bluuebunny/crossref_metadata_2025 huggingface dataset:
Transient Up-regulation of Spinal Cyclooxygenase-2 and Neuronal Nitric Oxide Synthase following Surgical Inflammation
Authors: Dolan Sharron , Kelly James G. , Huan Marie , Nolan Andrea M.
Published: February 2004

Background

Surgery induces pain and hyperalgesia postoperatively. The products of cyclooxygenases and nitric oxide synthase (NOS) have been implicated in the development of inflammatory pain and hyperalgesia experimentally, and the use of drugs clinically that modify cyclooxygenase activity has been advocated in the management of perioperative pain. However, regulation of these enzymes following surgery has not been studied.

Methods

Adult female sheep (n = 12) undergoing a midline laparotomy for collection of ova were used in this study. Lumbar and cervical spinal cord tissue was collected from animals euthanized 1 day and 6 or 7 days after surgery and processed for cyclooxygenase (cyclooxygenase-1 and cyclooxygenase-2), neuronal NOS mRNA expression using reverse-transcription polymerase chain reaction and hybridization. Tissues were also processed for NADPH-diaphorase staining and cyclooxygenase-1 and cyclooxygenase-2 protein expression by immunohistochemistry and Western blotting.

Results

No alteration in cyclooxygenase-1 or cyclooxygenase-2 mRNA or protein concentrations were detected in spinal cord by reverse-transcription polymerase chain reaction and Western blotting, respectively, at 1 day or 6 or 7 days after surgery. However, using techniques that localize mRNA and protein expression ( hybridization and immunohistochemistry, respectively), increases in cyclooxygenase-2 were identified in lamina V dorsal horn neurons in lumbar spinal cord 1 day after surgery. A significant increase in neuronal NOS mRNA was observed in lumbar spinal cord 1 day after surgery, localized to laminae I-II and lamina V neurons, which returned to baseline concentrations by 6 to 7 days. NADPH-diaphorase staining was significantly increased in laminae I-II in lumbar spinal cord 1 day after surgery but not after 6 to 7 days.

Conclusions

Spinal cyclooxygenase and neuronal NOS pathways are differentially altered following surgical inflammation. The early and transient nature of these changes suggests that these enzymes are implicated in postoperative pain and hypersensitivity.
On the Mechanism by Which Epinephrine Potentiates Lidocaine's Peripheral Nerve Block
Authors: Sinnott Catherine J. , Cogswell Lawrence P. , Johnson Anthony , Strichartz Gary R.
Published: February 2004

Background

Adding epinephrine to lidocaine solutions for peripheral nerve block potentiates and prolongs the action, but by incompletely understood mechanisms. In an effort to discriminate the pharmacokinetic from the pharmacodynamic effects of epinephrine, the authors measured the lidocaine content of peripheral nerve over the course of block produced by 0.5% lidocaine, with and without epinephrine, and correlated it with the degree of analgesia.

Methods

Percutaneous sciatic nerve blocks were performed in 18 groups of rats (10 in each) with 0.1 ml of either 0.5% lidocaine or 0.5% lidocaine with epinephrine (1:100,000). Over the full course of nerve block, the authors regularly measured analgesia to toe pinch and then rapidly removed nerves to assay intraneural lidocaine content at 2-120 min after injection.

Results

The kinetics of lidocaine's clearance from nerve was composed of a fast-decaying transient superimposed on a very slowly decaying component. The effect of epinephrine on the intraneural lidocaine content was to increase the amount of lidocaine in the slow-decaying component by threefold to fourfold, although the total neural content was not altered by epinephrine for the first 10 min after injection. Epinephrine prolonged blockade by almost fourfold and enhanced the intensity of peak analgesia, as well as the fraction of rats with complete block, almost throughout the 2-120-min period of behavioral observation.

Conclusions

Adding epinephrine to lidocaine solutions increases the intensity and duration of sciatic nerve block in the rat. The early increase in intensity is not matched with an increase in intraneural lidocaine content at these early times, although the prolonged duration of block by epinephrine appears to correspond to an enlarged lidocaine content in nerve at later times, as if a very slowly emptying "effector compartment" received a larger share of the dose. The increase in early analgesia without increased lidocaine content may be explained by a pharmacodynamic action of epinephrine that transiently enhances lidocaine's potency, but also by a pharmacokinetic effect that alters the distribution of the same net content of lidocaine within the nerve.
Modulation of Peripheral Endogenous Opioid Analgesia by Central Afferent Blockade
Authors: Schmitt Thomas K. , Mousa Shaaban A. , Brack Alexander , Schmidt Diego K. , Rittner Heike L. , Welte Martin , Schäfer Michael , Stein Christoph
Published: February 2004

Background

Peripheral tissue injury causes a migration of opioid peptide-containing immune cells to the inflamed site. The subsequent release and action of these peptides on opioid receptors localized on peripheral sensory nerve terminals causes endogenous analgesia. The spinal application of opioid drugs blocks the transmission of nociceptive information from peripheral injury. This study investigates the influence of exogenous spinal opioid analgesia on peripheral endogenous opioid analgesia.

Methods

Six and forty-eight hours after initiation of continuous intrathecal morphine infusion and administration of Freund's complete adjuvant into the hind paw of rats, antinociceptive and antiinflammatory effects were measured by paw pressure threshold, paw volume, and paw temperature, respectively. Inflammation and quantity of opioid-containing cells were evaluated by immunocytochemistry and flow cytometry. Cold water swim stress-induced endogenous analgesia was examined 24 h after discontinuation of intrathecal morphine administration.

