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1.
Sci Rep ; 14(1): 4597, 2024 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-38409464

RESUMO

Urea is a problematic pollutant in reclaimed water for ultrapure water (UPW) production. The sulfate radical-based advanced oxidation process (SR-AOP) has been recognized as an effective method for urea degradation. However, conventional metal-based catalysts for peroxymonosulfate (PMS) activation are unsuitable for UPW production due to issues related to metal ion leaching. In this study, the use of powdered activated carbon (PAC) was investigated for the removal of urea from reclaimed water. The PAC exhibited a high degree of defects (ID/IG = 1.709) and various surface oxygen functional groups (C-OH, C=O, and C-O), which greatly enhanced its catalytic capability. The PAC significantly facilitated PMS activation in the PMS + PAC system, leading to the complete urea decomposition. The PMS + PAC system demonstrated excellent urea removal efficiency within a wide pH range, except for pH < 3. Among the various anions present, the CO32- and PO43- inhibited urea degradation, while the coexistence of Cl- promoted urea removal. Furthermore, the feasibility test was evaluated using actual reclaimed water. The quenching test revealed that SO4-·, ·OH, and O2-· played crucial roles in the degradation of urea in the PAC-assisted SR-AOP. The oxygen functional groups (C-OH and O-C=O) and defect sites of PAC clearly contributed to PMS activation.

2.
Chemosphere ; 301: 134518, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35395257

RESUMO

Nitrophenols(NPs) are highly toxic compounds that occur in various industrial effluents. Herein, we investigated Cu nanoparticle-loaded cellulose nanofibril (CNF/PEI-Cu) aerogels as a catalyst for degrading 4-nitrophenol (4NP) in the wastewater. Non-noble metal based low-cost catalyst material and easily scalable preparation method make CNF/PEI-Cu aerogel as an appropriate catalyst for practical application in 4NP wastewater treatment. Our strategy to improve the loading amount of homogeneously distributed Cu nanoparticles was to functionalize a CNF aerogel using polyethylene imine (PEI), which can bind Cu2+ ions. Porous CNF aerogels with homogenously distributed 20-40 nm Cu nanoparticles were obtained by adsorbing Cu2+ ions and chemically reducing them to Cu metal. The FTIR, XRD, SEM, XPS and ICP-OES analysis were used to confirm the in-situ formation of Cu nanoparticles. In the presence of the CNF/PEI-Cu aerogels, 4NP was effectively reduced to 4-aminophenol (4AP) without loss of the Cu nanoparticles. The activation energy (Ea) and reaction rate constant (kapp) of the catalytic 4NP reduction reaction by the CNF/PEI2-Cu aerogels were calculated to be Ea = 39.56 kJ mol-1 and kapp = 0.770 min-1, respectively. The Ea is similar or even smaller than the Ea values of the corresponding reactions involving noble-metal catalysts, demonstrating that the CNF/PEI-Cu aerogels developed in the present study have strong potential as practical and economical catalysts.


Assuntos
Celulose , Nanopartículas Metálicas , Celulose/química , Cobre/química , Íons , Nanopartículas Metálicas/química , Metais , Nitrofenóis/química , Porosidade
3.
Nanomaterials (Basel) ; 11(8)2021 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-34443886

