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1.
Brief Bioinform ; 25(3)2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38701420

RESUMO

The relationship between genotype and fitness is fundamental to evolution, but quantitatively mapping genotypes to fitness has remained challenging. We propose the Phenotypic-Embedding theorem (P-E theorem) that bridges genotype-phenotype through an encoder-decoder deep learning framework. Inspired by this, we proposed a more general first principle for correlating genotype-phenotype, and the P-E theorem provides a computable basis for the application of first principle. As an application example of the P-E theorem, we developed the Co-attention based Transformer model to bridge Genotype and Fitness model, a Transformer-based pre-train foundation model with downstream supervised fine-tuning that can accurately simulate the neutral evolution of viruses and predict immune escape mutations. Accordingly, following the calculation path of the P-E theorem, we accurately obtained the basic reproduction number (${R}_0$) of SARS-CoV-2 from first principles, quantitatively linked immune escape to viral fitness and plotted the genotype-fitness landscape. The theoretical system we established provides a general and interpretable method to construct genotype-phenotype landscapes, providing a new paradigm for studying theoretical and computational biology.


Assuntos
COVID-19 , Aprendizado Profundo , Genótipo , Fenótipo , SARS-CoV-2 , SARS-CoV-2/genética , SARS-CoV-2/imunologia , Humanos , COVID-19/virologia , COVID-19/genética , COVID-19/imunologia , Biologia Computacional/métodos , Algoritmos , Aptidão Genética
2.
Med Phys ; 2024 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-38642468

RESUMO

BACKGROUND: Minibeam represents a preclinical spatially fractionated radiotherapy modality with great translational potential. The advantage lies in its high therapeutic index (compared to GRID and LATTICE) and ability to treat at greater depth (compared to microbeam). Proton minibeam radiotherapy (pMBRT) is a synergy of proton and minibeam. While the single-gantry proton facility has gained popularity due to its affordability and compact design, it often has limited beam time available for research purposes. Conversely, given the current requirement of pMBRT on specific minibeam hardware collimators, necessitates a reproducible and fast setup to minimize pMBRT treatment time and streamline the switching time between pMBRT and conventional treatment for clinically translation. PURPOSE: The contribution of this work is the development and characterization of the first pMBRT system tailored for single-gantry proton facility. The system allows for efficient and reproducible plug-and-play setup, achievable within minutes. METHODS: The single room pMBRT system is constructed based on IBA ProteusONE proton machine. The end of nozzle is attached with beam modifying accessories though an accessory drawer. A small snout is attached to the accessory drawer and used to hold apertures and range shifters. The minibeam aperture consists of two components: a fitting ring and an aperture body. Three minibeam apertures were manufactured. The first-generation apertures underwent qualitatively analysis with film, and the second generation aperture underwent more comprehensive quantitative measurement. The reproducibility of the setup is accessed, and the film measurements are performed to characterize the pMBRT system in cross validation with Monte Carlo (MC) simulations. RESULTS: We presented initial results of large field pMBRT aperture and the film measurements indicates the effect of source-to-isocenter distance = 930 cm in Y proton scanning direction. Consistent with TOPAS MC simulation, the dose uniformity of pMBRT field <2 cm is demonstrated to be better than 2%, rendering its suitability for pre-clinical studies. Subsequently, we developed the second generation of aperture with five slits and characterized the aperture with film dosimetry studies and compared the results to the benchmark MC. Comprehensive film measurements were also performed to evaluate the effect of divergence, air gap and gantry-angle dependency and repeatability and revealing a consistent performance within 5%. Furthermore, the 2D gamma analysis indicated a passing rate exceeding 99% using 3% dose difference and 0.2 mm distance agreement criteria. We also establish the peak valley dose ratio and the depth dose profile measurements, and the results are within 10% from MC simulation. CONCLUSIONS: We have developed the first pMBRT system tailored for a single-gantry proton facility, which has demonstrated accuracy in benchmark with MC simulations, and allows for efficient plug-and-play setup, emphasizing efficiency.

