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1.
JACS Au ; 3(11): 3089-3100, 2023 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-38034952

RESUMO

Selective ion separation from brines is pivotal for attaining high-purity lithium, a critical nonrenewable resource. Conventional methods encounter substantial challenges, driving the quest for streamlined, efficient, and swift approaches. Here, we present a graphene oxide (GO)-based ternary heterostructure membrane with a unique design. By utilizing Zn2+-induced confinement synthesis in a two-dimensional (2D) space, we incorporated two-dimensional zeolitic imidazolate framework-8 (ZIF-8) and zinc alginate (ZA) polymers precisely within layers of the GO membrane, creating tunable interlayer channels with a ternary heterostructure. The pivotal design lies in ion insertion into the two-dimensional (2D) membrane layers, achieving meticulous modulation of layer spacing based on ion hydration radius. Notably, the ensuing layer spacing within the hybrid ionic intercalation membrane occupies an intermediary realm, positioned astutely between small-sized hydrated ionic intercalation membrane spacing and their more extensive counterparts. This deliberate configuration accelerates the swift passage of diminutive hydrated ions while simultaneously impeding the movement of bulkier ions within the brine medium. The outcome is remarkable selectivity, demonstrated by the partitioning of K+/Li+ = 20.9, Na+/K+ = 31.2, and Li+/Mg2+ = 9.5 ion pairs. The ZIF-8/GO heterostructure significantly contributes to the selectivity, while the mechanical robustness and stability, improved by the ZA/GO heterostructure, further support its practical applicability. This report reports an advanced membrane design, offering promising prospects for lithium extraction and various ion separation processes.

2.
Discov Nano ; 18(1): 112, 2023 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-37695406

RESUMO

MOFs have considerable adsorption capacity due to their huge specific surface area. They have the characteristics of photocatalysts for their organic ligands can absorb photons and produce electrons. In this paper, the photodegradation properties of TiO2 composites loaded with UiO-66 were investigated for the first time for MO. A series of TiO2@UiO-66 composites with different contents of TiO2 were prepared by a solvothermal method. The photocatalytic degradation of methyl orange (MO) was performed using a high-pressure mercury lamp as the UV light source. The effects of TiO2 loading, catalyst dosage, pH value, and MO concentration were investigated. The results showed that the degradation of MO by TiO2@UiO-66 could reach 97.59% with the addition of only a small amount of TiO2 (5 wt%). TiO2@UiO-66 exhibited significantly enhanced photoelectron transfer capability and inhibited efficient electron-hole recombination compared to pure TiO2 in MO degradation. The composite catalyst indicated good stability and reusability when they were recycled three times, and the photocatalytic reaction efficiencies were 92.54%, 88.76%, and 86.90%. The results provide a new option to design stable, high-efficiency MOF-based photocatalysts.

3.
Nano Lett ; 23(20): 9641-9650, 2023 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-37615333

RESUMO

The wrinkles on graphene oxide (GO) membranes have unique properties; however, they interfere with the mass transfer of interlayer channels, posing a major challenge in the development of wrinkle-free GO membranes with smooth channels. In this study, the wrinkles on GO were flattened using vortex shear to tightly stack them into ultraflat GO membranes with Newton's ring interference pattern, causing hydrolysis of the lipid bonds in the wrinkles and an increase in the number of oxygen-containing groups. With increasing flatness, the interlayer spacing of the GO membranes decreased, improving the stability of the interlayer structure, the flow resistance of water through the ultraflat interlayer decreased, and the water flux increased 3-fold. Importantly, the selectivity for K+/Mg2+ reached approximately 379.17 in a real salt lake. A novel concept is proposed for the development of new membrane preparation methods. Our findings provide insights into the use of vortex shearing to flatten GO.