RESUMO

Copper in ionic form (Cu2+) should be removed from wastewater because of its harmful effects on human health. Meanwhile, Cu-metal nanoparticles (Cu0 NPs) are widely used in various applications such as catalysts, optical materials, sensors, and antibacterial agents. Here, we demonstrated the recovery of Cu2+ from wastewater and its subsequent transformation into Cu0 NPs, a value-added product, via continuous adsorption followed by chemical reduction by hydrazine. To separate and enrich Cu2+ from wastewater, a biosorbent that exhibits excellent selectivity and adsorption capacity toward Cu2+, i.e., polyethyleneimine-grafted cellulose nanofibril aerogel (PEI@CNF), was packed into a column and used to treat 20 mg/L Cu2+ wastewater at a flow rate of 5 mL/min. The Cu2+ adsorption reached equilibrium at 72 h, and the Cu2+-saturated column was eluted using 0.1 M of HCl. After five consecutive elutions of Cu2+ from the adsorbent column, a Cu2+-enriched solution with a concentration of 3212 mg/L was obtained. The recovered Cu2+ concentrate was chemically reduced to obtain Cu0 NPs by reaction with hydrazine as a reductant in the presence of sodium dodecyl sulfate (SDS) as a stabilizer. The solution pH and hydrazine/Cu2+ ratio strongly affected the reduction efficiency of Cu2+ ions. When 0.1 M of SDS was used, spherical 50-100 nm Cu0 NPs were obtained. The results demonstrate that Cu2+-spiked wastewater can be converted into Cu0 NPs as a value-added product via adsorption followed by chemical reduction.

4.
Chemosphere ; 285: 131448, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34329132

RESUMO

4-Nitrophenol (4-NP) is a hazardous aromatic compound widely used for various industries. Catalytic reduction of 4-NP using metal nanoparticles (NPs) is a highly effective method to treat 4-NP from waste effluent. Even though lots of methods have investigated to prepare efficient metal NPs composites, the nano and/or micro size of composites makes it hard to recover after wastewater treatment, limiting its practical use. Here, we fabricate 3-dimensional polyethylene imine grafted cellulose nanofibril (CNF-PEI) aerogel as a porous support material for platinum (Pt) NPs to practically and effectively treat 4-NP from wastewater. The Pt NPs are formed in-situ mode on cylindrical CNF-PEI aerogel by adsorption reaction with amine groups of PEI and subsequently reduction with NaBH4. Control of PEI grafting density and the initial concentration of Pt ions allows manipulation of the loading mass, size, and distribution of Pt NPs on 3D scaffold of CNF-PEI aerogel. The composite aerogel shows high catalytic activity for conversion of 4-NP. The 4-NP conversion activity is strongly affected by the size of Pt NPs and effective surface area of aerogels. The 2.74 nm size Pt NPs with even distribution in the aerogel show fast reaction kinetics (k = 0.12 min-1). Finally, 4-NP reduction efficiency does not decrease during 5 times reuse cycle of Pt NPs loaded CNF-PEI aerogel. This CNF-PEI aerogel loaded with Pt NPs is recovered easily from wastewater after treatment, so it is reusable and offers high potential as a practical recyclable environmental catalyst.


Assuntos
Nitrofenóis , Águas Residuárias , Catálise , Celulose
5.
J Environ Manage ; 297: 113389, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34325366

RESUMO

Radioactive cesium (137Cs) and strontium (90Sr) contaminants in seawater have been a serious problem since the Fukushima accident in 2011 due to their long-term health risks. For the effective and simultaneous removal of radioactive cesium (137Cs) and strontium (90Sr) from seawater, a Prussian blue (PB)-immobilized alginate aerogel (PB-alginate aerogel) was fabricated and its adsorption performance was evaluated. PB nanoparticles were homogeneously dispersed in the three-dimensional porous alginate aerogel matrix, which enabled facile contact with seawater. The PB-alginate aerogel exhibited Cs+ and Sr2+ adsorption capacities of 19.88 and 20.10 mg/g, respectively, without substantial interference because Cs+ and Sr2+ adsorption occurred at different adsorption sites on the composite. The Cs+ and Sr2+ adsorption onto the PB-alginate aerogel was completed within 3 h due to the highly porous morphology of the aerogel. The Cs+ and Sr2+ adsorption behaviors on the PB-alginate aerogel were systematically investigated under various conditions. Compared with Cs+ adsorption, Sr2+ adsorption onto the PB-alginate aerogel was more strongly influenced by competing cations (Na+, Mg2+, Ca2+, and K+) in seawater. 137Cs and 90Sr removal tests in real seawater demonstrated the practical feasibility of the PB-alginate aerogel as an adsorbent.


