Phase Values Research Articles

Comparison of ante- and postmortem ventricular wall thickness using echocardiography and autopsy findings

AbstractIn autopsy practice, the thickness of ventricular walls is one of the parameters used to identify cardiac hypertrophy. The presented study aimed to compare ante- and postmortem measurements of ventricular wall thickness, (i) to determine a postmortem standardized localization and dissection method for ventricular wall measurements, and (ii) to determine the ability of postmortem measurements in recognition of antemortem hypertrophy. A single-center prospective study was conducted at the Institute of Legal Medicine in Hamburg, Germany. Sixty hearts were dissected alternating by the inflow-outflow or short-axis method, and the ventricular walls were measured at different locations and compared with the echocardiographic values of the end-diastolic phase during life of these individuals. The results showed measurement differences between the autoptic and echocardiographic values—for the left ventricle between 3.3 and 5.2 mm, for the right ventricle between 0.2 and 1.1 mm, and for the septum between 1.3 and 1.4 mm. Diagnostic performance of recognizing antemortem hypertrophy with postmortem measurement was poor, except for measuring the right ventricle and septum with the short-axis method (area under the ROC curve of 0.72 and 0.82, respectively). According to the results, cardiac changes may occur postmortem and need to be considered when used for diagnosing cardiac pathology. The postmortem diagnosis of left or right ventricular hypertrophy should always be made in conjunction with other, particularly cardiac, autopsy findings. An autoptic diagnosis of hypertrophy solely by a ventricular wall thickness > 15 mm or > 5 mm alone is not sufficient.

Changes in Microstructure and Mechanical Properties of Goryeo Dynasty Bronze Vessels with Manufacturing Process

Bronze vessels are manufactured using casting and forging techniques, and various microstructures can be observed depending on the manufacturing process. In this study, we confirmed mechanical properties and microstructural evolution in the manufacturing process by observing the microstructures and composition analysis of 18 bronze vessels in the Goryeo Dynasty excavated from historical sites. The results show that 13 of the bronze vessels were manufactured using a Cu-Sn alloy with a Sn content of 20 to 24 wt%. The α phase and β(M) phase were observed, indicating that hot forging and quenching treatment were performed after casting. 3 bronze vessels were produced from a Cu-Sn-Pb alloy, and considering that the α phase and α+δ phase were observed, it could be seen that the process was completed by slow cooling after casting. The correlation between the type of bronze vessel and the manufacturing process has not been confirmed, except of ewer. It was confirmed that various microstructures were created depending on the manufacturing process and that the mechanical properties also changed. Bronze vessels composed of the α phase and α+δ phase due to the casting process had lower Vickers hardness values compared to bronze vessels that showed the quenched β(M) or γ phase. Electron backscatter diffraction (EBSD) phase analysis and kernel average misorientation (KAM) were performed using six bronze vessels composed of α and β(M) phases. The results showed that the factors affecting hardness were the ratio of the β(M) phase and the KAM value. However, it could not be confirmed to what extent the ratio of the β(M) phase and KAM value affected the improvement in mechanical properties.

Quantum Cournot model based on general entanglement operator

The properties of the Cournot model based on the most general entanglement operator containing quadratic expressions which is symmetric with respect to the exchange of players are considered. The degree of entanglement of games dependent on one and two squeezing parameters and their payoff values in Nash equilibrium are compared. The analysis showed that the relationship between the degree of entanglement of the initial state of the game and the payoff values in Nash equilibrium is ambiguous. The phase values included in the entanglement operator have a strong influence on the final outcome of the game. In a quantum duopoly based on the initial state of a game that depends on one squeezing parameter, the maximum possible payoff in Nash equilibrium cannot be reached when the value of the phase parameter is greater than zero, in contrast with a game that depends on two parameters.

