bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of perfluorooctanoic acid and perfluorooctanesulfonate in human tissues by liquid chromatography/single quadrupole mass spectrometry
Authors: Maestri Luciano , Negri Sara , Ferrari Massimo , Ghittori Sergio , Fabris Francesca , Danesino Paolo , Imbriani Marcello 
Published: August 2006

AbstractA method is described that permits the measurement of the levels of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) in human liver, kidney, adipose tissue, brain, basal ganglia, hypophysis, thyroid, gonads, pancreas, lung, skeletal muscle and blood, even in subjects not occupationally exposed to these compounds. The purification of samples involved the use of trifunctional (tC18) and strong anion‐exchange (SAX) solid‐phase extraction cartridges, and the analysis utilized a high‐performance liquid chromatograph coupled to a single quadrupole mass spectrometer (LC/MS). The analyses were conducted on a mixed‐bed reversed‐phase column by gradient runs using 3 mM ammonium acetate/methanol mixtures at different proportions as the mobile phase. The detector was used in electrospray negative ion mode by recording simultaneously the ions m/z 413.0 (PFOA) and 499.0 (PFOS). Perfluorononanoic acid (PFNA), added to the samples before the purification, was used as the internal standard (ion monitored = m/z 463.6). The recovery rates of the extraction procedure ranged from 79.6 to 95.6% (CV% 1.7–7.4%) for PFOA, from 79.7 to 100.8% (CV% = 1.2–7.1) for PFOS, and from 89.1 to 102.3% (CV% = 0.9–5.2 %) for PFNA. The calibration curves were linear up to at least 400 ng of analytes per gram of tissue. The detection limits (signal‐to‐noise ratio = 3) were 0.1 ng/g for both PFOA and PFOS measured in all tissues except adipose tissue, where the limits were about 0.2 ng/g. The content of analytes in tissues varied from 0.3 to 3.8 ng/g (respectively: basal ganglia and lung) for PFOA, and from 1.0 to 13.6 ng/g (respectively: skeletal muscle and liver) for the linear isomer of PFOS. The method is suitable to evaluate the content of PFOA and PFOS in different tissues taken from the general population exposed to very low concentrations of these pollutants. Copyright © 2006 John Wiley & Sons, Ltd.
Negative gas‐phase ion chemistry of silane: a quadrupole ion trap study
Authors: Operti Lorenza , Rabezzana Roberto , Vaglio Gian Angelo 
Published: August 2006

AbstractSilicon clusters are of considerable interest for their importance in astrophysics and chemical vapour deposition processes, as well as from a fundamental point of view. Here, we present a quadrupole ion trap study of the self‐condensation ion/molecule reactions of anions of silane. In the high‐pressure regime, several ion clusters are formed with increasing size: the largest ions detected are Si5H (n = 0–3). Selective ion isolation and storage allowed detection of the main reaction sequences occurring in the reacting system. The most frequent condensation step is followed by single or multiple dehydrogenation, this latter being particularly observed for the high‐mass reactant ions. As a consequence, the most abundant ions in the mass spectra are those with a low content of hydrogen, namely Si2H−, Si3H−, and Si4H−. These results are discussed with reference to literature data on silicon cluster anions and related systems. Copyright © 2006 John Wiley & Sons, Ltd.
Perceived stress, psychological well‐being and the activity of neutrophils in patients undergoing cardiopulmonary bypass surgery
Authors: Ellard D.R. , Barlow J.H. , Mian R. , Patel R. 
Published: August 2006

