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1.
Ecotoxicol Environ Saf ; 286: 117194, 2024 Oct 24.
Artículo en Inglés | MEDLINE | ID: mdl-39454359

RESUMEN

Nanoscale zero valent iron (nZVI) is used to remediate aquifers polluted by organochlorines or heavy metals and was also suggested to eliminate harmful algal blooms. nZVI can therefore affect microorganisms in the vicinity of the application area, including microalgae. However, studies on early transcriptomic effects of microalgae after exposure to nZVI are rare. Here, we described the early physiological and transcriptomic response of the freshwater ecological indicator green microalga, Raphidocelis subcapitata ATCC 22662, to 100 mg/L of reactive nZVI and non-reactive nano-magnetite (nFe3O4). The combined effect of shading and the release of total iron from nZVI posed a short-term inhibition effect leading to 15 % of deformed cells and cytosol leakage, while cells viability increased after 24 h. nZVI triggered a more pronounced transcriptomic response with (7380 differentially expressed genes [DEGs]) compared to nFe3O4 (4601 DEGs) after 1 h. nZVI, but not nFe3O4 increased the expression of genes function in DNA repair and replication, while deactivated carbohydrate-energy metabolisms, mitochondria signaling, and transmembrane ion transport. This study highlights an early fate assessment of algal cells under nZVI and nFe3O4 exposure using next-generation risk assessment methods and will serve as valuable information for safe and sustainable application of nZVI in water remediation.

2.
Int J Mol Sci ; 24(4)2023 Feb 18.
Artículo en Inglés | MEDLINE | ID: mdl-36835521

RESUMEN

Nanotechnology has great potential to significantly advance the biomedical field for the benefit of human health. However, the limited understanding of nano-bio interactions leading to unknowns about the potential adverse health effects of engineered nanomaterials and to the poor efficacy of nanomedicines has hindered their use and commercialization. This is well evidenced considering gold nanoparticles, one of the most promising nanomaterials for biomedical applications. Thus, a fundamental understanding of nano-bio interactions is of interest to nanotoxicology and nanomedicine, enabling the development of safe-by-design nanomaterials and improving the efficacy of nanomedicines. In this review, we introduce the advanced approaches currently applied in nano-bio interaction studies-omics and systems toxicology-to provide insights into the biological effects of nanomaterials at the molecular level. We highlight the use of omics and systems toxicology studies focusing on the assessment of the mechanisms underlying the in vitro biological responses to gold nanoparticles. First, the great potential of gold-based nanoplatforms to improve healthcare along with the main challenges for their clinical translation are presented. We then discuss the current limitations in the translation of omics data to support risk assessment of engineered nanomaterials.


Asunto(s)
Nanopartículas del Metal , Nanopartículas , Nanoestructuras , Humanos , Oro , Nanotecnología , Nanomedicina
3.
Molecules ; 28(22)2023 Nov 16.
Artículo en Inglés | MEDLINE | ID: mdl-38005345

RESUMEN

Thickener, also known as a gelling agent, is a critical component of lubricating greases. The most critical property of thickener, temperature resistance, is determined by the molecular structure of the compounds. Currently, all high-temperature-resistant thickeners are based on 12-hydroxystearic acid, which is exclusively produced from castor oil. Since castor oil is also an important reagent for other processes, finding a sustainable alternative to 12-hydroxystearic acid has significant economic implications. This study synthesises an alternative thickener from abundant agricultural waste, cashew nut shell liquor (CNSL). The synthesis and separation procedure contains three steps: (i) forming and separating calcium anacardate by precipitation, (ii) forming and separating anacardic acid (iii) forming lithium anacardate. The obtained lithium anacardate can be used as a thickener for lubricating grease. It was found that the recovery of anacardic acid was around 80%. The optimal reaction temperature and time conditions for lithium anacardate were 100 °C and 1 h, respectively. The method provides an economical alternative to castor and other vegetable oils. The procedure presents a simple pathway to produce the precursor for the lubricating grease from agricultural waste. The first reaction step can be combined with the existing distillation of cashew nut shell processing. An effective application can promote CNSL to a sustainable feedstock for green chemistry. The process can also be combined with recycled lithium from the spent batteries to improve the sustainability of the battery industry.

