Can a microscopic stochastic model explain the emergence of pain cycles in patients?

A stochastic model is here introduced to investigate the molecular mechanisms which trigger the perception of pain. The action of analgesic drug compounds is discussed in a dynamical context, where the competition with inactive species is explicitly accounted for. Finite size effects inevitably perturb the mean-field dynamics: Oscillations in the amount of bound receptors spontaneously manifest, driven by the noise which is intrinsic to the system under scrutiny. These effects are investigated both numerically, via stochastic simulations and analytically, through a large-size expansion. The claim that our findings could provide a consistent interpretative framework to explain the emergence of cyclic behaviors in response to analgesic treatments, is substantiated.Comment: J. Stat. Mech. (Proceedings UPON2008

Non-Gaussian fluctuations in stochastic models with absorbing barriers

The dynamics of a one-dimensional stochastic model is studied in presence of an absorbing boundary. The distribution of fluctuations is analytically characterized within the generalized van Kampen expansion, accounting for higher order corrections beyond the conventional Gaussian approximation. The theory is shown to successfully capture the non Gaussian traits of the sought distribution returning an excellent agreement with the simulations, for {\it all times} and arbitrarily {\it close} to the absorbing barrier. At large times, a compact analytical solution for the distribution of fluctuations is also obtained, bridging the gap with previous investigations, within the van Kampen picture and without resorting to alternative strategies, as elsewhere hypothesized.Comment: 2 figures, submitted to Phys. Rev. Let

Early results of fissurectomy and advancement flap for resistant chronic anal fissure without hypertonia of the internal anal sphincter

The aim of this study was to assess the efficacy of fissurectomy with skin advancement flap in healing chronic anal fissures without hypertonia of the internal anal sphincter. Twenty-six consecutive patients who failed healing after well-practiced topical medical therapy were enrolled. Anorectal manometry was performed preoperative and 6 months postoperatively. All patients were treated with fissurectomy and advancement flap through healthy skin tissue. All patients healed completely within 30 days from operation. The intensity and the duration of pain postdefecation was reduced significantly with respect to the preoperative values starting from the first defecation. One patient suffered urinary retention, two patients suffered infections, and two partial breakdowns were recorded. At 6 months the maximum resting pressure values were similar to those were detected preoperatively. One month after surgery, anal incontinence was reported in seven patients, four of whom complained about it preoperatively. At 12 months, only three subjects reported incontinence. No patients needed reoperation and no recurrences were detected. The fissurectomy, in combination with advancement flap, is a safe sphincter-saving procedure for the treatment of chronic anal fissures without hypertonia of internal anal sphincter that fails medical conservative treatment

Changes of Inflammatory Mediators in Obese Patients After Laparoscopic Cholecystectomy

Background Obesity is associated with the impairment of immunological functions. The aim of this study was to analyze some inflammatory mediators in obese subjects who underwent laparoscopic cholecystectomy. Methods Seventeen consecutive female patients with a BMI ranging from 35 to 45 kg/m2 (obese) and 17 consecutive female patients with BMI ranging from 20 to 25 kg/m2 (nonobese) were included in the study. All patients were affected by symptomatic gallbladder stone disease and underwent laparoscopic cholecystectomy. Changes in levels of leukocytes, neutrophils, IL-6, IL-10, leptin, and adiponectin were evaluated. Results We observed a significant increase in leukocyte and neutrophil levels in the obese subjects compared to the nonobese subjects. The serum levels of leptin and IL-6 were higher in the postoperative period (compared to the baseline values in both groups), and always higher in the obese. Both adiponectin and IL-10 increased in the postoperative period in nonobese subjects and was always higher than in the obese. Conclusions Obese patients have a stronger acute inflammatory response than do nonobese subjects in reaction to surgical stress

Using HoloLens Mixed Reality to research correlations between language and movement: a case study

