395 research outputs found
Recolonization of Raoul Island by Kermadec red-crowned parakeets Cyanoramphus novaezelandiae cyanurus after eradication of invasive predators, Kermadec Islands archipelago, New Zealand
The Kermadec red-crowned parakeet Cyanoramphus novaezelandiae was driven to extinction on Raoul Island over 150 years ago by introduced cats Felis catus and rats (Rattus norvegicus and R. exulans). These predators were eradicated from the island (2,938 ha) between 2002-04 during the world’s largest multispecies eradication project. In 2008 we documented a unique recolonisation event when parakeets were observed to have returned to Raoul, presumably from a nearby island group, The Herald Islets (51 ha). We captured and aged 100 parakeets, of which 44% were born in 2008, and breeding was observed on Raoul Island. This represents the first evidence of nesting of this species on Raoul Island since 1836. Our findings highlight the global conservation potential for island avifaunas by prioritising eradication areas through consideration of proximity of remnant populations to target management locations, instead of the classical translocation approach alone. The natural recolonization of parakeets on Raoul Island from a satellite source population is to our knowledge, a first for parrot conservation and the first documented population expansion and island recolonization of a parrot species after removal of invasive predators
Stabilization of carbon nanotubes by filling with inner tubes: An optical spectroscopy study on double-walled carbon nanotubes under hydrostatic pressure
The stabilization of carbon nanotubes via the filling with inner tubes is
demonstrated by probing the optical transitions in double-walled carbon
nanotube bundles under hydrostatic pressure with optical spectroscopy.
Double-walled carbon nanotube films were prepared from fullerene peapods and
characterized by HRTEM and optical spectroscopy. In comparison to single-walled
carbon nanotubes, the pressure-induced redshifts of the optical transitions in
the outer tubes are significantly smaller below 10 GPa, demonstrating the
enhanced mechanical stability due to the inner tube already at low pressures.
Anomalies at the critical pressure P12 GPa signal the onset of the
pressure-induced deformation of the tubular cross-sections. The value of P
is in very good agreement with theoretical predictions of the pressure-induced
structural transitions in double-walled carbon nanotube bundles with similar
average diameters.Comment: 6 pages, 4 figures; to appear in Phys. Rev.
Structure prediction based on ab initio simulated annealing for boron nitride
Possible crystalline modifications of chemical compounds at low temperatures
correspond to local minima of the energy landscape. Determining these minima
via simulated annealing is one method for the prediction of crystal structures,
where the number of atoms per unit cell is the only information used. It is
demonstrated that this method can be applied to covalent systems, at the
example of boron nitride, using ab initio energies in all stages of the
optimization, i.e. both during the global search and the subsequent local
optimization. Ten low lying structure candidates are presented, including both
layered structures and 3d-network structures such as the wurtzite and zinc
blende types, as well as a structure corresponding to the beta-BeO type
Relevanz suszeptibilitätsinduzierter geometrischer Fehlkodierungen für die Validität MR-basierter Knorpelvolumen- und -dickenmessungen im Kniegelenk - Relevance of susceptibility-induced geometrical distortion for the accuracy of MR-based cartilage volume and thickness measurement
The aim of the present study was to analyze the relevance of susceptibility-induced geometrical distortion to the accuracy of MR-based cartilage volume and thickness measurement in the human knee joint. Nine cadaveric knee joints were imaged in the sagittal plane with MRI at a resolution of a x 0.31 x 0.81 mm³, using a fat-suppressed gradient echo sequence, with a normal gradient orientation and also with the frequency- and phase-encoding directions changed. CT arthrographic data sets were then obtained. On the basis of 3-D constructions, we determined the cartilage volume and, with a 3-D minimal distance algorithm, the thickness distribution, of the patella, femur and tibia. Irrespective of