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1.
Animals (Basel) ; 14(17)2024 Aug 25.
Artículo en Inglés | MEDLINE | ID: mdl-39272253

RESUMEN

The literature shows that maternal stress can influence behavior and immune function in F1. Yet, most studies on these are from the laboratory, and replicated studies on the mechanisms by which maternal stress drives individual characteristics are still not fully understood in wild animals. We manipulated high- and low-density parental population density using large-scale field enclosures and examined behavior and immune traits. Within the field enclosures, we assessed anti-keyhole limpet hemocyanin immunoglobulin G (anti-KLH IgG) level, phytohemagglutinin (PHA) responses, hematology, cytokines, the depressive and anxiety-like behaviors and prevalence and intensity of coccidial infection. We then collected brain tissue from juvenile voles born at high or low density, quantified mRNA and protein expression of corticotropin-releasing hormone (CRH) and glucocorticoid receptor gene (NR3C1) and measured DNA methylation at CpG sites in a region that was highly conserved with the prairie vole CRH and NR3C1 promoter. At high density, we found that the F1 had a lower DNA methylation level of CRH and a higher DNA methylation level of NR3C1, which resulted in an increase in the expression levels of the CRH mRNA and protein expression and further reduced the expression levels of the NR3C1 mRNA and protein expression, and ultimately led to have delayed responses to acute immobilization stress. Juvenile voles born at high density also reduced anti-KLH IgG levels and PHA responses, increased cytokines, and depressive and anxiety-like behaviors, and the effects further led to higher coccidial infection. From the perspective of population density inducing the changes in behavior and immunity at the brain level, our results showed a physiological epigenetic mechanism for population self-regulation in voles. Our results indicate that altering the prenatal intrinsic stress environment can fundamentally impact behavior and immunity by DNA methylation of HPA-axis genes and can further drive population fluctuations in wild animals.

2.
Front Public Health ; 12: 1324260, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39290411

RESUMEN

Recent research has highlighted the beneficial effects of urban green spaces on physical and mental health. This study focused on the hospital population and innovatively subdivided the population into four groups: doctors, caregivers, patients and nurses. A total of 96 volunteers participated in this virtual reality experiment to assess the restoration of a linear canopy landscape and a landscape with different levels of hydrodynamics through interactive audiovisual immersion. We utilized pre-research method, brainwave monitoring technique, psychological scales, observation and interviews in this experiment. The research identified five key findings. First, both linear canopy landscapes and those with low to medium hydrodynamic forces significantly enhance physiological and psychological restoration for all groups, with the most substantial physiological benefits observed in doctors and patients, and the greatest psychological relief noted in caregivers. Second, landscapes with medium hydrodynamic forces yield higher restorative effects than those with low forces in hospital settings. Third, green landscapes with medium and low-density canopies prove more conducive to patient recovery compared to those with high-density canopies. Fourth, the inclusion of bird songs does not markedly affect physiological restoration across the hospital groups. Finally, landscapes that incorporate elements of water dynamics, open skies, and lightly foliated canopies draw significant interest from all groups involved. This study advocates for the integration of natural blue and green elements into hospital environments as complementary therapeutic interventions, aiming to alleviate stress and promote health recovery among hospital communities.


Asunto(s)
Hidrodinámica , Humanos , Masculino , Femenino , Adulto , Persona de Mediana Edad , Realidad Virtual , Hospitales , Recursos Audiovisuales
3.
Digit Health ; 10: 20552076241271812, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39114114

