Introduction to the Optics and the Brain 2023 feature issue.

A feature issue is being presented by a team of guest editors containing papers based on contributed submissions including studies presented at Optics and the Brain, held April 24-27, 2023 as part of Optica Biophotonics Congress: Optics in the Life Sciences, in Vancouver, Canada.

One size doesn't fit all: methodological reflections in conducting community-based behavioural science research to tailor COVID-19 vaccination initiatives for public health priority populations.

BACKGROUND: Promoting the uptake of vaccination for infectious diseases such as COVID-19 remains a global challenge, necessitating collaborative efforts between public health units (PHUs) and communities. Applied behavioural science can play a crucial role in supporting PHUs' response by providing insights into human behaviour and informing tailored strategies to enhance vaccination uptake. Community engagement can help broaden the reach of behavioural science research by involving a more diverse range of populations and ensuring that strategies better represent the needs of specific communities. We developed and applied an approach to conducting community-based behavioural science research with ethnically and socioeconomically diverse populations to guide PHUs in tailoring their strategies to promote COVID-19 vaccination. This paper presents the community engagement methodology and the lessons learned in applying the methodology. METHODS: The community engagement methodology was developed based on integrated knowledge translation (iKT) and community-based participatory research (CBPR) principles. The study involved collaboration with PHUs and local communities in Ontario, Canada to identify priority groups for COVID-19 vaccination, understand factors influencing vaccine uptake and co-design strategies tailored to each community to promote vaccination. Community engagement was conducted across three large urban regions with individuals from Eastern European communities, African, Black, and Caribbean communities and low socioeconomic neighbourhoods. RESULTS: We developed and applied a seven-step methodology for conducting community-based behavioural science research: (1) aligning goals with system-level partners; (2) engaging with PHUs to understand priorities; (3) understanding community strengths and dynamics; (4) building relationships with each community; (5) establishing partnerships (community advisory groups); (6) involving community members in the research process; and (7) feeding back and interpreting research findings. Research partnerships were successfully established with members of prioritized communities, enabling recruitment of participants for theory-informed behavioural science interviews, interpretation of findings, and co-design of targeted recommendations for each PHU to improve COVID-19 vaccination uptake. Lessons learned include the importance of cultural sensitivity and awareness of sociopolitical context in tailoring community engagement, being agile to address the diverse and evolving priorities of PHUs, and building trust to achieve effective community engagement. CONCLUSION: Effective community engagement in behavioural science research can lead to more inclusive and representative research. The community engagement approach developed and applied in this study acknowledges the diversity of communities, recognizes the central role of PHUs, and can help in addressing complex public health challenges.

Long-term in vivo three-photon imaging reveals region-specific differences in healthy and regenerative oligodendrogenesis.

The generation of new myelin-forming oligodendrocytes in the adult central nervous system is critical for cognitive function and regeneration following injury. Oligodendrogenesis varies between gray and white matter regions, suggesting that local cues drive regional differences in myelination and the capacity for regeneration. However, the layer- and region-specific regulation of oligodendrocyte populations is unclear due to the inability to monitor deep brain structures in vivo. Here we harnessed the superior imaging depth of three-photon microscopy to permit long-term, longitudinal in vivo three-photon imaging of the entire cortical column and subcortical white matter in adult mice. We find that cortical oligodendrocyte populations expand at a higher rate in the adult brain than those of the white matter. Following demyelination, oligodendrocyte replacement is enhanced in the white matter, while the deep cortical layers show deficits in regenerative oligodendrogenesis and the restoration of transcriptional heterogeneity. Together, our findings demonstrate that regional microenvironments regulate oligodendrocyte population dynamics and heterogeneity in the healthy and diseased brain.

Hayling and stroop tests tap dissociable deficits and network-level neural correlates.

