Detection of short-lasting and ictal spike-and-wave discharges in around-the-ears EEG recordings in children with absence epilepsy.

PURPOSE: Long-term ambulatory EEG recordings can improve the monitoring of absence epilepsy in children, but signal quality and increased review workload are a concern. We evaluated the feasibility of around-the-ears EEG arrays (cEEGrids) to capture 3-Hz short-lasting and ictal spike-and-wave discharges and assessed the performance of automated detection software in cEEGrids data. We compared patterns of bilateral synchronisation between short-lasting and ictal spike-and-wave discharges. METHODS: We recruited children with suspected generalised epilepsy undergoing routine video-EEG monitoring and performed simultaneous cEEGrids recordings. We used ASSYST software to detect short-lasting 3-Hz spike-and-wave discharges (1-3 s) and ictal spike-and-wave discharges in the cEEGrids data. We assessed data quality and sensitivity of cEEGrids for spike-and-wave discharges in routine EEG. We determined the sensitivity and false detection rate for automated spike-and-wave discharge detection in cEEGrids data. We compared bihemispheric synchrony across the onset of short-lasting and ictal spike-and-wave discharges using the mean phase coherence in the 2-4 Hz frequency band. RESULTS: We included nine children with absence epilepsy (median age = 11 y, range 8-15 y, nine females) and recorded 4 h and 27 min of cEEGrids data. The recordings from seven participants were suitable for quantitative analysis, containing 82 spike-and-wave discharges. The cEEGrids captured 58 % of all spike-and-wave discharges (median individual sensitivity: 100 %, range: 47-100 %). ASSYST detected 82 % of all spike-and-wave discharges (median: 100 %, range: 41-100 %) with a false detection rate of 48/h (median: 6/h, range: 0-154/h). The mean phase coherence significantly increased during short-lasting and ictal spike-and-wave discharges in the 500-ms pre-onset to 1-s post-onset interval. CONCLUSIONS: cEEGrids are of variable quality for monitoring spike-and-wave discharges in children with absence epilepsy. ASSYST could facilitate the detection of short-lasting and ictal spike-and-wave discharges with clear periodic structures but with low specificity. A similar course of bihemispheric synchrony between short-lasting and ictal spike-and-wave discharges indicates that cortico-thalamic driving may be relevant for both types of spike-and-wave discharges.

Identification of Diabetic Small-Fiber Neuropathy Based on Electrophysiological and Psychophysical Responses to Intra-Epidermal Electric Stimulation using a Naïve Bayes Classifier.

Diagnosis and stratification of small-fiber neuropathy patients is difficult due to a lack of methods that are both sensitive and specific. Our lab recently developed a method to accurately measure psychophysical and electrophysiological responses to intra-epidermal electric stimulation, specifically targeting small nerve fibers in the skin. In this work, we study whether using one or a combination of psychophysical and electrophysiological outcome measures can be used to identify diabetic small-fiber neuropathy. It was found that classification of small-fiber neuropathy based on psychophysical and electrophysiological responses to intra-epidermal electric stimulation could match or even outperform current state-of-the-art methods for the diagnosis of small-fiber neuropathy.Clinical Relevance-Neuropathy is damage or dysfunction of nerves in the skin, often leading to the development of chronic pain. Small-fiber neuropathy is the most prevalent type of neuropathy and occurs frequently in patients with diabetes mellitus, but can also occur in other diseases or in response to chemotherapy. Early detection of neuropathy could help diabetic patients to adapt glucose management, and doctors to adjust treatment strategies to prevent nerve loss and chronic pain, but is impeded by a lack of clinical tools to monitor small nerve fiber function.

Sleep spindles across youth affected by schizophrenia or anti-N-methyl-D-aspartate-receptor encephalitis.

