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NiO-TiO 2 may be deemed as the preeminent resilient and cost-effective photocatalyst for the co-generated generation of hydrogen and value-added commodities via glycerol photoreforming. This assertion is founded on the fact that this composite catalyst possesses photochemical qualities, which enable it to effectively convert water & glycerol solution into hydrogen and other high-value added chemicals, which can be reliable option for industrial-scale glycerol photoreforming applications. [Display omitted] Selective photocatalysis to simultaneously produce sustainable hydrogen and value-added chemicals from biomass or biomass derivates is attracting extensive investigations. However, the lack of bifunctional photocatalyst greatly limits the possibility to realize the "one stone kills two birds" scenario. Herein, anatase titanium dioxide (TiO 2) nanosheets are rationally designed as the n-type semiconductor, combining with nickel oxide (NiO) nanoparticles, the p-type semiconductor, resulting in the formation of a p-n heterojunction structure. The shorten charge transfer path and the spontaneous formation of p-n heterojunction endow the photocatalyst with efficient spatial separation of photogenerated electrons and holes. As a result, TiO 2 accumulates electrons for efficient hydrogen generation while NiO collects holes to selectively oxidize glycerol into value-added chemicals. The results showed that by loading 5% nickel into the heterojunction caused a remarkable rise in the generation of hydrogen (H 2). The combination of NiO-TiO 2 created 4000 µmolh−1g−1 of H 2 , which is 50% greater than the H 2 production from pure nanosheet TiO 2 and 63 times more than the H 2 production from commercial nanopowder TiO 2. Then, by changing loading amount of Ni, it is found that when 7.5 % of Ni is loaded the highest amount of hydrogen production achieved, 8000 µmolh−1g−1. By employing best sample (S3), 20 % of glycerol converted to value added products, glyceraldehyde and dihydroxyacetone. The feasibility study revealed that glyceraldehyde generates the largest portion of yearly earnings at 89%, while dihydroxyacetone and H 2 account for 11% and 0.03% of the annual revenue, respectively. This work provides a good example to simultaneously produce green hydrogen and valuable chemicals with the rational design of dually functional photocatalyst. [ABSTRACT FROM AUTHOR]

The 3DOM TiO 2 -Au-CdS inverse opal photonic crystal structure is designed for visible-light hydrogen production, exhibiting extremely enhanced photocatalytic activity via coupling bifunctional SPR effect and electron transfer of Au NPs with slow photon effect. [Display omitted] • The ternary TiO 2 -Au-CdS (TAC) photocatalysts have been designed to couple the bifunctional Au NPs with slow photon effect. • A two electron transfer paths model is proposed in the ternary TAC photocatalysts. • Finite-difference time-domain (FDTD) simulations are used to reveal the size effect of Au NPs. • The ternary TAC-10 photocatalyst with ~ 10 nm Au NPs demonstrates the highest hydrogen evolution rate under visible-light. Gold nanoparticles (Au NPs) with surface plasmonic resonance (SPR) effect and excellent internal electron transfer ability have widely been combined with semiconductors for photocatalysis. However, the in-depth effects of Au NPs in multicomponent photocatalysts have not been completely understood. Herein, ternary titanium oxide-gold-cadmium sulfide (TiO 2 -Au-CdS, TAC) photocatalysts, based on hierarchical TiO 2 inverse opal photonic crystal structure with different Au NPs sizes have been designed to reveal the SPR effect and internal electron transfer of Au NPs in the presence of slow photon effect. It appears that the SPR effect and internal electron transfer ability of Au NPs, depending on their sizes, play a synergistic effect on the photocatalytic enhancement. The ternary TAC-10 photocatalyst with ~ 10 nm Au NPs demonstrates an unprecedented hydrogen evolution rate of 47.6 mmolh-1g−1 under visible-light, demonstrating ~ 48% enhancement comparing to the sample without slow photon effect. In particular, a 9.83% apparent quantum yield under 450 nm monochromatic light is achieved for TAC-10. A model is proposed and finite-difference time-domain (FDTD) simulations reveal the size influence of Au NPs in ternary TAC photocatalysts. This work suggests that the rational design of bifunctional Au NPs coupling with slow photon effect could largely promote hydrogen production from visible-light driven water splitting. [ABSTRACT FROM AUTHOR]

