Fetal phonocardiography is a non-invasive, completely passive and low-cost method based on sensing acoustic signals from the maternal abdomen. However, different types of interference are sensed along with the desired fetal phonocardiography. This study focuses on the comparison of fetal phonocardiography filtering using eight algorithms: Savitzky-Golay filter, finite impulse response filter, adaptive wavelet transform, maximal overlap discrete wavelet transform, variational mode decomposition, empirical mode decomposition, ensemble empirical mode decomposition, and complete ensemble empirical mode decomposition with adaptive noise. The effectiveness of those methods was tested on four types of interference (maternal sounds, movement artifacts, Gaussian noise, and ambient noise) and eleven combinations of these disturbances. The dataset was created using two synthetic records r01 and r02, where the record r02 was loaded with higher levels of interference than the record r01. The evaluation was performed using the objective parameters such as accuracy of the detection of S1 and S2 sounds, signal-to-noise ratio improvement, and mean error of heart interval measurement. According to all parameters, the best results were achieved using the complete ensemble empirical mode decomposition with adaptive noise method with average values of accuracy = 91.53% in the detection of S1 and accuracy = 68.89% in the detection of S2. The average value of signal-to-noise ratio improvement achieved by complete ensemble empirical mode decomposition with adaptive noise method was 9.75 dB and the average value of the mean error of heart interval measurement was 3.27 ms.
In this paper, a second-order asynchronous delta-sigma modulator (ADSM) is proposed based on the active-RCintegrators. The ADSM is implemented in the 0.18 μ m CMOS Logic or Mixed-Signal/RF, General Purpose process from the Taiwan Semiconductor Manufacturing Company with a center frequency of 848 kHz at a supply voltage of 1 V with a 92 dB peak signal-to-noise and distortion ratio ( S N D R ), which corresponds to 15 bit resolution. These parameters were achieved in all the endogenous bioelectric signals bandwidth of 10 kHz. The ADSM dissipated 295 μ W and had an area of 0.54 mm 2 . The proposed ADSM with a high resolution, wide bandwidth, and rail-to-rail input voltage range provides the universal solution for endogenous bioelectric signal processing.
- Keywords
- asynchronous delta-sigma modulator (ADSM), biomedical signals, biosensors, center frequency, operational amplifier,
- MeSH
- Signal Processing, Computer-Assisted * MeSH
- Semiconductors * MeSH
- Signal-To-Noise Ratio MeSH
- Publication type
- Letter MeSH
- Geographicals
- Taiwan MeSH
Mast cells play crucial roles in both innate and adaptive arms of the immune system. Along with basophils, mast cells are essential effector cells for allergic inflammation that causes asthma, allergic rhinitis, food allergy and atopic dermatitis. Mast cells are usually increased in inflammatory sites of allergy and, upon activation, release various chemical, lipid, peptide and protein mediators of allergic reactions. Since antigen/immunoglobulin E (IgE)-mediated activation of these cells is a central event to trigger allergic reactions, innumerable studies have been conducted on how these cells are activated through cross-linking of the high-affinity IgE receptor (FcεRI). Development of mature mast cells from their progenitor cells is under the influence of several growth factors, of which the stem cell factor (SCF) seems to be the most important. Therefore, how SCF induces mast cell development and activation via its receptor, KIT, has been studied extensively, including a cross-talk between KIT and FcεRI signaling pathways. Although our understanding of the signaling mechanisms of the FcεRI and KIT pathways is far from complete, pharmaceutical applications of the knowledge about these pathways are underway. This review will focus on recent progresses in FcεRI and KIT signaling and chemotaxis.
- Keywords
- Chemotaxis, IgE receptor, KIT receptor, Mast cell, Plasma membrane, Signal transduction,
- MeSH
- Chemotaxis * drug effects MeSH
- Humans MeSH
- Mast Cells cytology drug effects MeSH
- Signal Transduction * drug effects MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Review MeSH
- Research Support, N.I.H., Extramural MeSH
Microfluidics systems can be fabricated in various ways using original silicon glass systems, with easy Si processing and surface modifications for subsequent applications such as cell seeding and their study. Fluorescent imaging of cells became a standard technique for the investigation of cell behavior. Unfortunately, high sensitivity fluorescent imaging, e.g., using total internal reflection fluorescence (TIRF) microscopy, is problematic in these microfluidic systems because the uneven surfaces of the silicon channels' bottoms affect light penetration through the optical filters. In this work, we study the nature of the phenomenon, finding that the problem can be rectified by using a silicon-on-insulator (SOI) substrate, defining the channel depth by the thickness of the top Si layer, and halting the etching at the buried SiO2 layer. Then the fluorescent background signal drops by = 5 times, corresponding to the limit of detection drop from = 0.05 mM to = 50 nM of fluorescein. We demonstrate the importance of a flat surface using TIRF-based single-molecule detection, improving the signal to a noise ratio more than 18 times compared to a conventional Si wafer. Overall, using very high-quality SOI substrates pays off, as it improves the fluorescence image quality due to the increase in signal-to-noise ratio. Concerning the cost of microfluidic device fabrication-design, mask fabrication, wafer processing, and device testing-the initial SOI wafer cost is marginal, and using it improves the system performance.
