Sample preparation for mass spectrometry imaging of leaf tissues: a case study on analyte delocalization

Analytical and Bioanalytical Chemistry - Appropriate sample preparation is pivotally important to obtain high-quality mass spectrometry imaging (MSI) data. Unlike mammalian tissues, preparation of...     

Route to hyperchaos and chimera states in a network of modified Hindmarsh-Rose neuron model with electromagnetic flux and external excitation

Analyzing the chaos and bursting phenomenon of neurons has been of interest in the past decade. In this paper, we discuss an extended Hindmarsh-Rose neuron model by taking into consideration the slowly interacting cell phenomenon due to the calcium ions. In the extended model, we consider the effect of an external forcing current, and the electromagnetic coupling between the magnetic flux and the membrane potential of the neuron. We analyze the modified neuron model in the presence of periodic and quasi-periodic excitations. A more complex chaotic behavior (hyperchaos) is identified in the neuron model. The results also demonstrate the multistable nature, which was not explored earlier. To discuss the dynamical behavior of the modified neuron in a network, we construct a ring network of neurons and capture the spatiotemporal patterns of the neuron in the network, in the presence of different excitations.

     

EXPERIMENTAL RESEARCH ON FAILURE AND ENERGY DISSIPATION CHRACTERISTICS OF THE SANDSTONE1)

通过三轴卸荷试验,探究了不同路径下卸荷速率对砂岩力学特性及破坏过程中的能量耗散的影响。试验结果表明在全过程应力-应变曲线的弹性阶段,轴向变形起主导作用,弹塑性阶段,环向应变的增加值大于轴向应变增加值。在围压卸荷阶段,卸荷速率越小,卸荷阶段的应变折合柔度越大,此时岩样的变形不充分,呈现明显的脆性破坏。恒主应力差路径下的耗散能大于恒轴压路径下的耗散能的35%,卸荷速率越大,岩样的弹性应变能越小。     

Chaos synchronization and encoding in coupled semiconductor lasers of multiple modulated time delays

We numerically investigate the synchronization performance of unidirectionally and bidirectionally coupled chaotic semiconductor lasers subject to multiple modulated time delays optical feedbacks. Moreover, by studying the autocorrelation function of the coherent feedback semiconductor laser output, we find that the signatures of time delays can be erased in systems incorporating modulated feedback time delays, which largely improve the system security. Finally, chaos masking switching (CMS) is utilized to examine the communication ability. Numerical results indicate that the messages could be successfully recovered both in unidirectionally and bidirectionally coupled lasers, which confirms the possibility of applying multiple modulated delay system in optical chaos secure communication.     

Novel electrochemical biosensor based on functional composite nanofibers for sensitive detection of p53 tumor suppressor gene

A novel electrochemical biosensor based on functional composite nanofibers for sensitive hybridization detection of p53 tumor suppressor using methylene blue (MB) as an electrochemical indicator is developed. The carboxylated multi-walled carbon nanotubes (MWNTs) doped nylon 6 (PA6) composite nanofibers (MWNTs–PA6) was prepared using electrospinning, which served as the nanosized backbone for pyrrole (Py) electropolymerization. The functional composite nanofibers (MWNTs–PA6–PPy) used as supporting scaffolds for ssDNA immobilization can dramatically increase the amount of DNA attachment and the hybridization sensitivity. The biosensor displayed good sensitivity and specificity. The target wild type p53 sequence (wtp53) can be detected as low as 50 fM and the discrimination is up to 57.5% between the wtp53 and the mutant type p53 sequence (mtp53). It holds promise for the early diagnosis of cancer development and monitoring of patient therapy.     

灯泵浦激光器输出激光稳定性实验研究

分析了灯泵浦激光器的特点以及影响其输出激光稳定性的原因,提出了在激光器谐振腔内加一个“Q开关”的方法来控制输出激光的稳定性,以氙灯泵浦的被动锁模Nd:YAG激光器为例进行了实验研究,证实了此方案是可行的.     

A scheme for teleporting Schrdinger-cat states via the dispersive atom-cavity-field interaction

A proposal is presented for teleporting Schrding-cat states. The process of the teleportation is achieved through the dispersive atom-cavity-field interaction. In this proposal, only measurement on the cavity field and on the singlet atomic states are used.     

Structure–Property Relationship of Sulfosuccinic Acid Diester Sodium Salt Micelles: 3D-QSAR Model and DPD Simulation

The objective of this study was to develop structure–property relationship of a series of sulfosuccinic acid diester sodium salts required for industrial purposes. In this paper, three-dimensional quantum structure–activity relationship (3D-QSAR) method studies are performed to elucidate the relationship between critical micelle concentration (CMC) activity and molecular 3D structural features. Two regression models are developed by partial least squares (PLS) and genetic function approximation (GFA), respectively. The training set of PLS-QSAR model generates a correlation coefficient (R²) = 0.94539300 and sum of square of residues (S²) = 0.32764200. For the GFA-QSAR model, the training set yields R² = 1.00000000. It is shown that the GAF method effectively improves the test accuracy significantly. Dissipative particle dynamics (DPD) mesoscopic molecular simulation method is carried out on the aggregation behavior of polyoxyethylene (n) stearyl ether sodium sulfosuccinate (PSSE-n) surfactant micelles. In the DPD simulation, water molecular (solvent) and colloidal particles are replaced by a set of DPD particles. The results demonstrated that sensitive PSSE-n molecules can assemble into special structures in specific solution concentration, such as star-shaped micelle, spherical micelle, rodlike micelle, and lamellar phase. DPD simulation can be used as an efficient method for studying the structure–property relationship of sulfosuccinic acid diester sodium salts.     

真空紫外/可见光纳秒条纹相机的研制

ZNT-500K真空紫外/可见光纳秒条纹相机已研制成功,在研制过程中,研制了新型变象管,较好地解决了MgF²晶体和科伐材料的高真空封接,合理地确定了导电基底的材料和厚度,使光谱响应和透过率都满足要求;合理地确定扫描电路和电路参数,使该相机具有了光谱响应范围宽和扫描时间范围宽两大特点。     

Direct determination of the electron-phonon coupling matrix element in a correlated system

High-resolution electron energy loss spectroscopy measurements have been carried out on an optimally doped cuprate Bi(2)Sr(2)CaCu(2)O(8+δ). The momentum-dependent energy and linewidth of an A1 optical phonon were obtained. Based on these data as well as detailed knowledge of the electronic structure, we developed a scheme to determine the electron-phonon coupling (EPC) matrix element related to a specific phonon mode. Such an approach is general and applicable to elucidating the full structure of EPC in a system with anisotropic electronic structure.