Sleep and quiet wakefulness signify an idling brain hub for creative insights.

Long-term potentiation of synaptic strength is a fundamental aspect of learning and memory. Memories are believed to be stored within specific populations of neurons known as engram cells, which are subsequently reactivated during sleep, facilitating the consolidation of stored information. However, sleep and offline reactivations are associated not only with past experiences but also with anticipation of future events. During periods of offline reactivation, which occur during sleep and quiet wakefulness, the brain exhibits a capability to form novel connections. This process links various past experiences, often leading to the emergence of qualitatively new information that was not initially available. Brain activity during sleep and quiet wakefulness is referred to as the 'idling brain'. Idling brain activity is believed to play a pivotal role in abstracting essential information, comprehending underlying rules, generating creative ideas and fostering insightful thoughts. In this review, we will explore the current state of research and future directions in understanding how sleep and idling brain activity are interconnected with various cognitive functions, especially creative insights. These insights have profound implications for our daily lives, impacting our ability to process information, make decisions and navigate complex situations effectively. This article is part of a discussion meeting issue 'Long-term potentiation: 50 years on'.

Memory reactivations during sleep.

Neuronal activities that occur during awake periods are often reactivated again during sleep, to consolidate recently encoded memories, a process known as consolidation. In recent years, advanced tools, specially optical techniques and in-vivo live Ca2+ imaging, have revealed a deeper understanding to the offline periods' neuronal activities and their correspondence to later awake behavioral outputs. Recently, there is a growing consensus that sleep is more of an active process. Sleep has been associated with various functions, memory updating, future imaginations of possible familiar scenarios, decision making and planning by replaying past memories. Also, boosting insightful thoughts, creative thinking and problem solving by forming new associations and connections that were not present in awake states. Sleep activities have been directly associated with many "EUREKA" or "AHA" moments. Here, we describe recent views on memory reactivations during sleep and their implications on learning and memory.

Selective engram coreactivation in idling brain inspires implicit learning.

Passive priming of prior knowledge to assimilate ongoing experiences underlies advanced cognitive processing. However, the necessary neural dynamics of memory assimilation remains elusive. Uninstructed brain could also show boosted creativity, particularly after idling states, yet it remains unclear whether the idling brain can spontaneously spark relevant knowledge assimilations. We established a paradigm that links/separates context-dependent memories according to geometrical similarities. Mice exploring one of four contexts 1 d before undergoing contextual fear conditioning in a square context showed a gradual fear transfer to preexposed geometrically relevant contexts the next day, but not after 15 min. Anterior cingulate cortex neurons representing relevant, rather than distinct, memories were significantly coreactivated during postconditioning sleep only, before their selective integration the next day during testing. Disrupting sleep coreactivations prevented assimilation while preserving recent memory consolidation. Thus, assimilating pertinent memories during sleep through coreactivation of their respective engrams represents the neural underpinnings of sleep-triggered implicit cortical learning.

The Effect of the Back-Pressure Changes in an Exhaust System on Vibration When Attaching a Variable Device during Idling.

The vibration of the ignition frequency component of the engine during idling causes driver discomfort. To minimize this, an optimal exhaust system with a variable device that can exert optimal pressure is required. In this study, the geometry of the variable device was designed in orifice and cylinder types. Next, the designed variable devices were implemented in a conventional exhaust system with an X chamber. A comparative analysis was conducted to propose an optimal geometry through back-pressure and vibration measurements. During the experiment, the orifice geometry exhibited higher back pressure than the conventional geometry and a large difference in back pressure before and at the exhaust gas merging position. Furthermore, the orifice geometry showed a 2.56% increase in the vibration of the 1X component in the Y-axis direction. By contrast, the cylinder geometry exhibited slightly higher back pressure than the conventional geometry and the smallest difference in back pressure before and at the exhaust gas merging position. The cylinder geometry showed a 2.45% reduction in the vibration of the 1X component in the Y-axis direction.

The Birth of the Mammalian Sleep.

