A Pilot Study Using Machine Learning Algorithms and Wearable Technology for the Early Detection of Postoperative Complications After Cardiothoracic Surgery.

OBJECTIVE: To evaluate whether a machine learning algorithm (i.e. the "NightSignal" algorithm) can be used for the detection of postoperative complications prior to symptom onset after cardiothoracic surgery. SUMMARY BACKGROUND DATA: Methods that enable the early detection of postoperative complications after cardiothoracic surgery are needed. METHODS: This was a prospective observational cohort study conducted from July 2021 to February 2023 at a single academic tertiary care hospital. Patients aged 18 years or older scheduled to undergo cardiothoracic surgery were recruited. Study participants wore a Fitbit watch continuously for at least 1 week preoperatively and up to 90-days postoperatively. The ability of the NightSignal algorithm-which was previously developed for the early detection of Covid-19-to detect postoperative complications was evaluated. The primary outcomes were algorithm sensitivity and specificity for postoperative event detection. RESULTS: A total of 56 patients undergoing cardiothoracic surgery met inclusion criteria, of which 24 (42.9%) underwent thoracic operations and 32 (57.1%) underwent cardiac operations. The median age was 62 (IQR: 51-68) years and 30 (53.6%) patients were female. The NightSignal algorithm detected 17 of the 21 postoperative events a median of 2 (IQR: 1-3) days prior to symptom onset, representing a sensitivity of 81%. The specificity, negative predictive value, and positive predictive value of the algorithm for the detection of postoperative events were 75%, 97%, and 28%, respectively. CONCLUSIONS: Machine learning analysis of biometric data collected from wearable devices has the potential to detect postoperative complications-prior to symptom onset-after cardiothoracic surgery.

Egocentric Image Captioning for Privacy-Preserved Passive Dietary Intake Monitoring.

Camera-based passive dietary intake monitoring is able to continuously capture the eating episodes of a subject, recording rich visual information, such as the type and volume of food being consumed, as well as the eating behaviors of the subject. However, there currently is no method that is able to incorporate these visual clues and provide a comprehensive context of dietary intake from passive recording (e.g., is the subject sharing food with others, what food the subject is eating, and how much food is left in the bowl). On the other hand, privacy is a major concern while egocentric wearable cameras are used for capturing. In this article, we propose a privacy-preserved secure solution (i.e., egocentric image captioning) for dietary assessment with passive monitoring, which unifies food recognition, volume estimation, and scene understanding. By converting images into rich text descriptions, nutritionists can assess individual dietary intake based on the captions instead of the original images, reducing the risk of privacy leakage from images. To this end, an egocentric dietary image captioning dataset has been built, which consists of in-the-wild images captured by head-worn and chest-worn cameras in field studies in Ghana. A novel transformer-based architecture is designed to caption egocentric dietary images. Comprehensive experiments have been conducted to evaluate the effectiveness and to justify the design of the proposed architecture for egocentric dietary image captioning. To the best of our knowledge, this is the first work that applies image captioning for dietary intake assessment in real-life settings.

Evaluation of Acceptability, Functionality, and Validity of a Passive Image-Based Dietary Intake Assessment Method in Adults and Children of Ghanaian and Kenyan Origin Living in London, UK.

BACKGROUND: Accurate estimation of dietary intake is challenging. However, whilst some progress has been made in high-income countries, low- and middle-income countries (LMICs) remain behind, contributing to critical nutritional data gaps. This study aimed to validate an objective, passive image-based dietary intake assessment method against weighed food records in London, UK, for onward deployment to LMICs. METHODS: Wearable camera devices were used to capture food intake on eating occasions in 18 adults and 17 children of Ghanaian and Kenyan origin living in London. Participants were provided pre-weighed meals of Ghanaian and Kenyan cuisine and camera devices to automatically capture images of the eating occasions. Food images were assessed for portion size, energy, nutrient intake, and the relative validity of the method compared to the weighed food records. RESULTS: The Pearson and Intraclass correlation coefficients of estimates of intakes of food, energy, and 19 nutrients ranged from 0.60 to 0.95 and 0.67 to 0.90, respectively. Bland-Altman analysis showed good agreement between the image-based method and the weighed food record. Under-estimation of dietary intake by the image-based method ranged from 4 to 23%. CONCLUSIONS: Passive food image capture and analysis provides an objective assessment of dietary intake comparable to weighed food records.

