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1.
Nanoscale ; 16(8): 3817-3837, 2024 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-38327235

RESUMO

This review provides a comprehensive overview of the growth methodologies and neutron shielding applications of Boron Nitride Nanotubes (BNNTs). BNNTs have garnered significant attention because of their unique combination of high thermal stability, mechanical strength, and exceptional neutron absorption properties. Synthesis methods for BNNTs, including laser ablation, thermal plasma treatment, chemical vapour deposition (CVD), and ball milling have been thoroughly examined, highlighting their mechanisms, advantages, and challenges. Each method contributes uniquely to the quality and applicability of BNNTs in terms of scalability and production efficiency. This study focused on the applications of BNNTs in neutron absorption, particularly in aerospace engineering. BNNTs have shown promising potential in enhancing the safety and longevity of space missions by providing effective radiation protection. Furthermore, their potential in medical applications, particularly in Boron Neutron Capture Therapy (BNCT) for cancer treatment, has been explored. BNCT offers a targeted approach to cancer therapy by utilizing the high boron-10 content of BNNTs for precise and localized treatment. This review also provides an outlook on the future of BNNT research, emphasizing the need for more efficient growth methods to facilitate wider adoption and commercialization. The versatility of BNNTs across various fields, from space exploration to medical science, underscores their potential as materials of significant scientific and technological importance. As research progresses, BNNTs are expected to play a pivotal role in advancing materials science and offer innovative solutions to complex challenges.

2.
ACS Omega ; 8(24): 21514-21521, 2023 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-37360428

RESUMO

Highly crystalline double-walled boron nitride nanotubes (DWBNNTs ∼60%) were synthesized from ammonia borane (AB; H3B-NH3) precursors using a high-temperature thermal plasma method. The differences between the synthesized BNNTs using the hexagonal boron nitride (h-BN) precursor and AB precursor were compared using various techniques such as thermogravimetric analysis, X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, and in situ optical emission spectroscopy (OES). The synthesized BNNTs were longer and had fewer walls when the AB precursor was used than when the conventional method was used (with the h-BN precursor). The production rate significantly improved from ∼20 g/h (h-BN precursor) to ∼50 g/h (AB precursor), and the content of amorphous boron impurities was significantly reduced, implying a self-assembly mechanism of BN radicals rather than the conventional mechanism involving boron nanoballs. Through this mechanism, the BNNT growth, which was accompanied by an increased length, a decreased diameter, and a high growth rate, could be understood. The findings were also supported by in situ OES data. Considering the increased production yield, this synthesis method using AB precursors is expected to make an innovative contribution to the commercialization of BNNTs.

3.
Nanomaterials (Basel) ; 13(7)2023 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-37049287

RESUMO

The environmental problems in the world are attracting increasing amounts of attention, and heavy metal pollution in the water has become one of the focuses of the ecological environment. Molybdenum disulfide (MoS2) has excellent adsorption performance because of its extremely high specific surface area and unique active site structure, which has attracted an increasing amount of attention in the field of heavy metal disposal in various types of water. In this paper, two sorts of MoS2 nanoparticles, spherical and lamellar, were synthesized by different chemical methods. Their morphology and structure were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and a Raman spectrometer. The adsorption properties of two sorts of MoS2 nanoparticles for copper (Ⅱ) ions in water were investigated by changing the pH value, adsorption time, initial concentration of solution, adsorption temperature, etc. Finally, the adsorption mechanism was analyzed by kinetic, isothermal, and thermodynamic models. The results show that two microstructures of MoS2 nanoparticles can be used as efficient adsorption materials for removing heavy metal ions from water, although there are differences in adsorption capacity between them, which expands the theoretical basis of heavy metal adsorption in a water environment.

4.
Zhongguo Zhong Yao Za Zhi ; 48(2): 562-568, 2023 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-36725246

RESUMO

The manufacturing process of traditional Chinese medicine is subject to material fluctuation and other uncertain factors which usually cause non-optimal state and inconsistent product quality. Therefore, it is necessary to design and collect the quality-rela-ted physical parameters, process parameters, and equipment parameters in the whole manufacturing process of traditional Chinese medicine for digitization and modeling of the process. In this paper, a method for non-optimal state identification and self-recovering regulation was developed for active quality control in the manufacturing process of traditional Chinese medicine. Moreover, taking vacuum belt drying process as an example, a DQN algorithm-based intelligent decision model was established and verified and the implementation process was also discussed and studied. Thus, the process parameters-based self-optimization strategy discovery and path planning of optimal process control were rea-lized in this study. The results showed that the deep reinforcement learning-based artificial intelligence technology was helpful to improve the product quality consistency, reduce production cost, and increase benefit.