Although many executive function screens have been developed, it is not yet clear whether these assessments are equally effective in detecting post-stroke deficits of initiation and inhibition. This study presents a comparative analysis of the Stroop and Hayling tests aiming to evaluate whether these tests measure the same underlying cognitive functions and to identify the neural correlates of the deficits detected by both tasks. Sixty six stroke survivors and 70 healthy ageing controls completed the Hayling and Stroop tests. Stroke patients were found to exhibit qualitative performance differences across analogous Stroop and Hayling Test metrics intended to tap initiation and inhibition. The Stroop test was found to have high specificity to abnormal performance, but low sensitivity relative to the Hayling Test. Minimal overlap was present between the network-level correlates of analogous Stroop and Hayling Test metrics. Hayling Task strategy use metrics were significantly associated with distinct patterns of disconnection in stroke survivors, providing novel insight into the neural correlates of fine-grained behavioural patterns. Overall, these findings strongly suggest that the functions tapped by the Stroop and Hayling Test are both behaviourally and anatomically dissociable. The Hayling Test was found to offer improved sensitivity and detail relative to the Stroop test. This novel demonstration of the Hayling Test within the stroke population suggests that this task represents an effective measure for quantifying post-stroke initiation and inhibition deficits.

Sequential activity of CA1 hippocampal cells constitutes a temporal memory map for associative learning in mice.

Sequential neural dynamics encoded by time cells play a crucial role in hippocampal function. However, the role of hippocampal sequential neural dynamics in associative learning is an open question. We used two-photon Ca2+ imaging of dorsal CA1 (dCA1) neurons in the stratum pyramidale (SP) in head-fixed mice performing a go-no go associative learning task to investigate how odor valence is temporally encoded in this area of the brain. We found that SP cells responded differentially to the rewarded or unrewarded odor. The stimuli were decoded accurately from the activity of the neuronal ensemble, and accuracy increased substantially as the animal learned to differentiate the stimuli. Decoding the stimulus from individual SP cells responding differentially revealed that decision-making took place at discrete times after stimulus presentation. Lick prediction decoded from the ensemble activity of cells in dCA1 correlated linearly with lick behavior. Our findings indicate that sequential activity of SP cells in dCA1 constitutes a temporal memory map used for decision-making in associative learning. VIDEO ABSTRACT.

Deep learning and CRISPR-Cas13d ortholog discovery for optimized RNA targeting.

Effective and precise mammalian transcriptome engineering technologies are needed to accelerate biological discovery and RNA therapeutics. Despite the promise of programmable CRISPR-Cas13 ribonucleases, their utility has been hampered by an incomplete understanding of guide RNA design rules and cellular toxicity resulting from off-target or collateral RNA cleavage. Here, we quantified the performance of over 127,000 RfxCas13d (CasRx) guide RNAs and systematically evaluated seven machine learning models to build a guide efficiency prediction algorithm orthogonally validated across multiple human cell types. Deep learning model interpretation revealed preferred sequence motifs and secondary features for highly efficient guides. We next identified and screened 46 novel Cas13d orthologs, finding that DjCas13d achieves low cellular toxicity and high specificity-even when targeting abundant transcripts in sensitive cell types, including stem cells and neurons. Our Cas13d guide efficiency model was successfully generalized to DjCas13d, illustrating the power of combining machine learning with ortholog discovery to advance RNA targeting in human cells.

Barriers and enablers to and strategies for promoting domestic plasma donation throughout the world: Overarching protocol for three systematic reviews.

