bluuebunny/crossref_metadata_2025 huggingface dataset:
Combined use of two transcriptional reporters improves signalling assays for G protein‐coupled receptors in fission yeast
Authors: Das Anamika , Forfar Rachel , Ladds Graham , Davey John
Published: September 2006

The biochemical and genetic tractability of yeasts make them ideal hosts for the analysis of signalling from G protein‐coupled receptors (GPCRs). Selected modifications to the strains allow the introduction of non‐yeast components, while signal‐dependent expression of reporter genes provides growth selection or enzyme read‐out as assays for signalling. One issue with such systems is reporter expression in the absence of stimulation, usually because of spontaneous activation of intracellular signalling components and/or incomplete repression of the signal‐dependent promoter. This limits the difference between reporter activity in the presence and absence of stimulation, often referred to as the signal : background ratio. In an effort to extend the applicability of the yeast system, we generated a Schizosaccharomyces pombe strain containing pheromone‐dependent reporters for both growth selection and β‐galactosidase production. Simultaneous use of the two reporters provided several advantages over strains expressing only one reporter, particularly when coupled to the use of a competitive inhibitor of the nutritional reporter. For example, the β‐galactosidase signal : background ratio following stimulation with 10−6 M P‐factor increased from 35 for a strain containing a single lacZ reporter to almost 2500 for the double reporter. The sensitivity of the system was also improved, with higher signal : background ratios allowing detection of lower concentrations of P‐factor. Although we have used Sz. pombe and focused on GPCR‐based induction of β‐galactosidase, the principles described can be applied to other yeasts, different signalling pathways and alternative reporters. Copyright © 2006 John Wiley & Sons, Ltd.
Cell surface characterization of Yarrowia lipolytica IMUFRJ 50682
Authors: Amaral P. F. F. , Lehocky M. , Barros‐Timmons A. M. V. , Rocha‐Leão M. H. M. , Coelho M. A. Z. , Coutinho J. A. P.
Published: September 2006

In the present work, the surface characteristics of a wild‐type strain of Yarrowia lipolytica (IMUFRJ50682) were investigated. Six different methods to characterize cell surfaces—adhesion to polystyrene; hydrophobic interaction chromatography (HIC); microbial adhesion to solvents (MATS) test; zeta potential; microbial adhesion to hydrocarbons (MATH) test; and contact angle measurement (CAM)—were employed to explain the cell surface behaviour of Y. lipolytica (IMUFRJ50682). This Y. lipolytica strain presents significant differences at the cell surface compared with another Y. lipolytica strain (W29) previously reported in the literature. The main difference is related to the higher cell adhesion to non‐polar solvents. The proteins present on the cell wall of Y. lipolytica IMUFRJ50682 seem to play an important role in these particular surface characteristics because of the consistent reduction of this yeast hydrophobic character after the action of pronase on its cell wall. Copyright © 2006 John Wiley & Sons, Ltd.
Involvement of protein kinases in self‐organization of the rhythm of protein synthesis by direct cell—cell communication
Authors: Brodsky Vsevolod Y. , Zvezdina Natalia D. , Fateeva Valentina I. , Malchenko Ludmila A.
Published: September 2006

Primary cultures of rat hepatocytes grown on slides were studied in serum‐free medium. Ultradian protein synthesis rhythm was used as a marker of synchronization of individual oscillations, resulting in the formation of a common rhythm of the cell population, i.e. cell—cell self‐organization. Dense synchronous and sparse non‐synchronous cultures were used to estimate effect of protein kinase activity on the kinetics of protein synthesis. Treatment of dense cultures with the inhibitors H7 (40 μM) or H8 (25 μM) resulted in a loss of the protein synthesis rhythm, a suppression of the cell—cell self‐organization. Stimulation of protein kinase activity with either 0.5 or 1.0 μM phorbol 12‐miristate‐13‐acetate (PMA) or 10 μM forskolin caused the appearance of the synthetic rhythm in non‐synchronous sparse cultures under otherwise normal conditions. Inhibition of protein kinase activity with H7 resulted in signal factors, such as gangliosides and phenylephrine, failing to initiate this rhythm in sparse cultures. Activation of protein kinase activity with PMA shifted the phase pattern of the protein synthesis rhythm. Thus, according to our previous and the new data, protein kinase activity and consequently protein phosphorylation is the crucial step of sequence of processes resulting in synchronization during self‐organization of cells in producing a common rhythm in the population. The general pathway can be presented as follows: signaling of gangliosides or other calcium agonists → efflux of calcium ion from intracellular stores, with elevation of calcium concentration in the cytoplasm → activation of protein kinases → protein phosphorylation → synchronization of individual oscillations in protein synthesis rates → induction of a common rhythm throughout this population. The data have been discussed concerning similarity of the direct cell—cell communication and the cell self‐organization in cultures and in organism.
Immunoglobulin alpha heavy chain derived from human epithelial cancer cells promotes the access of S phase and growth of cancer cells
Authors: Zheng Hui , Li Ming , Liu Haidan , Ren Wei , Hu Duo‐sha , Shi Ying , Tang Ming , Cao Ya
Published: September 2006

