bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of tumor oxygenation by electron paramagnetic resonance: principles and applications
Authors: Gallez Bernard , Baudelet Christine , Jordan Bénédicte F.
Published: September 2004

This review paper attempts to provide an overview of the principles and techniques that are often termed electron paramagnetic resonance (EPR) oximetry. The paper discusses the potential of such methods and illustrates they have been successfully applied to measure oxygen tension, an essential parameter of the tumor microenvironment. To help the reader understand the motivation for carrying out these measurements, the importance of tumor hypoxia is first discussed: the basic issues of why a tumor is hypoxic, why these hypoxic microenvironments promote processes driving malignant progression and why hypoxia dramatically influences the response of tumors to cytotoxic treatments will be explained. The different methods that have been used to estimate the oxygenation in tumors will be reviewed. To introduce the basics of EPR oximetry, the specificity of in vivo EPR will be discussed by comparing this technique with NMR and MRI. The different types of paramagnetic oxygen sensors will be presented, as well as the methods for recording the information (EPR spectroscopy, EPR imaging, dynamic nuclear polarization). Several applications of EPR for characterizing tumor oxygenation will be illustrated, with a special emphasis on pharmacological interventions that modulate the tumor microenvironment. Finally, the challenges for transposing the method into the clinic will also be discussed. Copyright © 2004 John Wiley & Sons, Ltd.
Protective mechanisms of Pycnogenol® in ethanol‐insulted cerebellar granule cells
Authors: Siler‐Marsiglio Kendra I. , Paiva Michael , Madorsky Irina , Serrano Yahaira , Neeley Andy , Heaton Marieta B.
Published: September 2004

Pycnogenol® (PYC), a patented combination of bioflavonoids extracted from the bark of French maritime pine (Pinus maritima), inhibits apoptosis and necrosis of developing neurons exposed acutely to ethanol (EtOH). The present study shows that the protective mechanisms of PYC in EtOH‐exposed postnatal day 9 cerebellar granule cells (P9 CGCs) include (1) reduction of reactive oxygen species (ROS) production; (2) counteraction of suppressed copper/zinc superoxide dismutase (Cu/Zn SOD) and glutathione peroxidase/reductase (GSH‐Px/GSSG‐R) system activities; (3) upregulation of Cu/Zn SOD protein expression; (4) mitigation of the EtOH‐mediated exacerbation of catalase (CAT) activity; and, (5) specific binding and inhibition of active caspase‐3. These results indicate that the mechanisms by which PYC antagonizes EtOH‐induced oxidative stress include oxidant scavenging and modulation of endogenous, cellular proteins. Using findings from the present and previous studies, a model delineating the mechanisms of EtOH effects on the system of antioxidant enzymes in developing CGCs is presented. © 2004 Wiley Periodicals, Inc. J Neurobiol, 2004
Prolonged moderate elevation of corticosterone does not affect hippocampal anatomy or cell proliferation rates in mountain chickadees (Poecile gambeli)
Authors: Pravosudov Vladimir V. , Omanska Alicja
Published: September 2004

Chronic stress and corresponding chronic elevations of glucocorticoid hormones have been widely assumed to have deleterious effects on brain anatomy and functions such as learning and memory. In particular, it has been suggested that chronic elevations of glucocorticoid hormones result in death of hippocampal neurons and in reduced rates of hippocampal neurogenesis. It is not clear, however, if any increase in glucocorticoid levels has negative effects on hippocampal anatomy as many animals regularly maintain moderately elevated levels of glucocrticoids over long periods of time under natural energetically demanding conditions. We used unbiased stereological methods to investigate whether mountain chickadees (Poecile gambeli) implanted for 49 days with continuous time‐release corticosterone pellets, designed to approximately double the baseline corticosterone levels, differed from placebo‐implanted chickadees in their hippocampal anatomy and cell proliferation rates. We found no significant differences between corticosterone and placebo‐implanted birds in either telencephalon volume, volume of the hippocampal formation, or the total number of hippocampal neurons. Cell proliferation rates, measured as the total number of BrdU‐labeled cells in the ventricular zone adjacent either to the hippocampus or to the mesopallium, were also not significantly different between corticosterone and placebo‐implanted chickadees. Our results suggest that prolonged moderate elevation of corticosterone might not provide the suggested deleterious effects on hippocampal anatomy and neurogenesis in food‐caching birds and, as we have shown previously, it actually enhances spatial memory. © 2004 Wiley Periodicals, Inc. J Neurobiol, 2005
Distinct temporal genetic signatures of neurogenic and gliogenic cues in cortical stem cell cultures
Authors: Sauvageot Claire , Dahia Patricia L. , Lipan Ovidiu , Park John K. , Chang Mi‐Sook , Alberta John A. , Stiles Charles D.
Published: September 2004

Cortical progenitor cells from rat embryos give rise to neurons or glia following exposure to platelet derived growth factor (PDGF) or ciliary neurotrophic factor (CNTF), respectively. Both growth factors impart their developmental cues quickly through a transcription‐dependent mechanism. Do the alternate developmental responses to PDGF and CNTF reflect induction of qualitatively distinct genes? Alternatively, do the same genes respond to each growth factor, but with quantitatively distinct kinetics? Using differential library screening and custom cDNA microarrays we show that a common set of genes responds to either growth factor. However, quantitative differences in the onset and duration of gene induction equate to the expression of factor‐specific gene signatures. Multitissue cluster analysis also reveals tissue‐specific gene signatures that may play important roles in the developing brain. © 2004 Wiley Periodicals, Inc. J Neurobiol, 2005
The endogenous cannabinoid system and its role in nociceptive behavior
Authors: Cravatt Benjamin F. , Lichtman Aron H.
Published: September 2004

