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1.
Nat Mater ; 2024 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-38890486

RESUMO

Heat dissipation is a natural consequence of operating any electronic system. In nearly all computing systems, such heat is usually minimized by design and cooling. Here, we show that the temporal dynamics of internally produced heat in electronic devices can be engineered to both encode information within a single device and process information across multiple devices. In our demonstration, electronic NbOx Mott neurons, integrated on a flexible organic substrate, exhibit 18 biomimetic neuronal behaviours and frequency-based nociception within a single component by exploiting both the thermal dynamics of the Mott transition and the dynamical thermal interactions with the organic substrate. Further, multiple interconnected Mott neurons spatiotemporally communicate purely via heat, which we use for graph optimization by consuming over 106 times less energy when compared with the best digital processors. Thus, exploiting natural thermal processes in computing can lead to functionally dense, energy-efficient and radically novel mixed-physics computing primitives.

2.
BMC Genomics ; 24(1): 139, 2023 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-36944971

RESUMO

BACKGROUND: Non-human primates, such as Rhesus macaques, are a powerful model for studies of the cellular and physiological effects of radiation, development of radiation biodosimetry, and for understanding the impact of radiation on human health. Here, we study the effects of 4 Gy total body irradiation (TBI) at the molecular level out to 28 days and at the cytogenetic level out to 56 days after exposure. We combine the global transcriptomic and proteomic responses in peripheral whole blood to assess the impact of acute TBI exposure at extended times post irradiation. RESULTS: The overall mRNA response in the first week reflects a strong inflammatory reaction, infection response with neutrophil and platelet activation. At 1 week, cell cycle arrest and re-entry processes were enriched among mRNA changes, oncogene-induced senescence and MAPK signaling among the proteome changes. Influenza life cycle and infection pathways initiated earlier in mRNA and are reflected among the proteomic changes during the first week. Transcription factor proteins SRC, TGFß and NFATC2 were immediately induced at 1 day after irradiation with increased transcriptional activity as predicted by mRNA changes persisting up to 1 week. Cell counts revealed a mild / moderate hematopoietic acute radiation syndrome (H-ARS) reaction to irradiation with expected lymphopenia, neutropenia and thrombocytopenia that resolved within 30 days. Measurements of micronuclei per binucleated cell levels in cytokinesis-blocked T-lymphocytes remained high in the range 0.27-0.33 up to 28 days and declined to 0.1 by day 56. CONCLUSIONS: Overall, we show that the TBI 4 Gy dose in NHPs induces many cellular changes that persist up to 1 month after exposure, consistent with damage, death, and repopulation of blood cells.


Assuntos
Transcriptoma , Irradiação Corporal Total , Animais , Macaca mulatta , Proteoma , Proteômica , Multiômica , Células Sanguíneas , Doses de Radiação
3.
Radiat Environ Biophys ; 62(3): 349-356, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37195317

RESUMO

Radiation dose estimations performed by automated counting of micronuclei (MN) have been studied for their utility for triage following large-scale radiological incidents; although speed is essential, it also is essential to estimate radiation doses as accurately as possible for long-term epidemiological follow-up. Our goal in this study was to evaluate and improve the performance of automated MN counting for biodosimetry using the cytokinesis-block micronucleus (CBMN) assay. We measured false detection rates and used them to improve the accuracy of dosimetry. The average false-positive rate for binucleated cells was 1.14%; average false-positive and -negative MN rates were 1.03% and 3.50%, respectively. Detection errors seemed to be correlated with radiation dose. Correction of errors by visual inspection of images used for automated counting, called the semi-automated and manual scoring method, increased accuracy of dose estimation. Our findings suggest that dose assessment of the automated MN scoring system can be improved by subsequent error correction, which could be useful for performing biodosimetry on large numbers of people rapidly, accurately, and efficiently.


