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1.
Langmuir ; 39(15): 5323-5332, 2023 04 18.
Artículo en Inglés | MEDLINE | ID: mdl-37027513

RESUMEN

In this study, a porous carbonaceous adsorbent was prepared from sycamore flocs by pyrolysis method and K2CO3 activation. The effects of preparative conditions of the material on its adsorptive property were explored. The optimal material (SFB2-900) was obtained with a K2CO3/biochar mass ratio of 2:1 at an activation temperature of 900 °C, possessing a huge surface specific area (1651.27 m2/g). The largest adsorption capacity for ciprofloxacin on SFB2-900 was up to 430.25 mg/g. The adsorption behavior was well described by the pseudo-second-order kinetic model and the Langmuir isothermal model. Meanwhile, this process was spontaneous and exothermic. The obtained material showed excellent adsorption performance in the conditions of diverse pH range, ionic strength, and water quality of the solution. The optimum adsorption conditions (pH = 7.01, dosage = 0.6 g/L, and C0 = 52.94 mg/L) determined based on the response surface methodology were in accordance with the practical validation consequences. The good regeneration effect of SFB2-900 manifested that this material had great practical application potential. Combining the experimental results and density functional theory calculation results, the adsorption mechanisms mainly included pore filling, π-π EDA interactions, electrostatic interactions, and H-bonds. The material could be regarded as a novel and high-efficiency adsorbent for antibiotics. Additionally, these findings also provide reference for the reuse of waste biomass in water treatment.


Asunto(s)
Ciprofloxacina , Contaminantes Químicos del Agua , Ciprofloxacina/química , Adsorción , Contaminantes Químicos del Agua/química , Carbón Orgánico/química , Antibacterianos , Cinética
3.
Sensors (Basel) ; 23(24)2023 Dec 11.
Artículo en Inglés | MEDLINE | ID: mdl-38139613

RESUMEN

The engineering of thermo-optic effects has found broad applications in integrated photonic devices, facilitating efficient light manipulation to achieve various functionalities. Here, we perform both an experimental characterization and a theoretical analysis of these effects in integrated microring resonators made from high-index doped silica, which have had many applications in integrated photonics and nonlinear optics. By fitting the experimental results with theory, we obtain fundamental parameters that characterize their thermo-optic performance, including the thermo-optic coefficient, the efficiency of the optically induced thermo-optic process, and the thermal conductivity. The characteristics of these parameters are compared to those of other materials commonly used for integrated photonic platforms, such as silicon, silicon nitride, and silica. These results offer a comprehensive insight into the thermo-optic properties of doped silica-based devices. Understanding these properties is essential for efficiently controlling and engineering them in many practical applications.

4.
J Am Chem Soc ; 139(2): 619-622, 2017 01 18.
Artículo en Inglés | MEDLINE | ID: mdl-28013538

RESUMEN

K5Sb4 and K3Sb7 Zintl ion precursors react with Pd(PPh3)4 in ethylenediamine/toluene/PBu4+ solutions to give crystals of Sb@Pd12@Sb20n-/PBu4+ salts, where n = 3, 4. The clusters are structurally identical in the two charge states, with nearly perfect Ih point symmetry, and can be viewed as an Sb@Pd12 icosahedron centered inside of an Sb20 dodecahedron. The metric parameters suggest very weak Sb-Sb and Pd-Pd interactions with strong radial Sb-Pd bonds between the Sb20 and Pd12 shells. All-electron DFT analysis shows the 3- ion to be diamagnetic with Ih symmetry and a 1.33 eV HOMO-LUMO gap, whereas the 4- ion undergoes a Jahn-Teller distortion to an S = 1/2 D3d structure with a small 0.1 eV gap. The distortion is predicted to be small and is not discernible by crystallography. Laser desorption-ionization time-of-flight mass spectrometry (LDI-TOF MS) studies of the crystalline samples show intense parent Sb@Pd12@Sb20- ions (negative ion mode) and Sb@Pd12@Sb20+ (positive ion mode) along with series of Sb@Pd12-y@Sb20-x-/+ ions. Ni(cyclooctadiene)2 reacts with K3Sb7 in en/tol/Bu4PBr solvent mixtures to give black precipitates of Sb@Ni12@Sb20n- salts that give similar Sb@Ni12@Sb20-/+ parent ions and Sb@Ni12-y@Sb20-x-/+ degradation series in the respective LDI-TOF MS studies. The solid-state and gas-phase studies of the icosahedral Sb@M12@Sb20n-/n+ ions show that the clusters can exist in the -4, -3, -1, +1 (M = Pd) and +1, -1 (M = Ni) oxidation states. These multiple-charge-state clusters are reminiscent of redox-active fullerenes (e.g., C60n, where n = +1, 0, -1, -2, -3, -4, -5, -6).

