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1.
Microb Cell Fact ; 23(1): 76, 2024 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-38461254

RESUMO

BACKGROUND: Aspergillus niger ATCC 20611 is an industrially important fructooligosaccharides (FOS) producer since it produces the ß-fructofuranosidase with superior transglycosylation activity, which is responsible for the conversion of sucrose to FOS accompanied by the by-product (glucose) generation. This study aims to consume glucose to enhance the content of FOS by heterologously expressing glucose oxidase and peroxidase in engineered A. niger. RESULTS: Glucose oxidase was successfully expressed and co-localized with ß-fructofuranosidase in mycelia. These mycelia were applied to synthesis of FOS, which possessed an increased purity of 60.63% from 52.07%. Furthermore, peroxidase was expressed in A. niger and reached 7.70 U/g, which could remove the potential inhibitor of glucose oxidase to facilitate the FOS synthesis. Finally, the glucose oxidase-expressing strain and the peroxidase-expressing strain were jointly used to synthesize FOS, which content achieved 71.00%. CONCLUSIONS: This strategy allows for obtaining high-content FOS by the multiple enzymes expressed in the industrial fungus, avoiding additional purification processes used in the production of oligosaccharides. This study not only facilitated the high-purity FOS synthesis, but also demonstrated the potential of A. niger ATCC 20611 as an enzyme-producing cell factory.


Assuntos
Aspergillus niger , Aspergillus , beta-Frutofuranosidase , Aspergillus niger/genética , Glucose Oxidase/genética , Oligossacarídeos , Peroxidases , Glucose
2.
Rice (N Y) ; 17(1): 18, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38429614

RESUMO

Sulfur (S) is one of the main components of important biomolecules, which has been paid more attention in the anaerobic environment of rice cultivation. In this study, 12 accessions of rice materials, belonging to two Asian rice domestication systems and one African rice domestication system, were used by shotgun metagenomics sequencing to compare the structure and function involved in S cycle of rhizosphere microbiome between wild and cultivated rice. The sulfur cycle functional genes abundances were significantly different between wild and cultivated rice rhizosphere in the processes of sulfate reduction and other sulfur compounds conversion, implicating that wild rice had a stronger mutually-beneficial relationship with rhizosphere microbiome, enhancing sulfur utilization. To assess the effects of sulfate reduction synthetic microbiomes, Comamonadaceae and Rhodospirillaceae, two families containing the genes of two key steps in the dissimilatory sulfate reduction, aprA and dsrA respectively, were isolated from wild rice rhizosphere. Compared with the control group, the dissimilatory sulfate reduction in cultivated rice rhizosphere was significantly improved in the inoculated with different proportions groups. It confirmed that the synthetic microbiome can promote the S-cycling in rice, and suggested that may be feasible to construct the synthetic microbiome step by step based on functional genes to achieve the target functional pathway. In summary, this study reveals the response of rice rhizosphere microbial community structure and function to domestication, and provides a new idea for the construction of synthetic microbiome.

3.
Sci Total Environ ; 924: 171399, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38458464

RESUMO

Soil amendments play a pivotal role in ensuring the safety of food production by inhibiting the transfer of heavy metal ions from soils to crops. Nevertheless, their impact on soil characteristics and the microbial community and their role in reducing cadmium (Cd) accumulation in rice remain unclear. In this study, pot experiments were conducted to investigate the effects of three soil amendments (mineral, organic, and microbial) on the distribution of Cd speciation, organic components, iron oxides, and microbial community structure. The application of soil amendments resulted in significant reductions in the soil available Cd content (16 %-51 %) and brown rice Cd content (16 %-78 %), facilitating the transformation of Cd from unstable forms (decreasing 10 %-20 %) to stable forms (increasing 77 %-150 %) in the soil. The mineral and organic amendments increased the soil cation exchange capacity (CEC) and plant-derived organic carbon (OC), respectively, leading to reduced Cd accumulation in brown rice, while the microbial amendment enhanced OC complexity and the abundances of Firmicutes and Bacteroidota, contributing to the decreased rice Cd uptake. The synchrotron radiation-based Fourier transform infrared (SR-FTIR) spectroscopy indicated that soil amendments regulated soil Cd species by promoting iron oxides and OC coupling. Moreover, both organic and microbial amendments significantly reduced the diversity and richness of the bacterial communities and altered their compositions and structures, by increasing the relative abundances of Bacteroidota and Firmicutes and decreasing those of Acidobacteria, Actinobacteria, and Myxococcota. Soil microbiome analysis revealed that the increase of Firmicutes and Bacteroidota associated with Cd adsorption and sequestration contributed to the suppression of soil Cd reactivity. These findings offer valuable insights into the potential mechanisms by which soil amendments regulate the speciation and bioavailability of Cd, and improve the bacterial communities, thereby providing guidance for agricultural management practices.


