The timing and types of food people eat, along with daily fluctuations in in these parameters, are important factors influencing health and well-being. However, there is limited data on how eating patterns remain consistent over multiple days. To address this gap, we conducted an exploratory, observational analysis of over 20,000 adults, who recorded more than 2.5 million food logs collected over two weeks via the myCircadianClock app. Our analysis reveals significant variability in food timing and diversity. The time window during which 95% of food and beverages were consumed during the 2 weeks ranged from 10 hours 54 minutes for the lowest decile to over 16 hours for the highest. The median number of unique food and beverage items consumed over the two weeks varied from 20 to 86, but only a subset of these items was consistently eaten on multiple days. Many common foods were regularly consumed at specific times of the day, and factors like age, gender, and work schedules influenced both eating patterns and food choices. These findings provide a foundation for utilizing longitudinal food records in nutrition and lifestyle research to enhance our understanding of human behavior and health.

Advancements in fabrication methods have shaped new computing device technologies. Among these methods, depositing electrical contacts to the channel material is fundamental to device characterization. Novel layered and 2D materials are promising for next-generation computing electronic channel materials. Direct-write printing of conductive inks is introduced as a surprisingly effective, significantly faster, and cleaner method to contact different classes of layered materials, including graphene (semi-metal), MoS2 (semiconductor), Bi-2212 (superconductor), and Fe5GeTe2 (metallic ferromagnet). Based on the electrical response, the quality of the printed contacts is comparable to what is achievable with resist-based lithography techniques. These devices are tested by sweeping gate voltage, temperature, and magnetic field to show that the materials remain pristine post-processing. This work demonstrates that direct-write printing is an agile method for prototyping and characterizing the electrical properties of novel layered materials.

Additive manufacturing has the potential to fabricate custom parts with complex shapes. For syringe printing, there is a possibility for printing filaments consisting of different materials on a single tool. Additively manufactured electronics is a major field of investigative research, where filaments contain nanoparticles to tailor properties, such as metal to improve magnetic permeability. This study investigates syringe printing parts with high magnetic permalloy (Ni80Fe20) nanoparticle content (>35 vol%) and the properties of inductors printed from these inks. Two different metal alloy particle sizes of 250 nm and 30 nm are synthesized to observe the effect of particle size on stability. Zeta potential and settling behavior are observed to discern how coating procedures enhance particle stability in water. Permalloy nanoparticle inks are concentrated with polyethylene glycol (PEG) to increase viscosity and glycerol to decrease evaporation rates while printing. It is found that PEG and glycerol stabilize 30 nm permalloy nanoparticles in addition to increasing ink viscosity. Permalloy nanoparticle inks are printed into toroid shapes demonstrating the feasibility of fabricating useful three-dimensional magnetic structures. These inductors exhibited an inductance of 180 nH at 30 MHz.

Additive manufacturing has the potential to simplify fabrication processes by using a single apparatus that exchanges printable material at the print head to create complex shapes. Circuit components can be made of various materials such as magnetic materials, which are specifically used for many applications, including inductors. Few syringe printable magnetic inks have been explored, and even fewer to create a final product with high magnetic content compared to polymer content (>90 vol %). In this study, syringe printable, colloidal magnetic inks are made using both iron oxide and MnZn doped ferrite nanoparticles by stabilizing them with poly(acrylic acid) (PAA) and adding a free polymer poly(ethylene oxide) (PEO) of various molecular weights and glycerol to control ink viscosity and evaporation rates. Printability is further explained using complex rheology. MnZn doped ferrite inks are printed into toroids and sintered at 1400 degrees C to increase magnetic permeability. A sintered toroid is constructed into an inductor device and characterized using a Vector Network Analyzer (VNA), which exhibits an inductance of 4.26 mu H at 8.5 MHz. This study lays out a template for ferrite inks with the potential to be fabricated into useful passive electronic devices.