5.
Acc Chem Res ; 49(10): 2336-2346, 2016 10 18.
Artículo en Inglés | MEDLINE | ID: mdl-27636834

RESUMEN

Conventional electrical energy storage (EES) electrodes, such as rechargeable batteries, are mostly based on composites of monolithic micrometer sized particles bound together with polymeric and conductive carbon additives and binders. The kinetic limitations of these monolithic chunks of material are inherently linked to their electrical properties, the kinetics of ion insertion through their interface and ion migration in and through the composite phase. Redox chemistry of nanostructured materials in EES systems offer vast gains in power and energy. Furthermore, due to their thin nature, ion and electron transport is dramatically increased, especially when thin heterogeneous conducting layers are employed synergistically. However, since the stability of the electrode material is dictated by the nature of the electrochemical reaction and the accompanying volumetric and interfacial changes from the perspective of overall system lifetime, research with nanostructured materials has shown often indefinite conclusions: in some cases, an increase in unwanted side-reactions due to the high surface area (bad). In other cases, results have shown significantly better handling of mechanical stress that results from lithiation/delithiation (good). Despite these mixed results, scientifically informed design of thin electrode materials, with carefully chosen architectures, is considered a promising route to address many limitations witnessed in EES systems by reducing and protecting electrodes from parasitic reactions, accommodating mechanical stress due to volumetric changes from electrochemical reactions, and optimizing charge carrier mobilities from both the "ionic" and "electronic" points of view. Furthermore, precise nanoscale control over the electrode structure can enable accurate measurement through advanced spectroscopy and microscopy techniques. This Account summarizes recent findings related to thin electrode materials synthesized by atomic layer deposition (ALD) and electrochemical deposition (ECD), including nanowires, nanotubes, and thin films. Throughout the Account, we will show how these techniques enabled us to synthesize electrodes of interest with precise control over the structure and composition of the material. We will illustrate and discuss how the electrochemical response of thin electrodes made by these techniques can facilitate new mechanisms for ion storage, mediate the interfacial electrochemical response of the electrode, and address issues related to electrode degradation over time. The effects of nanosizing materials and their electrochemical response will be mechanistically reviewed through two categories of ion storage: (1) pseudocapacitance and (2) ion insertion. Additionally, we will show how electrochemical processes that are more complicated because of accompanying volumetric changes and electrode degradation pathways can be mediated and controlled by application of thin functional materials on the electrochemically active interface; examples include conversion electrodes, reactive lithium metal anodes, and complex reactions in a Li/O2 cathode system. The goal of this Account is to illustrate how careful design of thin materials either as active electrodes or as mediating layers can facilitate desirable interfacial electrochemical activity and resolve or shed light on mechanistic limitations of electrochemical processes related to micrometer size particles currently used in energy storage electrodes.