The analgesic properties of exogenous cannabinoids have been recognized for many years and suggest a regulatory role for the endogenous cannabinoid (“endocannabinoid”) system in mammalian nociceptive pathways. The endocannabinoid system includes: (1) at least two families of lipid signaling molecules, the N‐acyl ethanolamines (e.g., anandamide) and the monoacylglycerols (e.g., 2‐arachidonoyl glycerol); (2) multiple enzymes involved in the biosynthesis and degradation of these lipids, including the integral membrane enzyme fatty acid amide hydrolase; and (3) two G‐protein coupled receptors, CB1 and CB2, which are primarily localized to the nervous system and immune system, respectively. Here, we review recent genetic, behavioral, and pharmacological studies that have tested the function of the endocannabinoid system in pain sensation. Collectively, these investigations support a role for endocannabinoids in modulating behavioral responses to acute, inflammatory, and neuropathic pain stimuli. © 2004 Wiley Periodicals, Inc. J Neurobiol 61: 149–160, 2004
Antinociceptive and nociceptive actions of opioids
Authors: Ossipov Michael H. , Lai Josephine , King Tamara , Vanderah Todd W. , Malan T. Philip , Hruby Victor J. , Porreca Frank
Published: September 2004

Although the opioids are the principal treatment options for moderate to severe pain, their use is also associated with the development of tolerance, defined as the progressive need for higher doses to achieve a constant analgesic effect. The mechanisms which underlie this phenomenon remain unclear. Recent studies revealed that cholecystokinin (CCK) is upregulated in the rostral ventromedial medulla (RVM) during persistent opioid exposure. CCK is both antiopioid and pronociceptive, and activates descending pain facilitation mechanisms from the RVM enhancing nociceptive transmission at the spinal cord and promoting hyperalgesia. The neuroplastic changes elicited by opioid exposure reflect adaptive changes to promote increased pain transmission and consequent diminished antinociception (i.e., tolerance). © 2004 Wiley Periodicals, Inc. J Neurobiol 61: 126–148, 2004
Voltage‐gated sodium channels and pain pathways
Authors: Wood John N. , Boorman James P. , Okuse Kenji , Baker Mark D.
Published: September 2004

Acute, inflammatory, and neuropathic pain can all be attenuated or abolished by local treatment with sodium channel blockers such as lidocaine. The peripheral input that drives pain perception thus depends on the presence of functional voltage‐gated sodium channels. Remarkably, two voltage‐gated sodium channel genes (Nav1.8 and Nav1.9) are expressed selectively in damage‐sensing peripheral neurons, while a third channel (Nav1.7) is found predominantly in sensory and sympathetic neurons. An embryonic channel (Nav1.3) is also upregulated in damaged peripheral nerves and associated with increased electrical excitability in neuropathic pain states. A combination of antisense and knock‐out studies support a specialized role for these sodium channels in pain pathways, and pharmacological studies with conotoxins suggest that isotype‐specific antagonists should be feasible. Taken together, these data suggest that isotype‐specific sodium channel blockers could be useful analgesics. © 2004 Wiley Periodicals, Inc. J Neurobiol 61: 55–71, 2004
Volumetric locking in natural neighbour Galerkin methods
Authors: González D. , Cueto E. , Doblaré M.
Published: September 2004

The behaviour of natural neighbour Galerkin mixed approximation is described at the incompressible limit. Traditional natural elements based on the Sibson mixed interpolation do not verify the LBB (or inf–sup) condition. Here, a study of the possible benefits of enriching the interpolation is considered using the partition of unity paradigm. Different enrichments were tested leading to different reproducing properties. Results concerning the numerical verification of the inf–sup tests are addressed. Also the convenience of using different approximations developed in this work is analysed. Enrichment with the polynomial field {1, xy} seems to verify the LBB condition. Its behaviour has proven to be very similar to the MINI Finite Element, widely used in the literature. Examples proving these results are provided. Copyright © 2004 John Wiley & Sons, Ltd.
Academic stress, immunological reaction, and academic performance among students of nursing and physiotherapy
Authors: Sarid Orly , Anson Ofra , Yaari Arieh , Margalith Miriam
Published: September 2004

The associations among health status, health behavior, and changes in human cytomegalovirus (HCMV) specific salivary antibodies during academic stress were investigated in relation to academic achievement among nursing and physiotherapy students. Fifty‐four first year students donated saliva samples and completed a pencil and paper questionnaire before (t1), during two term examinations (t2 and t3), and after grades were posted (t4). An increase in the level of specific salivary HCMV IgG and IgA antibodies from t1 to t2, and a decrease from t2 to t4 were related to academic success. Health status and health behavior remained fairly stable during the stress period. The results are congruent with the inverted U‐shape model of stress and learning suggested by Yerkes & Dodson (1908). © 2004 Wiley Periodicals, Inc. Res Nurs Health 27:370–377, 2004
A thematic analysis of Korean family caregivers' experiences in making the decision to place a family member with dementia in a long‐term care facility
Authors: Park Myonghwa , Butcher Howard Karl , Maas Meridean L.
Published: September 2004

