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BACKGROUND: Metal implants may affect the image quality, iodine concentration (IC), and CT Hounsfield unit (HU) quantification accuracy. PURPOSE: To investigate the quantitative accuracy of IC and HU from dual-layer spectral detector (DLCT) in the presence of metal artifacts. MATERIAL AND METHODS: An experimental cylindrical phantom containing eight iodine inserts and two metal inserts was designed. The phantom underwent scanning at three radiation dose levels and two tube voltage settings. A set of conventional images (CIs), virtual monoenergetic images (VMIs), and iodine concentration maps (ICMs) were generated and measured for all the eight iodine inserts. Quantitative indicators of mean absolute percentage error (MAPE), artifact index (AI), contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR), and standard deviation (SD) on CIs and VMIs were calculated for IC and HU. Subjective score evaluation was also conducted. RESULTS: The MAPEiodine values of all regions of interest across different scanning configurations were all <5%. Almost all APEiodine values were <5%, indicating that metal artifacts had little impact on IC measurements. When the tube voltage was fixed, the SD value of attenuation decreased with the increase of the tube current; this is also true when the tube current was fixed. The middle energy reconstructions seemed to give a good balance between reducing artifacts and improving contrast. CONCLUSION: VMIs from DLCT can reduce metal artifacts, the accuracy of IC quantification is not sensitive to imaging parameters. In summary, metal implants exhibit minimal impact on image quality and IC quantification accuracy in reconstructed images from DLCT.
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As an environmental enrichment, music can positively influence the immune function, while noise has an adverse effect on the physical and mental health of humans and animals. However, whether music-enriched environments mitigate noise-induced acute stress remains unclear. To investigate the anti-inflammatory effects of music on the immune organs of broiler chickens under conditions of early-life acute noise stress, 140 one-day-old white feather broilers (AA) were randomly divided into four groups: control (C), the music stimulation (M) group, the acute noise stimulation (N) group, the acute noise stimulation followed by music (NM) group. At 14 days of age, the N and NM groups received 120â¯dB noise stimulation for 10â¯min for one week. After acute noise stimulation, the NM group and M group were subjected to continuous music stimulation for 14 days (6â¯h per day, 60â¯dB). At 28 days of age, the body temperature of the chicks, the histopathological changes, quantification of ROS-positive density and apoptosis positivity in tissues of spleen, thymus, and bursa of Fabricius (BF) were measured. The results showed that acute noise stimulation led to an increase in the number and area of splenic microsomes and the cortex/medulla ratio of the detected immune organs. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) of immune tissues of broilers in N group were decreased compared to the broilers in C group, while the mRNA levels of malondialdehyde (MDA), TNF-α, IL-1, and IL-1ß increased. In addition, the gene and protein expression levels of IKK, NF-κB, and IFN-γ of three immune organs from broilers in the N group were increased. Compared to the C and N group, chickens from the NM group showed a decrease in the number and area of splenic follicles, an increase in the activities of SOD and GSH-Px, and a decrease in the expression levels of MDA, TNF-α, IL-1, and IL-1ß. Therefore, a music-enriched environment can attenuate oxidative stress induced by acute noise stimulation, inhibiting the activation of the NF-κB signaling pathway and consequently alleviating the inflammatory response in immune organs.
