bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimating harvest schedules and profitability under the risk of fire disturbance
Authors: Peter Brian , Nelson John
Published: August 2005

Incorporating fire disturbance into sustainable forest management plans is necessary to provide estimates of variation around indicators for harvest levels, growing stock, profitability, and landscape structure. A fire disturbance model linked to a harvest simulator was used to estimate the probability of harvest shortages under a range of harvest levels and fire suppression scenarios. Results were then used to estimate "sustainable" harvest levels based on a risk tolerance to harvest shortages and the effects of fire suppression. On a 288 000 ha forest in northeastern British Columbia, the cost of historical fire disturbance was estimated at $4 million per year in terms of foregone harvest profits. Suppressing 98.3% of disturbance events to 30% of their historical size had a value of $1.8 million per year. Higher levels of risk tolerance were associated with increased harvest levels and short-term profits, but as timber inventories were drawn down, average long-term profits became volatile. The modelling framework developed here can help to determine resilient forest management strategies and estimate the future flow and variability of harvest volumes, profits, and landscape conditions.
Physiological Activity of Irradiated Green Tea Polyphenol on the Human Skin
Authors: An Bong-Jeun , Kwak Jae-Hoon , Son Jun-Ho , Park Jung-Mi , Lee Jin-Young , Park Tae Soon , Kim So-Yeun , Kim Yeoung-Sun , Jo Cheorun , Byun Myung-Woo
Published: August 2005

Physiological activity of irradiated green tea polyphenol on the human skin was investigated for further industrial application. The green tea polyphenol was separated and irradiated at 40 kGy by γ-ray. For an anti-wrinkle effect, the collagenase inhibition effect was higher in the irradiated sample (65.3%) than that of the non-irradiated control (56.8%) at 200 ppm of the concentration ( p < 0.05). Collagen biosynthesis rats using a human fibroblast were 19.4% and 16.3% in the irradiated and the non-irradiated polyphenols, respectively. The tyrosinase inhibition effect, which is related to the skin-whitening effect, showed a 45.2% and 42.9% in the irradiated and the non-irradiated polyphenols, respectively, at a 100 ppm level. A higher than 90% growth inhibition on skin cancer cells (SK-MEL-2 and G361) was demonstrated in both the irradiated and the non-irradiated polyphenols. Thus, the irradiation of green tea polyphenol did not change and even increased its anti-wrinkle, skin-whitening and anticancer effects on the human skin. The results indicated that irradiated green tea polyphenol can be used as a natural ingredient with excellent physiological functions for the human skin through cosmetic or food composition.
Acupuncture Stimulation for Motor Cortex Activities: A 3T fMRI Study
Authors: Jeun Sin-Soo , Kim Jeong-Seok , Kim Bum-Soo , Park Sang-Dong , Lim Eun-Chul , Choi Gi-Soon , Choe Bo-Young
Published: August 2005

The acupoint, GB34, located in the back of the knee, is known to be effective in recovering motor function after a stroke. This study uses a functional magnetic resonance imaging (fMRI) study with 3T scanner to investigate whether or not acupuncture of GB34 produces a significant response of the modulation of somatomotor areas. A fMRI of the whole brain was performed in ten normal healthy subjects during two task stimulations of acupuncture manipulation on GB34 and sham points, inserting and twisting the needle for 25 seconds at a rate of approximately 120 times per minute; the needle manipulation was paused for a duration of 25 seconds as a control state. The process was repeated four times to have four epochs of stimulation. Bilateral sensorimotor areas (BA 3, 4, 6 and 7) showed approximately 6% of stimulation-related BOLD signal contrast, whereas very few areas were activated when sham stimulation was given. Acupuncture stimulation in GB34 modulates the cortical activities of the somatomotor area in humans. The present findings may shed light on the CNS mechanism of motor function by acupuncture, and form a basis for future investigations of motor modulation circuits in stroke patients.
The Study of Chinese Medicinal Herbal Formula Shen San Fang in the Treatment of Experimental IgA Nephropathy
Authors: Zhong Qing , Leung Joseph C. K. , Chan Loretta Y. Y. , Tsang Anita W. L. , Chen Xian , Lai Kar Neng
Published: August 2005

IgA nephropathy (IgAN) is the most common primary glomerulonephritis worldwide, yet there is no effective or specific therapy. Shen San Fang (S3F) is a traditional Chinese herbal medicinal formula that has been used in China for many years to treat patients with hematuria. The aim of this study is to test the therapeutic value of S3F in an experimental model of IgAN. IgAN was induced in Lewis rats by continuous oral immunization with bovine gamma-globulin (BGG) in the drinking water for 8 weeks, followed by intravenous injection of 1 mg BGG daily for 3 successive days. The rats were randomly divided into four groups (five rats/group): control, control receiving S3F, induction of IgAN, and IgAN receiving S3F. S3F decoction was fed to rats beginning week 4 from the first day of oral sensitization with BGG. The S3F treatment was continued until the rats were sacrificed or for a 4-week period. Hematuria, renal immunohistochemistry for IgA and transforming growth factor-beta 1 (TGF-β1), renal histopathology, and renal content of TGF-β1 were measured. Rats developing IgAN had marked hematuria, profound mesangial proliferation and mesangial expansion, intense and diffuse glomerular IgA deposition, increased glomerular TGF-β1 expression, and raised renal TGF-β1 levels. S3F treatment resulted in a significant reduction of hematuria, decreased mesangial IgA deposition, weaker immunostaining of TGF-β1 in glomerulus, and a lower renal TGF-β1 concentration. Our animal data suggests a therapeutic value for the Chinese medicinal formula S3F in experimental IgAN. This beneficial effect was due to reduced glomerular IgA deposition and TGF-β1 expression. Our preliminary findings hold promise for future human therapy.
Morphological Studies on Crushed Sciatic Nerve of Rabbits with Electroacupuncture or Diclofenac Sodium Treatment
Authors: La Jie-Lian , Jalali Samina , Shami S. A.
Published: August 2005

