Site-occupancy factors in the Debye scattering equation. A theoretical discussion on significance and correctness.

The Debye scattering equation (DSE) [Debye (1915). Ann. Phys.

Variance analysis of dynamic light scattering data.

We propose a novel method alternative to the classical Dynamic Light Scattering (DLS) technique for performing particle sizing on diluted dispersions of nanosized particles. Differently from DLS, which works by determining the correlation function of the intensity scattered by the sample, our method does not require the use of a correlator because it exploits the behavior of the variance (VAR) of the scattered signal as a function of the sampling time Δt. By using a wide range of sampling times Δtmin ≪ τc ≪ Δtmax, it is possible to recover the correlation time τc of the scattered field and, in turn (by using the Stokes-Einstein relation), the hydrodynamic diameter of the particles.

Light Scattering and Turbidimetry Techniques for the Characterization of Nanoparticles and Nanostructured Networks.

Light scattering and turbidimetry techniques are classical tools for characterizing the dynamics and structure of single nanoparticles or nanostructured networks. They work by analyzing, as a function of time (Dynamic Light Scattering, DLS) or angles (Static Light Scattering, SLS), the light scattered by a sample, or measuring, as a function of the wavelength, the intensity scattered over the entire solid angle when the sample is illuminated with white light (Multi Wavelength Turbidimetry, MWT). Light scattering methods probe different length scales, in the ranges of ~5−500 nm (DLS), or ~0.

Recipes for diffuse correlation spectroscopy instrument design using commonly utilized hardware based on targets for signal-to-noise ratio and precision.

Over the recent years, a typical implementation of diffuse correlation spectroscopy (DCS) instrumentation has been adapted widely. However, there are no detailed and accepted recipes for designing such instrumentation to meet pre-defined signal-to-noise ratio (SNR) and precision targets. These require specific attention due to the subtleties of the DCS signals.

Exploring the Relationship between Disease Awareness and Outcomes in Patients with Chronic Obstructive Pulmonary Disease.

Background: Disease awareness is a challenge in the management of chronic obstructive pulmonary disease (COPD).

Objectives: The aim of this analysis was to explore the association between COPD optimal and suboptimal awareness, clinical parameters, and the following patient-reported outcomes: modified Medical Research Council (mMRC), Treatment Satisfaction Questionnaire (TSQM-9), COPD Assessment Test (CAT), Morisky Medication-Taking Adherence Scale (MMAS-4), and Brief Illness Perception Questionnaire (B-IPQ).

Methods: This post hoc analysis of the SAT study included all enrolled patients for whom awareness (Disease Awareness in COPD Questionnaire - DACQ) was assessed at baseline and 12 months.

Nanoparticle size distribution from inversion of wide angle X-ray total scattering data.

An increasingly important issue in nanoscience and nanotechnology is the accurate determination of nanoparticle sizing. Wide angle X-ray total scattering (WAXTS) data are frequently used to retrieve the Particle Size Distributions (PSDs) of nanocrystals of highly technological relevance; however, the PSD shape typically relies on an a-priori assumption. Here, we propose a modified version of the classical iterative Lucy-Richardson (LR) algorithm, which is simple, fast and highly reliable against noise, and demonstrate that the inversion of WAXTS data can be profitably used for recovering accurate PSD regardless of its shape.

On the amorphous layer in bone mineral and biomimetic apatite: A combined small- and wide-angle X-ray scattering analysis.

The occurrence of an amorphous calcium phosphate layer covering the crystalline apatite core has been suggested to be an intrinsic feature of both bone mineral and synthetic biomimetic analogs. However, an exahustive quantitative picture of the amorphous-crystalline relationship in these materials is still missing. Here, we present a multiple scale modelling that combines small-angle X-ray scattering (SAXS) and synchrotron wide-angle X-ray total scattering (WAXTS) analyses to investigate the amorphous-crystalline spatial interplay in bone sample and biomimetic carbonated nano-apatites.

