Also, this new anode material exhibits low potential (0.2 V versus lithium) and one of the highest specific capacity ever reported at low C-rates (7.3 mAh cm−2 at 0.1 C). We show that the outstanding cyclability is the result of a combination of many factors, including limited volume expansion, as supported by density functional theory calculations. This finding opens new opportunities in design of long-lasting integrated energy storage for self-powered microsystems.Long-term stability is one of the most desired functionalities of energy storage microdevices for wearable electronics, wireless sensor networks and the upcoming Internet of Things. Although Li-ion microbatteries have become the dominant energy-storage technology for on-chip electronics, the extension of lifetime of these components remains a fundamental hurdle to overcome. Here, we develop an ultra-stable porous anode based on SnAu alloys able to withstand a high specific capacity exceeding 100 µAh cm This trendy concept describes a network of connected objects able to collect data, interact with the environment and communicate wirelessly over the internet for a plethora of applications such as healthcare, self-driving vehicles, environmental monitoring and smart manufacturing. The integration of self-powered micrometric sensors will rely on efficient microscale energy storage units3 to interface with various types of energy harvesters, which are intermittent by nature. The inherent requirement is to enable monitoring by a remote sensor without further maintenance. Microbatteries with high areal capacity and ultralong life cycle are thus quintessential in such a scenario for realizing “fit and forget” type solutions. Moreover, microbatteries will be confined in an embedded microsystem with limited space available. The size and the compactness being critical, it is imperative to consider their properties normalized to the surface area. This calls for utilization of innovative materials with high volumetric capacity coupled with exploitive architectures, which are easy to realize and compatible with microsystem fabrication technologies, providing robust stability in limited footprint area. Furthermore, pricey electrode materials can be used in miniaturized devices, where cost is mainly determined by the microfabrication process and not by the minute amount of active materials involved.With ultrahigh speed rate and low latency of 5 G mobile networks in the upcoming years, the emergence of the Internet of Things (IoT) is set to revolutionize all aspects of our lives9. Especially, Sn and their oxides have extremely high volumetric capacity  and hence apt for utilization in microbatteries requiring high energy density per footprint area. However, Sn anodes suffer from a variety of issues like volume expansion (up to 360%), related continuous solid electrolyte interface (SEI) formation and capacity fading11. Such issues are magnified in context of microbatteries, where there are not many amenities for structural engineering due to limited space. Nevertheless, there have been several efforts to utilize Sn-based materials in microbatteries – through alloying with other metal14 constructing porous 3D architectures21 making homogenous/ordered carbon composites26 etc. However, most of them failed to achieve long cyclability and high rate capability. In the cases where high rate was demonstrated, the charge-discharge profile was more capacitive than battery-like24.Alloy anodes are promising candidates as negative electrodes in Li and post Li-ion chemistries due to their high specific capacityxSnAu alloys with exceptional cycling stability (exceeding 6 000 cycles) and rate capability (>150 µAh/cm2 at 4 C) with flat discharge profile even at high rates. The tin gold alloy is homogeneously formed onto nanoporous structures prepared using the dynamic hydrogen bubble template (DHBT) method, by which 3D self-supported metallic structures, with a wide range of interconnected pores, are electrodeposited and sculptured by H2 bubbles generated at high overpotentials27. The obtained porous alloy film (10–100 μm thick) is conductive, evolves into further nanoporous structure upon reaction with Li and exhibits remarkable mechanical stability upon lithiation, even using a standard liquid-based electrolyte, with limited volume expansion as established by DFT modelling. This finding represents a major step forward towards the integration of high-energy long-cycling microbatteries for IoT applications.Here, we report on highly porous anodes based on Li29. However, for commercial upscaling, galvanostatic deposition is preferred and hence, in the present work, an optimized protocol with constant current deposition was utilized. Various parameters like concentration of Au3+ ions, acid concentration, deposition time and stability of the porous films over time were varied individually to reach a set of optimized deposition conditions  of porous gold films used in this study are t = 59 μm, p = 88.0% and AR = 900 cm2/cm2. This huge area to volume ratio allows more active material to be loaded per unit area of electrode and results in better interfacial kinetics and lower ohmic losses due to short transport distances32. Moreover, with such high porosity, little amount of gold is involved and cost of current collector material is estimated to be less than 30 cents cm−2. The porous nature of the resulting electrodeposited film can be observed in the scanning electron microscope (SEM) images of Supplementary Fig. Highly porous metallic current collectors were first prepared using the dynamic hydrogen bubble template (DHBT) method on a silicon substrate. A key advantage of this technique is its cleanliness, simplicity, and ease of preparation, making the DHBT method easily transferable to pilot production line in microelectronic facilities. DHBT was used to prepare highly porous gold architectures onto which Sn was subsequently deposited  resulted in pure Sn phases rather than SnAu alloys  in order to realize porous Sn based electrodes having flat charge-discharge plateaus due to formation of self-nanoporous structure upon lithiationges Fig. , the morges Fig. , both Snges Fig. . Surpris(Sn)−1) by considering deposited weight of Sn alone as active material −1  is now providing the reversible capacity. In addition, it is known that the stannides of the family LixSnyAuz (for e.g. Li2Sn2Au has DLi(max) = 1.5 × 10−6 cm2 s−1 at 25 °C) exhibit good Li+ diffusion coefficients even at low Li content41 and hence, the presence of Li2SnAu after long cycling might also possess efficient Li+ transport properties in the electrode. The electrochemical lithiation of conformally deposited SnAu alloy not only gives high reversible specific areal capacity, but also results in intermediates that favor Li+ ion diffusion kinetics, displaying its superiority as a prospective anode material for Li-ion microbatteries.This is also in agreement with galvanostatic charge discharge measurements Fig. . The lit/Li Fig.  also inc/Li Fig. . The ele6 based liquid electrolyte without any additives for demonstration effects  and consistent with a homogeneous distribution of the active material within unalloyed porous Au framework which provides good electronic conductivity to the matrix even after long cycling. C-rates studies were also carried out to see the robustness of the electrode towards rate fluctuations .Electrochemical impedance spectroscopy (EIS) studies were performed before cycling and after 2 000 cycles Fig. . The oveons Fig. . The ele2SnAu to Li4.2SnAu. More impressively, the samples feature superior cyclability, sustaining more than 6000 cycles with an average capacity decay below 10 nAh cm−2 per cycle. During initial cycles, decrease in specific capacity can be ascribed to rearrangements in the electrode due to volume expansion, which exposes new surface for lithiation and continuous SEI formation. However, after the pre-cycling treatment, the discharge capacity was very stable due to homogeneous distribution of the lihtiated intermediates within the electron conducting porous gold framework and limited volume expansion, which is further corroborated by DFT studies.Extra long-term cyclability of the electrodes was evaluated at 3 C rate due to time constraints, using samples synthesized with different electrodeposition times Fig. . The elexSn and LixSnAu during the lithiation/delithiation process using DFT calculations ). DFT shows that this reaction involves different phase transformations . This “pre-treatment” regime is then quickly followed by an extreme stability for the rest of the lifetime of the cells, whatever the mass loadings of the electrode  is therefore associated with a volume change which is more than 5 times lower than the one related to the conversion of Sn to Li4Sn. Moreover, the void space of the porous structure can accommodate this limited volume expansion of the active material, making porous Li2SnAu a very promising anode for long-term cycling microbatteries.Regarding SnAu alloy, as stated before, its first lithiations lead to the formation of Liode Fig. . Taking −2) anodes. The entire 3D structure is compact (<0.8 cm2) and can be assembled on silicon wafers to facilitate their microelectronics based integration. Conformal coating of these highly porous substrates with active materials (SnAu) is also realized under ambient conditions through simple electroplating technique to ensure ease of further upscaling. Explanations over origin of high stability and mechanism of charge storage are also provided from materials/electrochemical characterizations and DFT simulations, thus opening a niche for further development of these 3D porous engineered architectures. Further research focus on upgradation of these 3D micro-architectures will be to fabricate full devices in interdigitated configuration with solid electrolytes, develop efficient packaging routes and trail integration with other microelectronic components. Moreover, replacing the liquid electrolyte with a solid electrolyte should further enhance the stability and durability, giving rise to even higher energy storage and cyclability. The work also illustrates the utilization of significantly different material chemistry for microbatteries, which can be investigated further by changing individual elements and analyzing their electrochemical kinetics. Overall, we demonstrate successful microengineering of 3D porous architectures for Li-ion microbatteries with tremendous potential as integrative miniature power sources for microdevices.In the current work, we have reported 3D porous current collector based microbattery architecture for ultra-long life cycle (>6000 cycles) and extremely high areal capacity  in 1 M H2SO4 until a stable voltammogram was obtained. Porous metallic current collectors were prepared using the DHBT technique from an optimized solution of 2 × 10−3 M of HAuCl4.3H2O in 3 M H2SO4 by applying 5 A cm−2 for 20 min in a 3-electrode configuration. The porous Au film was then washed several times in de-ionized water before vacuum drying for 30 min. SnAu alloy formation was then carried out by electrodeposition from a freshly prepared solution of 7.5 × 10−3 M of SnCl2 in 0.02 M HCl by applying -2 V vs. SCE for 1, 3, 6, 10 min with mass loadings of ∼2.9 mg cm−2 of SnAu per min. The electrodes (0.8 cm2) were further dried to remove any moisture content and tested using Li-ion half-cells (EL-Cell) assembled in a glove box with purified argon, with lithium foil as counter and reference electrodes, and glass fiber separator soaked with 1 M LiPF6 in ethylene carbonate (EC)/diethyl carbonate (DEC) (1:1 volume ratio).A Ti(100 nm)/Au(300 nm) thin film was deposited by evaporation on an oxidized silicon substrate and electrochemically pretreated by cycling the potential at a scan rate of 100 mV svs. Li/Li+) for two cycles at 0.1 C (0.1 mA cm−2) before ramping the rate. The surface morphology of the electrodes was examined by scanning electron microscopy (SEM) on a Hitachi S-4800 field emission electron microscope. The crystallographic structures were analyzed by grazing incidence X-ray diffraction (XRD) measurements on a Bruker D8 Advanced X-ray diffractometer with Cu Kα radiation (1.54184 Å), operating at 40 kV and 40 mA. DFT-based Vienna ab initio simulation package (VASP) was employed to perform calculations, using Perdew, Burke, and Ernzerhof (PBE) method for treating exchange and correlation. The valence electrons were described with a planewave basis set. Nuclei and core electrons were treated with pseudo-potentials of the projector augmented wave type. The aspect ratio AR of the metallic current collector was defined as follows:The electrochemical synthesis and characterizations were performed with a VMP-3 and a VSP Biologic potentiostat connected to an external 10 A booster channel. The amount of Sn reduced was calculated using Faraday’s law. Subsequently, assuming all of the reduced Sn underwent alloying with Au to form SnAu (since there was no peak corresponding to pure Sn in XRD for any of the samples), the weight of active material was obtained. The content ratio of SnAu (1:1) was obtained from XRD measurements. This was also confirmed from the obtained capacity which matched the theoretical capacity for lithiation of SnAu. For long life cycle studies, the cells were initially pre-cycled in the same potential range (0.02–1.5 V −2 44 The porosity p (%), describing the fraction of void space in the material, was calculated using the following equation:Vp is the pore volume, V the apparent volume of the electrode, S the geometric electrode surface, t the film thickness, w the weight of the deposited gold and ρAu the density of gold set at 8.9 g cm−3.The electrochemical surface area of porous gold was calculated using the charge associated with the reduction of gold oxide, using a value of 390 μC cmSupplementary information.


