107 research outputs found

    An experimental test of the Jarzynski equality in a mechanical experiment

    Get PDF
    We have experimentally checked the Jarzynski equality and the Crooks relation on the thermal fluctuations of a macroscopic mechanical oscillator in contact with a heat reservoir. We found that, independently of the time scale and amplitude of the driving force, both relations are satisfied. These results give credit, at least in the case of Gaussian fluctuations, to the use of these relations in biological and chemical systems to estimate the free energy difference between two equilibrium states. An alternative method to estimate of the free nergy difference in isothermal process is proposed too.Comment: submitted to Europhysics Letter

    Masseteric-facial nerve neurorrhaphy: results of a case series

    Get PDF
    OBJECTIVE: Facial palsy is a well-known functional and esthetic problem that bothers most patients and affects their social relationships. When the time between the onset of paralysis and patient presentation is less than 18 months and the proximal stump of the injured facial nerve is not available, another nerve must be anastomosed to the facial nerve to reactivate its function. The masseteric nerve has recently gained popularity over the classic hypoglossus nerve as a new motor source because of its lower associated morbidity rate and the relative ease with which the patient can activate it. The aim of this work was to evaluate the effectiveness of masseteric-facial nerve neurorrhaphy for early facial reanimation. METHODS: Thirty-four consecutive patients (21 females, 13 males) with early unilateral facial paralysis underwent masseteric-facial nerve neurorrhaphy in which an interpositional nerve graft of the great auricular or sural nerve was placed. The time between the onset of paralysis and surgery ranged from 2 to 18 months (mean 13.3 months). Electromyography revealed mimetic muscle fibrillations in all the patients. Before surgery, all patients had House-Brackmann Grade VI facial nerve dysfunction. Twelve months after the onset of postoperative facial nerve reactivation, each patient underwent a clinical examination using the modified House-Brackmann grading scale as a guide. RESULTS: Overall, 91.2% of the patients experienced facial nerve function reactivation. Facial recovery began within 2-12 months (mean 6.3 months) with the restoration of facial symmetry at rest. According to the modified House-Brackmann grading scale, 5.9% of the patients had Grade I function, 61.8% Grade II, 20.6% Grade III, 2.9% Grade V, and 8.8% Grade VI. The morbidity rate was low; none of the patients could feel the loss of masseteric nerve function. There were only a few complications, including 1 case of postoperative bleeding (2.9%) and 2 local infections (5.9%), and a few patients complained about partial loss of sensitivity of the earlobe or a small area of the ankle and foot, depending on whether great auricular or sural nerves were harvested. CONCLUSIONS: The surgical technique described here seems to be efficient for the early treatment of facial paralysis and results in very little morbidity

    Long-term disease-free survival in surgically-resected oral tongue cancer: a 10-year retrospective study

    Get PDF
    Sopravvivenza libera da malattia a lungo termine nel tumore della lingua mobile operato: studio retrospettivo a 10 anni.PLAIN-LANGUAGE-SUMMARY: Early and loco-regionally advanced oral tongue squamous cell carcinoma (OTSCC) can be treated by surgery alone or followed by adjuvant radiotherapy or chemoradiotherapy. Nevertheless, up to 40% of patients develop tumour relapse. The aim of our study is to investigate the clinical and pathological features associated with reduced disease-free survival (DFS) in a cohort of surgically-resected OTSCC patients. One hundred and six patients surgically resected for OTSCC were retrospectively identified from clinical records. DFS was calculated according to the Kaplan\u2013Meier method and differences between variables were assessed with Log-Rank test. A multivariable Cox regression model was used to analyse the impact of different prognostic factors on DFS. After a median of follow-up of 8.9 years, 22 events, including 11 deaths, were observed. Overall, the 5-year DFS-rate was 87.4%. The presence of extra-nodal extension (p = 0.023) and perineural invasion (p = 0.003) were significantly correlated with shorter DFS (in univariate analysis). In multivariable analysis, extra-nodal extension and perineural invasion confirmed their role as independent prognostic factors associated with an increased risk of disease recurrence [hazard ratio (HR) 2.87, 95% CI 1.11-7.42, p = 0.03; HR 3.85, 95% CI 1.49-9.96, p = 0.006, respectively]. p16 and p53 expressions in tumour cells were detected in 12% (n = 9) and 46% (n = 40) of cases, respectively. No differences in DFS were observed between p16+ and p16- (p = 0.125) and between p53+ and p53- tumours (p = 0.213). In conclusion, radical surgery, eventually followed by adjuvant radiotherapy or chemo-radiotherapy, can achieve high cure rates in OTSCC. After long-term follow-up, perineural invasion and extra-nodal extension confirmed their role as prognostic factors associated with reduced DFS in OTSCC patients

    Congenital hypothyroidism with eutopic thyroid gland : analysis of clinical and biochemical features at diagnosis and after re-evaluation

    Get PDF
    Context: In recent years changes in screening strategies for congenital hypothyroidism (CH) led to an increased detection of mild forms of CH, associated with eutopic thyroid gland. Objectives: We aimed to determine the clinical evolution of CH with eutopic thyroid gland and to find out prognostic factors at diagnosis and follow-up. Patients and Methods: We retrospectively analyzed agroup of84 children withCH andeutopic thyroid gland treated at our institution. They all underwent clinical re-evaluation after the age of 3, based on thyroid function testing after L-thyroxine therapy withdrawal, thyroid ultrasonography, and 123I scintigraphy with perchlorate discharge test. Genetic analysis was performed in selected cases. Results: At re-evaluation, 34.5% of patients showed permanent hypothyroidism and needed L-thyroxine reintroduction, 27.4% had persistent hyperthyrotropinemia (TSH5-10mU/L), and 38.1% had transient hypothyroidism. Major risk factors for permanent CH were prematurity, first-degree familial history of goiter/nodules, thyroid hypoplasia at diagnosis, and high L-thyroxine requirements at follow-up. Iodine organification defects were found in 29.7% of patients, 30% of whom harbored DUOX2 mutations. TSH receptor gene mutations were found in 8.7% of patients with persistent thyroid dysfunction and negative perchlorate discharge test. Conclusions: Only one-third of patients with CH and eutopic thyroid gland needed to continue L-thyroxine therapy after re-evaluation. A frequent finding was the persistence of mild hyperthy-rotropinemia. The evolution of CH remains difficult to predict, although different clinical features might suggest different outcomes. Mutations in the genes commonly linked to mild forms of CH were documented in a minority of cases. Copyrigh

    Multinational firms from emerging countries and traditional IB theories: Some evidences from acquisitions in advanced countries

    No full text
    This paper provides a dynamic view of the international expansion of emerging multinational companies (EMNCs), by combining the framework of country-specific advantages (CSAs) and firm-specific advantages (FSAs) with an analysis of the value chain disaggregation. We study 417 acquisitions in Western countries, made by EMNCs from Brazil, Russia, India and China (BRICs) between 2000 and 2007. The internationalisation strategies of EMNCs are disentangled by analysing three dimensions: home country characteristics, technology intensity of target and acquirer industries, and industrial relatedness between target and acquirer firms. Results show that horizontal and vertical acquisitions are driven by strong CSAs based on national endowments and aim at upgrading the weak FSAs of EMNCs; conglomerate investments are driven by CSAs that rely on the institutional context of the BRICs, and related investments are used to implement diversification strategies without connections to CSAs. EMNCs have evolved from performing low value added activities to high value added upstream and downstream activities, which facilitate the future empowerment of FSAs
    • …
    corecore