4.
Molecules ; 28(7)2023 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-37049647

RESUMO

Morchella esculenta (L.) Pers., referred to as Morel, is a medicinal and edible homologous fungus, which contains many bioactive substances. In Morel, polysaccharides are the most abundant and have various bioactivities. In the present work, two novel polysaccharides, Se-MPS and MPS, were prepared and purified from selenium-enriched (Se-enriched) and common Morel mycelia, respectively, and their structural and immunomodulatory properties were evaluated. The results show that Se-enriched treatment significantly changed the polysaccharides' chemical composition, molecular weight, and sugar chain configuration. In addition, the Se-enriched treatment also improved the polysaccharides' fragmentation and thermal stability. Importantly, Se-enriched Morel polysaccharide (Se-MPS) could significantly enhance phagocytosis of RAW 264.7 macrophage cells and, remarkably, activate their immune response via activating the TLR4-TRAF6-MAPKs-NF-κB cascade signaling pathway, finally exerting an immunomodulatory function. Based on these findings, selenium-enriched Morel polysaccharide appears to have more potential for development and utilization in functional foods or medicines than ordinary Morel polysaccharide.


Assuntos
Selênio , Selênio/química , Antioxidantes/química , Polissacarídeos/farmacologia , Polissacarídeos/química , Fagocitose
5.
Plant Foods Hum Nutr ; 78(2): 243-252, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37097509

RESUMO

Inulin is a naturally soluble dietary fiber that is widely distributed and primarily derived from plants. As a reserve biopolysaccharide in plants, inulin is considered an indigestible carbohydrate of fructan because of its unique ß-(2,1)-glycosidic bond structure. Numerous recent animal and human experimental studies have shown that functional inulin possesses multiple bioactivities, including immunomodulatory, antioxidant, antitumor, hepatoprotective, hypoglycemic, and gastrointestinal protective activities. Due to its increasing popularity, people tend to consume foods containing inulin. Moreover, inulin holds promise as a bioactive compound for use in the development of various food products. Therefore, this paper provides a detailed review of the extraction method, physicochemical properties, functional activity, and application development of inulin polysaccharides, to provide a theoretical foundation for further advancements in the fields of preparation and application of functional foods.


Assuntos
Inulina , Polissacarídeos , Animais , Humanos , Inulina/farmacologia , Polissacarídeos/farmacologia , Polissacarídeos/química , Frutanos , Carboidratos , Alimento Funcional
6.
Carbohydr Polym ; 300: 120259, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36372487

RESUMO

Uranium as a strategic and non-renewable resource has been paid close attention to its efficient recovery and reuse from uranium-containing wastewater. Here, a composite bead was prepared by functionalized graphene oxide and sodium alginate (L-Lys-GO/SA) with ion-stimuli responsiveness for achieving U(VI) adsorption. The L-Lys-GO/SA-60 composite beads can selectively adsorb U(VI) with the maximum adsorption capacity (qmax) of 704.22 mg/g. Interestingly, the composite beads will swell under the stimulation of ions, which is more conducive to rapid solid-liquid separation and U(VI) recovery at low energy consumption. More importantly, the composite beads also exhibit high reusability of U(VI) adsorption with excellent life span of 80.11 % adsorption rate after 9 cycles, meaning that the composite beads and technology may be used in extraction and production for U(VI) from uranium-containing wastewater.


Assuntos
Urânio , Alginatos , Águas Residuárias , Adsorção , Íons , Cinética
7.
BMC Med Imaging ; 22(1): 177, 2022 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-36241978

