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1.
mSphere ; 9(8): e0038624, 2024 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-39105581

RESUMO

Arthropods harbor complex microbiota that play a pivotal role in host fitness. While multiple factors, like host species and diet, shape microbiota in arthropods, their impact on community assembly in wild insects remains largely unknown. In this study, we surveyed bacterial and fungal community assembly in nine sympatric wild insect species that share a common citrus fruit diet. Source tracking analysis suggested that these insects acquire some bacteria and fungi from the citrus fruit with varying degrees. Although sharing a common diet led to microbiota convergence, the diversity, composition, and network of both bacterial and fungal communities varied significantly among surveyed insect groups. Null model analysis indicated that stochastic processes, particularly dispersal limitation and drift, are primary drivers of structuring insect bacterial and fungal communities. Importantly, the influence of each community assembly process varied strongly depending on the host species. Thus, we proposed a speculative view that the host specificity of the microbiome and mycobiome assembly is widespread in wild insects despite sharing the same regional species pool. Overall, this research solidifies the importance of host species in shaping microbiomes and mycobiomes, providing novel insights into their assembly mechanisms in wild insects. IMPORTANCE: Since the microbiome has been shown to impact insect fitness, a mechanistic understanding of community assembly has potentially significant applications but remains largely unexplored. In this paper, we investigate bacterial and fungal community assembly in nine sympatric wild insect species that share a common diet. The main findings indicate that stochastic processes drive the divergence of microbiomes and mycobiomes in nine sympatric wild insect species. These findings offer novel insights into the assembly mechanisms of microbiomes and mycobiomes in wild insects.


Assuntos
Bactérias , Dieta , Fungos , Insetos , Microbiota , Processos Estocásticos , Simpatria , Animais , Insetos/microbiologia , Fungos/classificação , Fungos/genética , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Micobioma , Citrus/microbiologia
2.
Front Microbiol ; 15: 1424568, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39091307

RESUMO

Environmental heterogeneity partly drives microbial succession in arthropods, while the microbial assembly mechanisms during environmental changes remain largely unknown. Here, we explored the temporal dynamics and assembly mechanisms within both bacterial and fungal communities in Liriomyza huidobrensis (Blanchard) during the transition from field to laboratory conditions. We observed a decrease in bacterial diversity and complexity of bacterial-fungal co-occurrence networks in leaf miners transitioning from wild to captive environments. Both neutral and null models revealed that stochastic processes, particularly drift (contributing over 70%), play a crucial role in governing bacterial and fungal community assembly. The relative contribution of ecological processes such as dispersal, drift, and selection varied among leaf miners transitioning from wild to captive states. Furthermore, we propose a hypothetical scenario for the assembly and succession of microbial communities in the leaf miner during the short- and long-term transition from the wild to captivity. Our findings suggest that environmental heterogeneity determines the ecological processes governing bacterial and fungal community assembly in leaf miners, offering new insights into microbiome and mycobiome assembly mechanisms in invasive pests amidst environmental change.

3.
Clin Exp Med ; 24(1): 194, 2024 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-39153102

RESUMO

To compare clinical characteristics and survival outcomes of patients with multiple renal cell carcinoma versus single renal cell carcinoma. Develop a prognostic model for predicting prognosis in patients with multiple tumors and analyze prognostic factors. Patients with primary multiple renal cell carcinoma were selected from the Surveillance, Epidemiology, and End Results database (2004-2015). They were divided into single-tumor and multiple-tumor groups. Survival analysis was conducted using the Kaplan-Meier method and log-rank test. A Cox regression model was used to identify potential prognostic factors. A total of 19,489 renal cell carcinoma cases were included, with 947 in the multiple-tumor group and 18,542 in the single-tumor group. The multiple-tumor group had lower cancer-specific survival (P = 0.03, HR = 1.431). Cox regression identified risk factors for the multiple-tumor group including number of tumors, gender, combined summary stage, T stage, N stage, tumor size, and type of surgery. The predicted probabilities showed acceptable agreement with the actual observations at 3-, 5-, and 8-years area under the curve values in both the training and validation cohorts (0.831 vs. 0.605; 0.775 vs. 0.672; and 0.797 vs. 0.699, respectively). Compared with single renal cell carcinoma, multiple renal cell carcinoma is associated with decreased cancer-specific survival. Additionally, we identified several prognostic factors including the number of tumors, T stage, tumor size, and type of surgery. These findings offer valuable insights for selecting appropriate treatment strategies for patients diagnosed with multiple renal cell carcinomas.


