Dissociative States Research Articles

The clinical neuroscience of lucid dreaming.

During most dreams, the dreamer does not realize that they are in a dream. In contrast, lucid dreaming allows to become aware of the current state of mind, often accompanied by considerable control over the ongoing dream episode. Lucid dreams can happen spontaneously or be induced through diverse behavioural, cognitive or technological strategies. Such induction techniques have spurred research into the potential therapeutic aspects of lucid dreams. In this review, we gather evidence on the link between lucid dreams and conditions like nightmare disorder, depression, anxiety, psychosis, and dissociative states, and highlight the possible neurobiological basis of these associations. Furthermore, we explore contemplative sleep practices that train lucid states during sleep, such as Dream/Sleep Yoga and Yoga Nidrâ. The potential drawbacks of lucid dreaming interventions are outlined, accompanied by an examination of the impacts of lucid dreams on individuals without clinical conditions. By shedding light on these intricate relationships, the review contributes to a deeper understanding of the therapeutic possibilities and implications of lucid dreaming.

Neurophysiological correlates of ketamine-induced dissociative state in bipolar disorder: insights from real-world clinical settings.

Ketamine, a dissociative compound, shows promise in treating mood disorders, including treatment-resistant depression (TRD) and bipolar disorder (BD). Despite its therapeutic potential, the neurophysiological mechanisms underlying ketamine's effects are not fully understood. This study explored acute neurophysiological changes induced by subanesthetic doses of ketamine in BD patients with depression using electroencephalography (EEG) biomarkers. A cohort of 30 BD (F = 12) inpatients with TRD undergoing ketamine treatment was included in the study. EEG recordings were performed during one of the ketamine infusions with doses ranging from 0.5 to 1 mg/kg, and subjective effects were evaluated using the Clinician-Administered Dissociative States Scale (CADSS). Both rhythmic and arrhythmic features were extrapolated from the EEG signal. Patients who exhibited a clinical response to ketamine treatment within one week were classified as early responders(ER), whereas those who responded later were categorized as late responders (LR). Ketamine reduced low-frequency spectral power density while increasing gamma oscillatory power. Additionally, ketamine flattened the slope of the power spectra, indicating altered scale-free dynamics. Ketamine also increased brain signal entropy, particularly in high-frequency bands. Notably, LR exhibited greater EEG changes compared to ER, suggesting endophenotypic differences in treatment sensitivity. These findings provide valuable insights into the neurophysiological effects of ketamine in BD depression, highlighting the utility of EEG biomarkers for assessing ketamine's therapeutic mechanisms in real-world clinical settings. Understanding the neural correlates of ketamine response may contribute to personalized treatment approaches and improved management of mood disorders.

Non vertical ionization-dissociation model for strong IR induced dissociation dynamics of

Electron-nuclear coupling plays a crucial role in strong laser induced molecular dissociation dynamics. The interplay between electronic and nuclear degrees of freedom determines the pathways and outcomes of molecular fragmentation. However, a full quantum mechanical treatment of electron-nuclear dynamics is computationally intensive. In this work, we have developed a Strong Laser Induced non-adiabatic Multi-Ionic-Multi-Electric States (SLIMIMES) approach, which contains the electron-laser and electron-nuclear couplings. We validate our model using a showcase example: water dissociation under strong infrared (IR) laser pulses. Our investigation reveals the predominant role of a non-vertical dissociation pathway in the photo-ionization dissociation (PID) process of . This pathway originates from neutral , which undergoes vertical multi-photon-single-ionization, reaching the intermediate dissociation states of within . Subsequently, dissociates into , with both and fragments potentially ionizing an electron during interaction with the IR laser. This sequential PID pathway significantly contributes to the dissociation yields of water dication. Our calculations are consistent with recent experimental data, which focus on measuring the branching ratio of water dication dissociation. We aim for our model to provide a deeper understanding and a fresh perspective on the coupling between electron and nuclear dynamics induced by a strong IR laser field.

