Deionized Water Solution Research Articles

Inactivation kinetics and virulence potential of Salmonella Typhimurium and Listeria monocytogenes treated by combined high pressure and nisin.

The aim of this study was to characterize the physiological and molecular changes of Salmonella Typhimurium and Listeria monocytogenes in deionized water (DIW) and nisin solutions (100 IU/g) during high pressure processing (HPP). Strains of Salmonella Typhimurium and L. monocytogenes in DIW or nisin solutions were subjected to 200, 300, and 400 MPa for 20 min. The Weibull model adequately described the HPP inactivation of Salmonella Typhimurium and L. monocytogenes. Salmonella Typhimurium and L. monocytogenes populations were reduced to less than 1 CFU/ml in DIW and nisin solutions under 400 MPa. The highest b value was 5.75 for Salmonella Typhimurium in nisin solution under 400 MPa. L. monocytogenes was more sensitive to pressure change when suspended in DIW than when suspended in nisin. The pressure sensitivity of both Salmonella Typhimurium and L. monocytogenes was higher in DIW solution (141 to 243 MPa) than in nisin solution (608 to 872 MPa). No recovery of HPP-injured cells in DIW and nisin solutions treated at 400 MPa was observed after 7 days of refrigerated storage. The heterogeneity of HPP-treated cells was revealed in flow cytometry dot plots. The transcripts of stn, invA, prfA, and inlA were relatively down-regulated in HPP-treated nisin solution. The combination of high pressure and nisin could noticeably suppress the expression of virulence-associated genes. These results provide useful information for understanding the physiological and molecular characteristics of foodborne pathogens under high-pressure stress.

Synthesis and luminescence properties of YVO4:Eu3+ cobblestone - like microcrystalline phosphors obtained from the mixed solvent - thermal method

Abstract The mixed solvent-thermal method has been developed for the synthesis of YVO 4 :Eu 3+ luminescent materials in the N, N-dimethylformamide (DMF)/ de-ionized water (DIW) solution. The samples have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electronic microscope (TEM), UV/vis absorption and photoluminescence spectroscopies. The results demonstrate that we have obtained the uniform YVO 4 :Eu 3+ cobblestone - like microcrystalline phosphors in the mixed solution of DMF and DIW, which are different to the as-obtained YVO 4 :Eu 3+ nanoparticles in pure DIW. And the as - prepared YVO 4 :Eu 3+ microcrystalline particles are composed of numerous nanoparticles. The assembling phenomenon of the nanoparticles is strongly affected by the pH value of the solution and the volume ratio of DMF/DIW. Under UV excitation, the samples can emit the bright red light. While, the photoluminescence (PL) intensities of YVO 4 :Eu 3+ show some difference for samples obtained under the different reaction conditions. This is because that different microstructures of samples result in different combinative abilities between the surface and the adsorbed species so as to produce the different quenching abilities to the emission from Eu 3+ ions.

Desorption of cesium from granite under various aqueous conditions

In this work the desorption of cesium ions from crushed granite in synthetic groundwater (GW) and seawater (SW) was investigated. Results were compared with those obtained in deionized water (DW) and in two kinds of extraction solutions, namely: MgCl(2) and NaOAc (sodium acetate). In general, the desorption rate of Cs from crushed granite increased proportionally with initial Cs loadings. Also, amounts of desorbed Cs ions followed the tendency in the order SW>GW>NaOAc approximately equal MgCl(2)>DW solutions. This indicated that the utilization of extraction reagents for ion exchange will underestimate the Cs desorption behavior. Fitting these experimental data by Langmuir model showed that these extraction reagents have reduced Cs uptake by more than 90%, while only less than 1% of adsorbed Cs ions are still observed in GW and SW solutions in comparison to those in DW. Further SEM/EDS mapping studies clearly demonstrate that these remaining adsorbed Cs ions are at the fracture areas of biotite.

