Spectral Analysis Research Articles

Abstract PO2-18-11: Short-term Pre-OPerative Durvalumab (MEDI 4736) in early small triple negative breast cancer patients (POP-Durva)

Abstract Background: Immune checkpoint inhibitors (ICIs) are one of the major therapeutic advancements in cancer treatment. Anti-programmed cell death protein 1 (Anti-PD1)/PD-L1 ICIs have improved progression-free survival in patients with metastatic triple negative breast cancer (TNBC) and pathologic complete response (pCR) and event-free survival in patients with early TNBC. Nevertheless, some patients treated with anti-PD(L)1 ICIs experience recurrence or do not achieve sustained clinical benefit. In addition, very interesting data show the existence of a subgroup of patients with exceptional tumour responses to monotherapy with anti-PD(L)1 ICIs. These exceptional responses are observed in various tumour types, such as colorectal or breast cancer. Although in colorectal cancer, the determinants for this extreme sensitivity to immunotherapy treatment are identified (existence of MSI) in breast cancer, this is not the case. There is still a lack of knowledge about predictive biomarkers and mechanisms of action for ICIs. Trial Design: POP-Durva (NCT05215106) is a prospective, one-arm-only study aiming at determining the pCR rate after two administrations of Durvalumab monotherapy in patients with stage I TNBC. This window-of-opportunity study will recruit 195 consecutive cases of stage I TNBC (ER < 1%, PR < 1%, HER2 negative) and TILs≥5%, eligible for short-term treatment with durvalumab. Study treatment consists of two administrations of intravenous Durvalumab monotherapy, 10mg/kg, at two weeks intervals. After study treatment, patients will receive a standard treatment strategy (surgery or neoadjuvant systemic treatment) as per physician choice. The primary endpoint is the pCR rate after treatment with Durvalumab, defined as the absence of invasive disease in the breast and negative axillary nodes (ypT0/yTis ypN0). Assessment of the primary endpoint will be performed at the surgery or at the biopsy at the end of treatment) for patients undergoing neoadjuvant treatment. For patients in whom neo-adjuvant therapy is the first standard treatment strategy (i.e. after study treatment) a breast ultrasound-guided biopsy is mandatory at the end of the treatment visit. If the biopsy-proven residual disease is demonstrated, patients can receive standard neoadjuvant therapy at the discretion of the treating investigator. Patients with biopsy-proven residual disease will be considered as having no pCR. Those with a complete response may proceed directly to surgery. The expected pCR rate with Durvalumab monotherapy is 20%. The sample size of 195 patients will allow us to estimate this expected pCR rate with a 95% confidence interval of a precision of 6.2%. Secondary objectives are objective response rate and safety. Exploratory objectives are to: a. describe immune cell dynamics associated with exceptional responses to ICI (using spectral cytometry analysis), b. describe somatic genetic contributions to the determination of immune responsiveness (using whole exome sequencing (WES) and in a subset of patient's single-cell RNA-seq), c. characterize tumour cells – immune cells' interaction/spatial distribution(using imaging mass cytometry), d. explore the association between gut microbiome composition/signatures predictive of response to ICI (using 16s rRNA sequencing) and e. identify predictive tissue/blood-based biomarkers of response and to anti-PD(L)1 ICIs therapy. A total of two dedicated FFPE samples and two fresh biopsies will be collected at the time of inclusion and at the end of treatment biopsy or on the surgical specimen. In addition, we will collect stool samples pre and at the completion of all Durvalumab treatments and blood samples at the time of inclusion, during treatment (before each Durvalumab administration) and at the end of treatment for serum and plasma extraction and whole blood to serve as a control for WES. Citation Format: Joana Mourato Ribeiro, Isabelle Pic, Quentin Blampey, Elie Rassy, Nusaibah Ibrahimi, Laura Salabert, Olivier Trédan, Monica Arnedos, Semih Dogan, Kamar Serhal Serhal, Clementine Mahaut, Alessandro Viansone, Salim Laghouati, Barbara Pistilli, Charles-Antoine Dutertre, Magali Lacroix-Triki, Jean-Yves Scoazec, Lisa Derosa, Laurence Zitvogel, Corinne Balleyguier, Nadege Bercovici, Paul-Henry Cournede, Stefan Michiels, Fabrice André. Short-term Pre-OPerative Durvalumab (MEDI 4736) in early small triple negative breast cancer patients (POP-Durva) [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-18-11.

