Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.028
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Chemosphere ; 238: 124671, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31473527

RESUMO

In this study, Fe/Cu, Fe/Al/Cu, Fe/Cu/C and Fe/Al/Cu/C internal electrolysis systems (IESs) were constructed and used to treat methylene blue dye (MB) wastewater. The effects of filler mass ratio, filler dosage, solution pH, reaction time and reaction temperature on COD removal were discussed, while the kinetics, thermodynamics and mechanism of COD removal were also investigated. The results showed that when the COD removal rates were basically the same, the reaction times of Fe/Al/Cu, Fe/Cu/C and Fe/Al/Cu/C IESs were shorter, and the filler dosages were lower. For the four systems, the appropriate pH was around 5, while the suitable reaction temperature was in the range of 20-25 °C. The COD removals of these four IESs were generally greater than 90%. The COD removal processes of the four systems could be better described by the improved pseudo-second-kinetic model, and the liquid film diffusion was the rate-controlling step. Moreover, the COD removal was a spontaneous and endothermic process. MB was degraded into inorganic substances in four steps. In addition, the FTIR characterization of the fillers before and after reaction suggests the four IESs have good stability.

2.
J Med Chem ; 2019 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-31724854

RESUMO

Nicotinamide N-methyltransferase (NNMT) catalyzes the methyl transfer from cofactor S-adenosylmethionine (SAM) to nicotinamide and other pyridine-containing compounds. NNMT is an important regulator for nicotinamide metabolism and methylation potential. Aberrant expression levels of NNMT have been implicated in cancer, metabolic and neurodegenerative diseases, which makes NNMT a potential therapeutic target. Therefore, potent and selective NNMT inhibitors can serve as valuable tools to investigate the roles of NNMT in its mediated diseases. Here, we applied a rational strategy to design and synthesize the tight-binding bisubstrate inhibitor LL320 through a novel propargyl linker. LL320 demonstrates a Ki value of 1.6±0.3 nM, which is the most potent inhibitor to date. The co-crystal structure of LL320 confirms its interaction with both the substrate and cofactor binding sites on NNMT. Importantly, this is the first example of using propargyl linker to construct potent methyltransferase inhibitors, which will expand our understanding of the transition state of methyl transfer.

3.
J Biomed Nanotechnol ; 15(12): 2332-2350, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31748015

RESUMO

Developing basement membranes (BMs) substitute remains major problem for constructing functional tissue engineered skin because of its complex structure and multifunction of regulating cellular behavior. Herein, a stable electrospinning method was employed to generate a biomimetic model of natural BMs based on novel scaffold electrospun from Poly(ɛ-caprolactone) (PCL) and cellulose acetate (CA) incorporated with chitosan (CS). The morphology, structure, surface hydrophilicity, roughness and mechanical tensile strength of prepared monolayer and tri-layered scaffold were comprehensively compared. Besides, co-culture system via seeding keratinocytes (Kcs) and fibroblasts (Fbs) on opposite side of tri-layered scaffold revealed more effective segregation of both cell types within the central nanofibrous barrier together with enhanced cell attachment and proliferation than that on the monolayer scaffold. Moreover, the deposition of type VII collagen and laminin-5 was examined in comparison with normal skin BMs. Furthermore, the histological studies revealed characteristics of reconstructing BM zone at the junction of dermis-epidermis after in vivo implantation for 2 weeks, and wound healing while the seeded cells interacted with the endogenous cells. Additionally, the expression of active integrin ß1 and phosphorylated focal adhesion kinase (FAK) was promoted with treatment of tri-layered scaffold. This study stressed that this tri-layer scaffold might provoke biomimetic responses of Kcs and Fbs and thus be applied for future development of BMs containing tissues.


