Capillary Viscometer Research Articles

The Effect of Ezetimibe on Plasma Viscosity, Fibrinogen and Lipid Profile

Objectives: The aim of this study is to reveal the effect of ezetimibe monotherapy on plasma viscosity and fibrinogen levels in hyperlipidemia. Material and Methods: A study group of 31 hyperlipidemic patients was treated for twelve weeks with a monotherapy of ezetimibe 10 mg/day. A healthy control group of 31 individuals with normal plasma lipid profile was also admitted to the study. PV, fibrinogen and fasting lipid parameters were evaluated. PV was measured by Harkness Capillary Viscometer. Results: PV and fibrinogen levels decreased significantly with ezetimibe monotherapy (p<0.01). Total cholesterol and low density lipoprotein (LDL) levels were statistically significantly lower than ezetimibe monotherapy group (p<0.001), whereas high density lipoprotein (HDL) level was significantly higher than ezetimibe monotherapy group (p<0.01). HDL level increased significantly in ezetimibe monotherapy group (p<0.01). PV and fibrinogen levels of the control group were lower than ezetimibe monotherapy group before treatment (p<0.01 and p<0.001; respectively). Besides, fibrinogen level of control group was significantly lower than ezetimibe monotherapy group after treatment (p<0.01). Total cholesterol and LDL levels of control group was lower than ezetimibe monotherapy group before and after treatment (p<0.001 and p<0.01; p<0.001, respectively). HDL level of control group was significantly higher than ezetimibe monotherapy group before treatment (p<0.01). Conclusions: Ezetimibe monotherapy ameliorates lipid profile and PV parameters in hyperlipidemic individuals. Increased PV and deteriorations in lipid profile may induce endothelial damage in cardiovascular diseases. Being a biophysical mechanical marker, PV may be useful for diagnosis, treatment and follow-up of hyperlipidemic patients treated with ezetimibe monotherapy.

Experimental and Computational Thermodynamic Properties of (Benzyl Alcohol + Alkanols) Mixtures

Experimental data of densities, viscosities, and refractive indices of {(benzyl alcohol + methanol), ethanol, 1-propanol, 2-propanol, 1-butanol, and 2-butanol} binary mixtures were measured at T = 298.15 K and ambient pressure (81 500 Pa) using an oscillating densimeter, Ubbelohde capillary viscometer, and digital Abbe refractometer, respectively. Values of excess molar volumes, VmE, of the binary mixtures in the liquid phase at T = 298.15 K have been derived from density measurements. The experimental data are used to calculate partial molar volumes, Vi, excess partial molar volumes, ViE, excess partial molar volumes at infinite dilution, ViE,∞, deviations in the viscosity, Δη, and deviations in the refractive index, ΔnD, excess refractive index, nDE, and kinematic viscosity, ν. The calculated quantities VmE, Δη, ΔnD, and nDE have been correlated with the Redlich–Kister equation. The excess partial molar volumes, ViE,∞, and enthalpies, HiE,∞, at infinite dilution of the binary mixtures were computed by a...

Copolymerization of Acrylamide with 9‐ and 10‐Acrylamidodecanoic Acids

SummaryCopolymerization of acrylamide with 9‐ and 10‐acrylamidodecanoic acids (AADAs) has been carried out by free radical polymerization using ammonium persulphate as an initiator. AADA monomer was synthesized from 9‐decenoic acid via Ritter reaction using acrylonitrile and sulfuric acid as catalyst. Characterization of monomers and the resulting copolymers were performed by Nuclear Magnetic Resonance (NMR) and Fourier Transform‐Infrared (FT‐IR) spectroscopy, respectively. The intrinsic viscosities of copolymers with various compositions were measured using Ubbelohde capillary viscometer in 1.0 M sodium chloride solution. It was found that the intrinsic viscosity of the copolymers decreased with increasing the AADA monomer content.

Propriedades físico-químicas, apresentação de rotulagem e atividade antimicrobiana de colutórios infantis

Objective: To analyze the physicochemical properties, labeling and antimicrobial activity of mouthwashes for children against oral biofilm microorganisms. Material and Methods: We selected a total of eight brands of mouthwashes and used distilled water and chlorhexidine as negative and positive controls, respectively. The packages were analyzed by direct observation. The assessment of pH, oBrix and kinematic viscosity was carried out using a digital pHmeter, specific field refractometer and capillary viscometer, respectively. For this study, we used strains of Streptococcus oralis, Streptococcus mutans, Streptococcus salivarius and Lactobacillus acidophilus, which were reactivated in BHI and plated on blood agar. Susceptibility tests were made by the agar diffusion method, followed by incubation at 37 oC for 48 hours. Results: The pH, oBrix and viscosity values ranged from 4.89 to 7.23, 2.8 to 20.0, and 1.47 mm²/s to 2.73 mm²/s, respectively. Chlorhexidine was found to show the largest zones of inhibition against S. salivarius and L. acidophilus. This effect was observed for the mouthwashes against S. oralis and S. mutans. Conclusion: The mouthwashes for children tested herein were found to show a neutral or close to neutral pH, presence of soluble solids in their composition and little variation of viscosity. These products proved to show antimicrobial activity on the microorganisms tested, excepting one of the mouthwashes, which showed no effect on S. mutans.

