1,268 research outputs found
Effects of alpha-Calcitonin Gene-related Peptide on Osteoprotegerin and Receptor Activator of Nuclear Factor-kappaB Ligand Expression in MG-63 Osteoblast-like Cells exposed to Polyethylene Particles
BACKGROUND: Recent studies demonstrated an impact of the nervous system on particle-induced osteolysis, the major cause of aseptic loosening of joint replacements. METHODS: In this study of MG-63 osteoblast-like cells we analyzed the influence of ultra-high molecular weight polyethylene (UHMWPE) particles and the neurotransmitter alpha-calcitonin gene-related peptide (CGRP) on the osteoprotegerin/receptor activator of nuclear factor-κB ligand/receptor activator of nuclear factorκB (OPG/RANKL/RANK) system. MG-63 cells were stimulated by different UHMWPE particle concentrations (1:100, 1:500) and different doses of alpha-CGRP (10(-7 )M, 10(-9 )M, 10(-11 )M). RANKL and OPG mRNA expression and protein levels were measured by RT-PCR and Western blot. RESULTS: Increasing particle concentrations caused an up-regulation of RANKL after 72 hours. Alpha-CGRP showed a dose-independent depressive effect on particle-induced expression of RANKL mRNA in both cell-particle ratios. RANKL gene transcripts were significantly (P < 0.05) decreased by alpha-CGRP treatment after 48 and 72 hours. OPG mRNA was significantly down-regulated in a cell-particle ratio of 1:500 after 72 hours. Alpha-CGRP concentrations of 10(-7 )M lead to an up-regulation of OPG protein. CONCLUSION: In conclusion, a possible osteoprotective influence of the neurotransmitter alpha-CGRP on particle stimulated osteoblast-like cells could be shown. Alpha-CGRP might be important for bone metabolism under conditions of particle-induced osteolysis
Activated partial thromboplastin time waveform analysis as specific sepsis marker in cardiopulmonary bypass surgery
Throughout the last years, several new diagnostic biomarkers have been introduced into clinical routine to identify a systemic inflammatory response syndrome (SIRS) or a septic state and to discriminate between these two entities. According to studies in selected patients, measurement of these biomarkers may be advantageous under certain clinical conditions. On an individual basis, however, these sepsis markers usually lack an adequate negative or positive predictive power. Therefore, physicians in charge still have to rely on a combination of personal experience and results from clinical or laboratory tests when deciding on a patient's therapy. For surgical patients, a key problem consists of the time delay which is associated with the diagnosis of serious postoperative infections and which may negatively affect outcome. It is in this context where the activated partial thromboplastin time waveform analysis may represent a promising new method to discriminate between SIRS and sepsis, thereby shortening the time to therapy. Nevertheless, studies involving large patient populations will be necessary to prove the efficacy of this new diagnostic concept either as a single tool or in combination with the measurement of other biomarkers
The Hypocrea jecorina (Trichoderma reesei) hypercellulolytic mutant RUT C30 lacks a 85 kb (29 gene-encoding) region of the wild-type genome
<p>Abstract</p> <p>Background</p> <p>The hypercellulolytic mutant <it>Hypocrea jecorina </it>(anamorph <it>Trichoderma reesei</it>) RUT C30 is the <it>H. jecorina </it>strain most frequently used for cellulase fermentations and has also often been employed for basic research on cellulase regulation. This strain has been reported to contain a truncated carbon catabolite repressor gene <it>cre1 </it>and is consequently carbon catabolite derepressed. To date this and an additional frame-shift mutation in the glycoprotein-processing β-glucosidase II encoding gene are the only known genetic differences in strain RUT C30.</p> <p>Results</p> <p>In the present paper we show that <it>H. jecorina </it>RUT C30 lacks an 85 kb genomic fragment, and consequently misses additional 29 genes comprising transcription factors, enzymes of the primary metabolism and transport proteins. This loss is already present in the ancestor of RUT C30 – NG 14 – and seems to have occurred in a palindromic AT-rich repeat (PATRR) typically inducing chromosomal translocations, and is not linked to the <it>cre1 </it>locus. The mutation of the <it>cre1 </it>locus has specifically occurred in RUT C30. Some of the genes that are lacking in RUT C30 could be correlated with pronounced alterations in its phenotype, such as poor growth on α-linked oligo- and polyglucosides (loss of maltose permease), or disturbance of osmotic homeostasis.</p> <p>Conclusion</p> <p>Our data place a general caveat on the use of <it>H. jecorina </it>RUT C30 for further basic research.</p
Sampling-Based Trajectory (re)planning for Differentially Flat Systems: Application to a 3D Gantry Crane
In this paper, a sampling-based trajectory planning algorithm for a
laboratory-scale 3D gantry crane in an environment with static obstacles and
subject to bounds on the velocity and acceleration of the gantry crane system
is presented. The focus is on developing a fast motion planning algorithm for
differentially flat systems, where intermediate results can be stored and
reused for further tasks, such as replanning. The proposed approach is based on
the informed optimal rapidly exploring random tree algorithm (informed RRT*),
which is utilized to build trajectory trees that are reused for replanning when
the start and/or target states change. In contrast to state-of-the-art
approaches, the proposed motion planning algorithm incorporates a linear
quadratic minimum time (LQTM) local planner. Thus, dynamic properties such as
time optimality and the smoothness of the trajectory are directly considered in
the proposed algorithm. Moreover, by integrating the branch-and-bound method to
perform the pruning process on the trajectory tree, the proposed algorithm can
eliminate points in the tree that do not contribute to finding better
solutions. This helps to curb memory consumption and reduce the computational
complexity during motion (re)planning. Simulation results for a validated
mathematical model of a 3D gantry crane show the feasibility of the proposed
approach.Comment: Published at IFAC-PapersOnLine (13th IFAC Symposium on Robot Control
Singularity Avoidance with Application to Online Trajectory Optimization for Serial Manipulators
This work proposes a novel singularity avoidance approach for real-time