Eg of a semiconductor—often determined by means of optical spectroscopy—represents its characteristic fingerprint and changes distinctively with temperature. Here, we demonstrate that in magic sized II-VI clusters containing only 26 atoms, a pronounced weakening of the bonds occurs upon optical excitation, which results in a strong exciton-driven shift of the phonon spectrum. As a consequence, a drastic increase of dEg/dT (up to a factor of 2) with respect to bulk material or nanocrystals of typical size is found. We are able to describe our experimental data with excellent quantitative agreement from first principles deriving the bandgap shift with temperature as the vibrational entropy contribution to the free energy difference between the ground and optically excited states. Our work demonstrates how in small nanoparticles, photons as the probe medium affect the bandgap—a fundamental semiconductor property.The fundamental bandgap  The bandgap of nanostructures usually follows the bulk value upon temperature change. Here, the authors find that in small nanocrystals a weakening of the bonds due to optical excitation causes a pronounced phonon shift, leading to a drastic enhancement of the bandgap’s temperature dependence. Eg, through size control on the nanometer scale is a key attribute of semiconductor nanocrystals, enabling applications2 spanning from biomedical imaging3 to optoelectronic devices such as light emitting diodes5 and photodetectors6. The bandgap of semiconductors with reduced dimensions can usually be derived from the bulk value, correcting for electronic perturbations8, such as charge carrier quantization and Coulomb interaction. Although the electronic structure of semiconductor nanocrystals is changed by quantum confinement, the temperature dependence of the bandgap usually appears to be dominated by bulk mechanisms in both epitaxial10 as well as most colloidal quantum dots (QDs)16. However, there are few examples19 that reported conflicting results on the temperature dependence of the bandgap in quantum dots, opening room for debate. For bulk, it is widely accepted that the temperature dependence of the bandgap results from a superposition of electron–phonon interactions and thermal lattice expansion21. Besides widely used empirical equations22, the AHC approach25 , which is based on second-order perturbation theory, approaches the temperature-induced bandgap shift as the change in energy levels when phonons are thermally populated. This has been used to obtain the temperature dependent bandgap computationally for a number of bulk semiconductors26. Following semi-empirical approaches, AHC was subsequently combined with density functional theory (DFT) or density functional perturbation theory (DFPT)30. For nanocrystals, the temperature dependence of the bandgap has been derived either (i) as time average of the bandgap with first principle molecular dynamic (MD) calculations33, or (ii) via the frozen-phonon approach36, summing over the Bose–Einstein weighted changes in eigenenergies due to atomic displacements along the different phonon modes.The tunability of the fundamental bandgap, 40 (MSC) containing a defined number of 26 atoms, a pronounced exciton-induced weakening of the crystal bonds occurs, resulting in a giant shift of the phonon spectrum driven by the exciton. As a consequence, a drastic increase of dEg/dT (up to a factor of 2) with respect to bulk material or nanocrystals of typical size is found. Using a first principles approach, we computed the exciton-induced change of the phonon density of states from molecular dynamics simulations on the excited state potential energy surface. This enabled us to quantitatively describe our experimental data by deriving the bandgap shift with temperature as the vibrational entropy contribution to the free energy difference between the ground and optically excited states.Here, we demonstrate that the impact of temperature on the optical bandgap is fundamentally altered in materials at the border between solids and molecules. In magic sized clusters13 MSCs. The absorption of (CdSe)13 MSCs, which is dominated by multiple resonances affiliated to the fine structure of the lowest excitonic transition41, exhibits a redshift with increasing temperature for the whole collectivity of peaks of about 160 meV 41 offers additional possibilities to track the bandgap shift for specific fine structure states. The sp-d exchange interactions, which persist up to room temperature in these clusters43, generate a pronounced magneto-optical response at the bandgap, representing a powerful tool to distinguish between magneto-optically active and inactive states via magnetic circular dichroism (MCD) spectroscopy , the shift of the bandgap slightly exceeds that of the undoped clusters  accounts for 164 ± 16 meV  spectroscopy reveals a shift of about 200 meV of the bandgap absorption between 5 and 300 K 13 MSCs44 prepared for comparison exhibit a similarly enhanced temperature dependence as the CdSe based MSCs . For (CdSe)13 MSCs, our data reveals a mean increase of 89 % compared to bulk CdSe (wurtzite) for the high temperature limit of dEg/dT (between 150 and 300 K) among 14 data sets 13 MSCs between the ground and the optically excited states as a function of temperature using constrained DFT. We performed the same set of calculations for the two most prominent structural models for the (CdSe)13 MSCs48: the so-called sliced-wurtzite MSC without ligands  is the phonon density of states (PDOS). The first optically bright transition in the (CdSe)13 MSC is the HOMO→LUMO+1 transition   ≈ g), we obtain the bandgap shift with temperatureT < 150 K, the measured and calculated temperature-dependence of ΔEg agree very closely. At higher temperatures, the experimental data deviate slightly from a perfectly linear behavior, indicating anharmonic contributions to the free energy.To obtain the excited state PDOS, we constrained the electron occupations of the orbitals, so that one electron from the HOMO is transferred to the LUMO+1 state. We calculated the phonon frequencies, T = 300 K, we obtained a slight overestimation for the temperature-dependence of the bandgap  using Gaussian functions as a basis set and interpolated between the PDOSs at T = 0 K and T = 300 K (see “Methods”). As shown in Fig. g (green dashed line) is in excellent agreement with the experiments within the whole measured temperature range.In order to explicitly account for the temperature-dependence of the phonon frequencies, we used the same constrained DFT approach to perform ab initio MD calculations to obtain the PDOS at 300 K (see Methods). Inserting the ground and excited state PDOSs for 33, which distributes the atomic velocities according to classical Maxwell-Boltzmann statistics instead of Bose–Einstein occupation of the vibrational modes, and thus inherently overestimates dEg/dT at low temperatures, or (ii) by summing over Bose–Einstein weighted eigenenergy changes induced by frozen-phonon modes36. The latter is known to severely overestimate the temperature dependence of the bandgap in nanocrystals36, often attributed to overrated contributions of surface and ligand modes. Indeed, we obtain an overestimation by almost an order of magnitude, calculating the bandgap shift with temperature based on a frozen-phonon approach  as the mean HOMO-LUMO energy difference in a MDω ≪ kBT), the slope of the temperature-induced band gap shift can be estimated asEg/dT in nanoclusters compared to bulk: (i) Softer phonon modes in general compared to bulk, e.g. due to surface related acoustic modes, and (ii) an enhanced change Δω in the phonon energies due to the absorption process. The former has been predicted for PbS53 and Si35, while for CdSe nanoparticles theoretically55 and experimentally54 a blueshift of the acoustic surface modes has been observed. Our calculations reveal a distinct redshift in the acoustic modes for the core-cage nanocluster model compared to bulk, while the data exhibit no clear shift for the sliced-wurtzite structure . Both structures reveal enhanced temperature-induced bandgap shifts 2, ZnCl2(octylamine)2, and MnCl2(octylamine)2) and octylammonium selenocarbamate (0.67 M) in n-octylamine . For Mn2+:(CdSe)13 MSCs, 1.0 mmol of CdCl2 and 0.1 mmol of MnCl2 were heated in 7 ml of n-octylamine at 120 °C for 2 h. The average doping concentration is changed by adjusting the initial precursor ratio (MnCl2/CdCl2). Octylammonium selenocarbamate was prepared by bubbling CO gas into 3 ml of n-octylamine containing 2.0 mmol Se powder for 1 h at room temperature. This solution was injected into the as-prepared precursor mixture containing metal-ammine halide complexes and kept at room temperature for more than 24 h. The MSCs were precipitated by adding ethanol containing trioctylphosphine followed by washing several times with ethanol3. For the synthesis of Mn2+:(ZnSe)13 MSCs, ZnCl2 was used instead of CdCl2. The average doping concentration of the MSCs was measured by inductively coupled plasma-atomic emission spectrometry . To enhance the dispersibility of MSCs, which results in minimization of light scattering, the initial octylamine ligands were exchanged with long-chain oleylamine ligands1. CdSe QDs and CdSe/ZnS QDs were synthesized by conventional hot injection method using Cd(oleate)2 and trioctylphosphine selenide (TOPSe) as precursors56. In all, 1.2 mmol CdO were added to a mixture of 1.5 mL of oleic acid and 20 mL of 1-octadecene and heated under vacuum for 2 h at 120 °C to form Cd(oleate)2 complexes. The mixture was then heated to 300 °C under Ar and TOPSe (1 M) was rapidly injected to obtain CdSe QDs. For the growth of ZnS shells, 4.8 mmol of Zn(oleate)2 and 4.8 mmol of tributylphosphine sulfide were additionally introduced to the as-prepared solution containing CdSe QDs and the reaction mixture was kept at 300 °C for 20 min. For CdSe QDs and CdSe/ZnS QDs, we also performed a surface modification with oleylamine to neglect the effect of the surface ligands.Nanocrystals and MSCs used in this study were synthesized using standard Schlenk techniques under an argon atmosphere. The MSCs were obtained from a Lewis acid-base reaction between metal-ammine halide complexes  and magnetic circular dichroism (MCD) measurements the MSCs passivated by oleylamine were prepared as thin films between two quartz glass substrates, and for PL measurements between a silicon and a quartz glass substrate. MCD spectroscopy was conducted on a homemade setup consisting of a 75 W Xenon lamp (Lot-Oriel) equipped with a monochromator  and a photomultiplier . The excitation light was modulated using a photoelastic modulator . The sample was placed in a helium vapor cryostat  between two poles of an electromagnet  in Faraday geometry. Absorption measurements were either extracted from the DC signal during MCD measurements or collected with an UV-VIS spectrophotometer (Shimadzu 2550) equipped with a helium vapor cryostat . PLE measurements were conducted with a helium vapor cryostat  placed in a Fluorolog-3 . For time resolved analysis of the PL signal the samples placed in a helium vapor cryostat  were excited with a frequency tripled