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Cost-efficient and easily integrable broadband mid-infrared (mid-IR) sources would significantly enhance the application space of photonic integrated circuits (PICs). Thermal incandescent sources are superior to other common mid-IR emitters based on semiconductor materials in terms of PIC compatibility, manufacturing costs, and bandwidth. Ideal thermal emitters would radiate directly into the desired modes of the PIC waveguides via near-field coupling and would be stable at very high temperatures. Graphene is a semimetallic two-dimensional material with comparable emissivity to thin metallic thermal emitters. It allows maximum coupling into waveguides by placing it directly into their evanescent fields. Here, we demonstrate graphene mid-IR emitters integrated with photonic waveguides that couple directly into the fundamental mode of silicon waveguides designed to work in the so-called "fingerprint region" relevant for gas sensing. High broadband emission intensity is observed at the waveguide-integrated graphene emitter. The emission at the output grating couplers confirms successful coupling into the waveguide mode. Thermal simulations predict emitter temperatures up to 1000 °C, where the blackbody radiation covers the mid-IR region. A coupling efficiency η, defined as the light emitted into the waveguide divided by the total emission, of up to 68% is estimated, superior to data published for other waveguide-integrated emitters.
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BACKGROUND: Neurogenic overactive bladder (OAB) is a distressing condition in stroke. Existing neurogenic OAB management is expensive, unstandardized regimens, or invasive. Evaluating the effectiveness of repetitive transcranial magnetic stimulation (rTMS) remains crucial. We aimed to (1) compare the effectiveness of active-rTMS with sham-rTMS on neurogenic OAB symptoms, (2) analyze whether rTMS is cost-effective, and (3) explore the rTMS's experiences on participants' symptoms. METHODS: This is a randomized, sham-controlled, double-blinded trial with embedded qualitative and cost-effectiveness studies. A total of 110 stroke survivors with neurogenic OAB symptoms were screened for eligibility; 60 participants were eligible for inclusion and were randomly assigned to either the active (n = 30) or sham-rTMS (n = 30) groups using a computer-generated randomization schedule. The active-rTMS group received low-frequency rTMS of 1200 pulses per session lasting 20 min thrice weekly to pelvic floor muscle representation at the contralesional primary motor cortex. The sham-rTMS group received low-frequency stimulation at a 20 % resting motor threshold using the same coil as the active-rTMS but was configured to reduce the TMS-induced electrical fields significantly. The primary and secondary outcome measures were assessed at baseline, post-intervention (week 4) and follow-up (week 8). The analysis of covariance (ANCOVA) analysis compared changes in the study groups. Quality-adjusted life-years (QALY) were measured to evaluate the cost-effectiveness while EQ-5D-5L estimated QALY changes. Additionally, the focus group discussion data were thematically analyzed. CONCLUSIONS: The findings from this rTMS intervention study will be useful in alleviating neurogenic OAB symptoms and enhancing patient satisfaction in a cost-effective way.
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Acidente Vascular Cerebral , Estimulação Magnética Transcraniana , Bexiga Urinária Hiperativa , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise Custo-Benefício , Método Duplo-Cego , Acidente Vascular Cerebral/complicações , Estimulação Magnética Transcraniana/métodos , Estimulação Magnética Transcraniana/economia , Resultado do Tratamento , Bexiga Urinaria Neurogênica/terapia , Bexiga Urinária Hiperativa/terapiaRESUMO
Predicting repetitive transcranial magnetic stimulation (rTMS) treatment outcomes in major depressive disorder (MDD) could reduce the financial and psychological risks of treatment failure. We systematically reviewed and meta-analyzed studies that leveraged neurophysiological and neuroimaging markers to predict rTMS response in MDD. Five databases were searched from inception to May 25, 2023. The primary meta-analytic outcome was predictive accuracy pooled from classification models. Regression models were summarized qualitatively. A promising marker was identified if it showed a sensitivity and specificity of 80% or higher in at least two independent studies. Searching yielded 36 studies. Twenty-two classification modeling studies produced an estimated area under the summary receiver operating characteristic curve of 0.87 (95% CI = 0.83-0.92), with 86.8% sensitivity (95% CI = 80.6-91.2%) and 81.9% specificity (95% CI = 76.1-86.4%). Frontal theta cordance measured by electroencephalography is closest to proof of concept. Predicting rTMS response using neurophysiological and neuroimaging markers is promising for clinical decision-making. However, replications by different research groups are needed to establish rigorous markers.