AbstractThis study explored relationships, before and after surgery, between perceived stress and the activity of white‐blood cells (neutrophils) in 82 patients undergoing heart surgery involving cardiopulmonary bypass surgery (CPB).On the evening before surgery and at follow‐up, 6‐weeks after discharge, patients completed self‐administered standard psychological measures. Small peripheral blood samples were taken, from which neutrophil activity was quantified using nitro‐blue tetrazolium (NBT) and luminol‐dependant chemiluminescence (phagocytic capacity).There were consistent, statistically significant associations between stress and percentageNBT cells at baseline and at follow‐up. Regression analysis showed that perceived stress was a predictor of neutrophil activity at follow‐up suggesting that higher levels of stress are associated with higher levels of activity. Results from the phagocytic capacity data support and strengthen the NBT findings; in response to stimuli the phagocytic capacity of the neutrophils is reduced at baseline (high stress) and increased at follow‐up (lower stress). Significant decreases were found on perceived stress, anxiety, depression, negative affect and health‐related stress at follow‐up. Patients' self‐efficacy was high at baseline and remained high throughout the study.Results highlighted a consistent, significant relationship between perceived stress and the ‘activity’ of neutrophils. The implications of this finding are worthy of exploration given that stress‐activated neutrophils may adversely influence health outcomes. Copyright © 2006 John Wiley & Sons, Ltd.
Self‐focused attention and self‐monitoring influence on health and coping with stress
Authors: Huflejt‐ukasik Mirosawa , Czarnota‐Bojarska Joanna 
Published: August 2006

AbstractThe issue of the presented study was to find relations between the elements of self‐focused attention, self‐monitoring and different styles of coping with stress and psychosomatic symptoms.The two factors of self‐focused attention must be considered: (1) the private self‐consciousness, the tendency to be aware of those aspects of one's own self which cannot be observed by others; (2) the public self‐consciousness, the tendency to be aware of the publicly displayed aspects of the self.The level of self‐monitoring determines the significance which a person attaches to indicators coming from his or her social surrounding while modifying and shaping his or her behaviour.The results indicate both similarities and differences within the scope of both constructs: self‐monitoring and self‐focused attention. The differences between the constructs in question also pertain to their relation with psychopathology. Copyright © 2006 John Wiley & Sons, Ltd.
Work–family interference as a mediator between job demands and job burnout among doctors
Authors: Montgomery Anthony J. , Panagopolou Efharis , Benos Alexis 
Published: August 2006

AbstractThere is an increasing realization that the connections between work and family life are of critical importance in contemporary society. The present study examined the relationship between job demands and burnout, and the mediational role of work–family interference (WFI) in a sample of Greek doctors (N = 162). The main findings are: (1) emotional job demands were found to be a strong independent predictor of both emotional exhaustion and depersonalization; (2) quantitative job demands were found to predict emotional exhaustion; (3) WFI was found to partially mediate the relationship between both quantitative/emotional job demands and emotional exhaustion; (4) additionally, WFI partially mediated the relationship between emotional job demands and depersonalization. The results and limitations are discussed with reference to the medical profession. Copyright © 2006 John Wiley & Sons, Ltd.
Multistage growth and reworking of the Palaeoproterozoic crust in the Bergslagen area, southern Sweden: evidence from U–Pb geochronology
Authors: ANDERSSON ULF B. , HÖGDAHL KARIN , SJÖSTRÖM HÅKAN , BERGMAN STEFAN 
Published: August 2006