It is generally believed that under normal conditions only B lymphocytes express immunoglobulin. Interestingly, our previous work demonstrated that epithelial cancer tissues and cancer cell lines also express Ig alpha heavy chain. So we further analyzed the potential function of cancer‐derived Ig alpha heavy chain. Here we show that blockade of cancer‐derived Ig alpha suppressed the growth and viability of cancer cells. And cancer‐derived Ig alpha promotes the malignant proliferation ability of cancer cells. Furthermore, we demonstrated that Ig alpha protein increases the access percentage of S phase from the early mitosis of synchronized cancer cells. Our findings support the important role of cancer‐derived Ig alpha as a growth promoter of cancer cells, and reveal a novel molecular mechanism for growth and proliferation of cancer cells.
Effects of small interference RNA against PTP1B and TCPTP on insulin signaling pathway in mouse liver: Evidence for non‐synergetic cooperation
Authors: Xu Jianfeng , Li Lin , Hong Jie , Huang Weida
Published: September 2006

Metabolic deregulation accompanying type II diabetes is characterized by insulin resistance in peripheral tissues (liver, muscle, and adipose), mediated by impairments in insulin receptor (IR) signaling. Two closely‐related protein tyrosine phosphatases, PTP1B and TCPTP both showed abilities to negatively regulate insulin receptor signaling. In order to test whether these two phosphatases can act synergistically, hydrodynamic injection was applied to deliver small interfering RNA (siRNA) of PTP1B and/or TCPTP to mouse liver. By measuring insulin‐sensitive reporter gene expression and plasma glucose of diabetic mice, we found siRNA of PTP1B or TCPTP alone can sensitize insulin signal transduction, but combined treatment of both siRNAs had no better effects than siRNA of PTP1B. These results suggested siRNA of PTP1B and TCPTP can strengthen insulin signaling, but their effects do not appear to be synergistic in mouse liver.
Characterization and expression of amphioxus ApoD gene encoding an archetype of vertebrate ApoD proteins⋆
Authors: Wang Lei , Zhang Shicui , Liu Zhenhui , Li Hongyan , Wang Yongjun , Jiang Shengjuan
Published: September 2006

Here we report a homologue of the apolipoprotein D gene (AmphiApoD) in amphioxus, Branchiostoma belcheri tsingtauense, the first such finding in a basal chordate cephalochordate. The main features of the protein predicted from AmphiApoD are characteristic of the apolipoprotein D. Phylogenetic analysis places AmphiApoD at the base of the phylogenetic tree, suggesting that AmphiApoD is the archetype of the vertebrate ApoD genes. Both whole mount in situ hybridization and Northern blotting and RT—PCR as well as in situ hybridization histochemistry reveal that AmphiApoD is expressed in tissues derived from mesoderm and endoderm including notochord and hind‐gut, which contrasts with the strong expression patterns of ApoD genes in the ectodermal derivatives in mammals and birds. The expression profiles of the ApoD gene may have been changed to be expressed in the endo‐mesodermal derivatives in amphioxus after the vertebrate and cephalochordate lineages diverged; alternatively, the ApoD gene may first have been expressed in the endo‐mesoderm during embryogenesis in the last common ancestor of all chordates, and subsequently came to be expressed in the ectodermal derivatives of vertebrates including mammals and birds.
vasa‐related genes and their expression in stem cells of colonial parasitic rhizocephalan barnacle Polyascus polygenea (Arthropoda: Crustacea: Cirripedia: Rhizocephala)
Authors: Shukalyuk Andrey I. , Golovnina Kseniya A. , Baiborodin Sergei I. , Gunbin Konstantin V. , Blinov Alexander G. , Isaeva Valeria V.
Published: September 2006

vasa (vas)‐related genes are members of the DEAD‐box protein family and are expressed in the germ cells of many Metazoa. We cloned vasa‐related genes (PpVLG, CpVLG) and other DEAD‐box family related genes (PpDRH1, PpDRH2, CpDRH, AtDRHr) from the colonial parasitic rhizocephalan barnacle Polyascus polygenea, the non‐colonial Clistosaccus paguri (Crustacea: Cirripedia: Rhizocephala), and the parasitic isopodan Athelgis takanoshimensis (Crustacea: Isopoda). The colonial Polyascus polygenea, a parasite of the coastal crabs Hemigrapsus sanguineus and Hemigrapsus longitarsis was used as a model object for further detailed investigations. Phylogenetic analysis suggested that PpVLG and CpVLG are closely related to vasa‐like genes of other Arthropoda. The rest of the studied genes form their own separate branch on the phylogenetic tree and have a common ancestry with the p68 and PL10 subfamilies. We suppose this group may be a new subfamily of the DEAD‐box RNA helicases that is specific for parasitic Crustacea. We found PpVLG and PpDRH1 expression products in stem cells from stolons and buds of internae, during asexual reproduction of colonial P. polygenea, and in germ cells from sexually reproducing externae, including male spermatogenic cells and female oogenic cells.
Cell surface overexpression of αvβ5 integrin impedes αvβ3‐mediated migration of the human ovarian adenocarcinoma cell line IGROV1
Authors: Maubant Sylvie , Leroy‐Dudal Johanne , Carreiras Franck , Deslandes Edwige , Duigou Françoise , Staedel Cathy , Gauduchon Pascal
Published: September 2006