Background: Sleep disturbances are intertwined with the progression and pathophysiology of psychotic symptoms in schizophrenia. Reductions in sleep spindles, a major electrophysiological oscillation during non-rapid eye movement sleep, have been identified in patients with schizophrenia as a potential biomarker representing the impaired integrity of the thalamocortical network. Altered glutamatergic neurotransmission within this network via a hypofunction of the N-methyl-D-aspartate receptor (NMDAR) is one of the hypotheses at the heart of schizophrenia. This pathomechanism and the symptomatology are shared by anti-NMDAR encephalitis (NMDARE), where antibodies specific to the NMDAR induce a reduction of functional NMDAR. However, sleep spindle parameters have yet to be investigated in NMDARE and a comparison of these rare patients with young individuals with schizophrenia and healthy controls (HC) is lacking. This study aims to assess and compare sleep spindles across young patients affected by Childhood-Onset Schizophrenia (COS), Early-Onset Schizophrenia, (EOS), or NMDARE and HC. Further, the potential relationship between sleep spindle parameters in COS and EOS and the duration of the disease is examined. Methods: Sleep EEG data of patients with COS (N = 17), EOS (N = 11), NMDARE (N = 8) aged 7-21 years old, and age- and sex-matched HC (N = 36) were assessed in 17 (COS, EOS) or 5 (NMDARE) electrodes. Sleep spindle parameters (sleep spindle density, maximum amplitude, and sigma power) were analyzed. Results: Central sleep spindle density, maximum amplitude, and sigma power were reduced when comparing all patients with psychosis to all HC. Between patient group comparisons showed no differences in central spindle density but lower central maximum amplitude and sigma power in patients with COS compared to patients with EOS or NMDARE. Assessing the topography of spindle density, it was significantly reduced over 15/17 electrodes in COS, 3/17 in EOS, and 0/5 in NMDARE compared to HC. In the pooled sample of COS and EOS, a longer duration of illness was associated with lower central sigma power. Conclusions: Patients with COS demonstrated more pronounced impairments of sleep spindles compared to patients with EOS and NMDARE. In this sample, there is no strong evidence that changes in NMDAR activity are related to spindle deficits.

Bubble Printing of Ti3C2TX MXene for Patterning Conductive and Plasmonic Nanostructures.

MXenes represent a novel class of 2D materials with unique properties and have great potential for diverse applications in sensing and electronics; however, their directed assembly at interfaces has not yet been achieved. Herein, the plasmonic heating of MXenes was exploited to achieve the controlled deposition of MXene assemblies via a laser-directed microbubble. The influence of various factors such as solvent composition, substrate surface chemistry, MXene concentration, and laser fluence was investigated, establishing the optimal conditions for rapid patterning with good fidelity. Printed MXene assemblies showed good electrical conductivity and plasmonic sensing capabilities and were able to meet or exceed the state of the art without additional postprocessing steps. This represents the first study of a directed approach for microfabrication using MXenes and lays the foundation for future work in optically directed assembly of MXenes and MXene-based nanocomposites at interfaces toward sensors and devices.

Transcranial magnetic stimulation-evoked electroencephalography responses as biomarkers for epilepsy: A review of study design and outcomes.

Transcranial magnetic stimulation (TMS) with electroencephalography (EEG), that is TMS-EEG, may assist in managing epilepsy. We systematically reviewed the quality of reporting and findings in TMS-EEG studies on people with epilepsy and healthy controls, and on healthy individuals taking anti-seizure medication. We searched the Cochrane Library, Embase, PubMed and Web of Science databases for original TMS-EEG studies comparing people with epilepsy and healthy controls, and healthy subjects before and after taking anti-seizure medication. Studies should involve quantitative analyses of TMS-evoked EEG responses. We evaluated the reporting of study population characteristics and TMS-EEG protocols (TMS sessions and equipment, TMS trials and EEG protocol), assessed the variation between protocols, and recorded the main TMS-EEG findings. We identified 20 articles reporting 14 unique study populations and TMS methodologies. The median reporting rate for the group of people with epilepsy parameters was 3.5/7 studies and for the TMS parameters was 13/14 studies. TMS protocols varied between studies. Fifteen out of 28 anti-seizure medication trials in total were evaluated with time-domain analyses of single-pulse TMS-EEG data. Anti-seizure medication significantly increased N45, and decreased N100 and P180 component amplitudes but in marginal numbers (N45: 8/15, N100: 7/15, P180: 6/15). Eight articles compared people with epilepsy and controls using different analyses, thus limiting comparability. The reporting quality and methodological uniformity between studies evaluating TMS-EEG as an epilepsy biomarker is poor. The inconsistent findings question the validity of TMS-EEG as an epilepsy biomarker. To demonstrate TMS-EEG clinical applicability, methodology and reporting standards are required.

