Rodent arena tracker (RAT): A machine vision rodent tracking camera and closed loop control system

Video tracking is an essential tool in rodent research. Here, we demonstrate a machine vision rodent tracking camera based on a low-cost, open-source, machine vision camera, the OpenMV Cam M7. We call our device the rodent arena tracker (RAT), and it is a pocket-sized machine vision-based position tracker. The RAT does not require a tethered computer to operate and costs about $120 per device to build. These features make the RAT scalable to large installations and accessible to research institutions and educational settings where budgets may be limited. The RAT processes incoming video in real-time at 15 Hz and save

Elective cancer surgery in COVID-19-free surgical pathways during the SARS-CoV-2 pandemic: An international, multicenter, comparative cohort study

PURPOSE As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19–free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19–free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19–free surgical pathways. Patients who underwent surgery within COVID-19–free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19–free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score–matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19–free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION Within available resources, dedicated COVID-19–free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

Elective Cancer Surgery in COVID-19-Free Surgical Pathways During the SARS-CoV-2 Pandemic: An International, Multicenter, Comparative Cohort Study.

PURPOSE: As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19-free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS: This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19-free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS: Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19-free surgical pathways. Patients who underwent surgery within COVID-19-free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19-free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score-matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19-free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION: Within available resources, dedicated COVID-19-free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

Digital Video Recorder for Raspberry PI cameras with Multi-Camera Synchronous Acquisition

Video acquisition and analysis has become an integral part of scientific research. Often, using multiple cameras with synchronized acquisition yields greater accuracy in video analytics. Several commercial video systems are available as turnkey solutions for the multi-camera synchronous acquisition. Costs of these systems, however, might constrain researchers and stifle innovative research. An open-source acquisition system would allow cost-effective testing of innovative research and making research prototypes. We present an open-source digital video recorder (DVR) system for the popular Raspberry PI camera. Our DVR is simple to setup and use whether for a single camera or multiple cameras. In the case of multiple cameras, the acquisition is synchronous. The DVR comes with a graphical user interface (GUI) which allows previewing the camera streams, setting of recording parameters, and associating ‘names’ to cameras. The acquisition code as well as the DVR GUI is written in Python. The open-source software also includes GUI for playback and tools for video annotations. The versatility of the DVR is demonstrated with life science applications involving monitoring laboratory mice and fruit-flies

Direct detection and time-locked subsampling applied to pulsed electron paramagnetic resonance imaging

The application of direct time-locked subsampling (TLSS) to Fourier transform electron paramagnetic resonance (FT-EPR) spectroscopy at radio frequencies (rf) is described. With conventional FT-EPR spectroscopy, the high Larmor frequencies (L)often necessitate the use of intermediate frequency (IF) stages to down convert the received free induction decay (FID) signal to a frequency that can be acquired with common data acquisition technology. However, our research focuses on in vivo studies, and consequently utilizes a FT-EPR system with a L<SUB>f</SUB> of 300 MHz. This relatively low frequency L<SUB>f</SUB>, in conjunction with the advent of bandpass sampling analog-to-digital conversion and signal processing technologies, has enabled us to omit the I<SUB>F</SUB> stage in our FT-EPR system. With this in mind, TLSS techniques have been developed to directly sample the 300 MHz FID signal at a sampling rate of 80 MHz providing a signal bandwidth of 20 MHz. The required modifications to the data acquisition and processing system specific to this application are described. Custom software developed to control the EPR system setup, acquire the signals, and post process the data, is outlined. Data was acquired applying both coherent averaging and stochastic excitation sequences. The results of these experiments demonstrate digital down conversion of the 300 MHz FID signal to quadrature baseband. Direct FID TLSS eliminates many noise sources common in EPR systems employing traditional analog receiver techniques, such as the IF mixer stage in single channel systems, and the quadrature baseband mixer stage in dual channel systems

Integration of digital signal processing technologies with pulsed electron paramagnetic resonance imaging

The integration of modern data acquisition and digital signal processing (DSP) technologies with Fourier transform electron paramagnetic resonance (FT-EPR) imaging at radiofrequencies (RF) is described. The FT-EPR system operates at a Larmor frequency (L<SUB>f</SUB>) of 300 MHz to facilitate in vivo studies. This relatively low frequency L<SUB>f</SUB>, in conjunction with our ~10 MHz signal bandwidth, enables the use of direct free induction decay time-locked subsampling (TLSS). This particular technique provides advantages by eliminating the traditional analog intermediate frequency downconversion stage along with the corresponding noise sources. TLSS also results in manageable sample rates that facilitate the design of DSP-based data acquisition and image processing platforms. More specifically, we utilize a high-speed field programmable gate array (FPGA) and a DSP processor to perform advanced real-time signal and image processing. The migration to a DSP-based configuration offers the benefits of improved EPR system performance, as well as increased adaptability to various EPR system configurations (i.e., software configurable systems instead of hardware reconfigurations). The required modifications to the FT-EPR system design are described, with focus on the addition of DSP technologies including the application-specific hardware, software, and firmware developed for the FPGA and DSP processor. The first results of using real-time DSP technologies in conjunction with direct detection bandpass sampling to implement EPR imaging at RF frequencies are presented