INTRODUCTION: The growing demand for plasma protein products has caused concern in many countries who largely rely on importing plasma products produced from plasma collected in the United States and Europe. Optimizing recruitment and retention of a diversity of plasma donors is therefore important for supporting national donation systems that can reliably meet the most critical needs of health services. This series of three systematic reviews aims to synthesize the known barriers and enablers to source plasma donation from the qualitative and survey-based literature and identify which strategies that have shown to be effective in promoting increased intention to, and actual donation of, source plasma. METHODS AND ANALYSIS: Primary studies involving source or convalescent plasma donation via plasmapheresis will be included. The search strategy will capture all potentially relevant studies to each of the three reviews, creating a database of plasma donation literature. Study designs will be subsequently identified in the screening process to facilitate analysis according to the unique inclusion criteria of each review (i.e., qualitative, survey, and experimental designs). The search will be conducted in the electronic databases SCOPUS, MEDLINE, EMBASE, PsycINFO, and CINAHL without date or language restrictions. Studies will be screened, and data will be extracted, in duplicate by two independent reviewers with disagreements resolved through consensus. Reviews 1 and 2 will draw on the Theoretical Domains Framework and Intersectionality, while Review 3 will be informed by Behaviour Change Intervention Ontologies. Directed content analysis and framework analysis (Review 1), and descriptive and inferential syntheses (Reviews 2 and 3), will be used, including meta-analyses if appropriate. DISCUSSION: This series of related reviews will serve to provide a foundation of what is known from the published literature about barriers and enablers to, and strategies for promoting, plasma donation worldwide.

Long-term in vivo three-photon imaging reveals region-specific differences in healthy and regenerative oligodendrogenesis.

The generation of new myelin-forming oligodendrocytes in the adult CNS is critical for cognitive function and regeneration following injury. Oligodendrogenesis varies between gray and white matter regions suggesting that local cues drive regional differences in myelination and the capacity for regeneration. Yet, the determination of regional variability in oligodendrocyte cell behavior is limited by the inability to monitor the dynamics of oligodendrocytes and their transcriptional subpopulations in white matter of the living brain. Here, we harnessed the superior imaging depth of three-photon microscopy to permit long-term, longitudinal in vivo three-photon imaging of an entire cortical column and underlying subcortical white matter without cellular damage or reactivity. Using this approach, we found that the white matter generated substantially more new oligodendrocytes per volume compared to the gray matter, yet the rate of population growth was proportionally higher in the gray matter. Following demyelination, the white matter had an enhanced population growth that resulted in higher oligodendrocyte replacement compared to the gray matter. Finally, deep cortical layers had pronounced deficits in regenerative oligodendrogenesis and restoration of the MOL5/6-positive oligodendrocyte subpopulation following demyelinating injury. Together, our findings demonstrate that regional microenvironments regulate oligodendrocyte population dynamics and heterogeneity in the healthy and diseased brain.

Two-photon microendoscope for label-free imaging in stereotactic neurosurgery.

We demonstrate a gradient refractive index (GRIN) microendoscope with an outer diameter of ∼1.2 mm and a length of ∼186 mm that can fit into a stereotactic surgical cannula. Two photon imaging at an excitation wavelength of 900 nm showed a field of view of ∼180 microns and a lateral and axial resolution of 0.86 microns and 9.6 microns respectively. The microendoscope was tested by imaging autofluorescence and second harmonic generation (SHG) in label-free human brain tissue. Furthermore, preliminary image analysis indicates that image classification models can predict if an image is from the subthalamic nucleus or the surrounding tissue using conventional, bench-top two-photon autofluorescence.

MicroLED light source for optical sectioning structured illumination microscopy.

Optical sectioning structured illumination microscopy (OS-SIM) provides optical sectioning capability in wide-field microscopy. The required illumination patterns have traditionally been generated using spatial light modulators (SLM), laser interference patterns, or digital micromirror devices (DMDs) which are too complex to implement in miniscope systems. MicroLEDs have emerged as an alternative light source for patterned illumination due to their extreme brightness capability and small emitter sizes. This paper presents a directly addressable striped microLED microdisplay with 100 rows on a flexible cable (70 cm long) for use as an OS-SIM light source in a benchtop setup. The overall design of the microdisplay is described in detail with luminance-current-voltage characterization. OS-SIM implementation with a benchtop setup shows the optical sectioning capability of the system by imaging within a 500 µm thick fixed brain slice from a transgenic mouse where oligodendrocytes are labeled with a green fluorescent protein (GFP). Results show improved contrast in reconstructed optically sectioned images of 86.92% (OS-SIM) compared with 44.31% (pseudo-widefield). MicroLED based OS-SIM therefore offers a new capability for deep tissue widefield imaging.

