Taxonomy of the Crematogaster degeeri-species-assemblage in the Malagasy region (Hymenoptera: Formicidae)

We revise the species-level taxonomy of the Crematogaster (Crematogaster) degeerispecies-assemblage, a group of related ants occuring in Madagascar and the wider Malagasy region, and further provide an identification key to all species-groups of the genus Crematogaster in this region. Within the C. degeeri-assemblage, we recognize twelve species based upon morphological data from worker, queen and male ants, as well as genetic data from the barcode region of cytochrome oxidase I. Seven new species are described: Crematogaster alafara Blaimer sp. nov., C. bara Blaimer sp. nov., C. mafybe Blaimer sp. nov., C.maina Blaimer sp. nov., C. malahelo Blaimer sp. nov., C. masokely Blaimer sp. nov., C. ramamy Blaimer sp. nov. Crematogaster tricolor Gerstäcker, 1859 (stat. rev.) and C. dentata Dalla Torre, 1893 (stat. nov.) are raised to species level, and the following new synonymies are proposed: Crematogaster degeeri lunaris Santschi, 1928 as a synonym of C. degeeri Forel, 1886; Crematogaster sewelli improba Forel, 1907 and C. sewelli mauritiana Forel, 1907 as synonyms of C. dentata Dalla Torre, 1893, and C. pacifi ca Santschi, 1919 as a synonym of C. lobata Emery, 1895. Species descriptions, images, and distribution maps and identification keys based on worker ants, as well as on queen ants where available, are presented for all twelve species. In addition, we present a molecular gene tree for cytochrome oxidase I and summarize levels of sequence divergence within and between species of the C. degeeri-species-assemblage. Our findings are discussed in the light of previous work on Malagasy Crematogaster ants

Optimal Domain and Integral Extension of Operators Acting in Frechet Function Spaces

It is known that a continuous linear operator T defined on a Banach function space X(μ) (over a finite measure space (Ω,Σ,μ)) and with values in a Banach space X can be extended to a sort of optimal domain. Indeed, under certain assumptions on the space X(μ) and the operator T this optimal domain coincides with L1(mT), the space of all functions integrable with respect to the vector measure mT associated with T, and the optimal extension of T turns out to be the integration operator ImT. In this book the idea is taken up and the corresponding theory is translated to a larger class of function spaces, namely to Fr\'echet function spaces X(μ) (this time over a σ-finite measure space (Ω,Σ,μ). It is shown that under similar assumptions on X(μ) and T as in the case of Banach function spaces the so-called ``optimal extension process'' also works for this altered situation. In a further step the newly gained results are applied to four well-known operators defined on the Fréchet function spaces Lp-([0,1]) resp. Lp-(G) (where G is a compact Abelian group) and Lploc

