Measurement of the coupling constant in a two-frequency VECSEL

We measure the coupling constant between the two perpendicularly polarized eigenstates of a two-frequency Vertical External Cavity Surface Emitting Laser (VECSEL). This measurement is performed for different values of the transverse spatial separation between the two perpendicularly polarized modes. The consequences of these measurements on the two-frequency operation of such class-A semiconductor lasers are discussed.

Differential Signaling by ErbB Receptor (HER) Dimers: Implications for Response to Anti-HER2 Therapies in Breast Cancer

The ErbB family of receptor tyrosine kinases comprises of EGFR, HER2, HER3 and HER4. Ligand binding induces receptor homo- and heterodimerization and activation of downstream signaling. No ligand(s) have been identified for HER2. Recruitment of HER2 to ligand-activated co-receptors potentiates signaling by HER2-containing heterodimers. To identify differential signaling induced by HER2/HER3 and HER2/EGFR heterodimers and HER2 homodimers, we developed a cell system where HER2 dimerization can be conditionally regulated. A retroviral vector encoding HA-tagged full-length human HER2 fused to ligand-binding domain of FK506 binding protein (FKBP) in the C-terminus was stably transduced into MCF10A mammary epithelial cells. Treatment of MCF10A-HER2-FKBP-HA cells with the intracellular dimerizer AP1510 resulted in homodimerization and tyrosine phosphorylation of the HER2 chimera. The EGFR ligands EGF and TGFα and the HER3 ligand heregulin induced HER2/EGFR and HER2/HER3 heterodimers. Microarray analysis with RNA isolated from vehicle, AP1510, TGFα and heregulin treated cells identified unique transcriptional activities associated with HER2/HER2, HER2/HER3 and HER2/EGFR induced signaling. Ingenuity Pathway analysis of the microarray data showed that HER2 homodimers had the most significant effect on the “G2/M DNA damage checkpoint regulation pathway” whereas HER2/EGFR dimers had the most pronounced effect on the “pyrimidine metabolism pathway”. Active HER2/HER3 dimers affected the NF-κB signaling pathway the most.To determine if differential signaling by ErbB dimers have any implications for the response to anti-HER2 therapies, we treated MCF10A-HER2-FKBP-HA cells with AP1510, TGFα or heregulin in the presence or absence of trastuzumab, pertuzumab or lapatinib. In 3D Matrigel, AP1510-treated cells formed invasive acini while untreated cells failed to grow. EGF and TGFα and heregulin also stimulated acini growth in 3D. The anti-HER2 antibody trastuzumab completely inhibited AP1510-stimulated but not EGF, TGFα, or heregulin-stimulated growth. Lapatinib, a dual inhibitor of the HER2 and EGFR tyrosine kinases, blocked EGF, heregulin, and AP1510-induced growth. Pertuzumab, an antibody that blocks ligand-induced HER2 heterodimerization, inhibited heregulin-induced but not AP1510-induced growth. Reverse Phase Protein Array performed with lysates from cells treated with AP1510, TGFα or heregulin indicated that AP1510 failed to activate S473 p-AKT. This is a key enzyme in the PI3K pathway, which has been associated with resistance to HER2 inhbitors. Western blot analyses showed that AP1510 induced p-ERK whereas TGFα and Heregulin activated p-AKT. Binding assays with 125I-labeled trastuzumab indicated that treatment with AP1510 enhanced binding of trastuzumab compared to untreated cells. This result suggests that HER2 homodimers present a conformation to which trastuzumab binds better. Taken together, these data suggest that 1) because of their inability to activate Akt, cells dependent on HER2-containing homodimers are less able to bypass trastuzumab action; and 2) high levels of HER2 homodimers in breast cancers with HER2 gene amplification may represent a biomarker predictive of response to trastuzumab.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 705.

Observation of electromagnetically induced transparency and slow light in the dark state--bright state basis

The quantum coherence phenomenon of electromagnetically induced transparency (EIT) is observed in a three-level system composed of an excited state and two coherent superpositions of the two ground-state levels. This peculiar ground state basis is composed of the so-called bright and dark states of the same atomic system in a standard coherent population trapping configuration. The characteristics of EIT, namely, width of the transmission window and reduced group velocity of light, in this unusual basis, are theoretically and experimentally investigated and are shown to be essentially identical to those of standard EIT in the same system.

