Evidence of a Rod-like Structure for Hydroxypropyl Cellulose Samples in Aqueous Solution.

Because hydroxypropyl cellulose (HpC) is a popular polymeric material that forms a liquid crystalline phase in solutions with various kinds of solvents, including water, it is commonly thought that HpC has a typical rod-like structure in solution. In this study, the structures of commercial HpC samples in aqueous solution with average molar substitution numbers (MS) ranging from 3.6 to 3.

Rigid Rod-like Viscoelastic Behaviors of Methyl Cellulose Samples with a Wide Range of Molar Masses Dissolved in Aqueous Solutions.

The viscoelastic behaviors of aqueous solutions of commercially available methyl cellulose (MC) samples with a degree of substitution of 1.8 and a wide range of weight average molar masses () were investigated over a wide concentration () range at some temperatures from -10 to 25 °C. The viscoelastic parameters useful to discuss the structure and dynamics of MC-forming particles in aqueous solutions were precisely determined, such as the zero-shear viscosity (), the steady-state compliance (), the average relaxation time (), and the activation energy (*) of .

Structure and Conformation of Hydroxypropylmethyl Cellulose with a Wide Range of Molar Masses in Aqueous Solution─Effects of Hydroxypropyl Group Addition.

The structure of hydroxypropylmethyl cellulose (HpMC) samples with a wide range of weight average molar masses () from 23 to 5000 kg mol, a controlled degree of substitution () of 1.9 by methyl groups, and a molar substitution number () of 0.25 by hydroxypropyl groups dissolved in aqueous solution was examined using static light scattering (SLS), dynamic light scattering (DLS), small-to-wide angle neutron scattering (S-WANS) techniques, and intrinsic viscosity ([η]) measurements.

Conformation and Structure of Hydroxyethyl Cellulose Ether with a Wide Range of Average Molar Masses in Aqueous Solutions.

The solution properties of a water-soluble chemically modified cellulose ether, hydroxyethyl cellulose (HeC), were examined using static light scattering (SLS), dynamic light scattering (DLS), small-to-wide-angle neutron scattering (S-WANS), small-to-wide-angle X-ray scattering (S-WAXS) and viscometric techniques at 25 °C. The examined HeC samples had average molar substitution numbers ranging from 2.36 to 2.

Hydrogen-Bond Configurations of Hydration Water around Glycerol Investigated by HOH Bending and OH Stretching Analysis.

Toward a comprehensive understanding of the mechanism of glycerol as a moisturizer, studies on the hydrogen-bond (HB) structure of hydration water, which is known to be disordered by glycerol, are insufficient. To this aim, we evaluated the HB configurations based on the HOH bending and OH stretching spectra of the hydration water from those of glycerol/water mixtures by subtracting the contributions of bulk water and glycerol using dielectric relaxation spectroscopy. Analysis of the HOH bending band showed that hydration water-donating HBs lose the intermolecular bending coupling with increasing glycerol by replacing the water-water HBs with water-glycerol HBs.

Elongated Rodlike Particle Formation of Methyl Cellulose in Aqueous Solution.

The conformation and structure of methyl cellulose (MC) ether samples dissolved in pure water under dilute conditions were carefully reconsidered based on the results obtained using small-to-wide-angle neutron scattering (S-WANS), static light scattering (SLS), dynamic light scattering (DLS), and viscometric techniques. The examined MC samples possessed an average degree of substitution by methyl groups per glucose unit of ca 1.8 and weight average molar masses ( ), ranging from 23 to 790 kg mol.

Evidence of Long Two-Dimensional Folding Chain Structure Formation of Poly(vinylidene fluoride) in -Methylpyrrolidone Solution: Total Form Factor Determination by Combining Multiscattering Data.

Very recently, we proposed that poly(vinylidene fluoride) (PVDF) dissolves in a long rectangular column conformation induced by the formation of a two-dimensional folding chain structure in an -methylpyrrolidone (NMP) solution based on the results obtained from static light scattering (SLS), small- to wide-angle X-ray scattering (S-WAXS), and viscometric experiments. Small- to wide-angle neutron scattering (S-WANS) experiments were able to provide clear decisive evidence for the presence of such a two-dimensional folding chain structure in a deuterated (d)NMP solution of PVDF samples with two different weight average molar masses ( ) of 100 and 1200 kg mol, even under dilute conditions at concentrations less than the overlapping concentrations due to the quite high neutron scattering contrast obtained by using (d)NMP as a solvent. An increase in from 100 to 1200 kg mol substantially increases the particle length and width from = 80 to 350 nm and = 5.

First Observation of the Hydration Layer around Polymer Chain by Scattering and Its Relationship to Thromboresistance: Dilute Solution Properties of PMEA in THF/Water.

