bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of angiotensin II formation in human isolated bladder by selective inhibitors of ACE and human chymase: a functional and biochemical study
Authors: Waldec Kristian , Fredrik Lindberg B , Persson Katarina , Andersson Karl‐Erik
Published: August 2006

Functional recordings of smooth muscle tension and biochemical experiments on membrane fractions were performed to characterize angiotensin II (AII) formation in human isolated bladder smooth muscle.

A novel human chymase inhibitor CH 5450 (Z‐Ile‐Glu‐Pro‐Phe‐CO2Me) and a recently developed human chymase substrate Pro11‐,d‐Ala12)‐angiotensin I, claimed to be resistant to angiotensin converting enzyme (ACE) and carboxypeptidase, were used.

Angiotensin I (AI) (0.3μm) induced a contractile response amounting to 58±5% (n=12) of the initial K+ (124mm)‐induced contractions. This response was reduced to 36±3% (n=8) by the ACE‐inhibitor enalaprilat (10μm), while pretreatment with soybean trypsin inhibitor (STI 200μg ml−1) or CH 5450 (10μm) had no effect. However, the combination of enalaprilat and STI reduced the AI‐induced contractions to 19±5% (n=6), and the combination of enalaprilat and CH 5450 caused an almost complete inhibition of the AI‐induced contractions to 1±1% (n=6).

The substrate (Pro11‐,d‐Ala12)‐AI (3μm) produced contractions which amounted to 57±4% (n=13) of the initial K+ (124mm) contractions. These contractions were not affected by enalaprilat (10μm). On the other hand, STI (200μgml−1) and CH 5450 (10μm) added separately, depressed the (Pro11‐,d‐Ala12)‐AI‐induced contractions to 34±5% (n=6) and 24±4% (n=6), respectively. The combination of enalaprilat and STI or enalaprilat and CH 5450 did not produce any further inhibition.

Experiments with detrusor membrane fractions incubated with AI (50μm) were performed. In the presence of enalaprilat (100μm), carboxypeptidase inhibitor CPI (10μgml−1) and aprotinin (15μm), CH 5450 (10nm–1μm) caused a concentration‐dependent inhibition of AII formation.

The results confirm that AII is a potent contractile agent in the human isolated detrusor muscle. They also indicate that the serine protease responsible for AII formation in the human bladder in vitro is human chymase or an enzyme similar to human chymase.
Signalling pathways in bradykinin‐ and nitric oxide‐induced hypotension in the normotensive rat; role of K+‐channels
Authors: Berg Torill , Koteng Øyvind
Published: August 2006

Bradykinin and nitric oxide (NO) are potent hypotensive agents. In the present study, the role of K+‐channels in the signalling pathways responsible for their hypotensive action was investigated in normotensive, anaesthetized rats. The rats were treated with ion‐channel inhibitors before administration of bradykinin (2.8, 5.6, 28 and 56nmolkg−1, i.v.) followed in some of the protocols by nitroprusside (1.1, 3.5, 7, 14, and 28nmolkg−1, i.v.).

No attenuation of the hypotensive response to bradykinin was detected for inhibitors of the Na‐K‐Cl‐cotransporter (30μmolkg−1 furosemide), the ATP‐sensitive K+‐channel (40μmolkg−1 glibenclamide), high conductance Ca2+‐activated K+‐channel (180μmolkg−1 tetraethylammonium, 54μmolkg−1 tetrabutylammonium, 35nmolkg−1 iberiotoxin, 35nmolkg−1 charybdotoxin) or the low conductance Ca2+‐activated K+‐channel (74nmolkg−1 apamin).

However, the voltage‐sensitive K+‐channel (IA) inhibitor 4‐aminopyridine (4.05–40.5μmolkg−1) induced a concentration‐dependent (P<0.0001) attenuation of the hypotensive response (P<0.0001). Bradykinin had no effect on heart rate in anaesthetized rats and this observation was not altered by pretreatment with 4‐aminopyridine.

4‐Aminopyridine (53μmolkg−1) also significantly attenuated the hypotensive response to nitroprusside (P<0.0003) without altering the heart rate concentration‐response curve. Of the two Ca2+‐activated K+‐channel inhibitors tested on nitroprusside‐induced hypotension, tetrabutylammonium induced a slight attenuation (P<0.0101), whereas iberiotoxin had no effect.

We therefore concluded that, although the acute hypotensive response to bradykinin in the normotensive rat is not mediated through nitric oxide synthesis, the hypotensive response to both agents was mediated through opening of voltage‐sensitive K+‐channels (IA), resulting in a decrease in peripheral vascular resistance.
Predominant role of A1 adenosine receptors in mediating adenosine induced vasodilatation of rat diaphragmatic arterioles: involvement of nitric oxide and the ATP‐dependent K+ channels
Authors: Danialou Gawiyou , Vicaut Eric , Sambe Abdoulaye , Aubier Michel , Boczkowski Jorge
Published: August 2006

We investigated, by intravital microscopy in rats, the role of the subtypes of adenosine receptors A1 (A1/AR) and A2 (A2AR) in mediating adenosine‐induced vasodilatation of second and third order arterioles of the diaphragm.

Adenosine, and the A1AR selective agonists R(−)‐N6‐(2‐phenylisopropyl)‐adenosine (R‐PIA) and N6‐cyclo‐pentyl‐adenosine (CPA) induced a similar concentration‐dependent dilatation of diaphragmatic arterioles. The non selective A2AR subtype agonist N6‐[2‐(3,5‐dimethoxyphenyl)‐2‐(2‐methylphenyl) ethyl]adenosine (DPMA) also dilated diaphragmatic arterioles but induced a significantly smaller dilatation than adenosine. By contrast the selective A2aAR subtype agonist 2‐[p‐(2‐carboxyethyl)phenyl amino]‐5′‐N‐ethyl carboxamido adenosine (CGS 21680) did not modify diaphragmatic arteriolar diameter.