Results

Intrathecal morphine (10 micro g/h) resulted in a significant and stable increase of paw pressure threshold ( P< 0.05) without changing inflammation, as evaluated by paw volume, paw temperature, and flow cytometry ( P> 0.05). At 48 but not at 6 h after Freund's complete adjuvant, the number of beta-endorphin-containing cells and cold water swim-induced antinociception were significantly reduced in intrathecal morphine-treated rats compared with those treated with intrathecal vehicle ( P< 0.05).

Conclusions

These findings suggest an interplay of central and peripheral mechanisms of pain control. An effective central inhibition of pain apparently signals a reduced need for recruitment of opioid-containing immune cells to injured sites.
Intrathecal Lidocaine Reverses Tactile Allodynia Caused by Nerve Injuries and Potentiates the Antiallodynic Effect of the COX Inhibitor Ketorolac
Authors: Ma Weiya , Du Wei , Eisenach James C.
Published: February 2004

Background

Systemic lidocaine and other local anesthetics reduce hypersensitivity states induced by both acute inflammation and peripheral nerve injury in animals and produce analgesia in some patients with chronic pain. The mechanisms underlying the antiallodynic effect of systemic lidocaine are unclear, although most focus is on peripheral mechanisms. Central mechanisms, particularly at the spinal dorsal horn level, are less known. In this study, the authors aimed to determine whether intrathecal lidocaine has an antiallodynic effect on established mechanical allodynia in two well-characterized neuropathic pain rat models: partial sciatic nerve ligation (PSNL) and spinal nerve ligation (SNL).

Methods

Lidocaine (100-300 micro g) was intrathecally injected in PSNL and SNL rats. The withdrawal threshold of both hind paws in response to mechanical stimulation was measured using a series of calibrated von Frey filaments.

Results

This single injection reduced ongoing tactile allodynia in PSNL and SNL rats. The antiallodynic effect of intrathecal lidocaine lasted longer in PSNL (> 3 days) than in SNL rats (< 3 days). Intraperitoneal lidocaine (300 micro g) had no effect on tactile allodynia in PSNL rats. In SNL rats, prior intrathecal lidocaine (200 and 300 micro g) potentiated the antiallodynic effect of intrathecal ketorolac, a nonselective cyclooxygenase inhibitor. Intrathecal ketorolac alone had no antiallodynic effect on SNL rats. However, prior intrathecal lidocaine (100 micro g) failed to potentiate the antiallodynic effect of intrathecal ketorolac.

Conclusion

The authors' data suggest that intrathecal lidocaine possibly suppressed the hyperexcitability of the dorsal horn neurons and likely interacted with eicosanoid systems in the spinal dorsal horn.
Fentanyl Decreases Ca2+Currents in a Population of Capsaicin-responsive Sensory Neurons
Authors: McDowell Thomas S.
Published: February 2004

Background

Neuraxial opioids produce analgesia in part by decreasing excitatory neurotransmitter release from primary nociceptive neurons, an effect that may be due to inhibition of presynaptic voltage-activated Ca2+ channels. The purpose of this study was to determine whether opioids decrease Ca2+ currents (I Ca ) in primary nociceptive neurons, identified by their response to the algogenic agent capsaicin.

Methods

I was recorded from acutely isolated rat dorsal root ganglion neurons using the whole cell patch clamp technique before, during, and after application of the micro -opioid agonist fentanyl (0.01-1 micro m). Capsaicin was applied to each cell at the end of the experiment.

Results

Fentanyl reduced I Ca in a greater proportion of capsaicin-responsive cells (62 of 106, 58%) than capsaicin-unresponsive cells (2 of 15, 13%; P < 0.05). Among capsaicin-responsive cells, the decrease in I Ca was 38 +/- 3% (n = 36, 1 micro m) in fentanyl-sensitive cells just 7 +/- 1% (n = 15, 1 micro m; P < 0.05) in fentanyl-insensitive cells. Among capsaicin-responsive cells, I Ca inactivated more rapidly in fentanyl-sensitive cells (tau, 52 +/- 4 ms, n = 22) than in fentanyl-insensitive cells (93 +/- 14 ms, n = 24; P < 0.05). This was not due to differences in the types of Ca2+ channels expressed as the magnitudes of omega-conotoxin GVIA-sensitive (N-type), nifedipine-sensitive (L-type), and GVIA/nifedipine-resistant (primarily P-/Q-type) components of I Ca were similar.