3.
ACS Cent Sci ; 10(3): 628-636, 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38559293

RESUMO

Angelica sinensis, commonly known as Dong Quai in Europe and America and as Dang-gui in China, is a medicinal plant widely utilized for the prevention and treatment of osteoporosis. In this study, we report the discovery of a new category of phthalide from Angelica sinensis, namely falcarinphthalides A and B (1 and 2), which contains two fragments, (3R,8S)-falcarindiol (3) and (Z)-ligustilide (4). Falcarinphthalides A and B (1 and 2) represent two unprecedented carbon skeletons of phthalide in natural products, and their antiosteoporotic activities were evaluated. The structures of 1 and 2, including their absolute configurations, were established using extensive analysis of NMR spectra, chemical derivatization, and ECD/VCD calculations. Based on LC-HR-ESI-MS analysis and DFT calculations, a production mechanism for 1 and 2 involving enzyme-catalyzed Diels-Alder/retro-Diels-Alder reactions was proposed. Falcarinphthalide A (1), the most promising lead compound, exhibits potent in vitro antiosteoporotic activity by inhibiting NF-κB and c-Fos signaling-mediated osteoclastogenesis. Moreover, the bioinspired gram-scale total synthesis of 1, guided by intensive DFT study, has paved the way for further biological investigation. The discovery and gram-scale total synthesis of falcarinphthalide A (1) provide a compelling lead compound and a novel molecular scaffold for treating osteoporosis and other metabolic bone diseases.

4.
J Am Chem Soc ; 146(18): 12723-12733, 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38654452

RESUMO

Enfumafungin-type antibiotics, represented by enfumafungin and fuscoatroside, belong to a distinct group of triterpenoids derived from fungi. These compounds exhibit significant antifungal properties with ibrexafungerp, a semisynthetic derivative of enfumafungin, recently gaining FDA's approval as the first oral antifungal drug for treating invasive vulvar candidiasis. Enfumafungin-type antibiotics possess a cleaved E-ring with an oxidized carboxyl group and a reduced methyl group at the break site, suggesting unprecedented C-C bond cleavage chemistry involved in their biosynthesis. Here, we show that a 4-gene (fsoA, fsoD, fsoE, fsoF) biosynthetic gene cluster is sufficient to yield fuscoatroside by heterologous expression in Aspergillus oryzae. Notably, FsoA is an unheard-of terpene cyclase-glycosyltransferase fusion enzyme, affording a triterpene glycoside product that relies on enzymatic fusion. FsoE is a P450 enzyme that catalyzes successive oxidation reactions at C19 to facilitate a C-C bond cleavage, producing an oxidized carboxyl group and a reduced methyl group that have never been observed in known P450 enzymes. Our study thus sets the important foundation for the manufacture of enfumafungin-type antibiotics using biosynthetic approaches.


Assuntos
Antifúngicos , Antifúngicos/química , Antifúngicos/farmacologia , Antifúngicos/metabolismo , Aspergillus oryzae/enzimologia , Aspergillus oryzae/metabolismo , Família Multigênica , Triterpenos/química , Triterpenos/metabolismo , Sistema Enzimático do Citocromo P-450/metabolismo
5.
Phys Med Biol ; 2024 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-38688290

RESUMO

OBJECTIVE: Lowering treatment costs and improving treatment quality are two primary goals for next-generation proton therapy (PT) facilities. This work will design a compact large momentum acceptance superconducting (LMA-SC) gantry beamline to reduce the footprint and expense of the PT facilities, with a novel mixed-size spot scanning method to improve the sparing of organs at risk (OAR). Approach: For the LMA-SC gantry beamline, the movable energy slit is placed in the middle of the last achromatic bending section, and the beam momentum spread of delivered spots can be easily changed during the treatment. Simultaneously, changing the collimator size can provide spots with various lateral spot sizes. Based on the provided large-size and small-size spot models, the treatment planning with mixed spot scanning is optimized: the interior of the target is irradiated with large-size spots (to cover the uniform-dose interior efficiently), while the peripheral of the target is irradiated with small-size spots (to shape the sharp dose falloff at the peripheral accurately). Main results: The treatment plan with mixed-size spot scanning was evaluated and compared with small and large-size spot scanning for thirteen clinical prostate cases. The mixed-size spot plan had superior target dose homogeneities, better protection of OAR, and better plan robustness than the large-size spot plan. Compared to the small-size spot plan, the mixed-size spot plan had comparable plan quality, better plan robustness, and reduced plan delivery time from 65.9 to 40.0 s. Significance: The compact LMA-SC gantry beamline is proposed with mixed-size spot scanning, with demonstrated footprint reduction and improved plan quality compared to the conventional spot scanning method.