Protein stabilization in spray drying and solid-state storage by using a 'molecular lock' - exploiting bacterial adaptations for industrial applications.

Small, stable biomedicines, like peptides and hormones, are already available on the market as spray dried formulations, however large biomolecules like antibodies and therapeutic enzymes continue to pose stability issues during the process. Stresses during solid-state formation are a barrier to formulation of large biotherapeutics as dry powders. Here, we explore an alternative avenue to protein stabilisation during the spray drying process, moving away from the use of excipients. In thermophilic proteins, the presence of C-termini extensions can add to their stability by increasing molecular rigidity. Hence, we explored a unique thermostable amino acid extension in the C-terminal of an aldehyde dehydrogenase tetramer originating from Thermus thermophilus HB27 (ALDHTt), and its ability to stabilise the large enzyme against drying stresses. The presence of the C-terminal extension was found to act like a 'molecular lock' of the oligomeric state of the ALDH tetramer upon spray drying. Removal of the extension, mimicking the structure of mesophilic ALDHs, promoted the formation of aggregates and dissociative states. The ALDH protein with the 'molecular lock' retained ∼24% more activity after spray drying and retained up to 16% more activity during solid state storage than its mutant. We proposed a mechanism for the protection of oligomeric proteins by the distinct C-terminal extension under stresses involved in solid formation. Additionally, the process of spray drying an excipient-free ALDH is achieved using a design of experiments approach, increasing its breadth of application in the biocatalysis of aldehydes.

Surface Orientation Dependent Dissociation of Formic Acid and Adsorption States of Formate on Copper

Surface Orientation Dependent Dissociation of Formic Acid and Adsorption States of Formate on Copper

Determining Key Factors for the Open-Loop Control of Molecular Fragmentation Using Shaped Strong Fields.

Pulse shaping has long been employed for tailoring femtosecond laser pulses to study and control the fragmentation of polyatomic molecules. In many cases, a physical explanation connecting the properties of the field to the observed control is difficult to ascertain. We utilized 80 bit binary spectral phase functions to parametrize and map the search space, gaining insight into which pulse parameters most impact the ion yield and fragmentation pattern for the relatively large triethylamine [N(C2H5)3] molecule. Pulse structures used to control the m/z 86 branching ratio beyond a simple intensity dependence are identified and compared to pump-probe results. All of these findings are explained in terms of control via a dissociative Rydberg state in the neutral molecule. This methodology may be used to discover new control mechanisms and shed light onto which pulse parameters most influence the interaction between strong field lasers and matter.

Prior memory responses modulate behavior and brain state engagement

Memory encoding and retrieval constitute neurally dissociable brain states and prior behavioral work suggests that these states may linger in time. Thus memory states may influence both the current experience and subsequent events; however, this account has not been directly tested. To test the hypothesis that memory judgments induce brain states that persist for several hundred milliseconds, we recorded scalp electroencephalography while participants completed a recognition task. We used an independently validated multivariate mnemonic state classifier to assess memory state engagement. We replicate previous behavioral findings, yet we find that memory states are modulated by response congruency. We find strong retrieval state engagement on incongruent trials, when the response switches between two consecutive trials. These findings indicate that cortical brain states are influenced by prior judgments and suggest that a non-mnemonic, internal attention state may be recruited in the face of changing demands in a dynamic environment.

Ketamine for treatment-resistant obsessive-compulsive disorder: Double-blind active-controlled crossover study.

