Publications by authors named "Alexander Horn"

Objective: Gamma Knife radiosurgery (GKRS) is a treatment option for refractory trigeminal neuralgia (TN). However, there is a paucity of data regarding the effectiveness of GKRS for relapsing TN following microvascular decompression (MVD). The aim of this study was to characterize the response rate, complications, pain relief durability, and predictors of pain relapse for salvage GKRS following MVD for TN.

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Neuroendocrine analyses of posttraumatic stress disorder (PTSD) have generally focused on hypothalamic-pituitary-adrenal (HPA) axis alterations. In the present analyses, we examine two additional neuroendocrine factors that have been previously implicated in biological stress responses: oxytocin (OT) and arginine vasopressin (AVP). Here we examined basal neuropeptide status in military veterans clinically diagnosed with PTSD (n = 29) and in two non-traumatized comparison groups with previous stress exposure (n = 11 SWAT trainees and n = 21 ultramarathon runners).

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Background And Objectives: ChatGPT is a natural language processing chatbot with increasing applicability to the medical workflow. Although ChatGPT has been shown to be capable of passing the American Board of Neurological Surgery board examination, there has never been an evaluation of the chatbot in triaging and diagnosing novel neurosurgical scenarios without defined answer choices. In this study, we assess ChatGPT's capability to determine the emergent nature of neurosurgical scenarios and make diagnoses based on information one would find in a neurosurgical consult.

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Background: Diminished systemic serum butyrylcholinesterase (BChE), a biomarker for chronic inflammation, cachexia, and advanced tumor stage, has shown to play a prognostic role in various malignancies. The aim of this study was to investigate the prognostic value of pretherapeutic BChE levels in patients with resectable adenocarcinoma of the gastroesophageal junction (AEG), treated with or without neoadjuvant therapy.

Methods: Data of a consecutive series of patients with resectable AEG at the Department for General Surgery, Medical University of Vienna, were analyzed.

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Matteson homologations of chiral boronic esters proved to be an excellent tool for the synthesis of highly functionalized amino and hydroxy acid residues. This method provides straightforward stereoselective access to the side chain of callipeltin A, a natural marine product with interesting biological activities. Furthermore, this protocol should allow for variations in the substitution pattern in future SAR studies, simply by choosing suitable nucleophiles during the homologation steps.

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Mammals, including humans, are reliant for survival and reproduction on adaptations associated with sociality and physiological investment, which can be linked to interactions with their parents or other bonded adult conspecifics. A wide range of evidence in human and non-human mammal species links social behaviors and relationships - including those characterized by what humans call "love" - to positive health and longevity. In light of this evidence, we propose a Social Dependency Hypothesis of Longevity, suggesting that natural selection has favored longer and healthier adult lives in species or in individuals exhibiting enhanced caregiver responsibilities contributing to the success of the next generation.

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Both paralogs of the calcium-dependent activator protein for secretion (CAPS) are required for exocytosis of synaptic vesicles (SVs) and large dense core vesicles (LDCVs). Despite approximately 80% sequence identity, CAPS1 and CAPS2 have distinct functions in promoting exocytosis of SVs and LDCVs in dorsal root ganglion (DRG) neurons. However, the molecular mechanisms underlying these differences remain enigmatic.

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Excitons dominate the light absorption and re-emission spectra of monolayer transition-metal dichalcogenides (TMD). Microscopic investigations of the excitonic response in TMD almost invariably extract information from the radiative recombination step, which only constitutes one part of the picture. Here, by exploiting imaging spectroscopic ellipsometry (ISE), we investigate the spatial dependence of the dielectric function of chemical vapor deposition (CVD)-grown WS flakes with a microscopic lateral resolution, thus providing information about the spatially varying, exciton-induced light absorption in the monolayer WS.

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The interaction of ultrashort pulsed laser radiation with intensities of 10 W cm and above with materials often results in an unexpected high X-ray photon flux. It has been shown so far, on the one hand, that X-ray photon emissions increase proportionally with higher laser power and the accumulated X-ray dose rates can cause serious health risks for the laser operators. On the other hand, there is clear evidence that little variations of the operational conditions can considerably affect the spectral X-ray photon flux and X-ray emissions dose.

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Local crystallization of ferromagnetic layers is crucial in the successful realization of miniaturized tunneling magnetoresistance (TMR) devices. In the case of Co-Fe-B TMR devices, used most successfully so far in applications and devices, Co-Fe-B layers are initially deposited in an amorphous state and annealed post-deposition to induce crystallization in Co-Fe, thereby increasing the device performance. In this work, first direct proof of locally triggered crystallization of 10 nm thick Co-Fe-B films by laser irradiation is provided by means of X-ray diffraction (XRD) using synchrotron radiation.

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Prior carburization of semi-finished steel sheets is a new process variant in hot stamping to manufacture parts with tailored properties. Compared to conventional hot stamping processes, a complex phase typed steel alloy is used instead of 22MnB5. Yet recent investigations focused on final mechanical properties rather than microstructural mechanisms cause an increase in strength.

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Despite evidence supporting a role for oxytocin (OT) in regulating social behavior, surprisingly little is known about how this neuropeptide is calibrated during development. We systematically reviewed empirical studies in humans (k = 86 publications reporting on 66 independent samples; N = 7319) that examined associations between early-life stress and three OT system components: endogenous OT, methylation of the OT receptor gene (OXTRm), and biological and behavioral responses to intranasally administered OT. In a series of meta-analyses, we found some evidence that people who grew up under more adverse conditions tend to have lower endogenous OT (children: r = .

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N-(α-Hydroxyacyl)-glycinesters can be used as excellent nucleophiles in Pd-catalyzed allylic alkylation. The method allows for the stereoselective introduction of a wide range of side chains, including highly functionalized ones. Both diastereomers can be accessed through variation of the reaction conditions.

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Purpose: As previous data had shown that only two-thirds of patients had the predicted activity time courses when PEG-asparaginase 1000 U/m(2) was used in reinduction after native E. coli asparaginase in induction treatment of acute lymphoblastic leukaemia (ALL), drug monitoring was performed with the use of a higher dose.

Methods: Because one-third of patients had insufficient serum asparaginase activity time courses after a single dose of 1000 U/m(2) PEG-asparaginase during reinduction treatment, a dose of 2500 U/m(2) PEG-asparaginase, which is the approved dosage in Germany, was used in 39 reinduction and 20 relapse patients to determine whether prolongation of the activity time course may be possible with this higher dose, and to look for significant differences between reinduction and relapse patients.

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