Assuntos
Carcinoma de Células Renais , Neoplasias Renais , Programa de SEER , Humanos , Carcinoma de Células Renais/patologia , Carcinoma de Células Renais/mortalidade , Masculino , Feminino , Prognóstico , Pessoa de Meia-Idade , Neoplasias Renais/patologia , Neoplasias Renais/mortalidade , Neoplasias Renais/cirurgia , Idoso , Análise de Sobrevida , Estimativa de Kaplan-Meier , Neoplasias Primárias Múltiplas/patologia , Neoplasias Primárias Múltiplas/mortalidade , Estadiamento de Neoplasias , Adulto , Fatores de Risco , Idoso de 80 Anos ou mais , Modelos de Riscos Proporcionais
4.
Environ Pollut ; 361: 124825, 2024 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-39197646

RESUMO

Tris(2-chloroethyl) phosphate (TCEP) is of growing public concern worldwide because of its ubiquitous contamination, toxicity, and persistence. In this study, we investigated bacterial communities in aerobic enrichment cultures with TCEP and its two major transformation products bis(2-chloroethyl) phosphate (BCEP) and 2-chloroethanol (2-CE) as the sole carbon source. Burkholderiales and Rhizobiales were likely two main bacterial guilds involved in the hydrolysis of TCEP, while Rhizobiales and Sphingomonadales may play an important role in the hydrolysis of BCEP, given the increase of Rhizobiales and Sphingomonadales-related phosphoesterase genes when the carbon source was switched from TCEP to BCEP. All Burkholderiales, Rhizobiales, Sphingomonadales were probably efficient in 2-CE metabolism, because their dehydrogenase genes and dehalogenase genes increased after 2-CE enrichment. The different substrate preference of different bacterial guilds highlighted the importance to understand the diversity and collaboration among functional bacteria. Meanwhile, two TCEP-degrading strains affiliated with Xanthobacter and Ancylobacter were isolated. Xanthobacter sp. strain T2-1 was able to degrade both TCEP and BCEP following the pseudo-first-order kinetics with reaction rates of 1.66 h-1 for TCEP and 1.02 h-1 for BCEP, respectively. Ancylobacter sp. strain T3-4 could degrade TCEP following the pseudo-first-order kinetics with a reaction rate of 2.54 h-1, but is unable to degrade BCEP. Additionally, strains that were phylogenetically closely related were found to have different degradation capabilities toward TCEP and/or BCEP, indicating the importance to investigate functional genes such as phosphoesterase genes.

5.
J Mater Chem B ; 12(32): 7870-7878, 2024 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-39011592

RESUMO

Aiming to decrease the recurrence of tumors and achieve patient satisfaction, the elicitation of immunotherapy and its integrated synergistic employment is a bright new direction in oncotherapy, yet an emergently challenging task. In particular, tumor-associated macrophage (TAM) regulation though light-induced photodynamic and photothermal therapy (PDT and PTT) is regarded as a powerful approach, which focuses on the systemic immune system instead of the tumor itself. Herein, this study reports an acceptor-donor-acceptor (A-D-A) aggregation-induced emission luminogen (AIEgen), named TPA-2CN, which was applied as a photosensitizer (PS) and photothermal agent (PTA). Attributed to its A-D-A structure and AIE properties, TPA-2CN exhibits a high molar absorption coefficient and acts as a perfect template in regulating radiative and nonradiative transitions, which mainly utilize excited energy. The generation of type I reactive oxygen promoted its application in hypoxic tumor sites and the combination of hyperpyrexia forcefully induces macrophages to polarize towards the immune response M1 phenotype. In in vitro and in vivo, the successful reversion and reprogramming of the immune microenvironment was impressively proved. This method optimally concentrated immune therapy, PDT and PTT as one and exhibited excellent synergistic therapeutic effects with good biosafety.


