90 research outputs found
The Role of Hypoxia on PORCN and WLS Expression in Human Embryonic Kidney (HEK293T) and Human Colon Cancer (HCT-116T) Cells
No full textWNT proteins activate different intracellular signal transduction pathways, regulate cell proliferation, adult tissue homeostasis and the progression of disease. In this thesis, I examine the WNT modifying proteins: Porcupine (PORCN) and GPR177/Wntless (WLS). PORCN is responsible for palmitoylation of WNT proteins, while WLS has been suggested to be responsible for their glycosylation. Given that tumor microenvironments in the body are low in oxygen (hypoxic), I hypothesized that PORCN and WLS are regulated by the Hypoxia-Inducible Factor (HIF) transcription factors. We used RNA interference to knockdown HIF-1 alpha expression in HCT116 cells to determine how loss of HIF-1 alpha affected PORCN, WLS and WNT3A expression. We provide the first evidence that PORCN, WLS and WNT3A may be directly regulated by HIF-1 alpha in response to hypoxia. PORCN and WLS proteins may also impact WNT3A post-transcriptional modifications under these conditions
Improving the DGNSS performance of Eurofix Using WLS algorithms, focusing on Temporal decorrelation effects
No full textEurofix is an integrated navigation system, which combines Differential GNSS and Loran-C. The Loran-C system is used to transmit messages which contain differential corrections for GNSS by additional modulation of the transmitted signals. It has been shown that reliable data transmission using Loran-C stations up to 1000 km distance is feasible. The differential corrections are generated by a DGNSS reference station located at the Loran-C transmitter site, providing DGNSS service to all users within the datalink range. Unfortunately, different time varying conditions at the DGNSS reference station and GNSS user position, introduce positioning errors. This paper mainly focuses on the temporal aspects of the errors. In the current implementation of Eurofix the calculation ofposition is solved by means of an ordinary least squares algorithm using at least 5 measured satellite range measurements. When using Weighted Least Squares (WLS), extra available information about the error-sources of GNSS and DGNSS can be taken into account. This way higher positioning accuracies can be obtained. The weight factors of WLS are related to the measurements-error-properties caused by the earth 's atmosphere and the data latency of the Eurofix communication link. Another option for positioning could be to use a Kalman filter. However it will be shown that the conditions for this filter are currently not met by the Eurofix measurements. Finally the theory is put into practice and some interesting real-life test results are presented, showing that the already high accuracy can still be improved.Electrical Engineering, Mathematics and Computer ScienceTelecommunicatie- en Verkeersbegeleidingssysteme
Optimization of WLS fiber readout for the HERD calorimeter
No full textA novel 3-D calorimeter, composed of about 7500 LYSO cubes, is the key and
crucial detector of the High Energy cosmic-Radiation Detection (HERD) facility
to be installed onboard the China Space Station. Energy deposition from cosmic
ray in each LYSO cube is translated by multiple wavelength shifting (WLS)
fibers for multi-range data acquisition and real-time triggering.
In this study, various methods of surface finish and encapsulation of the
LYSO cube were investigated to optimize the amplitude from the WLS fiber end
with the aim of improving the signal-to-noise ratio of Intensified scientific
CMOS (IsCMOS) collection. The LYSO cube with five rough surfaces and a specular
reflector achieves the maximum amplitude at the low-range fiber end, which is
increased by roughly 44% compared to the polished cube with PTFE wrapping.
