Prominent Intrinsic Proton Conduction in Two Robust Zr/Hf Metal-Organic Frameworks Assembled by Bithiophene Dicarboxylate.

To date, developing crystalline proton-conductive metal-organic frameworks (MOFs) with an inherent excellent proton-conducting ability and structural stability has been a critical priority in addressing the technologies required for sustainable development and energy storage. Bearing this in mind, a multifunctional organic ligand, 3,4-dimethylthiophene[2,3-b]thiophene-2,5-dicarboxylic acid (H2DTD), was employed to generate two exceptionally stable three-dimensional porous Zr/Hf MOFs, [Zr6O4(OH)4(DTD)6]·5DMF·H2O (Zr-DTD) and [Hf6O4(OH)4(DTD)6]·4DMF·H2O (Hf-DTD), using solvothermal means. The presence of Zr6 or Hf6 nodes, strong Zr/Hf-O bonds, the electrical influence of the methyl group, and the steric effect of the thiophene unit all contribute to their structural stability throughout a wide pH range as well as in water. Their proton conductivity was fully examined at various relative humidities (RHs) and temperatures. Creating intricate and rich H-bonded networks between the guest water molecules, coordination solvent molecules, thiophene-S, -COOH, and -OH units within the framework assisted proton transfer. As a result, both MOFs manifest the maximum proton conductivity of 0.67 × 10-2 and 4.85 × 10-3 S·cm-1 under 98% RH/100 °C, making them the top-performing proton-conductive Zr/Hf-MOFs. Finally, by combining structural characteristics and activation energies, potential proton conduction pathways for the two MOFs were identified.

Four Lanthanide(III) Metal-Organic Frameworks Fabricated by Bithiophene Dicarboxylate for High Inherent Proton Conduction.

Currently, it is still a challenge to directly achieve highly stable metal-organic frameworks (MOFs) with superior proton conductivity solely through the exquisite design of ligands and the attentive selection of metal nodes. Inspired by this, we are intrigued by a multifunctional dicarboxylate ligand including dithiophene groups, 3,4-dimethylthieno[2,3-b]thiophene-2,5-dicarboxylic acid (H2DTD), and lanthanide ions with distinct coordination topologies. Successfully, four isostructural three-dimensional lanthanide(III)-based MOFs, [Ln2(DTD)3(DEF)4]·DEF·6H2O [LnIII = TbIII (Tb-MOF), EuIII (Eu-MOF), SmIII (Sm-MOF), and DyIII (Dy-MOF)], were solvothermally prepared, in which the effective proton transport will be provided by the coordinated or free solvent molecules, the crystalline water molecules, and the framework components, as well as a large number of highly electronegative S and O atoms. As expected, the four Ln-MOFs demonstrated the highest proton conductivities (σ) being 0.54 × 10-3, 3.75 × 10-3, 1.28 × 10-3, and 1.92 × 10-3 S·cm-1 for the four MOFs, respectively, at 100 °C/98% relative humidity (RH). Excitingly, Dy-MOF demonstrated an extraordinary ultrahigh σ of 1 × 10-3 S·cm-1 at 30 °C/98% RH. Additionally, the plausible proton transport mechanisms were emphasized.

A community-based sero-epidemiological study of hepatitis B infection in Lianyungang, China, 2010.

INTRODUCTION: The 2010 targets of the China Hepatitis B Prevention Programme were a prevalence of hepatitis B surface antigen (HBsAg) less than 1.0% for children less than five years old and less than 6.0% for the total population. This survey assessed the prevalence of Hepatitis B infection in Lianyungang, Jiangsu province, China in 2009-2010. METHODS: Multistage sampling was used with 2372 subjects among 17 selected villages. Blood specimen collection and testing by enzyme-linked immunosorbnet assay (ELISA) were completed using the following markers for hepatitis infection: HBsAg and antibody to HBsAg (anti-HBs); hepatitis B e antigen (HBeAg) and antibody to HBeAg (anti-HBe); and hepatitis B core antibody (total anti-HBc). The data were analysed with Epi Info, version 3.3.2. RESULTS: The prevalence of HBsAg was 2.4% (95% Confidence Interval [CI]: 1.8-3.0; Adjusted Prevalence [AP] 2.9%); anti-HBs prevalence was 51.1% (95% CI: 49.1-53.1; AP 49.2%) and total anti-HBc prevalence was 41.7% (95% CI: 39.8-43.7; AP 45.5%). The prevalence of HBsAg and total anti-HBc positivity increased from young to older age groups, yet the prevalence of anti-HBs positivity decreased from young to older age groups (P < 0.001 for all). There was no difference in the prevalences of HBsAg and anti-HBs among females and males (P = 0.108 and 0.089), but females had a higher prevalence than males for total anti-HBc positivity (P < 0.001). DISCUSSION: This survey showed that in 2010 the prevalence of HBsAg among children aged less than five years was lower than the national target of 1.0% and that the prevalence of HBsAg for the total population was lower than the national target of 6.0%.

Analysis and applications of accommodative lenses for vision corrections.

Analysis and applications of vision correction via accommodating intraocular lens (AIOL) are presented. By Gaussian optics, analytic formulas for the accommodation rate function (M) for two-optics and three-optics systems are derived and compared with the exact numerical results. In a single-optics AIOL, typical value of M is (0.5-1.5) D∕mm, for an IOL power of (10-20) diopter. For a given IOL power, higher M is achieved in positive-IOL than negative-IOL. In the dual-optics AIOL, maximum accommodation is predicted when the front positive-optics moves toward the corneal plan and the back negative-optics moves backward. Our analytic formulas predict that greater accommodative rate may be achieved by using a positive-powered front optics, a general feature when either front or back optics is mobile. The M function is used to find the piggy-back IOL power for customized design based on the individual ocular parameters. Many of the new features demonstrated in this study can be easily realized by our analytic formulas, but not by raytracing method.