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1.
J Med Chem ; 67(17): 15816-15836, 2024 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-39163619

RESUMO

CCNE1 amplification occurs in breast cancer and currently lacks effective therapies. PKMYT1 as a synthetic lethal target for CCNE1 amplification holds promise for the treatment of CCNE1-amplified breast cancer. Herein, we discover a series of 2-amino-[1,1'-biphenyl]-3-carboxamide derivatives as potent and selective PKMYT1 inhibitors using structure-based drug design. The representative compound 8ma exhibited excellent potency against PKMYT1, while sparing WEE1. It also suppressed proliferation of the CCNE1-amplified HCC1569 breast cancer cell line and showed synergistic cytotoxicity in combination with gemcitabine. PKMYT1 X-ray cocrystallography confirmed that introduction of key binding interactions between the inhibitors and residues Asp251 and Tyr121 of PKMYT1 greatly enhanced the potency and selectivity of the compounds.


Assuntos
Antineoplásicos , Neoplasias da Mama , Proliferação de Células , Ciclina E , Desenho de Fármacos , Humanos , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Feminino , Relação Estrutura-Atividade , Antineoplásicos/farmacologia , Antineoplásicos/química , Antineoplásicos/síntese química , Antineoplásicos/uso terapêutico , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Ciclina E/metabolismo , Proteínas Oncogênicas/antagonistas & inibidores , Proteínas Oncogênicas/metabolismo , Proteínas Oncogênicas/genética , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Tirosina Quinases/antagonistas & inibidores , Proteínas Tirosina Quinases/metabolismo , Ensaios de Seleção de Medicamentos Antitumorais , Cristalografia por Raios X , Proteínas de Membrana , Proteínas Serina-Treonina Quinases
2.
BMC Cardiovasc Disord ; 24(1): 385, 2024 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-39054422

RESUMO

BACKGROUND: Fontan-associated liver disease (FALD) is one of the most common complications following Fontan procedure, but the impact of FALD on survival outcomes remains controversial. The aim of this systematic review and meta-analysis was to examine and quantify the influence of liver disease on the survival of Fontan patients. METHODS: The Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines were followed, and relevant human studies published from inception up to 12 August 2022 were searched. Stata (version 17.0) was applied to perform the meta-analysis, using random effects (Mantel-Haenszel) models. The I2 statistic was used to assess the heterogeneity. Subgroup analysis and meta-regression were employed to explore the potential sources of heterogeneity and sensitivity analysis was performed to determine the potential influence of each study on the overall pooled results. RESULTS: A total of 312 records were initially identified and 8 studies involving 2,466 patients were selected for inclusion. Results revealed a significant association between the severity of liver disease following Fontan procedure and mortality, which was confirmed by sensitivity analysis and subgroup analysis assessing post-HT mortality. Meta-regression showed that diagnostic methods for liver disease may be a source of heterogeneity. After removal of the FALD patients identified by international classification of disease codes, heterogeneity was markedly reduced, and the positive association between all-cause mortality and the severity of liver disease became significant. CONCLUSIONS: This meta-analysis showed the severity of liver disease following the Fontan procedure has a significant association with mortality. Lifelong follow-up is necessary and imaging examinations are recommended for routine surveillance of liver disease. Among patients with failing Fontan and advanced liver disease, combined heart-liver transplantation may provide additional survival benefits.


Assuntos
Técnica de Fontan , Cardiopatias Congênitas , Hepatopatias , Humanos , Técnica de Fontan/efeitos adversos , Técnica de Fontan/mortalidade , Hepatopatias/mortalidade , Hepatopatias/diagnóstico , Hepatopatias/cirurgia , Hepatopatias/etiologia , Fatores de Risco , Medição de Risco , Cardiopatias Congênitas/cirurgia , Cardiopatias Congênitas/mortalidade , Cardiopatias Congênitas/diagnóstico , Resultado do Tratamento , Masculino , Feminino , Criança , Adolescente , Adulto , Adulto Jovem , Fatores de Tempo , Pré-Escolar , Índice de Gravidade de Doença
3.
Pediatr Res ; 2024 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-38951655