Layered silicate edge-linked perylene diimides: Synthesis, self-assembly and energy transfer.

The control over intermolecular interactions between chromophores at nanomaterial interfaces is important for sensing and light-harvesting applications. To that aim, inorganic nanoparticles with anisotropic shape and surface chemistry can serve as useful supports for organic modification. Herein, novel asymmetric perylene diimides with aspartic acid and oleyl terminal groups were grafted to the edges of the layered silicate clay Laponite, a water-dispersible discoidal nanoparticle. The photophysical properties and solvent-dependent self-assembly of the nanoclay-grafted perylenes were investigated, revealing that the polarity of the terminating ligand dictates the aggregation behavior in aqueous solution, where increased water content generally led to the formation of perylene H-aggregates. The anionic basal surface of the nanoclay provided a binding site for a cationic fluorophore, leading to energy transfer from the face-bound donor to the edge-bound perylene acceptor. This study encourages further research on the use of functional ligands for the formation of organic-inorganic hybrids, particularly where inorganic template particles with specific surface chemistry can be exploited to study intermolecular interactions. Overall, these findings should advance further design and implementation of novel semiconducting ligands towards inorganic-organic hybrids, with potential applications in sensing and energy harvesting.

The Upper Juruá Extractive Reserve in the Brazilian Amazon: past and present / A Reserva Extrativista do Alto Juruá na Amazônia Brasileira: passado e presente

Amazonian livelihoods are largely dependent on rivers, with local protein consumption mainly relying on several species of fish. The UJER (Upper Juruá Extractive Reserve - Reserva Extrativista do Alto Juruá) is located in the state of Acre, bordering Peru and several indigenous areas. Here we summarize the data we collected in 1993/1994 on the population living along the banks of the Juruá, Tejo, Bagé, Igarapé São João and Breu rivers on crop cultivation, animal husbandry, and use of game and fish resources. We interviewed 133 individuals (94 on the Juruá and Tejo, 16 on Bagé, 16 on Igarapé São João and 7 on Breu rivers). Our results include a comprehensive description on local livelihoods, including the most important fish species for local subsistence considering gender and seasonality, the main husbandry and game species, and the items cultivated on the local agriculture. Whenever more recent information was available in the literature, we compared changes in livelihoods over time in the same region and also with the recent patterns observed in the Lower and in the Middle Juruá River. We hope to provide useful information to understand temporal changes in local livelihoods, which can help adapt and shape the ecological management in the region.

Comunidades da Amazônia são amplamente dependentes dos rios, com o consumo local de alimentos baseado em várias espécies de peixes. A UJER (Reserva Extrativista do Alto Juruá - Reserva Extrativista do Alto Juruá) está localizada no estado do Acre, na fronteira com o Peru e com várias áreas indígenas. Aqui resumimos os dados que coletamos em 1993/1994 da população que vive às margens dos rios Juruá, Tejo, Bagé, Igarapé São João e Breu sobre cultivo, criação de animais e uso de recursos de caça e peixes. Foram entrevistados 133 indivíduos (94 nos rios Juruá e Tejo, 16 em Bagé, 16 em Igarapé São João e 7 no rio Breu). Nossos resultados incluem uma descrição abrangente dos meios de subsistência locais, incluindo as espécies de peixes mais importantes para a subsistência local, considerando gênero e sazonalidade, bem como as principais espécies de criação, de caça e os itens cultivados na agricultura local., Quando foi possível obter informações da literatura, comparamos as mudanças nos meios de subsistência ao longo do tempo na mesma região e também com os padrões recentes observados no Baixo e no Médio Rio Juruá. Esperamos fornecer informações úteis para o entendimento das mudanças temporais nos meios de subsistência locais, o que pode ser útil ao manejo ecológico da região.