Conclusions

The results show that opioid-sensitive Ca2+ channels are expressed by very few capsaicin-unresponsive neurons but by more than half of capsaicin-responsive neurons. The identity of the remaining capsaicin-responsive (and therefore presumed nociceptive) neurons that express opioid-insensitive Ca2+ channels is unknown but may represent a potential target of future non-opioid-based therapies for acute pain.
Aβ-Induced Vascular Oxidative Stress and Attenuation of Functional Hyperemia in Mouse Somatosensory Cortex
Authors: Park Laibaik , Anrather Josef , Forster Colleen , Kazama Ken , Carlson George A , Iadecola Costantino
Published: February 2004

We investigated the role of vascular oxidative stress in the mechanisms of the impairment in cerebrovascular regulation produced by the amyloid-β peptide (Aβ). In particular, we sought to provide evidence of vascular oxidative stress in mice overexpressing the amyloid precursor protein (APP) and to determine whether the Aβ-induced attenuation in functional hyperemia is mediated by free radical overproduction. Oxidative/nitrosative stress was assessed by 3-nitrotyrosine immunoreactivity, while free radical production was determined in cerebral microvessels by hydroethidine microfluorography. To study functional hyperemia the somatosensory cortex was activated by whisker stimulation while local blood flow was monitored by laser-Doppler flowmetry. It was found that APP mice show signs of oxidative/nitrosative stress in pial and intracerebral blood vessels well before they develop oxidative stress in neurons and glia or amyloid plaques. Treatment of cerebral microvessels isolated from wild-type mice with Aβ (1 μM) increased free radical production as assessed by the hydroethidine technique. The Aβ-induced attenuation of the increase in somatosensory cortex blood flow produced by whisker stimulation was prevented by treatment with the free radical scavengers MnTBAP or tiron. These data provide evidence that in APP mice vascular oxidative stress precedes the development of parenchymal oxidative stress, and that Aβ-produced vascular reactive oxygen species are involved in the attendant attenuation in functional hyperemia. Thus, vascular oxidative stress is an early event in the course of the brain dysfunction produced by APP overexpression and Aβ, and, as such, could be the target of early therapeutic interventions based on antioxidants.
Retinal Discoloration Test
Authors: Joshi Shailendra , Wang Mei , Hartl Roger
Published: February 2004

There are considerable variations in the size and the origin of internal carotid arteries (ICAs) of New Zealand white rabbits. A simple test that could correctly identify the ICA could facilitate intracarotid delivery of drugs and embolic material for research in these animals. Five conventional methods for identifying the ICA proved inferior to a novel retinal discoloration test (RDT). A positive RDT implies a change in color of the retinal reflex after injection of 0.2 mL of indigo-carmine blue (ICB). We conclude that RDT is a useful test for correctly identifying and isolating the ICA in this animal species.
Interstitial pO2 in Ischemic Penumbra and Core are Differentially Affected following Transient Focal Cerebral Ischemia in Rats
Authors: Liu Shimin , Shi Honglian , Liu Wenlan , Furuichi Takamitsu , Timmins Graham S , Liu Ke Jian
Published: February 2004

Stroke causes heterogeneous changes in tissue oxygenation, with a region of decreased blood flow, the penumbra, surrounding a severely damaged ischemic core. Treatment of acute ischemic stroke aims to save this penumbra before its irreversible damage by continued ischemia. However, effective treatment remains elusive due to incomplete understanding of processes leading to penumbral death. While oxygenation is central in ischemic neuronal death, it is unclear exactly what actual changes occur in interstitial oxygen tension (pO2) in ischemic regions during stroke, particularly the penumbra. Using the unique capability of in vivo electron paramagnetic resonance (EPR) oximetry to measure localized interstitial pO2, we measured both absolute values, and temporal changes of pO2 in ischemic penumbra and core during ischemia and reperfusion in a rat model. Ischemia rapidly decreased interstitial pO2 to 32% ± 7.6% and 4% ± 0.6% of pre-ischemic values in penumbra and core, respectively 1 hour after ischemia. Importantly, whilst reperfusion restored core pO2 close to its pre-ischemic value, penumbral pO2 only partially recovered. Hyperoxic treatment significantly increased penumbral pO2 during ischemia, but not in the core, and also increased penumbral pO2 during reperfusion. These divergent, important changes in pO2 in penumbra and core were explained by combined differences in cellular oxygen consumption rates and microcirculation conditions. We therefore demonstrate that interstitial pO2 in penumbra and core is differentially affected during ischemia and reperfusion, providing new insights to the pathophysiology of stroke. The results support normobaric hyperoxia as a potential early intervention to save penumbral tissue in acute ischemic stroke.
Effects of Reperfusion on ADC and CBF Pixel-by-Pixel Dynamics in Stroke: Characterizing Tissue Fates using Quantitative Diffusion and Perfusion Imaging
Authors: Shen Qiang , Fisher Marc , Sotak Christopher H , Duong Timothy Q
Published: February 2004

The effects of reperfusion on the spatiotemporal dynamics of transient (60 minutes) focal ischemic brain injury in rats were evaluated on a pixel-by-pixel basis using quantitative cerebral blood flow (CBF) and apparent diffusion coefficient (ADC) measurements every 30 minutes for 3 hours and compared to post-mortem histology at 24 hours. Four biologically relevant clusters were classified based on ADC (0.53 ± 0.02 × 10−3mm2/s, SD) and CBF (0.30 ± 0.09ml/g/min) viability thresholds, namely: (1) the “normal” cluster with ADC and CBF > thresholds; (2) the “mismatch” cluster with ADC > threshold but CBF < threshold; (3) the “core” cluster with ADC and CBF < thresholds; and (4) “non-nourishing reperfusion zone” where ADC < threshold but CBF > threshold. The spatio-temporal progression of tissue volumes, ADC and CBF of each cluster were evaluated. Pixels of each cluster on the CBF-ADC space were mapped onto the image space. Following reperfusion, 28% of the “core” pixels and 90% of the “mismatch” (defined at 60 minutes) pixels were salvaged at 180 minutes, which correlated with histology. The ADC and CBF of subsequently salvaged tissues were significantly higher than those became infarcted. Salvaging “core” pixels indicated that reduced ADC was not synonymous with irreversible injury; duration of exposure and severity of reduced ADC and CBF were likely critical. Projection profiles showed a bimodal ADC, but uni-modal CBF, distributions. The ADC bimodal minima, obtained without histological correlation, were similar to the histology-derived ADC and CBF viability thresholds, and could have potential clinical applications. This study demonstrated a simple but powerful approach to evaluate, on a pixel-by-pixel basis, the spatio-temporal evolution of ischemic brain injury, and a potential for statistical prediction of tissue fate.
Quantification of Cerebral A1 Adenosine Receptors in Humans using [18F]CPFPX and PET
Authors: Meyer Philipp T , Bier Dirk , Holschbach Marcus H , Boy Christian , Olsson Ray A , Coenen Heinz H , Zilles Karl , Bauer Andreas
Published: February 2004

