ORMOCHALCs: organically modified chalcogenide polymers for infrared optics.

A novel method combining elemental sulfur and selenium was developed, yielding crystalline sulfur-selenium compounds. The compounds were melted, and an organic comonomer added. Once the organic comonomer was consumed, the viscous compound was vitrified and allowed to cool yielding organic-inorganic hybrid polymers that are termed Organically Modified Chalcogenide (ORMOCHALC) polymers.

Low-temperature deposition of BaCuSF, a visible through mid-infrared p-type transparent conductor.

Barium copper sulfur fluoride (BaCuSF) is a p-type transparent conductor (p-TC) that, when doped with potassium, exhibits exceptionally high conductivity. The results of a detailed optical and electronic characterization of BaCuSF thin films deposited at a substrate temperature of 100 °C are presented. X-ray diffractometry shows the presence of a cubic BaCuSF phase. Spectroscopic measurements demonstrate that the films transmit from the visible through the mid-infrared with a band gap of 1.8 eV. Hall measurements indicate that the material is a degenerate semiconductor. As deposited, the films exhibit conductivity at room temperature of approximately 260 S/cm - among the highest reported room temperature conductivities for p-TCs. After post-deposition treatment in water, their conductivity increases to as high as 800 S/cm, and their band gap is reduced to 1.5 eV. The potential for low temperature deposition of p-type films with high conductivity and optical transmittance makes BaCuSF promising for several applications including flexible electronics and photovoltaics.

Nonlinear electronic line shape determination in Yb3+-doped phosphate glass.

Nonlinear refraction spectroscopy has been performed in Yb3+-doped phosphate glass to determinate the line shape of real and imaginary parts of n2 (n2' and n2"). The n2' spectrum presented an asymmetric feature due to the interference of resonant and nonresonant contributions, where the nonresonant term arises from the polarizability difference between excited and ground states (delta alpha). The measurements were performed in the transient regime to determine population dynamics and the pump saturation intensity at 975 nm (peak of the absorption spectrum). Because of the small quantum defect of Yb3+, we estimated that the magnitude of the thermal lens effect is approximately 20 times smaller than the population lens effect, caused by n2.

Development and use of a virtual NMR facility.

We have developed a "virtual NMR facility" (VNMRF) to enhance access to the NMR spectrometers in Pacific Northwest National Laboratory's Environmental Molecular Sciences Laboratory (EMSL). We use the term virtual facility to describe a real NMR facility made accessible via the Internet. The VNMRF combines secure remote operation of the EMSL's NMR spectrometers over the Internet with real-time videoconferencing, remotely controlled laboratory cameras, real-time computer display sharing, a Web-based electronic laboratory notebook, and other capabilities. Remote VNMRF users can see and converse with EMSL researchers, directly and securely control the EMSL spectrometers, and collaboratively analyze results. A customized Electronic Laboratory Notebook allows interactive Web-based access to group notes, experimental parameters, proposed molecular structures, and other aspects of a research project. This paper describes our experience developing a VNMRF and details the specific capabilities available through the EMSL VNMRF. We show how the VNMRF has evolved during a test project and present an evaluation of its impact in the EMSL and its potential as a model for other scientific facilities. All Collaboratory software used in the VNMRF is freely available from www.emsl.pnl.gov:2080/docs/collab.

Ozone and particulate matter air pollution in Wisconsin: trends and estimates of health effects.

OBJECTIVES: Ozone and particulate matter 10 microns in diameter or less (PM10) are associated with increased risk of morbidity and mortality. This paper will report ozone and PM10 trends in Wisconsin and provide estimates of potentially susceptible populations and adverse health outcomes associated with current levels of these pollutants. METHODS: Ozone and PM10 monitoring data is provided by Department of Natural Resources (DNR) air monitors. Exposure-response modeling and data, provided by the United States Environmental Protection Agency (US EPA), was used to estimate hospital admissions associated with ozone and PM10 pollution. RESULTS: Days with high ozone concentrations have become less frequent and the annual PM10 levels have decreased over the 1990s. However, the potentially susceptible population has increased, the number of children who could experience a lung function decrement due to ozone is between 12,978 and 38,653, and high PM10 concentrations are estimated to have resulted in 43 hospital admissions. CONCLUSION: Despite decreasing ozone and PM10 levels, the burden of respiratory and cardiovascular disease affected by these pollutants remains significant.

Clinical consultations using store-and-forward telemedicine technology.

