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Residential space-conditioning-based demand flexibility (DF) has become an increasingly sought-after method for demand-side load management to enhance grid reliability and facilitate integration of renewable energy generation. However, predicting the effectiveness and flexibility of residential DF resources is challenging. Current estimates show that only 50% of projected savings from DF resources are actualized. Currently, there is a very limited understanding of how thermal comfort during space-conditioning-based DF events in real-world settings impacts household energy use behaviors and, consequently, the success of DF programs in achieving targeted savings. This paper proposes a method to comprehensively assess the thermal comfort implications of DF strategies and presents results of their impacts on DF event participation decisions and demand savings. The study's key findings are: 1) DF event setpoint offsets that maintain indoor operative temperatures between 18 to 22°C (65 to 71°F) may be preferred in Cordova, Alaska; 2) Household-level thermal comfort is more sensitive to the duration of the DF event than to the degree of temperature offset from baseline conditions; 3) The delayed impact of changes in indoor operative temperature in response to setpoint offsets, both during and after a DF event, influences occupants’ thermal comfort perceptions and willingness to persistently participate in events. The findings from application of the proposed method can help inform future larger-scale occupant-centric DF programs as it can capture information not readily available. Thus, it can supplement these sources and help develop occupant-centric DF strategies, enabling more accurate predictions of participation rates and savings estimates for space-conditioning-based DF programs.

The operational carbon emissions intensity of the electricity used in a building is commonly treated as a fixed value but grid carbon emissions factors have temporal and geographical variations, which makes building operating emissions dependent on when and where electricity is used. Grid electricity carbon characteristics can be quantified by either average or marginal emission rates, leading to an increasing debate about which metric provides more accurate results for determining the effect of various decarbonization strategies. We advocate for the use of the marginal operating emissions rate (MOER) to evaluate the impacts of demand-side management because it considers the generating plants' dispatch order and is able to reflect the change in emissions induced by demand management. In this study, we examined the benefits of emission-based load-shifting strategies by first analyzing the annual temporal variations of the Northern California grid region and developed a virtual chiller load shift strategy similar to demand response but interacting with the grid MOER signal. We then assessed its effect on the case study building by calculating the avoided emissions on a seasonal and annual basis through a numerical simulation. As a result, we found that for the Northern California region, shifting load is most effective during the spring season with 18% avoided carbon emissions when the grid has more renewable supply. However, the simulated annual result shows 2% avoided carbon emissions indicating the seasonal characteristics of the proposed strategy and the limitation of considering load shift strategy as the single solution to decarbonize.

Extreme heat causes more weather-related deaths in the United States than any other natural hazard, and these events are projected to increase in frequency, intensity, and duration. As a result, it is critical to ensure safe thermal conditions in homes while minimizing excessive cooling energy use. In California, where the median age of homes is 45 years and nearly 40% lack mechanical cooling, this deficiency undermines one of the most essential goals of housing: to shelter people from outdoor weather of a warming planet. We aim to quantify the overheating risk in the housing sector to support the development of public policies related to maximum safe indoor thermal limits and building energy use. Using the ResStock modeling framework, we created over 52,000 building models to represent California's residential housing stock and assessed overheating risks by simulating indoor temperatures and analyzing the energy impacts of adding cooling systems.Our findings reveal significant regional disparities. Southern counties face the highest overheating risk, while coastal areas are less vulnerable due to oceanic temperatures. Inland counties, such as the Sierra Nevada region, are also less affected due to higher altitudes. Approximately 1.6 million homes will require retrofitting with cooling systems, which could increase peak electricity demand by 2%. Our sensitivity analysis showed that increasing the threshold temperature reduces the number of homes subject to overheating risk. These results significantly impact the electricity grid, emphasizing the need to consider passive cooling options like shading and cool roofs or energy-efficient cooling options like fans and evaporative coolers.