Assuntos
Alginatos , Estrôncio , Adsorção , Césio , Radioisótopos de Césio , Ferrocianetos , Água do Mar
6.
Chemosphere ; 278: 130288, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33823344

RESUMO

Heavy metal contamination in wastewater is a serious problem due to its high toxicity. In this study, three-dimensional porous and flexible polyethylene imine grafted cellulose nanofibril aerogel (PEI@CNF aerogel) is synthesized as a highly efficient biosorbent for continuous treatment of wastewater containing copper (Cu2+). The synthesized PEI@CNF aerogel efficiently separates Cu2+ from wastewater and exhibits outstanding selectivity for Cu2+ in the presence of other metal ions. The amine groups in polyethylene imine (PEI) grafted onto the porous cellulose nanofibrils (CNFs) scaffold form chelates with Cu2+ thereby effectively adsorbing Cu2+. The combination of a flexible CNF scaffold and rigid PEI results in a durable elastic matrix of the aerogel providing excellent wet stability, shape recovery property and recycle ability of PEI@CNF aerogel. Finally, in the column test, the PEI@CNF aerogel treats 88 bed volumes of wastewater containing Cu2+(∼20 mg/L). This result demonstrates that PEI@CNF aerogels are practically viable and highly efficient bio-sorbents for the treatment of wastewater containing Cu2+.


Assuntos
Nanofibras , Celulose , Cobre , Géis , Águas Residuárias
7.
Int J Med Sci ; 17(15): 2285-2291, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32922193

RESUMO

Dexmedetomidine is used for sedation during spinal anesthesia. The sympatholytic effect of dexmedetomidine may exacerbate hypotension and bradycardia with spinal anesthesia. This study investigated the effects of prophylactic intramuscular injection of ephedrine in preventing hypotension and bradycardia occurring through combined use of spinal anesthesia and dexmedetomidine. One hundred sixteen patients scheduled for lower extremity orthopedic surgery were randomized into two groups receiving either ephedrine 20 mg intramuscularly or equivalent amount of 0.9% NaCl, both with dexmedetomidine and spinal anesthesia. The primary endpoint was the incidence of hemodynamic perturbations (hypotension or bradycardia event). The secondary endpoint was a rescue doses of ephedrine and atropine. The incidence of hemodynamic perturbations was significantly lower in the ephedrine group compared with to the saline group (26.3% versus 55.9%, p = 0.001). The rescue doses of atropine (0.09 ± 0.21 versus 0.28 ± 0.41, p = 0.001) and ephedrine (1.04 ± 2.89 versus 2.03 ± 3.25, p = 0.007) were also significantly lower in the ephedrine group. There was no differences in number of patients with hypertensive (7.0% versus 11.9%, p = 0.375) or tachycardia (1.8% versus 3.4% p = 0.581) episodes. The use of ephedrine intramuscular injections may be a safe and efficacious option in preventing hemodynamic perturbations in patients who received spinal anesthesia and sedation using dexmedetomidine.


Assuntos
Raquianestesia/efeitos adversos , Bradicardia/epidemiologia , Efedrina/administração & dosagem , Hipnóticos e Sedativos/efeitos adversos , Hipotensão/epidemiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Raquianestesia/métodos , Atropina/administração & dosagem , Bradicardia/induzido quimicamente , Bradicardia/tratamento farmacológico , Bradicardia/prevenção & controle , Dexmedetomidina/efeitos adversos , Relação Dose-Resposta a Droga , Efedrina/efeitos adversos , Feminino , Hemodinâmica/efeitos dos fármacos , Humanos , Hipotensão/induzido quimicamente , Hipotensão/tratamento farmacológico , Hipotensão/prevenção & controle , Incidência , Injeções Intramusculares , Extremidade Inferior/cirurgia , Masculino , Pessoa de Meia-Idade , Procedimentos Ortopédicos/efeitos adversos , Dor Pós-Operatória/etiologia , Dor Pós-Operatória/prevenção & controle , Resultado do Tratamento , Vasoconstritores/administração & dosagem , Vasoconstritores/efeitos adversos , Adulto Jovem
8.
Org Biomol Chem ; 18(30): 5838-5842, 2020 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-32705103

