noise isolation
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Cardiorespiratory signals have long been treated as "noise" in functional magnetic resonance imaging (fMRI) research, with the goal of minimizing their impact to isolate neural activity. However, there is a growing recognition that these signals, once seen as confounding variables, provide valuable insights into brain function and overall health. This shift reflects the dynamic interaction between the cardiovascular, respiratory, and neural systems, which together support brain activity. In this review, we explore the role of cardiorespiratory dynamics-such as heart rate variability (HRV), respiratory sinus arrhythmia (RSA), and changes in blood flow, oxygenation, and carbon dioxide levels-embedded within fMRI signals. These physiological signals reflect critical aspects of neurovascular coupling and are influenced by factors such as physiological stress, breathing patterns, and age-related changes. We also discuss the complexities of distinguishing these signals from neuronal activity in fMRI data, given their significant contribution to signal variability and interactions with cerebrospinal fluid (CSF). Recognizing the influence of these cardiorespiratory dynamics is crucial for improving the interpretation of fMRI data, shedding light on heart-brain and respiratory-brain connections, and enhancing our understanding of circulation, oxygen delivery, and waste elimination within the brain.
PURPOSE: Chronic obstructive pulmonary disease (COPD) is a prevalent and preventable condition that typically worsens over time. Acute exacerbations of COPD significantly impact disease progression, underscoring the importance of prevention efforts. This observational study aimed to achieve two main objectives: (1) identify patients at risk of exacerbations using an ensemble of clustering algorithms, and (2) classify patients into distinct clusters based on disease severity. METHODS: Data from portable medical devices were analyzed post-hoc using hyperparameter optimization with Self-Organizing Maps (SOM), Density-Based Spatial Clustering of Applications with Noise (DBSCAN), Isolation Forest, and Support Vector Machine (SVM) algorithms, to detect flare-ups. Principal Component Analysis (PCA) followed by KMeans clustering was applied to categorize patients by severity. RESULTS: 25 patients were included within the study population, data from 17 patients had the required reliability. Five patients were identified in the highest deterioration group, with one clinically confirmed exacerbation accurately detected by our ensemble algorithm. Then, PCA and KMeans clustering grouped patients into three clusters based on severity: Cluster 0 started with the least severe characteristics but experienced decline, Cluster 1 consistently showed the most severe characteristics, and Cluster 2 showed slight improvement. CONCLUSION: Our approach effectively identified patients at risk of exacerbations and classified them by disease severity. Although promising, the approach would need to be verified on a larger sample with a larger number of recorded clinically verified exacerbations.
- Publikační typ
- časopisecké články MeSH
BACKGROUND: Speech dysfunction represents one of the initial motor manifestations to develop in Parkinson's disease (PD) and is measurable through smartphone. OBJECTIVE: The aim was to develop a fully automated and noise-resistant smartphone-based system that can unobtrusively screen for prodromal parkinsonian speech disorder in subjects with isolated rapid eye movement sleep behavior disorder (iRBD) in a real-world scenario. METHODS: This cross-sectional study assessed regular, everyday voice call data from individuals with iRBD compared to early PD patients and healthy controls via a developed smartphone application. The participants also performed an active, regular reading of a short passage on their smartphone. Smartphone data were continuously collected for up to 3 months after the standard in-person assessments at the clinic. RESULTS: A total of 3525 calls that led to 5990 minutes of preprocessed speech were extracted from 72 participants, comprising 21 iRBD patients, 26 PD patients, and 25 controls. With a high area under the curve of 0.85 between iRBD patients and controls, the combination of passive and active smartphone data provided a comparable or even more sensitive evaluation than laboratory examination using a high-quality microphone. The most sensitive features to induce prodromal neurodegeneration in iRBD included imprecise vowel articulation during phone calls (P = 0.03) and monopitch in reading (P = 0.05). Eighteen minutes of speech corresponding to approximately nine calls was sufficient to obtain the best sensitivity for the screening. CONCLUSION: We consider the developed tool widely applicable to deep longitudinal digital phenotyping data with future applications in neuroprotective trials, deep brain stimulation optimization, neuropsychiatry, speech therapy, population screening, and beyond. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
- MeSH
- biologické markery MeSH
- chytrý telefon * MeSH
- hlas fyziologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- Parkinsonova nemoc * patofyziologie komplikace MeSH
- parkinsonské poruchy patofyziologie MeSH
- porucha chování v REM spánku * patofyziologie diagnóza MeSH
- poruchy řeči etiologie MeSH
- prodromální symptomy MeSH
- průřezové studie MeSH
- senioři MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
... conditions 27 -- 3.2 Chemical factors 28 -- 3.3 Biological agents 29 -- 3.4 Physical load 29 -- 3.5 Noise ... ... tendovaginitis Morbus de -- Quervain, digitus saltans and forearm tenosynovitis 51 -- 4.1.2.3.2 Isolated ...
