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1.
Heliyon ; 9(9): e19120, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37809762

RESUMO

The importance of building ventilation in avoiding long-distance airborne transmission has been highlighted with the advent of the COVID-19 pandemics. Among others, school environments, in particular classrooms, present criticalities in the implementation of ventilation strategies and their impact on indoor air quality and risk of contagion. In this work, three naturally ventilated school buildings located in northern Italy have undergone monitoring at the end of the heating season. Environmental parameters, such as CO2 concentration and indoor/outdoor air temperature, have been recorded together with the window opening configurations to develop a two-fold analysis: i) the estimation of real air change rates through the transient mass balance equation method, and ii) the individual infection risk via the Wells-Riley equation. A strong statistical correlation has been found between the air change rates and the windows opening configuration by means of a window-to-volume ratio between the total opening area and the volume of the classroom, which has been used to estimate the individual infection risk. Results show that the European Standard recommendation for air renewal could be achieved by a window opening area of at least 1.5 m2, in the most prevailing Italian classrooms. Furthermore, scenarios in which the infector agent is a teacher show higher individual infection risk than those in which the infector is a student. In addition, the outcomes serve school staff as a reference to ensure adequate ventilation in classrooms and keep the risk of infection under control based on the number of the students and the volume of the classroom.

2.
Ann Anat ; 250: 152144, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37574174

RESUMO

Articular cartilage degradation due to injury, disease and aging is a common clinical issue as current regenerative therapies are unable to fully replicate the complex microenvironment of the native tissue which, being avascular, is featured by very low ability to self-regenerate. The extracellular matrix (ECM), constituting almost 90% of the entire tissue, plays a critical role in its function and resistance to compressive forces. In this context, the current tissue engineering strategies are only partially effective in restoring the biology and function of the native tissue. A main issue in tissue regeneration is treatment failure due to scarce integration of the engineered construct, often following a gradual detachment of the graft. In this scenario, we aimed to create an adhesive patch able to adequately support cartilage regeneration as a promising tool for the treatment of cartilage injuries and diseases. For this, we produced an engineered construct composed of decellularized ECM (dECM) obtained from horse joint cartilage, to support tissue regeneration, coupled with a Silk-Elastin-Like Proteins (SELP) hydrogel, which acts as a biological glue, to guarantee an adequate adherence to the host tissue. Following the production of the two biomaterials we characterized them by assessing: 1) dECM morphological, chemical, and ultrastructural features along with its capability to support chondrocyte proliferation, specific marker expression and ECM synthesis; 2) SELP microarchitecture, cytocompatibility and mechanical properties. Our results demonstrated that both materials hold unique properties suitable to be exploited to produce a tailored microenvironment to support cell growth and differentiation providing a proof of concept concerning the in vitro biological and mechanical efficacy of the construct. The SELP hydrogel displayed a very interesting physical behavior due to its high degree of resistance to mechanical stress, which is generally associated with physiological mechanical load during locomotion. Intriguingly, the shear-thinning behavior of the hydrogel may also make it suitable to be applied and spread over non-homogeneous surfaces, therefore, we hypothesize that the hybrid biomaterial proposed may be a real asset in the treatment of cartilage defects and injuries.


Assuntos
Cartilagem Articular , Animais , Cavalos , Hidrogéis/análise , Hidrogéis/química , Hidrogéis/metabolismo , Elastina/análise , Elastina/metabolismo , Seda/análise , Seda/metabolismo , Biomimética , Engenharia Tecidual/métodos , Matriz Extracelular/metabolismo , Materiais Biocompatíveis/metabolismo , Condrócitos , Alicerces Teciduais/química
3.
Nat Commun ; 13(1): 7390, 2022 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-36450728