Adenosine is an important neuromodulator. Basic cerebral effects of adenosine are exerted by the A1 adenosine receptor (A1AR), which is accessible in vivo by the novel ligand [18F]8-cyclopentyl-3-(3-fluoropropyl)-1-propylxanthine ([18F]CPFPX) and positron emission tomography (PET). The present study investigates the applicability of kinetic models to describe the cerebral kinetics of [18F]CPFPX in order to quantify A1AR density in vivo. Six healthy volunteers underwent dynamic PET scanning and arterial blood sampling after bolus injection of [18F]CPFPX. For quantitative analysis, a standard two-tissue compartment model (2TCM) was compared with a one-tissue compartment model (1TCM) and Logan's graphical analysis (GA). The 2TCM described the cerebral kinetics of [18F]CPFPX significantly better than the 1TCM (in all regions and subjects examined). The estimated values of the regional total distribution volumes ( DVt) correlated strongly between the 2TCM and GA (linear regression r2 = 0.99, slope: 1.007). The DVt correlation between the 2TCM and the 1TCM was comparably high, but there was a significant bias towards lower DVt estimates given by the 1TCM (r2: 0.99, slope: 0.929). It is concluded that a 2TCM satisfactorily accounts for the cerebral kinetics of [18F]CPFPX. GA represents an attractive alternative method of analysis.
Differential Effects of 17β-Estradiol upon Stroke Damage in Stroke Prone and Normotensive Rats
Authors: Carswell Hilary V , Bingham Deborah , Wallace Kirsty , Nilsen M , Graham David I , Dominiczak Anna F , Macrae I Mhairi
Published: February 2004

We previously reported that during pro-estrus (high endogenous estrogen levels), brain damage after middle cerebral artery occlusion (MCAO) was reduced in stroke-prone spontaneously hypertensive rats (SHRSP) but not in normotensive Wistar Kyoto rat (WKY). In the present study, we examined the effect of exogenous estrogen on brain damage after MCAO in SHRSP and WKY. A 17β-estradiol (0.025mg or 0.25mg, 21 day release) or matching placebo pellet was implanted into ovariectomized WKY and SHRSP (3 to 4 months old) who then underwent distal diathermy-induced MCAO 2 weeks later. Plasma 17β-estradiol levels for placebo and 17β-estradiol groups were as follows: WKY 0.025 mg 16.4 ± 8.5 (pg/mL, mean ± SD) and 25.85 ± 12.6; WKY 0.25 mg 18.2 ± 9.0 and 69.8 ± 27.4; SHRSP 0.25 mg 20.7 ± 8.8 and 81.0 ± 16.9. In SHRSP, infarct volumes at 24 hours after MCAO were similar in placebo and 17β-estradiol groups: SHRSP 0.025 mg 126.7 ± 15.3 mm3 (n = 6) and 114.0 ± 14.1 mm3 (n = 8) (not significant); SHRSP 0.25 mg 113.5 ± 22.3 mm3 (n = 8) and 129.7 ± 26.2 mm3 (n = 7) (not significant), respectively. In WKY, 17β-estradiol significantly increased infarct volume by 65% with 0.025mg dose [36.1 ± 20.7 mm3 (n = 8) and 59.7 ± 19.3 mm3 (n = 8) ( P = 0.033, unpaired t-test)] and by 96% with 0.25 mg dose [55.9 ± 36.4 mm3 (n = 8) and 109.7 ± 6.7 mm3 (n = 4) ( P = 0.017)]. Thus, 17β-estradiol increased stroke damage in normotensive rats with no significant effect in stroke-prone rats. Despite being contrary to our hypothesis, our findings add substance to the recently reported negative effects of 17β-estradiol in clinical studies.
The US education system for the non‐American faculty member: an interview with Leonard Waks
Authors: Waks Leonard , Sandelands Eric
Published: February 2004

In interview format this paper provides an introduction to the US education system for the non‐American faculty member, focusing primarily on the university sector. Issues addressed include: key differences inherent in the US system (versus the majority of the world); the structure of education; the role of the individual states and that of the federal government; funding; accreditation; faculty assessment and promotion; and the practicalities of teaching for an American university.
Continuing new welding developments at Weldex show
Authors: Rooks Brian
Published: February 2004

