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When midwives offer birth assistance at home birth and free-standing birth centres, they must adapt their skill set. Currently, there are no comprehensive insights on the skills and knowledge that midwives need to work in those settings. Midwifery care at home birth and in free-standing birth centres requires context specific skills, including the ability to offer low-intervention care for women who choose physiological birth in these settings. To synthesise existing qualitative research that describes the skills and knowledge of certified midwives at home births and free-standing birth centres. We conducted a systematic review that included searches on 5 databases, author runs, citation tracking, journal searches, and reference checking. Meta-ethnographic techniques of reciprocal translation were used to interpret the data set, and a line of argument synthesis was developed. The search identified 13 papers, twelve papers from seven countries, and one paper that included five Nordic countries. Three overarching themes and seven sub-themes were developed: 'Building trustworthy connections,' 'Midwife as instrument,' and 'Creating an environment conducive to birth.' The findings highlight that midwives integrated their sensorial experiences with their clinical knowledge of anatomy and physiology to care for women at home birth and in free-standing birth centres. The interactive relationship between midwives and women is at the core of creating an environment that supports physiological birth while integrating the lived experience of labouring women. Further research is needed to elicit how midwives develop these proficiencies. [ABSTRACT FROM AUTHOR]

• Biomarkers TNF-related apoptosis-inducing ligand (TRAIL), interferon gamma-induced protein 10 (IP-10), and C-reactive protein (CRP) are correlated with COVID-19 severity • TRAIL yielded lower levels and IP-10 yielded higher levels in patients with COVID-19 than in controls • Obesity, CRP, and high peak IP-10 were associated with intensive care unit mortality • Patients with low initial TRAIL levels more often required mechanical ventilation • Including TRAIL, IP-10, and CRP in risk assessment models seems promising Early prognostication of COVID-19 severity will potentially improve patient care. Biomarkers, such as TNF-related apoptosis-inducing ligand (TRAIL), interferon gamma-induced protein 10 (IP-10), and C-reactive protein (CRP), might represent possible tools for point-of-care testing and severity prediction. In this prospective cohort study, we analyzed serum levels of TRAIL, IP-10, and CRP in patients with COVID-19, compared them with control subjects, and investigated the association with disease severity. A total of 899 measurements were performed in 132 patients (mean age 64 years, 40.2% females). Among patients with COVID-19, TRAIL levels were lower (49.5 vs 87 pg/ml, P = 0.0142), whereas IP-10 and CRP showed higher levels (667.5 vs 127 pg/ml, P <0.001; 75.3 vs 1.6 mg/l, P <0.001) than healthy controls. TRAIL yielded an inverse correlation with length of hospital and intensive care unit (ICU) stay, Simplified Acute Physiology Score II, and National Early Warning Score, and IP-10 showed a positive correlation with disease severity. Multivariable regression revealed that obesity (adjusted odds ratio [aOR] 5.434, 95% confidence interval [CI] 1.005-29.38), CRP (aOR 1.014, 95% CI 1.002-1.027), and peak IP-10 (aOR 1.001, 95% CI 1.00-1.002) were independent predictors of in-ICU mortality. We demonstrated a correlation between COVID-19 severity and TRAIL, IP-10, and CRP. Multivariable regression showed a role for IP-10 in predicting unfavourable outcomes, such as in-ICU mortality. Clinicaltrials.gov, NCT04655521 [ABSTRACT FROM AUTHOR]

To understand and interpret the lived experience of newly qualified midwives in their first year in a free standing birth centre caring for women in early labour. Women who present in hospital labour wards in early labour are encouraged by hospital staff to go home. This leaves women to navigate early labour without professional care, leaving them on their own to manage the transition from early to active labour. However, some women request care for this transition. This is a Heideggerian hermeneutic phenomenology study. Three unstructured interviews were conducted with 15 newly qualified midwives in their first year working in a free-standing birth centre. This paper focuses on the research participants' lived experience offering care to women in early labour. The study was conducted from 2021-2024. Three themes were revealed in analysis: " Paving the way into labour ": Tailoring care to women's needs in early labour; " Perhaps it was intuition.": Experiencing deeper knowing as a newly qualified midwife; and " She locked the door and wouldn't let me in.": Navigating uncomfortable situations in early labour. The lived experience of newly qualified midwives offering care in early labour shows potential for midwives to build trusting relationships with women in this phase. Prioritizing relational care over interventions in early labor can enhance trust and confidence between midwives and birthing women, particularly in settings where policies discourage early admissions. Women presenting in hospital labour wards in early labour who are sent home are often discouraged, feeling that their concerns and embodied experiences have not been heard. When labouring women are admitted to hospitals in early labour, they are prone to receive a cascade of interventions. When newly qualified midwives began working in free-standing birth centres, they acquired skills and knowledge to accompany women in early labour who requested care. Relational care in early labour builds women's trust in their ability to give birth and does not rely on interventions to augment labour. [ABSTRACT FROM AUTHOR]