Human ovarian surface epithelium and epithelial tumors express integrin αvβ5, which can interact with vitronectin. In addition, in vitro acquisition of cisplatin resistance by αvβ3‐expressing IGROV1 cells is accompanied by cell‐surface expression of integrin αvβ5. To further explore the role of αvβ5 in ovarian carcinoma cells, IGROV1 cells were stably transfected with a human β5 integrin cDNA construct, and three β5 transfectant clones were selected for the expression of αvβ5 integrin at their cell surface. Despite a delayed entry in the exponential phase of growth, β5‐transfectant cells kept a proliferation ability similar to that of parental cells, while their growth rate was hindered in the presence of an anti‐αvβ5 blocking antibody. Only simultaneous blockade of αvβ3 and αvβ5 by specific antibodies impeded the adhesion to vitronectin of β5 transfectants and of the β5‐expressing cisplatin‐resistant variant IGROV1‐R10, suggesting that the two heterodimers cooperated in the regulation of this process. Cell surface expression of αvβ5 resulted in an attenuation of αvβ3‐mediated migration on vitronectin. αvβ5 participated to migration events in the absence of exogenous growth factors only in one transfectant clone and in IGROV1‐R10 cells. Finally, the response to cisplatin was not significantly modified in β5 transfectants when compared to IGROV1 parental cells.
Expression of PTEN and Akt phosphorylation in lipopolysaccharide‐treated NIH3T3 cells
Authors: Okamura Hirohiko , Yoshida Kaya , Sasaki Eiko , Qiu Lihong , Amorim Bruna Rabelo , Morimoto Hiroyuki , Haneji Tatsuji
Published: September 2006

PTEN is a tumor suppressor gene encoding a phosphatase, and it negatively regulates cell survival mediated by the phosphoinositol 3‐kinase (PI3‐Kinase)‐Akt pathway. To elucidate PTEN expression and its effect on the PI3‐kinase‐Akt pathway in fibroblasts and macrophages, we investigated the expression of PTEN and the phosphorylation status of Akt in NIH3T3 and RAW264.7 cells treated with LPS. Phosphorylation of Akt was induced by LPS treatment in a dose‐dependent manner in RAW264.7 cells, but not in NIH3T3 cells. LPS induced the expression of PTEN in a dose and time‐dependent manner in NIH3T3 cells (0–1 μg/ml, 0–6 h). However, LPS did not stimulate PTEN expression in RAW264.7 cells. These data indicate the existence of diverse mechanisms for PTEN expression and Akt activation in fibroblasts and macrophages. RNA interference using double‐stranded RNA specific for the PTEN gene reduced both mRNA and protein levels of PTEN in NIH3T3 cells treated or not with LPS. The phosphorylation status of Akt in NIH3T3 cells stimulated with LPS did not change when the PTEN expression had been inhibited by RNA interference. The present results suggest that the up‐regulation of PTEN expression by LPS is not involved in the activation of Akt in NIH3T3 cells. PTEN expression might be involved in the diverse inflammatory responses to LPS in fibroblasts and macrophages.
High‐resolution X‐ray microtomography for three‐dimensional visualization of human stem cell muscle homing
Authors: Torrente Y. , Gavina M. , Belicchi M. , Fiori F. , Komlev V. , Bresolin N. , Rustichelli F.
Published: September 2006

In the perspective of clinical translation of stem cell research, it would be advantageous to develop new techniques to detect donor cells after transplantation to track their fate and thus better understand their role in regeneration of damaged and diseased tissues. In this study we use X‐ray computed microtomography for three‐dimensional visualization of stem cells that were labeled with magnetic nanoparticles and transplanted via intra‐arterial infusion. We show that X‐ray computed microtomography offers the possibility to detect with high definition and resolution human cells after transplantation, and opens new possibilities for both experimental stem cell research.
Compositional properties of human cDNA libraries: Practical implications
Authors: Arhondakis Stilianos , Clay Oliver , Bernardi Giorgio
Published: September 2006

The strikingly wide and bimodal gene distribution exhibited by the human genome has prompted us to study the correlations between EST‐counts (expression levels) and base composition of genes, especially since existing data are contradictory. Here we investigate how cDNA library preparation affects the GC distributions of ESTs and/or genes found in the library, and address consequences for expression studies. We observe that strongly anomalous GC distributions often indicate experimental biases or deficits during their preparation. We propose the use of compositional distributions of raw ESTs from a cDNA library, and/or of the genes they represent, as a simple and effective tool for quality control.
Palatal Implants: A New Approach for the Treatment of Obstructive Sleep Apnea
Authors: Walker Regina P. , Levine Howard L. , Hopp Martin L. , Greene David , Pang Kenny
Published: September 2006

OBJECTIVE

To evaluate the short‐term safety and efficacy of palatal implants in patients with mild and moderate obstructive sleep apnea (OSA).

STUDY DESIGN AND SETTING

A prospective, non‐randomized study conducted at 5 clinical sites. Three polyester implants were placed in the soft palate under local anesthesia during a single‐stage office procedure. Polysomnography was conducted at baseline and 90 days post‐procedure. Subjective quality of life data were collected.

RESULTS

Fifty‐three patients were evaluated; the apnea hypopnea index (AHI) decreased from 25.0 ± 13.9 to 22.0 ± 14.8 events/hour (P = 0.05). The Epworth Sleepiness Scale (ESS) decreased from 11.0 ± 5.1 to 6.9 ± 4.5 (P < 0.001), and the snore score decreased from 7.9 ± 2.1 to 4.0 ± 3.0 (P < 0.001). No serious complications occurred during the study.