Assuntos
Medicamentos de Ervas Chinesas , Medicina Tradicional Chinesa , Inteligência Artificial , Controle de Qualidade , Algoritmos
5.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-970493

RESUMO

The manufacturing process of traditional Chinese medicine is subject to material fluctuation and other uncertain factors which usually cause non-optimal state and inconsistent product quality. Therefore, it is necessary to design and collect the quality-rela-ted physical parameters, process parameters, and equipment parameters in the whole manufacturing process of traditional Chinese medicine for digitization and modeling of the process. In this paper, a method for non-optimal state identification and self-recovering regulation was developed for active quality control in the manufacturing process of traditional Chinese medicine. Moreover, taking vacuum belt drying process as an example, a DQN algorithm-based intelligent decision model was established and verified and the implementation process was also discussed and studied. Thus, the process parameters-based self-optimization strategy discovery and path planning of optimal process control were rea-lized in this study. The results showed that the deep reinforcement learning-based artificial intelligence technology was helpful to improve the product quality consistency, reduce production cost, and increase benefit.


Assuntos
Medicina Tradicional Chinesa , Medicamentos de Ervas Chinesas , Inteligência Artificial , Controle de Qualidade , Algoritmos
6.
Int J Ophthalmol ; 15(7): 1035-1043, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35919335

RESUMO

AIM: To compare the damage of light-emitting diodes (LEDs) with different color rendering indexes (CRIs) to the ocular surface and retina of rats. METHODS: Totally 20 Sprague-Dawley (SD) rats were randomly divided into four groups: the first group was normal control group without any intervention, other three groups were exposed by LEDs with low (LED-L), medium (LED-M), and high (LED-H) CRI respectively for 12h a day, continuously for 4wk. The changes in tear secretion (Schirmer I test, SIt), tear film break-up time (BUT), and corneal fluorescein sodium staining (CFS) scores were compared at different times (1d before experiment, 2 and 4wk after the experiment). The histopathological changes of rat lacrimal gland and retina were observed at 4wk, and the expressions of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in lacrimal gland were detected by immunofluorescence method. RESULTS: With the increase of light exposed time, the CFS value of each light exposed group continued to increase, and the BUT and SIt scores continued to decrease, which were different from the control group, and the differences between the light exposed groups were statistically significant. Hematoxylin-eosin (HE) results showed that the lacrimal glands of each exposed group were seen varying degrees of acinar atrophy, vacuole distribution, increasing of eosinophil granules, etc.; the retina showed obvious reduction of photoreceptor cell layer and changes in retinal thickness; LED-L group has the most significant change in all tests. Immunofluorescence suggested that the positive expressions of TNF-α and IL-6 in the lacrimal glands of each exposed group were higher than those of the control group. CONCLUSION: LED exposure for 4wk can cause the pathological changes of lacrimal gland and retina of rats, and increase the expression of TNF-α and IL-6 in lacrimal gland, the degree of damage is negatively correlated with the CRI.

7.
Zhongguo Zhong Yao Za Zhi ; 47(12): 3402-3408, 2022 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-35851136

RESUMO

Chinese medicine pharmaceutical industry is in the process of digital and intelligent transformation. Intelligent methods are required for efficient analysis and mining of the valuable information in the history data including literature data, pharmaceutical big data, and expert knowledge. Therefore, it is urgent to establish a knowledge-driven intelligent system of pharmaceutical technologies of Chinese medicine for efficient supplying of high-quality Chinese medicinal products. The present study proposed the construction method of the knowledge base of Chinese medicine manufacturing, which was preliminarily established from literature mining, case-based reasoning, and real-time prediction based on vacuum belt drying process optimization. Integrating the technologies(such as deep learning, case-based reasoning, and simulation modeling), pharmaceutical mechanisms, and big data, the knowledge base of Chinese medicine manufacturing can realize knowledge automation and scientific decision-making. It provides an example for upgrading from experience-based manufacturing to intelligent Chinese medicine manufacturing.


