Reconstruction of 3D Image for Particles By the Method of Angular Correlations from XFEL Data

The world’s first X-ray Free Electron Laser (XFEL), the Linac Coherent Light Source (LCLS) at the Stanford Linear Accelerator Center (SLAC), is now generating X-ray pulses of unprecedented brilliance (one billion times brighter than the most powerful existing sources), and at the amazing rate of only a few femtoseconds. The first such experiments are being performed on relatively large objects such as viruses, which produce low resolution, low-noise diffraction patterns on the basis of the so called “diffraction before destruction” principle. Despite the promise of using XFEL for the determination of the structures of viruses, the results so far from experimental data present difficulties in working to reconstruct 3D images for the viruses by our method. One of the rare instances in which images are reconstructed from experimental data is the mimi virus work of Hajdu et al. In this present paper, we examine the capabilities of the method that is based on the angular momentum decomposition of scattered intensities, which enables us to overcome common problems such as missing or imperfect data that are inevitable in experiments. This angular momentum decomposition method helps to avoid the effect of a finite beam size, and existing gap size. In addition to the problem caused by the finite panels of detectors used when the data are collected, the effect of noise, curved Ewald Sphere, shot to shot variations of incident X-ray pulse intensities and shots to multiple nano particles are also studied

Two-dimensional heterogeneous photonic bandedge laser

We proposed and realized a two-dimensional (2D) photonic bandedge laser surrounded by the photonic bandgap. The heterogeneous photonic crystal structure consists of two triangular lattices of the same lattice constant with different air hole radii. The photonic crystal laser was realized by room-temperature optical pumping of air-bridge slabs of InGaAsP quantum wells emitting at 1.55 micrometer. The lasing mode was identified from its spectral positions and polarization directions. A low threshold incident pump power of 0.24mW was achieved. The measured characteristics of the photonic crystal lasers closely agree with the results of real space and Fourier space calculations based on the finite-difference time-domain method.Comment: 14 pages, 4 figure

Robustness of multiparty nonlocality to local decoherence

We investigate the robustness of multiparty nonlocality under local decoherence, acting independently and equally on each subsystems. To be specific, we consider an N-qubit GHZ state under depolarization, dephasing, or dissipation channel, and tested the nonlocality by violation of Mermin-Klyshko inequality, which is one of Bell's inequalities for multi-qubit systems. The results show that the robustness of nonlocality increases with the number of qubits, and that the nonlocality of an N-qubit GHZ state with even N is extremely persistent against dephasing.Comment: 5 pages, 4 figure

Role of PU.1 and C/EBPα in Remodelling the Interleukin (IL)-1β Enhancer-Promoter Interaction

Background: IL-1b is a potent inflammatory cytokine promptly expressed in activated myeloid immune cells. Among various transcription factors, PU.1 and CCAAT/enhancer-binding protein alpha (C/EBPa) play a key role in the lineage commitment of myeloid cells. To date, however, the exact mechanisms by which these lineage-determining transcription factors employ to regulate the expression of myeloid-specific genes remains elusive; thus, this study explores the role of PU.1 and C/EBPa in remodelling the chromatin conformation that allows ample production of IL-1b. Methods: To examine the mechanism of these lineage-determining transcription factors, production of IL-1b and enhancer-promoter interactions were analyzed in non-myeloid B16-BL6 cells that were ectopically expressed with PU.1 and C/EBPa. Results: Overexpression of PU.1 and C/EBPa rendered B16-BL6 cells response to the bacterial component lipopolysaccharide (LPS) and expressed IL-1b. These cells also expressed a putative enhancer RNA, located ~10 kbs upstream of the IL-1b transcription start site, in response to LPS. Knocking out the enhancer region reduced IL-1b mRNA expression, suggesting that the genomic region is an enhancer. Based on the chromatin conformation capture-qPCR analysis, IL-1b enhancer-promoter interactions were established upon overexpression of PU.1 and C/EBPa, which was further enhanced by LPS. Discussion & Conclusion: These results suggest that PU.1 and C/EBPa are pioneering transcription factors that establish chromatin looping between IL-1b regulatory elements and induce the generation of enhancer RNA, resulting in the production of IL-1b in non-myeloid cells. Interdisciplinary Reflection: Our system that investigates how transcription factors can remodel the chromatin landscape will further expand our understanding of gene regulation

Preparation and characterization of spray-dried valsartan-loaded Eudragit® E PO solid dispersion microparticles

AbstractThe purpose of this study was to develop the immediate release stomach-specific spray-dried formulation of valsartan (VAL) using Eudragit® E PO (EPO) as the carrier for enhancing dissolution rate in a gastric environment. Enhanced solubility and dissolution in gastric pH was achieved by formulating the solid dispersion using a spray drying technique. Different combinations of drug–polymer–surfactant were dissolved in 10% ethanol solution and spray-dried in order to obtain solid dispersion microparticles. Use of the VAL–EPO solid dispersion microparticles resulted in significant improvement of the dissolution rate of the drug at pH 1.2 and pH 4.0, compared to the free drug powder and the commercial product. A hard gelatin capsule was filled with the VAL–EPO solid dispersion powder prior to the dissolution test. The increased dissolution of VAL from solid dispersion microparticles in gastric pH was attributed to the effect of EPO and most importantly the transformation of crystalline drugs to amorphous solid dispersion powder, which was clearly shown by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and powder X-ray diffraction (P-XRD) studies. Thus, VAL, a potential antihypertensive drug in the form of a solid dispersion microparticulate powder, can be effectively delivered in the immediate release dosage form for stomach-specific drug delivery

Stability of a Jensen type equation in the space of generalized functions

AbstractWe reformulate and solve the stability problem of a Jensen type functional equation3f(x+y+z3)+f(x)+f(y)+f(z)−2f(x+y2)−2f(y+z2)−2f(z+x2)=0, in the spaces of some generalized functions such as tempered distributions and Fourier hyperfunctions

Configurational force on a dynamic dislocation with localized oscillation

Upon employing the conservation theorem and continuum theory, the configurational force on a singularity, or a defect, is given by a pathindependent integral called the J integral. According to the continuum elasticity theory, the J integral around a steadily moving dislocation is equal to the Peach-Koehler force acting on the dislocation and is independent of the integration path. However, using a discrete lattice dynamics method, we theoretically prove that the J integral is not path-independent in practice even under uniform motion. This is because of the generation of phonons during the dislocation motion. In general, phonons are generated upon localized oscillation of the dislocation, and they dissipate energy from the dislocation core; consequently, a drag force is produced. As the drag force disturbs the dislocation motion, the J integral around the moving dislocation is smaller than that around a stationary one, and its deviation from the stationary one corresponds to the drag force. In this study, we analytically derive the drag force for each oscillation mode by adopting dislocation-phonon coordinates. We classify the oscillation mode simply as symmetric or anti-symmetric after assuming the dislocation to be a localized defect having a finite core width. Consequently, the drag force is numerically calculated upon consideration of the discrete nature of the dislocation core. In particular, our study reveals that the anti-symmetric oscillation mode mainly contributes to the drag force in the limit of high dislocation velocity. Furthermore, we show that the resulting relation between the drag force and dislocation frequency can reproduce the dislocation velocity-stress curve. This work is expected to contribute to mesoand macro-scale plasticity when the material is loaded under extreme conditions or transient dislocation motion can be assumed