6.
Food Chem ; 449: 139191, 2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-38583396

RESUMO

This study discusses interaction differences between three phenols (protocatechuic acid, naringin and tannic acid) and starch helix, investigates influences of phenols at different doses on properties of maize starch, and further determines their effects on quality and function of maize-starchy foods. Simulated results indicate variations of phenolic structure (phenolic hydroxyl group amount, glycoside structure and steric hindrance) and dose induce phenols form different complexes with starch helix. Formation of different starch-phenols complexes alters gelatinization (1.65-5.63 J/g), pasting form, water binding capacity (8.83-12.69 g/g) and particle size distribution of starch. Meanwhile, differences in starch-phenols complexes are reflected in fingerprint area (R1045/1022: 0.920 to 1.047), crystallinity (8.3% to 17.0%), rheology and gel structure of starch. Additionally, phenols change texture and color of cold maize cake, giving them different antioxidant capacity and lower digestibility. Findings are beneficial for understanding interaction between starch and different phenols and their potential application.


Assuntos
Fenóis , Amido , Zea mays , Zea mays/química , Amido/química , Fenóis/química , Qualidade dos Alimentos , Reologia , Antioxidantes/química , Tamanho da Partícula
7.
ACS Nano ; 18(19): 12503-12511, 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38688475

RESUMO

In recent years, liquid metal catalysts have emerged as a compelling choice for the controllable, large-scale, and high-quality synthesis of two-dimensional materials. At present, there is little mechanistic understanding of the intricate catalytic process, though, of its governing factors or what renders it superior to growth at the corresponding solid catalysts. Here, we report on a combined experimental and computational study of the kinetics of graphene growth during chemical vapor deposition on a liquid copper catalyst. By monitoring the growing graphene flakes in real time using in situ radiation-mode optical microscopy, we explore the growth morphology and kinetics over a wide range of CH4-to-H2 pressure ratios and deposition temperatures. Constant growth rates of the flakes' radius indicate a growth mode limited by precursor attachment, whereas methane-flux-dependent flake shapes point to limited precursor availability. Large-scale free energy simulations enabled by an efficient machine-learning moment tensor potential trained to density functional theory data provide quantitative barriers for key atomic-scale growth processes. The wealth of experimental and theoretical data can be consistently combined into a microkinetic model that reveals mixed growth kinetics that, in contrast to the situation at solid Cu, is partly controlled by precursor attachment alongside precursor availability. Key mechanistic aspects that directly point toward the improved graphene quality are a largely suppressed carbon dimer attachment due to the facile incorporation of this precursor species into the liquid surface and a low-barrier ring-opening process that self-heals 5-membered rings resulting from remaining dimer attachments.

8.
Comput Biol Med ; 171: 108218, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38428098

RESUMO

Pulmonary arterial hypertension (PAH) is a rapidly progressive and fatal disease, with right ventricular failure being the primary cause of death in patients with PAH. This study aims to determine the mechanical stimuli that may initiate heart growth and remodelling (G&R). To achieve this, two bi-ventricular models were constructed: one for a control rat heart and another for a rat heart with PAH. The growth of the diseased heart was estimated by warping it to the control heart using an improved large deformation diffeomorphic metric mapping (LDDMM) framework. Correlation analysis was then performed between mechanical cues (stress and strain) and growth tensors, which revealed that principal strains may serve as a triggering stimulus for myocardial growth and remodelling under PAH. The growth tensors, estimated from in vivo images, could explain 84.3% of the observed geometrical changes in the diseased heart with PAH by using a kinematic cardiac growth model. Our approach has the potential to quantify G&R using sparse in vivo images and to provide insights into the underlying mechanism of triggering right heart failure from a biomechanical perspective.


