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1.
N Engl J Med ; 382(20): 1926-1932, 2020 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-32402162

RESUMO

We report the implantation of patient-derived midbrain dopaminergic progenitor cells, differentiated in vitro from autologous induced pluripotent stem cells (iPSCs), in a patient with idiopathic Parkinson's disease. The patient-specific progenitor cells were produced under Good Manufacturing Practice conditions and characterized as having the phenotypic properties of substantia nigra pars compacta neurons; testing in a humanized mouse model (involving peripheral-blood mononuclear cells) indicated an absence of immunogenicity to these cells. The cells were implanted into the putamen (left hemisphere followed by right hemisphere, 6 months apart) of a patient with Parkinson's disease, without the need for immunosuppression. Positron-emission tomography with the use of fluorine-18-L-dihydroxyphenylalanine suggested graft survival. Clinical measures of symptoms of Parkinson's disease after surgery stabilized or improved at 18 to 24 months after implantation. (Funded by the National Institutes of Health and others.).


Assuntos
Neurônios Dopaminérgicos/citologia , Células-Tronco Pluripotentes Induzidas/transplante , Doença de Parkinson/terapia , Parte Compacta da Substância Negra/citologia , Idoso , Animais , Gânglios da Base/diagnóstico por imagem , Gânglios da Base/metabolismo , Diferenciação Celular , Modelos Animais de Doenças , Neurônios Dopaminérgicos/metabolismo , Neurônios Dopaminérgicos/transplante , Seguimentos , Humanos , Células-Tronco Pluripotentes Induzidas/imunologia , Masculino , Camundongos , Camundongos SCID , Doença de Parkinson/diagnóstico por imagem , Tomografia por Emissão de Pósitrons , Putamen/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Transplante Autólogo , Transplante Homólogo
2.
Nat Chem Biol ; 2020 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-32451509

RESUMO

The orphan nuclear receptor Nurr1 is critical for the development, maintenance and protection of midbrain dopaminergic (mDA) neurons. Here we show that prostaglandin E1 (PGE1) and its dehydrated metabolite, PGA1, directly interact with the ligand-binding domain (LBD) of Nurr1 and stimulate its transcriptional function. We also report the crystallographic structure of Nurr1-LBD bound to PGA1 at 2.05 Å resolution. PGA1 couples covalently to Nurr1-LBD by forming a Michael adduct with Cys566, and induces notable conformational changes, including a 21° shift of the activation function-2 helix (H12) away from the protein core. Furthermore, PGE1/PGA1 exhibit neuroprotective effects in a Nurr1-dependent manner, prominently enhance expression of Nurr1 target genes in mDA neurons and improve motor deficits in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-lesioned mouse models of Parkinson's disease. Based on these results, we propose that PGE1/PGA1 represent native ligands of Nurr1 and can exert neuroprotective effects on mDA neurons, via activation of Nurr1's transcriptional function.

3.
New Phytol ; 2020 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-32392385

RESUMO

Whole-genome annotation error that omits essential protein-coding genes hinders further research. We developed Target Gene Family Finder (TGFam-Finder), an alternative tool for the structural annotation of protein-coding genes containing target domain(s) of interest in plant genomes. TGFam-Finder took considerably reduced annotation run-time and improved accuracy compared to conventional annotation tools. Large-scale re-annotation of 50 plant genomes identified an average of 150, 166 and 86 additional far-red-impaired response 1, nucleotide-binding and leucine-rich-repeat, and cytochrome P450 genes, respectively, that were missed in previous annotations. We detected significantly higher number of translated genes in the new annotations using mass spectrometry data from seven plant species compared to previous annotations. TGFam-Finder along with the new gene models can provide an optimized platform for comprehensive functional, comparative, and evolutionary studies in plants.