Synthesis, Antimicrobial Assessment of Chalcones and their Pyrimidine Derivatives

The aim of the study was to transform chalcones synthesized to their respective pyrimidine derivatives which was successful. The synthesized compounds were subjected to antimicrobial assay against bacteria and fungi organisms screened, however sample ZB had inhibitory effect against bacterial strains. Sample ZB is active against S. aureus and E. coli with an MIC of 5 and 1 mg/mL with a zone of inhibition 11 and 23 mm respectively. When compared to sample B had activity against E. coli with a minimum inhibitory concentration of 0.1 mg/mL and zone of inhibition of 20 mm. Modification of 4-(2-hydroxyphenyl)-6-(2,3,4-trimethoxyphenyl)pyrimidin-2-one to pyrimidin-2-one increases spectrum of activity against gram positive bacterial S. aureus. Sample A inhibits B. subtilis and P. marneffei with an MIC of 10 mg/mL with a zone of inhibition of 14 mm and 20 mm respectively. Transformation of Sample A to 2-aminopyrimidine drastically abolish the antibacterial and antifungal effect. Sample ZA is inactive against bacteria and fungi organisms, when compared to ZB which inhibits S. aureus and E. coli. The spectral analysis revealed that the samples are in line with literature and had a melting point (100-103oC and 115-117oC) for sample ZA and ZB respectively. The starting materials had a melting point (55-57oC and 95-100oC) for Sample A and B respectively.

Dark matter search in the Perseus cluster with simultaneous analysis of Hitomi and Suzaku data

Abstract The reported detection of a 3.5 keV emission line in the Perseus cluster, possibly originating from dark matter decay, is still under scrutiny. Despite extensive observations, the detection has not yet been confirmed, and its origin remains a topic of active debate. Most of the previous searches relied on spectroscopy with X-ray charge-coupled devices, such as the X-ray Imaging Spectrometer on Suzaku. Although this provided a large amount of observational data, it only offered moderate spectral resolution. The X-ray astronomy satellite Hitomi offers new results using its high-resolution X-ray spectrometer (Soft X-ray Spectrometer). However, the data gathered were somewhat limited in terms of statistics. In this work, we present the results of a new spectral analysis of the Perseus cluster that combines the spectra from the XIS and SXS, along with the Soft X-ray Imager on Hitomi, thereby complementing each other’s capability. Our search was conducted for a line emission or absorption in the energy range of 2.6–5.9 keV assuming the Navarro–Frenk–White mass distribution with a concentration parameter of 5.0 and virial radius, r200, of 1.79 Mpc. We also considered the instrumental systematic uncertainty caused by the effective area calibration, which we empirically evaluated using the Crab Nebula spectra. On combining these results, we found no significant line features above the baryonic thermal emission from the intra-cluster medium. The upper limit at 3.5 keV, at a 3σ confidence level, is tightly constrained to 4.2 × 10−5 photons cm−2 s−1 for the $15^{\prime }$ circular sky region, which encloses a dark matter mass of $1.67\times 10^{14}\, M_{\odot }$, assuming a line velocity dispersion of 180 km s−1. This constraint is three times tighter than the previous one, which only used the SXS. On the basis of these findings, we provide the upper limit of the dark matter decay rate and the mixing angle for the sterile neutrino origin.

Performance of different nebulizers in clinical use for Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC).

Technical ex-vivo comparison of commercial nebulizer nozzles used for Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC). The performance of four different commercial nebulizer nozzles (Nebulizer; HurriChemTM; MCR-4 TOPOL®; QuattroJet) was analysed concerning: i) technical design and principle of operation, ii) operational pressure as function of the liquid flow rate, iii) droplet size distribution via laser diffraction spectrometry, iv) spray cone angle, spray cone form as well as horizontal drug deposition by image-metric analyses and v) chemical resistance via exposing to a cytostatic solution and chemical composition by means of spark optical emission spectral analysis. The Nebulizer shows quasi an identical technical design and thus also a similar performance (e.g., mass median droplet size of 29 μm) as the original PIPAC nozzles (MIP/ CapnoPen). All other nozzles show more or less a performance deviation to the original PIPAC nozzles. The HurriChemTM has a similar design and principle of operation as the Nebulizer, but provides a finer aerosol (22 μm). The principle of operation of MCR-4 TOPOL® and QuattroJet differ significantly from that of the original PIPAC nozzle technology. The MCR-4 TOPOL® offers a hollow spray cone with significantly larger droplets (50 μm) than the original PIPAC nozzles. The QuattroJet generates an aerosol (22 μm) similar to that of the HurriChemTM but with improved spatial drug distribution. The availability of new PIPAC nozzles is encouraging but can also have a negative impact if their performance and efficacy is unknown. It is recommended that PIPAC nozzles that deviate from the current standard should be subject to bioequivalence testing and implementation in accordance with the IDEAL-D framework prior to routine clinical use.

