bluuebunny/crossref_metadata_2025 huggingface dataset:
Comprehensive experimental fitness landscape and evolutionary network for small RNA
Authors: Jiménez José I. , Xulvi-Brunet Ramon , Campbell Gregory W. , Turk-MacLeod Rebecca , Chen Irene A.
Published: August 2013

Significance

Evolution by natural selection is driven by fitness differences, which define a “fitness landscape” in the space of all possible genetic sequences. Understanding the landscape is critical for understanding and predicting natural selection, yet very little is known about the structure of a real fitness landscape. Here we experimentally determine the complete fitness landscape of small RNA selected to interact with GTP, a building block for early life. We find that the landscape is composed of largely disconnected islands of active sequences. This scenario suggests that natural selection under these conditions would be constrained to local exploration of sequence space but that replaying the initial emergence of a functional RNA could lead to a different outcome.
Huntington disease arises from a combinatory toxicity of polyglutamine and copper binding
Authors: Xiao Guiran , Fan Qiangwang , Wang Xiaoxi , Zhou Bing
Published: August 2013

Significance

The etiology of Huntington disease (HD), a progressive neurodegenerative disorder caused by polyglutamine (polyQ) expansion in huntingtin, is not well clarified. Here using a
Drosophila
model of HD, we show that altered expression of genes involved in copper metabolism can significantly modulate the HD progression. Dietary copper intervention also modifies HD phenotypes in the fly. Copper reduction dramatically decreases the level of toxic huntingtin levels. Strikingly, substitution of two potential copper-binding residues of huntingtin completely dissociates the copper-intensifying toxicity of huntingtin. Our results therefore indicate huntingtin entails both the copper-facilitated toxicity as conferred by direct copper binding and the copper-independent polyQ toxicity and suggest that an ideal HD therapy would need to take both of these actions into consideration.
Correlating preclinical animal studies and human clinical trials of a multifunctional, polymeric nanoparticle
Authors: Eliasof Scott , Lazarus Douglas , Peters Christian G. , Case Roy I. , Cole Roderic O. , Hwang Jungyeon , Schluep Thomas , Chao Joseph , Lin James , Yen Yun , Han Han , Wiley Devin T. , Zuckerman Jonathan E. , Davis Mark E.
Published: August 2013

Nanoparticles are currently being investigated in a number of human clinical trials. As information on how nanoparticles function in humans is difficult to obtain, animal studies that can be correlative to human behavior are needed to provide guidance for human clinical trials. Here, we report correlative studies on animals and humans for CRLX101, a 20- to 30-nm-diameter, multifunctional, polymeric nanoparticle containing camptothecin (CPT). CRLX101 is currently in phase 2 clinical trials, and human data from several of the clinical investigations are compared with results from multispecies animal studies. The pharmacokinetics of polymer-conjugated CPT (indicative of the CRLX101 nanoparticles) in mice, rats, dogs, and humans reveal that the area under the curve scales linearly with milligrams of CPT per square meter for all species. Plasma concentrations of unconjugated CPT released from CRLX101 in animals and humans are consistent with each other after accounting for differences in serum albumin binding of CPT. Urinary excretion of polymer-conjugated CPT occurs primarily within the initial 24 h after dosing in animals and humans. The urinary excretion dynamics of polymer-conjugated and unconjugated CPT appear similar between animals and humans. CRLX101 accumulates into solid tumors and releases CPT over a period of several days to give inhibition of its target in animal xenograft models of cancer and in the tumors of humans. Taken in total, the evidence provided from animal models on the CRLX101 mechanism of action suggests that the behavior of CRLX101 in animals is translatable to humans.
Polo-like kinase 2 regulates selective autophagic α-synuclein clearance and suppresses its toxicity in vivo
Authors: Oueslati Abid , Schneider Bernard L. , Aebischer Patrick , Lashuel Hilal A.
Published: August 2013

Significance

Converging lines of evidence suggest that increase in α-syn levels plays a central role in synucleinopathies pathogenesis. Therefore, lowering α-syn levels represents a viable therapeutic strategy for these disorders. Here, we describe a previously uncharacterized cellular mechanism controlling the selective autophagic degradation of α-syn. This effect is governed by PLK2 kinase activity, phosphorylation of α-syn, and PLK2/α-syn complex formation. In a rat model of Parkinson disease, PLK2 overexpression reduces α-syn levels and suppresses α-syn–induced toxicity and motor deficits. Collectively, our data support the neuroprotective role of PLK2 and suggest that modulating its activity is a viable therapeutic strategy for the treatment of Parkinson disease and related synucleinopathies.
In vivo imaging of alphaherpesvirus infection reveals synchronized activity dependent on axonal sorting of viral proteins
Authors: Granstedt Andrea E. , Bosse Jens B. , Thiberge Stephan Y. , Enquist Lynn W.
Published: August 2013