I2N: image to nutrients, a sensor guided semi-automated tool for annotation of images for nutrition analysis of eating episodes.

Introduction: Dietary assessment is important for understanding nutritional status. Traditional methods of monitoring food intake through self-report such as diet diaries, 24-hour dietary recall, and food frequency questionnaires may be subject to errors and can be time-consuming for the user. Methods: This paper presents a semi-automatic dietary assessment tool we developed - a desktop application called Image to Nutrients (I2N) - to process sensor-detected eating events and images captured during these eating events by a wearable sensor. I2N has the capacity to offer multiple food and nutrient databases (e.g., USDA-SR, FNDDS, USDA Global Branded Food Products Database) for annotating eating episodes and food items. I2N estimates energy intake, nutritional content, and the amount consumed. The components of I2N are three-fold: 1) sensor-guided image review, 2) annotation of food images for nutritional analysis, and 3) access to multiple food databases. Two studies were used to evaluate the feasibility and usefulness of I2N: 1) a US-based study with 30 participants and a total of 60 days of data and 2) a Ghana-based study with 41 participants and a total of 41 days of data). Results: In both studies, a total of 314 eating episodes were annotated using at least three food databases. Using I2N's sensor-guided image review, the number of images that needed to be reviewed was reduced by 93% and 85% for the two studies, respectively, compared to reviewing all the images. Discussion: I2N is a unique tool that allows for simultaneous viewing of food images, sensor-guided image review, and access to multiple databases in one tool, making nutritional analysis of food images efficient. The tool is flexible, allowing for nutritional analysis of images if sensor signals aren't available.

Adolescent Independent Eating Occasions, Dietary Intake, and Parenting Practices During the COVID-19 Pandemic: A Qualitative Study of Parents and Adolescents From Households With Low Income.

OBJECTIVE: Examine how experiencing the coronavirus disease 2019 (COVID-19) pandemic influenced adolescent independent eating occasions (iEOs) and iEO-related parenting practices from the perspective of parents and adolescents METHODS: Cross-sectional remote interviews were conducted for this basic qualitative research study. Participants were a purposive sample of multiracial/ethnic adolescents aged 11-14 years and their parents from households with low income (n = 12 dyads) representing 9 US states. The main outcome measures were iEOs and iEO-related parenting practices. Data were analyzed using directed content analysis. RESULTS: About half of the parents indicated that their adolescents had more iEOs during the COVID-19 pandemic and that there were changes in the types of foods consumed during iEOs. In contrast, most adolescents indicated their iEOs had not changed remarkably in frequency or foods consumed since the onset of the pandemic. Most parents reported no change in how they taught their adolescents about healthy food, the rules for foods/beverages permitted during iEOs, or how they monitored what their adolescents ate during iEOs; adolescent reports were in general agreement. Most parents indicated that family members were home together more often during the pandemic, which increased cooking frequency. CONCLUSIONS AND IMPLICATIONS: The effect of the COVID-19 pandemic on adolescents' iEOs varied, and the parenting practices used to influence iEOs remained stable during the pandemic. Families experienced having more time together and cooking at home more often.

Spatially-Encoding Hydrogels With DNA to Control Cell Signaling.

Patterning biomolecules in synthetic hydrogels offers routes to visualize and learn how spatially-encoded cues modulate cell behavior (e.g., proliferation, differentiation, migration, and apoptosis). However, investigating the role of multiple, spatially defined biochemical cues within a single hydrogel matrix remains challenging because of the limited number of orthogonal bioconjugation reactions available for patterning. Herein, a method to pattern multiple oligonucleotide sequences in hydrogels using thiol-yne photochemistry is introduced. Rapid hydrogel photopatterning of hydrogels with micron resolution DNA features (≈1.5 µm) and control over DNA density are achieved over centimeter-scale areas using mask-free digital photolithography. Sequence-specific DNA interactions are then used to reversibly tether biomolecules to patterned regions, demonstrating chemical control over individual patterned domains. Last, localized cell signaling is shown using patterned protein-DNA conjugates to selectively activate cells on patterned areas. Overall, this work introduces a synthetic method to achieve multiplexed micron resolution patterns of biomolecules onto hydrogel scaffolds, providing a platform to study complex spatially-encoded cellular signaling environments.

Parenting Practices Are Associated With Adolescent Food Choices During Independent Eating Occasions.

