Search

A set of phosphatases was evaluated for their potential to catalyze the regio‐ and stereoselective phosphorylation of alcohols using a high‐energy inorganic phosphate donor, such as di‐, tri‐ and polyphosphate. Parameters such as type and amount of phosphate donor and pH of the reaction were investigated in order to minimize the thermodynamically favored hydrolysis of the phosphate donor and the formed phosphate ester. Diols were monophosphorylated with high selectivities. This biocatalytic phosphorylation method provides selectively activated and/or protected synthetic intermediates for further chemical and/or enzymatic transformations and is applicable to a large scale (6.86 g) in a flow setup with immobilized phosphatase.

Biogenic VOC emissions are often dominated by 2-methyl-1,3-butadiene (isoprene) and 2-methyl-3-buten-2-ol (232 MBO). Here we explore the possibility to selectively distinguish these species using NO+ as a primary ion in a conventional PTR-MS equipped with an SRI unit. High purity of NO+ (>90%) as a primary ion was utilized in laboratory and field experiments using a conventional PTR-TOF-MS. Isoprene is ionized via charge transfer leading to the major product ion C5H8+ (>99%) (e.g. Spanel and Smith, 1998). 232 MBO undergoes a hydroxide ion transfer reaction resulting in the major product ion channel C5H9+ (>95%) (e.g. Amelynck et al., 2005). We show that both compounds are ionized with little fragmentation (>5%) under standard operating conditions. Typical sensitivities of 11.1 ± 0.1 (isoprene) and 12.9 ± 0.1 (232 MBO) ncps ppbv−1 were achieved, which correspond to limit of detections of 18 and 15 pptv respectively for a 10 s integration time. Sensitivities decreased at higher collisional energies. Calibration experiments showed little humidity dependence. We tested the setup at a field site in Colorado dominated by ponderosa pine, a 232 MBO emitting plant species. Our measurements confirm 232 MBO as the dominant biogenic VOC at this site, exhibiting typical average daytime concentrations between 0.2–1.4 ppbv. The method is able to detect the presence of trace levels of isoprene at this field site (90–250 ppt) without any interference from 232 MBO, which would not be feasible using H3O+ ionization chemistry, and which currently also remains a challenge for other analytical techniques (e.g. gas chromatographic methods).

To assess how early pleural and/or parenchymal abnormalities consistent with asbestos exposure could be ascertained and to identify factors associated with progression.Informed consent was obtained under an institutional review board-approved protocol. Multiple sequential chest radiographs obtained between 1955 and 2004 in 84 workers exposed to amphiboles associated with vermiculite in the town of Libby, Montana, were studied. A panel of three NIOSH B readers reviewed each worker's longitudinal chest radiograph series in reverse chronologic order and achieved a consensus reading for each radiograph. Measures of exposure were compared between workers with and those without progression of parenchymal and pleural abnormalities.Because of the way the study was designed, all subjects had pleural (n = 84) and/or parenchymal (n = 26) abnormalities on the most recent chest radiograph. Compared with other investigations that used different methods, this investigation revealed shorter latency periods (defined as the interval between date of hire and date of earliest radiographic detection) for circumscribed pleural plaque (median latency, 8.6 years) and pleural calcification (median latency, 17.5 years). Pleural abnormalities progressed in 64 workers, while parenchymal abnormalities progressed in 14. No significant differences were found with regard to measures of exposure between workers with and those without progression.The latency period for the development of pleural plaques may be shorter than previously reported. Early plaques are subtle and may not be detectable except at retrospective review.

we reviewed the imaging findings in 7 patients with idiopathic giant bullous emphysema. This is a chronic, progressive condition usually affecting young male smokers and is characterized by giant emphysematous bullae, which commonly develop in the upper lobes. Extensive paraseptal emphysema coalesces to form giant bullae, compressing the normal lung parenchyma and often displacing it centrally. These bullae occupy at least one-third of a hemithorax.Seven patients with chest radiographic evidence of a bulla or bullae occupying at least one-third of a hemithorax, who had also been examined with high-resolution computed tomography (HRCT), were included in this retrospective study. On HRCT scans, the size, location, and distribution of the bullae were documented and categorized as either subpleural or central.The HRCT scan findings in all 7 study patients included numerous bullae ranging in size from a few centimeters in diameter to giant bullae nearly filling an entire hemithorax, mimicking a pneumothorax. Five of the 7 patients had extensive upper lobe predominant bullae, 4 of the 7 patients showed severe bilateral disease with asymmetric involvement, 2 of the 7 patients demonstrated left lung predominance and whereas 1 patient showed right lung predominant disease. All of our patients had subpleural bullae, had parenchymal fibrosis, another had extensive subcutaneous emphysema, and 1 had accompanying bronchiectasis.The predominant findings on HRCT scans are extensive paraseptal emphysema coalescing into giant bullae. HRCT is helpful in confirming the diagnosis of VLS, assessing the degree of the disease, and providing information to guide treatment.