Assuntos
Fármacos Fotossensibilizantes , Macrófagos Associados a Tumor , Animais , Camundongos , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/farmacologia , Macrófagos Associados a Tumor/efeitos dos fármacos , Fototerapia/métodos , Humanos , Camundongos Endogâmicos BALB C , Luz , Antineoplásicos/química , Antineoplásicos/farmacologia , Estrutura Molecular , Fotoquimioterapia , Feminino , Tamanho da Partícula , Células RAW 264.7 , Sobrevivência Celular/efeitos dos fármacos
6.
BMC Med Genomics ; 17(1): 121, 2024 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-38702698

RESUMO

BACKGROUND: Kidney renal papillary cell carcinoma (KIRP) is the second most prevalent malignant cancer originating from the renal epithelium. Nowadays, cancer stem cells and stemness-related genes (SRGs) are revealed to play important roles in the carcinogenesis and metastasis of various tumors. Consequently, we aim to investigate the underlying mechanisms of SRGs in KIRP. METHODS: RNA-seq profiles of 141 KIRP samples were downloaded from the TCGA database, based on which we calculated the mRNA expression-based stemness index (mRNAsi). Next, we selected the differentially expressed genes (DEGs) between low- and high-mRNAsi groups. Then, we utilized weighted gene correlation network analysis (WGCNA) and univariate Cox analysis to identify prognostic SRGs. Afterwards, SRGs were included in the multivariate Cox regression analysis to establish a prognostic model. In addition, a regulatory network was constructed by Pearson correlation analysis, incorporating key genes, upstream transcription factors (TFs), and downstream signaling pathways. Finally, we used Connectivity map analysis to identify the potential inhibitors. RESULTS: In total, 1124 genes were characterized as DEGs between low- and high-RNAsi groups. Based on six prognostic SRGs (CCKBR, GPR50, GDNF, SPOCK3, KC877982.1, and MYO15A), a prediction model was established with an area under curve of 0.861. Furthermore, among the TFs, genes, and signaling pathways that had significant correlations, the CBX2-ASPH-Notch signaling pathway was the most significantly correlated. Finally, resveratrol might be a potential inhibitor for KIRP. CONCLUSIONS: We suggested that CBX2 could regulate ASPH through activation of the Notch signaling pathway, which might be correlated with the carcinogenesis, development, and unfavorable prognosis of KIRP.


Assuntos
Carcinoma de Células Renais , Neoplasias Renais , Células-Tronco Neoplásicas , Humanos , Prognóstico , Neoplasias Renais/genética , Neoplasias Renais/patologia , Carcinoma de Células Renais/genética , Carcinoma de Células Renais/patologia , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Regulação Neoplásica da Expressão Gênica , Redes Reguladoras de Genes , Masculino , Biomarcadores Tumorais/genética , Feminino , Perfilação da Expressão Gênica , Pessoa de Meia-Idade , Transdução de Sinais/genética
7.
Small ; : e2400654, 2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38752582