CONCLUSION

Palatal implants can be an effective initial low morbidity treatment option for patients diagnosed with mild to moderate OSA.
INTERNATIONAL PUBLIC GOODS THROUGH INTEGRATED NATURAL RESOURCES MANAGEMENT RESEARCH IN CGIAR PARTNERSHIPS
Authors: HARWOOD R. R. , PLACE F. , KASSAM A. H. , GREGERSEN H. M.
Published: September 2006

The CGIAR System conducts research to produce international public goods (IPG) that are of wide applicability, creating a scientific base which speeds and broadens local adaptive development. Integrated natural resources management (INRM) research is sometimes seen to be very location specific and consequently does not lend itself readily to the production of IPGs. In this paper we analyse ways in which strategic approaches to INRM research can have broad international applicability and serve as useful foundations for the development of locally adapted technologies. The paper describes the evolution of the IPG concept within the CGIAR and elaborates on five major types of IPGs that have been generated from a varied set of recent INRM research efforts. CGIAR networks have both strengths and weaknesses in INRM research and application, with enormous differences in relative research and development capacities, responsibilities and data access of its partners, making programme process evolution critical to acceptance and participation. Many of the lessons learnt regarding challenges and corresponding IPG research approaches are relevant to designing and managing future multi-scale, multi-locational, co-ordinated INRM programmes involving broad-based partnerships to address complex environmental and livelihood problems for development.
EXPLORING FARMERS' INNOVATIVENESS: EXPERIENCES WITH THE ADAPTATION OF WATER-SAVING TECHNOLOGIES FOR SMALL-SCALE VEGETABLE PRODUCTION AROUND MARSABIT MOUNTAIN IN NORTHERN KENYA
Authors: NGUTU M. N. , RECKE H.
Published: September 2006

Over 90 % of the farmers around Marsabit Mountain, a pocket of arable land amidst a predominantly arid area in northern Kenya, are former pastoralists, unfamiliar with productive and sustainable farming technologies. This paper describes how encouraging farmer innovativeness enhanced adoption and adaptation of water-saving technologies to suit individual farmers' needs. When farmers understood the principles behind a technology they were more likely to adapt it. Both men and women farmers were most interested in increasing their available income through improved technologies, but more women than men ranked labour saving as an important attribute of a new technology. More women adopted the new technologies, but men used them on a larger area than women. The paper also shows that agricultural productivity can substantially increase even if the theoretical full potential of the recommended practices might not be achieved. It is concluded that farmers need to be exposed to new ideas in exciting and thought provoking ways to tap their innovation potential.
The Picture Archiving and Communication System: a useful tool in a case of upper oesophageal foreign body
Authors: Kulamarva G , Buckland J R , Sapare S , Pringle M B
Published: September 2006

We present a case of an oesophageal foreign body (approximately 2×2 cm) which was not seen on the initial lateral soft tissue neck X-ray but was detected following manipulation of the X-ray using the Picture Archiving and Communication System of X-ray viewing. This system gives the user much greater flexibility, including a choice of magnification and contrast.
The immunohistochemical expression of p21WAF1/Cip1 and Proliferating cell nuclear antigen in laryngeal squamous cell carcinomas
Authors: Li X , Izumaru S , Sakamoto K , Miyajima Y , Nakashima T
Published: September 2006

The purpose of this study was to assess the significance of the expression of p21WAF1/Cip1 and proliferating cell nuclear antigen (PCNA) in human laryngeal squamous cell carcinomas. Forty-eight patients (25 supraglottic, 23 glottic) who had undergone operations between 1998 and 2003 were included in this study. The Envision immunohistochemistry method was utilized to stain these tissue specimens. The results showed that the immunostaining of p21WAF1/Cip1 do not show any correlation with differentiation, N stage, metastasis, survival, recurrence or the laryngeal site of involvement. A significant inverse correlation was detected between p21WAF1/Cip1 and the T stage. In contrast, the percentage of PCNA labelled cells showed a significant correlation with the T stage, but not with other clinicopathological parameters. There were differences in the expression of p21WAF1/Cip1 and PCNA between the supraglottic and the glottic carcinomas. In conclusion, our findings suggest that p21WAF1/Cip1 and PCNA may play an important role in the progression of carcinoma of the supraglottic larynx.
Cystadenocarcinoma (papillary cystadenocarcinoma) of the submandibular gland
Authors: Harimaya A , Somekawa Y , Sasaki M , Ohuchi T
Published: September 2006

Cystadenocarcinoma (papillary cystadenocarcinoma) of the salivary gland is a rare malignant neoplasm. Major locations of this neoplasm are the parotid gland, the sublingual gland, and minor salivary glands, while occurrence in the submandibular gland is extremely rare. As far as we know, only one report, written in the French language, has been published concerning cystadenocarcinoma of the submandibular gland, but no report is available in the English language. In this report, we describe a case of cystadenocarcinoma arising from the submandibular gland of a 54-year-old male patient. The neoplasm is a low-grade carcinoma, and pre-operative examination may not show typical characteristics of malignant neoplasms. Therefore, as was true in this case, the differential diagnosis from benign lesions is sometimes difficult. This is the first report on cystadenocarcinoma of the submandibular gland in the English language and the first to show a computed tomography (CT) scan and magnetic resonance imaging (MRI) of this neoplasm in the submandibular gland.
Obliteration of the tympanomastoid cavity: long term results of the Rambo operation
Authors: Kos M-I , Chavaillaz O , Guyot J-P
Published: September 2006

Introduction: Radical mastoidectomy and tympanomastoid obliteration with fat tissue, also called the Rambo operation, is proposed to those patients suffering chronic middle-ear disease, with or without cholesteatoma, who have no useful hearing in an ear which cannot be kept dry despite all conservative treatment.

Methods: We analysed retrospectively a series of 46 patients operated upon in our department. Information recorded included the surgical indications, surgical observations, post-operative care and complications. All patients were invited to comment on their long term anatomical and functional results and to express their degree of satisfaction with the procedure.