Obsessive-Compulsive Disorder (OCD) may respond to ketamine treatment. To examine the responsiveness and tolerability of treatment-refractory OCD to intramuscular (IM) ketamine compared to IM fentanyl. This was a randomised double-blind psychoactive-controlled study with single doses of racemic ketamine 0.5 mg/kg, 1.0 mg/kg or fentanyl 50 µg (psychoactive control). Pre-dosing with 4 mg oral ondansetron provided nausea prophylaxis. Eligible participants were aged between 18 and 50 years with severe treatment-resistant OCD. The primary efficacy measure was the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS). Tolerability was measured with the Clinician-Administered Dissociative States Scale (CADSS). Repeated measures analysis of variance with orthogonal polynomial trends was used to assess the effect of drug treatment on Y-BOCS and CADSS scores. Twelve participants were randomised and 10 completed the study (7 females, 3 males, mean age 33 years). Two participants dropped out due to not tolerating dissociative effects associated with the study medication. The reductions in Y-BOCS scores were greater and statistically dose-related for both ketamine doses than fentanyl (dose [linear], F(1, 9) = 6.5, p = 0.031). Score changes for all treatments were maximal at 1-2 h with a steady separation of scores out to 168 h. Ketamine was associated with short-term dissociative and cardiovascular effects. We provide further preliminary evidence for the efficacy and tolerability of IM ketamine in an outpatient cohort of OCD. Additional work is required to establish the optimal dosing regimen and longer-term role of ketamine for OCD. These findings are encouraging given the well-known limitations that exist for treatments in this area.

Different Photodissociation Mechanisms in Fe(CO)5 and Cr(CO)6 Evidenced with Femtosecond Valence Photoelectron Spectroscopy and Excited-State Molecular Dynamics Simulations.

Measured and calculated time-resolved photoelectron spectra and excited-state molecular dynamics simulations of photoexcited gas-phase molecules Fe(CO)5 and Cr(CO)6 are presented. Samples were excited with 266 nm pump pulses and probed with 23 eV photons from a femtosecond high-order harmonic generation source. Photoelectron intensities are seen to blue-shift as a function of time from binding energies characteristic of bound electronic excited states via dissociated-state energies toward the energies of the dissociated species for both Fe(CO)5 and Cr(CO)6, but differences are apparent. The excited-state and dissociation dynamics are found to be faster in Cr(CO)6 because the repopulation from bound excited to dissociative excited states is faster. This may be due to stronger coupling between bound and dissociative states in Cr(CO)6, a notion supported by the observation that the manifolds of bound and dissociative states overlap in a narrow energy range in this system.

Linker‐Mediated Delocalized Excited States in Dimeric Acceptors Enable Efficient Exciton Dissociation with Negligible Energy‐Level Offsets

AbstractEfficient exciton dissociation at low energy offsets is key to overcoming voltage losses in organic solar cells. In this work, we developed two dimeric acceptors, i‐YT and o‐YT, by precisely controlling the position of an asymmetric electron‐donating linker. It induced the foldamer conformation of i‐YT with a para linkage (relative to the dicyano groups), while retaining the unfold conformation for o‐YT. This subtle structural modification influenced the molecular assembly properties, enabled near‐zero energy offset exciton dissociation and power conversion efficiencies exceeding 18 % for i‐YT based organic solar cells. Detailed excitonic dynamics further revealed that the linker position critically influences three processes: the formation of delocalized singlet excited states, ultrafast charge transfer (~5 ps) in solid blends, and the suppression of exciton recombination. Additionally, devices based on i‐YT demonstrated outstanding long‐term stability, retaining 85 % of their initial efficiency after 1,400 hours of continuous illumination. These findings introduce a new class of dimeric acceptors that combine high efficiency with exceptional stability, offering a promising pathway toward low‐energy‐loss organic photovoltaics.

Linker-Mediated Delocalized Excited States in Dimeric Acceptors Enable Efficient Exciton Dissociation with Negligible Energy-Level Offsets.