RESUMO

Benefit from the deeper penetration of mechanical wave, ultrasound (US)-based sonodynamic therapy (SDT) executes gratifying efficacy in treating deep-seated tumors. Nevertheless, the complicated mechanism of SDT undeniably hinders the exploration of ingenious sonosensitizers. Herein, a receptor engineering strategy of aggregation-induced emission (AIE) sonosensitizers (TPA-Tpy) with acceptor (A)-donor (D)-A' structure is proposed, which inspects the effect of increased cationizations on US sensitivity. Under US stimulation, enhanced cationization in TPA-Tpy improves intramolecular charge transfer (ICT) and accelerates charge separation, which possesses a non-negligible promotion in type I reactive oxygen species (ROS) production. Moreover, abundant ROS-mediated mitochondrial oxidative stress triggers satisfactory immunogenic cell death (ICD), which further promotes the combination of SDT and ICD. Subsequently, subacid pH-activated nanoparticles (TPA-Tpy NPs) are constructed with charge-converting layer (2,3-dimethylmaleic anhydride-poly (allylamine hydrochloride)-polyethylene glycol (DMMA-PAH-PEG)) and TPA-Tpy, achieving the controllable release of sonosensitizers. In vivo, TPA-Tpy-mediated SDT effectively initiates the surface-exposed of calreticulin (ecto-CRT), dendritic cells (DCs) maturation, and CD8+ T cell infiltration rate through enhanced ROS production, achieving suppression and ablation of primary and metastatic tumors. This study provides new opinions in regulating acceptors with eminent US sensitization, and brings a novel ICD sono-inducer based on SDT to realize superior antitumor effect.

8.
Front Oncol ; 14: 1355551, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38800374

RESUMO

Background: Prostate cancer (PCa) is one of the most threatening health problems for the elderly males. However, our understanding of the disease has been limited by the research technology for a long time. Recently, the maturity of sequencing technology and omics studies has been accelerating the studies of PCa, establishing themselves as an essential impetus in this field. Methods: We assessed Web of Science (WoS) database for publications of sequencing and omics studies in PCa on July 3rd, 2023. Bibliometrix was used to conduct ulterior bibliometric analysis of countries/affiliations, authors, sources, publications, and keywords. Subsequently, purposeful large amounts of literature reading were proceeded to analyze research hotspots in this field. Results: 3325 publications were included in the study. Research associated with sequencing and omics studies in PCa had shown an obvious increase recently. The USA and China were the most productive countries, and harbored close collaboration. CHINNAIYAN AM was identified as the most influential author, and CANCER RESEARCH exhibited huge impact in this field. Highly cited publications and their co-citation relationships were used to filtrate literatures for subsequent literature reading. Based on keyword analysis and large amounts of literature reading, 'the molecular pathogenesis of PCa' and 'the clinical application of sequencing and omics studies in PCa' were summarized as two research hotspots in the field. Conclusion: Sequencing technology had a deep impact on the studies of PCa. Sequencing and omics studies in PCa helped researchers reveal the molecular pathogenesis, and provided new possibilities for the clinical practice of PCa.

9.
Rev Sci Instrum ; 95(4)2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38651990

RESUMO

To reduce harmonic components, balance system impedance, and stabilize driving voltage, an additional matching circuit is required for ultrasonic motors (USMs) driver. However, the performance of inductor or capacitor matching can be seriously weakened with changes in driving frequency. Therefore, this paper presents a simple and effective LC matching method against driving frequency adjustment for USMs. First, the driving scheme of the USM is proposed and the electromechanical coupling model is analyzed. Subsequently, the output characteristics of the full-bridge inverter are derived theoretically when the driving frequency deviates from the mechanical resonant frequency. Then, the impedance circular transform method is proposed, which can intuitively analyze the effect of matching parameters on the voltage amplitude. A matching objective function is established that can consider both the voltage stabilization and harmonic suppression. The matching parameters are solved using random weight particle swarm optimization. Simulations and experiments demonstrate that within the operating frequency of the USM, the proposed matching method can effectively prevent overvoltage and suppress harmonic components. Furthermore, compared with the existing resonant matching method, the proposed matching method can realize more stable driving capability at different frequencies. The proposed method could be useful for USMs' variable-frequency driver design.

