ENANTIOSELECTIVE SYNTHESIS AND CYCLOISOMERIZATION OF 1-BICYCLO[1.1.0]BUTAN-1-YL ALKYLAMINES

This dissertation demonstrates the synthesis and application studies of 1-bicyclo[1.1.0]butyl alkylamines. The enantioselective synthesis of 1-bicyclo[1.1.0]butyl alkylamines was achieved by dicarbene addition to enantiomerically enriched propargyl amides. The enantioselective addition of alkynes to imines proceeded well for most N-DPP amides. But the carbene addition suffered from the formation of cyclopropane byproducts. However, a series of silyl-substituted bicyclo[1.1.0]butanes could be synthesized by this methodology in high, reproducible yields. When tethered to an activated alkyne, the silyl-substituted bicyclo[1.1.0]butane undergoes cyclization to form pyrrolidines. In the application of the 1-bicyclo[1.1.0]butyl alkylamines, a palladium(0)-catalyzed cycloisomerization of bicyclo[1.1.0]butanes and methylenecyclopropanes has been developed. 3-Azaspiro[bicyclo[3.1.0] hexane-6,1'-cyclopropane] is obtained with excellent stereoselectivity. Novel 2,3,3a,6a- tetrahydrocyclopenta[c]pyrrol-4(1H)-one is the product of the cycloisomerization and carbonylation sequence

Outage Performance Enhancement for NOMA Based Cooperative Relay Sharing Networks

This letter considers a non-orthogonal multiple access (NOMA) based cooperative relay sharing (CRS) network, where two sources communicate with their corresponding users over the same time and frequency via a shared decode-and-forward relay. A novel transmission scheme using max-min criterion based dynamic decoding order strategy is proposed to minimize the outage probability of the network at the cost of lower complexity and overhead. The closed-form expression of the overall outage probability for the proposed scheme is derived. Both analytical and simulation results show that the proposed scheme can achieve non-zero diversity order and almost the same outage performance as the dynamic power allocation based transmission scheme for NOMA based CRS networks

2.3 Å resolution cryo-EM structure of human p97 and mechanism of allosteric inhibition

p97 is a hexameric AAA ATPase that is an attractive target for cancer drug development. Here, we report cryo-EM structures for ADP-bound, full-length, hexameric wild-type p97 in the presence and absence of an allosteric inhibitor at resolutions of 2.3 Å and 2.4 Å, respectively. We also report cryo-EM structures at ~ 3.3 Å, 3.2 Å and 3.3 Å resolutions respectively, for three distinct, co-existing functional states of p97 with occupancies of 0, 1 or 2 molecules of ATPγS per protomer. A large corkscrew-like change in molecular architecture coupled with upward displacement of the N-domain is observed only when ATPγS is bound to both D1 and D2 domains. These cryo-EM structures establish the sequence of nucleotide-driven structural changes in p97 at atomic resolution. They also enable elucidation of the binding mode of an allosteric small molecule inhibitor to p97 and illustrate how inhibitor binding at the interface between D1 and D2 domains prevents propagation of the conformational changes necessary for p97 function

Genomic monitoring of SARS-CoV-2 uncovers an Nsp1 deletion variant that modulates type I interferon response

The SARS-CoV-2 virus, the causative agent of COVID-19, is undergoing constant mutation. Here, we utilized an integrative approach combining epidemiology, virus genome sequencing, clinical phenotyping, and experimental validation to locate mutations of clinical importance. We identified 35 recurrent variants, some of which are associated with clinical phenotypes related to severity. One variant, containing a deletion in the Nsp1-coding region (D500-532), was found in more than 20% of our sequenced samples and associates with higher RT-PCR cycle thresholds and lower serum IFN-beta levels of infected patients. Deletion variants in this locus were found in 37 countries worldwide, and viruses isolated from clinical samples or engineered by reverse genetics with related deletions in Nsp1 also induce lower IFN-beta responses in infected Calu-3 cells. Taken together, our virologic surveillance characterizes recurrent genetic diversity and identified mutations in Nsp1 of biological and clinical importance, which collectively may aid molecular diagnostics and drug design.Peer reviewe

