WorldWideScience

Sample records for ca3 dendritic retraction

  1. Retraction.

    Science.gov (United States)

    2016-11-01

    This article has been retracted at the request of: Editor-in-Chief and Author 'TW-37, a small-molecule inhibitor of Bcl-2, inhibits cell growth and invasion in pancreatic cancer' by Wang, Z., Song, W., Aboukameel, A., Mohammad, M., Wang, G., Banerjee, S., Kong, D., Wang, S., Sarkar, F. H. and Mohammad, R. M. The above article, published online on 4 June 2008, in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the authors, the journal Editor-in-Chief, Professor Peter Lichter, and Wiley Periodicals, Inc. A university investigation involving the first and the second-to-last author determined that several figures from another published paper were manipulated or duplicated and re-used in this paper. Therefore, the authors are retracting the paper in its entirety although they maintain that these issues did not affect the major conclusions. They apologize for any inconvenience this may have caused. Reference Wang, Z., Song, W., Aboukameel, A., Mohammad, M., Wang, G., Banerjee, S., Kong, D., Wang, S., Sarkar, F. H. and Mohammad, R. M. (2008), TW-37, a small-molecule inhibitor of Bcl-2, inhibits cell growth and invasion in pancreatic cancer. Int. J. Cancer, 123: 958-966. doi: 10.1002/ijc.23610. PMID:27534921

  2. Estrogen induces rapid decrease in dendritic thorns of CA3 pyramidal neurons in adult male rat hippocampus

    International Nuclear Information System (INIS)

    Modulation of hippocampal synaptic plasticity by estrogen has been attracting much attention. Thorns of thorny excrescences of CA3 hippocampal neurons are post-synaptic regions whose presynaptic partners are mossy fiber terminals. Here we demonstrated the rapid effect of estradiol on the density of thorns of thorny excrescences, by imaging Lucifer Yellow-injected CA3 neurons in adult male rat hippocampal slices. The application of 1 nM estradiol induced rapid decrease in the density of thorns on pyramidal neurons within 2 h. The estradiol-mediated decrease in the density of thorns was blocked by CNQX (AMPA receptor antagonist) and PD98059 (MAP kinase inhibitor), but not by MK-801 (NMDA receptor antagonist). ERα agonist PPT induced the same suppressive effect as that induced by estradiol on the density of thorns, but ERβ agonist DPN did not affect the density of thorns. Note that a 1 nM estradiol treatment did not affect the density of spines in the stratum radiatum and stratum oriens. A search for synaptic ERα was performed using purified RC-19 antibody. The localization of ERα (67 kDa) in the CA3 mossy fiber terminals and thorns was demonstrated using immunogold electron microscopy. These results imply that estradiol drives the signaling pathway including ERα and MAP kinase

  3. Retraction Notice

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    <正>Retraction:"Which lamp will be optimum to eye?Incandescent,fluorescent or LED etc"by Liang Chen and Xiao-Wei Zhang published on International Journal of Ophthalmology 2014;7(1):163-168.Authors of the above article failed to declare conflicts of interest,which violates the research ethics and moral norms.After a thorough investigation,we regret to announce that we must retract this article.We regret any adverse effects this article may have caused.

  4. Retraction notice.

    Science.gov (United States)

    2015-12-01

    The following articles have been retracted at the request of the Editors and the Publisher.After conducting a thorough investigation, SAGE found that the submitting authors of a number of papers published in the Journal of the Renin-Angiotensin Aldosterone System (JRAAS) (listed below) had supplied fabricated contact details for their nominated reviewers. The Editors accepted these papers based on the reports supplied by the individuals using these fake reviewer email accounts. After concluding that the peer review process was therefore seriously compromised, SAGE and the journal Editors have decided to retract all affected articles. ONLINE FIRST ARTICLES THESE ARTICLES WILL NOT BE PUBLISHED IN AN ISSUE: Wenzhuang Tang, Tian-Biao Zhou, and Zongpei Jiang Association of the angiotensinogen M235T gene polymorphism with risk of diabetes mellitus developing into diabetic nephropathy Journal of Renin-Angiotensin-Aldosterone System 1470320314563426, first published on December 18, 2014 doi:10.1177/1470320314563426 Tian-Biao Zhou, Hong-Yan Li, Zong-Pei Jiang, Jia-Fan Zhou, Miao-Fang Huang, and Zhi-Yang Zhou Role of renin-angiotensin-aldosterone system inhibitors in radiation nephropathy Journal of Renin-Angiotensin-Aldosterone System 1470320314563424, first published on December 18, 2014 doi:10.1177/1470320314563424 Weiqiang Zhong, Zongpei Jiang, and Tian-Biao Zhou Association between the ACE I/D gene polymorphism and T2DN susceptibility: The risk of T2DM developing into T2DN in the Asian population Journal of Renin-Angiotensin-Aldosterone System 1470320314566019, first published on January 26, 2015 doi:10.1177/1470320314566019 Tian-Biao Zhou, Xue-Feng Guo, Zongpei Jiang, and Hong-Yan Li Relationship between the ACE I/D gene polymorphism and T1DN susceptibility/risk of T1DM developing into T1DN in the Caucasian population Journal of Renin-Angiotensin-Aldosterone System 1470320314563425, first published on February 1, 2015 doi:10.1177/1470320314563425 Chun-Hua Yang and Tian

  5. Retractions in orthopaedic research

    Science.gov (United States)

    Yan, J.; MacDonald, A.; Baisi, L-P.; Evaniew, N.; Bhandari, M.

    2016-01-01

    Objectives Despite the fact that research fraud and misconduct are under scrutiny in the field of orthopaedic research, little systematic work has been done to uncover and characterise the underlying reasons for academic retractions in this field. The purpose of this study was to determine the rate of retractions and identify the reasons for retracted publications in the orthopaedic literature. Methods Two reviewers independently searched MEDLINE, EMBASE, and the Cochrane Library (1995 to current) using MeSH keyword headings and the ‘retracted’ filter. We also searched an independent website that reports and archives retracted scientific publications (www.retractionwatch.com). Two reviewers independently extracted data including reason for retraction, study type, journal impact factor, and country of origin. Results One hundred and ten retracted studies were included for data extraction. The retracted studies were published in journals with impact factors ranging from 0.000 (discontinued journals) to 13.262. In the 20-year search window, only 25 papers were retracted in the first ten years, with the remaining 85 papers retracted in the most recent decade. The most common reasons for retraction were fraudulent data (29), plagiarism (25) and duplicate publication (20). Retracted articles have been cited up to 165 times (median 6; interquartile range 2 to 19). Conclusion The rate of retractions in the orthopaedic literature is increasing, with the majority of retractions attributed to academic misconduct and fraud. Orthopaedic retractions originate from numerous journals and countries, indicating that misconduct issues are widespread. The results of this study highlight the need to address academic integrity when training the next generation of orthopaedic investigators. Cite this article: J. Yan, A. MacDonald, L-P. Baisi, N. Evaniew, M. Bhandari, M. Ghert. Retractions in orthopaedic research: A systematic review. Bone Joint Res 2016;5:263–268. DOI: 10

  6. Preputial retraction in children

    OpenAIRE

    Agarwal Abhinav; Mohta Anup; Anand Ritesh

    2005-01-01

    OBJECTIVE: The aim of the study was to assess preputial retractability in children at various ages. MATERIALS AND METHODS: Nine hundred and sixty boys attending the hospital were included in the study. Children with hypospadias or history of preputial manipulation were excluded. Preputial anatomy was studied and subjects were classified into five groups as described by Kayaba et al . RESULTS: The prepuce could not be retracted at all so as to make even the external urethral meatus visib...

  7. Preputial retraction in children

    Directory of Open Access Journals (Sweden)

    Agarwal Abhinav

    2005-01-01

    Full Text Available OBJECTIVE: The aim of the study was to assess preputial retractability in children at various ages. MATERIALS AND METHODS: Nine hundred and sixty boys attending the hospital were included in the study. Children with hypospadias or history of preputial manipulation were excluded. Preputial anatomy was studied and subjects were classified into five groups as described by Kayaba et al . RESULTS: The prepuce could not be retracted at all so as to make even the external urethral meatus visible in 61.4% children aged 0-6 months while this decreased to only 0.9% in children aged 10-12 years. At the other end of the spectrum, while prepuce could not be fully retracted in any child below 6 months, it could be done in about 60% in the age group of 10-12 years. CONCLUSION Preputial nonseparation is the major cause of preputial nonretraction in the pediatric age group. Prepuce spontaneously separates from the glans as age increases and true phimosis is rare in children. Surgical intervention should be avoided for nonseparation of prepuce.

  8. The Tie retraction syndrome.

    Science.gov (United States)

    Geerling, Gerd; Neppert, Birte; Hemmant, Bridget

    2012-12-01

    Tissue retraction is implicated in the pathogenesis of various ophthalmic disorders. Here we describe the clinical characteristics, epidemiology and pathophysiology of a form of retraction syndrome which - to the best of our knowledge - has not been reported in the ophthalmic literature so far. We have termed this condition - consisting of a slowly progressive pseudovertical shortening of tie length due to a horizontal extension of girth length - the "Tie retraction syndrome" (TRS). Other pathognomonic features include an increased tie tip to belt buckle distance and a prolapse of the subumbilical fat pad (SUFP). The syndrome has a clear male to female preponderance and shows an increasing incidence with age and income before tax. Based on a newly proposed grading scheme we discuss and illustrate the diagnosis as well as the medical and surgical management options of this abundant, but often undiagnosed condition. The authors have no explanation for the apparent lack of awareness for this widely preponderant syndrome and its severe cosmetically disfiguring potential. We thus would like to invite all fellow colleagues with expertise in the field to comment or present their views. PMID:23088329

  9. Retractable storage lug

    International Nuclear Information System (INIS)

    Inspecting and refueling a nuclear reactor requires the removal and storage of various reactor components until the job is completed. In particular, current practice calls for an indexing fixture to be stored separately from a previously withdrawn plenum assembly. In the present invention the indexing fixture may be stacked directly upon the plenum assembly, thereby resulting in a savings in both floor storage space and downtime. The indexing fixture is equipped with a plurality of rotatable and retractable storage lugs, each equipped with a rotatable and slidable weight-cylinder assembly in coaxial relationship with a pivoted support beam. The weight-cylinder assembly and support beam are connected together by a lockable channel, groove and pin arrangement. Provision is allowed for remote activation of the lug

  10. Notice of retraction

    Directory of Open Access Journals (Sweden)

    Tunali S

    2010-08-01

    Full Text Available Dear Colleagues,It has recently been brought to my attention that the following case report by Padeyappanavar et al., which was published online in the International Journal of Anatomical Variations (IJAV on February 23rd, 2010 (Padeyappanavar KV, Kazi AK, Nagaleekar A, Kulkarni D, Kulkarni U, Hukkeri V. Elongated styloid process – report of three cases. International Journal of Anatomical Variations. 2010; 3: 30–32. [1], has already been published in the Journal of the Anatomical Society of India in June 2008 [2], and in the Al Ameen Journal of Medical Sciences in January 2010 [3]. The manuscript has been submitted to IJAV in July 30th, 2009, and accepted for publication in January 22nd, 2010. It is obvious that the manuscript has been submitted to IJAV one year later to its initial publication in the Journal of the Anatomical Society of India. The editorial office of IJAV has confirmed that this case report by Padeyappanavar et al. was a duplicate publication, violating the publication agreement of IJAV. The most important condition of submission of a manuscript for publication is explicit declaration of the authors that the paper has not been published or is not under consideration for publication in any other journal. As such this manuscript represents a severe abuse of the scientific publishing system.We immediately contacted the corresponding author (Dr. Kiran V. Padeyappanavar, Department of Anatomy, Belgaum Institute of Medical Sciences, India. E-mail: dr.kiranvp@gmail.com. Unfortunately, we could not get a satisfactory or logical explanation. Therefore, we hereby notice our readers that the paper by Padeyappanavar et al. [1] has been retracted.The institutions of the authors will also be advised via this notice of retraction.We deeply apologize to our readers and the international scientific community for this inconvenience that was totally occurred out of IJAV, and respectfully announce to the scientific world

  11. Effect of nitric oxide synthase inhibition on long-term potentiation at associational-commissural and mossy fibre synapses on CA3 pyramidal neurones.

    OpenAIRE

    Nicolarakis, P. J.; Lin, Y Q; Bennett, M. R.

    1994-01-01

    1. The sensitivity of long-term potentiation (LTP) to nitric oxide synthase (NOS) inhibition was determined for two synaptic input systems onto CA3 pyramidal neurones the LTP of which display differential sensitivity to N-methyl-D-aspartate (NMDA) receptor antagonists: the fimbrial input which activates the associational-commissural synapses on the distal apical dendrites and the mossy fibre input which synapses on the proximal apical dendrites of CA3 pyramidal neurones. 2. Following high-fre...

  12. On Retractable S-Acts

    Institute of Scientific and Technical Information of China (English)

    R.KHOSRAVI

    2012-01-01

    In this paper we introduce a class of right S-acts called retractable S-acts which are right S-acts with homomorphisms into their all subacts.We also give some classifications of monoids by comparing such acts with flatness properties.

  13. Corticotomy-assisted retraction: An outcome assessment

    Directory of Open Access Journals (Sweden)

    S Vijayashri Sakthi

    2014-01-01

    Conclusion: The rate of retraction with study group was twice as faster when compared to the control group, accelerating during the first 2 months of retraction. There was better anchorage control with the undecorticated molar segment during the retraction period but was found to increase as time advanced.

  14. Lightweight extendable and retractable pole

    International Nuclear Information System (INIS)

    A lightweight extendable and retractable telescopic pole is disclosed comprising a plurality of non-metallic telescoping cylinders with sliding and sealing surfaces between the cylinders, a first plug member on the upper end of the smallest cylinder, and a second plug member on the lower end of the largest cylinder, whereby fluid pressure admitted to the largest cylinder will cause the telescoping cylinders to slide relative to one another causing the pole to extend. An elastomeric member connects the first plug member with one of the intermediate cylinders to urge the cylinders back into a collapsed position when the fluid pressure in the cylinders is vented. Annular elastomer members are provided which seal one cylinder to another when the pole is fully extended and further serve to provide a cushion to prevent damage to the cylinders when the pole is urged back into its retractable position by the elastomeric members and the venting of the pressure. A value mechanism associated with the pole is provided to admit a fluid under pressure to the interior of the telescoping cylinders of the pole while pressurizing a pressure relief port having an opening larger than the inlet port in a closed position whereby removal of the pressure on the relief port will cause the relief port to open to quickly lower the pressure in the interior of the telescoping cylinders to thereby assist in the rapid retraction of the extended pole. 18 figs

  15. Clinical characteristics of the eardrum retraction pocket

    Directory of Open Access Journals (Sweden)

    Ješić Snežana

    2003-01-01

    Full Text Available Development of the eardrum retraction pocket, as pathologic finding, depends on Eustachian tube dysfunction, onset of the middle ear infection and site of development of retraction on the eardrum. The study is aimed at: 1. Determining the incidence of eardrum retraction pocket and cholesteatoma within it, as well as at the degree of eardrum retraction; 2. Determining of association between eardrum retraction pocket and changes of the eardrum mucosaand parstensa of the tympanic membrane; 3. Determining of onset and intensity of the bone destruction in eardrum retraction pocket; 4. Examining of Eustachian tube function based on time of mucocilliary transport according to the type of the eardrum retraction pocket. The study is based on the retrospective analysis of the results obtained from the patients treated at the Institute of Oto-Rhino-Laryngology and Maxillofacial Surgery Clinical Centre of Serbia in Belgrade for the diagnosis of the chronic suppurative otitis who underwent otosurgical procedures during the six-year period, from 1996-2001. In our series of 540 patients subjected to otosurgical treatment, the incidence of the retraction pocket of the eardrum was 11.23%. Onset of more severe degree of eardrum retraction was most frequent in the attic. Cholesteatoma was detected in 82.2% of patients of the group with the attic-retraction pocket of the eardrum, as well as in 25% of patients of the group of tensa-sinus retraction pocket of the eardrum. Atrophic changes of the tympanic membrane pars tensa were detected in almost all tensa-sinus retraction pockets of the eardrum. Approximately one half of the attic-retraction pockets of the eardrum were accompanied by eardrum atrophy. Bone destruction of the auditory ossicles was limited to the long process of incus and superior structures of stapes. Time of the mucocilliary transport was significantly longer (p<0.01 in attic-retraction pocket of the eardrum than in tensa-sinus retraction pocket of

  16. Retraction

    OpenAIRE

    Hill, Tim

    2016-01-01

    Gu J, Sun R, Shen S, Yu Z. The influence of TLR4 agonist lipopolysaccharides on hepatocellular carcinoma cells and the feasibility of its application in treating liver cancer. Onco Targets Ther. 2015;8:2215–2225.The first author (Junsheng Gu) created an email address for Dr Yu without permission and used figures from a previously published paper: Lin A, Wang G, Zhao H, et al. TLR4 signaling promotes a COX-2/PGE2/STAT3 positive feedback loop in hepatocellular carcinoma (HCC) cells. O...

  17. Frobenius groups and retract rationality

    CERN Document Server

    Kang, Ming-chang

    2012-01-01

    Let $k$ be any field, $G$ be a finite group acting on the rational function field $k(x_g:g\\in G)$ by $h\\cdot x_g=x_{hg}$ for any $h,g\\in G$. Define $k(G)=k(x_g:g\\in G)^G$. Noether's problem asks whether $k(G)$ is rational (= purely transcendental) over $k$. A weaker notion, retract rationality introduced by Saltman, is also very useful for the study of Noether's problem. We prove that, if $G$ is a Frobenius group with abelian Frobenius kernel, then $k(G)$ is retract $k$-rational for any field $k$ satisfying some mild conditions. As an application, we show that, for any algebraic number field $k$, for any Frobenius group $G$ with Frobenius complement isomorphic to $SL_2(\\bm{F}_5)$, there is a Galois extension field $K$ over $k$ whose Galois group is isomorphic to $G$, i.e. the inverse Galois problem is valid for the pair $(G,k)$. The same result is true for any non-solvable Frobenius group if $k(\\zeta_8)$ is a cyclic extension of $k$.

  18. The Problem of Retraction in Critical Discussion

    NARCIS (Netherlands)

    Krabbe, Erik C. W.

    2001-01-01

    In many contexts a retraction of commitment is frowned upon. For instance, it is not appreciated, generally, if one withdraws a promise or denies an earlier statement. Critical discussion, too, can easily be disrupted by retractions, if these occur too frequently and at critical points. But on the o

  19. Corticotomy-assisted retraction: An outcome assessment

    OpenAIRE

    S Vijayashri Sakthi; Vikraman, B; V R Shobana; S Kavitha Iyer; N R Krishnaswamy

    2014-01-01

    Background: To assess the efficiency and treatment outcome of patients treated with corticotomy-assisted en-masse orthodontic retraction as compared with the en-masse retraction without corticotomy. Materials and Methods: Forty adult patients with bimaxillary protrusion requiring correction of bidental proclination constituted the sample. The study group consisted of 22 patients (male 11, female 11) willing to undergo surgery to reduce the duration of their orthodontic treatment and 18 pa...

  20. A retractable barb needle for drug darts

    Directory of Open Access Journals (Sweden)

    G.L. van Rooyen

    1973-07-01

    Full Text Available The mechanism and action of a new retractable barbneedle for drug darts are described. This dart needle is particularly successful in obviating unnecessary flight reactions andtrauma in darted animals, and facilitates the complete injection of the drug dose before the barb is retracted and the dart is dislogded from the animal. The whole process is completed within a few seconds and the expended dart can usually be retrieved in the immediate vicinity where the animal was darted.

  1. Neuronal migration and its disorders affecting the CA3 region

    Directory of Open Access Journals (Sweden)

    Richard eBelvindrah

    2014-03-01

    Full Text Available In this review, we focus on CA3 neuronal migration disorders in the rodent. We begin by introducing the main steps of hippocampal development, and we summarize characteristic hippocampal malformations in human. We then describe various mouse mutants showing structural hippocampal defects. Notably, genes identified in human cortical neuronal migration disorders consistently give rise to a CA3 phenotype when mutated in the mouse. We successively describe their molecular, physiological and behavioral phenotypes that together contribute to a better understanding of CA3-dependent functions. We finally discuss potential factors underlying the CA3 vulnerability revealed by these mouse mutants and that may also contribute to other human neurological and psychiatric disorders.

  2. A Comprehensive Survey of Retracted Articles from the Scholarly Literature

    OpenAIRE

    Grieneisen, Michael L.; Zhang, Minghua

    2012-01-01

    Background The number of retracted scholarly articles has risen precipitously in recent years. Past surveys of the retracted literature each limited their scope to articles in PubMed, though many retracted articles are not indexed in PubMed. To understand the scope and characteristics of retracted articles across the full spectrum of scholarly disciplines, we surveyed 42 of the largest bibliographic databases for major scholarly fields and publisher websites to identify retracted articles. Th...

  3. Topological stability through extremely tame retractions

    DEFF Research Database (Denmark)

    Feragen, Aasa

    2012-01-01

    Suppose that F : (Rn ×Rd, 0)¿(Rp ×Rd, 0) is a smoothly stable, Rd-level preserving germ which unfolds f : (Rn, 0)¿(Rp, 0); then f is smoothly stable if and only if we can find a pair of smooth retractions r : (Rn+d, 0)¿(Rn, 0) and s : (Rp+d, 0)¿(Rp, 0) such that f ¿ r = s ¿ F . Unfortunately, we do...... not know whether f will be topologically stable if we can find a pair of continuous retractions r and s. The class of extremely tame (E-tame) retractions, introduced by du Plessis and Wall, are defined by their nice geometric properties, which are sufficient to ensure that f is topologically stable....... In this article, we present the E-tame retractions and their relation with topological stability, survey recent results by the author concerning their construction, and illustrate the use of our techniques by constructing E-tame retractions for certain germs belonging to the E- and Z-series of...

  4. Behavioral Functions of the CA3 Subregion of the Hippocampus

    Science.gov (United States)

    Kesner, Raymond P.

    2007-01-01

    From a behavioral perspective, the CA3a,b subregion of the hippocampus plays an important role in the encoding of new spatial information within short-term memory with a duration of seconds and minutes. This can easily be observed in tasks that require rapid encoding, novelty detection, one-trial short-term or working memory, and one-trial cued…

  5. Proof Systems for Retracts in Simply Typed Lambda Calculus

    OpenAIRE

    Stirling, Colin,

    2013-01-01

    This paper concerns retracts in simply typed lambda calculus assuming βη-equality. We provide a simple tableau proof system which characterises when a type is a retract of another type and which leads to an exponential decision procedure.

  6. Stochastic description of pilus retraction dynamics

    Science.gov (United States)

    Lindén, Martin; Johansson, Emil; Jonsson, Ann-Beth

    2005-03-01

    Motility of certain gram-negative bacteria is mediated by retraction of type IV pili surface filaments, which are essential for infectivity. Type IV pili are helical filaments with 4 nm periodicity and 5 subunits per turn. The retraction is powered by a strong molecular motor protein, PilT, producing very high forces in excess of 100 pN[1]. One possible explanation for the high forces are that several ATP are hydrolyzed to retract each subunit.We consider a widely used class of discrete hopping models, which has been used to describe well-known motor proteins such as kinesin[2] and myosin[3]. The model describes recent experimental measurements[1] on Neisseria gonorrhoeae well, and makes several interesting predictions for the randomness of the retraction dynamics.1. Maier et al, PNAS 101:10961 (2004)2. M. E. Fisher and A. B. Kolomeisky, PNAS 98:7748 (2001)3. A. B. Kolomeisky and M. E. Fisher, Biophys. J. 84:1650 (2003)

  7. Radiation therapy apparatus having retractable beam stopper

    International Nuclear Information System (INIS)

    This invention relates to a radiation therapy apparatus which utilized a linear translation mechanism for positioning a beam stopper. An apparatus is described wherein the beam stopper is pivotally attached to the therapy machine with an associated drive motor in such a way that the beam stopper retracts linearly

  8. Place Cell Rate Remapping by CA3 Recurrent Collaterals

    Science.gov (United States)

    Solstad, Trygve; Yousif, Hosam N.; Sejnowski, Terrence J.

    2014-01-01

    Episodic-like memory is thought to be supported by attractor dynamics in the hippocampus. A possible neural substrate for this memory mechanism is rate remapping, in which the spatial map of place cells encodes contextual information through firing rate variability. To test whether memories are stored as multimodal attractors in populations of place cells, recent experiments morphed one familiar context into another while observing the responses of CA3 cell ensembles. Average population activity in CA3 was reported to transition gradually rather than abruptly from one familiar context to the next, suggesting a lack of attractive forces associated with the two stored representations. On the other hand, individual CA3 cells showed a mix of gradual and abrupt transitions at different points along the morph sequence, and some displayed hysteresis which is a signature of attractor dynamics. To understand whether these seemingly conflicting results are commensurate with attractor network theory, we developed a neural network model of the CA3 with attractors for both position and discrete contexts. We found that for memories stored in overlapping neural ensembles within a single spatial map, position-dependent context attractors made transitions at different points along the morph sequence. Smooth transition curves arose from averaging across the population, while a heterogeneous set of responses was observed on the single unit level. In contrast, orthogonal memories led to abrupt and coherent transitions on both population and single unit levels as experimentally observed when remapping between two independent spatial maps. Strong recurrent feedback entailed a hysteretic effect on the network which diminished with the amount of overlap in the stored memories. These results suggest that context-dependent memory can be supported by overlapping local attractors within a spatial map of CA3 place cells. Similar mechanisms for context-dependent memory may also be found in

  9. Place cell rate remapping by CA3 recurrent collaterals.

    Directory of Open Access Journals (Sweden)

    Trygve Solstad

    2014-06-01

    Full Text Available Episodic-like memory is thought to be supported by attractor dynamics in the hippocampus. A possible neural substrate for this memory mechanism is rate remapping, in which the spatial map of place cells encodes contextual information through firing rate variability. To test whether memories are stored as multimodal attractors in populations of place cells, recent experiments morphed one familiar context into another while observing the responses of CA3 cell ensembles. Average population activity in CA3 was reported to transition gradually rather than abruptly from one familiar context to the next, suggesting a lack of attractive forces associated with the two stored representations. On the other hand, individual CA3 cells showed a mix of gradual and abrupt transitions at different points along the morph sequence, and some displayed hysteresis which is a signature of attractor dynamics. To understand whether these seemingly conflicting results are commensurate with attractor network theory, we developed a neural network model of the CA3 with attractors for both position and discrete contexts. We found that for memories stored in overlapping neural ensembles within a single spatial map, position-dependent context attractors made transitions at different points along the morph sequence. Smooth transition curves arose from averaging across the population, while a heterogeneous set of responses was observed on the single unit level. In contrast, orthogonal memories led to abrupt and coherent transitions on both population and single unit levels as experimentally observed when remapping between two independent spatial maps. Strong recurrent feedback entailed a hysteretic effect on the network which diminished with the amount of overlap in the stored memories. These results suggest that context-dependent memory can be supported by overlapping local attractors within a spatial map of CA3 place cells. Similar mechanisms for context-dependent memory may

  10. Fuzzy Retractions of Fuzzy Open Flat Robertson-Walker Space

    OpenAIRE

    A. E. El-Ahmady; A. S. Al-Luhaybi

    2013-01-01

    Our aim in the present paper is to introduce and study new types of fuzzy retractions of fuzzy open flat Robertson-Walker model. New types of the fuzzy deformation retracts of model are obtained. The relations between the fuzzy foldings and the fuzzy deformation retracts of model are deduced. Types of fuzzy minimal retractions are also presented. New types of homotopy maps are deduced. New types of conditional fuzzy folding are presented. Some commutative diagrams are obtained.

  11. Effect of retraction materials on gingival health: A histopathological study

    Directory of Open Access Journals (Sweden)

    Phatale Sushma

    2010-01-01

    Full Text Available Background: Gingival retraction methods are used in dentistry for impressions of subgingival crown margins, such as, mechanical, chemical, chemicomechanical, and surgical. These methods may injure the gingival sulcular epithelium. Hence, the present study is carried out to evaluate the effect of different retraction materials, such as, Expasyl, Magic Foam Cord, and impregnated retraction cord on the gingival sulcular epithelium. Materials and Methods: This study included 30 cases of bilateral premolar extraction patients with Loe and Silness gingival index zero. Retraction materials were kept in the dry, isolated labial gingival sulcus for the required time. The retraction materials were removed by rinsing with water. Retracted gingiva of 2 - 3 mm from the gingival margin along with the tooth was extracted and the decalcified sections were microscopically studied. Data analysis: Data were analyzed by applying the chi-square test. Results: This study showed better results with retraction paste as compared to the retraction cord, and there was a significant association between retraction materials and the relative degree of injury to the sulcular epithelium. Conclusion: There is a significant association between retraction materials and gingival sulcular epithelium. It can be stated that impregnated retraction cord, may be used commonly but it needs proper tissue manipulation and is technique sensitive. Newly advanced material in the form of retraction paste like Expasyl or Magic Foam Cord was found to be better than cord as assessed histologically, it respects periodontium.

  12. A comprehensive survey of retracted articles from the scholarly literature.

    Directory of Open Access Journals (Sweden)

    Michael L Grieneisen

    Full Text Available BACKGROUND: The number of retracted scholarly articles has risen precipitously in recent years. Past surveys of the retracted literature each limited their scope to articles in PubMed, though many retracted articles are not indexed in PubMed. To understand the scope and characteristics of retracted articles across the full spectrum of scholarly disciplines, we surveyed 42 of the largest bibliographic databases for major scholarly fields and publisher websites to identify retracted articles. This study examines various trends among them. RESULTS: We found, 4,449 scholarly publications retracted from 1928-2011. Unlike Math, Physics, Engineering and Social Sciences, the percentages of retractions in Medicine, Life Science and Chemistry exceeded their percentages among Web of Science (WoS records. Retractions due to alleged publishing misconduct (47% outnumbered those due to alleged research misconduct (20% or questionable data/interpretations (42%. This total exceeds 100% since multiple justifications were listed in some retraction notices. Retraction/WoS record ratios vary among author affiliation countries. Though widespread, only miniscule percentages of publications for individual years, countries, journals, or disciplines have been retracted. Fifteen prolific individuals accounted for more than half of all retractions due to alleged research misconduct, and strongly influenced all retraction characteristics. The number of articles retracted per year increased by a factor of 19.06 from 2001 to 2010, though excluding repeat offenders and adjusting for growth of the published literature decreases it to a factor of 11.36. CONCLUSIONS: Retracted articles occur across the full spectrum of scholarly disciplines. Most retracted articles do not contain flawed data; and the authors of most retracted articles have not been accused of research misconduct. Despite recent increases, the proportion of published scholarly literature affected by retraction

  13. Prominent hippocampal CA3 gene expression profile in neurocognitive aging

    OpenAIRE

    Haberman, Rebecca P.; Colantuoni, Carlo; Stocker, Amy M.; Schmidt, Alexandra C.; Pedersen, Jan T.; Gallagher, Michela

    2009-01-01

    Research in aging laboratory animals has characterized physiological and cellular alterations in medial temporal lobe structures, particularly the hippocampus, that are central to age-related memory deficits. The current study compares molecular alterations across hippocampal subregions in a rat model that closely mirrors individual differences in neurocognitive features of aging humans, including both impaired memory and preserved function. Using mRNA profiling of the CA1, CA3 and dentate gy...

  14. High pressure studies in Ca3Ru2O7

    International Nuclear Information System (INIS)

    The bilayer ruthenate Ca3Ru2O7 undergoes first a magnetic transition (TN=56 K) and then a structural transition (TS= 48 K) on cooling. Most of the Fermi surface is gapped out at low temperature, leading to a very low carrier density and small Fermi surface pockets. Pressure suppresses both TN and TS and, for p>3.5 GPa, induces a third low temperature state, which has been known to be robust up to at least 7.5 GPa. A detailed investigation of the unusual low temperature states of Ca3Ru2O7 across the pressure-temperature-field phase diagram requires reliable access to hydrostatic pressures up to and beyond 10 GPa. We apply lithographic patterning and sputtering processes to anvil pressure cells in order to produce complex but robust lead patterns, which are integrated into the anvil surface. Patterns include multi-turn coils as well as eight-lead configurations for resistivity measurements. Resistivity data in Ca3Ru2O7 is presented, which indicates that the high pressure ordered state is fully suppressed at pc ≅9.5 GPa. Beyond pc, the in-plane resistivity follows a T5/3 power-law down to below 1 K, suggesting ferromagnetic quantum criticality.

  15. Lower incisor retraction with a modified corticotomy.

    Science.gov (United States)

    Germeç, Derya; Giray, Bahadir; Kocadereli, Ilken; Enacar, Ayhan

    2006-09-01

    This case report demonstrates the orthodontic treatment facilitated with a new conservative corticotomy technique to shorten the treatment time during lower incisor retraction. The patient was a 22-year-old woman with protrusive profile, severe anterior crowding, an anterior crossbite, and Class III dental relationship. Orthodontic treatment consisted of the extraction of four first premolars with maximum anchorage. A modified corticotomy technique, in which the lingual vertical and subapical horizontal cuts were eliminated, was combined with orthodontic therapy for the retraction of the lower anterior teeth. Corticotomy-facilitated orthodontics dramatically reduced the treatment time without any adverse effects on the periodontium and the vitality of the teeth. The main advantages of this modified corticotomy technique were the elimination of the lingual cuts and flap, the reduction of surgery time, and minimum discomfort to the patient. At the end of active orthodontic therapy, balanced occlusion and facial esthetics were achieved. PMID:17029527

  16. Ratchet model for type IV pilus retraction

    Science.gov (United States)

    Lindén, Martin; Tuohimaa, Tomi; Jonsson, Ann-Beth; Wallin, Mats

    2004-03-01

    Type IV pilus rectraction is required for twitching motility in a wide range of bacteriae, including Neisseria gonorrhoeae, Myxococcus xanthus and Pseudomonas aeruginosa. The mechanism of retraction is believed to be filament disassembly mediated by PilT, a member of the AAA family of motor proteins. Recent laser tweezer measurements of the force-velocity relation of PilT in N. gonorrhoeae, reveal that single PilT complexes generate forces of over 100 pN. We assume that PilT forms a cyclic ATPase surrounding the base of the pilus and formulate a model of retraction in terms of coupled flashing ratchets. We obtain a force-velocity relation by numerical simulation of the model which is in qualitative agreement with the experimental results.

  17. Fluctuations in type IV pilus retraction

    CERN Document Server

    Linden, M; Jonsson, A B; Wallin, M; Linden, Martin; Johansson, Emil; Jonsson, Ann-Beth; Wallin, Mats

    2005-01-01

    The type IV pilus retraction motor is found in many important bacterial pathogens. It is the strongest known linear motor protein and is required for bacterial infectivity. We characterize the dynamics of type IV pilus retraction in terms of a stochastic chemical reaction model. We find that a two state model can describe the experimental force velocity relation and qualitative dependence of ATP concentration. The results indicate that the dynamics is limited by an ATP-dependent step at low load and a force-dependent step at high load, and that at least one step is effectively irreversible in the measured range of forces. The irreversible nature of the sub-step(s) lead to interesting predictions for future experiments: We find different parameterizations with mathematically identical force velocity relations but different fluctuations (diffusion constant). We also find a longer elementary step compared to an earlier analysis, which agrees better with known facts about the structure of the pilus filament and e...

  18. Noninvasive measurement of eye retraction during blinking

    OpenAIRE

    Mas Candela, David; Doménech Amigot, Begoña; Espinosa Tomás, Julián; Pérez Rodríguez, Jorge; Hernández Poveda, Consuelo; Illueca Contri, Carlos

    2010-01-01

    We present a noninvasive technique for high-speed measuring of eye retraction and eyelid position during blinking. The anterior chamber of the eye is illuminated by the slit lamp of a biomicroscope and eye dynamics during a blinking sequence are captured with a high-speed camera working at 500 frames per second. Digital image processing allows quantitative analysis of cornea and eyelid positions during the closing and opening phases of the blinking process. Our method allows simultaneous meas...

  19. Platelets and fibrin strands during clot retraction.

    Science.gov (United States)

    Morgenstern, E; Korell, U; Richter, J

    1984-03-15

    The ultrastructure of platelet fibrin contacts (PFC) and the course of the strands was investigated in serial sections of retracted clots with the help of specimen tilting. We found after retraction in a test tube as well as under isometric conditions in the resonance thrombograph, after HARTERT, an uniform type of PFC. The side to side contact between platelet surface and fibrin strands displayed a 15 nm wide space which was bridged of 10 - 30 nm by filamentary structure. In each case the direction of the fibrin strands changed on contact with the platelet surface (bend). These bends recurred if the adhering strands ran over a longer distance on the platelet surface. The bends can be explained by non-directional movement of the platelets or of their pseudopodia. Microfilaments (actomyosin) which run straight in pseudopodia and often also twisted in the platelet body support this assumption. The described mechanism - contact of the thrombin activated platelets with fibrin strands and simultaneous nondirectional movement of the platelets which bind further sections of the adhering strands to their surface - would provide a more satisfactory explanation for the retraction of the clot to 1/10 of its original volume. PMID:6539004

  20. Coincidence detection of convergent perforant path and mossy fibre inputs by CA3 interneurons.

    Science.gov (United States)

    Calixto, Eduardo; Galván, Emilio J; Card, J Patrick; Barrionuevo, Germán

    2008-06-01

    We performed whole-cell recordings from CA3 s. radiatum (R) and s. lacunosum-moleculare (L-M) interneurons in hippocampal slices to examine the temporal aspects of summation of converging perforant path (PP) and mossy fibre (MF) inputs. PP EPSPs were evoked from the s. lacunosum-moleculare in area CA1. MF EPSPs were evoked from the medial extent of the suprapyramidal blade of the dentate gyrus. Summation was strongly supralinear when examining PP EPSP with MF EPSP in a heterosynaptic pair at the 10 ms ISI, and linear to sublinear at longer ISIs. This pattern of nonlinearities suggests that R and L-M interneurons act as coincidence detectors for input from PP and MF. Summation at all ISIs was linear in voltage clamp mode demonstrating that nonlinearities were generated by postsynaptic voltage-dependent conductances. Supralinearity was not detected when the first EPSP in the pair was replaced by a simulated EPSP injected into the soma, suggesting that the conductances underlying the EPSP boosting were located in distal dendrites. Supralinearity was selectively eliminated with either Ni2+ (30 microm), mibefradil (10 microm) or nimodipine (15 microm), but was unaffected by QX-314. This pharmacological profile indicates that supralinearity is due to recruitment of dendritic T-type Ca2+channels by the first subthreshold EPSP in the pair. Results with the hyperpolarization-activated (Ih) channel blocker ZD 7288 (50 microm) revealed that Ih restricted the time course of supralinearity for coincidently summed EPSPs, and promoted linear to sublinear summation for asynchronous EPSPs. We conclude that coincidence detection results from the counterbalanced activation of T-type Ca2+ channels and inactivation of Ih. PMID:18388134

  1. Spatial Phosphoprotein Profiling Reveals a Compartmentalized Extracellular Signal-regulated Kinase Switch Governing Neurite Growth and Retraction

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yingchun; Yang, Feng; Fu, Yi; Huang, Xiahe; Wang, Wei; Jiang, Xining; Gritsenko, Marina A.; Zhao, Rui; Monroe, Matthew E.; Pertz, Olivier C.; Purvine, Samuel O.; Orton, Daniel J.; Jacobs, Jon M.; Camp, David G.; Smith, Richard D.; Klemke, Richard L.

    2011-05-20

    Abstract - Brain development and spinal cord regeneration require neurite sprouting and growth cone navigation in response to extension and collapsing factors present in the extracellular environment. These external guidance cues control neurite growth cone extension and retraction processes through intracellular protein phosphorylation of numerous cytoskeletal, adhesion, and polarity complex signaling proteins. However, the complex kinase/substrate signaling networks that mediate neuritogenesis have not been investigated. Here, we compare the neurite phosphoproteome under growth and retraction conditions using neurite purification methodology combined with mass spectrometry. More than 4000 non-redundant phosphorylation sites from 1883 proteins have been annotated and mapped to signaling pathways that control kinase/phosphatase networks, cytoskeleton remodeling, and axon/dendrite specification. Comprehensive informatics and functional studies revealed a compartmentalized ERK activation/deactivation cytoskeletal switch that governs neurite growth and retraction, respectively. Our findings provide the first system-wide analysis of the phosphoprotein signaling networks that enable neurite growth and retraction and reveal an important molecular switch that governs neuritogenesis.

  2. Simulation of dendritic growth reveals necessary and sufficient parameters to describe the shapes of dendritic trees

    Science.gov (United States)

    Trottier, Olivier; Ganguly, Sujoy; Bowne-Anderson, Hugo; Liang, Xin; Howard, Jonathon

    For the last 120 years, the development of neuronal shapes has been of great interest to the scientific community. Over the last 30 years, significant work has been done on the molecular processes responsible for dendritic development. In our ongoing research, we use the class IV sensory neurons of the Drosophila melanogaster larva as a model system to understand the growth of dendritic arbors. Our main goal is to elucidate the mechanisms that the neuron uses to determine the shape of its dendritic tree. We have observed the development of the class IV neuron's dendritic tree in the larval stage and have concluded that morphogenesis is defined by 3 distinct processes: 1) branch growth, 2) branching and 3) branch retraction. As the first step towards understanding dendritic growth, we have implemented these three processes in a computational model. Our simulations are able to reproduce the branch length distribution, number of branches and fractal dimension of the class IV neurons for a small range of parameters.

  3. Magnetocapacitance in Ca3CoMnO6

    Science.gov (United States)

    Kaushik, S. D.; Rayaprol, S.; Saha, J.; Mohapatra, N.; Siruguri, V.; Babu, P. D.; Patnaik, S.

    2011-04-01

    Magnetocapacitance (MC) measurements—that is, measuring capacitance as a function of temperature at constant magnetic field—has been carried out on a quasi-1D compound, Ca3CoMnO6. MC reveals the presence of a magnetodielectric effect (MDE), which in turn signals the presence of magnetoelectric coupling below the magnetic ordering temperature, TN ( = 15 K). We also observed the sign reversal of the MDE as the temperature increased from 3 to 20 K. The MDE is positive at 3 K and negative between 3 and 15 K, and it saturates to a near zero value above 15 K. The sign change of the MDE is explained in terms the spin-pair correlation of neighboring spins of Co/Mn at a given applied magnetic field H. A negative MDE signifies antiferromagnetic ordering, and a positive MDE signifies ferromagnetic/paramagnetic ordering. Neutron diffraction study reveals changes in the magnetic structure in the temperature range of 2 to 10 K. The present work brings out the possible correlation between the magnetic structure and the dielectric properties of Ca3CoMnO6.

  4. 强可收缩半群%Strongly Retractable Semigroups

    Institute of Scientific and Technical Information of China (English)

    喻秉钧

    2000-01-01

    A semigroup S is called strongly retractable, if each of its subsemigroups is aretract of S. In this paper, strongly retractable groups, strongly retractable completelysimple semigroups, strongly retractable semilattices and strongly retractable regularsemigroups are successively characterized and finally a structure theorem for generalstrongly retractable semigroups is given.%称半群S强可收缩,若S的每个子半群都是它的一个缩回.本文逐次刻划了强可收缩的群、完全单半群、强可收缩的半格及正则半群的结构,在此基础上给出了任意强可收缩半群的结构定理.

  5. CORRECTION OF ALAR RETRACTION USING VARIOUS TECHNIQUES: A CASE SERIES

    Directory of Open Access Journals (Sweden)

    Dinesh

    2015-11-01

    Full Text Available Alar retraction is one of the common problems seen in both primary and secondary rhinoplasty. Multiple techniques of varying complexity have been described to treat this common and challenging problem.(1,4 The presently used techniques are associated with scar and potential formation of crust. Thus, we attempted to overcome these shortcomings by using new grafting techniques to correct alar retraction. In this article, we describe the simplest way of correcting alar retraction by using an alar projection graft.

  6. Fixed Simplex Property for Retractable Complexes

    Directory of Open Access Journals (Sweden)

    Zapart Anna

    2010-01-01

    Full Text Available Abstract Retractable complexes are defined in this paper. It is proved that they have the fixed simplex property for simplicial maps. This implies the theorem of Wallace and the theorem of Rival and Nowakowski for finite trees: every simplicial map transforming vertices of a tree into itself has a fixed vertex or a fixed edge. This also implies the Hell and Nešetřil theorem: any endomorphism of a dismantlable graph fixes some clique. Properties of recursively contractible complexes are examined.

  7. Study of Semi-projective Retractable Modules

    Institute of Scientific and Technical Information of China (English)

    A.Haghany; M.R.Vedadi

    2007-01-01

    For a semi-projective retractable module MR with endomorphism ring S,we prove u.dim MR = u.dim Ss,and find necessary and sufficient conditions on M in order that S be respectively semiprime,right nonsingular,finitely cogenerated,cocyclic,or weakly co-Hopfian.Precise descriptions of the right singular ideal of S and the socle of M are given,and in addition if S is a semiprime ring,it is shown that MR is FI-extending if and only if Ss is FI-extending.

  8. An adjunctive minor surgical procedure for increased rate of retraction

    Directory of Open Access Journals (Sweden)

    Prabhakar Krishnan

    2013-01-01

    Full Text Available Introduction: Orthodontic treatment is based on the principle that if prolonged pressure is applied to the tooth, tooth movement will occur as the bone around the tooth re-models. In this study osteotomy of buccal alveolar plate and undermining of interseptal bone was performed at premolar extraction site and rate of en-masse retraction and canine retraction was evaluated. Materials and Methods: Patients between the age of 18 and 25 years, requiring retraction of anterior teeth are selected for the study. Osteotomy with undermining of interseptal bone at the extraction site was performed. The procedure was performed on all four quadrants. Results: The average retraction in the maxillary arch was 0.98 mm/quadrant in 3 weeks, i.e., a total retraction of 5.89 mm in a span of 9 weeks. The average retraction in the mandibular arch was 0.96 mm/quadrant in 3 weeks, i.e., a total retraction of 5.75 mm in a span of 9 weeks. Conclusion: This method of achieving faster en masse retraction immediately after extraction definitely reduced the initial retraction time. We recommend that such procedure must be carried out with appropriate anchorage conservation methods.

  9. Hepatic capsular retraction: spectrum of diagnosis at MRI

    International Nuclear Information System (INIS)

    Hepatic capsular retraction is an imaging feature that deserves the attention of the radiologist. Hepatic capsular retraction is associated with a number of hepatic lesions, benign or malignant, treated or untreated. The purpose of this pictorial review is to discuss the most common benign and malignant hepatic lesions associated with this feature with an emphasis on magnetic resonance imaging (MRI)

  10. Stress-induced remodeling of hippocampal CA3 pyramidal neurons.

    Science.gov (United States)

    McEwen, Bruce S

    2016-08-15

    The discovery of steroid hormone receptors in brain regions that mediate virtually every aspect of brain function has broadened the definition of 'neuroendocrinology' to include the reciprocal communication between the brain and the body via hormonal and neural pathways. The brain is the central organ of stress and adaptation to stress because it perceives and determines what is threatening, as well as determining the behavioral and physiological responses to the stressor. The adult and developing brain possess remarkable structural and functional plasticity in response to stress, including neurogenesis leading to neuronal replacement, dendritic remodeling, and synapse turnover. Stress causes an imbalance of neural circuitry subserving cognition, decision-making, anxiety and mood that can alter expression of those behaviors and behavioral states. The two Brain Research papers noted in this review played an important role in triggering these advances. This article is part of a Special Issue entitled SI:50th Anniversary Issue. PMID:26740399

  11. Ablation of NMDA receptors enhances the excitability of hippocampal CA3 neurons.

    Directory of Open Access Journals (Sweden)

    Fumiaki Fukushima

    Full Text Available Synchronized discharges in the hippocampal CA3 recurrent network are supposed to underlie network oscillations, memory formation and seizure generation. In the hippocampal CA3 network, NMDA receptors are abundant at the recurrent synapses but scarce at the mossy fiber synapses. We generated mutant mice in which NMDA receptors were abolished in hippocampal CA3 pyramidal neurons by postnatal day 14. The histological and cytological organizations of the hippocampal CA3 region were indistinguishable between control and mutant mice. We found that mutant mice lacking NMDA receptors selectively in CA3 pyramidal neurons became more susceptible to kainate-induced seizures. Consistently, mutant mice showed characteristic large EEG spikes associated with multiple unit activities (MUA, suggesting enhanced synchronous firing of CA3 neurons. The electrophysiological balance between fast excitatory and inhibitory synaptic transmission was comparable between control and mutant pyramidal neurons in the hippocampal CA3 region, while the NMDA receptor-slow AHP coupling was diminished in the mutant neurons. In the adult brain, inducible ablation of NMDA receptors in the hippocampal CA3 region by the viral expression vector for Cre recombinase also induced similar large EEG spikes. Furthermore, pharmacological blockade of CA3 NMDA receptors enhanced the susceptibility to kainate-induced seizures. These results raise an intriguing possibility that hippocampal CA3 NMDA receptors may suppress the excitability of the recurrent network as a whole in vivo by restricting synchronous firing of CA3 neurons.

  12. Mnemonic Functions for Nonlinear Dendritic Integration in Hippocampal Pyramidal Circuits.

    Science.gov (United States)

    Kaifosh, Patrick; Losonczy, Attila

    2016-05-01

    We present a model for neural circuit mechanisms underlying hippocampal memory. Central to this model are nonlinear interactions between anatomically and functionally segregated inputs onto dendrites of pyramidal cells in hippocampal areas CA3 and CA1. We study the consequences of such interactions using model neurons in which somatic burst-firing and synaptic plasticity are controlled by conjunctive processing of these separately integrated input pathways. We find that nonlinear dendritic input processing enhances the model's capacity to store and retrieve large numbers of similar memories. During memory encoding, CA3 stores heavily decorrelated engrams to prevent interference between similar memories, while CA1 pairs these engrams with information-rich memory representations that will later provide meaningful output signals during memory recall. While maintaining mathematical tractability, this model brings theoretical study of memory operations closer to the hippocampal circuit's anatomical and physiological properties, thus providing a framework for future experimental and theoretical study of hippocampal function. PMID:27146266

  13. Signal Propagation in Oblique Dendrites of CA1 Pyramidal Cells

    OpenAIRE

    Migliore, Michele; Ferrante, Michele; Ascoli, Giorgio A.

    2005-01-01

    The electrophysiological properties of the oblique branches of CA1 pyramidal neurons are largely unknown and very difficult to investigate experimentally. These relatively thin dendrites make up the majority of the apical tree surface area and constitute the main target of Schaffer collateral axons from CA3. Their electrogenic properties might have an important role in defining the computational functions of CA1 neurons. It is thus important to determine if and to what extent the back- and fo...

  14. Temporal Dynamics of Acute Stress-Induced Dendritic Remodeling in Medial Prefrontal Cortex and the Protective Effect of Desipramine

    DEFF Research Database (Denmark)

    Nava, Nicoletta; Treccani, Giulia; Alabsi, Abdelrahman;

    2015-01-01

    days after stress. Acute stress produced increased spine density and decreased cofilin phosphorylation at 1 day, paralleled with dendritic retraction. An overall shift in spine population was observed at 1 day, resulting in a stress-induced increase in small spines. Significant atrophy of apical...

  15. Spiraling eutectic dendrites

    OpenAIRE

    Pusztai, Tamás; Rátkai, László; Szállás, Attila; Gránásy, László

    2013-01-01

    Eutectic dendrites forming in a model ternary system have been studied using the phase-field theory. The eutectic and one-phase dendrites have similar forms, and the tip radius scales with the interface free energy as for one-phase dendrites. The steady-state eutectic patterns appearing on these two-phase dendrites include concentric rings, and single- to multiarm spirals, of which the fluctuations choose, a stochastic phenomenon characterized by a peaked probability distribution. The number ...

  16. 强可收缩半群%Strongly Retractable Semigroups

    Institute of Scientific and Technical Information of China (English)

    喻秉钧

    2002-01-01

    A semigroup S is called strongly retractable, if each of its subsemigroups is a retract of S. In this paper, strongly retractable groups, strongly retractable completely simple semigroups, strongly retractable semilattices and strongly retractable regular semigroups are successively characterized and finally a structure theorem for general strongly retractable semigroups is given.%设S为半群,H为S的子半群,称H是S的一个缩回,若存在满同态φ:S→H满足φ|H=1H(H上的恒等映射),称半群S是强可收缩的,若S的每个子半群都是S的一个缩回.首先证明了群G为强可收缩半群的充要条件为G是一族初等Abel群的限制直积,接着得到完全单半群S强可收缩的充要条件是SG×(I×Λ),其中G为强可收缩群,I×Λ是矩形带.还证明了一个半格是强可收缩半群的充要条件是它为局部有限树.在这些结论的基础上最后得到一个半群是强可收缩半群的完整刻划.

  17. Changes in synaptic plasticity and expression of glutamate receptor subunits in the CA1 and CA3 areas of the hippocampus after transient global ischemia.

    Science.gov (United States)

    Han, Xin-Jia; Shi, Zhong-Shan; Xia, Luo-Xing; Zhu, Li-Hui; Zeng, Ling; Nie, Jun-Hua; Xu, Zao-Cheng; Ruan, Yi-Wen

    2016-07-01

    Excess glutamate release from the presynaptic membrane has been thought to be the major cause of ischemic neuronal death. Although both CA1 and CA3 pyramidal neurons receive presynaptic glutamate input, transient cerebral ischemia induces CA1 neurons to die while CA3 neurons remain relatively intact. This suggests that changes in the properties of pyramidal cells may be the main cause related to ischemic neuronal death. Our previous studies have shown that the densities of dendritic spines and asymmetric synapses in the CA1 area are increased at 12h and 24h after ischemia. In the present study, we investigated changes in synaptic structures in the CA3 area and compared the expression of glutamate receptors in the CA1 and CA3 hippocampal regions of rats after ischemia. Our results demonstrated that the NR2B/NR2A ratio became larger after ischemia although the expression of both the NR2B subunit (activation of apoptotic pathway) and NR2A subunit (activation of survival pathway) decreased in the CA1 area from 6h to 48h after reperfusion. Furthermore, expression of the GluR2 subunit (calcium impermeable) of the AMPA receptor class significantly decreased while the GluR1 subunit (calcium permeable) remained unchanged at the same examined reperfusion times, which subsequently caused an increase in the GluR1/GluR2 ratio. Despite these notable differences in subunit expression, there were no obvious changes in the density of synapses or expression of NMDAR and AMPAR subunits in the CA3 area after ischemia. These results suggest that delayed CA1 neuronal death may be related to the dramatic fluctuation in the synaptic structure and relative upregulation of NR2B and GluR1 subunits induced by transient global ischemia. PMID:27090818

  18. Computability of Homology for Compact Absolute Neighbourhood Retracts

    OpenAIRE

    Collins, Pieter; Contributed Papers

    2009-01-01

    In this note we discuss the information needed to compute the homology groups of a topological space. We argue that the natural class of spaces to consider are the compact absolute neighbourhood retracts, since for these spaces the homology groups are finite. We show that we need to specify both a function which defines a retraction from a neighbourhood of the space in the Hilbert cube to the space itself, and a sufficiently fine over-approximation of the set. However, neither the retraction ...

  19. X-ray absorption and x-ray magnetic dichroism study on Ca3CoRhO6 and Ca3FeRhO6

    Science.gov (United States)

    Burnus, T.; Hu, Z.; Wu, Hua; Cezar, J. C.; Niitaka, S.; Takagi, H.; Chang, C. F.; Brookes, N. B.; Lin, H.-J.; Jang, L. Y.; Tanaka, A.; Liang, K. S.; Chen, C. T.; Tjeng, L. H.

    2008-05-01

    By using x-ray absorption spectroscopy at the RhL2,3 , CoL2,3 , and FeL2,3 edges, we find a valence state of Co2+/Rh4+ in Ca3CoRhO6 and of Fe3+/Rh3+ in Ca3FeRhO6 . X-ray magnetic circular dichroism spectroscopy at the CoL2,3 edge of Ca3CoRhO6 reveals a giant orbital moment of about 1.7μB , which can be attributed to the occupation of the minority-spin d0d2 orbital state of the high-spin Co2+ (3d7) ions in trigonal prismatic coordination. This active role of the spin-orbit coupling explains the strong magnetocrystalline anisotropy and Ising-type magnetism of Ca3CoRhO6 .

  20. Structural aspects of calcium ion transport in Ca3(VO4)2 and Ca3-xNd2x/3(VO4)2 solid solutions

    International Nuclear Information System (INIS)

    Experimental data on electric conductivity dependence on temperature in the range of 750-1400 K for Ca3(VO4)2, Ca9Nd(VO4)7 and solid solutions Ca3-xNd2x/3(VO4)2 (0≤x≤3/7) are presented. It is ascertained that conductivity value in the solid solutions decreases essentially with increase in neodymium concentration. In Ca3(VO4)2 and Ca9Nd(VO4)7 phase transitions at 1383 and 1198 K have been detected. On the basis of the experimental data on conductivity and analysis of polyhedrons of whitlockite-like structure of Ca3(VO4)2 possible ways of calcium cations movement in the structure are discussed and substantiated

  1. Torque control during lingual anterior retraction without posterior appliances

    OpenAIRE

    Mo, Sung-Seo; Kim, Seong-Hun; Sung, Sang-Jin; Chung, Kyu-Rhim; Chun, Yun-Sic; Kook, Yoon-Ah; Nelson, Gerald

    2013-01-01

    Objective To evaluate the factors that affect torque control during anterior retraction when utilizing the C-retractor with a palatal miniplate as an exclusive source of anchorage without posterior appliances. Methods The C-retractor was modeled using a 3-dimensional beam element (0.9-mm-diameter stainless-steel wire) attached to mesh bonding pads. Various vertical heights and 2 attachment positions for the lingual anterior retraction hooks (LARHs) were evaluated. A force of 200 g was applied...

  2. K(Ca)2 and k(ca)3 channels in learning and memory processes, and neurodegeneration.

    Science.gov (United States)

    Kuiper, Els F E; Nelemans, Ad; Luiten, Paul; Nijholt, Ingrid; Dolga, Amalia; Eisel, Uli

    2012-01-01

    Calcium-activated potassium (K(Ca)) channels are present throughout the central nervous system as well as many peripheral tissues. Activation of K(Ca) channels contribute to maintenance of the neuronal membrane potential and was shown to underlie the afterhyperpolarization (AHP) that regulates action potential firing and limits the firing frequency of repetitive action potentials. Different subtypes of K(Ca) channels were anticipated on the basis of their physiological and pharmacological profiles, and cloning revealed two well defined but phylogenetic distantly related groups of channels. The group subject of this review includes both the small conductance K(Ca)2 channels (K(Ca)2.1, K(Ca)2.2, and K(Ca)2.3) and the intermediate-conductance (K(Ca)3.1) channel. These channels are activated by submicromolar intracellular Ca(2+) concentrations and are voltage independent. Of all K(Ca) channels only the K(Ca)2 channels can be potently but differentially blocked by the bee-venom apamin. In the past few years modulation of K(Ca) channel activation revealed new roles for K(Ca)2 channels in controlling dendritic excitability, synaptic functioning, and synaptic plasticity. Furthermore, K(Ca)2 channels appeared to be involved in neurodegeneration, and learning and memory processes. In this review, we focus on the role of K(Ca)2 and K(Ca)3 channels in these latter mechanisms with emphasis on learning and memory, Alzheimer's disease and on the interplay between neuroinflammation and different neurotransmitters/neuromodulators, their signaling components and K(Ca) channel activation. PMID:22701424

  3. X-ray absorption and x-ray magnetic dichroism study on Ca3CoRhO6 and Ca3FeRhO6

    OpenAIRE

    Burnus, T.; Z. Hu; Wu, Hua; Cezar, J. C.; Niitaka, S.; Takagi, H.; Chang, C. F.; Brookes, N. B.; Lin, H. -J.; Jang, L. Y.; Tanaka, A.; Liang, K. S.; Chen, C. T.; Tjeng, L. H.

    2008-01-01

    Using x-ray absorption spectroscopy at the Rh-L_2,3, Co-L_2,3, and Fe-L_2,3 edges, we find a valence state of Co^2+/Rh^4+ in Ca3CoRhO6 and of Fe^3+/Rh^3+ in Ca3FeRhO6. X-ray magnetic circular dichroism spectroscopy at the Co-L_2,3 edge of Ca3CoRhO6 reveals a giant orbital moment of about 1.7mu_B, which can be attributed to the occupation of the minority-spin d_0d_2 orbital state of the high-spin Co^2+ (3d^7) ions in trigonal prismatic coordination. This active role of the spin-orbit coupling ...

  4. Globally shed wakes for three distinct retracting foil geometries

    Science.gov (United States)

    Steele, Stephanie; Triantafyllou, Michael

    2015-11-01

    In quickly retracting foils at an angle of attack, the boundary layer vorticity along with the added mass energy is immediately and globally shed from the body into the surrounding fluid. The deposited vorticity quickly reforms into lasting vortex structures, which could be used for purposes such as manipulating or exploiting the produced flow structures by additional bodies in the fluid. The globally shed wake thus entrains the added mass energy provided by the initially moving body, reflected by the value of the circulation left in the wake. In studying experimentally as well as numerically this phenomenon, we find that the three different tested geometries leave behind distinct wakes. Retracting a square-ended foil is undesirable because the deposited wake is complicated by three-dimensional ring vorticity effects. Retracting a tapered, streamlined-tipped foil is also undesirable because the shape-changing aspect of the foil geometry actually induces energy recovery back to the retracting foil, leaving a less energetic globally shed wake. Finally, a retracting hollow foil geometry avoids both of these detrimental effects, leaving relatively simple, yet energetic, vortex structures in the wake.

  5. A Multi-dimensional Investigation of the Effects of Publication Retraction on Scholarly Impact

    CERN Document Server

    Shuai, Xin; Rollins, Jason; Custis, Tonya; Schilder, Frank; Edmunds, Mathilda

    2016-01-01

    Over the past few decades, the rate of publication retractions has increased dramatically in academia. In this study, we investigate retractions from a quantitative perspective, aiming to answer two fundamental questions. One, how do retractions influence the scholarly impact of retracted papers, authors, and institutions? Two, does this influence propagate to the wider academic community through scholarly associations? Specifically, we analyzed a set of retracted articles indexed in Thomson Reuters Web of Science (WoS), and ran multiple experiments to compare changes in scholarly impact against a control set of non-retracted articles, authors, and institutions. We further applied the Granger Causality test to investigate whether different scientific topics are dynamically affected by retracted papers occurring within those topics. Our results show two key findings: first, the scholarly impact of retracted papers and authors significantly decreases after retraction, and the most severe impact decrease correla...

  6. Retractable tool bit having slider type catch mechanism

    Science.gov (United States)

    Voellmer, George M.

    1992-12-01

    A retractable tool bit assembly utilized in connection with a robotic gripper type end-effector is presented. The apparatus includes one or more spring loaded nestable or telescoping tubular sections together with a catch mechanism for capturing and holding the toll, such as an allen key, in its retracted position. The innermost tubular section includes a threshold cap and engages and holds the tool. The catch mechanism consists of a slider type mechanism located adjacent a relatively larger outer base section and includes means for engaging a conically or mushroom shaped rear end portion of the tool when the telescoping sections are moved to a retracted or parked position. The catch mechanism is released upon actuation of a rotary tool drive motor coupled to a circular mount and which holds the base section. When released all the telescoping sections including the tool extends fully outward to a use position.

  7. The Retraction Penalty: Evidence from the Web of Science

    OpenAIRE

    Susan Feng Lu; Ginger Zhe Jin; Brian Uzzi; Benjamin Jones

    2013-01-01

    Scientific articles are retracted at increasing rates, with the highest rates among top journals. Here we show that a single retraction triggers citation losses through an author's prior body of work. Compared to closely-matched control papers, citations fall by an average of 6.9% per year for each prior publication. These chain reactions are sustained on authors' papers (a) published up to a decade earlier and (b) connected within the authors' own citation network by up to 4 degrees of separ...

  8. Limits of fuzzy retractions of fuzzy hyperspheres and their foldings

    OpenAIRE

    A. E. El-Ahmady

    2006-01-01

    This article introduces the types of fuzzy retractions of fuzzy hyperspheres $ \\tilde{S}^n\\subset R^{n+1} $ and the corresponding induced fuzzy retractions of the two fuzzy systems $ \\bigcup \\overline{\\tilde{S}}^n $, $ \\bigcup \\underline{\\tilde{S}}^n $ when the fuzzification is regular or irregular. Also, the fuzzy folding of fuzzy hyperspheres $ \\tilde{S}^n $ into itself and the induces two chains of fuzzy folding of $ \\bigcup \\overline{\\tilde{S}}^n $, $ \\bigcup \\underline{\\tilde{S}}^n $. Th...

