Total Amount Of Solute Research Articles

Comparison of the effects of articaine and bupivacaine in impacted mandibular third molar tooth surgery: a randomized, controlled trial.

BackgroundThe aim of this randomized, triple-blind trial was to determine the anesthetic, analgesic, and hemodynamic effects of articaine and bupivacaine in the extraction of impacted mandibular third molar teeth.MethodsTwenty-six patients who underwent removal of bilaterally symmetric mandibular third molars were randomly assigned to articaine and bupivacaine groups in a split-mouth design. The onset of anesthetic action, intraoperative comfort, total amount of solution used, duration of postoperative anesthesia and analgesia, rescue analgesic use, postoperative pain, intraoperative bleeding, and hemodynamic parameters were evaluated.ResultsIn the articaine group, the onset of anesthetic activity was faster, intraoperative comfort was greater, and effective anesthesia required less local anesthetic solution. The bupivacaine group showed a significantly longer duration of postoperative anesthesia and analgesia, in addition to lower visual analog scale values at 6 and 48 hours postoperatively. There were no significant differences between the two solutions regarding rescue analgesic medication use, intraoperative bleeding, or hemodynamics.ConclusionArticaine showed greater clinical efficacy than bupivacaine in intraoperative anesthesia, achieving faster onset of anesthetic action and greater patient comfort while also requiring less reinforcement during surgery. However, bupivacaine was superior in terms of postoperative anesthesia, reducing postoperative pain due to its residual anesthetic and analgesic effects. Both anesthetic solutions led to similar hemodynamics at low doses in mandibular third molar surgery.

The effect of cannabis dry flower irradiation on the level of cannabinoids, terpenes and anti-cancer properties of the extracts

Abstract Flowers of Cannabis sativa contain many potentially therapeutic ingredients, including phytocannabinoids and terpenes. Consumption of cannabis requires drying and processing flowers which can potentially lead to accumulation of pathogens, including fungi and bacteria. In many countries, the level of pathogens in dried flowers is strictly regulated and thus, licensed cannabis cultivators irradiate dry flowers to decrease the chance of accumulation of pathogens. We have hypothesized that irradiation of flowers may change the level of active ingredients in flowers. We have tested the effect of gamma-radiation on the level of cannabinoids and terpenes in four varieties of cannabis. Plants were grown to maturity and flowers were harvested. One flower sample per variety was irradiated with 5 kGy using electron beam, while another sample was mock-treated. Cannabinoids were analyzed using HPLC and terpenes using GC-FID. Ethyl acetate was used to prepare extracts from two sets of flowers and extracts were tested for anti-proliferative capacity using methyl-thiazolyl-tetrazolium (MTT) assay on four different cancer cell lines, BJ-5ta, BT16, HCC1806 and IMR5. Solvent-based extraction of irradiated flowers showed slight increase in the total amount of solute. Irradiation of flowers resulted in the increased level of cannabinoids in the extract, more prominent in delta-9-tetrahydrocannabinol. There was also an increase in terpenes content in some cultivars. MTT assay showed that irradiation of flowers changed anti-cancer properties of three out of four tested extracts. Our experiments demonstrated that irradiation of flowers changes the amount of active ingredients in the extract and anti-cancer properties of such extracts.

Excess partial molar entropy of alkane-mono-ols in aqueous solutions at 25°C

In the preceding paper, we reported the values of model-free chemical potentials for aqueous methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and 1-hexanol at 25°C over the entire compositional region. Using alcohol excess partial molar enthalpies, HEAL, determined earlier in this laboratory (Can. J. Chem. 74, 713 (1996)), we have calculated excess partial molar entropies for the alcohols, SEAL, where AL stands for an alcohol. We then calculated, numerically, the entropic interaction, SEAL–AL = N([Formula: see text]SEAL/[Formula: see text]nAL)p,T,nW, where nAL is the amount of AL, nW is the amount of H2O, and N is the total amount of solution. SEAL–AL signifies the effect of addition of AL upon the entropic situation of existing AL in solution. Using these quantities, the mixing schemes in aqueous alcohols have been studied. The earlier conclusions, which used HEAL and HEAL–AL alone, are confirmed. Furthermore, the order of the relative hydrophobic nature of alcohols is established from the behaviour of SEAL–AL and of HEAL–AL as methanol < ethanol < 2-propanol < 1-propanol. Key Words: aqueous alcohols, excess partial molar entropies, entropic interaction mixing schemes, hydrophobicity ranking.

