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1.
Exp Mol Pathol ; 107: 43-50, 2019 04.
Artículo en Inglés | MEDLINE | ID: mdl-30695715

RESUMEN

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. Given the comments of Dr Elisabeth Bik regarding this article "… the Western blot bands in all 400+ papers are all very regularly spaced and have a smooth appearance in the shape of a dumbbell or tadpole, without any of the usual smudges or stains. All bands are placed on similar looking backgrounds, suggesting they were copy/pasted from other sources, or computer generated", the journal requested the authors to provide the raw data. However, the authors were not able to fulfil this request and therefore the Editor-in-Chief decided to retract the article.


Asunto(s)
MicroARNs/metabolismo , Miocarditis/metabolismo , Miocitos Cardíacos/metabolismo , ARN Largo no Codificante/genética , Animales , Línea Celular , Técnicas de Silenciamiento del Gen , Lipopolisacáridos/toxicidad , Mioblastos , Miocitos Cardíacos/patología , Ratas , Regulación hacia Arriba
2.
J Cell Biochem ; 119(12): 9866-9877, 2018 12.
Artículo en Inglés | MEDLINE | ID: mdl-30156009

RESUMEN

Medulloblastoma is a primitive neuroectodermal-derived brain tumor and the most common malignant brain tumor in children. Triptolide (TPL) is the major active component extracted from Tripterygium wilfordii Hook F. This study aimed to explore the effects of TPL on medulloblastoma cell proliferation, migration, and apoptosis, as well as the underlying possible molecular mechanism. Viability, proliferation, and apoptosis of Daoy cells were measured using cell counting kit-8 assay, 5-bromo-2'-deoxyuridine incorporation assay, and Guava Nexin assay, respectively. Cell migration was detected using two-chamber transwell assay and wound healing assay. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was performed to determine the relative expression of microRNA-138 (miR-138) in Daoy cells. Cell transfection was used to change the expression of miR-138 in cells. Western blot analysis was used to analyze the expression of key factors involved in cell apoptosis, cell migration, the phosphatidylinositol 3-kinase (PI3K)/protein kinase 3 (AKT) pathway, and the Notch pathway in Daoy cells. We found that TPL significantly inhibited the viability, proliferation, and migration of Daoy cells but promoted Daoy cell apoptosis. The expression levels of matrix metalloproteinases (MMP)-2 and MMP-9 after TPL treatment were decreased. The expression of miR-138 in Daoy cells after TPL treatment was increased. Suppression of miR-138 obviously reversed the TPL-induced Daoy cell proliferation, migration inhibition, and cell apoptosis enhancement, as well as the inactivation of the PI3K/AKT and Notch pathways. Cyclin-dependent kinase 6 (CDK6) was a direct target gene of miR-138, which might be involved in the antitumor effects of TPL on Daoy cells. In conclusion, our study verified that TPL exerted anticancer effects on medulloblastoma cells possibly via upregulating miR-138 and inactivating the PI3K/AKT and Notch pathways.


Asunto(s)
Proliferación Celular , Neoplasias Cerebelosas/tratamiento farmacológico , Diterpenos/farmacología , Meduloblastoma/tratamiento farmacológico , MicroARNs/genética , Fenantrenos/farmacología , Transducción de Señal , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Línea Celular Tumoral , Movimiento Celular , Neoplasias Cerebelosas/genética , Neoplasias Cerebelosas/metabolismo , Neoplasias Cerebelosas/fisiopatología , Diterpenos/uso terapéutico , Compuestos Epoxi/farmacología , Compuestos Epoxi/uso terapéutico , Regulación Neoplásica de la Expresión Génica , Células HEK293 , Humanos , Meduloblastoma/genética , Meduloblastoma/metabolismo , Meduloblastoma/fisiopatología , Fenantrenos/uso terapéutico , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Receptores Notch/metabolismo
4.
J Xray Sci Technol ; 24(2): 207-19, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27002902

RESUMEN

X-ray imaging applications in medical and material sciences are frequently limited by the number of tomographic projections collected. The inversion of the limited projection data is an ill-posed problem and needs regularization. Traditional spatial regularization is not well adapted to the dynamic nature of time-lapse tomography since it discards the redundancy of the temporal information. In this paper, we propose a novel iterative reconstruction algorithm with a nonlocal regularization term to account for time-evolving datasets. The aim of the proposed nonlocal penalty is to collect the maximum relevant information in the spatial and temporal domains. With the proposed sparsity seeking approach in the temporal space, the computational complexity of the classical nonlocal regularizer is substantially reduced (at least by one order of magnitude). The presented reconstruction method can be directly applied to various big data 4D (x, y, z+time) tomographic experiments in many fields. We apply the proposed technique to modelled data and to real dynamic X-ray microtomography (XMT) data of high resolution. Compared to the classical spatio-temporal nonlocal regularization approach, the proposed method delivers reconstructed images of improved resolution and higher contrast while remaining significantly less computationally demanding.