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Transtorno Depressivo Maior , Neuroimagem , Estimulação Magnética Transcraniana , Humanos , Transtorno Depressivo Maior/terapia , Transtorno Depressivo Maior/diagnóstico por imagem , Transtorno Depressivo Maior/fisiopatologia , Eletroencefalografia , Resultado do TratamentoRESUMO
Sex differences have been claimed an imperative factor in the optimization of psychiatric treatments. Intermittent theta-burst stimulation (iTBS), a patterned form of repetitive transcranial magnetic stimulation, is a promising non-invasive treatment option. Here, we investigated whether the real-time neural response to iTBS differs between men and women, and which mechanisms may mediate these differences. To this end, we capitalized on a concurrent iTBS/functional near-infrared spectroscopy setup over the left dorsolateral prefrontal cortex, a common clinical target, to test our assumptions. In a series of experiments, we show (1) a biological sex difference in absolute hemoglobin concentrations in the left dorsolateral prefrontal cortex in healthy participants; (2) that this sex difference is amplified by iTBS but not by cognitive tasks; and (3) that the sex difference amplified by iTBS is modulated by stimulation intensity. These results inform future stimulation treatment optimizations towards precision psychiatry.
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Córtex Pré-Frontal Dorsolateral , Espectroscopia de Luz Próxima ao Infravermelho , Estimulação Magnética Transcraniana , Humanos , Estimulação Magnética Transcraniana/métodos , Feminino , Masculino , Adulto , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Adulto Jovem , Córtex Pré-Frontal Dorsolateral/fisiologia , Caracteres SexuaisRESUMO
This systematic review investigates how prefrontal transcranial magnetic stimulation (TMS) immediately influences neuronal excitability based on oxygenation changes measured by functional magnetic resonance imaging (fMRI) or functional near-infrared spectroscopy (fNIRS). A thorough understanding of TMS-induced excitability changes may enable clinicians to adjust TMS parameters and optimize treatment plans proactively. Five databases were searched for human studies evaluating brain excitability using concurrent TMS/fMRI or TMS/fNIRS. Thirty-seven studies (13 concurrent TMS/fNIRS studies, 24 concurrent TMS/fMRI studies) were included in a qualitative synthesis. Despite methodological inconsistencies, a distinct pattern of activated nodes in the frontoparietal central executive network, the cingulo-opercular salience network, and the default-mode network emerged. The activated nodes included the prefrontal cortex (particularly dorsolateral prefrontal cortex), insula cortex, striatal regions (especially caudate, putamen), anterior cingulate cortex, and thalamus. High-frequency repetitive TMS most consistently induced expected facilitatory effects in these brain regions. However, varied stimulation parameters (e.g., intensity, coil orientation, target sites) and the inter- and intra-individual variability of brain state contribute to the observed heterogeneity of target excitability and co-activated regions. Given the considerable methodological and individual variability across the limited evidence, conclusions should be drawn with caution.