4.
Phys Rev Lett ; 128(14): 140601, 2022 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-35476480

RESUMEN

Out-of-time-ordered correlators (OTOCs) are a key observable in a wide range of interconnected fields including many-body physics, quantum information science, and quantum gravity. Measuring OTOCs using near-term quantum simulators will extend our ability to explore fundamental aspects of these fields and the subtle connections between them. Here, we demonstrate an experimental method to measure OTOCs at finite temperatures and use the method to study their temperature dependence. These measurements are performed on a digital quantum computer running a simulation of the transverse field Ising model. Our flexible method, based on the creation of a thermofield double state, can be extended to other models and enables us to probe the OTOC's temperature-dependent decay rate. Measuring this decay rate opens up the possibility of testing the fundamental temperature-dependent bounds on quantum information scrambling.

5.
Phys Rev Lett ; 126(22): 220503, 2021 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-34152167

RESUMEN

In order to scale up quantum processors and achieve a quantum advantage, it is crucial to economize on the power requirement of two-qubit gates, make them robust to drift in experimental parameters, and shorten the gate times. Applicable to all quantum computer architectures whose two-qubit gates rely on phase-space closure, we present here a new gate-optimizing principle according to which negligible amounts of gate fidelity are traded for substantial savings in power, which, in turn, can be traded for substantial increases in gate speed and/or qubit connectivity. As a concrete example, we illustrate the method by constructing optimal pulses for entangling gates on a pair of ions within a trapped-ion chain, one of the leading quantum computing architectures. Our method is direct, noniterative, and linear, and, in some parameter regimes, constructs gate-steering pulses requiring up to an order of magnitude less power than the standard method. Additionally, our method provides increased robustness to mode drift. We verify the new trade-off principle experimentally on our trapped-ion quantum computer.

6.
Curr Microbiol ; 78(3): 979-991, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33521895

RESUMEN

The application of zero-valent iron particles (ZVI) for the treatment of heavily polluted environment and its biological effects have been studied for at least two decades. Still, information on the impact on bacterial metabolic pathways is lacking. This study describes the effect of microscale and nanoscale ZVI (mZVI and nZVI) on the abundance of different metabolic pathways in freshwater bacterial communities. The metabolic pathways were inferred from metabolism modelling based on 16S rRNA gene sequence data using paprica pipeline. The nZVI changed the abundance of numerous metabolic pathways compared to a less influencing mZVI. We identified the 50 most affected pathways, where 31 were related to degradation, 17 to biosynthesis, and 2 to detoxification. The linkage between pathways was two times higher in nZVI samples compared to mZVI, and was specifically higher considering the arsenate detoxification II pathway. Limnohabitans and Roseiflexus were linked to the same pathways in both nZVI and mZVI. The prediction of metabolic pathways increases our knowledge of the impacts of nZVI and mZVI on freshwater bacterioplankton.


Asunto(s)
Chloroflexi , Contaminantes Químicos del Agua , Agua Dulce , Genes de ARNr , Hierro , ARN Ribosómico 16S/genética
7.
Ecotoxicol Environ Saf ; 154: 36-44, 2018 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-29454269

RESUMEN

As nanoremediation strategies for in-situ groundwater treatment extend beyond nanoiron-based applications to adsorption and oxidation, ecotoxicological evaluations of newly developed materials are required. The biological effects of four new materials with different iron (Fe) speciations ([i] FerMEG12 - pristine flake-like milled Fe(0) nanoparticles (nZVI), [ii] Carbo-Iron® - Fe(0)-nanoclusters containing activated carbon (AC) composite, [iii] Trap-Ox® Fe-BEA35 (Fe-zeolite) - Fe-doped zeolite, and [iv] Nano-Goethite - 'pure' FeOOH) were studied using the unicellular green alga Chlamydomonas sp. as a model test system. Algal growth rate, chlorophyll fluorescence, efficiency of photosystem II, membrane integrity and reactive oxygen species (ROS) generation were assessed following exposure to 10, 50 and 500 mg L-1 of the particles for 2 h and 24 h. The particles had a concentration-, material- and time-dependent effect on Chlamydomonas sp., with increased algal growth rate after 24 h. Conversely, significant intracellular ROS levels were detected after 2 h, with much lower levels after 24 h. All Fe-nanomaterials displayed similar Z-average sizes and zeta-potentials at 2 h and 24 h. Effects on Chlamydomonas sp. decreased in the order FerMEG12 > Carbo-Iron® > Fe-zeolite > Nano-Goethite. Ecotoxicological studies were challenged due to some particle properties, i.e. dark colour, effect of constituents and a tendency to agglomerate, especially at high concentrations. All particles exhibited potential to induce significant toxicity at high concentrations (500 mg L-1), though such concentrations would rapidly decrease to mg or µg L-1 in aquatic environments, levels harmless to Chlamydomonas sp. The presented findings contribute to the practical usage of particle-based nanoremediation in environmental restoration.