The Upper Juruá Extractive Reserve in the Brazilian Amazon: past and present

Abstract Amazonian livelihoods are largely dependent on rivers, with local protein consumption mainly relying on several species of fish. The UJER (Upper Juruá Extractive Reserve - Reserva Extrativista do Alto Juruá) is located in the state of Acre, bordering Peru and several indigenous areas. Here we summarize the data we collected in 1993/1994 on the population living along the banks of the Juruá, Tejo, Bagé, Igarapé São João and Breu rivers on crop cultivation, animal husbandry, and use of game and fish resources. We interviewed 133 individuals (94 on the Juruá and Tejo, 16 on Bagé, 16 on Igarapé São João and 7 on Breu rivers). Our results include a comprehensive description on local livelihoods, including the most important fish species for local subsistence considering gender and seasonality, the main husbandry and game species, and the items cultivated on the local agriculture. Whenever more recent information was available in the literature, we compared changes in livelihoods over time in the same region and also with the recent patterns observed in the Lower and in the Middle Juruá River. We hope to provide useful information to understand temporal changes in local livelihoods, which can help adapt and shape the ecological management in the region.

Resumo Comunidades da Amazônia são amplamente dependentes dos rios, com o consumo local de alimentos baseado em várias espécies de peixes. A UJER (Reserva Extrativista do Alto Juruá - Reserva Extrativista do Alto Juruá) está localizada no estado do Acre, na fronteira com o Peru e com várias áreas indígenas. Aqui resumimos os dados que coletamos em 1993/1994 da população que vive às margens dos rios Juruá, Tejo, Bagé, Igarapé São João e Breu sobre cultivo, criação de animais e uso de recursos de caça e peixes. Foram entrevistados 133 indivíduos (94 nos rios Juruá e Tejo, 16 em Bagé, 16 em Igarapé São João e 7 no rio Breu). Nossos resultados incluem uma descrição abrangente dos meios de subsistência locais, incluindo as espécies de peixes mais importantes para a subsistência local, considerando gênero e sazonalidade, bem como as principais espécies de criação, de caça e os itens cultivados na agricultura local., Quando foi possível obter informações da literatura, comparamos as mudanças nos meios de subsistência ao longo do tempo na mesma região e também com os padrões recentes observados no Baixo e no Médio Rio Juruá. Esperamos fornecer informações úteis para o entendimento das mudanças temporais nos meios de subsistência locais, o que pode ser útil ao manejo ecológico da região.

The Upper Juruá Extractive Reserve in the Brazilian Amazon: past and present / A Reserva Extrativista do Alto Juruá na Amazônia Brasileira: passado e presente

Amazonian livelihoods are largely dependent on rivers, with local protein consumption mainly relying on several species of fish. The UJER (Upper Juruá Extractive Reserve - Reserva Extrativista do Alto Juruá) is located in the state of Acre, bordering Peru and several indigenous areas. Here we summarize the data we collected in 1993/1994 on the population living along the banks of the Juruá, Tejo, Bagé, Igarapé São João and Breu rivers on crop cultivation, animal husbandry, and use of game and fish resources. We interviewed 133 individuals (94 on the Juruá and Tejo, 16 on Bagé, 16 on Igarapé São João and 7 on Breu rivers). Our results include a comprehensive description on local livelihoods, including the most important fish species for local subsistence considering gender and seasonality, the main husbandry and game species, and the items cultivated on the local agriculture. Whenever more recent information was available in the literature, we compared changes in livelihoods over time in the same region and also with the recent patterns observed in the Lower and in the Middle Juruá River. We hope to provide useful information to understand temporal changes in local livelihoods, which can help adapt and shape the ecological management in the region.