The non selective adenosine receptor antagonist 1,3‐dipropyl‐8‐p‐sulphophenylxanthine (SPX, 100 μM) and the selective A1AR antagonist 8‐cyclopentyl‐1,3‐dipropylxanthine (CPX, 50 nM) significantly attenuated adenosine‐induced dilatation of diaphragmatic arterioles. By contrast, adenosine significantly dilated diaphragmatic arterioles in the presence of A2AR antagonist 3,7‐dimethyl‐1‐propargylxanthine (DMPX, 10 μM).

The dilatation induced by adenosine was unchanged by the mast cell stabilizing agent sodium cromoglycate (cromolyn, 10 μM).

The nitric oxide (NO) synthase inhibitor Nω‐nitro‐L‐arginine (L‐NOARG, 300 μM) attenuated the dilatation induced by adenosine, and by the A1AR and A2AR agonists.

The ATP‐dependent K+ channel blocker glibenclamide (3 μM) significantly attenuated diaphragmatic arteriolar dilatation induced by adenosine and by the A1AR agonists R‐PIA and CPA. By contrast, glibenclamide did not significantly modify arteriolar dilatation induced by the A2AR agonist DPMA.

These findings suggest that adenosine‐induced dilatation of diaphragmatic arterioles in the rat is predominantly mediated by the A1AR, via the release of NO and activation of the ATP‐dependent K+ channels.
A comparative study of the effects of three guanylyl cyclase inhibitors on the L‐type Ca2+ and muscarinic K+ currents in frog cardiac myocytes
Authors: Abi‐Gerges Najah , Hove‐Madsen Leif , Fischmeister Rodolphe , Méry Pierre‐François
Published: August 2006

To investigate the participation of guanylyl cyclase in the muscarinic regulation of the cardiac L‐type calcium current (ICa), we examined the effects of three guanylyl cyclase inhibitors, 1H‐[1,2,4]oxidiazolo[4,3‐a]quinoxaline‐1‐one (ODQ), 6‐anilino‐5,8‐quinolinedione (LY 83583), and methylene blue (MBlue), on the β‐adrenoceptor; muscarinic receptor and nitric oxide (NO) regulation of ICa and on the muscarinic activated potassium current IK,ACh, in frog atrial and ventricular myocytes.

ODQ (10 μM) and LY 83583 (30 μM) antagonized the inhibitory effect of an NO‐donor (S‐nitroso‐N‐acetylpenicillamine, SNAP, 1 μM) on the isoprenaline (Iso)‐stimulated ICa which was consistent with their inhibitory action on guanylyl cyclase. However, MBlue (30 μM) had no effect under similar conditions.

In the absence of SNAP, LY 83583 (30 μM) potentiated the stimulations of ICa by either Iso (20 nM), forskolin (0.2 μM) or intracellular cyclic AMP (5–10 μM). ODQ (10 μM) had no effect under these conditions, while MBlue (30 μM) inhibited the Iso‐stimulated ICa.

LY 83583 and MBlue, but not ODQ, reduced the inhibitory effect of up to 10 μM acetylcholine (ACh) on ICa.

MBlue, but not LY 83583 and ODQ, antagonized the activation of IK,ACh by ACh in the presence of intracellular GTP, and this inhibition was weakened when IK,ACh was activated by intracellular GTPγS.

The potentiating effect of LY 83583 on Iso‐stimulated ICa was absent in the presence of either DL‐dithiothreitol (DTT, 100 μM) or a combination of superoxide dismutase (150 u ml−1) and catalase (100 u ml−1).

All together, our data demonstrate that, among the three compounds tested, only ODQ acts in a manner which is consistent with its inhibitory action on the NO‐sensitive guanylyl cyclase. The two other compounds produced severe side effects which may involve superoxide anion generation in the case of LY 83583 and alteration of β‐adrenoceptor and muscarinic receptor‐coupling mechanisms in the case of MBlue.
Effect of SB‐205384 on the decay of GABA‐activated chloride currents in granule cells cultured from rat cerebellum
Authors: Meadows H J , Harries M H , Thompson M , Benham C D
Published: August 2006

4‐Amino‐7‐hydroxy‐2‐methyl‐5,6,7,8,‐tetrahydrobenzo[b]thieno[2,3‐b]pyridine‐3‐carboxylic acid, but‐2‐ynyl ester (SB‐205384) and other γ‐aminobutyric acidA (GABAA) receptor modulators were tested for their effects on GABA‐activated chloride currents in rat cerebellar granule cells by use of the whole‐cell patch clamp technique.

The major effect of SB‐205384 on GABAA‐activated current was an increase in the half‐life of decay of the response once the agonist had been removed. This is in contrast to many GABAA receptor modulators that have previously been shown to potentiate GABA‐activated currents.

This profile could be explained if SB‐205384 stabilizes the channel in open and desensitized states so that channel closing is dramatically slowed. Such a modulatory profile may produce a novel behavioural profile in vivo.
Pharmacological characterization of the receptors involved in the β‐adrenoceptor‐mediated stimulation of the L‐type Ca2+ current in frog ventricular myocytes
Authors: Arvydas Skeberdis V , Jurevičius Jonas , Fischmeister Rodolphe
Published: August 2006

The whole‐cell patch‐clamp was used for studying the effects of various β1‐ and β2‐adrenoceptor agonists and antagonists on the L‐type Ca current (ICa) in frog ventricular myocytes.

Dose‐response curves for the effects of isoprenaline (non selective β‐agonist), salbutamol (β2‐agonist), dobutamine (β1‐agonist) on ICa were obtained in the absence and presence of various concentrations of ICI 118551 (β2‐antagonist), metoprolol (β1‐antagonist) and xamoterol (partial β1‐agonist) to derive EC50 (i.e. the concentration of β‐agonist at which the response was 50% of the maximum) and Emax (the maximal response) values by use of a Michaelis equation. Schild regression analysis was performed to examine whether the antagonists were competitive and to determine the equilibrium dissociation constant (KB) for the antagonist‐receptor complex.

