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1.
IEEE Trans Neural Netw Learn Syst ; 34(11): 9404-9411, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35442891

RESUMO

This article studies the stability problem of generalized neural networks (GNNs) with time-varying delay. The delay has two cases: the first case is that the delay's derivative has only upper bound, the other case has no information of its derivative or itself is not differentiable. For both two cases, we provide novel stability criteria based on novel Lyapunov-Krasovskii functionals (LKFs) and new negative definite conditions (NDCs) of matrix-valued cubic polynomials. In contrast with the existing methods, in this article, the proposed criteria do not need to introduce extra state variables, and the positive-definite constraint on the novel LKF is relaxed. Moreover, based on free-matrix-based inequality (FMBI) and new NDCs, the stability conditions are expressed as linear matrix inequalities (LMIs). Eventually, the merits and efficiency of the proposed criteria are checked through some classical numerical examples.

2.
IEEE Trans Neural Netw Learn Syst ; 34(10): 7491-7499, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35108209

RESUMO

This article deals with the stability of neural networks (NNs) with time-varying delay. First, a generalized reciprocally convex inequality (RCI) is presented, providing a tight bound for reciprocally convex combinations. This inequality includes some existing ones as special case. Second, in order to cater for the use of the generalized RCI, a novel Lyapunov-Krasovskii functional (LKF) is constructed, which includes a generalized delay-product term. Third, based on the generalized RCI and the novel LKF, several stability criteria for the delayed NNs under study are put forward. Finally, two numerical examples are given to illustrate the effectiveness and advantages of the proposed stability criteria.

3.
IEEE Trans Cybern ; 52(12): 13645-13653, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35077384

RESUMO

This article investigates the problem of delay-dependent stability for the one-area load frequency control (LFC) system with electric vehicles (EVs). Two closed-loop models of the LFC system with EVs are proposed, including the model based on the model reconstructed technique and the model with uncertain parameters that considers state of charge. By employing the Lyapunov-Krasovskii functional method, two delay-dependent stability criteria are presented for the systems under study such that a more accurate admissible delay upper bound (ADUB) can be obtained. Case studies are finally carried out to disclose the interrelationship between the ADUB, PI controller gains, and other parameters of the EVs.

4.
IEEE Trans Neural Netw Learn Syst ; 33(1): 406-415, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-33055041

RESUMO

This article deals with the problem of sampled-data-based synchronization of neural networks with and without considering time delay. A novel looped functional is introduced in the construction of Lyapunov functional, which adequately utilizes the state information of e(tk) , e(t) , e(tk+1) , e(tk-τc) , e(t-τc) , and e(tk+1-τc) . Then, by using this functional and employing a generalized free-matrix-based integral inequality (GFMBII), several sufficient conditions are derived to ensure that the slave system is synchronous with the master system. Also, the sampled-data controller can be obtained by using the linear matrix inequality (LMI) technique. Finally, two numerical examples are illustrated to show the validity and advantages of the proposed method.

5.
IEEE Trans Neural Netw Learn Syst ; 32(3): 975-984, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-32275622

RESUMO

This article is concerned with the problem of dissipativity and stability analysis for a class of neural networks (NNs) with time-varying delays. First, a new augmented Lyapunov-Krasovskii functional (LKF), including some delay-product-type terms, is proposed, in which the information on time-varying delay and system states is taken into full consideration. Second, by employing a generalized free-matrix-based inequality and its simplified version to estimate the derivative of the proposed LKF, some improved delay-dependent conditions are derived to ensure that the considered NNs are strictly ( Q , S , R )- γ -dissipative. Furthermore, the obtained results are applied to passivity and stability analysis of delayed NNs. Finally, two numerical examples and a real-world problem in the quadruple tank process are carried out to illustrate the effectiveness of the proposed method.

