Signal Changes Research Articles

Systematic Review on definitions of Intestinal Ultrasound Treatment Response and Remission in Inflammatory Bowel Disease.

Intestinal ultrasound (IUS) is emerging as a valuable tool to assess treatment response in inflammatory bowel disease (IBD) clinical trials. This study details how IUS defines response and remission to evaluate treatment efficacy in IBD patients. We conducted a comprehensive search of studies from 1984 to 31 March 2024, focusing on IUS use in assessing treatment efficacy in IBD. A total of 51 studies were included: 31 on Crohn's disease (CD), 12 on ulcerative colitis (UC) and 8 on IBD. Ileocolonoscopy was used as a reference standard in 53% of studies. IUS-defined response was reported in 47% of studies, with the majority (71%) using changes in bowel wall thickness (BWT) and color Doppler signals (CDS) as key indicators. IUS-defined remission was reported in 53% of studies, primarily using normalization of BWT to less than 3mm and CDS to grades 0 or 1 as criteria. Ultrasonographic activity scores were used in 16% of studies, including the Bowel Ultrasound Score (BUSS) in two CD studies, the International Bowel Ultrasound Segmental Activity Score (IBUS-SAS) in one CD study, the Milan Ultrasound Criteria (MUC) in one UC study The remaining four studies used unvalidated scores without clear definitions of response or remission. Assessment times varied, most commonly at weeks 8-16, 6 months, 12 months, and 24 months. This systematic review reveals significant variability in IUS definitions of response and remission in IBD, highlighting the need to standardize eligibility criteria and outcome measures for IUS in IBD clinical trials.

Prevalence of thoracic degenerative MRI findings and association with pain and disability: a systematic review.

To systematically review the literature on the prevalence of degenerative MRI findings in the thoracic spine and their association with pain and disability. The Medline, EMBASE, CINAHL, and CENTRAL databases were searched. Two independent reviewers screened the articles, extracted the data, and assessed the risk of bias (RoB) using a modified version of the Hoy tool for articles on prevalence and QUADAS-2 for articles on associations. The review included 23 articles describing 20 study populations: 5 general populations, 2 populations of asymptomatic volunteers, and 13 clinical populations. As the articles were highly heterogeneous, especially regarding study populations and the MRI findings assessed, a meta-analysis was not possible, and the results were presented descriptively. Prevalence estimates were reported in 21 articles, and 5 (3 study populations) had low RoB. The most frequently reported prevalence rates concerned the intervertebral discs, vertebral endplates, and the ligamentum flavum. Estimates varied considerably, with the prevalence of thoracic disc degeneration ranging from 0.2%-89% and vertebral endplate signal changes ranging from 0%-82%, depending on MRI definitions, population characteristics, and recruitment settings. Four articles investigated the association between MRI findings and spinal pain, with the RoB mainly considered low or unclear. Only two of these studies specifically examined thoracic spinal pain. None assessed the association with disability. Due to heterogeneity, few high-quality studies and few studies on individual MRI findings, no definitive conclusions could be drawn about the prevalence of thoracic degenerative MRI findings or their association with pain and disability.

A Dual-Mode Colorimetric and Fluorescence Biosensor Based on a Nucleic Acid Multiplexing Platform for the Detection of Listeria monocytogenes.

Listeria monocytogenes (L. monocytogenes) is one of the most prevalent threats, capable of inducing diverse illnesses and presenting a serious threat to public health. Herein, we demonstrate a novel dual-mode colorimetric/fluorescence biosensor based on the exponential amplification reaction and strand displacement reactions (EASDR), which has multiplexing capability that significantly promotes the anchoring and trapping of Pt nanoparticles (Pt NPs) and fluorescent dyes for sensitive detection of Listeria monocytogenes (L. monocytogenes). The method works by targeting specific bacteria with aptamers and promoting repeated EASDR to affect the immobilization of Pt NPs and fluorescent dyes in the orifice plate, which could produce changes in fluorescence and colorimetric signals. The assay achieves a detection limit of 38 CFU/mL in colorimetric and 10 CFU/mL in fluorescence. Furthermore, the developed biosensor can be applied to the analysis of raw food samples (milk), and good recoveries were obtained in spiked food samples. In summary, the dual-mode biosensor improves the accuracy of detection by simultaneously outputting two signals and shows great potential in the specific identification and detection of foodborne pathogens.

