Mechanical correlates of dyspnea in bronchial asthma.

We hypothesized that dyspnea and its descriptors, that is, chest tightness, inspiratory effort, unrewarded inspiration, and expiratory difficulty in asthma reflect different mechanisms of airflow obstruction and their perception varies with the severity of bronchoconstriction. Eighty-three asthmatics were studied before and after inhalation of methacholine doses decreasing the 1-sec forced expiratory volume by ~15% (mild bronchoconstriction) and ~25% (moderate bronchoconstriction). Symptoms were examined as a function of changes in lung mechanics. Dyspnea increased with the severity of obstruction, mostly because of inspiratory effort and chest tightness. At mild bronchoconstriction, multivariate analysis showed that dyspnea was related to the increase in inspiratory resistance at 5 Hz (R 5) (r (2) = 0.10, P = 0.004), chest tightness to the decrease in maximal flow at 40% of control forced vital capacity, and the increase in R 5 at full lung inflation (r (2) = 0.15, P = 0.006), inspiratory effort to the temporal variability in R 5-19 (r (2) = 0.13, P = 0.003), and unrewarded inspiration to the recovery of R 5 after deep breath (r (2) = 0.07, P = 0.01). At moderate bronchoconstriction, multivariate analysis showed that dyspnea and inspiratory effort were related to the increase in temporal variability in inspiratory reactance at 5 Hz (X 5) (r (2) = 0.12, P = 0.04 and r (2) = 0.18, P < 0.001, respectively), and unrewarded inspiration to the decrease in X 5 at maximum lung inflation (r (2) = 0.07, P = 0.04). We conclude that symptom perception is partly explained by indexes of airway narrowing and loss of bronchodilatation with deep breath at low levels of bronchoconstriction, but by markers of ventilation heterogeneity and lung volume recruitment when bronchoconstriction becomes more severe

Arterial stiffness, endothelial and cognitive function in subjects with type 2 diabetes in accordance with absence or presence of diabetic foot syndrome

Abstract Background Endothelial dysfunction is an early marker of cardiovascular disease so endothelial and arterial stiffness indexes are good indicators of vascular health. We aimed to assess whether the presence of diabetic foot is associated with arterial stiffness and endothelial function impairment. Methods We studied 50 subjects with type 2 diabetes mellitus and diabetic foot syndrome (DFS) compared to 50 diabetic subjects without diabetic foot, and 53 patients without diabetes mellitus, by means of the mini mental state examination (MMSE) administered to evaluate cognitive performance. Carotid-femoral pulse wave velocity (PWV) and augmentation index (Aix) were also evaluated by Applanation tonometry (SphygmoCor version 7.1), and the RH-PAT data were digitally analyzed online by Endo-PAT2000 using reactive hyperemia index (RHI) values. Results In comparison to diabetic subjects without diabetic foot the subjects with diabetic foot had higher mean values of PWV, lower mean values of RHI, and lower mean MMSE. At multinomial logistic regression PWV and RHI were significantly associated with diabetic foot presence, whereas ROC curve analysis had good sensitivity and specificity in arterial PWV and RHI for diabetic foot presence. Conclusions Pulse wave velocity and augmentation index, mean RHI values, and mean MMSE were effective indicators of diabetic foot. Future research could address these issues by means of longitudinal studies to evaluate cardiovascular event incidence in relation to arterial stiffness, endothelial and cognitive markers

Ventilation heterogeneity in obesity.

Obesity is associated with important decrements in lung volumes. Despite this, ventilation remains normally or near normally distributed at least for moderate decrements in functional residual capacity (FRC). We tested the hypothesis that this is because maximum flow increases presumably as a result of an increased lung elastic recoil. Forced expiratory flows corrected for thoracic gas compression volume, lung volumes, and forced oscillation technique at 5-11-19 Hz were measured in 133 healthy subjects with a body mass index (BMI) ranging from 18 to 50 kg/m(2). Short-term temporal variability of ventilation heterogeneity was estimated from the interquartile range of the frequency distribution of the difference in inspiratory resistance between 5 and 19 Hz (R5-19_IQR). FRC \% predicted negatively correlated with BMI (r = -0.72, P < 0.001) and with an increase in slope of either maximal (r = -0.34, P < 0.01) or partial flow-volume curves (r = -0.30, P < 0.01). Together with a slight decrease in residual volume, this suggests an increased lung elastic recoil. Regression analysis of R5-19_IQR against FRC \% predicted and expiratory reserve volume (ERV) yielded significantly higher correlation coefficients by nonlinear than linear fitting models (r(2) = 0.40 vs. 0.30 for FRC \% predicted and r(2) = 0.28 vs. 0.19 for ERV). In conclusion, temporal variability of ventilation heterogeneities increases in obesity only when FRC falls approximately below 65\% of predicted or ERV below 0.6 liters. Above these thresholds distribution is quite well preserved presumably as a result of an increase in lung recoil

