An Adversarial Dual-Branch Network for Nonhomogeneous Dehazing in Tunnel Construction.

The tunnel construction area poses significant challenges for the use of vision technology due to the presence of nonhomogeneous haze fields and low-contrast targets. However, existing dehazing algorithms display weak generalization, leading to dehazing failures, incomplete dehazing, or color distortion in this scenario. Therefore, an adversarial dual-branch convolutional neural network (ADN) is proposed in this paper to deal with the above challenges. The ADN utilizes two branches of the knowledge transfer sub-network and the multi-scale dense residual sub-network to process the hazy image and then aggregate the channels. This input is then passed through a discriminator to judge true and false, motivating the network to improve performance. Additionally, a tunnel haze field simulation dataset (Tunnel-HAZE) is established based on the characteristics of nonhomogeneous dust distribution and artificial light sources in the tunnel. Comparative experiments with existing advanced dehazing algorithms indicate an improvement in both PSNR (Peak Signal-to-Noise Ratio) and SSIM (Structural Similarity) by 4.07 dB and 0.032 dB, respectively. Furthermore, a binocular measurement experiment conducted in a simulated tunnel environment demonstrated a reduction in the relative error of measurement results by 50.5% when compared to the haze image. The results demonstrate the effectiveness and application potential of the proposed method in tunnel construction.

A study on the catalytic activity of polypeptides toward the hydrolysis of glucoside compounds gastrodin, polydatin and esculin.

The self-assembly of a series of catalytically active polypeptides toward hydrolysis of glucoside compounds, namely, gastrodin, polydatin and esculin was investigated. These active peptides are composed of two functional fragments: one is the hydrophobic sequence LHLHLRL, which forms assembling segments in the presence of Zn ions (Zn2+); another functional sequence of active peptides are catalytic sites such as Glu (E), Asp (D) and His (H), where carboxylic acids (-COOH) or imidazole groups act like scissors to cleave glucoside bonds of the compounds (according to the acid-base coupling mechanism). The effects of the amino acid sequence of the peptide, Zn2+ concentration, pH and the size or steric hindrance of glucoside compounds on the hydrolytic activity were studied. It was found that the crystalline structure of assembled peptides was crucial to provide the peptide with catalytic hydrolytic activity. Noncovalent interaction index was used to analyse the noncovalent interaction of PEs with glucoside compounds, including hydrogen bonds, van der Waals, and steric effect in the complexes. The binding energy of complexes, the direction and site of nucleophilic attack during deglycosylation processes were also investigated by molecular docking and the electron density Laplace function. This revealed that the differences in the hydrolytic activity of peptides toward glucoside compounds with different sizes originated from different hydrogen bond interactions between the peptides and substrates. These active peptides may find application in the preparation of drugs by de-glycosylation of natural compounds.

Detection of heterocyclic amine (PhIP) by fluorescently labelled cucurbit[7]uril.

Heterocyclic amines (HCA) are the main mutagenic factors in cooked meat products and are considered to be hazardous chemicals in the field of food safety. In this study, inspired by the "host-guest" interaction mechanism, a new technique for detecting 2-amino-1-methyl-6-phenylimidazo [4,5-b] pyridine (PhIP) was developed, taking advantage of the molecular cavities of cucurbit[7]uril (CB[7]) and the powerful guest recognition properties between CB[7] and PhIP. Based on this recognition mechanism, three steps were included in the detection procedure: firstly, regenerated cellulose (RC) membrane was oxidized by NaIO4 to generate aldehyde groups; secondly, the PhIP molecules to be detected were trapped by the aldehyde groups via amine-aldehyde conjugation chemistry; thirdly, the RC membrane with trapped PhIP was immersed into solutions of dansyl chloride-labelled CB[7] to allow the host-guest interaction to occur, so that PhIP could be quantified by fluorescence of the dansyl chloride dye. The limit of detection, linear range and recovery of this method were about 0.224 µg kg-1, 10-1000 nM and 89.0-96.4%, respectively. So far, most reported techniques for HCA detection are based on HPLC coupled with mass spectroscopy, and the method reported here might be the first quick measurement technique for HCA and may find wide application in food safety detection.

Diffusion interface layer controlling the acceptor phase of bilayer near-infrared polymer phototransistors with ultrahigh photosensitivity.

