3,636 research outputs found
Scanning probe microscopy techniques for mechanical characterization at nanoscale
Three atomic force microscopy (AFM)-based techniques are reviewed that allow one to conduct accurate measurements of mechanical properties of either stiff or compliant materials at a nanometer scale. Atomic force acoustic microscopy, AFM-based depth sensing indentation, and torsional harmonic AFM are briefly described. Examples and results of quantitative characterization of stiff (an ultrathin SeSn film), soft polymeric (polyaniline fibers doped with detonation nanodiamond) and biological (collagen fibers) materials are reported
Microscopies at the nanoscale for nano-scale drug delivery systems
One of the frontier of nanoscience is undoubtedly represented by the use of nanotechnologies
in the pharmaceutical research. During the last decades a big family of nanostructures that have a
surface-acting action, such as NanoParticles (NPs), lipid nanocarriers and many more, have been developed
to be used as Drug Delivery Systems (DDSs). However, these nanocarriers opened also new
frontiers in nanometrology, requiring an accurate morphological characterization, near atomic resolution,
before they are really available to clinicians to ascertain their elemental composition, to exclude the presence of contaminants
introduced during the synthesis procedure and to ensure biocompatibility. Classical Transmission (TEM) and
Scanning Electron Microscopy (SEM) techniques frequently have to be adapted for an accurate analysis of formulation
morphology, especially in case of hydrated colloidal systems. Specific techniques such as environmental scanning microscopy
and/or cryo preparation are required for their investigation. Analytical Electron Microscopy (AEM) techniques such
as Electron Energy-Loss Spectroscopy (EELS) or Energy-Dispersive X-ray Spectroscopy (EDXS) are additional assets to
determine the elemental composition of the systems. Here we will discuss the importance of Electron Microscopy (EM) as
a reliable tool in the pharmaceutical research of the 21st century, focalizing our attention on advantages and limitations of
different kind of NPs (in particular silver and carbon NPs, cubosomes) and vesicles (liposomes and niosomes)
Current nanocarrier strategies improve vitamin B12 pharmacokinetics, ameliorate patients’ lives, and reduce costs
Vitamin B12 (VitB12) is a naturally occurring compound produced by microorganisms and an essential nutrient for humans. Several papers highlight the role of VitB12 deficiency in bone and heart health, depression, memory performance, fertility, embryo development, and cancer, while VitB12 treatment is crucial for survival in inborn errors of VitB12 metabolism. VitB12 is administrated through intramuscular injection, thus impacting the patients’ lifestyle, although it is known that oral administration may meet the specific requirement even in the case of malabsorption. Furthermore, the high-dose injection of VitB12 does not ensure a constant dosage, while the oral route allows only 1.2% of the vitamin to be absorbed in human beings. Nanocarriers are promising nanotechnology that can enable therapies to be improved, reducing side effects. Today, nanocarrier strategies applied at VitB12 delivery are at the initial phase and aim to simplify administration, reduce costs, improve pharmacokinetics, and ameliorate the quality of patients’ lives. The safety of nanotechnologies is still under investigation and few treatments involving nanocarriers have been approved, so far. Here, we highlight the role of VitB12 in human metabolism and diseases, and the issues linked to its molecule properties, and discuss how nanocarriers can improve the therapy and supplementation of the vitamin and reduce possible side effects and limits
Atomic force microscopy techniques for nanomechanical characterization : a polymer case study
Atomic force microscopy (AFM) is a versatile tool to perform mechanical
characterization of surface samples at the nanoscale. In this work, we review
two of such methods, namely contact resonance AFM (CR-AFM) and torsional
harmonics AFM (TH-AFM). First, such techniques are illustrated and their
applicability on materials with elastic moduli in different ranges are discussed,
together with their main advantages and limitations. Then, a case
study is presented in which we report the mechanical characterization using
both CR-AFM and TH-AFM of polyaniline and polyaniniline doped with
nanodiamond particles tablets prepared by a pressing process. We determined
the indentation modulus values of their surfaces, which were found in fairly
good agreement, thus demonstrating the accuracy of the techniques. Finally,
the determined surface elastic moduli have been compared with the bulk ones
measured through standard indentation testing.
