Dental Therapy of Patients Prior to Endoprostheses: A Retrospective, Telephone-Based Cohort Study

The aim of this study was to assess, whether patients prior to endoprosthesis (EP) visit their dentist for need-oriented therapy and whether this would be associated with the occurrence of complications. Based on a cohort of patients, which was orally investigated prior to EP surgery between 04/2020 and 12/2021, a telephone interview was performed at least six months after EP implantation. Patients were classified into either low-risk (LR), moderate-risk (MR), or high-risk (HR) groups. Participants were interviewed based on a structured questionnaire regarding dental visits, dental therapy, and potential complications during the observational period. Out of the 311 patients from the baseline cohort, 96 patients after EP implantation could be included (participation rate of 31%). Nineteen patients were in LR (20%), 41 in MR (43%), and 36 in the HR group (37%). Overall, 79% (n = 76) of the patients followed the recommendation to visit their dentist; 94% of patients within the HR group visited the dentist (p = 0.02). Dental treatment procedures included tooth cleaning (57%), periodontal treatment (31%), restorative therapy/filling (28%), and tooth extraction (28%). In 64% of the HR patients (n = 23), the potential oral foci with a risk of EP infection were eliminated by their general dentist. Fourteen different complications occurred within the observation period, without any group effect (p > 0.05). In conclusion, most patients prior to EP visit their general dentist following referral, especially if they have a potential oral focus. The effect of dental clearance on infectious complications of EP remains unclear, whereby further clinical studies are needed

Looking Deep inside the Cathode of Li-O2 Batteries: Unraveling the Local Distribution of Li2O2 with a Combined Experimental and Model-Based Approach

Carbon-based, high surface area gas diffusion electrodes (GDEs) are commonly used as cathodes in Li-O2 batteries. These GDEs provide an sufficient amount of active sites to deposit the main discharge product, Li2O2. Despite the fast electron transfer at the electrode surface to form Li2O2, experimental results show that the very high theoretical energy densities of Li-O2 batteries cannot be achieved at the moment. Instead of the desired formation of high amounts of soluble LiO2, predominantly insoluble Li2O2 precipitates at the active sites of the cathode during discharge. Unfortunately Li2O2 is poorly conductive for electrons, which leads to a low amount of deposited Li2O2 per active site and a fast passivation of the cathode. Thus, only the cathode surface area and not the pore volume is utilized by Li2O2, which explains the discrepancy between theory and experiments. Furthermore, the precipitation leads to continuous changes in porosity, available active surface area and predominant reaction pathway. For this reason a detailed analysis of the distribution of Li2O2 at all points in the GDE and of the factors that influence the Li2O2 morphology is needed to overcome performance limitations. [1]In this work, we elucidate how the local distribution of Li2O2 inside the GDE and its particle size evolve as a function of discharge current density. We apply a powerful combination of experimental and model-based analysis. To the best of our knowledge, this is the first study on the cathode surface utilization by Li2O2 and its particle sizes performed for different locations and states of discharge (SOD). The impact of the distribution and the resulting changes in transport resistance and active surface area on the battery performance are derived thereof. In the experimental part, decreasing capacities and Li2O2 particle sizes are observed for increasing discharge current densities (see SEM analysis of discharged battery cathodes in fig. 1 a)). Furthermore, the experimental results show that particle precipitation starts mainly at the side of the cathode that faces the oxygen reservoir of the battery (see fig. 1 b)). Discharging a battery at low current densities leads to a uniform cathode surface coverage by Li2O2 even at low SOD whereas discharging at high current densities yields a gradient of blocked active sites through the cathode. Simulations based on a physical GDE model show that a two-step reaction mechanism with the soluble species LiO2 as reaction intermediate can quantitatively explain the experimental findings. Depending on the current density, either a chemical or an electrochemical particle growth process predominates, which leads to the distinct different particle size distributions (see fig. 1 c) and d)). The strong dependence of capacity on the current density is related to different capacities per carbon cathode surface area at the end of discharge. At high discharge rates and thereby lowered potential more nucleation takes place. As a result, the particle number is higher and the average size smaller. Due to the surface volume ratio, smaller particles entail lower capacities per cathode surface area. The results point out that even at moderate current densities the battery capacity is limited by the surface area of the GDE and not by the concentration of dissolved O2 in the liquid electrolyte. Therefore, the solubility and reaction kinetics of the reaction intermediate LiO2 play a crucial role to enhance Li2O2 particle size and with it the obtainable discharge capacity. The presented results provide detailed insight into the cathode surface utilization and the underlying processes that limit the performance of GDEs in Li-O2 batteries. In the end, the study will help to achieve higher discharge capacities for this type of battery and thus will propel the ongoing research and the efforts in commercialization of metal-oxygen batteries