Asunto(s)
Chlamydomonas/efectos de los fármacos , Restauración y Remediación Ambiental/métodos , Hierro/farmacología , Nanoestructuras/química , Adsorción , Membrana Celular/efectos de los fármacos , Carbón Orgánico/química , Chlamydomonas/crecimiento & desarrollo , Chlamydomonas/metabolismo , Agua Subterránea , Hierro/química , Compuestos de Hierro/química , Minerales/química , Oxidación-Reducción , Especies Reactivas de Oxígeno/metabolismo , Zeolitas/química
8.
NanoImpact ; 35: 100514, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38821169

RESUMEN

Nanoplastics are anticipated to be ubiquitous in various environmental compartments. However, challenges in analytical methods hinder our understanding of risks related to specific nanplastics characteristics such as size and chemical compositions, and interactions between nanoplastics and microorganisms. In this study, we applied fit-for-purpose analytical methods and techniques to understand how nanoplastic chemical composition influences their interaction with bacteria collected from activated sludge. When exposed to polystyrene (PS) and polyvinyl chloride (PVC) nanoplastics for 5 days, the nanoplastics attached to the bacteria. Specifically, on day 1, there was a significant predominance of PS nanoplastics over PVC ones of similar size and shape, possibly due to differences in their chemical composition. After 5 days, there is a substantial decrease in nanoplastics attached to bacteria, suggesting bacterial defence mechanisms may reduce particles attachment over time. The overall bacterial community structure demonstrated a high degree of resilience. This resilience highlights the ability of microbial communities to maintain their structure despite nanoplastic stressors, as evidenced by consistent alpha diversity, PCoA, and PERMANOVA results. Understanding these mechanisms is crucial for assessing nanoplastic fate and thus environmental impacts.


Asunto(s)
Bacterias , Poliestirenos , Cloruro de Polivinilo , Aguas del Alcantarillado , Aguas del Alcantarillado/microbiología , Cloruro de Polivinilo/química , Poliestirenos/química , Nanopartículas/química
9.
Bioprocess Biosyst Eng ; 36(1): 45-56, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-22653036

RESUMEN

We have constructed a reaction network model of Bacillus subtilis. The model was analyzed using a pathway analysis tool called elementary mode analysis (EMA). The analysis tool was used to study the network capabilities and the possible effects of altered culturing conditions on the production of a fibrinolytic enzyme, nattokinase (NK) by B. subtilis. Based on all existing metabolic pathways, the maximum theoretical yield for NK synthesis in B. subtilis under different substrates and oxygen availability was predicted and the optimal culturing condition for NK production was identified. To confirm model predictions, experiments were conducted by testing these culture conditions for their influence on NK activity. The optimal culturing conditions were then applied to batch fermentation, resulting in high NK activity. The EMA approach was also applied for engineering B. subtilis metabolism towards the most efficient pathway for NK synthesis by identifying target genes for deletion and overexpression that enable the cell to produce NK at the maximum theoretical yield. The consistency between experiments and model predictions proves the feasibility of EMA being used to rationally design culture conditions and genetic manipulations for the efficient production of desired products.


