bluuebunny/crossref_metadata_2025 huggingface dataset:
The effects of host genotype, growth rate, and needle age on the distribution of a mutualistic, endophytic fungus in Douglas-fir plantations
Authors: Todd Dennis
Published: February 2008

Two young plantations of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) were examined for the presence of a symptomless endophytic fungus, Meriaparkeri Sherwood-Pike (Hemiphacideaceae). This fungus occurred in the needles of nearly every tree examined, with infection frequencies increasing with the age of the needle. Previous reports have asserted that M. parkeri is a mutualist that produces insecticidal toxins. The maternal parentage of the trees and age of the needles were highly significant predictors of infection frequencies. A detailed examination of two families of trees revealed that infection frequencies differed between sites and were positively correlated with the height of the host. Mutualism and microhabitat effects are discussed.
Comparison of methods for estimating forest overstory cover. I. Observer effects
Authors: Vales David J. , Bunnell Fred L.
Published: February 2008

Four techniques used to estimate forest overstory cover were tested for differences in estimates derived from different observers. No differences in estimates of overstory cover were found between observers for ocular and gimbal sight techniques. Overstory estimates with the moosehorn were inconsistent between observers over all plots. On a plot by plot comparison, observer effects were less pronounced with the moosehorn (differences on 9 of 23 plots, p < 0.05) than with the convex spherical densiometer (differences on 16 of 23 plots, p < 0.05). No technique showed a consistent observer bias. Only the spherical densiometer showed marked interaction between observer and overstory cover (p < 0.05). Results indicate that the more complex methods requiring evaluation of several grids or dots at the same sample point were less consistent between observers. Application of such techniques will benefit from training to standardize observer readings.
Light quantity and quality on the forest floor of pioneer and climax stages in a birch–beech–sugar maple stand
Authors: Messier Christian , Bellefleur Pierre
Published: February 2008

The quantity and quality of solar radiation (300 to 1100 nm) beneath forest canopies were compared on sunny (sunflecks excluded) and cloudy days between the pioneer and climax stages of a birch–beech–sugar maple stand, and among the main species within these two stages of succession. The climax stage (mature canopies) transmits less energy between 300 and 1100 nm and casts smaller red to far red ratios than the pioneer stage (5-year-old canopies) on both sunny and cloudy days. Moreover, the canopies of the main species within each of these two stages of succession do not transmit the same quantity and quality of solar radiation. All these differences are greater on cloudy than sunny days. Leaf transmittance varies among species but this alone does not explain the differences in canopy transmission among these same species. The results are discussed in relation to the ecological significance for the plants growing under birch–beech–sugar maple stands.
Pre- and post-pollination polyhouse environment effects on pollen and seed development in potted Piceaengelmannii grafts
Authors: Ross Stephen D.
Published: February 2008

Potted Piceaengelmannii grafts were moved as reproductive buds began to swell in spring from outdoors into an open, closed, or heated polyethylene-covered house in which day to night temperatures through the completion of pollination averaged 10:5, 14:6, and 24:18 °C. Although increasing polyhouse temperature accelerated pollen shedding by 21 days, this was accomplished by an increased proportion of underdeveloped plus rotted pollen cones (53 to 86%) and decreased yield of pollen per cone (74 to 22 μL). Following pollination grafts were moved from the heated to the open house, and half of those originally in the open and closed houses had their environments switched. Higher polyhouse temperatures during the prepollination period also initially accelerated, and then progressively retarded, the growth of seed cones. Seed cone survival was uniformly high (91–97%) in all treatments. However, cones from the heated/open house treatment were 27% shorter, weighed 59% less, and contained 39 and 88% fewer total and filled seeds, respectively, than cones from the open/open house treatment. Cone development was also adversely affected by heat during the postpollination period. The weight (3–3.2 mg) and germinative capacity (82–95%) of filled seeds were independent of polyhouse treatment. Practical implications for the management of P. engelmannii in indoor-potted orchards are discussed.
Soil compaction effects on Pinustaeda establishment from seed and early growth
Authors: Tuttle C. L. , Golden M. S. , Meldahl R. S.
Published: February 2008

Soil bulk density was related to loblolly pine (Pinustaeda L.) seedling establishment and growth during the first 28 weeks after sowing. Seedling heights were lower when bulk densities exceeded 1.3 Mg m−3 on a sandy clay loam and 1.4 Mg m−3 on a loamy sand. Heights were also lower for bulk densities below 1.2 Mg m−3 on the sandy clay loam soil. Seedling depth of rooting, root weight, and shoot weight were reduced at high bulk densities on both a sandy clay loam and a loamy sand. However, root and shoot weights were also reduced when bulk density fell below 1.3 Mg m−3 on the sandy clay loam. Bulk densities for best seedling growth were 1.3 Mg m−3 for the sandy clay loam and 1.4 Mg m−3 for the loamy sand.
Branch angle in red maple trees
Authors: Bozzuto Lisa M. , Wilson Brayton F.
Published: February 2008

The vertical branch angle 10 cm from the base of 17 branches on 6-year-old red maple (Acerrubrum L.) trees increased as leaves grew out and decreased when leaves abscised, with a net increase in angle. The angle 20 cm from the base of 222 branches on five 32-year-old trees did not increase with increasing branch age. Angles of young branches varied more than 37° within each year class. Angle was significantly related to branch diameter in two of five trees. Leaf weight on the branch was significantly related to branch angle in only one of five trees. Variable amounts of tension wood formed in all branches on the young trees and in 26 of 28 branches sampled from the old trees; 22 of the 45 branches examined had tension wood on both the upper and lower side of the pith. Despite the tendency to increase the angle by bending from leaf weight, long-term increases in angle were (i) obscured by variability in angle within each age class and (ii) apparently counteracted by tension wood maintaining branches at their equilibrium position.
A method of access into the crowns of subcanopy and canopy trees
Authors: McCarthy Brian C.
Published: February 2008