The energy consumption of hydrogen liquefaction is often quantified as being approximately 40 % of hydrogen's lower heating value (LHV), making hydrogen liquefaction energy-intensive. Boundary conditions for energy consumption values in the literature are, however, often unclear, rendering these values questionable. Two methods can nevertheless significantly decrease energy consumption: (1) implementing improved liquefiers; and (2) utilising liquid hydrogen exergy – the reversible liquefaction work – stored in the liquid. Liquid hydrogen exergy equals 11.5 % LHV. And in comparison: per energy content, liquid hydrogen exergy is 5.5 times liquefied natural gas exergy. To estimate the energy savings potential of combining liquefier improvements and exergy utilisation, the exergy efficiency of improved liquefiers is calculated (44 %) and used as a quality measure. The same efficiency is assumed for exergy utilisation processes. The net energy consumption for the liquefaction - regasification chain is thereby reduced to 13-26 % LHV, depending on boundary conditions. • The H 2 liquefaction-regasification chain is evaluated by exergy analyses. • LH 2 exergy is 11.5 % of H 2 's lower heating value (LHV H 2 ), LNG exergy is 2.1 % of LHV CH 4 . • Improved H 2 liquefiers achieve 44 % exergy efficiency. • LH 2 exergy recovery during regasification estimated with liquefier exergy efficiency. • Energy consumption of H 2 liquefaction-regasification chain reducible to 13-26 % LHV H 2 . [ABSTRACT FROM AUTHOR]

Background: Revision total knee arthroplasty (rTKA) rates are increasing in younger patients. Few studies have assessed outcomes of initial aseptic rTKA performed for younger patients compared with traditional-aged patients.Methods: A detailed medical record review was performed to identify patient demographics, medical comorbidities, surgical rTKA indications, timing from index TKA to rTKA, subsequent reoperation rates, component rerevision rates, and salvage procedures for 147 young patients (158 knees) aged 55 years and younger and for a traditional older cohort of 276 patients (300 knees) between 60 and 75 years. Univariate analysis was performed to assess differences in these primary variables, and a log-rank test was used to estimate 5-year implant survival based on either reoperation or component revision and salvage procedures.Results: Younger TKA patients were more likely to undergo initial aseptic rTKA within 2 years of their primary TKA (52.5% vs 29.0%, P < .001) and were more likely to undergo early reoperation (17.7% vs 9.7%, P = .02) or component rerevision (11.4% vs 6.0%, P < .05) after rTKA. Infection and extensor mechanism complications were more commonly noted in younger patients. Estimated 5-year survival was also lower for both reoperation (59.4% vs 65.7%, P = .02) and component rerevision or salvage (65.8% vs 80.1%, P = .02).Conclusion: Early reoperation and component re-rTKA were performed nearly twice as often in younger rTKA than traditional-aged TKA patients. Care should be given to reduce perioperative infection and extensor mechanism failures after rTKA in younger patients. [ABSTRACT FROM AUTHOR]

This paper proposes a method called Zero Gradient Control, which is used to control the heat rejection pressure and the rotational speed of the fans of the gascooler of R-744 refrigeration cycles nearly energy optimal. The basic concept is to develop algebraic terms for the partial derivatives of the COP with respect to the heat rejection pressure and the speed of the fans. These equations are evaluated online with measurement signals and directly fed to decentralized controllers with setpoint zero. The control structure is the same for both sub- and transcritical operation, requires little parameterization and can be applied to a wide range of systems. Using Zero Gradient Control, there is no need to calculate setpoints, which simplifies the mathematical effort in the implementation. Measurements for various scenarios validate the method even in the case of atypical system behavior or gascooler fouling. [ABSTRACT FROM AUTHOR]

