bluuebunny/crossref_metadata_2025 huggingface dataset:
Moments and distribution function of polyelectrolyte chains
Authors: Cannavacciuolo Luigi , Pedersen Jan Skov
Published: April 2004

It is demonstrated that the moments 〈R2k〉 of the end-to-end distance distribution function f(r) of charged wormlike chains with excluded volume effects in solution with added salt, in the Debye–Hückel approximation, obey a remarkably simple relation. It is shown that the 〈R2k〉 can be expressed as weighted sums of the corresponding moments of ideal wormlike chains. As an application of this method, we show that the Fourier transform of f(r) can also be represented by a superposition of distribution functions of ideal chains. The quantities so calculated are compared with the results of Monte Carlo simulations. Excellent agreement between them is observed.
Si
2
CN
:
A stable nitrogen-containing radical with cyclic ground state
Authors: Chen Guang-Hui , Ding Yi-Hong , Huang Xu-Ri , Yu Jian-Kang , Sun Chia-Chung
Published: April 2004

The structures and isomerization of Si2CN species are explored at density functional theory and ab initio levels. Fourteen minimum isomers are located connected by 23 interconversion transition states. At the coupled-cluster single double (CCSD)(T)/6-311+G(2df)//QCISD/6-311G(d) +zero-point vibrational energies level, the thermodynamically most stable isomer is a four-membered ring form cSiSiCN 1 with Si–C cross bonding. Isomer 1 has very strong C–N multiple bonding characters, formally suggestive of a radical adduct between Si2 and CN. Such a highly π-electron localization can effectively stabilize isomer 1 to be the ground state. The second low-lying isomer is a linear form SiCNSi 5 (9.8 kcal/mol above 1) with resonating structure among |Si=C⋅–N=Si|, ⋅|Si=C=N=Si|, and |Si=C=N–Si|⋅ with the former two bearing more weight. The species 1 and 5 have very high kinetic stability stabilized by the barriers of at least 25 kcal/mol. Both isomers should be experimentally or astrophysically observable. In light of the fact that no cyclic nitrogen-containing species have been detected in space, the cyclic species 1 could be a very promising candidate. The calculated results are compared to those of the analogous molecules C3N, C3P, SiC2N, and SiC2P. Implications of Si2CN in interstellar and N-doped SiC vaporization processes are also discussed.
Hydrogen bond-induced vibronic mode mixing in benzoic acid dimer: A laser-induced fluorescence study
Authors: Nandi Chayan K. , Chakraborty Tapas
Published: April 2004

Laser-induced dispersed fluorescence spectra of benzoic acid dimer in the cold environment of supersonic jet expansion have been reinvestigated with improved spectral resolution of measurements. The spectra are analyzed with the aid of the normal mode vibrations of the dimer calculated by the ab initio quantum chemistry method at the DFT/B3LYP/6-311+G** level of theory. The analysis reveals that the low-frequency intermolecular hydrogen bond modes are mixed extensively with the carboxyl as well as aromatic ring vibrations upon electronic excitation. The mode mixing is manifested as the complete loss of mirror symmetry relation between the fluorescence excitation and dispersed fluorescence spectra of the S1 origin, and appearance of large number of cross-sequence transitions when the DF spectra are measured by exciting the low-energy vibrations near the S1 origin. The cross-sequence bands are found in all the cases to be the combinations of two nontotally symmetric fundamentals consisting of one of the intermolecular hydrogen bond modes and the other from the aromatic ring and carboxyl group vibrations. The implications of this mode mixing on the excited state dynamics of the dimer are discussed.
Effects of resolution and friction in the interpretation of QHAS measurements
Authors: Jardine A. P. , Ellis J. , Allison W.
Published: April 2004

We use Langevin molecular dynamics (MD) simulations to improve the picture of the processes that contribute to QHAS broadening, as a function of momentum transfer at the crystal. We use a simulation of realistic damped vibrational motion in a harmonic well to establish the contributions to QHAS measurements due to both vibrational motion and intracell diffusion (usually referred to as vibrational dephasing). We demonstrate the experimental conditions under which such contributions are likely to be important. These results are compared with those from a simulation of thermal diffusion over a sinusoidally corrugated potential. We show that resolution and atom-surface “friction” play an important role in determining the form of QHAS measurements and we demonstrate that there is no simple relationship between the “activation energy” derived from an Arrhenius plot of QHAS data and the adiabatic potential barrier height. MD simulations are therefore necessary to perform a complete analysis of the data. Finally, we discuss the application of our results to more sophisticated potentials, particularly those with multiple adsorption sites.
Full configuration interaction calculation of Be3
Authors: Junquera-Hernández José Miguel , Sánchez-Marı́n José , Bendazzoli Gian Luigi , Evangelisti Stefano
Published: April 2004

The full configuration interaction (FCI) study of the ground state of the neutral beryllium trimer has been performed using an atomic natural orbitals [3s2p1d] basis set. Both triangular and linear structures have been considered for the Be3 cluster. The optimal geometry for the equilateral triangle has been calculated. The potential energy cut sections along the normal a1′ mode and one of the components of the e′ mode have then been studied. The FCI symmetric atomization potential of the linear cluster is also reported. It shows a secondary van der Waals minimum at a long bond distance. All singular points in the potential energy curves are characterized. Other properties, like dissociation energies De and vibrational frequencies, have been estimated from a fourth-order fitting of a large range of points around the minima. The calculated FCI wave number values for the ν1 and ν2 normal modes are (467.33±0.43) cm−1 and (390.77±0.56) cm−1.
Ab initio many-body investigation of structure and stability of two-fold rings in silicates
Authors: Mukhopadhyay A. B. , Dolg M. , Oligschleger C.
Published: April 2004

