bluuebunny/crossref_metadata_2025 huggingface dataset:
CORRESPONDENCE BETWEEN PHYLOGENY AND MORPHOLOGY OF SNOWELLA SPP. AND WORONICHINIA NAEGELIANA, CYANOBACTERIA COMMONLY OCCURRING IN LAKES1
Authors: Rajaniemi‐Wacklin Pirjo , Rantala Anne , Mugnai Maria. A. , Turicchia Silvia , Ventura Stefano , Komárková Jarka , Lepistö Liisa , Sivonen Kaarina
Published: January 2006

In this study, the first reported isolates of the genera Snowella and Woronichinia were characterized by 16S rRNA gene sequencing and morphological analysis. Phylogenetic studies and sequences for these genera were not available previously. By botanical criteria, the five isolated strains were identified as Snowella litoralis (Häyrén) Komárek et Hindák Snowella rosea (Snow) Elenkin and Woronichinia naegeliana (Unger) Elenkin. This study underlines the identification of freshly isolated cultures, since the Snowella strains lost the colony structure and were not identifiable after extended laboratory cultivation. In the 16S rRNA gene analysis, the Snowella strains formed a monophyletic cluster, which was most closely related to the Woronichinia strain. Thus, our results show that the morphology of the genera Snowella and Woronichinia was in congruence with their phylogeny, and their phylogeny seems to support the traditional botanical classification of these genera. Furthermore, the genera Snowella and Woronichinia occurred commonly and might occasionally be the most abundant cyanobacterial taxa in mainly oligotrophic and mesotrophic Finnish lakes. Woronichinia occurred frequently and also formed blooms in eutrophic Czech reservoirs.
NUCLEAR FEATURES AND EFFECT OF NUTRIENTS ON GYMNODINIUM CATENATUM (DINOPHYCEAE) SEXUAL STAGES1
Authors: Figueroa Rosa Isabel , Bravo Isabel , Garcés Esther , Ramilo Isabel
Published: January 2006

Gymnodinium catenatum Graham is an unarmored, cyst‐forming dinoflagellate species responsible for outbreaks of paralytic shellfish poisoning. The nuclear development of the cells during the sexual cycle and the effect of different nitrate and phosphate external levels on sexual stages were studied. Nuclear fusion of gametes occurred before or at the same time as cytoplasmic fusion. During this process, either both nuclei migrated to a central area in the sulcal region, or only one of them migrated to the other nucleus. The motile and longitudinally biflagellated zygote presented a large, pear‐shaped nucleus, and either divided or encysted. Planozygotes and germlings underwent similar division processes, which suggested an uncoordinated meiosis in both encysting and non‐encysting zygotes. Encystment in culture was greater under low nitrate and phosphate limitation (L/15) than when only one or neither of these nutrients were added (L‐N, L‐P, and ‐N‐P). However, planozygotes individually monitored achieved the maximum encystment (40%) in a medium with no phosphate or nitrate added (‐N‐P), while most of them divided (70%–90%) in replete (L1) or half‐replete (L‐N and L‐P) media. Low levels of nitrate in the medium of cyst formation promoted a deficient development of the cyst wall. On the other hand, low phosphate levels in the medium of germination prevented both planozygote and germling division and lowered the final germination frequencies of cysts. The minimum dormancy, with an average value of 13.7±5.5 days, was not affected by any of the nutritional conditions studied.
ABUNDANCE OF A NOVEL DINOFLAGELLATE PHYLOTYPE IN THE ROSS SEA, ANTARCTICA1
Authors: Gast Rebecca J. , Moran Dawn M. , Beaudoin David J. , Blythe Jonathan N. , Dennett Mark R. , Caron David A.
Published: January 2006

The biodiversity of protistan assemblages present in microhabitats of the Ross Sea, Antarctica, was examined using molecular biological methods to obtain a greater understanding of the genetic diversity present. Sequencing of 18S clone libraries indicated genetically diverse collections of organisms in the water column, ice, and meltwater layer (slush), but a single small subunit ribosomal DNA (srDNA) sequence type dominated clone libraries (>30%) from seawater and slush samples taken within the ice pack of this ecosystem. The BLAST searches indicated that this dominant clone was derived from a dinoflagellate, and that it shared sequence similarity (97.6%–98.3%) with both Karenia and Karlodinium species. Phylogenetic analyses based on small subunit ribosomal gene sequences supported its placement as a sister group to these taxa, and suggested that it represented a novel genus. The dinoflagellate was successfully recovered in culture, and morphological analyses have shown that it contains chloroplasts, is gymnodinoid, appears not to have thecal plates, and has an apical groove and sulcal structure that confirm its placement as a relative of the Karenia/Karlodinium group. The abundance of this phylotype in natural samples was confirmed by quantitative PCR analyses of water and slush communities, and suggests that this dinoflagellate can be a major constituent of the protistan assemblages of some Antarctic microhabitats of the Ross Sea.
REVERSE TRANSCRIPTION PCR AMPLIFICATION OF CYANOBACTERIAL SYMBIONT 16S RRNA SEQUENCES FROM SINGLE NON‐PHOTOSYNTHETIC EUKARYOTIC MARINE PLANKTONIC HOST CELLS1
Authors: Foster Rachel A. , Collier Jackie L. , Carpenter Edward J.
Published: January 2006