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Música , FN-kappa B , Humanos , Animales , Preescolar , FN-kappa B/genética , FN-kappa B/metabolismo , Pollos/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Estrés Oxidativo , Transducción de Señal , Superóxido Dismutasa/metabolismo , Interleucina-1/metabolismo , Interleucina-1/farmacologíaRESUMEN
Two new 2,3-dicyanopyrazinophenanthrene-based acceptors (A) p-QCN and m-QCN were synthesized to blend with a donor (D) CPTBF for the exciplex formation. The energy levels of p-QCN and m-QCN are modulated by the peripheral substituents 4- and 3-benzonitrile, respectively. Exciplex-forming blends were identified by the observation of the red-shifted emissions from various D : A blends with higher ratios of donor for suppressing the aggregation of acceptor. The two-component relaxation processes observed by time-resolved photoluminescence support the thermally activated delayed fluorescence (TADF) character of the exciplex-forming blends. The device employing CPTBF : p-QCN and (2 : 1) and CPTBF : m-QCN (2 : 1) blend as the emitting layer (EML) gave EQEmax of 1.76 % and 5.12 %, and electroluminescence (EL) λmax of 629â nm and 618â nm, respectively. The device efficiency can be further improved to 4.32 % and 5.57 % with CPTBF : p-QCN and (4 : 1) and CPTBF : m-QCN (4 : 1) as the EML, which is consistent with their improved photoluminescence quantum yields (PLQYs). A new fluorescent emitter BPBBT with photoluminescence (PL) λmax of 726â nm and a high PLQY of 67 % was synthesized and utilized as the dopant of CPTBF : m-QCN (4 : 1) cohost system. The device employing CPTBF : m-QCN (4 : 1): 5â wt.% BPBBT as the EML gave an EQEmax of 5.02 % and EL λmax centered at 735â nm, however, the weak residual exciplex emission remains. By reducing the donor ratio, the exciplex emission can be completely transferred to BPBBT and the corresponding device with CPTBF : m-QCN (2 : 1): 5â wt.% BPBBT as the EML can achieve EL λmax of 743â nm and EQEmax of 4.79 %. This work manifests the high efficiency near infrared (NIR) OLED can be realized by triplet excitons harvesting of exciplex-forming cohost system, followed by the effective energy transfer to an NIR fluorescent dopant.
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The hydroxylated and diacetylated cyclo-l-Trp-l-Leu derivative (-)-protubonine B was isolated from a culture of Aspergillus ustus 3.3904. Genome mining led to the identification of a putative biosynthetic gene cluster coding for a bimodular nonribosomal peptide synthetase, a flavin-dependent monooxygenase, and two acetyltransferases. Heterologous expression of the pbo cluster in Aspergillus nidulans showed that it is responsible for the formation of the isolated metabolite. Gene deletion experiments and structural elucidation of the isolated intermediates confirmed the biosynthetic steps. In vitro experiments with the recombinant protein proved that the flavin-dependent oxygenase is responsible for stereospecific hydroxylation at the indole ring accompanied by pyrrolidine ring formation.
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Aspergillus nidulans , Oxigenasas , Oxigenasas/genética , Hidroxilación , Aspergillus nidulans/genética , Flavinas/genética , Familia de MultigenesRESUMEN
Isoquercitrin is a natural flavonoid quercetin with anti-inflammatory, anti-anaphylactic, antiviral, and anticancer activities. Here, we investigated the effect of isoquercitrin on immunogenic cell death (ICD) of gastric cancer (GC). The effect of isoquercitrin on GC cell lines (AGS and HGC-27) was evaluated using cell counting kit-8 assays, colony formation assays, Annexin V/PI apoptosis detection kit, western blot analysis, JC-1 staining, immunofluorescence assays, and enzyme-linked immunosorbent assay. Isoquercitrin at doses greater than 20 µM had significant inhibitory effects on the survival of GC cell lines, including HGC-27, AGS, MKN-45, and SNU-1. Isoquercitrin treatment decreased GC cell colony formation in a dose-dependent manner and induced apoptosis accompanied by downregulation of BCL-2 and upregulation of BAX, cleaved caspase-3, and caspase-12. In addition, isoquercitrin promoted the disruption of mitochondrial membrane potential in GC cells. The GC cell surface levels of calreticulin (CRT) and extracellular levels of CRT, ATP, and HMGB1 were enhanced by treatment with isoquercitrin. The protein levels of HMGB1, HSP70, and HSP90 were upregulated by isoquercitrin in a dose-dependent manner. Moreover, the endoplasmic reticulum (ER) stress inhibitor 4-phenylbutyrate reversed isoquercitrin-induced ICD in GC cells. Overall, our data suggested that isoquercitrin induces ER stress and ICD in GC cells. Isoquercitrin may be a candidate anticancer drug for the treatment of GC.
