Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 38
Filtrar
1.
ACS Omega ; 9(3): 3923-3930, 2024 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-38284021

RESUMO

Decoration of vanadium nitride nanoparticles on carbon nanotubes creates electrodes with three different energy storage mechanisms that operate synergistically to give a high specific capacitance with a low active mass. Calculation and measurements further indicate the power and energy density to be as high as 105-106 W/kg and 102 Wh/kg, respectively. Particle attachment also greatly improves the capacitive coefficient, including ionic transmittance, charge transfer, porosity, and conductivity. Corrosion tests based on the Tafel method reveal the corrosion potential and current of electrodes as low as -0.721 V and 7.53 × 10-4 A, respectively.

2.
RSC Adv ; 13(47): 33062-33066, 2023 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-37954420

RESUMO

Conductive papers made from carbon nanotubes and wood fibers exhibit a p-type character. N2 plasma treatment converts paper into n-type and conversion is verified by elemental analyses, work function and Hall-effect measurements. By screening one face of p-type paper in plasma, the p-n junctions are successfully created along the thickness direction and electrical rectification is evident by current-voltage measurement.

3.
Angew Chem Int Ed Engl ; 62(44): e202311550, 2023 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-37666796

RESUMO

Single-atom catalysts exhibit superior CO2 -to-CO catalytic activity, but poor kinetics of proton-coupled electron transfer (PCET) steps still limit the overall performance toward the industrial scale. Here, we constructed a Fe-P atom paired catalyst onto nitrogen doped graphitic layer (Fe1 /PNG) to accelerate PCET step. Fe1 /PNG delivers an industrial CO current of 1 A with FECO over 90 % at 2.5 V in a membrane-electrode assembly, overperforming the CO current of Fe1 /NG by more than 300 %. We also decrypted the synergistic effects of the P atom in the Fe-P atom pair using operando techniques and density functional theory, revealing that the P atom provides additional adsorption sites for accelerating water dissociation, boosting the hydrogenation of CO2 , and enhancing the activity of CO2 reduction. This atom-pair catalytic strategy can modulate multiple reactants and intermediates to break through the inherent limitations of single-atom catalysts.

4.
ACS Nano ; 17(18): 18616-18628, 2023 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-37713681

RESUMO

P2-type layered transition-metal (TM) oxides, NaxTMO2, are highly promising as cathode materials for sodium-ion batteries (SIBs) due to their excellent rate capability and affordability. However, P2-type NaxTMO2 is afflicted by issues such as Na+/vacancy ordering and multiple phase transitions during Na-extraction/insertion, leading to staircase-like voltage profiles. In this study, we employ a combination of high Na content and Li dual-site substitution strategies to enhance the structural stability of a P2-type layered oxide (Na0.80Li0.024[Li0.065Ni0.22Mn0.66]O2). The experimental results reveal that these approaches facilitate the oxidation of Mn ions to a higher valence state, thereby affecting the local environment of both TM and Na ions. The resulting modification in the local structure significantly improves the Na-ion storage capabilities as required for cathode materials in SIBs. Furthermore, it induces a solid-solution reaction and enables nearly zero-strain operation (ΔV = 0.7%) in the Na0.80Li0.024[Li0.065Ni0.22Mn0.66]O2 cathode during cycling. The assembled full cells demonstrate an exceptional rate performance, with a retention rate of 87% at 10 C compared to that of 0.1 C, as well as an ultrastable cycling capability, maintaining a capacity retention of 73% at 2 C after 1000 cycles. These findings offer valuable insights into the electronic and structural chemistry of ultrastable cathode materials with "zero-strain" Na-ion storage.

