bluuebunny/crossref_metadata_2025 huggingface dataset:
Endotoxin Tolerance Represents a Distinctive State of Alternative Polarization (M2) in Human Mononuclear Cells
Authors: Pena Olga M. , Pistolic Jelena , Raj Disha , Fjell Christopher D. , Hancock Robert E. W.
Published: May 2011

Classical (M1) and alternative (M2) polarization of mononuclear cells (MNCs) such as monocyte and macrophages is known to occur in response to challenges within a microenvironment, like the encounter of a pathogen. LPS, also known as endotoxin, is a potent inducer of inflammation and M1 polarization. LPS can also generate an effect in MNCs known as endotoxin tolerance, defined as the reduced capacity of a cell to respond to LPS activation after an initial exposure to this stimulus. Using systems biology approaches in PBMCs, monocytes, and monocyte-derived macrophages involving microarrays and advanced bioinformatic analysis, we determined that gene responses during endotoxin tolerance were similar to those found during M2 polarization, featuring gene and protein expression critical for the development of key M2 MNC functions, including reduced production of proinflammatory mediators, expression of genes involved in phagocytosis, as well as tissue remodeling. Moreover, expression of different metallothionein gene isoforms, known for their role in the control of oxidative stress and in immunomodulation, were also found to be consistently upregulated during endotoxin tolerance. These results demonstrate that after an initial inflammatory stimulus, human MNCs undergo an M2 polarization probably to control hyperinflammation and heal the affected tissue.
Chronic Helminth Infection Promotes Immune Regulation In Vivo through Dominance of CD11cloCD103− Dendritic Cells
Authors: Smith Katherine A. , Hochweller Kristin , Hämmerling Günter J. , Boon Louis , MacDonald Andrew S. , Maizels Rick M.
Published: May 2011

Gastrointestinal helminth infections are extremely prevalent in many human populations and are associated with downmodulated immune responsiveness. In the experimental model system of Heligmosomoides polygyrus, a chronic infection establishes in mice, accompanied by a modulated Th2 response and increased regulatory T cell (Treg) activity. To determine if dendritic cell (DC) populations in the lymph nodes draining the intestine are responsible for the regulatory effects of chronic infection, we first identified a population of CD11clo nonplasmacytoid DCs that expand after chronic H. polygyrus infection. The CD11clo DCs are underrepresented in magnetic bead-sorted preparations and spared from deletion in CD11c-diptheria toxin receptor mice. After infection, CD11clo DCs did not express CD8, CD103, PDCA, or Siglec-H and were poorly responsive to TLR stimuli. In DC/T cell cocultures, CD11clo DCs from naive and H. polygyrus-infected mice could process and present protein Ag, but induced lower levels of Ag-specific CD4+ T cell proliferation and effector cytokine production, and generated higher percentages of Foxp3+ T cells in the presence of TGF-β. Treg generation was also dependent on retinoic acid receptor signaling. In vivo, depletion of CD11chi DCs further favored the dominance of the CD11clo DC phenotype. After CD11chi DC depletion, effector responses were inhibited dramatically, but the expansion in Treg numbers after H. polygyrus infection was barely compromised, showing a significantly higher regulatory/effector CD4+ T cell ratio compared with that of CD11chi DC-intact animals. Thus, the proregulatory environment of chronic intestinal helminth infection is associated with the in vivo predominance of a newly defined phenotype of CD11clo tolerogenic DCs.
Mosaic HIV-1 Gag Antigens Can Be Processed and Presented to Human HIV-Specific CD8+ T Cells
Authors: Ndhlovu Zaza M. , Piechocka-Trocha Alicja , Vine Seanna , McMullen Ashley , Koofhethile Kegakilwe C. , Goulder Phillip J. R. , Ndung’u Thumbi , Barouch Dan H. , Walker Bruce D.
Published: May 2011

Polyvalent mosaic HIV immunogens offer a potential solution for generating vaccines that can elicit immune responses against genetically diverse viruses. However, it is unclear whether key T cell epitopes can be processed and presented from these synthetic Ags and recognized by epitope-specific human T cells. In this study, we tested the ability of mosaic HIV immunogens expressed by recombinant, replication-incompetent adenovirus serotype 26 vectors to process and present major HIV clade B and clade C CD8 T cell epitopes in human cells. A bivalent mosaic vaccine expressing HIV Gag sequences was used to transduce PBMCs from 12 HIV-1–infected individuals from the United States and 10 HIV-1–infected individuals from South Africa; intracellular cytokine staining, together with tetramer staining, was used to assess the ability of mosaic Gag Ags to stimulate pre-existing memory responses compared with natural clade B and C vectors. Mosaic Gag Ags expressed all eight clade B epitopes tested in 12 United States subjects and all 5 clade C epitopes tested in 10 South African subjects. Overall, the magnitude of cytokine production induced by stimulation with mosaic Ags was comparable to clade B and clade C Ags tested, but the mosaic Ags elicited greater cross-clade recognition. Additionally, mosaic Ags induced HIV-specific CD4 T cell responses. Our studies demonstrate that mosaic Ags express major clade B and clade C viral T cell epitopes in human cells, as well as support the evaluation of mosaic HIV-1 vaccines in humans.
Cutting Edge: Human Regulatory T Cells Require IL-35 To Mediate Suppression and Infectious Tolerance
Authors: Chaturvedi Vandana , Collison Lauren W. , Guy Clifford S. , Workman Creg J. , Vignali Dario A. A.
Published: May 2011

