Development and preliminary results of a large-pixel two-layer LaBr_(3) Compton camera prototype

Lanthanum bromide(LaBr_(3))crystal has a high energy resolution and time resolution and has been used in Compton cameras(CCs)over the past few decades.However,LaBr_(3) crystal arrays are difficult to process because LaBr_(3) is easy to crack and break;thus,few LaBr_(3)-based CC prototypes have been built.In this study,we designed and fabricated a large-pixel LaBr_(3) CC prototype and evaluated its performance with regard to position,energy,and angular resolution.We used two 10×10 LaBr_(3) crystal arrays with a pixel size of 5 mm×5 mm,silicon photomultipliers(SiPMs),and corresponding decoding circuits to construct our prototype.Additionally,a framework based on a Voronoi diagram and a lookup table was developed for list-mode projection data acquisition.Monte Carlo(MC)simulations based on Geant4 and experiments were conducted to evaluate the performance of our CC prototype.The lateral position resolution was 5 mm,and the maximum deviation in the depth direction was 2.5 and 5 mm for the scatterer and absorber,respectively.The corresponding measured energy resolu-tions were 7.65%and 8.44%,respectively,at 511 keV.The experimental results of ^(137)Cs point-like sources were consistent with the MC simulation results with regard to the spatial positions and full widths at half maximum(FWHMs).The angular resolution of the fabricated prototype was approximately 6°when a point-like ^(137)Cs source was centrally placed at a distance of 5 cm from the scatterer.We proposed and investigated a large-pixel LaBr_(3) CC for the first time and verified its feasibility for use in accurate spatial positioning of radiative sources with a high angular resolution.The proposed CC can satisfy the requirements of radiative source imaging and positioning in the nuclear industry and medical applications.

Anti-BCMA CAR T-cell therapy CT103A in relapsed or refractory AQP4-IgG seropositive neuromyelitis optica spectrum disorders:phase 1 trial interim results

Chimeric antigen receptor(CAR)T-cell therapy that targets B-cell maturation antigen(BCMA)have great potentials in autoimmune diseases and could be novel therapeutics for relapsed/refractory neuromyelitis optica spectrum disorder(NMOSD).To evaluate the safety and efficacy of the CT103A,a self-developed BCMA-targeting CAR construct against BCMA,in patients with AQP4-IgG seropositive NMOSD,an ongoing,investigator-initiated,open-label,single-arm,phase 1 clinical trial is conducted at our center.In total,12 patients were administered with a CAR-BCMA infusion.Ten of the 12 patients dosed were women(83.3%),with a median age of 49.5 years(range,30-67).were The most common events of grade 3 or higher were hematologic toxic effects.Seven patients(58%)developed infections,but no grade 4 infections occurred.Cytokine release syndrome was reported in all patients with only events of grade 1 or 2 observed.During the follow-up of a median 5.5 months,11 patients had no relapse;all patients generally reported improvement in disabilities and quality-of-life outcomes;11 patients’AQP-4 antibodies in serum showed a downward trend by the cutoff date.CAR T-cell expansion was associated with responses,and persisted more than 6 months post-infusion in 17%of the patients.In summary,CAR T-cell therapy shows a manageable safety profile and therapeutic potentials for patients with relapsed/refractory AQP4-IgG seropositive NMOSD.Another expansion phase is currently underway to determine the safety and efficacy of CAR T-BCMA infusion in patients with other neuro-inflammatory diseases.

Unfused-ring Acceptors with Dithienobenzotriazole Core for Efficient Organic Solar Cells

In recent years, non-fullerene acceptors(NFAs) with unfused-ring structure have received extensive attention due to their flexible combination of building blocks and relatively simple synthetic routes. In this work, three new A-D-C-D-A type unfused-ring acceptors(UFAs),named DTBTz EH-IC2F, DTBTz Me-IC2F and DTBTz Me-IC2Cl, were designed and synthesized with dithienobenzotriazole(DTBTz) as the core.Through modification of alkyl chain on the DTBTz unit and change of halogen atoms on the cyanoindanone end groups, the differences in optoelectronic properties of these three small molecule acceptors were investigated. The results show that changes in alkyl chain and halogen atom endow UFAs with different features, including shift in absorption, changes in energy level and molecular packing. When blended with donor PBDB-T, the organic solar cell based on DTBTz Me-IC2Cl achieves the highest device efficiency of 12.3%, while DTBTz EH-IC2F-based device obtains 11.5% efficiency and DTBTz Me-IC2F-based device obtains 12.0% efficiency. The stability tests show that all the devices obtain good efficiency retention rates. These results demonstrate that the introduction of a rigid aromatic ring DTBTz as an intermediate core not only effectively results in highly planar A-D-C-D-A small molecules, but also provides a new reference for the design and development of UFAs in OSCs.