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1.
Aquat Toxicol ; 271: 106934, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38728926

RESUMO

Microplastics (MP) and antibiotics coexist in the environment and their combined exposure represents a source of increasing concern. MP may act as carriers of antibiotics because of their sorption capacity. Knowledge of the interactions between them may help improve understanding of their migration and transformation. In this work, the adsorption behaviour of a group of sulfonamides and their acetylated metabolites on different sizes of polyamide (PA) and polystyrene (PS) MP were investigated and compared. Sulfonamides were adsorbed on both MP (qmax up to 0.699 and 0.184 mg/g, for PA and PS, respectively) fitting to a linear isotherm model (R2 > 0.835). A low particle size and an acidic and salinity medium significantly enhances the adsorption capacity of sulfonamides (i.e. removal of sulfamethoxazole increased from 8 % onto 3 mm PA pellets to 80 % onto 50 mm of PA pellets). According to characterization results, adsorption mechanism is explained by pore filling and hydrogen bonds (for PA) and hydrophobic interactions (for PS). After adsorption, surface area was increased in both MP as result of a potential ageing of the particles and the intensity of XRD peaks was higher denoting a MP structure more amorphized. Metabolites were adsorbed more efficiently than their parent compounds on PS while the opposite effect was observed on PA explained by the acetylation of the amine group and, subsequently the reduction of hydrogen bond interactions. Although the dissolved organic matter inhibits sulfonamides adsorption, removal up to 65.2 % in effluent wastewater and up to 72.1 % in surface water were observed in experiments using real matrices denoting the role of MP as vectors of sulfonamide antibiotics in aquatic media.


Assuntos
Antibacterianos , Microplásticos , Nylons , Poliestirenos , Sulfonamidas , Poluentes Químicos da Água , Poluentes Químicos da Água/química , Poliestirenos/química , Adsorção , Antibacterianos/química , Sulfonamidas/química , Nylons/química , Microplásticos/química , Tamanho da Partícula
2.
ACS Appl Mater Interfaces ; 16(19): 25304-25316, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38654450

RESUMO

Poly(vinyl alcohol) (PVA) hydrogels are water-rich, three-dimensional (3D) network materials that are similar to the tissue structure of living organisms. This feature gives hydrogels a wide range of potential applications, including drug delivery systems, articular cartilage regeneration, and tissue engineering. Due to the large amount of water contained in hydrogels, achieving hydrogels with comprehensive properties remains a major challenge, especially for isotropic hydrogels. This study innovatively prepares a multiscale-reinforced PVA hydrogel from molecular-level coupling to nanoscale enhancement by chemically cross-linking poly(vinylpyrrolidone) (PVP) and in situ assembled aromatic polyamide nanofibers (ANFs). The optimized ANFs-PVA-PVP (APP) hydrogels have a tensile strength of ≈9.7 MPa, an elongation at break of ≈585%, a toughness of ≈31.84 MJ/m3, a compressive strength of ≈10.6 MPa, and a high-water content of ≈80%. It is excellent among all reported PVA hydrogels and even comparable to some anisotropic hydrogels. System characterizations show that those performances are attributed to the particular multiscale load-bearing structure and multiple interactions between ANFs and PVA. Moreover, APP hydrogels exhibit excellent biocompatibility and a low friction coefficient (≈0.4). These valuable performances pave the way for broad potential in many advanced applications such as biological tissue replacement, flexible wearable devices, electronic skin, and in vivo sensors.


Assuntos
Materiais Biocompatíveis , Hidrogéis , Nanofibras , Álcool de Polivinil , Povidona , Nanofibras/química , Álcool de Polivinil/química , Hidrogéis/química , Povidona/química , Materiais Biocompatíveis/química , Animais , Camundongos , Nylons/química , Resistência à Tração , Teste de Materiais , Força Compressiva
3.
World J Gastroenterol ; 30(9): 1143-1153, 2024 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-38577185

