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Although Guangxi represents one of the distribution centres of begonias in China, the sect. Diploclinium (Wright) A. DC is not well documented herein. In this article, we illustrate a new species belonging to this section, Begoniafangchengensis Y.N.Huang, X.X. Feng & R.K.Li, which has been discovered in southern Guangxi. Begoniafangchengensis mostly resembles B.rotundilimba in elliptic leaf blade, palmate veins, dichasial cyme, three styles, axile placentation, and unequally 3-winged capsule. On the other hand, B.fangchengensis is characterized by creeping rhizome, pilose stipule, red and densely pilose petiole, pubescent leaf blade and pilose inflorescence bract, sparsely pilose ovary and the zygomorphic androecium, differing from the erect stem at anthesis, the green and densely villous petiole, the glabrous stipule, leaf blade, inflorescence bract, ovary and actinomorphic androecium in B.rotundilimba . Considering its small population size and narrow distribution, its conservation status is categorized as 'Endangered (D)' according to the IUCN Red List Categories and Criteria., Competing Interests: The authors have declared that no competing interests exist., (Ping-Ting Hu, Yu-Ni Huang, Meng-Ni Zhang, Bi-Xuan Chen, Shu-Shu Huang, Ren-Kun Li, Wen-Guang Wang, Xin-Xin Feng.)

In severely symptomatic patients with primary severe mitral regurgitation at high or prohibitive surgical risk, mitral transcatheter edge-to-edge repair is a reasonable strategy. We present a successful case of right internal jugular vein access using PASCAL mitral valve repair (Edwards Lifesciences) in a patient with prohibitive risk for surgical mitral repair., Competing Interests: Dr Whisenant has served as a consultant for Edwards Lifesciences and Abbott Vascular. Dr Hu has reported that he has no relationships relevant to the contents of this paper to disclose., (© 2024 The Authors.)

INTRODUCTION: Agricultural aircraft operations are associated with unique challenges. In particular, these include maintaining awareness of obstacles associated with flight at very low altitudes. Wire strikes are a common cause of accidents in these operations. METHODS: Focus groups were completed during the 2022 Ag Aviation Expo hosted by the National Agricultural Aviation Association with pilots who had experienced wire-strike events ( N = 22). The researchers coded the transcripts using a human factors framework. RESULTS: Notably, unplanned "trim passes" were a key stage of flight during wire-strike events. Cognitive risk factors that may have affected their performance included situation awareness, decision-making choices, and pressure to perform. Over half of subjects reported being aware of the wire before collision. Possible prevention strategies include not spraying the field due to safety risks, paying better attention to where they were in the field, and avoiding deviation from the planned route. DISCUSSION: Wire-strike events often occur due to momentary lapses in attention, even when the pilot is already aware of the wire. This study shows that targeted approaches to prevent wire strikes in agricultural aviation operations require addressing a number of cognitive risks and human factors, rather than implementing increased preflight surveillance. These results have implications for preventing future wire-strike accidents based directly on pilot perceptions, both within agricultural operations and general aviation more broadly. Baumgartner HM, DiDomenica R, Hu PT, Thomas S. Pilot perceptions of wire strikes in agricultural aviation operations . Aerosp Med Hum Perform. 2024; 95(6):305-312.