Detection of epileptogenic zones in people with epilepsy using optimized EEG-fMRI.

Concurrent electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) have been used to assist in the presurgical localization of seizure foci in people with epilepsy. Our study aimed to examine the clinical feasibility of an optimized concurrent EEG-fMRI protocol. The optimized protocol employed a fast-fMRI sequence (sampling rate=10Hz) with a spare arrangement, which allowed a time window of 1.9s for EEG recording without radio frequency noise. Patients with a diagnosis of drug-resistant epilepsy who were candidates for surgical intervention were enrolled and underwent concurrent EEG-fMRI studies to map fMRI blood oxygen level-dependent (BOLD) signal changes related to interictal epileptiform discharges. The BOLD signals were compared to those in the epileptogenic zone determined by resective cavities or radiofrequency thermocoagulation lesions. Postoperative seizure outcomes were classified according to the ILAE classification. The EEG-related BOLD results indicated that 15 of the 19 patients (78.9%) had concordant findings in the epileptogenic zone determined by surgical intervention. The percentage of patients who achieved good surgical outcomes was significantly greater in the concordant group than in the discordant group (n=9, 60.0% vs. n=0, 0%, p=0.033). Using fast MRI scan, the optimized protocol provides satisfactory accuracy (78.9%) for detecting epileptogenic zones. A concordant BOLD signal and epileptogenic zone can predict good surgical outcomes.

Case report: 10-year follow-up of a patient with neuronal intranuclear inclusion disease and a literature review

Neuronal intranuclear inclusion disease (NIID) is a rare, progressive neurodegenerative disease with variable clinical manifestations. High signals on diffusion-weighted imaging (DWI) along the corticomedullary junction (CMJ) are a specific feature of NIID. Only a few reports have observed patients for a long period and demonstrated a relationship between magnetic resonance imaging (MRI) features and clinical manifestations. Herein, we present a case of a patient with NIID who underwent a 10-year brain MRI follow-up study and a literature review. A 78-year-old woman presented with severe cognitive dysfunction and disturbances of consciousness. Her brain MRI DWI signal intensity gradually increased over 10 years, and her cognitive function progressively declined. The DWI signal changes were related to the clinical manifestations in this case. In the literature review, we analyzed patients with NIID by classifying them into subgroups and found that high signals on fluid-attenuated inversion recovery (FLAIR) and DWI were related to dementia. Although high DWI signals along the CMJ are specific to NIID, many patients also show high signals on FLAIR in the deep subcortical white matter. In our literature review, dementia could have some correlation to MRI signals. In our case with longitudinal follow up, the DWI high intensity signal expansion could have correlation to cognitive decline. We found dementia and the dementia progression may have some relation to expansion of DWI with intensity signals from the CMJ to the deep subcortical white matter. Our report highlights that DWI signal changes are strongly correlated with the clinical manifestations of NIID.

Effectiveness and safety of hypofractionated gamma knife radiosurgery for large meningiomas and those adjacent to the optic pathway and brainstem: preliminary therapeutic outcomes.

Recent technologic advancements have facilitated the use of hypofractionated Gamma Knife-based radiosurgery (HF-GKRS) to treat large lesions or those in eloquent areas. This study aimed to analyze the preliminary results of HF-GKRS for these meningiomas, and to determine its effectiveness and safety.This single-center retrospective study analyzed data of patients who underwent HF-GKRS for large meningiomas or those in eloquent areas with > 6 months of follow-up. The primary outcome was progression-free survival (PFS). The secondary outcomes were neurological deterioration, post-treatment T2 signal changes following HF-GKRS, and tumor volume changes. Volumetric analysis of the tumors after treatment was also performed to assess changes in tumor size after HF-GKRS.Overall, 24 patients with a median follow-up period of 22 months (range: 6-49 months) were included. Among them, 18 (75%) patients had tumors in close proximity to the optic pathway, and 15 (63%) patients had large lesions (> 10 cm3). The cumulative 1- and 3-year PFS rates were 100% and 92%, respectively. The cumulative 3-year rate of adverse radiation effects was 9%. Overall, 12 patients (50%) showed tumor reduction, with a median tumor reduction rate of 45% (range: 25-58%).Our preliminary results revealed that HF-GKRS for large meningiomas or those in eloquent areas is safe and effective, with satisfactory short- and mid-term PFS and low adverse radiation effects. Further research with more patients and longer follow-up periods is required.