Analytical Modeling of Nonaqueous Phase Liquid Dissolution with Green's Functions

Equilibrium and bicontinuum nonequilibrium formulations of the advection–dispersion equation (ADE) have been widely used to describe subsurface solute transport. The Green's Function Method (GFM) is particularly attractive to solve the ADE because of its flexibility to deal with arbitrary initial and boundary conditions, and its relative simplicity to formulate solutions for multi‐dimensional problems. The Green's functions that are presented can be used for a wide range of problems involving equilibrium and nonequilibrium transport in semi‐infinite and infinite media. The GFM is applied to analytically model multi‐dimensional transport from persistent solute sources typical of nonaqueous phase liquids (NAPLs). Specific solutions are derived for transport from a rectangular source (parallel to the flow direction) of persistent contamination using first‐, second‐, or third‐type boundary or source input conditions. Away from the source, the first‐ and third‐type condition cannot be expected to represent the exact surface condition. The second‐type condition has the disadvantage that the diffusive flux from the source needs to be specified a priori. Near the source, the third‐type condition appears most suitable to model NAPL dissolution into the medium. The solute flux from the pool, and hence the concentration in the medium, depends strongly on the mass transfer coefficient. For all conditions, the concentration profiles indicate that nonequilibrium conditions tend to reduce the maximum solute concentration and the total amount of solute that enters the porous medium from the source. On the other hand, during nonequilibrium transport the solute may spread over a larger area of the medium compared to equilibrium transport.

Comparison of quantitative analytical methods in headspace gas chroamtography of residual solvents

The aim of this work was to compare quantitative methods used for headspace gas chromatographic analysis of residual solvents in standard aqueous solutions and to apply the methods to the analysis of medicines. We found that all three quantitative methods (external standard, ESTD; internal standard, ISTD; and standard addition, ASTD) enable determination of the total amount of solute in the equilibrated system by analysis of defined volumes of headspace gas. The results showed that the ISTD method is more precise than ESTD and ASTD when there is no strong interaction between the residual solvents and the pharmaceutical base material. When, however, there is a strong polarpolar interaction between them, the ESTD and ISTD methods give worse results than the ASTD method, because the ASTD method can eliminate the matrix effect.

Spatial and temporal variations in San Joaquin Valley fog chemistry

Fog was sampled at four locations in California’s San Joaquin Valley (SJV) during December 1995 and January 1996 as part of the 1995 Integrated Monitoring Study (IMS95). The fog sampling campaign was conducted in two phases. During the first phase, fog was sampled at three southern SJV surface locations, two urban (Fresno and Bakersfield) and one rural (near the Kern Wildlife Refuge). Both bulk samples (representative of the entire fog drop spectrum) and size-fractionated samples were collected. During the second phase, bulk fog samples were collected at three elevations on a 430 m television transmission tower in the northern SJV, representing some of the first observations of vertical variations in fog composition. SJV fog was observed to be consistently alkaline. The median pH measured in the southern SJV was 6.49, with a range from 4.97 to 7.43. Dominant species in the fog water were ammonium (median southern SJV concentration of 1008 microequivalents/l (μN)), nitrate (483 μN), sulfate (117 μN), acetate (117 μN), formate (63 μN), and formaldehyde (46 μM). Concentrations of the inorganic ions were similar in the urban and rural fogs, although occasionally much higher spikes of S(IV) and sulfate were observed in Bakersfield fog. Acetate, formaldehyde, and total organic carbon, by contrast, were observed to be present in greater concentration in the urban fogs. Bakersfield IMS95 fog concentrations of most species were similar to those measured there in the early 1980s, although concentrations of S(IV) and sulfate were much lower in IMS95 fogs. Significant differences were found between the composition of large and small fog drops, with pH differences at times exceeding one pH unit. The chemical heterogeneity present among SJV fog drop populations is likely to result in significant enhancement of aqueous sulfate production rates over those expected from average fog properties. Significant vertical variations were also observed in fog composition. Liquid water content was observed to increase strongly with elevation, while major ion aqueous concentrations in fog drops decreased with altitude. The total amount of solute contained within the fog (per unit volume of air) was observed to increase with altitude. These observations form a unique data set to be used for model evaluation and for further analysis of aerosol processing by fogs.