The narrow bandgap of near-infrared (NIR) polymers is a major barrier to improving the performance of NIR phototransistors. The existing technique for overcoming this barrier is to construct a bilayer device (channel layer/bulk heterojunction (BHJ) layer). However, acceptor phases of the BHJ dissolve into the channel layer and are randomly distributed by the spin-coating method, resulting in turn-on voltages (Vo) and off-state dark currents remaining at a high level. In this work, a diffusion interface layer is formed between the channel layer and BHJ layer after treating the film transfer method (FTM)-based NIR phototransistors with solvent vapor annealing (SVA). The newly formed diffusion interface layer makes it possible to control the acceptor phase distribution. The performance of the FTM-based device improves after SVA. Vo decreases from 26 V to zero, and the dark currents decrease by one order of magnitude. The photosensitivity (Iph/Idark) increases from 22 to 1.7 × 107.

Reassortment with dominant chicken H9N2 influenza virus contributed to the fifth H7N9 virus human epidemic.

H9N2 Avian influenza virus (AIV) is regarded as a principal donor of viral genes through reassortment to co-circulating influenza viruses that can result in zoonotic reassortants. Whether H9N2 virus can maintain sustained evolutionary impact on such reassortants is unclear. Since 2013, avian H7N9 virus had caused five sequential human epidemics in China; the fifth wave in 2016-2017 was by far the largest but the mechanistic explanation behind the scale of infection is not clear. Here, we found that, just prior to the fifth H7N9 virus epidemic, H9N2 viruses had phylogenetically mutated into new sub-clades, changed antigenicity and increased its prevalence in chickens vaccinated with existing H9N2 vaccines. In turn, the new H9N2 virus sub-clades of PB2 and PA genes, housing mammalian adaptive mutations, were reassorted into co-circulating H7N9 virus to create a novel dominant H7N9 virus genotype that was responsible for the fifth H7N9 virus epidemic. H9N2-derived PB2 and PA genes in H7N9 virus conferred enhanced polymerase activity in human cells at 33°C and 37°C, and increased viral replication in the upper and lower respiratory tracts of infected mice which could account for the sharp increase in human cases of H7N9 virus infection in the 2016-2017 epidemic. The role of H9N2 virus in the continual mutation of H7N9 virus highlights the public health significance of H9N2 virus in the generation of variant reassortants of increasing zoonotic potential.IMPORTANCEAvian H9N2 influenza virus, although primarily restricted to chicken populations, is a major threat to human public health by acting as a donor of variant viral genes through reassortment to co-circulating influenza viruses. We established that the high prevalence of evolving H9N2 virus in vaccinated flocks played a key role, as donor of new sub-clade PB2 and PA genes in the generation of a dominant H7N9 virus genotype (G72) with enhanced infectivity in humans during the 2016-2017 N7N9 virus epidemic. Our findings emphasize that the ongoing evolution of prevalent H9N2 virus in chickens is an important source, via reassortment, of mammalian adaptive genes for other influenza virus subtypes. Thus, close monitoring of prevalence and variants of H9N2 virus in chicken flocks is necessary in the detection of zoonotic mutations.

A D200N hemagglutinin substitution contributes to antigenic changes and increased replication of avian H9N2 influenza virus.

Influenza virus hemagglutinin (HA) plays an important role in viral antigenicity, replication and host range. However, few amino acid positions in HA were reported to play multiple functions in both viral antigenicity and replication. In the present study, through analyzing the amino acid sequences of H9N2 avian influenza viruses (AIVs) isolated from China, we identified a multi-functional substitution of D200N in HA1 protein. Firstly, the substitution of D200N changed the antigenicity of H9N2 AIVs. Secondly, the D200N increased the HA cleavage efficiency and reduced acid and thermal stability of HA protein, which triggered viral-endosomal membrane fusion whereby promoted the release of viral genome into the host cytoplasm. Finally, residue 200-N increased the replication of H9N2 viruses in both chicken embryo fibroblast (CEF) cells and chicken embryonated eggs. In summary, the D200N substitution is a newly identified antigenicity and replication determinant of H9N2 AIVs, which should be paid more attention during surveillance.

Photodynamic and photothermal synergistic behavior of triphenylamine-porphyrin nanoparticles for DNA interaction, cellular cytotoxicity and localization.

