Perturbation Measures Research Articles

Probing Noncovalent Interaction Strengths of Host-Guest Complexes Using Negative Ion Photoelectron Spectroscopy.

Noncovalent interactions (NCIs) are crucial for the formation and stability of host-guest complexes, which have wide-ranging implications across various fields, including biology, chemistry, materials science, pharmaceuticals, and environmental science. However, since NCIs are relatively weak and sensitive to bulk perturbation, direct and accurate measurement of their absolute strength has always been a significant challenge. This concept article aims to demonstrate the gas-phase electrospray ionization (ESI)-negative ion photoelectron spectroscopy (NIPES) as a direct and precise technique to measure the absolute interaction strength, probe nature of NCIs, and reveal the electronic structural information for host-guest complexes. Our recent studies in investigating various host-guest complexes that involve various types of NCIs such as anion-π, (di)hydrogen bonding, charge-separated ionic interactions, are overviewed. Finally, a summary and outlook are provided for this field.

Evidence-Based Recommendations for Tablet Recordings From the Bridge2AI-Voice Acoustic Experiments

BackgroundAs part of a larger goal to create best practices for voice data collection to fuel voice AI research, the objective of this study was to investigate the ability of readily available iOS and Android tablets with and without low-cost headset microphones to produce recordings and subsequent acoustic measures of voice comparable to “research quality” instrumentation. MethodsRecordings of 24 sustained vowel samples representing a wide range of typical and disordered voices were played via a head-and-torso model and recorded using a research quality standard microphone/preamplifier/audio interface. Acoustic measurements from the standard were compared to two popular tablets using their built-in microphones and with low-cost headset microphones at different distances from the mouth. ResultsVoice measurements obtained via tablets + headset microphones close to the mouth (2.5 and 5cm) strongly correlated (r’s > 0.90) with the research standard and resulted in no significant differences for measures of vocal frequency and perturbation. In contrast, voice measurements obtained using the tablets’ built-in microphones at typical reading distances (30 and 45cm) tended to show substantial variability in measurement, greater mean differences in voice measurements, and relatively poorer correlations vs. the standard. ConclusionFindings from this study support preliminary recommendations from the Bridge2AI-Voice Consortium recommending the use of smartphones paired with low-cost headset microphones as adequate methods of recording for large-scale voice data collection from a variety of clinical and non-clinical settings. Compared to recording using a tablet directly, a headset microphone controls for recording distance and reduces the effects of background noise, resulting in decreased variability in recording quality. Data Availability StatementData supporting the results reported in this article may be obtained upon request from the contact author.

Merging Mesoscale Magnetotail Features and Ground B‐Field Perturbation Network Connectivity During Substorm Activity

AbstractThe connection between the magnetosphere and ionosphere is particularly dynamic during substorms. Mesoscale features in the magnetotail are consistent with substorm activity, including magnetic reconnection in the tail, flow channels, and particle injections. Observations of substorm related phenomena can be made using energetic neutral atom (ENA) imagers, in situ satellite measurements, and ground based magnetic field perturbation measurements. Analysis of the 10 October 2014 isolated substorm event is presented. Comparison of the spatial and temporal dynamics of the features seen in equatorial maps generated from ENA data are made with inner magnetosphere in situ measurements and ionospheric features with network analysis of the SuperMAG data. An MHD simulation of the event using OpenGGCM is also compared with the data.

Emotion perception through the nose: how olfactory emotional cues modulate the perception of neutral facial expressions in affective disorders

Humans can decode emotional states from the body odors of the conspecifics and this type of emotional communication is particularly relevant in conditions in which social interactions are impaired, as in depression and social anxiety. The present study aimed to explore how body odors collected in happiness and fearful conditions modulate the subjective ratings, the psychophysiological response and the neural processing of neutral faces in individuals with depressive symptoms, social anxiety symptoms, and healthy controls (N = 22 per group). To this aim, electrocardiogram (ECG) and HD-EEG were recorded continuously. Heart Rate Variability (HRV) was extracted from the ECG as a measure of vagal tone, event-related potentials (ERPs) and event-related spectral perturbations (ERPSs) were extracted from the EEG. The results revealed that the HRV increased during the fear and happiness body odors conditions compared to clean air, but no group differences emerged. For ERPs data, repeated measure ANOVA did not show any significant effects. However, the ERPSs analyses revealed a late increase in delta power and a reduced beta power both at an early and a late stage of stimulus processing in response to the neutral faces presented with the emotional body odors, regardless of the presence of depressive or social anxiety symptoms. The current research offers new insights, demonstrating that emotional chemosignals serve as potent environmental cues. This represents a substantial advancement in comprehending the impact of emotional chemosignals in both individuals with and without affective disorders.