Designing a waste heat recovery system (WHRS) for a vehicle to maximize fuel economy is challenging. Interactions with vehicle subsystems, transient boundary conditions, major influence of the operating strategy on the performance and the complexity of the optimization problem must be considered. TLK-Thermo GmbH and the Institute of Thermodynamics at the TU Braunschweig develop a method and the software tool chain MoBA-Lab for the analyzation and optimization of complex thermal systems: 1. Sensitivity analyzes to quantify the influence of system parameters on the system dynamics and the energy efficiency of the system. 2. Operating strategies for maximum energy efficiency. 3. Model-based control to ensure the best possible application of the previously determined operation. By means of the developed method, a design concept of a waste heat recovery system for an omnibus is developed and tested in virtual test drives. The simulated fuel economy leads from 5.8 % for the World Harmonized Vehicle Cycle (WHVC) to 8.1 % for a typical drive from Hanover to Munich. [ABSTRACT FROM AUTHOR]

Unlabelled: This study sought to estimate (1) the prevalence of the co-occurrence of, (2) the association between, and (3) the sequence of onset of chronic pain and mental disorders in adolescents. We used weighted data (N = 6,483) from the National Comorbidity Survey Replication Adolescent Supplement (participants' age, 13-18 years). Lifetime chronic pain was assessed by adolescent self-report; lifetime DSM-IV mental disorders were assessed by the WHO Composite International Diagnostic Interview, complemented by parent report. Among the participants in the study, 1,600 of 6,476 (25.93%) had experienced any type of chronic pain and any mental disorder in their lifetime. All types of pain were related to mental disorders. The most substantial temporal associations were those with onset of mental disorders preceding onset of chronic pain, including those between affective disorders and headaches and any chronic pain; between anxiety disorders and chronic back/neck pain, headaches, and any chronic pain; between behavior disorders and headaches and any chronic pain; and between any mental disorder and chronic back/neck pain, headaches, and any chronic pain.Perspective: Findings indicate that affective, anxiety, and behavior disorders are early risk factors of chronic pain, thereby highlighting the relevance of child mental disorders for pain medicine. To improve prevention and interventions for chronic pain, integrative care should be considered. [ABSTRACT FROM AUTHOR]

Highlights: [•] Method for evaluating fuel saving potential of vehicle waste heat recovery systems. [•] Analysis of interactions between waste heat recovery system and vehicle. [•] Evaluation of fuel saving potential in dynamic motorway driving scenario. [•] Parameter study for increasing fuel saving potential of integrated system. [Copyright &y& Elsevier]

Summary: Context: The rise of cortisol concentrations after awakening is well documented in adults and children and commonly used as easily accessible marker of hypothalamic-pituitary-adrenal (HPA) reactivity. Objective: The purpose of this study was to demonstrate the existence of a salivary cortisol awakening response (CAR) in infants, and to estimate its association with birth outcome. Setting: The study was conducted in the general community. Participants: Healthy infants up to six months age (N =64). Main outcome measures: Mothers were instructed to collect their infant's saliva immediately and 30min after awakening on two days within 45 days, irrespective of awakening time. Information on birth outcome was collected from medical records and questionnaires. Results: Linear mixed models analysis revealed a significant rise of infant salivary cortisol concentrations within 30min after awakening (b =0.128, SE=0.024, t 61 =5.31, p <0.001), which was quite stable across the two sampling days (r =0.40, p =0.002). The infant CAR was predicted by length of gestation (t 58 =2.44, p =0.018). Conclusions: The current data demonstrate the existence of a CAR in infants as early as during the first six postnatal months; its relationship with length of gestation supports its usefulness for questions related to developmental neuroscience. Therefore, the infant CAR emerges as non-invasive biomarker of HPA axis dynamics at this early stage of life, with relevance for future research and potential clinical applications. [Copyright &y& Elsevier]