The Svecofennian Domain of the Fennoscandian Shield constitutes a considerable volume of Palaeoproterozoic crustal growth, 2.1–1.86 Ga ago, in between the Archaean craton in the NE and the 1.85–1.65 Ga Transscandinavian Igneous Belt (TIB) in the south and west. The Bergslagen area is a classical ore province located in the southwestern part of the Svecofennian Domain of south-central Sweden. Its northern part is dominated by volcanic and plutonic rocks of a magmatic arc with continental affinity, while the SE part is made up by a sedimentary basin. The Bergslagen area shows a metamorphic zonation from lower to middle amphibolite facies in the north to upper amphibolite facies and locally granulite facies in the south; a small greenschist area exists in the west. Identifying the age spectra of inherited components, magmatic crystallization, as well as metamorphic episodes, provide important constraints on the geodynamic evolution of this centrally located piece of the Shield.U–Pb zircon SIMS data presented in this paper complement the previous, regionally scattered TIMS data from this area. Magmatic zircons from two felsic metavolcanic rocks and two amphibolites (metagabbros) yield 1888±12, 1892±7 and 1887±5, 1895±5 Ma, respectively; i.e. within the 1.91–1.86 Ga range previously obtained for Early Svecofennian magmatism in Bergslagen. An augen gneiss from southern Bergslagen, assigned to the earliest TIB generation, yield an intrusive age of 1855±6 Ma. Metamorphic monazites from the same rock indicate that deformation and elevated thermal activity prevailed 1.83–1.82 Ga ago (TIMS). Metamorphic zircons in high-grade metasedimentary rocks from the south and west yield ages of 1793±5 and 1804±10 Ma, in accordance with ages for regional peak metamorphism and migmatite formation found elsewhere in the southern Svecofennian province of Sweden. More importantly, a few zircon crystals and overgrowths in rocks from the north indicate an early metamorphic episode at c. 1.87 Ga, indicating that Bergslagen has experienced two major metamorphic events. Detrital and inherited zircons span the range 2.78–1.90 Ga, with an apparent gap at 2.45–2.1 Ga, which further emphasize previous observations of a major juvenile (<2.1 Ga) and a minor Archaean provenance. This, and in particular the 1.94–1.91 Ga crystals present in the c. 1.89 Ga amphibolites, support the suggestion of a former Palaeoproterozoic pre-1.91 Ga crust in the Bergslagen area.
Vortex formation in a non-uniform self-gravitating dusty magnetoplasma
Authors: IJAZ AISHA , MIRZA ARSHAD M. , AZEEM M. 
Published: August 2006

AbstractThe dynamics of low-frequency, short-wavelength electrostatic (SWES) drift waves in a self-gravitating, non-uniform, collisional dusty magnetoplasma with equilibrium dust-velocity gradients is studied in the present work. By employing the dust continuity and momentum equations to describe the dust dynamics and Boltzmann distribution for the electrons and ions, we have derived a new set of nonlinear mode coupling equations. In the linear limit, it is found that SWES drift waves are subjected to dissipative instability in the presence of an equilibrium dust sheared flow and self-gravitation effect. On the other hand, in the nonlinear case, it is shown that possible stationary solutions of the nonlinear equations are dipolar vortices.
Covariant form for the collision integral
Authors: MELROSE D. B. 
Published: August 2006

AbstractThe collision integral that describes the evolution of a distribution of particles in a plasma due to Coulomb interactions between themselves or with other particles is generalized to include relativistic effects and the current–current interaction (in addition to the charge–charge interaction). This is achieved through a covariant version of a conventional derivation based on correlation functions for fluctuations in the plasma. The covariant theory is used to distinguish between longitudinal (charge–charge) and transverse (current–current) interactions. For highly relativistic particles, the current–current contribution is half the charge–charge contribution when Debye screening is unimportant, and is unaffected by Debye screening. It is shown that the classical theory is reproduced by a quantum electrodynamics calculation for electron–electron (Møller) scattering in the limit of small momentum transfer.
Inhibition of L‐type calcium current by propafenone in single myocytes isolated from the rabbit atrioventricular node
Authors: Hancox Jules C , Mitcheson John S 
Published: August 2006

