Calibration and evaluation of nitric acid and ammonia permeation tubes by UV optical absorption

An ultraviolet (UV) optical absorption system has been developed for absolute calibrations of nitric acid (HNO3) and ammonia (NH3) permeation tube emission rates. Using this technique, dilute mixtures containing NH3 or HNO3, both of which interact strongly with many surfaces, are accurately measured at levels below a part per million by volume. This compact and portable instrument operates continuously and autonomously to rapidly (<1 h) quantify the emission of trace gases from permeation devices that are commonly used to calibrate air-monitoring instruments. The output from several HNO3 and NH3 permeation tubes, with emission rates that ranged between 13 and 150 ng/min, was examined as a function of temperature, pressure, and carrier gas flow. Absorptions of 0.015% can be detected which allows a precision (3sigma) of +/-1 ng/min for the HNO3 and NH3 permeation tubes studied here. The accuracy of the measurements, which relies on published UV absorption cross sections, is estimated to be +/-10%. Measurements of permeation tube emission rates using ion chromatography analysis are made to further assess measurement accuracy. The output from the HNO3 and NH3 permeation tubes examined here was stable over the study period, which ranged between 3 months and 1 year for each permeation tube.     

Implementation of similarity model in the CSB system for chemical reaction predictions

A new algorithm for predicting the course of chemical reactions, implemented in the CSB system is presented. It allows to use of four various models for reaction generation, that lead to create different solution space according to the needs of the user. Depending on the chosen model one can expect solutions featuring great completeness or great reliability.     

Joint Source–Channel Communication for Distributed Estimation in Sensor Networks

Power and bandwidth are scarce resources in dense wireless sensor networks and it is widely recognized that joint optimization of the operations of sensing, processing and communication can result in significant savings in the use of network resources. In this paper, a distributed joint source-channel communication architecture is proposed for energy-efficient estimation of sensor field data at a distant destination and the corresponding relationships between power, distortion, and latency are analyzed as a function of number of sensor nodes. The approach is applicable to a broad class of sensed signal fields and is based on distributed computation of appropriately chosen projections of sensor data at the destination - phase-coherent transmissions from the sensor nodes enable exploitation of the distributed beamforming gain for energy efficiency. Random projections are used when little or no prior knowledge is available about the signal field. Distinct features of the proposed scheme include: (1) processing and communication are combined into one distributed projection operation; (2) it virtually eliminates the need for in-network processing and communication; (3) given sufficient prior knowledge about the sensed data, consistent estimation is possible with increasing sensor density even with vanishing total network power; and (4) consistent signal estimation is possible with power and latency requirements growing at most sublinearly with the number of sensor nodes even when little or no prior knowledge about the sensed data is assumed at the sensor nodes.     

Experiencing Nature: Embodying Animals in Immersive Virtual Environments Increases Inclusion of Nature in Self and Involvement With Nature

Immersive virtual environments (IVEs) produce simulations that mimic unmediated sensory experiences. 3 experiments (N = 228) tested how different modalities increase environmental involvement by allowing users to inhabit the body of animals in IVEs or watch the experience on video. Embodying sensory‐rich experiences of animals in IVEs led to greater feeling of embodiment, perception of being present in the virtual world, and interconnection between the self and nature compared to video. Heightened interconnection with nature elicited greater perceptions of imminence of the environmental risk and involvement with nature, which persisted for 1 week. Although the effect sizes were small to moderate, findings suggest that embodied experiences in IVEs may be an effective tool to promote involvement with environmental issues.     

Scaling planar silicon devices

The generation-over-generation scaling of critical CMOS technology parameters is ultimately bound by nonscalable limitations, such as the thermal voltage and the elementary electronic charge. Sustained improvement in performance and density has required the introduction of new device structures and materials. Partially depleted SOI, a most recent MOSFET innovation, has extended VLSI performance while introducing unique idiosyncrasies. Fully depleted SOI is one logical extension of this device design direction. Gate dielectric tunneling, device self-heating, and single-event upsets present developers of these next-generation devices with new challenges. Strained silicon and high-permittivity gate dielectric are examples of new materials that will enable CMOS developers to continue to deliver device performance enhancements in the sub-100 nm regime.     

