Vortex Matter Transition in Bi2{}_2Sr2{}_2CaCu2{}_2O8+y{}_{8+y} under Tilted Fields

Vortex phase diagram under tilted fields from the $c$ axis in Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+y}$ is studied by local magnetization hysteresis measurements using Hall probes. When the field is applied at large angles from the $c$ axis, an anomaly ($H_p^\ast$) other than the well-known peak effect ($H_p$) are found at fields below $H_p$. The angular dependence of the field $H_p^\ast$ is nonmonotonic and clearly different from that of $H_p$ and depends on the oxygen content of the crystal. The results suggest existence of a vortex matter transition under tilted fields. Possible mechanisms of the transition are discussed.Comment: Revtex, 4 pages, some corrections are adde

Modeling the lasing spectra of InAs/InP Quantum dash lasers

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98746/1/ApplPhysLett_98_101105.pd

Investigating The Vortex Melting Phenomenon In BSCCO Crystals Using Magneto-Optical Imaging Technique

Using a novel differential magneto-optical imaging technique we investigate the phenomenon of vortex lattice melting in crystals of Bi_2Sr_2CaCu_2O_8 (BSCCO). The images of melting reveal complex patterns in the formation and evolution of the vortex solid-liquid interface with varying field (H) or temperature (T). We believe that the complex melting patterns are due to a random distribution of material disorder or inhomogeneities across the sample, which create fluctuations in the local melting temperature or field value. To study the fluctuations in the local melting temperature / field, we have constructed maps of the melting landscape T_m(H,r), viz., the melting temperature (T_m) at a given location (r) in the sample at a given field (H). A study of these melting landscapes reveals an unexpected feature: the melting landscape is not fixed, but changes rather dramatically with varying field and temperature along the melting line. It is concluded that the changes in both the scale and shape of the landscape result from the competing contributions of different types of quenched disorder which have opposite effects on the local melting transition.Comment: Paper presented at the International Symposium on Advances in Superconductivity & Magnetism: Materials, Mechanisms & Devices September 25-28, 2001, Mangalore, India. Symposium proceedings will be published in a special issue of Pramana - Journal of Physic

The intestinal virome in children with cystic fibrosis differs from healthy controls.

Intestinal bacterial dysbiosis is evident in children with cystic fibrosis (CF) and intestinal viruses may be contributory, given their influence on bacterial species diversity and biochemical cycles. We performed a prospective, case-control study on children with CF and age and gender matched healthy controls (HC), to investigate the composition and function of intestinal viral communities. Stool samples were enriched for viral DNA and RNA by viral extraction, random amplification and purification before sequencing (Illumina MiSeq). Taxonomic assignment of viruses was performed using Vipie. Functional annotation was performed using Virsorter. Inflammation was measured by calprotectin and M2-pyruvate kinase (M2-PK). Eight CF and eight HC subjects were included (50% male, mean age 6.9 ± 3.0 and 6.4 ± 5.3 years, respectively, p = 0.8). All CF subjects were pancreatic insufficient. Regarding the intestinal virome, no difference in Shannon index between CF and HC was identified. Taxonomy-based beta-diversity (presence-absence Bray-Curtis dissimilarity) was significantly different between CF and HC (R2 = 0.12, p = 0.001). Myoviridae, Faecalibacterium phage FP Taranis and unclassified Gokushovirinae were significantly decreased in CF compared with HC (q<0.05). In children with CF (compared to HC), the relative abundance of genes annotated to (i) a peptidoglycan-binding domain of the peptidoglycan hydrolases (COG3409) was significantly increased (q<0.05) and (ii) capsid protein (F protein) (PF02305.16) was significantly decreased (q<0.05). Picornavirales, Picornaviridae, and Enterovirus were found to positively correlate with weight and BMI (r = 0.84, q = 0.01). Single-stranded DNA viruses negatively correlated with M2-PK (r = -0.86, q = 0.048). Children with CF have an altered intestinal virome compared to well-matched HC, with both taxonomic and predicted functional changes. Further exploration of Faecalibacterium phages, Gokushovirinae and phage lysins are warranted. Intestinal viruses and their functions may have important clinical implications for intestinal inflammation and growth in children with CF, potentially providing novel therapeutic targets