Mitochondria are crucial for cellular metabolism and signalling. Mitochondrial activity is modulated by mitochondrial fission and fusion, which are required to properly balance metabolic functions, transfer material between mitochondria, and remove defective mitochondria. Mitochondrial fission occurs at mitochondria-endoplasmic reticulum (ER) contact sites, and requires the formation of actin filaments that drive mitochondrial constriction and the recruitment of the fission protein DRP1. The role of actin in mitochondrial fusion remains entirely unexplored. Here we show that preventing actin polymerisation on either mitochondria or the ER disrupts both fission and fusion. We show that fusion but not fission is dependent on Arp2/3, whereas both fission and fusion require INF2 formin-dependent actin polymerization. We also show that mitochondria-associated actin marks fusion sites prior to the fusion protein MFN2. Together, our work introduces a method for perturbing organelle-associated actin and demonstrates a previously unknown role for actin in mitochondrial fusion.

Amyotrophic lateral sclerosis (ALS) is linked to the reduction of certain nucleoporins in neurons. Increased nuclear localization of charged multivesicular body protein 7 (CHMP7), a protein involved in nuclear pore surveillance, has been identified as a key factor damaging nuclear pores and disrupting transport. Using CRISPR-based microRaft, followed by gRNA identification (CRaft-ID), we discovered 55 RNA-binding proteins (RBPs) that influence CHMP7 localization, including SmD1, a survival of motor neuron (SMN) complex component. Immunoprecipitation-mass spectrometry (IP-MS) and enhanced crosslinking and immunoprecipitation (CLIP) analyses revealed CHMP7's interactions with SmD1, small nuclear RNAs, and splicing factor mRNAs in motor neurons (MNs). ALS induced pluripotent stem cell (iPSC)-MNs show reduced SmD1 expression, and inhibiting SmD1/SMN complex increased CHMP7 nuclear localization. Crucially, overexpressing SmD1 in ALS iPSC-MNs restored CHMP7's cytoplasmic localization and corrected STMN2 splicing. Our findings suggest that early ALS pathogenesis is driven by SMN complex dysregulation.

The need for cooling in buildings is mainly handled using systems based on the refrigeration cycle, often an energy- and cost-intensive process. High thermal mass radiant systems (HTMR) enable the use of warmer than typical chilled water temperatures to provide cooling. In favorable weather conditions, the cooled water can be produced through low-energy and low-cost cooling devices. In this two-phased study, we first determined the warmest supply water temperature (SWT) needed in HTMR that maintains thermally comfortable conditions on the cooling design day. Then, we investigated the potential of replacing the refrigeration cycle with evaporative cooling devices in the primary cooling system. We performed a quasi-random sampling of building and HTMR system design parameters representing typical building characteristics and design cooling loads for lighting, people, and plug loads to create 360,900 single zone EnergyPlus models. We iteratively simulated the models on the climate zones’ cooling design day to find the warmest SWT that did not exceed a maximum zone operative temperature of 26 °C. The test cases include simulations using 14 ASHRAE and 16 California climate zones. The results show that HTMR can use SWT of 12.3, 18.2, and 21.1 °C for the 25th, 50th, and 75th percentile, respectively, of test cases, indicating that overall cooling energy and costs can be reduced in all US climates through high-temperature cooling. In addition, high-temperature cooling allows at least 40% of waterside economizer operation during the cooling season for 21 out of 30 climate zones with reasonably performing evaporative cooling devices.

Heat is a leading weather-related cause of death worldwide and heat waves are increasing globally in terms of frequency, duration, and intensity. Global heat-related deaths could quadruple by midcentury. As with many environmental hazards, numerous factors impact how heat might affect any given person and there are significant gaps in our understanding related to indoor heat and its effect on health. Despite growing interest in establishing standards and guidelines, there is currently no clear consensus on a safe maximum upper limit for indoor temperature. There is conclusive evidence of links between high outdoor temperatures and human health yet research on this correlation does not typically explicitly consider indoor heat exposure. Considerably more research has been completed on healthy, active individuals than for more heat-susceptible populations and the impacts of moderate heat stress on the health of large populations are not well understood. We conducted a literature review on the impact of indoor thermal conditions on health, recognizing that air temperature alone cannot describe thermal exposure. We introduce the concept of a standardized maximum safe indoor temperature, defined for still air conditions, 50% relative humidity and mean radiant temperature equal to air temperature. Equivalent temperatures with respect to the thermal load on the body can then be calculated for various air velocities, humidities or mean radiant temperatures using the standard effective temperature (SET) model. For U.S. policymakers, we propose adopting a standardized maximum safe indoor temperature of 28 °C. We recognize that the adoption of standardized maximum safe indoor temperatures may vary around the world, but the framework we propose to adjust the standardized upper limit for humidity, air motion, and radiant temperature could be used globally. We also identify important knowledge gaps to guide future research on the relationships between heat and health that could support informed cost-benefit analyses.