RESUMO

BACKGROUND: Endoscopic full-thickness resection (EFTR) of gastric submucosal tumors (SMTs) is safe and effective; however, postoperative wound management is equally important. Literature on suturing following EFTR for large (≥ 3 cm) SMTs is scarce and limited. AIM: To evaluate the efficacy and clinical value of double-nylon purse-string suture in closing postoperative wounds following EFTR of large (≥ 3 cm) SMTs. METHODS: We retrospectively analyzed the data of 85 patients with gastric SMTs in the fundus of the stomach or in the lesser curvature of the gastric body whose wounds were treated with double-nylon purse-string sutures after successful tumor resection at the Endoscopy Center of Renmin Hospital of Wuhan University. The operative, postoperative, and follow-up conditions of the patients were evaluated. RESULTS: All tumors were completely resected using EFTR. 36 (42.35%) patients had tumors located in the fundus of the stomach, and 49 (57.65%) had tumors located in the body of the stomach. All patients underwent suturing with double-nylon sutures after EFTR without laparoscopic assistance or further surgical treatment. Postoperative fever and stomach pain were reported in 13 (15.29%) and 14 (16.47%) patients, respectively. No serious adverse events occurred during the intraoperative or postoperative periods. A postoperative review of all patients revealed no residual or recurrent lesions. CONCLUSION: Double-nylon purse-string sutures can be used to successfully close wounds that cannot be completely closed with a single nylon suture, especially for large (≥ 3 cm) EFTR wounds in SMTs.


Assuntos
Ressecção Endoscópica de Mucosa , Neoplasias Gástricas , Humanos , Nylons , Gastroscopia/efeitos adversos , Estudos Retrospectivos , Neoplasias Gástricas/patologia , Suturas , Resultado do Tratamento
5.
AAPS PharmSciTech ; 25(4): 69, 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38538972

RESUMO

Thymoquinone (TQ) is a phytochemical compound present in Nigella sativa and has potential benefits for treating dermatological conditions such as psoriasis. However, its clinical use is limited due to its restricted bioavailability, caused mainly by its low solubility and permeability. To overcome this, a new transdermal drug delivery system is required. Nanoparticles are known to enhance material solubility and permeability, and hence, this study aimed to synthesize TQ-loaded L-arginine-based polyamide (TQ/Arg PA) nanocapsules incorporated into transdermal patches for prolonged delivery of TQ. To achieve this, Eudragit E polymer, plasticizers, and aloe vera as penetration enhancer were used to develop the transdermal patch. Furthermore, novel TQ/Arg-PA was synthesized via interfacial polymerization, and the resultant nanocapsules (NCs) were incorporated into the matrix transdermal patch. The Arg-PA NCs' structure was confirmed via NMR and FTIR, and optimal TQ/Arg-PA NCs containing formulation showed high entrapment efficiency of TQ (99.60%). Molecular and thermal profiling of TQ/Arg-PA and the transdermal patch revealed the effective development of spherical NCs with an average particle size of 129.23 ± 18.22 nm. Using Franz diffusion cells and synthetic membrane (STRAT M®), the in vitro permeation profile of the prepared patches demonstrated an extended release of TQ over 24 h, with enhanced permeation by 42.64% when aloe vera was employed. In conclusion, the produced formulation has a potential substitute for corticosteroids and other drugs commonly used to treat psoriasis due to its effectiveness, safety, and lack of the side effects typically associated with other drugs.


Assuntos
Benzoquinonas , Nanocápsulas , Psoríase , Humanos , Nanocápsulas/química , Nylons , Adesivo Transdérmico , Psoríase/tratamento farmacológico
6.
Environ Sci Technol ; 58(14): 6359-6369, 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38512318

RESUMO

There is only sparse empirical data on the settling velocity of small, nonbuoyant microplastics thus far, although it is an important parameter governing their vertical transport within aquatic environments. This study reports the settling velocities of 4031 exemplary microplastic particles. Focusing on the environmentally most prevalent particle shapes, irregular microplastic fragments of four different polymer types (9-289 µm) and five discrete length fractions (50-600 µm) of common nylon and polyester fibers are investigated, respectively. All settling experiments are carried out in quiescent water by using a specialized optical imaging setup. The method has been previously validated in order to minimize disruptive factors, e.g., thermal convection or particle interactions, and thus enable the precise measurements of the velocities of individual microplastic particles (0.003-9.094 mm/s). Based on the obtained data, ten existing models for predicting a particle's terminal settling velocity are assessed. It is concluded that models, which were specifically deduced from empirical data on larger microplastics, fail to provide accurate predictions for small microplastics. Instead, a different approach is highlighted as a viable option for computing settling velocities across the microplastics continuum in terms of size, density, and shape.


