bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractThe 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

AbstractThe 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

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

AbstractPurposeAlthough 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.MethodsData 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.ResultsAbout 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.ConclusionsOur 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

AbstractFrancisella 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

AbstractFour 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

AbstractSolvolysis 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

AbstractVery 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

AbstractTwo 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

AbstractA 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

AbstractSummary: 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.magnified imageEvolution 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

AbstractSummary: 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.‐%).magnified imageComparison 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

AbstractSmall‐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

AbstractGas 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

AbstractThe 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.