RESUMEN

Background: The deep integration of digital technology and healthcare services has propelled the healthcare system into the era of digital health. However, vulnerable populations in the field of information technology, they face challenges in benefiting from the digital dividends brought by digital health, leading to the emerging phenomenon of the "health digital divide." Methods: This study utilized the sample of 3547 urban from the 2021 Chinese Social Survey data for analysis. Models were constructed with digital access divide, digital usage divide, and digital outcome divide for urban residents, and structural equation modeling was implemented for analysis. Results: The impact ß coefficients (95% CI) of urban residents' digital access on the frequency of digital use, internet healthcare utilization, and patient experience were (ß = 0.737, P < 0.001), (ß = 0.047, P < 0.05), and (ß = 0.079, P < 0.001), respectively. Urban elderly groups were at a disadvantage in digital access and usage (ß = -0.007, ß = -0.024, and ß = -0.004), as well as those with lower educational levels (ß = 0.109, ß = 0.162, and ß = 0.045). However, these two factors did not have a significant direct impact on the patient experience in urban areas. Conclusions: The health digital divide of urban residents exhibits a cascading effect, primarily manifested in the digital access and usage divide. To bridge health digital divide among urban residents, efforts must be made to improve digital access and usage among the elderly and those with lower educational levels.

4.
Molecules ; 29(13)2024 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-38999048

RESUMEN

Self-powered photoelectrochemical (PEC) ultraviolet photodetectors (UVPDs) are promising for next-generation energy-saving and highly integrated optoelectronic systems. Constructing a heterojunction is an effective strategy to increase the photodetection performance of PEC UVPDs because it can promote the separation and transfer of photogenerated carriers. However, both crystal defects and lattice mismatch lead to deteriorated device performance. Here, we introduce a structural regulation strategy to prepare TiO2 anatase-rutile heterophase homojunctions (A-R HHs) with oxygen vacancies (OVs) photoanodes through an in situ topological transformation of titanium metal-organic framework (Ti-MOF) by pyrolysis treatment. The cooperative interaction between A-R HHs and OVs suppresses carrier recombination and accelerates carrier transport, thereby significantly enhancing the photodetection performance of PEC UVPDs. The obtained device realizes a high on/off ratio of 10,752, a remarkable responsivity of 24.15 mA W-1, an impressive detectivity of 3.28 × 1011 Jones, and excellent cycling stability. More importantly, under 365 nm light illumination, a high-resolution image of "HUST" (the abbreviation of Harbin University of Science and Technology) was obtained perfectly, confirming the excellent optical imaging capability of the device. This research not only presents an advanced methodology for constructing TiO2-based PEC UVPDs, but also provides strategic guidance for enhancing their performance and practical applications.

5.
J Phys Condens Matter ; 36(28)2024 Apr 18.
Artículo en Inglés | MEDLINE | ID: mdl-38574683

RESUMEN

In recent years, higher-order topological phases have attracted great interest in various fields of physics. These phases have protected boundary states at lower-dimensional boundaries than the conventional first-order topological phases due to the higher-order bulk-boundary correspondence. In this review, we summarize current research progress on higher-order topological phases in both crystalline and non-crystalline systems. We firstly introduce prototypical models of higher-order topological phases in crystals and their topological characterizations. We then discuss effects of quenched disorder on higher-order topology and demonstrate disorder-induced higher-order topological insulators. We also review the theoretical studies on higher-order topological insulators in amorphous systems without any crystalline symmetry and higher-order topological phases in non-periodic lattices including quasicrystals, hyperbolic lattices, and fractals, which have no crystalline counterparts. We conclude the review by a summary of experimental realizations of higher-order topological phases and discussions on potential directions for future study.

6.
Anal Biochem ; 689: 115502, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38453047

RESUMEN

Myoglobin (Myo), creatine kinase-MB (CKMB), and cardiac troponin I (cTnI) are crucial biomarkers for diagnosing acute myocardial infarction (AMI) The accurate and rapid detection of these three targets can greatly improve the prognosis of AMI patients. Herein, this study developed a microfluidic immunofluorescence method that can detect all three targets in 10-15 min. Ultrasonic atomization and spray technology are used to modify the surface of the injection-molded microfluidic chip (MFC), which effectively solves the problem of biological cross-linking and antibody immobilization on the MFC surface. In addition, it improves the hydrophilicity of the chip surface, thus enhancing fluid self-driving effect. The linear response towards Myo, CKMB and cTnI range from 5 ng/mL to 500 ng/mL, 1 ng/mL to 70 ng/mL, and 0.05 ng/mL to 30 ng/mL, respectively. The intra-batch precision is ≤ 10%, and the inter-batch precision is ≤ 15%. Furthermore, this method shows good consistency compared with the BECKMAN ACCESS2 chemiluminescent immunoanalyzer. The present work provides an AMI diagnostic method with high sensitivity, good repeatability, high accuracy and simple operation, which can satisfy the needs of clinical diagnosis, and shows promising application prospects.