RESUMO

Mercury's southern inner magnetosphere is an unexplored region as it was not observed by earlier space missions. In October 2021, BepiColombo mission has passed through this region during its first Mercury flyby. Here, we describe the observations of SERENA ion sensors nearby and inside Mercury's magnetosphere. An intermittent high-energy signal, possibly due to an interplanetary magnetic flux rope, has been observed downstream Mercury, together with low energy solar wind. Low energy ions, possibly due to satellite outgassing, were detected outside the magnetosphere. The dayside magnetopause and bow-shock crossing were much closer to the planet than expected, signature of a highly eroded magnetosphere. Different ion populations have been observed inside the magnetosphere, like low latitude boundary layer at magnetopause inbound and partial ring current at dawn close to the planet. These observations are important for understanding the weak magnetosphere behavior so close to the Sun, revealing details never reached before.

4.
Space Sci Rev ; 217(1): 11, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33487762

RESUMO

The ESA-JAXA BepiColombo mission to Mercury will provide simultaneous measurements from two spacecraft, offering an unprecedented opportunity to investigate magnetospheric and exospheric particle dynamics at Mercury as well as their interactions with solar wind, solar radiation, and interplanetary dust. The particle instrument suite SERENA (Search for Exospheric Refilling and Emitted Natural Abundances) is flying in space on-board the BepiColombo Mercury Planetary Orbiter (MPO) and is the only instrument for ion and neutral particle detection aboard the MPO. It comprises four independent sensors: ELENA for neutral particle flow detection, Strofio for neutral gas detection, PICAM for planetary ions observations, and MIPA, mostly for solar wind ion measurements. SERENA is managed by a System Control Unit located inside the ELENA box. In the present paper the scientific goals of this suite are described, and then the four units are detailed, as well as their major features and calibration results. Finally, the SERENA operational activities are shown during the orbital path around Mercury, with also some reference to the activities planned during the long cruise phase.

5.
J Appl Anim Welf Sci ; 23(3): 366-377, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32441218

RESUMO

In the equestrian world, two different types of management can be distinguished: traditional management and natural boarding. The aim of this research was to compare hormonal, hematological and immunological parameters of 47 horses kept in these two different managements. Blood and horsehair of the horses were sampled to determine DHEA (dehydroepiandrosterone) and cortisol concentration through RIA. Moreover, blood count was conducted, and flow cytometry was employed to phenotype lymphocyte subpopulations. Results showed that, in horsehair, DHEA concentration was significantly higher in natural horses, whereas cortisol concentration and cortisol/DEHA ratio significantly lower. These hormonal parameters are used to assess the stress condition and the welfare of animals. The most favorable endocrine framework found in horses kept in natural boarding suggests that this management conveys most with ethological and physiological needs of the species. The research underlines the need of a modification of horses' husbandry systems. For the first time, this study validates the assay of DHEA in horsehair.


Assuntos
Desidroepiandrosterona/análise , Cavalos/fisiologia , Abrigo para Animais , Hidrocortisona/análise , Estresse Fisiológico , Criação de Animais Domésticos , Bem-Estar do Animal , Animais , Feminino , Cabelo/química , Hormônios , Cavalos/sangue , Cavalos/imunologia , Masculino
6.
Transl Med UniSa ; 17: 12-18, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30050875

RESUMO

MicroRNAs (microRNAs or miRs) are small, non-coding RNAs that control gene expression by binding to and repressing specific mRNA target and have emered as powerful regulators of many biological processes. Understanding miRNAs-biology and functions may be pivotal to get a better insight into pathophysiological mechanisms responsible for a large number of morbid conditions and may lay the foundations for the development of novel therapeutic interventions. Moreover, besides their intracellular functions, miRs are present in the human circulation in a remarkably stable cell-free form, and their plasmatic levels have been proposed as biomarkers for several pathological conditions. The present review aims to summarize the current evidences with regard to biological role of miRNAs in cardiovascular system and their involvement in the pathogenesis of cardiovascular diseases including atherosclerosis, heart failure and pathological heart and vascular remodelling and to highlight their potential use as novel biomarkers and as therapeutic targets in cardiac and vascular diseases.