OBJECTIVE: To investigate the potential role of a store-and-forward (SAF) telemedicine system in specialty consultations initiated by primary care physicians. MATERIALS AND METHODS: In this pilot telemedicine study, patients needing consultations in cardiology, dermatology, endocrinology, and orthopedics had both standard face-to-face (FTF) consultations and SAF consultations. RESULTS: Fifteen patients had both FTF and SAF consultations, 4 had echocardiograms transmitted for an SAF consultation only, and 1 had an SAF consultation but no FTF appointment. Of 19 diagnoses made, all were essentially the same in both types of consultations; 14 of 15 FTF consultations and 15 of 19 SAF consultations resulted in additional treatment recommendations. CONCLUSIONS: While it was possible to develop a desktop system for SAF consultations, the equipment was not adequately integrated. Without total digital input, including electronic patient medical records, packaging of information is laborious and impractical. Seamlessly adapting to existing clinical practice is vital. Issues such as increasing work for the physicians or office staff, gathering adequate patient information, and designing a referral process were more difficult than we had anticipated. Patient acceptance was high, but the clinical pilot had very small numbers.

Testing of household products and materials for emission of toluene diisocyanate.

Polyurethane products were subjected to chamber testing to determine their emission rates of 2,4- and 2,6-toluene diisocyanate (TDI). The polyurethane (PU) products included carpet padding, furniture cushions, sheet foam, varnishes, and sealants, as well as a commercially-applied water sealant product for concrete that contained up to 4 percent TDI by weight. The PU products were screened in a 9-L glass chamber, under elevated temperature and chamber loading conditions, using both a time-integrated sampling and analysis method specific for TDI and a continuous but non-specific real-time monitor for isocyanates. None of the products normally found in residences showed a positive response in the screening tests, indicating that TDI emissions and consequently toxic effects from such products are negligible. However, the commercially-applied water sealant gave a positive response in the screening test. Further testing of that product at realistic temperatures showed initial TDI emission rates of about 300,000 micrograms/m2/hr, with emissions lasting only one hour or less. At 21 and 27 degrees C, about 1 percent and 5 percent, respectively, of the TDI content of the product was released to the air. The emitted TDI was predominantly the 2,6-isomer, although the TDI originally present in the product was predominantly the 2,4-isomer.

Cell wall antigens of Pneumocystis carinii trophozoites and cysts: purification and carbohydrate analysis of these glycoproteins.

We have purified and biochemically analyzed individual cell wall glycoproteins of Pneumocystis carinii. Our results show that corresponding core glycoproteins constitute the cell wall antigens in both trophozoites and cysts, and glycosylation of these glycoproteins does not appear to be significantly altered during development. Cysts and trophozoites in rat-derived organism preparations were separated from each other by counterflow centrifugal elutriation, then treated with Zymolyase to obtain the cell wall fractions. Gel electrophoresis patterns of these fractions from both life-cycle stages were qualitatively similar. Ten major antigenic glycoproteins in these fractions were purified by preparative continuous elution gel electrophoresis. All ten glycoproteins from cysts and trophozoites contained mannose, glucose, galactose, and N-acetylglucosamine, and some contained traces of fucose. The glycoproteins of cysts had more mannose than their trophozoite counterparts. The trophozoite glycoproteins differed from those of the cyst by the presence of xylose. To examine the species-specificity of glycoprotein glycosylation, preparations of human-derived P. carinii (comprised of mixed life-cycle stages) were also examined and found to contain the same sugars as those found in rat-derived organisms. Most of the purified rat-derived glycoproteins bound Concanvalin A, which was abolished by treatment with N-glycanase. This suggested that the majority of the oligosaccharides were N-linked to the proteins, but attempts to identify carbohydrate linkage sites by amino acid sequencing were hampered by apparent modifications of residues. The peptides derived by cyanogen bromide cleavage revealed distinct size patterns for each glycoprotein, suggesting that they were distinct proteins. Most of the glycoproteins reacted with monoclonal antibodies which recognize a highly conserved epitope on rat P. carinii. Four of the individually purified glycoprotein preparations elicited in vitro cellular immune responses, implicating their involvement in the recognition of P. carinii by host T cells. The identification and characterization of P. carinii cell wall proteins will be helpful in analyzing the relationship of the organism to its mammalian host.

Attenuation of propranolol-induced bronchoconstriction by frusemide.

