High-resolution X-Ray imaging of small animal samples based on Commercial-Off-The-Shelf CMOS image sensors.

 An automated system for acquiring microscopic-resolution radiographic images of biological samples was developed. Mass-produced, low-cost, and easily automated components were used, such as Commercial-Off-The-Self CMOS image sensors (CIS), stepper motors, and control boards based on Arduino and RaspberryPi. System configuration, imaging protocols, and Image processing (filtering and stitching) were defined to obtain high-resolution images and for successful computational image reconstruction. Radiographic images were obtained for animal samples including the widely used animal models zebrafish (Danio rerio) and the fruit-fly (Drosophila melanogaster), as well as other small animal samples. The use of phosphotungstic acid (PTA) as a contrast agent was also studied. Radiographic images with resolutions of up to (7±0.6)µm were obtained, making this system comparable to commercial ones. This work constitutes a starting point for the development of more complex systems such as X-ray attenuation micro-tomography systems based on low-cost off-the-shelf technology. It will also bring the possibility to expand the studies that can be carried out with small animal models at many institutions (mostly those working on tight budgets), particularly those on the effects of ionizing radiation and absorption of heavy metal contaminants in animal tissues.

Programa de Acompañamiento del Sueño en la Infancia con Terapia Ocupacional durante la pandemia por COVID-19 / Program to Support Child Sleep from the Occupational Therapy Perspective during the COVID-19 pandemic

Introducción. Se describen los resultados preliminares del Programa de Acompañamiento al Sueño en la Infancia desde Terapia Ocupacional (PASITO) en niños y niñas con trastornos del neurodesarrollo (NN-TND), de 3 a 10 años, y con insomnio; realizado entre junio de 2020 y septiembre de 2021. Población y métodos. Estudio cuasiexperimental de preintervención y posintervención con un grupo de intervención y otro grupo de control, medido por el Cuestionario de Hábitos de Sueño (CHS) y el Diario de Sueño (DS). Resultados. Participaron 22 NN-TND, 8 en el grupo control. El puntaje total del CHS del grupo de intervención mejoró (p <0,001) de 54,9 (DE 5,5) a 48,4 (DE 4,5) y se acercó al rango de referencia 42,6 (DE 4,9). El DS evidenció aumento en duración, adelanto de fase de sueño y reducción en cantidad de despertares. Conclusión. Estos resultados provisorios y favorables muestran que PASITO podría ser una intervención posible para dificultades del sueño en NN-TND

Introduction. Here we describe the interim results of the Program to Support Child Sleep from the Occupational Therapy Perspective (Programa de Acompañamiento al Sueño en la Infancia desde Terapia Ocupacional, PASITO) for children with neurodevelopmental disorders (NDDs) aged 3­10 years with insomnia, conducted between June 2020 and September 2021. Population and methods. Pre- and post-intervention quasi-experiment in an intervention group and a control group using the Sleep Habits Questionnaire (SHQ) and the Consensus Sleep Diary (CSD). Results. A total of 22 children with NDDs participated, 8 in the control group. The overall SHQ score for the intervention group improved (p < 0.001) from 54.9 (SD: 5.5) to 48.4 (SD: 4.5) and moved closer to the reference range of 42.6 (SD: 4.9). The CSD showed an increased sleep duration, earlier sleep onset, and fewer night wakings. Conclusion. These interim favorable results demonstrate that the PASITO may be a possible intervention to manage sleep problems in children with NDDs.

Program to Support Child Sleep from the Occupational Therapy Perspective during the COVID-19 pandemic. / Programa de Acompañamiento del Sueño en la Infancia con Terapia Ocupacional durante la pandemia por COVID-19.

Introduction. Here we describe the interim results of the Program to Support Child Sleep from the Occupational Therapy Perspective (Programa de Acompañamiento al Sueño en la Infancia desde Terapia Ocupacional, PASITO) for children with neurodevelopmental disorders (NDDs) aged 3-10 years with insomnia, conducted between June 2020 and September 2021. Population and methods. Pre- and post-intervention quasi-experiment in an intervention group and a control group using the Sleep Habits Questionnaire (SHQ) and the Consensus Sleep Diary (CSD). Results. A total of 22 children with NDDs participated, 8 in the control group. The overall SHQ score for the intervention group improved (p < 0.001) from 54.9 (SD: 5.5) to 48.4 (SD: 4.5) and moved closer to the reference range of 42.6 (SD: 4.9). The CSD showed an increased sleep duration, earlier sleep onset, and fewer night wakings. Conclusion. These interim favorable results demonstrate that the PASITO may be a possible intervention to manage sleep problems in children with NDDs.

Introducción. Se describen los resultados preliminares del Programa de Acompañamiento al Sueño en la Infancia desde Terapia Ocupacional (PASITO) en niños y niñas con trastornos del neurodesarrollo (NN-TND), de 3 a 10 años, y con insomnio; realizado entre junio de 2020 y septiembre de 2021. Población y métodos. Estudio cuasiexperimental de preintervención y posintervención con un grupo de intervención y otro grupo de control, medido por el Cuestionario de Hábitos de Sueño (CHS) y el Diario de Sueño (DS). Resultados. Participaron 22 NN-TND, 8 en el grupo control. El puntaje total del CHS del grupo de intervención mejoró (p <0,001) de 54,9 (DE 5,5) a 48,4 (DE 4,5) y se acercó al rango de referencia 42,6 (DE 4,9). El DS evidenció aumento en duración, adelanto de fase de sueño y reducción en cantidad de despertares. Conclusión. Estos resultados provisorios y favorables muestran que PASITO podría ser una intervención posible para dificultades del sueño en NN-TND.