Human regulatory T cells (Treg) are essential for the maintenance of immune tolerance. However, the mechanisms they use to mediate suppression remain controversial. Although IL-35 has been shown to play an important role in Treg-mediated suppression in mice, recent studies have questioned its relevance in human Treg. In this study, we show that human Treg express and require IL-35 for maximal suppressive capacity. Substantial upregulation of EBI3 and IL12A, but not IL10 and TGFB, was observed in activated human Treg compared with conventional T cells (Tconv). Contact-independent Treg-mediated suppression was IL-35 dependent and did not require IL-10 or TGF-β. Lastly, human Treg-mediated suppression led to the conversion of the suppressed Tconv into iTr35 cells, an IL-35–induced Treg population, in an IL-35–dependent manner. Thus, IL-35 contributes to human Treg-mediated suppression, and its conversion of suppressed target Tconv into IL-35–induced Treg may contribute to infectious tolerance.
Summary of the 2010 AHPBA/SSO/SSAT Consensus Conference on HCC
Authors: Munene Gitonga , Vauthey Jean-Nicolas , Dixon Elijah
Published: May 2011

Under the auspices of the American Hepato-Pancreato-Biliary Association, an expert consensus conference was convened in January 2010 on the multidisciplinary management of hepatocellular carcinoma. The goals of the conference were to address knowledge gaps in the optimal preparation of patients with HCC for operative therapy, best methods to control HCC while awaiting liver transplantation, and developing a multidisciplinary approach to these patients with implementation of novel systemic therapies.
Central Ossifying Fibroma, Periapical Cemento-Osseous Dysplasia and Complex Odontoma Cccurring in the Same Jaw
Authors: Agha Hosseini Farzaneh , Moslemi Elham
Published: May 2011

Central ossifying fibroma is a rare, benign fibro-osseous lesion that arises from the periodontal ligament. Periapical cemento-osseous dysplasia is another variant of fibro-osseous lesion which occurs in the anterior region of the mandible of females. Odontoma is a benign odontogenic tumor that contains enamel, dentine cement and pulp tissue. A 46-year-old woman was referred to the Department of Oral Medicine, School of Dentistry, Tehran University of Medical Sciences, with two nonpainful swellings on both sides of the mandible, which had been slowly growing over a period of one year. Our differential diagnosis was florid cemento-osseous dysplasia, focal cemento-osseous dysplasia for the right side, complex odontoma for the left side and periapical cement-osseous dysplasia for the anterior side. The historical feature revealed ossifying fibroma, complex odontoma and periapical cemento-osseous dysplasia. The occurrence of these three lesions in the same jaw has been rarely reported in the literature. The relationship between the occurrence of these three lesions is not obvious it could be coincidental. It seems that more case reports are needed to establish the relationship between them.
Recent Advances in β-Thalassemias
Authors: Cao Antonio , Moi Paolo , Galanello Renzo
Published: May 2011

β-thalassemias, a group of autosomal recessive disorders resulting from reduced or absent production of β-globin chains from the β-globin locus, are very heterogeneous at the molecular level (for review see Weatherall & Clegg, 2001 and Cao & Galanello).1-2 More than 200 disease-causing mutations have been described to date. The large majority of mutations are simple nucleotide substitutions or deletions or insertions of oligonucleotides leading to frameshift. Rarely the β-thalassemias are the result of gross gene deletions. Homozygosity for β-thalassemia usually leads to the severe transfusion-dependent phenotype of thalassemia major. Treatment with a regular transfusion program and chelation therapy, aimed at reducing the transfusion iron-overload allows for normal growth and development and extends the life expectancy into the third to fifth decade. Bone marrow or cord blood transplantation (BMT) from an HLA-identical sib represent an alternative to traditional transfusion and chelation therapy. More rarely the homozygous state for β-thalassemia leads to the phenotype of thalassemia intermedia. Individuals with thalassemia intermedia present later, and have milder anemia and only rarely require transfusion. However also patients with thalassemia intermedia are at risk to develop iron overload secondary to increased intestinal iron absorption because of ineffective erythropoiesis. In the last few years there has been a dramatic advancement in the field of chelation therapy, genetic factors ameliorating the clinical phenotype, hemoglobin switching, gene therapy with lentiviral vectors and development of embryonic-like stem cells obtained by transfection and reprogramming differentiated somatic cells with key regulatory factors. All these developments, which are the topics of this review, may lead in the long term to advances in the traditional and in the gene and stem-cell-based therapy.
Sandstone geomorphology of the Golden Gate Highlands National Park, South Africa, in a global context
Authors: Grab Stefan W. , Goudie Andrew S. , Viles Heather A. , Webb Nicola
Published: May 2011

