Stable Oxygen Incorporation in Superconducting TaN: An Experimental and Theoretical Assessment.

Oxide formation in superconducting TaN thin films is analyzed through experimental measurements and computational simulations. TaN was synthesized in an ultrahigh vacuum (UHV) system by reactive pulsed laser deposition and characterized in situ by X-ray photoelectron spectroscopy; it was also characterized ex situ by X-ray diffraction, transmission electron microscopy, and the four-point probe method. Despite being grown in an UHV chamber with a base pressure of 5 × 10-9 Torr, TaN contains a significant amount of oxygen (up to 20 at. %) attributed to residual gases containing O atoms. Several TaN1-x O x models, with different amounts of O atoms incorporated into N sites, were simulated using ab initio calculations to assess the feasibility of oxide formation. Thermodynamic stability analysis reveals that TaN1-x O x stability increases with oxygen addition, indicating that its incorporation is thermodynamically favorable. The oxygen-impurified TaN exhibits a face-centered cubic structure and is a superconductor (R = 0 Ω) at 2.99 K. The results discussed here highlight the importance of considering stable oxygen impurities when studying superconductivity in TaN films. The formation of TaN1-x O x regions in the compound may be key to understanding the variation in critical temperature reported in the literature.

X-Ray-Cosmic-Shear Cross-Correlations: First Detection and Constraints on Baryonic Effects.

We report the first detection, at very high significance (23σ), of the cross-correlation between cosmic shear and the diffuse x-ray background, using data from the Dark Energy Survey and the ROSAT satellite. The x-ray cross-correlation signal is sensitive to the distribution of the surrounding gas in dark matter halos. This allows us to use our measurements to place constraints on key physical parameters that determine the impact of baryonic effects in the matter power spectrum. In particular, we determine the mass of halos in which feedback has expelled half of their gas content on average to be log_{10}(M_{c}/M_{⊙})=13.643_{-0.12}^{+0.081} and the polytropic index of the gas to be Γ=1.231_{-0.011}^{+0.015}. This represents a first step in the direct use of x-ray cross-correlations to obtain improved constraints on cosmology and the physics of the intergalactic gas.

Enhancing quality of life in severe post-COVID-19 survivors through multidisciplinary care.

Background: COVID-19 survivors who were hospitalised continue to experience long-term multisystemic sequelae and symptoms, impacting their health-related quality of life (HRQoL). The complexity of post-COVID-19 conditions underscores the importance of adopting a multidisciplinary, patient-centric approach to ensure ongoing care. This study aims to assess HRQoL and post-COVID symptoms in a cohort of severe COVID-19 survivors depending on their participation in a multidisciplinary programme. Methods: This prospective study was conducted in a post-COVID clinic staffed by a multidisciplinary team (physical rehabilitator, nutritionist, psychologist, including experts in pulmonary rehabilitation, nutrition, psychology and others). Subjects over 18 years old who were hospitalised due to severe COVID-19 during the acute phase and had attended the post-COVID clinic within the first 3 months following discharge were included. Subjects who were unable or unwilling to provide informed consent to participate in the protocol were excluded. Linear mixed-effect models were employed to examine changes in 12-Item Short-Form Health Survey (SF-12) component scores. The resolution of post-COVID symptom clusters was compared using the Cox model. Results: A total of 730 patients were included, with a mean±sd age of 55.78±15.43 years; 60.55% were male and 90.62% required mechanical ventilation during hospitalisation. Programme attendants demonstrated improved SF-12 physical and mental component scores at 3 and 12 months. A reduction in the prevalence of post-COVID symptoms was observed in both groups, with greater reductions in those attending the programme. Conclusion: Our study showed that patients enrolled on the multidisciplinary programme experienced improvements in fatigue, musculoskeletal, gastrointestinal, neuropsychiatric and respiratory symptoms, along with enhanced SF-12 mental and physical component scores.

A New Fibrin-Heparine Coated Self-Expanding Stent for the Rescue Treatment of Intracranial Stenosis-a Multicentric Study.