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Proteína HMGB1 , Neoplasias Gástricas , Humanos , Neoplasias Gástricas/tratamiento farmacológico , Quercetina/farmacología , Línea Celular Tumoral , Muerte Celular Inmunogénica , Apoptosis , Estrés del Retículo EndoplásmicoRESUMEN
As industrial development increases, electric machine systems are more widely used in industrial production. Rolling bearings play a key role in machine systems and so the prevention of faults in rolling bearings is more important than ever before. Recently, with the development of artificial intelligence, neural networks have been used to monitor the remaining useful life of rolling bearings. However, there are two problems with this technique. First, a network trained by data for a single operating condition (source domain) cannot predict the remaining useful life of bearings under a different operating condition (target domain), such as a different load or speed. Second, a large number of labeled data are needed for network training, but the acquisition of labeled data for different operating conditions is a challenging task. To address these problems, this paper proposes a domain-adaptive adversarial network, in which a transfer learning strategy and maximum mean discrepancy algorithm are used for network optimization, so that remaining useful life can be predicted without labeled data in target domain training. Our results confirm that a model trained by source domain data alone cannot predict the remaining useful life of bearings under different conditions, but the domain-adaptive adversarial network can accurately predict remaining useful life for varying operating conditions. The method proposed also exhibits good performance even if there are noises in the signals.
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Inteligencia Artificial , Aprendizaje , Algoritmos , Electricidad , Aprendizaje AutomáticoRESUMEN
The pulsed eddy current (PEC) inspection is considered a versatile non-destructive evaluation technique, and it is widely used in metal thickness quantifications for structural health monitoring and target recognition. However, for non-ferromagnetic conductors covered with non-uniform thick insulating layers, there are still deficiencies in the current schemes. The main purpose of this study is to find an effective feature, to measure wall thinning under the large lift-off variations, and further expand application of the PEC technology. Therefore, a novel method named the dynamic apparent time constant (D-ATC) is proposed based on the coil-coupling model. It associates the dynamic behavior of the induced eddy current with the geometric dimensions of the non-ferromagnetic metallic component by the time and amplitude features of the D-ATC curve. Numeral calculations and experiments show that the time signature is immune to large lift-off variations.
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Boiling, the most frequent edible way to hotpot seasoning (HS), exerts a significant impact on the aroma of HS. The present study employed, for the first time, a novel switchable system between GC-O-MS and GC×GC-O-MS (SGC/GC×GC-O-MS) to study the aroma compounds of HS and hotpot seasoning boiling liquid (HSBL). A total of 79 aroma compounds and 56 aroma-active compounds were identified. The aroma extract dilution analysis (AEDA) was used to analyze the differences between the key aroma-active components in the HS and HSBL. The results showed that 13 aroma-active components were significantly affected by boiling, such as D-limonene, methional, and linalool. Moreover, a total of 22 key aroma-active components were identified through the odor activity values (OAVs) calculation. Of them, (E)-2-octenal (fatty) and linalool showed a significant difference, suggesting them to be the most critical aroma-active compounds in the HSBL, and HS, respectively. Finally, the correlation between key aroma-active compounds and the sensory properties of HS and HSBL was studied. These results demonstrated that the OAVs of key aroma-active compounds could characterize the real information of samples through bidirectional orthogonal partial least squares (O2PLS). The analysis results were consistent with the sensory evaluation results.