The purpose of this study was to provide an in‐depth description of 19 Korean family caregivers' experiences in making the decision to place a family member with dementia in a Korean long‐term care facility. A total of 656 themes (descriptive statements) were identified and synthesized into 17 topics using Luborsky's method for thematic analysis. The topics were synthesized into four patterns: (a) feeling exhausted; (b) deep sorrow; (c) fractured relationships; and (d) apprehension. The findings enhance the capacity of health care professionals and the public to understand more fully, how caregiving experiences differ by cultural context. The findings contribute to understanding family caregiving experiences in a country in transition from a traditional society based on Confucianism to a Westernized society. © 2004 Wiley Periodicals, Inc. Res Nurs Health 27:345–356, 2004
Assessment of fetal lung development by quantitative ultrasonic tissue characterization: a methodical study
Authors: Tekesin Ismail , Anderer Georgia , Hellmeyer Lars , Stein Werner , Kühnert Maritta , Schmidt Stephan
Published: September 2004

Objectives

This study was performed to evaluate the quantitative ultrasonic tissue characterization of the normal fetal lung development by using acoustic raw data captured after preprocessing.

Methods

One hundred and sixty‐two patients with completed gestational ages between 22 and 37 weeks were enrolled in this study. Longitudinal and transverse sections of the fetal thorax and upper abdomen were imaged. A region of interest of constant size was defined and the tissue‐specific gray scale was determined by using an interactive software.

Results

A total of 162 patients met the inclusion criteria. The echogenicity of the fetal lung showed a particular changing pattern during pregnancy: the mean gray value of the fetal lung (MGV) is almost the same as the MGV of the fetal liver at 22 and 23 weeks, decreases between 22 and 31 weeks and increases between 31 and 37 weeks. The MGV of the fetal liver decreases significantly from 24 weeks to 31 weeks and increases significantly again toward 37 weeks. We stated that the MGV of the lung is smaller than the MGV of the liver during 31 weeks of gestation and the relation reverses in late gestation. At term, the MGV of the liver is greater than the MGV of the lung. The lung‐to‐liver ratio is <1 between 24 and 29 weeks and >1 between 30 and 35 weeks.

Conclusion

The echogenicity of the fetal lung showed a particular changing pattern during pregnancy, which corresponds to morphologic changes of the fetal lung development. Copyright © 2004 John Wiley & Sons, Ltd.
Antimicrobials for the treatment of urinary tract infection in pregnancy: practices in southern India
Authors: Mathai Elizabeth , Thomas Raja John , Chandy Sujith , Mathai Matthews , Bergstrom Staffan
Published: September 2004

Purpose

Although urinary tract infection (UTI) in pregnancy is a common medical problem, very little is known about the susceptibility patterns of bacteria causing UTI and the prescription practices for UTI in pregnancy in low‐income countries. Studies were, therefore, carried out in southern India to document the susceptibility patterns and to compare these with prescription practices.

Methods

Data on susceptibility patterns of bacteria isolated in significant counts from urine of pregnant women suspected to have urinary infection were collected. Prescribing patterns for these infections were ascertained using a questionnaire.

Results

About 90% of E. coli causing UTI is still susceptible to nitrofurantoin, a relatively inexpensive and safe drug. However, less than 25% of doctors used it for treatment of cystitis. Cephalosporins were most commonly used in hospital practice for the treatment of UTI. Amoxycillin was being used widely to treat UTI in pregnancy in spite of high prevalence of resistance. There were wide variations in the duration of therapy and use of prophylaxis.

Conclusions

Our findings indicate an urgent need for proper guidelines, dissemination of information to practitioners and supervision of antimicrobial usage in low income countries like India. Irrational and unnecessary drug use can be expensive and harmful. Copyright © 2004 John Wiley & Sons, Ltd.
Comparative proteome analysis of cellular proteins extracted from highly virulent Francisella tularensis ssp. tularensis and less virulent F. tularensis ssp. holarctica and F. tularensis ssp. mediaasiatica
Authors: Hubálek Martin , Hernychová Lenka , Brychta Martin , Lenčo Juraj , Zechovská Jana , Stulík Jiří
Published: September 2004

Francisella tularensis is the causative agent of the zoonotic disease tularemia. Four subspecies of this pathogen, namely ssp. tularensis, mediaasiatica, holarctica, and novicida are spread throughout the northern hemisphere. Although there are marked variations in their virulence to mammals, the subspecies are difficult to identify as they are closely genetically related. We carried out the comparative proteome analysis of cellular extracts from isolates representing the highly virulent subspecies tularensis, and the less virulent subspecies mediaasiatica and holarctica in order to identify new diagnostic markers and putative factors of virulence. We identified 27 protein spots that were either specifically present or at significantly higher abundance in ssp. tularensis strains, 22 proteins in ssp. mediaasiatica strains, and 26 proteins in ssp. holarctica strains. Subspecies tularensis‐specific proteins might represent putative virulence factors. Of 27 identified tularensis‐specific spots 17 represented charge and mass variants of proteins occurring in other subspecies, 7 spots were found to be present at higher abundance, and 3 spots were specifically present in tularensis strains. Amongst them, PilP protein, as a component neccessary for the biogenesis of the type IV pilus, virulence and adhesion factor for many human pathogen, was identified. Furthermore, the identification of additional 27 proteins common for ssp. tularensis and mediaasiatica, and 19 proteins shared by ssp. mediaasiatica and holarctica documented apparent closer genetic similarity between ssp. tularensis and mediaasiatica.
Elements for the construction of molecular devices: template effects and self‐assembly
Authors: Schalley Christoph A.
Published: September 2004