Ti:sapphire laser  pumped with an Nd:YAG laser  with 100 fs pulses at a repetition rate of 76 MHz. The signal was detected with a streak camera system consisting of a monochromator  and a Synchroscan Streak camera , providing a temporal resolution of 4 ps.58 approximation as implemented in the Quantum Espresso package59. We used norm-conserving pseudopotentials and a wavefunction energy cutoff of 45 Ry. The molecular dynamics (MD) calculations were performed at 300 K, using a time step of 2 fs and the Berendsen60 thermostat with a rise time of 10 time steps. The clusters were equilibrated for 25 ps and subsequently data was sampled for 100 ps. Excited states were described by pair excitations61 within constrained DFT, where the Kohn-Sham energy is minimized under the constraint that the occupation of the highest occupied molecular orbital (HOMO) is reduced by 1 e−, compared to the ground state, and the occupation of the lowest energy state directly above the lowest unoccupied molecular orbital (LUMO + 1) is increased by 1 e−. To prevent convergence issues within the electronic loop due to level crossings and concurrent discontinuous changes in the charge density, we implemented a smearing scheme into Quantum Espresso, where a Gaussian smearing is applied individually to the electron and the hole with a smearing of σ = 0.001 Ry. At T = 0 K, phonon eigenfrequencies and eigenvectors are calculated from finite differences. At T = 300 K, phonon densities of states (PDOS) are computed from the MD trajectories using the maximum entropy method (MEM)63, the same numerical setup as above and 4096 poles in the frequency interval from 0 cm−1 to 300 cm−1. The spectra are renormalized so that the integrals ∫dωg(ω) are equal to the number of phonon modes. To calculate g, we approximate the set of discrete phonon frequencies for T = 0 K by Gaussians with a very small but finite width σ = 2 cm−1 according to:We carried out first principles calculations with density functional theory and plane-wave basis sets, within the Perdew-Burke-Ernzerhof (PBE)g is expanded into the same number of Gaussians, albeit with modified positions and widths. All resulting PDOS within the Gaussian basis set have been confirmed to yield the same free energies as before. We then linearly interpolate the widths and positions of the Gaussians as a function of temperature to obtain g.Subsequently. Supplementary InformationPeer Review File


This study tested the hypothesis that autistic traits influence the neuronal habituation that underlies the processing of others’ pain. Based on their autism-spectrum quotient (AQ), two groups of participants were classified according to their autistic traits: High-AQ and Low-AQ groups. Their event-related potentials in response to trains of three identical audio recordings, exhibiting either painful or neutral feelings of others, were compared during three experimental tasks. (1) In a Pain Judgment Task, participants were instructed to focus on pain-related cues in the presented audio recordings. (2) In a Gender Judgment Task, participants were instructed to focus on non-pain-related cues in the presented audio recordings. (3) In a Passive Listening Task, participants were instructed to passively listen. In the High-AQ group, an altered empathic pattern of habituation, indexed by frontal-central P2 responses of the second repeated painful audio recordings, was found during the Passive Listening Task. Nevertheless, both High-AQ and Low-AQ groups exhibited similar patterns of habituation to hearing others’ voices, both neutral and painful, in the Pain Judgment and Gender Judgment Tasks. These results suggest altered empathic neuronal habituation in the passive processing of others’ vocal pain by individuals with autistic traits. Empathy plays an important role in social interactions and daily lives3. By extension, empathy for pain implies the ability of an individual to understand and evaluate the suffering of others4. This enables typically developing individuals to understand the feelings of another individual who is in pain and improve the regulation of appropriate social behaviour5. The perception of others’ pain may automatically elicit corresponding representations in the perceiving individual, so that one could involuntarily match the suffering of others. In addition, if expressed visually7 or vocally8, empathy for others’ pain depends on the level of attention to the stimulus.Empathy is the ability of an individual to comprehend other peoples’ thoughts and feelings as if these thoughts and feelings were experienced by the perceiving individual9. Previous studies have indicated that the quantifiable autistic traits included in the ASD core deficits are continuously distributed in typically developing individuals10. The autism-spectrum quotient (AQ)11 has been used to estimate autistic traits in both ASD individuals and typically developing individuals. ASD individuals were usually identified by extremely high AQ scores compared with the general population12. Empathic impairments in the response to others’ feelings have been suggested as a key symptom of ASD13. Previous studies suggested that typically developing individuals with high AQ scores  exhibit similar behavioural patterns of their empathic responses compared with individuals with ASD15. Compared with individuals with low AQ scores , High-AQ individuals exhibit impaired empathy in implicit tasks, i.e., when their attention is directed away from others’ emotional cues17.Autism spectrum disorder (ASD) is characterised by persistent impairments in social interactions, and by the presentation of restricted and repetitive patterns of behaviour, interests, or activities18. Habituation is pervasive in sensory systems; it refers to changes in neural and behavioural responses that accompany prolonged exposure to an adapting stimulus with repeated features19. Altered habituation in individuals with ASD and autistic traits has been found across diverse domains, including tactile stimulation20, face discrimination21, audio-visual asynchrony22, saccade amplitude23, and auditory cortical adaptation26. For example, a fMRI study used pure tones, which were repeatedly presented at a short and constant inter-stimulus interval (ISI) to individuals with ASD to characterize neural adaption across time. The study found that the post-transient sustained response to the fixed-interval timing repeated tone was stronger in ASD participants than in controls; this reflects reduced auditory adaptation in individuals with ASD18. Previous studies typically used pure tones to study auditory habituation in individuals with ASD and autistic traits. However, whether individuals with autistic traits would exhibit impaired empathic adaptation to repeated emotional auditory stimuli remains an open question.Habituation is a fundamental property of cortical neural responses and has been suggested to be altered in individuals with ASD27 and auditory28 modalities has been documented. In addition, the effects of the modulation of top-down attention on the empathic abilities of individuals with autistic traits have also been studied. In line with previous studies8, our previously published study explored top-down attention for others’ pain, which was manipulated by instructing participants to either focus on pain cues in the stimuli, or to focus on non-pain cues17. The results showed that if individuals with autistic traits were not explicitly instructed to focus on others’ feelings, their empathic responses show impairments17. Furthermore, previous studies indicated that during passive viewing, ASD individuals did not show empathic responses until they were explicitly instructed to do so; this suggests that in these individuals, the spontaneous empathic response may be impaired30. Those studies presented important aspects for the application of experimental paradigms in High-AQ participants. Differences in the top-down attention of task instructions can lead to contrasting empathic responses by these participants.An association between individuals with ASD or autistic traits and their selective impairment with regard to judging others’ pain in the visual8, participants received different instructions for three tasks: (1) Pain Judgment Task: participants were asked to determine the pain level of the presenters of audio recordings; participants had to focus on pain-related cues in this task. (2) Gender Judgment Task: participants were asked to judge the gender of the presenters of audio recordings; participants had to focus on non-pain cues in this task. (3) Passive Listening Task: participants were asked to listen passively without receiving any explicit instruction. This task minimises the above-mentioned influences of instructions, and represents individuals’ spontaneous behaviour and neural responses under natural conditions.The present study attempted to explore whether empathic habituation to others’ pain in individuals with autistic traits is modulated by top-down attention in the auditory modality with event-related potentials (ERPs). Consistent with our previous study30. Based on this, the present study hypothesized that altered empathic neuronal habituation to others’ painful voices in the High-AQ group would only be found in the Passive Listening Task. This represents the impaired empathic habituation of individuals with autistic traits to others’ pain, when they have not been specifically instructed to focus their attention to others (regardless of the presence of pain or non-pain cues). Second, previous studies indicated that the empathic responses of individuals with autistic traits showed impairments in implicit tasks17. Based on this, the present study hypothesized that altered empathic neuronal habituation in the High-AQ group will be present in both the Passive Listening Task and the Gender Judgment Task. In addition, since a previous study found a specific relationship between the magnitude of autistic traits and empathic behavioural responses14, the present study predicted that individuals’ degree of self-reported AQ scores will be associated with their empathic neuronal habituation. Accordingly, individuals with autistic traits show a selective deficit in the empathic neuronal habituation to hearing others’ painful voices.Two hypotheses were tested in the present study. First, previous studies indicated that ASD individuals did not show empathic responses without specific instruction to pay attention to othersNo significant differences in the accuracies (ACCs) and reaction times (RTs) were identified in the Pain Judgment and Gender Judgment Tasks between the High-AQ and Low-AQ groups. Detailed statistical comparisons of behavioural data are summarized in the Supplementary Materials S. Table . Grand aF2, 37 = 4.71, p = 0.015, ηp2 = 0.20). Simple effects analyses indicated that, for High-AQ groups, the effect of “task” was found in response to neutral voices . However, this effect did not pass FDR correction. Also, S1_N1 amplitudes were not different among experimental tasks in other conditions .As shown in Figs. F2, 37 = 5.02, p = 0.012, ηp2 = 0.21). Post hoc comparisons showed that S2_N1 amplitudes