6.
Nano Lett ; 16(9): 5875-82, 2016 09 14.
Artículo en Inglés | MEDLINE | ID: mdl-27518908

RESUMEN

Bismuth is a lithium-ion battery anode material that can operate at an equilibrium potential higher than graphite and provide a capacity twice as high as that of Li4Ti5O12, making it intrinsically free from lithium plating that may cause catastrophic battery failure. However, the potential of bismuth is hampered by its inferior cyclability (limited to tens of cycles). Here, we propose an "ion conductive solid-state matrix" approach to address this issue. By homogeneously confining bismuth nanoparticles in a solid-state γ-Li3PO4 matrix that is electrochemically formed in situ, the resulting composite anode exhibits a reversible capacity of 280 mA hours per gram (mA h/g) at a rate of 100 mA/g and a record cyclability among bismuth-based anodes up to 500 cycles with a capacity decay rate of merely 0.071% per cycle. We further show that full-cell batteries fabricated from this composite anode and commercial LiFePO4 cathode deliver a stable cell voltage of ∼2.5 V and remarkable energy efficiency up to 86.3%, on par with practical batteries (80-90%). This work paves a way for harnessing bismuth-based battery chemistry for the design of high capacity, safer lithium-ion batteries to meet demanding applications such as electric vehicles.

7.
Angew Chem Int Ed Engl ; 56(5): 1229-1233, 2017 01 24.
Artículo en Inglés | MEDLINE | ID: mdl-27936311

RESUMEN

Glucose is a key energy supplier and nutrient for tumor growth. Herein, inspired by the glucose oxidase (GOx)-assisted conversion of glucose into gluconic acid and toxic H2 O2 , a novel treatment paradigm of starving-like therapy is developed for significant tumor-killing effects, more effective than conventional starving therapy by only cutting off the energy supply. Furthermore, the generated acidic H2 O2 can oxidize l-Arginine (l-Arg) into NO for enhanced gas therapy. By using hollow mesoporous organosilica nanoparticle (HMON) as a biocompatible/biodegradable nanocarrier for the co-delivery of GOx and l-Arg, a novel glucose-responsive nanomedicine (l-Arg-HMON-GOx) has been for the first time constructed for synergistic cancer starving-like/gas therapy without the need of external excitation, which yields a remarkable H2 O2 -NO cooperative anticancer effect with minimal adverse effect.


Asunto(s)
Glucosa/metabolismo , Peróxido de Hidrógeno/metabolismo , Óxido Nítrico/metabolismo , Arginina/química , Línea Celular Tumoral , Proliferación Celular , Glucosa Oxidasa/metabolismo , Glucosa Oxidasa/uso terapéutico , Humanos , Nanomedicina , Nanopartículas/química , Nanopartículas/uso terapéutico , Neoplasias/metabolismo , Neoplasias/patología , Neoplasias/terapia , Oxidación-Reducción , Porosidad , Dióxido de Silicio/química
8.
Inorg Chem ; 55(9): 4344-53, 2016 05 02.
Artículo en Inglés | MEDLINE | ID: mdl-27064350

RESUMEN

The neutral homoleptic tris-bpy aluminum complexes Al((R)bpy)3, where R = tBu (1) or Me (2), have been synthesized from reactions between AlX precursors (X = Cl, Br) and neutral (R)bpy ligands through an aluminum disproportion process. The crystalline compounds have been characterized by single-crystal X-ray diffraction, electrochemical experiments, EPR, magnetic susceptibility, and density functional theory (DFT) studies. The collective data show that 1 and 2 contain Al(3+) metal centers coordinated by three bipyridine (bpy(•))(1-) monoanion radicals. Electrochemical studies show that six redox states are accessible from the neutral complexes, three oxidative and three reductive, that involve oxidation or reduction of the coordinated bpy ligands to give neutral (R)bpy or (R)bpy(2-) dianions, respectively. Magnetic susceptibility measurements (4-300 K) coupled with DFT studies show strong antiferromagnetic coupling of the three unpaired electrons located on the (R)bpy ligands to give S = (1)/2 ground states with low lying S = (3)/2 excited states that are populated above 110 K (1) and 80 K (2) in the solid-state. Complex 2 shows weak 3D magnetic interactions at 19 K, which is not observed in 1 or the related [Al(bpy)3] complex.