Asunto(s)
Microfluídica , Infarto del Miocardio , Humanos , Infarto del Miocardio/diagnóstico , Forma MB de la Creatina-Quinasa , Pronóstico , Troponina I , Biomarcadores , Mioglobina , Sensibilidad y Especificidad
7.
Food Chem ; 439: 138101, 2024 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-38043286

RESUMEN

In milk, fat exists in the form of milk fat globules (MFGs). The average size (average fat globules of different particle sizes) is the most common parameter when describing MFG size. There are different views on whether there is a correlation between MFG size and milk fat content. Is the MFG size correlated with milk fat content in ruminants? To address this question, we conducted two experiments. In experiment Ⅰ, dairy cows (n = 40) and dairy goats (n = 30) were each divided into a normal group and a low-fat group according to the milk fat content. In experiment Ⅱ, dairy cows (n = 16) and dairy goats (n = 12) were each divided into a normal group and a conjugated linoleic acid (CLA)-induced low-fat group. The normal groups were fed a basal diet, and the CLA-induced low-fat groups were fed the basal diet + 300 g/d CLA (cows) or the basal diet + 90 g/d CLA (goats). In both experiments, we determined the correlation between MFG size and milk composition and MFG distribution. The results showed that in the normal and low-fat groups of cows and goats, MFG size was not correlated with milk fat, protein, or lactose content or fat-to-protein ratio. Additionally, there was no difference in the distribution of large, medium, and small MFGs (P > 0.05). However, in the CLA-induced low-fat groups, we found a correlation between MFG size and milk fat content and fat-to-protein ratio (R2 > 0.3). Moreover, there was a significant change in the size distribution of MFGs. Therefore, in natural milk, MFG size was not correlated with milk fat content. Following CLA supplementation, MFG size was correlated with milk fat content. Our findings revealed that CLA and not milk fat affects MFG distribution and size.


Asunto(s)
Lactancia , Ácidos Linoleicos Conjugados , Femenino , Bovinos , Animales , Ácidos Grasos/metabolismo , Leche/metabolismo , Dieta/veterinaria , Cabras/metabolismo , Ácidos Linoleicos Conjugados/metabolismo , Suplementos Dietéticos
8.
J Dairy Sci ; 106(12): 9868-9878, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37678795

RESUMEN

Rumen-protected choline (RPC) supplementation in the periparturient period has in some instances prevented and alleviated fatty liver disease in dairy cows. Mechanistically, however, it is unclear how choline prevents the accumulation of lipid droplets (LD) in liver cells. In this study, primary liver cells isolated from liver tissue obtained via puncture biopsy from 3 nonpregnant mid-lactation multiparous Holstein cows (∼160 d postpartum) were used. Analyses of LD via oil red O staining, protein abundance via Western blotting, and phospholipid content and composition measured by thin-layer chromatography and HPLC/mass spectrometry were performed in liver cells cultured in choline-deficient medium containing 150 µmol/L linoleic acid for 24 h. In a subsequent experiment, lipophagy was assessed in liver cells cultured with 30, 60, or 90 µmol/L choline-chloride. All data were analyzed statistically using SPSS 20.0 via t-tests or one-way ANOVA. Compared with liver cells cultured in Dulbecco's Modified Eagle Medium alone, choline deficiency increased the average diameter of LD (1.59 vs. 2.10 µm), decreased the proportion of small LD (<2 µm) from 75.3% to 56.6%, and increased the proportion of large LD (>4 µm) from 5.6% to 15.0%. In addition, the speed of LD fusion was enhanced by the absence of choline. Among phospholipid species, the phosphatidylcholine (PC) content of liver cells decreased by 34.5%. Seventeen species of PC (PC [18:2_22:6], PC [15:0_16:1], PC [14:0_20:4], and so on) and 6 species of lysophosphatidylcholine (LPC; LPC [15:0/0:0]), PC (22:2/0:0), LPC (20:2/0:0), and so on] were decreased, while PC (14:1_16:1) and LPC (0:0/20:1) were increased. Choline deficiency increased the triglyceride (TAG) content (0.57 vs. 0.39 µmol/mg) in liver cells and increased the protein abundance of sterol regulatory element binding protein 1, sterol regulatory element binding protein cleavage activation protein, and fatty acid synthase by 23.5%, 17%, and 36.1%, respectively. Upon re-supplementation with choline, the phenotype of LD (TAG content, size, proportion, and phospholipid profile) was reversed, and the ratio of autophagy marker LC3II/LC3I protein was significantly upregulated in a dose-dependent manner. Overall, at least in vitro in mid-lactation cows, these data demonstrated that PC synthesis is necessary for normal LD formation, and both rely on choline availability. According to the limitation of the source of liver cells used, further work should be conducted to ascertain that these effects are applicable to liver cells from postpartum cows, the physiological stage where the use of RPC has been implemented for the prevention and treatment of fatty liver.