Assuntos
Oryza , Poluentes do Solo , Solo/química , Cádmio/análise , Bactérias , Carbono , Oryza/química , Ferro , Minerais , Óxidos , Poluentes do Solo/análise
4.
ACS Appl Mater Interfaces ; 16(10): 12974-12985, 2024 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-38416692

RESUMO

Foot activity can reflect numerous physiological abnormalities in the human body, making gait a valuable metric in health monitoring. Research on flexible sensors for gait monitoring has focused on high sensitivity, wide working range, fast response, and low detection limit, but challenges remain in areas such as elasticity, antibacterial activity, user-friendliness, and long-term stability. In this study, we have developed a novel capacitive pressure sensor that offers an ultralow detection limit of 1 Pa, wide detection ranges from 1 Pa to 2 MPa, a high sensitivity of 0.091 kPa-1, a fast response time of 71 ms, and exceptional stability over 6000 cycles. This sensor not only has the ability of accurately discriminating mechanical stimuli but also meets the requirements of elasticity, antibacterial activity, wearable comfort, and long-term stability for gait monitoring. The fabrication method of a dual dielectric layer and integrated composite electrode is simple, cost-effective, stable, and amenable to mass production. Thereinto, the introduction of a dual dielectric layer, based on an optimized electrospinning network and micropillar array, has significantly improved the sensitivity, detection range, elasticity, and antibacterial performance of the sensor. The integrated flexible electrodes are made by template method using composite materials of carbon nanotubes (CNTs), two-dimensional titanium carbide Ti3C2Tx (MXene), and polydimethylsiloxane (PDMS), offering synergistic advantages in terms of conductivity, stability, sensitivity, and practicality. Additionally, we designed a smart insole that integrates the as-prepared sensors with a miniature instrument as a wearable platform for gait monitoring and disease warning. The developed sensor and wearable platform offer a cutting-edge solution for monitoring human activity and detecting diseases in a noninvasive manner, paving the way for future wearable devices and personalized healthcare technologies.


Assuntos
Nanotubos de Carbono , Humanos , Antibacterianos , Elasticidade , Condutividade Elétrica , Eletrodos
5.
Microorganisms ; 12(2)2024 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-38399698

RESUMO

Soil amendments may enhance crop yield and quality by increasing soil nutrient levels and improving nutrient absorption efficiency, potentially through beneficial microbial interactions. In this work, the effects of amending soil with straw-based carbon substrate (SCS), a novel biochar material, on soil nutrients, soil microbial communities, and maize yield were compared with those of soil amendment with conventional straw. The diversity and abundance of soil bacterial and fungal communities were significantly influenced by both the maize growth period and the treatment used. Regression analysis of microbial community variation indicated that Rhizobiales, Saccharimonadales, and Eurotiales were the bacterial and fungal taxa that exhibited a positive response to SCS amendment during the growth stages of maize. Members of these taxa break down organic matter to release nutrients that promote plant growth and yield. In the seedling and vegetative stages of maize growth, the abundance of Rhizobiales is positively correlated with the total nitrogen (TN) content in the soil. During the tasseling and physiological maturity stages of corn, the abundance of Saccharimonadales and Eurotiales is positively correlated with the content of total carbon (TC), total phosphorus (TP), and available phosphorus (AP) in the soil. The results suggest that specific beneficial microorganisms are recruited at different stages of maize growth to supply the nutrients required at each stage. This targeted recruitment strategy optimizes the availability of nutrients to plants and ultimately leads to higher yields. The identification of these key beneficial microorganisms may provide a theoretical basis for the targeted improvement of crop yield and soil quality. This study demonstrates that SCS amendment enhances soil nutrient content and crop yield compared with conventional straw incorporation and sheds light on the response of soil microorganisms to SCS amendment, providing valuable insights for the future implementation of this material.

