bluuebunny/crossref_metadata_2025 huggingface dataset:
The Conservation Value of Secondary Forests for Vascular Epiphytes in Central Panama
Authors: Woods Carrie L. , DeWalt Saara J.
Published: May 2012

Secondary forests that develop following land abandonment could compensate for the losses of diversity and structure that accompany deforestation of old‐growth forests in tropical regions. Whether secondary forests can harbor similar species richness, density, and composition of old‐growth forests for vascular epiphytes remains largely unknown for secondary forests older than 50 yr. We examined community structure (species richness, density, and species composition) of vascular epiphytes in older secondary forests between 35 and 115 yr after land abandonment and nearby old‐growth forests to determine if the community structure of epiphytes in secondary forests approaches that of old‐growth forests over time. The recovery of epiphyte species richness was rapid with 55‐year‐old forests containing 65 percent of old‐growth epiphyte species richness. Secondary forest epiphyte communities were found to be statistically nested within secondary forests older in age and within old‐growth forests. Similarity of epiphyte communities to old‐growth forests increased to 75 percent, 115 yr after abandonment. This study suggests that secondary forests will likely recover old‐growth epiphyte richness and composition given enough time. Epiphyte densities did not recover quickly with 55‐year‐old forests having 14 percent and 115‐year‐old forests having only 49 percent of the density of old‐growth forest epiphytes. The low density of epiphytes in secondary forests could impact rainforest diversity and function. We conclude that in less than 115 yr, although secondary moist forests have high conservation value for some aspects of community structure, they are unlikely to compensate biologically for the loss of diversity and ecosystem function that high epiphyte densities provide.
Evaluation of the leukocyte differential on a new automated flow cytometry hematology analyzer
Authors: KIM J.‐E. , KIM B.‐R. , WOO K.‐S. , HAN J.‐Y.
Published: May 2012

Introduction:  The Hematoflow (Beckman Coulter, USA) is a new automated hematology analyzer, which provides a 16‐part white blood cell count (WBC) differential.

Methods:  We evaluated the differential WBC count performance of the Hematoflow. 101 blood samples from patients were selected for comparison analysis.

Results:  The methodological comparison of the WBC differential parameters of neutrophils, lymphocytes, monocytes and eosinophils showed good correlations among 4 different analyses. More than 1% of blast cells were counted in 30 of 101 samples. A good correlation for blast cell counts obtained by Hematoflow was found with the reference manual method (r=0.9637, P 0.0001). For blast B, Hematoflow shows good correlation with reference method results but did not identify blast T.

Conclusions:  These results demonstrate that the Hematoflow has a comparable performance with the Sysmex XE‐2100 and indicate that B cell lineage ALL can be identified by the use of the Hematoflow in an initial evaluation of acute leukemia.
Inspissated oral secretions and a review of their clinical, biological, and physiological significance
Authors: Flanagan Dennis
Published: May 2012

ABSTRACT  People with some chronic diseases may dehydrate and develop thick, viscous inspissated oronasal secretions that include cellular debris. This material can lead to ductal or airway obstructions that can prove to be life threatening. Asthma, allergy with superinfection, cystic fibrosis, intubated ventilation, burn injuries, and medication‐induced complications are discussed in this paper. Many patients with chronic debilitating conditions may also be unable to communicate, and so may be unable to verbally convey that they have a compromised airway or an obstruction. Therefore, it is essential to maintain hydration and good oral hygiene that not only addresses the teeth and prostheses, but also the oral mucosal surfaces. People who are institutionalized and bed‐ridden, in particular, need to be closely monitored to prevent adverse sequellae. A daily oral sweep with a 4 × 4 surgical sponge moistened with chlorhexidine may prevent aspiration pneumonia or a fatality due to an airway obstruction. Human oronasal secretions are involved with immunity, digestion, lubrication, and speech. Saliva is the most volumetrically important. These secretions moisturize inspired and expired air but can lose water, causing an increase in viscosity. The viscous secretions trap particles, food debris, and bacterial colonies, thereby increasing inspissations that may obstruct the airway.
Breast cancer suppressor candidate‐1 (BCSC‐1) is a melanoma tumor suppressor that down regulates MITF
Authors: Anghel Silvia I. , Correa‐Rochal Rafael , Budinska Eva , Boliganl Kayluz F. , Abraham Shahnaz , Colombetti Sara , Fontao Lionel , Mariotti Agnese , Rimoldi Donata , Ghanem Ghanem E. , Fisher David E. , Lévy Frederic , Delorenzi Mauro , Piguet Vincent
Published: May 2012

Understanding the molecular aberrations involved in the development and progression of metastatic melanoma (MM) is essential for a better diagnosis and targeted therapy. We identified breast cancer suppressor candidate‐1 (BCSC‐1) as a novel tumor suppressor in melanoma. BCSC‐1 expression is decreased in human MM, and its ectopic expression in MM–derived cell lines blocks tumor formation in vivo and melanoma cell proliferation in vitro while increasing cell migration. We demonstrate that BCSC‐1 binds to Sox10, which down regulates MITF, and results in a switch of melanoma cells from a proliferative to a migratory phenotype. In conclusion, we have identified BCSC‐1 as a tumor suppressor in melanoma and as a novel regulator of the MITF pathway.
Multiple Spectral Inputs Improve Motion Discrimination in the
Drosophila
Visual System
Authors: Wardill Trevor J. , List Olivier , Li Xiaofeng , Dongre Sidhartha , McCulloch Marie , Ting Chun-Yuan , O’Kane Cahir J. , Tang Shiming , Lee Chi-Hon , Hardie Roger C. , Juusola Mikko
Published: May 2012

Color and Movement

From humans to insects, color and motion information are thought to be channeled through separate neural pathways for efficient visual processing, but it remains unclear if and how these pathways interact in improving perception of moving colored stimuli. By using sophisticated
Drosophila
genetics, intracellular electrophysiology, two-photon imaging, and behavioral experiments,

Wardill
et al.