A Comprehensive Study on Implant Stability Quotient (ISQ) in View of Resonance Frequency and Spectrum Analysis.

This experimental study investigated how well implant stability quotient (ISQ) represents resonance frequency. Benchtop experiments on standardized samples, mimicking a premolar section of a mandible, were conducted to correlate an ISQ value and a resonance frequency to synthetic bone density and an incremental insertion torque. A frequency spectrum analysis was performed to check the validity of the resonance frequency analysis (RFA). Branemark Mk III implants with dimensions ∅4 Å~ 11.5 mm were placed in Sawbones test models of five different densities (40, 30, 40/20, 20, 15 PCF). An incremental insertion torque was recorded during implant placement. To perform stability measurements, the test models were clamped partially in a vise (unclamped volume 10 Å~ 20 Å~ 34 mm). A MultiPeg was attached onto the implants, and a Penguin RFA measured ISQ. Simultaneously, motion of the MultiPeg was monitored via a laser Doppler vibrometer and processed by a spectrum analyzer to obtain the resonance frequency. Tightness of the clamp was adjusted to vary the resonance frequency. A statistical analysis produced a linear correlation coefficient 𝑅 among the measured ISQ, resonance frequency, and incremental insertion torque. The resonance frequency had high correlation to the incremental insertion torque (𝑅 = 0.978), confirming the validity of using RFA for this study. Measured ISQ data were scattered and had low correlation to the resonance frequency (𝑅 = 0.214) as well as the incremental insertion torque (𝑅 = -0.386). The spectrum analysis revealed simultaneous presence of multiple resonance frequencies. For the designed benchtop tests, resonance frequency does indicate implant stability in view of Sawbones density and incremental insertion torque. ISQ measurements, however, do not correlate well to the resonance frequency, and may not reflect the stability when multiple resonance frequencies are present simultaneously.

Detection of Language Lateralization Using Spectral Analysis of EEG.

Language lateralization relies on expensive equipment and can be difficult to tolerate. We assessed if lateralized brain responses to a language task can be detected with spectral analysis of electroencephalography (EEG). Twenty right-handed, neurotypical adults (28 ± 10 years; five males) performed a verb generation task and two control tasks (word listening and repetition). We measured changes in EEG activity elicited by tasks (the event-related spectral perturbation [ERSP]) in the theta, alpha, beta, and gamma frequency bands in two language (superior temporal and inferior frontal [ST and IF]) and one control (occipital [Occ]) region bilaterally. We tested whether language tasks elicited (1) changes in spectral power from baseline (significant ERSP) at any region or (2) asymmetric ERSPs between matched left and right regions. Left IF beta power (-0.37±0.53, t = -3.12, P = 0.006) and gamma power in all regions decreased during verb generation. Asymmetric ERSPs (right > left) occurred between the (1) IF regions in the beta band (right vs. left difference of 0.23±0.37, t(19) = -2.80, P = 0.0114) and (2) ST regions in the alpha band (right vs. left difference of 0.48±0.63, t(19) = -3.36, P = 0.003). No changes from baseline or hemispheric asymmetries were noted in language regions during control tasks. On the individual level, 16 (80%) participants showed decreased left IF beta power from baseline, and 16 showed ST alpha asymmetry. Eighteen participants (90%) showed one of these two findings. Spectral EEG analysis detects lateralized responses during language tasks in frontal and temporal regions. Spectral EEG analysis could be developed into a readily available language lateralization modality.