A reverse transcription‐polymerase chain reaction (RT‐PCR) method was developed for amplifying prokaryotic symbiont rRNA sequences from individual marine planktonic eukaryotic host cells belonging to the tintinnid genus Codonella, the spongiose radiolarian genus Dictyocoryne, and several Dinophysoid genera (Amphisolenia, Citharistes, Dinophysis, Histioneis, Ornithocercus). Of the 93 sequences obtained from 67 clone libraries, 26% were most similar to a variety of heterotrophic bacteria and 4% were most similar to plastids. Most (70%) of the sequences had the greatest similarity to cyanobacterial 16S rRNA sequences. Several (10%) of these had low sequence identity (<94%) to cyanobacteria in the database, suggesting that they represent novel cyanobacterial lineages. Fifty‐three percent of the cyanobacterial sequences were most closely related (>96% identical) to Synechococcus sp., and three were >99% identical to Prochlorococcus sp. Subgroups of sequences most similar to Synechococcus sp. were derived from multiple host types, indicating that the same symbiont was capable of forming an association with a variety of host organisms. Sixteen libraries yielded two or three divergent (from 2% to 25% different) sequence types, indicating the presence of mixed assemblages in single host cells. This study provides the first insight into the phylogenetic diversity of the symbiotic cyanobacteria of open ocean protists.
Information Uncertainty and Stock Returns
Authors: ZHANG X. FRANK
Published: January 2006

There is substantial evidence of short‐term stock price continuation, which the prior literature often attributes to investor behavioral biases such as underreaction to new information. This paper investigates the role of information uncertainty in price continuation anomalies and cross‐sectional variations in stock returns. If short‐term price continuation is due to investor behavioral biases, we should observe greater price drift when there is greater information uncertainty. As a result, greater information uncertainty should produce relatively higher expected returns following good news and relatively lower expected returns following bad news. My evidence supports this hypothesis.
Asset Pricing Implications of Nonconvex Adjustment Costs and Irreversibility of Investment
Authors: COOPER ILAN
Published: January 2006

This paper derives a real options model that accounts for the value premium. If real investment is largely irreversible, the book value of assets of a distressed firm is high relative to its market value because it has idle physical capital. The firm's excess installed capital capacity enables it to fully benefit from positive aggregate shocks without undertaking costly investment. Thus, returns to equity holders of a high book‐to‐market firm are sensitive to aggregate conditions and its systematic risk is high. Simulations indicate that the model goes a long way toward accounting for the observed value premium.
The Price Impact and Survival of Irrational Traders
Authors: KOGAN LEONID , ROSS STEPHEN A. , WANG JIANG , WESTERFIELD MARK M.
Published: January 2006

Milton Friedman argued that irrational traders will consistently lose money, will not survive, and, therefore, cannot influence long‐run asset prices. Since his work, survival and price impact have been assumed to be the same. In this paper, we demonstrate that survival and price impact are two independent concepts. The price impact of irrational traders does not rely on their long‐run survival, and they can have a significant impact on asset prices even when their wealth becomes negligible. We also show that irrational traders' portfolio policies can deviate from their limits long after the price process approaches its long‐run limit.
Wealth and Executive Compensation
Authors: BECKER BO
Published: January 2006

Using new data on the wealth of Swedish CEOs, I show that higher wealth CEOs receive stronger incentives. Since high wealth (excluding own‐firm holdings) implies low absolute risk aversion, this is consistent with a risk aversion explanation. To examine whether wealth is likely to proxy for power, I use lagged wealth (typically measured before the CEO was hired), and the results remain for one of two incentive measures. Also, the wealth–incentive result is not stronger for CEOs likely to face limited owner oversight. Finally, wealth is unrelated to pay levels, and is hence unlikely to proxy for skill.
Initial Public Offerings: An Analysis of Theory and Practice
Authors: BRAU JAMES C. , FAWCETT STANLEY E.
Published: January 2006

We survey 336 chief financial officers (CFOs) to compare practice to theory in the areas of initial public offering (IPO) motivation, timing, underwriter selection, underpricing, signaling, and the decision to remain private. We find the primary motivation for going public is to facilitate acquisitions. CFOs base IPO timing on overall market conditions, are well informed regarding expected underpricing, and feel underpricing compensates investors for taking risk. The most important positive signal is past historical earnings, followed by underwriter certification. CFOs have divergent opinions about the IPO process depending on firm‐specific characteristics. Finally, we find the main reason for remaining private is to preserve decision‐making control and ownership.
Finance as a Barrier to Entry: Bank Competition and Industry Structure in Local U.S. Markets
Authors: CETORELLI NICOLA , STRAHAN PHILIP E.
Published: January 2006

This paper tests how competition in local U.S. banking markets affects the market structure of nonfinancial sectors. Theory offers competing hypotheses about how competition ought to influence firm entry and access to bank credit by mature firms. The empirical evidence, however, strongly supports the idea that in markets with concentrated banking, potential entrants face greater difficulty gaining access to credit than in markets in which banking is more competitive.
Investor Tax Heterogeneity and Ex‐Dividend Day Trading Volume
Authors: DHALIWAL DAN , LI OLIVER ZHEN
Published: January 2006