Investigation of the October effect in very low-frequency (VLF) signals

Abstract. Subionospheric very low-frequency (VLF) radio signals are reflected by free electrons in the ionospheric D-region at about 60–90 km altitude and can propagate over long distances, which makes them useful for monitoring the state of the D-region or perturbations due to solar flares. At the D-region height, the ionosphere is mainly ionized by solar Lyman-α radiation. The reflection characteristics of VLF signals depend on the state and dynamics of the D-region, which is highly influenced by Lyman-α radiation. Although the amplitude of the received terrestrial VLF signal changes as a function of solar zenith angle over the course of the year, the VLF amplitude shows a distinctive sharp decrease around October, which is hence called the “October effect”. This study investigates the occurrence of the October effect and its dependencies on latitude and longitude. We developed a method to detect the occurrence of the October effect in the long-term VLF data and derive key parameters characterizing (start and end date, intensity) the sudden decrease in the signal amplitude. This investigation using a network of VLF stations distributed over low-, middle-, and high-latitude regions shows that the occurrence of the October effect has a clear latitudinal dependency, occurring earlier in high-latitude regions than at midlatitudes. No low-latitude signature is found.

Cell-Interface-Deciphering Lipid Nanotablet for Nanoparticle Logic Gate-Based Real-Time Single-Cell Analysis.

Analyzing the cell interface is of paramount importance in understanding how cells interact and communicate with other cells, but an advanced analytical platform that can process complex and networked interactions between cell surface ligands and receptors is lacking. Herein, we developed the cell-interface-deciphering lipid nanotablet (CID-LNT) for multiplexed real-time cell analysis. LNT is a nanoparticle-tethered lipid bilayer chip where freely diffusing plasmonic nanoparticles induce scattering signal changes. The CID-LNT transduces cell surface protein information into DNA data, which operate as nanoparticle logic gates. As a proof of concept, we detected and analyzed programmed death-ligand 1 (PD-L1) and associated immune signals (TNF-α, EGF, and IFN-γ). PD-L1 is an immune checkpoint that suppresses T cell activity with inflammatory biomolecules facilitating its expression. The CID-LNT can serve as a dynamic nanoparticle logic board, enabling the logic gate-based analysis of membrane proteins, and can be expanded to immunological synapse analysis, cell interface engineering, and molecular diagnostics.

A Novel Rhodamine-Based Fluorescent Sensor for Detection of Cu2.

In this work, a new fluorescent sensor for detecting Cu2 + was developed based on the Rhodamine derivative. It displayed strong fluorescence enhancement upon the addition of Cu2+, and other common metal ions do not significantly affect the optical properties of the sensor. This optical signal change caused solely by Cu2 + is due to the opening of the lactone amide spiro ring structure, resulting in fluorescence emission. This specific recognition endows the sensor with the ability to qualitatively and quantitatively detect Cu2+, and the conclusion was also verified through density functional theory calculations. Simultaneously, the cell imaging and zebrafish experiments proved the potential application value in biological systems.

Amplification-free sensitive detection of Staphylococcus aureus by spherical nucleic acid triggered CRISPR/Cas12a and Poly T-Cu reporter.

Aspherical nucleic acid (SNA, AuNPs-aptamer) into CRISPR/Cas12a system combined with poly T-template copper nanoparticles as fluorescence reporter was fabricatedto establish an amplification-free sensitive method for Staphylococcus aureus (S. aureus) detection. This method, named PTCas12a, utilizes the concept that the bifunction of SNA recognizes the S. aureus and triggers the Cas12a cleavage activity. Then, the Cas12a enzyme cleaves the Poly T40 to generate a signal change in Poly T-Cu fluorescence, indicating the presence or absence of the target bacteria. The PTCas12a platform demonstrated a detection limit as low as 3.0CFU/mL (3 N/S) in a wide response range of 1.0 × 101-1.0 × 106CFU/mL for S. aureus detection, which holds significant potential in ensuring food safety and preventing the spread of diseases.