Development of reversibly photo-crosslinkable water-stable poly(2-ethyl-2-oxazoline) nanofibers via functionalization with cinnamoyl moieties

Poly(2-ethyl-2-oxazoline) (PEtOx) is a potent member of the versatile poly(2-oxazoline) polymer platform with its high hydrophilicity that could be beneficial in numerous biomedical applications, especially in the form of a nanofibrous membrane. However, its water-solubility limits its application in situations where a stable, nanofibrous morphology is required in aqueous environments. The present work offers a straightforward route towards water-stable PEtOx-based nanofibrous membranes, via post-polymerization functionalization with cinnamoyl moieties (PEtOx-Cin) and photo-crosslinking of the electrospun membranes. It is shown that a UVB treatment does not significantly affect the nanofibrous morphology, while successfully inducing the cinnamoyl dimerization process and hence the formation of a polymeric network, as evidenced by spectral analysis. The hereby crosslinked PEtOx-based nanofibers exhibit a prolonged water-stability (at least 45 days), while, interestingly, intermediate irradiation times yield the best results. Full disintegration of the photo-crosslinked nanofibers in aqueous media could be achieved by subsequent UVC exposure. This is not only due to decrosslinking of the cinnamoyl dimers, but was also found to be due to partial degradation of the polymeric backbone. The investigation of UVB/UVC exposure on pure PEtOx nanofibrous membranes confirmed the photo-degradation of the polymeric backbone by a significant decrease in molar mass as observed by size exclusion chromatography and supported by spectral analysis. The hereby proposed, straightforward route for reversible crosslinking of PEtOx-based nanofibrous membranes and their accessible disintegration will contribute to the promotion of these materials in biomedical applications where a water-stable, nanofibrous morphology combined with high hydrophilicity and easy removal is required.

On the role of aortic valve architecture for physiological hemodynamics and valve replacement, Part II: Spectral analysis and anisotropy

Severe aortic valve stenosis can lead to heart failure and aortic valve replacement (AVR) is the primary treatment. However, increasing prevalence of aortic stenosis cases reveal limitations in current replacement options, necessitating improved prosthetic aortic valves. We investigate flow disturbances downstream of severe aortic stenosis and two bioprosthetic aortic valve (BioAV) designs using advanced energy-based analyses. Three-dimensional high-fidelity fluid–structure interaction simulations have been conducted and a dedicated and novel spectral analysis has been developed to characterise the kinetic energy (KE) carried by eddies in the wavenumber space. In addition, new field quantities, i.e. modal KE anisotropy intensity as well as normalised helicity intensity, are introduced. Spectral analysis shows kinetic energy (KE) decay variations, with the stenotic case aligning with Kolmogorov’s theory, while BioAV cases differing. We explore the impact of flow helicity on KE transfer and decay in BioAVs. Probability distributions of modal KE anisotropy unveil flow asymmetries in the stenotic and one BioAV cases. Moreover, an inverse correlation between temporally averaged modal KE anisotropy and normalised instantaneous helicity intensity is noted, with the coefficient of determination varying among the valve configurations. Leaflet dynamics analysis highlights a stronger correlation between flow and biomechanical KE anisotropy in one BioAV due to higher leaflet displacement magnitude. These findings emphasise the role of valve architecture in aortic turbulence as well as its importance for BioAV performance and energy-based design enhancement.

A spectral mixture analysis based framework for estimating and charactering water use efficiency in heterogeneous drylands

Climate change and irrational land utilization have significantly disrupted the function and structure of the dryland ecosystems, leading to tremendously potential effects on the carbon and water cycles of the global terrestrial ecosystems. Ecosystem-scale water use efficiency (WUE) is a crucial metric that defines the ratio of gross primary productivity (GPP) to evapotranspiration (ET), revealing the coupling relationship between such two ecological processes and playing a significant role in water resource management decision-making. However, quantifying WUE in drylands remains a challenge because of their heterogeneous land surface challenging to characterize model parameters using traditional remote sensing techniques. Here, we developed a process-based framework to estimate GPP and ET, as well as WUE based on physical endmember fractions from spectral mixture analysis (SMA) model. And such framework is used to quantify the spatial and temporal evolution of WUE by optimizing the light use efficiency and assisting in the construction of a GV-Cws model for the separation of transpiration and evaporation processes during computation by utilizing the physically fractional vegetation and soil obtained from SMA in the Hexi Corridor of China, a typical dryland ecosystem. The results demonstrate that our framework can accurately estimate GPP and ET in the Hexi Corridor, as indicated by favorable performance in R2 (0.669, 0.705), RMSE (0.383,0.885) and NSE (0.534, 0.690) respectively. Such results surpass the accuracy of both two Moderate Resolution Imaging Spectroradiometer (MODIS) products and Penman-Monteith-Leuning Evapotranspiration V2 (PML_V2)’s ET product. These advantages highlight that our SMA-based framework can provide highly accurate and distinct characterization of surface carbon and water interaction processes. Meanwhile, the WUE of the Hexi Corridor ecosystem exhibited a positive trend from 2001 to 2017 (0.016 gC·m−2·mm−1·a-1), characterized by simultaneous increases in GPP and ET.

An analytical fast field solver for surface permanent magnet co‐axial magnetic gears

AbstractA mathematical model of co‐axial magnetic gears is given for the prediction of magnetic field distribution and the magnetic forces. The modelling approach is based on the separation of variables method (SVM), Sturm–Liouville problem, and spectral analysis. This method is computationally more efficient and has the ability to account for finite permeability of magnetic saliency. An finite element method (FEM) validation is performed for a case study, and the results are observed to be almost matched. The computational time of the analytical model has been almost in the same order of that of the FEM for a specified rotor position (both in a matter of a second or less); however, when 100 number of rotor positions were accounted in the simulation, the computational time of FEM was increased to 82 s, while the computational complexity of SVM was almost unaffected.

Searching for the Highest Energy of Pulsation and Critical Luminosity of Swift J0243.6+6124 Observed by Insight-HXMT

Owing to the broad energy coverage of Insight-HXMT in the hard X-ray band, we detected the highest energy of pulsation exceeding 200 keV around the 2017–2018 outburst peak of the first Galactic pulsating ultraluminous X-ray source (PULX) Swift J0243.6+6124, which is the highest energy detected from PULXs to date. We also obtained the highest energy of pulsation of every exposure during the outburst in 2017–2018, and found the highest energy is roughly positively correlated with luminosity. Using our newly developed method, we identified the critical luminosity being 4 × 1038 erg s−1 when the main peaks of the low and high energy pulse profiles became aligned, which separates the fan-beam dominated and pencil-beam dominated accretion regimes. Above the critical luminosity, the phase of the main peak shifted gradually from 0.5 to 0.8 until the outburst peak in all energy bands is reached, which is in agreement with the phase shift found previously at low energies. Our result is consistent with what is derived from spectral analysis.

Studies on the synthesis, growth, and characterization of 2-cyanopyridinium salicylate single crystals for nonlinear optical applications

By employing methanol as the solvent in slow solvent evaporation method, a new nonlinear optical organic single crystal of 2-cyanopyridinium salicylate (2-CPSC) was grown. The lattice parameters of the 2-CPSC crystals were found out to be a = 7.7764(9) Å, b = 12.3938(17) Å, c = 12.3685(18) Å, and β = 94.44º using single crystal X-ray diffraction (SCXRD) analysis. The confirmation of crystalline nature was done by powder XRD analysis. The 2-CPSC crystal's chemical composition and functional groups were confirmed by Fourier transform infrared (FTIR) spectral analysis. The optical study was done by ultraviolet-visible-near infrared (UV–Vis-NIR) spectral analysis showing a cutoff wavelength of 338 nm. Studies on the grown 2-CPSC crystal's dielectric and Vicker's microhardness were also conducted. The linear dependence of photocurrent with the applied electric field was revealed for the grown crystals. The 2-CPSC crystal's third-order nonlinearity was investigated by the single-beam Z-scan technique using a continuous He-Ne laser. The open aperture Z-scan reveals the two-photo absorption mechanism and the closed aperture Z-scan study reveals the positive nonlinearity of the 2-CPSC crystals with third order susceptibility value of χ3=2.6763×10−6(esu). The density functional theory (DFT) method of B3LYP level with the 6–31++G(d,p) basis set was used for different quantum chemical calculations like geometry optimization, natural bond orbital (NBO) analysis, mulliken atomic charge, and molecular electrostatic potential (MEP). The higher nonlinearity of the 2-CPSC can be a potential alternative for commercially available potassium dihydrogen phosphate (KDP) and candidate for its application in nonlinear optical devices like optical limiting and optical switching.

Numerical Simulation of Ship-added Resistance Based on a Numerical Wave Tank

The wave resistance increase of a ship during its actual voyage can affect its speed and safety. To design ships with excellent sailing performance, it is necessary to accurately predict the wave resistance increase of a ship in waves, as well as the motion response and wave resistance prediction of ships in waves, which involves complex hydrodynamic problems. This paper first establishes a physical model of the KCS vessel, then utilizes the numerical wave tank platform independently developed by our university. Based on viscous flow theory, it calculates the resistance of the KCS under calm water conditions. Using three-dimensional potential flow methods and spectral analysis, it computes the wave-induced resistance values for the KCS under six-degree sea states, analyzes the wave-induced resistance performance of the KCS, and ultimately, based on the calculation results of calm water resistance and wave-induced resistance combined with propeller efficiency parameters, calculates the effective power of the engine.

New insight into the hard X-ray emission influenced by the type I bursts observed by Insight-HXMT during the outburst of 4U 1636–536

Context. Thermonuclear bursts, also known as type I X-ray bursts, result from unstable nuclear burning of H/He accreted to the surface of neutron stars, lasting from tens to hundreds of seconds. Thermonuclear bursts have an important impact on accretion environments around the neutron stars, such as their disks and coronas, and are therefore a subject of extensive research. Thermonuclear bursts can be used as probes to gain a deeper understanding of the properties of their disks and coronas. Aims. By analyzing the data from Insight-HXMT and NICER, we can determine the evolution of the significance of the hard shortage in 4U 1636–536 with its spectral state, as well as the evolution of the fraction of deficit with energy. Additionally, we investigate the possible geometry and evolution of the corona in 4U 1636–536 by combining our findings with the results of spectral analysis. Methods. We extracted the light curves from the Insight-HXMT low-energy, medium-energy, and high-energy data and subtracted their pre-burst emission, which allowed us to estimate the significance of the hard shortages during the bursts. By fitting the spectra, the correlation between the persistent spectral parameters and the significance of the hard shortages could be established. The bursts were then grouped according to the spectral state in which they occurred, and the significance of the hard shortages was estimated. These in turn helped to investigate the evolution of the fraction of deficit with energy. Results. We find that during the soft state the significance of possible hard X-ray shortage in bursts is almost zero. However, in the hard state, some bursts exhibit significant shortages (> 3σ), while others do not. We attempt to establish a correlation between the significance of the hard X-ray shortage and the spectral parameters, but the data quality and the limited number of bursts prevent us from finding a strong correlation. For bursts with insignificant shortages in the soft state, the fraction of the deficit remains small. However, in the hard state the fraction of deficit for all bursts increases with energy, regardless of the significance of the shortage of individual bursts. For bursts during the hard state, we investigated the evolution of the fraction of deficit during the bursts by stacking the peaks and decays of the bursts, and find that as the flux of the bursts decreases, the energy corresponding to the maximum of the fraction of deficit becomes progressively higher. Conclusions. We explore the possible geometry and evolution of the corona suggested by the evolution of the fraction of deficit, which is obtained from the spectral and temporal analysis.

Micro-Spectrometer-Based Interferometric Spectroscopy and Environmental Sensing with Zinc Oxide Thin Film

This study introduces a novel approach for analyzing thin film interference spectra by employing a micro-spectrometer equipped with a spectral chip. Focusing on zinc oxide (ZnO) thin films prepared via the sol–gel method, this research aims to explore the films’ physical properties through spectral analysis. After obtaining the interference spectrum of the ZnO thin films, the peak positions within the spectrum were cataloged. Mathematical simulation was used to adjust the refractive index and thickness of the films to match the simulated interference peak positions with the observed peak positions. The thickness of the prepared ZnO film was estimated to be 4.9 μm and its refractive index at 80 °C was estimated to be 1.96. In addition, the measurement system was used to detect environmental changes, including temperature changes and gas exposure. It was observed that the optical characteristics of ZnO films exhibit marked variations with temperature shifts, enabling the establishment of a temperature calibration curve based on spectral feature displacement. In addition, experiments using a variety of gases showed that NO2 and gaseous isopropanol significantly affect the interference spectrum of ZnO, with the peak of the interference spectrum shifted by 2.3 nm and 5.2 nm, respectively, after injection of the two gases. This indicates that interferometric spectroscopy can serve as an effective tool for ZnO monitoring, capable of selectively detecting specific gases.

Advanced Tuning of electric and dielectric properties in Ba0·5Ni0.5-xCdxFe2O4 spinel ferrites for high-frequency devices with barium dopants

Spinel ferrites are vital in developing next-generation technologies with potential applications covering the medical, electronic, and material industries. Nickel-cadmium spinel ferrites are soft magnetic materials having lots of applications ranging from electronics and magnetic to sensors industries. Herein, we developed cadmium-substituted spinel ferrites (Ba0·5Ni0.5-xCdxFe2O4) and their nanocomposite with polymer polyvinyl alcohol (PVA). The results evidently indicate that the successfully developed Ba0·5Ni0.5-xCdxFe2O4, which also confirmed the loading of PVA onto the Ba0·5Ni0.5-xCdxFe2O4 materials. XRD results confirmed orthorhombic single-phase structure. The optimal particle size was 27.22 nm, and the minimum was 21.25 nm, respectively, as shown by Ba0·5Ni0·1Cd0·4Fe2O4 (x = 0.4) and PVA composite of Ba0·5Ni0·2Cd0·3Fe2O4 (x = 0.3). It was also observed that the composites showed lower particle size than nano-ferrites. Spectral analysis (Fourier Transform Infrared Spectroscopy) confirmed the formation of spinel ferrites by detecting the M − O bonds in the 400-800 cm−1 region. υ1 and υ2 were appeared in the range 560–609 cm−1 and 439-466 cm−1, corresponding to M-O. The average grain size of spinel ferrites was 0.55, 0.50, 1.03, and 1.31 μm for Ba0·5Ni0.5-xCdxFe2O4 (x = 0.1, 0.2, 0.3, and 0.4) spinel ferrites. Dielectric parameters revealed that these materials are suitable for high-frequency devices due to their low dielectric loss, high quality factor, short relaxation time, and diverse responses.

Advanced diagnostic techniques for turbo compressors: A spectral analysis approach for preventive maintenance

This paper introduces an innovative spectral analysis control approach aimed at monitoring and diagnosing machine malfunctions to prevent potential failures. The research was conducted on a critical machine in a major industrial enterprise. The proposed method involves the use of a new indicator, called Overall Level (OL), that evaluates the machine’s condition before any operation. This study showcases practical methodologies for transitioning from time-based maintenance to predictive strategies, furnishing actionable insights into machine condition. This yields tangible advantages for the industry in terms of optimizing maintenance practices and enhancing asset productivity. Additionally, various methods, including vibration analysis, performance monitoring, and data analysis, are employed to identify the causes of issues and recommend solutions to enhance the reliability of the turbo compressor. The results provide a clear representation of the machine’s vibration state for diagnostic purposes. This noteworthy intervention underscores the potential of incorporating the measured and calculated values of the OL indicator across three specifically chosen frequency bands. To achieve this objective, the average value is employed as an indicator, contributing to the enhancement of reliability and longevity of critical industrial machinery. In this context, the novelty of the findings resides in the advanced diagnostic capabilities of the turbocompressor, thereby augmenting the efficacy of condition-based preventive maintenance for the BP 103 J turbine. The ultimate goal is to extend the equipment’s lifespan, improve the efficiency of the rotating machinery fleet, reduce maintenance costs, and enhance parameters such as availability and reliability through the support of an electronic maintenance system.

Variation of vortical structures across shock-wave/turbulent boundary-layer interaction region in a compression ramp flow

This paper describes direct numerical simulations of a shock-wave/turbulent boundary-layer interaction (STBLI) process in a compression-ramp flow with a ramp angle of 24° and a free-stream Mach number of Ma∞=2.9. Spectral analysis, two-point cross correlation, convection velocity statistics, and individual vortex identification are used to elucidate the streamwise variation of multiscale turbulent structures in the STBLI process. Typical Lagrangian coherent structures in the turbulent boundary layer before the STBLI region are characterized as hairpin-like vortical structures, with heads that rise together with the separated mean flow in the STBLI region. In the downstream region, the reattached turbulent boundary layer has a two-layer structure. The outer layer is characterized as an intensification of large-scale velocity structures, which is attributed to the shock-wave-induced compression effect on vortical structures. A viscous-dominated layer develops independently in the vicinity of the wall, leading to a gradual restoration of the wall-shear effect that accumulates the inner-layer dynamics of small-to-moderate-scale turbulent motions.

Unveiling the Therapeutic Potential of Organotellurium(IV) Schiff Base Complexes through Structural Elucidation, Antimalarial, Antioxidant and Antimicrobial Studies

Infectious diseases have long been a formidable adversary to human health and well-being, presenting a persistent global challenge with far-reaching implication for individuals, communities and societies at large. Thus, with the aim of a combating agent against malarial and oxidant causing ailments, the newly synthesized Organotellurium(IV) complexes with a hydroxynaphthaldehyde Schiff base ligand are proposed in the present research. The structures of the complexes were established through various physical and spectral analysis. The weak electrolytic (8.77 to 35.08 ohm−1 cm2 mol−1) and crystalline nature of the compounds were demonstrated by molar conductivity and TGA, respectively. The ligand and complexes (7a-7f) shows molecular ion peaks at m/z 458.3563, 726.1039, 713.6978, 727.6179, 799.4780, 771.3178 and 799.3978 amu which were well consistent with their formula, revealing formation of compounds. The shifting of ligand's azomethine peak (7.74 ppm) and disappearance of naphthyl hydroxyl proton (12.28 ppm) in 1H NMR spectra confirmed the chelation of ligand with metal ion in proposed manner. In the FT-IR spectra, the complexation of ligand with metal ion was confirmed by disappearance of hydroxyl group (3355 cm−1) band and shifting of C=N (1245 cm−1) and C-O (1632 cm−1) band whereas appearance of Te-O (of 285-293 cm−1) and Te-N (458-467 cm−1) bands, revealed the bonding of metal with metal and octahedral nature of the complexes. Optimized structures, HOMO-LUMO energies and associated chemical reactivity descriptors of the compounds were computed by DFT calculations. The in vitro studies demonstrate that the complexes 7c (1.06 ± 0.11 μM) and 7f (1.22 ± 0.05 μM) exhibited moderate inhibition of the Plasmodium falciparum 3D7 strain, complexes 7a (100.96 ± 0.32 μg/mL) and 7d (96.32 ± 0.40 μg/mL) demonstrated the highest free radical quenching ability. Complex 7c displayed the highest antibacterial actions, whereas 7f exhibited the highest antifungal actions against the tested pathogens. Molecular docking and ADMET studies demonstrated enhanced binding affinity of the complexes compared to the Schiff base and their drug-like qualities.

On the Spatio-temporal Dynamics of Cavitating Turbulent Shear Flow Over a Microscale Backward-Facing Step: A Numerical Study

The influence of cavitation on the mean characteristics and unsteady behavior of turbulent separated flows was comprehensively investigated in this study over a microscale backward-facing configuration at the Reynolds number (ReD) of 7440. The computational approach took both compressibility and finite mass transfer (Thermodynamic non-equilibrium) into account, to accurately capture the effects of shock waves, as well as to capture baroclinic phenomena on vortex dynamics within the turbulent separated flow. The compressibility effects were handled by using appropriate equation of states for each phase and for the mixture. Phase-change was considered through a transport equation for the vapor volume fraction, allowing for finite mass transfer contributions. Additionally, a wall adaptive large eddy simulation (LES) approach was utilized for simulating turbulent structures and their effects. The findings reveal that vapor development diminishes the mean growth rate of the shear layer and delays its reattachment to a longer distance from the step. Moreover, analysis of Reynolds normal and shear stresses, as well as the root mean square (RMS) of pressure fluctuations, demonstrates that the formation and collapse of vapor packets significantly influence turbulence decay and production in the second half of the shear layer and reattachment. It was also observed that both mean pressure and pressure fluctuations increased in vicinity of the reattachment region when cavitation was present, which was attributed to the condensation and collapse events. Spectral analysis further indicates the emergence of two dominant low frequency modes, linked to the displacement of the reattachment point. In the presence of cavitation, the frequencies associated with dominant Power Spectral Densities (PSDs) were smaller than those in the absence of cavitation. Additionally, each of these low frequencies corresponded to a specific vapor transport mechanism within the Turbulent Separation Bubble (TSB). Furthermore, it is shown that cavitation leads to a significantly higher spectral energy of high frequency fluctuations within the reattachment region in comparison to the condition where cavitation is absent. This can be attributed to the frequent collapse of bubbles in this region. At the end, we employed Spectral Proper Orthogonal Decomposition (SPOD) for modal analysis. This method offers valuable insights into the coherent structures and associated frequencies that arise in both the presence and absence of cavitation, which provides a deeper understanding of the effect of cavitation on the coherent structures and their dynamics.