Intramolecular locking and coumarin insertion: a stepwise approach for TADF design

Three novel TADF (thermally activated delayed fluorescence) emitters based on the well-studied Qx-Ph-DMAC fluorophore are designed and synthesized. The photophysical properties of these materials are studied from a theoretical and experimental point of view, demonstrating the cumulative effects of multiple small modifications that combine to afford significantly improved TADF performance. First, an extra phenyl ring is added to the acceptor part of Qx-Ph-DMAC to increase the conjugation length, resulting in BQx-Ph-DMAC, which acts as an intermediate molecular structure. Next, an electron-deficient coumarin unit is incorporated to fortify the electron accepting ability, affording ChromPy-Ph-DMAC with red-shifted emission. Finally, the conjugated system is further enlarged by 'locking' the molecular structure, generating DBChromQx-DMAC with further red-shifted emission. The addition of the coumarin unit significantly impacts the charge-transfer excited state energy levels with little effect on the locally excited states, resulting in a decrease of the singlet-triplet energy gap. As a result, the two coumarin-based emitters show considerably improved TADF performance in 1 w/w% zeonex films when compared to the initial Qx-Ph-DMAC structure. 'Locking' the molecular structure further lowers the singlet-triplet energy gap, resulting in more efficient reverse intersystem crossing and increasing the contribution of TADF to the total emission.

Deletion of GARP on mouse regulatory T cells is not sufficient to inhibit the growth of transplanted tumors

GARP is a transmembrane protein that presents latent TGF-β1 on the surface of regulatory T cells (Tregs). Neutralizing anti-GARP monoclonal antibodies that prevent the release of active TGF-β1, inhibit the immunosuppressive activity of human Tregs in vivo. In this study, we investigated the contribution of GARP on mouse Tregs to immunosuppression in experimental tumors. Unexpectedly, Foxp3 conditional garp knockout (KO) mice challenged orthotopically with GL261 tumor cells or subcutaneously with MC38 colon carcinoma cells did not show prolonged survival or delayed tumor growth. Also, the suppressive function of KO Tregs was similar to that of wild type Tregs in the T cell transfer model in allogeneic, immunodeficient mice. In conclusion, garp deletion in mouse Tregs is not sufficient to impair their immunosuppressive activity in vivo.

Influence of the amorphous phase and preceding solution processing on the eutectic behaviour in the state diagram of P3HT : PC61BM determined by rapid heat–cool calorimetry

Experimental determination of eutectic state diagrams for organic photovoltaics based on advanced calorimetry highlighting the importance of the amorphous phase.

Functionalization of boron-doped nanocrystalline diamond with N3 dye molecules

N3 dye molecules [cis-bis(isothiocyanato)bis(2,2'-bipyridyl-4,4'-dicarboxylato)ruthenium(II)] are covalently attached to boron-doped nanocrystalline diamond (B:NCD) thin films through a combination of coupling chemistries, i.e., diazonium, Suzuki, and EDC-NHS. X-ray and ultraviolet photoelectron spectroscopy and near-edge X-ray absorption fine structure spectroscopy are used to verify the covalent bonding of the dye on the B:NCD surface (compared to a hydrogen-terminated reference). The spectroscopic results confirm the presence of a dense N3 chromophore layer, and the positions of the frontier orbitals of the dye relative to the band edge of the B:NCD thin film are inferred as well. Proof-of-concept photoelectrochemical measurements show a strong increase in the photocurrent compared to non-dye-functionalized B:NCD films. This study opens up the possibility of applying N3-sensitized B:NCD thin films as hole conductors in dye-sensitized solar cells.

Combined experimental-theoretical NMR study on 2,5-bis(5-aryl-3-hexylthiophen-2-yl)-thiazolo[5,4-d]thiazole derivatives for printable electronics

Four 2,5-bis(5-aryl-3-hexylthiophen-2-yl)thiazolo[5,4-d]thiazole derivatives have been synthesized and thoroughly characterized. The extended aromatic core of the molecules was designed to enhance the charge transport characteristics, and solubilizing hexyl side chains were introduced on the thiophene subunits to enable possible integration of these semiconducting small molecules in printable electronics. Complete elucidation of the chemical structures by detailed one-dimensional/two-dimensional NMR spectroscopy is described, providing interesting input for chemical shift prediction software as well, because limited experimental data on these types of compounds are currently available. Furthermore, theoretical calculations have assisted experimental observations--giving support for the chemical shift assignment and providing a springboard for future screening and predictions--demonstrating the benefits of a coordinated theoretical-experimental approach.

Technical advancement in regulatory T cell isolation and characterization using CD127 expression in patients with malignant glioma treated with autologous dendritic cell vaccination

We have successfully treated over two hundred high-grade glioma (HGG) patients with immunotherapy consisting of vaccination with autologous dendritic cells (DCs) loaded with autologous tumour lysate. It has been documented that regulatory T cells (Treg) can counteract anti-tumour immune responses. Therefore, monitoring of Treg in these patients is essential. Up till now, Treg have been characterized based on the expression of the transcription factor Foxp3. Here, we validated IL-7 receptor alpha subunit (CD127)dim expression as a marker for human Treg within HGG patients, as a less laborious assay for routine use in tumour vaccination trials. We noted a strong positive correlation between Foxp3 expression and CD127dim expression in CD4+CD25+ and CD4+ cells. The suppressive function of CD4+CD127dim cells was assessed in an allogeneic mixed lymphocyte reaction (MLR). We conclude that CD127 staining is a fast, well-suited and reproducible Treg monitoring tool in HGG patients treated with immunotherapy.

In vivo bioluminescence imaging in an experimental mouse model for dendritic cell based immunotherapy against malignant glioma

The value of bioluminescence imaging (BLI) for experimental cancer models has become firmly established. We applied BLI to the GL261 glioma model in the context of dendritic cell (DC) immunotherapy. Initial validation revealed robust linear correlations between in vivo, ex vivo and in vitro luciferase activity measurements. Ex vivo BLI demonstrated midline crossing and leakage of tumor cells. Orthotopically challenged mice followed with BLI showed an initial adaptation phase, after which imaging data correlated linearly with stereologically determined tumor dimensions. Transition from healthy to moribund state corresponded with an increasing in vivo flux but the onset of neurological deficit was clearly delayed compared to the onset of in vivo flux increase. BLI was implemented in prophylactic immunotherapy and imaging data were prognostic for therapy outcome. Three distinct response patterns were detected. Our data underscore the feasibility of in vivo BLI in an experimental immunotherapeutic setting in the GL261 glioma model.

Raising questions in clinical practice

Answers are required by family physicians to numerous questions during a day of patient care. This study examined the number of questions that arose during one day to which family physicians did not have an answer, the library resources to which the family physicians had access and used, and the relationship between the number of questions that arose in practice and library resources or use. Volunteer family physicians (N = 87) reported a mean of 6.8 questions. When accessing libraries, physicians relied primarily on their office and home libraries. Personal libraries had fewer than ten textbooks published since 1980 and subscriptions to fewer than five journals. T-test analysis indicated that the physician with the most questions practiced in the medical school community, was a graduate of a Canadian or United States medical school, and attended a course on problem raising and solving. The number of questions did not differ by the holdings in the physician's library, the age or sex profile of the patients, the number of patients seen or the frequency with which the physician used his personal library. Medical educators and librarians should provide educational opportunities to assist family physicians develop their personal libraries, their problem solving skills and their use of modern technology to access the literature.