4.
Investig Clin Urol ; 61(2): 127-135, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32158963

RESUMO

Purpose: This study aimed to evaluate the feasibility of pan-cancer panel analysis for locally advanced prostate cancer in the Korean population. Materials and Methods: We analyzed 20 patients with locally advanced prostate cancer who underwent radical prostatectomy. A pan-cancer panel (1.9 Mbp) developed by Seoul National University Hospital (SNUH), composed of 183 target genes, 23 fusion genes, and 45 drug target regions was used for this analysis. We compared the SNUH pan-cancer panel results with The Cancer Genome Atlas (TCGA) database to search for different mutations in the Korean population. Clinical data were analyzed with univariate and multivariate analysis, and p-values <0.05 were considered statistically significant. Kaplan-Meier curve and log-rank tests were performed to evaluate survival. Results: The average age of the patients and initial prostate-specific antigen values were 69.3±7.8 years and 66.3±16.9 ng/dL, respectively. Average sequencing depth was 574.5±304.1×. Ninety-nine genetic mutations and 5 fusions were detected. SPOP (25%), KMT2D (20%), and BRAF (15%) were frequently detected. ERG fusions were recurrently detected in 20% of the patients, with SLMAP and SETD4 as novel fusion partners. BRAF mutation was frequently detected in this study, but not in the TCGA database. Multivariate analysis showed BRAF mutation as an independent prognostic factor for biochemical recurrence (hazard ratio, 9.84; p=0.03). Conclusions: The pan-cancer panel comprising genes related to prostate cancer is a useful tool for evaluating genetic alterations in locally advanced prostate cancers. Our results suggest that the BRAF mutation is associated with biochemical recurrence in the Korean population.

5.
J Sci Food Agric ; 100(7): 2819-2827, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31985064

RESUMO

BACKGROUND: With a growing market for functional foods, the nutraceutical properties of hemp sprouts have been investigated in recent studies. However, commercial mass production methods have yet to be developed. This study aimed to identify seed sizes suitable for segregating ripe seeds, which would improve the low germination rate in the high seed densities used in commercial hemp sprout production. RESULTS: Seeds ranging in size from 2.80 to 3.3 mm, collected by sieving, were the most suitable for sprouting, based on the distribution rate (74.9%) and germination rate (70.0%) at a low seed density (0.016 grains mm-2 ). Seed segregation by sinking the seeds in 70% ethanol after 2 h or more of water infiltration generated high germination rates of 86.3% to 94.3% at low seed density, compared to a 64.0% germination rate in non-segregated seeds. The hemp seed germination rate decreased geometrically with increasing sowing density. The germination rate with a high seed density (0.29 grains mm-2 ) was increased from 19.9% when seeds were not mixed with sand to 58.7% when mixed with sand in a 3:1 ratio. The sprouting yield significantly increased from 1.64 kg kg-1 when seeds were not mixed with sand to 9.55 kg kg-1 in seeds germinating when mixed with sand. Delta-9-tetrahydrocannabinol was not detected in hemp sprout. CONCLUSION: The production of hemp sprouts may be improved by identifying suitable seed sizes, segregating ripe seeds, and germinating seeds mixed with sand. This can be used in the commercial production of hemp sprouts. The sprouts were also found to be safe and without hallucinogenic effects. © 2020 Society of Chemical Industry.

6.
J Immunol Methods ; 479: 112750, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31981564

RESUMO

The specific recognition between a monoclonal antibody (mAb) and its epitope can be used in a tag system that has proved valuable in a wide range of biological applications. Herein, we describe a novel tag called RA-tag that is composed of a seven amino acid sequence (DIDLSRI) and recognized by a highly specific mAb, 47RA, against the bacterial toxin Vibrio vulnificus RtxA1/MARTXVv. By using recombinant proteins with the RA-tag at the N-terminal, C-terminal, or an internal site, we demonstrated that the tag system could be an excellent biological system for both protein purification and protein detection in enzyme-linked immunosorbent, Western blot, flow cytometry, and immunofluorescence staining analyses in Escherichia coli, mammalian cell lines, yeast, and plant. In addition, our RA-tag/47RA mAb combination showed high sensitivity and reliable affinity (KD = 5.90 × 10-8 M) when compared with conventional tags. Overall, our results suggest that the RA-tag system could facilitate the development of a broadly applicable tag system for biological research.

7.
Sci Rep ; 10(1): 870, 2020 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-31964919

RESUMO

We propose a weighted ensemble approach using a surrogate variable. As a case study, the degree of agreement (DOA) statistics for potential evapotranspiration (PET) was determined to compare the ordinary arithmetic mean ensemble (OAME) method and the surrogate weighted mean ensemble (SWME) method for three domains. Solar radiation was used as the surrogate variable to determine the weight values for the ensemble members. Singular vector decomposition with truncation values was used to select five ensemble members for the SWME method. The SWME method tended to have greater DOA statistics for PET than the OAME method with all available models. The distribution of PET values for the SWME method also had greater DOA statistics than that for the OAME method over relatively large spatial extent by month. These results suggest that the SWME method based on the weight value derived from the surrogate variable is suitable for exploiting both diversity and elitism to minimize the uncertainty of PET ensemble data. These findings could contribute to a better design of climate change adaptation options by improving confidence of PET projection data for the assessment of climate change impact on natural and agricultural ecosystems using the SWME method.