• n -p heterojunction of TiO 2 -NiO ultrafine core-shell nanoparticles are prepared. • Strong interfacial interaction significantly improve charge separation efficiency. • As-fabricated photocatalyst exhibits excellent H 2 production from water splitting. • H 2 , CH 4 and fatty acids are cogenerated from biomass lignin photoreforming. Hydrogen evolution from biomass photoreforming has been widely recognized as a promising strategy for relieving the pressure from energy crisis and environmental pollution, as it could generate sustainable H 2 and value-added bioproducts simultaneously. Combining p-type semiconductors with n -type semiconductors to form n -p heterojunction is an effective strategy to improve the photocatalytic quantum efficiency by enhancing the separation of photogenerated electrons and holes, which could greatly facilitate the realization of such biomass photorefinery concept. However, the incompact contact between the n -type and p-type semiconductors often induces the aggregation of photogenerated electrons and holes. In this work, we design and synthesize an ultrafine n -p heterojunction TiO 2 -NiO core-shell structure to overcome the incompact contact in the n -p interface. When the n -p heterojunction photocatalysts are evaluated for photocatalytic water splitting and biomass lignin photoreforming respectively, the as-fabricated TiO 2 -NiO nanocomposite with 3.25% NiO demonstrates the highest hydrogen generation of 23.5 mmol h−1 g−1 from water splitting and H 2 (0.45 mmol h−1 g−1) and CH 4 (0.03 mmol h−1 g−1) cogeneration with reasonable amount of fatty acids (palmitic acid and stearic acid) production from lignin photoreforming. The excellent photocatalytic activity is ascribed to the synergistic effects of high crystallinity of TiO 2 ultrafine nanoparticles, core-shell structure and n -p heterojunction with NiO nanoclusters. This present work demonstrates a simple and efficient method to fabricate ultrafine n -p heterojunction core-shell structure for noble-metal free catalyst for both water splitting and biomass photoreforming. [ABSTRACT FROM AUTHOR]

[Display omitted] Photorefining of biomass is increasingly recognized as a pivotal technology for the simultaneous production of hydrogen and value-added chemicals. The intrinsic recalcitrance of lignocellulosic biomass puts high demands on the rational design of bifunctional photocatalyst. Herein, Ni 2 P/CdS with a strong interfacial effect in this work was designed to overcome lignocellulosic biomass photorefining. The strong interfacial effect between Ni 2 P and CdS not only improved the light absorbance, but also optimized the spatial redistribution of photogenerated electrons and holes. Therefore, Ni 2 P/CdS exhibited an unprecedented H 2 evolution activity (ca. 199.7 mmol·h−1·g−1) in the presence of lactic acid as the traditional sacrificial agent. Considerable H 2 generation was also achieved in the presence of lignin (ca. 322.8 μmol·h−1·g−1), cellulose (ca. 534.3 μmol·h−1·g−1) and hemicellulose (ca. 382.2 μmol·h−1·g−1) as the electron donor respectively. Theoretical calculation results indicated that establishing the interfacial effect between Ni 2 P and CdS optimized their work functions. This optimization fosters improved the redistribution between electrons and holes, as a result, photocatalytic hydrogen production from biomass solution was greatly enhanced. Significantly, Ni 2 P/CdS showed dual functionalities to produce H 2 and value-added compounds from raw biomass directly. This present work demonstrates the potential of raw biomass photorefining through astutely designing photocatalysts. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Novel ternary ZnO/BiVO 4 /3DOM TiO 2 nanocomposites are synthesized. • Ternary ZnO/BiVO 4 /3DOM TiO 2 nanocomposites exhibit enhanced catalytic activity. • The cascade electronic band structure in ternary nanocomposites leads to the enhanced photocatalytic performance. • Coupling semiconductors with suitable energy levels is favorable to improve the efficiency of induced light. Abstract Ternary zinc oxide/bismuth vanadate/three-dimensional ordered macroporous titanium dioxide (ZnO/BiVO 4 /3DOM TiO 2) heterojuncted nanocomposites with cascade electronic band structures were successfully designed and synthesized for visible light photodegradation of two different molecules: Rhodamine B (RhB) and Tartrazine. The photocatalytic active species have been investigated by using electron scavenger (AgNO 3) and hole scavenger (Triethanolamine: TEOA). The band edge positions of each component in tenary nanocomposites have been measured by using photoelectrochemical Mott-Schottky method and valence band XPS (VB-XPS) spectroscopy. Within the heterojunction, charges are favorably and spatially separated through the gradient potential at the interfaces. This largely suppresses the recombination of photogenerated electrons and holes. Furthermore, 3DOM inverse opal structure is beneficial for high diffusion efficiency and highly accessible surface area of reactants and light and multiple scattering for light harvesting. Consequently, these heterojuncted nanocomposites exhibit highly enhanced photocatalytic performance compared with pure BiVO 4 nanostructure, and binary BiVO 4 /3DOM TiO 2 , ZnO/BiVO 4 nanocomposites. A detailed mechanism of charge transfer is proposed for these ternary ZnO/BiVO 4 /3DOM TiO 2 nanocomposites on the basis of a large series of spectroscopic and photocatalytic results. Our work demonstrates clearly that coupling multicomponent semiconductors with different energy levels of conduction and valence bands can significantly increase the photogenerated charge carriers through the efficient charge separation across their multiple interfaces. This work gives some new ideas on developing new visible light responsive nanocomposites for highly efficient solar energy utilization. [ABSTRACT FROM AUTHOR]

