Philipps University of Marburg

Let M be the moduli space of holomorphic r -bundles E with c 1 ( E ) = 0 and c 2 ( E ) = 1 on the blowup of P 2 = C 2 ∪ ℓ ∞ at 0 ∈ C 2 that are framed along the line ℓ ∞ at infinity. With respect to the standard Kähler metric on P ˜ 2 ﹨ ℓ ∞ , an explicit formula for a potential for the Weil-Petersson Kähler form for M is computed in this elementary case. A 1-parameter family of such potentials corresponding to a family of Kähler metrics degenerating to the pull-back of the flat metric on P 2 ﹨ ℓ ∞ is also constructed, and this is shown to converge to the standard form for such bundles on P 2 .

Stent-assisted coiling is widely used for the treatment of wide-necked intracranial aneurysms. The pEGASUS-HPC stent features a hydrophilic polymer coating designed to reduce thrombogenicity, potentially improving safety, particularly in ruptured aneurysms and complex configurations. To evaluate the safety, efficacy, and technical feasibility of stent-assisted coiling using the pEGASUS-HPC stent in the treatment of wide-necked intracranial aneurysms. We retrospectively analyzed 223 patients with 251 wide-necked aneurysms treated at six centers between July 2021 and March 2025. Primary endpoints included angiographic occlusion (modified Raymond-Roy classification, MRRC), periprocedural complications, and clinical outcome (modified Rankin Scale, mRS) at discharge and follow-up. Subgroup analysis was performed for ruptured aneurysms and bifurcation cases requiring Y-stenting. Stent deployment and coiling were technically successful in all cases. Immediate complete occlusion (MRRC I) was achieved in 92.4% of aneurysms, increasing to 96.8% at follow-up. The overall retreatment rate was 2.2%. Periprocedural complications occurred in 1.6% of cases, consisting of two minor perforations in unruptured aneurysms, both managed without clinical consequences. In ruptured cases a favorable outcome (mRS ≤2) was observed in 71.1%, with mortality confined to Hunt and Hess grade V or basilar artery aneurysms. Y-stenting was performed in 15.9% of cases without technical failure. No perforations occurred in ruptured cases. Stent-assisted coiling with the pEGASUS-HPC stent appears technically feasible and effective for wide-necked aneurysms, including acute ruptured cases and those requiring Y-stenting, with high occlusion rates and low complication rates.

When compared to their aryl-substituted counterparts, the chemistry of alkyl bismuth cations is still in its infancy. In order to tackle this synthetic challenge and close this gap of knowledge, we have developed protocols for the synthesis of precursors with unusual bismacyclic motifs and cyclopropyl ligands, Bi(CH2)5Br and BicPr2Cl. These and the more common precursor BiiPr2Cl could be turned into the cationic species [BiR2(SbF6)] (R2=(CH2)5, cPr2, iPr2), the first examples of alkyl bismuth cations with longer alkyl chains and cyclic motifs. The ability of these compounds to act as soft Z-type ligands is demonstrated by the formation of metal-only Lewis pairs in reactions with the platinum(0) precursor [Pt(PCy3)2]. The products of these reactions [(PCy3)2Pt→BiR2(SbF6)] show unsupported Pt→Bi bonds, and could be isolated and fully characterized. Pt oxidation and ring-opening of the cyclopropyl ligand were uncovered as a decomposition pathway.

