化学科研基础与创新实验课程建设的探索与实践

大学生的科研能力训练和创新能力培养是大学本科教学的核心问题之一。化学实验教学是实现全面化学教育最有效的形式,对学生科研素质和创新能力的培养至关重要。课程团队将本院科研与实验教学有机结合,提升了实验教学梯度和深度。本文主要从课程定位与目标、课程团队建设、课程内容建设、课程实施与评价等方面介绍课程建设情况。经过近十年的探索与实践,该课外科研实验课程教学在人才培养、教改和科研等方面均取得了不错的成效,有效地促进了实验课程改革。同时,针对课程中的不足,本文提出进一步的改进方向与措施,并对未来做出展望。

T cell-depleting nanoparticles ameliorate bone loss by reducing activated T cells and regulating the Treg/Th17 balance

Estrogen deficiency is one of the most frequent causes of osteoporosis in postmenopausal women.Under chronic inflammatory conditions caused by estrogen deficiency,activated T cells contribute to elevated levels of proinflammatory cytokines,impaired osteogenic differentiation capabilities of bone marrow mesenchymal stem cells(BMMSCs),and disturbed regulatory T cell(Treg)/Th17 cell balance.However,therapeutic strategies that re-establish immune homeostasis in this disorder have not been well developed.Here,we produced T cell-depleting nanoparticles(TDNs)that ameliorated the osteopenia phenotype and rescued the osteogenic deficiency of BMMSCs in ovariectomized(OVX)mice.TDNs consist of monocyte chemotactic protein-1(MCP-1)-encapsulated mesoporous silica nanoparticles as the core and Fas-ligand(FasL)as the corona.We showed that the delicate design of the TDNs enables rapid release of MCP-1 to recruit activated T cells and then induces their apoptosis through the conjugated FasL both in vitro and in vivo.Apoptotic signals recognized by macrophages help skew the Treg/Th17 cell balance and create an immune tolerant state,further attenuating the osteogenic deficiency of BMMSCs and the osteopenia phenotype.Mechanistically,we found that the therapeutic effects of TDNs were partially mediated by apoptotic T cell-derived extracellular vesicles(ApoEVs),which promoted macrophage transformation towards the M2 phenotype.These findings demonstrate that TDNs may represent a promising strategy for treating osteoporosis and other immune disorders.

Synthesis and Characterization of Osmium Polycyclic Aromatic Complexes via Nucleophilic Reactions of Osmapentalyne

Treatment of osmapentalyne [Os { ≡C-C（COOMe）=CH-C =CH-C（PPh3） =CH-}Cl（PPh3）2]＋ BF4-with arylamines in the presence of Cs2CO3 produced osmium-bridged polycyclic aromatic complexes.In this reaction,metal carbyne of osmapentalyne was first attacked by nucleophiles,followed by a C-H oxidative addition.The UV-Vis spectra of these osmium-bridged polycyclic aromatic complexes were measured.The result shows that these osmium-bridged polycyclic aromatic complexes have broad absorption in the UV-Vis region up to 650 nm.

The S190R mutation in the hemagglutinin protein of pandemic H1N1 2009 influenza virus increased its pathogenicity in mice

Human influenza viruses preferentially bind to sialic acid-α2,6-galactose (SAα2,6Gal) receptors, which are predominant in human upper respiratory epithelia, whereas avian influenza viruses preferentially bind to SAα2,3Gal receptors. However, variants with amino acid substitutions around the receptor-binding sites of the hemagglutinin (HA) protein can be selected after several passages of human influenza viruses from patients’ respiratory samples in the allantoic cavities of embryonated chicken eggs. In this study, we detected an egg-adapted HA S190R mutation in the pandemic H1N1 virus 2009 (pdmH1N1), and evaluated the effects of this mutation on receptor binding affinity and pathogenicity in mice. Our results revealed that residue 190 is located within the pocket structure of the receptor binding site. The single mutation to arginine at position 190 slightly increased the binding affinity of the virus to the avian receptor and decreased its binding to the long human α2,6-linked sialic acid receptor. Our study demonstrated that the S190R mutation resulted in earlier death and higher weight loss in mice compared with the wild-type virus. Higher viral titers at 1 dpi (days post infection) and diffuse damage at 4 dpi were observed in the lung tissues of mice infected with the mutant virus.

Carbolong Chemistry: Planar CCCCX-Type (X = N, O, S) Pentadentate Chelates by Formal [3+1] Cycloadditions of Metalla-Azirines with Terminal Alkynes

Three-membered unsaturated rings have been widely utilized in organic synthesis due to their inherent highly strained structures.Although much research has been applied to ring-expansion reactions of such strained ring systems,pathways other than[3+2]cycloadditions have rarely been observed in their reactions with alkynes,and to date,no[3+1]cycloadditions of isolated three-membered unsaturated rings with alkynes have been reported.Here we demonstrate an unprecedented[3+1]cycloaddition in which a fused metalla-azirine is used as a template to generate a series of planar CCCCX-type(X=N,O,S)pentadentate carbolong complexes 3–6.A series of substituted alkynes was tested for further exploration of the scope and mechanism for the[3+1]cycloaddition reactions.Complexes 3–6 represent rare examples of planar pentadentate complexes that assemble fourπ-conjugated fused rings by one bridgehead atom.These novel complexes are thermally stable in air and absorb ultraviolet,visible,and near-infrared light,and thus are potentially applicable in photoelectric devices and pharmaceuticals.

Joint parameter and state estimation for stochastic uncertain system with multivariate skew t noises

Due to the pulse interference, measurement outliers and artificial modeling errors, the multivariate skew t noise widely exists in the real environment. However, to date, little attention has been paid to the state estimation for systems in which the process noise and the measurement noise are both modeled as the heavy-tailed and skew non-Gaussian noise. In this paper, the multivariate skew t distribution is utilized to model the heavy-tailed and skew non-Gaussian noise. Then a probabilistic graphical form of the multivariate skew t distribution is given and proved. Based on the probabilistic graphical form, a hierarchical Gaussian state space model for stochastic uncertain systems is proposed, which transforms the estimation problem for systems with the heavy-tailed and skew non-Gaussian noises into the one with a hierarchical Gaussian state space model. Next, given the designed Gaussian state space model, the robust Bayesian filter and smoother based on the variational Bayesian inference are proposed to approximately estimate the system state and the unknown noise parameters. Furthermore, the complexity analysis together with the controllability and observability for stochastic uncertain systems with multivariate skew t noises is given. Finally,the simulation results of the target tracking scenario verify the validity of the proposed algorithms.