Multi-loop networked process control: a synchronized approach

Modern day process control uses digital controllers which are based on the principle of distributed rather than centralized control. Distributing controllers, sensors and actuators across a plant entails considerable wiring which can be reduced substantially by integrating the components of a control loop over a network. The other advantages include greater flexibility and higher reliability with lower hardware redundancy. The controllers and sensors are on a network and can take over the function of a failed component automatically, without the need of manual reconfiguration, thus eliminating the need of having a redundant component for each and every component. Though elaborate techniques have been developed for Single Input Single Output (SISO) systems, the major challenge lies in extending these ideas to control a practical process plant where de-centralized control is actually achieved through control of individual SISO control loops derived through de-coupling of the original system. Multiple loops increase network load and hence the sampling times associated with the control loops and makes synchronization difficult. This paper presents a methodology by which network based process control can be applied to practical process plants, with a simple direct synchronization mechanism.

Investigations and control measures following a case of inhalation anthrax in East London in a drum maker and drummer, October 2008

The patient is believed to have acquired the infection from making animal hide drums. Environmental investigations identified one drum and two pieces of animal skins contaminated with anthrax spores.

Investigations and control measures following a case of inhalation anthrax in East London in a drum maker and drummer, October 2008

We discuss the investigations and control measures undertaken following the notification of a fatal case of inhalation anthrax in East London. The patient is believed to have acquired the infection from making animal hide drums. Environmental investigations identified one drum and two pieces of animal skins contaminated with anthrax spores.

Antiinflammatory activity of a polyherbal formulation

The antiinflammatory activity of the polyherbal formulation Entox(®) was investigated in rats for acute and sub acute models of inflammation using carrageenan-induced rat paw edema and cotton pellet granuloma methods respectively at a dose of 300 mg/kg and 600 mg/kg administered orally. The formulation in doses of 300 mg/kg and 600 mg/kg showed 51.61% and 54.84% inhibition of paw edema, respectively at the end of 3 h. The percent inhibition of granuloma by cotton pellet method was 27.92% and 53.17%, respectively. The formulation showed a significant antiinflammatory activity in both the experimental models and the activity was comparable to that of the standard drug, indomethacin.

Gene therapy as a novel therapeutic option in the treatment of peripheral vascular disease: systematic review and meta-analysis

BACKGROUND

Stimulation of therapeutic angiogenesis using gene therapy is a novel intervention for peripheral vascular disease (PVD). Despite encouraging outcomes from animal studies and phase 1 trials, results from larger trials in this area have been conflicting. We undertook a systematic review and meta-analysis of randomised controlled trials in this field, to clarify the current situation.

METHODS

Medline, Embase, trial registries, the American Heart Association (AHA) abstract database and article reference lists were searched to identify randomised controlled trials of gene therapy for treatment of PVD. The outcomes were change in peak walking time and claudication onset time at 90 and 180 days post-treatment, and change in ankle-brachial pressure index (ABPI) at 90 days. Weighted mean differences (WMD) were calculated for these outcomes.

RESULTS

Five eligible randomised clinical trials were identified, containing 508 patients. There were no significant differences between control and intervention groups for any outcomes, irrespective of whether low-dose or high-dose gene therapy was tried.

CONCLUSION

The available data suggests that gene therapy confers no benefit on patients with PVD. Closer examination of the individual trials shows that several have an excessive placebo response, which may go some way to explaining our result. Further research in this area in needed.

Molecular characterization and sequence variability of betasatellites associated with leaf curl disease of kenaf (hibiscus cannabinus L.) from different geographical locations of India

Leaf curl disease of kenaf (Hibiscus cannabinus L.) in India has been found to be associated with begomoviruses and betasatellites. Here, we report the molecular characterization and phylogenetic relationship of the nine isolates of betasatellites obtained from three geographical locations in India. The betasatellites coming from northern and eastern region of India shared 84.3% nucleotide sequence identity and formed two sub-clusters within the main cluster containing different isolates of Cotton leaf curl Multan betasatellite (CLCuMB) isolated in Indian subcontinent. Betasatellites coming from the southern part of India were identified as the isolates of Tomato leaf curl Joydebpur betasatellite and shared 45.2 and 44.9% sequences identity with their counterparts coming from the eastern and northern India, respectively. The present study represents the first report about the association of the leaf curl disease of kenaf with the betasatellites infecting both malvaceous and non-malvaceous crops in India.