Synthesis and Characterization of CdSe Microspheres via Solvothermal Process

CdSe particles with the wurtzite structure have been synthesized via solvothermal method using a mixed solution of triethylenetetramine (TETA) and de-ionized water (DIW) without adding a reducing agent. It was found that the ball-like CdSe precursor with the zinc-blende phase could be transformed to the wurtzite structure after heat-treating at 580 °C in Ar atmosphere and the obtained microspheres were composed of small CdSe particles. The experimental results were compared with that obtained without TETA and it was speculated that TETA in the mixed solution played a role of reducing agent and solvent. Both the as-prepared products and the annealed powders were systematically characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared absorbance spectroscopy (FTIR).

Effect of Membrane Structural Characteristics on Mass Transfer in a Membrane Absorption Process

Carbon dioxide is absorbed by de-ionized water or NaOH aqueous solution in the unsteady-state membrane absorption process. A theoretical model has been developed to describe the mass transfer behavior in the liquid phase, in which the effects of membrane structural characteristics are investigated. The concentration profiles in the liquid phase are calculated as a function of time. When the membrane porosity is relatively high or the pore size is relatively small, the solute concentration profile near the membrane surface can get homogeneous instantly due to the short distance between adjacent pores. In this case, the existence of the porous membrane has less effect on the mass transfer process. However, when the membrane porosity is relatively low or the pore size is relatively large, the distance between the adjacent pores is large, so the concentration profile near the membrane surface is hard to get homogeneous during the absorption process. Therefore, the concentration profile can be influenced significantly by the membrane structural characteristics, which means that the membrane structure has a significant effect on the mass transfer in liquid phase. Moreover, the chemical reaction in the liquid phase makes it difficult for the concentration profile near the membrane surface to get homogeneous. The disturbance in the liquid phase caused by the gas flow and pressure fluctuation is also taken into account in the model, and the model results agree well with the experimental data.

An in vitro investigation of the mechanical–chemical and biological properties of calcium phosphate/calcium silicate/bismutite cement for dental pulp capping

The properties of new calcium phosphate/calcium silicate/bismutite (CPCSBi) cement were compared with those of calcium hydroxide (CH) and Dycal cements in dental pulp-capping applications. CPCSBi is composed of hydroxyapatite, tetracalcium phosphate, bismutite, and calcium silicate, which was analyzed by SEM, FTIR, and XRD. The results of ion release from CPCSBi showed that the concentrations of Bi(3+), Ca(2+), PO4(2-), and Si(4+) increased with time in deionized water solutions. The setting time of CPCSBi and Dycal was 13 min 50 s and 2 min 25 s, respectively. There were no statistical differences in compressive strength and solubility between CPCSBi and Dycal (p > 0.05). The pH of CPCSBi (10.9) was lower than that of CH (11.6) and Dycal (12.5) after immersion for 24 h. Only slight cytotoxicity appeared for CPCSBi, whereas both CH and Dycal produced moderate discoloration and lysis. In antimicrobial tests against Sm, Av, La, and Sa, the antimicrobial potency of the CPCSBi was approximately 5-10 times greater than that of Dycal and CH groups. The dissoluble dentin matrix components (DDMCs) extracted from CPCSBi exposed to dentin powder demonstrated increased expression of dentin sialophosphoprotein (DSPP) and soteocalcin (OCN) dramatically in human pulp cells by RT-PCR. These results suggest that CPCSBi will be a good candidate for use as a dental pulp-capping agent in future.

