A novel technique for measuring the reflection coefficient of sound absorbing materials

A new method to measure the acoustic behaviour of sound absorbing material in an impedance tube is presented. The method makes use of a novel particle velocity sensor, the microflown, and a microphone. The so-called p·u method is compared to three other methods of which the two microphone technique is well known. It is shown that the combination of a microphone and a microflown provides direct information on the acoustic impedance, the sound intensity and the sound energy density. The experimental results are compared to the results obtained with the conventional impedance tube measurements. To be able to repeat the measurements in a reliable way a well described test sample with a quarter-wave resonator is used. Furthermore it is shown that the viscothermal effects on the wave propagation are important, i.e. for the quarter-wave resonator and to a lesser extent for the impedance tube itself

A Three Dimensional Microflown

An integrated three dimensional acoustic particle velocity sensor is realized. The integration of multiple sensors on a single silicon die leads to improvements in terms of better a better reproducible sensor and a very small sensor to sensor distance allowing accurate single point measurements. Initial measurements performed show that three dimensional noise source finding is possible with this sensor

Sustained neural rhythms reveal endogenous oscillations supporting speech perception.

Rhythmic sensory or electrical stimulation will produce rhythmic brain responses. These rhythmic responses are often interpreted as endogenous neural oscillations aligned (or "entrained") to the stimulus rhythm. However, stimulus-aligned brain responses can also be explained as a sequence of evoked responses, which only appear regular due to the rhythmicity of the stimulus, without necessarily involving underlying neural oscillations. To distinguish evoked responses from true oscillatory activity, we tested whether rhythmic stimulation produces oscillatory responses which continue after the end of the stimulus. Such sustained effects provide evidence for true involvement of neural oscillations. In Experiment 1, we found that rhythmic intelligible, but not unintelligible speech produces oscillatory responses in magnetoencephalography (MEG) which outlast the stimulus at parietal sensors. In Experiment 2, we found that transcranial alternating current stimulation (tACS) leads to rhythmic fluctuations in speech perception outcomes after the end of electrical stimulation. We further report that the phase relation between electroencephalography (EEG) responses and rhythmic intelligible speech can predict the tACS phase that leads to most accurate speech perception. Together, we provide fundamental results for several lines of research-including neural entrainment and tACS-and reveal endogenous neural oscillations as a key underlying principle for speech perception

A Newton Solver for Micromorphic Computational Homogenization Enabling Multiscale Buckling Analysis of Pattern-Transforming Metamaterials

Mechanical metamaterials feature engineered microstructures designed to exhibit exotic, and often counter-intuitive, effective behaviour. Such a behaviour is often achieved through instability-induced transformations of the underlying periodic microstructure into one or multiple patterning modes. Due to a strong kinematic coupling of individual repeating microstructural cells, non-local behaviour and size effects emerge, which cannot easily be captured by classical homogenization schemes. In addition, the individual patterning modes can mutually interact in space as well as in time, while at the engineering scale the entire structure can buckle globally. For efficient numerical macroscale predictions, a micromorphic computational homogenization scheme has recently been developed. Although this framework is in principle capable of accounting for spatial and temporal interactions between individual patterning modes, its implementation relied on a gradient-based quasi-Newton solution technique. This solver is suboptimal because (i) it has sub-quadratic convergence, and (ii) the absence of Hessians does not allow for proper bifurcation analyses. Given that mechanical metamaterials often rely on controlled instabilities, these limitations are serious. To address them, a full Newton method is provided in detail in this paper. The construction of the macroscopic tangent operator is not straightforward due to specific model assumptions on the decomposition of the underlying displacement field pertinent to the micromorphic framework, involving orthogonality constraints. Analytical expressions for the first and second variation of the total potential energy are given, and the complete algorithm is listed. The developed methodology is demonstrated with two examples in which a competition between local and global buckling exists and where multiple patterning modes emerge.Comment: 34 pages, 17 figures, 1 table, 1 algorithm, abstract shortened to fulfill 1920 character limi

Word reading in monolingual and bilingual children with developmental language disorder

Many children with developmental language disorder (DLD) are reported to have word reading difficulties. However, previous research has focused mostly on monolingual children. The present study used two existing datasets to assess word reading outcomes of bilingual children with DLD. In Study 1, we compared word reading outcomes of monolingual and bilingual children with and without DLD (n = 93 monolingual DLD; n = 33 bilingual DLD, n = 42 monolingual TD; n = 74 bilingual TD). In Study 2, we compared those of monolingual (n = 91) and bilingual children with DLD (n = 51) on the basis of school record data. Findings from both studies show mean poor word reading outcomes and a high incidence of poor readers in the groups of children with DLD. Despite lower oral language outcomes of bilingual children in the mainstream language, reading outcomes of monolingual and bilingual children (with/without DLD) did not differ or outcomes were even better for the bilingual children. Overall, these findings indicate that DLD is a risk factor for word reading difficulties, while bilingualism is not

The effect of ozone exposure on the release of eicosanoids in guinea-pig BAL fluid in relation to cellular damage and inflammation

