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1.
Arch Microbiol ; 206(2): 74, 2024 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-38253939

RESUMEN

A bacteriophage BD49 specific for Citrobacter braakii was screened out and purified by double-layer plate method. It consists of a polyhedral head of 93.1 ± 1.2 nm long and 72.9 ± 4.2 nm wide, tail fibers, collar, sheath and baseplate. The bacteriophage was identified by morphology observed with transmission electron microscope (TEM), whole genome sequencing carried out by Illumina next generation sequencing (NGS) technique, and gene annotation based on Clusters of Orthologous Groups of proteins (COG) database. It was identified primarily as a member of Caudovirales by morphology and further determined as Caudovirales, Myoviridae, and Citrobacter bacteriophage by alignment of its whole genome sequence with the NCBI database and establishment of phylogenetic tree. The bacteriophage showed good environmental suitability with optimal multiplicity of infection (MOI) of 0.01, proliferation time of 80 min, optimum living temperature of 30-40 °C, and living pH of 5-10. In addition, it exhibited synergistic effect with ciprofloxacin against C. braakii in antibacterial tests.


Asunto(s)
Antibacterianos , Bacteriófagos , Antibacterianos/farmacología , Bacteriófagos/genética , Filogenia , Citrobacter/genética
2.
Angew Chem Int Ed Engl ; : e202411629, 2024 Jul 05.
Artículo en Inglés | MEDLINE | ID: mdl-38966872

RESUMEN

Mechanochromic functionality realized via the force-responsive mechanophores in polymers has great potential for damage sensing and information storage. Mechanophores with the ability to recognize multiple stimuli for tunable chromic characteristics are highly sought after for versatile sensing ability and color programmability. Nevertheless, the majority of mechanophores are based on single-component chromophores with limited sensitivity, or require additional fabrication technology for multi-modal chromism. Here, we report a novel multifunctional mechanophore capable of vividly detectable and tunable mechanochromism in polymers. This synergistic optical coupling relies on strategically fusing rhodamine and spiropyran (Rh-SP), and tethering polymer chains on both subunits. The mechanochromic behaviors of the Rh-SP-linked polymers under sonication and compression are thoroughly evaluated in response to changes in force and the light-controlled relaxation process. Non-sequential ring-opening of the two subunits under force is identified, endowing high-contrast mechanochromism. Light-induced differential ring-closing reactions of the two subunits, together with the acidichromism of the SP moiety, are employed to engineer elastomers with programmable and wide-spectrum colors. Our work presents an effective strategy for highly appreciable and regulable mechanochromic functionality, and also provides new insights into the rupture mechanisms of π-fused mechanophores, as well as how the stimuli history controls stress accumulation in polymers.

3.
Phys Chem Chem Phys ; 25(23): 15807-15814, 2023 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-37254748

RESUMEN

Heating affects the interfacial properties of two-dimensional nanomaterials, especially when they interact with biomolecules. Here, we theoretically studied the dynamic processes driving single-strand DNA (ssDNA) molecules from the hydrophilic to hydrophobic regions on the graphene oxide (GO) surface by heating, as reported by recent experiments. This was accomplished by using multi-sample molecular dynamics simulations in the NVT ensemble, with the temperature increasing from 300 K to 350 K. When the temperature increased, the lifetime of hydrogen bonds between water molecule and oxygen-containing groups on the GO surface decreased from 10.04 ps to 6.86 ps, and the end-to-end distance of 4-mer and 8-mer ssDNA molecules also decreased. This indicated that heating facilitated the breaking/formation of hydrogen bonds and enhanced the flexibility of ssDNA molecules. By heating, active hydrogen bonding first led to unbalanced interactions between the ssDNA molecule and GO surface, and the enhanced flexibility allowed the ssDNA molecule to release stress by moving on the GO surface and relaxing its structure. The ssDNA molecule constantly adjusted its structure by a competition between intra and inter π-π stacking structures. With dynamic cooperation of hydrogen bonding and π-π stacking, the ssDNA molecule moved from the hydrophilic to hydrophobic regions. Our results offer fundamental interfacial science insights into the effects of heating on the interactions between biomolecules and two-dimensional nanomaterials.