8.
Oper Neurosurg (Hagerstown) ; 18(3): 321-328, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31214702

RESUMO

BACKGROUND: Surgical implantation of cellular grafts into the brain is of increasing importance, as stem cell-based therapies for Parkinson and other diseases continue to develop. The effect of grafting technique on development and survival of the graft has received less attention. Rate and method of graft delivery may impact the cell viability and success of these therapies. Understanding the final location of the graft with respect to the intended target location is also critical. OBJECTIVE: To describe a "columnar injection" technique designed to reduce damage to host tissue and result in a column of graft material with greater surface area to volume ratio than traditional injection techniques. METHODS: Using a clinically relevant model system of human embryonic stem cell-derived dopaminergic progenitors injected into athymic rat host brain, we describe a novel device that allows separate control of syringe barrel and plunger, permitting precise deposition of the contents into the cannula tract during withdrawal. Controls consist of contralateral injection using traditional techniques. Graft histology was examined at graft maturity. RESULTS: Bolus grafts were centered on the injection tract but were largely proximal to the "target" location. These grafts displayed a conspicuous peripheral distribution of cells, particularly of mature dopaminergic neurons. In contrast, column injections remained centered at the intended target, contained more evenly distributed cells, and had significantly more mature dopaminergic neurons. CONCLUSION: We suggest that this columnar injection technique may allow better engraftment and development of intracerebral grafts, enhancing outcomes of cell therapy, compared to fixed-point injection techniques.

9.
J Hazard Mater ; 384: 121274, 2020 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-31585279

RESUMO

Here, we have investigated the effect of UV-pretreatment on the physicochemical properties of an adsorbent. The UV-irradiated Fe-incorporated ZSM-5 (UV-FZ5) showed structural and chemical changes arising due to UV-cleaving of framework bonds resulting in a decreased crystallinity and change in the local environment of Fe species. More visible modifications were observed for UV-irradiated iron-containing silica (UV-Fe/AS) where silica network reconfiguration, increased hydroxyl density, and change in the Fe coordination were estimated. A 0.5-81.2% increase in BTEX adsorption was recorded for UV-irradiated adsorbents. These hiked performances were attributed to the increased pore size, increased hydroxyl density, and formation of newer isolated Fe3+ framework species. For FZ5, adsorption occurred via size-selective diffusion followed by hydrogen bonding and cation-pi interaction, whereas, for Fe/AS, diffusion was followed by cation-pi interactions. Moreover, adsorbents retained their adsorption capacity for multiple cycles and were found economically suitable for treating VOCs-contaminated air.

10.
Bioresour Technol ; 297: 122399, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31759855

RESUMO

Lignin nano-/microstructures are widely employed for agricultural drug delivery and heavy metal removal from wastewater, and facile low-cost methods of their large-scale production are therefore highly sought after. Herein, uniform-morphology polydisperse lignin microspheres were directly extracted from black liquor by lowering its pH to <4 followed by hydrothermal treatment and featured several lignin-typical characteristics, e.g., functional groups, thermal stability, amorphousness, and monolignol units. It was assumed that lignin rearranged and assembled into microspheres of various size, shape, and uniformity depending on pH, temperature, and hydrothermal treatment time. Lignin microsphere extraction efficiency was estimated as 15.87-21.62 g L-1, and the average size of microspheres obtained under different conditions was calculated as ∼1 µm, while the C, H, O, and N contents equaled 48-62, 5-6, 30-36, and 0.2-1.5%, respectively. Thus, our method was deemed suitable for direct large-scale extraction of lignin microspheres from black liquor.