Assuntos
Microplásticos , Poluentes Químicos da Água , Plásticos , Nylons , Água , Poluentes Químicos da Água/análise , Monitoramento Ambiental/métodos
7.
Environ Pollut ; 348: 123792, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38518974

RESUMO

The production and consumption of disposable face masks (DFMs) increased intensely during the COVID-19 pandemic, leading to a high amount of them being found in the terrestrial and aquatic environment. The main goal of this research study is to conduct a comparative evaluation of the water-leachability of microplastics (MPs) and chemical additives from various types of disposable surgical/medical face masks (MM DFMs) and filtering face pieces (FFPs). Fourier-Transform Infrared Spectroscopy was used for MPs analysis. Liquid Chromatography/High Resolution Mass Spectrometry was used to analyse analytes presented in the water-leachates of DFMs. FFPs released 3-4 times more microplastic particles compared to MM DFMs. The release of MPs into water from all tested DFMs without mechanical stress suggests potential MP contamination originating from the DFM production process. Our study for the first time identified bisphenol B (0.25-0.42 µg/L) and 1,4-bis(2-ethylhexyl) sulfosuccinate (163.9-115.0 µg/L) as leachables from MM DFMs. MPs in the water-leachates vary in size, with predominant particles <100 µm, and the release order from DFMs is MMIIR > MMII > FFP3>FFP2>MMI. The main type of microplastics identified in the water leachates of the investigated face masks was polypropylene, accounting for 93-97% for MM DFMs and 82-83% for FFPs. Other polymers such as polyethylene, polycarbonate, polyester/polyethylene terephthalate, polyamide/Nylon, polyvinylchloride, and ethylene-propylene copolymer were also identified, but in smaller amounts. FFPs released a wider variety and a higher percentage (17-18%) of other polymers compared to MM DFMs (3-7%). Fragments and fibres were identified in all water-leachate samples, and fragments, particularly debris of polypropylene fibres, were the most common MP morphotype. The findings in this study are important in contributing additional data to develop science-based policy recommendations on the health and environmental impacts of MPs and associated chemical additives originated from DFMs.


Assuntos
Microplásticos , Poluentes Químicos da Água , Humanos , Plásticos , Máscaras , Pandemias , Polipropilenos , Nylons , Água , Monitoramento Ambiental
8.
Wound Repair Regen ; 32(3): 229-233, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38534045

RESUMO

The capability to produce suture material using three-dimensional (3D) printing technology may have applications in remote health facilities where rapid restocking of supplies is not an option. This is a feasibility study evaluating the usability of 3D-printed sutures in the repair of a laceration wound when compared with standard suture material. The 3D-printed suture material was manufactured using a fused deposition modelling 3D printer and nylon 3D printing filament. Study participants were tasked with performing laceration repairs on the pigs' feet, first with 3-0 WeGo nylon suture material, followed by the 3D-printed nylon suture material. Twenty-six participants were enrolled in the study. Survey data demonstrated statistical significance with how well the 3D suture material performed with knot tying, 8.9 versus 7.5 (p = 0.0018). Statistical significance was observed in the 3D-printed suture's ultimate tensile strength when compared to the 3-0 Novafil suture (274.8 vs. 199.8 MPa, p = 0.0096). The 3D-printed suture also demonstrated statistical significance in ultimate extension when compared to commercial 3-0 WeGo nylon suture (49% vs. 37%, p = 0.0215). This study was successful in using 3D printing technology to manufacture suture material and provided insight into its usability when compared to standard suture material.