The atrioventricular node (AVN) is an important part of the conduction system in the heart and is a significant site of antiarrhythmic drug action. The class 1 antiarrhythmic propafenone is effective in treating a variety of arrhythmias, including those involving the AVN. In this study, we have investigated the effects of propafenone on ionic currents in single rabbit AVN cells, focusing in particular on those on L‐type calcium current (ICa, L).
With a standard K‐based internal dialysis solution, exposure to 5 μM propafenone reduced significantly the amplitude of ICa, L. In spontaneously active AVN myocytes, action potential upstroke velocity was decreased by propafenone exposure, consistent with the observed change in ICa, L.
By use of a Cs‐based internal dialysis solution to record ICa, L selectively, voltage clamp test pulses were applied from a holding potential of −40 mV to +10 mV (stimulation frequency 0.33 Hz). Propafenone 5 μM reduced mean ICa, L density at +10 mV from −9.58±1.05 pA/pF to −4.19±0.60 pA/pF (P<0.002). A range of propafenone concentrations were applied which reduced ICa, L in a dose‐dependent manner (IC50 1.7 μM). When test pulses were applied to a range of potentials, propafenone reduced ICa, L at each potential without significantly affecting the activation curve for this current. Thus, propafenone reduced ICa, L conductance, without affecting the voltage‐dependent activation properties of the current.
ICa, L block by propafenone exhibited tonic‐, use‐ and frequency‐dependent characteristics.
In the presence of propafenone, the voltage‐dependence of inactivation of ICa, L was shifted 8 mV in the hyperpolarizing direction. Also, the recovery of ICa, L from inactivation was slowed by propafenone.
The ICa, L blocking properties of propafenone may mediate some of the antiarrhythmic properties of this agent, particularly in regions of the heart such as the AVN in which ICa, L contributes significantly to the action potential upstroke.

British Journal of Pharmacology (1997) 121, 7–14; doi:10.1038/sj.bjp.0701086
Peptidergic modulation of the sympathetic contraction in the rabbit ear artery: effects of temperature
Authors: Padilla J , García‐Villalón A L , Monge L , García J L , Fernández N , Gomez B , Dieguez G 
Published: August 2006

The effects of neuropeptide Y, endothelin‐1, arginine‐vasopressin and angiotensin II on the vascular contraction to sympathetic nerve stimulation were studied in isolated segments, 2 mm long, from the rabbit central ear artery, a cutaneous vessel, during changes in temperature (24°–41°C).
Transmural electrical stimulation (1–8 Hz, at supramaximal voltage) produced frequency‐dependent contraction, and this response, partially blocked by tetrodotoxin (1 μM) and phentolamine (1 μM), was reduced by cooling (30°C–24°C) and was not modified by warming (41°C), as compared to that recorded at 37°C.
Pretreatment with neuropeptide Y (10, 30 and 100 nM) increased in a concentration‐dependent manner the vascular contraction to sympathetic stimulation at every temperature studied, but this potentiation was greater during cooling (34°C–24°C) than at 37°C or warming (41°C).
Pretreatment with endothelin‐1 (3 and 10 nM) or vasopressin (0.1, 0.3 and 1 nM) increased in a concentration‐dependent manner the vascular contraction to sympathetic stimulation during cooling (34°C–24°C), but not at 37°C or warming (41°C).
Pretreatment with angiotensin II (0.1, 0.3 and 1 μM) did not modify the contraction to sympathetic stimulation at any temperature studied.
These results suggest that neuropeptide Y, endothelin‐1 and vasopressin, but not angiotensin II, modulate the cutaneous vasoconstriction to sympathetic nerve stimulation by potentiating this vasoconstriction during cooling.

British Journal of Pharmacology (1997) 121, 21–28; doi:10.1038/sj.bjp.0701094
The interaction of diadenosine polyphosphates with P2X‐receptors in the guinea‐pig isolated vas deferens
Authors: Westfall T D , McIntyre C A , Obeid S , Bowes J , Kennedy C , Sneddon P 
Published: August 2006