Four elements which may prove useful for the construction of molecular shuttles and other devices at the molecular level are discussed. (i) A novel anion‐mediated template effect allows functionality to be introduced into the axle center pieces of rotaxanes so that molecular motions of the axle and wheel can be controlled by external stimuli. (ii) The deslipping kinetics of rotaxanes provide valuable insight into large changes of the deslipping rate caused by minimal structural changes. These effects, once understood, could be exploited for an optimization of the functionality of molecular devices. (iii) A wheel with an exocyclic metal coordination site provides access to self‐assembled species that combine more than one macrocycle or rotaxane. This is a step towards a controlled growth of more complex species and in future may help to reduce the synthetic efforts needed for the generation of large and complex systems through self‐assembly rather than covalent synthesis. (iv) In particular, for self‐assembled systems with their often high degree of symmetry, mass spectrometry provides a valuable tool for the determination of their sizes. Beyond characterization, mass spectrometry provides an insight into structural details and the intrinsic reactivity of supramolecular species and thus can be expected to play an increasingly important role in the examination of molecular devices. Copyright © 2004 John Wiley & Sons, Ltd.
Cases of pronounced extended π,n‐participation in solvolysis of tert‐butyl and benzyl chloride derivatives
Authors: Jurić Sandra , Kronja Olga
Published: September 2004

Solvolysis rates of chlorides that share the same side‐chain comprising two neighboring groups [tertiary chloride 10, 2‐chloro‐2,6‐dimethyl‐9‐methoxy‐(6E)‐nonene, and benzyl chlorides 11, 1‐chloro‐1‐aryl‐5‐methyl‐8‐methoxy‐(5E)‐octene, with various phenyl substituents (Y = p‐OCH3, p‐CH3, H, p‐Br and m‐Br)], were measured in 80% (v/v) aqueous ethanol. Both the tertiary substrate 10 and the benzyl substrates 11 solvolyze with smaller entropy and enthalpy of activation than the corresponding reference analogs with one neighboring group, 6 and 8, respectively (ΔΔH≠ = −34 ± 6 kJ mol−1, ΔΔS≠ = −122 ± 19 J K−1 mol−1 with 10; ΔΔH≠ = −33 ± 6 kJ mol−1, ΔΔS≠ = −95 ± 17 J K−1 mol−1 with 11), indicating that in addition to the double bond, the methoxy group also participates in the rate‐determining step. Chloride 10 has a significantly reduced secondary β‐deuterium kinetic isotope effect (kH/kD = 1.07 ± 0.01 in 80E; kH/kD = 1.05 ± 0.1 in 97T) in comparison with the typical value for the tertiary chlorides (kH/kD = 1.80), as a consequence of the less positive charge on the reaction center in the transition state. The slope of the Hammett plot ρ+ value obtained with the series of 11 is considerably smaller than that obtained with the reference chlorides 8‐Y (ρ+ = −1.29 ± 0.11 vs −3.93 ± 0.10), confirming that benzyl substrates also solvolyze with extended π,n‐participation. On both types of substrates, 10 and 11, the kinetic parameters indicate that very pronounced assistance of both neighboring groups occurs in the rate‐determining step. Copyright © 2004 John Wiley & Sons, Ltd.
Controlled polymerizations of 2‐(dialkylamino)ethyl methacrylates and their block copolymers in protic solvents at ambient temperature via ATRP
Authors: Mao Baowei , Gan Leong‐Huat , Gan Yik‐Yuen , Li Xiaoshi , Ravi Palaniswamy , Tam Kam‐Chiu
Published: September 2004

Very well‐controlled polymerizations of 2‐(dimethylamino)ethyl methacrylate (DMAEMA) and 2‐(diethylamino)ethyl methacrylate (DEAEMA) in aqueous and methanolic solutions via atom transfer radical polymerization (ATRP) at ambient temperature were demonstrated. Poly(DMAEMA) and poly(DEAEMA) of low polydispersity index (PDI) of ∼1.07 were obtained using the p‐toluenesulfonyl chloride/CuCl/1,1,4,7,10,10‐hexamethyl‐triethylenetetramine (p‐TsCl/CuCl/HMTETA) system. Excellent control of polymerization was achieved even in pure methanol. This is in contrast with the very poor control of DMAEMA ATRP in methanol reported previously using a different intiator/catalyst/ligand system. The initiator p‐TsCl underwent hydrolysis reaction in aqueous methanolic solutions with a second‐order rate constant of 6.1 × 10−4 dm3 mol−1 s−1 at 25 °C. Both poly(DMAEMA) and poly(DEAEMA) retained almost full chlorine‐functionization at the chain ends. Well‐defined block copolymers of DEAEMA and DMAEMA were successfully obtained by starting with either macroinitiators of DEAEMA or DMAEMA. Other well‐defined diblock copolymers could be prepared using these macroinitiators. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5161–5169, 2004
Synthesis and vesicular polymerization of novel counter‐ion polymerizable/crosslinkable surfactants
Authors: Paul Geeta Kheter , Indi S. S. , Ramakrishnan S.
Published: September 2004