Assuntos
Hipertensão Pulmonar , Hipertensão Arterial Pulmonar , Humanos , Ratos , Animais , Fenômenos Biomecânicos , Coração , Ventrículos do Coração
9.
Front Endocrinol (Lausanne) ; 15: 1359655, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38487344

RESUMO

Objective: There is currently no non-invasive examination that can fully determine the diagnosis of osteomyelitis. SPECT/CT tomographic fusion imaging can provide both local metabolic activity and anatomical information to determine the condition and location. This study evaluates the diagnostic efficacy of 99mTc-MDP SPECT/CT in bone infections, compared to MRI. Methods: In this multicenter retrospective study, 363 patients with suspected bone and joint infections or osteomyelitis were included. Participants underwent 99mTc-MDP SPECT/CT and/or MRI examinations, supplemented by pathogenic bacterial cultures and histopathological analysis. Results: Only SPECT/CT was tested in 169 patients, and only MRI was used in 116. 78 people have implemented both inspections and have detailed information. The diagnostic sensitivity and specificity of SPECT/CT for infection were 96% and 92% respectively, with an accuracy of 96%. For MRI, these figures were 88%, 84%, and 87% respectively. Conclusion: This represents the largest global study to date evaluating osteomyelitis and bone infection diagnosis using 99mTc-MDP SPECT/CT tomographic fusion imaging. The findings indicate that 99mTc-MDP SPECT/CT fusion imaging offers superior diagnostic accuracy compared to MRI. This is particularly evident in cases involving metallic implants and chronic infections. 99mTc-MDP SPECT/CT fusion imaging emerges as a highly suitable non-invasive diagnostic modality, facilitating enhanced clinical follow-up and treatment.


Assuntos
Difosfatos , Osteomielite , Humanos , Estudos Retrospectivos , Medronato de Tecnécio Tc 99m , Tomografia Computadorizada com Tomografia Computadorizada de Emissão de Fóton Único/métodos , Tomografia Computadorizada de Emissão de Fóton Único , Imageamento por Ressonância Magnética , Osteomielite/diagnóstico por imagem
10.
J Nat Prod ; 2024 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-38447084

RESUMO

Oxabornyl polyenes represent a unique group of polyketides characterized by a central polyene core flanked by a conserved oxabornyl moiety and a structurally diverse oxygen heterocyclic ring. They are widely distributed in fungi and possess a variety of biological activities. Due to the significant spatial separation between the two stereogenic ring systems, it is difficult to establish their overall relative configurations. Here, we isolated three oxabornyl polyenes, prugosenes A1-A3 (1-3), from Talaromyces sp. JNU18266-01. Although these compounds were first reported from Penicillium rugulosum, their overall relative and absolute configurations remained unassigned. By employing ozonolysis in combination with ECD calculations, we were able to establish their absolute configurations, and additionally obtained seven new chemical derivatives (4-10). Notably, through NMR data analysis and quantum chemical calculations, we achieved the structural revision of prugosene A2. Furthermore, prugosenes A1-A3 exhibited potent antiviral activity against the respiratory syncytial virus, with compound 1 displaying an IC50 value of 6.3 µM. Our study thus provides a valuable reference for absolute configuration assignment of oxabornyl polyene compounds.

11.
Zootaxa ; 5419(3): 419-429, 2024 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-38480316

RESUMO

The genus Oxyartes currently comprises 17 taxa, of which 12 are found in China, representing the high diversity in China. This list includes the two species from China as described in this paper. The first is a new remarkable species O. bouxraeuz sp. nov. collected from Gulinqing township, Yunnan. The second is a newly recorded species, O. cresphontes. This species is reported from Mdog, Xizang, China. A key to this genus from China is presented. Type specimens are deposited in the Yunnan Agricultural University (YNAU).