Lead is a toxic heavy metal that is highly harmful to humans. Developing fast, efficient, and separable materials to treat lead-contaminated wastewater is challenging. In this paper, Cu-based MOF composite (SCC-CuMOF) was prepared by in-situ growth method and used for the removal of Pb2+ from aqueous solutions. The obtained materials were characterized by field emission scanning electron microscope (FESEM), energy dispersive spectroscopy (EDS) mapping, Brunauer-Emmett-Teller (BET) specific surface area, X-ray diffraction (XRD) and infrared spectroscopy (IR). The effects of pH, coexisting ions, contact time, initial ion concentration, and temperature on the removal of Pb2+ were investigated. SCC-CuMOF exhibited excellent adsorption performance on Pb2+. Adsorption of Pb2+ on SCC-CuMOF were in accordance with the pseudo-second-order model and Langmuir model. The adsorption thermodynamic study suggested that the adsorption process was spontaneous and endothermic. The results revealed that Pb2+ might be adsorbed onto SCC-CuMOF via ion exchange and coordination interaction. In general, SCC-CuMOF has the potential to remove Pb2+ from wastewater rapidly and efficiently. The study prepared SCC-CuMOF composites by in situ growth of Cu-based MOF on the hydrogel SCC-Cu surface for the removal of Pb2+ from aqueous solutions. [Display omitted] • Cu-based MOF composite (SCC-CuMOF) was prepared by in-situ growth method. • SCC-CuMOF exhibited excellent adsorption performance on Pb2+. • The maximum adsorption capacity for Pb2+ was 531.38 ​mg/g at 308 ​K. • The mechanism of Pb2+ adsorption on composites is thoroughly discussed. [ABSTRACT FROM AUTHOR]

Abstract: Texton dictionary-based texture representation approaches have been proven to be effective for texture classification. We propose two types of local descriptors based on Gaussian derivatives filters, both of them have the property of continuous rotation invariance. The first descriptor directly uses the maximum of the filter responses named continuous maximum responses (CMR). The second descriptor rectifies the filter responses to calculate principal curvatures (PC) of the image surface. The texton dictionary is learned from the training images by clustering the local descriptors, and the representation of each image is the frequency histogram of the textons. The classification results compared with some other popular methods on the CUReT, KTH-TIPS and KTH-TIPS2-a datasets show that representation based on CMR achieves best classification result on the CUReT dataset. The representation based on PC achieves the best classification results on the KTH-TIPS and KTH-TIPS2-a datasets, and the classification performance is robust on different datasets. The experiments of rotation invariant analysis implemented on the Brodatz album illustrate that the CMR descriptor has good inter-class distinguish ability and PC descriptor has strong intra-class congregate ability. The results demonstrate that the proposed local descriptors achieve remarkable performance to classify the rotated textures. [Copyright &y& Elsevier]

