Hydrogen Production with High Evolution Rate and High Yield by Immobilized Cells of Hydrogen-producing Bacteria Strain B49 in a Column Reactor

To improve the hydrogen evolution rate in continuous hydrogen production of a fermentative hydrogen-producing bacteria strain B49 (AF481148 in EMBL), 4% immobilized cells by polyvinyl alcohol-boric acid method, with the addition of a small amount of calcium alginate in a column reactor obtain hydrogen yield of 2.31 mol H2/mol glucose and hydrogen evolution rate of 1435.4 ml/L culture&middoth respectively at medium retention time of 2 h with a medium containing l0 g glucose/L. As the cell density in gel beads is increased to 8%, hydrogen yield and hydrogen evolution rate for l0 g glucose/L are 2.34 mol H2/mol glucose and 2912.4 ml/L culture &middot h respectively at medium retention time of 1 h, and for molasses wastewater COD of 7505.9 mg/L hydrogen production potential of 205.6 ml/g COD and hydrogen evolution rate of 2057.7 ml/L culture&middoth at hydraulic retention time of 0.75 h are observed. In the continuous culture pH value keeps around 3.9 by self regulation.

Superresolution imaging of DNA tetrahedral nanostructures in cells by STED method with continuous wave lasers

DNA tetrahedral nanostructures are considered to be uew nanocarriers because they can be precisely controlled and hold excellent penetration ability to the cellular membrane. Although the DNA tetrahedral nanostructure is extensively studied in biology and medicine, its behavior in the cells with nanoscale resolution is not understood clearly. In this letter, we demonstrate superrcsolution fluorescence imaging of the distribution of DNA tetrahedral nanostructures in the cell with a simulated emission depletion （STED） microscope, which is built based on a conventional eonfocal microscope and can t）rovide a resolution of 70 nm.

Theoretical aspects of selecting repeated unit cell model in micromechanical analysis using displacement-based finite element method

Repeated Unit Cell（RUC）is a useful tool in micromechanical analysis of composites using Displacement-based Finite Element（DFE）method,and merely applying Periodic Displacement Boundary Conditions（PDBCs）to RUC is almost a standard practice to conduct such analysis.Two basic questions arising from this practice are whether Periodic Traction Boundary Conditions（PTBCs,also known as traction continuity conditions）are guaranteed and whether the solution is independent of selection of RUCs.This paper presents the theoretical aspects to tackle these questions,which unify the strong form,weak form and DFE method of the micromechanical problem together.Specifically,the solution’s independence of selection of RUCs is dealt with on the strong form side,PTBCs are derived from the weak form as natural boundary conditions,and the validity of merely applying PDBCs in micromechanical Finite Element（FE）analysis is proved by referring to its intrinsic connection to the strong form and weak form.Key points in the theoretical aspects are demonstrated by illustrative examples,and the merits of setting micromechanical FE analysis under the background of a clear theoretical framework are highlighted in the efficient selection of RUCs for Uni Directional（UD）fiber-reinforced composites.

How to use progestin in hormone replacement therapy: an animal experiment

Objective To determine whether continuous or cyclic hormone replacement therapy (estrogen and progestogen) is better.Methods One hundred and forty Sprague-Dawley rats were randomly divided into seven groups. The 1st and 2nd groups were normal estrous and ovariectomy (OVX) controls. Treatment of the other groups imitated the clinical regimen (continuous and cyclic) with estradiol valerate (E2V) and medroxy progesterone (MPA) in different ratios of combination. The rats were sacrificed and sections of uterus were stained with HE and histochemical metheds to detect mitosis and proliferating cell nuclear antigen (PCNA), respectively. The mitotic index (MI) and PCNA index were calculated.Results The MI and PCNA index were similar in luminal and glandular cells. Both markers were low in the two control groups. When E2V was given for 1 to 6 days, both the MI and PCNA index increased with duration of treatment. When MPA was added, both markers were reduced to a very low level. In the continuous regimen, both markers decreased as the MPA dosage increased. The ratio of E2V∶MPA=1∶0.5 was enough to suppress markers to a low level similar to that of normal estrous rats. A further increase in the ratio to 1∶1.0 showed no further decrease in PCNA index. In the cyclic regimen, MPA was added for the last 5 days. The mitotic index reached a significantly low level near 0 in all ratios, but the PCNA index in each subgroup was still as high as the positive control, even though the dosage of MPA was increased several times to 1∶8.0. When MPA was added for the last 10 days, the PCNA index at a ratio of 1∶4.0 could be reduced to a low level.Conclusion The results of this study suggest that the continuous regimen was better than the cyclic regimen in postmenopausal hormone replacement therapy (HRT). Progestin should be given for at least 10 days in the cyclic regimen.