Comunidades da Amazônia são amplamente dependentes dos rios, com o consumo local de alimentos baseado em várias espécies de peixes. A UJER (Reserva Extrativista do Alto Juruá - Reserva Extrativista do Alto Juruá) está localizada no estado do Acre, na fronteira com o Peru e com várias áreas indígenas. Aqui resumimos os dados que coletamos em 1993/1994 da população que vive às margens dos rios Juruá, Tejo, Bagé, Igarapé São João e Breu sobre cultivo, criação de animais e uso de recursos de caça e peixes. Foram entrevistados 133 indivíduos (94 nos rios Juruá e Tejo, 16 em Bagé, 16 em Igarapé São João e 7 no rio Breu). Nossos resultados incluem uma descrição abrangente dos meios de subsistência locais, incluindo as espécies de peixes mais importantes para a subsistência local, considerando gênero e sazonalidade, bem como as principais espécies de criação, de caça e os itens cultivados na agricultura local. Quando foi possível obter informações da literatura, comparamos as mudanças nos meios de subsistência ao longo do tempo na mesma região e também com os padrões recentes observados no Baixo e no Médio Rio Juruá. Esperamos fornecer informações úteis para o entendimento das mudanças temporais nos meios de subsistência locais, o que pode ser útil ao manejo ecológico da região.

Exploring Nociceptive Detection Thresholds Combined with Evoked Potentials in Patients with Diabetes Mellitus.

There is a lack of diagnostic tools that can objectively measure small fiber neuropathy (SFN) in patients with diabetes mellitus (DM). Recently, nociceptive nerve function was observed by nociceptive detection thresholds (NDTs) and brain evoked potentials (EPs) during intra-epidermal electrical stimulation (IES) targeting Aδ-fibers. In this proof of principle, we studied whether it is possible to measure NDTs combined with EPs in DM patients with and without neuropathic pain. Furthermore, we explored the sensitivity of NDTs and EPs for polyneuropathy in these patients. Five DM patients diagnosed with painful neuropathy (DMp), five DM patients without painful neuropathy (DM), and five healthy controls (HC) were analyzed. These preliminary results showed that we can accurately measure NDTs and EPs in patients with diabetes. Strikingly, increased NDTs were found in DM and DMp compared to HC, of which the DMp showed the largest NDTs. This suggests that NDTs during IES could be a powerful biomarker for monitoring peripheral dysfunctions. Current EEG data of patients did not show any significant differences. The population needs to be enlarged before we can investigate the sensitivity of these NDTs and EPs to diabetic polyneuropathy and associated changes in nociceptive processing in more detail.Clinical Relevance- This proof of principle in a small group of patients with diabetes mellitus potentially treats the observation of the loss of nociceptive function occurring with small fiber neuropathy. That helps the development of a diagnostic measure to monitor future (early-stage) nociceptive dysfunctions in a clinical environment.

The Upper Juruá Extractive Reserve in the Brazilian Amazon: past and present†.

Amazonian livelihoods are largely dependent on rivers, with local protein consumption mainly relying on several species of fish. The UJER (Upper Juruá Extractive Reserve - Reserva Extrativista do Alto Juruá) is located in the state of Acre, bordering Peru and several indigenous areas. Here we summarize the data we collected in 1993/1994 on the population living along the banks of the Juruá, Tejo, Bagé, Igarapé São João and Breu rivers on crop cultivation, animal husbandry, and use of game and fish resources. We interviewed 133 individuals (94 on the Juruá and Tejo, 16 on Bagé, 16 on Igarapé São João and 7 on Breu rivers). Our results include a comprehensive description on local livelihoods, including the most important fish species for local subsistence considering gender and seasonality, the main husbandry and game species, and the items cultivated on the local agriculture. Whenever more recent information was available in the literature, we compared changes in livelihoods over time in the same region and also with the recent patterns observed in the Lower and in the Middle Juruá River. We hope to provide useful information to understand temporal changes in local livelihoods, which can help adapt and shape the ecological management in the region.

Altered EEG markers of synaptic plasticity in a human model of NMDA receptor deficiency: Anti-NMDA receptor encephalitis.