RESUMO

BACKGROUND: Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease (CCHD) with multifactorial etiology. We aimed to investigate the metabolic profiles of CCHD and their independent contributions to TOF. METHODS: A cohort comprising 42 individuals with TOF and atrial septal defect (ASD) was enrolled. Targeted ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) was employed to systematically analyze metabolite levels and identify TOF-associated metabolic profiles. RESULTS: Of 370 identified metabolites in tissue and 284 in plasma, over one-third of metabolites showed an association with microbiome. Differential metabolic pathways including amino acids biosynthesis, ABC (ATP-binding cassette) transporters, carbon metabolism, and fatty acid biosynthesis, shed light on TOF biological phenotypes. Additionally, ROC curves identified potential biomarkers, such as erythronic acid with an AUC of 0.868 in plasma, and 3-ß-hydroxy-bisnor-5-cholenic acid, isocitric acid, glutaric acid, ortho-Hydroxyphenylacetic acid, picolinic acid with AUC close to 1 in tissue, whereas the discriminative performance of those substances significantly improved when combined with clinical phenotypes. CONCLUSIONS: Distinct metabolic profiles exhibited robust discriminatory capabilities, effectively distinguishing TOF from ASD patients. These metabolites may serve as biomarkers or key molecular players in the intricate metabolic pathways involved in CCHD development. IMPACT: Distinct metabolic profiles exhibited robust discriminatory capabilities, effectively distinguishing Tetralogy of Fallot from atrial septal defect patients. Similar profiling but inconsistent differential pathways between plasma and tissue. More than one-third metabolites in plasma and tissue are associated with the microbiome. The discovery of biomarkers is instrumental in facilitating early detection and diagnosis of Tetralogy of Fallot. Disturbed metabolism offers insights into interpretation of pathogenesis of Tetralogy of Fallot.

4.
J Econ Entomol ; 117(3): 762-771, 2024 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-38625052

RESUMO

In this study, we compared the growth, development, and fecundity of Arma chinensis (Fallou) reared on pupae of the geometrid Ectropis grisescens Warren fed on tea shoots during different seasons of the year. The raw data on life history were analyzed using the age-stage, 2-sex life table. When reared on spring or winter geometrid pupae, the duration of the immature stage of A. chinensis was significantly longer than in those produced during the summer or autumn. The survival rate of immature A. chinensis reared on autumn geometrid pupae was significantly lower compared to other treatments. Reproductive diapause was observed in adult A. chinensis reared on winter geometrid pupae. The adult preoviposition period (APOP), total preoviposition period (TPOP), and total longevity were significantly longer in A. chinensis reared on winter pupae than in the other treatments. The fecundity of A. chinensis reared on spring geometrid pupae was significantly lower than in the other treatments. The higher intrinsic rate of increase of the A. chinensis reared on summer pupae (r = 0.0966 day-1) and autumn pupae (r = 0.0983 day-1) resulted in higher fecundity, shorter immature duration, and shorter TPOP compared to the winter and spring populations. These findings can be utilized to enhance and sustain biological control of E. grisescens in tea plantations.


Assuntos
Mariposas , Pupa , Estações do Ano , Animais , Pupa/crescimento & desenvolvimento , Pupa/fisiologia , Mariposas/crescimento & desenvolvimento , Mariposas/fisiologia , Masculino , Feminino , Camellia sinensis , Heterópteros/fisiologia , Heterópteros/crescimento & desenvolvimento , Fertilidade , Controle Biológico de Vetores , Longevidade , Brotos de Planta/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento , Larva/fisiologia
5.
J Colloid Interface Sci ; 665: 465-476, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38537592

RESUMO

With the ever-increasing challenge of heavy metal pollution, the imperative for developing highly efficient adsorbents has become apparent to remove metal ions from wastewater completely. In this study, we introduce a novel magnetic core-shell adsorbent, Fe3O4@UiO-66-PDA. It features a polydopamine (PDA) modified zirconium-based metal-organic framework (UiO-66) synthesized through a simple solvothermal method. The adsorbent boasts a unique core-shell architecture with a high specific surface area, abundant micropores, and remarkable thermal stability. The adsorption capabilities of six metal ions (Fe3+, Mn2+, Pb2+, Cu2+, Hg2+, and Cd2+) were systematically investigated, guided by the theory of hard and soft acids and bases. Among these, three representative metal ions (Fe3+, Pb2+, and Hg2+) were scrutinized in detail. The activated Fe3O4@UiO-66-PDA exhibited exceptional adsorption capacities for these metal ions, achieving impressive values of 97.99 mg/g, 121.42 mg/g, and 130.72 mg/g, respectively, at pH 5.0. Moreover, the adsorbent demonstrated efficient recovery from aqueous solution using an external magnet, maintaining robust adsorption efficiency (>80%) and stability even after six cycles. To delve deeper into the optimized adsorption of Hg2+, density functional theory (DFT) analysis was employed, revealing an adsorption energy of -2.61 eV for Hg2+. This notable adsorption capacity was primarily attributed to electron interactions and coordination effects. This study offers valuable insights into metal ion adsorption facilitated, by magnetic metal-organic framework (MOF) materials.