the gradient orientation, good agreement was observed between MRI and CT arthrography in terms of cartilage volumes and maximum cartilage thickness. With a normal gradient orientation the volume was overestimated by 2.5 % in MRI, and 2.3 % when the gradients were changed. The maximum cartilage thickness was underestimated by 0.24 intervals (interval = 0.5 mm) with a normal gradient orientation, and by 0.22 intervals when the gradient orientation was changed. In none of the joint surfaces was a relevant difference between the two methods observed. It can be shown that, using high-resolution, fat-suppressed gradient-echo sequences - suseeptibility-induced geometrical distortion has no significant effect on the accuracy of KR-based cartilage volume and thickness measurements. MRI would therefore appear suitable for the design of patient-specific finite element models with the aim of analysing load transmission in diarthrodial joints and planning surgical interventions
Simulating ice thickness and velocity evolution of Upernavik Isstrom 1849-2012 by forcing prescribed terminus positions in ISSM
Abstract. Tidewater glacier velocity and mass balance are known to be
highly responsive to terminus position change. Yet it remains challenging
for ice flow models to reproduce observed ice margin changes. Here, using the
Ice Sheet System Model (Larour et al., 2012), we simulate the ice velocity
and thickness changes of Upernavik Isstrøm (north-western Greenland) by prescribing
a collection of 27 observed terminus positions spanning 164 years
(1849–2012). The simulation shows increased ice velocity during the 1930s,
the late 1970s and between 1995 and 2012 when terminus retreat was observed
along with negative surface mass balance anomalies. Three distinct mass
balance states are evident in the reconstruction: (1849–1932) with near zero
mass balance, (1932–1992) with ice mass loss dominated by ice dynamical
flow, and (1998–2012), when increased retreat and negative surface mass
balance anomalies led to mass loss that was twice that of any earlier period. Over
the multi-decadal simulation, mass loss was dominated by thinning and
acceleration responsible for 70 % of the total mass loss induced by
prescribed change in terminus position. The remaining 30 % of the
total ice mass loss resulted directly from prescribed terminus retreat and
decreasing surface mass balance. Although the method can not explain the
cause of glacier retreat, it enables the reconstruction of ice flow and
geometry during 1849–2012. Given annual or seasonal observed terminus front
positions, this method could be a useful tool for evaluating simulations
investigating the effect of calving laws.
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Functionally Conserved Noncoding Regulators of Cardiomyocyte Proliferation and Regeneration in Mouse and Human
BACKGROUND: The adult mammalian heart has little regenerative
capacity after myocardial infarction (MI), whereas neonatal mouse heart
regenerates without scarring or dysfunction. However, the underlying
pathways are poorly defined. We sought to derive insights into the
pathways regulating neonatal development of the mouse heart and
cardiac regeneration post-MI.
METHODS AND RESULTS: Total RNA-seq of mouse heart through
the first 10 days of postnatal life (referred to as P3, P5, P10) revealed
a previously unobserved transition in microRNA (miRNA) expression
between P3 and P5 associated specifically with altered expression of
protein-coding genes on the focal adhesion pathway and cessation
of cardiomyocyte cell division. We found profound changes in the
coding and noncoding transcriptome after neonatal MI, with evidence
of essentially complete healing by P10. Over two-thirds of each
of the messenger RNAs, long noncoding RNAs, and miRNAs that
were differentially expressed in the post-MI heart were differentially
expressed during normal postnatal development, suggesting a common
regulatory pathway for normal cardiac development and post-MI cardiac
regeneration. We selected exemplars of miRNAs implicated in our data
set as regulators of cardiomyocyte proliferation. Several of these showed
evidence of a functional influence on mouse cardiomyocyte cell division.
In addition, a subset of these miRNAs, miR-144-3p, miR-195a-5p, miR-
451a, and miR-6240 showed evidence of functional conservation in
human cardiomyocytes.