The floating catkins generated by willow and poplar trees have been criticized for spreading germ and causing fire for decades. It has been found that catkins are with a hollow tubular structure, which made us wonder if the floating catkins can adsorb atmospheric pollutions. Thus, we conducted a project in Harbin, China to investigate whether and how willow catkins could adsorb atmospheric polycyclic aromatic hydrocarbons (PAHs). The results suggest that both the catkins floating in the air and on the ground preferred to adsorb gaseous PAHs rather than particulate PAHs. Moreover, 3- and 4-ring PAHs were the dominating compositions adsorbed by catkins, which significantly increased with exposure time. The gas/catkins partition (K CG ) was defined, which explained why 3-ring PAHs are more easily adsorbed by catkins than by airborne particles when their subcooled liquid vapor pressure is high (log P L > -1.73). The removal loading of atmospheric PAHs by catkins were estimated as 1.03 kg/year in the center city of Harbin, which may well explain the phenomenon that levels of gaseous and total (particle + gas) PAHs are relatively low in the months with catkins floating reported in peer-reviewed papers., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Gas/particle (G/P) partitioning is an important influencing factor for the environmental fate of semi-volatile organic compounds (SVOCs). The G/P partitioning of polycyclic aromatic hydrocarbons (PAHs) is an integrated complex process due to its formation and growth concurrently with particles. Based on the large dataset of gaseous and particulate samples in a wide ambient temperature range of 50 °C, the simple empirical equations based on ambient temperature were established to predict the G/P partitioning quotient (K P ) of PAHs at the temperature range from 252 K to 307 K (-21 °C to 34 °C). The performance of the empirical equations was validated by comparison with the monitoring K P of PAHs worldwide. The empirical equations exhibited good performance for the prediction of K P of PAHs based on ambient temperature. Two deviations with the prediction lines of the previous G/P partitioning models from the monitoring data of K P were observed. It was found that the deviations might be attributed to some non-considered influencing factors with the previous G/P partitioning prediction models. Therefore, further research should be conducted to study the mechanism of the G/P partitioning of PAHs, and more influencing factors should be introduced into the establishment of G/P partitioning models of PAHs. In summary, the result of the present study provided a convenient method for the prediction of K P of PAHs, which should be useful for the study of environmental fate of PAHs in atmosphere., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The risk of human exposure to particulate novel brominated flame retardants (NBFRs) in the atmosphere has received increasing attention from scientists and the public, but currently, there is no reliable approach to predict the intake of these compounds on the basis of their size distribution. Here, we develop a reliable approach to predict the size-dependent inhalation intake of particulate NBFRs, based on the gas/particle (G/P) partitioning behavior of the NBFRs. We analyzed the concentrations of eight NBFRs in 363 size-segregated particulate samples and 99 paired samples of gaseous and bulk particles. Using these data, we developed an equation to predict the G/P partitioning quotients of NBFRs in particles in different size ranges ( K P i ) based on particle size. This equation was then successfully applied to predict the size-dependent inhalation intake of particulate NBFRs in combination with an inhalation exposure model. This new approach provides the first demonstration of the effects of the temperature-dependent octanol-air partitioning coefficient ( K OA ) and total suspended particle concentration (TSP) on the intake of particulate NBFRs by inhalation. In an illustrative case where TSP = 100 μg m -3 , inhalation intake of particulate NBFRs exceeded the intake of gaseous NBFRs when log K OA > 11.4.

Multimedia fugacity models have long been used to address the fate of toxic organic chemical emissions by providing a quantitative account of the sources, transport processes, and sinks. Recently, we have examined three level-III fugacity models (E4F (equilibrium six-compartment four-fugacity), S6F (steady-state six-compartment six-fugacity) and S4F (steady-state six-compartment four-fugacity) Models), in the context of their performance set against real-world data, and their practicality of application. Here, we discuss how the balance between gaseous and aerosol phases of emissions assumed for initial conditions affects the different model outcomes. Our results show that the S6F Model predictions closely match those of the S4F Model when chemical emissions are entirely in the gas-phase. As the particulate proportion of the emission increases, the S6F Model predictions diverge from those of the S4F Model and approach those of the E4F Model. Once the particulate portion reaches 100%, the S6F and E4F Models produce identical results: an internally inconsistent system where chemicals are not in a steady state between air and aerosols, and mass balance for both air and aerosols is not achieved. Thus, in terms of practicality, internal consistency, chemical mass balance and agreement with observations, the S4F Model is clearly the best choice., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