Assuntos
Lignina , Águas Residuárias , Bebidas Alcoólicas , Microesferas , Temperatura
11.
J Clin Invest ; 130(2): 904-920, 2020 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-31714896

RESUMO

Parkinson's disease (PD) is a neurodegenerative disorder associated with loss of striatal dopamine, secondary to degeneration of midbrain dopamine (mDA) neurons in the substantia nigra, rendering cell transplantation a promising therapeutic strategy. To establish human induced pluripotent stem cell-based (hiPSC-based) autologous cell therapy, we report a platform of core techniques for the production of mDA progenitors as a safe and effective therapeutic product. First, by combining metabolism-regulating microRNAs with reprogramming factors, we developed a method to more efficiently generate clinical-grade iPSCs, as evidenced by genomic integrity and unbiased pluripotent potential. Second, we established a "spotting"-based in vitro differentiation methodology to generate functional and healthy mDA cells in a scalable manner. Third, we developed a chemical method that safely eliminates undifferentiated cells from the final product. Dopaminergic cells thus express high levels of characteristic mDA markers, produce and secrete dopamine, and exhibit electrophysiological features typical of mDA cells. Transplantation of these cells into rodent models of PD robustly restores motor function and reinnervates host brain, while showing no evidence of tumor formation or redistribution of the implanted cells. We propose that this platform is suitable for the successful implementation of human personalized autologous cell therapy for PD.

12.
Int J Med Sci ; 16(12): 1557-1563, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31839743

RESUMO

E2F3, a member of the E2F family, plays a critical role in cell cycle and proliferation by targeting downstream, retinoblastoma (RB) a tumor suppressor family protein. The purpose of this study, was to investigate the role and function of E2F3 in vivo. We examined phenotypic abnormalities, by deletion of the E2f3 gene in mice. Complete ablation of the E2F3 was fully penetrant, in the pure C57BL/6N background. The E2f3+/ - mouse embryo developed normally without fatal disorder. However, they exhibited reduced body weight, growth retardation, skeletal imperfection, and poor grip strength ability. Findings suggest that E2F3 has a pivotal role in muscle and bone development, and affect normal mouse growth.


Assuntos
Desenvolvimento Ósseo/genética , Fator de Transcrição E2F3/genética , Desenvolvimento Embrionário/genética , Músculo Esquelético/crescimento & desenvolvimento , Animais , Apoptose/genética , Peso Corporal/genética , Ciclo Celular/genética , Proliferação de Células/genética , Embrião de Mamíferos , Humanos , Camundongos , Camundongos Knockout , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiopatologia , Fenótipo
13.
Sci Rep ; 9(1): 16928, 2019 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-31729416

RESUMO

Increasing evidence suggests a role for inflammation in neuropsychiatric conditions including autism spectrum disorder (ASD), a neurodevelopmental syndrome with higher prevalence in males than females. Here we examined the effects of early-life immune system activation (EIA)-comprising regimens of prenatal, early postnatal, or combined ("two-hit") immune activation-on the core behavioral features of ASD (decreased social interaction, increased repetitive behavior, and aberrant communication) in C57BL/6J mice. We treated timed-pregnant mice with polyinosinic:polycytidylic acid (Poly I:C) on gestational day 12.5 to produce maternal immune activation (MIA). Some offspring also received lipopolysaccharide (LPS) on postnatal day 9 to produce postnatal immune activation (PIA). EIA produced disruptions in social behavior and increases in repetitive behaviors that were larger in males than in females. Ultrasonic vocalizations (USVs) were altered in both sexes. Molecular studies revealed that EIA also produced prominent sex-specific changes in inflammation-related gene expression in the brain. Whereas both sexes showed increases in pro-inflammatory factors, as reflected by levels of mRNA and protein, expression of anti-inflammatory factors was decreased in males but increased in females. Our findings demonstrate that EIA can produce sex-specific behavioral effects and immune responses in the brain, and identify molecular processes that may contribute to resilience in females.

14.
Plant Signal Behav ; 14(12): 1678369, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31610733

RESUMO

The use of rapeseed (Brassica napus L.) or leaf mustard (Brassica juncea L. Czern) meal or both as organic fertilizer not only improves the soil environment and crop productivity by supplying nutrients but also has nematicidal effects. This study aimed to establish the optimal application levels of rapeseed and leaf mustard meal for stronger nematode control in tomato. Tomato is one of the most important solanaceous crops which is severely damaged by nematodes. At first, meal (120 g of varying mixing ratios of rapeseed and leaf mustard meal) was mixed with sterilized soil (1 kg). The optimal ratio of rapeseed:leaf mustard meal for effective nematode control was 20:100 g/kg of soil. Progoitrin and gluconapin were the most abundant glucosinolates found in rapeseed meal, while sinigrin was the most abundant in leaf mustard meal. The amount of sinigrin increased if the leaf mustard meal proportion increased in the meal mixture. Although the content of sinigrin in optimal ratio mixture of rapeseed and leaf mustard meal is lower than only leaf mustard meal, it is presumed that nematocidal effects of the mixture are better than that of the single component due to the high contents of progoitrin and gluconapin. So, we propose that rapeseed and leaf mustard meal mixture at an appropriate ratio can be used as an environmentally friendly nematocide.