  9. Frequency dependence of CA3 spike phase response arising from h-current properties

    Directory of Open Access Journals (Sweden)

    Hyun Jae Jang

    2013-12-01

    Full Text Available The phase of firing of hippocampal neurons during theta oscillations encodes spatial information. Moreover, the spike phase response to synaptic inputs in individual cells depends on the expression of the hyperpolarisation-activated mixed cation current (Ih, which differs between CA3 and CA1 pyramidal neurons. Here, we compared the phase response of these two cell types, as well as their intrinsic membrane properties. We found that both CA3 and CA1 pyramidal neurons show a voltage sag in response to negative current steps but that this voltage sag is significantly smaller in CA3 cells. Moreover, CA3 pyramidal neurons have less prominent resonance properties compared to CA1 pyramidal neurons. This is consistent with differential expression of Ih by the two cell types. Despite their distinct intrinsic membrane properties, both CA3 and CA1 pyramidal neurons displayed bidirectional spike phase control by excitatory conductance inputs during theta oscillations. In particular, excitatory inputs delivered at the descending phase of a dynamic clamp-induced membrane potential oscillation delayed the subsequent spike by nearly 50 mrad. The effect was shown to be mediated by Ih and was counteracted by increasing inhibitory conductance driving the membrane potential oscillation. Using our experimental data to feed a computational model, we showed that differences in Ih between CA3 and CA1 pyramidal neurons could predict frequency-dependent differences in phase response properties between these cell types. We confirmed experimentally such frequency-dependent spike phase control in CA3 neurons. Therefore, a decrease in theta frequency, which is observed in intact animals during novelty, might switch the CA3 spike phase response from unidirectional to bidirectional and thereby promote encoding of the new context.

  10. Jumlah Sel Piramidal CA3 Hipokampus Tikus Putih Jantan pada Berbagai Model Stres Kerja Kronik

    OpenAIRE

    Fitranto Arjadi; Sri Kadarsih Soejono; Lientje Setyawati Maurits; Mulyoto Pangestu

    2014-01-01

    Prolonged and chronic exposure to stress leads to the loss of neurons at the CA3 (cornu ammonis) hippocampus region and spatial memory deficits. The aim of this study was to study the number of CA3 pyramidal cells in albino rats that were exposed to chronic stress of works model consisting of paradoxical sleep deprivation (PSD), immobilization, and foot shock stresses. The method applied was the post-test only method with control group experimental design using completed randomized design (CR...

  11. A signature of attractor dynamics in the CA3 region of the hippocampus.

    Directory of Open Access Journals (Sweden)

    César Rennó-Costa

    2014-05-01

    Full Text Available The notion of attractor networks is the leading hypothesis for how associative memories are stored and recalled. A defining anatomical feature of such networks is excitatory recurrent connections. These "attract" the firing pattern of the network to a stored pattern, even when the external input is incomplete (pattern completion. The CA3 region of the hippocampus has been postulated to be such an attractor network; however, the experimental evidence has been ambiguous, leading to the suggestion that CA3 is not an attractor network. In order to resolve this controversy and to better understand how CA3 functions, we simulated CA3 and its input structures. In our simulation, we could reproduce critical experimental results and establish the criteria for identifying attractor properties. Notably, under conditions in which there is continuous input, the output should be "attracted" to a stored pattern. However, contrary to previous expectations, as a pattern is gradually "morphed" from one stored pattern to another, a sharp transition between output patterns is not expected. The observed firing patterns of CA3 meet these criteria and can be quantitatively accounted for by our model. Notably, as morphing proceeds, the activity pattern in the dentate gyrus changes; in contrast, the activity pattern in the downstream CA3 network is attracted to a stored pattern and thus undergoes little change. We furthermore show that other aspects of the observed firing patterns can be explained by learning that occurs during behavioral testing. The CA3 thus displays both the learning and recall signatures of an attractor network. These observations, taken together with existing anatomical and behavioral evidence, make the strong case that CA3 constructs associative memories based on attractor dynamics.

  12. SNAP-25 in hippocampal CA3 region is required for long-term memory formation

    International Nuclear Information System (INIS)

    SNAP-25 is a synaptosomal protein of 25 kDa, a key component of synaptic vesicle-docking/fusion machinery, and plays a critical role in exocytosis and neurotransmitter release. We previously reported that SNAP-25 in the hippocampal CA1 region is involved in consolidation of contextual fear memory and water-maze spatial memory (Hou et al. European J Neuroscience, 20: 1593-1603, 2004). SNAP-25 is expressed not only in the CA1 region, but also in the CA3 region, and the SNAP-25 mRNA level in the CA3 region is higher than in the CA1 region. Here, we provide evidence that SNAP-25 in the CA3 region is also involved in learning/memory. Intra-CA3 infusion of SNAP-25 antisense oligonucleotide impaired both long-term contextual fear memory and water-maze spatial memory, with short-term memory intact. Furthermore, the SNAP-25 antisense oligonucleotide suppressed the long-term potentiation (LTP) of field excitatory post-synaptic potential (fEPSP) in the mossy-fiber pathway (DG-CA3 pathway), with no effect on paired-pulse facilitation of the fEPSP. These results are consistent with the notion that SNAP-25 in the hippocampal CA3 region is required for long-term memory formation

  13. The nature of spin trimer in Ca3Cu2Ni(PO4)4

    International Nuclear Information System (INIS)

    The nature of spin trimer and 3d spin dynamics in Ca3Cu2Ni(PO4)4 was studied using 31P NMR measurements. This material is obtained replacing one of the Cu ions by a Ni ion in one dimensional spin trimer compound Ca3Cu3(PO4)4. NMR spectrum suggests the presence of two types of magnetically inequivalent phosphorous atoms as in the parent compound. This finding reveals the presence of only one type of trimer viz. Cu2-Cu1-Cu2 rather than three types viz., Cu2-Cu1-Cu2, Cu2-Cu1-Ni and Ni-Cu1-Ni as suggested from neutron scattering. Hence the ground state of Ca3Cu2Ni(PO4)4 appears to be a quintet. The present finding also explains the magnetic susceptibility behavior showing no indication of the reduction of net spin of a trimer in Ca3Cu2Ni(PO4)4, as expected for JNi-Cu = - 0.85 meV compared to JCu-Cu = - 4.74 meV, reported from neutron scattering. The spin lattice relaxation rate suggests that the three magnon mediated scattering process, dominant in Ca3Cu3(PO4)4, is reduced in Ca3Cu2Ni(PO4)4.

  14. Recurrent synapses and circuits in the CA3 region of the hippocampus: an associative network.

    Directory of Open Access Journals (Sweden)

    Richard eMiles

    2014-01-01

    Full Text Available In the CA3 region of the hippocampus, pyramidal cells excite other pyramidal cells and interneurons. The axons of CA3 pyramidal cells spread throughout most of the region to form an associative network. These connections were first drawn by Cajal and Lorente de No. Their physiological properties were explored to understand epileptiform discharges generated in the region. Synapses between pairs of pyramidal cells involve one or few release sites and are weaker than connections made by mossy fibres on CA3 pyramidal cells. Synapses with interneurons are rather effective, as needed to control unchecked excitation. We examine contributions of recurrent synapses to epileptiform synchrony, to the genesis of sharp waves in the CA3 region and to population oscillations at theta and gamma frequencies. Recurrent connections in CA3, as other associative cortices, have a lower connectivity spread over a larger area than in primary sensory cortices. This sparse, but wide-ranging connectivity serves the functions of an associative network, including acquisition of neuronal representations as activity in groups of CA3 cells and completion involving the recall from partial cues of these ensemble firing patterns.

  15. Prospective study of tympanic membrane retraction, hearing loss, and multifrequency tympanometry.

    Science.gov (United States)

    Li, Y; Hunter, L L; Margolis, R H; Levine, S C; Lindgren, B; Daly, K; Giebink, G S

    1999-11-01

    Tympanic membrane retraction is a significant sequela of OME and has been linked clinically to atelectasis, ossicular erosion, and cholesteatoma. We investigated important factors for prediction of tympanic membrane retraction in a prospective study of 112 children. After 4 to 6 years of follow-up, 12% of ears had pars tensa retraction without atrophy, and 28% had various degrees of retraction with atrophy. Mild pars flaccida retraction was present in 23%, and severe pars flaccida retraction was present in 12%. Retraction severity was related to hearing level and multifrequency tympanometry. Three factors were significantly related to retraction severity: type of tube, male sex, and percent of visits in the second year with abnormal tympanograms. This study shows that type of tube was the most important factor in long-term outcome after tympanostomy tube treatment of OME. PMID:10547462

  16. Dendritic Morphology of Hippocampal and Amygdalar Neurons in Adolescent Mice Is Resilient to Genetic Differences in Stress Reactivity

    NARCIS (Netherlands)

    Pillai, Anup G.; de Jong, Danielle; Kanatsou, Sofia; Krugers, Harm; Knapman, Alana; Heinzmann, Jan-Michael; Holsboer, Florian; Landgraf, Rainer; Joels, Marian; Touma, Chadi

    2012-01-01

    Many studies have shown that chronic stress or corticosterone over-exposure in rodents leads to extensive dendritic remodeling, particularly of principal neurons in the CA3 hippocampal area and the basolateral amygdala. We here investigated to what extent genetic predisposition of mice to high versu

  17. Quasi-retractive representation of solution sets to stochastic inclusions

    Directory of Open Access Journals (Sweden)

    Michal Kisielewicz

    1997-01-01

    Full Text Available Continuous dependence and retraction properties of solution sets to stochastic inclusions xt−xs∈∫stFτ(xτdτ+∫stGτ(xτdωτ+∫st∫ℝnHτ,r(xτv˜(dτ,dr are considered.

  18. Head of Human Genome Project Retracts 5 Journal Articles.

    Science.gov (United States)

    Haworth, Karla

    1996-01-01

    Five published leukemia studies have been retracted by the director of the Human Genome Project because they were based on falsified data from a graduate student, although some of the conclusions are still supported. Inconsistencies were discovered by a peer reviewer and were also found in the student's other work. (MSE)

  19. Ergodic Retractions for Families of Asymptotically Nonexpansive Mappings

    Directory of Open Access Journals (Sweden)

    Saeidi Shahram

    2010-01-01

    Full Text Available We prove some theorems for the existence of ergodic retractions onto the set of common fixed points of a family of asymptotically nonexpansive mappings. Our results extend corresponding results of Benavides and Ramírez (2001, and Li and Sims (2002.

  20. Presynaptic size of associational/commissural CA3 synapses is controlled by fibroblast growth factor 22 in adult mice.

    Science.gov (United States)

    Pasaoglu, Taliha; Schikorski, Thomas

    2016-02-01

    Associational/commissural CA3-CA3 synapses define the recurrent CA3 network that generates the input to CA1 pyramidal neurons. We quantified the fine structure of excitatory synapses in the stratum radiatum of the CA3d area in adult wild type (WT) and fibroblast growth factor 22 knock-out (FGF22KO) mice by using serial 3D electron microscopy. WT excitatory CA3 synapses are rather small yet range 10 fold in size. Spine size, however, was small and uniform and did not correlate with the size of the synaptic junction. To reveal mechanisms that regulate presynaptic structure, we investigated the role of FGF22, a target-derived signal specific for the distal part of area CA3 (CA3d). In adult FGF22KO mice, postsynaptic properties of associational CA3 synapses were unaltered. Presynaptically, the number of synaptic vesicles (SVs), the bouton volume, and the number of vesicles in axonal regions (the super pool) were reduced. This concurrent decrease suggests concerted control by FGF22 of presynaptic size. This hypothesis is supported by the finding that WT presynapses in the proximal part of area CA3 (CA3p) that do not receive FGF22 signaling in WT mice were smaller than presynapses in CA3d in WT but of comparable size in CA3d of FGF22KO mice. Docked SV density was decreased in CA1, CA3d, and CA3p in FGF22KO mice. Because CA1 and CA3p are not directly affected by the loss of FGF22, the smaller docked SV density may be an adaptation to activity changes in the CA3 network. Thus, docked SV density potentially is a long-term regulator for the synaptic release probability and/or the strength of short-term depression in vivo. PMID:26222899

  1. Dendritic spines as individual neuronal compartments for synaptic Ca2+ responses.

    Science.gov (United States)

    Müller, W; Connor, J A

    1991-11-01

    The possibility that postsynaptic spines on neuronal dendrites are discrete biochemical compartments for Ca(2+)-activated processes involved in synaptic plasticity is a widely proposed concept that has eluded experimental demonstration. Using microfluorometry on CA3 neurons in hippocampal slices, we show here that with weak presynaptic stimulation of associative/commissural fibres, Ca2+ accumulates in single postsynaptic spines but not in the parent dendrite. Stronger stimulation also promotes changes in dendrites. The NMDA-receptor antagonist AP-5 blocks changes in Ca2+ in spines. Sustained steep Ca2+ gradients between single spines and the parent dendrite, often lasting several minutes, develop with repeated stimulation. The observed compartmentalization allows for the specificity, cooperativity and associativity displayed by memory models such as long-term potentiation. PMID:1682815

  2. 14 CFR 23.729 - Landing gear extension and retraction system.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Landing gear extension and retraction... Design and Construction Landing Gear § 23.729 Landing gear extension and retraction system. (a) General. For airplanes with retractable landing gear, the following apply: (1) Each landing gear...

  3. 77 FR 31039 - Certain Electronic Devices Having a Retractable USB Connector; Institution of Investigation...

    Science.gov (United States)

    2012-05-24

    ... COMMISSION Certain Electronic Devices Having a Retractable USB Connector; Institution of Investigation... electronic devices having a retractable USB connector by reason of infringement of certain claims of U.S... retractable USB connector that infringe one or more of claims 1-4, 7, and 8 of the `210 patent and claims...

  4. 77 FR 24513 - Certain Electronic Devices Having a Retractable USB Connector; Notice of Receipt of Complaint...

    Science.gov (United States)

    2012-04-24

    ... COMMISSION Certain Electronic Devices Having a Retractable USB Connector; Notice of Receipt of Complaint... complaint entitled Certain Electronic Devices Having a Retractable USB Connector, DN 2892; the Commission is... certain electronic devices having a retractable USB connector. The complaint names as respondents...

  5. Random fractal dendrites

    OpenAIRE

    Croydon, David (David Alexander); Hambly, Ben M.; Dr. Ben Hambly

    2006-01-01

    Dendrites are tree-like topological spaces, and in this thesis, the physical characteristics of various random fractal versions of this type of set are investigated. This work will contribute to the development of analysis on fractals, an area which has grown considerably over the last twenty years. First, a collection of random self-similar dendrites is constructed, and their Hausdorff dimension is calculated. Previous results determining this quantity for random self-simi...

  6. Radioresistance of dendritic cells

    International Nuclear Information System (INIS)

    To evaluate radiation sensitivity of dendritic cells in comparison with lymphocytes. T lymphocytes captured from peripheral blood were irradiated by 0 Gy, 10 Gy, 30 Gy. Apoptosis was measured by flowcytometry for staining of annexin V 4 hours after irradiation. Immature and mature dendritic cells processed from blood hematopoietic stem cell were irradiated by 0 Gy, 10 Gy, 30 Gy, 100 Gy respectively and apoptosis was measured by flowcytometry with time differences as 4h, 24h and 48h after irradiation. Morphometric analysis by percent nucleus was measured in three cell groups, also. Lymphocytes showed radiation sensitivity by increasing apoptotic fraction according to radiation dose. However, both mature and immature dendritic cells showed consistent fraction of apoptosis in spite of increasing radiation dose. Percent nucleus ratio is significantly higher in lymphocytes than that of mature or immature dendritic cells. Stimulation of T-cell by dendritic cells was not changed after irradiation. Dendritic cells showed radioresistance which was associated with small size of nucleus in comparison with lymphocytes and this result would be used as a basal data of radio-labelling for the cellular trafficking studies in nuclear medicine fields

  7. Toward a self-wired active reconstruction of the hippocampal trisynaptic loop: DG-CA3

    Directory of Open Access Journals (Sweden)

    Gregory J. Brewer

    2013-10-01

    Full Text Available The mammalian hippocampus functions to encode and retrieve memories by transiently changing synaptic strengths, yet encoding in individual subregions for transmission between regions remains poorly understood. Toward the goal of better understanding the coding in the trisynaptic pathway from the dentate gyrus (DG to the CA3 and CA1, we report a novel microfabricated device that divides a micro-electrode array into two compartments of separate hippocampal network subregions connected by axons that grow through 3x10x400 μm tunnels. Gene expression by qPCR demonstrated selective enrichment of separate DG, CA3 and CA1 subregions. Reconnection of DG to CA3 altered burst dynamics associated with marked enrichment of GAD67 in DG and GFAP in CA3. Surprisingly, DG axon spike propagation was preferentially unidirectional to the CA3 region at 0.5 m/s with little reverse transmission. Therefore, select hippocampal subregions intrinsically self-wire in anatomically appropriate patterns and maintain their distinct subregion phenotype without external inputs

  8. Thermodynamic stability of Ca3TeO6 determined by a solid electrolyte EMF method

    International Nuclear Information System (INIS)

    Highlights: • Gibbs energy of formation of Ca3TeO6 experimentally determined for the first time. • Oxygen concentration galvanic cells based on YSZ solid electrolyte were employed. • In the Ca–Te–O system, Ca3TeO6 coexists with CaO and Te. - Abstract: The standard thermodynamic properties of Ca3TeO6 were determined electrochemically utilizing fast O2− ion conducting solid electrolyte yttria-stabilized zirconia. The ternary phase was synthesized from the pure oxides CaO and TeO2 in excess of CaO. The electromotive force measurements were performed on two similar electrochemical cells of the type Te + CaO + Ca3TeO6|YSZ|O2, within the temperature range from 850 to 949 K. The standard Gibbs energy of formation for the ternary compound Ca3TeO6 was determined for the first time, based on the experimental data obtained

  9. Gap junctions between CA3 pyramidal cells contribute to network synchronization in neonatal hippocampus.

    Science.gov (United States)

    Molchanova, Svetlana M; Huupponen, Johanna; Lauri, Sari E; Taira, Tomi

    2016-08-01

    Direct electrical coupling between neurons through gap junctions is prominent during development, when synaptic connectivity is scarce, providing the additional intercellular connectivity. However, functional studies of gap junctions are hampered by the unspecificity of pharmacological tools available. Here we have investigated gap-junctional coupling between CA3 pyramidal cells in neonatal hippocampus and its contribution to early network activity. Four different gap junction inhibitors, including the general blocker carbenoxolone, decreased the frequency of network activity bursts in CA3 area of hippocampus of P3-6 rats, suggesting the involvement of electrical connections in the generation of spontaneous network activity. In CA3 pyramidal cells, spikelets evoked by local stimulation of stratum oriens, were inhibited by carbenoxolone, but not by inhibitors of glutamatergic and GABAergic synaptic transmission, signifying the presence of electrical connectivity through axo-axonic gap junctions. Carbenoxolone also decreased the success rate of firing antidromic action potentials in response to stimulation, and changed the pattern of spontaneous action potential firing of CA3 pyramidal cells. Altogether, these data suggest that electrical coupling of CA3 pyramidal cells contribute to the generation of the early network events in neonatal hippocampus by modulating their firing pattern and synchronization. PMID:26926429

  10. System Ca3(VO4)2-Na3VO4-LaVO4

    International Nuclear Information System (INIS)

    Using the method of x-ray phase analysis, the phase equilibria in the system Ca3(VO4)2-Na3VO4-LaVO4 were studied. An extensive solid solution in calcium orthovanadate bounded by the compositions Ca3(VO4)2-Ca9La(VO4)7-Ca10Na(VO4)7-Ca8.5Na1.75La0.75(V)4)7 was found. The unit cell parameters of whitlockite vanadates increase with a rise in the sodium or lanthanum concentration. Ferroelectric phase transitions in Ca3-3xLa2x(VO4)2 vanadates were studied using thermal analysis, electrical conductivity measurements, and dielectric constant measurements

  11. A new form of Ca3P2 with a ring of Dirac nodes

    International Nuclear Information System (INIS)

    We report the synthesis and crystal structure of a new high-temperature form of Ca3P2. The crystal structure was determined through Rietveld refinements of synchrotron powder x-ray diffraction data. This form of Ca3P2 has a crystal structure of the hexagonal Mn5Si3 type, with a Ca ion deficiency compared to the ideal 5:3 stoichiometry. This yields a stable, charge-balanced compound of Ca2+ and P3−. We also report the observation of a secondary hydride phase, Ca5P3H, which again is a charge-balanced compound. The calculated band structure of Ca3P2 indicates that it is a three-dimensional Dirac semimetal with a highly unusual ring of Dirac nodes at the Fermi level. The Dirac states are protected against gap opening by a mirror plane in a manner analogous to what is seen for graphene

  12. Jumlah Sel Piramidal CA3 Hipokampus Tikus Putih Jantan pada Berbagai Model Stres Kerja Kronik

    Directory of Open Access Journals (Sweden)

    Fitranto Arjadi

    2014-12-01

    Full Text Available Prolonged and chronic exposure to stress leads to the loss of neurons at the CA3 (cornu ammonis hippocampus region and spatial memory deficits. The aim of this study was to study the number of CA3 pyramidal cells in albino rats that were exposed to chronic stress of works model consisting of paradoxical sleep deprivation (PSD, immobilization, and foot shock stresses. The method applied was the post-test only method with control group experimental design using completed randomized design (CRD on 24 3–4 month old male Wistar rats. The rats were divided into 4 groups: group I (control, group II (PSD stress, group III (immobilization stress, and group IV (footshock stress. The CA3 pyramidal cell hippocampus was stained with toluidine-blue. The number of CA3 pyramidal cell of hippocampus was counted using Image raster v2.1 software at 400x magnification in 10 duplicates for each sample. The study was conducted in six months (April–September 2012 at the Animal Laboratory, Faculty of Medical and Health Sciences, Jenderal Soedirman University. Analysis for the differences in the number of CA3 pyramidal cells was conducted using analysis of variance (ANOVA with Post-Hoc LSD. The results of the ANOVA showed a p value=0.037, meaning that there was significant difference in at least two groups of treatment. Further statistical test using Post-Hoc LSD showed a significant difference between the control group (12.9±2.47 and the chronic immobillization group (9,00±1,53 (p<0.05. In conclusion, the chronic immobillization stress group has the lowest average number of hippocampus CA3 pyramidal cells compared to other groups.

  13. TCDQ-TCT retraction and losses during asynchronous beam dump

    CERN Document Server

    Bracco, Chiara; Quaranta, Elena; CERN. Geneva. ATS Department

    2016-01-01

    The protection provided by the TCDQs in case of asynchronous beam dump depends strongly on their correct setup. They have to respect the strict hierarchy of the full collimation system and shield the tertiary collimators in the experimental regions. This MD aimed at performing asynchronous beam dump tests with different configurations, in order to assess the minimum allowed retraction between TCTs and TCDQs and, as a consequence, on the The protection provided by the TCDQs in case of asynchronous beam dump depends strongly on their correct setup. They have to respect the strict hierarchy of the full collimation system and shield the tertiary collimators in the experimental regions. This MD aimed at performing asynchronous beam dump tests with different configurations, in order to assess the minimum allowed retraction between TCTs and TCDQs and, as a consequence, on the β* reach.

  14. Pyrotechnic Actuator for Retracting Tubes Between MSL Subsystems

    Science.gov (United States)

    Gallon, John C.; Webster, Richard G.; Patterson, Keith D.; Orzewalla, Matthew A.; Roberts, Eric T.; Tuszynski, Andrew J.

    2010-01-01

    An apparatus, denoted the "retractuator" (a contraction of "retracting actuator"), was designed to help ensure clean separation between the cruise stage and the entry-vehicle subsystem of the Mars Science Laboratory (MSL) mission. The retractuator or an equivalent mechanism is needed because of tubes that (1) transport a heat-transfer fluid between the stages during flight and (2) are cut immediately prior to separation of the stages retractuator. The role of the retractuator is to retract the tubes, after they are cut and before separation of the subsystem, so that cut ends of the tubes do not damage thermal-protection coats on the entry vehicle and do not contribute to uncertainty of drag and consequent uncertainty in separation velocity.

  15. Thermoelectric Properties and Electronic Structure of Ca3Co2O6

    Institute of Scientific and Technical Information of China (English)

    AN Ji-ming; MIN Xin-min; CHEN Sheng-li; NAN Ce-wen

    2004-01-01

    The nanosized Ca3Co2O6 powder was synthesized via sol-gel process. The phase composition was characterized by means of X-ray diffraction. Polycrystalline samples of Ca3Co2O6 were prepared by a sintering procedure of nanosized power. The seebeck coefficient and electrical conductivity of the samples were measured from 450K up to 750K. The results show that the Seebeck coefficient increases with the increasing temperature. The electronic structures were calculated using the self-consistent full-potential linearized augmented plane-wave(LAPW) method within the density functional theory. The relationship between thermoelectric property and electronic structures was discussed.

  16. Adjustable sutures in eyelid surgery for ptosis and lid retraction.

    OpenAIRE

    Collin, J R; O'Donnell, B A

    1994-01-01

    New techniques are described and illustrated for ptosis and lid retraction surgery in which the sutures holding the upper eyelid position are adjustable postoperatively. In the anterior approach, the sutures pass from the levator muscle through the anterior surface of the tarsal plate at the position of the skin crease and are tied at the skin crease incision. In the posterior approach, the sutures pass from the levator muscle through the cut upper edge of the tarsal plate and are tied at the...

  17. Retraction With Face Saving: modelling conversational interaction through dynamic hypermedia

    OpenAIRE

    Baldry, Anthony; Piastra, Marco; Bolognesi, Roberto

    2011-01-01

    This paper describes RWFS (Retraction With Face Saving), a hypermedia application which models an interview between a lawyer and his client - a lorry driver - facing court charges of reckless driving. At one level RWFS takes the form of a sophisticated game in which different outcomes to the interview are possible according to the learner's degree of skill. At another level, RWFS is designed to encourage the language learner's awareness and understanding of the pragmatic features of conversat...

  18. Retractions of the gingival margins evaluated by holographic methods

    Science.gov (United States)

    Sinescu, Cosmin; Negrutiu, Meda Lavinia; Manole, Marius; de Sabata, Aldo; Rusu, Laura-Cristina; Stratul, Stefan; Dudea, Diana; Dughir, Ciprian; Duma, Virgil-Florin

    2015-05-01

    The periodontal disease is one of the most common pathological states of the teeth and gums system. The issue is that its evaluation is a subjective one, i.e. it is based on the skills of the dental medical doctor. As for any clinical condition, a quantitative evaluation and monitoring in time of the retraction of the gingival margins is desired. This phenomenon was evaluated in this study with a holographic method by using a He-Ne laser with a power of 13 mW. The holographic system we have utilized - adapted for dentistry applications - is described. Several patients were considered in a comparative study of their state of health - regarding their oral cavity. The impressions of the maxillary dental arch were taken from a patient during his/her first visit and after a period of six months. The hologram of the first model was superposed on the model cast after the second visit. The retractions of the gingival margins could be thus evaluated three-dimensionally in every point of interest. An evaluation of the retraction has thus been made. Conclusions can thus be drawn for the clinical evaluation of the health of the teeth and gums system of each patient.

  19. Optimizing Anterior En Masse Retraction with Miniscrew Anchorage

    Directory of Open Access Journals (Sweden)

    Pavankumar Janardan Vibhute

    2011-01-01

    Full Text Available In severely protrusive patients, skeletal anchorage from miniscrew is often used to avoid anchorage loss with preferred miniscrew location near centre of resistance (Cres of posterior teeth. Biomechanical requirement for directing retraction force towards Cres of posterior teeth demands the insertion of miniscrew in loose mucosa, where risk of infection and failure increases. In addition, undesirable biomechanical side effects on anterior and posterior segments may be possible in all three planes, when continuous arch sliding mechanics are installed with miniscrew anchorage. This paper describes technique of molar-stabilizing power arm (MSPA for simultaneous intrusion and retraction of anteriors with miniscrew placement at attached gingiva between 1st molar and 2nd premolar. Advantages of this technique include (i the need of miniscrews placement in loose mucosa apically near the Cres of the posterior teeth is eliminated, (ii the risk of infection and miniscrew failure is lowered since the miniscrew is placed in attached gingiva rather than the loose mucosa, and (iii by adjusting vertical length or replacing MSPA, alteration of the retraction force vector is possible in all three planes; thus, need of removal and repositioning of the miniscrew (e.g., in correction of occlusal cant can be eliminated.

  20. Ampullary Adenoma Treated by Endoscopic Double-Snare Retracting Papillectomy.

    Science.gov (United States)

    Soma, Hiromitsu; Miyata, Naoteru; Hozawa, Shigenari; Higuchi, Hajime; Yamagishi, Yoshiyuki; Nakamura, Yuji; Saeki, Keita; Kameyama, Kaori; Masugi, Yohei; Yahagi, Naohisa; Kanai, Takanori

    2015-09-23

    We report herein improved methods for the safe and successful completion of endoscopic papillectomy (EP). Between January 2008 and November 2011, 12 patients underwent double-snare retracting papillectomy for the treatment of lesions of the major duodenal papilla. The main outcomes were en bloc resection rates, pathological findings, and adverse events. All of the patients (mean age, 60.1 years; range, 38 to 80 years) were diagnosed with ampullary adenoma by endoscopic forceps biopsies prior to endoscopic snare papillectomy. En bloc resection by double-snare retracting papillectomy was successfully performed for all lesions (median size, 12.3 mm), comprising six tubular adenomas, one tubulovillous adenoma, three cases of epithelial atypia, one hamartomatous polyp, and one case of duodenitis with regenerative change. Significant hemorrhage and pancreatitis were observed in one case after EP. Adenoma recurrence occurred in three patients during follow-up (median, 28.5 months) at a mean interval of 2 months postoperatively (range, 1 to 3 months). No serious adverse events were observed. Double-snare retracting papillectomy is effective and feasible for treating lesions of the major duodenal papilla. Further treatment experience, including a single-arm phase II study, needs to be accumulated before conducting a randomized controlled study. PMID:26087781

  1. Optimizing anterior en masse retraction with miniscrew anchorage.

    Science.gov (United States)

    Vibhute, Pavankumar Janardan

    2011-01-01

    In severely protrusive patients, skeletal anchorage from miniscrew is often used to avoid anchorage loss with preferred miniscrew location near centre of resistance (Cres) of posterior teeth. Biomechanical requirement for directing retraction force towards Cres of posterior teeth demands the insertion of miniscrew in loose mucosa, where risk of infection and failure increases. In addition, undesirable biomechanical side effects on anterior and posterior segments may be possible in all three planes, when continuous arch sliding mechanics are installed with miniscrew anchorage. This paper describes technique of molar-stabilizing power arm (MSPA) for simultaneous intrusion and retraction of anteriors with miniscrew placement at attached gingiva between 1st molar and 2nd premolar. Advantages of this technique include (i) the need of miniscrews placement in loose mucosa apically near the Cres of the posterior teeth is eliminated, (ii) the risk of infection and miniscrew failure is lowered since the miniscrew is placed in attached gingiva rather than the loose mucosa, and (iii) by adjusting vertical length or replacing MSPA, alteration of the retraction force vector is possible in all three planes; thus, need of removal and repositioning of the miniscrew (e.g., in correction of occlusal cant) can be eliminated. PMID:22567438

  2. Type-IV Pilus Deformation Can Explain Retraction Behavior

    CERN Document Server

    Ghosh, Ranajay; Vaziri, Ashkan

    2014-01-01

    Polymeric filament like type IV Pilus (TFP) can transfer forces in excess of 100pN during their retraction before stalling, powering surface translocation(twitching). Single TFP level experiments have shown remarkable nonlinearity in the retraction behavior influenced by the external load as well as levels of PilT molecular motor protein. This includes reversal of motion near stall forces when the concentration of the PilT protein is lowered significantly. In order to explain this behavior, we analyze the coupling of TFP elasticity and interfacial behavior with PilT kinetics. We model retraction as reaction controlled and elongation as transport controlled process. The reaction rates vary with TFP deformation which is modeled as a compound elastic body consisting of multiple helical strands under axial load. Elongation is controlled by monomer transport which suffer entrapment due to excess PilT in the cell periplasm. Our analysis shows excellent agreement with a host of experimental observations and we prese...

  3. Dendritic Polymers for Theranostics

    Science.gov (United States)

    Ma, Yuan; Mou, Quanbing; Wang, Dali; Zhu, Xinyuan; Yan, Deyue

    2016-01-01

    Dendritic polymers are highly branched polymers with controllable structures, which possess a large population of terminal functional groups, low solution or melt viscosity, and good solubility. Their size, degree of branching and functionality can be adjusted and controlled through the synthetic procedures. These tunable structures correspond to application-related properties, such as biodegradability, biocompatibility, stimuli-responsiveness and self-assembly ability, which are the key points for theranostic applications, including chemotherapeutic theranostics, biotherapeutic theranostics, phototherapeutic theranostics, radiotherapeutic theranostics and combined therapeutic theranostics. Up to now, significant progress has been made for the dendritic polymers in solving some of the fundamental and technical questions toward their theranostic applications. In this review, we briefly summarize how to control the structures of dendritic polymers, the theranostics-related properties derived from their structures and their theranostics-related applications.

  4. Oxygen transport kinetics of the misfit layered oxide Ca3Co4O9+d

    NARCIS (Netherlands)

    Thoréton, V.; Hu, Y.; Pirovano, C.; Capoen, E.; Nuns, N.; Mamede, A.S.; Dezanneau, G.; Yoo, C.-Y.; Bouwmeester, H.J.M.; Vannier, R.N.

    2014-01-01

    The oxygen transport kinetics of the misfit-layered cobaltite, Ca3Co4O9+d, known for its thermoelectric properties, was investigated by combined application of 18O/16O isotope exchange and electrical conductivity relaxation techniques. Although oxygen diffusion is found to be two orders of magnitude

  5. Preparation and Luminescence Characteristics of Ca3Y2(BO3)4:Eu3+ Phosphor

    Institute of Scientific and Technical Information of China (English)

    LI Pan-Lai; YANG Zhi-Ping; WANG Zhi-Jun; Guo Qing-Lin

    2007-01-01

    Ca3Y2(BO3)4:Eu3+ phosphor is synthesized by high temperature solid-state reaction method, and the luminescence characteristics are investigated. The emission spectrum exhibits two strong red emissions at 613 and 621 nm corresponding to the electric dipole 5 Do-7F2 transition of Eu3+ under 365 nm excitation, the reason is that Eu3+ substituting for y3+ occupies the non-centrosymmetric position in the crystal structure of Ca3Y2 (BO3 )4. The excitation spectrum for 613 nm indicates that the phosphor can be effectively excited by ultraviolet (UV) (254 nm,365nm and 400nm) and blue (470nm) light. The effect of Eu3+ concentration on the emission intensity of Ca3Y2 (BO3 )4:Eu3+ phosphor is measured, the result shows that the emission intensities increase with increasing Eu3+ concentration, then decrease. The CIE colour coordinates of Ca3Y2(BO3)4:Eu3+ phosphor is (0.639, 0.357) at 15mol% Eu3+.

  6. Electronic Structure and Thermoelectric Properties of Ca3 Co4O9

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The relation among electronic structure, chemical bond and thermoelectric property of Ca3 Co4 O9 was studied using density function and discrete variation method (DFT-DVM).The gap between the highest valence band (HVB) and the lowest conduction band (LCB) shows a semiconducting property.Ca3 Co4 O9 colsists of CoO2 and Ca2 CoO3 two layers.The HVB and LCB near Fermi level are only mainly from O(2) 2p and Co(2) 3d in Ca2 CoO3 layer. Therefore, the semiconducting or thermoelectric property of Ca3 Co4 O9 should be mainly from Ca2 CoO3 layer, but it seems to have no direct relation to the CoO2 layer,which is consistent with that binary oxides hardly have a thermoelectric property, but trinary oxide compounds have quite a good thermoelectric property.The covalent and ionic bonds of Ca2 CoO3 layer are both weaker than those of CoO2 layer.Ca plays the role of connections between CoO2 and Ca2 CoO3 layers in Ca3 Co4 O9, decrease the ionic and covalent bond strength, and improve the thermoelectric property.

  7. Cooperative retraction of bundled type IV pili enables nanonewton force generation.

    Directory of Open Access Journals (Sweden)

    Nicolas Biais

    2008-04-01

    Full Text Available The causative agent of gonorrhea, Neisseria gonorrhoeae, bears retractable filamentous appendages called type IV pili (Tfp. Tfp are used by many pathogenic and nonpathogenic bacteria to carry out a number of vital functions, including DNA uptake, twitching motility (crawling over surfaces, and attachment to host cells. In N. gonorrhoeae, Tfp binding to epithelial cells and the mechanical forces associated with this binding stimulate signaling cascades and gene expression that enhance infection. Retraction of a single Tfp filament generates forces of 50-100 piconewtons, but nothing is known, thus far, on the retraction force ability of multiple Tfp filaments, even though each bacterium expresses multiple Tfp and multiple bacteria interact during infection. We designed a micropillar assay system to measure Tfp retraction forces. This system consists of an array of force sensors made of elastic pillars that allow quantification of retraction forces from adherent N. gonorrhoeae bacteria. Electron microscopy and fluorescence microscopy were used in combination with this novel assay to assess the structures of Tfp. We show that Tfp can form bundles, which contain up to 8-10 Tfp filaments, that act as coordinated retractable units with forces up to 10 times greater than single filament retraction forces. Furthermore, single filament retraction forces are transient, whereas bundled filaments produce retraction forces that can be sustained. Alterations of noncovalent protein-protein interactions between Tfp can inhibit both bundle formation and high-amplitude retraction forces. Retraction forces build over time through the recruitment and bundling of multiple Tfp that pull cooperatively to generate forces in the nanonewton range. We propose that Tfp retraction can be synchronized through bundling, that Tfp bundle retraction can generate forces in the nanonewton range in vivo, and that such high forces could affect infection.

  8. Modification of dendritic development.

    Science.gov (United States)

    Feria-Velasco, Alfredo; del Angel, Alma Rosa; Gonzalez-Burgos, Ignacio

    2002-01-01

    Since 1890 Ramón y Cajal strongly defended the theory that dendrites and their processes and spines had a function of not just nutrient transport to the cell body, but they had an important conductive role in neural impulse transmission. He extensively discussed and supported this theory in the Volume 1 of his extraordinary book Textura del Sistema Nervioso del Hombre y de los Vertebrados. Also, Don Santiago significantly contributed to a detailed description of the various neural components of the hippocampus and cerebral cortex during development. Extensive investigation has been done in the last Century related to the functional role of these complex brain regions, and their association with learning, memory and some limbic functions. Likewise, the organization and expression of neuropsychological qualities such as memory, exploratory behavior and spatial orientation, among others, depend on the integrity and adequate functional activity of the cerebral cortex and hippocampus. It is known that brain serotonin synthesis and release depend directly and proportionally on the availability of its precursor, tryptophan (TRY). By using a chronic TRY restriction model in rats, we studied their place learning ability in correlation with the dendritic spine density of pyramidal neurons in field CA1 of the hippocampus during postnatal development. We have also reported alterations in the maturation pattern of the ability for spontaneous alternation and task performance evaluating short-term memory, as well as adverse effects on the density of dendritic spines of hippocampal CA1 field pyramidal neurons and on the dendritic arborization and the number of dendritic spines of pyramidal neurons from the third layer of the prefrontal cortex using the same model of TRY restriction. The findings obtained in these studies employing a modified Golgi method, can be interpreted as a trans-synaptic plastic response due to understimulation of serotoninergic receptors located in the

  9. Insulating state and the importance of the spin-orbit coupling in Ca$_3$CoRhO$_6$

    OpenAIRE

    Wu, Hua; Z. Hu; Khomskii, D. I.; Tjeng, L. H.

    2007-01-01

    We have carried out a comparative theoretical study of the electronic structure of the novel one-dimensional Ca$_3$CoRhO$_6$ and Ca$_3$FeRhO$_6$ systems. The insulating antiferromagnetic state for the Ca$_3$FeRhO$_6$ can be well explained by band structure calculations with the closed shell high-spin $d^5$ (Fe$^{3+}$) and low-spin $t_{2g}^{6}$ (Rh$^{3+}$) configurations. We found for the Ca$_3$CoRhO$_6$ that the Co has a strong tendency to be $d^7$ (Co$^{2+}$) rather than $d^6$ (Co$^{3+}$), a...

  10. Electronic and Optical Properties of Ca3MN (M = Ge, Sn, Pb, P, As, Sb and Bi) Antiperovskite Compounds

    Science.gov (United States)

    Iqbal, Samad; Murtaza, G.; Khenata, R.; Mahmood, Asif; Yar, Abdullah; Muzammil, M.; Khan, Matiullah

    2016-08-01

    The electronic and optical properties of cubic antiperovskites Ca3MN (M = Ge, Sn, Pb, P, As, Sb and Bi) were investigated by applying the full potential linearized augmented plane wave plus local orbitals (FP-LAPW + lo) scheme based on density functional theory. Different exchange correlation potentials were adopted for the calculations. The results of band structure and density of states show that, by changing the central anion of Ca3MN, the nature of the materials change from metallic (Ca3GeN, Ca3SnN, Ca3PbN) to semiconducting with small band gaps (Ca3SbN and Ca3BiN) to insulating (Ca3PN and Ca3AsN). The optical properties such as dielectric function, absorption coefficient, optical conductivity, reflectivity and refractive indices have also been calculated. The results reveal that all the studied compounds are optically active in the visible and ultraviolet energy regions, and therefore can be effectively utilized for optoelectronic devices.

  11. In Vivo Investigation of the Effectiveness of a Hyper-viscoelastic Model in Simulating Brain Retraction.

    Science.gov (United States)

    Li, Ping; Wang, Weiwei; Zhang, Chenxi; An, Yong; Song, Zhijian

    2016-01-01

    Intraoperative brain retraction leads to a misalignment between the intraoperative positions of the brain structures and their previous positions, as determined from preoperative images. In vitro swine brain sample uniaxial tests showed that the mechanical response of brain tissue to compression and extension could be described by the hyper-viscoelasticity theory. The brain retraction caused by the mechanical process is a combination of brain tissue compression and extension. In this paper, we first constructed a hyper-viscoelastic framework based on the extended finite element method (XFEM) to simulate intraoperative brain retraction. To explore its effectiveness, we then applied this framework to an in vivo brain retraction simulation. The simulation strictly followed the clinical scenario, in which seven swine were subjected to brain retraction. Our experimental results showed that the hyper-viscoelastic XFEM framework is capable of simulating intraoperative brain retraction and improving the navigation accuracy of an image-guided neurosurgery system (IGNS). PMID:27387301

  12. In Vivo Investigation of the Effectiveness of a Hyper-viscoelastic Model in Simulating Brain Retraction

    Science.gov (United States)

    Li, Ping; Wang, Weiwei; Zhang, Chenxi; An, Yong; Song, Zhijian

    2016-07-01

    Intraoperative brain retraction leads to a misalignment between the intraoperative positions of the brain structures and their previous positions, as determined from preoperative images. In vitro swine brain sample uniaxial tests showed that the mechanical response of brain tissue to compression and extension could be described by the hyper-viscoelasticity theory. The brain retraction caused by the mechanical process is a combination of brain tissue compression and extension. In this paper, we first constructed a hyper-viscoelastic framework based on the extended finite element method (XFEM) to simulate intraoperative brain retraction. To explore its effectiveness, we then applied this framework to an in vivo brain retraction simulation. The simulation strictly followed the clinical scenario, in which seven swine were subjected to brain retraction. Our experimental results showed that the hyper-viscoelastic XFEM framework is capable of simulating intraoperative brain retraction and improving the navigation accuracy of an image-guided neurosurgery system (IGNS).

  13. Surgical management of retraction pockets of the pars tensa with cartilage and perichondrial grafts.

    Science.gov (United States)

    Spielmann, P; Mills, R

    2006-09-01

    Stable, self-cleansing retraction pockets of the pars tensa are common incidental findings and require no treatment. In other cases, recurrent discharge occurs and there may also be associated conductive hearing loss. In a minority of cases, cholesteatoma may develop. This paper presents the results of surgery using a graft composed of cartilage and perichondrium for retraction pockets involving the posterior half of the tympanic membrane, as well as early results using a larger graft designed to manage retraction of the entire tympanic membrane. Data on 51 patients with posterior retraction pockets are presented. Forty-two (82 per cent) patients had no aural discharge one year following surgery and the tympanic membrane was not retracted in 43 (84 per cent). The larger 'Mercedes-Benz' graft was used in four patients and the results obtained suggested that it may prove a successful technique for extensive retraction pockets. PMID:16740207

  14. Biologic targeting in the treatment of inflammatory bowel diseases [Retraction

    Directory of Open Access Journals (Sweden)

    Bosani M

    2014-01-01

    Full Text Available Bosani M, Ardizzone S, Porro GB. Biologics: Targets and Therapy. 2009;3:77–97.This paper has been retracted after we were made aware that it contains a large amount of reused, and uncited material that was not placed within quotation marks.The following statement has been supplied by Dr Sandro Ardizzone:The review entitled "Biologic targeting in the treatment of inflammatory bowel disease" has been commissioned by this journal and published in 2009 (Matteo Bosani, Sandro Ardizzone, Gabriele Bianchi Porro. Biologics: Targets & Therapy 2009;3:77–97. The paper was written by our young coworker (Dr M Bosani. He has consulted many papers, including our previous reviews published years before. The not perfect knowledge of English language has greatly influenced the writing of the paper itself. So he saved in word file several parts of our previous papers (Ardizzone S, Bianchi Porro G. Inflammatory bowel disease: new insights into pathogenesis and treatment. J Intern Med 2002;252:475–496 – Ardizzone S, Bianchi Porro G. Biologic therapy for inflammatory bowel disease. Drugs 2005:2253–2286, and then transferred to the final paper. He was unaware as we are, of the fact that he could not reuse previously published material in other journals. The reuse of this material was made in good faith.Taking our responsibility for what happened, we intend to apologize for this inconvenience to the Editor (Dr Doris Benbrook and Publisher (Dr Tim Hill. Moreover, for the reasons mentioned above, I consider appropriate to retract the paper itself.This retraction relates to this paper.

  15. CASE REPORT How to Repair the Lower Eyelid Retraction, Resulting From the Primary Surgery for Epiblepharon?

    OpenAIRE

    Asamura, Shinichi; Kakizaki, Hirohiko; Matsushima, Seika; Morotomi, Tadaaki; Isogai, Noritaka

    2013-01-01

    Objective: Among the surgical procedures used to correct the positions of the eyelids or improve their cosmetic appearance, procedures for treating eyelid retraction are some of the most challenging. Lower eyelid retraction can occur iatrogenically after various surgical procedures. We performed a successful corrective procedure for lower eyelid retraction, which had occurred at some point in the 2 decades after primary surgery for epiblepharon. Method: A 23-year-old woman underwent primary s...

  16. Space-time Geodesics of the 5D Schwarzschild field and its deformation retract

    CERN Document Server

    Ahmed, Nasr

    2014-01-01

    In this article we introduce some types of the deformtion retracts of the $5D$ Schwarzchild space making use of Lagrangian equations. The retraction of this space into itself and into geodesics has been presented. The relation between folding and deformation retract of this space has been achieved. A relation for energy conservation similar to the one obtained in four dimensions has been obtained for the five dimensional case.

  17. Simultaneous Occurrence of Duane Retraction Syndrome with Marfan Syndrome

    Directory of Open Access Journals (Sweden)

    Mihir Kothari

    2011-01-01

    Full Text Available Marfan syndrome (MFS is an autosomal dominant disorder of connective tissue, while Duane retraction syndrome (DRS is a congenital cranial dysinnervation disorder (CCDD which can be transmitted as autosomal dominant disorder in 5–10% of patients. In this paper, we present an 8-year-old girl who presented with left eye DRS and bilateral subluxation of the lens associated with MFS in absence of familial involvement. To our knowledge this is the first case report of DRS with MFS. The occurrence of these syndromes together is very rare and appears to be coincidental.

  18. Correction of Alar Retraction Based on Frontal Classification.

    Science.gov (United States)

    Kim, Jae Hoon; Song, Jin Woo; Park, Sung Wan; Bartlett, Erica; Nguyen, Anh H

    2015-11-01

    Among the various types of alar deformations in Asians, alar retraction not only has the highest occurrence rate, but is also very complicated to treat because the ala is supported only by cartilage and its soft tissue envelope cannot be easily stretched. As patients' knowledge of aesthetic procedures is becoming more extensive due to increased information dissemination through various media, doctors must give more accurate, logical explanations of the procedures to be performed and their anticipated results, with an emphasis on relevant anatomical features, accurate diagnoses, detailed classifications, and various appropriate methods of surgery. PMID:26648808

  19. Ca3P2 and other topological semimetals with line nodes and drumhead surface states

    Science.gov (United States)

    Chan, Y.-H.; Chiu, Ching-Kai; Chou, M. Y.; Schnyder, Andreas P.

    2016-05-01

    As opposed to ordinary metals, whose Fermi surfaces are two dimensional, topological (semi)metals can exhibit protected one-dimensional Fermi lines or zero-dimensional Fermi points, which arise due to an intricate interplay between symmetry and topology of the electronic wave functions. Here, we study how reflection symmetry, time-reversal symmetry, SU(2) spin-rotation symmetry, and inversion symmetry lead to the topological protection of line nodes in three-dimensional semimetals. We obtain the crystalline invariants that guarantee the stability of the line nodes in the bulk and show that a quantized Berry phase leads to the appearance of protected surfaces states, which take the shape of a drumhead. By deriving a relation between the crystalline invariants and the Berry phase, we establish a direct connection between the stability of the line nodes and the drumhead surface states. Furthermore, we show that the dispersion minimum of the drumhead state leads to a Van Hove singularity in the surface density of states, which can serve as an experimental fingerprint of the topological surface state. As a representative example of a topological semimetal, we consider Ca3P2 , which has a line of Dirac nodes near the Fermi energy. The topological properties of Ca3P2 are discussed in terms of a low-energy effective theory and a tight-binding model, derived from ab initio DFT calculations. Our microscopic model for Ca3P2 shows that the drumhead surface states have a rather weak dispersion, which implies that correlation effects are enhanced at the surface of Ca3P2 .

  20. Terminal Field and Firing Selectivity of Cholecystokinin-Expressing Interneurons in the Hippocampal CA3 Area

    OpenAIRE

    Lasztóczi, Bálint; Tukker, John J; Somogyi, Peter; Klausberger, Thomas

    2011-01-01

    Hippocampal oscillations reflect coordinated neuronal activity on many timescales. Distinct types of GABAergic interneuron participate in the coordination of pyramidal cells over different oscillatory cycle phases. In the CA3 area, which generates sharp waves and gamma oscillations, the contribution of identified GABAergic neurons remains to be defined. We have examined the firing of a family of cholecystokinin-expressing interneurons during network oscillations in urethane-anesthetized rats ...

  1. Hydrothermal synthesis of Ca3Bi8O15 rods and their visible light photocatalytic properties

    International Nuclear Information System (INIS)

    Graphical abstract: The novel Ca3Bi8O15 rods can utilize the sunlight efficiently with the small band-gap. Using methyl orange (MO) as a model organic pollutant, the photocatalysts exhibited good photocatalytic activity, with the photodegradation conversion ratio of MO being up to 90% after 2 h of visible light (420 nm < λ < 800 nm) irradiation. - Highlights: • Ca3Bi8O15 rods were synthesized by a hydrothermal method. • They can utilize the sunlight efficiently with the small band-gap. • They showed good photocatalytic activities in the degradation of MO, RhB and 4-CP. • The conversion ratio of MO was up to 90% after 2 h of visible light irradiation. - Abstract: High efficient visible light Ca3Bi8O15 photocatalysts were synthesized by a hydrothermal method. Characterized by X-ray diffractometer, transmission electron microscopy, and the UV–vis diffuse reflectance spectroscopy, the results showed that the novel Ca3Bi8O15 rods can utilize the sunlight efficiently with the small band-gap. Using methyl orange (MO) as a model organic pollutant, the photocatalysts exhibited good photocatalytic activity, with the photodegradation conversion ratio of MO being up to 90% after 2 h of visible light (420 nm < λ < 800 nm) irradiation. Furthermore, they also showed good photocatalytic activities in the degradation of rhodamine B and p-chlorophenol. Through the investigation of the degraded mechanism, the main active species played important roles in the degradation process were holes, O2·− and ·OH

  2. Optical conductivity of layered calcium cobaltate Ca3Co4O9.

    Science.gov (United States)

    Tanabe, Kenji; Okazaki, Ryuji; Taniguchi, Hiroki; Terasaki, Ichiro

    2016-03-01

    We report the optical properties of layered calcium cobaltate, Ca3Co4O9, which is regarded as a promising candidate for use as a thermoelectric material. The optical conductivity shows three broad peaks related to the inter-band transition below 4 eV, which are quite similar to those in the spectra of Na x CoO2. This similarity implies that the CoO2 layer, which is an essential unit for both Ca3Co4O9 and Na x CoO2, is dominant in the energy band structure below 4 eV. In addition, we estimate the effective carrier number per Co site and find similarity between the CoO2 layers of Ca3Co4O9 and Na0.75CoO2, which is consistent with the similarity in their Seebeck coefficients. To discuss the contribution of the rocksalt-type Ca2CoO3 layer in Ca3Co4O9, we propose the concept of optical sheet conductivity in the layered materials and estimate its value in the Ca2CoO3 layer. A comparison with the spin-polarized band calculation of the LDA  +  Hubbard U formalism with U  =  5 eV suggests that the Ca2CoO3 layer has the inter-band transition of 2.6 eV in the spin-down band structure. Evaluation of the valences of Co 3d orbitals indicates the existence of charge transfer from the Ca2CoO3 layer to the CoO2 layer and mixing of Co(3+) and Co(4+) in the CoO2 layer, which may be the origin of the large thermoelectric effect. PMID:26823444

  3. Crystal structure of Ca 3(VO 4) 2 synthesized at 11 GPa and 1373 K

    Science.gov (United States)

    Grzechnik, Andrzej

    2002-04-01

    A new polymorph of calcium orthovanadate Ca 3(VO 4) 2 has been synthesized at 11 GPa and 1373 K and recovered to ambient conditions. It crystallizes in a monoclinic cell (space group C2/m, Z=2) with a=9.6715(2), b=5.43276(7), c=7.0713(1) Å, β=116.949(1)°. The crystal structure has been solved ab initio from X-ray powder diffraction data using direct methods. The oxygen atoms form a hexagonal close packing. The VO 3-4 tetrahedra are radially and angularly distorted. The two crystallographically independent Ca atoms are in deformed octahedral and ten-fold coordinations. Unlike in the palmierite-derived parent Ba 3(VO 4) 2 (R 3¯m, Z=1) and Ca 3(VO 4) 2 (R3c, Z=7), this network is three-dimensional. The new monoclinic structure of calcium orthovanadate is discussed in relation to those of related orthophosphates and orthovanadates. It is suggested that the pressure-induced amorphization of Ca 3(VO 4) 2 (R3c, Z=7) at 10 GPa and room temperature could be due to kinetically inhibited changes in the dimensionality of the crystal structure.

  4. Magnetic and dendritic catalysts.

    Science.gov (United States)

    Wang, Dong; Deraedt, Christophe; Ruiz, Jaime; Astruc, Didier

    2015-07-21

    The recovery and reuse of catalysts is a major challenge in the development of sustainable chemical processes. Two methods at the frontier between homogeneous and heterogeneous catalysis have recently emerged for addressing this problem: loading the catalyst onto a dendrimer or onto a magnetic nanoparticle. In this Account, we describe representative examples of these two methods, primarily from our research group, and compare them. We then describe new chemistry that combines the benefits of these two methods of catalysis. Classic dendritic catalysis has involved either attaching the catalyst covalently at the branch termini or within the dendrimer core. We have used chelating pyridyltriazole ligands to insolubilize catalysts at the termini of dendrimers, providing an efficient, recyclable heterogeneous catalysts. With the addition of dendritic unimolecular micelles olefin metathesis reactions catalyzed by commercial Grubbs-type ruthenium-benzylidene complexes in water required unusually low amounts of catalyst. When such dendritic micelles include intradendritic ligands, both the micellar effect and ligand acceleration promote faster catalysis in water. With these types of catalysts, we could carry out azide alkyne cycloaddition ("click") chemistry with only ppm amounts of CuSO4·5H2O and sodium ascorbate under ambient conditions. Alternatively we can attach catalysts to the surface of superparamagnetic iron oxide nanoparticles (SPIONs), essentially magnetite (Fe3O4) or maghemite (γ-Fe2O3), offering the opportunity to recover the catalysts using magnets. Taking advantage of the merits of both of these strategies, we and others have developed a new generation of recyclable catalysts: dendritic magnetically recoverable catalysts. In particular, some of our catalysts with a γ-Fe2O3@SiO2 core and 1,2,3-triazole tethers and loaded with Pd nanoparticles generate strong positive dendritic effects with respect to ligand loading, catalyst loading, catalytic activity and

  5. Retraction Assembly for Space Shuttle Extended Nose Landing Gear

    Science.gov (United States)

    Files, Bradley S.; Nicholson, Leonard S. (Technical Monitor)

    2000-01-01

    As part of a project to encourage the use of shape memory alloy actuators for space actuators, this mechanism uses a nitinol ribbon to provide the necessary motion to help retract the proposed extended nose landing gear (ENLG) for the space shuttle. Initial proof-of-concept design of the ENLG did not include the ability to retract the gear automatically. One proposed actuator for this purpose was designed at Johnson Space Center and uses resistive heating to rotate the ribbon around a cylinder. This rotation then allows the assembly to pull down a wedge that is used to hold the landing gear strut in place, thus returning the landing gear to its previous height before extension. The presentation will follow the design of this assembly from working with the nitinol ribbon to providing mechanical connections and allowing minimal friction for motion of three wraps around a cylinder. Also to be presented is preliminary work on design of a shape memory alloy gripper, a design project to demonstrate uses of NiTi.

  6. Optical-luminescence properties of Ce3+ ions in Ca3 Ga2 Ge4O14 single crystals

    International Nuclear Information System (INIS)

    The optical-luminescence spectroscopic properties of Ca3 Ga2 Ge4 O14 single crystals doped with Ce3+ ions are investigated. It is shown that activator ions in Ca3 Ga2 Ge4 O14 form Ce3+ centers in Thomson cubes (3 e positions)

  7. Dendritic Cells and Liver Fibrosis

    OpenAIRE

    Rahman, Adeeb H.; Aloman, Costica

    2013-01-01

    Dendritic cells are a relative rare population of specialized antigen presenting cells that are distributed through most lymphoid and non-lymphoid tissues and play a critical role in linking the innate and adaptive arms of the immune system. The liver contains a heterogeneous population of dendritic cells that may contribute to liver inflammation and fibrosis through a number of mechanisms. This review summarizes current knowledge on the development and characterization of liver dendritic cel...

  8. Distinctive PSA-NCAM and NCAM Hallmarks in Glutamate-Induced Dendritic Atrophy and Synaptic Disassembly

    Science.gov (United States)

    Podestá, María Fernanda; Yam, Patricia; Codagnone, Martín Gabriel; Uccelli, Nonthué Alejandra; Colman, David; Reinés, Analía

    2014-01-01

    Dendritic and synapse remodeling are forms of structural plasticity that play a critical role in normal hippocampal function. Neural cell adhesion molecule (NCAM) and its polysialylated form (PSA-NCAM) participate in neurite outgrowth and synapse formation and plasticity. However, it remains unclear whether they contribute to dendritic retraction and synaptic disassembly. Cultured hippocampal neurons exposed to glutamate (5 µM) showed a reduced MAP-2 (+) area in the absence of neuronal death 24 h after the insult. Concomitantly, synapse loss, revealed by decreased synaptophysin and post-synaptic density-95 cluster number and area, together with changes in NCAM and PSA-NCAM levels were found. Dendritic atrophy and PSA-NCAM reduction proved NMDA-receptor dependent. Live-imaging experiments evidenced dendritic atrophy 4 h after the insult; this effect was preceded by smaller NCAM clusters (1 h) and decreased surface and total PSA-NCAM levels (3 h). Simultaneously, total NCAM cluster number and area remained unchanged. The subsequent synapse disassembly (6 h) was accompanied by reductions in total NCAM cluster number and area. A PSA mimetic peptide prevented both the dendritic atrophy and the subsequent synaptic changes (6 h) but had no effect on the earliest synaptic remodeling (3 h). Thus, NCAM-synaptic reorganization and PSA-NCAM level decrease precede glutamate-induced dendritic atrophy, whereas the NCAM level reduction is a delayed event related to synapse loss. Consequently, distinctive stages in PSA-NCAM/NCAM balance seem to accompany glutamate-induced dendritic atrophy and synapse loss. PMID:25279838

  9. 76 FR 472 - Harmonization of Airworthiness Standards for Transport Category Airplanes-Landing Gear Retracting...

    Science.gov (United States)

    2011-01-05

    ... Airworthiness Standards for Transport Category Airplanes--Landing Gear Retracting Mechanisms and Pilot... transport category airplanes on landing gear retracting mechanisms and the pilot compartment view. This... in a stalling maneuver, and would add an additional requirement to keep the landing gear and doors...

  10. 77 FR 1614 - Harmonization of Airworthiness Standards for Transport Category Airplanes-Landing Gear Retracting...

    Science.gov (United States)

    2012-01-11

    ... Register on January 5, 2011 (76 FR 472). The NPRM proposed to amend the standards for landing gear... Transport Category Airplanes--Landing Gear Retracting Mechanisms and Pilot Compartment View AGENCY: Federal... the airworthiness standards for transport category airplanes on landing gear retracting mechanisms...

  11. Magnetic Retraction of Bowel by Intraluminal Injectable Cyanoacrylate-Based Magnetic Glue

    Directory of Open Access Journals (Sweden)

    Zhigang Wang

    2013-01-01

    Full Text Available Magnetic retraction offers advantages over physical retraction by graspers because of reduced tissue trauma. The objectives of this study are to investigate a novel method of magnetisation of bowel segments by intraluminal injection of magnetic glue and to demonstrate the feasibility of magnetic retraction of bowel with sufficient force during minimal access surgery. Following an initial materials characterisation study, selected microparticles of stainless steel (SS410-μPs were mixed with chosen cyanoacrylate glue (Loctite 4014. During intraluminal injection of the magnetic glue using ex vivo porcine colonic segments, a magnetic probe placed at the injected site ensured that the SS410-μPs aggregated during glue polymerisation to form an intraluminal mucosally adherent coagulum. The magnetised colonic segments were retracted by magnetic probes (5 and 10 mm placed external to the bowel wall. A tensiometer was used to record the retraction force. With an injected volume of 2 mL in a particle concentration of 1 g/mL, this technique produced maximal magnetic retraction forces of 2.24 ± 0.23 N and 5.11 ± 0.34 N (, with use of 5 and 10 mm probes, respectively. The results indicate that the formation of an intraluminal coagulum based on SS410-μPs and Loctite 4014 produces sufficient magnetic retraction for bowel retraction.

  12. Acquisition of operant behavior in rats with delayed reinforcement: A retractable-lever procedure.

    Science.gov (United States)

    McNamara, Andrew A; Johnson, Lyndsey E; Tate, Christopher; Chiang, Thomas; Byrne, Tom

    2015-02-01

    Experimentally naïve rats acquired lever pressing with delayed reinforcement when the immediate programmed consequence for lever pressing was the simultaneous retraction of two identical levers. Presses on one lever also produced access to sweetened condensed milk after a delay of 10s following retraction. Presses on the second lever resulted in retraction only. Lever retraction prevented the possibility of adventitious reinforcement of contacting the operanda during the reinforcement delays. Several measures indicated that the delayed reinforcers strengthened behavior. The majority of responses for all rats were on the lever that initiated reinforcer delivery. Responding for seven out of eight rats decreased during a subsequent extinction phase in which retraction was the only consequence arranged for lever pressing. Responding recovered rapidly when food reinforcement was available again. Furthermore, when contingencies on the two levers were switched, rats allocated their behavior accordingly, showing control by the delayed reinforcers. PMID:25464338

  13. Assessment of brain retraction injury from tumor operation with 99Tcm-ECD brain SPECT imaging

    International Nuclear Information System (INIS)

    Objective: To evaluate the rCBF of brain retraction injury by 99Tcm-ECD SPECT imaging. Methods: The 99Tcm-ECD SPECT brain imaging was performed in 21 patients with brain tumor before and after operation. To compare the rCBF of peripheral tumor region with that of retraction injury region by semi-quantitative analysis. The rCBF levels of the central and peripheral areas of brain retraction injury were also studied. Results: Both the peripheral tumor region before operation and retraction region after operation were ischemic, but the difference between them was significant (P99Tcm-ECD SPECT brain imaging is a useful technique in detecting retraction injury come from brain tumor operation

  14. Energy transfer and luminescence dynamics in Ca3Gd2(BO3)4:Eu3+

    International Nuclear Information System (INIS)

    Eu3+-doped and -undoped Ca3Gd2(BO3)4 phosphors were synthesized by the high temperature solid-state reaction. The excitation and emission spectra and the decays of the Gd3+ and Eu3+ luminescence in Ca3Gd2(BO3)4:Eu3+ under excitation into the self-trapped excitation (STE) state are investigated in the wavelength region from vacuum ultraviolet to visible. The efficient energy transfer occurs from the host STE state to the emitting state of Eu3+5D0 via two intermediate states: the Gd3+6P7/2 state or the O–Eu charge transfer state. The analyses of decay curves of the Eu3+5D0 emission at 615 nm and the Gd3+6P7/2 emission at 314 nm show much faster energy transfer from Gd3+ to Eu3+ than the energy diffusion among the Gd3+ ions. -- Highlights: • Luminescence dynamics are investigated in Ca3Gd2(BO3)4:Eu3+. • The excited STE state relaxes to the Eu3+5D0 state through the Gd3+6P7/2 state or the O–Eu charge transfer state. • Much faster energy transfer occurs from Gd to Eu than the energy diffusion among the Gd3+ ions. • The feeding of the 5D0 population occurs dominantly from the O–Eu charge transfer state at higher Eu3+ concentration

  15. A General Version of the Retract Method for Discrete Equations

    Institute of Scientific and Technical Information of China (English)

    Josef DIBL(I)K; Irena R(U)(Z)I(C)KOV(A); Miroslava R(U)(Z)I(C)KOV(A)

    2007-01-01

    We study a problem concerning the compulsory behavior of the solutions of systems of iscrete equations u(k + 1) = F(k, u(k)), k ∈ N(a) = {a, a + 1, a + 2, ...}, a ∈ N, N = {0, 1, ...} and : N(a)×Rn → Rn. A general principle for the existence of at least one solution with graph staying for very k ∈ N(a) in a previously prescribed domain is formulated. Such solutions are defined by means f the corresponding initial data and their existence is proved by means of retract type approach. For he development of this approach a notion of egress type points lying on the defined boundary of a iven domain and with respect to the system considered is utilized. Unlike previous investigations,the boundary can contain points which are not points of egress type, too. Examples are inserted to llustrate the obtained result.