Utilizing the Postvascular Phase of Contrast-Enhanced Ultrasound to Predict Breast Cancer Lymph Node Metastasis

Background and Objectives: To evaluate the value of the postvascular phase of contrast-enhanced ultrasound (CEUS) in differentiating between benign and metastatic lymph nodes (LNs) in patients with breast cancer (BC). Materials and Methods: This study retrospectively analyzed 96 suspicious LNs in the lymphatic drainage area of the breast from 90 patients with BC. All LNs were assessed by conventional ultrasound (US) and CEUS following intravenous Sonazoid injection. All LNs underwent puncture biopsy, and pathological results were obtained. The correlations between US and CEUS indicators of LNs and LN metastasis (LNM) were analyzed. Results: Of the 96 LNs, 66 were metastatic. Overall, 80.00% (24/30) of the benign LNs exhibited relative hyper-enhancement in the postvascular phase, whereas 96.97% (64/66) of the metastatic LNs exhibited relative hypo-enhancement (p < 0.001). This CEUS finding was highly predictive of metastasis, with a sensitivity of 96.97%, specificity of 80.00%, positive predictive value of 91.43%, negative predictive value of 92.31%, and accuracy of 91.67%. The mean postvascular phase intensity (MPI) was significantly lower for malignant (median MPI, 12 dB) than for benign (median MPI, 75 dB) LNs. The postvascular phase was more sensitive, specific, and accurate than conventional US or the vascular phase of CEUS for the diagnosis of LNM, with an area under the curve of 0.95 (95% confidence interval: 0.89–0.99). Conclusions: Qualitative and quantitative indicators of the postvascular phase of CEUS provide a reliable diagnostic approach to differentiate benign and metastatic LNs in patients with BC.

Spatially resolved plasma composition evolution in a solar flare – The effect of reconnection outflow

Context. Solar flares exhibit complex variations in elemental abundances compared to photospheric values. These abundance variations, characterized by the first ionization potential (FIP) bias, remain challenging to interpret. Aims. We aim to (1) examine the spatial and temporal evolution of coronal abundances in the X8.2 flare on 2017 September 10, and (2) provide a new scenario to interpret the often observed high FIP bias loop top, and provide further insight into differences between spatially resolved and Sun-as-a-star flare composition measurements. Methods. We analyzed 12 Hinode/Extreme-ultraviolet Imaging Spectrometer (EIS) raster scans spanning 3.5 hours, employing both Ca XIV 193.87 Å/Ar XIV 194.40 Å and Fe XVI 262.98 Å/S XIII 256.69 Å composition diagnostics to derive FIP bias values. We used the Markov Chain Monte Carlo (MCMC) differential emission measure (DEM) method to obtain the distribution of plasma temperatures, which forms the basis for the FIP bias calculations. Results. Both the Ca/Ar and Fe/S composition diagnostics consistently show that flare loop tops maintain high FIP bias values of > 2–6, with peak phase values exceeding 4, over the extended duration, while footpoints exhibit photospheric FIP bias of ∼1. The consistency between these two diagnostics forms the basis for our interpretation of the abundance variations. Conclusions. We propose that this variation arises from a combination of two distinct processes: high FIP bias plasma downflows from the plasma sheet confined to loop tops, and chromospheric evaporation filling the loop footpoints with low FIP bias plasma. Mixing between these two sources produces the observed gradient. Our observations show that the localized high FIP bias signature at loop tops is likely diluted by the bright footpoint emission in spatially averaged measurements. The spatially resolved spectroscopic observations enabled by EIS prove critical for revealing this complex abundance variation in loops. Furthermore, our observations show clear evidence that the origin of hot flare plasma in flaring loops consists of a combination of both directly heated plasma in the corona and from ablated chromospheric material; and our results provide valuable insights into the formation and composition of loop top brightenings, also known as EUV knots, which are a common feature at the tops of flare loops.