5.
J Colloid Interface Sci ; 651: 18-26, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37536256

RESUMO

Single-atom catalysts supported on semiconductors can serve as active sites for efficient oxygen reduction to hydrogen peroxide (H2O2). However, researchers have long been puzzled by the lack of guidance on optimizing the performance of single-atom photocatalysts. In this study, we propose a versatile strategy that utilizes carbon vacancies to regulate the electronic configuration of antimony (Sb) atoms on carbon nitrides (C3N4). This strategy has been found to significantly enhance the photocatalytic production of H2O2. The H2O2 evolution rate of Sb single-atom on carbon vacancy-rich C3N4 (designated as Sb1/Cv-C3N4) is 5.369 mmol g-1h-1, which is 10.9 times higher than C3N4 alone. By combining experimental characterizations and density functional theory simulations, we reveal the strong electronic interaction between Sb atoms and carbon vacancy-rich C3N4. This interaction is capable for maintaining the electron-rich state of Sb atoms, facilitating efficient electron transfer to pauling-type absorbed oxygen, and ultimately enhancing the formation of *OOH intermediates. This innovative defect-engineering approach can manipulate the electronic configuration of single-atom catalysts, providing a new avenue to boost the photocatalytic oxygen reduction reaction towards H2O2 production.

6.
ACS Nano ; 17(13): 12884-12894, 2023 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-37339159

RESUMO

Surface and interface engineering, especially the creation of abundant Cu0/Cu+ interfaces and nanograin boundaries, is known to facilitate C2+ production during electrochemical CO2 reductions over copper-based catalysts. However, precisely controlling the favorable nanograin boundaries with surface structures (e.g., Cu(100) facets and Cu[n(100)×(110)] step sites) and simultaneously stabilizing Cu0/Cu+ interfaces is challenging, since Cu+ species are highly susceptible to be reduced into bulk metallic Cu at high current densities. Thus, an in-depth understanding of the structure evolution of the Cu-based catalysts under realistic CO2RR conditions is imperative, including the formation and stabilization of nanograin boundaries and Cu0/Cu+ interfaces. Herein we demonstrate that the well-controlled thermal reduction of Cu2O nanocubes under a CO atmosphere yields a remarkably stable Cu2O-Cu nanocube hybrid catalyst (Cu2O(CO)) possessing a high density of Cu0/Cu+ interfaces, abundant nanograin boundaries with Cu(100) facets, and Cu[n(100)×(110)] step sites. The Cu2O(CO) electrocatalyst delivered a high C2+ Faradaic efficiency of 77.4% (56.6% for ethylene) during the CO2RR under an industrial current density of 500 mA/cm2. Spectroscopic characterizations and morphological evolution studies, together with in situ time-resolved attenuated total reflection-surface enhanced infrared absorption spectroscopy (ATR-SEIRAS) studies, established that the morphology and Cu0/Cu+ interfacial sites in the as-prepared Cu2O(CO) catalyst were preserved under high polarization and high current densities due to the nanograin-boundary-abundant structure. Furthermore, the abundant Cu0/Cu+ interfacial sites on the Cu2O(CO) catalyst acted to increase the *CO adsorption density, thereby increasing the opportunity for C-C coupling reactions, leading to a high C2+ selectivity.

7.
J Psychiatr Res ; 161: 377-385, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37012197

RESUMO

Major depressive disorder places a great burden on healthcare resources worldwide. Antidepressants are the first-line treatment for major depressive disorder, but if patients don't respond adequately, brain stimulation therapy may be needed as second-line treatment. Digital phenotyping in patients with major depressive disorder will aid in the timely prediction of treatment effectiveness. This study explored electroencephalographic (EEG) signatures that diversify depression treatment responsivity, including antidepressant administration or brain stimulation therapy. Resting-state, pre-treatment EEG sequences from depressive patients who received fluoxetine treatment (n = 55; 26 remitters and 29 poor responders) or electroconvulsive therapy (ECT, n = 58; 36 remitters and 22 nonremitters) were recorded on 19 channels. Twenty-nine EEG segments were obtained from each patient per recording electrode. Power spectral analysis was conducted for feature extraction and showed the highest predictive accuracy for fluoxetine or ECT outcomes. Both occurred with beta-band oscillations within right-side frontal-central (F1-score = 0.9437) or prefrontal areas of the brain (F1-score = 0.9416), respectively. Significantly higher beta-band power was observed among patients who lacked adequate treatment response than the remitters, specifically at 19.2 Hz or 24.5 Hz for fluoxetine administration or ECT outcome, respectively. Our findings indicated that pre-treatment, right-side cortical hyperactivation is associated with poor outcomes of antidepressant-based or ECT-based treatment in major depression. Whether depression treatment response rates can be improved by reducing the high-frequency EEG power in corresponding areas of the brain to provide a protective effect against depression recurrence warrants further study.


