Search

The upgrade project of the Beijing Electron Positron Collider (BEPCII) is a high-current electron–positron collider with beam intensity close to 1A. The RF system plays an important role in providing energy for the beam, compressing the beam length and maintaining beam lifetime. Once the RF system shuts down the RF power for various reasons, the accelerator will stop working. In order to determine which reason causes the RF trip, a new RF trip diagnostic system was built based on the NI PXI system. The new RF trip diagnostic system is used to collect the data of the forward power, reflected power, cavity voltage, and beam current in a period of time before and after the RF trip event happens. The system uses LabVIEW as the control software, which conducts I/Q sampling of down-converted RF signals directly, then calculates the amplitude and phase of each RF signal, and plots the change curve. The data and figures are stored in the disk and MySQL database. The change curve can be replotted by the data browser which developed by the Python or PHP language. Through the analysis of the RF trip data and figures that produced by the new RF trip system, it can be clear whether the RF trip is caused by the RF system, so as to locate the reason of the RF trip more quickly and improve the reliability and stability of the machine operation.

Development of candidate cancer treatments is a resource-intensive process, with the research community continuing to investigate options beyond static genomic characterization. Toward this goal, we have established the genomic landscapes of 536 patient-derived xenograft (PDX) models across 25 cancer types, together with mutation, copy number, fusion, transcriptomic profiles, and NCI-MATCH arms. Compared with human tumors, PDXs typically have higher purity and fit to investigate dynamic driver events and molecular properties via multiple time points from same case PDXs. Here, we report on dynamic genomic landscapes and pharmacogenomic associations, including associations between activating oncogenic events and drugs, correlations between whole-genome duplications and subclone events, and the potential PDX models for NCI-MATCH trials. Lastly, we provide a web portal having comprehensive pan-cancer PDX genomic profiles and source code to facilitate identification of more druggable events and further insights into PDXs’ recapitulation of human tumors., Patient-derived xenograft models (PDX) have been extensively used to study the molecular and clinical features of cancers. Here the authors present a cohort of 536 PDX models from 25 cancers, as well as their genomic and evolutionary profiles and their suitability for clinical trials.

A digital low level radio frequency (DLLRF) system has been developed to replace the old analog LLRF and operated stably at BEPCII east RF station in the past two years. The RF stabilities required for BEPCII are ± 1% in magnitude and ± 1 degree in phase. These are satisfied both by the new DLLRF and the old analog LLRF. Yet, the DLLRF did not improve the RF stabilities so much as expected, especially when the beam current was high in collision mode. The purpose is to improve the RF stabilities further and meet the requirements by the upgraded BEPCII project (BEPC3). A disturbance observer based (DOB) controller to suppress the noise was developed and tested with beam at BEPCII RF system. The DOB controller works and the RF stabilities with beam may be improved from ± 1% to less than ± 0.5% in magnitude and from ± 1 degree to less than ± 0.5 degrees in phase.