  16. High-pressure crystal growth and electromagnetic properties of 5d double-perovskite Ca3OsO6

    International Nuclear Information System (INIS)

    Single crystals of the osmium-containing compound Ca3OsO6 have been successfully grown under high-pressure conditions, for the first time. The crystal structure of Ca3OsO6 were characterized as an ordered double-perovskite structure of space group P21/n with the Ca and Os atoms being fully ordered at the perovskite B-site. The electromagnetic analysis shows that the crystal exhibits a semiconductor-like behavior below 300 K and undergoes an antiferromagnetic transition at 50 K. - Graphical Abstract: Schematic image of crystal structure of Ca3OsO6 as determined by X-ray diffraction, where the gray and black octahedrons are occupied by Ca and Os, respectively. Top inset reveals an optic image of a typical Ca3OsO6 single crystal. Highlights: ► Single crystals of Ca3OsO6 have been successfully grown under high-pressure. ► Ca3OsO6 crystalizes into an ordered double-perovskite structure. ► The Ca3OsO6 undergoes an antiferromagnetic transition at 50 K

  17. Retractable tube design issues in ITER CXRS UPP no. 3

    International Nuclear Information System (INIS)

    Highlights: ► The retractable tube is located in the upper port plug no. 3 of ITER core charge exchange recombination spectroscopy (cCXRS) that carries the cleaning system of the first mirror. ► Various manufacturing methods were investigated for the proper layout of the tube cooling structure. ► The tube support boundary conditions were examined. ► A flexible compensator element was developed between the floating and structural flange of the tube. -- Abstract: The retractable tube is located in the upper port plug no. 3 of ITER core charge exchange recombination spectroscopy (cCXRS), where it is surrounded by a set of mirrors, diagnostic shielding module (DSM), outer shell, cleaning device and shutter. Accordingly to the recent port plug concept the tube is an optional unit that carries the cleaning system of the first mirror. The cleaning device shall be a compact instrument at the tube head that influences the tube diameter primarily. Independently of the cleaning device the tube cooling channels and its proper support concept has to be developed. Various manufacturing methods are investigated for the proper layout of the tube cooling structure. They are the gun-drilled deep holes, the solid state bonded sheets forming cooling channels between the welded layers, ‘tube-in-tube’ approach. Most of them were analyzed in view of their thermal conditions. The tube support system design is a complex task, that has to take into account several boundary conditions and limitations. The tube must be compatible with the assumed ITER generic installation procedure, withstand the electromagnetic (EM) and thermal loads. Furthermore, the tube has to be exchanged several times during its lifetime. The paper summarizes the tube cooling layout possibilities and the assumptions on its support concepts

  18. Regulation of phenylacetic acid uptake is σ54 dependent in Pseudomonas putida CA-3

    Directory of Open Access Journals (Sweden)

    O' Mahony Mark M

    2011-10-01

    Full Text Available Abstract Background Styrene is a toxic and potentially carcinogenic alkenylbenzene used extensively in the polymer processing industry. Significant quantities of contaminated liquid waste are generated annually as a consequence. However, styrene is not a true xenobiotic and microbial pathways for its aerobic assimilation, via an intermediate, phenylacetic acid, have been identified in a diverse range of environmental isolates. The potential for microbial bioremediation of styrene waste has received considerable research attention over the last number of years. As a result the structure, organisation and encoded function of the genes responsible for styrene and phenylacetic acid sensing, uptake and catabolism have been elucidated. However, a limited understanding persists in relation to host specific regulatory molecules which may impart additional control over these pathways. In this study the styrene degrader Pseudomonas putida CA-3 was subjected to random mini-Tn5 mutagenesis and mutants screened for altered styrene/phenylacetic acid utilisation profiles potentially linked to non-catabolon encoded regulatory influences. Results One mutant, D7, capable of growth on styrene, but not on phenylacetic acid, harboured a Tn5 insertion in the rpoN gene encoding σ54. Complementation of the D7 mutant with the wild type rpoN gene restored the ability of this strain to utilise phenylacetic acid as a sole carbon source. Subsequent RT-PCR analyses revealed that a phenylacetate permease, PaaL, was expressed in wild type P. putida CA-3 cells utilising styrene or phenylacetic acid, but could not be detected in the disrupted D7 mutant. Expression of plasmid borne paaL in mutant D7 was found to fully restore the phenylacetic acid utilisation capacity of the strain to wild type levels. Bioinformatic analysis of the paaL promoter from P. putida CA-3 revealed two σ54 consensus binding sites in a non-archetypal configuration, with the transcriptional start site

  19. The antiferromagnetic insulator Ca3FeRhO6: characterization and electronic structure calculations

    OpenAIRE

    Eyert, V.; Schwingenschloegl, U.; Fresard, R.; Maignan, A.; Martin, C.; Nguyen, N.; Hackenberger, C.; Kopp, T.

    2006-01-01

    We investigate the antiferromagnetic insulating nature of Ca3FeRhO6 both experimentally and theoretically. Susceptibility measurements reveal a Neel temperature T_N = 20 K, and a magnetic moment of 5.3 muB/f. u., while Moessbauer spectroscopy strongly suggests that the Fe ions, located in trigonal prismatic sites, are in a 3+ high spin state. Transport measurements display a simple Arrhenius law, with an activation energy of 0.2 eV. The experimental results are interpreted with LSDA band stru...

  20. Oxygen consumption rates during three different neuronal activity states in the hippocampal CA3 network

    OpenAIRE

    Huchzermeyer, Christine; Berndt, Nikolaus; Holzhütter, Hermann-Georg; Kann, Oliver

    2012-01-01

    The brain is an organ with high metabolic rate. However, little is known about energy utilization during different activity states of neuronal networks. We addressed this issue in area CA3 of hippocampal slice cultures under well-defined recording conditions using a 20% O2 gas mixture. We combined recordings of local field potential and interstitial partial oxygen pressure (pO2) during three different activity states, namely fast network oscillations in the gamma-frequency band (30 to 100 Hz)...

  1. High-temperature stability of thermoelectric Ca3Co4O9 thin films

    DEFF Research Database (Denmark)

    Brinks, P.; Van Nong, Ngo; Pryds, Nini;

    2015-01-01

    An enhanced thermal stability in thermoelectric Ca3Co4O9 thin films up to 550 °C in an oxygen rich environment was demonstrated by high-temperature electrical and X-ray diffraction measurements. In contrast to generally performed heating in helium gas, it is shown that an oxygen/helium mixture...... provides sufficient thermal contact, while preventing the previously disregarded formation of oxygen vacancies. Combining thermal cycling with electrical measurements proves to be a powerful tool to study the real intrinsic thermoelectric behaviour of oxide thin films at elevated temperatures. © 2015 AIP...

  2. Regulation of phenylacetic acid uptake is sigma54 dependent in Pseudomonas putida CA-3.

    LENUS (Irish Health Repository)

    O' Leary, Niall D

    2011-10-13

    Abstract Background Styrene is a toxic and potentially carcinogenic alkenylbenzene used extensively in the polymer processing industry. Significant quantities of contaminated liquid waste are generated annually as a consequence. However, styrene is not a true xenobiotic and microbial pathways for its aerobic assimilation, via an intermediate, phenylacetic acid, have been identified in a diverse range of environmental isolates. The potential for microbial bioremediation of styrene waste has received considerable research attention over the last number of years. As a result the structure, organisation and encoded function of the genes responsible for styrene and phenylacetic acid sensing, uptake and catabolism have been elucidated. However, a limited understanding persists in relation to host specific regulatory molecules which may impart additional control over these pathways. In this study the styrene degrader Pseudomonas putida CA-3 was subjected to random mini-Tn5 mutagenesis and mutants screened for altered styrene\\/phenylacetic acid utilisation profiles potentially linked to non-catabolon encoded regulatory influences. Results One mutant, D7, capable of growth on styrene, but not on phenylacetic acid, harboured a Tn5 insertion in the rpoN gene encoding σ54. Complementation of the D7 mutant with the wild type rpoN gene restored the ability of this strain to utilise phenylacetic acid as a sole carbon source. Subsequent RT-PCR analyses revealed that a phenylacetate permease, PaaL, was expressed in wild type P. putida CA-3 cells utilising styrene or phenylacetic acid, but could not be detected in the disrupted D7 mutant. Expression of plasmid borne paaL in mutant D7 was found to fully restore the phenylacetic acid utilisation capacity of the strain to wild type levels. Bioinformatic analysis of the paaL promoter from P. putida CA-3 revealed two σ54 consensus binding sites in a non-archetypal configuration, with the transcriptional start site being resolved by

  3. Oxygen potentials and phase equilibria in the system Ca–Co–O and thermodynamic properties of Ca3Co2O6 and Ca3Co4O9.163

    International Nuclear Information System (INIS)

    Oxygen potentials established by the equilibrium between three condensed phases, CaOss+CoOss+Ca3Co2O6 and CoOss+Ca3Co2O6+Ca3Co3.93+αO9.36−δ, are measured as a function of temperature using solid-state electrochemical cells incorporating yttria-stabilized zirconia as the electrolyte and pure oxygen as the reference electrode. Cation non-stoichiometry and oxygen non-stoichiometry in Ca3Co3.93+αO9.36−δ are determined using different techniques under defined conditions. Decomposition temperatures and thermodynamic properties of Ca3Co2O6 and Ca3Co4O9.163 are calculated from the results. The standard entropy and enthalpy of formation of Ca3Co2O6 at 298.15 K are evaluated. Using thermodynamic data from this study and auxiliary information from the literature, phase diagram for the ternary system Ca–Co–O is computed. Isothermal sections at representative temperatures are displayed to demonstrate the evolution of phase relations with temperature. - Graphical abstract: Isothermal section of the phase diagram of the system Ca–Co–O at 1250 K. - Highlights: • Improved definition of cation and oxygen nonstoichiometry of Ca3Co3.93+αO9.36−δ. • Measurement of ΔμO2 associated with two 3-phase fields as a function of temperature. • Use of solid-state electrochemical cells for accurate measurement of ΔμO2. • Decomposition temperatures and thermodynamic properties for ternary oxides. • Characterization of ternary phase diagram of the system Ca–Co–O

  4. Pycnogenol protects CA3-CA1 synaptic function in a rat model of traumatic brain injury.

    Science.gov (United States)

    Norris, Christopher M; Sompol, Pradoldej; Roberts, Kelly N; Ansari, Mubeen; Scheff, Stephen W

    2016-02-01

    Pycnogenol (PYC) is a patented mix of bioflavonoids with potent anti-oxidant and anti-inflammatory properties. Previously, we showed that PYC administration to rats within hours after a controlled cortical impact (CCI) injury significantly protects against the loss of several synaptic proteins in the hippocampus. Here, we investigated the effects of PYC on CA3-CA1 synaptic function following CCI. Adult Sprague-Dawley rats received an ipsilateral CCI injury followed 15 min later by intravenous injection of saline vehicle or PYC (10 mg/kg). Hippocampal slices from the injured (ipsilateral) and uninjured (contralateral) hemispheres were prepared at seven and fourteen days post-CCI for electrophysiological analyses of CA3-CA1 synaptic function and induction of long-term depression (LTD). Basal synaptic strength was impaired in slices from the ipsilateral, relative to the contralateral, hemisphere at seven days post-CCI and susceptibility to LTD was enhanced in the ipsilateral hemisphere at both post-injury timepoints. No interhemispheric differences in basal synaptic strength or LTD induction were observed in rats treated with PYC. The results show that PYC preserves synaptic function after CCI and provides further rationale for investigating the use of PYC as a therapeutic in humans suffering from neurotrauma. PMID:26607913

  5. Thermoelectric transport in the layered Ca3Co4-xRhxO9 single crystals

    Science.gov (United States)

    Ikeda, Yusuke; Saito, Kengo; Okazaki, Ryuji

    2016-06-01

    We have examined an isovalent Rh substitution effect on the transport properties of the thermoelectric oxide Ca3Co4O9 using single-crystalline form. With increasing Rh content x, both the electrical resistivity and the Seebeck coefficient change systematically up to x = 0.6 for Ca3Co4-xRhxO9 samples. In the Fermi-liquid regime where the resistivity behaves as ρ = ρ 0 + A T 2 around 120 K, the A value decreases with increasing Rh content, indicating that the correlation effect is weakened by Rh 4d electrons with extended orbitals. We find that, in contrast to such a weak correlation effect observed in the resistivity of Rh-substituted samples, the low-temperature Seebeck coefficient is increased with increasing Rh content, which is explained with a possible enhancement of a pseudogap associated with the short-range order of spin density wave. In high-temperature range above room temperature, we show that the resistivity is largely suppressed by Rh substitution while the Seebeck coefficient becomes almost temperature-independent, leading to a significant improvement of the power factor in Rh-substituted samples. This result is also discussed in terms of the differences in the orbital size and the associated spin state between Co 3d and Rh 4d electrons.

  6. Dopamine D3 receptors inhibit hippocampal gamma oscillations by disturbing CA3 pyramidal cell firing synchrony

    Directory of Open Access Journals (Sweden)

    Clément E. Lemercier

    2016-01-01

    Full Text Available Cortical gamma oscillations are associated with cognitive processes and are altered in several neuropsychiatric conditions such as schizophrenia and Alzheimer’s disease. Since dopamine D3 receptors are possible targets in treatment of these conditions, it is of great importance to understand their role in modulation of gamma oscillations. The effect of D3 receptors on gamma oscillations and the underlying cellular mechanisms were investigated by extracellular local field potential and simultaneous intracellular sharp micro-electrode recordings in the CA3 region of the hippocampus in vitro. D3 receptors decreased the power and broadened the bandwidth of gamma oscillations induced by acetylcholine or kainate. Blockade of the D3 receptors resulted in faster synchronization of the oscillations, suggesting that endogenous dopamine in the hippocampus slows down the dynamics of gamma oscillations by activation of D3 receptors. Investigating the underlying cellular mechanisms for these effects showed that D3 receptor activation decreased the rate of action potentials during gamma oscillations and reduced the precision of the action potential phase coupling to the gamma cycle in CA3 pyramidal cells. The results may offer an explanation how selective activation of D3 receptors may impair cognition and how, in converse, D3 antagonists may exert pro-cognitive and antipsychotic effects.

  7. Dopamine D3 Receptors Inhibit Hippocampal Gamma Oscillations by Disturbing CA3 Pyramidal Cell Firing Synchrony.

    Science.gov (United States)

    Lemercier, Clément E; Schulz, Steffen B; Heidmann, Karin E; Kovács, Richard; Gerevich, Zoltan

    2015-01-01

    Cortical gamma oscillations are associated with cognitive processes and are altered in several neuropsychiatric conditions such as schizophrenia and Alzheimer's disease. Since dopamine D3 receptors are possible targets in treatment of these conditions, it is of great importance to understand their role in modulation of gamma oscillations. The effect of D3 receptors on gamma oscillations and the underlying cellular mechanisms were investigated by extracellular local field potential and simultaneous intracellular sharp micro-electrode recordings in the CA3 region of the hippocampus in vitro. D3 receptors decreased the power and broadened the bandwidth of gamma oscillations induced by acetylcholine or kainate. Blockade of the D3 receptors resulted in faster synchronization of the oscillations, suggesting that endogenous dopamine in the hippocampus slows down the dynamics of gamma oscillations by activation of D3 receptors. Investigating the underlying cellular mechanisms for these effects showed that D3 receptor activation decreased the rate of action potentials (APs) during gamma oscillations and reduced the precision of the AP phase coupling to the gamma cycle in CA3 pyramidal cells. The results may offer an explanation how selective activation of D3 receptors may impair cognition and how, in converse, D3 antagonists may exert pro-cognitive and antipsychotic effects. PMID:26779018

  8. Shubnikov-de Haas oscillations in Ca3Ru2O7 under pressure

    International Nuclear Information System (INIS)

    The bilayer ruthenate Ca3Ru2O7 undergoes a series of phase transitions on cooling, which lead to a low carrier density state at low temperature. Hydrostatic pressure is applied on this material in order to track the Fermi surface whilst tuning and ultimately suppressing the high temperature phase transitions. Quantum oscillations in the Hall component of Ca3Ru2O7 are investigated as a function pressure using a piston-cylinder cell. As the pressure is increased, the oscillation frequency decreases systematically, suggesting that the Fermi pockets shrink. Owing to the size of the frequencies and to the non-linear background, the evolution of the effective masses cannot be determined accurately enough to extract a trend other than that they remain of the order of 0.6me. Further work at higher pressures is under way, using anvil cells, to track the evolution of the Fermi surface through the pressures where the magnetic and structural transitions eventually are suppressed.

  9. Involvement of myosin light-chain kinase in endothelial cell retraction

    Energy Technology Data Exchange (ETDEWEB)

    Wysolmerski, R.B.; Lagunoff, D. (Saint Louis Univ. School of Medicine, MO (USA))

    1990-01-01

    Permeabilized bovine pulmonary artery endothelial cell monolayers were used to investigate the mechanism of endothelial cell retraction. Postconfluent endothelial cells permeabilized with saponin retracted upon exposure to ATP and Ca{sup 2+}. Retraction was accompanied by thiophosphorylation of 19,000-Da myosin light chains when adenosine 5'-(gamma-({sup 35}S)thio)triphosphate was included in the medium. Both retraction and thiophosphorylation of myosin light chains exhibited a graded quantitative dependence on Ca{sup 2+}. When permeabilized monolayers were extracted in buffer D containing 100 mM KCl and 30 mM MgCl2 for 30 min, the cells failed to retract upon exposure to ATP and Ca{sup 2+}, and no thiophosphorylation of myosin light chains occurred. The ability both to retract and to thiophosphorylate myosin light chains was restored by the addition to the permeabilized, extracted cells of myosin light-chain kinase and calmodulin together but not by either alone. These studies indicate that endothelial cell retraction, as does smooth muscle contraction, depends on myosin light-chain kinase phosphorylation of myosin light chains.

  10. Electromagnetic panel deployment and retraction using the geomagnetic field in LEO satellite missions

    Science.gov (United States)

    Inamori, Takaya; Sugawara, Yoshiki; Satou, Yasutaka

    2015-12-01

    Increasingly, spacecraft are installed with large-area structures that are extended and deployed post-launch. These extensible structures have been applied in several missions for power generation, thermal radiation, and solar propulsion. Here, we propose a deployment and retraction method using the electromagnetic force generated when the geomagnetic field interacts with electric current flowing on extensible panels. The panels are installed on a satellite in low Earth orbit. Specifically, electrical wires placed on the extensible panels generate magnetic moments, which interfere with the geomagnetic field. The resulting repulsive and retraction forces enable panel deployment and retraction. In the proposed method, a satellite realizes structural deployment using simple electrical wires. Furthermore, the satellite can achieve not only deployment but also retraction for avoiding damage from space debris and for agile attitude maneuvers. Moreover, because the proposed method realizes quasi-static deployment and the retraction of panels by electromagnetic forces, low impulsive force is exerted on fragile panels. The electrical wires can also be used to detect the panel deployment and retraction and generate a large magnetic moment for attitude control. The proposed method was assessed in numerical simulations based on multibody dynamics. Simulation results shows that a small cubic satellite with a wire current of 25 AT deployed 4 panels (20 cm × 20 cm) in 500 s and retracted 4 panels in 100 s.

  11. Disappearance of Ising nature in Ca3ZnMnO6 studied by high-field ESR

    International Nuclear Information System (INIS)

    High-field electron spin resonance measurements of an antiferromagnet Ca3ZnMnO6 isostructure, with the Ising-chain multiferroic Ca3CoMnO6, have been carried out. Two distinct resonance modes were observed below TN = 25 K, which is well explained by conventional antiferromagnetic resonance theory with easy-plane anisotropy. The zero-field spin gap is derived to be about 166 GHz, originating from the easy-plane anisotropy and exchange interaction. Our result suggests that the Dzyaloshinsky–Moriya interaction, which may induce spin canting, is absent. Disappearance of Ising anisotropy in Ca3ZnMnO6 suggests that the Co4+ ion, as well as the Co–Mn superexchange, plays an important role for the Ising nature in Ca3CoMnO6. (paper)

  12. A Hopfield-like hippocampal CA3 neural network model for studying associative memory in Alzheimer's disease

    Institute of Scientific and Technical Information of China (English)

    Wangxiong Zhao; Qingli Qiao; Dan Wang

    2010-01-01

    Associative memory, one of the major cognitive functions in the hippocampal CA3 region, includes auto-associative memory and hetero-associative memory. Many previous studies have shown that Alzheimer's disease (AD) can lead to loss of functional synapses in the central nervous system, and associative memory functions in patients with AD are often impaired, but few studies have addressed the effect of AD on hetero-associative memory in the hippocampal CA3 region. In this study, based on a simplified anatomical structure and synaptic connections in the hippocampal CA3 region, a three-layered Hopfield-like neural network model of hippocampal CA3 was proposed and then used to simulate associative memory functions in three circumstances: normal, synaptic deletion and synaptic compensation, according to Ruppin's synaptic deletion and compensation theory. The influences of AD on hetero-associative memory were further analyzed. The simulated results showed that the established three-layered Hopfield-like neural network model of hippocampal CA3 has both auto-associative and hetero-associative memory functions. With increasing synaptic deletion level, both associative memory functions were gradually impaired and the mean firing rates of the neurons within the network model were decreased. With gradual increasing synaptic compensation, the associative memory functions of the network were improved and the mean firing rates were increased. The simulated results suggest that the Hopfield-like neural network model can effectively simulate both associative memory functions of the hippocampal CA3 region. Synaptic deletion affects both auto-associative and hetero-associative memory functions in the hippocampal CA3 region, and can also result in memory dysfunction. To some extent, synaptic compensation measures can offset two kinds of associative memory dysfunction caused by synaptic deletion in the hippocampal CA3 area.

  13. Development of dendrite polarity in Drosophila neurons

    Directory of Open Access Journals (Sweden)

    Hill Sarah E

    2012-10-01

    Full Text Available Abstract Background Drosophila neurons have dendrites that contain minus-end-out microtubules. This microtubule arrangement is different from that of cultured mammalian neurons, which have mixed polarity microtubules in dendrites. Results To determine whether Drosophila and mammalian dendrites have a common microtubule organization during development, we analyzed microtubule polarity in Drosophila dendritic arborization neuron dendrites at different stages of outgrowth from the cell body in vivo. As dendrites initially extended, they contained mixed polarity microtubules, like mammalian neurons developing in culture. Over a period of several days this mixed microtubule array gradually matured to a minus-end-out array. To determine whether features characteristic of dendrites were localized before uniform polarity was attained, we analyzed dendritic markers as dendrites developed. In all cases the markers took on their characteristic distribution while dendrites had mixed polarity. An axonal marker was also quite well excluded from dendrites throughout development, although this was perhaps more efficient in mature neurons. To confirm that dendrite character could be acquired in Drosophila while microtubules were mixed, we genetically disrupted uniform dendritic microtubule organization. Dendritic markers also localized correctly in this case. Conclusions We conclude that developing Drosophila dendrites initially have mixed microtubule polarity. Over time they mature to uniform microtubule polarity. Dendrite identity is established before the mature microtubule arrangement is attained, during the period of mixed microtubule polarity.

  14. Cationic disorder and Mn3+/Mn4+ charge ordering in the B′ and B″ sites of Ca3Mn2NbO9 perovskite: a comparison with Ca3Mn2WO9

    International Nuclear Information System (INIS)

    We describe the preparation, crystal structure determination, magnetic and transport properties of two novel Mn-containing perovskites, with a different electronic configuration for Mn atoms located in B site. Ca3Mn3+2WO9 and Ca3Mn3+/4+2NbO9 were synthesized by standard ceramic procedures; the crystallographic structure was studied from X-ray powder diffraction (XRPD) and neutron powder diffraction (NPD). Both phases exhibit a monoclinic symmetry (S.G.: P21/n); Ca3Mn2WO9 presents a long-range ordering over the B sites, whereas Ca3Mn2NbO9 is strongly disordered. By “in-situ” NPD, the temperature evolution of the structure study presents an interesting evolution in the octahedral size (〈Mn–O〉) for Ca3Mn2NbO9, driven by a charge ordering effect between Mn3+ and Mn4+ atoms, related to the anomaly observed in the transport measurements at T≈160 K. Both materials present a magnetic order below TC=30 K and 40 K for W and Nb materials, respectively. The magneto-transport measurements display non-negligible magnetoresistance properties in the paramagnetic regime. - Graphical abstract: Comparison between the octahedron size and the magnetic behaviour for Ca3Mn2NbO9 in the temperature region where the charge and magnetic order occur. Display Omitted - Highlights: • Two novel Mn-containing double perovskites were obtained by solid-state reactions. • Both double perovskites are monoclinic (P21/n) determined by XRPD and NPD. • Ca3Mn2WO9 contains Mn3+ while Ca3Mn2NbO9 includes mixed-valence cations Mn3+/Mn4+. • Ca3Mn2NbO9 presents a charge-ordering effect between Mn3+ and Mn4+ evidenced by NPD. • The magnetic and transport studies evidenced the charge ordering in Ca3Mn2NbO9

  15. Synthesis, structure and Eu2+-doped luminescence properties of bromosilicate compound Ca3SiO4Br2

    International Nuclear Information System (INIS)

    The bromosilicate Ca3SiO4Br2 crystal has been grown, and this compound crystallizes in triclinic symmetry, space group P-1 (No. 2), with unit cell parameters: a=8.0051(18) Å, b=8.720(3) Å, c=11.749(3)Å, α=69.07(0)°, β=89.98(0)°, γ=75.46(0)°, and cell volume V=737.88(1 9 6)Å3, Z=3. The unit cell of the Ca3SiO4Br2 crystal is composed of the alternating layers of CaBr2 and Ca2SiO4, therefore, the luminescence of Ca3SiO4Br2:Eu2+ gives a broad emission band centered at 469 nm with some asymmetry on the long wavelength side with different coordination environment. Their detailed photoluminescence (PL) properties, PL decay curves and the temperature dependent PL behavior were also discussed. - Highlights: ► The Ca3SiO4Br2 crystal has been grown and the structure has been analyzed. ► Ca3SiO4Br2:Eu2+ gives a blue emission band centered at 469 nm. ► PL decay curves and the temperature dependent PL behavior of Ca3SiO4Br2:Eu2+ have been discussed.

  16. Dendrite Injury Triggers DLK-Independent Regeneration

    Directory of Open Access Journals (Sweden)

    Michelle C. Stone

    2014-01-01

    Full Text Available Axon injury triggers regeneration through activation of a conserved kinase cascade, which includes the dual leucine zipper kinase (DLK. Although dendrites are damaged during stroke, traumatic brain injury, and seizure, it is not known whether mature neurons monitor dendrite injury and initiate regeneration. We probed the response to dendrite damage using model Drosophila neurons. Two larval neuron types regrew dendrites in distinct ways after all dendrites were removed. Dendrite regeneration was also triggered by injury in adults. Next, we tested whether dendrite injury was initiated with the same machinery as axon injury. Surprisingly, DLK, JNK, and fos were dispensable for dendrite regeneration. Moreover, this MAP kinase pathway was not activated by injury to dendrites. Thus, neurons respond to dendrite damage and initiate regeneration without using the conserved DLK cascade that triggers axon regeneration.

  17. Dendritic cells in asthma.

    Science.gov (United States)

    van Helden, Mary J; Lambrecht, Bart N

    2013-12-01

    The lungs are constantly exposed to antigens, most of which are non-pathogenic and do not require the induction of an immune response. Dendritic cells (DCs) are situated at the basolateral site of the lungs and continuously scan the environment to detect the presence of pathogens and subsequently initiate an immune response. They are a heterogeneous population of antigen-presenting cells that exert specific functions. Compelling evidence is now provided that DCs are both sufficient and necessary to induce allergic responses against several inhaled harmless allergens. How various DC subsets exactly contribute to the induction of allergic asthma is currently a subject of intense investigation. We here review the current progress in this field. PMID:24455765

  18. A structural change in Ca3Co4O9 associated with enhanced thermoelectric properties

    International Nuclear Information System (INIS)

    Temperature dependent electrical resistivity, crystal structure and heat capacity measurements reveal a resistivity drop and electrical transport behavior change corresponding to a structural change near 400 K in Ca3Co4O9. The lattice parameter c varies smoothly with increasing temperature while anomalies in a, b1 and b2 lattice parameters occur near 400 K. The Ca site in the Ca2CoO3 block becomes distorted and a change in electrical transport behavior is found above 400 K. Resistivity and heat capacity measurements as a function of temperature under magnetic field combined with Co L-edge x-ray absorption spectra reveal only a weak spin contribution to this change. Reduced resistivity associated with the structural change enhances the thermoelectric properties at moderately high temperatures and points to the electrical transport behavior change as a mechanism for improved ZT in this thermoelectric oxide.

  19. Scintillation characteristics of Tm3+ in Ca3(BO3)2 crystals

    International Nuclear Information System (INIS)

    Basic optical properties and radiation responses of undoped, Tm3+ 1.0% and 2.0% activated Ca3(BO3)2 (CBO) crystalline scintillator prepared by the micro-pulling down (μ-PD) method are reported. Tm3+: CBO crystals showed three weak absorption bands around 190, 260 and 350 nm, owing to the Tm3+ 4f–4f transition. Strong blue luminescence peaks at 360 and 460 nm which are ascribed to the 1D2–3H6 and 1D2–3F4 transitions of Tm3+ respectively were observed under 241Am 5.5 MeV α-ray excitation. The scintillation light yield of 2.0% Tm3+-doped CBO crystal was evaluated to be about 250 ph/n from the 252Cf excited pulse height spectrum.

  20. Anisotropic laser properties of Yb:Ca3La2(BO3)4 disordered crystal

    Science.gov (United States)

    Wang, Lisha; Xu, Honghao; Pan, Zhongben; Han, Wenjuan; Chen, Xiaowen; Liu, Junhai; Yu, Haohai; Zhang, Huaijin

    2016-08-01

    A study is carried out experimentally on the anisotropy in the laser action of Yb:Ca3La2(BO3)4 disordered crystal, demonstrated with the output coupling changed over a wide range from 0.5% to 40%. Complex polarization state variation with output coupling and evolution with pump power are observed in the laser operation achieved with a- and c-cut crystal samples. A maximum output power of 8.2 W is produced at wavelengths around 1043 nm, with an incident pump power of 24.9 W, the optical-to-optical efficiency being 33%. The polarized absorption and emission cross section spectra are also presented.

  1. MRI findings in Duane's ocular retraction syndrome

    International Nuclear Information System (INIS)

    Aim: To investigate the innervation pattern of extra-ocular muscles in patients with clinically diagnosed Duane's ocular retraction syndrome (DRS) using magnetic resonance imaging (MRI). Materials and methods: The study population consisted of 11 patients. Six patients had type I DRS (eight eyes), four patients had type II DRS (five eyes) and one patient had inverse DRS. Images were acquired using a Siemens 3 T MRI system. The type of DRS, corresponding innervation findings, and condition of the affected muscles were evaluated by two experienced neuroradiologists in consensus. Results: All patients with clinically diagnosed DRS type I showed absence of the abducens nerve (CN6), hypoplasia of the superior oblique muscle (SOM), and aberrant innervation of lateral rectus muscle (LRM) by an extra branch of oculomotor nerve (CN3). All patients with type II DRS show dual-innervation of the LRM (by CN6 and an aberrant CN3 branch) and hypoplasia of SOM. The single patient with inverse DRS showed hypoplasia of CN3, the medial rectus muscle (MRM), the inferior rectus muscle (IRM), and the inferior oblique muscle (IOM). Conclusion: Each type of DRS has characteristic MRI appearances. Therefore, MRI is a useful diagnostic tool for the confirmation and classification of suspected cases of DRS

  2. A retractable electron emitter for the creation of unperturbed pure electron plasmas

    Science.gov (United States)

    Berkery, John W.; Pedersen, Thomas Sunn; Sampedro, Luis

    2007-01-01

    A retractable electron emitter has been constructed for the creation of unperturbed pure electron plasmas on magnetic surfaces in the Columbia Non-neutral Torus stellarator. The previous method of electron emission using emitters mounted on stationary rods limited the confinement time to 20 ms. A pneumatically driven system that can retract from the magnetic axis to the last closed flux surface in less than 20 ms while filling the surfaces with electrons was designed. The motion of the retractable emitter was modeled with a system of dynamical equations. The measured position versus time of the emitter agrees well with the model and the fastest axis-to-edge retraction was measured to be 20 ms with 40 psig helium gas driving the pneumatic piston.

  3. Pars tensa retraction pockets in children: treatment by excision and ventilation tube insertion.

    Science.gov (United States)

    Srinivasan, V; Banhegyi, G; O'Sullivan, G; Sherman, I W

    2000-08-01

    Tympanic membrane retraction pockets involving the pars tensa are not uncommon in clinical practice. Recurrent infections, ossicular erosion and cholesteatoma are the recognized sequelae. The management options include surveillance, medical treatment and surgery. The surgical procedures range from grommet insertion to extensive tympanoplasty procedures. We report our experience with simple excision and grommet insertion, performed in 31 ears in 26 patients as day cases. The follow-up ranged from 8 to 34 months with a mean of 16 months. The procedure was successful in 23 ears (success rate of 74%). Recurrence of retraction occurred in seven ears and in one ear there was a persistent perforation. Age, previous grommet insertion and severity of retraction did not have a statistically significant influence on the final outcome. We conclude that excision and grommet insertion is a simple, safe and efficient procedure for the management of tympanic membrane retraction pockets and can be considered in preference to extensive tympanoplasty. PMID:10971530

  4. Retraction Note: Radiation Sialadenitis Induced by High-dose Radioactive Iodine Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Shin Young; Lee, Jaetae [Kyungpook National Univ. Hospital, Daegu (Korea, Republic of)

    2014-06-15

    The senior author (J. Lee) and the first author (S. Y. Jeong) have retracted this review article due to misconduct. They have discovered multiple instances of misreferencing and misquotation in the text which raise the concern of potential plagiarism.

  5. Retraction Note: Radiation Sialadenitis Induced by High-dose Radioactive Iodine Therapy

    International Nuclear Information System (INIS)

    The senior author (J. Lee) and the first author (S. Y. Jeong) have retracted this review article due to misconduct. They have discovered multiple instances of misreferencing and misquotation in the text which raise the concern of potential plagiarism

  6. Bilateral inverse Duane′s retraction syndrome-A case report

    Directory of Open Access Journals (Sweden)

    Chatterjee Pranab

    1991-01-01

    Full Text Available Duane′s retraction syndrome is a well known congenital musculo-facial anomaly. Various explanations have been given for the aetiology of this syndrome. Inverse Duane′s retraction syndrome is a condition with reverse clinical features. Abduction of the affected eye is possible to some extent and is accompanied by retraction of the eyeball, narrowing of the palpebral fissure and pseudoptosis. There may be some restriction of movement on adduction. The primary lesion is suspected to be in the medial rectus muscle. Frequently the muscle is found to be entrapped following trauma to the medial wall of the orbit. A case of bilateral inverse Duane′s retraction syndrome and convergent squint along with left-sided perceptive deafness is reported. As is usually the case there was no structural abnormality or entrapment of the muscle from trauma.

  7. Time-Dependent Response of Polypropylene/Clay Nanocomposites Under Tension and Retraction

    DEFF Research Database (Denmark)

    Drozdov, Aleksey; Christiansen, Jesper de Claville

    2013-01-01

    Observations are reported in relaxation tests under tension and retraction on polypropylene/clay nanocomposites with various contents of filler. A two-phase constitutive model is developed in cyclic viscoelasticity and viscoplasticity of nanocomposites. Adjustable parameters in the stress...

  8. Can dendritic cells see light?

    Science.gov (United States)

    Chen, Aaron C.-H.; Huang, Ying-Ying; Sharma, Sulbha K.; Hamblin, Michael R.

    2010-02-01

    There are many reports showing that low-level light/laser therapy (LLLT) can enhance wound healing, upregulate cell proliferation and has anti-apoptotic effects by activating intracellular protective genes. In the field of immune response study, it is not known with any certainty whether light/laser is proinflammatory or anti-inflammatory. Increasingly in recent times dendritic cells have been found to play an important role in inflammation and the immunological response. In this study, we try to look at the impact of low level near infrared light (810-nm) on murine bone-marrow derived dendritic cells. Changes in surface markers, including MHC II, CD80 and CD11c and the secretion of interleukins induced by light may provide additional evidence to reveal the mystery of how light affects the maturation of dendritic cells as well how these light-induced mature dendritic cells would affect the activation of adaptive immune response.

  9. RETRACTED: Magnetic properties of interfaces and multilayers based on thin antiferromagnetic oxide films

    Science.gov (United States)

    Finazzi, Marco; Duò, Lamberto; Ciccacci, Franco

    2007-09-01

    This article has been retracted at the request of the Editor-in-Chief and Authors. Please see Elsevier Policy on Article Withdrawal ( http://www.elsevier.com/locate/withdrawalpolicy). Reason: This article has been retracted because of copyright infringement. The authors plan to re-write the article to comply with copyright rules as soon as possible. A link to the re-written article will be added as soon as it is published.

  10. Calculatoin and experimental study of the retracting force for magnetic spring of two types

    OpenAIRE

    Tsivilitsin, V.; Milman, Yu.; V. Goncharuk; Bondar, I

    2014-01-01

    Designs for magnetic springs of two types have been proposed, and the methods of calculation of their retracting forces have been developed. Formulas are obtained for the retracting force in the main section of spring force characteristics. Experimental data are in good agreement with the results of theoretical calculations. The force characteristics of the proposed magnetic spring constructions can be varied for a specific application. The derived formulas are verified experimentally. Ways t...

  11. RETRACTED: Test Taking Strategies Instruction and Iranian EFL Learners’ Performance on International Language Tests

    Directory of Open Access Journals (Sweden)

    Mitra Ghabelju

    2013-01-01

    Full Text Available This article has been retracted: please see AIAC PTY.LTD. Policy on Publication Ethics and Publication Malpractice Statement.(http://www.aiac.org.au/journals/Subtemps/PEPMS.pdfThis article has been retracted based on the editorial decision upon conducting a thorough invesitigatiosn. It came to our notice that the author has plagirised this paper from an unpblished thesis carried out in Iran in 2010.

  12. Vision Therapy for Convergence Insufficiency Co-Incident with Duane Retraction Syndrome

    OpenAIRE

    Tonya Tira, OD; Graham Erickson, OD

    2014-01-01

    Background: Duane retraction syndrome (DRS) is a congenital ocular motility disorder characterized by limited abduction and/or limited adduction, globe retraction, and narrowing of the palpebral fissure on adduction. Because of adduction limits, these patients may also exhibit convergence insufficiency (CI). Symptomatic individuals can often benefit from optometric vision therapy (OVT). Although OVT does not treat the DRS itself, these procedural interventions can alleviate sympto...

  13. In Vivo Investigation of the Effectiveness of a Hyper-viscoelastic Model in Simulating Brain Retraction

    OpenAIRE

    Ping Li; Weiwei Wang; Chenxi Zhang; Yong An; Zhijian Song

    2016-01-01

    Intraoperative brain retraction leads to a misalignment between the intraoperative positions of the brain structures and their previous positions, as determined from preoperative images. In vitro swine brain sample uniaxial tests showed that the mechanical response of brain tissue to compression and extension could be described by the hyper-viscoelasticity theory. The brain retraction caused by the mechanical process is a combination of brain tissue compression and extension. In this paper, w...

  14. RETRACTED: Effect of flux jump on temperature distributions in high temperature superconductors

    Science.gov (United States)

    Zhao, Yu-Feng; He, Tian-Hu; Wang, Ping-Bo

    2010-10-01

    This article has been retracted: please see Elsevier Policy on Article Withdrawal ( http://www.elsevier.com/locate/withdrawalpolicy). This article is retracted at the request of the authors, due to admitted plagiarism of unpublished work of Tian-Hu He. He wishes to state that he was not involved in the publication process and his name was used on the paper without his knowledge.

  15. Magnetic resonance imaging of unilateral vertical retraction syndrome with atypical strabismus

    Institute of Scientific and Technical Information of China (English)

    ZHANG Cheng-yue; MAN Feng-yuan; WANG Zhen-chang; YU Gang; WU Qian; JIAO Yong-hong; ZHAO Kan-xing

    2011-01-01

    We report two patients with unilateral vertical retraction syndrome. Magnetic resonance imaging (MRI) of the orbits of the two cases showed similar size and location of the orbital structure, but with dramatically different strabismus type. MRI sagittal reconstruction of the orbits suggested that abnormal muscle tissue arised from the inferior rectus, which might be associated with retraction and narrowing of the palpebral fissure and atypical strabismus as well.

  16. Influence of acupuncture with exercise training on learning and memory functions, as well as microtubule-associated protein-2 and synaptophysin expression in the hippocampal CA3 region, in a rat model of cerebral infarction

    Institute of Scientific and Technical Information of China (English)

    Wei Jiang; Liubing Li; Min Yang; Yanzhen Bi; Kehui Hu; Peng Zhang; Yixin Shen; Qian Yu

    2011-01-01

    The present study was designed to determine microtubule-associated protein-2 and synaptophysin expression in the hippocampal CA3 region in a rat model of middle cerebral artery occlusion. The rats were treated with acupuncture at Baihui (GV 20), Qubin (GB 7), and Qianding (GV 21) points, in addition to exercise training. Results were compared with rats undergoing exercise training only. The Y-maze method and immunohistochemistry revealed decreased error frequency of passing through Y-maze, as well as significantly increased microtubule-associated protein-2 and synaptophysin expression, in the acupuncture with exercise training group compared with the model and exercise training groups after 5 weeks. Microtubule-associated protein-2 and synaptophysin expressions negatively correlated with error frequency of passing through the Y-maze. These results suggested that acupuncture combined with exercise training improved learning and memory functions in a rat model of cerebral infarction. The mechanisms of action were hypothesized to be associated with dendritic or synaptic plasticity in the ipsilateral hippocampal CA3 region.

  17. The Surgical Management of Tympanic Membrane Retraction Pockets Using Cartilage Tympanoplasty.

    Science.gov (United States)

    Kasbekar, Anand V; Patel, Virjen; Rubasinghe, Mihiri; Srinivasan, Venkat

    2014-12-01

    Evaluate the surgical treatment of tympanic membrane (TM) retractions with modified cartilage augmentation tympanoplasty. Retrospective review of subjects with Charachon stage II and III TM retractions who underwent modified cartilage augmentation tympanoplasty following excision of the retracted TM segment. Pre and postoperative symptoms and air-bone gaps were recorded. Forty two ears were included in the study. Twenty six ears were of stage II and 16 were stage III retractions. 35 (83 %) ears had ossicular erosion and cholesteatoma was found in 13 (31 %) ears, all in stage III retractions. Follow-up ranged 12-102 months. The air-bone gap (ABG) improved in 29 (76 %) and worsened in seven (19 %). Ears without cholesteatoma had a greater improvement in ABG. The results of our modified cartilage tympanoplasty technique are comparable to the published literature and should provide a safe and acceptable result. The high rate of cholesteatoma found preoperatively in stage III retractions advocates early surgical intervention. PMID:26396960

  18. PLACE CELL FORMATION BY GRID CELL CONVERGENCE IN THE DENDRITES OF A CA1 MODEL NEURON

    Directory of Open Access Journals (Sweden)

    Evangelia Pollali

    2014-04-01

    Full Text Available Place cells are pyramidal neurons in CA1 and CA3 regions of hippocampus which fire selectively when the animal is located in a particular place in space. CA1 place cells receive synaptic input from CA3 via the Schaffer collateral fibers to their proximal apical and basal dendrites and from the third layer of medial entorhinal cortex to their apical tuft dendrites. Both of these input pathways encode spatial information. Grid cells, which form the entorhinal input to CA1 cells, have a spatial firing field with multiple peaks which displays a regularly spaced, triangular grid pattern that covers the entire space of a given environment. Both grid and place cells are phase-modulated by theta rhythm and this modulation may be important for their spatial properties. Studying the formation of place cells is an important step in understanding how representation of the external environment is coded in neural networks that constitute spatial maps. It is not currently known how place fields emerge in CA1 neurons. An influential model of place cell formation predicts the convergence of various grid field inputs which combine linearly to create the place field output of CA1 cells. In this study, we constructed a model of CA1 place cell formation through the convergence of grid field inputs to the distal dendrites of our model neuron. We created a model of grid cell activity which represents the firing of grid cells modulated be the theta rhythm. We varied the number of different grid fields used as synaptic inputs to stimulate the distal dendrites of a biophysically constrained, detailed compartmental CA1 pyramidal cell model. In addition, inhibition was placed in both the distal and proximal dendrites. These inhibitory pathways are known to be active in different phases of the theta rhythm. We used this model to study the properties of CA1 place cell formation and to assess the output of the CA1 model cell during place cell activity. Additionally, we

  19. INFLUENCE OF ELECTROACUPUNCTURE ON THE ULTRASTRUCTURE OF CA3 REGION OF THE HIPPOCAMPUS IN VD RATS

    Institute of Scientific and Technical Information of China (English)

    YAN Bing; XU Neng-gui; HE Li-lei; TANG Chun-zhi; SHAO Ying

    2006-01-01

    Objective: To observe the effect of electroacupuncture (EA) on learning and memory abilities and ultrastructure of synapses in CA3 region of the hippocampus in vascular dementia (VD) rats. Methods: A total of 32 SD rats were randomized into control (sham-operation, n = 7), model (n = 7), EA (n = 9) and medication (n=9) groups. VD model was established by occlusion of the bilateral vertebral arteries (electrocoagulation) and bilateral common carotid arteries (occlusion for 5 min and reperfusion for 10 min, repeated the procedure for 3 times to induce global ischemia). EA (150 Hz, 1 mA) was applied to "Baihui"(百会GV 20), "Geshu"(膈俞 BL 17), "Pishu"(脾俞 BL 20) and "Shenshu"(肾俞 BL 23) for 20 min, once daily and continuously for 15 days. In medication group, the rats were fed with Nimotong (12 mg/kg), once daily and continuously for 15 days. Morris water maze method was used to test the animals' learning and memory abilities (latencies to find the hidden platform determined by place navigation trials, and latencies to cross on the location of the removed platform determined by spatial probe trials) after the treatment. Ultrastructural changes (numerical density, NA,surface density, Sv and volume density, Vv) of Gray type 1 synapses in CA3 region of the hippocampus were observed by using transmission electronic microscope and automatic image analysis system. Results: 1 ) Place navigation test showed that in comparison with control group, the average escape latency of VD group was significantly longer (P<0.01), while in comparison with VD group, the latencies of both EA and medication groups decreased significantly ( P<0.01 ). No significant difference was found between EA and medication groups in the escape latency (P>0.05). 2) Spatial probe-test displayed that in comparison with control group, the times which the animals crossed the target platform in VD group decreased significantly (P<0.01), while compared with VD group, those of both EA and

  20. Epitaxial growth of one-dimensional Ca3Co2O6 thin films prepared by pulsed laser deposition

    Science.gov (United States)

    Moubah, R.; Bouaine, A.; Ulhaq-Bouillet, C.; Schmerber, G.; Versini, G.; Barre, S.; Loison, J. L.; Drillon, M.; Colis, S.; Dinia, A.

    2007-10-01

    We report on the growth and structural properties of Ca3Co2O6 thin films deposited by pulsed laser ablation on SrTiO3 substrates heated at 700°C. In situ reflection high-energy electron diffraction and ex situ atomic force microscopy observations reveal that Ca3Co2O6 grows in a three-dimensional (3D) mode with a surface roughness of about 1.5nm rms. X-ray diffraction and cross-section transmission electron microscopy characterizations show that the deposited films are epitaxial without secondary phases and with a preferential growth orientation perpendicular to the (220) plane. Temperature dependent magnetization measurements reveal that the ferrimagnetic-ferromagnetic transition in the Ca3Co2O6 film is shifted toward higher temperatures with respect to the bulk cobaltite.

  1. Thermoelectric properties of Al substituted misfit cobaltite Ca3(Co1-xAlx)4O9 at low temperature

    Institute of Scientific and Technical Information of China (English)

    Yi Liu; Hong-mei Chen; Jin-lian Hu; Xu-bing Tang; Hai-jin Li; Wei Wang

    2014-01-01

    Thermoelectric properties of Al substituted compounds Ca3(Co1−xAlx)4O9 (x=0, 0.03, 0.05), prepared by a sol−gel process, have been investigated in the temperature range 305−20 K. The results indicate that after Al substitution for Co in Ca3(Co1−xAlx)4O9, the direct current electrical resistivity and thermopower increase due to the reduction of carrier concentration. Experiments show that Al substitution results in decreased lattice thermal conductivity. The figure of merit of temperature behavior suggests that Ca3(Co0.97Al0.03)4O9 would be a promising candidate thermoelectric material for high-temperature thermoelectric application.

  2. Enhancing the thermoelectric properties of Ca3Co4O9 thin films by Nb ion injection

    International Nuclear Information System (INIS)

    Highlights: •High quality Ca3Co4O9 thin films have been epitaxially grown on single crystal Al2O3 substrate. •Nb element was implanted into Ca3Co4O9 thin film by ion beam injection technique. •The effect of Nb doping was verified by resistivity measurement at room temperature. •Resistivity and Seebeck coefficient were measured in the temperature range 150–380 K. •The power factors of Ca3Co4O9 thin films increase when Nb doped. -- Abstract: High quality Ca3Co4O9 thin films have been grown epitaxially on single crystal Al2O3 substrates with pulsed laser deposition. Nb was implanted into the Ca3Co4O9 films using an ion beam injection technique. The microstructure of the thin films has been investigated by XRD, SEM and AFM. The epitaxial thin films were grown with the c-axis perpendicular to the substrate surface. The effect of Nb doping by ion beam injection was verified using resistivity measurements at room temperature. Resistivity and the Seebeck coefficient were also measured in the temperature range 150–380 K. The results indicate that the power factors of Ca3Co4O9 thin films increase when doped with Nb. When the concentration of doped Nb was 3.65 × 1019 atoms/cm3, the power factor of the thin films reached 0.10 mW/m K2 at room temperature, and it approached a maximum of 0.17 mW/m K2 at 380 K

  3. Metamagnetism of single crystal Ca3Ru2O7 in high magnetic fields

    International Nuclear Information System (INIS)

    Ca3Ru2O7, which has a double-layered structure related to perovskites and high-Tc cuprates, exhibits several coupled magnetic and transport phases. As-grown single crystals have nonmetallic conductivity for T M=48K, antiferromagnetic ordering up to TN=56 K and bad metal conductivity, linear in temperature for T > TN. The current study reveals a metamagnetic transition with an accompanying nonmetal to metal transition found in pulsed high magnetic fields (Hc=37 T) for the field directed perpendicular to the Ru-O planes in the 'hard' axis (0 0 1) direction of this highly anisotropic system. By contrast, the transition occurs at 6T for the field along the 'easy' axis (1 1 0). The resistivity for current along (1 1 0) or (0 0 1) is anisotropic in zero field at low temperatures but becomes isotropic with H > Hc applied along the easy axis, in contrast to results expected from Fermi-liquid models

  4. Hippocampal neurogenesis and dendritic plasticity support running-improved spatial learning and depression-like behaviour in stressed rats.

    Directory of Open Access Journals (Sweden)

    Suk-Yu Yau

    Full Text Available Exercise promotes hippocampal neurogenesis and dendritic plasticity while stress shows the opposite effects, suggesting a possible mechanism for exercise to counteract stress. Changes in hippocampal neurogenesis and dendritic modification occur simultaneously in rats with stress or exercise; however, it is unclear whether neurogenesis or dendritic remodeling has a greater impact on mediating the effect of exercise on stress since they have been separately examined. Here we examined hippocampal cell proliferation in runners treated with different doses (low: 30 mg/kg; moderate: 40 mg/kg; high: 50 mg/kg of corticosterone (CORT for 14 days. Water maze task and forced swim tests were applied to assess hippocampal-dependent learning and depression-like behaviour respectively the day after the treatment. Repeated CORT treatment resulted in a graded increase in depression-like behaviour and impaired spatial learning that is associated with decreased hippocampal cell proliferation and BDNF levels. Running reversed these effects in rats treated with low or moderate, but not high doses of CORT. Using 40 mg/kg CORT-treated rats, we further studied the role of neurogenesis and dendritic remodeling in mediating the effects of exercise on stress. Co-labelling with BrdU (thymidine analog /doublecortin (immature neuronal marker showed that running increased neuronal differentiation in vehicle- and CORT-treated rats. Running also increased dendritic length and spine density in CA3 pyramidal neurons in 40 mg/kg CORT-treated rats. Ablation of neurogenesis with Ara-c infusion diminished the effect of running on restoring spatial learning and decreasing depression-like behaviour in 40 mg/kg CORT-treated animals in spite of dendritic and spine enhancement. but not normal runners with enhanced dendritic length. The results indicate that both restored hippocampal neurogenesis and dendritic remodelling within the hippocampus are essential for running to counteract

  5. Effects of Synthesis and Spark Plasma Sintering Conditions on the Thermoelectric Properties of Ca3Co4O9+δ

    DEFF Research Database (Denmark)

    Wu, NingYu; Holgate, Tim; Van Nong, Ngo;

    2013-01-01

    Ca3Co4O9+δ samples were synthesized by solid-state (SS) and sol–gel (SG) reactions, followed by spark plasma sintering under different processing conditions. The synthesis process was optimized and the resulting materials characterized with respect to their microstructure, bulk density, and therm......Ca3Co4O9+δ samples were synthesized by solid-state (SS) and sol–gel (SG) reactions, followed by spark plasma sintering under different processing conditions. The synthesis process was optimized and the resulting materials characterized with respect to their microstructure, bulk density...

  6. Crystal Growth and Characterization of Ca3NbGa3Si2O14 Single Crystal

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Single crystals of Ca3NbGa3Si2O14 (CNGS) with ordered Ca3Ga2Ge4O14 (CGG) structure were successfully grown from stoichiometric melts by conventional Czochralski technique along the a-axis and two large (001) facets and two small (100) facets appear in every crystal. An arrangement of parallel steps and a clear height change were observed in (001) facet by atomic force microscopy (AFM). High-resolution X-ray diffraction (HRXRD) results indicate that CNGS crystals have good quality and free low-angle boundaries. The crystals also exhibit good optical quality and high optical transmittance in c-direction.

  7. Eye retraction in the giant guitarfish, Rhynchobatus djiddensis (Elasmobranchii: Batoidea): a novel mechanism for eye protection in batoid fishes.

    Science.gov (United States)

    Tomita, Taketeru; Murakumo, Kiyomi; Miyamoto, Kei; Sato, Keiichi; Oka, Shin-ichiro; Kamisako, Haruka; Toda, Minoru

    2016-02-01

    Eye retraction behavior has evolved independently in some vertebrate linages such as mudskippers (fish), frogs and salamanders (amphibians), and cetaceans (mammals). In this paper, we report the eye retraction behavior of the giant guitarfish (Rhynchobatus djiddensis) for the first time, and discuss its mechanism and function. The eye retraction distance was nearly the same as the diameter of the eyeball itself, indicating that eye retraction in the giant guitarfish is probably one of the largest among vertebrates. Eye retraction is achieved by unique arrangement of the eye muscle: one of the anterior eye muscles (the obliquus inferior) is directed ventrally from the eyeball and attaches to the ventral surface of the neurocranium. Due to such muscle arrangement, the obliquus inferior can pull the eyeball ventrally. This mechanism was also confirmed by electrical stimulation of the obliquus inferior. The eye retraction ability of the giant guitarfish likely represents a novel eye protection behavior of elasmobranch fishes. PMID:26468088

  8. First principles study of the electronic structure and magnetic properties of spin chain compounds: Ca3ZnMnO6 and Ca3ZnCoO6.

    Science.gov (United States)

    Chakraborty, Jayita; Samanta, Subhasis; Nanda, B R K; Dasgupta, I

    2016-09-21

    We have studied the electronic structure and magnetism of the spin chain compounds Ca3ZnMnO6 and Ca3ZnCoO6 using density functional theory with generalised gradient approximation (GGA). In agreement with experiment our calculations reveal that high spin (HS) state for Mn(4+) ion and low spin (LS) state for Co(4+) ion stabilize the magnetic structure of the respective compounds. The magnetic exchange paths, calculated using Nth order muffin-tin orbital downfolding method, shows dominant intra-chain exchange interaction between the magnetic ions (Mn, Co) is antiferromagnetic for Ca3ZnMnO6 and ferromagnetic for Ca3ZnCoO6. The magnetic order of both the compounds is in accordance with the Goodenough-Kanamori-Anderson rules and is consistent with the experimental results. Finally we have investigated the importance of spin-orbit coupling (SOC) in these compounds. While SOC practically has no effect for the Mn system, it is strong enough to favor the spin quantization along the chain direction for the Co system in the LS state. PMID:27419390

  9. Na4Ca3(AlO2)10:Eu2+,Mn2+荧光粉的发光特性%Photoluminescence Characteristics of Na4 Ca3(AlO2)10:Eu2+ ,Mn2+

    Institute of Scientific and Technical Information of China (English)

    王雪; 田莲花

    2011-01-01

    A novel phosphor Na4Ca3(AlO2) 10:Eu2+ was prepared by solid state reaction method in a thermal-carbon reducing atmosphere. The photoluminescence(PL) properties were investigated in this paper. The excitation spectrum of Na4Ca3(AlO2) 10:Eu2+ showed two absorption bands centered at 262 nm and 320 nm respectively. The photoluminescence spectrum of Na4Ca3(AlO2) 10:Eu2+ exhibited a single emission peak centered at 441 nm, which could be attributed to 5d-4f transition of Eu + . The excitation spectrum of Na4Ca3(AlO2) 10:Eu2+ showed absorption peak at about 440 nm monitoring at 542 nm, which shows spectral overlap between emission spectrum of Na4Ca3(AlO2) 10:Eu2+. Co-doped Mn2+ with Eu2+, the photoluminescence spectra of Na4Ca3(AlO2) 10:Eu2+ were observed two peaks centered at 441 nm and 542 nm corresponding to the 5d-4f transition of Eu2+ and the d-d transition of Mn2+ , respectively. With increasing the concentration of Mn2+ ,the emission intensity of 5d-4f transition of Eu2+ at 441 nm was significantly decreased,whereas the d-d transition of Mn2+ at 542 nm was found to increase. The decay lifetime for Eu2+ was found to decrease with increasing Mn2+ dopant content, which was strong evidence for the energy transfer from Eu2+ to Mn2+ . We were also interested in investigating the energy transfer efficiency ηT of Eu2+→Mn2+ . With increasing Mn2+ dopant content, the energy transfer efficiency ηT was found to increase gradually. According to the Dexter's energy transfer formula of multipolar interaction, it was demonstrated that the energy transfer from Eu2+ to Mn2+ was due to the electric quadripole-quadripole interaction of the resonance transfer. According to the CIE chromaticity coordinates of Na4Ca3(AlO2) 10:Eu2+ , it was clearly observed that the CIE chro-maticity coordinates with the increase of Mn content shifted from blue region to white region.

  10. The Deterministic Dendritic Cell Algorithm

    CERN Document Server

    Greensmith, Julie

    2010-01-01

    The Dendritic Cell Algorithm is an immune-inspired algorithm orig- inally based on the function of natural dendritic cells. The original instantiation of the algorithm is a highly stochastic algorithm. While the performance of the algorithm is good when applied to large real-time datasets, it is difficult to anal- yse due to the number of random-based elements. In this paper a deterministic version of the algorithm is proposed, implemented and tested using a port scan dataset to provide a controllable system. This version consists of a controllable amount of parameters, which are experimented with in this paper. In addition the effects are examined of the use of time windows and variation on the number of cells, both which are shown to influence the algorithm. Finally a novel metric for the assessment of the algorithms output is introduced and proves to be a more sensitive metric than the metric used with the original Dendritic Cell Algorithm.

  11. Evaluation of a novel compule-based gingival retraction system in UK general dental practices.

    Science.gov (United States)

    Burke, F J Trevor; Crisp, Russell John

    2014-06-01

    Twelve members were selected at random from the PREP panel, a group of UK-based dentists who are prepared to carry out research in their practices. A questionnaire was designed to determine the views of the participants, who were asked to use the retraction paste capsules where clinically indicated. They were asked to return the questionnaire after 8 weeks and the information contained therein was collated and presented mainly on visual analogue scales (VAS). A total of 160 impressions were taken using the Astringent Retraction Paste (3M ESPE, Seefeld, Germany) plus use in the placement of 25 restorations. Of evaluators, 83% (n = 10) agreed that Astringent Retraction Paste was a suitable product for gingival retraction and 75% (n = 9) agreed that it had good haemostatic properties. Overall dispensing and handling of the paste was rated as 4.9 on a VAS scale where 1 = Inconvenient and 5 = Convenient. The viscosity of the paste was rated as 3.6 on a VAS where 1 = too thin and 5 = too thick. Good scores were achieved across all criteria for the product. Clinical Relevance: Practitioners may wish to be aware of a novel compule-based gingival retraction system. PMID:25073225

  12. Effect of a cordless retraction paste on titanium surface: a topographic, chemical and biocompatibility evaluation

    Directory of Open Access Journals (Sweden)

    Katherine Cooper

    2013-06-01

    Full Text Available Good exposure of the preparation margins and haemostasis in the sulcular gingiva are necessary for accurate impressions to produce precise restorations. The use of cordless retraction paste material in implant dentistry is a relatively novel application. However, few studies have been conducted on the use of retraction pastes and their possible interaction with implant surfaces. Recent literature has described remnants on titanium implant surfaces and expressed the need for an assessment of the biocompatibility of the exposed surface (Chang et al.. This in vitro study evaluated the effect of a cordless gingival retraction paste on sterile titanium disks. Surface chemistry was determined using energy-dispersive X-ray spectroscopy (EDS, and further investigated using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS. After exposure to retraction paste, surface chemistry alterations were identified. A fibroblast cell line (L929 was exposed to the disks and the live/dead viability/cytotoxicity assay was used to determine any effects on the proliferation and health of cells. The disks exposed to the retraction paste showed fewer dead cells compared to the unexposed disks. This was statistically significant.

  13. The persistence of error: a study of retracted articles on the Internet and in personal libraries*

    Science.gov (United States)

    Davis, Philip M.