BACKGROUND: Frequency of independent eating occasions (iEOs) has been linked to intake of unhealthy foods and overweight or obesity among adolescents. Parenting practices involving modeling healthy food intake and making healthy foods available have been associated with healthy food intake among adolescents; however, little is known about these associations during iEOs. OBJECTIVE: To determine whether parenting practices involving structure (monitoring, availability, modeling, and expectations), lack of structure (indulgence), and autonomy support reported by adolescents or parents were associated with adolescent iEO intake of junk foods, sugar-sweetened beverages (SSBs), sugary foods, and fruit and vegetables. DESIGN: Cross-sectional study measuring parenting practices and adolescent iEO food choices via an online survey and adapted food frequency questionnaire. PARTICIPANTS/SETTING: Parent/adolescent dyads (n = 622) completed surveys (November-December 2021) using a national Qualtrics panel database. Adolescents were 11 to 14 years of age and had iEOs at least weekly. MAIN OUTCOME MEASURES: Primary measures included parent- and adolescent-reported frequency of food parenting practices and adolescent-reported iEO intake of junk foods, sugary foods, SSBs, and fruits and vegetables. STATISTICAL ANALYSES PERFORMED: Multivariable linear regression models were used to examine associations between parenting practices and iEO intake of foods/beverages, adjusting for adolescent's age, sex, race and ethnicity, iEO frequency, parent's education and marital status, and household food security status. Bonferroni multiple comparison corrections were conducted. RESULTS: More than half of parents were female (66%) and 35 to 64 years of age (58%). Adolescents/parents identified as White/Caucasian (44%/42%), Black/African American (28%/27%), Asian (21%/23%), and Hispanic ethnicity (42%/42%). Positive associations were observed among adolescent-reported and parent-reported autonomy support, monitoring, indulgence and expectations parenting practices, and adolescent-reported daily iEO intake frequencies of junk foods, sugary foods, and fruits and vegetables (P < 0.001). CONCLUSIONS: Structural and autonomy support parenting practices were positively associated with both healthy and unhealthy iEO food intake by adolescents. Interventions to improve adolescent iEO intake could promote positive practices associated with healthy food consumption.

Factors associated with dietary acculturation among international students at the University of Georgia.

OBJECTIVE: Western diet is associated with chronic disease risk, and degree of dietary acculturation can impact susceptibility. This study sought to understand the factors associated with changes in food consumption habits among international students at a large public university in the southern US. PARTICIPANTS: A convenience sample of 173 international students representing 41 countries at The University of Georgia participated in the survey. METHODS: This cross-sectional online survey assessed dietary habits, perception of healthy eating, and level of acculturation using previously validated measures. RESULTS: Highest number of participants were from China (19.2%), 89.0% were graduate students with an average age of 27.5 ± 4.83 years. The majority (62.0%) of participants were dietary acculturated with affordability and accessibility determining types of food consumption, as fewer whole foods and more processed foods were consumed in the U.S. CONCLUSIONS: Findings suggest dietary acculturation may be driven by economic factors, making the transition to Westernized food items a convenient and cost-effective choice among international students.

Relationship between Family Racial/Ethnic Backgrounds, Parenting Practices and Styles, and Adolescent Eating Behaviors.

Obesity is more prevalent among racial minority children in the United States, as compared to White children. Parenting practices can impact the development of children's eating behaviors and habits. In this study, we investigated the relationships among racial/ethnic backgrounds, parenting practices and styles, and eating behaviors in adolescents. Fifty-one parent-adolescent dyads were interviewed to characterize parenting practices and styles, as well as the consumption of dairy, fruits and vegetables, and unhealthy snacks. Height and weight were measured to calculate parent BMI and adolescent BMI-for-age percentiles. Three parenting practice categories-modeling, authoritative, and authoritarian-were found to be related to race/ethnicity. A higher score in authoritarian parenting practices was related to higher BMI percentiles among African American adolescents, whereas a higher score in monitoring practices was related to lower BMI percentiles among non-Hispanic White adolescents. Modeling, reasoning, and monitoring led to higher consumption of fruits and vegetables among adolescents; however, the consumption of unhealthy snacks was higher with rule-setting and lower with reasoning and authoritative practices. Finally, an analysis of the relationships between environmental factors and snack intake showed that adolescents consumed significantly more unhealthy snacks when performing other activities while eating. In conclusion, the findings from this study suggest that families' racial heritages are related to their parenting practices, BMI percentiles, and their adolescents' food consumption and eating behaviors. The results of this study can be used to develop and improve adolescent nutrition education and interventions with consideration of their racial/ethnic backgrounds.