Asunto(s)
Bacillus subtilis/enzimología , Proteínas Bacterianas/metabolismo , Metaboloma/fisiología , Modelos Biológicos , Oxígeno/metabolismo , Subtilisinas/biosíntesis , Simulación por Computador , Cinética , Tasa de Depuración Metabólica
10.
Sci Total Environ ; 858(Pt 1): 159569, 2023 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-36272481

RESUMEN

Bio-based plastics (BP) produced from renewable biomass resources, such as high-density polyethylene (HDPE), polylactic acid (PLA) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), is currently increasing in terms of both products and applications. However, their biodegradability and environmental fate are not yet fully understood, especially in freshwaters. Here, we present the results of an in-situ study in a freshwater reservoir, where we submerged HDPE, PLA and PHBV microscale BP (mBP) in dialysis bags to enable exchange of small organic and inorganic molecules, including nutrients, with the surrounding water. After one and two months, the bacterial biofilm that formed on each mBP was characterised by 16S rRNA amplicon sequencing. After two-months, Oxalobacteraceae, Pedosphaeraceae, Flavobacteriaceae (Flavobacterium) and Chitinophagaceae (Ferruginibacter) had increased by up to four times. Both these and other common members (≥1 % relative total biomass) of the microbial community were similarly abundant on all mBP. Low-abundance (0.3-1 %) bacterial taxa, however, were significantly more diverse and differed on each mBP. Notably, some low-abundance families and genera increased on specific materials, e.g. Sphingomonadaceae on HDPE, Sphingobacteriaceae on PHBV, Gemmatimonas and Crenothrix on PLA. Overall, abundant bacteria were regarded as a pioneering community, while low-abundance bacteria were more diverse and preferred mBP types in the early stages of biofilm formation on mBP. It could be influenced by the environmental conditions, where nutrient levels and low temperatures might shape the low-abundance of attached bacterial communities than the plastic material itself.


Asunto(s)
Microplásticos , Plásticos , Humanos , ARN Ribosómico 16S/genética , Polietileno , Diálisis Renal , Agua Dulce , Biopelículas , Bacterias , Poliésteres
11.
In Vivo ; 37(4): 1743-1750, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37369463

RESUMEN

BACKGROUND/AIM: A prospective randomized, open-label, single-blinded clinical trial was conducted to evaluate the efficacy of AFree on the symptoms and course of moderate and severe COVID-19 in the field hospital. PATIENTS AND METHODS: Two hundred hospitalized patients diagnosed with COVID-19 were enrolled. The patients were randomized into 100 patients in the interventional AFree group and 100 in the control group. The AFree group patients were treated with AFree oral spray in conjunction with the standard COVID-19 treatment protocol, while the control group of patients were treated with only standard care. RESULTS: Patients of the AFree group demonstrated a remarkedly faster improvement in all COVID-19-related symptoms, resulting in a shorter time for complete recovery than the control group. More importantly, they showed a shorter time for complete viral clearance. Adding AFree to the standard of care protocol also significantly improved the restoration of taste and smell and reduced lung infiltration. Additionally, the patients in the AFree group also exhibited fewer adverse effects related to treatment. CONCLUSION: AFree oral spray is a simple-to-use, safe, and effective adjunctive treatment for moderate and severe COVID-19 cases. AFree oral spray was demonstrated to potentially be effective for COVID-19 prevention.


Asunto(s)
COVID-19 , Humanos , Vaporizadores Orales , SARS-CoV-2 , Tratamiento Farmacológico de COVID-19 , Estudios Prospectivos , Unidades Móviles de Salud , Resultado del Tratamiento
12.
Appl Microbiol Biotechnol ; 94(5): 1387-98, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22526806

RESUMEN

Elementary mode analysis (EMA) identifies all possible metabolic states of the cell metabolic network. Investigation of these states can provide a detailed insight into the underlying metabolism in the cell. In this study, the flux states of Scheffersomyces (Pichia) stipitis metabolism were examined. It was shown that increasing oxygen levels led to a decrease of ethanol synthesis. This trend was confirmed by experimental evaluation of S. stipitis in glucose-xylose fermentation. The oxygen transfer rate for an optimal ethanol production was 1.8 mmol/l/h, which gave the ethanol yield of 0.40 g/g and the ethanol productivity of 0.25 g/l/h. For a better understanding of the cell's regulatory mechanism in response to oxygenation levels, EMA was used to examine metabolic flux patterns under different oxygen levels. Up- and downregulation of enzymes in the network during the change of culturing condition from oxygen limitation to oxygen sufficiency were identified. The results indicated the flexibility of S. stipitis metabolism to cope with oxygen availability. In addition, relevant genetic targets towards improved ethanol-producing strains under all oxygenation levels were identified. These targeted genes limited the metabolic functionality of the cell to function according to the most efficient ethanol synthesis pathways. The presented approach is promising and can contribute to the development of culture optimization and strain engineers for improved lignocellulosic ethanol production by S. stipitis.