1. elektronické vydání 1 online zdroj (154 stran)
Optical mapping is a fluorescence-based physiological method to image spreading of action potential in excitable tissues, such as the heart and central nervous system. Because of the requirements for high speed imaging in low light conditions, highly sensitive high-speed cameras together with an optical system with maximum photon efficiency are required. While the optimization of these two components is relatively straightforward, the choice of the perfect light source is less simple; depending on the other (usually fixed) components, various parameters may acquire different weight in decision-making process. Here we describe the rationale for building an optical mapping setup and consider the relative advantages and disadvantages of three different commonly available light sources: mercury vapor lamp (HBO), xenon lamp (XBO), and light emitting diode (LED). Using the same optical system (fluorescence macroscope) and high-speed camera (Ultima L), we have tested each of the sources for its ability to provide bright and even illumination of the field of view and measured its temporal fluctuations in intensity. Then we used each in the actual optical mapping experiment using isolated, perfused adult mouse heart or chick embryonic heart to determine the actual signal to noise ratio at various acquisition rates. While the LED sources have undergone significant improvements in the recent past, the other alternatives may still surpass them in some parameters, so they may not be the automatic number one choice for every application.
- MeSH
- akční potenciály MeSH
- fluorescenční barviva chemie MeSH
- kuřecí embryo MeSH
- myši MeSH
- srdce fyziologie MeSH
- světlo MeSH
- vápník analýza metabolismus MeSH
- zobrazování pomocí barviva citlivého na potenciál metody normy MeSH
- zvířata MeSH
- Check Tag
- kuřecí embryo MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Reliable, fast, simple and low-cost analytical procedure based on radionuclide X-ray fluorescence spectrometry (RRFS) was proposed to identify and determine heavy metals in various antitussive preparations of synthetic and biological origin. Various materials (tablet dosage forms, granules, plants) can be analyzed directly without the need of isolation of the analyzed compounds from their matrices so that errors in the analytical process are minimized. External matrices, such as Medicago sativa L. , benzoic acid, and dextran were proposed to quantify heavy metals in some problematic materials ( Farfarereae folium , effervescent tablets of medicine ACC long, hard capsules of various homeopathics, respectively) that had not allowed homogeneous implementation of standard addition of analyzed elements into the standardized tablet forms used for the RRFS analysis. The appropriate external matrices were consistent with the original ones in terms of matrix effects (e.g., background noise produced and approximate levels of naturally occurring heavy metals studied), and they allowed to prepare well defined tablets including required amounts of the standard additions of heavy metals providing proper calibration parameters. The RRFS method applied for the original or external matrices enabled an effective and economic control of antitussive preparations for selected heavy metals contents evaluated according to the established directives and laws. Hence, it is recommended for a routine use in quality control laboratories.
[11C]-PK11195 (PK11195) has been widely used with positron emission tomography (PET) to assess levels of the translocator protein 18 kDa (TSPO) as a marker of neuroinflammation. Recent ligands, such as [11C]-PBR28 and [11C]-DPA713, have improved signal-to-noise ratio and specificity for TSPO over PK11195. However, these second generation radiotracers exhibit binding differences due to a single polymorphism (rs6971) that leads to three genotypes: C/C, C/T and T/T associated with high, mixed and low binding affinities, respectively. Here we report that [3H]-DPA-713 in the presence of cholesterol or PK11195 has an accelerated dissociation rate from TSPO in platelets isolated from individuals with the T/T genotype. This allosteric interaction was not observed in platelets isolated from individuals with the C/C or C/T genotype. The results provide a molecular rationale for low binding affinity of T/T TSPO and further support the exclusion of these subjects from PET imaging studies using second generation TSPO ligands.
