Temperature sounding by RASS with wind profiler radars: apreliminary study

The radio acoustic sounding system (RASS) is a method of remotely measuring atmospheric temperature profiles by combining acoustic and radar techniques. This method has been applied to wind profiler radars in Colorado, and excellent performance in both height coverage and accuracy has been obtained. Various acoustic source functions are examined, and it is shown that FM-CW acoustic signals are less susceptible to error than pulsed acoustic systems when using pulsed radars for RASS. The remotely determined temperature profiles are compared with co-located radiosonde soundings, and good agreement is found     

Separation of methane and nitrogen using ionic liquidic zeolites by pressure vacuum swing adsorption

The separation of methane (CH₄) and nitrogen (N₂) is a significant challenge to the enrichment and utilization of low concentration CH₄ due to the similarity in the physical and chemical properties of the two molecules. In this work, we investigated the separation of CH₄ from N₂ using 100 kg of a new ionic liquidic zeolite (ILZ) material in a 6-bed pilot-scale pressure swing adsorption process. Feed gases with CH₄ concentrations of 5.0% and 16.1% were upgraded to 11.5% and 34.6%, respectively, with CH₄ recoveries higher than 80%. The pilot test results were used to anchor a numerical model that then allowed the efficient investigation of multiple operational parameters including desorption pressure and feed gas flow rates. The numerical model produced CH₄ concentrations for both product streams consistent with those measured in the pilot experiments, with root mean square deviations below 2%. The modeling results revealed that sufficiently low desorption pressures can unexpectedly lead to lower heavy product purities under limited feed gas flow conditions. Furthermore, the optimum feed gas flow rate under which maximum heavy product purity is achieved increases with lower desorption pressure. The maximum CH₄ concentrations increased from 31.8% to 41.5%, as desorption pressures decreased from 22.8 to 12.2 kPa for optimum feed flow rates between 78.2 and 105.5 mol/h. We also demonstrate a method of process optimization based on the bed capacity ratio, ℂ, which provides a scale-independent measure of the degree to which the column is being used effectively. By varying feed flow rate and/or desorption pressure, ℂ values between 0.2 and 0.8 were explored, with maxima in the combined separation performance metric (methane recovery) × (methane purity) occurring for values of ℂ in the range 0.29–0.36. This separation performance optimization by adjusting ℂ provides an effective strategy for integrating and understanding the impact of multiple operating parameters.     

Engineering Urban Complexity: Bespoke Integrated Design

Rapid urbanisation across the globe and far-reaching technological changes are transforming urban design. Building Information modelling (BIM) is combining 3D modelling techniques and the employment of rich datasets, which is eliding the gap between the disciplines of architecture and engineering. This is enabling the introduction of a new level of complexity in the modelling of cities and the simulation and testing of urban and environmental conditions. Rob May , an Associate Director at BuroHappold Engineering and the leader of the structures team in Beijing, reflects on the potential of complex bespoke processes for creative problem-solving in the urban context.     

Aurones as modulators of ABCG2 and ABCB1: synthesis and structure-activity relationships

The ability of aurones to modulate the efflux activities of ABCG2 and ABCB1 was investigated by quantifying their effects on the accumulation of pheophorbide?A (PhA) in ABCG2-overexpressing MDA-MB-231/R cells and calcein?AM in ABCB1-overexpressing MDCKII/MDR1 cells. Key structural features for interactions at both ABCG2 and ABCB1 are a methoxylated ring?A, an intact exocyclic double bond, and the location of the carbonyl bond on ring?C. Modifications on rings?B and C were less critical and served primarily to moderate activity and selectivity for one or both transporters. These SAR trends were quantified by Free-Wilson analyses and are reflected in a pharmacophore model for PhA accumulation. Several compounds were found to be equipotent with fumitremorgin?C (FTC) in promoting PhA accumulation, and they also demonstrated strong affinities for ABCB1. These compounds were disubstituted on ring?B with methoxy or a combination of methoxy and hydroxy groups. Taken together, our findings highlight the versatility of the aurone template as a lead scaffold for the design of dual-targeting ABCG2 and ABCB1 modulators.     