Significance

Pseudorabies virus (PRV), an alphaherpesvirus related to human herpes simplex and varicella-zoster viruses, causes the characteristic “mad itch” in which infected animals scratch an afflicted area until self-mutilation. The mechanism by which PRV induces these symptoms is still poorly understood, and most work has been done in limited systems in vitro. Here we report studies performed in living mice. We observed that infection with a virulent PRV strain induces synchronous and cyclical neural activity, but this activity disappears during infection with a vaccine strain that does not cause mad itch. We demonstrate the aberrant activity depends on a viral fusion protein, and its trafficking specifically into axons. These findings correlate the disrupted physiology to the known neuropathy in vivo.
H3R42me2a is a histone modification with positive transcriptional effects
Authors: Casadio Fabio , Lu Xiangdong , Pollock Samuel B. , LeRoy Gary , Garcia Benjamin A. , Muir Tom W. , Roeder Robert G. , Allis C. David
Published: August 2013

Histone posttranslational modification leads to downstream effects indirectly by allowing or preventing docking of effector molecules, or directly by changing the intrinsic biophysical properties of local chromatin. To date, little has been done to study posttranslational modifications that lie outside of the unstructured tail domains of histones. Core residues, and in particular arginines in H3 and H4, mediate key interactions between the histone octamer and DNA in forming the nucleosomal particle. Using mass spectrometry, we find that one of these core residues, arginine 42 of histone H3 (H3R42), is dimethylated in mammalian cells by the methyltransferases coactivator arginine methyltransferase 1 (CARM1) and protein arginine methyltransferase 6 (PRMT6) in vitro and in vivo, and we demonstrate that methylation of H3R42 stimulates transcription in vitro from chromatinized templates. Thus, H3R42 is a new, “nontail” histone methylation site with positive effects on transcription. We propose that methylation of basic histone residues at the DNA interface may disrupt histone:DNA interactions, with effects on downstream processes, notably transcription.
An interclausal agreement approach to switch-reference in Quechua
Authors: Assmann Anke
Published: August 2013

In this paper, I propose that switch-reference in Quechua can best be analyzed as agreeing tense. Given the properties of the Quechuan switch-reference system and the clause structure of Quechua, I assume that a switch-reference adverbial clause does not have a valued tense feature and must agree with its superordinate clause in tense. Tense agreement is only possible if the subjects of both clauses are identical. The same subject marker is analyzed as the realization of successful tense agreement, while the different subject marker is the realization of failed agreement. I argue that this approach to switch-reference is conceptually as well as empirically compelling and raises the interesting question as to whether switch-reference is a true morphosyntactic category or not. Keywords: switch-reference; Quechua; Agree; minimalist framework; non-local dependencies
Listeria monocytogenes: an intracellular pathogen of monocytes and the central nervous system.
Authors: Freitag N. E. , Bronze M. S. , Drevets D. A.
Published: August 2013

This chapter reviews literature data on the epidemiology, transmission and clinical aspects of listeriosis, as well as the molecular and cellular pathogenicity, virulence factors, and mechanisms of central nervous system invasion (through invasion of monocytes, neurons, or blood vessel endothelial cells) of Listeria monocytogenes.
Nosocomial meningitis.
Authors: Beer R. , Pfausler B.
Published: August 2013

This chapter deals with nosocomial meningitis related to invasive neurosurgical procedures, highlighting its epidemiology, common bacterial aetiology, pathogenesis (with special emphasis on biofilm formation in Staphylococcus infections), clinical aspects, diagnosis, antibacterial treatment, and prevention.
Distinct signaling mechanisms regulate migration in unconfined versus confined spaces
Authors: Hung Wei-Chien , Chen Shih-Hsun , Paul Colin D. , Stroka Kimberly M. , Lo Ying-Chun , Yang Joy T. , Konstantopoulos Konstantinos
Published: August 2013

Using a microchannel assay, we demonstrate that cells adopt distinct signaling strategies to modulate cell migration in different physical microenvironments. We studied α4β1 integrin–mediated signaling, which regulates cell migration pertinent to embryonic development, leukocyte trafficking, and melanoma invasion. We show that α4β1 integrin promotes cell migration through both unconfined and confined spaces. However, unlike unconfined (2D) migration, which depends on enhanced Rac1 activity achieved by preventing α4/paxillin binding, confined migration requires myosin II–driven contractility, which is increased when Rac1 is inhibited by α4/paxillin binding. This Rac1–myosin II cross talk mechanism also controls migration of fibroblast-like cells lacking α4β1 integrin, in which Rac1 and myosin II modulate unconfined and confined migration, respectively. We further demonstrate the distinct roles of myosin II isoforms, MIIA and MIIB, which are primarily required for confined and unconfined migration, respectively. This work provides a paradigm for the plasticity of cells migrating through different physical microenvironments.
Negative selection, not receptor editing, is a physiological response of autoreactive thymocytes
Authors: Kreslavsky Taras , Kim Hye-Jung , Koralov Sergei B. , Ghitza Dvora , Buch Thorsten , Cantor Harvey , Rajewsky Klaus , von Boehmer Harald
Published: August 2013