Assuntos
Núcleo Celular , Radiometria , Humanos , Relação Dose-Resposta à Radiação , Radiometria/métodos , Testes para Micronúcleos/métodos , Citocinese , Linfócitos
4.
Cytogenet Genome Res ; 161(6-7): 352-361, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34488220

RESUMO

Detonation of an improvised nuclear device highlights the need to understand the risk of mixed radiation exposure as prompt radiation exposure could produce significant neutron and gamma exposures. Although the neutron component may be a relatively small percentage of the total absorbed dose, the large relative biological effectiveness (RBE) can induce larger biological DNA damage and cell killing. The objective of this study was to use a hematopoietically humanized mouse model to measure chromosomal DNA damage in human lymphocytes 24 h after in vivo exposure to neutrons (0.3 Gy) and X rays (1 Gy). The human dicentric and cytokinesis-block micronucleus assays were performed to measure chromosomal aberrations in human lymphocytes in vivo from the blood and spleen, respectively. The mBAND assay based on fluorescent in situ hybridization labeling was used to detect neutron-induced chromosome 1 inversions in the blood lymphocytes of the neutron-irradiated mice. Cytogenetics endpoints, dicentrics and micronuclei showed that there was no significant difference in yields between the 2 irradiation types at the doses tested, indicating that neutron-induced chromosomal DNA damage in vivo was more biologically effective (RBE ∼3.3) compared to X rays. The mBAND assay, which is considered a specific biomarker of high-LET neutron exposure, confirmed the presence of clustered DNA damage in the neutron-irradiated mice but not in the X-irradiated mice, 24 h after exposure.


Assuntos
Citogenética/métodos , Linfócitos/efeitos da radiação , Nêutrons , Raios X , Adulto , Animais , Células Cultivadas , Inversão Cromossômica/efeitos da radiação , Relação Dose-Resposta à Radiação , Feminino , Humanos , Hibridização in Situ Fluorescente/métodos , Linfócitos/citologia , Linfócitos/metabolismo , Masculino , Camundongos Endogâmicos NOD , Camundongos Knockout , Camundongos SCID , Testes para Micronúcleos/métodos , Pessoa de Meia-Idade
5.
Eur Radiol ; 31(11): 8256-8263, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33876297

RESUMO

OBJECTIVES: There are growing concerns regarding radiation exposure in medical workers who perform interventional fluoroscopy procedures. Owing to the nature of certain interventional procedures, workers may be subjected to partial-body radiation exposure that is high enough to cause local damage. We aimed to investigate the level of radiation exposure in interventional radiologists in South Korea by performing cytogenetic biodosimetry, particularly focusing on partial-body exposure. METHODS: Interventional radiologists (n = 52) completed a questionnaire, providing information about their work history and practices. Blood samples were collected and processed for a dicentric chromosome assay. We determined Papworth's U-value to assess the conformity of dicentrics with the Poisson distribution to estimate the partial-body exposures of the radiologists. RESULTS: Radiologists had a higher number of dicentrics than the normal population and industrial radiographers. Indeed, subjects with a U-value of > 1.96, an indicator of heterogeneous exposure, were observed more frequently; 4.67 ± 0.81% of their body was irradiated at an average dose of 4.64 ± 0.67 Gy. Logistic regression analysis revealed that the total duration of all interventional procedures per week was associated with partial-body exposure levels. CONCLUSIONS: Our findings suggest that interventional radiologists had greater chromosomal damages than those in other occupational groups, and their partial-body exposure levels might be high enough to cause local damage. Use of special dosimeters to monitor partial-body exposure, as well as restricting the time and frequency of interventional procedures, could help reduce occupational radiation exposure. KEY POINTS: • Interventional radiologists had a higher number of dicentrics than the normal population and industrial radiographers. • The level of partial-body exposure of interventional radiologists might be high enough to cause occupational local damage such as a skin cancer in fingers. • Restricting the duration and frequency of interventional procedures might be helpful in reducing occupational radiation exposure.


Assuntos
Exposição Ocupacional , Exposição à Radiação , Cromossomos , Fluoroscopia , Humanos , Doses de Radiação , Exposição à Radiação/análise , Radiologistas
6.
Environ Res ; 184: 109325, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32145547

RESUMO

Biomass valorization is emerging as a new trend for the synthesis of materials for various environmental applications. In this connection, a biochar resulting from pyrolysis of rice straw was employed as a catalytic material for the conversion of hemicellulose-derived furan into value-added platform chemicals such as 1,4-butanediol (1,4-BD) and tetrahydrofuran (THF). The biochar was used as catalyst support of bifunctional Ru-Re catalyst. Two different catalysts were prepared: a conventional activated carbon (AC)-supported Ru-Re catalyst (Ru-Re/AC) and a biochar-supported Ru-Re catalyst (Ru-Re/biochar). The Ru-Re/biochar had a different form of Re species from the Ru-Re/AC, resulting in different reducibility. The difference of reducibility between the two was attributed to alkali metal present in the biochar such as potassium. The Ru-Re/biochar had a 17 times lower metal dispersion on the surface than the Ru-Re/AC, ascribed to a lower surface area of the biochar than the AC. Catalytic activities of the catalysts with regard to reaction rate per available surface active site for transforming furan to 1,4-BD and THF were measured. The Ru-Re/AC was 3 times less active than the Ru-Re/biochar. This study not only provides a way to efficiently use biomass both for environmental catalysts and for feedstock of producing value-added platform chemicals, but also shows potential of biochar for the replacement of typical catalysts employed in biorefinery.


