bluuebunny/crossref_metadata_2025 huggingface dataset:
Stealing abandoned goods: possessory title in proceedings for theft
Authors: Hickey Robin
Published: September 2006

Where it is accepted in proceedings for theft that ownership of the goods allegedly stolen had been abandoned at the time they were taken, criminal courts must make determinations about the possibility of any other prior title to those goods. If a conviction for theft of abandoned goods is to be safe, the court must find a proprietary right or interest in some person other than the relinquishing owner or the defendant. This paper reviews the criminal and civil law authorities on the problem of lost or abandoned goods, and argues for a uniform approach to resolving such questions of title using the ordinary common law rules of possession.
Conscience, discretion and the creation of property rights
Authors: Hopkins Nicholas
Published: September 2006

This paper considers the utility of the concept of conscience or unconscionable conduct as a contemporary rationale for intervention in two principles applied where a person seeks to renege on an informal agreement relating to land: the principle in Rochefoucauld v Boustead; and transfers ‘subject to’ rights in favour of a claimant. By analysing the concept in light of our current understanding of the nature of judicial discretion and the use of general principles, it responds to arguments that unconscionability is too general a concept on which to base intervention. In doing so, it considers the nature of the discretion that is actually in issue when the court intervenes through conscience in these principles. However, the paper questions the use of constructive trusts as a response to unconscionability. It argues that there is a need, in limited circumstances, to separate the finding of unconscionability from the imposition of a constructive trust. In these limited circumstances, once unconscionability is found, the courts should have a discretion as to the remedy, modelled on that developed in the context of proprietary estoppel. The message underlying this paper is that many of the concerns expressed about unconscionability that have led to suggestions of alternative rationales for intervention can in fact be addressed whilst retaining an unconscionability analysis. Unconscionability remains a preferable rationale for intervention as it provides a common thread that links apparently separate principles and can assist our understanding of their scope.
Atrophy and hypertrophy of skeletal muscles: structural and functional aspects
Authors: Boonyarom O. , Inui K.
Published: September 2006

This review summarizes current information on structural and functional changes that occur during muscle atrophy and hypertrophy. Most published studies consider an increase in total mass of a muscle as hypertrophy, whereas a decrease in total mass of a muscle is referred to as atrophy. In hypertrophy, the rate of synthesis is much higher than the rate of degradation of muscle contractile proteins, leading to an increase in the size or volume of an organ due to enlargement of existing cells. When a muscle remains in disuse for a long period, the rate of degradation of contractile proteins becomes greater than the rate of replacement, resulting in muscle atrophy. This defect may occur as a result of lack of nutrition, loss of nerve supply, micro‐gravity, ageing, systemic disease, prolonged immobilization or disuse. An understanding of the specific modifications that occur during muscle atrophy and hypertrophy may facilitate the development of novel techniques, as well as new therapies for affected muscles.
Adventitia‐dependent mechanical properties of brachiocephalic ovine arteries in in vivo and in vitro studies
Authors: Cabrera Fischer E. I. , Bia D. , Camus J. M. , Zócalo Y. , De Forteza E. , Armentano R. L.
Published: September 2006

Aim:  An adventitia dependent regulation of the vascular smooth muscle tone has been described. However, if the adventitia plays an active role on arterial wall biomechanical behaviour and functions remains to be established. Our aim was to characterize the influence of adventitia on arterial wall mechanical properties and the arterial conduit and buffer functions.

Methods:  Ovine brachiocephalic arteries were studied in vivo (n = 8) and in vitro (with null tone) in a circulation mock (n = 8). Isobaric, isoflow and isofrequency studies were performed. In each segment, pressure and diameter waves were assessed before and after adventitia removal. From the arterial stress–strain relationship, we derived the elastic and the viscous modulus. The buffering and conduit functions were calculated using the Kelvin–Voigt's time constant and the inverse of the characteristic impedance, respectively.

Results:  In in vivo studies arterial diameter decreased after adventitia removal (P < 0.05). Elastic and viscous modulus in in vivo studies were significantly higher in adventitia‐removed arteries, compared with values in intact vessels (P < 0.05). This behaviour was not observed in in vitro experiments. An impairment of buffer and conduit functions was observed in vivo after adventitia removal (P < 0.05), while both functions remain unchanged in in vitro studies (P > 0.05).

Conclusions:  Arterial wall viscosity and elasticity were influenced by adventitia removal in in vivo studies, possibly by a smooth muscle‐dependent mechanism, since it was not present in in vitro experiments. Adventitia would be involved in a physiological mechanism of arterial wall viscous and elastic properties regulation, that could influence arterial buffering and conduit functions.
Prostaglandin E2release in gastric antral mucosa of guinea‐pigs: basal PGE2release by cyclo‐oxygenase 2 and ACh‐stimulated PGE2release by cyclo‐oxygenase 1
Authors: Shimamoto Chikao , Nakanishi Yoshihiko , Katsu Ken‐ichi , Nakano Takashi , Kubota Takahiro , Mori Hiroshi , Nakahari Takashi
Published: September 2006

