478 research outputs found
Survey Configuration for Terrestrial Laser Scanning : Aufnahmekonfiguration für Terrestrisches Laserscanning
Despite the enormous popularity of terrestrial laser scanners in the field of geodesy and related sciences the vital task of viewpoint planning is mostly considered intuitively. In contrast to established acquisition techniques, such as tacheometry and classical photogrammetry, optimisation of the acquisition configuration cannot be conducted based on assumed object coordinates, as these would change in dependence to the chosen viewpoint. Hence, this article discusses on how laser scans can be simulated based on predefined viewpoints and a given 3D model. Afterwards the task of viewpoint planning is observed from two perspectives namely regarding the achievable precision in the field as well as from an economic point of view in the context of data acquisition.Trotz der enormen Popularität von terrestrischen Laserscannern in der Geodäsie und benachbarten Fachdisziplinen wird die grundlegende Aufgabe der Standpunktplanung zumeist intuitiv gelöst. Im Gegensatz zum Vorgehen bei etablierten Erfassungsmethoden wie Tachymetrie und klassische Photogrammetrie, kann die Optimierung der Aufnahmekonfiguration nicht anhand fest vorgegebener Objektkoordinaten erfolgen, da sich die Punktverteilung beim Laserscanning in Abhängigkeit vom gewählten Aufnahmestandpunkt ändert. Daher wird in diesem Beitrag zunächst aufgezeigt, wie Laserscans unter Verwendung eines 3D-Modells des zu erfassenden Objekts sowie vorgegebener Standpunkte simuliert werden können. Danach wird die Aufgabe der Standpunktplanung von zwei Seiten betrachtet, nämlich in Bezug auf die erreichbare Genauigkeit sowie unter ökonomischen Gesichtspunkten im Zusammenhang mit der Datenerfassung
Differential clinical efficacy of anti-CD4 monoclonal antibodies in rat adjuvant arthritis is paralleled by differential influence on NF-κB binding activity and TNF-α secretion of T cells
The aim of this study was to analyze the differential effects of three anti-CD4 monoclonal antibodies (mAbs) (with distinct epitope specifities) in the treatment of rat adjuvant arthritis (AA) and on T-cell function and signal transduction. Rat AA was preventively treated by intraperitoneal injection of the anti-CD4 mAbs W3/25, OX35, and RIB5/2 (on days -1, 0, 3, and 6, i.e. 1 day before AA induction, on the day of induction [day 0], and thereafter). The effects on T-cell reactivity in vivo (delayed-type hypersensitivity), ex vivo (ConA-induced proliferation), and in vitro (mixed lymphocyte culture) were assessed. The in vitro effects of anti-CD4 preincubation on T-cell receptor (TCR)/CD3-induced cytokine production and signal transduction were also analyzed. While preventive treatment with OX35 and W3/25 significantly ameliorated AA from the onset, treatment with RIB5/2 even accelerated the onset of AA by approximately 2 days (day 10), and ameliorated the arthritis only in the late phase (day 27). Differential clinical effects at the onset of AA were paralleled by a differential influence of the mAbs on T-cell functions, i.e. in comparison with OX35 and W3/25, the 'accelerating' mAb RIB5/2 failed to increase the delayed-type hypersentivity (DTH) to Mycobacterium tuberculosis, increased the in vitro tumor necrosis factor (TNF)-α secretion, and more strongly induced NF-κB binding activity after anti-CD4 preincubation and subsequent TCR/CD3-stimulation. Depending on their epitope specificity, different anti-CD4 mAbs differentially influence individual proinflammatory functions of T cells. This fine regulation may explain the differential efficacy in the treatment of AA and may contribute to the understanding of such treatments in other immunopathologies
Arterial Embolism After Facial Fat Grafting: A Systematic Literature Review
BACKGROUND: While autologous fat grafting of the face is considered a generally safe procedure, severe complications such as arterial embolism (AE) have been reported.
OBJECTIVE: To summarize data on injection-related visual compromise, stroke, and death caused by arterial embolism after facial fat transplantation.
MATERIALS AND METHODS: Plastic surgery societies were contacted for reports on AE after autologous facial fat injection. In addition, a systematic literature review was performed. Data extracted included study design, injection site/technique, symptoms, management, outcome, and etiology.
RESULTS: 61 patients with a mean age of 33.56 ± 11.45 years were reported. Injections targeted the glabella or multiple facial regions (both n = 16/61, 26.2%) most commonly, followed by injections in the temples (n = 10/61, 16.4%) and the forehead (n = 9/61, 14.8%). The mean volume injected was 21.5 ± 21.5 ml. Visual symptoms were described most frequently (n = 24/58, 41.4%) followed by neurological symptoms (n = 20/58, 34.5%), or both (n = 13/58, 22.4%). Ophthalmic artery (OA, n = 26/60, 43.3%), anterior or middle cerebral artery (CA, n = 11/60, 18.3%) or both (n = 14/60, 23.3%) were most frequently occluded. Outcome analysis revealed permanent vision loss in all patients with OA occlusion (n = 26/26, 100%), neurological impairment in most patients with CA occlusion (n = 8/10, 80%), and vision loss in most patients suffering from both OA and CA occlusion (n = 7/11, 63.6%). Six patients died following embolisms.
