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The coronary anomalies are generally asymptomatic and rare. However, their potential complications are serious and mainly represented by the risk of sudden death. The coronarography appears insufficient to carry out the complete assessment of these anomalies, and in particular to study the arterial course. The endpoint of our series is to evaluate the interest of the coronary computed tomography (CT) in this indication.We report the results of a 16-slice coronary-CT monocentric retrospective series among 12 patients presenting coronary anomalies diagnosed in coronarography.Coronary-CT has confirmed the diagnosis, specified the coronary course and the relation with the great vessels in 100% of the cases.Multislice coronary-CT seems an examination of choice for the diagnosis and the presurgical assessment of the coronary aberrations, like for the distinction of the benign and malign forms. Its effectiveness and its "non-invasive" character are strong arguments to include it in the assessment of syncopes linked to effort in the young adult.

Conic mirror reflectometers are used to measure the diffuse reflectance and total integrated scatter of surfaces. In spite of the long history of using conic mirrors for these purposes, the maximum magnification of the three primary types of conic mirror (hemisphere, hemiellipsoid, and dual paraboloid) had not been compared quantitatively. To our knowledge, an exact magnification formula has not been published for any of the three primary conic mirrors. The maximum magnification is needed for proper sizing of detectors and radiation sources used with reflectometers. Exact analytical expressions for the maximum magnification of a Coblentz hemisphere, a hemiellipsoid, and a dual-paraboloid mirror system are derived and compared.

The National Measurement Institutes (NMIs) of the United States, Germany, France, Italy and Japan, have joined in an inter-laboratory comparison of their infrared spectral emittance scales. This action is part of a series of supplementary inter-laboratory comparisons (including thermal conductivity and thermal diffusivity) sponsored by the Consultative Committee on Thermometry (CCT) Task Group on Thermophysical Quantities (TG-ThQ). The objective of this collaborative work is to strengthen the major operative National Measurement Institutes' infrared spectral emittance scales and consequently the consistency of radiative properties measurements carried out worldwide. The comparison has been performed over a spectral range of 2 μm to 14 μm, and a temperature range from 23 °C to 800 °C. Artefacts included in the comparison are potential standards: oxidized Inconel, boron nitride, and silicon carbide. The measurement instrumentation and techniques used for emittance scales are unique for each NMI, including the temperature ranges covered as well as the artefact sizes required. For example, all three common types of spectral instruments are represented: dispersive grating monochromator, Fourier transform and filter-based spectrometers. More than 2000 data points (combinations of material, wavelength and temperature) were compared. Ninety-eight percent (98%) of the data points were in agreement, with differences to weighted mean values less than the expanded uncertainties calculated from the individual NMI uncertainties and uncertainties related to the comparison process. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCT, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Diamond coatings deposited using the low pressure chemical synthesis are benificial on cutting tools, forming dies, and nunches for manufacturing applications; on lenses/mirrors for optical, Laser, IR, and astronomical applications as well as single crystal diamonds grown by this technology for grinding and polishing applications. They offer great potential and can become economically more attractive than diamond grown with the high temperature-high pressure (∼ 1500°C and ∼50 Kbars) synthesis process. The Common technique used for the low pressure synthesis of diamond is the chemical vapor deposition (CVD) activated by hot filament, D.C., R.F., microware etc. with deposition rates of 1-2μm/hr. Recently Hirose of Japan pioncered the combustion synthesis of diamond. Using an oxy-acetylene torch, he able to increase the deposition rate by more than an order or magnitude. This paper presents results or films and single crystal diamonds grown by this technique. Deposition rates of 50 to 100 μm/hr, and single crystals of about 150-200 μm were obtained.

In the literature confusion exists concerning the structure type, the valence of europium, and the amount of nitrogen incorporation of the compound europium aluminum oxynitride. By using X-ray diffraction and luminescence measurements, we show that europium aluminum oxynitride has the magnetoplumbite structure. Eu is present in its divalent state, and a negligible amount of nitrogen is present.