Two novel two‐tail surfactants, dicetyldimethylammonium 4‐vinyl benzoate (DDVB) and dicetyldimethylammonium 3,5‐divinyl benzoate (DDDB), were synthesized by neutralizing the corresponding quaternary ammonium hydroxide with the appropriate benzoic acid. As expected, these surfactants formed both homo and mixed‐vesicles, which were readily polymerized with a suitable radical photo‐initiator. The polymerization process was followed by UV–vis spectroscopy and also reconfirmed by NMR and IR spectroscopy. Polymerization of vesicles prepared from DDVB, unlike the more commonly polymerized vesicles, in which the polymerizable group forms an integral part of the surfactant, leads to the formation of a linear polyelectrolyte chain that is only electrostatically bound to the lipid bilayer. On the other hand, polymerization of DDDB vesicles leads to the formation of a crosslinked shell (or net) that encases the vesicle bilayer. Such counterion crosslinked vesicles were shown to be resistant to destabilization both by lysis as well as in the presence of a fairly high volume fraction of an organic solvent, such as ethanol. However, although the simple polymerized (linearly) vesicles, formed from DDVB, exhibit enhanced stability toward lysis when compared to their unpolymerized counterparts, they are readily destabilized in the presence of ethanol, leading to precipitation. This sharp contrast in the behavior of linearly polymerized and crosslinked systems suggests that crosslinking is essential to arrest conformational reorganization of the polyelectrolyte chains induced by a change in the solvent medium, which in turn leads to precipitation. Such counterion crosslinked vesicular systems also have an added advantage; they may retain the fluidityof the lipid bilayer while at the same time possess enhanced stability. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5271–5283, 2004
Thermal expansion coefficient and bulk modulus of polyethylene closed‐cell foams
Authors: Almanza O. , Masso‐Moreu Y. , Mills N. J. , Rodríguez‐Pérez M. A.
Published: September 2004

A regular Kelvin foam model was used to predict the linear thermal expansion coefficient and bulk modulus of crosslinked, closed‐cell, low‐density polyethylene (LDPE) foams from the polymer and gas properties. The materials used for the experimental measurements were crosslinked, had a uniform cell size, and were nearly isotropic. Young's modulus of biaxially oriented polyethylene was used for modeling the cell faces. The model underestimated the foam linear thermal expansion coefficient because it assumed that the cell faces were flat. However, scanning electron microscopy showed that some cell faces were crumpled as a result of foam processing. The measured bulk modulus, which was considerably smaller than the theoretical value, was used to estimate the linear thermal expansion coefficient of the LDPE foams. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3741–3749, 2004
A Time‐ and Angle‐Resolved X‐Ray Photoelectron Spectroscopy Study of Polystyrene Exposed to a Helium Plasma
Authors: Paynter Royston W. , Ménard Marc , Benalia Hadjira
Published: September 2004

Summary: Angle‐resolved X‐ray photoelectron spectroscopy (ARXPS) measurements were carried out, using Al Kα and Mg Kα radiation alternately, on a polystyrene sample that had been exposed to a helium plasma. It was observed that oxygen was introduced into the sample surface by the plasma treatment, and that some of it was lost over a period of 5 h under X‐ray irradiation in the vacuum of the spectrometer. The ARXPS data sets were corrected for the time displacement between consecutive measurements at different photoemission angles, and fitted with trapezoidal model depth profiles in order to extract simple oxygen concentration depth profiles, consistent with the data, as a function of time. The depth profiles were found to evolve in a consistent manner, indicating some loss of average concentration and especially thickness in the oxygen profile. In comparison with previously published results obtained using a helium/oxygen plasma, the oxygen loss was less severe. The results are also interpreted in terms of a model supposing the desorption of a highly oxidized oligomer layer created during the plasma exposure.

Evolution of the apparent concentration of oxygen with Al Kα radiation as a function of irradiation time and photoemission angle. Symbols: ARXPS data; lines: splines drawn through points calculated from fitted depth profiles.

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Evolution of the apparent concentration of oxygen with Al Kα radiation as a function of irradiation time and photoemission angle. Symbols: ARXPS data; lines: splines drawn through points calculated from fitted depth profiles.
Nonthermal Plasma Processing for Air‐Pollution Control: A Historical Review, Current Issues, and Future Prospects
Authors: Kim Hyun‐Ha
Published: September 2004

Summary: This review describes the historical development, current status, and future prospects for nonthermal plasma (NTP) technology and its application as an air‐pollution control. In particular, this review focuses on the cutting‐edge technology of hybrid NTP, where it is combined with other methods such as wet processing, the use of adsorbents, and catalysis. Historical landmarks in the development of NTP technology and the current status of large‐scale applications are discussed. The general characteristics of the combined system of NTP with catalysts are described in the context of the decomposition of NOx and benzene.

Comparison of different NTP reactors for 200 ppm benzene decomposition (water vapor 0.5 vol.‐%).

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Comparison of different NTP reactors for 200 ppm benzene decomposition (water vapor 0.5 vol.‐%).
Small‐angle Scattering Studies of Adsorption and of Capillary Condensation in Porous Solids
Authors: Hoinkis Ernst
Published: September 2004

Small‐angle scattering (SAS) studies are reviewed of adsorption and capillary condensation of water, hydrocarbons and halogenated hydrocarbons near room temperature, and of nitrogen at 78 K in some mesoporous solids, mainly silicas. The theory needed for the interpretation of SAS data is briefly covered. Calculations of the scattered intensity I(q) for a model porous medium show that I(q) depends markedly on the film thickness t. Adsorption and capillary condensation of nitrogen at 78 K in mesoporous silicas was studied by use of in situ SANS, and t as function of the relative pressure P/Ps was estimated. Adsorption of N2 in defects within the silica skeleton at P/Ps<0.1 lead to a significant increase in I(q). Isolated vapor bubbles in capillary condensed nitrogen in a Gelsil® appeared on adsorption near saturation of the pore system. The kinetics of capillary condensation and of drainage were followed. Power law scattering at low q indicated the formation of ramified clusters of voids on drainage of liquid nitrogen from the xerogel Gelsil®. Similar clusters were observed on drainage of water from Vycor® glass. Provided the clusters indicate a percolation process, the desorption branch should not be used for the estimation of a pore size distribution for materials with networked pores. The adsorptive smoothing by benzene was observed of a rough interface in a controlled pore glass.
Comparing the Basic Phenomena Involved in Three Methods of Pore‐size Characterization: Gas Adsorption, Liquid Intrusion and Thermoporometry
Authors: Denoyel Renaud , Llewellyn Philip , Beurroies Isabelle , Rouquerol Jean , Rouquerol Françoise , Luciani Laurent
Published: September 2004

