Multi-stable behavior at the microscopic length-scale is fundamental for phase transformation phenomena observed in many materials. These phenomena can be driven not only by external mechanical forces but are also crucially influenced by disorder and thermal fluctuations. Disorder, arising from structural defects or fluctuations in external stimuli, disrupts the homogeneity of the material and can significantly alter the system's response, often leading to the suppression of cooperativity in the phase transition.
View Article and Find Full Text PDFBecause of their capacity to bind metals, metal chelators are primarily employed for therapeutic purposes, but they can also find applications as colorimetric reagents and cleaning solutions as well as in soil remediation, electroplating, waste treatment, and so on. For instance, iron-chelation therapy, which is used to treat iron-overload disorders, involves removing excess iron from the blood through the use of particular molecules, like deferoxamine, that have the ability to chelate the metal. The creation of bioinspired and biodegradable chelating agents is a crucial objective that draws inspiration from natural products.
View Article and Find Full Text PDFThe separation of double-stranded peptide chains can occur in two ways: cooperatively or non-cooperatively. These two regimes can be driven either by chemical or thermal effects, or through non-local mechanical interactions. Here, we show explicitly that local mechanical interactions in biological systems may regulate the stability, the reversibility, and the cooperative/non-cooperative character of the debonding transition.
View Article and Find Full Text PDFBy extending the classical Peyrard-Bishop model, we are able to obtain a fully analytical description for the mechanical response of DNA under stretching at variable values of temperature, number of base pairs and intrachains and interchains bonds stiffness. In order to compare elasticity and temperature effects, we first analyze the system in the zero temperature mechanical limit, important to describe several experimental effects including possible hysteresis. We then analyze temperature effects in the framework of equilibrium Statistical Mechanics.
View Article and Find Full Text PDFWe propose a simple general framework to predict folding, native states, energy barriers, protein unfolding, as well as mutation induced diseases and other protein structural analyses. The model should not be considered as an alternative to classical approaches (Molecular Dynamics or Monte Carlo) because it neglects low scale details and rather focuses on global features of proteins and structural information. We aim at the description of phenomena that are out of the range of classical molecular modeling approaches due to the large computational cost: multimolecular interactions, cyclic behavior under variable external interactions, and similar.
View Article and Find Full Text PDFWe deduce a fully analytical model to predict the artifacts of the device handles in single molecule force spectroscopy experiments. As we show, neglecting the handle stiffness can lead to crucial overestimation or underestimation of the stability properties and unfolding thresholds of multistable molecules.
View Article and Find Full Text PDFObjective: This project of the International Society for Gynecologic Endoscopy (ISGE) had the objective to review the literature and provide recommendations on the occult sarcoma risk assessment in patients who are candidates for minimally invasive gynecological surgery involving intra-abdominal electromechanical tissue morcellation.
Study Design: The ISGE Task Force for Estimation of the Risk in Endoscopic Morcellation initially defined key topics and clinical questions which may guide a comprehensive preoperative patient assessment. A literature search within the Medline/PubMed and Cochrane Database was carried out using keywords "morcellation", "uterine fibroids", "uterine sarcoma", "myomectomy" and "hysterectomy".
Femtosecond stimulated Raman microscopy (FSRM) is a nonlinear technique for rapid broadband Raman imaging. It utilizes a few femtosecond probe pulse and a narrow bandwidth pump pulse. Using a fast (20 kHz) multi-channel detector, stimulated Raman spectra can be recorded with an acquisition time as short as 0.
View Article and Find Full Text PDFWe have used polarized confocal Raman microspectroscopy and scanning near-field optical microscopy with a resolution of 60 nm to characterize photoinscribed grating structures of azobenzene doped polymer films on a glass support. Polarized Raman microscopy allowed determining the reorientation of the chromophores as a function of the grating phase and penetration depth of the inscribing laser in three dimensions. We found periodic patterns, which are not restricted to the surface alone, but appear also well below the surface in the bulk of the material.
View Article and Find Full Text PDFThe generation of Greenberger-Horne-Zeilinger (GHZ) states is a crucial problem in quantum information. We derive general conditions for obtaining GHZ states as eigenstates of a Hamiltonian. We find that a necessary condition for an n-qubit GHZ state to be a nondegenerate eigenstate of a Hamiltonian is the presence of m-qubit couplings with m≥[(n+1)/2].
View Article and Find Full Text PDFPurpose: To compare two different imaging modalities, magnetic resonance (MR), and three-dimensional sonography (3DUS), in order to evaluate the specific role in preoperative work-up of deep infiltrating endometriosis.
Materials And Methods: 33 women with endometriosis underwent 3DUS and MR followed by surgical and histopathological investigations. Investigators described the disease extension in the following sites: torus uterinus and uterosacral ligaments (USL), vagina, rectovaginal-septum, rectosigmoid, bladder, ovaries.
Objectives: Conflicting opinions about laparoscopic myomectomy (LM) are still present regarding indications and risks related to reproductive outcome. We reviewed our 13-year experience (1) to identify risk factors or changes in methods that have improved our myomectomy technique and (2) to evaluate how the learning curve and improved surgical devices influenced our procedures, and (3) to study the myomectomy scar with a power color Doppler ultrasound (US).
Methods: From January 1991 to December 2003, we studied 332 patients who underwent laparoscopic myomectomy.