A method of access into the crowns of subcanopy and canopy trees is described. The design consists of a semipermanent wooden pole, erected adjacent to a tree canopy, which is ascended using a portable climbing stand. The technique permits safe canopy access up to 15 m. The advantages are that it can be transported and erected in dense vegetation, it is nondestructive to the habitat and tree crowns, and it is inexpensive and can be used by a single researcher.
The Efficacy of Wet-Cupping in the Treatment of Tension and Migraine Headache
Authors: Ahmadi Alireza , Schwebel David C. , Rezaei Mansour
Published: February 2008

Wet-cupping is an ancient medical technique still used in several contemporary societies, but little empirical study has been devoted to test its efficacy to treat tension and migraine headache. Using a pre-post research design, 70 patients with chronic tension or migraine headache were treated with wet-cupping. Three primary outcome measures were considered at the baseline and 3 months following treatment: headache severity, days of headache per month, and use of medication. Results suggest that, compared to the baseline, mean headache severity decreased by 66% following wet-cupping treatment. Treated patients also experienced the equivalent of 12.6 fewer days of headache per month. We conclude that wet-cupping leads to clinical relevant benefits for primary care patients with headache. Possible mechanisms of wet-cupping's efficacy, as well as directions for future research are discussed.
The Effect of Low versus High Frequency Electrical Acupoint Stimulation on Motor Recovery After Ischemic Stroke by Motor Evoked Potentials Study
Authors: Kim Young Suk , Hong Jin Woo , Na Byung Jo , Park Seong Uk , Jung Woo Sang , Moon Sang Kwan , Park Jung Mi , Ko Chang Nam , Cho Ki Ho , Bae Hyung Sup
Published: February 2008

Electrical acupoint stimulation (EAS) has been used to treat motor dysfunction of stroke patients with reportedly effective results. When we operate EAS treatment, we can modulate the intensity and frequency of stimulation. The purpose of this study is to evaluate the effect of different frequencies in treating motor dysfunction of ischemic stroke patients with EAS. The subjects of this study were 62 ischemic stroke patients with motor dysfunction in Kyunghee oriental medical center. They have been hospitalized after 1 week to 1 month from onset. They were treated with 2 Hz or 120 Hz EAS for 2 weeks, and had motor evoked potentials (MEPs) tests before and after 2 weeks of EAS treatment. We measured latency, central motor conduction time (CMCT) and amplitude of MEPs. After 2 weeks of treatment, we compared MEPs data of the affected side between the 2 Hz group and the 120 Hz group. The 2 Hz group showed more significant improvement than the 120 Hz group in latency, CMCT and amplitude ( p = 0.008, 0.002, 0.002). In the case of the affected side MEPs data divided by normal side MEPs data, the 2 Hz group also showed higher improvement rate than the 120 Hz group in latency, CMCT and amplitude with significant differences ( p = 0.003, 0.000, 0.008). These results suggest that low frequency EAS activates the central motor conduction system better than high frequency EAS, and EAS with low frequency could be more helpful for motor recovery after ischemic stroke than that with high frequency.
Carryover Effects Alter fMRI Statistical Analysis in an Acupuncture Study
Authors: Ho Tsung-Jung , Duann Jeng-Ren , Chen Chun-Ming , Chen Jeon-Hor , Shen Wu-Chung , Lu Tung-Wu , Liao Jan-Ray , Lin Jaung-Geng
Published: February 2008

Carryover effects can contaminate ON/OFF BOLD contrasts designated in an fMRI experiment. Yet, the ON/OFF contrasts are essential to facilitate statistical analysis based on the significance of contrast levels. Here, we conducted an fMRI experiment with acupuncture stimulation applied on ST42 acupoint as well as with tactile stimulation on its skin surface. Experiment consisted of three two-block acupuncture and one two-block tactile fMRI runs. Each block started with 26-sec OFF period followed by either 26-sec needle manipulation in the acupuncture runs or by scratching skin surface with sand paper in the tactile. To test if carryover effects could alter the BOLD contrasts, we analyzed different portions of fMRI data using GLM method. Our results showed analyses on different portions of acupuncture fMRI data gave significantly different results. Statistical parametric maps of group random effects resulted from the analysis on the very first fMRI trial formed the broadest coverage of the active brain areas. BOLD model time course also best explained the adjusted raw time course at peak active voxel ( coefficient of determination = 0.88). Analyses on other portions of fMRI data only selected subset of the active brain areas delineated by the analysis on the very first data trial and the BOLD model only mildly accounted for the adjusted raw time courses. In tactile runs, results were more consistent across analyses. Therefore, in fMRI experiments with strong carryover effects, a single-block experimental design with multiple repetitions, separated by long enough periods of time, should be more suitable to extract task BOLD effects.
Shiunko and Acetylshikonin Promote Reepithelialization, Angiogenesis, and Granulation Tissue Formation in Wounded Skin
Authors: Lu Pao-Ju , Yang Cheng , Lin Ching-Nan , Li Chien-Feng , Chu Chin-Chen , Wang Jhi-Joung , Chen Jen-Yin
Published: February 2008