In this paper, two level III fugacity models are developed and applied using an environmental system containing six compartments, including air, aerosols, soil, water, suspended particulate matters (SPMs), and sediments, as a "unit world". The first model, assumes equilibrium between air and aerosols and between water and SPMs. These assumptions lead to a four-fugacity model. The second model removes these two assumptions leading to a six-fugacity model. The two models, compared using four PBDE congeners, BDE-28, -99, -153, and -209, with a steady flux of gaseous congeners entering the air, lead to the following conclusions. 1. When the octanol-air partition coefficient (K OA ) is less than 10 11.4 , the two models produce similar results; when K OA > 10 11.4 , and especially when K OA  > 10 12.5 , the model results diverge significantly. 2. Chemicals are in an imposed equilibrium in the four-fugacity model, but in a steady state and not necessary an equilibrium in the six-fugacity model, between air and aerosols. 3. The results from the six-fugacity model indicate an internally consistent system with chemicals in steady state in all six compartments, whereas the four-fugacity model presents an internally inconsistent system where chemicals are in equilibrium but not a steady state between air and aerosols. 4. Chemicals are mass balanced in air and aerosols predicted by the six-fugacity model but not by the four-fugacity model. If the mass balance in air and aerosols is achieved in the four-fugacity model, the condition of equilibrium between air and aerosols will be no longer valid., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The atmosphere is a significant medium for the transportation and diffusion of volatile and semi-volatile pollutants. Furthermore, the atmosphere is the primary exposure route for pollutants to enter the human body. Therefore, the study of the environmental fate of pollutants in the atmosphere is essential. In this study, 16 polycyclic aromatic hydrocarbons (PAHs) were analyzed in snow samples and air samples within 24 hours after a snowfall, and the temporal trend of PAHs in the atmosphere was comprehensively studied. The results indicated that the detection rate of the 16 PAHs in snow was 100%, and the concentration of phenanthrene (538.3 ng·L -1 ) was the highest, followed by naphthalene (509.1 ng·L -1 ) and fluoranthene (429.9 ng·L -1 ), indicating that snowfall can remove PAHs from the atmosphere. After the snowfall, a falling-rising-falling temporal trend of the concentrations of PAHs in the atmosphere was observed. Higher concentrations appeared during rush hour, with the largest automobile exhaust emissions, while lower concentrations appeared during periods with the lowest human activity. The results indicated that the atmospheric concentrations of PAHs were predominantly influenced by human activities. Within 24 hours after snowfall, the ratio of PAHs between the gas phase and particle phase, which depends primarily on the physical and chemical properties of PAHs, had not changed substantially. The diagnostic ratios indicated that within 24 hours after snowfall, the PAHs in the atmosphere originated mostly from the emissions of solid fuel and liquid fuel combustion.

