bluuebunny/crossref_metadata_2025 huggingface dataset:
In vivo Distribution of Bismuth in the Mouse Brain: Influence of Long‐Term Survival and Intracranial Placement on the Uptake and Transport of Bismuth in Neuronal Tissue
Authors: Larsen Agnete , Stoltenberg Meredin , Søndergaard Chris , Bruhn Mikkel , Danscher Gorm
Published: August 2005

Abstract: Bismuth is used for a multitude of industrial purposes and has partly replaced toxic heavy metals such as lead and mercury in e.g. lubricants and shotgun pellets. In medicine, bismuth‐compounds have long been used to remedy gastrointestinal disorders; lately in combination with antibiotics to treat Helicobacter pylori associated peptic ulcers. An epidemic episode of bismuth‐induced encephalopathy in France in the 1970s revealed the neurotoxic potential of bismuth. This incidence, involving almost 1000 patients, remains unexplained and the contribution of other factors besides bismuth has been postulated. Recently an autometallographic technique made it possible to detect bismuth in morphologically intact tissue. In the present study, autometallographicly detectable bismuth was seen throughout the brain following intraperitoneal and intracranial exposure. The neuronal staining pattern seems highly organized with some areas heavily stained and others with low or no staining. Long‐term (8 months) intraperitoneal exposure led to higher bismuth uptake than short‐term (2 weeks) exposure. Following both intraperitoneal and intracranial exposure, high amounts of bismuth were found in the reticular and hypothalamic nuclei, in the oculomotor and hypoglossal nuclei and in Purkinje cells. Within the central nervous system (CNS) retrograde axonal transport was seen after intracranial bismuth exposure. Axonal transport seems to influence the distribution of bismuth as the highest uptake of bismuth after intraperitoneal exposure was seen in the facial and the trigeminal motor nuclei, i.e. neurones with processes outside the blood‐brain barrier, whereas these nuclei contained no bismuth following ic exposure. Ultrastructurally, accumulation of bismuth was seen in lysosomes.
Parachlorophenylalanine Exacerbates Oxidative Stress Induced by Gentamicin in Rats
Authors: Muñoz‐Castañeda Juan R. , Montilla Pedro , Muñoz Maria C. , Bujalance Immaculada , Muntané Jordi , Túnez Isaac
Published: August 2005

Abstract: The present work studies the effect of parachlorophenylalanine (PCPA, 200 mg/kg intraperitoneally/48 hr for 7 days) on the oxidative stress and nephropathy induced by gentamicin (80 mg/kg intraperitoneally/daily for 7 days) in Wistar rats. The effect of PCPA on lipid peroxidation products and reduced glutathione content in renal and brain tissue, as well as on 5HT content in brain was assessed. Catalase and superoxide dismutase activities were determined in brain tissue. Blood urea nitrogen and creatinine in plasma and total protein content in urine were also measured. Gentamicin caused significant increases in proteinuria, non‐protein nitrogen compounds and lipid peroxidation markers, together with decreases in both reduced glutathione content in renal and brain tissue and enzymatic activities in brain homogenates. PCPA harnessed the effect of gentamicin in the brain and the kidney, while PCPA alone induced brain oxidative stress. These results support the prooxidant action of PCPA in brain tissue and its capacity to exacerbate the oxidative stress and renal dysfunction induced by gentamicin, as well as the possible antioxidant property of serotonin.
Effects of Amifostine on Glycerol‐Pretreated Rabbit Kidneys
Authors: Barun Süreyya , Ertoy Dilek , Dileköz Ergin , Müftüogˇlu Sevda , Erten Yasemin , Sucak Gülsan , Bali Musa , Tekeli Nurçin , Sarıogˇlu Yusuf , Ercan Zeynep Sevim
Published: August 2005

Abstract: Glycerol‐induced acute renal failure is an experimental model for myoglobinuric nephropathy. Amifostine is a cytoprotective agent which scavenges the free radicals. Since there is enhanced production of reactive oxygen metabolites in glycerol‐induced acute renal failure, we wanted to examine whether amifostine has a protective role against vascular reactivity and histological changes in kidneys isolated from glycerol‐pretreated rabbits. Perfusion pressure was recorded from kidneys obtained from rabbits injected with glycerol 3 hr before the experiments and from glycerol‐pretreated and non‐pretreated rabbits injected with amifostine 30 min. before the experiments. Acetylcholine‐induced (10−8‐10−5 M) vasodilatation was tested following the construction of submaximal vasoconstriction by phenylephrine. Histological investigation was performed using light microscope. Acetylcholine‐induced vasodilatation was found to be significantly decreased in glycerol, glycerol+amifostine and amifostine groups compared to controls at all concentrations. Reduction in acetylcholine‐induced vasodilation was more prominent in amifostine group compared to amifostine+glycerol group. There was histological renal damage in all experimental groups and this damage was more pronounced in glycerol+amifostine group. In conclusion, contrary to expectation, amifostine per se led to histological damage and potentiated the histological damage caused by glycerol and produced a decrease in acetylcholine‐induced vasodilatation. The mechanisms by which amifostine exerts its effects are not known.
Near‐Fatal Amitraz Intoxication: The Overlooked Pesticide
Authors: Elinav Eran , Shapira Yami , Ofran Yishai , Hassin Tal , Ben‐Dov Iddo Z.
Published: August 2005