Antigen receptor editing—a process of secondary rearrangements of antigen receptor genes in autoreactive lymphocytes—is a well-established tolerance mechanism in B cells, whereas its role in T cells remains controversial. Here, we investigated this issue using a novel Tcra knock-in locus, which ensured appropriate timing of TCRα expression and allowed secondary rearrangements. Under these conditions the only response to self-antigen that could be unambiguously identified was negative selection of CD4/CD8 double positive thymocytes. No evidence could be obtained for antigen-induced TCR editing, whereas replacement of the transgenic TCRα chain by ongoing gene rearrangement occurred in some cells irrespective of the presence or absence of self-antigen.
Kronrod extensions with multiple nodes of quadrature formulas for Fourier coefficients
Authors: Milovanović Gradimir , Spalević Miodrag
Published: August 2013

We continue with analyzing quadrature formulas of high degree of precision for computing the Fourier coefficients in expansions of functions with respect to a system of orthogonal polynomials, started recently by Bojanov and Petrova [Quadrature formulae for Fourier coefficients, J. Comput. Appl. Math. 231 (2009), 378–391] and we extend their results. Construction of new Gaussian quadrature formulas for the Fourier coefficients of a function, based on the values of the function and its derivatives, is considered. We prove the existence and uniqueness of Kronrod extensions with multiple nodes of standard Gaussian quadrature formulas with multiple nodes for several weight functions, in order to construct some new generalizations of quadrature formulas for the Fourier coefficients. For the quadrature formulas for the Fourier coefficients based on the zeros of the corresponding orthogonal polynomials we construct Kronrod extensions with multiple nodes and highest algebraic degree of precision. For this very desirable kind of extension there do not exist any results in the theory of standard quadrature formulas.
Effect of Food Additives on Deoxynivalenol (DON) Reduction and Quality Attributes in Steamed‐and‐Fried Instant Noodles
Authors: Moazami F. E. , Jinap S. , Mousa W. , Hajeb P.
Published: August 2013

The effect of food additives reduction on quality attributes in steamed‐and‐fried instant noodles was investigated. Three additives, l‐ascorbic acid, l‐cysteine, and sodium bisulfite, were evaluated for their effect on deoxynivalenol (DON) reduction and sensory acceptability of instant noodles. After screening the different concentrations of three food additives, the maximum reduction of DON was optimized for the following concentration ranges: l‐ascorbic acid, 0–100 μg/g; l‐cysteine, 0–300 μg/g; and sodium bisulfite, 0–200 μg/g. The experimental results were fitted to a second‐order polynomial model, which gave a coefficient of determination (R2) of 0.987. The results indicated that the overall optimal condition resulting in the maximum DON reduction in instant noodles was obtained at the following combined level: sodium bisulfite, 167 μg/g; l‐cysteine, 254 μg/g; and l‐ascorbic acid, 23 μg/g. The sensory evaluation of noodles with the optimal condition of additives showed that the overall acceptability was in the range of “like slightly” and was not significantly (P > 0.05) different from the control sample. The optimized protocol produced a mixture that can reduce DON in instant noodles up to 67%. Modifying the processing of instant noodles by using additives may be useful to reduce the risk of DON exposure via instant noodles.
Iron, Oxidative Stress, and Virulence: Roles of Iron-Sensitive Transcription Factor Sre1 and the Redox Sensor ChAp1 in the Maize Pathogen Cochliobolus heterostrophus
Authors: Zhang Ning , NurAinIzzati Mohd Zainudin , Scher Keren , Condon Bradford J. , Horwitz Benjamin A. , Turgeon B. Gillian
Published: August 2013

The gene SRE1, encoding the GATA transcription factor siderophore biosynthesis repressor (Sre1), was identified in the genome of the maize pathogen Cochliobolus heterostrophus and deleted. Mutants were altered in sensitivity to iron, oxidative stress, and virulence to the host. To gain insight into mechanisms of this combined regulation, genetic interactions among SRE1 (the nonribosomal peptide synthetase encoding gene NPS6, which is responsible for extracellular siderophore biosynthesis) and ChAP1 (encoding a transcription factor regulating redox homeostasis) were studied. To identify members of the Sre1 regulon, expression of candidate iron and oxidative stress-related genes was assessed in wild-type (WT) and sre1 mutants using quantitative reverse-transcription polymerase chain reaction. In sre1 mutants, NPS6 and NPS2 genes, responsible for siderophore biosynthesis, were derepressed under iron replete conditions, whereas the high-affinity reductive iron uptake pathway associated gene, FTR1, was not, in contrast to outcomes with other well-studied fungal models. C. heterostrophus L-ornithine-N5- monooxygenase (SIDA2), ATP-binding cassette (ABC6), catalase (CAT1), and superoxide dismutase (SOD1) genes were also derepressed under iron-replete conditions in sre1 mutants. Chap1nps6 double mutants were more sensitive to oxidative stress than either Chap1 or nps6 single mutants, while Chap1sre1 double mutants showed a modest increase in resistance compared with single Chap1 mutants but were much more sensitive than sre1 mutants. These findings suggest that the NPS6 siderophore indirectly contributes to redox homeostasis via iron sequestration, while Sre1 misregulation may render cells more sensitive to oxidative stress. The double-mutant phenotypes are consistent with a model in which iron sequestration by NPS6 defends the pathogen against oxidative stress. C. heterostrophus sre1, nps6, Chap1, Chap1nps6, and Chap1sre1 mutants are all reduced in virulence toward the host, compared with the WT.
Effect ofRaspberry bushy dwarf virus, Raspberry leaf mottle virus, andRaspberry latent viruson Plant Growth and Fruit Crumbliness in ‘Meeker’ Red Raspberry
Authors: Quito-Avila Diego F. , Lightle Danielle , Martin Robert R.
Published: August 2013