Impact of innate and adaptive immune cells in tumor immune surveillance

Krebs ist eine der führenden Todesursachen weltweit. Im Jahr 2018 verzeichnete die Internationale Agentur für Krebsforschung (IARC) 18,1 Millionen neue Krebsfälle und eine Sterblichkeitsrate von 9,6 Millionen Krebstodesfällen mit steigender Inzidenz. Für 2040 wird ein Anstieg von 61,7% gegenüber 2018 erwartet. Die Behandlung von Krebs hängt von der Art und des Stadiums ab. Die Behandlungsmodalitäten reichen von Operation, Strahlentherapie, Chemotherapie und Hormontherapie bis hin zur gezielten Therapie, die entweder als Einzelbehandlung oder in Kombinationtherapien eingesetzt werden können. In den letzten Jahren hat sich die Immuntherapie als sehr vielversprechend bei der Behandlung oder Heilung von Krebs erwiesen, Immunzellen können Gewebe erreichen, wo Operationen unmöglich sind, und sogar mikroskopische Krankheiten oder Metastasen behandeln. Es gibt verschiedene Arten von Immuntherapien, darunter solche, die tumorspezifische Immunzellen ("Zelltherapie") einsetzen, um Krebszellen anzugreifen, oder solche, die bereits bestehende tumorspezifische Immunantworten im Körper verstärken. In meiner Dissertation wurden zwei verschiedene Tumormausmodelle, die die natürliche Tumorentwicklung nachahmen, verwendet, um die Rolle des angeborenen und adaptiven Immunsystem, wie bespielsweise NK-Zellen und CD8+ T-Zellen, bei der natürlichen Immunüberwachung von Tumoren zu untersuchen. Wir beobachteten, dass die Tumorentwicklung bei Mäusen im Allgemeinen zu einer Stimulation der Differenzierung und Aktivität von NK-Zellen führte. Eine anhaltende Stimulation von NK-Zellen durch Tumorzellen führte jedoch zur Bildung von terminal-differenzierten CD27low-NK-Zellen mit verminderter Antitumorkapazität. Während die IL-15-Behandlung von Mäusen die Entwicklung dieser spezifischen Untergruppe von Immunzellen förderte, führte sie außerdem zur Erschöpfung der NK-Zellen. Im Gegenzug veränderte die Tumorentwicklung die Verteilung der CD8+ T-Zelluntergruppen nicht, und naive CD8+ T-Zellen waren im Laufe der Tumorentwicklung die dominierende Subpopulation. Erst die Behandlung von Mäusen mit IL-15 führte zu einer Akkumulation von terminal-differenzierten T-Zellen, die sich auch durch eine geringe Zytotoxizität und eine reduzierte Zytokinproduktion auszeichneten. Zusammengenommen sind Tumorzellen, die sich natürlicherweise in einem Spontankrebsmodell entwickeln, in der Lage, der Zerstörung durch das Immunsystem zu entgehen, indem sie die Bildung von Immunzellen mit geringer Anti-Tumor-Aktivität fördern. Die Behandlung von Mäusen mit IL-15 stärkt kurzzeitig das Immunsystem, aber die Anhäufung von terminal-differenzierten Immunzellen mit einem erschöpften Phänotyp führt zur endgültigen Ineffizienz dieser Zytokinbehandlung und zur unkontrollierten Entwicklung von Tumoren und Metastasen

Utilización de los diagramas de Minkowski para la enseñanza de la Teoría Especial de la Relatividad en la escuela secundaria

En este trabajo se presentan los resultados de la implementación de una etapa de una Secuencia de Enseñanza y Aprendizaje diseñada para abordar la Teoría Especial de la Relatividad en la escuela secundaria superior, en Argentina. Se adopta el modelo de Enseñanza para la Comprensión dentro de un marco teórico más amplio que promueve un aprendizaje significativo de la Teoría Especial de la Relatividad.El objetivo de esta investigación es analizar si la utilización de los diagramas de Minkowski, para establecer la simultaneidad de eventos en la Teoría Especial de la Relatividad, es una herramienta apropiada para la escuela secundaria.La metodología empleada en la investigación es cualitativa de tipo descriptiva. La implementación se realizó en dos cursos de secundaria superior de una escuela pública dependiente de la Universidad Nacional del Centro, conformados por 65 alumnos. Los resultados obtenidos evidencian rasgos de aprendizaje significativo de la Teoría Especial de la Relatividad, por parte de los alumnos.In this paper the results of the implementation of a step in a Teaching - Learning sequence designed to approach the Special Relativity Theory in high school in Argentina are presented. The purpose of this research is to analyze whether the use of Minkowski diagrams to establish the simultaneity of events in the Special Relativity Theory is an appropriate tool for high school. The methodology used in this research is qualitative and descriptive. The implementation was done in two courses of a public high school that is dependent of the Universidad Nacional del Centro (Argentina), with 65 students. The results show that students achieved meaningful learning in some topics of Special Relativity Theory.Fil: Cayul, Esther. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Grupo Educación en Ciencias con Tecnologías; ArgentinaFil: Arriassecq, Irene. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Grupo Educación en Ciencias con Tecnologías; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Imprecision and DNA break repair biased towards incompatible end joining in leukemia

Cancer is a genetic disease caused by mutations and chromosomal abnormalities that contribute to uncontrolled cell growth. In addition, cancer cells can rapidly respond to conventional and targeted therapies by accumulating novel and often specific genetic lesions leading to acquired drug resistance and relapsing disease. In chronic lymphocytic leukemia (CLL), however, diverse chromosomal aberrations often occur. In many cases, improper repair of DNA double-strand breaks (DSB) is a major source for genomic abnormalities. Therefore, this study examined the repair of DNA DSBs by nonhomologous end joining (NHEJ) in CLL by performing plasmid-based repair assays in primary CLL cells and normal B cells, isolated from patients, as well as TALEN/Cas9–induced chromosomal deletions in the CLL cell line Mec1. It is demonstrated that DNA repair is aberrant in CLL cells, featuring perturbed DNA break structure preference with efficient joining of noncohesive ends and more deletions at repair junctions. In addition, increased microhomology-mediated end joining (MMEJ) of DNA substrates was observed in CLL together with increased expression of MMEJ-specific repair factors. In summary, these data identify major differences in DNA repair efficiency between CLL cells and normal B cells isolated from patients