EDXRF analysis of municipal solid waste using 109Cd source

Elemental compositions of municipal solid waste (MSW) samples have been analyzed using the non-destructive energy dispersive X-ray fluorescence (EDXRF) technique. The samples were collected from three different dumping sites of urban and suburban areas of the city of Kolkata, West Bengal, India. The EDXRF spectrometer consisted of a (109)Cd radioactive source and a Si (Li) detector. To check the reliability of the system, NIST Standard Reference Material-1648 UPM had been analyzed and it was found that within the experimental errors, our results agree quite well with the certified and non-certified values. The elemental compositions of all the three MSW samples were subsequently estimated using the same procedure. The matrix effects were estimated following the emission-transmission method. It was observed that except Fe, all the elements from Ti to Pb show concentration levels higher by a factor of 2-7 than the ecological screening values where as in the case of Fe, this factor varies from 100 to 200.

A study on multivariable process control using message passing across embedded controllers

Multivariable process control forms an important part of modern day control. While hardwired controllers still constitute the basic component of such control systems, with reducing communication latencies, controllers on the network are being mooted as a viable alternative. These controllers promise a large number of advantages in terms of reduction in wiring and greater flexibility in implementing supervisory control systems. In this paper, a study is presented which shows that UDP (User Datagram Protocol) can actually be used for real-time multivariable process control. Latency reduction algorithms used in high performance message passing systems have been used.

Deregulation and cross talk among Sonic hedgehog, Wnt, Hox and Notch signaling in chronic myeloid leukemia progression

Deciphering the BCR-ABL-independent signaling exploited in chronic myeloid leukemia (CML) progression is an important aspect in cancer stem-cell biology. CML stem-cell compartment is dynamic as it progresses to terminal blast crisis where myeloid and lymphoid blasts fail to differentiate. We demonstrate cross-regulation of signaling network involving Sonic hedgehog (Shh), Wnt, Notch and Hox for the inexorable blastic transformation of CD34(+) CML cells. Significant upregulation in Patched1, Frizzled2, Lef1, CyclinD1, p21 (P < or =0.0002) and downregulation of HoxA10 and HoxB4 (P< or =0.0001) transcripts in CD34(+) cells distinguish blast crisis from chronic CML. We report Shh-dependent Stat3 activation orchestrates these mutually interconnected signaling pathways. Stimulation of CD34(+) CML cells with either soluble Shh or Wnt3a did not activate Akt or p44/42-mitogen activated protein kinase (MAPK) pathways. Interestingly, unlike dominant negative Stat3beta, introduction of constitutive active Stat3 in CD34(+) CML cells induces cross-regulation in gene expression. Additionally, Shh and Wnt3a-dependent regulation of cyclin-dependent kinase inhibitors (CDKI) in CML suggests their role in the network. Taken together, our findings propose that deregulation in the form of hyperactive Shh and Wnt with repressed Notch and Hox pathways involving Stat3, Gli3, beta-catenin, CyclinD1, Hes1, HoxA10 and p21 might act synergistically to form an important hub in CML progression.

Symbolic reachable set computation of piecewise affine hybrid automata and its application to biological modelling: Delta-Notch protein signalling

Hybrid automata are an eminently suitable modelling framework for biological protein regulatory networks, as the protein concentration dynamics inside each biological cell are modelled using linear differential equations; inputs activate or deactivate these continuous dynamics through discrete switches, which themselves are controlled by protein concentrations reaching given thresholds. This paper proposes an iterative refinement algorithm for computing discrete abstractions of a class of hybrid automata with piecewise affine continuous dynamics and forced discrete transitions, defined completely in terms of symbolic variables and parameters. Furthermore, these discrete abstractions are utilised to compute symbolic parametric backward reachable sets from the equilibria of the hybrid automata, that are guaranteed to be exact or conservative under-approximations. The algorithm is then implemented using MATLAB and QEPCAD, to compute reachable sets for the biologically observed equilibria of the multiple cell Delta-Notch protein signalling automaton with symbolic parameters. The results are analysed to show that novel, non-intuitive, and biologically interesting properties can be deduced from the reachability computation, thus demonstrating the utility of the algorithm.

Spread of cholera with newer clones of Vibrio cholerae O1 El Tor, serotype inaba, in India

During 2004 and 2005, cholera was recorded in 15 states of India, with 7 outbreaks. The newly emerged Vibrio cholerae O1 Inaba had a different antibiogram and ribotype, different pulsotypes, and different mutations in the wbeT gene. Due to the absence of serogroup O139, the Inaba serotype may have acquired the potential to affect the population at large.