15.
Sci Rep ; 9(1): 15559, 2019 10 29.
Artigo em Inglês | MEDLINE | ID: mdl-31664129

RESUMO

For over a half-century the anti-malarial drug chloroquine (CQ) has been used as a therapeutic agent, alone or in combination, to treat autoimmune diseases. However, neither the underlying mechanism(s) of action nor their molecular target(s) are well defined. The orphan nuclear receptor Nurr1 (also known as NR4A2) is an essential transcription factor affecting the development and maintenance of midbrain dopaminergic neurons. In this study, using in vitro T cell differentiation models, we demonstrate that CQ activates TREG cell differentiation and induces Foxp3 gene expression in a Nurr1-dependent manner. Remarkably, CQ appears to induce Nurr1 function by two distinct mechanisms: firstly, by direct binding to Nurr1's ligand-binding domain and promoting its transcriptional activity and secondly by upregulation of Nurr1 expression through the CREB signaling pathway. In contrast, CQ suppressed gene expression and differentiation of pathogenic TH17 cells. Importantly, using a valid animal model of inflammatory bowel disease (IBD), we demonstrated that CQ promotes Foxp3 expression and differentiation of TREG cells in a Nurr1-dependent manner, leading to significant improvement of IBD-related symptoms. Taken together, these data suggest that CQ ameliorates autoimmune diseases via regulating Nurr1 function/expression and that Nurr1 is a promising target for developing effective therapeutics of human inflammatory autoimmune diseases.

16.
Mol Cancer Res ; 17(11): 2257-2266, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31511359

RESUMO

ZEB1 has intrinsic oncogenic functions that control the epithelial-to-mesenchymal transition (EMT) of cancer cells, impacting tumorigenesis from its earliest stages. By integrating microenvironment signals and being implicated in feedback regulatory loops, ZEB1 appears to be a central switch that determines EMT and metastasis of cancer cells. Here, we found that ZEB1 collaborates with ELK3, a ternary complex factor belonging to the ETS family, to repress E-cadherin expression. ZEB1 functions as a transcriptional activator of ELK3. We first identified that ELK3 and ZEB1 have a positively correlated expression in breast cancer cells by using multiple databases for correlation analysis. Molecular analysis revealed that ZEB1 functions as a transcriptional activator of ELK3 expression. GST pull-down assay and coimmunoprecipitation analysis of wild-type or domain deletion mutants of ZEB1 and ELK3 showed that these 2 proteins directly bound each other. Furthermore, we demonstrated that ZEB1 and ELK3 collaborate to repress the expression of E-cadherin, a representative protein that initiates EMT. Our finding suggested that ELK3 is a novel factor of the ZEB1/E-cadherin axis in triple-negative breast cancer cells. IMPLICATIONS: ELK3 is a novel factor in the ZEB1/E-cadherin axis and ZEB1 has a dual role in ELK3 as a transcriptional activator and as a collaborator to repress E-cadherin expression in triple-negative breast cancer cells.

17.
Biomaterials ; 221: 119418, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31419655

RESUMO

Recently, natural killer (NK)-based immunotherapy has attracted attention as a next-generation cell-based cancer treatment strategy due to its mild side effects and excellent therapeutic efficacy. Here, we describe multifunctional nanoparticles (MF-NPs) capable of genetically manipulating NK cells and tracking them in vivo through non-invasive magnetic resonance (MR) and fluorescence optical imaging. The MF-NPs were synthesized with a core-shell structure by conjugation of a cationic polymer labeled with a near-infrared (NIR) fluorescent molecule, with the aid of a polydopamine (PDA) coating layer. When administered to NKs, the MF-NPs exhibited excellent cytocompatibility, efficiently delivered genetic materials into the immune cells, and induced target protein expression. In particular, the MF-NPs could induce the expression of EGFR targeting chimeric antigen receptors (EGFR-CARs) on the NK cell surface, which improved the cells' anti-cancer cytotoxic effect both in vitro and in vivo. Finally, when NK cells labeled with MF-NPs were injected into live mice, MF-NP-labeled NK cells could be successfully imaged using fluorescence and MR imaging devices. Our findings indicate that MF-NPs have great potential for application of NK cells, as well as other types of cell therapies involving genetic engineering and in vivo monitoring of cell trafficking.