Leveraging community health workers as vaccinators: a case study exploring the role of Malawi's Health Surveillance Assistants in delivering routine immunization services.

BACKGROUND: Global chronic health worker shortages and stagnating routine immunization rates require new strategies to increase vaccination coverage and equity. As trained, trusted members of their local communities, community health workers (CHWs) are in a prime position to expand the immunization workforce and increase vaccination coverage in under-reached communities. Malawi is one of only a few countries that relies on CHWs-called Health Surveillance Assistants (HSAs) in Malawi-to administer routine immunizations, and as such offers a unique example of how this can be done. CASE PRESENTATION: We sought to describe the operational and programmatic characteristics of a functional CHW-led routine immunization program by conducting interviews with HSAs, HSA supervisors, ministry of health officials, and community members in Malawi. This case study describes how and where HSAs provide vaccinations, their vaccination-related responsibilities, training and supervision processes, vaccine safety considerations, and the community-level vaccine supply chain. Interview participants consistently described HSAs as a high-functioning vaccination cadre, skilled and dedicated to increasing vaccine access for children. They also noted a need to strengthen some aspects of professional support for HSAs, particularly related to training, supervision, and supply chain processes. Interviewees agreed that other countries should consider following Malawi's example and use CHWs to administer vaccines, provided they can be sufficiently trained and supported. CONCLUSIONS: This account from Malawi provides an example of how a CHW-led vaccination program operates. Leveraging CHWs as vaccinators is a promising yet under-explored task-shifting approach that shows potential to help countries maximize their health workforce, increase vaccination coverage and reach more zero-dose children. However, more research is needed to produce evidence on the impact of leveraging CHWs as vaccinators on patient safety, immunization coverage/vaccine equity, and cost-effectiveness as compared to use of other cadres for routine immunization.

Navigating imperfect policies to donate plasma: Survey on plasma donation and a pilot plasma donation program among men who have sex with men in Canada.

BACKGROUND: In 2021, Canada implemented a pilot plasma program allowing some sexually active men who have sex with men (including but not limited to gay and bisexual men; gbMSM) to donate plasma. Changes to plasma donation policy could help address inequities in access to plasma donation and increase Canada's domestically collected plasma supply if more gbMSM donate as a result. We aimed to (1) examine views regarding plasma donation and the pilot program prior to implementation and (2) identify modifiable theory-informed predictors of gbMSM's intention to donate plasma. METHODS: We developed, piloted, and disseminated a questionnaire informed by the Theoretical Domains Framework (TDF). We recruited gbMSM in London (ON) and Calgary (AB) to an anonymous, online cross-sectional survey. RESULTS: A total of 246 gbMSM completed the survey. On scales from 1 (strongly disagree) to 5 (strongly agree), general intention to donate was high (mean = 4.24; SD = 0.94). The pilot program itself was mostly acceptable (mean = 3.71, SD = 1.16), but the intention to donate under the unique requirements of the pilot program was lower than general intention (mean = 3.58; SD = 1.26). Two domains from the theoretical domains framework (TDF) (beliefs about consequences of donating plasma and social influences) were independently associated with general intention to donate. DISCUSSION: The pilot plasma program as an incremental step toward more inclusive policies was mostly viewed as acceptable by the impacted communities. Historical and ongoing exclusions create unique barriers to donation. There are clear opportunities for developing theory-informed interventions to support gbMSM to donate plasma as policies continue to become more inclusive and more become eligible to donate.

Improved access yet inequitable experience: gay, bisexual and other men who have sex with men's views of more inclusive criteria for source plasma donation.

