Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 86
Filtrar
1.
Transl Psychiatry ; 14(1): 168, 2024 Mar 29.
Artículo en Inglés | MEDLINE | ID: mdl-38553454

RESUMEN

Autistic individuals generally demonstrate impaired emotion recognition but it is unclear whether effects are emotion-specific or influenced by oxytocin receptor (OXTR) genotype. Here we implemented a dimensional approach using an implicit emotion recognition task together with functional MRI in a large cohort of neurotypical adult participants (N = 255, male = 131, aged 17-29 years) to establish associations between autistic traits and neural and behavioral responses to specific face emotions, together with modulatory effects of OXTR genotype. A searchlight-based multivariate pattern analysis (MVPA) revealed an extensive network of frontal, basal ganglia, cingulate and limbic regions exhibiting significant predictability for autistic traits from patterns of responses to angry relative to neutral expression faces. Functional connectivity analyses revealed a genotype interaction (OXTR SNPs rs2254298, rs2268491) for coupling between the orbitofrontal cortex and mid-cingulate during angry expression processing, with a negative association between coupling and autistic traits in the risk-allele group and a positive one in the non-risk allele group. Overall, results indicate extensive emotion-specific associations primarily between patterns of neural responses to angry faces and autistic traits in regions processing motivation, reward and salience but not in early visual processing. Functional connections between these identified regions were not only associated with autistic traits but also influenced by OXTR genotype. Thus, altered patterns of neural responses to threatening faces may be a potential biomarker for autistic symptoms although modulatory influences of OXTR genotype need to be taken into account.


Asunto(s)
Trastorno Autístico , Receptores de Oxitocina , Adolescente , Adulto , Femenino , Humanos , Masculino , Adulto Joven , Ira , Trastorno Autístico/genética , Emociones/fisiología , Genotipo , Imagen por Resonancia Magnética , Oxitocina , Receptores de Oxitocina/genética , Receptores de Oxitocina/metabolismo
2.
Environ Res Lett ; 19(3): 034036, 2024 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-38419692

RESUMEN

Road traffic has become the leading source of air pollution in fast-growing sub-Saharan African cities. Yet, there is a dearth of robust city-wide data for understanding space-time variations and inequalities in combustion related emissions and exposures. We combined nitrogen dioxide (NO2) and nitric oxide (NO) measurement data from 134 locations in the Greater Accra Metropolitan Area (GAMA), with geographical, meteorological, and population factors in spatio-temporal mixed effects models to predict NO2 and NO concentrations at fine spatial (50 m) and temporal (weekly) resolution over the entire GAMA. Model performance was evaluated with 10-fold cross-validation (CV), and predictions were summarized as annual and seasonal (dusty [Harmattan] and rainy [non-Harmattan]) mean concentrations. The predictions were used to examine population distributions of, and socioeconomic inequalities in, exposure at the census enumeration area (EA) level. The models explained 88% and 79% of the spatiotemporal variability in NO2 and NO concentrations, respectively. The mean predicted annual, non-Harmattan and Harmattan NO2 levels were 37 (range: 1-189), 28 (range: 1-170) and 50 (range: 1-195) µg m-3, respectively. Unlike NO2, NO concentrations were highest in the non-Harmattan season (41 [range: 31-521] µg m-3). Road traffic was the dominant factor for both pollutants, but NO2 had higher spatial heterogeneity than NO. For both pollutants, the levels were substantially higher in the city core, where the entire population (100%) was exposed to annual NO2 levels exceeding the World Health Organization (WHO) guideline of 10 µg m-3. Significant disparities in NO2 concentrations existed across socioeconomic gradients, with residents in the poorest communities exposed to levels about 15 µg m-3 higher compared with the wealthiest (p < 0.001). The results showed the important role of road traffic emissions in air pollution concentrations in the GAMA, which has major implications for the health of the city's poorest residents. These data could support climate and health impact assessments as well as policy evaluations in the city.

3.
Chem Commun (Camb) ; 60(21): 2926-2929, 2024 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-38372183

RESUMEN

This article introduces a reductive coupling driven by visible-light, facilitating the synthesis of pyridine-substituted alcohols and amines through the reaction of aldehydes, ketones and imines with cyanopyridines. Hantzsch esters serve as reductants in this process, eliminating the need for transition-metals or photosensitizers. The method demonstrates extensive compatibility and finds utility in the late-stage functionalization of both natural and pharmaceutical products, offering a sustainable pathway for the diversification of chemical compounds.