We report the design, fabrication, and experimental characterization of an optically transparent printed planar inverted-F antenna (PIFA) operating at 2.45 GHz using the aerosol jet (AJ) printing method. The proposed antenna was fabricated using a clear conductive ink on glass and Delrin. The antenna exhibits a wide fractional bandwidth (FBW) of 20% centered at 2.45 GHz, with a peak realized gain of −3.6 dBi and transparency of ~80%. The proposed fabrication method provides a cost-effective and scalable solution for manufacturing transparent antennas with potential applications in wireless communication, sensing, and wearable devices operating at mmWave frequencies higher than 30 GHz.

To understand the reliability and repairablityof electronics printed using the AJP process, through experimental and computational modeling, to take full advantage of this technology and realize its industrial potential. This work is sponsored by the members of the CALCE at the University of Maryland, College Park and Laboratory for Physical Science.

In the absence of electric light, sleep for humans typically starts soon after dusk and at higher latitudes daily sleep timing changes seasonally as photoperiod changes. However, access to electric light shields humans from natural photoperiod changes, and whether seasonal changes in sleep occur despite this isolation from the natural light-dark cycle remains a matter of controversy. We measured sleep timing in over 500 university students living in the city of Seattle, WA (47.6 degrees N) throughout the four seasons; we show that even when students are following a school schedule, sleep timing is delayed during the fall and winter. For instance, during the winter school days, students fell asleep 35 min later and woke up 27 min later (under daylight-savings time) than students during the summer school days, a change that is an hour larger relative to solar midnight. Furthermore, chronotype defined by mid-sleep on free days corrected for oversleep (MSFc), an indirect estimate of circadian phase, was more than 30 min later in the winter compared with the summer. Analysis of the effect of light exposure showed that the number of hours of light exposure to at least 50 lux during the daytime was a stronger predictor of MSFc than the exposure time to this illuminance after dusk. Specifically, MSFc was advanced by 30 min for each additional hour of light exposure during daytime and delayed by only 15 min for each additional hour of postdusk exposure to light. Additionally, the time of the day of exposure to high light intensities was more predictive of MSFc when daytime exposure was considered than when exposure for the full 24-h day was considered. Our results show that although sleep time is highly synchronized to social time, a delayed timing of sleep is evident during the winter months. They also suggest that daily exposure to daylight is key to prevent this delayed phase of the circadian clock and thus circadian disruption that is typically exacerbated in high-latitude winters.

Aerosol-Jet Printing (AJP) technology, applied to the manufacturing of printed hybrid electronics (PHE) devices, has the capability to fabricate highly complex structures with resolution in the tens-of-microns scale, creating new possibilities for the fabrication of electronic devices and assemblies. The widespread use of AJP in fabricating PHE and package-level electronics necessitates a thorough assessment of not only the performance of AJP printed electronics but also their reliability under different kinds of life-cycle operational and environmental stresses. One important hindrance to the reliability and long-term performance of such AJP electronics is electrochemical migration (ECM). ECM is an important failure mechanism in electronics under temperature and humidity conditions because it can lead to conductive dendritic growth, which can cause dielectric breakdown, leakage current, and unexpected short circuits. In this paper, the ECM propensity in conductive traces printed with AJP process, using silver-nanoparticle (AgNP) based inks, was experimentally studied using temperature-humidity-bias (THB) testing of printed test coupons. Conductive dendritic growth with complex morphologies was observed under different levels of temperature, humidity, and electric bias in the THB experiments. Weibull statistics are used to quantify the failure data, along with the corresponding confidence bounds to capture the uncertainty of the Weibull distribution. A nonmonotonic relationship between time-to-failure and electric field strength was noticed. An empirical acceleration model for ECM is proposed, by combining the classical Peck's model with a quadratic polynomial dependence on electric field strength. This model provides good estimate of acceleration factors for use conditions where the temperature, humidity, and electrical field are within the tested range, but should be extrapolated with care beyond the tested range.