Work-loop contractions reveal that the afterload-dependent time course of cardiac Ca2+ transients is modulated by preload.

Preload and afterload dictate the dynamics of the cyclical work-loop contraction that the heart undergoes in vivo. Cellular Ca2+ dynamics drive contraction, but the effects of afterload alone on the Ca2+ transient are inconclusive. To our knowledge, no study has investigated whether the putative afterload dependence of the Ca2+ transient is preload dependent. This study is designed to provide the first insight into the Ca2+ handling of cardiac trabeculae undergoing work-loop contractions, with the aim to examine whether the conflicting afterload dependency of the Ca2+ transient can be accounted for by considering preload under isometric and physiological work-loop contractions. Thus, we subjected ex vivo rat right-ventricular trabeculae, loaded with the fluorescent dye Fura-2, to work-loop contractions over a wide range of afterloads at two preloads while measuring stress, length changes, and Ca2+ transients. Work-loop control was implemented with a real-time Windkessel model to mimic the contraction patterns of the heart in vivo. We extracted a range of metrics from the measured steady-state twitch stress and Ca2+ transients, including the amplitudes, time courses, rates of rise, and integrals. Results show that parameters of stress were afterload and preload dependent. In contrast, the parameters associated with Ca2+ transients displayed a mixed dependence on afterload and preload. Most notably, its time course was afterload dependent, an effect augmented at the greater preload. This study reveals that the afterload dependence of cardiac Ca2+ transients is modulated by preload, which brings the study of Ca2+ transients during isometric contractions into question when aiming to understand physiological Ca2+ handling.NEW & NOTEWORTHY This study is the first examination of Ca2+ handling in trabeculae undergoing work-loop contractions. These data reveal that reducing preload diminishes the influence of afterload on the decay phase of the cardiac Ca2+ transient. This is significant as it reconciles inconsistencies in the literature regarding the influence of external loads on cardiac Ca2+ handling. Furthermore, these findings highlight discrepancies between Ca2+ handling during isometric and work-loop contractions in cardiac trabeculae operating at their optimal length.

Adherence to the Dietary Approaches to Stop Hypertension (DASH) diet is associated with low levels of insulin resistance among heart failure patients.

BACKGROUND AND AIMS: Heart failure (HF) patients are at risk of developing type 2 diabetes. This study examined the association between adherence to the Dietary Approaches to Stop Hypertension (DASH) diet and insulin resistance among U.S. adults with HF. METHODS AND RESULTS: Using data from National Health and Nutrition Examination Survey 1999-2016 cycles, we included 348 individuals aged 20+ years with HF and no history of diabetes. DASH diet adherence index quartile 1 indicated the lowest and quartile 4 indicated the highest adherence. The highest level of insulin resistance was defined by the upper tertile of the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR). Associations between level of insulin resistance and DASH diet adherence and its linear trends were examined using logistic regressions. Trend analyses showed that participants in upper DASH diet adherence index quartiles were more likely older, female, non-Hispanic White, of normal weight, and had lower levels of fasting insulin than those in lower quartiles. Median values of HOMA-IR from lowest to highest DASH diet adherence index quartiles were 3.1 (interquartile range, 1.8-5.5), 2.9 (1.7-5.6), 2.1 (1.1-3.7), and 2.1 (1.3-3.5). Multivariable logistic analyses indicated that participants with the highest compared to the lowest DASH adherence showed 77.1% lower odds of having the highest level of insulin resistance (0.229, 95% confidence interval: 0.073-0.716; p = 0.017 for linear trend). CONCLUSION: Good adherence to the DASH diet was associated with lower insulin resistance among community-dwelling HF patients. Heart healthy dietary patterns likely protect HF patients from developing type 2 diabetes.

Feasibility of the automatic ingestion monitor (AIM-2) for infant feeding assessment: a pilot study among breast-feeding mothers from Ghana.