Visual abstract: The Embodied Driving (EMBODD) model of automated mobility. Abbreviations: SAE, SAE international's J3016, taxonomy and definitions for terms related to driving automation systems. • Highly automated driving will change future mobility, potentially affecting users' psychobiological state. • We systematically reviewed evidence of the psychobiology related to automated driving. • This knowledge may inform how drivers' states should be modified and improved. • As theoretical basis, we propose the Embodied Driving (EMBODD) model. • We provide recommendations for conducting and reporting studies in the field. Using vehicles with engaged automated driving systems (ADS) ('highly automated driving', HAD) will substantially impact on future society's mobility, yet the current understanding of human psychobiology related to HAD is still limited. Hence, we synthesized evidence on the psychobiology of subjects using HAD, informing an integrative model of the psychobiology of HAD, and providing guidance for reporting future research on this topic. We included (non-)randomized studies assessing human peripheral biology markers of in-vehicle-users in real or simulated driving environments, using vehicles with vs. without engaged ADS, published in English until April 2018. We systematically searched Web of Science, SCOPUS, and PubMed. The search consisted of a combination of terms describing HAD and psychobiological parameters. Risk of bias was assessed regarding randomization, blinding, incomplete outcome data, selective outcome reporting, and other potential causes. We extracted data using predefined data fields. Four out of five studies included in this review (N = 194 subjects) reported associations of use of vehicles with vs. without engaged ADS with various psychobiological parameters, including heart rate, respiratory sinus arrhythmia (RSA), indicators of electrodermal activity (EDA), and masseter electromyography (EMG). Heart rate tended to be reduced during HAD along with increased EDA and EMG, with no clear indication for changes in RSA. We cannot exclude substantial risk of bias, among others because the status of engagement of ADS was mostly non-randomized. Yet, findings suggest that HAD goes along with tractable changes in peripheral biology. Informed by the conceptual endophenotype approach (Hellhammer et al., 2018 , Psychoneuroendocrinology), we propose the Embodied Driving (EMBODD) model that describes how HAD reshapes vehicle use experience, and highlight how to make future ADS equipped vehicles successful regarding user's health. Based on the review, we suggest reporting guidelines for future research on the psychobiology of HAD. [ABSTRACT FROM AUTHOR]

A method for calculating the thermophysical properties of the blend R-445A is presented. The data were then employed in a transient simulation of an R-134a air conditioning system in a city bus operating with R-445A to evaluate the blend under transient boundary conditions. The cumulated COP of the reference R-134a system, derived from the cumulated cooling capacity divided by the cumulated compressor power, is ca. 3.9. Using R-445A as drop-in, the cumulated COP is ca. 8% lower, and also the maximum cooling capacity is reduced, whereas the high pressure and the compressor outlet temperature increase. Furthermore there is a higher risk of ice formation at the evaporator. Selective leakage of R-445A may cause a COP increase and a maximum cooling capacity decrease over the operation time. [ABSTRACT FROM AUTHOR]

• Girls are better able to delay gratification than boys. • Boys with higher prenatal testosterone levels are less able to delay gratification. • Boys with higher prenatal testosterone levels show more attentions problems/overactive behavior. • Boys with more attention problems/overactive behavior are less able to delay gratification. Sex differences in self-control become apparent during preschool years. Girls are better able to delay their gratification and show less attention problems and overactive behavior than boys. In this context, organizational effects of gonadal steroids affecting the neural circuitry underlying self-control could be responsible for these early sex differences. In the present study testosterone levels measured in amniotic fluid (via ultra performance liquid chromatography and tandem mass spectrometry) were used to examine the role of organizational sex hormones on self-control. One hundred and twenty-two 40-month-old children participated in a delay of gratification task (DoG task) and their parents reported on their attention problems and overactive behavior. Girls waited significantly longer for their preferred reward than boys, and significantly more girls than boys waited the maximum period of time, providing evidence for sex differences in delay of gratification. Boys that were rated as suffering from more attention problems and overactive behavior waited significantly shorter in the DoG task. Amniotic testosterone measures were reliable in boys only. Most importantly, boys who waited shorter in the DoG task and boys who were reported to suffer from more attention problems and overactive behavior had higher prenatal testosterone levels. These findings extend our knowledge concerning organizational effects of testosterone on the brain circuitry underlying self-control in boys, and are of relevance for understanding how sex differences in behavioral disorders are connected with a lack of self-control. [ABSTRACT FROM AUTHOR]

Abstract Induced pluripotent stem cells (iPSCs) were first described over a decade ago and are currently used in various basic biology and clinical research fields. Recent advances in the field of human iPSCs have opened the way to a better understanding of the biology of human diseases. Disease-specific iPSCs provide an unparalleled opportunity to establish novel human cell-based disease models, with the potential to enhance our understanding of the molecular mechanisms underlying human malignancies, and to accelerate the identification of effective new drugs. When combined with genome editing technologies, iPSCs represent a new approach to study single or multiple disease-causing mutations and model specific diseases in vitro. In addition, genetically corrected patient-specific iPSCs could potentially be used for stem cell based therapy. Furthermore, the reprogrammed cells share patient-specific genetic background, offering a new platform to develop personalized therapy/medicine for patients. In this review we discuss the recent advances in iPSC research technology and their potential applications in hematological diseases. Somatic cell reprogramming has presented new routes for generating patient-derived iPSCs, which can be differentiated to hematopoietic stem cells and the various downstream hematopoietic lineages. iPSC technology shows promise in the modeling of both inherited and acquired hematological disorders. A direct reprogramming and differentiation strategy is able to recapitulate hematological disorder progression and capture the earliest molecular alterations that underlie the initiation of hematological malignancies. [ABSTRACT FROM AUTHOR]