6.
J Med Case Rep ; 14(1): 90, 2020 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-32624005

RESUMO

BACKGROUND: Antineutrophil cytoplasmic antibodies comprise a family of autoantibodies that are often used as biomarkers for certain forms of small-vessel vasculitis; however, chronic infections tend to induce the production of antineutrophil cytoplasmic antibodies. Infective endocarditis and hepatitis B virus infection have been reported to exhibit antineutrophil cytoplasmic antibody positivity and to mimic antineutrophil cytoplasmic antibody-associated vasculitis, which may lead to misdiagnosis and inappropriate treatment. CASE PRESENTATION: We report a case of a 46-year-old Han Chinese man with untreated chronic hepatitis B virus infection who featured proteinase-3 antineutrophil cytoplasmic antibody positivity while hospitalized with infective endocarditis. Cardiac ultrasound echocardiography disclosed mitral and aortic regurgitation with vegetation. On the 15th hospital day, the patient underwent mitral and aortic valve replacement and was then treated with antibiotics for more than 1 month. On the 57th hospital day, the patient was discharged. His urinary abnormalities and renal function were gradually recovering. Four months after being discharged, his proteinase-3 antineutrophil cytoplasmic antibody levels had returned to the normal range. CONCLUSIONS: The findings in this study update and expand current understanding of antineutrophil cytoplasmic antibody positivity in patients with both infective endocarditis and hepatitis B virus. Treatment (including surgery, antibiotics, corticosteroids and/or cyclophosphamide, antiviral agents, and even plasma exchange) is challenging when several diseases are combined. Renal biopsy is suggested if the patient's condition allows. Antineutrophil cytoplasmic antibody testing should be repeated after therapy, because some cases might require more aggressive treatment.


Assuntos
Endocardite/complicações , Hepatite B Crônica/complicações , Anticorpos Anticitoplasma de Neutrófilos/sangue , Biomarcadores/sangue , Ecocardiografia , Endocardite/sangue , Endocardite/diagnóstico , Hepatite B Crônica/sangue , Hepatite B Crônica/diagnóstico , Humanos , Masculino , Pessoa de Meia-Idade
7.
ISA Trans ; 101: 170-176, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32067751

RESUMO

This study verifies the H∞ filter design for sampled-data systems with quantization and event-triggered schemes. Firstly, an event-triggered mechanism is presented to detect the release of the necessary sampled-data packet, which significantly reduces the limited network resources compared with the conventional time-triggered mechanism. Secondly, by considering the impact of quantization on the sampled-data system and using the time interval analysis approach, a new sampled-data filtering error model is presented. Then, the Lyapunov-Krasovskii functional (LKF) approach is utilized to derive the required conditions to ensure the asymptotical stability and attain the prescribed H∞ performance for the mentioned system by solving a group of linear matrix inequality (LMIs). Consequently, the corresponding event-triggered and H∞ parameters are co-designed. Finally, the efficiency and the advantage of the presented approach are demonstrated via a mass-spring system example.

8.
BMC Nephrol ; 19(1): 70, 2018 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-29554879

RESUMO

BACKGROUND: Pulmonary hypertension (PH) is a rare disease often associated with high mortality and is recently recognized as a common complication secondary to chronic kidney disease (CKD). Epidemiological data for this disorder across the spectrum of CKD is poorly understood. METHODS: We retrospectively analyzed 705 CKD patients with complete clinical records from July 2013 to September 2015. All the patients were estimated by echocardiography and PH was defined as pulmonary artery systolic pressure (PASP) > 35 mmHg. The prevalence of PH in CKD patients was investigated, and their association was evaluated with a logistic regression model. RESULTS: The overall prevalence of PH was 47.38%, in which mild, moderate and severe PH accounted for 22.13, 15.04 and 10.21%, respectively. The prevalence of PH in CKD stage 1-5 was 14.29, 33.33, 38.89, 40.91 and 64.47%. The prevalence of total PH was 57.63% in PD patients and 58.82% in HD patients. Compared with the non-dialysis patients, the prevalence of PH was much higher in patients receiving dialysis. Body mass index (BMI), hemoglobin, triglyceride (TG), proteinuria, parathyroid hormone (PTH) and estimated glomerular filtration rate (eGFR) were independent risk factors of PH in CKD patients. CONCLUSIONS: The prevalence of PH is increased with the deterioration of renal function, however, which has no direct relation to the severity of PH. PH occurs more frequently in dialysis patients. Higher BMI and TG, more sever anemia, proteinuria and secondary hyperparathyroidism, poor renal dysfunction predict predict the more prevalence of PH in CKD patients.