    2012-01-01

    Objective: To determine the accessibility of retracted articles residing on non-publisher websites and in personal libraries. Methods: Searches were performed to locate Internet copies of 1,779 retracted articles identified in MEDLINE, published between 1973 and 2010, excluding the publishers' website. Found copies were classified by article version and location. Mendeley (a bibliographic software) was searched for copies residing in personal libraries. Results: Non-publisher websites provided 321 publicly accessible copies for 289 retracted articles: 304 (95%) copies were the publisher' versions, and 13 (4%) were final manuscripts. PubMed Central had 138 (43%) copies; educational websites 94 (29%); commercial websites 24 (7%); advocacy websites 16 (5%); and institutional repositories 10 (3%). Just 15 (5%) full-article views included a retraction statement. Personal Mendeley libraries contained records for 1,340 (75%) retracted articles, shared by 3.4 users, on average. Conclusions: The benefits of decentralized access to scientific articles may come with the cost of promoting incorrect, invalid, or untrustworthy science. Automated methods to deliver status updates to readers may reduce the persistence of error in the scientific literature. PMID:22879807

  14. Effect of a cordless retraction paste on titanium surface: a topographic, chemical and biocompatibility evaluation.

    Science.gov (United States)

    Cooper, Katherine; Bennani, Vincent; Tawse-Smith, Andrew; Reid, Malcolm; Stirling, Claudine; Dias, George

    2013-01-01

    Good exposure of the preparation margins and haemostasis in the sulcular gingiva are necessary for accurate impressions to produce precise restorations. The use of cordless retraction paste material in implant dentistry is a relatively novel application. However, few studies have been conducted on the use of retraction pastes and their possible interaction with implant surfaces. Recent literature has described remnants on titanium implant surfaces and expressed the need for an assessment of the biocompatibility of the exposed surface (Chang et al.). This in vitro study evaluated the effect of a cordless gingival retraction paste on sterile titanium disks. Surface chemistry was determined using energy-dispersive X-ray spectroscopy (EDS), and further investigated using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). After exposure to retraction paste, surface chemistry alterations were identified. A fibroblast cell line (L929) was exposed to the disks and the live/dead viability/cytotoxicity assay was used to determine any effects on the proliferation and health of cells. The disks exposed to the retraction paste showed fewer dead cells compared to the unexposed disks. This was statistically significant. PMID:23739788

  15. Cell-mediated retraction versus hemodynamic loading - A delicate balance in tissue-engineered heart valves.

    Science.gov (United States)

    van Loosdregt, Inge A E W; Argento, Giulia; Driessen-Mol, Anita; Oomens, Cees W J; Baaijens, Frank P T

    2014-06-27

    Preclinical studies of tissue-engineered heart valves (TEHVs) showed retraction of the heart valve leaflets as major failure of function mechanism. This retraction is caused by both passive and active cell stress and passive matrix stress. Cell-mediated retraction induces leaflet shortening that may be counteracted by the hemodynamic loading of the leaflets during diastole. To get insight into this stress balance, the amount and duration of stress generation in engineered heart valve tissue and the stress imposed by physiological hemodynamic loading are quantified via an experimental and a computational approach, respectively. Stress generation by cells was measured using an earlier described in vitro model system, mimicking the culture process of TEHVs. The stress imposed by the blood pressure during diastole on a valve leaflet was determined using finite element modeling. Results show that for both pulmonary and systemic pressure, the stress imposed on the TEHV leaflets is comparable to the stress generated in the leaflets. As the stresses are of similar magnitude, it is likely that the imposed stress cannot counteract the generated stress, in particular when taking into account that hemodynamic loading is only imposed during diastole. This study provides a rational explanation for the retraction found in preclinical studies of TEHVs and represents an important step towards understanding the retraction process seen in TEHVs by a combined experimental and computational approach. PMID:24268314

  16. Performance analysis of the retractable dome for the Chinese Large Telescope.

    Science.gov (United States)

    Nian, Pan; Wen-Li, Ma

    2015-10-01

    In order to quantitatively assess the influence of the retractable dome on the observational performance of the 4-m Chinese Large Telescope (CLT), an integrated analysis method based on computational fluid dynamics (CFD) and sub-harmonic phase screen is proposed in this paper. The pressure, the temperature, and the speed of air surrounding the retractable dome are attained by CFD simulations, and then the fluctuation of refractive index of air is calculated. Based on sub-harmonic phase screen algorithm, three kinds of performance evaluation parameters are presented: irradiance, phase of the target, and Full Width Half Maximum (FWHM). The wind tunnel tests (WT) with a 1:120 scaled model of the retractable dome for the CLT are conducted to verify the calculated precision of the CFD. The results show that the fluctuation of air refractive index surrounding the CLT is mainly caused by the inhomogeneous distribution of temperature and speed, and with the help of pier's height the impact of inhomogeneous air temperature from the ground layer on the fluctuation of air refractive index can be effectively decreased. Furthermore, the lower of the air speed is, the better performance of the retractable dome will be, and when the speed of air is less than 5m/s, the dome seeing induced by the retractable dome on the observational wave front is less than 0.13 arcsec. PMID:26480059

  17. A Miniature Robot for Retraction Tasks under Vision Assistance in Minimally Invasive Surgery

    Directory of Open Access Journals (Sweden)

    Giuseppe Tortora

    2014-03-01

    Full Text Available Minimally Invasive Surgery (MIS is one of the main aims of modern medicine. It enables surgery to be performed with a lower number and severity of incisions. Medical robots have been developed worldwide to offer a robotic alternative to traditional medical procedures. New approaches aimed at a substantial decrease of visible scars have been explored, such as Natural Orifice Transluminal Endoscopic Surgery (NOTES. Simple surgical tasks such as the retraction of an organ can be a challenge when performed from narrow access ports. For this reason, there is a continuous need to develop new robotic tools for performing dedicated tasks. This article illustrates the design and testing of a new robotic tool for retraction tasks under vision assistance for NOTES. The retraction robots integrate brushless motors to enable additional degrees of freedom to that provided by magnetic anchoring, thus improving the dexterity of the overall platform. The retraction robot can be easily controlled to reach the target organ and apply a retraction force of up to 1.53 N. Additional degrees of freedom can be used for smooth manipulation and grasping of the organ.

  18. Breast Retraction Assessment: an objective evaluation of cosmetic results of patients treated conservatively for breast cancer

    International Nuclear Information System (INIS)

    Breast Retraction Assessment (BRA) is an objective evaluation of the amount of cosmetic retraction of the treated breast in comparison to the untreated breast in patients who receive conservative treatment for breast cancer. A clear acrylic sheet supported vertically and marked as a grid at 1 cm intervals is employed to perform the measurements. Average BRA value in 29 control patients without breast cancer was 1.2 cm. Average BRA value in 27 patients treated conservatively for clinical Stage I or II unilateral breast cancer was 3.7 cm. BRA values in breast cancer patients ranged from 0.0 to 8.5 cm. Patients who received a local radiation boost to the primary tumor bed site had statistically significantly less retraction than those who did not receive a boost. Patients who had an extensive primary tumor resection had statistically significantly more retraction than those who underwent a more limited resection. In comparison to qualitative forms of cosmetic analysis, BRA is an objective test that can quantitatively evaluate factors which may be related to cosmetic retraction in patients treated conservatively for breast cancer

  19. Memory effect in spin-chain single crystal Ca3Co1.62Mn0.38O6

    International Nuclear Information System (INIS)

    Highlights: • The memory effect exists in the spin-chain single crystal Ca3Co1.62Mn0.38O6. • The memory effect in Ca3Co1.62Mn0.38O6 is associated with chemical disorder and competing interactions. • The observed memory effect can be described by the phenomenological hierarchical model. - Abstract: Amazing memory effect due to spin glass-like freezing has been illustrated in the spin-chain single crystal of Ca3Co1.62Mn0.38O6 by systematic magnetization measurements including temperature- and time-dependent magnetization curves in low fields. The observed memory effect can be described by the phenomenological hierarchical model and its origin is associated with chemical disorder and competing antiferromagnetic and ferromagnetic interactions due to introduction of Mn. Thus, Ca3Co1.62Mn0.38O6 may be considered as a candidate material for the memory storage devices

  20. Effects of Synthesis and Processing on the Thermoelectric Properties of Ca3Co4O9+δ

    DEFF Research Database (Denmark)

    Wu, NingYu; Holgate, Tim; Van Nong, Ngo;

    In the present study, Ca3Co4O9+δ was synthesized by solid-state and sol-gel reactions followed by spark plasma sintering (SPS) under different conditions such as sintering temperatures, applied pressures and ramping rates. The materials were then characterized with respect to their microstructure...

  1. The antidepressant tianeptine persistently modulates glutamate receptor currents of the hippocampal CA3 commissural associational synapse in chronically stressed rats

    NARCIS (Netherlands)

    Kole, MHP; Swan, L; Fuchs, E

    2002-01-01

    Recent hypotheses on the action of antidepressants imply a modulation of excitatory amino acid transmission. Here, the effects of long-term antidepressant application in rats with the drug tianeptine were examined at hippocampal CA3 commissural associational (c/a) glutamate receptor ion channels, em

  2. Evidence of the Current Collector Effect: Study of the SOFC Cathode Material Ca3Co4O9+d

    NARCIS (Netherlands)

    Rolle, A.; Thoréton, V.; Rozier, P.; Capoen, E.; Mentré, O.; Boukamp, B.A.; Daviero-Minaud, S.

    2012-01-01

    In the study of the performance of solid oxide fuel cell (SOFC) electrodes, the possible influence of the applied current collector is often not mentioned or recognized. In this article, as part of an optimization study of the potentially attractive Ca3Co4O9+δ cathode material (Ca349), special atten

  3. An inverse approach for elucidating dendritic function

    Directory of Open Access Journals (Sweden)

    Benjamin Torben-Nielsen

    2010-09-01

    Full Text Available We outline an inverse approach for investigating dendritic function-structure relationships by optimizing dendritic trees for a-priori chosen computational functions. The inverse approach can be applied in two different ways. First, we can use it as a `hypothesis generator' in which we optimize dendrites for a function of general interest. The optimization yields an artificial dendrite that is subsequently compared to real neurons. This comparison potentially allows us to propose hypotheses about the function of real neurons. In this way, we investigated dendrites that optimally perform input-order detection. Second, we can use it as a `function confirmation' by optimizing dendrites for functions hypothesized to be performed by classes of neurons. If the optimized, artificial, dendrites resemble the dendrites of real neurons the artificial dendrites corroborate the hypothesized function of the real neuron. Moreover, properties of the artificial dendrites can lead to predictions about yet unmeasured properties. In this way, we investigated wide-field motion integration performed by the VS cells of the fly visual system. In outlining the inverse approach and two applications, we also elaborate on the nature of dendritic function. We furthermore discuss the role of optimality in assigning functions to dendrites and point out interesting future directions.

  4. Mechanical and thermal-expansion characteristics of Ca10(PO46(OH2-Ca3(PO42 composites

    Directory of Open Access Journals (Sweden)

    Ruseska G.

    2006-01-01

    Full Text Available Three types of composites consisting of Ca10(PO46(OH2 and Ca3(PO42 with composition: 75% (wt Ca10(PO46(OH2: 25%(wt Ca3(PO42; 50%(wt Ca10(PO46(OH2: 50%(wtCa3(PO42 and 25 %(wt Ca10(PO46(OH2: 75%(wt Ca3(PO42 were the subject of our investigation. Sintered compacts were in thermal equilibrium, which was proved by the absence of hysteresis effect of the dependence ΔL/L=f(T during heating /cooling in the temperature interval 20-1000-200C. Sintered compacts with the previously mentioned composition possess 26-50% higher values of the E-modulus, G-modulus and K-modulus indicating the presence of a synergism effect. Several proposed model equations for predicting the thermal expansion coefficient in dependence of the thermal and elastic properties of the constitutive phases and their volume fractions, given by: Turner, Kerner, Tummala and Friedberg, Thomas and Taya, were used for making correlations between mechanical and thermal-expansion characteristics of the Ca10(PO46(OH2 - Ca3(PO42 composites. Application of the previously mentioned model equations to all kinds of composites leads to the conclusion that the experimentally obtained results for the thermal expansion coefficient are in an excellent agreement with the theoretical calculated values on account of the volume fraction of each constitutive phase and with all applied model equations, with a coefficient of correlation from 98.16-99.86 %.

  5. α-FUZZY PAIRWISE RETRACT OF L-VALUED PAIRWISE STRATIFICATION SPACES

    Institute of Scientific and Technical Information of China (English)

    M. H. GHANIM; F. S. MAHMOUD; M. A. FATH ALLA; M.A. HEBESHI

    2004-01-01

    The notion of a fuzzy retract was introduced by Rodabaugh (1981). The notion of a fuzzy pairwise retract was introduced in 2001. Some weak forms and some strong forms of α-continuous mappings were introduced in 1988 and 1997. The authors extend some of these forms to the L-fuzzy bitopological setting and construct various α-fuzzy pairwise retracts. The concept of weakly induced spaces in the case L = [0, 1] was introduced by Martin (1980). Lin and Luo (1987) generalized this notion to the case that L is an arbitrary F-lattice and introduced the notion of induced L-fts. Several results are obtained, especially, for L-valued pairwise stratification spaces.

  6. RETRACTED: Influence of temperature and microstructure on the mechanical properties of sintered nanosilver joints

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Gang; Wang, Yi-Zhe [School of Chemical Engineering and Technology, Tianjin University, Tianjin (China); Mei, Yunhui, E-mail: yunhui@tju.edu.cn [Tianjin Key Laboratory of Advanced Joining Technology, Tianjin University, Tianjin (China); School of Material Science and Engineering, Tianjin University, Tianjin (China); Yu, Lin [School of Chemical Engineering and Technology, Tianjin University, Tianjin (China); Li, Xin [Tianjin Key Laboratory of Advanced Joining Technology, Tianjin University, Tianjin (China); School of Material Science and Engineering, Tianjin University, Tianjin (China); Chen, Xu [School of Chemical Engineering and Technology, Tianjin University, Tianjin (China)

    2015-02-25

    This article has been retracted: please see Elsevier Policy on Article Withdrawal ( (http://www.elsevier.com/locate/withdrawalpolicy)). This article has been retracted at the request of the Editor-in-Chief. Please note that the reason for this retraction has been updated in July 2015, as follows: The authors have plagiarized part of a paper that had already appeared in 'Electronic System-Integration Technology Conference (ESTC), 2010 3rd', 1-6, (101109/ESTC.2010.5642948). One of the conditions of submission of a paper for publication is that authors declare explicitly that their work is original and that no substantial portion has appeared in a publication elsewhere. As such this article represents an abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process.

  7. RETRACTED: Influence of temperature and microstructure on the mechanical properties of sintered nanosilver joints

    International Nuclear Information System (INIS)

    This article has been retracted: please see Elsevier Policy on Article Withdrawal ( (http://www.elsevier.com/locate/withdrawalpolicy)). This article has been retracted at the request of the Editor-in-Chief. Please note that the reason for this retraction has been updated in July 2015, as follows: The authors have plagiarized part of a paper that had already appeared in 'Electronic System-Integration Technology Conference (ESTC), 2010 3rd', 1-6, (101109/ESTC.2010.5642948). One of the conditions of submission of a paper for publication is that authors declare explicitly that their work is original and that no substantial portion has appeared in a publication elsewhere. As such this article represents an abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process

  8. Intrinsic and extrinsic mechanisms of dendritic morphogenesis.

    Science.gov (United States)

    Dong, Xintong; Shen, Kang; Bülow, Hannes E

    2015-01-01

    The complex, branched morphology of dendrites is a cardinal feature of neurons and has been used as a criterion for cell type identification since the beginning of neurobiology. Regulated dendritic outgrowth and branching during development form the basis of receptive fields for neurons and are essential for the wiring of the nervous system. The cellular and molecular mechanisms of dendritic morphogenesis have been an intensely studied area. In this review, we summarize the major experimental systems that have contributed to our understandings of dendritic development as well as the intrinsic and extrinsic mechanisms that instruct the neurons to form cell type-specific dendritic arbors. PMID:25386991

  9. Monocyte-derived dendritic cells

    OpenAIRE

    Kuhn, Sabine; Ronchese, Franca

    2013-01-01

    The elicitation of efficient antitumor immune responses requires the optimal activation of tumor-associated dendritic cells (DCs). Our comparison of the effect of various immunostimulatory treatments on DCs revealed that the best predictor of the success of immunotherapy is not the activation of existing DC populations, but the appearance of a population of monocyte-derived DC in tumor-draining lymph nodes.

  10. Fast generation of dendritic cells

    DEFF Research Database (Denmark)

    Kvistborg, P; Bøgh, Marie; Claesson, M H; Pedersen, A W

    2009-01-01

    Dendritic cells (DC) are potent antigen presenting cells capable of inducing immune responses. DC are widely used as vaccine adjuvant in experimental clinical settings. DC-based vaccines are normally generated using a standard 8day DC protocol (SDDC). In attempts to shorten the vaccine production...

  11. Retraction note: The prevalence of obstructive sleep apnea in patients with difficult-to-treat asthma.

    Science.gov (United States)

    2015-12-01

    This original article, published in the Asian Pacific Journal of Allergy and Immunology, has been retracted from this journal based on an error in the analysis included a patient who has not given informed consent. The authors could not be contacted to provide the explanation. Due to the nature of the error, the Editor-in-Chief and the Associate Editors have decided to retract this article although this error does not affect the validity of the study. We apologize for any adverse consequences this may have caused. PMID:26708400

  12. RETRACTED: A novel membrane-based anti-diabetic action of atorvastatin

    International Nuclear Information System (INIS)

    This article has been retracted. Please see Elsevier Policy on Article Withdrawal ((http://www.elsevier.com/locate/withdrawalpolicy)). Reason: The editors would like to confirm the retraction of this paper at the request of the authors. One of the authors, Emily M. Horvath, admitted to altering data in two of the figures. Specifically in Figures 2, and 4A, some of the values were incorrectly reported for the radioactive glucose uptake assays. None of the other authors associated with this publication were aware of the data manipulation. The authors sincerely regret if this has caused problems with investigators that have used this information experimentally.

  13. RETRACTED: A novel membrane-based anti-diabetic action of atorvastatin

    Energy Technology Data Exchange (ETDEWEB)

    Horvath, Emily M.; Tackett, Lixuan [Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Center for Diabetes Research, VanNuys Medical Science, Building Rm 308A, Indianapolis, IN 46202 (United States); Elmendorf, Jeffrey S., E-mail: jelmendo@iupui.edu [Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Center for Diabetes Research, VanNuys Medical Science, Building Rm 308A, Indianapolis, IN 46202 (United States); Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Center for Diabetes Research, Indianapolis, IN 46202 (United States)

    2008-08-08

    This article has been retracted. Please see Elsevier Policy on Article Withdrawal ((http://www.elsevier.com/locate/withdrawalpolicy)). Reason: The editors would like to confirm the retraction of this paper at the request of the authors. One of the authors, Emily M. Horvath, admitted to altering data in two of the figures. Specifically in Figures 2, and 4A, some of the values were incorrectly reported for the radioactive glucose uptake assays. None of the other authors associated with this publication were aware of the data manipulation. The authors sincerely regret if this has caused problems with investigators that have used this information experimentally.

  14. RETRACTED: Translating Connotative Meaning in Literary Texts at the University of Petra

    Directory of Open Access Journals (Sweden)

    Akram M. Beiruti

    2013-09-01

    Full Text Available This article has been retracted: please see AIAC PTY.LTD. Policy on Publication Ethics and Publication Malpractice Statement.(http://www.aiac.org.au/journals/Subtemps/PEPMS.pdfThis article has been retracted based on the editorial decision upon conducting a thorough invesitigatiosn. It came to our notice that Akram Beirtui, supposedly the author of this paper, has plagirised the entire paper from an unpublished paper conducted by Ahmad Al-Hassan, who is the main author of the paper from the same university. Upon his proof to us, we reserve his rights and removed the paper.  

  15. Retracted article: Flexible Fourier Stationary Test in GDP per capita for Central Eastern European Countries

    OpenAIRE

    Chi-Wei Su; Meng-Nan Zhu; Hsu-Ling Chang

    2011-01-01

    Statement of Retraction (http://www.efri.uniri.hr/prikaz.asp?txt_id=7366) This is to notify our respectful reading public that the Editorial Board of the journal Zbornik radova Ekonomskog fakulteta u Rijeci, časopis za ekonomsku teoriju i praksu/ Proceedings of Rijeka Faculty of Economics, Journal of Economics and Business has retracted the following article from publication: “Flexible Fourier Stationary Test in GDP per capita for Central Eastern European Countries“, by Hsu-Ling Chang, Chi-We...

  16. Calculatoin and experimental study of the retracting force for magnetic spring of two types

    CERN Document Server

    Tsivilitsin, V; Goncharuk, V; Bondar, I

    2014-01-01

    Designs for magnetic springs of two types have been proposed, and the methods of calculation of their retracting forces have been developed. Formulas are obtained for the retracting force in the main section of spring force characteristics. Experimental data are in good agreement with the results of theoretical calculations. The force characteristics of the proposed magnetic spring constructions can be varied for a specific application. The derived formulas are verified experimentally. Ways to change the force characteristics of magnetic springs according to specific requirements are demonstrated.

  17. Traction force microscopy in rapidly moving cells reveals separate roles for ROCK and MLCK in the mechanics of retraction.

    Science.gov (United States)

    Morin, Timothy R; Ghassem-Zadeh, Sean A; Lee, Juliet

    2014-08-15

    Retraction is a major rate-limiting step in cell motility, particularly in slow moving cell types that form large stable adhesions. Myosin II dependent contractile forces are thought to facilitate detachment by physically pulling up the rear edge. However, retraction can occur in the absence of myosin II activity in cell types that form small labile adhesions. To investigate the role of contractile force generation in retraction, we performed traction force microscopy during the movement of fish epithelial keratocytes. By correlating changes in local traction stress at the rear with the area retracted, we identified four distinct modes of retraction. "Recoil" retractions are preceded by a rise in local traction stress, while rear edge is temporarily stuck, followed by a sharp drop in traction stress upon detachment. This retraction type was most common in cells generating high average traction stress. In "pull" type retractions local traction stress and area retracted increase concomitantly. This was the predominant type of retraction in keratocytes and was observed mostly in cells generating low average traction stress. "Continuous" type retractions occur without any detectable change in traction stress, and are seen in cells generating low average traction stress. In contrast, to many other cell types, "release" type retractions occur in keratocytes following a decrease in local traction stress. Our identification of distinct modes of retraction suggests that contractile forces may play different roles in detachment that are related to rear adhesion strength. To determine how the regulation of contractility via MLCK or Rho kinase contributes to the mechanics of detachment, inhibitors were used to block or augment these pathways. Modulation of MLCK activity led to the most rapid change in local traction stress suggesting its importance in regulating attachment strength. Surprisingly, Rho kinase was not required for detachment, but was essential for localizing

  18. Growth and polarized spectral properties of Sm3+ doped in Ca3La2(BO3)4 crystal

    Science.gov (United States)

    Wang, Yeqing; Chen, Aixi; Tu, Chaoyang

    2015-09-01

    A Sm3+-doped Ca3La2(BO3)4 single crystal was grown by the Czochralski method. Its polarized absorption, emission spectra and fluorescence lifetime measurements were carried out at room temperature. Based on the Judd-Ofelt theory, the spectroscopic parameters Ωt (t = 2, 4, 6), radiative transition probabilities, radiative lifetime and fluorescence branching ratios were obtained. The stimulated emission cross section, the fluorescence lifetime and the quantum efficiency of the promising laser transition were also calculated and compared with other reported crystals. The results showed that Sm3+:Ca3La2(BO3)4 is a promising candidate for the orange-yellow laser emission.

  19. Electron radiation damages to dicalcium (Ca2SiO4) and tricalcium (Ca3SiO5) orthosilicates

    Science.gov (United States)

    de Noirfontaine, Marie-Noëlle; Dunstetter, Frédéric; Courtial, Mireille; Signes-Frehel, Marcel; Wang, Guillaume; Gorse-Pomonti, Dominique

    2016-05-01

    Electron radiation damages to dicalcium silicate (Ca2SiO4) and tricalcium silicate (Ca3SiO5) are reported for the first time in this paper. With increasing flux, between 2.7 × 1017 and 2.2 × 1022 e- cm-2 s-1, decomposition into nanodomains of crystalline CaO plus an amorphous silica rich phase is first observed for both silicates, then amorphization at higher flux always for both silicates, and finally hole drilling but only for Ca3SiO5. These structural modifications are accompanied by a net reduction of Ca content under the electron beam depending on the silicate species. These radiation effects occur for values of flux and dose larger than in previously studied orthosilicates (like olivines), and much larger than in all tectosilicates.

  20. TOWARDS HIGHLY EFFICIENT THERMOELECTRICS: Ca3Co4O9+δ . n CaZrO3 COMPOSITE

    OpenAIRE

    Ondrej Jankovsky; Stepan Huber; Sedmidubsky David; Nadherny Ladislav; Hlasek Tomas; Sofer Zdenek

    2014-01-01

    We successfully prepared Ca3Co4O9+δ . n CaZrO3 composites by a ceramic route. These composites were characterized by X-Ray diffraction, differential thermal analysis, thermogravimetric analysis and scanning electron microscopy. Moreover, transport properties (Seebeck coefficient, electrical resistivity and thermal conductivity) were measured and the thermoelectric figure of merit ZT was determined. Addition of CaZrO3 led to a suppression of thermal conductivity of the samples. A high...

  1. Increased size and stability of CA1 and CA3 place fields in HCN1 knockout mice

    OpenAIRE

    Hussaini, Syed A.; Kempadoo, Kimberly A.; Thuault, Sébastien J.; Siegelbaum, Steven A.; Kandel, Eric R.

    2011-01-01

    Hippocampal CA1 and CA3 pyramidal neuron place cells encode the spatial location of an animal through localized firing patterns called “place fields”. To explore the mechanisms that control place cell firing and their relationship to spatial memory, we studied mice with enhanced spatial memory resulting from forebrain-specific knockout of the HCN1 hyperpolarization-activated cation channel. HCN1 is strongly expressed in CA1 neurons and entorhinal cortex grid cells, which provide spatial infor...

  2. Growth of Devitrite, Na2Ca3Si6O16, in Soda-Lime-Silica Glass

    OpenAIRE

    Knowles, Kevin M.; Thompson, Robert P.

    2014-01-01

    This article (Knowles, K. M., Thompson, R. P. (2014), Growth of Devitrite, Na2Ca3Si6O16, in Soda?Lime?Silica Glass. Journal of the American Ceramic Society, 97: 1425?1433. doi: 10.1111/jace.12922) is the author accepted manuscript, which can also be found on the publisher's website at: http://onlinelibrary.wiley.com/doi/10.1111/jace.12922/abstract ? 2014 The American Ceramic Society

  3. Human neuroimaging studies on the hippocampal CA3 region – integrating evidence for pattern separation and completion

    Directory of Open Access Journals (Sweden)

    Lorena eDeuker

    2014-03-01

    Full Text Available Human functional magnetic imaging (fMRI studies have long investigated the hippocampus without differentiating between its subfields, even though theoretical models and rodent studies suggest that subfields support different and potentially even opposite functions. The CA3 region of the hippocampus has been ascribed a pivotal role both in initially forming associations during encoding and in reconstructing a memory representation based on partial cues during retrieval. These functions have been related to pattern separation and pattern completion, respectively. In recent years, studies using high-resolution fMRI in humans have begun to separate different hippocampal subregions and identify the role of the CA3 subregion relative to the other subregions. However, some of these findings have been inconsistent with theoretical models and findings from electrophysiology. In this review, we describe selected recent studies and highlight how their results might help to define different processes and functions that are presumably carried out by the CA3 region, in particular regarding the seemingly opposing functions of pattern separation and pattern completion. We also describe how these subfield-specific processes are related to behavioral, functional and structural alterations in patients with mild cognitive impairment and Alzheimer’s disease. We conclude with discussing limitations of functional imaging and briefly outline possible future developments of the field.

  4. Spin frustration and magnetic ordering in triangular lattice antiferromagnet Ca3CoNb2O9

    Science.gov (United States)

    Dai, Jia; Zhou, Ping; Wang, Peng-Shuai; Pang, Fei; Munsie, Tim J.; Luke, Graeme M.; Zhang, Jin-Shan; Yu, Wei-Qiang

    2015-12-01

    We synthesized a quasi-two-dimensional distorted triangular lattice antiferromagnet Ca3CoNb2O9, in which the effective spin of Co2+ is 1/2 at low temperatures, whose magnetic properties were studied by dc susceptibility and magnetization techniques. The x-ray diffraction confirms the quality of our powder samples. The large Weiss constant θCW˜ -55 K and the low Neel temperature TN˜ 1.45 K give a frustration factor f = | θCW/TN | ≈ 38, suggesting that Ca3CoNb2O9 resides in strong frustration regime. Slightly below TN, deviation between the susceptibility data under zero-field cooling (ZFC) and field cooling (FC) is observed. A new magnetic state with 1/3 of the saturate magnetization Ms is suggested in the magnetization curve at 0.46 K. Our study indicates that Ca3CoNb2O9 is an interesting material to investigate magnetism in triangular lattice antiferromagnets with weak anisotropy. Project supported by the National Natural Science Foundation of China (Grant Nos. 11374364 and 11222433), the National Basic Research Program of China (Grant No. 2011CBA00112). Research at McMaster University supported by the Natural Sciences and Engineering Research Council. Work at North China Electric Power University supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry.

  5. Corticosterone rapidly increases thorns of CA3 neurons via synaptic/extranuclear glucocorticoid receptor in rat hippocampus

    Directory of Open Access Journals (Sweden)

    Miyuki Yoshiya

    2013-11-01

    We demonstrated rapid effects (~ 1 h of CORT on the density of thorns, by imaging Lucifer Yellow-injected neurons in adult male rat hippocampal slices. Thorns of thorny excrescences of CA3 hippocampal neurons are post-synaptic regions whose presynaptic partners are mossy fiber terminals. The application of CORT at 100, 500 and 1000 nM induced a rapid increase in the density of thorns in the stratum lucidum of CA3 pyramidal neurons. Co-administration of RU486, an antagonist of glucocorticoid receptor (GR, abolished the effect of CORT. Blocking a single kinase, including MAPK, PKA or PKC, suppressed CORT-induced enhancement of thorn-genesis. On the other hand, GSK-3β was not involved in the signaling of thorn-genesis. Blocking AMPA receptors suppressed the CORT effect. Expression of CA3 synaptic/extranuclear GR was demonstrated by immunogold electron microscopic analysis. From these results, stress levels of CORT (100-1000 nM might drive the rapid thorn-genesis via synaptic/extranuclear GR and multiple kinase pathways, although a role of nuclear GRs cannot be completely excluded.

  6. Microtubule nucleation and organization in dendrites.

    Science.gov (United States)

    Delandre, Caroline; Amikura, Reiko; Moore, Adrian W

    2016-07-01

    Dendrite branching is an essential process for building complex nervous systems. It determines the number, distribution and integration of inputs into a neuron, and is regulated to create the diverse dendrite arbor branching patterns characteristic of different neuron types. The microtubule cytoskeleton is critical to provide structure and exert force during dendrite branching. It also supports the functional requirements of dendrites, reflected by differential microtubule architectural organization between neuron types, illustrated here for sensory neurons. Both anterograde and retrograde microtubule polymerization occur within growing dendrites, and recent studies indicate that branching is enhanced by anterograde microtubule polymerization events in nascent branches. The polarities of microtubule polymerization events are regulated by the position and orientation of microtubule nucleation events in the dendrite arbor. Golgi outposts are a primary microtubule nucleation center in dendrites and share common nucleation machinery with the centrosome. In addition, pre-existing dendrite microtubules may act as nucleation sites. We discuss how balancing the activities of distinct nucleation machineries within the growing dendrite can alter microtubule polymerization polarity and dendrite branching, and how regulating this balance can generate neuron type-specific morphologies. PMID:27097122

  7. Effectiveness of Mini Implants in Three-Dimensional Control During Retraction - A Clinical Study

    OpenAIRE

    Victor, Deepak; Prabhakar, Ramchandra; Karthikeyan, M.K.; R.Saravanan; Vanathi, P.; Vikram, N. Raj; Reddy, P. Adarsh; Sudeepthi, M.

    2013-01-01

    Introduction: Three-dimensional control throughout the orthodontic treatment is essential for uncompromised results. Mini screws introduced for orthodontic anchorage has given the clinician an option of absolute three dimensional control. The purpose of this study was to compare and measure the vertical control and torque control of incisors and molar during enmass retraction with titanium microimplants and conventional molar anchorage.

  8. Retraction of an intrathecal baclofen infusion catheter following suprapubic cystotomy: a case report.

    NARCIS (Netherlands)

    Martens, F.M.J.; Somford, D.M.; Kuppevelt, D.H. van; Burg, M.J. van den; Heesakkers, J.P.F.A.

    2009-01-01

    INTRODUCTION: Intrathecal baclofen, administered via a Baclofen pump, is used for patients with spasticity. We report here a case of intrathecal catheter retraction following surgery. CASE REPORT: A male patient with adrenoleukodystrophy and a baclofen pump implant was admitted to the urology depart

  9. 77 FR 75189 - Certain Electronic Devices Having a Retractable USB Connector; Termination of an Investigation

    Science.gov (United States)

    2012-12-19

    .... 77 FR 31039-40 (Aug. 12, 2011). The notice of investigation named more than forty respondents. The... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Certain Electronic Devices Having a Retractable USB Connector; Termination of an...

  10. Serbo-Croatian accent retraction : its course and character in the dialect of Dubrovnik

    NARCIS (Netherlands)

    Ligorio, Orsat

    2016-01-01

    Serbo-Croatian Accent Retraction: Its Course and Character in the Dialect of Dubrovnik investigates the evolution of the place of stress in the history of Serbo-Croatian accentuation. The dialect of Dubrovnik, which belongs to the Neoštokavian dialect group, is characterised, like the Serbo-Croatia

  11. Phase field modeling of dendritic coarsening during isothermal

    Directory of Open Access Journals (Sweden)

    Zhang Yutuo

    2011-08-01

    Full Text Available Dendritic coarsening in Al-2mol%Si alloy during isothermal solidification at 880K was investigated by phase field modeling. Three coarsening mechanisms operate in the alloy: (a melting of small dendrite arms; (b coalescence of dendrites near the tips leading to the entrapment of liquid droplets; (c smoothing of dendrites. Dendrite melting is found to be dominant in the stage of dendritic growth, whereas coalescence of dendrites and smoothing of dendrites are dominant during isothermal holding. The simulated results provide a better understanding of dendrite coarsening during isothermal solidification.

  12. K(Ca3.1 channel-blockade attenuates airway pathophysiology in a sheep model of chronic asthma.

    Directory of Open Access Journals (Sweden)

    Joanne Van Der Velden

    Full Text Available BACKGROUND: The Ca(2+-activated K(+ channel K(Ca3.1 is expressed in several structural and inflammatory airway cell types and is proposed to play an important role in the pathophysiology of asthma. The aim of the current study was to determine whether inhibition of K(Ca3.1 modifies experimental asthma in sheep. METHODOLOGY AND PRINCIPAL FINDINGS: Atopic sheep were administered either 30 mg/kg Senicapoc (ICA-17073, a selective inhibitor of the K(Ca3.1-channel, or vehicle alone (0.5% methylcellulose twice daily (orally. Both groups received fortnightly aerosol challenges with house dust mite allergen for fourteen weeks. A separate sheep group received no allergen challenges or drug treatment. In the vehicle-control group, twelve weeks of allergen challenges resulted in a 60±19% increase in resting airway resistance, and this was completely attenuated by treatment with Senicapoc (0.25±12%; n = 10, P = 0.0147. The vehicle-control group had a peak-early phase increase in lung resistance of 82±21%, and this was reduced by 58% with Senicapoc treatment (24±14%; n = 10, P = 0.0288. Senicapoc-treated sheep also demonstrated reduced airway hyperresponsiveness, requiring a significantly higher dose of carbachol to increase resistance by 100% compared to allergen-challenged vehicle-control sheep (20±5 vs. 52±18 breath-units of carbachol; n = 10, P = 0.0340. Senicapoc also significantly reduced eosinophil numbers in bronchoalveolar lavage taken 48 hours post-allergen challenge, and reduced vascular remodelling. CONCLUSIONS: These findings suggest that K(Ca3.1-activity contributes to allergen-induced airway responses, inflammation and vascular remodelling in a sheep model of asthma, and that inhibition of K(Ca3.1 may be an effective strategy for blocking allergen-induced airway inflammation and hyperresponsiveness in humans.

  13. Effects of inhaled anesthetic isoflurane on long-term potentiation of CA3 pyramidal cell afferents in vivo

    Directory of Open Access Journals (Sweden)

    Ballesteros KA

    2012-11-01

    Full Text Available Kristen A Ballesteros,1 Angela Sikorski,2 James E Orfila,3 Joe L Martinez Jr41Department of Biology, The University of Texas at San Antonio, San Antonio, TX, USA; 2Texas A&M University Texarkana, Texarkana, TX, USA; 3University of Colorado in Denver, Denver, CO, USA; 4University of Illinois in Chicago, Chicago, IL, USAAbstract: Isoflurane is a preferred anesthetic, due to its properties that allow a precise concentration to be delivered continually during in vivo experimentation. The major mechanism of action of isoflurane is modulation of the γ-amino butyric acid (GABAA receptor-chloride channel, mediating inhibitory synaptic transmission. Animal studies have shown that isoflurane does not cause cell death, but it does inhibit cell growth and causes long-term hippocampal learning deficits. As there are no studies characterizing the effects of isoflurane on electrophysiological aspects of long-term potentiation (LTP in the hippocampus, it is important to determine whether isoflurane alters the characteristic responses of hippocampal afferents to cornu ammonis region 3 (CA3. We investigated the effects of isoflurane on adult male rats during in vivo induction of LTP, using the mossy fiber pathway, the lateral perforant pathway, the medial perforant pathway, and the commissural CA3 (cCA3 to CA3, with intracranial administration of Ringer’s solution, naloxone, RS-aminoindan-1, 5-dicarboxylic acid (AIDA, or 3-[(R-2-carboxypiperazin-4-yl]-propo-2-enyl-1-phosphonic acid (CPP. Then, we compared these responses to published electrophysiological data, using sodium pentobarbital as an anesthetic, under similar experimental conditions. Our results showed that LTP was exhibited in animals anesthetized with isoflurane under vehicle conditions. With the exception of AIDA in the lateral perforant pathway, the defining characteristics of the four pathways appeared to remain intact, except for the observation that LTP was markedly reduced in animals

  14. Drosophila Sensory Neurons Require Dscam for Dendritic Self Avoidance and Proper Dendritic Field Organization

    OpenAIRE

    Soba, Peter; Zhu, Sijun; Emoto, Kazuo; Younger, Susan; Yang, Shun-Jen; Yu, Hung-Hsiang; Lee, Tzumin; Jan, Lily Yeh; Jan, Yuh-Nung

    2007-01-01

    A neuron’s dendrites typically do not cross one another. This intrinsic self-avoidance mechanism ensures unambiguous processing of sensory or synaptic inputs. Moreover, some neurons respect the territory of others of the same type, a phenomenon known as tiling. Different types of neurons, however, often have overlapping dendritic fields. We found that Down’s syndrome Cell Adhesion Molecule (Dscam) is required for dendritic self-avoidance of all four classes of Drosophila dendritic arborizatio...

  15. Homophilic Dscam interactions control complex dendrite morphogenesis

    OpenAIRE

    Michael E Hughes; Bortnick, Rachel; Tsubouchi, Asako; Bäumer, Philipp; Kondo, Masahiro; Uemura, Tadashi; Schmucker, Dietmar

    2007-01-01

    The morphogenesis of complex dendritic fields requires highly specific patterning and dendrite-dendrite recognition mechanisms. Alternative splicing of the Drosophila cell surface receptor Dscam results in up to 38,016 different receptor isoforms and in vitro binding studies suggested that sequence variability in immunoglobulin-like ecto-domains determines the specificity of strictly homophilic interactions. We report that diverse Dscam receptors play an important role in controlling cell-int...

  16. Precipitation dendrites in turbulent pipe flows

    Science.gov (United States)

    Angheluta, Luiza; Hawkins, Christopher; Hammer, Øyvind; Jamtveit, Bjørn

    2013-04-01

    Surface precipitation in pipelines, as well as freezing in water pipes is of great concern in many industrial applications where scaling phenomena becomes a control problem of pipe-clogging or an efficiency reduction in transport. Flow blockage often occurs even when only a small fraction is deposited non-uniformly on the walls in the form of dendrites. Dendritic patterns are commonly encountered in surface precipitation from supersaturated solutions, e.g. calcite dendrites, as well as in solidification from undercooled liquids, e.g. freezing of water into ice dendrites. We explore the mathematical similarities between precipitation and freezing processes and, in particular, investigate the effect of fluid flow on the precipitation dendrites on pipe walls. We use a phase field approach to model surface growth coupled with a lattice Boltzmann method that simulates a channel flow at varying Reynolds number. The dendrites orientation and shape depend non-trivially on the ratio between advection and diffusion, i.e. the Peclet number, as well as the Reynolds number. Roughness induced vortices near growing dendrites at high flow rates further affect the branch splitting of dendrites. We show how the transport rate in a pipeline may depend on the different dendritic morphologies, and provide estimates for the flow conditions that correspond to most efficient transport regimes.

  17. Hierarchical assembly of diphenylalanine into dendritic nanoarchitectures.

    Science.gov (United States)

    Han, Tae Hee; Oh, Jun Kyun; Lee, Gyoung-Ja; Pyun, Su-Il; Kim, Sang Ouk

    2010-09-01

    Highly ordered, multi-dimensional dendritic nanoarchitectures were created via self-assembly of diphenylalanine from an acidic buffer solution. The self-similarity of dendritic structures was characterized by examining their fractal dimensions with the box-counting method. The fractal dimension was determined to be 1.7, which demonstrates the fractal dimension of structures generated by diffusion limited aggregation on a two-dimensional substrate surface. By confining the dendritic assembly of diphenylalanine within PDMS microchannels, the self-similar dendritic growth could be hierarchically directed to create linearly assembled nanoarchitectures. Our approach offers a novel pathway for creating and directing hierarchical nanoarchitecture from biomolecular assembly. PMID:20605423

  18. Clinical study of gingival retraction time on the effect of gingival retraction%排龈时间对排龈效果影响的临床研究

    Institute of Scientific and Technical Information of China (English)

    张津京; 刘玉华

    2011-01-01

    目的 比较三种排龈时间下的排龈效果,为临床上排龈时间的选择提供参考.方法 选取10名志愿者的59颗前磨牙或尖牙,于颊侧龈沟分别进行三种时间的排龈(5、10、15分钟),两次排龈间隔至少2周.制取排龈后的印模并灌制石膏模型.根据模型上牙龈不同位置牙龈与牙面的分离情况,对排龈效果由好到差进行0~3分的评分,其中0分及1分记为满意,比较不同排龈时间下排龈效果得分及满意率间的差异.结果 三种排龈时间的排龈效果得分存在统计学差异(P<0.05),随排龈时间的延长排龈效果满意率逐渐增大,排龈10分钟即可达到较好的排龈效果满意率.结论 在本实验条件下,印模制取前使用单线机械法排龈至少需要10分钟.%Objective To compare gingival retraction effects under three different types of retraction time, so as to provide references for dentists to choose gingival retraction time in clinical works. Methods Selecting 59 premolars or canines from 10 volunteers, for which gingival retraction cords were applied on the buccal sulcus under three different types of retraction time (5, 10 and 15 minutes) , respectively. The least interval between two retraction procedures was 2 weeks. Impressions and plaster models were made after gingival retraction. Based on the separation between gingival crest and tooth surface on different gingival areas of the models, gingival retraction effects from good to bad were graded from 0 to 3 score, in which 0 and 1 scores were considered to be acceptable. The scores and accepting rates of gingival retraction effects among different retraction time were compared and analyzed. Results There are statistical differences of the scores on gingival retraction effects under three types of retraction time ( P <0.05 ). The accepting rates of gingival retraction effects increased as gingival retraction time prolonged. A good accepting rate of gingival retraction effect could be

  19. Dendrite fragmentation in alloy solidification due to sidearm pinch-off.

    Science.gov (United States)

    Neumann-Heyme, H; Eckert, K; Beckermann, C

    2015-12-01

    Dendrite sidebranch detachment is an important fragmentation mechanism during the solidification of alloys. The detachment occurs at the junction between a sidearm and its parent stem. While this pinching process is driven by capillarity, the presence of solidification opposes the instability. Using a simple numerical model of a single sidearm, we are able to capture the essential dynamics of dendrite sidebranch development and the resulting morphological transitions. While shortly before pinch-off the neck itself obeys well-known universal scaling relations, the overall evolution of the sidearm shape sensitively depends on its initial geometry and the rate of solidification. It is found that pinch-off only occurs over limited ranges of geometrical parameters and cooling rates and is generally bounded by sidearm retraction and coalescence regimes. Simple scaling relations are identified that provide the bounds for the pinch-off regime. Pinching at the branching point is shown to be faster than the Rayleigh-Plateau instability of an infinitely long cylinder. PMID:26764615

  20. Manipulating Thermal Conductivity by Interfacial Modification of Misfit-Layered Cobaltites Ca3Co4O9

    Science.gov (United States)

    Fujii, Susumu; Yoshiya, Masato

    2016-03-01

    The phonon thermal conductivities of misfit-layered Ca3Co4O9, Sr3Co4O9, and Ba3Co4O9 were calculated using the perturbed molecular dynamics method to clarify the impact of lattice misfit on the phonon thermal conduction in misfit-layered cobaltites. Substitution of Sr and Ba for Ca substantially modified the magnitude of the lattice misfit between the CoO2 and rock salt (RS) layers, because of the different ionic radii, increasing overall phonon thermal conductivity. Further analyses with intentionally changed atomic masses of Ca, Sr, or Ba revealed that smaller ionic radius at the Ca site in the RS layer, instead of heavier atomic mass, is a critical factor suppressing the overall thermal conductivity of Ca3Co4O9, since it determines not only the magnitude of lattice misfit but also the dynamic interference between the two layers, which governs the phonon thermal conduction in the CoO2 and RS layers. This concept was demonstrated for Sr-doped Ca3Co4O9 as an example of atomistic manipulation for better thermoelectric properties. Phonon thermal conductivities not only in the RS layer but also in the CoO2 layer were reduced by the substitution of Sr for Ca. These results provide another strategy to improve the thermal conductivity of this class of misfit cobaltites, that is, to control the thermal conductivity of the CoO2 layer responsible for electronic and thermal conductivity by atomistic manipulation in the RS layer adjacent to the CoO2 layer.

  1. Prenatal hypoxia-ischemia induces abnormalities in CA3 microstructure, potassium chloride cotransporter 2 expression and inhibitory tone

    Directory of Open Access Journals (Sweden)

    Lauren L Jantzie

    2015-09-01

    Full Text Available Infants who suffer perinatal brain injury, including those with encephalopathy of prematurity, are prone to chronic neurological deficits including epilepsy, cognitive impairment, and behavioral problems such as anxiety, inattention and poor social interaction. These deficits, especially in combination, pose the greatest hindrance to these children becoming independent adults. Cerebral function depends on adequate development of essential inhibitory neural circuits and the appropriate amount of excitation and inhibition at specific stages of maturation. Early neuronal synaptic responses to γ-amino butyric acid (GABA are initially excitatory. During the early postnatal period, GABAAR responses switch to inhibitory with the upregulation of potassium-chloride co-transporter KCC2. With extrusion of chloride by KCC2, the Cl- reversal potential shifts and GABA and glycine responses become inhibitory. We hypothesized that prenatal hypoxic-ischemic brain injury chronically impairs the developmental upregulation of KCC2 that is essential for cerebral circuit formation. Following late gestation hypoxia-ischemia, diffusion tensor imaging in juvenile rats shows poor microstructural integrity in the hippocampal CA3 subfield, with reduced fractional anisotropy and elevated radial diffusivity. The loss of microstructure correlates with early reduced KCC2 expression on NeuN-positive pyramidal neurons, and decreased monomeric and oligomeric KCC2 protein expression in the CA3 subfield. Together with decreased IPSCs during a critical window of development, we document for the first time that prenatal transient systemic hypoxia-ischemia in rats impairs hippocampal CA3 inhibitory tone. Failure of timely development of inhibitory tone likely contributes to a lower seizure threshold and impaired cognitive function in children who suffer perinatal brain injury.

  2. Melamine Alters Glutamatergic Synaptic Transmission of CA3-CA1 Synapses Presynaptically Through Autophagy Activation in the Rat Hippocampus.

    Science.gov (United States)

    Zhang, Hui; Wang, Hui; Xiao, Xi; Zhang, Tao

    2016-01-01

    Melamine is an industrial chemical that can cause central nervous system disorders including excitotoxicity and cognitive impairment. Its illegal use in powdered baby formula was the focus of a milk scandal in China in 2008. One of our previous studies showed that melamine impaired glutamatergic transmission in rat hippocampal CA1 pyramidal cells. However, the underlying mechanism of action of melamine is unclear, and it is unknown if the CA3-CA1 pathway is directly involved. In the present study, a whole-cell patch-clamp technique was employed to investigate the effect of melamine on the hippocampal CA3-CA1 pathway in vitro. Both the evoked excitatory postsynaptic current (eEPSC) and the paired-pulse ratio (PPR) were recorded. Furthermore, we examined whether autophagy was involved in glutamatergic transmission alterations induced by melamine. Our data showed that melamine significantly increased the amplitude of eEPSCs in a dose-dependent manner. Inhibition of the N-methyl-D-aspartic acid receptor did not prevent the increase in eEPSC amplitude. In addition, the PPR was remarkably decreased by a melamine concentration of 5 × 10(-5) g/mL. It was found that autophagy could be activated by melamine and an autophagy inhibitor, 3-MA, prevented the melamine-induced increase in eEPSC amplitude. Overall, our results show that melamine presynaptically alters glutamatergic synaptic transmission of hippocampal CA3-CA1 synapses in vitro and this is likely associated with autophagy alteration. PMID:26530910

  3. Atomic-resolution study of charge transfer and structural disorder in thermoelectric Ca3Co4O9

    Science.gov (United States)

    Klie, Robert

    2010-03-01

    Thermoelectric oxides have attracted increasing attention due to their high thermal power and temperature stability. In particular, Ca3Co4O9, a misfit layered structure consisting of single layer hole-doped CoO2 sandwiched between insulating Ca2CoO3 rocksalt layers, exhibits figure of merit (ZT) of >1 at 1000 K.^1 It was suggested that the Seebeck-coefficient can be further increased by controlling the spin- and valence-state of the Co-ions in the CoO2 layers. This study combines aberration-corrected scanning transmission electron microscopy with electron energy loss spectroscopy (EELS) to examine the atomic and electronic structures of Ca3Co4O9. Using annular dark and bright field imaging, it will be demonstrated that the CoO2 layers are ordered, while the CoO columns in the Ca2CoO3 layer exhibit a modulation along (010). Atomic-column resolved EELS reveals that the Ca2CoO3 layers act as charge reservoirs providing mobile holes to the CoO2 layers; the structural disorder in Ca2CoO3 is responsible for the low in-plane thermal conductivity. The temperature dependence of the Co-ion spin-state as the origin for the unusually high Seebeck coefficient of Ca3O4O9 will be examined.^2 ^1 K. Fujita, et al., Jpn. J. Appl. Phys. 40 (2001), 4644--47^ ^2 Funded by: NSF CAREER Award DMR-0846748

  4. Superconducting properties of Cu1-xTlxBa2Ca3Cu4O12-y thin films

    International Nuclear Information System (INIS)

    Superconducting thin films with a predominant single phase of Cu1-xTlxBa2Ca3Cu4O12-y [Cu1-xTlx-1234] have been prepared for the first time by employing a two-step method. In this method the crystalline material was prepared from the sputtered amorphous phase by thallium treatment. This process was carried out at 900 deg. C for 1 h in an Au capsule. The amorphous phase was prepared by sputter deposition onto an SrTiO3 substrate from a stoichiometric target of composition CuBa2Ca3Cu4Ox. The films achieved after thallium treatment were aligned bi-axially along the a- and c-axes. XRD (x-ray diffraction) measurements showed a single-phase material with a c-axis lattice constant of 18.74 A. The c-axis lattice constant of Cu1-xTlx-1234 films is in between that of Cu-1234 (17.99 A) and Tl-1234 (19.11 A) superconductors. The pole figure measurements of 103 reflection of the films showed a-axis-oriented crystals with Δφ=0.8 deg. The composition of the films after EDX (energy dispersive x-ray spectroscopy) measurements was Cu0.3Tl0.7Ba2Ca3Cu4O12-y. From the resistivity measurements Tc was 110 K and Jc measurements showed a current density of 2.0x106 A cm-2 (77 K, 0 T). The preparation of Cu1-xTlx-1234 superconductor films by this method was highly reproducible. (author)

  5. Photoemission resonance study of sintered and single-crystal Bi4Ca3Sr3Cu4O16+x

    Science.gov (United States)

    Tang, Ming; Chang, Y.; Zanoni, R.; Onellion, M.; Joynt, Robert; Huber, D. L.; Margaritondo, G.; Morris, P. A.; Bonner, W. A.; Tarascon, J. M.; Stoffel, N. G.

    1989-02-01

    We present soft x-ray photoemission spectra that probe the valence and core electronic structure of the high-Tc superconductor Bi4Ca3Sr3Cu4O16+x. The identification of spectral features was helped by the observation of the resonant behavior of a Cu-related satellite feature. The resonance occurs at photon energies near the Cu3p optical absorption edge, and affects a peak 12.5 eV below the Fermi edge. We identified this feature as a correlation satellite characteristic of Cu in the 2+ valence state. Other features observed in the spectra more than 7 eV below the Fermi edge are due to several different core levels. In particular, we observed a strong Bi5d doublet. Other core level peaks are due to the Sr4p and Ca3p orbitals, and to Bi, Sr and Ca s-orbitals. Within 7 eV of the Fermi edge, the spectra are dominated by valence states. The most important feature is the Bi4Ca3Sr3Cu4O16+x Fermi edge itself, which we observed for the first time on this, and whose existence was subsequently confirmed by several other groups. On the contrary, no edge was observed in the photoemission spectra of materials in the YBa2Cu3O7-x family. The observation of the Fermi edge has important implications for the theoretical interpretation of high-Tc superconductivity. Furthermore, it enabled us to see near-edge changes associated with the superconducting transition.

  6. Differential long-term depression in CA3 but not in dentate gyrus following low-frequency stimulation of the medial perforant path.

    Science.gov (United States)

    Fung, Thomas K; Peloquin, Pascal; Wu, Kun; Leung, L Stan

    2011-07-01

    Synaptic plasticity may depend not only on the afferent fibers but also on the recipient structure. The medial perforant path (MPP) from the entorhinalcortex projects to both the dentate gyrus (DG) and CA3, resulting in excitatory postsynaptic potentials (EPSPs) in both areas. In this study, we showed that long-term depression (LTD) following low-frequency stimulation of MPP was found only in CA3a, a CA3 subfield, but not in DG. Field potentials were recorded and current source density (CSD) analyzed in CA3a and DG following stimulation of MPP in urethane-anesthetized rats. MPP evoked a short-latency population spike (PS) and EPSP in CA3a, phosphonovaleric acid or a nonselective group I/II metabotropic glutamate receptor (mGluR) antagonist (RS)-α-methyl-4-carboxyphenylglycine. We conclude that an NMDAR and mGluR sensitive LTD is induced in CA3 but not in the DG following low-frequency MPP stimulation in vivo, and the bi-directional synaptic plasticity in CA3 may be responsible for its behavioral functions. PMID:21190218

  7. The functional genome of CA1 and CA3 neurons under native conditions and in response to ischemia

    Directory of Open Access Journals (Sweden)

    Rossner Moritz

    2007-10-01

    Full Text Available Abstract Background The different physiological repertoire of CA3 and CA1 neurons in the hippocampus, as well as their differing behaviour after noxious stimuli are ultimately based upon differences in the expressed genome. We have compared CA3 and CA1 gene expression in the uninjured brain, and after cerebral ischemia using laser microdissection (LMD, RNA amplification, and array hybridization. Results Profiling in CA1 vs. CA3 under normoxic conditions detected more than 1000 differentially expressed genes that belong to different, physiologically relevant gene ontology groups in both cell types. The comparison of each region under normoxic and ischemic conditions revealed more than 5000 ischemia-regulated genes for each individual cell type. Surprisingly, there was a high co-regulation in both regions. In the ischemic state, only about 100 genes were found to be differentially expressed in CA3 and CA1. The majority of these genes were also different in the native state. A minority of interesting genes (e.g. inhibinbetaA displayed divergent expression preference under native and ischemic conditions with partially opposing directions of regulation in both cell types. Conclusion The differences found in two morphologically very similar cell types situated next to each other in the CNS are large providing a rational basis for physiological differences. Unexpectedly, the genomic response to ischemia is highly similar in these two neuron types, leading to a substantial attenuation of functional genomic differences in these two cell types. Also, the majority of changes that exist in the ischemic state are not generated de novo by the ischemic stimulus, but are preexistant from the genomic repertoire in the native situation. This unexpected influence of a strong noxious stimulus on cell-specific gene expression differences can be explained by the activation of a cell-type independent conserved gene-expression program. Our data generate both novel

  8. Altered mitochondria and Bcl-2 expression in the hippocampal CA3 region in a rat model of acute epilepsy

    Institute of Scientific and Technical Information of China (English)

    Jiyan Cheng; Lina Wu; Qiaozhi Wang; Yanfeng Gan; Guangyi Liu; Hong Yu

    2009-01-01

    BACKGROUND: Previous studies have shown that the mitochondrial structure and function are damaged in animal models of epilepsy. In addition, the Bcl-2 protein is capable of regulating mitochondrial stability.OBJECTIVE: To observe and validate changes in mitochondrial structure and Bcl-2 expression, and to analyze these characteristics in the hippocampal CA3 region of rat models of epilepsy. DESIGN, TIME AND SETTING: This randomized, controlled, animal experiment was performed at the Laboratory of Electron Microscopy and Department of Histology and Embryology, Luzhou Medical College between 2007 and 2008.MATERIALS: Coriamyrtin was provided by the Pharmacy Factory of West China University of Medical Sciences. The primary and secondary antibodies were provided by Zhongshan Goldenbridge Biotechnology, Beijing.METHODS: A total of 44 adult, male, Sprague Dawley rats were randomly divided into control (n=11) and epilepsy (n=33) groups. Rats in the epilepsy group were induced by coriamyrtin (50μg/kg), which was injected into the lateral ventricles. The rats were then observed at 3, 6, and 24 hours after epilepsy induction, with 11 rats at each time point. Epilepsy was not induced in rats from the control group.MAIN OUTCOME MEASURES: Pathological changes in the hippocampal CA3 region were observed by light microscopy; Bcl-2 expression was analyzed by immunohistochemistry; and mitochondrial changes in the hippocampus were observed under transmission electron microscopy.RESULTS: (1) The control group displayed very little Bcl-2 protein expression in the hippocampal CA3 region. However, after 3 hours of epilepsy, expression was visible. By 6 hours, expression peaked and then subsequently decreased after 24 hours, but remained higher than the control group (P<0.05). (2) Mitochondria were damaged to varying degrees in the epilepsy groups. For example, mitochondria edema, cristae space increase, and disappearance of mitochondria were apparent. Moreover, mitochondrial damage

  9. Evaluation of Ca3Co2O6 as cathode material for high-performance solid-oxide fuel cell

    OpenAIRE

    Tao Wei; Yun-Hui Huang; Rui Zeng; Li-Xia Yuan; Xian-Luo Hu; Wu-Xing Zhang; Long Jiang; Jun-You Yang; Zhao-Liang Zhang

    2013-01-01

    A cobalt-based thermoelectric compound Ca3Co2O6 (CCO) has been developed as new cathode material with superior performance for intermediate-temperature (IT) solid-oxide fuel cell (SOFC). Systematic evaluation has been carried out. Measurement of thermal expansion coefficient (TEC), thermal-stress (σ) and interfacial shearing stress (τ) with the electrolyte show that CCO matches well with several commonly-used IT electrolytes. Maximum power density as high as 1.47 W cm−2 is attained at 800°C, ...

  10. Magnetic phase separation in double layer ruthenates Ca3(Ru1−x Ti x )2O7

    OpenAIRE

    Jin Peng; Liu, J. Y.; J. Hu; Mao, Z. Q.; F. M. Zhang; Wu, X S

    2016-01-01

    A phase transition from metallic AFM-b antiferromagnetic state to Mott insulating G-type antiferromagnetic (G-AFM) state was found in Ca3(Ru1−x Ti x )2O7 at about x = 0.03 in our previous work. In the present, we focused on the study of the magnetic transition near the critical composition through detailed magnetization measurements. There is no intermediate magnetic phases between the AFM-b and G-AFM states, which is in contrasted to manganites where a similar magnetic phase transition takes...

  11. Lanthanides in phosphates with structure of vitlokite mineral [analog of β-Ca3(PO4)2

    International Nuclear Information System (INIS)

    Data on phosphates with structure of biogenic mineral vitlokite (analog of low-temperature modification of calcium phosphate β-Ca3(PO4)2) are analyzed. Possibility of isomorphism of cations in phosphates of such structure and formation of solid solutions with lanthanides is shown. Sol-gel method is used for synthesis of phosphates of Ca, Mg and Sm, Eu, and Gd. Characteristics of their thermal, thermal-mechanical and hydrolytic stability are determined. Results of hydrothermal and thermal tests are compared with literature data on Ca phosphate and other potential matrix materials for radioactive waste immobilization

  12. Growth kinetics of Cu1-xTlxBa2Ca3Cu4O12-y thin films

    International Nuclear Information System (INIS)

    Cu1-xTlxBa2Ca3Cu4O12-y (Cu1-xTlx-1234) thin films have been found to be very attractive candidates in the cuprate family due to their low superconductor anisotropy, long coherence length and, consequently, high Jc. The method of preparation has been reported previously, however the kinetics of their formation has not yet been studied. In this paper, we report on the growth kinetics of superconducting Cu1-xTlxBa2Ca3Cu4O12-y thin films. In the preparation, we use the amorphous phase epitaxy method, which is a thallium treatment of the amorphous phase at elevated temperatures. The amorphous phase was deposited on a SrTiO3 substrate by rf-sputtering from a stoichiometric target with a composition of CuBa2Ca3Cu4Oy. The thallium treatment of the amorphous phase was carried out in a gold capsule for 45 min. The mechanism of the growth kinetics has shown that the formation of Cu1-xTlxBa2Ca3Cu4O12-y thin films was accomplished from Cu1-xTlxBa2Ca1Cu2O8-y (Cu1-xTlx-1212) and Cu1-xTlxBa2Ca2Cu3O10-y (Cu1-xTlx-1223) by the successive introduction of CuO2 planes in these phases. We also studied the effect of the time and temperature of the thallium treatment on the growth of Cu1-xTlx-1234 films. The best synthesis temperature for Cu1-xTlx-1234 films was found to be 910 deg. C, but this phase could also be isolated as a single phase at lower temperatures (∼890 deg. C). However, the low-temperature synthesis results in a higher thallium content in the final compound. From the x-ray diffraction measurements the c-axis length was found to increase with the increase of the thallium content. The pole figure measurements of the (103) reflection of the films have shown a-axis oriented crystals with Δ φ = 0.8 deg. The observed critical temperature (Tc) for Cu1-xTlx-1212, Cu1-xTlx-1223 and Cu1-xTlx-1234 are 78 K, 103 K and 110 K respectively. Current density measurements have shown a maximum Jc∼2x106 A cm-2. (author)

  13. Discovery of a New Garnet Mineral, Ca_3Ti_2(SiAl_2)O_(12): An Alteration Phase in Allende

    OpenAIRE

    Ma, Chi; Krot, Alexander N.

    2013-01-01

    During a nanomineralogy investigation of the Allende CV3 carbonaceous chondrite, a new Ti-rich silicate, Ca_3Ti_2(SiAl_2)O_(12) with the Ia-3d garnet structure, was identified in the Type B1 Ca,Al-rich inclusion (CAI) Egg-3. Field-emission SEM with EDS and electron back-scatter diffraction and electron microprobe were used to characterize the composition and structure. Synthetic Ca_3Ti_2(SiAl_2)O_(12) is not reported. We present here the natural occurrence of Ca_3Ti_2(SiA...

  14. Renal dendritic cells: an update

    OpenAIRE

    Velázquez, Peter; Dustin, Michael L.; Peter J Nelson

    2009-01-01

    Discovery into the role of renal dendritic cells (rDCs) in health and disease of the kidney is rapidly accelerating. Progress in deciphering DC precursors and the heterogeneity of monocyte subsets in mice and humans are providing insights into the biology of rDCs. Recent findings have extended knowledge of the origins, anatomy, and function of the rDC network at steady-state and during periods of injury to the renal parenchyma. This brief review highlights these new findings and provides an u...

  15. Direct Microtubule-Binding by Myosin-10 Orients Centrosomes toward Retraction Fibers and Subcortical Actin Clouds.

    Science.gov (United States)

    Kwon, Mijung; Bagonis, Maria; Danuser, Gaudenz; Pellman, David

    2015-08-10

    Positioning of centrosomes is vital for cell division and development. In metazoan cells, spindle positioning is controlled by a dynamic pool of subcortical actin that organizes in response to the position of retraction fibers. These actin "clouds" are proposed to generate pulling forces on centrosomes and mediate spindle orientation. However, the motors that pull astral microtubules toward these actin structures are not known. Here, we report that the unconventional myosin, Myo10, couples actin-dependent forces from retraction fibers and subcortical actin clouds to centrosomes. Myo10-mediated centrosome positioning requires its direct microtubule binding. Computational image analysis of large microtubule populations reveals a direct effect of Myo10 on microtubule dynamics and microtubule-cortex interactions. Myo10's role in centrosome positioning is distinct from, but overlaps with, that of dynein. Thus, Myo10 plays a key role in integrating the actin and microtubule cytoskeletons to position centrosomes and mitotic spindles. PMID:26235048

  16. Retracted: Postoperative pain after irrigation with Vibringe versus a conventional needle: a randomized controlled trial.

    Science.gov (United States)

    Bilgili, D; Yilmaz, S; Dumani, A; Yoldas, O

    2016-08-01

    The following article from International Endodontic Journal, 'Postoperative pain after irrigation with Vibringe versus a conventional needle: a randomized controlled trial' by D. Bilgili, S. Yilmaz, A. Dumani & O. Yoldas, published online on 29 February 2016 in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the authors, the Journal Editor in Chief, Prof. Paul Dummer, and John Wiley & Sons Ltd. The retraction has been agreed because the corresponding author did not contact the first author who carried out the work before alterations to the article were made prior to submission. This damages the integrity of the work and there are additional concerns over the number of patients and the accuracy of the results and conclusions. PMID:26855328

  17. [Retracted] Clinical, pathological and genetic characteristics of autosomal dominant inherited dynamin 2 centronuclear myopathy.