10.
ACS Nano ; 18(14): 10184-10195, 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38529933

RESUMO

Heterointerface engineering is an attractive approach to modulating electromagnetic (EM) parameters and EM wave absorption performance. However, the weak interfacial interactions and poor impedance matching would lead to unsatisfactory EM absorption performance due to the limitation of the construction materials and design strategies. Herein, multilevel heterointerface engineering is proposed by in situ growing nanosheet-like NiCoO2 and selenides with abundant interface structures on 3D-printed graphene aerogel (GA) skeletons, which strengthens the interfacial effect and improves the dielectric polarization loss. Benefiting from the features of substantially enhanced polarization loss and optimized impedance matching, the graphene/S-NiCoO2/selenides (G/S-NCO/Se) have achieved brilliant EM wave absorption performance with a strong reflection loss (RL) value of -60.7 dB and a broad effective absorption bandwidth (EAB) of 8 GHz, which is about six times greater than that of the graphene aerogel (-9.8 dB). Moreover, it is further confirmed by charge density differences and off-axis electron holography that a large amount of polarized charge accumulates at the interface, leading to significant polarization relaxation behaviors. This work provides a deep understanding of the effect of a multilevel heterogeneous interface on dielectric polarization loss, which injects a fresh and infinite vitality for designing high-efficiency EM wave absorbers.

11.
Br J Radiol ; 96(1152): 20230495, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37750834

RESUMO

OBJECTIVE: This study aimed to construct an optimal model to predict radiation pneumonia (RP) after radiotherapy for esophageal cancer using unified fractional dosiomics and to investigate the improvements in the prediction efficiency of each model for RP. METHODS: The clinical data, DVH, pre-treatment CT, and dose distribution of 182 patients were retrospectively analyzed.The independent risk factors were screened using univariate and multivariate logistic regression. The mutual information (MI),least absolute shrinkage and selection operator (LASSO), and recursive feature elimination (RFE) methods were used to screen the omics features. The AUC values of ROC, calibration curves, and clinical decision curves were calculated to evaluate the efficacy and trends of each model. RESULTS: The AUC of dosiomics model were 0.783 and 0.760 in the training and test cohorts, higher than 0.585 and 0.579 in the training and test cohorts of the DVH model. The AUC value of the R + D combination was the highest, reaching 0.833. The combined R + D model had a better calibration degree than the other models (mean absolute error = 0.018) and better net benefit in clinical decision-making. CONCLUSIONS: The radiomics combined dosiomics model was the best combined model to predict RP after radiotherapy for esophageal cancer. The dosiomics model could cover the efficiency of the DVH model and significantly improve the efficiency of the combined model.In the future, we will include other centers for further verification. ADVANCES IN KNOWLEDGE: For the first time, this study used CT images combined dose distribution to predict the occurrence of radiation pneumonitis after radiotherapy for esophageal cancer.


Assuntos
Neoplasias Esofágicas , Radioterapia (Especialidade) , Pneumonite por Radiação , Humanos , Pneumonite por Radiação/etiologia , Estudos Retrospectivos , Neoplasias Esofágicas/radioterapia , Calibragem
12.
Br J Radiol ; 96(1152): 20230382, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37750855