Results: Recurrent infectious episodes were observed in seven cases. Residual cholesteatoma were observed in three cases. After treatment, these patients did not present with further complications. One case presented with multiple episodes of infection with recurrences of cholesteatoma and finally had the obliterated cavity transformed into an open cavity again. For most of the patients, in the long term (i.e. one to 23 years post-operatively (mean eight years)), the operation resulted in a dry ear, ending the need for frequent consultations to clean and disinfect diseased ears or open cavities.

Conclusion: Obliteration of the tympanomastoid cavity, as proposed by Tom Rambo, shortens considerably the post-operative care period, in comparison with canal wall down mastoidectomy, and is therefore indicated if no serviceable hearing can be expected. In the long term, the rate of complications is low and patients are satisfied.
Visualization of a high protein concentration in the cochlea of a patient with a large endolymphatic duct and sac, using three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging
Authors: Sugiura M , Naganawa S , Sato E , Nakashima T
Published: September 2006

Objective: To evaluate the inner ear of a patient with an enlarged vestibular aqueduct and acute hearing deterioration, using three-dimensional fluid-attenuated inversion recovery (3D FLAIR) magnetic resonance imaging (MRI).

Background: Three-dimensional fluid-attenuated inversion recovery MRI has been recently developed to detect haemorrhage and high concentrations of protein. Application of this method to inner-ear diseases has not been fully described.

Method: We used 3D FLAIR MRI to evaluate a patient with an enlarged vestibular aqueduct and acute hearing deterioration.

Results: On 3D FLAIR MRI, this patient had high signals in the endolymphatic duct and sac, the vestibule and the cochlea and was diagnosed as having a high protein concentration in the inner ear. These high signal areas were not detected by T1- and T2-weighted MRI.

Conclusion: This is the first published case in which a high protein concentration in the cochlea of a patient with an enlarged vestibular aqueduct was detected by 3D FLAIR MRI. These findings strongly supported the theory of the pathophysiology of hearing deterioration in patients with an enlarged vestibular aqueduct, which states that hyperosmolar fluid in the enlarged endolymphatic sac refluxes into the cochlea, resulting in damage to the hair cells. Thus, these finding may help clarify the cause of hearing deterioration in the presence of a large endolymphatic duct and sac.
Gibt es triviale (banale) Fieberzustände in der hausärztlichen Praxis?
Authors: Horn
Published: September 2006

Information, was Fieber im praktischen Alltag bedeutet. Erarbeiten einer rationalen und rationellen Abklärung zwischen «watchful waiting» und diagnostischem Übereifer (abwarten oder abklären, Priorität von Anamnese und klinischer Untersuchung). Vor- und Nachteile einer Fiebersenkung, Pandemieproblem, was nie vergessen?
Personality and Performance Anxiety Among Professional Orchestra Musicians
Authors: Langendörfer Franziska , Hodapp Volker , Kreutz Gunter , Bongard Stephan
Published: September 2006

The objective of the present study was to examine the influence of personality traits and coping strategies on performance anxiety among professional orchestra musicians. The sample consisted of 122 members of six German symphony and opera orchestras. The musicians were asked to complete questionnaires measuring various personality traits. In addition, shortly before a normal rehearsal and a public performance, they also gave details about their state-coping and their present level of performance anxiety. The latter was measured by four aspects: Lack of confidence, worry, emotionality, and physical symptoms. These aspects of performance anxiety have different patterns of predicting personality traits and the patterns also differ between the rehearsal and the performance situation. Musicians suffering from performance anxiety will try all manner of strategies before a rehearsal or performance to cope with the situation, even if not all of these strategies are appropriate for reducing performance anxiety.
A link between low‐frequency mesoscale eddy variability around Madagascar and the large‐scale Indian Ocean variability
Authors: Palastanga V. , van Leeuwen P. J. , de Ruijter W. P. M.
Published: September 2006

A connection is shown to exist between the mesoscale eddy activity around Madagascar and the large‐scale interannual variability in the Indian Ocean. We use the combined TOPEX/Poseidon‐ERS sea surface height (SSH) data for the period 1993–2003. The SSH‐fields in the Mozambique Channel and east of Madagascar exhibit a significant interannual oscillation. This is related to the arrival of large‐scale anomalies that propagate westward along 10°–15°S in response to the Indian Ocean dipole (IOD) events. Positive (negative) SSH anomalies associated to a positive (negative) IOD phase induce a shift in the intensity and position of the tropical and subtropical gyres. A weakening (strengthening) results in the intensity of the South Equatorial Current and its branches along east Madagascar. In addition, the flow through the narrows of the Mozambique Channel around 17°S increases (decreases) during periods of a stronger and northward (southward) extension of the subtropical (tropical) gyre. Interaction between the currents in the narrows and southward propagating eddies from the northern Channel leads to interannual variability in the eddy kinetic energy of the central Channel in phase with the one in the SSH‐field.
Detecting the source of Heinrich layers: An organic geochemical study
Authors: Rashid Harunur , Grosjean Emmanuelle
Published: September 2006