Multiplexed Readout for an Experiment with a Large Number of Channels Using Single-Electron Sensitivity Skipper-CCDs.

This paper presents the implementation of a multiplexed analog readout electronics system that can achieve single-electron counting using Skipper-CCDs with non-destructive readout. The proposed system allows the best performance of the sensors to be maintained, with sub-electron noise-level operation, while maintaining low-bandwidth data transfer, a minimum number of analog-to-digital converters (ADC) and low disk storage requirement with zero added multiplexing time, even for the simultaneous operation of thousands of channels. These features are possible with a combination of analog charge pile-up, sample and hold circuits and analog multiplexing. The implementation also aims to use the minimum number of components in circuits to keep compatibility with high-channel-density experiments using Skipper-CCDs for low-threshold particle detection applications. Performance details and experimental results using a sensor with 16 output stages are presented along with a review of the circuit design considerations.

Neutron-gamma dosimetry for BNCT using field oxide transistors with gadolinium oxide as neutron converter layer.

PURPOSE: A new type of electronic dosimeter is presented, capable of discerning between the doses of gamma photons and neutrons in a mixed beam as found in boron neutron capture therapy (BNCT). We introduce a real-time dosimeter based on a thick gate field oxide field effect transistor (FOXFET) covered with a neutron converter layer containing gadolinium. METHODS: To sensitize the FOXFET dosimeter to neutron fluxes, a converter layer containing gadolinium oxide particles embedded in photoresines was deposited over the sensor surface. Mixed neutron-gamma field configurations with different neutron energy spectra were used to assess the FOXFET response, considering different thicknesses of the neutron converter layer. RESULTS: The total gamma sensitivity of the devices resulted to be 43 mV/Gy. The responses of sensors with different converter layer thicknesses irradiated with different neutron spectra are simulated using GEANT4 code. The response to photons is not significantly modified with thin conversion layers when used in water medium. CONCLUSIONS: A real-time dosimeter comprising a pair of FOXFET sensors-only one of them with a gadolinium neutron converter layer-allows the simultaneous measurement of gamma dose and neutron flux during BNCT irradiations.

A Gadolinium Metal-Organic Framework Film as a Converter Layer for Neutron Detection.

Metal-organic frameworks (MOFs) are known for their versatility in terms of their crystalline structure, porosity, resistance to temperature, radiation damage, and luminescence among others. Gadolinium (Gd) is one of the elements with the highest reported cross-section for low energy neutron capture, producing internal conversion electrons and γ rays as a result of the neutron absorption. The development of Gd-BTC films (BTC=1,3,5-benzenetricarboxylate) is shown that were deposited on Si and Al substrates by airbrushing, and characterized by profilometry, Raman, EDX and X-ray diffraction. Radiation damage, thermal decomposition and neutron absorption of these films were studied as well. Gd-BTC films were attached to CMOS devices (Complementary Metal-Oxide-Semiconductor), which are sensible to the internal conversion electrons, in order to build a neutron detector. The devices Gd-BTC/CMOS could selectively detect neutrons in the presence of γ rays with a thermal neutron detection efficiency of 3.3±0.1 %, a signal to noise ratio of 6 : 1, and were suitable to obtain images.

Self-aligning CMOS photodetector sensor for application on an NDB-based optical encoder.

In this work, a complementary metal-oxide-semiconductor (CMOS) photodetector specifically designed to be used in a non-diffracting-beam (NDB) optical encoder is introduced. The sensor is aimed to address the critical alignment of the NDB-based optical encoder head and consists of a hexagonal array of photodiodes that can be interconnected among themselves. The photodiodes' interconnection is configured by means of static random access memory (SRAM) cells and transistors that operate as configurable connection switches between each photodiode and three of its neighbor photodiodes. This feature of the photodetector makes it possible to implement a search algorithm in order to find the photodiode where the NDB center impinges and then configure the appropriate detectivity pattern centered on that photodiode. It is shown that the new sensor design remarkably simplifies the alignment of the system.

Performance of an optical encoder based on a nondiffractive beam implemented with a specific photodetection integrated circuit and a diffractive optical element.

In this paper, we study the incremental signal produced by an optical encoder based on a nondiffractive beam (NDB). The NDB is generated by means of a diffractive optical element (DOE). The detection system is composed by an application specific integrated circuit (ASIC) sensor. The sensor consists of an array of eight concentric annular photodiodes, each one provided with a programmable gain amplifier. In this way, the system is able to synthesize a nonuniform detectivity. The contrast, amplitude, and harmonic content of the sinusoidal output signal are analyzed. The influence of the cross talk among the annular photodiodes is placed in evidence through the dependence of the signal contrast on the wavelength.