278 research outputs found

    Organics in ambient air by collection on tenax, thermal desorption,and capillary chromatography with parallel FID/ECD analysis

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    Volatile organics in ambient air were regularly collected on Tenax cartridges at high (10 ml/min) and low (5 ml/min) intake flows. These Tenax samples were analyzed by using a Tekmar Automatic Thermal Desorber and capillary GC system with parallel flame ionization (FID) and electron capture detectors (ECD). A series of quality assurance procedures has been established to improve and assure the accuracy and precision of sample collector and analysis. These procedures relate to performance of the Tekmar thermal desorber, recovery efficiency from the Tenax, and include studies on breakthrough and co-elution. The results demonstrate (1) that from ambient air data in East Central New Jersey, chlorocarbons, including chloroform, 1,1,1-trichloroethane, carbon tetrachloride, trichloroethylene and perchloroethylene, are present at lower levels than the hydrocarbons: hexane, benzene, toluene and p,m-xylene. Among the chlorocarbons, chloroform and trichloroethylene are present at very low trace levels (within 0.5 ppb) at sampling sites if compared to the other compounds; (2) the ECD is a preferred detector to accurately quantitate the chloro compounds, while hydrocarbons are bset quantitated by FID; (3) The accuracy and precision of Tenax sampling for most of the target compounds warrants its use as judged from studies of breakthrough as well as agreement between high and low flow samples; and (4) Tenax adsorbent is unable to efficiently trap light chlorocarbons such as methylchloride and dichloromethane. A statistical analysis of air data is presented based upon the above studies

    Integrative model for the selection of a new product launch strategy, based on ANP, TOPSIS and MCGP: a case study

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    New product launch strategy is a key competitive advantage for a new product development. A new product launch is a multiple criteria decision-making problem, which involves evaluating different criteria or attributes in a strategy selection process. The purpose of this paper is to develop a qualitative and quantitative approach for the selection of a new product launch strategy. The current study proposes an integrated approach, integrating analytic network process, the technique for order preference by similarity to an ideal solution and multi-choice goal programming, which can be used to determine the best launch strategy for marketing problems. The advantage of this integrated method is that it enables the consideration of both tangible (qualitative) and intangible (quantitative) criteria as well as both “more/higher is better” (e.g., benefit criteria) and “less/lower is better” (e.g., cost criteria) in the launch strategy of a new product selection problem. To show the practicality and usefulness of this method, an empirical example of a watch company is demonstrated. First published online: 03 Nov 201

    Role of Natural Wetlands in Arsenic Removal from Arsenic-Contaminated Runoff

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    This research aims to identify the role of natural wetlands in arsenic (As) removal. Phu Lek wetland in Loei Province, Thailand, was selected as the study area. Monthly samples of water (144), plant (360), and sediment (144) were collected from the wetland for 24 months. As concentration in the surface water at the wetland inlet was 0.85±0.26 mg L-1, and 0.02±0.01 mg L-1 at the wetland outlet. It was observed that the As level in water decreased significantly along its flow path, with an As removal efficiency of 98 %. As concentration in the sediment was 89.53-356.22 mg kg-1 at the inlet of wetland, but decreased gradually downstream of the water flow. Three dominant emergent plant species were observed in this wetland. As accumulation(0.02-2.37 mg kg-1) was noted in all the parts of the three plant species. As content was the highest in the rootlet(0.00-1.27 mg kg-1) compared to that in foliage (0.00-0.84 mg kg-1), leaf stalk (0.00-1.86 mg kg-1), and rhizome (0.00-2.64 mg kg-1). The level of As in the different vegetation species was in the order Diplazium esculentum > Colocasia esculenta > Lasia spinose. Further, As entrapment in the different plant plants followed the order rootlet > rhizome > foliage > leaf stalk. All the three plant species showed high bioconcentration factors, with values of 0.03-1.28, 0.02-0.93, 0.00-0.84, and 0.00-0.38 at the rootlet, rhizome, foliage, and leaf stalk, respectively, but had low translocation factors (foliage/rootlet: 0.02-0.90 and leaf stalk/rootlet: 0.00-0.44). In summary, As present in the surface water could be effectively removed by the wetland system

    Bacteremic pneumonia caused by Nocardia veterana in an HIV-infected patient

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    SummaryDisseminated Nocardia veterana infection has rarely been reported. We describe the first reported case of N. veterana bacteremic pneumonia in an HIV-infected patient. The isolate was confirmed by 16S rRNA sequencing analysis. The patient initially responded well to trimethoprim–sulfamethoxazole treatment (minimum inhibitory concentration 0.25μg/ml), but died of ventilator-associated pneumonia

    Role of the Diphosphine Chelate in Emissive, Charge-Neutral Iridium(III) Complexes