OBJECTIVE: Passive, wearable sensors can be used to obtain objective information in infant feeding, but their use has not been tested. Our objective was to compare assessment of infant feeding (frequency, duration and cues) by self-report and that of the Automatic Ingestion Monitor-2 (AIM-2). DESIGN: A cross-sectional pilot study was conducted in Ghana. Mothers wore the AIM-2 on eyeglasses for 1 d during waking hours to assess infant feeding using images automatically captured by the device every 15 s. Feasibility was assessed using compliance with wearing the device. Infant feeding practices collected by the AIM-2 images were annotated by a trained evaluator and compared with maternal self-report via interviewer-administered questionnaire. SETTING: Rural and urban communities in Ghana. PARTICIPANTS: Participants were thirty eight (eighteen rural and twenty urban) breast-feeding mothers of infants (child age ≤7 months). RESULTS: Twenty-five mothers reported exclusive breast-feeding, which was common among those < 30 years of age (n 15, 60 %) and those residing in urban communities (n 14, 70 %). Compliance with wearing the AIM-2 was high (83 % of wake-time), suggesting low user burden. Maternal report differed from the AIM-2 data, such that mothers reported higher mean breast-feeding frequency (eleven v. eight times, P = 0·041) and duration (18·5 v. 10 min, P = 0·007) during waking hours. CONCLUSION: The AIM-2 was a feasible tool for the assessment of infant feeding among mothers in Ghana as a passive, objective method and identified overestimation of self-reported breast-feeding frequency and duration. Future studies using the AIM-2 are warranted to determine validity on a larger scale.

A Novel Approach to Dining Bowl Reconstruction for Image-Based Food Volume Estimation.

Knowing the amounts of energy and nutrients in an individual's diet is important for maintaining health and preventing chronic diseases. As electronic and AI technologies advance rapidly, dietary assessment can now be performed using food images obtained from a smartphone or a wearable device. One of the challenges in this approach is to computationally measure the volume of food in a bowl from an image. This problem has not been studied systematically despite the bowl being the most utilized food container in many parts of the world, especially in Asia and Africa. In this paper, we present a new method to measure the size and shape of a bowl by adhering a paper ruler centrally across the bottom and sides of the bowl and then taking an image. When observed from the image, the distortions in the width of the paper ruler and the spacings between ruler markers completely encode the size and shape of the bowl. A computational algorithm is developed to reconstruct the three-dimensional bowl interior using the observed distortions. Our experiments using nine bowls, colored liquids, and amorphous foods demonstrate high accuracy of our method for food volume estimation involving round bowls as containers. A total of 228 images of amorphous foods were also used in a comparative experiment between our algorithm and an independent human estimator. The results showed that our algorithm overperformed the human estimator who utilized different types of reference information and two estimation methods, including direct volume estimation and indirect estimation through the fullness of the bowl.

Prevalence and trends of type 2 diabetes mellitus and prediabetes among community-dwelling heart failure patients in the United States.

AIMS: This study estimated national prevalence and trends of diagnosed and undiagnosed type 2 diabetes mellitus (T2DM) and prediabetes among heart failure (HF) patients in the U.S. METHODS: This cross-sectional study included 527 participants aged 20+ years with a diagnosis of HF, using data from the National Health and Nutrition Examination Survey 2005-2016. We assessed prevalence estimates of diagnosed and undiagnosed T2DM and prediabetes stratified by age-standardized sociodemographic and health characteristics. Trends of T2DM and prediabetes prevalence were examined using logistic regressions. RESULTS: Prevalence rates of diagnosed and undiagnosed T2DM among HF patients were 34.7% (95% confidence interval (CI), 29.2-40.3%) and 12.8% (95% CI, 9.2-16.9%), respectively. Prediabetes affected 39.1% (95% CI, 33.6-44.9%) of HF patients. Prevalence estimates of diagnosed T2DM were significantly different between non-Hispanic White (20.1% [95% CI, 13.5-27.6%]) and Hispanic participants (52.1% [95% CI, 35.9-68.0%]) (P < 0.001). The prevalence of T2DM and prediabetes did not significantly change between 2005 and 2016. CONCLUSIONS: Prevalence rates of T2DM and prediabetes among community-dwelling HF patients in the U.S. remained high between 2005 and 2016. Prevention of and targeted intervention for T2DM among at-risk HF patients is needed, particularly among those of Hispanic origin.

Minimum 5-Year Outcomes of a Multicenter, Prospective, Randomized Control Trial Assessing Clinical and Radiological Outcomes of Patient-Specific Instrumentation in Total Knee Arthroplasty.