Parametrical synthesis of various radio devices with the set quantity of identical cascades of type «the nonlinear part – the mixed two-port network»

Background. Presence of possibility of analytical definition of a part of parametres of various radio devices, optimum by criterion of maintenance of preset values of modules and phases of transfer functions on necessary quantity of frequencies, considerably reduces time of numerical optimisation of other part of parametres by criterion of formation demanded frequency response and phase response in a strip of frequencies. Till now such problems dared concerning radio devices only with one cascade of type «a nonlinear part - the coordination the device» or «the coordination the device – a nonlinear part». In quality «the coordination devices were used the jet, resistive, complex or mixed two-port networks. The problem of multicascade radio devices with jet two-port networks is solved also. Change of basis for the coordination two-port networks and a place of inclusion of a nonlinear part leads to change of area of a physical realizability. Aim. Working out of algorithms of parametrical synthesis of radio devices with any quantity of identical and unequal cascades of type «a nonlinear part ‑the coordination the mixed two-port network» by criterion of maintenance of the set frequency characteristics. Nonlinear parts are presented in the form of a nonlinear element and parallel either consecutive on a current or pressure of a feedback. Methods. The theory of two-port networks, matrix algebra, a decomposition method, a method of synthesis of actuation microwave devices, numerical methods of optimisation. Results. In interests of achievement of the specified purpose systems of the algebraic equations are generated and solved. Models of optimum two-port networks in the form of mathematical expressions for definition of interrelations between elements of their classical matrix of transfer and for search of dependences of mixed of two-poles from frequency are received. It is shown, that at certain parities between quantity of cascades and values of resistance of a source of a signal and loading of the one-cascade radio device frequency characteristics of one-cascade and multicascade radio devices appear identical or similar. Such schemes are named by equivalent. Conclusion. The comparative analysis of theoretical results (frequency response and phase response radio devices, value of parametres), received by mathematical modelling in system MathCad, and the experimental results received by схемотехнического of modelling in systems OrCad and MicroCap, shows their satisfactory coincidence.

A Versatile Image Encryption Scheme Based on Optical Hologram Technology and Chess Rules

A novel versatile image encryption scheme about hologram technology and chess rules is proposed in this paper. This scheme can encrypt images by transferring them from the spatial domain to the frequency domain. First, the theory of computer-generated holograms is applied to record phase and amplitude features by imitating the optical hologram. The original image is transformed to a hologram and the phase values of the points in the image are recorded. Second, the parameters associated with the plaintext image are obtained by a Hash function and used as the initial values of the chaotic system, and then the pawns on the board are regarded as pixel points of the image, where the movement direction of the pawns is the movement direction of the pixel points of the image. The hologram is confused by combining the pawns’ movement rules with the chaotic sequences. Finally, the encrypted image is gained through a combination of the chaotic sequence and the selective diffusion method. The test results show that the scheme is able to resist various attacks and has good security performance in encryption.

Implementing the procedure of measurement phase difference of the model signals using a virtual laboratory practicum

As this virtual laboratory practicum, which is a tool for mastering theoretical principles and practical skills in digital signal processing, was developed, users (mainly students) were given the possibility to parameterize harmonic signals. It includes the determination of the number of samples, sampling rate, amplitudes, initial phases, and other characteristics necessary for accurate metrological measurements. This publication presents the structure of the virtual workshop and the mathematical model underlying it, with an emphasis on aspects of analyzing the procedures for measuring the phase difference of harmonic signal models using the Discrete Fourier Transform. Particular attention is focused on the phase correction algorithm, which is aimed at improving the accuracy of measurements of the phase difference of signals. The presented methodology describes in detail the measurement process, estimation of errors arising from limited measurement time due to non-synchronization, the influence of the initial phase values of signals, and shows how the synchronization process contributes to a significant increase in the accuracy of measuring informative parameters.

Measurement Verification of a Developed Strategy of Inrush Current Reduction for a Non-Loaded Three-Phase Dy Transformer

This article presents the measurement verification of a novel strategy for inrush current reduction in an unloaded three-phase Dy transformer. The strategy combines appropriate pre-magnetization of transformer cores with an original control switching system using initial phase values of the supply voltage as control variables. Measurements were recorded for primary voltages and currents as well as secondary voltages during transient states at start-up under no-load conditions. Various inrush scenarios were examined across the full angular spectrum of initial phase angles, both polarities, and in regard to different pre-magnetization current values. A detailed analysis of the inrush currents was performed using proprietary automated software based on the recorded data. A comparative study with a nonlinear mathematical model of the transformer was also conducted. Additionally, key technical aspects of the designed system for implementing the proposed pre-magnetization strategy with controlled voltage energization are discussed.