4.
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi ; 40(1): 74-79, 2024 Jan.
Artículo en Chino | MEDLINE | ID: mdl-38246180

RESUMEN

Tumor aerobic glycolysis is one of the main features of tumor metabolic reprogramming. This abnormal glycolytic metabolism provides bioenergy and biomaterials for tumor growth and proliferation. It is worth noting that aerobic glycolysis will not only provide biological materials and energy for tumor cells, but also help tumor cells to escape immune surveillance through regulation of immune microenvironment, thereby resisting tumor immunotherapy and promoting tumor progression. Based on the pathogenesis of renal cell carcinoma, this paper describes the characteristics of aerobic glycolysis, the effect of glycolytic metabolism on the immune microenvironment of renal cell carcinoma, the effect of glycolysis inhibitors on the immune microenvironment of renal cell carcinoma, and the prospect of glycolysis inhibitors combined with immune checkpoint inhibitors in the treatment of renal cell carcinoma.


Asunto(s)
Carcinoma de Células Renales , Neoplasias Renales , Humanos , Carcinoma de Células Renales/terapia , Inmunoterapia , Glucólisis , Reprogramación Metabólica , Neoplasias Renales/terapia , Microambiente Tumoral
5.
Commun Biol ; 7(1): 109, 2024 01 19.
Artículo en Inglés | MEDLINE | ID: mdl-38242969

RESUMEN

Outcomes of past decisions profoundly shape our behavior. However, choice-outcome associations can become volatile and adaption to such changes is of importance. The present study combines pharmaco-electroencephalography with computational modeling to examine whether intranasal oxytocin can modulate reinforcement learning under a volatile vs. a stable association. Results show that oxytocin increases choice accuracy independent of learning context, which is paralleled by a larger N2pc and a smaller P300. Model-based analyses reveal that while oxytocin promotes learning by accelerating value update of outcomes in the volatile context, in the stable context it does so by improving choice consistency. These findings suggest that oxytocin's facilitatory effects on learning may be exerted via improving early attentional selection and late neural processing efficiency, although at the computational level oxytocin's actions are highly adaptive between learning contexts. Our findings provide proof of concept for oxytocin's therapeutic potential in mental disorders with adaptive learning dysfunction.


Asunto(s)
Aprendizaje , Oxitocina , Humanos , Atención , Aprendizaje/fisiología , Trastornos Mentales , Oxitocina/farmacología , Conducta Social
6.
Placenta ; 145: 139-142, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38134546

RESUMEN

Placentae collected from elective terminations during the first trimester are commonly used as control samples in research. However, it is widely acknowledged that many complications of pregnancies can occur or originate during the early stage of gestation. This raises the question that the placentae collected from the first trimester may not accurately reflect normal placental conditions. In this study, 95 placentae were collected from elective terminations and histology was performed. Out of these, 53 placentae (56 %) exhibited the typical structure of placental villi, indicating normal development. However, 42 placentae (44 %) showed placental hydrops, with varying degrees of severity (mild, moderate, or severe). Placental hydrops has been linked to several complicated pregnancies in the later stages of gestation. Our findings suggest that the development of pregnancy pathologies could start in the first trimester, as observed by the presence of hydrops. Placental researchers should be aware of when using first-trimester placentae from termination as controls in studies. However, it remains unclear whether pathological morphologies resolve or ameliorate as the pregnancy progression or whether such placentae continue to have such pathology, but clinical symptoms/signs do not manifest.


Asunto(s)
Enfermedades Placentarias , Placenta , Embarazo , Femenino , Humanos , Primer Trimestre del Embarazo , Vellosidades Coriónicas , Edema
7.
Neuroimage ; 284: 120455, 2023 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-37952779