Incorporation of the nephelauxetic effect into ligand design enabled red-shifting of spin-flip transitions of CrIII and MnIV complexes into the near-infrared region. Using carbazolide complexes as a model, we present a strategy for tuning the ratio of ligand field strength to the Racah parameter B by combining a covalent carbazolide core with variable σ-donor ligand "side arms." Substitution of pyridine, as in [Cr(Lpy)2]+ ([Lpy]- = 3,6-di-tert-butyl-1,8-di(pyridin-2-yl)carbazol-9-ide), with stronger σ-donors such as N-heterocyclic or mesoionic carbenes in [Cr(LNHC)2]+ or [Cr(LMIC)2]+ ([LNHC]- = 3,6-di-tert-butyl-1,8-bis(imidazolin-2-yliden-1-yl)carbazolide and [LMIC]- = 3,6-di-tert-butyl-1,8-bis(4,5,6,7-tetrahydro-2H-[1,2,3]triazolo[1,5-a]pyridin-2-yl)-carbazol-9-ide) increased the ligand field strength from 17 500 to 24 400 cm-1, with only a modest rise in B from 550 to 600 cm-1. This balance favors near-infrared spin-flip transitions while extending their excited-state lifetimes. Despite these advances, carbazolide-based ligands exhibit also drawbacks, including low-lying charge-transfer states and geometric distortions, which limit lifetimes and prevent emission, contrasting with other near-infrared-emissive CrIII systems. Additionally, we demonstrate an approach for estimating energies of dark, low-energy spin-flip states in CrIII complexes via photoinduced electron transfer and Rehm-Weller analysis. Our results offer guidance on balancing ligand field strength and metal-ligand bond covalency to optimize the photophysical and photochemical properties of first-row transition metal complexes.

The study we describe focuses on evaluating the effectiveness of linear accelerator (LINAC) stereotactic radiosurgery (SRS) in the treatment of cerebral arteriovenous malformations (AVMs). This treatment option is gaining interest due to the uncertainties associated with combined radiosurgical and endovascular treatments and the significant technological advancements in SRS. The primary goals of the study are to assess rates of obliteration (successful closure of the AVM) and rebleeding (the recurrence of bleeding posttreatment), as well as to identify factors influencing obliteration rates and to document any adverse effects associated with the procedure. The study retrospectively analyzed data from 134 patients treated with LINAC-based SRS for cerebral AVMs. The patients were categorized based on their prior treatments: 50had undergone partial embolization, 8had received acombination of embolization and surgery and 1patient had asurgical intervention. Furthermore, 75patients had received no prior treatment. Kaplan-Meier survival analysis and log-rank tests were employed to calculate actuarial obliteration rates and annual cumulative bleeding rates following SRS treatment. The study found that obliteration rates after SRS treatment increased over time, with 5‑year obliteration rates of 85.2% for grades I-II, 76.4% for gradeIII, and 62.1% for grades IV-V. Annual cumulative bleeding rates post-SRS were 1.5% for the first year and 0.7% for the second year. Interestingly, prior embolization did not affect the obliteration rate. The median time to obliteration was 36months (range 7-162 months). Obliteration rates were significantly better in Spetzler-Martin (SM) gradeI-II (85% at 5years) compared to gradeIII-V (68% at 5years, p = 0.01). Age, sex, and pediatric status had no statistically significant influence on AVM response to SRS. No radiation necrosis was observed in our cohort. This study contributes to the body of evidence supporting the effectiveness of SRS in treating cerebral AVMs and provides valuable insights into factors affecting treatment outcomes. The findings suggest that patients can expect ahigh chance of successful obliteration of the AVM with minimal adverse effects, making SRS acompelling option for those affected by this condition.

Schizophrenia encompasses positive, negative, and cognitive symptoms, and accumulating evidence suggests that the orexin system may modulate circuits relevant to these domains. Here, we investigated whether orexin-related interventions influence schizophrenia-like behaviors induced by the NMDA receptor antagonist dizocilpine in female and male mice. Two distinct approaches were used: nasal orexin A administration and chemogenetic activation of orexin neurons via DREADDs. Behavioral assessments included prepulse inhibition (PPI), locomotion and exploratory activity in the open field, social behavior, and working memory in the Y-maze. Overall, dizocilpine robustly induced schizophrenia-like phenotypes across these paradigms. Nasal orexin A exacerbated the dizocilpine-induced PPI deficit but attenuated the associated increase in startle reactivity, did not modify dizocilpine-induced hyperactivity, and partially rescued working memory impairments. Chemogenetic activation reproduced the PPI pattern observed with nasal orexin A, increased locomotion in both control- and dizocilpine-treated mice, induced anxiolytic-like effects in the open field, restored exploratory rearing, facilitated social recognition, and fully rescued working memory deficits. In some cases, the effects of these orexin-related interventions were differently pronounced in the two sexes. These findings indicate that activating the orexin system may worsen behavioral endophenotypes related to positive symptoms while alleviating those associated with negative and cognitive symptoms. However, substantial variability across assays, potentially related to the dosing of dizocilpine, orexin A, and CNO, as well as protocol-dependent constraints in some behavioral paradigms, limits definitive interpretation. Nevertheless, the present data reveal novel and domain-specific effects of orexin signaling in schizophrenia-relevant behavioral circuits and highlight the importance of exploring interventions with intermediate efficacy, including newly emerging orexin receptor agonists, to more precisely delineate orexin-dependent mechanisms and their therapeutic potential for negative and cognitive symptom domains.