BACKGROUND: Patient-specific instrumentation (PSI) was developed to produce more accurate alignment of components and consequently improve clinical outcomes when used in total knee arthroplasty. We compare radiological accuracy and clinical outcomes at a minimum of 5-year follow-up between patients randomized to undergo total knee arthroplasty performed using PSI or traditional cutting block techniques. METHODS: This multicenter, randomized control trial included patients blinded to the technique 1used. Outcome measures were coronal alignment measured radiologically, Euroqol-5D, Oxford knee score, and International Knee Society Score measured at 1- and 5-year follow-up. RESULTS: At a minimum 5-year follow-up, there were 38 knees in the PSI group and 39 in the conventional instrumentation group for analysis. Baseline demographics and clinical outcome scores were matched between groups. Overall, there was no significant difference in the coronal femoral angle (P = .59), coronal tibial angle (P = .37), tibiofemoral angle (P = .99), sagittal femoral angle (P = .34), or the posterior tibia slope (P = .12) between knees implanted using PSI and those implanted with traditional cutting blocks. On the measurement of coronal alignment, intraobserver reliability tests demonstrated substantial agreement (k = 0.64). Clinical outcomes at both 1-year and 5-year follow-up demonstrated statistically significant and clinically relevant improvement in scores from baseline in both groups, but no difference could be detected between the Euroqol-5D (P = .78), Oxford knee score (P = .24), or International Knee Society Score (P = .86) between the 2 groups. CONCLUSION: This study has shown no additional benefit to PSI in terms of improved alignment or functional outcomes at minimum 5-year follow-up over traditional techniques.

Athermal, Chemically Triggered Release of RNA from Thioester Nucleic Acids.

An athermal approach to mRNA enrichment from total RNA using a self-immolative thioester linked nucleic acids (TENA) is described. Oligo(thymine) (oT) TENA has a six-atom spacing between bases which allowed TENA to selectively base-pair with polyadenine RNA. As a result of the neutral backbone of TENA and the hydrophobicity of the octanethiol end group, oT TENA is water insoluble and efficiently pulled down 93±2 % of EGFP mRNA at a concentration of 10 ng µL-1 . Self-immolative degradation of TENA upon ambient temperature exposure to nucleophilic buffer components (Tris, DTT) allowed recovery of 55±27 ng of mRNA from 3.1 µg of total RNA, which was not statistically different from the amount recovered using Dynabeads® mRNA DIRECT Kit (89±24 ng). Gene expression as measured by RT-qPCR was comparable for both enrichment methods, suggesting that the mild conditions required for enrichment of mRNA using oT TENA are compatible with RT-qPCR and other downstream molecular biology applications.

Simultaneous Brightfield, Fluorescence, and Optical Coherence Tomographic Imaging of Contracting Cardiac Trabeculae Ex Vivo.

In cardiac muscle, intracellular Ca2+ transients activate contractile myofilaments, causing contraction, macroscopic shortening, and geometric deformation. Our understanding of the internal relationships between these events has been limited because we can neither 'see' inside the muscle nor precisely track the spatio-temporal nature of excitation-contraction dynamics. To resolve these problems, we have constructed a device that combines a suite of imaging modalities. Specifically, it integrates a brightfield microscope to measure local changes of sarcomere length and tissue strain, a fluorescence microscope to visualize the Ca2+ transient, and an optical coherence tomograph to capture the tissue's geometric changes throughout the time-course of a cardiac cycle. We present here the imaging infrastructure and associated data collection framework. Data are collected from isolated rod-like tissue structures known as trabeculae carneae. In our instrument, a pair of position-controlled platinum hooks hold each end of an ex vivo muscle sample while it is continuously superfused with nutrient-rich saline solution. The hooks are under independent control, permitting real-time control of muscle length and force. Lengthwise translation enables the piecewise scanning of the sample, overcoming limitations associated with the relative size of the microscope imaging window (540 µm by 540 µm) and the length of a typical trabecula (>2000 µm). Platinum electrodes at either end of the muscle chamber stimulate the trabecula at a user-defined rate. We exploit the stimulation signal as a trigger for synchronizing the data from each imaging window to reconstruct the entire sample twitching under steady-state conditions. Applying image-processing techniques to these brightfield imaging data provides tissue displacement and sarcomere length maps. Such a collection of data, when incorporated into an experiment-modeling pipeline, will provide a deeper understanding of muscle contractile homogeneity and heterogeneity in physiology and pathophysiology.