Gas adsorption at 77 K is probably the most widely used method to characterize mesoporous adsorbents via capillary condensation. Mercury intrusion is also commonly used for the characterization of such materials with the possibility to extend the pore width distribution measurement to the macropore range. More recently water intrusion was proposed to study hydrophobic porous solids. Thermoporometry is a further characterization method, now based on the study of the solid/liquid transition. We can consider that all these methods rely on the modification of the phase diagram of a pure substance under the effect of confinement. For each of them, the equations and models derived are based either on classical thermodynamics or on statistical approaches. In most cases, the derivation of the pore width distribution is carried out with the assumption that the porous system is made up of non‐connected cylinders, whereas the actual complexity of the structure is derived from the hysteresis shape. Our aim here is to compare the four approaches above (gas adsorption, mercury intrusion, water intrusion, thermoporometry) on samples giving rise, in their gas adsorption isotherms, to the typical hysteresis loops of the IUPAC classification. Our comparison is in great part carried out after the shape of the hysteresis loops obtained with the various methods and after the information it brings on the mechanism of replacement of a phase by the other within the porous system.
Quantitative air‐trapping analysis in children with mild cystic fibrosis lung disease
Authors: Bonnel Anne‐Sophie , Song Samuel Moon‐Ho , Kesavarju Krishnaveni , Newaskar Manisha , Paxton Craig J. , Bloch Daniel A. , Moss Richard B. , Robinson Terry E.
Published: September 2004

The purpose of this study was to compare quantitative computed tomography air trapping (AT) and pulmonary function measurements between subjects with mild cystic fibrosis lung disease (MCF; forced expiratory volume in 1 sec (FEV1) > 70% predicted) and normal age‐matched controls. Quantitative AT measurements at different levels of expiration were evaluated. Ten subjects from the MCF group and 10 normal subjects underwent inspiratory and expiratory spirometer‐triggered chest high‐resolution computed tomography (HRCT) and pulmonary function tests. Six matched CT images were obtained at full inflation and at a lung volume near residual volume (nRV). Quantitative measurements of AT were determined by evaluating expiratory CT lung density and by the percent of segmented lung which demonstrated AT on expiratory scans. Percent AT was evaluated for all lung slices combined (global AT), and also by regional assessment. Additional comparisons of lung density and percent air trapping were made in 10 CF subjects with three matched axial HRCT images at lung volumes corresponding to full inflation, near functional residual capacity (nFRC), and nRV. All measurements of expiratory lung density in CF subjects were significantly lower and % AT significantly higher than normal controls. Significant correlations for all subjects were observed between % global AT and RV/TLC as well as forced expiratory flow between 25–75% of forced vital capacity (FEF25–75) % predicted. Pulmonary density measurements and % AT better discriminated differences between groups than PFTs. Measurements made on expiratory scans near FRC showed significantly higher values for AT than those made near RV. © 2004 Wiley‐Liss, Inc.
Polymorphisms in the 5α reductase type 2 gene and urologic measures of BPH
Authors: Roberts Rosebud O. , Bergstralh Erik J. , Farmer Sara A. , Jacobson Debra J. , McGree Michaela E. , Hebbring Scott J. , Cunningham Julie M. , Anderson Sarah A. , Thibodeau Stephen N. , Lieber Michael M. , Jacobsen Steven J.
Published: September 2004

BACKGROUND

The objective of the study was to examine associations between SRD5A2 polymorphisms and measures of benign prostatic hyperplasia (BPH).

METHODS

Participants were 510 Caucasian men (median age 60 years), randomly selected from the Olmsted County, MN community to participate in a longitudinal study of BPH. From 1990 through 2000, biennial measurements of lower urinary tract symptom severity (assessed from the American Urological Association Symptom Index, AUASI), peak urinary flow rates (Qmax), and prostate volume were made. Genotyping of SRD5A2 V89L, A49T, and TA repeat polymorphisms were performed.

RESULTS

Compared with the VV genotype, the LL genotype was associated with an enlarged prostate (Hazard ratio (HR) = 1.62, 95% confidence interval (CI) = 1.06, 2.43) but not with AUASI, Qmax, or PSA. The A49T and TA repeat polymorphisms were not associated with BPH. When the LL/VL, AT/TT, and TA(0)/TA(0) genotypes were considered high risk, the number of high risk genotypes increased with increasing prostate volume (32.3, 30.7, 34.1, and 38.7, respectively, P for trend = 0.04).