Raspberry crumbly fruit in red raspberry (Rubus idaeus), widespread in the Pacific Northwest of the United States and British Columbia, Canada, is most commonly caused by a virus infection. Raspberry bushy dwarf virus (RBDV) has long been attributed as the causal agent of the disease. Recently, the identification of two additional viruses, Raspberry leaf mottle virus (RLMV) and Raspberry latent virus (RpLV), in northern Washington and British Columbia, suggested the existence of a possible new virus complex responsible for the increased severity of the disease. Virus testing of crumbly fruited plants from five fields in northern Washington revealed the presence of RLMV and RpLV, in addition to RBDV. Plants with less severe crumbly fruit symptoms had a much lower incidence of RLMV or RpLV. Field trials using replicated plots of ‘Meeker’ plants containing single and mixed infections of RBDV, RLMV, or RpLV, along with a virus-free control, were developed to determine the role of RLMV and RpLV in crumbly fruit. Field evaluations during establishment and two fruiting years revealed that plants infected with the three viruses or the combinations RBDV+RLMV and RBDV+RpLV had the greatest reduction in cane growth, or fruit firmness and fruit weight, respectively. Quantitative reverse transcription–polymerase chain reaction (RT-PCR) showed that the titer of RBDV was increased ~400-fold when it occurred in mixed infections with RLMV compared to RBDV in single infections. In addition, a virus survey revealed that RLMV and RpLV are present at high incidence in northern Washington; whereas the incidence in southern Washington and Oregon, where crumbly fruit is not as serious a problem, was considerably lower.
Genetic Variation and Gains in Resistance of Strawberry to Colletotrichum gloeosporioides
Authors: Osorio L. F. , Pattison J. A. , Peres N. A. , Whitaker V. M.
Published: August 2013

Anthracnose crown rot is an important disease of strawberry primarily caused by Colletotrichum gloeosporioides in Florida and North Carolina. Information on the magnitude of additive and nonadditive genetic variation is required to define breeding strategies and to estimate potential genetic gains. However, little is known about the genetic control of resistance and its utility in breeding. Our objectives were to obtain estimates of heritabilities and of components of genetic variances, genotype–environment interactions, and gains for resistance, and to examine the effects of locations and transplant types on the estimates. An incomplete diallel mating design generated 42 full-sib families, which were propagated in plugs from seed (seedling tests) and as bare-root runner plants (clonal tests) of different genotypes of the same families. Both seedlings and clones were inoculated with C. gloeosporioides under field conditions in North Carolina and Florida during the 2010–11 season. Narrow-sense heritability (h2) and broad-sense heritability (H2) for both clones and seedlings were higher at the North Carolina location (h2 = 0.34 to 0.62 and H2 = 0.46 to 0.85) than at the Florida location (h2 = 0.16 to 0.22 and H2 = 0.37 to 0.46). Likewise, the seedling tests showed higher genetic control than the clonal tests at both locations. Estimates of dominance variance were approximately one-third of the additive variance at North Carolina and were even larger at Florida. Epistasis was negative at both locations and assumed zero for heritability (H2) calculations. Genotype–environment interactions were different by transplant type, suggesting rank changes across locations. ‘Pelican’ was the most resistant parent at both locations, followed by ‘NCH09-68’ at the NC location and ‘Winter Dawn’ at the Florida location. Selection and deployment of the most resistant clone within each of the five best families is estimated to produce average genetic gains of 53.0 and 73.7% at the North Carolina and Florida locations, respectively.
Unipuncture Double-Access Method in Emergent Endovascular Procedures
Authors: Hörer Tal M. , Hammo Sari , Lönn Lars , Skoog Per , Larzon Thomas
Published: August 2013

We describe a technique to gain an additional endovascular access in acute situations in which a large-bore introducer is already inserted or in situations in which multiple accesses are impaired because of other reasons. Using an existing percutaneous femoral artery access, a second guide wire is inserted into the introducer, which is later withdrawn and applied onto one of the two guide wires. A double-wire access is then achieved. This access can be used, for example, for angiography or embolization catheters. This method might be useful in situations in which a quick and unplanned extra access is needed. It is, for example, applicable in hemodynamically unstable patients in whom percutaneous access can be difficult to obtain or in aortic endovascular procedures when an unplanned access is needed to insert an additional catheter for angiography and embolization.
Obesity Should Not Deter a Surgeon from Selecting a Minimally Invasive Approach for Mitral Valve Surgery
Authors: Reser Diana , Sündermann Simon , Grünenfelder Jürg , Scherman Jacques , Seifert Burkhardt , Falk Volkmar , Jacobs Stephan
Published: August 2013

Objective

Obesity is highly prevalent in modern patient populations. Several studies have published conflicting outcomes after minimally invasive surgery with regard to morbidity and mortality. Some instances consider obesity as a relative contraindication for this approach because of inadequate exposure of the surgical field. Our aim was to investigate the outcomes of minimally invasive mitral valve surgery through a right lateral minithoracotomy in patients with a body mass index (BMI) of 30 kg/m2 or greater.