Shiunko is a traditional botanic formula (ointment) used clinically for treating wounded skin. The aim of the present study was to compare the effects of Shiunko and acetylshikonin, and its active ingredient, with those of gentamicin and silver sulfadiazine ointments, two disinfectants for wound healing. Wounds were cut in the backs of Sprague-Dawley rats. Different bacterial inoculations (Pseudomonas aeruginosa and Staphylococcus aureus) and treatments (Shiunko, acetylshikonin, gentamicin, silver sulfadiazine, and vehicle ointments) were used to treat these wounds. We found that rats treated with Shiunko and acetylshikonin on both the sterilized and infected wounds showed higher rates of reepithelialization than those treated with the other ointments (p < 0.05) during a 7-day observation. In the histological study, rats treated with Shiunko and acetylshikonin on both the sterilized and infected wounds showed greater reepithelialization, angiogenesis, and granulation tissue formation than rats treated with the other ointments (p < 0.05) on day 5 after the wounds had been sutured. Differences between rats treated with Shiunko and acetylshikonin ointments were not statistically significant. In conclusion, topically applying Shiunko and acetylshikonin on wounded skin promoted wound healing. Both ointments were effective on sterilized and infected wounds.
Effects ofRadix scutellariaeandRhizoma atractylodison LPS-Induced Abortion and the Uterine IL-10 Contents in Mice
Authors: Zhong Xiu-Hui , Shi Wan-Yu , Ma Ai-Tuan , Gong Xin-Cheng , Zhai Xiang-He , Zhang Tie , Wang Xiao-Dan
Published: February 2008

In the present study, lipopolysaccharide (LPS) was injected i.v. via the tail vein (0.1 μg per mouse) to induce abortion (embryo resorption) in Kunming mice. The interleukin 10 (IL-10) contents in the uterus were assayed by ELISA. The results revealed that the IL-10 level was significantly decreased in the LPS-induced abortion group of mice compared to the controls. Use of Pentoxifylline (PXF), or a combination of Radix scutellariae and Rhizoma atractylodis reversed the LPS effects: bringing down the fetal resorption rate, and increasing the IL-10 level significantly. The study indicates that the anti-abortive effects of PXF and the combination of Radix scutellariae and Rhizoma atractylodis are closely related to up-regulation of the Th 2 cytokine IL-10 at the maternal fetal interface.
Hypouricemic Effects of Phenylpropanoid Glycosides Acteoside ofScrophularia ningpoensison Serum Uric Acid Levels in Potassium Oxonate-Pretreated Mice
Authors: Huang Cai Guo , Shang Yan Jun , Zhang Jun , Zhang Jian Rong , Li Wen Jie , Jiao Bin Hua
Published: February 2008

Phenylpropanoid glycoside acteoside was extracted from the traditional Chinese medicine Scrophularia ningpoenis Hemsl. In the present study, we investigated the effects of acteoside administration on serum uric acid levels in mice rendered hyperuricemic with the uricase inhibitor potassium oxonate. When administered orally for 3 days at doses of 50, 100 and 150 mg/kg, acteoside reduced serum uric acid levels by 15.2, 23.8 and 33.1%, respectively, relative to vehicle-treated hyperuricemic mice. Importantly, in non-hyperuricemic mice, the serum uric acid levels were not affected by acetoside treatment. Acteoside also inhibited mouse liver xanthine dehydrogenase XDH and xanthine oxidase XO activity at all three doses. These results suggest that the hypouricemic action of acteoside may be attributable to its inhibition of XDH/XO activity.
LATTICES AND PERIODIC GEODESICS IN PSEUDORIEMANNIAN 2-STEP NILPOTENT LIE GROUPS
Authors: CORDERO LUIS A. , PARKER PHILLIP E.
Published: February 2008

We give a basic treatment of lattices Γ in these groups. Certain tori TF and TB provide the model fiber and the base for a submersion of Γ\N. This submersion may not be pseudoriemannian in the usual sense, because the tori may be degenerate. We then begin the study of periodic geodesics in these compact nilmanifolds, obtaining a complete calculation of the period spectrum of certain flat spaces.
AN INTRODUCTION TO QUANTUM GRAVITY
Authors: DEWITT BRYCE S. , ESPOSITO GIAMPIERO
Published: February 2008

After an overview of the physical motivations for studying quantum gravity, we reprint THE FORMAL STRUCTURE OF QUANTUM GRAVITY, i.e. the 1978 Cargèse Lectures in Levy & Deser (1979): Recent Developments in Gravitation pp. 275–322 by Professor B. S. DeWitt, with kind permission of Springer Science and Business Media. The reader is therefore introduced, in a pedagogical way, to the functional integral quantization of gravitation and Yang–Mills theory. It is hoped that such a paper will remain useful for all lecturers or Ph.D. students who face the task of introducing (resp. learning) some basic concepts in quantum gravity in a relatively short time. In the second part, we outline selected topics such as the braneworld picture with the same covariant formalism of the first part, and spectral asymptotics of Euclidean quantum gravity with diffeomorphism-invariant boundary conditions. The latter might have implications for singularity avoidance in quantum cosmology.
Dynamics of single potassium channel proteins in the plasma membrane of migrating cells
Authors: Nechyporuk-Zloy Volodymyr , Dieterich Peter , Oberleithner Hans , Stock Christian , Schwab Albrecht
Published: February 2008

Cell migration is an important physiological process among others controlled by ion channel activity. Calcium-activated potassium channels (KCa3.1) are required for optimal cell migration. Previously, we identified single human (h)KCa3.1 channel proteins in the plasma membrane by means of quantum dot (QD) labeling. In the present study, we tracked single-channel proteins during migration to classify their dynamics in the plasma membrane of MDCK-F cells. Single hKCa3.1 channels were visualized with QD- or Alexa488-conjugated antibodies and tracked at the basal cell membrane using time-lapse total internal reflection fluorescence (TIRF) microscopy. Analysis of the trajectories allowed the classification of channel dynamics. Channel tracks were compared with those of free QD-conjugated antibodies. The size of the label has a pronounced effect on hKCa3.1 channel diffusion. QD-labeled channels have a (sub)diffusion coefficient DQDbound = 0.067 μm2/sα, whereas that of Alexa488-labeled channels is DAlexa = 0.139 μm2/s. Free QD-conjugated antibodies move much faster: DQDfree = 2.163 μm2/sα. Plotting the mean squared distances (msd) covered by hKCa3.1 channels as a function of time points to the mode of diffusion. Alexa488-labeled channels diffuse normally, whereas the QD-label renders hKCa3.1 channel diffusion anomalous. Free QD-labeled antibodies also diffuse anomalously. Hence, QDs slow down diffusion of hKCa3.1 channels and change the mode of diffusion. These results, referring to the role of label size and properties of the extracellular environment, suggest that the pericellular glycocalyx has an important impact on labels used for single molecule tracking. Thus tracking fluorescent particles within the glycocalyx opens up a possibility to characterize the pericellular nanoenvironment.
Expression and function of the rat vesicular monoamine transporter 2
Authors: Adam Yoav , Edwards Robert H. , Schuldiner Shimon
Published: February 2008

The vesicular monoamine transporters (VMATs) are essential proteins, involved in the storage of monoamines in the central nervous system and in endocrine cells, in a process that involves exchange of 2H+ with one substrate molecule. The VMATs interact with various native substrates and clinically relevant drugs and display the pharmacological profile of multidrug transporters. Vesicular transporters suffer from a lack of biochemical and structural data due to the difficulties in their expression. In this work we present the high-level expression of rat VMAT2 (rVMAT2) in a stable a human embryonic kidney cell line (HEK293), generated using the resistance to the neurotoxin 1-methyl-4-phenylpyridinium (MPP+) conferred by the protein. In addition, we describe novel procedures for the solubilization and purification of active protein, and its reconstitution into proteoliposomes. The partially purified protein in detergent binds the inhibitor tetrabenazine and, after reconstitution, displays high levels of ΔμH+-driven electrogenic transport of serotonin. The reconstituted purified rVMAT2 has wild-type affinity for serotonin, and its turnover rate is ∼0.4 substrate molecule/s.
Long-term hypoxia modulates expression of key genes regulating adipose function in the late-gestation ovine fetus
Authors: Myers Dean A. , Hanson Krista , Mlynarczyk Malgorzata , Kaushal Kanchan M. , Ducsay Charles A.
Published: February 2008

A major function of abdominal adipose in the newborn is nonshivering thermogenesis. Uncoupling protein (UCP) UCP1 and UCP2 play major roles in thermogenesis. The present study tested the hypothesis that long-term hypoxia (LTH) modulates expression of UCP1 and UCP2, and key genes regulating expression of these genes in the late-gestation ovine fetus. Ewes were maintained at high altitude (3,820 m) from 30 to 138 days gestation (dG); perirenal adipose tissue was collected from LTH and age-matched, normoxic control fetuses at 139–141 dG. Quantitative real-time PCR was used to analyze mRNA for UCP1, UCP2, 11β hydroxysteroid dehydrogenase type 1 (HSD11B1) and 2 (HSD11B2), glucocorticoid receptor (GR), β3 adrenergic receptor (β3AR), deiodinase type 1 (DIO1) and DIO2, peroxisome proliferator activated receptor (PPAR) α and γ and PPARγ coactivator 1 (PGC1α). Concentrations of mRNA for UCP1, HSD11B1, PPARγ, PGC1, DIO1, and DIO2 were significantly higher in perirenal adipose of LTH compared with control fetuses, while mRNA for HSD11B2, GR, or PPARα in perirenal adipose did not differ between control and LTH fetuses. The increased expression of UCP1 is likely an adaptive response to LTH, assuring adequate thermogenesis in the event of birth under oxygen-limiting conditions. Because both glucocorticoids and thyroid hormone regulate UCP1 expression, the increase in HSD11B1, DIO1, and DIO2 implicate increased adipose capacity for local synthesis of these hormones. PPARγ and its coactivator may provide an underlying mechanism via which LTH alters development of the fetal adipocyte. These findings have important implications regarding fetal/neonatal adipose tissue function in response to LTH.
Preeclamptic sera induce nephrin shedding from podocytes through endothelin-1 release by endothelial glomerular cells
Authors: Collino Federica , Bussolati Benedetta , Gerbaudo Elisa , Marozio Luca , Pelissetto Simona , Benedetto Chiara , Camussi Giovanni
Published: February 2008

In preeclampsia (PE), proteinuria has been associated with a reduced expression of nephrin by podocytes. In the present study, we investigated in vitro on human cultured podocytes the mechanism responsible for nephrin loss in PE. Sera from patients with PE did not directly downregulate the expression of nephrin. In contrast, conditioned medium obtained from glomerular endothelial cells incubated with PE sera induced loss of nephrin and synaptopodin, but not of podocin, from podocytes. Nephrin loss was related to a rapid shedding of the protein from the cell surface due to cleavage of its extracellular domain by proteases and to cytoskeleton redistribution. The absence of nephrin mRNA downregulation together with nephrin reexpression within 24 h confirm that the loss of nephrin was not related to a reduced synthesis. Studies with an endothelin-1 (ET-1) receptor antagonist that abrogated the loss of nephrin triggered by glomerular endothelial conditioned medium of PE sera indicated that ET-1 was the main effector of nephrin loss. Indeed, ET-1 was synthesized and released from glomerular endothelial cells when incubated with PE sera, and recombinant ET-1 triggered nephrin shedding from podocytes. Moreover, VEGF blockade induced ET-1 release from endothelial cells, and in turn the conditioned medium obtained triggered nephrin loss. In conclusion, the present study identifies a potential mechanism of nephrin loss in PE that may link endothelial injury with enhanced glomerular permeability.
Transcriptional control of terminal nephron differentiation
Authors: El-Dahr Samir S. , Aboudehen Karam , Saifudeen Zubaida
Published: February 2008

Terminal differentiation of epithelial cells into more specialized cell types is a critical step in organogenesis. Throughout the process of terminal differentiation, epithelial progenitors acquire or upregulate expression of renal function genes and cease to proliferate, while expression of embryonic genes is repressed. This exquisite coordination of gene expression is accomplished by signaling networks and transcription factors which couple the external environment with the new functional demands of the cell. While there has been much progress in understanding the early steps involved in renal epithelial cell differentiation, a major gap remains in our knowledge of the factors that control the steps of terminal differentiation. A number of signaling molecules and transcription factors have been recently implicated in determining segmental nephron identity and functional differentiation. While some of these factors (the p53 gene family, hepatocyte nuclear factor-1β) promote the terminal epithelial differentiation fate, others (Notch, Brn-1, IRX, KLF4, and Foxi1) tend to regulate differentiation of specific nephron segments and individual cell types. This review summarizes current knowledge related to these transcription factors and discusses how diverse cellular signals are integrated to generate a transcriptional output during the process of terminal differentiation. Since these transcriptional processes are accompanied by profound changes in nuclear chromatin structure involving the genes responsible for creating and maintaining the differentiated cell phenotype, future studies should focus on identifying the nature of these epigenetic events and factors, how they are regulated temporally and spatially, and the chromatin environment they eventually reside in.
Role of collateral paths in long-range diffusion in lungs
Authors: Bartel Seth-Emil T. , Haywood Susan E. , Woods Jason C. , Chang Yulin V. , Menard Christopher , Yablonskiy Dmitriy A. , Gierada David S. , Conradi Mark S.
Published: February 2008

The long-range apparent diffusion coefficient (LRADC) of 3He gas in lungs, measured over times of several seconds and distances of 1–3 cm, probes the connections between the airways. Previous work has shown the LRADC to be small in health and substantially elevated in emphysema, reflecting tissue destruction, which is known to create collateral pathways. To better understand what controls LRADC, we report computer simulations and measurements of 3He gas diffusion in healthy lungs. The lung is generated with a random algorithm using well-defined rules, yielding a three-dimensional set of nodes or junctions, each connected by airways to one parent node and two daughters; airway dimensions are taken from published values. Spin magnetization in the simulated lung is modulated sinusoidally, and the diffusion equation is solved to 1,000 s. The modulated magnetization decays with a time constant corresponding to an LRADC of ∼0.001 cm2/s, which is smaller by a factor of ∼20 than the values in healthy lungs measured here and previously in vivo and in explanted lungs. It appears that collateral gas pathways, not present in the simulations, are functional in healthy lungs; they provide additional and more direct routes for long-range motion than the canonical airway tree. This is surprising, inasmuch as collateral ventilation is believed to be physiologically insignificant in healthy lungs. We discuss the effect on LRADC of small collateral connections through airway walls and rule out other possible mechanisms. The role of collateral paths is supported by measurements of smaller LRADC in pigs, where collateral ventilation is known to be smaller.
Sensitivity of Inferior Colliculus Neurons to Interaural Time Differences in the Envelope Versus the Fine Structure With Bilateral Cochlear Implants
Authors: Smith Zachary M. , Delgutte Bertrand
Published: February 2008

Bilateral cochlear implantation seeks to improve hearing by taking advantage of the binaural processing of the central auditory system. Cochlear implants typically encode sound in each spectral channel by amplitude modulating (AM) a fixed-rate pulse train, thus interaural time differences (ITD) are only delivered in the envelope. We investigated the ITD sensitivity of inferior colliculus (IC) neurons with sinusoidally AM pulse trains. ITD was introduced independently to the AM and/or carrier pulses to measure the relative efficacy of envelope and fine structure for delivering ITD information. We found that many IC cells are sensitive to ITD in both the envelope (ITDenv) and fine structure (ITDfs) for appropriate modulation frequencies and carrier rates. ITDenv sensitivity was generally similar to that seen in normal-hearing animals with AM tones. ITDenv tuning generally improved with increasing modulation frequency up to the maximum modulation frequency that elicited a sustained response in a neuron (tested ≤160 Hz). ITDfs sensitivity was present in about half the neurons for 1,000 pulse/s (pps) carriers and was nonexistent at 5,000 pps. The neurons that were sensitive to ITDfs at 1,000 pps were those that showed the best ITD sensitivity to low-rate pulse trains. Overall, the best ITD sensitivity was found for ITD contained in the fine structure of a moderate rate AM pulse train (1,000 pps). These results suggest that the interaural timing of current pulses should be accurately controlled in a bilateral cochlear implant processing strategy that provides salient ITD cues.
cGMP Activates a pH-Sensitive Leak K+ Current in the Presumed Cholinergic Neuron of Basal Forebrain
Authors: Toyoda Hiroki , Saito Mitsuru , Sato Hajime , Dempo Yoshie , Ohashi Atsuko , Hirai Toshihiro , Maeda Yoshinobu , Kaneko Takeshi , Kang Youngnam
Published: February 2008

In an earlier study, we demonstrated that nitric oxide (NO) causes the long-lasting membrane hyperpolarization in the presumed basal forebrain cholinergic (BFC) neurons by cGMP–PKG-dependent activation of leak K+ currents in slice preparations. In the present study, we investigated the ionic mechanisms underlying the long-lasting membrane hyperpolarization with special interest in the pH sensitivity because 8-Br-cGMP–induced K+ current displayed Goldman–Hodgkin–Katz rectification characteristic of TWIK-related acid-sensitive K+ (TASK) channels. When examined with the ramp command pulse depolarizing from −130 to −40 mV, the presumed BFC neurons displayed a pH-sensitive leak K+ current that was larger in response to pH decrease from 8.3 to 7.3 than in response to pH decrease from 7.3 to 6.3. This K+ current was similar to TASK1 current in its pH sensitivity, whereas it was highly sensitive to Ba2+, unlike TASK1 current. The 8-Br-cGMP–induced K+ currents in the presumed BFC neurons were almost completely inhibited by lowering external pH to 6.3 as well as by bath application of 100 μM Ba2+, consistent with the nature of the leak K+ current expressed in the presumed BFC neurons. After 8-Br-cGMP application, the K+ current obtained by pH decrease from 7.3 to 6.3 was larger than that obtained by pH decrease from pH 8.3 to 7.3, contrary to the case seen in the control condition. These observations strongly suggest that 8-Br-cGMP activates a pH- and Ba2+-sensitive leak K+ current expressed in the presumed BFC neurons by modulating its pH sensitivity.
Interactions With Compliant Loads Alter Stretch Reflex Gains But Not Intermuscular Coordination
Authors: Perreault Eric J. , Chen Kuifu , Trumbower Randy D. , Lewis Gwyn
Published: February 2008

The human motor system regulates arm mechanics to produce stable postures during interactions with different physical environments. This occurs partly via involuntary mechanisms, including stretch reflexes. Previous single-joint studies demonstrated enhanced reflex sensitivity during interactions with compliant environments, suggesting reflex gain increases to enhance limb stability when that stability is not provided by the environment. This study examined whether similar changes in reflex gain are present throughout the limb following perturbations that simultaneously influence multiple joints. Furthermore, we investigated whether any observed modulation was accompanied by task-specific changes in reflex coordination across muscles, a question that cannot be addressed using single-joint perturbations. Reflexes were elicited during the maintenance of posture by perturbing the arm with a three degrees of freedom robot, configured to have isotropic stiffness of either 10 N/m (compliant) or 10 kN/m (stiff). Perturbation characteristics were matched in both environments. Reflex magnitude was quantified by the average rectified electromyogram, recorded from eight muscles crossing the elbow and shoulder. Reflex coordination was assessed using independent components analysis to compare reflex activation patterns during interactions with stiff and compliant environments. Stretch reflex sensitivity increased significantly in all muscles during interactions with the compliant environment and these changes were not due to changes in background muscle activity. However, there was no significant difference in the reflex coordination patterns observed during interactions with the stiff and compliant environments. These results suggest that reflex modulation occurred through altered use of fixed muscle coordination patterns rather than through a change in reflex coordination.
Effects of Visual and Auditory Feedback on Sensorimotor Circuits in the Basal Ganglia
Authors: Prodoehl Janey , Yu Hong , Wasson Pooja , Corcos Daniel M. , Vaillancourt David E.
Published: February 2008

Previous work using visual feedback has identified two distinct sensorimotor circuits in the basal ganglia (BG): one that scaled with the duration of force and one that scaled with the rate of change of force. The present study compared functional MRI signal changes in the BG during a grip force task using either visual or auditory feedback to determine whether the BG nuclei process auditory and visual feedback similarly. We confirmed the same two sensorimotor circuits in the BG. Activation in the striatum and external globus pallidus (GPe) scaled linearly with the duration of force under visual and auditory feedback conditions, with similar slopes and intercepts across feedback type. The pattern of signal change for the internal globus pallidus (GPi) and subthalamic nucleus (STN) was nonlinear and parameters of the exponential function were altered by feedback type. Specifically, GPi and STN activation decreased exponentially with the rate of change of force. The rate constant and asymptote of the exponential functions for GPi and STN were greater during auditory than visual feedback. In a comparison of the BOLD signal between BG regions, GPe had the highest percentage of variance accounted for and this effect was preserved for both feedback types. These new findings suggest that neuronal activity of specific BG nuclei is affected by whether the feedback is derived from visual or auditory inputs. Also, the data are consistent with the hypothesis that the GPe has a high level of information convergence from other BG nuclei, which is preserved across different sensory feedback modalities.
Differential Modulation of Neural Network and Pacemaker Activity Underlying Eupnea and Sigh-Breathing Activities
Authors: Tryba Andrew K. , Peña Fernando , Lieske Steven P. , Viemari Jean-Charles , Thoby-Brisson Muriel , Ramirez Jan-Marino
Published: February 2008

Many networks generate distinct rhythms with multiple frequency and amplitude characteristics. The respiratory network in the pre-Bötzinger complex (pre-Böt) generates both the low-frequency, large-amplitude sigh rhythm and a faster, smaller-amplitude eupneic rhythm. Could the same set of pacemakers generate both rhythms? Here we used an in vitro respiratory brainslice preparation. We describe a subset of synaptically isolated pacemakers that spontaneously generate two distinct bursting patterns. These two patterns resemble network activity including sigh-like bursts that occur at low frequencies and have large amplitudes and eupneic-like bursts with higher frequency and smaller amplitudes. Cholinergic neuromodulation altered the network and pacemaker bursting: fictive sigh frequency is increased dramatically, whereas fictive eupneic frequency is drastically lowered. The data suggest that timing and amplitude characteristics of fictive eupneic and sigh rhythms are set by the same set of pacemakers that are tuned by changes in the neuromodulatory state.
Geometric Particle Swarm Optimization
Authors: Moraglio Alberto , Di Chio Cecilia , Togelius Julian , Poli Riccardo
Published: February 2008

Using a geometric framework for the interpretation of crossover of recent introduction, we show an intimate connection between particle swarm optimisation (PSO) and evolutionary algorithms. This connection enables us to generalise PSO to virtually any solution representation in a natural and straightforward way. The new Geometric PSO (GPSO) applies naturally to both continuous and combinatorial spaces. We demonstrate this for the cases of Euclidean, Manhattan and Hamming spaces and report extensive experimental results. We also demonstrate the applicability of GPSO to more challenging combinatorial spaces. The Sudoku puzzle is a perfect candidate to test new algorithmic ideas because it is entertaining and instructive as well as being a nontrivial constrained combinatorial problem. We apply GPSO to solve the Sudoku puzzle.
Convergence Analysis of a Fourier‐Based Solution Method of the Laplace Equation for a Model of Magnetic Recording
Authors: Fleming John L.
Published: February 2008

When engineers model the magnetostatic fields applied to recording heads of computer hard drives due to a magnetic recording medium, the solution of Laplace′s equation must be found. A popular solution method is based on Fourier analysis. However, due to the geometry of the read head model, an interesting mathematical problem arises. The coefficients for the Fourier series solution of the desired magnetic potential satisfy an infinite system of linear equations. In practice, the infinite system is truncated to a finite system with little consideration for the effect this truncation has on the solution. The paper will provide a proper understanding of the underlying problem and a formal analysis of the effect of truncation.
The Cold Contact Method as a Simple Drug Interaction Detection System
Authors: Nugrahani Ilma , Asyarie Sukmadjaja , Soewandhi Sundani Nurono , Ibrahim Slamet
Published: February 2008

The physical interaction between 2 substances frequently occurs along the mixing and manufacturing of solid drug dosage forms. The physical interaction is generally based on coarrangement of crystal lattice of drug combination. The cold contact method has been developed as a simple technique to detect physical interaction between 2 drugs. This method is performed by observing new habits of cocrystal that appear on contact area of crystallization by polarization microscope and characterize this cocrystal behavior by melting point determination. Has been evaluated by DSC, this method is proved suitable to identify eutecticum interaction of pseudoephedrine HCl-acetaminophen, peritecticum interaction of methampyrone-phenylbutazon, and solid solution interaction of amoxicillin-clavulanate, respectively.
Early Expression of FcγRI (CD64) on Monocytes of Cardiac Surgical Patients and Higher Density of Monocyte Anti‐Inflammatory Scavenger CD163 Receptor in “On‐Pump” Patients
Authors: Kolackova Martina , Kudlova Manuela , Kunes Pavel , Lonsky Vladimir , Mandak Jiri , Andrys Ctirad , Jankovicova Karolina , Krejsek Jan
Published: February 2008

Objective.
Activation of innate immunity cells is inseparably linked to cardiac surgical operation. The aim of this study was to assess the kinetics in the expression of receptor for Fc part of IgG, FcγRI (CD64), and scavenger receptor CD163 on peripheral blood cells of cardiac surgical patients and to examine the effect of cardiac bypass as a separable influence on the systemic acute inflammatory response.
Methods.
Forty patients, twenty in each group, were randomly assigned to CABG surgery performed either with “on‐pump” or without “off‐pump” cardiopulmonary bypass. Standardized quantitative flow cytometry method was used to determine the expression of surface markers.
Results.
The density of CD64 molecule on monocytes reached maximum on the 1st postoperative day (P < .001) whereas the peak for CD64 molecule expression on granulocytes was postponed to the 3rd
postoperative day (P < .001). The expression of CD163 scavenger molecule on monocytes reached maximum on the 1st postoperative day
(P < .001). The density of CD163 molecule on monocytes on the 1st postoperative day is
significantly higher in “on‐pump” patients in comparison
with “off‐pump” patients (P < .001).
Conclusion.
In cardiac surgical patients the expression of activation marker FcγR1 (CD64) on monocytes is increased earlier in comparison with granulocytes in
both “on‐pump” and “off‐pump” patients. The expression of scavenger
molecule CD163 on monocytes is significantly higher in “on‐pump” patients.
Peptide Mimicrying Between SARS Coronavirus Spike Protein and Human Proteins Reacts with SARS Patient Serum
Authors: Hwa K.-Y. , Lin W. M. , Hou Y.-I. , Yeh T.-M.
Published: February 2008

Molecular mimicry, defined as similar structures shared by molecules from dissimilar genes or proteins, is a general strategy used by pathogens to infect host cells. Severe acute respiratory syndrome (SARS) is a new human respiratory infectious disease caused by SARS coronavirus (SARS‐CoV). The spike (S) protein of SARS‐CoV plays an important role in the virus entry into a cell. In this study, eleven synthetic peptides from the S protein were selected based on its sequence homology with human proteins. Two of the peptides D07 (residues 927–937) and D08 (residues 942–951) were recognized by the sera of SARS patients. Murine hyperimmune sera against these peptides bound to proteins of human lung epithelial cells A549. Another peptide D10 (residues 490–502) stimulated A549 to proliferate and secrete IL‐8. The present results suggest that the selected S protein regions, which share sequence homology with human proteins, may play important roles in SARS‐CoV infection.
Bootstrap and Order Statistics for Quantifying Thermal-Hydraulic Code Uncertainties in the Estimation of Safety Margins
Authors: Zio Enrico , Di Maio Francesco
Published: February 2008

In the present work, the uncertainties affecting the safety margins estimated from thermal-hydraulic code calculations are captured quantitatively by resorting to the order statistics and the bootstrap technique. The proposed framework of analysis is applied to the estimation of the safety margin, with its confidence interval, of the maximum fuel cladding temperature reached during a complete group distribution blockage scenario in a RBMK-1500 nuclear reactor.
Green′s‐Like Relations on Algebras and Varieties
Authors: Denecke K. , Wismath S. L.
Published: February 2008

There are five equivalence relations known as Green′s relations definable on any
semigroup or monoid, that is, on any algebra with a binary operation which is
associative. In this paper, we examine whether Green′s relations can be defined
on algebras of any type τ.
Some sort of (super‐)associativity is needed for such definitions to work, and we consider algebras
which are clones of terms of type τ, where the clone axioms including superassociativity hold. This allows us to define
for any variety V of type τ two Green′s‐like
relations ℒV and ℛV on the term clone of type τ. We prove
a number of properties of these two relations, and describe their behaviour when
V is a variety of semigroups.
Shared Reproductive State Enhances Female Associations in Dolphins
Authors: Möller Luciana M. , Harcourt Robert G.
Published: February 2008

Female bottlenose dolphins (genusTursiops) usually associate at moderate level with other females within social clusters called bands or cliques. It has been suggested that reproductive state may play the predominant role in determining associations within femaleT. truncatusbands. Here, we test the hypothesis that reproductive state correlates with associations of female Indo-Pacific bottlenose dolphins (T. aduncus). We found that females in similar reproductive state, which included females from late pregnancy to the first year of their calves' life or females from early pregnancy to their calves' newborn period, had higher-association coefficients with each other than they did with females in different reproductive states (females with older calves or without calves). This was observed both within and across social clusters suggesting that reproductive state, at least for pregnant females and those with young calves, plays an important role in determining who to associate with. However, a female's most frequent associate was not always with another in similar reproductive state. We suggest that several factors, including reproductive state, may be of importance in determining associations of female bottlenose dolphins.
Subordination Properties for Certain Analytic Functions
Authors: Attiya A. A. , Cho Nak Eun , Kutbi M. A.
Published: February 2008

The purpose of the present paper is to derive a subordination result for functions in the class of normalized analytic functions in the
open unit disk . A number of interesting applications of the subordination result are also considered.
A Simplified Recombinant PSO
Authors: Bratton Dan , Blackwell Tim
Published: February 2008

Simplified forms of the particle swarm algorithm are very beneficial in contributing to understanding how a particle swarm optimization (PSO) swarm functions. One of these forms, PSO with discrete recombination, is extended and analyzed, demonstrating not just improvements in performance relative to a standard PSO algorithm, but also significantly different behavior, namely, a reduction in bursting patterns due to the removal of stochastic components from the update equations.
Deterministic Analysis of Natural Circulation Events at the Ignalina NPP
Authors: Kaliatka Algirdas , Uspuras Eugenijus , Vileiniskis Virginijus
Published: February 2008

Eight main circulation pumps (MCPs) are employed for the cooling of water forced circulation through the RBMK-1500 reactor at the Ignalina nuclear power plant (NPP). These pumps are joined into groups of four pumps each (three for normal operation and one on standby). In the case of all MCPs trip, the reactor shutdown system is activated due to decrease of coolant flow rate. At the same time, after the pump trip, the coolant to the reactor fuel channels during the first few seconds is supplied by pump coastdown. Later, the reactor is cooled by natural circulation. The main question arises whether this coolant flow rate is sufficient to remove the decay heat from the reactor core. This paper presents the investigation of all MCPs trip events at the Ignalina NPP by employing best estimate code RELAP5 and methodology of uncertainty and sensitivity analysis.
Statistical Analysis of Twin Populations using Dissimilarity Measurements in Hippocampus Shape Space
Authors: Park Youngser , Priebe Carey E. , Miller Michael I. , Mohan Nikhil R. , Botteron Kelly N.
Published: February 2008

By analyzing interpoint comparisons, we obtain significant results describing the
relationship in “hippocampus shape space” of clinically depressed, high‐risk, and control
populations. In particular, our analysis demonstrates that the high‐risk population
is closer in shape space to the control population than to the clinically depressed population.