First measurements of wind-turbine perturbations of fair-weather electric fields

Wind turbines have been shown to develop corona at blade tips due to the presence of the fair-weather electric field, but up to now there have been no published investigations of how the presence of a wind turbine perturbs the fair-weather field as measured on the ground near the turbine. Such data may be useful to evaluate the integrity of turbine lightning protection systems. We present the first such published measurements in this paper. Our model predicts measurable periodic variations, and our experimental measurements show a peak-to-peak perturbation up to about 7 V m−1 in a nominal 100 V m−1 fair-weather field as measured on the ground under the moving turbine's blades. Smaller perturbations are detectable at greater distances.

On the criteria of a measure of non-strict cosingularity in the description of spectral properties of operator matrix

Abstract In this paper, we are interested to formulate new assumptions on the entries of an unbounded 3 × 3 3\times 3 block operator matrix defined with a maximal domain on the product of Banach spaces guaranteeing its corresponding Frobenius–Schur formula. Our approach allows us to derive some original stability results intervening in the theory of perturbed lower semi-Fredholm operators involving the concept of a measure of non-strict cosingularity perturbation. A new technique is presented to investigate the Weidmann and defect essential spectra of the closure of such model of operator matrix via new criterion of perturbation.

Enhanced perturbation measurement range chirped pulse ϕ-OTDR for distributed static measurements using feedback frequency-shift compensation technology

Chirped-pulse phase-sensitive optical time-domain reflectometry (CP-ϕOTDR) is a newly developed distributed optical fiber sensing (DOFS) technology that can measure physical quantities across the length of optical fiber. The measurement of perturbations as strain or temperature changes is performed by comparing the time domain trace of Rayleigh backscattered (RBS) light with a reference trace. However, large strain or temperature fluctuations or laser frequency noises necessitate frequent updates of the reference, and short-term change measurements must be integrated to obtain absolute strain or temperature, which introduces a 1/f noise component due to the combination of noise with each cumulative change. In this study, we propose a novel CP-ϕOTDR system based on frequency-shift compensation (FSC) technology. This system utilizes real-time feedback control of the central frequency of the incident laser to compensate for time domain trace distortion caused by large perturbations. It overcomes the limitations associated with the total chirp bandwidth and eliminates the 1/f noise component by obviating the need for frequent updates of the reference trace. The measuring range for perturbations is only limited to the wavelength range supported by the integrated optical devices, typically on the order of nanometers, corresponding to at least tens of Kelvin in temperature fluctuations or hundreds of micro-strains. To validate the effectiveness, we conducted a temperature measurement experiment involving a 1 K variation, which is about 90 times the maximum measurable perturbation that the original CP-ϕOTDR system can demodulate with the reference unchanged. The results demonstrate that the FSC method significantly expands the perturbation measurement range of the CP-ϕOTDR system.

Effect of Face Masks on Voice Quality Associated with Young and Older Chinese Adult Speakers

ObjectivesFace masks have become important after the pandemic, but the change in voice when wearing a face mask is still unclear. The study investigated the effect of face masks on the acoustic and perceptual characteristics of voice quality associated with young and older Chinese adults. MethodsVoice samples of the sustained vowel /a/ and continuous speech produced by 44 older and 61 young adults with and without an ASTM level-3 surgical face mask were recorded and analyzed. Perceptual and acoustic parameters including mean fundamental frequency (F0) and intensity, perturbation measures (jitter and shimmer), harmonic-to-noise ratio (HNR), smoothed cepstral peak prominence (CPPs), and long-term average spectrum (LTAS) measures were obtained and compared. ResultsWhen comparing masked to unmasked voices, for both male and female speakers, F0 and intensity showed no significant changes, except for F0 of continuous speech, which increased significantly. Meanwhile, perturbation measures including jitter and shimmer were reduced, HNR and CPPs were increased, and LTAS measures encompass low frequency mean spectral energy (MSE), high frequency MSE, and spectral tilt (ST) were different. For perceptual measures, the overall grade of dysphonia, and roughness were reduced, except for the breathiness among older male speakers, while the other vocal qualities were not changed. Between young and older speakers, significant differences in shimmer, CPPs, and perceived breathiness among male speakers, and low frequency MSE among female speakers were found. ConclusionWearing a surgical mask appeared to change the perceived voice quality. This is supported by the change in perturbation and LTAS measures, and HNR and CPPs values. In addition, some differences between young and older male adults were observed. Communication effectiveness may be affected when wearing surgical masks due to changes in voice quality. Additionally, clinicians need to exercise caution in evaluating the voice quality of clients when wearing face masks.