We propose that ex‐dividend day excess volume is motivated by tax heterogeneity among investors, and thus is increasing in investor tax heterogeneity. Institutional ownership is our measure of heterogeneity. Since investor heterogeneity is a concave function of institutional ownership, we hypothesize that ex‐day volume is a concave function of institutional ownership. Cross‐sectional tests support the tax‐motivated trading hypothesis. Additional tests, using trade size and pension ownership as proxies for institutional trades, yield similar results. We contribute to the literature by considering the interaction between payout policy and ownership structure in explaining the cross‐sectional variation in ex‐day volume.
Histopathological changes in oral mucosa due to takhzeen al‐qat: a study of 70 biopsies
Authors: Ali Aiman A. , Al‐Sharabi Ali K. , Aguirre José M.
Published: January 2006

Background:  Chewing qat leaves (takhzeen al‐qat) is a common habit in East Africa and Yemen. It has been reported to cause different systemic effects. At the oral mucosa, it causes clinical changes that appear as white lesions. The aim of this paper was to study the histopathological changes in the oral mucosa related to takhzeen al‐qat.

Method:  Seventy biopsies were studied. Biopsies were divided into three groups: (G1) Forty biopsies were taken from the oral mucosa of the chewing side. (G2) Twenty biopsies were taken from the oral mucosa of the opposite side and (G3) 10 biopsies were taken from the oral mucosa of non‐chewing volunteers. All biopsies were conventionally prepared, paraffin embedded and histopathological protocol was followed for each case to study the histopathological changes.

Results:  Acanthosis appeared in 97.5% (G1) and 50% (G2), parakeratosis in 45% (G1) and 0% (G2), orthokeratosis in 25% (G1) and 10% (G2), abnormal rete ridges in 97.5% (G1) and 25% (G2), intracellular edema in 80% (G1) and 65% (G2), inflammatory infiltration in the subjacent connective tissue of 55% (G1) and 5% (G2), increased amount of collagenous fibers in 47.5% (G1) and 0% (G2), and mild epithelial dysplasia in 25% (G1) and 0% (G2). Biopsies taken from G3 showed no histopathological changes except one case with intracellular edema. Differences were statistically significant.

Conclusion:  Takhzeen al‐qat caused histopathological changes in the oral mucosa at the side of chewing; however, these changes were innocuous and without any evidence of malignancy.
Oral tuberculosis associated with a treatment with anti‐rheumatic drugs
Authors: Kolokotronis Alexandros , Avramidou Evanda , Zaraboukas Thomas , Mandraveli Kalliopi , Alexiou Stella , Antoniades Demetrios
Published: January 2006

Background:  The use of immunosuppressive medication is a dominant risk factor for infection in patients with rheumatoid arthritis (RA). Methotrexate (MTX) is one of the traditional disease‐modifying antirheumatic drugs. Adalimumab [a human anti‐tumor necrosis factor‐α (anti‐TNF‐α) monoclonal antibody] represent an important advance in the treatment of RA and has been recently come in use. TNF‐α plays a role in the host defense against Mycobacterium tuberculosis and notably in granuloma formation. Infections occur at a high rate among those who use one or the combination of the two medications.

Method:  We examined a female patient that was referred to our department for evaluation and treatment of a granular lesion on the soft palate and uvula, complaining of mild dysphagia. The patient was treated for 4 months with MTX and adalimumab for RA before the oral lesion appeared.

Results:  The histopathological examination of a specimen of the oral lesion, taken by biopsy, showed a chronic inflammation characterized by tuberculous granulomas. Polymerase chain reaction test and culture of a new specimen was positive for M. tuberculosis.

Conclusions:  The therapeutic use of MTX or/and adalimumab for the treatment of RA or few others diseases, can cause oral tuberculosis.
Relationship between TNF‐α and TUNEL‐positive chondrocytes in antigen‐induced arthritis of the rabbit temporomandibular joint
Authors: Hirota Yuriko , Habu Manabu , Tominaga Kazuhiro , Sukedai Miho , Matsukawa Akihiro , Nishihara Tatsuji , Fukuda Jinichi
Published: January 2006

Background:  Terminal deoxynucleotidyl transferase‐mediated deoxyuridine triphosphate biotin nick end‐labeling (TUNEL) staining is a widely accepted method for the detection of DNA fragmentation in nuclei of apoptotic cells. Tumor necrosis factor (TNF)‐α is closely associated with changes in condylar cartilage and modulates apoptosis in various tissues including cartilage. The aim of this study was to investigate the relationship between apoptotic chondrocytes and TNF‐α in a rabbit model of arthritis.

Method:  Unilateral temporomandibular joint (TMJ) arthritis was induced in 20 adult New Zealand White rabbits. From 1 day to 6 weeks after the induction of arthritis, immunohistochemical analysis for TNF‐α and TUNEL was performed.

Results:  In condylar cartilage, TNF‐α‐positive cells and TUNEL‐positive cells were localized together. TNF‐α‐positive chondrocytes seemed to precede TUNEL‐positive cells.