7.
Vet J ; 211: 45-51, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-27033593

RESUMO

Inflammation plays an important role in the pathogenesis of congestive heart failure (CHF). In humans with CHF, increased production and high plasma concentrations of tumour necrosis factor-α (TNF-α), interleukin (IL)-6, IL-1, IL-8 and transforming growth factor-ß (TGF-ß) have been associated with disease progression and a negative prognosis. The aim of this study was to investigate whether differences in cytokine blood mRNA expression exist between clinically healthy dogs and dogs with myxomatous mitral valve disease (MMVD); to determine if the expression was related to the severity of MMVD, and to detect any correlations with echocardiographic parameters of cardiac remodelling. Twenty-three dogs with MMVD of varying severity and six clinically healthy dogs were included in the study. Whole blood samples were obtained for measurement of mRNA expression of IL-1α, IL-1ß, IL-6, IL-8, TGF-ß1, TNF-α by reverse transcriptase-PCR (RT-PCR). There were statistically significant differences between clinically healthy dogs and dogs with MMVD for IL-8 and TGF-ß1 gene expression. IL-8 expression increased with increasing MMVD severity and TGF-ß1 expression was higher in asymptomatic dogs with echocardiographic signs of cardiac remodelling (American College Veterinary Internal Medicine class B2) than in all other groups. These results could suggest the involvement of these cytokines at different stages of the disease.


Assuntos
Citocinas/genética , Doenças do Cão/fisiopatologia , Expressão Gênica , Doenças das Valvas Cardíacas/veterinária , Leucócitos Mononucleares/metabolismo , Função Ventricular Esquerda , Remodelação Ventricular , Animais , Citocinas/metabolismo , Doenças do Cão/genética , Doenças do Cão/metabolismo , Cães , Ecocardiografia/veterinária , Feminino , Doenças das Valvas Cardíacas/genética , Doenças das Valvas Cardíacas/metabolismo , Doenças das Valvas Cardíacas/fisiopatologia , Masculino , Valva Mitral/patologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterinária
10.
Vet Microbiol ; 168(2-4): 357-64, 2014 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-24332702

RESUMO

The systemic and respiratory local immune response induced by the intradermal administration of a commercial inactivated Mycoplasma hyopneumoniae whole-cell vaccine (Porcilis(®) MHYO ID ONCE - MSD AH) in comparison with two commercial vaccines administered via the intramuscular route and a negative control (adjuvant only) was investigated. Forty conventional M. hyopneumoniae-free pigs were randomly assigned to four groups (ten animals each): Group A=intradermal administration of the test vaccine by using the needle-less IDAL(®) vaccinator at a dose of 0.2 ml; Group B=intramuscular administration of a commercially available vaccine (vaccine B); Group C=intramuscular administration of the adjuvant only (2 ml of X-solve adjuvant); Group D=intramuscular administration of a commercially available vaccine (vaccine D). Pigs were vaccinated at 28 days of age. Blood and bronchoalveolar lavage (BAL) fluid samples were collected at vaccination (blood only), 4 and 8 weeks post-vaccination. Serum and BAL fluid were tested for the presence of antibodies by ELISA test. Peripheral blood monomorphonuclear cells (PBMC) were isolated to quantify the number of IFN-γ secreting cells by ELISpot. Moreover, cytokine gene expression from the BAL fluid was performed. Total antibodies against M. hyopneumoniae and specific IgG were detected in serum of intradermally and intramuscularly (vaccine B only) vaccinated pigs at 4 and 8 weeks post-vaccination. M. hyopneumoniae specific IgA were detected in BAL fluid from vaccinated animals (Groups A and B) but not from controls and animals vaccinated with the bacterin D (p<0.05). Significantly higher gene expression of IL-10 was observed in the BAL fluid at week 8 post-vaccination in the intradermally vaccinated pigs (p<0.05). The results support that the intradermal administration of an adjuvanted bacterin induces both systemic and mucosal immune responses. Moreover, the intramuscularly administered commercial vaccines each had a different ability to stimulate the immune response both systemically and locally.