Isoprenaline increased ICa with an EC50 of 20.0 nM and an Emax of 597%. ICI 118551 and metoprolol competitively antagonized the effect of isoprenaline with a KB of 3.80 nM and 207 nM, respectively.

Salbutamol increased ICa with an EC50 of 290 nM and an Emax of 512%. ICI 118551 and metoprolol competitively antagonized the effect of salbutamol with a KB of 1.77 nM and 456 nM, respectively.

Dobutamine increased ICa with an EC50 of 2.40 μM and an Emax of 265%. ICI 118551 and metoprolol competitively antagonized the effect of dobutamine with a KB of 2.84 nM and 609 nM, respectively.

Xamoterol had no stimulating effect on ICa. However, xamoterol competitively antagonized the stimulating effects of isoprenaline, salbutamol and dobutamine on ICa with a KB of 58–64 nM.

We conclude that a single population of receptors is involved in the β‐adrenoceptor‐mediated regulation of ICa in frog ventricular myocytes. The pharmacological pattern of the response of ICa to the different β‐adrenoceptor agonists and antagonists tested suggests that these receptors are of the β2‐subtype.
Increased function of inhibitory neuronal M2 muscarinic receptors in diabetic rat lungs
Authors: Belmonte Kristen E , Jacoby David B , Fryer Allison D
Published: August 2006

The function of inhibitory neuronal M2 muscarinic receptors in diabetic rat lungs was investigated.

Neuronal M2 muscarinic receptors inhibit acetylcholine release from parasympathetic nerves. Thus, stimulation of neuronal M2 muscarinic receptors with muscarinic agonists, such as pilocarpine, inhibits acetylcholine release and vagally induced bronchoconstriction. In contrast, blockade of neuronal M2 muscarinic receptors with selective M2 muscarinic antagonists, such as AF‐DX 116, potentiates acetylcholine release and vagally induced bronchoconstriction.

Rats were made diabetic by streptozotocin (65 mg kg−1, i.v.). After 7–14 days the rats were anaesthetized with urethane (1.5 g kg−1, i.p.), tracheostomized, vagotomized, ventilated and paralysed with suxamethonium (30 mg kg−1, i.v.). Some 7 day diabetic rats were treated with low doses of long acting (NPH) insulin (2 units day−1, s.c.) for 7 days before experimentation. This dose of insulin was not sufficient to restore normoglycaemia in diabetic rats. Thus, insulin‐treated diabetic rats remained hyperglycaemic.

Distal electrical stimulation (5–70 Hz, 6 s, 40 V, 0.4 ms) of the vagi caused bronchoconstriction, measured as an increase in inflation pressure and bradycardia. In diabetic rats, vagally induced bronchoconstriction was significantly depressed vs controls. In contrast, bronchoconstriction caused by i.v. acetylcholine was similar in diabetic and control animals.

The function of neuronal M2 muscarinic receptors was tested with the muscarinic agonist pilocarpine (0.001–100.0 μg kg−1, i.v.) and the antagonist AF‐DX 116 (0.01–3.0 mg kg−1, i.v.). Pilocarpine inhibited vagally‐induced bronchoconstriction (30 Hz, 20–40 V, 0.4 ms at 6 s) and AF‐DX 116 potentiated vagally‐induced bronchoconstriction (20 Hz, 20–40 V, 0.4 ms at 6 s) to a significantly greater degree in diabetic rats compared to controls.

Both frequency‐dependent vagally‐induced bronchoconstriction and M2 muscarinic receptor function could be restored to nearly control values in diabetic rats treated with low doses of insulin.

Displacement of [3H]QNB (1 nM) with the agonist carbachol (10.0 nM–10.0 mM) from diabetic cardiac M2 muscarinic receptors revealed a half log increase in agonist binding affinity at both the high and low affinity binding sites vs controls. In contrast, M2 receptors from insulin‐treated diabetic rat hearts showed no significant difference in binding affinity vs controls.

These data show that neuronal M2 muscarinic receptors in the lungs have increased function in diabetic rats, suggesting that insulin modulates M2 muscarinic receptor function.
Fluoroquinolone (ciprofloxacin) secretion by human intestinal epithelial (Caco‐2) cells
Authors: Cavet M. E. , West M , Simmons N. L.
Published: August 2006

Human intestinal epithelial Caco‐2 cells were used to investigate the mechanistic basis of transepithelial secretion of the fluoroquinolone antibiotic ciprofloxacin.

Net secretion and cellular uptake of ciprofloxacin (at 0.1 mM) were not subject to competitive inhibition by sulphate, thiosulphate, oxalate, succinate and para‐amino hippurate, probenecid (10 mM), taurocholate (100 μM) or bromosulphophthalein (100 μM). Similarly tetraethylammonium and N‐′methylnicotinamide (10 mM) were without effect.

Net secretion of ciprofloxacin was inhibited by the organic exchange inhibitor 4,4′‐diisothiocyanostilbene‐2‐2′‐disulphonic acid (DIDS, 400 μM).

Net secretion of ciprofloxacin was partially inhibited by 100 μM verapamil, whilst net secretion of the P‐glycoprotein substrate vinblastine was totally abolished under these conditions. Ciprofloxacin secretion was unaltered after preincubation of cells with two anti‐P‐glycoprotein antibodies (UIC2 and MRK16), which both significantly reduced secretory vinblastine flux (measured in the same cell batch). Ciprofloxacin (3 mM) failed to inhibit vinblastine net secretion in Caco‐2 epithelia, and was not itself secreted by the P‐glycoprotein expressing and vinblastine secreting dog kidney cell line, MDCK.