Assuntos
Biomimética , Nanofibras , Membrana Basal , Proliferação de Células , Poliésteres , Engenharia Tecidual , Tecidos Suporte
4.
Int J Biol Macromol ; 2019 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-31730974

RESUMO

Yam (Dioscorea spp.), known as an edible and medicinal tuber crop in China, has been used historically for the treatment of diabetes, diarrhea, asthma, and other ailments in traditional Chinese medicine. Moreover, it has been consumed as starchy food for thousands of years in China. Modern phytochemistry and pharmacological experiments have been proved that non-starch polysaccharide is one of the main bioactive substances of yam. Many studies have been focused on the isolation and identification of polysaccharides and their bioactivities of Chinese yam. However, due to the difference in the variety of raw materials and the method of polysaccharides extracting, the structure and biological activity of the obtained polysaccharides also differ. It has been demonstrated that Chinese yam polysaccharide has various important biological activities, such as hypoglycemia, immunomodulatory, antioxidant, and antitumor activities. This paper is aimed at summarizing previous and current references of the isolation processes, structural features and bioactivities of yam polysaccharides. The review will serve as a useful reference material for further investigation and application of yam polysaccharides in functional foods and medicine fields.

5.
Cancer Lett ; 2019 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-31765738

RESUMO

The bromodomain and extra-terminal domain protein BRD4 has been recognized as a key oncogenic driver and a druggable target against cancer. However, these BRD4 inhibitors as monotherapy were moderate in efficacy in preclinical models. Here we utilized a small-scale drug synergy screen that combined the BRD4 inhibitor (JQ1) with 8 epigenetic or transcriptional targeted chemicals and identified THZ1 (a CDK7 inhibitor) acting synergistically with JQ1 against head neck squamous cell carcinoma (HNSCC). Combinational JQ1 and THZ1 treatment impaired cell proliferation, induced apoptosis and senescence, which were largely recapitulated by dual BRD4 and CDK7 knockdown. Combinational treatment inhibited tumor growth and progression in 4NQO-induced HNSCC and xenograft animal models. RNA-sequencing analyses identified hundreds of differentially expressed genes modulated by JQ1 and THZ1, which were significantly enriched in categories including cell cycle and apoptosis. Mechanistically, combinational treatment reduced H3K27ac enrichment in the super-enhancer region of YAP1, which inactivated its transcription and in turn induced anti-proliferative and pro-apoptotic effects. Combined BRD4 and CDK7 upregulation associated with worst prognosis in HNSCC patients. Collectively, our findings reveal a novel therapeutic strategy of pharmacological inhibitions of BRD4 and CDK7 against HNSCC.

6.
Artigo em Inglês | MEDLINE | ID: mdl-31679785

RESUMO

Electrocatalytic water splitting using bi-functional catalysts is one of the most promising approaches for clean hydrogen fuel production. To address shortcomings of the existing catalysts, here we develop a new bi-functional catalysts cobalt-based nano-architecture with ordered, Ni-doped two-dimensional (2D) defect-rich nanosheets. Innovative combination of doping, annealing, and sulfidation is developed to fabricate the hierarchical porous metal sulfide (denoted as Ni-Co-S) nanosheets arrays (HPNA) directly on conductive carbon cloth (CC). Owing to the unique architecture with the specific surface area and porous structure, short ion diffusion paths, the Ni-Co-S HPNA exhibits excellent electrocatalytic activitiy for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline solution, featuring low overpotentials of 110 and 270 mV at a current density of 10 mA cm-2, respectively. The excellent catalytic performance is attributed to the unique porous structure, abundant active sites and efficient mass transport. More importantly, when the Ni-Co-S HPNA serves as both the anode and cathode, it achieves a 1.62 V at 10 mA cm-2 and remains stable over 12 h of the overall water splitting process. This work opens new avenues for rational design of high-efficiency and stable bifunctional electrocatalysts for water electrolysis and a broader range of clean energy and sustainable chemistry applications.