Sciatic nerves of 15 rabbits were crushed by Halsted straight mosquito hemostat with 8-11 Newton force for 60 seconds on a point 5 mm above the knee joint, and then the rabbits were equally divided into three groups. The acupuncture group was treated by electroacupuncture on Huan Tiao and Wei Zhong points (25 minutes/day) for 7 days. The medicine group was treated with intramuscular administration of dicofenac sodium (15 mg) daily for 7 days. The control group was not treated. After treatment, the distal parts of crushed nerve were examined under light microscope, the densities of normal myelinated fibers in 0.126 mm2were counted, and the diameters of 20 normal myelinated fibers were measured for each animal. The results showed that the mean densities were 176.2 ± 5.953 in the acupuncture group, 118.2 ± 10.878 in the medicine group and 101.4 ± 8.548 in the control group. The mean values were significantly different between the acupuncture and medicine groups ( p < 0.01) and highly significant difference between the acupuncture and control groups ( p < 0.001); but there was no significant difference between the medicine and control groups ( p > 0.05). There are more small myelinated fibers (0–9 μm) in the acupuncture group than in the medicine and control groups ( p = 0.0028). The results revealed and confirmed that acupuncture promotes nerve regeneration; diclofenac sodium did not show such an effect. The present study demonstrates the positive effect of acupuncture on regeneration of a crushed sciatic nerve in the rabbits. And acupuncture is a better treatment for regeneration of crushed nerve than diclofenac sodium.
The evolving role of animal laboratories in physiology instruction
Authors: Ra'anan Alice W.
Published: August 2005

Laboratory exercises are intended to illustrate concepts and add an active learning component to courses. Since the 1980s, there has been a decline in animal laboratories offered in conjunction with medical physiology courses. The most important single reason for this is cost, but other contributing factors include the development of computer simulations, changes in medical education, and pressure from antivivisectionists. Unfortunately, the elimination of animal laboratories has occurred with relatively little consideration of the educational impact of this change. Although computer simulations are considered effective in helping students acquire basic physiological concepts, there is evidence some students acquire a more thorough understanding of the material through the more advanced and challenging experience of an animal laboratory. The fact that such laboratories offer distinct educational advantages should be taken into account when courses are designed.
The power of real-time PCR
Authors: Valasek Mark A. , Repa Joyce J.
Published: August 2005

In recent years, real-time polymerase chain reaction (PCR) has emerged as a robust and widely used methodology for biological investigation because it can detect and quantify very small amounts of specific nucleic acid sequences. As a research tool, a major application of this technology is the rapid and accurate assessment of changes in gene expression as a result of physiology, pathophysiology, or development. This method can be applied to model systems to measure responses to experimental stimuli and to gain insight into potential changes in protein level and function. Thus physiology can be correlated with molecular events to gain a better understanding of biological processes. For clinical molecular diagnostics, real-time PCR can be used to measure viral or bacterial loads or evaluate cancer status. Here, we discuss the basic concepts, chemistries, and instrumentation of real-time PCR and include present applications and future perspectives for this technology in biomedical sciences and in life science education.
Teaching glucocorticoid negative feedback and adrenocortical regulation using a classic paper by Dr. Dwight Ingle
Authors: Raff Hershel
Published: August 2005

Teaching glucocorticoid negative feedback and adrenocortical regulation using a classic paper by Dr. Dwight Ingle. Adv Physiol Educ29: 141–143, 2005; doi:10.1152/advan.00020.2005.—The American Physiological Society (APS) Legacy Project and its accompanying Essays on APS Classic Papers have allowed the scientific community on-line access to the entire collection of APS publications since their inception in 1898 ( http://www.the-aps.org/publications/legacy/ and http://www.the-aps.org/publications/classics/ ). The availability of the classic physiological studies provides a unique teaching opportunity. The classic paper of Dr. Dwight Ingle represents just such a study. Dr. Ingle demonstrated that, using only purified extracts of the pituitary (ACTH) and adrenal cortex (corticosterone) and hypophysectomized rats, he could establish several of the basic principles of the control of adrenal function and glucocorticoid negative feedback that are now standard teaching material in endocrinology. An annotated figure from Dr. Ingle's paper is provided, which, when assigned to undergraduate or graduate students, will allow discovery learning. Furthermore, the brilliance and imagination of the physiologists of the last century are highlighted, which allows an appreciation of the seminal work of our predecessors.
Lung endothelial cell proliferation with decreased shear stress is mediated by reactive oxygen species
Authors: Milovanova Tatyana , Chatterjee Shampa , Manevich Yefim , Kotelnikova Irina , DeBolt Kris , Madesh Muniswamy , Moore Jonni S. , Fisher Aron B.
Published: August 2005