Assuntos
Carvão Vegetal , Furanos , Butileno Glicóis , Pirólise
7.
J Radiol Prot ; 40(1): 151-164, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31539897

RESUMO

Industrial radiographers are exposed to relatively higher doses of radiation than other radiation-exposed workers in South Korea. The objective of our study was to investigate the impact of specific occupational conditions on chromosome aberration frequency and evaluate dosimeter-wearing compliance of industrial radiographers in Korea. We studied individual and occupational characteristics of 120 industrial radiographers working in South Korea and evaluated the frequency of dicentrics and translocations in chromosomes to estimate radiation exposure. The association between working conditions and chromosome aberration frequencies was assessed by Poisson regression analysis after adjusting for confounding factors. Legal personal dosimeter-wearing compliance among workers was investigated by correlation analysis between recorded dose and chromosome aberration frequency. Daily average number of radiographic films used in the last six months was associated with dicentrics frequency. Workers performing site radiography showed significantly higher translocation frequency than those working predominantly in shielded enclosures. The correlation between chromosome aberration frequency and recorded dose was higher in workers in the radiography occupation since 2012 (new workers) than other veteran workers. Our study found that site radiography could affect actual radiation exposure to workers. Controlling these working conditions and making an effort to improve personal dosimeter-wearing compliance among veteran workers as well as new workers may be necessary to reduce radiation exposure as much as possible in their workplace.


Assuntos
Aberrações Cromossômicas , Exposição Ocupacional/análise , Dosímetros de Radiação , Exposição à Radiação/análise , Humanos , Indústrias , Doses de Radiação , República da Coreia
8.
Cancer Sci ; 107(9): 1250-5, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27341700

RESUMO

High-linear energy transfer (LET) heavy ions have been increasingly employed as a useful alternative to conventional photon radiotherapy. As recent studies suggested that high LET radiation mainly affects the nonhomologous end-joining (NHEJ) pathway of DNA double strand break (DSB) repair, we further investigated this concept by evaluating the combined effect of an NHEJ inhibitor (NU7441) at a non-toxic concentration and carbon ions. NU7441-treated non-small cell lung cancer (NSCLC) A549 and H1299 cells were irradiated with X-rays and carbon ions (290 MeV/n, 50 keV/µm). Cell survival was measured by clonogenic assay. DNA DSB repair, cell cycle distribution, DNA fragmentation and cellular senescence induction were studied using a flow cytometer. Senescence-associated protein p21 was detected by western blotting. In the present study, 0.3 µM of NU7441, nontoxic to both normal and tumor cells, caused a significant radio-sensitization in tumor cells exposed to X-rays and carbon ions. This concentration did not seem to cause inhibition of DNA DSB repair but induced a significant G2/M arrest, which was particularly emphasized in p53-null H1299 cells treated with NU7441 and carbon ions. In addition, the combined treatment induced more DNA fragmentation and a higher degree of senescence in H1299 cells than in A549 cells, indicating that DNA-PK inhibitor contributes to various modes of cell death in a p53-dependent manner. In summary, NSCLC cells irradiated with carbon ions were radio-sensitized by a low concentration of DNA-PK inhibitor NU7441 through a strong G2/M cell cycle arrest. Our findings may contribute to further effective radiotherapy using heavy ions.