Assuntos
Medicamentos de Ervas Chinesas , Medicina Tradicional Chinesa , Bases de Conhecimento , Controle de Qualidade , Tecnologia Farmacêutica
8.
J Pain ; 23(10): 1629-1645, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35691467

RESUMO

Recent studies have shown that the incidence of chronic primary pain including temporomandibular disorders (TMD) and fibromyalgia syndrome (FMS) often exhibit comorbidities. We recently reported that central sensitization and descending facilitation system contributed to the development of somatic pain hypersensitivity induced by orofacial inflammation combined with stress. The purpose of this study was to explore whether TMD caused by unilateral anterior crossbite (UAC) can induce somatic pain hypersensitivity, and whether the cholecystokinin (CCK) receptor-mediated descending facilitation system promotes hypersensitivity through neuron-glia cell signaling cascade. UAC evoked thermal and mechanical pain hypersensitivity of the hind paws from day 5 to 70 that peaked at week 4 post UAC. The expression levels of CCK1 receptors, interleukin-18 (IL-18) and IL-18 receptors (IL-18R) were significantly up-regulated in the L4 to L5 spinal dorsal horn at 4 weeks post UAC. Intrathecal injection of CCK1 and IL-18 receptor antagonists blocked somatic pain hypersensitivity. IL-18 mainly co-localized with microglia, while IL-18R mainly co-localized with astrocytes and to a lesser extent with neurons. These findings indicate that the signaling transduction between neurons and glia at the spinal cord level contributes to the descending pain facilitation through CCK1 receptors during the development of the comorbidity of TMD and FMS. PERSPECTIVE: CCK1 receptor-dependent descending facilitation may mediate central mechanisms underlying the development of widespread somatic pain via a reciprocal neuron-glial signaling cascade, providing novel therapeutic targets for the clinical treatment of TMD and FMS comorbidities.


Assuntos
Dor Crônica , Má Oclusão , Dor Nociceptiva , Receptor de Colecistocinina B , Animais , Colecistocinina/metabolismo , Dor Crônica/metabolismo , Hiperalgesia/metabolismo , Interleucina-18/metabolismo , Má Oclusão/metabolismo , Neuroglia/fisiologia , Neurônios , Dor Nociceptiva/metabolismo , Ratos , Ratos Sprague-Dawley , Receptor de Colecistocinina B/metabolismo , Receptores de Interleucina-18/metabolismo , Transdução de Sinais/fisiologia , Medula Espinal , Corno Dorsal da Medula Espinal/metabolismo
9.
Neural Regen Res ; 17(12): 2710-2716, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35662218

RESUMO

Necrostatin-1, an inhibitor of necroptosis, can effectively inhibit necrotic apoptosis in neurological diseases, which results in the inhibition of inflammation, endoplasmic reticulum stress, and reactive oxygen species production and substantial improvement of neurological function. However, the effects of necrostatin-1 on intraventricular hemorrhage (IVH) remain unknown. In this study, we established a mouse model of IVH by injecting autologous blood into the lateral ventricle of the brain. We also injected necrostatin-1 into the lateral ventricle one hour prior to IVH induction. We found that necrostatin-1 effectively reduced the expression levels of the necroptosis markers receptor-interacting protein kinase (RIP)1, RIP3, mixed lineage kinase domain-like protein (MLKL), phosphorylated (p)-RIP3, and p-MLKL and the levels of interleukin-1ß , interleukin-6, and tumor necrosis factor-α in the surrounding areas of the lateral ventricle. However, necrostatin-1 did not reduce ependymal ciliary injury or brain water content. These findings suggest that necrostatin-1 can prevent local inflammation and microglial activation induced by IVH but does not greatly improve prognosis.

10.
Nano Converg ; 9(1): 20, 2022 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-35552898

RESUMO

Highly crystalline and few-walled boron nitride nanotubes (BNNTs) had been synthesized by laser ablation using only ammonia borane as a precursor. As a molecular precursor, ammonia borane supplied both B and N atoms with a ratio of 1:1, and BNNTs were formed via the homogeneous nucleation of BN radicals, not the growth from boron nano-droplets, which is a generally accepted growth mechanism of the laser-grown BNNTs. Owing to the absence of amorphous boron impurities, the van der Waals interaction among BNNTs became effective and thus a BNNT fibers was formed spontaneously during the BNNT synthesis. The BNNT growth and the subsequent fiber formation are found to occur only at high pressures of a surrounding gas. The mechanism behind the critical role of pressure was elucidated from the perspective of reaction kinetics and thermal fluid behaviors. A polarized Raman study confirmed that the BNNT fiber formed exhibits a good alignment of BNNTs, which implies great potential for continuous production of high-quality BNNT fibers for various applications.