In this paper we present ab initio many-body calculations on the strain energy of W silica, taken as a model system for edge-sharing tetrahedral SiO2 systems with respect to corner-sharing ones as in α quartz. The mean-field results were obtained using the restricted Hartree–Fock approach, while the many-body effects were taken into account by the second-order Møller–Plesset perturbation theory and the coupled-cluster approach. Correlation contributions are found to play an important role to determine the stability of edge-sharing units. The most sophisticated method used in our calculation, i.e., the coupled-cluster approach with single and double excitations, yields a strain energy of 0.0427 a.u. per Si2O4 unit with respect to α quartz, which is even smaller than the value obtained by a previous density functional theory calculation.
Comment on “Equations of state for fluids: The Dieterici approach revisited” [J. Chem. Phys. 115, 1460 (2001)]
Authors: Cachadiña I. , Mulero A. , Silbert M.
Published: April 2004

The assertion by Sadus [J. Chem. Phys. 115, 1460 (2001); 116, 5913(E) (2002)] that the Dieterici–Carnahan–Starling (DCS) equation of state he has proposed yields more accurate predictions of the phase coexistence of fluids than the traditional additive approach used to develop equations of state is challenged. The main point invoked concerns the behavior of mean-field equations of state in the neighborhood of the critical point. It is concluded that, whereas the DCS equation of state may be a useful addition, it is not more accurate over the whole of the phase coexistence of fluids than existing, additive, equations of state.
Intermolecular potential energy surface and rovibrational spectra of the He–N2O complex from ab initio calculations
Authors: Zhou Yanzi , Xie Daiqian
Published: April 2004

We report an ab initio intermolecular potential energy surface calculation on the He–N2O complex with N2O at its ground state using a supermolecular approach. The calculation was performed at the coupled-cluster [CCSD(T)] level, with the full counterpoise correction for the basis set superposition error and a large basis set including midpoint bond functions. The CCSD(T) potential is found to have two minima corresponding to the T-shaped and linear He–ONN structures. The T-shaped minimum is the global minimum. The two-dimensional discrete variable representation method was employed to calculate the rovibrational energy levels for He–N24O and He–N23O with N2O at its ground and ν3 excited states. The results indicate that the CCSD(T) potential supports five and four vibrational bound states for the He–N24O and He–N23O, respectively. Moreover, the calculations on the line intensities of the rotational transitions in the ν3 region of N2O for the ground vibrational state shows that the He–N23O spectrum is dominated by a-type transitions (ΔKa=0), while the He–N24O spectrum is contributed by both the a-type and b-type (ΔKa=±1) transitions. The calculated transition frequencies and the intensities are in good agreement with the observed results.
Impaired Clearance of Apoptotic Cells Promotes Synergy between Atherogenesis and Autoimmune Disease
Authors: Aprahamian Tamar , Rifkin Ian , Bonegio Ramon , Hugel Bénédicte , Freyssinet Jean-Marie , Sato Kaori , Castellot John J. , Walsh Kenneth
Published: April 2004

To clarify the link between autoimmune disease and hypercholesterolemia, we created the gld.apoE−/− mouse as a model of accelerated atherosclerosis. Atherosclerotic lesion area was significantly increased in gld.apoE−/− mice compared with apoE−/− mice. gld.apoE−/− mice also displayed increases in lymphadenopathy, splenomegaly, and autoantibodies compared with gld mice, and these effects were exacerbated by high cholesterol diet. gld.apoE−/− mice exhibited higher levels of apoptotic cells, yet a reduced frequency of engulfed apoptotic nuclei within macrophages. Infusion of lysophosphatidylcholine, a component of oxidized low density lipoprotein, markedly decreased apoptotic cell clearance in gld mice, indicating that hypercholesterolemia promotes autoimmune disease in this background. These data suggest that defects in apoptotic cell clearance promote synergy between atherosclerotic and autoimmune diseases.
Comparisons of Korsakoff and Non‐Korsakoff Alcoholics on Neuropsychological Tests of Prefrontal Brain Functioning
Authors: Oscar‐Berman Marlene , Kirkley Shalene M. , Gansler David A. , Couture Ashley
Published: April 2004

Abstract: Background: Evidence suggests that alcoholics exhibit particular deficits in brain systems involving the prefrontal cortex, but few studies have directly compared patients with and without Korsakoff's syndrome on measures of prefrontal integrity.

Methods: Neuropsychological tasks sensitive to dysfunction of frontal brain systems were administered, along with standard tests of memory, intelligence, and visuospatial abilities, to 50 healthy, abstinent, nonamnesic alcoholics, 6 patients with alcohol‐induced persisting amnestic disorder (Korsakoff's syndrome), 6 brain‐damaged controls with right hemisphere lesions, and 82 healthy nonalcoholic controls.

Results: Korsakoff patients were impaired on tests of memory, fluency, cognitive flexibility, and perseveration. Non‐Korsakoff alcoholics showed some frontal system deficits as well, but these were mild. Cognitive deficits in non‐Korsakoff alcoholics were related to age, duration of abstinence (less than 5 years), duration of abuse (more than 20 years), and amount of alcohol intake.