6.
Forensic Sci Int ; 355: 111930, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38271828

RESUMO

In forensics, it is important to determine the time since deposition (TSD) of bloodstains, one of the most common types of biological evidence in criminal cases. However, no effective TSD inference methods have been established despite extensive attempts in forensic science. Our study investigated the changes in the blood transcriptome over time, and we found that degradation could be divided into four stages (days 0-2, 4-14, 21-56, and 84-168) at 4 °C. A random forest prediction model based on these transcriptional changes was trained on experimental samples and tested in separate test samples. This model was able to successfully predict TSD (area under the curve [AUC] = 0.995, precision = 1, and recall = 1). Thus, this proof-of-concept pilot study has practical significance for assessing physical evidence. Meanwhile, 11 upregulated and 13 downregulated transcripts were identified as potential time-marker transcripts, laying a foundation for further development of TSD analysis methods in forensic science and crime scene investigation.


Assuntos
Manchas de Sangue , Transcriptoma , Projetos Piloto , Medicina Legal/métodos , Perfilação da Expressão Gênica
7.
ACS Appl Mater Interfaces ; 16(3): 3532-3541, 2024 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-38225868

RESUMO

Triboelectric nanogenerators (TENGs) have attracted a great deal of attention since they can convert ubiquitous mechanical energy into electrical energy and serve as a continuous power source for self-powered sensors. Optimization of the dielectric material composition is an effective way to improve the triboelectric output performance of TENGs. Herein, the hybrid organic-inorganic lead-iodide perovskite Cs0.05FA0.95-xMAxPbI3 was prepared by blade coating and used as a positive friction layer material. Moreover, PVDF-graphene (PG) nanofibers were prepared as negative friction layer materials by electrostatic spinning. The output performance of the TENG was enhanced by varying the MA content of the pervoskite films and the graphene content of the PG nanofibers. The champion output TENG based on Cs0.05FA0.9MA0.05PbI3/PG-0.15 achieved an open-circuit voltage of 245 V, a short-circuit current of 24 µA, and a charge transfer of 80.2 nC. Meanwhile, a maximum power density of 11.23 W m-2 was obtained at 100 MΩ. Moreover, the device exhibits excellent energy-harvesting properties, including excellent stability and durability, rapidly charges capacitors, and lights commercial LEDs and digital tubes.

8.
Analyst ; 149(3): 836-845, 2024 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-38167890

RESUMO

With the vigorous development of biotechnology, genetically modified organisms (GMOs) have become more and more common. In order to effectively supervise and administrate them, the rapid and accurate detection of GMOs is urgently demanded. Here, GMO gene-specific sensing methods based on colorimetry and surface-enhanced Raman scattering (SERS) were proposed based on the lateral branch cleavage function of the CRISPR/Cas12a system. Two transgenes, pCaMV35S and M810 Cry1Ab, were chosen as targets for transgenic crops. By using these methods, we performed transgenic detection on five types of maize leaves and successfully distinguished transgenic from non-transgenic samples. The colorimetric method is rapid, economical and available for field detection. The SERS approach, giving a higher sensitivity to 100 fM, is more suitable for laboratory application scenarios. This study explores practical transgenic detection approaches and will be valuable for the supervision of GMOs.