Solvency Effects on Biopolymer Interactions in Pectin Gels

Low methoxyl pectin (LMP) is a biopolymer widely used in the food and pharmaceutical industries for its gelling properties mediated via divalent ions. Gel formation of LMP strongly depends on both the chemical characteristics of the polymer and the environmental condi- tions of gel preparation. Unlike high methoxyl pectin, LMP does not require co-solutes to induce gelation, i.e., sugars, allowing the possibil- ity of reducing the calorie content of foods requiring a gel texture. In addition, there is increased interest in LMP as fat substitute in con- fectionery products. Although some work has been done on highly fractionated LMP with Ca2+, virtually no detailed work seems to have been reported on commercial LMP + Ca2+ + high sugar con- centrations, despite the fact that work on fractionated LMP suggests that the presence of sucrose, for example, can have a significant ef- fect on LMP gelation. This thesis couples rheology and dynamic light scattering (DLS) to investigate the process of gelation of LMP samples in presence of a range of different sugars (at 60 wt. % ) in- cluding fructose, D-psicose, sorbitol and invert sugar (1:1 M fructose and glucose). In addition, to compare with the results of previous studies [1] [2], LMP gelation in the presence of 40 wt. % sorbitol was also investigated. Selected systems were also studied via com- plementary static scattering techniques including a novel rheospeckle set-up that allows simultaneous rheology and DLS analysis. Rheolog- ical characterization of both the sol and gel states of LMP prepared in water (i.e., without added sugars) show agreement with studies performed in the past. However, small angle light scattering revealed the presence of abnormally large structures (compared to conventional pectin molecule dimensions) that may coexist with smaller ones de- tected via static light scattering. These large pectin molecular struc- tures may explain some unexpected results obtained for LMP gels prepared in high concentrations of sugars. Thus, although some sug- ars tend to speed up gelation, at certain calcium concentrations the mixture of larger and smaller structures appears to get trapped in a non-equilibrium gel state, that can only be resolved be re-heating (gel melting) and re-cooling. In other words, the normal thermoreversibil- ity of LMP gels is disrupted. After the thermal cycling such gels increase in strength. However, other sugars seem to disrupt gelation completely so that this effect is not seen. The effects of the different sugars are probably related to different specific sugar-sugar interac- tions that depend on their exact stereochemistry

Implementazione di un sistema automatizzato per la gestione della logistica inbound di materiali critici

L’obbiettivo di questa tesi è quello di agevolare il sistema preesistente sulla gestione dei componenti considerati critici ai fini dell’assemblaggio e mobilitazione dei macchinari. La trattazione è divisa in due parti principali: una teorica, utile ad agevolare il lettore nella comprensione delle attività svolte, inerente ai primi due capitoli, ed una operativa, che si concentra sul confronto tra il sistema di gestione del materiale critico precedentemente presente in azienda e il sistema elaborato ai fini della semplificazione nella gestione del lavoro. Infine, sono stati analizzati i risultati ottenuti a seguito della stesura dei due programmi, evidenziando in particolar modo i risvolti migliorativi ottenuti in favore dei sollecitatori di materiale. Andando, prima, ad evidenziare il grande risparmio di tempo derivato dallo svincolamento di una risorsa dalla gestione del File dei Mancanti Critici e, in secondo luogo, illustrando i vantaggi economici derivanti sia dallo stesso risparmio di tempo-uomo sia da un sollecito del materiale più mirato. Analizzando i dati ottenuti è risultato che l’automatizzazione del sistema ha ridotto il numero di volte in cui i componenti critici erano mancanti del 50% rispetto quelli non critici

Nanoemulsion-Based Delivery Systems for Polyunsaturated (\u3c9-3) Oils: Formation Using a Spontaneous Emulsification Method

Nanoemulsion-based delivery systems are finding increasing utilization to encapsulate lipophilic bioactive components in food, personal care, cosmetic, and pharmaceutical applications. In this study, a spontaneous emulsification method was used to fabricate nanoemulsions from polyunsaturated (omega-3) oils, that is, fish oil. This low-energy method relies on formation of fine oil droplets when an oil/surfactant mixture is added to an aqueous solution. The influence of surfactant-to-oil ratio (SOR), oil composition (lemon oil and MCT), and cosolvent composition (glycerol, ethanol, propylene glycol, and water) on the formation and stability of the systems was determined. Optically transparent nanoemulsions could be formed by controlling SOR, oil composition, and aqueous phase composition. The spontaneous emulsification method therefore has considerable potential for fabricating nanoemulsion-based delivery systems for incorporating polyunsatured oils into clear food, personal care, and pharmaceutical products

A multi-scale numerical approach to study monoclonal antibodies in solution

Developing efficient and robust computational models is essential to improve our understanding of protein solution behavior. This becomes particularly important to tackle the high-concentration regime. In this context, the main challenge is to put forward coarse-grained descriptions able to reduce the level of detail, while retaining key features and relevant information. In this work, we develop an efficient strategy that can be used to investigate and gain insight into monoclonal antibody solutions under different conditions. We use a multi-scale numerical approach, which connects information obtained at all-atom and amino-acid levels to bead models. The latter has the advantage of reproducing the properties of interest while being computationally much faster. Indeed, these models allow us to perform many-protein simulations with a large number of molecules. We can, thus, explore conditions not easily accessible with more detailed descriptions, perform effective comparisons with experimental data up to very high protein concentrations, and efficiently investigate protein–protein interactions and their role in phase behavior and protein self-assembly. Here, a particular emphasis is given to the effects of charges at different ionic strengths

Probing Cage Relaxation in Concentrated Protein Solutions by X-Ray Photon Correlation Spectroscopy

Diffusion of proteins on length scales of their size is crucial for understanding the machinery of living cells. X-ray photon correlation spectroscopy (XPCS) is currently the only way to access long-time collective diffusion on these length scales, but radiation damage so far limits the use in biological systems. We apply a new approach to use XPCS to measure cage relaxation in crowded α-crystallin solutions. This allows us to correct for radiation effects, obtain missing information on long time diffusion, and support the fundamental analogy between protein and colloid dynamical arrest