Conclusions: Abnormalities of frontal system functioning are most apparent in alcoholics with Korsakoff's syndrome. In non‐Korsakoff alcoholics, factors contributing to cognitive performance are age, duration of abstinence, duration of alcoholism, and amount of alcohol consumed.
Comparison of the Onset of Hypoactivity and Anxiety‐Like Behavior During Alcohol Withdrawal in Adolescent and Adult Rats
Authors: Slawecki Craig J. , Roth Jennifer
Published: April 2004

Abstract: Background: Early life alcohol use is associated with increased alcoholism risk. It has been suggested that alterations in the sensitivity of adolescents to the acute effects of ethanol may contribute to this risk by promoting excessive intake. However, an enhanced propensity for developing ethanol dependence or withdrawal‐related behavior could also contribute to increased risk. The objective of these studies was to compare the appearance of ethanol withdrawal‐related behaviors in adolescent and adult rats.

Methods: Male Sprague‐Dawley rats were exposed to ethanol vapor (12 hr/day) for 12 or 14 days during adolescence or adulthood. In the first study, locomotor activity was assessed after 2, 4, 7, 10, and 14 days of ethanol exposure. In the second study, open field behavior was assessed after 5 or 12 days of ethanol exposure. In follow‐up studies, changes in sucrose preference during ethanol withdrawal and motor activity during food restriction were assessed in adolescent rats. Withdrawal assessments were made 7 to 9 hr after daily exposure ended.

Results: Hypoactivity emerged rapidly in adolescent rats during ethanol withdrawal in activity tests, but comparable reductions were not found in adult rats. However, hypoactivity developed in both adolescents and adults in the novel open field. Enhanced anxiety‐like behavior in the open field was not observed in either age group during withdrawal. Finally, sucrose preference was unchanged during ethanol withdrawal, and food restriction increased motor activity in adolescent rats.

Conclusions: These data confirm that symptoms of withdrawal may be differentially expressed in adolescent and adult rats. However, discrepancies in hypoactivity between studies suggest that assessment in a novel versus familiar environment may influence the expression of withdrawal‐related behaviors.
Genetic and phenotypic analysis of biofilm phenotypic variation in multiple Staphylococcus epidermidis isolates
Authors: Handke L. D. , Conlon K. M. , Slater S. R. , Elbaruni S. , Fitzpatrick F. , Humphreys H. , Giles W. P. , Rupp M. E. , Fey P. D. , O'Gara J. P.
Published: April 2004

Production of biofilm in Staphylococcus epidermidis is mediated through enzymes produced by the four-gene operon ica and is subject to phenotypic variation. The purpose of these experiments was to investigate the regulation of ica and icaR transcription in phenotypic variants produced by multiple unrelated isolates of S. epidermidis. Ten isolates were chosen for the study, four of which contained IS256. IS256 mediates a reversible inactivation of ica in approximately 30 % of phenotypic variants. All ten strains produced at least two types of phenotypic variant (intermediate and smooth) in which biofilm formation was significantly impaired. Reversion studies indicated that all phenotypic variants were stable after overnight growth, but began to revert to other phenotypic forms after 5 days of incubation at 37 °C. ica transcriptional analysis was performed on phenotypic variants from three IS256-negative isolates; 1457, SE5 and 14765. This analysis demonstrated that ica transcription was significantly reduced in the majority of phenotypic variants, although two variants from SE5 and 1457 produced wild-type quantities of ica transcript. Analysis of seven additional phenotypic variants from SE5 revealed that ica expression was only reduced in three. Expression of icaR transcript was unaffected in all smooth phenotypic variants. Mutations within ica were identified in two SE5 variants with wild-type levels of ica transcription. It is concluded that mutation and transcriptional regulation of ica are the primary mechanisms that govern phenotypic variation of biofilm formation within IS256-negative S. epidermidis.
Comparison of the binding properties of the mushroom Marasmius oreades lectin and Griffonia simplicifolia I‐B4 isolectin to αgalactosyl carbohydrate antigens in the surface phase
Authors: Kirkeby Svend , Winter Harry C. , Goldstein Irwin J.
Published: April 2004

Abstract:  The binding of two α‐galactophilic lectins, Marasmius oreades agglutinin (MOA), and Griffonia simplicifolia I isolectin B4 (GS I‐B4) to neoglycoproteins and natural glycoproteins were compared in a surface phase assay. Neoglycoproteins carrying various α‐galactosylated glycans and laminin from basement membrane of mouse sarcoma that contains the xenogenic Galα1–3Gal1–4GlcNAc epitope were immobilized in microtiter plate wells and lectin binding determined with an enzyme‐linked assay. After 24 h of incubation, MOA had higher affinity for the xenogenic pentasaccharide (Galα1–3Gal1–4GlcNAcβ1–3Galβ1–4Glc) than for the Galα‐monosaccharide. The binding properties of MOA and GS I‐B4 to the xenogenic disaccharide (Galα1–3Galβ1) were comparable while the binding of MOA to the xenogenic pentasaccharide was much stronger than the binding of GS I‐B4 to the same epitope. Non‐xenogenic disaccharide‐coupled neoglycoproteins having galactose end groups linked α1–2 or α1–4 to Gal or linked α1–3 to GalNAc bound very weakly to MOA, whereas GS I‐B4 recognized all of these disaccharides with similarly high affinity. MOA also showed high affinity for laminin. The results indicate that the Marasmius oreades lectin has nearly the same affinities as does GS I‐B4 for the simple xenogenic carbohydrate antigens, but MOA has greater affinity for the pentasaccharide and is far more specific in its binding preferences than the Griffonia lectin.
The graft content of hyaluronan is increased during xenograft rejection
Authors: Lorant Tomas , Tufveson Gunnar , Johnsson Cecilia
Published: April 2004