Self-Powered, Flexible, Transparent Tactile Sensor Integrating Sliding and Proximity Sensing

Tactile sensing is currently a research hotspot in the fields of intelligent perception and robotics. The method of converting external stimuli into electrical signals for sensing is a very effective strategy. Herein, we proposed a self-powered, flexible, transparent tactile sensor integrating sliding and proximity sensing (SFTTS). The principle of electrostatic induction and contact electrification is used to achieve tactile response when external objects approach and slide. Experiments show that the material type, speed, and pressure of the perceived object can cause the changes of the electrical signal. In addition, fluorinated ethylene propylene (FEP) is used as the contact electrification layer, and indium tin oxide (ITO) is used as the electrostatic induction electrode to achieve transparency and flexibility of the entire device. By utilizing the transparency characteristics of this sensor to integrate with optical cameras, it is possible to achieve integrated perception of tactile and visual senses. This has great advantages for applications in the field of intelligent perception and is expected to be integrated with different types of optical sensors in the future to achieve multimodal intelligent perception and sensing technology, which will contribute to the intelligence and integration of robot sensing.

To bind or not to bind: diagnosing false positives for 1:1 binding to G-Protein

ABSTRACT Binding studies are ubiquitous in chemistry, but their extensive usefulness is undermined by false positive and false negative results. Centering on the G-protein mini-Gs, we present a thorough study with both simulated and experimental spectrophotometric titration data to diagnose the validity of both binding and non-binding models. Without the use of statistical tests like the Bayesian Information Criterion (BIC) and data reconstruction fractions, spurious binding models may go undetected. Furthermore, if the signal change upon binding is too minute, false negatives can also result. Delineating such issues is paramount to effective science.

Zero-echo time imaging achieves whole brain activity mapping without ventral signal loss in mice.

Functional MRI (fMRI) is an important tool for investigating functional networks. However, the widely used fMRI with T2*-weighted imaging in rodents has the problem of signal lack in the lateral ventral area of forebrain including the amygdala, which is essential for not only emotion but also noxious pain. Here, we scouted the zero-echo time (ZTE) sequence, which is robust to magnetic susceptibility and motion-derived artifacts, to image activation in the whole brain including the amygdala following the noxious stimulation to the hind paw. ZTE exhibited higher spatial and temporal signal-to-noise ratios than conventional fMRI sequences. Electrical sensory stimulation of the hind paw evoked ZTE signal increase in the primary somatosensory cortex. Formalin injection into the hind paw evoked early and latent change of ZTE signals throughout the whole brain including the subregions of amygdala. Furthermore, resting-state fMRI using ZTE demonstrated the functional connectivity, including that of the amygdala. These results indicate the feasibility of ZTE for whole brain fMRI including the amygdala and we first show acute and latent activity in different subnuclei of the amygdala complex after nociceptive stimulation.

The Road to a Realistic 3D Model for Estimating R2 and R2* Relaxation Versus Gd-DTPA Concentration in Whole Blood and Brain Tumor Vasculature.

Dynamic susceptibility contrast (DSC) MRI is commonly part of brain tumor imaging. For quantitative analysis, measurement of the arterial input function and tissue concentration time curve is required. Usually, a linear relationship between the MR signal changes and contrast agent concentration ([Gd]) is assumed, even though this is a known simplification. The aim of this study was to develop a realistic 3D simulation model as an efficient method to assess the relationship between ΔR2 (*) and [Gd] both in whole blood and brain tissue. We modified an open-source 3D simulation model to study different red blood cell configurations for assessing whole-blood ΔR2 (*) versus [Gd]. The results were validated against previously obtained 2D data and invitro data. Furthermore, hematocrit levels (30%-50%) and field strengths (1.5-3.0-7.0 T) were varied. Subsequently, realistic tumor vascular networks were derived from intraoperative high framerate Doppler ultrasound data to study the influence of vascular structure and orientation with respect to the main magnetic field (1.5-3.0-7.0 T) for the calculation of ΔR2 (*) versus [Gd] in brain tissue. For whole blood, good agreement of the 3D model was found with invitro and 2D simulation data when red blood cells were aligned with the blood flow. For brain tissue, minor differences were found between the vascular networks. The effect of vessel direction with respect to B0 was apparent in case of clear directionality of the main vessels. The dependency on field strength agreed with previous reports. In conclusion, we have shown that the relationship between ΔR2 (*) and [Gd] is affected by the organization of red blood cells and orientation of blood vessels with respect to the main magnetic field, as well as the field strength. These findings are important for further optimization of the realistic 3D model that could eventually be used to improve the estimation of hemodynamic parameters from DSC-MRI.