The Golden Gate Highlands National Park (GGHNP) is well known for its impressive sandstone formations. While previous geoscience research in the park has focused on geology, palaeontology, slope forms and the prominent lichen weathering, remarkably little has been written on the diversity and possible origins of sandstone phenomena in the region. The objectives of this study were (1) to present a geomorphological map of prominent and interesting landforms for particular portions of the park and (2) to document the variety of macro- and microscale sandstone formations observed. During field work, we undertook global positioning system measurements to map landforms and, in addition, measured the dimensions of several landform types. A Schmidt hammer was used to conduct rock hardness tests at a variety of localities and lithologies for comparative purposes. We indentified and mapped 27 macro- and microscale sandstone landforms, of which 17 are described in detail. It is demonstrated that for the most part, the landforms are a likely product of surface lithological reactions to a regional climate characterised by pronounced multitemporal temperature and moisture shifts, recently and in the past. However, many of the geomorphological processes producing landforms are controlled by microclimates set up by factors such as macro- and microtopography. Conservation implications: The GGHNP is best known for its geological, geomorphological and palaeontological heritage. This paper highlights the diversity of sandstone geomorphological phenomena, many of them rare and ‘unique’ to the region. Not only are these landforms of aesthetic interest to tourists, but they also provide microhabitats for biota. Thus, conservation of biota requires associated conservation of geo-environments where they are established.
Conservation and monitoring of invertebrates in terrestrial protected areas
Authors: McGeoch Melodie A. , Sithole Hendrik , Samways Michael J. , Simaika John P. , Pryke James S. , Picker Mike , Uys Charmaine , Armstrong Adrian J. , Dippenaar-Schoeman Ansie S. , Engelbrecht Ian A. , Braschler Brigitte , Hamer Michelle
Published: May 2011

Invertebrates constitute a substantial proportion of terrestrial and freshwater biodiversity and are critical to ecosystem function. However, their inclusion in biodiversity monitoring and conservation planning and management has lagged behind better-known, more widely appreciated taxa. Significant progress in invertebrate surveys, systematics and bioindication, both globally and locally, means that their use in biodiversity monitoring and conservation is becoming increasingly feasible. Here we outline challenges and solutions to the integration of invertebrates into biodiversity management objectives and monitoring in protected areas in South Africa. We show that such integration is relevant and possible, and assess the relative suitability of seven key taxa in this context. Finally, we outline a series of recommendations for mainstreaming invertebrates in conservation planning, surveys and monitoring in and around protected areas.Conservation implications: Invertebrates constitute a substantial and functionally significant component of terrestrial biodiversity and are valuable indicators of environmental condition. Although consideration of invertebrates has historically been neglected in conservation planning and management, substantial progress with surveys, systematics and bioindication means that it is now both feasible and advisable to incorporate them into protected area monitoring activities.
Taking stock after a decade: Does the ‘thresholds of potential concern’ concept need a socio-ecological revamp?
Authors: Biggs Harry , Ferreira Sam , Freitag-Ronaldson Stefanie , Grant-Biggs Rina
Published: May 2011

The concept of thresholds of potential concern (TPCs) as implemented for the last decade in strategic adaptive management in South African National Parks (SANParks), has proved workable in practice in a number of instances, but in others appears beset by conceptual and practical limitations or barriers. Three common challenges relate to (1) situations where there is uncertainty about whether and where real thresholds exist, (2) whether and how preferences and other social constructs, as opposed to what were seen as objective biophysical variables only, can be used for TPCs and (3) whether it is admissible to adjust TPCs to allow for variations in societal behaviour, in particular rate of management response. All three challenges arise in the face of TPC objectivity implied by the original definition, and in the light of the original view that TPCs be set some distance prior to a presumed ecological threshold. This paper suggests that the three challenges can be partly or largely dealt with by the use of a wider socio-ecological view, rather than seeing TPCs in isolation or as being only biophysical. Also, while detection of abrupt changes is helpful, it makes little practical difference if some TPCs happen to describe linear processes. The very decision to intervene can induce an abrupt change. Once a wider socio-ecological approach is employed, it becomes necessary for the user to specify the particular usage envisaged for the TPC, for instance, whether it is considered a preference and whether that preference is believed in any way to be related to an ecological threshold. In all cases, it is recommended that some form of explicit representation of the socio- ecological view is constructed – we suggest a cause-and-effect diagram (and give an example generated through a thought experiment) which describes presumed relationships in the subsystem of interest. This provides a broader systemic context and a shared understanding, and has implications for considering scenarios and management alternatives. For practical reasons, from the several states and processes in such a subsystem, only a few links can be chosen on which to base particular TPCs. If we have understood the subsystem well enough, these few links, at each of which a TPC is developed, will act as diagnostic points at which we can monitor the performance of the subsystem adequately. A broadened definition of a TPC is presented, supporting this approach.Conservation implications: The concept of thresholds (initially ecological thresholds) has started influencing conservation management practice, a commonly-used formulation for management decision-making being the threshold of potential concern (TPC). Practical TPC usage can often be improved by moving away from its initially pure ecological outlook, rather framing understanding through an interlinked socio-ecological view.
Learning to bridge the gap between adaptive management and organisational culture
Authors: Stirzaker Richard J. , Roux Dirk J. , Biggs Harry C.
Published: May 2011