Assuntos
Estudos de Viabilidade , Impressão Tridimensional , Técnicas de Sutura , Suturas , Resistência à Tração , Animais , Suínos , Lacerações/cirurgia , Teste de Materiais , Nylons , Cicatrização , Humanos , Modelos Animais de Doenças
9.
J Dent ; 145: 104922, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38490322

RESUMO

OBJECTIVES: The aim was to collect different clinical parameters systematically and proactively regarding safety, effectiveness, and performance of a nylon monofilament suture under routine clinical practice for oral surgery. METHODS: The study design was prospective, bicentric, international, single-armed, and observational. A non-absorbable suture was applied to close the mucosa after different dental surgical interventions. Main objective was the incidence of combined postoperative complications until suture removal. The 95 % Confidence Interval (Agresti-Coull method) was used to prove the non-inferiority with a pre-specified upper margin of 21.9 %. Secondary variables were intraoperative suture handling, patient pain and satisfaction, wound healing, aesthetic appearance, and bacterial contamination. RESULTS: 105 patients were enrolled. Complication rate was low (1.9 %), 2 swellings occurred. Pain was present for 1.61 days ± 1.42 after various dental interventions with an average pain level of 20.98 ± 22.60 (VAS). Patients with impacted third molar extraction showed the longest pain duration (6 days) combined with the highest mean pain level of 35.33 ± 30.45 (VAS). Intraoperative suture handling was very good to excellent. Suture removal was done after an average duration of 7.56 ± 2.09 days. Patient's satisfaction was high, and an excellent wound healing was reported by the dentists. Aesthetic appearance only performed in implant patients was rated by oral surgeons with an average of 96.19 ± 3.79 points [min. 80 - max. 100] at 5 months postoperatively. Thread bacterial analysis showed that F. nucleatum was the most present species. CONCLUSIONS: Our findings indicate that the non-absorbable, nylon-based monofilament suture used is safe and quite suitable for oral mucosal closure after various dental surgical interventions such as tooth extraction, implant placement and impacted third molar extraction. CLINICAL SIGNIFICANCE: This study showed the safe use of a non-absorbable, nylon-based monofilament suture for different oral surgical interventions under daily routine clinical practice.


Assuntos
Mucosa Bucal , Nylons , Técnicas de Sutura , Suturas , Cicatrização , Humanos , Estudos Prospectivos , Feminino , Masculino , Adulto , Pessoa de Meia-Idade , Mucosa Bucal/microbiologia , Mucosa Bucal/cirurgia , Procedimentos Cirúrgicos Bucais/métodos , Complicações Pós-Operatórias , Satisfação do Paciente , Adulto Jovem , Idoso , Adolescente , Extração Dentária , Dor Pós-Operatória , Dente Serotino/cirurgia , Estudos de Coortes , Resultado do Tratamento
10.
Clin Oral Investig ; 28(4): 211, 2024 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-38480601

RESUMO

OBJECTIVES: The objective of this single-use, five-treatment, five-period, cross-over randomized controlled trial (RCT) was to compare the efficacy in dental plaque removal of a new Y-shaped automatic electric toothbrush (Y-brush) compared to a U-shaped automatic electric toothbrush (U-brush), a manual toothbrushing procedure (for 45 and 120 s), and no brushing (negative control). MATERIALS AND METHODS: Eligible participants were volunteer students randomized to the treatments in the five periods of the study. The primary outcome measure was the reduction in full-mouth plaque score (FMPS) after brushing while the secondary outcome variable was a visual analogic scale (VAS) on subjective clean mouth sensation. Mixed models were performed for difference in FMPS and VAS. RESULTS: After brushing procedures, manual toothbrushing (120 s) showed a statistically significant reduction in FMPS than Y-brush (difference 36.9; 95%CI 29.6 to 44.1, p < 0.0001), U-brush (difference 42.3; 95%CI 35.1 to 49.6, p < 0.0001), manual brushing (45 s) (difference 13.8; 95%CI 6.5 to 21.1, p < 0.0001), and No brushing (difference 46.6; 95%CI 39.3 to 53.9, p < 0.0001). Y-brush was significantly more effective than No brushing (difference 9.8; 95%CI 2.5 to 17.0, p = 0.0030), while there was no significant difference compared to U- brush. Similar results were obtained for the differences in the Clean Mouth VAS. CONCLUSIONS: Y-brush was significantly more effective than no brushing (negative control) in removing dental plaque. When compared to manual toothbrushing for both 45 and 120 s, however, Y-brush was less effective in dental plaque removal. CLINICAL RELEVANCE: Modified design of automatic toothbrushing devices could improve plaque reduction, especially in patients with intellectual disabilities or motor difficulties.


