scholarly journals Morphogenesis guided by 3D patterning of growth factors in biological matrices

2019 ◽  
Author(s):  
Nicolas Broguiere ◽  
Ines Lüchtefeld ◽  
Lucca Traschel ◽  
Dmitry Mazunin ◽  
Jeffrey Bode ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Three Dimensional ◽  
Single Step ◽  
Extracellular Matrices ◽  
Sortase A ◽  
Specific Interactions ◽  
Signal To Noise ◽  
Two Photon ◽  
Complex Signaling

AbstractThree-dimensional (3D) control over the placement of bioactive cues is fundamental to understand cell guidance and develop engineered tissues. Two-photon patterning (2PP) provides such placement at micro- to millimeter scale, but non-specific interactions between proteins and functionalized extracellular matrices (ECMs) restrict its use. Here we report a 2PP system based on non-fouling hydrophilic photocages and Sortase A-based enzymatic coupling offering unprecedented orthogonality and signal-to-noise ratio in both inert hydrogels and complex mammalian matrices. Improved photocaged peptide synthesis, and protein functionalization protocols with broad applicability are introduced. Importantly, the method enables 2PP in a single step and in the presence of fragile biomolecules and cells. As a corollary, we demonstrate the guidance of axons through 3D-patterned nerve growth factor (NGF) within brain-mimetic ECMs. Our approach allows for the interrogation of the role of complex signaling molecules in 3D matrices, thus helping to better understand biological guidance in tissue development and regeneration.

scholarly journals Discovery of allenyl acetylene, H2CCCHCCH, in TMC-1

2021 ◽  
Vol 647 ◽  
pp. L3 ◽  
Author(s):  
J. Cernicharo ◽  
C. Cabezas ◽  
M. Agúndez ◽  
B. Tercero ◽  
N. Marcelino ◽  
...  
Keyword(s):  
Column Density ◽  
State Of The Art ◽  
Rotational Temperature ◽  
Signal To Noise Ratio ◽  
Laboratory Data ◽  
The Other ◽  
Signal To Noise ◽  
Chemical Models ◽  
Upper Limit

We present the discovery in TMC-1 of allenyl acetylene, H2CCCHCCH, through the observation of nineteen lines with a signal-to-noise ratio ∼4–15. For this species, we derived a rotational temperature of 7 ± 1 K and a column density of 1.2 ± 0.2 × 1013 cm−2. The other well known isomer of this molecule, methyl diacetylene (CH3C4H), has also been observed and we derived a similar rotational temperature, Tr = 7.0 ± 0.3 K, and a column density for its two states (A and E) of 6.5 ± 0.3 × 1012 cm−2. Hence, allenyl acetylene and methyl diacetylene have a similar abundance. Remarkably, their abundances are close to that of vinyl acetylene (CH2CHCCH). We also searched for the other isomer of C5H4, HCCCH2CCH (1.4-Pentadiyne), but only a 3σ upper limit of 2.5 × 1012 cm−2 to the column density can be established. These results have been compared to state-of-the-art chemical models for TMC-1, indicating the important role of these hydrocarbons in its chemistry. The rotational parameters of allenyl acetylene have been improved by fitting the existing laboratory data together with the frequencies of the transitions observed in TMC-1.

The role of phosphodiesterase in aggregation of Dictyostelium discoideum

1978 ◽  
Vol 31 (1) ◽  
pp. 233-243
Author(s):  
M. Darmon ◽  
J. Barra ◽  
P. Brachet
Keyword(s):  
Dictyostelium Discoideum ◽  
Direct Contact ◽  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Extracellular Medium ◽  
Camp Phosphodiesterase ◽  
Cellular Slime Mould ◽  
Cellular Slime ◽  
Mutant Cells

The role of cAMP phosphodiesterase in the cAMP-mediated aggregation of the cellular slime mould Dictyostelium discoideum was investigated with a morphogenetic mutant defective in phosphodiesterase production. Mutant cells become capable of aggregating normally when incubated in the presence of exogenous phosphodiesterase isolated from Idictyostelium or rat brain. Direct contact between enzyme and the cell membrane is not required for this phenotypic suppression. The aggregateless character of this strain presumably results from an over-accumulation of cAMP in the extracellular medium since aggregation can be induced in the absence of added phosphodiesterase under conditions facilitating diffusion of the nucleotide. This suggests that phosphodiesterase is not involved in the generation or recognition of cAMP signals, but that the enzyme is essential in the control of the cAMP signal-to-noise ratio.