Abstract: Amitraz is commonly used in agricultural industries throughout the world as a farm‐animal insecticide. Despite its widespread use, amitraz intoxication is extremely rare and mainly occurs through accidental ingestion by young children. Severe, life‐threatening amitraz intoxication in adults is very rarely recognized and reported. Described herein is a previously healthy 54‐year‐old patient who accidentally ingested a mouthful of liquid amitraz concentrate, and rapidly developed life‐threatening clonidine‐like overdose syndrome, manifested as nausea, vomiting, hypotension, bradycardia, bradypnoea, and deep coma. Supportive treatment, including mechanical ventilation, and atropine administration resulted in full recovery within 48 hr. Very few cases of near‐fatal amitraz poisoning in adults have been described in the medical literature, leading to low awareness of physicians in general practice to the potential toxicity of amitraz. As a consequence, cases of amitraz poisoning are not recognised and therefore erroneously treated as the much more commonly recognized organophosphate and carbamate intoxication. In our discussion, we review the clinical and laboratory manifestations of amitraz poisoning, including clinical hints that aid in the recognition of this often‐overlooked diagnosis. Differentiation of amitraz intoxication from the much more commonly seen pesticide‐related organophosphate and carbamate intoxication is of utmost importance, in order to avoid erroneous, unnecessary, and often dangerous treatment.
Emission line variability of RS Ophiuchi
Authors: Zamanov R. K. , Bode M. F. , Tomov N. A. , Porter J. M.
Published: August 2005

We report that the Hα emission line of RS Oph was strongly variable during our 2004 observations on a time-scale of one month. The line consisted of both a double-peaked central narrow component [full width at half-maximum (FWHM) ∼ 220 km s−1] and a strongly variable broad one (FWHM > 2000 km s−1). The base of the Hα line was very broad, with full width at zero intensity ≈ 4600 km s−1 on all spectra from 1986 to 2004. The variability of the broad component extends from −2000 to +2000 km s−1. Most probably this is due either to blobs ejected from the white dwarf (with a typical blob mass estimated to be ∼10−10 M⊙) or to a variable accretion disc wind. We also detected variability of the He iiλ4686 line on a time-scale shorter than 1 d. The possible origin is discussed.
The metal enrichment of elliptical galaxies in hierarchical galaxy formation models
Authors: Nagashima Masahiro , Lacey Cedric G. , Okamoto Takashi , Baugh Carlton M. , Frenk Carlos S. , Cole Shaun
Published: August 2005

We investigate the metal enrichment of elliptical galaxies in the framework of hierarchical models of galaxy formation. The semi-analytical model we use, which has been used to study the metal enrichment of the intracluster medium (ICM) by Nagashima et al., includes the effects of flows of gas and metals both into and out of galaxies and the processes of metal enrichment due to both type Ia and type II supernovae. We adopt a solar neighbourhood initial mass function (IMF) for star formation in discs, but consider models in which starbursts have either a solar neighbourhood IMF or a top-heavy IMF. We find that the α-element abundance in ellipticals is consistent with observed values only if the top-heavy IMF is used. This result is consistent with our previous study on the metal enrichment of the ICM. We also discuss the abundance ratio of α elements to iron as a function of velocity dispersion and metallicity. We find that models with a top-heavy IMF match the α/Fe ratios observed in typical L* ellipticals, but none of the models reproduces the observed increase of α/Fe with velocity dispersion.
Productivity‐diversity relationships for plants, bryophytes, lichens, and polypore fungi in six northern forest landscapes
Authors: Gjerde Ivar , Sætersdal Magne , Rolstad Jørund , Olaf Storaunet Ken , Blom Hans H. , Gundersen Vegard , Heegaard Einar
Published: August 2005

We investigated the relationship between site productivity and diversity of vascular plants, bryophytes, lichens, and polypore fungi in forests based on species richness data in 0.25 ha forest plots (grain size), selected from six 150–200 ha study areas (focus), and spanning over a latitudinal distance of 1350 km (extent) in Norway. We 1) searched for prevailing productivity‐diversity relationships (PDRs), 2) compared PDRs among taxonomic groups and species found in different micro‐habitats, and 3) investigated the effect of increasing plot (grain) size on PDRs. Using vegetation types as a surrogate for site productivity, we found a general pattern of increasing species richness with site productivity. On average total species richness doubled with a ten‐fold increase in productivity. Lichens PDRs stood out as less pronounced and more variable than for other species groups investigated. PDRs of species associated with downed logs tended to level off at high‐productive sites, a pattern interpreted as an effect of disturbance. Increasing the grain size >10‐fold did not change the proportional difference in species richness between sites with high and low productivity.
Nitric oxide synthase inhibition reduces the O2 cost of force development in rat hindlimb muscles pump perfused at matched convective O2 delivery
Authors: Krause Daniel J. , Hagen Jason L. , Kindig Casey A. , Hepple Russell T.
Published: August 2005