Assuntos
Sistemas CRISPR-Cas , Zea mays , Plantas Geneticamente Modificadas/genética , Zea mays/genética , Sistemas CRISPR-Cas/genética , Transgenes
9.
J Hazard Mater ; 465: 133101, 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38042006

RESUMO

In view of the near-neutral and high-salt conditions, the Fenton technology with hydroxyl radicals (HO•) as the main reactive species is difficult to satisfy the removal of trace emerging contaminants (ECs) in pharmaceutical sewage. Here, a layered double hydroxide FeZn-LDH was prepared, and the selective formation of ≡Fe(IV)=O in Fenton-like system was accomplished by the chemical environment regulation of the iron sites and the pH control of the microregion. The introduced zinc can increase the length of Fe-O bond in the FeZn-LDH shell layer by 0.22 Å compared to that in Fe2O3, which was conducive to the oxygen transfer process between ≡Fe(III) and H2O2, resulting in the ≡Fe(IV)=O formation. Besides, the amphoteric hydroxide Zn(OH)2 can regulate the pH of the FeZn-LDH surface microregion, maintaining reaction pH at around 6.5-7.5, which could avoid the quenching of ≡Fe(IV)=O by H+. On the other hand, owing to the anti-interference of ≡Fe(IV)=O and the near-zero Zeta potential on the FeZn-LDH surface, the trace ECs can also be effectively degraded under high-salt conditions. Consequently, the process of ≡Fe(IV)=O generation in FeZn-LDH system can satisfy the efficient removal of ECs under near-neutral and high-salt conditions.

10.
Brain Imaging Behav ; 2023 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-38078980

RESUMO

Previous studies have established that the amygdala plays an important role in trait anxiety. However, there remains limited knowledge regarding the changes in amygdala-centered effective connectivity network associated with this trait. The current study employed the Granger Causal analysis to investigate the directional connectivity patterns involving the amygdala in relation to trait anxiety in a large cohort of young adults (N = 424). The results revealed a negative association between trait anxiety scores and the Granger causality from the left middle frontal gyrus and right superior frontal gyrus to the right amygdala. Conversely, higher trait anxiety levels were found to be associated with increased effective connectivity from the left amygdala to the left hippocampus. These results demonstrated the significance of the prefrontal cortex-amygdala-hippocampus neural circuitry in the neurobiological mechanisms underlying trait anxiety. Our findings advance the comprehension of this characteristic, holding promise for informing strategies in the prevention and treatment of related mental disorders.

11.
Neurobiol Stress ; 27: 100584, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37965440

RESUMO

The hippocampus has long been considered a pivotal region implicated in both stress susceptibility and resilience. A wealth of evidence from animal and human studies underscores the significance of hippocampal functional connectivity with the ventromedial prefrontal cortex (vmPFC) in these stress-related processes. However, there remains a scarcity of research that explores and contrasts the roles of hippocampus-vmPFC connectivity in stress susceptibility and resilience when facing a real-life traumatic event from a prospective standpoint. In the present study, we investigated the contributions of undirected and directed connectivity between the hippocampus and vmPFC to stress susceptibility and resilience within the context of the COVID-19 pandemic. Our findings revealed that the left hippocampus-left vmPFC connectivity prior to the pandemic exhibited a negative correlation with both stress susceptibility and resilience. Specifically, individuals with stronger left hippocampus-left vmPFC connectivity reported experiencing fewer stress-related feelings during the outbreak period of the epidemic but displayed lower levels of stress resilience five months later. Our application of spectral dynamic causal modeling unveiled an additional inhibitory connectivity pathway from the left hippocampus to the left vmPFC in the context of stress susceptibility, which was notably absent in stress resilience. Furthermore, we observed a noteworthy positive association between self-inhibition of the vmPFC and stress susceptibility, with this effect proving substantial enough to predict an individual's susceptibility to stress; conversely, these patterns did not manifest in the realm of stress resilience. These findings enrich our comprehension of stress susceptibility and stress resilience and might have implications for innovative approaches to managing stress-related disorders.