Acute cessation of flow (ischemia) leads to depolarization of the endothelial cell (EC) membrane mediated by KATP channels and followed by production of reactive oxygen species (ROS) from NADPH oxidase. We postulated that ROS are a signal for initiating EC proliferation associated with the loss of shear stress. Flow cytometry was used to identify proliferating CD31-positive pulmonary microvascular endothelial cells (mPMVECs) from wild-type, Kir6.2−/−, and gp91 phox−/− mice. mPMVECs were labeled with PKH26 and cultured in artificial capillaries for 72 h at 5 dyn/cm2 (flow adaptation), followed by 24 h of stop flow or continued flow. ROS production during the first hour of ischemia was markedly diminished compared with wild-type mice in both types of gene-targeted mPMVECs. Cell proliferation was defined as the proliferation index (PI). After 72 h of flow, >98% of PKH26-labeled wild-type mPMVECs were at a single peak (PI 1.0) and the proportion of cells in the S+G2/M phases were at 5.8% on the basis of cell cycle analysis. With ischemia (24 h), PI increased to 2.5 and the ratio of cells in S+G2/M phases were at 35%. Catalase, diphenyleneiodonium, and cromakalim markedly inhibited ROS production and cell proliferation in flow-adapted wild-type mPMVECs. Significant effects of ischemia were not observed in Kir6.2−/− and gp91 phox−/− cells. ANG II activation of NADPH oxidase was unaffected by KATP gene deletion. Thus loss of shear stress in flow-adapted mPMVECs results in cell division associated with ROS generated by NADPH oxidase. This effect requires a functioning cell membrane KATP channel.
EGF stimulates proliferation of mouse embryonic stem cells: involvement of Ca2+ influx and p44/42 MAPKs
Authors: Heo Jung Sun , Lee Yun Jung , Han Ho Jae
Published: August 2005

We examined the effect of EGF on the proliferation of mouse embryonic stem (ES) cells and their related signal pathways. EGF increased [3H]thymidine and 5-bromo-2′-deoxyuridine incorporation in a time- and dose-dependent manner. EGF stimulated the phosphorylation of EGF receptor (EGFR). Inhibition of EGFR tyrosine kinase with AG-1478 or herbimycin A, inhibition of PLC with neomycin or U-73122, inhibition of PKC with bisindolylmaleimide I or staurosporine, and inhibition of L-type Ca2+ channels with nifedipine or methoxyverapamil prevented EGF-induced [3H]thymidine incorporation. PKC-α, -βI, -γ, -δ, and -ζ were translocated to the membrane and intracellular Ca2+ concentration ([Ca2+]i) was increased in response to EGF. Moreover, inhibition of EGFR tyrosine kinase, PLC, and PKC completely prevented EGF-induced increases in [Ca2+]i. EGF also increased inositol phosphate levels, which were blocked by EGFR tyrosine kinase inhibitors. Furthermore, EGF rapidly increased formation of H2O2, and pretreatment with antioxidant ( N-acetyl-l-cysteine) inhibited EGF-induced increase of [Ca2+]i. In addition, we observed that p44/42 MAPK phosphorylation by EGF and inhibition of EGFR tyrosine kinase, PLC, PKC, or Ca2+ channels blocked EGF-induced phosphorylation of p44/42 MAPKs. Inhibition of p44/42 MAPKs with PD-98059 (MEK inhibitor) attenuated EGF-induced increase of [3H]thymidine incorporation. Finally, inhibition of EGFR tyrosine kinase, PKC, Ca2+ channels, or p44/42 MAPKs attenuated EGF-stimulated cyclin D1, cyclin E, cyclin-dependent kinase (CDK)2, and CDK4, respectively. In conclusion, EGF partially stimulates proliferation of mouse ES cells via PLC/PKC, Ca2+ influx, and p44/42 MAPK signal pathways through EGFR tyrosine kinase phosphorylation.
Membrane cholesterol extraction decreases Na+ transport in A6 renal epithelia
Authors: Balut Corina , Steels Paul , Radu Mihai , Ameloot Marcel , Driessche Willy Van , Jans Danny
Published: August 2005

In this study, we have investigated the dependence of Na+ transport regulation on membrane cholesterol content in A6 renal epithelia. We continuously monitored short-circuit current ( Isc), transepithelial conductance ( GT), and transepithelial capacitance ( CT) to evaluate the effects of cholesterol extraction from the apical and basolateral membranes in steady-state conditions and during activation with hyposmotic shock, oxytocin, and adenosine. Cholesterol extraction was achieved by perfusing the epithelia with methyl-β-cyclodextrin (mβCD) for 1 h. In steady-state conditions, apical membrane cholesterol extraction did not significantly affect the electrophysiological parameters; in contrast, marked reductions were observed during basolateral mβCD treatment. However, apical mβCD application hampered the responses of Isc and GT to hypotonicity, oxytocin, and adenosine. Analysis of the blocker-induced fluctuation in Isc demonstrated that apical mβCD treatment decreased the epithelial Na+ channel (ENaC) open probability ( Po) in the steady state as well as after activation of Na+ transport by adenosine, whereas the density of conducting channels was not significantly changed as confirmed by CT measurements. Na+ transport activation by hypotonicity was abolished during basolateral mβCD treatment as a result of reduced Na+/K+ pump activity. On the basis of the findings in this study, we conclude that basolateral membrane cholesterol extraction reduces Na+/K+ pump activity, whereas the reduced cholesterol content of the apical membranes affects the activation of Na+ transport by reducing ENaC Po.
Identification of AQP5 in lipid rafts and its translocation to apical membranes by activation of M3 mAChRs in interlobular ducts of rat parotid gland
Authors: Ishikawa Yasuko , Yuan Zhenfang , Inoue Noriko , Skowronski Mariusz T. , Nakae Yoshiko , Shono Masayuki , Cho Gota , Yasui Masato , Agre Peter , Nielsen Søren
Published: August 2005

