Frequency Matching Research Articles

Abstract 6617: Oral microbiome and subsequent risk for head and neck squamous cell cancer development

Abstract Background: The oral microbiota may be involved in head and neck squamous cell cancer (HNSCC) etiology, yet current evidence is largely limited to bacterial 16S amplicon sequencing or small retrospective case-control studies. We tested whether any oral bacteria and/or fungi influence the subsequent risk of HNSCC development. Methods: We conducted a prospective case-control study nested within three epidemiological cohorts: the ACS-Cancer Prevention Study-II Nutrition Cohort (ACS-CPS-II), the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO), and the Southern Community Cohort Study (SCCS). Among 159,840 cohort participants, 236 individuals developed HNSCC during an average of 5.1 years of follow-up, and 485 controls who remained HNSCC-free were selected by 2:1 frequency matching, by cohort, age, sex, race/ethnicity, and time since mouthwash collection. All participants provided mouthwash samples and were cancer-free at baseline. We characterized the oral bacterial microbiome, using whole-genome shotgun sequencing, and the oral fungal microbiome, using ITS sequencing. We assessed relative abundance of microbiome-wide bacterial and fungal taxa for association with HNSCC by ANCOM-BC analysis. We also evaluated selected oral pathogen complexes for association with HNSCC by logistic regression. A microbial risk score (MRS) for HNSCC risk was calculated from all risk-associated microbes. Results: Overall microbiome diversity at baseline was not related to the subsequent risk of HNSCC; however, we found that 13 oral bacterial species were differentially associated with development of this disease (P<0.05), including newly identified Prevotella salivae, Streptococcus sanguinis, Leptotrichia sp, and several species belonging to Beta- and Gamma-proteobacteria. Furthermore, a priori periodontal pathogen complexes were associated with a higher risk of HNSCC (“red/orange” complex, OR=1.06, 95% CI=1.00-1.12). We did not identify any fungal taxa associated with HNSCC risk. Together, an MRS constructed for risk-associated bacteria and bacterial periodontal complexes conferred a 50% increase in HNSCC risk, per standard deviation increase in the MRS (multivariate OR=1.50, 95% CI=1.21-1.85). Conclusions: Our research yields compelling evidence that oral bacteria are a risk factor for the development of HNSCC. The identified bacteria and bacterial complexes hold promise for identifying high-risk individuals and may further lead to personalized prevention approaches for HNSCC. Citation Format: Soyoung Kwak, Mykhaylo Usyk, Feng Wu, Neal D. Freedman, Wen-Yi Huang, Marji L. Mccullough, Caroline Y. Um, Martha J. Shrubsole, Qiuyin Cai, Chan Wang, Huilin Li, Jiyoung Ahn, Richard B. Hayes. Oral microbiome and subsequent risk for head and neck squamous cell cancer development [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6617.

Deterministic Shaping of Quantum Light Statistics

We propose a theoretical method for the deterministic shaping of quantum light via photon number state selective interactions. Nonclassical states of light are an essential resource for high-precision optical techniques that rely on photon correlations and noise reshaping. Notable techniques include quantum enhanced interferometry, ghost imaging, and generating fault-tolerant codes for continuous variable optical quantum computing. We show that a class of nonlinear-optical resonators can transform many-photon wavefunctions to produce structured states of light with nonclassical noise statistics. The devices, based on parametric down conversion, utilize the Kerr effect to tune photon-number-dependent frequency matching, inducing photon-number-selective interactions. With a high-amplitude coherent pump, the number-selective interaction shapes the noise of a two-mode squeezed cavity state with minimal dephasing, illustrated with simulations. We specify the requisite material properties to build the device and highlight the remaining material degrees of freedom which offer flexible material design.