Abstract:  Background:  Hyaluronan, a macromolecule with strong water binding capacity, is associated with interstitial oedema during rejection of allogeneic transplants. However, the involvement of hyaluronan during xenograft rejection has previously not been investigated. The aims of this study were to characterize hyaluronan content and distribution during rejection of concordant mouse‐to‐rat cardiac xenografts, and to explore the effects of hyaluronidase (HAse) on xenograft survival.

Methods:  Graft recipients were treated with 15‐deoxyspergualin (DSG) or both HAse and DSG. Grafts were removed on day 5 from some of the animals to analyse hyaluronan and water content, while other animals were used to investigate graft survival. The hyaluronan content was measured by a radiometric assay and the distribution was analysed by histochemical staining.

Results:  In xenografts undergoing rejection (the DSG group) there was a strong increase of the hyaluronan [555 ± 93 μg/g dry weight (dw)] and water (82.7 ± 0.4%) contents compared with normal mouse heart tissue (166 ± 10 μg/g dw; P < 0.01 and 78.6 ± 0.5%; P < 0.001, respectively). The combined use of HAse and DSG reduced the accumulation of hyaluronan (284 ± 43 μg/g dw; P < 0.05 vs. DSG) but did not affect the average water content. The average graft survival time did not differ between the groups; however, three grafts in the HAse + DSG‐treatment group survived much longer than the longest‐surviving grafts in the DSG group.

Conclusions:  These data suggest that the graft content of hyaluronan considerably increases during xenograft rejection. HAse effectively reduces this accumulation, but does not affect the average water content.
Combinatorial approaches to protein stability and structure
Authors: Magliery Thomas J. , Regan Lynne
Published: April 2004

Why do proteins adopt the conformations that they do, and what determines their stabilities? While we have come to some understanding of the forces that underlie protein architecture, a precise, predictive, physicochemical explanation is still elusive. Two obstacles to addressing these questions are the unfathomable vastness of protein sequence space, and the difficulty in making direct physical measurements on large numbers of protein variants. Here, we review combinatorial methods that have been applied to problems in protein biophysics over the last 15 years. The effects of hydrophobic core composition, the most important determinant of structure and stability, are still poorly understood. Particular attention is given to core composition as addressed by library methods. Increasingly useful screens and selections, in combination with modern high‐throughput approaches borrowed from genomics and proteomics efforts, are making the empirical, statistical correlation between sequence and structure a tractable problem for the coming years.
Identification of NF1 as a silencer protein of the human adenine nucleotide translocase‐2 gene
Authors: Barath Peter , Poliakova Daniela , Luciakova Katarina , Nelson B. Dean
Published: April 2004

The human adenine nucleotide translocase‐2 (ANT2) promoter contains a silencer region that confers partial repression on the heterologous herpes simplex virus thymidine kinase (HSVtk) promoter [Barath, P., Albert‐Fournier, B., Luciakova, K., Nelson, B.D. (1999) J. Biol. Chem.274, 3378–3384]. Two sequences in the silencer (Site‐2 and Site‐3) are protected in the DNase I assay in vitro, and one of these is a repeated GTCCTG element previously shown to act as the active repressor element. We have now purified the DNA binding protein, and identified it using MALDI‐TOF MS as a 33‐kDa member of the nuclear factor 1 (NF1) family of transcription factors. NF1 purified from rat liver and HeLa cell nuclei bind to both silencer Site‐2 and Site‐3, resulting in a DNase I footprint identical to that obtained with purified recombinant NF1. Furthermore, transient transfection experiments with reporter constructs containing mutated silencer Site‐2 and/or Site‐3 show that both sites contribute to repression of the HSVtk promoter. Finally, chromatin immunoprecipitation analysis reveals that NF1 is bound to both elements on the endogenous HeLa cell ANT2 promoter. Our data support the belief that NF1 acts as a repressor when bound to silencing Site‐2 and Site‐3 of the ANT2 gene.
Characterization of the cofactor‐independent phosphoglycerate mutase from Leishmania mexicana mexicana
Authors: Guerra Daniel G. , Vertommen Didier , Fothergill‐Gilmore Linda A. , Opperdoes Fred R. , Michels Paul A. M.
Published: April 2004