Plasticity of synaptic strength and density is a vital mechanism enabling memory consolidation, learning, and neurodevelopment. It is strongly dependent on the intact function of N-Methyl-d-Aspartate Receptors (NMDAR). The importance of NMDAR is further evident as their dysfunction is involved in many diseases such as schizophrenia, Alzheimer's disease, neurodevelopmental disorders, and epilepsies. Synaptic plasticity is thought to be reflected by changes of sleep slow wave slopes across the night, namely higher slopes after wakefulness at the beginning of sleep than after a night of sleep. Hence, a functional NMDAR deficiency should theoretically lead to altered overnight changes of slow wave slopes. Here we investigated whether pediatric patients with anti-NMDAR encephalitis, being a very rare but unique human model of NMDAR deficiency due to autoantibodies against receptor subunits, indeed show alterations in this sleep EEG marker for synaptic plasticity. We retrospectively analyzed 12 whole-night EEGs of 9 patients (age 4.3-20.8 years, 7 females) and compared them to a control group of 45 healthy individuals with the same age distribution. Slow wave slopes were calculated for the first and last hour of Non-Rapid Eye Movement (NREM) sleep (factor 'hour') for patients and controls (factor 'group'). There was a significant interaction between 'hour' and 'group' (p = 0.013), with patients showing a smaller overnight decrease of slow wave slopes than controls. Moreover, we found smaller slopes during the first hour in patients (p = 0.022), whereas there was no group difference during the last hour of NREM sleep (p = 0.980). Importantly, the distribution of sleep stages was not different between the groups, and in our main analyses of patients without severe disturbance of sleep architecture, neither was the incidence of slow waves. These possible confounders could therefore not account for the differences in the slow wave slope values, which we also saw in the analysis of the whole sample of EEGs. These results suggest that quantitative EEG analysis of slow wave characteristics may reveal impaired synaptic plasticity in patients with anti-NMDAR encephalitis, a human model of functional NMDAR deficiency. Thus, in the future, the changes of sleep slow wave slopes may contribute to the development of electrophysiological biomarkers of functional NMDAR deficiency and synaptic plasticity in general.

Photoinduced Intramolecular Electron Transfer in Phenylene Ethynylene Naphthalimide Oligomers.

This paper reports a photophysical investigation of a series of phenylene ethynylene oligomers (OPE) that are end-substituted with a 1,8-naphthalene imide (NI) acceptor. The NI acceptor is attached to the terminus of the OPEs via an ethynylene (-C≡C-) unit that is linked at the 4-position of the NI unit. A series of three oligomers is investigated, OPE1-NI, OPE3-NI, and OPE5-NI, which contain 1, 3, and 5 phenylene ethynylene repeat units, respectively. The properties of the OPEn-NI series are compared to a corresponding set of unsubstituted OPEs, OPE3 and OPE5, which contain 3 and 5 phenylene ethynylene repeats, respectively. The photophysics of all the compounds are interrogated using a variety of techniques including steady-state absorption, steady-state fluorescence, two-photon absorption, time-resolved fluorescence, and transient absorption spectroscopy on femtosecond-to-microsecond time scales. The effect of solvent polarity on the properties of the oligomers is examined. The results show that the NI-substituted oligomers feature a lowest charge transfer (CT) excited state, where the OPE segment acts as the donor and the NI moiety is the acceptor (OPEn•+-NI•-). The absorption spectra in one-photon and two-photon exhibit a clear manifold of absorption features that can be attributed to direct CT absorption. In moderately polar solvents, the emission is dominated by a broad, solvatochromic band that is due to radiative decay from the CT excited state. Ultrafast transient absorption provides evidence for initial population of a locally excited state (LE) which in moderately polar solvents rapidly (∼1 ps) evolves into the CT excited state. The structure, spectroscopy, and dynamics of the CT state are qualitatively similar for OPE3-NI and OPE5-NI, suggesting that delocalization in the OPE segment does not have much effect on the structure or energetics of the CT excited state.

Ultrafast Excited-State Dynamics in trans-(N-Heterocyclic carbene)platinum(II) Acetylide Complexes.