Efficient exciton dissociation at low energy offsets is key to overcoming voltage losses in organic solar cells. In this work, we developed two dimeric acceptors, i-YT and o-YT, by precisely controlling the position of an asymmetric electron-donating linker. It induced the foldamer conformation of i-YT with a para linkage (relative to the dicyano groups), while retaining the unfold conformation for o-YT. This subtle structural modification influenced the molecular assembly properties, enabled near-zero energy offset exciton dissociation and power conversion efficiencies exceeding 18 % for i-YT based organic solar cells. Detailed excitonic dynamics further revealed that the linker position critically influences three processes: the formation of delocalized singlet excited states, ultrafast charge transfer (~5 ps) in solid blends, and the suppression of exciton recombination. Additionally, devices based on i-YT demonstrated outstanding long-term stability, retaining 85 % of their initial efficiency after 1,400 hours of continuous illumination. These findings introduce a new class of dimeric acceptors that combine high efficiency with exceptional stability, offering a promising pathway toward low-energy-loss organic photovoltaics.

Dissociation of Attentional State and Behavioral Outcome Using Local Field Potentials.

Successful behavior depends on the attentional state and other factors related to decision-making, which may modulate neuronal activity differently. Here, we investigated whether attentional state and behavioral outcome (i.e., whether a target is detected or missed) are distinguishable using the power and phase of local field potential recorded bilaterally from area V4 of two male rhesus monkeys performing a cued visual attention task. To link each trial's outcome to pairwise measures of attention that are typically averaged across trials, we used several methods to obtain single-trial estimates of spike count correlation and phase consistency. Surprisingly, while attentional location was best discriminated using gamma and high-gamma power, behavioral outcome was best discriminated by alpha power and steady-state visually evoked potential. Power outperformed absolute phase in attentional/behavioral discriminability, although single-trial gamma phase consistency provided reasonably high attentional discriminability. Our results suggest a dissociation between the neuronal mechanisms that regulate attentional focus and behavioral outcome.

Mechanism of UV photodegradation of fluoroquinolone antibiotic ciprofloxacin in aqueous solutions

Mechanism of direct UV photolysis of the zwitterionic and anionic forms of the quinolone antibiotic ciprofloxacin (CIP) was revealed by combination of nanosecond laser flash photolysis, steady-state photolysis coupled with high resolution LC-MS and DFT quantum-chemical calculations. For both forms, the main intermediate is a dissociative triplet state, which loses a fluorine ion to form a triplet carbocation; subsequent solvent attack of the latter leads to the formation of products of hydroxylation both the aromatic ring and the piperazyl substituent. Correspondingly, the quantum yield of photolysis of both CIP forms does not depend on the excitation wavelength, but depends on the concentration of dissolved oxygen. Secondary photolysis leads to a number of products of oxidation of the aromatic system, as well as oxidation, opening and full destruction of the piperazinyl substituent. The results obtained may be important for understanding the fate of quinolone antibiotics in UVC disinfection processes and in natural waters under the action of sunlight.

Photophysics and photochemistry of (n-Bu4N)2[Pt(NO3)6] in acetonitrile: ultrafast pump-probe spectroscopy and quantum chemical insight.

The ultrafast processes caused by photoexcitation of (n-Bu4N)2[Pt(NO3)6] complex in acetonitrile were studied by means of transient absorption (TA) pump-probe spectroscopy and verified by quantum chemical calculations. The primary photochemical process was found to be an inner-sphere electron transfer followed by an escape of an •NO3 radical to the bulk solution. The reaction occurs via the dissociative triplet excited LMCT state of the initial complex. Based on the experimental data and quantum chemical calculations, the mechanism of ultrafast photophysical and photochemical processes is proposed.

Social Democratic Hauntings: On Swedish Dissociation and Melancholia

Abstract Once seen as a Western frontrunner of social progressivism and equality, Sweden has undergone momentous changes since the aggressive neoliberal dismantling of the postwar universal welfare state model started in the 1980s; today it is a stronghold of the European far right and has one of the highest levels of wealth inequality in the world. This essay analyzes the contemporary post–social democratic political landscape in Sweden, arguing that it is characterized by a state of both dissociation and melancholia, interlinked affective responses to the intensifying social pressures and structural crises the country faces. While the Right mobilizes racial melancholia to conjure up the stability of the past, significant segments of the political spectrum—including the Left—have long been demobilized by the stranglehold of a form of tragic optimism produced by a post-1991 fusion between the twentieth-century social democratic construction of Swedish exceptionalism and a neoliberal Fukuyaman triumphalism that disavows history and historical change. The essay traces this crisis of historical consciousness back to the hegemony of the Swedish Social Democratic Party in the twentieth century and the genre of folkhemmet nationalism that underpinned its project and whose affective afterlives continue to inform the political impasses we see today.