9.
Proc Natl Acad Sci U S A ; 110(44): 17892-7, 2013 Oct 29.
Artículo en Inglés | MEDLINE | ID: mdl-24114270

RESUMEN

Ten eleven translocation (TET) enzymes (TET1/TET2/TET3) and thymine DNA glycosylase (TDG) play crucial roles in early embryonic and germ cell development by mediating DNA demethylation. However, the molecular mechanisms that regulate TETs/TDG expression and their role in cellular differentiation, including that of the pancreas, are not known. Here, we report that (i) TET1/2/3 and TDG can be direct targets of the microRNA miR-26a, (ii) murine TETs, especially TET2 and TDG, are down-regulated in islets during postnatal differentiation, whereas miR-26a is up-regulated, (iii) changes in 5-hydroxymethylcytosine accompany changes in TET mRNA levels, (iv) these changes in mRNA and 5-hydroxymethylcytosine are also seen in an in vitro differentiation system initiated with FACS-sorted adult ductal progenitor-like cells, and (v) overexpression of miR-26a in mice increases postnatal islet cell number in vivo and endocrine/acinar colonies in vitro. These results establish a previously unknown link between miRNAs and TET expression levels, and suggest a potential role for miR-26a and TET family proteins in pancreatic cell differentiation.


Asunto(s)
Diferenciación Celular/fisiología , Proteínas de Unión al ADN/metabolismo , Epigénesis Genética/fisiología , Regulación del Desarrollo de la Expresión Génica/fisiología , Islotes Pancreáticos/fisiología , MicroARNs/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Timina ADN Glicosilasa/metabolismo , 5-Metilcitosina/análogos & derivados , Animales , Citosina/análogos & derivados , Dioxigenasas , Citometría de Flujo , Islotes Pancreáticos/enzimología , Luciferasas , Ratones , Ratones Transgénicos , Microfluídica , Reacción en Cadena en Tiempo Real de la Polimerasa
10.
Angew Chem Int Ed Engl ; 55(34): 9898-901, 2016 08 16.
Artículo en Inglés | MEDLINE | ID: mdl-27417442

RESUMEN

Aluminum metal is a promising anode material for next generation rechargeable batteries owing to its abundance, potentially dendrite-free deposition, and high capacity. The rechargeable aluminum/sulfur (Al/S) battery is of great interest owing to its high energy density (1340 Wh kg(-1) ) and low cost. However, Al/S chemistry suffers poor reversibility owing to the difficulty of oxidizing AlSx . Herein, we demonstrate the first reversible Al/S battery in ionic-liquid electrolyte with an activated carbon cloth/sulfur composite cathode. Electrochemical, spectroscopic, and microscopic results suggest that sulfur undergoes a solid-state conversion reaction in the electrolyte. Kinetics analysis identifies that the slow solid-state sulfur conversion reaction causes large voltage hysteresis and limits the energy efficiency of the system.