Asunto(s)
Algoritmos , Tomografía Computarizada Cuatridimensional/métodos , Procesamiento de Imagen Asistido por Computador/métodos , Animales , Ratones , Fantasmas de Imagen , Tibia/diagnóstico por imagen
5.
Thromb Res ; 243: 109152, 2024 Sep 13.
Artículo en Inglés | MEDLINE | ID: mdl-39288599

RESUMEN

INTRODUCTION: Sepsis-induced coagulopathy (SIC) is a severe complication of sepsis, characterized by poor prognosis and high mortality. However, the predictors of SIC in pediatric patients have yet to be identified. Our aim was to develop a user-friendly and efficient nomogram for predicting SIC in sepsis patients admitted to the pediatric intensive care unit (PICU). MATERIALS AND METHODS: We screened 948 sepsis patients admitted to the PICU in three hospitals located in Shandong, China. Least absolute shrinkage and selector operation (LASSO) regression was used in the training cohort for variable selection and regularization. The selected variables were utilized to construct a nomogram for predicting the risk of SIC among sepsis patients admitted to the PICU. RESULTS: Overall, SIC was observed in 324 (40.3 %) patients. The morbidity of SIC in sepsis patients is associated with age, fibrinogen, prothrombin time, C-reactive protein, lactate and the pediatric sequential organ failure assessment score. We developed a nomogram for the early identification of SIC in the training cohort (area under the curve [AUC] 0.869, 95 % confidence interval [CI] 0.830-0.907, sensitivity 75.7 %, specificity 84.8 %) and validation cohorts (validation cohort 1: AUC 0.854, 95 % CI 0.805-0.903, sensitivity 72.0 %, specificity 86.9 %; validation cohort 2: AUC 0.853, 95 % CI 0.796-0.910, sensitivity 70.1 %, specificity 87.8 %). The calibration plots of the nomogram demonstrated a high level of concordance in the SIC probabilities between the observed and predicted values. CONCLUSIONS: The novel nomogram showed excellent predictive performance for the morbidity of SIC among sepsis patients admitted to the PICU, potentially assisting healthcare professionals in early identification and intervention for SIC.

6.
J Intensive Care ; 12(1): 8, 2024 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-38378667

RESUMEN

BACKGROUND: Patients with sepsis-associated encephalopathy (SAE) have higher mortality rates and longer ICU stays. Predictors of SAE are yet to be identified. We aimed to establish an effective and simple-to-use nomogram for the individual prediction of SAE in patients with sepsis admitted to pediatric intensive care unit (PICU) in order to prevent early onset of SAE. METHODS: In this retrospective multicenter study, we screened 790 patients with sepsis admitted to the PICU of three hospitals in Shandong, China. Least absolute shrinkage and selection operator regression was used for variable selection and regularization in the training cohort. The selected variables were used to construct a nomogram to predict the risk of SAE in patients with sepsis in the PICU. The nomogram performance was assessed using discrimination and calibration. RESULTS: From January 2017 to May 2022, 613 patients with sepsis from three centers were eligible for inclusion in the final study. The training cohort consisted of 251 patients, and the two independent validation cohorts consisted of 193 and 169 patients. Overall, 237 (38.7%) patients developed SAE. The morbidity of SAE in patients with sepsis is associated with the respiratory rate, blood urea nitrogen, activated partial thromboplastin time, arterial partial pressure of carbon dioxide, and pediatric critical illness score. We generated a nomogram for the early identification of SAE in the training cohort (area under curve [AUC] 0.82, 95% confidence interval [CI] 0.76-0.88, sensitivity 65.6%, specificity 88.8%) and validation cohort (validation cohort 1: AUC 0.80, 95% CI 0.74-0.86, sensitivity 75.0%, specificity 74.3%; validation cohort 2: AUC 0.81, 95% CI 0.73-0.88, sensitivity 69.1%, specificity 83.3%). Calibration plots for the nomogram showed excellent agreement between SAE probabilities of the observed and predicted values. Decision curve analysis indicated that the nomogram conferred a high net clinical benefit. CONCLUSIONS: The novel nomogram and online calculator showed performance in predicting the morbidity of SAE in patients with sepsis admitted to the PICU, thereby potentially assisting clinicians in the early detection and intervention of SAE.