Simulations of solute concentration profile and mass transfer behavior near the membrane surface with finite volume method

Membrane gas absorption technique is one of the most attractive alternatives for CO2 capture. In this paper, a mathematical model for membrane gas absorption process has been developed to describe the solute concentration profile and the mass transfer behavior near the membrane surface, which are important factors for the process. The finite volume method is used to solve the model. The modeling results show that the different solute diffusing distances in the vertical and parallel directions near the membrane surface result in varied concentration profiles. For the membrane with small pore size, the solute concentration profile near the membrane surface can reach uniform distribution instantly, and the membrane porosity has little effect on mass transfer. Contrarily, for the membrane with large pore size, especially at higher absorbent pH value or liquid velocity, the solute concentration distribution is comparatively non-uniform. The mass transfer is significantly affected by membrane porosity. That is the mass transfer coefficients are varied at different membrane porosities. Experiments are conducted to verify the model for CO2 removal using flat sheet membrane contactor with de-ionized water or NaOH solution as absorbents. The comparison between the experimental results and the prediction results shows that the model is validated.

Synthesis of CdSe microspheres via solvothermal process in a mixed solution

CdSe particles with wurtzite structure have been synthesized via solvothermal method using a mixed solution of triethylenetetramine (TETA) and de-ionized water (DIW). It was found that ball-like CdSe precursor with zinc-blende phase could be transformed to wurtzite structure after heat-treating at 580 °C in Ar atmosphere and the obtained microspheres were made up of many nanometer sized CdSe particles. The experimental results were compared with CdSe obtained via hydrothermal method using N 2H 4·H 2O as the reducing agent and it was found that CdSe nanorods with wurtzite structure were obtained. It was speculated that TETA in the mixed solution played the role of reducing agent and surfactant. Both the as-prepared products and the annealed powders were systematically characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared absorbance spectroscopy (FTIR) and thermogravimetric analysis (TGA).

Viscous flow and colloid transport near air–water interface in a microchannel

In order to understand the transport behavior of colloids near an air–water interface (AWI), two computational methods are applied to simulate the local water flow field near a moving AWI in a 2D microfluidic channel. The first method is a mesoscopic multicomponent and multiphase lattice Boltzmann (LBM) model and the second is the macroscopic, Navier–Stokes based, volume-of-fluid interface tracking method. In the LBM, it is possible to predict the dynamic contact angles after the static contact angle is correctly set, and the predicted dynamic contact angles are in good agreement with previous observations. It is demonstrated that the two methods can yield a similar flow velocity field if they are applied properly. The flow field relative to AWI depends on the direction of the flow, and exhibits curved streamlines that transport fluid between the center of the channel and the wall region. Using the obtained flow, the motion of sub-micron colloids in a de-ionized water solution is then studied by a Lagrangian approach. The observed colloid trajectories are in qualitative agreement with our visualizations using a confocal microscope.

Pulsed-Laser-Induced Simple Synthetic Route for Tb3Al5O12:Ce3+Colloidal Nanocrystals and Their Luminescent Properties

Cerium-doped Tb3Al5O12(TAG:Ce3+) colloidal nanocrystals were synthesized by pulsed laser ablation (PLA) in de-ionized water and lauryl dimethylaminoacetic acid betain (LDA) aqueous solution for luminescent bio-labeling application. The influence of LDA molecules on the crystallinity, crystal morphology, crystallite size, and luminescent properties of the prepared TAG:Ce3+colloidal nanocrystals was investigated in detail. When the LDA solution was used, smaller average crystallite size, narrower size distribution, and enhanced luminescence were observed. These characteristics were explained by the effective role of occupying the oxygen defects on the surface of TAG:Ce3+colloidal nanocrystal because the amphoteric LDA molecules were attached by positively charged TAG:Ce3+colloidal nanocrystals. The blue-shifted phenomena found in luminescent spectra of the TAG:Ce3+colloidal nanocrystals could not be explained by previous crystal field theory. We discuss the 5d energy level of Ce3+with decreased crystal size with a phenomenological model that explains the relationship between bond distance with 5d energy level of Ce3+based on the concept of crystal field theory modified by covalency contribution.