Assuntos
Cromonas/farmacologia , Quebras de DNA de Cadeia Dupla , Reparo do DNA/efeitos dos fármacos , Proteína Quinase Ativada por DNA/antagonistas & inibidores , Morfolinas/farmacologia , Radiossensibilizantes/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Reparo do DNA/efeitos da radiação , Pontos de Checagem da Fase G2 do Ciclo Celular/efeitos dos fármacos , Pontos de Checagem da Fase G2 do Ciclo Celular/efeitos da radiação , Humanos , Transferência Linear de Energia , Neoplasias Pulmonares
9.
Drug Chem Toxicol ; 37(4): 440-7, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24479558

RESUMO

There are many studies of Gd nephrotoxicity and neurotoxicity, whereas research on cyto- and genotoxicity in normal human lymphocytes is scarce. It is important to investigate the effect of extremely low-frequency electromagnetic fields (ELF-EMF) on Gd toxicity, as patients are co-exposed to Gd and ELF-EMF generated by MRI scanners. We investigated the cytotoxicity and genotoixcity of Gd and the possible enhancing effect of ELF-EMF on Gd toxicity in cultured human lymphocytes by performing a micronuclei (MN) assay, trypan blue dye exclusion, single cell gel electrophoresis, and apoptosis analyses using flow cytometry. Isolated lymphocytes were exposed to 0.2-1.2 mM of Gd only or in combination with a 60-Hz ELF-EMF of 0.8-mT field strength. Exposing human lymphocytes to Gd resulted in a concentration- and time-dependent decrease in cell viability and an increase in MN frequency, single strand DNA breakage, apoptotic cell death, and ROS production. ELF-EMF (0.8 mT) exposure also increased cell death, MN frequency, olive tail moment, and apoptosis induced by Gd treatment alone. These results suggest that Gd induces DNA damage and apoptotic cell death in human lymphocytes and that ELF-EMF enhances the cytotoxicity and genotoxicity of Gd.


Assuntos
Dano ao DNA/efeitos dos fármacos , Campos Eletromagnéticos/efeitos adversos , Gadolínio/toxicidade , Linfócitos/efeitos dos fármacos , Adulto , Apoptose/efeitos dos fármacos , Apoptose/efeitos da radiação , Células Cultivadas , Ensaio Cometa , Dano ao DNA/efeitos da radiação , Relação Dose-Resposta a Droga , Feminino , Citometria de Fluxo , Gadolínio/administração & dosagem , Humanos , Linfócitos/patologia , Linfócitos/efeitos da radiação , Testes para Micronúcleos , Testes de Mutagenicidade , Espécies Reativas de Oxigênio/metabolismo , Fatores de Tempo
10.
J Phys Ther Sci ; 26(7): 1079-82, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25140101

RESUMO

[Purpose] This research investigated the relationship between elbow joint angle and elbow flexor and extensor strength and activation, taking into consideration the length-tension tension curve of the muscle. [Subjects] There were 30 research subjects in total, 15 male and 15 female college students from Busan S University who had no functional disabilities that might affect measurement of muscle strength and muscle activation, and none had they experienced any damage in their upper extremities or hands. [Methods] The elbow joint angles were positioned at angles of 56°, 70° and 84°, and then muscle strength and activation were compared. Repeated measures ANOVA was used for statistical analysis, and the paired t-test was used to identify the difference between each angle. We used the SPSS for windows (ver. 21.0) statistical software and a significance level of α=0.05. [Results] The results showed that muscle strength and activation of the biceps was highest when the joint was placed at 56°. On the other hand, for the triceps, the result was highest when the joint angle was placed at 84°. [Conclusion] The tests confirmed that muscle strength and activation were highest at the joint angle at which the muscle was stretched to 20% more than the resting position in concentric contraction.

11.
Micromachines (Basel) ; 15(2)2024 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-38398981

RESUMO

Memristor devices have diverse physical models depending on their structure. In addition, the physical properties of memristors are described using complex differential equations. Therefore, it is necessary to integrate the various models of memristor into an unified physics-based model. In this paper, we propose a physics-informed neural network (PINN)-based compact memristor model. PINNs can solve complex differential equations intuitively and with ease. This methodology is used to conduct memristor physical analysis. The weight and bias extracted from the PINN are implemented in a Verilog-A circuit simulator to predict memristor device characteristics. The accuracy of the proposed model is verified using two memristor devices. The results show that PINNs can be used to extensively integrate memristor device models.