in the Passive Listening Task were significantly higher than in the Gender Judgment Task . However, no significant differences were observed between the Pain Judgment Task and the other two tasks . The S2_N1 amplitude was significantly modulated by the interactions of “group × task” , “group × stimulation” , and “group × task × stimulation” . Simple effects analyses indicated that, with regard to painful voices in the Passive Listening Task, S2_N1 amplitudes were significantly higher for Low-AQ groups than for High-AQ groups , which passes FDR correction. S2_N1 amplitudes were not different between groups in other conditions . In addition, the group differences of differential ERP amplitudes between painful and neutral voices  were significant in the Passive Listening Task (p = 0.001), but neither in the Pain Judgment Task (p = 0.160), nor the Gender Judgment Task (p = 0.392) . Post hoc comparisons showed that S3_N1 amplitudes in the Gender Judgment Task (−3.48 ± 0.75 μV) were significantly higher than those in both the Passive Listening Task  and the Pain Judgment Task . No significant differences were observed between the Pain Judgment Task and the Passive Listening Task (p = 0.821).The frontal-central S3_N1 amplitude was only significantly modulated by the main effect of “task” . Post hoc comparisons showed that the S1_P2 amplitudes in the Passive Listening Task (2.71 ± 0.42 μV) were significantly smaller than those in the Pain Judgment Task . In addition, S1_P2 amplitudes in response to painful voices in the Passive Listening Task (2.68 ± 3.02 μV) were smaller than those in the Pain Judgment Task (3.99 ± 3.51 μV)  .The S1_P2 amplitude was only significantly modulated by the main effect of “task”  and “stimulation” . Post hoc comparisons showed that the S2_P2 waves in the Gender Judgment Task (− 3.24 ± 0.64 μV) were more negative than those in both the Passive Listening Task  and the Pain Judgment Task . However, no significant differences were observed between the Pain Judgment Task and the Passive Listening Task (p = 0.370). Painful voices elicited smaller S2_P2 amplitudes than neutral voices (− 2.92 ± 0.60 μV vs. − 1.71 ± 0.54 μV). The S2_P2 amplitude was significantly modulated by the interaction of “group × task × stimulation” . Simple effects analyses indicated that, when reacting to painful voices in the Passive Listening Task, S2_P2 amplitudes were significantly smaller for Low-AQ groups than for High-AQ groups , which passed FDR correction. The S2_P2 amplitudes were not different between groups in other conditions . In addition, group differences of differential ERP amplitudes between painful and neutral voices  were significant in the Passive Listening Task (p = 0.001), but neither in the Pain Judgment Task (p = 0.108), nor the Gender Judgment Task (p = 0.324) . Post hoc comparisons showed that the S3_P2 amplitudes in the Gender Judgment Task (-4.10 ± 0.78 μV) were significantly smaller than those in the Pain Judgment Task . No significant differences were observed between the Passive Listening Task (− 2.33 ± 0.76 μV) and the other two tasks .The S3_P2 amplitude was only significantly modulated by the main effect of “task”  and “stimulation” . Post hoc comparisons showed that both the S1_LNC and S2_LNC waves in the Gender Judgment Task  were more negative than those in both the Passive Listening Task  and the Pain Judgment Task . No significant differences were observed between the Pain Judgment Task and the Passive Listening Task . Painful voices elicited more positive waves than neutral voices . S1_LNC and S2_LNC amplitudes were modulated by the interaction of “group × task × stimulation” . Simple effects analyses indicated that, when reacting to painful voices in the Passive Listening Task, both the S1_LNC and S2_LNC amplitudes were significantly larger for Low-AQ groups than for High-AQ groups . The S1_LNC and S2_LNC amplitudes were not different between groups in the other conditions . In addition, for the S2_LNC component, the group differences of the differential ERP amplitudes between painful and neutral voices  were significant in the Passive Listening Task (p = 0.005), but neither in the Pain Judgment Task (p = 0.179), nor the Gender Judgment Task (p = 0.256) . Post hoc comparisons showed that the S3_LNC amplitudes in the Gender Judgment Task (− 7.23 ± 1.01 μV) were significantly larger than those in both the Pain Judgment Task  and the Passive Listening Task . No significant differences were observed between the Pain Judgment Task and the Passive Listening Task (p = 0.840).The frontal-central S3_LNC amplitude was only significantly modulated by the main effect of “task” . Simple effects analyses indicated that, with regard to the differences between painful and neutral voices in the Passive Listening Task, the amplitudes of S2_P2_habituation were significantly larger for High-AQ groups than for Low-AQ groups , which passed FDR correction. In the Pain Judgement Task, the amplitudes of S2_P2_habituation were not different between groups  and the same was found for the Gender Judgement Task . No other main effect or interaction was found .The amplitudes of S2_P2_habituation were significantly modulated by the “group × task” interaction  and S2_P2_habituation  in the Passive Listening Task were significantly correlated with AQ scores. No other reliable correlation was found between AQ scores and indexes of empathic neuronal habituation .To investigate whether the indexes of empathic neuronal habituation correlated with AQ scores, the Pearson Correlation between them was calculated. Amplitudes of S2_N1_habituation  with short and constant ISI in both High-AQ and Low-AQ groups. The indexes for empathic neuronal habituation were analysed in each condition. The results showed that the ERP responses to the first stimulus (S1) were equivalent between groups. However, in the Passive Listening Task, the ERP amplitudes in response to painful voices in the second (S2) and third (S3) stimuli of the triplet  were lower in the High-AQ group than in the Low-AQ group. More importantly, in the Passive Listening Task, the amplitudes of S2_P2_habituation were only significantly higher for High-AQ groups rather than for Low-AQ groups. This reflects the altered habituation of neuronal empathic responses to others’ vocal pain, when individuals with autistic traits have not been instructed to specifically focus their attention to others.The present study investigated the influence of autistic traits on the top-down attention-induced modulation of the habituation to others’ vocalizations of pain. In line with previous results8, in the present study, the P2 amplitudes of S1 in response to the painful voices in the Passive Listening Task were smaller than in the Pain Judgment Task. Since the P2 response is relevant to the emotional quality of the audio recordings31, and since our previous studies showed that the P2 amplitudes related to painful voices were significantly and positively correlated with pain intensity ratings17, P2 amplitudes to painful voices at least partly reflected cognitive empathy for others’ vocal pain8. This suggests that, compared with the Passive Listening Task, when focusing on others’ vocal pain in the Pain Judgement Task, participants showed more empathic neuronal responses to others’ pain. Consequently, top-down attention could modulate individuals’ empathic responses to others’ vocal pain.Consistent with the results of a previous study35, the present study showed that stimulus repetition at short and constant ISI significantly decreased the magnitudes of S2 and S3 stimuli , both groups exhibited comparable auditory habituation.Consistent with previous studies14, amplitudes of S2_P2_habituation in the Passive Listening Task were significantly positively correlated with AQ scores. The higher the AQ scores of individuals, the larger the amplitudes of this index of empathic neuronal habituation, suggesting that S2_P2_habituation was sensitive to the magnitude of autistic traits. In summary, these results indicate that S2_P2_habituation in the Passive Listening Task may be a suitable index to represent the empathic neuronal habituation to others’ vocal pain in individuals with autistic traits.Interestingly, analyses of group differences only found significant differences in the indexes of empathic neuronal habituation to others’ vocal pain between High-AQ and Low-AQ groups in the S2_P2_habituation of the Passive Listening Task. In addition, in accordance with a previous study37. Without directly asking individuals who are involved in an explicitly empathic task, e.g., to give a verbal report (as applied in the Pain Judgment Task and Gender Judgment Task), the Passive Listening Task requires a more indirect assessment and implicit empathic processes38. The empathic competences of individuals with ASD and autistic traits have often been measured with regard to isolated and specific skillsets under explicit laboratory conditions37. For example, a study might focus on participants’ attention to emotional stimuli on a computer screen or to an audio recording, as used in the Pain Judgment Task and Gender Judgment Task in the present study. However, it remains highly debatable whether such an assessment can predict the participant’s spontaneous behaviour under natural conditions. A relevant study suggested that the cognitive assessment of others’ emotions by individuals with ASD and autistic traits remains basically intact39. Their impaired empathic affective sharing responses may be due to shortcomings of the automatic sensitivity to others’ emotions or their intrinsic motivation to perceive others’ feelings41. Similar empathic neuronal responses between High-AQ and Low-AQ groups were found in the Pain Judgment Task and the Gender Judgment Task. In the present study, the Passive Listening Task more likely reflects day-to-day life. Participants’ responses were not based on isolated explicit requests in structured situations, which is generally the result of empirical research42. Altered empathic neural habituation of High-AQ groups was only observed in the Passive Listening Task, which may explain the informants’ reports of spontaneous empathic behaviour in unstructured situations. This method is generally relied upon by diagnostic assessment procedures37.Altered habituation of empathic responses to others’ pain vocalisations was only found in the Passive Listening Task. This supports the first hypothesis that impaired empathic habituation can be found in individuals with autistic traits, if they have not been specifically instructed to focus their attention to others’ painful voices (regardless of whether pain or non-pain cues were presented). The effects of the modulation of top-down attention on emphatic responses were previously observed in individuals with ASD43. This theory holds that autistic individuals may in general exhibit enhanced perception, attention, and memory capabilities, which may cause the world to become too intense and even aversive, causing many of the autistic symptoms, such as social interaction44 and perception45 disorders. Therefore, the social impairment of individuals with autistic traits may