11.
Sci Adv ; 8(16): eabn0939, 2022 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-35452295

RESUMO

Theoretical considerations suggest that the strength of carbon nanotube (CNT) fibers be exceptional; however, their mechanical performance values are much lower than the theoretical values. To achieve macroscopic fibers with ultrahigh performance, we developed a method to form multidimensional nanostructures by coalescence of individual nanotubes. The highly aligned wet-spun fibers of single- or double-walled nanotube bundles were graphitized to induce nanotube collapse and multi-inner walled structures. These advanced nanostructures formed a network of interconnected, close-packed graphitic domains. Their near-perfect alignment and high longitudinal crystallinity that increased the shear strength between CNTs while retaining notable flexibility. The resulting fibers have an exceptional combination of high tensile strength (6.57 GPa), modulus (629 GPa), thermal conductivity (482 W/m·K), and electrical conductivity (2.2 MS/m), thereby overcoming the limits associated with conventional synthetic fibers.

12.
Bioresour Technol ; 349: 126883, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35192946

RESUMO

Here, a low-cost acid-base and temperature tolerant algal bloom derived activated carbon (ABAC) was successfully prepared to remove rhodamine B (RhB) from water. The ABAC exhibited maximum adsorption capacity of RhB (1101 ± 11 mg/g), higher than that of laboratory-prepared rape straw activated carbon (176 ± 5 mg/g) and commercial activated carbon (489 ± 5 mg/g). It is attributed to larger surface area and mesoporous structure of the ABAC. Furthermore, the effective adsorption of RhB by using ABAC was achieved at a wide range of solution pH (3.2-10.8) and temperature(25-50 °C). The mass transfer resistance of RhB adsorption process well depicted by Langmuir model was controlled by external mass transfer. The adsorption process involved both secondly chemisorption (H-bonds and π-π interaction) and dominated physisorption. Four dyes in river water were efficiently removed. This work provides a promising approach for developing high-absorption biomass materials for actual dye wastewater treatment.


Assuntos
Carvão Vegetal , Poluentes Químicos da Água , Adsorção , Carvão Vegetal/química , Corantes , Eutrofização , Concentração de Íons de Hidrogênio , Cinética , Temperatura , Águas Residuárias , Poluentes Químicos da Água/química
13.
Zhongguo Zhong Yao Za Zhi ; 47(23): 6417-6422, 2022 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-36604887

RESUMO

In view of the relatively low representativeness of manual sampling inspection, and long time-consuming in oven detection of moisture content, which delayed the subsequent production period, this paper proposed a scheme for rapid moisture quantitative detection for Chinese medicinal materials by microwave transmission technology, and took 8 different types of Chinese medicinal mate-rials as examples to analyze the feasibility and reliability of the scheme for the detection results of moisture content of the whole package of Chinese medicine. In the experiment, the least square method was used to establish the measurement model of microwave absorption rate-moisture content for each kind of medicinal material. The results showed that the microwave transmission measurement of moisture content achieved high-precision measurement of the moisture content of Schisandrae Chinensis Fructus, Ziziphi Spinosae Semen, Poria, Pheretima, Lilii Bulbus, Scutellariae Radix, and Galli Gigerii Endothelium Corneum. The measurement model of Ziziphi Spinosae Semen had the highest accuracy, and the R~2 and root mean square error of the validation set were 0.951 5 and 0.15%, respectively. At the same time, this study found that the microwave absorption intensity of animal medicines including Pheretima and Galli Gigerii Endothelium Corneum was much weaker than that of plant medicines such as Schisandrae Chinensis Fructus, but there was also a good linear relationship between microwave absorption and moisture content, which proved the universality of this method. However, this method was not suitable for Phellodendri Chinensis Cortex because its package contained iron wire. For the whole package of medicinal materials with uniform density and no metal inside, the microwave transmission technology for moisture content measurement can be used to detect the moisture content, which is an effective alternative method to detect the moisture content of medicinal materials.


