Model-Based Explainable Deep Learning for Light-Field Microscopy Imaging.

In modern neuroscience, observing the dynamics of large populations of neurons is a critical step of understanding how networks of neurons process information. Light-field microscopy (LFM) has emerged as a type of scanless, high-speed, three-dimensional (3D) imaging tool, particularly attractive for this purpose. Imaging neuronal activity using LFM calls for the development of novel computational approaches that fully exploit domain knowledge embedded in physics and optics models, as well as enabling high interpretability and transparency. To this end, we propose a model-based explainable deep learning approach for LFM. Different from purely data-driven methods, the proposed approach integrates wave-optics theory, sparse representation and non-linear optimization with the artificial neural network. In particular, the architecture of the proposed neural network is designed following precise signal and optimization models. Moreover, the network's parameters are learned from a training dataset using a novel training strategy that integrates layer-wise training with tailored knowledge distillation. Such design allows the network to take advantage of domain knowledge and learned new features. It combines the benefit of both model-based and learning-based methods, thereby contributing to superior interpretability, transparency and performance. By evaluating on both structural and functional LFM data obtained from scattering mammalian brain tissues, we demonstrate the capabilities of the proposed approach to achieve fast, robust 3D localization of neuron sources and accurate neural activity identification.

What Are the Care Needs of Families Experiencing Sudden Cardiac Arrest? A Survivor- and Family-Performed Systematic Review, Qualitative Meta-Synthesis, and Clinical Practice Recommendations.

INTRODUCTION: Cardiac arrest care systems are being designed and implemented to address patients', family members', and survivors' care needs. We conducted a systematic review and a meta-synthesis to understand family experiences and care needs during cardiac arrest care to create treatment recommendations. METHODS: We searched eight electronic databases to identify articles. Study findings were extracted, coded and synthesized. Confidence in the quality, coherence, relevance, and adequacy of data underpinning the resulting findings was assessed using GRADE-CERQual methods. RESULTS: In total 4181 studies were screened, and 39 met our inclusion criteria; these studies enrolled 215 survivors and 418 family participants-which includes both co-survivors and bereaved family members. From these studies findings and participant data we identified 5 major analytical themes: (1) When the crisis begins we must respond; (2) Anguish from uncertainty, we need to understand; (3) Partnering in care, we have much to offer; (4) The crisis surrounding the victim, ignore us, the family, no longer; (5) Our family's emergency is not over, now is when we need help the most. Confidence in the evidence statements are provided along with our review findings. DISCUSSION: The family experience of cardiac arrest care is often chaotic, distressing, complex and the aftereffects are long-lasting. Patient and family experiences could be improved for many people. High certainty family care needs identified in this review include rapid recognition and response, improved information sharing, more effective communication, supported presence and participation, or supported absence, and psychological aftercare.

The Clinical Frailty Scale for mortality prediction of old acutely admitted intensive care patients: a meta-analysis of individual patient-level data.

BACKGROUND: This large-scale analysis pools individual data about the Clinical Frailty Scale (CFS) to predict outcome in the intensive care unit (ICU). METHODS: A systematic search identified all clinical trials that used the CFS in the ICU (PubMed searched until 24th June 2020). All patients who were electively admitted were excluded. The primary outcome was ICU mortality. Regression models were estimated on the complete data set, and for missing data, multiple imputations were utilised. Cox models were adjusted for age, sex, and illness acuity score (SOFA, SAPS II or APACHE II). RESULTS: 12 studies from 30 countries with anonymised individualised patient data were included (n = 23,989 patients). In the univariate analysis for all patients, being frail (CFS ≥ 5) was associated with an increased risk of ICU mortality, but not after adjustment. In older patients (≥ 65 years) there was an independent association with ICU mortality both in the complete case analysis (HR 1.34 (95% CI 1.25-1.44), p < 0.0001) and in the multiple imputation analysis (HR 1.35 (95% CI 1.26-1.45), p < 0.0001, adjusted for SOFA). In older patients, being vulnerable (CFS 4) alone did not significantly differ from being frail. After adjustment, a CFS of 4-5, 6, and ≥ 7 was associated with a significantly worse outcome compared to CFS of 1-3. CONCLUSIONS: Being frail is associated with a significantly increased risk for ICU mortality in older patients, while being vulnerable alone did not significantly differ. New Frailty categories might reflect its "continuum" better and predict ICU outcome more accurately. TRIAL REGISTRATION: Open Science Framework (OSF: https://osf.io/8buwk/ ).

