bluuebunny/crossref_metadata_2025 huggingface dataset:
Topical rapamycin suppresses the angiogenesis pathways induced by pulsed dye laser: Molecular mechanisms of inhibition of regeneration and revascularization of photocoagulated cutaneous blood vessels
Authors: Tan Wenbin , Jia Wangcun , Sun Victor , Mihm Martin C. , Nelson J. Stuart
Published: December 2012

Background and Objectives

Pulsed dye laser (PDL) is the most effective treatment for port wine stain (PWS) birthmarks. However, regeneration and revascularization of photocoagulated blood vessels may result in poor therapeutic outcome. We have recently shown that rapamycin (RPM), an angiogenesis inhibitor, can reduce the regeneration and revascularization of photocoagulated blood vessels. Herein, we attempt to further elucidate the molecular pathophysiology on the inhibition of the regeneration and revascularization of photocoagulated blood vessels by topical RPM in an animal model.

Materials and Methods

Two separate skin areas on each hamster were irradiated by PDL. After PDL exposure, topical RPM was applied daily to one of the randomly selected test sites. PDL, PDL + RPM and normal skin test sites were biopsied on day 3 after PDL exposure. The total ribonucleic acid (RNA) and protein were extracted from biopsied skin samples and quantified. Real‐time reverse transcription‐polymerase chain reaction (RT‐PCR) and immunoblot were subsequently performed to quantify the mRNA and protein levels of hypoxia‐inducible factor‐1alpha (HIF‐1α), vascular endothelial growth factor (VEGF) and ribosomal protein S6 kinase (S6). The phosphorylation levels of S6 and AKT were also evaluated by immunoblot.

Results

The mRNA and protein levels of HIF‐1α, VEGF, and S6 significantly increased after PDL exposure as compared to the normal hamster skin. Topical application of 1% RPM suppressed the PDL‐induced increase in mRNA and protein levels of those genes on day 3 post‐PDL exposure. The phosphorylation levels of S6 and AKT increased after PDL exposure but the increases were suppressed by the topical application of RPM.

Conclusion

The increase in expression of HIF‐1α, VEGF, and S6 after PDL‐exposure suggests that angiogenesis pathways play very active roles in the process of skin blood vessel regeneration and revascularization. Topical application of 1% RPM can suppress the angiogenesis pathways and, therefore, reduce the regeneration and revascularization of photocoagulated blood vessels. Lasers Surg. Med. 44: 796–804, 2012. © 2012 Wiley Periodicals, Inc.
Fractional laser‐assisted delivery of methyl aminolevulinate: Impact of laser channel depth and incubation time
Authors: Haak Christina S. , Farinelli William A. , Tam Joshua , Doukas Apostolos G. , Anderson R. Rox , Hædersdal Merete
Published: December 2012

Background and Objectives

Pretreatment of skin with ablative fractional lasers (AFXL) enhances the uptake of topical photosensitizers used in photodynamic therapy (PDT). Distribution of photosensitizer into skin layers may depend on depth of laser channels and incubation time. This study evaluates whether depth of intradermal laser channels and incubation time may affect AFXL‐assisted delivery of methyl aminolevulinate (MAL).

Materials and Methods

Yorkshire swine were treated with CO2 AFXL at energy levels of 37, 190, and 380 mJ/laser channel and subsequent application of MAL cream (Metvix®) for 30, 60, 120, and 180 minutes incubation time. Fluorescence photography and fluorescence microscopy quantified MAL‐induced porphyrin fluorescence (PpIX) at the skin surface and at five specific skin depths (120, 500, 1,000, 1,500, and 1,800 µm).

Results

Laser channels penetrated into superficial (∼300 µm), mid (∼1,400 µm), and deep dermis/upper subcutaneous fat layer (∼2,100 µm). Similar fluorescence intensities were induced at the skin surface and throughout skin layers independent of laser channel depth (180 minutes; P < 0.19). AFXL accelerated PpIX fluorescence from skin surface to deep dermis. After laser exposure and 60 minutes MAL incubation, surface fluorescence was significantly higher compared to intact, not laser‐exposed skin at 180 minutes (AFXL‐MAL 60 minutes vs. MAL 180 minutes, 69.16 a.u. vs. 23.49 a.u.; P < 0.01). Through all skin layers (120–1,800 µm), laser exposure and 120 minutes MAL incubation induced significantly higher fluorescence intensities in HF and dermis than non‐laser exposed sites at 180 minutes (1,800 µm, AFXL‐MAL 120 minutes vs. MAL 180 minutes, HF 14.76 a.u. vs. 6.69 a.u. and dermis 6.98 a.u. vs. 5.87 a.u.; P < 0.01).

Conclusions

AFXL pretreatment accelerates PpIX accumulation, but intradermal depth of laser channels does not affect porphyrin accumulation. Further studies are required to examine these findings in clinical trials. Lasers Surg. Med. 44: 787–795, 2012. © 2012 Wiley Periodicals, Inc.
A cohort study of therapeutic prescriptions after the end of phytotherapy drug reimbursement by French Social Security
Authors: Riou França Lionel , Vidal Chrystelle , Bourechak Nadia , Jeunne Philippe Le , Deville Geoffroy Sainte‐Claire , Massol Jacques
Published: December 2012

Purpose

The reimbursement of phytotherapy drugs for the treatment of mild anxiety and insomnia ended in March 2006 in France. The aim of this study is to investigate the short‐term impact of stopping phytotherapy reimbursement.