Conclusions:  The results of the present study suggest that TNF‐α may be involved in apoptosis and/or apoptotic necrosis of chondrocytes as TMJ arthritis progresses from the acute to chronic stage.
Ectomesenchymal chondromyxoid tumor of the hard palate – a case report
Authors: Nigam Sonu , Dhingra Kajal Kiran , Gulati Achal
Published: January 2006

Ectomesenchymal chondromyxoid tumor (ECMT) is a rare tumor. Only 26 cases of ECMT have been reported, all occurred in the anterior tongue. We present a case of a 30‐year‐old male with a nodule in the hard palate, which was reported as ECMT on histopathology. The differential diagnosis considered included are extraskeletal myxoid chondroma, ECMT, pleomorphic adenoma, oral focal mucinosis, chondroid choristoma, and ossifying fibromyxoid tumor. After serial sections no other component was observed and a diagnosis of ECMT was made by exclusion. The patient is asymptomatic on follow up. A review of existing literature is also presented here.
Isolation and characterization of synovial cells from the human temporomandibular joint
Authors: Nagai H. , Miyamoto Y. , Nakata A. , Hatakeyama S. , Iwanami Y. , Fukuda M.
Published: January 2006

Background:  The synovial tissues with temporomandibular disorders (TMDs) often show chronic inflammatory changes and the synovial cells participate in the pathogenic processes of TMDs. The synovial membrane is composed of a synovial lining layer and a connective sublining layer. The synovial lining layer is made up of two kinds of cells: macrophage‐like type A and fibroblastic type B cells. The aim of this study was to isolate and characterize synovial cells from the human temporomandibular joint (TMJ).

Methods:  Synovial cells were isolated using an explant culture method. Then, we characterized the cultured synovial cells (SGA2 cells) using immunocytochemistry.

Results:  SGA2 cells expressed the fibroblastic markers vimentin and prolyl 4‐hydroxylase; they also expressed laminin and heat shock protein 27, all of which are markers of type B cells. However, some cells expressed the macrophage marker CD68. These CD68‐positive cells simultaneously expressed laminin.

Conclusions:  We isolated and cultured synovial type B cells from the human TMJ, and identified the presence of intermediate type synovial lining cells, having the phenotypic properties of both type A and type B cells, among the synovial lining cells.
The efficacy of amelxanox OraDiscTM on the prevention of recurrent minor aphthous ulceration
Authors: Murray B. , Biagioni P. A. , Lamey P.‐J.
Published: January 2006

Background:  The study was designed to determine the efficacy of OraDiscTM (active component 2 mg amlexanox) on the prevention of aphthous ulcers treated at the prodromal stage.

Methods:  Thermographic imaging was used to confirm the presence of a prodromal ulcer. Fifty‐two patients were randomized to receive OraDiscTM (N = 26) or vehicle patches (N = 26). Patches were applied four times a day for 72 h over the prodromal area. The percentage of subjects who developed an ulcer at 72 h was compared between groups using the Fisher's exact test.

Results:  About 50% of subjects in the OraDiscTM group developed an ulcer by day 4 compared with 69% in the vehicle group. Erythema score, ulcer size, pain scores and thermographically active area and temperature all showed trends towards healing in the OraDiscTM group.

Conclusion:  The OraDiscTM prevents ulcers from developing when compared with the vehicle patch.
Effects of Patch Size and Floral Herbivory on Seed Set in Trichogoniopsis adenantha (Asteraceae) in Southeastern Brazil1
Authors: Salomão Adriana T. , Martins Luiz F. , Ribeiro Ricardo da S. , Romero Gustavo Q.
Published: January 2006

The effects of patch size and floral herbivory on reproductive success of Trichogoniopsis adenantha (Asteraceae) were studied in a semideciduous forest in southeastern Brazil. Plants in large patches and capitula not attacked by endophagous insects had higher seed set. The consequences of living in large or small patches for plant reproductive success are discussed.
Purkinje cells in the lateral cerebellum of the cat encode visual events and target motion during visually guided reaching
Authors: Miles Ömür Budanur , Cerminara Nadia L. , Marple‐Horvat Dilwyn E.
Published: January 2006

In this study the receipt of visual information by the lateral cerebellum and its contribution to a motor output was studied using single unit recording of cerebellar cortical neurones in cats trained to perform visually guided reaching. The activity of Purkinje cells and other cortical neurones in the lateral cerebellum was investigated in relation to various aspects of the task, such as visual events, parameters of target movement, and limb and eye movements. Two‐thirds (66%) of Purkinje cells tested could signal simple visual events, such as a flash of light. Neurones were also capable of detecting other less potent, but behaviourally important visual events, such as a ‘GO’ signal (LED brightening). Half of the cells tested were responsive to the on‐going motion of the visual target, displaying tonically altered discharge rates for as long as it was moving, and a ‘preferred’ target velocity. A small proportion of cells showed short latency visual modulation that persisted during the forelimb reach. Anatomical tracing studies confirmed that the recordings were obtained from the D1 zone of crus I. In summary, cells in this region of lateral cerebellar cortex perform simple visual functions, such as event detection, but also more complex visual functions, such as encoding parameters of target motion, and their visual responsiveness is appropriate for a role in accurate visually guided reaching to a moving target.
Evaluation of plateau‐potential‐mediated ‘warm up’ in human motor units
Authors: Fuglevand Andrew J. , Dutoit Andrea P. , Johns Richard K. , Keen Douglas A.
Published: January 2006