Correlation of Intraoperative Neuromonitoring (IONM) Signal Changes with Clinical Outcomes in Patients with Compressive Cervical Myelopathy: A Prospective Study

Correlation of Intraoperative Neuromonitoring (IONM) Signal Changes with Clinical Outcomes in Patients with Compressive Cervical Myelopathy: A Prospective Study

Secondary surge phenomenon of the compressor during surge recovery and its mechanism analysis

This paper explores the secondary surge during compressor surge recovery. Utilizing the test rig at Northwestern Polytechnical University, the surge is induced by tail cone adjustment. A secondary surge follows tail cone retraction post-initial surge. Signal changes are analyzed, and causes are expounded from energy and fluid dynamics. Experimental outcomes confirm the secondary surge is repeatable and observable under set conditions. Its frequency stabilizes at 4.83 Hz across consecutive events and rotor axes, being system-inherent. From energy, with enthalpy as a proxy, potential energy amasses as the compressor interacts with cavity potential shifts from tail cone changes. Exceeding kinetic supply instigates violent airflow oscillations. Peak pressure trends and simulations suggest surge likelihood at ∼3.33 × 105 J enthalpy. In fluid dynamics, post-initial surge, a stall state ensues. Tip clearance vortices from spillage and backflow expand, merge, and fill the passage. Their pre-secondary surge breakdown elevates pipeline pressure, causing gas reflux and surge recurrence. Conclusively, this research enhances compressor secondary surge comprehension, offering support for design optimization and anti-surge strategies.

Vocal Instabilities in Untrained Female Singers.

This study aimed to identify voice instabilities across registration shifts produced by untrained female singers and describe them relative to changes in fundamental frequency, airflow, intensity, inferred adduction, and acoustic spectra. Multisignal descriptive study. Five untrained female singers sang up to 30 repetitions of octave scales. They first produced these octave scales "naturally," followed by productions that were either deliberately smooth or deliberately unsteady. With all types of scaleproductions, participants sang with both /α/ and /i/ vowels, at two different dynamic levels, and across both the upper and lower predetermined register transitions. Recorded scales were categorized into three groups (Smooth, Middle, Unsteady) based on researcher-based perceptual smoothness of the auditory signals. These groups allowed for determination of salient features of unsteadiness based on observations and analyses of the acoustic, airflow, intensity, and electroglottography (EGG) waveforms. A total of 13 different types of instabilities were observed. The number of instabilities within a single scale ranged from zero to fourteen. Most Smooth scales had zero to three instabilities, most Middle scales had four to six, and most Unsteady scales had six or more instabilities within the scale. More obvious instabilities, such as aphonic segments, were present only in Unsteady scales, while more subtle instabilities, such as those related to EGG signal changes, were common in all scale categories, including Smooth scales. This study revealed that untrained singers can sing smoothly throughout octave scales, and the primary unsteadiness variable was an aphonic segment and corresponding abrupt and large intensity reduction. Particular instabilities may be related to subtle aspects of register change and vocal control. Some objective measures appear to be more visually and numerically salient than auditorily perceived events relative to unsteadiness in the production of scales.

A fluidic device for continuous on-line inductive sensing of proteolytic cleavages.