(p.
925
) found that early in the processing stage-color photoreceptors influence the motion pathway and that this input improves the flies' optomotor performance in a flight simulator.
Adapting to a Multicultural Future
Authors: Crisp Richard J. , Meleady Rose
Published: May 2012

Humans have an evolved propensity to think categorically about social groups. This propensity is manifest in cognitive processes that have broad implications for public and political endorsement of multicultural policy. Drawing on these principles, we postulate a cognitive-evolutionary account of human adaptation to social diversity. This account explains broad social trends marking a resistance to multiculturalism, while providing an important reorienting call for scholars and policy-makers seeking intervention-based solutions to the problem of prejudice.
Ancestral Hierarchy and Conflict
Authors: Boehm Christopher
Published: May 2012

AncestralPan, the shared predecessor of humans, bonobos, and chimpanzees, lived in social dominance hierarchies that created conflict through individual and coalitional competition. This ancestor had male and female mediators, but individuals often reconciled independently. An evolutionary trajectory is traced from this ancestor to extant hunter-gatherers, whose coalitional behavior results in suppressed dominance and competition, except in mate competition. A territorial ancestralPanwould not have engaged in intensive warfare if we consider bonobo behavior, but modern human foragers have the potential for full-scale war. Although hunter-gatherers are able to resolve conflicts preemptively, they also use mechanisms, such as truces and peace pacts, to mitigate conflict when the costs become too high. Today, humans retain the genetic underpinnings of both conflict and conflict management; thus, we retain the potential for both war and peace.
The Antiquity of Empathy
Authors: de Waal Frans B. M.
Published: May 2012

The view of humans as violent war-prone apes is poorly supported by archaeological evidence and only partly supported by the behavior of our closest primate relatives, chimpanzees and bonobos. Whereas the first species is marked by xenophobia, the second is relatively peaceful and highly empathic in both behavior and brain organization. Animal empathy is best regarded as a multilayered phenomenon, built around motor mirroring and shared neural representations at basal levels, that develops into more advanced cognitive perspective-taking in large-brained species. As indicated by both observational and experimental studies on our closest relatives, empathy may be the main motivator of prosocial behavior.
Ethnicity and Conflict: Theory and Facts
Authors: Esteban Joan , Mayoral Laura , Ray Debraj
Published: May 2012

Over the second half of the 20th century, conflicts within national boundaries became increasingly dominant. One-third of all countries experienced civil conflict. Many (if not most) such conflicts involved violence along ethnic lines. On the basis of recent theoretical and empirical research, we provide evidence that preexisting ethnic divisions do influence social conflict. Our analysis also points to particular channels of influence. Specifically, we show that two different measures of ethnic division—polarization and fractionalization—jointly influence conflict, the former more so when the winners enjoy a “public” prize (such as political power or religious hegemony), the latter more so when the prize is “private” (such as looted resources, government subsidies, or infrastructures). The available data appear to strongly support existing theories of intergroup conflict. Our argument also provides indirect evidence that ethnic conflicts are likely to be instrumental, rather than driven by primordial hatreds.
Parochialism as a Central Challenge in Counterinsurgency
Authors: Sambanis Nicholas , Schulhofer-Wohl Jonah , Shayo Moses
Published: May 2012

Current U.S. practice in Afghanistan may reify social divisions, which undermines institutions critical to postwar stability.
The Ultimate Sacrifice
Authors: Gibbons Ann
Published: May 2012

Seeking to impress both gods and humans, early state societies across the globe displayed their power by ritually killing human victims.
Drone Wars
Authors: Miller Greg
Published: May 2012

Are remotely piloted aircraft changing the nature of war?
MAP1272c Encodes an NlpC/P60 Protein, an Antigen Detected in Cattle with Johne's Disease
Authors: Bannantine John P. , Lingle Cari K. , Stabel Judith R. , Ramyar Kasra X. , Garcia Brandon L. , Raeber Alex J. , Schacher Pascal , Kapur Vivek , Geisbrecht Brian V.
Published: May 2012

The protein encoded by MAP1272c has been shown to be an antigen ofMycobacterium aviumsubsp.paratuberculosisthat contains an NlpC/P60 superfamily domain found in lipoproteins or integral membrane proteins. Proteins containing this domain have diverse enzymatic functions that include peptidases, amidases, and acetyltransferases. The NlpC protein was examined in comparison to over 100 recombinant proteins and showed the strongest antigenicity when analyzed with sera from cattle with Johne's disease. To further localize the immunogenicity of NlpC, recombinant proteins representing defined regions were expressed and evaluated with sera from cattle with Johne's disease. The region from amino acids 74 to 279 was shown to be the most immunogenic. This fragment was also evaluated against a commercially available enzyme-linked immunosorbent assay (ELISA). Two monoclonal antibodies were produced in mice immunized with the full-length protein, and each recognized a distinct epitope. These antibodies cross-reacted with proteins from other mycobacterial species and demonstrated variable sizes of the proteins expressed from these subspecies. Both antibodies were further analyzed, and their interaction with MAP1272c and MAP1204 was characterized by a solution-based, luminescent binding assay. These tools provide additional means to study a strong antigen ofM. aviumsubsp.paratuberculosis.
Performances of the Vitek MS Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry System for Rapid Identification of Bacteria in Routine Clinical Microbiology
Authors: Dubois Damien , Grare Marion , Prere Marie-Françoise , Segonds Christine , Marty Nicole , Oswald Eric
Published: May 2012