Prostaglandin E2(PGE2), which is generated by two isoforms of cyclo‐oxygenase (COX1and COX2), is a key mediator in gastric mucosal defense. In the present study, antral mucosa of guinea‐pigs was incubated with various agonists or antagonists in a medium, the PGE2concentration of which was measured using a PGE2EIA kit. Prostaglandin E2was released from the antral mucosa spontaneously (basal PGE2release) and acetylcholine (ACh, 10 μm) enhanced the PGE2release (ACh‐stimulated PGE2release) was mediated via intracellular Ca2+concentration ([Ca2+]i). Arachidonic acid enhanced both forms of PGE2release, and a phospholipase A2inhibitor (amylcinnamoyl anthranilic acid) and COX inhibitors (acetylsalicylic acid and indomethacin) decreased them. 5‐(4‐Chlorophenyl)‐1‐(4‐methoxyphenyl)‐3‐trifluoromethylpyrazol (SC560, 100 nm, a COX1‐selective inhibitor) inhibited ACh‐stimulated PGE2release without any decrease in basal PGE2release.N‐(2‐Cyclohexyloxy‐4‐nitrophenyl) methanesulphonamide (NS398, 20 μm, a COX2‐selective inhibitor) decreased basal PGE2release without any reduction of ACh‐stimulated PGE2release. However, ionomycin (a Ca2+ionophore) increased PGE2release from antral mucosa in the presence of SC560 or NS398, suggesting that COX1and COX2are regulated by [Ca2+]i. These findings indicate that COX1‐containing cells have ACh receptors but COX2‐containing cells do not. Moreover, in isolated antral epithelial cells, SC560 decreased basal and ACh‐stimulated PGE2release, but NS398 did not. In conclusion, in antral mucosa, basal PGE2release is mainly maintained by COX2of non‐epithelial cells, and ACh‐stimulated PGE2release is maintained by COX1of epithelial cells.
The changing AMPK expression profile in differentiating mouse skeletal muscle myoblast cells helps confer increasing resistance to apoptosis
Authors: Niesler Carola U. , Myburgh Katherine H. , Moore Frances
Published: September 2006

AMP‐activated protein kinase (AMPK) functions as a α/β/γ heterotrimer to preserve ATP levels and so cell viability during stressful conditions. However, its role in aiding survival of adult skeletal muscle precursor cells is unclear. Using the differentiating mouse C2C12 postnatal skeletal muscle myoblast cell line, we have determined that proteins for the AMPK subunit isoforms α2 and γ2 are constitutively expressed, while those for α1, β1 and β2 are undetectable in undifferentiated myoblasts but increasingly expressed with differentiation to myotubes. Although the γ3 subunit is expressed at a low level in myoblasts, it too is expressed increasingly with differentiation to myotubes. The p50 but not the p72 isoform of the embryonic α subunit homologue MELK is expressed only in proliferating myoblasts, while the ARK5 α subunit homologue is increasingly expressed with differentiation. Myotubes displayed higher basal and stimulated α1/α2 AMPK activation than myoblasts. Furthermore, serum starvation resulted in less apoptosis of differentiated myotubes than of undifferentiated myoblasts. This reflects, in part, the increased expression of functional AMPK in the myotubes, since specific inhibition of AMPK activity with 6‐[4‐(2‐piperidin‐1‐ylethoxy)‐phenyl]‐3‐pyridin‐4‐ylpyrazolo[1,5‐α] pyrimidine (Compound C) exacerbated the apoptosis resulting from serum withdrawal. If these in vitro events can also occur in vivo, they could have implications for pathologies such as muscle wasting, in which undifferentiated satellite stem cells may be easier apoptotic targets than their differentiated counterparts. Furthermore, these results suggest that when interpreting results from in vitro or in vivo experiments on AMPK, the subunit expression profile should be taken into account.
Frequency‐dependent selection of reflexes by pudendal afferents in the cat
Authors: Boggs Joseph W. , Wenzel Brian J. , Gustafson Kenneth J. , Grill Warren M.
Published: September 2006

Activation of urethral or genital afferents of the pudendal nerve can elicit or inhibit micturition, and low frequency stimulation of the compound pudendal nerve (PN) is known to produce a continence response. The present study demonstrates that PN stimulation also can elicit a micturition‐like response and that the response to PN stimulation is dependent on stimulation frequency. We measured the changes in bladder pressure and external urethral sphincter (EUS) electroneurogram (ENG) evoked by PN stimulation before and up to 16 h after spinal cord transection (SCT) in cats anaesthetized with α‐chloralose. Low frequency (10 Hz) stimulation elicited a continence‐like response, including inhibition of the bladder and activation of the EUS, but mid‐frequency (33 Hz) stimulation produced a micturition‐like response, including excitation of the bladder without activation of the EUS. The dependence of the response on stimulus frequency was linked to interpulse interval as the same number of pulses at 10, 33 and 100 Hz produced different responses. Stimulation of the PN at 33 Hz produced bladder contractions before and 8 h after SCT provided the bladder contained a minimum volume of fluid. Only mid‐range frequency stimulation with sufficient stimulus train duration produced a reduction in EUS ENG activity before and after SCT. In addition to a continence‐like response, PN stimulation can also elicit a micturition‐like response, and this response is dependent on stimulation frequency, stimulus train duration, and bladder volume. The ability to control the two principal functions of the bladder by pudendal nerve stimulation is an exciting prospect for neurorehabilitation.
Evidence that GABA ρ subunits contribute to functional ionotropic GABA receptors in mouse cerebellar Purkinje cells
Authors: Harvey Victoria L. , Duguid Ian C. , Krasel Cornelius , Stephens Gary J.
Published: September 2006