INTRODUCTION: Rescue intracranial stenting is necessary to provide sufficient recanalization after mechanical thrombectomy (MT) in patients with acute large vessel occlusions (LVO) due to an underlying intracranial atherosclerotic disease (ICAD). The CREDO heal is a novel stent that provides a potentially lower thrombogenicity due to surface modification. We present the first multicentric experience with the CREDO heal for acute rescue stenting. METHODS: Data of 81 patients who underwent rescue stenting after MT at 12 centers in Germany and Spain were prospectively collected and retrospectively evaluated. RESULTS: Final mTICI 2b­3 was reached in 95.1% after median two MT maneuvers and stenting. Four periprocedural complications resulted in clinical deterioration (4.9%). Intraparenchymal hemorrhage occurred in one patient (1.2%) and functional independence at FU was reached by 42% of the patients. Most interventions were performed under Gp IIb/IIIa inhibitors. CONCLUSION: CREDO heal was effective and safe in our case series. However, more data is needed to define the optimal antithrombotic regime. The use under single antiplatelet medication is not supported by our study.

Isolated attosecond pulse generation in a semi-infinite gas cell driven by time-gated phase matching.

Isolated attosecond pulse (IAP) generation usually involves the use of short-medium gas cells operated at high pressures. In contrast, long-medium schemes at low pressures are commonly perceived as inherently unsuitable for IAP generation due to the nonlinear phenomena that challenge favourable phase-matching conditions. Here we provide clear experimental evidence on the generation of isolated extreme-ultraviolet attosecond pulses in a semi-infinite gas cell, demonstrating the use of extended-medium geometries for effective production of IAPs. To gain a deeper understanding we develop a simulation method for high-order harmonic generation (HHG), which combines nonlinear propagation with macroscopic HHG solving the 3D time-dependent Schrödinger equation at the single-atom level. Our simulations reveal that the nonlinear spatio-temporal reshaping of the driving field, observed in the experiment as a bright plasma channel, acts as a self-regulating mechanism boosting the phase-matching conditions for the generation of IAPs.

"Insights into vessel perforations during thrombectomy: Characteristics of a severe complication and the effect of thrombolysis".

INTRODUCTION: Thrombectomy complications remain poorly explored. This study aims to characterize periprocedural intracranial vessel perforation including the effect of thrombolysis on patient outcomes. PATIENTS AND METHODS: In this multicenter retrospective cohort study, consecutive patients with vessel perforation during thrombectomy between January 2015 and April 2023 were included. Vessel perforation was defined as active extravasation on digital subtraction angiography. The primary outcome was modified Rankin Scale (mRS) at 90 days. Factors associated with the primary outcome were assessed using proportional odds models. RESULTS: 459 patients with vessel perforation were included (mean age 72.5 ± 13.6 years, 59% female, 41% received thrombolysis). Mortality at 90 days was 51.9% and 16.3% of patients reached mRS 0-2 at 90 days. Thrombolysis was not associated with worse outcome at 90 days. Perforation of a large vessel (LV) as opposed to medium/distal vessel perforation was independently associated with worse outcome at 90 days (aOR 1.709, p = 0.04) and LV perforation was associated with poorer survival probability (HR 1.389, p = 0.021). Patients with active bleeding >20 min had worse survival probability, too (HR 1.797, p = 0.009). Thrombolysis was not associated with longer bleeding duration. Bleeding cessation was achieved faster by permanent vessel occlusion compared to temporary measures (median difference: 4 min, p < 0.001). DISCUSSION AND CONCLUSION: Vessel perforation during thrombectomy is a severe and frequently fatal complication. This study does not suggest that thrombolysis significantly attributes to worse prognosis. Prompt cessation of active bleeding within 20 min is critical, emphasizing the need for interventionalists to be trained in complication management.

New findings in the metabolism of the saffron apocarotenoids, crocins and crocetin, by the human gut microbiota.

The main constituents of saffron are the apocarotenoids crocins and crocetin, present in the stigmas. Numerous healthy properties, especially those related to the effects on the central nervous system, have been attributed to these compounds but the metabolites responsible for these effects are still unknown. Previous evidences in animal models suggest a role for the gut microbiota in the pharmacokinetics and the neuroprotective effects of these compounds. However, the interaction between these apocarotenoids and the gut microbiota has been poorly studied. In this article, we have thoroughly investigated the batch fermentation of crocin-1 and crocetin (10 µM) with human fecal samples of two donors at different incubation times (0-240 h) using a metabolomic approach. We corroborated a rapid transformation of crocin-1 which looses the glucose molecules through de-glycosylation reactions until its complete transformation into crocetin in 6 hours. A group of intermediate crocins with different degrees of glycosylation were detected in a very short time. Crocetin was further metabolized and new microbial metabolites produced by double-bond reduction and demethylation reactions were identified for the first time: dihydro and tetrahydro crocetins and di-demethyl crocetin. In addition, we detected changes in the levels of the short chain fatty acids valeric acid and hexanoic acid suggesting further structural modifications of crocetin or changes in the catabolic production of these compounds. This research is a pioneering study of the action of the human gut microbiota on the saffron apocarotenoids and goes one step further towards the discovery of metabolites potentially involved in the benefits of saffron.