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Condimentos/análisis , Aromatizantes/análisis , Compuestos Orgánicos Volátiles/análisis , Monoterpenos Acíclicos/aislamiento & purificación , Cromatografía de Gases y Espectrometría de Masas , Calor , Análisis MultivarianteRESUMEN
BACKGROUND: There has been little published data on estimates of HBV and/or HCV coinfection in HIV-positive patients in China or an understanding of how this coinfection varies with different factors. Therefore, this study aimed to determine, through a systematic review and meta-analysis, the prevalence of HBV and/or HCV in HIV-positive patients in China and explore variations in prevalence. METHODS: The Medicine, Web of Science, Chinese Web of Knowledge, and Wanfang databases were searched using a search strategy combining key words and related disease-specific subject terms to identify relevant cohort or cross-sectional studies published up to April 2019. Included articles were assessed for quality. Pooled prevalence and 95% confidence intervals (CIs) were calculated according to study region and other specific characteristics. RESULTS: Our searches identified 7843 records, but only 66 studies were included in our meta-analysis. The pooled HBsAg prevalence in HIV-positive patients was 13.7% (95% CI 12.3-15.3%), with variations found in terms of age and geographic region. The meta-HCV prevalence was 24.7% (95% CI 19.3-30.5%), which varied over the study period and age. The pooled HBV-HCV coinfection prevalence was 3.5% (95% CI 2.4-4.8%), with variations found in terms of age and geographic region. CONCLUSION: Given the high burden of HBV and HCV coinfections in HIV-positive patients, the incorporation of comprehensive screening, treatment, prevention, and vaccination programs into general HIV management in China is imperative.
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Infecciones por VIH/epidemiología , Infecciones por VIH/virología , Hepatitis B/epidemiología , Hepatitis C/epidemiología , China/epidemiología , Costo de Enfermedad , Humanos , PrevalenciaRESUMEN
As an electromagnetic field conversion tool in the transient electromagnetic method (TEM), the weak coupling coils reduce the mutual inductance of its transmitter and receiver coils by special structural optimization, so the detection signal can be protruded from the primary field interference generated by the transmitter coil; thus, this kind of coil design can significantly improve the signal-to-noise ratio. However, with the popularity of drag or aerial TEM exploration, the structural stability problem caused by bumps or windage leads to non-negligible primary field leakages, thereby reducing the detection reliability. This paper incorporates the primary field shielding stability as a key indicator of the weak coupling designs and proposes a calibration scheme for this stability assessment, based on which the shielding stability of five typical weak coupling coil designs is quantitatively compared, and the relationship between the primary field density and the shielding stability explored in this study may contribute to the selection and improvement of TEM coils.
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One of the major causes of death in colorectal cancer (CRC) is invasion and metastasis. Better understanding of the molecular mechanism of CRC invasion and metastasis is essential in developing effective cancer therapies. Cooperative effect of CXCR3 and CXCR4 plays a crucial role in regulating CRC invasion. In present study, we discovered that CRC cells expressing higher levels of CXCR3 and CXCR4 were more invasive. Additionally, CXCR3 formed heteromers with CXCR4 and retained CXCR4 on cell surface. CXCR3 knockdown reduced surface CXCR4 expression and partially inhibited CRC cell invasion. On the contrary, CXCR3 overexpression enhanced surface CXCR4 abundance and promoted CRC cell invasion. Further research indicated that CXCR3-A isoform was responsible for increased CXCR4 surface expression and CRC cell invasion. However, CXCR3-A overexpression without CXCR4 expression did not cause CRC cell invasion, which suggested that CXCR3-A indirectly affect cell invasion through regulating CXCR4. Taken together, CXCR3 enhanced CXCR4 function in CRC cell invasion through forming heteromers with CXCR4 on cell surface and prevent CXCR4 internalization. Therefore, targeting CXCR3 could be a promising strategy for clinical treatment of CRC cell invasion and metastasis.
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Neoplasias Colorrectales/genética , Regulación Neoplásica de la Expresión Génica , Neoplasias Pulmonares/genética , Receptores CXCR3/genética , Receptores CXCR4/genética , Animales , Peso Corporal , Línea Celular Tumoral , Movimiento Celular , Proliferación Celular , Clatrina/antagonistas & inhibidores , Clatrina/genética , Clatrina/metabolismo , Neoplasias Colorrectales/metabolismo , Neoplasias Colorrectales/patología , Femenino , Células HCT116 , Humanos , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/secundario , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Invasividad Neoplásica , Unión Proteica , Transporte de Proteínas , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Receptores CXCR3/antagonistas & inhibidores , Receptores CXCR3/metabolismo , Receptores CXCR4/metabolismo , Transducción de Señal , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
The multi-coil sensor consisting of a series of sub-coils provides a reliable way to avoid signal distortion from excitation field. Compared with conventional coil sensors, the multi-coil sensor exhibits more complex signal conversion performance, and the conventional equivalent circuit cannot reveal the possible attenuated oscillation, which seriously degrades the detection reliability. Based on a novel equivalent circuit model, this research investigates the causes of signal oscillation and proposes and validates an effective solution, which contributes to the signal transmission characteristics of multi-coil sensors for engineering applications.