Ionotropic γ‐amino butyric acid (GABA) receptors composed of heterogeneous molecular subunits are major mediators of inhibitory responses in the adult CNS. Here, we describe a novel ionotropic GABA receptor in mouse cerebellar Purkinje cells (PCs) using agents reported to have increased affinity for ρ subunit‐containing GABAC over other GABA receptors. Exogenous application of the GABAC‐preferring agonist cis‐4‐aminocrotonic acid (CACA) evoked whole‐cell currents in PCs, whilst equimolar concentrations of GABA evoked larger currents. CACA‐evoked currents had a greater sensitivity to the selective GABAC antagonist (1,2,5,6‐tetrahydropyridin‐4‐yl)methylphosphinic acid (TPMPA) than GABA‐evoked currents. Focal application of agonists produced a differential response profile; CACA‐evoked currents displayed a much more pronounced attenuation with increasing distance from the PC soma, displayed a slower time‐to‐peak and exhibited less desensitization than GABA‐evoked currents. However, CACA‐evoked currents were also completely blocked by bicuculline, a selective agent for GABAA receptors. Thus, we describe a population of ionotropic GABA receptors with a mixed GABAA/GABAC pharmacology. TPMPA reduced inhibitory synaptic transmission at interneurone–Purkinje cell (IN–PC) synapses, causing clear reductions in miniature inhibitory postsynaptic current (mIPSC) amplitude and frequency. Combined application of NO‐711 (a selective GABA transporter subtype 1 (GAT‐1) antagonist) and SNAP‐5114 (a GAT‐(2)/3/4 antagonist) induced a tonic GABA conductance in PCs; however, TPMPA had no effect on this current. Immunohistochemical studies suggest that ρ subunits are expressed predominantly in PC soma and proximal dendritic compartments with a lower level of expression in more distal dendrites; this selective immunoreactivity contrasted with a more uniform distribution of GABAAα1 subunits in PCs. Finally, co‐immunoprecipitation studies suggest that ρ subunits can form complexes with GABAA receptor α1 subunits in the cerebellar cortex. Overall, these data suggest that ρ subunits contribute to functional ionotropic receptors that mediate a component of phasic inhibitory GABAergic transmission at IN–PC synapses in the cerebellum.
In vivo ATP production during free‐flow and ischaemic muscle contractions in humans
Authors: Lanza Ian R. , Wigmore Danielle M. , Befroy Douglas E. , Kent‐Braun Jane A.
Published: September 2006

The aim of this study was to determine how ATP synthesis and contractility in vivo are altered by ischaemia in working human skeletal muscle. The hypotheses were: (1) glycolytic flux would be higher during ischaemic (ISC) compared to free‐flow (FF) muscle contractions, in compensation for reduced oxidative ATP synthesis, and (2) ischaemic muscle fatigue would be related to the accumulation of inhibitory metabolic by‐products rather than to the phosphorylation potential ([ATP]/[ADP][Pi]) of the muscle. Twelve healthy adults (6 men, 6 women) performed six intermittent maximal isometric contractions of the ankle dorsiflexors (12 s contract, 12 s relax), once with intact blood flow and once with local ischaemia by thigh cuff inflation to 220 Torr. Intracellular phosphorous metabolites and pH were measured non‐invasively with magnetic resonance spectroscopy, and rates of ATP synthesis through oxidative phosphorylation, anaerobic glycolysis, and the creatine kinase reaction were determined. The force–time integral declined more during ISC (66 ± 3% initial) than FF (75 ± 2% initial, P= 0.002), indicating greater fatigue in ISC. [ATP] was preserved in both protocols, indicating matching of ATP production and use under both conditions. Glycolytic flux (mm s−1) was similar during FF and ISC (P= 0.16). Total ATP synthesis rate was lower during ISC, despite adjustment for the greater muscle fatigue in this condition (P < 0.001). Fatigue was linearly associated with diprotonated inorganic phosphate (FF r= 0.94 ± 0.01, ISC r= 0.92 ± 0.02), but not phosphorylation potential. These data provide novel evidence that ATP supply and demand in vivo are balanced in human skeletal muscle during ischaemic work, not through higher glycolytic flux, but rather through increased metabolic economy and decreased rates of ATP consumption as fatigue ensues.
Intracellular calcium regulation among subpopulations of rat dorsal root ganglion neurons
Authors: Lu Shao‐Gang , Zhang Xiulin , Gold Michael S.
Published: September 2006

Primary afferent neurons are functionally heterogeneous. To determine whether this functional heterogeneity reflects, in part, heterogeneity in the regulation of the concentration of intracellular Ca2+ ([Ca2+]i), the magnitude and decay of evoked Ca2+ transients were assessed in subpopulations of dorsal root ganglion (DRG) neurons with voltage clamp and fura‐2 ratiometric imaging. To determine whether differences in evoked Ca2+ transients among subpopulations of DRG neurons reflected differences in the contribution of Ca2+ regulatory mechanisms, pharmacological techniques were employed to assess the contribution of influx, efflux, release and uptake pathways. Subpopulations of DRG neurons were defined by cell body size, binding of the plant lectin IB4 and responsiveness to the algogenic compound capsaicin (CAP). Ca2+ transients were evoked with 30 mm K+ or voltage steps to 0 mV. There were marked differences between subpopulations of neurons with respect to both the magnitude and decay of the Ca2+ transient, with the largest and most slowly decaying Ca2+ transients in small‐diameter, IB4‐positive, CAP‐responsive neurons. The smallest and most rapidly decaying transients were in large‐diameter, IB4‐negative and CAP‐unresponsive DRG neurons. These differences were not due to a differential distribution of voltage‐gated Ca2+ currents. However, these differences did appear to reflect a differential contribution of other influx, efflux, release and uptake mechanisms between subpopulations of neurons. These results suggest that electrical activity in subpopulations of DRG neurons will have a differential influence on Ca2+‐regulated phenomena such as spike adaptation, transmitter release and gene transcription. Significantly more activity should be required in large‐diameter non‐nociceptive afferents than in small‐diameter nociceptive afferents to have a comparable influence on these processes.
Interaction between interstitial cells and smooth muscles in the lower urinary tract and penis
Authors: Hashitani Hikaru
Published: September 2006