The site(s) at which diadenosine 5′,5′′′‐P1, P4‐tetraphosphate (AP4A) and diadenosine 5′, 5′′′‐P1, P5‐pentaphosphate (AP5A) act to evoke contraction of the guinea‐pig isolated vas deferens was studied by use of a series of P2‐receptor antagonists and the ecto‐ATPase inhibitor 6‐N, N‐diethyl‐D‐β,γ‐dibromomethyleneATP (ARL 67156).
Pyridoxalphosphate‐6‐azophenyl‐2′,4′‐disulphonic acid (PPADS) (300 nM–30 μM), suramin (3–100 μM) and pyridoxal‐5′‐phosphate (P‐5‐P) (3–1000 μM) inhibited contractions evoked by equi‐effective concentrations of AP5A (3 μM), AP4A (30 μM) and α,β‐methyleneATP (α,β‐meATP) (1 μM), in a concentration‐dependent manner and abolished them at the highest concentrations used.
PPADS was more potent than suramin, which in turn was more potent than P‐5‐P. PPADS inhibited AP5A, AP4A and α,β‐meATP with similar IC50 values. No significant difference was found between IC50 values for suramin against α,β‐meATP and AP5A or α,β‐meATP and AP4A, but suramin was more than 2.5 times more potent against AP4A than AP5A. P‐5‐P showed the same pattern of antagonism.
Desensitization of the P2X1‐receptor by α,β‐meATP abolished contractions evoked by AP5A (3 μM) and AP4A (30 μM), but had no effect on those elicited by noradrenaline (100 μM).
ARL 67156 (100 μM) reversibly potentiated contractions evoked by AP4A (30 μM) by 61%, but caused a small, significant decrease in the mean response to AP5A (3 μM).
It is concluded that AP4A and AP5A act at the P2X1‐receptor, or a site similar to the P2X1‐receptor, to evoke contraction of the guinea‐pig isolated vas deferens. Furthermore, the potency of AP4A, but not AP5A, appears to be inhibited by an ecto‐enzyme which is sensitive to ARL 67156.

British Journal of Pharmacology (1997) 121, 57–62; doi:10.1038/sj.bjp.0701099
Inhibition by singlet molecular oxygen of the vascular reactivity in rabbit mesenteric artery
Authors: Mizukawa Hisae , Okabe Eiichiro 
Published: August 2006

The effects of reactive oxygen intermediates derived from photoactivated rose bengal on the vascular reactivity have been evaluated in rabbit mesenteric artery ring preparations. The artery rings were exposed to xanthene dye rose bengal (50 nM) illuminated (6,000 lux) at 560 nm for 30 min. Spin trapping studies with 2,2,6,6‐tetramethylpiperidine (TEMP) and 5,5‐dimethyl‐1‐pyrroline‐N‐oxide (DMPO) with electron spin resonance spectrometry were also conducted in solution (and not within tissues) to determine quantitatively the reactive oxygen species generated from photoactivated rose bengal.
Contraction of the ring preparations induced by noradrenaline (10−8 to 10−4 M) was attenuated by previous exposure to photolysed rose bengal; the observation that the pD2 decreased without a significant reduction in maximum tension generation is consistent with the view that receptor dysfunction may be involved in the effect of photolysed rose bengal.
Prior exposure to photolysed rose bengal of the ring preparations inhibited the endothelium‐dependent relaxation evoked by acetylcholine (10−6 M) and calcium ionophore A23187 (10−7 M), but not the endothelium‐independent relaxation evoked by nitroglycerin (10−6 M).
A variety of scavengers, superoxide dismutase (33 units ml−1), catalase (32 units ml−1) and 1,3‐dimethyl‐2‐thiourea (DMTU, 10 mM), which should eliminate the superoxide anion radical, H2O2 and the hydroxyl radical, had no effect on the attenuated responses to noradrenaline and acetylcholine induced by photolysed rose bengal. In contrast, the inhibition of the observed effect of photolysed rose bengal was obtained with addition of histidine (25 mM), a singlet molecular oxygen quencher.
It was found that photolysis of rose bengal from a 1:2:2:1 quartet, characteristic of the hydroxyl radical‐DMPO spin adduct, which was effectively blunted by DMTU, superoxide dismutase and catalase whereas histidine was ineffective. The results of the electron spin resonance study also showed that a singlet molecular oxygen was produced by photoactivation of rose bengal; this was detected as singlet oxygen‐TEMP product (TEMPO; 2,2,6,6‐tetramethylpiperidine‐N‐oxyl). The formation of the TEMPO signal was strongly inhibited by histidine, but not by DMTU, superoxide dismutase and catalase.
It is suggested that the superoxide anion radical, H2O2 and hydroxyl radical are formed in addition to singlet molecular oxygen, and the data obtained from the present study indicate that singlet molecular oxygen is one of the most destructive oxygen species. Endothelium‐dependent relaxation is quite vulnerable to singlet molecular oxygen. Singlet oxygen also depresses noradrenaline‐induced contraction possibly via α‐adrenoceptor dysfunction. This, in turn, may lead to vascular incompetence.