Assuntos
Transtorno Depressivo Maior , Eletroconvulsoterapia , Humanos , Transtorno Depressivo Maior/tratamento farmacológico , Fluoxetina/uso terapêutico , Antidepressivos/uso terapêutico , Lobo Frontal , Resultado do Tratamento
8.
J Chin Med Assoc ; 86(7): 688-695, 2023 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-36872476

RESUMO

BACKGROUND: Both inflammation and oxidative stress contribute to the pathogenesis of sepsis and its associated organ damage. Angiotensin-(1-7), acting through the Mas receptor and angiotensin II-type 2 receptors (AT2R), could attenuate organ dysfunction and improve survival in rats with sepsis. However, the role of AT2R in inflammation and oxidative stress in rats with sepsis is unclear. Therefore, this study examined the modulatory effects and molecular mechanism of AT2R stimulation in rats with polymicrobial sepsis. METHODS: Male Wistar rats underwent cecal ligation and puncture (CLP) or sham surgery followed by the administration of saline or CGP42112 (a selective, high-affinity agonist of AT2R, 50 µg/kg intravenously) at 3 hours after sham surgery or CLP. The changes in hemodynamics, biochemical variables, and plasma levels of chemokines and nitric oxide were detected during the 24-hour observation. Organ injury was evaluated by histological examination. RESULTS: We found that CLP evoked delayed hypotension, hypoglycemia, and multiple organ injuries, characterized by elevated plasma biochemical parameters and histopathological changes. These effects were attenuated by treatment with CGP42112. CGP42112 significantly attenuated plasma chemokines and nitric oxide production and reduced liver inducible nitric oxide synthase and nuclear factor kappa-B expression. More importantly, CGP42112 significantly improved the survival of rats with sepsis (50% vs. 20% at 24 h after CLP, p < 0.05). CONCLUSION: The protective effects of CGP42112 may be related to anti-inflammatory responses, suggesting that the stimulation of AT2R is a promising therapeutic candidate for the treatment of sepsis.


Assuntos
Óxido Nítrico , Sepse , Ratos , Masculino , Animais , Ratos Wistar , Receptor Tipo 2 de Angiotensina/uso terapêutico , Sepse/complicações , Sepse/tratamento farmacológico , Inflamação
9.
J Am Chem Soc ; 145(13): 7242-7251, 2023 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-36877826

RESUMO

Sn-based materials have been demonstrated as promising catalysts for the selective electrochemical CO2 reduction reaction (CO2RR). However, the detailed structures of catalytic intermediates and the key surface species remain to be identified. In this work, a series of single-Sn-atom catalysts with well-defined structures is developed as model systems to explore their electrochemical reactivity toward CO2RR. The selectivity and activity of CO2 reduction to formic acid on Sn-single-atom sites are shown to be correlated with Sn(IV)-N4 moieties axially coordinated with oxygen (O-Sn-N4), reaching an optimal HCOOH Faradaic efficiency of 89.4% with a partial current density (jHCOOH) of 74.8 mA·cm-2 at -1.0 V vs reversible hydrogen electrode (RHE). Employing a combination of operando X-ray absorption spectroscopy, attenuated total reflectance surface-enhanced infrared absorption spectroscopy, Raman spectroscopy, and 119Sn Mössbauer spectroscopy, surface-bound bidentate tin carbonate species are captured during CO2RR. Moreover, the electronic and coordination structures of the single-Sn-atom species under reaction conditions are determined. Density functional theory (DFT) calculations further support the preferred formation of Sn-O-CO2 species over the O-Sn-N4 sites, which effectively modulates the adsorption configuration of the reactive intermediates and lowers the energy barrier for the hydrogenation of *OCHO species, as compared to the preferred formation of *COOH species over the Sn-N4 sites, thereby greatly facilitating CO2-to-HCOOH conversion.