Poly(2-methoxyethyl acrylate) (PMEA) is known to exhibit excellent thromboresistance, i.e., hardly causing blood-clot formation on its surface.

Low Quality of Warfarin Therapy is Associated With Female Gender but Not With Polypharmacy in Patients With Atrial Fibrillation.

We examined the impact of polypharmacy on the quality of the anticoagulation therapy in patients with atrial fibrillation. We also examined the factors that affect the stability of warfarin therapy. This retrospective study was conducted using data from 157 consecutive outpatients with atrial fibrillation in a single tertiary referral hospital.

Hydration/Dehydration Behavior of Hydroxyethyl Cellulose Ether in Aqueous Solution.

Hydroxyethyl cellulose (HeC) maintains high water solubility over a wide temperature range even in a high temperature region where other nonionic chemically modified cellulose ethers, such as methyl cellulose (MC) and hydroxypropylmethyl cellulose (HpMC), demonstrate cloud points. In order to clarify the reason for the high solubility of HeC, the temperature dependence of the hydration number per glucopyranose unit, , for the HeC samples was examined by using extremely high frequency dielectric spectrum measuring techniques up to 50 GHz over a temperature range from 10 to 70 °C. HeC samples with a molar substitution number () per glucopyranose unit by hydroxyethyl groups ranging from 1.

Reconsideration of the conformation of methyl cellulose and hydroxypropyl methyl cellulose ethers in aqueous solution.

The structure and conformation of methyl cellulose (MC) and hydroxypropyl methyl cellulose (HpMC) ether samples dissolved in dilute aqueous (DO) solutions at a temperature of 25 °C were reconsidered in detail based on the experimental results obtained using small- and wide-angle neutron scattering (S-WANS) techniques in a range of scattering vectors () from 0.05 to 100 nm. MC samples exhibited an average degree of substitution (DS) by methyl groups per glucose unit of DS = 1.

Polypharmacy Is Associated With Accelerated Deterioration of Renal Function in Cardiovascular Outpatients.

Background: Polypharmacy is associated with poor prognosis of patients with various diseases. However, it has not been precisely addressed how polypharmacy affects the clinical characteristics of the cardiovascular outpatients. The aim of this study is to search for the clinical characteristics related to the number of prescribed drugs in the cardiovascular outpatients.

Molecular motions, structure and hydration behaviour of glucose oligomers in aqueous solution.

The degree of polymerization and temperature dependencies of the molecular motions, configuration and hydration behaviour of glucose oligomers (Gn, n = 2 to 7, degree of polymerization) in aqueous solutions were investigated using extremely high-frequency dielectric spectrum measuring techniques up to 50 GHz. The obtained dielectric spectra for the aqueous Gn solutions were well decomposed into four Debye-type relaxation modes. The fastest relaxation mode j = 1 was assigned to the rotational process of free water molecules in the sample solution.

Anti-parallel dimer and tetramer formation of cyclic and open structure tertiary amides, N-methyl-2-pyrrolidone and N,N-dimethylacetamide, in solution of a non-polar solvent, benzene.

We examined the dielectric (DE) and nuclear magnetic resonance (NMR) spectroscopic behaviour of N-methyl-2-pyrrolidone (NMP) and N,N-dimethylacetamide (DMAc), which are tertiary amide compounds that bear five-membered cyclic and open structures, respectively. They were examined to investigate the formation of anti-parallel dimers and tetramers in a dipole configuration in the pure liquid state and in benzene solution over a wide concentration range at 25 °C. Because the Kirkwood correlation factors of electric dipoles considerably decreased with increasing concentrations in both the NMP and DMAc systems and because the second DE relaxation modes were clearly observed to exhibit relaxation times that are longer than those of the first modes assigned to the rotational relaxation of monomeric molecules, anti-parallel dimers are formed due to dipole-dipole interactions with increasing concentrations.

Transport Properties of Commercial Cellulose Nanocrystals in Aqueous Suspension Prepared from Chemical Pulp via Sulfuric Acid Hydrolysis.

A cellulose nanocrystal (CNC) sample prepared from chemical pulp via sulfuric acid hydrolysis procedures has been supplied by InnoTech Alberta Inc. in the shape of white dry powder as a prototype product. Some transport coefficients were precisely investigated for the CNC sample in aqueous suspensions at the room temperature of 25 °C such as the average rotational and translational diffusion coefficients ( and ) and viscoelastic relaxation times (τ) at dilute conditions.

Relationship between global and segmental dynamics of poly(butylene oxide) studied by broadband dielectric spectroscopy.