The calibration of infrared (IR) radiometers, thermal imagers and electro-optical systems relies on use of extended area blackbodies (BB) operating in the ambient environment. "Flat plate" designs, typically using a thermoelectric heat pump backed with an air- or liquid-cooled radiator, allow one to adequately meet the requirements of geometrical size and temperature span. The tradeoff comes in the form of limited temperature uniformity and lower emissivity that such an approach can provide given the limitations in achievable thermal conductivity of the plate and reflectance of the black paint, respectively. The availability of spectrally resolved radiance temperature data for infrared calibrators has become especially vital in the last few years with the widespread use of multi- and hyper-spectral electro-optical systems that enable better detection and identification of targets. In an effort to increase the measurement accuracy of IR spectral radiance of near-ambient BB calibrators, NIST has recently built a dedicated capability which is a part of its new AIRI (Advanced Infrared Radiometry and Imaging) facility. The Tunable Filter Comparator (TFC) is a key new element in this setup, allowing us to perform a precise comparison of the unit under test (UUT) with two reference blackbodies of known temperatures and emissivity. The report describes the major design features of the TFC comparator, the algorithm used for signal processing, and results of a performance evaluation of the TFC. The TFC development has enabled us to achieve BB radiance temperature comparisons with a standard deviation of 5 to 15 mK at temperatures of 15-150 C across the 3 to 5 µm and 8 to 12 µm atmospheric band ranges with a relative spectral resolution of 2 to 3%.

Multidetector computed tomography coronarography (MDCT) is a promising tool, offering non invasive anatomic evaluation of coronary arteries. We relate in this article our impressions after our first two years experience.Retrospective study of the 328 patients who underwent MDCT examination between January 2005 and December 2006 at our community hospital. Per patient comparative analysis of the anatomical findings versus percutaneous angiography (PCA) in 61 cases.Out of 328 patients 61 (18.5%) underwent PCA. In these patients we found a sensibility, specificity, positive predictive value and negative predictive value of 100%, 54%, 59% and 100% for MDCT. The main factor responsible for inconclusive vessel analysis was excessive calcification.In routine use, MDCT enables one to rule out significant stenosis non invasively, with high sensitivity in an unselected patient population.

Die Heterogenisierung eines Titan(IV)-Silsesquioxankomplexes in einem MCM-41-Molekularsieb durch Einstellen der Polaritat des MCM-41-Netzwerkes fuhrt zu selbstorganisierten Materialverbanden (Kalottenmodell rechts), die sich als aktive, heterogene und somit wiederverwendbare Katalysatoren fur die Alken-Oxidation in flussiger Phase eignen.

Drug eluting stent is a new technology aimed to prevent the development of neointimal hyperplasia and restenosis following percutaneous coronary intervention. This review describes the direction for their use at the present time and the future of their utilization with the summary of the principals clinicals trials.

The reference spectral power responsivity scale of NIST is being extended from the silicon range to the infrared (IR) using pyroelectric radiometers. Two transfer standard pyroelectric radiometers have been developed at NIST. The main design consideration was to obtain only a minimal increase in the measurement uncertainty during the responsivity scale extension. Domain engineered LiNbO3 and regular LiTaO3 pyroelectric detectors were used in the two radiometers. Both detectors are gold-black coated and temperature controlled. Reflecting domes are attached to the radiometer inputs to decrease the reflectance loss and to improve the spatial uniformity of responsivity in the infrared. Four commercial pyroelectric detectors have been added to the group and used as working standards. The relative spectral responsivity of all pyroelectric detectors was determined from spectral reflectance measurements. The radiant power responsivity tie points were derived from Si trap and single element detectors traceable to the NIST reference responsivity scale. The pyroelectric radiometers have been characterized for frequency and temperature dependent responsivity, noise, spatial non-uniformity of responsivity, angular responsivity, and linearity. The expanded (relative) uncertainty of the spectral power responsivity calibrations ranged between 0.5 % and 1.2 % (k=2) within the 1 μm to 19 μm range.

We summarize recent progress in our infrared (IR) spectral radiance metrology effort. In support of customer blackbody characterization, a realization of the spectral radiance scale has been undertaken in the temperature range of 232 °C to 962 °C and spectral range of 2.5 μm to 20 μm. We discuss the scale realization process that includes the use of Sn, Zn, Al and Ag fixed-point blackbodies (BB), as well as the transfer of the spectral radiance scale to transfer standard BBs based on water, Cs and Na heat pipes. Further we discuss the procedures for customer source calibration with several examples of the spectral radiance and emissivity measurements of secondary standard BB sources. For one of the BBs, a substantial deviation of emissivity values from the manufacturer specifications was found. Further plans include expansion of the adopted methodology for temperatures down to 15 °C and building a dedicated facility for spectral characterization of IR radiation sources.