7.
Cleft Palate Craniofac J ; : 1055665619887628, 2019 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-31726862

RESUMO

INTRODUCTION: Facial normalcy, as measured with 2-dimensional or 3-dimensional photographs, has been documented in the healthy pediatric population. However, static images convey far from a complete representation of an individual's daily interactions with peers. Craniofacial surgery induces changes to soft or osseous tissues and thereby affects dynamic facial expression. To-date, there has not been rigorous, dynamic quantification of normal facial expression. In this study, we used 4-dimensional (4D) imaging to assess the facial expression of healthy children to provide a normative reference point for craniofacial surgeons. METHODS: A total of 36 healthy pediatric volunteers underwent 4D video recordings while performing a maximal voluntary smile. A face template containing 884 landmarks was registered and tracked throughout the videos using Dimensional Imaging software. Participants were divided into 2 smile groups: open-lip smile and closed-lip smile. Kinematic analysis of smiles was calculated for every landmark from its position in the resting frame to its terminal displacement. RESULTS: Composite smiles and Euclidean distance maps were generated displaying areas of greatest displacement near the oral commissures. There was significant difference between closed-lip and open-lip groups in regions of eyes and cheeks. In addition, the open-lip smile group demonstrated significantly greater displacement in the oral commissure on the left side compared to the right (P < .05); whereas, in the closed-lip group, the eyes and cheeks moved significantly more on the right side. CONCLUSION: This study presents an innovative method that can be used to evaluate facial expressions to help craniofacial surgeons restore functional movement in patients with facial anomalies.

8.
Sci Rep ; 9(1): 16969, 2019 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-31740691

RESUMO

We present a systematic study of surface band bending in Ga-polar n-GaN with different Si doping concentrations by angular dependent X-ray photoelectron spectroscopy (ADXPS). The binding energies of Ga 3d and N 1 s core levels in n-GaN films increase with increasing the emission angle, i. e., the probing depth, suggesting an upward surface band bending. By fitting the Ga 3d core level spectra at different emission angles and considering the integrated effect of electrostatic potential, the core level energy at the topmost surface layer is well corrected, therefore, the surface band bending is precisely evaluated. For moderately doped GaN, the electrostatic potential can be reflected by the simply linear potential approximation. However, for highly doped GaN samples, in which the photoelectron depth is comparable to the width of the space charge region, quadratic depletion approximation was used for the electrostatic potential to better understand the surface band bending effect. Our work improves the knowledge of surface band bending determination by ADXPS and also paves the way for studying the band bending effect in the interface of GaN based heterostructures.

9.
Artigo em Inglês | MEDLINE | ID: mdl-31742379

RESUMO

Graphene oxide (GO) with a two-dimensional lamellar structure and single-atom thickness has exhibited advantages in water purification by stacking to a continuous membrane. However, a proper method to further increase the separation property of the GO membrane is still urgently needed. Besides, damage to the membrane during the full-scale application processes and the resulted consequential loss are prevalent problems need to be solved. Here, a hierarchically assembled GO composite membrane was developed that can achieve high-efficiency water purification performance and self-healing property via the synergistic effect of the metal-organic framework (MOF) and the coated hydrophilic layer of chitosan. The intercalated MOF effectively expanded the channel space of GO and endowed the channels with molecular-sieving property. Meanwhile, the coated chitosan layer can selectively adsorb water and achieve self-healing through the cross-linking reaction. The prepared GO composite membrane shows largely improved water flux (14.62 L m-2 h-1 bar-1), increased 344% than the water flux of the GO membrane, high rejection ratio (>99% for dyes), and good antifouling performance. In addition, the damaged GO composite membrane can recover its water flux (95%) and rejection ratio (96%) through a facile self-healing process.