A one-pot five component reaction for the synthesis of tetrazol-benzofuran hybrids and their inhibitory activity against Mucor lusitanicus.

A synthetic strategy for obtaining a new series of 1,5-disubstituted tetrazole-benzofuran hybrid systems via a one-pot five-component reaction is described. This process involves a Ugi-azide multicomponent reaction coupled to an intramolecular cyclization catalyzed by Pd/Cu, resulting in low to moderate yields from 21 to 67%. This protocol allowed the synthesis of highly substituted benzofurans at the 2-position through an operationally simple process under mild reaction conditions and with high bond forming efficiency due to the formation of six new bonds (two C-C, two C-N, one N-N, and one C-O). Besides, to evaluate the antifungal activity of 1,5-disubstituted tetrazole-benzofurans 9a-n, in vitro studies against Mucor lusitanicus were performed, finding that compound 9b exhibits bioactivity comparable to the commercial antifungal drug Amphotericin B. These results suggest potential for use in controlling mucormycosis infections in animal models, highlighting the importance of these findings given the limited antifungal drug options and high mortality rates associated with this infection.

Extrinsically conducting MOFs: guest-promoted enhancement of electrical conductivity, thin film fabrication and applications.

Conductive metal-organic frameworks are of current interest in chemical science because of their applications in chemiresistive sensing, electrochemical energy storage, electrocatalysis, etc. Different strategies have been employed to design conductive frameworks. In this review, we discuss the influence of different types of guest species incorporated within the pores or channels of metal-organic frameworks (MOFs) and porous coordination polymers (PCPs) to generate charge transfer pathways and modulate their electrical conductivity. We have classified dopants or guest species into three different categories: (i) metal-based dopants, (ii) molecule and molecular entities and (iii) organic conducting polymers. Different types of metal ions, metal nano-clusters and metal oxides have been used to enhance electrical conductivity in MOFs. Metal ions and metal nano-clusters depend on the hopping process for efficient charge transfer whereas metal-oxides show charge transport through the metal-oxygen pathway. Several types of molecules or molecular entities ranging from neutral TCNQ, I2, and fullerene to ionic methyl viologen, organometallic like nickelcarborane, etc. have been used. In these cases, the charge transfer process varies with the guest species. When organic conducting polymers are the guest, the charge transport occurs through the polymer chains, mostly based on extended π-conjugation. Here we provide a comprehensive and critical review of these strategies to add electrical conductivity to the, in most cases, otherwise insulating MOFs and PCPs. We point out the guest encapsulation process, the geometry and structure of the resulting host-guest complex, the host-guest interactions and the charge transport mechanism for each case. We also present the methods for thin film fabrication of conducting MOFs (both, liquid-phase and gas-phase based methods) and their most relevant applications like electrocatalysis, sensing, charge storage, photoconductivity, photocatalysis,… We end this review with the main obstacles and challenges to be faced and the appealing perspectives of these 21st century materials.

In Vivo Tracking and 3D Mapping of Cell Death in Regeneration and Cancer Using Trypan Blue.

Tracking cell death in vivo can enable a better understanding of the biological mechanisms underlying tissue homeostasis and disease. Unfortunately, existing cell death labeling methods lack compatibility with in vivo applications or suffer from low sensitivity, poor tissue penetration, and limited temporal resolution. Here, we fluorescently labeled dead cells in vivo with Trypan Blue (TBlue) to detect single scattered dead cells or to generate whole-mount three-dimensional maps of large areas of necrotic tissue during organ regeneration. TBlue effectively marked different types of cell death, including necrosis induced by CCl4 intoxication in the liver, necrosis caused by ischemia-reperfusion in the skin, and apoptosis triggered by BAX overexpression in hepatocytes. Moreover, due to its short circulating lifespan in blood, TBlue labeling allowed in vivo "pulse and chase" tracking of two temporally spaced populations of dying hepatocytes in regenerating mouse livers. Additionally, upon treatment with cisplatin, TBlue labeled dead cancer cells in livers with cholangiocarcinoma and dead thymocytes due to chemotherapy-induced toxicity, showcasing its utility in assessing anticancer therapies in preclinical models. Thus, TBlue is a sensitive and selective cell death marker for in vivo applications, facilitating the understanding of the fundamental role of cell death in normal biological processes and its implications in disease.