CONCLUSIONS: The sets of messenger RNAs, miRNAs, and long
noncoding RNAs that we report here merit further investigation as
gatekeepers of cell division in the postnatal heart and as targets for
extension of the period of cardiac regeneration beyond the neonatal
period.Leducq Foundation funding via the Transatlantic Network of Excellence (Grant 11CVD01), the British Heart Foundation funding via the Imperial College Centre of Research Excellence and the Imperial Cardiovascular Regenerative Medicine Centre RM/13/1/30157
Benralizumab Reduces Respiratory Exacerbations and Oral Glucocorticosteroid Dose in Patients with Severe Asthma and Eosinophilic Granulomatosis with Polyangiitis
Carlo Mümmler,1 Pontus Mertsch,1 Michaela Barnikel,1 Frank Haubner,2 Ulf Schönermarck,3 Ulrich Grabmaier,4 Hendrik Schulze-Koops,5 Jürgen Behr,1 Nikolaus Kneidinger,1,6 Katrin Milger1 1Department of Medicine V, LMU University Hospital, LMU Munich, Comprehensive Pneumology Center, Member of the German Center of Lung Research (DZL), Munich, Germany; 2Department of Otorhinolaryngology, LMU University Hospital, LMU Munich, Munich, Germany; 3Division of Nephrology, Department of Medicine IV, LMU University Hospital, LMU Munich, Munich, Germany; 4Department of Medicine I, LMU University Hospital, LMU Munich, Munich, Germany; 5Division of Rheumatology and Clinical Immunology, Department of Medicine IV, LMU University Hospital, LMU Munich, Munich, Germany; 6Division of Pulmonology, Department of Internal Medicine, Medical University of Graz, Graz, AustriaCorrespondence: Katrin Milger, Department of Medicine V, LMU University Hospital, Marchioninistr, 15, LMU Munich, Munich, 81377, Germany, Tel +49-89-4400-73071, Email [email protected]: Benralizumab reduces exacerbations and long-term oral glucocorticosteroid (OCS) exposure in patients with severe eosinophilic asthma. In patients with eosinophilic granulomatosis with polyangiitis (EGPA), uncontrolled symptoms and exacerbations of asthma and chronic rhinosinusitis (CRS) are important reasons for continued OCS therapies. We aimed to describe outcomes of patients with severe asthma and EGPA treated with benralizumab in real-life.Methods: We retrospectively analyzed adult patients from the Severe Asthma Unit at LMU Munich diagnosed with severe asthma and EGPA treated with benralizumab, differentiating two groups: Group A, patients with a stable daily OCS dose and diagnosis of EGPA > 6 months ago; and Group B, patients treated with high-dose daily OCS due to recent diagnosis of EGPA < 6 months ago. We compared outcome parameters at baseline and 12 months after initiation of benralizumab, including respiratory exacerbations, daily OCS dose, and lung function.Results: Group A included 17 patients, all receiving OCS therapy and additional immunosuppressants; 15 patients (88%) continued benralizumab for more than 12 months, demonstrating a significant reduction in daily OCS dose and exacerbations while FEV1 increased. Group B included 9 patients, all with high-dose daily OCS and some receiving cyclophosphamide pulse therapy for life-threatening disease. Benralizumab addition during induction was well tolerated. A total of 7/9 (78%) continued benralizumab for more than 12 months and preserved EGPA remission at the 12-month timepoint.Conclusion: In this real-life cohort of patients with severe asthma and EGPA, benralizumab initiation during remission maintenance reduced respiratory exacerbations and daily OCS dose. Benralizumab initiation during remission induction was associated with a high rate of clinical EGPA remission.Keywords: EGPA, asthma, CRS, vasculitis, glucocorticoid, OCS, anti-IL5R, biologics, benralizuma
Synthesis and Investigation of a Radioiodinated F3 Peptide Analog as a SPECT Tumor Imaging Radioligand