RESUMO

BACKGROUND: This study aimed to evaluate the artificial intelligence (AI)-based coronary artery calcium (CAC) quantification and regional distribution of CAC on non-gated chest CT, using standard electrocardiograph (ECG)-gated CAC scoring as the reference. METHODS: In this retrospective study, a total of 405 patients underwent non-gated chest CT and standard ECG-gated cardiac CT. An AI-based algorithm was used for automated CAC scoring on chest CT, and Agatston score on cardiac CT was manually quantified. Bland-Altman plots were used to evaluate the agreement of absolute Agatston score between the two scans at the patient and vessel levels. Linearly weighted kappa (κ) was calculated to assess the reliability of AI-based CAC risk categorization and the number of involved vessels on chest CT. RESULTS: The AI-based algorithm showed moderate reliability for the number of involved vessels in comparison to measures on cardiac CT (κ = 0.75, 95% CI 0.70-0.79, P < 0.001) and an assignment agreement of 76%. Considerable coronary arteries with CAC were not identified with a per-vessel false-negative rate of 59.3%, 17.8%, 34.9%, and 34.7% for LM, LAD, CX, and RCA on chest CT. The leading causes for false negatives of LM were motion artifact (56.3%, 18/32) and segmentation error (43.8%, 14/32). The motion artifact was almost the only cause for false negatives of LAD (96.6%, 28/29), CX (96.7%, 29/30), and RCA (100%, 34/34). Absolute Agatston scores on chest CT were underestimated either for the patient and individual vessels except for LAD (median difference: - 12.5, - 11.3, - 5.6, - 18.6 for total, LM, CX, and RCA, all P < 0.01; - 2.5 for LAD, P = 0.18). AI-based total Agatston score yielded good reliability for risk categorization (weighted κ 0.86, P < 0.001) and an assignment agreement of 86.7% on chest CT, with a per-patient false-negative rate of 15.2% (28/184) and false-positive rate of 0.5% (1/221) respectively. CONCLUSIONS: AI-based per-patient CAC quantification on non-gated chest CT achieved a good agreement with dedicated ECG-gated CAC scoring overall and highly reliable CVD risk categorization, despite a slight but significant underestimation. However, it is challenging to evaluate the regional distribution of CAC without ECG-synchronization.


Assuntos
Doença da Artéria Coronariana , Calcificação Vascular , Inteligência Artificial , Cálcio , Doença da Artéria Coronariana/diagnóstico por imagem , Humanos , Reprodutibilidade dos Testes , Estudos Retrospectivos , Tomografia Computadorizada por Raios X , Calcificação Vascular/diagnóstico por imagem
8.
Adv Mater ; 34(49): e2206524, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36127132

RESUMO

Deuterium water (D2 O) is a strategic material that is widely used in and scientific research and has applications in fields such as nuclear energy generation. However, its content in natural water is extremely low. Therefore, the development of a room-temperature technology for achieving simple, efficient, and low-cost separation of D2 O from natural water is challenging. In this study, porous graphene (PG) nanosheets with "crater-like" pores are sandwiched between two layers of graphene oxide (GO) membranes to prepare a GO/PG/GO membrane with a macroscopic heterostructure, which can be used to separate D2 O and H2 O by pressure-driven filtration. At 25 °C, the rejection rate of D2 O is ≈97%, the selectivity of H2 O/D2 O is ≈35.2, and the excellent performance can be attributed to the difference of transmembrane resistance and flow state of H2 O and D2 O in the confinement state. In addition, the D2 O concentration in natural water is successfully enriched from 0.013% to 0.059% using only one stage, and the membrane exhibits excellent structural and cycling stability. Therefore, this method does not require ultralow temperatures, high energy supplies, complex separation equipment, or the introduction of toxic chemicals. Thus, it can be directly applied to the large-scale industrial production and removal of D2 O.