Phosphoglycerate mutase (PGAM) activity in promastigotes of the protozoan parasite Leishmania mexicana is found only in the cytosol. It corresponds to a cofactor‐independent PGAM as it is not stimulated by 2,3‐bisphosphoglycerate and is susceptible to EDTA and resistant to vanadate. We have cloned and sequenced the gene and developed a convenient bacterial expression system and a high‐yield purification protocol. Kinetic properties of the bacterially produced protein have been determined (3‐phosphoglycerate: Km = 0.27 ± 0.02 mm, kcat = 434 ± 54 s−1; 2‐phosphoglycerate: Km = 0.11 ± 0.03 mm, kcat = 199 ± 24 s−1). The activity is inhibited by phosphate but is resistant to Cl– and SO42–. Inactivation by EDTA is almost fully reversed by incubation with CoCl2 but not with MnCl2, FeSO4, CuSO4, NiCl2 or ZnCl2. Alkylation by diethyl pyrocarbonate resulted in irreversible inhibition, but saturating concentrations of substrate provided full protection. Kinetics of the inhibitory reaction showed the modification of a new group of essential residues only after removal of metal ions by EDTA. The modified residues were identified by MS analysis of peptides generated by trypsin digestion. Two substrate‐protected histidines in the proximity of the active site were identified (His136, His467) and, unexpectedly, also a distant one (His160), suggesting a conformational change in its environment. Partial protection of His467 was observed by the addition of 25 µm CoCl2 to the EDTA treated enzyme but not of 125 µm MnCl2, suggesting that the latter metal ion cannot be accommodated in the active site of Leishmania PGAM.
2003 Lawrence R. Klein Lecture  The Case Against Intellectual Monopoly*
Authors: Boldrin Michele , Levine David K.
Published: April 2004

In the modern theory of growth, monopoly plays a crucial role both as a cause and an effect of innovation. Innovative firms, it is argued, would have insufficient incentive to innovate should the prospect of monopoly power not be present. This theme of monopoly runs throughout the theory of growth, international trade, and industrial organization. We argue that monopoly is neither needed for, nor a necessary consequence of innovation. In particular, intellectual property is not necessary for, and may hurt more than help, innovation and growth. We argue that, as a practical matter, it is more likely to hurt.
Specific Factors, Learning, and the Dynamics of Trade*
Authors: Bajona Claustre
Published: April 2004

In the postwar period, the volume of trade among developed countries has increased at a much higher rate than GDP. This article presents a dynamic general equilibrium model of trade between developed countries that accounts for this pattern of trade dynamics. Countries trade in goods that use good‐specific skilled labor and unskilled labor as factors of production. Specific skills are learned on the job and there exist positive effects in learning. Small initial differences in the distribution of experts in each country generate an increasing pattern of specialization over time. Knowledge spillovers across sectors are crucial determinants of the trade pattern.
Three‐dimensional ultrasonographic assessment of fetal lung volume as prognostic factor in isolated congenital diaphragmatic hernia
Authors: Ruano Rodrigo , Benachi Alexandra , Joubin Laurence , Aubry Marie‐Cécile , Thalabard Jean‐Christophe , Dumez Yves , Dommergues Marc
Published: April 2004

Objective  To evaluate the potential of three‐dimensional ultrasound to predict outcome in congenital diaphragmatic hernia.

Design  Prospective observational study.

Setting  Tertiary care centre.

Population  Twelve cases of isolated congenital diaphragmatic hernia (11 left‐sided, 1 right‐sided) and 109 controls.

Methods  Fetal lung volume was assessed by three‐dimensional ultrasound using the technique of rotation of the multiplanar imaging. In the control fetuses, a logistic transformation was performed to correlate fetal lung volume with gestational age, and the confidence interval was obtained with a bootstrap resampling. A mathematical equation was then obtained allowing calculation of the expected fetal lung volume as a function of gestational age. In fetuses with congenital diaphragmatic hernia, the observed/expected lung volume ratio was compared with postnatal outcome.

Main outcome measures  Neonatal mortality and pulmonary hypoplasia, which was defined as lung/body weight ratios less than 0.012.

Results  The expected fetal lung volume was derived from the mathematical equation: Fetal lung volume (mL) = exp (4.72/(1 + exp ((20.32 − gestational age in weeks)/6.05))). The observed/expected fetal lung volume ratio was significantly lower in the congenital diaphragmatic hernia group (median: 0.34, range: 0.16–0.66), than in the control group (median: 1.02, range: 0.62–1.97, P < 0.0001). The distribution of this ratio was significantly downshifted in the infants with congenital diaphragmatic hernia who died (median: 0.19, range: 0.18–0.66) compared with survivors (median: 0.44, range: 0.36–0.66, P= 0.04). The observed/expected fetal lung volume ratio was also correlated with the postmortem lung/body weight ratio.

Conclusion  In isolated congenital diaphragmatic hernia, fetal lung volume measurement by three‐dimensional ultrasound is a potential predictor for pulmonary hypoplasia and postnatal outcome.
A randomised comparison of oral misoprostol and vaginal prostaglandin E2 tablets in labour induction at term
Authors: Shetty A. , Livingstone I. , Acharya S. , Rice P. , Danielian P. , Templeton A.
Published: April 2004

Objective  To compare the efficacy of 100 μg of oral misoprostol with 3 mg prostaglandin E2 vaginal tablets in term labour induction.

Design  A non‐blinded, randomised, controlled trial.

Setting  A tertiary level, teaching Scottish Hospital.

Population  Two hundred women at term with indications for labour induction and modified Bishop's cervical score of less than 8.

Methods  The women were randomly allocated to receive either 100 μg of misoprostol orally (which could be repeated 4 hourly to a maximum of five doses if indicated), or a 3 mg tablet of prostaglandin E2 vaginally (which could be repeated in 6 hours, according to routine departmental protocol).

Main outcome measure  The number delivering vaginally within 24 hours of the induction.