CONCLUSIONS: AE causes severe complications such as blindness, stroke, and death. Due to a lack of high-quality data, no evidence-based treatment algorithms exist. To increase patient safety, a database collecting cases and complications should be established
Silencing of retrotransposons in Dictyostelium by DNA methylation and RNAi
We have identified a DNA methyltransferase of the Dnmt2 family in Dictyostelium that was denominated DnmA. Expression of the dnmA gene is downregulated during the developmental cycle. Overall DNA methylation in Dictyostelium is ∼0.2% of the cytosine residues, which indicates its restriction to a limited set of genomic loci. Bisulfite sequencing of specific sites revealed that DnmA is responsible for methylation of mostly asymmetric C-residues in the retrotransposons DIRS-1 and Skipper. Disruption of the gene resulted in a loss of methylation and in increased transcription and mobilization of Skipper. Skipper transcription was also upregulated in strains that had genes encoding components of the RNA interference pathway disrupted. In contrast, DIRS-1 expression was not affected by a loss of DnmA but was strongly increased in strains that had the RNA-directed RNA polymerase gene rrpC disrupted. A large number of siRNAs were found that corresponded to the DIRS-1 sequence, suggesting concerted regulation of DIRS-1 expression by RNAi and DNA modification. No siRNAs corresponding to the standard Skipper element were found. The data show that DNA methylation plays a crucial role in epigenetic gene silencing in Dictyostelium but that different, partially overlapping mechanisms control transposon silencing
Fresh air in the 21st century?
Ozone is an air quality problem today for much of the world's population. Regions can exceed the ozone air quality standards (AQS) through a combination of local emissions, meteorology favoring pollution episodes, and the clean-air baseline levels of ozone upon which pollution builds. The IPCC 2001 assessment studied a range of global emission scenarios and found that all but one projects increases in global tropospheric ozone during the 21st century. By 2030, near-surface increases over much of the northern hemisphere are estimated to be about 5 ppb (+2 to +7 ppb over the range of scenarios). By 2100 the two more extreme scenarios project baseline ozone increases of >20 ppb, while the other four scenarios give changes of -4 to +10 ppb. Even modest increases in the background abundance of tropospheric ozone might defeat current AQS strategies. The larger increases, however, would gravely threaten both urban and rural air quality over most of the northern hemisphere
Stabilization of G-quadruplex in the BCL2 promoter region in double-stranded DNA by invading short PNAs
Numerous regulatory genes have G-rich regions that can potentially form quadruplex structures, possibly playing a role in transcription regulation. We studied a G-rich sequence in the BCL2 gene 176-bp upstream of the P1 promoter for G-quadruplex formation. Using circular dichroism (CD), thermal denaturation and dimethyl sulfate (DMS) footprinting, we found that a single-stranded oligonucleotide with the sequence of the BCL2 G-rich region forms a potassium-stabilized G-quadruplex. To study G-quadruplex formation in double-stranded DNA, the G-rich sequence of the BCL2 gene was inserted into plasmid DNA. We found that a G-quadruplex did not form in the insert at physiological conditions. To induce G-quadruplex formation, we used short peptide nucleic acids (PNAs) that bind to the complementary C-rich strand. We examined both short duplex-forming PNAs, complementary to the central part of the BCL2 gene, and triplex-forming bis-PNAs, complementary to sequences adjacent to the G-rich BCL2 region. Using a DMS protection assay, we demonstrated G-quadruplex formation within the G-rich sequence from the promoter region of the human BCL2 gene in plasmid DNA. Our results show that molecules binding the complementary C-strand facilitate G-quadruplex formation and introduce a new mode of PNA-mediated sequence-specific targeting
K(2P)18.1 translates T cell receptor signals into thymic regulatory T cell development
It remains largely unclear how thymocytes translate relative differences in T cell receptor (TCR) signal strength into distinct developmental programs that drive the cell fate decisions towards conventional (Tconv) or regulatory T cells (Treg). Following TCR activation, intracellular calcium (Ca2+) is the most important second messenger, for which the potassium channel K(2P)18.1 is a relevant regulator. Here, we identify K(2P)18.1 as a central translator of the TCR signal into the thymus-derived Treg (tTreg) selection process. TCR signal was coupled to NF-kappa B-mediated K(2P)18.1 upregulation in tTreg progenitors. K(2P)18.1 provided the driving force for sustained Ca2+ influx that facilitated NF-kappa B- and NFAT-dependent expression of FoxP3, the master transcription factor for Treg development and function. Loss of K(2P)18.1 ion-current function induced a mild lymphoproliferative phenotype in mice, with reduced Treg numbers that led to aggravated experimental autoimmune encephalomyelitis, while a gain-of-function mutation in K(2P)18.1 resulted in increased Treg numbers in mice. Our findings in human thymus, recent thymic emigrants and multiple sclerosis patients with a dominant-negative missense K(2P)18.1 variant that is associated with poor clinical outcomes indicate that K(2P)18.1 also plays a role in human Treg development. Pharmacological modulation of K(2P)18.1 specifically modulated Treg numbers in vitro and in vivo. Finally, we identified nitroxoline as a K(2P)18.1 activator that led to rapid and reversible Treg increase in patients with urinary tract infections. Conclusively, our findings reveal how K(2P)18.1 translates TCR signals into thymic T cell fate decisions and Treg development, and provide a basis for the therapeutic utilization of Treg in several human disorders.Peer reviewe
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