A Method to Achieve High Dynamic Range in a CMOS Image Sensor Using Interleaved Row Readout

©2022 The Author(s). This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see https://creativecommons.org/licenses/by/4.0/We present a readout scheme for CMOS image sensors that can be used to achieve arbitrarily high dynamic range (HDR) in principle. The linear full well capacity (LFWC) in high signal regions was extended 50 times from 20 to 984 ke − via an interlaced row-wise readout order, while the noise floor remained unchanged in low signal regions, resulting in a 34-dB increase in DR. The peak signal-to-noise ratio (PSNR) is increased in a continuous fashion from 43 to 60 dB. This was achieved by summing user-selected rows that were read out multiple times. Centroiding uncertainties were lowered when template-fitting a projected pattern, compared to the standard readout scheme. Example applications are aimed at scientific imaging due to the linearity and PSNR increase.Peer reviewe

Incoherent light in tapered graded-index fibre: a study of transmission and modal noise

© 2022 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license, http://creativecommons.org/licenses/by/4.0/We investigated the impact of taper length on light transmission through tapered graded-index fibres. We tested commercial fibres from Thorlabs and a custom graded-index fibre using both coherent and incoherent light sources. Our experimental results show optimum performance for taper transition lengths of 25 mm, although our simulations suggest further improvement may be possible for even shorter transition lengths. We also measured the modal noise power fluctuations caused by bending the fibre. Here, we observe that the custom fibre tapers have the highest transmission but suffer from the most modal noise. Accordingly, we find that the commercial graded-index fibre tapers promise practical usage as a beam mode-field converter, as they have lower power fluctuations but retain relatively high transmission if compared to commercial small core step-index fibre.Peer reviewe

Transmission properties of tapered optical fibres: Simulations and experimental measurements

© 2021 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license. https://creativecommons.org/licenses/by-nc-nd/4.0/We measured the transmission of tapered and untapered optical fibres as a function of input beam numerical aperture at 635 nm. The tapered fibres were fabricated with an adiabatic tapering process from graded and step-index fibres with 50 m core diameters to form a 100 mm long taper with 5:1 taper ratio. We tested tapered graded-index and step-index fibres fabricated from commercial Thorlabs products and a custom graded-index taper. The 5:1 tapered graded-index fibre can give a transmission greater than 0.4 for Thorlabs and 0.6 for the custom taper. We simulated the transmission of the tapered fibres and found reasonable agreement with the measured graded-index tapered fibre results across the numerical aperture range of interest. Experimentally, step-index tapered fibres performed relative poorly and considerably below modelling expectations. Based on our examinations this arises because the properties of step-index fibre were not robust to the tapering process. Suitably tapered graded-index fibres may offer a new route for efficient focal ratio reduction of fibre optic signals, e.g., in fibre-fed spectrographs, though we stress that our measurements have been limited to monochromatic light in this work.Peer reviewe

Testosterone differentially regulates targets of lipid and glucose metabolism in liver, muscle and adipose tissues of the testicular feminised mouse

Purpose: Testosterone deficiency is commonly associated with obesity, metabolic syndrome, type 2 diabetes and their clinical consequences - hepatic steatosis and atherosclerosis. The testicular feminised (tfm) mouse (non-functional androgen receptor and low testosterone) develops fatty liver and aortic lipid streaks on a high-fat diet whereas androgen replete XY littermate controls do not. Testosterone replacement ameliorates these effects, although the underlying mechanisms remain unknown. Methods: We compared the influence of testosterone on the expression of regulatory targets of glucose, cholesterol and lipid metabolism in muscle, liver, abdominal subcutaneous (SAT) and visceral adipose tissue (VAT). Results: Tfm mice displayed significantly reduced GLUT4 in muscle and glycolytic enzymes in muscle, liver and SAT but not VAT. Lipoprotein lipase required for fatty acid uptake was only reduced in SAT, enzymes of fatty acid synthesis were increased. Stearoyl-CoA desaturase-1 that catalyses oleic acid synthesis and is associated with insulin resistance was increased in VAT and cholesterol efflux components (ABCA1, apoE) were decreased. Master regulator nuclear receptors involved in metabolism:- Liver X receptor expression was suppressed in all tissues except VAT whereas PPARγ was lower in SAT and VAT and PPARα only in SAT. Testosterone replacement improved the expression (androgen receptor independent) of some targets but not all. Conclusion: These exploratory data suggest that androgen deficiency may reduce the buffering capability for glucose uptake and utilisation in SAT and muscle and fatty acids in SAT. This would lead to an overspill and uptake of excess glucose and triglycerides into VAT, liver and arterial walls

Mitigating Modal Noise in Multimode Circular Fibres by Optical Agitation using a Galvanometer

© 2024 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/Modal noise appears due to the non-uniform and unstable distribution of light intensity among the finite number of modes in multimode fibres. It is an important limiting factor in measuring radial velocity precisely by fibre-fed high-resolution spectrographs. The problem can become particularly severe as the fibre's core become smaller and the number of modes that can propagate reduces. Thus, mitigating modal noise in relatively small core fibres still remains a challenge. We present here a novel technique to suppress modal noise. Two movable mirrors in the form of a galvanometer reimage the mode-pattern of an input fibre to an output fibre. The mixing of modes coupled to the output fibre can be controlled by the movement of mirrors applying two sinusoidal signals through a voltage generator. We test the technique for four multimode circular fibres: 10 and 50 micron step-index, 50 micron graded-index, and a combination of 50 micron graded-index and 5:1 tapered fibres (GI50t). We present the results of mode suppression both in terms of the direct image of the output fibre and spectrum of white light obtained with the high-resolution spectrograph. We found that the galvanometer mitigated modal noise in all the tested fibres, but was most useful for smaller core fibres. However, there is a trade-off between the modal noise reduction and light-loss. The GI50t provides the best result with about 60% mitigation of modal noise at a cost of about 5% output light-loss. Our solution is easy to use and can be implemented in fibre-fed spectrographs.Peer reviewe