12.
Org Biomol Chem ; 21(40): 8054-8074, 2023 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-37801029

RESUMO

Heterocyclic compounds, both naturally derived and synthetically produced, constitute a wide variety of biologically active and industrially important compounds. The synthesis and application of heterocyclic compounds have garnered significant attention and experienced rapid growth in recent decades. Organic azides, due to their unique properties and distinctive reactivity, have become a convenient chemical tool for achieving a wide range of heterocycles such as triazoles and tetrazoles. Importantly, the field of multicomponent reaction (MCR) chemistry provides a convergent approach to access various N-heterocyclic scaffolds, offering novelty, diversity, and complexity. However, the exploration of MCR pathways to N-heterocyclic compounds remains incomplete. Here, we review the use of multicomponent reactions for the preparation of N-heterocycles. A wide range of reactions based on azides for the synthesis of various types of N-heterocyclic systems have been developed.

13.
Sci Total Environ ; 905: 167257, 2023 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-37741415

RESUMO

Nano-scale secondary ion mass spectrometry (NanoSIMS) has emerged as a powerful analytical tool for investigating various aspects of soils. In recent decades, the widespread adoption of advanced instrumentation and methods has contributed significantly to our understanding of organic-mineral assemblages. However, few literature reviews have comprehensively summarized NanoSIMS and its evolution, applications, limitations, and integration with other analytical techniques. In this review, we addressed this gap by comprehensively overviewing the development of NanoSIMS as an analytical tool in soils. This review covers studies on soil organic matter (SOM) cycling, soil-root interactions, and the behavior of metals, discussing the capability and limitations related to the distribution, composition, and interactions of various soil components that occur at mineral-organic interfaces. Furthermore, we examine recent advancements in high-resolution imaging and mass spectrometry technologies and their impact on the utilization of NanoSIMS in soils, along with potential new applications such as utilizing multiple ion beams and integrating them with other analytical techniques. The review emphasizes the importance of employing advanced techniques and methods to explore micro-interfaces and provide in situ descriptions of organic-mineral assemblages in future research. The ongoing development and refinement of NanoSIMS may yield new insights and breakthroughs in soil science, deepening our understanding of the intricate relationships between soil components and the processes that govern soil health and fertility.

14.
Front Psychol ; 14: 1169311, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37583608

RESUMO

Objective: The objective of this study was to explore the mediating effect of adolescent self and courage on the relationship between parenting style in childhood and adult depressed patients' interpersonal relationships in the period of youth. Methods: The study analyzed data from 651 depressed individuals using the Wang Weidong memory-tracing personality developmental inventory (WMPI) from the psychology department of Guang'anmen Hospital. Results: The results of the study show a significant positive correlation between parenting style in childhood, adolescent self, courage, and adult depressed patients' interpersonal relationships in the period of youth. Parenting style in childhood has a direct positive predictive effect on adult depressed patients' interpersonal relationships in the period of youth. It also has an indirect effect on interpersonal relationships in the period of youth through three indirect pathways: the independent mediating effect of adolescent self, the independent mediating effect of adolescent courage, and the chain mediating effect of adolescent self and courage. Conclusion: The findings of this study suggest that parenting style in childhood plays an important role in shaping adult depressed patients' interpersonal relationships in the period of youth. The relationship between parenting style in childhood and interpersonal relationships in the period of youth is influenced by the independent mediating effect of adolescent self and courage, as well as the chain mediating effect of adolescent self and courage. These findings have implications for the development of interventions and programs aimed at improving the mental health and well-being of depressed patients.