Methods

We monitored the prescriptions of 27 422 patients who received hypnotic and sedative phytotherapy drug treatment at least once in the 12 months preceding the end of reimbursement and made contact with their prescribing physician at least once in the following 12 months. A control cohort was recruited from patients fulfilling the same inclusion criteria in the 24 months before de‐reimbursement and their prescriptions in the following 12 months were monitored. The impact of the end of reimbursement is estimated comparing prescription switches in these cohorts.

Results

Before the end of reimbursement, 7684 (28%) patients being prescribed delisted phytotherapy drugs had the relevant drug marketing authorization approval (DMAA) indications. Co‐prescriptions of hypnotic and sedative drugs concerned 40% of patients. Of the 4646 DMAA patients exclusively prescribed phytotherapy, 640 (14%) switched to hypnotic or sedative drugs only after the end of reimbursement, 3266 (70%) stopped all treatments and 740 (16%) carried on with a non‐reimbursed phytotherapy prescription. When compared to the control cohort, patients exposed to de‐reimbursement were more likely to switch to psychotropic drugs (OR = 1.46).

Conclusions

Ending the reimbursement of common drugs on the basis of insufficient evidence regarding their effectiveness or the low level of severity of their target pathologies should be accompanied by information or advice to prescribing health care actors. Copyright © 2012 John Wiley & Sons, Ltd.
Sliding wear behaviour of oriented ultrahigh molecular weight polyethylene
Authors: Eddoumy Fatima , Addiego Frédéric , Dhieb Houcine , Célis Jean‐Pierre , Muller René , Toniazzo Valérie , Ruch David
Published: December 2012

The impact of processing‐induced chain orientation on the sliding wear behaviour of ultrahigh molecular weight polyethylene (UHMWPE) was investigated. The orientation of the molecular network of UHMWPE was done by means of uniaxial tension up to different residual strains. We found that high residual strain levels (higher than 0.45) enabled the sliding dissipated energy of UHMWPE to be decreased in dry conditions. In particular, oriented UHMWPE with a residual strain of 0.85 exhibited, at 500 000 sliding cycles in dry conditions, a decrease in volumetric wear loss by a factor of 3.3 and 19.4 compared with the reference UHMWPE tested in directions parallel and perpendicular to the chain direction, respectively. It is argued that oriented UHMWPE exhibits less adhesion during interfacial wear than the reference material, and hence orientation of UHMWPE bulk may be an alternative treatment to crosslinking for dry sliding conditions. In the case of sliding testing conducted in Ringer's solution, the benefit of the initial chain orientation was quite weak due to a lubrication effect of the solution that markedly limited the effect of chain orientation on the sliding behaviour.
A comparison of the properties of two structurally equivalent but regiochemically different mono‐alkylated polybithiophenes prepared through AABB‐type stille polycondensation
Authors: Lundin Pamela M. , Giri Gaurav , Bao Zhenan
Published: December 2012

Previous routes to polymers with mono‐alkylated bithiophenes have proceeded through polymerization of monoalkyl‐2,2′‐bithiophene monomers through oxidative or AB‐type cross‐coupling polymerizations. The resulting polymer regiochemistry affects both the location and orientation of the polymer side‐chains. In contrast, AABB‐type cross‐coupling polymerizations can control the location and in some cases the orientation of the side‐chains. To study how this control can impact polymer properties, two poly(monodecyl‐2,2′‐bithiophene) polymers have been synthesized through Stille AABB‐type polycondensations of 2,5‐bis(trimethylstannyl)thiophene with different monomers. The alkyl side‐chains are located on every other thiophene, but polymer 1 consists of both head‐to‐tail and head‐to‐head dyads, whereas polymer 2 is made up of only head‐to‐head dyads. 1H NMR, 13C NMR, and heteronuclear single quantum correlation spectroscopy are used to confirm and contrast the polymer regiochemistries. The physical properties of the two polymers are analyzed using UV–vis spectroscopy, differential scanning calorimetry, and grazing‐incidence X‐ray diffraction. Polymer 2 is found to display significantly more aggregation in solution than 1, and it displays different thermal properties. The film properties of polymers 1 and 2, however, are very similar, with nearly identical UV–vis profiles and d‐spacing values as determined by grazing incidence X‐ray diffraction. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013
Synthesis of block and graft copolymers of styrene by raft polymerization, using dodecyl‐based trithiocarbonates as initiators and chain transfer agents
Authors: Ponnusamy Kannukaran , Babu Rajendran Prakash , Dhamodharan Raghavachari
Published: December 2012

A series of dodecyl‐based monofunctional trithiocarbonate chain transfer agents (CTAs) were successfully synthesized, toward the reversible addition‐fragmentations chain transfer (RAFT) polymerization of styrene. The CTAs were used as initiators for RAFT polymerization, in the absence of the conventional free radical initiator, at higher temperature. Polystyrene (PS) of narrow polydispersity index (PDI) is synthesized. Subsequently, poly(styrene‐b‐benzyl methacrylate) diblock and poly(styrene‐b‐benzyl methacrylate‐b‐2‐vinyl pyridine) triblock copolymers were synthesized from the PS macro‐RAFT agent by simply heating with the second and third monomer, respectively. These experiments suggest that it should be possible to control the RAFT polymerization initiated by a CTA through the adjustment of the temperature of polymerization in such manner that initiation is tailored to proceed at faster rate (at higher temperature) in comparison to propagation (lower temperature). For the specific CTAs studied in this work, the polymerization rate of styrene was high in the case of the reinitiating cyano (CN)‐substituted group (R group) compared to the other groups studied. The results further show that 4‐cyano pentanoic acid group is superior to the other R groups used for the RAFT polymerization of styrene, especially based on the polydispersity at a given conversion as well as the variation in the expected and experimental number‐average‐molecular weights. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013
Growth and characterization of site‐selective quantum dots
Authors: Helfrich Mathieu , Schroth Philipp , Grigoriev Daniil , Lazarev Sergey , Felici Roberto , Slobodskyy Taras , Baumbach Tilo , Schaadt Daniel M.
Published: December 2012