Asunto(s)
Enfermedades de los Bovinos , Deficiencia de Colina , Femenino , Bovinos , Animales , Deficiencia de Colina/metabolismo , Deficiencia de Colina/veterinaria , Gotas Lipídicas/metabolismo , Colina/farmacología , Colina/metabolismo , Lactancia/fisiología , Hígado/metabolismo , Fosfolípidos/análisis , Suplementos Dietéticos/análisis , Dieta/veterinaria , Rumen/metabolismo , Leche/química , Enfermedades de los Bovinos/metabolismo
9.
Sci Total Environ ; 895: 165139, 2023 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-37379916

RESUMEN

Short-wall block backfill mining can effectively control the movement of overlying strata, prevent water loss and utilize waste gangue materials. However, heavy metal ions (HMI) of gangue backfill materials in the mined-out area can be released and transported to the underlying aquifer, causing pollution of water resources in the mine. Accordingly, with short-wall block backfill mining technology, this study analyzed the sensitivity of gangue backfill materials to the environment. The pollution mechanism of gangue backfill materials to water resources was revealed, and the transport rules of HMI were explored. The regulation and control methods of water pollution in the mine were then concluded. The design method of backfill ratio for comprehensive protection of overlying and underlying aquifers was proposed. The results show that the release concentration of HMI, the gangue particle size, the floor lithology, the burial depth of the coal seam, and the depth of the floor fractures were the main factors that affected the transport behaviors of HMI. After long-term immersion, HMI of gangue backfill materials underwent hydrolysis and were released constantly. HMI were subjected to the coupled action of seepage, concentration, and stress and then driven by water head pressure and gravitational potential energy to transported downward along the pore and fracture channels in the floor with mine water as the carrier. Meanwhile, the transport distance of HMI increased with increasing release concentration of HMI, the permeability of the floor stratum, and the depth of floor fractures. Still, it decreased with increasing gangue particle size and the burial depth of the coal seam. On that basis, external-internal cooperative control methods were proposed to prevent the pollution of gangue backfill materials to mine water. Furthermore, the design method of the backfill ratio for comprehensive protection of overlying and underlying aquifers was proposed.