Potential of Core-Collapse Supernova Neutrino Detection at JUNO

JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve

Detection of the Diffuse Supernova Neutrino Background with JUNO

As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO

Real-time Monitoring for the Next Core-Collapse Supernova in JUNO

Core-collapse supernova (CCSN) is one of the most energetic astrophysical events in the Universe. The early and prompt detection of neutrinos before (pre-SN) and during the SN burst is a unique opportunity to realize the multi-messenger observation of the CCSN events. In this work, we describe the monitoring concept and present the sensitivity of the system to the pre-SN and SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is a 20 kton liquid scintillator detector under construction in South China. The real-time monitoring system is designed with both the prompt monitors on the electronic board and online monitors at the data acquisition stage, in order to ensure both the alert speed and alert coverage of progenitor stars. By assuming a false alert rate of 1 per year, this monitoring system can be sensitive to the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos up to about 370 (360) kpc for a progenitor mass of 30$M_{\odot}$ for the case of normal (inverted) mass ordering. The pointing ability of the CCSN is evaluated by using the accumulated event anisotropy of the inverse beta decay interactions from pre-SN or SN neutrinos, which, along with the early alert, can play important roles for the followup multi-messenger observations of the next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure

Research and Design of a Routing Protocol in Large-Scale Wireless Sensor Networks

无线传感器网络，作为全球未来十大技术之一，集成了传感器技术、嵌入式计算技术、分布式信息处理和自组织网技术，可实时感知、采集、处理、传输网络分布区域内的各种信息数据，在军事国防、生物医疗、环境监测、抢险救灾、防恐反恐、危险区域远程控制等领域具有十分广阔的应用前景。 本文研究分析了无线传感器网络的已有路由协议，并针对大规模的无线传感器网络设计了一种树状路由协议，它根据节点地址信息来形成路由，从而简化了复杂繁冗的路由表查找和维护，节省了不必要的开销，提高了路由效率，实现了快速有效的数据传输。 为支持此路由协议本文提出了一种自适应动态地址分配算——ADAR（AdaptiveDynamicAddre...As one of the ten high technologies in the future, wireless sensor network, which is the integration of micro-sensors, embedded computing, modern network and Ad Hoc technologies, can apperceive, collect, process and transmit various information data within the region. It can be used in military defense, biomedical, environmental monitoring, disaster relief, counter-terrorism, remote control of haz...学位：工学硕士院系专业：信息科学与技术学院通信工程系_通信与信息系统学号：2332007115216

Neutrophil-to-Lymphocyte Ratio Is a Potential Prognostic Biomarker in Patients with Ovarian Cancer: A Meta-Analysis

Background and Aims. Plenty of studies were conducted to explore the prognostic significance of neutrophil-to-lymphocyte ratio (NLR) in ovarian cancer with contradictory results. This study aims to summarize the prognostic significance of NLR in patients with ovarian cancer. Methods. A literature search in PubMed, Cochrane Library, and Embase was conducted. The endpoints were progression-free survival (PFS) and overall survival (OS). Results. Eleven studies involving a total of 2,892 patients were identified. The results indicated that patients with high NLR had shorter PFS compared to patients with low NLR in ovarian cancer (HR = 1.55, 95% CI = 1.15–2.08, p=0.004, and I2=61%). Similarly, high NLR was related to shorter OS (HR = 1.51, 95% CI = 1.03–2.23, p=0.04, and I2=85%). Moreover, high NLR was significantly associated with shorter PFS when the NLR cut-off was less than 3.3 (p=0.03) or when treatment is operation (p=0.002). In addition, high NLR was distinctly related to worse OS in Asian people (p = 0.04) or operation (p = 0.04). Conclusion. High NLR was associated with shorter PFS and shorter OS in ovarian cancer. NLR is potentially a promising prognostic biomarker in patients with ovarian cancer