Targeted color design of silver-gold alloy nanoparticles.

This research article focuses on the targeted color design of silver-gold alloy nanoparticles (NPs), employing a multivariate optimization approach. NP synthesis involves interconnected process parameters, making independent variation challenging. Data-based property-process relationships are established to optimize optical properties effectively. We define a color target, employ a green chemical co-reduction method at room temperature and optimize process parameters accordingly. The CIEL*a*b* color space (Commission Internationale de l'Éclairage - International Commission on Illumination) and Euclidean distances facilitate accurate color matching to establish the property-process relationship. Concurrently, theoretical Mie calculations explore the structure-property relationship across particle sizes, concentrations, and molar gold contents. The theoretically optimal structure agrees very well with experimental particle structures at the property-process relationship's optimum. The data-driven property-process relationship provides valuable insights into the formation mechanism of a complex particle system, sheds light on the role of relevant process parameters and allows to evaluate the practically available property space. Model validation beyond the original grid demonstrates its robustness, yielding colors close to the target. Additionally, Design of Experiments (DoE) methods reduce experimental work by threefold with slight accuracy trade-offs. Our novel methodology for targeted color design demonstrates how data-based methods can be utilized alongside structure-property relationships to unravel property-process relationships in the design of complex nanoparticle systems and paves the way for future developments in targeted property design.

Multidimensional characterization of noble metal alloy nanoparticles by multiwavelength analytical ultracentrifugation.

In this study, we introduce a method for the simultaneous retrieval of two-dimensional size-composition distributions of noble metal Ag-Au alloy nanoparticles utilizing an analytical ultracentrifuge equipped with a multiwavelength extinction detector (MWL-AUC). MWL-AUC is used to measure coupled optical and sedimentation properties of the particles. The optical response of the nanoparticles is calculated using Mie's theory, where the particles' complex refractive index is corrected due to the effect of reduced mean free path of electrons. Using a combined analysis of the hydrodynamic and spectral data captured by MWL-AUC, the size and composition of the alloy particles is retrieved. Our method is validated through the analysis of synthetic data and by the very good agreement between experimental scanning transmission electron microscopy and our AUC data. The presented comprehensive characterization approach contributes to improved synthesis, scale-up and production of particulate systems as it provides a simple, fast and direct method to determine noble metal alloy nanoparticle size and composition distributions simultaneously.

Biopharmaceutics of liposomal interleukin 2, oncolipin.

Oncolipin is a multilamellar liposomal (dimyristoyl phosphatidylcholine) formulation of interleukin 2 (IL-2) and human serum albumin (HSA) with distinct surface characteristics which may influence its biological activities. IL-2 and HSA were detected on the surface of the liposomes using specific antibody staining. Surface expression of IL-2 was also demonstrated by the observation that Oncolipin bound to cells expressing IL-2 receptors (IL-2R) containing alphabetagamma or betagamma subunits. Binding and internalization of Oncolipin by cells expressing alphabetagamma or betagamma receptor subunits was blocked by excess free IL-2 or a neutralizing antibody against the beta chain. The display of surface IL-2 on Oncolipin's liposomes was maintained in vivo after intravenous injection into mice. IL-2 was also present between the lipid bilayers of the multilamellar liposomes based on the unique physical characteristics detected by freeze fracture electron microscopy. The bulk of the liposome-associated IL-2 was released from the liposomes upon incubation at 37 degrees C in medium containing serum, indicating that the IL-2 was not irreversibly entrapped on or in the liposome structure. Thus, Oncolipin is receptor-targeted to activated T and NK cells by virtue of its surface expression of IL-2 and has the potential to release IL-2 following deposition within lymphoid organs. These properties may confer distinct advantages over soluble IL-2 for immunotherapy of cancer and viral diseases.

A comparison of biodistribution of liposomal and soluble IL-2 by a new method based on time-resolved fluorometry of europium.

A novel method was developed to determine the pharmacokinetics and biodistribution of cytokines and lymphokines based on time-resolved fluorometry (TRF) of europium (Eu). The comparison of two formulations of IL-2 was used to illustrate the sensitivity and applicability of this method as well as to extend the information on the pharmacokinetics of liposomal IL-2 and soluble IL-2. The blood kinetics and biodistribution of liposomal and soluble IL-2 in lymphoid organs and kidneys as measured by TRF were similar to those determined by the radioisotopic method. In both instances, the formulation of IL-2 into liposomes increased its serum half-life and accumulation in reticuloendothelial and lymphoid organs. The increased sensitivity of the Eu/TRF method permitted the extension of observational time points and the analysis of biodistribution in organs such as lymph nodes and bone marrow. These results suggest that Eu-labelled proteins in conjunction with TRF offer a suitable alternative to radiolabelled proteins for pharmacokinetics and tissue distribution studies in animals. This method offers distinct advantages over traditional techniques employing radioistopes since it has greater sensitivity, no half-life limitations and no radioactive or hazardous waste disposal.