Brassinosteroids (BRs) are plant-specific steroid hormones that play essential roles in the regulation of many important physiological processes in plant life. Their extremely low concentrations (~pmoles/g FW) in plant tissue and huge differences in polarity of individual members within the BR family hamper their detection and quantification. To address this problem, an immunoaffinity sorbent with broad specificity and high capacity for different BR metabolites containing a monoclonal antibody (mAb) against a BR spacer (20S)-2α,3α-dihydroxy-7-oxa-7α-homo-5α-pregnane-6-one-20 carboxylic acid (BR4812) was used for the rapid and highly selective isolation of endogenous BRs containing a 2α,3α-diol in ring A from minute plant samples. This enrichment procedure was successfully applied as a sample preparation method prior to quantitative analysis of BRs in real plant tissues by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Use of immunoaffinity chromatography (IAC) increased the sensitivity of the UHPLC-MS/MS analysis owing to improvements in the BR signal-to-noise ratio (S/N) and matrix factor (MF). Although MF values of BRs analyzed in classical samples ranged from 8.9% to 47.4%, MF values for the IAC purified samples reached 44.5-96.6%. Thus, the developed IAC-UHPLC-MS/MS approach was shown to be a simple, robust, effective and extremely fast procedure requiring minute amounts of plant samples suitable for the quantitative profiling of many BR metabolites, helping to overcome the major problems associated with their determination in very complex plant matrices.
- MeSH
- Brassica napus chemie MeSH
- brassinosteroidy analýza izolace a purifikace MeSH
- chromatografie afinitní metody MeSH
- imobilizační protilátky chemie MeSH
- imunosorbenty chemie MeSH
- regulátory růstu rostlin analýza izolace a purifikace MeSH
- rostlinné extrakty chemie MeSH
- tandemová hmotnostní spektrometrie metody MeSH
- vysokoúčinná kapalinová chromatografie metody MeSH
- Publikační typ
- časopisecké články MeSH
... in the Cell -- 8 Analyzing Cells, Molecules, and vems -- CELLS AND GROWING THEM IN CULTURE -- Be Isolated ... ... IN THE LIGHT MICROSCOPE 529 -- The Light Microscope Can Resolve Details 0.2 (im Apart 530 -- Photon Noise ...
Sixth edition xxxiv, 1430 stran v různém stránkování : ilustrace (převážně barevné) ; 29 cm
- Konspekt
- Biochemie. Molekulární biologie. Biofyzika
- NLK Obory
- molekulární biologie, molekulární medicína
- NLK Publikační typ
- učebnice vysokých škol
We present a novel wavelet-based ECG delineation method with robust classification of P wave and T wave. The work is aimed on an adaptation of the method to long-term experimental electrograms (EGs) measured on isolated rabbit heart and to evaluate the effect of global ischemia in experimental EGs on delineation performance. The algorithm was tested on a set of 263 rabbit EGs with established reference points and on human signals using standard Common Standards for Quantitative Electrocardiography Standard Database (CSEDB). On CSEDB, standard deviation (SD) of measured errors satisfies given criterions in each point and the results are comparable to other published works. In rabbit signals, our QRS detector reached sensitivity of 99.87% and positive predictivity of 99.89% despite an overlay of spectral components of QRS complex, P wave and power line noise. The algorithm shows great performance in suppressing J-point elevation and reached low overall error in both, QRS onset (SD = 2.8 ms) and QRS offset (SD = 4.3 ms) delineation. T wave offset is detected with acceptable error (SD = 12.9 ms) and sensitivity nearly 99%. Variance of the errors during global ischemia remains relatively stable, however more failures in detection of T wave and P wave occur. Due to differences in spectral and timing characteristics parameters of rabbit based algorithm have to be highly adaptable and set more precisely than in human ECG signals to reach acceptable performance.
- MeSH
- algoritmy MeSH
- elektrokardiografie metody MeSH
- ischemie patofyziologie MeSH
- králíci MeSH
- lidé MeSH
- počítačové zpracování signálu * MeSH
- srdce patofyziologie MeSH
- vlnková analýza * MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