RESUMEN

Real-time fMRI (rt-fMRI) neurofeedback (NF) training is a novel non-invasive technique for volitional brain modulation. Given the important role of the anterior insula (AI) in human cognitive and affective processes, it has become one of the most investigated regions in rt-fMRI studies. Most rt-fMRI insula studies employed emotional recall/imagery as the regulation strategy, which may be less effective for psychiatric disorders characterized by altered emotional processing. The present study thus aimed to examine the feasibility of a novel interoceptive strategy based on heartbeat detection in rt-fMRI guided AI regulation and its associated behavioral changes using a randomized double-blind, sham feedback-controlled between-subject design. 66 participants were recruited and randomly assigned to receive either NF from the left AI (LAI) or sham feedback from a control region while using the interoceptive strategy. N = 57 participants were included in the final data analyses. Empathic and interoceptive pre-post training changes were collected as behavioral measures of NF training effects. Results showed that participants in the NF group exhibited stronger LAI activity than the control group with LAI activity being positively correlated with interoceptive accuracy following NF training, although there were no significant increases of LAI activity over training sessions. Importantly, ability of LAI regulation could be maintained in a transfer session without feedback. Successful LAI regulation was associated with strengthened functional connectivity of the LAI with cognitive control, memory and learning, and salience/interoceptive networks. The present study demonstrated for the first time the efficacy of a novel regulation strategy based on interoceptive processing in up-regulating LAI activity. Our findings also provide proof of concept for the translational potential of this strategy in rt-fMRI AI regulation of psychiatric disorders characterized by altered emotional processing.


Asunto(s)
Imagen por Resonancia Magnética , Neurorretroalimentación , Humanos , Imagen por Resonancia Magnética/métodos , Neurorretroalimentación/métodos , Emociones/fisiología , Encéfalo/fisiología , Empatía , Mapeo Encefálico/métodos
8.
Waste Manag ; 172: 267-277, 2023 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-37925929

RESUMEN

Dozens of landslide accidents are reported at construction and demolition waste (CDW) landfills worldwide every year. Those accidents could be avoided via timely inspection in which the identification of illegal CDW landfills at a large scale plays a critical role. Traditional field surveys are time-consuming, labor-intensive, which is not effective in large-scale detection of landfills. To address this issue, a methodology is proposed in this study for the automatic identification of CDW landfills in large-scale areas by utilizing semantic segmentation of remote sensing imagery. Deep learning is employed to achieve automatic identification and a case study is conducted to showcase the models. The results shown that: (1) The model proposed in this study can effectively identify CDW landfills, with an accuracy of 96.30 % and an IoU of 74.60 %. (2) DeepLabV3+ demonstrated superior performance over Pspnet and HRNet, though HRNet approached DeepLabV3+ in performance with appropriate optimizations. (3) Case study results indicate the potential existence of 52 CDW landfills in Shenzhen, includng 4 official landfills and 48 suspected illegal CDW landfills, mainly in Longhua, Guangming, and Baoan districts. The method proposed in this study provides an effective approache to identify large-scale illegal CDW landfills and has great significance for supervising CDW landfills.


Asunto(s)
Industria de la Construcción , Administración de Residuos , Industria de la Construcción/métodos , Materiales de Construcción , Reciclaje/métodos , Instalaciones de Eliminación de Residuos , Administración de Residuos/métodos , Residuos Industriales/análisis
9.
Medicine (Baltimore) ; 102(42): e35595, 2023 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-37861515

RESUMEN

Whey-acidic-protein (WAP) four-disulfide core domain protein 3 (WFDC3) is one of the WAP family proteins. This protein family is associated with the development of solid tumors and affects the tumor immunological microenvironment. However, the prognostic value of WFDC3 in pancreatic adenocarcinoma (PAAD) and its effect on the tumor immune microenvironment is yet to be clarified. The Cancer Genome Atlas database and Genotype-Tissue Expression database were used to analyze the differential expression of WFDC3 between the tumor and adjacent tissues. The clinical significance of WFDC3 was analyzed in The Cancer Genome Atlas and International Cancer Genome Consortium database using WFDC3 transcripts and clinical information. In order to elucidate the underlying mechanisms, gene set enrichment analysis was conducted to determine potential activated pathways. Immune score evaluation and publicly available pharmacogenomics database [the Genomics of Drug Sensitivity in Cancer] were utilized to quantify immune cell infiltration and the effect on chemotherapeutic drug sensitivity. WFDC3 levels were higher in PAAD tissues than in normal pancreatic tissues. High levels of WFDC3 expression progressively increased as PAAD tumor stages progressed. Patients with elevated WFDC3 expression showed a poor prognosis. The gene set enrichment analysis analysis revealed that glutamate, arginine, and proline, and histidine metabolism levels were elevated in patients with a high WFDC3 expression phenotype. B, CD4+ T, and CD8+ T cell infiltration was diminished in PAAD tissues with elevated WFDC3 expression. According to pharmacogenomics, PAAD tissues with high WFDC3 expression are susceptible to gemcitabine. WFDC3 is highly expressed in PAAD, and patients with a high level of WFDC3 expression have a shorter overall survival time, indicating a poorer prognosis. High expression of WFDC3 may lead to the development of PAAD by affecting the amino acid metabolism and the tumor immunological microenvironment. WFDC3 may serve as a potential diagnostic and prognostic biomarker for PAAD patients.


