3D imaging of optically cleared tissue using a simplified CLARITY method and on-chip microscopy.

In many regions globally, including low-resource settings, there is a growing trend towards using mHealth technology, such as wearable sensors, to enhance health behaviors and outcomes. However, adoption of such devices in research conducted in low-resource settings lags behind use in high-resource areas. Moreover, there is a scarcity of research that specifically examines the user experience, readiness for and challenges of integrating wearable sensors into health research and community interventions in low-resource settings specifically. This study summarizes the reactions and experiences of young women (N = 57), ages 18 to 24 years, living in poverty in Kampala, Uganda, who wore Garmin vívoactive 3 smartwatches for five days for a research project. Data collected from the Garmins included participant location, sleep, and heart rate. Through six focus group discussions, we gathered insights about the participants’ experiences and perceptions of the wearable devices. Overall, the wearable devices were met with great interest and enthusiasm by participants. The findings were organized across 10 domains to highlight reactions and experiences pertaining to device settings, challenges encountered with the device, reports of discomfort/comfort, satisfaction, changes in daily activities, changes to sleep, speculative device usage, community reactions, community dynamics and curiosity, and general device comfort. The study sheds light on the introduction of new technology in a low-resource setting and also on the complex interplay between technology and culture in Kampala’s slums. We also learned some insights into how wearable devices and perceptions may influence behaviors and social dynamics. These practical insights are shared to benefit future research and applications by health practitioners and clinicians to advance and enhance the implementation and effectiveness of wearable devices in similar contexts and populations. These insights and user experiences, if incorporated, may enhance device acceptance and data quality for those conducting research in similar settings or seeking to address population-specific needs and health issues.

This paper presents the Pixel Super Resolution with Axial Scanning (PSR-AS) technique to enhance the resolution of Lensless Digital In-line Holographic Microscopy (LDHM). By utilizing multiple holograms captured at different axial distances, PSR allows for the recovery of high-resolution information, improving the image clarity and information content. Experimental results demonstrate a twofold lateral resolution enhancement, achieving the resolution of 1.23 μm in amplitude imaging and significantly augmenting phase reconstruction quality. The integration of PSR-AS into LDHM systems leads to notable reductions in noise and artifacts, offering a promising approach for high-resolution imaging in applications such as biomedical diagnostics and environmental monitoring. Full Text: PDF References Y. Park, C. Depeursinge, and G. Popescu, "Quantitative phase imaging in biomedicine," Nature Photon, 12(10), 578 (2018). CrossRef D. Gabor, "A New Microscopic Principle," Nature, 161(4098), 777 (1948). CrossRef K. Matsushima and T. Shimobaba, "Band-Limited Angular Spectrum Method for Numerical Simulation of Free-Space Propagation in Far and Near Fields," Opt. Express, 17(22), 19662 (2009). CrossRef Y. Wu and A. Ozcan, "Lensless digital holographic microscopy and its applications in biomedicine and environmental monitoring," Methods, 136, 4 (2018). CrossRef J. Zhang, J. Sun, Q. Chen, and C. Zuo, "Resolution Analysis in a Lens-Free On-Chip Digital Holographic Microscope," IEEE Transactions on Computational Imaging, 6, 697 (2020). CrossRef Gerchberg, R. W.. “A practical algorithm for the determination of phase from image and diffraction plane pictures.” Optik 35, 237 (1972). CrossRef H. Lee, J. Kim, J. Kim, P. Jeon, S. A. Lee, and D. Kim, "Noniterative sub-pixel shifting super-resolution lensless digital holography," Opt. Express,29(19), 29996 (2021). CrossRef A. Greenbaum and A. Ozcan, "Maskless imaging of dense samples using pixel super-resolution based multi-height lensfree on-chip microscopy," Opt. Express, 20(3), 3129 (2012). CrossRef J. Zhang, J. Sun, Q. Chen, J. Li, and C. Zuo, "Adaptive pixel-super-resolved lensfree in-line digital holography for wide-field on-chip microscopy," Sci Rep, 7(1), 11777 (2017). CrossRef L. I. Rudin, S. Osher, and E. Fatemi, "Nonlinear total variation based noise removal algorithms," Physica D: Nonlinear Phenomena, 60(1), 259 (1992). CrossRef

Accurate color imaging over a wide field-of-view is achieved by combining single-wavelength lens-free on-chip holographic microscopy with a color-calibrated low-cost mobile-phone microscope using a wavelet-based image fusion algorithm.