10.
Reproduction ; 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31770100

RESUMO

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in reproductive-age women usually accompanied by lipid metabolic disorders. However, it remains unknown whether arachidonic acid (AA) and its metabolites in follicular fluid (FF) were altered in PCOS patients. This study was intended to measure the levels of AA and its metabolites in the FF of non-obese PCOS patients that underwent in vitro fertilization (IVF) and to explore the possible causes of the alterations. Thirty-nine non-obese women with PCOS and thirty non-obese women without PCOS were enrolled. AA and its metabolites were measured by liquid chromatography-mass spectrometry. The levels of AA metabolites generated via cyclooxygenase-2 (COX-2) pathway and cytochrome P450 epoxygenase pathway but not lipoxygenase (LOX) pathway were significantly higher in the FF of PCOS patients. The metabolites generated via COX-2 pathway were significantly correlated with levels of testosterone and fasting insulin in serum. The in vitro study further demonstrated that insulin but not testosterone could promote the IL-1ß and hCG-induced COX-2 expression and Prostaglandin E2 (PGE2) secretion in primary human granulosa cells. In conclusion, there was an elevation in AA metabolites in FF of PCOS patients. Insulin played a pivotal role in the increased AA metabolites generated via COX-2, which could be interpreted as another novel molecular pathophysiological mechanism of PCOS.

11.
Artigo em Inglês | MEDLINE | ID: mdl-31651801

RESUMO

BACKGROUND: Post-ERCP pancreatitis (PEP) is reported to occur in up to 11% of pediatric patients. To date, no study has prospectively evaluated an intervention to prevent PEP in children. It is unclear if such a study is even feasible. OBJECTIVE: To evaluate the feasibility of studying IV Ibuprofen for PEP prevention in the pediatric population. METHODS: This was a prospective randomized double-blind placebo-controlled feasibility study. Patients < 19 years of age undergoing ERCP were randomized to receive 10 mg/kg IV Ibuprofen (max of 800 mg) or placebo (saline) at the time of ERCP. The primary outcome was PEP. Secondary outcomes included post-ERCP related bleeding, rates of other procedural and medication related adverse events. RESULTS: 58 patients were randomized and received either IV Ibuprofen or placebo. Pre-procedure and procedure related factors were not significantly different between the groups except that patients in the placebo group tended to weigh less (48.7 kg vs 63.7 kg, p = 0.03). There were 7 episodes of PEP (12%). PEP was less frequently identified in the Ibuprofen group than the control group (7% vs. 17%), but this was not statistically significant (p = 0.42). Mean post-procedural abdominal pain scores were significantly lower in the IV Ibuprofen group than the control group (1.1 vs 3.1, p = 0.01) and the number of patients who had increased abdominal pain after the procedure was significantly lower in Ibuprofen group than the control group (3% vs. 38%, p = 0.002). There were no significant differences in procedure related or drug related adverse events. CONCLUSIONS: Post-procedural pain scores and the number of patients who had increased abdominal pain after the procedure were significantly lower in the IV Ibuprofen group. The current study provides encouraging, but only very weak evidence that IV ibuprofen decreases PEP in children. Power analysis suggests that a small handful of high-volume pediatric centers would be able to perform an adequate clinical trial in a reasonable time frame. Focusing on all cause post-procedural pain (PEP and non-PEP) may allow for a more efficiency study design and be just as clinically relevant.

12.
Fish Shellfish Immunol ; 95: 35-43, 2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31610292

RESUMO

In mammal, CYP1A has attracted special attention due to its important roles in the oxidative metabolism. In fish, the researches on CYP1A are more focus on its roles in pollution in water environments, but the immune function is unclear. In the study, CiCYP1A gene was cloned from grass carp (Ctenopharyngodon idella). Tissue distribution exhibited an overwhelmingly high basal expression levels in the liver. After GCRV infection, CiCYP1A showed a potent response, indicating CiCYP1A was involved in GCRV-induced immunity. Subcellular localisation showed CiCYP1A was distributed in the cytoplasm. Besides, dual-luciferase activity assays revealed CYP1A was relevant for IFN-I signaling pathway modulation, furthermore, overexpressed CYP1A potently suppressed the mRNA expression of IRF3 and IFN-I but not IRF7. The results provide new sights into exploring immune function of CiCYP1A in teleosts.