Bridge vs Terminal Cyano-coordination in Binuclear Cobalt Porphyrin Dimers: Interplay of Electrons between Metal and Ligand and Spin-Coupling via Bridge.

Three cyano-coordinated cobalt porphyrin dimers were synthesized and thoroughly characterized. The X-ray structure of the complexes reveals that cyanide binds in a terminal fashion in both the anti and trans isomers of ethane- and ethylene-bridged cobalt porphyrin dimers, while in the cis ethylene-bridged dimer, cyanides bind in both terminal and bridging modes. The nonconjugated ethane-bridged complex stabilizes exclusively a diamagnetic metal-centered oxidation of type CoIII(por)(CN)2 both in the solid and in solution. In contrast, the complexes with the conjugated ethylene-bridge contain signatures of both paramagnetic ligand-centered oxidation of the type CoII(por•+)(CN)2 and diamagnetic metal-centered oxidation of type CoIII(por)(CN)2 with the metal-centered oxidized species being the major component in the solid state as observed in XPS, while the ligand-centered oxidized species are present in a significant amount in solution. 1H NMR spectrum in solution displays two set of signals corresponding to the simultaneous presence of both the diamagnetic and paramagnetic species. EPR and magnetic investigation reveal that there is a moderate ferromagnetic coupling between the unpaired electrons of the low-spin CoII center and the porphyrin π-cation radical in CoII(por•+)(CN)2 species as well as an antiferromagnetic coupling between the two CoII(por•+) units through the ethylene and CN bridges.

Reconstruction Techniques and Associated Morbidity in Minimally Invasive Gastrectomy for Cancer - Insights from the GastroBenchmark and GASTRODATA databases.

OBJECTIVE/BACKGROUND: Various anastomotic and reconstruction techniques are used for minimally invasive total (miTG) and distal gastrectomy (miDG). Their effects on postoperative morbidity have not been extensively studied. METHODS: MiTG and miDG patients were selected from 9356 oncological gastrectomies performed 2017-2021 in 44 centers. Endpoints included anastomotic leakage (AL) rate and postoperative morbidity tested by multivariable analysis. RESULTS: Three major anastomotic techniques (circular stapled (CS); linear stapled (LS); hand sewn (HS)), and three major bowel reconstruction types (Roux (RX); Billroth I (BI); Billroth II (BII)) were identified in miTG (n=878) and miDG (n=3334). Postoperative complications including AL (5.2% vs. 1.1%), overall (28.7% vs. 16.3%) and major morbidity (15.7% vs. 8.2%), as well as 90-day mortality (1.6% vs. 0.5%) were higher after miTG compared with miDG. After miTG, AL rate was higher after CS (4.3%) and HS (7.9%) compared with LS (3.4%). Similarly, major complications (LS: 9.7%, CS: 16.2%, HS: 12.7%) were lowest after LS. Multivariate analysis confirmed anastomotic technique as predictive factor for AL, overall and major complications. In miDG, AL rate (BI: 1.4%, BII 0.8%, RX 1.2%), overall (BI: 14.5%, BII: 15.0%, RX: 18.7%,) and major morbidity (BI: 7.9%, BII: 9.1%, RX: 7.2%), and mortality (BI: 0%, BII: 0.1%, RY: 1.1%%) were not affected by bowel reconstruction. CONCLUSION: In oncologically suitable situations, miDG should be preferred to miTG, as postoperative morbidity is significantly lower. LS should be a preferred anastomotic technique for miTG in Western Centers. Conversely, bowel reconstruction in DG may be chosen according to surgeon's preference.

The abundant fraction of soil microbiomes regulates the rhizosphere function in crop wild progenitors.

The rhizosphere influence on the soil microbiome and function of crop wild progenitors (CWPs) remains virtually unknown, despite its relevance to develop microbiome-oriented tools in sustainable agriculture. Here, we quantified the rhizosphere influence-a comparison between rhizosphere and bulk soil samples-on bacterial, fungal, protists and invertebrate communities and on soil multifunctionality across nine CWPs at their sites of origin. Overall, rhizosphere influence was higher for abundant taxa across the four microbial groups and had a positive influence on rhizosphere soil organic C and nutrient contents compared to bulk soils. The rhizosphere influence on abundant soil microbiomes was more important for soil multifunctionality than rare taxa and environmental conditions. Our results are a starting point towards the use of CWPs for rhizosphere engineering in modern crops.