BACKGROUND: Inhaled propranolol causes bronchoconstriction in asthmatic subjects by an indirect mechanism which remains unclear. Inhaled frusemide has been shown to attenuate a number of indirectly acting bronchoconstrictor challenges. The aim of this study was to investigate whether frusemide could protect against propranolol-induced bronchoconstriction in patients with stable mild asthma. METHODS: Twelve asthmatic subjects were studied on three separate days. At the first visit subjects inhaled increasing doubling concentrations of propranolol (0.25-32 mg/ml), breathing tidally from a jet nebuliser. The provocative concentration of propranolol causing a 20% reduction in FEV1 (PC20FEV1 propranolol) was determined from the log concentration-response curve for each subject. At the following visits nebulised frusemide (4 ml x 10 mg/ml) or placebo (isotonic saline) was administered in a randomised, double blind, crossover fashion. FEV1 was measured immediately before and five minutes after drug administration. Individual PC20FEV1 propranolol was then administered and FEV1 was recorded at five minute intervals for 15 minutes. Residual bronchoconstriction was reversed with nebulised salbutamol. RESULTS: Frusemide had no acute bronchodilator effect but significantly reduced the maximum fall in FEV1 due to propranolol: mean fall 18.2% after placebo and 11.8% after frusemide. The median difference in maximum % fall in FEV1 within individuals between study days was 3.6% (95% CI 1.2 to 11.7). CONCLUSIONS: Frusemide attenuates propranolol-induced bronchoconstriction, a property shared with sodium cromoglycate. Both drugs block other indirect challenges and the present study lends further support to the suggestion that frusemide and cromoglycate share a similar mechanism of action in the airways.

The role of the plant properties in point-to-point arm movements: a robustness study.

In recent papers we demonstrated by means of a modeling study that the smoothness of hand paths and the bell-shaped character of hand velocity profiles which have been experimentally observed in point-to-point arm movements can be largely attributed to the biomechanical properties of the arm rather than to specific planning by the central nervous system. In this paper we present a study of the robustness of our earlier results comprising two goals: (i) the determination of the range of model parameters for which such observations remain valid, (ii) the identification of possible relationships between model parameters and kinematic variables. The results of this study imply three conclusions: (i) the valid range of the tested model parameters (namely the main muscle parameters) is large, (ii) the modeled phenomena are well behaved in that parametric changes do not give rise to bifurcations or other behavioral discontinuities in the analyzed ranges, (iii) there exist precise relationships between certain muscle parameters and the time course of the hand velocity. These results point out that the phenomena observed in our previous work are indeed robust and can lead to useful insights into the mechanisms comprising the regulatory action of the central nervous system as well as into the design principles for biologically inspired artificial arms.

The role of plant properties in arm trajectory formation: a neural network study.

In this paper, we first introduce a neural network model of a planar, six-muscle, redundant arm whose structure and operation principles were inspired by those of the human arm. We developed the model with a motor-learning framework in mind, i.e., with the long-term goal of incorporating it in a parallel distributed learning scheme for the arm controller. We then demonstrate the response of the model to various patterns of activation of the arm muscles in order to study the relative role of control strategies and plant properties in trajectory formation. The results of our simulations emphasize the role of the intrinsic properties of the plant in generating movements with anthropomorphic qualities such as smoothness and unimodal velocity profiles, and demonstrate that the task of an eventual controller for the arm could be simply that of programming the amplitudes and durations of steps of neural input without considering additional motor details. Our findings are relevant to the design of artificial arms and, with some caveats, to the study of the brain strategies in the arm motor system.

Pathogenesis of caprine arthritis encephalitis virus. Cellular localization of viral transcripts in tissues of infected goats.

Pathologic specimens of 18 goats with classical lesions of caprine arthritis-encephalitis (CAE) virus infection were examined morphologically and by in situ hybridization using molecularly cloned CAEV deoxyribonucleic acid (DNA) to determine which tissues and cells of naturally infected goats supported virus replication. Large numbers of cells with viral transcripts were detected in inflamed brain, spinal cord, lung, joints, and mammary gland. These cells were morphologically compatible with macrophages. Fewer cells with viral transcripts were seen in noninflamed tissues. Viral RNA was identified in macrophagelike cells in lung, liver, spleen, and lymph nodes, in cells lining the vessels of brain and synovium, and in epithelial cells of intestinal crypts, renal tubules, and thyroid follicles. These data suggest that the cell tropism of lentiviruses may extend beyond the narrow boundaries of lymphocytes and macrophages.

Development and application of immunocytochemical staining techniques: a review.