Assuntos
Neópteros , Humanos , Animais , China , Universidades
12.
Zootaxa ; 5419(3): 394-400, 2024 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-38480318

RESUMO

Calvisia is a colorful winged stick insect genus consisting of 6 subgenera and 44 species widely distributed in temperate and tropical Asia. C. medogensis syn. nov. was discovered in Mdog, Xizang (Tibet), China and is so far the only species recorded from China. We here propose that C. medogensis syn. nov. is a synonym of C. fuscoalata after checking type specimens of both species. New materials studied are deposited in Yunnan Agricultural University, China (YNAU).


Assuntos
Neópteros , Humanos , Animais , China , Distribuição Animal
13.
Inorg Chem ; 63(9): 4078-4085, 2024 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-38390829

RESUMO

Providing efficient electronic transport channels has always been a promising strategy to mitigate the recombination of photogenerated charge carriers. In this study, a heterostructure composed of a semiconductor/photoinactive-metal-organic framework (MOF) was constructed to provide innovative channels for electronic transport. Prepared using a previously reported method ( Angew. Chem., Int. Ed. 2016, 55, 15301-15305) with slight modifications to temperature and reaction time, the CuS@HKUST-1 hollow cuboctahedron was synthesized. The CuS@HKUST-1 heterostructure possessed a well-defined cuboctahedral morphology with a uniform size of about 500 nm and a hollow structure with a thickness of around 50 nm. The CuS nanoparticles were uniformly distributed on the HKUST-1 shell. Structural characterization in cooperation with density functional theory (DFT) calculations revealed that CuS can effectively transfer photogenerated electrons to HKUST-1. CuS@HKUST-1 hollow cuboctahedrons were first introduced to the photocatalytic cycloaddition reaction of CO2 with epoxides, demonstrating excellent photocatalytic activity and stability at mild conditions (room temperature, solvent-free, and 1 atm CO2 pressure). The high photocatalytic performance of the CuS@HKUST-1 hollow cuboctahedron could be attributed to (1) the unique hollow cuboctahedron morphology, which provided a large specific surface area (693.1 m2/g) and facilitated the diffusion and transfer of reactants and products; and (2) CuS@HKUST-1 providing electronic transport channels from CuS to HKUST-1, which could enhance the adsorption and activation of CO2. Cu2+ carrying surplus electrons can activate CO2 to CO2-. The charge separation and transfer in the photocatalytic process can also be effectively promoted. This work provides a cost-effective and environmentally friendly approach for CO2 utilization reactions under ambient conditions, addressing the critical issue of rising atmospheric CO2 levels.

14.
Int J Biol Macromol ; 260(Pt 1): 129446, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38409770

RESUMO

Effects of Epiphyllum oxypetalum (DC.) Haw polysaccharide (EP) on physicochemical/digestive properties of tapioca starch (TS) were investigated, and its effects on final quality of TS-based foods were further determined. Results showed EP significantly decreased gelatinization enthalpy (3.92 to 2.11 J/g) and increased breakdown (302 to 382 cp), thereby inducing the gelatinization of TS. Meanwhile, EP decreased setback viscosity (324 to 258 cp), suggesting the retrogradation of TS paste was inhibited. Rheological determination results suggested EP had an impact on the viscoelasticity of TS paste. Moreover, particle size distribution showed EP increased size of TS by cross-linking. Additionally, the suitable addition of EP ameliorated the microstructure and decreased the crystal diffraction peak area of TS gel. Infrared spectroscopy results revealed EP modified the above properties of TS by hydrogen bonds and non-covalent forces. Furthermore, EP inhibited the in vitro digestion of TS paste. Using taro balls as TS-based food model, appropriate addition of EP (0.10 %) improved texture properties, frozen storage stability and color of samples. The present results can not only facilitate the understanding of the modification mechanism of EP on the properties of TS, but also induce the burgeoning of starchy products and the possible application of EP in foods.