Assuntos
Placa Dentária , Succinimidas , Escovação Dentária , Humanos , Nylons , Placa Dentária/terapia , Desenho de Equipamento , Índice de Placa Dentária , Método Simples-Cego , Estudos Cross-Over
11.
Water Res ; 254: 121397, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38461599

RESUMO

Municipal wastewater treatment plants (WWTPs) play a crucial role in the collection and redistribution of plastic particles from both households and industries, contributing to their presence in the environment. Previous studies investigating the levels of plastics in WWTPs, and their removal rates have primarily focused on polymer type, size, shape, colour, and particle count, while comprehensive understanding of the mass concentration of plastic particles, particularly those <1 µm (nanoplastics), remains unclear and lacking. In this study, pyrolysis gas chromatography-mass spectrometry was used to simultaneously determine the mass concentration of nine selected polymers (i.e., polyethylene (PE), polypropylene (PP), polystyrene (PS), poly(ethylene terephthalate) (PET), nylon 6, nylon 66, polyvinylchloride (PVC), poly(methyl methacrylate) (PMMA) and polycarbonate (PC)) below 1 µm in size across the treatment processes or stages of three WWTPs in Australia. All the targeted nanoplastics were detected at concentrations between 0.04 and 7.3 µg/L. Nylon 66 (0.2-7.3 µg/L), PE (0.1-6.6 µg/L), PP (0.1-4.5 µg/L), Nylon 6 (0.1-3.6 µg/L) and PET (0.1-2.2 µg/L), were the predominant polymers in the samples. The mass concentration of the total nanoplastics decreased from 27.7, 18 and 9.1 µg/L in the influent to 1, 1.4 and 0.8 µg/L in the effluent, with approximate removal rates of 96 %, 92 % and 91 % in plants A, B and C, respectively. Based on annual wastewater effluent discharge, it is estimated that approximately 24, 2 and 0.7 kg of nanoplastics are released into the environment per year for WWTPs A, B and C, respectively. This study investigated the mass concentrations and removal rates of nanoplastics with a size range of 0.01-1 µm in wastewater, providing important insight into the pollution levels and distribution patterns of nanoplastics in Australian WWTPs.


Assuntos
Caprolactama/análogos & derivados , Polímeros , Poluentes Químicos da Água , Purificação da Água , Águas Residuárias , Microplásticos , Nylons , Pirólise , Cromatografia Gasosa-Espectrometria de Massas , Austrália , Plásticos/análise , Polipropilenos/análise , Polimetil Metacrilato , Polietilenos , Poluentes Químicos da Água/química , Monitoramento Ambiental
12.
Environ Sci Technol ; 58(13): 5878-5888, 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38498471

RESUMO

Data-driven machine learning (ML) provides a promising approach to understanding and predicting the rejection of trace organic contaminants (TrOCs) by polyamide (PA). However, various confounding variables, coupled with data scarcity, restrict the direct application of data-driven ML. In this study, we developed a data-knowledge codriven ML model via domain-knowledge embedding and explored its application in comprehending TrOC rejection by PA membranes. Domain-knowledge embedding enhanced both the predictive performance and the interpretability of the ML model. The contribution of key mechanisms, including size exclusion, charge effect, hydrophobic interaction, etc., that dominate the rejections of the three TrOC categories (neutral hydrophilic, neutral hydrophobic, and charged TrOCs) was quantified. Log D and molecular charge emerge as key factors contributing to the discernible variations in the rejection among the three TrOC categories. Furthermore, we quantitatively compared the TrOC rejection mechanisms between nanofiltration (NF) and reverse osmosis (RO) PA membranes. The charge effect and hydrophobic interactions possessed higher weights for NF to reject TrOCs, while the size exclusion in RO played a more important role. This study demonstrated the effectiveness of the data-knowledge codriven ML method in understanding TrOC rejection by PA membranes, providing a methodology to formulate a strategy for targeted TrOC removal.