RESUMO

Reactions of indigo with quinones in the presence of sodium hydride leads unexpectedly to products containing two indigo subunits; one indigo is featured in a cis configuration and fused via its indole nitrogen atoms to a second indigo at the central C-C bond of the latter. Structural, optical, and redox properties of the new compounds are reported.

9.
Carbohydr Polym ; 240: 116348, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32475599

RESUMO

Recently, graphene oxide(GO) has gained much attention for heavy metal removal due to its high surface area and lots of functional groups on the surface. However, GO itself in powder form is far away from practical adsorbents because it remains dispersed in liquid phase which causes difficulty in the separation from effluent. In this study, GO/carboxymethyl cellulose nanofibril (CMCNF) composite fiber(CF) is developed as an efficient and durable adsorbent. Cross-linked GO/CMCNF CF was continuously produced by employing Fe3+ ion as a coagulant during a typical wet-spinning process. Based on multiple interactions such as ionic bonding and electrostatic interactions between Fe3+ and carboxyl group on CMCNF, the CF exhibits enhanced mechanical property than pure GO fiber. GO/CMCNF-Fe3+ CF showed efficient lead (Pb2+) uptake with successful adsorbent recovery, which indicates durable and cost-competitive fiber type adsorbent for heavy metal ions.


Assuntos
Carboximetilcelulose Sódica/química , Grafite/química , Chumbo/isolamento & purificação , Nanofibras/química , Adsorção , Chumbo/química , Tamanho da Partícula , Propriedades de Superfície
10.
Carbohydr Polym ; 235: 115984, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32122514

RESUMO

In this study, we synthesized a Prussian blue (PB)-embedded macroporous carboxymethyl cellulose nanofibril (CMCNF) membrane for facile cesium (Cs) removal. The PB was formed in situ at Fe3+ sites on a CMCNF framework cross-linked using FeCl3 as a cross-linking agent. Cubic PB particles of size 5-20 nm were observed on the macroporous CMCNF membrane surface. The PB-CMCNF membrane showed 2.5-fold greater Cs adsorption capacity (130 mg/gPB-CMCNF) than commercial PB nanoparticles, even though the PB loading of the PB-CMCNF membrane was less than 100 mg/gPB-CMCNF. The macroporous structure of the CMCNF membrane led to improved diffusion in the solution, thereby increasing the Cs adsorption capacity. The Cs adsorption behavior was systematically investigated in different solution chemistry. Finally, 137Cs removal using a semicontinuous adsorption module was demonstrated in real seawater. The results showed that the PB-CMCNF membrane is a highly effective, practical material for the removal of 137Cs from aqueous environments.