Asunto(s)
Adenocarcinoma , Neoplasias Pancreáticas , Humanos , Adenocarcinoma/genética , Neoplasias Pancreáticas/genética , Biología Computacional , Expresión Génica , Pronóstico , Regulación Neoplásica de la Expresión Génica , Microambiente Tumoral/genética , Neoplasias Pancreáticas
10.
Microbiol Spectr ; : e0202623, 2023 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-37707453

RESUMEN

To date, the ectomycorrhizal (EM) fungi community has been widely investigated with aging plantations affected by the pedologic factors. However, knowledge on the effects of phenology induced by climatic factors across the age range remains poorly understood on an intra-annual scale. Here, we sampled the fine roots of Mongolian pine (Pinus sylvestris var. mongolica) plantations at different stages of the growing season (from April to September) across three stand ages (27, 34, and 44 yr) in the Mu Us Desert, Northwest China. We aim to disentangle the community composition and structure of EM fungi, as well as the impact of climate on EM fungi. We observed that the 173 distinct EM fungal operational taxonomic units (OTUs) were identified. Geopora, Inocybe, Tomentella, and Tuber were the most frequent, and their dominance was maintained as stand aging. The richness and community composition were not significantly different with stand aging (P > 0.05). Host phenology and stand age are two important factors that have shaped the EM fungal community. The growing stage affected the beta diversity of the EM fungal community more than stand age, and this variation of the EM fungal community was closely related to seasonal climate, particularly precipitation. This improved information will provide a theoretical basis for the reforestation and rehabilitation of the Mongolian pine plantations using mycorrhizal techniques. IMPORTANCE Ectomycorrhizal (EM) fungi are particularly important for host plants in a desert ecosystem. With a high degree of plasticity, EM fungi are largely influenced by host plant and environmental variables and fundamentally contribute to the ability of individuals to adapt to environmental changes. Therefore, the EM fungi are important for Mongolian pine (Pinus sylvestris var. mongolica) plantation in a desert ecosystem. Although previous studies have concluded that multiple endogenous and exogenous processes ultimately lead to species-specific temporal patterns in EM fungal populations. We still neglect the effect of host phenology on EM fungal activity. The significance of our study is the interplay between climate-driven EM fungi and plant phenology.

11.
Plant Sci ; 335: 111794, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37459955

RESUMEN

Salinity is an important environmental factor in crop growth and development. N6-methyladenosine (m6A) is an essential epigenetic modification that regulates plant-environment interaction. Sugar beet is a major sugar-yielding crop that has a certain tolerance to salt, but the dynamic response elicited by the m6A modification of transcripts under salt stress remains unknown. In this study, sugar beet was exposed to 300 mM NaCl to investigate its physiological response to high salinity and transcriptome-wide m6A modification profile. After the salt treatment, 7737 significantly modified m6A sites and 4981 differentially expressed genes (DEGs) were identified. Among the 312 m6A-modified DEGs, 113 hypomethylated DEGs were up-regulated and 99 hypermethylated DEGs were down-regulated, indicating a negative correlation between m6A modification and gene expression. Well-known salt tolerance genes (e.g., sodium/hydrogen exchanger 1, choline monooxygenase, and nucleoredoxin 2) and phospholipid signaling pathway genes (phosphoinositol-specific phospholipase C, phospholipase D, diacylglycerol kinase 1, etc.) were also among the m6A-modified genes. Further analysis showed that m6A modification may regulate salt-tolerant related gene expression by controlling mRNA stability. Therefore, changes in m6A modification may negatively regulate the expression of the salt-resistant genes in sugar beet, at least in part by modulating the stability of the mRNA via demethylase BvAlkbh10B. These findings could provide a better understanding of the epigenetic mechanisms of salt tolerance in sugar beets and uncover new candidate genes for improving the production of sugar beets planted in high-salinity soil.