Net secretion and cellular uptake of ciprofloxacin (at 0.1 mM) were not subject to alterations of either cytosolic or medium pH, or dependent on the presence of medium Na+, Cl− or K+ in the bathing media.

The substrate specificity of the ciprofloxacin secretory transport in Caco‐2 epithelia is distinct from both the renal organic anion and cation transport. A role for P‐glycoprotein in ciprofloxacin secretion may also be excluded. A novel transport mechanism, sensitive to both DIDS and verapamil mediates secretion of ciprofloxacin by human intestinal Caco‐2 epithelia.

British Journal of Pharmacology (1997) 121, 1567–1578; doi:10.1038/sj.bjp.0701302
Induction of neutrophil chemotactic factor production by staurosporine in rat peritoneal neutrophils
Authors: Edamatsu Takeo , Xiao Yi‐Qun , Tanabe Jun‐ichi , Mue Suetsugu , Ohuchi Kazuo
Published: August 2006

Incubation of rat peritoneal neutrophils in medium containing various concentrations of staurosporine (6.4–64 nM) increased the neutrophil chemotactic activity in the conditioned medium in a time‐ and concentration‐dependent manner.

Separation of the neutrophil chemotactic activity in the conditioned medium by isoelectric focusing revealed that staurosporine (64 nM) stimulated the production of basic (pH>8) neutrophil chemotactic factors, while TPA (12‐O‐tetradecanoylphorbol 13‐acetate, 49 nM) stimulated the production of both basic (pH>8) and acidic (pH 5) neutrophil chemotactic factors.

Determination by immunoassay of cytokine‐induced neutrophil chemoattractant (CINC)‐1, ‐2α, ‐2β and ‐3 in the conditioned medium at 4 h revealed that staurosporine (64 nM) and TPA (49 nM) strongly stimulated the production of CINC‐3 (staurosporine, 133.0±3.8; TPA, 26.7±1.0; control, 0.32±0.01 ng ml−1, means±s.e.mean from four samples) compared to CINC‐1 (staurosporine, 55.0±1.2; TPA, 12.2±0.3; control, 0.56±0.01 ng ml−1), and CINC‐2α (staurosporine, 1.09±0.03; TPA, 0.90±0.02; control, <0.10 ng ml−1). CINC‐2β was below the detectable amount (<0.078 ng ml−1).

The level of CINC‐3 mRNA in the peritoneal neutrophils was determined by reverse transcription‐polymerase chain reaction. Staurosporine (64 nM) and TPA (49 nM) enhanced the level of CINC‐3 mRNA time‐dependently, but had no effect on GAPDH mRNA levels.

Production of staurosporine‐induced neutrophil chemotactic factor was inhibited by the protein kinase C inhibitors, H‐7 (IC50, 12.3 μM), calphostin C (IC50, 0.77 μM) and Ro 31‐8425 (24.3% inhibition at 10 μM), and by the tyrosine kinase inhibitor, genistein (IC50, 68.5 μM). Production of TPA‐induced neutrophil chemotactic factor was also inhibited by both inhibitors.

Both the staurosporine‐ and the TPA‐induced increase in CINC‐3 mRNA levels were suppressed by H‐7 and genistein.

British Journal of Pharmacology (1997) 121, 1651–1658; doi:10.1038/sj.bjp.0701322
Characterization of the binding of [3H]‐SB‐204269, a radiolabelled form of the new anticonvulsant SB‐204269, to a novel binding site in rat brain membranes
Authors: Herdon Hugh J. , Jerman Jeffrey C. , Stean Tania O. , Middlemiss Derek N. , Chan Wai N. , Vong Antonio K. , Evans John M. , Thompson Mervyn , Upton Neil
Published: August 2006

SB‐204269 (trans‐(+)‐6‐acetyl‐4S‐(4‐fluorobenzoylamino)‐3,4‐dihydro‐2,2‐dimethyl‐2H‐benzol[b]pyran‐3R‐ol, hemihydrate) shows potent anticonvulsant activity in a range of animal seizure models, with a lack of neurological or cardiovascular side‐effects. The profile of the compound suggests that it may have a novel mechanism of action. This study describes the characteristics of a binding site for [3H]‐SB‐204269 in rat forebrain membranes.

Specific [3H]‐SB‐204269 binding was saturable and analysis indicated binding to a homogenoeous population of non‐interacting binding sites with a dissociation constant (KD) of 32±1 nM and a maximum binding capacity (Bmax) of 253±18 fmol mg−1 protein. Kinetic studies indicated monophasic association and dissociation. Binding was similar in HEPES or Tris‐HCl buffers and was unaffected by Na+, K+, Ca2+ or Mg2+ ions. Specific binding was widely distributed in brain, but was minimal in a range of peripheral tissues.

Specific [3H]‐SB‐204269 binding was highly stereoselective, with a 1000 fold difference between the affinities of SB‐204269 and its enantiomer SB‐204268 for the binding site. The affinities of analogues of SB‐204269 for binding can be related to their activities in the mouse maximal electroshock seizure threshold (MEST) test of anticonvulsant action.

None of the standard anticonvulsant drugs, phenobarbitone, phenytoin, sodium valproate, carbamazepine, diazepam and ethosuximide, or the newer anticonvulsants, lamotrigine, vigabatrin, gabapentin and levetiracetam, showed any affinity for the [3H]‐SB‐204269 binding site. A wide range of drugs active at amino acid receptors, Na+ or K+ channels or various other receptors did not demonstrate any affinity for the binding site.

These studies indicate that SB‐204269 possesses a specific CNS binding site which may mediate its anticonvulsant activity. This binding site does not appear to be directly related to the sites of action of other known anticonvulsant agents, but may have an important role in regulating neuronal excitability.