11.
Phys Chem Chem Phys ; 17(23): 15173-80, 2015 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-25990197

RESUMEN

A wide range of metal oxides have been studied as pseudocapitors, with the goal of achieving higher power than traditional batteries and higher energy than traditional capacitors. However, most metal oxides have relatively low conductivity, and the few exceptions, like RuO2, are prohibitively expensive. Mixed metal oxides provided an opportunity to incorporate small amounts of expensive materials to enhance the performance of a less expensive, poorer performing material. Here, by homogeneously co-depositing a small amount of energy dense and conductive RuO2 into MnO2 nanowires, we demonstrate an improvement in specific capacitance. Importantly, we also demonstrate that this improvement is not primarily provided by redox activity of RuO2, but rather by improvement of the composite conductivity. A series of RuO2-MnO2 composite nanowires with different RuO2 loading percentages have been synthesized by performing co-electrodeposition in a porous alumina template. The structure of these RuO2-MnO2 nanowires is characterized by TEM and SEM. EDS mapping shows that RuO2 is well distributed in MnO2 matrix nanowires. The chemical constituents and the phase of these composite nanowires are confirmed by X-ray photoelectron and Raman spectroscopy. The amount of RuO2 is controlled by varying the concentrations of RuCl3 and MnAc2 in the deposition solution. The precise masses of MnO2 and RuO2 are determined by ICP-AES elemental analysis. MnO2 nanowires with 6.70 wt% RuO2 demonstrate a specific capacitance of 302 F g(-1) at 20 mV s(-1), compared to 210 F g(-1) for pristine MnO2 nanowires. Investigation of the RuO2 loading amount effect was conducted by electrochemical impedance spectroscopy (EIS) and deconvolution of capacitances, using methods previously reported by both Dunn and Transsiti. The RuO2-MnO2 nanowires studied here demonstrate a simple, straighforward method to overcome the intrinsically poor conductivity of MnO2, and clarify the source of RuO2's contribution to the improved performance.

12.
Phys Chem Chem Phys ; 16(24): 12332-40, 2014 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-24824847

RESUMEN

A redox exchange mechanism between potassium perruthenate (KRuO4) and the functional groups of selected polymers is used here to induce RuO2 into and onto conductive polymer nanowires by simply soaking the polymer nanowire arrays in KRuO4 solution. Conductive polymer nanowire arrays of polypyrrole (PPY) and poly(3,4-ethylenedioxythiophene) (PEDOT) were studied in this work. SEM and TEM results show that the RuO2 material was distributed differently in the PPY and PEDOT nanowire matrices. Energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy were used to confirm the dispersion and formation of RuO2 materials in these polymer nanowires. Cyclic voltammetry and galvanostatic charge-discharge experiments were used to characterize their electrochemical performance. RuO2-polymer samples prepared with a 6 min soaking time in 10 mM KRuO4 solution show a high specific capacitance of 371 F g(-1) and 500 F g(-1) for PEDOT-based and PPY-based composite nanowires, respectively. This is attributed to the high exposure area of the conductive RuO2 and the good conductivity of the polymer matrix. This work demonstrates a simple method to synthesize heterogeneous polymer based-materials through the redox reaction between conductive polymers and high oxidation state transition metal oxide ions. Different heterogeneous nanocomposites were obtained depending on the polymer properties, and high energy storage performance of the metal oxides can be achieved within these heterogeneous nanostructures.

13.
Adv Mater ; : e2403659, 2024 Jun 06.
Artículo en Inglés | MEDLINE | ID: mdl-38843445

RESUMEN

On-chip integration of 2D materials with unique structures and properties endow integrated devices with new functionalities and improved performance. With high flexibility in ways to modify its properties and compatibility with integrated platforms, graphene oxide (GO) is an exceptionally attractive 2D material for hybrid integrated photonic chips. Here, by harnessing unique property changes induced by photothermal effects in 2D GO films, novel functionalities beyond the capability of photonic integrated circuits are demonstrated. These include all-optical control and tuning, optical power limiting, and nonreciprocal light transmission. The 2D layered GO films are integrated onto photonic chips with precise control of their thickness and size. Benefitting from the broadband optical response of 2D GO films, all three functionalities feature a very wide operational optical bandwidth. By fitting the experimental results with theory, the changes in GO film properties induced by the photothermal effects are analyzed, revealing interesting insights about the physics of 2D GO films. These results highlight the versatility of 2D GO films in implementing new functions for integrated photonic devices for a wide range of applications.