11.
Methods Inf Med ; 59(6): 219-226, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-34261147

RESUMO

OBJECTIVES: Asthma is a heterogenous condition with significant diagnostic complexity, including variations in symptoms and temporal criteria. The disease can be difficult for clinicians to diagnose accurately. Properly identifying asthma patients from the electronic health record is consequently challenging as current algorithms (computable phenotypes) rely on diagnostic codes (e.g., International Classification of Disease, ICD) in addition to other criteria (e.g., inhaler medications)-but presume an accurate diagnosis. As such, there is no universally accepted or rigorously tested computable phenotype for asthma. METHODS: We compared two established asthma computable phenotypes: the Chicago Area Patient-Outcomes Research Network (CAPriCORN) and Phenotype KnowledgeBase (PheKB). We established a large-scale, consensus gold standard (n = 1,365) from the University of California, Los Angeles Health System's clinical data warehouse for patients 5 to 17 years old. Results were manually reviewed and predictive performance (positive predictive value [PPV], sensitivity/specificity, F1-score) determined. We then examined the classification errors to gain insight for future algorithm optimizations. RESULTS: As applied to our final cohort of 1,365 expert-defined gold standard patients, the CAPriCORN algorithms performed with a balanced PPV = 95.8% (95% CI: 94.4-97.2%), sensitivity = 85.7% (95% CI: 83.9-87.5%), and harmonized F1 = 90.4% (95% CI: 89.2-91.7%). The PheKB algorithm was performed with a balanced PPV = 83.1% (95% CI: 80.5-85.7%), sensitivity = 69.4% (95% CI: 66.3-72.5%), and F1 = 75.4% (95% CI: 73.1-77.8%). Four categories of errors were identified related to method limitations, disease definition, human error, and design implementation. CONCLUSION: The performance of the CAPriCORN and PheKB algorithms was lower than previously reported as applied to pediatric data (PPV = 97.7 and 96%, respectively). There is room to improve the performance of current methods, including targeted use of natural language processing and clinical feature engineering.


Assuntos
Asma , Processamento de Linguagem Natural , Adolescente , Algoritmos , Asma/diagnóstico , Criança , Pré-Escolar , Registros Eletrônicos de Saúde , Humanos , Classificação Internacional de Doenças , Fenótipo
12.
Carbohydr Polym ; 228: 115424, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31635723

RESUMO

Rising demand and elemental rarity requires the recycling of precious metals such as platinum group elements (PGMs). Recently, biosorption has been focused on the capability of recovering precious metals, but in practice, recycling is inefficient or far away from a closed-loop material system. Here we use a polyethylenimine (PEI)-grafted spun-fiber made of cellulose nanofibril (CNF) extracted from a tunicate as a biosorbent for PGMs. Liquid crystallinity (LC) of TCNF suspension appears to contribute the generation of well-developed open porous structure in the fiber. We show the fiber has the selectivity and high capacity of Pt (120.2 mg/g, 86%) and Pd (26.5 mg/g, 74.2%) adsorption under the presence of other metals in simulated automobile waste. The adsorbed Pt and Pd with nano-scale clusters were uniformly distributed on the porous surface, which were directly applied as a catalyst. These results propose an easy approach to recover precious metals and reuse them directly, thereby closing loops of metal recycling.

13.
PLoS One ; 14(11): e0224595, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31689320

RESUMO

BACKGROUND: Nonadherence to immunosuppressive therapy after renal transplantation is associated with poor graft outcomes. We aimed to evaluate whether the use of the Adhere4U mobile medication manager application could improve adherence among renal transplant recipients ≥1 year posttransplantation. Adhere4U can provide medication reminders, monitor medication use, and provide information on immunosuppressants. METHODS: We conducted a prospective randomized controlled study to compare the rate of nonadherence to index immunosuppressant (tacrolimus or cyclosporine) in a group using the Adhere4U app (mobile group) and in another group receiving conventional care (control group). The primary outcome was the nonadherence rate, which was evaluated using an electronic medication event monitoring system during the 6-month intervention period. Our secondary outcome included self-reported adherence using the Basel Assessment of Adherence to Immunosuppressive Medication Scale (BAASIS) and the visual analog scale (VAS) based on a 4-week recall on days 28, 90, and 180. Longitudinal data of repeated measures of self-rated adherence were analyzed using generalized estimating equations (GEE) to compare the between-group difference in adherence change over time. RESULTS: Between November 2013 and May 2015, 138 renal transplant recipients were randomly allocated to the control (n = 67) or the mobile group (n = 71). The overall nonadherence rate over the 6-month study period by electronic monitoring was 63.6%, with no between-group difference [mobile group, 65.0% (n = 39/60); control group, 62.1% (n = 36/58); odds ratio 1.14; 95% confidence interval 0.53-2.40; p = 0.89]. Self-rated nonadherence assessed using the BAASIS and VAS at baseline was 53.7% and 51.5%, respectively. Although the self-rated nonadherence by BAASIS of the mobile group was lower than the control group throughout the study period, there was no between-group difference in the change of nonadherence over time (χ2 = 2.82, df = 3, p = 0.42 by logistic GEE). There also was no significant between-group difference in the nonadherence by VAS (χ2 = 1.71, df = 3, p = 0.63 by logistic GEE) over time. The main limitation of this study was the low rate of patient engagement with the app among the mobile group. The rate of app use was 47.6% (31/65) at 28 days, 33.9% (19/56) at 90 days, and 11.5% (6/52) at 180 days. CONCLUSIONS: The Adhere4U application did not improve adherence to immunosuppressive therapy. Our evidence is limited by the high rate of attrition. Further studies on strategies to facilitate patient engagement with mobile interventions are warranted.