BACKGROUND: Canada has incrementally reduced restrictions to blood and plasma donation that impact men who have sex with men, gay, bisexual, and queer men, and some Two Spirit, transgender and non-binary individuals (MSM/2SGBTQ+). Prior to the launch of a pilot program in 2021 enabling some MSM/2SGBTQ + to donate source plasma, we explored the acceptability of the program among individuals who could become eligible to donate in the program. METHODS: We invited men identifying as MSM/2SGBTQ + to participate in two consecutive semi-structured interviews to explore their views on blood and plasma donation policy, plasma donation, and the proposed Canadian plasma donation program. Interview transcripts were analyzed thematically and acceptability-related themes were mapped onto the Theoretical Framework of Acceptability. RESULTS: Twenty-seven men identifying as having sex with men participated in 53 interviews. Eighteen themes were mapped onto the seven construct domains of the Theoretical Framework of Acceptability. Underlying all aspects of acceptability was a tension between four primary values influencing participants' views: altruism, equity, supply sufficiency, and evidence-based policy. The program was viewed as welcome progress on a discriminatory policy, with many excited to participate, yet tension with inequitable aspects of the program undermined support for the program and interest to contribute to it. The high demands of the program are unique for MSM/2SGBTQ + and are only tolerable as part of a program that is an incremental and instrumental step to more equitable donation policies. CONCLUSION: Findings highlight past experiences of exclusion in Canada as a unique and critical part of the context of the donation experience among MSM/2SGBTQ+. Despite the program's goals of greater inclusivity of MSM/2SGBTQ + individuals, the anticipated experience of the program included continued stigmatization and inequities. Future research should seek to understand the experienced views of MSM/2SGBTQ + donors to ensure that as policies change, policies are implemented equitably.

Electronic Assistive Technology to Support Memory Function After Traumatic Brain Injury: A Systematic Review of Efficacy and User Perspectives.

Abstract Rapid technology advances have led to diverse assistive technology (AT) options for use in memory rehabilitation after traumatic brain injury (TBI). This systematic review aimed to evaluate the efficacy of electronic AT for supporting phases of memory in daily life after TBI. A secondary aim was to examine user perspectives on the utility of AT and factors influencing uptake or use. A systematic search of PsycINFO, MEDLINE, Cumulative Index of Nursing and Allied Health Literature (CINAHL), Excerpta Medica database (Embase), Scopus, and Cochrane Library was conducted from database inception to June 13, 2022, to identify eligible studies. Methodological quality was assessed by two independent reviewers. Nineteen eligible articles involving a total of 311 participants included four randomized controlled trials (RCTs; Class I), five single-case experimental designs (Class II), and 10 pre-post group (n > 10) or single-case studies without experimental control (Class III). Three Class I studies, two Class II studies and eight Class III studies supported the efficacy of AT for supporting memory functioning. Treatment fidelity was not examined in any study. There was the most empirical support for the efficacy of AT for facilitating retrieval and execution phases of memory (i.e., supported by 6/9 studies) with external support to encode memory intentions or pre-programmed reminders. Further controlled studies are needed to determine whether outcomes vary according to individuals' level of independence with use (e.g., self-initiated vs. pre-programmed reminders) and to examine user characteristics and design features influencing uptake and effectiveness. Greater involvement of end-users with brain injury in the design and evaluation of AT features is also recommended to enhance usability and uptake in daily life.

Community Health Workers as Vaccinators: A Rapid Review of the Global Landscape, 2000-2021.