Spinal motor neurones can exhibit sustained depolarization in the absence of maintained synaptic or injected current. This phenomenon, referred to as a plateau potential, is due to the activation of monoamine‐dependent persistent inward currents. Accordingly, activation of a plateau potential should result in a decrease in the excitatory synaptic drive required to activate a motor unit. This, in turn, has been suggested to cause a progressive decline in the muscle force at which motor units are recruited during repeated voluntary contractions. Such a progressive decrease in threshold force associated with preceding activation of a plateau potential is referred to as ‘warm up’. Furthermore, activation of a plateau potential is thought to manifest itself as a decrease in the derecruitment force compared to recruitment force. Multiple muscles, however, can contribute to the detected force and their relative contributions may vary over time, which could confound measures of recruitment and derecruitment force. Therefore, the purpose of this study was to compare the recruitment and derecruitment forces of single motor units in the human extensor digitorum and tibialis anterior during repetitive triangular‐force contractions in which the contributions of other muscles had been minimized. In both muscles, we found that the recruitment thresholds of single motor units were unchanged during repeated contractions, and that the derecruitment force was consistently greater than the recruitment force. These results suggest either that plateau potentials were not engaged (or were rapidly extinguished) under these experimental conditions or that changes in recruitment and derecruitment force are not suitable criteria for detecting them.
Cycling efficiency in humans is related to low UCP3 content and to type I fibres but not to mitochondrial efficiency
Authors: Mogensen M. , Bagger M. , Pedersen P. K. , Fernström M. , Sahlin K.
Published: January 2006

The purpose of this study was to investigate the hypothesis that cycling efficiency in vivo is related to mitochondrial efficiency measured in vitro and to investigate the effect of training status on these parameters. Nine endurance trained and nine untrained male subjects (, respectively) completed an incremental submaximal efficiency test for determination of cycling efficiency (gross efficiency, work efficiency (WE) and delta efficiency). Muscle biopsies were taken from m. vastus lateralis and analysed for mitochondrial respiration, mitochondrial efficiency (MEff; i.e. P/O ratio), UCP3 protein content and fibre type composition (% MHC I). MEff was determined in isolated mitochondria during maximal (state 3) and submaximal (constant rate of ADP infusion) rates of respiration with pyruvate. The rates of mitochondrial respiration and oxidative phosphorylation per muscle mass were about 40% higher in trained subjects but were not different when expressed per unit citrate synthase (CS) activity (a marker of mitochondrial density). Training status had no influence on WE (trained 28.0 ± 0.5, untrained 27.7 ± 0.8%, N.S.). Muscle UCP3 was 52% higher in untrained subjects, when expressed per muscle mass (P < 0.05 versus trained). WE was inversely correlated to UCP3 (r=−0.57, P < 0.05) and positively correlated to percentage MHC I (r= 0.58, P < 0.05). MEff was lower (P < 0.05) at submaximal respiration rates (2.39 ± 0.01 at 50%) than at state 3 (2.48 ± 0.01) but was neither influenced by training status nor correlated to cycling efficiency. In conclusion cycling efficiency was not influenced by training status and not correlated to MEff, but was related to type I fibres and inversely related to UCP3. The inverse correlation between WE and UCP3 indicates that extrinsic factors may influence UCP3 activity and thus MEff in vivo.
The anti‐angiogenic VEGF isoform VEGF165b transiently increases hydraulic conductivity, probably through VEGF receptor 1 in vivo
Authors: Glass C. A. , Harper S. J. , Bates D. O.
Published: January 2006

Vascular endothelial growth factor (VEGF) is the principal agent that increases microvascular permeability during physiological and pathological angiogenesis. VEGF is differentially spliced to form two families of isoforms: VEGFxxx, and VEGFxxxb. Whereas VEGF165 stimulates angiogenesis, VEGF165b is anti‐angiogenic. To determine the effect of VEGF165b on permeability, hydraulic conductivity (Lp) was measured in individually perfused microvessels in the mesentery of frogs and rats. As with VEGF165, VEGF165b increased Lp in amphibian (2.4 ± 0.3‐fold) and mammalian (1.9 ± 0.2‐fold) mesenteric microvessels. A dose–response relationship showed that VEGF165b (EC50, 0.65 pm) was approximately 25 times more potent than VEGF165 (EC50, 16 pm) in amphibian microvessels. VEGF165 has been shown to increase permeability through VEGF receptor 2 (VEGF‐R2) signalling. However, VEGF165b increased Lp of frog vessels to the same extent in the presence of the VEGF‐R2 inhibitor ZM323881, indicating that it does not increase permeability via VEGF‐R2 signalling, and was inhibited by the VEGF receptor inhibitor SU5416 at doses that are specific for VEGF receptor 1 (VEGF‐R1). VEGF165b, in contrast to VEGF165, did not result in a sustained chronic increase in Lp. These results show that although VEGF165b is anti‐angiogenic in the mesentery, it does signal in endothelial cells in vivo resulting in a transient, but not sustained, increase in microvascular Lp, probably through VEGF‐R1.
Pore properties and pharmacological features of the P2X receptor channel in airway ciliated cells
Authors: Ma Weiyuan , Korngreen Alon , Weil Simy , Cohen Enbal Ben‐Tal , Priel Avi , Kuzin Liubov , Silberberg Shai D.
Published: January 2006