An experimental investigation on the influence of Strouhal number and amplitude on the flow and heat transfer behavior of synthetic jet impingement

ABSTRACT Here, tests are performed to analyze the effect of Strouhal number (St) and amplitude on thermo-fluid characteristics of synthetic jet (SJ) impingement for varied range of Reynolds numbers (Re = 3000–6000) and three different SJ actuation amplitudes (Vrms = 4, 6, 8 V). The hot wire anemometer and the infrared thermal imaging camera are used to measure the flow velocity and surface temperature, respectively. At a constant amplitude of the SJ actuation, discrete pairs of Strouhal numbers, i.e. low St ( S t L ) and high St ( S t H ), are found to exhibit the same Re. The heat transfer characteristics are expressed in three different regions such as the region of recirculation, the region of high Strouhal number dominance, and the region of low Strouhal number dominance. At lower orifice-to-surface spacings (z/d < 6), the thermal efficacy of SJ with S t H is found to be lower compared to the SJ with S t L . At z/d = 2, SJ with S t H exhibits the decrease in the average Nusselt number upto 53.4% corresponding to S t L at Re = 4000 and 4 Vrms. However, at intermediate spacings (z/d ≥ 6 ), the SJ with S t H tends to outperform the S t L , which may be due to vortex pairing at high St synthetic jets. At larger z/d, the dominance of S t L is reestablished due to matching of the SJ actuation frequency with the natural frequency of a steady jet. Correlations have been proposed for the average Nusselt number at both S t L and S t H as a function of Re, St, and z/d. The results of the study provide information on the selection of the operating frequency of SJ to achieve higher heat transfer at varied orifice-to-surface spacings.

Abstract B017: Disease free survival as a predictor of overall survival in patients with high-risk endometrial cancer receiving adjuvant chemotherapy

Abstract Introduction: Disease-free survival (DFS) is often evaluated as a primary endpoint in early settings for several cancers, including endometrial cancer (EC). However, the role of DFS as a potential predictor of overall survival (OS) in EC is unknown. Elucidating the association between DFS and OS in EC is critical for contextualizing findings from trials where DFS is a primary endpoint, such as KEYNOTE-B21, which assesses the effect of treatment with pembrolizumab + adjuvant chemotherapy (CTX) vs. adjuvant CTX, with or without radiotherapy in patients with EC at high risk of recurrence. This real-world study assessed the association between DFS and OS and the impact of recurrence on OS in elderly patients with EC at high risk of recurrence receiving adjuvant CTX. Methods: SEER-Medicare data (2007–2019) were used to identify patients with EC at high risk of recurrence who received adjuvant CTX with or without radiotherapy. Patients were defined as high risk of recurrence if they had either Stage I or II EC with non-endometroid histology or Stage III or IVA EC with any histology. An EC recurrence was defined as having a diagnosis with a distinct secondary cancer &amp;gt;90 days after end of adjuvant CTX or receipt of additional cancer treatment &amp;gt;90 days after end of adjuvant CTX. Kaplan-Meier (KM) analyses were used to estimate OS (time from initiation of adjuvant therapy [index date] to death) and DFS (time from index date to earliest of recurrence or death). The correlation between DFS and OS was assessed using Kendall’s τ rank correlation. Landmark analyses were used to compare OS between patients with vs. without a recurrence at 1-, 3-, and 5-years post the index date; hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using adjusted Cox models. KM analyses were used to estimate OS from a recurrence (index date) for recurrent patients and from an imputed index date (using frequency matching) for non-recurrent patients. Results: Of 794 eligible patients, 253 (31.9%) experienced a recurrence over a median follow up of 3.6 years. Median age at diagnosis was 71.9 years, 69.8% had stage I/II disease, and 86.6% had non-endometrioid carcinoma. Median OS was not reached (5-year OS: 72.5%) and median DFS was 7.9 years (5-year DFS: 58.7%). A significant positive correlation between DFS and OS was observed (Kendall’s τ =0.83; 95% CI: 0.79–0.86; p&amp;lt;0.001). Patients with a recurrence had significantly higher risk of death than those without, at landmark points 1- (HR: 4.4; 95% CI: 2.8–7.0; p&amp;lt;.001), 3- (HR: 5.2; 95% CI: 3.1–8.7; p&amp;lt;.001), and 5-years (HR: 5.1; 95% CI: 2.2–11.7; p&amp;lt;.001). Patients with a recurrence had significantly shorter median OS than those without (median OS: 1.4 years vs. not reached; p&amp;lt;.001). Conclusions: In elderly patients with EC at high risk of recurrence who received adjuvant CTX, DFS was strongly correlated with OS and having a recurrence was associated with significantly higher risk of death. Our findings suggest that DFS is a strong predictor of OS in this population and may be a useful surrogate endpoint. Citation Format: Kalé Kponee-Shovein, Vimalanand S. Prabhu, Yan Song, Lei Chen, Mu Cheng, Yeran Li, Yezhou Sun, Annalise Hilts, Qi Hua, Jasmine Lichfield, Linda Duska. Disease free survival as a predictor of overall survival in patients with high-risk endometrial cancer receiving adjuvant chemotherapy [abstract]. In: Proceedings of the AACR Special Conference on Endometrial Cancer: Transforming Care through Science; 2023 Nov 16-18; Boston, Massachusetts. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(5_Suppl):Abstract nr B017.