Methods

We conducted a retrospective database review between January 1, 2009, and December 31, 2011. Preoperative, intraoperative, postoperative, and follow-up data of 225 consecutive patients were collected.

Results

The patients were stratified according to their BMI: 108 had a normal weight with a BMI of lower than 25 kg/m2 (18–24), 90 were overweight with a BMI of 25 to 29 kg/m2, and 27 were obese with a BMI of 30 kg/m2 (30–41) or greater. Statistical analysis showed significantly longer ventilation times in the obese group, whereas all other variables were similar. Survival, major adverse cardiac and cerebrovascular event-free survival, valve competency, and freedom from reoperation were also comparable.

Conclusions

Our data suggest that obesity should not deter a surgeon from selecting a minimally invasive approach. Despite longer postoperative ventilation times, a BMI of 30 kg/m2 or greater does not influence short- and medium-term outcome. Obese patients may even benefit from this approach because it avoids the need for sternotomy and therefore reduces the risk for sternal wound infection.
Robotically Assisted Hybrid Coronary Revascularization: Does Sequence of Intervention Matter?
Authors: Srivastava Mukta C. , Vesely Mark R. , Lee Jeffrey D. , Lehr Eric J. , Wehman Brody , Bonaros Nikolaos , Schachner Thomas , Friedrich Guy J. , Zimrin David A. , Bonatti Johannes O.
Published: August 2013

Objective

Hybrid coronary revascularization (HCR) is a treatment strategy for the revascularization of multivessel coronary disease that combines the advantages of both minimally invasive surgical techniques and percutaneous coronary intervention (PCI). The optimal sequence by which revascularization should be accomplished has not been determined. We investigated clinical outcomes in a series of patients planned for HCR via robotically assisted totally endoscopic coronary artery bypass (TECAB) and standard PCI based on revascularization sequence.

Methods

A total of 238 patients planned for HCR between 2001 and 2011 were divided into three groups based on treatment sequence: (a) TECAB before PCI, (b) PCI before TECAB, and (c) same-session procedure. Multiple procedural and clinical end points before discharge and up to 2 years after the procedure were compared between the three groups in an intention-to-treat analysis. Demographic features were reviewed to determine baseline differences between each group.

Results

Of the 238 patients, 175 (73.5%) underwent TECAB before PCI, 38 patients (16.0%) underwent PCI before TECAB, and 25 (10.5%) underwent a simultaneous revascularization procedure. At baseline, the patients undergoing TECAB before PCI were significantly older. There was a significantly higher incidence of previous myocardial infarction in the PCI-first group (P < 0.001). There was a significant difference in intensive care unit (ICU) length of stay (LOS), with shorter ICU stays in the simultaneous revascularization group (P = 0.031) and shorter hospital LOS in the PCI before TECAB group (P = 0.021).

Conclusions

In conclusion, revascularization sequence did not dramatically impact clinical outcomes in our observational study. The patients undergoing PCI-first and same-session interventions had shorter hospital and ICU LOS compared with the patients undergoing surgery first. Our findings suggest that no revascularization approach is arbitrarily superior and that revascularization sequence should be individualized on the basis of patient presentation and anatomical considerations.
Combined Heart Transplantation and Thoracic Endovascular Aortic Repair for Heart Failure Secondary to Tricuspid Atresia Palliated with Potts Shunt
Authors: Yanagawa Bobby , Collazo Lucas , Burton Nelson , Ad Niv , Speir Alan M.
Published: August 2013

A 57-year-old-man with known tricuspid atresia previously palliated with a Potts shunt had developed progressive heart failure refractory to medical management. He underwent a combined thoracic endovascular stent graft procedure to eliminate the Potts shunt and orthotopic heart transplantation. At 3-month follow-up, right-sided heart function and pulmonary artery pressures as well as pulmonary vascular resistance had normalized, and at 7 months, the patient had returned to normal activity. The surgical management and its principles as well as postoperative follow-up are described.
Hierarchically engineered fibrous scaffolds for bone regeneration
Authors: Sachot Nadège , Castaño Oscar , Mateos-Timoneda Miguel A. , Engel Elisabeth , Planell Josep A.
Published: August 2013