Food/Non-Food Classification of Real-Life Egocentric Images in Low- and Middle-Income Countries Based on Image Tagging Features.

Malnutrition, including both undernutrition and obesity, is a significant problem in low- and middle-income countries (LMICs). In order to study malnutrition and develop effective intervention strategies, it is crucial to evaluate nutritional status in LMICs at the individual, household, and community levels. In a multinational research project supported by the Bill & Melinda Gates Foundation, we have been using a wearable technology to conduct objective dietary assessment in sub-Saharan Africa. Our assessment includes multiple diet-related activities in urban and rural families, including food sources (e.g., shopping, harvesting, and gathering), preservation/storage, preparation, cooking, and consumption (e.g., portion size and nutrition analysis). Our wearable device ("eButton" worn on the chest) acquires real-life images automatically during wake hours at preset time intervals. The recorded images, in amounts of tens of thousands per day, are post-processed to obtain the information of interest. Although we expect future Artificial Intelligence (AI) technology to extract the information automatically, at present we utilize AI to separate the acquired images into two binary classes: images with (Class 1) and without (Class 0) edible items. As a result, researchers need only to study Class-1 images, reducing their workload significantly. In this paper, we present a composite machine learning method to perform this classification, meeting the specific challenges of high complexity and diversity in the real-world LMIC data. Our method consists of a deep neural network (DNN) and a shallow learning network (SLN) connected by a novel probabilistic network interface layer. After presenting the details of our method, an image dataset acquired from Ghana is utilized to train and evaluate the machine learning system. Our comparative experiment indicates that the new composite method performs better than the conventional deep learning method assessed by integrated measures of sensitivity, specificity, and burden index, as indicated by the Receiver Operating Characteristic (ROC) curve.

Synthesis and Characterization of Click Nucleic Acid Conjugated Polymeric Microparticles for DNA Delivery Applications.

Microparticle-mediated nucleic acid delivery is a popular strategy to achieve therapeutic outcomes via antisense gene therapy. However, current methods used to fabricate polymeric microparticles suffer from suboptimal properties such as particle polydispersity and low encapsulation efficiency. Here, a new particulate delivery system based on step-growth thiol-Michael dispersion polymerization is reported in which a low polydispersity microparticle is functionalized with a synthetic nucleic acid mimic, namely, click nucleic acids (CNA). CNA oligomers, exhibiting an average length of approximately four nucleic acid repeat units per chain for both adenine and thymine bases, were successfully conjugated to excess thiols present in the microparticles. Effective DNA loading was obtained by simple mixing, and up to 6 ± 2 pmol of complementary DNA/mg of particle was achieved, depending on the length of DNA used. In addition, DNA loading was orders of magnitude less for noncomplementary sequences and sequences containing an alternating base mismatch. The DNA release properties were evaluated, and it was found that release could be triggered by sudden changes in temperature but was unaffected over a range of pH. Finally, phagocytosis of loaded microparticles was observed by confocal microscopy and corroborated by an increase in cellular metabolic activity up to 90%. Overall, this work suggests that CNA functionalized microparticles could be a promising platform for controlled DNA delivery.

Parenting Practices and Adolescents' Eating Behaviors in African American Families.

Parents play an important role in developing the eating behaviors of their children by adopting specific parenting practices. As the prevalence of obesity is high amongst African American adolescents, investigations into associations of specific parenting practices and adolescents' eating behaviors are essential. In this exploratory study, 14 African American parent-adolescent dyads were interviewed to characterize the influence of eight different parenting practices on the consumption of three main food categories (dairy, fruits and vegetables, and unhealthy snacks). The results revealed that authoritarian parenting practices were correlated with a higher BMI percentile in adolescents, whereas modeling and monitoring are correlated with a higher parent BMI. In addition, reasoning, monitoring, modeling, and authoritative parenting practices were associated with less unhealthy snack consumption among adolescents. Reasoning and monitoring were the only parenting practices associated with higher fruit and vegetable consumption. Finally, a significant correlation was found between eating fruits and vegetables and unhealthy snacks and the location of eating. In conclusion, different parenting practices and environmental factors may impact BMI and food consumption of African American dyads. The results of this study can be used to guide improvement in, and/or development of, nutritional education interventions considering the cultural differences of racial minorities.