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The tunnel seismic method allows for the detection of the geology in front of a tunnel face for the safety of tunnel construction. Conventional geophones have problems such as a narrow spectral width, low sensitivity, and poor coupling with the tunnel wall. To tackle issues above, we propose a semi-automatic coupling geophone equipped with a piezoelectric sensor with a spectral range of 10-5000 Hz and a sensitivity of 2.8 V/g. After the geophone was manually pushed into the borehole, it automatically coupled with the tunnel wall under the pressure of the springs within the device. A comparative experiment showed that the data spectrum acquired by the semi-automatic coupling geophone was much higher than that of the conventional geophone equipped with the same piezoelectric sensor. The seismic data were processed in combination with forward modeling. The imaging results also show that the data acquired by the semi-automatic coupling geophone were more in line with the actual geological conditions. In addition, the semi-automatic coupling geophone's installation requires a lower amount of time and cost. In summary, the semi-automatic coupling geophone is able to efficiently acquire seismic data with high fidelity, which can provide a reference for tunnel construction safety.
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The objective of this study was to investigate the effect and the mechanism by which curcumin reverses irinotecan-induced chemotherapy resistance in colon cancer. Construction of irinotecan-resistant colon cancer model LoVo/CPT-11R cells was performed by increasing drug concentration. The Cell Counting Kit-8 assay was used to detect inhibition of proliferation; cell morphology was observed by an optical microscope. Quantitative RT-PCR and western blotting were performed to detect molecular marker expressions during epithelial-mesenchymal transition (EMT); drug-resistant cells were treated with curcumin at different concentrations and Cell Counting Kit-8 was reperformed to detect cell proliferation after treatments. Drug-resistant cells were then divided into four groups: control group, irinotecan group, curcumin group, and irinotecan+curcumin group; quantitative RT-PCR and western blotting were performed to detect molecular marker expressions during epithelial-mesenchymal transition. Flow cytometry was used to detect cell apoptosis after grouping, and apoptosis-related protein was detected by western blotting. LoVo/CPT-11R cells could survive in culture medium containing irinotecan at 60 µg/ml and the drug-resistance index was 5.69; the drug-resistant cells had a larger volume than normal cells and were poorly connected to each other. E-cadherin expression was downregulated, whereas vimentin and N-cadherin expressions were upregulated. After curcumin treatment, drug-resistant cell proliferation was significantly inhibited; in the curcumin+irinotecan treatment group, E-cadherin expression was upregulated, whereas vimentin and N-cadherin expressions were downregulated. Curcumin could significantly increase cell apoptosis. EMT is involved in the development of irinotecan resistance and curcumin can reverse this drug resistance through reversion of the EMT process.
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Antineoplásicos/farmacología , Neoplasias del Colon/tratamiento farmacológico , Curcumina/farmacología , Resistencia a Antineoplásicos/efectos de los fármacos , Transición Epitelial-Mesenquimal/efectos de los fármacos , Irinotecán/farmacología , Antineoplásicos/uso terapéutico , Apoptosis/efectos de los fármacos , Cadherinas/metabolismo , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Neoplasias del Colon/metabolismo , Neoplasias del Colon/patología , Curcumina/uso terapéutico , Interacciones Farmacológicas , Transición Epitelial-Mesenquimal/fisiología , Humanos , Irinotecán/uso terapéutico , Vimentina/metabolismoRESUMEN
DNA topoisomerases-mediated DNA damages are generated from exogenous and endogenous effects, which need to be metabolized or repaired to maintain genome stability involving in many of repair enzymes. Tyrosyl-DNA phosphodiesterase 1(TDP1) and tyrosyl-DNA phosphodiesterase 2(TDP2) are two DNA repair enzymes discovered recently. TDP1 and TDP2 have the ability to hydrolyze the tyrosyl-phosphodiester bond of the phenol of tyrosine with 3'- and 5'-DNA end, respectively, which are contained in the metabolites of the damaged DNA mediated by topoisomerase 1 and topoisomerase 2, respectively. The abnormal activation and expression of TDP1 or TDP2 is the important reason for cancer development. Therefore, TDP1 and TDP2 have been regarded as potential targets in cancer therapy. In this review, we discuss the rationales of their potential as targets and development of their inhibitors together with topoisomerase poisons or DNA damaging agents.