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Imageamento por Ressonância Magnética , Córtex Pré-Frontal , Estimulação Magnética Transcraniana , Humanos , Estimulação Magnética Transcraniana/métodos , Córtex Pré-Frontal/fisiologia , Córtex Pré-Frontal/diagnóstico por imagem , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Oxigênio/sangue , Mapeamento Encefálico/métodos , Encéfalo/fisiologiaAssuntos
Transtornos de Estresse Pós-Traumáticos , Estimulação Transcraniana por Corrente Contínua , Humanos , Transtornos de Estresse Pós-Traumáticos/terapia , Transtornos de Estresse Pós-Traumáticos/psicologia , Transtornos de Estresse Pós-Traumáticos/etiologia , Estimulação Transcraniana por Corrente Contínua/métodos , Feminino , Resultado do Tratamento , Delitos Sexuais/psicologia , AdultoRESUMO
Self-reported sexual orientation of transgender individuals occasionally changes over transition. Using functional magnetic resonance imaging, we tested the hypothesis that neural and behavioral patterns of sexual arousal in transgender individuals would shift from the assigned to the experienced gender (e.g., trans women's responses becoming more dissimilar to those of cis men and more similar to those of cis women). To this aim, trans women (N = 12) and trans men (N = 20) as well as cisgender women (N = 24) and cisgender men (N = 14) rated visual stimuli showing male-female, female-female or male-male intercourse for sexual arousal before and after four months of gender-affirming hormone therapy. A Bayesian framework allowed us to incorporate previous behavioral findings. The hypothesized changes could indeed be observed in the behavioral responses with the strongest results for trans men and female-female scenes. Activation of the ventral striatum supported our hypothesis only for female-female scenes in trans women. The respective application or depletion of androgens in trans men and trans women might partly explain this observation. The prominent role of female-female stimuli might be based on the differential responses they elicit in cis women and men or, in theory, the controversial concept of autogynephilia. We show that correlates of sexual arousal in transgender individuals might change in the direction of the experienced gender. Future investigations should elucidate the mechanistic role of sex hormones and the cause of the differential neural and behavioral findings.The study was registered at ClinicalTrials.gov (NCT02715232), March 22, 2016.
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Teorema de Bayes , Disforia de Gênero , Imageamento por Ressonância Magnética , Excitação Sexual , Pessoas Transgênero , Humanos , Masculino , Feminino , Adulto , Disforia de Gênero/psicologia , Disforia de Gênero/tratamento farmacológico , Pessoas Transgênero/psicologia , Comportamento Sexual/efeitos dos fármacos , Comportamento Sexual/psicologia , Adulto Jovem , Estriado Ventral/efeitos dos fármacos , Estriado Ventral/diagnóstico por imagemRESUMO
OBJECTIVES: To systematically evaluate the evidence describing the psychometric properties of clinical measures for assessing overactive bladder symptoms (urinary urgency with or without urge urinary incontinence, urinary frequency and nocturia). To evaluate the quality of this evidence-base using the COnsensus-based Standards for selecting health status Measurement INstruments (COSMIN) checklist and the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) tools. DATA SOURCES: Five electronic databases (CINAHL, EMBASE, MEDLINE, Scopus and Web of Science) were searched from dataset inception to August 2023. REVIEW METHODS: Study screening, data extraction and quality appraisal were performed by two independent authors. Inclusion criteria were studies testing one or more psychometric properties of clinical tools for the assessment of overactive bladder symptoms among adults aged 18 years and older for both sexes. The methodological quality and quality of the evidence were evaluated using the COSMIN checklist and GRADE tools, respectively. RESULTS: The search identified 40 studies totalling 10,634 participants evaluating the psychometric properties of 15 clinical tools. The COSMIN methodological quality was rated good for most measures, and the GRADE quality of evidence ranged from low (13%) to high (33%). The Overactive Bladder Symptom Score, Overactive Bladder Questionnaire and Neurogenic Bladder Symptom Score were of good methodological and high-GRADE evidence qualities. CONCLUSION: Overactive Bladder Symptom Score, the Overactive Bladder Questionnaire and the Neurogenic Bladder Symptoms Score are promising psychometrically sound measures. The Overactive Bladder Symptom Score has been applied to the most culturally diverse populations supported by studies of good methodological and high-GRADE evidence quality.