10.
Food Funct ; 14(5): 2304-2312, 2023 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-36752527

RESUMEN

In mammary epithelial cells, milk fat is synthesized as lipid droplets and secreted in the form of globules. Milk fat globules (MFGs) are covered by a lipid-protein membrane known as the milk fat globule membrane (MFGM). We randomly divided 12 Holstein cows into control and conjugated linoleic acid (CLA) groups. The control group was fed a basal diet, while the CLA group was fed the basal diet + CLA (15 g per kg DM) for 10 days. Cow performance, milk composition, and MFG size were measured daily. On day 10, we extracted MFGM proteins (n = 3) and identified them via quantitative proteomic analysis. We investigated the effects of the MFGM proteins from control and CLA-treated milk on the lipid droplet formation in MAC-T cells. Compared with the control group, the CLA group had reduced milk fat content (3.39 g/100 mL vs. 2.45 g/100 mL) and MFG size parameters (D[4,3] of 3.85 µm vs. 3.37 µm; D[3,2] of 3.24 µm vs. 2.83 µm). The specific surface area (SSA) increased in the CLA group. A total of 361 differentially expressed proteins were identified in the CLA group by iTRAQ quantitative proteomic analysis. Among these proteins, 100 were upregulated and 251 were downregulated (p < 0.05). In MAC-T cells, CLA-MFGM proteins increased the diameter of the lipid droplets to 1.32 µm. CLA-MFGM proteins decreased the proportion of the small lipid droplets (15.33% vs. 47.78%) and increased the proportion of the large lipid droplets (25.04% vs. 11.65%). CLA-MFGM proteins promoted lipid droplet fusion. Therefore, MFGM proteins play an important role in the regulation of the lipid droplet size.


Asunto(s)
Ácidos Linoleicos Conjugados , Gotas Lipídicas , Femenino , Bovinos , Animales , Gotas Lipídicas/metabolismo , Proteínas de la Leche/metabolismo , Proteómica , Glucolípidos/metabolismo , Células Epiteliales/metabolismo , Lactancia , Ácidos Linoleicos Conjugados/farmacología
11.
Sci Rep ; 12(1): 11783, 2022 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-35821389

RESUMEN

Aiming at the problems that it is difficult to predict rock burst accurately in engineering practice and the implementation parameters of rock burst prevention measures depend on some empirical formulas, in order to study the advantages and disadvantages of different in-situ modification mechanisms deeply, determine the applicable conditions of unusual in-situ modification measures, and provide a theoretical basis for forming adaptive in-situ modification control schemes. Two kinds of modified control methods using the same foundation involve engineering scale and indoor scale. With the help of scale transformation, the whole failure process analysis test of bearing rock samples was carried out. The results show that various modification measures can effectively control the properties, and realize "hard-rock softening or soft-rock hardening" by changing the physical and mechanical parameters of the target rock sample. Compared with the control group, the automatic parameters of rocks deteriorated significantly under different modification measures. The evolution law of carrying energy is similar. However, there are obvious diversity between various modification measures in plastic stage and post-peaking phase stage, which provides favorable conditions for rock burst prevention. Based on this, an adaptive modification control system was constructed. At the same time, filling materials is considered to increase the energy of post-peaking phase (non newtonian fluid: energy-absorbing materials), and further slow down the intensity of released energy within post-peaking phase stage. Because rock burst is characterized by rapid release of energy, non newtonian fluid has a good absorption effect on high-speed impact force. Therefore, in the design test, the effect of non newtonian fluid is realized by applying a high loading rate, and the evaluation of energy absorption effect of bearing rock samples filled with non newtonian fluid in borehole is considered.

12.
Ecol Evol ; 12(5): e8927, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35592070

RESUMEN

Density dependence in reproduction plays an important role in stabilizing population dynamics via immediate negative feedback from population density to reproductive output. Although previous studies have shown that negative density-dependent reproduction is associated with strong spacing behavior and social interaction between individuals, the proximal mechanism for generating negative density-dependent reproduction remains unclear. In this study, we investigated the effects of density-induced stress on reproduction in root voles. Enclosed founder populations were established by introducing 6 (low density) and 30 (high density) adults per sex into per enclosure (four enclosures per density in total) during the breeding season from April to July 2012 and from May to August 2015. Fecal corticosterone metabolite (FCM) levels, reproductive traits (recruitment rate and the proportion of reproductively active individuals), and founder population numbers were measured following repeated live trapping in both years. The number of founders was negatively associated with recruitment rates and the proportion of reproductively active individuals, displaying a negative density-dependent reproduction. FCM level was positively associated with the number of founders. The number of founder females directly affected the proportion of reproductive females, and directly and indirectly through their FCM levels affected the recruitment rate; the effect of the number of male founders on the proportion of reproductive males was mediated by their FCM level. Our results showed that density-induced stress negatively affected reproductive traits and that density-induced stress is one ecological factor generating negative density-dependent reproduction.