NMR chemical shift assignment of Drosophila odorant binding protein 44a in complex with 8(Z)-eicosenoic acid

The odorant binding protein, OBP44a is one of the most abundant proteins expressed in the brain of the developing fruit fly Drosophila melanogaster. Its cellular function has not yet been determined. The OBP family of proteins is well established to recognize hydrophobic molecules. In this study, NMR is employed to structurally characterize OBP44a. NMR chemical shift perturbation measurements confirm that OBP44a binds to fatty acids. Complete assignments of the backbone chemical shifts and secondary chemical shift analysis demonstrate that the apo state of OBP44a is comprised of six α-helices. Upon binding 8(Z)-eicosenoic acid (8(Z)-C20:1), the OBP44a C-terminal region undergoes a conformational change, from unstructured to α-helical. In addition to C-terminal restructuring upon ligand binding, some hydrophobic residues show dramatic chemical shift changes. Surprisingly, several charged residues are also strongly affected by lipid binding. Some of these residues could represent key structural features that OBP44a relies on to perform its cellular function. The NMR chemical shift assignment is the first step towards characterizing the structure of OBP44a and how specific residues might play a role in lipid binding and release. This information will be important in deciphering the biological function of OBP44a during fly brain development.

Modeling urban traffic volume incorporating driver stochasticity and traffic correlation with waveguide-based quantum walk

Urban traffic involves two stochastic factors, complicating accurate modeling: (1) Driver stochasticity, arising from driver heterogeneity and random environment perturbations, introduces unpredictable fluctuations in urban traffic volume. (2) Traffic correlation, referring to the interaction in traffic states across different regions. This paper proposes a waveguide-based quantum walk urban traffic volume model (UTVDC-QW), incorporating driver stochasticity and traffic correlation. The model uses waveguide arrays to map urban traffic networks, incorporates random environment perturbations via noise, and traffic correlation via waveguide coupling. UTVDC-QW develops measures of environment perturbations and traffic correlations. Experiments with Chengdu traffic datasets demonstrate that UTVDC-QW improves the simulation accuracy compared to reference models. In addition, the model reveals the characteristics of environment perturbations and traffic correlation in the study area. Overall, this study effectively incorporates driver stochasticity and traffic correlation by waveguide-based quantum walk, is a pioneering attempt to apply quantum computing to urban traffic modeling.

Nonlinear Dynamic Analysis and Perturbation Measurement Used for Discriminating Pathological Voices and Their Correlations With Perceptual Evaluation

1. To investigate the discriminatory and diagnostic power of nonlinear dynamic analysis measures concerning voices from normal, benign, and malignant voice disorders. 2. To study the correlations of nonlinear dynamic analysis measures with perceptual ratings to evaluate the reliability of the objective acoustic analysis in predicting severity of voice. The perturbation analysis metrics used were Jitter%, Shimmer%, and signal-to-noise ratio. The nonlinear dynamic analysis metrics used were spectrum convergence ratio (SCR), nonlinear energy difference ratio (NEDR), and rate of divergence (ROD). Subjects were enrolled and divided into three groups based on laryngeal pathology: normal, benign, and malignant. Vowel sound and reading samples were recorded. Perceptual evaluation was applied to these voice samples to investigate correlations between metrics and auditory perception. Each metric was capable of discriminating laryngeal pathology, except for SCR in the case of distinguishing between benign and malignant pathologies. Perturbation analysis parameters had a moderate ability to differentiate between normal and benign pathologies, but were unable to characterize malignant pathologies for certain diseases, such as Reinke's edema. All metrics significantly correlated with perceptual G scores. Nonlinear dynamic analysis was superior when applied to cases of severe dysphonia, where linear metrics such as Jitter% and Shimmer% tended to lose utility. NEDR and ROD were successful at differentiating between the different pathologies, whereas SCR could not discriminate between the benign and malignant groups. Perturbation and nonlinear dynamic analyses are comparable in their discriminating power with respect to normal and benign voices, and normal and malignant voices. The nonlinear dynamic analysis metrics NEDR and ROD may be superior in clinical settings with respect to discriminating voice pathology ranging from mild pathological voice to severe dysphonia, and with respect to discriminating benign and malignant voice. SCR was found unable to discriminate pathological voices.

