Assessing the Role of Pt Clusters on TiO₂ (P25) on the Photocatalytic Degradation of Acid Blue 9 and Rhodamine B

The role of Pt on photocatalytic substrates such as TiO2 (P25) for the decomposition of organic pollutants is still controversial in the scientific community. The well-observed behavior of an optimum catalytic activity as a function of the Pt loading is usually explained by the shift from charge separation to charge recombination behavior of Pt clusters. However, experiments supporting this explanation are still lacking to give a concise understanding of the effect of Pt on the photocatalytic activity. Here, we present an experimental study that tries to discriminate the different effects influencing the photocatalytic activity. Using atomic layer deposition in a fluidized bed reactor, we prepared TiO2 (P25) samples with Pt loadings ranging from 0.04 wt % to around 3 wt %. In order to reveal the mechanism behind the photocatalytic behavior of Pt on P25, we investigated the different aspects (i.e., surface area, reactant adsorption, light absorption, charge transfer, and reaction pathway) of heterogeneous photocatalysis individually. In contrast to the often proposed prolonged lifetime of charge carriers in Pt-loaded TiO2, we found that after collecting the excited electrons, Pt acts more as a recombination center independent of the amount of Pt deposited. Only when dissolved O2 is present in the solution, charge recombination is suppressed by the subsequential consumption of electrons at the surface of the Pt clusters with the dissolved O2 benefited by the improved O2 adsorption on the Pt surface.</p

Assessing the Role of Pt Clusters on TiO₂ (P25) on the Photocatalytic Degradation of Acid Blue 9 and Rhodamine B

The role of Pt on photocatalytic substrates such as TiO2 (P25) for the decomposition of organic pollutants is still controversial in the scientific community. The well-observed behavior of an optimum catalytic activity as a function of the Pt loading is usually explained by the shift from charge separation to charge recombination behavior of Pt clusters. However, experiments supporting this explanation are still lacking to give a concise understanding of the effect of Pt on the photocatalytic activity. Here, we present an experimental study that tries to discriminate the different effects influencing the photocatalytic activity. Using atomic layer deposition in a fluidized bed reactor, we prepared TiO2 (P25) samples with Pt loadings ranging from 0.04 wt % to around 3 wt %. In order to reveal the mechanism behind the photocatalytic behavior of Pt on P25, we investigated the different aspects (i.e., surface area, reactant adsorption, light absorption, charge transfer, and reaction pathway) of heterogeneous photocatalysis individually. In contrast to the often proposed prolonged lifetime of charge carriers in Pt-loaded TiO2, we found that after collecting the excited electrons, Pt acts more as a recombination center independent of the amount of Pt deposited. Only when dissolved O2 is present in the solution, charge recombination is suppressed by the subsequential consumption of electrons at the surface of the Pt clusters with the dissolved O2 benefited by the improved O2 adsorption on the Pt surface.ChemE/Product and Process EngineeringChemE/Opto-electronic MaterialsRST/Luminescence MaterialsChemE/Afdelingsburea

Initial treatment of steroid-sensitive idiopathic nephrotic syndrome in children with mycophenolate mofetil versus prednisone: protocol for a randomised, controlled, multicentre trial (INTENT study)

Introduction Idiopathic nephrotic syndrome is the most common glomerular disease in childhood with an incidence of 1.8 cases per 100 000 children in Germany. The treatment of the first episode implies two aspects: induction of remission and sustainment of remission. The recent Kidney Disease Improving Global Outcomes, American Academy of Pediatrics and German guidelines for the initial treatment of the first episode of a nephrotic syndrome recommend a 12-week course of prednisone. Despite being effective, this treatment is associated with pronounced glucocorticoid-associated toxicity due to highdose prednisone administration over a prolonged period of time. The aim of the INTENT study (Initial treatment of steroid-sensitive idiopathic nephrotic syndrom in children with mycophenolate mofetil versus prednisone: protocol for a randomised, controlled, multicentre trial) is to show that an alternative treatment regimen with mycophenolic acid is not inferior regarding sustainment of remission, but with lower toxicity compared with treatment with glucocorticoids only. Methods and design The study is designed as an open, randomised, controlled, multicentre trial. 340 children with a first episode of steroid-sensitive nephrotic syndrome and who achieved remission by a standard prednisone regimen will be enrolled in the trial and randomised to one of two treatment arms. The standard care group will be treated with prednisone for a total of 12 weeks; in the experimental group the treatment is switched to mycophenolate mofetil, also for a total of 12 weeks in treatment duration. The primary endpoint is the occurrence of a treated relapse within 24 months after completion of initial treatment. Ethics and dissemination Ethics approval for this trial was granted by the ethics committee of the Medical Faculty of the University of Heidelberg (AFmu-554/2014). The study results will be published in accordance with the Consolidated Standards of Reporting Trials statement and the Standard Protocol Items: Recommendations for Interventional Trials guidelines. Our findings will be submitted to major international paediatric nephrology and general paediatric conferences and submitted for publication in a peer-reviewed, open-access journal

Tumor-targeted 4-1BB agonists for combination with T cell bispecific antibodies as off-the-shelf therapy

Endogenous costimulatory molecules on T cells such as 4-1BB (CD137) can be leveraged for cancer immunotherapy. Systemic administration of agonistic anti-4-1BB antibodies, although effective preclinically, has not advanced to phase 3 trials because they have been hampered by both dependency on Fc gamma receptor-mediated hyperclustering and hepatotoxicity. To overcome these issues, we engineered proteins simultaneously targeting 4-1BB and a tumor stroma or tumor antigen: FAP-4-1BBL (RG7826) and CD19-4-1BBL. In the presence of a T cell receptor signal, they provide potent T cell costimulation strictly dependent on tumor antigen-mediated hyperclustering without systemic activation by Fc gamma R binding. We could show targeting of FAP-4-1BBL to FAP-expressing tumor stroma and lymph nodes in a colorectal cancer-bearing rhesus monkey. Combination of FAP-4-1BBL with tumor antigen-targeted T cell bispecific (TCB) molecules in human tumor samples led to increased IFN-gamma and granzyme B secretion. Further, combination of FAP- or CD19-4-1BBL with CEA-TCB (RG7802) or CD20-TCB (RG6026), respectively, resulted in tumor remission in mouse models, accompanied by intratumoral accumulation of activated effector CD8(+) T cells. FAP- and CD19-4-1BBL thus represent an off-the-shelf combination immunotherapy without requiring genetic modification of effector cells for the treatment of solid and hematological malignancies