Adaptive management is the problem-solving approach of choice proposed for complex and multistakeholder environments, which are, at best, only partly predictable. We discuss the implications of this approach as applicable to scientists, who have to overcome certain entrained behaviour patterns in order to participate effectively in an adaptive management process. The challenge does not end there. Scientists and managers soon discover that an adaptive management approach does not only challenge conventional scientific and management behaviour but also clashes with contemporary organisational culture. We explore the shortcomings and requirements of organisations with regard to enabling adaptive management. Our overall conclusion relates to whether organisations are learning-centred or not. Do we continue to filter out unfamiliar information which does not fit our world view and avoid situations where we might fail, or do we use new and challenging situations to reframe the question and prepare ourselves for continued learning? Conservation implications: For an organisation to effectively embrace adaptive management, its mangers and scientists may first have to adapt their own beliefs regarding their respective roles. Instead of seeking certainty for guiding decisions, managers and scientists should acknowledge a degree of uncertainty inherent to complex social and ecological systems and seek to learn from the patterns emerging from every decision and action. The required organisational culture is one of ongoing and purposeful learning with all relevant stakeholders. Such a learning culture is often talked about but rarely practised in the organisational environment.
Systematic conservation planning and adaptive management
Authors: Holness Stephen D. , Biggs Harry C.
Published: May 2011

This article argues that systematic conservation planning (SCP) is an intrinsic part of the adaptive management approach within SANParks and should not be seen as a separate or different initiative. SCP operates within a complex environment that requires a deliberately adaptive approach. The similarities in philosophy, structure and functional elements of the planning process and approach between adaptive management and SCP, as applied within SANParks, are highlighted. The article distils requirements for ensuring that SCP remains strategically adaptive in its approach.Conservation implication: A deliberately adaptive approach to SCP improves its effectiveness in guiding the implementation of conservation actions and is a requirement for effective conservation planning in a complex environment.
History, rationale, and lessons learned: Thresholds of potential concern in Kruger National Park river adaptive management
Authors: McLoughlin Craig A. , Deacon Andrew , Sithole Hendrik , Gyedu-Ababio Thomas
Published: May 2011

The Kruger National Park’s (KNP) adopted system of management, called Strategic Adaptive Management (SAM), originated during the Kruger National Park Rivers Research Programme (KNPRRP) of the 1990s. An important concept in SAM is the thresholds of potential concern (TPCs), representing end-points in a continuum of change. TPCs within the KNP SAM system guide management if or when reached, ‘red-flagging’ possible negative biodiversity impacts and catalysing consideration of management options. TPC-related monitoring generates the strategic information for ongoing evaluation, learning and adaptation within SAM. Post- KNPRRP, although river flow and water quality TPCs have been implemented partly, those designed to detect undesirable changes in biodiversity have not been implemented, until recently. This paper describes the history, rationale, application and ongoing developments associated with the KNP river TPCs over the last decade, providing some key lessons for organisations utilising SAM. The paper concludes with an overview of new thinking and future directions envisaged for the KNP river TPCs, as part of the KNP SAM system. Conservation implications: This paper documents important concepts of strategic adaptive management associated with the KNP river systems. Understanding, related to the rationale and justification for use and development or refinement of the thresholds of potential concern, lays an important foundation for ongoing work in managing these rivers adaptively.
Ticks of four-toed elephant shrews and Southern African hedgehogs
Authors: Horak Ivan G. , Welman Shaun , Hallam Stacey L. , Lutermann Heike , Mzilikazi Nomakwezi
Published: May 2011

Several studies on ticks infesting small mammals, including elephant shrews, have been conducted in South Africa; however, these studies have included only a single four-toed elephant shrew and no hedgehogs. This study thus aimed to identify and quantify the ixodid ticks infesting four-toed elephant shrews and Southern African hedgehogs. Four-toed elephant shrews (Petrodromus tetradactylus) were trapped in dense shrub undergrowth in a nature reserve in north-eastern KwaZulu-Natal. They were separately housed, first in cages and later in glass terraria fitted with wire-mesh bases to allow detached ticks to fall through for collection. Southern African hedgehogs (Atelerix frontalis) were hand caught on a farm in the eastern region of the Northern Cape Province and all visible ticks were collected by means of tweezers while the animals were anaesthetised. The ticks from each animal were preserved separately in 70% ethanol for later identification and counting. The immature stages of five ixodid tick species were collected from the elephant shrews, of which Rhipicephalus muehlensi was the most common. It has not been recorded previously on any species of elephant shrew. Three ixodid tick species were collected from the hedgehogs. Large numbers of adult Haemaphysalis colesbergensis, which has not been encountered previously on hedgehogs, were collected from these animals. Four-toed elephant shrews are good hosts of the larvae and nymphs of R. muehlensi, and Southern African hedgehogs are good hosts of adult H. colesbergensis.
Adapting the Advanced Cardiac Life Support for the Experienced Provider (ACLS-EP) course for emergency care education in Rwanda
Authors: Cayley Jr William E.
Published: May 2011