British Journal of Pharmacology (1997) 121, 1687–1691; doi:10.1038/sj.bjp.0701331
The effect of saliva or serum on bacterial and Candida albicans colonization on type I collagen
Authors: NIKAWA H. , EGUSA H. , YAMASHIRO H. , NISHIMURA M. , MAKIHIRA S. , JIN C. , FUKUSHIMA H. , HAMADA T.
Published: August 2006

summary  Colonization of Candida albicans on oral surfaces can serve as a reservoir for disseminated infections, such as aspiration pneumonia and gastrointestinal infection, particularly in the immunocompromised host. Therefore, the aim of this study was to investigate the effects of salivary and serum pellicles on C. albicans, Streptococcus mutans, S. sanguis, Lactobacillus and Actinomyces colonization on type I collagen, a major organic component of periodontal ligaments. The colonization potential of two isolates each of C. albicans, S. mutans and S. sanguis, and a single isolate each of Lactobacillus and Actinomyces to uncoated (control), saliva‐coated or serum‐coated type I collagen plates (surface area 143 mm2, Cell Disk; Sumitomo, Tokyo, Japan) was examined using a bioluminescent adenosine triphosphate assay based on firefly luciferase–luciferin system. The results revealed that with mutans streptococci, a saliva pellicle was significantly more effective in promoting bacterial colonization compared with the pellicle‐free collagen disc, and the serum‐coated sample significantly inhibited the colonization of streptococci (anova; P < 0ḃ01). In contrast, in the case of C. albicans, Lactobacillus and Actinomyces isolates, a serum pellicle was significantly more effective in promoting the colonization, followed by saliva pellicle and uncoated specimen (anova; P < 0ḃ01). These results suggested that crevicular fluid rich in seruminous components would promote the colonization of Candida, Lactobacillus and Actinomyces on type I collagen as opposed to streptococci which showed greater avidity to saliva‐coated collagen.
Hospitality, Improvisation and Gestell: A Phenomenology of Mobile Information
Authors: Brigham Martin , Introna Lucas D.
Published: August 2006

This paper reports on longitudinal research into the implementation and use of the first mobile vehicle mounted data system (VMDS) at a UK fire service. Using insights from Claudio Ciborra's work, the paper develops a phenomenological ontology for conceptualising the co-constitutive relation between organisational practices and information technology mediated practices. The paper sets out how the brigade's mobile data system can be understood in terms hospitality, improvisation and Gestell. It is argued that despite the seemingly innocent and potentially mundane replacement of paper-based practices by electronically mediated mobile information and communication, the VMDS is associated with significant and far-reaching outcomes, both empirical and ontological, within the brigade and for the modernisation of fire service provision across the UK. We suggest that the dynamic of hospitality between guest and host provides a way to think through and beyond the deployment information infrastructures as enframed by a technological mood. The paper concludes with some general implications for a phenomenology of information technology.
Object Lessons and Invisible Technologies
Authors: Whitley Edgar A , Darking Mary
Published: August 2006

In this paper, we explore some of Claudio Ciborra's ideas about the technological object. We do this in contrast to recent analysis by Law and Singleton (L&S) that advocates a methodological radicalism that moves beyond epistemological uncertainties about the technological object to ontological concerns. L&S present a series of stages in this analysis that include fluid objects that change relatively gently and fire objects that have more radical discontinuities. This approach is applied to empirical work studying the engagement practices of a large, sophisticated information infrastructure research project, the Digital Business Ecosystem (DBE). At the start of the DBE engagement process, the DBE was an invisible technology that did not exist and this made the process of engagement with it particularly challenging. Drawing on the analysis presented by, however, the DBE appears to have the ontological characteristics of both the fluid and the fire object. In order to address this dilemma, we draw upon Ciborra's thinking, particularly around the information infrastructure and Gestell as a means that allows us to consider technologies like the DBE as being both fluid and fire objects. The paper ends with a discussion of the implications of this work on Claudio Ciborra's legacy for the study of information and communications technologies.
Sowing the Seeds of is Cultivation in Public Service Organisations
Authors: De Marco Marco , Sorrentino Maddalena
Published: August 2006

This paper aims to highlight the relevance of a cultivation approach with the goal of exploring the concrete implications it may have for public administrations (PA) involved in projects of organisational change. We suggest that adopting an approach to change that reflects the cultivation perspective is an unavoidable choice for PA, much more so than it is for the corporate world. The claim is that public-sector organisations design and implement organisational solutions that find it hard to move away from the ‘maintenance’ logic of legacy systems. Compared with the rational perspective, which is geared entirely to establishing optimal relations between means and ends, the cultivation approach enables us to make valuable advances at the interpretive level. We argue that the value of the processual and incremental perspective can be useful in creating a more realistic and less illusory reconstruction of the relationship between technological change and organisational change. In this paper, we discuss how combining policy studies with ICT social studies can help empower the cultivation logic, originating new tools for analysing and evaluating e-government results.
Thin layer quantization in higher dimensions and codimensions
Authors: Golovnev Alexey V.
Published: August 2006

We consider the thin layer quantization with use of only the most elementary notions of differential geometry. We consider this method in higher dimensions and get an explicit formula for quantum potential. For codimension 1 surfaces the quantum potential is presented in terms of principal curvatures, and equivalence with Prokhorov quantization method is proved. It is shown that, in contrast with original da Costa method, Prokhorov quantization can be generalized directly to higher codimensions.
Thermodynamic properties of van der Waals fluids from Monte Carlo simulations and perturbative Monte Carlo theory
Authors: Díez A. , Largo J. , Solana J. R.
Published: August 2006