Rapid and cost-effective matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS)-based systems will replace conventional phenotypic methods for routine identification of bacteria. We report here the first evaluation of the new MALDI-TOF MS-based Vitek MS system in a large clinical microbiology laboratory. This system uses an original spectrum classifier algorithm and a specific database designed for the identification of clinically relevant species. We have tested 767 routine clinical isolates representative of 50 genera and 124 species. Vitek MS-based identifications were performed by means of a single deposit on a MALDI disposable target without any prior extraction step and compared with reference identifications obtained mainly with the VITEK2 phenotypic system; if the identifications were discordant, molecular techniques provided reference identifications. The Vitek MS system provided 96.2% correct identifications to the species level (86.7%), to the genus level (8.2%), or within a range of species belonging to different genera (1.3%). Conversely, 1.3% of isolates were misidentified and 2.5% were unidentified, partly because the species was not included in the database; a second deposit provided a successful identification for 0.8% of isolates unidentified with the first deposit. The Vitek MS system is a simple, convenient, and accurate method for routine bacterial identification with a single deposit, considering the high bacterial diversity studied and as evidenced by the low prevalence of species without correct identification. In addition to a second deposit in uncommon cases, expanding the spectral database is expected to further enhance performances.
Mapping a Neutralizing Epitope onto the Capsid of Adeno-Associated Virus Serotype 8
Authors: Gurda Brittney L. , Raupp Christina , Popa-Wagner Ruth , Naumer Matthias , Olson Norman H. , Ng Robert , McKenna Robert , Baker Timothy S. , Kleinschmidt Jürgen A. , Agbandje-McKenna Mavis
Published: May 2012

Adeno-associated viruses (AAVs) are small single-stranded DNA viruses that can package and deliver nongenomic DNA for therapeutic gene delivery. AAV8, a liver-tropic vector, has shown great promise for the treatment of hemophilia A and B. However, as with other AAV vectors, host anti-capsid immune responses are a deterrent to therapeutic success. To characterize the antigenic structure of this vector, cryo-electron microscopy and image reconstruction (cryo-reconstruction) combined with molecular genetics, biochemistry, and
in vivo
approaches were used to define an antigenic epitope on the AAV8 capsid surface for a neutralizing monoclonal antibody, ADK8. Docking of the crystal structures of AAV8 and a generic Fab into the cryo-reconstruction for the AAV8-ADK8 complex identified a footprint on the prominent protrusions that flank the 3-fold axes of the icosahedrally symmetric capsid. Mutagenesis and cell-binding studies, along with
in vitro
and
in vivo
transduction assays, showed that the major ADK8 epitope is formed by an AAV variable region, VRVIII (amino acids 586 to 591 [AAV8 VP1 numbering]), which lies on the surface of the protrusions facing the 3-fold axis. This region plays a role in AAV2 and AAV8 cellular transduction. Coincidently, cell binding and trafficking assays indicate that ADK8 affects a postentry step required for successful virus trafficking to the nucleus, suggesting a probable mechanism of neutralization. This structure-directed strategy for characterizing the antigenic regions of AAVs can thus generate useful information to help re-engineer vectors that escape host neutralization and are hence more efficacious.
Vpu Mediates Depletion of Interferon Regulatory Factor 3 during HIV Infection by a Lysosome-Dependent Mechanism
Authors: Doehle Brian P. , Chang Kristina , Rustagi Arjun , McNevin John , McElrath M. Juliana , Gale Michael
Published: May 2012

HIV has evolved sophisticated mechanisms to avoid restriction by intracellular innate immune defenses that otherwise serve to control acute viral infection and virus dissemination. Innate defenses are triggered when pattern recognition receptor (PRR) proteins of the host cell engage pathogen-associated molecule patterns (PAMPs) present in viral products. Interferon regulatory factor 3 (IRF3) plays a central role in PRR signaling of innate immunity to drive the expression of type I interferon (IFN) and interferon-stimulated genes (ISGs), including a variety of HIV restriction factors, that serve to limit viral replication directly and/or program adaptive immunity. Productive infection of T cells by HIV is dependent upon the targeted proteolysis of IRF3 that occurs through a virus-directed mechanism that results in suppression of innate immune defenses. However, the mechanisms by which HIV controls innate immune signaling and IRF3 function are not defined. Here, we examined the innate immune response induced by HIV strains identified through their differential control of PRR signaling. We identified viruses that, unlike typical circulating HIV strains, lack the ability to degrade IRF3. Our studies show that IRF3 regulation maps specifically to the HIV accessory protein Vpu. We define a molecular interaction between Vpu and IRF3 that redirects IRF3 to the endolysosome for proteolytic degradation, thus allowing HIV to avoid the innate antiviral immune response. Our studies reveal that Vpu is an important IRF3 regulator that supports acute HIV infection through innate immune suppression. These observations define the Vpu-IRF3 interface as a novel target for therapeutic strategies aimed at enhancing the immune response to HIV.
Poly(A)-Binding Protein Facilitates Translation of an Uncapped/Nonpolyadenylated Viral RNA by Binding to the 3′ Untranslated Region
Authors: Iwakawa Hiro-oki , Tajima Yuri , Taniguchi Takako , Kaido Masanori , Mise Kazuyuki , Tomari Yukihide , Taniguchi Hisaaki , Okuno Tetsuro
Published: May 2012