This paper reviews the Weldex exhibition held at the NEC in Birmingham in November 2003. Highlights of the show included VirtualArc from ABB, which is able to predict weld conditions using physics of the arc, the hybrid MSG‐laser welding process from Cloos and a new spot weld‐specific Motoman robot. Several manufacturers displayed off‐the‐shelf “plug and weld” cells including Cloos, Fanuc and Autotech Robotics. Servo controlled guns were also featured by Motoman Robotics and Rexroth Bosch. The latter also promoted its ultrasonic weld monitoring systems that integrate with Rexroth's medium frequency welding systems for high quality assurance spot welding. Finally, a new laser seam tracker from Micro Epsilon is described.
A modular approach for the design of the Alicia3 climbing robot for industrial inspection
Authors: Longo Domenico , Muscato Giovanni
Published: February 2004

The system proposed in this paper is the Alicia3 robot, which is based on the Alicia II module. Its aim is to inspect non‐porous vertical walls like those of aboveground petrochemical tanks, with a wide range of surface materials and cleanliness levels. To meet this aim, pneumatic‐like adhesion has been selected for the system. The system is also required to move over the surface at a suitable speed, to pass over obstacles and to have a suitable payload to carry mission‐specific instrumentation. The robot design mainly aimed at finding a solution with a high degree of modularity, so that it can easily be disassembled for maintenance purposes and to replace consumable parts such as the wheels and the sealing, making its design easier. Some onboard control algorithms have also been introduced to increase system reliability and reduce energy consumption.
Adding extra sensitivity to the SMART non‐linear actuator using sensor fusion
Authors: Montes H. , Pedraza L. , Armada M. , Akinfiev T. , Caballero R.
Published: February 2004

The prospect of using humanoid robots in practical applications attracts an important research effort and the latest steps forward in robot technology show many remarkable achievements where design aspects, control systems and software evolution regarding humanoid machines have been realised. While aiming to improve humanoid robots' overall performance, it is required that they could work for a long time spending minimum energy without losing their kinematic skills. In this direction, a new kind of non‐linear actuator, SMART, based on quasi‐resonance principle, has been developed by the Industrial Automation Institute to improve the overall performance of biped locomotion.
Biomimicing motion control of the WorkPartner robot
Authors: Halme Aarne , Luksch Tobias , Ylönen Sami
Published: February 2004

WorkPartner (WP), is the prototype of a mobile centaur‐like service robot designed to work interactively with humans in an outdoor environment. It moves using four wheeled legs and has a human‐like upper body. Tasks executed by the robot are similar to those that a human can do; the robot may replace or work together with people. Mobility is based on a hybrid system, which combines the benefits of both legs and wheels to provide good terrain negotiating capability and a large velocity range on variable ground. The robot is powered by a hybrid power system with electrical actuation and energy storage in the form of gasoline. The robot is equipped with a human‐like two‐hand manipulator. The long‐term goal is to develop an adaptive and learning robot, which can carry tools and work interactively with humans.
Playing truant within organisations
Authors: Sanders Karin
Published: February 2004

This study focuses on the relationship between informal relationships, work ethics and (short‐time) absenteeism. According to self‐categorisation theory, which elaborates on the social identity theory, hypotheses were formulated for the relationship between consensus in work ethics within teams, informal relationships (cohesiveness) and short‐term absenteeism. The hypotheses were tested within two Dutch organisations: study 1 concerns a housing corporation (n=53, eight teams), and study 2 concerns a nursing home (n=97, nine teams). As expected, consensus in work ethics and cohesiveness within a team were positively related. Results from multi‐level analyses showed as expected, a negative relationship between cohesiveness within a team and short‐term absenteeism of employees. Furthermore, an interaction‐effect was found in the first study, but not in the second: the more cohesive the team, the stronger the relationships between work ethics and short‐term absenteeism. Findings are discussed in terms of recommendations for further research and practical implications.
The normative imperatives of business and marketing strategy: grounding strategy in resource‐advantage theory
Authors: Hunt Shelby D. , Derozier Caroline
Published: February 2004

Determining the strategic thrust of the firm, it may be argued, is the principal task of top management. This task is aided by recent theories of business and marketing strategy, including the normative imperatives based on industry factors, resource factors, competences, market orientation, and relationship marketing. Choosing wisely from among the various theories of strategy requires an accurate understanding of the contexts of competition. This article argues that resource‐advantage theory, an evolutionary, disequilibrium‐provoking process theory of competition, provides that understanding. That is, resource‐advantage theory grounds theories of business and marketing strategy.
The Effect of Synchronous and Asynchronous CMC on Oral Performance in German
Authors: Abrams Zsuzsanna Ittzes
Published: February 2004

It has been frequently suggested that computer–mediated–communication (CMC) can help learners improve their oral proficiency. This study tested that suggestion by comparing the performance of 3 groups of learners (a control group, a synchronous CMC group, and an asynchronous CMC group) on 3 oral discussions tasks during the course of 1 semester. The number of idea units and words, the lexical richness and diversity, and the syntactic complexity of learner language served as dependent variables. Although this study confirmed a previously reported increase in quantity of language produced by students in the synchronous CMC group compared to the other two groups, the asynchronous CMC group did not outperform the control group. Furthermore, analyses of the quality of language indicated no significant differences among the 3 groups either lexically or syntactically.
Restoration of morphological and functional integrity in the regenerating eye of the giant African land snail Achatina fulica
Authors: Bobkova Marina V. , Tartakovskaya Olga S. , Borissenko Serguei L. , Zhukov Valery V. , Meyer‐Rochow Victor B.
Published: February 2004