Assuntos
Hipertensão Pulmonar/diagnóstico por imagem , Hipertensão Pulmonar/epidemiologia , Insuficiência Renal Crônica/diagnóstico por imagem , Insuficiência Renal Crônica/epidemiologia , Adulto , Idoso , Anemia/diagnóstico por imagem , Anemia/epidemiologia , Anemia/fisiopatologia , Feminino , Humanos , Hiperparatireoidismo Secundário/diagnóstico por imagem , Hiperparatireoidismo Secundário/epidemiologia , Hiperparatireoidismo Secundário/fisiopatologia , Hipertensão Pulmonar/fisiopatologia , Masculino , Pessoa de Meia-Idade , Proteinúria/diagnóstico por imagem , Proteinúria/epidemiologia , Proteinúria/fisiopatologia , Insuficiência Renal Crônica/fisiopatologia , Estudos Retrospectivos , Fatores de Risco , Adulto Jovem
9.
J Huazhong Univ Sci Technolog Med Sci ; 34(4): 476-481, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25135714

RESUMO

The efficacy and safety of uric-acid-lowering therapy (UALT) on slowing the progression of chronic kidney disease (CKD) accompanied by hyperuricemia were assessed. We searched Cochrane Library, PubMed, EMbase, CNKI, Wanfang and Vip databases up to November 15, 2012 for randomized controlled trials (RCTs) which compared the effect of UALT to control therapy in hyperuricemic patients secondary to CKD, and then performed quality evaluation and meta-analysis on the included studies. Seven RCTs involving 451 cases were included. UALT delayed the increase of serum creatinine (MD=-62.55 µmol/L, 95% CI: -98.10 to -26.99) and blood urea nitrogen (MD= -6.15 mmol/L, 95% CI: -8.17 to -4.13) as well as the decrease of glomerular filtration rate [MD=5.65 mL/(min·1.73 m2), 95% CI: 1.88 to 9.41], decreased systolic blood pressure (SBP) (MD= -6.08 mmHg, 95% CI: -11.67 to -0.49), and reduced the risk of the renal disease progression (RR=0.30, 95% CI: 0.19 to 0.46). However, there was no statistically significant difference in 24-h urinary protein quantity and diastolic blood pressure (P>0.05). We identified that UALT could delay the progression of CKD with secondary hyperuricemia. And this also indirectly proved that hyperuricemia was a risk factor for the CKD progression.


Assuntos
Progressão da Doença , Hiperuricemia/sangue , Hiperuricemia/terapia , Insuficiência Renal Crônica/sangue , Insuficiência Renal Crônica/terapia , Ácido Úrico/sangue , Pressão Sanguínea , Creatinina/sangue , Feminino , Taxa de Filtração Glomerular , Humanos , Hiperuricemia/fisiopatologia , Masculino , PubMed , Insuficiência Renal Crônica/fisiopatologia , Fatores de Risco , Ureia/sangue
10.
ScientificWorldJournal ; 2014: 391282, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25143974

RESUMO

This paper investigates the stability of static recurrent neural networks (SRNNs) with a time-varying delay. Based on the complete delay-decomposing approach and quadratic separation framework, a novel Lyapunov-Krasovskii functional is constructed. By employing a reciprocally convex technique to consider the relationship between the time-varying delay and its varying interval, some improved delay-dependent stability conditions are presented in terms of linear matrix inequalities (LMIs). Finally, a numerical example is provided to show the merits and the effectiveness of the proposed methods.


Assuntos
Algoritmos , Redes Neurais de Computação
11.
ScientificWorldJournal ; 2014: 789398, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24892090

RESUMO

The problem of stabilization of Lurie networked control systems (NCSs) is investigated in this paper. The network-induced delays in NCSs are assumed to be time-varying and bounded. By utilizing a reciprocally convex technique to consider the relationship between the network-induced delay and its varying interval, a new absolute stability condition is derived in terms of linear matrix inequalities (LMIs). Based on the obtained condition, an improved cone complementary linearisation (CCL) iteration algorithm is presented to design a state feedback controller. The effectiveness of the proposed method is verified by a numerical example.


Assuntos
Modelos Teóricos
12.
IEEE Trans Cybern ; 44(6): 785-92, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24839061

RESUMO

The passivity of neural networks with a time-varying delay and norm-bounded parameter uncertainties is investigated in this paper. A complete delay-decomposing approach is employed to construct a Lyapunov-Krasovskii functional. Then, by utilizing a segmentation technique to consider the time-varying delay and its derivative and introducing some free-weighting matrices to express the relationship between the time-varying delay and its varying interval, some improved passivity criteria are derived. Finally, two numerical examples are given to show the effectiveness and the merits of the proposed method.