7.
Ultrason Sonochem ; 111: 107070, 2024 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-39288592

RESUMEN

Metal additive manufacturing (AM) is a disruptive technology that provides unprecedented design freedom and manufacturing flexibility for the forming of complex components. Despite its unparalleled advantages over traditional manufacturing methods, the existence of fatal issues still seriously hinders its large-scale industrial application. Against this backdrop, U-FAAM is emerging as a focus, integrating ultrasonic energy into conventional metal AM processes to harness distinctive advantages. This work offers an up-to-date, specialized review of U-FAAM, articulating the integrated modes, mechanisms, pivotal research achievements, and future development trends in a systematic manner. By synthesizing existing research, it highlights future directions in further optimizing process parameters, expanding material applicability, etc., to advance the industrial application and development of U-FAAM technology.

8.
Front Neurol ; 15: 1418405, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39135753

RESUMEN

Background: As one of the serious complications of sepsis in children, sepsis-associated encephalopathy (SAE) is associated with significantly poor prognosis and increased mortality. However, predictors of outcomes for pediatric SAE patients have yet to be identified. The aim of this study was to develop nomograms to predict the 14-day and 90-day mortality of children with SAE, providing early warning to take effective measures to improve prognosis and reduce mortality. Methods: In this multicenter, retrospective study, we screened 291 patients with SAE admitted to the PICU between January 2017 and September 2022 in Shandong Province. A least absolute shrinkage and selector operation (LASSO) method was used to identify the optimal prognostic factors predicting the outcomes in pediatric patients with SAE. Then, multivariable logistic regression analysis was performed based on these variables, and two nomograms were built for visualization. We used the area under the curve (AUC), calibration curves and decision curves to test the accuracy and discrimination of the nomograms in predicting outcomes. Results: There were 129 patients with SAE in the training cohort, and there were 103 and 59 patients in the two independent validation cohorts, respectively. Vasopressor use, procalcitonin (PCT), lactate and pediatric critical illness score (PCIS) were independent predictive factors for 14-day mortality, and vasopressor use, PCT, lactate, PCIS and albumin were independent predictive factors for 90-day mortality. Based on the variables, we generated two nomograms for the early identification of 14-day mortality (AUC 0.853, 95% CI 0.787-0.919, sensitivity 72.4%, specificity 84.5%) and 90-day mortality (AUC 0.857, 95% CI 0.792-0.923, sensitivity 72.3%, specificity 90.6%), respectively. The calibration plots for nomograms showed excellent agreement of mortality probabilities between the observed and predicted values in both training and validation cohorts. Decision curve analyses (DCA) indicated that nomograms conferred high clinical net benefit. Conclusion: The nomograms in this study revealed optimal prognostic factors for the mortality of pediatric patients with SAE, and individualized quantitative risk evaluation by the models would be practical for treatment management.

9.
Artículo en Inglés | MEDLINE | ID: mdl-39263912

RESUMEN

Grain boundary (GB) engineering includes grain size and GB segregation. Grain size has been proven to affect the electrical properties of Mg3(Sb, Bi)2 at low temperatures. However, the formation mechanism of GB segregation and what kind of GB segregation is beneficial to the performance are still unclear. Here, the Ga/Bi cosegregation at GBs and Mg segregation within grains optimize the transport of electrons and phonons simultaneously. Ga/Bi cosegregation promotes the formation of Janus-like structures due to the diverse ordering tendencies of liquid Mg3Sb2 and Mg3Bi2 and the absence of a solid solution of Ga/Bi. The Janus-like structure significantly reduces the room-temperature lattice thermal conductivity by introducing diverse microdefects. Meanwhile, a coherent interface between the nano Mg segregation region and the matrix is formed, which reduces the thermal conductivity without affecting the carrier transport. Furthermore, the band structure calculations show that Ga doping introduces the resonance level, increasing the Seebeck coefficient. Finally, the lattice thermal conductivity reaches ∼0.4 W m-1 K-1, and a high average ZT of 1.21 between 323 and ∼773 K is achieved for Mg3.2Y0.02Ga0.03Sb1.5Bi0.5. This work provides guidance for improving the thermoelectric performance via designing cosegregation.