Viruses employ an alternative translation mechanism to exploit cellular resources at the expense of host mRNAs and to allow preferential translation. Plant RNA viruses often lack both a 5′ cap and a 3′ poly(A) tail in their genomic RNAs. Instead, cap-independent translation enhancer elements (CITEs) located in the 3′ untranslated region (UTR) mediate their translation. Although eukaryotic translation initiation factors (eIFs) or ribosomes have been shown to bind to the 3′CITEs, our knowledge is still limited for the mechanism, especially for cellular factors. Here, we searched for cellular factors that stimulate the 3′CITE-mediated translation of
Red clover necrotic mosaic virus
(RCNMV) RNA1 using RNA aptamer-based one-step affinity chromatography, followed by mass spectrometry analysis. We identified the poly(A)-binding protein (PABP) as one of the key players in the 3′CITE-mediated translation of RCNMV RNA1. We found that PABP binds to an A-rich sequence (ARS) in the viral 3′ UTR. The ARS is conserved among dianthoviruses. Mutagenesis and a tethering assay revealed that the PABP-ARS interaction stimulates 3′CITE-mediated translation of RCNMV RNA1. We also found that both the ARS and 3′CITE are important for the recruitment of the plant eIF4F and eIFiso4F factors to the 3′ UTR and of the 40S ribosomal subunit to the viral mRNA. Our results suggest that dianthoviruses have evolved the ARS and 3′CITE as substitutes for the 3′ poly(A) tail and the 5′ cap of eukaryotic mRNAs for the efficient recruitment of eIFs, PABP, and ribosomes to the uncapped/nonpolyadenylated viral mRNA.
Cryphonectria nitschkei
Virus 1 Structure Shows that the Capsid Protein of Chrysoviruses Is a Duplicated Helix-Rich Fold Conserved in Fungal Double-Stranded RNA Viruses
Authors: Gómez-Blanco Josué , Luque Daniel , González José M. , Carrascosa José L. , Alfonso Carlos , Trus Benes , Havens Wendy M. , Ghabrial Said A. , Castón José R.
Published: May 2012

Cryoelectron microscopy reconstruction of
Cryphonectria nitschkei
virus 1, a double-stranded RNA (dsRNA) virus, shows that the capsid protein (60 copies/particle) is formed by a repeated helical core, indicative of gene duplication. This unusual organization is common to chrysoviruses. The arrangement of many of these putative α-helices is conserved in the totivirus L-A capsid protein, suggesting a shared motif. Our results indicate that a 120-subunit T=1 capsid is a conserved architecture that optimizes dsRNA replication and organization.
Ethanolamine Controls Expression of Genes Encoding Components Involved in Interkingdom Signaling and Virulence in Enterohemorrhagic Escherichia coli O157:H7
Authors: Kendall Melissa M. , Gruber Charley C. , Parker Christopher T. , Sperandio Vanessa
Published: May 2012

Bacterial pathogens must be able to both recognize suitable niches within the host for colonization and successfully compete with commensal flora for nutrients in order to establish infection. Ethanolamine (EA) is a major component of mammalian and bacterial membranes and is used by pathogens as a carbon and/or nitrogen source in the gastrointestinal tract. The deadly human pathogen enterohemorrhagic
Escherichia coli
O157:H7 (EHEC) uses EA in the intestine as a nitrogen source as a competitive advantage for colonization over the microbial flora. Here we show that EA is not only important for nitrogen metabolism but that it is also used as a signaling molecule in cell-to-cell signaling to activate virulence gene expression in EHEC. EA in concentrations that cannot promote growth as a nitrogen source can activate expression of EHEC’s repertoire of virulence genes. The EutR transcription factor, known to be the receptor of EA, is only partially responsible for this regulation, suggesting that yet another EA receptor exists. This important link of EA with metabolism, cell-to-cell signaling, and pathogenesis, highlights the fact that a fundamental means of communication within microbial communities relies on energy production and processing of metabolites. Here we show for the first time that bacterial pathogens not only exploit EA as a metabolite but also coopt EA as a signaling molecule to recognize the gastrointestinal environment and promote virulence expression.

IMPORTANCE
In order to successfully cause disease, a pathogen must be able to sense a host environment and modulate expression of its virulence genes as well as compete with the indigenous microbiota for nutrients. Ethanolamine (EA) is present in the large intestine due to the turnover of intestinal cells. Here, we show that the human pathogen
Escherichia coli
O157:H7, which causes bloody diarrhea and hemolytic-uremic syndrome, regulates virulence gene expression through EA metabolism and by responding to EA as a signal. These findings provide the first information directly linking EA with bacterial pathogenesis.
NEW ANALYTICAL METHOD OF DISPERSION CURVES IN PLANE LAYERED STRUCTURES
Authors: PACHIU C. , FRANKLIN H. , IZBICKI J.-L.
Published: May 2012