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Daño del ADN , Neoplasias/tratamiento farmacológico , Inhibidores de Fosfodiesterasa/farmacología , ADN-Topoisomerasas/metabolismo , Proteínas de Unión al ADN , Humanos , Proteínas Nucleares/metabolismo , Hidrolasas Diéster Fosfóricas/metabolismo , Factores de Transcripción/metabolismoRESUMEN
In the design of oral cone beam CT, cooperation between synergic control of X-ray source, real-time acquisition of flat detector and motion of mechanical structure affects the CT image quality. Based on the full analysis of the flat detector's timing signal characteristics, this research was carried out with microprocessor controller (MCU), complex programmable logic device (CPLD), and light couplings to design and realize synchronous exposure control system. To evaluate whether the design of the synchronous exposure control system in this project could reach the required imaging accuracy, we employed the projected images in the system to analyze its stability, linear consistency, signal to noise ratio and precede the FDK construction.
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Tomografía Computarizada de Haz Cónico , Radiografía Dental , Fantasmas de ImagenRESUMEN
Biologically plausible learning with neuronal dendrites is a promising perspective to improve the spike-driven learning capability by introducing dendritic processing as an additional hyperparameter. Neuromorphic computing is an effective and essential solution towards spike-based machine intelligence and neural learning systems. However, on-line learning capability for neuromorphic models is still an open challenge. In this study a novel neuromorphic architecture with dendritic on-line learning (NADOL) is presented, which is a novel efficient methodology for brain-inspired intelligence on embedded hardware. With the feature of distributed processing using spiking neural network, NADOL can cut down the power consumption and enhance the learning efficiency and convergence speed. A detailed analysis for NADOL is presented, which demonstrates the effects of different conditions on learning capabilities, including neuron number in hidden layer, dendritic segregation parameters, feedback connection, and connection sparseness with various levels of amplification. Piecewise linear approximation approach is used to cut down the computational resource cost. The experimental results demonstrate a remarkable learning capability that surpasses other solutions, with NADOL exhibiting superior performance over the GPU platform in dendritic learning. This study's applicability extends across diverse domains, including the Internet of Things, robotic control, and brain-machine interfaces. Moreover, it signifies a pivotal step in bridging the gap between artificial intelligence and neuroscience through the introduction of an innovative neuromorphic paradigm.
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Inteligencia Artificial , Educación a Distancia , Redes Neurales de la Computación , Computadores , DendritasRESUMEN
Tendon/ligament (T/L) injuries are a worldwide health problem that affects millions of people annually. Due to the characteristics of tendons, the natural rehabilitation of their injuries is a very complex and lengthy process. Surgical treatment of a T/L injury frequently necessitates using autologous or allogeneic grafts or synthetic materials. Nonetheless, these alternatives have limitations in terms of mechanical properties and histocompatibility, and they do not permit the restoration of the original biological function of the tissue, which can negatively impact the patient's quality of life. It is crucial to find biological materials that possess the necessary properties for the successful surgical treatment of tissues and organs. In recent years, the in vitro regeneration of tissues and organs from stem cells has emerged as a promising approach for preparing autologous tissue and organs, and cell culture scaffolds play a critical role in this process. However, the biological traits and serviceability of different materials used for cell culture scaffolds vary significantly, which can impact the properties of the cultured tissues. Therefore, this review aims to analyze the differences in the biological properties and suitability of various materials based on scaffold characteristics such as cell compatibility, degradability, textile technologies, fiber arrangement, pore size, and porosity. This comprehensive analysis provides valuable insights to aid in the selection of appropriate scaffolds for in vitro tissue and organ culture.