The Advanced Cardiac Life Support for the Experienced Provider (ACLS-EP) course uses a case-based curriculum to teach emergency resuscitation principles to experienced health care professionals. This article describes the adaptation of the ACLS-EP curriculum to be used in a family medicine training programme in Rwanda, including lessons learned and recommendations for future use of this material for emergency care education in the African setting.
Determinants of patient enablement at primary health care centres in central Ethiopia: a cross-sectional study
Authors: Birhanu Zewdie , Woldie Mirkuzie K. , Assefa Tsion , Morankar Sudhakar
Published: May 2011

Background: Patient enablement is associated with behaviours like treatment adherence and self-care and is becoming a well-accepted indicator of quality of care. However, the concept of patient enablement has never been subjected to scientific inquiry in Ethiopia.Objectives: The aim of this study was to determine the degree of patient enablement and its predictors after consultation at primary health care centres in central Ethiopia.Method: Data were collected from 768 outpatients from six primary health care centres in central Ethiopia during a cross-sectional study designed to assess patient satisfaction.Consecutive patients, 15 years or older, were selected for the study from each health centre.Multinomial logistic regression was performed to identify predictors of patient enablement using SPSS (version 16.0).Results: The study showed that 48.4% of patients expressed an intermediate level of enablement, while 25.4% and 26.2% of the patients expressed low and high levels of patient enablement, respectively. Four models were developed to identify predictors of patient enablement. The first model included socio-demographic variables, showing that residence, educational status and occupational status were significantly associated with patient enablement (p < 0.05). This model explained only 20.5% of the variation. The second and third models included institutional aspects, and perceived doctor–patient interaction and information sharing about illness, respectively. They explained 31.1% and 64.9% of the variation. The fourth model included variables that were significantly associated with patient enablement in the first, second and third models and explained 72% of the variation. In this model, perceived empathy and technical competency, non-verbal communication, familiarity with the provider, information sharing about illness and arrangement for follow-up visits were strong predictors of patient enablement (p < 0.05).Conclusion: The present study revealed specific predictors of patient enablement, which health care providers should consider in their practice to enhance patient enablement after consultation.
Sertindole in the Management of Schizophrenia
Authors: Juruena Mario F. , Ponde00C9; De Sena Eduardo , Reis De Oliveira Irismar
Published: May 2011

Nowadays, new schizophrenia treatments are more ambitious than ever, aiming not only to improve psychotic symptoms, but also quality of life and social reinsertion. Our objective is to briefly but critically review the diagnosis of schizophrenia, the atypical antipsychotics sertindole's pharmacology, safety and status, and mainly evaluate the effects of sertindole compared with other second generation antipsychotics for people with schizophrenia and schizophrenia-like psychosis. In vitro studies showed that sertindole exerts a potent antagonism at serotonin 5-HT2A, 5-HT2C, dopamine D2, and αl adrenergic receptors. Sertindole offers an alternative treatment option for refractory patients given its good EPS profile, favorable metabolic profile, and comparable efficacy to risperidone. Due to cardiovascular safety concerns, sertindole is available as a second-line choice for patients intolerant to other antipsychotic agents. Further clinical studies, mainly comparisons with other second-generation antipsychotic agents, are needed to define the role of sertindole in the treatment of schizophrenia.
A Bott–Borel–Weil Theorem for Diagonal Ind-groups
Authors: Dimitrov Ivan , Penkov Ivan
Published: May 2011

A diagonal ind-group is a direct limit of classical affine algebraic groups of growing rank under a class of inclusions that contains the inclusion

as a typical special case. If G is a diagonal ind-group and B ⊂ G is a Borel ind-subgroup, we consider the ind-variety G/B and compute the cohomology H𝓁(G/B,𝒪−λ) of any G-equivariant line bundle 𝒪−λ on G/B. It has been known that, for a generic λ, all cohomology groups of 𝒪−λ vanish, and that a non-generic equivariant line bundle 𝒪−λ has at most one nonzero cohomology group. The new result of this paper is a precise description of when Hj (G/B,𝒪−λ) is nonzero and the proof of the fact that, whenever nonzero, Hj (G/B,𝒪−λ) is a G-module dual to a highest weight module. The main difficulty is in defining an appropriate analog WB of the Weyl group, so that the action of WB on weights of G is compatible with the analog of the Demazure “action” of the Weyl group on the cohomology of line bundles. The highest weight corresponding to Hj (G/B,𝒪−λ) is then computed by a procedure similar to that in the classical Bott–Borel–Weil theorem.
A new method for continuous measurement of methane and carbon dioxide in surface waters using off‐axis integrated cavity output spectroscopy (ICOS): An example from the Baltic Sea
Authors: Gülzow Wanda , Rehder Gregor , Schneider Bernd , Deimling Jens Schneider v. , Sadkowiak Bernd
Published: May 2011

