842 research outputs found
Quantitative analysis of multi-spectral fundus images
We have developed a new technique for extracting histological parameters from multi-spectral images of the ocular fundus. The new method uses a Monte Carlo simulation of the reflectance of the fundus to model how the spectral reflectance of the tissue varies with differing tissue histology. The model is parameterised by the concentrations of the five main absorbers found in the fundus: retinal haemoglobins, choroidal haemoglobins, choroidal melanin, RPE melanin and macular pigment. These parameters are shown to give rise to distinct variations in the tissue colouration. We use the results of the Monte Carlo simulations to construct an inverse model which maps tissue colouration onto the model parameters. This allows the concentration and distribution of the five main absorbers to be determined from suitable multi-spectral images. We propose the use of "image quotients" to allow this information to be extracted from uncalibrated image data. The filters used to acquire the images are selected to ensure a one-to-one mapping between model parameters and image quotients. To recover five model parameters uniquely, images must be acquired in six distinct spectral bands. Theoretical investigations suggest that retinal haemoglobins and macular pigment can be recovered with RMS errors of less than 10%. We present parametric maps showing the variation of these parameters across the posterior pole of the fundus. The results are in agreement with known tissue histology for normal healthy subjects. We also present an early result which suggests that, with further development, the technique could be used to successfully detect retinal haemorrhages
Designing Robust Unitary Gates: Application to Concatenated Composite Pulse
We propose a simple formalism to design unitary gates robust against given
systematic errors. This formalism generalizes our previous observation [Y.
Kondo and M. Bando, J. Phys. Soc. Jpn. 80, 054002 (2011)] that vanishing
dynamical phase in some composite gates is essential to suppress amplitude
errors. By employing our formalism, we naturally derive a new composite unitary
gate which can be seen as a concatenation of two known composite unitary
operations. The obtained unitary gate has high fidelity over a wider range of
the error strengths compared to existing composite gates.Comment: 7 pages, 4 figures. Major revision: improved presentation in Sec. 3,
references and appendix adde
Isolation, identification and anti-cancer activity of minor alkaloids from Triclisia subcordata
No abstrac
A Report on the Environmental Impact of the Texas LoanSTAR Program from May 1989 to September 1995
There are a number of factors that influence emission factors. The three major pollutants considered in this analysis are CO2, SO2, and NOX. Emission factors from three different sources were considered for this report. This analysis shows that as of September, 1995, there has been a reduction in emissions of 1.88 million pounds of NOX, 1.19 million pounds of SO2, and 532 million pounds of CO2 through the implementation of energy conservation measures in the Texas LoanSTAR program.The Texas LoanSTAR (Loans to Save Taxes and Resources) program was created by the state of Texas in 1989 to lend money for energy conserving improvements, or retrofits, in public buildings. As of September 1995 the LoanSTAR program is measuring savings for 22 loan sites covering 153 buildings where retrofits have been fully or partially completed. The completed retrofits show $21.1 million in measured savings, which is more than 119% of the energy savings predicted by the energy auditors. This corresponds to 23.9% of the pre-retrofit consumption cost at these sites. Through energy savings, the Texas LoanSTAR program has made a significant contribution towards reducing hazardous environmental emissions
Systemic lupus erythematosus and diffuse alveolar hemorrhage, etiology and novel treatment strategies.
Diffuse alveolar hemorrhage is a severe respiratory complication of systemic lupus erythematosus. The illness develops over hours to a few days and is the systemic lupus erythematosus-associated syndrome with highest mortality. Although no specific symptoms have been identified, a number of features are associated with diffuse alveolar hemorrhage, with a drop in blood hemoglobin the most prominent. Dyspnea, blood-stained sputum, diffuse infiltrates identified by chest imaging, elevated single breath-diffusing capacity for monoxide, thrombocytopenia and C3 hypocomplementemia are other commonly reported signs of diffuse alveolar hemorrhage. The etiology is not completely understood but many patients develop diffuse alveolar hemorrhage concomitant with lupus nephritis, suggesting immune complex-driven pathology. Biopsy studies have identified both cases with capillaritis and a bland non-inflammatory phenotype. An animal model of diffuse alveolar hemorrhage has indicated requirement of B lymphocytes and complement receptor-mediated apoptotic body phagocytosis by monocytes as part of the pathogenesis. This review will discuss considerations when diagnosing the condition and available therapies. Infections and other causes of hemorrhage have to be excluded as these require different treatment strategies. Methylprednisolone and cyclophosphamide remain the most commonly used therapies. Plasmapheresis and rituximab are other beneficial treatment options. A few studies have also considered intrapulmonary Factor VII therapy, extracorporeal membrane oxygenation and mesenchymal stem cell therapy. There is an unmet need of better definition of diffuse alveolar hemorrhages etiology and pathology for development of improved treatment strategies
An exploratory study of information sources and key findings on UK cocaine-related deaths.
Cocaine-related deaths have increased since the early 1990s in Europe, including the UK. Being multi-factorial, they are difficult to define, detect and record. The European Monitoring Centre for Drugs and Drug Addiction commissioned research to: describe trends reported to Special Mortality Registries and General Mortality Registers; provide demographic and drug-use characteristic information of cases; and establish how deaths are identified and classified. A questionnaire was developed and piloted amongst all European Monitoring Centre for Drugs and Drug Addiction Focal Point experts/Special Mortality Registries: 19 (63%) responded; nine countries provided aggregated data. UK General Mortality Registers use cause of death and toxicology to identify cocaine-related deaths. Categorisation is based on International Classification of Diseases codes. Special Mortality Registries use toxicology, autopsy, evidence and cause of death. The cocaine metabolites commonly screened for are: benzoylecgonine, ecgonine methyl ester, cocaethylene and ecgonine. The 2000s saw a generally accelerating upward trend in cases, followed by a decline in 2009. The UK recorded 2700-2900 deaths during 1998-2012. UK Special Mortality Registry data (2005-2009) indicate: 25-44 year-olds account for 74% of deaths; mean age=34 (range 15-81) years; 84% male. Cocaine overdoses account for two-thirds of cases; cocaine alone being mentioned/implicated in 23% in the UK. Opioids are involved in most (58%) cocaine overdose cases
Steam reforming on transition-metal carbides from density-functional theory
A screening study of the steam reforming reaction (CH_4 + H_2O -> CO + 3H_2)
on early transition-metal carbides (TMC's) is performed by means of
density-functional theory calculations. The set of considered surfaces includes
the alpha-Mo_2C(100) surfaces, the low-index (111) and (100) surfaces of TiC,
VC, and delta-MoC, and the oxygenated alpha-Mo_2C(100) and TMC(111) surfaces.
It is found that carbides provide a wide spectrum of reactivities towards the
steam reforming reaction, from too reactive via suitable to too inert. The
reactivity is discussed in terms of the electronic structure of the clean
surfaces. Two surfaces, the delta-MoC(100) and the oxygen passivated
alpha-Mo_2C(100) surfaces, are identified as promising steam reforming
catalysts. These findings suggest that carbides provide a playground for
reactivity tuning, comparable to the one for pure metals.Comment: 6 pages, 4 figure
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