Fos induction in rat brain neurons after stimulation of the hepatoportal Na-sensitive mechanism.

Responses of hepatic afferent nerves to intraportal bolus injection of hypertonic solutions were examined in anesthetized rats. Hepatic afferent nerve activity increased in response to an intraportal injection of 0.75 M NaCl or NaHCO3 but did not respond to a similar injection of 1.5 M mannitol, 0.75 M LiCl, or 0.15 M NaCl, implying that nerves in the hepatoportal area are sensitive to increases in Na concentrations and that this leads to stimulation of hepatic afferent nerve activity. To study central activation in response to stimulation of the hepatic Na-sensitive mechanism, c-fos induction was monitored. After electrical stimulation of hepatic afferent nerves, neurons containing Fos-like immunoreactivity (Fos-li) were found in the area postrema, nucleus of the solitary tract, paraventricular hypothalamic nucleus, and supraoptic nucleus at 90 min after stimulation. Induction of Fos-li was also studied after simultaneous infusion of 0.45 M NaCl into the portal vein and distilled water into the inferior vena cava in conscious rats so as to keep the total amount of solution introduced into the systemic circulation isotonic, thus avoiding changes in mean arterial pressure, plasma osmolality, and plasma NaCl concentrations. Fos-li-containing neurons were found in the same regions in which they were found after electrical stimulation. However, few, if any, Fos-li-containing cells were found if the rats were hepatically denervated or if they received an intraportal infusion of hypertonic LiCl or mannitol. These data provide evidence for involvement of the brain stem and forebrain structures in NaCl regulatory functions induced by stimulation of the hepatoportal Na-sensitive mechanism. However, stimulation of the hepatoportal osmosensitive mechanism does not activate these central structures.

The influence of microencapsulation using Eudragitr` RS100 on the hydrolysis kinetics of acetylsalicylic acid

Homogeneous Eudragit® RS100 matrix microspheres containing molecularly dispersed acetylsalicylic acid (ASA) were prepared in order to investigate the effect of encapsulation on the decomposition rate of a hydrolytically susceptible drug. ASA-loaded microspheres of this non-eroding polymer matrix were analysed at predetermined time points following immersion of the microspheres in temperature controlled buffer systems at pH 1.2 or pH 12.1 at 30, 40 or 50°C. The mass balance of the total amount of solutes (ASA and SA) initially located within the microsphere interior was equal to the sum of the amount of solutes remaining in the microsphere interior and the amount of solutes in the aqueous phase at any time during the course of the study. Each analysis involved the quantitation of four species; the drug and decomposition product, salicylic acid (SA), in both the microsphere phase and the external aqueous phase. A simple model system using first-order rate approximations for the concurrent Fickian diffusion and hydrolysis decomposition of the drug resulted in a multi-exponential expression which adequately described the time-course profile of the drug. SA-loaded microspheres were used as a control under similar conditions to determine the magnitude of the contribution of microsphere phase hydrolysis of ASA to the overall rate of drug loss from the microspheres. Results indicated that microsphere phase hydrolysis of ASA was minimal. Even after 900 h of immersion in pH 12.1 buffer some ASA remained within the micro-sphere. It is postulated that the matrix incorporated drug is essentially shielded from hydrolytic attack until it is liberated into the external aqueous environment. Electrostatic association of the drug with the charged quaternary residues in the polymer along with the limiting availability of water within the micro-sphere may be responsible for the observed stability of ASA in aqueous swollen ASA-loaded Eudragit® microspheres.