not be due to deficits in their ability to process others’ emotions and feelings. Rather, this social impairment is more likely the result of repeated social stimuli that are overly intense and excessively processed with altered habituation43.In summary, the present study did not find global impairment of empathic habituation to others’ pain in individuals with autistic traits. In contrast, these individuals exhibited altered habituation to more intense, negative, and highly intense stimuli, i.e., painful voices in the present study, but not to less intense neutral voices. In addition, altered neural responses were found in the second and third repeated stimuli, but not in the first stimuli. This may be because the repetition of the painful voices is more intense than the single stimuli. Furthermore, this impairment was only observed when participants with autistic traits were passively listening. This finding may be because when the participants were not instructed to focus on the stimuli, the highly intense, repeated, and painful voices may become more disturbing. Thus, the pattern may be explained by the “Intense World Theory”Despite these potential implications, several limitations of the present study should also be noted. First, this study used tracks of three identical voices with constant and short ISI to evaluate participants’ empathic habituation. Further investigations should use dynamic videos to evaluate the individual empathic process, since these may be more similar to experiences of everyday life. Second, although the influence of autistic traits on the top-down attention modulation of empathic responses was assessed under experimental settings, whether and how these responses relate to real-world empathy requires further investigation. Third, in the Passive Listening Task, since filler trials were not integrated to assess whether participants focused sufficiently over the whole task, further investigations should evaluate the participants’ attentional process by integrating filler trials.In summary, this study investigated the influence of autistic traits on top-down attention-induced modulation with regard to the empathic neural habituation to others’ vocalization of pain. ERPs were used to measure the habituation that was induced by the repetition of three identical audio recordings (S1-S2-S3) in both High-AQ and Low-AQ groups. Compared with Low-AQ groups, the amplitudes of S2_P2_habituation were only significantly larger in High-AQ groups in the Passive Listening Task. This reflects the altered neural empathic habituation to others’ audio pain when High-AQ participants have not been instructed to focus their attention to others. These results suggest that individuals with autistic traits are affected by altered habituation of implicit neural empathic responses to others’ audible pain.46. This questionnaire was used to estimate their autistic traits. Then, a subset of participants (those exhibiting the top 10% and bottom 10% of AQ scores)17 were randomly selected and divided into High-AQ (n = 20) and Low-AQ (n = 20) groups, respectively. The demographic characteristics of the participants in the High-AQ and Low-AQ groups are summarized in Table A total of 2,083 university students at the Chongqing Normal University, aged 18–23  were recruited to complete the Mandarin Version of the AQ questionnaire47. All audio recordings were edited to last 700 ms, with a mean intensity of 70 dB48.A total of 20 audio recordings of interjections (/ɑ/), spoken in either a painful (10 recordings) or neutral (10 recordings) prosody, were selected from the Montreal Affective Voices database. This database was recorded by 10 actors 17, top-down attention for another individual’s pain was manipulated by instructing the participants to either pay attention to pain cues or non-pain cues, or by passively listening to the provided audio recordings. They were instructed to participate in three experimental tasks: (1) a Pain Judgment Task, (2) a Gender Judgment Task, and (3) a Passive Listening Task. The order in which these three tasks were presented was counterbalanced across participants and the order of stimulus presentation was also randomized. Stimulus presentation was controlled using E-Prime (3.0) software.The participants were seated in a quiet room with an ambient temperature of approximately 20 °C. In line with our previous studies33, each recorded section consisted of three identical stimuli . Each voice in the triplet lasted for 700 ms, with an interval of 500 ms. Following the stimulus triplet, participants were instructed to respond as accurately and quickly as possible to a sound signal  by pressing a specific key (either “1” or “2”). The Pain Judgment Task consisted of two blocks, with 70 stimulus recordings  in each block. The inter-trial interval was 3–4 s. Prior to the formal task, each participant took part in a training session to become familiarized with the process.In the Pain Judgment Task  data were recorded from 64 scalp sites using tin electrodes mounted on an elastic cap . The electrode at the right mastoid was used as recording reference; that on the medial frontal aspect was used as ground electrode. Vertical electrooculograms (EOGs) were recorded both supra- and infraorbitally at the left eye. Horizontal EOGs were recorded as the left versus right orbital rim. All electrode impedances remained below 5 kΩ.In line with our previous study49. Continuous EEG signals were band-passed filtered (0.1–40 Hz) and segmented using a 4,100 ms time window relative to the onset of the first stimulus in the triplet (S1), with 500 ms pre-stimulus and 3,600 ms post-stimulus. All EEG epochs were baseline-corrected using the pre-stimulus interval. In addition, the EEG epochs were also visually inspected, and epochs contaminated by gross movements were removed. The removed EEG epochs constituted 7 ± 3.5% of the total number of epochs. EOG artefacts were corrected via the independent component analysis (ICA) algorithm50.The EEG data were pre-processed and analysed via MATLAB R2014a  and the EEGLAB toolbox48, the dominant ERP components involved in hearing others’ painful and neutral voices were identified, including N1, P2, and the late negative complex (LNC) elicited by each voice. Specifically, N1 and P2 waves were respectively defined as the most negative and positive deflections, respectively, at 100–300 ms after voice stimulus onset, with maximum distribution at the frontal-central electrodes. The LNC wave was the long-lasting negative and frontal-central distributed deflections within latency intervals of 400–700 ms after voice stimulus. As a result, for each participant and audio recording, N1 and P2 amplitudes were measured at the frontal-central electrodes  and calculated as the average ERP amplitudes within the latency interval ± 10 ms relative to the corresponding peak latency; LNC were measured at the frontal-central electrodes  and at latency intervals of 300–700 ms after the onset of the audio recording.The EEG epochs elicited by painful and neutral voice recordings during the three experimental tasks were averaged and time-locked to the onset of the triplet of S1–S2–S3, yielding six averaged waveforms. Single-participant waveform averages were further averaged to obtain group-level waveforms, and group-level scalp topographies at corresponding peak latencies were computed by spline interpolation. Based on the topographical distribution of grand averaged ERP activity and previous studiesBehavioural data, including ACCs and RTs, were compared. This was done using a three-way mixed design analysis of variance (ANOVA), with within-participant factors of “stimulation”  and “task” , as well as the between-participants factor of “group” (High-AQ vs. Low-AQ).p values were corrected using a false discovery rate (FDR) procedure51. In addition, to explore the effects of the modulation of top-down attention on the empathic responses between groups in response to painful voices, additional data analysis of the differences between Passive Listening Task and Pain Judgment Task in response to painful voices was conducted using Paired-Samples t Tests  for S1–S2–S3 stimuli were compared via a three-way ANOVA with within-participant factors of “stimulation”  and “task” , as well as the between-participants factor of “group” (High-AQ vs. Low-AQ). When a significant interaction effect was found, post hoc pairwise comparisons between High-AQ and Low-AQ groups were performed. The degrees of freedom for F-ratios were corrected according to the Greenhouse–Geisser method. To account for the multiple comparison problem, the , and LNCTo explore the empathic neural habituation effect to others’ vocal pain, indexes for empathic neural habituation were defined by computing the difference between the ERP amplitudes elicited by S2 or S3 and those elicited by S1 . For example, S2_index_habituation for the N1 component was calculated as S2_N1_habituation = S2_N1–S1_N1; S3_index_habituation for P2 component was calculated as S3_P2_habituation = S3_P2–S1_P2. For indexes of empathic neural habituation, the amplitudes of the differences between painful and neutral stimuli  were compared via two-way ANOVA with the within-participant factors of “task”  and the between-participants factor of “group” (High-AQ vs. Low-AQ). In addition, to investigate the relationship between the indexes of empathic neural habituation that correlate with the AQ scores, the Pearson Correlation was calculated between them.This research was approved by the Chongqing Normal University research ethics committee. All participants signed informed consent forms after receiving a complete description of the study. The ethics committee approved this consent procedure.Supplementary information