Realization of a radiometric temperature scale for near ambient temperatures with accuracy at the 20 to 50 mK level is crucial for a number of demanding military and commercial applications. In support of such measurements, radiation sources with high stability and spatial uniformity must be developed as reference and working standards. Traditionally, the temperature scale, maintained at the National Institute of Standards and Technology (NIST), relies on water bath and oil bath blackbodies in this temperature range. Recently, a water heat pipe blackbody was used at NIST as a spectral radiance source in a spectral emissivity measurement facility. Now a new, more versatile high emissivity water heat pipe blackbody was designed and characterized to be used as a reference radiance source for the radiometric temperature scale realization between 50 °C and 250 °C. Furthermore, it will serve as a reference source for the infrared spectral radiance measurements between 2.5 μm and 20 μm. The calculated spectral emissivity of the painted copper alloy cavity was verified by reflectance measurements using a CO2 laser at 10.6 μm wavelength. The spatial thermal uniformity and stability of the blackbody were characterized. Two independent realizations of the radiometric temperature scale were compared in order to verify the accuracy of the scale. Radiance temperature, calculated from the cavity temperature measured with a calibrated PRT contact thermometer and from the emissivity of the cavity, was compared to the radiance temperature, directly measured with a reference pyrometer, which was calibrated with a set of fixed point blackbodies. The difference was found to be within measurement uncertainties.

Use of linear or concentric grooves is a well-known approach for increasing the surface emissivity to enable the construction of compact blackbody radiators, improve absorptance of stray radiation traps, baffles and thermal radiation detectors, as well as enhance thermal radiation transfer. Emitters with V-grooved surfaces are widely used as reference sources in radiation thermometry and radiometry. In the design phase of such devices, it is important to predict their performance. Most existing models are devoted to modeling isothermal linear grooves with purely diffuse or specular reflectance. Radiation behavior of concentric grooves differs from linear ones and becomes similar only for large values of the ratio of the radial coordinate to the groove period. This paper covers numerical modeling of isothermal and nonisothermal concentric grooves with mixed specular-diffuse reflection for various viewing conditions using Monte Carlo specialized software. It is shown that the temperature drop towards the peak of a groove might lead to a substantial decrease of the grooves' effective emissivity.

New transfer standard pyrometers, named "RT900" and "RT1550," operating at 900 nm and 1550 nm, respectively, have been designed, characterized, and calibrated with defined fixed points of the International Temperature Scale 1990 (ITS-90) at the National Institute of Standards and Technology (NIST). The pyrometers are designed for radiance temperature measurements in the range between the freezing temperatures of Sn (231.928 °C) and Ag (961.78 °C). These instruments also incorporate design elements optimized for compactness and portability that allow them to be used to interpolate, maintain and disseminate radiance temperature scales as well as for inter-laboratory comparisons. The calibration of the RT900 at different fixed points demonstrate agreement to within 25 mK. The size of source effect (SSE) correction for a source with a 40-mm diameter has been measured to be as low as 0.01 %.

A new capability for the measurement of the temperature-dependent emittance of specular samples in the near infrared spectral region has been developed in NIST's infrared spectrophotometry laboratory to provide emittance measurements and standards for a broad range of applications including rapid thermal processing (RTP). Our approach employs the indirect measurement of reflectance and transmittance measurements to obtain emittance. A vacuum goniometer system controls the sample environment and measurement geometry. The main system, including the sample, is contained in a vacuum chamber that enables characterization of materials otherwise susceptible to oxidation. Details of the lasers, sources, detectors, and other optics in the system are given. The system has initially been used to characterize the spectral emittance (by reflectance) of a variety of semiconductor wafer samples including bare silicon and silicon substrates coated with SiO 2, Si3N4, and polysilicon films. The spectral range for these measurements is from 600 nm to 1100 nm, where Si is opaque; the temperature range is ambient to 800degC. The results are analyzed and compared with those predicted by several models from the literature

This prospective multicenter study assessed the prevalence and feasibility of percutaneous coronary angioplasty (PTCA) in the acute phase of ST-elevation myocardial infarction (STEMI) in 3 nonacademic interventional cardiology centers (Alsace, France).We studied the clinical characteristics, angiographic data, and PCTA results of all STEMI patients and analyzed the revascularization rates and adverse events during hospitalization. We compared patients at least 75 years of age and younger patients for these data and with the literature.Of the 1672 patients admitted for STEMI, 342 (20.45%) were at least 75 years of age. Half the patients in this high-risk subgroup were women. These patients had more co-morbidities (e.g., hypertension and diabetes mellitus) than younger patients, and more of them had three-vessel disease. Mortality rate was high in this subgroup and always higher than for comparable younger subjects, but it varied according to the initial clinical profile. Their global mortality rate was 20.47%, but it fell to 5.41% when we excluded patients with cardiogenic shock or in Killip stage ill, and those who were resuscitated. PTCA is a coronary reperfusion technique especially indicated for elderly patients with STEMI. It is an effective revascularization technique, with a reperfusion rate (exclusively TIMI III flow) reaching 93.88% in the elderly group, only slightly lower than among younger patients (97.18%).PTCA is a technique particularly indicated in the elderly in Alsace because of regional geographic and medical specificities: nearby emergency services are available to virtually the entire population of Alsace, and most interventional cardiology teams apply a strategy of exclusive primary PTCA.