Mammals evolved from small-sized reptiles that developed endothermic metabolism. This allowed filling the nocturnal niche. They traded-off visual acuity for sensitivity but became defenseless against the dangerous daylight. To avoid such danger, they rested with closed eyes in lightproof burrows during light-time. This was the birth of the mammalian sleep, the main finding of this report. Improved audition and olfaction counterweighed the visual impairments and facilitated the cortical development. This process is called "The Nocturnal Evolutionary Bottleneck". Pre-mammals were nocturnal until the Cretacic-Paleogene extinction of dinosaurs. Some early mammals returned to diurnal activity, and this allowed the high variability in sleeping patterns observed today. The traits of Waking Idleness are almost identical to those of behavioral sleep, including homeostatic regulation. This is another important finding of this report. In summary, behavioral sleep seems to be an upgrade of Waking Idleness Indeed, the trait that never fails to show is quiescence. We conclude that the main function of sleep consists in guaranteeing it during a part of the daily cycle.

Rapid start-up strategy of partial denitrification and microbially driven mechanism of nitrite accumulation mediated by dissolved organic matter.

The rapid start-up of Partial denitrification (PD; nitrate to nitrite) was investigated based on the analysis of microbially driven mechanism of nitrite accumulation mediated by Dissolved organic matter (DOM) in this study. The nitrate to Nitrite transformation ratio (NTR) > 90% and effluent nitrate < 5 mg/L were achieved in 17 days by feeding with lower nitrate of ~ 35 mg/L and removing the idling period. And the enhanced nitrite accumulation when applying the above strategy is related to the decreased utilization of the aliphatic DOM during nitrite reduction process. Additionally, the rapid enriched Thauera and OLB13 (37.21%) and inhibited norank_f__Blastocatellaceae (2.86%), and the increased disparity (2.0-fold) between the genes involved in nitrite generation (e.g., narH) and for nitrite reduction (e.g., nirK) jointly contributed to PD start-up. While the genes (e.g., DLD) related to producing electrons from aliphatic DOM also up-regulated by 0.1-fold, which led to the increased nitrate removal and NTR.

Different characteristics of individual particles from light-duty diesel vehicle at the launching and idling state by AAC-SPAMS.

The rapid development of cities and economic prosperity greatly motivates the growth of vehicular exhaust particles, especially the diesel-exhausted particles from the large fleet of passenger and freight, which present profound implications on climate, air quality, and biological health (e.g., pulmonary, autoimmune and cardiovascular diseases). As important physiochemical properties of atmospheric aerosols, however, the mixing state and effective density of individual particles emitted from diesel-powered vehicles under different driving conditions and their environmental implications remain uncertain. Here, a single-particle aerosol mass spectrometer (SPAMS) was used to investigate the chemical composition and vacuum aerodynamic diameter (Dva), along with the aerodynamic diameter (Da) from an aerodynamic aerosol classifier (AAC), to determine the effective density of primary particles emitted from a light- duty diesel vehicle (LDDV) under the launching and idling engine states. Interestingly, the particle types and effective density appear to vary significantly with the engine status. A single particle type of Ca-rich particles, named Na-Ca-PAH, was predominant in the idling state, whose chemical components may be affected by the lubricants and incomplete combustion, contributing to a higher effective density (0.66 ± 0.21 g cm-3). In contrast, launching particles exhibited a lower effective density (0.34 ± 0.17 g cm-3) because of the substantial elemental carbon (EC). In addition, the effective density depends not only on the particle size but also on the chemical components with various abundances. EC and Ca play opposite roles in the effective density of LDDV emissions. Notably, a higher proportion of polycyclic aromatic hydrocarbons (PAHs) was observed in the idling particles, contributing to 78 ± 1.2%. Given the high contribution to these PAH-containing particles in the idling state, indispensable precautions should be taken at bus stops or waiting for pedestrians. This study provides more comprehensive insights into the initial characteristics of LDDV particles due to the launching and idling states, which is beneficial for improving the model results of source apportionment and understanding its environmental behavior regarding human health.

Reducing car idling at primary schools: An intervention study of parent behaviour change in Perth, Western Australia.