Nitric oxide (NO) is a physiological mediator of skeletal muscle function. Specifically, NO affects cellular respiration and muscle contractility; however, the reduced blood flow and convective O2 delivery that result from impaired vasodilatation when NO synthase (NOS) is inhibited in vivo have obscured past interpretations of the effects of NO. Therefore, we studied the effect of NOS inhibition in an in situ pump‐perfused rat hindlimb to test the hypothesis that NOS inhibition would improve contractile and aerobic metabolic performance. Pump perfusion permitted matching of convective O2 delivery (516 ± 16 μmol O2 min−1 (100 g)−1; mean ±s.e.m.) between groups, allowing us to investigate the effects of NOS inhibition independent of this variable. Three groups were studied. The perfusate of one group was treated with both adenosine (0.01 mm) and the NOS inhibitor, Nω‐nitro‐l‐arginine methyl ester (l‐NAME; 1 mm). Adenosine is a vasodilator that can act through both NO‐dependent and ‐independent pathways; the NO‐independent vasodilatory action of adenosine allowed us to match the perfusion rate and convective O2 delivery in this l‐NAME group to those of the other groups. In the second group the perfusate was treated with adenosine only (Ado). In the third group the perfusate received no treatment and served as a control (Con). Oxygen consumption (
) was on average 26 and 14% lower during the contraction bout in l‐NAME and Ado, respectively, versus Con. In Ado, lactate efflux was similar to Con and force was reduced in proportion to
versus Con, whereas l‐NAME was associated with a 32% lower lactate efflux and similar force to Con. Therefore, the lower
:force development ratio in the l‐NAME group demonstrates that the O2 cost of force development is reduced by NOS inhibition independent of convective O2 delivery.
Orexinergic projections to the cat midbrain mediate alternation of emotional behavioural states from locomotion to cataplexy
Authors: Takakusaki Kaoru , Takahashi Kazumi , Saitoh Kazuya , Harada Hirofumi , Okumura Toshikatsu , Kayama Yukihiko , Koyama Yoshimasa
Published: August 2005

Orexinergic neurones in the perifornical lateral hypothalamus project to structures of the midbrain, including the substantia nigra and the mesopontine tegmentum. These areas contain the mesencephalic locomotor region (MLR), and the pedunculopontine and laterodorsal tegmental nuclei (PPN/LDT), which regulate atonia during rapid eye movement (REM) sleep. Deficiencies of the orexinergic system result in narcolepsy, suggesting that these projections are concerned with switching between locomotor movements and muscular atonia. The present study characterizes the role of these orexinergic projections to the midbrain. In decerebrate cats, injecting orexin‐A (60 μm to 1.0 mm, 0.20–0.25 μl) into the MLR reduced the intensity of the electrical stimulation required to induce locomotion on a treadmill (4 cats) or even elicit locomotor movements without electrical stimulation (2 cats). On the other hand, when orexin was injected into either the PPN (8 cats) or the substantia nigra pars reticulata (SNr, 4 cats), an increased stimulus intensity at the PPN was required to induce muscle atonia. The effects of orexin on the PPN and the SNr were reversed by subsequently injecting bicuculline (5 mm, 0.20–0.25 μl), a GABAA receptor antagonist, into the PPN. These findings indicate that excitatory orexinergic drive could maintain a higher level of locomotor activity by increasing the excitability of neurones in the MLR, while enhancing GABAergic effects on presumably cholinergic PPN neurones, to suppress muscle atonia. We conclude that orexinergic projections from the hypothalamus to the midbrain play an important role in regulating motor behaviour and controlling postural muscle tone and locomotor movements when awake and during sleep. Furthermore, as the excitability is attenuated in the absence of orexin, signals to the midbrain may induce locomotor behaviour when the orexinergic system functions normally but elicit atonia or narcolepsy when the orexinergic function is disturbed.
Propagation in the transverse tubular system and voltage dependence of calcium release in normal and mdx mouse muscle fibres
Authors: Woods Christopher E. , Novo David , DiFranco Marino , Capote Joana , Vergara Julio L.
Published: August 2005

Using a two‐microelectrode voltage clamp technique, we investigated possible mechanisms underlying the impaired excitation–contraction coupling in skeletal muscle fibres of the mdx mouse, a model of the human disease Duchenne muscular dystrophy. We evaluated the role of the transverse tubular system (T‐system) by using the potentiometric indicator di‐8 ANEPPS, and that of the sarcoplasmic reticulum (SR) Ca2+ release by measuring Ca2+ transients with a low affinity indicator in the presence of high EGTA concentrations under voltage clamp conditions. We observed minimal differences in the T‐system structure and the T‐system electrical propagation was not different between normal and mdx mice. Whereas the maximum Ca2+ release elicited by voltage pulses was reduced by ∼67% in mdx fibres, in agreement with previous results obtained using AP stimulation, the voltage dependence of SR Ca2+ release was identical to that seen in normal fibres. Taken together, our data suggest that the intrinsic ability of the sarcoplasmic reticulum to release Ca2+ may be altered in the mdx mouse.
Transient outward K+ currents in rat dissociated subfornical organ neurones and angiotensin II effects
Authors: Ono Kentaro , Toyono Takashi , Honda Eiko , Inenaga Kiyotoshi
Published: August 2005