A new system is presented that allows the continuous measurement of methane and carbon dioxide concentrations in surface waters autonomously using ships of opportunity. The analytical setup consists of a methane carbon dioxide‐Analyzer (MCA, Los Gatos Research) joined to an established equilibrator setup. The analyzer uses off‐axis integrated cavity output spectroscopy (ICOS) and combines a highly specific infrared band laser with a set of strongly reflective mirrors to obtain an effective laser path length of several kilometers. This allows detecting methane and carbon dioxide in the equilibrated gas phase with high precision (less than 0.1%) and frequency. The system was installed on the cargo ship Finnmaid (Finnlines) in November 2009, which commutes regularly in the Baltic Sea between Travemünde (Germany), Gdynia (Poland), and Helsinki (Finland). Methane concentrations of the equilibrated gas phase measured by gas chromatography and by the MCA during lab tests are in excellent agreement. The comparison of carbon dioxide data measured by the MCA system to CO2 values gathered from the same type of equilibrator in combination with a LICOR CO2 detector (Schneider et al. 1992) during onboard operation show concordant results. The time constant for the system in freshwater at room temperature was determined to be 676 s for CH4 and 226 s for CO2. Additional performance tests are presented. First field results show large regional differences with remarkable features, especially in shallow regions, demonstrating the need for the high spatiotemporal data coverage provided by the instrument.
Partitioning stoichiometric components of epilithic biofilm using mixing models
Authors: Small Gaston E. , Bixby Rebecca J. , Kazanci Caner , Pringle Catherine M.
Published: May 2011

Epilithic biofilms are an important and complex food resource in shallow aquatic ecosystems. Standard methods of sampling these biofilms typically yield a combination of algal cells, other organic material, and inorganic sediment. Physical methods of isolating algal fractions rely on differences in density among biofilm components, and clean separation is not always possible. Here, we explore the application of linear mixing models to the problem of estimating nutrient content of biofilm components. This method is based on the assumption that variation in bulk sample elemental composition within a sampling site is due to differences among samples in relative composition. By using standard methods to quantify organic content and algal biomass within biofilm samples, the mixing model produces estimates of nutrient content of each end member. To test this method, we analyzed the phosphorus (P) content of algal cells, non‐algal organic material, and inorganic sediment associated with biofilm samples that increase in P‐content 4‐fold across a natural P gradient in lowland streams in Costa Rica. Our analyses show that nearly all of the observed increase in biofilm P from high‐P streams was due to elevated P‐content of algal cells, rather than P sorbed to inorganic sediments or in Prich heterotrophic bacteria. Results from the mixing model were supported by results from density fractionation. This linear mixing model approach complements empirical methods of separating complex food resources and may lead to a better understanding of trophic interactions in aquatic food webs.
Revised identification of tropical oceanic cumulus congestus as viewed by CloudSat
Authors: Casey S. P. F. , Fetzer E. J. , Kahn B. H.
Published: May 2011

Abstract. Congestus cloud convective features are examined in one year of tropical oceanic cloud observations from the CloudSat/CALIPSO instruments. Two types of convective clouds (cumulus and deep convective, based on classification profiles from radar), and associated differences in radar reflectivity and radar/lidar cloud-top height are considered. Congestus convective features are defined as contiguous convective clouds with heights between 3 and 9 km. A majority of congestus convective features satisfy one of three criteria used in previous studies: (1) CloudSat and CALIPSO cloud-top heights less than 1 km apart; (2) CloudSat 0 dBZ echo-top height less than 1 km from CloudSat cloud-top height, and (3) CloudSat 10 dBZ echo-top height less than 2 km from CloudSat cloud-top height. However, less than half of congestus convective features satisfy all three of these requirements. This implies that previous methods used to identify congestus clouds may be biased towards more vigorous convection, missing more than half of observed congestus and significantly misrepresenting the deduced relationship between congestus clouds and their surroundings.
Evaluating climate model performance with various parameter sets using observations over the recent past
Authors: Loutre M. F. , Mouchet A. , Fichefet T. , Goosse H. , Goelzer H. , Huybrechts P.
Published: May 2011

Abstract. Many sources of uncertainty limit the accuracy of climate projections. Among them, we focus here on the parameter uncertainty, i.e. the imperfect knowledge of the values of many physical parameters in a climate model. Therefore, we use LOVECLIM, a global three-dimensional Earth system model of intermediate complexity and vary several parameters within a range based on the expert judgement of model developers. Nine climatic parameter sets and three carbon cycle parameter sets are selected because they yield present-day climate simulations coherent with observations and they cover a wide range of climate responses to doubled atmospheric CO2 concentration and freshwater flux perturbation in the North Atlantic. Moreover, they also lead to a large range of atmospheric CO2 concentrations in response to prescribed emissions. Consequently, we have at our disposal 27 alternative versions of LOVECLIM (each corresponding to one parameter set) that provide very different responses to some climate forcings. The 27 model versions are then used to illustrate the range of responses provided over the recent past, to compare the time evolution of climate variables over the time interval for which they are available (the last few decades up to more than one century) and to identify the outliers and the "best" versions over that particular time span. For example, between 1979 and 2005, the simulated global annual mean surface temperature increase ranges from 0.24 °C to 0.64 °C, while the simulated increase in atmospheric CO2 concentration varies between 40 and 50 ppmv. Measurements over the same period indicate an increase in global annual mean surface temperature of 0.45 °C (Brohan et al., 2006) and an increase in atmospheric CO2 concentration of 44 ppmv (Enting et al., 1994; GLOBALVIEW-CO2, 2006). Only a few parameter sets yield simulations that reproduce the observed key variables of the climate system over the last decades. Furthermore, our results show that the model response, including its ocean component, is strongly influenced by the model sensitivity to an increase in atmospheric CO2 concentration but much less by its sensitivity to freshwater flux in the North Atlantic. They also highlight weaknesses of the model, in particular its large ocean heat uptake.
Uncertainty in the impacts of projected climate change on the hydrology of a subarctic environment: Liard River Basin
Authors: Thorne R.
Published: May 2011