Over a quarter of the workforce in industrialized countries does shift work, which increases the risk for car-diometabolic disease. Yet shift workers are often excluded from lifestyle intervention studies to reduce this risk. In a randomized control trial with 137 firefighters who work 24-h shifts (23-59 years old, 9% female), 12 weeks of 10-h time-restricted eating (TRE) was feasible, with TRE participants decreasing their eating win-dow (baseline, mean 14.13 h, 95% CI 13.78-14.47 h; intervention, 11.13 h, 95% CI 10.73-11.54 h, p = 3.29E-17) with no adverse effects, and improved quality of life assessed via SF-36 (ClinicalTrials.gov: NCT03533023). Compared to the standard of care (SOC) arm, TRE significantly decreased VLDL particle size. In participants with elevated cardiometabolic risks at baseline, there were significant reductions in TRE compared to SOC in glycated hemoglobin A1C and diastolic blood pressure. For individuals working a 24-h shift schedule, TRE is feasible and can improve cardiometabolic health, especially for individuals with increased risk.

Calorie restriction (CR) and time-restricted eating (TRE) are distinctly different dietary management strategies with overlapping health outcomes. After two years of CR, healthy participants in the Comprehensive Assessment of Long-Term Effects of Reducing Intake of Energy (CALERIE) study showed significant weight-loss relative to the ad libitum intake control group and achieved 12% CR on average. Preclinical rodent studies have shown that sustaining a consistent eating interval of 8-12 h between the first and last calories of each day-without reducing daily calorie intake-can impart health benefits that partly overlap with those imparted by CR. Preclinical CR protocols often inadvertently restrict eating interval, and conversely, clinical studies of TRE often inadvertently result in modest CR. Other factors related to daily timing of food intake, such as breakfast skipping, and early food intake also impact health outcomes. These observations have raised the possibility that CR protocols can be further optimized by adopting relevant aspects of eating patterns to boost weight loss and health outcomes. With a goal to inform CR protocols that aim to optimize eating patterns, the objective of this secondary analysis was to test aspects of daily timing of food intake associated with greater weight loss in the CALERIE study participants. We found no difference in the daily time window of energy intake between the CR and control arms. In the CALERIE trial, weight change was used as a proxy for adherence to CR, and hence we used linear models to test the relationships among CR, weight loss, and temporal aspects of daily eating pattern. We found that CR alone could explain 41% of the variance in weight loss. We tested the contribution of eating interval, time to 50% daily calorie intake, and day-to-day shifts in the time of the first (breakfast) or last meal consumed. We found that eating interval and variation in the timing of the first and last meals significantly influenced weight loss after controlling for CR. Our models suggest that shorter eating intervals are associated with greater CR (1% of the variance explained) and facilitate additional weight loss. Our models suggest that less day to day variation in first mealtime is directly associated with weight loss (6% of the variance explained). More regular first meal timing is also associated with greater CR (2% of the variance explained). Likewise, regular timing of the last daily meal is directly associated with weight loss (1% of the variance explained) and greater CR (1% of the variance explained). The time to 50% of daily calorie intake or consuming half the caloric intake earlier in the day is associated with additional CR (2% of the variance explained). In summary, these secondary analyses on CALERIE data suggest that - in order to maximize CR and weight loss - future CR protocols should encourage participants to adopt consistent timing of their first and last meals, a shorter eating window, and earlier consumption of food.

In this study, temperature-humidity-bias (THB) testing and water droplet (WD) testing have been conducted to study electro-chemical migration (ECM) and dendrite formation across features in aerosol jet printed (AJP) conductor patterns. Test specimen design and testing conditions were guided by industrial standards and related research studies. Time-to-failure (TTF) for AJP printed silver patterns is found to be much smaller than that for conventional copper patterns in THB testing, under identical testing conditions. Furthermore, TTF for dendrite growth between neighboring biased conductors at constant temperature and humidity conditions was found to have a non-monotonic dependence on the electric potential gradient. The dendrite density was found to vary significantly with different applied voltage gradients in both THB testing and WD testing. Those observations can help to guide future investigation and life-prediction modeling of AJP printed electronics subjected to combined temperature, humidity, and voltage stresses.

