Nichtlokale Korrelation in kaonischen Systemen

Die Nichtlokalität von Quantensystemen steht im Mittelpunkt der heutigen Physik. Sie ergibt sich direkt aus dem Superpositionsprinzip. Sie ist eine Eigenschaft, die aus dem Wellencharakter von Quantenobjekten folgt. Die Nichtlokalität gibt uns Physikern noch immer einige Rätsel auf. So hat man durch statistische Messungen mit Hilfe der Bellschen Ungleichungen nachweisen können, dass die Nichtlokalität nicht etwa ein scheinbarer Effekt ist, der nur auf Unkenntnis der wahren Verhältnisse zurückzuführen ist, sondern zu realen Effekten, wie z.B. der Quantenteleportation, führt. Diese Arbeit untersucht die nichtlokalen Korrelationen in kaonischen Systemen in Lichte der zwei Gebiete, nämlich der Teilchen Physik und der Grundlagen der Quantenmechanik. Der erste Teil bringt eine Einführung in die neutralen Kaonen. Die Verletzung der CP- Symmetrie (charge, parity) ist für das Verständnis der Elementarteilchenphysik von entscheidender Bedeutung, insbesondere zur Erklärung des Materieüberschusses bei der Teilchen-Antiteilchen Erzeugung im frühen Universium. Durch das Experiment von Christensen, Cronin und Fitch (1964) [1] wissen wir, dass beim Zerfall der neutralen Kaonen die CP- Symmetrie verletzt wird und dies bedeutet, dass auf Grund des CPT Theorems auch die Zeitumkehr T verletzt ist. Weiters wird im ersten Teil auch der Regenerationseffekt der Kaonen abgeleitet. Im zweiten Teil werden die verschränkten Quantensysteme besprochen. Die Standard- Interpretation der Quantenmechanik geht davon aus, dass die quantenmechanische Beschreibung eines Systems im allgemeinen nur statistische Aussagen über einzelne Messungen ermöglicht. Im Jahre 1935 konstuierten Einstein, Podolsky und Rosen [2] unter gewissen Annahmen (insbesondere Lokalität) ein Beispiel, das die Existenz verborgener lokaler Parameter zeigen sollte; dieses Beispiel wird als EPR Paradoxon bezeichnet. 30 Jahre später zeigte Bell [3] in seiner berühmten Ungleichung für bestimmte Messwerte, dass die Annahmen des EPR Paradoxons im Widerspruch zur Quantenmechanik stehen. Diese Ungleichung wurde 1969 von Clauser, Horne, Shimony, und Holt (CHSH) [4] für reale Experimente angepasst. Neben der CHSH-Ungleichung gibt es zahlreiche weitere Ansätze zur Verletzung der Bellschen Ungleichung. Im folgenden werden die Ungleichungen für Zweiteilchensysteme vorgestellt; dies sind CH [5] (Clauser,Horne), Wigner [6], CHSH [4] und Eberhard [7] Ungleichungen. Der dritte Teil bringt die Verwendung der Bell Ungleichungen für neutrale Kaonensysteme. Wir haben die Bell Ungleichungen mit Regenerator durch den Vergleich zwischen dem lokalen Realismus und Quantenmechanik getestet [8]. Damit haben wir zwei spezielle Ungleichungen - CH und Eberhard - näher diskutiert [9, 10, 11]. Zum Schluss wurde ein Loophole für diese speziellen Ungleichungen überprüft [9]. Hatice Tataroglu, Wien 200

Re-irradiation with stereotactic radiotherapy for recurrent high grade glial tumors

Background: Despite the radical treatments applied, recurrence is encountered in the majority of high-grade gliomas (HGG). There is no standard treatment when recurrence is detected, but stereotactic radiotherapy (SRT) is a preferable alternative. The aim of this retrospective study is to evaluate the efficacy of SRT for recurrent HGG, and to investigate the factors that affect survival. Materials and methods: From 2013 to 2021, a total of 59 patients with 64 lesions were re-irradiated in a single center with the CyberKnife Robotic Radiosurgery System. The primary endpoints of the study were overall survival (OS), progression free survival (PFS) and local control rates (LCR). Results: The median time to first recurrence was 13 (4–85) months. SRT was performed as a median prescription dose of 30 Gy (range 15–30), with a median of 5 fractions (1–5). The median follow-up time was 4 months (range 1–57). The median OS was 8 (95% CI: 4.66-11.33) months. Age, grade 3, tumor size were associated with better survival. The median PFS was 5 [95% confidence interval (CI): 3.39–6.60] months. Age, grade 3 and time to recurrence > 9 months were associated with improved PFS. Grade 3 gliomas (p = 0.027), size of tumor < 2 cm (p = 0.008) remained independent prognostic factors for OS in multivariate analysis. Conclusion: SRT is a viable treatment modality with significant survival contribution. Since it may have a favorable prognostic effect on survival in patients with tumor size < 2 cm, we recommend early diagnosis of recurrence and a decision to re-irradiate a smaller tumor during follow-up.