• Development of two test stations studying biofouling on artificial test bodies. • Both systems met necessary requirements under harsh environmental conditions. • A sound basis for characterization of fouling communities and impact assessment. • Systems present possibilities for further developments for other research approaches. The enhanced inertia load caused by biofouling on device components, such as the foundations of wind turbines or other structures at sea, modifies the hydrodynamic properties, and increases the stress to structures, predominantly in upper water layers with high impact from wave dynamics. This compromises the stability, functioning, operation as well as the durability of these devices especially in exposed environments. A main challenge is the quantification of the impact of hydrodynamic forces on irregular bodies being overgrown by soft- and hard-bodied biofouling organisms. Therefore, test bodies from the upper 1–5 m water depth and thus exposed to the strongest wave actions close to the surface shall be overgrown by biofouling and used in measurement trials in a wave and current flume. These measurements shall shed light on the varying roughness and its influence on the load bearing capacity of foundation piles. Consequently, the main aims of the present work were the development of two independent test stations as holding devices for artificial test bodies for the collection of biofouling organisms during field studies: a carrying unit floating at the surface in an exposed area (System A) and a sampling device with access from a land-based facility (System B). Both systems are relatively easy to access, exhibit straightforward handling, and are reasonable cost-effective. A Test Body Support Unit (TBSU, System A) was designed and mounted on a spare buoy to carry the test bodies (cylinders), which serve as substrate for the fouling. The system was sufficiently robust to withstand several periods of rough sea conditions over the first two years. This system can only be accessed by vessels. System B (MareLift) provided the robustness and functionality needed for areas exhibiting harsh conditions but can be operated from land. The here used test bodies (steel panels) exhibited a sound basis for the monitoring of succession processes in the biofouling development. System B offered the possibility to analyse two habitats (intertidal and subtidal) and revealed clear differences in the composition and development of their fouling communities. Overall, both systems provide advantages in obtaining standardized biofouling samples compared to previous approaches. Such test stations play an important role in the risk management of marine sectors as they could help characterising biofouling communities over different geographical areas. System A and B provide a sound basis for biofouling research but potentially also for other potential research approaches in exposed areas as they provide space for future developments. [ABSTRACT FROM AUTHOR]

This paper proposes a novel fuel cell stack model for system simulation of the cold start operation. The stack model features the option of spatial resolution in two directions and can simulate two-phase effects that are prone to occur during cold start. These effects include: the sorption process in the triple-phase zone between the membrane and the catalyst layer; the condensation, freezing and evaporation in the porous layers; the two-phase flow in the gas channels with a gas–liquid slip model. Compared to a 0D lumped model, the proposed stack model provides a more detailed view of the onset of freezing and liquid saturation. In a freeze start simulation from −20 °C, the Rapid-Warmup-Operation published by Naganuma et al. [1] is applied and demonstrated as an effective way to quickly elevate stack temperature to +5 °C within 30 s. The stack model illustrates in detail the physical phenomena in the cold start and can be further integrated into a powertrain model for drive cycle analysis. [ABSTRACT FROM AUTHOR]

