response to the electronic signals they generate. The motor protein that drives this cellular shape change has gone undetected until now. Zheng et al . used subtractive hybridization to identify a candidate motor gene termed Prestin . Ectopic expression of Prestin protein in a kidney cell line exhibited charge movement when measured as transient capacitive current. This current was blocked by the addition of sodium salicylate, an agent known to block capacitive current in hair cells. Expression of an anion transport protein, Pendrin, which has a high level of sequence similarity to Prestin, in kidney cells did not lead to capacitance, suggesting that current capacitance was not, in general, the consequence of overexpressing any anion transporter. The authors also demonstrated that expression of Prestin in kidney cells could evoke a change in cell motility (and shape), giving further evidence that Prestin is the likely protein motor in auditory hair cells. An accompanying news &amp; views by Holley summarizes the research and discusses its implications. Zheng, J., Shen, W., He, D.Z.Z., Long, K.B., Madison, L.D., and Dallos, P. (2000) Prestin is the motor protein of cochlear outer hair cells. Nature 405 : 149-155. [Online Journal] Holley, M. (2000) Tuning in with motor proteins. Nature 405 : 130-133. [Online Journal]

The Alignment of Lyotropic Liquid Crystals Formed by Hexadecyltrimethylammonium Bromide in D2O in a Magnetic Field

The alignment of lyotropic liquid crystals formed by hexadecyltrimethylammonium bromide (CTAB, where C stands for cetyl) with D2O was studied by the use of 2H NMR. At CTAB/D2O concentrations between 1.01 and 1.29 mol/kg, liquid crystal domains aligned in the magnetic field within a few hours. The dependence of the characteristic alignment time on concentration and temperature has been determined. At higher concentrations, no alignment took place due to the high viscosity of the system. At lower concentrations, the alignment could not be observed by 2H NMR. The addition of sodium salicylate (NaSal), at equal molar concentrations of CTAB and NaSal, changed the orientation of the micelles from parallel to the magnetic field to perpendicular to the field. Line-shape simulations were carried out to give estimates on the rate of exchange between free D2O molecules and those bounded to the micelles, as well as on the deuterium quadrupole splittings for D2O molecules bound to micelles. The dependence of the characteristic alignment time on the strength of magnetic field was also studied.

Transformation of wild type Klebsiella pneumoniae with plasmid DNA by electroporation

Attempts to transform wild-type strains of Klebsiella pneumoniae using the electroporation method resulted in very low efficiencies. Transformation assays performed with plasmid pBR328 resulted in 10 4 transformants/μg DNA using a fresh isolate of K. pneumoniae, and only with bacteria harvested at the beginning of the growth curve (≈10 8 CFU/ml). This low efficiency is presumably due to the presence of bacterial exopolysaccharides. We investigated the effect of substances reducing polysaccharide production on the electroporation efficiency. Addition of sodium salicylate (187 mM), bismuth subsalicylate (0.25 mM) or ethylene glycol bis (2-aminoethyl ether) tetraacetate (EGTA) (0.4 mM) to the culture medium had no or little effect upon transformation effeciencies. However, up to 10 8 transformants/μg DNA were obtained by adding 0.7 mM of ethylene diamine tetra acetate (EDTA) to the culture medium and harvesting bacteria in the early growth phase.

90 EFFECT OF SODIUM SALICYLATE ON INSULIN SECRETION: STUDIES ON THE MECHANISM OF ACTION

The curve that depicts the inter-relation of different glucose concentrations(5.5 to 27.5mM) to the insulin response is shifted to the left by the addition of sodium salicylate(1.87mM) when incubation of pancreas slices are used. Phentolamine but not sodium salicylate, overcomes the inhibitory effect of epinephine on insulin secretion induced by glucose. The highest insulin response is obtained by theophylline or pentoxyfilline at 10mM concentrations (in the presence of glucose 11mM). When sodium salicylate is present in the incubation medium, only 5 mM theophylline or pentosyfine plus 11 mM glucose achives the highest insulin response. Salicylate lower the free tubulin pool an action that is impaired by imidazole; however imidazole does not impaire the effect of A23187. The results shown suggest: a) sodium salicylate increases beta cell sensitivity to glucose, b) adrenergic tone modifications are not related to the salicylate mechanism of action c) an increment in the cAMP production seems to be the main way by which salicilate increases insulin secretion, d) the effect of salicylate on the microtubular system are indirect and mediated through an increment of the pancreatic cAMP.

A rapid method for the determination of sodium in serum.

A colorimetric method for the determination of serum sodium is described in which sodium is precipitated from the deproteinized serum by uranyl zinc acetate under conditions chosen to minimize the time required. After washing, the precipitate is taken up in water and the amount of color developed on the addition of sodium salicylate is measured.