The propagation of sound through plane layered structures is considered, with emphasis on three-layers made up of thick isotropic plates coupled with a thin anisotropic one. Modes are obtained by means of the transition terms method (TTM) based upon the use of the reflection and transmission coefficients. This method differs from the root searching methods (RSM) of dispersion equations such as, for instance, the Newton–Raphson method. The TTM provides dispersion curves with very little computation time. It unifies the dual representation of the dispersion curves: either complex wave numbers versus the real frequency, or complex frequencies versus the real wave number. The application to various cases of three-layer structures allows us to check the validity of the method and to discuss the connection between the TTM and Cremer's correspondence principle.
MICROWAVE-ASSISTED SYNTHESIS AND CHARACTERIZATION OF CaS NANOPARTICLES
Authors: ROY ARUP , BHATTACHARYA JAYANTA
Published: May 2012

CaS nanoparticles have been synthesized by microwave irradiation, using Ca(Ac)2 as Ca -precursor, and thioacetamide as S -source. The as-prepared sample has a uniform morphology and high purity. After heat treatment similar results were observed. Synthesized nanoparticles were characterized by X-ray powder analysis (XRD), field emission scanning microscopy (FESEM), high resolution transmission electron microscopy (TEM), and UV-Vis absorption spectroscopy. X-ray diffraction patterns suggest the formation of single cubical face of CaS having average particle size of 22 nm. HRTEM micrographs reveal well dispersed cubical morphology with a size distribution of 18–30 nm. Ultraviolet-visible (UV-Vis) spectroscopy shows absorption at 268 nm. In nutshell, microwave irradiation is proved to be a convenient, efficient and environmental-friendly one-step route to synthesize nanoparticles.
Formation and characterization of five- and six-coordinate iron(III) corrolazine complexes
Authors: Kurahashi Satoshi , Ikeue Takahisa , Sugimori Tamotsu , Takahashi Masashi , Mikuriya Masahiro , Handa Makoto , Ikezaki Akira , Nakamura Mikio
Published: May 2012

Electronic structures of five- and six-coordinate iron(III) corrolazine complexes are determined by means of1H NMR,13C NMR, EPR, and Mössbauer spectroscopy as well as SQUID magnetometry. A series of five-coordinate complexes, [FeIII(TBP8Cz)(L)]* where the axial ligands(L) are cyanide(CN-), imidazole(HIm), 1-methylimidazole(1-MeIm), 4-(N,N-dimethylamino)pyridine(DMAP), pyridine(Py), 4-cyanopyridine(4-CNPy), and tert-butylisocyanide(tBuNC), are obtained by the addition of 1 to 2 equiv. of the ligands to the dichloromethane solutions of FeIII(TBP8Cz) at 298 K: TBP8Cz is a trianion of 2,3,7,8,12,13,17,18-octakis(4-tert-butylphenyl)corrolazine. These complexes commonly show the S = 3/2 at 298 K. By contrast, formation of the six-coordinate complexes depends on the nature of the axial ligands. While the addition of 3 equiv. of CN-has completely converted FeIII(TBP8Cz) to (Bu4N)2[FeIII(TBP8Cz)(CN)2] at 298 K, the conversion to the bis-adduct is only attained below ca. 200 K in the case of HIm, 1-MeIm, and DMAP even in the presence of 50 equiv. of the ligands. If the axial ligand is Py, 4-CNPy, ortBuNC, the formation of [FeIII(TBP8Cz)(L)2] is confirmed only at an extremely low temperature (15 K). Close inspection of the1H NMR and EPR spectra has revealed that all the bis-adducts adopt the (dxy)2(dxz, dyz)3ground state. While FeIII(TBP8Cz) forms paramagnetic bis- and mono-adduct in toluene solution at 298 K in the presence of excess amount of CN-andtBuNC, respectively, the corresponding porphyrazine complex, [FeIII(TBP8Pz)]Cl , forms diamagnetic bis-CN and bis-tBuNC under the same conditions: TBP8Pz is a dianion of 2,3,7,8,12,13,17,18-octakis(4-tert-butylphenyl)-porphyrazine. Thus, the iron(III) ion of porphyrazine complex is more easily reduced than that of the corresponding corrolazine complex.
INFLATION AND COMPACT HYPERBOLIC EXTRA DIMENSIONS
Authors: KIM YOONBAI , PARK SEONG CHAN
Published: May 2012

We propose a scenario of cosmological inflation, called "hyperbolic inflation", based on compact hyperbolic extra dimensions and a non-minimal coupling term (ξϕ2 R) with a simple inflaton potential (λϕ4) in Ref. 1. The non-minimal coupling term ensures the presence of the slow-roll inflation potential and the large compact hyperbolic extra dimension provides an explanation to the seemingly unnatural smallness of the non-minimal coupling constant (λ/ξ2 ~ 10-10). The natural scale of inflation of the order of 1013 GeV is singled out fitting the current cosmological observations and predicts a sizable gravitational perturbation, r ≃ 3 × 10-3.
SCALAR, FOUR VOLUME AND HOLOGRAPHIC DARK ENERGY
Authors: GAO CHANGJUN
Published: May 2012

We explore the cosmic evolution of a scalar field which is identified with the four dimensional spacetime volume. Given a specific form for the Lagrangian of the scalar field, a new holographic dark energy model is present. The energy density of dark energy is reversely proportional to the square of the radius of the cosmic null hypersurface which is present as a new infrared cutoff for the Universe. We find this holographic dark energy belongs to the phantom dark energy for some appropriate parameters in order to interpret the current acceleration of the Universe.
TRIPLE LAYERED COMPACT STAR WITH STRANGE QUARK MATTER
Authors: KIM KYUNGMIN , LEE HYUN KYU , RHO MANNQUE
Published: May 2012

