bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dispersion of a passive solute in non-ergodic transport by steady velocity fields in heterogeneous formations
Authors: Dagan Gedeon 
Published: April 2006

An inert solute is convected by a steady random velocity field, which is associated with flow through a heterogeneous porous formation. The log conductivity and the velocity are stationary random space functions. The log conductivity Y is assumed to be normal, with an isotropic two-point correlation of variance σY2 and of finite integral scale I. The solute cloud is of a finite input zone of lengthscale l. The transport is characterized with the aid of the spatial moments of the solute body. The effective dispersion coefficient is defined as half of the rate of change with time of the second spatial moment with respect to the centroid. Under the ergodic hypothesis, which is bound to be satisfied for l/I [Gt ] 1, the centroid moves with the mean velocity U and the longitudinal dispersion coefficient [dscr ]L tends to its constant, Fickian, limit. Under a Lagrangian first-order analysis in σY2 it has been found that [dscr ]L = σY2UI.This study addresses the computation of the effective longitudinal dispersion coefficient for a finite input zone, for which ergodic conditions may not be satisfied. In this case the centroid trajectory and the second spatial moments are random variables. In line with a previous work (Dagan 1990) the effective dispersion coefficient DL is defined as half the rate of change of the expected value of the second spatial moment for large transport time. The aim of the study is to derive DL and its dependence upon l/I and in particular to determine the conditions under which it tends to the ergodic limit [dscr ]L. The computation is carried out separately for a thin body aligned with the mean flow and one transverse to it. In the first case it is found that DL is equal to zero, i.e. the streamlined body does not disperse in the mean. This result is explained by the correlation between the trajectories of the leading and trailing edges, respectively, once the latter reaches the position of the first. The relatively modest increase of the mean second spatial moment is effectively computed. In the case of a thin body initially transverse to the mean flow, DL may reach the ergodic limit [dscr ]L for a ratio l/I of the order 102. For smaller values, DL is found to be bounded from above, and its maximum depends on l but not on I. The uncertainty caused by the randomness of the velocity field is manifested in the trajectory of the centroid rather than in the effective dispersion.
The effect of jet injection geometry on two-dimensional momentumless wakes
Authors: Park W. J. , Cimbala J. M. 
Published: April 2006

It is shown experimentally that a two-dimensional momentumless wake is strongly dependent on the jet injection configuration of the model. Namely, the decay rate of mean velocity overshoot ranged fromx−0.92tox−2.0for three different configurations, while the spreading rate ranged fromx0.3tox0.46for those same configurations. The magnitude of axial turbulence intensity was also found to depend on model configuration. On the other hand, the rate of decay of axial turbulence intensity was the same (x−0.81) for all three models. In all cases the mean shear and Reynolds stress decayed rapidly, leaving nearly isotropic turbulence beyond 30 or 40 model diameters.Appropriate length- and velocity scales are identified which normalize the mean velocity profiles into self-similar form. The shape of the normalized profile, however, was different for each configuration, indicating again that the initial conditions are felt very far downstream.
Internal wave generation in uniformly stratified fluids. Part 1. Green's function and point sources
Authors: Voisin Bruno 
Published: April 2006

In both Boussinesq and non-Boussinesq cases the Green's function of internal gravity waves is calculated, exactly for monochromatic waves and asymptotically for impulsive waves. From its differentiation the pressure and velocity fields generated by a point source are deduced. by the same method the Boussinesq monochromatic and impulsive waves radiated by a pulsating sphere are investigated.Boussinesq monochromatic waves of frequency ω < N are confined between characteristic cones θ = arccos(ω/N) tangent to the source region (N being the buoyancy frequency and θ the observation angle from the vertical). In that zone the point source model is inadequate. For the sphere an explicit form is given for the waves, which describes their conical 1/r½ radial decay and their transverse phase variations.Impulsive waves comprise gravity and buoyancy waves, whose separation process is non-Boussinesq and follows the arrival of an Airy wave. As time t elapses, inside the torus of vertical axis and horizontal radius 2Nt/β for gravity waves and inside the circumscribing cylinder for buoyancy waves, both components become Boussinesq and have wavelengths negligible compared with the scale height 2/β of the stratification. Then, gravity waves are plane propagating waves of frequency N cos θ, and buoyancy waves are radial oscillations of the fluid at frequency N; for the latter, initially propagating waves comparable with gravity waves, the horizontal phase variations have vanished and the amplitude has become insignificant as the Boussinesq zone has been entered. In this zone, outside the torus of vertical axis and horizontal radius Nta, a sphere of radius a [Lt ] 2/β is compact compared with the wavelength of the dominant gravity waves. Inside the torus gravity waves vanish by destructive interference. For the remaining buoyancy oscillations the sphere is compact outside the vertical cylinder circumscribing it, whereas the fluid is quiescent inside this cylinder.
Geographic Regional Differences in Rocuronium Bromide Dose–Response Relation and Time Course of Action
Authors: Dahaba Ashraf A. , Perelman Seth I. , Moskowitz David M. , Bennett Henry L. , Shander Aryeh , Xiao Zhaoyang , Huang Lin , An Gang , Bornemann Helmar , Wilfinger Georg , Hager Barbara , Rehak Peter H. , List Werner F. , Metzler Helfried 
Published: April 2006