Leadership self-efficacy and nurses' aspiration to leadership: An evolutionary concept analysis.

BACKGROUND: The complex nature of leadership in nursing and healthcare requires a vast skill set. Leadership self-efficacy (LSE) has emerged as an important concept to support leadership development in the nursing literature. An analysis of LSE can clarify and inform strategies for leadership development among nurses. OBJECTIVE: To clarify the concept of LSE and understand how it relates to nurses' motivation and aspiration for formal leadership roles. METHOD: A concept analysis using Rodgers' evolutionary method identified attributes, antecedents, and consequences of LSE. Twenty-three articles published between 1993 and 2022 were analyzed following a Boolean search of four databases - Academic Search Complete, CINAHL, MEDLINE, and Scopus. RESULTS: LSE is an important element of nurses' aspiration to leadership. Leadership training, individual traits, and organizational support affect levels of LSE. When LSE is increased, job performance and nurses' motivation to take on formal leadership increase. CONCLUSION: The concept analysis further expands knowledge about factors that affect LSE. It provides data on how LSE can be harnessed to support leadership development and career aspiration for nurses. Developing and nurturing LSE among nurses may be key in promoting leadership career aspirations. Nurse leaders in practice, research, and academia can use this knowledge as a guide in leadership program development.

Prevalence and Characteristics of Cytomegalovirus Ocular Disease in Children: A Multi-Center Study.

Purpose: The objective of this study was to identify the prevalence of CMV ocular disease in children and to identify associated risk factors for ocular involvement. Design: Retrospective multicenter, cross-sectional study. Methods: Setting: Hospitalized patients screened for CMV viremia by PCR between 2005 and 2018 at four pediatric referral centers. Participants: Seven-hundred and ninety-three children showed CMV viremia (>135 copies/mL by polymerase chain reaction; PCR). Main Outcomes and Measures: (1) Occurrence of ophthalmologic examination. (2) Presence of CMV ocular disease, defined as retinitis, vasculitis, hemorrhage, optic nerve atrophy, or anterior uveitis in the setting of CMV viremia without other identifiable causes. Results: A total of 296/793 (37%) underwent ophthalmologic examination following CMV viremia. A total of23/296 patients (8%) had ocular symptoms prompting evaluation while the rest had eye exams for baseline screening unrelated to CMV viremia. Of these, 13 cases (4% of those with an eye exam) with ocular disease were identified (three congenital CMV, five severe combined immunodeficiency disorder (SCID) status post-stem cell transplantation, three hematologic malignancy status post-stem cell transplantation for two of them, one Evans syndrome status post-stem cell transplantation, and one medulloblastoma status post-bone marrow transplantation). No patients with solid organ transplantation developed CMV ocular disease in our cohort. Conclusion: CMV ocular disease was a rare occurrence in this cohort without an identifiable pattern across sub-groups. Excluding the three congenital CMV cases, nine out of ten patients with CMV ocular disease were status post-stem cell transplantation. We provide integrated screening guidelines based on the best available evidence for this rare condition.

Comparing synthetic refocusing to deconvolution for the extraction of neuronal calcium transients from light fields.