Compression of Secondary Ion Microscopy Image Sets Using a Three-dimensional Wavelet Transformation

2000 ◽  
Vol 6 (1) ◽  
pp. 68-75 ◽  
Author(s):  
Martin G. Wolkenstein ◽  
Herbert Hutter
Keyword(s):  
Image Compression ◽  
Wavelet Transformation ◽  
Signal To Noise Ratio ◽  
Three Dimensional ◽  
Compression Method ◽  
Signal To Noise ◽  
Microscopy Image ◽  
Image Set ◽  
Ion Microscopy ◽  
Secondary Ion

This article proposes a lossy three-dimensional (3-D) image compression method for 3-D secondary ion microscopy (SIMS) image sets that uses a separable nonuniform 3-D wavelet transform. A typical 3-D SIMS measurement produces relatively large amounts of data which has to be reduced for archivation purposes. Although it is possible to compress an image set slice by slice, more efficient compression can be achieved by exploring the correlation between slices. Compared to different two-dimensional (2-D) image compression methods, compression ratios of the 3-D wavelet method are about four times higher at a comparable peak signal-to-noise ratio (PSNR).

scholarly journals Energetic and Informational Components of Speech-on-Speech Masking in Binaural Speech Intelligibility and Perceived Listening Effort

2019 ◽  
Vol 23 ◽  
pp. 233121651985459 ◽  
Author(s):  
Jan Rennies ◽  
Virginia Best ◽  
Elin Roverud ◽  
Gerald Kidd
Keyword(s):  
Speech Intelligibility ◽  
Signal To Noise Ratio ◽  
Spatial Separation ◽  
Signal To Noise ◽  
Listening Effort ◽  
Complex Sound ◽  
Time Frequency ◽  
Sound Fields ◽  
Energetic Masking

Speech perception in complex sound fields can greatly benefit from different unmasking cues to segregate the target from interfering voices. This study investigated the role of three unmasking cues (spatial separation, gender differences, and masker time reversal) on speech intelligibility and perceived listening effort in normal-hearing listeners. Speech intelligibility and categorically scaled listening effort were measured for a female target talker masked by two competing talkers with no unmasking cues or one to three unmasking cues. In addition to natural stimuli, all measurements were also conducted with glimpsed speech—which was created by removing the time–frequency tiles of the speech mixture in which the maskers dominated the mixture—to estimate the relative amounts of informational and energetic masking as well as the effort associated with source segregation. The results showed that all unmasking cues as well as glimpsing improved intelligibility and reduced listening effort and that providing more than one cue was beneficial in overcoming informational masking. The reduction in listening effort due to glimpsing corresponded to increases in signal-to-noise ratio of 8 to 18 dB, indicating that a significant amount of listening effort was devoted to segregating the target from the maskers. Furthermore, the benefit in listening effort for all unmasking cues extended well into the range of positive signal-to-noise ratios at which speech intelligibility was at ceiling, suggesting that listening effort is a useful tool for evaluating speech-on-speech masking conditions at typical conversational levels.