Asunto(s)
Grafito , Calefacción , ADN de Cadena Simple , Agua/química , Simulación de Dinámica Molecular , Grafito/química , Interacciones Hidrofóbicas e Hidrofílicas
4.
Angew Chem Int Ed Engl ; 62(11): e202218785, 2023 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-36642693

RESUMEN

We report a versatile mechanophore exhibiting a vividly detectable, light-regulable multicolor mechanochromism. Such optical features rely on the synergistic coupling of mechanochromic bis-rhodamine (Rh) and photochromic bisthienylethene (BTE). Poly(methyl acrylate)s incorporating this bis-mechanophore can be mechanically activated under sonication. The relative distribution of the two distinctly colored and fluorescent Rh ring-opening products is altered with different magnitudes of applied force. Orthogonal use of the photochromic reaction of the BTE core can strengthen the mechanochromism and gate the mechanofluorescence in polymers. Due to increased conjugation offered by the BTE linker, both force- and light-induced optical signals display high contrast. Combined DFT simulated and experimental results reveal that the three subunits (two Rhs and one BTE) in this chromophore are activated sequentially, thus generating switchable three-colored forms and gradient optical responses.

5.
J Am Chem Soc ; 144(37): 17120-17128, 2022 09 21.
Artículo en Inglés | MEDLINE | ID: mdl-36070612

RESUMEN

The unique topological features of Piezo proteins underlie the lever-like cellular mechanotransduction mechanism. This knowledge inspires us to seek topological/geometric control of mechanochromophores with unprecedentedly amplified, synergistic changes in polymers to serve as ideal stress probes. Here, by judicious placement of two spirolactam rings into aminobenzopyranoxanthene, a series of stereo- and regio-isomeric rhodamine-like mechanophores are developed. With two labile bonds closely coupled into one rigidified scaffold, these π-fused bis-mechanophores enable mechanochromic polymers, featuring cooperative bond scission, low rupture force (lower than rhodamine), and geometry-controlled ring-opening reactivity. Sonication, single-molecule force spectroscopy experiments, and density functional theory calculations provide insight into the force-color relationship and rationalize how the difference in reactivity of the four isomeric mechanophores is affected by their molecular geometry and thermodynamic equilibrium. Our strategy based on the aromatic fusion of bis-mechanophore promises a modular approach to isomeric mechanophores for cooperative bond scission. Also, important insights into internal and external factors governing tandem mechanochemical reactions are gained.


Asunto(s)
Mecanotransducción Celular , Polímeros , Fenómenos Mecánicos , Polímeros/química , Rodaminas , Termodinámica
6.
Arch Microbiol ; 204(6): 310, 2022 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-35536516

RESUMEN

Glycosidic bond of C-glycosides is difficult to be broken due to its chemical stability. Screening specific microbe from microbiota is a practical way to deglycosylate these compounds. In this study, a new strain W974-1 which is capable of cleaving C-glycosidic bonds was isolated from human gut microbiota by spread plate method. It deglycosylates flavonoid 8-C-glycosides such as orientin and vitexin to their aglycones with the enzymes secreted outside the bacterial cells. This strain was identified as Enterococcus avium by 16S rDNA sequencing, physiological and biochemical characterization.


Asunto(s)
Microbioma Gastrointestinal , Glicósidos , Flavonoides , Humanos , Intestinos/microbiología
7.
Macromol Rapid Commun ; 42(1): e2000442, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33029850

RESUMEN

A series of nanocomposite elastomers are prepared by dispersing surface-modified silica Janus nanoparticles into semi-interpenetrating network (Semi-IPN) of polyurethane/polyethyl methacrylate. Benefiting from the hierarchically crosslinked structures that consist of physical interlocking mediated by hydrogen-bond-rich silica Janus nanoparticles and permanent crosslinking by Semi-IPN, these elastomers exhibit excellent mechanical properties. Moreover, the Janus nanosheet is found more effective in strengthening and toughening the Semi-IPN, in comparison to Janus hollow sphere. Since 1,2-dioxetane is covalently embedded in these elastomers as a mechanoluminescent stress probe, stress transfer between the polymer and Janus nanoparticles and the toughening mechanism can be illuminated, which offer exciting opportunities to study the failure process of complex polymer nanocomposites with high spatial and temporal resolution.