Determination of surface free energy and acido-basicity of MXene materials measured by inverse gas chromatography at infinite dilution

Since the seminal report of Ti3C2Tx in 2011, MXene has emerged as a subject of considerable interest among researchers, finding diverse applications spanning energy storage, catalysis, and coatings. Despite extensive studies on the physicochemical properties of MXene, a comprehensive understanding of its surface energetics, free from environmental influences or external substitutes, remains lacking. This study aims to fill this gap by employing the inverse gas chromatography (IGC) technique at infinite dilution to delineate the London dispersive and specific components, alongside the Lewis acid-base characters, of surface free energy in MXene materials, including MAX phase and MXene. Our findings reveal that the London dispersive surface energy values of MAX phase and MXene range from 59.3 to 80.2 mJ m−2 and 107.8–119.9 mJ m−2, respectively, across temperature ranges of 303–333 K and 393–423 K. The observed augmentation in surface energy for MXene is attributed to a higher density of non-polar surface groups and an enlarged interlayer spacing. Additionally, our analysis indicates significantly higher acceptor (KA) and donor (KD) parameters for MXene (0.97 and 1.97, respectively) compared to MAX phase (0.41 and 0.63, respectively), suggesting a preference for the Lewis acid-base character in both materials, with MXene exhibiting a more pronounced tendency. These findings offer crucial insights into the fundamental surface energetic characteristics underlying multiple physicochemical properties of MXene. This understanding facilitates the informed design of interface engineering strategies, advancing the exploration and advancement of MXene-based technologies across a broad spectrum of applications.

Fermion masses and mixings and g − 2 muon anomaly in a Q6 flavored 2HDM

We propose an extended 2HDM with Q6×Z4×Z2 symmetry that can successfully accommodate the SM fermion mass and mixing hierarchy. The tiny masses of the active neutrinos are generated from a type-I seesaw mechanism mediated by very heavy right-handed Majorana neutrinos. The model gives a natural explanation of the charged lepton mass hierarchy. Besides that, the experimental values of the physical observables of the neutrino sector: the neutrino mass squared splittings, the leptonic mixing angles and the leptonic Dirac CP violating phase, are also successfully reproduced for both normal and inverted neutrino mass hierarchies. We find a feasible range of values for the leptonic Dirac CP phase to be in the ranges δCP∈(305.90,348.70)∘ for normal ordering and δCP∈(308.00,348.00)∘ for inverted ordering, which is consistent with the 3σ experimentally allowed limits. The sum of neutrino masses is obtained as ∑mi∈(58.03,60.51) meV for normal ordering and ∑mi∈(98.07,101.40) meV for inverted ordering which are well consistent with all the recent limits. In addition, the obtained ranges for the effective neutrino masses are 〈mee〉∈(3.80,4.38) meV, mβ∈(8.53,9.34)meV for normal ordering and 〈mee〉∈(47.85,49.58) meV, mβ∈(48.39,50.09)meV for inverted ordering which are in agreement with the recent experimental bounds. For the quark sector, the derived results are also in agreement with the recent data on the quark masses and mixing angles. The model under consideration can also accommodate the muon anomalous magnetic moment.

Dual-energy CT late arterial phase iodine maps for the diagnosis of acute non-occlusive mesenteric ischemia.