Significance: Light-field microscopy (LFM) enables fast, light-efficient, volumetric imaging of neuronal activity with calcium indicators. Calcium transients differ in temporal signal-to-noise ratio (tSNR) and spatial confinement when extracted from volumes reconstructed by different algorithms. Aim: We evaluated the capabilities and limitations of two light-field reconstruction algorithms for calcium fluorescence imaging. Approach: We acquired light-field image series from neurons either bulk-labeled or filled intracellularly with the red-emitting calcium dye CaSiR-1 in acute mouse brain slices. We compared the tSNR and spatial confinement of calcium signals extracted from volumes reconstructed with synthetic refocusing and Richardson-Lucy three-dimensional deconvolution with and without total variation regularization. Results: Both synthetic refocusing and Richardson-Lucy deconvolution resolved calcium signals from single cells and neuronal dendrites in three dimensions. Increasing deconvolution iteration number improved spatial confinement but reduced tSNR compared with synthetic refocusing. Volumetric light-field imaging did not decrease calcium signal tSNR compared with interleaved, widefield image series acquired in matched planes. Conclusions: LFM enables high-volume rate, volumetric imaging of calcium transients in single cell somata (bulk-labeled) and dendrites (intracellularly loaded). The trade-offs identified for tSNR, spatial confinement, and computational cost indicate which of synthetic refocusing or deconvolution can better realize the scientific requirements of future LFM calcium imaging applications.

Light-Field Microscopy for Optical Imaging of Neuronal Activity: When Model-Based Methods Meet Data-Driven Approaches.

Understanding how networks of neurons process information is one of the key challenges in modern neuroscience. A necessary step to achieve this goal is to be able to observe the dynamics of large populations of neurons over a large area of the brain. Light-field microscopy (LFM), a type of scanless microscope, is a particularly attractive candidate for high-speed three-dimensional (3D) imaging. It captures volumetric information in a single snapshot, allowing volumetric imaging at video frame-rates. Specific features of imaging neuronal activity using LFM call for the development of novel machine learning approaches that fully exploit priors embedded in physics and optics models. Signal processing theory and wave-optics theory could play a key role in filling this gap, and contribute to novel computational methods with enhanced interpretability and generalization by integrating model-driven and data-driven approaches. This paper is devoted to a comprehensive survey to state-of-the-art of computational methods for LFM, with a focus on model-based and data-driven approaches.

ASSESSMENT OF DISEASE RISK ASSOCIATED WITH POTENTIAL REMOVAL OF ANTHROPOGENIC BARRIERS TO MOJAVE DESERT TORTOISE (GOPHERUS AGASSIZII) POPULATION CONNECTIVITY.

The Mojave Desert tortoise (Gopherus agassizii), federally listed as threatened, has suffered habitat loss and fragmentation due to human activities. Upper respiratory tract disease (URTD), a documented health threat to desert tortoises, has been detected at the Large-Scale Translocation Study Site (LSTS) in southwestern Nevada, US, a fenced recipient site for translocated animals. Our study aimed to 1) estimate prevalence of URTD and Mycoplasma infection at LSTS and three nearby unfenced sites; 2) assess whether Mycoplasma infection status was associated with developing clinical signs of URTD; and 3) determine whether such an association differed between LSTS and unfenced areas. We sampled 421 tortoises in 2016 to describe the current status of these populations. We evaluated three clinical signs of URTD (nasal discharge, ocular discharge, nasal erosions) and determined individual infection status for Mycoplasma agassizii and Mycoplasma testudineum by quantitative PCR and enzyme-linked immunosorbent assay. In 2016, LSTS had the highest prevalence of M. agassizii (25.0%; 33/132), M. testudineum (3.0%; 4/132), and URTD clinical signs (18.9%; 25/132). Controlling for other factors, clinical sign(s) were positively associated with M. agassizii infection (odds ratio [OR]=7.7, P=0.001), and this effect was similar among study sites (P>0.99). There was no association with M. testudineum status (P=0.360). Of the 196 tortoises in a longitudinal comparison of 2011-14 with 2016, an estimated 3.2% converted from M. agassizii-negative to positive during the study period, and incidence was greater at LSTS (P=0.002). Conversion to positive M. agassizii status was associated with increased incidence of clinical signs in subsequent years (OR=11.1, P=0.018). While M. agassizii and URTD are present outside the LSTS, there is a possibility that incidence of Mycoplasma infection and URTD would increase outside LSTS if these populations were to reconnect. Population-level significance of this risk appears low, and any risk must be evaluated against the potential long-term benefits to population viability through increased connectivity.

Frailty inclusive care in acute and community-based settings: a systematic review protocol.