Assuntos
Medicamentos de Ervas Chinesas , Animais , Micro-Ondas , Reprodutibilidade dos Testes , Medicina Tradicional Chinesa , Tecnologia
14.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-954487

RESUMO

Atherosclerosis (AS) is a chronic and progressive arterial disease. It is an important cause of the occurrence and development of cardiovascular and cerebrovascular diseases. With the development of Traditional Chinese Medicine (TCM), TCM has many advantages in the therapy of AS, with less adverse reactions. Studies have shown that TCM can resist AS, and the mechanism mainly belongs to regulating lipid metabolism, anti-lipid peroxidation, anti-inflammation, anticoagulation, and protecting the structure and function of vascular endothelial cells. The mechanism of TCM for AS is warranted to be studied systematically, and the chemical components need to be further clarified.

15.
Front Immunol ; 12: 729501, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34721391

RESUMO

Background: Atopic march refers to the natural history of atopic dermatitis (AD) in infancy followed by subsequent allergic rhinitis and asthma in later life. Respiratory viruses interact with allergic sensitization to promote recurrent wheezing and the development of asthma. We aimed to evaluate whether influenza vaccination reduces asthma risk in people with AD. Methods: This cohort study was conducted retrospectively from 2000 to 2013 by the National Health Insurance Research Database (NHIRD). Patients with newly diagnosed AD (International Classification of Diseases, Ninth Revision, Clinical Modification code 691) were enrolled as the AD cohort. We matched each vaccinated patient with one non-vaccinated patient according to age and sex. We observed each participant until their first asthma event, or the end of the study on December 31, 2013, whichever came first. Results: Our analyses included 4,414 people with a mean age of 53 years. Of these, 43.8 were male. The incidence density of asthma was 12.6 per 1,000 person-years for vaccinated patients, and 15.1 per 1000 person-years for non-vaccinated patients. The adjusted hazard ratio (aHR) of asthma in the vaccinated cohort relative to the non-vaccinated cohort was 0.69 (95% CI = 0.55-0.87). Vaccinated patients had a lower cumulative incidence of asthma than unvaccinated patients. Vaccinated participants in all age and sex groups trended toward a lower risk of asthma. People will reduce more asthma risk when taking shots every year. Conclusion: Influenza vaccination was associated with lower asthma risk in patients with AD.


Assuntos
Asma/prevenção & controle , Dermatite Atópica/epidemiologia , Vacinas contra Influenza/administração & dosagem , Adulto , Idoso , Asma/diagnóstico , Asma/epidemiologia , Bases de Dados Factuais , Dermatite Atópica/diagnóstico , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Fatores de Proteção , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Taiwan/epidemiologia , Fatores de Tempo , Vacinação , Adulto Jovem
16.
Regen Biomater ; 8(6): rbab047, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34513004

RESUMO

Recent studies have shown that 3D printed scaffolds integrated with growth factors can guide the growth of neurites and promote axon regeneration at the injury site. However, heat, organic solvents or cross-linking agents used in conventional 3D printing reduce the biological activity of growth factors. Low temperature 3D printing can incorporate growth factors into the scaffold and maintain their biological activity. In this study, we developed a collagen/chitosan scaffold integrated with brain-derived neurotrophic factor (3D-CC-BDNF) by low temperature extrusion 3D printing as a new type of artificial controlled release system, which could prolong the release of BDNF for the treatment of spinal cord injury (SCI). Eight weeks after the implantation of scaffolds in the transected lesion of T10 of the spinal cord, 3D-CC-BDNF significantly ameliorate locomotor function of the rats. Consistent with the recovery of locomotor function, 3D-CC-BDNF treatment could fill the gap, facilitate nerve fiber regeneration, accelerate the establishment of synaptic connections and enhance remyelination at the injury site.

17.
Front Aging Neurosci ; 13: 697029, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34335232

RESUMO

Background: Essential tremor (ET) is a common movement disorder among elderly individuals worldwide and is occasionally associated with a high risk for mild cognitive impairment and dementia. This retrospective study aimed to determine the clinical outcome of unilateral magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy in Chinese patients with ET. Methods: In total, 31 male and 17 female patients with drug-refractory ET were enrolled in this research study from January 2017 to September 2019. The severity of tremor and disability were assessed using the Clinical Rating Scale for Tremor (CRST) within a 2-year follow-up period. Results: The mean age of the participants was 59.14 ± 13.5 years. The mean skull density ratio (SDR) was 0.5 ± 0.1. The mean highest temperature was 57.0 ± 2.4°C. The mean number of sonications was 10.0 ± 2.6. The average maximum energy was 19,710.5 ± 8,624.9 J. The total CRST scores and sub-scores after MRgFUS thalamotomy significantly reduced during each follow-up (p < 0.001). All but four (8.3%) of the patients had reversible adverse events (AEs) after the procedure. Conclusions: MRgFUS had sustained clinical efficacy 2 years after treatment for intractable ET. Only few patients presented with thalamotomy-related AEs including numbness, weakness, and ataxia for an extended period. Most Chinese patients were treated safely and effectively despite their low SDR.