INTRODUCTION: Community health workers (CHWs) could expand immunization access in under-reached communities by administering vaccines. This rapid review identifies countries where CHWs administered vaccines and synthesizes health systems factors that may contribute to or detract from the feasibility of CHWs administering vaccines. METHODS: We conducted a rapid review of peer-reviewed literature from 3 databases and gray literature identified through web searches and by CHW subject matter experts. We treated extracted data on conditions related to vaccine administration by CHWs as qualitative data and conducted deductive content analysis. RESULTS: We retained 32 documents from 497 initial records and identified 23 CHW cadres that vaccinated in 20 countries, ranging from long-established national programs delivering routine immunizations to pilot projects delivering 1 specific vaccine. CHWs who vaccinate face the following challenges: (1) inadequate supply chain training, (2) inadequate cold chain equipment, (3) transportation for supplies and to communities, (4) heavy existing workload, (5) inadequate or irregular remuneration, (6) inadequate or irregular supervision. CONCLUSION: To improve immunization coverage in underimmunized and zero-dose communities, countries where CHWs vaccinate should provide CHWs with adequate remuneration, supervision, supply chain support and management, and formal integration within the health system. CHWs administered vaccines in 20 of the 75 countries with documented CHW programs, suggesting the majority of an estimated 3.3 million CHWs globally do not yet administer vaccines. In light of health care workforce shortages and immunization equity gaps, further exacerbated by the COVID-19 pandemic, policymakers should consider task-shifting vaccine administration to CHWs to bolster immunization access for under-reached communities. Additional systematic documentation is needed to further explore best practices to support CHWs as vaccinators, especially related to supply chain, policy, safety, and efficacy.

"I Pulled Them Apart and Told Them to Stop": A Mixed-Methods Examination of Bystander Behavior, Preparedness, and Emotional Reaction.

The goals of this mixed-methods study were to examine self-reported behavior of bystanders who intervened in specific situations of potential sexual violence and physical dating violence, to explore their sense of preparedness to intervene, and to assess bystanders' emotional reactions to their self-reported action or inaction when witnessing potential sexual and dating violence. The participants (n = 553, 65.2% female, 76% freshmen, M age = 18.7 years), responded to a sequence of questions pertaining to witnessing and intervening in specific potentially dangerous situations, emotional reactions to their action or inaction, and preparedness. Bystander participants also provided narrative responses describing their behavior. We used joint display analyses to integrate, analyze, and interpret the qualitative and quantitative data. Of the 553 participants, 38% witnessed "a man talking to a woman and she looked uncomfortable," 27% witnessed "someone taking an intoxicated person up to their room," and 39% witnessed "someone grabbing or pushing their boyfriend or girlfriend"; of those who witnessed, the percentage of those who intervened was 42%, 25%, and 19%, respectively. Bystander behavior involved one of 5Ds: distract, direct, delegate, distance, diffuse, or a combination. Although most bystanders did not get involved, most (94.6%) reported that they felt prepared to intervene. For those who intervened, most reported feeling positive about their action; however, most who did not intervene reported feeling negative about their inaction. Implications for college bystanders and bystander education programs are discussed.

GRINtrode: a neural implant for simultaneous two-photon imaging and extracellular electrophysiology in freely moving animals.

Significance: In vivo imaging and electrophysiology are powerful tools to explore neuronal function that each offer unique complementary information with advantages and limitations. Capturing both data types from the same neural population in the freely moving animal would allow researchers to take advantage of the capabilities of both modalities and further understand how they relate to each other. Aim: Here, we present a head-mounted neural implant suitable for in vivo two-photon imaging of neuronal activity with simultaneous extracellular electrical recording in head-fixed or fiber-coupled freely moving animals. Approach: A gradient refractive index (GRIN) lens-based head-mounted neural implant with extracellular electrical recording provided by tetrodes on the periphery of the GRIN lens was chronically implanted. The design of the neural implant allows for recording from head-fixed animals, as well as freely moving animals by coupling the imaging system to a coherent imaging fiber bundle. Results: We demonstrate simultaneous two-photon imaging of GCaMP and extracellular electrophysiology of neural activity in awake head-fixed and freely moving mice. Using the collected information, we perform correlation analysis to reveal positive correlation between optical and local field potential recordings. Conclusion: Simultaneously recording neural activity using both optical and electrical methods provides complementary information from each modality. Designs that can provide such bi-modal recording in freely moving animals allow for the investigation of neural activity underlying a broader range of behavioral paradigms.