9.
Int J Mol Sci ; 23(14)2022 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-35887009

RESUMO

Fruit ripening is usually accompanied by anthocyanin accumulation. Ethylene is key in ripening-induced anthocyanin production in many fruits. However, the effects of fruit ripening and ethylene on anthocyanin biosynthesis in purple tomato fruits are unclear. This study shows that bagged fruits of the purple tomato cultivar 'Indigo Rose' failed to produce anthocyanins at the red ripening stage after bag removal. In contrast, the bagged immature fruits accumulated a significant amount of anthocyanins after removing the bags. The transcriptomic analyses between immature and red ripening fruit before and after bag removal revealed that anthocyanin-related genes, including the key positive R2R3-MYB regulator SlAN2-like, were repressed in the red ripening fruit. The 86 identified transcription factors, including 13 AP2/ERF, 7 bZIP, 8 bHLH and 6 MYB, showed significantly different expressions between immature and red ripening fruits. Moreover, subjecting bagged immature fruits to exogenous ethylene treatment significantly inhibited anthocyanin accumulation and the expression of anthocyanin-related genes, including the anthocyanin structure genes and SlAN2-like. Thus, ethylene inhibits anthocyanin biosynthesis by repressing the transcription of SlAN2-like and other anthocyanin-related genes. These findings provide new insights into anthocyanin regulation in purple tomato fruit.


Assuntos
Solanum lycopersicum , Antocianinas/metabolismo , Etilenos/metabolismo , Frutas/metabolismo , Regulação da Expressão Gênica de Plantas , Solanum lycopersicum/genética , Solanum lycopersicum/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
10.
World J Clin Cases ; 10(14): 4404-4413, 2022 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-35663052

RESUMO

BACKGROUND: Due to dietary patterns, the aging population, and other high-risk factors, the occurrence of pancreatic cancer (PC) has been rapidly increasing in China. AIM: To present the epidemiological trends of PC in China over the past decade and the estimated trend in 2025 and to compare the international differences in PC morbidity and mortality. METHODS: This study used a series of nationally representative data from the National Central Cancer Registry of China (NCCR), the International Agency for Research on Cancer and the Institute for Health Metrics and Evaluation databases. Age-standardized data of the PC incidence and mortality from 2006 to 2015 in China were extracted from the NCCR database. Linear regression models were used to estimate the incidence and mortality rates of PC in 2025. RESULTS: The age-standardized rates of PC in China increased from 3.65 per 100000 in 2006 to 4.31 per 100000 in 2015 and were estimated to reach up to 5.52 per 100000 in 2025. The mortality went from 3.35 per 100000 in 2006 to 3.78 per 100000 in 2015, estimated to reach up to 4.6 per 100000 in 2025. The number of new cases and deaths was low before 45 years and the peak age of onset was 85-89 years. The incidence and mortality rates in men were higher than those in women regardless of the region in China. In addition, the incidence and mortality rates in China were higher than the average level around the world. Likewise, disability-adjusted life years attributed to PC in China were 197.22 years per 100000, above the average level around the world. CONCLUSION: This study presented an increasing trend of PC in China and differences in morbidity, mortality and disability-adjusted life years between Chinese and global populations. Efforts need to be made to decrease the PC incidence and improve patient outcomes.

11.
Front Pediatr ; 10: 871024, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35769218

RESUMO

Objective: To investigate whether feeding extensively hydrolysis protein formula during the NICU hospitalization was more beneficial for preterm infants with a gestational age (GA) ≤34 weeks when breastfeeding was not possible. Methods: In total, 587 preterm infants were randomly divided into two groups: observation groups fed with extensively hydrolyzed formula (EHF) milk and control groups fed with standard preterm formula (SPF) milk until discharge from the neonatal intensive care unit (NICU). The incidence of complications during hospitalization was recorded in both groups. Then, two groups were uniformly fed with 0-to-6-month infant formula milk and followed-up for 6 months after discharge. Results: The final study included 370 premature infants, including 185 babies in the observation group and 185 in the control group. In contrast to the SPF, feeding EHF among preterm infants of GA <34 weeks during NICU hospitalization significantly reduced the incidence of feeding intolerance (FI) (14.1 vs. 30.3%, p < 0.01). The incidence of necrotizing enterocolitis (NEC) was significantly reduced in the observation group (2.2 vs. 6.5%, p < 0.05), but there was no significant difference in the incidence of other related complications. At discharge, there was no difference in total serum protein (46.6 vs. 46.4 g/L), albumin (33.5 vs. 34.2 g/L), and calcium (2.37 vs. 2.35 mmol/L), but the serum phosphorus concentrations associated with skeletal mineralization (2.10 vs. 2.22 mmol/L, p < 0.05) was significantly reduced and alkaline phosphatase significantly rose (254 vs. 220 IU/L, p < 0.05) in the observation group. No significant difference was found in the growth rates of body weight, head circumference, or body length, either during the NICU hospitalization or during the 6-month follow-up after discharge (p > 0.05). Conclusions: Feeding premature infants of GA ≤34 weeks with EHF reduced the incidence of FI, but had no advantage in establishing whole intestinal nutrition, shortening parenteral nutrition (PN) time, or hospitalization time. It had little effect on physical growth or development during NICU hospitalization and within 6 months after discharge. However, it may increase the incidence of metabolic bone disease (MBD).