Asunto(s)
Etanol/metabolismo , Redes y Vías Metabólicas/genética , Oxígeno/metabolismo , Saccharomycetales/metabolismo , Regulación Fúngica de la Expresión Génica , Saccharomycetales/genética
13.
Health Psychol Rep ; 10(4): 266-279, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-38084134

RESUMEN

BACKGROUND: Many studies have shown the effects of parental migration on the psychological and daily life of left-behind children (LBC) of labor migrant parents, but the results on school-related problems of LBC remain inconsistent. Additionally, there is a dearth of research on the factors affecting school problems among LBC, especially in the socio-cultural context of Vietnam. The purpose of this study was to confirm the school problems encountered by LBC in comparison with non-left-behind children (non-LBC). The study also aimed to examine variables of bonding of caregivers with children and resilience of children affecting school problems of LBC. PARTICIPANTS AND PROCEDURE: The convenient sampling approach was used in the study. The study sample included 792 Vietnamese school students (Mage = 12.65, SD = 1.60), with 439 children of labor migrant parents and a control group of 353 children of non-migrant parents. The School Problem Questionnaire, Parental Bonding Instrument and the Resilience Scale were employed in this study. RESULTS: There was no difference in school problems between the LBC and non-LBC groups. Resilience by goal planning (RGP), resilience by affect control (RAC), and resilience by family support (RFS) were identified as protective variables for children to overcome difficulties encountered in schools, with regression coefficients of -.21, -.33 and -.20, respectively. Meanwhile, bonding of caregivers with children by control (BCCo), and resilience by positive thinking (RPT) were found to be factors that increase school problems among LBC with the same regression coefficient of .12. CONCLUSIONS: Activities to support LBC should pay attention to improving resilience, namely affect control, goal planning, and promoting the role of caregivers for LBC.

14.
J Hazard Mater ; 439: 129627, 2022 10 05.
Artículo en Inglés | MEDLINE | ID: mdl-35872458

RESUMEN

Nanoscale zero-valent iron (nZVI) has increasingly been applied to remediate aquifers polluted by organochlorines or heavy metals. As a result, bacteria in the vicinity of remediate action can be stressed by surplus iron released from nZVI. However, the understanding of the iron stress defense pathways during this process is currently incomplete. Therefore, we aimed to elucidate the physiological and transcriptomic response of the bacterium, Pseudomonas putida NCTC 10936, to 100 mg/L of nZVI and 44.5 µg/L of dissolved iron obtained from nZVI suspension. Cell viability was neither affected by nZVI nor dissolved iron, although the dissolved iron caused stress that altered the cell physiology and caused the generation of smaller cells, whereas cells were elongated in the presence of nZVI. Transcriptomic analysis confirmed the observed stronger physiological effect caused by dissolved iron (in total 3839 differentially expressed genes [DEGs]) than by nZVI (945 DEGs). Dissolved iron (but not nZVI) activated genes involved in oxidative stress-related pathways, antioxidant activity, carbohydrate and energy metabolism, but downregulated genes associated with flagellar assembly proteins and two-component systems involved in sensing external stimuli. As a result, bacteria very effectively faced oxidative insults and cell viability was not affected.


Asunto(s)
Metales Pesados , Pseudomonas putida , Hierro , Oxidación-Reducción , Estrés Oxidativo , Pseudomonas putida/genética
15.
Sci Total Environ ; 817: 152888, 2022 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-34998775

