Fatigue Behaviour of High-Performance Green Epoxy Biocomposite Laminates Reinforced by Optimized Long Sisal Fibers.

In recent decades, in order to replace traditional synthetic polymer composites, engineering research has focused on the development of new alternatives such as green biocomposites constituted by an eco-sustainable matrix reinforced by natural fibers. Such innovative biocomposites are divided into two different typologies: random short fiber biocomposites characterized by low mechanical strength, used for non-structural applications such as covering panels, etc., and high-performance biocomposites reinforced by long fibers that can be used for semi-structural and structural applications by replacing traditional materials such as metal (carbon steel and aluminum) or synthetic composites such as fiberglass. The present research work focuses on the high-performance biocomposites reinforced by optimized sisal fibers. In detail, in order to contribute to the extension of their application under fatigue loading, a systematic experimental fatigue test campaign has been accomplished by considering four different lay-up configurations (unidirectional, cross-ply, angle-ply and quasi-isotropic) with volume fraction Vf = 70%. The results analysis found that such laminates exhibit good fatigue performance, with fatigue ratios close to 0.5 for unidirectional and angle-ply (±7.5°) laminates. However, by passing from isotropic to unidirectional lay-up, the fatigue strength increases significantly by about four times; higher increases are revealed in terms of fatigue life. In terms of damage, it has been observed that, thanks to the high quality of the proposed laminates, in any case, the fatigue failure involves the fiber failure, although secondary debonding and delamination can occur, especially in orthotropic and cross-ply lay-up. The comparison with classical synthetic composites and other similar biocomposite has shown that in terms of fatigue ratio, the examined biocomposites exhibit performance comparable with the biocomposites reinforced by the more expensive flax and with common fiberglass. Finally, appropriate models, that can be advantageously used at the design stage, have also been proposed to predict the fatigue behavior of the laminates analyzed.

Intravenous IgG: biological modulating molecules.

Intravenous IgG has been adopted as treatment for various immune-related diseases, including immune thrombocytopenic purpura, autoimmune neuropathies, systemic lupus erythematosus, Guillain-Barré syndrome, myasthenia gravis, Kawasaki disease, skin blistering diseases. The intravenous administration of exogenously pooled human immunoglobulin was originally licensed as antibody replacement therapy in patients with primary immunodeficiencies, but in the last thirty years, despite a current lack of institutional approval, off-label IVIgG treatment of a consistent number of disorders has shown to be a useful approach with good clinical results. The mechanism of action of IVIgG is complex and is not fully understood. The current understanding and development in the immune modulant action of IVIgG has three basic mechanisms: 1) F(ab')2 mediated actions; 2) interaction of IgGFc molecule with Fc receptors (FcgammaR); 3) actions mediated by complement fractions binding within the Fc molecular structure. The mode of action of IVIgG involves expression and function of Fc receptors, idiotype network, complement and cytokine network, T and B cell differentiation, modulation of antigen-presenting cells (APC). The therapeutic action of IVIgG is also related to natural antibodies in maintaining immune homeostasis. In addition, IVIgG interaction through V regions with complementary V regions of antibodies may provide a rational basis for selection of various immune repertoires. Since there is a significant gap between the institutional approval and the use of IVIgG in various clinical conditions, for which there is no adequate testing or for which a small number of records does not allow a rigorous statistical approach, several public and private institutions (mostly insurance companies) and research centres have developed guidelines for evaluating a rational and deontological approach in various pathological situations where IVIgG is used. Mathematical models based on non-linear differential equations may represent another potentially useful system to better understand an IVIgG targeted use in individual subjects.

Will a second prophylactic treatment with a higher dosage of the same antidepressant either prevent or delay new depressive episodes?

Fifty-seven highly recurrent unipolar patients, excluded from previous long-term studies with selective serotonin reuptake inhibitors (SSRIs) after they experienced a new recurrence, were acutely treated with the full dosage of the SSRIs they were on. Fifty-one of them (89.5%) had a sustained response and entered into the 4-month continuation therapy. During this phase, no relapse was observed. At the end of it, all patients gave their written informed consent to be enrolled in a 24-month long-term therapy, maintaining the same treatment dosage of fluvoxamine 300 mg/day, sertraline 150 mg/day, or paroxetine 40 mg/day. At the end of the study, 28 out of the 51 outpatients (54.9%) showed a further recurrence. Nevertheless, second recurrences observed during this second maintenance therapy were less severe than first recurrences, decreasing from 25.1+/-3.4 to 21.6+/-3.3 (P<0.0001), respectively. Considering the clinical characteristics of patients, we found that a high number of prior depressive episodes and an early age at onset of illness may predict a bad outcome. Moreover, patients with a longer duration of euthymia during a first maintenance period are less likely to have a new episode of depression.

Rupture of the pulmonary alveoli during general anesthesia.

The rupture of pulmonary alveoli during the induction of general anesthesia is a significant complication of general anesthesia that has been seldom reported in our literature. This article documents this occurrence in a patient scheduled for elective orthognathic surgery. The diagnosis and treatment are discussed.

Dual diagnosis: developmental disability complicated by mental illness.

When mental retardation is complicated by mental illness, the clinical result is "dual diagnosis." Though recognized as such only since the 1970s, these patients have long been the subset of the developmentally disabled most resistant to integration into the community. The maladaptive behavior or mental illness often prevents training for the retardation or other developmental disability. Because these patients are no longer placed in the back wards of state institutions, the modern expectation is that even this most difficult group can be influenced by positive behavior support directed by a psychologist and medication treatment programs prescribed by a psychiatrist. In addition, program specialists structure the work, play, and learning environment of the patients. These activities, living conditions, and peer relationships will form a dynamic interaction with the behavior therapy and the medication. The challenge of adapting to this interaction is met by an interdisciplinary team. Subject to bizarre behavior and difficult to diagnose and treat, patients with both mental retardation and mental illness are best directed to providers trained for these patients.

[Sciatica: an open problem]. / Sciatalgia: problema aperto.

The Authors believe it erroneous to consider disc herniation as the only pathology responsible of sciatalgia. They emphasize the importance of proper diagnostic investigation prior to any operative intervention.