RESUMO

OBJECTIVE: The present study aimed to develop the utility of a nomogram based on clinical and radiomics as a tool for predicting post-acute pancreatitis diabetes mellitus (PPDM-A). METHODS: This retrospective investigation evaluated 244 patients with acute pancreatitis. Patients were randomized in a 7:3 ratio into training and validation cohorts. Radiomics feature selection was then achieved using the variance threshold, select best K, and least absolute shrinkage and selection operator methods. The area under the curve values, decision, and calibration curves have been used to determine the models' predictive value. RESULTS: The developed nomogram performed superior to the clinical model in the validation (0.815 vs 0.677, p = 0.016) and training cohorts (0.803 vs 0.683, p = 0.002). The calibration curves demonstrated that the expected and actual values were satisfactory. In contrast, decision curve analysis revealed a stronger relationship between the nomogram and net clinical value than with the distinct radiomics or clinical signature effects. CONCLUSION: In summary, the findings of this study demonstrated that establishing a predictive nomogram as a non-invasive technique may be useful in predicting the risk of PPDM-A. ADVANCES IN KNOWLEDGE: This is the first time to use a CT radiomics nomogram to predict PPDM-A. The nomogram is conducive to the personalized prediction of patients. It only needs to input the patient's information, and a simple addition operation can quantitatively obtain its risk. The resultant tool has the potential to provide new opportunities to treat or prevent PPDM-A more effectively.


Assuntos
Diabetes Mellitus , Pancreatite , Humanos , Doença Aguda , Incidência , Nomogramas , Pancreatite/diagnóstico por imagem , Radiômica , Estudos Retrospectivos , Diabetes Mellitus/epidemiologia , Tomografia Computadorizada por Raios X
13.
ACS Nano ; 17(9): 8420-8432, 2023 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-37073866

RESUMO

Highly conductive MXene material exhibits outstanding dissipation capability of electromagnetic (EM) waves. However, the interfacial impedance mismatch due to high reflectivity restricts the application of MXene-based EM wave absorbing materials. Herein, a direct ink writing (DIW) 3D printing strategy to construct lightweight and stiff MXene/graphene oxide aerogels (SMGAs) with controllable fret architecture is demonstrated, exhibiting tunable EM wave absorption properties by manipulating impedance matching. Noteworthy, the maximum reflection loss variation value (ΔRL) of SMGAs is -61.2 dB by accurately modulating the width of the fret architecture. The effective absorption region (fE) of SMGAs exhibits consecutive multiband tunability, and the broadest tunable fE (Δf) is 14.05 GHz, which could be continuously tuned in the whole C- (4-8 GHz), X- (8-12 GHz), and Ku-bands (12-18 GHz). Importantly, the hierarchical structures and the orderly stacking of filaments endow lightweight SMGAs (0.024 g cm-3) with a surprising compression resistance, which can withstand 36 000 times its own weight without obvious deformation. Finite element analysis (FEA) further indicates that the hierarchical structure facilitates stress dispersion. The strategy developed here provides a method for fabricating tunable MXene-based EM wave absorbers that are lightweight and stiff.

14.
Micromachines (Basel) ; 13(10)2022 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-36295990

RESUMO

To improve suitability in applications with high dynamic performance requirements, the transient response characteristics of high-power piezoelectric transducers should be studied quantitatively. This paper proposes the vector reduction method to solve the complex transient equations and obtains a transient matching scheme clarifying the mechanism of electrical matching resistance on electromechanical damping. A matching scheme with a combination of full-bridge inverter, transformer and series LC circuit is designed and validated, which can provide suitable electrical damping without causing energy losses. Consequently, the experiment verifies the transient properties of the proposed scheme. For a typical piezoelectric cutting transducer with 100.8 ms response time, our scheme is verified to have high dynamic performance within frequency response time of 5.5 ms and vibration response time of 15.0 ms.

15.
Artigo em Inglês | MEDLINE | ID: mdl-34170825

RESUMO

Accurate and fast velocity feedback signal is essential for the velocity control of ultrasonic motors (USMs). However, the low operating velocity of USMs results in a long velocity detection dead time (VDDT) of incremental encoders, which seriously restricts the dynamic control performance of USMs. Therefore, this article presents a super-resolution velocity control (SRVC) scheme based on the velocity reconstruction for the USM. First, the mathematical model of the USM is derived from the mechanical characteristics and the electromechanical coupling characteristics. Then, the velocity reconstruction method is proposed by combining the model estimated velocity and the encoder measured velocity. The closed-loop control scheme using the reconstructed velocity is implemented by a self-designed driving circuit. Experimental results show the velocity reconstruction method not only can break through the limitation of the encoder resolution to reduce the VDDT but also has a high-velocity accuracy. Furthermore, compared with the existing encoder-based control scheme, the proposed SRVC scheme has a faster velocity response under different loads.