A review on the growth and characterization of site‐selective quantum dots (QDs) is presented. First, a theoretical model is used to describe the mechanism leading to the formation of QDs at pre‐defined locations. The structural properties of site‐selective QDs was revealed and their optical quality was tested. Various parameters, such as hole size, hole depth, or InAs amount, influencing the QD occupation and the QD size are discussed and possible ways to control these are presented.

magnified image

Ordered QD array with multiple dot nucleation (left) and single QD in dry etched hole (right).
Three‐dimensional radiation pattern measurement strategy for ground station antennas
Authors: Pedersen Michael Nygaard , Letschnik Jürgen , Schelde Lars , Karstoft Henrik , Schurig Fritz , Walter Ulrich
Published: December 2012

This article describes how to measure a three‐dimensional antenna radiation pattern and the most effective method to achieve this. We present a new automated three‐dimensional measurement scheme, inspired by the seed pattern of a sunflower seed head, where the seed placements are arranged in a way so that rotational symmetry is obtained to compromise the circular shape of a dish antenna radiation pattern in the three‐dimensional space. This new AU–TUM Antenna Radiation Measurement Strategy has produced superior results. It has been shown by this scheme that for instance the three‐dimensional transmission pattern of a dish antenna can be measured automatically and easily checked against present regulations. The generic AU–TUM Antenna Radiation Measurement Strategy was verified on a 4.8‐m Ka‐band dish antenna. It was concluded that a three‐dimensional radiation pattern can be measured two to thirteen times faster than the best performing current strategies. Copyright © 2012 John Wiley & Sons, Ltd.
Methods for dealing with time‐dependent confounding
Authors: Daniel R.M. , Cousens S.N. , De Stavola B.L. , Kenward M. G. , Sterne J. A. C.
Published: December 2012

Longitudinal studies, where data are repeatedly collected on subjects over a period, are common in medical research. When estimating the effect of a time‐varying treatment or exposure on an outcome of interest measured at a later time, standard methods fail to give consistent estimators in the presence of time‐varying confounders if those confounders are themselves affected by the treatment. Robins and colleagues have proposed several alternative methods that, provided certain assumptions hold, avoid the problems associated with standard approaches. They include the g‐computation formula, inverse probability weighted estimation of marginal structural models and g‐estimation of structural nested models. In this tutorial, we give a description of each of these methods, exploring the links and differences between them and the reasons for choosing one over the others in different settings. Copyright © 2012 John Wiley & Sons, Ltd.
Improving High‐Temperature Wear Resistance of Fe–Cr13–C Hardfacing Alloy by Nitrogen Alloying
Authors: Yang Ke , Bao Yefeng
Published: December 2012

Nitrogen alloying of Fe–Cr13–C hardfacing alloy produces marked precipitation strengthening to achieve an improvement in high‐temperature wear resistance. Two hardfacing alloys of Fe–Cr13–C (with and without nitrogen) are slid on carbon steel at high‐temperature of 600°C and high load of 600 N, and wear behaviors are studied systematically. It is found that abrasive wear occurrs on the surface of the hardfacing alloy due to abrasive action of crushed oxide particles coming from the surface of carbon steel on the high temperature. The wear resistance is determined by the size and distribution of precipitates. The results show that the hardfacing alloy can obtain a great increase in hardness and a marked decrease in wear depth of grooving due to the effect of carbonitirde precipitates. The high‐temperature wear resistance of the Fe–Cr13–C hardfacing alloy is improved by nitrogen alloying, and the wear mechanism is mainly plastic deformation with minimum depth of grooving caused by the oxide particles.
Bemessungsmodell zur Durchknöpftragfähigkeit von Sandwichelementen bei direkter Verankerung
Authors: Ungermann Dieter , Lübke Sebastian
Published: December 2012

Verankerungen in Sandwichelementen werden derzeit auf der Grundlage experimentell bestimmter Durchknöpftragfähigkeiten dimensioniert, da ein mechanisch basiertes Tragmodell fehlt. Im Rahmen eines Forschungsvorhabens wurde ein analytisches Modell zum Nachweis von Direktverankerungen entwickelt, welches mit Hilfe umfangreicher numerischer und experimenteller Untersuchungen bestätigt werden konnte.

Design model for pull‐through resistance of direct fastenings in sandwich panels. Fastenings of sandwich panels are designed based on experimentally determined pull‐through resistances, because a mechanically based model does not exist. In the context of a research project an analytical design model of direct fastenings has been developed and verified by extensive numerical and experimental investigations.
Wand‐ und Deckenkonstruktionen im Kühlhausbau
Authors: Möller Ralf
Published: December 2012

Für die statische Berechnung und Bemessung der Sandwich‐Fassadenelemente von Kühlhäusern liegen zwischenzeitlich anerkannte Regeln vor, die Schäden an der Konstruktion infolge früher oft beobachteter Überbeanspruchungen der äußeren Deckschale verhindern. Der Innenausbau von Kühlanlagen wird zur Zeit in der Regel unter Ausschluss der Bauaufsicht durchgeführt. In vielen Fällen wird auf die Anfertigung von statischen Berechnungen und Festigkeitsnachweisen zugunsten langjähriger Erfahrungen der errichtenden Firmen vollständig verzichtet. Das Sicherheitsniveau, welches dann mit derartigen Konstruktionen einhergeht, ist – obwohl man sich offensichtlich oft in Grenzbereichen bewegt – nicht bekannt.

