Hovendulcisic acid A-D: four novel ceanothane-type triterpenoids from Hovenia dulcis stems with anticancer properties

Sixteen ceanothane-type triterpenoids, including four new compounds—hovendulcisic acids A–D (1–4) —were purified from the stems of Hovenia dulcis Thunb. The structures of 1–4 were confirmed by comprehensive means including ECD and quantum chemical calculations. Putative biosynthetic pathways of 1–16 were proposed, and 3, 5, and 15 exhibited antitumor activity on A549 and MDA-MB-231 cells

Mitogenome characterization and diversity of the nangqian grey yak (bos grunniens)

Nangqian grey yak (Bos grunniens) is a unique yak population in Qinghai Province, China. In this study, the whole mitogenome sequences of 18 Nangqian grey yaks were sequenced based on the next-generation sequencing (NGS) technology and annotated. The total length of whole mitogenome sequence is between 16.323 bp and 16.325 bp, including a non-coding control region (D-loop region), 22 tRNA genes, 13 protein-coding genes and two rRNA genes (12S rRNA and 16S rRNA). Maternal genetic diversity based on the mitogenome variations was analyzed. A total of 12 haplotypes were identified among 18 complete mitogenome sequences, the haplotype diversity and nucleotide diversity of Nangqian grey yak were 0.948±0.033 and 0.001±0.001, respectively. Compared with the wild yak population and six other domestic yak breeds/populations in China, the haplotype diversity of Nangqian grey yak population was higher, indicating abundant maternal genetic diversity in Nangqian grey yak. The phylogenetic tree showed that Nangqian grey yak was most closely related to Tibet alpine, Xueduo, Changtai, Sibu, Zhongdian, Tianzhu white, Ashdan, Jinchuan, Jiulong, Pamir, Pali, Qinghai plateau, Huanhu, Datong, Bazhou and wild yak breeds/populations, closer to Chawula, Muli, Gannan, Niangya and Yushu yak breeds, but far away from other yak breeds (i.e. Leiwuqi and Maiwa yak)

The 3rd Anti-UAV Workshop & Challenge: Methods and Results

The 3rd Anti-UAV Workshop & Challenge aims to encourage research in developing novel and accurate methods for multi-scale object tracking. The Anti-UAV dataset used for the Anti-UAV Challenge has been publicly released. There are two main differences between this year's competition and the previous two. First, we have expanded the existing dataset, and for the first time, released a training set so that participants can focus on improving their models. Second, we set up two tracks for the first time, i.e., Anti-UAV Tracking and Anti-UAV Detection & Tracking. Around 76 participating teams from the globe competed in the 3rd Anti-UAV Challenge. In this paper, we provide a brief summary of the 3rd Anti-UAV Workshop & Challenge including brief introductions to the top three methods in each track. The submission leaderboard will be reopened for researchers that are interested in the Anti-UAV challenge. The benchmark dataset and other information can be found at: https://anti-uav.github.io/.Comment: Technical report for 3rd Anti-UAV Workshop and Challenge. arXiv admin note: text overlap with arXiv:2108.0990

The Bantam microRNA Is Associated with Drosophila Fragile X Mental Retardation Protein and Regulates the Fate of Germline Stem Cells

Fragile X syndrome, a common form of inherited mental retardation, is caused by the loss of fragile X mental retardation protein (FMRP). We have previously demonstrated that dFmr1, the Drosophila ortholog of the fragile X mental retardation 1 gene, plays a role in the proper maintenance of germline stem cells in Drosophila ovary; however, the molecular mechanism behind this remains elusive. In this study, we used an immunoprecipitation assay to reveal that specific microRNAs (miRNAs), particularly the bantam miRNA (bantam), are physically associated with dFmrp in ovary. We show that, like dFmr1, bantam is not only required for repressing primordial germ cell differentiation, it also functions as an extrinsic factor for germline stem cell maintenance. Furthermore, we find that bantam genetically interacts with dFmr1 to regulate the fate of germline stem cells. Collectively, our results support the notion that the FMRP-mediated translation pathway functions through specific miRNAs to control stem cell regulation

Video-assisted thoracoscopic right upper lobectomy in a patient with a right-sided aortic arch and Kommerell diverticulum