Although angiotensin II inhibits transient outward K+ currents (IAs) in subfornical organ neurones, there is no evidence concerning which Kv channels are involved. We investigated IA‐generating Kv channels in dissociated rat subfornical organ neurones, using molecular, electrophysiological and pharmacological techniques, and studied the effects of angiotensin II. Conventional RT‐PCR showed the presence of mRNAs for channels of the Kv3.4, Kv1.4 and Kv4 families, which are capable of generating IAs. Tetraethylammonium at 1 mm, which blocks Kv3 channel‐derived currents, and blood‐depressing substance‐I, a Kv3.4‐specific blocker, at 2 μm suppressed the IA‐like component of whole‐cell outward currents in some neurones. 4‐Aminopyridine at 5 mm inhibited IAs in the presence of tetraethylammonium at 1 mm. Cd2+ at 300 μm shifted the activation and inactivation curves of the 4‐aminopyridine‐sensitive and tetraethylammonium‐resistant IAs positively. The tetraethylammonium‐resistant IAs showed fast and slow components during the process of recovery from inactivation, but the slow component was not seen in all neurones. The time constant of the fast recovery component was less than 200 ms, while that of the slow recovery component was around 1 s. Using single‐cell RT‐PCR, mRNAs for Kv4.2 and Kv4.3L were detected frequently, but those for Kv1.4 and Kv3.4 were seen only rarely. Angiotensin II at 30 nm inhibited the fast recovery component of tetraethylammonium‐resistant IAs in many neurones. These results suggest that the fast recovery component of the tetraethylammonium‐resistant IA in subfornical organ neurones depends upon Kv4, and that it can be modulated by angiotensin II.
Movement‐related frequency modulation of beta oscillatory activity in the human subthalamic nucleus
Authors: Foffani G. , Bianchi A. M. , Baselli G. , Priori A.
Published: August 2005

Event‐related changes of brain electrical rhythms are typically analysed as amplitude modulations of local field potential (LFP) oscillations, like radio amplitude modulation broadcasting. In telecommunications, frequency modulation (FM) is less susceptible to interference than amplitude modulation (AM) and is therefore preferred for high‐fidelity transmissions. Here we hypothesized that LFP rhythms detected from deep brain stimulation (DBS) electrodes implanted in the subthalamic nucleus (STN) in patients with Parkinson's disease could represent movement‐related activity not only in AM but also in FM. By combining adaptive autoregressive identification with spectral power decomposition, we were able to show that FM of low‐beta (13–20 Hz) and high‐beta (20–35 Hz) rhythms significantly contributes to the involvement of the human STN in movement preparation, execution and recovery, and that the FM patterns are regulated by the dopamine levels in the system. Movement‐related FM of beta oscillatory activity in the human subthalamic nucleus therefore provides a novel informational domain for rhythm‐based pathophysiological models of cortico‐basal ganglia processing.
Hindlimb unweighting for 2 weeks alters physiological properties of rat hindlimb motoneurones
Authors: Cormery Bruno , Beaumont Eric , Csukly Kristina , Gardiner Phillip
Published: August 2005

We sought to determine whether decreased neuromuscular use in the form of hindlimb unweighting (HU) would affect the properties of innervating motoneurones. Hindlimb weight‐bearing was removed in rats for a period of 2 weeks via hindlimb suspension by the tail. Following this the electrophysiological properties of tibial motoneurones were recorded under anaesthesia in situ. After HU, motoneurones had significantly (P < 0.05) elevated rheobase currents, lower antidromic spike amplitudes, lower afterhyperpolarization (AHP) amplitudes, faster membrane time constants, lower cell capacitances, and depolarized spike thresholds. Frequency–current (f–I) relationships were shifted significantly to the right (i.e. more current required to obtain a given firing frequency), although there was no change in f–I slopes. ‘Slow’ motoneurones (AHP half‐decay times, > 20 ms) were unchanged in proportions in HU compared to weight‐bearing rats. Slow motoneurones had significantly lower minimum firing frequencies and minimum currents necessary for rhythmic firing than ‘fast’ motoneurones in weight‐bearing rats; these differences were lost in HU rats, where slow motoneurones resembled fast motoneurones in these properties. In a five‐compartment motoneurone model with ion conductances incorporated to resemble firing behaviour in vivo, most of the changes in passive and rhythmic firing properties could be reproduced by reducing sodium conductance by 25% and 15% in the initial segment and soma, respectively, or by increasing potassium conductance by 55% and 42%, respectively. This supports previous conclusions that changes in chronic neuromuscular activity, either an increase or decrease, may result in physiological adaptations in motoneurones due to chronic changes in ion conductances.
Measurement of nitric oxide release evoked by systemic hypoxia and adenosine from rat skeletal muscle in vivo
Authors: Ray Clare J. , Marshall Janice M.
Published: August 2005