Background
Geographic location is not acknowledged as a stratifying factor that can directly affect drug potency, because drugs are still licensed with the same recommended dose for different geographic regions. The aim of the current study was to compare the potency and duration of action of rocuronium bromide in 54 patients in three countries with different life habits, diet, and ambient conditions, namely white Austrians, white North Americans, and Han Chinese in China.

Methods
Neuromuscular block of six consecutive 50-microg/kg rocuronium incremental doses followed by 300 microg/kg was evaluated using the Relaxometer mechanomyograph (Groningen University, Groningen, Holland). Dose-response curves were created using log-dose-probit transformation. The authors compared rocuronium bromide ED50, ED90, and ED95 (effective doses required for 50%, 90%, and 95% first twitch depression, respectively) as well as Dur25 and Dur0.8 (times from last incremental dose administration until 25% first twitch and 0.8 train-of-four ratio recovery, respectively) in patients of the three countries.

Results
Rocuronium ED50, ED90, and ED95 were significantly higher in Austrian patients (258 +/- 68, 530 +/- 159, and 598 +/- 189 microg/kg) and Chinese patients (201 +/- 59, 413 +/- 107, and 475 +/- 155 microg/kg) compared with American patients (148 +/- 48, 316 +/- 116, and 362 +/- 149 microg/kg, respectively). Dur25 and Dur0.8 were significantly shorter in Austrian patients (22.3 +/- 5.5 and 36.9 +/- 12.8 min) and Chinese patients (30.4 +/- 7.5 and 45.7 +/- 15.9 min) compared with American patients (36.7 +/- 8.5 and 56.2 +/- 16.7 min, respectively).

Conclusions
The authors demonstrated a significant difference in rocuronium potency and duration of action among patients in the three countries. Larger studies are required for determining dosage recommendations for different geographic regions.
Propofol Decreases Myofilament Ca2+Sensitivity via a Protein Kinase C–, Nitric Oxide Synthase–dependent Pathway in Diabetic Cardiomyocytes
Authors: Wickley Peter J. , Shiga Toshiya , Murray Paul A. , Damron Derek S. 
Published: April 2006

Background
The authors' objective was to assess the role of protein kinase C (PKC) and nitric oxide synthase (NOS) in mediating the effects of propofol on diabetic cardiomyocyte contractility, intracellular free Ca2+ concentration ([Ca2+]i), and myofilament Ca2+ sensitivity.

Methods
Freshly isolated ventricular myocytes were obtained from normal and diabetic rat hearts. [Ca2+]i and cell shortening were simultaneously measured in electrically stimulated, ventricular myocytes using fura-2 and video-edge detection, respectively. Actomyosin adenosine triphosphatase activity and troponin I (TnI) phosphorylation were assessed in [32P]orthophosphate-labeled myofibrils. Western blot analysis was used to assess expression of PKC and NOS.

Results
Propofol (10 microM) decreased peak shortening by 47 +/- 6% with little effect on peak [Ca2+]i (92 +/- 5% of control) in diabetic myocytes. Maximal actomyosin adenosine triphosphatase activity was reduced by 43 +/- 7% and TnI phosphorylation was greater (32 +/- 6%) in diabetic myofibrils compared with normal. Propofol reduced actomyosin adenosine triphosphatase activity by 17 +/- 7% and increased TnI phosphorylation in diabetic myofibrils. PKC inhibition prevented the propofol-induced increase in TnI phosphorylation and decrease in shortening. Expression of PKC-alpha, PKC-delta, PKC-epsilon, and constitutive NOS were up-regulated and inducible NOS was expressed in diabetic cardiomyocytes. NOS inhibition attenuated the propofol-induced decrease in shortening.