[Display omitted] • Glucose conversion assisted photocatalytic water splitting technology avoid the use of sacrificial agents while realizing co-product of H 2 and high value-added chemicals. • Both hierarchical 3DOM structure and type Ⅱ heterojunction are conducive to the absorption and utilization of light and the separation and transmission of carriers. • The 3DOM CTO-ZCS photocatalyst simultaneously has high photocatalytic H 2 production performance (2.81 mmol g-1h−1) and high glucose conversion (85.57 %). • The conversion of glucose to lactic acid is a two-step reaction and the control reaction step is gluconic acid to lactic acid. Glucose conversion assisted photocatalytic water splitting technology to simultaneously produce H 2 and high value-added chemicals is a promising method for alleviating the energy shortage and environmental crisis. In this work, we constructing type II heterojunction by in-situ coupling Zn 0.3 Cd 0.7 S quantum dots (ZCS QDs) on three-dimensionally ordered microporous CaTiO 3 (3DOM CTO) for photocatalytic H 2 production and glucose conversion. The DFT calculations demonstrate that substitution of Zn on the Cd site improves the separation and transmission of photogenerated carriers. Therefore, 3DOM CTO-ZCS composite exhibits best H 2 production performance (2.81 mmol g-1h−1) and highest apparent quantum efficiency (AQY) (5.56 %) at 365 nm, which are about 47 and 18 times that of CTO nanoparticles (NPs). The improved catalytic performance ascribed to not only good mass diffusion and exchange, highly efficient light harvesting of 3DOM structure, but also the efficient charges separation of type Ⅱ heterojunction. The investigation on photocatalytic mechanism indicates that the glucose is mainly converted to gluconic acid and lactic acid, and the control reaction step is gluconic acid to lactic acid. The selectivity for gluconic acid on 3DOM CTO-ZCS is 85.65 %. Our work here proposes a green sustainable method to achieve highly efficient H 2 production and selective conversion of glucose to gluconic acid. [ABSTRACT FROM AUTHOR]

We report three types of conducting polymers (CPs), polyaniline (PANI), polypyrrole (PPY) and poly (3,4-ethylenedioxythiophene) (PEDOT) to modify the surface of the CdS nanorods to probe their photocorrosion inhibition and photocatalytic hydrogen production. Various characterizations, such as high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV) and density function theory (DFT) calculations have been conducted to reveal the intrinsic structure of the as-constructed CPs@CdS (@ means CPs at the surface of CdS) core-shell nanorods. The results show that the PANI and PPY shells with abundant N and C atoms can significantly enhance the binding energy of Cd and S atoms on the surface of the CdS nanorods. However, there is no obvious enhancement of binding energy at the interface of the PEDOT shell and the CdS nanorods core. Therefore, PANI@CdS and PPY@CdS possess stronger driving force than PEDOT@CdS to inject the photogenerated holes in conducting polymer shells. As a result, the polyaniline (PANI) modified PANI@CdS core-shell nanorods demonstrate the most effectively enhanced hydrogen production rate of ∼9.7 mmol h −1  g −1 and effective photocorrosion inhibition in 30 h without deactivation under visible-light irradiation. The hydrogen production performance of PPY@CdS is not effectively promoted owing to the weak transmittance of light for the PPY shell. The PEDOT shell cannot improve the hydrogen production and stability property of the CdS nanorods. This work could shed some light on conducting polymers modifying metal sulfides nanostructures that is of inconceivable significance for effective photocorrosion inhibition and highly enhanced photocatalytic activities. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Ni clusters accelerate the separation and transmission of the photogenerated electrons and holes. • The in-situ photoluminescence measurement confirms the Ni clusters as more active sites for hydrogen production. • The Ni/ZnIn 2 S 4 composites demonstrate remarkable hydrogen production rate. • The Ni/ZnIn 2 S 4 composites exhibit good stability and reusability. As a typical two-dimensional (2D) metal chalcogenides and visible-light responsive semiconductor, zinc indium sulfide (ZnIn 2 S 4) has attracted much attention in photocatalysis. However, the high recombination rate of photogenerated electrons and holes seriously limits its performance for hydrogen production. In this work, we report in-situ photodeposition of Ni clusters in hierarchical ZnIn 2 S 4 nanoflowers (Ni/ZnIn 2 S 4) to achieve unprecedented photocatalytic hydrogen production. The Ni clusters not only provide plenty of active sites for reactions as evidenced by in-situ photoluminescence measurement, but also effectively accelerate the separation and migration of the photogenerated electrons and holes in ZnIn 2 S 4. Consequently, the Ni/ZnIn 2 S 4 composites exhibit good stability and reusability with highly enhanced visible-light hydrogen production. In particular, the best Ni/ZnIn 2 S 4 photocatalyst exhibits an unprecedented hydrogen production rate of 22.2 mmol·h−1·g−1, 10.6 times that of the pure ZnIn 2 S 4 (2.1 mmol·h−1·g−1). And its apparent quantum yield (AQY) is as high as 56.14% under 450 nm monochromatic light. Our work here suggests that depositing non-precious Ni clusters in ZnIn 2 S 4 is quite promising for the potential practical photocatalysis in solar energy conversion. [ABSTRACT FROM AUTHOR]