Gas/particle (G/P) partition quotients of semi-volatile organic compounds (SVOCs) for bulk air have been widely discussed in experimental and theoretical contexts, but research on size-resolved G/P partition quotients (K Pi ) are scarce and limited in scope. To investigate G/P partition behavior of polybrominated diphenyl ethers (PBDEs) for size-segregated particles in the atmosphere, 396 individual size-segregated particulate samples (36 batches × 11 size-ranges), and 108 pairs of concurrent gaseous and bulk particulate samples were collected in Harbin, China. A steady-state equation based on bulk particles is derived to determine G/P partition quotients of PBDEs for size-segregated particles, which depends on the organic matter contents of size-segregated particles (f OMi ). This equation can well predict K Pi with knowledge of bulk partition quotient (K PS ), ambient temperature, and f OMi , the results of which match well with monitoring data in Harbin and other published data collected in Shanghai and Guangzhou of China and Thessaloniki of Greece, and remedies a defect of over-estimate K Pi for high-brominated PBDEs by the previous equation. In particular, the new equation contributes to obtaining the PBDEs concentrations in all atmospheric phase from partial phase, then provides a credible path to evaluate healthy exposure dose from the airborne PBDEs, by co-utilization with exposure models., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Virtual visits (VVs) are a modality for delivering health care services remotely through videoconferencing tools. Data about patient and physician experience in using VVs are limited., Objective: The purpose of this study was to assess patient and physician experience with the use of VVs in cardiac electrophysiology., Methods: We performed a prospective survey of cardiac electrophysiology patients and physicians who participated in an outpatient VV from December 2018 to July 2019., Results: One-hundred consecutive VVs were included. Sixty-four patients elected to complete a survey. Patients rated their experience as either excellent/very good in scheduling a VV (87%), seeing their physician of choice (100%), transmitting arrhythmia data (88%), rating their physician's ability to communicate (98%), asking all questions (98%), rating the level of care received (98%), paying for the cost of a VV (67%), and rating their overall level of satisfaction (98%). Thirty-eight of 64 patients (59.4%) preferred a VV for their next visit, 12 of 64 (18.8%) preferred an in-office visit, 13 of 64 (20.3%) responded that their decision for a virtual or office visit depended on indication, and 1 of 64 (1.6%) had no preference. A total of 14 cardiac electrophysiologists participated in 100 VVs. Nine visits were not included due to technical difficulty. Physician responses to survey questions were rated as excellent/very good in the ability to communicate (92%), accessing monitoring data (95%), and overall level of satisfaction (98%)., Conclusion: In our small study population, most patients and physicians prefer VVs. Convenience, cost, and reason for follow-up were important determinants that affected both patient and physician preference., (Copyright © 2020 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Gas/particle (G/P) partitioning of semi-volatile organic compounds (SVOCs) such as polybrominated diphenyl ethers (PBDEs), is an important atmospheric process due to its significance in governing atmospheric fate, wet/dry deposition, and long-range atmospheric transport. In this article, eight models published to predict the G/P partitioning of PBDEs are reviewed. These eight models are used to calculate the G/P partitioning quotient and particulate phase fraction of selected PBDE congeners. A comparison of the predicted results from the eight models with monitoring data published by several research groups worldwide leads to the following conclusions: 1) when the values of the logarithm of the octanol-air partition coefficient (logK OA ) fall below 11.4 (the first threshold value, logK OA1 ), all 8 models perform well in predicting the G/P partitioning of PBDEs in the atmosphere, and 2) when logK OA is >11.4, and especially above 12.5 (the second threshold value, logK OA2 ), the Li-Ma-Yang model, a steady-state model developed based on wet and dry deposition of the particles (Li et al., Atmos. Chem. Phys. 2015; 15:1669-1681), shows the best performance with highest conformity to the measurements for selected PBDEs (94.4 ± 1.6% data points within ±1 log unit). Overall, the Li-Ma-Yang model appears to capture the most important factors that affect the partitioning of PBDEs between gaseous and particular phases in the atmosphere., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The gas/particle (G/P) partitioning (K P ) behavior is an important factor for the environmental fate of PAHs in atmosphere. Based on large database of log K P , equilibrium-state and steady-state models were applied for the comprehensive study with the G/P partitioning of PAHs, including the Harner-Bidleman (H-B) model, the Dachs-Eisenreich (D-E) model, and the Li-Ma-Yang (L-M-Y) model. For different sites, the trend of regression between log K P and log K OA was same, however, the slopes and intercepts were different. No obvious difference was observed between northern Chinese cities and southern Chinese cities. For congeners and aromatic rings of PAHs, the difference was much more obvious for the regressions, slopes and intercepts. The prediction of the D-E model and the H-B model matched well for the regression of the 4-rings and 5-rings PAHs, with >80% of monitoring data points in the range of ±1 log unit. The L-M-Y model only predicted well with the measurement for 4-rings PAHs with special values of log K OA . For different ranges of log K OA , the difference with the regression between log K P and log K OA was also obvious. Compared with our measurement, if 1 order of magnitude difference with log K P values between prediction and measurement was considered, the H-B model, the D-E model and the L-M-Y model can be only used when the log K OA in the ranges from 7.65 to 13.7, 6.88 to 13.5, and 7.65 to 11.7, respectively. Therefore, further studies with prediction models should be conducted for the G/P partitioning of PAHs. The results of this study provided new insights into the research field of the G/P partitioning of SVOCs., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Objectives: The aim of this study was to determine predictors and outcomes associated with staged percutaneous coronary intervention (PCI) versus one-time multivessel revascularization (OTMVR) in patients with multivessel coronary artery disease., Background: Prior observational studies have not evaluated predictors and outcomes of staged PCI versus OTMVR in a heterogenous population of patients with multivessel coronary artery disease who undergo multivessel revascularization., Methods: Data from the Veterans Affairs (VA) CART (Clinical Assessment, Reporting, and Tracking) Program were used to evaluate patients who underwent PCI of >2 vessels between October 1, 2007, and September 3, 2014. Associations between individual factors and the decision to perform staged PCI were assessed. Additionally, the impact of measured patient and procedural factors, site factors, and unmeasured site factors on the decision to perform staged PCI was compared. Cox proportional hazards models were used to determine the association between staged PCI and mortality., Results: A total of 7,599 patients at 61 sites were included. The decision to perform staged PCI was driven by procedural characteristics and unmeasured site factors. Staged PCI was associated with lower risk-adjusted mortality compared with OTMVR (adjusted hazard ratio [HR]: 0.78; 95% confidence interval [CI]: 0.72 to 0.84; p < 0.01). This mortality benefit was observed among the ST-segment elevation myocardial infarction (HR: 0.31; 95% CI: 0.21 to 0.47; p < 0.01), non-ST-segment elevation myocardial infarction (HR: 0.74; 95% CI: 0.64 to 0.87; p < 0.01), unstable angina (HR: 0.75; 95% CI: 0.64 to 0.89; p < 0.01) and stable angina (HR: 0.88; 95% CI: 0.77 to 1.00; p = 0.05) groups., Conclusions: The decision to pursue staged PCI was driven by procedural characteristics and unmeasured site variation and was associated with lower mortality compared with OTMVR. After adjustment, there was an association between staged PCI and reduced mortality. Given the observational nature of these findings, a randomized trial comparing the 2 is needed to guide practice., (Published by Elsevier Inc.)