Stereotactic radiotherapy in acoustic neuroma cases: Tumor control and clinical results

Since acoustic neuromas (AN) are slow-growing tumors, they frequently reduce patients' quality of life by compressing adjacent nerves. After evaluating various factors, the most appropriate treatment for the patient is preferred among follow-up, surgery, or radiotherapy. Surgery and radiotherapy have been shown to have comparable results in AN. Stereotactic radiotherapy (SRT) has long emerged as a viable option for treating intracranial tumors. Thus, it was aimed to determine the local control rate (LCR), and treatment failure and to evaluate the hearing level and facial nerve symptoms in AN treated with SRT. Forty-five patients were treated consecutively with CyberKnife-SRT between January 2014 and December 2021. Tumors were anatomically classified according to Koos grade; patients presenting with hearing impairment were graded according to the Gardner-Robertson (GR) scale and patients' expressions. Loss of function in the facial nerve was also evaluated according to the House-Brackman scale. SRT was applied to 24 patients with 12 Gy/1 fx, 18 with 18 Gy/3 fx, and 3 with 25 Gy/5 fx. At a median follow-up of 24 months (2-73), progression was detected in 4 (8.9%) patients. None required additional intervention, and no treatment failure was observed (0%). Tumor control was achieved in 91.1% of the patients; 2-y and 5-y LCR were 91.2% and 79.8%. It was observed that 3 (30%) out of 10 patients who had serviceable hearing according to the GR scale at the beginning were non-serviceable hearing during the follow-up. Transient facial paralysis was observed in 3 (6.7%) patients. No statistically significant factor could be detected in LCR, hearing, and facial nerve preservation. Our findings are similar to previous SRT data regarding LCR, treatment failure, hearing preservation, and facial nerve impairment. SRT is an effective treatment method for AN with reasonable results. [Med-Science 2023; 12(3.000): 933-40

Factors affecting the mortality rate of patients with cancer hospitalized with COVID-19: a single center's experience

The main objective is to define the mortality of patients with cancer admitted to our hospital, their clinical and demographic characteristics, investigate the risk of COVID-19 for patients with cancer, and determine factors that affect the mortality rates of patients with cancer dying of COVID-19. A total of 2401 patients were admitted to our hospital with the diagnosis of COVID-19 from March 11th, 2020, to May 31st, 2020. Ninety-two out of a total of 112 cancer patients were included in this study based on the planned inclusion/exclusion criteria. The clinical, demographic, and laboratory features and treatments provided were studied, and their effect on mortality rates was analyzed. In our study the median age of the patients was 67 years, and 55.4% were male. More than half (56.5%) of our patients had metastasis. The mortality rate was 6.2% in the overall population with COVID-19, whereas it was 23.9% in patients with cancer. The mortality rate in patients with metastasis was statistically significantly higher compared with those without metastasis (34.0% vs. 10.3% P = 0.008). The mortality rate in patients still smoking was statistically significantly higher than in non-smokers (37.5% vs. 12.5% P = 0.033). The mortality rates of patients with high average C-reactive protein (CRP), ferritin, lactate dehydrogenase (LDH), and D-dimer levels were statistically significantly higher than in those without, and the mortality rates of patients with lower average albumin and hemoglobin levels were statistically significantly higher than those without (P < 0.001, P = 0.006, P = 0.041, P < 0.001, P < 0.001, and P = 0.028, respectively). Having metastases concurrent with COVID-19 was a statistically significant factor predictive of prognosis. Also, high CRP, ferritin, LDH, and D-dimer, and low albumin and hemoglobin were related to increased mortality rates. The predictive and prognostic role of possible factors related to prognosis is still unknown and further large, multicenter prospective studies are needed to confirm these results