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Lumbosacral neuroforaminal stenosis (LNFS) is a common cause of sciatica in people and large breed dogs. Nerve root entrapment goes with significant swelling of the tissue, which winds-up the pressure on the root in a vicious circle. Thereby, compression of small vessels is supposed to increase vascular[for full text, please go to the a.m. URL], Joint-Meeting of the German Society for Neuropathology and Neuroanatomy (DGNN) and the Scandinavian Neuropathological Society (SNS)

Nickel–Titanium (NiTi) shape memory alloys subjected to cyclic loading exhibit reversible temperature changes whose modulation is correlated with the applied load. This reveals the presence of reversible thermomechanical heat sources activated by the applied stresses. One such source is the elastocaloric effect, accounting for the latent heat of Austenite–Martensite phase transformation. It is, however, observed that when the amplitude of cyclic loads is not sufficient to activate or further propagate this phase transformation, the material still exhibits a strong cyclic temperature modulation. The present work investigates the thermomechanical behaviour of NiTi under such low-amplitude cyclic loading. This is carried out by analysing the frequency domain content of temperature sampled over a time window. The amplitude and phase of the most significant harmonics are obtained and compared with the theoretical predictions from the first and second-order theories of the Thermoelastic Effect, this being the typical reversible thermomechanical coupling prevailing under elastic straining. A thin strip of NiTi, exhibiting a fully superelastic behaviour at room temperature, was investigated under low-stress amplitude tensile fatigue cycling. Full-field strain and temperature distributions were obtained by means of Digital Image Correlation and IR Thermography. The work shows that the full field maps of amplitude and phase of the first three significant temperature harmonics carry out many qualitative information about the stress and structural state of the material. It is, though, found that the second-order theory of the Thermoelastic Effect is not fully capable of justifying some of the features of the harmonic response, and further work on the specific nature of thermomechanical heat sources is required for a more quantitative interpretation.

Background: The intranasal (IN) route for rapid drug administration in patients with brain disorders, including status epilepticus, has been investigated. Status epilepticus is an emergency, and the IN route offers a valuable alternative to other routes, especially when these fail. Objectives: To compare IN versus IV midazolam (MDZ) at the same dosage (0.2 mg/kg) for controlling status epilepticus in dogs. Animals Client-owned dogs (n = 44) with idiopathic epilepsy, structural epilepsy, or epilepsy of unknown origin manifesting as status epilepticus. Methods: Randomized parallel group clinical trial. Patients were randomly allocated to the IN-MDZ (n = 21) or IV-MDZ (n = 23) group. Number of successfully treated cases (defined as seizure cessation within 5 minutes and lasting for >= 10 minutes), seizure cessation time, and adverse effects were recorded. Comparisons were performed using the Fisher's exact and Wilcoxon rank sum tests with statistical significance set at alpha < .05. Results: IN-MDZ and IV-MDZ successfully stopped status epilepticus in 76% and 61% of cases, respectively (P = .34). The median seizure cessation time was 33 and 64 seconds for IN-MDZ and IV-MDZ, respectively (P = .63). When the time to place an IV catheter was taken into account, IN-MDZ (100 seconds) was superior (P = .04) to IV-MDZ (270 seconds). Sedation and ataxia were seen in 88% and 79% of the dogs treated with IN-MDZ and IV-MDZ, respectively. Conclusions and Clinical Importance: Both routes are quick, safe, and effective for controlling status epilepticus. However, the IN route demonstrated superiority when the time needed to place an IV catheter was taken into account.

Fatigue damage onset involves a transformation of mechanical energy. This is in part spent into work of plastic deformation and fracture and in part transformed into heat. Therefore, different thermomechanical heat sources are activated during a fatigue loading cycle, resulting in a temperature modulation that can be characterized by its frequency content. Several studies have monitored the temperature on samples undergoing high-cycle fatigue, measuring specific thermomechanical metrics which could serve as indicators of damage evolution. The present work evaluates the harmonic content of temperature, to investigate its correlation with the material dissipation. The harmonic terms investigated are the amplitude and phase of temperature at the loading frequency (First Harmonic) and at twice the loading frequency (Second Harmonic). The paper reviews the mechanisms linking the evolution of heat dissipation to changes in these four parameters. The theoretical analysis is supported by an experimental campaign carried out on C45 steel tensile specimen subject to R=−1 and R=0.1 loading ratios. The harmonic metrics are evaluated analyzing both their spatially averaged value and their spatial dispersion, to check for the formation of localized heat dissipation zones in early fatigue life. The study shows that the phase of the Second Harmonic signal has a peculiar bimodal distribution that can be correlated to either a thermoelastic or dissipative prevailing effect. This behavior evolves towards a unimodal dissipative behavior when the load amplitude is increased, thus proposing the Second Harmonic phase parameter as an effective indicator for monitoring internal intrinsic dissipation in the material.

The mode I fracture parameters for an orthotropic body are directly calculated from full-field deformation measurements provided by Digital Image Correlation (DIC). Three complementary and direct approaches are evaluated and compared: (i) the determination of the Stress Intensity Factor (SIF) by fitting the displacement field using the analytical expression proposed by Lekhnitskii; (ii) the determination of the J-Integral by using the Energy Domain Integral (EDI) formulation on the raw DIC data; and (iii) the calculation of the J-Integral using the EDI approach on the displacement data fitted using Lekhnitskii’s formulation. A comparative experimental study is performed by testing an IM7/8552 cross-ply laminate, and the effect of different parameters is analysed and discussed. The outcomes of this work show that, if an accurate choice of the parameters is performed, the different approaches lead to the same results.

A low-cost Thermoelastic Stress Analysis (TSA) experimental setup is proposed which uses an ordinary micro-bolometer and in-house developed signal processing scripts. The setup is evaluated by analysing the thermoelastic signal from a tensile and a SENT specimen made of stainless steel AISI 304L, and the bolometer performances are compared with those of a state of the art photon detector. Signal processing is based on off-line cross-correlation, using a self-reference signal which is retrieved from the acquired thermal data. Procedures are in particular developed to recognise, quantify and correct errors due to spectral leakage and loss of streamed frames. The thermoelastic signal amplitude/phase, the thermoelastic constant and the Mode I Stress Intensity Factor (SIF) from the bolometer and photonic cameras are evaluated considering the influence of loading frequency, sampling frequency, detector array sub-windowing and acquisition interval duration. A camera-specific linear calibration procedure is applied to correct the thermoelastic signal obtained with the bolometer. The procedure is extended to correct also SIF values, finding a good match with the SIFs obtained by the photon detector. An automatic iterative algorithm, based on the least square fitting of Williams’ series functions, is proposed to identify the crack tip position. An estimation of processing times of the developed signal processing scripts has been carried out, finding that a full crack characterisation (TSA maps, crack tip position, SIF) can be performed with a data acquisition time of 10-20 s, a post-processing time of less than 2 s and an overall hardware cost under 10 k€.

Ottimizzazione della terapia antiretrovirale e clearance spontanea di infezione cronica da HCV

AIDS presenter con situazione virologica-immunologica stabile dopo venti anni di follow-up, nonostante la mancata aderenza alle terapie antiretrovirali ed antimicrobiche