We report a portable lensless on-chip microscope that can achieve <1 µm resolution over a wide field-of-view of ∼ 24 mm(2) without the use of any mechanical scanning. This compact on-chip microscope weighs ∼ 95 g and is based on partially coherent digital in-line holography. Multiple fiber-optic waveguides are butt-coupled to light emitting diodes, which are controlled by a low-cost micro-controller to sequentially illuminate the sample. The resulting lensfree holograms are then captured by a digital sensor-array and are rapidly processed using a pixel super-resolution algorithm to generate much higher resolution holographic images (both phase and amplitude) of the objects. This wide-field and high-resolution on-chip microscope, being compact and light-weight, would be important for global health problems such as diagnosis of infectious diseases in remote locations. Toward this end, we validate the performance of this field-portable microscope by imaging human malaria parasites (Plasmodium falciparum) in thin blood smears. Our results constitute the first-time that a lensfree on-chip microscope has successfully imaged malaria parasites.

In this Letter, we propose a new, to the best of our knowledge, lensless on-chip holographic microscopy platform, which can acquire sub-pixel-shifting holograms through centimeter (cm)-level lateral translations. An LED light source is used to illuminate the sample, and two orthogonally tilted step-structure glass plates are inserted into the optical path. By merely displacing the glass plates under cm-level precision, a series of holograms with sub-pixel displacements can be obtained. Combined with our improved pixel super-resolution (PSR) algorithm, high-quality PSR phase imaging can be achieved. Tests on the high-resolution USAF1951 target demonstrate that the system can achieve a half-width resolution of 870 nm by a camera with a pixel size of 1.67 µm. Additionally, imaging experiments were conducted on phase-type sinusoidal gratings, yeasts, red blood cells, and lilium ovary sections, respectively. The results show that the system can achieve large field-of-view, high-resolution phase imaging under low-cost hardware conditions and holds promise for its applications in biology and medicine.

Communication and teamwork are important aspects of medicine and have been a recent focus of resuscitation. Culture can influence communication and teamwork, and these effects have not been studied in low-resource settings. Using a case study and the TEAM scale, we evaluated how culture influences teamwork and communication during resuscitation simulations, in addition to examining other challenges of simulation research in low-resource settings. We observed lower scores in leadership and communication skills than have been seen in other studies using the TEAM scale, which led us to evaluate the possible role of culture in influencing these skills. The high power distance and collectivism in Latin America can make communication difficult, especially during debriefing. Furthermore, in a male-biased medical hierarchy, female nurses may be less likely to voice concerns. Ultimately, this commentary provides advice for taking the influences of culture into account when planning future simulation training in low-resource settings.

Recruitment and follow up of study participants in surgery research in low resource settings

Obesity in pregnancy is a growing global health challenge, with increasing prevalence across high-income, low- and middle-income countries (LMICs). Maternal obesity is associated with significant risks, including gestational diabetes, hypertensive disorders, and delivery complications, as well as adverse fetal outcomes such as macrosomia, stillbirth, and neonatal metabolic dysfunction. These complications not only pose immediate threats to maternal and fetal health but also have long-term implications, influencing fetal genetic programming and perpetuating a cycle of obesity and metabolic diseases. Epigenetic mechanisms, such as DNA methylation and histone modification, play a crucial role in altering fetal gene expression, predisposing offspring to obesity, insulin resistance, and cardiometabolic disorders. The burden of maternal obesity is particularly concerning in LMICs like Nigeria, where limited healthcare resources and shifting dietary patterns exacerbate the problem. Despite advancements in understanding the mechanisms underlying fetal programming, research gaps remain, particularly regarding region-specific data and long term trans-generational effects. Effective prevention and management strategies must integrate pre-pregnancy, antenatal, and postnatal interventions, alongside public health initiatives that promote healthy nutrition, physical activity, and community engagement. Multidisciplinary approaches, incorporating evidence-based clinical practices with culturally tailored interventions, are essential in mitigating the impact of maternal obesity. Addressing this public health concern requires concerted efforts from healthcare providers, policymakers, and researchers to enhance maternal and neonatal outcomes. Strengthening healthcare systems, improving awareness, and fostering research in low resource settings will be critical to breaking the cycle of obesity and securing a healthier future for subsequent generations.