Tetranuclear NiII-Mannich base complex with oxygenase, water splitting and ferromagnetic and antiferromagnetic coupling properties.

A new Mannich base (2-(4-(2-hydroxy-3-methoxy-5-methylbenzyl)-piperazin-1-yl)methyl)-6-methoxy-4-ethylphenol (H2L) and its tetranuclear NiII complex [Ni4L2(µ1,1-Cl)2(H2O)4]Cl2 (compound 1) are characterised using single-crystal X-ray diffraction measurements. Compound 1 contains four different NiII centres in a rhombus-like structure. Two Ni atoms (Ni1 and Ni2) have a NiN2O4 coordination sphere, while the other two (Ni3 and Ni4) have a NiO4Cl2 coordination environment and Ni-Cl-Ni bridges connect them. Ni1 and Ni2 are linked to Ni3 and Ni4 by phenoxide bridges. Variable temperature magnetic susceptibility measurements of 1 indicate the presence of alternating antiferromagnetic coupling (J1 = -6.6(1) cm-1) through the phenoxide bridge along the sides of the rhombus and ferromagnetic coupling (J2 = 8.4(1) cm-1) through the double Cl bridge along the short diagonal of the rhombus with a zero-field splitting of |D| = 2.7(1) cm-1. Compound 1 shows oxidase (catecholase-like and phenoxazinone synthase-like) activity. The oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC) gives 3,5-di-tert-butylquinone (3,5-DTBQ) and H2O2 and the oxidation of o-aminophenol (OAP) produces 2-aminophenoxazin-3-one (APX) and H2O with turnover numbers of 28.32 and 17.52 h-1, respectively, under aerobic conditions. A mechanism for the oxidase activity catalysed by compound 1 is proposed in line with ESI-mass spectrometry, EPR spectroscopy, and electrochemical data. The reaction involves the cleavage of the tetranuclear Ni4-core to form a mononuclear NiII complex in the presence of the substrate (3,5-DTBC/OAP). This NiII complex is reduced to NiI with the concomitant oxidation of the substrate (3,5-DTBQ/APX). Formation of a radical intermediate is confirmed using EPR. In the catecholase-like activity, O2 is reduced to H2O2 while in the phenoxazinone synthase-like activity O2 produces H2O. Compound 1 participated in oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in a strongly basic medium with an onset potential of 418 mV and a Tafel slope of 121 mV dec-1 for OER and an onset potential of 477 mV and Tafel slope of 146 mV dec-1 for HER.

Ultradense Array of On-Chip Sensors for High-Throughput Electrochemical Analyses.

High-throughput sensors are valuable tools for enabling massive, fast, and accurate diagnostics. To yield this type of electrochemical device in a simple and low-cost way, high-density arrays of vertical gold thin-film microelectrode-based sensors are demonstrated, leading to the rapid and serial interrogation of dozens of samples (10 µL droplets). Based on 16 working ultramicroelectrodes (UMEs) and 3 quasi-reference electrodes (QREs), a total of 48 sensors were engineered in a 3D crossbar arrangement that devised a low number of conductive lines. By exploiting this design, a compact chip (75 × 35 mm) can enable performing 16 sequential analyses without intersensor interferences by dropping one sample per UME finger. In practice, the electrical connection to the sensors was achieved by simply switching the contact among WE adjacent fingers. Importantly, a short analysis time was ensured by interrogating the UMEs with chronoamperometry or square wave voltammetry using a low-cost and hand-held one-channel potentiostat. As a proof of concept, the detection of Staphylococcus aureus in 15 samples was performed within 14 min (20 min incubation and 225 s reading). Additionally, the implementation of peptide-tethered immunosensors in these chips allowed the screening of COVID-19 from patient serum samples with 100% accuracy. Our experiments also revealed that dispensing additional droplets on the array (in certain patterns) results in the overestimation of the faradaic current signals, a phenomenon referred to as crosstalk. To address this interference, a set of analyses was conducted to design a corrective strategy that boosted the testing capacity by allowing using all on-chip sensors to address subsequent analyses (i.e., 48 samples simultaneously dispensed on the chip). This strategy only required grounding the unused rows of QRE and can be broadly adopted to develop high-throughput UME-based sensors. In practice, we could analyze 48 droplets (with [Fe(CN)6]4-) within ∼8 min using amperometry.