Simultaneous Multislice (SMS) Imaging Techniques

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Controlling the object phase for g factor reduction in phase-constrained parallel MRI using spatially selective RF pulses

Parallel imaging generally entails a reduction in the signal-to-noise ratio (SNR) of the final image. Phase-constrained methods aim to improve reconstruction quality by employing symmetry properties of k space. Noise amplification in phase-constrained reconstruction heavily depends on the object background phase. The purpose of this work is to present a new approach of using tailored RF pulses to optimize the object phase distribution in order to maximize the benefit of phase-constrained reconstruction, and minimize the noise amplification. Intrinsic object phase and coil sensitivity profiles are measured in a prescan. Optimal phase distribution is computed to maximize SNR in the given setup. Tailored RF pulses are designed to introduce the optimal phase map in the following accelerated acquisitions, subsequently reconstructed by phase-constrained methods. The potential of the method is demonstrated in vivo with in-plane accelerated (8x) and simultaneous multi-slice (3x) acquisitions. Mean g-factors are reduced by up to a factor of 2 compared to conventional techniques when an appropriate phase-constrained reconstruction is applied to phase-optimized acquisitions, enhancing the SNR of the final images and the visibility of small details. Combining phase-constrained reconstruction and phase optimization by tailored RF pulses can provide notable improvement in the SNR and reconstruction quality of accelerated MRI

Accelerated Cardiac Magnetic Resonance Imaging in the Mouse Using an Eight-Channel Array at 9.4 Tesla

MRI has become an important tool to noninvasively assess global and regional cardiac function, infarct size, or myocardial blood flow in surgically or genetically modified mouse models of human heart disease. Constraints on scan time due to sensitivity to general anesthesia in hemodynamically compromised mice frequently limit the number of parameters available in one imaging session. Parallel imaging techniques to reduce acquisition times require coil arrays, which are technically challenging to design at ultrahigh magnetic field strengths. This work validates the use of an eight-channel volume phased-array coil for cardiac MRI in mice at 9.4 T. Two- and three-dimensional sequences were combined with parallel imaging techniques and used to quantify global cardiac function, T1-relaxation times and infarct sizes. Furthermore, the rapid acquisition of functional cine-data allowed for the first time in mice measurement of left-ventricular peak filling and ejection rates under intravenous infusion of dobutamine. The results demonstrate that a threefold accelerated data acquisition is generally feasible without compromising the accuracy of the results. This strategy may eventually pave the way for routine, multiparametric phenotyping of mouse hearts in vivo within one imaging session of tolerable duration. Magn Reson Med, 2010. © 2010 Wiley-Liss, Inc

Feasibility of in vivo measurement of carotid wall shear rate using spiral Fourier velocity encoded MRI

Arterial wall shear stress is widely believed to influence the formation and growth of atherosclerotic plaque; however, there is currently no gold standard for its in vivo measurement. The use of phase contrast MRI has proved to be challenging due to partial-volume effects and inadequate signal-to-noise ratio at the high spatial resolutions that are required. This work evaluates the use of spiral Fourier velocity encoded MRI as a rapid method for assessing wall shear rate in the carotid arteries. Wall shear rate is calculated from velocity histograms in voxels spanning the blood/vessel wall interface, using a method developed by Frayne and Rutt (Magn Reson Med 1995;34:378–387). This study (i) demonstrates the accuracy of the velocity histograms measured by spiral Fourier velocity encoding in a pulsatile carotid flow phantom compared with high-resolution two-dimensional Fourier transform phase contrast, (ii) demonstrates the accuracy of Fourier velocity encoding–based shear rate measurements in a numerical phantom designed using a computational fluid dynamics simulation of carotid flow, and (iii) demonstrates in vivo measurement of regional wall shear rate and oscillatory shear index in the carotid arteries of healthy volunteers at 3 T. Magn Reson Med 63:1537–1547, 2010. © 2010 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75777/1/22325_ftp.pd