Der Wunsch nach immer größeren Spannweiten und wirtschaftlicheren Konstruktionen nötigt den verantwortlichen Bauleiter oder den Statiker oft zu einem Vorgehen, welches durch das Baurecht nicht abgedeckt ist und macht diesen Bereich zu einem lohnenden Forschungsobjekt. Es ist die Absicht zu zeigen, wie man mit relativ geringem Aufwand auf ingenieurmäßiger Basis zu Lösungen kommen kann – vorausgesetzt, die o. a. Lücken in der Technik werden geschlossen.

Wall and ceiling constructions in cold stores. Meanwhile, there are accepted rules regarding the structural analysis and dimensioning of sandwich façade elements for cold stores, which prevent damage to the structure resulting from excessive loads of the outer cover sheet such as used to frequently be observed. The interior finishes of cooling systems are currently usually made without the building authorities being involved. Often the companies in charge of construction completely dispense with structural analyses or proofs of rigidity and instead apply their long‐standing experience. The safety level of these structures is not known, even though they obviously come near to stability limits.

The demand for ever larger spans and ever more cost‐effective structures often pushes the construction supervisor or structural engineer to use an approach which is not covered by building legislation, making this area a rewarding subject for study. Our aim is to demonstrate how solutions can be achieved with a limited effort using a sound engineering basis, provided the identified technology gaps can be closed.
Stabilisierung von Bauteilen durch Sandwichelemente
Authors: Käpplein Saskia , Ummenhofer Thomas , Berner Klaus
Published: December 2012

Aufgrund ihrer großen Schubsteifigkeit in Plattenebene können Sandwichelemente ihre Unterkonstruktion, z. B. Pfetten und Wandriegel, gegen seitliches Ausweichen stabilisieren. Bisher fehlen jedoch praxistaugliche Grundlagen zur Ermittlung der Schubsteifigkeit der Sandwichelemente, die es ermöglichen, den Stabilisierungseffekt rechnerisch z. B. bei der Bemessung von Pfetten zu berücksichtigen, wie es bei Trapez‐ und Kassettenprofilen üblich ist. Im Aufsatz wird ein Berechnungsverfahren vorgestellt, mit dem die zur Stabilisierung der Unterkonstruktion zur Verfügung stehende Schubsteifigkeit der Sandwichelemente ermittelt werden kann. Aus der Stabilisierung resultieren planmäßige zusätzliche Kräfte in den Verbindungen zwischen Sandwichelement und Unterkonstruktion. Die Ermittlung dieser Beanspruchungen wird erläutert, um eine entsprechende Bemessung der Verbindungen durchführen zu können.

Stabilization of the substructure by sandwich panels. Because of their high in‐plane shear stiffness sandwich panels can stabilize their substructure, e. g. purlins and bay rails. But until now, there is a lack of clear design rules, which allow to determine the shear stiffness and to consider the stabilizing effect in the design of the substructure, as it is common practice for trapezoidal and cassette profiles. The present paper introduces a calculation procedure to determine the shear stiffness available for stabilization. Stabilization of the substructure causes additional forces in the fastenings between sandwich panel and substructure. The determination of these forces is also explained so that the fastenings can be designed properly.
Cultural emergence: Theorizing culture in and from the margins of science education
Authors: Wood Nathan Brent , Erichsen Elizabeth Anne , Anicha Cali L.
Published: December 2012

This special issue of the Journal of Research in Science Teaching seeks to explore conceptualizations of culture that address contemporary challenges in science education. Toward this end, we unite two theoretical perspectives to advance a conceptualization of culture as a complex system, emerging from iterative processes of cultural bricolage, that is, a cyclic (re)application, and adaptation via approximation, of cultural tools to contexts as they uniquely arise. This conception of culture provides a means for transmission of culture from one individual to another, but it also allows for substantial diversity of individual perspectives within a cultural group in ways that supra‐individual conceptions of culture do not. What is more, this diversity of individuals provides a mechanism for cultural evolution and simultaneously allows for an individual to be shaped by culture and culture to be shaped by the individual. Culture, in this conception, is understood to be an emergent phenomenon, built up from iterative application of cultural software. Implications are considered with respect to further development toward a theoretical framework; educational research agenda and methodology; and education policy—particularly in the context of science education. © 2012 Wiley Periodicals, Inc. J Res Sci Teach 50:122–136, 2013
Transitioning students out of college: The senior LC in psychology at Wagner College
Authors: Nolan Laurence J. , Jenkins Steve M.
Published: December 2012

This chapter describes the senior learning community in psychology at Wagner College, which is an example of a discipline‐specific curriculum‐based learning community (LC). This LC acts both as a capstone to the undergraduate experience and as a transition for students from college to career. We describe the components of the LC, their development, our attempts to integrate them, and how they might be applied in other intradisciplinary LCs.
Residential learning communities centered within a discipline: The Psychology Early Awareness Program
Authors: Grills Cheryl N. , Fingerhut Adam W. , Thadani Vandana , Machón Ricardo Arturo
Published: December 2012