Polymerization of Aniline in Microemulsion by Catalytic Air Oxidation

SummaryA copper catalyzed air oxidation process is presented for polymerization of aniline in a microemulsion constituting with cetyltrimethylammonium chloride (CTAC) and n‐butanol. The process was demonstrated to give stable and pitch‐dark emulsions of Emeraldine base in molecular weights of 33800 Da, as inferred from the capillary viscometer. A fairly linear viscosity‐conversion relation was noted in each case up to 95.0% of conversion. Differential light scattering (DLS) measurements showed 70 nm of average particle size for the polyaniline (PANI) in the emulsion. Conductivities measured by four‐ point probe technique indicated conductivities 8.3×10−8 and 9.8 Scm−1 for un‐doped and doped PANI.

Intensification of depolymerization of aqueous guar gum using hydrodynamic cavitation

Depolymerization of aqueous guar gum using hydrodynamic cavitation has been investigated for the first time, with a detailed understanding into the effect of initial concentration of polymer, inlet pressure, geometry of cavitating device, operating temperature and addition of potassium persulfate (KPS). The extent of depolymerization has been analyzed in terms of reduction in intrinsic viscosity using Ubbelohde glass capillary viscometer. It has been observed that lower initial concentration, higher inlet pressure, slit venturi as cavitating device and addition of KPS result in higher extent of depolymerization. Use of hydrodynamic cavitation alone under optimized conditions resulted in about 70% reduction in intrinsic viscosity whereas addition of KPS under optimum loading enhanced the extent of reduction to 96%. Kinetic analysis established that the kinetic rate constant increased with an increase in the temperature and concentration of KPS. FTIR analysis demonstrated that there were no structural changes and the chemical identity was retained. Hydrodynamic cavitation has been demonstrated to be more energy efficient and applicable at larger scale of operation as compared to ultrasound based operation.

Development of a simple droplet-based microfluidic capillary viscometer for low-viscosity Newtonian fluids.

Viscosity is an easily measured macroscopic property that provides molecular information and is widely used across the sciences and engineering. Here we report a microfluidic capillary viscometer that forms droplets from aqueous samples in an immiscible carrier phase and encodes information about sample viscosity in the droplet spacing. The device shows exceptional calibration stability, with only a 0.6% drift in calibration factor from run to run, the ability to handle aqueous and nonaqueous samples, and the ability to operate with sample volumes as low as 38 nL. Operating range for aqueous sample viscosity was characterized, and was found to be 0.96-52 cP. Operating range for aqueous shear rate was found to depend on aqueous viscosity and varied from 1.9 × 10(1)-4.4 × 10(2) s(-1) for high viscosity samples to 4.1 × 10(2)-6.0 × 10(3) s(-1) for low viscosity samples. Accuracy was tested by comparing measured viscosities of several samples including crème de menthe peppermint liquor, human urine, and baby oil to viscosities of the same samples obtained with a U-tube viscometer. The device was found to be very accurate, with differences between methods as low as 0.1%. The viscometer presented requires only a basic T junction and can utilize off-chip fluorescence to measure viscosity, which could allow for easy addition of viscometric measurement capabilities to existing droplet platforms. Furthermore, the device is capable of performing measurements on Newtonian fluids without precise control over pressures or flow rates, which significantly simplifies device operation.

Effects of sevoflurane and desflurane on the blood and plasma viscosity

The purpose of present study was to compare the effects of desflurane and sevoflurane on blood viscosity in three different shear rates and plasma viscosity. Forty male patients, ASAI-II, undergone tympanoplasty were included in this study. Patients were randomly categorized as anaesthetized either with sevoflurane or desflurane. Anaesthesia was maintained with inspiratory concentrations of sevoflurane 1-1.5 MAC or desflurane. The samples were taken for hemorheological and biochemical examinations before induction of anaesthesia (initial time) and at 60 th and 120 th min of the operation. Blood viscosities were measured by rotational viscometer. Plasma viscosity was measured by capillary viscometer. Patients receiving desflurane showed steady decrease at 23 1/sec shear rate at 60 th and 120 th min and in blood viscosity at 115 1/sec shear rate in 120 th min. Statistically significant decrease in the level of plasma viscosity was observed in the patient group anesthetized with desflurane, between initial time vs 60 th min (p<0.01), initial time vs 120 th min. (p<0.01). Desflurane produced stable effects on the blood circulation. The differences in the blood viscosity should not be overlooked. Keywords : Desflurane, Sevoflurane, Blood viscosity, Plasma viscosity