Aquaporin-5 (AQP5), an apical plasma membrane (APM) water channel in salivary glands, lacrimal glands, and airway epithelium, has an important role in fluid secretion. M3 muscarinic acetylcholine receptor (mAChR)-induced changes in AQP5 localization in rat parotid glands were investigated with immunofluorescence or immunoelectron microscopy, detergent solubility, and gradient density floatation assays. Confocal microscopy revealed AQP5 localization in intracellular vesicles of interlobular duct cells in rat parotid glands and AQP5 trafficking to the APM 10 min after injection of the mAChR agonist cevimeline. Conversely, 60 min after injection, there was a diffuse pattern of AQP5 staining in the cell cytoplasm. The calcium ionophore A-23187 mimicked the effects of cevimeline. Immunoelectron microscopic studies confirmed that cevimeline induced AQP5 trafficking from intracellular structures to APMs in the interlobular duct cells of rat parotid glands. Lipid raft markers flotillin-2 and GM1 colocalized with AQP5 and moved with AQP5 in response to cevimeline. Under control conditions, the majority of AQP5 localized in the Triton X-100-insoluble fraction and floated to the light-density fraction on discontinuous density gradients. After 10-min incubation of parotid tissue slices with cevimeline or A-23187, AQP5 levels decreased in the Triton X-100-insoluble fraction and increased in the Triton X-100-soluble fraction. Thus AQP5 localizes in the intracellular lipid rafts, and M3 mAChR activation induces AQP5 trafficking to the APM with lipid rafts via intracellular Ca2+ signaling and induces AQP5 dissociation from lipid rafts to nonrafts on the APM in the interlobular duct cells of rat parotid glands.
μ-Calpain and calpain-3 are not autolyzed with exhaustive exercise in humans
Authors: Murphy Robyn M. , Snow Rodney J. , Lamb Graham D.
Published: August 2005

μ-calpain and calpain-3 are Ca2+-dependent proteases found in skeletal muscle. Autolysis of calpains is observed using Western blot analysis as the cleaving of the full-length proteins to shorter products. Biochemical assays suggest that μ-calpain becomes proteolytically active in the presence of 2–200 μM Ca2+. Although calpain-3 is poorly understood, autolysis is thought to result in its activation, which is widely thought to occur at lower intracellular Ca2+ concentration levels ([Ca2+]i; ∼1 μM) than the levels at which μ-calpain activation occurs. We have demonstrated the Ca2+-dependent autolysis of the calpains in human muscle samples and rat extensor digitorum longus (EDL) muscles homogenized in solutions mimicking the intracellular environment at various [Ca2+] levels (0, 2.5, 10, and 25 μM). Autolysis of calpain-3 was found to occur across a [Ca2+] range similar to that for μ-calpain, and both calpains displayed a seemingly higher Ca2+ sensitivity in human than in rat muscle homogenates, with ∼15% autolysis observed after 1-min exposure to 2.5 μM Ca2+ in human muscle and almost none after 1- to 2-min exposure to the same [Ca2+]i level in rat muscle. During muscle activity, [Ca2+]i may transiently peak in the range found to autolyze μ-calpain and calpain-3, so we examined the effect of two types of exhaustive cycling exercise (30-s “all-out” cycling, n = 8; and 70% V̇o2 peak until fatigue, n = 3) on the amount of autolyzed μ-calpain or calpain-3 in human muscle. No significant autolysis of μ-calpain or calpain-3 occurred as a result of the exercise. These findings have shown that the time- and concentration-dependent changes in [Ca2+]i that occurred during concentric exercise fall near but below the level necessary to cause autolysis of calpains in vivo.
Influences of AT1 receptor blockade on tissue metabolism in obese men
Authors: Boschmann Michael , Engeli Stefan , Adams Frauke , Franke Gabriele , Luft Friedrich C. , Sharma Arya M. , Jordan Jens
Published: August 2005