Experimental study of core MHD behavior and a novel algorithm for rational surface detection based on profile reflectometry in EAST

Microwave reflectometry is a powerful diagnostic that can measure the density profile and localized turbulence with high spatial and temporal resolution and will be used in ITER, so understanding the influence of plasma perturbations on the reflect signal is important. The characteristics of the reflect signal from profile reflectometry, the time-of-flight (TOF) signal associated with the MHD instabilities, are investigated in EAST. Using a 1D full-wave simulation code by the Finite-DifferenceTime-Domain (FDTD) method, it is well validated that the local density flattening could induce the discontinuity of the simulated TOF signal and an obvious change of reflect amplitude. Experimental TOF signals under different types of MHD instabilities (sawtooth, sawtooth precursors and tearing mode) are studied in detail and show agreement with the simulation. Two new improved algorithms for detecting and localizing the radial positions of the low-order rational surface, the cross-correlation and gradient threshold (CGT) method and the 2D convolutional neural network approach (CNN) are presented for the first time. It is concluded that TOF signal analysis from profile reflectometry can provide a straightforward and localized measurement of the plasma perturbation from the edge to the core simultaneously and may be a complement or correction to the q-profile control, which will be beneficial for the advanced tokamak operation.

Biochemical and cellular characterization of the CISD3 protein: Molecular bases of cluster release and destabilizing effects of nitric oxide

The NEET proteins, an important family of iron-sulfur (Fe-S) proteins, have generated a strong interest due to their involvement in diverse diseases such as cancer, diabetes, and neurodegenerative disorders. Among the human NEET proteins, CISD3 has been the least studied, and its functional role is still largely unknown. We have investigated the biochemical features of CISD3 at the atomic and in cellulo levels upon challenge with different stress conditions i.e., iron deficiency, exposure to hydrogen peroxide, and nitric oxide. The redox and cellular stability properties of the protein agree on a predominance of reduced form of CISD3 in the cells. Upon the addition of iron chelators, CISD3 loses its Fe-S clusters and becomes unstructured, and its cellular level drastically decreases. Chemical shift perturbation measurements suggest that, upon cluster oxidation, the protein undergoes a conformational change at the C-terminal CDGSH domain, which determines the instability of the oxidized state. This redox-associated conformational change may be the source of cooperative electron transfer via the two [Fe2S2] clusters in CISD3, which displays a single sharp voltammetric signal at-31mV versus SHE. Oxidized CISD3 is particularly sensitive to the presence of hydrogen peroxide invitro, whereas only the reduced form is able to bind nitric oxide. Paramagnetic NMR provides clear evidence that, upon NO binding, the cluster is disassembled but iron ions are still bound to the protein. Accordingly, in cellulo CISD3 is unaffected by oxidative stress induced by hydrogen peroxide but it becomes highly unstable in response to nitric oxide treatment.

Pseudo-Drag-Free System Simulation for Bepicolombo Radio Science Using Accelerometer Data

The Mercury Orbiter Radio Science Experiment onboard the European Space Agency/Japan Aerospace Exploration Agency (JAXA) BepiColombo mission aims at determining the gravity field and the rotational state of the planet to provide insight into its internal structure and at performing tests of general relativity. The experiment will rely on accurate radiometric data provided by the onboard Ka-band transponder and on measurements of the nonconservative perturbations acting on the spacecraft, provided by the Italian Spring Accelerometer. This paper presents a software implementation of a pseudo-drag-free system which includes the accelerometer measurements in the orbit determination process. Numerical simulations focus on the identification of a suitable calibration strategy to fulfill the experiment goals pertaining to geodesy and geophysics. The achievement of the expected scientific results will depend meaningfully on the quality of the accelerometer data. Perturbative analysis aided in the identification of a calibration strategy for the accelerometer data processing that allows obtaining an unbiased solution and compensating for accelerometer errors.