- MeSH
- Silicon * chemistry MeSH
- Microfluidics * MeSH
- Nanotechnology methods MeSH
- Silicon Dioxide MeSH
- Signal-To-Noise Ratio MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Silicon * MeSH
- Silicon Dioxide MeSH
The main bacterial pathway for inserting proteins into the plasma membrane relies on the signal recognition particle (SRP), composed of the Ffh protein and an associated RNA component, and the SRP-docking protein FtsY. Eukaryotes use an equivalent system of archaeal origin to deliver proteins into the endoplasmic reticulum, whereas a bacteria-derived SRP and FtsY function in the plastid. Here we report on the presence of homologs of the bacterial Ffh and FtsY proteins in various unrelated plastid-lacking unicellular eukaryotes, namely Heterolobosea, Alveida, Goniomonas, and Hemimastigophora. The monophyly of novel eukaryotic Ffh and FtsY groups, predicted mitochondrial localization experimentally confirmed for Naegleria gruberi, and a strong alphaproteobacterial affinity of the Ffh group, collectively suggest that they constitute parts of an ancestral mitochondrial signal peptide-based protein-targeting system inherited from the last eukaryotic common ancestor, but lost from the majority of extant eukaryotes. The ability of putative signal peptides, predicted in a subset of mitochondrial-encoded N. gruberi proteins, to target a reporter fluorescent protein into the endoplasmic reticulum of Trypanosoma brucei, likely through their interaction with the cytosolic SRP, provided further support for this notion. We also illustrate that known mitochondrial ribosome-interacting proteins implicated in membrane protein targeting in opisthokonts (Mba1, Mdm38, and Mrx15) are broadly conserved in eukaryotes and nonredundant with the mitochondrial SRP system. Finally, we identified a novel mitochondrial protein (MAP67) present in diverse eukaryotes and related to the signal peptide-binding domain of Ffh, which may well be a hitherto unrecognized component of the mitochondrial membrane protein-targeting machinery.
- Keywords
- Ffh, FtsY, LECA, evolution, mitochondrion, protein targeting, protists, signal recognition particle,
- MeSH
- Bacterial Proteins genetics MeSH
- Biological Evolution * MeSH
- Genome, Mitochondrial * MeSH
- Naegleria genetics MeSH
- Escherichia coli Proteins genetics MeSH
- Receptors, Cytoplasmic and Nuclear genetics MeSH
- Sequence Homology, Nucleic Acid MeSH
- Signal Recognition Particle genetics MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Bacterial Proteins MeSH
- Ffh protein, E coli MeSH Browser
- FtsY protein, Bacteria MeSH Browser
- Escherichia coli Proteins MeSH
- Receptors, Cytoplasmic and Nuclear MeSH
- Signal Recognition Particle MeSH
As it was mentioned in the previous part of this work (Part I)-the advanced signal processing methods are one of the quickest and the most dynamically developing scientific areas of biomedical engineering with their increasing usage in current clinical practice. In this paper, which is a Part II work-various innovative methods for the analysis of brain bioelectrical signals were presented and compared. It also describes both classical and advanced approaches for noise contamination removal such as among the others digital adaptive and non-adaptive filtering, signal decomposition methods based on blind source separation, and wavelet transform.
Comparison and classification of organisms based on molecular data is an important task of computational biology, since at least parts of DNA sequences for many organisms are available. Unfortunately, methods for comparison are computationally very demanding, suitable only for short sequences. In this paper, we focus on the redundancy of genetic information stored in DNA sequences. We proposed rules for downsampling of DNA signals of cumulated phase. According to the length of an original sequence, we are able to significantly reduce the amount of data with only slight loss of original information. Dyadic wavelet transform was chosen for fast downsampling with minimum influence on signal shape carrying the biological information. We proved the usability of such new short signals by measuring percentage deviation of pairs of original and downsampled signals while maintaining spectral power of signals. Minimal loss of biological information was proved by measuring the Robinson-Foulds distance between pairs of phylogenetic trees reconstructed from the original and downsampled signals. The preservation of inter-species and intra-species information makes these signals suitable for fast sequence identification as well as for more detailed phylogeny reconstruction.