10.
J Surg Res ; 279: 526-532, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35868036

RESUMO

INTRODUCTION: Sepsis and related complications lead to high morbidity and mortality in humans and animals. Olmesartan medoxomil (OLM), a nonpeptide angiotensin II type 1 receptor blocker, has antiinflammatory and antioxidative effects in various experimental animal models. The present study aimed to investigate whether OLM protects against sepsis in a clinically relevant model of polymicrobial sepsis induced by cecal ligation and puncture (CLP). METHODS: Sepsis was induced by CLP in anesthetized rats. OLM was administered intraperitoneally 3 h after CLP onset. Hemodynamic, biochemical, and inflammatory parameters were analyzed. RESULTS: The administration of OLM in CLP rats significantly improved their survival rate. Moreover, OLM mitigated CLP-induced hypotension and organ injury (indicated by biochemical parameters), but not tachycardia. OLM significantly reduced the plasma levels of interleukin-6 and nitric oxide. CONCLUSIONS: OLM markedly attenuated CLP-induced hypotension and organ injury, and hence improved survival by inhibiting the inflammatory response and nitrosative stress in this clinically relevant model of sepsis.


Assuntos
Peritonite , Sepse , Bloqueadores do Receptor Tipo 1 de Angiotensina II , Animais , Ceco , Modelos Animais de Doenças , Humanos , Imidazóis , Interleucina-6 , Óxido Nítrico , Olmesartana Medoxomila , Peritonite/complicações , Peritonite/etiologia , Ratos , Ratos Wistar , Sepse/complicações , Sepse/tratamento farmacológico , Tetrazóis
11.
Sci Rep ; 12(1): 11203, 2022 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-35778596

RESUMO

Suspension made of Fe2(SO4)3(aq), polyvinyl alcohol and carbon nanotubes is placed in electric field to separate charges. Charges remain separated as suspension solidifies, forming composite films with cations and anions enriched at opposite sides. Polarized films behave as junction diodes with forward current and threshold voltage found to be 10-4-10-5 A and 2.4-2.6 V at ± 5 V. Rectification is preserved in strained composite films.

12.
Psychosom Med ; 84(5): 621-631, 2022 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-35420584

RESUMO

OBJECTIVE: Autonomic neural controls in sleep regulation have been previously demonstrated; however, whether these alternations can be observed by different sleep staging approaches remains unclear. Two established methods for sleep staging-the standardized visual scoring and the cardiopulmonary coupling (CPC) analysis based on electrocardiogram-were used to explore the cardiovascular profiles of sleep. METHODS: Overnight polysomnography was recorded together with continuous beat-to-beat blood pressure. Cortical activity, heart rate variability, blood pressure variability, and baroreflex sensitivity during sleep stages from 24 nights of sleep were obtained from 15 normotensive participants and analyzed. RESULTS: Non-rapid eye movement sleep (NREM) from visual scoring and restful sleep (RS) of CPC both showed the highest delta power of electroencephalogram (EEG) and lowest beta activity of EEG in comparison with other sleep stages (p < .001); likewise, the lowest total power of heart rate variability and suppressed vascular-sympathetic activity, reflected by low-frequency power of blood pressure variability, as well as a trend in elevated baroreflex sensitivity, were observed in the NREM or RS. This suppressed vascular-sympathetic activity during stable sleep further exhibited a significant correlation with increased slow-wave activity (NREM: r = -0.292 ± 0.34, p = .002; RS: r = -0.209 ± 0.30, p = .010). CONCLUSIONS: Autonomic nervous system is evidently associated with stable sleep, as indicated by the similar findings obtained from sleep stages categorized by standardized visual scoring or CPC analysis. Such association between cardiovascular neural activity and sleep EEGs can be observed regardless of the sleep staging approach followed.


Assuntos
Barorreflexo , Fases do Sono , Barorreflexo/fisiologia , Eletrocardiografia , Eletroencefalografia , Frequência Cardíaca/fisiologia , Humanos , Sono/fisiologia , Fases do Sono/fisiologia
13.
J Pers Med ; 12(3)2022 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-35330359