14.
Phys Chem Chem Phys ; 15(21): 7976-93, 2013 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-23624670

RESUMEN

A review of electrochemically synthesized nanomaterials with different controllable architectures for electrochemical energy storage devices is shown. It is demonstrated that these nano-architectures can be created either by electrodeposition or by the electrochemical transformation of materials. Electrochemical synthesis is presented here as it provides intimate contact between the electrode and current collector and also promotes an electronic pathway for all materials to be connected to the circuit. Although still in their infancy, electrosynthesized nano-architectures show promise to be used in future electrochemical energy storage devices as utilization of this method bypasses the need for bulky conductive additives and electrochemically inactive binders. Furthermore, electrochemical transformations can be used to create additional architectural features or change the chemical make-up of the electrode. This review is meant to show the creativity of current science when it comes to these nano-architectured electrodes. It is organized by technique used for synthesis including hard template, soft template, and template-free synthesis along with electrochemical transformation techniques.

15.
Pharmaceutics ; 15(12)2023 Nov 22.
Artículo en Inglés | MEDLINE | ID: mdl-38139997

RESUMEN

Parkinson's Disease (PD) is a neurodegenerative disease characterized by the progressive loss of dopaminergic neurons of the substantia nigra pars compacta with a reduction in dopamine concentration in the striatum. It is a substantial loss of dopaminergic neurons that is responsible for the classic triad of PD symptoms, i.e., resting tremor, muscular rigidity, and bradykinesia. Several current therapies for PD may only offer symptomatic relief and do not address the underlying neurodegeneration of PD. The recent developments in cellular reprogramming have enabled the development of previously unachievable cell therapies and patient-specific modeling of PD through Induced Pluripotent Stem Cells (iPSCs). iPSCs possess the inherent capacity for pluripotency, allowing for their directed differentiation into diverse cell lineages, such as dopaminergic neurons, thus offering a promising avenue for addressing the issue of neurodegeneration within the context of PD. This narrative review provides a comprehensive overview of the effects of dopamine on PD patients, illustrates the versatility of iPSCs and their regenerative abilities, and examines the benefits of using iPSC treatment for PD as opposed to current therapeutic measures. In means of providing a treatment approach that reinforces the long-term survival of the transplanted neurons, the review covers three supplementary avenues to reinforce the potential of iPSCs.

16.
Cell Death Dis ; 13(1): 48, 2022 01 10.
Artículo en Inglés | MEDLINE | ID: mdl-35013124

RESUMEN

Deposition of amyloid-ß (Aß) in the brain is one of the important histopathological features of Alzheimer's disease (AD). Previously, we reported a correlation between cell adhesion molecule L1 (L1) expression and the occurrence of AD, but its relationship was unclear. Here, we report that the expression of L1 and a 70 kDa cleavage product of L1 (L1-70) was reduced in the hippocampus of AD (APPswe) mice. Interestingly, upregulation of L1-70 expression in the hippocampus of 18-month-old APPswe mice, by parabiosis involving the joining of the circulatory system of an 18-month-old APPswe mouse with a 2-month-old wild-type C57BL/6 mouse, reduced amyloid plaque deposition. Furthermore, the reduction was accompanied by the appearance of a high number of activated microglia. Mechanistically, we observed that L1-70 could combine with topoisomerase 1 (Top1) to form a complex, L1-70/Top1, that was able to regulate expression of macrophage migration inhibitory factor (MIF), resulting in the activation of microglia and reduction of Aß plaques. Also, transforming growth factor ß1 (TGFß-1) transferred from the blood of young wild-type C57BL/6 mice to the aged AD mice, was identified as a circulating factor that induces full-length L1 and L1-70 expression. All together, these findings suggest that L1-70 contributes to the clearance of Aß in AD, thereby adding a novel perspective in understanding AD pathogenesis.


