Solvent-dependent conformation of a regioselective amylose carbamate: Amylose-2-acetyl-3,6-bis(phenylcarbamate)

This is the peer reviewed version of the following article: Maiko Tsuda, Ken Terao, Shinichi Kitamura, Takahiro Sato, “Solvent-dependent conformation of a regioselective amylose carbamate: Amylose-2-acetyl-3,6-bis(phenylcarbamate)”, Biopolymers, Volume 97, Issue 12, pages 1010–1017, December 2012, which has been published in final form at DOI: 10.1002/bip.22118. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving

Solvent-Dependent Conformation of Amylose Tris(Phenylcarbamate) as Deduced from Scattering and Viscosity Data

The z-average mean-square radius of gyration 〈S^2〉_z, the particle scattering function P(k), the second virial coefficient, and the intrinsic viscosity [η] have been determined for amylose tris(phenylcarbamate) (ATPC) in methyl acetate (MEA) at 25°C, in ethyl acetate (EA) at 33°C, and in 4-methyl-2-pentanone (MIBK) at 25°C by light and small-angle X-ray scattering and viscometry as functions of the weight-average molecular weight in a range from 2 × 10^4 to 3 × 10^6. The first two solvents attain the theta state, whereas the last one is a good solvent for the amylose derivative. Analysis of the 〈S^2〉_z, P(k), and [η] data based on the wormlike chain yields h (the contour length or helix pitch per repeating unit) = 0.37 ± 0.02 and λ^ (the Kuhn segment length) = 15 ± 2 nm in MEA, h = 0.39 ± 0.02 and λ^ = 17 ± 2 nm in EA, and h = 0.42 ± 0.02 nm and λ^ = 24 ± 2 nm in MIBK. These h values, comparable with the helix pitches (0.37–0.40 nm) per residue of amylose triesters in the crystalline state, are somewhat larger than the previously determined h of 0.33 ± 0.02 nm for ATPC in 1,4-dioxane and 2-ethoxyethanol, in which intramolecular hydrogen bonds are formed between the C[DOUBLE BOND]O and NH groups of the neighbor repeating units. The slightly extended helices of ATPC in the ketone and ester solvents are most likely due to the replacement of those hydrogen bonds by intermolecular hydrogen bonds between the NH groups of the polymer and the carbonyl groups of the solvent.This is the peer reviewed version of the following article: Taichi Fujii1, Ken Terao, Maiko Tsuda, Shinichi Kitamura, Takashi Norisuye, “Solvent-dependent conformation of amylose tris(phenylcarbamate) as deduced from scattering and viscosity data”, Biopolymers, Volume 91, Issue 9, pages 729–736, September 2009, which has been published in final form at DOI: 10.1002/bip.21219. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving

Solution Properties of Amylose Tris(Phenylcarbamate) : Local Conformation and Chain Stiffness in 1,4-Dioxane and 2-Ethoxyethanol

Light and small-angle X-ray scattering, sedimentation equilibrium, viscosity, circular dichroism, and infrared absorption measurements have been made on 1,4-dioxane (DIOX) and 2-ethoxyethanol (2EE) solutions of seven amylose tris(phenylcarbamate) samples ranging in molecular weight from 2 x 10^4 to 3 x 10^6. Analyses of gyration radius, scattering function, and intrinsic viscosity data in terms of the wormlike chain model yield Kuhn segment lengths of 22 ± 2 nm and 16 ± 2nm in DIOX and 2EE, respectively, and a contour length per residue of 0.33 ± 0.02 nm in both, showing that the amylose derivative chain has high stiffness and a contour length slightly shorter than the known value 0.37-0.40 nm for amylosetriesters in the crystalline state. These results are consistent with the intramolecular hydrogen bonding between the C=0 and NH groups of the neighbor repeating units detected by infrared absorption and also with the locally regular (or helical) conformation indicated by circular dichroism

Solution properties of amylose tris(3,5-dimethylphenylcarbamate) and amylose tris(phenylcarbamate): Side group and solvent dependent chain stiffness in methyl acetate, 2-butanone, and 4-methyl-2-pentanone