Possible new vortex matter phases in BSCCO

The vortex matter phase diagram of BSCCO crystals is analyzed by investigating vortex penetration through the surface barrier in the presence of a transport current. The strength of the effective surface barrier, its nonlinearity, and asymmetry are used to identify a possible new ordered phase above the first-order transition. This technique also allows sensitive determination of the depinning temperature. The solid phase below the first-order transition is apparently subdivided into two phases by a vertical line extending from the multicritical point.Comment: 11 pages, 3 figures, accepted for publication in PR

SAR Study of Niclosamide Derivatives for Neuroprotective Function in SH-SY5Y Neuroblastoma

Background: Neurodegenerative disease is a debilitating and incurable condition that affects millions of people around the world. The loss of functions or malfunctions of neural cells causes mortality. A proteasome inhibitor, MG132, is well known to cause neurodegeneration in vitro when model neuronal-derived cell lines are exposed to it. Niclosamide, an anthelmintic drug, which has been used for more than 50 years, has recently attracted renewed attention in drug repurposing because it has been found as a good candidate against various diseases in screenings. We recently found that all markers of MG132-induced neuronal cell toxicity, including the accumulation of ubiquitinated proteins, were prevented by niclosamide. In addition, niclosamide was shown to enhance autophagy induced by MG132. Therefore, our results suggest that niclosamide could be a potential neuroprotective agent. In the present study, niclosamide derivatives were synthesized by changing substituents, and their structure-activity relationship (SAR) of the protein ubiquitination induced by MG132 and cell survival signaling pathways for neuroprotective function were studied. Methods: The 12 niclosamide derivatives were synthesized; mostly, they were prepared from the corresponding benzoic acid and aniline derivatives in the presence of PCl3 in dry xylene under reflux conditions. Niclosamide and the 12 derivatives were dissolved in DMSO. The SH-SY5Y cells were cultured at 5% CO2 at 37 °C in EMEM: Ham’s F-12K medium (1:1), 5% horse serum with penicillin (100 units/mL), and streptomycin (100 μg/mL). The cells were sub-cultured weekly in 60 mm or 100 mm cell culture dishes and used for experiments at 85-90% confluence of the cell monolayer. SH-SY5Y cells were treated with niclosamide or derivatives and 5 μM MG132 for 24 h. The cell lysates were prepared for Western blot assays using anti-ubiquitin antibodies, including ubiquitin, PARP, p-JNK, CHOP, cyclin D, and p53. Results: Our results indicate that when phenol OH was present, the compounds demonstrated neuroprotective activity, while the presence or absence of Cl (5- or 2’-Cl) showed almost the same neuroprotective effect. 4’-NO2 can be replaced by N3 or CF3 to have neuroprotective activity, whereas NH2 significantly decreased activity. Yet, when there is no substituent at the 4’- position, there is no significant activity. All the bioassays showed that niclosamide and certain derivatives showed a neuroprotective function. While there is no evidence for the direct bindings of niclosamide and their derivatives to any specific proteins, the results indicate that the phenol OH plays an important role, and chloride at 2’-Cl or 5-Cl, does not affect the neuroprotective activity. 4’-NO2 can be replaced with N3 or CF3. However, 4’-NH2 and 4’-H significantly decreased the neuroprotective function. This suggested the substituent at 4’ position plays some role in bindings. The inhibition of p53 expression by these compounds may have a different mechanism of action, and further investigation will be required in the future. Conclusions: Based on the results of the present study, niclosamide, and its derivatives can be new target molecules for the prevention of Parkinson’s disease (PD) and other neurodegenerative diseases. Also, these findings provide valuable information for the development of the next generation of niclosamide analogs

Biologically Inspired Monocular Vision Based Navigation and Mapping in GPS-Denied Environments

This paper presents an in-depth theoretical study of bio-vision inspired feature extraction and depth perception method integrated with vision-based simultaneous localization and mapping (SLAM). We incorporate the key functions of developed visual cortex in several advanced species, including humans, for depth perception and pattern recognition. Our navigation strategy assumes GPS-denied manmade environment consisting of orthogonal walls, corridors and doors. By exploiting the architectural features of the indoors, we introduce a method for gathering useful landmarks from a monocular camera for SLAM use, with absolute range information without using active ranging sensors. Experimental results show that the system is only limited by the capabilities of the camera and the availability of good corners. The proposed methods are experimentally validated by our self-contained MAV inside a conventional building