RESUMO

Background: Renal cell carcinoma (RCC) is the most common neoplasm in kidneys, and surgical resection remains the mainstay treatment. Few studies have investigated how the postoperative pain changes over time and what has affected its trajectory. This study aimed to characterize the variations in postoperative pain over time and investigate associated factors after RCC surgery. Methods: This retrospective study was conducted in a single medical center in Taiwan, where maximal pain scores in a numeric rating scale were recorded daily in the first five postoperative days (PODs) after RCC surgery. Latent curve models were developed, using two latent variables, intercept and slope, which represented the baseline pain and rate of pain resolution. These models explain the variations in postoperative pain scores over time. A predictive model for postoperative pain trajectories was also constructed. Results: There were 861 patients with 3850 pain observations included in the analysis. Latent curve analysis identified that female patients and those with advanced cancer (stage III and IV) tended to have increased baseline pain scores (p = 0.028 and 0.012, respectively). Furthermore, patients over 60 years, without PCA use (both p < 0.001), and with more surgical blood loss (p = 0.001) tended to have slower pain resolution. The final predictive model fit the collected data acceptably (RMSEA = 0.06, CFI = 0.95). Conclusion: Latent curve analysis identified influential factors of acute pain trajectories after RCC surgery. This study may also help elucidate the complex relationships between the variations in pain intensity over time and their determinants, and guide personalized pain management after surgery for RCC.

14.
J Pers Med ; 12(3)2022 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-35330480

RESUMO

Various forms of cognitive behavioral therapy for insomnia (CBT-i) have been developed to improve its scalability and accessibility for insomnia management in young people, but the efficacy of digitally-delivered cognitive behavioral therapy for insomnia (dCBT-i) remains uncertain. This study systematically reviewed and evaluated the effectiveness of dCBT-i among young individuals with insomnia. We conducted comprehensive searches using four electronic databases (PubMed, Cochrane Library, PsycINFO, and Embase; until October 2021) and examined eligible records. The search strategy comprised the following three main concepts: (1) participants were adolescents or active college students; (2) dCBT-I was employed; (3) standardized tools were used for outcome measurement. Four randomized controlled trials qualified for meta-analysis. A significant improvement in self-reported sleep quality with a medium-to-large effect size after treatment (Hedges's g = -0.58~-0.80) was noted. However, a limited effect was detected regarding objective sleep quality improvement (total sleep time and sleep efficiency measured using actigraphy). These preliminary findings from the meta-analysis suggest that dCBT-i is a moderately effective treatment in managing insomnia in younger age groups, and CBT-i delivered through the web or a mobile application is an acceptable approach for promoting sleep health in young people.

15.
Sci Rep ; 11(1): 610, 2021 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-33436885

RESUMO

Sepsis can lead to shock, multiple organ failure, and even death. Platelets play an active role in the pathogenesis of sepsis-induced multiple organ failure. Angiotensin (Ang)-(1-7), a biologically active peptide, counteracts various effects of Ang II and attenuates inflammatory responses, reactive oxygen species production, and apoptosis. We evaluated the effects of Ang-(1-7) on organ injury and platelet dysfunction in rats with endotoxaemia. We treated male Wistar rats with saline or lipopolysaccharide (LPS, 10 mg, intravenously) then Ang-(1-7) (1 mg/kg, intravenous infusion for 3 h beginning 30 min after LPS administration). We analysed several haemodynamic, biochemical, and inflammatory parameters, as well as platelet counts and aggregation. Ang-(1-7) improved hypotension and organ dysfunction, and attenuated plasma interleukin-6, chemokines and nitric oxide production in rats after LPS administration. The LPS-induced reduction in platelet aggregation, but not the decreased platelet count, was restored after Ang-(1-7) treatment. The protein expression of iNOS and IκB, but not phosphorylated ERK1/2 and p38, was diminished in Ang-(1-7)-treated LPS rats. The histological changes in liver and lung were significantly attenuated in Ang-(1-7)-treated LPS rats. Our results suggest that Ang-(1-7) ameliorates endotoxaemic-induced organ injury and platelet dysfunction, likely through the inhibition of the inflammatory response and nitric oxide production.


Assuntos
Angiotensina I/farmacologia , Plaquetas/efeitos dos fármacos , Endotoxemia/complicações , Hipotensão/prevenção & controle , Interleucina-6/metabolismo , Lipopolissacarídeos/toxicidade , Insuficiência de Múltiplos Órgãos/prevenção & controle , Fragmentos de Peptídeos/farmacologia , Animais , Plaquetas/patologia , Endotoxemia/induzido quimicamente , Hipotensão/etiologia , Hipotensão/patologia , Masculino , Insuficiência de Múltiplos Órgãos/etiologia , Ratos , Ratos Wistar , Sepse/induzido quimicamente , Sepse/complicações , Vasodilatadores/farmacologia
16.
RSC Adv ; 11(54): 34117-34124, 2021 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-35497274

RESUMO

Nitrogen-doped carbon quantum dots (N-CQDs) exhibit a high quantum yield with controllable emission wavelength and intensity in the blue-green regime. N-CQDs were tested and determined to be thermally and optically stable during 150 °C heat treatment and prolonged UV irradiation. Potential applications of N-CQDs were demonstrated, including excellent Fe3+ sensing in aqueous solution, fluorescent polymer fibres, and stealth quick response coding at visible wavelengths.

17.
J Affect Disord ; 281: 872-879, 2021 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-33220949

RESUMO

BACKGROUND: Intense increased alpha activity in the anterior brain has been recognized as one of the biomarkers of depression. This study aimed to explore whether complexity measures of electroencephalogram (EEG) signals vary across the frontal region between patients with or without remission in depression. METHODS: Ninety-four patients with moderate-to-severe major depression underwent the experiment. Hilbert-Huang transform was applied to extract individual alpha EEG instantaneous amplitude. Averaged regional complexity (SampEnMean) on frontal and frontal-central areas as well as bilateral frontal areas were assessed according to multiscale entropy between the remitters (n = 26/94, 27.66%) and poor responders (n = 29/94, 30.85%). Standard deviation of regional complexity (SampEnSD) was used as a parameter to test the homogeneity of frontal alpha complexity. RESULTS: No significant differences in SampEnMean for the frontal or frontal-central area were observed between the remitters and poor responders. However, the SampEnSD (i.e., regional homogeneity of frontal alpha complexity) significantly increased in the frontal-central area after treatment among the poor responders in comparison to their baseline, whereas the remitters showed an opposite trend. The remitters further showed significantly larger SampEnSD on the left frontal area at baseline, and this lateralization disappeared after antidepressant treatment except for the poor responders. LIMITATIONS: This study was limited by a small sample size and without healthy controls. CONCLUSIONS: Homogeneity in frontal-central alpha complexity and interhemispheric asymmetry normalization of anterior EEG complexity are associated with antidepressant efficacy, suggesting that homogeneity of dynamical brain activity is a key linked to the successful treatment of major depression.


Assuntos
Depressão , Transtorno Depressivo Maior , Antidepressivos/uso terapêutico , Encéfalo , Transtorno Depressivo Maior/tratamento farmacológico , Eletroencefalografia , Humanos
18.
Psychiatry Res ; 295: 113518, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33189366

RESUMO

Insomnia is a risk factor for hypertension and cardiovascular events, and this association is strongest for sleep-onset insomnia. This study explored morning cardiovascular function in individuals with sleep-onset insomnia by analysing heart rate variability (HRV), blood pressure variability, and baroreflex sensitivity. Sleep quality of fifteen good sleepers and 13 individuals with sleep-onset insomnia was measured by overnight polysomnography, followed by continuous recordings of the participant's blood pressure and heart rate for 10 min immediately after they had woken up the following morning. After morning awakening (averaged time: 12.33 ± 10.48 min), a significantly reduced vagal tone assessed by HRV, including lower total power of HRV, lower high frequency of HRV, and elevated slopes of systolic as well as diastolic blood pressure in the morning with a blunted baroreflex sensitivity in the insomnia group were noted, compared to the control group. No differences in sympathetic-related activity were observed. The regulation of cardiovascular activity by the parasympathetic nervous system plays an important role in sleep-onset insomnia. Weak vagal modulation and blunted baroreflex sensitivity were evident in this insomnia subtype, which indicates that difficulty in initiating sleep can independently affect morning cardiovascular function.