A new capability for the measurement of temperature-dependent emittance of specular samples in the near infrared spectral region has been developed in NIST's Infrared Spectrophotometry Laboratory. The effort is directed to support needs for emittance data and standards for a broad range of applications including rapid thermal processing (RTP). Our approach employs the indirect method of reflectance and transmittance measurements to obtain emittance and a vacuum goniometer system to control the sample environment and measurement geometry. The system has been developed for the acquisition of emittance data of specular samples and the development of standards. The heart of the system, including the sample, is contained in a vacuum chamber that enables characterization of materials otherwise susceptible to oxidation. Three diode lasers (900 nm, 950 nm, and 1560 nm) and a halogen lamp are used as radiation sources. Internal Si and InGaAs detectors and an external monochromator are used in both reflectance and transmittance modes. The spectral range of the monochromator/detectors is 600 nm to 2300 nm. A cold reference and hot sample are mounted on a horizontal stage, which in turn is mounted on a rotation stage. Reference standard samples (at room temperature) used are un-doped silicon and gold mirrors. The reflectance detector stage is also mounted on a rotation stage to enable measurement of angle dependent emittance. Optical windows and fiber optics are used for light input and output. The sample heater employs a platinum-ceramic element and allows temperatures between 100degC and > 800degC. It is shielded from the black walls of the chamber by a water-cooled shroud. The system has initially been used to characterize the spectral emittance (via reflectance) of a variety of semiconductor wafer samples including bare silicon and silicon substrates coated with SiO2, Si3 N4, and polysilicon films. The spectral range for these measurements is 600 nm to 1100 nm, where Si is opaque; the temperature range is ambient to 800degC. The results are analyzed and compared with those predicted by several models from the literature

Measurement instrumentation and methodology for temperature dependent emissivity of solid materials are under development in NIST's Fourier Transform Spectrophotometry Laboratory. The effort is directed to support US industrial needs for emissivity data and standards for a broad range of applications including rapid thermal processing (RTP). The measurement approach and instrumentation design for several systems under construction are described. In particular, a vacuum goniometer for reflectance and transmittance measurement has been designed for the characterization of the emissivity of RTP samples.

A new facility for the measurement of spectral emittance (emissivity) of materials that employs a set of blackbody sources is being built at NIST. This facility has also been used to investigate the capabilities of Fourier transform (FT) spectrometers to characterize the spectral emissivity of blackbody sources. The facility covers the spectral range of 1 μm to 20 μm and temperatures from 600 K to 1400 K. The principle of operation involves the spectral comparison of an unknown source with a group of variable temperature and fixed point reference sources by means of the FT spectrometer and filter radiometers. Sample surface temperature is measured by non-contact method using a sphere reflectometer. The current reflectometer setup allows measurements of opaque samples, but it is planned to include semitransparent materials at a later stage.

Evaluation of angioplasty for primary cardiogenic shock in acute myocardial infarction in three non-universitary alsacians centres between 1999 and 2002.One hundred and eighty-two patients were included. Hospitalisation survival rate is 43.96% after hospital discharge. One hundred and forty-nine patients were treated by primary angioplasty. Angioplasty is successful in 79.12%. The predictives factors of death are: age75, TIMI = 0 at the admission, three vessels disease. Twenty-four months survival is 91% (follow-up data available on 28.75% of the patients alive at hospital discharge).Angioplasty seems to be the right choice in case of acute myocardial infarction complicated by cardiogenic shock, the results are better than medical treatment at short- and mid-term.