trajectory optimization based on known singular configurations. The focus of
this work lies on analyzing kinematically singular configurations for three
robots with different kinematic structures, i.e., the Comau Racer 7-1.4, the
KUKA LBR iiwa R820, and the Franka Emika Panda, and exploiting these
configurations in form of tailored potential functions for singularity
avoidance. Monte Carlo simulations of the proposed method and the commonly used
manipulability maximization approach are performed for comparison. The
numerical results show that the average computing time can be reduced and
shorter trajectories in both time and path length are obtained with the
proposed approachComment: 8 pages, 2 figures, Accepted for publication at IFAC World Congress
202
Acute and long-term survival in chronically critically ill surgical patients: a retrospective observational study
Introduction Various cohort studies have shown that acute ( short-term) mortality rates in unselected critically ill patients may have improved during the past 15 years. Whether these benefits also affect acute and long-term prognosis in chronically critically ill patients is unclear, as are determinants relevant to prognosis. Methods We conducted a retrospective analysis of data collected from March 1993 to February 2005. A cohort of 390 consecutive surgical patients requiring intensive care therapy for more than 28 days was analyzed. Results The intensive care unit ( ICU) survival rate was 53.6%. Survival rates at one, three and five years were 61.8%, 44.7% and 37.0% among ICU survivors. After adjustment for relevant covariates, acute and long-term survival rates did not differ significantly between 1993 to 1999 and 1999 to 2005 intervals. Acute prognosis was determined by disease severity during ICU stay and by primary diagnosis. However, only the latter was independently associated with long-term prognosis. Advanced age was an independent prognostic determinant of poor short-term and long-term survival. Conclusion Acute and long-term prognosis in chronically critically ill surgical patients has remained unchanged throughout the past 12 years. After successful surgical intervention and intensive care, long-term outcome is reasonably good and is mainly determined by age and underlying disease
The monumental landscape transformation of the Island of Babeldaob (Republic of Palau)
Babeldaob is the largest island of Palau. The landscape of this mostly volcanic island is dominated by monumental earthworks, like terraced hills, crown and moat constructions, and modified ridgelines. The majority of the Palau earthworks were built between 2400 and 1200 BP, making them the oldest examples of monumentality in Oceania according to the current state of research. Despite the degree of landscape transformation on Babeldaob, the monumental aspect of the earthworks, and the fact that oral traditions are of utmost importance in the Palauan society, little information about the construction, the function, and significance of them has been passed down. Notwithstanding several archaeological investigations in the last years, questions about the chronology, genesis, function, and use of the earthworks are still open. Did the terraces serve as settlement areas? Have they been used for horticulture? Did they have a ritual or political significance? Or were they used for defence? Using aerial photogrammetry, we generated 3D-models of 14 earthworks that served as a basis for placing test trenches to investigate the construction methods and function of the monuments. Detailed geoarchaeological, geomorphological, pedological, and sedimentological analysis showed many aspects of building techniques, ancient land use, and the high stability of the earthworks
Protein quality control during aging involves recruitment of the macroautophagy pathway by BAG3
The Hsc/Hsp70 co-chaperones of the BAG (Bcl-2-associated athanogene) protein family are modulators of protein quality control. We examined the specific roles of BAG1 and BAG3 in protein degradation during the aging process. We show that BAG1 and BAG3 regulate proteasomal and macroautophagic pathways, respectively, for the degradation of polyubiquitinated proteins. Moreover, using models of cellular aging, we find that a switch from BAG1 to BAG3 determines that aged cells use more intensively the macroautophagic system for turnover of polyubiquitinated proteins. This increased macroautophagic flux is regulated by BAG3 in concert with the ubiquitin-binding protein p62/SQSTM1. The BAG3/BAG1 ratio is also elevated in neurons during aging of the rodent brain, where, consistent with a higher macroautophagy activity, we find increased levels of the autophagosomal marker LC3-II as well as a higher cathepsin activity. We conclude that the BAG3-mediated recruitment of the macroautophagy pathway is an important adaptation of the protein quality control system to maintain protein homeostasis in the presence of an enhanced pro-oxidant and aggregation-prone milieu characteristic of aging
Real-time 6-DoF Pose Estimation by an Event-based Camera using Active LED Markers
Real-time applications for autonomous operations depend largely on fast and
robust vision-based localization systems. Since image processing tasks require
processing large amounts of data, the computational resources often limit the
performance of other processes. To overcome this limitation, traditional
marker-based localization systems are widely used since they are easy to
integrate and achieve reliable accuracy. However, classical marker-based
localization systems significantly depend on standard cameras with low frame
rates, which often lack accuracy due to motion blur. In contrast, event-based
cameras provide high temporal resolution and a high dynamic range, which can be
utilized for fast localization tasks, even under challenging visual conditions.
This paper proposes a simple but effective event-based pose estimation system
using active LED markers (ALM) for fast and accurate pose estimation. The
proposed algorithm is able to operate in real time with a latency below
\SI{0.5}{\milli\second} while maintaining output rates of \SI{3}{\kilo \hertz}.
Experimental results in static and dynamic scenarios are presented to
demonstrate the performance of the proposed approach in terms of computational
speed and absolute accuracy, using the OptiTrack system as the basis for
measurement.Comment: 14 pages, 12 figures, this paper has been accepted to WACV 202
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