Проектирование двухдиапазонных антенн на основе возбудителя дипольного вида с концевым типом возбуждения

The project is aimed at the designing, based on a systematic approach to the design of antenna elements and systems, an algorithm for design of dual-band dipole antennas with non-traditional excitation. The ends-fed excitation technique, proposed in the work, makes it possible to space the central part of the substrate for placing additional radioelectronic components, and at the same time to reduce the electromagnetic interaction of the supply strips of the balun circuit. The proposed excitation technique allows designing new types of antenna, such as cardioid antenna, turnstile antenna, antenna array with principally different electrodynamic regimes. The parametric optimization algorithm for the thin-wire model, as well as the printed equivalent, is based on formal relationships for the input impedance and the generalized directivity function of the driver proposed. The corresponding closed-form expressions specify initial approximations of independent geometry parameters calculated for given central matching frequencies. The stated sequence of procedures allows, within the framework of a systematic approach, to determine the initial approximations of the geometric parameters of the driver. At subsequent design stages, the problem of pairing the driver and the matching-balun circuit is solved. Thus, the entire task is decomposed into independent computational blocks, simplifying and reducing computational costs.

Exploring comb filtering effects in the recording studio: A lesson on room acoustics

A common practice during a live music-recording session is to position microphones, so-called, “room mics” to capture the ambient characteristics of the recording space. An in-class, hands-on experiment was conducted at Belmont University’s Historic Columbia Studio A in order to measure and observe the effect of comb filtering on the signal captured by an on-axis room microphone placed at various heights from the floor. A total of seven positions were recorded, spanning from just above the floor to twelve feet in the air. Sine sweep measurements and musical samples from a live virtual jazz-quartet were taken at each position. Students were then asked to listen back and discuss their preferences for each microphone height, comparing their observations to the matching frequency response analysis. A majority of students enjoyed the recording with the microphone positioned at the floor corresponding with the least amount of comb filtering. Although listener preference data was not collected, this experiment demonstrated the use of interdisciplinary examples as an educational tool in the field of acoustics.

Performance Analysis in Children of Traditional and Deep Learning CT Lung Nodule Computer-Aided Detection Systems Trained on Adults.