13.
Plant Signal Behav ; 17(1): 2005882, 2022 12 31.
Artículo en Inglés | MEDLINE | ID: mdl-34913407

RESUMEN

Seed germination and seedling development in nearly all orchid species rely on a symbiotic relationship with mycorrhizal fungi; however, this is not the case with all mycorrhizal fungi. This study aims to provide an understanding about the important role of mycorrhiza in seed germination and growth of Paphiopedilum barbigerum. Therefore, we isolated and identified endophytic fungi from the roots of wild P. barbigerum. The beneficial mycorrhizal fungi Epulorhiza sp. FQXY019 and Tulasnella calospora FQXY017 were screened by seed symbiotic germination tests and found to promote seed germination. However, only the seeds inoculated with FQXY019 progressed from the seed germination to rooting stage. This shows that mycorrhizal fungi and P. barbigerum have a specific relation at different growth phases. In addition, we selected FQXY019 and inoculated it into MS medium, B5 medium, OMA medium, and PDA medium. The results showed that FQXY019 co-cultured on PDA significantly promoted the increase in seedling fresh weight, leaf length, and root length (p < .01). Furthermore, it significantly promoted the root number and leaf number of seedlings compared with those co-cultured on MS, B5, and OMA media and control (p < .05). Thus, this study demonstrated the promoting effect of Epulorhiza sp. FQXY019 on seed germination and seedling development, making it an alternative method for the artificial propagation of P. barbigerum.


Asunto(s)
Micorrizas , Orchidaceae , Germinación , Orchidaceae/microbiología , Plantones , Semillas , Simbiosis
14.
Artículo en Inglés | MEDLINE | ID: mdl-34135982

RESUMEN

BACKGROUND: Rho-related coiled helix forming protein kinase (Rho-ROCK) and another important fibrogenic factor-PDGF play a critical role in collagen deposition in rat lung tissue. Yifei decoction (YFT), a Chinese herbal decoction, has been used to treat idiopathic pulmonary fibrosis (IPF) in clinical practice and has produced positive outcomes; however, convincing evidence is currently lacking. The present study aimed to investigate the effects of YFT combined with MitoQ in rats with IPF and to explore the underlying mechanism. METHODS: Rat IPF model was established by endotracheal injection of 5 mg/kg BleomycinA5 into the specific pathogen-free SD rats. MitoQ (6.5 µmol/kg once daily), YFT (10 ml/kg once daily), and MitoQ + YFT (6.5 µmol/kg + 10 ml/kg once daily) were used to treat the rat model for 4 weeks, respectively. The normal rats without IPF were used as the controls. After 4 weeks of drug treatment, lung histopathology was assessed. Immunohistochemistry was used to detect the expression of fibronectin and collagen IV in lung tissue. The expression of IL-6, IL-1ß, TNF-α, GSH-Px, SOD, MDA, and hydroxyproline was determined by enzyme-linked immunosorbent assay. The expressions of TGFß1, NOX4, PDGFR-ß, and ROCK1 were determined using real-time quantitative PCR and Western blot. RESULTS: After 4 weeks of drug treatment, comparison of the MitoQ + YFT group with the IPF group showed that lung injury scores, W/D, lung tissue hydroxyproline, fibronectin, collagen IV content, and IL-6, IL-1ß, TNF-α, and MDA levels were significantly lower (P < 0.05), as well as the expression of TGFß1, NOX4, PDGFR-ß, and ROCK1, but the activity of GSH-Px and SOD was higher (P < 0.05). CONCLUSION: MitoQ combined with YFT can improve lung injury in rats with pulmonary fibrosis by reducing the secretion of proinflammatory cytokines and inhibiting TGFß1/NOX4 and PDGF/ROCK signaling pathways. It may provide a new method for the treatment of pulmonary fibrosis.

