Optimization of extreme ultraviolet vortex beam based on high harmonic generation

In high harmonic generation(HHG),Laguerre–Gaussian(LG) beams are used to generate extreme ultraviolet(XUV)vortices with well-defined orbital angular momentum(OAM),which have potential applications in fields such as microscopy and spectroscopy.An experimental study on the HHG driven by vortex and Gaussian beams is conducted in this work.It is found that the intensity of vortex harmonics is positively correlated with the laser energy and gas pressure.The structure and intensity distribution of the vortex harmonics exhibit significant dependence on the relative position between the gas jet and the laser focus.The ring-like structures observed in the vortex harmonics,and the interference of quantum paths provide an explanation for the distinct structural characteristics.Moreover,by adjusting the relative position between the jet and laser focus,it is possible to discern the contributions from different quantum paths.The optimization of the HH vortex field is applicable to the XUV,which opens up a new way for exploiting the potential in optical spin or manipulating electrons by using the photon with tunable orbital angular momentum.

Elliptically polarized high-order harmonic generation of Ar atom in an intense laser field

High-order harmonic generation(HHG) of Ar atom in an elliptically polarized intense laser field is experimentally investigated in this work.Interestingly,the anomalous ellipticity dependence on the laser ellipticity(ε) in the lower-order harmonics is observed,specifically in the 13rd-order,which displays a maximal harmonic intensity at ε ≈ 0.1,rather than at ε = 0 as expected.This contradicts the general trend of harmonic yield,which typically decreases with the increase of laser ellipticity.In this study,we attribute this phenomenon to the disruption of the symmetry of the wave function by the Coulomb effect,leading to the generation of a harmonic with high ellipticity.This finding provides valuable insights into the behavior of elliptically polarized harmonics and opens up a potential way for exploring new applications in ultrafast spectroscopy and light–matter interactions.

Minimum structure of high-harmonic spectra from aligned O_(2) and N_(2) molecules

We experimentally investigated the high-order harmonic generation(HHG)from aligned O_(2) and N_(2) molecules in a linearly polarized laser field,and presented the dependence of the harmonic spectrum on the driving laser intensity and molecular alignment angle.The minimum position of HHG of O_(2) varies with changing the laser intensity,which is caused by multi-orbital interference.However,the location of the observed minimum structure in N_(2) harmonic spectrum remained unchanged upon changing the laser intensity.The mechanism of the spectral minimum for N_(2) case is regarded as a Cooperlike minimum in HHG associated with the molecular electronic structure.This work indicates that harmonic spectroscopy can effectively uncover information about molecular structure and electron dynamics.

Identification of core genes and pathways in major depressive disorder by bioinformatic methods

Objective:This study aims to identify key genes and pathways associated with the molecular biological mechanisms of major depressive disorder through bioinformatics analysis in the Gene Expression Omnibus(GEO)public database of the National Center for Biotechnology Information(NCBI)website.Methods:The whole-transcriptome brain expression profile dataset(GSE101521)was obtained from the GEO database.Differentially-expressed genes(DEGs)in normal group(non-psychiatric human)and MDD group(depressive patients)were identified applying Networkanalyst online database.Gene ontology(GO)analysis and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analysis were performed to function annotation and enrichment analysis.After that,STRING online database was conducted to protein-protein interaction(PPI)network,and Cytoscape.3.7.2 software was performed to module analysis.Results:Out of the 41 DEGs identified from normal tissue samples and MDD,39 were upregulated and 2 were downregulated.GO enrichment analysis discovered that DEGs were primarily involved in inflammatory response,and KEGG pathway analysis suggested that the most chiefly pathway related to MDD were IL-17 signaling pathway,TNF signaling pathway and NOD-like receptor signaling pathway.Six hub genes(IL6,CXCL8,IL1B,FOS,CCL2 and CXCL2)were identified by PPI network and module analysis.Conclusion:Our current study detected novel markers and targets involved immune system,which are involved in pivotal biological mechanisms related to the pathogenesis of major depression.Looking forward,these findings still need to be validated in future experimental studies.

Atmospheric chemistry of 2-nitrobenzaldehyde:Initiated by photo-excitation,OH-oxidation,and small TiO_(2) clusters adsorption catalysis

The fate of 2-nitrobenzaldehyde(2-NBA)is of interest in atmospheric chemistry as it is a semi-volatile organic compound with high photosensitivity.This study presents a quantum chemical study of the gas-phase reactions of 2-NBA photo-excitation and OH-oxidation in the absence and presence of small TiO_(2) clusters.To further understand the unknown photolysis mechanism,the photo-reaction pathways of ground singlet state and the lying excited triplet state of 2-NBA were investigated including the initial and subsequent reactions of proton transfer,direct CO,NO_(2),and HCO elimination routes in the presence of O_(2) and NO.Meanwhile,the OH-mediated degradation of 2-NBA proceeded via five H-extraction and six OH-addition channels by indirect mechanism,which follows a succession of reaction steps initiated by the formation of weakly stable intermediate complexes.The H-extraction from the-CHO group was the dominant pathway with a negative activation energy of-1.22 kcal/mol.The calculated rate coefficients at 200–600 K were close to the experimental data in literature within 308-352 K,and the kinetic negative temperature independence was found in both experimental literature and computational results.Interestingly,2-NBA was favored to be captured onto small TiO_(2) clusters via six adsorption configurations formed via various combination of three types of bonds of Ti…O,Ti…C,and O…H between the molecularly adsorbed 2-NBA and TiO_(2) clusters.Comparison indicted that the chemisorptions of aldehyde oxygen have largest energies.The results suggested adsorption conformations have a respectable impact on the catalysis barrier.This study is significant for understanding the atmospheric chemistry of 2-nitrobenzaldehyde.

Examining ecosystem(dis-)services on liver fluke infection in rural Northeast Thailand

Background The direct reliance of humans on and their interactions with freshwater ecosystems in the Lower Mekong Basin have given rise to parasitic infections,which is particularly prevalent in Northeast Thailand where raw fish consumption is practiced.This study examined the interactions between environments,ecosystem(dis-)services,human raw fish consumption habits,and raw fish dish sharing on liver fluke infection risk.Method Water fecal contents and the first intermediate snail host were sampled between June and September of 2019.One hundred twenty questionnaires were surveyed in two villages of different environmental surroundings,one next to a river and the other located inland,in Northeast Thailand.Multivariate regression analyses using linear mixed effect models assessed the influence of social,behavioral and perceptual factors on raw fish consumption frequency,willingness to avoid consumption and liver fluke infection status.Social network analysis compared the degree of raw fish dish sharing between the villages and assessed the probable influence of connections to fish procurement locations and sharing activities on liver fluke infection risk.Results High abundance of the first intermediate snail host and presence of fecal contamination in water could endanger both villages to ecosystem disservices of parasitic transmission.The river-side village relied more on provisioning ecosystem services than the inland village(29.7%vs.16.1%of villages)to consume raw fish as their main source of protein.Males in both villages(64.5 and 40.4 days/year for the respective villages)are also likely to consume koi pla and pla som,higher risk fish dishes,more frequently than females(4.1 and 4.3 days/year for the respective villages).The consumption habits of both villages were driven mostly by deriving cultural ecosystem services.Participation in raw fish dish sharing activities significantly reduced the odds of an individual being willing to avoid the consumption(Odds ratio=0.19).Network analysis suggested that river-side villagers had a more direct raw fish dish sharing interaction and they procured fish from multiple locations;these characteristics might potentially account for more liver fluke infected households in the village.Conclusion Villagers’raw fish consumption is driven by deriving cultural ecosystem services,and the geographic settings of the villages potentially affect villagers’fish procurement locations and infection risk.The findings underscore the linkages between villagers and their surrounding ecosystem environments as pertinent determinants for foodborne parasitic disease risk.

Superficial angiomyxoma of penis： a case report of a 6-year follow-up

Dear Editor, We report a case of an 18-year-old Chinese man with two recurring asymptomatic superficial angiomyxomas on his penis. After an incisional biopsy, we resected the masses on the proximal and distal ends of the penis.