BACKGROUND. Although primary lung cancer is rare in children, chest CT is commonly performed to assess for lung metastases in children with cancer. Lung nodule computer-aided detection (CAD) systems have been designed and studied primarily using adult training data, and the efficacy of such systems when applied to pediatric patients is poorly understood. OBJECTIVE. The purpose of this study was to evaluate in children the diagnostic performance of traditional and deep learning CAD systems trained with adult data for the detection of lung nodules on chest CT scans and to compare the ability of such systems to generalize to children versus to other adults. METHODS. This retrospective study included pediatric and adult chest CT test sets. The pediatric test set comprised 59 CT scans in 59 patients (30 boys, 29 girls; mean age, 13.1 years; age range, 4-17 years), which were obtained from November 30, 2018, to August 31, 2020; lung nodules were annotated by fellowship-trained pediatric radiologists as the reference standard. The adult test set was the publicly available adult Lung Nodule Analysis (LUNA) 2016 subset 0, which contained 89 deidentified scans with previously annotated nodules. The test sets were processed through the traditional FlyerScan (github.com/rhardie1/FlyerScanCT) and deep learning Medical Open Network for Artificial Intelligence (MONAI; github.com/Project-MONAI/model-zoo/releases) lung nodule CAD systems, which had been trained on separate sets of CT scans in adults. Sensitivity and false-positive (FP) frequency were calculated for nodules measuring 3-30 mm; nonoverlapping 95% CIs indicated significant differences. RESULTS. Operating at two FPs per scan, on pediatric testing data FlyerScan and MONAI showed significantly lower detection sensitivities of 68.4% (197/288; 95% CI, 65.1-73.0%) and 53.1% (153/288; 95% CI, 46.7-58.4%), respectively, than on adult LUNA 2016 subset 0 testing data (83.9% [94/112; 95% CI, 79.1-88.0%] and 95.5% [107/112; 95% CI, 90.0-98.4%], respectively). Mean nodule size was smaller (p < .001) in the pediatric testing data (5.4 ± 3.1 [SD] mm) than in the adult LUNA 2016 subset 0 testing data (11.0 ± 6.2 mm). CONCLUSION. Adult-trained traditional and deep learning-based lung nodule CAD systems had significantly lower sensitivity for detection on pediatric data than on adult data at a matching FP frequency. The performance difference may relate to the smaller size of pediatric lung nodules. CLINICAL IMPACT. The results indicate a need for pediatric-specific lung nodule CAD systems trained on data specific to pediatric patients.

A sequency match filtering algorithm based on the generalized Walsh transform for processing rectangular wave signals.

The conventional Walsh function just takes values of +1 and -1 and can only track limited signal states. However, based on the characteristics of Walsh functions that can capture the frequency of square wave signals, this article proposes a generalized Walsh transform algorithm to process multi-valued rectangular wave signals. As an extension of the traditional Walsh functions, generalized Walsh functions have advantages in signal frequency matching and sequency spectrum amplitude extraction, which makes them well suited to express the valuable signal. First, we infer the invariance displacement theory in the time and sequency domains, limiting the value of a circular time shift to ensure the concentrated distribution of the signal sequency energy. This limitation lays a good foundation for constructing generalized Walsh functions. Then, two types of generalized Walsh functions are built by combining the characteristics of different periodic rectangular waves. We deduce two properties of orthogonality and completeness to prove the ability of the constructed functions to match the frequency and the extracted energy. Finally, we compare multiple filtering methods to verify the reliability of the proposed method.

P1106 Is indoor radon associated with new diagnosis of inflammatory bowel disease patients?

Abstract Background Inflammatory Bowel Diseases (IBD) are a group of pathologies of unknown etiology associated with some environmental factors, only partially identified. The role of indoor radon, a radioactive gas, has not been formally studied and it might play a role on the onset of the disease. The aim of this study is to analyze the role of individual residential radon exposure on the incidence of IBD in a radon-prone area also characterized as a high incidence IBD region. Methods A case-control study was developed in the health area of Santiago de Compostela (Galicia, Spain) between June 2020 and September 2023, including incident cases with IBD. Controls were selected trough a frequency matching based on sex and age and without IBD. All participants had to be living at least 5 years in the same dwelling, those with a change of address in the last 5 years prior to diagnosis were excluded. Endoscopic index, imaging techniques and analytic parameters were collected. Radon levels measured over three months in the participants’ home were compared between cases and controls, and between the different types of IBD. Each individual was provided with a residential radon meter (a RSKS trace detector), given and read by the Galician Radon Laboratory, a certified radon laboratory. Procedure is summarized in Figure 1. Radon concentrations were categorized into three groups, 0-99 Bq/m3, 100-299 Bq/m3 and &amp;gt;299 Bq/m3. Results are expressed as Odds Ratios with their 95%CI obtained through logistic regression. Results 178 incident cases and 178 controls (102 ulcerative colitis, 70 Crohn’s disease and 6 unclassified colitis) were included, with a median age of 51 years old (IQR 40 – 59.5). 51.7% were females. Median radon levels of IBD patients´ homes were 144.5 (IQR 83 – 260) and median radon levels of controls´ homes were 189.5 (IQR 112 – 292.5) (figure 1). Adjusting by age and sex, high radon levels showed a negative association for the development of IBD (taking levels of 0-99 Bq/m3 as reference, OR 100-299 Bq/m3 is 0.5 (95%CI 0.3-0.8), and OR &amp;gt;299 Bq/m3 is 0.5 (95%CI 0.3-0.9). Results are shown in table 1. Analyzing women and men separately, there are no statistically significant differences (p&amp;gt;0.05 in each group). Taking into account the different types of IBD, radon levels show the same negative association but without statistical association. Conclusion High radon levels might be a protective factor for developing IBD overall and its most common types, Crohn’s disease and ulcerative colitis. Further studies in other areas with lower radon concentrations will be necessary to corroborate whether it influences the incidence of IBD.