Assuntos
Modelos Teóricos , Ultrassom , Retroalimentação
16.
Sensors (Basel) ; 20(22)2020 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-33238569

RESUMO

In some applications of linear ultrasonic motors (LUSMs), not installing speed/position sensors can reduce the size and cost of the system, changes in load will cause fluctuations in the speed of the LUSM. To eliminate the influence of load changes on speed, a speed sensorless control scheme based on stator vibration amplitude compensation (SSCBVC) is proposed. This scheme is implemented under the framework of the stator vibration amplitude-based speed control (VBSC) and frequency tracking. Based on the stator vibration amplitude-speed and the output force-speed curves of the LUSM, the relationship between the load changes and stator vibration amplitude (SVA) to be compensated is established, realizing a speed sensorless control of the LUSM under variable load conditions. The experimental results show that the maximum fluctuation of the speed is about 2.2% when the output force changes from 0 to 6 N with SSCBVC. This scheme can effectively reduce the influence of load changes on the speed of the LUSM without using speed/position sensors.

17.
Med Sci Monit ; 26: e925367, 2020 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-32940255

RESUMO

BACKGROUND Left ventricular assist devices (LVADs) with counter-pulsation mode have been widely used to support left ventricular function and improve coronary circulation. However, the frequency characteristics of the coronary system have not been considered. The aim of this study was to investigate the effects of pulsatile frequency of LVADs on coronary perfusion. MATERIAL AND METHODS First, a lumped parameter (LP) model incorporating coronary circulation, systemic circulation, left heart, and LVAD was established to simulate the cardiovascular system. Then, the frequency characteristics of the coronary system were analyzed and the calculation results showed that the pulsatile frequency of the LVAD has a substantial effect on coronary blood flow. To verify the accuracy of the theoretical analysis, the hemodynamic effects of the LVAD on the coronary artery were compared under 4 support modes: co-pulsation mode, and counter-pulsation modes in synchronization ratios of 1: 1, 2: 1, and 3: 1. RESULTS We found that the coronary flow increased by 5% when the working mode changed from co-pulsation to counter-pulsation in a synchronization ratio of 1: 1, and by an additional 6% when the working mode changed from counter-pulsation in a synchronization ratio of 1: 1 to counter-pulsation in a synchronization ratio of 3: 1. CONCLUSIONS This work provides a useful method to increase coronary perfusion and may be beneficial for improving myocardial function in patients with end-stage heart failure, especially those with ischemic cardiomyopathy (ICM).


Assuntos
Simulação por Computador , Coração Auxiliar , Modelos Cardiovasculares , Função Ventricular Esquerda , Humanos , Reperfusão Miocárdica
18.
Sensors (Basel) ; 20(16)2020 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-32784542

RESUMO

Significant variation in impedance under a wide range of loads increases the difficulty of frequency tracking and vibration control in high-power piezoelectric systems (HPPSs). This paper proposed a wide operating range driving and control scheme for HPPSs. We systematically analyzed the impedance characteristics and deduced the load optimization frequency. In order to provide sufficient drive capability, the inverter combined with an LC matching circuit is configured. With the aid of a transformer ratio arm bridge (TRAB) combined with a proposed pulse-based phase detector (PBPD), the proposed scheme can control the vibration amplitude and keep parallel resonance status under a wide range of loads. Experiments conducted under actual operating conditions verify the feasibility of the proposed scheme under the modal resistance range from 7.40 to 500 Ω and the vibration range from 20% to 100%. Moreover, with the aid of a laser displacement sensor, our scheme is verified to have a vibration amplitude control accuracy better than 2% over a tenfold load variation. This research could be helpful for the driving and control of HPPSs operating in a wide range.