Conclusion
Myofilament Ca2+ sensitivity and, to a lesser extent, peak [Ca2+]i are decreased in diabetic cardiomyocytes. Increases in PKC and NOS expression in combination with TnI phosphorylation seem to contribute to the decrease in [Ca2+]i and myofilament Ca2+ sensitivity. Propofol decreases [Ca2+]i and shortening via a PKC-, NOS-dependent pathway.
Long‐Term Clinical Outcome in Patients With Congenital Chloride Diarrhea
Authors: Hihnala Satu , Höglund Pia , Lammi Laura , Kokkonen Jorma , Örmälä Timo , Holmberg Christer 
Published: April 2006

ABSTRACTObjectives:Congenital chloride diarrhea (CLD) is a rare, autosomal recessive disorder of intestinal Cl−/HCO3− exchange caused by mutations in the SLC26A3 gene and characterized by persistent Cl− rich diarrhea from birth. Treatment is symptomatic and replacement therapy with NaCl and KCl has been shown to be effective in children, but the long‐term prognosis remains unclear. We studied the largest known cohort of patients to evaluate the long‐term outcome of CLD and to search for extraintestinal manifestations.Methods:This is a cross‐sectional clinical evaluation and retrospective analysis of medical history of 36 Finnish patients with CLD, born in the 1960s (n = 8), 1970s (n = 7) and 1980s (n = 21).Results:Early diagnosis and aggressive salt replacement therapy were associated with normal growth and development, in addition to significantly reduced mortality rates among the groups of patients born in the different decades, respectively (P = 0.001). No deaths due to CLD were observed after 1972. Enuresis, slight soiling and hospitalizations for gastroenteritis were common, especially in childhood, but 92% of the patients found their health excellent or good. Complications documented were end‐stage renal disease (n = 1) and hyperuricemia (n = 4), novel findings possibly associated with CLD being male subfertility (n = 3), spermatoceles (n = 3), intestinal inflammation (n = 2), inguinal hernias (n = 4) and increased concentrations of sweat Cl− in 12% of the patients.Conclusions:When early diagnosed and adequately treated, the long‐term prognosis of CLD is favorable. A putative role of a primary anion exchange defect of SLC26A3 in male subfertility and the decline of renal function due to chronic dehydration deserve further characterization.
Systemic Vasculitis
Authors: Brogan P. A. , Malik M. , Shah N. , Kilday J. P. , Ramsay A. , Shah V. , Murch S. H. , Thomson M. A. , Walker‐Smith J. A. , Lindley K. J. , Milla P J. , Dillon M. J. 
Published: April 2006

ABSTRACTObjectives:Indeterminate intestinal inflammation may result from a variety of inflammatory conditions in addition to ulcerative colitis and Crohn disease. The primary systemic vasculitides may present with intestinal inflammation and an indeterminate colitis. We set out to describe a series of children with primary systemic vasculitis who initially presented with clinical features suggestive of inflammatory bowel disease (IBD) to establish criteria that might help discriminate between IBD and primary systemic vasculitis.Methods:Ten children (6 boys, median age at presentation 8.9 years, range 0.9‐14.5 years) satisfied inclusion criteria.Results:All had abdominal pain, weight loss, diarrhea (6 of 10 bloody) and laboratory evidence of a severe acute phase response. Extraintestinal clinical features included vasculitic rash, renal impairment, myalgia, testicular pain and polyarthritis. Endoscopy showed vascular changes or other macroscopic findings suggestive of vasculitis in 5 of 10 patients. Gut histology revealed indeterminate chronic inflammatory mucosal changes and one patient with small artery fibrinoid necrosis in the submucosal vessels. Extraintestinal biopsy was performed in 6 patients and had a higher yield for the demonstration of vasculitis than intestinal biopsy. The results of selective visceral angiography was suggestive of vasculitis in all patients, but was normal in 7 cases of treatment‐unresponsive classic IBD. Treatment comprised corticosteroid and azathioprine in all patients. Cyclophosphamide was given to 7 of 10 patients.Conclusions:Extraintestinal manifestations and inflammatory responses that may be disproportionate to the degree of intestinal inflammation provide clues to the presence of an underlying primary systemic vasculitis, and these data suggest that selective visceral angiography plays a key role in the diagnosis of vasculitis in this context. It is important to identify and treat any vasculitic component because failure to do so may result in consequential morbidity or mortality.
2005 Emil Thomas Kaiser Award
Authors: Raines Ronald T. 
Published: April 2006