12.
Diagnostics (Basel) ; 12(5)2022 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-35626403

RESUMO

Background This study aims to explore a deep learning (DL) algorithm for developing a prognostic model and perform survival analyses in SBT patients. Methods The demographic and clinical features of patients with SBTs were extracted from the Surveillance, Epidemiology and End Results (SEER) database. We randomly split the samples into the training set and the validation set at 7:3. Cox proportional hazards (Cox-PH) analysis and the DeepSurv algorithm were used to develop models. The performance of the Cox-PH and DeepSurv models was evaluated using receiver operating characteristic curves, calibration curves, C-statistics and decision-curve analysis (DCA). A Kaplan−Meier (K−M) survival analysis was performed for further explanation on prognostic effect of the Cox-PH model. Results The multivariate analysis demonstrated that seven variables were associated with cancer-specific survival (CSS) (all p < 0.05). The DeepSurv model showed better performance than the Cox-PH model (C-index: 0.871 vs. 0.866). The calibration curves and DCA revealed that the two models had good discrimination and calibration. Moreover, patients with ileac malignancy and N2 stage disease were not responding to surgery according to the K−M analysis. Conclusions This study reported a DeepSurv model that performed well in CSS in SBT patients. It might offer insights into future research to explore more DL algorithms in cohort studies.

13.
Am J Transl Res ; 14(1): 328-335, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35173850

RESUMO

OBJECTIVE: To analyze the diagnostic value of capsule endoscopy (CE) and double-balloon enteroscopy (DBE) in small bowel diseases. METHODS: The clinical data of 134 cases of CE and 109 cases of DBE examined in our gastroscopy room from January 2016 to December 2019 were retrospectively analyzed. The two groups of patients were compared as to disease diagnostic rate, examination time, examination tolerance, and incidence of adverse reactions. RESULTS: The two groups showed no significant difference in general data (all P>0.05). The DBE group showed a higher disease diagnostic rate than the CE group (P<0.05). Significantly higher rates of suspected intestinal bleeding were observed in the DBE group than those of the CE group (P<0.05), but no significant differences were found in the diagnosis of unexplained abdominal pain, abdominal distension, and others (all P>0.05). The DBE group required a longer examination time, and had a higher incidence of adverse reactions, and a lower examination tolerance than the CE group (P<0.05). CONCLUSION: Both DBE and CE are effective in small bowel diseases diagnoses, but DBE demonstrated greater potential in diagnosing small bowel bleeding.

14.
Chin Med Sci J ; 37(4): 349-352, 2022 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-36647593

RESUMO

Autosomal recessive congenital ichthyosis (ARCI) is characterized by being born as collodion babies, hyperkeratosis, and skin scaling. We described a collodion baby at birth with mild ectropion, eclabium, and syndactyly. Whole exome sequencing showed a compound heterozygous variant c.[56C>A], p.(Ser19X) and c.[100G>A], p.(Ala34Thr) in the PNPLA1 gene [NM_001145717; exon 1]. The protein encoded by PNPLA1 acts as a unique transacylase that specifically transfers linoleic acid from triglyceride to ω-hydroxy fatty acid in ceramide, thus giving rise to ω-O-acylceramide, a particular class of sphingolipids that is essential for skin barrier function. The variant was located in the patatin core domain of PNPLA1 and resulted in a truncated protein which could disrupt the function of the protein. This case report highlights a novel compound heterozygous mutation in PNPLA1 identified in a Chinese child.