Assuntos
Barorreflexo , Frequência Cardíaca/fisiologia , Distúrbios do Início e da Manutenção do Sono/fisiopatologia , Sono/fisiologia , Adulto , Pressão Sanguínea , Feminino , Humanos , Hipertensão , Masculino , Sistema Nervoso Parassimpático/fisiopatologia , Polissonografia , Fatores de Risco , Nervo Vago
19.
J Psychosom Res ; 126: 109809, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31622837

RESUMO

OBJECTIVE: Increased cardiovascular risk associated with sleep-onset insomnia has been reported, but the patterns of heart rate (HR) transitions during sleep onset in individuals with sleep-onset insomnia remain uncertain. This study explored the HR dynamics during objective and subjective sleep onset transitions among sleep-onset insomnia. METHODS: Seventeen good sleepers and 17 individuals with sleep-onset insomnia had their night-time HR measured. HR and heart rate variability (HRV) were analyzed within 8-min periods of pre- and post-transition of stage N1, stage N2 and subjective sleep onset. RESULTS: A significantly higher low-frequency percentage of HRV was observed in pre-N1 period among insomnia group, compared with good sleepers. Decline in HR begins in 160 s prior to N1 onset among good sleepers, whereas the HRs of insomnia group were reduced only after N1 onset in comparison to their HRs at the time of N1 onset. The good sleepers and insomnia group both had their HRs dropped to a level comparable to their HRs at respective stage N2 onset at 220 s and 80 s prior to N2 onset. No differences in HR was found during subjective sleep onset transition in both groups. CONCLUSION: During the wake-to-sleep transition, a low and stable HR was observed before cortical alternations in good sleepers; however, a consistently high HR until N1 onset was shown among sleep-onset insomnia. This finding suggests a state-dependent and failure to de-arouse from the high arousal level of wakefulness into light sleep is associated with sleep initiation difficulty.


Assuntos
Nível de Alerta/fisiologia , Frequência Cardíaca/fisiologia , Distúrbios do Início e da Manutenção do Sono/fisiopatologia , Sono/fisiologia , Vigília/fisiologia , Adulto , Feminino , Humanos , Masculino , Polissonografia , Adulto Jovem
20.
Crit Care ; 22(1): 269, 2018 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-30367644

RESUMO

BACKGROUND: Sepsis and related multiple organ dysfunction result in high morbidity and mortality. Angiotensin (Ang)-(1-7), a biologically active peptide, has various opposing effects of Ang II. Because the effect of Ang-(1-7) on sepsis is unknown, in this study we aimed to determine the impact of Ang-(1-7) on pathophysiologic changes in a clinically relevant model of polymicrobial sepsis induced by cecal ligation and puncture (CLP). METHODS: Sepsis was induced by CLP in rats under anesthesia. Rats were randomized to one of the following five groups: (1) sham-operated group, (2) Ang-(1-7) (1 mg/kg intravenously infused for 1 h) at 3 h and 6 h after sham operation, (3) CLP, (4) Ang-(1-7) at 3 h after CLP, and (5) Ang-(1-7) at 3 h and 6 h after CLP. Rats were observed for 24 h after CLP surgery and then killed for subsequent histological examination. RESULTS: Ang-(1-7) significantly improved the survival of septic rats (83.3% vs. 36.4% at 24 h following CLP; p = 0.009). Ang-(1-7) attenuated the CLP-induced decreased arterial pressure and organ dysfunction, indicated by diminished biochemical variables and fewer histological changes. Ang-(1-7) significantly reduced the level of plasma interleukin-6 and pulmonary superoxide production (p < 0.05). Moreover, caspase-3 and cytoplasmic IκB expression in liver was significantly lower in the Ang-(1-7)-treated CLP rats (p < 0.05). CONCLUSIONS: In this clinically relevant model of sepsis, Ang-(1-7) ameliorates CLP-induced organ dysfunction and improves survival, possibly through suppressing the inflammatory response, oxidative stress, and apoptosis, suggesting that Ang-(1-7) could be a potential novel therapeutic approach to treatment of peritonitis and polymicrobial sepsis.


Assuntos
Angiotensina I/farmacologia , Fragmentos de Peptídeos/farmacologia , Sepse/mortalidade , Sobrevivência de Tecidos/fisiologia , Angiotensina I/uso terapêutico , Animais , Apoptose/fisiologia , Biomarcadores/análise , Biomarcadores/sangue , Coinfecção/mortalidade , Modelos Animais de Doenças , Interleucina-6/análise , Interleucina-6/sangue , Escores de Disfunção Orgânica , Estresse Oxidativo , Fragmentos de Peptídeos/uso terapêutico , Ratos , Ratos Wistar , Estatísticas não Paramétricas , Superóxidos/análise , Superóxidos/sangue
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...