Asunto(s)
Nanopartículas Multifuncionales , Dióxido de Silicio , Metacrilatos , Polímeros , Poliuretanos
8.
Lancet Oncol ; 21(7): 904-913, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-32479787

RESUMEN

BACKGROUND: Patients with cancer are a high-risk population in the COVID-19 pandemic. We aimed to describe clinical characteristics and outcomes of patients with cancer and COVID-19, and examined risk factors for mortality in this population. METHODS: We did a retrospective, multicentre, cohort study of 205 patients with laboratory-confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and with a pathological diagnosis of a malignant tumour in nine hospitals within Hubei, China, from Jan 13 to March 18, 2020. All patients were either discharged from hospitals or had died by April 20, 2020. Clinical characteristics, laboratory data, and cancer histories were compared between survivors and non-survivors by use of χ2 test. Risk factors for mortality were identified by univariable and multivariable logistic regression models. FINDINGS: Between Jan 13 and Mar 18, 2020, 205 patients with cancer and laboratory-confirmed SARS-CoV-2 infection were enrolled (median age 63 years [IQR 56-70; range 14-96]; 109 [53%] women). 183 (89%) had solid tumours and 22 (11%) had haematological malignancies. The median duration of follow-up was 68 days (IQR 59-78). The most common solid tumour types were breast (40 [20%] patients), colorectal (28 [14%]), and lung cancer (24 [12%]). 54 (30%) of 182 patients received antitumour therapies within 4 weeks before symptom onset. 30 (15%) of 205 patients were transferred to an intensive care unit and 40 (20%) died during hospital admission. Patients with haematological malignancies had poorer prognoses than did those with solid tumours: nine (41%) of 22 patients with haematological malignancies died versus 31 (17%) of 183 patients with solid tumours (hazard ratio for death 3·28 [95% CI 1·56-6·91]; log rank p=0·0009). Multivariable regression analysis showed that receiving chemotherapy within 4 weeks before symptom onset (odds ratio [OR] 3·51 [95% CI 1·16-10·59]; p=0·026) and male sex (OR 3·86 [95% CI 1·57-9·50]; p=0·0033) were risk factors for death during admission to hospital. INTERPRETATION: Patients with cancer and COVID-19 who were admitted to hospital had a high case-fatality rate. Unfavourable prognostic factors, including receiving chemotherapy within 4 weeks before symptom onset and male sex, might help clinicians to identify patients at high risk of fatal outcomes. FUNDING: National Natural Science Foundation of China.


Asunto(s)
Infecciones por Coronavirus/mortalidad , Infecciones por Coronavirus/patología , Neoplasias/mortalidad , Neoplasias/patología , Neumonía Viral/mortalidad , Neumonía Viral/patología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Betacoronavirus , COVID-19 , China/epidemiología , Infecciones por Coronavirus/terapia , Femenino , Humanos , Masculino , Persona de Mediana Edad , Neoplasias/terapia , Pandemias , Neumonía Viral/terapia , Pronóstico , Estudios Retrospectivos , Factores de Riesgo , SARS-CoV-2 , Índice de Severidad de la Enfermedad , Resultado del Tratamiento , Adulto Joven
9.
Fish Shellfish Immunol ; 104: 663-672, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32497725

RESUMEN

Fish tend to rely more on their innate immunity to executing defense against viral infection by inducing antiviral gene production. However, the expression pattern and underlying mechanism of fish antiviral responses have yet to be fully defined. In the present study, an in vitro viral infection model was established by exposing head kidney-derived macrophages of large yellow croaker to virus analog, poly(I:C). Transcriptome analysis indicated that poly(I:C) appeared to induce potent antiviral activity featuring dominant interferon a3 (IFNa3) expression through activation of toll-like receptors (TLRs)/TIR-domain-containing adapter-inducing interferon-ß (TRIF) and retinoic acid-inducible gene I-like receptors (RLRs)/mitochondrial antiviral signaling protein (MAVS) pathways. Inhibition of nuclear factor κB (NF-κB) and stimulator of interferon genes (STING)/interferon regulatory factor 3 (IRF3) pathways diminished the expression of IFNa3. Mechanistically, transcription factors including p65 and IRF3 could promote expression of IRF3, and activated IRF3 alone further increased the transcriptional activity of IFNa3. We also characterized the promoter of IFNa3 with direct IRF3 binding site which was sufficient to render the transcription of IFNa3. This effect was attenuated after deletion or mutation of the IRF3 binding sites. Taken together, our findings illustrate the distinct transcriptional profiling of fish macrophages triggered by poly(I:C). Also, this work provides new insights into the molecular mechanism underpinning coordinated activation of pathogen recognition and signaling transduction in the antiviral responses of non-model fish species.