Electrospun Fibers as a Solid‐State Real‐Time Zinc Ion Sensor with High Sensitivity and Cell Medium Compatibility

meso‐2,6‐Dichlorophenyltripyrrinone (TPN‐Cl₂), a probe molecule for zinc II ions, is dispersed in a polymer host. The red fluorescence peak at 620 nm appears when the molecule forms a complex with zinc at its center. TPN‐Cl₂ has a high selectivity for zinc II and tolerates many common metal ions present in the human body. The probe molecules are blended with a hydrogel polymer, poly(2‐hydroxyethyl methacrylate) (poly HEMA), with 30 wt% dimethylformamide (DMF). The fiber structure with 1 μm diameter is made by electrospinning in DMF solution of the probe and poly HEMA mixture. The fibrous film detects zinc ions with concentrations as low as 10^?6 M in real‐time both in water and in the commonly used cell culture liquid media Dulbecco's modified Eagle medium (DMEM) and fetal bovine serum (FBS), which contain many metal ions and proteins. The time‐resolution is 5 min for 10^?6 M and 1 min for 10^?5 M. This sensitivity and response speed satisfy the requirements for non‐invasive biomedical studies.     

Use of different thromboplastin reagents causes greater variability in international normalized ratio results than prolonged room temperature storage of specimens

OBJECTIVE: To determine whether a 24-hour delay in testing affects international normalized ratio (INR) reproducibility as much as using alternative thromboplastin reagents. METHODS: Specimens from warfarin-treated patients were tested at 0 hours and again at 24 hours to determine the INR, each time using RecombiPlasTin, Innovin, and C-Plus thromboplastin reagents. RESULTS: There was no clinically significant difference in INRs when a specimen was tested with the same reagent at 0 and 24 hours. However, at 0 hours, the INRs were significantly higher when a specimen was tested using C-Plus and RecombiPlasTin as compared with the result with Innovin (both P < .0001). CONCLUSIONS: A specimen can be maintained at room temperature for 24 hours without a significant change in the INR. Changing the reagent, however, can result in statistically and clinically significant differences in the INR.     

Palliative treatment of malignant esophagorespiratory fistulas with Gianturco-Z stents. A prospective clinical trial and review of the literature on covered metal stents

OBJECTIVE: Esophagorespiratory fistulas, especially in the upper third of the esophagus, are a complication of malignant esophageal tumors, which are difficult to manage. The efficacy of polyurethane-covered, self-expanding metal stents for palliation of malignant esophagorespiratory fistulas was investigated prospectively. METHODS: Eleven patients with malignant esophagorespiratory fistulas resp. perforations were treated with Gianturco-Z stents. In five patients the lesion was located in the proximal part of the esophagus. Because of the fistula all patients suffered from dysphagia even for liquids. RESULTS: No technical problems during the implantation procedure of the stents occurred. In the control radiography with water-soluble contrast media, the fistulas were completely sealed in 10 of 11 patients. Therefore the dysphagia score improved from 3.0 to 0.6. Nearly all Gianturco-Z stents (10/11) showed a sufficient expansion within 24 h after placement. Severe early or late complications were not encountered, with the exception of tumor overgrowth in one patient about 9 months after stent placement. In five patients, short term (3-6 days) retrosternal pain was observed, and one patient complained of slight foreign body sensation. By August 1997 all 11 patients had died of advanced disease, with a median survival time of 121 days (range, 22-300 days). CONCLUSIONS: Gianturco-Z stents are highly effective for palliative treatment of esophagorespiratory fistula resp. perforations and have a low complication rate. Due to the fact that this stent shows no retraction during the release, a precise positioning is possible, especially in the case of tumors and fistulas in the upper third of the esophagus. It seems that use of the Gianturco-Z stent can be considered a good therapeutic method for palliative endoscopic treatment of this high risk patient group.