A new method for ultrasonic detection of peel ply at the bondline of out-of-autoclave composite assemblies

2018 ◽  
Vol 53 (2) ◽  
pp. 245-259
Author(s):  
Gary S LeMay ◽  
Davood Askari
Keyword(s):  
Signal To Noise Ratio ◽  
Three Dimensional ◽  
Ultrasonic Pulse ◽  
Woven Fabric ◽  
Material System ◽  
Signal To Noise ◽  
Structural Applications ◽  
Peel Ply ◽  
Noise Ratio ◽  
Out Of Autoclave

Out-of-autoclave materials have long been an established material system for secondary structural applications; however, recent advancements in material properties allow for more advanced structural applications. Even though certain out-of-autoclave properties have achieved parity with autoclaved cured materials, out-of-autoclave materials are cured at reduced temperatures and pressures resulting in less compaction and homogeneity. The consequence is extraneous ultrasonic signals, due to internal reflections and refractions that cause attenuation, potentially masking defects leading to unidentifiable indications. Advanced algorithms were developed to improve the signal to noise ratio between constituents of similar acoustic impedance in bonded out-of-autoclave carbon fiber reinforced polymer assemblies. Conventional ultrasonic nondestructive testing techniques and analysis software cannot consistently achieve signal to noise ratios that meet quantifiable rejection thresholds of accurately sized peel ply inserts at the bonded interface of composite assemblies. Ultrasonic pulse echo with full waveform capture was used to inspect a reference standard with peel ply inserts placed between the adhesive and three-dimensional-woven fabric preform. The ultrasonic signal was produced by a 64 element array transducer with a central frequency of 2.8 MHz. Waveform post-acquisition analysis with post processing software was used to analyze and enhance the signal response between the peel ply and the bondline resulting in the final algorithm. To verify the results, the signal to noise ratio of each insert was calculated for both the raw and processed data. As the measure of detectability, the method relies on principles of statistical measurement to provide an industry standard signal to noise response of 3:1.

scholarly journals Three-Dimensional Imaging via Time-Correlated Single-Photon Counting

2020 ◽  
Vol 10 (6) ◽  
pp. 1930
Author(s):  
Chengkun Fu ◽  
Huaibin Zheng ◽  
Gao Wang ◽  
Yu Zhou ◽  
Hui Chen ◽  
...  
Keyword(s):  
3D Imaging ◽  
Single Photon ◽  
Signal To Noise Ratio ◽  
Photon Counting ◽  
Three Dimensional ◽  
Similarity Index ◽  
Signal To Noise ◽  
Single Photon Counting ◽  
Imaging Results ◽  
Noise Ratio

Three-dimensional (3D) imaging under the condition of weak light and low signal-to-noise ratio is a challenging task. In this paper, a 3D imaging scheme based on time-correlated single-photon counting technology is proposed and demonstrated. The 3D imaging scheme, which is composed of a pulsed laser, a scanning mirror, single-photon detectors, and a time-correlated single-photon counting module, employs time-correlated single-photon counting technology for 3D LiDAR (Light Detection and Ranging). Aided by the range-gated technology, experiments show that the proposed scheme can image the object when the signal-to-noise ratio is decreased to −13 dB and improve the structural similarity index of imaging results by 10 times. Then we prove the proposed scheme can image the object in three dimensions with a lateral imaging resolution of 512 × 512 and an axial resolution of 4.2 mm in 6.7 s. At last, a high-resolution 3D reconstruction of an object is also achieved by using the photometric stereo algorithm.

Compression of Secondary Ion Microscopy Image Sets Using a Three-dimensional Wavelet Transformation

2000 ◽  
Vol 6 (1) ◽  
pp. 68-75
Author(s):  
Martin G. Wolkenstein ◽  
Herbert Hutter
Keyword(s):  
Image Compression ◽  
Wavelet Transformation ◽  
Signal To Noise Ratio ◽  
Three Dimensional ◽  
Compression Method ◽  
Signal To Noise ◽  
Microscopy Image ◽  
Image Set ◽  
Ion Microscopy ◽  
Secondary Ion

Abstract This article proposes a lossy three-dimensional (3-D) image compression method for 3-D secondary ion microscopy (SIMS) image sets that uses a separable nonuniform 3-D wavelet transform. A typical 3-D SIMS measurement produces relatively large amounts of data which has to be reduced for archivation purposes. Although it is possible to compress an image set slice by slice, more efficient compression can be achieved by exploring the correlation between slices. Compared to different two-dimensional (2-D) image compression methods, compression ratios of the 3-D wavelet method are about four times higher at a comparable peak signal-to-noise ratio (PSNR).

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