13.
Int J Mol Sci ; 20(19)2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31575032

RESUMO

Transmembrane Ca2+ influx is essential to the proper functioning of the central clock in the suprachiasmatic nucleus (SCN). In the rat SCN neurons, the clearance of somatic Ca2+ following depolarization-induced Ca2+ transients involves Ca2+ extrusion via Na+/Ca2+ exchanger (NCX) and mitochondrial Ca2+ buffering. Here we show an important role of intracellular Na+ in the regulation of [Ca2+]i in these neurons. The effect of Na+ loading on [Ca2+]i was determined with the Na+ ionophore monensin and the cardiac glycoside ouabain to block Na+/K+-ATPase (NKA). Ratiometric Na+ and Ca2+ imaging was used to measure the change in [Na+]i and [Ca2+]i, and cell-attached recordings to investigate the effects of monensin and ouabain on spontaneous firing. Our results show that in spite of opposite effects on spontaneous firing and basal [Ca2+], both monensin and ouabain induced Na+ loading, and increased the peak amplitude, slowed the fast decay rate, and enhanced the slow decay phase of 20 mM K+-evoked Ca2+ transients. Furthermore, both ouabain and monensin preferentially enhanced nimodipine-insensitive Ca2+ transients. Together, our results indicate that in the SCN neurons the NKA plays an important role in regulating [Ca2+]i, in particular, associated with nimodipine-insensitive Ca2+ channels.

14.
BMC Endocr Disord ; 19(1): 108, 2019 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-31651303

RESUMO

BACKGROUND: The adipokine adipsin contributes to insulin resistance (IR), inflammation, and obesity, which are all regarded as high-risk factors for mild cognitive impairment (MCI) in patients with type 2 diabetes mellitus. This research aimed to uncover the role of adipsin in Chinese type 2 diabetes mellitus (T2DM) population with early cognitive dysfunction and determine whether adipsin contributes to diabetic MCI caused by IR. METHODS: In our study, 126 patients with T2DM were enrolled. The Montreal Cognitive Assessment (MoCA) was used to assess cognitive impairment. Demographic data and neuropsychological test results were evaluated. Plasma adipsin level was measured by enzyme-linked immunosorbent assay. RESULTS: The MCI group (n = 57) presented higher plasma adipsin levels compared with the healthy controls (p = 0.018). After adjustment for educational attainment, and age, begative correlations were found between plasma adipsin levels and MoCA, Mini Mental State Exam, and Verbal Fluency Test scores(r = - 0.640, p < 0.001; r = - 0.612, p < 0.001; r = - 0.288, p = 0.035; respectively). Correlation analysis demonstrated that adipsin levels were significantly positively correlated with fasting C-peptide; homeostasis model of assessment for insulin resistance (HOMA-IR) (r = 0.368, p < 0.001; r = 0.494, p < 0.001; respectively). Multivariable regression analysis further indicated that high plasma adipsin level was a significant independent determinant of MCI in the Chinese population withT2DM (p = 0.017). CONCLUSIONS: Elevated plasma adipsin level was associated with MCI in Chinese T2DM patients. Further large-scale studies should be designed to determine whether adipsin is linked to IR-associated susceptibility to early cognitive decline in T2DM patients.

