地方医学高校以人为本的开放实验室研究探索

从以人为本的教学理念出发,提出了开设地方医学院校化学开放实验室,以培养学生的综合素质和创新能力为目标,满足不同层次学生需求,构建了以“学生为中心、创新能力为主线、自主学习、多元化评价体系”为核心的开放实验室教学观念。探讨了医学类院校采取开放实验室的意义,并利用开放实验室的教学经验对实验教学提供一定的借鉴意义,以期提高高校的实验教学质量。     

Molecular mechanics calculations on carbonyl compounds. II. Open‐chain ketones

Open‐chain aliphatic ketones were studied with the molecular mechanics (MM4) force field. A total of seven compounds were examined. Structures were well fit, including moments of inertia. Rotational barriers, vibrational spectra, and dipole moments were also well fit. The overall root mean square errors for MM3 and MM4 were 0.27 and 0.18%, respectively, for the six moments of inertia (known experimentally for two compounds) and 31 and 20 cm^?1, respectively, for the vibrational frequencies (over 99 weighted modes). © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 1426–1450, 2001     

Efficient calculation of open quantum system dynamics and time‐resolved spectroscopy with distributed memory HEOM (DM‐HEOM)

Time‐ and frequency‐resolved optical signals provide insights into the properties of light‐harvesting molecular complexes, including excitation energies, dipole strengths and orientations, as well as in the exciton energy flow through the complex. The hierarchical equations of motion (HEOM) provide a unifying theory, which allows one to study the combined effects of system‐environment dissipation and non‐Markovian memory without making restrictive assumptions about weak or strong couplings or separability of vibrational and electronic degrees of freedom. With increasing system size the exact solution of the open quantum system dynamics requires memory and compute resources beyond a single compute node. To overcome this barrier, we developed a scalable variant of HEOM. Our distributed memory HEOM, DM‐HEOM, is a universal tool for open quantum system dynamics. It is used to accurately compute all experimentally accessible time‐ and frequency‐resolved processes in light‐harvesting molecular complexes with arbitrary system‐environment couplings for a wide range of temperatures and complex sizes. © 2018 Wiley Periodicals, Inc.     

A computational study of unique properties of pillar[n]quinones: self-assembly to tubular structures and potential applications as electron acceptors and anion recognizers

Density functional theory has been used to calculate the thermodynamic properties and molecular orbitals of pillar[n]quinones. Pillar[n]quinones are expected to be effective electron acceptors and the ability to accept more than one electron increases with the size of the interior cavity. Pillar[5]quinone and pillar[7]quinone show a great intramolecular charge transfer upon the electron excitation from highest occupied molecular orbital (HOMO) to lowest unoccupied molecular orbital (LUMO) as indicated by a large difference of electron distributions between their HOMO and LUMO and a notable dipole moment difference between the ground and first triplet excited state. The aggregation of pillar[n]quinones leads to tubular dimeric structures joined by 2n C? H···O nonclassical hydrogen bonds (HBs) with binding energies about 2 kcal/mol per HB. The longitudinal extension of the supramolecular self‐assembly of pillar[n]quinone may be adjustable through forming and breaking their HBs by controlling the surrounding environment. The tunability of the diameter of the tubular structures can be achieved by changing the number of quinone units in the pillar[n]quinone. The electrostatic potential maps of pillar[n]quinones indicate that the positive charge in the interior cavity decreases as the number of quinone units increases. Chloride and bromide anions are chosen to examine the noncovalent anion‐π interactions between pillar[n]quinones and captured anions. The calculations show that the better compatibility of the effective radius of the anions with the interior dimension of pillar[n]quinone leads to larger stabilization energy. The selectivity of spatial matching and specific interaction of pillar[n]quinone is believed to possibly serve as a candidate for ionic and molecular recognition. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011     

Applying magnetic soft mold imprint technology with ultraviolet light‐emitting‐diode array on the fabrication of microlens arrays

This study proposed a novel technology, which uses exposed technology with ultraviolet light‐emitting‐diode (UV‐LED) arrays and the polydimethylsiloxane (PDMS) magnetic flexible soft mold imprint technology, to develop exposed equipments with UV‐LED arrays. This study used magnetic soft mold imprint technology to replicate the structure of microlens, providing a more effective alternative for imprint technology and application. The measurement results showed that PDMS with magnetic iron powder can precisely cast mold to replicate the structures of microlens. Electromagnetic plates were used to control even imprinting with magnetic force, in order to fill the mold of micro‐structure of the photo‐resist. Magnetic iron powder was added to PDMS to produce composite material, which can effectively avoid the transformation of pure PDMS during soft mold imprinting, and increase mechanical strength. Magnetic PDMS soft mold is easy to make, and the casting time is short, so that costs can be effectively reduced. Also with advantages of less free energy on its surface, and unlikely to adhere to the photo‐resist during imprinting, it can be combined with electromagnetic plates evenly to control the magnetic soft mold. This imprinting technology is a big advantage to the production process of micro‐structures during imprinting. Copyright © 2009 John Wiley & Sons, Ltd.     