To evaluate the diagnostic accuracy of dual-energy CT (DECT) iodine maps in comparison to conventional CT series for the assessment of non-occlusive mesenteric ischemia (NOMI). We evaluated data from 142 patients (72 men; 50.7%) who underwent DECT between 2018 and 2022, with surgically confirmed diagnosis of NOMI. One board-certified radiologist performed region of interest (ROI) measurements in bowel segments on late arterial (LA) and portal venous (PV) phase DECT iodine maps as well as LA conventional series, in both ischemic and non-ischemic bowel loops, using surgical reports as reference standard, and in a control group of 97 patients. Intra- and inter-reader agreement with a second board-certified radiologist was also evaluated. Receiver operating characteristic (ROC) curve analysis was performed to calculate the optimal threshold for discriminating ischemic from non-ischemic bowel segments. Subjective image rating of LA and PV iodine maps was performed. DECT-based iodine concentration (IC) measurements showed significant differences in LA phase iodine maps between ischemic (median:0.72; IQR 0.52-0.91mg/mL) and non-ischemic bowel loops (5.16; IQR 3.45-6.31mg/ml) (P <.0001). IC quantification on LA phase revealed an AUC of 0.966 for the assessment of acute bowel ischemia, significantly higher compared to both IC quantification based on PV phase (0.951) and attenuation values evaluated on LA conventional CT series (0.828). Excellent intra-observer and strong inter-observer agreements were observed for the quantification of iodine concentration. Conversely, weak inter-observer agreement was noted for conventional HU assessments. The optimal LA phase-based IC threshold for assessing bowel ischemia was 1.34mg/mL, yielding a sensitivity of 100% and specificity of 96.48%. Iodine maps based on LA phase significantly improve the diagnostic accuracy for the assessment of NOMI compared to conventional CT series and PV phase iodine maps.

Highly stable, controllable, and antibacterial nanocellulose-stabilized aroma emulsions via interfacial self-assembly strategy

The nanocellulose-stabilized aroma emulsions have the potential to replace surfactant-stabilized emulsions. However, the stability of aroma emulsions stabilized by nanocellulose still remains a challenging task. Herein, we developed a stable nanocellulose-stabilized aroma emulsion with controllable and antibacterial properties through cellulose nanocrystal (CNC) and NH2-PDMS-NH2 self-assembly at the oil-water interface. The stability, interfacial behavior, rheological and antibacterial properties of the emulsion were investigated. Our results reveal that the creaming index of the emulsions remained almost unchanged even after being stored for one week. The interfacial tension between the CNC aqueous phase and limonene decreased from 20.5 to 8.5 mN/m, as the addition of NH2-PDMS-NH2 (20 mg/mL). Notably, the interface tension (ranging from 3.5 to 11.1 mN/m) and the interfacial coverage rate of the CNC at the oil/water interface (ranging from 68.6 % to 97.5 %) could be tune by adjusting the pH value of the aqueous phase. The storage modulus and viscosity of the emulsions increased as the concentration of NH2-PDMS-NH2 increased. The aroma emulsion was highly stable under the conditions of 1.5 wt% CNC, 10 mg/mL NH2-PDMS-NH2, the oil/water ratio of 1/9, and the aqueous phase pH of 3. Moreover, these emulsions exhibited significant resistance to Escherichia coli and Staphylococcus aureus. Overall, this research provides a method to prepare a stable nanocellulose-based aroma emulsion, which could extend the application area of aroma emulsion.

Quantitative phase imaging verification in large field-of-view lensless holographic microscopy via two-photon 3D printing

Large field-of-view (FOV) microscopic imaging (over 100 mm2) with high lateral resolution (1–2 μm) plays a pivotal role in biomedicine and biophotonics, especially within the label-free regime. Lensless digital holographic microscopy (LDHM) is promising in this context but ensuring accurate quantitative phase imaging (QPI) in large FOV LDHM is challenging. While phantoms, 3D printed by two-photon polymerization (TPP), have facilitated testing small FOV lens-based QPI systems, an equivalent evaluation for lensless techniques remains elusive, compounded by issues such as twin-image and beam distortions, particularly towards the detector’s edges. Here, we propose an application of TPP over large area to examine phase consistency in LDHM. Our research involves fabricating widefield phase test targets with galvo and piezo scanning, scrutinizing them under single-shot twin-image corrupted conditions and multi-frame iterative twin-image minimization scenarios. By measuring the structures near the detector’s edges, we verified LDHM phase imaging errors across the entire FOV, with less than 12% phase value difference between areas. Our findings indicate that TPP, followed by LDHM and Linnik interferometry cross-verification, requires new design considerations for precise large-area photonic manufacturing. This research paves the way for quantitative benchmarking of large FOV lensless phase imaging, enhancing understanding and further development of LDHM technique.

Diagnostic value of three complete blood count abnormalities, hypereosinophilia, hyperlymphocytosis and basophilic lymphocytes, in DRESS.