We explore the possibility of three phases in the core of neutron star in a form of triple layers. From the center, strange quark matter, kaon condensed nuclear matter and nuclear matter form a triple layer. We discuss how the phase of strange quark matter is smoothly connected to kaon condensed nuclear matter phase. We also demonstrate that the compact star with triple layered structure can be a model compatible with the 1.97-solar-mass object PSR J1614-2230 recently observed.
NEW CHANCE FOR RESEARCHES ON LORENTZ VIOLATION
Authors: MA BO-QIANG
Published: May 2012

I present a brief review on the motivation for the study on Lorentz violation and on some of our studies with phenomenological analysis of Lorentz violation effects. I also discuss three effective field theory frameworks for Lorentz violation: the Coleman-Glashow model, the standard model extension (SME), and the standard model supplement (SMS). The situation of the OPERA "anomaly" is also briefly reviewed, together with some discussion on the superluminality of neutrinos within the effective field theory frameworks.
MONTE CARLO SIMULATION OF SPIN RELAXATION IN NANOWIRES AND 2-D CHANNELS OF II–VI SEMICONDUCTORS
Authors: SHARMA ASHUTOSH , NIMJE SWETALI , SALIMATH AKSHAYKUMAR , GHOSH BAHNIMAN
Published: May 2012

We have analyzed spin relaxation behavior of various II–VI semiconductors for nanowire structure and 2-D channel by simulating spin polarized transport through a semiclassical approach. Monte Carlo simulation method has been applied to simulate our model. D'yakonov–Perel mechanism and Elliot–Yafet mechanism are dominant for spin relaxation in II–VI semiconductors. Variation in spin relaxation length with external field has been analyzed and comparison is drawn between nanowire and 2-D channels. Spin relaxation lengths of various II–VI semiconductors are compared at an external field of 1 kV/cm to understand the predominant factors affecting spin dephasing in them. Among the many results obtained, most noticeable one is that spin relaxation length in nanowires is many times greater than that in 2-D channel.
Polyamines regulate intestinal epithelial restitution through TRPC1-mediated Ca2+ signaling by differentially modulating STIM1 and STIM2
Authors: Rao Jaladanki N. , Rathor Navneeta , Zhuang Ran , Zou Tongtong , Liu Lan , Xiao Lan , Turner Douglas J. , Wang Jian-Ying
Published: May 2012

Early epithelial restitution occurs as a consequence of intestinal epithelial cell (IEC) migration after wounding, and its defective regulation is implicated in various critical pathological conditions. Polyamines stimulate intestinal epithelial restitution, but their exact mechanism remains unclear. Canonical transient receptor potential-1 (TRPC1)-mediated Ca2+ signaling is crucial for stimulation of IEC migration after wounding, and induced translocation of stromal interaction molecule 1 (STIM1) to the plasma membrane activates TRPC1-mediated Ca2+ influx and thus enhanced restitution. Here, we show that polyamines regulate intestinal epithelial restitution through TRPC1-mediated Ca2+ signaling by altering the ratio of STIM1 to STIM2. Increasing cellular polyamines by ectopic overexpression of the ornithine decarboxylase (ODC) gene stimulated STIM1 but inhibited STIM2 expression, whereas depletion of cellular polyamines by inhibiting ODC activity decreased STIM1 but increased STIM2 levels. Induced STIM1/TRPC1 association by increasing polyamines enhanced Ca2+ influx and stimulated epithelial restitution, while decreased formation of the STIM1/TRPC1 complex by polyamine depletion decreased Ca2+ influx and repressed cell migration. Induced STIM1/STIM2 heteromers by polyamine depletion or STIM2 overexpression suppressed STIM1 membrane translocation and inhibited Ca2+ influx and epithelial restitution. These results indicate that polyamines differentially modulate cellular STIM1 and STIM2 levels in IECs, in turn controlling TRPC1-mediated Ca2+ signaling and influencing cell migration after wounding.
SK but not IK channels regulate human detrusor smooth muscle spontaneous and nerve-evoked contractions
Authors: Afeli Serge A. Y. , Rovner Eric S. , Petkov Georgi V.
Published: May 2012

Animal studies suggest that the small (SK) and intermediate (IK) conductance Ca2+-activated K+channels may contribute to detrusor smooth muscle (DSM) excitability and contractility. However, the ability of SK and IK channels to control DSM spontaneous phasic and nerve-evoked contractions in human DSM remains unclear. We first investigated SK and IK channels molecular expression in native human DSM and further assessed their functional role using isometric DSM tension recordings and SK/IK channel-selective inhibitors. Quantitative PCR experiments revealed that SK3 channel mRNA expression in isolated DSM single cells was ∼12- to 44-fold higher than SK1, SK2, and IK channels. RT-PCR studies at the single-cell level detected mRNA messages for SK3 channels but not SK1, SK2, and IK channels. Western blot and immunohistochemistry analysis further confirmed protein expression for the SK3 channel and lack of detectable protein expression for IK channel in whole DSM tissue. Apamin (1 μM), a selective SK channel inhibitor, significantly increased the spontaneous phasic contraction amplitude, muscle force integral, phasic contraction duration, and muscle tone of human DSM isolated strips. Apamin (1 μM) also increased the amplitude of human DSM electrical field stimulation (EFS)-induced contractions. However, TRAM-34 (1 μM), a selective IK channel inhibitor, had no effect on the spontaneous phasic and EFS-induced DSM contractions suggesting a lack of IK channel functional role in human DSM. In summary, our molecular and functional studies revealed that the SK, particularly the SK3 subtype, but not IK channels are expressed and regulate the spontaneous and nerve-evoked contractions in human DSM.
Intravenous renal cell transplantation for rats with acute and chronic renal failure
Authors: Kelly Katherine J. , Zhang Jizhong , Wang Mingsheng , Zhang Shaobo , Dominguez Jesus H.
Published: May 2012