6.
Dalton Trans ; 53(10): 4598-4606, 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38349531

RESUMO

From paddle-wheel starting material Na3Ru2(CO3)4·6H2O, a family of edge-sharing bi-octahedral (ESBO) diruthenium(IV,IV) compounds formulated as Ru2O2(CO3)2(H2O)2L2·nH2O [L = piperazine (1) or 2-methylpiperazine (2), n = 4, and L = 2,2-dimethylpiperazine (3), n = 12] and Ru2O2(CO3)2(OH)4{M(H2O)4}2·nH2O [M = Mg (4), n = 4, and Ni (5), n = 2] were prepared and structurally characterized. The Ru28+ dimer is chelated and bridged by two CO32- and two µ-O in a trans manner, and the Ru-Ru distances fall in the range 2.3808(6)-2.4001(4) Å. Compound 2 shows the shortest Ru-Ru distance for all known ESBO Ru2 compounds reported thus far. Increasing -CH3 groups of terminal piperazine ligands coordinated to the Ru(µ-O)2(µ-O3C)2Ru core, and according to Raman spectra experiments combined with theoretical calculations, the intense bands of compounds 1-3 appearing at ∼360 cm-1 can be assigned to the stretching of Ru-Ru bonds.

7.
BMC Cardiovasc Disord ; 23(1): 458, 2023 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-37710173

RESUMO

BACKGROUND: Patients with repaired tetralogy of Fallot (rTOF) experience long-term chronic pulmonary valve regurgitation resulting in right ventricular (RV) dilatation. According to current guidelines, the evaluation of patients with rTOF for RV dilatation should be based on cardiac magnetic resonance (CMR). However, for many asymptomatic patients, routine CMR is not practical. Our study aims to identify screening methods for CMR based on echocardiographic data, with the goal of establishing a more practical and cheap method of screening for severity of RV dilatation in patients with asymptomatic rTOF. METHODS: Thirty two rTOF patients (mean age, 21(10.5) y, 21 males) with moderate to severe pulmonary regurgitation (PR) were prospectively recruited. Each patient received CMR and echocardiogram examination within 1 month prior to operation and collected clinical data, and then received echocardiogram examination at discharge and 3-6 months post-surgery. RESULTS: RV moderate-severe dilatation was defined as right ventricular end-diastolic volume index (RVEDVI) ≥ 160 ml/m2 or right ventricular end-systolic volume index (RVESVI) ≥ 80 ml/m2 in 15 of 32 patients (RVEDVI, 202.15[171.51, 252.56] ml/m2, RVESVI, 111.99 [96.28, 171.74] ml/m2). The other 17 (RVESDI, 130.19 [117.91, 139.35] ml/m2, RVESVI = 67.91 [63.35, 73.11] ml/m2) were defined as right ventricle mild dilatation, i.e., RVEDVI < 160 ml/m2 and RVESVI < 80 ml/m2, and the two parameters were higher than normal values. Compared with the RV mild dilatation group, patients of RV moderate-severe dilatation have worse cardiac function before surgery (right ventricular ejection fraction, 38.92(9.19) % versus 48.31(5.53) %, p < 0.001; Left ventricular ejection fraction, 59.80(10.26) versus 66.41(4.15), p = 0.021). Patients with RV moderate-severe dilatation faced longer operation time and more blood transfusion during operation (operation time, 271.53(08.33) min versus 170.53(72.36) min, p < 0.01; Intraoperative blood transfusion, 200(175) ml versus 100(50) ml, p = 0.001). Postoperative RV moderate-severe dilatation patients have poor short-term prognosis, which was reflected in a longer postoperative hospital stay (6.59 [2.12] days versus 9.80 [5.10] days, p = 0.024) and a higher incidence of hypohepatia (0[0] % versus 4[26.7] %, p = 0.023). Patients with RV dilatation score > 2.35 were diagnosed with RV moderate-severe dilatation (AUC = 0,882; Sensitivity = 94.1%; Specificity = 77.3%). CONCLUSIONS: RV moderate-severe dilatation is associated with worse preoperative cardiac function and short-term prognosis after PVR in rTOF patients with moderate to severe PR. The RV dilatation score is an effective screening method. When RV dilatation score > 2.35, the patient is indicated for further CMR examination and treatment.