Background: We studied (1) the rates of stroke or systemic embolism and bleeding in patients with atrial fibrillation and peripheral artery disease (PAD) and (2) the efficacy and safety of apixaban versus warfarin in patients with atrial fibrillation with and without PAD., Methods and Results: The Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) trial randomized 18 201 patients with atrial fibrillation to apixaban or warfarin for stroke/systemic embolism prevention; 884 (4.9%) patients had PAD at baseline. Patients with PAD had higher unadjusted rates of stroke and systemic embolism (hazard ratio [HR] 1.73, 95% CI 1.22-2.45; P=0.002) and major bleeding (HR 1.34, 95% CI 1.00-1.81; P=0.05), but after adjustment, no differences existed in rates of stroke and systemic embolism (HR 1.32, 95% CI 0.93-1.88; P=0.12) and major bleeding (HR 1.03, 95% CI 0.76-1.40; P=0.83) compared with patients without PAD. The risk of stroke or systemic embolism was similar in patients assigned to apixaban and warfarin with PAD (HR 0.63, 95% CI 0.32-1.25) and without PAD (HR 0.80, 95% CI 0.66-0.96; interaction P=0.52). Patients with PAD did not have a statistically significant reduction in major or clinically relevant nonmajor bleeding with apixaban compared with warfarin (HR 1.05, 95% CI 0.69-1.58), whereas those without PAD had a statistically significant reduction (HR 0.65, 95% CI 0.58-0.73; interaction P=0.03)., Conclusions: Patients with PAD in ARISTOTLE had a higher crude risk of stroke or systemic embolism compared with patients without PAD that was not present after adjustment. The benefits of apixaban versus warfarin for stroke and systemic embolism were similar in patients with and without PAD. These findings highlight the need to optimize the treatment of patients with atrial fibrillation and PAD., Clinical Trial Registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00412984., (© 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.)

Objective: The aim of this study was to determine the effect of using a cane on movement time, joint moment, weight symmetry, and muscle activation patterns during sit-to-stand (STS) transfer in healthy subjects and subjects who have had a stroke., Design: Nine subjects with hemiparesis (mean [SD] age, 61.11 [12.83] yrs) and nine healthy adults (mean [SD] age, 63.11 [10.54] yrs) were included. The subjects with hemiparesis performed STS transfer in two randomly assigned conditions: (1) without a cane and (2) with a cane. The healthy subjects performed only STS transfer without a cane. A three-dimensional motion system, force plates, and eletromyography were used to examine STS transfer. The symmetry index between the two limbs was calculated., Results: The movement time of the subjects with hemiparesis in both conditions without a cane and with a cane was longer than that of the healthy subjects without a cane (P < 0.025). However, STS transfer with a cane in the subjects with hemiparesis resulted in shorter movement time, greater knee extensor moment of the paretic limb, and more symmetry of weight bearing than in those without a cane (P < 0.05). The sequence of muscle onset tended to improve with a cane in the subjects with hemiparesis., Conclusions: Cane use may promote more symmetrical STS transfers rather than compensation by the unaffected limb.