ANG II applied to the interstitial space influences carbohydrate and lipid metabolism in a tissue-specific fashion. Thus endogenous ANG II may have a tonic effect on tissue metabolism that could be reversed with ANG II type 1 (AT1) receptor blockade, particularly during adrenergic stimulation. We studied 14 obese men. They were treated for 10 days with the AT1 receptor blocker irbesartan or with placebo in a double-blind and crossover fashion. At the end of each treatment period, we assessed skeletal muscle and adipose tissue metabolism using the microdialysis technique. The ethanol dilution technique was applied to follow changes in tissue blood flow. Measurements were obtained at baseline and during application of incremental isoproterenol concentrations through the microdialysis catheter. Blood pressure decreased from 133 ± 3/84 ± 3 to 128 ± 3/79 ± 2 mmHg for systolic and diastolic blood, respectively ( P = 0.02 and 0.006, respectively) with AT1 receptor blockade. Isoproterenol perfusion caused a dose-dependent increase in dialysate glycerol in adipose tissue and in skeletal muscle. Irbesartan slightly reduced the isoproterenol-induced glycerol response in adipose tissue ( P < 0.05 by ANOVA). Ethanol ratio, interstitial glucose supply, and lactate production in adipose tissue and skeletal muscle were similar with placebo and irbesartan. We conclude that AT1 receptor blockade in obese men does not reveal a major tonic ANG II effect on interstitial glucose supply, lipolysis, or glycolysis in skeletal muscle, either at rest or during β-adrenergic stimulation. Endogeneous ANG II may slightly increase adipose tissue lipolysis. The mechanism may promote the redistribution of triglycerides from adipose tissue toward other organs.
Role of AMPA Receptor Desensitization and the Side Effects of a DMSO Vehicle on Reticulospinal EPSPs and Locomotor Activity
Authors: Tsvyetlynska Nataliya A. , Hill Russell H. , Grillner Sten
Published: August 2005

Activation of the vertebrate locomotor network is mediated by glutamatergic synaptic drive, normally initiated by the brain stem. Previous investigations have studied the role of glutamate receptors, especially NMDA receptors, in generating and regulating locomotor pattern generation. Few studies, however, have focused on the role of AMPA receptors in shaping network activity, especially with regard to their rapid desensitization. It is important to determine whether AMPA receptor desensitization plays a role in regulating neuronal network activity. We examined this question on both the network and synaptic levels in the lamprey ( Lampetra fluviatilis) spinal cord using a selective and potent inhibitor of AMPA receptor desensitization, cyclothiazide (CTZ). The solvent dimethyl sulfoxide (DMSO) is commonly used to dissolve this drug, as well as many others. Unexpectedly, the vehicle alone already at 0.02%, but not at 0.01%, caused significant increases in excitatory postsynaptic potential (EPSP) amplitudes and NMDA-induced locomotor frequency. The results indicate that DMSO may have a profound influence when used ≥0.02%, a concentration 10–50 times less than that most commonly used. Subsequently we applied CTZ concentrations ≤10 μM (DMSO ≤0.01%). CTZ (1.25–5 μM) caused an appreciable and significant increase in EPSPs mediated by non-NMDA receptors and in both AMPA- and NMDA-induced locomotor frequency, but no effects on EPSPs mediated by NMDA receptors. From the effects of CTZ it is apparent that AMPA receptor desensitization plays an important role in determining locomotor frequency and that this is likely a result of its limiting function on AMPA receptor–mediated EPSPs.
Nicotinic Acetylcholine Receptor Subtypes Involved in Facilitation of GABAergic Inhibition in Mouse Superficial Superior Colliculus
Authors: Endo Toshiaki , Yanagawa Yuchio , Obata Kunihiko , Isa Tadashi
Published: August 2005

The superficial superior colliculus (sSC) is a key station in the sensory processing related to visual salience. The sSC receives cholinergic projections from the parabigeminal nucleus, and previous studies have revealed the presence of several different nicotinic acetylcholine receptor (nAChR) subunits in the sSC. In this study, to clarify the role of the cholinergic inputs to the sSC, we examined current responses induced by ACh in GABAergic and non-GABAergic sSC neurons using in vitro slice preparations obtained from glutamate decarboxylase 67-green fluorescent protein (GFP) knock-in mice in which GFP is specifically expressed in GABAergic neurons. Brief air pressure application of acetylcholine (ACh) elicited nicotinic inward current responses in both GABAergic and non-GABAergic neurons. The inward current responses in the GABAergic neurons were highly sensitive to a selective antagonist for α3β2- and α6β2-containing receptors, α-conotoxin MII (αCtxMII). A subset of these neurons exhibited a faster α-bungarotoxin-sensitive inward current component, indicating the expression of α7-containing nAChRs. We also found that the activation of presynaptic nAChRs induced release of GABA, which elicited a burst of miniature inhibitory postsynaptic currents mediated by GABAAreceptors in non-GABAergic neurons. This ACh-induced GABA release was mediated mainly by αCtxMII-sensitive nAChRs and resulted from the activation of voltage-dependent calcium channels. Morphological analysis revealed that recorded GFP-positive neurons are interneurons and GFP-negative neurons include projection neurons. These findings suggest that nAChRs are involved in the regulation of GABAergic inhibition and modulate visual processing in the sSC.
Excitatory Actions of Dopamine Via D1-Like Receptors in the Rat Lateral Geniculate Nucleus
Authors: Govindaiah G. , Cox Charles L.
Published: August 2005