Computer simulations have been performed for fluids with van der Waals potential, that is, hard spheres with attractive inverse power tails, to determine the equation of state and the excess energy. On the other hand, the first- and second-order perturbative contributions to the energy and the zero- and first-order perturbative contributions to the compressibility factor have been determined too from Monte Carlo simulations performed on the reference hard-sphere system. The aim was to test the reliability of this “exact” perturbation theory. It has been found that the results obtained from the Monte Carlo perturbation theory for these two thermodynamic properties agree well with the direct Monte Carlo simulations. Moreover, it has been found that results from the Barker-Henderson [J. Chem. Phys. 47, 2856 (1967)] perturbation theory are in good agreement with those from the exact perturbation theory.
Implosion dynamics and radiative characteristics of a high yield structured gas puff load
Authors: Levine J. S. , Banister J. W. , Failor B. H. , Qi N. , Sze H. M. , Velikovich A. L. , Commisso R. J. , Davis J. , Lojewski D.
Published: August 2006

A large diameter gas puff nozzle, designed to produce a radial mass profile with a substantial fraction of the injected mass on the axis, has demonstrated an increase in K shell yield by nearly a factor of 2, to 21kJ, in an argon Z pinch at 3.5MA peak current and 205ns implosion time [H. Sze, J. Banister, B. H. Failor, J. S. Levine, N. Qi, A. L. Velikovich, J. Davis, D. Lojewski, and P. Sincerny, Phys. Rev. Lett. 95, 105001 (2005)] and 80kJ at 6MA and 227ns implosion time. The initial gas distribution produced by this nozzle has been determined and related to measured plasma dynamics during the implosion run-in phase. The role of two gas shells and the center jet are elucidated by the inclusion of a tracer element sequentially into each of the three independent plenums and by evacuating each plenum. The implosion dynamics and radiative characteristics of the Z pinches are presented.
A Brownian dynamics-finite element method for simulating DNA electrophoresis in nonhomogeneous electric fields
Authors: Kim Ju Min , Doyle Patrick S.
Published: August 2006

The objective of this work is to develop a numerical method to simulate DNA electrophoresis in complicated geometries. The proposed numerical scheme is composed of three parts: (1) a bead-spring Brownian dynamics (BD) simulation, (2) an iterative solver-enhanced finite element method (FEM) for the electric field, and (3) the connection algorithm between FEM and BD. A target-induced searching algorithm is developed to quickly address the electric field in the complex geometry which is discretized into unstructured finite element meshes. We also develop a method to use the hard-sphere interaction algorithm proposed by Heyes and Melrose [J. Non-Newtonian Fluid Mech. 46, 1 (1993)] in FEM. To verify the accuracy of our numerical schemes, our method is applied to the problem of λ-DNA deformation around an isolated cylindrical obstacle for which the analytical solution of the electric field is available and experimental data exist. We compare our schemes with an analytical approach and there is a good agreement between the two. We expect that the present numerical method will be useful for the design of future microfluidic devices to stretch and∕or separate DNA.
Influence of surface chemical heterogeneities on adsorption/desorption hysteresis and coexistence diagram of metastable states within cylindrical pores
Authors: Puibasset Joël
Published: August 2006

Grand canonical Monte Carlo simulations are performed to determine the adsorption/desorption isotherms at different temperatures of a Lennard-Jones fluid confined within a simple model of cylindrical pores presenting chemical heterogeneities. A complex hysteresis loop is observed, showing hysteresis subloops (scanning curves). This is shown to be consistent with the existence of several metastable states (local minima in the system free energy). A recent extension to the Gibbs ensemble technique is then used to calculate the complete coexistence diagram of these local minima.
Liouville theory and uniformization of four-punctured sphere
Authors: Hadasz Leszek , Jaskólski Zbigniew
Published: August 2006

A few years ago Zamolodchikov and Zamolodchikov proposed an expression for the four-point classical Liouville action in terms of the three-point actions and the classical conformal block [Nucl. Phys. B 477, 577 (1996)]. In this paper we develop a method of calculating the uniformizing map and the uniformizing group from the classical Liouville action on n-punctured sphere and discuss the consequences of Zamolodchikovs conjecture for an explicit construction of the uniformizing map and the uniformizing group for the sphere with four punctures.
Structure of stagnated plasma in aluminum wire array Z pinches
Authors: Hall G. N. , Pikuz S. A. , Shelkovenko T. A. , Bland S. N. , Lebedev S. V. , Ampleford D. J. , Palmer J. B. A. , Bott S. C. , Rapley J. , Chittenden J. P. , Apruzese J. P.
Published: August 2006

Experiments with aluminum wire array Z pinches have been carried out on the mega-ampere generator for plasma implosion experiments (MAGPIE) at Imperial College London [I. H. Mitchell et al., Rev. Sci. Instrum. 67, 1533 (1996)]. It has been shown that in these arrays, there are two intense sources of radiation during stagnation; Al XII line emission from a precursor-sized object, and both continuum and Al XIII radiation from bright spots of either significantly higher temperature or density randomly distributed around this object so as to produce a hollow emission profile. Spatially resolved spectra produced by spherically bent crystals were recorded, both time-integrated and time-resolved, and were used to show that these two sources of radiation peak at the same time.
The dust acoustic solitary waves in dusty plasmas: Effects of ultraviolet irradiation
Authors: Ren Li-Wen , Wang Zheng-Xiong , Wang Xiaogang , Liu Jin-Yuan , Liu Yue
Published: August 2006

The effects of ultraviolet irradiation on small but finite amplitude dust-acoustic solitons, are studied by the reductive perturbation method. The self-consistent dust charge variation is taken into account. It is shown that the ultraviolet irradiation can significantly lower the magnitude of the dust negative charge, and even make the dust grains charged positively. With the growth of the dust charge, the phase velocity and the width of the solitary wave increase, whereas its amplitude decreases. The related physical mechanism is discussed.
Dual-basis second-order Møller-Plesset perturbation theory: A reduced-cost reference for correlation calculations
Authors: Steele Ryan P. , DiStasio Robert A. , Shao Yihan , Kong Jing , Head-Gordon Martin
Published: August 2006