Background & Aims: Dysregulation of Wnt signaling has been involved in gastric tumorigenesis by mechanisms that are not fully understood. The receptor for activated protein kinase C (RACK1, GNB2L1) is involved in development of different tumor types, but its expression and function have not been investigated in gastric tumors., Methods: We analyzed expression of RACK1 in gastric tumor samples and their matched normal tissues from 116 patients using immunohistochemistry. Effects of knockdown with small interfering RNAs or overexpression of RACK1 in gastric cancer cell lines were evaluated in cell growth and tumor xenograft. RACK1 signaling pathways were investigated in cells and zebrafish embryos using immunoblot, immunoprecipitation, microinjection, and in situ hybridization assays., Results: Expression of RACK1 was reduced in gastric tumor samples and correlated with depth of tumor infiltration and poor differentiation. Knockdown of RACK1 in gastric cancer cells accelerated their anchorage-independent proliferation in soft agar, whereas overexpression of RACK1 reduced their tumorigenicity in nude mice. RACK1 formed a complex with glycogen synthase kinase Gsk3β and Axin to promote the interaction between Gsk3β and β-catenin and thereby stabilized the β-catenin destruction complex. On stimulation of Wnt3a, RACK1 repressed Wnt signaling by inhibiting recruitment of Axin by Dishevelled 2 (Dvl2). Moreover, there was an inverse correlation between expression of RACK1 and localization of β-catenin to the cytoplasm/nucleus in human gastric tumor samples., Conclusions: RACK1 negatively regulates Wnt signaling pathway by stabilizing the β-catenin destruction complex and act as a tumor suppressor in gastric cancer cells., (Copyright © 2012 AGA Institute. Published by Elsevier Inc. All rights reserved.)

In this paper we investigate trade-offs between speed and accuracy that are produced by humans when confronted with a sequence of choices between two alternatives. We assume that the choice process is described by the drift diffusion model, in which the speed-accuracy trade-off is primarily controlled by the value of the decision threshold. We test the hypothesis that participants choose the decision threshold that maximizes reward rate, defined as an average number of rewards per unit of time. In particular, we test four predictions derived on the basis of this hypothesis in two behavioural experiments. The data from all participants of our experiments provide support only for some of the predictions, and on average the participants are slower and more accurate than predicted by reward rate maximization. However, when we limit our analysis to subgroups of 30-50% of participants who earned the highest overall rewards, all the predictions are satisfied by the data. This suggests that a substantial subset of participants do select decision thresholds that maximize reward rate. We also discuss possible reasons why the remaining participants select thresholds higher than optimal, including the possibility that participants optimize a combination of reward rate and accuracy or that they compensate for the influence of timing uncertainty, or both.

Relational memory, the flexible ability to generalize across existing stores of information, is a fundamental property of human cognition. Little is known, however, about how and when this inferential knowledge emerges. Here, we test the hypothesis that human relational memory develops during offline time periods. Fifty-six participants initially learned five "premise pairs" (A>B, B>C, C>D, D>E, and E>F). Unknown to subjects, the pairs contained an embedded hierarchy (A>B>C>D>E>F). Following an offline delay of either 20 min, 12 hr (wake or sleep), or 24 hr, knowledge of the hierarchy was tested by examining inferential judgments for novel "inference pairs" (B>D, C>E, and B>E). Despite all groups achieving near-identical premise pair retention after the offline delay (all groups, >85%; the building blocks of the hierarchy), a striking dissociation was evident in the ability to make relational inference judgments: the 20-min group showed no evidence of inferential ability (52%), whereas the 12- and 24-hr groups displayed highly significant relational memory developments (inference ability of both groups, >75%; P < 0.001). Moreover, if the 12-hr period contained sleep, an additional boost to relational memory was seen for the most distant inferential judgment (the B>E pair; sleep = 93%, wake = 69%, P = 0.03). Interestingly, despite this increase in performance, the sleep benefit was not associated with an increase in subjective confidence for these judgments. Together, these findings demonstrate that human relational memory develops during offline time delays. Furthermore, sleep appears to preferentially facilitate this process by enhancing hierarchical memory binding, thereby allowing superior performance for the more distant inferential judgments, a benefit that may operate below the level of conscious awareness.

Evidence indicates that sleep after learning is critical for the subsequent consolidation of human memory. Whether sleep before learning is equally essential for the initial formation of new memories, however, remains an open question. We report that a single night of sleep deprivation produces a significant deficit in hippocampal activity during episodic memory encoding, resulting in worse subsequent retention. Furthermore, these hippocampal impairments instantiate a different pattern of functional connectivity in basic alertness networks of the brainstem and thalamus. We also find that unique prefrontal regions predict the success of encoding for sleep-deprived individuals relative to those who have slept normally. These results demonstrate that an absence of prior sleep substantially compromises the neural and behavioral capacity for committing new experiences to memory. It therefore appears that sleep before learning is critical in preparing the human brain for next-day memory formation-a worrying finding considering society's increasing erosion of sleep time.