Pixel super-resolution (PSR) techniques have been developed to overcome the sampling limit in lensless digital holographic imaging. However, the inherent non-convexity of the PSR phase retrieval problem can potentially degrade reconstruction quality by causing the iterations to tend toward a false local minimum. Furthermore, the ill posedness of the up-sampling procedure renders PSR algorithms highly susceptible to noise. In this Letter, we propose a heuristic PSR algorithm with adaptive smoothing (AS-PSR) to achieve high-fidelity reconstruction. By automatically adjusting the intensity constraints on the estimated field, the algorithm can effectively locate the optimal solution and converge with high reconstruction quality, pushing the resolution toward the diffraction limit. The proposed method is verified experimentally within a coherent modulation phase retrieval framework, achieving a twofold improvement in resolution. The AS-PSR algorithm can be further applied to other phase retrieval methods based on alternating projection.

Quantitative detection of cellulose particles in transformer oil based on a lens-free holographic microscope

Operational research (OR) in eye care within resource-constrained settings helps develop context-specific solutions to local challenges. Building OR capacity among eye care personnel enables them to independently generate evidence that drives improvements in eye care delivery. This protocol describes the extended phase of the Institutional Operational Research Capacity Building (I-ORCB) program designed to train eye care professionals in the fundamentals and applications of OR. The I-ORCB program will be conducted in collaboration with Seva Canada and the Pragyaan Sustainable Health Outcomes Foundation over 3 years (2024-2027). A total of 10 partner eye hospitals in India and Nepal will participate. The training is organized around 7 work packages covering quantitative and qualitative research methods, data management and analysis, community engagement, scientific writing, grant writing, and ethics. The program will be implemented in two sequential phases: (1) protocol development and ethics committee submission and (2) mentoring, data collection, data analysis, and manuscript preparation. Delivery will include workshops, ongoing mentorship, e-resources, and structured monitoring mechanisms. Evaluation will follow the Kirkpatrick model, and cost-effectiveness will be assessed through the change in knowledge among the participants brought about by the workshops. This program is currently in the implementation phase. As of March 2025, a total of 10 teams have been enrolled in the I-ORCB program. Data collection for program evaluation began in June 2025 and is expected to continue until late 2026. Expected results include enhanced OR competencies among hospital teams, institutional strengthening for research, development of peer-reviewed manuscripts, and improved capacity to apply OR to service delivery challenges. The results of this program are expected to be published in 2027. The I-ORCB program applies a practical, learning-by-doing approach and is grounded in the Cooke framework for research capacity building. By integrating structured mentorship, institutional ownership, and flexible virtual learning components, the program is expected to strengthen OR culture in low- and middle-income countries and improve the delivery of eye care services in South Asia.

Chapter 4 explores the implications of Chapters 1, 2, and 3 for genomic research specifically. Increasingly, it is not only the biological samples of human pathogens that are vital for development of medicines, diagnostics, and vaccines, but genetic sequencing data (GSD). While obtaining GSD used to be slow and costly, it is now fast and declining rapidly in price. The effect of these trends are to make more genetic information available, about more people, in more parts of the world. While this problem was long anticipated and prepared for in richer countries – e.g. the Genetic Information Nondiscrimination Act in the U.S. – there is little or no infrastructure for managing genetic findings in many low- and middle-income countries. Ben Berkman, faculty at the National Institutes’ of Health Office of Bioethics, and Haley Sullivan, at the Duke Margolis Center for Health Policy, survey the risks to research participants and the ethical and practical obligations of researchers to protect genetic information in low- and middle-income countries.