To determine whether vision returns to its original state following eye removal in Achatina fulica, light and electron microscope examinations, electrophysiological recordings and behavioural tests were carried out on the regenerating snails. Reparative morphogenesis can result in the restoration of the peripheral sense organ even in the absence of complete regrowth of the tentacle, but it can also lead to the formation of aberrant regenerates. We found that anatomically and ultrastructurally the eyes of the ‘most normal’ regenerates were basically the same as the original eyes. Under normal conditions each eye is composed of a principal and an accessory eye, both sharing a common cornea. The only difference between regenerated and native eyes is the smaller size of the former, as a result of a reduced number of retinal cells. Electroretinographic responses revealed that the molecular mechanism of phototransduction is restored, in principle, but that flicker fusion frequency in the regenerated eye is significantly lower than in the normal eye. The directional movement to a visual stimulus (a black stripe of 45° width) had not completely recovered even 6 months after amputation. This suggests that the central projections of the optic nerve had not become fully re‐established at the time of testing.
Ultrastructure of an integumental organ with probable sensory function in Paragordius varius (nematomorpha)
Authors: Schmidt‐Rhaesa Andreas
Published: February 2004

The cuticle of late parasitic stages of Paragordius varius (Leidy, 1851) is composed of a layer with large fibres and a second layer (often named the areolar layer) distal from it. In this paper, organs are described that start at the basal side of the epidermis, pass the epidermis and the fibrous layer of the cuticle and merge with large, cushion‐like structures in the distal layer of the cuticle. The epidermal part of the organs is composed of darkly stained cells, which are probably in contact with the basi‐epidermal nervous system. Up to four processes of this cell traverse the cuticle. These processes might include cilia, because they contain microtubule‐like structures. The probable connection to nerve cells and the connection to the cushion‐like structures in the outer cuticular layer make it likely that the organs described here are sensory in function.
Sperm ultrastructure of the Brazilian Amazon poison frogsEpipedobates trivittatusandEpipedobates hahneli(Anura, Dendrobatidae)
Authors: Aguiar‐Jr Odair , Lima Albertina P. , Báo Sônia N. , Recco‐Pimentel Shirlei M.
Published: February 2004

The sperm ultrastructure ofEpipedobates trivittatusandE. hahneliis described. The spermatological characteristics are identical in both species, except for the extension of the acrosomal vesicle. The structure of the acrosomal complex is shared with species of the Bufonoidea neobatrachian lineage, which differs from the condition observed in species included in the ranoid lineage. The phylogenetic significance of the mitochondrial collar, also seen in Eubufonoidea groups, is still unclear. Also the significance of the alternative mitochondrial arrangement seen here is unclear. The perpendicular arrangement of the centrioles is also shared with the Bufonoidea and is considered a synapomorphic condition. An expanded undulating membrane and the absence of a juxtaxonemal fibre appear to be apomorphic characteristics of dendrobatid species, as also observed (homoplastically) for species ofLitoriaandCyclorana. However, the notable expansion of the undulating membrane appears to be an autapomorphy of Dendrobatidae frogs. The ultrastructural data presented here do not support the proposed placement ofE. trivittatusin a separate genus.
Observations of spermiogenesis and epididymal sperm maturation in the rufous hare wallaby, Lagorchestes hirsutus (Metatheria, Mammalia)
Authors: Johnston S. D. , Daddow L. , Carrick F. N. , Jamieson B.
Published: February 2004

Acrosomal development in the early spermatid of the rufous hare wallaby shows evidence of formation of an acrosomal granule, similar to that found in eutherian mammals, the Phascolarctidae and Vombatidae. Unlike the other members of the Macropodidae so far examined, the acrosome of this species appears to be fully compacted at spermiation and extends evenly over 90% of the dorsal aspect of the nucleus. During spermiogenesis, the nucleus of the rufous hare wallaby spermatid showed evidence of uneven condensation of chromatin; this may also be related to the appearance of unusual nucleoplasm evaginations from the surface of the fully condensed spermatid. This study was unable to find evidence of the presence of Sertoli cell spurs or nuclear rotation during spermiogenesis in the rufous hare wallaby. The majority of spermatozoa immediately before spermiation had a nucleus that was essentially perpendicular to the long axis of the sperm tail. Nuclei of spermatozoa found in the process of being released or isolated in the lumen of the seminiferous tubule were rotated almost parallel to the long axis of the flagellum; complete parallel alignment occurred during epididymal maturation. At spermiation spermatozoa have characteristically small cytoplasmic remnants compared to those of other macropods. Unlike the majority of macropodid spermatozoa so far described, the spermatozoa of the rufous hare wallaby showed little evidence of morphological change during epididymal transit. There was no formation of a fibre network around the midpiece or of plasma membrane specializations in this region; the only notable change was a distinctive flattening of midpiece mitochondria and scalloping of the anterior mitochondrial sheath to accommodate the sperm head. Preliminary evidence from spermiogenesis and epididymal sperm maturation supports the classification of the rufous hare wallaby as a separate genus but also indicates that its higher taxonomic position may need to be re‐evaluated.
Movable Singularities of a Class of Nonlinear Ordinary Differential Equations of Arbitrary Order
Authors: Sobolevsky S.
Published: February 2004