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Psicometria , Bexiga Urinária Hiperativa , Humanos , Bexiga Urinária Hiperativa/diagnóstico , Índice de Gravidade de Doença , Feminino , Masculino , Inquéritos e QuestionáriosRESUMO
OBJECTIVE: Progressive hepatic fibrosis can be considered the final stage of chronic liver disease. Hepatic stellate cells (HSC) play a central role in liver fibrogenesis. Thyroid hormones (TH, e.g. thyroxine; T4 and triiodothyronine; T3) significantly affect development, growth, cell differentiation and metabolism through activation of TH receptor α and/or ß (TRα/ß). Here, we evaluated the influence of TH in hepatic fibrogenesis. DESIGN: Human liver tissue was obtained from explanted livers following transplantation. TRα-deficient (TRα-KO) and wild-type (WT) mice were fed a control or a profibrogenic methionine-choline deficient (MCD) diet. Liver tissue was assessed by qRT-PCR for fibrogenic gene expression. In vitro, HSC were treated with TGFß in the presence or absence of T3. HSC with stable TRα knockdown and TRα deficient mouse embryonic fibroblasts (MEF) were used to determine receptor-specific function. Activation of HSC and MEF was assessed using the wound healing assay, Western blotting, and qRT-PCR. RESULTS: TRα and TRß expression is downregulated in the liver during hepatic fibrogenesis in humans and mice. TRα represents the dominant isoform in HSC. In vitro, T3 blunted TGFß-induced expression of fibrogenic genes in HSC and abrogated wound healing by modulating TGFß signalling, which depended on TRα presence. In vivo, TRα-KO enhanced MCD diet-induced liver fibrogenesis. CONCLUSION: These observations indicate that TH action in non-parenchymal cells is highly relevant. The interaction of TRα with TH regulates the phenotype of HSC via the TGFß signalling pathway. Thus, the TH-TR axis may be a valuable target for future therapy of liver fibrosis.
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Fibroblastos , Células Estreladas do Fígado , Animais , Camundongos , Humanos , Células Estreladas do Fígado/metabolismo , Hormônios Tireóideos/metabolismo , Hormônios Tireóideos/farmacologia , Receptores alfa dos Hormônios Tireóideos/genética , Receptores alfa dos Hormônios Tireóideos/metabolismo , Fator de Crescimento Transformador betaRESUMO
Low-intensity transcranial ultrasound stimulation (LITUS) is a novel non-invasive neuromodulation technique. We conducted a systematic review to evaluate current evidence on the efficacy and safety of LITUS neuromodulation. Five databases were searched from inception to May 31, 2023. Randomized controlled human trials and controlled animal studies were included. The neuromodulation effects of LITUS on clinical or pre-clinical, neurophysiological, neuroimaging, histological and biochemical outcomes, and adverse events were summarized. In total, 11 human studies and 44 animal studies were identified. LITUS demonstrated therapeutic efficacy in neurological disorders, psychiatric disorders, pain, sleep disorders and hypertension. LITUS-related changes in neuronal structure and cortical activity were found. From histological and biochemical perspectives, prominent findings included suppressing the inflammatory response and facilitating neurogenesis. No adverse effects were reported in controlled animal studies included in our review, while reversible headache, nausea, and vomiting were reported in a few human subjects. Overall, LITUS alleviates various symptoms and modulates associated brain circuits without major side effects. Future research needs to establish a solid therapeutic framework for LITUS.
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Encéfalo , Estimulação Transcraniana por Corrente Contínua , Animais , Humanos , Encéfalo/fisiologia , Estimulação Magnética Transcraniana/métodos , Animais de Laboratório , Neuroimagem , Dor , Estimulação Transcraniana por Corrente Contínua/métodosRESUMO
OBJECTIVE: To identify psychometrically robust quality-of-life (QOL) outcome measures for evaluating QOL among people with neurogenic overactive bladder (OAB). STUDY DESIGN: Electronic databases (CINAHL, EMBASE, MEDLINE, Scopus and Web of Science) were searched from inception to January 2023. Two independent reviewers participated in study screening, data extraction and quality appraisal. Studies were included if they validated at least one psychometric property of a QOL outcome measure among adults (age ≥ 18 years) with neurogenic OAB. The COnsensus-based Standards for selecting health status Measurement INstruments (COSMIN) checklist and Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) tool were used to evaluate the methodological quality and quality of evidence, respectively, for each included study. RESULTS: Database searches identified 47 studies that tested the psychometric properties of 15 QOL measures in a total of 19,994 participants with stroke, spinal cord injury, Parkinson's disease or multiple sclerosis. The Incontinence Quality of Life Questionnaire (I-QOL), King's Health Questionnaire, Overactive Bladder Questionnaire and Qualiveen were the best validated measures, with strong reliability, validity and responsiveness. I-QOL was the most robust, cross-culturally administered and psychometrically strong measure. The COSMIN checklist indicated sufficient methodological quality for 70% of measures, and the modified GRADE tool indicated quality of evidence ranging from moderate (67%) to high (33%). CONCLUSIONS: This review identified the I-QOL as a culturally diverse measure with robust reliability, validity and responsiveness for assessing QOL among people with neurogenic OAB. These findings are supported by studies with good methodological quality (COSMIN) and high-quality evidence (GRADE).