Structure, Morphology, and Faceting of TiO Photocatalysts by the Debye Scattering Equation Method. The P25 and P90 Cases of Study.

Characterization of functional nanocrystalline materials in terms of quantitative determination of size, size dispersion, type, and extension of exposed facets still remains a challenging task. This is particularly the case of anisotropically shaped nanocrystals (NCs) like the TiO photocatalysts. Here, commercially available P25 and P90 titania nanopowders have been characterized by wide-angle X-ray total scattering techniques.

Gender differences in asthma perception and its impact on quality of life: a post hoc analysis of the PROXIMA (Patient Reported Outcomes and Xolair In the Management of Asthma) study.

Background: Gender differences in asthma perception and control have been reported. The PROXIMA observational study assessed these outcomes in a cohort of Italian severe allergic asthma (SAA) patients. This post hoc analysis of the PROXIMA results was aimed at assessing gender differences in SAA in a real-world setting, focusing on disease perception and impact on quality of life (QoL).

Disease awareness in patients with COPD: measurement and extent.

Background: Patient awareness of COPD refers to knowledge and acceptance of the disease and its treatment. Although it is relevant to management and outcomes, the disease awareness of patients is poorly investigated, and no validated questionnaires are currently available. We aimed to develop the novel Disease Awareness in COPD Questionnaire (DACQ), which was validated in relation to demographic and clinical features, in patients participating in the SATisfaction and Adherence to COPD Treatment (SAT) study.

Statistical analysis of dynamic light scattering data: revisiting and beyond the Schätzel formulas.

We revisited the classical Schätzel formulas (K. Schätzel, Quantum Optics2, 2871990) of the variance and covariance matrix associated to the normalized auto-correlation function in a Dynamic Light Scattering experiment when the sample is characterized by a single exponential decay function. Although thoroughly discussed by Schätzel who also outlined a correcting procedure, such formulas do not include explicitly the effects of triangular averaging that arise when the sampling time Δt is comparable or larger than the correlation time τc.

Ionic conductivity and mixed-ion effect in mixed alkali metaphosphate glasses.

In this work, mixed alkali metaphosphate glasses based on K-Na, Rb-Na, Rb-Li, Cs-Na and Cs-Li combinations were studied by differential scanning calorimetry (DSC), complex impedance spectroscopy, and Raman spectroscopy. DSC analyses show that both the glass transition (T) and melting temperatures (T) exhibit a clear mixed-ion effect. The ionic conductivity shows a strong mixed-ion effect and decreases by more than six orders of magnitude at room temperature for Rb-Na or Cs-Li alkali pairs.

Commercial counterboard for 10 ns software correlator for photon and fluorescence correlation spectroscopy.

A 10 ns time resolution, multi-tau software correlator, capable of computing simultaneous autocorrelation (A-A, B-B) and cross (A-B) correlation functions at count rates up to ∼10 MHz, with no data loss, has been developed in LabVIEW and C++ by using the National Instrument timer/counterboard (NI PCIe-6612) and a fast Personal Computer (PC) (Intel Core i7-4790 Processor 3.60 GHz ). The correlator works by using two algorithms: for large lag times (τ ≳ 1 μs), a classical time-mode scheme, based on the measure of the number of pulses per time interval, is used; differently, for τ ≲ 1 μs a photon-mode (PM) scheme is adopted and the correlation function is retrieved from the sequence of the photon arrival times.

Geena 2, improved automated analysis of MALDI/TOF mass spectra.

Background: Mass spectrometry (MS) is producing high volumes of data supporting oncological sciences, especially for translational research. Most of related elaborations can be carried out by combining existing tools at different levels, but little is currently available for the automation of the fundamental steps. For the analysis of MALDI/TOF spectra, a number of pre-processing steps are required, including joining of isotopic abundances for a given molecular species, normalization of signals against an internal standard, background noise removal, averaging multiple spectra from the same sample, and aligning spectra from different samples.