Assuntos
Nylons , Purificação da Água , Osmose , Purificação da Água/métodos , Membranas Artificiais , Filtração
13.
J Mater Chem B ; 12(14): 3509-3520, 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38516824

RESUMO

Both chemodynamic therapy and photodynamic therapy, based on the production of reactive oxygen (ROS), have excellent potential in cancer therapy. However, the abnormal redox homeostasis in tumor cells, especially the overexpressed glutathione (GSH) could scavenge ROS and reduce the anti-tumor efficiency. Therefore, it is essential to develop a simple and effective tumor-specific drug delivery system for modulating the tumor microenvironment (TME) and achieving synergistic therapy at the tumor site. In this study, self-assembled nanoparticles (named CDZP NPs) were developed using copper ion (Cu2+), doxorubicin (Dox), zinc phthalocyanine (ZnPc) and a trace amount of poly(2-(di-methylamino)ethylmethacrylate)-poly[(R)-3-hydroxybutyrate]-poly(2-(dimethylamino)ethylmethacrylate) (PDMAEMA-PHB-PDMAEMA) through chelation, π-π stacking and hydrophobic interaction. These triple factor-responsive (pH, laser and GSH) nanoparticles demonstrated unique advantages through the synergistic effect. Highly controllable drug release ensured its effectiveness at the tumor site, Dox-induced chemotherapy and ZnPc-mediated fluorescence (FL) imaging exhibited the distribution of nanoparticles. Meanwhile, Cu2+-mediated GSH-consumption not only reduced the intracellular ROS elimination but also produced Cu+ to catalyze hydrogen peroxide (H2O2) and generated hydroxyl radicals (˙OH), thereby enhancing the chemodynamic and photodynamic therapy. Herein, this study provides a green and relatively simple method for preparing multifunctional nanoparticles that can effectively modulate the TME and improve synergetic cancer therapy.


Assuntos
Metacrilatos , Metilmetacrilatos , Nanopartículas , Neoplasias , Nylons , Humanos , Cobre/uso terapêutico , Espécies Reativas de Oxigênio , Peróxido de Hidrogênio/uso terapêutico , Nanopartículas/química , Doxorrubicina/farmacologia , Doxorrubicina/uso terapêutico , Neoplasias/tratamento farmacológico , Glutationa/química , Oxirredução , Microambiente Tumoral
14.
Environ Sci Technol ; 58(14): 6435-6443, 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38551393

RESUMO

Nanovoids within a polyamide layer play an important role in the separation performance of thin-film composite (TFC) reverse osmosis (RO) membranes. To form more extensive nanovoids for enhanced performance, one commonly used method is to incorporate sacrificial nanofillers in the polyamide layer during the exothermic interfacial polymerization (IP) reaction, followed by some post-etching processes. However, these post-treatments could harm the membrane integrity, thereby leading to reduced selectivity. In this study, we applied in situ self-etchable sacrificial nanofillers by taking advantage of the strong acid and heat generated in IP. CaCO3 nanoparticles (nCaCO3) were used as the model nanofillers, which can be in situ etched by reacting with H+ to leave void nanostructures behind. This reaction can further degas CO2 nanobubbles assisted by heat in IP to form more nanovoids in the polyamide layer. These nanovoids can facilitate water transport by enlarging the effective surface filtration area of the polyamide and reducing hydraulic resistance to significantly enhance water permeance. The correlations between the nanovoid properties and membrane performance were systematically analyzed. We further demonstrate that the nCaCO3-tailored membrane can improve membrane antifouling propensity and rejections to boron and As(III) compared with the control. This study investigated a novel strategy of applying self-etchable gas precursors to engrave the polyamide layer for enhanced membrane performance, which provides new insights into the design and synthesis of TFC membranes.


Assuntos
Incrustação Biológica , Nanopartículas , Osmose , Nylons/química , Gravuras e Gravação , Membranas Artificiais , Água/química
15.
Methods ; 225: 20-27, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38471600

RESUMO

Aberrant gene expression underlies numerous human ailments. Hence, developing small molecules to target and remedy dysfunctional gene regulation has been a long-standing goal at the interface of chemistry and medicine. A major challenge for designing small molecule therapeutics aimed at targeting desired genomic loci is the minimization of widescale disruption of genomic functions. To address this challenge, we rationally design polyamide-based multi-functional molecules, i.e., Synthetic Genome Readers/Regulators (SynGRs), which, by design, target distinct sequences in the genome. Herein, we briefly review how SynGRs access chromatin-bound and chromatin-free genomic sites, then highlight the methods for the study of chromatin processes using SynGRs on positioned nucleosomes in vitro or disease-causing repressive genomic loci in vivo.


