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1.
J Med Virol ; 95(10): e29132, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37792307

RESUMO

Esophageal squamous cell carcinoma (ESCC) may be correlated with HPV infection, and the mechanism underlying the ESCC formation induced by HPV16 infection remains elusive. Here, we overexpressed HPV16 E6 and E7 and coordinated the overexpression of these two genes in EPC2 and ESCC cells. We found that E7 and coordinated expression of E6 and E7 promoted the proliferation of EPC2 cells, and upregulation of shh was responsible for cell proliferation since the use of vismodegib led to the failure of organoid formation. Meanwhile, overexpression of E6 and E7 in ESCC cells promoted cell proliferation, migration, and invasion in vitro. Importantly, E6 and E7 coordinately increased the capability of tumor growth in nude mice, while vismodegib slowed the growth of tumors in NCG mice. Moreover, a series of genes and proteins changed in cell lines after overexpression of the E6 and E7 genes, the potential biological processes and pathways were systematically analyzed using a bioinformatics assay. Together, these findings suggest that the activation of the hedgehog pathway induced by HPV16 infection may initially transform basal cells in the esophagus and promote following malignant processes in ESCC cells. The application of hedgehog inhibitors may represent a therapeutic avenue for ESCC treatment.


Assuntos
Neoplasias Esofágicas , Carcinoma de Células Escamosas do Esôfago , Infecções por Papillomavirus , Animais , Camundongos , Proteínas Hedgehog/genética , Carcinoma de Células Escamosas do Esôfago/genética , Papillomavirus Humano 16/genética , Infecções por Papillomavirus/complicações , Neoplasias Esofágicas/genética , Camundongos Nus
2.
Molecules ; 28(5)2023 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-36903313

RESUMO

Atrazine is a toxic and refractory herbicide that poses threats to human health and the ecological environment. In order to efficiently remove atrazine from water, a novel material, Co/Zr@AC, was developed. This novel material is prepared by loading two metal elements, cobalt and zirconium, onto activated carbon (AC) through solution impregnation and high-temperature calcination. The morphology and structure of the modified material were characterized, and its ability to remove atrazine was evaluated. The results showed that Co/Zr@AC had a large specific surface area and formed new adsorption functional groups when the mass fraction ratio of Co2+:Zr4+ in the impregnating solution was 1:2, the immersion time was 5.0 h, the calcination temperature was 500 °C, and the calcination time was 4.0 h. During the adsorption experiment on 10 mg/L atrazine, the maximum adsorption capacity of Co/Zr@AC was shown to be 112.75 mg/g and the maximum removal rate was shown to be 97.5% after 90 min of the reaction at a solution pH of 4.0, temperature of 25 °C, and Co/Zr@AC concentration of 60.0 mg/L. In the kinetic study, the adsorption followed the pseudo-second-order kinetic model (R2 = 0.999). The fitting effects of Langmuir and Freundlich isotherms were excellent, indicating that the process of Co/Zr@AC adsorbing atrazine also conformed to two isotherm models, so the adsorption of atrazine by Co/Zr@AC had multiple effects including chemical adsorption, mono-molecular layer adsorption, and multi-molecular layer adsorption. After five experimental cycles, the atrazine removal rate was 93.9%, indicating that Co/Zr@AC is stable in water and is an excellent novel material that can be used repeatedly.

3.
Opt Express ; 28(21): 31197-31208, 2020 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-33115098

RESUMO

Three-dimensional (3D) shape measurement based on the fringe projection technique has been extensively used for scientific discoveries and industrial practices. Yet, one of the most challenging issues is its limited depth of field (DOF). This paper presents a method to drastically increase DOF of 3D shape measurement technique by employing the focal sweep method. The proposed method employs an electrically tunable lens (ETL) to rapidly sweep the focal plane during image integration and the post deconvolution algorithm to reconstruct focused images for 3D reconstruction. Experimental results demonstrated that our proposed method can achieve high-resolution and high-accuracy 3D shape measurement with greatly improved DOF in real time.