Abstract. Like many high latitude areas, the mountainous region of subarctic Canada has experienced recent warming and is an area of large inter-annual temperature variations, most notably during the winter. Quantifying how climate tendencies affect streamflow, especially in the spring melt season, is critical not only to regional water resource management, but to understanding the influence of freshwater on the Arctic sea-ice cover and global climate system. The impact of projected atmospheric warming on the discharge of the Liard River is unclear. Here, uncertainty in climate projections associated with GCM structure (2 °C prescribed warming) and magnitude of increases in global mean air temperature (1 to 6 °C) on the river discharge are assessed using a well-tested, semi-distributed hydrological model. Analyses have shown that the hydrological impacts are highly dependant on the GCM scenario. Uncertainties between the GCM scenarios are driven by the inconsistencies in projected spatial variability and magnitude of precipitation, rather than warming temperatures. Despite these uncertainties, the entire scenario simulations project that the subarctic nival regime will be preserved in the future, but the magnitude of change in river discharge is highly uncertain. Generally, spring freshet will arrive earlier, autumn to spring discharge will increase whereas summer flow will decrease, leading to an overall increase in annual discharge.
Active faults crossing trunk pipeline routes: some important steps to avoid disaster
Authors: Besstrashnov V. M. , Strom A. L.
Published: May 2011

Abstract. Assessment of seismic strong motion hazard produced by earthquakes originating within causative fault zones allows rather low accuracy of localisation of these structures that can be provided by indirect evidence of fault activity. In contrast, the relevant accuracy of localisation and characterisation of active faults, capable of surface rupturing, can be achieved solely by the use of direct evidence of fault activity. This differentiation requires strict definition of what can be classified as "active fault" and the normalisation of methods used for identification and localisation of active faults crossing oil and natural gas trunk pipelines.
Diagnostic Value of Clinical Examination and Radiographic Imaging in Identification of Intraocular Foreign Bodies in Open Globe Injury
Authors: Patel Shriji N. , Langer Paul D. , Zarbin Marco A. , Bhagat Neelakshi
Published: May 2011

Purpose

To evaluate the diagnostic accuracy of clinical eye examination and radiographic imaging in the identification of intraocular foreign bodies (IOFBs) in open-globe traumatic injuries.

Methods

This was a retrospective chart review of open-globe traumatic injuries with IOFBs presenting to University Hospital (UH) at New Jersey Medical School between 1998 and 2008.

Results

A total of 527 patients with traumatic open globe injuries presented to UH, Newark, New Jersey, USA, between 1998 and 2008. Of these, 74 patients had surgically confirmed IOFBs. Mean age of patients with traumatic open globe injury and an IOFB was 33 years (range, 8-69 years); mean follow-up was 17.6 months (range, 1 day–90 months). Foreign bodies were identified as glass ( 13 ), metal (58), wood (1), plastic (0), and other (2). There were 24 anterior segment (AS) IOFBs, 45 posterior segment (PS) IOFBs, and 5 noted in both segments. Clinical eye examination at presentation identified an IOFB in 34 (45.6%) of 74 patients. B-scan echography revealed an IOFB in 14 (51.9%) of 27 cases. Computed tomography scan of the orbits identified IOFBs in 56 (94.9%) of 59 cases. Clinical eye examination was performed in all (100%) patients. B-scan was performed only when posterior segment pathology was suspected. Computed tomography scan was performed when an IOFB or orbital fracture was suspected.

Conclusions

Computed tomography scan was the most reliable method for identifying IOFBs in patients presenting with open globe injuries in comparison to clinical eye examination and B-scan echography. This result was consistent regardless of IOFB location within the globe.
Characterization of High‐Strain Rate Mechanical Behavior of AZ31 Magnesium Alloy Using 3D Digital Image Correlation
Authors: Wang Yanli , Xu Hanbing , Erdman Donald L. , Starbuck Michael J. , Simunovic Srdjan
Published: May 2011

Characterization of the material mechanical behavior at sub‐Hopkinson regime (0.1 to 1 000 s−1) is very challenging due to instrumentation limitations and the complexity of data analysis involved in dynamic loading. In this study, AZ31 magnesium alloy sheet specimens are tested using a custom designed servo‐hydraulic machine in tension at nominal strain rates up to 1 000 s−1. In order to resolve strain measurement artifacts, the specimen displacement is measured using 3D Digital Image correlation instead from actuator motion. The total strain is measured up to ≈ 30%, which is far beyond the measurable range of electric resistance strain gages. Stresses are calculated based on the elastic strains in the tab of a standard dog‐bone shaped specimen. Using this technique, the stresses measured for strain rates of 100 s−1 and lower show little or no noise comparing to load cell signals. When the strain rates are higher than 250 s−1, the noises and oscillations in the stress measurements are significantly decreased from ≈ 250 to 50 MPa. Overall, it is found that there are no significant differences in the elongation, although the material exhibits slight work hardening when the strain rate is increased from 1 to 100 s−1.
E‐Field Control of Exchange Bias and Deterministic Magnetization Switching in AFM/FM/FE Multiferroic Heterostructures
Authors: Liu Ming , Lou Jing , Li Shandong , Sun Nian X.
Published: May 2011