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    A class of neutral tris-bidentate Ir(III) metal complexes incorporating a diphosphine as a chelate is prepared and characterized here for the first time. Treatment of [Ir(dppb)(tht)Cl3] (1) with fppzH afforded the dichloride complexes, trans-(Cl,Cl)[Ir(dppb)(fppz)Cl2] (2) and cis-(Cl,Cl)[Ir(dppb)(fppz)Cl2] (3). The reaction of 3 with the dianionic chelate precursor bipzH2 or mepzH2, in DMF gave the complex [Ir(dppb)(fppz)(bipz)] (4) or [Ir(dppb)(fppz)(mepz)] (5), respectively. In contrast, a hydride complex [Ir(dppb)(fppz)(bipzH)H] (6) was isolated instead of 4 in protic solvent, namely: DGME. All complexes 2 - 6 are luminescent in powder forms and thin films where the dichlorides (2, 3) emit with maxima at 590-627 nm (orange) and quantum yields (Q.Y.s) up to 90% whereas the tris-bidentate (4, 5) and hydride (6) complexes emit at 455-458 nm (blue) with Q.Y.s up to 70%. Hybrid TD-DFT calculations showed considerable MLCT contribution to the orange-emitting 2 and 3 but substantial ligand-centered 3ππ* transition character in the blue-emitting 4 - 6. The dppb does not participate to these radiative transitions in 4 - 6, but it provides the rigidity and steric bulk needed to promote the luminescence by suppressing the self-quenching in the solid state. Fabrication of an OLED with dopant 5 gave a deep blue CIE chromaticity of (0.16, 0.15). Superior blue emitters, which are vital in OLED applications, may be found in other neutral Ir(III) complexes containing phosphine chelates

    The Role of Pulmonary Veins in Cancer Progression from a Computed Tomography Viewpoint

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    Background. We studied the role of pulmonary veins in cancer progression using computed tomography (CT) scans. Methods. We obtained data from 260 patients with pulmonary vein obstruction syndrome (PVOS). We used CT scans to investigate pulmonary lesions in relation to pulmonary veins. We divided the lesions into central and peripheral lesions by their anatomical location: in the lung parenchymal tissue or pulmonary vein; in the superior or inferior pulmonary vein; and by unilateral or bilateral presence in the lungs. Results. Of the 260 PVOS patients, 226 (87%) had central lesions, 231 (89%) had peripheral lesions, and 190 (75%) had mixed central and peripheral lesions. Among the 226 central lesions, 93% had lesions within the superior pulmonary vein, either bilaterally or unilaterally. Among the 231 peripheral lesions, 65% involved bilateral lungs, 70% involved lesions within the inferior pulmonary veins, and 23% had obvious metastatic extensions into the left atrium. All patients exhibited nodules within their pulmonary veins. The predeath status included respiratory failure (40%) and loss of consciousness (60%). Conclusion. CT scans play an important role in following tumor progression within pulmonary veins. Besides respiratory distress, PVOS cancer cells entering centrally can result in cardiac and cerebral events and loss of consciousness or can metastasize peripherally from the pulmonary veins to the lungs

    Oxidized-monolayer Tunneling Barrier for Strong Fermi-level Depinning in Layered InSe Transistors

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    In 2D-semiconductor-based field-effect transistors and optoelectronic devices, metal-semiconductor junctions are one of the crucial factors determining device performance. The Fermi-level (FL) pinning effect, which commonly caused by interfacial gap states, severely limits the tunability of junction characteristics, including barrier height and contact resistance. A tunneling contact scheme has been suggested to address the FL pinning issue in metal-2D-semiconductor junctions, whereas the experimental realization is still elusive. Here, we show that an oxidized-monolayer-enabled tunneling barrier can realize a pronounced FL depinning in indium selenide (InSe) transistors, exhibiting a large pinning factor of 0.5 and a highly modulated Schottky barrier height. The FL depinning can be attributed to the suppression of metal- and disorder-induced gap states as a result of the high-quality tunneling contacts. Structural characterizations indicate uniform and atomically thin surface oxidation layer inherent from nature of van der Waals materials and atomically sharp oxide-2D-semiconductor interfaces. Moreover, by effectively lowering the Schottky barrier height, we achieve an electron mobility of 2160 cm2^2/Vs and a contact barrier of 65 meV in two-terminal InSe transistors. The realization of strong FL depinning in high-mobility InSe transistors with the oxidized monolayer presents a viable strategy to exploit layered semiconductors in contact engineering for advanced electronics and optoelectronics

    Persistent surgical wound bleeding: A rare condition related to acquired hemophilia A

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    SummaryAcquired hemophilia A (AHA) is a rare condition that predisposes affected patients to a bleeding tendency, even after a trivial physical insult. We present our experience with a 45-year-old male patient who was referred to our institute because of persistent bleeding from a left forearm surgical wound after fasciotomy. He was diagnosed as having AHA. Surgical treatment in combination with recombinant activated factor VII (rFVIIa) led to a satisfactory result. Clinical awareness and multidisciplinary professional connections are necessary in the treatment of AHA. Acquired hemophilia should be considered in the differential diagnosis of patients with uncontrolled bleeding episodes
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