Proteases, an important class of enzymes that cleave proteins and peptides, carry a wealth of potentially useful information. Devices to enable routine and cost effective measurement of their activity could find frequent use in clinical settings for medical diagnostics, as well as some industrial contexts such as detecting on-line biological contamination. In particular, devices that make use of readouts involving magnetic particles may offer distinct advantages for continuous sensing because material they release can be magnetically captured downstream and their readout is insensitive to optical properties of the sample. Bioassays based on giant magnetoresistance sensors that detect the binding or release of magnetic materials have been widely explored for these reasons, but they typically require expensive consumables. Here, we develop a simpler protease sensor based on inductive detection of particle release with pulsed magnetic fields, leveraging a design that incorporates both the pulse coil and gradiometer coils into a printed circuit board. Our fluidic chips are formed from casts of 3D printed molds, such that both the sensor and the consumable components could be relatively easy to mass produce. Using pulses ranging up to 10 s of mT, we show that our device has a limit of detection below 1 μg of iron and that its duty cycle can be varied to control temperature through Joule heating. By chemically functionalizing the glass surface of our fluidic chips with zwitterionic polymer and incorporating a PEG block co-polymer into the PDMS component, we are able to suppress the nonspecific binding of albumin by 7.8 times inside the chips. We demonstrate a layer-by-layer approach for covalently linking magnetic nanoparticles to the chips via cleavable peptide substrates. Finally, we observe the release of the magnetic particles from the chips under conditions of proteolytic cleavage and measure resulting changes in inductive signals, demonstrating a detection sensitivity for chymotrypsin in the hundreds of nM. The methods we establish here have the potential to aid progress toward sensors comprised of disposable fluidic chips measured by inexpensive detection devices that may one day facilitate ubiquitous protease activity monitoring.

Ultrasensitive and high selectivity detection of fibrin using Y-shaped DNA-homing peptide doped probe on localized surface plasmon resonance platform.

Localized surface plasmon resonance (LSPR) sensor has drawn continuous attention to application of the detection of antibody, protein, virus, and bacteria. However, natural recognition molecules, such as antibody, which possess some properties, including low thermal stability, complicated operation and high price, uncontrollability of length and size and a tendency to accumulate easily on the surface of chip to reduce the sensitive of method. Furthermore, common blocking agents are not suitable for development of novel biosensors. There is a significant demand for an innovative artificial probe that can meet the high recognition capabilities and ultrasensitive required by LSPR sensors. A LSPR sensor was developed for ultrasensitive detection of fibrin with a Y-shaped DNA-homing peptide doped probe. The Y-shaped probe, composed of three single stranded DNA (ssDNA), was immobilized on AuNPs chip. The two arms of Y-shaped probe were functionalized with homing peptides capable of recognizing fibrin. Additionally, in combination with the hybridization chain reaction, the growth of the arms facilitated enhanced functionalization with homing peptides to improve the sensitivity of method. Furthermore, ssDNA with a G-quadruplex structure acted as a novel blocking agent and was immobilized on the surface of the LSPR chip to minimize non-specific adsorption. Ultimately, remarkable changes in the LSPR signal were observed upon introduction of fibrin. Under optimized experimental conditions, the response of the LSPR biosensor followed a linear regression equation ΔLSPR=5420.53+395.14lgC (where C represents the concentration of fibrin in mol L-1), exhibiting a high linear correlation coefficient R=0.9979 and attaining a limit of detection of 1×10-14molL-1. It is believed that this work holds promising potential for the Y-shaped DNA-homing peptide doped probe, which takes advantage of the DNA structure with nanometer precision through programmable hybridization and the specific recognition of the homing peptide. Herein the developed LSPR biosensing platform demonstrated outstanding specificity and ultrasensitivity, rendering it suitable for early cancer screening.

Iron nanoparticle/carbon nanotube composite as oxidase-like nanozyme for visual analysis of total antioxidant capacity.

Total antioxidant capacity (TAC) is an important indicator for assessing the merit of natural plants and foods. Herein, a visual TAC assay is developed based on the oxidase-like activity of nitrogen-doped carbon nanotubes loaded with Fe nanoparticles (FeNPs@NCNT), which is prepared via high-temperature pyrolysis of metal-organic framework precursors and can catalyze the oxidation of colorless o-phenylenediamine (OPD) to colored 2,3-diaminophenazine (DAP). The addition of antioxidants (e.g., quercetin) impedes the formation of DAP, diminishing the color change, which can be analyzed via the RGB values obtained with a smartphone color-recognition APP, "Color Picker". The change of the optical signal can also be analyzed in the fluorescence mode. These two detection modes yield consistent TAC analysis of actual plant samples, in accord with results from the standard ABTS method. Results from this study highlight the unique potential of nanozymes in the development of effective TAC analysis platforms for natural plants and food.