Acute kidney injury (AKI) and chronic renal failure (CKD) are the most challenging problems in nephrology. Multiple therapies have been attempted but these interventions have minimal effects on the eventual outcomes, and all too often the result is end-stage renal disease (ESRD). The only effective therapy for ESRD is renal transplantation but only a small fraction of patients receive transplants. In this work we introduce a novel approach to transplantation designed to regenerate kidneys afflicted by severe AKI or CKD: intravenous renal cell transplantation (IRCT) with adult rat primary renal cells reprogrammed to express the SAA gene localized and engrafted in kidneys of rat recipients that had severe AKI or CKD. IRCT significantly resolved renal dysfunction and limited kidney damage, inflammation, and fibrosis. Severe CKD was successfully improved by IRCT using kidney cells from donor rats or by renal cell self-donation in a form of autotransplantation. We propose that IRCT with adult primary renal cells reprogrammed to express the SAA gene can be used to effectively treat AKI and CKD.
Methamphetamine produces bidirectional, concentration-dependent effects on dopamine neuron excitability and dopamine-mediated synaptic currents
Authors: Branch Sarah Y. , Beckstead Michael J.
Published: May 2012

Amphetamine-like compounds are commonly used to enhance cognition and to treat attention deficit/hyperactivity disorder, but they also function as positive reinforcers and are self-administered at doses far exceeding clinical relevance. Many of these compounds (including methamphetamine) are substrates for dopamine reuptake transporters, elevating extracellular dopamine by inhibiting uptake and promoting reverse transport. This produces an increase in extracellular dopamine that inhibits dopamine neuron firing through autoreceptor activation and consequently blunts phasic dopamine neurotransmission, an important learning signal. However, these mechanisms do not explain the beneficial behavioral effects observed at clinically useful concentrations. In the present study, we have used patch-clamp electrophysiology in slices of mouse midbrain to show that, surprisingly, low concentrations of methamphetamine actually enhance dopamine neurotransmission and increase dopamine neuron firing through a dopamine transporter-mediated excitatory conductance. Both of these effects are reversed by higher concentrations of methamphetamine, which inhibit firing through dopamine D2 autoreceptor activation and decrease the peak amplitude of dopamine-mediated synaptic currents. These competing, concentration-dependent effects of methamphetamine suggest a mechanistic interplay by which lower concentrations of methamphetamine can overcome autoreceptor-mediated inhibition at the soma to increase phasic dopamine transmission.
Intraglomerular inhibition shapes the strength and temporal structure of glomerular output
Authors: Shao Zuoyi , Puche Adam C. , Liu Shaolin , Shipley Michael T.
Published: May 2012

Odor signals are transmitted to the olfactory bulb by olfactory nerve (ON) synapses onto mitral/tufted cells (MCs) and external tufted cells (ETCs). ETCs, in turn, provide feedforward excitatory input to MCs. MC and ETCs are also regulated by inhibition: intraglomerular and interglomerular inhibitory circuits act at MC and ETC apical dendrites; granule cells (GCs) inhibit MC lateral dendrites via the MC→GC→MC circuit. We investigated the contribution of intraglomerular inhibition to MC and ETCs responses to ON input. ON input evokes initial excitation followed by early, strongly summating inhibitory postsynaptic currents (IPSCs) in MCs; this is followed by prolonged, intermittent IPSCs. The N-methyl-d-aspartate receptor antagonist dl-amino-5-phosphovaleric acid, known to suppress GABA release by GCs, reduced late IPSCs but had no effect on early IPSCs. In contrast, selective intraglomerular block of GABAAreceptors eliminated all early IPSCs and caused a 5-fold increase in ON-evoked MC spiking and a 10-fold increase in response duration. ETCs also receive intraglomerular inhibition; blockade of inhibition doubled ETC spike responses. By reducing ETC excitatory drive and directly inhibiting MCs, intraglomerular inhibition is a key factor shaping the strength and temporal structure of MC responses to sensory input. Sensory input generates an intraglomerular excitation-inhibition sequence that limits MC spike output to a brief temporal window. Glomerular circuits may dynamically regulate this input-output window to optimize MC encoding across sniff-sampled inputs.
Validation of a within-trial measure of the oculomotor stop process
Authors: Goonetilleke Samanthi C. , Wong Jeffrey P. , Corneil Brian D.
Published: May 2012