19.
Theranostics ; 10(2): 898-909, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31903158

RESUMO

Gene promoter hypermethylation is a vital step in tumorigenesis. This paper set out to explore the use of polymerase chain reaction - surface-enhanced Raman spectroscopy (PCR-SERS) for the detection of gene methylation levels, with a focus on cancer diagnosis. Methods: PCR with methylation independent primers were used on DNA samples to amplify target genes regardless of their methylation states. SERS was used on the obtained PCR products to generate spectra that contained peak changes belonging to CG and AT base pairs. Multiple linear regression (MLR) was then used to deconvolute the SERS spectra so that the CG/AT ratios of the sample could be obtained. These MLR results were used to calculate methylation levels of the target genes. For protocol verification, three sets of seven reference DNA solutions with known methylation levels (0%, 1%, 5%, 25%, 50%, 75%, and 100%) were analysed. Clinically, blood plasma samples were taken from 48 non-small-cell lung cancer (NSCLC) patients and 51 healthy controls. The methylation levels of the genes p16, MGMT, and RASSF1 were determined for each patient using this method. Results: Verification experiment on the mixtures with known methylation levels resulted in an error of less than 6% from the actual levels. When applied to our clinical samples, the frequency of methylation in at least one of the three target genes among the NSCLC patients was 87.5%, but this percentage decreased to 11.8% for the control group. The methylation levels of p16 were found to be significantly higher in NSCLC patients with more pack-years smoked (p=0.04), later cancer stages (p=0.03), and cancer types of squamous cell and large cell versus adenocarcinoma (p=0.03). Prediction accuracy of 88% was achieved from classification and regression trees (CART) based on methylation levels and states, respectively. Conclusion: This research showed that the PCR-SERS protocol could quantitatively measure the methylation levels of genes in plasma. The methylation levels of the genes p16, MGMT, and RASSF1 were higher in NSCLC patients than in controls.


Assuntos
Biomarcadores Tumorais/genética , Carcinoma Pulmonar de Células não Pequenas/genética , Metilação de DNA , Neoplasias Pulmonares/genética , Plasma/química , Reação em Cadeia da Polimerase/métodos , Análise Espectral Raman/métodos , Adulto , Idoso , Carcinoma Pulmonar de Células não Pequenas/sangue , Carcinoma Pulmonar de Células não Pequenas/patologia , Estudos de Casos e Controles , Feminino , Voluntários Saudáveis , Humanos , Neoplasias Pulmonares/sangue , Neoplasias Pulmonares/patologia , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Valor Preditivo dos Testes , Regiões Promotoras Genéticas , Fumantes/estatística & dados numéricos
20.
Sensors (Basel) ; 19(23)2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31816939

RESUMO

Nonlinearity and resonance frequency shift make it difficult to control the operation of the traveling-wave ultrasonic motors (TWUSMs) in a wide velocity and load range. In this paper, a velocity control scheme based on the stator vibration amplitude and the parallel resonance frequency (VCBVF) of TWUSMs is proposed. Then, the stator vibration amplitude (SVA) and parallel resonance frequency ( f p ) are detected by a transformer ratio-arm bridge. Based on the linear relationship between the velocity and the SVA of TWUSMs, the proposed scheme achieves the control of the mechanical loop and the electrical loop. The linear relationship between the velocity and the SVA makes the mechanical loop achieve the target velocity efficiently, according to the SVA, and the electrical loop could provide the target SVA quickly. Experimental results show that the response time of velocity is 3-4 ms under different load torques and the overshoot is less than 22%. In addition, the proposed scheme improves the efficiency of TWUSMs due to f p tracking. Due to directing the SVA control, the proposed scheme can heighten the velocity response and the load adaptability of TWUSMs, and promote the application of TWUSMs under various conditions.

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