Second-order recombination in a parallel shear flow

For a reactive solute, with weak second-order recombination, an investigation is made of the near-source behaviour (where concentrations are high), and of the far field (where the recombination has an accumulative effect). Despite the loss of material and increased spread due to recombination, the far-field concentration distribution is shown to be nearly Gaussian. This permits a simplified (Gaussian) treatment of the chemical nonlinearity. Explicit solutions are given for the total amount of solute, variance and kurtosis for solutes with no first-order reactions.

The effects of finite melt volume on proton exchanged lithium niobate

The effects of using a benzoic acid melt of limited volume on proton-exchanged LiNbO/sub 3/ crystals are discussed. It was found, by observing the strength of the O-H peak as a function of exchange time, that the amount of hydrogen entering the crystal saturates if the benzoic acid melt is of limited volume. This behavior has been modeled using the condition that the concentration of free protons in the melt decreases as the exchange proceeds. A good fit of the data based on this model can be obtained by considering the total amount of solute in the system to a constant. Diffusion coefficients deduced from the model agree well with the ones reported in the literature.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Sputtering chromatography of some inorganic cations

A new device for the column chromatography has been proposed. The sample solution (0.5 ml) containing each 0.1 mg of the cations, is placed in a bulblike vessel (3ml) connected with a glass tube holding a chromatographic column of cellulose powder impregnated with chelating agents.The top and bottom of the column are fixed with glass wool, and the vessel is immersed in hot water. The top of tube is connected with vacuum line (20 mm Hg).The solution is consequently boiled vigorously with repeated eruption. The total amount of solution is transferred to the column in 10 minutes and, meantime, the development is carried out giving a consistent chromatogram. The method is applied to quarternary (Hg2+, Co2+, Cu2+ and Fe3+) and tertiary (Fe2+, Cu+ and Co2+) systems using oxine and phenyl-2-pyridyl-ketoxime, respectively, as coloring agents. An advantage of the method is that the chromatography of readily oxidizable cations is accomplished by applying suitable degree of vacuum for avoiding air-oxidation. The method may be applied also for organic substances. The term sputtering chromatography is suggested.

REFRACTIVE INDICES, SPECIFIC GRAVITIES, AND SOLUTION FACTORS OF SOLUTIONS OF THE SOLIDS OF WORT, COLD-WATER EXTRACT AND BEER

For such solutions of mixed solutes as worts and beers, only an approximate general relationship can be established between either the refractive index or the specific gravity of the solution and the total amount of solute; consequently, arbitrary factors or tabulated figures based on pure solutes are in common use. Freeze-drying offered a means of preparing the solids from typical worts and beers in a dry and unaltered form, and, by using these solids, of establishing directly in a limited number of cases the relationships between physical characters and concentrations of solutions. From the consolidated results solution factors have been calculated, and the concentrations which they indicate for the materials now examined have been compared with those obtained from the Plato Table and the Zeiss Immersion Re-fractometer Table for sucrose. It is shown that the use of these tables leads in the present cases, and probably more generally, to overestimation of the amounts of substance in solution. Similarly, the solution factor 3·86, used in the Institute of Brewing standard method for the determination of cold-water extract, has given high results, and more accurate figures, over the range of gravities encountered for this determination in average malts, were obtained from the factor 3·93. Methods are described for determining temperature corrections for the specific gravities of laboratory worts, cold-water extract filtrates, and solutions of beer solids.