Smooth muscles in the lower urinary tract and corporal tissue exhibit spontaneous contractile activity which depends on L‐type Ca2+ channels. The mechanism underlying this activity is spontaneous electrical activity which shows varied form and property between these tissues. Recent studies revealed that interstitial cells (ICs) are widely distributed in the genitourinary system, and suggested their involvement in spontaneous muscle activity. ICs in the system are not a simple analogy of interstitial cells of Cajal (ICC) in the gut, which act as electrical pacemaker, but represent variability amongst tissues which may account for individual characteristics of each organ. In the bladder and corporal tissue, where smooth muscle cells are capable of generating spontaneous electrical activity, ICs may modulate smooth muscle activity. ICs in corporal tissue release prostaglandins via cyclooxygenase‐2 (COX‐2) activity and reinforce not only spontaneous but also nerve‐mediated α‐adrenergic contractions. In the bladder, their fundamental role in the integration of signals between populations of cells has been proposed, and thus changes in ICs may contribute to an overactive bladder, a pathological condition which results from increased excitability in detrusor smooth muscles. In the urethra, ICs may act as electrical pacemakers as do ICC. However, overall contractility of urethral smooth muscles does not necessarily rely on pacemaking of ICs, and thus some population of smooth muscles may also have their own excitability.
Complex interplay between glutamate receptors and intracellular Ca2+ stores during ischaemia in rat spinal cord white matter
Authors: Ouardouz Mohamed , Malek Sameh , Coderre Elaine , Stys Peter K.
Published: September 2006

Electrophysiological recordings of propagated compound action potentials (CAPs) and axonal Ca2+ measurements using confocal microscopy were used to study the interplay between AMPA receptors and intracellullar Ca2+ stores in rat spinal dorsal columns subjected to in vitro combined oxygen and glucose deprivation (OGD). Removal of Ca2+ or Na+ from the perfusate was protective after 30 but not 60 min of OGD. TTX was ineffective with either exposure, consistent with its modest effect on ischaemic depolarization. In contrast, AMPA antagonists were very protective, even after 60 min of OGD where 0Ca2++ EGTA perfusate was ineffective. Similarly, blocking ryanodine receptor‐mediated Ca2+ mobilization from internal stores (0Ca2++ nimodipine or 0Ca2++ ryanodine), or inositol 1,4,5‐trisphosphate (IP3)‐dependent Ca2+ release (block of group 1 metabotropic glutamate receptors with 1‐aminoindan‐1,5‐dicarboxylic acid, inhibition of phospholipase C with U73122 or IP3 receptor block with 2APB; each in 0Ca2+) were each very protective, with the combination resulting in virtually complete functional recovery after 1 h OGD (97 ± 32% CAP recovery versus 4 ± 6% in artificial cerebrospinal fluid). AMPA induced a rise in Ca2+ concentration in normoxic axons, which was greatly reduced by blocking ryanodine receptors. Our data therefore suggest a novel and surprisingly complex interplay between AMPA receptors and Ca2+ mobilization from intracellular Ca2+ stores. We propose that AMPA receptors may not only allow Ca2+ influx from the extracellular space, but may also significantly influence Ca2+ release from intra‐axonal Ca2+ stores. In dorsal column axons, AMPA receptor‐dependent mechanisms appear to exert a greater influence than voltage‐gated Na+ channels on functional outcome following OGD.
Interstitial cells of Cajal at the clinical and scientific interface
Authors: Sanders Kenton M.
Published: September 2006

Considerable work over the past two decades has determined that interstitial cells of Cajal (ICC) serve as pacemaker cells, conduits for active transmission of electrical slow waves, sites of innervation by peripheral motor neurons, and mechanotransducers. While most of the physiology of ICC has been learned from studies of the cells within the gastrointestinal tract, ICC are found in a variety of smooth muscle tissues and may have analogous or novel physiological functions in those organs. Clinical investigations of muscles from patients with a variety of gastrointestinal motility disorders have raised the exciting possibility that loss of ICC may be responsible for the development of motor dysfunction. This review discusses the development of ICC, the kinds of human disorders in which ICC loss may be important, what factors regulate the ICC phenotype, and what therapeutic approaches might be utilized to restore or regenerate ICC. This field is primed for translational discoveries. ICC are responsible for critical physiological functions in smooth muscle tissues, they are lost in pathophysiological conditions, and it will be important now to decipher the conditions that are responsible for ICC loss and develop new therapies to relieve patients of this problem. Success in this endeavour might improve the quality of life for millions of patients.
Factors modifying the frequency of spontaneous activity in gastric muscle
Authors: Suzuki H. , Kito Y. , Hashitani H. , Nakamura E.
Published: September 2006