The bioactivity of rhBMP-2 immobilized poly(lactide-co-glycolide) scaffolds

In this study, immobilization of rhBMP-2 on polylactone-type polymer scaffolds via plasma treatment was investigated. To introduce proper functional groups on the surface of poly(lactide-co-glycolide) (PLGA) matrix, PLGA films were treated under different atmospheres, such as oxygen, ammonia and carbon dioxide, respectively, and then incubated in rhBMP-2 solution of de-ionized water. The effect of various plasma-treated PLGA films on binding rhBMP-2 was investigated and compared. It was found that PLGA binding ability to rhBMP-2 was enhanced by carbon dioxide and oxygen plasma treatment, and the binding ability of the oxygen plasma-treated PLGA (OT-PLGA) to rhBMP-2 was the strongest after oxygen plasma treating for 10 min under a power of 50 W. The changes of surface chemistry and surface topography of PLGA matrix induced by oxygen plasma treatment played main roles in improving the PLGA binding ability to rhBMP-2. The stability of rhBMP-2 bound on OT-PLGA film was determined under a dynamic condition by a Parallel Plate Flow Chamber. The result showed that the rhBMP-2 had been immobilized on the OT-PLGA film. Mouse OCT-1 osteoblast-like cell as a model cell was cultured on the rhBMP-2 bound OT-PLGA (OT-PLGA/BMP) in vitro, which showed that the bound rhBMP-2 via oxygen plasma treatment was bioactive. Depending on hydrophilicity and rich polar O-containing groups of the OT-PLGA scaffold, different amount of rhBMP-2 could be evenly immobilized on the surface of the OT-PLGA scaffold. The immobilized rhBMP-2 had stimulated differentiation of OCT-1 cell and accelerated process of mineralization of OCT-1 cell in the scaffold. It revealed the rhBMP-2 immobilized PLGA scaffold had good cell affinity.

Aqueous ozone can extend vase-life in cut rose

SummaryIn order to quantify the shelf-life response of cut roses when stored in aqueous ozone solutions, cut ‘Pascha’ roses were stored in either de-ionised water or aqueous ozone solutions containing an initial dissolved ozone residual of 5.5 mg l−1. The results showed that storing cut roses in aqueous ozone solutions (5.5 mg l−1; renewed daily) can extend vase-life approx. three-fold, from 5 d to 13 d, with a corresponding improvement in their aesthetic appearance throughout the vase-life of the cut rose stem. Results suggest that vase-life improvements are achieved through a reduction in bacterial populations present in the storage solution. Bacteria accumulate on the cut surface of the stems, thereby reducing their water uptake capacity. Microbial accumulation was reduced by 1.15 log10 CFU g−1 FW when stems were stored in holding solutions containing 5.5 mg l−1 dissolved ozone, with a corresponding increase in water uptake. Roses stored in ozonated water exhibited higher numbers of functional xylem vessels, water uptake, relative water content, relative fresh weight, acid fuchsin uptake rate, leaf stomatal conductance, and net CO2 assimilation rate, compared to those stored in de-ionised water. The results suggest that ozone can extend cut rose vase-life.

Controlled synthesis and characterization of ZnSe nanostructures via a solvothermal approach in a mixed solution

In the present study, ZnSe nanostructures with complex morphologies and different phase structures were synthesized via a solvothermal approach using a mixed solution of triethylenetetramine (TETA) and de-ionized water (DIW). It was found that the phase and morphology of the as-prepared products could be controlled by changing the volume ratio of TETA to DIW. Metastable ZnSe nanoflowers with layered structure could be obtained from pure TETA, which can be transformed to the wurtzite structure after heat-treating at 500 °C in Ar atmosphere. With the addition of DIW, the morphology changed from flowers to spheres, and when the volume ratio of TETA to DIW was 1:1, loose spheres composed of nanoparticles were obtained. Variation of the TETA content in the mixed solvent also allows controlling of the crystallographic phase of ZnSe (wurtzite or zinc blende). Both the as-prepared products and the annealed powders were systematically characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared absorbance spectroscopy (FTIR), thermogravimetric analysis (TGA), and ultraviolet–visible (UV–vis) spectroscopy methods.

