Parameter Mismatches and Perfect Anticipating Synchronization in bi-directionally coupled external cavity laser diodes

We study perfect chaos synchronization between two bi-directionally coupled external cavity semiconductor lasers and demonstrate for the first time that mismatches in laser photon decay rates can explain the experimentally observed anticipating time in synchronization.Comment: Latex 4 page

Assessment of oceanic tuna and allied fish resources of the Indian exclusive economic zone based on exploratory surveys

The present paper overview the results of survey on marine resources of the Indian EEZ including tuna and eillied fish species, their distribution, catch rates, seasonality, assessment of stocks etc. supplemented by the chartered vessels' data. The paper also presents the trends in the tuna fishing and future survey programme of the Fishery Survey of India

Factors which influence the cardiac surgeon's decision not to operate on patients referred for consideration of surgery

<p>Abstract</p> <p>Background</p> <p>The aim of this study was to document what proportion of patients referred for consideration of cardiac surgery are turned down, the reasons given for not operating and also to evaluate what happens to those patients who do not undergo surgery.</p> <p>Methods</p> <p>382 elective patients referred for consideration of cardiac surgery to one of six consultant cardiac surgeons at Wythenshawe Hospital during a one year period from were included in the study. Data for those patients who underwent an operation were collected prospectively in a cardiac surgery database. The case notes of those patients who did not undergo an operation were reviewed to establish reasons given by surgeons for not operating. Patients were followed up to determine vital status at the end of the study period.</p> <p>Results</p> <p>333 (87.2%) patients underwent an operation and 49 (12.8%) did not. 68% of patients turned down were thought to be too high-risk. 14% of patients did not fulfill symptomatic or prognostic criteria for surgery and in 8% of patients coronary artery surgery was thought ineffective due to poor distal vessels. 6% of patients declined an operation and 4% were thought to be more suitable for coronary angioplasty. Patients turned down for surgery had more renal dysfunction (p = 0.017), respiratory disease (p < 0.001) and peripheral vascular disease (p < 0.001), were more likely to have undergone prior heart surgery (p < 0.001) and to have poor left ventricular function (p = 0.003). Patients turned down for surgery had significantly higher EuroSCORE values compared to patients who underwent an operation: 5 versus 4 (p = 0.006). Freedom from death in the patients turned down for surgery at 1-, 6-, 12- and 24-months was 95.9%, 91.8%, 83.7% and 71.4% respectively, compared with 97.9%, 96.7%, 96.4% and 94.5% for the patients who underwent an operation (p < 0.001 [log-rank]). 14 of the 15 deaths that occurred in the turned down group occurred in the category considered too high-risk for surgery.</p> <p>Conclusion</p> <p>12.8% of patients referred for consideration of cardiac surgery did not undergo an operation. Two thirds of patients not accepted for surgery were thought too high risk. Those patients who did not undergo an operation had a significantly worse mortality.</p

Systems design of a high resolution retinal prosthesis

Simulations of artificial vision suggest that 1000 electrodes may be required to restore vision to individuals with diseases of the outer retina. In order to achieve such an implant, new technology is needed, since the state-of-the-art implantable neural stimulator has at most 22 contacts with neural tissue. Considerable progress has been made towards that goal with the development of image processing, microelectronics, and polymer based MEMS. An image processing system has been realized that is capable of real-time implementation of image decimation and filtering (for example, edge detection). Application specific integrated circuits (ASICs) have been designed and tested to demonstrate closed loop power control and efficient microstimulation. A novel packaging process has been developed that is capable of simultaneously forming communication coils, interconnects, and stimulating electrodes

Pancreatic Lipase inhibition assay of various extracts of leaves of Murraya Koenigii in southern areas of Goa

The objective of the study was to assess the lipase inhibitory activities of chloroformic, methanolic and aqueous extracts from the commonly available Murraya koenigii (L.) Spreng leaves(Rutaceae) in southern villages of Goa, for potential use in the treatment of obesity. Extracs of the leaves of this plant were evaluated for lipase inhibitory activity using porcine pancreatic lipase (PPL: triacylglycerol lipase) and p-nitrophenyl butyrate in an in vitro assay. Among the three extracts screened, chloroformic extract exhibited the highest pancreatic lipase inhibitory activity of 53.42%, followed by methanolic extract (51.88%) and aqueous extract (36.42%), respectively. Chloroformic extract has not been screened for its pancreatic lipase inhibition assay. All the Crude extracts of leaves of Murraya koenigii (L.) Spreng leaves (Rutaceae) have potential as pancreatic lipase inhibitory agents. . Chloroformic extract was found to be most effective and hence can be used as a potent anti-obesity agent to combat hyperlipidemia

Spatiotemporal communication with synchronized optical chaos

We propose a model system that allows communication of spatiotemporal information using an optical chaotic carrier waveform. The system is based on broad-area nonlinear optical ring cavities, which exhibit spatiotemporal chaos in a wide parameter range. Message recovery is possible through chaotic synchronization between transmitter and receiver. Numerical simulations demonstrate the feasibility of the proposed scheme, and the benefit of the parallelism of information transfer with optical wavefronts.Comment: 4 pages, 5 figure

2-Arylamino-6-ethynylpurines are cysteine-targeting irreversible inhibitors of Nek2 kinase