Specifically, we used a 63 cm-long gypsum stalactite from Sima Blanca Cave to reconstruct the climate history of SE Spain from ~ 800 BCE to ~ 800 CE. The gypsum stalactite indicates wet conditions in the cave and humid climate from ~ 200 BCE to 100 CE, at the time of the Roman Empire apogee in Hispania. From ~ 100 CE to ~ 600 CE, evaporation in the cave increased in response to regional aridification that peaked at ~ 500–600 CE, roughly coinciding with the transition between the Iberian Roman Humid Period and the Migration Period. Our record agrees with most Mediterranean and Iberian paleoclimate archives, demonstrating that stable isotopes of GHW in subaerial gypsum speleothems are a useful tool for paleoclimate reconstructions.Carbonate cave deposits (speleothems) have been used widely for paleoclimate reconstructions; however, few studies have examined the utility of other speleothem-forming minerals for this purpose. Here we demonstrate for the first time that stable isotopes (δ In addition to calcite and aragonite, over 300 other minerals have been reported from caves3. After carbonates, sulfates are the second most important group with gypsum (CaSO4·2H2O) being the most common sulfate mineral in caves5.Carbonate speleothems  are important archives for Quaternary climate reconstructions in terrestrial environments2+ and SO42− to cave dripwater and subsequent in-cave evaporation leads to a solution that is saturated with respect to gypsum5. Gypsum speleothem formation is mostly controlled by evaporation, unlike carbonate speleothems that largely form because of CO2 degassing. Although the occurrence of subaerial gypsum speleothems is limited compared to carbonate speleothems3, gypsum stalactites, stalagmites, flowstones, coralloids and frostwork can be found in a number of caves in arid and semiarid regions7.Subaerial gypsum speleothems can form during the evaporation of calcium-sulfate-rich solutions in subterranean environments. The dissolution of gypsum host-rock (e.g. Messinian marine gypsum) supplies Ca17O, δ18O and δD, and derived parameters d-excess and 17Oexcess; see “5. The fractionation factor between GHW and the mother solution (dripwater) is relatively insensitive to temperature9. This contrasts with other isotopic proxies in speleothems (e.g. δ18O in carbonates) that can be influenced by temperature and kinetic effects. Our recent ability to measure all the stable isotopes  of GHW10 is advantageous for using GHW as a paleoclimate archive. Indeed, recent investigations have utilized triple oxygen and hydrogen isotopes of GHW from marine and lacustrine gypsum deposits to reconstruct the climate of the past15.The isotopic composition of evaporated dripwaters  from Sima Blanca Cave (402 m a.s.l)  of evaporated cave dripwater from ~ 2.800 to ~ 1.200 years BP. This period spans the Iron Age (800–650 BCE), the Iberian Roman Humid Period  and the Migration Period (476–800 CE). Throughout this study, “years BP” refers to years before present, where present is 1950 of the Common Era (CE).The Sorbas Basin (SE Spain) is a type locality for gypsum karst and has a well-developed system of caves with varying degrees of decoration.l) Fig.  online t16. Among the different ancient civilizations that the occupied Andalusia, the Roman Empire (~ 200 BCE to ~ 400 CE) left a rich cultural and architectural heritage in the Roman Iberian province of Hispania Ulterior (197 BCE to 27 CE), later called Baetica (27–411 CE)17. Most archaeological and historical reconstructions agree that the abandonment of the Iberian Peninsula by the Romans was mainly caused by a generalized sociopolitical collapse, together with the Barbarian invasions that contributed to the fall of the whole Roman Empire18. However, various paleoclimate reconstructions also suggest that climate change may have played a role, including the occupation and the abandonment of the Roman Iberian province of Baetica16. Independent written and archaeological evidence consistently support variable climate conditions during the period of the Roman Empire’s expansion and final demise.Previous studies have suggested that the fate of various civilizations occupying the Andalusian lowlands (southern Iberia Peninsula) may have been affected by climatic change, which impacted the availability of freshwater and agricultureYet, terrestrial paleoclimate reconstructions from the region are scarce. We aim to establish if the stable isotope ratios of hydration water in gypsum speleothems can be used as a paleoclimate proxy to reconstruct past changes in wetness/dryness of SE Iberia between 800 BCE and 800 CE. The Sima Blanca stalactite grew during the period of Roman occupation, and the paleoclimate history inferred from its GHW is compared to other Mediterranean and Iberian paleoclimate archives to evaluate the reliability of gypsum speleothems as a recorder of past climate conditions Fig. .Details of sampling and labeling are given in the “19. The 238U content in the dated gypsum samples ranges from 94 to 178 ppb. Low U content and thus extremely low 230Th concentration precluded obtaining an age for sample SBL-33. As 230Th/232Th is < 20 (5.1–14), a correction for 230Th contamination was needed to obtain accurate ages  in the SBL stalactite is probably related to clay minerals from the Messinian host-rock (i.e. gypsum-marl beds) or detrital contributions from the soil above the cave. Low U concentrations and high detrital Th of gypsum speleothem hinder extremely accurate and precise dating of gypsum speleothems in the Sorbas basin, but the errors are sufficiently low (± 129 to ± 334 years) to permit comparison with other regional paleoclimate records.The U and Th contents in SBL stalactite are relatively low, as in most gypsum speleothems analysed previouslyges see “”. The 2321 is anchored by four U-Th ages  and thus can be assumed to be constant. For instance, the use of temperatures that are 10 °C higher or lower changes the δ18O values by only ~  ± 0.05‰ and δD by ~  ± 1‰, which is not very significant relative to the analytical precision of our method.The δ17O, δ18O and δD of the speleothem-forming water show the lowest values  at ~ 2,100 years BP, whereas the highest values  occur at ~ 1,400 years BP  that is considerably lower than that of the Local Meteoric Water Line (LMWL) , decreasing evaporation in the cave and thus suppressing gypsum precipitation. Consequently, as evaporative conditions are more likely to occur during winter, we interpret the isotopic record of the SBL stalactite as reflecting winter evaporative conditions in the cave.Previous studies on subterranean microclimate parameters in the gypsum karst of Sorbas Basin  concluded that the precipitation of gypsum speleothems is favoured during the winter dry season (January–March), when relative humidity in the upper cave passages is less than 95% and occasionally below 60%22. Water condenses on the cave ceiling, dissolving Messinian gypsum host-rock and the water becomes saturated with respect to gypsum. The saturated water then migrates by gravity along the surface of the stalactite, mixing along its path with seepage water, and gypsum deposition occurs because of evaporation. The relative contribution of the condensation water source to the dripwater was estimated to be ~ 40% in the nearby Covadura Cave system. The intensity of this condensation process depends on the difference between external and internal cave temperatures and on the degree of cave ventilation22. Sima Blanca cave is a shallow subterranean system (~ 10 m deep) and its temperature is expected to equilibrate rapidly with the external atmospheric temperature. This has been observed in the passages of Covadura Cave system , where the equilibration time is < 2 months23. As a result, we do not expect the condensation to seepage water ratio to change significantly either on an inter-annual basis or during the growth of the SBL stalactite. In addition, the modern mean isotopic composition of dripwater and condensation water in these caves differ by only ~ 1‰ for δ18O and ~ 5.5‰ for δD, whereas their d-excess and 17Oexcess are indistinguishable within error5. This reinforces the idea that long-term changes in the condensation to seepage water ratio did not significantly alter the isotopic composition of the SBL stalactite, but rather isotopic changes mainly reflect the degree of evaporation within the cave.In addition to infiltration water, condensation of atmospheric water vapour has been found to be an important source of water for gypsum speleothem formation during summer and autumn17O, δ18O and δD and derived parameters d-excess and 17Oexcess is evaporation5. The absence of stalagmites in Sima Blanca suggests that most dripwater is evaporated from the speleothems on the ceiling. We observe that the values of d-excess and 17Oexcess versus δ18O describe an evaporation trend   Fig. . In gene. 5 Fig. . Higher 26. Convective rainfall events from the Mediterranean are isotopically enriched, and prevail during summer and autumn and during warm climatic periods. In contrast, rainfall with lower isotopic values are transported along Atlantic storm tracks, which dominate during winter and during colder climatic periods26 The mean δ18O values of modern rainfall from the Mediterranean have been found to be up to 3‰ higher in this region than rainfall events from Atlantic fronts27. Also, the d-excess values in rainfall from Mediterranean convective events are normally higher than in precipitation from the Atlantic moisture source28. Changes in the contributions of the Mediterranean and Atlantic moisture sources to the total hydrological budget in SE Iberia have been proposed previously to explain the δD variability of n-alkanes in sediment profiles of alpine lake of the Sierra Nevada26. This mechanism could have partially influenced the isotopic composition dripwater in Sima Blanca Cave; however, the fact that the δ18O–δD values of the speleothem-forming water are linearly correlated, with a slope much lower than that of the Local Meteoric Water Line  that is positively correlated to normalized relative humidity at the oceanic moisture source29. Water evaporation under low relative humidity conditions at the moisture source generates water vapour (and rainwaters) with greater 17Oexcess values30. This contrasts with the behaviour of 17Oexcess in evaporated waters that tends to be lower when evaporation occurs under low relative humidity conditions15. Therefore, the 17Oexcess record of the SBL stalactite may be partially controlled by the long-term variability in the triple oxygen isotope composition of rainwater/infiltration water in the Sorbas area and the effects on 17Oexcess of dripwater evaporation in the cave varying relative humidity conditions. Other potential mechanism may include changes in the main moisture source region (i.e. Mediterranean vs Atlantic source) or changes in the contributions of a non-rainfall water source (e.g. fogs) to cave dripwater.No specific studies have been conducted to measure the 17O, δ18O and δD values derived from drier conditions and potentially from higher contributions of rainfall from the Mediterranean moisture source; lower δ17O, δ18O and δD, indicate wetter periods and may also suggest a greater influence of the Atlantic moisture source to the precipitation in this region.In summary, the SBL stalactite isotope record is interpreted here as a function of infiltration/evaporation ratio in the cave, which is affected by rainfall amount in SE Iberia and humidity in Sima Blanca Cave. Also, varying contributions of the Atlantic and Mediterranean moisture sources to rainfall in this region could have influenced the isotopic signal of dripwater in the cave. Higher δ17Oexcess in GHW of gypsum speleothems in Sima Blanca Cave is more complicated, and there is very little information available for 17Oexcess variability of modern rainfall in this region. Therefore, interpretation of the 17Oexcess record of SBL remains speculative.Lower d-excess values in the SBL record indicate drier climate, although the signal may have been attenuated by higher d-excess of rainfall in response to greater contributions of Mediterranean convective precipitation events during dry periods. Higher d-excess values of GHW suggest wetter climatic conditions, with possible attenuation of the signal because of greater influence of the Atlantic rain events, which have lower d-excess values. The mechanisms controlling 34, several alpine lakes in Sierra Nevada39 and sediment records in the Alboran Sea33  there are no age reversals in the U/Th dates.The climatic