There are controversies regarding the origin of Heinrich layer 3 (H3), the massive ice‐rafting and meltwater event in the North Atlantic during the last glacial cycle spanning a time window between 29 and 30 kyr B.P. Some argue in favor of a Laurentide Ice Sheet source similar to other Heinrich layers, while a contending view argues for the European ice sheet source. Existing geochemical proxies such as 40Ar/39Ar, 206Pb/204Pb, or ɛNd, etc., could not be used to distinguish among various sources of ice‐rafted debris in H3 because of their low abundances, suggesting a background glacial sediment signal. In order to circumvent this problem a biomarker‐based approach is used to characterize the provenance of H layers 2, 3, and 4 and other non‐Heinrich layers. The presence of hopanes and steranes and their aromatic counterparts in the H layers is incompatible with Recent sediments and is attributed to the transportation of organic matter because of the glacial erosion of source rocks. The most diagnostic and useful signatures of this ancient organic matter in the H layers are the dominance of C34 hopanoids over C33 and the occurrence of isorenieratane along with palaerenieratane. Biomarkers signatures in H layers 2 and 3 of the Labrador Sea suggest no difference in their source. Hydrocarbon distributions suggest that these sediments were derived from the Middle to Late Ordovician and Silurian source rocks of the Hudson Bay of eastern Canada. Biomarker data of the H layer 4 from the northwest Atlantic reveal that the sediments of this layer have a similar source to the H layers in the Labrador Sea.
Simulation chamber studies on the NO3 chemistry of atmospheric aldehydes
Authors: Bossmeyer J. , Brauers T. , Richter C. , Rohrer F. , Wegener R. , Wahner A.
Published: September 2006

Absolute reaction rate studies of NO3 radicals with 4 aldehydes were performed in the atmosphere simulation chamber SAPHIR at the Research Center Jülich. Rate coefficients (ethanal: 2.6 ± 0.5, propanal: 5.8 ± 1.0, butanal: 11.9 ± 1.4, benzaldehyde: 2.2 ± 0.6; in 10−15 cm3 s−1 at 300 K) were determined from measured concentration–time profiles of aldehydes and NO3 at near ambient conditions. The values for the aliphatic aldehydes are in good agreement with the most recent recommendations (IUPAC Subcommittee on Gas Kinetic Data Evaluation for Atmospheric Chemistry: Evaluated kinetic and photochemical data for atmospheric chemistry, 2005, available at http://www.iupac-kinetic.ch.cam.ac.uk). The measured concentration‐time profiles of precursor aldehydes, NO3, NO2, and of product aldehydes were compared to model calculations based on the MCM v3 (Jenkin et al., 2003; Saunders et al., 2003). Differences between measurements and model are attributed to a major interference of the GC system to peroxyacyl nitrates. In addition modifications to the rate constants in the MCM are suggested.
Observations of non‐volcanic tremor during the northern Cascadia slow‐slip event in February 2002
Authors: Royle Gillian T. , Calvert Andrew J. , Kao Honn
Published: September 2006

We locate in the Cascadia subduction zone non‐volcanic tremors from an episodic tremor and slip event in February 2002. The tremors occurred during two 10‐day periods separated by a short lull. Tremors that occurred during the first period are broadly distributed between 10 km and 40 km depth at the southern end of Vancouver Island, and over a >50 km wide region measured normal to the margin. During the second period of tremor activity, most tremors were concentrated in a narrower zone, and many tremors occurred near the subduction megathrust at approximately 35 km depth. This relatively large number of tremors near the subduction megathrust is in contrast to the broad depth distribution of the subsequent March 2003 tremor sequence. The change in the pattern of tremor activity observed during the February 2002 sequence may indicate a change in the slow slip process, or in its migration along the margin.
Caldera types: How end‐members relate to evolutionary stages of collapse
Authors: Acocella Valerio
Published: September 2006

Currently proposed caldera types (downsag, piston, funnel, piecemeal, trapdoor) are mainly based on field evidence and are each viewed as end‐members. An overview of recent experiments on caldera formation, under different conditions, shows remarkably consistent results and suggests four experimental stages characterized by progressive subsidence. Distinctive structural features of each stage are found in many calderas, highlighting an overall consistency. The evolutionary stages adequately explain the architecture and development of the established caldera end‐members along a continuum, where one or more end‐member may correspond to a specific stage. While such a continuum is controlled by progressive subsidence, specific collapse geometries will result from secondary factors, such as roof aspect ratio, collapse symmetry and pre‐existing faults.
Detailed fault structure highlighted by finely relocated aftershocks, Arthur's Pass, New Zealand
Authors: Bannister S. , Thurber C. , Louie J.
Published: September 2006

More than 6000 aftershocks were recorded following the 1994 Arthur's Pass Mw6.7 earthquake in South Island, New Zealand. Here we relocate over 3500 of the aftershocks using double‐difference tomography to map detailed fault structures, and obtain a 3‐D model of P‐wave velocity and Vp/Vs ratio in the volume around the aftershock region. Waveform cross‐correlation methods are used to calculate high quality differential times for event pairs. Two parallel clusters in particular are very well defined after the double‐difference relocation, with a dip of ∼70–80° and ∼N60E ±10° strike. A third NW‐dipping cluster aligns very closely with one of the preferred fault planes for the mainshock, corroborating previous interpretations of the mainshock source mechanism. Results from the double‐difference tomography indicate P‐wave velocities and Vp/Vs change markedly immediately above the upper bound of the seismicity, with a Vp of 4.5 to 5.5 km/s and elevated Vp/Vs found in the top 2 km.
Processing of cloud condensation nuclei by collision‐coalescence in a mesoscale model
Authors: Mechem David B. , Robinson Paul C. , Kogan Yefim L.
Published: September 2006