Development and characterization of a blood mimicking fluid for high intensity focused ultrasound

A blood mimicking fluid (BMF) has been developed for the acoustic and thermal characterizations of high intensity focused ultrasound (HIFU) ablation devices. The BMF is based on a degassed and de-ionized water solution dispersed with low density polyethylene microspheres, nylon particles, gellan gum, and glycerol. A broad range of physical parameters, including attenuation coefficient, speed of sound, viscosity, thermal conductivity, and diffusivity, were characterized as a function of temperature (20-70 degrees C). The nonlinear parameter B/A and backscatter coefficient were also measured at room temperature. Importantly, the attenuation coefficient is linearly proportional to the frequency (2-8 MHz) with a slope of about 0.2 dB cm(-1) MHz(-1) in the 20-70 degrees C range as in the case of human blood. Furthermore, sound speed and bloodlike backscattering indicate the usefulness of the BMF for ultrasound flow imaging and ultrasound-guided HIFU applications. Most of the other temperature-dependent physical parameters are also close to the reported values in human blood. These properties make it a unique HIFU research tool for developing standardized exposimetry techniques, validating numerical models, and determining the safety and efficacy of HIFU ablation devices.

Control and Implementation of a Real-Time Liquid Spotting System for Microarray Applications

This paper discusses the control and implementation of a real-time spotting system. It is intended for high-density high- yield microarray fabrication to facilitate diagnostic and research effort in genomics and proteomics. The method is based on a self-sensing fully automated aspiring/dispensing pin. System performance is evaluated by several batch runs with deionized water solutions of 0.3% fluorescent Cy-3 dye, which has similar physical properties to the deoxyribonucleic acid (DNA) probe materials. Experimental results show that this system is capable of fast and robust DNA/protein microarray fabrication in high volume while keeping spot size as small as 60 mum consistently. Based on the laser scanned images and experimental data of the spotted microarrays, it is also verified that this system can recognize and prevent the formation of abnormal spots.

Saline soak tests to determine the short-term reliability of an in situ thin film resistance temperature detector

With an objective to assess the short-term reliability of thin film, encapsulated resistance temperature detectors (RTDs) in corrosive environments, these were placed in aqueous soak solutions of double de-ionized water (DDI) and phosphate buffered solution (PBS) or saline for eight weeks. They were removed weekly in order to characterize the effects of the solutions on their electrical properties, as well as their thermal response. The solutions were analyzed weekly as well with an FT-IR spectrometer in order to determine if chemical reactions took place during the soak tests and optical micrographic studies were carried out too. The RTDs appeared not to suffer degradation during the period of study. Nonetheless, it turned out that the soak tests offer a user-friendly and safe approach to remove the Benzocyclobutene (BCB) layer; this is an issue that is likely to be of some interest in the electronics fabrication community.

Synthesis of Mg(OH) 2, MgO, and Mg nanoparticles using laser ablation of magnesium in water and solvents

Laser ablation of magnesium in deionized water (DW), solutions of DW and sodium dodecyl sulfate (SDS) with different concentrations, acetone and 2-propanol has been conducted. The results showed that ablation in acetone and 2-propanol yielded MgO and Mg nanocrystallites as isolated particles and agglomerated chains probably intermixed with organic residues resulting from the alteration/decomposition of the solvents under the high-energy conditions. Brucite-like Mg(OH) 2 particles were mainly produced by laser ablation of Mg in either DW or DW–SDS solutions. Ablation in DW yielded particles of fiber-like shapes having a diameter of about 5–10 nm and length as long as 150 nm. Materials produced in DW–SDS solutions were composed of various size and shape particles. Some had rough surfaces with irregular shapes. Small particles were about 20–30 nm and larger particles were about 120 nm. Particles with rod-like, triangular, and plate-like shapes were also observed.