Baffles are often placed in integrating spheres to accommodate the non-ideal aspects of other sphere components. These include detectors, sources, sphere wall surface shape and coatings. Baffles intentionally prevent light interchange between these and other important sphere components and regions such as entrance/exit ports, sample, reference and detector field-of-view. The challenge for an integrating sphere designer is to position and construct baffles that achieve the primary goal of shadowing specific elements from each other, while at the same time minimizing all other “side” effects that the baffles may have. Perhaps the most important side effect is the additional signal loss for light arriving at or leaving the sample from or to the baffle due to its absorptance. This is especially true for coatings and spectral ranges where the wall reflectance is relatively low such as for BaSO4 above 1.5 mm and diffuse gold. A potential improvement that we have investigated in an infrared reflectometer sphere is the use of a specular coating that has significantly higher reflectance than any other available diffuse coating. In our case we have used specular gold versus the diffuse gold-coated plasma-sprayed metal coating that is on the sphere wall. Although this provides for lower loss of light reflected from the sample onto the baffle, the side effects must also be considered and reduced in the design. Specifically one needs to consider the mirroring that will take place in the sphere. In this paper we discuss the important design issues along with some integrating sphere characterization results that demonstrate improved sphere performance by use of specular baffles.

An algorithmic model of bi-directional reflectance distribution function (BRDF) based on the ray optics approximation and microfacet model of randomly rough surface is proposed. Its central idea is that for every incident ray, the normal vector to the surface undergoes a random perturbation, and the direction of specular reflection is calculated using this perturbed normal. Such behavior of the normal can be treated within the framework of a microfacet model of randomly rough surfaces. The algorithm allows one to model reflection from both isotropic and anisotropic surfaces, with two-dimensional Gaussian and other probability density functions for the normal vector perturbations, and various geometrical attenuation functions. The proposed "perturbed normal microfacet (PNMF) model" exhibits experimentally observed effects such as increased reflectance near grazing incidence and off-specular peaks, and allows fast importance sampling. A weighted sum of Lambertian and PNMF BRDFs can be fitted to experimental data by varying the appropriate parameters. Adherence to the reciprocity principle and energy conservation law is demonstrated via results of forward and backward ray tracing. The PNMF model can be used in Monte Carlo calculations of radiative heat exchange among rough surfaces, in realistic image synthesis, lighting engineering, for modeling of such radiometric devices as blackbody radiation sources, integrating spheres in the infrared spectral range, cavity detectors of radiation, diffusely reflected panels, etc.

Incomplete hemispherical irradiation of the sample (or collection of radiation, in the reverse geometry) in an integrating sphere reflectometer is unavoidable due to sample viewing (or illumination) requirements. This means that one measures with nearly hemispherical irradiation and obtains a quantity that is not identical to the hemispherical/directional (or directional/hemispherical) reflectance factor (HDR) of the sample. The assumption that this quantity is identical to the HDR can lead to error in the measurement result, which is not generally corrected for. The error, a.k.a. “port loss error”, is minimal for comparative measurements of samples with similar reflective properties, but can easily amount to several percent for a diffuse vs. specular comparison and could be even higher for samples that exhibit strong forward scattering. Only a few papers in the literature have dealt with this issue, perhaps due to the existence of other larger sources of error. Our approach to this problem has three elements: (1) establish a definition and set of equations that quantify the error due to incomplete irradiation of the sample due to the presence of the viewing port (“port loss” uncertainty); (2) develop algorithms and computer models to predict port loss effects for a specular-diffuse sphere coating and specular-diffuse (or more general bi-directional reflectance distribution function (BRDF)) sample; (3) design a technique and instrumentation to allow routine direct measurements of port loss to correct the error; using reference standards such as an Al mirror and a polytetraflouroethylene (PTFE). Keywords : integrating sphere, reflectance, BRDF, uncertainty.

In the past decade, scales for infrared spectral regular (specular) transmittance and reflectance have been established at the National Institute of Standards and Technology (NIST). Recently, we have developed an error budget based on direct evaluation of the sources of error in the measurement process. These include the detection system non-linearity, spatial non-uniformity of the detector, misalignment of components, inter-reflection between components, asymmetry of sample and reference measurements, and source polarization effects. Here we describe the evaluation of the linearity of our measurement system that includes a Fourier transform spectrophotometer, integrating sphere and MCT detector. From the linearity results, relative responsivity curves are also established.

This study presents data on the management of acute coronary syndromes collected in a national registry organized by the french Collège national des cardiologues des hôpitaux généraux in September 2000. In all 86 institutions participated and data from 607 patients (mean age: 67 years; 413 men) were analysed. The final diagnosis was unstable angina in 38%, non-Q wave myocardial infarction in 21% and Q-wave myocardial infarction in 40.5%. Median time to admission was 4 h. At symptom onset, patients called their general practitioners in 46% of cases, emergency ambulatory units in 31% of cases and arrived to the hospital on their own in 23% of cases. Observance of the European Society of Cardiology guidelines was good for patients without ST segment elevation. In patients with ST segment elevation, 9% had pre-hospital thrombolysis, 28% hospital thrombolysis, and 27% had angioplasty within 48 h of admission, including 9% with rescue angioplasty. Overall, 57% of patients with ST segment elevation received reperfusion therapy. In hospital mortality was 6% for the whole cohort, and 11% for patients with acute myocardial infarctions. By multivariate analysis, predictors of in-hospital mortality were age, type of acute coronary syndrome, absence of beta-blocker therapy, and absence of coronary angiography.

