Optimization of the Balanced Steady State Free Precession (bSSFP) Pulse Sequence for Magnetic Resonance Imaging of the Mouse Prostate at 3T

INTRODUCTION: MRI can be used to non-invasively monitor tumour growth and response to treatment in mouse models of prostate cancer, particularly for longitudinal studies of orthotopically-implanted models. We have optimized the balanced steady-state free precession (bSSFP) pulse sequence for mouse prostate imaging. METHODS: Phase cycling, excitations, flip angle and receiver bandwidth parameters were optimized for signal to noise ratio and contrast to noise ratio of the prostate. The optimized bSSFP sequence was compared to T1- and T2-weighted spin echo sequences. RESULTS: SNR and CNR increased with flip angle. As bandwidth increased, SNR, CNR and artifacts such as chemical shift decreased. The final optimized sequence was 4 PC, 2 NEX, FA 50°, BW ±62.5 kHz and took 14-26 minutes with 200 µm isotropic resolution. The SNR efficiency of the bSSFP images was higher than for T1WSE and T2WSE. CNR was highest for T1WSE, followed closely by bSSFP, with the T2WSE having the lowest CNR. With the bSSFP images the whole body and organs of interest including renal, iliac, inguinal and popliteal lymph nodes were visible. CONCLUSION: We were able to obtain fast, high-resolution, high CNR images of the healthy mouse prostate with an optimized bSSFP sequence

Mitochondrial Genome Sequences Effectively Reveal the Phylogeny of Hylobates Gibbons

BACKGROUND: Uniquely among hominoids, gibbons exist as multiple geographically contiguous taxa exhibiting distinctive behavioral, morphological, and karyotypic characteristics. However, our understanding of the evolutionary relationships of the various gibbons, especially among Hylobates species, is still limited because previous studies used limited taxon sampling or short mitochondrial DNA (mtDNA) sequences. Here we use mtDNA genome sequences to reconstruct gibbon phylogenetic relationships and reveal the pattern and timing of divergence events in gibbon evolutionary history. METHODOLOGY/PRINCIPAL FINDINGS: We sequenced the mitochondrial genomes of 51 individuals representing 11 species belonging to three genera (Hylobates, Nomascus and Symphalangus) using the high-throughput 454 sequencing system with the parallel tagged sequencing approach. Three phylogenetic analyses (maximum likelihood, Bayesian analysis and neighbor-joining) depicted the gibbon phylogenetic relationships congruently and with strong support values. Most notably, we recover a well-supported phylogeny of the Hylobates gibbons. The estimation of divergence times using Bayesian analysis with relaxed clock model suggests a much more rapid speciation process in Hylobates than in Nomascus. CONCLUSIONS/SIGNIFICANCE: Use of more than 15 kb sequences of the mitochondrial genome provided more informative and robust data than previous studies of short mitochondrial segments (e.g., control region or cytochrome b) as shown by the reliable reconstruction of divergence patterns among Hylobates gibbons. Moreover, molecular dating of the mitogenomic divergence times implied that biogeographic change during the last five million years may be a factor promoting the speciation of Sundaland animals, including Hylobates species

Nuclear versus mitochondrial DNA: evidence for hybridization in colobine monkeys

<p>Abstract</p> <p>Background</p> <p>Colobine monkeys constitute a diverse group of primates with major radiations in Africa and Asia. However, phylogenetic relationships among genera are under debate, and recent molecular studies with incomplete taxon-sampling revealed discordant gene trees. To solve the evolutionary history of colobine genera and to determine causes for possible gene tree incongruences, we combined presence/absence analysis of mobile elements with autosomal, X chromosomal, Y chromosomal and mitochondrial sequence data from all recognized colobine genera.</p> <p>Results</p> <p>Gene tree topologies and divergence age estimates derived from different markers were similar, but differed in placing <it>Piliocolobus/Procolobus </it>and langur genera among colobines. Although insufficient data, homoplasy and incomplete lineage sorting might all have contributed to the discordance among gene trees, hybridization is favored as the main cause of the observed discordance. We propose that African colobines are paraphyletic, but might later have experienced female introgression from <it>Piliocolobus</it>/<it>Procolobus </it>into <it>Colobus</it>. In the late Miocene, colobines invaded Eurasia and diversified into several lineages. Among Asian colobines, <it>Semnopithecus </it>diverged first, indicating langur paraphyly. However, unidirectional gene flow from <it>Semnopithecus </it>into <it>Trachypithecus </it>via male introgression followed by nuclear swamping might have occurred until the earliest Pleistocene.</p> <p>Conclusions</p> <p>Overall, our study provides the most comprehensive view on colobine evolution to date and emphasizes that analyses of various molecular markers, such as mobile elements and sequence data from multiple loci, are crucial to better understand evolutionary relationships and to trace hybridization events. Our results also suggest that sex-specific dispersal patterns, promoted by a respective social organization of the species involved, can result in different hybridization scenarios.</p

Object Grasping of Humanoid Robot Based on YOLO

This paper presents a system that aims to achieve autonomous grasping for micro-controller based humanoid robots such as the Inmoov robot [1]. The system consists of a visual sensor, a central controller and a manipulator. We modify the open sourced objection detection software YOLO (You Only Look Once) v2 [2] and associate it with the visual sensor to make the sensor be able to detect not only the category of the target object but also the location with the help of a depth camera. We also estimate the dimensions (i.e., the height and width) of the target based on the bounding box technique (Fig. 1). After that, we send the information to the central controller (a humanoid robot), which controls the manipulator (customised robotic hand) to grasp the object with the help of inverse kinematics theory. We conduct experiments to test our method with the Inmoov robot. The experiments show that our method is capable of detecting the object and driving the robotic hands to grasp the target object

Witlof Vollstädt/Klaus-Jürgen Tillmann/Udo Rauin/Katrin Hohmann/Andrea Tebrügge: Lehrpläne im Schulalltag. Eine empirische Studie zur Akzeptanz und Wirkung von Lehrplänen in der Sekundarstufe I. Opladen, Leske + Budrich. 1999. [Rezension]

Rezension von: Witlof Vollstädt/Klaus-Jürgen Tillmann/Udo Rauin/Katrin Hohmann/Andrea Tebrügge: Lehrpläne im Schulalltag. Eine empirische Studie zur Akzeptanz und Wirkung von Lehrplänen in der Sekundarstufe I. Opladen, Leske + Budrich. 1999, 231 S

State of the art of the virtual reality applied to design and manufacturing processes

The idea that technology can transfer a person to a different environment without any physical movement and create the illusion of interaction with the artificial environment is not new. Scientists and engineers have been dedicating their efforts to its progressive development over the last fifty years. However, most of the technological advances have been made in the last ten years, undoubtedly thanks to improvements in computer efficiency and the miniaturization of sensorization devices. Nowadays, Virtual Reality is successfully applied in different fields, such as telemedicine, robotics or cinematography. Following on from this success, the question arises of whether we are ready to apply it to industrial design and manufacturing processes. The lack of recent reviews on this technology applied to CAD/CAM, together with its rapid evolution over the last decade, have been the primary motivations for carrying out this study