15.
Phys Rev Lett ; 126(20): 206404, 2021 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-34110216

RESUMEN

Higher-order topological insulators are established as topological crystalline insulators protected by crystalline symmetries. One celebrated example is the second-order topological insulator in three dimensions that hosts chiral hinge modes protected by crystalline symmetries. Since amorphous solids are ubiquitous, it is important to ask whether such a second-order topological insulator can exist in an amorphous system without any spatial order. Here, we predict the existence of a second-order topological insulating phase in an amorphous system without any crystalline symmetry. Such a topological phase manifests in the winding number of the quadrupole moment, the quantized longitudinal conductance, and the hinge states. Furthermore, in stark contrast to the viewpoint that structural disorder should be detrimental to the higher-order topological phase, we remarkably find that structural disorder can induce a second-order topological insulator from a topologically trivial phase in a regular geometry. We finally demonstrate the existence of a second-order topological phase in amorphous systems with time-reversal symmetry.

16.
Nanomaterials (Basel) ; 11(1)2021 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-33435592

RESUMEN

For the development of spacecraft with long-servicing life in low earth orbit (LEO), high-temperature resistant polymer films with long-term atomic oxygen (AO) resistant features are highly desired. The relatively poor AO resistance of standard polyimide (PI) films greatly limited their applications in LEO spacecraft. In this work, we successfully prepared a series of novel AO resistant PI composite films containing nanocaged polyhedral oligomeric silsesquioxane (POSS) components in both the PI matrix and the fillers. The POSS-containing PI matrix film was prepared from a POSS-substituted aromatic diamine, N-[(heptaisobutyl-POSS)propyl]-3,5-diaminobenzamide (DABA-POSS) and a common aromatic diamine, 4,4'-oxydianline (ODA) and the aromatic dianhydride, pyromellitic dianhydride (PMDA) by a two-step thermal imidization procedure. The POSS-containing filler, trisilanolphenyl POSS (TSP-POSS) was added with the fixed proportion of 20 wt% in the final films. Incorporation of TSP-POSS additive apparently improved the thermal stability, but decreased the high-temperature dimensional stable nature of the PI composite films. The 5% weight loss temperature (T5%) of POSS-PI-20 with 20 wt% of DABA-POSS is 564 °C, and its coefficient of linear thermal expansion (CTE) is 81.0 × 10-6/K. The former is 16 °C lower and the latter was 20.0 × 10-6/K higher than those of the POSS-PI-10 film (T5% = 580 °C, CTE = 61.0 × 10-6/K), respectively. POSS components endowed the PI composite films excellent AO resistance and self-healing characteristics in AO environments. POSS-PI-30 exhibits the lowest AO erosion yield (Es) of 1.64 × 10-26 cm3/atom under AO exposure with a flux of 2.51 × 1021 atoms/cm2, which is more than two orders of magnitude lower than the referenced PI (PMDA-ODA) film. Inert silica or silicate passivation layers were detected on the surface of the PI composite films exposed to AO.

17.
Phys Rev Lett ; 127(26): 263004, 2021 Dec 24.
Artículo en Inglés | MEDLINE | ID: mdl-35029461

RESUMEN

Recent theoretical studies predict that structural disorder, serving as a bridge connecting a crystalline material to an amorphous material, can induce a topological insulator from a trivial phase. However, to experimentally observe such a topological phase transition is very challenging due to the difficulty in controlling structural disorder in a quantum material. Given experimental realization of randomly positioned Rydberg atoms, such a system is naturally suited to studying structural disorder induced topological phase transitions and topological amorphous phases. Motivated by the development, we study topological phases in an experimentally accessible one-dimensional amorphous Rydberg atom chain with random atom configurations. In the single-particle level, we find symmetry-protected topological amorphous insulators and a structural disorder induced topological phase transition, indicating that Rydberg atoms provide an ideal platform to experimentally observe the phenomenon using state-of-the-art technologies. Furthermore, we predict the existence of a gapless symmetry-protected topological phase of interacting bosons in the experimentally accessible system. The resultant many-body topological amorphous phase is characterized by a Z_{2} invariant.