In this paper we consider nonlinear ordinary differential equations y(n)=F(y′, y, x) of arbitrary order

n≥ 3, where F is algebraic in

y, y′ and locally analytic in x. We prove that for

n > 3 these equations always admit movable branch points. In the case

n= 3 these equations admit movable branch points unless they are of the known class

y′′′=a(x)(y′)2+ (b2(x)y2+b1(x)y+b0(x))y′+ (c4(x)y4+c3(x)y3+c2(x)y2+c1(x)y+c0(x)), where

a, bj, cj are locally analytic in x.
Energy Dissipated Across Shocks in Weak Solutions of Conservation Laws
Authors: Srinivasan Gopala Krishna , Sharma V. D.
Published: February 2004

Manipulation of conservation laws through multiplication by mappings of the unknown function result in singular terms that are densities supported on the discontinuity locus. We derive an expression for these singular terms which have been interpreted as the energy dissipated at the shocks. As an application, the expression for these singular terms is obtained from the transport equation governing the propagation of small amplitude high frequency waves in hyperbolic conservation laws. Analogous formulas are obtained for rich systems in several space dimensions.
A Modal Analysis of Resonance during the Whole‐Body Vibration
Authors: Yue Z. , Mester J.
Published: February 2004

The mechanism of resonance of a damping system of multi‐degrees of freedom such as the human body and the dependence of resonance on system parameters, particularly on the damping level, are studied in terms of detailed mathematical solutions of both the whole‐body vibrations and the eigen modes for a simple model. It is revealed that resonance would only occur near the eigen frequencies of neutral modes for which the complex eigen frequencies of the corresponding damping modes for the given damping level of the system have not moved far from the starting point (damping‐free case) along the corresponding tracks in the plane of complex eigen frequency yet. The major resonance would occur near the eigen frequency of the neutral mode where the modulus of the characteristic function of the system has the strongest, i.e., the deepest and sharpest, local minimum. For the present model, this neutral mode is the lowest neutral mode. It is found that the resonance and eigen frequencies increase with the stiffness of muscles and decrease with the body mass, with the portion of wobbling mass in the upper body, and with the portion of upper body mass in the whole body. Both the modal analysis and the analysis of the whole‐body vibration show that the phase differences among different parts of the system are still small at the unique or the lowest resonance frequency and increase dramatically only when the frequency of the vibrating source goes beyond the resonance frequency. Thus, some effects of body vibrations, e.g., internal loads, may reach their maximum not at the resonance frequency, but at a frequency somewhat higher than the resonance frequency. This may account for the fact that the frequency ranges for abdominal pain and for lumbosacral pain caused by body vibrations are not exactly the same as the frequency range for major body resonance but shifted to somewhat higher frequency ranges. It is therefore suggested that the frequency used for strength training in terms of vibrating devices should be above 20 Hz in order to avoid not only the major resonance but also the maximal internal loads.
Personality Factors in Older Women's Perceived Susceptibility to Diseases of Aging
Authors: Gerend Mary A. , Aiken Leona S. , West Stephen G.
Published: February 2004

Abstract
Personality correlates of older women's perceived susceptibility to breast cancer, heart disease, and osteoporosis were examined in a community sample of 312 women aged 40–86. A latent factor of general perceived susceptibility to disease was shown to underlie disease‐specific perceptions of susceptibility. Affect‐related personality traits (neuroticism, extraversion, optimism, worry, and self‐deceptive enhancement) and internal and chance health locus of control predicted general perceived susceptibility. Perceived disease characteristics (e.g., perceived controllability, severity) and the use of cognitive heuristics (i.e., perceived similarity to those who contract each disease) also displayed marked consistency across the three distinct diseases. Finally, our results suggested that general beliefs about the characteristics of health threats and the use of cognitive heuristics may mediate the link between personality traits and perceived risk.
A Longitudinal Study of the Relationships Between Conscientiousness and the Social‐ Environmental Factors and Substance‐Use Behaviors That Influence Health
Authors: Roberts Brent W. , Bogg Timothy
Published: February 2004

The present study tested the relationships among conscientiousness‐related traits, social‐environmental factors that affect health, and substance‐use behaviors across a 30‐year period from age 21 to age 52 in the Mills Longitudinal study of women (N=99). Results showed that the trait of social responsibility (a facet of conscientiousness) assessed at age 21 predicted family, work, and substance use outcomes at midlife (age 43 and age 52). In turn, marital quality, duration of marriage, divorce, participating in paid work, status level of work, and marijuana consumption were associated with changes in social responsibility. The implications for personality, health, and personality development are discussed.
The Effect of Daily Stress, Personality, and Age on Daily Negative Affect
Authors: Mroczek Daniel K. , Almeida David M.
Published: February 2004

Abstract The current study examined whether stress reactivity becomes stronger or weaker with age. Daily stress and daily negative affect were modeled using 1,012 subjects from the National Study of Daily Events (NSDE), an 8‐day daily diary study. Age ranged from 25 to 74. Data were modeled using within‐person HLM techniques. Daily stress and neuroticism interacted in their effect on daily negative affect. There was a stronger association between daily stress and negative affect for persons high in neuroticism as compared to those low on the trait. In addition, daily stress and age interacted in their effect on daily negative affect. There was a stronger association between daily stress and negative affect for older as compared to younger adults. Results suggest heightened reactivity to stressors in older adulthood, perhaps due to kindling effects. Changes in the aging brain may explain this effect. Our investigations illuminate the complexities that characterize the set of associations among negative affect, stress, personality, and age, and point to potential aging or cohort effects.
The Effect of Health Value and Ethnicity on the Relationship Between Hardiness and Health Behaviors
Authors: Harris Shanette M.
Published: February 2004