Assuntos
Ictiose Lamelar , Lipase , Humanos , Recém-Nascido , Aciltransferases/genética , Ceramidas/metabolismo , Colódio , Ictiose Lamelar/genética , Lipase/genética , Lipase/metabolismo , Mutação , Fosfolipases/genética
15.
Artigo em Inglês | WPRIM (Pacífico Ocidental) | ID: wpr-970700

RESUMO

Autosomal recessive congenital ichthyosis (ARCI) is characterized by being born as collodion babies, hyperkeratosis, and skin scaling. We described a collodion baby at birth with mild ectropion, eclabium, and syndactyly. Whole exome sequencing showed a compound heterozygous variant c.[56C>A], p.(Ser19X) and c.[100G>A], p.(Ala34Thr) in the PNPLA1 gene [NM_001145717; exon 1]. The protein encoded by PNPLA1 acts as a unique transacylase that specifically transfers linoleic acid from triglyceride to ω-hydroxy fatty acid in ceramide, thus giving rise to ω-O-acylceramide, a particular class of sphingolipids that is essential for skin barrier function. The variant was located in the patatin core domain of PNPLA1 and resulted in a truncated protein which could disrupt the function of the protein. This case report highlights a novel compound heterozygous mutation in PNPLA1 identified in a Chinese child.


Assuntos
Humanos , Recém-Nascido , Aciltransferases/genética , Ceramidas/metabolismo , Colódio , Ictiose Lamelar/genética , Lipase/metabolismo , Mutação , Fosfolipases/genética
16.
Nanoscale ; 13(47): 20034-20040, 2021 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-34842890

RESUMO

Magnetic domain structures are active electron transport agents and can be used to induce large magnetoresistance (MR), particularly in half-metallic solids. We have studied the excess resistance induced by a single magnetic domain wall in a one-dimensional half-metallic CrO2 nanoscale conductor with a built-in constriction whose channel width (d) ranges from 30 to 200 nm. We observed that the domain wall-induced MR is enhanced by 70 fold when d decreases from 200 nm to 30 nm. We speculate that the enhancement is due to the increased domain wall resistance (DWR) and the extra contribution of ballistic magnetoresistance (BMR). We have uncovered a large size effect of d on the MR induced by the domain wall, which scales with d as d-1.87±0.32. Accordingly, we predict that the MR ratio of a simple CrO2 nanowire impregnated with a constriction at a 150 nm2 cross-section could reach 100%. This large MR far exceeds that of a conventional ferromagnetic nanowire, confirming the role of half metallicity on enhanced magneto-transport.

17.
World J Clin Cases ; 9(21): 6138-6144, 2021 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-34368336

RESUMO

BACKGROUND: Encapsulating peritoneal sclerosis (EPS) is hard to diagnose because of nonspecific symptoms and signs. It is a general consensus that EPS is classified as primary and secondary. There have been several studies discovering some high-risk factors such as liver cirrhosis, of which AMA-M2 is a biomarker, and intra-abdominal surgery such as laparoscopic surgery. Imaging studies help to diagnose EPS and exploratory laparotomy might be an alternative if imaging fails. Nowadays, laparotomy plays a key role in treating EPS, especially when medical treatments do not work and medical therapy fails to ease patients' symptoms. CASE SUMMARY: A 58-year-old man complained of unexplained vomiting and abdominal distension 2 mo after laparoscopic cholecystectomy. Increased alkaline phosphatase and liver enzymes were discovered. An autoimmune liver disease test showed that AMA-M2 was positive. A gastroscopy revealed bile reflux gastritis. A magnetic resonance imaging scan showed a slight dilatation of the intrahepatic bile duct. A colonoscopy showed that there was a mucosal eminence lesion in the sigmoid colon (24 cm away from the anus), with a size of 3 cm × 3 cm and erosive surface. At last, the small intestine and the stomach were found to be encased in a cocoon-like membrane during the surgery. The membrane was dissected and adhesiolysis was done to release the trapped organs. The patient recovered and was discharged 44 d after the operation, and there was no recurrence during a follow-up period of 3 mo. CONCLUSION: AMA-M2 is a marker of primary biliary sclerosis and may help to make a preoperative diagnosis of EPS.