Abstract: Helplessness is a major concept in depression and a major theme in preclinical and clinical depression research. For example, in rodents and humans, the learned helplessness (LH) effect describes a specific deficit in behaviour to control aversive stimuli that is induced by prior exposure to uncontrollable aversive stimuli. The LH effect is objective and valid in that the cause of the behavioural deficit, namely uncontrollability, is clear; furthermore, the deficit induced is underlain by emotional, motivational and cognitive processes that are relevant to depression psychopathology. As a further example, helplessness, hopelessness, external locus of control and causal attribution are inter-related and major themes in psychological theories (primarily cognitive theories) of depression. Despite this broad interest in helplessness, it can be argued that its potential usefulness as a scientific and clinical concept has so far not been investigated optimally, including with respect to its application in research aimed at development of improved anti-depressant pharmacotherapy. The first aim of this review was to describe and integrate the psychological evidence and the neurobiological evidence for the LH effect in rodents and healthy humans and for helplessness in depressed patients. The second aim was to conduct three systematic reviews, namely of rodent studies of the LH effect, rodent studies of effects of psychopharmacological agents on the LH effect, and human studies of efficacy of pharmacotherapeutic and psychotherapeutic treatment on helplessness in depressed patients. With respect to the first aim, the major findings are: the specificity of the LH effect in otherwise non-manipulated rodents and healthy humans has been under-estimated, and the LH effect is a specific learned aversive uncontrollability (LAU) effect. There is theoretical and empirical support for a model in which a specific LAU effect induced by a life event of major emotional significance can function as an aetiological factor for generalised helplessness which can in turn function as an aetiological and maintenance factor for depression. However, to date such models have focused on cognitive mediating processes whereas it is emotional–motivational–cognitive processes (as proposed for the LAU effect) that need to be invoked and understood. The evidence is for analogous neural processes underlying the LAU effect in rodents and healthy humans and helplessness in depression, with the ventro-medial prefrontal cortex exhibiting aversive uncontrollability-dependent activity. With respect to the second aim, the major findings are: the LAU effect is demonstrated quite consistently using a number of different paradigms in rat but is poorly studied in mouse. The rat LAU effect can be reversed by chronic administration of monoamine reuptake inhibitors. The effects of antidepressants on human helplessness have been scarcely studied to-date. The major conclusion is that the LAU effect and generalised helplessness constitute major neuropsychological concepts of high value to future translational research aimed at increased understanding of depression and development of novel, improved antidepressant treatments. [Copyright &y& Elsevier]

Abstract: Adsorption refrigeration systems provide a sustainable possibility to reduce the environmental impact of refrigeration and air-conditioning as they allow for sources of otherwise unused excess waste heat to be reused for cooling purposes. Adsorptive cooling is a discontinuously operated cycling process, and it is well known that the determination of an optimal cycling time yielding maximum cooling power is a key to the design of an efficient mode of operation. The optimal cycle time however strongly depends on operating conditions such as ambient air temperature, available heat source temperature, desired target cooling temperature, and achievable volume flow rates of the secondary heat transfer circuits. In this contribution, we apply a direct method for periodic optimal control to optimize two-bed adsorption chillers. We present a first principles dynamic model of the underlying thermal process. We show that direct methods for periodic optimal control allow for quick and reliable computation of optimal cycle times for a given set of parameters. Contrary to pre-existing methods, fast computation times and guaranteed optimality of the solutions computed by our approach makes it viable to extensively study the simulated optimal cyclic operation of two-bed adsorption chillers under a wide range of varying conditions. [Copyright &y& Elsevier]

• Testosterone and estradiol from amniotic fluid were correlated with infants' performance on a mental rotation task and an index of vigilance. • For 6-months-old boys (N = 104) mental rotation but not vigilance was correlated with prenatal testosterone but not with estradiol. • For 6-months-old girls (N = 104) mental rotation but not vigilance was correlated with prenatal estradiol but not with testosterone. • In both cases, only about 5% of the within-sex variance in mental rotation performance was due to prenatal sex hormones indicating small effects. Sex differences in mental rotation, robust in adults, have recently been reported for infants' looking times although the pattern of results is not completely conclusive. In this context, organizational effects of gonadal steroids affecting the neural circuitry underlying spatial cognition could be (partly) responsible for the early sex difference. In the present study testosterone and estradiol levels measured in amniotic fluid via ultra performance liquid chromatography and tandem mass spectrometry were used to examine the role of prenatal sex hormones on infants' looking times during mental rotation. N = 208 six-month-old infants participated in an expectation of violation task with 3D cube figures. Mental rotation was defined as the difference in looking times for familiar versus mirrored cube figures whereas vigilance was defined as the sum of both looking times. Sex differences were absent for mental rotation as well as for vigilance. Most importantly, however, for boys mental rotation but not vigilance was correlated with prenatal testosterone but not with estradiol. For girls mental rotation but not vigilance was correlated with prenatal estradiol but not with testosterone although it has to be noted that the testosterone values for girls suffered from a floor effect. Only 5% of the within-sex variance was due to prenatal sex hormones indicating small effects. These findings extend our knowledge concerning organizational effects of prenatal sex hormones on the brain circuitry underlying spatial cognition. [ABSTRACT FROM AUTHOR]