Feedback and focus: Exploring post-secondary students’ perceptions of feedback, mindfulness, and stress

Addressing feedback-associated stress as a barrier to learning is increasingly relevant to student success and well-being. Mindfulness practices support stress management for students during the academic feedback process. Even if students receive high-quality feedback, the receiving end of feedback can be stressful, perhaps raising feelings of anxiety, confusion, or inadequacy. Feedback literacy and mindfulness practices complement one another. Mindfulness can potentially support feedback literacy by focusing one’s attention on the tasks needed to address feedback, instead of being distracted by emotions triggered by feedback. This study, comprised of an online survey (n = 237) and focus groups (n = 6), assesses post-secondary students’ perceptions concerning feedback literacy, mindfulness, and stress, and their thoughts about digital mindfulness tools intended to support students experiencing feedback-associated stress. Recruitment of students was from courses in Health Sciences, Medical Sciences, Media Studies, and Law. The survey data demonstrate that students with greater mindfulness have significantly greater feedback literacy as well as lower stress. Focus group data shows that a broad range of affective and behavioral responses are shaped by students’ perceptions of their abilities, circumstances, and feedback itself. Although students expressed familiarity with mindfulness practices, few considered explicitly linking mindfulness to their feedback process. Nevertheless, students expressed interest regarding the development of digital mindfulness tools to alleviate feedback-associated stress and offered recommendations for implementation

Sirolimus for pediatric cervicofacial lymphatic malformation: A systematic review and meta-analysis

Objective This study is a systematic review and meta-analysis of the efficacy and safety of sirolimus in the management of pediatric cervicofacial lymphatic malformations (LMs). Data Sources EMBASE, Medline, Scopus, and Cochrane databases were searched, along with the reference list of all included articles. Review Methods The study protocol was registered with PROSPERO and a systematic literature search strategy was designed and conducted with the aid of a medical librarian. All studies including case reports were included, with pooled analysis of raw data. A meta-analysis was conducted of magnetic resonance imaging (MRI), clinical, and airway outcomes. Results Thirteen case series and five individual case reports were included. Meta-analysis showed 78% (95% CI 57%–94%) of 62 patients had a reduction in LM volume, on MRI criteria, by 20% or more, and 32% (95% CI 11%–57%) had a reduction of 50% or more. Further meta-analysis showed 97% (95% CI 88%–100%) of 78 patients reported some clinical improvement on sirolimus. Sirolimus may be of particular value in management of airway LMs; out of 27 tracheostomy-dependent patients, meta-analysis showed 33% (95% CI 1%–78%) were decannulated after starting sirolimus. Individual patient meta-analysis on 24 individuals showed a statistically significant better response to sirolimus when initiated under the age of 2 years. Conclusion This review and meta-analysis support the efficacy of sirolimus in pediatric LMs of the head, neck, and airway. A large multi-center trial is needed to further explore its role and limitations. Laryngoscope, 134:2038–2047, 202

A Method to Achieve High Dynamic Range in a CMOS Image Sensor Using Interleaved Row Readout

We present a readout scheme for CMOS image sensors that can be used to achieve arbitrarily high dynamic range (HDR) in principle. The linear full well capacity (LFWC) in high signal regions was extended 50 times from 20 ke− to 984 ke− via an interlaced row-wise readout order, whilst the noise floor remained unchanged in low signal regions, resulting in a 34 dB increase in DR. The peak signal-to-noise ratio (PSNR) is increased in a continuous fashion from 43 dB to 60 dB. This was achieved by summing user-selected rows which were read out multiple times. Centroiding uncertainties were lowered when template-fitting a projected pattern, compared to the standard readout scheme. Example applications are aimed at scientific imaging due to the linearity and PSNR increase

Metabolic phenotype of male obesity-related secondary hypogonadism pre-replacementand post-replacement therapy with intra-muscular testosterone undecanoate therapy

Aim: To explore the metabolic phenotype of obesity-related Secondary Hypogonadism (SH) in men pre- and post-replacement therapy with long-acting intramuscular (IM) testosterone undecanoate (TU). Methods: A prospective observational pilot study on metabolic effects of TU IM in male obesity-related SH (Hypogonadal [HG] group, n=13), including baseline comparisons with controls (Eugonadal [EG] group, n=15). Half the subjects (n=7 in each group) had Type 2 Diabetes Mellitus (T2D). Baseline metabolic assessment on Human Metabolism Research Unit: fasting blood samples; BodPod (body composition), and; whole-body indirect calorimetry. The HG group was treated with TU IM therapy for 6-29 months (mean 14.8-months [SD 8.7]), and assessment at the Human Metabolism Research Unit repeated. T-test comparisons were performed between baseline and follow-up data (HG group), and between baseline data (HG and EG groups). Data reported as mean (SD). Results: Overall, TU IM therapy resulted in a statistically significant improvement in HbA1C (9mmol/mol, P=0.03), with 52% improvement in HOMA%B. Improvement in glycaemic control was driven by the HG subgroup with T2D, with 18mmol/mol [P=0.02] improvement in HbA1C. Following TU IM therapy, there was a statistically significant reduction in fat mass (3.5Kg, P=0.03) and increase in lean body mass (2.9Kg, P=0.03). Lipid profiles and energy expenditure were unchanged following TU IM therapy. Comparisons between baseline data for HG and EG groups were equivalent apart from differences in testosterone, SHBG and BMR. Conclusion: In men with obesity-related SH (including a subgroup with T2D), TU IM therapy improved glycaemic control, beta cell function and body composition