In this paper, amphiphilic conjugated triphenylamine-porphyrins TPA-Por-TPA and TPA-Por were designed and synthesized. The water-soluble nanostructures TPA-Por-TPA NPs and TPA-Por NPs spontaneously assembled after π-π stacking, which can be changed by improving the internal transfer ability of electrons. The intercalation and external binding modes of these free porphyrins and nanoporphyrins interacting with ct-DNA were confirmed by UV-vis and fluorescence spectroscopy. Reactive oxygen species (ROS) production was studied by 2',7'-dichlorofluorescein diacetate, demonstrating that the rate of production of ROS is TPA-Por-TPA NPs > TPA-Por-TPA > TPA-Por NPs > TPA-Por. In addition, the structure of the NP enhanced the acceptor-donor conjugated structure, resulting in fluorescence quenching and promoting non-radiative heat generation. The photothermal conversion efficiencies of the TPA-Por-TPA NPs and TPA-Por NPs were measured and calculated to be 34.89% and 37.99%, respectively. At the same time, the three nanomaterials showed good photocytotoxicity, and the IC50 of the TPA-Por-TPA NPs and TPA-Por NPs was 32.18 and 36.62 µg ml-1, respectively, at 10 min after laser irradiation. The cellular uptake and subcellular localization of these NPs were further evaluated through a confocal laser scanning microscope. The results showed that the conjugated NPs have good biocompatibility properties in the cancer cells. These properties make it possible for triphenylamine porphyrin NPs to become photosensitizers for the photodynamic and photothermal synergistic treatment of tumors, and have potential prospects for applications in cancer diagnosis and treatment.

Infection of chicken H9N2 influenza viruses in different species of domestic ducks.

Domestic ducks are considered as the interface between wild aquatic birds and terrestrial poultry and play an important role in the transmission and evolution of avian influenza viruses (AIVs). However, the infectivity of H9N2 AIVs in different domestic duck species has not been systematically evaluated. Here we investigated the infectivity of various genotypes of chicken H9N2 AIVs in Pekin duck (Anas Platyrhynchos), Mallard duck (Anas Platyrhynchos) and Muscovy duck (Cairina Moschata) through intranasal inoculation. We found that Pekin ducks and Mallard ducks were generally resistant to chicken H9N2 virus infection, while Muscovy ducks were relatively susceptible to H9N2 AIVs. All the tested viruses were isolated from oropharynx, trachea and lung tissues of Muscovy ducks. Additionally, genotype 57 (G57) H9N2 AIVs, which was predominant in chickens since 2010, showed increased virus replication in this duck species, indicating an improved interspecies transmission ability of recent H9N2 viruses from chickens to ducks. Our results demonstrated the role of Muscovy ducks in the ecology of H9N2 AIVs. More attentions should be paid to this host during viral surveillances. Additionally, inactivated H9N2 vaccine may be unnecessarily used in Pekin and Mallard ducks.

Genetic evolution of influenza H9N2 viruses isolated from various hosts in China from 1994 to 2013.

Influenza H9N2 subtype viruses and their reassortants (such as H7N9) are posing increasing threats to birds and humans in China. During 2009-2013, multiple novel subtype viruses with H9N2 original genes emerged in China. Yet, the genetic evolution of H9N2 viruses in various host organisms in China has not been systematically investigated since 2009. In the present study, we performed large-scale sequence analysis of H9N2 viral genomes from public databases, representing the spectrum of viruses isolated from birds, mammals and humans in China from 1994 to 2013, and updated the clade classification for each segment. We identified 117 distinct genotypes in 730 H9N2 viruses. We analyzed the sequences of all eight segments in each virus and found three important time points: the years 2000, 2006 and 2010. In the periods divided by these years, genotypic diversity, geographic distribution and host range changed considerably. Genotypic diversity fluctuated greatly in 2000 and 2006. Since 2010, a single genotype became predominant in poultry throughout China, and the eastern coastal region became the newly identified epidemic center. Throughout their 20-year prevalence in China, H9N2 influenza viruses have emerged and adapted from aquatic birds to chickens. The minor avian species and wild birds exacerbated H9N2 genotypes by providing diversified genes, and chickens were the most prevalent vector in which the viruses evolved and expanded their prevalence. It is the necessity for surveillance and disease control on live-bird markets, poultry farms and wild-bird habitats in China.

The glucose RQ-feedback control leading to improved erythromycin production by a recombinant strain Saccharopolyspora erythraea ZL1004 and its scale-up to 372-m(3) fermenter.

In this paper, glucose respiratory quotient (RQ)-feedback control was developed for erythromycin production with a recombinant strain Saccharopolyspora erythraea ZL1004. RQ was confirmed to be an ideal online parameter for regulating glucose feed rate. Through feeding glucose to control RQ at 0.85 during 45-100 h and 0.95 during 100-185 h, erythromycin titer and erythromycin A concentration were reached 11.88 and 8.82 g l(-1) in 50 l fermenter, which were increased by 8.3 and 6.1 % as compared to that with glucose pH-feedback control, respectively. When glucose RQ-feedback control was scaled up to 372-m(3) fermenter, erythromycin titer and erythromycin A concentration at 155 h were reached 9.12 and 7.12 g l(-1), respectively, which were 10.5 and 9.4 % higher than that with the original technology (glucose pH-feedback control). To the best of our knowledge, this is the first report on the successful application of glucose RQ-feedback control in erythromycin production, especially in 372-m(3) fermenter.