The countermanding (or stop signal) task requires subjects try to withhold a planned movement upon the infrequent presentation of a stop signal. We have previously proposed a within-trial measure of movement cancellation based on neck muscle recruitment during the cancellation of eye-head gaze shifts. Here, we examined such activity after either a bright or dim stop signal, a manipulation known to prolong the stop signal reaction time (SSRT). Regardless of stop signal intensity, subjects generated an appreciable number of head-only errors during successfully cancelled gaze shifts (compensatory eye-in-head motion ensured gaze stability), wherein subtle head motion toward a peripheral target was ultimately stopped by a braking pulse of antagonist neck muscle activity. Both the SSRT and timing of antagonist muscle recruitment relative to the stop signal increased for dim stop signals and decreased for longer stop signal delays. Moreover, we observed substantial variation in the distribution of antagonist muscle recruitment latencies across our sample. The magnitude and variance of the SSRTs and antagonist muscle recruitment latencies correlated positively across subjects, as did the within-subject changes across bright and dim stop signals. Finally, we fitted our behavioral data with a race model architecture that incorporated a lower threshold for initiating head movements. This model allowed us to estimate the efferent delay between the completion of a central stop process and the recruitment of antagonist neck muscles; the estimated efferent delay remained consistent within subjects across stop signal intensity. Overall, these results are consistent with the hypothesis that neck muscle recruitment during a specific subset of cancelled trials provides a peripheral expression of oculomotor cancellation on a single trial. In the discussion, we briefly speculate on the potential value of this measure for research in basic or clinical domains and consider current issues that limit more widespread use.
AMPA receptor-dependent, light-evoked d-serine release acts on retinal ganglion cell NMDA receptors
Authors: Sullivan Steve J. , Miller Robert F.
Published: May 2012

NMDA receptor (NMDAR) activation requires coincident binding of the excitatory neurotransmitter glutamate and a coagonist, either glycine or d-serine. Changes in NMDAR currents during neural transmission are typically attributed to glutamate release against a steady background of coagonist, excluding the possibility of coagonist release. AMPA receptor (AMPAR) stimulation evokes d-serine release, but it is unknown whether this is a physiological phenomenon capable of influencing synaptic responses. In this study, we utilized the intact retina to determine whether light-evoked synaptic activity in retinal ganglion cells (RGCs) is shaped by a dynamic pool of coagonist. The application of AMPAR antagonist abolished light-evoked NMDAR currents, which were rescued by adding coagonist to the bath. When NMDA was globally applied to RGCs via bath or picospritzing, the coagonist occupancy was also dependent on AMPARs but to a lesser extent than that observed during light responses, suggesting a difference in extrasynaptic coagonist regulation. By saturating the glutamate binding site of NMDARs, we were able to detect released coagonist reaching RGCs during light-evoked responses. Mutant mice lacking the d-serine-synthesizing enzyme serine racemase were deficient in coagonist release. Coagonist release in wild-type retinas was notably greater in ON than in OFF responses and depended on AMPARs. These findings suggest activity-dependent modulation of coagonist availability, particularly d-serine, and may add an extra dimension to NMDAR coincidence detection in the retina.
Level dependence of spatial processing in the primate auditory cortex
Authors: Zhou Yi , Wang Xiaoqin
Published: May 2012

Sound localization in both humans and monkeys is tolerant to changes in sound levels. The underlying neural mechanism, however, is not well understood. This study reports the level dependence of individual neurons' spatial receptive fields (SRFs) in the primary auditory cortex (A1) and the adjacent caudal field in awake marmoset monkeys. We found that most neurons' excitatory SRF components were spatially confined in response to broadband noise stimuli delivered from the upper frontal sound field. Approximately half the recorded neurons exhibited little change in spatial tuning width over a ∼20-dB change in sound level, whereas the remaining neurons showed either expansion or contraction in their tuning widths. Increased sound levels did not alter the percent distribution of tuning width for neurons collected in either cortical field. The population-averaged responses remained tuned between 30- and 80-dB sound pressure levels for neuronal groups preferring contralateral, midline, and ipsilateral locations. We further investigated the spatial extent and level dependence of the suppressive component of SRFs using a pair of sequentially presented stimuli. Forward suppression was observed when the stimuli were delivered from “far” locations, distant to the excitatory center of an SRF. In contrast to spatially confined excitation, the strength of suppression typically increased with stimulus level at both the excitatory center and far regions of an SRF. These findings indicate that although the spatial tuning of individual neurons varied with stimulus levels, their ensemble responses were level tolerant. Widespread spatial suppression may play an important role in limiting the sizes of SRFs at high sound levels in the auditory cortex.
A Comparison between Position-Based and Image-Based Dynamic Visual Servoings in the Control of a Translating Parallel Manipulator
Authors: Palmieri G. , Palpacelli M. , Battistelli M. , Callegari M.
Published: May 2012

Two different visual servoing controls have been developed to govern a translating parallel manipulator with an eye-in-hand configuration, That is, a position-based and an image-based controller. The robot must be able to reach and grasp a target randomly positioned in the workspace; the control must be adaptive to compensate motions of the target in the 3D space. The trajectory planning strategy ensures the continuity of the velocity vector for both PBVS and IBVS controls, whereas a replanning event is needed. A comparison between the two approaches is given in terms of accuracy, fastness, and stability in relation to the robot peculiar characteristics.
Modified Quasi-Steady Fuel Droplet Combustion Model
Authors: Udoetok Etim S.
Published: May 2012

The quasi-steady model of the combustion of a fuel droplet has been modified. The approach involved the modification of the quasi-steady model to reflect the difference in constant properties across the flame front. New methods for accurately estimating gas constants and for estimating Lewis number are presented. The proposed theoretical model provides results that correlate favorably with published experimental results. The proposed theoretical model also eliminates the need for unguided adjustment of thermal constants or the complex analysis of the variation of thermal properties with temperature and can serve as a basis for analysis of other combustion conditions like droplets cloud and convective and high-pressure conditions.