On the viscosity of natural gas

This study reports new experimental viscosity measurements at high pressure and high temperature for a sour natural gas mixture. The measurements were conducted with a capillary tube viscometer at pressures ranging from 10.3 to 138MPa and temperatures up to 444K. The study develops a comprehensive model to predict natural gas viscosity in a wide range of pressures, temperatures and compositions. The arithmetic average of the model’s absolute error was found to be 2.4% compared with experimental data from the literature (containing the experimental data of the current study), which is acceptable for accurate engineering calculations; the absolute error demonstrates that this model is superior to other methods.

Chemical synthesis of polypyrrole doped with dodecyl benzene sulfonic acid

Among the conducting polymers, polypyrrole (PPY) is one of the most attractive polymer due to its wide range of applications related to its good stability and conductivity. How-ever its insolubility in some common organic solvents limits its wide range of applications. In the present work an attempt has been made to synthesize soluble and stable PPY by inverse emulsion polymerization using dodecyl benzene sulfonic acid (DBSA) as a dopant as well as surfactant. A mixture of chloroform and 2-butanol was used as a novel dispersion medium and benzoyl peroxide as an oxidant. Optimizing the concentration of monomer and oxidant, the percent yield of PPY salts was calculated. Intrinsic viscosity of the PPY salts was calculated using capillary viscometer and was found to be dependent upon monomer concentration. Synthesized PPY salts were characterized by FTIR, XRD, SEM and CV. The thermal stability of the PPY-DBSA was determined by TGA in which a thermogram showing three step decomposition patterns was obtained. The synthesized PPY-DBSA was found to be stable upto 520 ºC, which is so far the highest thermal stability reported for PPY.

Effect of calcium on solution and conformational characteristics of polysaccharide from seeds of Plantago asiatica L.

Polysaccharide from seeds of Plantago asiatica L. is rich in calcium, which is important for keeping viscous and weak gelling properties of the polysaccharide. However, few studies reported effect of calcium on solution and conformational characteristics of the polysaccharide. In this study, polysaccharide was prepared from seeds of P. asiatica L. and named as PLCP. PLCP was treated with EDTA to remove calcium ion to get PLCP-E. PLCP and PLCP-E were characterized by Ubbelohde capillary viscometer, light scattering and HPSEC with refractive index, light scattering and viscometric detectors. The results showed that PLCP had much higher intrinsic viscosity, hydrodynamic radius (Rh), radius of gyration (Rg) and molecular weight than that of PLCP-E when measured in the same solvent. PLCP and PLCP-E were in random coil conformation in aqueous solutions according to light scattering and HPSEC measurements. HPSEC data showed PLCP-E had lower intrinsic viscosity than that of PLCP with the same molecular weight. Persistence length of Lp was 2.5nm for PLCP and 2.3nm for PLCP-E, respectively. In conclusion, PLCP exhibited higher intrinsic viscosity and molecular weight, and stiffer conformation than that of PLCP-E, which could explain the reason of higher viscosity of PLCP.

Comparisons between Polyvinyl Alcohol (PVOH) and Sodium Dodecyl Sulphate (SDS) as Surfactants in Natural Rubber (NR)/Polyvinyl Acetate (PVAc) Latex Blends

Solutions of sodium dodecyl sulphate (SDS) and polyvinyl alcohol (PVOH) were used respectively as surfactants in comparative viscosity measurements of pure polyvinyl acetate (PVAc) emulsion, natural rubber (NR) latex and their blends using Ostwald glass capillary viscometer. Results show the efficacy of each surfactant in bringing about thickening of the latexes which is an important step in latex stabilization after formulation. Higher thickening phenomenon was observed when SDS rather than PVOH was used in pure PVAc and the blends. Overall findings agreed with earlier literature on similar studies.