Results  Seventy‐five women delivered vaginally in the misoprostol group and 73 in the PGE2 group. Of these, 50.7% in the misoprostol group and 54.8% in the PGE2 group delivered within 24 hours of the induction (RR 0.92, 95% CI 0.7 to 1.3). More women in the misoprostol group were given oxytocin, but this was not statistically significant (60%vs 47%, RR 1.3, 95% CI 0.98 to 1.7). Two women in the misoprostol group had uterine hyperstimulation. The neonatal outcomes were not significantly different in the two groups. There was a £1100 saving on direct drug costs in the misoprostol group.

Conclusions  Oral misoprostol (100 μg) has similar efficacy to vaginal PGE2 tablets, and may be an option to consider for term labour induction.
Pelvic floor dysfunction in women after pelvic trauma
Authors: Baessler K. , Bircher M.D. , Stanton S.L.
Published: April 2004

The aim was to assess symptoms of pelvic floor dysfunction in women following pelvic trauma. A retrospective questionnaire survey of 24 consecutive women was performed in a tertiary referral orthopaedic centre and urogynaecology unit. Sixteen women had a type B and eight a type C pelvic fracture (Association Osteosynthesis manual classification). The median age was 24 years (11–92). Twenty‐one women were nulliparous. Sixteen women reported de novo pelvic floor dysfunction. Bladder symptoms occurred in 12, bowel problems in 11 and sexual dysfunction in 7 of 17 sexually active women. Pelvic fracture seems to be a risk factor for pelvic floor dysfunction.
Expectant or surgical management of miscarriage: a qualitative study
Authors: Ogden Jane , Maker Cathy
Published: April 2004

Objective  To explore women's reasons for selecting either expectant or surgical management of first trimester miscarriage and to examine the impact of treatment upon them.

Design  A qualitative study using interviews.

Setting  The Early Pregnancy and Gynaecology Assessment Unit at a London hospital.

Sample  Thirteen women diagnosed as having a first trimester miscarriage who had opted for either expectant management (n= 5), surgical management (n= 5) or who had undergone both (n= 3).

Methods  Qualitative in depth interviews.

Main outcome measures  The experience of management.

Results  The choice of expectant management was motivated by desire for a natural solution and a fear of operation. Women described how pain and bleeding had made them anxious, that something was wrong and how they felt unprepared for how gruelling the experience would be. Some also described how their support had dwindled as the miscarriage progressed. In contrast, women who chose surgery valued a quick resolution and focussed on the support from hospital staff, although some commented that their emotional needs had not always been met.

Conclusion  If expectant management is to be more widely offered, women should be told not only of the likely clinical effect of letting a miscarriage run its course but also how women experience this.
Maternal Role Attainment in Adolescent Mothers: Foundations and Implications
Authors: Sartore Ann T.
Published: April 2004

(1) Maternal role attainment (MRA) is a process in which a mother achieves competence in her role and integrates the mothering behaviors into her established role set, so she is comfortable with her identity as mother. Age is consistently identified as a variable in MRA. This paper reviews literature on MRA in an exploration of its theoretical foundation and implications for adolescents. Practice implications include assessment of maternal affect and behavior, education, and follow‐up for adolescent mothers. Inclusion of the adolescent's social support in interventions is advocated. Limited studies available support the need for future research in MRA in adolescents.
Family Businesses and Employee Ownership
Authors: Weiser John , Brody Frances , Quarrey Michael
Published: April 2004

Employee ownership, properly structured, enhances the strengths of family-owned firms and offers significant financial benefits. Employee ownership is often of particular interest to family firms when an owner is seeking to retire and has no heirs interested in continuing in the business.
A Historical Overview of Family Firms in the United States
Authors: Hall Peter Dobkin
Published: April 2004

How do dynastic families adopt to social and economic forces restricting attempts to transmit family wealth from one generation to the next?
An Organizational Development/Team-Building Approach to Consultation with Family Businesses
Authors: Lane Sam H.
Published: April 2004

The approach to consultation with family businesses described in this article emphasizes having the family work as a team on issues and problems affecting the business and the family. Combining the insights of applied psychology with principles of sound business management, it aims at helping the family learn to make good business decisions while maintaining positive relationships among family members.
Family Firms as Utopian Organizations
Authors: Guzzo Richard A. , Abbott Susan
Published: April 2004

Utopian communities and family firms share a fusion of family and work life. This article examines their similarities with regard to organizational ideals, mechanisms of commitment, and the exercise of authority.
Sibling Relationships and Intergenerational Succession in Family Firms
Authors: Friedman Stewart D.
Published: April 2004

Sibling relationships can turn into rivalries that destroy family firms. In this article, clinical and theoretical research on families, organizations, and conflict resolution are drawn on to develop intervention strategies aimed at helping family firm members both increase awareness about forces that sustain destructive sibling conflicts and find ways of working through them. Competition for parental love and attention spurs sibling rivalry. Whether siblings become rivalrous depends largely on parental responses to this contest. Because adult brothers and sisters in family firms remain organizationally subordinated to their parents, they face unique challenges in overcoming sibling rivalry's harmful effects. Yet this is precisely the task confronting them if they are to sustain family management of their business through intergenerational succession.
Understanding and Working with Leading Family Businesses in Latin America
Authors: Lansberg Ivan , Perrow Edith
Published: April 2004