INTRODUCTION
In the field of nanotechnology, the development of
innovative and nondestructive characterization
techniques plays a crucial role. Indeed, the characterization
of nanostructured hybrid materials (e.g.,
thin films and nanocomposites) and devices requires
the capability of acquiring maps of the local mechanical
properties at the nanoscale. Nanoindentation
is the most common method for determining the
mechanical properties of thin films. However, its
applicability is strictly limited by the thickness of
the sample. Furthermore, its poor spatial resolution
does not allow the reconstruction of an accurate
distribution of the sample surface mechanical
properties. For this reason, alternative methods,
based on atomic force microscopy (AFM), have been
developed. By exploiting the high resolution of the
AFM, maps of the surface mechanical properties
(i.e., indentation modulus) can be achieved. Among
these techniques, AFM nanoindentation1 is the
simplest method used to evaluate the local mechanical
properties o
Kaon physics with the KLOE detector
In this paper we discuss the recent finalized analyses by the KLOE experiment
at DANE: the CPT and Lorentz invariance test with entangled pairs, and the precision measurement of the branching fraction of
the decay . We also present the
status of an ongoing analysis aiming to precisely measure the mass
Smart magnetic nanovesicles for theranostic application: Preparation and characterization
Nanomedicines are submicrometer-sized carrier materials designed to improve the biodistribution of systemically administered (chemo)therapeutic agents. By delivering pharmacologically active agents more effectively and more
selectively to the pathological site nanomedicines aim to improve the balance between the efficacy and the toxicity of systemic (chemo)therapeutic administrations. Nanomedicine formulations have also been used for imaging applications and, in recent years, for theranostic approaches, that is, for systems and strategies in which
disease diagnosis and therapy are combined. On the one hand, “classical” drug delivery systems are being co-loaded with both drugs and contrast agents. Actually, nanomaterials with an intrinsic ability to be used for imaging purposes, such as iron-oxide–based magnetic nanoparticles (MNPs), are increasingly being loaded with
drugs or alone for combining disease diagnosis and therapy. In this study, non-ionic surfactant vesicles loaded with lipophilic and hydrophilic MNPs have been prepared.
Vesicles have been characterized in terms of dimensions, ζ-potential, time stability, bilayer characteristics and overall iron content. The encouraging obtained results
confirm that Tween 20 and Span 20 vesicles could be promising carriers for the delivery of hydrophilic and lipophilic MNPs, respectively, thereby prompting various
opportunities for the development of suitable theranostic strategies. The analyzed formulations confirm the importance of surfactant chemical-physical characteristics
in entrapping the MNPs of different polarity, highlighting the high versatility of niosomal bilayer and structure; property that make them so appealing among drug delivery nanocarriers
Scientific basis of nanotechnology, implications for the food sector and future trends
Nanotechnologies are opening up new horizons in almost all
scientific and technological fields. Among these, applications
of nanotechnologies are expected to bring large benefits and
add value to the food and food-related industries through the current regulatory framework
whole food chain, from production to processing, safety, packaging,
transportation, storage and delivery. Nanotechnology
consists in the realization and manipulation of nano-sized
matter, the unique properties of which with respect to their
bulk counterparts are illustrated and discussed. Then, the
main tools and techniques routinely used in nanotechnology
for the nanoscale characterization of food matrices as well
as for the analytical determination of nanomaterials in food
samples are reviewed. Finally, safety and risk assessment issues
are discussed and an overview of applications of nanotechnology
to the food sector is provided along with a description of th
Study of MDT calibration constants using H8 testbeam data of year 2004
In year 2004 Atlas performed a long campaign of test beam data taking at the H8 Cern beam. Two sectors of the barrel and endcap regions of the Muon Spectrometer were exposed to the beam and large amount of data were collected in well defined and controlled operating conditions. This allowed a careful study on MDT drift properties. A better understanding of the calibration constants, of their definition and determination and of the criteria for their acceptance has been obtained. Systematic effects and time stability of the constants have also been studied
Ten years of pluviometric analyses in Italy for civil protection purposes
The concept of climate change has grown in recent decades, influencing the scientific community to conduct research on meteorological parameters and their variabilities. Research on global warming, as well as on its possible economic and environmental consequences, has spread over the last 20 years. Diffused changes in trends have been stated by several authors throughout the world, with different developments observed depending on the continent. Following a period of approximately 40 days of almost continuous rain that occurred from October to November 2019 across the Italian territory and caused several hazards (e.g., floods and landslides), a relevant question for decision-makers and civil protection actors emerged regarding the relative frequencies of given rainfall events in the Warning Hazard Zones (WHZs) of Italy. The derived products of this work could answer this question for both weather and hydrogeological operators thanks to the frequency and spatio-temporal distribution analyses conducted on 10-year daily rainfall data over the entire Italian territory. This work aspires to be an additional tool used to analyse events that have occurred, providing further information for a better understanding of the probability of occurrence and distribution of future events
CONFRONTO DEI PARAMETRI GEOTECNICI E GEOFISICI PRE E POST BLAST TEST PRESSO IL SITO SPERIMENTALE DI MIRABELLO (FE)
L'articolo presenta alcuni risultati preliminari derivanti dal primo esperimento di liquefazione indotta tramite blast test realizzato in Italia, presso Mirabello (FE), comune fortemente colpito da fenomeni di liquefazione durante la sequenza sismica verificatasi in Emilia-Romagna nel 2012. In particolare diverse indagini in sito con tecniche invasive e non invasive sono state eseguite prima e dopo le detonazioni per confrontare la variazione dei parametri geotecnici e geofisici nel tempo
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