Laser interferometric detection of heat release rate perturbation field of acoustically perturbed laminar premixed flames

Laser interferometry, which was originally used to measure density perturbation, has been previously used to determine the heat release rate perturbation, which is a key factor in the analysis of combustion instability. However, its spatial accuracy is still unsatisfied. In the present work, an improved fringe Fourier analysis method is proposed to process the results obtained from the laser interferometry measurement, aiming to accurately determine the spatial distribution of flame heat release rate perturbation. The measurement of heat release rate perturbation was performed on a acoustic perturbed laminar premixed flame, with the burner outlet diameter of 8 mm. Interference patterns generated by two laser beams with a diameter of 70 mm were recorded at a frame rate of 6000 Hz. A spatial dependent fringe processing method, referred as the improved fringe Fourier analysis, was developed to demodulate the interference phase from the fringe patterns. The proper orthogonal decomposition analysis was performed on these results to analyze the component of interference signals. Validation of the present technique was conducted by comparing the heat release rate perturbation field resulting from the laser interferometric technique to those from the CH* chemiluminescence from the flame. Comparisons were performed both for the global and local values, and the low-frequency natural oscillation effects were analyzed. Finally, a refraction correction method based on background-oriented Schlieren is proposed to compensate the beam deflection caused by flame.

On the Fourier asymptotics of absolutely continuous measures with power-law singularities

We prove sharp estimates on the time-average behavior of the squared absolute value of the Fourier transform of some absolutely continuous measures that may have power-law singularities, in the sense that their Radon–Nikodym derivatives diverge with a power-law order. We also discuss an application to spectral measures of finite-rank perturbations of the discrete Laplacian.

A Systematic Review of Speech-Language Pathology Interventions for Presbyphonia Using the Rehabilitation Treatment Specification System

BackgroundThe prevalence of voice disorders for people over the age of 65 is 4× higher than for the population at large. The most common cause of dysphonia in this group is presbyphonia, the preferred first-line treatment for which is voice therapy with a speech-language pathologist. This systematic review seeks to identify how voice therapy affects multidimensional voice outcomes in people with presbyphonia. MethodsA systematic search of CINAHL, Embase, Emcare, MEDLINE and Google Scholar was undertaken in March 2023. Comparative and non-comparative studies of voice therapy in participants over 50 years with presbyphonia were considered for inclusion. No limitations were placed on date or language of publication. Study quality and risk of bias were assessed with the Cochrane Risk of Bias 2 (RoB 2) tool and the Methodological Index for Non-Randomized Studies (MINORS). Subgroup analysis was used to compare studies based on participant sex, intervention duration, study design and intervention content. Interventions were specified using the Rehabilitation Treatment Specification System (RTSS) employing a consensus methodology among reviewers. Results were synthesized utilizing metanalysis when outcomes were adequately specified, and narrative analysis when they were not. Results23 studies were included with 1,050 subjects (mean age: 72.5 ± 8.6; 51% female). The most reported intervention was Vocal Function Exercises (VFEs). Per the RTSS, 14 interventions employed a predominantly Organ Functions approach and the 14 remaining interventions employed a Skills & Habits approach. Metanalysis confirmed post-therapy improvement in patient-related outcome measures (PROMs) of 0.93 standard mean difference (p<0.00001, 95% CI: 0.70-1.17); studies with predominantly males and with longer treatment periods were associated with larger improvements, while RCTs reported more modest improvements. Metanalysis also identified a mean post-therapy increase in maximum phonation time (MPT) of 5.37 seconds (p<0.00001, 95% CI: 3.52-7.22). Treatments with an Organ Functions focus resulted in greater gains in MPT than those with a Skills & Habits focus (7.52 s vs. 2.90 s). Finally, metanalysis identified reductions in acoustic perturbation measures (jitter: 0.62%, p<0.001, 95% CI: 0.26-0.97%; shimmer 1.05%, p<0.00001, 95% CI: 0.67-1.44%). Narrative synthesis further identified improvement in auditory-perceptual voice quality in all active treatment groups as well as improved glottal function in most studies which reported this. ConclusionsDespite the uncertainty around internal validity introduced by the inclusion of a wide range of study designs, there is convincing evidence that voice therapy for presbyphonia results in significant improvement in patient-reported, aerodynamic, acoustic, and expert-rated voice outcomes. Treatments with an Organ Functions focus may better address the underlying physiological deficits of presbyphonia, although future comparative studies with multidimensional voice assessment are warranted.