The resolution-of-the-identity (RI) approximation has placed the onus of the cost of a second-order Møller-Plesset (MP2) calculation on the underlying self-consistent field (SCF) calculation for many moderately sized molecules. A dual-basis approach to the SCF calculation, based on previous methods demonstrated for density functional theory, is combined with RI-MP2 calculations, and small basis subsets for cc-pVTZ, cc-pVQZ, and 6-311++G(3df,3pd) are presented. These subsets provide time savings of greater than 90%, with negligible errors in absolute and relative energies, compared to the associated full-basis counterpart. The method is tested with a series of rotational barriers, relative conformational energies of alanine tetrapeptides, as well as the full G3/99 molecular set. RI-MP2 calculations on alanine octapeptides (40 heavy atoms, 3460 basis functions), using cc-pVQZ, are presented. Results improve upon previous methods that diagonalize the virtual space separately.
Fourier transform infrared isotopic study of linear CrC3: Identification of the ν1(σ) mode
Authors: Bates S. A. , Rittby C. M. L. , Graham W. R. M.
Published: August 2006

A vibrational fundamental of linear CrC3 has been detected in the products from the laser ablation of chromium and carbon rods trapped in solid Ar at ∼10K. Fourier transform infrared measurements of frequencies and C13 isotopic shifts are in very good agreement with the predictions of density functional theory calculations at the B3LYP∕6-311G+(3df) level, resulting in the identification of the ν1(σ) stretching mode at 1789.5cm−1. This is the first optical detection of the linear isomer of the transition-metal carbide CrC3 for which previous photoelectron spectroscopic studies have reported evidence of both linear and cyclic isomers.
Equilibrium and dynamics of Langmuir monolayers when the interface is a selective solvent: Polystyrene-b-poly(t-butyl acrylate) block copolymers
Authors: Hilles Hani M. , Sferrazza Michele , Monroy Francisco , Ortega Francisco , Rubio Ramón G.
Published: August 2006

The surface pressure of monolayers of insoluble diblock copolymers has been measured. One of the blocks is made of poly(t-butyl acrylate) (PtBA), and the other one by polystyrene (PS). The interface is a good solvent for PtBA, while it is a poor solvent for PS. For the sake of comparison, monolayers of a PtBA homopolymer (good solvent conditions) and of poly(4-hydroxy styrene) (P4HS) (poor solvent conditions) have been also measured. It has been found that the relative length of the blocks plays an important role on the shape of the surface pressure Π versus surface concentration Γ curves and also on the shape of the equilibrium compressibility versus Γ curves. However, it does not affect the maximum value of Π reached at high Γ’s. Surprisingly, the ellipsometric thickness of the copolymer monolayers is almost independent of the relative length of the blocks. The dynamics of the monolayers has been studied by step compression and by surface-light scattering techniques. When Mw,PtBA⪢Mw,PS single exponential relaxations are observed. However, stretched exponentials are obtained for Mw,PS⩾Mw,PtBA. The relaxation times decrease with increasing Γ for all the copolymers studied. This is the behavior usually found for poor solvent conditions (P4HS) and opposite to that found for homopolymers under good solvent conditions [PtBA, poly(vinylacetate)]. This means that the solvent quality of the interface does not determine the pressure dependence of τ. The elasticity modulus of the monolayers in the kilohertz range takes values that are similar to those of the high-frequency limit of the relaxation experiments. This means that the relaxation processes have characteristic frequencies below 1Hz.
Magnetic sensor for the noncontact measurement of flexural vibrations of a nonferromagnetic metallic hollow cylinder
Authors: Han Soon Woo , Kim Yoon Young
Published: August 2006

A solenoid-type magnetic sensor is developed for noncontact measurement of flexural vibrations of a nonferromagnetic metallic cylinder. The sensor measures the vibration by means of the reversed Lorentz force mechanism but flexural vibrations are measured only when antisymmetrically polarized static bias magnetic field is applied to the cylinder. In this respect, the effect of the bias magnetic field distribution on vibration sensing was investigated in the first place. Because the sensor uses a solenoid, it can measure vibrations of a cylinder even if it is covered with insulation; no insulation removal is needed with this sensor. Fundamental experiments underlying the sensor characteristics were conducted and the developed sensor was applied for experimental modal testing of pipes with and without insulation.
Semi-analytical model for flux-pileup-limited, dynamically reconnecting systems in resistive magnetohydrodynamics
Authors: Simakov Andrei N. , Chacón Luis , Knoll Dana A.
Published: August 2006

A simple zero-dimensional model is proposed that synthesizes the complex dynamics of driven, two-dimensional, magnetically reconnecting systems within the resistive magnetohydrodynamics (MHD) framework. The model applies to the so-called asymptotic regime of the well-known magnetic island coalescence problem, where well-separated macroscopic “ideal” and microscopic “resistive” regions are assumed to exist. The dynamics of the ideal region is described in terms of the Lorentz and pressure gradient forces on current filaments, and conservation of magnetic flux; that of the resistive region is described in terms of plasma flow and magnetic field magnitudes at the current sheet boundaries. Matching of the two regions provides the evolution equation for the current sheet thickness. The results for the O-point position versus time, reconnection rate, current sheet thickness, etc., at different resistivities obtained from the model agree well with those from the fully nonlinear two-dimensional reduced MHD simulation.
On the formation of rings-on-a-string conformations in a single polyelectrolyte chain: A possible scenario
Authors: Sakaue Takahiro , Yoshikawa Kenichi
Published: August 2006

Recent single-molecular observations have revealed that a single giant DNA molecule assumes (micro) phase separated structures upon the addition of condensing agents. Electron and atomic force microscopy have clearly shown the coexistence of ordered tori and disordered coil structures within a single DNA molecule. Motivated by these experimental findings, we theoretically investigated the collapse transition of a single polyelectrolyte chain driven by the addition of condensing guest molecules. We found that the transition behavior critically depends on the degree of the surviving charge inside the torus. When the torus is charged, even slightly, “rings-on-a-string” structures are expected for a sufficiently long chain, owing to the combinational entropy of segment state distribution along the chain and the unique property of the stability of charged torus.
Application of Wigner and Husimi intracule based electron correlation models to excited states
Authors: Besley Nicholas A.
Published: August 2006