Assuntos
Rejeição de Enxerto/prevenção & controle , Imunossupressores/uso terapêutico , Transplante de Rim/efeitos adversos , Adesão à Medicação/estatística & dados numéricos , Aplicativos Móveis , Adolescente , Adulto , Idoso , Esquema de Medicação , Feminino , Rejeição de Enxerto/imunologia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Autorrelato/estatística & dados numéricos , Tacrolimo/uso terapêutico , Adulto Jovem
14.
ACS Nano ; 13(8): 9332-9341, 2019 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-31369239

RESUMO

Weavable sensing fibers with superior mechanical strength and sensing functionality are crucial for the realization of wearable textile sensors. However, in the fabrication of previously reported wearable sensing fibers, additional processes such as reduction, doping, and coating were essential to satisfy both requirements. The sensing fibers should be continuously synthesized in a scalable process for commercial applications with high reliability and productivity, which was challenging. In this study, we first synthesize mass-producible wearable sensing fibers with good mechanical properties and sensing functionality without additional processes by incorporating carbon nanotubes (CNTs) into distinct nanocellulose. Nanocellulose extracted from tunicate (TCNF) is homogeneously composited with single-walled CNTs, and composite fibers (TCNF/CNT) are continuously produced in aligned directions by wet spinning, facilitating liquid-crystal properties. The TCNF/CNT fibers exhibit a superior gas (NO2)-sensing performance with high selectivity and sensitivity (parts-per-billion detection). In addition, the TCNF/CNT fibers can endure complex and harsh distortions maintaining their intrinsic sensing properties and can be perfectly integrated with conventional fabrics using a direct weaving process. Our meter-scale scalable synthesis of functional composite fibers is expected to provide a mass production platform of versatile wearable sensors.


Assuntos
Técnicas Biossensoriais , Celulose/química , Nanotubos de Carbono/química , Dispositivos Eletrônicos Vestíveis , Animais , Humanos , Nanofibras/química , Óxido Nítrico/química , Óxido Nítrico/isolamento & purificação , Têxteis , Urocordados/química
15.
Int J Pharm ; 567: 118502, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31295525

RESUMO

Montmorillonite (MMT) is a highly promising material for use in drug delivery due to its high drug loading capacity and controlled drug release properties. MMT protects drug molecules between layered structure; however, drug release from MMT is sustained less than 6 h, which is insufficient for the release of antibiotics. This study sought to synthesize an antibiotic delivery material with more sustained release properties. A ciprofloxacin (CIP)-MMT composite was fabricated using carboxymethylated nanocellulose (CMCNF). A simple adsorption reaction intercalated 31.1% of CIP molecules present into the MMT under optimized conditions (pH 5, CIP = 1000 mg/L, Reaction time = 3 h). The synthesized CIP-MMT composite was fabricated using 1.5, 2, or 3 wt% CMCNF. Increasing the CMCNF content delayed the erosion of the CMCNF matrix and prevented rapid dissolution of the CIP-MMT composite. In vitro release experiments revealed that the CIP-MMT composite material provided the sustained release of CIP over 6 h. Erosion of the 3 wt% CMCNF-CIP-MMT composite occurred slowly and provided 48 h of sustained CIP release. An anti-bacterial test revealed that the 3 wt% CMCNF-CIP-MMT composite displayed the most constant antibacterial activity over 12 days. These results demonstrated that the CMCNF prepared with CIP intercalation in MMT was highly effective in prolonging the antibiotic release.