The prevalence and kinetics of hypereosinophilia (HE), hyperlymphocytosis (HL), basophilic lymphocyte (BL), are misdescribed. We aimed to assess their diagnostic value in the acute phase of DRESS in a monocentric retrospective study. Among 60 patients, 47% had probable DRESS, and 53% definite DRESS. HE and HL were present in 62% and 27% of patients, respectively, with no link to DRESS severity. BL, found in 85% of blood smears, were associated with definite DRESS. BL detection, although not specific nor sufficient alone, appears to be the most sensitive hematological factor for diagnosing DRESS, especially when HE or HL is absent. Clinicians should ensure that a blood smear review is performed whenever a DRESS is suspected. A prospective study is needed to confirm these findings.

A Note on Related-Tweakey Impossible Differential Attacks

In this note we review the technique proposed at ToSC 2018 by Sadeghi et al. for attacks built upon several related-tweakey impossible differential trails. We show that the initial encryption queries are improper and lead the authors to misevaluate a filtering value in the key recovery phase. We identified 4 other papers (from Eurocrypt, DCC, and 2 from ToSC) that follow on the results of Sadeghi et al. and in three of them the flawed technique was reused. We thus present a careful analysis of these types of attacks and give generic complexity formulas similar to the ones proposed by Boura et al. at Asiacrypt 2014. We apply these to the aforementioned papers and provide patched versions of their attacks. The main consequence is an increase in the memory complexity. We show that in many cases (a notable exception being quantum impossible differentials) it is possible to recover the numeric time estimates of the flawed analysis, and in all cases we were able to build a correct attack reaching the same number of rounds.

12521 Electrical Impedance Myography And Muscle Health In Older Adults With Type 1 Diabetes

Abstract Disclosure: A. Fremaint: None. G. Jung: None. E. Yu: None. M. Bouxsein: None. Introduction: Recent studies indicate that individuals with Type 1 diabetes mellitus (T1D) develop skeletal muscle health impairments which might contribute to falls and explain their high fracture risk. A novel handheld Electrical Impedance Myography (EIM) device (mScan model 1301, Myolex) has been developed to assess muscle quality by calculating tissue impedance. We hypothesized that mScan could identify individuals with worse strength and body composition outcomes among older adults with and without T1D. Methods: We studied participants of the T1D Bone Health Connection (BEACON) Study who were aged 50+ and who had undergone EIM testing (n=63 T1D, n=50 non-diabetic controls). We analyzed EIM-derived phase angle [Phase = arctan(reactance/resistance)] at 100 kHz in 3 upper extremity muscles (biceps brachii, lateral deltoid, and wrist extensors), where lower phase values indicate poorer muscle quality. Correlations of EIM data were performed with grip strength measured by a handheld dynamometer and appendicular lean mass/height2 (ALM/ht2) and visceral adipose tissue (VAT) from whole-body DXA scans. Pearson’s correlations were used for all statistical analyses. Results: Mean age (63±7 years), sex (54% female), and BMI (26.5 kg/m2) were similar between T1D and control groups. Adults with T1D had a nonsignificant trend towards lower muscle quality at the biceps brachii than controls (8.9±5.4 vs 10.9 ±6.0 degrees, p=0.078). There were no differences between groups in phase angle for lateral deltoid nor wrist extensors. Higher muscle quality at the biceps brachii was associated with higher grip strength (r=0.28, p=0.005) in the full cohort as well as in the T1D group (r=0.40, p &amp;lt;0.001). In the full cohort, greater VAT was associated with lower muscle health at the biceps brachii (r = -0.34, p=0.003) and lateral deltoid (r = -0.23, p&amp;lt;0.014), with similar patterns in both T1D and controls. There were no correlations of muscle quality with ALM/ht2. Conclusion: Our data suggest that mScan holds promise for detection of skeletal muscle health impairments in older adults, including those with T1D, potentially aiding in the diagnosis and prevention of related falls and fractures. Further research is required to investigate the association between VAT and muscle health and to validate the effectiveness of mScan in T1D and other populations. Presentation: 6/3/2024