Asunto(s)
Proteínas de Peces/metabolismo , Inmunidad Innata , Macrófagos/inmunología , Perciformes/inmunología , Animales , Perfilación de la Expresión Génica , Riñón Cefálico/inmunología , Poli I-C/farmacología , Transducción de Señal
10.
Angew Chem Int Ed Engl ; 59(25): 9940-9945, 2020 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-31872529

RESUMEN

5,6,12,13-Tetraazaperopyrenes with different number of tert-butyl groups (c-TAPP-T, c-TAPP-H) were synthesized, via four-fold Bischler-Napieralski cyclization as the key step. As deduced from the single-crystal structures and optical properties, N-doping and substitution type allow for a precise control of intermolecular interactions. Compared to the reported 1,3,8,10-tetraazaperopyrenes, significantly different packing modes were found in 5,6,12,13-tetraazaperopyrenes. Going from c-TAPP-T to c-TAPP-H, two additional tert-butyl groups lead to different preferential growth directions, affording 1D and 2D microcrystals, respectively. Most importantly, both microcrystals exhibit excellent optical waveguide properties with extraordinarily low loss coefficients and unique polarization features. Although c-TAPP-H possesses a rigid and planar core, its crystals display an exceptional mechanochromic fluorescence, which, again, depends on the mode of molecular packing.

11.
Angew Chem Int Ed Engl ; 57(21): 6161-6165, 2018 05 22.
Artículo en Inglés | MEDLINE | ID: mdl-29600531

RESUMEN

A novel type of discotic polycyclic aromatic hydrocarbon (PAH) based on an enlarged dibenzo[a,c]phenazine core has been developed. The large conjugated mesogenic core with increased dipole moment derived from S,N heteroatoms facilitates the formation of highly ordered columnar superstructures both in solution and bulk. Columnar mesophases, including liquid crystal (LC) and plastic crystal (PC) assemblies could form unprecedentedly based on the same PAH core. The cores are delicately modulated by the peripherical alkoxy chains. Both mesogens have mechanochromic fluorescent (MCF) character, which is also structure dependent and correlated with the different mesophase formation. For the first time, MCF properties can be realized in such a large conjugated mesogenic system.

12.
Sci Total Environ ; : 174602, 2024 Jul 08.
Artículo en Inglés | MEDLINE | ID: mdl-38986709

RESUMEN

Traditional mining practices not only cause severe environmental issues, but also face the problem of insufficient production capacity of gold to meet its growing demand. The proposed alternative strategies for gold production, such as the extraction of gold from seawater, still keep a formidable challenge due to their strong dependence on adsorbent materials with high capacity, selectivity, and sensitivity, while also needing to meet the demands of being environmentally friendly and cost-effective. In practice, the direct extraction of gold from seawater is limited by its extremely low yield and high energy expenditure. However, if the combination of gold extraction techniques with seawater desalination can substantially reduce the energy consumption, the extraction of gold from seawater will become economical and feasible. In this paper, we evaluate the feasibility of marine gold extraction using reduced graphene oxide membranes (rGOM) during the seawater desalination process. The rGOM can adsorb almost all Au3+ from the solutions with trace concentrations of Au3+ ranging from 10 ppb to 200 ppb. The adsorption quantity is linearly related to the concentration, indicating that the adsorption capacity of rGOM is much higher than the total amount of Au3+ in the solution. Additionally, the rGOM can selectively adsorb 99 % of Au3+ in the mixed solution while hardly adsorbing other common elements in seawater. More importantly, the rGOM exhibits the long-term stability over 30 days when being immersed in the solution, making it directly compatible with the existing seawater desalination processes. These specific properties allow the rGOM to be an ideal candidate for combining the extraction of gold from seawater with seawater desalination processes. Our findings provide a methodology for enhancing the economic efficiency of the extraction of gold from seawater and hold promise for addressing the problem of gold scarcity.