RESUMEN

Rising concern about emerging and already persisting pollutants in water has urged the scientific community to develop novel remedial techniques. A new group of remediation methods is based on the modification of nanoscale zero-valent iron particles (nZVI), which are well known for treating volatile organic compounds and heavy metals. The properties of nZVI may be further enhanced by modifying their structure or surface using "green" polymers. Herein, nZVI was modified by a ß-cyclodextrin polymer (ß-CDP), which is considered an environmentally safe and inexpensive adsorbent of contaminants. This composite was used for the first time for the degradation of sulfamethoxazole (SMX). Coating by ß-CDP not only enhanced the degradation of SMX (>95%, under 10 min) by the nanoparticles in a wide pH range (3-9) and enabled their efficient reusability (for three cycles) but also made the coated nZVI less toxic to the model bioindicator microalga Raphidocelis subcapitata. Moreover, degradation products of SMX were found to be less toxic to Escherichia coli bacteria and R. subcapitata microalga, contrary to the SMX antibiotic itself, indicating a simple and eco-friendly cleaning process. This research aims to further stimulate and develop novel remedial techniques based on nZVI, and provides a potential application in the degradation of antibiotics in a wide pH range. Moreover, the wealth of available cyclodextrin materials used for surface modification may open a way to discover more efficient and attractive composites for environmental applications.


Asunto(s)
Ciclodextrinas , Metales Pesados , Contaminantes Químicos del Agua , Celulosa , Hierro/química , Sulfametoxazol/toxicidad , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/toxicidad
16.
Polymers (Basel) ; 14(15)2022 Jul 31.
Artículo en Inglés | MEDLINE | ID: mdl-35956636

RESUMEN

The accumulation of organic contaminants including dyes in aquatic systems is of significant environmental concern, necessitating the development of affordable and sustainable materials for the treatment/elimination of these hazardous pollutants. Here, a green synthesis strategy has been used to develop a self-assembled gum kondagogu-sodium alginate bioconjugate sponge adorned with silver nanoparticles, for the first time. The properties of the nanocomposite sponge were then analyzed using FTIR, TGA, SEM, and MicroCT. The ensued biobased sponge exhibited hierarchical microstructure, open cellular pores, good shape memory, and mechanical properties. It merges the attributes of an open cellular porous structure with metal nanoparticles and are envisaged to be deployed as a sustainable catalytic system for reducing contaminants in the aqueous environment. This nanocomposite sponge showed enhanced catalytic effectiveness (km values up to 37 min-1 g-1 and 44 min-1 g-1 for methylene blue and 4-nitrophenol, respectively), antibacterial properties, reusability, and biodegradability (65% biodegradation in 28 days).

17.
Nanoscale ; 14(48): 18143-18156, 2022 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-36449011

RESUMEN

Decades of antibiotic use and misuse have generated selective pressure toward the rise of antibiotic-resistant bacteria, which now contaminate our environment and pose a major threat to humanity. According to the evolutionary "Red queen theory", developing new antimicrobial technologies is both urgent and mandatory. While new antibiotics and antibacterial technologies have been developed, most fail to penetrate the biofilm that protects bacteria against external antimicrobial attacks. Hence, new antimicrobial formulations should combine toxicity for bacteria, biofilm permeation ability, biofilm deterioration capability, and tolerability by the organism without renouncing compatibility with a sustainable, low-cost, and scalable production route as well as an acceptable ecological impact after the ineluctable release of the antibacterial compound in the environment. Here, we report on the use of silver nanoparticles (NPs) doped with magnetic elements (Co and Fe) that allow standard silver antibacterial agents to perforate bacterial biofilms through magnetophoretic migration upon the application of an external magnetic field. The method has been proved to be effective in opening micrometric channels and reducing the thicknesses of models of biofilms containing bacteria such as Enterococcus faecalis, Enterobacter cloacae, and Bacillus subtilis. Besides, the NPs increase the membrane lipid peroxidation biomarkers through the formation of reactive oxygen species in E. faecalis, E. cloacae, B. subtilis, and Pseudomonas putida colonies. The NPs are produced using a one-step, scalable, and environmentally low-cost procedure based on laser ablation in a liquid, allowing easy transfer to real-world applications. The antibacterial effectiveness of these magnetic silver NPs may be further optimized by engineering the external magnetic fields and surface conjugation with specific functionalities for biofilm disruption or bactericidal effectiveness.