Substantial amounts of secondary organic aerosol (SOA) can be formed from isoprene epoxydiols (IEPOX), which are oxidation products of isoprene mainly under low-NO conditions. Total IEPOX-SOA, which may include SOA formed from other parallel isoprene oxidation pathways, was quantified by applying positive matrix factorization (PMF) to aerosol mass spectrometer (AMS) measurements. The IEPOX-SOA fractions of organic aerosol (OA) in multiple field studies across several continents are summarized here and show consistent patterns with the concentration of gas-phase IEPOX simulated by the GEOS-Chem chemical transport model. During the Southern Oxidant and Aerosol Study (SOAS), 78 % of PMF-resolved IEPOX-SOA is accounted by the measured IEPOX-SOA molecular tracers (2-methyltetrols, C5-Triols, and IEPOX-derived organosulfate and its dimers), making it the highest level of molecular identification of an ambient SOA component to our knowledge. An enhanced signal at C5H6O+ (m/z 82) is found in PMF-resolved IEPOX-SOA spectra. To investigate the suitability of this ion as a tracer for IEPOX-SOA, we examine fC5H6O(fC5H6O= C5H6O+/OA) across multiple field, chamber, and source data sets. A background of ~ 1.7 ± 0.1 ‰ (‰ = parts per thousand) is observed in studies strongly influenced by urban, biomass-burning, and other anthropogenic primary organic aerosol (POA). Higher background values of 3.1 ± 0.6 ‰ are found in studies strongly influenced by monoterpene emissions. The average laboratory monoterpene SOA value (5.5 ± 2.0 ‰) is 4 times lower than the average for IEPOX-SOA (22 ± 7 ‰), which leaves some room to separate both contributions to OA. Locations strongly influenced by isoprene emissions under low-NO levels had higher fC5H6O (~ 6.5 ± 2.2 ‰ on average) than other sites, consistent with the expected IEPOX-SOA formation in those studies. fC5H6O in IEPOX-SOA is always elevated (12–40 ‰) but varies substantially between locations, which is shown to reflect large variations in its detailed molecular composition. The low fC5H6O (< 3 ‰) reported in non-IEPOX-derived isoprene-SOA from chamber studies indicates that this tracer ion is specifically enhanced from IEPOX-SOA, and is not a tracer for all SOA from isoprene. We introduce a graphical diagnostic to study the presence and aging of IEPOX-SOA as a triangle plot of fCO2 vs. fC5H6O. Finally, we develop a simplified method to estimate ambient IEPOX-SOA mass concentrations, which is shown to perform well compared to the full PMF method. The uncertainty of the tracer method is up to a factor of ~ 2, if the fC5H6O of the local IEPOX-SOA is not available. When only unit mass-resolution data are available, as with the aerosol chemical speciation monitor (ACSM), all methods may perform less well because of increased interferences from other ions at m/z 82. This study clarifies the strengths and limitations of the different AMS methods for detection of IEPOX-SOA and will enable improved characterization of this OA component.

OBJECTIVE. The purpose of this study was to index the contents of the pre-MEDLINE American Journal of Roentgenology into a database that could then be accessed over the World Wide Web.CONCLUSION. The database is composed of more than 8,000 citations from the years 1914 (volume 1) to 1965 (volume 95). Using a Web browser, a user can search the database by year, volume, title word, page, or author. Results are returned sorted by year and page number in a bibliographic format. The database is accessed approximately 200 times per month.