10.
Ultrason Sonochem ; 103: 106801, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38364485

RESUMEN

Particle engulfment plays a vital role in the application of particulate reinforced metal matrix composites fabricated by ingot metallurgy. During solidification, particles are nevertheless pushed by an advancing front. As a model system, TiB2p/Al composites were used to investigate the particle engulfment facilitated by acoustic cavitation. The implosion of bubbles drives the particles plunging towards the solid/liquid interface, which increases the engulfment probability. The secondary dendrite arms are refined from 271.2 µm to 98.0 µm as a result of the forced movements of TiB2 particles. Owing to the particle engulfment and dendrite refinement, the composite with ultrasound vibration treatment shows a more rapid work-hardening rate and higher strength.

11.
ACS Appl Mater Interfaces ; 15(42): 49370-49378, 2023 Oct 25.
Artículo en Inglés | MEDLINE | ID: mdl-37824824

RESUMEN

Thermoelectric technology can be utilized to directly convert waste heat into electricity, aiming at energy harvesting in an environmentally friendly manner. As a promising p-type thermoelectric material, CuInTe2 possesses a high inherent lattice thermal conductivity, which limits the practical implementation in the field of thermoelectricity. Herein, through the combination of vacuum melting and annealing along with hot-pressure sintering techniques, we demonstrated that CuIn0.95Ag0.05Te2 thermoelectric materials with trace Ag doping can exhibit a notably high Seebeck coefficient of 614 µV/K, arising from the high density-of-states effective mass and reduced carrier concentration. Owing to the diminished lattice thermal conductivity derived from Umklapp scattering induced by point defects and dislocation, stemming from the trace Ag doping at In sites rather than Cu sites, CuIn0.95Ag0.05Te2 exhibited a maximum figure of merit (ZT) of 1.38 at 823 K, an 18% enhancement over pristine CuInTe2, leading to a maximum average ZT of 0.67 across temperatures ranging from 303 to 823 K. In essence, our work underscores the efficacy of doping engineering and point defects in tailoring the thermoelectric performance of CuInTe2-based materials. This study not only contributes to advancing the fundamental understanding of thermoelectric enhancement but also lays out a practical pathway toward the realization of high-performance CuInTe2-based thermoelectric materials.

12.
Mater Horiz ; 10(2): 454-465, 2023 Feb 06.
Artículo en Inglés | MEDLINE | ID: mdl-36606474

RESUMEN

The thermal conductivity of superlattices is strongly reduced as compared to that of the parent materials due to phonon-scattering and thermal boundary resistances at the superlattice period interfaces. Herein, homogenous superlattices consisting of homogenous structural CeδCa1-δTiO3 and CaTi1-δCeδO3 alternate layers were obtained through a variable-valence Ce doping, providing multi-quantum well interfaces between the alternate layers due to Ce-substitution at Ca and Ti sites, respectively. This material comprising these homogenous superlattices displayed a significantly reduced lattice thermal conductivity of 1.82 W m-1 K-1 and a record high zT value of 0.405 at 1031 K in CaTiO3-based thermoelectric materials. This strategy of synthesizing homogeneous superlattices provides a cost advantage over heterogeneous superlattices prepared by the molecular beam epitaxy method and paves a route for preparing bulk superlattices with unique thermoelectric properties rooting in the quantum domain limiting effect.

13.
Polymers (Basel) ; 14(2)2022 Jan 13.
Artículo en Inglés | MEDLINE | ID: mdl-35054715

RESUMEN

Flight feather shafts are outstanding bioinspiration templates due to their unique light weight and their stiff and strong characteristics. As a thin wall of a natural composite beam, the keratinous cortex has evolved anisotropic features to support flight. Here, the anisotropic keratin composition, tensile response, dynamic properties of the cortex, and fracture behaviors of the shafts are clarified. The analysis of Fourier transform infrared (FTIR) spectra indicates that the protein composition of calamus cortex is almost homogeneous. In the middle and distal shafts (rachis), the content of the hydrogen bonds (HBs) and side-chain is the highest within the dorsal cortex and is consistently lower within the lateral wall. The tensile responses, including the properties and dominant damage pattern, are correlated with keratin composition and fiber orientation in the cortex. As for dynamic properties, the storage modulus and damping of the cortex are also anisotropic, corresponding to variation in protein composition and fibrous structure. The fracture behaviors of bent shafts include matrix breakage, fiber dissociation and fiber rupture on compressive dorsal cortex. To clarify, 'real-time' damage behaviors, and an integrated analysis between AE signals and fracture morphologies, are performed, indicating that calamus failure results from a straight buckling crack and final fiber rupture. Moreover, in the dorsal and lateral walls of rachis, the matrix breakage initially occurs, and then the propagation of the crack is restrained by 'ligament-like' fiber bundles and cross fiber, respectively. Subsequently, the further matrix breakage, interface dissociation and induced fiber rupture in the dorsal cortex result in the final failure.