This chapter describes the Psychology Early Awareness Program (PEAP) at Loyola Marymount University, a residential learning community centered within a discipline. We discuss the theory that supports the value of living‐learning communities, describe how this guided the development of PEAP, and summarize the benefits of this approach.
Virtual learning communities centered within a discipline: Future directions
Authors: Blanchard Anita L. , Cook James R.
Published: December 2012

Virtual learning communities (VLCs) provide a new vehicle
for creating connections among stakeholders within academic disciplines and departments. This chapter describes the innovative use of information and computer technology (ICT) to create VLCs that can extend and enhance the impact of the traditional face‐to‐face learning communities described in preceding chapters.
Patient Satisfaction, Chronic Pain, and Functional Status following Laparoscopic Ventral Hernia Repair
Authors: Liang Mike K. , Clapp Marissa , Li Linda T. , Berger Rachel L. , Hicks Stephanie C. , Awad Samir
Published: December 2012

Background

Ventral hernia repairs are one of the most common surgeries performed. Symptoms are the most common motivation for repair. Unfortunately, outcomes of repair are typically measured in recurrence and infection rather than patient focused results. We correlated factors associated with decreased patient satisfaction, chronic pain, and diminished functional status following laparoscopic ventral hernia repair (LVHR)

Methods

A retrospective study of 201 patients from two affiliated institutions was performed. Patient satisfaction, chronic abdominal pain, pain scores, and Activities Assessment Scale results were obtained in 122 patients. Results were compared with univariate and multivariate analysis.

Results

Thirty‐two (25.4 %) patients were dissatisfied with their LVHR while 21 (17.2 %) patients had chronic abdominal pain and 32 (26.2 %) patients had poor functional status following LVHR. Decreased patient satisfaction was associated with perception of poor cosmetic outcome (OR 17.3), eventration (OR 10.2), and chronic pain (OR 1.4). Chronic abdominal pain following LVHR was associated with incisional hernia (OR 9.0), recurrence (OR 4.3), eventration (OR 6.0), mesh type (OR 1.9), or ethnicity (OR 0.10). Decreased functional status with LVHR was associated with mesh type used (OR 3.7), alcohol abuse (OR 3.4), chronic abdominal pain (OR 1.3), and age (OR 1.1).

Conclusions

One‐fourth of patients have poor quality outcome following LVHR. These outcomes are affected by perception of cosmesis, eventration, chronic pain, hernia type, recurrence, mesh type, and patient characteristics/co‐morbidities. Closing central defects and judicious mesh selection may improve patient satisfaction and function. Focus on patient‐centered outcomes is warranted.
Transient epileptiform signaling during neuronal network development: regulation by external stimulation and bimodal GABAergic activity
Authors: Zemianek Jill M. , Shultz Abraham M. , Lee Sangmook , Guaraldi Mary , Yanco Holly A. , Shea Thomas B.
Published: December 2012

A predominance of excitatory activity, with protracted appearance of inhibitory activity, accompanies cortical neuronal development. It is unclear whether or not inhibitory neuronal activity is solicited exclusively by excitatory neurons or whether the transient excitatory activity displayed by developing GABAergic neurons contributes to an excitatory threshold that fosters their conversion to inhibitory activity. We addressed this possibility by culturing murine embryonic neurons on multi‐electrode arrays. A wave of individual 0.2–0.4 mV signals (“spikes”) appeared between approx. 20–30 days in culture, then declined. A transient wave of high amplitude (>0.5 mV) epileptiform activity coincided with the developmental decline in spikes. Bursts (clusters of ≥3 low‐amplitude spikes within 0.7 s prior to returning to baseline) persisted following this decline.

Addition of the GABAergic antagonist bicuculline initially had no effect on signaling, consistent with delayed development of GABAergic synapses. This was followed by a period in which bicuculline inhibited overall signaling, confirming that GABAergic neurons initially display excitatory activity in ex vivo networks. Following the transient developmental wave of epileptiform signaling, bicuculline induced a resurgence of epileptiform signaling, indicating that GABAergic neurons at this point displayed inhibitory activity. The appearance of transition after the developmental and decline of epileptiform activity, rather than immediately after the developmental decline in lower‐amplitude spikes, suggests that the initial excitatory activity of GABAergic neurons contributes to their transition into inhibitory neurons, and that inhibitory GABAergic activity is essential for network development.

Prior studies indicate that a minority (25%) of neurons in these cultures were GABAergic, suggesting that inhibitory neurons regulate multiple excitatory neurons. A similar robust increase in signaling following cessation of inhibitory activity in an artificial neural network containing 20% inhibitory neurons supported this conclusion. Even a minor perturbation in GABAergic function may therefore foster initiation and/or amplification of seizure activity, as well as perturbations in long‐term potentiation.
Epigenetic control of neurotransmitter expression in olfactory bulb interneurons
Authors: Banerjee Kasturi , Akiba Yosuke , Baker Harriet , Cave John W.
Published: December 2012