15.
Nanomicro Lett ; 15(1): 172, 2023 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-37420119

RESUMO

HIGHLIGHTS: Convincing candidates of flexible (stretchable/compressible) electromagnetic interference shielding nanocomposites are discussed in detail from the views of fabrication, mechanical elasticity and shielding performance. Detailed summary of the relationship between deformation of materials and electromagnetic shielding performance. The future directions and challenges in developing flexible (particularly elastic) shielding nanocomposites are highlighted. With the extensive use of electronic communication technology in integrated circuit systems and wearable devices, electromagnetic interference (EMI) has increased dramatically. The shortcomings of conventional rigid EMI shielding materials include high brittleness, poor comfort, and unsuitability for conforming and deformable applications. Hitherto, flexible (particularly elastic) nanocomposites have attracted enormous interest due to their excellent deformability. However, the current flexible shielding nanocomposites present low mechanical stability and resilience, relatively poor EMI shielding performance, and limited multifunctionality. Herein, the advances in low-dimensional EMI shielding nanomaterials-based elastomers are outlined and a selection of the most remarkable examples is discussed. And the corresponding modification strategies and deformability performance are summarized. Finally, expectations for this quickly increasing sector are discussed, as well as future challenges.

16.
Front Public Health ; 11: 1106499, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37304120

RESUMO

Objective: This study aims to investigate the changes in admission appropriateness after patients were admitted and provide a reference for physicians to make admission decisions and for the supervision of medical service behavior by the medical insurance regulatory department. Methods: Medical records of 4,343 inpatients were obtained based on the largest and most capable public comprehensive hospital in four counties in central and western China for this retrospective study. The binary logistic regression model was employed to examine the determinants of changes in admission appropriateness. Results: Nearly two-in-thirds (65.39%) of the 3,401 inappropriate admissions changed to appropriate at discharge. Age, type of medical insurance, medical service type, severity of the patient upon admission, and disease category were found to be associated with the changes in the appropriateness of admission. Older patients (OR = 3.658, 95% CI [2.462-5.435]; P < 0.001) were more likely to go from "inappropriate" to "appropriate" than younger counterparts. Compared with circulatory diseases, the case evaluated as "appropriate" at discharge was more frequent in the urinary diseases (OR = 1.709, 95% CI [1.019-2.865]; P = 0.042) and genital diseases (OR = 2.998, 95% CI [1.737-5.174]; P < 0.001), whereas the opposite finding was observed for patients with respiratory diseases (OR = 0.347, 95% CI [0.268-0.451]; P < 0.001) and skeletal and muscular diseases (OR = 0.556, 95% CI [0.355-0.873]; P = 0.011). Conclusions: Many disease characteristics gradually emerged after the patient was admitted, thus the appropriateness of admission changed. Physicians and regulators need to take a dynamic view of disease progression and inappropriate admission. Aside from referring to the appropriateness evaluation protocol (AEP), they both should pay attention to individual and disease characteristics to make a comprehensive judgment, and strict control and attention should be paid to the admission of respiratory, skeletal, and muscular diseases.


Assuntos
Hospitalização , Hospitais de Condado , Humanos , Estudos Retrospectivos , Pacientes , China/epidemiologia
17.
Angew Chem Int Ed Engl ; 62(33): e202306229, 2023 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-37338503

RESUMO

Perovskite solar cells (PSCs) are considered as a promising photovoltaic technology due to their high efficiency and low cost. However, their long-term stability, mechanical durability, and environmental risks are still unable to meet practical needs. To overcome these issues, we designed a multifunctional elastomer with abundant hydrogen bonds and carbonyl groups. The chemical bonding between polymer and perovskite could increase the growth activation energy of perovskite film and promote the preferential growth of high-quality perovskite film. Owing to the low defect density and gradient energy-level alignment, the corresponding device exhibited a champion efficiency of 23.10 %. Furthermore, due to the formation of the hydrogen-bonded polymer network in the perovskite film, the target devices demonstrated excellent air stability and enhanced flexibility for the flexible PSCs. More importantly, the polymer network could coordinate with Pb2+ ions, immobilizing lead atoms to reduce their release into the environment. This strategy paves the way for the industrialization of high-performance flexible PSCs.