    Science.gov (United States)

    Liu, Xinhong; Wu, Huamin; Gong, Jian; Wang, Tao; Yan, Chuanzhu

    2016-07-01

    We wish to retract our article entitled 'Clinical, pathological and genetic characteristics of autosomal dominant inherited dynamin 2 centronuclear myopathy' published in Molecular Medicine Reports 13: 4273-4278, 2016. The article was submitted by the first author, Xinhong Liu, without the prior knowledge of the corresponding author, Chuanzhu Yan, or the other authors included on the paper. Furthermore, the details of the paper were not discussed by the authors prior to the submission, and all are in agreement that the paper contains data therein (and interpretations thereof) which are either inaccurate or inappropriate. All the authors agree to this retraction, and we apologize for the inconvenience caused in this regard.[the original article was published in the Molecular Medicine Reports 13: 4273-4278, 2016; DOI: 10.3892/mmr.2016.5047]. PMID:27176730

  18. RETRACTED: The Application of Symmetric Key Cryptographic Algorithms in Wireless Sensor Networks

    Science.gov (United States)

    Si, Lingling; Ji, Zhigang; Wang, Zhihui

    This article has been retracted: please see Elsevier Policy on Article Withdrawal. This article has been retracted at the request of the Publisher. The authors have plagiarized a paper that had already appeared in "Queen's 25th Biennial Symposium on Communications", page 168-172, print ISBN 978-1-4244-5709-0, http://dx.doi.org/10.1109/BSC.2010.5472979. One of the conditions of submission of a paper for publication is that authors declare explicitly that their work is original and has not appeared in a publication elsewhere. Re-use of any data should be appropriately cited. As such this article represents a severe abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process.

  19. RETRACTED: On a general class of regular rotating black holes based on a smeared mass distribution

    Science.gov (United States)

    Larranaga, Alexis; Cardenas-Avendano, Alejandro; Torres, Daniel Alexdy

    2015-04-01

    This article has been retracted: please see Elsevier Policy on Article Withdrawal (href="http://www.elsevier.com/locate/withdrawalpolicy" This article has been retracted at the request of the Editor-in-Chief. The authors have plagiarized part of a paper that had already appeared in Adv. High Energy Physics, P. Nicolini, A. Orlandi, E. Spallucci, The Final Stage of Gravitationally Collapsed Thick Matter Layers, Vol 2013 (2013), Article ID 812084 http://dx.doi.org/10.1155/2013/812084. One of the conditions of submission of a paper for publication is that authors declare explicitly that their work is original and has not appeared in a publication elsewhere. Re-use of any data should be appropriately cited. As such this article represents a severe abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process.

  20. 不同排龈药物的排龈效果观察%The retractive effects of different gingival retraction agents

    Institute of Scientific and Technical Information of China (English)

    冯云枝; 曾晓华

    2011-01-01

    Objective To evaluate the retractive effects of different gingival retraction agents. Methods Thirty subjects with healthy gingival conditions were recruited to the trial, and the buccal gingival sulcns of the hibateral first max-illary premolars of each subject (n=60) were treated randomly with one of the six agents-Group A was tetrahydrozoline hydrochloride, Group B was oxymetazoline hydrochloride, Group C was epinephrine hydrochlorid, Group D was AlCl3, Group E was Fe2 (S04)3, and Group F was normal saline as control. Both pre-treated and post-treated accurate impressions of buccal gingival sulcus of the experimental teeth were made, so were the anhydrite casts. The casts of experimental teeth were sectioned into 2 mm slices bucco-lingually at the buccal eminence. Then the width of the sulcus was measured as the distance from the tooth to the crest of the gingival under a low-power microscope to compare the effect of these giagival retraction agents. Results The width of gingival sulcus became larger after the treatment in all groups(P<0.05). Either Group A or Group B had greater gingival retraction effects than Group C and Group F (P<0.05). Except Group F, both Group D and Group E had no significant differences from the other groups (P>0.05). There was no statistically signification between Group D and Group E (P>0.05), neither was there any statistically significance between Group A and Group B (P>0.05). Conclusion Tetrahydrozoline manifested excellent effect of gingival retraction.%目的 观察不同排龈药物的排龈效果.方法选择30例志愿者的双侧上颌第一前磨牙(共60颗)作为研究牙齿,随机分成A~F共6组,分别使用含不同排龈药物的排龈线进行颊侧排龈处理.A组为盐酸四氢唑啉,B组为盐酸羟甲唑啉组,C组为盐酸肾上腺素,D组为氯化铝,E组为硫酸铁,F组为生理盐水.于排龈前后分别精确取模,获得排龈牙颊侧龈沟的清晰印模,在硬石膏模型上沿牙冠长轴

  1. Gingival Retraction Methods for Fabrication of Fixed Partial Denture: Literature Review

    OpenAIRE

    Safari S; Vossoghi Sheshkalani Ma; Vossoghi Sheshkalani Mi; Hoseini Ghavam F; Hamedi M

    2016-01-01

    Fixed dental prosthesis success requires appropriate impression taking of the prepared finish line. This is critical in either tooth supported fixed prosthesis (crown and bridge) or implant supported fixed prosthesis (solid abutment). If the prepared finish line is adjacent to the gingival sulcus, gingival retraction techniques should be used to decrease the marginal discrepancy among the restoration and the prepared abutment. Accurate marginal positioning of the restoration in the prepared f...

  2. Actin turnover is required to prevent axon retraction driven by endogenous actomyosin contractility

    OpenAIRE

    Gallo, Gianluca; Yee, Hal F.; Letourneau, Paul C.

    2002-01-01

    Growth cone motility and guidance depend on the dynamic reorganization of filamentous actin (F-actin). In the growth cone, F-actin undergoes turnover, which is the exchange of actin subunits from existing filaments. However, the function of F-actin turnover is not clear. We used jasplakinolide (jasp), a cell-permeable macrocyclic peptide that inhibits F-actin turnover, to study the role of F-actin turnover in axon extension. Treatment with jasp caused axon retraction, demonstrating that axon ...

  3. Comparison of canine retraction using single and Siamese edgewise brackets: An in vivo study

    Directory of Open Access Journals (Sweden)

    Zeeshan Iqbal Bhat

    2013-01-01

    Full Text Available Objectives: The purpose of this study was to check the rate of canine retraction with bodily mechanics using two different pre-adjusted edgewise bracket Systems. Materials and Methods: A split mouth study with twenty patients who were randomly selected and allotted to a single operator. Duration of canine retraction, angulation of canine during its retraction, degree of Rotation, anchorage Loss, distance between canine and premolar at different time intervals were then evaluated, pre- (To, 3 months- (T1 and canine tip touches the second premolar- (T2. Descriptive statistics including mean values and standard deviations were calculated. Paired and unpaired t-test was performed to evaluate the differences between the groups. Results: Rotation and angulation of the canines did not show significant difference in both the systems. There was statistically significant difference (P<0.01 in anchorage loss between single wing and Siamese bracket being 2.65 ±1.41 mm and 1.31 ± 0.93 respectively. There was statistically significant intergroup difference (P<0.01 in canine movement i.e distance between canine and premolar was recorded as 4.72mm (15.06 ± 1.69 to 10.34 ± 1.68mm in single wing bracket and 6.25mm in Siamese (15.52 ± 1.41 to 9.27 ± 1.94. Conclusion: In cases where high anchorage is required and the rate of canine retraction is a concern, Siamese brackets pose a definite advantage over Single wing brackets.

  4. "Demographic faultlines: A meta-analysis of the literature": Retraction of Thatcher and Patel (2011).

    Science.gov (United States)

    2016-08-01

    Reports the retraction of "Demographic faultlines: A meta-analysis of the literature" by Sherry M. B. Thatcher and Pankaj C. Patel (, 2011[Nov], Vol 96[6], 1119-1139). At the request of the editor and in consultation with the American Psychological Association, the article is being retracted. This action is a result of a review by the editor and two additional experts that determined that there are significant errors in Tables 1, 2, and 3 which may affect the overall conclusions of the article. Co-author Pankaj C. Patel led the analysis, and both authors acknowledge that inaccuracies were made. The retraction of this article does not preclude resubmission of a new article that addresses the issues noted in the retraction. (The following abstract of the original article appeared in record .) We propose and test a theoretical model focusing on antecedents and consequences of demographic faultlines. We also posit contingencies that affect overall team dynamics in the context of demographic faultlines, such as the study setting and performance measurement. Using meta-analysis structural equation modeling with a final data set consisting of 311 data points (i.e., [predictor-criterion relationships]), from 39 studies that were obtained from 36 papers with a total sample size of 24,388 individuals in 4,366 teams, we found that sex and racial diversity increased demographic faultline strength more than did diversity on the attributes of functional background, educational background, age, and tenure. Demographic faultline strength was found to increase task and relationship conflict as well as decrease team cohesion. Furthermore, although demographic faultline strength decreased both team satisfaction and team performance, there was a stronger decrease in team performance than in team satisfaction. The strength of these relationships increased when the study was conducted in the lab rather than in the field. We describe the theoretical and practical implications of these

  5. Eugregarine trophozoite detachment from the host epithelium via epimerite retraction: Fiction or fact?

    Czech Academy of Sciences Publication Activity Database

    Valigurová, A.; Michalková, V.; Koudela, Břetislav

    2009-01-01

    Roč. 39, č. 11 (2009), s. 1235-1242. ISSN 0020-7519 R&D Projects: GA MŠk LC522 Grant ostatní: GA MŠk(CZ) MSM0021622416 Institutional research plan: CEZ:AV0Z60220518 Keywords : Apicomplexa * epimerite retraction * trophozoite Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine Impact factor: 3.819, year: 2009

  6. Two-dimensional wave patterns of spreading depolarization: retracting, re-entrant, and stationary waves

    OpenAIRE

    Dahlem, Markus A.; Graf, Rudolf; Strong, Anthony J.; Dreier, Jens P.; Dahlem, Yuliya A.; Sieber, Michaela; Hanke, Wolfgang; Podoll, Klaus; Schoell, Eckehard

    2009-01-01

    We present spatio-temporal characteristics of spreading depolarizations (SD) in two experimental systems: retracting SD wave segments observed with intrinsic optical signals in chicken retina, and spontaneously occurring re-entrant SD waves that repeatedly spread across gyrencephalic feline cortex observed by laser speckle flowmetry. A mathematical framework of reaction-diffusion systems with augmented transmission capabilities is developed to explain the emergence and transitions between the...

  7. A comparative study of frictional resistance during simulated canine retraction on typodont model

    OpenAIRE

    Sukh, Ram; Singh, Gulshan K; Tandon, Pradeep; Singh, Gyan P.; SINGH Alka

    2013-01-01

    Objectives: Frictional resistance is an important counterforce to orthodontic tooth movement during sliding mechanics. This study was carried out to evaluate the effect of different bracket-archwire-ligation combinations on “resistance to sliding” during simulated canine retraction on typodont model. Materials and Methods: the frictional resistance was tested between three modern orthodontic brackets-stainless steel, ceramic, and ceramic with metal slot (0.022-inch), and seven different archw...

  8. RETRACT OF CONSENT, UNDER THE REGULATION OF THE ROMANIAN CONSUMPTION LAW

    OpenAIRE

    JUANITA GOICOVICI

    2011-01-01

    The article encompasses the four main zones of incidence, in the Romanian legislation, of the consumer’s right to retract the prior consent, namely the contracts concluded outside commercial spaces, contracts agreed at distance, including electronic bargains, credits offered to consumers and time-sharing contracts. First, we briefly discuss the various possibilities of consent withdrawal, as described by national law and examine the discretionary character of withdrawal rights. Next, attentio...

  9. Vertical solidification of dendritic binary alloys

    Science.gov (United States)

    Heinrich, J. C.; Felicelli, S.; Poirier, D. R.

    1991-01-01

    Three numerical techniques are employed to analyze the influence of thermosolutal convection on defect formation in directionally solidified (DS) alloys. The finite-element models are based on the Boussinesq approximation and include the plane-front model and two plane-front models incorporating special dendritic regions. In the second model the dendritic region has a time-independent volume fraction of liquid, and in the last model the dendritic region evolves as local conditions dictate. The finite-element models permit the description of nonlinear thermosolutal convection by treating the dendritic regions as porous media with variable porosities. The models are applied to lead-tin alloys including DS alloys, and severe segregation phenomena such as freckles and channels are found to develop in the DS alloys. The present calculations and the permeability functions selected are shown to predict behavior in the dendritic regions that qualitatively matches that observed experimentally.

  10. Early events in axon/dendrite polarization.

    Science.gov (United States)

    Cheng, Pei-lin; Poo, Mu-ming

    2012-01-01

    Differentiation of axons and dendrites is a critical step in neuronal development. Here we review the evidence that axon/dendrite formation during neuronal polarization depends on the intrinsic cytoplasmic asymmetry inherited by the postmitotic neuron, the exposure of the neuron to extracellular chemical factors, and the action of anisotropic mechanical forces imposed by the environment. To better delineate the functions of early signals among a myriad of cellular components that were shown to influence axon/dendrite formation, we discuss their functions by distinguishing their roles as determinants, mediators, or modulators and consider selective degradation of these components as a potential mechanism for axon/dendrite polarization. Finally, we examine whether these early events of axon/dendrite formation involve local autocatalytic activation and long-range inhibition, as postulated by Alan Turing for the morphogenesis of patterned biological structure. PMID:22715881

  11. Filopodial retraction force is generated by cortical actin dynamics and controlled by reversible tethering at the tip

    DEFF Research Database (Denmark)

    Bornschlögl, Thomas; Romero, Stéphane; Vestergaard, Christian L.;

    2013-01-01

    Filopodia are dynamic, finger-like plasma membrane protrusions that sense the mechanical and chemical surroundings of the cell. Here, we show in epithelial cells that the dynamics of filopodial extension and retraction are determined by the difference between the actin polymerization rate at the...... tip and the retrograde flow at the base of the filopodium. Adhesion of a bead to the filopodial tip locally reduces actin polymerization and leads to retraction via retrograde flow, reminiscent of a process used by pathogens to invade cells. Using optical tweezers, we show that filopodial retraction...... occurs at a constant speed against counteracting forces up to 50 pN. Our measurements point toward retrograde flow in the cortex together with frictional coupling between the filopodial and cortical actin networks as the main retraction-force generator for filopodia. The force exerted by filopodial...

  12. Critical points in the Bragg glass phase of a weakly pinned crystal of Ca3Rh4Sn13

    Indian Academy of Sciences (India)

    S Sarkar; A D Thakur; C V Tomy; G Balakrishnan; D McK Paul; S Ramakrishnan; A K Grover

    2006-01-01

    New experimental data are presented on the scan rate dependence of the magnetization hysteresis width () (∝ critical current density c()) in isothermal - scans in a weakly pinned single crystal of Ca3Rh4Sn13, which displays second magnetization peak (SMP) anomaly as distinct from the peak effect (PE). We observe an interesting modulation in the field dependence of a parameter which purports to measure the dynamical annealing of the disordered bundles of vortices injected through the sample edges towards the destined equilibrium vortex state at a given . These data, in conjunction with the earlier observations made while studying the thermomagnetic history dependence in c() in the tracing of the minor hysteresis loops, imply that the partially disordered state heals towards the more ordered state between the peak field of the SMP anomaly and the onset field of the PE. The vortex phase diagram in the given crystal of Ca3Rh4Sn13 has been updated in the context of the notion of the phase coexistence of the ordered and disordered regions between the onset field of the SMP anomaly and the spinodal line located just prior to the irreversibility line. A multi-critical point and a critical point in the (, ) region of the Bragg glass phase have been marked in this phase diagram and the observed behavior is discussed in the light of recent data on multi-critical point in the vortex phase diagram in a single crystal of Nb.

  13. Effect of the nanometric scale thickness on the magnetization steps in Ca3Co2O6 thin films

    Science.gov (United States)

    Moubah, Reda; Colis, Silviu; Ulhaq-Bouillet, Corinne; Drillon, Marc; Dinia, Aziz

    2011-07-01

    We report on the effect of the film thickness on the magnetic properties of Ca3Co2O6 films with an emphasis on the magnetization steps usually observed in the M-H curves below 10 K. Films with thicknesses between 35 and 200 nm all present two magnetic transitions at about TC1 = 22 K and TC2 = 10 K, corresponding to a 3D long range ferrimagnetic order and the transition to the formation of a frozen spin state, respectively. The magnetization curves at 10 K exhibit the expected stepped variation. However, by decreasing the thickness below a critical value of about 60 nm, no magnetization plateau is observed when the M-H curve is recorded at 2 K. Moreover, an additional transition in the susceptibility curve is observed at 45 K. These changes can be attributed to the reduced coherence length of the propagation vector along and perpendicular to the chains, and are supported by the magnetization relaxation measurements which indicate a reduction of the relaxation time. These results are helpful for understanding the origin of the magnetization steps in the one-dimensional Ca3Co2O6 cobaltite and confront the theoretical models aimed at explaining the magnetic properties in this system.

  14. Luminescence and energy transfer in Ca3Sc2Si3O12:Ce3+,Mn2+ white LED phosphors

    International Nuclear Information System (INIS)

    Expanded emission spectra ranging from green to red are reported in Ca3Sc2Si3O12 (CSS):Ce3+,Mn2+ silicate garnets. Mn2+ may occupy Ca2+ site (Mn2+(I)) to generate a yellow emission band at 574 nm or Sc3+ site (Mn2+(II)) with red emission band at 680 nm. Efficient energy transfers from the green emitting Ce3+ to both Mn2+(I) and Mn2+(II) occur upon blue excitation into Ce3+. Concentration dependence of Mn2+ emission is analyzed based on Ce3+–Mn2+ energy transfer, steady state rate equations, and fluorescence lifetimes. Energy transfer efficiency (ηT) and rate (W) are calculated with values as high as 45% and 14.01×106 s−1, respectively. - Highlights: ► Mn2+ can occupy Ca2+ site to generate a yellow emission band at 574 nm in Ca3Sc2Si3O12 (CSS). ► Mn2+ can also occupy Sc3+ site to generate a red emission band at 680 nm in CSS. ► Remarkable energy transfers (ETs) from Ce3+ to Mn2+ occur upon blue excitation into Ce3+ in CSS. ► Full color emissions are obtained based on Ce3+–Mn2+ ETs in CSS:Ce3+,Mn2+.

  15. Microstructure and Thermoelectric Properties of Bi- and Cu-Substituted Ca3Co4O9 Oxides

    Institute of Scientific and Technical Information of China (English)

    Haoshan Hao; Limin Zhao; Xing Hu

    2009-01-01

    Bi- and Cu-substituted Ca3Co4O9 samples were prepared by conventional solid-state reaction method and the effect of element substitution on the microstructures and thermoelectric properties was investigated. Partial substitution of Cu for Co leads to an increase in electrical conductivity and a decrease in Seebeck coefficient due to the rise of hole concentration. The microstructure of Cu-substituted sample is almost unchanged compared with undoped Ca3Co4O9. On the other hand, partial substitution of Bi for Ca gives rise to a significant increase in the grain size, and c-axis-oriented structure can be formed in Ca2.7Bi0.3Co4O9, resulting in an obvious increase in electrical conductivity. Cu and Bi co-substitution further increases the grain growth and the electrical conductivity of Ca2.7Bi0.3Co3.7Cu0.3O9. Thus, Cu and Bi co-substitution samples possess the optimal thermoelectric performance at high temperature and the highest value of power factor can reach 3.1×10-4 Wm-1·K-2 at 1000 K.

  16. Spectral variations of Ca3Sc2Si3O12:Ce phosphors via substitution and energy transfer

    Institute of Scientific and Technical Information of China (English)

    LIU Yuanhong; ZHUANG Weidong; LIU Ronghui; HU Yunsheng; HE Huaqiang; ZHANG Shusheng; GAO Wei

    2012-01-01

    The luminescence intensity of emission peak at around 525 nm decreased in the Ce3+ and Er3+ co-doped Ca3Sc2Si3O12 phosphors.Mg2+ ion,which was likely incorporated into the Sc3+ position of the host crystal,was co-doped to adjust the crystal field and compensate for the excess positive charge due to the doping of Ce3+.The green emission belonged to the 5d→4f transition of Ce3+ moved toward longer wavelength by addition of Mg2+ in Ce3+ and Er3+ co-doped Ca3Sc2Si3O12 phosphor,which could increase the brightness of the phosphor.However,the position of weakening of luminescence intensity at around 525 nm remained basically unchanged by increasing the amount of Mg2+.The results showed that the weakening of luminescence intensity at around 525 nm caused by the absorption of Er3+,which had littleinfluence on the environment of the crystal field.

  17. Intraluminal magnetisation of bowel by ferromagnetic particles for retraction and manipulation by magnetic probes.

    Science.gov (United States)

    Wang, Z; André, P; McLean, D; Brown, S I; Florence, G J; Cuschieri, A

    2014-11-01

    Feasibility studies are needed to demonstrate that safe and effective manipulation of bowel during Minimal Access Surgery (MAS) can be obtained by use of magnetic force. This paper characterises two classes of magnetic particles: stainless steel microparticles (SS-μPs) and iron oxide nanoparticles (IO-nPs) in terms of their magnetisation, chemical composition, crystallinity, morphology and size distribution. Both magnetic particles were dispersed in a high viscosity biological liquid for intraluminal injection of bowel. Ex vivo porcine bowel segments were then retracted by permanent magnetic probes of 5.0 and 10mm diameter. Strong retraction forces reaching 6N maximum were obtained by magnetic fluid based on dispersion of SS-μPs. In contrast, the IO-nP-based magnetic liquid generated less attraction force, due to both lower magnetic and solution properties of the IO-nPs. The comparison of the two particles allowed the identification of the rules to engineer the next generation of particles. The results with SS-μPs provide proof on concept that intraluminal injection of magnetic fluid can generate sufficient force for efficient bowel retraction. Thereafter we shall carry out in vivo animal studies for efficacy and safety of both types of ferrofluids. PMID:25169469

  18. One-dimensional steady continuum model of retraction of pseudopod in leukocytes.

    Science.gov (United States)

    Zhu, C; Skalak, R; Schmid-Schönbein, G W

    1989-02-01

    A one-dimensional steady state continuum mechanics model of retraction of pseudopod in leukocytes is developed. The retracting pseudopod is assumed to move bodily toward the main cell body, the bulk motion of which can be represented by cytoplasmic flow within a typical stream tube through the leukocyte. The stream tube is approximated by a frictionless tube with prescribed geometry. The passive rheological properties of cytoplasm in the main cell body and in the pseudopod are modeled, respectively, by Maxwell fluid and Hookean solid. The two regions are assumed to be separated by a sharp interface at which actin gel solates and thereby changes its rheological properties as it flows from the pseudopod to the main cell body. The driving mechanism responsible for the active retraction motion is hypothesized to be a spontaneous deformation of the actin gel, analogous but not necessarily equal to the well known actin-myosin interaction. This results in an active contractile stress being developed in the pseudopod as well as in the cell cortex. The transverse traction pulls against the inclined wall of the stream tube and is transduced into an axial stress gradient, which in turn drives the flow. The tension on the tube wall is picked up by the prestressed cortical shell. Governing equations and boundary conditions are derived. A solution is obtained. Sample data are computed. Comparison of the theory with experiments shows that the model is compatible to the observations. PMID:2747236

  19. Canine retraction and anchorage loss self-ligating versus conventional brackets: a systematic review and meta-analysis

    OpenAIRE

    Zhou, Qiaozhen; ul Haq, Abdul Azeem Amin; Tian, Liu; Chen, Xiaofeng; Huang, Kui; Zhou, Yu

    2015-01-01

    Background The purpose of this systematic review is to identify and review the orthodontic literature with regards to assessing possible differences in canine retraction rate and the amount of antero-posterior anchorage (AP) loss during maxillary canine retraction, using conventional brackets (CBs) and self-ligating brackets (SLBs). Methods An electronic search without time or language restrictions was undertake in September 2014 in the following electronic databases: The Cochrane Oral Health...

  20. Engineering crystals of dendritic molecules.

    Science.gov (United States)

    Lukin, Oleg; Schubert, Dirk; Müller, Claudia M; Schweizer, W Bernd; Gramlich, Volker; Schneider, Julian; Dolgonos, Grygoriy; Shivanyuk, Alexander

    2009-07-01

    A detailed single-crystal X-ray study of conformationally flexible sulfonimide-based dendritic molecules with systematically varied molecular architectures was undertaken. Thirteen crystal structures reported in this work include 9 structures of the second-generation dendritic sulfonimides decorated with different aryl groups, 2 compounds bearing branches of both second and first generation, and 2 representatives of the first generation. Analysis of the packing patterns of 9 compounds bearing second-generation branches shows that despite their lack of strong directive functional groups there is a repeatedly reproduced intermolecular interaction mode consisting in an anchor-type packing of complementary second-generation branches of neighbouring molecules. The observed interaction tolerates a wide range of substituents in meta- and para-positions of the peripheral arylsulfonyl rings. Quantum chemical calculations of the molecule-molecule interaction energies agree at the qualitative level with the packing preferences found in the crystalline state. The calculations can therefore be used as a tool to rationalize and predict molecular structures with commensurate and non-commensurate branches for programming of different packing modes in crystal. PMID:19549870

  1. Deposition, structure, physical and invitro characteristics of Ag-doped β-Ca3(PO4)2/chitosan hybrid composite coatings on Titanium metal.

    Science.gov (United States)

    Singh, Ram Kishore; Awasthi, Sharad; Dhayalan, Arunkumar; Ferreira, J M F; Kannan, S

    2016-05-01

    Pure and five silver-doped (0-5Ag) β-tricalcium phosphate [β-TCP, β-Ca3(PO4)2]/chitosan composite coatings were deposited on Titanium (Ti) substrates and their properties that are relevant for applications in hard tissue replacements were assessed. Silver, β-TCP and chitosan were combined to profit from their salient and complementary antibacterial and biocompatible features.The β-Ca3(PO4)2 powders were synthesized by co-precipitation. The characterization results confirmed the Ag(+) occupancy at the crystal lattice of β-Ca3(PO4)2. The Ag-dopedβ-Ca3(PO4)2/chitosan composite coatings deposited by electrophoresis showed good antibacterial activity and exhibited negative cytotoxic effects towards the human osteosarcoma cell line MG-63. The morphology of the coatings was observed by SEM and their efficiency against corrosion of metallic substrates was determined through potentiodynamic polarization tests. PMID:26952474

  2. Lever-arm and mini-implant system for anterior torque control during retraction in lingual orthodontic treatment.

    Science.gov (United States)

    Hong, Ryoon-Ki; Heo, Jung-Min; Ha, Young-Ki

    2005-01-01

    Anterior torque control during retraction is difficult to achieve with lingual orthodontic treatment. This article describes the use of a lever-arm and mini-implant system as absolute anchorage for controlled retraction of the anterior teeth during lingual orthodontic treatment and evaluates 2 protrusion cases treated with this system. Various clinical situations are discussed and analyzed from a biomechanical standpoint. Mini-implants are needed to control the point of force application in the posterior area and produce en masse retraction with no anchorage loss. When the length of the lever-arm is adjusted to the position of the mini-implant, the desired line of action of the retraction force with respect to the center of resistance of the anterior segment is selected. Controlled retraction of the anterior teeth was achieved with no loss of anchorage. The mini-implant, in conjunction with the lever-arm, is useful not only for absolute anchorage but also for anterior torque control during retraction in lingual orthodontic treatment. PMID:15747828

  3. Reduced Hippocampal Dendritic Spine Density and BDNF Expression following Acute Postnatal Exposure to Di(2-Ethylhexyl) Phthalate in Male Long Evans Rats

    Science.gov (United States)

    Smith, Catherine A.; Holahan, Matthew R.

    2014-01-01

    Early developmental exposure to di(2-ethylhexyl) phthalate (DEHP) has been linked to a variety of neurodevelopmental changes, particularly in rodents. The primary goal of this work was to establish whether acute postnatal exposure to a low dose of DEHP would alter hippocampal dendritic morphology and BDNF and caspase-3 mRNA expression in male and female Long Evans rats. Treatment with DEHP in male rats led to a reduction in spine density on basal and apical dendrites of neurons in the CA3 dorsal hippocampal region compared to vehicle-treated male controls. Dorsal hippocampal BDNF mRNA expression was also down-regulated in male rats exposed to DEHP. No differences in hippocampal spine density or BDNF mRNA expression were observed in female rats treated with DEHP compared to controls. DEHP treatment did not affect hippocampal caspase-3 mRNA expression in male or female rats. These results suggest a gender-specific vulnerability to early developmental DEHP exposure in male rats whereby postnatal DEHP exposure may interfere with normal synaptogenesis and connectivity in the hippocampus. Decreased expression of BDNF mRNA may represent a molecular mechanism underlying the reduction in dendritic spine density observed in hippocampal CA3 neurons. These findings provide initial evidence for a link between developmental exposure to DEHP, reduced levels of BDNF and hippocampal atrophy in male rats. PMID:25295592

  4. Preliminary X-ray crystallographic analysis of β-carbonic anhydrase psCA3 from Pseudomonas aeruginosa

    International Nuclear Information System (INIS)

    Two crystal forms of β-carbonic anhydrase psCA3 from P. aeruginosa were grown. Crystal form A belonged to space group P212121, with unit-cell parameters a = 81.9, b = 84.9, c = 124.2 Å, and diffracted X-rays to 2.9 Å resolution; crystal form B belonged to space group P21212, with unit-cell parameters a = 69.9, b = 77.7, c = 88.5 Å, and diffracted X-rays to 3.0 Å resolution. Pseudomonas aeruginosa is a Gram-negative bacterium that causes life-threatening infections in susceptible individuals and is resistant to most clinically available antimicrobials. Genomic and proteomic studies have identified three genes, pa0102, pa2053 and pa4676, in P. aeruginosa PAO1 encoding three functional β-carbonic anhydrases (β-CAs): psCA1, psCA2 and psCA3, respectively. These β-CAs could serve as novel antimicrobial drug targets for this pathogen. X-ray crystallographic structural studies have been initiated to characterize the structure and function of these proteins. This communication describes the production of two crystal forms (A and B) of β-CA psCA3. Form A diffracted to a resolution of 2.9 Å; it belonged to space group P212121, with unit-cell parameters a = 81.9, b = 84.9, c = 124.2 Å, and had a calculated Matthews coefficient of 2.23 Å3 Da−1 assuming four molecules in the crystallographic asymmetric unit. Form B diffracted to a resolution of 3.0 Å; it belonged to space group P21212, with unit-cell parameters a = 69.9, b = 77.7, c = 88.5 Å, and had a calculated Matthews coefficient of 2.48 Å3 Da−1 assuming two molecules in the crystallographic asymmetric unit. Preliminary molecular-replacement solutions have been determined with the PHENIX AutoMR wizard and refinement of both crystal forms is currently in progress

  5. Piezoelectric Ca3NbGa3Si2O14 crystal: crystal growth, piezoelectric and acoustic properties

    Science.gov (United States)

    Roshchupkin, Dmitry; Ortega, Luc; Plotitcyna, Olga; Erko, Alexei; Zizak, Ivo; Vadilonga, Simone; Irzhak, Dmitry; Emelin, Evgenii; Buzanov, Oleg; Leitenberger, Wolfram

    2016-08-01

    Ca3NbGa3Si2O14 (CNGS), a five-component crystal of lanthanum-gallium silicate group, was grown by the Czochralski method. The parameters of the elementary unit cell of the crystal were measured by powder diffraction. The independent piezoelectric strain coefficients d{}_{11} and d_{14} were determined by the triple-axis X-ray diffraction in the Bragg and Laue geometries. Excitation and propagation of surface acoustic waves (SAW) were studied by high-resolution X-ray diffraction at BESSY II synchrotron radiation source. The velocity of SAW propagation and power flow angles in the Y-, X- and yxl/{+}36°-cuts of the CNGS crystal were determined from the analysis of the diffraction spectra. The CNGS crystal was found practically isotropic by its acoustic properties.

  6. Neural stem cell activation and glial proliferation in the hippocampal CA3 region of posttraumatic epileptic rats

    Institute of Scientific and Technical Information of China (English)

    Yuanxiang Lin; Kun Lin; Dezhi Kang; Feng Wang

    2011-01-01

    The present study observed the dynamic expression of CD133, nuclear factor-κB and glial fibrillary acidic protein in the hippocampal CA3 area of the experimental posttraumatic epilepsy rats to investigate whether gliosis occurs after posttraumatic epilepsy. CD133 and nuclear factor-κB expression was increased at 1 day after posttraumatic epilepsy, peaked at 7 days, and gradually decreased up to 14 days, as seen by double-immunohistochemical staining. Glial fibrillary acidic protein/nuclear factor-κB double-labeled cells increased with time and peaked at 14 days after posttraumatic epilepsy. Results show that activation of hippocampal neural stem cells and glial proliferation after posttraumatic epilepsy-induced oxidative stress increases hippocampal glial cell density.

  7. Evaluation of Ca3Co2O6 as cathode material for high-performance solid-oxide fuel cell.

    Science.gov (United States)

    Wei, Tao; Huang, Yun-Hui; Zeng, Rui; Yuan, Li-Xia; Hu, Xian-Luo; Zhang, Wu-Xing; Jiang, Long; Yang, Jun-You; Zhang, Zhao-Liang

    2013-01-01

    A cobalt-based thermoelectric compound Ca(3)Co(2)O(6) (CCO) has been developed as new cathode material with superior performance for intermediate-temperature (IT) solid-oxide fuel cell (SOFC). Systematic evaluation has been carried out. Measurement of thermal expansion coefficient (TEC), thermal-stress (σ) and interfacial shearing stress (τ) with the electrolyte show that CCO matches well with several commonly-used IT electrolytes. Maximum power density as high as 1.47 W cm(-2) is attained at 800°C, and an additional thermoelectric voltage of 11.7 mV is detected. The superior electrochemical performance, thermoelectric effect, and comparable thermal and mechanical behaviors with the electrolytes make CCO to be a promising cathode material for SOFC. PMID:23350032

  8. Structural and magnetic anomalies among the spin-chain compounds, Ca3Co1+Ir1-O6

    Indian Academy of Sciences (India)

    S Rayaprol; Kausik Sengupta; E V Sampathkumaran

    2003-10-01

    The results of X-ray diffraction, and ac and dc magnetisation as a function of temperature are reported for a new class of spin-chain oxides, Ca3Co1+Ir1-O6. While the = 0.0, 0.3, 0.5 and 1.0 are found to form in the K4CdCl6-derived rhombhohedral (space group $\\bar{3}$) structure, the = 0.7 composition is found to undergo a monoclinic distortion in contrast to a literature report. Apparently, the change in the crystal symmetry with x manifests itself as a change in the sign of paramagnetic Curie temperature for this composition as though magnetic coupling sensitively depends on such crystallographic distortions. All the compositions exhibit spin-glass anomalies with an unusually large frequency dependence of the peak temperature in susceptibility in a temperature range below 50 K, interestingly obeying Vogel-Fulcher relationship even for the stoichiometric compounds.

  9. Size and receptor density of glutamatergic synapses: a viewpoint from left-right asymmetry of CA3-CA1 connections

    Directory of Open Access Journals (Sweden)

    Yoshiaki Shinohara

    2009-07-01

    Full Text Available Synaptic plasticity is considered to be the main mechanism for learning and memory. Excitatory synapses in the cerebral cortex and hippocampus undergo plastic changes during development and in response to electric stimulation. It is widely accepted that this process is mediated by insertion and elimination of various glutamate receptors. In a series of recent investigations on left-right asymmetry of hippocampal CA3-CA1 synapses, glutamate receptor subunits have been found to have distinctive expression patterns that depend on the postsynaptic density (PSD area. Particularly notable are the GluR1 AMPA receptor subunit and NR2B NMDA receptor subunit, where receptor density has either a supra-linear (GluR1 AMPA or inverse (NR2B NMDAR relationship to the PSD area. We review current understanding of structural and physiological synaptic plasticity and propose a scheme to classify receptor subtypes by their expression pattern with respect to PSD area.

  10. Effect of linearly polarized light on metamagnetic phase transition in Ca3 Mn2 Ge3O12

    International Nuclear Information System (INIS)

    It has been found that the field H1 of metamagnetic phase transitions in Ca3 Mn2 Ge3O12 garnet changes when the crystal is illuminated with linearly polarized light. The value of H1 decreases under illumination with the light polarization Εparallel [110] and it increases in the case of the light polarization Ε parallel [110]. The difference in the transition fields in these two cases was about 100 Oe at temperature T = 7 K when H1 approx 31,2 k Oe in an unexposed crystal. The change of the field of the metamagnetic phase transition is attributed to the light induction of the magnetic moment whose value and direction depend on polarization of induced light

  11. Site selective spectroscopy and crystal field analysis of Er3+ in Ca3Ga2Ge3O12 garnet

    International Nuclear Information System (INIS)

    A detailed study of the optical spectroscopy of Er3+ in Ca3Ga2Ge3O12 crystals is reported. Several site selective techniques were employed (absorption, luminescence, excitation and up-conversion). The combined use of these techniques allowed the separation and classification of the observed spectral lines. Six different Er3+ optical centres are observed. The energy level analysis was performed using a parametric Hamiltonian for the 4f11 electronic configuration of Er3+ in a D2 symmetry site. A set of parameters was obtained by fitting calculated to experimental energy levels for each identified centre. Differences among centres were analysed and related to the different charge compensating mechanisms. (author)

  12. Effects of Lu and Ni Substitution on Thermoelectric Properties of Ca3Co4O9+δ

    Science.gov (United States)

    Yang, Wenchao; Qian, Haoji; Gan, Jinyu; Wei, Wei; Wang, Zhihe; Tang, Guodong

    2016-06-01

    Effects of (Lu, Ni) co-doping on the thermoelectric properties of Ca3Co4O9+δ (CCO) have been systematically investigated from 20 K to 350 K. The electrical resistivity and thermopower of (Lu, Ni) co-doped samples increase, while their thermal conductivity is significantly depressed as compared to that of pristine CCO. The figure of merit (ZT) of co-doped samples is higher than those of Lu-doped samples and pristine CCO. A maximum ZT of 0.0185 is achieved at 350 K for Ca2.9Lu0.1Co3.9Ni0.1O9+δ . We demonstrate that the simultaneous increase of spin entropy and phonon scattering induced by (Lu, Ni) co-doping boosts ZT of CCO. This study indicates that (Lu, Ni) co-doping may promise an effective way to improve thermoelectric properties of the CCO system.

  13. Flux pinning in Tl1-xCxBa2Ca3Cu4O12-δ superconductor

    International Nuclear Information System (INIS)

    The dissipation mechanism in Tl1-xCxBa2Ca3Cu4O12-δ (x = 0, 0.25, 0.5 and 0.75) superconductor under the influence of external magnetic fields have been studied. The sample with x = 0.25 have shown strong flux pinning characteristic as compared to the Tl1-xCx-1234 (x = 0, 0.5 and 0.75) samples. The scanning electron micrographs of Tl1-xCx-1234 shows well connected grains in x = 0 and 0.25 samples. Whereas, x = 0.5 and 0.75 samples have relatively poor grain morphology, which shows that the source of pinning in Tl0.75C0.25-1234 sample is intrinsic one. The transition width data was also fitted to the thermally activated flux flow model. The apical phonon modes of vibrations were studied through FTIR absorption measurements.

  14. Dendritic cells in lung immunopathology.

    Science.gov (United States)

    Cook, Peter C; MacDonald, Andrew S

    2016-07-01

    Dendritic cells (DCs) lie at the heart of the innate immune system, specialised at recognising danger signals in many forms including foreign material, infection or tissue damage and initiating powerful adaptive immune and inflammatory responses. In barrier sites such as the lung, the instrumental role that DCs play at the interface between the environment and the host places them in a pivotal position in determining the severity of inflammatory disease. The past few years has seen a significant increase in our fundamental understanding of the subsets of DCs involved in pulmonary immunity, as well as the mechanisms by which they are activated and which they may use to coordinate downstream inflammation and pathology. In this review, we will summarise current understanding of the multi-faceted role that DCs play in the induction, maintenance and regulation of lung immunopathology, with an emphasis on allergic pulmonary disease. PMID:27256370

  15. Dendritic Cells for Anomaly Detection

    CERN Document Server

    Greensmith, Julie; Aickelin, Uwe

    2010-01-01

    Artificial immune systems, more specifically the negative selection algorithm, have previously been applied to intrusion detection. The aim of this research is to develop an intrusion detection system based on a novel concept in immunology, the Danger Theory. Dendritic Cells (DCs) are antigen presenting cells and key to the activation of the human signals from the host tissue and correlate these signals with proteins know as antigens. In algorithmic terms, individual DCs perform multi-sensor data fusion based on time-windows. The whole population of DCs asynchronously correlates the fused signals with a secondary data stream. The behaviour of human DCs is abstracted to form the DC Algorithm (DCA), which is implemented using an immune inspired framework, libtissue. This system is used to detect context switching for a basic machine learning dataset and to detect outgoing portscans in real-time. Experimental results show a significant difference between an outgoing portscan and normal traffic.

  16. DEX-1 and DYF-7 establish sensory dendrite length by anchoring dendritic tips during cell migration

    OpenAIRE

    Heiman, Maxwell G.; Shaham, Shai

    2009-01-01

    Cells are devices whose structures delimit function. For example, in the nervous system, neuronal and glial shapes dictate paths of information flow. To understand how cells acquire their shapes, we examined the formation of a sense organ in C. elegans. Using time-lapse imaging, we found that sensory dendrites form by stationary anchoring of dendritic tips during cell-body migration. A genetic screen identified DEX-1 and DYF-7, extracellular proteins required for dendritic tip anchoring, whic...

  17. Effect of acetylcholine receptors on the pain-related electrical activities in the hippocampal CA3 region of morphine-addicted rats

    Directory of Open Access Journals (Sweden)

    Guan Zeng Li

    2015-07-01

    Full Text Available Objective(s:To determine the effect of acetylcholine (ACh, pilocarpine, and atropine on pain evoked responses of pain excited neurons (PEN and pain inhibited neurons (PIN in hippocampal CA3 region of morphine addicted rats. Materials and Methods:Female Wistar rats, weighing between 230-260 g were used in this study. Morphine addicted rats were generated by subcutaneous injection of increasing concentrations of morphine hydrochloride for six days. Trains of electrical impulses applied to the sciatic nerve were used as noxious stimulation and the evoked electrical activities of PEN or PIN in hippocampal CA3 area were recorded using extracellular electrophysiological recording techniques in hippocampal slices. The effect of acetylcholine receptor stimulation byACh, the muscarinic agonist pilocarpine, and the muscarinic antagonist atropine on the pain evoked responses of pain related electrical activities was analyzed in hippocampal CA3 area of morphine addicted rats. Results:Intra-CA3 microinjection of ACh (2 μg/1 μl or pilocarpine (2 μg/1 μl decreased the discharge frequency and prolonged the firing latency of PEN, but increased the discharge frequency and shortened the firing inhibitory duration (ID of PIN. The intra-CA3 administration of atropine (0.5 μg/1 μl produced opposite effect. The peak activity of cholinergic modulators was 2 to 4 min later in morphine addicted rats compared to peak activity previously observed in normal rats. Conclusion: ACh dependent modulation of noxious stimulation exists in hippocampal CA3 area of morphine addicted rats. Morphine treatment may shift the sensitivity of pain related neurons towards a delayed response to muscarinergic neurotransmission in hippocampal CA3 region.

  18. The neuron-astrocyte-microglia triad involvement in neuroinflammaging mechanisms in the CA3 hippocampus of memory-impaired aged rats.

    Science.gov (United States)

    Lana, Daniele; Iovino, Ludovica; Nosi, Daniele; Wenk, Gary L; Giovannini, Maria Grazia

    2016-10-01

    We examined the effects of inflammaging on memory encoding, and qualitative and quantitative modifications on proinflammatory proteins, apoptosis, neurodegeneration and morphological changes of neuron-astrocyte-microglia triads in CA3 Stratum Pyramidale (SP), Stratum Lucidum (SL) and Stratum Radiatum (SR) of young (3months) and aged rats (20months). Aged rats showed short-term memory impairments in the inhibitory avoidance task, increased expression of iNOS and activation of p38MAPK in SP, increase of apoptotic neurons in SP and of ectopic neurons in SL, and decrease of CA3 pyramidal neurons. The number of astrocytes and their branches length decreased in the three CA3 subregions of aged rats, with morphological signs of clasmatodendrosis. Total and activated microglia increased in the three CA3 subregions of aged rats. In aged rats CA3, astrocytes surrounded ectopic degenerating neurons forming "micro scars" around them. Astrocyte branches infiltrated the neuronal cell body, and, together with activated microglia formed "triads". In the triads, significantly more numerous in CA3 SL and SR of aged rats, astrocytes and microglia cooperated in fragmentation and phagocytosis of ectopic neurons. Inflammaging-induced modifications of astrocytes and microglia in CA3 of aged rats may help clearing neuronal debris derived from low-grade inflammation and apoptosis. These events might be common mechanisms underlying many neurodegenerative processes. The frequency to which they appear might depend upon, or might be the cause of, the burden and severity of neurodegeneration. Targeting the triads may represent a therapeutic strategy which may control inflammatory processes and spread of further cellular damage to neighboring cells. PMID:27466072

  19. Dendritic Spine Pathology in Neurodegenerative Diseases.

    Science.gov (United States)

    Herms, Jochen; Dorostkar, Mario M

    2016-05-23

    Substantial progress has been made toward understanding the neuropathology, genetic origins, and epidemiology of neurodegenerative diseases, including Alzheimer's disease; tauopathies, such as frontotemporal dementia; α-synucleinopathies, such as Parkinson's disease or dementia with Lewy bodies; Huntington's disease; and amyotrophic lateral sclerosis with dementia, as well as prion diseases. Recent evidence has implicated dendritic spine dysfunction as an important substrate of the pathogenesis of dementia in these disorders. Dendritic spines are specialized structures, extending from the neuronal processes, on which excitatory synaptic contacts are formed, and the loss of dendritic spines correlates with the loss of synaptic function. We review the literature that has implicated direct or indirect structural alterations at dendritic spines in the pathogenesis of major neurodegenerative diseases, focusing on those that lead to dementias such as Alzheimer's, Parkinson's, and Huntington's diseases, as well as frontotemporal dementia and prion diseases. We stress the importance of in vivo studies in animal models. PMID:26907528

  20. Artificial Dendritic Cells: Multi-faceted Perspectives

    CERN Document Server

    Greensmith, Julie

    2009-01-01

    Dendritic cells are the crime scene investigators of the human immune system. Their function is to correlate potentially anomalous invading entities with observed damage to the body. The detection of such invaders by dendritic cells results in the activation of the adaptive immune system, eventually leading to the removal of the invader from the host body. This mechanism has provided inspiration for the development of a novel bio-inspired algorithm, the Dendritic Cell Algorithm. This algorithm processes information at multiple levels of resolution, resulting in the creation of information granules of variable structure. In this chapter we examine the multi-faceted nature of immunology and how research in this field has shaped the function of the resulting Dendritic Cell Algorithm. A brief overview of the algorithm is given in combination with the details of the processes used for its development. The chapter is concluded with a discussion of the parallels between our understanding of the human immune system a...

  1. Two-port laparoscopic cholecystectomy with modified suture retraction of the fundus: A practical approach

    Directory of Open Access Journals (Sweden)

    Ming G Tian

    2013-01-01

    Full Text Available Context: Although transumbilical single incision laparoscopic cholecystectomy (SILC has been demonstrated to be superior cosmetic, it is only limited to simple cases at present. In complex cases, the standard four- or three-port LC is still the treatment of choice. Aim: To summarize the clinical effect of a modified technique in two-port LC. Settings and Design: A consecutive series of patients with benign gallbladder diseases admitted to the provincial teaching hospital who underwent LC in the past 4 years were included. A modified two-port LC was the first choice except for those requiring laparoscopic common bile duct exploration (LCBDE. Materials and Methods: The operation was done with suture retraction of the fundus by a needle-like retractor. The patients′ data, including the operative time, time consumed by gallbladder retraction, operative bleeding, conversion rate, rate of adding trocars, and postoperative complications were recorded. Statistical Analysis: Data were expressed as percentage and mean with standard deviation. Results: Total 107 patients with chronic calculous cholecystitis (N = 61, acute calculous cholecystitis (N = 43, and cholecystic polyps (N = 3 received two-port LC. The procedure was successful in 99 out of 107 cases (success rate, 92.5%, and a third trocar was added in the remaining 8 cases (7.5% due to severe pathological changes. The operative time was 47.2 (±13.21 min. There was no conversion to open surgery. Conclusion: Two-port LC using a needle-like retractor for suture retraction of the gallbladder fundus is a practical approach when considering the safety, convenience, and indications as well as relatively minimal invasion.

  2. Comparative photoelastic study of dental and skeletal anchorages in the canine retraction

    Directory of Open Access Journals (Sweden)

    Cristiane Aparecida de Assis Claro

    2014-01-01

    Full Text Available OBJECTIVE: To compare dental and skeletal anchorages in mandibular canine retraction by means of a stress distribution analysis. METHODS: A photoelastic model was produced from second molar to canine, without the first premolar, and mandibular canine retraction was simulated by a rubber band tied to two types of anchorage: dental anchorage, in the first molar attached to adjacent teeth, and skeletal anchorage with a hook simulating the mini-implant. The forces were applied 10 times and observed in a circular polariscope. The stresses located in the mandibular canine were recorded in 7 regions. The Mann-Whitney test was employed to compare the stress in each region and between both anchorage systems. The stresses in the mandibular canine periradicular regions were compared by the Kruskal-Wallis test. RESULTS: Stresses were similar in the cervical region and the middle third. In the apical third, the stresses associated with skeletal anchorage were higher than the stresses associated with dental anchorage. The results of the Kruskal-Wallis test showed that the highest stresses were identified in the cervical-distal, apical-distal, and apex regions with the use of dental anchorage, and in the apical-distal, apical-mesial, cervical-distal, and apex regions with the use of skeletal anchorage. CONCLUSIONS: The use of skeletal anchorage in canine retraction caused greater stress in the apical third than the use of dental anchorage, which indicates an intrusive component resulting from the direction of the force due to the position of the mini-implant and the bracket hook of the canine.

  3. RETRACTED: Auricular prosthesis fabrication using computer-aided design and rapid prototyping technologies.

    Science.gov (United States)

    Shah, Mayank

    2016-06-01

    At the request of the editorMayank Shah 'Auricular prosthesis fabrication using computer-aided design and rapid prototyping technologies' Prosthetics and Orthotics International, published online before print on October 8, 2013 as doi:10.1177/0309364613504779has been retracted. This is because it contains unattributed overlap withK. Subburaj, C. Nair, S. Rajesh, S. M. Meshram, B. Ravi 'Rapid development of auricular prosthesis using CAD and rapid prototyping technologies' International Journal of Oral & Maxillofacial Surgery 2007; 36: 938-943 doi:10.1016/j.ijom.2007.07.013. PMID:24104058

  4. Buckling-induced retraction of spherical shells: A study on the shape of aperture

    Science.gov (United States)

    Lin, Sen; Xie, Yi Min; Li, Qing; Huang, Xiaodong; Zhou, Shiwei

    2015-06-01

    Buckling of soft matter is ubiquitous in nature and has attracted increasing interest recently. This paper studies the retractile behaviors of a spherical shell perforated by sophisticated apertures, attributed to the buckling-induced large deformation. The buckling patterns observed in experiments were reproduced in computational modeling by imposing velocity-controlled loads and eigenmode-affine geometric imperfection. It was found that the buckling behaviors were topologically sensitive with respect to the shape of dimple (aperture). The shell with rounded-square apertures had the maximal volume retraction ratio as well as the lowest energy consumption. An effective experimental procedure was established and the simulation results were validated in this study.

  5. Microendoscopic Removal of Deep-Seated Brain Tumors Using Tubular Retraction System.

    Science.gov (United States)

    Ratre, Shailendra; Yadav, Yad Ram; Parihar, Vijay Singh; Kher, Yatin

    2016-07-01

    Background Retraction of the overlying brain can be difficult without causing significant trauma when using traditional brain retractors with blades. These retractors may produce focal pressure and may result in brain contusion or infarction. Tubular retractors offer the advantage of low retracting pressure that is less likely to be traumatic. Low retraction pressure in the tubular retractor is due to the distribution of retraction force in all directions in a larger area. Material and Methods We conducted a retrospective study of 100 patients with deep-seated tumors operated on from January 2010 to December 2014. Tumor removal was accomplished with the help of a microscope and/or endoscope. Tubular brain retractors sizes 23, 18, and 15 mm were used. Folding of the tubular retractor after making a longitudinal cut allowed a small corticectomy. Larger retractor sizes were used in the earlier part of the study and in larger tumors. All the patients were evaluated postoperatively by computed tomography scan on the first postoperative day, and subsequent scans were done as and when needed. Any brain contusion or infarctions and the amount of tumor removal were recorded. Results A total of 74 patients had astrocytomas; 12, meningiomas; 4, colloid cyst of the third ventricle; 4, metastases; 4, primitive neuroectodermal tumor; 1, neurocytoma; and 1, ependymoma. Pure endoscopic excision without using a microscope was performed in 12 patients. Lesions were in the frontal (n = 34), parietal (n = 22), intraventricular (n = 16), basal ganglion or thalamic (n = 14), occipital (n = 10), and cerebellar (n = 4) areas. Total, near-total, and partial excision was achieved in 49, 29, and 22 patients, respectively. Use of a conventional retractor for excision of peripheral and superficial parts of a large tumor, small brain contusions, and technical failure were observed in 7, 4, and 1 patient, respectively. The low incidence of contusion may be partly

  6. Theoretical modelling of wakes from retractable flapping wings in forward flight.

    Science.gov (United States)

    Parslew, Ben; Crowther, William J

    2013-01-01

    A free-wake method is used to simulate the wake from retractable, jointed wings. The method serves to complement existing experimental studies that visualise flying animal wakes. Simulated wakes are shown to be numerically convergent for a case study of the Rock Pigeon in minimum power cruising flight. The free-wake model is robust in simulating wakes for a range of wing geometries and dynamics without requiring changes to the numerical method. The method is found to be useful for providing low order predictions of wake geometries. However, it is not well suited to reconstructing 3d flowfields as solutions are sensitive to the numerical mesh node locations. PMID:23882442

  7. Theoretical modelling of wakes from retractable flapping wings in forward flight

    Directory of Open Access Journals (Sweden)

    Ben Parslew

    2013-07-01

    Full Text Available A free-wake method is used to simulate the wake from retractable, jointed wings. The method serves to complement existing experimental studies that visualise flying animal wakes. Simulated wakes are shown to be numerically convergent for a case study of the Rock Pigeon in minimum power cruising flight. The free-wake model is robust in simulating wakes for a range of wing geometries and dynamics without requiring changes to the numerical method. The method is found to be useful for providing low order predictions of wake geometries. However, it is not well suited to reconstructing 3d flowfields as solutions are sensitive to the numerical mesh node locations.

  8. Retracted article: Flexible Fourier Stationary Test in GDP per capita for Central Eastern European Countries

    Directory of Open Access Journals (Sweden)

    Meng-Nan Zhu

    2011-06-01

    Full Text Available Statement of Retraction (http://www.efri.uniri.hr/prikaz.asp?txt_id=7366 This is to notify our respectful reading public that the Editorial Board of the journal Zbornik radova Ekonomskog fakulteta u Rijeci, časopis za ekonomsku teoriju i praksu/ Proceedings of Rijeka Faculty of Economics, Journal of Economics and Business has retracted the following article from publication: “Flexible Fourier Stationary Test in GDP per capita for Central Eastern European Countries“, by Hsu-Ling Chang, Chi-Wei Su, Meng-Nan Zhu, published in our journal Zbornik radova Ekonomskog fakulteta u Rijeci, časopis za ekonomsku teoriju i praksu/ Proceedings of Rijeka Faculty of Economics, Journal of Economics and Business, 2011, vol. 29 (1, pp. 51-63 and almost concurrently published in the journal Eastern European Economics, 2011, vol. 49 (3, pp. 54-65. Being in contact with Josef C Brada, Professor Emeritus, Editor of the journal Eastern European Economics (EEE, we realized that the paper had been sent to both journals, although first published in the EEE and then in our Journal. According to professor Brada’s and our analysis, the paper published in these two journals is exactly the same, except for minor differences in wording, most likely due to editing the text before publication. The outstanding differences are in the title and the fact that the paper published in our Journal has three authors and in EEE journal has two. Whatsoever, owing to the fact that the article had been sent to both journals almost at the same time, it had been impossible to find out the case during the review procedure. Due to this unpleasant situation, our Editorial Board would like to inform our valuable readers that all the necessary measures to retract the paper from our publication have been undertaken and according to publishing ethical principles, cooperation with the authors of the retracted paper have been stopped. Although, in this case neither EEE nor our Journal had any

  9. OPTIMAL ALGORITHM FOR NO TOOlRETRACTIONS CONTOUR-PARALLEL OFFSET TOOL-PATH LINKING

    Institute of Scientific and Technical Information of China (English)

    HAO Yongtao; JIANG Lili

    2007-01-01

    A contour-parallel offset (CPO) tool-path linking algorithm is derived without toolretractions and with the largest practicability. The concept of "tool-path loop tree" (TPL-tree)providing the information on the parent/child relationships among the tool-path loops (TPLs) is presented. The direction, tool-path loop, leaf/branch, layer number, and the corresponding points of the TPL-tree are introduced. By defining TPL as a vector, and by traveling throughout the tree, a CPO tool-path without tool-retractions can be derived.

  10. Interfacial tension of PBT/SAN blends by the drop retraction method

    OpenAIRE

    Edson Noriyuki Ito; Marcelo Massayoshi Ueki; Rosario Elida Suman Bretas; Elias Hage Junior

    2008-01-01

    The aim of this work was to evaluate the interfacial tension from the poly(butylene terephtalate) and poly(styrene-co-acrylonitrile) (PBT/SAN) interface region using the drop retraction method. SAN filaments were sandwiched between two PBT films; the whole system was heated up to 240 °C, in a hot stage coupled to an optical microscope. The rheological parameters of the PBT/SAN system were obtained by parallel plates rheometry. An increase of the interfacial tension with the PBT molecular weig...

  11. Rotating and retractable lighting device for a swimming pool containing radioactive materials

    International Nuclear Information System (INIS)

    The lighting device is retractable under the action of appliances working in the swimming pool or thanks to various impacts. Each arm is assembled pivoting around a vertical axis. Return means as spring allow to bring back in a balanced angular position the arm carrying a headlight in a determined angular position after the arm and the headlight having been spread from this position in an intentional or fortuitous way. Application to lighting devices for nuclear reactor swimming pools. (Author). 4 figs., 3 refs

  12. Free energy and dendritic self-organisation

    Directory of Open Access Journals (Sweden)

    Stefan J Kiebel

    2011-10-01

    Full Text Available In this paper, we pursue recent observations that, through selective dendritic filtering, single neurons respond to specific sequences of presynaptic inputs. We try to provide a principled and mechanistic account of this selectivity by applying the free energy principle to a dendrite that is immersed in its neuropil or environment. We assume that neurons self-organize to minimise a free energy bound on the self-information or surprise of presynaptic inputs that are sampled. We model this as a selective pruning of dendritic spines that are expressed on a dendritic branch. This pruning occurs when the optimized postsynaptic gain falls below a threshold. Crucially, postsynaptic gain is itself optimized with respect to free energy. Pruning suppresses free energy as the dendrite selects presynaptic signals that conform to its expectations, specified by a generative model implicit in its intracellular kinetics. Not only does this provide a principled account of how neurons organize and selectively sample the myriad of potential presynaptic inputs they are exposed to, but it also connects the optimization of elemental neuronal (dendritic processing to generic (surprise or evidence-based schemes in statistics and machine learning, such as Bayesian model selection and automatic relevance determination.

  13. Evaluation of Ca3(Co,M2O6 (M=Co, Fe, Mn, Ni as new cathode materials for solid-oxide fuel cells

    Directory of Open Access Journals (Sweden)

    Fushao Li

    2015-10-01

    Full Text Available Series compounds Ca3(Co0.9M0.12O6 (M=Co, Fe, Mn, Ni with hexagonal crystal structure were prepared by sol–gel route as the cathode materials for solid oxide fuel cells (SOFCs. Effects of the varied atomic compositions on the structure, electrical conductivity, thermal expansion and electrochemical performance were systematically evaluated. Experimental results showed that the lattice parameters of Ca3(Co0.9Fe0.12O6 and Ca3(Co0.9Mn0.12O6 were both expanded to certain degree. Electron-doping and hole-doping effects were expected in Ca3(Co0.9Mn0.12O6 and Ca3(Co0.9Ni0.12O6 respectively according to the chemical states of constituent elements and thermal-activated behavior of electrical conductivity. Thermal expansion coefficients (TEC of Ca3(Co0.9M0.12O6 were measured to be distributed around 16×10−6 K−1, and compositional elements of Fe, Mn, and Ni were especially beneficial for alleviation of the thermal expansion problem of cathode materials. By using Ca3(Co0.9M0.12O6 as the cathodes operated at 800 °C, the interfacial area-specific resistance varied in the order of M=CoCa3(Co0.9Fe0.12O6 showed the best electrochemical performance and the power density as high as ca. 500 mW cm−2 at 800 °C achieved in the single cell with La0.8Sr0.2Ga0.83Mg0.17O2.815 as electrolyte and Ni–Ce0.8Sm0.2O1.9 as anode. Ca3(Co0.9M0.12O6 (M=Co, Fe, Mn, Ni can be used as the cost-effective cathode materials for SOFCs.

  14. Adolescent mice show anxiety- and aggressive-like behavior and the reduction of long-term potentiation in mossy fiber-CA3 synapses after neonatal maternal separation.

    Science.gov (United States)

    Shin, S Y; Han, S H; Woo, R-S; Jang, S H; Min, S S

    2016-03-01

    Exposure to maternal separation (MS) during early life is an identified risk factor for emotional disorders such as anxiety and depression later in life. This study investigated the effects of neonatal MS on the behavior and long-term potentiation (LTP) as well as basic synaptic transmission at hippocampal CA3-CA1 and mossy fiber (MF)-CA3 synapses in adolescent mice for 19days. When mice were adolescents, we measured depression, learning, memory, anxious and aggressive behavior using the forced swimming test (FST), Y-maze, Morris water maze (MWM), elevated plus maze (EPM), three consecutive days of the open field test, the social interaction test, the tube-dominance test and the resident-intruder test. The results showed that there was no difference in FST, Y-maze, and MWM performance. However, MS mice showed more anxiety-like behavior in the EPM test and aggressive-like behavior in the tube-dominance and resident-intruder tests. In addition, the magnitude of LTP and release probability in the MF-CA3 synapses was reduced in the MS group but not in the CA3-CA1 synapse. Our results indicate that early life stress due to MS may induce anxiety- and aggressive-like behavior during adolescence, and these effects are associated with synaptic plasticity at the hippocampal MF-CA3 synapses. PMID:26733385

  15. Mechanoluminescence, thermoluminescence, photoluminescence studies on Ca3 Y2 Si3 O12 :RE(3+) (RE(3+) = Dy(3+) and Eu(3+) ) phosphors.

    Science.gov (United States)

    Kadukar, Monali R; Yawalkar, P W; Choithrani, Renu; Dhoble, S J

    2015-12-01

    Dy(3+) and Eu(3+) activated Ca3 Y2 Si3 O12 phosphors were synthesized by the solid-state synthesis method. The phosphors were characterized by X-ray diffraction (XRD), mechanoluminescence (ML), thermoluminescence (TL) and photoluminescence (PL) to determine structure and luminescence. For ML glow curves, only one peak was observed, as only one type of luminescence centre was formed during irradiation. The Ca3 Y2 Si3 O12 :Dy(3+) TL glow curve showed a single peak at 151.55°C and the Ca3 Y2 Si3 O12 :Eu(3+) TL glow curve peaked at 323°C with a small peak at 192°C, indicating that two types of traps were activated. The trapping parameters for both the samples were calculated using Chen's peak shape method. Dy(3+) -activated Ca3 Y2 Si3 O12 showed emission at 482 and 574 nm when excited by a 351 nm excitation wavelength, whereas the Eu(3+) -activated Ca3 Y2 Si3 O12 phosphor PL emission spectra showed emission peaks at 613 nm, 591 nm, 580 nm when excited at 395 nm wavelength. When excited at 466 nm, prominent emission peaks were observed at their respective positions with very slight shifts. Copyright © 2015 John Wiley & Sons, Ltd. PMID:25807925

  16. Velocity of Canine Retraction in Angle Class I Treated with First Premolar Extraction: Effect of Facial Pattern.

    Science.gov (United States)

    Nakamura, Yu; Toyodome, Yoriko; Ishii, Takenobu; Sakamoto, Teruo; Motegi, Etsuko; Sueishi, Kenji

    2015-01-01

    Recently, new methods have been applied to increase velocity of tooth movement. A standard mean of tooth movement velocity remains to be established, however. Moreover, to our knowledge, no studies have investigated the effect of factors affecting this velocity. The aim of the present study was to investigate the effect of facial pattern on the mean velocity of canine retraction in selected cases of orthodontic treatment carried out at this hospital. A total of 112 patients with Angle Class I crowding treated with extraction of the bilateral maxillary and mandibular first premolars and a conventional edgewise bracket were selected at random. The canine retraction period was defined as that between the end of leveling and the beginning of anterior retraction, and was obtained from medical records. Calipers were used to measure how far the canine cusps moved between pre- and post-surgically on superimposed cephalometric tracings. The velocity of canine retraction was significantly slower in the maxilla of male patients with a brachyofacial pattern (p<0.01). Canine retraction is the longest stage of orthodontic treatment. Here, movement was slowest in the maxilla of male patients with a brachyofacial pattern. This indicates that treatment may take longer than average in male patients with a brachyofacial pattern, and that this should be explained prior to commencing such work. PMID:26370574

  17. Drosophila motor neuron retraction during metamorphosis is mediated by inputs from TGF-β/BMP signaling and orphan nuclear receptors.