BACKGROUND: Frailty is a known risk factor for an array of adverse outcomes including more frequent and prolonged health services use and high health care costs. Aging of the population has implications for care provision across the care continuum, particularly for people living with frailty. Despite known risks associated with frailty, there has been limited research on care pathways that address the needs of persons living with frailty. Our study aims to review and examine, in a rigorous way, the quality of evidence for multi-component interventions and care pathways focused on frailty. METHODS: A comprehensive electronic search strategy will be used to identify studies that evaluate multi-component interventions or care pathways for persons living with frailty. The search strategy will include terms for frailty, multi-component interventions, effectiveness, and cost effectiveness applied to the following databases: MEDLINE (OVID), EMBASE (OVID), CINAHL (EBSCO), Cochrane Central Register of Controlled Trials (CENTRAL), and Cochrane Database of Systematic Reviews. An adapted search for Google Scholar and gray literature databases will also be used. References of included studies will be hand-searched for additional citations of frailty-inclusive care. Known experts and corresponding authors of identified articles will be contacted by email to identify further eligible studies. Risk of bias will be assessed using the Effective Public Health Practice Project Quality Assessment tool. Data will be extracted from eligible studies and it is anticipated that narrative analysis will be used. If studies with sufficient homogeneity are found, then pooled effects will be reported using meta-analysis. DISCUSSION: This review will appraise the evidence currently available on multi-component frailty interventions. Results will inform on clinical pathway development for people living with frailty across the care continuum and will guide future research to address gaps in the literature and areas in need of further development. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42020166733.

Herpesvirus surveillance and discovery in zoo-housed ruminants.

Gammaherpesvirus infections are ubiquitous in captive and free-ranging ruminants and are associated with a variety of clinical diseases ranging from subclinical or mild inflammatory syndromes to fatal diseases such as malignant catarrhal fever. Gammaherpesvirus infections have been fully characterized in only a few ruminant species, and the overall diversity, host range, and biologic effects of most are not known. This study investigated the presence and host distribution of gammaherpesviruses in ruminant species at two facilities, the San Diego Zoo and San Diego Zoo Safari Park. We tested antemortem (blood, nasal or oropharyngeal swabs) or postmortem (internal organs) samples from 715 healthy or diseased ruminants representing 96 species and subspecies, using a consensus-based herpesvirus PCR for a segment of the DNA polymerase (DPOL) gene. Among the 715 animals tested, 161 (22.5%) were PCR and sequencing positive for herpesvirus, while only 11 (6.83%) of the PCR positive animals showed clinical signs of malignant catarrhal fever. Forty-four DPOL genotypes were identified of which only 10 have been reported in GenBank. The data describe viral diversity within species and individuals, identify host ranges of potential new viruses, and address the proclivity and consequences of interspecies transmission during management practices in zoological parks. The discovery of new viruses with wide host ranges and presence of co-infection within individual animals also suggest that the evolutionary processes influencing Gammaherpesvirus diversity are more complex than previously recognized.

The Impact of Preoperative Frailty on the Clinical and Cost Outcomes of Adult Cardiac Surgery in Alberta, Canada: A Cohort Study.

BACKGROUND: There is limited information about the impact of frailty on public payer costs in cardiac surgery. This study aimed to determine quality-adjusted life-years (QALYs) and costs associated with preoperative frailty in patients referred for cardiac surgery. METHODS: We retrospectively compared costs of frailty in a cohort of 529 patients aged ≥ 50 years who were referred for nonemergent cardiac surgery in Alberta. Patients were screened preoperatively for frailty, defined as a score of 5 or greater on the Clinical Frailty Scale. The primary outcome measure was public payer costs attributable to frailty, calculated in a difference-in-difference (DID) model. RESULTS: The prevalence of frailty was 10% (n = 51; 95% confidence interval [CI], 7%-12%). Median (interquartile range) costs for frail patients were higher in the first year postsurgery ($200,709 [$146,177-$486,852] vs $147,730 [$100,674-$177,025]; P < 0.001) compared to nonfrail; the difference-in-difference attributable cost of frailty was $57,836 (95% CI, $-28,608-$144,280). At 1 year, frail patients had fewer QALYs realized compared to nonfrail patients (0.71 [0.57-0.77] vs 0.82 [0.75-0.86], P < 0.001), whereas QALYs gained were similar (0.02 [-0.02-0.05] vs 0.02 [0.00-0.04], P = 0.58, median difference 0.003 [95% CI, -0.01-0.02]) in frail and nonfrail patients. CONCLUSIONS: Frailty screening identified a population with greater impairment in quality-of-life and greater healthcare costs. Costs attributable to frailty represent opportunity costs that should be considered in future cardiac surgical services planning in the context of our aging population and the growing prevalence of frailty.