Asunto(s)
Beta vulgaris , Tolerancia a la Sal , Tolerancia a la Sal/genética , Beta vulgaris/genética , Regulación de la Expresión Génica de las Plantas , Estrés Salino/genética , Verduras
12.
Comput Med Imaging Graph ; 108: 102249, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-37290374

RESUMEN

Magnetic resonance (MR) and computer tomography (CT) images are two typical types of medical images that provide mutually-complementary information for accurate clinical diagnosis and treatment. However, obtaining both images may be limited due to some considerations such as cost, radiation dose and modality missing. Recently, medical image synthesis has aroused gaining research interest to cope with this limitation. In this paper, we propose a bidirectional learning model, denoted as dual contrast cycleGAN (DC-cycleGAN), to synthesize medical images from unpaired data. Specifically, a dual contrast loss is introduced into the discriminators to indirectly build constraints between real source and synthetic images by taking advantage of samples from the source domain as negative samples and enforce the synthetic images to fall far away from the source domain. In addition, cross-entropy and structural similarity index (SSIM) are integrated into the DC-cycleGAN in order to consider both the luminance and structure of samples when synthesizing images. The experimental results indicate that DC-cycleGAN is able to produce promising results as compared with other cycleGAN-based medical image synthesis methods such as cycleGAN, RegGAN, DualGAN, and NiceGAN. Code is available at https://github.com/JiayuanWang-JW/DC-cycleGAN.


Asunto(s)
Aprendizaje Profundo , Tomografía Computarizada por Rayos X , Tomografía Computarizada por Rayos X/métodos , Procesamiento de Imagen Asistido por Computador/métodos , Computadores , Espectroscopía de Resonancia Magnética
13.
Int J Methods Psychiatr Res ; 32(4): e1970, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37038344

RESUMEN

BACKGROUND: Bipolar disorder's (BD) potential endophenotypes include neurological soft signs (NSS) and neurocognitive disorders (ND). Few research, meanwhile, has coupled NSS and ND as combined endophenotypes of BD. OBJECT: This study intends to investigate NSS and ND and compare their differences in euthymic patients with bipolar disorder (EBP), their unaffected first-degree relatives (FDR), and healthy controls (HC). Additionally, search for potential endophenotypic subprojects of NSS and ND and construct and verify a composite endophenotypic. METHODS: The subjects were all Han Chinese and consisted of 86 EBP, 81 FDR, and 81HC. Cambridge Neurological Inventory and MATRICSTM Consensus Cognitive Battery tested NSS and ND independently. RESULTS: All three groups displayed a trapezoidal distribution of NSS levels and cognitive abnormalities, with EBP having the most severe NSS levels and cognitive deficits, followed by FDR and HC. Among them, motor coordination in NSS and Information processing speed (IPS), Verbal learning (VL), and Working memory (WM) in neurocognitive function are consistent with the traits of the endophenotype of BD. The accuracy in differentiating EBP and HC or FDRs and HC was higher when these items were combined as predictor factors than in differentiating EBP and FDR. CONCLUSION: These results provide more evidence that motor coordination, IPS, VL, and WM may be internal characteristics of bipolar disease. When these characteristics are combined into a complex endophenotype, it may be possible to distinguish BD patients and high-risk groups from normal populations.


Asunto(s)
Trastorno Bipolar , Trastornos del Conocimiento , Disfunción Cognitiva , Humanos , Endofenotipos , Trastorno Bipolar/complicaciones , Trastorno Bipolar/diagnóstico , Pueblos del Este de Asia , Trastornos del Conocimiento/psicología , Disfunción Cognitiva/diagnóstico , Disfunción Cognitiva/etiología , Pruebas Neuropsicológicas
14.
Sci Total Environ ; 875: 162582, 2023 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-36870487