Surface properties of biomaterials play a major role in the governing of cell functionalities. It is well known that mechanical, chemical and nanotopographic cues, for example, influence cell proliferation and differentiation. Here, we present a novel coating protocol to produce hierarchically engineered fibrous scaffolds with tailorable surface characteristics, which mimic bone extracellular matrix. Based on the sol–gel method and a succession of surface treatments, hollow electrospun polylactic acid fibres were coated with a silicon–calcium–phosphate bioactive organic–inorganic glass. Compared with pure polymeric fibres that showed a completely smooth surface, the coated fibres exhibited a nanostructured topography and greater roughness. They also showed improved hydrophilic properties and a Young's modulus sixfold higher than non-coated ones, while remaining fully flexible and easy to handle. Rat mesenchymal stem cells cultured on these fibres showed great cellular spreading and interactions with the material. This protocol can be transferred to other structures and glasses, allowing the fabrication of various materials with well-defined features. This novel approach represents therefore a valuable improvement in the production of artificial matrices able to direct stem cell fate through physical and chemical interactions.
Echolocation versus echo suppression in humans
Authors: Wallmeier Ludwig , Geßele Nikodemus , Wiegrebe Lutz
Published: August 2013

Several studies have shown that blind humans can gather spatial information through echolocation. However, when localizing sound sources, the precedence effect suppresses spatial information of echoes, and thereby conflicts with effective echolocation. This study investigates the interaction of echolocation and echo suppression in terms of discrimination suppression in virtual acoustic space. In the ‘Listening’ experiment, sighted subjects discriminated between positions of a single sound source, the leading or the lagging of two sources, respectively. In the ‘Echolocation’ experiment, the sources were replaced by reflectors. Here, the same subjects evaluated echoes generated in real time from self-produced vocalizations and thereby discriminated between positions of a single reflector, the leading or the lagging of two reflectors, respectively. Two key results were observed. First, sighted subjects can learn to discriminate positions of reflective surfaces echo-acoustically with accuracy comparable to sound source discrimination. Second, in the Listening experiment, the presence of the leading source affected discrimination of lagging sources much more than vice versa. In the Echolocation experiment, however, the presence of both the lead and the lag strongly affected discrimination. These data show that the classically described asymmetry in the perception of leading and lagging sounds is strongly diminished in an echolocation task. Additional control experiments showed that the effect is owing to both the direct sound of the vocalization that precedes the echoes and owing to the fact that the subjects actively vocalize in the echolocation task.
Sleep facilitates long-term face adaptation
Authors: Ditye Thomas , Javadi Amir Homayoun , Carbon Claus-Christian , Walsh Vincent
Published: August 2013

Adaptation is an automatic neural mechanism supporting the optimization of visual processing on the basis of previous experiences. While the short-term effects of adaptation on behaviour and physiology have been studied extensively, perceptual long-term changes associated with adaptation are still poorly understood. Here, we show that the integration of adaptation-dependent long-term shifts in neural function is facilitated by sleep. Perceptual shifts induced by adaptation to a distorted image of a famous person were larger in a group of participants who had slept (experiment 1) or merely napped for 90 min (experiment 2) during the interval between adaptation and test compared with controls who stayed awake. Participants' individual rapid eye movement sleep duration predicted the size of post-sleep behavioural adaptation effects. Our data suggest that sleep prevented decay of adaptation in a way that is qualitatively different from the effects of reduced visual interference known as ‘storage’. In the light of the well-established link between sleep and memory consolidation, our findings link the perceptual mechanisms of sensory adaptation—which are usually not considered to play a relevant role in mnemonic processes—with learning and memory, and at the same time reveal a new function of sleep in cognition.
Ocean acidification and rising temperatures may increase biofilm primary productivity but decrease grazer consumption
Authors: Russell Bayden D. , Connell Sean D. , Findlay Helen S. , Tait Karen , Widdicombe Stephen , Mieszkowska Nova
Published: August 2013

Climate change may cause ecosystems to become trophically restructured as a result of primary producers and consumers responding differently to increasing CO
2
and temperature. This study used an integrative approach using a controlled microcosm experiment to investigate the combined effects of CO
2
and temperature on key components of the intertidal system in the UK, biofilms and their consumers (
Littorina littorea
). In addition, to identify whether pre-exposure to experimental conditions can alter experimental outcomes we explicitly tested for differential effects on
L. littorea
pre-exposed to experimental conditions for two weeks and five months. In contrast to predictions based on metabolic theory, the combination of elevated temperature and CO
2
over a five-week period caused a decrease in the amount of primary productivity consumed by grazers, while the abundance of biofilms increased. However, long-term pre-exposure to experimental conditions (five months) altered this effect, with grazing rates in these animals being greater than in animals exposed only for two weeks. We suggest that the structure of future ecosystems may not be predictable using short-term laboratory experiments alone owing to potentially confounding effects of exposure time and effects of being held in an artificial environment over prolonged time periods. A combination of laboratory (physiology responses) and large, long-term experiments (ecosystem responses) may therefore be necessary to adequately predict the complex and interactive effects of climate change as organisms may acclimate to conditions over the longer term.
Adaptation and acclimatization to ocean acidification in marine ectotherms: anin situtransplant experiment with polychaetes at a shallow CO2vent system
Authors: Calosi Piero , Rastrick Samuel P. S. , Lombardi Chiara , de Guzman Heidi J. , Davidson Laura , Jahnke Marlene , Giangrande Adriana , Hardege Jörg D. , Schulze Anja , Spicer John I. , Gambi Maria-Cristina
Published: August 2013