A new approach to the electron correlation problem based on phase space intracules derived from the Wigner distribution is applied to excited states. The computed electron correlation energy reduces the mean absolute error in the prediction of the excitation energies of 55 atomic excited states from 0.65eV for unrestricted Hartree-Fock to 0.32eV. This compares favorably to a mean absolute deviation of 0.52eV for second order Møller-Plesset perturbation theory and 0.35eV for the Lee-Yang-Parr functional. An analogous correlation model based on the Husimi distribution is developed. Predicted correlation energies and excitation energies from this model are significantly worse than for the Wigner intracule based model. Alternative correlation kernels may be more suitable for the Husimi intracule based approach.
Existence of weak solutions and trajectory attractors for the moist atmospheric equations in geophysics
Authors: Guo Boling , Huang Daiwen
Published: August 2006

In this paper, we consider the initial boundary value problem for the primitive equations of moist atmospheric dynamics that are used to describe the turbulent behavior of long-term weather prediction and climate changes. By the Faedo-Galerkin method, we obtain the existence of global weak solutions to the problem in a large-scale atmosphere. By studying the long-time behavior of solutions, we obtain trajectory and global attractors for the primitive equations of moist atmosphere.
Nanoscale surface self-patterning of FeAl single crystals by vacancy absorption process
Authors: Yoshimi K. , Tsunekane M. , Nakamura R. , Yamauchi A. , Hanada S.
Published: August 2006

The surface morphology of B2-structured FeAl single crystals is modified on a nanoscale by the absorption process of supersaturated thermal vacancies. A high density of nano to mesoscale surface pores is successfully produced by the vacancy absorption process through water quenching, surface treatments, and aging heat treatment. Their shape, size, and density can be controlled by varying the surface orientation of single crystals, quenching temperature, aging temperature, and aging time. These results suggest that surface self-patterning by the vacancy absorption process is a useful bottom-up technique for obtaining nanoscale surface patterns in metallic materials.
Comment on “Dynamics of water in a molecular sieve by quasielastic neutron scattering” [J. Chem. Phys. 122, 084505 (2005)]
Authors: Dyer A.
Published: August 2006

The molecular sieve zeolite studied in this publication has been incorrectly identified. This means that parts of the discussions and conclusions are open to question. The authors have assumed that the molecular structure of the zeolite is composed of discrete 10Å diameter pores, whereas it is actually one composed of cavities linked to create a three dimensional array in which the maximum cavity entrance is 7.4Å.
Reply to “Comment on ‘Dynamics of water in a molecular sieve by quasielastic neutron scattering’ ” [J. Chem. Phys. 125, 077101 (2006)]
Authors: Swenson J. , Jansson H. , Howells W. S. , Longeville S.
Published: August 2006

In the foregoing Comment by Dyer [J. Chem. Phys.125, 077101 (2006)], it is claimed that the structure of our molecular sieve is identical to that of faujasite. However, this is not the case for the commercially produced molecular sieve 13X, as we used in our study. Therefore, we still have no reason to believe that we have provided incorrect information regarding the structure of the sample we used in our study.
Evaluation of quantum correlation functions from classical data: Anharmonic models
Authors: Kim Hyojoon , Rossky Peter J.
Published: August 2006

The previously introduced method of evaluating quantum mechanical time correlation functions using as input only classical simulation data is generalized and applied to two anharmonic model systems, as a further test. The quantum correction approach utilizes the relation between a general quantum correlation function and its classical analog. For the tested models, we obtain numerical results of nonlinear correlation functions with comparable accuracy to that of the centroid molecular dynamics method, although the present method is much simpler to implement and not limited to real valued quantum correlation functions.
Intramolecular and intermolecular energy transfers in donor-acceptor linear porphyrin arrays
Authors: Rhee Hanju , Joo Taiha , Aratani Naoki , Osuka Atsuhiro , Cho Sung , Kim Dongho
Published: August 2006

We present highly time-resolved spontaneous fluorescence spectra of a porphyrin array system that consists of an energy donor and an acceptor linked by a phenyl group. The donors are meso-meso directly linked zinc(II) porphyrin arrays and the acceptor is a zinc(II) 5,15-di(phenylethynyl)porphyrin. The spectra over the entire Q (S1) emission band following the excitation of the donor B (S2) state have been measured directly without the conventional spectral reconstruction method. The time-resolved fluorescence spectra revealed detailed energy relaxation processes within the donor and subsequent energy transfer to the acceptor. The observed energy transfer rates to the acceptor are consistent with the Förster energy transfer rates calculated on the assumption that the energy is localized in the Q state of each porphyrin unit of the donor prior to the energy transfer. The passage of the energy deposited initially on one porphyrin unit of the donor to the acceptor illustrates a sequence of energy delocalization and localization processes before it finally reaches the acceptor.
Swept laser source at 1μm for Fourier domain optical coherence tomography
Authors: Zhang Jun , Wang Qiang , Rao Bin , Chen Zhongping , Hsu Kevin
Published: August 2006

A frequency swept source at 1μm wavelength for Fourier domain optical coherence tomography (FDOCT) was demonstrated. The source incorporates a fiber-coupled semiconductor optical amplifier gain module, a fiber Fabry-Pérot tunable filter, and fiber isolators to form a ring laser. The laser is capable of a scanning range of 64nm, 3dB sweep range of 31nm, and coherence length of 9.8mm at 2kHz sweep rate. Based on the swept source, a FDOCT system was developed which can achieve 12μm axial resolution in tissue. Imaging of pig retina was demonstrated with the FDOCT system.