5.
Cardiovasc Drugs Ther ; 33(1): 45-54, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30675709

RESUMO

Myocardial ischemia/reperfusion (I/R) injury is a serious threat to the health of people around the world. Recent evidence has indicated that high-mobility group box-1 (HMGB1) is involved in I/R-induced inflammation, and inflammation can cause necroptosis of cells. Interestingly, dexmedetomidine (DEX) has anti-inflammatory properties. Therefore, we speculated that DEX preconditioning may suppress H/R-induced necroptosis by inhibiting expression of HMGB1 in cardiomyocytes. We found that hypoxia/reoxygenation (H/R) significantly increased cellular damage, as measured by cell viability (100 ± 3.26% vs. 53.33 ± 3.29, p < 0.01), CK-MB (1 vs. 3.25 ± 0.26, p < 0.01), cTnI (1 vs. 2.69 ± 0.31, p < 0.01), inflammation as indicated by TNF-α (1 ± 0.09 vs. 2.57 ± 0.12, p < 0.01), IL-1ß (1 ± 0.33 vs. 3.87 ± 0.41, p < 0.01) and IL-6 (1 ± 0.36 vs. 3.60 ± 0.45, p < 0.01), and necroptosis, which were accompanied by significantly increased protein levels of HMGB1. These changes [cellular damage as measured by cell viability (53.33 ± 3.29% vs. 67.59 ± 2.69%, p < 0.01), CK-MB (3.25 ± 0.26 vs. 2.27 ± 0.22, p < 0.01), cTnI (2.69 ± 0.31 vs. 1.90 ± 0.25, p < 0.01), inflammation as indicated by TNF-α (2.57 ± 0.12 vs. 1.75 ± 0.15, p < 0.01), IL-1ß (3.87 ± 0.41 vs. 2.09 ± 0.36, p < 0.01) and IL-6 (3.60 ± 0.45 vs. 2.21 ± 0.39, p < 0.01), and necroptosis proteins] were inhibited by DEX preconditioning. We also found that silencing expression of HMGB1 reinforced the protective effects of DEX preconditioning and overexpression of HMGB1 counteracted the protective effects of DEX preconditioning. Thus, we concluded that DEX preconditioning inhibits H/R-induced necroptosis by inhibiting expression of HMGB1 in cardiomyocytes.


Assuntos
Anti-Inflamatórios/farmacologia , Dexmedetomidina/farmacologia , Proteína HMGB1/antagonistas & inibidores , Mediadores da Inflamação/antagonistas & inibidores , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Miócitos Cardíacos/efeitos dos fármacos , Animais , Morte Celular/efeitos dos fármacos , Hipóxia Celular , Linhagem Celular , Microambiente Celular , Citocinas/metabolismo , Proteína HMGB1/genética , Proteína HMGB1/metabolismo , Mediadores da Inflamação/metabolismo , Traumatismo por Reperfusão Miocárdica/metabolismo , Traumatismo por Reperfusão Miocárdica/patologia , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Ratos , Transdução de Sinais/efeitos dos fármacos
6.
Sensors (Basel) ; 20(1)2019 Dec 25.
Artigo em Inglês | MEDLINE | ID: mdl-31881769

RESUMO

Insufficient power supply is a huge challenge for wireless body area network (WBAN). Body channel wireless power transfer (BC-WPT) is promising to realize multi-node high-efficiency power transmission for miniaturized WBAN nodes. However, the behavior of BC-WPT, especially in the multi-node scenario, is still lacking in research. In this paper, the inter-degeneration mechanism of a multi-node BC-WPT is investigated based on the intuitive analysis of the existing circuit model. Co-simulation in the Computer Simulation Technology (CST) and Cadence platform and experiments in a general indoor environment verify this mechanism. Three key factors, including the distance between the source and the harvester, frequency of the source, and area of the ground electrodes, are taken into consideration, resulting in 15 representative cases for simulation and experiments studies. Based on the simulation parameters, an empirical circuit model to accurately predict the received power of multiple harvesters is established, which fits well with the measurement results, and can further provide guidelines for designs and research on multi-node BC-WPT systems.