Assuntos
Antibacterianos , Bentonita , Carboximetilcelulose Sódica , Ciprofloxacina , Nanopartículas , Antibacterianos/administração & dosagem , Antibacterianos/química , Bentonita/administração & dosagem , Bentonita/química , Carboximetilcelulose Sódica/administração & dosagem , Carboximetilcelulose Sódica/química , Ciprofloxacina/administração & dosagem , Ciprofloxacina/química , Preparações de Ação Retardada/administração & dosagem , Preparações de Ação Retardada/química , Liberação Controlada de Fármacos , Nanopartículas/administração & dosagem , Nanopartículas/química , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento
16.
Carbohydr Polym ; 210: 167-174, 2019 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-30732749

RESUMO

Nanocellulose is a promising biosorbent for the recovery of precious metals from waste streams. A variety of nanocelluloses exhibit significant different properties that depend on the natural source and type. In this study, cellulose nanofibrils(P-CNF) and cellulose nanocrystals(P-CNC) obtained from hard wood pulp and CNF from tunicates(T-CNF) were evaluated for their ability to recover platinum(Pt) after modification with polyethyleneimine(PEI). The PEI grafting density on each nanocellulose was distinct, resulting in significant variations in the Pt adsorption performance. The Pt adsorption capacity of the PEI-modified nanocelluloses followed the order T-CNF>>P-CNC > P-CNF. The inherent characteristics of T-CNF, that is, the negative charge and high surface area caused by open porous structure, were found attributed to the grafting of ≈40% PEI and the excellent Pt adsorption capacity(≈600 mg/g). Also PEI-modified T-CNF exhibited high selectivity towards Pt in the presence of other metals. Finally, PEI modified T-CNF was applied for Pt recovery from simulated spent automobile catalyst leachate to prove feasibility in a real application.

17.
Carbohydr Polym ; 195: 136-142, 2018 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-29804961

RESUMO

Polyurethane (PU) foam was utilized as an efficient and durable template to immobilize surface-functionalized nanocellulose, carboxymethylated cellulose nanofibrils (CMCNFs), to address some of the challenges for the application of nanocellulose to industrial water purification, such as its agglomeration, difficulties in separation from effluent, and regeneration. The composite foams exhibited well dispersed CMCNFs in PU matrices with open pore structure; the hydrogen bonds result in the enhancement of mechanical strength, which is another requirement of ideal adsorbents for wastewater treatment. The composite foams show high adsorption capacity and the potential for recyclability. The combination of optimal surface modification of nanocellulose with isolation and immobilization in durable PU foam achieved an efficient and cost-competitive bio-sorbent for heavy metal ions.

18.
J Environ Manage ; 205: 192-200, 2018 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-28985598

RESUMO

Alginate bead is a promising strontium (Sr) adsorbent in seawater, but highly concentrated Na ions caused over-swelling and damaged the hydrogel bead. To improve the mechanical stability of alginate bead, flexible foam-type zeolite-alginate composite was synthesized and Sr adsorption performance was evaluated in seawater; 1-10% zeolite immobilized alginate foams were prepared by freeze-dry technique. Immobilization of zeolite into alginate foam converted macro-pores to meso-pores which lead to more compact structure. It resulted in less swollen composite in seawater medium and exhibited highly improved mechanical stability compared with alginate bead. Besides, Sr adsorption efficiency and selectivity were enhanced by immobilization of zeolite in alginate foam due to the increase of Sr binding sites (zeolite). In particular, Sr selectivity against Na was highly improved. The 10% zeolite-alginate foam exhibited a higher log Kd of 3.3, while the pure alginate foam exhibited 2.7 in the presence of 0.1 M Na. Finally, in the real seawater, the 10% zeolite-alginate foam exhibited 1.5 times higher Sr adsorption efficiency than the pure alginate foam. This result reveals that zeolite-alginate foam composite is appropriate material for Sr removal in seawater due to its swelling resistance as well as improved Sr adsorption performance in complex media.