Defining the molecular mechanisms that underlie development and maintenance of neuronal phenotypic diversity in the CNS is a fundamental challenge in developmental neurobiology. The vast majority of olfactory bulb (OB) interneurons are GABAergic and this neurotransmitter phenotype is specified in migrating neuroblasts by transcription of either or both glutamic acid decarboxylase 1 (Gad1) and Gad2. A subset of OB interneurons also co‐express dopamine, but transcriptional repression of tyrosine hydroxylase (Th) suppresses the dopaminergic phenotype until these neurons terminally differentiate. In mature OB interneurons, GABA and dopamine levels are modulated by odorant‐induced synaptic activity‐dependent regulation of Gad1 and Th transcription. The molecular mechanisms that specify and maintain the GABAergic and dopaminergic phenotypes in the OB are not clearly delineated. In this report, we review previous studies and present novel findings that provide insight into the contribution of epigenetic regulatory mechanisms for controlling expression of these neurotransmitter phenotypes in the OB. We show that HDAC enzymes suppress the dopaminergic phenotype in migrating neuroblasts by repressing Th transcription. In the mature interneurons, both Th and Gad1 transcription levels are modulated by synaptic activity‐dependent recruitment of acetylated Histone H3 on both the Th and Gad1 proximal promoters. We also show that HDAC2 has the opposite transcriptional response to odorant‐induced synaptic activity when compared to Th and Gad1. These findings suggest that HDAC2 mediates, in part, the activity‐dependent chromatin remodeling of the Th and Gad1 proximal promoters in mature OB interneurons.
Evolution ofScaphinotus petersi(Coleoptera: Carabidae) and the role of climate and geography in the Madrean sky islands of southeastern Arizona, USA
Authors: Mitchell Sara Gran , Ober Karen A.
Published: December 2012

Geographically isolated environments such as the conifer forests atop the Madrean “sky islands” in southeastern Arizona provide natural laboratories for studying factors involved in speciation and origins of biodiversity. Using molecular and geospatial analyses, we examine beetle population phylogeny, regional climate records, and the Quaternary paleobiogeography of forests to evaluate four hypothetical scenarios regarding the current geographic and population genetic patterns ofScaphinotus petersi.Scaphinotus petersiis a large, flightless beetle that resides in the Madrean conifer forests above ~ 1900 m asl. Our results do not support the current hypothesis thatS.petersipopulations found on seven separate mountain ranges are genetically distinct and separated as temperatures warmed after the Last Glacial Maximum (LGM). Rather, we show that only some of the ranges hold genetically distinct populations, and the timing of separation among the populations does not appear to coincide with specific climatic events such as warming trends. In addition, we show that predicted changes to the climate of the Madrean sky islands may result in the disappearance ofS.petersifrom some of the lower ranges by the end of this century.
XVII.—An Analytical Theory of the Equilibrium of an Isotropic Elastic Rod of Circular Section
Authors: Dougall John
Published: December 2012

The main purpose of the following investigation is to improve the existing Approximate Theory of Beams by bringing it into closer relationship than has hitherto been done with exact solutions of the fundamental differential equations of equilibrium. In its aim, method, and results the paper closely resembles one already published in these Transactions on the corresponding Theory for Plates (vol. xli., 1904). It is less comprehensive than the latter paper, as it deals only with a beam of circular section; but the analysis is of such a nature that the chief results can be extended almost immediately to a beam of any form of section, on the assumption merely of certain Existence Theorems.
Measuring the Curie temperature
Authors: Fabian K. , Shcherbakov V. P. , McEnroe S. A.
Published: December 2012

Curie point temperatures (TC) of natural and synthetic magnetic materials are commonly determined in rock magnetism by several measurement methods that can be mutually incompatible and may lead to inconsistent results. Here the common evaluation routines for high‐temperature magnetization and magnetic initial susceptibility curves are analyzed and revised based on Landau's theory of second‐order phase transitions. It is confirmed that in high‐field magnetization curves TC corresponds to the inflection point, below the temperature of maximum curvature or the double‐tangent intersection point. At least four different physical processes contribute to the initial magnetic susceptibility near the ordering temperature. They include variation of saturation magnetization, superparamagnetic behavior, magnetization rotation, and magnetic domain wall motion. Because each of these processes may influence the apparent position of TC, initial susceptibility and high‐field curves can yield deviating estimates of TC. A new procedure is proposed to efficiently determine the temperature variation of several magnetic parameters on a vibrating‐sample magnetometer, by repeatedly measuring quarter‐hysteresis loops during a single heating cycle. This procedure takes measurements during the inevitable waiting time necessary for thermal equilibration of the sample, whereby it is not slower than the commonly performed measurements on a Curie balance. However, it returns saturation magnetization, saturation remanence, high‐field and low‐field slopes, and other parameters as a function of temperature, which provide independent information about TC and other sample properties.
Trends and variations of ocean surface latent heat flux: Results from GSSTF2c data set
Authors: Gao Si , Chiu Long S. , Shie Chung‐Lin
Published: December 2012

Trends and variations of Goddard Satellite‐based Surface Turbulent Fluxes (GSSTF) version 2c (GSSTF2c) latent heat flux (LHF) are examined. This version of LHF takes account of the correction in Earth incidence angle. The trend of global mean LHF for GSSTF2c is much reduced relative to GSSTF version 2b Set 1 and Set 2 for the same period 1988–2008. Temporal increase of GSSTF2c LHF in the two decades is 11.0%, in which 3.1%, 5.8%, and 2.1% are attributed to the increase in wind, the increase in sea surface saturated air humidity, and the decrease in near‐surface air humidity, respectively. The first empirical orthogonal function of LHF is a conventional El Niño Southern Oscillation (ENSO) mode. However, the trends in LHF are independent of conventional ENSO phenomena. After removing ENSO signal, the pattern of LHF trends is primarily determined by the pattern of air‐sea humidity difference trends.
The Heppner‐Maynard Boundary measured by SuperDARN as a proxy for the latitude of the auroral oval
Authors: Imber S. M. , Milan S. E. , Lester M.
Published: December 2012