Evaluation of the Effects of an Undenatured Collagen Type-2-Based Nutraceutical (ARTHROSHINE® HA²) on Recovery Time after TPLO in Dogs: A Prospective, Randomized Study with Objective Gait Analysis as the Primary Outcome Measure.

This randomized, prospective clinical trial investigates the impact of a novel undenatured collagen type 2 (T2NDC)-based nutraceutical, ARTHROSHINE® HA² (AS), on postoperative rehabilitation following Tibial Plateau Leveling Osteotomy (TPLO) in 50 dogs with unilateral cranial cruciate ligament rupture (CCLR). The patients were randomly allocated to either group A, receiving AS once daily for 24 weeks post-TPLO surgery, or group B, without any supplementation. Frequency matching was applied to enhance group comparability. Assessment of outcomes included computerized gait analysis and a validated owner questionnaire. AS supplementation was well received, without any reported side effect. Consistently, patients in group A exhibited significantly higher peak vertical force values during all follow-up assessments. By the 12-week mark, gait analysis indicated a return to a physiological gait pattern in group A, while group B achieved this normalization only by the 24-week point. The administration of AS post-TPLO surgery demonstrates promise in enhancing limb function, leading to faster restoration of a physiological gait pattern. The inclusion of AS, a T2NDC-based nutraceutical, in the post-TPLO rehabilitation protocol may contribute to improved limb function and an expedited recovery, potentially facilitating a quicker return to normalcy. It is noteworthy that subjective owner perceptions did not differ between the two groups.

Utilizing Gate-Controlled Supercurrent for All-Metallic Tunable Superconducting Microwave Resonators.

Hybridizing a microwave mode with a quantum state requires precise frequency matching of a superconducting microwave resonator and the corresponding quantum object. However, fabrication always brings imperfections in geometry and material properties, causing deviations from the desired operating frequencies. An effective and universal strategy for their resonant coupling is to tune the frequency of a resonator, as quantum states like phonons are hardly tunable. Here, we demonstrate gate-tunable, titanium-nitride (TiN)-based superconducting resonators by implementing a nanowire inductor whose kinetic inductance is tuned via the gate-controlled supercurrent (GCS) effect. We investigate their responses for different gate biases and observe 4% (∼150 MHz) frequency tuning with decreasing internal quality factors. We also perform temperature-controlled experiments to support phonon-related mechanisms in the GCS effect and the resonance tuning. The GCS effect-based method proposed in this study provides an effective route for locally tunable resonators that can be employed in various hybrid quantum devices.

Reduced order modeling of delta operator systems by optimal frequency fitting approach

The delta operator modeling provides a unified framework for both continuous-time and discrete-time modeling in system theory. At high sampling rate, the shift operator fails to provide meaningful information whereas, the delta operator parameterized system provides the same results as of continuous time systems. In this paper reduced order modeling of delta operator parameterized systems is considered. A complex domain (δ) optimal frequency matching (OFM) technique is proposed and frequency points are optimized using Particle Swarm Optimization (PSO) algorithm. This OFM is then utilized to find the reduced order model of the higher order system. PSO algorithm is a robust, global optimization technique, used to find these OFMs and thereby used to find the coefficients of the reduced order model by minimizing a cost function developed based on the responses of the higher order model and that of the reduced order model when both are excited by pseudo random binary sequences (PRBS). The performance characteristics are evaluated in software simulation using MATLAB considering example of higher order system in delta domain and time & frequency responses of the corresponding reduced model.