Acute effects of a vigorous-intensity warm-up on response suppression and decision-making of football referees.

This study investigates the acute effect of physical exercise simulating a standard pre-competitive warm-up on the response suppression and decision-making of football referees. Thirty-four referees (n = 17 - regional level; n = 17 - national level) participated in the study. A Stop-Signal Task (SST) and a decision-making video test were used to evaluate the referees' perceptual-cognitive functions. The findings revealed that the vigorous aerobic exercise acutely impacted basic cognitive functions, as indicated by decreased reaction time and decreased choice accuracy. However, higher-order cognitive functions such as response suppression and decision-making did not exhibit significant changes post-exercise. Based on these results, there is no evidence to suggest that a vigorous-intensity warm-up is likely to favour response suppression and decision-making factors in the initial phases of the game. National referees showed superior response suppression abilities (shorter stop-signal reaction times and lower probability of responding to the stop-signal) than regional referees, indicating that higher-level referees possess enhanced perceptual-cognitive skills, likely influenced by their experience. Further studies are required to determine whether these variables can be acutely improved through physical exercise. In this regard, our results suggest the need for alternative strategies in pre-competitive referee warm-ups if aiming to improve perceptual-cognitive skills in the initial phases of the game.

Right ventricular dysfunction: pathophysiology, experimental models, evaluation, and treatment.

Interest in the right ventricle has substantially increased due to advances in knowledge of its pathophysiology and prognostic implications across a wide spectrum of diseases. However, we are still far from understanding the multiple mechanisms that influence right ventricular dysfunction, its evaluation continues to be challenging, and there is a shortage of specific treatments in most scenarios. This review article aims to update knowledge about the physiology of the right ventricle, its transition to dysfunction, diagnostic tools, and available treatments from a translational perspective.

Exploring the fate of phlorotannins from Laminaria digitata across the gastrointestinal tract: Insights into susceptibility and bioactivity prior and post gastrointestinal digestion.

Phlorotannins are phenolic compounds exclusive from brown macroalgae endowed with promising bioactive properties. However, considering that diet is their main route of entrance to our system, gastrointestinal digestion might affect such bioactive properties. Here, phlorotannin extracts obtained from Laminaria digitata were submitted to simulated gastrointestinal digestion to evaluate its impact on their antioxidant and anti-inflammatory properties. Overall, a reduction of the total phlorotannin content along the gastrointestinal tract was noticed, although the antioxidant activity measured in vitro via NO● and O2●- scavenging assays, maintained almost the same. The crude extract (70 % v/v acetone) exhibited superior inhibition of NO● release on lipopolysaccharide-stimulated cells after digestion. In contrast, the opposite occurred to the phlorotannin-purified extract, indicating that the digestive process favors the anti-inflammatory properties of the former but not the latter. Data collected from UHPLC-MS analysis revealed that the fuhalol and carmalol-type compounds were completely absent from the digested phlorotannin-purified extract, which could partly explain its lower anti-inflammatory activity compared with its non-digested counterpart. Overall, this study contributes to a better understanding of the impact of gastrointestinal digestion on the bioactivity profile of L. digitata phlorotannins, demonstrating that fuhalols and carmalols are particularly susceptible to the digestive process.

Difluorenoheteroles: topological control of π conjugation in diradicaloids and mixed-valence radical ions.

Two families of difluorenoheterole diradicaloids were synthesized, featuring isomeric ring systems with distinct conjugation topologies. The two types of difluorenoheteroles contain, respectively, a Chichibabin-like motif (CH) and a newly introduced heteroatom-linked triphenylmethyl dyad (TD-X). Combined experimental and theoretical investigations show that the TD-X systems have reduced quinoidal character but the interaction between formal spin centers is sufficiently strong to ensure a singlet ground state. The singlet-triplet energy gaps in the TD-X difluorenoheteroles are strongly affected by the heterocyclic ring, with values of -4.3 and -0.7 kcal mol-1 determined for the pyrrole- and thiophene-containing analogues, respectively. In cyclic voltammetry experiments, the TD-X systems show diminished energy gaps and superior reversibility in comparison with their CH counterparts. The radical anions and cations obtained from these diradicaloids show extremely red-shifted bands, occasionally with λ max > 3500 nm. Computational studies show that some of these ions adopt distonic structures and may be characterized as class-II mixed-valence species.