Metabolic rate determines the physiological and life-history performances of ectotherms. Thus, the extent to which such rates are sensitive and plastic to environmental perturbation is central to an organism's ability to function in a changing environment. Little is known of long-term metabolic plasticity and potential for metabolic adaptation in marine ectotherms exposed to elevatedpCO2. Consequently, we carried out a series ofin situtransplant experiments using a number of tolerant and sensitive polychaete species living around a natural CO2vent system. Here, we show that a marine metazoan (i.e.Platynereis dumerilii) was able to adapt to chronic and elevated levels ofpCO2. The vent population ofP. dumeriliiwas physiologically and genetically different from nearby populations that experience lowpCO2, as well as smaller in body size. By contrast, different populations ofAmphiglena mediterraneashowed marked physiological plasticity indicating that adaptation or acclimatization are both viable strategies for the successful colonization of elevatedpCO2environments. In addition, sensitive species showed either a reduced or increased metabolism when exposed acutely to elevatedpCO2. Our findings may help explain, from a metabolic perspective, the occurrence of past mass extinction, as well as shed light on alternative pathways of resilience in species facing ongoing ocean acidification.
Effects of acidification on olfactory-mediated behaviour in freshwater and marine ecosystems: a synthesis
Authors: Leduc Antoine O. H. C. , Munday Philip L. , Brown Grant E. , Ferrari Maud C. O.
Published: August 2013

For many aquatic organisms, olfactory-mediated behaviour is essential to the maintenance of numerous fitness-enhancing activities, including foraging, reproduction and predator avoidance. Studies in both freshwater and marine ecosystems have demonstrated significant impacts of anthropogenic acidification on olfactory abilities of fish and macroinvertebrates, leading to impaired behavioural responses, with potentially far-reaching consequences to population dynamics and community structure. Whereas the ecological impacts of impaired olfactory-mediated behaviour may be similar between freshwater and marine ecosystems, the underlying mechanisms are quite distinct. In acidified freshwater, molecular change to chemical cues along with reduced olfaction sensitivity appear to be the primary causes of olfactory-mediated behavioural impairment. By contrast, experiments simulating future ocean acidification suggest that interference of high CO2with brain neurotransmitter function is the primary cause for olfactory-mediated behavioural impairment in fish. Different physico-chemical characteristics between marine and freshwater systems are probably responsible for these distinct mechanisms of impairment, which, under globally rising CO2levels, may lead to strikingly different consequences to olfaction. While fluctuations in pH may occur in both freshwater and marine ecosystems, marine habitat will remain alkaline despite future ocean acidification caused by globally rising CO2levels. In this synthesis, we argue that ecosystem-specific mechanisms affecting olfaction need to be considered for effective management and conservation practices.
Arabidopsis Phospholipase Dδ Is Involved in Basal Defense and Nonhost Resistance to Powdery Mildew Fungi
Authors: Pinosa Francesco , Buhot Nathalie , Kwaaitaal Mark , Fahlberg Per , Thordal-Christensen Hans , Ellerström Mats , Andersson Mats X.
Published: August 2013

Plants have evolved a complex array of defensive responses against pathogenic microorganisms. Recognition of microbes initiates signaling cascades that activate plant defenses. The membrane lipid phosphatidic acid, produced by phospholipase D (PLD), has been shown to take part in both abiotic and biotic stress signaling. In this study, the involvement of PLD in the interaction between Arabidopsis (Arabidopsis thaliana) and the barley powdery mildew fungus Blumeria graminis f. sp. hordei (Bgh) was investigated. This nonadapted pathogen is normally resisted by a cell wall-based defense, which stops the fungal hyphae from penetrating the epidermal cell wall. Chemical inhibition of phosphatidic acid production by PLD increased the penetration rate of Bgh spores on wild-type leaves. The analysis of transfer DNA knockout lines for all Arabidopsis PLD genes revealed that PLDδ is involved in penetration resistance against Bgh, and chemical inhibition of PLDs in plants mutated in PLDδ indicated that this isoform alone is involved in Bgh resistance. In addition, we confirmed the involvement of PLDδ in penetration resistance against another nonadapted pea powdery mildew fungus, Erysiphe pisi. A green fluorescent protein fusion of PLDδ localized to the plasma membrane at the Bgh attack site, where it surrounded the cell wall reinforcement. Furthermore, in the pldδ mutant, transcriptional up-regulation of early microbe-associated molecular pattern response genes was delayed after chitin stimulation. In conclusion, we propose that PLD is involved in defense signaling in nonhost resistance against powdery mildew fungi and put PLDδ forward as the main isoform participating in this process.
Scenario‐based approach to office occupancy analysis
Authors: Khamkanya Thadsin , Heaney George , McGreal Stanley
Published: August 2013

Purpose

The office is considered as a strategic resource that can support knowledge‐based organisations to gain competitive advantage and operational efficiency. Although the modern scholar emphasises the role of user involvement in workplace design and management, there is little evidence showing how it can be linked to occupancy cost performance. The purpose of this paper is to investigate benefits of a user‐centric workplace practice by focusing on working time and space utilisation practice of office users.