Assuntos
Algoritmos , Simulação por Computador , Redes Neurais de Computação , Fatores de Tempo
13.
Hum Vaccin Immunother ; 8(12): 1802-7, 2012 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-22922768

RESUMO

UNLABELLED: The utilization of immunosuppressive agents presents patients with autoimmune nephrosis at a high risk of infection. The present trial was to investigate the efficacy and safety of Broncho-Vaxom on preventing infection in immunosuppressive patients with autoimmune nephrosis. METHODS: 40 patients with autoimmune nephrosis were randomly divided into two groups. The control group (20 cases) routinely received corticosteroid and (or) immunosuppressive therapy, while the treatment group (20 cases) received a capsule containing 7 mg Broncho-Vaxom daily for the first 10 d of each month for 3 consecutive months on the basis of conventional corticosteroid and (or) immunosuppressive therapy. The condition of infection and blood lymphocyte were assessed. RESULTS: 4 patients in the treatment group and 5 patients in the control group were lost during the follow-up period. 25% of patients in the treatment group and 40% of patients in the control group suffered infection. There was no difference in the incidence of infection between the two groups (p > 0.05), while Broncho-Vaxom treated patients suffered a shorter infection period and of which fewer patients need to receive antibiotics therapy (p < 0.05). After the treatment with Broncho-Vaxom, the total number of blood T lymphocyte, proportion of CD4 (+) T lymphocyte, CD4 (+) /CD8 (+) reduced less and the serum IgG rose more obviously (p < 0.05), but the blood lymphocyte, B lymphocyte, CD8 (+) T lymphocyte, IgA and IgM have no differences between the two groups (p > 0.05). CONCLUSION: Broncho-Vaxom might be a good choice for preventing the respiratory infection in nephrosis, especially in the patients under the therapy of immunosuppressive agents.


Assuntos
Doenças Autoimunes/complicações , Infecções Bacterianas/prevenção & controle , Extratos Celulares/administração & dosagem , Hospedeiro Imunocomprometido , Fatores Imunológicos/administração & dosagem , Imunossupressores/efeitos adversos , Nefrose/complicações , Adolescente , Adulto , Anticorpos/sangue , Doenças Autoimunes/tratamento farmacológico , Infecções Bacterianas/epidemiologia , Feminino , Humanos , Imunossupressores/uso terapêutico , Incidência , Contagem de Leucócitos , Masculino , Nefrose/tratamento farmacológico , Resultado do Tratamento , Adulto Jovem
14.
J Huazhong Univ Sci Technolog Med Sci ; 32(1): 65-68, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22282247

RESUMO

In order to analyze the cai]ses of delayed diagnosis and raise the level of early diagnosis of atypical multiple myeloma (MM), the differences of presenting features between the patients presented to nephrologists and those presented to hematologists were compared. MM patients in our hospital were studied retrospectively. Those who referred renal impairment were divided into two groups: group I presented to nephrologists prior to MM diagnosis (n=29) and group II presented to hematologists directly (n=62). The age, sex, initial symptoms, haematological and biochemical parameters, the phenotype of paraprotein, bone marrow biopsy and cytology were undertaken and analyzed. The results showed that the median time between the initial symptoms and diagnosis in the patients of group I was longer than that in group II (P<0.001); patients in group I had significantly lower incidence of bone pain (P<0.01) and worse renal function (P<0.05) on presentation. There were lower level of myeloma cells (P<0.05), lower incidence of hypergammaglobulinemia (P<0.05), lower positive rate of monoclonal immunoglobulin (M protein) (P<0.05) and M protein level (P<0.05) in the patients of group I than those in group II. The ratio of monoclonal to lambda monoclonal proteins in a population was 1:3.67 in patients of group I, whereas 1:0.90 in patients of group II (P<0.01). Moreover, patients with λ type had a higher degree of renal insufficiency than those with κ type (P<0.05). It was suggested that the median time between the initial symptoms and diagnosis in the patients presented to nephrologists was longer than that in those presented to hematologists; the patients presented to nephrologists had the lower incidence of bone pain, lower level of myeloma cells and M protein, which made early diagnosis more difficult; more patients presented to nephrologists had the majority of λ light chain type, moreover, patients with λ light chain type had a higher incidence of renal insufficiency.