18.
Sci Rep ; 9(1): 8418, 2019 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-31182803

RESUMO

Tumor-associated lymphatic vessels (LV) serve as a route of cancer dissemination through the prometastatic crosstalk between lymphatic endothelial cells (LECs) lining the LVs and cancer cells. Compared to blood endothelial cell-derived angiocrine factors, however, LEC-secreted factors in the tumor microenvironment and their roles in tumor metastasis are poorly understood. Here, we report that ELK3 expressed in LECs contributes to the dissemination of cancer cells during tumor growth by providing oncogenic miRNAs to tumor cells through exosomes. We found that conditioned medium from ELK3-suppressed LECs (LCM) lost its ability to promote the migration and invasion of breast cancer cells such as MDA-MB-231, Hs578T and BT20 in vitro. Suppression of ELK3 in LECs diminished the ability of LECs to promote tumor growth and metastasis of MDA-MB-231 in vivo. Exosomes derived from LECs significantly increased the migration and invasion of MDA-MB-231 in vitro, but ELK3 suppression significantly diminished the pro-oncogenic activity of exosomes from LECs. Based on the miRNA expression profiles of LECs and functional analysis, we identified miR-503-3p, miR-4269 and miR-30e-3p as downstream targets of ELK3 in LECs, which cause the above phenotype of cancer cells. These findings strongly suggest that ELK3 expressed in LECs is a major regulator that controls the communication between the tumor microenvironment and tumors to support cancer metastasis.

19.
Water Res ; 158: 246-256, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31048194

RESUMO

In this study, Fe-Zeolite-A as a phosphate adsorbent was synthesized by incorporating iron into the framework of Zeolite-A using ammonium iron citrate as the Fe3+source. The adsorption (in acidic condition) and desorption of phosphate (in alkaline condition) from an aqueous solution was repetitively performed for 18 times in batch test using Fe-Zeolite-A. The rate of adsorption and desorption of PO43- was much faster (consistently) than any of the reported study so far. The crystalline phase of pristine zeolite changed to amorphous after one adsorption phase and ultimately transformed into a highly amorphous phase after 18 adsorption/desorption cycles. It was due to the formation of more active sites on the surface of the zeolite by a release of atoms, breaking of bonds and deposition of metal and phosphate compounds on the surface (by rigorous acid/base treatment). Increase in active sites enhanced the sorption efficiency of Fe-Zeolite-A. With the help of microscopic and spectroscopic techniques, it was found that Fe3+, Al3+and Na+ metal ions of the Fe-Zeolite-A were involved in the adsorption/desorption of PO43-. Fe3+ ion exhibited ligand exchange mechanism by exchanging OH ions with PO43-. Al3+and Na+ exhibited interactions like precipitation, hydrogen bonding, and diffusion respectively to adsorb PO43-. Fe3+ metal ion dominated over other metal ions by ligand exchange principle, making the sorption process a highly reversible one. The adsorbent showed quantitative adsorption/desorption capacity even after continuous 18 cycles indicating a higher level of reusability.


Assuntos
Zeolitas , Adsorção , Concentração de Íons de Hidrogênio , Íons , Ferro , Fosfatos
20.
Adv Mater ; 31(23): e1900613, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30993785

RESUMO

White organic light-emitting diode (WOLED) technology has attracted considerable attention because of its potential use as a next-generation solid-state lighting source. However, most of the reported WOLEDs that employ the combination of multi-emissive materials to generate white emission may suffer from color instability, high material cost, and a complex fabrication procedure which can be diminished by the single-emitter-based WOLED. Herein, a color-tunable material, tris(4-(phenylethynyl)phenyl)amine (TPEPA), is reported, whose photoluminescence (PL) spectrum is altered by adjusting the thermal annealing temperature nearly encompassing the entire visible spectra. Density functional theory calculations and transmission electron microscopy results offer mechanistic understanding of the PL redshift resulting from thermally activated rotation of benzene rings and rotation of 4-(phenylethynyl) phenyl)amine connected to the central nitrogen atom that lead to formation of ordered molecular packing which improves the π-π stacking degree and increases electronic coupling. Further, by precisely controlling the annealing time and temperature, a white-light OLED is fabricated with the maximum external quantum efficiency of 3.4% with TPEPA as the only emissive molecule. As far as it is known, thus far, this is the best performance achieved for single small organic molecule based WOLED devices.

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