15.
Retina ; 2019 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-31567816

RESUMO

PURPOSE: This study evaluates the efficacy and usefulness of vitrectomy with internal limiting membrane peeling and autologous blood clot covering without gas tamponade in the treatment of macular holes (MHs). METHODS: All patients with a full-thickness MH with a minimum diameter of <600 µm and a base diameter of <1,200 µm underwent pars plana vitrectomy and internal limiting membrane peeling with autologous blood covering the MH at the end of the surgery. No fluid-air exchange or gas tamponade was performed. Postoperatively, all patients were instructed to adopt supine position overnight and thereafter any comfortable posture. RESULTS: A total of 18 eyes of 18 consecutive patients were included. The mean age of the patients (12 women and 6 men) was 59.06 ± 14.31 years (range, 21-81 years). The MHs composed of 13 idiopathic MHs, 2 MHs with high myopia (axial length > 26.5 mm), 2 traumatic MHs, and 1 MH associated with diabetic macular edema. Among them were five large MHs (minimum diameter > 400 µm). Complete MH closure was achieved in all eyes at the end of the follow-up period (range, 3-14 months). Visual acuity was significantly improved from preoperative 0.89 ± 0.41 logarithm of the minimum angle of resolution (20/155 Snellen) to 0.42 ± 0.33 logarithm of the minimum angle of resolution (20/53 Snellen) at the final visit (P < 0.001). CONCLUSION: The novel surgical protocol using vitrectomy, internal limiting membrane peeling, and autologous blood clot covering at the end of the MH surgery with limited diameters achieved highly effective closure and visual improvement and eliminated the gas tamponade and thus the associated adverse effects and the need for postoperative face-down positioning.

16.
Artigo em Inglês | MEDLINE | ID: mdl-31568262

RESUMO

OBJECTIVES: To elucidate etiologies, treatment, functional and neurocognitive outcomes of children with new-onset refractory status epilepticus. DESIGN: A single-center retrospective study. SETTING: A tertiary care children's hospital. PATIENTS: All patients between 1 month and 21 years old admitted with new-onset refractory status epilepticus between January 2004 and July 2017. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Clinical presentation, laboratory data, imaging studies, and treatments were collected during hospitalization. Outcomes were assessed at hospital discharge and follow-up in the outpatient neurology clinic based on functional and neurocognitive outcomes as well as development of epilepsy. A total of 674 unique patients presented with status epilepticus of which 40 had new-onset refractory status epilepticus. Patients were classified into either refractory status epilepticus or super-refractory status epilepticus. The etiology of most children with new-onset refractory status epilepticus remained cryptogenic. The most common identified etiology was viral (20%). None of the patients had a contributory positive neuronal antibody test. Several treatments were tried including immunotherapy which was used in half of the patients. Five patients died (12.5%) during the acute phase of their disease, with four lost to follow-up. Twenty out of the remaining 31 patients (65%) developed epilepsy and 18 (58%) had persistent neurocognitive impairment. There was no statistical significant difference in various outcome measures and various etiologies, patients' characteristics, and treatments. CONCLUSIONS: In this single-center cohort, more than half of the children with new-onset refractory status epilepticus did not have an identifiable etiology. Unlike adult patients, the presence of positive neuronal antibody syndrome was rare. There was no difference in outcome between those with or without an identifiable etiology. As expected, patients with super-refractory status epilepticus had worse functional and neurocognitive outcomes. More standardized diagnostic and treatment algorithms are needed along with prospective multicenter studies.

17.
J Lipid Res ; 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31570505

RESUMO

During foam cell formation and atherosclerosis development, the scavenger receptor CD36 plays critical roles in lipid uptake and triggering of atherogenicity via activation of Vav molecules. Vav family includes 3 highly conserved members known as Vav1, Vav2 and Vav3. As Vav1 and Vav3 were found to exert function in atherosclerosis development, it remains thus to decipher whether Vav2 also plays a role in the development of atherosclerosis. In this study we found that Vav2 deficiency in RAW264.7 macrophages diminished significantly Oxidized low-density lipoprotein (Ox-LDL) uptake and CD36 signaling, demonstrating that each Vav protein family member was required for foam cell formation. Genetic disruption of Vav2 in ApoE-deficient C57BL/6 mice significantly inhibited the severity of atherosclerosis. Strikingly, we further found that genetic deletion of each member of the Vav protein family by CRISPR/Cas9 resulted in similar alteration of transcriptomic profiles of macrophages. The three members of the Vav proteins were found to form complexes, and genetic ablation of each single Vav molecule was sufficient to prevent endocytosis of CD36. The functional interdependence of the three Vav family members in foam cell formation was due to their indispensable roles in transcriptomic programing, lipid uptake, and activation of the JNK kinase in macrophages.