CONCLUSIONS

These findings do not demonstrate consistent associations between SRD5A2 genotypes and BPH. However, they suggest that the associations of V89L polymorphisms and prostate volume should be investigated further. © 2004 Wiley‐Liss, Inc.
Spatial and temporal distribution of imidacloprid and thiamethoxam in citrus and impact on Homalodisca coagulata populations
Authors: Castle Steven J , Byrne Frank J , Bi Jian L , Toscano Nick C
Published: September 2004

Titers of two systemic neonicotinoid insecticides in citrus trees were measured in conjunction with conventional evaluations of their impact on glassy‐winged sharpshooter (Homalodisca coagulata (Say); GWSS) populations. Xylem fluid samples were collected at regular intervals and from multiple locations within field‐grown citrus trees to determine imidacloprid and thiamethoxam concentrations using commercial ELISA kits. Uptake profiles varied considerably with peak mean titers of imidacloprid occurring 6–8 weeks after application compared with 2 weeks for thiamethoxam. The persistence of each compound also varied as near‐peak levels of imidacloprid were sustained for another 6–10 weeks before gradually declining. In contrast, thiamethoxam titers declined more rapidly after the initial peak, possibly reflecting an application rate only one‐quarter of that used for imidacloprid. Within‐tree distributions were more similar for the two compounds, with no significant effect due to height of the sample (upper or lower half) or to the quadrant location within the tree, with the exception of one quadrant in the thiamethoxam‐treated trees. Substantial reductions in GWSS nymphs and adults were observed in imidacloprid‐treated trees during the 2001 trial and were sustained for 4–5 months after treatment. Treatment effects on nymphs were not as well pronounced in the 2002 trial, when overall GWSS infestations were much reduced from the previous year. However, consistently lower adult infestations were still observed in 2002 for both treatments compared with untreated trees. Information on the spatial and temporal profiles in citrus trees was obtained for both compounds to complement field impact data and improve understanding of their pest management potential. Copyright © 2004 Society of Chemical Industry
Structural analysis of thick GaN films grown by hydride vapour phase epitaxy
Authors: Ruterana Pierre , Chen Jun , Nouet Gérard , Lei Benliang , Ye Haohua , Yu Guanghui , Qi Ming , Li Aizhen
Published: September 2004

Thick GaN films were deposited on sapphire substrate by hydride vapour phase epitaxy (HVPE) in two steps at 1050 °C. The substrate was first nitridated for different times between 1 and 10 minutes before deposition of a 12 μm thick layer. X‐ray rocking curves show a minimum for 5 and 7 minutes of nitridation. The shift of the photoluminescence peak (PL) at room temperature from 3.328 to 3.405 eV is consistent with the evolution of the microstructure which is characterised by non‐compact layers for the shortest times of nitridation. The nitridation of the sapphire surface results in the formation of a damaged layer with a thickness varying with the nitridation times. In this interfacial area, flat interfaces are present, but AlN nanocrystals may be observed as well as an amorphous zones containing Al, O and N. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Raman spectroscopy with UV excitation on untwinned single crystals of YBa2Cu3O7–δ
Authors: Bahrs S. , Reich S. , Zwick A. , Goñi A. R. , Bacsa W. , Nieva G. , Thomsen C.
Published: September 2004

Recent reflectance anisotropy studies on the material showed a photobleaching effect in the in‐plane components of the dielectric function around 2.2 and 4.1 eV [1]. We present Raman spectra of oxygen deficient YBa2Cu3O7–δ detwinned single crystals taken with laser excitation of 3.7 eV, close to the UV feature in the dielectric function, in search for a signal from the defect‐induced Raman modes. While two groups of defect‐induced mode at 230 cm–1 and 600 cm–1 behave very similar at the 2.2 eV resonance, we find clear differences for UV excitation. A peak at 600 cm–1 is identified as a copper‐oxygen‐chain related, defect‐induced modes by its Raman selection rules. While this mode is enhanced beyond the strength of the Raman‐allowed modes, the group at 230 cm–1 is absent. Low temperature experiments showed no change of the peak height under illumination, though the peaks are known to photobleach in the visible. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Theoretical study of hydrogen bonds between acetylene and selected proton donor systems
Authors: Bende A. , Vibók Á. , Halász G. J. , Suhai S.
Published: September 2004

The equilibrium structures, the binding energies, and the second‐order energy components of a series of hydrogen‐bonded complexes involving acetylene are studied. The strength of the binding energy of the selected systems (HF … HCCH, HCl … HCCH, HCN … HCCH, and HCCH … HCCH) was different, ranging from a very weak interaction to a strong interaction. Calculations have been carried out at both the Hartree–Fock and correlated (second‐order Møller–Plesset perturbation theory) levels of theory, using several different basis sets [6‐31G(d,p), 6‐311G(d,p), 6‐31G++(d,p), 6‐311G++(d,p), 6‐31++G(2d,2p) and 6‐311++G(2d,2p)]. The widely used a posteriori Boys–Bernardi counterpoise (CP) correction scheme has been compared with the a priori CHA/CE, CHA–MP2, and CHA–PT2 methods, using the chemical Hamiltonian approach (CHA). The results show that at both levels the CP and the appropriate CHA results are very close to each other. Only the monomer‐based CHA‐PT2 theory gives slightly overcorrected results, reflecting that the charge transfer and polarization effects are not taken into account in this method up to second order. We have also applied our earlier developed energy decomposition scheme in order to decompose the second‐order energy contribution into different physically meaningful components. The results show that at large and intermediate intermolecular distances, the second‐order intermolecular contribution is almost equal to the sum of different physically meaningful components (e.g., polarization, charge transfer, dispersion), while at shorter distances the slightly strong overlap effects fairly disturb this simple additivity. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Structures and isomerization of neutral and zwitterion serine–water clusters: Computational study
Authors: Jeon In‐Sun , Ahn Doo‐Sik , Park Sung‐Woo , Lee Sungyul , Kim Bongsoo
Published: September 2004