AbstractCollagen is the most abundant protein in animals. The conformational stability of the collagen triple helix is enhanced by the hydroxyl group of its prevalent (2S,4R)‐4‐hydroxyproline residues. For 25 years, the prevailing paradigm had been that this enhanced stability is due to hydrogen bonds mediated by bridging water molecules. We tested this hypothesis with synthetic collagen triple helices containing 4‐fluoroproline residues. The results have unveiled a wealth of stereoelectronic effects that contribute markedly to the stability of collagen, as well as other proteins. This new understanding is leading to synthetic collagens for a variety of applications in biotechnology and biomedicine.
Association of a Glu92Lys substitution in MC1R with extended brown in Japanese quail (Coturnix japonica)
Authors: Nadeau N. J. , Minvielle F. , Mundy N. I. 
Published: April 2006

SummaryWe investigated melanocortin 1 receptor (MC1R) as a candidate locus for the Extended brown phenotype in quail, in which there is a general darkening throughout the plumage. An initial screen of variation in MC1R in Extended brown and in wild‐type quails revealed two polymorphic non‐synonymous sites. One of these sites, a G‐to‐A substitution leading to a Glu92Lys mutation, was perfectly associated with plumage phenotype; all Extended brown birds were homozygous for Lys92. Co‐segregation of the Glu92Lys mutation with the Extended brown phenotype was confirmed in 24 progeny of an E/e+ × E/e+ cross. Glu92Lys is likely to be the causative mutation for the increased melanism in Extended brown, given that the same mutation is associated with melanic plumage in many breeds of domestic chicken, as well as in a wild passerine bird (the bananaquit, Coereba flaveola) and laboratory mice. Interestingly, the increase in melanization with the Glu92Lys mutation is less marked in quails than in most other birds and mammals. Phylogenetic results indicate that the Glu92Lys mutation has independently occurred in quail and chicken lineages.
The effect of aprotinin on activated protein C‐mediated downregulation of endogenous thrombin generation
Authors: Tanaka Kenichi A. , Szlam Fania , Levy Jerrold H. 
Published: April 2006

SummaryThrombin plays a central role in coagulation and haemostasis. Binding of thrombin to thrombomodulin generates activated protein C (APC), which exerts a negative feedback on thrombin formation. Aprotinin, a natural proteinase inhibitor is used extensively during cardiac surgery because this procedure is often associated with profound activation of coagulation and inflammatory pathways. Some in vitro evidences suggest that aprotinin inhibits APC, but the clinical relevance is unclear. The recombinant human soluble thrombomodulin (rhsTM)‐modified thrombin generation (TG) assay was used to investigate the effects of aprotinin on APC in plasma samples obtained from healthy volunteers, aprotinin‐treated cardiac surgical patients and in protein C (PC)‐depleted plasma. Based on the results of in vitro TG assay, addition of rhsTM (0·75–3·0 μg/ml) to volunteer or patient platelet‐poor plasma significantly reduced (70·8 ± 21·9 and 95·3% ± 4·6%, respectively) thrombin formation when compared with PC‐depleted plasma (8·3% ± 5·2%). Aprotinin (100–200 KIU) caused a small, statistically insignificant decrease in the peak thrombin formation in normal and PC‐deficient plasma (12·0 ± 6·1%). In cardiac surgical patients, levels of functional PC, factor II, antithrombin and platelet significantly decreased after cardiopulmonary bypass (CPB). Soluble thrombomodulin concentrations were increased after CPB (3·5 ± 2·2 to 5·0 ± 2·2 ng/ml), but they were still within the normal range for human plasma. Our results showed that, even though endogenous PC level is decreased after CPB, it retains its activity in the presence of thrombomodulin, and aprotinin has limited inhibitory effect on APC generation.
Intraspecific variation in survival and mitochondrial oxidative phosphorylation in wild‐caught Drosophila simulans
Authors: Melvin Richard G. , Ballard J. William O. 
Published: April 2006

SummaryLifespans of organisms vary greatly even among individuals of the same species. Under the framework of the free oxygen radical theory of aging, it is predicted that variation in individual lifespan within a species will correlate with variation in the accumulation of oxidative damage to cell components from reactive oxygen species. In this study we test the hypothesis that variation in survival of three wild‐caught Drosophila simulans fly lines (HW09, NC48 and MD106) correlates with three key aspects of mitochondrial bioenergetics. The rank order of median survival was HW09 > MD106 > NC48. Young HW09 flies (11–18 days) had (i) highest ADP:O (quantity of oxygen consumed by mitochondria when provided with a quantity of ADP) when metabolizing both electron transport chain complex I and complex III substrates; (ii) lowest rate of mitochondrial hydrogen peroxide production from complex III; and (iii) highest cytochrome c oxidase activity from complex IV. Rate of hydrogen peroxide production increased and cytochrome c oxidase activity decreased in all lines in the age range 11–25 days. This is the first study to correlate natural variation in organism survival with natural variation in mitochondrial bioenergetics.
Interplay of Efflux System,
ampC
, and
oprD
Expression in Carbapenem Resistance of
Pseudomonas aeruginosa
Clinical Isolates
Authors: Quale John , Bratu Simona , Gupta Jyoti , Landman David 
Published: April 2006