Asunto(s)
Enfermedad de Alzheimer/prevención & control , Molécula L1 de Adhesión de Célula Nerviosa/metabolismo , Fragmentos de Péptidos/metabolismo , Placa Amiloide/prevención & control , Envejecimiento , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/patología , Péptidos beta-Amiloides/metabolismo , Animales , ADN-Topoisomerasas de Tipo I/metabolismo , Modelos Animales de Enfermedad , Hipocampo/metabolismo , Hipocampo/patología , Oxidorreductasas Intramoleculares/metabolismo , Factores Inhibidores de la Migración de Macrófagos/metabolismo , Ratones , Microglía/metabolismo , Neuronas/metabolismo , Parabiosis , Placa Amiloide/metabolismo , Placa Amiloide/patología , Factor de Crecimiento Transformador beta1/metabolismo
17.
Bioresour Technol ; 350: 126884, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35219786

RESUMEN

In this study, sycamore flocs (SF), which caused environmental and health problems, were utilized to prepare biochar. SFB2-900 obtained under the conditions of activation agent K2CO3, pyrolysis temperature 900℃ and m(K2CO3):m(BC) 2 had the strongest adsorption capacity (730 mg/g) for oxytetracycline hydrochloride (OTC-HCl). The pseudo-second-order kinetic model and Langmuir model described the adsorption kinetics and isotherms best. SFB2-900 exhibited high OTC-HCl adsorption capacity in both higher ionic strength and wide pH range. The theoretical simulation indicated that the closest interaction distance between OTC-HCl and SFB2-900 was 2.44 Å via π-π stacking configuration. Pore filling, π-π electron donor acceptor (EDA) interaction, H-bonding and electrostatic interactions were also involved in the process of OTC-HCl removal. SFB2-900 showed great removal efficiency for OTC-HCl in different water matrices and good regeneration ability. This study solved the problems caused by SF, realized waste biomass recycling, and achieved preparing high-efficient adsorbent for antibiotic.


Asunto(s)
Oxitetraciclina , Contaminantes Químicos del Agua , Adsorción , Carbón Orgánico , Cinética , Oxitetraciclina/análisis , Contaminantes Químicos del Agua/análisis
18.
Am J Transl Res ; 14(5): 3360-3371, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35702111

RESUMEN

PURPOSE: Apoptosis induced by excessive endoplasmic reticulum (ER) stress is accompanied by the occurrence and progression of myocardial ischemia/reperfusion (I/R) injury. COX-2 is also known to affect the development of I/R damage in myocardium. However, the interaction between COX-2 and ER stress in aggravating myocardial I/R lesion is not well characterized. Therefore, the purpose of our research was to explore the interaction between COX-2 and ER stress on myocardial apoptosis. METHODS: The left anterior descending (LAD) coronary artery was ligatured with a 6-0# suture for 0.5 hours and subsequently subjected to reperfusion for 3 hours to simulate myocardial I/R in mice. Oxygen glucose deprivation/reoxygenation (OGD/R) was performed on H9c2 cells to construct an in vitro model of this experiment. NS398 (COX-2 specific inhibitor) and Salubrinal (Sal, ER stress inhibitor) were administered to assess the function of COX-2 and ER stress in myocardial I/R impairment. CCK-8 assay was used to evaluate the viability of H9c2 cells under different treatment conditions. TUNEL and Hoechst staining were used to detect the occurrence of apoptosis. Infarct area/area at risk and Hematoxylin-eosin stained sections were assessed after I/R. Protein expressions of glucose-regulated protein 78 (GRP78), COX-2, phosphorylation of eukaryotic translation initiation factor 2 alpha (p-eIF2α), CCAAT/enhancer-binding protein homologous protein (CHOP), and Cleaved caspase 3 in the myocardium were examined using Western blotting. Changes in Cleaved caspase 3 expression in myocardial slices were measured by immunohistochemistry. RESULTS: Sal or NS398 partly reduced I/R-induced damage as testified by the apparent decrease in infarct size after I/R and reduced cell viability following OGD/R. Sal distinctly increased p-eIF2α, but caused decreased expression of COX-2, Cleaved caspase 3, and ER stress-associated proteins after I/R, suggesting that Sal effectively inhibited ER stress, apoptosis, and COX-2. Pretreatment with NS398 blocked I/R or OGD/R-induced upregulation of COX-2, Cleaved caspase 3, and ER stress-related marker proteins. CONCLUSIONS: Interaction of COX-2 and ER stress regulates apoptosis and contributes to Myocardial lesion induced by I/R.