Microwave absorption properties of oriented Sm2Fe14BHx/polyurethane with planar anisotropy

Realization of microwave-absorbing materials with “small thickness, light weight, broad bandwidth, and low reflectivity” is an invariable topic. In this paper, Sm2Fe14BHx/polyurethane (SFBH/PU) composites with planar anisotropy were prepared by reduction–diffusion (R/D) and water bath hydrogenation (WBH) process. A minimum reflection loss (RL) value reaches −59.7 dB at the perfect matching frequency of 13.79 GHz with a thickness of only 1.035 mm. Compared with unhydrogenated SFB, the bandwidth and reflectivity are significantly improved. It is mainly attributed to the fact that introduction of hydrogen atoms effectively modulates the electromagnetic parameters and increases the Snoek limit ((μi−1)fr), which leads to the improvement of the high-frequency microwave absorption performance. In addition, the bandwidth equation is derived and simplified from the perspective of the reflected wave at the interface, which is in good agreement with the measured results.

Investigation of Sn and Zr co-doped Ba0.5 Sr0.5 TiO3 for dielectric, impedance and conductivity behaviour in temperature and frequency region of measurement

In this report, we are presenting the effect of B-site co-doping with Sn and Zr (2% each) on frequency and temperature-dependent dielectric and electrical properties of Ba0.5Sr0.5TiO3 (BST). The desired compound is synthesised following solid-state reaction route and the structural and micro-structural study of the resulting compound is done using X-ray diffractometer (XRD) and scanning electron microscope (SEM) technique. XRD study revealed that the parent structure of BST is mostly retained after co-doping. SEM micrograph analysis presented dense packing of grains of different sizes distributed all over the volume of compound formed. The compound was found to have a moderate value of dielectric constant and low tangent loss along with a near stable response of these dielectric properties over the studied frequency range, suggesting its possible application in tuneable matching networks and frequency agile antennas. Electrical properties study suggested a non-Debye type electrical response with a thermally activated conduction mechanism occurring in the material. The dependence of conductivity with temperature showed negative temperature coefficient of temperature behaviour of the compound and the ac conductivity spectrum followed Johnscher’s power law. The variation of exponent with temperature suggested correlated barrier hopping conduction mechanism in the material.

Machine Learning-Enhanced ORB Matching Using EfficientPS for Error Reduction

Abstract The study comes up with a new way to improve the accuracy of image matching in binocular vision systems, especially those that are mounted on vehicles. It combines machine learning with the ORB (Oriented FAST and Rotated BRIEF) image-matching algorithms. Standard ORB matching frequently encounters mismatches in complex and repetitive environments. To minimize false positives in matches, our strategy utilizes the EfficientPS (Efficient Panoptic Segmentations) algorithm, a panoramic segmentation technique that uses machine learning in conjunction with ORB. The procedure begins with the EfficientPS approach, which delivers fine-grained and efficient segmentation of images, assigning semantic category labels and unique identifiers to each pixel. The ORB feature point matching process is refined using semantic data to filter out mismatches between foreground objects and the background effectively. This machine-learning-augmented method significantly decreases the frequency of erroneous matches in intricate settings. Empirical findings from the KITTI dataset demonstrate that in non-targeted environments, the accuracy of our proposed method (0.978) is marginally less than that of LoFTR (0.983). Still, it surpasses other methods when utilizing 50 ORB parameters. In more intricate situations, such as multi-target scenarios with an increased number of ORB parameters (200), our method maintains a high level of accuracy (0.883), outperforming the conventional ORB (0.732) and rivaling the performance of DL-BDLMR (0.790) and ORB-MFD-FPMC (0.835). Our method’s processing time is competitive and slightly higher than the standard ORB, but it improves accuracy. In scenarios without targets and with single targets, our method’s processing time (0.195 seconds and 0.211 seconds, respectively) is greater than that of ORB and ORB-MFD-FPMC. Yet, it is significantly lower than that of LoFTR. In multi-target scenarios, our method’s processing time (0.226 seconds) is considerably better than LoFTR’s (0.445 seconds), effectively balancing processing speed and accuracy. We highlight the efficacy of incorporating machine learning to enhance the robustness of image-matching algorithms in dynamic and complex environments.