Hemoptysis is defined as the expectoration of blood originating from the tracheobronchial tree or pulmonary parenchyma, ranging from 100 mL to 1 L in volume over a 24-hour period. This article reviews the literature on the indications and usefulness of radiologic studies for the evaluation of hemoptysis. The following recommendations are the result of evidence-based consensus by the American College of Radiology Appropriateness Criteria Expert Panel on Thoracic Radiology: (1) Initial evaluation of patients with hemoptysis should include a chest radiograph; (2) Patients at high risk for malignancy (40 y old,40 pack-year smoking history) with negative chest radiograph, computed tomography (CT) scan, and bronchoscopy can be followed with observation for the following 3 years. Radiography and CT are recommended imaging modalities for follow-up. Bronchoscopy may complement imaging during the period of observation; (3) In patients who are at high risk for malignancy and have suspicious chest radiograph findings, CT is suggested for initial evaluation; CT should also be considered in patients who are active or exsmokers, despite a negative chest radiograph; and (4) Massive hemoptysis can be effectively treated with either surgery or percutaneous embolization. Contrast-enhanced multidetector CT before embolization or surgery can define the source of hemoptysis as bronchial systemic, nonbronchial systemic, and/or pulmonary arterial. Percutaneous embolization may be used initially to halt the hemorrhage before definitive surgery.

Chronic dyspnea of pulmonary origin raises concern for chronic obstructive pulmonary disease or interstitial lung disease. A chest radiograph is recommended as the initial imaging study. When chest radiography is nonrevealing or provides no definitive diagnosis, a high-resolution chest computed tomography is indicated. The high-resolution chest computed tomography should include expiratory imaging in patients with known or suspected air trapping.

This study was designed to achieve a final modeling, validation, and standardization plan for the Wisconsin cystic fibrosis (CF) chest radiographic scoring system. Sixty chest radiographs were selected to reflect a range of severity of lung pathology in children with CF. Seven experienced volunteer raters (three radiologists and four pediatric pulmonologists) from five institutions were recruited to evaluate and score the films. Analysis of scores revealed that the subcomponents of the Wisconsin system showed considerable variation from rater to rater, but reliability assessment indicated satisfactory Cronbach's alpha coefficients (0.83-0.90) among the seven raters. It was found that an additive method of total score computation is significantly more reliable (P < 0.05) than either the original multiplicative model or the traditional Brasfield scoring system. Comparison of radiologists and pulmonologists revealed a marked, systematic difference in scoring with the former group being more conservative in interpretation of abnormalities than the pulmonologists, and some of the raters showing very limited sensitivity. Quantitative chest radiology applied to children with cystic fibrosis studied long-term in longitudinal research projects requires the careful use of sensitive scoring methods and careful selection and training of multiple raters. This is particularly important since pulmonologists and radiologists can differ systematically in interpreting/scoring abnormalities.

A simple model for surfactants in solution is used to investigate the effect of diblock spacer molecules on the structure of micellar systems. The solvent is modeled by a simple Lennard-Jones fluid and the surfactants and spacer molecules are modeled by chains of Lennard-Hones sites connected by simple harmonic bonds. The surfactant is modeled as a solventphobic tail attached to a single solventphilic head site; the spacer is modeled as a solventphobic tail attached to a chain of solventphilic head sites. Molecular dynamics simulations on large systems ({approximately}40 000 particles) are performed to investigate the properties of the model. The strength of the interaction between the solventphilic portion of the spacer and the solvent and the effect of the length of both the solventphobic and the solventphilic portions of the spacer on the structure of the micelle solution are investigated. The simulations suggest that for the spacer to keep micelles apart, the interaction between the solvent and solventphilic portion of the spacer must be fairly strong. Weak interactions between the solventphilic portion of the spacer and the solvent cause the spacer to collapse on the surface of the micelle.

Onboard hydrogen generation using compact plasmatron devices could provide important new possibilities for reducing pollution from motor vehicles, making use of alternative fuels, and increasing engine efficiency. These improvements would involve the use of the plasmatron as a very small, rugged, rapid response and highly flexible means of electrical heating of gases. Plasmatron heating could be used to facilitate conversion of a wide range of hydrocarbon fuels into hydrogen-rich gas onboard a vehicle. Use of combinations of fuels is possible through potential transformation of a variety of fuels into hydrogen-rich gas. Another advantage of use of onboard plasmatron generation of hydrogen is that it could be used only when required and could be readily turned on and off. Preliminary experimental studies of plasmatron conversion of difficult-to-use alternative fuels (biofuels), iso-octane (representative of gasoline), and diesel fuel are described. Concepts for application to trucks and other heavy duty vehicles, sport utility vehicles and automobiles are discussed.

Cyclic polarization of TiN electrodes in 6 M KOH at room temperature revealed relatively large anodic and cathodic overpotentials for water decomposition that depend on the surface structure of the material. Polished TiN electrodes also underwent a slow reaction during anodic polarization above the reversible potential for O{sub 2} evolution that involved the formation of a reaction product film. The film was uniform over the surface of the electrodes and contained hydrous potassium titanate. A corrosion product, similar in composition but less uniform in appearance, formed on TiN after 4 months under open-circuit conditions in the same solution. Results indicate that the film forms slowly by a dissolution/precipitation mechanism and that the dissolution step gives rise to an oxidation peak observed in the cyclic voltammogram during anodic polarization. Since the film forms above the reversible potential for O{sub 2} evolution and since the overvoltage for O{sub 2} evolution depends on surface structure, it is not yet clear whether the formation of the corrosion film will compete with electrolysis reactions during the charging of structurally tailored, high surface area, TiN electrodes that are under development for ultracapacitor applications.

Study objective We hypothesized that the radiographic distribution of disease is important in determining pulmonary function, with the lower lung zones of more importance than the upper lung zones. To test this hypothesis, we retrospectively studied patients with cystic fibrosis, a disease with a known proclivity for the upper lung zones. Subjects and methods Two hundred seventy-six chest radiographs obtained at 2- to 3-year intervals from 51 patients were scored by two radiologists using a 100-point visual severity scale. The distribution of disease was assessed by dividing the lungs into four equal horizontal zones and scoring each zone for the severity of disease. There were 146 concurrent chest radiographs and pulmonary function tests from which multiple linear regression was used to correlate these zonal scores with FEV 1 /FVC percent predicted. Results There was excellent interobserver agreement, intraclass correlation coefficients >0.7. The distribution of disease became predominant in the upper lung zones as the patients aged. Although the median score in the upper lung zones was nearly twice that of the lower lung zones, the lower lung zones were nearly three times (partial F ratio; 6.9 lower zone score vs 2.4 upper lung zone score) as important in determining pulmonary function. Conclusions The regional distribution of disease is important in determining pulmonary function. Sparing of the lower lung zones is important in preserving pulmonary function.

The self-assembly process provides an effective and environmentally benign method for synthesizing novel ceramic and composite materials. Three different approaches are discussed in this article: (1) self-assembly of colloidal crystals, (2) self-assembled monolayers, and (3) three-dimensional self-assembly with amphiphilic molecules. The self-assembly of colloidal crystals allows the synthesis of periodic optical devices and quantum dots from simple monodispersed particles. Self-assembled monolayers provide a molecular template to control the nucleation and growth of ceramic thin films. The emphasis of this paper will be on the self-assembly process with amphiphilic molecules, which represents the latest breakthrough in the design and synthesis of tailored nanoscale materials and composites. In the past few years, self-assembled materials have become a very active research area. This article illustrates how the basic principles of self-assembly can be applied in the synthesis of ceramic materials and discusses the role of various inter-molecular and into-particular forces.

A new mesoporous structure, silicate spherulite, has been produced in dilute surfactant and silicate solutions. The spherulites were formed from radially arranged rod-like micelles. The surfactant molecules in the rod-like micelles can be removed by heat treatment to leave a unique mesoporous material with radially arranged channels for easy access. Although the spherulite morphology has been observed in the nucleation and growth of polymeric crystals for a long time, it has not been reported in surfactant solutions. Similar to the polymeric materials, the surfactant spherulites are most likely the fingerprints of the early nucleation process in the preparation of ordered mesophase silicates.

This paper investigates the effect of hydrolysis and the formation of hydrated polycations on the colloidal stability and rheological properties of fine alumina suspensions. This is an important phenomenon in colloidal processing of advanced ceramic materials and nanocomposite materials from fine particles. The aging process and the formation of large polycations in the solution are monitored by nuclear magnetic resonance, and the aggregation rate and viscosity of the suspension are measured under similar conditions. It is observed that aging under acidic conditions increases colloidal stability against aggregation in dispersed suspensions, and reduces the viscosity in flocculated suspensions. This behavior corresponds well to the formation of large polynuclear species through hydrolysis. It is suggested that the hydrated polycations significantly modify the total interaction energy between two particles at short separation distances.

This research investigates the effect of colloidal particles on the preparation of ordered mesoporous materials (M41S). It demonstrates that colloidal silica and colloidal titania particles promote the formation of these materials. Under similar conditions no ordered structure is observed without the colloidal particles. A heterogeneous nucleation mechanism is proposed based on these observations and is supported by direct evidence from transmission electron microscopy (TEM). 15 refs., 5 figs.

More than 10 million airway branches exist in the normal human lung. Radiographic visualization is < 1% of this total. Many diseases affect the airways, each pathologic insult ultimately resulting in obstruction to airflow. Normally there is little resistance to airflow in the small airways (< 2 mm diameter); thus extensive disease may be present before it becomes clinically evident. Centrilobular emphysema is characterized by dilation and destruction of small airways, whereas bronchiolitis obliterans is characterized by concentric fibrous obliteration of small airways. High-resolution computed tomography, particularly comparison of images at full inspiration and full expiration, is the most sensitive radiographic method with which to image small airways disease.

2-Methyl-3-buten-2-ol (MBO) is an important biogenic volatile organic compound (BVOC) emitted by pine trees and a potential precursor of atmospheric secondary organic aerosol (SOA) in forested regions. In the present study, hydroxyl radical (OH)-initiated oxidation of MBO was examined in smog chambers under varied initial nitric oxide (NO) and aerosol acidity levels. Results indicate measurable SOA from MBO under low-NO conditions. Moreover, increasing aerosol acidity was found to enhance MBO SOA. Chemical characterization of laboratory-generated MBO SOA reveals that an organosulfate species (C5H12O6S, MW 200) formed and was substantially enhanced with elevated aerosol acidity. Ambient fine aerosol (PM2.5) samples collected from the BEARPEX campaign during 2007 and 2009, as well as from the BEACHON-RoMBAS campaign during 2011, were also analyzed. The MBO-derived organosulfate characterized from laboratory-generated aerosol was observed in PM2.5collected from these campaigns, demonstrating that it is a molecular tracer for MBO-initiated SOA in the atmosphere. Furthermore, mass concentrations of the MBO-derived organosulfate are well correlated with MBO mixing ratio, temperature, and acidity in the field campaigns. Importantly, this compound accounted for an average of 0.25% and as high as 1% of the total organic aerosol mass during BEARPEX 2009. An epoxide intermediate generated under low-NO conditions is tentatively proposed to produce MBO SOA. © 2012 American Chemical Society.

Advanced multiple beam equalization radiography (AMBER) and conventional chest radiography were prospectively evaluated in the detection and quantitation of alveolar (air-space) consolidation. Thirty-seven healthy volunteers underwent bronchoalveolar lavage (BAL), the retained lavage fluid serving as a model for alveolar consolidation. After BAL, the subjects underwent AMBER and conventional chest radiography. The lower lung zones on the radiographs were divided into four zones and graded for alveolar consolidation by three observers. There was no significant difference in the area under the receiver operating characteristic curve between the two techniques in the detection of lavage fluid. The grade of opacification was rated significantly higher (P.05) on conventional radiographs for three of the four lung zones examined, and the correlation between the quantity of retained lavage fluid and grade of opacity was better on conventional radiographs. Detection of lavage fluid was poor with either technique. The exposure compensation of AMBER was evident in this model of air-space disease but did not affect overall observer performance.

Workers exposed to harmful dusts such as coal often are screened for possible pneumoconiosis. A classification devised by the International Labor Office (ILO) is used for film interpretation. Film interpretation is time consuming and requires the comparison of the subject's radiograph with as many as 22 standard films and the completion of a nonintuitive form. A computer program has been written to aid in interpretation of films. This program, written in SuperCard, uses hypermedia concepts to link textual, diagrammatic, and digital images. The program includes digitized ILO radiographs, guidelines, references, and other textual and radiographic material. The program is easy to use and reduces the time required to interpret films. The concepts of how the program is constructed are emphasized so that others may devise similar program aids.

Steric stabilization of small unilamellar vesicles composed of dipalmitoyl phosphatidylglycerol (DPPG) is achieved by the incorporation of nonylphenol poly(ethylene oxide) ethers at varying mol%. Nonylphenol poly(ethylene oxide) ethers with an average of either 10.8 (NP 10 or 50 (NP 50 ethylene oxide groups are incorporated into vesicles at between 2.5 and 10 mol%. Vesicle aggregation is induced by the addition of either NaCl or CaCl 2 with the effective diameter of the vesicle dispersion measured as a function of time using photon correlation spectroscopy. The addition of between 5 and 20 mol% NP 10 to DPPG vesicles increases dispersion stability 10-fold in the presence of NaCl but only 2-fold in the presence of CaCl 2 . Dispersion stability is increased 100-fold with the addition of 10–20 mol% NP 50 in NaCl and 1000-fold in the presence of CaCl 2 . Vesicle aggregation is found to be reversible with 5 mol% added NP 50 in NaCl but only partially reversible in the presence of CaCl 2 . The hydrophobic nonylphenol moiety of NP 50 is found to be critical for imparting dispersion stability when compared to the addition of pure poly(ethylene oxide) to vesicles.