The current technologies of 3D printing have a huge potential in the domain of printed radio frequency (RF) electronic components, such as resistors, capacitors, inductors, and transmission lines. In this paper, we present the design, fabrication, and characterization of fully 3-D printed conical inductors for broadband applications. The cores of these conical-shaped inductors were all printed by engineered magnetic/dielectric materials: the first one with a polymer core was printed by the aerosol-jet (AJ) printing technology as a reference, the second one with an iron-cobalt core fabricated by a paste-extrusion (PE) method using our developed iron-cobalt-based magnetic ink, and the third one with a core fabricated (by the PE method) using iron-based powder. The conical inductor was placed at a 45 degrees angle by mounting it on a lattice support structure, and this configuration ensured a reduction of the parasitic capacitance between the inductor and the substrate. As a result, it was possible, to achieve a resonant-free broadband performance beyond the Ka-band (26.5-40 GHz), thereby outperforming the commercial off-the-shelf (COTS) products. Numerical simulations were also performed to explain the inductor performance and pinpoint the optimal model parameters. As suggested by the lumped circuit model, the operational frequency of the fully 3D printed iron-powder-based-core inductor could be as high as 67 GHz, which is nearly two times larger than the commercial iron core inductor.

Aerosol-Jet Printing (AJP) provides a new method for electronic component manufacturing. Understanding the reliability of electronics printed using the AJP process is essential to take full advantage of this technology and realize its industrial potential. In the current study, we have designed and tested AJP printed samples and conducted failure analysis of those samples that have exhibited early failures. Failures first occurred in the short traces that connect the main traces to the silver pads, due to local stress-raisers caused by local geometric features in the printing geometry. Thermal-Mechanical Finite-Element-Modeling (FEM) has been performed to analyze the cyclic history of thermo-mechanical stress distribution and plastic strain distribution.

INTRODUCTION:Career firefighters experience chronic circadian rhythm disruption, increasing their risk of cardiometabolic disease. The recent discovery that eating patterns regulate circadian rhythmicity in metabolic organs has raised the hypothesis that maintaining a consistent daily cycle of eating and fasting can support circadian rhythms and reduce disease risks. Preclinical animal studies and preliminary clinical trials have shown promising effects of time-restricted eating (TRE) to reduce disease risk without compromising physical performance. However, there is a lack of research on TRE in shift workers including firefighters. This study aims to investigate the feasibility and efficacy of 10-hour TRE on health parameters that contribute to cardiometabolic disease risks among career firefighters who work on a 24-hour shift schedule.METHODS AND ANALYSES:The Healthy Heroes Study is a randomised controlled parallel open-label clinical trial with 150 firefighters over 1 year. Firefighters are randomised with a 1:1 ratio to either the control or intervention group. The control group receives Mediterranean diet nutritional counselling (standard of care, 'SOC'). The intervention group receives the same SOC and a self-selected 10-hour TRE window. After the 2-week baseline, participants enter a 3-month monitored intervention, followed by a 9-month self-guided period with follow-up assessments. The impact of TRE on blood glucose, body weight, body composition, biomarkers (neuroendocrine, inflammatory and metabolic), sleep and mood is evaluated. These assessments occur at baseline, at the end of intervention and at 6, 9 and 12-month follow-ups. Temporal calorie intake is monitored with the smartphone application myCircadianClock throughout the study. Continuous glucose monitors, wrist-worn actigraphy device and questionnaires are used to monitor glucose levels, activity, sleep and light exposure.ETHICS AND DISSEMINATION:The study was approved by the Institutional Review Boards of the University of California San Diego and the Salk Institute for Biological Studies. Results will be disseminated through peer-reviewed manuscripts, reports and presentations.TRIAL REGISTRATION NUMBER:NCT03533023; Pre result.

In contrast to intentionally restricting energy intake, restricting the eating window may be an option for treating obesity. By comparing time‐restricted eating (TRE) with an unrestricted (non‐TRE) control, it was hypothesized that TRE facilitates weight loss, alters body composition, and improves metabolic measures.