12.
Int J Radiat Biol ; 100(5): 709-714, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38394348

RESUMO

PURPOSE: Networking with other biodosimetry laboratories is necessary to assess the radiation exposure of many individuals in large-scale radiological accidents. The Korea biodosimetry network, K-BioDos, prepared harmonized scoring guidelines for dicentric chromosome assay to obtain homogeneous results within the network and investigated the efficiency of the guidelines. MATERIALS AND METHODS: Three laboratories in K-BioDos harmonized the scoring guidelines for dicentric chromosome assay. The results of scoring dicentric chromosomes using the harmonized scoring guidelines were compared with the laboratories' results using their own methods. Feedback was collected from the scorers following the three intercomparison exercises in 3 consecutive years. RESULTS: K-BioDos members showed comparable capacity to score dicentrics in the three exercises. However, the results of the K-BioDos guidelines showed no significant improvement over those of the scorers' own methods. According to the scorers, our harmonized guidelines led to more rejected metaphases and ultimately decreased the number of scorable metaphases compared with their own methods. Moreover, the scoring time was sometimes longer with the K-BioDos protocol because some scorers were not yet familiar with the guidelines, though most scorers reported that the time decreased or was unchanged. These challenges may cause low adherence to the guidelines. Most scorers expressed willingness to use the guidelines to select scorable metaphases or identify dicentrics for other biodosimetry works, whereas one did not want to use it due to the difference from their calibration curves. CONCLUSIONS: We identified potential resistance to following the harmonized guidelines and received requests for more detailed methods. Our findings suggest that the harmonized criteria should be continually updated, and education and training should be provided for all scorers. These changes could allow members within the biodosimetry network to successfully collaborate and support each other in large-scale radiological accidents.


Assuntos
Aberrações Cromossômicas , República da Coreia , Humanos , Cromossomos Humanos/genética , Cromossomos Humanos/efeitos da radiação
13.
J Nanosci Nanotechnol ; 13(6): 4437-45, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23862518

RESUMO

Gold nanorods (Au NRs) that absorb near-infrared (NIR) light have great potential in the field of nanomedicine. Photothermal therapy (PTT), a very attractive cancer therapy in nanomedicine, combines nanomaterials and light. The aim of this study was to elucidate the molecular mechanism involved in Au NR-mediated cytotoxic, genotoxic, and other biological responses, in the presence or absence of NIR irradiation. Specifically, cell death mode, generation of reactive oxygen species, DNA damage, apoptotic gene expression, and cell morphological changes induced by Au NRs under NIR irradiation were evaluated in cancer cells. In human lung adenocarcinoma epithelial cells (A549 cells), mild necrosis via DNA damage was induced by NIR responsive Au NRs. Unlike in the cancer cells, cell viability of normal human lymphocyte was not affected by the combined treatment of Au NRs and NIR irradiation. This study delineates differential cytotoxic and genotoxic susceptibility of cancer and normal cells during photothermal treatment of Au NRs. In conclusion, our results suggest that the photothermal cyto-/genotoxic activity of Au NRs is an effective method for cancer therapy in human lung cancer cells.


Assuntos
Coloides , Ouro/química , Nanotubos , Sequência de Bases , Testes de Carcinogenicidade , Linhagem Celular , Ensaio Cometa , Dano ao DNA , Primers do DNA , Humanos , Testes de Mutagenicidade , Espécies Reativas de Oxigênio/metabolismo , Reação em Cadeia da Polimerase em Tempo Real
14.
ScientificWorldJournal ; 2013: 153465, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24381510

RESUMO

A reinforced AdaBoost learning algorithm is proposed for object detection with local pattern representations. In implementing AdaBoost learning, the proposed algorithm employs an exponential criterion as a cost function and Newton's method for its optimization. In particular, we introduce an optimal selection of weak classifiers minimizing the cost function and derive the reinforced predictions based on a judicial confidence estimate to determine the classification results. The weak classifier of the proposed method produces real-valued predictions while that of the conventional AdaBoost method produces integer valued predictions of +1 or -1. Hence, in the conventional learning algorithms, the entire sample weights are updated by the same rate. On the contrary, the proposed learning algorithm allows the sample weights to be updated individually depending on the confidence level of each weak classifier prediction, thereby reducing the number of weak classifier iterations for convergence. Experimental classification performance on human face and license plate images confirm that the proposed method requires smaller number of weak classifiers than the conventional learning algorithm, resulting in higher learning and faster classification rates. An object detector implemented based on the proposed learning algorithm yields better performance in field tests in terms of higher detection rate with lower false positives than that of the conventional learning algorithm.