Renewed interest in covalent inhibitors of enzymes implicated in disease states has afforded several agents targeted at protein kinases of relevance to cancers. We now report the design, synthesis and biological evaluation of 6-ethynylpurines that act as covalent inhibitors of Nek2 by capturing a cysteine residue (Cys22) close to the catalytic domain of this protein kinase. Examination of the crystal structure of the non-covalent inhibitor 3-((6-cyclohexylmethoxy-7H-purin-2-yl)amino)benzamide in complex with Nek2 indicated that replacing the alkoxy with an ethynyl group places the terminus of the alkyne close to Cys22 and in a position compatible with the stereoelectronic requirements of a Michael addition. A series of 6-ethynylpurines was prepared and a structure activity relationship (SAR) established for inhibition of Nek2. 6-Ethynyl-N-phenyl-7H-purin-2-amine [IC50 0.15 μM (Nek2)] and 4-((6-ethynyl-7H-purin-2-yl)amino)benzenesulfonamide (IC50 0.14 μM) were selected for determination of the mode of inhibition of Nek2, which was shown to be time-dependent, not reversed by addition of ATP and negated by site directed mutagenesis of Cys22 to alanine. Replacement of the ethynyl group by ethyl or cyano abrogated activity. Variation of substituents on the N-phenyl moiety for 6-ethynylpurines gave further SAR data for Nek2 inhibition. The data showed little correlation of activity with the nature of the substituent, indicating that after sufficient initial competitive binding to Nek2 subsequent covalent modification of Cys22 occurs in all cases. A typical activity profile was that for 2-(3-((6-ethynyl-9H-purin-2-yl)amino)phenyl)acetamide [IC50 0.06 μM (Nek2); GI50 (SKBR3) 2.2 μM] which exhibited >5–10-fold selectivity for Nek2 over other kinases; it also showed > 50% growth inhibition at 10 μM concentration against selected breast and leukaemia cell lines. X-ray crystallographic analysis confirmed that binding of the compound to the Nek2 ATP-binding site resulted in covalent modification of Cys22. Further studies confirmed that 2-(3-((6-ethynyl-9H-purin-2-yl)amino)phenyl)acetamide has the attributes of a drug-like compound with good aqueous solubility, no inhibition of hERG at 25 μM and a good stability profile in human liver microsomes. It is concluded that 6-ethynylpurines are promising agents for cancer treatment by virtue of their selective inhibition of Nek2

Structure-guided design of purine-based probes for selective Nek2 inhibition

Nek2 (NIMA-related kinase 2) is a cell cycle-dependent serine/threonine protein kinase that regulates centrosome separation at the onset of mitosis. Overexpression of Nek2 is common in human cancers and suppression can restrict tumor cell growth and promote apoptosis. Nek2 inhibition with small molecules, therefore, offers the prospect of a new therapy for cancer. To achieve this goal, a better understanding of the requirements for selective-inhibition of Nek2 is required. 6-Alkoxypurines were identified as ATP-competitive inhibitors of Nek2 and CDK2. Comparison with CDK2-inhibitor structures indicated that judicious modification of the 6-alkoxy and 2-arylamino substituents could achieve discrimination between Nek2 and CDK2. In this study, a library of 6-cyclohexylmethoxy-2-arylaminopurines bearing carboxamide, sulfonamide and urea substituents on the 2-arylamino ring was synthesized. Few of these compounds were selective for Nek2 over CDK2, with the best result being obtained for 3-((6-(cyclohexylmethoxy)-9H-purin-2-yl)amino)-N,N-dimethylbenzamide (CDK2 IC50 = 7.0 μM; Nek2 IC50 = 0.62 μM) with >10-fold selectivity. Deletion of the 6-substituent abrogated activity against both Nek2 and CDK2. Nine compounds containing an (E)-dialkylaminovinyl substituent at C-6, all showed selectivity for Nek2, e.g. (E)-6-(2-(azepan-1-yl)vinyl)-N-phenyl-9H-purin-2-amine (CDK2 IC50 = 2.70 μM; Nek2 IC50 = 0.27 μM). Structural biology of selected compounds enabled a partial rationalization of the observed structure activity relationships and mechanism of Nek2 activation. This showed that carboxamide 11 is the first reported inhibitor of Nek2 in the DFG-in conformation

Physics and Applications of Laser Diode Chaos

An overview of chaos in laser diodes is provided which surveys experimental achievements in the area and explains the theory behind the phenomenon. The fundamental physics underpinning this behaviour and also the opportunities for harnessing laser diode chaos for potential applications are discussed. The availability and ease of operation of laser diodes, in a wide range of configurations, make them a convenient test-bed for exploring basic aspects of nonlinear and chaotic dynamics. It also makes them attractive for practical tasks, such as chaos-based secure communications and random number generation. Avenues for future research and development of chaotic laser diodes are also identified.Comment: Published in Nature Photonic

Systems design of a high resolution retinal prosthesis

Simulations of artificial vision suggest that 1000 electrodes may be required to restore vision to individuals with diseases of the outer retina. In order to achieve such an implant, new technology is needed, since the state-of-the-art implantable neural stimulator has at most 22 contacts with neural tissue. Considerable progress has been made towards that goal with the development of image processing, microelectronics, and polymer based MEMS. An image processing system has been realized that is capable of real-time implementation of image decimation and filtering (for example, edge detection). Application specific integrated circuits (ASICs) have been designed and tested to demonstrate closed loop power control and efficient microstimulation. A novel packaging process has been developed that is capable of simultaneously forming communication coils, interconnects, and stimulating electrodes