Innovative, inclusive and resource-efficient screening and intervention methods are essential to address motor skill impairment among preschool children and prevent long-term consequences. This study explores the feasibility of implementing a unique motor skill program for preschool children in low-resource rural areas of South Africa, addressing the heightened risk of motor skill impairment in this demographic. Employing a quantitative pre-post quasi-experimental design with convenience sampling, the research involved assessing children using the second edition of the Movement Assessment Battery for Children (MABC-2) to evaluate their motor skills. Key objectives included assessing the program's recruitment, consent, attrition, adherence, and attendance rates, alongside determining its effect on motor skills. Children who scored less than the 5th percentile of the MABC-2 total score were included in the study and schools were randomly assigned to an intervention and control group. The Hopscotch program was facilitated by an occupational therapist over 8 weeks. Two weekly group sessions focused on gross and fine motor skills through obstacle courses, ball games and craft activities. All participants in the groups were re-assessed following the intervention. The control group received the same intervention following the post-assessment. Quantitative attendance checklists were analyzed to determine consent, assent, attrition and attendance rates. The feasibility of the MABC-2 as a data collection instrument and outcome measure was reported according to test completion rate and cost. The initial effect of the program was determined through analysis of the pre-and post-intervention MABC-2 scores using descriptive statistics while independent samples t-test were used to determine statistically significance of between-group differences. The minimal important difference (MID) for MABC-2 scores was considered to determine the clinical significance of the results. The results revealed a high consent rate (98.08%) and a 0% attrition rate, with significant attendance at program sessions (93.75%). While independent samples t-tests indicated no statistically significant differences in motor skill improvements between the intervention and control groups, analysis considering the MID demonstrated clinically significant improvements in overall motor skill proficiency and balance for the experimental group. The cost of the MABC-2 exceeded the planned budget and amounted to 77% of the total study cost. The duration for testing was one school morning for each pre- and post-test when done by five researchers. The study highlights the feasibility of conducting intervention research in low-resource settings. It notes the challenges of using the MABC-2 due to its cost and time requirements and reports on the initial effect of the program on the motor skills of the participants. Statistical significance of positive results was affected by the small sample size; however, the MID was useful in indicating clinical significance of progress made in general motor skill proficiency and balance. The feasibility study provides valuable insights to effectively plan and conduct a research project and implement a school-based motor skill intervention program in a low-resource area.

Iron supplementation may have adverse health effects in infants, probably through manipulation of the gut microbiome. Previous research in low-resource settings have focused primarily on anemic infants. This was a double blind, randomized, controlled trial of home fortification comparing multiple micronutrient powder (MNP) with and without iron. Six-month-old, non- or mildly anemic, predominantly-breastfed Kenyan infants in a rural malaria-endemic area were randomized to consume: (1) MNP containing 12.5 mg iron (MNP+Fe, n = 13); (2) MNP containing no iron (MNP−Fe, n = 13); or (3) Placebo (CONTROL, n = 7), from 6–9 months of age. Fecal microbiota were profiled by high-throughput bacterial 16S rRNA gene sequencing. Markers of inflammation in serum and stool samples were also measured. At baseline, the most abundant phylum was Proteobacteria (37.6% of rRNA sequences). The proteobacterial genus Escherichia was the most abundant genus across all phyla (30.1% of sequences). At the end of the intervention, the relative abundance of Escherichia significantly decreased in MNP−Fe (−16.05 ± 6.9%, p = 0.05) and CONTROL (−19.75 ± 4.5%, p = 0.01), but not in the MNP+Fe group (−6.23 ± 9%, p = 0.41). The second most abundant genus at baseline was Bifidobacterium (17.3%), the relative abundance of which significantly decreased in MNP+Fe (−6.38 ± 2.5%, p = 0.02) and CONTROL (−8.05 ± 1.46%, p = 0.01), but not in MNP-Fe (−4.27 ± 5%, p = 0.4445). Clostridium increased in MNP-Fe only (1.9 ± 0.5%, p = 0.02). No significant differences were observed in inflammation markers, except for IL-8, which decreased in CONTROL. MNP fortification over three months in non- or mildly anemic Kenyan infants can potentially alter the gut microbiome. Consistent with previous research, addition of iron to the MNP may adversely affect the colonization of potential beneficial microbes and attenuate the decrease of potential pathogens.

Aggregation of &gt; 104 beads due to specific protein molecules is quantified using microfluidic chips, fast lens-free microscopes, and image processing algorithms. The limit of detection, cost, and size are appropriate for COVID-19 point-of-care testing.