A radioiodinated derivative of the tumor-homing F3 peptide, (N-(2-{3-[125I]Iodobenzoyl}aminoethyl)maleimide-F3Cys peptide, [125I]IBMF3 was developed for investigation as a SPECT tumor imaging radioligand. For this purpose, we custom synthesized a modified F3 peptide analog (F3Cys) incorporating a C-terminal cysteine residue for site-specific attachment of a radioiodinated maleimide conjugating group. Initial proof-of-concept Fluorescence studies conducted with AlexaFluor 532 C5 maleimide-labeled F3Cys showed distinct membrane and nuclear localization of F3Cys in MDA-MB-435 cells. Additionally, F3Cys conjugated with NIR fluorochrome AlexaFluor 647 C2 maleimide demonstrated high tumor specific uptake in melanoma cancer MDA-MB-435 and lung cancer A549 xenografts in nude mice whereas a similarly labeled control peptide did not show any tumor uptake. These results were also confirmed by ex vivo tissue analysis. No-carrier-added [125I]IBMF3 was synthesized by a radioiododestannylation approach in 73% overall radiochemical yield. In vitro cell uptake studies conducted with [125I]IBMF3 displayed a 5-fold increase in its cell uptake at 4 h when compared to controls. SPECT imaging studies with [125I]IBMF3 in tumor bearing nude mice showed clear visualization of MDA-MB-435 xenografts on systemic administration. These studies demonstrate a potential utility of F3 peptide-based radioligands for tumor imaging with PET or SPECT techniques
Paramagnetic and fluorescent liposomes for target-specific imaging and therapy of tumor angiogenesis
Angiogenesis is essential for tumor growth and metastatic potential and for that reason considered an important target for tumor treatment. Noninvasive imaging technologies, capable of visualizing tumor angiogenesis and evaluating the efficacy of angiostatic therapies, are therefore becoming increasingly important. Among the various imaging modalities, magnetic resonance imaging (MRI) is characterized by a superb spatial resolution and anatomical soft-tissue contrast. Revolutionary advances in contrast agent chemistry have delivered versatile angiogenesis-specific molecular MRI contrast agents. In this paper, we review recent advances in the preclinical application of paramagnetic and fluorescent liposomes for noninvasive visualization of the molecular processes involved in tumor angiogenesis. This liposomal contrast agent platform can be prepared with a high payload of contrast generating material, thereby facilitating its detection, and is equipped with one or more types of targeting ligands for binding to specific molecules expressed at the angiogenic site. Multimodal liposomes endowed with contrast material for complementary imaging technologies, e.g., MRI and optical, can be exploited to gain important preclinical insights into the mechanisms of binding and accumulation at angiogenic vascular endothelium and to corroborate the in vivo findings. Interestingly, liposomes can be designed to contain angiostatic therapeutics, allowing for image-supervised drug delivery and subsequent monitoring of therapeutic efficacy
PI3Kγ Protects from Myocardial Ischemia and Reperfusion Injury through a Kinase-Independent Pathway
BACKGROUND: PI3Kgamma functions in the immune compartment to promote inflammation in response to G-protein-coupled receptor (GPCR) agonists and PI3Kgamma also acts within the heart itself both as a negative regulator of cardiac contractility and as a pro-survival factor. Thus, PI3Kgamma has the potential to both promote and limit M I/R injury. METHODOLOGY/PRINCIPAL FINDINGS: Complete PI3Kgamma-/- mutant mice, catalytically inactive PI3KgammaKD/KD (KD) knock-in mice, and control wild type (WT) mice were subjected to in vivo myocardial ischemia and reperfusion (M I/R) injury. Additionally, bone-marrow chimeric mice were constructed to elucidate the contribution of the inflammatory response to cardiac damage. PI3Kgamma-/- mice exhibited a significantly increased infarction size following reperfusion. Mechanistically, PI3Kgamma is required for activation of the Reperfusion Injury Salvage Kinase (RISK) pathway (AKT/ERK1/2) and regulates phospholamban phosphorylation in the acute injury response. Using bone marrow chimeras, the cardioprotective role of PI3Kgamma was mapped to non-haematopoietic cells. Importantly, this massive increase in M I/R injury in PI3Kgamma-/- mice was rescued in PI3Kgamma kinase-dead (PI3KgammaKD/KD) knock-in mice. However, PI3KgammaKD/KD mice exhibited a cardiac injury similar to wild type animals, suggesting that specific blockade of PI3Kgamma catalytic activity has no beneficial effects. CONCLUSIONS/SIGNIFICANCE: Our data show that PI3Kgamma is cardioprotective during M I/R injury independent of its catalytic kinase activity and that loss of PI3Kgamma function in the hematopoietic compartment does not affect disease outcome. Thus, clinical development of specific PI3Kgamma blockers should proceed with caution
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