P14.86 Predictive value of MGMT promoter (pMGMT) methylation status on pseudoprogression (PsP) and survival analysis in Glioblastoma (GBM) patients: a retrospective single institutional analysis

BACKGROUND Glioblastoma is the most common and aggressive primary brain tumor. Conventional therapies, such as maximal extension of surgery followed by radiotherapy (RT) and chemotherapy with Temozolomide (TMZ) have not resulted in major improvements in terms of patients’ outcome, overall survival (OS) still remaining poor. In this context, radiological response assessment after radiotherapy remains challenging due to the potential effect of radionecrosis, often mimicking tumor progression. Differentiation between PsP and true progression is required to avoid further unnecessary surgeries, or the premature discontinuation of TMZ. It is known that pMGMT methylated patients respond better to chemotherapy than unmethylated counterpart, so, tumor cells necrosis can be enhanced in this setting. The aim of the study is to observe the correlation between pMGMT methylation status with the incidence of PsP in GBM patients at the first radiological evaluation after RT. MATERIALS AND METHODS Patients with histologically diagnosis of GBM from 2017 to 2021 and availability of pMGMT methylation status were enrolled. PsP was radiologically defined at first brain MRI after RT in case of increasing size of the enhancing component and of peritumoral oedema that remain stable or decrease after antioedema therapy, such as a clinical improvement was observed. RESULTS We analysed 55 GBM patients, 35 (64%) displayed pMGMT methylation whereas 20 (36%) resulted pMGMT unmethylated. PsP was evident in 29 patients (53%), all of them showed methylation of pMGMT. In our analysis, none of pMGMT unmethylated patients experienced PsP. Regarding survival outcome for pMGMT methylated patients, our analysis shows a mPFS of 8.7 (95% CI: 5–10) months versus 9.3 (95%CI: 4.6–12.3) months in methylated and unmethylated respectively (p=0.87). CONCLUSIONS Methylation status of pMGMT showed to be predictor of PsP in GBM patients. If validated, this information could be very useful to guide clinicians in differentiating PsP from true progression. To date, our survival analysis regarding PFS showed no statistical difference among methylated patients with respect to the presence or absence of PsP. Thus, PsP seems not to be a marker of responsiveness to common treatment. Further data are needed to validate our results.

Localization of maximal stresses in axisymmetric waves in elastic rods for positive Poisson’s ratio

Рассмотрены максимальные напряжения в осесимметричных волнах в упругих стержнях для положительных значений коэффициента Пуассона. Обнаружена особая длина волны, для которой имеет место наибольшее значение максимального растяжения на оси по отношению к максимальному растяжению на поверхности. Показано, что и особая длина волна, и наибольшее значение отношений растяжений не зависят от коэффициента Пуассона. The maximum stresses in axisymmetric waves in elastic rods for positive values of the Poisson’s ratio are considered. A special wavelength has been found for which the ratio of axial maximal extension to surface maximal extension has the largest value. It is shown that both the special wavelength and the largest value of the extensions ratio are independent of the Poisson’s ratio.

NUMERICAL ESTIMATION OF SHAPED CHARGES EFFICIENCY

The paper shows the estimations of maximal penetration depths of shaped charge jets in a steel armour as a function of stand-off distance to the liner base. The data – in-stantaneous coordinates of positions, masses, and velocities of jet elements were received as results of numerical calculations for selected examples of designs of shaped charges. It was shown that the crater’s depth is a function of acceptable maximal extension of jet elements and their minimal velocity. The results were compared with experimental data.

Two Infinite Sequences of Pre-Maximal Extensions of the Relevant Logic E

The only maximal extension of the logic of relevant entailment E is the classical logic CL. A logic L ⊆ [E,CL] called pre-maximal if and only if L is a coatom in the interval [E,CL]. We present two denumerable infinite sequences of premaximal extensions of the logic E. Note that for the relevant logic R there exist exactly three pre-maximal logics, i.e. coatoms in the interval [R,CL].

A theory on the spreading of impacting droplets

Here we provide a self-consistent analytical solution describing the unsteady flow in the slender thin film which is expelled radially outwards when a drop hits a dry solid wall. Thanks to the fact that the fluxes of mass and momentum entering into the toroidal rim bordering the expanding liquid sheet are calculated analytically, we show here that our theoretical results closely follow the measured time-varying position of the rim with independence of the wetting properties of the substrate. The particularization of the equations describing the rim dynamics at the instant the drop reaches its maximal extension which, in analogy with the case of Savart sheets, is characterized by a value of the local Weber number equal to one, provides an algebraic equation for the maximum spreading radius also in excellent agreement with experiments. The self-consistent theory presented here, which does not make use of energetic arguments to predict the maximum spreading diameter of impacting drops, provides us with the time evolution of the thickness and of the velocity of the rim bordering the expanding sheet. This information is crucial in the calculation of the diameters and of the velocities of the droplets ejected radially outwards for drop impact velocities above the splashing threshold.

Evaluation of Mechanical Properties of the Two PVC Conveyor Belts

Conveyor belts with woven plastic belts, aimed for general applications, are very economical transporting means for longer distances. During the operation, the conveyor belts are subjected to various mechanical loadings. The consequences of those loadings are increased stretching of the belt and change of its tensile strength, which negatively affect the proper functioning of the transporter. To avoid the irregularities in the conveyor belt's operation, the tensile properties of the two plastic woven belts were tested (maximal force, maximal extension, breaking force and extension at break). In that way the conditions of the two belts were established. Based on performed experiments the belt that is more suitable for application in the transporter was defined.

Effect of Gender, Toe Extension Position, and Plantar Fasciitis on Plantar Fascia Thickness

Background: Ultrasound is a widely used diagnostic tool for patients with plantar fasciitis. However, the lack of standardization during the measurement for plantar fascia thickness has made it challenging to understand the etiology of plantar fasciitis, as well as identify risk factors, such as gender. The purpose of this study was to investigate gender differences regarding plantar fascia thickness while controlling for metatarsophalangeal (MTP) joint position in the healthy and those with unilateral plantar fasciitis. Methods: Forty participants (20 with unilateral plantar fasciitis and 20 controls) with plantar fascia thickness (mean age, 44.8 ± 12.2 years) participated in this study. The majority were females (n = 26, 65%). Plantar fascia thickness was measured via ultrasound 3 times at 3 different MTP joint positions: (1) at rest, (2) at 30 degrees of extension, and (3) at maximal extension. Results: When comparing gender differences, the males in the plantar fasciitis group had a significantly thicker plantar fascia than the females ( P = .048, η2 = 2.35). However, no significant differences were observed between healthy males and females. The males with unilateral plantar fasciitis also had significantly thicker asymptomatic plantar fasciae collectively compared with controls ( P < .05), whereas females with unilateral plantar fasciitis had a similar but not significant change. Conclusion: It appears that healthy males and females have similar plantar fascia thickness. However, as plantar fasciitis develops, males tend to develop thicker plantar fasciae than their female counterparts, which could have future treatment implications. Level of Evidence: Level III, case-control comparative study.