基于支持向量学习机方法的人体小肠吸收药物活性的预测

为了预测分子在人体小肠中的吸收,本文计算了表征分子的电子、拓扑、几何结构、分子形状等特征的102个分子描述符,用遗传算法变量选择方法使描述符减少到47个。体系共包含了230个化合物分子,69个不能被吸收(mA-),161个可以被吸收(HIA )。对建立的SVM模型,用5重交叉验证和独立测试集进行验证,预测正确率分别达到79．1％和77．1％,结果具有较好的一致性。在模型验证中,通过聚类分析方法组合训练集和测试集,保证了模型的稳定性,提高了建模效率。     

Preparation of new full UV-absorbing carbon dots from quercetin and their application in UV-absorbing systems for waterborne polyurethane coatings

In this paper, a kind of novel fully UV absorbing carbon dots (QC-CDs) were prepared as UV absorbers by a one-step hydrothermal method using quercetin as raw material. The prepared QC-CDs have high absorption efficiency (over 98%) in the whole ultraviolet region (200–400 nm), and are almost completely transmitted in the visible light region. The prepared QC-CDs have good stability and resistance to photobleaching. After the treatment with different pH and temperature, the QC-CDs maintained good absorption stability. QC-CDs have a wider UV absorption range than commercial water-soluble organic UV absorbers-BP-4. In terms of aging resistance, QC-CDs can achieve the same effect as BP-4. After subjecting QC-CDs and BP-4 to different pH values, it was found that QC-CDs remain fully UV absorbing at different pH conditions and maintain good absorption stability, but BP-4 loses its function as a UV absorber under alkaline conditions. Then, the UV absorption mechanism of QC-CDs has also been investigated and applied to the UV absorption systems of waterborne coatings PU. Finally, the QC-CDs@PU with full UV absorption properties was applied in the photodegradation prevention experiment of Rhodamine B. At present, the preparation process of QC-CDs is simple and environmentally friendly. QC-CDs have the potential to become a new generation of water-soluble UV absorbers.     

A Highly Efficient UV‐C Absorber Based on Theoretical and Experimental Studies

Based on two published UV absorbing molecules 2‐(5′‐tert‐butyl‐2′‐hydroxyl)benzotriazole (Tinuvin‐PS ) and hydroxybenzophenone (HBP ), both having characteristic absorption capability, a refined UV absorber, 2‐(3′‐benzoyl‐2′‐hydroxy‐5′‐tert‐butylphenyl)benzotriazole, has been synthesized. This new UV absorber exhibits a wider absorption range and better thermal stability compared to either Tinuvin‐PS and HBP and a higher absorption efficiency in the UV ‐C range. Theoretical studies reveal that the UV ‐C absorption arises from the electron density transfer from the Tinuvin‐PS moiety to the HBP moiety and the enhanced absorption efficiency is ascribed to the presence of the carbonyl's π system.     

UV and IR absorption spectra of C3 embedded in solid para-hydrogen

This paper presents the UV and IR absorption spectroscopy of small carbon molecules of C₃ observed using a high-resolution Fourier-transform spectrometer. The C₃ molecules were produced by irradiation of dimers or larger clusters of acetylene with an ArF laser (λ=193 nm). Sharp UV absorption features with multiple structures were observed in the electronic transition of C₃. The sharp UV absorption demonstrates the potential of solid para-hydrogen as a matrix for high-resolution spectroscopy of UV–vis electronic transitions.