CONTEXTE: Il existe peu de renseignements concernant les répercussions de la fragilité sur les coûts pour les payeurs publics en chirurgie cardiaque. Cette étude visait à déterminer les années de vie pondérées par la qualité (QALY, pour Quality-Adjusted Life-Years) et les coûts associés à la fragilité préopératoire chez les patients dirigés vers un service de chirurgie cardiaque. MÉTHODOLOGIE: Nous avons comparé de façon rétrospective les coûts de la fragilité dans une cohorte de 529 patients âgés de 50 ans ou plus qui ont été dirigés vers un service de chirurgie cardiaque pour une intervention non urgente en Alberta. Un dépistage de la fragilité, définie comme un score de 5 ou plus à l'échelle CFS (Clinical Frailty Scale), a été effectué avant l'intervention. Le principal critère d'évaluation était le coût attribuable à la fragilité pour les payeurs publics, calculé selon un modèle d'écart des différences. RÉSULTATS: La prévalence de la fragilité a été de 10 % (n = 51; intervalle de confiance [IC] à 95 % : 7 à 12 %). Les coûts médians (écart interquartile) dans la première année suivant l'intervention chirurgicale ont été plus élevés chez les patients fragiles que chez les patients non fragiles (200 709 $ [146 177 $ à 486 852 $] contre 147 730 $ [100 674 $ à 177 025 $]; p < 0,001); le coût attribuable de la fragilité selon le modèle d'écart des différences a été de 57 836 $ (IC à 95 % : −28 608 $ à 144 280 $). À 1 an, les patients fragiles avaient moins de QALY réalisées que les patients non fragiles (0,71 [0,57 à 0,77] contre 0,82 [0,75 à 0,86]; p < 0,001), alors que le nombre de QALY gagnées était similaire (0,02 [−0,02 à 0,05] contre 0,02 [0,00 à 0,04]; p = 0,58; différence médiane : 0,003 [IC à 95 % : −0,01 à 0,02]) chez les patients fragiles et non fragiles. CONCLUSIONS: Le dépistage de la fragilité a permis de repérer une population associée à une perte plus importante de qualité de vie et à des coûts plus élevés en soins de santé. Les coûts attribuables à la fragilité représentent des coûts de renonciation qui doivent être considérés dans la planification future des services de chirurgie cardiaque, dans le contexte du vieillissement de notre population et de la prévalence croissante de fragilité.

Early mortality in critical illness - A descriptive analysis of patients who died within 24 hours of ICU admission.

PURPOSE: To describe patients who die within 24 h of ICU admission in order to better optimize care delivery. METHODS: This was a retrospective cohort study of patients ≥18 years old admitted to 17 adult ICUs in Alberta, Canada from January 1, 2016 and June 30, 2017. Data were obtained from a provincial clinical information system and data repository. The primary outcome was incidence of ICU death within 24 h of admission. Secondary outcomes were patient and system factors associated with early death. Variables of interest were identified a priori and examined using multivariable logistic regression. RESULTS: Of 19,556 patients admitted to ICU in an 18-month period, 3.3% died within 24 h, representing 29.8% of ICU deaths. Factors associated with early death were age (adjusted-OR 0.99, 95% CI, 0.9-1.0), acuity (adjusted-OR 1.3, 95% CI, 1.3-1.4), admission from the Emergency Department (ED; adjusted-OR 1.5, 95% CI, 1.1-1.9) and surgical (adjusted-OR 2.27, 95% CI, 1.4-3.6), neurologic (adjusted-OR 4.6, 95% CI, 3.1-6.9) or trauma diagnosis (adjusted-OR 6.1, 95% CI, 2.4-15.6). CONCLUSION: Patients who die within 24 h constitute one third of ICU deaths. Age, acuity, admission from the ED and surgical, neurologic or trauma-related admission diagnosis correlate with early death.