Measuring Blood Viscosity in Normal Tension Glaucoma Patients

Purpose: Non-intraocular pressure (IOP) factors such as vascular factors have been identified as contributing to normal tension glaucoma. However, there is not an established range of haemorheological factors considered normal, nor are there standardized tests. In this study, we investigated differences in blood viscosity and haemorheological parameters between patients with normal tension glaucoma (NTG) and normal controls using a new instrument called the BVD-RO1 (BIO-VISCO. Inc., Jeonju, Korea). Methods: Twenty patients with NTG and 20 age-matched normal controls were included in the study. Haemorheological parameters of the venous blood samples, including blood viscosity at the shear rates of 300 (high shear rate) and 1 (low shear rate) s−1 were measured using an automated scanning capillary tube viscometer. Results: More hematocrit concentration was detected in the NTG group than in the control group (p < 0.05). Furthermore, higher blood viscosities at the high (p < 0.01) and low (p < 0.01) shear rates were found in the NTG group. Conclusions: The NTG patients differed in blood viscosity with the control group. This may signify the importance of hemodynamic factors in the pathogenesis of NTG. J Korean Ophthalmol Soc 2015;56(5):753-758

Grounding the Human Body during Yoga Exercise with a Grounded Yoga Mat Reduces Blood Viscosity

Objective: Research continues to show that being connected to the earth can increase the potential of the body to scavenge free radicals. This study examined the effect of just one hour of grounding on blood viscosity while subjects participated in gentle yoga exercises designed to initiate minor inflammation. Design: In this double blind model, twenty-eight (28) subjects met at the Bowerman Sports Medicine Clinic on the campus of the University of Oregon and were grounded to the earth via contact with a grounded yoga mat or were sham-grounded. Ten yoga exercises were repeated five times over a one-hour period. Blood was taken pre and post exercise and analyzed for blood viscosity using a scanning capillary viscometer. Results: Subjects connected to the earth significantly reduced their post exercise systolic blood viscosity (p = 0.03) and diastolic blood viscosity (p = 0.03). Conclusion: Grounding has the ability to affect exercise induced inflammation, thereby reducing blood viscosity.

Blood thixotropy in patients with sickle cell anaemia: role of haematocrit and red blood cell rheological properties.

We compared the blood thixotropic/shear-thinning properties and the red blood cells’ (RBC) rheological properties between a group of patients with sickle cell anaemia (SS) and healthy individuals (AA). Blood thixotropy was determined by measuring blood viscosity with a capillary viscometer using a “loop” protocol: the shear rate started at 1 s−1 and increased progressively to 922 s−1 and then re-decreased to the initial shear rate. Measurements were performed at native haematocrit for the two groups and at 25% and 40% haematocrit for the AA and SS individuals, respectively. RBC deformability was determined by ektacytometry and RBC aggregation properties by laser backscatter versus time. AA at native haematocrit had higher blood thixotropic index than SS at native haematocrit and AA at 25% haematocrit. At 40% haematocrit, SS had higher blood thixotropic index than AA. While RBC deformability and aggregation were lower in SS than in AA, the strength of RBC aggregates was higher in the former population. Our results showed that 1) anaemia is the main modulator of blood thixtropy and 2) the low RBC deformability and high RBC aggregates strength cause higher blood thixotropy in SS patients than in AA individuals at 40% haematocrit, which could impact blood flow in certain vascular compartments.

Density and Viscosity of Ionic Liquid Binary Mixtures of 1-n-Butyl-3-methylimidazolium Tetrafluoroborate with Acetonitrile, N,N-Dimethylacetamide, Methanol, and N-Methyl-2-pyrrolidone

In this study, thermodynamic properties of the binary mixtures of ionic liquid with an organic compound, as potential solvent systems in pharmaceutical industry applications, are studied. The densities and viscosities of the binary mixtures of 1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim][BF4]) with acetonitrile, N,N-dimethylacetamide, methanol, and N-methyl-2-pyrrolidone were measured at atmospheric pressure over the [C4mim][BF4] mole fraction range from 0.1 to 0.9 and at temperatures from 303.15 to 333.15 K at intervals of 10 K. The densities were measured using a vibrating-tube digital density meter and the viscosities were measured using a capillary viscometer. The excess molar volumes (VE) and viscosity deviations (Δη) were calculated from densities and viscosities of mixture, respectively, and fitted to the Redlich–Kister polynomial. The optimally fitted parameters are also determined and the correlation results are in satisfactory agreement with the experimental data. In addition, the excess molar volumes of binary mixtures of ionic liquid with different organic compounds are compared and discussed using the Hansen solubility parameter.