14.
Adv Sci (Weinh) ; 9(36): e2203546, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36316220

RESUMEN

Laser powder bed fusion (LPBF) can produce high-value metallic components for many industries; however, its adoption for safety-critical applications is hampered by the presence of imperfections. The interdependency between imperfections and processing parameters remains unclear. Here, the evolution of porosity and humps during LPBF using X-ray and electron imaging, and a high-fidelity multiphase process simulation, is quantified. The pore and keyhole formation mechanisms are driven by the mixing of high temperatures and high metal vapor concentrations in the keyhole is revealed. The irregular pores are formed via keyhole collapse, pore coalescence, and then pore entrapment by the solidification front. The mixing of the fast-moving vapor plume and molten pool induces a Kelvin-Helmholtz instability at the melt track surface, forming humps. X-ray imaging and a high-fidelity model are used to quantify the pore evolution kinetics, pore size distribution, waviness, surface roughness, and melt volume under single layer conditions. This work provides insights on key criteria that govern the formation of imperfections in LPBF and suggest ways to improve process reliability.

15.
Front Genet ; 13: 825793, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35368679

RESUMEN

Congenital muscular dystrophy with early rigid spine, also known as the rigid spine with muscular dystrophy type 1 (RSMD1), is caused by SEPN1 mutation. We investigated the clinical manifestations, pathological features, and genetic characteristics of 8 Chinese RSMD1 patients in order to improve diagnosis and management of the disease. Eight patients presented with delayed motor development, muscle weakness, hypotonia, and a myopathic face with high palatine arches. All patients could walk independently, though with poor running and jumping, and most had a rigid spine, lordosis, or scoliosis. The symptoms of respiratory involvement were present early, and upper respiratory tract infections and pneumonia often occurred. Five patients had severe pneumonia, pulmonary hypertension, and respiratory failure. Lung function tests showed variable restrictive ventilation dysfunction. Polysomnography suggested hypoxia and hypoventilation. The serum creatine kinase (CK) level was normal or mildly increased. Muscle biopsy indicated chronic myopathic changes and minicores. Muscle magnetic resonance imaging (MRI) showed diffuse fatty infiltration of the gluteus maximus and thigh muscle. SEPN1 gene analysis revealed 16 compound heterozygous variants, 81.3% of which are unreported, including 7 exon 1 variants. Our study expands the spectrum of clinical and genetic findings in RSMD1 to improve diagnosis, management, and standards of care. SEPN1 mutations in exon 1 are common and easily missed, and exon 1 should be carefully analyzed when RSMD1 is suspected, which will provide valuable genetic counseling for the family and useful information for future natural history studies and clinical trials.

16.
ACS Appl Mater Interfaces ; 12(3): 3773-3783, 2020 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-31880427

RESUMEN

Although Sb doping is regarded as the most effective method to regulate the carrier concentration within the optimum range for ZrNiSn-based half-Heusler (HH) alloys, the resulting thermal conductivity remains high. Hence, the aim of this study was to investigate the effect of "diagonal-rule" doping; that is, the Zr site was displaced by Ta, which can simultaneously enhance the electrical conductivity and reduce the lattice thermal conductivity. The solid-solubility limit of Ta in the ZrNiSn matrix was determined to be x = 0.04. The highest ZT, 0.72, was achieved at 923 K for Zr0.98Ta0.02NiSn. In addition, ZTavg increased by 10.2% for Zr0.98Ta0.02NiSn compared with that for ZrNiSn0.99Sb0.01 at 873 K, which was mainly attributed to the reduced lattice thermal conductivity of Zr0.98Ta0.02NiSn. These results suggest that Ta doping is more effective than Sb doping in ZrNiSn-based HH alloys. In addition, the microhardness of Zr1-xTaxNiSn was substantially improved with increasing Ta content and was also much higher than that of other traditional thermoelectric materials.