Objective: The urban environment and familial liability are risk factors for psychotic illness, but it is not known whether a biological synergism exists between these two proxy causes. Method: The amount of biological synergism between familial liability (defined as a family history of delusions and/or hallucinations necessitating psychiatric treatment) and a five-level rating of population density of place of residence was estimated from the additive statistical interaction in a general population risk set of 5,550 individuals. Results: Both the level of urbanicity (adjusted summary odds ratio=1.57, 95% CI= 1.30–1.89) and familial liability (adjusted odds ratio=4.59, 95% CI=2.41–8.74) increased the risk for psychotic disorder, independently of each other. However, the effect of urbanicity on the additive scale was much larger for individuals with evidence of familial liability (risk difference= 2.58%) than in those without familial liability (risk difference=0.40%). An estimated 60%–70% of the individuals exposed to both urbanicity and familial liability had developed psychotic disorder because of the synergistic action of the two proxy causes. Conclusions: Given that familial clustering of psychosis is thought to reflect the effect of shared genes, the findings support a mechanism of gene-environment interaction in the causation of psychosis.

In the last two decades considerable progress has been made in numerical modeling of isothermal and non‐isothermal cavities by the Monte Carlo method, in particular, by the use of the uniform specular‐diffuse reflection model and backward ray tracing techniques. However, this technique has no essential theoretical foundation. In the present paper a comparative numerical analysis of forward and backward ray tracing algorithms shows agreement with earlier analytical results. Numerical experiments show that the use of uniform specular‐diffuse reflection model, which obeys the reciprocity principle, leads to excellent agreement between effective emissivities, computed by forward and backward ray tracing. At the same time, results obtained for the non‐reciprocal Phong’s model demonstrate substantial discrepancies.

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The development and evaluation of an optical system for a new spectral directional emittance facility at NIST is reported. The imaging quality and signal contributions due to out‐of‐field‐of‐view scattering, commonly characterized by the “size‐of‐source effect” (SSE) parameter, have been measured across the spectral range of 0.65 μm to 4 μm by three independent methods. The SSE measurement results of scatter levels not exceeding 2 to 3 parts in 104 are consistent and exceed the design targets. The potential application of the optical system to construction of a portable instrument with low scatter/emission and an operating spectral range of 0.65 μm to 20 μm are discussed.

A NIST-developed pyroelectric radiometer was characterized and calibrated to extend the NIST high accuracy spectral responsivity scale from the visible range to the ultraviolet (UV) and infrared (IR). The transmission of the gold-black coated LiNbO3 pyroelectric material is negligibly small, therefore the absorptance, equal to 1-reflectance, is proportional to the responsivity of the detector. The spectral total reflectance of the coating was measured with integrating spheres and spectrophotometers to determine the relative spectral responsivity from the UV to the IR. The relative spectral responsivity was converted into absolute spectral power and irradiance responsivities by measuring the total power in a 442 nm stabilized laser beam. The reference device for absolute calibration was a Si trap-detector calibrated against the primary standard cryogenic radiometer. The calibrations were repeated with 31 months separation. A 0.3 % long-term shift in the reflectance was measured between 800 nm and 19 μm. The 28 % reflectance at 10.6 μm scaled up the 0.1 % spatial responsivity non-uniformity in the visible (where the reflectance was 0.4 %) to 8 %. The spectral power and irradiance responsivity scales of the pyroelectric radiometer have been realized between 250 nm and 2.5 μm with a relative standard uncertainty of less than 0.34 % (coverage factor k=1).

