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Purpose In craniospinal irradiation, two or three isocenter groups along the craniocaudal axis are required to cover the long treatment target. Adapting the isocenter distance according to daily deviations in patient position is challenging because dosimetric hot or cold spots may occur in the field junction. The aim of this study was to quantify the effect of adapting the isocenter distance to patient position on the dose distribution of the field overlap region in craniospinal irradiation using partial‐arc volumetric modulated arc therapy. Methods The magnitude of isocenter distance deviations in craniocaudal direction was quantified by registering the setup images of 204 fractions of 12 patients to the planning images. The dosimetric effect of these deviations was determined by shifting the isocenters of the original treatment plan and calculating the resulting dose distribution. Results On fraction‐level, deviations larger than 3 mm caused more than 5 percentage point changes in the doses covering 2% (D2%) and 98% (D98%) of the junction volume in several patients. On treatment course‐level, the changes in D2% and D98% of the junction volume were less than 5 percentage points in all cases except for one patient. Conclusions Craniocaudal isocenter distance adaptation can be conducted provided that the mean isocenter distance deviation over the treatment course is within 3 mm.

Nucleation is a fundamental step in atmospheric new-particle formation. However, laboratory experiments on nucleation have systematically failed to demonstrate sulfuric acid particle formation rates as high as those necessary to account for ambient atmospheric concentrations, and the role of sulfuric acid in atmospheric nucleation has remained a mystery. Here, we report measurements of new particles (with diameters of approximately 1.5 nanometers) observed immediately after their formation at atmospherically relevant sulfuric acid concentrations. Furthermore, we show that correlations between measured nucleation rates and sulfuric acid concentrations suggest that freshly formed particles contain one to two sulfuric acid molecules, a number consistent with assumptions that are based on atmospheric observations. Incorporation of these findings into global models should improve the understanding of the impact of secondary particle formation on climate.

Background Idiopathic intracranial hypertension (IIH) is a rare disease of unknown aetiology related possibly to disturbed cerebrospinal fluid (CSF) dynamics and characterised by elevated intracranial pressure (ICP) causing optic nerve atrophy if not timely treated. We studied CSF dynamics of the IIH patients based on the available literature and our well-defined cohort. Method A literature review was performed from PubMed between 1980 and 2020 in compliance with the PRISMA guideline. Our study includes 59 patients with clinical, demographical, neuro-ophthalmological, radiological, outcome data, and lumbar CSF pressure measurements for suspicion of IIH; 39 patients had verified IIH while 20 patients did not according to Friedman’s criteria, hence referred to as symptomatic controls. Results The literature review yielded 19 suitable studies; 452 IIH patients and 264 controls had undergone intraventricular or lumbar CSF pressure measurements. In our study, the mean CSF pressure, pulse amplitudes, power of respiratory waves (RESP), and the pressure constant (P 0 ) were higher in IIH than symptomatic controls ( p < 0.01). The mean CSF pressure was higher in IIH patients with psychiatric comorbidity than without ( p < 0.05). In IIH patients without acetazolamide treatment, the RAP index and power of slow waves were also higher ( p < 0.05). IIH patients with excess CSF around the optic nerves had lower relative pulse pressure coefficient (RPPC) and RESP than those without ( p < 0.05). Conclusions Our literature review revealed increased CSF pressure, resistance to CSF outflow and sagittal sinus pressure (SSP) as key findings in IIH. Our study confirmed significantly higher lumbar CSF pressure and increased CSF pressure waves and RAP index in IIH when excluding patients with acetazolamide treatment. In overall, the findings reflect decreased craniospinal compliance and potentially depleted cerebral autoregulation resulting from the increased CSF pressure in IIH. The increased slow waves in patients without acetazolamide may indicate issues in autoregulation, while increased P 0 could reflect the increased SSP.