17.
Materials (Basel) ; 12(22)2019 Nov 08.
Artículo en Inglés | MEDLINE | ID: mdl-31717329

RESUMEN

In this paper, the microstructures and corrosion behaviors of as-cast Mg-5Sn-xGa alloys with varying Ga content (x = 0, 0.5, 1, 2, 3 wt %) were investigated. The results indicated that Ga could not only adequately refine the grain structure of the alloys, but could also improve the corrosion resistance. The microstructures of all alloys exhibited typical dendritic morphology. No Ga-rich secondary phases were detected when 0.5 wt % Ga was added, while only the morphology of Mg2Sn phase was changed. However, when the addition rate of Ga exceeded 0.5 wt %, an Mg5Ga2 intermetallic compound started to form from the interdendritic region. The volume fraction of Mg5Ga2 monotonically increased with the increasing Ga addition level. Although Mg5Ga2 phase was cathode phase, its pitting sensitivity was weaker than Mg2Sn. In addition, the standard potential of Ga (-0.55 V) was lower than that of Sn (-0.14 V), which relieved the driving force of the secondary phases for the micro-galvanic corrosion. An optimized composition of 3 wt % Ga was concluded based on the immersion tests and polarization measurements, which recorded the best corrosion resistance.

18.
Biomed Pharmacother ; 101: 663-669, 2018 05.
Artículo en Inglés | MEDLINE | ID: mdl-29518613

RESUMEN

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor-in-Chief. Given the comments of Dr Elisabeth Bik regarding this article "This paper belongs to a set of over 400 papers (as per February 2020) that share very similar Western blots with tadpole-like shaped bands, the same background pattern, and striking similarities in title structures, paper layout, bar graph design, and - in a subset - flow cytometry panels", the journal requested the authors to provide the raw data. However, the authors were not able to fulfil this request and therefore the Editor-in-Chief decided to retract the article.


Asunto(s)
Apoptosis/fisiología , Regulación hacia Abajo/fisiología , Lipopolisacáridos/toxicidad , MicroARNs/metabolismo , ARN Largo no Codificante/metabolismo , Animales , Apoptosis/efectos de los fármacos , Línea Celular , Regulación hacia Abajo/efectos de los fármacos , Humanos , Inflamación/inducido químicamente , Inflamación/metabolismo , MicroARNs/antagonistas & inhibidores , Ratas
19.
RSC Adv ; 8(54): 30777-30782, 2018 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-35548765

RESUMEN

Due to the contradiction between mechanical properties and electrical conductivity, it is not easy to fabricate materials with both high strength and good wear resistance with favourable electrical conductivity for the application of electrical materials. In addition, strength and wear resistance do not always present a uniform growth trend at the same time. Herein, a novel copper matrix composite reinforced by in situ synthesized ZrB2 microparticles and nano Cu5Zr precipitates is successfully prepared by a casting method and sequential heat treatments. The Cu/dual-scale particulate composite possesses a desired trade-off of strength, electrical conductivity and wear resistance. ZrB2 microparticles form from Zr and B elements in copper melts, and nanoscale Cu5Zr precipitates form in the matrix after solid solution and aging treatments. The ZrB2 microparticles, nano Cu5Zr precipitates, and well-bonded interfaces contribute to a high tensile strength of 591 MPa and superior wear resistance, with a relative electrical conductivity of 83.7% International Annealed Copper Standard.

20.
Materials (Basel) ; 11(10)2018 Oct 19.
Artículo en Inglés | MEDLINE | ID: mdl-30347641

RESUMEN

Ice cream is a complex multi-phase colloidal soft-solid and its three-dimensional microstructure plays a critical role in determining the oral sensory experience or mouthfeel. Using in-line phase contrast synchrotron X-ray tomography, we capture the rapid evolution of the ice cream microstructure during heat shock conditions in situ and operando, on a time scale of minutes. The further evolution of the ice cream microstructure during storage and abuse was captured using ex situ tomography on a time scale of days. The morphology of the ice crystals and unfrozen matrix during these thermal cycles was quantified as an indicator for the texture and oral sensory perception. Our results reveal that the coarsening is due to both Ostwald ripening and physical agglomeration, enhancing our understanding of the microstructural evolution of ice cream during both manufacturing and storage. The microstructural evolution of this complex material was quantified, providing new insights into the behavior of soft-solids and semi-solids, including many foodstuffs, and invaluable data to both inform and validate models of their processing.

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