Abstract Background It is a very rare condition for a patient to have right lung cancer and a right-sided aortic arch simultaneously. Right lobectomy under video-assisted thoracoscopic surgery (VATS) in such a patient is a challenging procedure that is seldom reported. We successfully performed a VATS right upper lobectomy in a 77-year-old female with a right-sided aortic arch and Kommerell diverticulum. Case presentation A 77-year-old woman was referred to our division for a mixed ground-glass opacity lesion in the right upper lung. A right-sided aortic arch with Kommerell diverticulum was identified by preoperative 3D CT reconstruction. A VATS right upper lobectomy with radical mediastinal lymph node dissection was performed, and the final histological staging was Ia3 (pT1cN0M0). The patient was discharged without any complications. Conclusions We conclude that the video-assisted thoracic surgery can be safely performed in such conditions. It is difficult to determine the extent of upper mediastinal lymph node dissection in such cases

Prefixed-Threshold Real-Time Selection for Free-Space Sending-or-Not Twin-Field Quantum Key Distribution

As a variant of the twin-field quantum key distribution (TF-QKD), the sending-or-not twin-field quantum key distribution (SNS TF-QKD) is famous for its higher tolerance of misalignment error, in addition to the capacity of surpassing the rate–distance limit. Importantly, the free-space SNS TF-QKD will guarantee the security of the communications between mobile parties. In the paper, we first discuss the influence of atmospheric turbulence (AT) on the channel transmittance characterized by the probability distribution of the transmission coefficient (PDTC). Then, we present a method called prefixed-threshold real-time selection (P-RTS) to mitigate the interference of AT on the free-space SNS TF-QKD. The simulations of the free-space SNS TF-QKD with and without P-RTS are both given for comparison. The results showed that it is possible to share the secure key by using the free-space SNS TF-QKD. Simultaneously, the P-RTS method can make the free-space SNS TF-QKD achieve better and more stable performance at a short distance

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喹啉不对称氢化反应是不对称氢化研究的重点之一.其氢化产物四氢喹啉不仅是重要的有机合成中间体,同时也是自然界中生物碱的结构单元和生物活性化合物.周永贵研究组首次报道了手性（R）-MeO-Biphep/Ir体系成功用于喹啉的不对称催化,取得了非常好的反应结果.随后他们对喹啉底物进行了拓展,包括拥有特殊取代基的喹啉衍生物,均取得了良好的反应结果.后来多个研究组对该反应进行了深入研究并开发出了多个不同手性膦配体的Ir催化体系.虽然喹啉不对称氢化反应取得了很大的发展,但是该均相反应体系只能在高的反应催化剂用量下才能实现好的结果.进一步研究发现手性配体与金属Ir络合后形成反应活性物种,但后者可发生二聚或三聚,生成的产物是不具有催化活性的,从而导致了反应体系需要高的催化剂的用量.为此人们做了大量研究.范青华研究组通过对BINAP基团上嫁接大空间位阻的枝状分子合成了一系列新的手性BINAP配体,在与Ir络合后,表现出远高于均相催化剂的反应活性,且可循环利用.在该体系中,大位阻的枝状分子起到了阻隔活性物种二聚、三聚的作用,因而提高了反应活性.后来周永贵研究组也尝试通过改变有机配体的方法来实现高的反应活性.他们选择改变手性双膦配体上P原子所连接有机配体的空间位阻来实现对活性物种多聚的控制.实验同样取得了很好的反应效果.对于均相反应体系,我们只能通过这种改变有机配体空间位阻的方式来降低活性物种多聚的可能性,那么如何彻底阻止这种多聚呢？非均相体系给我们提供了很好的研究思路,但如何将非均相体系引入到喹啉不对称氢化反应体系当中成为了难点.共轭微孔聚合物（CMPs）的发展使得手性催化体系很容易从均相转变到非均相.这种材料具有较高的比表面积和固定的开放孔道结构,可应用于非均相催化中.且制备相对容易.我们可以将手性双膦配体作为材料制备配体嫁接到CMPs材料当中.在这种材料当中,手性配体会以有序、空间分离的方式分布,在与Ir配合后应用于喹啉不对称氢化反应中,从而从根本上避免了活性物种多聚的可能因此反应活性提高.我们曾首次成功合成了一系列含有手性（R）-Binap基团的共轭微孔聚合材料-BINAP-CMPs,并将其用于β-酮酸酯的不对称氢化反应当中,取得了很好的催化效果.手性BINAP基团均匀、有序地分散于该材料中.我们尝试利用BINAP-CMPs固有的空间隔离效应,将其应用于喹啉的不对称氢化反应中,结果表明,在相同条件下,非均相BINAP-CMPs/Ir催化体系的TOF值是340 h^–1,是均相BINAP/Ir体系（100 h^–1）3倍,反应的对映体选择性与均相相当;另外该催化体系多循环利用次后仍可以保持高的反应活性.我们还发现材料结构性质对反应结果的影响很大,材料的比表面积和孔容更大反应结果更好