It is accepted that NO plays a role in hypoxic vasodilatation in several tissues. For rat hindlimb muscle there is evidence that during systemic hypoxia endogenously released adenosine acts on endothelial A1 receptors to evoke dilatation in a NO‐dependent fashion, implying requirement for, or mediation by, NO. We tested in vivo whether systemic hypoxia and adenosine release NO from muscle. In anaesthetized rats, arterial blood pressure (ABP) and femoral blood flow (FBF) were recorded allowing computation of femoral vascular conductance (FVC). Blood samples taken from femoral artery and vein allowed electrochemical measurement of plasma [NO] after reduction of NO3− and NO2−. Systemic hypoxia and adenosine infusion for 5 min each, evoked an increase in FVC that was attenuated by the NO synthase (NOS) inhibitor l‐NAME (Group 1, n= 8) and adenosine A1 receptor antagonist 8‐cyclopentyl‐1,3‐dipropylxanthine (DPCPX, Group 2, n= 6). Concomitant systemic hypoxia and adenosine infusion evoked increases in venous–arterial [NO] difference ([NO]v‐a) from −1.4 ± 0.85 to 6.6 ± 1.6 and 2.3 ± 0.78 to 8.4 ± 1.8 nmol l−1, respectively (mean ±s.e.m), which were abolished by l‐NAME (−0.72 ± 0.90 to −0.87 ± 0.74 and 0.72 ± 0.85 to −0.97 ± 1.1 nmol l−1, respectively). DPCPX also abolished the hypoxia‐evoked increase in [NO]v‐a (control −4.2 ± 1.8 to 12.5 ± 3.7 nmol l−1, with DPCPX −0.63 ± 2.6 to 3.3 ± 2.9 nmol l−1) and decreased the adenosine‐evoked increase in [NO]v‐a (control 1.1 ± 1.5 to 24 ± 14, with DPCPX −0.43 ± 2.9 to 12 ± 5.9 nmol l−1). These results allow the novel conclusion that the muscle vasodilatation of systemic hypoxia is partly mediated by adenosine acting at endothelial A1 receptors to stimulate synthesis and release of NO, which then induces dilatation.
Dual Ca2+ modulation of glycinergic synaptic currents in rodent hypoglossal motoneurones
Authors: Mukhtarov Marat , Ragozzino Davide , Bregestovski Piotr
Published: August 2005

Glycinergic synapses are implicated in the coordination of reflex responses, sensory signal processing and pain sensation. Their activity is pre‐ and postsynaptically regulated, although mechanisms are poorly understood. Using patch‐clamp recording and Ca2+ imaging in hypoglossal motoneurones from rat and mouse brainstem slices, we address here the role of cytoplasmic Ca2+ (Cai) in glycinergic synapse modulation. Ca2+ influx through voltage‐gated or NMDA receptor channels caused powerful transient inhibition of glycinergic IPSCs. This effect was accompanied by an increase in both the failure rate and paired‐pulse ratio, as well as a decrease in the frequency of mIPSCs, suggesting a presynaptic mechanism of depression. Inhibition was reduced by the cannabinoid receptor antagonist SR141716A and occluded by the agonist WIN55,212‐2, indicating involvement of endocannabinoid retrograde signalling. Conversely, in the presence of SR141716A, glycinergic IPSCs were potentiated postsynaptically by glutamate or NMDA, displaying a Ca2+‐dependent increase in amplitude and decay prolongation. Both presynaptic inhibition and postsynaptic potentiation were completely prevented by strong Cai buffering (20 mm BAPTA). Our findings demonstrate two independent mechanisms by which Ca2+ modulates glycinergic synaptic transmission: (i) presynaptic inhibition of glycine release and (ii) postsynaptic potentiation of GlyR‐mediated responses. This dual Ca2+‐induced regulation might be important for feedback control of neurotransmission in a variety of glycinergic networks in mammalian nervous systems.
Neurokinin‐1 receptor desensitization to consecutive microdialysis infusions of substance P in human skin
Authors: Wong Brett J. , Tublitz Nathan J. , Minson Christopher T.
Published: August 2005

The neuropeptide substance P is known to be localized in nerve terminals in human skin and substance P‐induced vasodilatation is believed to be partially dependent on nitric oxide (NO) and H1 histamine receptor activation. Unlike other neuropeptides investigated in human skin, substance P‐induced vasodilatation has been shown to decline during continuous infusion, possibly suggestive of an internalization of neurokinin‐1 (NK1) receptors, which are highly specific to substance P. However, questions remain regarding these mechanisms in human skin. Fifteen subjects participated in this series of studies designed to investigate the effect of consecutive infusions and possible mechanisms of substance P‐induced vasodilatation in human skin. Two concentrations of substance P (10 μmand 20 μm) were tested via intradermal microdialysis in two groups of subjects. Site 1 served as a control and received substance P only. Site 2 received substance P combined with 10 mm l‐NAME to inhibit NO synthase. Site 3 received substance P combined with 500 μmpyrilamine, an H1 receptor antagonist. Site 4 received substance P combined with 10 mm l‐NAME plus 500 μmpyrilamine. Red blood cell (RBC) flux was measured via laser‐Doppler flowmetry to provide an index of skin blood flow. Cutaneous vascular conductance was calculated as RBC flux/mean arterial pressure and was normalized to maximal vasodilatation via 28 mmsodium nitroprusside. Substance P was perfused through each microdialysis fibre at a rate of 4 μl min−1for 15 min. The subsequent increase in skin blood flow was allowed to return to baseline (∼45–60 min) and a stable 5 min plateau was used as a new baseline (post‐infusion baseline). A second dose of substance P was then delivered to the skin and skin blood flow was monitored for 45–60 min. Substance P produced a dose‐dependent increase in skin blood flow with the concentrations of substancePtested, which was significantly attenuated in the presence ofl‐NAME and the combination ofl‐NAME plus pyrilamine. However, substance P‐induced vasodilatation was unaffected in the presence of pyrilamine. There was no significant difference between thel‐NAME‐only sites and thel‐NAME plus pyrilamine sites. Importantly, the second dose of substance P did not produce a significant increase in skin blood flow compared to the initial baseline or the post‐infusion baseline. These data suggest substance P‐induced vasodilatation delivered via microdialysis contains an NO component but does not contain an H1 receptor activation component at the doses tested. Additionally, these data provide evidence for NK1receptor desensitization as there was no observable increase in skin blood flow following a second administration of substance P. This may provide a useful model for studying the role of substance P in the control of skin blood flow in humans.
Constraint-Based Computer-Aided Design
Authors: Hoffmann Christoph M.
Published: August 2005

Computer-aided design (CAD) systems have become parametric, basing shape design on constraints and design feature operations. We review the development of constraint-based parametric CAD, explaining some of the foundational issues as well as giving an outlook on possible future directions of development.
A Comparative Study Of Tolerance Analysis Methods
Authors: Shen Zhengshu , Ameta Gaurav , Shah Jami J. , Davidson Joseph K.
Published: August 2005

This paper reviews four major methods for tolerance analysis and compares them. The methods discussed are: (1) one-dimensional tolerance charts; (2) parametric tolerance analysis, especially parametric analysis based on the Monte Carlo simulation; (3) vector loop (or kinematic) based tolerance analysis; and (4) ASU Tolerance-Map® (T-Map®) (Patent pending; nonprovisional patent application number: 09/507, 542 (2002)) based tolerance analysis. Tolerance charts deal with worst-case tolerance analysis in one direction at a time and ignore possible contributions from the other directions. Manual charting is tedious and error prone, hence, attempts have been made for automation. The parametric approach to tolerance analysis is based on parametric constraint solving; its inherent drawback is that the accuracy of the simulation results are dependent on the user-defined modeling scheme, and its inability to incorporate all Y14.5 rules. The vector loop method uses kinematic joints to model assembly constraints. It is also not fully consistent with Y14.5 standard. The ASU T-Map® based tolerance analysis method can model geometric tolerances and their interaction in truly three-dimensional context. It is completely consistent with Y14.5 standard but its use by designers may be quite challenging. The T-Map® based tolerance analysis method is still under development. Despite the shortcomings of each of these tolerance analysis methods, each may be used to provide reasonable results under certain circumstances. Through a comprehensive comparison of these methods, this paper will offer some recommendations for selecting the best method to use for a given tolerance accumulation problem.
A Survey of Structural Optimization in Mechanical Product Development
Authors: Saitou Kazuhiro , Izui Kazuhiro , Nishiwaki Shinji , Papalambros Panos
Published: August 2005

The widespread availability of affordable high-performance personal computers and commercial software has prompted the integration of structural analyses with numerical optimization, reducing the need for design iterations by human designers. Despite its acceptance as a design tool, however, structural optimization seems yet to gain mainstream popularity in industry. To remedy this situation, this paper reviews past literatures on structural optimization with emphasis on their relation to mechanical product development, and discusses open research issues that would further enhance the industry acceptance of structural optimization. The past literatures are categorized based on their major research focuses: geometry parameterization, approximation methods, optimization algorithms, and the integration with nonstructural issues. Open problems in each category and anticipated future trends briefly are discussed.
Modeling and Simulation of Multiphysics Systems
Authors: Michopoulos John G. , Farhat Charbel , Fish Jacob
Published: August 2005

A survey on the evolution of modeling and simulation (M&S) technologies related to multiphysics systems is presented. The concept of a context space for M&S is defined in terms of coexisting fields, domains of interaction, length scales, and computational technologies. Past and present efforts comprising this context space are described as well as their relationship to product development [i.e., efforts of ASME’s Computer and Information in Engineering (CIE) division]. A retrospective of general procedures for developing multifield and multidomain formulations is elucidated for the case fluid-structure interaction pertaining to linear and nonlinear aeroelasticity and aerothermoelasticity as they mostly relate to aerospace applications. Multiscale methodologies and computational technologies associated with M&S generation follow. The evolution of computational and information technologies are also described as they relate to multiphysics M&S. Future potential trends associated with all of these areas conclude this work.
Streamlining Product Lifecycle Processes: A Survey of Product Lifecycle Management Implementations, Directions, and Challenges
Authors: Rangan Ravi M. , Rohde Steve M. , Peak Russell , Chadha Bipin , Bliznakov Plamen
Published: August 2005

The past three decades have seen phenomenal growth in investments in the area of product lifecycle management (PLM) as companies exploit opportunities in streamlining product lifecycle processes, and fully harnessing their data assets. These processes span all product lifecycle phases from requirements definition, systems design/ analysis, and simulation, detailed design, manufacturing planning, production planning, quality management, customer support, in-service management, and end-of-life recycling. Initiatives ranging from process re-engineering, enterprise-level change management, standardization, globalization and the like have moved PLM processes to mission-critical enterprise systems. Product data representations that encapsulate semantics to support product data exchange and PLM collaboration processes have driven several standards organizations, vendor product development efforts, real-world PLM implementations, and research initiatives. However, the process and deployment dimensions have attracted little attention: The need to optimize organization processes rather than individual benefits poses challenging “culture change management” issues and have derailed many enterprise-scale PLM efforts. Drawn from the authors’ field experiences as PLM system integrators, business process consultants, corporate executives, vendors, and academicians, this paper explores the broad scope of PLM, with an added focus on the implementation and deployment of PLM beyond the development of technology. We review the historical evolution of engineering information management/PLM systems and processes, characterize PLM implementations and solution contexts, and discuss case studies from multiple industries. We conclude with a discussion of research issues motivated by improving PLM adoption in industry.
Product Information Exchange: Practices and Standards
Authors: Fenves Steven J. , Sriram Ram D. , Subrahmanian Eswaran , Rachuri Sudarsan
Published: August 2005