Assuntos
Cardiopatias Congênitas , Insuficiência da Valva Pulmonar , Tetralogia de Fallot , Masculino , Humanos , Adulto , Adulto Jovem , Tetralogia de Fallot/complicações , Tetralogia de Fallot/diagnóstico por imagem , Tetralogia de Fallot/cirurgia , Volume Sistólico , Dilatação , Função Ventricular Esquerda , Função Ventricular Direita , Insuficiência da Valva Pulmonar/diagnóstico por imagem , Insuficiência da Valva Pulmonar/etiologia , Insuficiência da Valva Pulmonar/cirurgia
8.
Chemosphere ; 309(Pt 2): 136791, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36220425

RESUMO

A novel magnetic nanoadsorbent (Fe3O4@SiO2@PAA-SO3H) was synthesized by grafting acrylic acid and sulfonic group to Fe3O4@SiO2 using a facile cross-link technology. The adsorbent presented water-stability and biocompatibility in wastewater, which exhibited high-selectivity capture for Pb(II) and Cu(II) of 182.5 mg/g and 250.7 mg/g, respectively, at pH 6.0. Furthermore, the adsorption-desorption processes show that nanoadsorbent still retains high uptake capacity after 6 cycles, revealing structural stability and advanced recycling. Effects from other ions existed weak interference in removal of Pb(II) and Cu(II). Meanwhile, the mechanism was further analyzed from both electrostatic potential (ESP) and average local ionization energy (ALIE) based on the density functional theory (DFT). The results indicate that interaction among nanoadsorbent and heavy metal ions is bridged by oxygen active sites. As the Fe3O4@SiO2@PAA-SO3H adsorbent is a hierarchical, highly water-dispersible and biocompatible adsorbent, it is a potential new treatment option for wastewater.


Assuntos
Metais Pesados , Poluentes Químicos da Água , Purificação da Água , Águas Residuárias/química , Purificação da Água/métodos , Dióxido de Silício , Chumbo , Poluentes Químicos da Água/análise , Metais Pesados/química , Adsorção , Água/química , Íons , Modelos Teóricos , Oxigênio
9.
Cardiol Res Pract ; 2022: 5166302, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35198242

RESUMO

BACKGROUND: Trimethylamine-N-oxide (TMAO) has been shown to be an important player in cardiovascular disease (CVD) by promoting vascular inflammation and endothelial dysfunction. We recently found that exosomes (Exos) released from TMAO-activated hepatocytes (TMAO-Exos) could significantly induce inflammation and endothelial dysfunction. However, understandings of how are the Exos secreted by hepatocytes, where are they distributed in vivo, and what effects will they have on vascular inflammation remain limited. The present study aimed to explore the hub genes involved in the production of TMAO-Exos and their distributions in vivo and effects on inflammation. METHODS: The transcriptome profiles of primary rat hepatocytes stimulated with TMAO were obtained from the GSE135856 dataset in the Gene Expression Omnibus repository, and the hub genes associated with Exos were screened and verified by qPCR. Next, Exos derived from TMAO-treated hepatocytes were isolated using differential centrifugation and given intravenously to mice. After 24 h, the distributions of DiI-labelled Exos were visualized with a fluorescence microscope, and the levels of proinflammatory genes in the aorta were detected by qPCR. RESULTS: Phgdh, Mdh2, Echs1, Rap2a, Gpd1l, and Slc3a2 were identified as hub genes that may be involved in the production of TMAO-Exos. And TMAO-Exos were found to be efficiently taken up by cardiomyocytes, hepatocytes, and endothelial cells in the aorta and gastrocnemius muscle. Furthermore, TMAO-Exos, but not control-Exos, could significantly promote the mRNA expressions of Tnf, Icam1, Sele, and Cox-2 in the aorta. CONCLUSIONS: We provided clues about how TMAO may stimulate hepatocytes to produce Exos and further offered evidence that Exos secreted by TMAO-treated hepatocytes could be widely distributed in vivo and promote vascular inflammation.