13.
J Phys Chem B ; 128(6): 1385-1393, 2024 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-38294417

RESUMEN

The aggregation of monomeric amyloid ß protein (Aß) into oligomers and amyloid plaque in the brain is associated with Alzheimer's disease. The hydrophobic central core Aß16-22 has been widely studied due to its essential role in the fibrillization of full-length Aß peptides. Compared to the homogeneous antiparallel structure of Aß16-22 at the late stage, the early-stage prefibrillar aggregates contain varying proportions of different ß structures. In this work, we studied the appearance probabilities of various self-assembly structures of Aß16-22 and the effects of Zn2+ on these probabilities by replica exchange molecular dynamics simulations. It was found that at room temperature, Aß16-22 can readily form assembled ß-sheet structures in pure water, where a typical antiparallel arrangement dominates (24.8% of all sampled trimer structures). The addition of Zn2+ to the Aß16-22 solution will dramatically decrease the appearance probability of antiparallel trimer structures to 12.5% by disrupting the formation of the Lys16-Glu22 salt bridge. Meanwhile, the probabilities of hybrid antiparallel/parallel structures increase. Our simulation results not only reveal the competition between antiparallel and parallel structures in the Aß16-22 oligomers but also show that Zn2+ can affect the oligomer structures. The results also provide insights into the role of metal ions in the self-assembly of short peptides.


Asunto(s)
Enfermedad de Alzheimer , Péptidos beta-Amiloides , Humanos , Péptidos beta-Amiloides/química , Enfermedad de Alzheimer/metabolismo , Simulación de Dinámica Molecular , Conformación Proteica en Lámina beta , Zinc , Fragmentos de Péptidos/química
14.
J Diabetes ; 16(1): e13465, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37646268

RESUMEN

BACKGROUND AND AIMS: The traditional treatment of diabetic wounds is unsatisfactory. Exosomes isolated from bone marrow mesenchymal stem cells (BMSCs) promote the healing of diabetic wounds. However, whether the exosomes secreted by interferon (IFN)-γ-pretreated BMSCs have an enhanced therapeutic effect on diabetic wound healing and the relevant mechanisms remain unclear. METHODS: In this study, we isolated exosomes from the corresponding supernatants of BMSCs with (IExos) or without IFN-γ treatment (NExos). Human umbilical vein endothelial cells (HUVECs) were used to investigate the proliferation, migration, and tube formation under different treatments in vitro. Diabetic mice were induced by intraperitoneal administration of streptozotocin, and a circular full-thickness dermal defect was then made on the back of each mouse, followed by a multisite subcutaneous injection of phosphate buffered saline or exosomes. Hematoxylin-eosin (H&E) staining, Masson's trichrome staining, and histological analysis were performed to assess the speed and quality of wound healing. RESULTS: NExos treatment accelerated the healing of diabetic wounds by promoting angiogenesis in vivo and in vitro, and IExos exhibited superior therapeutic efficiency. MicroRNA (miR)-126-3p was significantly increased in IExos, and exosomal miR-126-3p promoted angiogenesis and diabetic wound healing via its transfer to HUVECs. miR-126-3p regulates SPRED1 by directly targeting the 3'-UTR. Mechanistically, IFN-γ-pretreated BMSCs secreted miR-126-3p-enriched exosomes, which enhanced the function of HUVECs and promoted angiogenesis via the SPRED1/Ras/Erk pathway. CONCLUSION: Exosomal miR-126-3p secreted from IFN-γ-pretreated BMSCs exhibited higher therapeutic efficacy than NExos in diabetic wound healing by promoting angiogenesis via the SPRED1/Ras/Erk axis.


Asunto(s)
Diabetes Mellitus Experimental , Exosomas , MicroARNs , Humanos , Ratones , Animales , MicroARNs/genética , Diabetes Mellitus Experimental/patología , Exosomas/genética , Exosomas/metabolismo , Cicatrización de Heridas , Células Endoteliales de la Vena Umbilical Humana/metabolismo , Proliferación Celular , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Proteínas Adaptadoras Transductoras de Señales/farmacología
15.
Am J Chin Med ; 52(4): 905-923, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38790086