The paper discusses the evolution of product information exchange from point-to-point exchange of geometry between computer-aided design tools through today’s suite of tools and processes of computer-aided product development (CAPD) to the future fully integrated computer-aided product realization (CAPR) process. The categories of processes and the layers of information exchange are reviewed. The current practice in product information exchange, the relevant information exchange standards, and near-future plans for improvements are presented. The major recent demands on more comprehensive product information exchange are discussed in terms of the exchange of nongeometric information and support of feature-based design, knowledge-based engineering, and management of product variety. Two conceptual frameworks for the support of CAPD and CAPR, representative of current research, are briefly sketched. Finally, a conceptual model of product information exchange is presented so as to define the range of implementation and standardization paths that may be taken in the future.
The CAD/CAM Interface: A 25-Year Retrospective
Authors: Corney J. , Hayes C. , Sundararajan V. , Wright P.
Published: August 2005

The vision of fully automated manufacturing processes was conceived when computers were first used to control industrial equipment. But realizing this goal has not been easy; the difficulties of generating manufacturing information directly from computer aided design (CAD) data continued to challenge researchers for over 25 years. Although the extraction of coordinate geometry has always been straightforward, identifying the semantic structures (i.e., features) needed for reasoning about a component’s function and manufacturability has proved much more difficult. Consequently the programming of computer controlled manufacturing processes such as milling, cutting, turning and even the various lamination systems (e.g., SLA, SLS) has remained largely computer aided rather than entirely automated. This paper summarizes generic difficulties inherent in the development of feature based CAD/CAM (computer aided manufacturing) interfaces and presents two alternative perspectives on developments in manufacturing integration research that have occurred over the last 25 years. The first perspective presents developments in terms of technology drivers including progress in computational algorithms, enhanced design environments and faster computers. The second perspective describes challenges that arise in specific manufacturing applications including multiaxis machining, laminates, and sheet metal parts. The paper concludes by identifying possible directions for future research in this area.
A Mechanical Model for Demonstrating Fermat's Principle
Authors: Moore W. Cullen
Published: August 2005

An advantage of the general principle approach to physics as contrasted to the particularized formulation of physical relationships is exemplified by the solution of a research problem in ionospheric radio propagation. The generalized approach resulted in the construction of a mechanical analog computer which can be used to demonstrate Fermat's principle. This paper outlines briefly the theory of least action, shows how it can be applied to mechanical systems, electrical circuits, and ray optics to obtain the more familiar laws describing their behavior, and describes the essential similarity between an optical system and its mechanical analog. The mechanical demonstrator can be assembled from common laboratory equipment for classroom demonstration, or it can be carefully constructed for use in computing tables of radio propagation times for ray paths bounded by the earth and ionospheric layers.
A Laboratory Exercise in Nuclear Emulsion Technique
Authors: Peck R. A. , Stelson Paul
Published: August 2005

A laboratory exercise in photographic emulsion track measurement is described, adaptable to any student level from the sophomore to the first-year graduate. The prime objective is student observation of emulsion tracks, and the unique pedagogical advantages of this recording medium are considered. Details of procedure and analysis of data are discussed.
Analysis of an R-C Oscillator
Authors: Howey Joseph H.
Published: August 2005

The equations for an R-C oscillator are derived completely from fundamental relationships without the use of alternating current concepts and without the use of complex numbers. Analyzed in this way, the R-C oscillator constitutes a good subject for an experiment dealing with the equation for simple harmonic motion. Theoretical expressions obtained for the frequency and for the damping coefficient can be verified by experiment, and either positive or negative damping may be had. With commonly available apparatus, the period may be made several seconds long. The oscillations and the growth or decay of amplitude with time can thus be observed directly with a milliammeter biased to read zero at its center. Familiarity with a simple two-stage triode amplifier constitutes the needed background in electronics for this experiment.
The Classical Motion of a Rigid Charged Body in a Magnetic Field
Authors: Goldstein Herbert
Published: August 2005

A frequently used classical analog to the quantum precession of a magnetic moment in a magnetic field is the motion in a uniform static magnetic field of a symmetrical rigid body charged so that the ratio of charge to mass density is uniform. In general, the figure axis of such a magnetic top both precesses and nutates, and the mechanism producing the nutation is qualitatively different from that responsible for the nutation of the familiar gravitational top. Unless the body is spherical the angular momentum vector also nutates in the course of the precession, a phenomenon caused by the deviation of the torque on the body from the customary, but here incorrect, expression M×B. The uniform precession frequency of the magnetic top is not the Larmor frequency but involves in addition terms depending on higher powers of the magnetic field, a correction which corresponds to the quadratic Zeeman effect.
On Order Parameters
Authors: Klein Martin J.
Published: August 2005