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Ingeniería de Tejidos , Andamios del Tejido , Humanos , Calidad de Vida , Ligamentos , TendonesRESUMEN
The hot deformation behavior of titanium matrix composites plays a crucial role in determining the performance of the formed components. Therefore, it is significant to establish an accurate constitutive relationship between material deformation parameters and flow stress. In this study, hot compression experiments were conducted on a (2.5 vol%TiB + 2.5 vol%TiC)/TC4. The experiments were performed under temperatures ranging from 1013.15 to 1133.15 K and strain rates ranging from 0.001 to 0.1 s-1. Based on the stress-strain data obtained from the experiment, the constitutive models were established by using the Arrhenius model and the BP neural network algorithm, respectively. Considering the relationship between strain rate, hot working temperature, and flow stress, a comparative analysis was conducted to evaluate the prediction accuracy of two different constitutive models. The research results indicate that the flow stress of (2.5 vol%TiB + 2.5 vol%TiC)/TC4 increases with decreasing temperature and increasing strain rate, and the stress-strain curve shows obvious work hardening and softening behaviors. Both the Arrhenius model and the BP neural network algorithm are effective in predicting the hot compression flow stress of (2.5 vol%TiB + 2.5 vol%TiC)/TC4, but the average relative error and root mean square error of the BP neural network algorithm are smaller and the correlation coefficient is higher, thus possessing higher accuracy and reliability.
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BACKGROUND: Increasing data indicated that long noncoding RNAs (lncRNAs) were directly or indirectly involved in the occurrence and development of tumors, including hepatocellular carcinoma (HCC). Recent studies had found that the expression of lncRNA HAND2-AS1 was downregulated in HCC tissues, but its role in HCC progression is unclear. Ultrasound targeted microbubble destruction mediated gene transfection is a new method to overexpress genes. AIM: To study the role of ultrasound microbubbles (UTMBs) mediated HAND2-AS1 in the progression of HCC, in order to provide a new reference for the treatment of HCC. METHODS: In vitro, we transfected HAND2-AS1 siRNA into HepG2 cells by UTMBs, and detected cell proliferation, apoptosis, invasion and epithelial-mesenchymal transition (EMT) by cell counting kit-8 assay, flow cytometry, Transwell invasion assay and Western blotting, respectively. In addition, we transfected miR-837-5p mimic into UTMBs treated cells and observed the changes of cell behavior. Next, the UTMBs treated HepG2 cells were transfected together with miR-837-5p mimic and tissue inhibitor of matrix metalloproteinase-2 (TIMP2) overexpression vector, and we detected cell proliferation, apoptosis, invasion and EMT. In vivo, we established a mouse model of subcutaneous transplantation of HepG2 cells and observed the effect of HAND2-AS1 silencing on tumor formation ability. RESULTS: We found that UTMBs carrying HAND2-AS1 restricted cell proliferation, invasion, and EMT, encouraged apoptosis, and HAND2-AS1 silencing eliminated the effect of UTMBs. Additionally, miR-873-5p targets the gene HAND2-AS1, which also targets the 3'UTR of TIMP2. And miR-873-5p mimic counteracted the impact of HAND2-AS1. Further, miR-873-5p mimic solely or in combination with pcDNA-TIMP2 had been transformed into HepG2 cells exposed to UTMBs. We discovered that TIMP2 reversed the effect of miR-873-5p mimic caused by the blocked signalling cascade for matrix metalloproteinase (MMP) 2/MMP9. In vivo results showed that HAND2-AS1 silencing significantly inhibited tumor formation in mice. CONCLUSION: LncRNA HAND2-AS1 promotes TIMP2 expression by targeting miR-873-5p to inhibit HepG2 cell growth and delay HCC progression.