Most Latin American economies are dominated by large cosmopolitan family businesses referred to as grupos. This article examines how the unique economic, political, and sociocultural characteristics of Latin America affect the ownership, management, and family dynamics of these organizations.
Proprietorial Control in Family Firms: Some Functions of “Quasi-Organic” Management System
Authors: Goffee Robert , Scase Richard
Published: April 2004

The purpose of this paper is to investigate the strategies of managerial control which are used by the proprietors of family-owned business enterprises. Interviews with the proprietors and senior managers of businesses in the building industry illustrate the “quasi-organic” nature of management structures. These grant some autonomy to senior managers without threatening proprietorial decision-making prerogatives. Although the family firm has certain distinctive features, similar control strategies designed to ensure that delegated decisions are “reliable” and “responsible” are evident in various types of business enterprise. There is, then, scope for further comparative research within a conceptual framework which does not entirely divorce the family firm from other business organizations.
Connecting and Separating Family and Business: A Relational Approach to Consultation
Authors: Flemons Douglas G. , Cole Patricia M.
Published: April 2004

A number of theoretical orientations to family business consultation have been proposed and developed. This article acknowledges these contributions but sets out to take afresh look at the process, using the interconnected notions of relationship and context to organize the discussion. Case examples are provided as illustration.
Reflections on the Family Business Literature: Pioneers Look to the Past and the Future
Authors: Gersick Kelin E.
Published: April 2004

In keeping with the review format of this handbook, this interview feature asks three of the founders of the field to reflect on their entry into this area of work and their impressions of its development.
A Neglected Factor Explaining Family Business Success: Human Resource Practices
Authors: Astrachan Joseph H. , Kolenko Thomas A.
Published: April 2004

Over 600 family firms were involved in this examination of the impact of human resource management (HRM) and professional governance practices on family business success and survival. Our findings identified some of the most prevalent family firm HRM practices and found significant positive correlations among HRM practices, gross firm revenues, and CEO personal income levels. The results support prior arguments for competitive advantage in the marketplace gained through effective use of HRM practices. An interesting additional finding was that while boards of directors, strategic planning, and frequent family meetings were correlated with business longevity over multiple generations, succession planning was not. Such practices are important. for current competitive advantage and may also be crucial to the longevity of the business.
Loyola University Chicago Family Firm Stock Index
Authors: McConaughy Daniel L. , Mendoza Drew , Mishra Chandra
Published: April 2004

The Loyola University Chicago Family Firm Stock Index (LUCFFSI) tracks the performance of publicly traded, family controlled firms headquartered in the Chicago area. Family controlled firms have governance structures that are expected to result in improved performance compared to non-family controlled firms. The LUCFFSI, over the period from September 28, 1990, to July 28, 1995, outperformed local and national indices. We discuss the design of this price-weighted index. Statistical testing (detailed in a technical appendix) and existing price-weighted indices such as Crain's Chicago Stock Index and the Dow Jones Industrial Average, suggest that the price-weighted design is preferable to a market value (cap)-weighted design. We suggest that a continually updated price-weighted Loyola University Chicago Family Firm Stock Index can serve as a significant performance benchmark.
A Comparison of Four Countries' Estate Laws and Their Influence on Family Companies
Authors: Davis John A. , Swartz Jeffrey , Blakely Elizabeth B. , Chang Christopher , Eyzaguirre G. José María , Mattson Robert , Pettker John D.
Published: April 2004

Estate laws can have a significant effect on ownership transfers for family companies, influencing both the ease of the transfer and who receives shares of the company. By comparing the estate laws of various countries, we not only can learn about the culture of a country, but also gain insights into the effects of these laws on family business. A review of four countries' estate laws (for the United States, Finland, Chile, and Taiwan) demonstrates four philosophies and approaches to intergenerational wealth distribution. The authors discuss some implications of these laws on ownership transfers in family companies.
Effects of Family Business Membership and Psychological Separation on the Career Development of Late Adolescents
Authors: Eckrich Christopher J. , Loughead Teri A.
Published: April 2004

Family businesses are reported to consist of overinvolved family relationships. Overinvolvement often leads to conflict when late adolescents attempt to develop their own identity, separate from the home, and choose an occupation. This study examines differences between family-and non-family-business offspring in relation to psychological overinvolvement, and career choice and development. Analyses of assessments completed by 248 undergraduate college students does not support the belief that family business members are overinvolved with each other, but does suggest implications for the career development of family business offspring.
Combining and Contacting of Two Rough Surfaces with Asymmetric Distribution of Asperity Heights
Authors: Yu Ning , Polycarpou Andreas A.
Published: April 2004

The statistical approach of describing rough surfaces is extended to include the contact of two rough surfaces in which their distribution of asperity heights can either be symmetric or asymmetric, and the asymmetry is modeled using the normalized Weibull distribution. In considering the contact between two rough surfaces, as in most practical applications, the contact can be approximated by an equivalent rough surface in contact with a smooth plane. The roughness parameters of the equivalent surface are obtained using the spectral moment method, and its validity is verified using realistic surface roughness measurements. This paper presents a method to obtain the equivalent rough surface with a Weibull distribution of asperity heights, in which the standard deviation and skewness parameters of asperity heights of the actual contacting surfaces are preserved. The advantages of this method are demonstrated via direct comparisons with a previously proposed method as well as with exact numerical simulation of the contact parameters of several different actual surfaces from magnetic storage and MEMS applications. For practical engineering applications, where the roughness parameters of each individual surface are known, contour plots for the skewness value of the equivalent rough surface are provided for practical ranges of combinations of standard deviation ratios and skewness values. As expected when the roughness of one of the contacting surfaces dominates, the skewness is solely determined by the rougher surface.
Transient Thermoelastic Contact of Sliding Rings With Axisymmetric Surface Roughness
Authors: Wang C.-H. , Soom A. , Dargush G. F.
Published: April 2004