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Qualidade de Vida , Bexiga Urinária Hiperativa , Adulto , Humanos , Adolescente , Psicometria , Reprodutibilidade dos Testes , Nível de SaúdeRESUMO
BACKGROUND: Scalp stimulation has gained more traction for post-stroke cognitive impairment and dementia (PSCID); the interaction between stimulation targets and parameters influences the response to the stimulation. However, the most efficacious treatment for improving different domains of cognitive impairment remains unknown. OBJECTIVE: We aimed to conduct a systematic review and network meta-analysis (NMA) to compare the efficacy of various scalp stimulation protocols used in PSCID treatment. METHODS: Randomized controlled trials of scalp stimulation in patients with PSCID were searched in eight databases over the past 20 years. Standardized mean differences (SMDs) for global and subdomain cognitive scores were pooled in Bayesian NMA. Moderators were examined using meta-regression analysis. RESULTS: A total of 90 trials, with 6199 patients, were included. Low-frequency repetitive transcranial magnetic stimulation (rTMS) over the unaffected dorsolateral prefrontal cortex (DLPFC) was highly suggested for alleviating global severity (SMD = 1.11, 95% CI (0.64, 1.57)). High-frequency rTMS over the left DLPFC was recommended for language use (1.85 (1.18, 2.52)), executive function (0.85 (0.36, 1.33)), orientation deficits (0.59 (0.07, 1.13)), and attention (0.85 (0.27, 1.43)). Anodal transcranial direct current stimulation over the affected DLPFC (2.03 (0.72, 3.34)) was recommended for treating memory impairment. Meta-regression analyses showed significant associations within attention, language and orientation. CONCLUSION: Overall, different cognitive domains have different optimal scalp stimulation prescriptions, and activating the affected key brain regions and inhibiting the unaffected area is still the most effective treatment.
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Disfunção Cognitiva , Demência , Acidente Vascular Cerebral , Estimulação Transcraniana por Corrente Contínua , Humanos , Teorema de Bayes , Metanálise em Rede , Couro Cabeludo , Disfunção Cognitiva/etiologia , Disfunção Cognitiva/terapia , Acidente Vascular Cerebral/complicações , Demência/complicações , Demência/terapiaRESUMO
Pannexin 1 (Panx1) forms ATP-permeable membrane channels that play roles in purinergic signaling in the nervous system. A link between Panx1 activity and neurodegenerative disorders including Parkinson's disease (PD) has been suggested, but experimental evidence is limited. Here, a zebrafish model of PD was produced by exposing panx1a+/+ and panx1a-/- zebrafish larvae to 6-hydroxydopamine (6-OHDA). Electrical stimulation in a microfluidic chip and quantitative real-time-qPCR of zebrafish larvae tested the role of Panx1 in both pathological and normal conditions. After 72-h treatment with 6-OHDA, the electric-induced locomotor activity of 5 days post fertilization (5dpf) panx1a+/+ larvae were reduced, while the stimulus did not affect locomotor activity of age-matched panx1a-/- larvae. A RT-qPCR analysis showed an increase in the expression of genes that are functionally related to dopaminergic signaling, like the tyrosine hydroxylase (th2) and the leucine-rich repeat kinase 2 (lrrk2). Extending the 6-OHDA treatment duration to 120 h caused a significant reduction in the locomotor response of 7dpf panx1a-/- larvae compared to the untreated panx1a-/- group. The RT-qPCR data showed a reduced expression of dopaminergic signaling genes in both genotypes. It was concluded that the absence of Panx1a channels compromised dopaminergic signaling in 6-OHDA-treated zebrafish larvae and that the increase in the expression of dopaminergic genes was transient, most likely due to a compensatory upregulation. We propose that zebrafish Panx1a models offer opportunities to shed light on PD's physiological and molecular basis. Panx1a might play a role on the progression of PD, and therefore deserves further investigation.