Airway ciliated cells express an ATP‐gated P2X receptor channel of unknown subunit composition (P2Xcilia) which is modulated by Na+and by long exposures to ATP. P2Xciliawas investigated by recording currents from freshly dissociated rabbit airway ciliated cells with the patch‐clamp technique in the whole‐cell configuration. During the initial continuous exposure to extracellular ATP, P2Xciliacurrents gradually increase in magnitude (priming), yet the permeability toN‐methyl‐d‐glucamine (NMDG) does not change, indicating that priming does not arise from a progressive change in pore diameter. Na+, which readily permeates P2Xciliareceptor channels, was found to inhibit the channel extracellular to the electric field. The rank order of permeability to various monovalent cations is: Li+, Na+, K+, Rb+, Cs+, NMDG+and TEA+, with a relative permeability of 1.35, 1.0, 0.99, 0.91, 0.79, 0.19 and 0.10, respectively. The rank order for the alkali cations follows an Eisenman series XI for a high‐strength field site. Ca2+has been estimated to be 7‐fold more permeant than Na+. The rise in [Ca2+]iin ciliated cells, induced by the activation of P2Xcilia, is largely inhibited by either Brilliant Blue G or KN‐62, indicating that P2X7may be a part of P2Xcilia. P2Xciliais augmented by Zn2+and by ivermectin, and P2X4receptor protein is detected by immunolabelling at the basal half of the cilia, strongly suggesting that P2X4is a component of P2Xciliareceptor channels. Taken together, these results suggest that P2Xciliais either assembled from P2X4and P2X7subunits, or formed from modified P2X4subunits.
Cyclothiazide induces robust epileptiform activity in rat hippocampal neurons both in vitro and in vivo
Authors: Qi Jinshun , Wang Yun , Jiang Min , Warren Philippa , Chen Gong
Published: January 2006

Cyclothiazide (CTZ) is a potent blocker of AMPA receptor desensitization. We have recently demonstrated that CTZ also inhibits GABAA receptors. Here we report that CTZ induces robust epileptiform activity in hippocampal neurons both in vitro and in vivo. We first found that chronic treatment of hippocampal cultures with CTZ (5 μm, 48 h) results in epileptiform activity in the majority of neurons (80%). The epileptiform activity lasts more than 48 h after washing off CTZ, suggesting a permanent change of the neural network properties after CTZ treatment. We then demonstrated in in vivo recordings that injection of CTZ (5 μmol in 5 μl) into the lateral ventricles of anaesthetized rats also induces spontaneous epileptiform activity in the hippocampal CA1 region. The epileptogenic effect of CTZ is probably due to its enhancing glutamatergic neurotransmission as shown by increasing the frequency and decay time of mEPSCs, and simultaneously inhibiting GABAergic neurotransmission by reducing the frequency of mIPSCs. Comparing to a well‐known epileptogenic agent kainic acid (KA), CTZ affects neuronal activity mainly through modulating synaptic transmission without significant change of the intrinsic membrane excitability. Unlike KA, which induces significant cell death in hippocampal cultures, CTZ treatment does not result in any apparent neuronal death. Therefore, the CTZ‐induced epilepsy model may provide a novel research tool to elucidate the molecular and cellular mechanisms of epileptogenesis without any complication from drug‐induced cell death. The long‐lasting epileptiform activity after CTZ washout may also make it a very useful model in screening antiepileptic drugs.
A possible role of the junctional face protein JP‐45 in modulating Ca2+ release in skeletal muscle
Authors: Gouadon E. , Schuhmeier R. P. , Ursu D. , Anderson A. A. , Treves S. , Zorzato F. , Lehmann‐Horn F. , Melzer W.
Published: January 2006

We investigated the functional role of JP‐45, a recently discovered protein of the junctional face membrane (JFM) of skeletal muscle. For this purpose, we expressed JP‐45 C‐terminally tagged with the fluorescent protein DsRed2 by nuclear microinjection in myotubes derived from the C2C12 skeletal muscle cell line and performed whole‐cell voltage‐clamp experiments. We recorded in parallel cell membrane currents and Ca2+ signals using fura‐2 during step depolarization. It was found that properties of the voltage‐activated Ca2+ current were not significantly changed in JP‐45–DsRed2‐expressing C2C12 myotubes whereas the amplitude of depolarization‐induced Ca2+ transient was decreased compared to control myotubes expressing only DsRed2. Converting Ca2+ transients to Ca2+ input flux using a model fit approach to quantify Ca2+ removal, the change could be attributed to an alteration in voltage‐activated Ca2+ permeability rather than to altered removal properties or a lower Ca2+ content of the sarcoplasmic reticulum (SR). Determining non‐linear capacitive currents revealed a reduction of Ca2+ permeability per voltage‐sensor charge. The results may be explained by a modulatory effect of JP‐45 related to its reported in vitro interaction with the dihydropyridine receptor and the SR Ca2+ binding protein calsequestrin (CSQ).
A Two-Step Thermochemical Water Splitting by Iron-Oxide on Stabilized Zirconia
Authors: Kodama Tatsuya , Nakamuro Yumiko , Mizuno Takayuki
Published: January 2006

The thermochemical two-step water splitting cycle was examined by using an iron oxide supported on yttrium-stabilized, cubic zirconia (YSZ) as the working material with a view toward direct conversion of solar high-temperature heat to clean hydrogen energy. In the first step of the cycle, the YSZ-supported Fe3O4 was thermally decomposed to the reduced phase at 1400°C under an inert atmosphere. The reduced solid phase was oxidized back to the original phase (the YSZ-supported Fe3O4) with steam to generate hydrogen below 1000°C. A new redox pair, which is different from the Fe3O4-FeO pair previously examined by others, served as the working solid material on this YSZ-supported Fe3O4. Our new redox reaction proceeded as follows. The Fe3O4 reacted with YSZ to produce an Fe2+-containing ZrO2 phase by releasing oxygen molecules in the first step: The Fe2+ ions entered into the cubic YSZ lattice. In the second step, the Fe2+-containing YSZ generated hydrogen via steam splitting to reproduce Fe3O4 on the cubic YSZ support. This cyclic reaction could be repeated with a good repeatability of the reaction below 1400°C.
Modeling of a Solar Reactor for Single-Wall Nanotube Synthesis
Authors: Flamant G. , Bijeire M. , Luxembourg D.
Published: January 2006