Lactate is a glycolysis end product, and its levels are markedly associated with disease severity, morbidity, and mortality in sepsis. It modulates key functions of immune cells, including macrophages. In this investigation, transcriptomic analysis was performed using lactic acid, sodium lactate, and hydrochloric acid-stimulated mouse bone marrow-derived macrophages (iBMDM), respectively, to identify lactate-associated signaling pathways. After 24 h of stimulation, 896 differentially expressed genes (DEG) indicated were up-regulation, whereas 792 were down-regulated in the lactic acid group, in the sodium lactate group, 128 DEG were up-regulated, and 41 were down-regulated, and in the hydrochloric acid group, 499 DEG were up-regulated, and 285 were down-regulated. Subsequently, clinical samples were used to further verify the eight genes with significant differences, among which Tssk6, Ypel4, Elovl3, Trp53inp1, and Cfp were differentially expressed in patients with high lactic acid, indicating their possible involvement in lactic acid-induced inflammation and various physiological diseases caused by sepsis. However, elongation of very long chain fatty acids protein 3 (Elovl3) was negatively correlated with lactic acid content in patients. The results of this study provide a necessary reference for better understanding the transcriptomic changes caused by lactic acid and explain the potential role of high lactic acid in the regulation of macrophages in sepsis. • Transcriptomic analysis of iBMDM stimulated with lactic acid, sodium lactate, and hydrochloric acid. • TSSK6, YPEL4, ELOVL3, TRP53INP1, and CFP were highly expressed in septic patients with hyperlactic acid. • Elovl3 was negatively correlated with lactic acid content in patients with sepsis. [ABSTRACT FROM AUTHOR]

The well-designed Cu 2 O hollow nanospheres with active {1 1 0} and {1 1 1} facets can quickly remove the pollutants from water. We report the well-designed active {1 1 0} and {1 1 1} faceted Cu 2 O hollow nanospheres (Cu 2 O-HNs) for the quick removal of the high concentration pollutants in water. For the first time, these Cu 2 O-HNs combine the advantages of the active facets, hollow structure and nanostructures. The abundance of dangling Cu atoms in two active facets results in positively charged surface to effectively react with the negatively charged pollutants. The hollow structure provides the opportunity to take full use of these active sites. Consequently, the active faceted Cu 2 O-HNs demonstrate excellent adsorption and photodegradation capacities for high concentrated anionic dyes. The smallest Cu 2 O-HNs (~100 nm) can adsorb ~90% of methyl blue (MB) (100 mg L−1) in 10 min and degrade ~92% of MB (100 mg L−1) in 10 min under visible-light. In particular, a film consisting of the smallest Cu 2 O-HNs can quickly remove high concentrated organic dyes and be reused after solar light irradiation for 10 min in air, showing the promising practical application for the removal of organic pollutants. [ABSTRACT FROM AUTHOR]

This manuscript investigated the catalytic performance of toluene over Ce-Mn-O x catalysts synthesized by four different routes. Ce-Mn-O x prepared by HT method showed superior catalytic activity of toluene due to its more structural defects, oxygen vacancies, surface adsorption oxygen and other active species. Ce-Mn-O x catalysts were synthesized by impregnation (CM-IM), co-precipitation (CM-CP), citrate sol-gel (CM-SG) and hydrothermal (CM-HT) methods. The synthesis methods exhibited a great impact on the physicochemical properties of catalysts, resulting in different catalytic activity. The catalytic oxidation activity of toluene followed the sequence: CM-HT (T 50 : 234 °C; T 90 : 246 °C) > CM-SG (T 50 : 242 °C; T 90 : 249 °C) > CM-CP (T 50 : 243 °C; T 90 : 259 °C) > CM-IM (T 50 : 251 °C; T 90 : 261 °C), which was consistent with the sequence of surface relative percentage of C ov , Ce3+, Mn3+, O α and r values. Among them, CM-HT showed the best catalytic oxidation performance of toluene due to more structural defects, oxygen vacancies, surface adsorption oxygen, normalized conversion rate and other active species. In addition, CM-HT catalysts showed reliable water resistance and good durability, implying the potential industrial application. [ABSTRACT FROM AUTHOR]