7.
Gastrointest Endosc ; 78(2): 277-84, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23528652

RESUMO

BACKGROUND: The use of various kinds of metal stents has emerged as an effective palliative treatment for malignant gastric outlet obstruction (GOO). However, most of these metal stents were designed for use in the esophagus or intestine and have a high incidence of stent obstruction and stent migration when used elsewhere. OBJECTIVE: To evaluate the efficacy and safety of individualized stents (designed according to the shape and size of the GOO) in order to determine whether such stents could reduce the incidence of stent obstruction and migration. DESIGN: Multicenter, prospective, clinical trial. SETTING: Two tertiary-care referral centers. PATIENTS: Thirty-seven patients who presented with symptomatic unresectable malignant GOO caused by distal gastric cancer between April 2005 and June 2009. INTERVENTION: Placement of the individualized metal stents. MAIN OUTCOME MEASUREMENTS: The primary endpoint was to optimize stent resolution of proximal obstruction as determined by a GOO scoring system. Secondary endpoints were success rates, survival rates, and adverse events. RESULTS: Technical and clinical success was achieved in 97.3% and 94.4% of patients, respectively. The rate of resolution of proximal obstruction by a proximal stent was 97.3%. There were no procedure-related perforations or deaths. No stent migration or obstruction by tumor growth were found. The mean survival time was 232 days (range 28-387 days). LIMITATIONS: A single-arm study in tertiary-care centers. CONCLUSION: Placement of individualized stents is a safe and effective modality for the palliation of malignant GOO caused by distal stomach cancer and can help reduce tumor ingrowth and stent migration.


Assuntos
Adenocarcinoma/patologia , Obstrução da Saída Gástrica/cirurgia , Cuidados Paliativos/métodos , Stents , Neoplasias Gástricas/patologia , Adenocarcinoma/complicações , Idoso , Idoso de 80 Anos ou mais , Desenho de Equipamento , Feminino , Obstrução da Saída Gástrica/etiologia , Humanos , Masculino , Metais , Neoplasias Gástricas/complicações , Resultado do Tratamento
8.
World J Clin Cases ; 11(8): 1782-1787, 2023 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-36969998

RESUMO

BACKGROUND: Solitary hamartomatous polyps (SHPs) are rare lesions. Endoscopic full-thickness resection (EFTR) is a highly efficient and minimally invasive endoscopic procedure that benefits from complete lesion removal and high safety. CASE SUMMARY: A 47-year-old man was admitted to our hospital after experiencing hypogastric pain and constipation for over fifteen days. Computed tomography and endoscopy revealed a giant pedunculated polyp (approximately 18 cm long) in the descending and sigmoid colon. This is the largest SHP reported to date. Having considered the condition of the patient and mass growth, the polyp was removed using EFTR. CONCLUSION: On the basis of clinical and pathological evaluations, the mass was considered an SHP.

9.
Cell Death Discov ; 9(1): 399, 2023 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-37891174

RESUMO

Emerging evidence indicates that SOX2 is an oncogene for esophageal squamous cell carcinoma (ESCC). However, direct targeting of SOX2 is not feasible given that this transcription factor plays important roles in the maintenance of tissues such as the brain. Here, we identified CDP (Homeobox protein cut-like 1 or CASP) as a unique SOX2 binding partner enriched in ESCC with Duolink proximity ligation assay, bimolecular fluorescence complementation (BiFc) and immunoprecipitation. We then screened a peptide aptamer library using BiFc and immunoprecipitation and identified several peptide aptamers, including P58, that blocked the CDP/SOX2 interaction, leading to the inhibition of ESCC progress in vitro and in vivo. Upon administration, synthetic peptide P58, containing the YGRKKRRQRRR cell-penetrating peptide and the fluorophore TAMRA, also blocked the growth and metastasis of ESCC in both mice and zebrafish. Therefore, targeting the SOX2 binding partner CDP with peptide P58 offers an alternative avenue to treat ESCC with increased SOX2 levels.

10.
Front Cell Infect Microbiol ; 12: 962782, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35903197

RESUMO

Intestinal ischemia/reperfusion (II/R) is a common acute and critical condition in clinical practice with a high mortality rate. However, there is still a lack of effective prevention and treatment measures for II/R injury. The role of the gut microbiota in II/R has attracted widespread attention. Recent evidence has demonstrated that the gut microbiota plays a pivotal role in the occurrence, development, and prognosis of II/R. Therefore, maintaining the homeostasis of gut microbiota and its metabolites may be a potential strategy for the treatment of II/R. This review focuses on the importance of crosstalk between the gastrointestinal ecosystem and II/R to highlight II/R-induced gut microbiota signatures and potential applications of microbial-based therapies in II/R. This will also provide potentially effective biomarkers for the prediction, diagnosis and treatment of II/R.