Asunto(s)
Antiinfecciosos , Nanopartículas del Metal , Plata/farmacología , Biopelículas , Antibacterianos/farmacología , Enterococcus faecalis , Fenómenos Magnéticos , Pruebas de Sensibilidad Microbiana
18.
Carbohydr Polym ; 266: 118126, 2021 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-34044942

RESUMEN

Tree gums are a class of abundantly available carbohydrate polymers that have not been explored thoroughly in film fabrication for food packaging. Films obtained from pristine tree gums are often brittle, hygroscopic, and lack mechanical strength. This study focuses on the chemical modification of gum kondagogu using long-chain alkenyl groups of dodecenyl succinic anhydride (DDSA), an esterifying agent that introduces a 12-carbon hydrophobic chain to the kondagogu structure. The esterification reaction was confirmed by 1H nuclear magnetic resonance and Fourier-transform infrared spectroscopy. The effect of nano-cellulose as an additive on various film properties was investigated. The developed films were characterized for their mechanical, morphological, optical, barrier, antibacterial, and biodegradable properties. The inclusion of long-chain carbon groups acted as internal plasticizers and resulted in an amorphous structure with better film-forming ability, improved hydrophobicity, and higher elongation at break values. The modified films exhibited antibacterial properties and excellent biodegradability under aerobic conditions.


Asunto(s)
Alquenos/farmacología , Bixaceae/química , Embalaje de Alimentos , Gomas de Plantas/farmacología , Anhídridos Succínicos/química , Alquenos/síntesis química , Alquenos/química , Antibacterianos/síntesis química , Antibacterianos/química , Antibacterianos/farmacología , Plásticos Biodegradables/síntesis química , Plásticos Biodegradables/química , Plásticos Biodegradables/farmacología , Módulo de Elasticidad , Escherichia coli/efectos de los fármacos , Interacciones Hidrofóbicas e Hidrofílicas , Ensayo de Materiales , Gomas de Plantas/síntesis química , Gomas de Plantas/química , Staphylococcus aureus/efectos de los fármacos , Resistencia a la Tracción
19.
Chemosphere ; 281: 130915, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34029963

RESUMEN

Abiotic and biotic remediation of chlorinated ethenes (CEs) in groundwater from a real contaminated site was studied using biochar-based composites containing nanoscale zero-valent iron (nZVI/BC) and natural resident microbes/specific CE degraders supported by a whey addition. The material represented by the biochar matrix decorated by isolated iron nanoparticles or their aggregates, along with the added whey, was capable of a stepwise dechlorination of CEs. The tested materials (nZVI/BC and BC) were able to decrease the original TCE concentration by 99% in 30 days. Nevertheless, regarding the transformation products, it was clear that biotic as well as abiotic transformation mechanisms were involved in the transformation process when nonchlorinated volatiles (i.e., methane, ethane, ethene, and acetylene) were detected after the application of nZVI/BC and nZVI/BC with whey. The whey addition caused a massive increase in bacterial biomass in the groundwater samples (monitored by 16S rRNA sequencing and qPCR) that corresponded with the transformation of trichloro- and dichloro-CEs, and this process was accompanied by the formation of less chlorinated products. Moreover, the biostimulation step also eliminated the adverse effect caused by nZVI/BC (decrease in microbial biomass after nZVI/BC addition). The nZVI/BC material or its aging products, and probably together with vinyl chloride-respiring bacteria, were able to continue the further reductive dechlorination of dichlorinated CEs into nonhalogenated volatiles. Overall, the results of the present study demonstrate the potential, feasibility, and environmental safety of this nanobioremediation approach.


Asunto(s)
Agua Subterránea , Contaminantes Químicos del Agua , Carbón Orgánico , ARN Ribosómico 16S/genética , Solventes
20.
Nat Commun ; 11(1): 3720, 2020 Jul 24.
Artículo en Inglés | MEDLINE | ID: mdl-32709855

RESUMEN

The quantum walk formalism is a widely used and highly successful framework for modeling quantum systems, such as simulations of the Dirac equation, different dynamics in both the low and high energy regime, and for developing a wide range of quantum algorithms. Here we present the circuit-based implementation of a discrete-time quantum walk in position space on a five-qubit trapped-ion quantum processor. We encode the space of walker positions in particular multi-qubit states and program the system to operate with different quantum walk parameters, experimentally realizing a Dirac cellular automaton with tunable mass parameter. The quantum walk circuits and position state mapping scale favorably to a larger model and physical systems, allowing the implementation of any algorithm based on discrete-time quantum walks algorithm and the dynamics associated with the discretized version of the Dirac equation.

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