Ionomeric polymer‐metal composites (IPMC) are advanced materials designed to mimic biological systems. Their performance depends on various factors, including electrical stimulus intensity, membrane ...hydration, ionic migration, and Young's modulus. However, there is a lack of studies in the literature investigating how the water absorption capacity and elastic modulus change over time in IPMCs. Understanding the hydration level variation as a function of time is essential because as this parameter deviates, the ionic migration capacity and Young's modulus also change, altering the device's electromechanical efficiency over time. To address this research gap, Nafion/Pt‐based IPMC devices exchanged with four monovalent cations (H+, Li+, Na+, and K+) and one ionic liquid (1‐butyl‐3‐methylimidazolium—BMIM+) were prepared, and a comprehensive investigation on how the water absorption capacity and Young's modulus vary as a function of time, relative humidity (RH), and counterion size was performed. The results revealed that the water uptake capacity is significantly higher and occurs more rapidly at higher RH levels and when the counterion's ionic radius decreases. Consequently, the time required for the device to reach osmotic equilibrium can range from 40 to 270 min, depending on the RH and counterion used. Furthermore, it was observed that the first natural frequency and Young's modulus also exhibit time‐dependent behavior. Under constant RH conditions, the mechanical properties of the IPMC can vary by up to 50% in less than 60 min. Notably, the combined results from water uptake capacity, Young's modulus, electrochemical impedance spectroscopy, and electromechanical response analyses (including blocking force, displacement, displacement rate, current, coulombic efficiency, and voltage) suggest that a morphological transformation within the polymer is likely to occur once RH exceeds 60%. This finding strengthens the hypothesis that ion migration is mainly influenced by their movement through Nafion's ionomeric channels rather than the filling of ionic agglomerates.
Background: Respiratory allergies are inversely related to early acquisition of food‐borne and fecal‐oral infections, consumption of unpasteurized milk, early exposure to stables and high endotoxin ...concentrations in a farming environment. We tested therefore if infection by Salmonella in early life can protect from development of respiratory allergies later in life.
Methods: During 2003, we studied two groups of Sardinian children (age 6–18 years) who had been hospitalized before 4 years of age (during 1989–2001) with non‐typhoid salmonellosis (n = 148) or acute enteritis of nonbacterial etiology (NB‐enteritis) (n = 167). Allergic rhinoconjunctivitis (AR) and asthma were evaluated by telephonic interview with a ISAAC questionnaire; participants reporting AR and/or asthma were further examined through a complete diagnostic work‐up to objectively confirm or exclude current disease. Kaplan–Meier curves and Cox proportional hazard models were used to analyze the role of different types of enteritis on the risk of developing allergic rhinoconjunctivitis or asthma over time.
Results: Children who had been hospitalized with salmonellosis had a lower prevalence of allergic rhinoconjunctivitis (eight of 148, 5.4%vs 23 of 167, 13.8%; P = 0.019) or asthma (five of 148, 3.4%vs 21 of 167, 12.6%; P = 0.006) than those who had been hospitalized with NB‐enteritis. The proportional hazard of salmonellosis for asthma was 0.23 (95% CI: 0.08–0.67; P < 0.01) and for allergic rhinoconjunctivitis was 0.40 (95% CI: 0.17–0.95; P = 0.04), after adjusting for confounders.
Discussion: The strength of the observed associations suggests that Salmonella may contribute to shape the natural history of respiratory allergies. However, further studies are needed to test in other settings the association observed in Sardinian children. We speculate that clinical or subclinical infection by Salmonella may contribute to the atopy protective influence of a traditional farming environment or of areas endemic for food‐borne and fecal‐oral infections. Food hygiene and prevention of salmonellosis must remain however a public health priority.
Background
This study aimed to analyse the feasibility and acute toxicity of radical hypo-fractionated radiotherapy (RT) for elderly patients with non-small-cell lung cancer (NSCLC).