Assuntos
Diagnóstico Tardio/estatística & dados numéricos , Hematologia/estatística & dados numéricos , Nefropatias/diagnóstico , Nefropatias/etiologia , Mieloma Múltiplo/complicações , Mieloma Múltiplo/diagnóstico , Nefrologia/estatística & dados numéricos , Adulto , Distribuição por Idade , Idoso , Idoso de 80 Anos ou mais , China , Diagnóstico Tardio/prevenção & controle , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Distribuição por Sexo
15.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-248560

RESUMO

In order to analyze the causes of delayed diagnosis and raise the level of early diagnosis of atypical multiple myeloma (MM),the differences of presenting features between the patients presented to nephrologists and those presented to hematologists were compared.MM patients in our hospital were studied retrospectively.Those who referred renal impairment were divided into two groups:group Ⅰ presented to nephrologists prior to MM diagnosis (n=29) and group Ⅱ presented to hematologists directly (n=62).The age,sex,initial symptoms,haematological and biochemical parameters,the phenotype of pamprotein,bone marrow biopsy and cytology were undertaken and analyzed.The results showed that the median time between the initial symptoms and diagnosis in the patients of group Ⅰ was longer than that in group Ⅱ (P<0.001); patients in group Ⅰ had significantly lower incidence of bone pain (P<0.01) and worse renal function (P<0.05) on presentation.There were lower level of myeloma cells (P<0.05),lower incidence of hypergammaglobulinemia (P<0.05),lower positive rate of monoclonal immunoglobulin (M protein) (P<0.05) and M protein level (P<0.05) in the patients of group Ⅰ than those in group Ⅱ.The ratio of monoclonal to lambda monoclonal proteins in a population was 1:3.67 in patients of group Ⅰ,whereas 1∶0.90 in patients of group Ⅱ (P<0.0 l).Moreover,patients with λ type had a higher degree of renal insufficiency than those with κ type (P<0.05).It was suggested that the median time between the initial symptoms and diagnosis in the patients presented to nephrologists was longer than that in those presented to hematologists; the patients presented to nephrologists had the lower incidence of bone pain,lower level of myeloma cells and M protein,which made early diagnosis more difficult; more patients presented to nephrologists had the majority of λ light chain type,moreover,patients with λ light chain type had a higher incidence of renal insufficiency.

16.
IEEE Trans Neural Netw ; 22(5): 806-12, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21421436

RESUMO

This paper is concerned with the problem of stability of neural networks with time-varying delays. A novel Lyapunov-Krasovskii functional decomposing the delays in all integral terms is proposed. By exploiting all possible information and considering independent upper bounds of the delay derivative in various delay intervals, some new generalized delay-dependent stability criteria are established, which are different from the existing ones and improve upon previous results. Numerical examples are finally given to demonstrate the effectiveness and the merits of the proposed method.


Assuntos
Inteligência Artificial , Redes Neurais de Computação , Algoritmos , Tempo de Reação , Fatores de Tempo
18.
Artigo em Inglês | MEDLINE | ID: mdl-16196290

RESUMO

To study the efficacy and the mechanism of Colquhoumia root (Tripterygium hypoglaucum (Le,vL) Hutch) in the treatment of mesangial proliferation glomerulonephritis (MsPGN), SD rats were injected with anti-thymocyte serum (ATS) to make MsPGN model (anti-Thyl model). The rats were then divided into 3 groups: normal control group, anti-Thyl model group and treatment group. Histopathological (HE, PAS), immunohistochemical, RT-PCR technique and computer imaging analysis system were used to evaluate mesangial matrix production, the expression of TGF-beta1 protein and mRNA in the tissues of kidney. Our result showed that proteinuria and the ratio of extracellular matrix/glomerular capillaries area (ECM/CA) were increased significantly in model group. The expression of both TGF-beta1 protein and mRNA in glomeruli was much higher in model group than in control group (P < 0.01). After the treatment with Colquhoumia root, proteinuria, ECM/CA and the expression of both TGF-beta1 protein and mRNA in glomeruli were significantly decreased in treatment group as compared with those in model group. It is concluded that Colquhoumia root is effective in reducing proteinuria and mesangial matrix proliferation in MsPGN and it may achieve these effects by inhibiting the expressions of TGF-beta1 protein and mRNA of mesangial cells.


Assuntos
Glomerulonefrite Membranoproliferativa/tratamento farmacológico , Glomerulonefrite Membranoproliferativa/metabolismo , Fitoterapia , Fator de Crescimento Transformador beta/biossíntese , Tripterygium , Animais , Medicamentos de Ervas Chinesas/uso terapêutico , Glomerulonefrite Membranoproliferativa/etiologia , Isoanticorpos , Masculino , Raízes de Plantas , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Coelhos , Ratos , Ratos Sprague-Dawley , Fator de Crescimento Transformador beta/genética
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