The cellular mechanisms that determine the frequency of spontaneous activity were investigated in gastric smooth muscles isolated from the guinea‐pig. Intact antral muscle generated slow waves periodically; the interval between slow waves was decreased exponentially by depolarization of the membrane to reach a steady interval value of about 7 s. Isolated circular muscle bundles produced slow potentials spontaneously or were evoked by depolarizing current stimuli. Evoked slow potentials appeared in an all‐or‐none fashion, with a refractory period of ∼2–3 s. Low concentrations of chemicals that modify intracellular signalling revealed that the refractory period was causally related to the activity of protein kinase C (PKC). Activation of PKC increased and inhibition of PKC activity decreased the frequency of slow potentials. Chemicals that inhibit mitochondrial functions reduced the frequency of slow waves. Inhibition of internal Ca2+‐store activity decreased the amplitude, but not the frequency of slow potentials, suggesting that the amplitude is causally related to Ca2+ release from the internal store. The results suggest that changes in [Ca2+]i caused by the activity of mitochondria may play a key role in determining the frequency of spontaneous activity in gastric pacemaker cells.
Cytosolic energy reserves determine the effect of glycolytic sugar phosphates on sarcoplasmic reticulum Ca2+ release in cat ventricular myocytes
Authors: Zima Aleksey V. , Kockskämper Jens , Blatter Lothar A.
Published: September 2006

Localization of glycolytic enzymes in close proximity to Ca2+ transport systems of the sarcoplasmic reticulum (SR) in cardiac cells suggests an important functional role for glycolysis in intracellular [Ca2+] regulation and, consequently, excitation–contraction coupling. Here, we investigated the mechanisms of regulation of SR Ca2+ release by glycolytic sugar phosphate intermediates in cat ventricular myocytes. Experiments with permeabilized myocytes revealed that with normal cytosolic energy reserves (mm: ATP 5, ADP 0.01, phosphocreatine (CrP) 10) fructose‐1,6‐bisphosphate (FBP; 1 mm) and fructose‐6‐phosphate (F6P; 1 mm) caused a transient increase of Ca2+ spark frequency by 62 and 42%, respectively. This effect of sugar phosphates was associated with a 13% decrease in SR Ca2+ load. Pretreatment of the cells with an inhibitor of glycolysis, iodoacetate (IAA; 0.5 mm), did not prevent the effects of FBP and F6P on Ca2+ sparks. Recording of single ryanodine receptor (RyR) channel activity indicated that FBP and F6P significantly increased RyR open probability. Reduction of cytosolic energy reserves decreased Ca2+ spark activity. Increasing [ADP] to 0.4 mm or removal of CrP ([ATP] was kept constant) caused a slowly developing decrease of Ca2+ spark frequency by 29 and 42%, respectively. Changing [ADP] and [CrP] simultaneously decreased Ca2+ spark frequency by 66%. This inhibition of Ca2+ sparks was associated with a 40% decrease in SR Ca2+ load. The subsequent addition of FBP (1 mm) partially restored Ca2+ spark frequency and SR Ca2+ load. This recovery of Ca2+ sparks was blocked completely by IAA. These data suggest that at physiological ATP, ADP and CrP levels accumulation of sugar phosphates from glycolysis can stimulate SR Ca2+ release. This effect does not require the activity of downstream glycolytic enzymes, but rather is the result of direct activation of RyRs. However, under conditions associated with depletion of cellular energy reserves (e.g. myocardial ischaemia), ATP generated from glycolysis may play an important role in maintaining myocardial Ca2+ homeostasis by improving SR Ca2+ uptake.
The self‐regulating nature of spontaneous synchronized activity in developing mouse cortical neurones
Authors: McCabe Annette K. , Chisholm Sarah L. , Picken‐Bahrey Heidi L. , Moody William J.
Published: September 2006

Waves of spontaneous electrical activity that are highly synchronized across large populations of neurones occur throughout the developing mammalian central nervous system. The stages at which this activity occurs are tightly regulated to allow activity‐dependent developmental programmes to be initiated correctly. What determines the onset and cessation of spontaneous synchronous activity (SSA) in a particular region of the nervous system, however, remains unclear. We have tested the hypothesis that activity itself triggers developmental changes in intrinsic and circuit properties that determine the stages at which SSA occurs. To do this we exposed cultured slices of mouse neocortex to tetrodotoxin (TTX) to block SSA, which normally occurs between embryonic day 17 (E17) and postnatal day 3 (P3). In control cultured slices, SSA rarely occurs after P3. In TTX‐treated slices, however, SSA was generated from P3 (the day of TTX removal) until at least P10. This indicates that in the absence of spontaneous activity, the mechanisms that normally determine the timing of SSA are not initiated, and that a compensatory response occurs that shifts the time of SSA occurrence to later developmental stages.
Potentiation of mouse vagal afferent mechanosensitivity by ionotropic and metabotropic glutamate receptors
Authors: Slattery James A. , Page Amanda J. , Dorian Camilla L. , Brierley Stuart M. , Blackshaw L. Ashley
Published: September 2006

Glutamate acts at central synapses via ionotropic (iGluR – NMDA, AMPA and kainate) and metabotropic glutamate receptors (mGluRs). Group I mGluRs are excitatory whilst group II and III are inhibitory. Inhibitory mGluRs also modulate peripherally the mechanosensitivity of gastro‐oesophageal vagal afferents. Here we determined the potential of excitatory GluRs to play an opposing role in modulating vagal afferent mechanosensitivity, and investigated expression of receptor subunit mRNA within the nodose ganglion. The responses of mouse gastro‐oesophageal vagal afferents to graded mechanical stimuli were investigated before and during application of selective GluR ligands to their peripheral endings. Two types of vagal afferents were tested: tension receptors, which respond to circumferential tension, and mucosal receptors, which respond only to mucosal stroking. The selective iGluR agonists NMDA and AMPA concentration‐dependently potentiated afferent responses. Their corresponding antagonists AP‐5 and NBQX alone attenuated mechanosensory responses as did the non‐selective antagonist kynurenate. The kainate selective agonist SYM‐2081 had minor effects on mechanosensitivity, and the antagonist UBP 302 was ineffective. The mGluR5 antagonist MTEP concentration‐dependently inhibited mechanosensitivity. Efficacy of agonists and antagonists differed on mucosal and tension receptors. We conclude that excitatory modulation of afferent mechanosensitivity occurs mainly via NMDA, AMPA and mGlu5 receptors, and the role of each differs according to afferent subtypes. PCR data indicated that all NMDA, kainate and AMPA receptor subunits plus mGluR5 are expressed, and are therefore candidates for the neuromodulation we observed.
Elementary model of sprite igniting electric fields
Authors: Fullekrug Martin
Published: August 2006

Sprites are a recently discovered exotic kind of lightning above thunderstorms. An analytic model of sprite igniting electric fields is developed to describe the essence of sprite physics. The proposed model uses typical parameters of particularly intense positive lightning discharges inside thunderclouds which cause the sprites. The sensitivity of the results with respect to the natural variability of the model parameters is discussed.
Irreversible Organic Crystalline Chemistry Monitored in Real Time
Authors: Poulin Peter R. , Nelson Keith A.
Published: September 2006

Because multiple laser shots are typically required to monitor ultrafast photochemical reaction dynamics, sample depletion and product accumulation have greatly restricted the range of substrates and structural environments amenable to study. By implementing a two-dimensional spatial delay gradient across the profile of a femtosecond probe pulse, we can monitor in a single laser shot organic crystalline reaction dynamics despite the formation of permanent photoproducts that cannot be conveniently removed. We monitored the photolysis of the triiodide anion, I
3
−
, and subsequent recombination or relaxation of its reaction products, in three very different pure organic molecular crystals. The experimental results and associated molecular dynamics simulations illustrate the intimate connection between lattice structure and reaction dynamics, highlighting the role of lattice constraints in directing phase-coherent geminate recombination of photofragments within a crystalline reaction cage.
Cancer Regression in Patients After Transfer of Genetically Engineered Lymphocytes
Authors: Morgan Richard A. , Dudley Mark E. , Wunderlich John R. , Hughes Marybeth S. , Yang James C. , Sherry Richard M. , Royal Richard E. , Topalian Suzanne L. , Kammula Udai S. , Restifo Nicholas P. , Zheng Zhili , Nahvi Azam , de Vries Christiaan R. , Rogers-Freezer Linda J. , Mavroukakis Sharon A. , Rosenberg Steven A.
Published: September 2006

Through the adoptive transfer of lymphocytes after host immunodepletion, it is possible to mediate objective cancer regression in human patients with metastatic melanoma. However, the generation of tumor-specific T cells in this mode of immunotherapy is often limiting. Here we report the ability to specifically confer tumor recognition by autologous lymphocytes from peripheral blood by using a retrovirus that encodes a T cell receptor. Adoptive transfer of these transduced cells in 15 patients resulted in durable engraftment at levels exceeding 10% of peripheral blood lymphocytes for at least 2 months after the infusion. We observed high sustained levels of circulating, engineered cells at 1 year after infusion in two patients who both demonstrated objective regression of metastatic melanoma lesions. This study suggests the therapeutic potential of genetically engineered cells for the biologic therapy of cancer.
Solid Ammonium Sulfate Aerosols as Ice Nuclei: A Pathway for Cirrus Cloud Formation
Authors: Abbatt J. P. D. , Benz S. , Cziczo D. J. , Kanji Z. , Lohmann U. , Möhler O.
Published: September 2006

Laboratory measurements support a cirrus cloud formation pathway involving heterogeneous ice nucleation by solid ammonium sulfate aerosols. Ice formation occurs at low ice-saturation ratios consistent with the formation of continental cirrus and an interhemispheric asymmetry observed for cloud onset. In a climate model, this mechanism provides a widespread source of ice nuclei and leads to fewer but larger ice crystals as compared with a homogeneous freezing scenario. This reduces both the cloud albedo and the longwave heating by cirrus. With the global ammonia budget dominated by agricultural practices, this pathway might further couple anthropogenic activity to the climate system.
A New Bis-Tröger's Base: Synthesis, Spectroscopy, Crystal Structure and Isomerization
Authors: Valík Martin , Matějka Pavel , Herdtweck Eberhardt , Král Vladimír , Dolensky Bohumil
Published: September 2006

A new bis-Tröger's base was prepared from a tetraamine precursor as a mixture of two diastereoisomers. One of the isomers has a chair-like geometry, and the other possesses a boat-like geometry, embodying molecular tweezers. A one-pot preparation of bis-TB isomers and their interconversion under acid conditions was also studied. Structures of both isomers were confirmed by single-crystal X-ray diffraction. Extensive spectroscopic data, including 1H and 13C NMR, IR and Raman spectra of the isomers, are given.
Synthesis and Properties of 2-Guanidinopurines
Authors: Česnek Michal , Masojídková Milena , Holý Antonín , Šolínová Veronika , Koval Dušan , Kašička Václav
Published: September 2006

2-Guanidinopurines were prepared as derivatives of 2,6-diamino-9-[2-(phosphonomethoxy)ethyl]-9H-purine (PMEDAP) (1), which shows an important antiviral activity. It completes earlier described synthesis of 6-guanidinopurine derivatives. The title compounds were obtained by the reaction of the corresponding 2-chloropurines with guanidine. 2- And 6-guanidinopurines were used as model compounds for determination of dissociation constants (pKa) of their ionogenic groups by capillary zone electrophoresis. The pKa values of ionogenic groups of the above compounds were compared with those of the corresponding aminopurines. The pKa of guanidino group at the purine moiety varies from 7.77 to 10.32. There is no protonation of N1-position in contrast to aminopurines. None of these compounds showed any antiviral activity.
THE HILBERT SCHEME OF DEGREE TWO CURVES AND CERTAIN ROPES
Authors: NAGEL UWE , NOTARI ROBERTO , SPREAFICO MARIA LUISA
Published: September 2006

We study families of ropes of any codimension that are supported on lines. We construct suitable smooth parameter spaces and conclude that all ropes of fixed degree and genus lie in the same component of the corresponding Hilbert scheme. We show that this component is generically smooth if the genus is small enough unless the characteristic of the ground field is two and the curves under consideration have degree two. In this case the component is non-reduced.
ON A CONJECTURE OF BELTRAMETTI–SOMMESE FOR POLARIZED 3-FOLDS
Authors: FUKUMA YOSHIAKI
Published: September 2006

Let (X, L) be a polarized manifold of dimension 3. In this paper, we consider a lower bound for h0(KX+ 2L). We prove that h0(KX+ 2L) > 0 if KX+ 2L is nef, which is a conjecture of Beltrametti–Sommese for polarized 3-folds. Moreover we classify polarized 3-folds (X, L) with h0(KX+ 2L) = 1 under the assumption that KX+ 2L is nef.
FERMIONIC ZERO MODES IN GAUGE AND GRAVITY BACKGROUNDS ON T2
Authors: DUAN YISHI , LIU YUXIAO , WANG YONGQIANG
Published: September 2006

Here we study fermionic zero modes in gauge and gravity backgrounds taking a two-dimensional compact manifold T2 as extra dimensions. The result is that there exist massless Dirac fermions which have normalizable zero modes under quite general assumptions about these backgrounds on the bulk. Several special cases of gauge background on the torus are discussed and some simple fermionic zero modes are obtained.
EMPIRICAL DETERMINATION OF THRESHOLD PARTIAL WAVE AMPLITUDES FOR pp → ppω
Authors: RAMACHANDRAN G. , BALASUBRAMANYAM J. , VIDYA M. S. , VENKATARAYA
Published: September 2006

Using the model-independent irreducible tensor approach to ω production in pp collisions, we show theoretically that it is advantageous to measure experimentally the polarization of ω, in addition to the proposed experimental study employing a polarized beam on a polarized target.
QUARK MATTER IN NEUTRON STARS: AN APERÇU
Authors: JAIKUMAR PRASHANTH , REDDY SANJAY , STEINER ANDREW W.
Published: September 2006

The existence of deconfined quark matter in the superdense interior of neutron stars is a key question that has drawn considerable attention over the past few decades. Quark matter can comprise an arbitrary fraction of the star, from 0 for a pure neutron star to 1 for a pure quark star, depending on the equation of state of matter at high density. From an astrophysical viewpoint, these two extreme cases are generally expected to manifest different observational signatures. An intermediate fraction implies a hybrid star, where the interior consists of mixed or homogeneous phases of quark and nuclear matter, depending on surface and Coulomb energy costs, as well as other finite size and screening effects. In this review, we discuss what we can deduce about quark matter in neutron stars in light of recent exciting developments in neutron star observations. We state the theoretical ideas underlying the equation of state of dense quark matter, including color superconducting quark matter. We also highlight recent advances stemming from re-examination of an old paradigm for the surface structure of quark stars and discuss possible evolutionary scenarios from neutron stars to quark stars, with emphasis on astrophysical observations.
BLACK HOLES AND SOLITONS OF THE NONLINEAR ISOVECTOR MODEL
Authors: RIAZI NEMATOLLAH , NIAD HASSAN , HENDI SEYED HOSSEIN
Published: September 2006

We formulate the nonlinear isovector model in a curved background and calculate the spherically symmetric solutions for weak and strong coupling regimes. The question whether gravity has appreciable effects on the structure of solitons will be examined, in the framework of the calculated solutions, by comparing the flat-space and curved-space solutions. It turns out that in the strong coupling regime, gravity has essential effects on the solutions. It is also shown that the asymptotic form of the metric conforms with that of the charged Reissner–Nordstrom metric. The dimensionless coupling constant of the model has a limit, beyond which a horizon appears in the solutions, indicating the presence of black hole solutions.
SCALAR SECTOR IN THE MINIMAL SUPERSYMMETRIC 3-3-1 MODEL
Authors: RODRIGUEZ M. C.
Published: September 2006

We consider the minimal supersymmetric extension of the 3-3-1 model and we study the mass spectra in the scalar sector of this model without the antisextet. We show that all our lightest scalars are in agreement with the experimental limits.
CHIRAL CONSTITUENT QUARK MODEL AND THE COUPLING STRENGTH OF η′
Authors: DAHIYA HARLEEN , GUPTA MANMOHAN , RANA J. M. S.
Published: September 2006