This study probes femto- and picosecond excited-state dynamics of a series of N-heterocyclic carbene (NHC) ligand-containing platinum(II) complexes of the type trans-(NHC)2PtII(CC-Ar)2, where CC-Ar is an arylacetylide. By using femtosecond transient absorption spectroscopy, two dynamic processes are observed: an ultrafast singlet → triplet intersystem crossing (<0.3 ps), followed by geometric/electronic relaxation that takes place on a 2-10 ps time scale. The geometric/electronic relaxation is attributed to ligand torsional modes, mainly arising from twisting of the aryl units relative to the square-planar PtL4 unit. The dynamics of this relaxation process depend somewhat on steric constraints induced by substituent groups attached to the (benz)imidazole and phenyl ligands. The geometric relaxation dynamics slow with increasing solvent viscosity. The experimental studies also reveal that the different conformers can be photoselected by varying the excitation at different near-UV wavelengths. To corroborate the experimental findings, density functional theory calculations were conducted to probe the effects of geometry and steric hindrance on the ground-state energy surface. The calculations suggest that the barrier for torsion of the CC-Ar units increases as N-substituents on the NHC ligands increase in the order CH3 < cyclohexyl < n-butyl and as the CC-Ar units are substituted in the 3 and 5 positions with tert-butyl groups.

Aggregation-Enhanced Two-Photon Absorption of Anionic Conjugated Polyelectrolytes.

The two-photon absorption properties of anionic poly(phenylene ethynylene)-type conjugated oligo- and polyelectrolytes are studied in molecularly dissolved and aggregated forms in aqueous solution. Several different polyvalent cations are used to induce aggregation. It is found that both materials in the aggregated form exhibit enhanced two-photon excited fluorescence (2PEF) and two-photon cross section (σ2) compared with the molecularly dissolved structures. The 2PEF and σ2 are unaffected by the nature of the polyvalent cation that is used to induce aggregation. The two-photon absorption cross section enhancement arises because of the increase in the difference dipole moment (Δµ) in the aggregates of the conjugated materials, an effect that is attributed to the introduction of charge transfer character into the aggregate excited state.

Pre-Movement Cortico-Muscular Dynamics Underlying Improved Parkinson Gait Initiation after Instructed Arm Swing.

BACKGROUND: The supplementary motor area (SMA) is implicated in both motor initiation and stereotypic multi-limb movements such as walking with arm swing. Gait in Parkinson's disease exhibits starting difficulties and reduced arm swing, consistent with reduced SMA activity. OBJECTIVE: We tested whether enhanced arm swing could improve Parkinson gait initiation and assessed whether increased SMA activity during preparation might facilitate such improvement. METHODS: Effects of instructed arm swing on cortical activity, muscle activity and kinematics were assessed by ambulant EEG, EMG, accelerometers and video in 17 Parkinson patients and 19 controls. At baseline, all participants repeatedly started walking after a simple auditory cue. Next, patients started walking at this cue, which now meant starting with enhanced arm swing. EEG changes over the putative SMA and leg motor cortex were assessed by event related spectral perturbation (ERSP) analysis of recordings at Fz and Cz. RESULTS: Over the putative SMA location (Fz), natural PD gait initiation showed enhanced alpha/theta synchronization around the auditory cue, and reduced alpha/beta desynchronization during gait preparation and movement onset, compared to controls. Leg muscle activity in patients was reduced during preparation and movement onset, while the latter was delayed compared to controls. When starting with enhanced arm swing, these group differences virtually disappeared. CONCLUSION: Instructed arm swing improves Parkinson gait initiation. ERSP normalization around the cue indicates that the attributed information may serve as a semi-internal cue, recruiting an internalized motor program to overcome initiation difficulties.

Sleep slow-wave homeostasis and cognitive functioning in children with electrical status epilepticus in sleep.