19.
Front Genet ; 13: 946524, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36159993

RESUMEN

Background: The mechanisms underlying myocardial ischemia/reperfusion (I/R) injury are not fully understood. This study aims to explore key candidate genes and potential therapeutic targets for treatment of myocardial I/R injury. Methods: The transcriptional profiles of ventricular myocardium during cardiac arrest, ischemia, and reperfusion were obtained from the Gene Expression Omnibus database. Based on the transcriptional data of GSE6381, functional pathway and process enrichment analyses, protein-protein interaction network, and gene set enrichment analyses were conducted. In the animal experiments, we established the myocardial I/R injury model in mice. We validated the mRNA and protein expression of the key genes using the qPCR and western blots. We further assessed the expression and localization of CCL21 and its receptors using immunofluorescence staining experiments. Results: The microarray analyses identified five key genes (CCL21, XCR1, CXCL13, EDN1, and CASR). Myocardial I/R process in mice resulted in significant myocardial infraction, histological damage, and myocardial apoptosis. The results of qPCR and western blots showed that the expression of CCL21 and CXCL13 were increased following myocardial I/R injury in mice. Furthermore, the immunofluorescence staining results revealed that the expression of GPR174/CCR7 (CCL21 receptors), but not CXCR5 (CXCL13 receptor), was elevated following myocardial I/R injury. Moreover, the activated CCL21-GPR174/CCR7 signaling was located on the cardiac fibroblasts of the myocardium with I/R injury. Conclusion: This study revealed several key factors underlying myocardial I/R injury. Of these, the activation of CCL21-GPR174/CCR7 signaling on cardiac fibroblasts was highlighted, which provides potential therapeutic targets for cardioprotection.

20.
Front Pharmacol ; 13: 782466, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35873574

RESUMEN

Ischemia-reperfusion (I/R) injury is a serious clinical pathology associated with acute kidney injury (AKI). Ferroptosis is non-apoptotic cell death that is known to contribute to renal I/R injury. Dexmedetomidine (Dex) has been shown to exert anti-inflammatory and organ protective effects. This study aimed to investigate the detailed molecular mechanism of Dex protects kidneys against I/R injury through inhibiting ferroptosis. We established the I/R-induced renal injury model in mice, and OGD/R induced HEK293T cells damage in vitro. RNA-seq analysis was performed for identifying the potential therapeutic targets. RNA-seq analysis for differentially expressed genes (DEGs) reported Acyl-CoA synthetase long-chain family member 4 (ACSL4) related to ferroptosis and inflammation in I/R mice renal, which was validated in rodent renal. Liproxstatin-1, the specific small-molecule inhibitor of ferroptosis, significantly attenuated ferroptosis-mediated renal I/R injury with decreased LPO, MDA, and LDH levels, and increased GSH level. Inhibiting the activity of ACSL4 by the Rosiglitazone (ROSI) resulted in the decreased ferroptosis and inflammation, as well as reduced renal tissue damage, with decreasing LPO, MDA and LDH level, increasing GSH level, reducing COX2 and increasing GPx4 protein expression, and suppressing the TNF-α mRNA and IL-6 mRNA levels. Dex as a α2-adrenergic receptor (α2-AR) agonist performed renal protective effects against I/R-induced injury. Our results also revealed that Dex administration mitigated tissue damage, inhibited ferroptosis, and downregulated inflammation response following renal I/R injury, which were associated with the suppression of ACSL4. In addition, ACSL4 overexpression abolishes Dex-mediated protective effects on OGD/R induced ferroptosis and inflammation in HEK293T cells, and promotion of ACSL4 expression by α2-AR inhibitor significantly reversed the effects on the protective role of Dex. This present study indicated that the Dex attenuates ferroptosis-mediated renal I/R injury and inflammation by inhibiting ACSL4 via α2-AR.

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