Experimental Study on the Impact of Sorption-Desorption on Nitrate Isotopes

Nitrate pollution is a global environmental problem, and mean nitrate levels have risen by an estimated 36% in global waterways since 1990. Tracing nitrate sources is important for water quality management, and nitrate isotopes (δ15N-NO3− and δ18O-NO3−) are commonly used for this purpose because of the different isotopic compositions of different sources. However, the impact of nitrate sorption on matrix and desorption from matrix on N and O isotopic composition of nitrate in liquid phase has not been well clarified. To explore the mechanism for the changes in nitrate concentration and isotopes in liquid phase during sorption and desorption, this study took a shale sample (enriched in clay minerals and commonly exposed in the Earth), conducted a series of laboratory experiments for nitrate sorption and desorption, and studied the impact of sorption and desorption on nitrate N and O isotopic composition in liquid phase. The results showed that the shale sample exhibited a rapid sorption and desorption rate for nitrate in the surface water samples, with the nitrate concentration in the solution decreasing from 14.3 mg/L to 4.1 mg/L within 5 min. The sorption data fit the Langmuir model better than that of the Freundlich model. The maximum possible sorption (Qmax) for the shale sample was estimated to be 46 μg/g. Preliminary laboratory experiments showed that changes in δ15N-NO3− values were not obvious, and changes in δ18O-NO3− values in liquid phase were minor during sorption and desorption of the shale sample, suggesting that nitrogen isotopic fractionation can be neglected, and the sorption of nitrate by the shale sample has a very limited impact on the distribution of nitrate isotopes in liquid phase. However, the impact of nitrate desorption on the nitrate isotopes in liquid phase depends on the isotopic composition of exchangeable nitrate in the solid phase, which may be related to antecedent water–rock interactions. This study provides important information for elucidating the evolution mechanism of nitrate and its isotopic compositions following sorption-desorption, and is conducive to revealing the nitrogen cycle law in the environment.

On the phase consistency of apical organ of Corti vibrations

Low-frequency hearing is critically important for speech and music perception. However, technical and anatomical limitations previously made it difficult to study the mechanics of the low-frequency parts of the cochlea, but this changed with the introduction of optical coherence tomography vibrometry. With this technique, sound-evoked vibration can be measured from the apex of a fully intact cochlea. Results of such measurements generated controversy because conventional traveling waves, the hallmark of which is longer group delay closer to the helicotrema, were absent within the apical 20% of the guinea pig cochlea (Burwood et al, Science Advances 8:eabq2773, 2022). The validity of this result was questioned, primarily because group delays were calculated from phase values averaged across many points within the organ of Corti. Here we show that variations in phase across the organ of Corti are minor and does not affect the group delay significantly. We also assess the precision of phase measurements with optical coherence tomography. An artificial target with reflectivity similar to the organ of Corti was used. These measurements revealed that a commonly used commercial optical coherence tomography system produces half-cycle errors in 1-5% of pixels, leading to a bimodal distribution of phase values. This problem can be easily addressed by using medians when computing averages, as was done by Burwood et al (2022). Hence, neither averaging across pixels nor technical factors can explain the apparent lack of conventional traveling waves at the apex of the guinea pig cochlea at low stimulus levels. The physiological mechanisms that operate at the apex apparently differ from other cochlear regions.

Comparing phase sensitive detection and Fourier analysis of modulation excitation spectroscopy data exemplified by Ambient Pressure X-ray Photoelectron Spectroscopy

Dynamic processes in catalysis are gaining increased attention and could very well be one of the next frontiers in surface science. One way to study such processes is to induce chemical changes on the surface for example by periodically adjusting the (electro)chemical potential in situ and identify the resulting spectral changes. Often this is referred to as Modulation Excitation Spectroscopy (MES). Using Ambient Pressure Photoelectron Spectroscopy data, we here discuss and compare the analysis of MES data using both Phase Sensitive Detection (PSD) and Fourier analysis. We discuss that PSD determines the component magnitude at a user-defined phase value while Fourier analysis provides the maximum oscillation amplitude and respective phase value of oscillating spectral features. We discuss advantages and disadvantages of the different analysis schemes and explore how the full time-evolution can be obtained.