Assuntos
Microbioma Gastrointestinal , Traumatismo por Reperfusão , Disbiose/complicações , Ecossistema , Humanos , Isquemia/complicações , Traumatismo por Reperfusão/complicações , Traumatismo por Reperfusão/tratamento farmacológico
11.
IEEE Trans Neural Netw Learn Syst ; 33(5): 2259-2273, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-33587706

RESUMO

Weight pruning methods of deep neural networks (DNNs) have been demonstrated to achieve a good model pruning rate without loss of accuracy, thereby alleviating the significant computation/storage requirements of large-scale DNNs. Structured weight pruning methods have been proposed to overcome the limitation of irregular network structure and demonstrated actual GPU acceleration. However, in prior work, the pruning rate (degree of sparsity) and GPU acceleration are limited (to less than 50%) when accuracy needs to be maintained. In this work, we overcome these limitations by proposing a unified, systematic framework of structured weight pruning for DNNs. It is a framework that can be used to induce different types of structured sparsity, such as filterwise, channelwise, and shapewise sparsity, as well as nonstructured sparsity. The proposed framework incorporates stochastic gradient descent (SGD; or ADAM) with alternating direction method of multipliers (ADMM) and can be understood as a dynamic regularization method in which the regularization target is analytically updated in each iteration. Leveraging special characteristics of ADMM, we further propose a progressive, multistep weight pruning framework and a network purification and unused path removal procedure, in order to achieve higher pruning rate without accuracy loss. Without loss of accuracy on the AlexNet model, we achieve 2.58× and 3.65× average measured speedup on two GPUs, clearly outperforming the prior work. The average speedups reach 3.15× and 8.52× when allowing a moderate accuracy loss of 2%. In this case, the model compression for convolutional layers is 15.0× , corresponding to 11.93× measured CPU speedup. As another example, for the ResNet-18 model on the CIFAR-10 data set, we achieve an unprecedented 54.2× structured pruning rate on CONV layers. This is 32× higher pruning rate compared with recent work and can further translate into 7.6× inference time speedup on the Adreno 640 mobile GPU compared with the original, unpruned DNN model. We share our codes and models at the link http://bit.ly/2M0V7DO.


Assuntos
Compressão de Dados , Redes Neurais de Computação , Compressão de Dados/métodos
12.
Int J Biol Sci ; 18(2): 858-872, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35002530

RESUMO

Myocardial ischemia/reperfusion (I/R) injury is still a lack of effective therapeutic drugs, and its molecular mechanism is urgently needed. Studies have shown that the intestinal flora plays an important regulatory role in cardiovascular injury, but the specific mechanism has not been fully elucidated. In this study, we found that an increase in Ang II in plasma was accompanied by an increase in the levels of myocardial injury during myocardial reperfusion in patients with cardiopulmonary bypass. Furthermore, Ang II treatment enhanced mice myocardial I/R injury, which was reversed by caveolin-1 (CAV-1)-shRNA or strengthened by angiotensin-converting enzyme 2 (ACE2)-shRNA. The results showed that CAV-1 and ACE2 have protein interactions and inhibit each other's expression. In addition, propionate, a bacterial metabolite, inhibited the elevation of Ang II and myocardial injury, while GPR41-shRNA abolished the protective effects of propionate on myocardial I/R injury. Clinically, the propionate content in the patient's preoperative stool was related to Ang II levels and myocardial I/R injury levels during myocardial reperfusion. Taken together, propionate alleviates myocardial I/R injury aggravated by Ang II dependent on CAV-1/ACE2 axis through GPR41, which provides a new direction that diet to regulate the intestinal flora for treatment of myocardial I/R injury.


Assuntos
Caveolina 1/metabolismo , Traumatismo por Reperfusão Miocárdica/tratamento farmacológico , Miocárdio/metabolismo , Propionatos/farmacologia , Receptores Acoplados a Proteínas G/metabolismo , Enzima de Conversão de Angiotensina 2/metabolismo , Animais , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Traumatismo por Reperfusão Miocárdica/metabolismo , Miocárdio/patologia , Sistema Renina-Angiotensina/efeitos dos fármacos
13.
Mol Biol Rep ; 38(3): 1909-14, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20845074