In an experimental study set in Singapore's tropical climate, we evaluated the thermal environmental performance, energy consumption, and thermal comfort of air and radiant cooling systems, operating at an operative and air temperature of 26 °C. 78 participants across five groups answered thermal comfort surveys in a crossover study design. Environmental performance metrics indicated that both systems produced similar conditions, with a noticeable difference in air velocity. The mean radiant temperature to air temperature difference was less than 0.5 °C in both systems. The radiant system exhibited a 33 % higher heat flux extraction than the air system and required less electrical power for the transportation of the cooling medium and ventilation air. Overall, the radiant system used 4 % less energy than the air system when controlled at 26 °C and 34 % when operated at 23 °C. Results show that radiant and air systems provided equal thermal comfort in cooling, with over 60 % of participants expressing satisfaction and ∼ 20 % voted neutral thermal satisfaction. ∼ 40 % of participants preferred cooler conditions, and ∼ 30 % desired increased air movement.

Proper regulation of organelle dynamics and inter-organelle contacts is critical for cellular health and function. Both the endoplasmic reticulum (ER) and actin cytoskeleton are known to regulate organelle dynamics, but how, when, and where these two subcellular components are coordinated to control organelle dynamics remains unclear. Here, we show that ER-associated actin consistently marks mitochondrial, endosomal, and lysosomal fission sites. We also show that actin polymerization by the ER-anchored isoform of the formin protein INF2 is a key regulator of the morphology and mobility of these organelles. Together, our findings establish a mechanism by which INF2-mediated polymerization of ER-associated actin at ER-organelle contacts regulates organelle dynamics.

Windows provide access to daylight and outdoor views, influencing building design. Various glazing and window shade materials are used to mitigate glare, overheating and privacy issues, and they affect view clarity. Among them, we evaluated the effect of window films, electrochromic (EC) glass, and fabric shades on view clarity. We conducted an experiment with 50 participants using visual tests adapted from clinical vision tests (visual acuity, contrast sensitivity, color sensitivity) and images displayed on a computer monitor in a controlled laboratory. Window films and EC glass tints outperformed fabric shades in visual acuity, contrast sensitivity and view satisfaction with the exception of the darkest EC tint state and dark grey VLT 3% shade for color sensitivity and view satisfaction. The EC tints pose internal reflection issues and fabric shades are preferred for visual privacy. Window films and EC glass hinder participants blue-green color discrimination while fabric shades also decrease red-yellow color discrimination. Visual acuity predicts view satisfaction and contrast sensitivity is the strongest predictor for visual privacy. Generally, higher visible light transmittance and lower solar reflectance (darker color) enhance human visual performance. The proposed workflow provides an experimental procedure, identifies the primary variables and establishes a predictive framework for assessing view clarity of fenestration.

Desk fans allow individual thermal adjustment in shared spaces which increases occupants' thermal satisfaction. When associated with the increase of room conditioning system setpoint temperature, they can also reduce energy use. In comparison to other Personal Comfort Systems (PCS), low-power desk fans can be very efficient for cooling. Nevertheless, previous studies identify some barriers to their implementation and show no clear guidelines on how to overcome them. Therefore, this study presents the results of a field implementation of desk fans in an open office in Brazil. The intervention consisted of providing one desk fan for each occupant and progressively increasing the setpoint temperature. Indoor thermal conditions were recorded simultaneously with occupants' thermal perception using sensors and surveys. Results show fans increased thermal satisfaction by 20 %. And, when fans were available, the preferred indoor air temperature increased by 1 °C. However, many constraints affect the results. Based on this experience, we propose guidelines for future implementation. We emphasize the need to understand the HVAC system, engage building operators, and apply gradual temperature modification. As occupants’ expectations had a great impact on the potential temperature extension, we suggest a way to limit temperature extension in future implementations.