Hardware simulator for optical correlation spectroscopy with Gaussian statistics and arbitrary correlation functions.

We present a new hardware simulator (HS) for characterization, testing and benchmarking of digital correlators used in various optical correlation spectroscopy experiments where the photon statistics is Gaussian and the corresponding time correlation function can have any arbitrary shape. Starting from the HS developed in [Rev. Sci.

A comprehensive mechanism of fibrin network formation involving early branching and delayed single- to double-strand transition from coupled time-resolved X-ray/light-scattering detection.

The formation of a fibrin network following fibrinogen enzymatic activation is the central event in blood coagulation and has important biomedical and biotechnological implications. A non-covalent polymerization reaction between macromolecular monomers, it consists basically of two complementary processes: elongation/branching generates an interconnected 3D scaffold of relatively thin fibrils, and cooperative lateral aggregation thickens them more than 10-fold. We have studied the early stages up to the gel point by fast fibrinogen:enzyme mixing experiments using simultaneous small-angle X-ray scattering and wide-angle, multi-angle light scattering detection.

Complement C3f serum levels may predict breast cancer risk in women with gross cystic disease of the breast.

Unlabelled: Gross cystic disease (GCDB) is a breast benign condition predisposing to breast cancer. Cryopreserved sera from GCDB patients, some of whom later developed a cancer (cases), were studied to identify potential risk markers. A MALDI-TOF mass spectrometry analysis found several complement C3f fragments having a significant increased abundance in cases compared to controls.

Fast two-dimensional bubble analysis of biopolymer filamentous networks pore size from confocal microscopy thin data stacks.

The average pore size ξ0 of filamentous networks assembled from biological macromolecules is one of the most important physical parameters affecting their biological functions. Modern optical methods, such as confocal microscopy, can noninvasively image such networks, but extracting a quantitative estimate of ξ0 is a nontrivial task. We present here a fast and simple method based on a two-dimensional bubble approach, which works by analyzing one by one the (thresholded) images of a series of three-dimensional thin data stacks.

Modeling of fibrin gels based on confocal microscopy and light-scattering data.

Fibrin gels are biological networks that play a fundamental role in blood coagulation and other patho/physiological processes, such as thrombosis and cancer. Electron and confocal microscopies show a collection of fibers that are relatively monodisperse in diameter, not uniformly distributed, and connected at nodal points with a branching order of ∼3-4. Although in the confocal images the hydrated fibers appear to be quite straight (mass fractal dimension D(m) = 1), for the overall system 1 View Article and Find Full Text PDF

Colors of transparent submicron suspensions on approaching the Rayleigh regime.

The features of scattered and transmitted light by dilute suspensions of transparent submicron particles are investigated both in the spectral and in the perceived colorimetric domains, as a function of effective particle diameter D, particle-host refractive-index mismatch m, and scattering angle θ. Our results show that the wavelength λ-dependence of the scattering and extinction cross sections remains quite similar well beyond the Rayleigh regime up to particle sizes of a few hundreds nm, but only for specific scattering angles that depend on D and m, and tend to 90° on approaching the Rayleigh regime. Close to this limit (D/λ<<1), a simple criterion that relates the perceived scattering color at θ=90° and the ratio of the sample extinction coefficients at two properly selected wavelengths is demonstrated.

Influence of film thickness on the optical transmission through subwavelength single slits in metallic thin films.

Silver and gold films with thicknesses in the range of 120-450 nm were evaporated onto glass substrates. A sequence of slits with widths varying between 70 and 270 nm was milled in the films using a focused gallium ion beam. We have undertaken high-resolution measurements of the optical transmission through the single slits with 488.

Far-field R wave oversensing in dual chamber pacemakers designed for atrial arrhythmia management: effect of pacing site and lead tip to ring distance.

INAMA, G., et al.: Far-Field R Wave Oversensing in Dual Chamber Pacemakers Designed for Atrial Arrhythmia Management: Effect of Pacing Site and Lead Tip to Ring Distance.