RESUMO

Penehyclidine hydrochloride (PHC) is a new anticholinergic drug. PHC has been shown to have a good curative effect for sepsis. Mitogen-activated protein kinase (MAPK) has recently been considered to play an important role in sepsis. In this study, the role of MAPK signal pathways in protective effects of PHC preconditioning on acute lung injury in cecal ligation and puncture (CLP)-induced sepsis was investigated. Healthy female mice were randomly divided into 4 groups: sham control, CLP, and 0.3 or 0.45 mg/kg PHC. At 12 h after surgery, arterial blood was drawn for blood gas analysis, and lung tissue samples were collected to examine pulmonary microvascular permeability, IL-6 levels and myeloperoxidase (MPO) activity. MAPK protein expressions were measured using western blot technique. Compared with sham control mice, acute lung injury was induced in CLP group, which was indicated by decreased PaO(2)/FiO(2), increased pulmonary microvascular permeability, IL-6 levels and MPO activity. Furthermore, mice' exposure to CLP induced the increased protein levels of MAPK. Treatment of 0.45 mg/kg PHC markedly improved PaO(2)/FiO(2), decreased pulmonary microvascular permeability, IL-6 levels and MPO activity, and inhibited expressions of extracellular signal-regulated kinase (ERK1/2) and p38 MAPK. Taken together, these results suggest that PHC ameliorated acute lung injury through the inhibition of extracellular signal-regulated kinase (ERK1/2) and p38 MAPK activation in septic mice.


Assuntos
Lesão Pulmonar Aguda/enzimologia , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Quinuclidinas/farmacologia , Lesão Pulmonar Aguda/induzido quimicamente , Lesão Pulmonar Aguda/patologia , Animais , Permeabilidade Capilar/efeitos dos fármacos , Ceco/efeitos dos fármacos , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Feminino , Interleucina-6/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Ligadura , Pulmão/irrigação sanguínea , Pulmão/efeitos dos fármacos , Pulmão/enzimologia , Pulmão/patologia , Camundongos , Microvasos/efeitos dos fármacos , Microvasos/patologia , Oxigênio/metabolismo , Peroxidase/metabolismo , Fosforilação/efeitos dos fármacos , Punções , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
14.
Sensors (Basel) ; 10(4): 3195-217, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-22319294

RESUMO

Energy is an important consideration in wireless sensor networks. In the current compression evaluations, traditional indices are still used, while energy efficiency is probably neglected. Moreover, various evaluation biases significantly affect the final results. All these factors lead to a subjective evaluation. In this paper, a new criterion is proposed and a series of tunable compression algorithms are reevaluated. The results show that the new criterion makes the evaluation more objective. Additionally it indicates the situations when compression is unnecessary. A new adaptive compression arbitration system is proposed based on the evaluation results, which improves the performance of compression algorithms.

15.
Gastroenterol Res Pract ; 2019: 8093091, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31354809

RESUMO

OBJECTIVES: This study is aimed at evaluating the efficacy and safety of the big end double-layer uncovered self-expanding metal stents (SEMS) for the treatment of gastric outlet obstruction (GOO) caused by distal stomach cancer. METHODS: Seventy three patients receiving big end double-layer uncovered SEMS for the treatment of GOO caused by distal gastric cancer will be included in this multicenter prospective clinical trial. The main outcome measures included the functional outcome, the complications, the reinterventional rates, the average treatment charges, and the mean survival time. Monthly telephone calls were needed to assess the food intake until the patients died. RESULTS: The technical and the clinical success rates were 98.6%. The stent obstruction caused by tumor ingrowth was observed in one patient (1.4%). The incidence of food impaction was 2.9% (2/70) and the reinterventional rate was 4.3% (3/70). However, stent migration and obstruction caused by overgrowth were not observed. No perforation and severe bleeding were observed. The median cost of endoscopic stenting and total hospitalization (including reinterventions) for the big end double-layer uncovered SEMS in this study was $2945 and $3408, respectively. The mean survival time was 212.5 days. CONCLUSIONS: The placement of big end double-layer uncovered SEMS is a safe and effective modality and has the potential to be one of the options for the treatment of GOO caused by the distal gastric cancer.