changes inferred from the oxygen and hydrogen isotope ratios in GHW of the SBL stalactite are consistent with other nearby paleoclimate records from the region Fig. , includia33 Fig. . Several32, may have prevented stalactite formation. Likewise, low concentration of Quercus pollen in sediments of alpine lakes of Sierra Nevada are indicative of dry conditions during the Late Iron Age38  of speleothem-forming water and relatively low d-excess (− 22‰) at 800 BCE compared to the mean value of the entire record  indicates generally drier climate prevailed at this time. Also, greater contribution of the Mediterranean vapor source to rainfall in this region could result in higher isotopic values of dripwater in the cave during this period.The SBL stalactite started growing at ~ 800 BCE. Dry conditions in southern Iberia prior to 800 BCE, as evidenced by a lower-than-average level of Lake Zoñare38 Fig. . The rel17O, δ18O and δD values of evaporated paleo-dripwater decreased from 800 until ~ 500 BCE by about 0.5, 1.1 and 2.9‰, respectively, while d-excess increased by 5.9‰. This period includes the onset of the Iberian Roman Humid Period (IRHP), as inferred from the sediments of Lake Zoñar (650–510 BCE)33. A sharp decrease in δ17O, δ18O and δD values between 400 and 300 BCE result in the lowest isotopic values observed in the entire record. This abrupt change is accompanied by an increase in d-excess by ~ 8‰, until − 14‰, which is the highest d-excess value recorded in the SBL stalactite, indicating a trend toward wetter conditions. This shift in the isotope records and inferred wetter conditions coincide with an increase in Rb/Al recorded in the Lake Zoñar sediments at 400 BCE, as a result of enhanced runoff because of increased rainfall33. In addition, the concentration of Quercus pollen in Laguna de la Mula in the Sierra Nevada started to increase from 350 BCE as a result of enhanced water availability38.Consistent with a trend towards wetter conditions, δ17O, δ18O, δD and d-excess values stabilized from 300 to 100 BCE at ~ 0.3‰, 0.6‰, − 8‰ and − 13‰, respectively, which are among the lowest values of the record  and is consistent with increased input of fluvial sediment to the Alboran Sea at that time33. Also, a large range of paleoclimatic records support these wet conditions in southern Iberia at ~ 300–200 BCE 32. The SBL record and other lake proxies in the region suggest this change may have been more abrupt.The δord Fig. , suggestBCE Fig.  includin39 and recurrent desiccation of other lakes in south Iberia41. The driest stage of the SBL record occurred at ~ 500 CE, when δ17O, δ18O, δD and d-excess of the evaporated paleo-dripwater reach their highest values . An increase in the frequency and intensity of convective rainfall events from the Mediterranean could have contributed to the relatively high δ17O, δ18O, δD values recorded by the speleothem during this period.Following this wet period, the SBL data support an aridification trend from ~ 100 BCE to 600 CE. This is indicated by the decrease in d-excess (− 10‰) during this period. The drying inferred from Sima Blanca cave agrees well with other Iberian terrestrial and marine records Fig.  that docCichorioideae herbs and by the decline in the water levels in alpine lakes in the area39. Additionally, a progressive drying around 700 CE has been observed in Alboran Sea sediments. The SBL stalactite stopped growing at ~ 800 CE probably because of a reduction in water infiltration to the cave. This coincided with the last stages of the Visigoth occupation of Hispania (~ 800 CE), when generally dry conditions prevailed in Iberia42.The latest part of the SBL record (from ~ 600 to ~ 800 CE) indicates conditions slightly wetter than during the previous 300 years, but drier than the period from 200 to 100 BCE. Dry conditions during the early stages of the Migration Period are indicated by a prominent decrease in Mediterranean forest in SE Iberian mountains, by an increase in 43. The SBL stalactite record between ~ 800 BCE and ~ 800 CE also generally correlates with changes in the NAO (North Atlantic Oscillation) index44 and atmospheric radiocarbon production45. It is therefore possible that the aridification trend in SE Iberia may have been related to increased solar activity and NAO+ conditions . Additional monitoring of modern conditions, including measurement of 17Oexcess in dripwater and rainfall in the region may help to better understand the climate signal recorded by the SBL stalactite.Previous studies in Andalusia have suggested a possible link between varve thickness and geochemical proxies in several lakes of lowlands and alpine areas and the North Atlantic Oscillation (NAO) and solar variabilityons Fig. . While tThe wettest conditions inferred from the SBL stalactite Fig.  occurred48, as well as significant landscape modification45 during this period. Lead pollution from Roman mining in Iberia is recorded by lake sediment cores in Europe49 and ice cores in Greenland50, the Russian Arctic51 and the Alps52. Increased charcoal abundance in several lake sediment cores suggest intense deforestation and biomass burning during the early and middle-IRHP53 51 51 Fig. .60. Indeed, exceptional climate variability in Europe from ~ 250 to 550 CE is evidenced by tree-ring records, including periods of severe and prolonged droughts61. This was a time of increased aridification of SE Iberia. Drier winters, as suggested by the SBL record, probably resulted in crop failure and more extreme weather events that led to agricultural instability during the abandonment of Iberia by the Romans17.The Imperial Crisis has been attributed to a combination of migrations into the Roman territory, Barbarian invasions and civil wars, peasant rebellions, political instability, debasement of currency, and economic depression. Natural disasters, such as plague  and/or increased climate variability, may have contributed to the fall of the Roman Empire61. These events coincided with decreasing total solar irradiance in the Northern Hemisphere62 and an event of ice-rafting in the subpolar North Atlantic 63.The driest conditions inferred from the SBL stalactite occur at the transition between the IRHP and the Migration Period, at 500–600 CE. Cold and dry conditions occurred in the northern hemisphere during the Late Antique Little Ice Age (between 536 and 660 CE) and had an important impact on the transformation of ancient civilizations. Written sources pointing to significant veiling of solar radiation in 536 and 537 CE have been attributed to a powerful volcanic eruption that resulted in crop failures in different areas of the Roman Empire16O, 17O, 18O) and hydrogen  stable isotopes of cave dripwaters as a proxy for evaporation. We suggest that gypsum speleothems in arid or semiarid regions constitute a valuable and unexploited archive of paleoclimate information.In summary, we demonstrate for the first time that stable isotopes of hydration water in gypsum speleothems can be used as a proxy for paleo-humidity/aridity. This novel approach offers the possibility of estimating all the oxygen  to 1.2 cm at the apex . This indicates that the SBL was fed by a single infiltration-discharge point in the ceiling and preferentially grew in length, with minor lateral contributions. The structure of the SBL stalactite shows an inner feeding channel, ~ 0.5 cm wide, that conducted water from the feeding point to the stalactite’s tip, where drops of water evaporated to form gypsum. This conduit is similar to that found in carbonate stalactites. The SBL’s inner channel is partially filled with gypsum that probably precipitated during the last stage of formation of the speleothem before growth stopped, related to a reduction in water infiltration to the cave or a change in the water path in the epikarst. This inner part was avoided for sampling  was added slowly until all the gypsum sample was completely dissolved. After the dissolution of the gypsum, ~ 7 mg of iron carrier (FeCl3) was added and the solution was left on the stirring plate overnight for spike sample equilibration. The uranium and thorium were separated from the bulk of the material with Fe(OH)3 precipitation using NH4OH. The precipitates were washed with MilliQ water and then dissolved in 6 N HCl. The U-Th separation was conducted using AG1X8 anionic resin bed, following the method in Ref.64. The U and Th fractions were deposited on Re filament between two layers of graphite and measured using a Triton Plus mass spectrometer (TIMS) equipped with an RPQ 65. Mass fractionation for U was corrected by the double spike 236U/233U (1.1322), while mass fractionation for Th was considered negligible with respect to analytical error65. The overall analytical reproducibility, as estimated from replicate measurements of standards, is usually better than 0.5% for U concentration and 234U/238U ratios, and ranges from 0.5 to 1% for 230Th/234U ratios (2σ error range). The presence of non-authigenic 232Th is indicated by 230Th/232Th < 20 and implies the need for correction. We use a mathematical correction in which the U–Th isotopic composition of the detrital contamination is arbitrary estimated, in a manner resembling the approach in Ref.65. 232Th uses a correction and assumed a typical crustal Th/U ratio of 3.5, with 234U/238U and 230Th/238U activity ratios near secular equilibrium. In our model, we used 232Th/238U = 1.21 ± 50%, 234U/238U = 1 ± 10% and 230Th/238U = 1 ± 10%. Corrected 230Th/238U and 234U/238U activity ratios were then used to calculate the corrected ages . Powdered gypsum subsample (3–10 g) were weighed and transferred to 250 mL Teflon beakers, in which weighed amounts of a mixed spike in vacuo. We used a bespoke offline extraction system consisting of six vacuum lines contained within a modified gas chromatography oven, following the methods in Ref.10. Oxygen (δ18O and δ17O) and hydrogen (δD) isotopes of GHW were measured simultaneously by cavity ring down spectroscopy (CRDS) in the Godwin Laboratory at the University of Cambridge (United Kingdom) using a L2140-i Picarro water isotope analyzer24. The results were normalized to the V-SMOW-SLAP scale by analyzing internal standards before and after each set of 12–15 samples. Four internal water standards  were calibrated against V-SMOW and SLAP, using δ17O of 0.0‰ and − 29.69865‰, respectively, and δ18O of 0.0‰ and − 55.5‰, respectively67. This standardization considers 17Oexcess = 0 for both international standards, where 17Oexcess = ln  − 0.528 × ln 68. δD was calibrated against V-SMOW, GISP and SLAP. All isotopic deviations are reported in parts per thousand (‰) relative to V-SMOW and 17Oexcess values are given in per meg units (0.001‰). External error (1SD) of the method was ± 0.05‰ for δ17O, ± 0.1‰ for δ18O, ± 0.7‰ for δD, ± 0.8‰ for d-excess (δD-8* δ18O) and ± 11 per meg (± 0.011‰) for 17Oexcess, as estimated by repeated analysis (n = 5) of an analytical grade standard, extracted together with five samples in each run of the extraction apparatus10.Powdered gypsum samples were dried in an oven overnight at 45 °C. GHW was extracted by slowly heating each sample (~ 150 mg) to 400 °C, Supplementary Information.