Assuntos
Cromatina , Nucleossomos , Humanos , Cromatina/genética , Cromatina/metabolismo , Nucleossomos/genética , Nucleossomos/metabolismo , Nylons/química , Nylons/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Animais , Montagem e Desmontagem da Cromatina/efeitos dos fármacos , Montagem e Desmontagem da Cromatina/genética , Genômica/métodos
16.
Int J Biol Macromol ; 267(Pt 1): 129256, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38493823

RESUMO

In the present study, the commercially available three different fabrics cotton, nylon and cotton/nylon were modified by chitosan and silver nanoparticles using a crosslinker triethyl orthoformate (TEOF). Resulted cotton­silver (Ag-Cs-Cot), nylon­silver (Ag-Cs-Nyl) and cotton-nylon silver (Ag-Cs-Cot-Nyl) fabrics showed significant anti-bacterial activity even after 50 washing cycles. Silver nanoparticles were prepared by reducing silver nitrate through sodium borohydride at 0 °C. In FTIR spectra the peak at near 1650 cm-1 confirmed that TEOF mediated attachment of chitosan with fabrics (due to C=N) and the stretching of secondary amine near the 3375 cm-1 indicated the silver attachment to the amine group of the chitosan. In Scanning Electron Microscope (SEM) images smooth surfaces of fabrics without any damage by modification process were observed. The antibacterial activity was Analyzed by agar diffusion and broth dilution assays against Escherichia coli and Staphylococcus aureus bacterial strains and results showed 90% bacterial inhibition against E. coli and 89% bacterial inhibition against S. aureus. For testing the antibacterial durability, the modified fabrics were washed with non-ionic detergent (10g/l) for 15 minutes under aggressive stirring (100 rpm) at room temperature. The modified fabrics retained antibacterial activity over the 50 washing cycles. Finally, the commercial potential of cotton-silver fabric was evaluated by stitching it with the socks of football players and interestingly results showed that the modified fabric on the socks showed more than 90% bacterial inhibition as compared to the plain fabric after 70 minutes of playing activity.


Assuntos
Antibacterianos , Quitosana , Fibra de Algodão , Escherichia coli , Nanopartículas Metálicas , Nylons , Prata , Staphylococcus aureus , Têxteis , Quitosana/química , Quitosana/farmacologia , Prata/química , Prata/farmacologia , Nanopartículas Metálicas/química , Antibacterianos/farmacologia , Antibacterianos/química , Nylons/química , Escherichia coli/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Formiatos/química
17.
Environ Sci Technol ; 58(11): 5174-5185, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38451543

RESUMO

Nanofiltration (NF) has the potential to achieve precise ion-ion separation at the subnanometer scale, which is necessary for resource recovery and a circular water economy. Fabricating NF membranes for selective ion separation is highly desirable but represents a substantial technical challenge. Dipole-dipole interaction is a mechanism of intermolecular attractions between polar molecules with a dipole moment due to uneven charge distribution, but such an interaction has not been leveraged to tune membrane structure and selectivity. Herein, we propose a novel strategy to achieve tunable surface charge of polyamide membrane by introducing polar solvent with a large dipole moment during interfacial polymerization, in which the dipole-dipole interaction with acyl chloride groups of trimesoyl chloride (TMC) can successfully intervene in the amidation reaction to alter the density of surface carboxyl groups in the polyamide selective layer. As a result, the prepared positively charged (PEI-TMC)-NH2 and negatively charged (PEI-TMC)-COOH composite membranes, which show similarly high water permeance, demonstrate highly selective separations of cations and anions in engineering applications, respectively. Our findings, for the first time, confirm that solvent-induced dipole-dipole interactions are able to alter the charge type and density of polyamide membranes and achieve tunable surface charge for selective and efficient ion separation.