바이오 기반 ε-Caprolactam과 Morpholinone을 사용하여 중합한 나일론 6-모폴리논 랜덤 공중합체의 제조와 특성평가

Bio-based nylon 6-morpholinone random copolymers were prepared by the anionic ring opening polymerization of e-caprolactam and morpholinone, both of which were prepared from lysine and glucose, respectively. From this work, a new biomass based nylon 6 with improved hydrophilicity was prepared. Optimizing the polymerization condition, copolymer with a viscosity-average molecular weight of 30000 g/mol was prepared, with a yield of 80%. It was possible to improve the hydrophilicity of nylon 6 by its copolymerization with morpholinone. The prepared nylon 6-morpholinone random copolymers were then characterized using several analytical methods such as DSC, TGA, XRD, viscosity measurement with U-shaped glass capillary viscometer and contact angle measurement.

A feasibility study of in-line rheological characterisation of a wastewater sludge using ultrasound technology

The rheological characteristics of sludge affect transportation, treatment and the disposal processes involved in sludge system design and management operations such as dewatering, including flocculation and filtration. The concentration of solid matter in the sludge has an effect on rheological parameters such as yield stress and viscosity. These rheological properties of sludge are almost exclusively obtained today using commercially available instruments, such as conventional rotational rheometers or tube (capillary) viscometers. Since these methods are time-consuming and unsuitable for real-time process monitoring, the ultrasonic velocity profiling coupled with pressure drop (UVP+PD) methodology becomes very attractive for in-line flow behaviour monitoring for quality control and process optimisation. The main objective of this research work was to evaluate the UVP+PD technique in a concentrated sludge as found in a wastewater treatment plant. A portable pump test rig with tube viscometer fitted with a UVP+PD system was used to determine the rheological parameters. Conventional UVP installation techniques were tested as well as a new delay line UVP transducer. The results obtained from different installation techniques and transducers are compared. Finally, rheological parameters obtained using UVP+PD compared within 15% of that obtained using the tube viscometer. The results showed that UVP+PD is a feasible and promising technique for in-line real time flow visualisation and rheological characterisation for treated wastewater sludge which, when used as in-line process control, could lead to significant savings in chemicals and will optimise processes producing drier sludges and filter cakes.Keywords: Ultrasonic velocity profiling, UVP+PD methodology, sludge rheology, non-Newtonian, tube viscometry

Excess properties and viscous flow thermodynamics of the binary system 1,2-ethanediamine+triethylene glycol at T=(298.15, 303.15, 308.15, and 313.15) K for CO2 capture

Liquid densities and viscosities are reported for the binary system of 1,2-ethanediamine (EDA)+triethylene glycol (TEG) at T=(298.15, 303.15, 308.15, and 313.15) K. Densities were measured using a capillary pycnometer and viscosities were determined using an Ubbelohde capillary viscometer. The experimental results are compared with data published in the literatures. Based on the density data and kinematic viscosity data, excess molar volumes (V ) and deviation in kinematic viscosity (Δν) were calculated and the calculated results were fitted to a Redlich-Kister equation to obtain the coefficients and estimate the standard deviations between the experimental and calculated quantities. The values of V are negative in the whole composition range, whereas the values of Δν are positive over the major composition range. From kinematic viscosity data, Gibbs energies of activation of viscous flow (ΔG*), enthalpy of activation for viscous flow (ΔH*), and entropy of activation for the viscous flow (ΔS*) were also calculated.

Physicochemical studies and rheological modelling of Albizia lebbeck (AL) gum exudates

Purpose – The purpose of this study is to determine the physicochemical and rheological parameters of Albizia lebbeck gum. Design/methodology/approach – Physicochemical analysis was carried out using recommended methods. Gas chromatography mass spectrophotometer and Fourier transformed infra red (FTIR) analyses were carried out using their respective spectrophotometer. Scanning electron microscopy was carried out using scanning electron microscope, while rheological measurements were carried out using Ubbelohde capillary viscometer, digital Brookfield DV 1 viscometer and a rheometer. Findings – Albizia zygia gum is an ionic gum with unique physical and chemical properties. Scanning electron micrograph revealed that the internal structure of the gum is porous with irregular molecular arrangement. Thermodynamic parameters of viscous flow indicated the existence of few inter- and intra-molecular interactions, and the attainment of transition state was linked to bond breaking. Coil overlap transition studies revealed the existence of dilute and concentrated regimes. The viscosity of the gum was also found to decrease with decrease in the charge of cation (such that Al3+ &gt; Ca2+ &gt; K+) and with increase in ionic strength. Research limitations/implications – The paper provided information on physicochemical and rheological characteristics/behaviour of Albizia zygia gum, of Nigerian origin. From this information, possible application of this gum in the food and pharmaceutical industries can be deduced. Originality/value – The paper is original since information concerning Albizia zygia gum of Nigerian origin are not well documented as established in the work. It also adds values on the use of Albizia zygia gum, either on its own or in combination with other gums for industrial purpose.