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BACKGROUND: Among its pleiotropic properties, gender-affirming hormone therapy (GHT) affects regional brain volumes. The hypothalamus, which regulates neuroendocrine function and associated emotional and cognitive processes, is an intuitive target for probing GHT effects. We sought to assess changes to hypothalamus and hypothalamic subunit volumes after GHT, thereby honouring the region's anatomical and functional heterogeneity. METHODS: Individuals with gender dysphoria and cisgender controls underwent 2 MRI measurements, with a median interval of 145 days (interquartile range [IQR] 128.25-169.75 d, mean 164.94 d) between the first and second MRI. Transgender women (TW) and transgender men (TM) underwent the first MRI before GHT and the second MRI after approximately 4.5 months of GHT, which comprised estrogen and anti-androgen therapy in TW or testosterone therapy in TM. Hypothalamic volumes were segmented using FreeSurfer, and effects of GHT were tested using repeated-measures analysis of covariance. RESULTS: The final sample included 106 participants: 38 TM, 15 TW, 32 cisgender women (CW) and 21 cisgender men (CM). Our analyses revealed group × time interaction effects for total, left and right hypothalamus volume, and for several subunits (left and right inferior tubular, left superior tubular, right anterior inferior, right anterior superior, all p corr < 0.01). In TW, volumes decreased between the first and second MRI in these regions (all p corr ≤ 0.01), and the change from the first to second MRI in TW differed significantly from that in CM and CW in several subunits (p corr < 0.05). LIMITATIONS: We did not address the influence of transition-related psychological and behavioural changes. CONCLUSION: Our results suggest a subunit-specific effect of GHT on hypothalamus volumes in TW. This finding is in accordance with previous reports of positive and negative effects of androgens and estrogens, respectively, on cerebral volumes.
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Emoções , Disforia de Gênero , Masculino , Feminino , Humanos , Disforia de Gênero/diagnóstico por imagem , Disforia de Gênero/tratamento farmacológico , Hipotálamo/diagnóstico por imagem , TestosteronaRESUMO
BACKGROUND: Sex-specific differences in brain connectivity were found in various neuroimaging studies, though little is known about sex steroid effects on insular functioning. Based on well-characterized sex differences in emotion regulation, interoception and higher-level cognition, gender-dysphoric individuals receiving gender-affirming hormone therapy represent an interesting cohort to investigate how sex hormones might influence insular connectivity and related brain functions. METHODS: To analyze the potential effect of sex steroids on insular connectivity at rest, 11 transgender women, 14 transgender men, 20 cisgender women, and 11 cisgender men were recruited. All participants underwent two magnetic resonance imaging sessions involving resting-state acquisitions separated by a median time period of 4.5 months and also completed the Bermond-Vorst alexithymia questionnaire at the initial and final examination. Between scans, transgender subjects received gender-affirming hormone therapy. RESULTS: A seed based functional connectivity analysis revealed a significant 2-way interaction effect of group-by-time between right insula, cingulum, left middle frontal gyrus and left angular gyrus. Post-hoc tests demonstrated an increase in connectivity for transgender women when compared to cisgender men. Furthermore, spectral dynamic causal modelling showed reduced effective connectivity from the posterior cingulum and left angular gyrus to the left middle frontal gyrus as well as from the right insula to the left middle frontal gyrus. Alexithymia changes were found after gender-affirming hormone therapy for transgender women in both fantasizing and identifying. CONCLUSION: These findings suggest a considerable influence of estrogen administration and androgen suppression on brain networks implicated in interoception, own-body perception and higher-level cognition.
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Disforia de Gênero , Transexualidade , Humanos , Masculino , Feminino , Disforia de Gênero/tratamento farmacológico , Identidade de Gênero , Transexualidade/tratamento farmacológico , Encéfalo , Imageamento por Ressonância Magnética/métodos , Hormônios Esteroides Gonadais/farmacologia , EsteroidesRESUMO
Silica glass is a high-performance material used in many applications such as lenses, glassware, and fibers. However, modern additive manufacturing of micro-scale silica glass structures requires sintering of 3D-printed silica-nanoparticle-loaded composites at ~1200 °C, which causes substantial structural shrinkage and limits the choice of substrate materials. Here, 3D printing of solid silica glass with sub-micrometer resolution is demonstrated without the need of a sintering step. This is achieved by locally crosslinking hydrogen silsesquioxane to silica glass using nonlinear absorption of sub-picosecond laser pulses. The as-printed glass is optically transparent but shows a high ratio of 4-membered silicon-oxygen rings and photoluminescence. Optional annealing at 900 °C makes the glass indistinguishable from fused silica. The utility of the approach is demonstrated by 3D printing an optical microtoroid resonator, a luminescence source, and a suspended plate on an optical-fiber tip. This approach enables promising applications in fields such as photonics, medicine, and quantum-optics.