18.
Nucleic Acids Res ; 47(20): 10520-10528, 2019 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-31584083

RESUMO

We have found recently that nuclear uptake of the cell-impermeable DNA light-switching Ru(II)-polypyridyl cationic complexes such as [Ru(bpy)2(dppz)]Cl2 was remarkably enhanced by pentachlorophenol (PCP), by forming ion-pairing complexes via a passive diffusion mechanism. However, it is not clear whether the enhanced nuclear uptake of [Ru(bpy)2(dppz)]2+ is only limited to PCP, or it is a general phenomenon for other highly chlorinated phenols (HCPs); and if so, what are the major physicochemical factors in determining nuclear uptake? Here, we found that the nuclear uptake of [Ru(bpy)2(dppz)]2+ can also be facilitated by other two groups of HCPs including three tetrachlorophenol (TeCP) and six trichlorophenol (TCP) isomers. Interestingly and unexpectedly, 2,3,4,5-TeCP was found to be the most effective one for nuclear delivery of [Ru(bpy)2(dppz)]2+, which is even better than the most-highly chlorinated PCP, and much better than its two other TeCP isomers. Further studies showed that the nuclear uptake of [Ru(bpy)2(dppz)]2+ was positively correlated with the binding stability, but to our surprise, inversely correlated with the lipophilicity of the ion-pairing complexes formed between [Ru(bpy)2(dppz)]Cl2 and HCPs. These findings should provide new perspectives for future investigations on using ion-pairing as an effective method for delivering other bio-active metal complexes into their intended cellular targets.

19.
J Colloid Interface Sci ; 556: 401-410, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31472314

RESUMO

Achieving sustainable energy technology with outstanding performance and clean materials for overall water splitting, while fascinating, still include many challenges. Herein, the masterly CoNi2S4@CoS2/NF 3D microspheres assembled by peapod-like nanorods with a mass of CoS2 particles are successfully prepared on nickel foam. The well-preserved 3D porous materials with unique heterostructure have various merits including more electronic channels, small electrons transfer resistance and open interior space. Besides, the unique peapod-like structure endows the catalyst plentiful, dispersive and exposed reactive sites, which is vital important to significantly increase the electrochemical performance. Notably, the as-prepared CoNi2S4@CoS2/NF catalysts achieve optimized electrocatalytic activity for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) at low overpotentials of 259 mV and 173 mV while deliver 10 mA cm-2 current density, respectively. It can be anticipated that it is a potential alternative catalyst for rational utilization in electrolytic water splitting fields.

20.
Proc Natl Acad Sci U S A ; 116(40): 20201-20209, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31530723

RESUMO

Action potential-induced vesicular exocytosis is considered exclusively Ca2+ dependent in Katz's Ca2+ hypothesis on synaptic transmission. This long-standing concept gets an exception following the discovery of Ca2+-independent but voltage-dependent secretion (CiVDS) and its molecular mechanisms in dorsal root ganglion sensory neurons. However, whether CiVDS presents only in sensory cells remains elusive. Here, by combining multiple independent recordings, we report that [1] CiVDS robustly presents in the sympathetic nervous system, including sympathetic superior cervical ganglion neurons and slice adrenal chromaffin cells, [2] uses voltage sensors of Ca2+ channels (N-type and novel L-type), and [3] contributes to catecholamine release in both homeostatic and fight-or-flight like states; [4] CiVDS-mediated catecholamine release is faster than that of Ca2+-dependent secretion at the quantal level and [5] increases Ca2+ currents and contractility of cardiac myocytes. Together, CiVDS presents in the sympathetic nervous system with potential physiological functions, including cardiac muscle contractility.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA