Toward the Rational Design of Galactosylated Glycoclusters That Target Pseudomonas aeruginosa Lectin A (LecA): Influence of Linker Arms That Lead to Low‐Nanomolar Multivalent Ligands

Anti‐infectious strategies against pathogen infections can be achieved through antiadhesive strategies by using multivalent ligands of bacterial virulence factors. LecA and LecB are lectins of Pseudomonas aeruginosa implicated in biofilm formation. A series of 27 LecA‐targeting glycoclusters have been synthesized. Nine aromatic galactose aglycons were investigated with three different linker arms that connect the central mannopyranoside core. A low‐nanomolar (K_d=19 nm , microarray) ligand with a tyrosine‐based linker arm could be identified in a structure–activity relationship study. Molecular modeling of the glycoclusters bound to the lectin tetramer was also used to rationalize the binding properties observed.     

Scheme for implementing quantum dense coding with four-particle decoherence-free states in an ion trap

This paper proposes an experimentally feasible scheme for implementing quantum dense coding of trapped-ion system in decoherence-free states. As the phase changes due to time evolution of components with different eigenenergies of quantum superposition are completely frozen, quantum dense coding based on this model would be perfect. The scheme is insensitive to heating of vibrational mode and Bell states can be exactly distinguished via detecting the ionic state.     

Optimal intracellular calcium signaling

In many cell types, calcium is released from internal stores through calcium release channels upon external stimulation (e.g., pressure or receptor binding). These channels are clustered with a typical cluster size of about 20 channels, generating stochastic calcium puffs. We find that the clustering of the release channels in small clusters increases the sensitivity of the calcium response, allowing for coherent calcium responses at signals to which homogeneously distributed channels would not respond.     

Singlet-triplet splitting of geminate electron-hole pairs in conjugated polymers

The singlet-triplet splitting of geminate polaron pairs in a ladder-type conjugated polymer has been studied by the thermally stimulated luminescence technique. The energy gap separating the singlet and triplet states of the geminate pairs is measured to be in the range of 3-6 meV, depending on the polymer morphology. The results of correlated quantum-chemical calculations on a long ladder-type oligomer are fully consistent with the observed values of the geminate polaron pair singlet-triplet gap. Such low splitting values have important implications for the spin-dependent exciton formation in conjugated polymers.     

Optical properties of singly charged conjugated oligomers: a coupled-cluster equation of motion study

We have implemented a coupled-cluster equation of motion approach combined with the intermediate neglect of differential overlap parametrization and applied it to study the excited states and optical absorptions in positively and negatively charged conjugated oligomers. The method is found to be both reliable and efficient. The theoretical results are in very good agreement with experiments and confirm that there appear two subgap absorption peaks upon polaron formation. Interestingly, the relative intensities of the polaron-induced subgap absorptions can be related to the extent of the lattice geometry relaxations.     

全光纤激光相干合成光谱响应特性研究

基于N-腔镜谐振腔理论对全光纤激光相干合成进行了理论分析，数值模拟了迈克尔逊型相干合成激光器的光谱特性，对两个光纤Bragg光栅的中心波长差和两路光的光程差对合成光谱特性的影响给出了理论解释.用啁啾光纤光栅取代其中一个光纤Bragg光栅，使激光相干合成的带宽由0.3 nm拓展到1.0 nm.     

Collimation testing using a circular Dammann grating

A novel technique for collimation testing with a circular Dammann grating is proposed. When the beam under test is incident on a one-order circular Dammann grating with limited aperture, double-humped radial rings will be generated at the back focal plane of a focusing lens. If the beam is collimated, the separation between the two rings will reach its minimal, otherwise the two rings will be apart from each other. Therefore, the degree of collimation of the tested beam can be estimated from the separation. The principle and experimental results of the method are presented. Owing to the simplicity and low cost of the method, it is a promising method for quickly checking the collimation of a laser beam.     

Negative Refraction and Near-Field Imaging of an Elliptical-Rod Photonic Crystal Slab in the Second Band

Negative refraction and imaging properties of the electromagnetic wave through a two-dimensional photonic crystal （PC） slab, which consists of a square lattice of elliptical dielectric rods immersed in the air background, is studied by the plane-wave expansion method and the finite-difference time-domain method. A point source placed in the vicinity of the PC slab can form a good-quality image spot through the PC slab for the incident frequencies within the second photonic band. The calculated result also shows that negative refraction occurs in this kind of PC slab.     

Transmission Properties of W3 Y-Branch Filters in Two-Dimensional Photonic Crystal Slabs

A highly efficient W3 Y-branch filter in a two-dimensional photonic crystal slab with triangular lattice of air holes is designed and fabricated, and its transmission properties are measured. By accurately adjusting the size of the resonant cavities, the minimum wavelength spacing of 7 nm between two channels is realized. The corresponding resonant wavelengths of the two cavities agree well with the calculated ones. This implies that this kind of fiIter may be promising in integrated wavelength division multiplexing system.     

UV Photodissociation Dynamics of Nitric Acid： The Hydroxyl Elimination Channel

Sliced velocity mapping ion imaging technique was employed to investigate the dynamics of the hydroxyl elimination channel in the photodissociaiton of nitric acid in the ultraviolet region. The OH product was detected by （2＋1） resonance enhanced multiphoton ionization via the D^2∑^- electronic state. The total kinetic energy spectra of the OH＋NO2 channel from the photolysis of HONO2 show that both ：NO2（X2A1） and NO2（A2B2） channels are present, suggesting that both 1^1A″ and 2^1A″ excited electronic states of HONO2 are involved in the excitation. The parallel angular distributions suggest that the dissociation of the nitric acid is a fast process in comparison with the rotational period of the HNO3 molecule. The anisotropy parameter β for the hydroxyl elimination channel is found to be dependent on the OH product rotational state as well as the photolysis energy.