STUDY OBJECTIVES: Encephalopathy with electrical status epilepticus in sleep (ESES) is characterized by non-rapid eye movement (non-REM)-sleep-induced epileptiform activity and acquired cognitive deficits. The synaptic homeostasis hypothesis describes the process of daytime synaptic potentiation balanced by synaptic downscaling in non-REM-sleep and is considered crucial to retain an efficient cortical network. We aimed to study the overnight decline of slow waves, an indirect marker of synaptic downscaling, in patients with ESES and explore whether altered downscaling relates to neurodevelopmental and behavioral problems. METHODS: Retrospective study of patients with ESES with at least one whole-night electroencephalogram (EEG) and neuropsychological assessment (NPA) within 4 months. Slow waves in the first and last hour of non-REM-sleep were analyzed. Differences in slow-wave slope (SWS) and overnight slope course between the epileptic focus and non-focus electrodes and relations to neurodevelopment and behavior were analyzed. RESULTS: A total of 29 patients with 44 EEG ~ NPA combinations were included. Mean SWS decreased from 357 to 327 µV/s (-8%, p < 0.001) across the night and the overnight decrease was less pronounced in epileptic focus than in non-focus electrodes (-5.6% vs. -8.7%, p = 0.003). We found no relation between SWS and neurodevelopmental test results in cross-sectional and longitudinal analyses. Patients with behavioral problems showed less SWS decline than patients without and the difference was most striking in the epileptic focus (-0.9% vs. -8.8%, p = 0.006). CONCLUSIONS: Slow-wave homeostasis-a marker of synaptic homeostasis-is disturbed by epileptiform activity in ESES. Behavioral problems, but not neurodevelopmental test results, were related to severity of this disturbance.

Stereochemical Effects on Platinum Acetylide Two-Photon Chromophores.

A series of cis-platinum(II) acetylide complexes containing two-photon-absorbing chromophores have been synthesized and characterized to explore the effects of stereochemistry on the nonlinear absorption properties. The molecules feature 4-(phenylethynyl)phenylethynylene (PE2), diphenylaminofluorene (DPAF), and benzothiazolylfluorene (BTF) ligands. The photophysical properties were investigated under one- and two-photon conditions and compared to the known trans analogues via UV-visible absorption, photoluminescence, femtosecond and nanosecond transient absorption (TA), nanosecond z-scan, and femtosecond two-photon absorption (2PA). The bent cis complexes exhibit blue shifts in the absorption, emission, femtosecond, and nanosecond TA spectra along with lower molar extinction coefficients and lower phosphorescence yields relative to the trans complexes suggesting less efficient Pt-induced spin-orbit coupling and intersystem crossing in the cis configuration. The cis chromophores are noncentrosymmetric and therefore show dipolar behavior with a pronounced 2PA in the 0-0 transition of the S0 → S1 band, while the trans complexes show quadrupolar behavior with a forbidden 0-0 transition. In the S0 → Sn region, both cis and trans complexes show intense two-photon-absorption bands (up to 3700 GM by the peak cross section for cis-BTF) which contain a significant contribution from the excited state absorption (S1 → Sn). All six complexes exhibit comparable nonlinear absorption response with a significant contribution from triplet-triplet absorption that slightly favors trans complexes but is more strongly dependent upon the structure of the π-conjugated chromophore.

Blue Phosphorescent trans-N-Heterocyclic Carbene Platinum Acetylides: Dependence on Energy Gap and Conformation.

A series of 11 complexes of the type trans-(NHC)2Pt(CC-Ar)2 (where NHC = N-heterocyclic carbene) have been synthesized and their photophysics characterized. The complexes display moderately efficient deep blue to green phosphorescence from a triplet excited state that is localized mainly in the aryl acetylide ligand (CC-Ar). The emission energy varies with the substituent on CC-Ar, with the highest energy emission for Ar = 4-pyridyl. The emission quantum efficiency and lifetime for the series decreases with increasing emission energy (Eem), and the effect is identified as arising from an increase in the nonradiative decay rate (knr) with Eem. Temperature-dependent emission lifetime studies for three complexes give activation energies for the nonradiative decay process ∼1000 cm-1, and the thermally activated decay process is attributed to crossing to a nonemissive metal-centered (d-d) excited state. At a low temperature, two different emission progressions are observed. Density functional theory calculations suggest that the triplet energy varies with the torsion of the aryl acetylide rings relative to the plane defined by the PtC4 unit (where C = the carbon atoms bonded to Pt). The multiple emission is ascribed to emission from complexes differing with respect to the aryl acetylide ring torsion. Ultrafast transient absorption spectroscopy reveals a fast relaxation (∼5 ps) that may also be due to aryl acetylide ring torsional relaxation in the triplet excited state.