Since the field of immunocytochemistry was pioneered almost half a century ago, over 30 different immunostaining methods have been developed. Most laboratory investigators, however, are aware of only a few of the more popular techniques. This article, therefore, reviews and places in historical perspective many of the less common methodologies. A discussion of the progression of immunostaining methodology from purely immunologic techniques (employing only antigens, antibodies, and free enzymatic preparations) to procedures that use non-immunologic substances (such as avidin, biotin, and protein A) is presented. Basic principles of immunostaining, including specimen preparation, fixation, control procedures, interpretation, and problems unique to cytopathology, are also discussed. Schematic diagrams that illustrate the nature and arrangement of the immunochemical reagents employed in most of these techniques are provided in order to demonstrate how various materials can be combined to create a desired staining effect.

Applications of combination wavelength (1060-nm and 530-nm) and pulsed Nd:YAG laser for contact laser surgery.

Two pulsed neodimium yittrium aluminum garnet (Nd:YAG) laser systems were evaluated for contact surgery through a fiberoptic system with a sapphire tip. Pulsed Nd:YAG laser at 1060 nm was as effective as continuous-wave Nd:YAG laser in producing tissue incisions. A combination of 1060-nm and 530-nm wavelengths achieved smooth cutting at lower energy levels. Corneal endothelial cell damage occurred at the high power level (7 watts) required for smooth underwater incisions with both continuous wave and pulsed lasers.

Sensitive and specific monoclonal antibody recognition of human lung cancer antigen on preserved sputum cells: a new approach to early lung cancer detection.

Murine monoclonal antibodies (Mabs) to a glycolipid antigen of small-cell (SCC) and a protein antigen of non-small-cell lung cancer (NSCC) were applied to preserved sputum specimens from individuals who participated in The Johns Hopkins Lung Project (JHLP). In that study, undertaken in 1973 to evaluate the efficacy of sputum cytology screening, half of the high-risk participants (5,226 men, greater than or equal to 45 years of age, currently smoking greater than or equal to 1 pack of cigarettes per day) were randomly assigned to produce specimens for cytopathological analysis. During regular screenings over the next 5 to 8 years, 626 (12%) showed moderate (or greater) atypia. Sixty-nine of these (26 who progressed to cancer, 43 who did not) were randomly selected for a blinded improved Mab immunostaining protocol in the present study. Satisfactory specimens with morphologic atypia immunostained positively in 14 of the 22 patients who eventually progressed to cancer (sensitivity 64%), and were nonreactive in 35 of the 40 patients who did not progress to lung cancer (specificity 88%). Review of the true positive specimens (14/22 atypias) showed that they were collected 24 months in advance of diagnosis. In contrast, the 8/22 false negative atypias (failure to stain) showed that they were collected for an average of 57 months preceding the diagnosis of cancer. Subsequent specimens (average, 26 months before cancer) from participants who were originally considered "false negative" did stain positively improving sensitivity to 91% among specimens collected for an average of 2 years in advance of the clinical appearance of lung cancer. Specificity remained at 88%. Recognition of neoplastic antigen expression 2 years in advance of clinical cancer may be a valuable intermediate end point in studies of lung cancer prevention, detection, and therapy.

The INTERNIST-1/QUICK MEDICAL REFERENCE project--status report.

INTERNIST-1 and its successor, QUICK MEDICAL REFERENCE (QMR), are computer programs designed to provide health care professionals with diagnostic assistance in general internal medicine. Both programs rely on the INTERNIST-1 computerized knowledge base, which comprehensively describes 570 diseases in internal medicine. The philosophies behind the development of each program differ. Whereas INTERNIST-1 functions solely as a high-powered diagnostic consultant program, the QMR program acts more as an information tool, providing users with multiple ways of reviewing and manipulating the diagnostic information in the program's knowledge base. At the lowest level, the program can be viewed as an electronic textbook of medicine. In addition, the QMR program has the ability to assist users with generating hypotheses in complex patient cases. The QMR program has not been evaluated formally as an information tool for practicing physicians. A preliminary study indicates that QMR's case-analysis capabilities are of potential benefit in most patients in internal medicine admitted for diagnostic evaluation.

The computer as a diagnostic consultant, with emphasis on use of laboratory data.

In this preliminary study concerning the applicability of expert computer systems, such as INTERNIST-I, to providing advice to clinical pathologists regarding patients' diagnoses and the pertinence of performing further laboratory tests, 32 complex cases, drawn from Case Records of the Massachusetts General Hospital, were analyzed diagnostically by computer, on the basis of clinical laboratory data only. Half (16 cases) were diagnosed correctly, but in 15 of the rest no diagnostic conclusion could be reached. However, no diagnostic errors were made. The study provides preliminary evidence that expert computer systems can be useful to clinical pathologists and clinical internists in guiding the laboratory workup of patients toward correct diagnosis.