The non-uniformity of amplitude at different positions on the LYSO cube
surface was measured by X-ray and the positional correlation factor was derived
for the entire cube. A simulation based on HERD CALO was conducted, which
revealed that both the LYSO cube with five rough surfaces and the cube with
rough bottom face exhibit superior energy resolution for electrons compared to
the other two configurations
Distinct requirements of wls, wnt9a, wnt5b and gpc4 in regulating chondrocyte maturation and timing of endochondral ossification
No full textFormation of the mandible requires progressive morphologic change, proliferation, differentiation and organization of chondrocytes preceding osteogenesis. The Wnt signaling pathway is involved in regulating bone development and maintenance. Chondrocytes that are fated to become bone require Wnt to polarize and orientate appropriately to initiate the endochondral ossification program. Although the canonical Wnt signaling has been well studied in the context of bone development, the effects of non-canonical Wnt signaling in regulating the timing of cartilage maturation and subsequent bone formation in shaping ventral craniofacial structure is not fully understood.. Here we examined the role of the non-canonical Wnt signaling pathway (wls, gpc4, wnt5b and wnt9a) in regulating zebrafish Meckel's cartilage maturation to the onset of osteogenic differentiation. We found that disruption of wls resulted in a significant loss of craniofacial bone, whereas lack of gpc4, wnt5b and wnt9a resulted in severely delayed endochondral ossification. This study demonstrates the importance of the non-canonical Wnt pathway in regulating coordinated ventral cartilage morphogenesis and ossification
Optimal design of infinite impulse response digital filter banks
No full textIn this report, the author elaborates the sequential weighted infinite impulse reponse (IIR) filter banks (FB). This method converts the original WLS design problem into a sequence of WLS sub-problems. In eac of the WLS sub-problem, only one secord-order factor (SOF) of the denominator and numerator is updated and iteratively solved by a constrained WLS algorithm.Bachelor of Engineerin
Optimal design of infinite impulse response digital filter banks
No full textIn this report, the author elaborates the sequential weighted infinite impulse reponse (IIR) filter banks (FB). This method converts the original WLS design problem into a sequence of WLS sub-problems. In eac of the WLS sub-problem, only one secord-order factor (SOF) of the denominator and numerator is updated and iteratively solved by a constrained WLS algorithm.Bachelor of Engineerin
Inference of reactive transport model parameters using a Bayesian multivariate approach
No full textParameter estimation of subsurface transport models from multispecies data requires the definition of an objective function that includes different types of measurements. Common approaches are weighted least squares (WLS), where weights are specified a priori for each measurement, and weighted least squares with weight estimation (WLS(we)) where weights are estimated from the data together with the parameters. In this study, we formulate the parameter estimation task as a multivariate Bayesian inference problem. The WLS and WLS(we) methods are special cases in this framework, corresponding to specific prior assumptions about the residual covariance matrix. The Bayesian perspective allows for generalizations to cases where residual correlation is important and for efficient inference by analytically integrating out the variances (weights) and selected covariances from the joint posterior. Specifically, the WLS and WLS(we) methods are compared to a multivariate (MV) approach that accounts for specific residual correlations without the need for explicit estimation of the error parameters. When applied to inference of reactive transport model parameters from column-scale data on dissolved species concentrations, the following results were obtained: (1) accounting for residual correlation between species provides more accurate parameter estimation for high residual correlation levels whereas its influence for predictive uncertainty is negligible, (2) integrating out the (co)variances leads to an efficient estimation of the full joint posterior with a reduced computational effort compared to the WLS(we) method, and (3) in the presence of model structural errors, none of the methods is able to identify the correct parameter values.Water ManagementCivil Engineering and Geoscience
Structure of amplified DNA in different Syrian hamster cell lines resistant to N-(phosphonacetil)-L-aspartate.
No full textSyrian hamster cell lines selected in multiple steps for resistance to high levels of N-(phosphonacetyl)-L-aspartate (PALA) contain many copies of the gene coding for the pyrimidine pathway enzyme CAD. Approximately 500 kilobases of additional DNA was coamplified with each copy of the CAD gene in several cell lines. To investigate its structure and organization, we cloned ca. 162 kilobases of coamplified DNA from cell line 165-28 and ca. 68 kilobases from cell line B5-4, using a screening method based solely on the greater abundance of amplified sequences in the resistant cells. Individual cloned fragments were then used to probe Southern transfers of genomic DNA from 12 different PALA-resistant mutants and the wild-type parents. A contiguous region of DNA ca. 44 kilobases long which included the CAD gene was amplified in all 12 mutants. However, the fragments cloned from 165-28 which were external to this region were not amplified in any other mutant, and the external fragments cloned from B5-4 were not amplified in two of the mutants. These results suggest that movement or major rearrangement of DNA may have accompanied some of the amplification events. We also found that different fragments were amplified to different degrees within a single mutant cell line. We conclude that the amplified DNA was not comprised of identical, tandemly arranged units. Its structure was much more complex and was different in different mutants. Several restriction fragments containing amplified sequences were found only in the DNA of the mutant cell line from which they were isolated and were not detected in DNA from wild-type cells or from any other mutant cells. These fragments contained novel joints created by rearrangement of the DNA during amplification. The cloned novel fragments hybridized only to normal fragments in every cell line examined, except for the line from which each novel fragment was isolated or the parental population for that line. This result argues that "hot spots" for forming novel joints are rare or nonexistent
The Art of Translation and the Art of Editing
No full textThe article presents various issues connected with cooperation between literary translators and their editors in the process of publication of translations of literary works within the frame of reference of Polish publishing market of the recent decades. The author proposes a list of qualities which should be expected from a good editor of literary translations. The issue of training editors specializing in working with translators is discussed as well, although the author stresses the importance of practice over theoretical education, available on a rather limited scale in Poland. Further part of the article warns against possible dangers resulting from editors’ lack of competence. The importance of “peer edition” is also stressed as an important stage in the process of translation
Risk factors associated with near-falls and falls in community-dwelling older adults : a preliminary report of a longitudinal cohort study
No full text202306 bcwwNot applicableSelf-fundedThe author(s) received no specific funding for this work.Copyright retained by autho
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