ISSUED ADDRESSED: There is increasing evidence that exposure to traffic-related air pollution is related to childhood respiratory symptoms. This study demonstrated the effectiveness of an anti-idling behavioural intervention targeting parents at primary schools. METHODS: Based on two focus group discussions with parents, a low-intensity 4-week anti-idling intervention was developed, comprising onsite signage, four newsletters, and two fact sheets. Exposure to selected air pollutants was assessed during pick-up and drop-off times pre- and postintervention at 12 randomly selected independent schools (10 intervention and 2 control) across the Perth metropolitan area. RESULTS: The study results showed that a low-intensity behavioural intervention can be an effective strategy to affect parents' attitude towards vehicle idling. This was demonstrated by the reduced number of idling vehicles observed in 8 of the 10 intervention schools and decreased overall particulate matter concentration after the anti-idling intervention. CONCLUSION: Anti-idling education can be effective in promoting clean travel behaviours and has potential health benefits for school children. SO WHAT?: This intervention study provides insights on the significant effect of anti-idling education on parents' behaviour towards air quality and children's health. These promising findings warrant further rigorous actions on anti-idling education and enforcement.

Photo-Protective Mechanisms and the Role of Poly (ADP-Ribose) Polymerase Activity in a Facultative CAM Plant Exposed to Long-Term Water Deprivation.

The Crassulacean acid metabolism (CAM) pathway helps plants to alleviate the oxidative stress under drought, but the shift to CAM-idling may expose plants to the overproduction of reactive oxygen species causing cell damages. The facultative CAM species Portulacaria afra L., was subjected to long-term water deprivation to assess the photo-protective strategies and the poly (ADP-ribose) polymerase (PARP) activity during water stress and plant capability to recover from the stress. Measurements of titratable acidity, chlorophyll fluorescence emission, and antioxidant activity were performed during the stress and rewatering. Under water deprivation, plants shifted from C3 to CAM metabolism, reaching the CAM-idling status at the end of the stress period. The daily variation of the titratable acidity and PARP activity increased at the beginning of stress and declined with stress progression, reaching the lowest value at the end of stress treatment. H2O2 content, superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities increased with the severity of water stress. The photochemical processes remained high during the entire stress period indicating the presence of alternative sinks to CO2 fixation. The elevated activity of catalase under severe water stress suggests the occurrence of photorespiration in sustaining the photosynthetic electron transport under CAM-idling condition. The overall data indicate that scavenger enzymes, photorespiration and PARP activity modulation contribute to the strong resistance of P. afra to severe water stress, preserving the functioning of photosynthetic apparatus and ensuring plant recovery with rewatering.

Drug-Tolerant Idling Melanoma Cells Exhibit Theory-Predicted Metabolic Low-Low Phenotype.

Cancer cells adjust their metabolic profiles to evade treatment. Metabolic adaptation is complex and hence better understood by an integrated theoretical-experimental approach. Using a minimal kinetic model, we predicted a previously undescribed Low/Low (L/L) phenotype, characterized by low oxidative phosphorylation (OXPHOS) and low glycolysis. Here, we report that L/L metabolism is observed in BRAF-mutated melanoma cells that enter a drug-tolerant "idling state" upon long-term MAPK inhibition (MAPKi). Consistently, using publicly available RNA-sequencing data of both cell lines and patient samples, we show that melanoma cells decrease their glycolysis and/or OXPHOS activity upon MAPKi and converge toward the L/L phenotype. L/L metabolism is unfavorable for tumor growth, yet supports successful cell division at ~50% rate. Thus, L/L drug-tolerant idling cells are a reservoir for accumulating mutations responsible for relapse, and it should be considered as a target subpopulation for improving MAPKi outcomes in melanoma treatment.

Metabolic Modeling of the C3-CAM Continuum Revealed the Establishment of a Starch/Sugar-Malate Cycle in CAM Evolution.