Engaging the Concepts of Bimetallicity and Mechanical Strain for N2 Activation: A Computational Exploration.

N2 activation is a vital step in the process toward NH3 production. NH3 synthesis has been considered a crucial process for the production of value-added chemicals and/or hydrogen carriers over recent years. In this work, density functional theory (ab initio) calculations are implemented for a thorough screening of bimetallic alloy surfaces using Fe, Ru, and Mo as the matrix (host) metals and Ag, Au, Co, Cu, Fe, Mo, Ni, Pd, Pt, Rh, and Rh as heterometals toward exploring the N2 catalytic activation (electronic and chemical characteristics); the monometallic surfaces are used for critical comparison in terms of their N2 activation behavior. In particular, adsorption geometries/energetics, density of states (DOS), and charge transfer are discussed. From the N2 activation on the surfaces, we could precisely capture the transition state of the N2 dissociation reaction/step. The effect of the metal alloying (geometrical and electronic factors) as well as the effect of applied mechanical strain, as a tuning factor of alloying, are both studied and thoroughly discussed. DOS studies revealed that the d-band center moved toward the negative direction for all late-TM-based alloys, thereby allowing the nitrogen molecule to adsorb weakly as compared to the early-TM surface alloys. In terms of the mechanical strain, for most of the alloy surfaces studied, apart from the Mo/Fe(110) one, the N2 binding energy varies as a linear function of the applied strain. The mechanical effect trend is in agreement with the charge transfer descending order followed: Fe/Mo(110) > Rh/Mo(110) > Au/Mo(110) > Pt/Mo(110) > Ni/Mo(110) > Ru/Mo(110) > Cu/Mo(110) > Ag/Mo(110) > Pd/Mo(110) > Au/Mo(110), pointing out that Fe-functionalized Mo(110) surface presents the highest charge transfer of -2.14 |e| to the N2 molecule. This study aspires to provide navigation criteria through the abundant design criteria of N2 activation catalysts.

Solvent‐Induced Dynamic Bond Regulation for Constructing Adaptive Lubricating Hydrogels with Switchable Tribological Performance and Environmental Adaptability

AbstractAdaptive lubricating hydrogels (ALH) show promise for reducing friction and energy consumption in various industrial applications. However, retarded switchable tribological performance and poor environmental adaptability limit their integration into application devices. Herein, a dynamic bond regulating strategy based on solvent conversion for producing an ALH with highly switchable tribological performance and decent environmental tolerance is proposed. By incorporating dynamic B─O bonds into the sodium alginate (SA) framework, these bonds transition between associative and dissociative states, facilitated by solvent conversion between glycerol and ethanol. This process modulates the mechanical modulus of the SA network, allowing for achieving highly switchable tribological performance. Furthermore, the inclusion of glycerol not only as a modulus regulator but also serves as an antifreeze component to impart the ALH with superior antifreeze and heat resistance properties, thus allowing the ALH to demonstrate excellent environmental adaptability. As a result, the resulting ALH exhibits highly switchable lubrication behavior, with a dynamically adjustable coefficient of friction (COF) between 0.022 and 0.157, and maintains consistent lubrication performance under a harsh environment (−40–60 °C), representing the state‐of‐the‐art in reported ALHs. This advancement allows for the development of intelligent brake devices (IBD), demonstrating potential applications in controlling drone speed.