Integrating spheres are often used as calibration sources providing uniform radiance within a solid angleand/or uniform irradiance at a distance. The best performance in such a system can be achieved if one is ableto evaluate as well as predict the important characteristics of the sphere system’s output, such as the spatialand angular distributions of radiance over the exit port, or the distribution of irradiance at the external planeof calibration. We have developed the algorithms and specialized software based on Monte Carlo techniquesto solve the problem of radiation transfer inside an integrating sphere containing several point sources andconical annular baffle. The new algorithm employs backward ray tracing coupled with the “shadow rays”technique. As a timesaving procedure, the axial symmetry of the sphere and the superposition principle areused to substitute the sum of single source radiation fields rotated through a specific angle, for the radiationfield of the complete multiple source sphere. The random (due to the stochastic character of the Monte Carlomethod) component of uncertainty for the radiance or irradiance results is less than 0.1%. The results ofnumerical experiments are used to establish the performance variation as a function of the reflectance andspecularity of the sphere wall, the number of radiation sources, the type of baffle used, and the angulardistribution of their radiant intensity.Keywords: integrating sphere, uniform source, radiance, irradiance, calibration, Monte Carlo, simulation,modeling, ray tracing

An integrating-sphere system has been designed and constructed for multiple optical properties measurement in the IR spectral range. In particular, for specular samples, the absolute transmittance and reflectance can be measured directly with high accuracy and the absorptance can be obtained from these by simple calculation. These properties are measured with a Fourier transform spectrophotometer for several samples of both opaque and transmitting materials. The expanded uncertainties of the measurements are shown to be less than 0.003 (absolute) over most of the detector-limited working spectral range of 2 to 18 µm. The sphere is manipulated by means of two rotation stages that enable the ports on the sphere to be rearranged in any orientation relative to the input beam. Although the sphere system is used for infrared spectral measurements, the measurement method, design principles, and features are generally applicable to other wavelengths as well.

Stress may be a contributing factor in intestinal inflammatory disease; however, the underlying mechanisms have not been elucidated. We previously reported that acute stress altered jejunal epithelial physiology. In this study, we examined both physical and psychological stress-induced functional changes in colonic mucosa. Colonic mucosal tissue from rats subjected to either 2 hr of cold-restraint stress or 1 hr of water-avoidance stress demonstrated altered ionic transport as well as significantly elevated baseline conductance (ionic permeability) and flux of horseradish peroxidase (macromolecular permeability). Intraperitoneal pretreatment with the corticotropin-releasing hormone (CRH) antagonist, a helical CRH(9-41), inhibited the stress-induced abnormalities, while exogenous intraperitoneal administration of CRH, to control rats, mimicked the stress responses and in vitro CRH increased the macromolecular permeability. These results suggest that peripheral CRH mediates stress-induced colonic pathophysiology. We speculate that a stress-induced barrier defect may allow uptake of immunogenic substances into the colonic mucosa, initiating or exacerbating intestinal inflammation.

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The hypothesis that psychosis exists in nature as a distribution of symptoms is not so bold as it may seem [1]. For example, in the case of depression, both genetic and community studies suggest that the phenotype is more likely to exist as a continuous (albeit skewed, [2]) distribution of symptoms rather than a true disease dichotomy [3-6]. Given the substantial degree of overlap in terms of psychopathology, outcome, risk factors and treatment between depression and psychosis [7], it is unlikely that psychosis, contrary to depression, would have a completely non-continuous, dichotomous distribution. Although possibly more skewed because of their lower prevalence, a degree of continuity in the distribution of symptoms would be expected. This hypothesis, however, has attracted relatively little research effort, especially from the psychiatric profession [8].

Item does not contain fulltext Background Psychotic disorders are more common in urban environments. It is not known whether the increase in risk applies to both the positive and negative dimensions of psychosis. Methods In a random general population sample of 7076, measures of positive and negative symptoms of psychosis were constructed using Composite International Diagnostic Interview (CIDI) data. Three CIDI observed items of flat affect, retarded speech and retarded movement served as indicators of a negative symptom variable. Results Both negative and positive symptoms of psychosis were, independent of each other, associated with a five-level measure of population density of place of residence (adjusted OR negative symptoms: 1.42, 95% CI: 1.18, 1.71; adjusted OR positive symptoms: 1.19, 95% CI: 1.13, 1.24). These associations remained after exclusion of vulnerable individuals with any lifetime psychiatric disorder (n = 2910), any lifetime psychiatric treatment (n = 1352) and history of psychosis in the parents (n = 142). Conclusions An environmental risk factor associated with urbanicity may act in early life to nonspecifically influence risk for both negative and positive experience of psychosis, regardless of whether a formal psychiatric disorder is diagnosable.