Calculations are presented for the structure and the isomerization reaction of various conformers of the bare serine, neutral serine–(H2O)n and serine zwitterion–(H2O)n (n = 1, 2) clusters. The effects of binding water molecules on the relative stability and the isomerization processes are examined. Hydrogen bonding between serine and the water molecule(s) may significantly affect the relative stability of conformers of the neutral serine–(H2O)n (n = 1, 2) clusters. The sidechain (OH group) in serine is found to have a profound effect on the structure and isomerization of serine–(H2O)n (n = 1, 2) clusters. Conformers with the hydrogen bonding between water and the hydroxyl group of serine are predicted. A detailed analysis is presented of the isomerization (proton transfer) pathways between the neutral serine–(H2O)2 and serine zwitterion–(H2O)2 clusters by carrying out the intrinsic reaction coordinate analysis. At least two water molecules need to bind to produce the stable serine zwitterion–water cluster in the gas phase. The isomerization for the serine–(H2O)2 cluster proceeds by the concerted double and triple proton transfer mechanism occurring via the binding water molecules, or via the hydroxyl group. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Erratum: Fillmore Freeman, Nina Asgari, Behrooz Entezam, Faranak Gomarooni, Jolene Mac, Monet H. Nguyen, Nhu N. T. Nguyen, Thao P. Nguyen, Ngoc B. Pham, Perveen Sultana, Timothy S. Welch, Bagrat A. Shainyan, “Computational study of sulfoxides of thiacyclohexane, 4‐silathiacyclohexane, 4‐fluoro‐4‐silathiacyclohexane, and 4,4‐difluoro‐4‐silathiacyclohexane: Relative energies of conformations and sulfinyl oxygen stabilized pentacoordinate silicon in boat and twist structures,” International Journal of Quantum Chemistry (2004)
Authors: Freeman Fillmore , Asgari Nina , Entezam Behrooz , Gomarooni Faranak , Mac Jolene , Nguyen Monet H. , Nguyen Nhu N. T. , Nguyen Thao P. , Pham Ngoc B. , Sultana Perveen , Welch Timothy S. , Shainyan Bagrat A.
Published: September 2004

The original article to which this Erratum refers was published in International Journal of Quantum Chemistry (2004)

The above affiliations were printed incorrectly. The correct affiliations are as follows.

1 Department of Chemistry, University of California, Irvine, California 92697‐2025

2 A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Division of Russian Academy of Science, 1 Favorsky Street, Irkutsk 664033, Russian Federation

We apologize for any inconvenience this may have caused.
Selective detection of monohydroxy metabolites of polycyclic aromatic hydrocarbons in urine using liquid chromatography/triple quadrupole tandem mass spectrometry
Authors: Xu Xu , Zhang Junfeng , Zhang Lin , Liu Weili , Weisel Clifford P.
Published: September 2004

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitously present in the environment and associated with a variety of adverse health effects. Monohydroxylated PAHs (OH‐PAHs), metabolites of PAHs, have been employed as biomarkers for human exposure assessment of PAHs. This manuscript describes new, selective detection methods for OH‐PAHs using liquid chromatography and tandem mass spectrometry (LC/MS/MS). Electrospray ionization was operated in the negative ion mode to detect the deprotonated PAH metabolites ([MH]−). Hydroxylated metabolites of naphthalene, fluorene, phenanthrene, fluoranthene, pyrene, benzo[c]phenanthrene, chrysene, benzo[a]anthracene, and benzo[a]pyrene were selected for the method development. Based on the collision‐induced dissociation MS/MS spectra of the selected OH‐PAHs, a characteristic ion fragmentation, loss of 28 Da from the [MH]− ion, was identified for all of these OH‐PAHs. This characteristic fragmentation was exploited for selective screening for OH‐PAHs in human urine by incorporating a constant neutral loss (CNL) scan with data‐dependent scanning, using a triple quadruple mass spectrometer. Selected reaction monitoring (SRM) was also used to tentatively identify isomers of the target OH‐PAHs in human urine. The excellent linearity (3–4 orders of magnitude) and signal‐to‐noise performance provided by the SRM method allowed development of a sensitive LC/MS/MS method for measuring OH‐PAHs in urine samples. The limits of detection of the SRM method ranged from approximately 0.1–5 pg on column for a suite of OH‐PAHs tested in the study. The LC‐SRM method was applied, following enzymatic deconjugation and solid‐phase extraction of the urine, to preliminarily determine the OH‐PAH concentrations in urine specimens from six Chinese non‐occupationally exposed workers and seven Chinese coke oven workers. Copyright © 2004 John Wiley & Sons, Ltd.
Identification of monovinyl tripropionic acid porphyrins and metabolites from faeces of patients with hereditary coproporphyria by high‐performance liquid chromatography/electrospray ionization quadrupole time‐of‐flight tandem mass spectrometry
Authors: Danton Malcolm , Lim Chang Kee
Published: September 2004

Harderoporphyrin (2‐vinyl‐4,6,7‐tripropionic acid porphyrin) and its metabolites in faeces of patients with hereditary coproporphyria (HCP) have been separated and characterized by high‐performance liquid chromatography/electrospray ionization quadrupole time‐of‐flight tandem mass spectrometry (HPLC/ESI‐Q‐TOFMS/MS). The metabolites identified were 2‐ethyl‐4,6,7‐tripropionic acid porphyrin, 2‐hydro‐4,6,7‐tripropionic acid porphyrin, 2‐methoxyethyl‐4,6,7‐tripropionic acid porphyrin and 2‐acetyl‐4,6,7‐tripropionic acid porphyrin. Isomers of harderoporphyrin derived from isomerization of harderoporphyrinogen were also detected. Copyright © 2004 John Wiley & Sons, Ltd.