Communication can be defined as the understanding and exchanging of meaningful messages. The role of communication is central to the lives of human beings as, everyday, we use language to interact with the world around us. Linguistic skills play a fundamental role in this scenario and Language Disorders (LD) are impairments that limit the processing of linguistic information. Early and accurate identification of LD is thus essential to promote lifelong learning and well-being. From an evolutionary perspective, some human language constructs evolved from an ancestral motor system and share the same neural pathways in the Broca’s area of the brain. This suggests a correlation between action and language. If such a relationship is well established and reliable, it would be possible to use the former as a marker of the latter. The hypothesis of our work, in a nutshell, is that movement can be a predictor of language. To study this correlation, we developed C(H)o(L)ordination, a Mixed Reality (MR) application for HoloLens 2. The application offers several activities based on visual stimuli involving motor movements, which tap on the same skills needed to perform some language tasks. We performed an exploratory study with N=22 users to test the application usability and user experience. The results suggest that C(H)o(L)ordination is a usable and powerful tool to gather insights on the ongoing debate about language evolution and language disorders

DFT insights into the oxygen-assisted selective oxidation of benzyl alcohol on manganese dioxide catalysts

The reactivity pattern of the MnO2 catalyst in the selective aerobic oxidation of benzyl alcohol is assessed by density functional theory (DFT) analysis of adsorption energies and activation barriers on a model Mn4O8 cluster. DFT calculations predict high reactivity of defective Mn(IV) sites ruling a surface redox mechanism, L-H type, involving gas-phase oxygen. Bare and promoted (i.e., CeOx and FeOx) MnOx materials with high surface exposure of Mn(IV) sites were synthesized to assess kinetic and mechanistic issues of the selective aerobic oxidation of benzyl alcohol on real catalysts (T, 333- 363K). According to DFT predictions, the experimental study shows: i) comparable activity of bare and promoted catalysts due to surface Mn(IV) sites; ii) the catalytic role of oxygen-atoms in the neighboring of active Mn(IV) sites; and iii) a 0th-order dependence on alcohol concentration, diagnostic of remarkable influence of adsorption phenomena on the reactivity pattern. Evidences of catalyst deactivation due to the over-oxidation of benzyl alcohol to benzoic acid, acting as poison of the active sites, are discussed

Zero and Finite Temperature Quantum Simulations Powered by Quantum Magic

We present a comprehensive approach to quantum simulations at both zero and finite temperatures, employing a quantum information theoretic perspective and utilizing the Clifford + $k$Rz transformations. We introduce the "quantum magic ladder", a natural hierarchy formed by systematically augmenting Clifford transformations with the addition of Rz gates. These classically simulable similarity transformations allow us to reduce the quantumness of our system, conserving vital quantum resources. This reduction in quantumness is essential, as it simplifies the Hamiltonian and shortens physical circuit-depth, overcoming constraints imposed by limited error correction. We improve the performance of both digital and analog quantum computers on ground state and finite temperature molecular simulations, not only outperforming the Hartree-Fock solution, but also achieving consistent improvements as we ascend the quantum magic ladder. By facilitating more efficient quantum simulations, our approach enables near-term and early fault-tolerant quantum computers to address novel challenges in quantum chemistry.Comment: 12 pages, 9 figure

A spatial model of autocatalytic reactions

Biological cells with all of their surface structure and complex interior stripped away are essentially vesicles - membranes composed of lipid bilayers which form closed sacs. Vesicles are thought to be relevant as models of primitive protocells, and they could have provided the ideal environment for pre-biotic reactions to occur. In this paper, we investigate the stochastic dynamics of a set of autocatalytic reactions, within a spatially bounded domain, so as to mimic a primordial cell. The discreteness of the constituents of the autocatalytic reactions gives rise to large sustained oscillations, even when the number of constituents is quite large. These oscillations are spatio-temporal in nature, unlike those found in previous studies, which consisted only of temporal oscillations. We speculate that these oscillations may have a role in seeding membrane instabilities which lead to vesicle division. In this way synchronization could be achieved between protocell growth and the reproduction rate of the constituents (the protogenetic material) in simple protocells.Comment: Submitted to Phys. Rev.