10.
Artigo em Inglês | MEDLINE | ID: mdl-34840586

RESUMO

BACKGROUND: Diarrhea-predominant irritable bowel syndrome (IBS-D) is a functional gastrointestinal disorder that severely affects patients' life. Moxibustion is believed to be an effective way to treat IBS-D. However, the therapeutic effects and the underlying mechanisms in symptom management of IBS-D by different moxibustion therapies remain unclear. METHODS: IBS-D model rats were divided into groups and treated with ginger-partitioned moxibustion (GPM), mild moxibustion (MM), and laser moxibustion (LM) at a temperature of 43°C, respectively. The temperature curves of acupoints were recorded during interventions. The therapeutic effects were evaluated on the basis of general condition, stool, and hematoxylin-eosin staining of the colon tissue. Moreover, the expression of transient receptor potential vanilloid 1 (TRPV1) receptors in both acupoint tissue and colon tissue was analyzed by immunohistochemistry. RESULTS: After moxibustion treatment, the symptoms were improved. The expression of TRPV1 was increased in acupoint tissue and decreased in colon tissue. GPM and MM showed a more significant influence on IBS-D rats compared with LM. The temperature profile of GPM and MM was wave-like, while LM had an almost stable temperature curve. CONCLUSION: GPM, MM, and LM could improve the symptoms in IBS-D rats. Moxibustion might activate TRPV1 channels in the acupoint tissue and induce acupoint functions, which in turn inhibit the pathological activation state of the colon's TRPV1, followed by improvements in abdominal pain and diarrheal symptoms. LM with stable temperature might lead to the desensitization of TRPV1 receptors and the tolerance of acupoint. GPM and MM provided dynamic and repetitive thermal stimulations that perhaps induced acupoint sensitization to increase efficacy. Therefore, dynamic and repetitive thermal stimulation is recommended in the application of moxibustion.

11.
Dalton Trans ; 49(21): 7053-7059, 2020 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-32400777

RESUMO

A family of Ru2 dimers, [Ru2(µ-κ2N,N':κ2N',N''-dpp)2(µ-X)(X)2]q+ (X = Cl, Br, q = 0 and X = I, q = 1) is synthesized from a [Ru2(OAc)4Cl] paddlewheel starting material. The neutral products are mixed-valence Ru25+ dimers with a Ru-Ru bond order of 0.5, while the cationic iodide is a Ru26+ dimer with formal bond order of 1.0. The Ru-Ru distance is strikingly independent of the identity of the halide and the oxidation state of ruthenium, most likely a consequence of the small bridging nitrogen which constrains the geometry. The spectroscopic properties (EPR, UV/Vis) of the Br complex are consistent with a large σ-σ* splitting in [Ru2(µ-κ2N,N':κ2N',N''-dpp)2(µ-Br)(Br)2].

12.
Chem Commun (Camb) ; 56(9): 1369-1372, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31909399

RESUMO

Control of magnetic performances of molecular magnets is essential but few efforts have been documented. A green and efficient sonication assisted synthesis of a new heterometallic diruthenium(ii,iii) carbonate, Na[Ni(H2O)4Ru2(CO3)4]·3H2O (1), was carried out by self-assembling in aqueous solution. Compound 1 exhibits spin-glass behavior below ∼5.0 K, and a systematic investigation of the ultrasonic irradiation influence on the powder samples reveals that their coercivity increases from 50 Oe to 743 Oe with the control of ultrasonic power under appropriate conditions.

13.
Prostaglandins Other Lipid Mediat ; 146: 106380, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31698141

RESUMO

BACKGROUND: The deposition of extracellular matrix (ECM) during hepatic fibrosis is an intermediate process in the progression of multiple chronic liver diseases to cirrhosis. Because activated hepatic stellate cells (HSCs) are the main source of ECM, HSCs activation is the central link in the formation of liver fibrosis. It was reported that the analogs of lipoxin A4 (LXA4) had anti-fibrotic effects, but the mechanisms are still not clear. This study was conducted to explore the possible mechanisms involved in the process of LXA4-mediated inhibition of HSCs activation. METHODS: Rat HSC-T6 cells were activated by LPS and treated with LXA4 and/or BOC-2. The levels of ECM were assessed by hydroxyproline (Hyp) kit. The protein levels of α-SMA, Collagen I and III, MMP-2, MMP-9, TGF-ß1, PDGF A and B, NF-κB P65, phosphorylated NF-κB P65 (P-P65) and NF-κB inhibitor α (I-κBα) were measured via western blot. The mRNA levels of MMP-2 and MMP-9 were observed by real-time PCR. The contents of TGF-ß1 and PDGF were assessed by ELISA kits. Nuclear transfer assay kit was used to assess the activation and translation of NF-κB P65. RESULTS: (1) LPS activated HSC-T6 cells and up-regulated α-SMA, but LXA4 decreased LPS-induced α-SMA in HSC-T6 cells. (2) LXA4 inhibited LPS-induced Hyp production, meanwhile down-regulated LPS-induced Collagen I, Collagen III, MMP-2, and MMP-9 in HSC-T6 cells. (3) LXA4 decreased LPS-induced TGF-ß1 and PDGF in HSC-T6 cells. (4) LXA4 repressed LPS-activated NF-κB signaling pathway, causing a reduction of I-κBα degradation, NF-κB phosphorylation, and NF-κB p65 transposition in HSC-T6 cells. (4) BOC-2, the blocker of LXA4 receptor, inhibited all the effects of LXA4. CONCLUSION: LXA4 inhibited HSCs activation through down-regulation TGF-ß1/PDGF, and repression NF-κB signal pathway.