Bearing Fault Feature Extraction via Adaptive Frequency Matching and Coupling Analysis

Bearing Fault Feature Extraction via Adaptive Frequency Matching and Coupling Analysis

Using Multiple Stator Windings and Multi-Level Converters for Frequency Matching in Microturbine Generators

Using Multiple Stator Windings and Multi-Level Converters for Frequency Matching in Microturbine Generators

The strength of the OH-bend/OH-stretch Fermi resonance in small water clusters.

A novel Raman jet-spectrometer is used to study the Fermi resonance between the OH bending overtone and OH stretching fundamental in small cyclic water clusters (H2O)n with n = 3, 4, 5. The new setup features a recirculating vacuum system which reduces the gas consumption by 2 to 3 orders of magnitude and enables long-term measurements of very weak Raman signals. Raman spectra measured from highly diluted expansions with unprecedented signal-to-noise ratio are presented and cluster-specific intensity ratios and effective coupling constants are derived using Markov-Chain Monte-Carlo methods, yielding a high probability for an almost "perfect" resonance for the tetramer and pentamer, i.e. a close frequency match of bend overtone and stretch fundamental with intensity ratios close to 1, but a larger coupling constant for the trimer, with best estimates close to W5 ≲ 50 cm-1 < W4 ≲ 60 cm-1 < W3 ≈ 65 cm-1.

Salmonella Saintpaul outbreak associated with cantaloupe consumption, the United Kingdom and Portugal, September to November 2023.

In September 2023, the UK Health Security Agency identified cases of Salmonella Saintpaul distributed across England, Scotland, and Wales, all with very low genetic diversity. Additional cases were identified in Portugal following an alert raised by the United Kingdom. Ninety-eight cases with a similar genetic sequence were identified, 93 in the United Kingdom and 5 in Portugal, of which 46% were aged under 10years. Cases formed a phylogenetic cluster with a maximum distance of six single nucleotide polymorphisms (SNPs) and average of less than one SNP between isolates. An outbreak investigation was undertaken, including a case-control study. Among the 25 UK cases included in this study, 13 reported blood in stool and 5 were hospitalized. One hundred controls were recruited via a market research panel using frequency matching for age. Multivariable logistic regression analysis of food exposures in cases and controls identified a strong association with cantaloupe consumption (adjusted odds ratio: 14.22; 95% confidence interval: 2.83-71.43; p-value: 0.001). This outbreak, together with other recent national and international incidents, points to an increase in identifications of large outbreaks of Salmonella linked to melon consumption. We recommend detailed questioning and triangulation of information sources to delineate consumption of specific fruit varieties during Salmonella outbreaks.

Two-axis multiple masses resonator with frequency and Q-factor matching

This paper reports a design and experimental results of a two-axis symmetric dynamically balanced resonator based on a triple mass system, whose frequency and Q-factor can be independently tuned. Two dynamically equivalent proof masses are connected by four coupling springs, and four coupling proof masses are implemented between them. The frequency and Q-factor of the anti-phase modes can be tuned independently of each other. The frequency is tuned by electrostatically softening the suspensions stiffness, and the Q-factor is adjusted by controlling the squeeze film damping through the mode coupling between the anti-phase and in-phase modes. The changes of frequency and mode coupling under different DC bias tunings are studied by FEA, which reveals the modification of the suspension stiffness only decreases the frequency and the modification of the inner stiffness of the coupling proof masses exerts a large effect on the mode shape, i.e. Q-factor, while a minor effect on the frequency. The as-fabricated frequency and Q-factor mismatches were evaluated as 5% and 7.7% in a fabricated device, respectively. A large adjustment of the Q-factor by 21% was observed by adding a 27 V DC voltage on the tuning electrodes inside the coupling proof masses, while the frequency was only decreased by as small as 810 ppm. A mode matching was achieved by electrostatic softening the suspensions of both main proof masses. Thanks to the decoupling between frequency and Q-factor, a frequency matching under 10 ppm and a Q-factor matching under 650 ppm were experimentally proved.