International building certification systems, such as the WELL and Leadership in Energy and Environmental Design (LEED) standards, play a pivotal role in the design of healthy and sustainable buildings. While LEED adopts a holistic approach to designing healthy and sustainable buildings, the WELL standard has a strong emphasis on human health, comfort, and well-being. Although prior research has revealed inconsistent results for occupant satisfaction in office buildings with WELL certification compared to buildings without WELL certification, or are certified using another certification system (e.g., LEED), most of these comparisons tend to lack methodological rigor. This study used a statistical procedure to match and compare 1634 occupant surveys from LEED-certified buildings to 1634 surveys from WELL-certified buildings. Six important architectural and experiential parameters were matched, masking their influence on the outcome. Overall building and workspace satisfaction was high in both WELL-certified buildings (94% and 87%) and LEED-certified (73% and 71%). We found that there is a 39% higher probability of finding occupants who are more satisfied in WELL-certified buildings compared to LEED-certified buildings, indicating occupant satisfaction is higher in buildings with WELL certification. Although we were unable to pinpoint the reason for higher occupant satisfaction in WELL-certified buildings, the results consistently showed that perceived indoor environmental quality was enhanced across all parameters except for the amount of space.

Causal thinking emphasizes the understanding of asymmetric causal relationships between variables, requiring us to specify which variable is the cause (independent variable) and which is the effect (dependent variable). Reversing the causal relationship direction can lead to profoundly different assumptions and interpretations. We demonstrate this by comparing two linear regression approaches used in thermal comfort research: Approach (a), which regresses thermal sensation votes (y-axis) on indoor temperature (x-axis); Approach (b), which does the reverse, regressing indoor temperature (y-axis) on thermal sensation votes (x-axis). From a correlational perspective, they may appear interchangeable, but causal thinking reveals substantial and practical differences between them. Approach (a) represents occupants’ thermal sensations as responses to indoor temperature. In contrast, Approach (b), rooted in adaptive comfort theory, suggests that thermal sensations can trigger behavioral changes, which in turn alter indoor temperature. Using the same data, we found that two approaches lead to different neutral temperatures and comfort zones. Approach (b) leads to what we call a ‘preferred zone’, which is 10 °C narrower than the conventionally derived comfort zone using Approach (a). We hypothesize that the ‘preferred zone’ might be interpreted as thermal conditions that occupants are likely to choose when they have significant control over their personal and environmental thermal settings. This finding has important implications for occupant comfort and building energy efficiency. We highlight the importance of integrating causal thinking into correlation-based statistical methods, which have been prevalent in building science research, especially given the increasing volume of data in the built environment.

In high- and middle-income countries, there is a great reliance on heating, ventilation, and air conditioning systems (HVAC) to control the interior thermal environment. However, these systems are expensive to buy, maintain, and operate while being energy and environmentally intensive. Easily-accessible passive and low-energy strategies, such as fans and electrical heated blankets, address these challenges but their comparative effectiveness for providing comfort in sleep environments has not been studied. Using passive strategies in combination with low-energy strategies that elevate air movement like ceiling or pedestal fans enhances the cooling effect by three times compared to using fans alone. We extrapolated our experimental findings to estimate heating and cooling effects in two historical case studies: the 2015 Pakistan heat wave and the 2021 Texas power crisis. Passive and low-energy strategies reduced sleep-time heat or cold exposure by 69-91%. The low-energy strategies we tested require one to two orders of magnitude less energy than HVAC systems, and the passive strategies require no energy input. These strategies can also help reduce peak load surges and total energy demand in extreme temperature events. This reduces the need for utility load shedding, which can put individuals at risk of hazardous heat or cold exposure. Our results may serve as a starting point for evidence-based public health guidelines on how individuals can sleep better during heat waves and cold snaps without relying on HVAC.