Patients and ...methods
We conducted a retrospective evaluation of treatment with volumetric modulated arc therapy (VMAT) of elderly patients affected by stage III inoperable NSCLC. The dose prescription was 56 Gy in 20 fractions, 55 Gy in 22 fractions, or 50 Gy in 20 fractions. Target volume included only the primary lesion and the infiltrated lymph nodes. The primary end point was acute and late toxicity, while secondary end points were progression-free survival (PFS), and overall survival (OS).
Results
In all, 41 patients were included in this analysis. The mean age of the patients was 78.6 years, and 22 patients had staged IIIA while 19 patients had stage IIIB disease. All but one patient had pathological nodal involvement; 15 patients received chemotherapy before RT. Acute grade 1–2 toxicity was recorded in 25 (61%) patients. Late toxicity was recorded in 13 (32%) patients. No cases of G3 or G4 toxicity were recorded. Complete response was obtained in two (5%) patients, 26 (63%) showed a partial response, and two (5%) experience disease progression. At a mean follow-up of 9.9 months (range, 1.1–25.4), 17 patients had died from disease progression, one died from other causes, and 23 were alive. Median OS was 13.7 ± 1.5 months (95% CI: 10.7–16.7), OS at 12 and 18 months was 51.3 ± 9.5% and 35.1 ± 10.1%, respectively. Median PFS was 13.7 ± 2.3 months (95% CI: 9.1–18.2), and PFS at 12 and 18 months was 50.1 ± 9.9% and 38.9 ± 10.4%, respectively.
Conclusion
Radical hypo-fractionated VMAT is a promising treatment for locally advanced NSCLC in the elderly. The use of hypo-fractionated radiotherapy for lung cancer in older patients can be considered a valuable approach, particularly for patients with poor performance status or refusing other treatment approaches.
In pediatrics the routine use of whole-cell vaccines against
Bordetella pertussis
has been a matter of continuous debate.
1
–
4
Acellular vaccines, consisting of purified proteins, have been in use ...for the primary immunization of two-year-old children in Japan since 1981.
5
,
6
Two acellular vaccines were evaluated in a randomized clinical trial in Sweden,
7
but the results left unanswered questions about the efficacy of the vaccines in infants, particularly in relation to that of whole-cell vaccines.
In Italy, vaccination of infants against diphtheria, tetanus, poliomyelitis, and hepatitis B is mandatory, but vaccination against pertussis is not. The rate of vaccination against . . .
Nafion/Pt-based ionic polymer metal composites can be considered smart materials with characteristics that allow it to be used as soft actuators. Its working mechanism is based on solvated ...counterions moving through hydrophilic sites of the polymer membrane, making it an electrochemical device. Since a minimum of 2 V is needed to actuate, water electrolysis is a drawback that must be overcome, once its occurrence inhibits the properly working of ionomeric polymer/metal composite (IPMC). With individually four distinct counterions incorporated H
+
, Li
+
, Na
+
and BMIM
+
— an organic cation from ionic liquid 1-butyl-3-methyl-imidazolium chloride — Nafion/Pt-based IPMCs had their electrochemical properties investigated through cyclic voltammetry, multi-step chronoamperometry and electrical impedance, as well as mass change during exhaustive actuation cycles and their chemical affinity with hydrophilic sites were analysed by quantum mechanics simulation. From the collected data, it was possible to infer that the physical-chemical aspects of counterions play a key role in device-measured property, and BMIM
+
prevented early water electrolysis, providing electrochemical stability to the device. Real-time mass-monitored actuation shows that water loss occurs excessively on smaller radius counterions and although the fast reabsorption kinetics, molecular diffusion to the innermost regions of the membrane is slow and does not lead to a recovery of device’s performance. Electrochemical impedance spectroscopy data corroborate the fact that mass transport is strongly affected by both the limited ionomeric channel width and the interaction between the species and the Nafion side chains.
PDF