The effect of the ionic strength on the rheological behavior of hydrophobically modified polyacrylamide aqueous solutions mixed with sodium dodecyl sulfate (SDS) or cetyltrimethylammonium p-toluenesulfonate (CTAT)

Two hydrophobically modified polyacrylamides (HMPAMs) with different molar contents of t-octylacrylamide as hydrophobic comonomer (1 and 1.5%molar) were synthesized by aqueous micellar copolymerization in water. The molecular structure was characterized in detail by light scattering and viscometric measurements using automatic continuous mixing (ACM) techniques in dilute solution. There was no significant difference between the weight average molecular weight (Mw) of homopolyacrylamide and the copolymers. The elucidation of polymer microstructure by 1H NMR showed that the hydrophobe content in the polymer backbone is almost the same as the hydrophobe content in the feed. This study reveals that branched t-octyl alkyl chains are not hydrophobic enough to induce significant associating properties, but can exhibit strongly magnified thickening properties in the presence of surfactant. The effect of NaCl addition to the solutions of the prepared HMPAMs was also explored as well as their interactions with sodium dodecyl sulfate (SDS) or cetyltrimethylammonium p-toluenesulfonate (CTAT). A direct comparison of the influence of spherical surfactant micelles and worm-like micelles on the rheological properties of the same polymer samples was made. For a given HMPAM copolymer at a fixed concentration in deionized water, the solutions zero-shear viscosities tend to increase upon adding surfactant, then they go through a maximum and then decrease (in the case of CTAT the viscosity after the maximum tends to slowly increase with CTAT concentration). These well known effects are due to the hydrophobic interactions between HMPAM and SDS or CTAT. The maximum viscosity occurs in HMPAM/SDS deionized water solutions. However, we demonstrate that by the addition of salt, the HMPAM/CTAT solutions can exhibit much higher viscosities (two orders of magnitude) than HMPAM/SDS solutions at low CTAT concentrations and high ionic strengths (larger than 1.5M NaCl). This pronounced increased in viscosity is attributed to the growth of the CTAT worm-like micelles as the ionic strength increases, which can interact with the hydrophobic groups present in the HMPAMs and can form an entangled interacting network in solution.

Cytotoxicity of Aggregated Fullerene C60 Particles on CHO and MDCK Cells

The cytotoxicity of fullerene C60 particles on two mammalian cell lines, i.e. the Chinese hamster ovary (CHO) cells and the Madin-Darby canine kidney (MDCK) cells, has been investigated. Although innate fullerene particles have a very low solubility in deionized (DI) water, these particles can be dissolved in the tetrahydrofuran (THF) solvent at a great value. Further, the dissolved fullerene particles in the THF solvent could be extracted into a DI water solution at a significantly increased solubility. The formation of fullerene particle aggregates is believed to be the cause of the increased solubility. Results presented here show that once the concentration of the fullerene aggregates reaches a certain level, the cells start to die. The lethal dosage LD50, which is defined as the lowest fullerene concentration that results in a 50% cell death within 24 h, has been determined. Furthermore, the percentage of cell mortality increased with increasing fullerene concentration and incubation time yielding a negative effect on cell viability. These results, illustrated by atomic force microscopy (AFM), dynamic light scattering (DLS) and other microscopic techniques, will help to better understand the side effects of fullerene particles in mammalian cells.

Pristine narrow-bandgap Sb 2S 3 as a high-efficiency visible-light responsive photocatalyst

Pristine Sb2S3, prepared by solid state reaction, was found to have an optical absorption edge of about 800 nm and a band gap of about 1.55 eV. Its photocatalytic activity was investigated by degrading methyl orange directly in the deionized water solution under visible light. Sb2S3 performed much better than P25, Bi2S3 and CdS under the same condition. The high-efficiency of Sb2S3 is due to the broad spectrum response and the suitable valence band position.