Assuntos
Cloretos , Nylons , Cloretos/química , Nylons/química , Membranas Artificiais , Solventes , Água
18.
Environ Int ; 185: 108536, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38471263

RESUMO

This study investigated the impacts of light irradiation and polymer types on the leaching behavior of dissolved organic matter (DOM) from microplastics (MPs) in freshwater. Polypropylene had the highest leaching capacity of DOM after photoaging, followed by polystyrene (PS), polyamide (PA) and polyethylene terephthalate (PET). While similarly low levels of DOM were observed in the remaining 5 MP suspensions under UV irradiation and in almost all MP suspensions (except PA) under darkness. These suggest that the photooxidation of some buoyant plastics may influence the carbon cycling of nature waters. Among 9 MP-derived leachates, PET leachates had the highest chromophoric DOM concentration and aromaticity, probably owing to the special benzene rings and carbonyl groups in PET structures and its fast degradation rate. Protein-like substances were the primary fluorescent DOM in MP suspensions (except PS), especially in darkness no other fluorescent substances were found. Considering the bio-labile properties of proteins together, MPs regardless of floating or suspended in an aquatic environment may have prevalent long-term effects on microbial activities. Besides, from monomers to hexamers with newly formed chemical bonds were identified in UV-irradiated MP suspensions. These results will contribute to a deep insight into the potential ecological effects related to MP degradation.


Assuntos
Microplásticos , Plásticos , Polímeros , Matéria Orgânica Dissolvida , Poliestirenos , Água Doce , Nylons
19.
Water Res ; 254: 121395, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38452527

RESUMO

Forward osmosis (FO) membrane processes could operate without hydraulic pressures, enabling the efficient treatment of wastewaters with mitigated membrane fouling and enhanced efficiency. Designing a high-performance polyamide (PA) layer on ceramic substrates remains a challenge for FO desalination applications. Herein, we report the enhanced water treatment performance of thin-film nanocomposite ceramic-based FO membranes via an in situ grown Zr-MOF (UiO-66-NH2) interlayer. With the Zr-MOF interlayer, the ceramic-based FO membranes exhibit lower thickness, higher cross-linking degree, and increased surface roughness, leading to higher water flux of 27.38 L m-2 h-1 and lower reverse salt flux of 3.45 g m-2 h-1. The ceramic-based FO membranes with Zr-MOF interlayer not only have an application potential in harsh environments such as acidic solution (pH 3) and alkaline solution (pH 11), but also exhibit promising water and reverse salt transport properties, which are better than most MOF-incorporated PA membranes. Furthermore, the membranes could reject major species (ions, oil and organics) with rejections >94 % and water flux of 22.62-14.35 L m-2 h-1 in the treatment of actual alkaline industrial wastewater (pH 8.6). This rational design proposed in this study is not only applicable for the development of a high-quality ceramic-based FO membrane with enhanced performance but also can be potentially extended to more challenging water treatment applications.


Assuntos
Membranas Artificiais , Purificação da Água , Osmose , Águas Residuárias , Cloreto de Sódio , Cerâmica , Nylons
20.
Nat Commun ; 15(1): 1217, 2024 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-38336849

RESUMO

Successes in biocatalytic polyester recycling have raised the possibility of deconstructing alternative polymers enzymatically, with polyamide (PA) being a logical target due to the array of amide-cleaving enzymes present in nature. Here, we screen 40 potential natural and engineered nylon-hydrolyzing enzymes (nylonases), using mass spectrometry to quantify eight compounds resulting from enzymatic nylon-6 (PA6) hydrolysis. Comparative time-course reactions incubated at 40-70 °C showcase enzyme-dependent variations in product distributions and extent of PA6 film depolymerization, with significant nylon deconstruction activity appearing rare. The most active nylonase, a NylCK variant we rationally thermostabilized (an N-terminal nucleophile (Ntn) hydrolase, NylCK-TS, Tm = 87.4 °C, 16.4 °C higher than the wild-type), hydrolyzes 0.67 wt% of a PA6 film. Reactions fail to restart after fresh enzyme addition, indicating that substrate-based limitations, such as restricted enzyme access to hydrolysable bonds, prohibit more extensive deconstruction. Overall, this study expands our understanding of nylonase activity distribution, indicates that Ntn hydrolases may have the greatest potential for further development, and identifies key targets for progressing PA6 enzymatic depolymerization, including improving enzyme activity, product selectivity, and enhancing polymer accessibility.


Assuntos
Caprolactama/análogos & derivados , Nylons , Polímeros , Hidrólise , Polímeros/química , Poliésteres
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