Performance of Neural Networks in Source Localization using Artificial Lateral Line Sensor Configurations

Artificial lateral lines (ALL) are used to detect the movement and locations of sources underwater, and are based on the lateral line organ found in fish and amphibians. Experiments have been performed to evaluate if the localization performance of neural networks, trained on simulated ALL sensor data, can be improved through adjustments of the internal ALL sensor positions. A Cramér-Rao lower bound analysis was performed on a subset of handpicked sensor configurations to estimate the likely performance of various configurations. The best and worst configurations were used to generate simulated datasets with which extreme learning machines (ELMs) and convolutional neural networks (CNNs) were trained and tested on their location accuracy. Simulated datasets consisted of two sources in a three-dimensional basin and the sensor readings of 16 ALL sensors. Results show that the best performing configuration consists of improved ELM and CNN localization performances, while also demonstrating that ELMs are capable of localizing multiple sources in three-dimensional aquatic environments, with comparable if not better results than CNNs

Subacute neurological deficits and respiratory insufficiency due to intrathecal methotrexate

BACKGROUND AND AIM: We present a case of a 22-year-old male diagnosed with B-cell acute lymphoblastic leukemia who received intrathecal (IT) methotrexate (MTX) in addition to his systemic chemotherapy regime. During induction treatment, he presented with a rapidly progressive bilateral paresis, anarthria, and respiratory insufficiency requiring intubation. The brain magnetic resonance imaging showed bilateral lesions with diffusion restriction of the corona radiata/centrum semi-ovale without other abnormalities. He recovered spontaneously without neurological sequelae. The clinical course combined with the radiological findings is suspect for an IT-MTX-induced leukoencephalopathy. RELEVANCE FOR PATIENTS: Although neurological deficits after IT-MTX are rare and in most cases self-limiting, it should be recognized as a cause for rapid neurological decline after excluding other causes

Compressive 3D ultrasound imaging using a single sensor

Three-dimensional ultrasound is a powerful imaging technique, but it requires thousands of sensors and complex hardware. Very recently, the discovery of compressive sensing has shown that the signal structure can be exploited to reduce the burden posed by traditional sensing requirements. In this spirit, we have designed a simple ultrasound imaging device that can perform three-dimensional imaging using just a single ultrasound sensor. Our device makes a compressed measurement of the spatial ultrasound field using a plastic aperture mask placed in front of the ultrasound sensor. The aperture mask ensures that every pixel in the image is uniquely identifiable in the compressed measurement. We demonstrate that this device can successfully image two structured objects placed in water. The need for just one sensor instead of thousands paves the way for cheaper, faster, simpler, and smaller sensing devices and possible new clinical applications

Acoustical compressive 3D imaging with a single sensor

3D ultrasound (US) requires expensive transducers comprising thousands of elements and complicated hardware. This complexity originates from the classical idea on spatial sampling requirements for US imaging. The discovery of compressive sensing allows to ease this sampling constraint, enabling smarter ways of recording the required information. Inspired by this work we introduce a US imager that can perform 3D imaging using one acoustic sensor. Our device sends and detects US waves through a random coding mask that enables unique signals at every voxel. Rotation of the mask allows for several compressed measurements. By knowing the voxel signals, a full 3D reconstruction of the object can be obtained, as we demonstrate in this work

Structured ultrasound microscopy

We present a form of acoustic microscopy, called Structured Ultrasound Microscopy (SUM). It creates a volumetric image by recording reflected echoes of ultrasound waves with a structured phase front using a moving single-element transducer and co

Adherence to preventive measures after SARS-CoV-2 vaccination and after awareness of antibody response in kidney transplant recipients in the Netherlands: a nationwide questionnaire studyResearch in context

Summary: Background: Kidney transplant recipients (KTRs) were advised to tightly adhere to government recommendations to curb the spread of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) because of a high risk of morbidity and mortality and decreased immunogenicity after vaccination. The aim of this study was to analyse the change in adherence to preventive measures after vaccination and awareness of antibody response, and to evaluate its effectiveness. Methods: In this large-scale, national questionnaire study, questionnaires were sent to 3531 KTRs enrolled in the Dutch RECOVAC studies, retrospectively asking for adherence to nine preventive measures on a 5-point Likert scale before and after SARS-CoV-2 vaccination and after awareness of antibody response. Blood samples were collected 28 days after the second vaccination. Antibody response was categorised as non-responder (≤50 BAU/mL), low-responder (>50 ≤ 300 BAU/mL) or high-responder (>300 BAU/mL), and shared with participants as a correlate of protection. Participants of whom demographics on sex and age, blood samples and completed questionnaires were available, were included. Our study took place between February 2021 and January 2022. The primary outcome of adherence before and after vaccination was assessed between August and October 2021 and compared via the Wilcoxon signed rank sum test. Logistic regression analysis was performed to estimate the association between antibody response and non-adherence, and adherence on acquiring SARS-CoV-2 infection. This study is registered at ClinicalTrials.gov (NCT04841785). Findings: In 2939 KTRs (83%) who completed the first questionnaire on adherence to preventive measures, adherence was higher before than after vaccination (4.56, IQR 4.11–4.78 and 4.22, IQR 3.67–4.67, p < 0.001). Adherence after awareness of antibody response was analysed in 2399 KTRs (82%) of whom also blood samples were available, containing 949 non-responders, 500 low-responders and 950 high-responders. Compared to non-responders, low- and high-responders reported higher non-adherence. Higher adherence was associated with lower infection rates before and after vaccination (OR 0.67 [0.51–0.91], p = 0.008 and OR 0.48 [0.28–0.86], p = 0.010). Interpretation: Adherence decreased after SARS-CoV-2 vaccination and in KTRs who were aware of a subsequent antibody response compared with those without. Preventive measures in this vulnerable group seem to be effective, regardless of vaccination status. This study starts a debate on sharing antibody results with the patient and future studies should elucidate whether decreased adherence in antibody responders is justified, also in view of future pandemics. Funding: The Netherlands Organization for Health Research and Development and the Dutch Kidney Foundation