RESUMEN

Growing cities in sub-Saharan Africa (SSA) experience high levels of ambient air pollution. However, sparse long-term city-wide air pollution exposure data limits policy mitigation efforts and assessment of the health and climate effects. In the first study of its kind in West Africa, we developed high resolution spatiotemporal land use regression (LUR) models to map fine particulate matter (PM2.5) and black carbon (BC) concentrations in the Greater Accra Metropolitan Area (GAMA), one of the fastest sprawling metropolises in SSA. We conducted a one-year measurement campaign covering 146 sites and combined these data with geospatial and meteorological predictors to develop separate Harmattan and non-Harmattan season PM2.5 and BC models at 100 m resolution. The final models were selected with a forward stepwise procedure and performance was evaluated with 10-fold cross-validation. Model predictions were overlayed with the most recent census data to estimate the population distribution of exposure and socioeconomic inequalities in exposure at the census enumeration area level. The fixed effects components of the models explained 48-69 % and 63-71 % of the variance in PM2.5 and BC concentrations, respectively. Spatial variables related to road traffic and vegetation explained the most variability in the non-Harmattan models, while temporal variables were dominant in the Harmattan models. The entire GAMA population is exposed to PM2.5 levels above the World Health Organization guideline, including even the Interim Target 3 (15 µg/m3), with the highest exposures in poorer neighborhoods. The models can be used to support air pollution mitigation policies, health, and climate impact assessments. The measurement and modelling approach used in this study can be adapted to other African cities to bridge the air pollution data gap in the region.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Contaminantes Atmosféricos/análisis , Ghana , Monitoreo del Ambiente/métodos , Material Particulado/análisis , Contaminación del Aire/análisis , Hollín/análisis , Carbono/análisis
15.
Opt Lett ; 48(5): 1176-1179, 2023 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-36857242

RESUMEN

Superoscillation refers to a phenomenon where a band-limited wave locally oscillates faster than its highest Fourier component. Current research on optical superoscillations predominantly lies on the basis of free-space waves. As the optical waveguides play a key role in energy and information transportation, guided waves with precisely controlled deep-subwavelength features offers unprecedented flexibility for applications. In this Letter, we numerically show that, by superimposing eigenmodes of a multimode SiO2 waveguide and forcing the resultant field to pass through a set of predetermined points, superoscillatory fields in various shapes can be formed in preset cross-sectional planes. Furthermore, by padding prescribed intensities in multiple cross sections, we successfully create a persistent superoscillatory saddle.

16.
Biomater Transl ; 4(2): 104-114, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38283921

RESUMEN

There is a high demand for bespoke grafts to replace damaged or malformed bone and cartilage tissue. Three-dimensional (3D) printing offers a method of fabricating complex anatomical features of clinically relevant sizes. However, the construction of a scaffold to replicate the complex hierarchical structure of natural tissues remains challenging. This paper reports a novel biofabrication method that is capable of creating intricately designed structures of anatomically relevant dimensions. The beneficial properties of the electrospun fibre meshes can finally be realised in 3D rather than the current promising breakthroughs in two-dimensional (2D). The 3D model was created from commercially available computer-aided design software packages in order to slice the model down into many layers of slices, which were arrayed. These 2D slices with each layer of a defined pattern were laser cut, and then successfully assembled with varying thicknesses of 100 µm or 200 µm. It is demonstrated in this study that this new biofabrication technique can be used to reproduce very complex computer-aided design models into hierarchical constructs with micro and nano resolutions, where the clinically relevant sizes ranging from a simple cube of 20 mm dimension, to a more complex, 50 mm-tall human ears were created. In-vitro cell-contact studies were also carried out to investigate the biocompatibility of this hierarchal structure. The cell viability on a micromachined electrospun polylactic-co-glycolic acid fibre mesh slice, where a range of hole diameters from 200 µm to 500 µm were laser cut in an array where cell confluence values of at least 85% were found at three weeks. Cells were also seeded onto a simpler stacked construct, albeit made with micromachined poly fibre mesh, where cells can be found to migrate through the stack better with collagen as bioadhesives. This new method for biofabricating hierarchical constructs can be further developed for tissue repair applications such as maxillofacial bone injury or nose/ear cartilage replacement in the future.