MoS 2 quantum dots (QDs) in-situ directing porous MoS 2 -QDs/ZnIn 2 S 4 heterostructures exhibit the H 2 production rate under visible light. Photocatalytic hydrogen (H 2) production based on semiconductors is important to utilize solar light for clean energy and environment. Herein, we report a visible light responsive heterostructure, designed and constructed by molybdenum disulfide quantum dots (MoS 2 -QDs) in-situ seeds-directing growth and self-assemble of zinc indium sulfide (ZnIn 2 S 4) nanosheet to ensure their full contact through a simple one-step solvothermal method for highly improved visible light H 2 production. The MoS 2 -QDs in-situ seeds-directing ZnIn 2 S 4 heterostructure not only builds heterojunctions between MoS 2 and ZnIn 2 S 4 to spatially separate the photogenerated electrons and holes, but also serves as the active sites trapping photogenerated electrons to facilitate H 2 evolution. As a result, MoS 2 -QDs/ZnIn 2 S 4 exhibits high photocatalytic activity for H 2 production, and the optimized 2 wt% MoS 2 -QDs/ZnIn 2 S 4 (2MoS 2 -QDs/ZnIn 2 S 4) heterostructure exhibits the highest H 2 evolution rate of 7152 umol·h−1·g−1 under visible light, ∼9 times of pure ZnIn 2 S 4. Our strategy here could shed some lights on developing noble-metal free heterostructures for highly efficient photocatalytic H 2 production. [ABSTRACT FROM AUTHOR]

Graphical abstract Hierarchically porous ZnO/g-C 3 N 4 microspheres with type-II heterojunction exhibit an enhanced photocatalytic degradation on rhodamine B and phenol. Abstract Graphitic carbon nitride (g-C 3 N 4) is a visible light active semiconductor. However, low conductivity and high recombination rate of photogenerated electrons and holes limit its application in photocatalysis. In this work, we design and synthesize hierarchically porous zinc oxide/graphitic carbon nitride (ZnO/g-C 3 N 4) microspheres with type-II heterojunction to effectively degrade rhodamine B (RhB) via increasing the charge-separation efficiency. The ultraviolet-visible (UV–Vis) absorption spectra, Mott-Schottky plots and valence band X-ray photoelectron spectroscope confirm the formation of type-II heterojunction between ZnO nanocrystals and g-C 3 N 4 nanosheets. As a result, the 1.5-ZnO/g-C 3 N 4 composite (the mass ratio of zinc acetate dihydrate to g-C 3 N 4 is 1.5) exhibits the highest photocatalytic activity with good stability and higher photocatalytic degradation rate comparing to pure g-C 3 N 4 and pure ZnO. In addition, our results confirm that O 2 − and h+ are the main active species for ZnO/g-C 3 N 4 in degradation of RhB. [ABSTRACT FROM AUTHOR]

Abstract: In this study, we identify a recombinant pb1 gene, a recombinant MP segment and a recombinant PA segment. The pb1 gene is recombined from two Eurasia swine H1N1 influenza virus lineages. It belongs to a H1N1 swine clade circulating in Europe and Asia from 1999 to 2009. The mosaic MP segment descends from H7 avian and H1N1 human virus lineages and pertains to a large human H1N1 virus family circulating in Asia, Europe and America from 1918 to 2007. The recombinant PA segment originated from two swine H1N1 lineages is found in a swine H1N1 group prevailing in Asia and Europe from 1999 to 2003. These results collectively falsify the hypothesis that influenza virus do not evolve by homologous recombination. Since recombination not only leads to virus genome diversity but also can alter its host adaptation and pathogenecity; the genetic mechanism should not be neglected in influenza virus surveillance. [Copyright &y& Elsevier]