Cloud cover at CERN A substantial source of cloud condensation nuclei in the atmospheric boundary layer is thought to originate from the nucleation of trace sulphuric acid vapour. Despite extensive research, we still lack a quantitative understanding of the nucleation mechanism and the possible role of cosmic rays, creating one of the largest uncertainties in atmospheric models and climate predictions. Jasper Kirkby and colleagues present the first results from the CLOUD experiment at CERN, which studies nucleation and other ion-aerosol cloud interactions under precisely controlled conditions. They find that atmospherically relevant ammonia mixing ratios of 100 parts per trillion by volume increase the nucleation rate of sulphuric acid particles by more than a factor of 100 to 1,000. They also find that ion-induced binary nucleation of H 2 SO 4 –H 2 O can occur in the mid-troposphere, but is negligible in the boundary layer and so additional species are necessary. Even with the large enhancements in rate caused by ammonia and ions, they conclude that atmospheric concentrations of ammonia and sulphuric acid are insufficient to account for observed boundary layer nucleation. Atmospheric aerosols exert an important influence on climate 1 through their effects on stratiform cloud albedo and lifetime 2 and the invigoration of convective storms 3 . Model calculations suggest that almost half of the global cloud condensation nuclei in the atmospheric boundary layer may originate from the nucleation of aerosols from trace condensable vapours 4 , although the sensitivity of the number of cloud condensation nuclei to changes of nucleation rate may be small 5 , 6 . Despite extensive research, fundamental questions remain about the nucleation rate of sulphuric acid particles and the mechanisms responsible, including the roles of galactic cosmic rays and other chemical species such as ammonia 7 . Here we present the first results from the CLOUD experiment at CERN. We find that atmospherically relevant ammonia mixing ratios of 100 parts per trillion by volume, or less, increase the nucleation rate of sulphuric acid particles more than 100–1,000-fold. Time-resolved molecular measurements reveal that nucleation proceeds by a base-stabilization mechanism involving the stepwise accretion of ammonia molecules. Ions increase the nucleation rate by an additional factor of between two and more than ten at ground-level galactic-cosmic-ray intensities, provided that the nucleation rate lies below the limiting ion-pair production rate. We find that ion-induced binary nucleation of H 2 SO 4 –H 2 O can occur in the mid-troposphere but is negligible in the boundary layer. However, even with the large enhancements in rate due to ammonia and ions, atmospheric concentrations of ammonia and sulphuric acid are insufficient to account for observed boundary-layer nucleation.

•Psychiatric disorders are sevenfold more common in IIH patients compared to general population.•The IIH patients with pre-existing psychiatric diagnosis had more often empty sella at diagnosis.•The IIH patients with a pre-existing psychiatric diagnosis have worse subjective outcome. Idiopathic intracranial hypertension (IIH) is aetiologically unknown disorder that associates with endocrinological disturbances, including dysfunction of hypothalamic-pituitary-adrenal-axis. Neuroendocrinological dysfunctions have also been characterized in psychiatric disorders, and therefore we investigated the presence of psychiatric disorders of patients with IIH in a well-defined cohort. A total of 51 patients with IIH were included. Patient demographics, symptoms, imaging data, ophthalmological and clinical findings were collected. At the time of diagnosis the mean age was 32.5years (SD 10.7), the body mass index was 37.1 kg/m2 (SD 7.4), and the opening pressure 29.1 mmHg (SD 6.2). A total of 88.2% of patients were female and 45.1% were diagnosed with a psychiatric co-morbidity prior to IIH diagnosis. The mean follow-up time was 4.4 years (SD 5.4). The overall treatment outcome was significantly poorer on a group of patients with psychiatric diagnosis when compared to individuals without such history (p = 0.001), but there were no differences in the resolution of papilledema (p = 0.405). Patients with IIH and psychiatric disorders had more often empty sella on their imaging at diagnosis when compared to patients without psychiatric co-morbidity (p = 0.044). Psychiatric disorders are highly prevalent in patients with IIH and associate with worse subjective outcomes. These findings advocate for monitoring the mental health of patients with IIH and warrant further multidisciplinary research to understand the potentially underlying psychosocial and neuroendocrinological mechanisms.

Levänluhta is a unique archaeological site with the remains of nearly a hundred Iron Age individuals found from a water burial in Ostrobothnia, Finland. The strongest climatic downturn of the Common Era, resembling the great Fimbulvinter in Norse mythology, hit these people during the 6th century AD. This study establishes chronological, dietary, and livelihood synthesis on this population based on stable carbon and nitrogen isotopic and radiocarbon analyses on human remains, supported by multidisciplinary evidence. Extraordinarily broad stable isotopic distribution is observed, indicating three subgroups with distinct dietary habits spanning four centuries. This emphasizes the versatile livelihoods practiced at this boundary of marine, freshwater, and terrestrial ecosystems. While the impact of the prolonged cold darkness of the 6th century was devastating for European communities relying on cultivation, the broad range of livelihoods provided resilience for the Levänluhta people to overcome the abrupt climatic decline.