Old problem, different approach: alternatives to physical restraints.

Individualized care, resident assessment by a multidisciplinary team, and rehabilitation enhance functional independence in nursing home residents. Creativity in choosing alternatives to restraints was important in successful restraint reduction. Residents free of restraints had higher ADL levels, were more continent, and sustained fewer serious injuries, all of which are important quality of life indicators.

Optic- and computer-aided surgery.

Optic- and computer-aided surgery is a new, original tool for the diagnosis of dismorphies, both in its conception (digitalization of a Moiré pattern on the body) and in its applications (predominantly surgical, for legal medicine and didactic purposes). By means of this three-dimensional (3D) method of measurement by digitalized Moiré, the forms of the body in general and those of the face in particular can be studied and quantified with a high degree of accuracy. This precision in the geometrical analysis of its forms is achieved by combining the latest developments in optics and computer technology. This article presents the current state of the authors' research in the 3D synthesis and manipulation of the human image.

[OCAS (Optic and computer aided surgery)]. / OCAS (Optic and computer aided surgery).

OCAS is a new, original tool for the diagnosis of dismorphies, both in its conception (digitalisation of a moiré pattern on the body) and in its applications (predominantly surgical, for legal medicine and didactic purposes). By means of this new 3D method of measurement by digitalised moiré, the forms of the body in general, and those of the face in particular, can be studied and quantified with a high degree of accuracy. This precision in the geometrical analysis of its forms is achieved by combining the very latest developments in optics and computer technology. The authors present the current state of their research in the 3D synthesis and manipulation of the human image.

Real-time holographic phase organization technique to obtain customized contouring of diffuse surfaces.

We report on the development of a holographic technique which allows one to obtain real time holographic fringes that reveal the whole field contour map of an arbitrary shaped object. The method enables one to generate sensitivities compatible with the relief variations of objects of broadly varying depths. This is achieved by supplying enough 3-D modulation capacity to the system to develop the desired sensitivity. The intersection planes can be pivoted to provide for an oblique slicing of the model. We describe the basic optical configuration and discuss the system parameters. Experimental results are presented to illustrate the effectiveness of the method.

Novel concept for obtaining continuously variable topographic contour mapping using holographic interferometry.

A holographic technique is developed which allows one to obtain in real time the contour map of an arbitrarily shaped object. The method provides a relatively coarse contouring of the object. While still operating at low sensitivities, the method suffers from a breakdown in its functioning due to a saturation of the phase carrying capacity of the interferometer. As a consequence, a phase management strategy is introduced, whose incorporation to the technique enables a substantial improvement of its performance. These developments are systematically analyzed and presented. The method is whole field and noncontacting. The live and flexible character of the method enables one to rapidly generate sensitivities tuned to the relief variations of objects of broadly varying depths. Experimental results are presented to illustrate the feasibility of the proposals.

Noninvasive observation of embryonic behavior in chicks using holographic interference.

Laser holographic techniques offer a sensitive means of detecting small displacements. This paper describes the use of holographic interference to study the movements of an embryo in an intact incubating egg. The method is noninvasive and enables one to monitor the development of behavior in the chick embryo. Movements are displayed in the form of fringes on a TV screen and recorded on videocassettes as a function of time. This is the first report of the use of an optical interference phenomenon to detect movements of an embryo. Besides being useful in the study of the prenatal motility cycle, the method allows one to discriminate diverse types of movement, their onset, duration, and frequency of repetition. Examples are provided to illustrate some movements. The spectacular holographic aided visioning of the pipping behavior of the chick embryo is then briefly described.

Mechanical testing of the external fixator by holographic interferometry.

Tests carried out on the Hoffmann- Vidal external fixator by means of holographic interferometry are reported. These tests refer exclusively to the quality of functioning of the joints connecting transfixing pins and side bars. It is a question of 1) evaluating the behavior of the ball joint subjected to realistic loads, 2) verifying the rigidity of a lightened joint bowl as compared to a heavier one, and 3) comparing the respective resistance of two similar joint models to a rotation of the bar around its axis. The main findings are the remarkable elastic behavior of the ball joint, the effectiveness of the lightened bowl, and the fact that two cousin models may behave quite differently with respect to their resistance to axial slipping rotation of the bar. The interferometric technique is thus expected to have further applications in similar evaluations.