    Directory of Open Access Journals (Sweden)

    Ana Boulanger

    Full Text Available Larval motor neurons remodel during Drosophila neuro-muscular junction dismantling at metamorphosis. In this study, we describe the motor neuron retraction as opposed to degeneration based on the early disappearance of β-Spectrin and the continuing presence of Tubulin. By blocking cell dynamics with a dominant-negative form of Dynamin, we show that phagocytes have a key role in this process. Importantly, we show the presence of peripheral glial cells close to the neuro-muscular junction that retracts before the motor neuron. We show also that in muscle, expression of EcR-B1 encoding the steroid hormone receptor required for postsynaptic dismantling, is under the control of the ftz-f1/Hr39 orphan nuclear receptor pathway but not the TGF-β signaling pathway. In the motor neuron, activation of EcR-B1 expression by the two parallel pathways (TGF-β signaling and nuclear receptor triggers axon retraction. We propose that a signal from a TGF-β family ligand is produced by the dismantling muscle (postsynapse compartment and received by the motor neuron (presynaptic compartment resulting in motor neuron retraction. The requirement of the two pathways in the motor neuron provides a molecular explanation for the instructive role of the postsynapse degradation on motor neuron retraction. This mechanism insures the temporality of the two processes and prevents motor neuron pruning before postsynaptic degradation.

  18. Effect of botulinum toxin for eyelid retraction in dysthyroid ophthalmopathy as related to hypertrophy of intraorbital muscles

    International Nuclear Information System (INIS)

    The purpose of this study was to report the effect of botulinum toxin for eyelid retraction in dysthyroid ophthalmopathy with or without hypertrophy of intraorbital muscles. We reviewed 28 eyes of 23 cases who received injection of botulinum toxin for eyelid retraction. Eyelid retraction improved in 23 eyes (82%). The height of palpebral fissure ranged from 8 to 12 mm, average 10.8 mm, before treatment. It ranged from 5 to 12 mm, average 9.4 mm, 2 weeks after treatment. The difference was significant. By magnetic resonance imaging (MRI), hypertrophy of levator and/or superior rectus muscle was present in 19 eyes and absent in 9 eyes. Eyelid retraction improved in 2 eyes (11%) in the former group and in one eye (11%) in the latter. Dalrymple sign was present in 28 eyes before and disappeared in 14 eyes after treatment. Graefe sign was present in 28 eyes before and disappeared in one eye after treatment. Botulinum toxin is effective for eyelid retraction and not for Graefe sign in dysthyroid ophthalmopathy. (author)

  19. First-principles study of the electronic and magnetic structures of the tetragonal and orthorhombic phases of Ca3Mn2O7

    Science.gov (United States)

    Matar, S. F.; Eyert, V.; Villesuzanne, A.; Whangbo, M.-H.

    2007-08-01

    On the basis of density functional theory electronic band structure calculations using the augmented spherical wave method, the electronic and magnetic properties of the orthorhombic and tetragonal phases of Ca3Mn2O7 were investigated and the spin exchange interactions of the orthorhombic phase were analyzed. Our calculations show that the magnetic insulating states are more stable than the nonmagnetic metallic state for both polymorphs of Ca3Mn2O7 , the orthorhombic phase is more stable than the tetragonal phase, and the ground state of the orthorhombic phase is antiferromagnetic. The total energies calculated for the three spin states of the orthorhombic phase of Ca3Mn2O7 led to estimates of the spin exchange interactions Jnn=-3.36meV and Jnnn=-0.06meV . The accuracy of these estimates was tested by calculating the Curie-Weiss temperature within the mean-field approximation.

  20. Polarized spectra calculation and continuous wave laser operation of Yb-doped disordered Ca3La2(BO3)4 crystal

    Science.gov (United States)

    Wang, Yeqing; Chen, Aixi; You, Zhenyu; Tu, Chaoyang

    2015-12-01

    A notable disorder crystal Yb:Ca3La2(BO3)4 crystal with Yb3+ ion doping concentration of 10 at.% was grown by the Czochralski method. The polarized absorption, polarized emission, and polarized gain cross sections were systematically calculated. The laser operations were investigated with Yb:Ca3La2(BO3)4 crystals cut along the a, b, and c crystallographic axes. The highest output power of 3.88 W was obtained by using the b-cut Yb:Ca3La2(BO3)4 crystal, with a slope efficiency of 62%. Additionally, it was confirmed that the output laser spectra were largely dependent on the output coupler.

  1. Phases of variable composition in the Ca3(VO4)2-NdVO4 - Na3VO4 system

    International Nuclear Information System (INIS)

    Phase equilibriums in the Ca3(VO4)2 - NdVO4-Na3VO4 system are studied. Formation of variable composition phases on the base of calcium orthovanadate is established. The field of variable composition phase is placed inside of Ca3(VO4)2 - Ca9Nd□(VO4)7 - Ca10Na(VO4)7 - Ca8NdNa2(VO4)7 (Z = 6) quadrangle. Boundary compositions are determined by structure of low temperature modification of Ca3(VO4)2 (Z = 21, sp. gr. R3c). The degree of Ca(4) positions occupancy has influence on phase transition temperature, ionic conductivity and parameters of IR- and CS-spectra. Considerable growth of the conductivity higher than 650 K on the calcium ions is explained by order-disorder transformation associated with disproportional of structural vacancies (□) on different cation positions

  2. Effect of atomic disorder and Ce doping on superconductivity of Ca3Rh4Sn13 : Electric transport properties under high pressure

    Science.gov (United States)

    Ślebarski, A.; Goraus, J.; Maśka, M. M.; Witas, P.; Fijałkowski, M.; Wolowiec, C. T.; Fang, Y.; Maple, M. B.

    2016-06-01

    We report the observation of a superconducting state below ˜8 K coexistent with a spin-glass state caused by atomic disorder in Ce substituted Ca3Rh4Sn13 . Measurements of specific heat, resistivity, and magnetism reveal the existence of inhomogeneous superconductivity in samples doped with Ce with superconducting critical temperatures Tc higher than those observed in the parent compound. For Ca3Rh4Sn13 , the negative value of the change in resistivity ρ with pressure P , d ρ /d P correlates well with the calculated decrease in the density of states (DOS) at the Fermi energy with P . Based on band-structure calculations performed under pressure, we demonstrate how the change in DOS would affect Tc of Ca3Rh4Sn13 under negative lattice pressure in samples that are strongly defected by quenching.

  3. Formation of dendritic metallic nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Ranjan, Nitesh; Mertig, Michael [Institute for Materials Science, Max Bergmann Center of Biomaterials, Dresden University of Technology, D-01062 Dresden (Germany); Vinzelberg, Hartmut [IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany)

    2009-07-01

    Recently, we reported an electrical-field-controlled growth process for the directed bottom-up assembly of one-dimensional palladium nanowires between micro-fabricated electrodes. The wires, grown from an aqueous palladium salt solution by dielectrophoresis, had a thickness of only 5-10 nm and a length of up to several micrometers. The growth process was found to depend largely on the deposition conditions like the strength and the frequency of the applied AC field and the concentration of the metal salt solution. Here, we report the formation of thin, but straight and dendritic metallic nanowires, obtained in the low-frequency regime. The morphology of the wires was characterized by scanning force microscopy (SFM), scanning electron microscopy and transmission electron microscopy. SFM investigations revealed that the palladium nanowires grown over the glass and silicon substrates have a typical thickness of about 25 nm. Room temperature I-V measurements show them to be Ohmic in nature with a resistance of about 80 kOhm. Low-temperature measurements show the phenomenon of zero bias anomaly. The investigated growth method is capable of controllable in-place formation of complex circuit patterns for future nanoelectronics.

  4. Fully three-dimensional reconstruction for a PET camera with retractable septa

    International Nuclear Information System (INIS)

    This paper reports on a fully 3-D reconstruction algorithm developed to reconstruct data from a sixteen-ring PET camera (a Siemens/CTI 953B) with automatically retractable septa. The tomograph is able to acquire coincidences between any pair of detector rings and septa retraction increases the total system count rate by a factor of 7.8 (including scatter) and 4.7 (scatter subtracted) for a uniform, 20 cm diameter cylinder. The reconstruction algorithm is based on 3-D filtered backprojection, expressed in a form suitable for the multi-angle sinogram data. Sinograms which are not measured due to the truncated cylindrical geometry of the tomograph, but which are required for a spatially-invariant response function, are obtained by forward projection. After filtering, the complete set of sinograms is backprojected into a 3-D volume of 128 x 128 x 31 voxels using a voxel-driven procedure. The algorithm has been validated with simulation, and tested with both phantom and clinical data from the 953B

  5. Vision Therapy for Convergence Insufficiency Co-Incident with Duane Retraction Syndrome

    Directory of Open Access Journals (Sweden)

    Tonya Tira, OD

    2014-03-01

    Full Text Available Background: Duane retraction syndrome (DRS is a congenital ocular motility disorder characterized by limited abduction and/or limited adduction, globe retraction, and narrowing of the palpebral fissure on adduction. Because of adduction limits, these patients may also exhibit convergence insufficiency (CI. Symptomatic individuals can often benefit from optometric vision therapy (OVT. Although OVT does not treat the DRS itself, these procedural interventions can alleviate symptoms by improving vergence and accommodative ability. Case: A 10-year-old girl was referred for complaints of asthenopia at near and intermittent horizontal diplopia on side gaze. She exhibited signs of intermittent alternating exotropia at near and poor pursuit eye movements. A visual skills evaluation revealed DRS and CI; with the latter being managed successfully with OVT. Symptoms were relieved entirely with a relatively short course of therapy for the CI, despite the presence of adduction limitations due to congenital miswiring of the lateral rectus. Conclusion: Optometric vision therapy is not a common treatment consideration for patients with DRS, but underlying binocular vision anomalies may cause some of these patients to be symptomatic. Appropriate testing should be performed to reveal these visual skills deficits and referrals should be made for OVT when indicated. It is important to understand that a disease or pathological state can have one or more associated functional overlays that can be successfully treated with a resultant improved quality of life.

  6. Effect of intrusive and retraction forces in labial and lingual orthodontics: A finite element study

    Directory of Open Access Journals (Sweden)

    Rohan Mascarenhas

    2014-01-01

    Full Text Available Objectives: Lingual orthodontics differs in biomechanics as compared to labial system and has biomechanical advantages. Although theoretical approaches have explained the differences between labial and lingual orthodontics, the finite element method (FEM may be better suited to analyze these differences. This study analyzes the effect of vertical and horizontal forces together on the tooth using FEM. Materials and Methods: An extracted right maxillary central incisor was radiographed and was used to create a solid model using ANSYS. The geometric model was converted into a finite element model with the help of ANSYS software. The model consists of 27,000 elements and 30,000 nodes. Two force vectors (vertical and horizontal were applied labially and lingually at 3 different heights- 4 mm, 5 mm and 6 mm from the incisal edge. Results: In the labial system, the net force vector passes through the center of resistance (CR and brings about intrusion. The net force vector in lingual orthodontics does not pass through the center of resistance and produces lingual tipping of the incisors. Conclusion: Intrusion and retraction forces bring about tipping of incisors in lingual orthodontics. The same amount of intrusion and retraction forces brings about intrusion of incisors in labial orthodontics. Therefore, direction and amount of forces should be carefully and judiciously applied after taking into consideration the resultant biomechanical differences.

  7. Improved Geometry of Decellularized Tissue Engineered Heart Valves to Prevent Leaflet Retraction.

    Science.gov (United States)

    Sanders, Bart; Loerakker, Sandra; Fioretta, Emanuela S; Bax, Dave J P; Driessen-Mol, Anita; Hoerstrup, Simon P; Baaijens, Frank P T

    2016-04-01

    Recent studies on decellularized tissue engineered heart valves (DTEHVs) showed rapid host cell repopulation and increased valvular insufficiency developing over time, associated with leaflet shortening. A possible explanation for this result was found using computational simulations, which revealed radial leaflet compression in the original valvular geometry when subjected to physiological pressure conditions. Therefore, an improved geometry was suggested to enable radial leaflet extension to counteract for host cell mediated retraction. In this study, we propose a solution to impose this new geometry by using a constraining bioreactor insert during culture. Human cell based DTEHVs (n = 5) were produced as such, resulting in an enlarged coaptation area and profound belly curvature. Extracellular matrix was homogeneously distributed, with circumferential collagen alignment in the coaptation region and global tissue anisotropy. Based on in vitro functionality experiments, these DTEHVs showed competent hydrodynamic functionality under physiological pulmonary conditions and were fatigue resistant, with stable functionality up to 16 weeks in vivo simulation. Based on implemented mechanical data, our computational models revealed a considerable decrease in radial tissue compression with the obtained geometrical adjustments. Therefore, these improved DTEHV are expected to be less prone to host cell mediated leaflet retraction and will remain competent after implantation. PMID:26183964

  8. Drive system for the retraction/extension of variable diameter rotor systems

    Science.gov (United States)

    Gmirya, Yuriy (Inventor)

    2003-01-01

    A drive system for a variable diameter rotor (VDR) system includes a plurality of rotor blade assemblies with inner and outer rotor blade segments. The outer blade segment being telescopically mounted to the inner blade segment. The VDR retraction/extension system includes a drive housing mounted at the root of each blade. The housing supports a spool assembly, a harmonic gear set and an electric motor. The spool assembly includes a pair of counter rotating spools each of which drive a respective cable which extends through the interior of the inboard rotor blade section and around a pulley mounted to the outboard rotor blade section. In operation, the electric motor drives the harmonic gear set which rotates the counter rotating spools. Rotation of the spools causes the cables to be wound onto or off their respective spool consequently effecting retraction/extension of the pulley and the attached outboard rotor blade section relative the inboard rotor blade section. As each blade drive system is independently driven by a separate electrical motor, each independent VDR blade assembly is independently positionable.

  9. Inhibition of the K+ channel K(Ca3.1 reduces TGF-β1-induced premature senescence, myofibroblast phenotype transition and proliferation of mesangial cells.

    Directory of Open Access Journals (Sweden)

    Rong-Guo Fu

    Full Text Available OBJECTIVE: K(Ca3.1 channel participates in many important cellular functions. This study planned to investigate the potential involvement of K(Ca3.1 channel in premature senescence, myofibroblast phenotype transition and proliferation of mesangial cells. METHODS & MATERIALS: Rat mesangial cells were cultured together with TGF-β1 (2 ng/ml and TGF-β1 (2 ng/ml + TRAM-34 (16 nM separately for specified times from 0 min to 60 min. The cells without treatment served as controls. The location of K(Ca3.1 channels in mesangial cells was determined with Confocal laser microscope, the cell cycle of mesangial cells was assessed with flow cytometry, the protein and mRNA expression of K(Ca3.1, α-smooth muscle actin (α-SMA and fibroblast-specific protein-1 (FSP-1 were detected with Western blot and RT-PCR. One-way analysis of variance (ANOVA and Student-Newman-Keuls-q test (SNK-q were used to do statistical analysis. Statistical significance was considered at P<0.05. RESULTS: Kca3.1 channels were located in the cell membranes and/or in the cytoplasm of mesangial cells. The percentage of cells in G0-G1 phase and the expression of K(ca3.1, α-SMA and FSP-1 were elevated under the induction of TGF-β1 when compared to the control and decreased under the induction of TGF-β1+TRAM-34 when compared to the TGF-β1 induced (P<0.05 or P<0.01. CONCLUSION: Targeted disruption of K(Ca3.1 inhibits TGF-β1-induced premature aging, myofibroblast-like phenotype transdifferentiation and proliferation of mesangial cells.

  10. Non-aqueous synthesis of water-dispersible Fe3O4-Ca3(PO4)2 core-shell nanoparticles

    International Nuclear Information System (INIS)

    The Fe3O4-Ca3(PO4)2 core-shell nanoparticles were prepared by one-pot non-aqueous nanoemulsion with the assistance of a biocompatible triblock copolymer, poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEO-PPO-PEO), integrating the magnetic properties of Fe3O4 and the bioactive functions of Ca3(PO4)2 into single entities. The Fe3O4 nanoparticles were pre-formed first by thermal reduction of Fe(acac)3 and then the Ca3(PO4)2 layer was coated by simultaneous deposition of Ca2+ and PO43-. The characterization shows that the combination of the two materials into a core-shell nanostructure retains the magnetic properties and the Ca3(PO4)2 shell forms an hcp phase (a = 7.490 A, c = 9.534 A) on the Fe3O4 surface. The magnetic hysteresis curves of the nanoparticles were further elucidated by the Langevin equation, giving an estimation of the effective magnetic dimension of the nanoparticles and reflecting the enhanced susceptibility response as a result of the surface covering. Fourier transform infrared (FTIR) analysis provides the characteristic vibrations of Ca3(PO4)2 and the presence of the polymer surfactant on the nanoparticle surface. Moreover, the nanoparticles could be directly transferred to water and the aqueous dispersion-collection process of the nanoparticles was demonstrated for application readiness of such core-shell nanostructures in an aqueous medium. Thus, the construction of Fe3O4 and Ca3(PO4)2 in the core-shell nanostructure has conspicuously led to enhanced performance and multi-functionalities, offering various possible applications of the nanoparticles.

  11. Electronic Structure and Thermoelectric Properties of Na and Ni-doped Ca3Co2O6

    Institute of Scientific and Technical Information of China (English)

    MIN Xinmin; YANG Wen

    2006-01-01

    The electronic structures of Ca3Co2O6, Na and Ni doped models were studied by the quantum chemical software of Cambride Serial Total Energy Package (CASTEP) that is based on density function theory (DFT) and pseudo-potential. The electronic conductivity, seebeck coefficient, thermal conductivity and figure of merit (Z) were computed. The energy band structure reveals the form of the impurity levels due to the substitutional impurity in semiconductors. Na-doped model shows the character of p-type semiconductor, but Ni-doped model is n-type semiconductor. The calculation results show that the electric conductivity of the doped model is higher than that of the non-doped model, while the Seebeck coefficient and thermal conductivity of the doped model are lower than those of the non-doped one. Because of the great increase of the electric conductivity, Z of Na-doped model is enhanced and thermoelectric properties are improved. On the other hand, as the large decline of Seebeck coefficient, Z of Ni-doped model is less than that of the non-doped model.

  12. Intrinsic Josephson properties in (Hg, Re)Ba2Ca3Cu4O10+δ single crystals

    International Nuclear Information System (INIS)

    We have investigated the I-V characteristics of intrinsic Josephson junctions (IJJs) in (Hg, Re)Ba2Ca3Cu4O10+δ [Hg(Re)1234]. Two types of inline junctions with different dimensions were fabricated using a focused Ga+ ion beam from Hg(Re)1234 single crystals grown by the flux method. In the I-V curves of the IJJs, multiple-branches with hysteresis structure similar to those of other HTS IJJs were successfully observed above 80 K. The IJJs with dimension of 1.2 x 0.65 μm2 showed almost step by step switching, while the other with larger size showed uniform-stack switching, which indicated that the switching dynamics in the IJJs were affected by the coupling between junctions. The critical current density, Jc, of both IJJs were high ∼320 kA/cm2 at 4.2 K due to its high Tc and relatively low anisotropy parameter γ=(mc*/mab*)1/2∼25

  13. HERC 1 ubiquitin ligase mutation affects neocortical, CA3 hippocampal and spinal cord projection neurons. An ultrastructural study

    Directory of Open Access Journals (Sweden)

    Rocío eRuiz

    2016-04-01

    Full Text Available The spontaneous mutation tambaleante is caused by the Gly483Glu substitution in the highly conserved N terminal RCC1-like domain of the HERC1 protein, which leads to the increase of mutated protein levels responsible for cerebellar Purkinje cell death by autophagy. Until now, Purkinje cells have been the only central nervous neurons reported as being targeted by the mutation, and their degeneration elicits an ataxic syndrome in adult mutant mice. However, the ultrastructural analysis performed here demonstrates that signs of autophagy, such as autophagosomes, lysosomes, and altered mitochondria, are present in neocortical pyramidal, CA3 hippocampal pyramidal, and spinal cord motor neurons. The main difference is that the reduction in the number of neurons affected in the tambaleante mutation in the neocortex, the hippocampus, and the spinal cord is not so evident as the dramatic loss of cerebellar Purkinje cells. Interestingly, signs of autophagy are absent in both interneurons and neuroglia cells. Affected neurons have in common that they are projection neurons which receive strong and varied synaptic inputs, and possess the highest degree of neuronal activity. Therefore, because the integrity of the ubiquitin-proteasome system is essential for protein degradation and, hence, for normal protein turnover, it could be hypothesized that the deleterious effects of the misrouting of these pathways would depend directly on the neuronal activity.

  14. HERC 1 Ubiquitin Ligase Mutation Affects Neocortical, CA3 Hippocampal and Spinal Cord Projection Neurons: An Ultrastructural Study.

    Science.gov (United States)

    Ruiz, Rocío; Pérez-Villegas, Eva María; Bachiller, Sara; Rosa, José Luis; Armengol, José Angel

    2016-01-01

    The spontaneous mutation tambaleante is caused by the Gly483Glu substitution in the highly conserved N terminal RCC1-like domain of the HERC1 protein, which leads to the increase of mutated protein levels responsible for cerebellar Purkinje cell death by autophagy. Until now, Purkinje cells have been the only central nervous neurons reported as being targeted by the mutation, and their degeneration elicits an ataxic syndrome in adult mutant mice. However, the ultrastructural analysis performed here demonstrates that signs of autophagy, such as autophagosomes, lysosomes, and altered mitochondria, are present in neocortical pyramidal, CA3 hippocampal pyramidal, and spinal cord motor neurons. The main difference is that the reduction in the number of neurons affected in the tambaleante mutation in the neocortex, the hippocampus, and the spinal cord is not so evident as the dramatic loss of cerebellar Purkinje cells. Interestingly, signs of autophagy are absent in both interneurons and neuroglia cells. Affected neurons have in common that they are projection neurons which receive strong and varied synaptic inputs, and possess the highest degree of neuronal activity. Therefore, because the integrity of the ubiquitin-proteasome system is essential for protein degradation and hence, for normal protein turnover, it could be hypothesized that the deleterious effects of the misrouting of these pathways would depend directly on the neuronal activity. PMID:27147983

  15. Dendrites Inhibition in Rechargeable Lithium Metal Batteries

    Science.gov (United States)

    Aryanfar, Asghar

    The specific high energy and power capacities of rechargeable lithium metal (Li0) batteries are ideally suited to portable devices and are valuable as storage units for intermittent renewable energy sources. Lithium, the lightest and most electropositive metal, would be the optimal anode material for rechargeable batteries if it were not for the fact that such devices fail unexpectedly by short-circuiting via the dendrites that grow across electrodes upon recharging. This phenomenon poses a major safety issue because it triggers a series of adverse events that start with overheating, potentially followed by the thermal decomposition and ultimately the ignition of the organic solvents used in such devices. In this thesis, we developed experimental platform for monitoring and quantifying the dendrite populations grown in a Li battery prototype upon charging under various conditions. We explored the effects of pulse charging in the kHz range and temperature on dendrite growth, and also on loss capacity into detached "dead" lithium particles. Simultaneously, we developed a computational framework for understanding the dynamics of dendrite propagation. The coarse-grained Monte Carlo model assisted us in the interpretation of pulsing experiments, whereas MD calculations provided insights into the mechanism of dendrites thermal relaxation. We also developed a computational framework for measuring the dead lithium crystals from the experimental images.

  16. Randomized, double-blind, placebo-controlled, linear dose, crossover study to evaluate the efficacy and safety of a green coffee bean extract in overweight subjects [Retraction

    Directory of Open Access Journals (Sweden)

    Vinson JA

    2014-10-01

    Full Text Available Vinson JA, Burnham BR, Nagendran MV. Diabetes, Metabolic Syndrome and Obesity: Targets and Therapy. 2012;5:21–27. The sponsors of the study cannot assure the validity of the data so we, Joe Vinson and Bryan Burnham, are retracting the paper. This retraction relates to this paper. 

  17. Randomized, double-blind, placebo-controlled, linear dose, crossover study to evaluate the efficacy and safety of a green coffee bean extract in overweight subjects [Retraction

    OpenAIRE

    Vinson JA; Burnham BR; Nagendran MV

    2014-01-01

    Vinson JA, Burnham BR, Nagendran MV. Diabetes, Metabolic Syndrome and Obesity: Targets and Therapy. 2012;5:21–27. The sponsors of the study cannot assure the validity of the data so we, Joe Vinson and Bryan Burnham, are retracting the paper. This retraction relates to this paper. 

  18. Baclofen and adenosine inhibition of synaptic transmission at CA3-CA1 synapses display differential sensitivity to K+ channel blockade.

    Science.gov (United States)

    Skov, Jane; Andreasen, Mogens; Hablitz, John J; Nedergaard, Steen

    2011-05-01

    The metabotropic GABA(B) and adenosine A(1) receptors mediate presynaptic inhibition through regulation of voltage-dependent Ca(2+) channels, whereas K(+) channel regulation is believed to have no role at the CA3-CA1 synapse. We show here that the inhibitory effect of baclofen (20 μM) and adenosine (300 μM) on field EPSPs are differentially sensitive to Cs(+) (3.5 mM) and Ba(2+) (200 μM), but not 4-aminopyridine (100 μM). Barium had no effect on paired-pulse facilitation (PPF) in itself, but gave significant reduction (14 ± 5%) when applied in the presence of baclofen, but not adenosine, suggesting that the effect is presynaptic and selective on the GABA(B) receptor-mediated response. The effect of Ba(2+) on PPF was not mimicked by tertiapin (30 nM), indicating that the underlying mechanism does not involve GIRK channels. Barium did not affect PPF in slices from young rats (P7-P8), suggesting developmental regulation. The above effects of Ba(2+) on adult tissue were reproduced when measuring evoked whole-cell EPSCs from CA1 pyramidal neurons: PPF was reduced by 22 ± 3% in the presence of baclofen and unaltered in adenosine. In contrast, Ba(2+) caused no significant change in frequency or amplitude of miniature EPSCs. The Ba(2+)-induced reduction of PPF was antagonized by LY341495, suggesting metabotropic glutamate receptor involvement. We propose that these novel effects of Ba(2+) and Cs(+) are exerted through blockade of inwardly rectifying K(+) channels in glial cells, which are functionally interacting with the GABA(B) receptor-dependent glutamate release that generates heterosynaptic depression. PMID:21274618

  19. Anomalous behaviour of irreversibility lines in multi-layered superconductor (Cu,C)Ba2Ca3Cu4Oy

    International Nuclear Information System (INIS)

    The physical properties of a multi-layered cuprate superconductor (Cu0.6C0.4)Ba2Ca3Cu4Oy are investigated using high-quality samples of varying oxygen content (y ∼ 11.18-10.34). Samples are synthesized using a newly developed method capable of fine control of the starting oxygen and carbon compositions, followed by annealing under N2 flow at various temperatures to modify the oxygen content. While Tc, the lattice constants and T0 change monotonically with y, the irreversibility lines exhibit a discontinuous drop at y ≤ 10.45 amongst a more gradual decrease. This discontinuity has not been observed before for single- or double-layered CuO2 superconductors. This anomaly is attributed to the presence of two different order parameters in this material, arising from the large difference in carrier concentrations of the outer five-coordinated CuO2 planes and inner four-coordinated CuO2 planes. The superconducting gap in the outer planes develops with decreasing y (approaching the optimal doping state), suppressing the decrease in the irreversibility line, while the carrier insensitivity of the inner planes limits the change in Tc. Two different kinks are also observed in the irreversibility lines, tentatively attributed to the development of the superconducting gap and 2D-3D crossover in a vortex system. Control of the doping state of both the inner and outer planes is demonstrated to be important in the design of Jc and Birr, even if the change in Tc is small. This result is also expected to be applicable to other multi-layered superconductors

  20. (Cu,Tl)Ba2Ca3Cu4Ox compositions: II. Heating rate applied to synthesis of superconducting ceramics

    International Nuclear Information System (INIS)

    Superconducting samples with a starting composition Cu0.5TlxBa2Ca3Cu4O12 (x=1-0.35) were prepared in Au tubes from oxides by using different heating rates. The optimum heating rate was 0.11 deg. C min-1 applied between 860 and 880 deg. C. These samples show the highest content of 1234 phase and the lowest of Ba-Cu-O phases as well as the highest critical temperatures. The highest values were Tc=119.2 K and Tc0=115.1 K. All samples show Jc values around 6x105 A cm-2, at 60 K and 0.5 T. In the rest of the samples, heated by using lower or higher heating rates, a high concentration of 1223 and/or 1245 phases is detected. The content of the 1234 phase and of Ba(Ca,Tl)-Cu-O residual liquid phase, in the samples synthesized for the optimum heating rate, depends on the Tl content in the starting mixture. The influence of the oxygen content in the starting mixture on phase composition is not as strong as of Tl, but it has a major role in establishing the superconducting behaviour of the 1234 grains. Some arguments that suggest the dependence of the transport properties of the non-superconducting matrix on oxygen content will be discussed. In our technological arrangement the determined optimum heating rate can be applied to the synthesis of other single-layered superconducting phases, e.g. 1212 phase from a Cu0.25Tl0.75Ba2CaCu2O8.115 starting composition. (author)

  1. Detecting Danger: The Dendritic Cell Algorithm

    CERN Document Server

    Greensmith, Julie; Cayzer, Steve

    2010-01-01

    The Dendritic Cell Algorithm (DCA) is inspired by the function of the dendritic cells of the human immune system. In nature, dendritic cells are the intrusion detection agents of the human body, policing the tissue and organs for potential invaders in the form of pathogens. In this research, and abstract model of DC behaviour is developed and subsequently used to form an algorithm, the DCA. The abstraction process was facilitated through close collaboration with laboratory- based immunologists, who performed bespoke experiments, the results of which are used as an integral part of this algorithm. The DCA is a population based algorithm, with each agent in the system represented as an 'artificial DC'. Each DC has the ability to combine multiple data streams and can add context to data suspected as anomalous. In this chapter the abstraction process and details of the resultant algorithm are given. The algorithm is applied to numerous intrusion detection problems in computer security including the detection of p...

  2. The Kinetics, Stability and Thermal Contact Resistance of Nickel-Ca3Co4O9 Interfaces Formed by Spark Plasma Sintering

    DEFF Research Database (Denmark)

    Holgate, Tim; Wu, NingYu; Søndergaard, M.;

    2012-01-01

    (Ca3Co4O9) have been formed directly by spark plasma sintering (SPS). An intermediate NiO phase is formed during the SPS processes, which grows during post heating with Co entering from the cobaltate side to form a graded Ni1-xCoxO interfacial layer. The electrical and thermal transport across...

  3. Phosphorylation of the tau protein sequence 199-205 in the hippocampal CA3 region of Syrian hamsters in adulthood and during aging

    NARCIS (Netherlands)

    Hartig, W; Oklejewicz, M; Strijkstra, AM; Boerema, AS; Stieler, J; Arendt, T

    2005-01-01

    Paired helical filaments formed by the abnormally phosphorylated microtubule-associated tau are a main sign of Alzheimer's disease and other neurodegenerative disorders. The hippocampal CA3 region, a brain region with a high degree of synaptic plasticity, is known to be strongly involved in tau hype

  4. Excellent stability of plasma-sprayed bioactive Ca3ZrSi2O9 ceramic coating on Ti-6Al-4V

    International Nuclear Information System (INIS)

    In this work, novel zirconium incorporated Ca-Si based ceramic powder Ca3ZrSi2O9 was synthesized. The aim of this study was to fabricate Ca3ZrSi2O9 coating onto Ti-6Al-4V substrate using atmospheric plasma-spraying technology and to evaluate its potential applications in the fields of orthopedics and dentistry. The phase composition, surface morphologies of the coating were examined by XRD and SEM, which revealed that the Ca3ZrSi2O9 coating was composed of grains around 100 nm and amorphous phases. The bonding strength between the coating and the substrate was 28 ± 4 MPa, which is higher than that of traditional HA coating. The dissolution rate of the coating was assessed by monitoring the ions release and mass loss after immersion in the Tris-HCl buffer solution. The in vitro bioactivity of the coating was determined by observing the formation of apatite on its surface in simulated body fluids. It was found that the Ca3ZrSi2O9 coating possessed both excellent chemical stability and good apatite-formation ability, suggesting its potential use as bone implants.

  5. Irreversibility line and flux pinning properties in a multilayered cuprate superconductor of Ba2Ca3Cu4O8(O,F)2 (Tc = 105 K)

    International Nuclear Information System (INIS)

    Irreversibility line (IL) and flux pinning properties were investigated for a Ba2Ca3Cu4O8(O,F)2 (F-0234) multilayered cuprate superconductor with a Tc of 105 K. The intragrain critical current density (Jc) and irreversibility field (Birr) were determined by using Bean's critical state model for the grain-aligned sample (nominal composition Ba2Ca3Cu4O8.7F1.3). The irreversibility line (IL) of F-0234 is much lower than that of (Cu,C)Ba2Ca3Cu4Oy ((Cu, C)-1234) and HgBa2Ca3Cu4Oy (Hg-1234) in spite of the spacing between the superconducting blocks of F-0234 (7.3 A) being much thinner. The double logarithmic plot of Birr field versus [1-(T/Tc) ] analysis hints that the flux line melting model has been adopted. An anisotropy factor of 65 was calculated from a 3D to 2D crossover field of about 0.95 T. Due to the high anisotropy of this system, a low IL has resulted. The flux pinning force density Fp ( ∼JcB) exhibits scaling behaviour when the magnetic field B is normalized by the Birr field. Analysis of the normalized pinning force reveals that a surface pinning mechanism is dominant and the reduced magnetic field bmax = 0.2 agrees with surface pinning mechanism with closely spaced pins

  6. The Dendritic Hypothesis for Alzheimer’s Disease Pathophysiology

    OpenAIRE

    Cochran, J. Nicholas; Hall, Alicia M.; Roberson, Erik D.

    2013-01-01

    Converging evidence indicates that processes occurring in and around neuronal dendrites are central to the pathogenesis of Alzheimer’s disease. These data support the concept of a “dendritic hypothesis” of AD, closely related to the existing synaptic hypothesis. Here we detail dendritic neuropathology in the disease and examine how Aβ, tau, and AD genetic risk factors affect dendritic structure and function. Finally, we consider potential mechanisms by which these key drivers could affect den...

  7. Silicon dendritic web growth thermal analysis task

    Science.gov (United States)

    Richter, R.; Bhandari, P.

    1985-01-01

    A thermal analysis model is presented which describes the dendritic ribbon process. The model uses a melt-dendrite interface which projects out of the bulk melt as the basic interpretation of the ribbon production process. This is a marked departure from the interpretations of the interface phenomena which were used previously. The model was extensively illustrated with diagrams and pictures of ribbon samples. This model should have great impact on the analyses of experimental data as well as on future design modifications of ribbon-pulling equipment.

  8. Prenatal nicotine and maternal deprivation stress de-regulate the development of CA1, CA3, and dentate gyrus neurons in hippocampus of infant rats.

    Directory of Open Access Journals (Sweden)

    Hong Wang

    Full Text Available Adverse experiences by the developing fetus and in early childhood are associated with profound effects on learning, emotional behavior, and cognition as a whole. In this study we investigated the effects of prenatal nicotine exposure (NIC, postnatal maternal deprivation (MD or the combination of the two (NIC+MD to determine if hippocampal neuron development is modulated by exposure to drugs of abuse and/or stress. Growth of rat offspring exposed to MD alone or NIC+MD was repressed until after weaning. In CA1 but not CA3 of postnatal day 14 (P14 pups, MD increased pyramidal neurons, however, in dentate gyrus (DG, decreased granule neurons. NIC had no effect on neuron number in CA1, CA3 or DG. Unexpectedly, NIC plus MD combined caused a synergistic increase in the number of CA1 or CA3 neurons. Neuron density in CA regions was unaffected by treatment, but in the DG, granule neurons had a looser packing density after NIC, MD or NIC+MD exposure. When septotemporal axes were analyzed, the synergism of stress and drug exposure in CA1 and CA3 was associated with rostral, whereas MD effects were predominantly associated with caudal neurons. TUNEL labeling suggests no active apoptosis at P14, and doublecortin positive neurons and mossy fibers were diminished in NIC+MD relative to controls. The laterality of the effect of nicotine and/or maternal deprivation in right versus left hippocampus was also analyzed and found to be insiginificant. We report for the first time that early life stressors such as postnatal MD and prenatal NIC exposure, when combined, may exhibit synergistic consequences for CA1 and CA3 pyramidal neuron development, and a potential antagonistic influence on developing DG neurons. These results suggest that early stressors may modulate neurogenesis, apoptosis, or maturation of glutamatergic neurons in the hippocampus in a region-specific manner during critical periods of neurodevelopment.

  9. Sustained increase of spontaneous input and spike transfer in the CA3-CA1 pathway following long term potentiation in vivo

    Directory of Open Access Journals (Sweden)

    Oscar eHerreras

    2012-10-01

    Full Text Available Long term potentiation (LTP is commonly used to study synaptic plasticity but the associated changes in the spontaneous activity of individual neurons or the computational properties of neural networks in vivo remain largely unclear. The multisynaptic origin of spontaneous spikes makes difficult estimating the impact of a particular potentiated input. Accordingly, we adopted an approach that isolates pathway-specific postsynaptic activity from raw local field potentials (LFPs in the rat hippocampus in order to study the effects of LTP on ongoing spike transfer between cell pairs in the CA3-CA1 pathway. CA1 Schaffer-specific LFPs elicited by spontaneous clustered firing of CA3 pyramidal cells involved a regular succession of elementary micro-field-EPSPs (gamma-frequency that fired spikes in CA1 units. LTP increased the amplitude but not the frequency of these ongoing excitatory quanta. Also, the proportion of Schaffer-driven spikes in both CA1 pyramidal cells and interneurons increased in a cell-specific manner only in previously connected CA3-CA1 cell pairs, i.e., when the CA3 pyramidal cell had shown pre-LTP significant correlation with firing of a CA1 unit and potentiated spike-triggered average of Schaffer LFPs following LTP. Moreover, LTP produced subtle reorganization of presynaptic CA3 cell assemblies. These findings show effective enhancement of pathway specific ongoing activity which leads to increased spike transfer in potentiated segments of a network. These indicate that plastic phenomena induced by external protocols may intensify spontaneous information flow across specific channels as proposed in transsynaptic propagation of plasticity and synfire chain hypotheses that may be the substrate for different types of memory involving multiple brain structures.

  10. Finite element analysis of maxillary incisor displacement during en-masse retraction according to orthodontic mini-implant position

    Science.gov (United States)

    Song, Jae-Won; Lim, Joong-Ki; Lee, Kee-Joon; Sung, Sang-Jin; Chun, Youn-Sic

    2016-01-01

    Objective Orthodontic mini-implants (OMI) generate various horizontal and vertical force vectors and moments according to their insertion positions. This study aimed to help select ideal biomechanics during maxillary incisor retraction by varying the length in the anterior retraction hook (ARH) and OMI position. Methods Two extraction models were constructed to analyze the three-dimentional finite element: a first premolar extraction model (Model 1, M1) and a residual 1-mm space post-extraction model (Model 2, M2). The OMI position was set at a height of 8 mm from the arch wire between the second maxillary premolar and the first molar (low OMI traction) or at a 12-mm height in the mesial second maxillary premolar (high OMI traction). Retraction force vectors of 200 g from the ARH (-1, +1, +3, and +6 mm) at low or high OMI traction were resolved into X-, Y-, and Z-axis components. Results In M1 (low and high OMI traction) and M2 (low OMI traction), the maxillary incisor tip was extruded, but the apex was intruded, and the occlusal plane was rotated clockwise. Significant intrusion and counter-clockwise rotation in the occlusal plane were observed under high OMI traction and -1 mm ARH in M2. Conclusions This study observed orthodontic tooth movement according to the OMI position and ARH height, and M2 under high OMI traction with short ARH showed retraction with maxillary incisor intrusion. PMID:27478801

  11. Real-time CARS imaging reveals a calpain-dependent pathway for paranodal myelin retraction during high-frequency stimulation.

    Directory of Open Access Journals (Sweden)

    Terry B Huff

    Full Text Available High-frequency electrical stimulation is becoming a promising therapy for neurological disorders, however the response of the central nervous system to stimulation remains poorly understood. The current work investigates the response of myelin to electrical stimulation by laser-scanning coherent anti-Stokes Raman scattering (CARS imaging of myelin in live spinal tissues in real time. Paranodal myelin retraction at the nodes of Ranvier was observed during 200 Hz electrical stimulation. Retraction was seen to begin minutes after the onset of stimulation and continue for up to 10 min after stimulation was ceased, but was found to reverse after a 2 h recovery period. The myelin retraction resulted in exposure of Kv 1.2 potassium channels visualized by immunofluorescence. Accordingly, treating the stimulated tissue with a potassium channel blocker, 4-aminopyridine, led to the appearance of a shoulder peak in the compound action potential curve. Label-free CARS imaging of myelin coupled with multiphoton fluorescence imaging of immuno-labeled proteins at the nodes of Ranvier revealed that high-frequency stimulation induced paranodal myelin retraction via pathologic calcium influx into axons, calpain activation, and cytoskeleton degradation through spectrin break-down.

  12. Elastic Behavior and Platelet Retraction in Low- and High-Density Fibrin Gels

    Science.gov (United States)

    Wufsus, Adam R.; Rana, Kuldeepsinh; Brown, Andrea; Dorgan, John R.; Liberatore, Matthew W.; Neeves, Keith B.

    2015-01-01

    Fibrin is a biopolymer that gives thrombi the mechanical strength to withstand the forces imparted on them by blood flow. Importantly, fibrin is highly extensible, but strain hardens at low deformation rates. The density of fibrin in clots, especially arterial clots, is higher than that in gels made at plasma concentrations of fibrinogen (3–10 mg/mL), where most rheology studies have been conducted. Our objective in this study was to measure and characterize the elastic regimes of low (3–10 mg/mL) and high (30–100 mg/mL) density fibrin gels using shear and extensional rheology. Confocal microscopy of the gels shows that fiber density increases with fibrinogen concentration. At low strains, fibrin gels act as thermal networks independent of fibrinogen concentration. Within the low-strain regime, one can predict the mesh size of fibrin gels by the elastic modulus using semiflexible polymer theory. Significantly, this provides a link between gel mechanics and interstitial fluid flow. At moderate strains, we find that low-density fibrin gels act as nonaffine mechanical networks and transition to affine mechanical networks with increasing strains within the moderate regime, whereas high-density fibrin gels only act as affine mechanical networks. At high strains, the backbone of individual fibrin fibers stretches for all fibrin gels. Platelets can retract low-density gels by >80% of their initial volumes, but retraction is attenuated in high-density fibrin gels and with decreasing platelet density. Taken together, these results show that the nature of fibrin deformation is a strong function of fibrin fiber density, which has ramifications for the growth, embolization, and lysis of thrombi. PMID:25564864

  13. Germ band retraction as a landmark in glucose metabolism during Aedes aegypti embryogenesis

    Directory of Open Access Journals (Sweden)

    Logullo Carlos

    2010-02-01

    Full Text Available Abstract Background The mosquito A. aegypti is vector of dengue and other viruses. New methods of vector control are needed and can be achieved by a better understanding of the life cycle of this insect. Embryogenesis is a part of A. aegypty life cycle that is poorly understood. In insects in general and in mosquitoes in particular energetic metabolism is well studied during oogenesis, when the oocyte exhibits fast growth, accumulating carbohydrates, lipids and proteins that will meet the regulatory and metabolic needs of the developing embryo. On the other hand, events related with energetic metabolism during A. aegypti embryogenesis are unknown. Results Glucose metabolism was investigated throughout Aedes aegypti (Diptera embryonic development. Both cellular blastoderm formation (CBf, 5 h after egg laying - HAE and germ band retraction (GBr, 24 HAE may be considered landmarks regarding glucose 6-phosphate (G6P destination. We observed high levels of glucose 6-phosphate dehydrogenase (G6PDH activity at the very beginning of embryogenesis, which nevertheless decreased up to 5 HAE. This activity is correlated with the need for nucleotide precursors generated by the pentose phosphate pathway (PPP, of which G6PDH is the key enzyme. We suggest the synchronism of egg metabolism with carbohydrate distribution based on the decreasing levels of phosphoenolpyruvate carboxykinase (PEPCK activity and on the elevation observed in protein content up to 24 HAE. Concomitantly, increasing levels of hexokinase (HK and pyruvate kinase (PK activity were observed, and PEPCK reached a peak around 48 HAE. Glycogen synthase kinase (GSK3 activity was also monitored and shown to be inversely correlated with glycogen distribution during embryogenesis. Conclusions The results herein support the hypothesis that glucose metabolic fate changes according to developmental embryonic stages. Germ band retraction is a moment that was characterized as a landmark in glucose

  14. The broad base columellar strut for correction of retracted columella and under rotated tip

    Directory of Open Access Journals (Sweden)

    Amr N. Rabie

    2016-07-01

    Full Text Available Objective: To describe the technique and to detect the efficacy of the broad base columellar strut in correcting retracted columella and under rotated nasal tip. Design: Retrospective chart review. Setting: University-affiliated medical center. Methods: The charts and photographs of patients suffering from columellar retraction with acute columellar-labial angle were reviewed. The columellar-labial angle and the nasal tip projection were measured and calculated from the photos and the columellar show was measured using a fine caliper. Results: The study included 17 patients, 12 females and 5 males with a mean age of 30.2 years ranging from 19 to 49 years, 14 patients had primary surgery while 3 were revision cases, Preoperative columellar-labial angle ranged from 75° to 86° with a mean 82.06 ± 4.08458 SD, while postoperatively it ranged from 92° to 105° with a mean 97.12° ± 3.9825 SD. Columellar show ranged preoperatively from 0.4 to 1.7 mm with a mean 0.94 mm ± 0.38739 SD while postoperatively it ranged from 2.5 to 3.5 mm with a mean of 2.65 mm ± 0.38098 SD. Nasal tip projection preoperatively ranged from 0.45 to 0.58 and postoperatively from 0.51 to 0.59. Conclusions: The broad base columellar strut technique is simple, easy, does not cause excessive tip stiffness and reduces the need to use the plumbing graft in conjunction with the columellar strut, and should help in increasing tip rotation and columellar show reliably and may add to tip projection as required.

  15. Retração rápida de caninos Rapid canine retraction

    Directory of Open Access Journals (Sweden)

    Paulo Renato Carvalho Ribeiro

    2011-02-01

    Full Text Available INTRODUÇÃO: a retração rápida de caninos por distração do ligamento periodontal é uma técnica de movimentação dentária que permite o fechamento de espaço da extração de primeiros pré-molares em um intervalo de duas ou três semanas, proporcionando uma redução significativa no tempo do tratamento ortodôntico. OBJETIVO: apresentar modificações propostas na técnica cirúrgica original e no posicionamento dos distratores. CONCLUSÕES: a retração rápida de caninos é uma técnica que proporciona uma redução significativa no tempo de tratamento ortodôntico. A modificação na técnica cirúrgica proporcionou maior velocidade e segurança ao ato cirúrgico. O distrator posicionado por palatina, no mínimo, proporcionou a preservação da tábua óssea vestibular e evitou a vestibularização dos caninos.INTRODUCTION: Rapid canine retraction through distraction of the periodontal ligament is a tooth movement technique that allows the closure of first premolar extraction space within a period of two to three weeks while providing significant reduction in orthodontic treatment time. OBJECTIVE: To propose changes in the original surgical technique and in the placement of distractors. CONCLUSIONS: Rapid canine retraction is a technique that provides significant reduction in orthodontic treatment time. Changes in the surgical technique provided greater speed and safety in surgery. As a minimum benefit, when positioned palatally, distractors helped to preserve the buccal bone plate and prevented canine proclination.

  16. The bHLH-PAS protein Spineless is necessary for the diversification of dendrite morphology of Drosophila dendritic arborization neurons

    OpenAIRE

    Kim, Michael D.; Jan, Lily Yeh; Jan, Yuh Nung

    2006-01-01

    Dendrites exhibit a wide range of morphological diversity, and their arborization patterns are critical determinants of proper neural connectivity. How different neurons acquire their distinct dendritic branching patterns during development is not well understood. Here we report that Spineless (Ss), the Drosophila homolog of the mammalian aryl hydrocarbon (dioxin) receptor (Ahr), regulates dendrite diversity in the dendritic arborization (da) sensory neurons. In loss-of-function ss mutants, c...

  17. SU-E-T-36: An Investigation of the Margin From CTV to PTV Using Retraction Method for Cervical Carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Wu, D; Chen, J; Hao, Y; Liao, C; Huang, Y; Mo, Y; Wei, Y [The People' s Hospital of Guangxi Zhuang Autonomous Region, Nanning, Guangxi (China)

    2014-06-01

    Purpose: This work employs the retraction method to compute and evaluate the margin from CTV to PTV based on the influence of target dosimetry of setup errors during cervical carcinoma patients treatment. Methods: Sixteen patients with cervical cancer were treated by Elekta synergy and received a total of 305 KV-CBCT images. The iso-center of the initial plans were changed according to the setup errors to simulate radiotherapy and then recalculated the dose distribution using leaf sequences and MUs for individual plans. The margin from CTV to PTV will be concluded both by the method of retracting (Fixed the PTV of the original plan, and retract PTV a certain distance defined as simulative organization CTVnx. The minimum distance value from PTV to CTVnx which get specified doses, namely guarantee at least 99% CTV volume can receive the dose of 95%, is the margin CTV to PTV we found) and the former formula method. Results: (1)The setup errors of 16 patients in X, Y and Z directions were(1.13±2.94) mm,(−1.63±7.13) mm,(−0.65±2.25) mm. (2) The distance between CTVx and PTV was 5, 9 and 3mm in X, Y and Z directions According to 2.5+0.7σ. (3) Transplantation plans displayed 99% of CTVx10- CTVx7 and received 95% of prescription dose, but CTVx6- CTVx3 departed from standard of clinic.In order to protect normal tissues, we selected 7mm as the minimum value of the margin from CTV to PTV. Conclusion: We have test an retraction method for the margin from CTV to PTV evaluation. The retraction method is more reliable than the formula method for calculating the margin from the CTV to the PTV, because it represented practice of treatment, and increasing a new method in this field.

  18. Model of Primary Austenite Dendrite Structure in Hypoeutectic Cast Iron

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The solidification of primary austenite in hypoeutectic gray cast iron was studied by stepped grinding and quantitative metallography. The dendrite structure of primary austenite can be described by three models: typical dendrite crystal model, metamorphic dendrite crystal model and network dendrite crystal model. The dendrite crystals formed according to 3rd model is much more than those formed according to other models in this experiment. The primary austenites are connected each other, and the primary stems of austenite could be regarded as secondary arms and vice versa.

  19. Numerical Simulations of Equiaxed Dendrite Growth Using Phase Field Method

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Phase field method offers the prospect of being able to perform realistic numerical experiments on dendrite growthin a metallic system. In this paper, the equiaxed dendrite evolution during the solidification of a pure material wasnumerically simulated using the phase field model. The equiaxed dendrite growth in a two-dimensional square domainof undercooled melt (nickel) with four-fold anisotropy was simulated. The phase field model equations was solvedusing the explicit finite difference method on a uniform mesh. The formation of various equiaxed dendrite patternswas shown by a series of simulations, and the effect of anisotropy on equiaxed dendrite morphology was investigated.

  20. Dendritic cells in peripheral tolerance and immunity

    DEFF Research Database (Denmark)

    Gad, Monika; Claesson, Mogens Helweg; Pedersen, Anders Elm

    Dendritic cells capable of influencing immunity exist as functionally distinct subsets, T cell-tolerizing and T cell-immunizing subsets. The present paper reviews how these subsets of DCs develop, differentiate and function in vivo and in vitro at the cellular and molecular level. In particular...

  1. Skin Dendritic Cells in Burn Patients

    OpenAIRE

    D’Arpa, N.; D’Amelio, L.; Accardo-Palumbo, A.; Pileri, D.; Mogavero, R.; Amato, G.; Napoli, B.; Alessandro, G.; Lombardo, C.; F. Conte

    2009-01-01

    The body's immunological response to burn injury has been a subject of great inquiry in recent years. Burn injury disturbs the immune system, resulting in a progressive suppression of the immune response that is thought to contribute to the development of sepsis. Dendritic cells (DCs) are potent antigen-presenting cells that possess the ability to stimulate naïve T cells.

  2. Generation of Immune Inhibitory Dendritic Cells and

    Directory of Open Access Journals (Sweden)

    Abediankenari Saeid

    2009-03-01

    Full Text Available Variety of positive as well as negative regulatory signals are provided by antigen presenting cell in particular by dendritic cells. In this research, we studied the capacity of dendritic cells to expand antigen-specific T regulatory cells.We also investigated the role of TGF-beta in induction inhibitory functions of dendritic cells in mixed leukocyte reactions.Dendritic cells were generated from blood CD14+ monocytes with granulocyte-Monocyte colony stimulating factor and interleukin-4 with or without TGF-beta (TGF-β-GM-DC or GM-DC. CD4+ T cell were isolated to assess lymphocyte proliferation by lymphocyte transformation test assay and the ratio of CD4+FOXp3+ CD25+ T cells were determined by fluorescene-activated cell sorter. T cell proliferation responses in GM-DC showed a significance antigen-specific proliferative response comparing with TGFβ-GM -DC. T Cell proliferation was inhibited in co-culture system containing DC-treated TGF-β. It can be suggested that the expsansion of T regulatory by TGF-β-GM-DC provides a means for antigen specific control of unwanted immune reactions.

  3. Antigen dynamics of follicular dendritic cells

    NARCIS (Netherlands)

    Heesters, B.A.

    2015-01-01

    Stromal-derived follicular dendritic cells (FDCs) are a major depot for antigen that are essential for formation of germinal centers, the site where memory and effector B cells differentiate and high-affinity antibody production takes place. Historically, FDCs have been characterized as ‘accessory’

  4. ISOLATION OF CHICKEN FOLLICULAR DENDRITIC CELLS

    Science.gov (United States)

    The aim of the present study was to isolate chicken follicular dendritic cells (FDC). A combination of methods involving panning, iodixanol density gradient centrifugation, and magnetic cell separation technology made it possible to obtain functional FDC from the cecal tonsils from chickens, which h...

  5. DEX-1 and DYF-7 establish sensory dendrite length by anchoring dendritic tips during cell migration.

    Science.gov (United States)

    Heiman, Maxwell G; Shaham, Shai

    2009-04-17

    Cells are devices whose structures delimit function. For example, in the nervous system, neuronal and glial shapes dictate paths of information flow. To understand how cells acquire their shapes, we examined the formation of a sense organ in C. elegans. Using time-lapse imaging, we found that sensory dendrites form by stationary anchoring of dendritic tips during cell-body migration. A genetic screen identified DEX-1 and DYF-7, extracellular proteins required for dendritic tip anchoring, which act cooperatively at the time and place of anchoring. DEX-1 and DYF-7 contain, respectively, zonadhesin and zona pellucida domains, and DYF-7 self-associates into multimers important for anchoring. Thus, unlike other dendrites, amphid dendritic tips are positioned by DEX-1 and DYF-7 without the need for long-range guidance cues. In sequence and function, DEX-1 and DYF-7 resemble tectorins, which anchor stereocilia in the inner ear, suggesting that a sensory dendrite anchor may have evolved into part of a mechanosensor. PMID:19344940

  6. Analyses of retraction declaration in domestic academic journals%国内学术期刊刊登撤稿声明的分析

    Institute of Scientific and Technical Information of China (English)

    丁媛媛

    2011-01-01

    Retraction declaration is an important means of fighting against counterfeit articles used by the academic journals. This article analyzes 45 retraction declarations and 55 retracted articles searched in the domestic databases, and finds out that 64 percent of the retracted articles caused by the academic misconduct; however, most of the retracted articles still could be found completely in the database. The article briefly discusses the features of the retracted research papers, and shows some issues to the academic journal editors when releasing the retraction declarations.%刊登撤稿声明是学术期刊配合学术打假的重要手段。分析从国内数据库中检索到的45篇撤稿声明和被撤的55篇论文,发现因各种学术不端引起的撤稿占64%,大多数被撤论文仍能在数据库中找到全文。初步探讨了被撤论文的特点和发布撤稿声明时应注意的问题。

  7. Superconductivity and thermoelectric power in Tl2Ca2Ba2Cu3O10 and TlCa3BaCu3O9

    International Nuclear Information System (INIS)

    The authors report the synthesis and superconducting temperature of the high-Tc compounds Tl2Ca2Ba2Cu3O10 and TlCa3BaCu3O9. The transition to the superconducting state was measured by the magnetic susceptibility changes and by the temperature dependence of the electrical a.c and d.c. resistivity and by thermoelectric power measurements. For Tl2Ca2Cu3O10 a superconducting transition with zero resistance at 114.5Κ have been observed. Higher Tc with zero resistance at 122Κ have been found in TlCa3BaCu3O9

  8. Synaptic remodeling in the dentate gyrus, CA3, CA1, subiculum, and entorhinal cortex of mice: effects of deprived rearing and voluntary running.

    Science.gov (United States)

    Schaefers, Andrea T U; Grafen, Keren; Teuchert-Noodt, Gertraud; Winter, York

    2010-01-01

    Hippocampal cell proliferation is strongly increased and synaptic turnover decreased after rearing under social and physical deprivation in gerbils (Meriones unguiculatus). We examined if a similar epigenetic effect of rearing environment on adult neuroplastic responses can be found in mice (Mus musculus). We examined synaptic turnover rates in the dentate gyrus, CA3, CA1, subiculum, and entorhinal cortex. No direct effects of deprived rearing on rates of synaptic turnover were found in any of the studied regions. However, adult wheel running had the effect of leveling layer-specific differences in synaptic remodeling in the dentate gyrus, CA3, and CA1, but not in the entorhinal cortex and subiculum of animals of both rearing treatments. Epigenetic effects during juvenile development affected adult neural plasticity in mice, but seemed to be less pronounced than in gerbils. PMID:20508828

  9. Synaptic Remodeling in the Dentate Gyrus, CA3, CA1, Subiculum, and Entorhinal Cortex of Mice: Effects of Deprived Rearing and Voluntary Running

    Directory of Open Access Journals (Sweden)

    Andrea T. U. Schaefers

    2010-01-01

    Full Text Available Hippocampal cell proliferation is strongly increased and synaptic turnover decreased after rearing under social and physical deprivation in gerbils (Meriones unguiculatus. We examined if a similar epigenetic effect of rearing environment on adult neuroplastic responses can be found in mice (Mus musculus. We examined synaptic turnover rates in the dentate gyrus, CA3, CA1, subiculum, and entorhinal cortex. No direct effects of deprived rearing on rates of synaptic turnover were found in any of the studied regions. However, adult wheel running had the effect of leveling layer-specific differences in synaptic remodeling in the dentate gyrus, CA3, and CA1, but not in the entorhinal cortex and subiculum of animals of both rearing treatments. Epigenetic effects during juvenile development affected adult neural plasticity in mice, but seemed to be less pronounced than in gerbils.

  10. Comparison of the effects of Na2CO3, Ca3(PO4)2, and NiO catalysts on the thermochemical liquefaction of microalga Spirulina platensis

    International Nuclear Information System (INIS)

    Highlights: ► We evaluated the effect of catalysts on TCL of microalgae for biofuel production. ► Addition of catalysts affected the product yield and energy consumption ratio in TCL process. ► Addition of Na2CO3 increased the biocrude oil yield, whereas NiO and Ca3(PO4)2 increased the gaseous yields. -- Abstract: This study investigated the effect of three types of catalysts on the yield of biocrude oil from thermochemical liquefaction (TCL) of the microalga, Spirulina platensis. TCL experiments were performed in a 1.8 L batch reactor using an alkali metal catalyst (Na2CO3), an alkaline earth metal (Ca3(PO4)2), and a transition metal oxide (NiO) and compared with non-catalytic TCL results. Na2CO3 was found to increase biocrude oil yield resulting in 51.6% biocrude oil, which was ∼29.2% higher than under non-catalytic conditions and ∼71% and ∼50% higher than when using NiO and Ca3(PO4)2 catalysts, respectively. Presence of NiO and Ca3(PO4)2 increased yields of gaseous products. GC–MS analysis indicated critical differences in chemical composition of the biocrude oil obtained under different catalyst conditions. Biocrude oil from the catalyzed runs had greater abundance of monoaromatic compounds and lesser polyaromatic and aliphatic compounds than that of non-catalyzed reactions. TCL using Na2CO3 reported the lowest energy consumption ratio and recovered highest energy in the form of biocrude oil among all treatments. Algal biocrude oil had an energy density of 34–39 MJ kg−1 compared to 43 MJ kg−1 for petroleum crude, but had higher oxygen and nitrogen levels. In all cases, the solids conversion was more than 94%. Analysis of solids revealed that 40–60% of the initial catalysts were retained in the solid char.

  11. High-energy passively Q-switched laser operation of Yb:Ca3La2(BO3)4 disordered crystal.

    Science.gov (United States)

    Wang, Lisha; Han, Wenjuan; Pan, Zhongben; Xu, Honghao; Chen, Xiaowen; Liu, Junhai; Yu, Haohai; Zhang, Huaijin

    2016-05-01

    Efficient high-energy passively Q-switched laser operation was demonstrated with Yb:Ca3La2(BO3)4 disordered crystal, producing an average output power of 3.0 W at 1018.7 nm, at a pulse repetition frequency of 5.0 kHz; the resulting pulse energy, duration, and peak power were 600 μJ, 5.3 ns, and 113.2 kW, respectively. PMID:27140354

  12. M2 muscarinic acetylcholine receptors regulate long-term potentiation at hippocampal CA3 pyramidal cell synapses in an input-specific fashion

    OpenAIRE

    Zheng, Fang; Wess, Jürgen; Alzheimer, Christian

    2012-01-01

    Muscarinic receptors have long been known as crucial players in hippocampus-dependent learning and memory, but our understanding of the cellular underpinnings and the receptor subtypes involved lags well behind. This holds in particular for the hippocampal CA3 region, where the mechanisms of synaptic plasticity depend on the type of afferent input. Williams and Johnston (Williams S, Johnston D. Science 242: 84–87, 1988; Williams S, Johnston D. J Neurophysiol 64: 1089–1097, 1990) demonstrated ...

  13. Step change in equilibrium magnetization across the second magnetization peak and the peak effect region of a weakly pinned low Tc superconductor, Ca3Rh4Sn13

    International Nuclear Information System (INIS)

    Isothermal magnetization studies in a low Tc type II superconductor, Ca3Rh4Sn13 (Tc≈8.37K), show abrupt step changes in the equilibrium magnetization lines across the second magnetization peak and the peak effect regions suggesting that both of these phenomena are first order phase transitions. We also observed two jumps in the equilibrium magnetization at two different temperature (or field) domains for a constant field (or temperature) in this low Tc superconductor

  14. K+ at an deficient Ca2+ point position in Ca3(VO4)2: on KCa10V7O28

    International Nuclear Information System (INIS)

    Single crystals of KCa10V7O28 have been prepared by crystallization from flux. The yellow-green crystals show rhombohedral symmetry (trigonal space group C63v-R3c, a = 10.830(1), c = 37.860(1) A, Z = 6). The differences of the crystal chemistry are discussed with respect to the isotypic compound Ca3(VO4)2. K+ replaces exclusively Ca2+ ions at one deficient point position. (orig.)

  15. Processing and in vitro bioactivity of a β-Ca3(PO4)2-CaMg(SiO3)2 ceramic with the eutectic composition

    International Nuclear Information System (INIS)

    In this study, a dense bioactive ceramic, with nominal composition (wt.%) 40 Ca3(PO4)2-60 CaMg(SiO3)2, was prepared by solid state sintering of homogeneous compacted mixtures of fine synthetic Ca3(PO4)2 and CaMg(SiO3)2 powders. The results obtained by X-ray diffraction and field emission scanning electron microscopy with microanalysis indicate that the ceramic composite showed a fine grained and homogeneous microstructure consisting of diopside (CaMg(SiO3)2) and whitlockite (β-Ca3(PO4)2ss) grains with very small amounts of apatite. The flexural strength and elastic modulus values of the composite are similar to those of cortical human bone. Bioactivity was experimentally evaluated by examining in vitro apatite formation in simulated body fluid (SBF). In addition, a simulation of the dissolution properties of the different phases present in the material in SBF was carried out by thermodynamic calculations, with the purpose of understanding the in vitro results obtained. The experimental results demonstrated that, during soaking in SBF, the grains of whitlockite dissolved preferentially than those of diopside, leaving a porous surface layer rich in diopside. Subsequently, partial dissolution of the remaining diopside occurred and the porous surface of the ceramic became coated by a bone-like apatite layer after 7 days in SBF. This bio ceramic containing β-Ca3(PO4)2 and CaMg(SiO3)2 is expected to be useful to fabricate scaffolds for bone repair. (Author)

  16. Disinhibition of hippocampal CA3 neurons induced by suppression of an adenosine A1 receptor-mediated inhibitory tonus: Pre- and postsynaptic components

    OpenAIRE

    Alzheimer, Christian; Sutor, Bernd; Ten Bruggencate, Gerrit

    1993-01-01

    Intracellular recordings were performed on hippocampal CA3 neuronsin vitro to investigate the inhibitory tonus generated by endogenously produced adenosine in this brain region. Bath application of the highly selective adenosine A1 receptor antagonist 1,3-dipropyl-8-cyclopentylxanthine at concentrations up to 100 nM induced both spontaneous and stimulus-evoked epileptiform burst discharges. Once induced, the 1,3-dipropyl-8-cyclopentylxanthine-evoked epileptiform activity was apparently irreve...