Experimental results with a 50kW solar reactor producing 10-15g∕h single-wall carbon nanotube’s rich soot have shown that good quality product was obtained with helium and rather bad product with argon. This result is explained using a computational fluid dynamics model of the reactor accounting for fluid flow, heat transfer, and mass transfer. The bad results in argon were linked to the quenching of carbon vapor in the vaporization zone that resulted in the growth of carbon nanoparticles in spite of carbon-metal clusters (single-wall carbon nanotube precursor). By contrast, the vaporized materials (C, Ni, and Co species) at the target surface were well mixed in helium, and single-wall carbon nanotubes (SWNTs) might grow in the annealing and cooling zone at the backside of the reactor. The same numerical approach may be used to design modifications of the reactor in order to favor the growth of SWNTs.
Modeling Phase Change Materials With Conduction Transfer Functions for Passive Solar Applications
Authors: Barbour Jason P. , Hittle Douglas C.
Published: January 2006

The use of passive solar design in our homes and buildings is one way to offset the ever-increasing dependence on fossil fuels and the resulting pollution to our air, our land, and our waters. A well-designed sunroom has the potential to reduce the annual heating loads by one-third or more. By integrating phase change materials (PCMs) into building elements, such as floor tile and wallboard, the benefits of the sunroom can be further enhanced by providing enhanced energy storage. To maximize benefits from PCMs, an engineering analysis tool is needed to provide insight into the most efficient use of this developing technology. Thus far, modeling of the PCMs has been restricted to finite difference and finite element methods, which are not well suited to inclusion in a comprehensive annual building simulation program such as BLAST or EnergyPlus. Conduction transfer functions (CTFs) have long been used to predict transient heat conduction in such programs. Phase changes often do not occur at a single temperature, but do so over a range of temperatures. The phase change energy can be represented by an elevated heat capacity over the temperature range during which the phase change occurs. By calculating an extra set(s) of CTFs for the phase change properties, the CTF method can be extended to include the energy of phase transitions by switching between the two (or more) sets of CTFs. This method can be used to accurately predict the internal and external temperatures of PCM-containing building elements during transient heat conduction. The amount of energy storage and release during a phase transition can also be modeled with this method, although there may be some degree of inaccuracy due to switching between two or more sets of CTFs. CTFs have the potential to provide an efficient method of modeling PCMs in annual building simulation programs, but more work is needed to reduce errors associated with their use.
Solar Carbothermic Reduction of ZnO in a Two-Cavity Reactor: Laboratory Experiments for a Reactor Scale-Up
Authors: Kräupl S. , Frommherz U. , Wieckert C.
Published: January 2006

Solar energy can be stored chemically by using concentrated solar irradiation as an energy source for carbothermic ZnO reduction. The produced Zn might be used for the production of electricity in Zn-air fuel cells or of H2 by splitting water. In either case the product is again ZnO which can be reprocessed in the solar process step. This innovative concept will be scaled up to 300kW solar input power within the so-called SOLZINC-project. In this paper we report on experimental results obtained with a two cavity reactor operated at solar power inputs of 3-8kW in a solar furnace. The objective was to generate input data which are necessary for designing the scaled up reactor, such as the effect of process temperature (1100-1300°C) and carrier gas (N2 and CO) on the overall reaction rate. Furthermore, construction materials were tested and a variety of carbonaceous materials were screened for their use as reducing agents by means of thermogravimetric measurements. As a result, beech charcoal was chosen as the standard reducing agent.
Photovoltaic Maximum Power Point Varying with Illumination and Temperature
Authors: Radziemska E. , Klugmann E.
Published: January 2006

This paper presents the experimental results and discusses the track of the maximum power point on the current-voltage curve of a PV module due to changes of the illumination level and temperature. A time decrease of the voltage and simultaneous temperature increase during the initial stage of irradiation has been observed. Some practical implementation aspects of a maximum power point tracking unit, which match the current and voltage characteristics of the load to the PV module’s maximum power point automatically, are also discussed. A linear decrease of the maximum output power Pm with temperature increase has been observed and the temperature coefficient was derivate. Temperature coefficients for Voc, Isc, Vmpp, Impp, and ηPV have been determined for the photovoltaic module. Also the radiation-rate coefficient at constant temperature has been calculated.
Latent Heat Storage in a Two-Phase Thermosyphon Solar Water Heater
Authors: Lee Wen-Shing , Chen Bo-Ren , Chen Sih-Li
Published: January 2006