Assuntos
Algoritmos , Identificação Biométrica , Interpretação de Imagem Assistida por Computador/métodos , Inteligência Artificial , Face , Humanos , Aumento da Imagem/métodos , Aprendizagem , Reprodutibilidade dos Testes , Software
15.
Methods Mol Biol ; 2635: 123-134, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37074660

RESUMO

The γ-H2AX assay is a sensitive and reliable method to evaluate radiation-induced DNA double-strand breaks. The conventional γ-H2AX assay detects individual nuclear foci manually, but is labor-intensive and time-consuming, and hence unsuitable for high-throughput screening in cases of large-scale radiation accidents. We have developed a high-throughput γ-H2AX assay using imaging flow cytometry. This method comprises (1) sample preparation from small volumes of blood in the Matrix™ 96-tube format, (2) automated image acquisition of cells stained with immunofluorescence-labeled γ-H2AX using ImageStream®X, and (3) quantification of γ-H2AX levels and batch processing using the Image Data Exploration and Analysis Software (IDEAS®). This enables the rapid analysis of γ-H2AX levels in several thousand of cells from a small volume of blood with accurate and reliable quantitative measurements for γ-H2AX foci and mean fluorescence levels. This high-throughput γ-H2AX assay could be a useful tool not only for radiation biodosimetry in mass casualty events, but also for large-scale molecular epidemiological studies and individualized radiotherapy.


Assuntos
Ensaios de Triagem em Larga Escala , Histonas , Histonas/genética , Citometria de Fluxo/métodos , Núcleo Celular , Quebras de DNA de Cadeia Dupla
16.
Adv Mater ; 35(47): e2304148, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37527440

RESUMO

Gamma-aminobutyric acid (GABA) is a crucial inhibitory neurotransmitter of the central nervous system. It modifies the signal threshold of the nociceptor, allowing it to react to external stimuli in various circumstances. Thus, GABAergic behaviors are critical characteristics of adaptive behavior in life. Here, a threshold-modulative artificial GABAergic nociceptor is reported for the first time at a Pt/Ti/Nb2 O5- x /Al2 O3- y /Pt/Ti (top to bottom) of the double charge trapping structure. The Al2 O3- y layer contains deep defect states that function similarly to the GABA neurotransmitter in modulating the signal threshold. Meanwhile, the Nb2 O5- x layer traps volatile charges and produces nociceptive behaviors. The combined dynamics of the two layers readily offer threshold-modulative GABAergic nociceptive behaviors. Based on these GABAergic behaviors, a method of implementing hot- and cold-sensitive thermoreceptors is demonstrated and shows its potential applications in advanced sensory devices.


Assuntos
Nociceptores , Ácido gama-Aminobutírico , Ácido gama-Aminobutírico/fisiologia , Neurotransmissores , Sistema Nervoso Central
17.
Biosens Bioelectron ; 236: 115443, 2023 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-37276637

RESUMO

Since the heart pumps out the blood through the excitation-contraction coupling, simultaneous monitoring of the electrical and mechanical characteristics is beneficial for comprehensive diagnosis of cardiac disorders. Currently, these characteristics are monitored separately with electrocardiogram (ECG) and medical imaging techniques. This work presents a fully implantable device named mechano-electrocardiogram (MECG) sensor that can measure mechanocardiogram (MCG) and ECG together. The key to the success is fabrication of permeable electrodes on a single low-modulus porous nanofiber mat, which helps immediate adhesion of the sensor on the tissue. A strain-insensitive electrode is used as the ECG electrode and a strain-sensitive electrode is used for MCG. The MECG device is implanted subcutaneously in the skin above the heart of the rat. Through a vasopressor (phenylephrine) injection test, the MECG signals indicate that the MCG amplitude is related with blood pressure and the ECG peak interval is more related with heart rate. These results confirm that the MECG device is clinically meaningful for continuous and comprehensive monitoring of the electrical and mechanical characteristics of the heart.