Many devices such as seals, clutches, and brakes involve the thermomechanical contact of rough surfaces in sliding motion. The asperity level interactions which are highly localized depend upon the thermal distortion of the interface and possibly the instantaneous overall shape of the sliding components. In this paper we present a boundary element method for the analysis of such problems; simultaneously, from the micro-asperity to the component level. The interdependence of micro-asperity and component level deformations is demonstrated via the transient thermoelastic analysis of sliding rings with axisymmetric roughness.
Dominance of missing fundamental versus spectrally cued pitch: Individual differences for complex tones with unresolved harmonics
Authors: Renken Remco , Wiersinga-Post J. Esther C. , Tomaskovic Sonja , Duifhuis Hendrikus
Published: April 2004

In a two-alternative, forced-choice experiment, subjects had to compare the pitches of two sounds, A and B. Each sound was composed of four successive harmonics of a fundamental frequency between 100 to 250 Hz, added in cosine or Schröder phase. The harmonic frequencies of A were lower than those of B; the missing fundamental frequency of A was higher than that of B. The dominance of the missing fundamental versus the spectrally cued pitch—a pitch percept corresponding to spectral components—was measured as a function of nA, the lowest harmonic in A. The pitch percept is dominated by the missing fundamental if the harmonics are resolved (nA<7). If the harmonics become unresolved and are added in Schröder phase, the dominance shifts to a spectrally cued pitch (7<nA<13; 75% of the subjects). In the cosine phase condition, many subjects could detect the fundamental pitch well into the unresolved harmonic range (nA>20). For others, the transition was in the realm of partly resolved harmonics. This shows that the temporal envelope modulation of stimuli with only four unresolved harmonics can give a relatively clear fundamental pitch percept. However, this percept varies considerably among subjects.
Laser-generated thermoelastic acoustic sources in anisotropic materials
Authors: Hurley David H.
Published: April 2004

An analytical model appropriate for thermoelastic generation of acoustic waves in anisotropic materials is presented for both plane and line sources. The interaction of acoustic waves produced by subsurface sources with the bounding surface is accounted for using a method of images. For the plane source case, analytical solutions are found that form an appropriate basis for an angular spectrum of plane waves. For the line source case and for specific crystal symmetries and source orientations, it is shown in the limit of strong optical absorption, a buried line source is equivalent to applying a shear stress dipole at the bounding surface. However, contrary to the isotropic case, the character and strength of the equivalent surface stress is a function of propagation direction.
Spectral integration of synchronous and asynchronous cues to consonant identification
Authors: Buss Emily , Hall Joseph W. , Grose John H.
Published: April 2004

The goal of the present research was to determine how well observers utilize cues to consonant identification from different spectral regions that occur asynchronously as opposed to synchronously across frequency; such an ability would be useful for processing speech in the context of a spectro-temporally complex masker (e.g., competing speech). This was assessed by obtaining masked identification thresholds for VCV speech material, of the form /a/ C /a/, under various conditions of 10-Hz or 20-Hz square-wave amplitude modulation (AM). The speech tokens were filtered into 2, 4, 8, or 16 contiguous log-spaced frequency bands spanning 0.1 to 10 kHz. Bands were then modulated, with the pattern of that AM being either coherent across bands or 180° out of phase for adjacent bands. In the out-of-phase conditions the odd-numbered bands had coherent phase AM and the even bands had coherent phase AM, but the AM pattern across these two subsets of bands were out of phase. Results from these two conditions, along with further conditions employing only modulated even- or odd-numbered bands, allowed performance to be compared between stimuli characterized by synchronous and asynchronous cues. Results indicate that observers are able to utilize asynchronously presented cues to consonant identification efficiently across a range of conditions.
Integration of outer hair cell activity in a one-dimensional cochlear model
Authors: Cohen Azaria , Furst Miriam
Published: April 2004

Recently, significant progress has been made in understanding the contribution of the mammalian cochlear outer hair cells (OHCs) to normal auditory signal processing. In the present paper an outer hair cell model is incorporated in a complete, time-domain, one-dimensional cochlear model. The two models control each other through cochlear partition movement and pressure. An OHC gain (γ) is defined to indicate the outer hair cell contribution at each location along the cochlear partition. Its value ranges from 0 to 1: γ=0 represents a cochlea with no active OHCs, γ=1 represents a nonrealistic cochlea that becomes unstable at resonance frequencies, and γ=0.5 represents an ideal cochlea. The model simulations reveal typical normal and abnormal excitation patterns according to the value of γ. The model output is used to estimate normal and hearing-impairment audiograms. High frequency loss is predicted by the model, when the OHC gain is relatively small at the basal part of the cochlear partition. The model predicts phonal trauma audiograms, when the OHC gain is random along the cochlear partition. A maximum threshold shift of about 60 dB is obtained at 4 kHz.