The evolution of Crassulacean acid metabolism (CAM) is thought to be along a C3-CAM continuum including multiple variations of CAM such as CAM cycling and CAM idling. Here, we applied large-scale constraint-based modeling to investigate the metabolism and energetics of plants operating in C3, CAM, CAM cycling, and CAM idling. Our modeling results suggested that CAM cycling and CAM idling could be potential evolutionary intermediates in CAM evolution by establishing a starch/sugar-malate cycle. Our model analysis showed that by varying CO2 exchange during the light period, as a proxy of stomatal conductance, there exists a C3-CAM continuum with gradual metabolic changes, supporting the notion that evolution of CAM from C3 could occur solely through incremental changes in metabolic fluxes. Along the C3-CAM continuum, our model predicted changes in metabolic fluxes not only through the starch/sugar-malate cycle that is involved in CAM photosynthetic CO2 fixation but also other metabolic processes including the mitochondrial electron transport chain and the tricarboxylate acid cycle at night. These predictions could guide engineering efforts in introducing CAM into C3 crops for improved water use efficiency.

Primary emissions and secondary organic aerosol formation from in-use diesel vehicle exhaust: Comparison between idling and cruise mode.

Diesel vehicle exhaust is an important source of carbonaceous aerosols, especially in developing countries, like China. Driving condition impacts diesel vehicle emissions, yet its influence needs further understanding especially on secondary organic aerosol (SOA) formation. In this study tailpipe exhaust from an in-use light duty diesel vehicle at idling and driving speeds of 20 and 40 km h-1 was introduced respectively into a 30 m-3 indoor smog chamber to investigate primary emissions and SOA formation during photo-oxidation. The emission factors of SO2 at 20 and 40 km h-1 were higher than those at idling, whereas the emission factors of aromatic hydrocarbons (AHs), polycyclic aromatic hydrocarbons (PAHs) and oxygenated volatile organic compounds (OVOCs) decreased when driving speeds increased. The emission factors of black carbon (BC) and primary organic aerosol (POA) at idling were comparable to those at 20 and 40 km h-1. The SOA production factors were 0.41 ±â€¯0.09 g kg-fuel-1 at idling, approximately 2.5 times as high as those at 20 km h-1 (0.16 ±â€¯0.09 g kg-fuel-1) or 40 km h-1 (0.17 ±â€¯0.09 g kg-fuel-1). Total carbonaceous aerosols, including BC, POA and SOA, from diesel vehicles at 20 and 40 km h-1 were 60-75% of those at idling, due largely to a reduction in SOA production. Measured AHs and PAHs altogether were estimated to explain <10% of SOA production, and eight major OVOCs could contribute 8.4-23% of SOA production. A preliminary comparison was further made for the same diesel vehicle at idling using diesel oils upgraded from China 3 to China 5 standard. The emission factors of total particle numbers decreased by 38% owing to less nuclei mode particles, which was probably caused by the reducing fuel sulfur content; the emission factors of BC were almost unchanged, the POA emission factors and SOA production factors however decreased by 72% and 37%.

DNA damage tolerance pathway involving DNA polymerase ι and the tumor suppressor p53 regulates DNA replication fork progression.

DNA damage tolerance facilitates the progression of replication forks that have encountered obstacles on the template strands. It involves either translesion DNA synthesis initiated by proliferating cell nuclear antigen monoubiquitination or less well-characterized fork reversal and template switch mechanisms. Herein, we characterize a novel tolerance pathway requiring the tumor suppressor p53, the translesion polymerase ι (POLι), the ubiquitin ligase Rad5-related helicase-like transcription factor (HLTF), and the SWI/SNF catalytic subunit (SNF2) translocase zinc finger ran-binding domain containing 3 (ZRANB3). This novel p53 activity is lost in the exonuclease-deficient but transcriptionally active p53(H115N) mutant. Wild-type p53, but not p53(H115N), associates with POLι in vivo. Strikingly, the concerted action of p53 and POLι decelerates nascent DNA elongation and promotes HLTF/ZRANB3-dependent recombination during unperturbed DNA replication. Particularly after cross-linker-induced replication stress, p53 and POLι also act together to promote meiotic recombination enzyme 11 (MRE11)-dependent accumulation of (phospho-)replication protein A (RPA)-coated ssDNA. These results implicate a direct role of p53 in the processing of replication forks encountering obstacles on the template strand. Our findings define an unprecedented function of p53 and POLι in the DNA damage response to endogenous or exogenous replication stress.