Gender-affirming hormone therapy (GHT) is utilized by people who are transgender to align their secondary sex characteristics with their gender identity. Data relating to cardiovascular outcomes in this population are limited. We aimed to review the impact of GHT on the blood pressure (BP) of transgender individuals.We searched PubMed/MEDLINE, SCOPUS and Cochrane Library databases for articles published relating to the BP of transgender adults commencing GHT. Methodological quality was assessed via the ‘Quality Assessment Tool for Before–After (Pre–Post) Studies with No Control Group’.Six hundred articles were screened, of which 14 studies were included in this systematic review encompassing 1309 individuals (∼50% transgender men and women) treated with GHT between 1989 and 2019. These articles were all pre–post observational studies without control groups. Mean ages ranged between 23.0–36.7 years (transgender men) and 25.2–34.8 years (transgender women). Interventions were diverse and included oral, transdermal and injectable hormonal preparations with 4 months to 5 years follow-up. Most studies in transgender men did not demonstrate a change in BP, whereas transgender women on GHT demonstrated both increases and decreases in SBP. These studies were heterogenous with significant methodological limitations and only two were determined to have a good quality rating.There is currently insufficient data to advise the impact of GHT on BP in transgender individuals. Better quality research is essential to elucidate whether exogenous sex hormones modulate BP in transgender people and whether this putative alteration infers poorer cardiovascular outcomes. Transgender people experience gender dysphoria due to incongruence between their gender identity and the sex they were assigned at birth . Gender-The recent substantive increases in population prevalence of transgender people requires the implementation of evidence-based guidance to better protect the health of this population –4. HowevConsequently, international guidelines, set out by the Endocrine Society and World Professional Association for Transgender Health, have been cautious in their recommendations regarding modifiable risk factors for cardiovascular disease in this population ,9. HyperA comprehensive overview is therefore required to assess the impact of GHT on the BP. Our aim was to perform a systematic review of the relationship of exogenous sex hormones and SBP and DBP in transgender men and women commencing treatment.We included randomized trials and observational studies of transgender individuals who used GHT regardless of gender-reassignment surgery status. Eligible studies included transgender men prescribed testosterone and transgender women prescribed estrogen, antiandrogens  or GnRH agonists. Studies were included regardless of dose of GHT. Studies were required to provide a comparison of BP before and after/during treatment for a minimum of 3 months. Articles with participants under the age of 16 were excluded in addition to review articles, commentaries and letters that did not contain original data. BP measurements could include manual, automated or ambulatory recordings. Many transgender individuals receiving GHT may be gender non-binary , and may not consider themselves as simply men or women [The current systematic review adhered to the Preferred Reporting Items for Systematic Reviews guidelines . PubMed/The following medical subject headings were used in the search: ‘blood pressure’ AND ‘transgender’ OR ‘transgender person’ OR ‘person, transgender’ OR ‘persons, transgender’ OR ‘transgender persons’ OR ‘transmasculine’ OR ‘transfeminine’ OR ‘trans masculinization’ OR ‘trans feminization’ OR ‘gender incongruent’ OR ‘gender dysphoric’ OR ‘gender affirming’ OR ‘transsexual persons’ OR ‘person, transsexual’ OR ‘persons, transsexual’ OR ‘transsexual person’ OR ‘transgender male’ OR ‘transgender female’ OR ‘transgender man’ OR ‘transgender woman’ OR ‘trans man’ OR ‘trans woman’ OR ‘cross-sex’.The literature search, data extraction and quality assessment were conducted independently by two investigators (P.J.C. and A.C.). In the case of disagreement between the two reviewers, consensus was achieved after consulting with a third reviewer (C.D.). Duplicate records were removed and study titles and abstracts were screened to identify potentially eligible articles for inclusion in the full text review. The selected articles were read in full for confirmation of eligibility and data extraction. Data extracted from these articles included name of the first author, publication year, country, number of participants, duration of the follow-up, intervention (dose and therapy), and SBP and DBP before and after the introduction of GHT.To determine the quality of the included studies the National Institute of Health Quality Assessment Tool for Before–After (Pre–Post) Studies with No Control Group was utilized . This toOur multidatabase literature search identified 600 nonduplicated potentially relevant records Fig. . No recoConsequently, 14 studies were included in this systematic review encompassing 1309 individuals (∼50% transgender men and women) treated with GHT between 1989 and 2019. Follow-up ranged between 4 months and 5 years. 11 of the included studies were undertaken in Europe and three in North America. Mean ages ranged between 23.0–36.7 years in transgender men and 25.2–34.8 years in transgender women.Of the included studies, all studies were pre–post observational studies without control groups. Only one study provided the device used to measure BP  , the posBetween 2003 and 2019 a total of 13 studies measured the SBP and DBP of transgender men receiving GHT (Table n = 8), intramuscular testosterone esters (n = 7), transdermal testosterone gel (n = 2) or patches (n = 1), oral testosterone undecanoate (n = 1), or subcutaneous testosterone cypionate (n = 1). One study did not specify the formulation of intramuscular testosterone administered [Various formulations of testosterone were administered in these studies including intramuscular testosterone undecanoate (nistered .n = 9), whereas three studies reported a significant increase in SBP ranging between 4.3 and 13.3 mmHg [n = 10) did not report a significant change in DBP.As demonstrated in Table 3.3 mmHg ,25,27 an3.3 mmHg . Most stn = 10) of transgender women receiving estrogen therapy comprising of 661 individuals. These studies were undertaken between 1989 and 2019 with a mean follow-up of 16.4 (SD 7.9) months (range 6–31.7 months). The mean sample size of these studies was 66 individuals, with the largest being conducted by van Velzen et al.[Table en et al. of 242 in = 6), estradiol patches (n = 6), estradiol gel (n = 2), oral ethynyl estradiol (n = 2), oral conjugated estrogen (n = 2), sublingual micronized 17β estradiol (n = 1), intramuscular estradiol valerate (n = 2) and unspecified oral estrogen (n = 1), were utilized. Four studies provided transdermal estrogen patches rather than oral estrogen to those over the age of 40–45 years [n = 7), whereas spironolactone (n = 3) and flutamide (n = 1) was also utilized. No study incorporated the use of GnRH analogues while two studies utilized progestogens.The doses and formulations of GHT vary significantly between studies. Oral estradiol valerate  . Howeveret al.[A limitation of this systematic review is that it did not include cross-sectional assessments of the development of hypertension. Asscheman et al. observedet al.. ResultsAs many as 390 adults per 100 000 of the US population identify as transgender and this marginalized group suffer from significant health disparities . To enacFurthermore, in line with recent guidance on BP assessment in clinic-based research, it is recommended that multiple BP readings be taken from a validated and calibrated BP device and averaged at each assessment . MultiplThe majority of studies of transgender men receiving GHT did not demonstrate a significant change in BP, whereas both increases and decreases in SBP were observed in transgender women receiving hormone therapy. Mechanistically, estrogen promotes endothelium-dependent vasorelaxation via increasing nitric oxide bioavailability, expression and activation of endothelial nitric oxide synthase, increases in endothelium-derived hyperpolarizing factor and prostacyclin, and reductions in endothelin-1 –44. EndoHowever, due to the limited quality of the of the studies included in this review, there is insufficient data to determine meaningful conclusions regarding the effect of estrogen or testosterone-based GHT on the SBP or DBPs of transgender individuals or advise clinically on this matter. More robust research is required Table  to deterPrevious presentations: Neither the whole work nor part of the work presented in this article has been previously presented.The current work was supported by the British Heart Foundation (Centre of Research Excellence Awards RE/13/5/30177 and RE/18/6/34217).There are no conflicts of interest.