Subcellular resolution three-dimensional light-field imaging with genetically encoded voltage indicators.

Significance: Light-field microscopy (LFM) enables high signal-to-noise ratio (SNR) and light efficient volume imaging at fast frame rates. Voltage imaging with genetically encoded voltage indicators (GEVIs) stands to particularly benefit from LFM's volumetric imaging capability due to high required sampling rates and limited probe brightness and functional sensitivity. Aim: We demonstrate subcellular resolution GEVI light-field imaging in acute mouse brain slices resolving dendritic voltage signals in three spatial dimensions. Approach: We imaged action potential-induced fluorescence transients in mouse brain slices sparsely expressing the GEVI VSFP-Butterfly 1.2 in wide-field microscopy (WFM) and LFM modes. We compared functional signal SNR and localization between different LFM reconstruction approaches and between LFM and WFM. Results: LFM enabled three-dimensional (3-D) localization of action potential-induced fluorescence transients in neuronal somata and dendrites. Nonregularized deconvolution decreased SNR with increased iteration number compared to synthetic refocusing but increased axial and lateral signal localization. SNR was unaffected for LFM compared to WFM. Conclusions: LFM enables 3-D localization of fluorescence transients, therefore eliminating the need for structures to lie in a single focal plane. These results demonstrate LFM's potential for studying dendritic integration and action potential propagation in three spatial dimensions.

3D Localization for Light-Field Microscopy via Convolutional Sparse Coding on Epipolar Images.

Light-field microscopy (LFM) is a type of all-optical imaging system that is able to capture 4D geometric information of light rays and can reconstruct a 3D model from a single snapshot. In this paper, we propose a new 3D localization approach to effectively detect 3D positions of neuronal cells from a single light-field image with high accuracy and outstanding robustness to light scattering. This is achieved by constructing a depth-aware dictionary and by combining it with convolutional sparse coding. Specifically, our approach includes 3 key parts: light-field calibration, depth-aware dictionary construction, and localization based on convolutional sparse coding (CSC). In the first part, an observed raw light-field image is calibrated and then decoded into a two-plane parameterized 4D format which leads to the epi-polar plane image (EPI). The second part involves simulating a set of light-fields using a wave-optics forward model for a ball-shaped volume that is located at different depths. Then, a depth-aware dictionary is constructed where each element is a synthetic EPI associated to a specific depth. Finally, by taking full advantage of the sparsity prior and shift-invariance property of EPI, 3D localization is achieved via convolutional sparse coding on an observed EPI with respect to the depth-aware EPI dictionary. We evaluate our approach on both non-scattering specimen (fluorescent beads suspended in agarose gel) and scattering media (brain tissues of genetically encoded mice). Extensive experiments demonstrate that our approach can reliably detect the 3D positions of granular targets with small Root Mean Square Error (RMSE), high robustness to optical aberration and light scattering in mammalian brain tissues.

Dedicated Setup for the Photoconversion of Fluorescent Dyes for Functional Electron Microscopy.

Here, we describe a cost-effective setup for targeted photoconversion of fluorescent signals into electron dense ones. This approach has offered invaluable insights in the morphology and function of fine neuronal structures. The technique relies on the localized oxidation of diaminobenzidine (DAB) mediated by excited fluorophores. This paper includes a detailed description of how to build a simple photoconversion setup that can increase reliability and throughput of this well-established technique. The system described here, is particularly well-suited for thick neuronal tissue, where light penetration and oxygen diffusion may be limiting DAB oxidation. To demonstrate the system, we use Correlative Light and Electron Microscopy (CLEM) to visualize functionally-labeled individual synaptic vesicles released onto an identified layer 5 neuron in an acute cortical slice. The setup significantly simplifies the photoconversion workflow, increasing the depth of photoillumination, improving the targeting of the region of interest and reducing the time required to process each individual sample. We have tested this setup extensively for the photoconversion of FM 1-43FX and Lucifer Yellow both excited at 473 nm. In principle, the system can be adapted to any dye or nanoparticle able to oxidize DAB when excited by a specific wavelength of light.