Assuntos
Radioisótopos de Estrôncio , Zeolitas , Adsorção , Alginatos , Ácido Glucurônico , Ácidos Hexurônicos , Água do Mar , Estrôncio
19.
Chemosphere ; 165: 231-238, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27657815

RESUMO

In this study, a highly stable alginate/Fe3O4 composite was synthesized, and systematically investigated for the practical application of strontium (Sr) removal in complex media, such as seawater and radioactive wastewater. To overcome the drawbacks of the use of alginate microspheres, high contents of alginic acid and Fe3O4 were used to provide a more rigid structure with little swelling and facile separation, respectively. The synthesized composite was optimized for particle sizes of <400 µm and 1% content of Fe3O4. The alginate/Fe3O4 composite showed excellent Sr uptake (≈400.0 mg/g) and exhibited outstanding selectivity for Sr among various cations (Na, Mg, Ca and K). However, in diluted Sr condition (50 mg/L), Ca significantly affected Sr adsorption, resulting in a decrease of Kd value from 3.7 to 2.4 at the 0.01 M Ca. The alginate/Fe3O4 composite could be completely regenerated using 0.1 M HCl and CaCl2. In real seawater spiked with 50 mg/L of Sr, the alginate/Fe3O4 composite showed 12.5 mg/g of Sr uptake, despite the highly concentrated ions in seawater. The adsorption experiment for radio-active 90Sr revealed a removal efficiency of 67% in real seawater, demonstrating the reliability of the alginate/Fe3O4 composite.


Assuntos
Compostos Férricos/química , Água do Mar/química , Radioisótopos de Estrôncio/metabolismo , Estrôncio/isolamento & purificação , Águas Residuárias/química , Purificação da Água/métodos , Adsorção , Alginatos/química , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Microesferas , Tamanho da Partícula , Reprodutibilidade dos Testes , Estrôncio/química , Radioisótopos de Estrôncio/química
20.
Cancer Immunol Immunother ; 65(1): 61-72, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26613952

RESUMO

Myeloid-derived suppressor cells (MDSCs) are one of the most important cell types that contribute to negative regulation of immune responses in the tumor microenvironment. Recently, aminoacyl-tRNA synthetase-interacting multifunctional protein 1 (AIMP1), a novel pleiotropic cytokine, was identified as an antitumor protein that inhibits angiogenesis and induces antitumor responses. However, the effect of AIMP1 on MDSCs in the tumor environment remains unclear. In the present study, we demonstrated that AIMP1 significantly inhibited tumor growth in 4T1 breast cancer-bearing mice and reduced MDSCs population of tumor sites and spleens of tumor-bearing mice. AIMP1 reduced expansion of MDSCs from bone marrow-derived cells in the tumor-conditioned media. AIMP1 also negatively regulated suppressive activities of MDSCs by inhibiting IL-6 and NO production, and Arg-1 expression. Furthermore, treatment of breast cancer-bearing mice with AIMP1 decreased the capacity of MDSCs to suppress T cell proliferation and Treg cell induction. Western blot and inhibition experiments showed that downregulation of MDSCs functions by AIMP1 may result from attenuated activation of STATs, Akt, and ERK. These findings indicate that AIMP1 plays an essential role in negative regulation of suppressive functions of MDSCs. Therefore, it has a significant potential as a therapeutic agent for cancer treatment.


Assuntos
Aminoacil-tRNA Sintetases/imunologia , Apresentação de Antígeno/imunologia , Neoplasias da Mama/imunologia , Células Mieloides/imunologia , Animais , Linhagem Celular Tumoral , Proliferação de Células , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C
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