16.
Sci Rep ; 9(1): 8880, 2019 06 20.
Artigo em Inglês | MEDLINE | ID: mdl-31222038

RESUMO

In this study, the adsorption and UV photocatalytic degradation of atrazine using nano-TiO2 particles were studied systematically, and the colloidal stability of nano-TiO2 particles in solution was also investigated to reveal the removal mechanism. Experiments which contained the first 6.0 hours darkness and 4.0 hours UV illumination later were conducted at different concentrations of Ca2+ and/or fulvic acids (FA) at pH = 7.0. Results showed that the adsorption rate of atrazine onto nano-TiO2 particles decreased with the increase of Ca2+ and/or FA concentrations, which could be explained well by the colloidal stability of nanoparticles. When the solution contained Ca2+ or Ca2+-FA, the nanoparticles were aggregated together leading to the decrease of the contact surface area. Besides, there existed competitive adsorption between FA and atrazine on the particle surface. During photocatalytic degradation, the increase of Ca2+ and/or FA concentration accelerated the aggregation of nano-TiO2 particles and that reduced the degradation efficiency of atrazine. The particle sizes by SEM were in accordance with the aggregation degree of nanoparticles in the solutions. Sedimentation experiments of nano-TiO2 particles displayed that the fastest sedimentation was happened in the CaCl2 and FA coexistent system and followed by CaCl2 alone, and the results well demonstrated the photodegradation efficiency trends of atrazine by nano-TiO2 particles under the different sedimentation conditions.

17.
Artigo em Inglês | MEDLINE | ID: mdl-31888127

RESUMO

Atrazine is a kind of triazine herbicide that is widely used for weed control due to its good weeding effect and low price. The study of atrazine removal from the environment is of great significance due to the stable structure, difficult degradation, long residence time in environment, and toxicity on the organism and human beings. Therefore, a number of processing technologies are developed and widely employed for atrazine degradation, such as adsorption, photochemical catalysis, biodegradation, etc. In this article, with our previous research work, the progresses of researches about the treatment technology of atrazine are systematically reviewed, which includes the four main aspects of physicochemical, chemical, biological, and material-microbial-integrated aspects. The advantages and disadvantages of various methods are summarized and the degradation mechanisms are also evaluated. Specially, recent advanced technologies, both plant-microbial remediation and the material-microbial-integrated method, have been highlighted on atrazine degradation. Among them, the plant-microbial remediation is based on the combined system of soil-plant-microbes, and the material-microbial-integrated method is based on the synergistic effect of materials and microorganisms. Additionally, future research needs to focus on the excellent removal effect and low environmental impact of functional materials, and the coordination processing of two or more technologies for atrazine removal is also highlighted.


Assuntos
Atrazina/química , Biodegradação Ambiental , Herbicidas/química , Plantas/química , Microbiologia do Solo , Poluentes do Solo/química
18.
IEEE Trans Biomed Circuits Syst ; 13(4): 735-745, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31107661

RESUMO

Body channel communication (BCC) has the potential to achieve better energy efficiency over other conventional wireless communication schemes, thus becomes a promising solution for the wireless body area network. To deal with the fading and dynamic variation challenges of BCC, the technique of orthogonal frequency-division multiplexing (OFDM) is a promising candidate. However, some basic issues in OFDM including the pilot design and the modulating methods have not been analyzed for BCC. The contribution of this paper includes proposing a dynamic channel model of BCC for system level designing, analyzing the pilot design method, and proposing an adaptive modulating algorithm for BCC. Practical communication experiments based on software define radio are also implemented to validate the the effectiveness of the pilot design method and the modulating algorithm.


Assuntos
Algoritmos , Capacitância Elétrica , Modelos Teóricos , Tecnologia sem Fio , Simulação por Computador , Método de Monte Carlo , Processamento de Sinais Assistido por Computador , Caminhada
19.
IEEE Trans Biomed Circuits Syst ; 13(4): 756-765, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31226086

RESUMO

This paper proposes an auto loss compensation (ALC) system to attenuate the time-variant path loss for capacitive-coupled body channel communication (CC-BCC). The system employs a time-division gradient indicator to continuously monitor the compensation conditions, and dynamically adjust the compensation inductor through a proportional integral (PI) controller. With the closed-loop topology, the proposed ALC system has two major advantages: first, the path loss induced by the backward coupling effect can be compensated without calibration; second, this system can dynamically attenuate the path loss, even when the channel characteristics vary with time. The simulation and experimental results show that the proposed ALC system can significantly attenuate the backward path loss, especially under wearable and motion scenarios.


Assuntos
Algoritmos , Capacitância Elétrica , Corpo Humano , Tecnologia sem Fio , Simulação por Computador , Gestos , Humanos , Movimento (Física) , Dinâmica não Linear , Análise de Ondaletas
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