The observed effects after ozone exposure strongly depend on ozone concentration and exposure time. We hypothesized that depending on the O3 exposure protocol, mainly either an oxidant damage or an inflammation will determine the O3 toxicity. We compared two different ozone exposure protocols: an acute exposure (3 ppm 2 h) for studying the oxidant damage and an exposure (1 ppm 12 h) where an inflammatory component is also probably involved. We measured LDH activity and protein and albumin exudation as markers for cellular damage. After the acute exposure an increase in LDH activity was measured and after exposure to 1 ppm ozone for 12 h the exudation of protein and albumin was also enhanced. The histological examinations showed a neutrophilic inflammatory response only after exposure to 1 ppm ozone for 12 h. The acute exposure protocol resulted in an increased release of PGE2, PGD2, PGF2α and 6-ketoPGF1α whereas exposure to 1 ppm ozone for 12 h led to an additional release of LTB4. No effects were measured on the release of TxB2 and LTC4/D4/E4. These changed amounts of eicosanoids will probably contribute to the ozone-induced lung function changes

In-gas-cell laser ionization spectroscopy in the vicinity of 100Sn: Magnetic moments and mean-square charge radii of N=50-54 Ag

In-gas-cell laser ionization spectroscopy studies on the neutron deficient 97-101Ag isotopes have been performed with the LISOL setup. Magnetic dipole moments and mean-square charge radii have been determined for the first time with the exception of 101Ag, which was found in good agreement with previous experimental values. The reported results allow tentatively assigning the spin of 97,99Ag to 9/2 and confirming the presence of an isomeric state in these two isotopes, whose collapsed hyperfine structure suggests a spin of 1/2 . The effect of the N=50 shell closure is not only manifested in the magnetic moments but also in the evolution of the mean-square charge radii of the isotopes investigated, in accordance with the spherical droplet model predictions

Qualification of piezo-electric actuators for the MADMAX booster system at cryogenic temperatures and high magnetic fields

We report on the qualification of a piezo-based linear stage for the manipulation of positions of dielectric discs in the booster of the MADMAX axion dark matter search experiment. A first demonstrator of the piezo drives, specifically developed for MADMAX, was tested at room temperature as well as at cryogenic temperatures down to 4.5 K and inside strong magnetic fields up to 5.3 T. These qualification measurements prove that the piezo-based linear stage is suited for MADMAX and fulfills the requirements.Comment: 13 pages, 9 figures, 2 table

Association of histological features with laryngeal squamous cell carcinoma recurrences:a population-based study of 1502 patients in the Netherlands

BACKGROUND: Recurrences remain an important problem in laryngeal squamous cell carcinoma. Little has been described about histological characteristics of the primary laryngeal tumor that may be associated with recurrences. Identifying risk factors for recurrences might help in adapting treatment or follow-up. Using real-life population-based data, we aimed to identify histological features of the primary tumor associated with recurrences and overall survival. MATERIAL AND METHODS: Demographic, clinical and treatment information on all first primary invasive laryngeal tumors diagnosed in 2010–2014 (N = 3705) were extracted from the population-based nationwide Netherlands cancer registry (NCR) and linked to PALGA, the nationwide Dutch pathology registry, to obtain data on histological factors and recurrences. For a random 1502 patients histological information i.e., keratinization, perineural invasion (PNI+), vascular invasion (VI+), growth pattern, degree of differentiation, extracapsular spread (ECS+), cartilage- and bone invasion and extralaryngeal extension, was manually extracted from narrative pathology reports and analyzed for locoregional recurrence and overall survival using cox regression analysis. RESULTS: In total, 299 patients developed a locoregional recurrence and 555 patients died. Keratinization (HR = 0.96 (95%CI: 0.68–1.34) p = 0.79), two or three adverse characteristics (PNI+, VI+, non-cohesive growth) (HR = 1.38 (95% CI: 0.63–3.01) p = 0.42), and ECS+ (HR = 1.38 (95% CI: 0.48–4.02) p = 0.55) were not associated to recurrence. For death, also no significant association was found. CONCLUSION: In this population-based real-life dataset on laryngeal carcinoma in the Netherlands, histological factors were not associated with locoregional recurrences or overall survival, but future studies should investigate the role of these features in treatment decisions. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12885-022-09533-0

Hospital-acquired sinusitis is a common cause of fever of unknown origin in orotracheally intubated critically ill patients

INTRODUCTION: Sinusitis is a well recognised but insufficiently understood complication of critical illness. It has been linked to nasotracheal intubation, but its occurrence after orotracheal intubation is less clear. We studied the incidence of sinusitis in patients with fever of unknown origin (FUO) in our intensive care unit with the aim of establishing a protocol that would be applicable in everyday clinical practice. METHODS: Sinus X-rays (SXRs) were performed in all patients with fever for which an initial screening (physical examination, microbiological cultures and chest X-ray) revealed no obvious cause. All patients were followed with a predefined protocol, including antral drainage in all patients with abnormal or equivocal results on their SXR. RESULTS: Initial screening revealed probable causes of fever in 153 of 351 patients (43.6%). SXRs were taken in the other 198 patients (56.4%); 129 had obvious or equivocal abnormalities. Sinus drainage revealed purulent material and positive cultures (predominantly Pseudomonas and Klebsiella species) in 84 patients. Final diagnosis for the cause of fever in all 351 patients based on X-ray results, microbiological cultures, and clinical response to sinus drainage indicated sinusitis as the sole cause of fever in 57 (16.2%) and as contributing factor in 48 (13.8%) patients with FUO. This will underestimate the actual incidence because SXR and drainage were not performed in all patients. CONCLUSION: Physicians treating critically ill patients should be aware of the high risk of sinusitis and take appropriate preventive measures, including the removal of nasogastric tubes in patients requiring long-term mechanical ventilation. Routine investigation of FUO should include computed tomography scan, SXR or sinus ultrasonography, and drainage should be performed if any abnormalities are found