Assuntos
Vacinas Bacterianas/administração & dosagem , Mycoplasma hyopneumoniae/imunologia , Pneumonia Suína Micoplasmática/imunologia , Pneumonia Suína Micoplasmática/prevenção & controle , Animais , Anticorpos Antibacterianos/sangue , Anticorpos Antibacterianos/imunologia , Vacinas Bacterianas/imunologia , Líquido da Lavagem Broncoalveolar/imunologia , Imunoglobulina A/imunologia , Injeções Intradérmicas , Injeções Intramusculares , Interferon gama/imunologia , Interleucina-10/genética , Interleucina-10/imunologia , Leucócitos Mononucleares/imunologia , Masculino , Sus scrofa/imunologia , Suínos/imunologia , Vacinação/métodos , Vacinas de Produtos Inativados/administração & dosagem , Vacinas de Produtos Inativados/imunologia
11.
Animal ; 6(6): 902-8, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22558960

RESUMO

The effects of dietary nucleotide supplementation from 9 days of age until the end of post-weaning on piglets hormonal and immune responses and on growth performance were investigated. During lactation (days 9 to 21) and post-weaning (days 22 to 55) 10 [HBI Fomeva11 × (Large White × Landrace)] litters (n = 108 piglets) had ad libitum access to two standard diets, both supplemented with 0% (T0 group) or 0.1% (T1 group) of yeast extract nucleotides. BW of piglets at days 21 (P < 0.10), 35 and 55 (P < 0.05) was greater in T1 compared with T0. Feed intake was not different between groups (P > 0.05). Cortisol content was lower in T1 than in T0 at days 28 and 35 (P < 0.05), whereas growth hormone was lower at day 35 (P < 0.05). Levels of IGF-1 were similar across groups (P > 0.05). Nucleotide-supplemented diets increased lymphocyte subpopulation CD4-CD8+high at days 21 and 35 (P < 0.05), whereas CD4+CD8- cells were higher in T1 than in T0 at day 21 (P < 0.05). Peripheral blood mononuclear cells cytokine expression was influenced by dietary nucleotide supplementation. At weaning, interleukin (IL)-6 and IL-1ß expression was lower (P < 0.05) in T1 compared with T0, whereas the expression of interferon (IFN)-γ and IL-10 was higher (P < 0.05). At day 28, piglets in T1 showed higher values of tumor necrosis factor (TNF)-α expression than T0 and lower values of IL-10 expression (P < 0.05). Dietary nucleotide supplementation had a suppressive effect on IL-6 and IL-10 expression (P < 0.05) at day 35. On the contrary, the expression of IFN-γ, TNF-α and IL-1ß was enhanced (P < 0.05). In conclusion, these results suggest that starting a dietary nucleotide supplementation before weaning can improve the adaptive capabilities of weaned piglets to the stressors, enhancing the growth performance.


Assuntos
Criação de Animais Domésticos , Animais Lactentes/crescimento & desenvolvimento , Suplementos Nutricionais/análise , Nucleotídeos/administração & dosagem , Sus scrofa/crescimento & desenvolvimento , Leveduras/química , Ração Animal/análise , Animais , Animais Lactentes/imunologia , Animais Lactentes/fisiologia , Feminino , Expressão Gênica , Hormônio do Crescimento/sangue , Hidrocortisona/sangue , Fator de Crescimento Insulin-Like I/análise , Interferon gama/sangue , Interferon gama/metabolismo , Interleucinas/sangue , Interleucinas/metabolismo , Lactação , Masculino , Sus scrofa/imunologia , Sus scrofa/fisiologia , Linfócitos T/imunologia , Fator de Necrose Tumoral alfa/sangue , Fator de Necrose Tumoral alfa/metabolismo , Desmame
12.
Philos Trans A Math Phys Eng Sci ; 369(1944): 2329-36, 2011 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-21536580