Assuntos
Manihot , Manihot/química , Amido/química , Viscosidade , Alimentos , Termodinâmica
15.
J Asian Nat Prod Res ; 26(2): 214-227, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38353486

RESUMO

Five new sesquiterpenoids, including a campherenane-type (1), a bergamotane-type (2), a drimane-type (3), and two bisabolane-type (5-6) sesquiterpenoids have been isolated from Biscogniauxia sp. 71-10-1-1. Their structures were determined by spectroscopic analyses, quantum chemical ECD calculations,13C chemical shifts calculations, and X-ray crystallography. This is the first report of campherenane-type and drimane-type sesquiterpenoids from Biscogniauxia. Furthermore, the anti-inflammatory assays of all compounds are evaluated, and the results showed that compounds 3 and 7 exhibited the effects against the production of the pro-inflammatory cytokine TNF-α.


Assuntos
Sesquiterpenos , Xylariales , Sesquiterpenos/farmacologia , Sesquiterpenos/química , Sesquiterpenos Policíclicos , Estrutura Molecular
16.
Materials (Basel) ; 17(4)2024 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-38399053

RESUMO

Cylinder liners, considered a crucial component of internal combustion (IC) engines, often require excellent mechanical properties to ensure optimal engine performance under elevated temperatures, pressures, and varying loads. In this work, a new low-alloy cylinder liner, incorporating a low content of molybdenum, copper, and chromium into gray cast iron, was fabricated using a centrifugal casting process. Subsequently, the heat treatment processes were designed to achieve bainite microstructures in the cylinder liner through rapid air cooling, isothermal transformation, and tempering. The effects of different air-cooling rates and tempering temperatures on the microstructure evolution and mechanical properties of cylinder liner were investigated. The results revealed that during the supercooled austenite transformation process, rapid air cooling at a rate of 14.5-23.3 °C/s can effectively bypass the formation of pearlitic structures and directly induce the formation of bainite structures. Once the temperature exceeded 480-520 °C, hardness and tensile strength increased with the temperature increase owing to the enhancement of the lower bainite content, the reduction of residual austenite, and the precipitation of the fine hard carbides in the matrix. With temperatures above 520-550 °C, the carbide and lower bainite organization coarsened, thereby reducing the hardness and tensile strength of the material. Therefore, the optimal heat treatment parameters were rapid cooling at 14.5-23.3 °C/s rate to obtain bainite, and tempering of 480-520 °C for finer and more uniform bainite. In addition, the results of the characterization of the mechanical properties of the cylinder liner after heat treatment showed that the hardness, tensile strength, and wear resistance were improved with the refinement of the bainite.

17.
J Agric Food Chem ; 72(7): 3793-3799, 2024 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-38327062

RESUMO

Carotenoids, as a type of tetraterpene compound, have been widely used in food, medical, and health areas owing to their antioxidant, immune enhancement, and disease risk reduction effects. Rhodosporidium toruloides is a promising oleaginous red yeast that can industrially synthesize carotenoids. In this study, the effects of different light exposure times and intervals on carotenoid production by R. toruloides Z11 were first investigated. Results showed that a higher carotenoid content (1.29 mg/g) can be achieved when R. toruloides Z11 was exposed to light for 12 h per day, which was increased by 1.98 times compared with that of dark cultivation. Transcriptome profiling revealed that light stress could effectively promote the gene expression levels of GGPS1 and AL1 in the carotenoid biosynthesis pathway and phr in the DNA photolysis pathway of R. toruloides. This work will provide a molecular foundation to further improve the production efficiency of carotenoids by genetic engineering.


Assuntos
Basidiomycota , Rhodotorula , Engenharia Genética , Rhodotorula/genética , Carotenoides/metabolismo , Basidiomycota/genética , Basidiomycota/metabolismo
18.
Comput Med Imaging Graph ; 113: 102333, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38281420