Many flying insects, such as bees, wasps, and hoverflies, live aboveground, but depend on soil for nesting, development, and overwintering. In agricultural landscapes, soil is managed for production and therefore frequently subjected to disturbances such as ploughing, potentially influencing flying insects during their belowground life stages. To investigate the effects of ploughing on ground-nesting flying insects, we conducted a two-year field experiment in twelve wildflower strips. All strips were ploughed and sown during establishment and were 0, 1, 2 or 3 years old at the start of the experiment. Within wildflower strips, we compared unploughed control plots with adjacent treatment plots that were ploughed between the two sampling years. This design allowed us to assess the ploughing effect across different ages and whether time since establishment influenced insects. We used emergence traps to sample insects emerging from the soil and measured insect biomass, abundance, and body size. We found that ploughing substantially reduced ground-nesting flying insect biomass. When wildflower strips were left unploughed, biomass increased rapidly, particularly during the first years after their establishment. Ploughing consistently reduced insect biomass to equally low levels regardless of how long the wildflower strips had been established. This was driven primarily by declines in the abundance of large insects. Our findings highlight that even moderate reductions in ploughing frequency - for example, only every second year - can benefit ground-nesting flying insects and point to the potential for incorporating reduced ploughing frequencies into agricultural management and agri-environmental schemes. • Ploughing reduced the biomass of ground-nesting insects in wildflower strips. • Biomass rose rapidly in unploughed sites, especially during the first years. • Biomass dropped to equally low levels after ploughing, regardless of recovery time. • Large insects were most affected by ploughing, causing biomass drops. • Reducing ploughing, even to every two years, enhances insect biomass.

Stereotactic radiotherapy (SRT) is astandard treatment for vestibular schwannoma (VS). Long-term comparative data on single-fraction radiosurgery (SRS) versus normofractionated SRT (NFSRT) are limited. We retrospectively analyzed 175 VS patients treated between 1998 and 2023 (SRS n = 69; NFSRT n = 106; median age61years; median follow-up 46months). Tumor control was evaluated with Kaplan-Meier and Cox regression. Group differences were tested with Mann-WhitneyU and chi-square/Fisher's exact tests. Symptom changes were assessed with McNemar tests, and binary logistic regression identified predictors of acute and late toxicity. Overall, in-field PFS was 94.3% and out-field was PFS was 99.4%. All 10recurrences (median 58.5months) occurred in NFSRT patients treated with 55.8-56 Gy. Higher total dose predicted recurrence (HR = 2.97; p = 0.003). At baseline, 97.1% reported symptoms (hearing loss 86.9%, vertigo 48.0%, tinnitus 42.3%). After therapy, symptoms remained stable, except the incidence of headache, which increased from 14.3% to 22.3% (p = 0.02). Early toxicities were more common after NFSRT, including headache (OR = 4.05; p = 0.01), fatigue (OR = 5.12; p = 0.01), and alopecia (OR = 19.9; p = 0.04), but had resolved by late follow-up. Age and prior surgery predicted vertigo patterns over time. Radionecrosis was rare (0.6%). Both SRS and NFSRT achieve excellent long-term tumor control with low severe toxicity. For NFSRT, normofractionated doses above 55 Gy did not improve efficacy and may increase the recurrence risk, supporting moderate-dose regimens (50-54 Gy). Symptom stabilization confirms the safety of SRT, though headache and vertigo remain relevant long-term issues. Careful dose selection, patient counseling, and rehabilitation are essential to optimize outcomes.