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The interest in 2D materials continues to grow across numerous scientific disciplines as compounds with unique electrical, optical, chemical, and thermal characteristics are being discovered. All these properties are governed by an all-surface nature and nanoscale confinement, which can easily be altered by extrinsic influences, such as defects, dopants or strain, adsorbed molecules, and contaminants. Here, we report on the ubiquitous presence of polymeric adlayers on top of layered transition metal dichalcogenides (TMDs). The atomically thin layers, not evident from common analytic methods, such as Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), or scanning electron microscopy (SEM), could be identified with highly resolved time-of-flight secondary ion mass spectrometry (TOF-SIMS). The layers consist of hydrocarbons, which preferentially adsorb to the hydrophobic van der Waals surfaces of TMDs, derived from the most common methods. Fingerprint fragmentation patterns enable us to identify certain polymers and link them to those used during preparation and storage of the TMDs. The ubiquitous presence of polymeric films on 2D materials has wide reaching implications for their investigation, processing, and applications. In this regard, we reveal the nature of polymeric residues after commonly used transfer procedures on MoS2 films and investigate several annealing procedures for their removal.
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Understanding and treating Alzheimer's disease (AD) has been a remarkable challenge for both scientists and physicians. Although the amyloid-beta and tau protein hypothesis have largely explained the key pathological features of the disease, the mechanisms by which such proteins accumulate and lead to disease progression are still unknown. Such lack of understanding disrupts the development of disease-modifying interventions, leaving a therapeutic gap that remains unsolved. Nonetheless, the recent discoveries of the glymphatic pathway and the meningeal lymphatic system as key components driving central solute clearance revealed another mechanism underlying AD pathogenesis. In this regard, this narrative review integrates the glymphatic and meningeal lymphatic systems as essential components involved in AD pathogenesis. Moreover, it discusses the emerging evidence suggesting that nutritional supplementation, non-invasive brain stimulation, and traditional Chinese medicine can improve the pathophysiology of the disease by increasing glymphatic and/or meningeal lymphatic function. Given that physical exercise is a well-regarded preventive and pro-cognitive intervention for dementia, we summarize the evidence suggesting the glymphatic system as a mediating mechanism of the physical exercise therapeutic effects in AD. Targeting these central solute clearance systems holds the promise of more effective treatment strategies.
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Doença de Alzheimer , Sistema Glinfático , Humanos , Doença de Alzheimer/metabolismo , Encéfalo/metabolismo , Sistema Linfático/metabolismo , Sistema Linfático/patologia , Sistema Glinfático/metabolismo , Sistema Glinfático/patologia , Peptídeos beta-Amiloides/metabolismoRESUMO
The performance of two-dimensional (2D) materials is promising for electronic, photonic, and sensing devices since they possess large surface-to-volume ratios, high mechanical strength, and broadband light sensitivity. While significant advances have been made in synthesizing and transferring 2D materials onto different substrates, there is still the need for scalable patterning of 2D materials with nanoscale precision. Conventional lithography methods require protective layers such as resist or metals that can contaminate or degrade the 2D materials and deteriorate the final device performance. Current resist-free patterning methods are limited in throughput and typically require custom-made equipment. To address these limitations, we demonstrate the noncontact and resist-free patterning of platinum diselenide (PtSe2), molybdenum disulfide (MoS2), and graphene layers with nanoscale precision at high processing speed while preserving the integrity of the surrounding material. We use a commercial, off-the-shelf two-photon 3D printer to directly write patterns in the 2D materials with features down to 100 nm at a maximum writing speed of 50 mm/s. We successfully remove a continuous film of 2D material from a 200 µm × 200 µm substrate area in less than 3 s. Since two-photon 3D printers are becoming increasingly available in research laboratories and industrial facilities, we expect this method to enable fast prototyping of devices based on 2D materials across various research areas.