Design/methodology/approach

A scenario‐based approach was designed to analyse office occupancy cost performance. A questionnaire survey was conducted from a number of UK‐based offices to create three workspace utilisation scenarios, namely, existing, property‐centric and user‐centric. Key comparison criteria include potential areas of savings, potential total cost savings and cost saving per person.

Findings

It was found that a user‐centric approach reflects an opportunity to save annual occupancy costs in terms of total costs and cost per person where users indicated how they utilised working time and space. In return, the organisations can gain more productivity from office users who are likely to perform better when they can work in the preferred workplace practice.

Practical implications

By adopting this approach, organisations can understand the occupancy characteristics of the offices from multi perspectives, leading to better management in office premises.

Originality/value

This paper is concerned with the analysis of how to achieve higher office efficiency by focusing on office user's working time and space utilisation practice.
Do investors benefit from good corporate governance?
Authors: Shank Todd , Paul Hill Ronald , Stang John
Published: August 2013

Purpose

The purpose of this paper is to examine the continuing search for evidence that good corporate governance leads to positive organizational outcomes, and it presents a unique perspective on this issue based on firm size.

Design/methodology/approach

The study utilized a comprehensive measure of governance as well as a risk‐adjusted measure of share price in its comparisons between companies known for good governance and broader markets composed of similar‐sized firms.

Findings

The findings show evidence of better risk‐adjusted performance across all recent sub‐periods (three‐, five‐, and ten‐year) for the firms in the smallest market capitalization category. Better risk‐adjusted returns were earned for only the ten‐year period for the largest firms and the overall US market. Mid‐cap stocks were not significant in any of the three periods studied. The fact that the small cap stocks showed significance for all three sub‐periods indicates the relationship between good corporate governance practices and the financial success of a company is the strongest for smaller firms and is more likely to be experienced in longer time horizons for most firms, small and large.

Research limitations/implications

Investigations of this seminal issue have produced mixed results because the operational definitions of governance often are too narrow, the timeframes for impact are too constricted, and the comparisons are too broad. In addition, the use of a novel approach for understanding why these findings may hold true provides scholars with new avenues for thinking about and modeling the governance‐performance relationship.

Practical implications

Good governance matters and requires managers and policy makers to find the appropriate context in order to have meaningful comparisons.

Social implications

The paper supports the “doing well while doing good” paradigm for both individual and institutional investors' investment choices by showing that selecting firms that practice good corporate governance can be a long‐term value‐maximizing strategy.

Originality/value

A major nuance from other studies of the impact of a firm's corporate governance performance on its financial performance is the authors' use of four sub‐categories of companies based on market capitalization/firm size. Findings ultimately show whether investors/owners reward corporate governance via stock purchases, and if so, how this relationship may have changed over the past decade according to various markets and risk‐adjusted returns.
CEO emotional intelligence and board of directors' efficiency
Authors: Azouzi Mohamed Ali , Jarboui Anis
Published: August 2013

Purpose

This paper deals with the relationship existing between the emotional aspect and decision‐making processes. More specifically, it examines the links between emotional intelligence, decision biases and effectiveness of the governance mechanisms. The primary purposes of this paper are to: consider emotional intelligence as new research ideas that make important contributions to society; offer suggestions for improving manuscripts submitted to Consortium for Research on Emotional Intelligence in Organizations; and discuss methods for enhancing the validity of inferences made from research.

Design/methodology/approach

The paper explains that the main cause of organization's problems is CEO emotional intelligence level. The authors use three models (linear regression and logistic binary regression) to examine this relation: every model treats the relationship between emotional intelligence and one of efficiency criteria of the board. Emotional intelligence has been measured according to Schutte et al.'s Shutte Self Report Emotional Intelligence Scale (SSREI), with a high internal validity level. The four cognitive biases have been measured by means of a questionnaire comprising several items and the selected sample was composed of some180 Tunisian executives (belonging to 60 firms).

Findings

The results revealed that the presence of a high emotional intelligence rate is not always positively correlated with the executives' suggestibility with respect to behavioural biases. They have also affirmed the existence of a complementarity relationship between emotional intelligence and the directors' board. Authors need to consider that emotion which minimizes CEO emotional biases and provides director's board effectiveness.

Research limitations/implications

This article has implications for the development of CEO emotional intelligence capacity. Also, some psychological aspects of a theoretical nature could not be wholly approached in a complete empirical way.

Practical implications

The paper pushes organizations to select managers based on their levels of emotional intelligence (apply tests of emotional intelligence in place psychometric tests). Also, it increases the validity of inferences made from research in the field.

Social implications

This paper incites governments to establish training programs aimed at the development of learning of emotional intelligence. Thus, it has important implications for enhancing the well‐being of individuals, organizations and society as a whole.

Originality/value

Actually, for the sake improving the explanatory power of a legal‐financial approach of governance, the behavioural dimension has been integrated for a more thorough analysis of the directors' board role. The authors' goal consists in highlighting the role played by emotional intelligence as a skill or tool available for the manager or controller to minimize the behavioural biases (bias of loss aversion, optimism, over‐confidence and lack of cognitive flexibility), and achieves an effective control.