Relationship between segmental relaxation and normal-mode relaxation has been studied for molten poly(butylene oxide)s having various molecular weights by broadband dielectric spectroscopy over a wide temperature (T) range. We found that T dependence of the segmental relaxation time, τ, was weaker than the normal mode time, τ, at high T(>250 K ∼ T + 50 K), and the τ/τ ratio systematically decreased with increasing temperature. This high temperature complexity, whose mechanism has not been discussed in detail so far, was quantitatively explained by assuming the two step processes: local conformation change of polymers (elementary process) occurs first, and then the motion of a segment unit (second process) occurs.

Pravastatin reduces radiation-induced damage in normal tissues.

Pravastatin is an inhibitor of 3-hydroxy-3-methyl- glutaryl-coenzyme A reductase that has been reported to have therapeutic applications in a range of inflammatory conditions. The aim of the present study was to assess the radioprotective effects of pravastatin in an experimental animal model. Mice were divided into two groups: The control group received ionizing radiation with no prior medication, while the pravastatin group received pravastatin prior to ionizing radiation.

Polaprezinc protects normal intestinal epithelium against exposure to ionizing radiation in mice.

Polaprezinc (PZ), an antiulcer drug, has been reported to have antioxidant effects. The purpose of the present study was to assess the radioprotective effects of PZ in the normal intestine of C57BL/6J mice. PZ was orally administered at 100 mg/kg body weight in the drinking water.

Pronounced Dielectric and Hydration/Dehydration Behaviors of Monopolar Poly(N-alkylglycine)s in Aqueous Solution.

Poly(N-methylglycine) (NMGn) and poly(N-ethylglycine) (NEGn) obtained by polymerization reactions initiated by benzylamine have no carboxy termini, such as those in normal polyamides, but have only amino termini, which exist primarily as cations in aqueous media at a pH value of ca. 9.5, observed in aqueous solutions without any buffer reagents.

Dangling OH Vibrations of Water Molecules in Aqueous Solutions of Aprotic Polar Compounds Observed in the Near-Infrared Regime.

Near-infrared (NIR) absorption spectrum measurements over a frequency range from 4000 to 12000 cm(-1) were employed to investigate the effects of the presence of solute compounds to vibrational modes of water molecules in aqueous solutions of some aprotic hydroneutral polar compounds with large dipole moments, such as nitro compounds and nitriles. The obtained NIR spectra for the aqueous solutions were decomposed into three components: free water, solute, and water molecules affected by the presence of solutes. Newly determined NIR spectra of affected water molecules were well-described with at least four absorption modes observed at 7040, 6850, 6450, and 5640 cm(-1) for both the nitro compounds and nitriles.

Polaprezinc reduces the severity of radiation-induced mucositis in head and neck cancer patients.

Polaprezinc (PZ), an antiulcer drug, has been reported to have antioxidant properties. The aim of the present study was to assess the feasibility and efficacy of administering PZ for radiation-induced mucositis in head and neck cancer patients. Patients with newly diagnosed head and neck cancer were enrolled in this prospective study.

Evidence of anti-parallel dimer formation of 4-cyano-4'-alkyl biphenyls in isotropic cyclohexane solution.

The formation of anti-parallel dimers of two liquid crystal forming 4-cyano-4'-alkyl biphenyls (nCB, n = 5 (pentyl) and n = 8 (octyl)) was confirmed in an isotropic cyclohexane solution (nCB-cH). In addition to high frequency dielectric relaxation (DR) measurements up to 50 GHz, fluorescence emission (FE) experiments in the wavelength range from 280 to 500 nm were carried out to investigate the molecular dynamics of the nCB molecules. The DR spectra of solutions at intermediate to high concentrations were comprised of two dynamic modes.

Use of proton pump inhibitors is associated with anemia in cardiovascular outpatients.

Background: Proton pump inhibitors (PPI) are frequently prescribed in combination with aspirin for preventing peptic ulcer in patients with atherosclerotic diseases. In contrast, long-term use of PPI has been suggested to be associated with iron or vitamin B12 deficiency. The effect of PPI on hemoglobin (Hb) concentration, however, has not been clarified in cardiovascular outpatients.

Are all polar molecules hydrophilic? Hydration numbers of nitro compounds and nitriles in aqueous solution.

The hydration numbers of typical aprotic polar substances bearing dipole moments larger than 3 D, such as nitro compounds and nitriles, were precisely determined in aqueous solution using high frequency dielectric relaxation techniques up to a frequency of 50 GHz at 25 °C. The hydration number is one of the most quantitative parameters for determining the hydrophilicity or hydrophobicity of a compound. The hydration numbers of various nitriles, such as acetonitrile, propionitrile and n-butyronitrile bearing cyano groups, were determined to be ca.