18.
Micromachines (Basel) ; 14(5)2023 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-37241564

RESUMO

The channel temperature distribution and breakdown points are difficult to monitor for the traditional p-GaN gate HEMTs under high power stress, because the metal gate blocks the light. To solve this problem, we processed p-GaN gate HEMTs with transparent indium tin oxide (ITO) as the gate terminal and successfully captured the information mentioned above, utilizing ultraviolet reflectivity thermal imaging equipment. The fabricated ITO-gated HEMTs exhibited a saturation drain current of 276 mA/mm and an on-resistance of 16.6 Ω·mm. During the test, the heat was found to concentrate in the vicinity of the gate field in the access area, under the stress of VGS = 6 V and VDS = 10/20/30 V. After 691 s high power stress, the device failed, and a hot spot appeared on the p-GaN. After failure, luminescence was observed on the sidewall of the p-GaN while positively biasing the gate, revealing the side wall is the weakest spot under high power stress. The findings of this study provide a powerful tool for reliability analysis and also point to a way for improving the reliability of the p-GaN gate HEMTs in the future.

19.
Micromachines (Basel) ; 14(5)2023 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-37241665

RESUMO

The bias temperature instability (BTI) effect of p-GaN gate high-electron-mobility transistors (HEMTs) is a serious problem for reliability. To uncover the essential cause of this effect, in this paper, we precisely monitored the shifting process of the threshold voltage (VTH) of HEMTs under BTI stress by fast sweeping characterizations. The HEMTs without time-dependent gate breakdown (TDGB) stress featured a high VTH shift of 0.62 V. In contrast, the HEMT that underwent 424 s of TDGB stress clearly saw a limited VTH shift of 0.16 V. The mechanism is that the TDGB stress can induce a Schottky barrier lowering effect on the metal/p-GaN junction, thus boosting the hole injection from the gate metal to the p-GaN layer. This hole injection eventually improves the VTH stability by replenishing the holes lost under BTI stress. It is the first time that we experimentally proved that the BTI effect of p-GaN gate HEMTs was directly dominated by the gate Schottky barrier that impeded the hole supply to the p-GaN layer.

20.
J Transl Med ; 21(1): 356, 2023 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-37248471

RESUMO

BACKGROUND: Circular RNAs (circRNAs) are known to play a crucial role in a variety of malignancies. However, the precise role of circRNAs in cervical squamous cell carcinoma (CSCC) remains largely unknown. METHODS: The expression of circ0001955 was determined by real-time quantitative PCR and fluorescence in situ hybridization. To examine the effects of circ0001955 on CSCC metastasis and growth, functional experiments were conducted in vitro and in vivo. Mechanistically, nucleocytoplasmic separation, dual luciferase reporter assay, RNA antisense purification experiments, and rescue experiments were performed to confirm the interaction between circ0001955, miR-188-3p, and NCAPG2 in CSCC. RESULTS: Here, we demonstrated that a circRNA derived from the CSNK1G1 gene (circ0001955) is significantly upregulated in CSCC. The overexpression of circ0001955 promotes tumor proliferation and metastasis, whereas the knockdown of circ0001955 exerts the opposite effects. Mechanistically, circ0001955 competitively binds miR-188-3p and prevents miR-188-3p from reducing the levels of NCAPG2, activating the AKT/mTOR signaling pathway to induce epithelial mesenchymal transformation. Notably, the application of an inhibitor of mTOR significantly antagonized circ0001955-mediated CSCC tumorigenesis. CONCLUSION: circ0001955 promotes CSCC tumorigenesis and metastasis via the miR-188-3p/NCAPG2 axis which would provide an opportunity to search new therapeutic targets for CSCC.


Assuntos
MicroRNAs , Neoplasias do Colo do Útero , Feminino , Humanos , RNA Circular/genética , MicroRNAs/genética , MicroRNAs/metabolismo , Neoplasias do Colo do Útero/genética , Hibridização in Situ Fluorescente , Carcinogênese/genética , Transformação Celular Neoplásica/genética , Serina-Treonina Quinases TOR/metabolismo , Proliferação de Células/genética , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica , Proteínas Cromossômicas não Histona/metabolismo
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