RESUMEN

Recommendations on the use of acupuncture in managing low back pain (LBP) vary across different guidelines. The methodological quality of existing systematic reviews and meta-analyses on this topic also demonstrates considerable diversity, potentially leading to biased conclusions. Therefore, we comprehensively searched PubMed, EMBASE, Web of Science, Cochrane Database of Systematic Reviews, and Chinese National Knowledge Infrastructure (CNKI) databases and conducted an umbrella review. Scrutiny was performed to ascertain whether primary studies within the systematic reviews and meta-analyses adhered to our inclusion criteria, followed by a meticulous reanalysis of pertinent data. Participant numbers, heterogeneity, publication bias, and excessive significance were taken into account when assessing the credibility of the evidence. For robustness, sensitivity analysis was performed using the leave-one-out method. The results of the umbrella review yielded highly suggestive evidence in favor of the immediate and short-term analgesic effects of acupuncture, with suggestive evidence supporting intermediate-term analgesic effects. However, the effectiveness of acupuncture on disability improvement has demonstrated weak to suggestive evidence. Evidence supporting the enhancement of quality of life by acupuncture is limited. The leave-one-out analysis corroborated the robustness of the meta-analysis, further confirming the credibility of the findings. This umbrella review indicated that the most significant advantage of acupuncture for LBP is its capacity to reduce pain.


Asunto(s)
Terapia por Acupuntura , Dolor de la Región Lumbar , Humanos , Dolor de la Región Lumbar/terapia , Calidad de Vida , Resultado del Tratamiento
16.
Neurosci Biobehav Rev ; 162: 105735, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38821153

RESUMEN

This systematic review investigates the impact of meditation on neural responses to pain, as measured by functional magnetic resonance imaging (fMRI). Up to March 2024, we conducted searches across four databases for human studies implementing fMRI to assess the efficacy of meditation for pain relief. Eighteen studies met the inclusion criteria. Our systematic review indicates that activation of the insula, anterior cingulate cortex, and orbitofrontal cortex is positively associated with meditation for pain relief, while activity in regions like the amygdala and medial prefrontal cortex is negatively correlated with pain relief. Meta-analyses consistently reveal the involvement of various brain regions, including the insula, putamen, amygdala, anterior cingulate cortex, precentral gyrus, postcentral gyrus, inferior parietal lobule, superior temporal gyrus, inferior frontal gyrus, and caudate nucleus, in meditation-induced alleviation of pain. These findings suggest ccthat meditation acts on specific brain regions related to pain, mood, and cognition, providing insight into the potential mechanisms underlying the pain-alleviating effects of meditation on both pain sensations and emotional experiences.


Asunto(s)
Imagen por Resonancia Magnética , Meditación , Humanos , Manejo del Dolor , Dolor/fisiopatología , Dolor/diagnóstico por imagen , Encéfalo/diagnóstico por imagen , Encéfalo/fisiología , Encéfalo/fisiopatología
17.
Nat Chem ; 16(3): 446-455, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38052946

RESUMEN

Azobenzene has been widely explored as a photoresponsive element in materials science. Although some studies have investigated the force-induced isomerization of azobenzene, the effect of force on the rupture of azobenzene has not been explored. Here we show that the light-induced structural change of azobenzene can also alter its rupture forces, making it an ideal light-responsive mechanophore. Using single-molecule force spectroscopy and ultrasonication, we found that cis and trans para-azobenzene isomers possess contrasting mechanical properties. Dynamic force spectroscopy experiments and quantum-chemical calculations in which azobenzene regioisomers were pulled from different directions revealed that the distinct rupture forces of the two isomers are due to the pulling direction rather than the energetic difference between the two isomers. These mechanical features of azobenzene can be used to rationally control the macroscopic fracture behaviours of polymer networks by photoillumination. The use of light-induced conformational changes to alter the mechanical response of mechanophores provides an attractive way to engineer polymer networks of light-regulatable mechanical properties.

18.
Mediators Inflamm ; 2013: 354087, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23431240

RESUMEN

The present study was carried out to investigate the effects and mechanisms of polydatin (PD) in septic mice. The model of cecal ligation and puncture (CLP-)induced sepsis was employed. Pretreatment of mice with PD (15, 45, and 100 mg/kg) dose-dependently reduced sepsis-induced mortality and lung injury, as indicated by alleviated lung pathological changes and infiltration of proteins and leukocytes. In addition, PD inhibited CLP-induced serum tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) production, lung cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase isoform (iNOS) protein expressions and NF-κB activation. Notably, PD upregulated the expression and activity of heme oxygenase (HO-)1 in lung tissue of septic mice. Further, the protective effects of PD on sepsis were abrogated by ZnPP IX, a specific HO-1 inhibitor. These findings indicated that PD might be an effective antisepsis drug.