Separation of mixtures of solvents with wide bore capillary columns connected in series

The gas chromatographic separation of the components of a complex mixture of industrial solvents, not possible on a single stationary phase owing to coelution of some of the compounds, has been achieved on two serially connected wide bore capillary columns of different polarity. The analysis of a mixture of twenty five compounds was optimized using the serial gas chromatography theory of Purnell and Williams. The capacity factors of sample components measured with the two columns coupled in series were found to agree with those predicted by theory, regardless of the order in which they were connected.     

Mechanistic Aspects of Carbon Nanotube Nucleation and Growth

The discovery, synthesis, characterization, and applicability of carbon nanotubes have produced tremendous excitement and interest among scientists and engineers. In particular, the use of these unique tubular nanostructures for new strong lightweight materials, nanoelectronics, fuel storage and cells, electron emitters and bio, scanning probe microscopy, and chemical sensing devices has created an intense effort to advance the synthesis so as to mass produce carbon nanotubes with control over diameter and helicity. The massive and controlled synthesis of this heralded nanostructure has been a great challenge. Although significant progress has advanced the preparation, more synthetic development is required. The syntheses have so far involved three main approaches: arc discharge vaporization, laser vaporization, and catalytic chemical vapor deposition. The synthetic trend has progressed to a point where further advancement with these techniques will require a better understanding of the mechanism of nucleation and growth. The mechanics of carbon nanotube nucleation and growth involve very complex and diverse phenomena occurring under extreme conditions and on the mesoscopic scale. As yet the detail mechanism is unknown. Difficulties with experimental probing and computational simulation have increased the mystery of this mechanism. This review presents an account of research on the synthesis of carbon nanotubes and the mechanism of formation. This overview includes all three mentioned synthetic approaches and hybrids thereof. On the basis of this broad account a comprehensive mechanism for carbon nanotube nucleation and growth naturally arises. This mechanism is qualitative and it hopes to inspire more quantitative exploration and synthetic advancement.     

Surface Charge‐Reversible Tubular Micromotors for Extraction of Nucleic Acids in Microsystems

Extraction of nucleic acids in microsystems is of significance for biomedical applications, but the current extraction methods generally require sophisticated microchannels and external equipment, hindering their practical applications. In this work, we have demonstrated a simple, versatile and efficient approach to extract nucleic acids in microsystems by developing cationic branched polyethyleneimine (PEI)‐functionalized tubular micromotors. The as‐developed tubular micromotors are fabricated by a two‐step process combining the template‐assisted electrodeposition and carbodiimide chemistry, and contain an inner catalytic Pt layer, a middle magnetic Ni layer and an outer cationic PEI layer. They exhibit autonomous bubble‐propelled motion in aqueous hydrogen peroxide solutions, which can be guided by an external magnetic field, and the surface charges can be reversibly modulated by changing the pH value of the solution. Consequently, the as‐developed tubular micromotors can selectively absorb nucleic acids from acidic solutions and desorb them into alkaline solutions, leading to the extraction of nucleic acids with high efficiency without external stirring. Furthermore, they can be operated in a microchannel chip without the aid of a pumping system. Our results indicate that this PEI‐functionalized tubular micromotor platform provides a novel, simple and versatile microsystem nucleic acid extraction technology, holding considerable promise for important practical applications.     

肾小管上皮细胞损伤及其诱导草酸钙晶体成核

肾上皮细胞损伤可促进肾结石形成.本文采用过氧化氢(H2O2)对人类肾小管上皮细胞(HKC)进行了氧化损伤,采用扫描电子显微镜(SEM)、X射线衍射分析(XRD)和倒置显微镜观察了HKC损伤前后的形态变化及其调控草酸钙(CaOxa)晶体成核、生长的差异;采用zeta电位分析仪检测了损伤前后HKC表面的zeta电位变化.结果表明,H2O2能明显地损伤HKC,降低细胞活性,且在H2O2浓度范围0.1～0.5mmol/L、作用时间0.5～1.5h内具有明显的剂量和时间的依赖性;使用0.5mmol/LH2O2作用1.5h可使HKC损伤达到饱和状态.HKC损伤程度增加后,其诱导的晶体数量显著增加,但晶体尺寸增加不明显(P0.05),表明损伤细胞诱导尿石症形成主要是增加晶体的成核位点而非促进晶体的生长.本文所建立的HKC氧化损伤的模型有助于进一步阐明CaOxa结石形成的细胞机制.