The coexistence of electrical polarization and magnetization in multiferroic materials provides great opportunities for novel information storage systems. In particular, magnetoelectric (ME) effect can be realized in multi­ferroic composites consisting of both ferromagnetic and ferroelectric phases through a strain mediated interaction, which offers the possibility of electric field (E‐field) manipulation of magnetic properties or vice versa, and enables novel multiferroic devices such as magnetoelectric random access memories (MERAMs). These MERAMs combine the advantages of FeRAMs (ferroelectric random access memories) and MRAMs (magnetic random access memories), which are non‐volatile magnetic bits switchable by electric field (E‐field). However, it has been challenging to realize 180° deterministic switching of magnetization by E‐field, on which most magnetic memories are based. Here we show E‐field modulating exchange bias and for the first time realization of near 180° dynamic magnetization switching at room temperature in novel AFM (antiferromagnetic)/FM (ferromagnetic)/FE (ferroelectric) multiferroic heterostructures of FeMn/Ni80Fe20/FeGaB/PZN‐PT (lead zinc niobate–lead titanate). Through competition between the E‐field induced uniaxial anisotropy and unidirectional anisotropy, large E‐field‐induced exchange bias field‐shift up to $ {{{\Delta H_{ex}}}\over{{H_{ex}}}} = 218\%$ and near 180° deterministic magnetization switching were demonstrated in the exchange‐coupled multiferroic system of FeMn/Ni80Fe20/FeGaB/PZN‐PT. This E‐field tunable exchange bias and near 180° deterministic magnetization switching at room temperature in AFM/FM/FE multiferroic heterostructures paves a new way for MERAMs and other memory technologies.
Iron Dihydride Complex as the Pre‐catalyst for Efficient Hydrosilylation of Aldehydes and Ketones Under Visible Light Activation
Authors: Castro Luis C. Misal , Bézier David , Sortais Jean‐Baptiste , Darcel Christophe
Published: May 2011

A general and efficient hydrosilylation of aldehydes and ketones into the corresponding alcohols using the well‐defined bis(diphenylphosphinoethane)iron dihydride complex as the pre‐catalyst is reported using polymethylhydrosiloxane (PMHS) as the reducing silylating agent and sodium tetraethoxyborate [NaB(OEt)4] as a co‐catalyst under visible light irradiation. The low catalyst loadings (0.1–1 mol%), the amount of economical hydride source, PMHS and the unconventional way of activation of the pre‐catalyst make this new approach attractive.
Porous Silica Beads Supported TEMPO and Adsorbed NOx (PSB‐TEMPO/NOx): An Efficient Heterogeneous Catalytic System for the Oxidation of Alcohols under Mild Conditions
Authors: Di Lei , Hua Zhang
Published: May 2011

The combination of NOx gas which is stored in the pore canals of porous silica beads (PSB) with a heterogeneous catalyst, PSB‐supported 2,2,6,6‐tetramethylpiperdine 1‐oxyl (PSB‐TEMPO, 1), afforded a highly efficient, widely applicable, and efficiently recyclable approach for the selective aerobic oxidation of alcohols. This novel catalytic system (PSB‐TEMPO/NOx) can be employed in the oxidation of a wide range of alcohols to their corresponding aldehydes and ketones with selectivities as high as 99% at complete conversions under mild conditions. O2 is the terminal oxidant. PSB‐TEMPO can be recycled for more than 10 times without significant loss of activity.
New Polymer‐Supported Catalysts for the Asymmetric Transfer Hydrogenation of Acetophenone in Water – Kinetic and Mechanistic Investigations
Authors: Dimroth Jonas , Schedler Uwe , Keilitz Juliane , Haag Rainer , Schomäcker Reinhard
Published: May 2011

Heterogenization is a powerful approach for the generation of easily recyclable catalysts. In this study, a modified tethered rhodium(III)‐ p‐toluenesulfonyl‐1,2‐diphenylethylenediamine (Rh‐TsDPEN) complex immobilized on polymeric supports was applied to kinetic and up‐scaling experiments on the asymmetric transfer hydrogenation of acetophenone in water. Study of the catalyst has helped in understanding some aspects of its operating mode. The results indicate that, in the investigated range, a simple second‐order model describes the enantioselective conversion of acetophenone to phenylethanol. Optimal reaction conditions were determined, and particularly the solution pH was found to play a decisive role for the activity and reusability of the catalyst. The good performance under optimized conditions emphasizes the practical usefulness of this recyclable catalytic system for environmentally benign asymmetric transfer hydrogenation processes.