This study aims to measure the impact of having visual connections to nature through windows on the cognitive performance of university students, as assessed by their final exam scores. To build upon prior research conducted in controlled laboratory and climate chamber settings, which may have a gap between findings and real-world contexts, demonstrating the positive effects of window views on occupants, this study addressed the limitations of lab-based experiments by conducting a field test in university lecture rooms with 121 students enrolled in STEM classes, taking their actual final exam. In the field test, we randomly assigned the students to either of two conditions: one with windows and one without, while monitoring indoor environmental factors. The results revealed no significant difference in cognitive performance—whether measured by scores or cognitive efficiency gauged by the time taken to complete the exam—between students in conditions with and without window views. Given the known small effect size of having windows on cognitive performance and the relatively small number of data points, we recognized that further iterations of the field tests are required to accumulate a more substantial dataset and draw more robust conclusions.

Climate-responsive building design holds immense potential for enhancing comfort, energy efficiency, and environmental sustainability. However, many social, cultural, and economic obstacles might prevent the wide adoption of designing climate-adapted buildings. One of these obstacles can be removed by enabling practitioners to easily access, visualize and analyze local climate data. The CBE Clima Tool (Clima) is a free and open-source web application that offers easy access to publicly available weather files and has been created for building energy simulation and design. It provides a series of interactive visualizations of the variables contained in the EnergyPlus Weather Files and several derived ones like the UTCI or the adaptive comfort indices. It is aimed at students, educators, and practitioners in the architecture and engineering fields. Since its inception, Clima’s user base has exhibited robust growth, attracting over 25,000 unique users annually from across 70 countries. Our tool is poised to revolutionize climate-adaptive building design, transcending geographical boundaries and fostering innovation in the architecture and engineering fields.

The decision-making process in real-world implementations has been affected by a growing reliance on data-driven models. Recognizing the limitations of isolated methodologies - namely, the lack of domain understanding in data-driven models, the subjective nature of empirical knowledge, and the idealized assumptions in first-principles simulations, we explore their synergetic integration. We showed the potential risk of biased results when using data-driven models without causal analysis. Through a case study on energy consumption in building design, we demonstrate how causal analysis significantly enhances the modeling process, mitigating biases and spurious correlations. We concluded that: (a) Sole data-driven models' accuracy assessment or domain knowledge screening may not rule out biased and spurious results; (b) Data-driven models' feature selection should involve careful consideration of causal relationships, especially colliders; (c) Integrating causal analysis results aid to first-principles simulation design and parameter checking to avoid cognitive biases. We advocate for the routine integration of causal inference within data-driven models in engineering practices, emphasizing its critical role in ensuring the models' reliability and real-world applicability.

OBJECTIVE: Modeling the effect of meal composition on glucose excursion would help in designing decision support systems (DSS) for type 1 diabetes (T1D) management. In fact, macronutrients differently affect post-prandial gastric retention (GR), rate of appearance (R[Formula: see text]), and insulin sensitivity (S[Formula: see text]). Such variables can be estimated, in inpatient settings, from plasma glucose (G) and insulin (I) data using the Oral glucose Minimal Model (OMM) coupled with a physiological model of glucose transit through the gastrointestinal tract (reference OMM, R-OMM). Here, we present a model able to estimate those quantities in daily-life conditions, using minimally-invasive (MI) technologies, and validate it against the R-OMM. METHODS: Forty-seven individuals with T1D (weight =78±13 kg, age =42±10 yr) underwent three 23-hour visits, during which G and I were frequently sampled while wearing continuous glucose monitoring (CGM) and insulin pump (IP). Using a Bayesian Maximum A Posteriori estimator, R-OMM was identified from plasma G and I measurements, and MI-OMM was identified from CGM and IP data. RESULTS: The MI-OMM fitted the CGM data well and provided precise parameter estimates. GR and R[Formula: see text] model parameters were not significantly different using the MI-OMM and R-OMM (p 0.05) and the correlation between the two S[Formula: see text] was satisfactory ( ρ =0.77). CONCLUSION: The MI-OMM is usable to estimate GR, R[Formula: see text], and S[Formula: see text] from data collected in real-life conditions with minimally-invasive technologies. SIGNIFICANCE: Applying MI-OMM to datasets where meal compositions are available will allow modeling the effect of each macronutrient on GR, R[Formula: see text], and S[Formula: see text]. DSS could finally exploit this information to improve diabetes management.