17.
Biofabrication ; 15(1)2022 12 15.
Artículo en Inglés | MEDLINE | ID: mdl-36541475

RESUMEN

Intervertebral disc (IVD) degeneration is one of the leading causes of disability, and current therapies are mainly unsatisfactory. The key pathological feature during IVD degeneration is the dysfunction of annulus fibrosus (AF). Although tissue-engineered AF has shown great promise for IVD regeneration, the design and fabrication of biomimetic AF scaffold remains a challenge due to the complexity of its structure. Nowadays, 3D printing technology has drawn great attention due to its customizable processes and ability to produce complex tissue architecture. However, few existing 3D printing methods can accurately replicate the fine angle-ply architecture of native AF, which is one of the most critical steps for IVD regeneration, due to the limited printing resolution. In this study, we aimed to fabricate high-resolution polycaprolactone (PCL) scaffolds using a newly developed electrohydrodynamic 3D printing technique. The structural advantages of such scaffolds were verified by finite element analysis (FEA). The PCL scaffolds were further assembled into AF construct to replicate the angle-ply architecture of AF. The optimal assembling method was confirmed by FEA and mechanical tests. Thein vitroexperiments showed that the 3D printed AF scaffolds presented favorable biocompatibility and supported the adhesion and growth of AF cells. Thein vivoperformance of tissue-engineered IVDs (TE-IVDs), which consisted of 3D printed AF scaffold and GelMA hydrogel that simulated nucleus pulposus (NP), were evaluated using a rat total disc replacement model. We found that the implantation of TE-IVDs helped maintain the disc height, reduced the loss of NP water content, and partially restored the biomechanical function of IVD. In addition, the TE-IVDs achieved well integration with adjacent tissues and promoted new tissue formation. In summary, being able to accurately simulate the structural characteristics of native AF, the 3D printed angle-ply AF scaffolds hold potential for future applications in IVD regeneration.


Asunto(s)
Anillo Fibroso , Disco Intervertebral , Ratas , Animales , Andamios del Tejido/química , Ingeniería de Tejidos/métodos , Regeneración , Impresión Tridimensional
18.
Org Lett ; 24(41): 7577-7582, 2022 Oct 21.
Artículo en Inglés | MEDLINE | ID: mdl-36214657

RESUMEN

Here we report a general C(sp3)-H/C(sp3)-H dehydrogenative coupling strategy for the preparation of various natural or unnatural amino acids from readily available glycine derivatives and hydrocarbons through a combination of SET and HAT process.


Asunto(s)
Aminoácidos , Glicina , Glicina/química , Estructura Molecular , Aminas
19.
Am J Cancer Res ; 12(8): 3729-3744, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36119843

RESUMEN

Due to the rapid proliferation, cancer cells have increased anabolic biosynthesis, which requires anaplerosis to replenish precursor intermediates. The major anaplerotic sources are pyruvate and glutamine, which require the catalysis of pyruvate carboxylase (PC) and glutaminase (GLS) respectively. In GLS-suppressed cancer cells, the PC-mediated pathway for anaplerosis is crucial to maintain cell growth and proliferation. Here, we investigated the regulatory role and molecular mechanism of N-myc downstream-regulated gene 2 (NDRG2) in PC and PC-mediated anaplerosis. NDRG2 interacted with PC and induced the degradation of PC in glutamine-deprived cells. NDRG2 also inhibited the activity of PC and PC-mediated anaplerosis. As a result, NDRG2 significantly inhibited the malignant growth and proliferation of glioma cells in combination with a glutamine antagonist. In addition, NDRG2 more significantly inhibited the protein level of PC in isocitrate dehydrogenase 1 (R132H)-mutant glioma cells than in wild-type glioma cells. These findings indicate that the molecular mechanism of NDRG2 inhibits PC-mediated anaplerosis and collaborates with glutamine antagonist to inhibit the malignant proliferation of glioma cells, thus providing a theoretical and experimental basis for targeting anaplerosis in glioma therapy.

20.
J Chem Phys ; 156(24): 244704, 2022 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-35778088

RESUMEN

Plasmonic nanoclusters can strongly absorb light energy and generate hot carriers, which have great potentials in photovoltaic and photocatalytic applications. A vital step for those plasmonic applications is the charge transfer at the metal-semiconductor interface. The effect of the light polarization on the charge transfer has not been theoretically investigated so far. Here, we take the Ag-TiO2 system as a model system to study the polarization effect using time-dependent density functional theory simulations. We find that the charge transfer is sensitive to the light polarization, which has its origin in the polarization-dependent hot carrier distributions. For the linearly polarized light, it shows a sine-square dependence on the polar angle, indicating that the charge transfer response to the linear polarization can be decomposed into components perpendicular and parallel to the interface. We also find that there exists directional charge transfer with a circular light polarization. Our results demonstrate that the light polarization can significantly affect the charge transfer behavior and, thus, offer a new degree of freedom to manipulate the plasmonic applications.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...