Assuntos
Técnicas Biossensoriais , Ratos , Animais , Coração , Eletrocardiografia/métodos , Frequência Cardíaca , Próteses e Implantes
18.
Int J Cardiol ; 387: 131133, 2023 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-37355240

RESUMO

OBJECTIVES: Although pericardiectomy is an effective treatment for constrictive pericarditis (CP), clinical outcomes are not always successful. Pericardial calcification is a unique finding in CP, although the amount and localization of calcification can vary. We investigated how the pattern and amount of pericardial calcification affect mid-term postoperative outcomes after pericardiectomy to treat CP. METHODS: All patients of total pericardiectomy in our hospital from 2010 to 2020 were enrolled. Preoperative Computed tomography (CT) scans of 98 consecutive patients were available and analyzed. Medical records were reviewed retrospectively. Cardiovascular events were defined as cardiovascular death or hospitalization associated with a heart failure symptom, and all-cause events were defined as any event that required admission. CT scans were analyzed, and the volume and localization pattern of peri-calcification were determined. Pericardium calcium scores are presented using Agatston scores. RESULTS: Of the 98 patients, 25 (25.5%) were hospitalized with heart failure symptoms after pericardiectomy. The median follow-up duration for all patients was 172 weeks. The group with a cardiovascular event had a lower calcium score than patients without an event. Multivariate Cox proportional analysis showed that high ln(calcium score+1) before pericardiectomy was a dependent predictor of cardiovascular event (hazard ratio, 0.90; p = 0.04) after pericardiectomy. When we set the cut-off value (ln(calcium score+1) = 7.22), there was a significant difference in cardiovascular events in the multivariate Cox proportional analysis (p = 0.04). CONCLUSION: A low burden of pericardial calcification was associated with a high rate of mid-term clinical events after pericardiectomy to treat CP.


Assuntos
Insuficiência Cardíaca , Pericardite Constritiva , Humanos , Pericardite Constritiva/diagnóstico por imagem , Pericardite Constritiva/cirurgia , Pericardiectomia/efeitos adversos , Estudos Retrospectivos , Cálcio , Fatores de Risco , Insuficiência Cardíaca/etiologia
19.
J Extracell Vesicles ; 12(5): e12325, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37140946

RESUMO

People exposed to radiation in cancer therapy and nuclear accidents are at increased risk of cardiovascular outcomes in long-term survivors. Extracellular vesicles (EVs) are involved in radiation-induced endothelial dysfunction, but their role in the early stage of vascular inflammation after radiation exposure remains to be fully understood. Herein, we demonstrate that endothelial cell-derived EVs containing miRNAs initiate monocyte activation in radiation-induced vascular inflammation. In vitro co-culture and in vivo experimental data showed that endothelial EVs can be sensitively increased by radiation exposure in a dose-dependent manner, and stimulate monocytes releasing monocytic EVs and adhesion to endothelial cells together with an increase in the expression of genes encoding specific ligands for cell-cell interaction. Small RNA sequencing and transfection using mimics and inhibitors explained that miR-126-5p and miR-212-3p enriched in endothelial EVs initiate vascular inflammation by monocyte activation after radiation exposure. Moreover, miR-126-5p could be detected in the circulating endothelial EVs of radiation-induced atherosclerosis model mice, which was found to be tightly correlated with the atherogenic index of plasma. In summary, our study showed that miR-126-5p and miR-212-3p present in the endothelial EVs mediate the inflammatory signals to activate monocytes in radiation-induced vascular injury. A better understanding of the circulating endothelial EVs content can promote their use as diagnostic and prognostic biomarkers for atherosclerosis after radiation exposure.


Assuntos
Aterosclerose , Vesículas Extracelulares , MicroRNAs , Animais , Camundongos , Monócitos/metabolismo , Vesículas Extracelulares/metabolismo , Células Endoteliais/metabolismo , MicroRNAs/metabolismo , Aterosclerose/etiologia , Inflamação/metabolismo
20.
Nat Commun ; 14(1): 7199, 2023 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-37938550

RESUMO

Energy-based computing is a promising approach for addressing the rising demand for solving NP-hard problems across diverse domains, including logistics, artificial intelligence, cryptography, and optimization. Probabilistic computing utilizing pbits, which can be manufactured using the semiconductor process and seamlessly integrated with conventional processing units, stands out as an efficient candidate to meet these demands. Here, we propose a novel pbit unit using an NbOx volatile memristor-based oscillator capable of generating probabilistic bits in a self-clocking manner. The noise-induced metal-insulator transition causes the probabilistic behavior, which can be effectively modeled using a multi-noise-induced stochastic process around the metal-insulator transition temperature. We demonstrate a memristive Boltzmann machine based on our proposed pbit and validate its feasibility by solving NP-hard problems. Furthermore, we propose a streamlined operation methodology that considers the autocorrelation of individual bits, enabling energy-efficient and high-performance probabilistic computing.

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