The sections in this article are Introduction Vapor-Phase Standards Condensed-Phase Standards Calibration Methodology Sources of Error Use of Low- versus High-Resolution Standards Absorption Band (Peak) Wavenumber Evaluation Methods Conclusions

The sections in this article are Introduction Terminology Historical Review Theory of Sphere Throughput Reflectance Techniques Absolute Reflectance Methods Relative Reflectance Methods Dealing with Error Sources: Sphere Design Considerations Detector Field of View and Sphere Symmetry Baffle Design Coating and Sample BRDF Flat versus Curved Samples Port Design Modern Sphere Instrumentation for Spectroscopy Summary and Discussion Disclaimer Appendix

The reaction of a silsesquioxane trisilanol with methylmagnesium chloride leads to an unprecedented tetranuclear magnesium silsesquioxane complex 1 in high yield. The crystal structure shows an unusually short Mg-Cl bond, indicative of an electron-deficient magnesium atom; 1 has been used as transmetalation agent for the synthesis of metal silsesquioxane complexes. Transmetalation activity was low, but can easily be followed by multinuclear NMR. Crystal data for 1: C(78)H(142)Cl(2)Mg(4)O(26)Si(14).6(C(4)H(8)O), a = 15.744(1) A, b = 26.526(2) A, c = 16.917(1) A, beta = 113.229(2) degrees, monoclinic, P2(1)/n, Z = 2.

An athabatic laser calorimeter has been developed with a sensitivity of the order of 106 cm1with one watt of laser power using a C02 laser (9 t m to 1 1 ji m ) in the infrared region. The heat leakby conduction and by rathation from a sample to an inner isothermal enclosure is enough small to beignored because we succeeded in developing the temperature tracking system between the sample andthe enclosure. The total uncertainty of absorptioncoefficient measurements is estimated to be 5.7 %.The absorption coefficient of a potassium chloride sample #2 was (3. 17 0. 18) X lO cm'.Keywords rate laser calorimeter, athabatic lase:r calorimeter, low absorption coefficient, electricalcalibration, potassium chloride, temperature tracking, 1.INTRODUCTION In recent years progress has been made in the fabrication of low loss optical materials for theinfrared region as well as the visible region, and this has made it necessary to develop new techniques for measuring bulk and surface absorption in the lO to lO8 range, because up to the present the

We have performed regular spectral transmittance and reflectance measurements over the 1 (mu) m to 2.5 (mu) m wavelength region on several different types of materials using three different spectrophotometer systems. Two of the systems employ grating-based monochromators and InGaAs photovoltaic detectors. The beam at the sample position is nearly collimated. The other system uses an FTIR (Fourier Transform Infrared) spectrophometer as a source and a diffuse Au-coated integrating sphere with a photoconductive HgCdTe detector. In this system, the sample is placed at the focus of an f/6 converging beam. Measurements are performed on transmissive materials as well as either highly reflective or absorptive mirrors and the results are compared, taking into account any differences in beam geometry and polarization among the different systems.

Several peak determination algorithms are described and compared using the spectra of a NIST wavelenght/wavenumber standard reference material (SRM). These methods are the (1) centroid (or center of gravity) (with fraction value 0.5), (2) extrapolated centroid, (3) extrapolated bisecting, (4) polynomial curve fit, and (5) absolute maximum (minimum) methods. Comparisons are made of the peak wavelength value accuracy and reproducibility, versatility and other aspects of the peak determination methods. Optimization studies of the centroid, extrapolated centroid, and extrapolated bisecting peak determination methods, used for several NIST SRM's, have found that the peak value accuracy and precision can be improved by careful selection of peak fraction, spectral data density and polynomials fitting order (for extrapolated algorithms).

A goniometric system is used in conjunction with an FT-IR (Fourier- Transform Infrared) spectrophotometer to perform reflectance and transmittance measurements as a function of angle of incidence from 12$DEG to 80$DEG. The input beam is polarized using a high-quality Ge reflective Brewster-angle polarizer, and is focussed onto the sample with an approximately f/50 geometry. The average angle of incidence is controlled to within +/- 0.05$DEG, and spectra are recorded for both s- and p-polarization over a wavelength range of 1.6 (mu) m to 5.2 (mu) m, using a photoconductive InSb detector. Measurement results are compared to the predictions of the Fresnel equations in order to assess the accuracy of the instrument.

A Fourier transform IR spectrometer-based broadband IR ellipsometer has been developed around a pair of high- quality Brewster angle polarizers. These polarizers consist of four Ge plates in a chevron geometry and have been measured to have extinction ratios of less than 10-5 in the IR spectral region. The ellipsometer can be used in transmission or reflection mode for angles of incidence of 100 to near grazing. We describe the design and construction of the ellipsometer and initial testing of the system using measurements on Si wafers from 2 micrometers to 12 micrometers wavelength. 5© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.