Stereospecific Electrophilic Fluorination of Alkylcarbastannatrane Reagents

The introduction of fluorine atoms into organic molecules significantly changes their physical, chemical, and biological properties. Fluorinated organic compounds are used as pharmaceuticals, agrochemicals, materials, and tracers for positron emission tomography (PET). For example, the site-specific fluorination of drugs can block sites of phase I metabolism by cytochrome P450 enzymes as well as improve target-binding affinities. In view of the unique features of fluorine-containing compounds, there has been increasing interest in the development of novel methods for the synthesis of fluorinated molecules, especially the site-specific monofluorination of complex molecules. Herein, we present the enantiospecific conversion of chiral secondary alkylcarbastannatranes into alkylfluorides. Carbastannatranes were used as nucleophiles, with Selectfluor I as the electrophilic fluorinating agent, to afford alkylfluorides in short reaction times. The addition of styrene as a radical trap was found to enhance enantiospecificity. A broad range of alkylcarbastannatranes were converted into alkylfluorides under mild condition by this method. Other halogenations, such as chlorination, bromination and iodination, were also applied to alkylcarbastannatranes with high enantiospecificity

HSIC Regularized LTSA

Hilbert-Schmidt Independence Criterion (HSIC) measures statistical independence between two random variables. However, instead of measuring the statistical independence between two random variables directly, HSIC first transforms two random variables into two Reproducing Kernel Hilbert Spaces (RKHS) respectively and then measures the kernelled random variables by using Hilbert-Schmidt (HS) operators between the two RKHS. Since HSIC was first proposed around 2005, HSIC has found wide applications in machine learning. In this paper, a HSIC regularized Local Tangent Space Alignment algorithm (HSIC-LTSA) is proposed. LTSA is a well-known dimensionality reduction algorithm for local homeomorphism preservation. In HSIC-LTSA, behind the objective function of LTSA, HSIC between high-dimensional and dimension-reduced data is added as a regularization term. The proposed HSIC-LTSA has two contributions. First, HSIC-LTSA implements local homeomorphism preservation and global statistical correlation during dimensionality reduction. Secondly, HSIC-LTSA proposes a new way to apply HSIC: HSIC is used as a regularization term to be added to other machine learning algorithms. The experimental results presented in this paper show that HSIC-LTSA can achieve better performance than the original LTSA

gem-Dibromocyclopropanes and enzymatically derived cis-1,2-dihydrocatechols as building blocks in alkaloid synthesis

The application of the title building blocks, the 6,6-dibromobicyclo[3.1.0]hexanes and the cis-1,2-dihydrocatechols, to the total synthesis of crinine and lycorinine alkaloids is described.We thank the Australian Research Council and the Institute of Advanced Studies for generous financial support

Manipulating the enone moiety of levoglucosenone: 1,3-Transposition reactions including ones leading to isolevoglucosenone

This research was part-funded by Circa Group Pty Ltd

Effectiveness of Online Mindfulness-Based Interventions on Psychological Distress and the Mediating Role of Emotion Regulation

Online mindfulness-based intervention as a feasible and acceptable approach has received mounting attention in recent years, yet more evidence is needed to demonstrate its effectiveness. The primary objective of this study was to examine the effects of online mindfulness-based programs on psychological distress (depression and anxiety). The randomized controlled intervention design consisted of four conditions: group mindfulness-based intervention (GMBI), self-direct mindfulness-based intervention (SDMBI), discussion group (DG) and blank control group (BCG). The program lasted 8 weeks and a total of 76 participants completed the pre- and post-test. Results showed that participants in GMBI and SDMBI had significant pre- and post-test differences on mindfulness, emotion regulation difficulties, and psychological distress, with medium to large effect sizes. In addition, ANCOVA results indicated significant effects of group membership on post-test scores of mindfulness, depression and anxiety when controlling the pretest scores, with medium to large effect sizes. The GMBI appeared to exert the greatest effects on outcome variables in comparison with other groups. In addition, changes in emotion regulation difficulties across groups could mediate the relationship between changes in mindfulness dimensions (Observing and Describing) and changes in psychological distress across groups. These results provided encouraging evidence for the effectiveness of online mindfulness-based interventions in reducing psychological distress, and the possible mediating role of emotion regulation, while also underlining the importance of group discussion in online mindfulness-based interventions

Protective Effects of Lycium barbarum

To observe the effects of Lycium barbarum polysaccharides (LBP) on testis spermatogenic injuries induced by Bisphenol A (BPA) in mice. BPA was subcutaneously injected into mice at a dose of 20 mg/kg body weight (BW) for 7 consecutive days. LBP was administered simultaneously with BPA by gavage daily at the dose of 50, 100, and 200 mg/kg BW for 7 days. After treatment, the weight and the histopathology changes of testis and epididymis were examined; the contents of T, LH, GnRH, antioxidant enzyme, and malondialdehyde (MDA) in serum were detected; proapoptotic protein Bax and antiapoptotic protein Bcl-2 were also detected by immunohistochemical method. Results showed that the weights of testis and epididymis were all increased after supplement with different dosages of LBP compared with BPA group, and the activities of SOD and GSH-Px were significantly increased in LBP groups, while MDA contents were gradually decreased. Moreover, the levels of T, LH, and GnRH were significantly elevated in serum treated with 100 mg/kg LBP. LBP also shows significant positive effects on the expression of Bcl-2/Bax in BPA treated mice. It is concluded that LBP may be one of the potential ingredients protecting the adult male animals from BPA induced reproductive damage

UC-Secure Source Routing Protocol

The multi-path routing scheme provides reliable guarantee for mobile ad hoc network. A new method is proposed that is using to analyze the security of multi-path routing protocol within the framework of Universally Composable (UC) security. Based on the topological model that there exist adversarial nodes, the concept of plausible route is extended and the definition of plausible-route set is presented. Plausible-route set is used in description of the multi-path routing for Ad hoc network, and a formal security definition based on UC-RP is given. A provably Security Multiple Node-Disjoint Paths source routing (SMNDP) is proposed and address secure fault issue of MNDP in the active adversary model. The new approach shows that the security of SMNDP can be reduced to the security of the message authentication code and the digital signature. SMNDP implements the correctness of route discovery process, the authentication of nodes identifier and the integrality of route information

mTORC1 controls lysosomal Ca²⁺ release through the two-pore channel TPC2

The ion channel TPC2 is required for Ca 2+ mobilization from lysosomes in response to mTORC1 inhibition and to NAADP. </jats:p