Comportamento ingestivo e digestibilidade de nutrientes em vacas submetidas a diferentes níveis de concentrado / Ingestive behavior and nutrient digestibility in cows fed different levels of concentrate

Avaliou-se a influência do teor de concentrado na dieta sobre o comportamento ingestivo, o consumo e a digestibilidade aparente de nutrientes em bovinos. Foram utilizadas quatro vacas mestiças, com média de peso de 442,15kg, distribuídas em quadrado latino 4x4, durante quatro períodos de 14 dias, sendo 11 de adaptação e três para coleta de amostras, elaboradas por animal e por período. O comportamento foi avaliado pela observação dos animais a cada 15 minutos por 24 horas, determinando-se tempo de alimentação, ruminação, ócio e ingestão de água. Utilizou-se silagem de milho como volumoso e concentrado à base de milho, sorgo, farelo de soja, casca de soja, suplemento mineral, ureia e gordura protegida, em dietas com 13 por cento de proteína bruta. As proporções de concentrado foram de 30, 40, 50 e 60 por cento, na matéria seca. As atividades de consumo e ruminação diminuíram linearmente em função do teor de concentrado, e o tempo de ócio aumentou. Houve efeito linear da porcentagem de concentrado para eficiência do consumo e de ruminação, bem como consumo dos nutrientes da dieta, com exceção da fibra em detergente neutro. O aumento do teor de concentrado diminuiu o tempo de apreensão e ingestão e de ruminação, e não alterou a digestibilidade dos nutrientes da dieta.

The influence of concentrate levels in rations on ingestion behavior, nutrient intake, and digestibility was determined in cattle. Four 442.15kg BW crossbred cows were distributed in a 4x4 Latin square, into four periods of 14 days, 11 days for adaptation and three days for sample collections per animal and per period. Behavior was determined by observing each animal every 15 minutes for 24 hours, recording feeding, rumination, idling, and water uptake time. The roughage was whole-plant corn silage and the concentrate was composed of corn, sorghum, soybean meal and hulls, minerals, urea, and protected fat, in rations with 13 percent crude protein. The concentrate levels were 30, 40, 50, and 60 percent in dry matter. Intake and rumination activities decreased linearly with the concentrate level, and consequently, there was increasing idling time. A linear effect was observed for concentrate levels on intake and rumination efficiencies, as well as for intake of the dietary nutrients, but not for neutral detergent fiber intake. Increases in the concentrate level decreased feeding and rumination times, but did not alter nutrient digestibility in the diet.

Use of a remote car starter in relation to smog and climate change perceptions: a population survey in Québec (Canada).

Remote car starters encourage motorists to warm up their vehicles by idling the motor--thus increasing atmospheric pollutants, including several greenhouse gas (GHG) with impacts on public health. This study about climate change (CC) adaptation and mitigation actions examined perceptions on air pollution and climate change and individual characteristics associated with the use of a remote car starter. A telephone survey (n = 2,570; response rate: 70%) of adults living in Québec (Canada) measured the respondents' beliefs and current behaviours regarding CC. Approximately 32.9% (daily car users) and 27.4% (occasional users) reported using a remote car starter during winter. The odds of the use of a remote car starter was higher in the less densely populated central (OR: 1.5) and peripheral regions (OR: 2.7) compared to the urban centers (ex. Montreal). The odds was also higher in population with a mother tongue other than English or French (OR: 2.6) and francophones than anglophones (OR: 2.1), women than men (OR: 1.5), daily drivers than occasional ones (OR: 1.2), and respondents who at least sometimes consulted temperature/humidity reports than those who consulted them less often (OR: 1.5). In multivariate analysis, the perception of living in a region susceptible to winter smog, being aware of smog warnings, or the belief in the human contribution to CC did not significantly influence the use of a remote car starter. The use of remote car starters encourages idling which produces increased atmospheric pollution and GHG production and it should be more efficiently and vigorously managed by various activities. A five-minute daily reduction in idling is equivalent to reducing the total car emissions by 1.8%. This would constitute a "no-regrets" approach to CC as it can simultaneously reduce GHG, air pollution and their health impacts.