Search results for "surface"

Bright blue emission of synthesized silica nanoparticles conferred by surface defects

2013

Temperature-responsive hybrid nanomaterials based on modified halloysite nanotubes uploaded with silver nanoparticles

2022

New temperature-responsive hybrid nanomaterials based on modified halloysite nanotubes (HNTs) containing grafted polymer brushes with silver nanoparticles have been successfully fabricated. We used a three steps process including synthesis of the initiating coatings onto HNTs surface, fabrication of the POEGMA – poly(oligo(ethylene glycol)ethyl ether methacrylate) grafted brushes and synthesis of the silver nanoparticles (AgNPs). The synthesis and properties of hybrid nanomaterials were studied by FT-IR, TGA and DLS methods. It is shown that the introduction of AgNPs, formed from 0.005 M AgNO3 solution leads to a significant reduction of low critical solution temperature (LCST) of the polym…

Localized surface plasmon resonance in silver nanoparticles: Atomistic first-principles time-dependent density-functional theory calculations

2015

We observe using ab initio methods that localized surface plasmon resonances in icosahedral silver nanoparticles enter the asymptotic region already between diameters of 1 and 2 nm, converging close to the classical quasistatic limit around 3.4 eV. We base the observation on time-dependent density-functional theory simulations of the icosahedral silver clusters Ag$_{55}$ (1.06 nm), Ag$_{147}$ (1.60 nm), Ag$_{309}$ (2.14 nm), and Ag$_{561}$ (2.68 nm). The simulation method combines the adiabatic GLLB-SC exchange-correlation functional with real time propagation in an atomic orbital basis set using the projector-augmented wave method. The method has been implemented for the electron structure…

Pulicaria glutinosa Extract: A Toolbox to Synthesize Highly Reduced Graphene Oxide-Silver Nanocomposites

2015

A green, one-step approach for the preparation of graphene/Ag nanocomposites (PE-HRG-Ag) via simultaneous reduction of both graphene oxide (GRO) and silver ions using Pulicaria glutinosa plant extract (PE) as reducing agent is reported. The plant extract functionalizes the surfaces of highly reduced graphene oxide (HRG) which helps in conjugating the Ag NPs to HRG. Increasing amounts of Ag precursor enhanced the density of Ag nanoparticles (NPs) on HRG. The preparation of PE-HRG-Ag nanocomposite is monitored by using ultraviolet-visible (UV-Vis) spectroscopy, powder X-ray diffraction (XRD), and energy dispersive X-ray (EDX). The as-prepared PE-HRG-Ag nanocomposities display excellent surfac…

Maturation of Epidermal Langerhans Cells In Vitro Is Accompanied by Downregulation of 4F2 (CD98) as Determined by Differential Display

1998

Following short-term culture, Langerhans cells mature morphologically and functionally into potent immunostimulatory cells. As regulation of gene expression accompanies this maturation process, it is likely that differentially expressed genes are involved in the maturation events. Using the recently described method of differential display, we generated cDNA expression patterns starting with mRNA of murine epidermal Langerhans cells isolated either directly (fLC) or following 3 d cultivation (cLC). Five hundred putative differentially expressed cDNA fragments were recovered from the gel. For a part of the fragments differential expression was confirmed by dot blot and Southern hybridization…

A fluorescence study of the loading and time stability of doxorubicin in sodium cholate/PEO-PPO-PEO triblock copolymer mixed micelles

2019

Abstract Hypothesis Doxorubicin hydrochloride (DX) is one of the most powerful anticancer agents though its clinical use is impaired by severe undesired side effects. DX encapsulation in nanocarrier systems has been introduced as a mean to reduce its toxicity. Micelles of the nonionic triblock copolymers of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) (PEO-PPO-PEO), are very promising carrier systems. The positive charge of DX confines the drug to the hydrophilic corona region of the micelles. The use of mixed micelles of PEO-PPO-PEO copolymers and a negatively charged bile salt should favour the solubilization of DX in the apolar core region of the micelles. Experiments We st…

Effective Practices in Mitigating Soil Erosion from Fields

2017

Soil erosion by water is a natural process that cannot be avoided. Soil erosion depends on many factors, and a distinction should be made between humanly unchangeable (e.g., rainfall) and modifiable (e.g., length of the field) soil erosion factors. Soil erosion has both on-site and off-site effects. Soil conservation tries to combine modifiable factors so as to maintain erosion in an area of interest to an acceptable level. Strategies to control soil erosion have to be adapted to the desired land use. Knowledge of soil loss tolerance, T, i.e., the maximum admissible erosion from a given field, allows technicians or farmers to establish whether soil conservation practices need to be applied …

Evaluation of Soil Organic Carbon Storage of Atillo in the Ecuadorian Andean Wetlands

2022

Identifying the SOC levels and revealing the potential of SOC storage of ecosystems difficult to sample and study are necessary contributions to the understanding of the global reserves of SOC. Wetlands store large amounts of SOC within their soils. They have an important role in water regulation and have great biological and floristic diversity. Therefore, this study aimed to assess the SOC stock in Atillo micro-watershed in the Ecuadorian Andean wetlands at two soil depths (0–30 cm and 30–60 cm below ground) and to assess the importance of the ecosystem and its conservation in favor of reducing emissions due to degradation processes. For that, we sampled the study zone with 10…

The Influence of Industrial Waste on the Magnetic Properties of Salt-Affected Soils from Two Soda Ash Manufacturing Sites

2021

The aim of this study was to characterize the impact of soda ash manufacturing on the magnetic properties of soils located in the agricultural landscape in north-central Poland. Two study sites were chosen: Mątwy (SM) and Janikowo (SJ). Highly saline soils with halophyte communities were selected in order to develop an understanding of the relationship between salinization of water–soil interface and the potential contamination risk of the environment. Basic chemical and physicochemical properties of topsoil (0–25 cm) and water (surface and groundwater) samples from five locations were characterized. The characteristics of soil contamination were based on the content of sel…

A simple field method to measure the hydrodynamic properties of soil surface crust

2013

The hydraulic resistance of the surface crust was determined by a combination of two infiltrometric techniques: first, a surface measurement of steady-state infiltration rate is conducted by a mini-disk tension infiltrometer (MDI); then, the surface crust is removed, its thickness is measured, and a ponded infiltration test is performed at the same site. The Beerkan Estimation of Soil Transfer parameters (BEST) method is applied to estimate the hydraulic properties of the underlying soil provided the particlesize distribution and the bulk density are known. Under the assumption of a unit gradient of hydraulic head below the soil crust, the pressure head at the interface crust-soil is derive…