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Time-domain diffuse correlation spectroscopy (TD-DCS) offers a novel approach to high-spatial resolution functional brain imaging based on the direct quantification of cerebral blood flow (CBF) changes in response to neural activity. However, the signal-to-noise ratio (SNR) offered by previous TD-DCS instruments remains a challenge to achieving the high temporal resolution needed to resolve perfusion changes during functional measurements. Here we present a next-generation optimized functional TD-DCS system that combines a custom 1,064 nm pulse-shaped, quasi transform-limited, amplified laser source with a high-resolution time-tagging system and superconducting nanowire single-photon detectors (SNSPDs). System characterization and optimization was conducted on homogenous and two-layer intralipid phantoms before performing functional CBF measurements in six human subjects. By acquiring CBF signals at over 5 Hz for a late gate start time of the temporal point spread function (TPSF) at 15 mm source-detector separation, we demonstrate for the first time the measurement of blood flow responses to breath-holding and functional tasks using TD-DCS.

The paper deals with the technological aspects of the construction site of Pompeii through the characterization of the mortars, focusing on the identification of raw materials, their supply areas, selection criteria and mixing techniques to evaluate the continuity and changes in the different construction phases. Thanks to a multidisciplinary protocol that integrates archaeological, architectural, minero-petrographic and geochemical analyses, the study reveals that the binders were obtained from burning limestones from Mt. Lattari, while the aggregates are compatible with products from the Somma-Vesuvius volcano. The mortars from the period before 62/63 CE are characterised by a careful selection and preparation of the raw material, while the mortars from the period after 62/63 CE indicate a less precise procedures, probably due to the urgent need for reconstruction after the earthquake. Despite these changes, the essential quality and hydraulic properties of the mortars remained intact, demonstrating the resilience of ancient building practises.

Abstract Speckle contrast optical spectroscopy (SCOS) is an emerging camera-based technique that can measure human cerebral blood flow (CBF) with high signal-to-noise ratio (SNR). At low photon flux levels typically encountered in human CBF measurements, camera noise and nonidealities could significantly impact SCOS measurement SNR and accuracy. Thus, a guide for characterizing, selecting, and optimizing a camera for SCOS measurements is crucial for the development of next-generation optical devices for monitoring human CBF and brain function. Here, we provide such a guide and illustrate it by evaluating three commercially available complementary metal–oxide–semiconductor cameras, considering a variety of factors including linearity, read noise, and quantization distortion. We show that some cameras that are well-suited for general intensity imaging could be challenged in accurately quantifying spatial contrast for SCOS. We then determine the optimal operating parameters for the preferred camera among the three and demonstrate measurement of human CBF with this selected low-cost camera. This work establishes a guideline for characterizing and selecting cameras as well as for determining optimal parameters for SCOS systems.

Objective: This pilot study aims to show the feasibility of noninvasive and real-time cerebral hemodynamic monitoring during carotid endarterectomy (CEA) via diffuse correlation spectroscopy (DCS) and near-infrared spectroscopy (NIRS). Methods: Cerebral blood flow index (CBFi) was measured unilaterally in seven patients and bilaterally in seventeen patients via DCS. In fourteen patients, hemoglobin oxygenation changes were measured bilaterally and simultaneously via NIRS. Cerebral autoregulation (CAR) and cerebrovascular resistance (CVR) were estimated using CBFi and arterial blood pressure data. Further, compensatory responses to the ipsilateral hemisphere were investigated at different contralateral stenosis levels. Results: Clamping of carotid arteries caused a sharp increase of CVR (~70%) and a marked decrease of ipsilateral CBFi (57%). From the initial drop, we observed partial recovery in CBFi, an increase of blood volume, and a reduction in CVR in the ipsilateral hemisphere. There were no significant changes in compensatory responses between different contralateral stenosis levels as CAR was intact in both hemispheres throughout the CEA phase. A comparison between hemispheric CBFi showed lower ipsilateral levels during the CEA and post-CEA phases (p < 0.001, 0.03). Conclusion: DCS alone or combined with NIRS is a useful monitoring technique for real-time assessment of cerebral hemodynamic changes and allows individualized strategies to improve cerebral perfusion during CEA by identifying different hemodynamic metrics.