British Journal of Pharmacology (1997) 121, 63–70; doi:10.1038/sj.bjp.0701103
Measurement of GABAA receptor function in rat cultured cerebellar granule cells by the Cytosensor microphysiometer
Authors: Brown Maria J , Wood Martyn D , Coldwell Martyn C , Bristow David R 
Published: August 2006

γ‐Aminobutyric acid (GABA), acting via the GABAA receptor, increased the extracellular acidification rate of rat primary cultured cerebellar granule cells, measured by the Cytosensor microphysiometer.
The optimal conditions for the measurement of GABAA receptor function in cerebellar granule cells by microphysiometry were: cells seeded at 9–12×105 cells/transwell cup and maintained in vitro for 8 days, GABA stimulation performed at 25°C, with a stimulation time of 33 s.
GABA stimulated a concentration‐dependent increase in the extracellular acidification rate with an EC50 of 2.0±0.2 μM (mean±s.e.mean, n=7 experiments) and maximal increase (Emax) over basal response of 15.4±1.2%.
The sub‐maximal GABA‐stimulated increase in acidification rate could be potentiated by the 1,4‐benzodiazepine, flunitrazepam (100 nM). The 10 nM GABA response showed the maximal benzodiazepine facilitation (GABA alone, 1.4 μV s−1, GABA+flunitrazepam, 3.8 μV s−1, mean increment over basal, n=7).
The GABA‐stimulated increase in acidification rate was inhibited by the GABAA antagonist, bicuculline (100 μM) (90% inhibition at 1 mM GABA).
The results of this study show that activation of GABAA receptors in rat cerebellar granule cells caused an increase in the extracellular acidification rate; an effect which was potentiated by benzodiazepines and inhibited by a GABAA receptor antagonist. This paper defines the conditions and confirms the feasibility of using microphysiometry to investigate GABAA receptor function in primary cultured CNS neurones. The microphysiometer provides a rapid and sensitive technique to investigate the regulation of the GABAA receptor in populations of neurones.

British Journal of Pharmacology (1997) 121, 71–76; doi:10.1038/sj.bjp.0701106
Sharp Gaussian bounds and 𝐿^{𝑝}-growth of semigroups associated with elliptic and Schrödinger operators
Authors: Ouhabaz El Maati 
Published: August 2006

We prove sharp large time Gaussian estimates for heat kernels of elliptic and Schrödinger operators, including Schrödinger operators with magnetic fields. Our estimates are then used to prove that for general (magnetic) Schrödinger operators

A
=
−

∑

k
=
1

d

(

∂

∂

x
k

−
i

b
k

)
2

+
V

A=-\sum _{k = 1}^d (\tfrac {\partial }{\partial x_k}-i b_k)^2 + V

, we have the

L
∞

L^\infty

-estimate (for large

t
t

):
\[

‖

e

−
t
A

‖

L

(

L
∞

(

R

d

)
)

≤
C

e

−
s
(
A
)
t

(
t
ln
⁡
t

)

d

/

4

\Vert e^{-tA} \Vert _{{\mathcal L}(L^\infty (\mathbb {R}^d))} \le C e^{-s(A)t} ( t\ln t)^{d/4}

\]
where

s
(
A
)
:=
inf
σ
(
A
)

s(A) := \inf \sigma (A)

is the spectral bound of

A
.

A.

The same estimate holds for elliptic and Schrödinger operators on general domains.