In situ measurements of perturbations to stratospheric aerosol and modeled ozone and radiative impacts following the 2021 La Soufrière eruption

Abstract. Stratospheric aerosols play important roles in Earth's radiative budget and in heterogeneous chemistry. Volcanic eruptions modulate the stratospheric aerosol layer by injecting particles and particle precursors like sulfur dioxide (SO2) into the stratosphere. Beginning on 9 April 2021, La Soufrière erupted, injecting SO2 into the tropical upper troposphere and lower stratosphere, yielding a peak SO2 loading of 0.3–0.4 Tg. The resulting volcanic aerosol plumes dispersed predominately over the Northern Hemisphere (NH), as indicated by the CALIOP/CALIPSO satellite observations and model simulations. From June to August 2021 and May to July 2022, the NASA ER-2 high-altitude aircraft extensively sampled the stratospheric aerosol layer over the continental United States during the Dynamics and Chemistry of the Summer Stratosphere (DCOTSS) mission. These in situ aerosol measurements provide detailed insights into the number concentration, size distribution, and spatiotemporal variations of particles within volcanic plumes. Notably, aerosol surface area density and number density in 2021 were enhanced by a factor of 2–4 between 380–500 K potential temperature compared to the 2022 DCOTSS observations, which were minimally influenced by volcanic activity. Within the volcanic plume, the observed aerosol number density exhibited significant meridional and zonal variations, while the mode and shape of aerosol size distributions did not vary. The La Soufrière eruption led to an increase in the number concentration of small particles (&lt;400 nm), resulting in a smaller aerosol effective diameter during the summer of 2021 compared to the baseline conditions in the summer of 2022, as observed in regular ER-2 profiles over Salina, Kansas. A similar reduction in aerosol effective diameter was not observed in ER-2 profiles over Palmdale, California, possibly due to the values that were already smaller in that region during the limited sampling period in 2022. Additionally, we modeled the eruption with the SOCOL-AERv2 aerosol–chemistry–climate model. The modeled aerosol enhancement aligned well with DCOTSS observations, although the direct comparison was complicated by issues related to the model's background aerosol burden. This study indicates that the La Soufrière eruption contributed approximately 0.6 % to Arctic and Antarctic ozone column depletion in both 2021 and 2022, which is well within the range of natural variability. The modeled top-of-atmosphere 1-year global average radiative forcing was −0.08 W m−2 clear-sky and −0.04 W m−2 all-sky. The radiative effects were concentrated in the tropics and NH midlatitudes and diminished to near-baseline levels after 1 year.

Towards automated stochastic Grey-Box Model Calibration for Heat Transfer Coefficient Inference

An accurate on-site measurement of the intrinsic thermal performance of the building envelope is a strong leverage to promote quality management and energy performance contracting. The building sector expects on-site measurements of the Heat Transfer Coefficient to be as short as possible and highly accurate. Perturbation measurement methods analysed by RC models have been shown to be promising with accurate results within 2 days. However, stochastic RC model calibration is highly dependent on expert knowledge. In particular, model initialisation jeopardises the calibration success if not carefully chosen a priori and all the more so with second or higher order models. This paper proposes and assesses a novel automated initialisation procedure for RC models. After having brought to light that the capacitance initialisation is critical to the calibration success, the paper shows how first-order models are almost always highly identifiable. The first-order model estimated parameters then serve as initial values for all second and higher order models. This novel procedure is in 78 % of the 156 cases tested better than or similar to expert knowledge initialisation. The results are very encouraging and suggest a successful integration in a global RC model calibration and selection workflow for a fully automated process.

Hyaluronan-arginine enhanced and dynamic interaction emerges from distinctive molecular signature due to electrostatics and side-chain specificity

Hyaluronan is a natural carbohydrate polymer with a negative charge that fosters gel-like conditions crucial for its cellular functions and industrial applications. As a recognized ligand for proteins, understanding their mutual interactions provides solid ground to tune hyaluronan's gel properties using biocompatible peptides. This work employs NMR and molecular dynamics simulations to identify molecular motifs relevant to hyaluronan–peptide interactions using arginine, lysine, and glycine oligopeptides. Arginine-rich peptides exhibit the strongest binding to hyaluronan according to chemical shift perturbation measurements, followed distantly by the similarly charged lysine. This difference highlights the significance of electrostatics and the peculiarities of the guanidinium side chain in arginine, capable of non-polar interactions that further stabilize the binding. Additional nuclear Overhauser effect measurements do not show stable interaction partners, precluding strong and well-defined complexes. Finally, molecular simulations support our findings and show an extended but significant interaction region, especially for arginine, responsible for the observed enhanced binding, which can also promote cross-linking of hyaluronan polymers. Our findings pave the way for optimizing biocompatible peptides to alter hyaluronan gels' properties efficiently and also explain why hyaluronan–protein interaction typically involves positively charged arginine-rich regions also capable of forming hydrogen bonds and non-polar interactions.