All-optical crosstalk-free manipulation and readout of Chronos-expressing neurons.

All optical neurophysiology allows manipulation and readout of neural network activity with single-cell spatial resolution and millisecond temporal resolution. Neurons can be made to express proteins that actuate transmembrane currents upon light absorption, enabling optical control of membrane potential and action potential signalling. In addition, neurons can be genetically or synthetically labelled with fluorescent reporters of changes in intracellular calcium concentration or membrane potential. Thus, to optically manipulate and readout neural activity in parallel, two spectra are involved: the action spectrum of the actuator, and the absorption spectrum of the fluorescent reporter. Due to overlap in these spectra, previous all-optical neurophysiology paradigms have been hindered by spurious activation of neuronal activity caused by the readout light. Here, we pair the blue-green absorbing optogenetic actuator, Chronos, with a deep red-emitting fluorescent calcium reporter CaSiR-1. We show that cultured Chinese hamster ovary cells transfected with Chronos do not exhibit transmembrane currents when illuminated with wavelengths and intensities suitable for exciting one-photon CaSiR-1 fluorescence. We then demonstrate crosstalk-free, high signal-to-noise ratio CaSiR-1 red fluorescence imaging at 100 frames s-1 of Chronos-mediated calcium transients evoked in neurons with blue light pulses at rates up to 20 Hz. These results indicate that the spectral separation between red light excited fluorophores, excited efficiently at or above 640 nm, with blue-green absorbing opsins such as Chronos, is sufficient to avoid spurious opsin actuation by the imaging wavelengths and therefore enable crosstalk-free all-optical neuronal manipulation and readout.

Implementation of population-level screening for frailty among patients admitted to adult intensive care in Alberta, Canada.

PURPOSE: A substantial proportion of patients admitted to intensive care units (ICUs) are frail; however, the epidemiology of frailty has not been explored at a population-level. Following implementation of a validated frailty measure into a provincial ICU clinical information system, we describe the population-based prevalence and outcomes of frailty in patients admitted to ICUs. METHODS: Retrospective cohort study of adult admissions to 17 ICUs. Data were captured using eCritical Alberta. A Clinical Frailty Scale (CFS) score assigned at ICU admission was used to define the exposure (CFS score ≥ 5). Primary outcome was hospital mortality. Secondary outcomes were ICU and hospital stay, and receipt of organ support. RESULTS: Fifteen thousand two hundred and thirty-eight patients (81%) were assigned a CFS score at ICU admission. Of these, 28% (95% confidence interval [CI], 27 to 28) were frail. Prevalence of frailty was 9-43% across ICUs. Frail patients were older [mean (standard deviation) 63 (15) vs 56 (17) yr; P < 0.001], more likely to be male (54% vs 46% female; P < 0.001), and had higher APACHE II scores [22 (8) vs 17 (8); P < 0.001] compared with non-frail patients. Frail patients received less mechanical ventilation (62% vs 68%; P < 0.001) and vasoactive therapy (24% vs 57%; P < 0.001), but more non-invasive ventilation (22% vs 9%; P < 0.001). Frail patients had higher hospital mortality (23% vs 9%; adjusted odds ratio, 1.80; 95% CI, 1.64 to 2.05, along with longer ICU stay (median [interquartile range] 4 [2-8] vs 3 [2-6] days; P < 0.001), and longer hospital stay (16 [8-36] vs 10 [5-20] days; P < 0.001) compared with non-frail patients. CONCLUSION: A validated measure of frailty can be implemented at the population level in ICU. Frailty is common in ICU patients and has implications for health service use and clinical outcomes.

Corrigendum: Single-Neuron Level One-Photon Voltage Imaging With Sparsely Targeted Genetically Encoded Voltage Indicators.

[This corrects the article DOI: 10.3389/fncel.2019.00039.].