We present a statistical study relating the latitude of the auroral oval measured by the Imager for Magnetopause‐to‐Aurora Global Exploration (IMAGE) SI‐12 proton auroral camera to that of the Heppner‐Maynard Boundary (HMB) determined from Super Dual Auroral Radar Network (SuperDARN) data during the period 2000–2002. The HMB represents the latitudinal extent of the ionospheric convection pattern. The oval latitude from the proton auroral images is determined using the method of Milanet al. (2009a), which fits a circle centered on a point 2° duskward and 5° antisunward of the magnetic pole. The auroral latitude at midnight is determined for those images where the concurrent SuperDARN northern hemisphere maps contain more than 200 data points such that the HMB is well‐defined. The statistical study comprises over 198,000 two‐minute intervals, and we find that the HMB is located on average 2.2° equatorward of the proton auroral latitude. A superposed epoch analysis of over 2500 substorms suggests that the separation between the HMB and the oval latitude increases slightly during periods of high geomagnetic activity. We suggest that during intervals where there are no auroral images available, the HMB latitude and motion could be used as a proxy for that of the aurora, and therefore provide information about motions of the open/closed field line boundary.
Simulated decadal variability of the meridional overturning circulation across the A25‐Ovide section
Authors: Desbruyères Damien , Thierry Virginie , Mercier Herlé
Published: December 2012

Decadal changes of the meridional overturning circulation (MOC) at the A25‐Ovide section between Portugal and Greenland are investigated in a numerical simulation forced by atmospheric reanalysis data for the period 1965–2004. The intensity, composition, and structure of the upper MOC limb are assessed using a Lagrangian analysis tool. Its mean transport is fed by water masses of two distinct origins: the subtropics and the Labrador Sea. Two vertical overturning cells are consequently identified: a subtropical cell connecting low and high latitudes (12 Sv, 1 Sv = 106 m3 s–1) and a cell internal to the subpolar gyre (4 Sv). The decadal MOC variability is associated with synchronized transport changes of the subtropical and subpolar inflow within the North Atlantic Current (NAC). The varying strength of the MOC is further related to changes in the upper horizontal transport distribution. When the MOC is in a strong phase (early 1990s), the northern branch of the NAC in the Iceland Basin is strong while the southern branch at the Rockall Trough entrance is relatively weak. The inverse situation holds for a persistent weak MOC state (1970s). Contrary to the conclusions of earlier studies, variability in the strength and shape of the subpolar gyre does not stand as the main driver of the changing NAC structure, which is largely induced by the horizontal variability of the subtropical inflow. Additionally, the recently shown intrusion of subtropical waters into the northeastern Atlantic (late 1960s, early 1980s, and 2000s) are shown to primarily occur during periods of weak MOC circulation at A25‐Ovide.
The role of acids in electrical conduction through ice
Authors: Stillman David E. , MacGregor Joseph A. , Grimm Robert E.
Published: December 2012

Electrical conduction through meteoric polar ice is controlled by soluble impurities that originate mostly from sea salt, biomass burning, and volcanic eruptions. The strongest conductivity response is to acids, yet the mechanism causing this response has been unclear. Here we elucidate conduction mechanisms in ice using broadband dielectric spectroscopy of meteoric polar ice cores. We find that conduction through polycrystalline polar ice is consistent with Jaccard theory for migration of charged protonic point defects through single ice crystals, except that bulk DC conduction is impeded by grain boundaries. Neither our observations nor modeling using Archie's Law support the hypothesis that grain‐boundary networks of unfrozen acids cause significant electrolytic conduction. Common electrical logs of ice cores (by electrical conductivity measurement [ECM] or dielectric profiling [DEP]) and the attenuation of radio waves in ice sheets thus respond to protonic point defects only. This response implies that joint interpretation of electrical and chemical logs can determine impurity partitioning between the lattice and grain boundaries or inclusions. For example, in the Greenland Ice Core Project (GRIP) ice core from central Greenland, on average more than half of the available lattice‐soluble impurities (H+, Cl–, NH4+) create defects. Understanding this partitioning could help further resolve the nature of past changes in atmospheric chemistry.
Enhanced benthic response to upwelling of the Indonesian Throughflow onto the southern shelf of Timor‐Leste, Timor Sea
Authors: Alongi Daniel M. , Brinkman Richard , Trott Lindsay A. , da Silva Fernando , Pereira Francisco , Wagey Tonny
Published: December 2012

Benthic microbial metabolism and bacterial diagenetic pathways were measured along the southern shelf of Timor‐Leste during an upwelling event in the winter SE monsoon season. Vertical profiles of water properties and bottom water nutrient concentrations, and operational ocean modeling showed subsurface upwelling from the Indonesian Throughflow (ITF) along the southern shelf west of longitude 126°25′E and surface upwelling at the far eastern end of the shelf. Warm surface waters above the halocline had salinities of 33.6 to 33.9 overlying cooler ITF water with salinities of 34.4 to 34.6. Beneath the zone of subsurface upwelling and stratification, sediment chlorophyll a (range: 2.8–4.4 µg g−1) and phaeopigment (range: 4.5–7.0 µg g−1) concentrations were sufficient to fuel very rapid rates of benthic oxygen consumption (range: 89.9–142.3 mmol m−2 day−1) and dissolved inorganic carbon (DIC) release (range: 108.1–148.9 mmol m−2 day−1) across the sediment‐water interface, and DIC (range: 94.7–142.5 mmol m−2 day−1) and NH4+ (range: 13.3–19.9 mmol m−2 day−1) production from incubated surface (0–10 cm) sediments. Molar ratios of DIC/NH4+ production were lower (range: 6.6–7.7) in fine‐grained sediments under the subsurface upwelling regime than in sandy, possibly scoured sediments under surface upwelling (range: 11.9–21.2) where there was no evidence of benthic enrichment. It is proposed that subsurface upwelling along the widest portions of the shelf stimulates phytoplankton production, leading to deposition of fresh phytodetritus that is rapidly decomposed on the seafloor. These zones of high biological activity may attract and support large populations of pelagic fish and cetaceans that have been caught for centuries along the south coast.
The Engine of Well-Being
Authors: Jayawickreme Eranda , Forgeard Marie J. C. , Seligman Martin E. P.
Published: December 2012