Associations among hardiness, health value, and health protective behaviors were examined as a function of ethnicity among 80 African American and 100 European American college students. The role of health value as moderator versus mediator in the hardiness–health behavior link was explored. Racial differences in correlations among hardiness, control, and commitment were found, with stronger relations for African American than European Americans. Moderate positive relations between hardiness, control, commitment, and health value for African American, as contrasted with weak relations between commitment and health value for European Americans, were also shown. A partial mediational effect for health value with personal distress and moderator effects for health value with personal distress and health habits were found for African American only. Race predicted hardiness variables, tobacco and alcohol use, personal distress, and health habits beyond what was accounted for by occupation and income. The ramifications of these data with regard to future studies on hardiness, health value, and health behaviors for African American are discussed.
Contact allergy to ingredients of hair cosmetics in female hairdressers and clients – an 8‐year analysis of IVDK* data
Authors: Uter Wolfgang , Lessmann Holger , Geier Johannes , Schnuch Axel
Published: February 2004

Not only hairdressers, but also their clients or home‐users of hair cosmetic products may become sensitized to one of the product constituents. The present analysis addresses the question whether the pattern of sensitization is different in these 2 groups and includes female patients who consulted with the participating centres of the IVDK (http://www.ivdk.org) between 1995 and 2002, and in whom hair cosmetics have been considered as being causative of their contact dermatitis. Among these, 2 subgroups were identified: (i) patients, currently or previously working as hairdressers, diagnosed with occupational skin disease (H, n = 884) and (ii) patients who never worked as hairdressers, i.e. clients (C, n = 1217). Previous atopic eczema was twice as common among H, who were also much younger (median age 24 versus 46 in C). Analysis of sensitization frequencies and patterns showed the well‐known decline of contact allergy to glyceryl monothioglycolate (GMTG) in H from 31.2% to 8.5%. Among the C, 1.7% were allergic to GMTG. Concerning p‐phenylenediamine, a steady decline from 27.6% to 17.2% was observed in H, while no trend was found in C (12.6% and 16.6% in the first and the last 2‐year period, respectively). Conversely, a very slight decline of p‐toluenediamine sensitization was observed in H (from 29.5% to 24.8%), while at the same time a significant increase was noted in C (from 8.7% to 16.7%). A slighter increase was also noted with ammonium persulfate in C (3.1–6.8%), while the proportion of H sensitized remained largely constant at about 26%.
Rawlsian Civic Education: Political not Minimal
Authors: Victoria Costa M.
Published: February 2004

abstract  In Political Liberalism and later work John Rawls has recast his theory of justice as fairness in political terms. In order to illustrate the advantages of a liberal political approach to justice over liberal non‐political ones, Rawls discusses what kind of education might be required for future citizens of pluralistic and democratic societies. He advocates a rather minimal conception of civic education that he claims to derive from political liberalism. One group of authors has sided with Rawls’ political perspective and educational proposal, holding that a political approach and educational requirements that are not too demanding would have the advantage of being acceptable to a wide range of citizens with different religious, moral and philosophical perspectives. A second group of authors have criticized Rawls’ educational recommendations, holding that the production of a just society composed of reasonable citizens requires a more demanding civic education and, hence, that the political approach is not viable. The present paper argues that both groups are only partially right, and that there is a third way to understand civic education in Rawlsian terms, a way that is political but not minimal.
The Golden Rule and the Potentiality Principle: Future Persons and Contingent Interests
Authors: Chan Kai M. A.
Published: February 2004

abstract  Duties to future persons are central to numerous key ethical issues including contraception, abortion, genetic selection, treatment of the environment, and population control. Nevertheless, we still seem to be lacking Parfit's ‘Theory X’, a general theory of beneficence whose appropriateness extends to future generations. Starting from the Golden Rule (TGR), R. M. Hare purportedly derived counterintuitive duties to potential people and ‘the potentiality principle’. However, I argue that Hare's derivation involves a hidden and unjustifiable extension from TGR, and show how the most plausible form of TGR is compatible with multiple contradictory principles for the treatment of future persons. I appeal to our own preferences to argue that one extension of TGR follows the spirit of TGR, while the other is deeply implausible. Using the plausible extension, I derive a Contingent Interests Principle (CIP) that offers much promise as Parfit's elusive Theory X. In contrast to Hare's interpretation of TGR, this application provides solid justification for rejecting the potentiality principle.
Carl Cohen's ‘Kind’ Arguments For Animal Rights and Against Human Rights
Authors: Nobis Nathan
Published: February 2004

abstract  Carl Cohen's arguments against animal rights are shown to be unsound. His strategy entails that animals have rights, that humans do not, the negations of those conclusions, and other false and inconsistent implications. His main premise seems to imply that one can fail all tests and assignments in a class and yet easily pass if one's peers are passing and that one can become a convicted criminal merely by setting foot in a prison. However, since his moral principles imply that nearly all exploitive uses of animals are wrong anyway, foes of animal rights are advised to seek philosophical consolations elsewhere. I note that some other philosophers’ arguments are subject to similar objections.