Fluoride Content of Ready-to-Eat Infant Foods and Drinks in Australia.

The use of fluoride is effective in preventing dental caries. However, an excessive intake of fluoride leads to dental fluorosis, making it necessary to regularly monitor the fluoride intake especially for infants. There is hitherto a lack of information on fluoride content in infant foods from an Australian perspective. Therefore, this study aims to estimate the amount of fluoride content from a range of commercially available ready-to-eat (RTE) infant foods and drinks available in Australia. Based on an external calibration method, potentiometry involving a fluoride ion selective electrode and a silver|silver chloride reference electrode was conducted to analyse the fluoride content of a total of 326 solid food samples and 49 liquid food samples in this work. Our results showed an overall median (range) fluoride content of 0.16 (0.001-2.8) µg F/g of solid food samples, and 0.020 (0.002-1.2) µg F/mL of liquid food samples. In addition, ~77.5% of the liquid samples revealed a fluoride content < 0.05% µg F/mL. The highest variation of fluoride concentration (0.014-0.92 µg F/g) was found in formulas for ≥6 month-old infants. We have attributed the wide fluoride content variations in ready-to-eat infant foods and drinks to the processing steps, different ingredients and their origins, including water. In general, we found the fluoride content in most of the collected samples from Australian markets to be high and may therefore carry a risk of dental fluorosis. These results highlight the need for parents to receive appropriate information on the fluoride content of ready-to-eat infant food and drinks.

Staff perspectives on barriers and enablers to implementing alternative source plasma eligibility criteria for gay, bisexual, and other men who have sex with men.

BACKGROUND: Canadian Blood Services introduced new eligibility criteria that allows some sexually active gay, bisexual, and other men who have sex with men (gbMSM) to donate source plasma, marking a significant change from time-based deferral criteria. We aimed to identify potential barriers and enablers to implementing the new criteria from the perspective of donor center staff. STUDY DESIGN AND METHODS: We conducted Theoretical Domains Framework-informed interviews with staff from two source plasma donation centers in Canada. RESULTS: We completed 28 interviews between June 2020 and April 2021. Three themes representing eight domains captured key tensions. Valuing inclusive eligibility criteria: staff support inclusive criteria; many were concerned the new criteria remained discriminatory. Investing in positive donor experiences: staff wished to foster positive donor experiences; however, they worried gbMSM donors would express anger and disappointment regarding the new criteria, staff would experience unease over using stigmatizing criteria and convey nonverbal cues of discomfort, and recurring plasma donors may behave inappropriately. Supporting education, training, and transparency of eligibility criteria: participants believed providing in-person training (i.e., to explain criteria rationale, address discomfort, practice responding to donor questions) and ensuring donors and the public were well-informed of the upcoming changes would improve implementation. DISCUSSION: Participant views emphasize the importance of supporting staff through training and transparent communication to optimize the delivery of world-class equitable care for a new cohort of donors who have previously been excluded from plasma donation. Findings inform which staff supports to consider to improve implementation as policies continue to shift internationally.

Miniature structured illumination microscope for in vivo 3D imaging of brain structures with optical sectioning.

We present a high-resolution miniature, light-weight fluorescence microscope with electrowetting lens and onboard CMOS for high resolution volumetric imaging and structured illumination for rejection of out-of-focus and scattered light. The miniature microscope (SIMscope3D) delivers structured light using a coherent fiber bundle to obtain optical sectioning with an axial resolution of 18 µm. Volumetric imaging of eGFP labeled cells in fixed mouse brain tissue at depths up to 260 µm is demonstrated. The functionality of SIMscope3D to provide background free 3D imaging is shown by recording time series of microglia dynamics in awake mice at depths up to 120 µm in the brain.