Phase transition and ionic conductivity of pyrrolidinium-based ionic plastic crystals with magnesium salts

Abstract Despite being safe for use in secondary Mg batteries, solid electrolytes exhibit lower ionic conductivities than those of traditional liquid electrolytes. Organic ionic plastic crystals—soft crystals with excellent thermal and electrochemical stabilities and ionic conductivities—are promising solid electrolytes. Herein, we investigated the effects of various anion species and Mg salt concentrations on the properties of pyrrolidinium-based organic ionic plastic crystals (N,N-diethylpyrrolidinium bis(fluorosulfonyl)amide [[C2epyr][FSA]] and N,N-diethylpyrrolidinium bis(trifluoromethylsulfonyl)amide [[C2epyr][TFSA]]) upon Mg(TFSA)2 addition. The Mg-ion transference number (tMg2+) was measured using the Vincent–Bruce method; ionic conductivity via impedance measurements; and phase transition via differential scanning calorimetry. The phase transition behavior, dissociation state of the Mg salt, and electrochemical properties varied with the organic ionic plastic crystal anionic structure. The FSA system became liquid when the Mg salt concentration exceeded 15 mol%. The ionic conductivity of the pyrrolidinium-based organic ionic plastic crystals increased substantially with the Mg salt concentration. In the solid state, [C2epyr][FSA]/Mg(TFSA)2 (5 mol%) (FT5) showed the highest ionic conductivity (2.9 × 10−4 S cm−1 at 25 °C). The tMg2+ of FT5 at 60 °C was 0.29. Mg exhibited redox behavior in FT5 but not in [C2epyr][TFSA]/Mg(TFSA)2 (5 mol%). The FSA− structure is suitable for Mg electrochemistry and will aid in developing high-performance secondary Mg batteries.

Imaging study of O3 photodissociation in the Huggins band.

We report a velocity-mapped ion imaging study of the photodissociation of O3 in the Huggins band. The O(3PJ) images show evidence for three electronic channels producing O2(X3Σg-), O2(a1∆g), and O2(b1Σg+) state fragments, with the latter two arising from the spin-forbidden photodissociation of O3. Forward convolution simulations of the derived total translational energy distributions permit extraction of the vibrational state distribution for each O2 electronic state. All these distributions peak near v = 0 and decrease monotonically with the vibrational state. The wavelength-dependent branching of the three electronic channels has been determined and is approximately constant over the wavelength region studied (322-328nm). We have observed that the O2 electronic state branching ratios depend on the coincident O(3PJ) spin-orbit state, and the O2(b1Σg+) state is particularly sensitive. These results are qualitatively consistent with previous calculations on the coupling of the initially excited state to dissociative states by Rosenwaks and Grebenshchikov [J. Phys. Chem. A. 114, 9809-9819 (2010)]. The spatial anisotropy of the three dissociation channels has been determined through analysis of the O(3P0) angular distributions. The results are consistent with recent calculations but differ from previous experimental reports. The experimental results provide detailed information on the dissociation dynamics and should motivate new calculations.

Recreational ketamine use and its impact on health

Ketamine, also known as 2-(2-chlorophenyl)-2-(methylamino)-cyclohexanone, is a dissociative anesthetic that has gained popularity as a recreational substance among young people, especially in nightclubs and at parties. It acts as a noncompetitive NMDA receptor antagonist, inducing a dissociative state that manifests as catalepsy, unconsciousness and amnesia. Recreational use of ketamine and the number of illicit seizures of ketamine have increased in recent years, prompting a review of current evidence on its toxicity. Recreational ketamine use is associated with a number of toxic effects, both acute and chronic. Predominant among the acute effects are psychotic symptoms, hallucinations and aggression, which can lead to serious injuries. Chronic ketamine use leads to intractable urological problems and neuropsychiatric problems, Long-term effects also include gastrointestinal problems such as abdominal pain and liver function abnormalities. This review summarizes current evidences on the acute and chronic ketamine toxicity associated with its recreational use.