RESUMO

Dynamic Contrast Enhanced Magnetic Resonance Imaging (DCE-MRI) can be used as a non-invasive method for the assessment of myocardial perfusion. The acquired images can be utilised to analyse the spatial extent and severity of myocardial ischaemia (regions with impaired microvascular blood flow). In the present paper, we propose a novel generalisable spatio-temporal hierarchical Bayesian model (GST-HBM) to automate the detection of ischaemic lesions and improve the in silico prediction accuracy by systematically integrating spatio-temporal context information. We present a computational inference procedure with an adequate trade-off between accuracy and computational efficiency, whereby model parameters are sampled from the posterior distribution with Gibbs sampling, while lower-level hyperparameters are selected using model selection strategies based on the Watanabe Akaike information criterion (WAIC). We have assessed our method on both synthetic (in silico) data with known gold-standard and 12 sets of clinical first-pass myocardial perfusion DCE-MRI datasets. We have also carried out a comparative performance evaluation with four established alternative methods: Gaussian mixture model (GMM), opening and closing operations based on Gaussian mixture model (GMMC&Omax), Markov random field constrained Gaussian mixture model (GMM-MRF) and model-based hierarchical Bayesian model (M-HBM). Our results show that the proposed GST-HBM method achieves much higher in silico prediction accuracy than the established alternative methods. Furthermore, this method appears to provide a more robust delineation of ischaemic lesions in datasets affected by spatially variant noise.


Assuntos
Doença da Artéria Coronariana , Imageamento por Ressonância Magnética , Humanos , Teorema de Bayes , Imageamento por Ressonância Magnética/métodos
19.
Mol Neurobiol ; 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38224443

RESUMO

Neurons and microglia are sensitive to cerebral microcirculation and their responses play a crucial part in the pathological processes, while they are also the main target cells of many drugs used to treat brain diseases. Rapamycin exhibits beneficial effects in many diseases; however, whether it can affect neuronal injury or alter the microglial activation after global cerebral ischemia remains unclear. In this study, we performed global cerebral ischemia combined with rapamycin treatment in CX3CR1GFP/+ mice and explored the effects of rapamycin on neuronal deficit and microglial activation. Our results showed that rapamycin reduced neuronal loss, neurodegeneration, and ultrastructural damage after ischemia by histological staining and transmission electron microscopy (TEM). Interestingly, rapamycin suppressed de-ramification and proliferation of microglia and reduced the density of microglia. Immunofluorescence staining indicated that rapamycin skewed microglial polarization toward an anti-inflammatory state. Furthermore, rapamycin as well suppressed the activation of astrocytes. Meanwhile, quantitative real-time polymerase chain reaction (qRT-PCR) analyses revealed a significant reduction of pro-inflammatory factors as well as an elevation of anti-inflammatory factors upon rapamycin treatment. As a result of these effects, behavioral tests showed that rapamycin significantly alleviated the brain injury after stroke. Together, our study suggested that rapamycin attenuated neuronal injury, altered microglial activation state, and provided a more beneficial immune microenvironment for the brain, which could be used as a promising therapeutic approach to treat ischemic cerebrovascular diseases.

20.
Nat Prod Rep ; 2024 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-38265076

RESUMO

Covering: up to August 2023Terpenoids, which are widely distributed in animals, plants, and microorganisms, are a large group of natural products with diverse structures and various biological activities. They have made great contributions to human health as therapeutic agents, such as the anti-cancer drug paclitaxel and anti-malarial agent artemisinin. Accordingly, the biosynthesis of this important class of natural products has been extensively studied, which generally involves two major steps: hydrocarbon skeleton construction by terpenoid cyclases and skeleton modification by tailoring enzymes. Additionally, fungi (Ascomycota and Basidiomycota) serve as an important source for the discovery of terpenoids. With the rapid development of sequencing technology and bioinformatics approaches, genome mining has emerged as one of the most effective strategies to discover novel terpenoids from fungi. To date, numerous terpenoid cyclases, including typical class I and class II terpenoid cyclases as well as emerging UbiA-type terpenoid cyclases, have been identified, together with a variety of tailoring enzymes, including cytochrome P450 enzymes, flavin-dependent monooxygenases, and acyltransferases. In this review, our aim is to comprehensively present all fungal terpenoid cyclases identified up to August 2023, with a focus on newly discovered terpenoid cyclases, especially the emerging UbiA-type terpenoid cyclases, and their related tailoring enzymes from 2015 to August 2023.

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