Early cognitive basic symptoms are accompanied by neurocognitive impairment in patients with an 'at-risk mental state' for psychosis

Aim: Patients with an increased risk for psychosis ('at-risk mental state' (ARMS)) present various neurocognitive deficits. Not least because of differences in identifying the ARMS, results of previous studies are inconsistent. In most studies ARMS-patients are classified by the experience of attenuated psychotic symptoms (APS) and/or brief limited intermittent psychotic symptoms (BLIPS). Few studies additionally assessed cognitive basic symptoms (BS). A comprehensive assessment in the very early stage of the ARMS is missing.Methods: In the present study we characterized ARMS‐patients for cognitive BS (ARMS‐BS), APS and BLIPS (ARMS‐A/B) according to the Early Recognition Inventory based on IRAOS (ERIraos). Furthermore, we assessed neurocognitive deficits using the MATRICS consensus cognitive battery for schizophrenia with a primary hypothesis regarding working memory performance. Groups of 38 ARMS‐patients and 38 healthy controls were matched for age, gender, education and premorbid verbal intelligence.Results: Between‐group comparisons revealed significant poorer working memory performance in addition to lower verbal learning and problem solving, slower processing speed and lower global neurocognitive functioning in ARMS‐patients as compared to controls. ARMS‐BS did not differ from ARMS‐A/B.Conclusions: These results underscore the presence of cognitive limitations in patients only presenting with cognitive BS. Knowledge of these early cognitive deviations supports the inclusion of early ARMS‐stages into a comprehensive concept of the psychosis risk state. Therapeutic interventions already applied at this stage might prevent deterioration of constraints. Longitudinal and interventional studies investigating the interaction of cognitive BS and neurocognitive as well as metacognitive deficits are warranted.publishe

Do young patients with renal cell carcinoma feature a distinct outcome after surgery? A comparative analysis of patients age 40 years or less versus patients in the seventh decade of life based on the multinational CORONA database

PURPOSE: We analyzed the distinct clinicopathological features and prognosis of patients with renal cell carcinoma age 40 years or less compared to a reference group of patients 60 to 70 years old. MATERIALS AND METHODS: Overall 2,572 patients retrieved from a multicenter international database comprised of 6,234 patients with surgically treated renal cell carcinoma were included in this retrospective study. Clinical and histopathological features of 297 patients 40 years old or younger (4.8%) were compared to those of 2,275 patients (36.5%) 60 to 70 years old, who served as the reference group. Median followup was 59 months. The impact of young age and further parameters on disease specific mortality and all cause mortality was evaluated by multivariate Cox proportional hazards regression analyses. RESULTS: Young patients more frequently underwent nephron sparing surgery (27% vs 20%, p = 0.008) and regional lymph node dissection compared to older patients (38% vs 32%, p = 0.025). Organ confined tumor stage (81% vs 70%, p <0.001), smaller tumor diameter (4.5 vs 4.7 cm, p = 0.014) and chromophobe subtype (10% vs 4%, p <0.001) were significantly more frequent in young patients. On multivariate analysis older patients had a higher disease specific (HR 2.21, p <0.001) and all cause mortality (HR 3.05, p <0.001). The c indices for the Cox models were 0.87 and 0.78, respectively. However, integration of the variable age group did not significantly increase the predictive accuracy of the disease specific and all cause mortality models. CONCLUSIONS: Young patients with renal cell carcinoma (40 years old or younger) have significantly different frequencies of clinical and histopathological features, and a significantly lower all cause and disease specific mortality compared to patients 60 to 70 years old