Beyond Heparinization: Design of Highly Potent Thrombin Inhibitors Suitable for Surface Coupling

During extracorporeal circulation, when blood comes in contact with artificial surfaces, patients receive a standard treatment with anticoagulants to avoid blood coagulation. Dialysis patients in particular are systemically treated with heparin up to four times a week, causing a high burden for the body. For potential anticoagulant modification of external materials, such as dialysis equipment, a series of highly potent thrombin inhibitors was developed. All inhibitors share the general formula arylsulfonyl‐P3‐Pro‐4‐amidinobenzylamide, where P3 is glycyl or a trifunctional amino acid residue in L ‐configuration. Among this series, several derivatives inhibit thrombin with K_i values of less than 1 nM . Specificity measurements revealed that this inhibitor type is highly specific for thrombin with negligible activity against related trypsin‐like serine proteases. X‐ray analysis of the most potent analogue in complex with thrombin demonstrated that the N‐terminal arylsulfonyl group occupies the aryl binding site, whereas the P3 side chain is directed into the solvent and therefore is well suited for further coupling. Based on their in vitro profile, these inhibitors are suitable candidates for the development of hemocompatible materials with anticoagulant properties.     

Imaging evaluation of artificial nipples during bottle feeding

OBJECTIVE: To report a case of probable famotidine-induced mixed hepatocellular jaundice. CASE SUMMARY: A 55-year-old man presented with a one-month history of mid-epigastric pain. Initial physical examination and laboratory studies, including liver enzyme concentration tests, were unrevealing. A diagnosis of gastritis was made and ranitidine was prescribed. Following one week of therapy, the patient's symptoms had not improved and therapy was changed to famotidine and sucralfate. Approximately one week later the patient presented with jaundice. Liver enzyme concentrations were elevated and the patient was hospitalized for further evaluation. Five days following discontinuation of famotidine, liver enzyme concentrations were normal and jaundice had resolved. Further tests did not reveal any pathologic etiology. DISCUSSION: Hepatic changes have occurred in patients receiving histamine2-antagonists; ranitidine and cimetidine have been cited most frequently. In general, the elevations are mild, transient, and return to baseline with continued therapy. This is one of the first case reports of probable famotidine-induced mixed hepatocellular jaundice. CONCLUSIONS: There was a temporal relationship between the patient's signs and symptoms and initiation of famotidine. No identifiable factors contributed to the elevated liver enzyme concentrations and jaundice.     

Effect of lanthanide ions on the phase behavior of dipalmitoylphosphatidylcholine multilamellar liposomes

The effect of lanthanide ions (Ln3+) and their coordination compounds of diethylenetriamine pentaacetic acid (DTPA) on the phase behavior of dipalmitoylphosphatidylcholine (DPPC) multi-lamellar liposomes has been studied by differential scanning calorimetry (DSC), Raman spectroscopy, and freeze-fracture electron microscopic techniques. The displacement of Ca2+ binding on DPPC liposomes by lanthanide ions was also studied. The results show that the binding degree of four kinds of chloride salts with DPPC liposomes is: YbCl3 > GdCl3 > LaCl3 > CaCl2. Lanthanide ions increase the phase transition temperature of DPPC liposomes and decrease the membrane fluidity. Freeze-fracture electron microscopic results show that La3+ enhances the order of DPPC membrane. The effect of coordination compounds of lanthanides with DTPA on the phase behavior of DPPC liposomes is smaller than that of their chlorides. La3+, Gd3+, and Yb3+, can displace Ca2+ binding on DPPC liposomes, but there coordination compounds of DTPA can hardly displace Ca2+. Raman spectroscopic results show that a very slight effect in lateral packing order of DPPC liposomes was observed at various concentrations of lanthanides.