Capacitive proximity sensing is widespread in our everyday life, but no sensor for biomedical optics takes advantage of this technology to monitor the probe attachment to the subject’s skin. In particular, when using optical monitoring devices, the capability to quantitatively measure the probe contact can significantly improve data quality and ensure the subject’s safety. We present a custom novel optical probe based on a flexible printed circuit board which integrates a capacitive contact sensor, 3D-printed optic fiber holders and an accelerometer sensor. The device can be effectively adopted during continuous monitoring optical measurements to detect contact quality, motion artifacts, probe detachment and ensure optimal signal quality.

Abstract Diffuse correlation spectroscopy (DCS) is an optical technique that can be used to characterize blood flow in tissue. The measurement of cerebral hemodynamics has arisen as a promising use case for DCS, though traditional implementations of DCS exhibit suboptimal signal-to-noise ratio (SNR) and cerebral sensitivity to make robust measurements of cerebral blood flow in adults. In this work, we present long wavelength, interferometric DCS (LW-iDCS), which combines the use of a longer illumination wavelength (1064 nm), multi-speckle, and interferometric detection, to improve both cerebral sensitivity and SNR. Through direct comparison with long wavelength DCS based on superconducting nanowire single photon detectors, we demonstrate an approximate 5× improvement in SNR over a single channel of LW-DCS in the measured blood flow signals in human subjects. We show equivalence of extracted blood flow between LW-DCS and LW-iDCS, and demonstrate the feasibility of LW-iDCS measured at 100 Hz at a source-detector separation of 3.5 cm. This improvement in performance has the potential to enable robust measurement of cerebral hemodynamics and unlock novel use cases for diffuse correlation spectroscopy.

RESUMO A temática do HIV ainda é permeada de estigmas e culpabilização de indivíduos por seus comportamentos. Políticas públicas, incluindo a de HIV/Aids, são baseadas em categorias políticas que geram efeitos simbólicos, reproduzindo ou enfrentando estigmas. A literatura afirma que Trabalhadores da Linha de Frente (TLF) mobilizam valores pessoais e profissionais nas interações com os usuários, que podem incluir categorias sociais ou políticas. Este artigo objetivou compreender como TLF operam tais categorias em contextos institucionais de ambiguidade, bem como analisar se suas percepções com relação às categorias de comportamento de risco e juventude estão em consonância com as políticas públicas. Foram analisadas 8 normativas e entrevistados 42 trabalhadores de 6 serviços de saúde. Os materiais foram codificados, as categorias oficiais foram comparadas, e as práticas, identificadas. As conclusões sugerem que as categorias sociais e políticas têm influência mútua. As categorias políticas ainda são legitimadas por meio de percepções sociais de normalidade e risco, especialmente ao lidar com populações prioritárias. As categorias sociais, operadas na implementação reforçam estigmas e julgamentos morais sobre alguns jovens, como os negros e pobres, as mães solteiras e a comunidade LGBTQIA+. Os serviços especializados utilizam mais as categorias políticas do que os serviços de atenção primária.

Abstract In premature infants with an extremely low gestational age (ELGA,

Currently, there is great interest in making neuroimaging widely accessible and thus expanding the sampling population for better understanding and preventing diseases. The use of wearable health devices has skyrocketed in recent years, allowing continuous assessment of physiological parameters in patients and research cohorts. While most health wearables monitor the heart, lungs and skeletal muscles, devices targeting the brain are currently lacking. To promote brain health in the general population, we developed a novel, low-cost wireless cerebral oximeter called FlexNIRS. The device has 4 LEDs and 3 photodiode detectors arranged in a symmetric geometry, which allows for a self-calibrated multi-distance method to recover cerebral hemoglobin oxygenation (SO2) at a rate of 100 Hz. The device is powered by a rechargeable battery and uses Bluetooth Low Energy (BLE) for wireless communication. We developed an Android application for portable data collection and real-time analysis and display. Characterization tests in phantoms and human participants show very low noise (noise-equivalent power

The majority of accidentally ingested foreign bodies is excreted from the gastrointestinal (GI) tract without any complications. Sometimes sharp foreign bodies – like chicken and fish bones – can lead to intestinal perforation and may present insidiously with a wide range of symptoms and, consequently, different diagnoses. We report the case of a 59-year-old woman presenting with fever and a 1-month history of vague abdominal pain. Computed tomography (CT) showed the presence of a hyperdense linear image close to the gastric antrum surrounded by a fluid collection and free peritoneal air. At laparotomy, a 4-cm rabbit bone fragment covered in inflamed tissue was detected next to a gastric wall perforation. Rabbit bone fragment ingestion, even if rarely reported, should not be underestimated as a possible cause of GI tract perforation.