The Naval Research Laboratory's Coupled Ocean‐Atmosphere Mesoscale Prediction System (COAMPS) is employed to explore the relative importance of source, sink, and transport processes in producing an accurate forecast of the aerosol‐cloud‐drizzle system. Cloud processing, defined to be the reduction of cloud condensation nuclei (CCN) via collision‐coalescence, is not uniquely related to total particle concentration, a behavior which stems from the roughly inverse dependence on cloud droplet concentration between autoconversion and accretion depletion terms. Instead, the behavior of cloud processing in COAMPS suggests relationships (scalings) based on cloud base drizzle rate (R) and cloud droplet concentration (Nc). Cloud processing is found to be correlated with drizzle, a relationship that can be represented as a power law for drizzle rates less than 0.6 mm d−1. A scaling for cloud processing based on the product of Nc and R is accurate over a wider range of drizzle rates. Results from large eddy simulation with size‐resolved microphysical processes demonstrate reasonable agreement with COAMPS and the two parameter scaling. Entrainment plays an important role in strongly modulating the mean marine boundary layer (MBL) concentration, both increasing and decreasing CCN, depending upon the entrainment velocity we and the difference between MBL and free tropospheric CCN concentrations. The importance of entrainment suggests that transport processes, especially in the vertical, play a fundamental role in the overall MBL CCN balance. In situ sources rates of CCN, taken to represent heterogeneous chemical processes and sea salt flux of submicron size particles from the ocean surface, must be unrealistically large in order to be of the same magnitude as cloud processing. Because of the prevailing importance of cloud processing and entrainment over timescales of a typical mesoscale forecast, we argue that incorporating accurate vertical aerosol profiles into the model update cycles, either from remote sensing or from global chemistry models, is more important than highly constrained local CCN source rates.
A key role for the subunit SUR2B in the preferential activation of vascular KATP channels by isoflurane
Authors: Fujita H , Ogura T , Tamagawa M , Uemura H , Sato T , Ishida A , Imamaki M , Kimura F , Miyazaki M , Nakaya H
Published: September 2006

Background and purpose:

It has been postulated that isoflurane, a volatile anaesthetic, produces vasodilatation through activation of ATP‐sensitive K+ (KATP) channels. However, there is no direct evidence for the activation of vascular KATP channels by isoflurane. This study was conducted to examine the effect of isoflurane on vascular KATP channels and compare it with that on cardiac KATP channels.

Experimental approach:

Effects of isoflurane on KATP channels were examined in aortic smooth muscle cells and cardiomyocytes of the mouse using patch clamp techniques. Effects of the anaesthetic on the KATP channels with different combinations of the inward rectifier pore subunits (Kir6.1 and Kir6.2) and sulphonylurea receptor subunits (SUR2A and SUR2B) reconstituted in a heterologous expression system were also examined.

Key results:

Isoflurane increased the coronary flow in Langendorff‐perfused mouse hearts in a concentration‐dependent manner, which was abolished by 10 μM glibenclamide. In enzymically‐dissociated aortic smooth muscle cells, isoflurane evoked a glibenclamide‐sensitive current (i.e. KATP current). In isolated mouse ventricular cells, however, isoflurane failed to evoke the KATP current unless the KATP current was preactivated by the K+ channel opener pinacidil. Although isoflurane readily activated the Kir6.1/SUR2B channels (vascular type), the volatile anesthetic could not activate the Kir6.2/SUR2A channels (cardiac type) expressed in HEK293 cells. Isoflurane activated a glibenclamide‐sensitive current in HEK293 cells expressing Kir6.2/SUR2B channels.

Conclusion and implications:

Isoflurane activates KATP channels in vascular smooth muscle cells and produces coronary vasodilation in mouse hearts. SUR2B may be important for the activation of vascular‐type KATP channels by isoflurane.

British Journal of Pharmacology (2006) 149, 573–580. doi:10.1038/sj.bjp.0706891
Inhibition by α‐Tetrahydrodeoxycorticosterone (THDOC) of Pre‐Sympathetic Parvocellular Neurones in the Paraventricular Nucleus of Rat Hypothalamus
Authors: Womack M D , Pyner S , Barrett‐Jolley R
Published: September 2006

Background and Purpose:

α‐tetrahydrodeoxycorticosterone (THDOC) is an endogenous neuroactive steroid which increases in plasma and brain concentration during stress. It has both positive and negative modulatory effects on GABA activated GABAA currents, dependent upon the dose. We investigated the effects of THDOC on spinally‐projecting “pre‐sympathetic” neurones in the parvocellular subnucleus of the hypothalamic paraventricular nucleus (PVN), to determine whether it activates or inhibits these neurones, and by what mechanism.

Experimental Approach:

Rat spinally‐projecting (parvocellular) PVN neurones were identified by retrograde labelling and the action of THDOC investigated with three modes of patch‐clamp: cell‐attached action current, whole‐cell voltage‐clamp and cell‐attached single‐channel recording.

Key Results:

In cell‐attached patch mode, parvocellular neurones fired action potentials spontaneously with an average frequency of 3.6±1.1Hz. Bath application of THDOC reduced this with an EC50 of 67nM (95% confidence limits: 54 to 84nM), Hill coefficient 0.8±0.04, n=5. In whole‐cell patch‐clamp mode, pressure ejection of GABA evoked inward currents. These were clearly GABAA currents, since they were inhibited by the GABAA receptor antagonist bicuculline, and reversed near the chloride equilibrium potential. THDOC significantly potentiated GABAA currents (1μM THDOC: 148±15% of control, n=5, p≤0.05, ANOVA). Single‐channel analysis showed no differences in conductance or corrected mean open times in the presence of 1μM THDOC.

Conclusions and Implications:

THDOC inhibited parvocellular neuronal activity without showing any evidence of the bidirectional activity demonstrated previously with cultured hypothalamic neurones. Our data are consistent with the hypothesis that THDOC acts by potentiating the post‐synaptic activity of endogenously released GABA.