Abstract Introduction Time-restricted eating (TRE), limiting food intake to a consistent daily window, is emerging as a novel weight loss intervention but impact of TRE on sleep remains unclear. Prior studies reported mixed results but are limited by subjective sleep measurements and lack of a randomized control group. Thus, we examined changes in actigraphy-measured sleep following a 12-week TRE protocol. Methods Participants were 20 adults ages 18-65 years with BMI ≥24kg/m2. Participants were randomized to either TRE (8-hour eating window) or non-TRE (typical eating). At baseline and follow-up, all participants had anthropometric measurements, oral glucose tolerance test, logged eating occasions in a smartphone application, and wore an ActiGraph Link for two weeks. Independent samples t-tests compared groups on actigraphy-estimated sleep variables. Pearson correlations examined associations between sleep variables with health outcomes. Results The TRE (N=11) and non-TRE groups (N=9) were predominantly female and had a baseline eating window of approximately 15 hours. There were no differences in actigraphy-assessed sleep variables at baseline or follow-up between groups. Participants did not significantly change their sleep from baseline to follow-up. Median weekday sleep duration was 6.2 hours at follow-up for all participants, suggesting insufficient sleep compared to the recommended 7-9 hours of sleep. Participants who obtained greater than the median weekday sleep duration at follow-up had significantly lower BMI, better insulin sensitivity (HOMA and Matsuda Index), and greater percent improvement in insulin sensitivity. Conclusion Our data show that TRE does not significantly alter sleep behaviors in participants with obesity. However, longer sleep duration at follow-up was associated with lower BMI, better insulin sensitivity, and greater improvement in insulin sensitivity, indicating that sleep may be an important variable to consider in dietary interventions. Future research examining behavioral sleep strategies in combination with TRE is needed to evaluate whether improved sleep leads to better weight loss and glycemic outcomes for individuals with obesity. Support This work was support by the Healthy Foods Healthy Lives program (17SFR-2YR50LC to LC) and the National Institutes of Health (NIH National Center for Advancing Translational Sciences, UL1TR002494).

ObjectiveThis study aimed to assess the effects of 9‐hour time‐restricted feeding (TRF), early (TRFe) or delayed (TRFd), on glucose tolerance in men at risk for type 2 diabetes.MethodsFifteen men (age 55 ± 3 years, BMI 33.9 ± 0.8 kg/m2) wore a continuous glucose monitor for 7 days of baseline assessment and during two 7‐day TRF conditions. Participants were randomized to TRFe (8 am to 5 pm) or TRFd (12 pm to 9 pm), separated by a 2‐week washout phase. Glucose, insulin, triglycerides, nonesterified fatty acids, and gastrointestinal hormone incremental areas under the curve were calculated following a standard meal on days 0 and 7 at 8 am (TRFe) or 12 pm (TRFd).ResultsTRF improved glucose tolerance as assessed by a reduction in glucose incremental area under the curve (P = 0.001) and fasting triglycerides (P = 0.003) on day 7 versus day 0. However, there were no mealtime by TRF interactions in any of the variables examined. There was also no effect of TRF on fasting and postprandial insulin, nonesterified fatty acids, or gastrointestinal hormones. Mean fasting glucose by continuous glucose monitor was lower in TRFe (P = 0.02) but not TRFd (P = 0.17) versus baseline, but there was no difference between TRF conditions.ConclusionsWhile only TRFe lowered mean fasting glucose, TRF improved glycemic responses to a test meal in men at risk for type 2 diabetes regardless of the clock time that TRF was initiated.

In animal models, time-restricted feeding (TRF) can prevent and reverse aspects of metabolic diseases. Time-restricted eating (TRE) in human pilot studies reduces the risks of metabolic diseases in otherwise healthy individuals. However, patients with diagnosed metabolic syndrome often undergo pharmacotherapy, and it has never been tested whether TRE can act synergistically with pharmacotherapy in animal models or humans. In a single-arm, paired-sample trial, 19 participants with metabolic syndrome and a baseline mean daily eating window of >= 14 h, the majority of whom were on a statin and/or antihypertensive therapy, underwent 10 h of TRE (all dietary intake within a consistent self-selected 10 h window) for 12 weeks. We found this TRE intervention improves cardiometabolic health for patients with metabolic syndrome receiving standard medical care including high rates of statin and anti-hypertensive use. TRE is a potentially powerful lifestyle intervention that can be added to standard medical practice to treat metabolic syndrome.