The study of well-being is hampered by the multiplicity of approaches, but focusing on a single approach begs the question of what “well-being” really is. We analyze how well-being is defined according to the three main kinds of theories: “Liking” approaches (generally adopted by psychologists), “Wanting” approaches (predominant among economists), and “Needing” approaches (used in both public policy and psychology). We propose an integrative framework, the engine model of well-being, drawing on Seligman (Seligman, M. E. P., 2011 , Flourish. New York, NY: The Free Press) and Sen's (Sen, A. K., 1999 , Development as freedom. Oxford, England: Oxford University Press) emphasis on the plurality of this construct by distinguishing among (a) inputs (resources that enable well-being), (b) processes (internal states of mechanisms influencing well-being), and (c) outcomes (the intrinsically valuable behaviors that reflect the attainment of well-being). We discuss implications for research, measurement, and interventions.
T‐cell intrinsic and extrinsic mechanisms of p27Kip1 in the regulation of CD8 T‐cell memory
Authors: Jatzek Anna , Marie Tejera Melba , Plisch Erin H , Fero Matthew L , Suresh M
Published: December 2012

CD8 T cells exhibit dynamic alterations in proliferation and apoptosis during various phases of the CD8 T‐cell response, but the mechanisms that regulate cellular proliferation from the standpoint of CD8 T‐cell memory are not well defined. The cyclin‐dependent kinase inhibitor p27Kip1 functions as a negative regulator of the cell cycle in T cells, and it has been implicated in regulating cellular processes, including differentiation, transcription and migration. Here, we investigated whether p27Kip1 regulates CD8 T‐cell memory by T‐cell‐intrinsic or T‐cell‐extrinsic mechanisms, by conditional ablation of p27Kip1 in T cells or non‐T cells. Studies of T‐cell responses to an acute viral infection show that p27Kip1 negatively regulates the proliferation of CD8 T cells by T‐cell‐intrinsic mechanisms. However, the enhanced proliferation of CD8 T cells induced by T‐cell‐specific p27Kip1 deficiency minimally affects the primary expansion or the magnitude of CD8 T‐cell memory. Unexpectedly, p27Kip1 ablation in non‐T cells markedly augmented the number of high‐quality memory CD8 T cells by enhancing the accumulation of memory precursor effector cells without increasing their proliferation. Further studies show that p27Kip1 deficiency in immunizing dendritic cells fail to enhance CD8 T‐cell memory. Nevertheless, we have delineated the T‐cell‐intrinsic, anti‐proliferative activities of p27Kip1 in CD8 T cells from its role as a factor in non‐T cells that restricts the development of CD8 T‐cell memory. These findings have implications in vaccine development and understanding the mechanisms that maintain T‐cell homeostasis.
Barrier height distribution and dipolar relaxation in metal-insulator-semiconductor junctions with molecular insulator: Ageing effects
Authors: Fadjie-Djomkam A. B. , Ababou-Girard S. , Godet C.
Published: December 2012

Electrical transport through molecular monolayers being very sensitive to disorder effects, admittance and current density characteristics of Hg//C12H25 – n Si junctions incorporating covalently bonded n-alkyl molecular layers, were investigated at low temperature (150–300 K), in the as-grafted state and after ageing at the ambient. This comparison reveals local oxidation effects both at the submicron scale in the effective barrier height distribution and at the molecular scale in the dipolar relaxation. In the bias range dominated by thermionic emission and modified by the tunnel barrier (TB) attenuation, exp(−β0dT), where dT is the thickness of the molecular tunnel barrier and β0 is the inverse attenuation length at zero applied bias, some excess current is attributed to a distribution of low barrier height patches. Complementary methods are used to analyze the current density J(V, T) characteristics of metal-insulator-semiconductor tunnel diodes. Assuming a Gaussian distribution of barrier heights centered at qΦB provides an analytical expression of the effective barrier height, qΦEFF(T)=qΦB+(kT)β0dT−(qδΦ)2/2kT; this allows fitting of the distribution standard deviation δΦ and tunnel parameter (β0dT) over a wide temperature range. In a more realistic modeling including the voltage dependence of barrier height and circular patch area, the so-called “pinch-off” effect is described by a distribution of parameter γ=3(ΔPRP2/4)1/3, which combines interface potential modulation and patch area variations. An arbitrary distribution of γ values, fitted to low-temperature J(V) data, is equally well described by Gaussian or exponential functions. Ageing in air also increases the interface oxidation of Si substrate and affects the density of localized states near mid gap, which typically rises to the high 1011 eV−1 cm−2 range, as compared with DS < 1011 eV−1 cm−2 in the as-grafted state. The bias-independent relaxation observed near 1 kHz at low temperature may be attributed either to dipoles in the alkyl chain induced by the strong permanent dipoles of interface silicon oxide or to a local relaxation of water molecules trapped at the OML/silicon interface. The respective roles of SiO2 formation and water physisorption on the decrease of patch barrier height are also discussed.