Using the latest data pertaining to [Formula: see text] asymmetry and the spin polarization functions, detailed implications of the possible values of the coupling strength of the singlet Goldstone boson η′ have been investigated in the χCQM with configuration mixing. Using Δu, Δ3, [Formula: see text] and [Formula: see text], the possible ranges of the coupling parameters a, α2a, β2a and ζ2a, representing respectively the probabilities of fluctuations to pions, K, η and η′, are shown to be 0.10 ≲ a ≲ 0.14, 0.2 ≲ α ≲ 0.5, 0.2 ≲ β ≲ 0.7 and 0.10 ≲|ζ|≲ 0.70. To further constrain the coupling strength of η′, detailed fits have been obtained for spin polarization functions, quark distribution functions and baryon octet magnetic moments corresponding to the following sets of parameters: a = 0.1, α = 0.4, β = 0.7, |ζ| = 0.65 (Case I); a = 0.1, α = 0.4, β = 0.6, |ζ| = 0.70 (Case II); a = 0.14, α = 0.4, β = 0.2, ζ = 0 (Case III) and a = 0.13, α = β = 0.45, |ζ| = 0.10 (Case IV). Case I represents the calculations where a is fixed to be 0.1, in accordance with earlier calculations, whereas other parameters are treated free and the Case IV represents our best fit. The fits clearly establish that a small nonzero value of the coupling of η′ is preferred over the higher values of η′ as well as when ζ = 0, the latter implying the absence of η′ from the dynamics of χCQM. Our best fit achieves an overall excellent fit to the data, in particular the fit for Δu, Δd, Δ8 as well as the magnetic moments μn, μΣ-, μΣ+ and μΞ- is almost perfect, the μΞ- being a difficult case for most of the similar calculations.
ON A PETROV-TYPE D HOMOGENEOUS SOLUTION
Authors: RADU EUGEN
Published: September 2006

We present a new two-parameter family of solutions for Einstein gravity with negative cosmological constant in 2+1 dimensions. These solutions are obtained by squashing the Anti-de Sitter geometry along one direction and posses four Killing vectors. Global properties as well as the four-dimensional generalization are discussed, followed by the investigation of the geodesic motion. A simple global embedding of these spaces as the intersection of four quadratic surfaces in a seven-dimensional space is obtained. We also argue that these geometries describe the boundary of a four-dimensional nutty-bubble solution and are relevant in the context of AdS/CFT correspondence.
EXOTIC LOW DENSITY FERMION STATES IN THE TWO MEASURES FIELD THEORY: NEUTRINO DARK ENERGY
Authors: GUENDELMAN E. I. , KAGANOVICH A. B.
Published: September 2006

There exist field theory models where the fermionic energy–momentum tensor contains a term proportional to [Formula: see text] which may contribute to the dark energy. We show that this new field theory effect can be achieved in the Two Measures Field Theory (TMT) in the cosmological context. TMT is an alternative gravity and matter field theory where the gravitational interaction of fermionic matter is reduced to that of General Relativity when the energy density of the fermion matter is much larger than the dark energy density. In this case also the fifth force problem is solved automatically. In the opposite limit, where the magnitudes of fermionic energy density and scalar field dark energy density become comparable, nonrelativistic fermions can participate in the cosmological expansion in a very unusual manner. Some of the features of such Cosmo-Low-Energy-Physics (CLEP) states are studied in a toy model of the late time universe filled with homogeneous scalar field and uniformly distributed nonrelativistic neutrinos, and the following results are obtained: neutrino mass increases as m ∝ a3/2 (a is the scale factor); the proportionality factor in the noncanonical contribution to the neutrino energy–momentum tensor (proportional to the metric tensor) approaches a constant as a(t) → ∞ and therefore the noncanonical contribution to the neutrino energy density dominates over the canonical one ~ m/a3 ~ a-3/2 at the late enough universe; hence the neutrino gas equation-of-state approaches w = -1, i.e. neutrinos in the CLEP regime behave as a sort of dark energy as a → ∞; the equation-of-state for the total (scalar field + neutrino) energy density and pressure also approaches w = -1 in the CLEP regime; besides the total energy density of such universe is less than it would be in the universe filled with the scalar field alone. An analytic solution is presented. A domain structure of the dark energy seems to be possible. We speculate that decays of the CLEP state neutrinos may be both an origin of cosmic rays and responsible for a late super-acceleration of the universe. In this sense the CLEP states exhibit simultaneously new physics at very low densities and for very high particle masses.
U(2) PROJECTORS AND 'T HOOFT–POLYAKOV MONOPOLES ON A FUZZY SPHERE
Authors: VALTANCOLI P.
Published: September 2006

We show how to generalize our method, based on projective modules and matrix models, which enabled us to derive noncommutative monopoles on a fuzzy sphere, to the non-Abelian case, recovering known results in literature. We then discuss a possible candidate for deforming the commutative Chern class to the noncommutative case.
EXCLUSIVE BARYONIC B DECAYS CIRCA 2005
Authors: CHENG HAI-YANG
Published: September 2006

The status of exclusive two-body and three-body baryonic B decays is reviewed. The threshold enhancement effect in the dibaryon invariant mass and the angular distributions in the dibaryon rest frame are stressed and explained. Weak radiative baryonic B decays mediated by the electromagnetic penguin process b→sγ are discussed. Puzzles with the correlation observed in [Formula: see text] decay and the unexpectedly large rate observed for [Formula: see text] are examined. The former may indicate that the [Formula: see text] system is produced through some intermediate states, while the latter implies the failure of naive factorization for [Formula: see text] modes and may hint at the importance of final-state rescattering effects.