  17. Hypersensitivity of the hippocampal CA3 region to stress-induced neurodegeneration and amyloidogenesis in a rat model of surgical menopause

    OpenAIRE

    Zhang, Quan-guang; Wang, Rui-Min; Scott, Erin; Han, Dong; Dong, Yan; Tu, Jing-yi; Yang, Fang; Reddy Sareddy, Gangadhara; Ratna K. Vadlamudi; Brann, Darrell W.

    2013-01-01

    Females who enter menopause prematurely via bilateral ovariectomy (surgical menopause) have a significantly increased risk for cognitive decline and dementia. To help elucidate the mechanisms underlying this phenomenon, we used an animal model of surgical menopause, long-term (10-week) bilateral ovariectomy in female rats. Herein, we demonstrate that long-term oestrogen deprivation dramatically increases sensitivity of the normally resistant hippocampal CA3 region to ischaemic stress, an effe...

  18. Asymmetry in signal propagation between the soma and dendrites plays a key role in determining dendritic excitability in motoneurons.

    Directory of Open Access Journals (Sweden)

    Hojeong Kim

    Full Text Available It is widely recognized that propagation of electrophysiological signals between the soma and dendrites of neurons differs depending on direction, i.e. it is asymmetric. How this asymmetry influences the activation of voltage-gated dendritic channels, and consequent neuronal behavior, remains unclear. Based on the analysis of asymmetry in several types of motoneurons, we extended our previous methodology for reducing a fully reconstructed motoneuron model to a two-compartment representation that preserved asymmetric signal propagation. The reduced models accurately replicated the dendritic excitability and the dynamics of the anatomical model involving a persistent inward current (PIC dispersed over the dendrites. The relationship between asymmetric signal propagation and dendritic excitability was investigated using the reduced models while varying the asymmetry in signal propagation between the soma and the dendrite with PIC density constant. We found that increases in signal attenuation from soma to dendrites increased the activation threshold of a PIC (hypo-excitability, whereas increases in signal attenuation from dendrites to soma decreased the activation threshold of a PIC (hyper-excitability. These effects were so strong that reversing the asymmetry in the soma-to-dendrite vs. dendrite-to-soma attenuation, reversed the correlation between PIC threshold and distance of this current source from the soma. We propose the tight relation of the asymmetric signal propagation to the input resistance in the dendrites as a mechanism underlying the influence of the asymmetric signal propagation on the dendritic excitability. All these results emphasize the importance of maintaining the physiological asymmetry in dendritic signaling not only for normal function of the cells but also for biophysically realistic simulations of dendritic excitability.

  19. Electroconvulsive stimulations prevent stress-induced morphological changes in the hippocampus

    DEFF Research Database (Denmark)

    Hageman, I; Nielsen, M; Wörtwein, Gitta;

    2008-01-01

    Stress can precipitate major depression and other disorders linked to hippocampal shrinkage. It is hypothesized but not established that treatment of these disorders reverses and prevents the hippocampal changes. Dendritic retraction of individual neurons might in concert with other pathophysiolo......Stress can precipitate major depression and other disorders linked to hippocampal shrinkage. It is hypothesized but not established that treatment of these disorders reverses and prevents the hippocampal changes. Dendritic retraction of individual neurons might in concert with other...... pathophysiological events contribute to the shrinkage phenomenon. Animal studies have shown that various stress paradigms can induce dendritic retraction in the CA3 pyramidal neurons of the hippocampus. Since electroconvulsive treatment is the most effective treatment in humans with major depression, we investigated...

  20. Effects of conducting oxide barrier layers on the stability of Crofer® 22 APU/Ca3Co4O9 interfaces

    DEFF Research Database (Denmark)

    Holgate, Tim C.; Han, Li; Wu, NingYu;

    2014-01-01

    available high-chrome iron alloy (i.e., Crofer® 22 APU) serving as the interconnect metal was spray coated with LaNi0.6Fe0.4O3 (LNFO) or (Mn,Co)3O4 spinel and then interfaced with a p-type thermoelectric material—calcium cobaltate (Ca3Co4O9)—using spark plasma sintering. The interfaces have been...... characterized in terms of their thermal and electronic transport properties and chemical stability. With long-term exposure of the interfaced samples to 800 °C in air, the cobalt–manganese spinel acted as a diffusion barrier between the Ca3Co4O9 and the Crofer® 22 APU alloy resulting in improved interfacial...... stability compared to that of samples containing LNFO as a barrier layer, and especially those without any barrier. The initial area specific interfacial resistance of the Ca3Co4O9/(Mn,Co)3O4/Crofer® 22 APU interface at 800 °C was found to be ∼1 mΩ·cm2....

  1. Revising the Subsystem Nurse’s A-Phase-Silicocarnotite within the System Ca3(PO42–Ca2SiO4

    Directory of Open Access Journals (Sweden)

    Patricia Ros-Tárraga

    2016-04-01

    Full Text Available The subsystem Nurse’s A-phase-silicocarnotite within the system Ca3(PO42–Ca2SiO4 was conducted as a preliminary step toward obtaining new biomaterials with controlled microstructures. Phase composition of the resulting ceramics was studied by X-ray diffraction, differential thermal analysis, and scanning electron microscopy with attached wavelength dispersive spectroscopy. The results showed that the sub-system presents an invariant eutectoid point at 1366 ± 4 °C with a composition of 59.5 wt % Ca3(PO42 and 40.5 wt % Ca2SiO4, and typical eutectoid microstructure of lamellae morphology. These results are in disagreement with the previous reported data, which locate the invariant eutectoid point at 1250 ± 20 °C with a composition of 55 wt % Ca3(PO42 and 45 wt % Ca2SiO4. In addition, cell attachment testing showed that the new eutectoid material supported the mesenchymal stem cell adhesion and spreading, and the cells established close contact with the ceramic after 28 days of culture. These findings indicate that the new ceramic material with eutectoid microstructure of lamellae morphology possesses good bioactivity and biocompatibility and might be a promising bone implant material.

  2. Synthesis and luminescence properties of a broad-band red phosphor Ca3Si2O7:Eu2+ for warm white light-emitting diodes

    International Nuclear Information System (INIS)

    Single-phase broad-band red-emitting Ca3Si2O7:Eu2+ phosphors, with photoluminescence features that qualify them as candidates for white light-emitting diodes applications, were successfully synthesized via a modified solid-state reaction method that employed H3BO3 as a flux. The phosphors produced have an intense broad red emission band, with a peak at 603 nm, a full width at half maximum of 110 nm, and color coordinates of (0.550, 0.438). Concentration quenching occurred at 0.01 mol Eu2+. The discussion of the results shows that Eu2+ ions should be accommodated at the Ca-sites of the lattice, dipole-dipole interactions should predominantly govern the energy transfer mechanism among them, and the critical distance between them is ∼31 A. - Highlights: → Pure Ca3Si2O7:Eu2+ phosphor was successfully synthesized by adding H3BO3 . → Effects of H3BO3 on phase formation and emission intensity were presented. → Luminescence properties in conjunction with Ca3Si2O7 structure were studied. → Energy transfer mechanism of Eu2+ and its critical distance were proposed.

  3. The GLP-1 Receptor Agonist Exendin-4 and Diazepam Differentially Regulate GABAA Receptor-Mediated Tonic Currents in Rat Hippocampal CA3 Pyramidal Neurons.

    Directory of Open Access Journals (Sweden)

    Sergiy V Korol

    Full Text Available Glucagon-like peptide-1 (GLP-1 is a metabolic hormone that is secreted in a glucose-dependent manner and enhances insulin secretion. GLP-1 receptors are also found in the brain where their signalling affects neuronal activity. We have previously shown that the GLP-1 receptor agonists, GLP-1 and exendin-4 enhanced GABA-activated synaptic and tonic currents in rat hippocampal CA3 pyramidal neurons. The hippocampus is the centre for memory and learning and is important for cognition. Here we examined if exendin-4 similarly enhanced the GABA-activated currents in the presence of the benzodiazepine diazepam. In whole-cell recordings in rat brain slices, diazepam (1 μM, an allosteric positive modulator of GABAA receptors, alone enhanced the spontaneous inhibitory postsynaptic current (sIPSC amplitude and frequency by a factor of 1.3 and 1.6, respectively, and doubled the tonic GABAA current normally recorded in the CA3 pyramidal cells. Importantly, in the presence of exendin-4 (10 nM plus diazepam (1 μM, only the tonic but not the sIPSC currents transiently increased as compared to currents recorded in the presence of diazepam alone. The results suggest that exendin-4 potentiates a subpopulation of extrasynaptic GABAA receptors in the CA3 pyramidal neurons.

  4. Photoluminescence investigation of rare-earth activated GdCa3(GaO)3(BO3)4 phosphors under UV excitation

    International Nuclear Information System (INIS)

    A borate compound was adopted as a new host material of Eu3+ and Tb3+ activators to fabricate efficient luminescence materials. The phosphor compositions, Gd1-xEuxCa3(GaO)3(BO3)4 and Gd1-xTbxCa3(GaO)3(BO3)4, were synthesized by conventional solid-state reactions. The crystalline phases of the resulting powders were identified using an X-ray diffraction system. Their photoluminescence properties were investigated under long-wavelength UV excitation. The Eu3+-doped and Tb3+-doped GdCa3(GaO)3(BO3)4 phosphors efficiently emitted red and green light, respectively. The temperature dependency of emission intensity was measured in a range from room temperature to 150 deg. C. The emission intensities of the red and green phosphors at 150 deg. C are 87% and 91% of those at room temperature, respectively. In addition, the decay times of both the red and green phosphors are shorter than 3 ms

  5. The functional nature of synaptic circuitry is altered in area CA3 of the hippocampus in a mouse model of Down's syndrome

    Science.gov (United States)

    Hanson, Jesse E; Blank, Martina; Valenzuela, Ricardo A; Garner, Craig C; Madison, Daniel V

    2007-01-01

    Down's syndrome (DS) is the most common cause of mental retardation, and memory impairments are more severe in DS than in most if not all other causes of mental retardation. The Ts65Dn mouse, a genetic model of DS, exhibits phenotypes of DS, including memory impairments indicative of hippocampal dysfunction. We examined functional synaptic connectivity in area CA3 of the hippocampus of Ts65Dn mice using organotypic slice cultures as a model. We found reductions in multiple measures of synaptic function in both excitatory and inhibitory inputs to pyramidal neurons in CA3 of the Ts65Dn hippocampus. However, associational synaptic connections between pyramidal neurons were more abundant and more likely to be active rather than silent in the Ts65Dn hippocampus. Synaptic potentiation was normal in these associational connections. Decreased overall functional synaptic input onto pyramidal neurons expressed along with the specific hyperconnectivity of associational connections between pyramidal neurons will result in predictable alterations of CA3 network function, which may contribute to the memory impairments seen in DS. PMID:17158177

  6. Sleeping dendrites: fiber-optic measurements of dendritic calcium activity in freely moving and sleeping animals

    Directory of Open Access Journals (Sweden)

    Julie Seibt

    2014-03-01

    Full Text Available Dendrites are the post-synaptic sites of most excitatory and inhibitory synapses in the brain, making them the main location of cortical information processing and synaptic plasticity. Although current hypotheses suggest a central role for sleep in proper cognitive function and brain plasticity, virtually nothing is known about changes in dendritic activity across the sleep-wake cycle and how waking experience modifies this activity. To start addressing these questions, we developed a method that allows long-term recordings of EEGs/EMG combined with in vivo cortical calcium (Ca2+ activity in freely moving and sleeping rats. We measured Ca2+ activity from populations of dendrites of layer (L 5 pyramidal neurons (n = 13 rats that we compared with Ca2+ activity from populations of neurons in L2/3 (n = 11 rats. L5 and L2/3 neurons were labelled using bolus injection of OGB1-AM or GCaMP6 (1. Ca2+ signals were detected using a fiber-optic system (cannula diameter = 400µm, transmitting the changes in fluorescence to a photodiode. Ca2+ fluctuations could then be correlated with ongoing changes in brain oscillatory activity during 5 major brain states: active wake [AW], quiet wake [QW], NREM, REM and NREM-REM transition (or intermediate state, [IS]. Our Ca2+ recordings show large transients in L5 dendrites and L2/3 neurons that oscillate predominantly at frequencies In summary, we show that this technique is successful in monitoring fluctuations in ongoing dendritic Ca2+ activity during natural brain states and allows, in principle, to combine behavioral measurement with imaging from various brain regions (e.g. deep structures in freely behaving animals. Using this method, we show that Ca2+ transients from populations of L2/3 neurons and L5 dendrites are deferentially regulated across the sleep/wake cycle, with dendritic activity being the highest during the IS sleep. Our correlation analysis suggests that specific sleep EEG activity during NREM and IS

  7. State Administrative Legal Review on the Bill of Retraction Law of Corrupted Assets in Eradication Effort of Corruption in Indonesia

    Directory of Open Access Journals (Sweden)

    Dian Puji Simatupang

    2011-09-01

    Full Text Available Since eradicating corruption having been continously encouraged by late governments – and until now – , there would not be less important as to retracting the corrupted assets. There are many aspects to be considered in doing such action, such as manifesting the legal aspects of administrative law, and so other applied national regulations. By these regulations, such as Law No. 7 of 2006 on Ratification of United Nations Convention against Corruption, 2003 (Konvensi Perserikatan Bangsa Bangsa Anti-Korupsi, 2003, Law Number 25 of 2003 On Amendment to Law Number 15 of 2002 on Money Laundering, Act 30 of 2002 on Corruption Eradication Commission, Law Number 20 Year 2001 regarding Amendment to Law Number 31 Year 1999 on the Eradication of Corruption, and Government Regulation Number 65 of 1999 on Implementation Procedures for Examination of State Property, retraction the corrupted assets should be define in order to get known about eradicating corruption.

  8. A Genome-Wide Screen for Dendritically Localized RNAs Identifies Genes Required for Dendrite Morphogenesis.

    Science.gov (United States)

    Misra, Mala; Edmund, Hendia; Ennis, Darragh; Schlueter, Marissa A; Marot, Jessica E; Tambasco, Janet; Barlow, Ida; Sigurbjornsdottir, Sara; Mathew, Renjith; Vallés, Ana Maria; Wojciech, Waldemar; Roth, Siegfried; Davis, Ilan; Leptin, Maria; Gavis, Elizabeth R

    2016-01-01

    Localizing messenger RNAs at specific subcellular sites is a conserved mechanism for targeting the synthesis of cytoplasmic proteins to distinct subcellular domains, thereby generating the asymmetric protein distributions necessary for cellular and developmental polarity. However, the full range of transcripts that are asymmetrically distributed in specialized cell types, and the significance of their localization, especially in the nervous system, are not known. We used the EP-MS2 method, which combines EP transposon insertion with the MS2/MCP in vivo fluorescent labeling system, to screen for novel localized transcripts in polarized cells, focusing on the highly branched Drosophila class IV dendritic arborization neurons. Of a total of 541 lines screened, we identified 55 EP-MS2 insertions producing transcripts that were enriched in neuronal processes, particularly in dendrites. The 47 genes identified by these insertions encode molecularly diverse proteins, and are enriched for genes that function in neuronal development and physiology. RNAi-mediated knockdown confirmed roles for many of the candidate genes in dendrite morphogenesis. We propose that the transport of mRNAs encoded by these genes into the dendrites allows their expression to be regulated on a local scale during the dynamic developmental processes of dendrite outgrowth, branching, and/or remodeling. PMID:27260999

  9. Evaluating Local Primary Dendrite Arm Spacing Characterization Techniques Using Synthetic Directionally Solidified Dendritic Microstructures

    Science.gov (United States)

    Tschopp, Mark A.; Miller, Jonathan D.; Oppedal, Andrew L.; Solanki, Kiran N.

    2015-10-01

    Microstructure characterization continues to play an important bridge to understanding why particular processing routes or parameters affect the properties of materials. This statement certainly holds true in the case of directionally solidified dendritic microstructures, where characterizing the primary dendrite arm spacing is vital to developing the process-structure-property relationships that can lead to the design and optimization of processing routes for defined properties. In this work, four series of simulations were used to examine the capability of a few Voronoi-based techniques to capture local microstructure statistics (primary dendrite arm spacing and coordination number) in controlled (synthetically generated) microstructures. These simulations used both cubic and hexagonal microstructures with varying degrees of disorder (noise) to study the effects of length scale, base microstructure, microstructure variability, and technique parameters on the local PDAS distribution, local coordination number distribution, bulk PDAS, and bulk coordination number. The Voronoi tesselation technique with a polygon-side-length criterion correctly characterized the known synthetic microstructures. By systematically studying the different techniques for quantifying local primary dendrite arm spacings, we have evaluated their capability to capture this important microstructure feature in different dendritic microstructures, which can be an important step for experimentally correlating with both processing and properties in single crystal nickel-based superalloys.

  10. A Genome-Wide Screen for Dendritically Localized RNAs Identifies Genes Required for Dendrite Morphogenesis

    Science.gov (United States)

    Misra, Mala; Edmund, Hendia; Ennis, Darragh; Schlueter, Marissa A.; Marot, Jessica E.; Tambasco, Janet; Barlow, Ida; Sigurbjornsdottir, Sara; Mathew, Renjith; Vallés, Ana Maria; Wojciech, Waldemar; Roth, Siegfried; Davis, Ilan; Leptin, Maria; Gavis, Elizabeth R.

    2016-01-01

    Localizing messenger RNAs at specific subcellular sites is a conserved mechanism for targeting the synthesis of cytoplasmic proteins to distinct subcellular domains, thereby generating the asymmetric protein distributions necessary for cellular and developmental polarity. However, the full range of transcripts that are asymmetrically distributed in specialized cell types, and the significance of their localization, especially in the nervous system, are not known. We used the EP-MS2 method, which combines EP transposon insertion with the MS2/MCP in vivo fluorescent labeling system, to screen for novel localized transcripts in polarized cells, focusing on the highly branched Drosophila class IV dendritic arborization neurons. Of a total of 541 lines screened, we identified 55 EP-MS2 insertions producing transcripts that were enriched in neuronal processes, particularly in dendrites. The 47 genes identified by these insertions encode molecularly diverse proteins, and are enriched for genes that function in neuronal development and physiology. RNAi-mediated knockdown confirmed roles for many of the candidate genes in dendrite morphogenesis. We propose that the transport of mRNAs encoded by these genes into the dendrites allows their expression to be regulated on a local scale during the dynamic developmental processes of dendrite outgrowth, branching, and/or remodeling. PMID:27260999

  11. A Genome-Wide Screen for Dendritically Localized RNAs Identifies Genes Required for Dendrite Morphogenesis

    Directory of Open Access Journals (Sweden)

    Mala Misra

    2016-08-01

    Full Text Available Localizing messenger RNAs at specific subcellular sites is a conserved mechanism for targeting the synthesis of cytoplasmic proteins to distinct subcellular domains, thereby generating the asymmetric protein distributions necessary for cellular and developmental polarity. However, the full range of transcripts that are asymmetrically distributed in specialized cell types, and the significance of their localization, especially in the nervous system, are not known. We used the EP-MS2 method, which combines EP transposon insertion with the MS2/MCP in vivo fluorescent labeling system, to screen for novel localized transcripts in polarized cells, focusing on the highly branched Drosophila class IV dendritic arborization neurons. Of a total of 541 lines screened, we identified 55 EP-MS2 insertions producing transcripts that were enriched in neuronal processes, particularly in dendrites. The 47 genes identified by these insertions encode molecularly diverse proteins, and are enriched for genes that function in neuronal development and physiology. RNAi-mediated knockdown confirmed roles for many of the candidate genes in dendrite morphogenesis. We propose that the transport of mRNAs encoded by these genes into the dendrites allows their expression to be regulated on a local scale during the dynamic developmental processes of dendrite outgrowth, branching, and/or remodeling.

  12. TREATMENT OF PRIMARY PALPEBRAL RETRACTION WITH ACUPOINT—INJECTION AND CHINESE MEDICINAL HERBS

    Institute of Scientific and Technical Information of China (English)

    朱新民; LiPeifang

    2000-01-01

    In the present paper,the therapeutic effect of combined therapy of acupoint-injection and Chinese medicinal herbs was observed in 59cases of primary palpebral retraction patients.These 59patients were divided into treatment group(n=38,treated with acupoint-injection and Chinese medicinal herbs)and control group(n=21,treated with Chinese medicinal herbs alone).After3 courses of treatment.of the 38cases in treatment group,25(65.8%)were cured,8(21.1%)had marked improement and5(13.2%)had improement;of the 21cases in control group,8(38.1%)were cured,9(42.9%)had marked improement,2(9.5%)had improement6 and2(9.5%)were ineffective.Statistical analysis showed a si9gnificant difference between the two groups in the therapeu-tic effect.The cure rate of experimental group was apparently higher than athat of the control group,i.e.the therapeutic effect of the combined therapy of acupoint-injection and Chinese medicinal herbs was superior to that of Chinese medicinal herbs alone.

  13. Diagnosis and management of miliary tuberculosis: current state and future perspectives [Retraction

    Directory of Open Access Journals (Sweden)

    Ray S

    2015-09-01

    Full Text Available Ray S, Talukdar A, Kundu S, Khanra D, Sonthalia N. Ther Clin Risk Mngmt. 2013;9:9–26.The editor of the Indian Journal of Medical Research has brought to our attention the unacknowledged re-use of significant portions of text in the above article. The source of much of the text appears to be from:Sharma SK, Mohan A, Sharma A. Challenges in the diagnosis and treatment of miliary tuberculosis. Indian J Med Res. 135, May 2012, pp 703–730.Dr Ray comments thus: “Regarding the similarities found we want to clarify that this apparent plagiarism is not an intentional act and likely to be factual error. In any way, we do not want to undermine scientific pursuit or vitiate the investigational spirit of hard work and creativity. Please be informed that the different portions of the review were written by different co-authors and most of them were postgraduate students at that time. It seems that they have taken materials/ideas from previously published source unaware of the issues of plagiarism.” This retraction relates to this paper

  14. RETRACTED: An overview of mathematical modeling of electrochemical supercapacitors/ultracapacitors

    Science.gov (United States)

    Ike, Innocent S.; Sigalas, Iakovos; Iyuke, Sunny; Ozoemena, Kenneth I.

    2015-01-01

    This article has been retracted at the request of the Editor-in-Chief, with agreement of the authors: please see Elsevier Policy on Article Withdrawal. Substantial parts of this review paper are similar to the texts of existing papers in the literature. The co-authors state that the corresponding author submitted the manuscript without their approval. The following works are affected: IEEE Transactions on Power Electronics, 26 (2011) 3472-3480, http://dx.doi.org/10.1109/TPEL.2011.2161096 The Journal of Physical Chemistry Letters, 4 (2013) 1260-1267, http://dx.doi.org/10.1021/jz4002967 The Journal of Physical Chemistry Letters, 4 (2013), 3367-3376, http://dx.doi.org/10.1021/jz4014163 Physical Chemistry Chemical Physics, 16 (2014), 6519-6538, http://dx.doi.org/10.1039/c3cp55186e The Authors unreservedly apologise for this violation of the publishing policies, and offer sincere apologies to the parties affected. The journal apologises to its readers and the authors that the overlap was not detected during the submission and review process.

  15. Retraction of colonies and structures of Aspergillus Spp. as a possible high dose sensor

    International Nuclear Information System (INIS)

    Changes in the length of macro-and microscopic structures of irradiated Aspergillus spp. colonies were investigated in this work in search for correlations with radiation dose. Effects related to growth and morphology produced by exposure to radiation doses ranging from 0.0 up to 8.0 kGy on strains of A. flavus (CMT 00079), A. parasiticus (CMT 00064) and A ochraceus (CMT 00145) were analyzed. Fungal colonies were inoculated on fresh peanut seeds and incubated for 5 days at 25°C. On the sixth day the samples were irradiated and moved to Petri dishes containing PDA culture medium where they remained incubated for 7 days at 25°C Post irradiation growth was periodically monitored by visual inspections and measurements of mycelial diameters. In addition, microscopic analyses were performed to determine the length of the major structures of the colonies. It has been found that irradiation causes a decrease in the diameter of colonies as well as in the length of microscopic structures of the fungus. The amount of retraction has been found to be strongly correlated to radiation dose. Such findings hint at the possibility of using in situ Aspergillus spp. colonies as high-dose living dosimeters in the event of massive radiation exposures. (author)

  16. Retraction of colonies and structures of Aspergillus Spp. as a possible high dose sensor

    Energy Technology Data Exchange (ETDEWEB)

    Borges, Valeria B., E-mail: valeriabborges@hotmail.com [Coordenacao dos Programas de Pos-Graduacao em Processos Quimicos e Bioquimicos (EQ/UFRJ), Rio de Janeiro, RJ (Brazil). Escola de Quimica; Vital, Helio C., E-mail: vital@ctex.eb.br [Centro Tecnologico do Exercito (DDQBN/CTEx), Rio de Janeiro, RJ (Brazil). Div. de Defesa Quimica, Biologica e Nuclear. Secao de Defesa Nuclear; Moraes, Aurea M.L., E-mail: ltbbf@ioc.fiocruz.br [Instituto Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, RJ (Brazil). Departamento de Micologia

    2013-07-01

    Changes in the length of macro-and microscopic structures of irradiated Aspergillus spp. colonies were investigated in this work in search for correlations with radiation dose. Effects related to growth and morphology produced by exposure to radiation doses ranging from 0.0 up to 8.0 kGy on strains of A. flavus (CMT 00079), A. parasiticus (CMT 00064) and A ochraceus (CMT 00145) were analyzed. Fungal colonies were inoculated on fresh peanut seeds and incubated for 5 days at 25°C. On the sixth day the samples were irradiated and moved to Petri dishes containing PDA culture medium where they remained incubated for 7 days at 25°C Post irradiation growth was periodically monitored by visual inspections and measurements of mycelial diameters. In addition, microscopic analyses were performed to determine the length of the major structures of the colonies. It has been found that irradiation causes a decrease in the diameter of colonies as well as in the length of microscopic structures of the fungus. The amount of retraction has been found to be strongly correlated to radiation dose. Such findings hint at the possibility of using in situ Aspergillus spp. colonies as high-dose living dosimeters in the event of massive radiation exposures. (author)

  17. Ergodic Retraction Theorem and Weak Convergence Theorem for Reversible Semigroups of Non-Lipschitzian Mappings

    Institute of Scientific and Technical Information of China (English)

    Liu Chuan ZENG

    2006-01-01

    Let G be a semitopological semigroup. Let C be a closed convex subset of a uniformly convex Banach space E with a Frechet differentiable norm, and T = {Tt : t ∈ G} be a continuous representation of G as nearly asymptotically nonexpansive type mappings of C into itself such that the common fixed point set F(T) of T in C is nonempty. It is shown that if G is right reversible, then for each almost-orbit u(.) of T, ∩s∈G co{u(t): t ≥ s} ∩ F(T) consists of at most one point. Furthermore,∩s∈G co{Ttx: t ≥ s}∩ F(T) is nonempty for each x ∈ C if and only if there exists a nonlinear ergodic retraction P of C onto F(T) such that PTs = TsP = P for all s ∈ G and Px ∈ co{Tsx: s ∈ G} for each x ∈ C. This result is applied to study the problem of weak convergence of the net {u(t): t ∈ G}to a common fixed point of T.

  18. Dendritic nanocomposite for delivery of antibacterial agent

    Institute of Scientific and Technical Information of China (English)

    Pureti Madhu Kumar; PSrinivasa Babu; Shaik Rasheed; Ramadoss Karthikeyan

    2013-01-01

    Objective: To develop and explore the use of PEGylated poly (propylene imine) dendritic architecture for the delivery of an anti bacterial bioactive, Trimethoprim. Methods: For this study, PEGylated poly(propylene imine) dendritic architecture was synthesized and loaded with Trimethoprim and targeted to the resistant producing strains of both gram positive and gram negative. The antibacterial activity was carried out by agar well-diffusion method to compare zone of inhibition with standard drug and plain PPI dendrimer. Results: The study showed that the Trimethoprim loaded dendrimer has significant antibacterial activity than the plain PPI dendrimer, but standard drug was not shown zone of inhibition upon both microorganisms butKlebsiella pneumoniae (K. pneumoniae) the pure drug showed activity. Conclusions: In this study antibacterial activity of synthesized system is also relatively safer and holds potential to deliver any other antibacterial agent to the resistant producing strains.

  19. Dendritic Cells for SYN Scan Detection

    CERN Document Server

    Greensmith, Julie

    2010-01-01

    Artificial immune systems have previously been applied to the problem of intrusion detection. The aim of this research is to develop an intrusion detection system based on the function of Dendritic Cells (DCs). DCs are antigen presenting cells and key to activation of the human immune system, behaviour which has been abstracted to form the Dendritic Cell Algorithm (DCA). In algorithmic terms, individual DCs perform multi-sensor data fusion, asynchronously correlating the the fused data signals with a secondary data stream. Aggregate output of a population of cells, is analysed and forms the basis of an anomaly detection system. In this paper the DCA is applied to the detection of outgoing port scans using TCP SYN packets. Results show that detection can be achieved with the DCA, yet some false positives can be encountered when simultaneously scanning and using other network services. Suggestions are made for using adaptive signals to alleviate this uncovered problem.

  20. Lysophosphatidylinositol causes neurite retraction via GPR55, G13 and RhoA in PC12 cells.

    Directory of Open Access Journals (Sweden)

    Yutaro Obara

    Full Text Available GPR55 was recently identified as a putative receptor for certain cannabinoids, and lysophosphatidylinositol (LPI. Recently, the role of cannabinoids as GPR55 agonists has been disputed by a number of reports, in part, because studies investigating GPR55 often utilized overexpression systems, such as the GPR55-overexpressing HEK293 cells, which make it difficult to deduce the physiological role of endogenous GPR55. In the present study, we found that PC12 cells, a neural model cell line, express endogenous GPR55, and by using these cells, we were able to examine the role of endogenous GPR55. Although GPR55 mRNA and protein were expressed in PC12 cells, neither CB(1 nor CB(2 mRNA was expressed in these cells. GPR55 was predominantly localized on the plasma membrane in undifferentiated PC12 cells. However, GPR55 was also localized in the growth cones or the ruffled border in differentiated PC12 cells, suggesting a potential role for GPR55 in the regulation of neurite elongation. LPI increased intracellular Ca(2+ concentration and RhoA activity, and induced ERK1/2 phosphorylation, whereas endogenous and synthetic cannabinoids did not, thereby suggesting that cannabinoids are not GPR55 agonists. LPI also caused neurite retraction in a time-dependent manner accompanied by the loss of neurofilament light chain and redistribution of actin in PC12 cells differentiated by NGF. This LPI-induced neurite retraction was found to be G(q-independent and G(13-dependent. Furthermore, inactivation of RhoA function via C3 toxin and GPR55 siRNA knockdown prevented LPI-induced neurite retraction. These results suggest that LPI, and not cannabinoids, causes neurite retraction in differentiated PC12 cells via a GPR55, G(13 and RhoA signaling pathway.

  1. Effect of the Neck Retraction Taping (NRT) on Forward Head Posture and the Upper Trapezius Muscle during Computer Work

    OpenAIRE

    Yoo, Won-gyu

    2013-01-01

    [Purpose] The purpose of this study was to investigate the effect of neck retraction taping on forward head posture and the upper trapezius muscle of computer workers during computer work. [Subjects] Twelve males aged 20–30 years were recruited. [Methods] We measured forward head angle and upper trapezius muscle activity during computer work before and after NRT. [Results] The FHP angle significantly decreased during computer work performed with NRT compared to without NRT. The UT muscle acti...

  2. Retraction: Aydin, B. Statistical Convergent Topological Sequence Entropy Maps of the Circle. Entropy 2004, 6, 257–261

    Directory of Open Access Journals (Sweden)

    Kevin H. Knuth

    2014-02-01

    Full Text Available The editors were made aware that a paper published in Entropy in 2004 [1] may have plagiarized an earlier paper by Roman Hric published in 2000 [2]. After checking with specialized plagiarism software, we found that this claim is indeed correct and almost the entire paper is a verbatim copy of the earlier one. After confirmation of this fact, the editors of Entropy have decided to retract the paper immediately. [...

  3. MD 755: Instability threshold and tune shift study with reduced retraction between primary and secondary collimators in IR7

    CERN Document Server

    Carver, Lee Robert; Mereghetti, Alessio; Bruce, Roderik; Metral, Elias; Salvant, Benoit; Nisbet, David; Redaelli, Stefano; Salvachua Ferrando, Belen Maria; CERN. Geneva. ATS Department

    2016-01-01

    The purpose of this MD is to quantify in terms of stabilising octupole current threshold the impedance change when reducing the retraction between the primary and secondary collimators in IR7. This will be performed by first measuring the octupole current threshold required for stability with the tighter secondary collimator settings at 6.5 (w.r.t. to the nominal settings at 8 ), and then measuring the tune shift that occurs when the collimators are moved to the new settings.

  4. Pulmonary dendritic cells: thinking globally, acting locally

    OpenAIRE

    Randall, Troy D.

    2010-01-01

    The phrase “think globally, act locally” was coined in the early 1970s and directed individuals to clean up their local environment with the ultimate goal of improving the health of the entire planet. Several recent studies indicate that similar considerations apply to the immune system, in which small numbers of leukocytes, such as pulmonary dendritic cells, can modify the local immune environment in the lung and promote a positive outcome for the organism.

  5. Dendritic cells and aging: consequences for autoimmunity

    OpenAIRE

    Agrawal, Anshu; Sridharan, Aishwarya; Prakash, Sangeetha; Agrawal, Harsh

    2012-01-01

    The immune system has evolved to mount immune responses against foreign pathogens and to remain silent against self-antigens. A balance between immunity and tolerance is required as any disturbance may result in chronic inflammation or autoimmunity. Dendritic cells (DCs) actively participate in maintaining this balance. Under steady-state conditions, DCs remain in an immature state and do not mount an immune response against circulating self-antigens in the periphery, which maintains a state ...

  6. Plasmacytoid Dendritic Cells: From Heart to Vessels

    OpenAIRE

    Rosalinda Sorrentino; Silvana Morello; Aldo Pinto

    2010-01-01

    Cardiovascular diseases, formerly only attributed to the alterations of the stromal component, are now recognized as immune-based pathologies. Plasmacytoid Dendritic Cells (pDCs) are important immune orchestrators in heart and vessels. They highly produce IFN type I that promote the polarization of T cells towards a Th1 phenotype; however, pDCs can also participate to suppressive networks via the recruitment of T regulatory cells that downmodulate proinflammatory responses. pDCs populate the ...

  7. Harnessing dendritic cells in inflammatory skin diseases

    OpenAIRE

    Chu, Chung-Ching; di Meglio, Paola; Nestle, Frank O

    2011-01-01

    The skin immune system harbors a complex network of dendritic cells (DCs). Recent studies highlight a diverse functional specialization of skin DC subsets. In addition to generating cellular and humoral immunity against pathogens, skin DCs are involved in tolerogenic mechanisms to ensure the maintenance of immune homeostasis, as well as in pathogenesis of chronic inflammation in the skin when excessive immune responses are initiated and unrestrained. Harnessing DCs by directly targeting DC-de...

  8. Follicular dendritic cells in health and disease

    OpenAIRE

    El Shikh, Mohey Eldin M.; Costantino ePitzalis

    2012-01-01

    Follicular dendritic cells (FDCs) are unique immune cells that contribute to the regulation of humoral immune responses. These cells are located in the B cell follicles of secondary lymphoid tissues where they trap and retain antigens (Ags) in the form of highly immunogenic immune complexes (ICs) consisting of Ag plus specific antibody (Ab) and/or complement proteins. FDCs multimerise Ags and present them polyvalently to B cells in periodically arranged arrays that extensively crosslink the B...

  9. Follicular dendritic cells in health and disease

    OpenAIRE

    El Shikh, Mohey Eldin M.; Pitzalis, Costantino

    2012-01-01

    Follicular dendritic cells (FDCs) are unique immune cells that contribute to the regulation of humoral immune responses. These cells are located in the B-cell follicles of secondary lymphoid tissues where they trap and retain antigens (Ags) in the form of highly immunogenic immune complexes (ICs) consisting of Ag plus specific antibody (Ab) and/or complement proteins. FDCs multimerize Ags and present them polyvalently to B-cells in periodically arranged arrays that extensively crosslink the B...

  10. Role of Dendritic Cells in Immune Dysfunction

    Science.gov (United States)

    Savary, Cherylyn A.

    1997-01-01

    Specific aims include: (1) Application of the bioreactor to enhance cytokine-regulated proliferation and maturation of dendritic cells (DC); (2) Based on clues from spaceflight: compare the frequency and function of DC in normal donors and immunocompromised cancer patients; and (3) Initiate studies on the efficiency of cytokine therapy and DC-assisted immunotherapy (using bioreactor-expanded DC) in animal models of experimental fungal infections.

  11. SKIN DENDRITIC CELLS: ACTIVATION, MATURATION AND MIGRATION

    OpenAIRE

    Eaton, Laura

    2012-01-01

    Langerhans’ cells (LC) are the dendritic cells (DC) of the epidermis and, as sentinels of the immune system, act as a bridge between the innate and adaptive immune responses. When LC, and other DC, recognise an antigen or pathogen they mature and are stimulated to migrate to the lymph nodes, where they orchestrate immune responses. Pathogen derived toll-like receptor (TLR) ligands, and chemical allergens, are recognised as being potentially harmful and stimulate LC to mobilise and mature. Cyt...

  12. Bacterial Probiotic Modulation of Dendritic Cells

    OpenAIRE

    Drakes, Maureen; Blanchard, Thomas; Czinn, Steven

    2004-01-01

    Intestinal dendritic cells are continually exposed to ingested microorganisms and high concentrations of endogenous bacterial flora. These cells can be activated by infectious agents and other stimuli to induce T-cell responses and to produce chemokines which recruit other cells to the local environment. Bacterial probiotics are of increasing use against intestinal disorders such as inflammatory bowel disease. They act as nonpathogenic stimuli within the gut to regain immunologic quiescence. ...

  13. Imaging membrane potential in dendritic spines

    OpenAIRE

    Nuriya, Mutsuo; Jiang, Jiang; Nemet, Boaz; Eisenthal, Kenneth B.; Yuste, Rafael

    2006-01-01

    Dendritic spines mediate most excitatory inputs in the brain. Although it is clear that spines compartmentalize calcium, it is still unknown what role, if any, they play in integrating synaptic inputs. To investigate the electrical function of spines directly, we used second harmonic generation (SHG) imaging of membrane potential in pyramidal neurons from hippocampal cultures and neocortical brain slices. With FM 4-64 as an intracellular SHG chromophore, we imaged membrane potential in the so...

  14. The Isothermal Dendritic Growth Experiment Archive

    Science.gov (United States)

    Koss, Matthew

    2009-03-01

    The growth of dendrites is governed by the interplay between two simple and familiar processes---the irreversible diffusion of energy, and the reversible work done in the formation of new surface area. To advance our understanding of these processes, NASA sponsored a project that flew on the Space Shuttle Columbia is 1994, 1996, and 1997 to record and analyze benchmark data in an apparent-microgravity ``laboratory.'' In this laboratory, energy transfer by gravity driven convection was essentially eliminated and one could test independently, for the first time, both components of dendritic growth theory. The analysis of this data shows that although the diffusion of energy can be properly accounted for, the results from interfacial physics appear to be in disagreement and alternate models should receive increased attention. Unfortunately, currently and for the foreseeable future, there is no access or financial support to develop and conduct additional experiments of this type. However, the benchmark data of 35mm photonegatives, video, and all supporting instrument data are now available at the IDGE Archive at the College of the Holy Cross. This data may still have considerable relevance to researchers working specifically with dendritic growth, and more generally those working in the synthesis, growth & processing of materials, multiscale computational modeling, pattern formation, and systems far from equilibrium.

  15. Prospective intra-patient evaluation of a shoulder retraction device for radiotherapy in head and neck cancer

    International Nuclear Information System (INIS)

    Irradiation of tumors in the larynx and pharynx is often technically challenging in patients with a short neck or high shoulders. Shoulder retraction devices can sometimes resolve this problem and allow irradiation via lateral beam directions. This study aimed to measure the proportion of patients who would benefit from such an approach and to quantify the magnitude of the benefit obtained. Twenty patients were studied. Simulator images were obtained before and after intervention. The additional exposure of the cervical spine was measured. Patient comfort and acceptability were assessed with a questionnaire. Improvement of exposure of the cervical spine was observed in 80% of patients. In 20%, there was either no difference or the position was worse. Shoulder retraction exposed a mean of 8.4–10.2 mm more of the cervical spine. Patients in general reported the device as comfortable. The use of a shoulder retraction device produced clinically significant improvements in exposure of the tissues of the cervical spine and neck and should be considered in patients being irradiated for tumors arising in the larynx or hypopharynx.

  16. Neural pattern formation in networks with dendritic structure

    Science.gov (United States)

    Bressloff, P. C.; De Souza, B.

    1998-04-01

    We present a detailed analysis of a recently proposed model of neural pattern formation that is based on the combined effect of diffusion along a neuron's dendritic tree and recurrent interactions along axo-dendritic synaptic connections. For concreteness, we consider a one-dimensional array of analog neurons with the dendritic tree idealized as a one-dimensional cable. Linear stability analysis and bifurcation theory together with numerical simulations are used to establish conditions for the onset of a Turing instability leading to the formation of stable spatial patterns of network output activity. It is shown that the presence of dendritic structure can induce dynamic (time-periodic) spatial pattern formation. Moreover, correlations between the dendritic location of a synapse and the relative positions of neurons in the network are shown to result in spatially oscillating patterns of activity along the dendrites of each neuron.

  17. Molecular identity of dendritic voltage-gated sodium channels.

    Science.gov (United States)

    Lorincz, Andrea; Nusser, Zoltan

    2010-05-14

    Active invasion of the dendritic tree by action potentials (APs) generated in the axon is essential for associative synaptic plasticity and neuronal ensemble formation. In cortical pyramidal cells (PCs), this AP back-propagation is supported by dendritic voltage-gated Na+ (Nav) channels, whose molecular identity is unknown. Using a highly sensitive electron microscopic immunogold technique, we revealed the presence of the Nav1.6 subunit in hippocampal CA1 PC proximal and distal dendrites. Here, the subunit density is lower by a factor of 35 to 80 than that found in axon initial segments. A gradual decrease in Nav1.6 density along the proximodistal axis of the dendritic tree was also detected without any labeling in dendritic spines. Our results reveal the characteristic subcellular distribution of the Nav1.6 subunit, identifying this molecule as a key substrate enabling dendritic excitability. PMID:20466935

  18. Numerical Modeling of Dendrite Growth in Al Alloys

    Institute of Scientific and Technical Information of China (English)

    许庆彦; 柳百成

    2004-01-01

    Dendritic grains are the most often observed microstructure in metals and alloys. In the past decade, more and more attention has been paid to the modeling and simulation of dendritic microstructures. This paper describes a modified diffusion-limited aggregation model to simulate the complex shape of the dendrite grains during metal solidification. The fractal model was used to simulate equiaxed dendrite growth. The fractal dimensions of simulated Al alloy structures range from 1.63-1.88 which compares well with the experimentally-measured fractal dimension of 1.85; therefore, the model accurately predicts not only the dendritic structure morphology, but also the fractal dimension of the dendrite structure formed during solidification.

  19. Special fractal growth of dendrite copper using a hydrothermal method

    Science.gov (United States)

    Zheng, Yan; Zhang, Zhejuan; Guo, Pingsheng; He, Pingang; Sun, Zhuo

    2011-08-01

    Special fractal dendrite Cu nanostructures have been synthesized through a simple hydrothermal method, and the effects of the volume ratio between glycerol and water and the concentration of H 3PO 3 on the morphologies of dendrite Cu have been studied in detail. The Field emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM) and X-ray diffraction (XRD) have been used to characterize these Cu products. The results indicate that rhombic diamond and different morphologies of fractal dendrite were prepared because of the accumulation of Cu nuclei based on the diffusion-limited aggregation (DLA) and the nucleation-limited aggregation (NLA) model. Fortunately, symmetrical leaf-like dendrite Cu nanostructures different from Cu dendrites reported before have been obtained. Additionally, an explanation for the growth of fractal dendrite Cu has been discussed carefully.

  20. Retraction: Sophocleous, M. (2012). On understanding and predicting groundwater response time. Ground Water, 50: 528–540. doi: 10.1111/j.1745-6584.2011.00876.x.

    Science.gov (United States)

    2014-01-01

    The above article, published online on October 24, 2011 on Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the author's sponsoring institution, the journal Editor in Chief, Franklin W. Schwartz, and Wiley Periodicals, Inc. The retraction has been agreed following an investigation by the Kansas Geological Survey (a research and service division of the University of Kansas), which identified unattributed areas of overlap with a number of other publications. PMID:24754059

  1. Retraction notice to "Antimicrobial secondary metabolites from marine gastropod egg capsules and egg masses" [APJTB Volume 2 Issue 11(2012) 916-922

    Institute of Scientific and Technical Information of China (English)

    Kaviarasan; T; Siva; Sankar; R; Yogamoorthi; A

    2015-01-01

    <正>This article has been retracted:please see Elsevier Policy on Article Withdrawal(http://www.elsevier.com/locate/withdrawalpolicy).This article has been retracted at the request of the Editor-in-Chief and the First Author.Both the first author and the journal’s editor confirmed that Dr.A Yogamoorthi is not responsible for the plagiarism since his/her name was added without consent.

  2. Pathological Consequence of Misguided Dendritic Cell Differentiation in Histiocytic Diseases

    OpenAIRE

    Berres, Marie-Luise; Allen, Carl E.; Merad, Miriam

    2013-01-01

    Histiocytic disorders represent a group of complex pathologies characterized by the accumulation of histiocytes, an old term for tissue-resident macrophages and dendritic cells. Langerhans cell histiocytosis is the most frequent of histiocytosis in humans and has been thought to arise from the abnormal accumulation of epidermal dendritic cells called Langerhans cells. In this chapter, we discuss the origin and differentiation of Langerhans cells and dendritic cells and present accumulated evi...

  3. Murid herpesvirus-4 exploits dendritic cells to infect B cells

    OpenAIRE

    Miguel Gaspar; May, Janet S.; Soumi Sukla; Bruno Frederico; Michael B Gill; Smith, Christopher M.; Belz, Gabrielle T.; Stevenson, Philip G.

    2011-01-01

    Author Summary We detect invading viruses with dendritic cells and eliminate them with lymphocytes. A key interaction is lymphocyte activation by dendritic cells presenting viral antigens. Not all viruses can be eliminated, and some that persist deliberately colonize lymphocytes and dendritic cells, such that parasitism and host defence co-exist within the same sites. Once established, these infections are very hard to eliminate. Therefore to vaccinate against them we must determine how infec...

  4. Nanoparticle-aggregated 3D monocrystalline gold dendritic nanostructures

    International Nuclear Information System (INIS)

    In this paper, through a simple and fast electroless metal deposition route, gold dendritic nanostructures are synthesized in aqueous conditions. The gold dendrites with a threefold symmetric characteristic were built up of numerous nanoparticles roughly 5-10 nm in size. The aggregated nanoparticles spontaneously experience a self-assembly process along crystallographic orientations and finally form a monocrystalline dendrite. An oriented attachment mechanism can be used to explain the nanoparticle-aggregated self-assembly process

  5. CTAB-Influenced Electrochemical Dissolution of Silver Dendrites.

    Science.gov (United States)

    O'Regan, Colm; Zhu, Xi; Zhong, Jun; Anand, Utkarsh; Lu, Jingyu; Su, Haibin; Mirsaidov, Utkur

    2016-04-19

    Dendrite formation on the electrodes of a rechargeable battery during the charge-discharge cycle limits its capacity and application due to short-circuits and potential ignition. However, understanding of the underlying dendrite growth and dissolution mechanisms is limited. Here, the electrochemical growth and dissolution of silver dendrites on platinum electrodes immersed in an aqueous silver nitrate (AgNO3) electrolyte solution was investigated using in situ liquid-cell transmission electron microscopy (TEM). The dissolution of Ag dendrites in an AgNO3 solution with added cetyltrimethylammonium bromide (CTAB) surfactant was compared to the dissolution of Ag dendrites in a pure aqueous AgNO3 solution. Significantly, when CTAB was added, dendrite dissolution proceeded in a step-by-step manner, resulting in nanoparticle formation and transient microgrowth stages due to Ostwald ripening. This resulted in complete dissolution of dendrites and "cleaning" of the cell of any silver metal. This is critical for practical battery applications because "dead" lithium is known to cause short circuits and high-discharge rates. In contrast to this, in a pure aqueous AgNO3 solution, without surfactant, dendrites dissolved incompletely back into solution, leaving behind minute traces of disconnected silver particles. Finally, a mechanism for the CTAB-influenced dissolution of silver dendrites was proposed based on electrical field dependent binding energy of CTA(+) to silver. PMID:27017834

  6. Synaptically evoked dendritic action potentials in rat neocortical pyramidal neurons.

    Science.gov (United States)

    Schwindt, P C; Crill, W E

    1998-05-01

    In a previous study iontophoresis of glutamate on the apical dendrite of layer 5 pyramidal neurons from rat neocortex was used to identify sites at which dendritic depolarization evoked small, prolonged Ca2+ spikes and/or low-threshold Na+ spikes recorded by an intracellular microelectrode in the soma. These spikes were identified as originating in the dendrite. Here we evoke similar dendritic responses by electrical stimulation of presynaptic elements near the tip of the iontophoretic electrode with the use of a second extracellular electrode. In 9 of 12 recorded cells, electrically evoked excitatory postsynaptic potentials (EPSPs) above a minimum size triggered all-or-none postsynaptic responses similar to those evoked by dendritic glutamate iontophoresis at the same site. Both the synaptically evoked and the iontophoretically evoked depolarizations were abolished reversibly by blockade of glutamate receptors. In all recorded cells, the combination of iontophoresis and an EPSP, each of which was subthreshold for the dendritic spike when given alone, evoked a dendritic spike similar to that evoked by a sufficiently large iontophoresis. In one cell tested, dendritic spikes could be evoked by the summation of two independent subthreshold EPSPs evoked by stimulation at two different locations. We conclude that the dendritic spikes are not unique to the use of glutamate iontophoresis because similar spikes can be evoked by EPSPs. We discuss the implications of these results for synaptic integration and for the interpretation of recorded synaptic potentials. PMID:9582218

  7. Semi-solid Forming of a Damper Housing with Dendritic and Non-dendritic Al-Si-Mg Alloy

    Institute of Scientific and Technical Information of China (English)

    ChenCM; YangCC; ChaoCG

    2001-01-01

    A motorcycle component of damper housing was made by semi-solid forming process. This was used to investigate the effect of microstructures of feedstock on the formability of semisolid process. The soundness and microstructures of casting parts made by dendritic and non-dendritic feedstock were investigated. Separating of liquid phase was found in the casting produced by dendritic feedstock, which might result in defects of porosity, while uniform microstructures were found in the casting produced by no...

  8. At immature mossy fibers-CA3 connections, activation of presynaptic GABAB receptors by endogenously released GABA contributes to synapses silencing

    Directory of Open Access Journals (Sweden)

    Victoria F Safiulina

    2009-02-01

    Full Text Available Early in postnatal life correlated GABAergic activity in the hippocampus is thought to play a crucial role in synaptogenesis and in the development of adult neuronal networks. Unlike adulthood, at this developmental stage, mossy fibers (MF which are the axons of granule cells, release GABA into CA3 principal cells and interneurons. Here, we tested the hypothesis that at MF-CA3 connections, tonic activation of GABAB autoreceptors by GABA is responsible for the low probability of release and synapse silencing. Blocking GABAB receptors with CGP55845 enhanced the probability of GABA release and switched on silent synapses while the opposite was observed with baclofen. Both these effects were presynaptic and were associated with changes in paired-pulse ratio and coefficient of variation. In addition, enhancing the extracellular GABA concentration by repetitive stimulation of MF or by blocking the GABA transporter GAT-1, switched off active synapses, an effect that was prevented by CGP55845. In the presence of CGP55845, stimulation of MF induced synaptic potentiation. The shift of EGABA from the depolarizing to the hyperpolarizing direction with bumetanide, a blocker of the cation-chloride co-transporter NKCC1, prevented synaptic potentiation and caused synaptic depression, suggesting that the depolarizing action of GABA observed in the presence of CGP55845 is responsible for the potentiating effect. It is proposed that, activation of GABAB receptors by spillover of GABA from MF terminals reduces the probability of release and contributes to synapses silencing. This would act as a filter to prevent excessive activation of the auto-associative CA3 network and the emergence of seizures.

  9. Expression of c-Fos protein in medial septum/diagonal band of Broca and CA3 region, associated with the temporary inactivation of the supramammillary area.

    Science.gov (United States)

    Aranda, Lourdes

    2016-07-01

    The supramammillary (SuM) area is part of the diencephalic nuclei comprising the mammillary bodies, and is a key structure in the memory and spatial learning processes. It is a critical region in the modulation/generation of hippocampal theta rhythm. In addition, many papers have recently shown a clear involvement of this structure in the processes of spatial learning and memory in animal models, although it is still not known how it modulates spatial navigation and response emotional. The aim of the present research was to study the effect of the temporary inactivation of the SuM area on synaptic plasticity of crucial structures in the formation of spatial memory and emotional response. Sprague-Dawley rats were asigned in three groups: a control group where the animals were not subjected to any treatment, and two groups where the rats received microinjections of tetrodotoxin (TTX) in the SuM area (5ng diluted in 0.5μl of saline) or saline (0.5μl). The microinjections were administered 90min before the perfusion. Later, cellular activity in medial septum/diagonal band of Broca (MS/DBB) and CA3 region of the dorsal hippocampus was assessed, by measuring the immediate early gene c-fos. The results show a clear hiperactivity cellular in medial septum/diagonal band of Broca and a clear hypoactivity cellular in the CA3 region of the hippocampus when there was a functional inactivation of the SuM area. It suggests that the SuM area seems to be part of the connection and information input pathways to CA3 region of the hippocampal formation, key for proper functioning in spatial memory and emotional response. PMID:26802745

  10. Effect of tolbutamide, glyburide and glipizide administered supraspinally on CA3 hippocampal neuronal cell death and hyperglycemia induced by kainic acid in mice.

    Science.gov (United States)

    Kim, Chea-Ha; Park, Soo-Hyun; Sim, Yun-Beom; Kim, Sung-Su; Kim, Su-Jin; Lim, Su-Min; Jung, Jun-Sub; Suh, Hong-Won

    2014-05-20

    Sulfonylureas are widely used oral drugs for the treatment of type II diabetes mellitus. In the present study, the effects of sulfonylureas administered supraspinally on kainic acid (KA)-induced hippocampal neuronal cell death and hyperglycemia were studied in ICR mice. Mice were pretreated intracerebroventricularly (i.c.v.) with 30μg of tolbutamide, glyburide or glipizide for 10min and then, mice were administered i.c.v. with KA (0.1μg). The neuronal cell death in the CA3 region in the hippocampus was assessed 24h after KA administration and the blood glucose level was measured 30, 60, and 120min after KA administration. We found that i.c.v. pretreatment with tolbutamide, glyburide or glipizide attenuated the KA-induced neuronal cell death in CA3 region of the hippocampus and hyperglycemia. In addition, KA administered i.c.v. caused an elevation of plasma corticosterone level and a reduction of the plasma insulin level. The i.c.v. pretreatment with tolbutamide, glyburide or glipizide attenuated KA-induced increase of plasma corticosterone level. Furthermore, i.c.v. pretreatment with tolbutamide, glyburide or glipizide causes an elevation of plasma insulin level. Glipizide, but not tolbutamide or glyburide, pretreated i.c.v. caused a reversal of KA-induced hypoinsulinemic effect. Our results suggest that supraspinally administered tolbutamide, glyburide and glipizide exert a protective effect against KA-induced neuronal cells death in CA3 region of the hippocampus. The neuroprotective effect of tolbutamide, glyburide and glipizide appears to be mediated by lowering the blood glucose level induced by KA. PMID:24713348

  11. Aging Impairs the Late Phase of Long-Term Potentiation at the Medial Perforant Path-CA3 Synapse in Awake Rats

    OpenAIRE

    Dieguez, Dario; Barea-Rodriguez, Edwin J.

    2004-01-01

    The effects of aging on long-term potentiation (LTP) in the dentate gyrus (DG) and CA1 are well documented, but LTP at the medial perforant path (MPP)-CA3 synapse of aged animals has remained unexplored. Because the MPP-DG and Schaffer-collateral-CA1 synapses account for only about 20% of total hippocampal synapses, global understanding of how aging affects hippocampal plasticity has remained limited. Much is known about LTP induction in the hippocampal formation, whereas the mechanisms that ...

  12. Sub-80 femtosecond pulses generation from a diode-pumped mode-locked Nd:Ca3La2(BO3)4 disordered crystal laser.

    Science.gov (United States)

    Ma, Jie; Pan, Zhongben; Cai, Huaqiang; Yu, Haohai; Zhang, Huaijin; Shen, Deyuan; Tang, Dingyuan

    2016-04-01

    We experimentally demonstrated a diode-pumped sub-80 fs Nd:Ca3La2(BO3)4 disordered crystal laser. Pumping by an 808 nm fiber coupled laser diode, stable continuous-wave mode-locked pulses as short as 79 fs were achieved with a semiconductor saturable absorber mirror (SESAM). The ultrashort pulses had a repetition rate of ∼98.9  MHz at the central wavelength of about 1068 nm. To the best of our knowledge, this is the first demonstration of sub-100 fs pulses and the shortest mode-locked pulses generated from the Nd3+-doped crystal lasers. PMID:27192242

  13. Analyses of stable isotopes in camelids collagen bones from Tulan Ravine, Atacama Puna, early formative period (CA 3,1000-2,400BP)

    International Nuclear Information System (INIS)

    This paper presents the results of isotope analysis (δ13C y δ15N) conducted on bone collagen found in Lama guanicoe and Lama glama remains from Tulan-85 and Tulan-54 archaeological sites. Both sites have been dated to the Early Formative Period (ca. 3,100-2,400 ap) and are located southeast of the Atacama Puna basin. Faunal samples were selected using anatomical and morphometric criteria. The results indicate divergences in the diets of both species, reflecting vegetation variation in the Tulan Quebrada caused by altitude differences and linked to hunting and herding areas

  14. Evidence for the coexistence of low-dimensional magnetism and long-range order in Ca3CoRhO6

    OpenAIRE

    Loewenhaupt, M.; Schaefer, W.; Niazi, A.; Sampathkumaran, E. V.

    2003-01-01

    We report the results of neutron powder diffraction studies on the spin-chain compound Ca3CoRhO6 in the temperature range 3 to 293 K. Bragg peaks due to magnetic ordering start appearing below about 100 K. The most interesting observation is that there is a diffuse magnetic peak superimposed over the strongest magnetic Bragg peak. The diffuse magnetic intensity is observed below as well above 100 K. This finding provides a new insight into the physics of this compound as though the low-dimens...

  15. mGluR2 acts through inhibitory Gα subunits to regulate transmission and long-term plasticity at hippocampal mossy fiber-CA3 synapses

    OpenAIRE

    Nicholls, Russell E.; ZHANG, XIAO-LEI; Bailey, Christopher P.; Conklin, Bruce R; Kandel, Eric R.; Stanton, Patric K.

    2006-01-01

    Presynaptic inhibitory G protein-coupled receptors play a critical role in regulating transmission at a number of synapses in the central and peripheral nervous system. We generated transgenic mice that express a constitutively active form of an inhibitory Gα subunit to examine the molecular mechanisms underlying the actions of one such receptor, metabotropic glutamate receptor (mGluR) 2, at mossy fiber-CA3 synapses in the hippocampus. mGluR2 participates in at least three types of mossy fibe...

  16. Effects of movement training on synaptic interface structure in the sensorimotor cortex and hippocampal CA3 area of the ischemic hemisphere in cerebral infarction rats

    Institute of Scientific and Technical Information of China (English)

    Min Yang; Jiyan Cheng

    2008-01-01

    BACKGROUND: Movement is an effective way to provide sensory, movement and reflectivity afferent stimulation to the central nervous system. Movement plays an important role in functional recombination and compensation in the brain. OBJECTIVE: To observe movement training effects on texture parameters of synaptic interfaces in the sensorimotor cortex and hippocampal CA3 area of the ischemic hemisphere and on motor function in cerebral infarction rats. DESIGN, TIME AND SETTING: This neural morphology and pathology randomized controlled animal experiment was performed at the Center Laboratory, Affiliated Hospital of Luzhou Medical College, China from November 2004 to April 2005. MATERIALS: A total of 32 healthy male Wistar rats aged 8 weeks were equally and randomly assigned into model and movement training groups. METHODS: Rat models of right middle cerebral artery occlusion were established using the suture occlusion method in both groups. Rats in the movement training group underwent balance training, screen training, and rotating rod training starting on day 5 after surgery, for 40 minutes every day, 6 days per week, for 4 weeks. MAIN OUTCOME MEASURES: Texture parameters of synaptic interfaces were determined using a transmission electron microscope and image analyzer during week 5 following model induction. The following parameters were measured: synaptic cleft width; postsynaptic density thickness; synaptic interface curvature; and active zone length. Motor function was assessed using balance training, screen training, and rotating rod training. The lower score indicated a better motor function. RESULTS: The postsynaptic density thickness, synaptic interface curvature, and active zone length were significantly increased in the sensorimotor cortex and hippocampal CA3 area of the ischemic hemisphere of rats from the movement training group compared with the model group (P < 0.05 or 0.01). Curved synapses and perforated synapses were seen in the sensorimotor cortex

  17. Kinetic arrest of field-temperature induced first order phase transition in quasi-one dimensional spin system Ca3Co2O6

    Science.gov (United States)

    De, Santanu; Kumar, Kranti; Banerjee, A.; Chaddah, P.

    2016-05-01

    We have found that the geometrically frustrated spin chain compound Ca3Co2O6 belonging to Ising like universality class with uniaxial anisotropy shows kinetic arrest of first order intermediate phase (IP) to ferrimagnetic (FIM) transition. In this system, dc magnetization measurements followed by different protocols suggest the coexistence of high temperature IP with equilibrium FIM phase in low temperature. Formation of metastable state due to hindered first order transition has also been probed through cooling and heating in unequal field (CHUF) protocol. Kinetically arrested high temperature IP appears to persist down to almost the spin freezing temperature in this system.

  18. SCRAPPER regulates the thresholds of long-term potentiation/depression, the bidirectional synaptic plasticity in hippocampal CA3-CA1 synapses.

    Science.gov (United States)

    Takagi, Hiroshi; Setou, Mitsutoshi; Ito, Seiji; Yao, Ikuko

    2012-01-01

    SCRAPPER, which is an F-box protein encoded by FBXL20, regulates the frequency of the miniature excitatory synaptic current through the ubiquitination of Rab3-interacting molecule 1. Here, we recorded the induction of long-term potentiation/depression (LTP/LTD) in CA3-CA1 synapses in E3 ubiquitin ligase SCRAPPER-deficient hippocampal slices. Compared to wild-type mice, Scrapper-knockout mice exhibited LTDs with smaller magnitudes after induction with low-frequency stimulation and LTPs with larger magnitudes after induction with tetanus stimulation. These findings suggest that SCRAPPER regulates the threshold of bidirectional synaptic plasticity and, therefore, metaplasticity. PMID:23316391

  19. SCRAPPER Regulates the Thresholds of Long-Term Potentiation/Depression, the Bidirectional Synaptic Plasticity in Hippocampal CA3-CA1 Synapses

    OpenAIRE

    Hiroshi Takagi; Mitsutoshi Setou; Seiji Ito; Ikuko Yao

    2012-01-01

    SCRAPPER, which is an F-box protein encoded by FBXL20, regulates the frequency of the miniature excitatory synaptic current through the ubiquitination of Rab3-interacting molecule 1. Here, we recorded the induction of long-term potentiation/depression (LTP/LTD) in CA3-CA1 synapses in E3 ubiquitin ligase SCRAPPER-deficient hippocampal slices. Compared to wild-type mice, Scrapper-knockout mice exhibited LTDs with smaller magnitudes after induction with low-frequency stimulation and LTPs with la...

  20. SCRAPPER Regulates the Thresholds of Long-Term Potentiation/Depression, the Bidirectional Synaptic Plasticity in Hippocampal CA3-CA1 Synapses

    Directory of Open Access Journals (Sweden)

    Hiroshi Takagi

    2012-01-01

    Full Text Available SCRAPPER, which is an F-box protein encoded by FBXL20, regulates the frequency of the miniature excitatory synaptic current through the ubiquitination of Rab3-interacting molecule 1. Here, we recorded the induction of long-term potentiation/depression (LTP/LTD in CA3-CA1 synapses in E3 ubiquitin ligase SCRAPPER-deficient hippocampal slices. Compared to wild-type mice, Scrapper-knockout mice exhibited LTDs with smaller magnitudes after induction with low-frequency stimulation and LTPs with larger magnitudes after induction with tetanus stimulation. These findings suggest that SCRAPPER regulates the threshold of bidirectional synaptic plasticity and, therefore, metaplasticity.

