Evaluation of the Influence of Aquatic Plants and Lake Bottom on the Remote-Sensing Reflectance of Optically Shallow Waters

Aquatic plants and lake bottoms in optically shallow waters (OSWs) wield great influence on reflectance spectra, resulting in the inapplicability of most existing bio-optical models for water colour remote sensing in lakes. Based on radiative transfer theory and measured spectra from a campaign for Lake Taihu in October 2008, absorption and backscattering coefficients were used to simulate the remote-sensing reflectance, which are considered to be reliable if matched to their measured counterparts. Several cases of measured spectra at different depths, Secchi disk depth transparency, and aquatic plant height and coverage were analyzed thoroughly for spectral properties. The contribution of aquatic plants was evaluated and compared with the measured and simulated remote-sensing reflectance values. This is helpful for removing the influence of aquatic plants and lake bottoms from the spectra and for constructing an improved chlorophyll a retrieval model for OSWs, such as that for Lake Taihu, China

A multi-layer genome mining and phylogenomic analysis to construct efficient and autonomous efflux system for medium chain fatty acids

Medium-chain fatty acids (MCFAs) are important components for food, pharmaceutical and fuel industries. Nevertheless, engineering microorganisms to produce MCFAs often induces toxicity and stresses towards host strains, which could be alleviated via accelerating the export of MCFAs from cells. However, current secretory systems are inefficient and require inducible promoters. Here, a multi-layer genome mining and phylogenomic analysis was developed to identify efficient efflux transporters. Firstly, based on the genomic mining of 397 strains throughout various representative species, the evolutionary history of efflux transporters was recapitulated, and further experimental analysis revealed that acrE from Citrobacter exhibited the best performance. Secondly, according to the further mining of 797 Citrobacter genomes and 1084 Escherichia genomes, a detailed phylogenomic analysis of efflux transporter-centric genomic vicinities was performed. This led to the identification of efficient efflux pump combination acrE and acrF. These efflux pumps were then combined with the quorum-sensing circuit from Enterococcus faecalis to regulate MCFA efflux in an autonomous manner, which achieved a 4.9-fold boost in MCFA production and firstly demonstrated the efficient and autonomous efflux pump specially for MCFAs. The integrative omics technologies described here are enabling the utilization of the increasingly large database and the effective mining of target gene diversities

Improving Performance of All-Polymer Solar Cells Through Backbone Engineering of Both Donors and Acceptors

All-polymer solar cells (APSCs), composed of semiconducting donor and acceptor polymers, have attracted considerable attention due to their unique advantages compared to polymer-fullerene-based devices in terms of enhanced light absorption and morphological stability. To improve the performance of APSCs, the morphology of the active layer must be optimized. By employing a random copolymerization strategy to control the regularity of the backbone of the donor polymers (PTAZ-TPDx) and acceptor polymers (PNDI-Tx) the morphology can be systematically optimized by tuning the polymer packing and crystallinity. To minimize effects of molecular weight, both donor and acceptor polymers have number-average molecular weights in narrow ranges. Experimental and coarse-grained modeling results disclose that systematic backbone engineering greatly affects the polymer crystallinity and ultimately the phase separation and morphology of the all-polymer blends. Decreasing the backbone regularity of either the donor or the acceptor polymer reduces the local crystallinity of the individual phase in blend films, affording reduced short-circuit current densities and fill factors. This two-dimensional crystallinity optimization strategy locates a PCE maximum at highest crystallinity for both donor and acceptor polymers. Overall, this study demonstrates that proper control of both donor and acceptor polymer crystallinity simultaneously is essential to optimize APSC performance

Ganglioside GD2 is a potential candidate marker for lung cancer stem cells

Objective To explore the feasibility of ganglioside GD2 as a marker for lung cancer stem cells (LCSCs). Methods Cancer stem cells (CSCs) of lung cancer cell lines were enriched by spheroid culturing in vitro; The expression of stemness-related genes and GD3 synthase (GD3S) in LCSCs were detected by RT-qPCR and Western blot; The expression of GD2 and other stemness phenotypes in lung cancer cell line A549 were detected by flow cytometry; Cell proliferation was detected by CCK8 assay; Cell invasion and migration in vitro were examined by Transwell and wound healing assays; The oncogenicity of different subpopulations in cell line A549 was compared with tumor xenograft model. Results CSCs of A549 cell were successfully enriched by and the percentage of GD2+ cells was 0.57% in adherent cell, but the percentage of GD2+ cells was able to increase to 20.4% after spheroid culturing. In comparison with GD2- A549 cells, GD2+ A549 cells showed significantly enhanced cell proliferation (P＜0.05),invasion (P＜0.05) and migration ability (P＜0.01) in vitro. There was a close association between GD2 and two other LCSCs phenotypes, and the expression level of GD2 was positively correlated with the expression of CD44 (P＜0.01) and EpCAM (P＜0.001). The results in vivo indicated that tumors formed by GD2+ A549 cells grew faster (P＜0.001) and were more malignant (P＜0.01) as compared to GD2- A549 cells. Conclusions Ganglioside GD2 is a potential marker for LCSCs to identify cancer stem cells, providing a novel strategy of GD2-targeted lung cancer immunothearapy

Changes in human parechovirus profiles in hospitalized children with acute gastroenteritis after a three-year interval in Lanzhou, China.

The changing profile of infection over time for Human Parechoviruses (HPeVs) is not well known and no detailed study has been reported to date in China. This investigation on HPeV infection in hospitalized children in Lanzhou, China revealed variations in epidemiological characteristics after a three-year interval. To assess the changes that had occurred, epidemiological and clinical characteristics of HPeVs were characterized and compared with previously reported data by our group. A comparable positivity rate (25.3%, 73/289) was revealed after the three-year interval with the majority of the infected children (95.9%, 70/73) being younger than two years of age. While a temporal change in the seasonal distribution was noted in the current study, HPeVs were more frequently detected during July to November compared to September to December in the previous study. Changes in HPeV genotypes patterns, a temporal change in the prevalence of HPeV1, a younger susceptible age to HPeV3 compared with HPeV1 and a tendency of older children to be infected with HPeV4 are in contrast to our previous report. HPeV2, a rarely reported genotype, was identified for the first time in China. In addition, an exclusive trinucleotide (GAT) insertion in the HPeV4 nucleotide sequence was identified. However, the profiles of co-infection with other enteric related viruses were similar to our previous findings. In summary, these data suggest temporal variation in the seasonal distribution of HPeV and changing patterns of HPeV genotypes over time in the study region

Seasonal distribution of HPeV-positive samples.

<p>Incidence means HPeV positive cases per month, prevalence means HPeV positive rate per month.</p

Nucleic acid phylogenetic tree based on the VP3/VP1 conjunction region.

<p>The phylogenetic analyses were conducted in MEGA5 by using the Neighbor-Joining method. The p-distance method was applied to compute the evolutionary distances. LV was used as outgroup. A bootstrap test was replicated 1000 times and only the bootstrap values >70 are displayed. The reference strains are shown with their individual GenBank accession number and corresponding genotype.</p