18.
Brain Res ; 1748: 147070, 2020 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-32827549

RESUMEN

Hypoxic-ischemic encephalopathy (HIE) results in high neonatal mortality and severe neurological impairments, and its underlying molecular mechanism underwent extensive investigations. Long non-coding RNA (lncRNA) is considered to be an important regulator on brain development and many neurological diseases. Currently, little is known about the role of Vof-16 (lncRNA) in HIE. We detected the relative expression level of Vof-16 in the cortex and hippocampus of hypoxic-ischemic (HI) models whose successful establishment was verified by TTC staining. Then, Vof-16 knockout rats were generated using the CRISPR/Cas engineering technology to search the specific function of the Vof-16 through a series of behavioral evaluations including Neurological severity scores (NSS), Y-maze test, Morris water maze (MWW) test, open field test, and Rotarod test. The results demonstrated the expression of Vof-16 was substantially up-regulated in the cortex and hippocampus of rats with HI injury. Importantly, Vof-16 knockout facilitated the recovery from long-term HI induced nerve damage and neurobehavioral dysfunctions. In conclusion, this study suggests Vof-16 knockout is a promising treatment target for neonatal HIE.


Asunto(s)
Encéfalo/metabolismo , Hipoxia-Isquemia Encefálica/genética , Proteínas/genética , Recuperación de la Función/fisiología , Animales , Animales Recién Nacidos , Sistemas CRISPR-Cas , Técnicas de Inactivación de Genes , Hipoxia-Isquemia Encefálica/metabolismo , Aprendizaje por Laberinto/fisiología , Actividad Motora/fisiología , Proteínas/metabolismo , Ratas , Ratas Sprague-Dawley
19.
Phys Rev Lett ; 123(7): 076401, 2019 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-31491126

RESUMEN

We study amorphous systems with completely random sites and find that, through constructing and exploring a concrete model Hamiltonian, such a system can host an exotic phase of topological amorphous metal in three dimensions. In contrast to the traditional Weyl semimetals, topological amorphous metals break translational symmetry, and thus they cannot be characterized by the first Chern number defined based on the momentum space band structures. Instead, their topological properties will manifest in the Bott index and the Hall conductivity as well as the surface states. By studying the energy band and quantum transport properties, we find that topological amorphous metals exhibit a diffusive metal behavior. We further introduce a practical experimental proposal with electric circuits where the predicted phenomena can be observed using state-of-the-art technologies. Our results open the door to exploring topological gapless phenomena in amorphous systems.

20.
Polymers (Basel) ; 11(6)2019 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-31181709

RESUMEN

Protection of polymeric materials from the atomic oxygen erosion in low-earth orbit spacecrafts has become one of the most important research topics in aerospace science. In the current research, a series of novel organic/inorganic nanocomposite films with excellent atomic oxygen (AO) resistance are prepared from the phosphorous-containing polyimide (FPI) matrix and trisilanolphenyl polyhedral oligomeric silsesquioxane (TSP-POSS) additive. The PI matrix derived from 2,2'-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) and 2,5-bis[(4-amino- phenoxy)phenyl]diphenylphosphine oxide (BADPO) itself possesses the self-healing feature in AO environment. Incorporation of TSP-POSS further enhances the AO resistance of the FPI/TSP composite films via a Si-P synergic effect. Meanwhile, the thermal stability of the pristine film is maintained. The FPI-25 composite film with a 25 wt % loading of TSP-POSS in the FPI matrix exhibits an AO erosion yield of 3.1 × 10-26 cm3/atom after an AO attack of 4.0 × 1020 atoms/cm2, which is only 5.8% and 1.0% that of pristine FPI-0 film (6FDA-BADPO) and PI-ref (PMDA-ODA) film derived from 1,2,4,5-pyromellitic anhydride (PMDA) and 4,4'-oxydianline (ODA), respectively. Inert phosphorous and silicon-containing passivation layers are observed at the surface of films during AO exposure.

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