Search

In this work, we explored how the structure of monolayer water confined between two graphene sheets is coupled to its dynamic behavior. Our molecular dynamics simulations show that there is a remarkable interrelation between the friction of confined water with two walls and its structure under extreme confinement. When the water molecules formed a regular quadrilateral structure, the friction coefficient is dramatically reduced. Such a low-friction coefficient can be attributed to the formation of long-range ordered hydrogen bond network, which not only decreases the structure corrugation in the direction perpendicular to the walls but also promotes the collective motion of the confined water. The regular quadrilateral structure can be formed only if the number density of confined water falls within a certain range. Higher number density results in larger structure corrugations, which increases the friction, while smaller number density leads to an irregular hydrogen bond network in which the collective motion cannot play the role. We demonstrated that there are four distinct stages in the diagram of the friction coefficient vs the number density of confined water. This research clearly established the connection between the dynamic characteristics of confined monolayer water and its structure, which is beneficial to further understand the mechanism of the high-speed water flow through graphene nanocapillaries observed in recent experiments. [ABSTRACT FROM AUTHOR]

TCL CSOT utilized inkjet printing technology to produce impressive medium and large‐size OLED products in the previous. In this work, high‐resolution notebook equipped with IGZO backplane is shown. This inkjet printing notebook offers 240 PPI along with good optical performance. Also, breakthrough in high‐resolution printing has been achieved, 274 PPI panel has been successfully printed. It is demonstrated that inkjet printing technology would adapt the trend of display products with various sizes toward higher resolution. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the effect of biaxial tensile strain on the osteogenic differentiation of rat bone marrow mesenchymal stem cells(rBMSCs)in vitro.The rBMSCs were isolated from tibia and femur of 4weeks-old Sprague-Dawley(SD)rats.The rBMSCs were cultured in DMEM-LG complete culture medium and grew to subconfluence in the cell culture device for loading tensile strain.The biaxial tensile strain was applied to the rBMSCs for periods of 2,4and 6hours every day,respectively,lasting 3days.The amplitude of biaxial tensile strain applied to the rBMSCs were 1%,2% and 5%respectively,at a frequency of 1Hz.Unstrained rBMSCs were used as blank control(control group).The rBMSCs cultured with DMEM-LG complete culture medium containing100nmol/Lβ-Estradiol(E2)were used as positive control.The mRNA expression of alkaline phosphatase(ALP),collagen typeⅠ(ColⅠ),Runt-related transcription factor 2(Runx2)and osteocalcin(OCN)was examined with real-time quantitative PCR and the protein expression of ALP,ColⅠ,Runx2 and OCN was detected with Western blot method.The results showed as follws:(1)The mRNA and protein expression of the ALP,ColⅠ,Runx2,OCN were significantly higher in rBMSCs of the E2 group than those in the control group(P<0.05).(2)The mRNA and protein expression level of the ALP,Runx2 were higher markedly in the 1% tensile strain groups than those in the control group(P<0.05),but lower than those in the E2group(P<0.05).(3)The mRNA and protein expression level of the ALP,ColⅠ,Runx2,OCN were significantly higher in the 2% tensile strain groups than those in the control group(P<0.05),and the mRNA and protein expression level of ColⅠ and Runx2 in the group applied with2% amplitude of tensile strain for 4h/d was significantly higher than those in E2group(P<0.05).(4)The mRNA and protein expression level of the ALP,ColⅠ,Runx2 were significantly higher in the groups applied with 5% amplitude of tensile strain for 2h/d or for 4h/d than those in the control group(P<0.05).In our study,E2 and mechanical stimulation played an important role in the regulation of differentiation of rBMSCs into osteoblasts,and the manner applied with the 2%amplitude of tensile strain for 4h/d,lasting 3days was an optimal stimulus for up-regulating the mRNA and protein expression of ALP,ColⅠ,Runx2,OCN of rBMSCs.

Unlabelled: Heterodimeric beta-galactosidase of Lactobacillus acidophilus belongs to glycoside hydrolase family 2, encoded by two overlapping and translational coupling genes, lacL and lacM. The lacL and lacM genes of the sequenced strain L. acidophilus NCFM encode polypeptides with calculated molecular masses of 73,253 and 35,817 Da, respectively., Objective: To clone, overexpress and characterize the enzyme in Escherichia coli., Methods: We cloned the fragment (2834 bp) containing ribose-binding site (RBS) and coding regions of the lacLM genes from L. acidophilus ATCC 4356 into expression vector pQE31. RBS and HIS-Tag of pQE31 were substituted by inserted fragment. Recombinant plasmid was electrotransformed into E. coli JM109. Expression product was purified by ammonium sulphate fractionation, anion-exchange, affinity chromatography and gel permeation. Native molecular mass of homogenous enzyme was measured by gel permeation, and beta-galactosidase activity was determined by using o-nitrophenyl-beta-D-galactopyranoside (ONPG) as the substrate., Results: Overexpression of the soluble enzyme in E. coli was achieved. Amino acid residue 512 of recombinant LacL was different from that of L. acidophilus NCFM. Homogenous enzyme was obtained by purification. The homogenous enzyme had a specific activity of 226 U/mg protein, a native molecular mass of 96.3+/-4.6 kDa, an optimum temperature at 49 degrees C and an optimum pH of 7. The Km and Vmax values of the enzyme were 2.18+/-0.12 mmol/L, 273+/-5 U/mg protein respectively.