Five amylose tris(3,5-dimethylphenylcarbamate) (ADMPC) samples ranging in weightaverage molecular weight M w from 1.7 × 10 4 to 3.4 × 10 5 were studied by light and small-angle X-ray scattering, sedimentation equilibrium, and viscometry in methyl acetate (MEA), 2-butanone (MEK), and 4-methyl-2-pentanone (MIBK) at 25 °. Seven amylose tris(phenylcarbamate) (ATPC) samples whose M w ranges between 2 × 10 4 and 3×10 6 were also investigated in MEK at 25 °. The radii of gyration, particle scattering functions, and intrinsic viscosities determined as a function of M w were analyzed in terms of the cylindrical wormlike chain model mainly to determine the Kuhn segment length λ -1 and the contour length h (or the helix pitch) per residue. While the obtained h values (0.36-0.38 nm) of ADMPC are quite insensitive to the solvents, the λ -1 value not only is 1.5-3 times larger than that of ATPC in the corresponding solvent but also significantly increases with an increase of the molar volume of the solvent, and it reaches 73 nm in MIBK, which is the highest value for previously investigated phenylcarbamate derivatives of polysaccharides. This high stiffness is most likely due to the steric hindrance of the solvent molecules H-bonding with the NH groups of the polymer. © 2010 American Chemical Society.Tsuda M., Terao K., Nakamura Y., et al. Solution properties of amylose tris(3,5-dimethylphenylcarbamate) and amylose tris(phenylcarbamate): Side group and solvent dependent chain stiffness in methyl acetate, 2-butanone, and 4-methyl-2-pentanone. Macromolecules, 43(13), 5779-5784, June 11, 2010. Copyright © 2010, American Chemical Society. https://doi.org/10.1021/ma1006528

Bat Coronaviruses and Experimental Infection of Bats, the Philippines

Virus-infected fruit bats showed no signs of clinical infection

A quality management system aiming to ensure regulatory-grade data quality in a glaucoma registry.

BackgroundDisease/patient registries are underutilized despite their multiple advantages over clinical trials in the clinical evaluation of drugs, such as the capacity for long-term curation, provision of patient outcome data in routine clinical practice, and provision of benchmark data for comparison. Ensuring the fit-for-purpose quality of data generated from such registries is important to informing regulatory decision making. Here, we report the construction of a quality management system aiming to ensure regulatory-grade data quality for a registry of Japanese patients with glaucoma to evaluate long-term patient outcomes.MethodsThe quality management system was established by reference to the risk-based approach in the ICH-E6 (R2) recommendations. The following three-component approach was taken: establishment of governance, computerized system validation (CSV), and implementation of risk assessment and control. Compliance of the system with the recommendations of regulatory guidelines relevant to use of the registry was assessed.ResultsGovernance by academic collaboration was established. This was followed by the development of a total of 15 standard operating procedures, including CSV, data management, monitoring, audit, and management of imaging data. The data management system was constructed based on a data management plan, which specified data/paper flow and data management procedures. The electronic data capture (EDC) system was audited by an external vendor, and configured and validated using the V-model framework as recommended in the GAMP5 guideline. Informed consent, eligibility assessment and major ophthalmology measurements were determined as Critical to Quality (CTQ) factors. A total of 22 risk items were identified and classified into three categories, and operationalized in the form of a risk control plan, which included training sessions and risk-based monitoring. The glaucoma registry addressed most quality recommendations in official guidelines issued by multiple health authorities, although two recommendations were not met.ConclusionsWe established and configured a quality management system for a glaucoma registry to ensure fit-for-purpose data quality for regulatory use, and to curate long-term follow-up data of glaucoma patients in a prospective manner

The genomes of intracellur symbionts in deep-sea Calyptogena clams are still in an early phase of reductive genome evolution.

http://www.godac.jamstec.go.jp/darwin/cruise/yokosuka/yk09-12/ehttp://www.godac.jamstec.go.jp/darwin/cruise/yokosuka/yk11-04/ehttp://www.godac.jamstec.go.jp/darwin/cruise/natsushima/nt10-08/

Usefulness of Acoustic Monitoring of Respiratory Rate in Patients Undergoing Endoscopic Submucosal Dissection

Aim. The study assessed the usefulness of a recently developed method for respiratory rate (RR) monitoring in patients undergoing endoscopic submucosal dissection (ESD) under deep sedation. Methods. Study subjects comprised 182 consecutive patients with esophageal cancer or gastric cancer undergoing ESD. The usefulness of acoustic RR monitoring was assessed by retrospectively reviewing the patients’ records for age, gender, height, weight, past history, serum creatinine, RR before ESD, and total dose of sedative. Results. Respiratory suppression was present in 37.9% of (69/182) patients. Continuous monitoring of RR led to detection of respiratory suppression in all these patients. RR alone was decreased in 24 patients, whereas both RR and blood oxygen saturation were decreased in 45 patients. Univariate analysis showed female gender, height, weight, and RR before treatment to be significantly associated with respiratory suppression. Multivariate analysis showed RR before treatment to be the only significant independent predictor [odds ratio (OR) 0.83, 95% confidence interval (CI) 0.73–0.95, and P=0.006] of respiratory suppression. Conclusion. In this study, the difference in RR before treatment between patients with and without respiratory suppression was subtle. Therefore, we suggest that acoustic RR monitoring should be considered in patients undergoing ESD under sedation to prevent serious respiratory complications