British Journal of Pharmacology (2006) 149, 600–607. doi:10.1038/sj.bjp.0706911
High bandwidth data recording systems for pulsed power and laser produced plasma experiments
Authors: May M. J. , Clancy T. , Fittinghoff D. , Halvorson C. , Mills T. , Nikitin A. , Perry T. , Roberson G. P. , Smith D. , Teruya A. , Miller E. K. , Trainham C.
Published: September 2006

We present two high bandwidth data transmission and recording systems for the measurement of transient signals during pulsed power and laser produced plasmas. These systems use fiber optic cables to transmit analog data over long distances to high bandwidth digitizing oscilloscopes. One system is based on the direct modulation of a laser diode and has a bandwidth of 1.5GHz. The other system is based upon a Mach-Zehnder modulator and has a bandwidth of 12GHz, and is limited by the photoreceiver. The signals are recorded on commercial digitizing oscilloscopes that have approximately six effective bits. The transmission systems use many off-the-shelf components from the telecommunications industry and thus have a high reliability and a moderate cost. Investigation of the reduction in optical transmission of the fibers during exposure to high dose radiation will also be discussed.
Diagnosing the properties of dynamic Hohlraums with tracer spectroscopy (invited)
Authors: Apruzese J. P. , Clark R. W. , Davis J. , Sanford T. W. L. , Nash T. J. , Mock R. C. , Peterson D. L.
Published: September 2006

A dynamic Hohlraum (DH) is formed when arrays of tungsten wires driven by a high current pulse implode upon a cylindrical foam target. At impact, the wire plasma launches a radiating shock in the foam and confines the radiation. This sequence of events forms an intense, ∼200–250eV Planckian x-ray source which is a prime candidate for indirect drive inertial confinement fusion. In recent DH experiments on the 20MA Z facility, Al and MgF2 tracer layers were embedded in the cylindrical foam targets to provide K-shell lines in the keV spectral region for diagnosing the conditions of the interior Hohlraum plasma. Time-resolved K-shell spectra of both Al and Mg show mostly absorption lines. These data can be understood and quantitatively analyzed with detailed atomic and radiation transport models. The analyses show no evidence of intrinsic differences in the properties of the tops and bottoms of the Hohlraums. The interiors of the cylindrical Hohlraums are found to be hotter than the ends.
Neutral argon density profile determination by comparison of spectroscopic measurements and a collisional-radiative model (invited)
Authors: Keesee Amy M. , Scime Earl E.
Published: September 2006

Neutral atoms play important roles in non-fully-ionized plasmas. In helicon sources, neutral pumping and neutral damping of waves are poorly understood. Measurement of the spatial distribution of neutral atoms is possible with spectroscopic diagnostics such as laser-induced fluorescence (LIF) and passive emission spectroscopy. However, these measurements typically apply to an excited neutral atom state, rather than the entire neutral population. With a collisional-radiative (CR) model employing Langmuir probe measured electron parameters in argon helicon source plasmas, we have reproduced LIF and emission spectroscopy measured radial profiles for three excited neutral states. The CR model indicates a neutral depletion on axis of at least 60%. Simple calculations based on measured edge neutral pressures and peak plasma densities significantly underestimate the degree of ionization in the core of the helicon plasma.
Thomson scattering from a shock front
Authors: Reighard A. B. , Drake R. P. , Donajkowski T. , Grosskopf M. , Dannenberg K. K. , Froula D. , Glenzer S. , Ross J. S. , Edwards J.
Published: September 2006

We have obtained a Thomson scattering spectrum in the collective regime by scattering a probe beam from a shock front, in an experiment conducted at the Omega laser at the Laboratory for Laser Energetics. The probe beam was created by frequency converting a beamline at Omega to a 2ns pulse of 0.263μm light, focused with a dedicated optical focusing system. The diagnostic system included collecting optics, spectrometer, and streak camera, with a scattering angle of 101°. The target included a primary shock tube, a 20-μm-thick beryllium drive disk, 0.3-μm-thick polyimide windows mounted on a secondary tube, and a gas fill tube. Detected acoustic waves propagated parallel to the target axis. Ten laser beams irradiated the beryllium disk with 0.351μm light at 5×1014W∕cm2 for 1ns starting at to, driving a strong shock through argon gas at ρo=1mg∕cc. The 200J probe beam fired at t=19ns for 2ns, and at t=20.1ns a 0.3ns signal was detected. We attribute this signal to scattering from the shocked argon, before the density increased above critical due to radiative collapse.
Short pulse laser produced energetic electron and positron measurements
Authors: Chen Hui , Wilks Scott C. , Patel Parvesh K. , Shepherd Ronnie
Published: September 2006

Very energetic (>MeV) electrons are commonly produced from ultraintense (>1019W∕cm2) laser-solid interactions. Diagnosing these so-called hot electrons is of fundamental importance in understanding the detailed laser plasma physics present in these interactions, as well as in potential applications. Interestingly, positrons can also be produced in these interactions if the number and effective temperature of hot electrons exceed a threshold value. This additional information may help to better determine the effective electron temperature that exists in these targets. We have designed and constructed a compact spectrometer that can simultaneously measure the energy spectra of both electrons and positrons. Presented here are the principles of the spectrometer together with its experimental results obtained on the ultraintense (>1019W∕cm2) lasers at Lawrence Livermore National Laboratory and the Rutherford Appleton Laboratory Vulcan petawatt laser.