18.
Zhongguo Zhong Yao Za Zhi ; 46(9): 2350-2355, 2021 May.
Artigo em Chinês | MEDLINE | ID: mdl-34047140

RESUMO

In this paper, we first introduced the concept of digital twin(DT) based key technologies for intelligent manufacturing of traditional Chinese medicine(TCM) and applied DT in two case studies of novel extraction equipment for traditional Chinese medicine and drying equipment for Chinese medicine pills to illustrate the advantages of DT in development of new pharmaceutical technology and optimization of pharmaceutical equipment structure. Furthermore, we discussed the feasibility to adopt DT in the production process of TCM for formation of data-driven real-time optimization of production process and dynamic prediction `of operation and maintenance service. The "ruled" production mode based on data and driven by algorithm was constructed to realize the technical scheme of quality perception, evaluation, prediction, intelligent control and intelligent decision-making in product life cycle.


Assuntos
Medicamentos de Ervas Chinesas , Medicina Tradicional Chinesa , Comércio , Controle de Qualidade , Tecnologia Farmacêutica
19.
Nat Commun ; 12(1): 2396, 2021 04 22.
Artigo em Inglês | MEDLINE | ID: mdl-33888704

RESUMO

Arrestins recognize different receptor phosphorylation patterns and convert this information to selective arrestin functions to expand the functional diversity of the G protein-coupled receptor (GPCR) superfamilies. However, the principles governing arrestin-phospho-receptor interactions, as well as the contribution of each single phospho-interaction to selective arrestin structural and functional states, are undefined. Here, we determined the crystal structures of arrestin2 in complex with four different phosphopeptides derived from the vasopressin receptor-2 (V2R) C-tail. A comparison of these four crystal structures with previously solved Arrestin2 structures demonstrated that a single phospho-interaction change results in measurable conformational changes at remote sites in the complex. This conformational bias introduced by specific phosphorylation patterns was further inspected by FRET and 1H NMR spectrum analysis facilitated via genetic code expansion. Moreover, an interdependent phospho-binding mechanism of phospho-receptor-arrestin interactions between different phospho-interaction sites was unexpectedly revealed. Taken together, our results provide evidence showing that phospho-interaction changes at different arrestin sites can elicit changes in affinity and structural states at remote sites, which correlate with selective arrestin functions.


Assuntos
Receptores de Vasopressinas/metabolismo , beta-Arrestina 1/metabolismo , Cristalografia por Raios X , Células HEK293 , Humanos , Mutação , Ressonância Magnética Nuclear Biomolecular , Fosfopeptídeos/química , Fosfopeptídeos/metabolismo , Fosforilação , Conformação Proteica em alfa-Hélice , Domínios Proteicos/genética , Receptores de Vasopressinas/química , Receptores de Vasopressinas/ultraestrutura , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/ultraestrutura , beta-Arrestina 1/genética , beta-Arrestina 1/isolamento & purificação , beta-Arrestina 1/ultraestrutura
20.
RSC Adv ; 11(60): 38152-38160, 2021 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-35498094

RESUMO

Macroscopic assemblies of carbon nanotubes (CNTs) usually have a poor alignment and a low packing density due to their hierarchical structure. To realize the inherent properties of CNTs at the macroscopic scale, the CNT assemblies should have a highly aligned and densified structure. Shear-aligning processes are commonly employed for this purpose. This work investigates how shear flows affect the rearrangement of CNT bundles in macroscopic assemblies. We propose that buckling behavior of CNT bundles in a shear flow causes the poor alignment of CNT bundles and a low packing density of CNT assemblies; the flow pattern and the magnitude of shear stress induced by the flow are key factors to regulate this buckling behavior. To obtain CNT assemblies with a high packing density, the CNTs should undergo a laminar flow that has a sufficiently low shear stress. Understanding the effect of shear flow on the structure of CNT bundles may guide improvement of fabrication strategies.

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