Asunto(s)
Glucósidos/uso terapéutico , Hemo-Oxigenasa 1/metabolismo , Lesión Pulmonar/tratamiento farmacológico , Lesión Pulmonar/enzimología , Sepsis/enzimología , Sepsis/metabolismo , Estilbenos/uso terapéutico , Animales , Líquido del Lavado Bronquioalveolar , Interleucina-6/sangre , Lesión Pulmonar/sangre , Ratones , Óxido Nítrico/metabolismo , Distribución Aleatoria , Sepsis/sangre , Factor de Transcripción ReIA/metabolismo , Factor de Necrosis Tumoral alfa/sangre
19.
Zhongguo Zhong Xi Yi Jie He Za Zhi ; 33(2): 225-8, 2013 Feb.
Artículo en Zh | MEDLINE | ID: mdl-23646479

RESUMEN

OBJECTIVE: To investigate the protective effects of polydatin on sepsis-induced acute liver injury (ALI) in mice, and to preliminarily study its mechanisms. METHODS: The sepsis model was established using cecal ligation and puncture (CLP).A sham-operation control group was also set up. Polydatin (50, 100, and 300 mg/kg, respectively) was administrated to mice 1 h before CLP. The survival and liver injury were evaluated subsequently per 6 h after CLP. The survived mice were scarified 24 h later. The serum and the liver tissue sample were collected. The serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were detected by colorimetric method. The content of tumor necrosis factor-alpha (TNF-alpha) was assayed by ELISA. The cyclooxygenase-2 (COX-2) expression in the liver tissue was detected by Western blot. The pathological changes of the hepatic tissue were analyzed by hematoxylin and eosin stain. RESULTS: The mortality of mice reached as high as 50% at 24 h after CLP. The biochemical indices and the pathological changes of the liver tissue showed obvious lesion. The success rate of modeling was 90%. Compared with the sham-operation control group, the serum ALT,AST activity, the TNF-alpha content, and the hepatic COX-2 protein expression markedly increased in the CLP group (P < 0.01). Polydatin improved the sepsis-induced mortality dose-dependently, inhibited increased ALT, AST activity and TNF-alpha, decreased the hepatic COX-2 protein expression, and attenuated the pathological injury of the liver (P < 0.05). CONCLUSION: Polydatin could effectively protect sepsis-induced ALI, which might be achieved possibly through inhibiting serum TNF-alpha production and hepatic COX-2 expression.


Asunto(s)
Glucósidos/farmacología , Sepsis/metabolismo , Estilbenos/farmacología , Alanina Transaminasa/sangre , Animales , Aspartato Aminotransferasas/sangre , Ciclooxigenasa 2/metabolismo , Modelos Animales de Enfermedad , Hígado/enzimología , Ratones , Ratones Endogámicos , Sepsis/patología , Factor de Necrosis Tumoral alfa/sangre
20.
J Intell ; 11(12)2023 Nov 30.
Artículo en Inglés | MEDLINE | ID: mdl-38132838

RESUMEN

This study investigated the relationship between executive functions and metacognition. Both constructs have been well-studied, but little research has focused on their connections. The goal of the current investigation was to increase the understanding of the relationship between metacognition and executive functions by assessing the relationships between metacognitive monitoring accuracy and the three component executive functions (updating, inhibition, and shifting) among college students. Metacognitive monitoring accuracy was measured using a knowledge monitoring accuracy (KMA) test. The three components of executive functions, updating, inhibition, and shifting were measured, respectively, using the ABCD updating task, the Stroop color-word interference test, and the letter-number task. The Tower of Hanoi task was used to measure the complex executive functions (inhibition and updating). Correlation and regression analyses were performed to examine the relationships. The results indicate that updating is the only component executive function that significantly correlated with metacognitive monitoring, suggesting that metacognition-specifically, metacognitive monitoring-is associated with at least one component of executive functioning.

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