The excitability of relay neurons in the dorsal geniculate nucleus (dLGN) can be altered by a variety of neuromodulators. The dLGN receives substantial dopaminergic input from the brain stem, and this innervation may play a crucial role in the gating of visual information from the retina to visual neocortex. In this study, we investigated the action of dopamine on identified dLGN neurons using whole cell recording techniques. Dopamine (2–200 μM) produced a membrane depolarization in >95% of relay neurons tested but did not alter excitability of dLGN interneurons. The D1-like dopamine receptor agonist SKF38393 (2–50 μM) produced a similar depolarization in dLGN relay neurons. However, the D2-like receptor agonists, bromocriptine (25–50 μM) and PPHT (1–50 μM), did not alter the membrane potential of relay neurons. SCH23390 (5–10 μM), a D1-like receptor antagonist, attenuated the depolarizing actions of both dopamine and SKF38393 . Furthermore, the excitatory actions of dopamine and SKF38393 were attenuated by ZD7288, a specific antagonist for the hyperpolarization activated mixed cation current, Ih. Our data suggest that dopamine, acting via D1-like receptors, activates Ih leading to a membrane depolarization. Through the modulation of dLGN neuronal excitability, ascending and descending activating systems may not only control the state of the thalamus such as the transition from slow-wave sleep to waking but also regulate the efficacy of information transfer during waking states.
Imaging of Ca2+Dynamics Within the Presynaptic Terminals of Salamander Rod Photoreceptors
Authors: Steele Ernest C. , Chen Xiaoming , Iuvone P. Michael , MacLeish Peter R.
Published: August 2005

Although the overall importance of Ca2+as a mediator of cell signaling and neurotransmitter release has long been appreciated, the details of Ca2+dynamics within the inner segments of vertebrate rod photoreceptors are just beginning to be elucidated. Even less is known regarding Ca2+dynamics within the rod presynaptic terminal compartment. Using fura-2 to report changes in intracellular Ca2+, we imaged the responses of enzymatically dissociated salamander rod photoreceptors retaining intact axons and presynaptic terminals stimulated with a brief depolarizing puff of KCl (30 mM pipette concentration). In the vast majority of cells, the response was a large increase in Ca2+levels in the terminal compartment, but not in the soma. In contrast, rods exhibited a substantial elevation in somatic Ca2+levels when depolarized with a brief puff of 100 mM KCl (pipette concentration). These data are consistent with previously reported differences in Ca2+buffering mechanisms within the somatic and terminal compartments. Additionally, they may reflect the presence of Ca2+channels having distinct properties within the membranes of the two compartments. Consistent with this hypothesis, fluorescent immunocytochemistry using an antibody against the L-type Ca2+channel Cav1.2 (α1C) subunit and semiquantitative confocal microscopy revealed a high concentration of immunoreactivity in the membranes of terminals of intact rods compared with the somata. Further investigations using enzymatically dissociated preparations of intact rod photoreceptors retaining their presynaptic terminals will allow further testing of these and other hypotheses regarding the compartmentalized regulation of Ca2+dynamics within rod photoreceptors.
Proportion of N-Type Calcium Current Activated by Action Potential Stimuli
Authors: King J. Darwin , Meriney Stephen D.
Published: August 2005

N-type calcium currents are important in many neuronal functions, including cellular signaling, regulation of gene expression, and triggering of neurotransmitter release. Often the control of these diverse cellular functions is governed by the spatial and temporal patterns of calcium entry in subcellular compartments. Underlying this issue is the effectiveness of action potentials at triggering calcium channel opening. Chick ciliary ganglion neurons were used as model cells to study the activation of N-type calcium current during action potential depolarization. Several different action potential shapes were recorded, used as voltage command templates, and altered such that control action potential–evoked currents could be compared with those elicited by broadened action potential commands. Depending on the action potential shape used to activate calcium currents in chick ciliary ganglion neurons, and the temperature at which recordings were performed, varying proportions ( I/ Imax) of N-type calcium current could be activated. The largest proportion measured occurred using a broad ciliary ganglion cell soma action potential to activate calcium current at 37°C (100%). The smallest proportion measured occurred using a fast, high-temperature–adjusted frog motoneuron nerve terminal action potential to activate calcium current at room temperature (10%). These data are discussed with respect to the impact on cellular signaling and the regulation of transmitter release.
A two‐weight estimate for a class of fractional integral operators with rough kernel
Authors: Ding Yong
Published: August 2005

We prove that the operators in a class of rough fractional
integral operators and the related maximal
operators are bounded from Lp(vp) to Lq(uq) with
weight pair (u, v).
Existence and algorithm of solutions for generalized nonlinearvariational‐like inequalities
Authors: Liu Zeqing , Sun Juhe , Shim Soo Hak , Kang Shin Min
Published: August 2005

We introduce and study a new class of generalized nonlinear
variational‐like inequalities. Under suitable conditions, we prove
the existence of solutions for the class of generalized nonlinear
variational‐like inequalities. A new iterative algorithm for
finding the approximate solutions of the generalized nonlinear
variational‐like inequality is given and the convergence of the
algorithm is also proved. The results presented in this paper
improve and generalize some results in recent literature.
Fixed point index approach for solutions of variationalinequalities
Authors: Lai Yisheng , Zhu Yuanguo , Deng Yinbing
Published: August 2005

By using fixed point index approach for multivalued mappings, the
existence of nonzero solutions for a class of generalized
variational inequalities is studied in reflexive Banach space.
One of the mappings concerned here is coercive or monotone and the
other is set‐contractive or upper semicontinuous.
On the constant in the nonuniform version of the Berry‐Esseen theorem
Authors: Neammanee K.
Published: August 2005

In 2001, Chen and Shao gave the nonuniform estimation of the rate
of convergence in Berry‐Esseen theorem for independent random
variables via Stein‐Chen‐Shao method. The aim of this paper is to
obtain a constant in Chen‐Shao theorem, where the random variables
are not necessarily identically distributed and the
existence of their third moments are not assumed. The bound is
given in terms of truncated moments and the constant obtained is
21.44 for most values. We use a technique called Stein′s method,
in particular the Chen‐Shao concentration inequality.
Characterization of the stability set for non‐differentiable fuzzyparametric optimization problems
Authors: Kassem Mohamed Abd El-Hady
Published: August 2005

This note presents the characterization of
the stability set of the first
kind for multiobjective nonlinear programming (MONLP) problems
with fuzzy parameters either in the constraints or in
the objective functions without any differentiability
assumptions. These fuzzy parameters are characterized
by triangular fuzzy numbers (TFNs). The existing
results concerning the parametric space in convex programs are
reformulated to study for multiobjective nonlinear programs under
the concept of α‐Pareto optimality.
Memory Tales: Representations of Shembe in the Cultural Discourse of African Renaissance
Authors: Heuser Andreas
Published: August 2005

The discourse on African Renaissance in South Africa shapes the current stage of a post-apartheid political culture of memory. One of the frameworks of this negotiation of the past is the representation of religion. In particular, religious traditions that formerly occupied a marginalised status in Africanist circles are assimilated into a choreography of memory to complement an archive of liberation struggle. With respect to one of the most influential African Instituted Churches in South Africa, the Nazareth Baptist Church founded by Isaiah Shembe, this article traces an array of memory productions that range from adaptive and mimetic strategies to contrasting textures of church history. Supported by a spatial map of memory, these alternative religious traditions are manifested inside as well as outside the church. Against a hegemonic Afrocentrist vision, they are assembled from fragments of an intercultural milieu of early Nazareth Baptist Church history.
'Building A New Eden': Lutheran Church Youth Choir Performances in Tanzania
Authors: Bjerk Paul
Published: August 2005

A study of three songs by a Tanzanian youth choir reveals a synthesis of historical and intellectual sources ranging from pre-colonial social philosophy to Lutheran theology to Nyerere's Ujamaa socialism. The songs show how the choir performances break down the barrier between Bourdieu's realms of the disputed and undisputed. In appropriating an active role in shaping Christian ideology, the choir members reinterpret its theology into something wholly new and uniquely Tanzanian. Thus they appropriate an authoritative voice that shapes the basic societal concepts about the nature of life and society. They envision themselves as essential workers in an ongoing sacred task of building a modern Tanzanian nation in the image of a new Eden.
The Daily Cycle of Low-Frequency Elephant Calls and Near-Surface Atmospheric Conditions
Authors: Garstang Michael , Fitzjarrald David R. , Fristrup Kurt , Brain Conrad
Published: August 2005

Elephant low-frequency calls and atmospheric conditions that influence the transmission and detection of these calls were recorded at a fixed location over a period of about 3 weeks at the end of the dry season in the Etosha National Park, Namibia. A bimodal distribution in elephant call detections is observed, with the primary maximum (42% of all calls) occurring in a 3-h period following sunset and a secondary maximum (29% of all calls) in a 2-h period following sunrise.

This distribution in calls detected is shown to depend upon marked and regular changes over 24 h in near-surface atmospheric stability and velocity, which determine propagation ranges. The observed bimodal distribution of calls detected depends upon these changes in atmospheric conditions as well as the location of the caller and the rate of calling. The findings are supported by results from an atmospheric acoustic model but are at variance with observations of the number of calls made from collared elephants in markedly different habitat.

Detection of calls heard at a location remote from the caller represents a valuable and noninvasive research and applied tool that, however, must take note of atmospheric conditions that govern the propagation and reception of such signals.
Morphology and Mechanical Properties of Foamed Polyethylene-Polypropylene Blends
Authors: Tejeda Elias Herrera , Sahagún Carlos Zepeda , González-Núñez Rubén , Rodrigue Denis
Published: August 2005

Blends of high-density polyethylene and polypropylene are foamed by means of extrusion using azodicarbonamide as a chemical blowing agent to study the effect of blending on the morphological and mechanical properties. At 0.5 wt% of blowing agent, optimum foam density is found to be around 417 kg/m3 for each blend composition, but the average cell size ranges between 130 and 301 mm depending on the blend composition. It is believed that the dispersed polymer phase acts as nucleating sites producing foams with smaller cell sizes. Owing to the incompatibility between both the polymers, the best tensile and impact properties are obtained for neat polymers. Simple semi-empirical models are proposed to predict the tensile and impact properties of the foams.
Study on the Optimum Feed Compositions of Biodegradable Cellular Foams Blend with Talc Powder (Talc)
Authors: Peng Jinchyau , Wei Kaishuen , Lui Wai-Bun
Published: August 2005

Response surface methodology (RSM) is used to analyze the effect of polyvinyl alcohol (PVA) and talc powder (talc) on the objective (radial expansion ratio, bulk density, compressibility, and spring index) attributes of a biodegradable cushioning extrudate. A rotatable central composite design (CCD) is used to develop models for the objective responses. The experiments are run at 125 C with a feed rate of 27.8 L/h, a screw speed of 215 rpm, and a die diameter of 3.92 mm. Responses are most affected by changes in PVA levels and to a lesser extent by talc levels. Individual contour plots of the different responses are overlaid, and regions meeting the optimum radial expansion ratio of 3.14, the bulk density of 0.106 g/cm3, the compressibility of 56.12 N, and the spring index of 0.892 are identified at the PVA level of 32% and the talc level of 4%, respectively.
HDPE-Clay Nanocomposite Foams Blown with Supercritical CO2
Authors: Lee Yoon Hwan , Park Chul B. , Wang Ki Hyun , Lee Min Hee
Published: August 2005

To investigate the effect of clay particles on the cell morphology of HDPE-clay nanocomposite foams, research on the batch foaming process of HDPE-clay nanocomposites using supercritical CO2 is conducted. This study demonstrates that in comparison with pure HDPE, nanocomposites produce much finer and more uniform cell structures. Additionally, an attempt to produce a nanocellular structure is successfully performed using HDPE-clay nanocomposites.
Drop Weight Impact Test Fracture of Vinyl Ester Composites: Micrographs of Pilot Study
Authors: Ku H. , Cheng Y. M. , Snook C. , Baddeley D.
Published: August 2005

The shrinkage of vinyl ester particulate composites has been reduced by curing the resins under microwave conditions. The reduction in the shrinkage of the resins by microwaves will enable the manufacture of large vinyl ester composite items possible [12-15]. This project is to investigate the difference in impact strength between microwave cured vinyl ester particulate composites and those cured under ambient conditions. Drop weight impact test will be used to achieve the aim of the project [7]. The results show that the difference in the impact strength is minimal [5]. The original contribution of this paper is to view the fractured surface of composites cured under different conditions to find out whether they are the same. If they are the same, it can be deduced that the initial expansion of the composite due to microwave irradiation will not affect the final structure of the composite.
Composites with Inclusions of Negative Bulk Modulus: Extreme Damping and Negative Poisson’s Ratio
Authors: Wang Y. C. , Lakes R. S.
Published: August 2005

The effect of a negative bulk modulus phase in elastic composites is studied. Negative bulk modulus K<0 is shown to be possible in selected unit cells. In isotropic solids, K<0 can be attained when negative Poisson’s ratio is sufficiently small, below the stability limit (for stress control) 1/4 1. Such materials, if used as inclusions, are predicted to be stable with respect to the band formation, even if they are large. Composites with spherical inclusions of negative bulk moduli are shown to exhibit negative Poisson’s ratio and anomalies in composite bulk modulus and Young’s modulus (and in the corresponding mechanical damping) but not in the shear modulus.
Vibration and Damping Analysis of a Sandwich Beam Containing a Viscoelastic Constraining Layer
Authors: Hao Min , Rao Mohan D.
Published: August 2005

Viscoelastic layered systems provide a simple and flexible solution for damping vibration of sheet metal panels. They also help to effectively eliminate noise from resonant structures and surfaces. This article presents an analytical formulation to predict the stiffness and damping of three layered beams with two different viscoelastic materials adjacent to each other. The complex modulus approach is used to model the elastic and shear moduli of the viscoelastic material and closed-form equations are derived for predicting system stiffness and damping. The model is derived for unsymmetrical setups using variational methods. Experiments are conducted on simply supported three-layered beams at different temperatures to validate theoretical results. Similar results are obtained from both the theoretical model and the experiments. A procedure for the optimization of structural and material parameters for maximizing the damping and minimizing the system mass for a given temperature and frequency range is also presented.
Effects of Surface Roughness on High-temperature Oxidation of Carbon-fiber-reinforced Polyimide Composites
Authors: Kung Huang-Kuang
Published: August 2005

In high temperature applications, the oxidation of polymer composites changes their microstructures and degrades their mechanical properties. Both these effects detrimentally affect the service life. Oxidation experiments are time-consuming and cannot be conducted in a laboratory for all layouts of a composite. For this reason, the weight loss of a composite due to oxidation is predicted by the first-order approximation rule of mixtures. Theoretically, the shielding of fibers should slow down the oxidation of a composite than that of a neat resin. However interestingly, the predicted value of oxidation is far lower than that obtained experimentally. In the literature, some researchers have proposed the fiber-matrix interface model to explain the discrepancy while others have believed it is related to the preparation of the surface. This work presents a surface roughness model to clarify the relationship between the high-temperature oxidation and the surface roughness. Predictions concerning high-temperature oxidation are favorably supported by experimental data.
Dividing Countries to Promote Peace: Prospects for Long-Term Success of Partitions
Authors: Tir Jaroslav
Published: August 2005

This article examines the prospects for long-term success of an internally motivated division of a country’s homeland territory - a process known as partition or secession - into rump and secessionist states. The question investigated is why, in the years after the partition, some partitioned countries are able to avoid serious domestic-level violent conflict - operationalized as armed conflict and civil war onset - while others are not. The core logic of the article argues that partition-related factors affect the extent of support for extremist (i.e. conflictual) versus moderate (i.e. accommodative) policies, which in turn determine the prospects for future peace. Aftermaths of all 20th-century partitions are used to examine the related hypotheses. Contrary to the arguments found in much of the extant scholarship, the findings indicate (1) that peaceful partitions are more beneficial than their violent counterparts; (2) that secessionist states are less likely to experience conflict than rump states; and (3) that partitioning for ethnic - as opposed to non-ethnic - reasons does not increase the likelihood of future conflict. Finally, (4) the results reveal a lower than expected degree of support for the common claim that partitioning leads to failure because partitioned countries tend to be ethnically diverse. These findings shed new light on the circumstances under which partitioning may be a useful policymaking tool.