RESUMO

The effect of a slit-like confinement on the relaxation dynamics of DNA is studied via a mesoscale model in which a bead and spring model for the polymer is coupled to a particle-based Navier-Stokes solver (multi-particle collision dynamics). The confinement is found to affect the equilibrium stretch of the chain when the bulk gyration radius is comparable to or smaller than the channel height and our data are in agreement with the (R(g,bulk)/h)(1/4) scaling of the polymer extension in the wall tangential direction. Relaxation simulation at different confinements indicates that, while the overall behaviour of the relaxation dynamics is similar for low and strong confinements, a small, but significant, slowing of the far-equilibrium relaxation is found as the confinement increases.


Assuntos
Simulação por Computador , DNA/química , DNA/ultraestrutura , Microfluídica/métodos , Modelos Químicos , Modelos Moleculares , Movimento (Física) , Conformação de Ácido Nucleico , Estresse Mecânico
13.
Res Vet Sci ; 90(1): 64-71, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20546827

RESUMO

The immune response induced by intradermal vaccination using a needle-less device was evaluated in conventional pigs in comparison with the more conventional intramuscular vaccination; to this purpose, vaccination against Aujeszky's Disease (AD) was used as a model of antiviral immunity. Two groups of pigs (n=10 each) were vaccinated 4 weeks apart respectively by the intramuscular (IM group) and intradermal route (ID group; needle-less I.D.A.L.® vaccinator) with an AD modified live virus. Ten pigs injected with the vaccine adjuvant only were kept as sham-vaccinated controls (C group). On blood samples collected at 0, 2, 4, 5, 6 and 7 weeks post-vaccination (PV) ADV-specific virus neutralizing (VN) antibodies, IFN-γ secreting cells (SC), lymphocyte subsets and IFN-γ gene expression in PBMC were evaluated. VN antibodies increased after the 1st vaccination and peaked after the 2nd vaccination in both vaccinated groups. Also IFN-γ SC reached maximum levels in both groups after administration of the booster dose. Pigs in the control group remained negative for both parameters throughout the study. Flow cytometry showed persistently higher levels of CD3-CD8α+ Natural Killer cells in both vaccinated pigs. The ID group showed an earlier and regulated activation characterized by an increase of cytotoxic CD8ß+ T lymphocytes and CD25+ cells after the boosting dose. No statistically significant differences between treated and control groups were detected for memory CD4+CD8α+(low) T cells. Upregulation of IFN-γ gene expression in PBMC was detected in ID and IM pigs after both vaccine administrations, although at a different extent. Overall, the results showed that the intradermal vaccine delivery by a needle-less device can prime a strong humoral and cellular immune response comparable to that obtained by the intramuscular vaccination.


Assuntos
Pseudorraiva/prevenção & controle , Doenças dos Suínos/prevenção & controle , Vacinação/veterinária , Vacinas Virais/imunologia , Animais , Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Regulação da Expressão Gênica/imunologia , Injeções Intradérmicas , Injeções Intramusculares , Interferon gama/genética , Interferon gama/metabolismo , Leucócitos Mononucleares/metabolismo , Suínos , Vacinação/métodos , Vacinas Virais/administração & dosagem
14.
Vet Res Commun ; 34 Suppl 1: S63-7, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20512626

RESUMO

Flow cytometry is a useful tool to determine both the phenotype and function of immune cells during vaccination and viral infection. Since cytokine release is a hallmark of cell activation, detection of intracellular interferon (IFN)gamma in cytotoxic CD8alpha+ cells under physiological conditions and after Aujeszky's Disease Virus (ADV)- or Porcine Circovirus type 2 (PCV2)-swine interaction was carried out. Blood samples were collected from healthy 10-month-old pigs, ADV- or PCV2-vaccinated pigs, and PCV2-infected pigs; the levels of total IFNgamma+ and CD8alpha+IFNgamma+ cells were evaluated after PMA-ionomycin and virus-specific in vitro stimulation. High CD8alpha+IFNgamma+ cell levels were detected in adult pigs, whereas lower virus-specific cell fractions were observed after ADV or PCV2 vaccination as well as after PCV2 natural infection due to restricted activation. Such results support the use of cytokine intracellular staining to monitor virus-specific cell-mediated immunity.


Assuntos
Antígenos Virais/fisiologia , Circovirus/fisiologia , Herpesvirus Suídeo 1/fisiologia , Interferon gama/metabolismo , Leucócitos Mononucleares/virologia , Animais , Células Cultivadas , Circovirus/classificação , Citometria de Fluxo , Interferon gama/genética , Ionomicina , Pseudorraiva/prevenção & controle , Suínos , Vacinas Virais/imunologia
15.
Acta Biomater ; 6(3): 1014-24, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19800423

RESUMO

Anodic spark deposition (ASD) is an attractive technique for improving the implant-bone interface that can be applied to titanium and titanium alloys. This technique produces a surface with microporous morphology and an oxide layer enriched with calcium and phosphorus. The aim of the present study was to investigate the biological response in vitro using primary human osteoblasts as a cellular model and the osteogenic primary response in vivo within a short experimental time frame (2 and 4 weeks) in an animal model (rabbit). Responses were assessed by comparing the new electrochemical biomimetic treatments to an acid-etching treatment as control. The in vitro biological response was characterized by cell morphology, adhesion, proliferation activity and cell metabolic activity. A complete assessment of osteogenic activity in vivo was achieved by estimating static and dynamic histomorphometric parameters at several time points within the considered time frame. The in vitro study showed enhanced osteoblast adhesion and higher metabolic activity for the ASD-treated surfaces during the first days after seeding compared to the control titanium. For the ASD surfaces, the histomorphometry indicated a higher mineral apposition rate within 2 weeks and a more extended bone activation within the first week after surgery, leading to more extensive bone-implant contact after 2 weeks. In conclusion, the ASD surface treatments enhanced the biological response in vitro, promoting an early osteoblast adhesion, and the osteointegrative properties in vivo, accelerating the primary osteogenic response.


Assuntos
Galvanoplastia/métodos , Fraturas do Fêmur/patologia , Fraturas do Fêmur/cirurgia , Osteoblastos/fisiologia , Osteoblastos/transplante , Osteogênese/fisiologia , Engenharia Tecidual/métodos , Titânio/química , Animais , Pré-Escolar , Cristalização/métodos , Humanos , Teste de Materiais , Osteoblastos/patologia , Coelhos , Resultado do Tratamento
18.
Monaldi Arch Chest Dis ; 67(3): 135-41, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18018752

RESUMO

BACKGROUND AND AIM: Asthma that begins around the time of menopause is frequently characterised by marked clinical severity and poor response to treatment. We sought to assess the clinical characteristics, bronchial responsiveness, perception of induced bronchoconstriction and airway inflammation in women with menopausal asthma, as compared to women of a similar age with pre-existing asthma. METHODS: Nine women with pre-existing asthma were selected for clinical severity (symptoms, lung function and medication requirements) similar to that in 11 women with menopausal asthma. Anti-asthmatic treatment in all of the study patients included high dose inhaled (with or without oral) corticosteroids. RESULTS: The women with menopausal asthma demonstrated less atopy, more chronic recurrent sinusitis, similar airway responsiveness, and similar perception of induced bronchoconstriction, but a significantly higher sputum eosinophil count (19.5 +/- 10.8 versus 3.3 +/- 4.3%; p < 0.001) and a higher severe exacerbation rate during the 1-year follow-up period (5.09 +/- 4.85 versus 0.78 +/- 0.97; p < 0.05). Sputum eosinophil count and severe asthma exacerbation rate correlated well in both groups considered as a whole (r = 0.65; p < 0.005). CONCLUSION: The eosinophilic airway inflammation present in women with menopausal asthma is poorly responsive to anti-inflammatory treatment with corticosteroids and predisposes to frequent severe exacerbations. Airway inflammation should be monitored in women with menopausal asthma.


Assuntos
Idade de Início , Antiasmáticos/administração & dosagem , Asma/fisiopatologia , Nível de Saúde , Menopausa/fisiologia , Adulto , Asma/etiologia , Feminino , Humanos , Pessoa de Meia-Idade , Testes de Função Respiratória , Índice de Gravidade de Doença
19.
Phys Rev Lett ; 97(14): 144509, 2006 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-17155263

RESUMO

The persistence of ratchet effects, i.e., nonzero mass flux under a zero-mean time-dependent drive, when many-body interactions are present, is studied via molecular dynamics (MD) simulations of a simple liquid flowing in an asymmetric nanopore. The results show that (i) ratchet effects persist under many-body density correlations induced by the forcing; (ii) two distinct linear responses (flux proportional to the drive amplitude) appear under strong loads. One regime has the same conductivity of linear response theory up to a forcing of about 10 kT, while the second displays a smaller conductivity, the difference in responses is due to geometric effects alone. (iii) Langevin simulations based on a naive mapping of the many-body equilibrium bulk diffusivity, D, onto the damping rate, gamma are also found to yield two distinct linear responses. However, in both regimes, the flux is significantly smaller than the one of MD simulations.


Assuntos
Modelos Químicos , Nanoestruturas/química , Simulação por Computador , Entropia , Canais Iônicos/química , Termodinâmica
20.
Monaldi Arch Chest Dis ; 65(1): 52-5, 2006 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-16700196

RESUMO

A number of predisposing factors (obesity, nasal obstruction, adenoidal hypertrophy, macroglossia, etc) have been related to obstructive sleep apnea syndrome (OSAS). In addition hypothyroidism and large goitres have been reported to be associated to OSAS, but this association has not been adequately studied. We describe an obese patient with euthyroid goitre associated with OSAS. The patient showed a body mass index (BMI) of 47 and a large neck with a circumference of 60 cm. The flow-volume curve demonstrated an expiratory plateau suggesting an intrathoracic upper airway obstruction. Arterial blood gas analysis results were: pH 7.39; PCO2 54.2 mmHg; P O2 47 mmHg. Nocturnal polisomnography showed an apnea/hypopnea index (AHI) of 31 episodes/hour. Upper airway collapse was overcome by a nasal continuous positive airway pressure (nCPAP) of 14 cmH2O. Weight loss obtained by a hypocaloric diet was not accompanied by any OSAS improvement. After thyroidectomy, a nCPAP of 4 cmH2O was sufficient to prevent upper airway closure. Discontinuation of nCPAP treatment for 4 consecutive nights did not determine worsening of sleep apnea symptoms, nor a worsening of overnight oxymetry. A new polysomnography carried out after 4 nights off nCPAP showed an AHI of 33 episodes/hour. OSAS should be suspected in patients with large goitres. Decisions regarding discontinuation of nCPAP treatment after thyroidectomy should be based on polisomnographic results.


Assuntos
Bócio Nodular/complicações , Apneia Obstrutiva do Sono/etiologia , Idoso , Índice de Massa Corporal , Pressão Positiva Contínua nas Vias Aéreas , Bócio Nodular/cirurgia , Humanos , Masculino , Obesidade/complicações , Polissonografia , Testes de Função Respiratória , Apneia Obstrutiva do Sono/diagnóstico , Apneia Obstrutiva do Sono/terapia , Tireoidectomia , Redução de Peso
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