- Keywords
- Compression, Cumulated phase, DWT, Downsampling, Genomic signal, Phylogeny, Sequence identification,
- MeSH
- Phylogeny * MeSH
- Genome * MeSH
- Models, Genetic * MeSH
- Sequence Analysis, DNA methods MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Expression takes place for most of the jasmonic acid (JA)-induced genes in a COI1-dependent manner via perception of its conjugate JA-Ile in the SCFCOI1-JAZ co-receptor complex. There are, however, numerous genes and processes, which are preferentially induced COI1-independently by the precursor of JA, 12-oxo-phytodienoic acid (OPDA). After recent identification of the Ile-conjugate of OPDA, OPDA-Ile, biological activity of this compound could be unequivocally proven in terms of gene expression. Any interference of OPDA, JA, or JA-Ile in OPDA-Ile-induced gene expression could be excluded by using different genetic background. The data suggest individual signaling properties of OPDA-Ile. Future studies for analysis of an SCFCOI1-JAZ co-receptor-independent route of signaling are proposed.
- Keywords
- 12-oxo-phytodienoic acid (OPDA), JA-Ile perception, OPDA-Ile-induced gene expression, SCFCOI1-JAZ coreceptor complex, jasmonic acid (JA), jasmonoyl-isoleucine (JA-Ile),
- MeSH
- Arabidopsis metabolism MeSH
- Cyclopentanes metabolism MeSH
- Isoleucine analogs & derivatives metabolism MeSH
- Fatty Acids, Unsaturated metabolism MeSH
- Oxylipins metabolism MeSH
- Arabidopsis Proteins metabolism MeSH
- Plant Growth Regulators metabolism MeSH
- Signal Transduction physiology MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- 12-oxophytodienoic acid MeSH Browser
- Cyclopentanes MeSH
- Isoleucine MeSH
- jasmonic acid MeSH Browser
- jasmonoyl-isoleucine MeSH Browser
- Fatty Acids, Unsaturated MeSH
- Oxylipins MeSH
- Arabidopsis Proteins MeSH
- Plant Growth Regulators MeSH
Fetal electrocardiography is among the most promising methods of modern electronic fetal monitoring. However, before they can be fully deployed in the clinical practice as a gold standard, the challenges associated with the signal quality must be solved. During the last two decades, a great amount of articles dealing with improving the quality of the fetal electrocardiogram signal acquired from the abdominal recordings have been introduced. This article aims to present an extensive literature survey of different non-adaptive signal processing methods applied for fetal electrocardiogram extraction and enhancement. It is limiting that a different non-adaptive method works well for each type of signal, but independent component analysis, principal component analysis and wavelet transforms are the most commonly published methods of signal processing and have good accuracy and speed of algorithms.
- Keywords
- digital signal processing, fetal electrocardiogram extraction, fetal monitoring, non-adaptive filtering,
- MeSH
- Algorithms MeSH
- Principal Component Analysis MeSH
- Electrodes MeSH
- Electrocardiography methods MeSH
- Humans MeSH
- Fetus physiology MeSH
- Signal Processing, Computer-Assisted * MeSH
- Wavelet Analysis MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
In the submitted review the author pays attention to mechanisms of control of insulin secretion and the mutual interaction of other messengers (cAMP, calcium and inisitol triphosphate) with special attention to the calcium signal which plays a most important role in the stimulation of the excitable B cell. The trigger of the two-stage insulin secretion is cyclic accumulation of calcium in the cytosol of the B cell and the mutual harmony between calcium of the intra- and extracellular compartment. In the early stage of insulin secretion in particular the intracellular compartment is the source of calcium; from there the ion is released due to the action of inositol triphosphate (IP3) activated by phospholipase C. Calcium of the extracellular compartment is mobilized also in the early secretory stage by opening of the depolarization-dependent calcium channels, it plays, however, a more important part during the second stage. Activation of the other messengers, incl. the calcium signal, depends on the type of secretagogue stimulus. During systemic changes of calcium homeostasis in vivo the calcium signal of the B cell is activated or inhibited in different ways. In the course of hypercalcaemia, in particular if acute, the direct influence of calcium ions on insulin secretion is modulated by further factors, e.g. somatostatin, calcitonin, cholecystokinin, glucagon, adrenocortical hormones, opioids and other substances released into the blood stream. In chronic hypercalcaemia which is the result of primary hyperparathyroidism or vitamin D intoxication the action of calcium on the metabolic and hormonal response is enhanced by the ionophoretic action of parathormone or active vitamin D metabolites.(ABSTRACT TRUNCATED AT 250 WORDS)
- MeSH
- Insulin metabolism MeSH
- Islets of Langerhans metabolism MeSH
- Humans MeSH
- Insulin Secretion MeSH
- Calcium physiology MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
- Names of Substances
- Insulin MeSH
- Calcium MeSH