18.
Dalton Trans ; 50(18): 6333-6342, 2021 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-33885125

RESUMO

Hybrid electrocatalysts derived from surface self-reconstruction during reaction processes can facilitate charge transfer between different phases and nanostructures by their unique interfaces. Herein, amorphous/crystalline hybrid iron disulfide obtained by self-reconstruction is developed for the first time for the oxygen evolution reaction (OER). The amorphous/crystalline hybrid FeS2 catalyst exhibited a high OER activity with an overpotential of only 189.5 mV (IR-corrected) to deliver 10 mA cm-2 in 1.0 M KOH, which was superior to that of the commercial RuO2. Notably, in the two-electrode system with the amorphous/crystalline hybrid FeS2 as the anode electrocatalyst and Pt/C as the cathode, the catalytic activity towards the overall water splitting was enhanced with a voltage of only 1.43 V at 10 mA cm-2. The phase, composition and surface structure were changed greatly before and after the reaction. All these surface reconstructions after the OER reaction may play significant roles in the high electronic catalytic efficiency. Therefore, the study of the surface reconstruction of catalysts during the reaction process is very important for the structure-performance relationship and the design of efficient hybrid electrocatalysts.

19.
Nanoscale Adv ; 3(3): 800-804, 2021 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-36133841

RESUMO

There is widespread interest in new materials-based approaches for introducing flexibility to electromagnetic devices, such as displays, human-machine interfaces, smart textiles, and biomedical implants. From fabrication to application, incorporating ceramic components is particularly challenging due to their extreme stiffness. Here, we introduce a new approach for designing flexible ceramic films and demonstrate it by fabricating fully dense, pre-wrinkled magnetic cobalt ferrite films composed of tiled nanoplatelets. The method relies on the colloidal engineering of metalized graphene nanosheets, which are cast and compressed into wrinkled composite films with accurate control of composition and morphology. Removal of the graphene template by thermal oxidation yields free-standing cobalt ferrite films that can be stretched up to 200% and bent to radii of 2.5 mm while maintaining their magnetic properties. Magnetization retention of 73% is documented after 150% linear mechanical stretching over 100 cycles. The significant stretchability and flexibility in this hard magnetic material is achieved at near full metal oxide crystal density without addition of significant void space or a polymeric elastomer matrix.

20.
Membranes (Basel) ; 10(10)2020 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-33096651

RESUMO

Graphene oxide (GO) and its composite membranes have exhibited great potential for application in water purification and desalination. This article reports that a novel graphene oxide membrane (GOM) of ~5 µm thickness was fabricated onto a nylon membrane by vacuum filtration and cross-linked by amino acids (L-alanine, L-phenylalanine, and serine). The GOM cross-linked by amino acids (GOM-A) exhibits excellent stability, high water flux, and high rejection to metal ions. The rejection coefficients to alkali and alkaline earth metal ions through GOM-A were over 94% and 96%, respectively. The rejection coefficients decreased with an increasing H+ concentration. Metal ions (K+, Ca2+, and Fe3+) can be inserted into GOM-A layers, which enlarges the interlayer spacing of GOM-A and neutralizes the electronegativity of the membrane, resulting in the decease in the rejection coefficients to metal ions. Meanwhile, GOM-A showed quite high antibacterial efficiency against E. coli. With the excellent performance as described above, GOM-A could be used to purify and desalt water.

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