This article experimentally studies the thermal performance of latent heat storage in a two-phase thermosyphon solar water heater, which utilizes the superior heat transfer characteristics of boiling and condensation, and eliminates drawbacks found in the conventional solar water heater. Experimental investigations are first conducted to study the thermal behavior of tricosane (paraffin wax 116), water, and sodium acetate (NaCH3COO∙3H2O) used as energy storage materials. The results indicate that tricosane provides many advantages to be the energy storage material in the latent heat storage system. This study also examines the functions of charge and discharge thermal behaviors in a two-phase thermosyphon solar water heater. The results show that the system gives optimum charge and discharge performance under 40% alcohol fill ratio and with tricosane used as the energy storage material, and displays an optimum charge efficiency of 73% and optimum discharge efficiency of 81%.
Annular Compound Parabolic Concentrator
Authors: Lipiński W. , Steinfeld A.
Published: January 2006

The annular compound parabolic concentrator (CPC) is a body of revolution consisting of two axisymmetric surfaces produced by rotating a classical two-dimensional CPC around an axis parallel to the CPCs axis. Its ability to further concentrate incoming radiation when used in tandem with a primary solar parabolic concentrator is analyzed by the Monte Carlo ray-tracing technique. Potential applications are found in capturing the annular portion of primary concentrated solar radiation and augmenting its power flux intensity.
Multi-tower Line Focus Fresnel Array Project
Authors: Mills David R. , Morrison Graham , Pye John , Le Lièvre Peter
Published: January 2006

As an alternative to conventional tracking solar thermal trough systems, one may use line focus Fresnel reflector systems. In a conventional Fresnel reflector design, each field of reflectors is directed to a single tower. However, efficient systems of very high ground utilisation can be setup if a field of reflectors uses multiple receivers on different towers. This paper describes a line focus system, called the compact linear fresnel reflector system and a project to produce an initial 95 MWth solar array. The array will be used as a retrofit preheater for a coal fired generating plant.
Improved Accuracy Models For Hourly Diffuse Solar Radiation
Authors: Muneer T. , Munawwar S.
Published: January 2006

Solar energy applications require readily available, site-oriented, and long-term solar data. However, the frequent unavailability of diffuse irradiation, in contrast to its need, has led to the evolution of various regression models to predict it from the more commonly available data. Estimating the diffuse component from global radiation is one such technique. The present work focuses on improvement in the accuracy of the models for predicting horizontal diffuse irradiation using hourly solar radiation database from nine sites across the globe. The influence of sunshine fraction, cloud cover, and air mass on estimation of diffuse radiation is investigated. Inclusion of these along with hourly clearness index, leads to the development of a series of models for each site. Estimated values of hourly diffuse radiation are compared with measured values in terms of error statistics and indicators like, R2, mean bias deviation, root mean square deviation, skewness, and kurtosis. A new method called “the accuracy score system” is devised to assess the effect on accuracy with subsequent addition of each parameter and increase in complexity of equation. After an extensive evaluation procedure, extricate but adequate models are recommended as optimum for each of the nine sites. These models were found to be site dependent but the model types were fairly consistent for neighboring stations or locations with similar climates. Also, this study reveals a significant improvement from the conventional k-kt regression models to the presently proposed models.
Exergetic, Thermal, and Externalities Analyses of a Cogeneration Plant
Authors: Bailey Margaret B. , Curtiss Peter , Blanton CPT Paul H. , McBrayer CPT Thomas B.
Published: January 2006

A thermodynamic study of an 88.4MW cogeneration plant located in the United States is presented in this paper. The feedstock for this actual plant is culm, the waste left from anthracite coal mining. Before combustion in circulating fluidized bed boilers, the usable carbon within the culm is separated from the indigenous rock. The rock and ash waste from the combustion process fill adjacent land previously scared by strip mining. Trees and grass are planted in these areas as part of a land reclamation program. Analyses based on the first and second laws of thermodynamics using actual operating data are first presented to acquaint the reader with the plant’s components and operation. Using emission and other relevant environmental data from the plant, an externalities study is outlined that estimates the plant’s effect on the local population. The results show that the plant’s cycle performs with a coefficient of utilization of 29% and an approximate exergetic efficiency of 34.5%. In order to increase these values, recommended improvements to the plant are noted. In addition, the externality costs associated with the estimated SO2 and NOX discharge from the culm fed plant are approximately 1mil∕kWh produced. This is considerably lower (85–95%) than those associated with a similarly sized coal fed plant. The plant’s cycle efficiencies are lower than those associated with more modern technologies; such as an integrated gas turbine combined cycle. However, given the abundant, inexpensive supply of feedstock located adjacent to the plant and the environmental benefit of removing culm banks, the plant’s existing operation is unique from an economical and environmental viewpoint.
Transient and Rate-Dependent Performance of Conventional Electric Storage Water Heating Systems
Authors: McMenamy J. W. , Homan K. O.
Published: January 2006

Electric resistance water heaters are relatively simple and are therefore one of the most common water heating configurations. Due to constraints on the allowable instantaneous electrical power draw, most electric water heating systems incorporate a sizable thermal storage component. The inherently unsteady storage component therefore has an overwhelming impact on the system behavior. In this investigation, a residential-scale electric storage water heater was tested across a range of flow rates for both powered and nonpowered discharge processes as well as for charge processes with no throughflow. The flow dynamics internal to the storage volume is shown to be strongly multidimensional and transient, especially when the internal heating elements are energized. Comparison of the measured data to the performance limits of a system with a fully mixed or a perfectly stratified storage element reveals that the conventional system operates relatively near to the fully mixed limit. As a result, there appears to be significant potential for improvements in system performance through reductions in the level of thermal mixing internal to the storage volume.