  1. Studies on the new superconducting system (RE) Ba2Ca3Sr4Cu5Ox (RE=Gd, Ho & Dy)

    Science.gov (United States)

    Arumugam, S.

    1996-03-01

    Superconducting studies have been carried out in the new high TC (50-65K) system (RE)Ba2Ca3Sr4Cu5OX [(RE) 12345] with RE=Gd, Ho&Dy. The unit cell dimensions are of the order of a=5.44 °A, b=5.46°A and c=14.62°A. The data above the diamagnetic onset and below the upturn temperature due to ordering were analyzed to yield the effective magnetic moments (Peff) of the rare earth ions.

  2. Crystal Growth of Ca3Nb(Ga1−xAlx)3Si2O14 Piezoelectric Single Crystals with Various Al Concentrations

    OpenAIRE

    Yuui Yokota; Tetsuo Kudo; Yuji Ohashi; Andrey Medvedev; Shunsuke Kurosawa; Kei Kamada; Akira Yoshikawa

    2015-01-01

    Ca3Nb(Ga1−xAlx)3Si2O14 (CNGAS) single crystals with various Al concentrations were grown by a micro-pulling-down (µ-PD) method and their crystal structures, chemical compositions, crystallinities were investigated. CNGAS crystals with x = 0.2, 0.4 and 0.6 indicated a single phase of langasite-type structure without any secondary phases. In contrast, the crystals with x = 0.8 and 1 included some secondary phases in addition to the langasite-type phase. Lattice parameters, a- and c-axes lengths...

  3. Effects of unpredictable chronic stress on behavior and brain-derived neurotrophic factor expression in CA3 subfield and dentate gyrus of the hippocampus in different aged rats

    Institute of Scientific and Technical Information of China (English)

    LI Ying; JI Yong-juan; JIANG Hong; LIU De-xiang; ZHANG Qian; FAN Shu-jian; PAN Fang

    2009-01-01

    Background Brain-derived neurotrophic factor (BDNF) is a stress-responsive intercellular messenger modifying hypothalamic-pituitary-adrenal (HPA) axis activity. The interaction between stress and age in BDNF expression is currently not fully understood. This study was conducted to observe unpredictable stress effect on behavior and BDNF expression in CA3 subfield (CA3) and dentate gyrus of hippocampus in different aged rats. Methods Forty-eight Wistar rats of two different ages (2 months and 15 months) were randomly assigned to six groups: two control groups and four stress groups. The rats in the stress group received three weeks of unpredictable mild stress. The depression state and the stress level of the animals were determined by sucrose preference test and observation of exploratory behavior in an open field (OF) test. The expressions of BDNF in CA3 and dentate gyrus of the hippocampus were measured using immunohistochemistry. Results Age and stress had different effects on the behavior of different aged animals (age: F=6.173, P <0.05, stress: F=6.056, P <0.05). Stress was the main factor affecting sucrose preference (F=123.608, P <0.05). Decreased sucrose preference and suppressed behavior emerged directly following stress, lasting to at least the eighth day after stress in young animals (P <0.05). The older stress rats showed a lower sucrose preference than young stress rats (P <0.05). Older control rats behaved differently from the younger control animals in the OF test, spending more time in the central square (P <0.05), exhibiting fewer vertical movements (P <0.05) and less grooming (P <0.05). Following exposure to stress, older-aged rats showed no obvious changes in vertical movement and grooming. This indicates that aged rats were in an unexcited state before the stress period, and responded less to stressful stimuli than younger rats. There was significantly lower BDNF expression in the CA3 and dentate gyrus regions of the hippocampus following stress

  4. NONLINEAR OPTICAL PHENOMENA: Stimulated Raman scattering of picosecond pulses in SrMoO4 and Ca3(VO4)2 crystals

    Science.gov (United States)

    Zverev, Petr G.; Karasik, Aleksandr Ya; Basiev, Tasoltan T.; Ivleva, Lyudmila I.; Osiko, Vyacheslav V.

    2003-04-01

    An express technique is proposed for the study of stimulated Raman scattering (SRS) in crystals excited by long trains of picosecond pulses. SRS was studied in several crystals excited by 15-ps pulses from an Nd3+:CLNGG disordered garnet laser. SRS in SrMoO4 and Ca3(VO4)2 crystals was obtained and investigated for the first time, and compared with SRS in popular SRS-active BaWO4 and KGd(WO4)2 crystals.

  5. Synthesis and physical properties of (Cu,M)Ba2Ca3Cu4Oz (M = C,Mg,Ni,Al,Zn,Tl)

    International Nuclear Information System (INIS)

    The authors have synthesized the single phase samples of CuxC0.1Ba2Ca3Cu4Oz (x = 0.2∼0.9). Transport and magnetic measurements and iodometric titration analysis were carried out for these materials. From these results they discuss the correlation between Tc, the Hall number, copper valence and oxygen content. The effect of the substituted M ions on Tc in (CuC, M)-1234 (M = Ni,Zn,Al,Tl,Mg) is also discussed. They propose a unique selective carrier-doping mechanism in (Cu,C)- and (CuC, Mg)-1234 systems

  6. Ternary eutectic dendrites: Pattern formation and scaling properties

    Energy Technology Data Exchange (ETDEWEB)

    Rátkai, László; Szállás, Attila; Pusztai, Tamás [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, P.O. Box 49, H-1525 Budapest (Hungary); Mohri, Tetsuo [Center for Computational Materials Science, Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Gránásy, László, E-mail: granasy.laszlo@wigner.mta.hu [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, P.O. Box 49, H-1525 Budapest (Hungary); Brunel University, Uxbridge, Middlesex UB8 3PH (United Kingdom)

    2015-04-21

    Extending previous work [Pusztai et al., Phys. Rev. E 87, 032401 (2013)], we have studied the formation of eutectic dendrites in a model ternary system within the framework of the phase-field theory. We have mapped out the domain in which two-phase dendritic structures grow. With increasing pulling velocity, the following sequence of growth morphologies is observed: flat front lamellae → eutectic colonies → eutectic dendritesdendrites with target pattern → partitionless dendrites → partitionless flat front. We confirm that the two-phase and one-phase dendrites have similar forms and display a similar scaling of the dendrite tip radius with the interface free energy. It is also found that the possible eutectic patterns include the target pattern, and single- and multiarm spirals, of which the thermal fluctuations choose. The most probable number of spiral arms increases with increasing tip radius and with decreasing kinetic anisotropy. Our numerical simulations confirm that in agreement with the assumptions of a recent analysis of two-phase dendrites [Akamatsu et al., Phys. Rev. Lett. 112, 105502 (2014)], the Jackson-Hunt scaling of the eutectic wavelength with pulling velocity is obeyed in the parameter domain explored, and that the natural eutectic wavelength is proportional to the tip radius of the two-phase dendrites. Finally, we find that it is very difficult/virtually impossible to form spiraling two-phase dendrites without anisotropy, an observation that seems to contradict the expectations of Akamatsu et al. Yet, it cannot be excluded that in isotropic systems, two-phase dendrites are rare events difficult to observe in simulations.

  7. Ternary eutectic dendrites: Pattern formation and scaling properties

    International Nuclear Information System (INIS)

    Extending previous work [Pusztai et al., Phys. Rev. E 87, 032401 (2013)], we have studied the formation of eutectic dendrites in a model ternary system within the framework of the phase-field theory. We have mapped out the domain in which two-phase dendritic structures grow. With increasing pulling velocity, the following sequence of growth morphologies is observed: flat front lamellae → eutectic colonies → eutectic dendritesdendrites with target pattern → partitionless dendrites → partitionless flat front. We confirm that the two-phase and one-phase dendrites have similar forms and display a similar scaling of the dendrite tip radius with the interface free energy. It is also found that the possible eutectic patterns include the target pattern, and single- and multiarm spirals, of which the thermal fluctuations choose. The most probable number of spiral arms increases with increasing tip radius and with decreasing kinetic anisotropy. Our numerical simulations confirm that in agreement with the assumptions of a recent analysis of two-phase dendrites [Akamatsu et al., Phys. Rev. Lett. 112, 105502 (2014)], the Jackson-Hunt scaling of the eutectic wavelength with pulling velocity is obeyed in the parameter domain explored, and that the natural eutectic wavelength is proportional to the tip radius of the two-phase dendrites. Finally, we find that it is very difficult/virtually impossible to form spiraling two-phase dendrites without anisotropy, an observation that seems to contradict the expectations of Akamatsu et al. Yet, it cannot be excluded that in isotropic systems, two-phase dendrites are rare events difficult to observe in simulations

  8. CTLA-4 blockade during dendritic cell based booster vaccination influences dendritic cell survival and CTL expansion

    DEFF Research Database (Denmark)

    Pedersen, Anders E; Ronchese, Franca

    2007-01-01

    Dendritic cells (DCs) are potent antigen-presenting cells and critical for the priming of CD8+ T cells. Therefore the use of these cells as adjuvant cells has been tested in a large number of experimental and clinical vaccination studies, in particular cancer vaccine studies. A number of protocols...

  9. 回缩性睾丸的临床研究%Long term follow-up results of testicular retraction

    Institute of Scientific and Technical Information of China (English)

    郭祥; 李爽; 王军; 郭晖; 雷伟; 李刚; 马慧; 杨春雷; 程银涛

    2014-01-01

    目的:通过评价回缩性睾丸患睾临床转归时间为临床治疗回缩性睾丸提供参考。方法回顾性分析了本院40例2004年3月至2009年9月被诊断为回缩睾丸的患儿,所有的患儿在随访时评价睾丸收缩性、位置、睾丸体积,并根据随访结果分为回缩组、正常组、固定组。结果40个患儿,21例单侧回缩睾丸(52.5%),19双侧回缩睾丸(47.5%)。他们的平均年龄为(3±2.7)岁,评价随访时间为(4.1±1.6)年。59例回缩睾丸,27例(45.7%)成功降入阴囊,23例(39.0%)保持回缩,9例患者(15.3%)为睾丸未降或睾丸体积变小行睾丸固定术。40例患者中平均随访(4.4±1.7)年。正常组平均随访时间为(4.1±1.3)年,回缩组平均随访时间为(5.2±1.7)年,固定组平均随访时间为(3.7±1.6)年。正常组平均诊断年龄为(4.3±3.2)年,回缩组平均诊断年龄为(2.3±1.6)年,固定组平均诊断年龄(1.3±0.8)年。固定组与正常组相比较,固定组平均诊断年龄小于正常组的平均诊断年龄(P <0.05)。结论回缩性睾丸有需行外科睾丸固定术的干预的风险,且年龄越小被诊断为回缩性睾丸的患者有需行外科睾丸固定术干预的风险越高。%Objective To make a reference for clinical surgery operation intervention of retractile testis through long-term follow-up of testisvolume and position. Methods A retrospective analysis of 40 cases in our hospital diagnosed with testicular retraction was carried out in the study. According to the follow-up results of testicular shrinkage, position and testicular volume, the patients were divided into the retraction group, the normal group, the fixed group. Results Of 40 patients, 21 cases had unilateral testicular retraction (52.5%), 19 (47.5%) had bilateral testicular retraction. Their average age was (3±2.7)years, evaluation and follow-up was (4.1±1.6)years. Among 59 cases

  10. Dendritic cells modified by vitamin D

    DEFF Research Database (Denmark)

    Pedersen, Ayako Wakatsuki; Claesson, Mogens Helweg; Zocca, Mai-Britt

    2011-01-01

    Dendritic cells (DCs), the most potent antigen-presenting cells of the immune system, express nuclear receptors for 1,25-dihydroxyvitamin D(3) (VD3) and they are one of its main targets. In the presence of VD3, DCs differentiate into a phenotype that resembles semimature DCs, with reduced T cell...... costimulatory molecules and hampered IL-12 production. These VD3-modulated DCs induce T cell tolerance in vitro using multiple mechanisms such as rendering T cells anergic, dampening of Th1 responses, and recruiting and differentiating regulatory T cells. Due to their ability to specifically target pathological...

  11. Buoyancy effects of a growing, isolated dendrite

    Science.gov (United States)

    Canright, D.; Davis, S. H.

    1991-01-01

    The buoyancy effect of a growing isolated dendrite on the solidification process in the undercooling liquid material was investigated by developing an analytic solution to the growth/convection problem in powers of a buoyancy parameter G. The solution depends on the Prandtl number P and the Stefan number S (undercooling) for the local velocity and thermal fields and also the buoyant alteration of the interface shape. Results suggest that buoyancy effect for metals (low P) may be qualitatively different from that for organics (high P).

  12. Plasticity of dendritic spines: subcompartmentalization of signaling.

    Science.gov (United States)

    Colgan, Lesley A; Yasuda, Ryohei

    2014-01-01

    The ability to induce and study neuronal plasticity in single dendritic spines has greatly advanced our understanding of the signaling mechanisms that mediate long-term potentiation. It is now clear that in addition to compartmentalization by the individual spine, subcompartmentalization of biochemical signals occurs at specialized microdomains within the spine. The spatiotemporal coordination of these complex cascades allows for the concomitant remodeling of the postsynaptic density and actin spinoskeleton and for the regulation of membrane traffic to express functional and structural plasticity. Here, we highlight recent findings in the signaling cascades at spine microdomains as well as the challenges and approaches to studying plasticity at the spine level. PMID:24215443

  13. Gliadin fragments promote migration of dendritic cells

    Czech Academy of Sciences Publication Activity Database

    Chládková, Barbara; Kamanová, Jana; Palová-Jelínková, Lenka; Cinová, Jana; Šebo, Peter; Tučková, Ludmila

    2011-01-01

    Roč. 15, č. 4 (2011), 938-948. ISSN 1582-1838 R&D Projects: GA ČR GA310/07/0414; GA ČR GD310/08/H077; GA ČR GA310/08/0447; GA AV ČR IAA500200801; GA AV ČR IAA500200914 Institutional research plan: CEZ:AV0Z50200510 Keywords : celiac disease * gliadin * dendritic cell Subject RIV: EC - Immunology Impact factor: 4.125, year: 2011

  14. Organization of TNIK in dendritic spines.

    Science.gov (United States)

    Burette, Alain C; Phend, Kristen D; Burette, Susan; Lin, Qingcong; Liang, Musen; Foltz, Gretchen; Taylor, Noël; Wang, Qi; Brandon, Nicholas J; Bates, Brian; Ehlers, Michael D; Weinberg, Richard J

    2015-09-01

    Tumor necrosis factor receptor-associated factor 2 (TRAF2)- and noncatalytic region of tyrosine kinase (NCK)-interacting kinase (TNIK) has been identified as an interactor in the psychiatric risk factor, Disrupted in Schizophrenia 1 (DISC1). As a step toward deciphering its function in the brain, we performed high-resolution light and electron microscopic immunocytochemistry. We demonstrate here that TNIK is expressed in neurons throughout the adult mouse brain. In striatum and cerebral cortex, TNIK concentrates in dendritic spines, especially in the vicinity of the lateral edge of the synapse. Thus, TNIK is highly enriched at a microdomain critical for glutamatergic signaling. PMID:25753355

  15. Metamaterial absorber with random dendritic cells

    Science.gov (United States)

    Zhu, Weiren; Zhao, Xiaopeng

    2010-05-01

    The metamaterial absorber composed of random dendritic cells has been investigated at microwave frequencies. It is found that the absorptivities come to be weaker and the resonant frequency get red shift as the disordered states increasing, however, the random metamaterial absorber still presents high absorptivity more than 95%. The disordered structures can help understanding of the metamaterial absorber and may be employed for practical design of infrared metamaterial absorber, which may play important roles in collection of radiative heat energy and directional transfer enhancement.

  16. Harnessing Dendritic Cells for Tumor Antigen Presentation

    International Nuclear Information System (INIS)

    Dendritic cells (DC) are professional antigen presenting cells that are crucial for the induction of anti-tumor T cell responses. As a consequence, research has focused on the harnessing of DCs for therapeutic interventions. Although current strategies employing ex vivo-generated and tumor-antigen loaded DCs have been proven feasible, there are still many obstacles to overcome in order to improve clinical trial successes and offset the cost and complexity of customized cell therapy. This review focuses on one of these obstacles and a pivotal step for the priming of tumor-specific CD8+ and CD4+ T cells; the in vitro loading of DCs with tumor antigens

  17. Viruses, dendritic cells and the lung

    Directory of Open Access Journals (Sweden)

    Graham Barney S

    2001-06-01

    Full Text Available Abstract The interaction between viruses and dendritic cells (DCs is varied and complex. DCs are key elements in the development of a host response to pathogens such as viruses, but viruses have developed survival tactics to either evade or diminish the immune system that functions to kill and eliminate these micro-organisms. In the present review we summarize current concepts regarding the function of DCs in the immune system, our understanding of how viruses alter DC function to attenuate both the virus-specific and global immune response, and how we may be able to exploit DC function to prevent or treat viral infections.

  18. Measles Virus Induces Functional TRAIL Production by Human Dendritic Cells

    Science.gov (United States)

    Vidalain, Pierre-Olivier; Azocar, Olga; Lamouille, Barbara; Astier, Anne; Rabourdin-Combe, Chantal; Servet-Delprat, Christine

    2000-01-01

    Measles virus infection induces a profound immunosuppression that can lead to serious secondary infections. Here we demonstrate that measles virus induces tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) mRNA and protein expression in human monocyte-derived dendritic cells. Moreover, measles virus-infected dendritic cells are shown to be cytotoxic via the TRAIL pathway. PMID:10590149

  19. Measles Virus Induces Functional TRAIL Production by Human Dendritic Cells

    OpenAIRE

    Vidalain, Pierre-Olivier; Azocar, Olga; Lamouille, Barbara; Astier, Anne; Rabourdin-Combe, Chantal; Servet-Delprat, Christine

    2000-01-01

    Measles virus infection induces a profound immunosuppression that can lead to serious secondary infections. Here we demonstrate that measles virus induces tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) mRNA and protein expression in human monocyte-derived dendritic cells. Moreover, measles virus-infected dendritic cells are shown to be cytotoxic via the TRAIL pathway.

  20. Dendritic Spines in Depression: What We Learned from Animal Models

    OpenAIRE

    Hui Qiao; Ming-Xing Li; Chang Xu; Hui-Bin Chen; Shu-Cheng An; Xin-Ming Ma

    2016-01-01

    Depression, a severe psychiatric disorder, has been studied for decades, but the underlying mechanisms still remain largely unknown. Depression is closely associated with alterations in dendritic spine morphology and spine density. Therefore, understanding dendritic spines is vital for uncovering the mechanisms underlying depression. Several chronic stress models, including chronic restraint stress (CRS), chronic unpredictable mild stress (CUMS), and chronic social defeat stress (CSDS), have ...

  1. Contribution of sublinear and supralinear dendritic integration to neuronal computations

    Directory of Open Access Journals (Sweden)

    Alexandra eTran-Van-Minh

    2015-03-01

    Full Text Available Nonlinear dendritic integration is thought to increase the computational ability of neurons. Most studies focus on how supralinear summation of excitatory synaptic responses arising from clustered inputs within single dendrites result in the enhancement of neuronal firing, enabling simple computations such as feature detection. Recent reports have shown that sublinear summation is also a prominent dendritic operation, extending the range of subthreshold input-output transformations conferred by dendrites. Like supralinear operations, sublinear dendritic operations also increase the repertoire of neuronal computations, but feature extraction requires different synaptic connectivity strategies for each of these operations. In this article we will review the experimental and theoretical findings describing the biophysical determinants of the three primary classes of dendritic operations: linear, sublinear, and supralinear. We then review a Boolean algebra-based analysis of simplified neuron models, which provides insight into how dendritic operations influence neuronal computations. We highlight how neuronal computations are critically dependent on the interplay of dendritic properties (morphology and voltage-gated channel expression, spiking threshold and distribution of synaptic inputs carrying particular sensory features. Finally, we describe how global (scattered and local (clustered integration strategies permit the implementation of similar classes of computations, one example being the object feature binding problem.

  2. Comparison of the clinical effects of electrosurgical retraction and cord gingival retraction%电刀排龈法和压线排龈法的临床应用效果比较

    Institute of Scientific and Technical Information of China (English)

    胡晓聪; 常新

    2012-01-01

    目的 探讨电刀排龈在前牙区、前磨牙区和磨牙区的应用效果.方法 收集需冠桥修复患者47例,共90颗基牙,其中前牙、前磨牙、磨牙各30颗.根据牙位分为前牙组、前磨牙组、磨牙组,每组又分为2个亚组,分别随机选取15颗采用电刀排龈法排龈,另外15颗采用压线排龈法排龈,比较2种排龈方法的操作时间和效果.结果 前牙组、前磨牙组、磨牙组应用电刀排龈法的排龈时间分别为(2.07 ±0.10) min、(2.05±0.09)min、(2.14±0.13)min,平均排龈时间为(2.08±0.11)min;应用压线排龈法的排龈时间分别为(8.79 ±0.25) min、(8.51±0.23) min、(8.62±0.20) min,平均排龈时间为(8.64±0.25) min;2种方法的平均排龈时间差异有统计学意义(t=91.5,P<0.05).前牙组、前磨牙组、磨牙组电刀排龈法排龈效果满意率分别为100%、100%、93%,平均满意率为97%;压线排龈法排龈效果满意率分别为80%、93%、100%,平均满意率为91%;2种排龈方法的平均满意率差异无统计学意义(x2=1.90,P>0.05).结论 电刀排龈可以取得安全、满意的排龈效果,在所有牙位区的排龈操作时间均较压线排龈法明显缩短,在前牙区使用优越性较明显.%Objective To compare the effect of electrosurgical retraction in the anterior teeth, the bicuspid teeth and the posterior teeth areas, with cord gingival retraction method. Methods Forty-seven patients and a total of 90 teeth werecollected, with 30 anterior teeth, 30 bicuspid teeth and 30 posterior teeth. They were divided into anterior group; bicuspid group and posterior group. Each group were divided into two subgroups, with 15 teeth in each subgroup, for electrosurgical retractionand gingival retraclion respectively. The time and ihe effect gingival retraction were observed. Results The time of electrosurgical retraction in anterior group, bicuspid group, posterior group was (2.07 ±0. 10) inin, (2.05 ±0.09) min, (2. 14±0. 13

  3. Extremely large electronic anisotropy caused by electronic phase separation in Ca3(Ru0.97Ti0.03)2O7 single crystal

    Science.gov (United States)

    Peng, Jing; Wu, Xiaoshan; Mao, Zhiqiang

    2015-03-01

    Bilayered ruthenate Ca3 Ru2O7 exhibits rich electronic and magnetic properties. It orders at 56K, with FM bilayers antiferromagnetically coupled along c-axis (AFM-a). The AFM transition is closely followed by a first-order metal-insulator (MI) transition at 48K where spin directions switch to the b-axis (AFM-b). While this MI transition is accompanied by the opening of anisotropic charge gap; small Fermi pockets survive from the MI transition, thus resulting in quasi-2D metallic transport behavior for Tinsulating state with a nearest-neighbor AFM order via Ti doping. Ca3(Ru0 . 97 Ti0 . 03) 2O7 is close to the critical composition for the AFM-b-to-G-AFM phase transition. Our recent studies show the sample with this composition is characterized by an electronic phase separation between the insulating G-AFM phase (major) and the localized AFM-b phase (minor). The minor AFM-b phase forms a conducting path through electronic percolation within the ab-plane, but not along the c-axis, thus resulting in extremely large electronic anisotropy with ρab /ρc ~109 , which may be the largest among bulk materials.

  4. Negative chemical pressure effects induced by Y substitution for Ca on the `exotic' magnetic behavior of the spin-chain compound, Ca3Co2O6

    Indian Academy of Sciences (India)

    S Rayaprol; E V Sampathkumaran

    2005-09-01

    The magnetic behavior of a solid solution, Ca3-YCo2O6, based on the `exotic' spin-chain compound, Ca3Co2O6, crystallizing in K4CdCl6-derived rhombohedral structure is investigated. Among the compositions investigated ( = 0.0, 0.3, 0.5, 0.75 and 1.0), single-phase formation persists up to = 0.75, with the elongation of the -axis. The present investigations reveal that the temperature at which the `so-called' `partially disordered antiferromagnetic structure' sets in (which occurs at 24 K for the parent compound, = 0.0) undergoes gradual reduction with the substitution of Y for Ca, attaining the value of about 2.2 K for the nominal = 1.0. The trend observed in this characteristic temperature is opposite to that reported under external pressure, thereby establishing that Y substitution exerts negative chemical pressure. Anomalous steps observed in the isothermal magnetization at very low temperatures (around 2 K) for = 0.0, which have been proposed to arise from `quantum tunneling effects' are found to vanish by a small substitution ( = 0.3) of Y for Ca. Systematics in AC and DC magnetic susceptibility behavior with Y substitution for Ca have also been probed. We believe that the present results involving the expansion of chain length without disrupting the magnetic chain may be useful to the overall understanding of the novel magnetism of the parent compound.

  5. Study of the noise in the magnetization data across the second magnetization peak and peak effect region in Ca3Rh4Sn13

    International Nuclear Information System (INIS)

    Highlights: • We observe second magnetization peak (SMP) and peak effect (PE) in Ca3Rh4Sn13. • First measurement of noise in magnetization data across the SMP and the PE regions. • 1/f Nature of the noise is observed deep inside the Bragg glass phase. • One low resonant frequency is observed across the SMP region. • Two sets of resonant frequencies are observed in the PE region. - Abstract: In this report we make an attempt to understand the spectral fluctuations in noise in magnetization data for a single crystal of Ca3Rh4Sn13, which exhibit both the phenomena of second magnetization peak (SMP) and peak effect (PE). We find the signatures of 1/f1.8 noise deep inside the mixed phase of this superconductor. Further across the SMP region a single resonance frequency appears in the power spectra and it persists till the superconducting to normal phase boundary. While crossing the PE anomaly another set of resonance peaks in the low frequency range emerges which is distinctly different from the one which appeared in the SMP, indicating the underlying difference in the origin and nature of the SMP and PE phenomenon

  6. Immune Monitoring Using mRNA-Transfected Dendritic Cells.

    Science.gov (United States)

    Borch, Troels Holz; Svane, Inge Marie; Met, Özcan

    2016-01-01

    Dendritic cells are known to be the most potent antigen presenting cell in the immune system and are used as cellular adjuvants in therapeutic anticancer vaccines using various tumor-associated antigens or their derivatives. One way of loading antigen into the dendritic cells is by mRNA electroporation, ensuring presentation of antigen through major histocompatibility complex I and potentially activating T cells, enabling them to kill the tumor cells. Despite extensive research in the field, only one dendritic cell-based vaccine has been approved. There is therefore a great need to elucidate and understand the immunological impact of dendritic cell vaccination in order to improve clinical benefit. In this chapter, we describe a method for performing immune monitoring using peripheral blood mononuclear cells and autologous dendritic cells transfected with tumor-associated antigen-encoding mRNA. PMID:27236804

  7. Synthesis and field emission properties of Cu dendritic nanostructures

    Science.gov (United States)

    Xu, Jianwen; Yu, Ke; Zhu, Ziqiang

    2010-03-01

    Cu dendritic nanostructures were synthesized on ITO glass substructure by electrochemical deposition. SEM images showed that these Cu dendritic nanostuctures revealed a clear and well-defined dendritic fractal structure with a pronounced trunk and highly ordered branches distributed on both sides of the trunk. The diffusion-limited aggregation (DLA) model was used to explain the fractal growth of Cu dendritic nanostructures. Field emission properties of these Cu dendritic nanostructures were measured, which have possessed good performance with the turn-on field of 7.5 V/μm (defined as the electric field required to be detected at a current density of 0.1 mA/cm 2) and the field enhancement factor β of 1094.

  8. Dendrite coherency of Al-Si-Cu alloys

    Science.gov (United States)

    Veldman, Natalia L. M.; Dahle, Arne K.; Stjohn, David H.; Arnberg, Lars

    2001-01-01

    The dendrite coherency point of Al-Si-Cu alloys was determined by thermal analysis and rheological measurement methods by performing parallel measurements at two cooling rates for aluminum alloys across a wide range of silicon and copper contents. Contrary to previous findings, the two methods yield significantly different values for the fraction solid at the dendrite coherency point. This disparity is greatest for alloys of low solute concentration. The results from this study also contradict previously reported trends in the effect of cooling rate on the dendritic coherency point. Consideration of the results shows that thermal analysis is not a valid technique for the measurement of coherency. Analysis of the results from rheological testing indicates that silicon concentration has a dominant effect on grain size and dendritic morphology, independent of cooling rate and copper content, and thus is the factor that determines the fraction solid at dendrite coherency for Al-Si-Cu alloys.

  9. Effect of different Intensity Exercises in Treadmill on Learning and Memory and The Synaptic Ultrastructure in Hippocampal CA3 Area in Rats%不同强度跑台运动对大鼠学习记忆能力及海马CA3区突触超微结构的影响

    Institute of Scientific and Technical Information of China (English)

    龚云

    2012-01-01

    Effect of the different intensity treadmill exercise on learning and memory ability and hippocampal CA3 area ultrastructure was studied in rats.40 SD rats were randomly divided into four groups(control group,low-intensity exercise group,medium-intensity exercise group and high-intensity exercise group),after 60d exercise according to their respective intensity,through the one-trial passive avoidance response,the time to step-through lateney(STL) of rats was measured in every exercise group.Then 5 rats were chosen from every group,through normal ultrathin section made method,hippocampal CA3 area was observed under JEM-1230EX transmission electron microscope and photographed.The results showed that: 24 hours of STL period after electrical shock was significantly longer(P0.05) in low-intensity exercise group rats,and the hippocampal CA3 area postsynaptic density material became significantly thicker(P0.01).The curved type of synaptic interface could be divided into positively curved,negatively curved and flat,the flat type was the main.As a result,low-intensity exercise can increase memory capacity,and make the neuron synapse occurring plastic changes in the hippocampal CA3 area.The thickness of postsynaptic density material came into being a positive correlation with the strength of memory.%探讨不同强度跑台运动对大鼠学习记忆能力及海马CA3区超微结构的影响。40只Wister大鼠随机被分为4组(对照组、低强度运动组、中强度运动组、高强度运动组,各10只),按各自强度运动60 d后,通过一次性被动回避反应实验,逐只测量其步入潜伏期的时间(STL);后每组任选5只大鼠,取右侧海马CA3区按常规方法制作超薄切片,60K倍透射电镜观察并拍照,Motic Images Advanced 3.1软件测量相关突触界面结构。结果表明:低强度运动组大鼠,电击后24 h步入潜伏期的时间显著延长(P〈0.05),海马CA3区突触后膜致密

  10. 运动对大鼠学习记忆功能和海马CA3区HDAC2表达的影响%The effect by exercise on function of Rat's learning and memory as well as HDAC2 expression in hippocampal CA3 region

    Institute of Scientific and Technical Information of China (English)

    刘远新

    2012-01-01

    目的:观察中等强度、递增负荷的跑台运动对大鼠学习记忆功能和海马CA3区HDAC2表达的影响.方法:将生长发育期雄性大鼠随机分为对照组和运动组,运动组大鼠进行8周中等强度、递增负荷的跑台训练.8周后用Morris水迷宫法检测两组大鼠学习记忆能力,检测完后处死两组大鼠,在大脑海马CA3区取材,用免疫组织化学法检测大鼠大脑海马CA3区HDAC2蛋白表达.结果:定位航行实验中,运动组大鼠逃避潜伏期与对照组相比明显减少(P<0.01);空间探索实验中运动组大鼠在目标象限停留时间,穿越平台次数与对照组相比明显增加,且差异显著 (P<0.01).运动组HDAC2蛋白表达与对照组比较明显下调(P<0.05).结论:中等强度运动能促使大鼠大脑海马CA3区HDAC2表达减少,说明长期适宜的体育运动能通过抑制HDAC2表达,提高学习与记忆能力.%Objective:To reveal the effect on function of rat's learning and memory as well as HDAC2 expression in hippocampal CA3 region by moderate and incremental treadmill exercise. Methods: Male rats in developing period were randomly divided into control and exercise groups. Rats in latter group underwent incremental moderate exercise on treadmill for 8 weeks. The Morris water maze was then immediately employed to verify learning and memory of rats in both groups before being executed. Materials drawn from the hippocampus CA3 region were then processed by immunohistochemistry to assess CA3 HDAC2 protein expression. Results:It is found in navigation experiment that the escape latency of rats in exercise group was significantly reduced compared with that of the control group (P <0. 01). Both the diration of target quadrant movement and the platform-crossing number of rats in exercise group increased significantly compared that of control group with difference being statistically significant (P <0. 01). Meanwhile, HDAC2 protein expression in exercise group was

  11. Mandibular molar displacement secondary to the use of forces to retract the maxilla.

    Science.gov (United States)

    Ben-Bassat, Y; Baumrind, S; Korn, E L

    1986-01-01

    Using previously described computer-aided techniques, we have been able to characterize quantitatively the displacements of the lower first molar associated with the use of several different therapeutic modalities that are conventionally employed to retract the maxilla in the treatment of Class II malocclusion. The total displacement of the molar has been partitioned into two components associated respectively with displacement of the entire mandible and with local interosseous migration (dental compensation) of the molar within the mandible. A further attempt has been made to partition treatment-associated effects from nontreatment-associated effects. While considerable variability in effect was observed within each sample on a case-by-case basis, some important normative trends did emerge. Contrary to our expectations, it was found that in each of the treatment groups, the mean local intraosseous rotational effect (Table IIB.2) was of greater magnitude than the mean effect of mandibular rotation (Table IIB.1). The character of the intraosseous rotation differed significantly (P less than 0.05) between the control group and each of the treatment groups. In the control group, a mean mesial crown tipping (that is, "proclination") was noted. In each of the treatment groups, a mean distal crown tipping ("uprighting") was noted. In both the cervical and intraoral groups, the lower molar tended to displace mesially more than in the control or high-pull groups. This mesial displacement derived from the mesial displacement of the mandible (Table IIC.3), rather than from displacement of the tooth within the bone (Table IIC.4). In both the high-pull and the intraoral groups, the lower molar erupted within the mandible significantly more than in the control and cervical groups (Table IIC.6). The statistically significant supereruption/extrusion of the upper molar in the cervical group (Table IIC.2) was not accompanied by an associated inhibition of the eruption of the lower

  12. The effects of bone marrow mesenchymal stromal cells transplantation after mannitol pretreatment on behavioral performance and synaptophysin expression in the CA3 region in hippocampus of vascular dementia rats

    Institute of Scientific and Technical Information of China (English)

    农伟东

    2013-01-01

    Objective To investigate the effects of bone marrow mesenchymal stromal cells (BMSCs) transplantation after mannitol pretreatment on behavioral performance and synaptophysin expression in the CA3region in hippocampus of vascular dementia (VD) rats.Methods The

  13. Analyzing dendritic growth in a population of immature neurons in the adult dentate gyrus using laminar quantification of disjointed dendrites

    Directory of Open Access Journals (Sweden)

    ShiraRosenzweig

    2011-03-01

    Full Text Available In the dentate gyrus of the hippocampus, new granule neurons are continuously produced throughout adult life. A prerequisite for the successful synaptic integration of these neurons is the sprouting and extension of dendrites into the molecular layer of the dentate gyrus. Thus, studies aimed at investigating the developmental stages of adult neurogenesis often use dendritic growth as an important indicator of neuronal health and maturity. Based on the known topography of the dentate gyrus, characterized by distinct laminar arrangement of granule neurons and their extensions, we have developed a new method for analysis of dendritic growth in immature adult-born granule neurons. The method is comprised of laminar quantification of cell bodies, primary, secondary and tertiary dendrites separately and independently from each other. In contrast to most existing methods, laminar quantification of dendrites does not require the use of exogenous markers and does not involve arbitrary selection of individual neurons. The new method relies on immonuhistochemical detection of endogenous markers such as doublecortin to perform a comprehensive analysis of a sub-population of immature neurons. Disjointed, “orphan” dendrites that often appear in the thin histological sections are taken into account. Using several experimental groups of rats and mice, we demonstrate here the suitable techniques for quantifying neurons and dendrites, and explain how the ratios between the quantified values can be used in a comparative analysis to indicate variations in dendritic growth and complexity.

  14. Sphingosine 1-phosphate-induced motility and endocytosis of dendritic cells is regulated by SWAP-70 through RhoA.

    Science.gov (United States)

    Ocaña-Morgner, Carlos; Reichardt, Peter; Chopin, Michaël; Braungart, Sarah; Wahren, Christine; Gunzer, Matthias; Jessberger, Rolf

    2011-05-01

    The phospholipid mediator sphingosine 1-phosphate (S1P) enhances motility and endocytosis of mature dendritic cells (DCs). We show that in vitro migration of Swap-70(-/-) bone marrow-derived DCs (BMDCs) in response to S1P and S1P-induced upregulation of endocytosis are significantly reduced. S1P-stimulated movement of Swap-70(-/-) BMDCs, specifically retraction of their trailing edge, in a collagen three-dimensional environment is impaired. These in vitro observations correlate with delayed entry into lymphatic vessels and migration to lymph nodes of skin DCs in Swap-70(-/-) mice. Expression of S1P receptors (S1P(1-3)) by wild-type and Swap-70(-/-) BMDCs is similar, but Swap-70(-/-) BMDCs fail to activate RhoA and to localize Rac1 and RhoA into areas of actin polymerization after S1P stimulus. The Rho-activating G protein Gα(i) interacts with SWAP-70, which also supports the localization of Gα(13) to membrane rafts in BMDCs. LPS-matured Swap-70(-/-) BMDCs contain significantly more active RhoA than wild-type DCs. Preinhibition of Rho activation restored migration to S1P, S1P-induced upregulation of endocytosis in mature Swap-70(-/-) BMDCs, and localization of Gα(13) to membrane rafts. These data demonstrate SWAP-70 as a novel regulator of S1P signaling necessary for DC motility and endocytosis. PMID:21421853

  15. Dendritic Cells in vivo and in vitro

    Institute of Scientific and Technical Information of China (English)

    HuiWan; MarcelDupasquier

    2005-01-01

    Dendritic cells (DC) are crucial cells of the immune system, and bridged the essential connection between innate and adaptive immunity. They reside in the periphery as sentinels where they take up antigens. Upon activation, they migrate to lymphoid organs and present there the processed antigens to T cells, thereby activating them and eliciting a potent immune response. Dendritic cells are bone marrow-derived cells, still big controversies exist about their in vivo development. In vitro, DC can be generated from multiple precursor cells, among them lymphoid and myeloid committed progenitors. Although it remains unknown how DC are generated in vivo, studying the functions of in vitro generated DC results in fundamental knowledge of the DC biology with promising applications for future medicine. Therefore, in this review, we present current protocols for the generation of DC from precursors in vitro. We will do this for the mouse system, where most research occurs and for the human system, where research concentrates on implementing DC biology in disease treatments. Cellular & Molecular Immunology. 2005;2(1):28-35.

  16. Dendritic Cells in vivo and in vitro

    Institute of Scientific and Technical Information of China (English)

    Hui Wan; Marcel Dupasquier

    2005-01-01

    Dendritic cells (DC) are crucial cells of the immune system, and bridged the essential connection between innate and adaptive immunity. They reside in the periphery as sentinels where they take up antigens. Upon activation,they migrate to lymphoid organs and present there the processed antigens to T cells, thereby activating them and eliciting a potent immune response. Dendritic cells are bone marrow-derived cells, still big controversies exist about their in vivo development. In vitro, DC can be generated from multiple precursor cells, among them lymphoid and myeloid committed progenitors. Although it remains unknown how DC are generated in vivo,studying the functions of in vitro generated DC results in fundamental knowledge of the DC biology with promising applications for future medicine. Therefore, in this review, we present current protocols for the generation of DC from precursors in vitro. We will do this for the mouse system, where most research occurs and for the human system, where research concentrates on implementing DC biology in disease treatments.

  17. Performance Simulation of Retraction/Extension Mechanism of a Certain Aircraft%某型飞机起落架收放机构性能仿真

    Institute of Scientific and Technical Information of China (English)

    吉国明; 董萌; 付珍娟

    2012-01-01

    To test the performance of the retraction/extension mechanism of a landing gear of a certain aircraft, the mathematic model of the retraction/extension mechanism is presented, and its performance simulation is based on the 3D model of the landing gear and the ID model of the deploying-and-retracting cylinder and the fall-accelerating cylinder. The result shows that this retraction/extension mechanism with theoretical values can fulfill its deploying-and-retracting task during a limited time and that the collision among components of the landing gear is inexistent. Besides, with the help of the co-simulation model, the influence of the structural parameters of the deploying-and-retracting cylinder and fall-accelerating cylinder on the retraction/extension performance is studied, and it is suggested that the cross-section areas of the piston chamber of the deploying-and-retracting cylinder and the piston-rod chamber of the fall-accelerating cylinder are prior selection during the retraction/extension mechanism optimization progress can be as reference of the optimization design.%为了验证某型飞机起落架收放机构采用理论计算值的收放性能,建立了该型飞机起落架收放机构的数学模型,采用起落架三维模型和收放作动筒、下落加速器的一维模型进行联合仿真.结果表明:采用理论计算值能够实现起落架在有限时间里的收放任务,各部件在收放运动中无干涉.此外,利用该联合仿真模型研究了收放作动筒、下落加速器结构参数对起落架收放性能的影响,指出收放作动筒活塞截面积和下落加速器活塞杆腔截面积可作为优化设计的优先选取参数,为该型飞机起落架收放机构性能的进一步优化提供参考.

  18. Retraction: Pogačnik M, Žnidarčič D, Strgar J. A school garden in biotechnical education. Arch biol sci. 2014; 66(2:785-92, DOI: 10.2298/ABS1402785P

    Directory of Open Access Journals (Sweden)

    Editorial

    2015-01-01

    Full Text Available This is a notice of retraction of the article: A school garden in biotechnical education, published in the Archives of Biological Sciences in 2014, Vol. 66, Issue 2. Due to a printing error, caused by the journal, the same paper has already been published in the Archives of Biological Sciences, Vol. 66, Issue 1, 2014 (DOI: 10.2298/ABS1401393P. Therefore, the latter article is being retracted. The corresponding author has been informed of this error and retraction. We apologize to the authors and to the readers for this error. Link to the retracted article 10.2298/ABS1402785P

  19. Cutting edge: B220+CCR9- dendritic cells are not plasmacytoid dendritic cells but are precursors of conventional dendritic cells.

    Science.gov (United States)

    Segura, Elodie; Wong, June; Villadangos, José A

    2009-08-01

    Mouse lymphoid organs contain two major subsets of dendritic cells (DC) that differ in their phenotype and functions: conventional DC (cDC) and plasmacytoid DC (pDC). Recently, it has been proposed that differential expression of CCR9 could distinguish functionally distinct pDC subsets. We show that B220(+)CCR9(-) DC do not express classical pDC markers and have a developmental origin different from that of pDC. Furthermore, B220(+)CCR9(-) DC do not secrete IFN-alpha in response to CpG and, unlike pDC, can efficiently present exogenous Ags. Our results demonstrate that B220(+)CCR9(-) DC do not represent a subset of pDC. After in vivo transfer, these cells down-regulate B220 expression and convert into the two major cDC subsets, showing that they are a developmental stage of cDC differentiation. PMID:19570827

  20. Dendritic solidification morphology viewed from the perspective of constructal theory

    International Nuclear Information System (INIS)

    In this paper we focus on the application of the constructal theory in predicting the dendritic solid structure. First we analyse the marginal stability criterion from the perspective of the constructal principle. Having as a guiding principle the constructal law we have shown that among the whole range of possible dendrite tip radiuses predicted by the stability analysis the dendrite tip will choose the smallest one, that is a radius equal with the smallest perturbation wavelength leading to instabilities. We identify as well the existence of a competition between the diffusion controlled growth and the dendritic growth. Second, we develop a model for the secondary arm spacing. We identify a competition between the lateral diffusion controlled growth of a needle and the dendritic growth of lateral secondary arms. By analysing this competition we are able to characterize the sidebranching mechanism and to finally compute the secondary arm spacing. The result is in good agreement with the experimental results. Finally, the primary arm spacing is analysed from the perspective of the constructal law. The constructal law predicts that the only way the columnar tips can optimize the solidification process is to minimize the spacing between two adjacent tips, namely λ1. By quantifying the two mechanisms responsible for the selection of λ1, the dendrite division and the dendrite overgrown mechanisms, we were finally able to obtain a model for the primary arm spacing. This model is also validated against various experimental data

  1. NMDA spike/plateau potentials in dendrites of thalamocortical neurons.

    Science.gov (United States)

    Augustinaite, Sigita; Kuhn, Bernd; Helm, Paul Johannes; Heggelund, Paul

    2014-08-13

    Dendritic NMDA spike/plateau potentials, first discovered in cortical pyramidal neurons, provide supralinear integration of synaptic inputs on thin and distal dendrites, thereby increasing the impact of these inputs on the soma. The more specific functional role of these potentials has been difficult to clarify, partly due to the complex circuitry of cortical neurons. Thalamocortical (TC) neurons in the dorsal lateral geniculate nucleus participate in simpler circuits. They receive their primary afferent input from retina and send their output to visual cortex. Cortex, in turn, regulates this output through massive feedback to distal dendrites of the TC neurons. The TC neurons can operate in two modes related to behavioral states: burst mode prevailing during sleep, when T-type calcium bursts largely disrupt the transfer of signals from retina to cortex, and tonic mode, which provides reliable transfer of retinal signals to cortex during wakefulness. We studied dendritic potentials in TC neurons with combined two-photon calcium imaging and whole-cell recording of responses to local dendritic glutamate iontophoresis in acute brain slices from mice. We found that NMDA spike/plateaus can be elicited locally at distal dendrites of TC neurons. We suggest that these dendritic potentials have important functions in the cortical regulation of thalamocortical transmission. NMDA spike/plateaus can induce shifts in the functional mode from burst to tonic by blockade of T-type calcium conductances. Moreover, in tonic mode, they can facilitate the transfer of retinal signals to cortex by depolarization of TC neurons. PMID:25122891

  2. Dendritic mitochondria reach stable positions during circuit development

    Science.gov (United States)

    Faits, Michelle C; Zhang, Chunmeng; Soto, Florentina; Kerschensteiner, Daniel

    2016-01-01

    Mitochondria move throughout neuronal dendrites and localize to sites of energy demand. The prevailing view of dendritic mitochondria as highly motile organelles whose distribution is continually adjusted by neuronal activity via Ca2+-dependent arrests is based on observations in cultured neurons exposed to artificial stimuli. Here, we analyze the movements of mitochondria in ganglion cell dendrites in the intact retina. We find that whereas during development 30% of mitochondria are motile at any time, as dendrites mature, mitochondria all but stop moving and localize stably to synapses and branch points. Neither spontaneous nor sensory-evoked activity and Ca2+ transients alter motility of dendritic mitochondria; and pathological hyperactivity in a mouse model of retinal degeneration elevates rather than reduces motility. Thus, our findings indicate that dendritic mitochondria reach stable positions during a critical developmental period of high motility, and challenge current views about the role of activity in regulating mitochondrial transport in dendrites. DOI: http://dx.doi.org/10.7554/eLife.11583.001 PMID:26742087

  3. Adolescent cocaine exposure simplifies orbitofrontal cortical dendritic arbors

    Directory of Open Access Journals (Sweden)

    Lauren M DePoy

    2014-10-01

    Full Text Available Cocaine and amphetamine remodel dendritic spines within discrete cortico-limbic brain structures including the orbitofrontal cortex (oPFC. Whether dendrite structure is similarly affected, and whether pre-existing cellular characteristics influence behavioral vulnerabilities to drugs of abuse, remain unclear. Animal models provide an ideal venue to address these issues because neurobehavioral phenotypes can be defined both before, and following, drug exposure. We exposed mice to cocaine from postnatal days 31-35, corresponding to early adolescence, using a dosing protocol that causes impairments in an instrumental reversal task in adulthood. We then imaged and reconstructed excitatory neurons in deep-layer oPFC. Prior cocaine exposure shortened and simplified arbors, particularly in the basal region. Next, we imaged and reconstructed orbital neurons in a developmental-genetic model of cocaine vulnerability – the p190rhogap+/- mouse. p190RhoGAP is an actin cytoskeleton regulatory protein that stabilizes dendrites and dendritic spines, and p190rhogap+/- mice develop rapid and robust locomotor activation in response to cocaine. Despite this, oPFC dendritic arbors were intact in drug-naïve p190rhogap+/- mice. Together, these findings provide evidence that adolescent cocaine exposure has long-term effects on dendrite structure in the oPFC, and they suggest that cocaine-induced modifications in dendrite structure may contribute to the behavioral effects of cocaine more so than pre-existing structural abnormalities in this cell population.

  4. Control of dendritic morphogenesis by Trio in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Madhuri Shivalkar

    Full Text Available Abl tyrosine kinase and its effectors among the Rho family of GTPases each act to control dendritic morphogenesis in Drosophila. It has not been established, however, which of the many GTPase regulators in the cell link these signaling molecules in the dendrite. In axons, the bifunctional guanine exchange factor, Trio, is an essential link between the Abl tyrosine kinase signaling pathway and Rho GTPases, particularly Rac, allowing these systems to act coordinately to control actin organization. In dendritic morphogenesis, however, Abl and Rac have contrary rather than reinforcing effects, raising the question of whether Trio is involved, and if so, whether it acts through Rac, Rho or both. We now find that Trio is expressed in sensory neurons of the Drosophila embryo and regulates their dendritic arborization. trio mutants display a reduction in dendritic branching and increase in average branch length, whereas over-expression of trio has the opposite effect. We further show that it is the Rac GEF domain of Trio, and not its Rho GEF domain that is primarily responsible for the dendritic function of Trio. Thus, Trio shapes the complexity of dendritic arbors and does so in a way that mimics the effects of its target, Rac.

  5. Design of tumor-specific immunotherapies using dendritic cells - effect of bromelain on dendritic cell maturation

    OpenAIRE

    Karlsen, Marie

    2009-01-01

    Immunotherapy using dendritic cells (DC) has shown promising results in clinical trials, but few relevant successes are recorded. Therefore, the choice of an appropriate DC population is critical for the outcome of this treatment. The DC used today in immunotherapy are often matured with a cytokine cocktail consisting of TNF-α, IL-1β, IL-6 and PGE2. These cells have deficits in their cytokine production, and also their migratory capacity in vivo needs improvement. After being introduced to br...

  6. Enhanced thermoelectric performance in c-axis oriented Ca3Co4O9 films by Ag addition through multiple annealing

    Science.gov (United States)

    Liu, Shengman; Zhu, Caixia; Ge, Xianghong; Wang, Tingtai; Feng, Junlan; Yang, Linfeng

    2016-06-01

    The c-axis oriented Ca3Co4O9 (CCO) films without and with 5 wt.% Ag addition were prepared by chemical solution deposition (CSD) through multiple annealing processing on single crystal LaAlO3 (001) substrates. With Ag addition, the resistivity at 300 K is decreased to 2.25 mΩṡcm, the Seebeck coefficient at 300 K is enhanced to 106 μV/K and the power factor at 300 K can reach as high as 0.5 mWṡK‑1ṡm‑2, which is the highest value among CCO films prepared by CSD. The results suggest that Ag addition is a very effective route to improve the thermoelectric properties of CCO films through multiple annealing processing.

  7. Structural and luminescence study of Ce3+ and Tb3+ doped Ca3Sc2Si3O12 garnets obtained by freeze-drying synthesis method

    Science.gov (United States)

    Velázquez, J. J.; Fernández-González, R.; Marrero-Jerez, J.; Rodríguez, V. D.; Lukowiak, A.; Chiappini, A.; Chiasera, A.; Ferrari, M.; Núñez, P.

    2015-08-01

    Ca3Sc2Si3O12 garnets doped with Ce3+ and Tb3+ ions were synthesized by a freeze-drying precursor method. The structural characterization was performed by X-ray diffraction (XRD) and Raman spectroscopy. Scanning Electron Microscopy (SEM) images of the calcined material were studied. High temperature treatments and doping with RE3+ ions resulted in a reduction of the secondary phases (Sc2O3) and an increase of the mean size of the nanocrystals, from 75 to 149 nm. These effects were confirmed by means of Raman spectra. Moreover, luminescence features of Ce3+ and Tb3+ doped samples indicated that these ions are effectively incorporated into the crystalline phase. In addition, the energy transfer processes between Ce3+ and Tb3+ ions in codoped garnets have been studied.

  8. Optical and electronic properties of one-dimensional Ca3Co2O6 thin films: Influence of the oxygen pressure

    Science.gov (United States)

    Moubah, R.; Colis, S.; Schmerber, G.; Petersen, J.; Dinia, A.

    2009-04-01

    Thin films of Ca3Co2O6 were fabricated on c-cut sapphire substrates by pulsed laser deposition. The films are polycrystalline and can be grown in a large interval of oxygen pressure with significant influence on the film texture. X-ray photoelectron spectroscopy analyses indicated that only Co3+ ions are present in our samples for both octahedral and trigonal prismatic sites. The band gap measured by ultraviolet-visible light absorption experiments was found about 1.35 eV and slightly larger when the oxygen partial pressure during the deposition is increased from 10-3 to 7×10-2 mbar. Temperature dependent transport measurements showed a semiconducting behavior of the films and the associated band gap was found similar to the one evaluated by optical measurements and reported by theoretical studies.

  9. Crystal Growth of Ca3Nb(Ga1−xAlx3Si2O14 Piezoelectric Single Crystals with Various Al Concentrations

    Directory of Open Access Journals (Sweden)

    Yuui Yokota

    2015-08-01

    Full Text Available Ca3Nb(Ga1−xAlx3Si2O14 (CNGAS single crystals with various Al concentrations were grown by a micro-pulling-down (µ-PD method and their crystal structures, chemical compositions, crystallinities were investigated. CNGAS crystals with x = 0.2, 0.4 and 0.6 indicated a single phase of langasite-type structure without any secondary phases. In contrast, the crystals with x = 0.8 and 1 included some secondary phases in addition to the langasite-type phase. Lattice parameters, a- and c-axes lengths, of the langasite-type phase systematically decreased with an increase of Al concentration. The results of chemical composition analysis revealed that the actual Al concentrations in as-grown crystals were almost consistent with the nominal compositions. In addition, there was no large segregation of each cation along the growth direction.

  10. Dissociations of the medial and lateral perforant path projections into dorsal DG, CA3, and CA1 for spatial and nonspatial (visual object) information processing.

    Science.gov (United States)

    Hunsaker, Michael R; Mooy, Graham G; Swift, Jesse S; Kesner, Raymond P

    2007-08-01

    Medial perforant path plasticity can be attenuated by 2-amino-5-phosphonovaleric acid (APV) infusions, whereas lateral perforant path plasticity can be attenuated by naloxone infusions. The present experiment was designed to evaluate the role of each entorhinal efferent pathway into the dorsal hippocampus for detection of spatial and nonspatial (visual object) changes in the overall configuration of environmental stimuli. Dorsal dentate gyrus infusions of either APV or naloxone attenuated detection of a spatial change, whereas only naloxone infusions disrupted novel object detection. Either APV or naloxone infusions into dorsal CA3 disrupted both spatial and novel object detection. APV infusions into dorsal CA1 attenuated detection of a spatial change, whereas naloxone infusions into dorsal CA1 disrupted novel object detection. These data suggest that each dorsal hippocampal subregion processes spatial and nonspatial (visual object) information from perforant path efferents in a unique manner that is consistent with the intrinsic properties of each subregion. PMID:17663599

  11. Magnetism of the spin-chain compound Ca3Co1.9Fe0.1O6: Magnetization and neutron diffraction study

    International Nuclear Information System (INIS)

    We report the results of the dc magnetization and neutron diffraction studies of the quasi-one-dimensional spin-chain compound Ca3Co1.9Fe0.1O6. Rietveld refinement of neutron powder diffraction pattern at 100 K confirmed that Fe ion was located at trigonal prism site 6a (0, 0, 1/4). The dc susceptibility obeys the Curie-Weiss law. The appearance of additional magnetic Bragg peaks in the low temperature neutron powder diffraction patterns mainly indicates an antiferromagnetic ordering. The magnetic reflections can be indexed with a propagation vector K = (0, 0, 1), referred to the space group R3-bar c (hexagonal setting), and indicate that the centering translations have been lost in the magnetic structure.

  12. Peak effect in critical current density induced by oxygen deficiency in the CuBa2Ca3Cu4O10+δ superconductor

    International Nuclear Information System (INIS)

    Essentially single-phase samples of the CuBa2Ca3Cu4O10+δ (Cu-1234:P) phase were synthesized by a high-pressure technique utilizing an internal-oxidizing-agent method. The oxygen content of the samples was determined by coulometric titration. A novel high-oxygen-pressure heat treatment technique to introduce additional oxygen to the as-synthesized Cu-1234:P sample was developed. The critical current density (Jc) measured at 77 K under magnetic fields of 1.0-4.4 T decreased with the increase of the oxygen content and the peak effect in Jc, which was observed for the as-synthesized sample, disappeared after the introduction of additional oxygen. Thus, it is likely that the oxygen-deficient regions in the as-synthesized Cu-1234:P sample would work for some kind of pinning of the vortices to cause the peak effect. (author)

  13. Fractal structures of dendrites in GaSe crystals

    Science.gov (United States)

    Kolesnikov, N. N.; Borisenko, E. B.; Borisenko, D. N.; Bozhko, S. I.

    2008-07-01

    Solidification of melts at substantial supercooling is associated with instability on the growth front. This causes growth of dendrites, which form as a branched tree in a crystal. In the layered melt-grown GaSe crystals dendrites are observed, if growth rates are rather high [N.N. Kolesnikov, E.B. Borisenko, D.N. Borisenko, V.K. Gartman, Influence of growth conditions on microstructure and properties of GaSe crystals, J. Crystal Growth 300 (2) (2007) 294-298]. Models based on solution of the thermal diffusion problem are traditionally used to describe dendrite growth. Solution of this problem requires information about several physical parameters, such as diffusion coefficient, heat conductivity coefficient and supercooling at the solid/liquid interface. The study of scale invariance of dendrites formed in a crystal provides a new approach to solution of the dynamic growth problem. The calculated fractal dimensionality of the experimentally observed dendrites in GaSe crystals is D=1.7. It coincides with dimensionality of the clusters obtained through computer simulation in terms of the model of diffusion-limited aggregation (DLA). This result provides a new approach to description of the dynamics of dendrite growth. We have shown that the dendrite growth mechanism in the layered semiconductor crystals can be described by a two-dimensional DLA model. It is shown that probabilistic simulation can be used to show the development of a dendrite in any material. In contrast to the classical theories of dendrite growth, this approach does not require information on physical parameters.

  14. Ten-year results of cartilage palisades versus fascia in eardrum reconstruction after surgery for sinus or tensa retraction cholesteatoma in children

    DEFF Research Database (Denmark)

    Cayé-Thomasen, Per; Andersen, Janne; Uzun, Cem;

    2009-01-01

    threshold, and pure tone air-bone gap). RESULTS: All but two patients in both groups attended the 10-year follow-up examination (94% attendance). The mean overall follow-up period was 119 months (115 months in the palisade and 125 months in the fascia group). Total number of retractions during follow-up and....... METHODS: A total of 64 children underwent surgery for either sinus or tensa retraction cholesteatoma during the period 1995 to 2000 (mean age 9 years, range 5-15). The eardrum was reconstructed using cartilage palisades in 32 children (32 ears) and fascia or perichondrium in 32 children (33 ears). The...... patients were followed for at least one year postoperatively and re-evaluated 4 years after surgery, and again recently at a mean of 10 years. The main outcome measures were postoperative drum retraction and perforation, cholesteatoma recurrence, and hearing acuity (pure tone average, speech reception...

  15. 镶拼工艺回缩率在针织服装上的应用%Application of Stitching Process Retraction Rate in Knitted Clothing

    Institute of Scientific and Technical Information of China (English)

    李杰

    2012-01-01

    The process retraction rate of knitted fabric was tested through different stitching process using several kinds of fabrics. The test results indicated that stitching process retraction rate was related with stitching pattern, warp & weft of fabric and fabric type, and also proposed that stitching process retraction rate should be considered in design and production of knitted garments.%采用不同缝型、经纬向缝合,测定了不同针织面料的工艺回缩率。试验结果表明针织服装异料拼接工艺回缩率与缝型、面料经纬向和面料原材料密切相关,针织服装实际设计与生产中应考虑镶拼工艺回缩率因素对成衣的影响。

  16. Early adenosine release contributes to hypoxia-induced disruption of stimulus-induced sharp wave-ripple complexes in rat hippocampal area CA3.

    Science.gov (United States)

    Jarosch, Marlene S; Gebhardt, Christine; Fano, Silvia; Huchzermeyer, Christine; Ul Haq, Rizwan; Behrens, Christoph J; Heinemann, Uwe

    2015-07-01

    We investigated the effects of hypoxia on sharp wave-ripple complex (SPW-R) activity and recurrent epileptiform discharges in rat hippocampal slices, and the mechanisms underlying block of this activity. Oxygen levels were measured using Clark-style oxygen sensor microelectrodes. In contrast to recurrent epileptiform discharges, oxygen consumption was negligible during SPW-R activity. These network activities were reversibly blocked when oxygen levels were reduced to 20% or less for 3 min. The prolongation of hypoxic periods to 6 min caused reversible block of SPW-Rs during 20% oxygen and irreversible block when 0% oxygen (anoxia) was applied. In contrast, recurrent epileptiform discharges were more resistant to prolonged anoxia and almost fully recovered after 6 min of anoxia. SPW-Rs were unaffected by the application of 1-butyl-3-(4-methylphenylsulfonyl) urea, a blocker of KATP channels, but they were blocked by activation of adenosine A1 receptors. In support of a modulatory function of adenosine, the amplitude and incidence of SPW-Rs were increased during application of the A1 receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX). Interestingly, hypoxia decreased the frequency of miniature excitatory post-synaptic currents in CA3 pyramidal cells, an effect that was converted into increased frequency by the adenosine A1 agonist DPCPX. In addition, DPCPX also delayed the onset of hypoxia-mediated block of SPW-Rs. Our data suggest that early adenosine release during hypoxia induces a decrease in pre-synaptic glutamate release and that both might contribute to transient block of SPW-Rs during hypoxia/anoxia in area CA3. PMID:25959377

  17. Information Fusion for Anomaly Detection with the Dendritic Cell Algorithm

    CERN Document Server

    Greensmith, Julie; Tedesco, Gianni

    2010-01-01

    Dendritic cells are antigen presenting cells that provide a vital link between the innate and adaptive immune system, providing the initial detection of pathogenic invaders. Research into this family of cells has revealed that they perform information fusion which directs immune responses. We have derived a Dendritic Cell Algorithm based on the functionality of these cells, by modelling the biological signals and differentiation pathways to build a control mechanism for an artificial immune system. We present algorithmic details in addition to experimental results, when the algorithm was applied to anomaly detection for the detection of port scans. The results show the Dendritic Cell Algorithm is sucessful at detecting port scans.

  18. Follicular Dendritic Cell Sarcoma of the Abdomen: the Imaging Findings

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Tae Wook; Lee, Soon Jin; Song, Hye Jong [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2010-04-15

    Follicular dendritic cell sarcoma is a rare neoplasm that originates from follicular dendritic cells in lymphoid follicles. This disease usually involves the lymph nodes, and especially the head and neck area. Rarely, extranodal sites may be affected, including tonsil, the oral cavity, liver, spleen and the gastrointestinal tract. We report here on the imaging findings of follicular dendritic cell sarcoma of the abdomen that involved the retroperitoneal lymph nodes and colon. It shows as a well-defined, enhancing homogenous mass with internal necrosis and regional lymphadenopathy.

  19. Harnessing dendritic cells in inflammatory skin diseases.

    Science.gov (United States)

    Chu, Chung-Ching; Di Meglio, Paola; Nestle, Frank O

    2011-02-01

    The skin immune system harbors a complex network of dendritic cells (DCs). Recent studies highlight a diverse functional specialization of skin DC subsets. In addition to generating cellular and humoral immunity against pathogens, skin DCs are involved in tolerogenic mechanisms to ensure the maintenance of immune homeostasis, as well as in pathogenesis of chronic inflammation in the skin when excessive immune responses are initiated and unrestrained. Harnessing DCs by directly targeting DC-derived molecules or selectively modulate DC subsets is a convincing strategy to tackle inflammatory skin diseases. In this review we discuss recent advances underlining the functional specialization of skin DCs and discuss the potential implication for future DC-based therapeutic strategies. PMID:21295490

  20. Isolation of Human Skin Dendritic Cell Subsets.

    Science.gov (United States)

    Gunawan, Merry; Jardine, Laura; Haniffa, Muzlifah

    2016-01-01

    Dendritic cells (DCs) are specialized leukocytes with antigen-processing and antigen-presenting functions. DCs can be divided into distinct subsets by anatomical location, phenotype and function. In human, the two most accessible tissues to study leukocytes are peripheral blood and skin. DCs are rare in human peripheral blood (Nestle et al., J Immunol 151:6535-6545, 1993). These factors led to the extensive use of skin DCs as the "prototype" migratory DCs in human studies. In this chapter, we detail the protocols to isolate DCs and resident macrophages from human skin. We also provide a multiparameter flow cytometry gating strategy to identify human skin DCs and to distinguish them from macrophages. PMID:27142012