The problem of describing the state of order in a binary alloy is considered. A set of order parameters is defined in the following way: pi is the probability that if a given site is occupied by a B atom then a site which is its ith neighbor is occupied by an A atom. The relationships of this set to the parameters used by other authors are discussed.
Elementary Laboratory for Premedical Students
Authors: Mohler Nora M. , Lorentz Lilly , Bunce Elizabeth T.
Published: August 2005

A brief description is given of supplementary experiments for premedical students, with a bibliography of useful references. Included are: the back as a lever, with calculation of the force on the fifth lumbar vertebra; charting of temperature and pulse rates for a considerable period; a metabolism test with a calculation of the rate of energy production in the body: individual audiometer tests following a lecture on hearing; the physiology of the eye; formation of images on the retina; the relation between acuity and illumination; color and theories of color vision; a discussion of the problem of nerve conduction; the use of a Wheatstone bridge as a lie detector; electrocardiographs. It seems successful as judged by the caliber of the students' work and by their interest.
Causality, Relativity, and Language
Authors: Fein Elihu
Published: August 2005

The development of modern physics requires that verbal interpretations given to the symbols used in mathematical analysis be closely examined to determine whether such verbal interpretations are meaningful or even possible. The concept “causality” is studied. Considerations suggested by relativity theory indicate that this concept can have only a local meaning and that, in particular, two observers in different parts of the universe could not communicate adequately with each other if they employed the concept of causality in their statements of physical phenomena. It is requisite that the scientist give up his insistence on verbal translations of abstract symbols in order that he be able to make more general and profound insights in his analytical reasoning.
The Employment of Physicists by the Department of the Army
Authors: White Marsh W.
Published: August 2005

Physicists are being employed in installations of the U. S. Army in increasing numbers. Although research and development activities are their major function, many are engaged in administration, technical writing, liaison duties, and staff work. In many respects the work of physicists in Army laboratories is similar to that in typical university centers. Salary scales are generally higher than those for comparable academic positions but below those often paid in industry. Many positions filled by physicists are classified by titles not clearly identified with physics. Physics training as a background field is a requisite by many Army scientists who are not professional physicists. The Army facilities for experimental work in physics are excellent. Most Army research and development centers are administered by the technical services. Army policy provides that scientific employees be given opportunity for considerable professional development through publication of technical papers, attendance at scientific meetings, and further study.
Atwood's Machine and the Teaching of Newton's Second Law
Authors: Kofsky Irving L.
Published: August 2005

The use of Atwood's machine in illustrating the principles of the application of Newton's second law to a simple physical system, whose connected parts have both rotational and translational motion, is shown. A diagram which shows the forces acting on all the component masses is drawn, and this picture facilitates the setting-up of the appropriate F = ma and τ = Iα equations. The moment of inertia of the pulley, the friction in its bearings, and the mass of the string are included in the accelerating system in a natural way. The observed acceleration of the hanging masses can be compared with that computed by this method.
Moment of Inertia Experiment
Authors: Erickson Willard L.
Published: August 2005

This paper describes a laboratory experiment for determining moment of inertia in which the emphasis is on (1) a relatively high degree of accuracy, (2) useful application of several of the important principles of mechanics, and (3) improved instrumentation to attain the desired accuracy and still give time in the laboratory period for the student to explore the details and implications of the experiment.
John Wesley Hornbeck: Recipient of the 1950 Oersted Medal for Notable Contributions to the Teaching of Physics
Authors: Buchta J. W.
Published: August 2005

The American Association of Physics Teachers has made to Professor John Wesley Hornbeck, lately Professor of Physics at Kalamazoo College, the fifteenth of its annual awards for notable contributions to the teaching of physics. Following an address of recommendation by Professor J. W. Buchta, Chairman of the Committee on Awards, the presentation was made by Professor Duane E. Roller, President of the Association, in a ceremony held in McMillan Hall, Columbia University, on February 2, 1951, during the twentieth annual meeting.
The Fundamental Problems of Experimental Physics
Authors: Hough James
Published: August 2005

An elementary treatment of the nature of an experiment is given in order to demonstrate the various factors which must be considered in planning an experiment. Particular attention has been paid to the factors on which the accuracy of the final result depends; and it has been found desirable to introduce two new quantities, the reading and experimental limits, which give a measure of the maximum accuracy of a measurement and an experiment, respectively, obtainable with the particular apparatus.
Laboratory Performance Tests at the University of Minnesota
Authors: Wall C. N. , Kruglak H. , Trainor L. E. H.
Published: August 2005

The frequent discrepancies between paper-and-pencil grades of science students and their performance in the laboratory point to the need for behavior-sampling tests: Experience with performance tests at the University of Minnesota has shown that their use (1) increases the spread of grades, (2) results in greater motivation, and (3) facilitates the measurement of instructional outcomes. Typical tests in mechanics, electricity, sound, and optics are reproduced and the important phases of the testing program are described. The detailed statistical analysis of the mechanics performance test points to the need of additional experimentation in this field.
Statistical Fluctuation in Radioactive Phenomena
Authors: Grundl J. A. , Karioris F. G. , Barkow A. G.
Published: August 2005

An experiment applicable to an intermediate laboratory course in modern physics is presented. The method is fundamentally that used in 1910 by Rutherford and Geiger, with a G-M scaler and tape recorder replacing the scintillation technique. The experiment establishes the random nature of radioactive decay and introduces the student to the concept of statistical fluctuation.