Assuntos
Citocinas/metabolismo , Células Estreladas do Fígado/metabolismo , Lipoxinas/farmacologia , Transdução de Sinais/efeitos dos fármacos , Fator de Transcrição RelA/metabolismo , Linhagem Celular , Humanos , Lipopolissacarídeos/toxicidade , Lipoxinas/metabolismo
14.
Dalton Trans ; 48(23): 8039-8043, 2019 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-31080985

RESUMO

The synthesis of antiferromagnets (AFMs) has attracted extensive attention in the area of magnetic devices, such as spintronics and memory devices. Following our initial work on the employment of the homo-valent diruthenium(iii,iii) paddle wheel species with high spin states (S = 2) as building blocks and active components for the construction of molecule-based magnetic materials, the reaction of mixed-valent diruthenium(ii,iii) phosphates Ru2(H2PO4)2(H1.5PO4)2(H2O)2·2H2O (1) with H2O2, Cu2+ and ACl (A = K, Rb and Cs) in aqueous solution led to the formation of heterometallic copper diruthenium(iii,iii) phosphates A2[Cu(H2O)4Ru2(HPO4)2(PO4)2(H2O)2]·nH2O [A = K (2); A = Rb and n = 2 (3); A = Cs and n = 3 (4)]. The compounds consist of chain structures in which each octahedral environment of Cu(H2O)42+ bonds to two [Ru(HPO4)2(PO4)2]2- units in a trans manner, forming a ferrimagnetic negative chain {Cu(H2O)4Ru2(HPO4)2(PO4)2(H2O)2}n2n-, exhibiting anomalous magnetic properties. Long-range ordering temperatures, Tc, were observed around 10 K, and the control of the chain structured antiferromagnets exhibiting step-like hysteresis loops was successfully achieved through counterion tuning by replacing K with either Rb or Cs.

15.
J Neurosci Methods ; 123(1): 69-87, 2003 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-12581851

RESUMO

About 1% of the people in the world suffer from epilepsy and 30% of epileptics are not helped by medication. Careful analyses of the electroencephalograph (EEG) records can provide valuable insight and improved understanding of the mechanisms causing epileptic disorders. Wavelet transform is particularly effective for representing various aspects of non-stationary signals such as trends, discontinuities, and repeated patterns where other signal processing approaches fail or are not as effective. In this research, discrete Daubechies and harmonic wavelets are investigated for analysis of epileptic EEG records. Wavelet transform is used to analyze and characterize epileptiform discharges in the form of 3-Hz spike and wave complex in patients with absence seizure. Through wavelet decomposition of the EEG records, transient features are accurately captured and localized in both time and frequency context. The capability of this mathematical microscope to analyze different scales of neural rhythms is shown to be a powerful tool for investigating small-scale oscillations of the brain signals. Wavelet analyses of EEGs obtained from a population of patients can potentially suggest the physiological processes undergoing in the brain in epilepsy onset. A better understanding of the dynamics of the human brain through EEG analysis can be obtained through further analysis of such EEG records.


Assuntos
Eletroencefalografia/estatística & dados numéricos , Epilepsia Tipo Ausência/fisiopatologia , Algoritmos , Biologia Computacional/estatística & dados numéricos , Interpretação Estatística de Dados , Epilepsia Tipo Ausência/diagnóstico , Humanos , Modelos Neurológicos , Neurologia/estatística & dados numéricos
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