ABSTRACT

Carbapenems are important agents for the therapy of infections due to multidrug-resistant
Pseudomonas aeruginosa
; the development of carbapenem resistance hampers effective therapeutic options. To assess the mechanisms leading to resistance, 33 clinical isolates with differing degrees of carbapenem susceptibility were analyzed for the expression of the chromosomal β-lactamase (
ampC
), the porin that is important for the entry of carbapenems (
oprD
), and the proteins involved in four efflux systems (
mexA
,
mexC
,
mexE
, and
mexX
). Real-time reverse transcriptase PCR was performed using primers and fluorescent probes for each of the target genes. The sequencing of regulatory genes (
ampR
,
mexR
,
nalC
,
nalD
,
mexT
, and
mexZ
) was also performed. Diminished expression of
oprD
was present in all imipenem- and meropenem-resistant isolates but was not required for ertapenem resistance. Increased expression of
ampC
was not observed in several isolates that were overtly resistant to carbapenems. Increased expression of several efflux systems was observed in many of the carbapenem-resistant isolates. Increased efflux activity correlated with high-level ertapenem resistance and reduced susceptibility to meropenem and aztreonam. Most isolates with increased expression of
mexA
had mutations affecting
nalC
and/or
nalD
. Two isolates with mutations leading to a premature stop codon in
mexZ
had markedly elevated
mexX
expressions, although mutations in
mexZ
were not a prerequisite for overexpression. β-Lactam resistance in clinical isolates of
P. aeruginosa
is a result of the interplay between diminished production of
oprD
, increased activity of
ampC
, and several efflux systems.
Calcium Signals Are Affected by Ciprofloxacin as a Consequence of Reduction of Mitochondrial DNA Content in Jurkat Cells
Authors: Kozieł Rafał , Zabłocki Krzysztof , Duszyński Jerzy 
Published: April 2006

ABSTRACT

The effects of ciprofloxacin on mitochondrial DNA (mtDNA) content, oxygen consumption, mitochondrial membrane potential, cellular ATP formation, and capacitative Ca
2+
entry into Jurkat cells were investigated. In cells incubated for several days with 25 μg/ml ciprofloxacin, a 60% reduction of mtDNA content, inhibition of the respiratory chain, and a significant decrease in mitochondrial membrane potential were observed. These changes led to a decrease in the calcium buffering capacity of mitochondria which, in turn, resulted in a gradual inhibition of the capacitative Ca
2+
entry. On days 4, 7, and 11 of incubation with ciprofloxacin, the initial rates of Ca
2+
entry were reduced by 33%, 50%, and 50%, respectively. Ciprofloxacin caused a transient decrease in the cellular capability for ATP formation. In cells incubated for 15 min with glucose, pyruvate, and glutamine as exogenous fuel, ciprofloxacin reduced ATP content by 16% and 35% on days 4 and 7, respectively, of incubation with the drug. However, on day 11 of incubation with ciprofloxacin, a recovery of cellular ATP formation was observed. In conclusion, long-term exposure of Jurkat cells to ciprofloxacin at a concentration of 25 μg/ml seriously affects cellular energy metabolism and calcium homeostasis.
Extended-Spectrum β-Lactamases and Plasmid-Mediated AmpC Enzymes among Clinical Isolates of
Escherichia coli
and
Klebsiella pneumoniae
from Seven Medical Centers in Taiwan
Authors: Yan Jing-Jou , Hsueh Po-Ren , Lu Jang-Jih , Chang Feng-Yee , Shyr Jainn-Ming , Wan Jen-Hsien , Liu Yung-Ching , Chuang Yin-Ching , Yang Yi-Chueh , Tsao Shih-Ming , Wu Hsiu-Hung , Wang Li-Shin , Lin Tsuey-Pin , Wu Hsiu-Mei , Chen Hung-Mo , Wu Jiunn-Jong 
Published: April 2006

ABSTRACT

Production of extended-spectrum β-lactamases and plasmid-mediated AmpC enzymes was investigated among 291
Escherichia coli
and 282
Klebsiella pneumoniae
isolates that showed decreased susceptibilities to extended-spectrum cephalosporins from seven Taiwanese medical centers. CTX-M-type and SHV-type enzymes were the most prevalent extended-spectrum β-lactamases. CMY-2-like and DHA-1-like β-lactamases were the most prevalent AmpC-type enzymes.