Cleaved Iron Oxide Nanoparticles as T2 Contrast Agents for Magnetic Resonance Imaging

Iron oxide nanoparticles as contrast agents are reported to effectively improve magnetic resonance imaging of tissues and cells. In this work, cleaved iron oxide nanoparticles (CIONPs) were generated from hydrophobic FeO nanoparticles (HIONPs) by coating their surfaces with PEG‐phospholipids, oxidizing them under water, and slowly removing the residual FeO phase in phthalate buffer. The synthesized CIONPs showed good r₂ values of up to 258 s^?1 mM ^?1. Thus, the CIONPs can be employed as vectors for drug delivery due to their unique structure with an empty inner space, which enables their use in a wide range of applications.     

Darstellung,Eigenschaften und Kristallstruktur von Bis(phthalocyaninato)cer(IV)

Preparation, Properties and Crystal Structure of Bis(phthalocyaninato)cerium(IV) The anodic or chemical oxidation with dibenzoylperoxide of solutions of bis(phthalocyaninato)cerate(III) in dichloromethane yields selectively sparely soluble bis(phthalocyaninato)cerium(IV), [Ce(Pc(2-)) 2 ]. Green, monoclinic needles cristallize with a = 18.783(12) Å b = 18.739(16) Å c= 15.618(10) Å ß114.30(7)°; Z = 4; space group C2/c. [Ce(Pc(2–)) 2 ] is a sandwich complex in which the cerium Atom is eightfold coordinated by the isoindole nitrogens of the two staggered convex Pc-rings. The u.v.-vis., m.i.r., f.i.r. and resonance Raman spectra are consistent with the structure.     

四苯硼钠-甲苯胺蓝缔合物纳米微粒体系减色效应研究

在PH4.0醋酸-醋酸钠介质中，甲苯胺蓝在600nm处有一个吸收峰，随着四苯硼钠浓度的增大甲苯胺蓝在600nm处吸收峰降低，颜色减弱，这是由于甲苯胺蓝-四苯硼钠缔合物分子间存在较强的疏水作用及分子间作用力，聚集形成纳米微粒所致，甲苯胺蓝-四苯硼钠纳米微粒体系亦在600mm处有1个吸收峰，在400mm、470mm和580mm处产生3共振散射峰，其中400mm和580mm为甲苯胺蓝-四苯硼钠复合纳米微粒产生的特征共振散射峰，这也表明有纳米微粒存在，丙酮浓度的影响实验结果等表明，纳米微粒的形成是产生其减色效应的原因。     

染料分子对硫纳米微粒共振散射光谱的影响

在聚丙烯酰胺存在下液相硫纳米微粒在 470nm处产生 1个强共振散射峰 ;在可见光范围内无吸收峰且吸收值较小。硫微粒质量浓度在 0 0 5～ 1 0mg/L范围内与I4 70nm间有良好线性关系。研究了乙醇、丙酮 ,以及溴酚蓝、溴甲基紫、结晶紫、亮绿等有机染料对硫纳米微粒共振散射的影响。结果发现 ,染料分子吸收是产生共振散射峰的一个重要原因 ;随着染料分子非辐射吸收值的增大 ,硫纳米微粒共振散射光强度降低。实验证明 ,溴酚蓝浓度在 0～ 1 0× 10 -5mol/L范围内 ,在溴酚蓝最大吸收波长 5 90nm处的ΔI590nm与溴酚蓝浓度呈线性关系。     

Pulsed field gradient NMR on polybutylcyanoacrylate nanocapsules

The applicability of pulsed field gradient nuclear magnetic resonance spectroscopy to nanocapsule systems is demonstrated on dispersed poly-n-butylcyanoacrylate nanocapsules as a model system. Spectroscopic data are presented that allow for the structural characterization of the inner cavities, the observation of Brownian motion of the capsules and the detection of rapid molecular exchange through the capsule walls. An analytical formula is proposed that yields equilibrium populations and average residence times of a given tracer molecule, thus leading to crucial information regarding the permeability of the capsule walls. Based on these analytical methods, two varieties of nanocapsules are compared that derive from two different preparation procedures. It is found that thinner capsule walls obtained under acidic conditions of the organic phase during interfacial polymerization lead to correspondingly higher exchange rates of benzene as a tracer molecule.     

Generalized criterion of solvent polarity as a tool for control of chromatographic process

The generalized (reductive) criterion of solvent polarity was obtained by the method of multiparametric optimization of the Snyder index P", Hildebrand parameter _T , permittivity _r , and solvatochromism parameter E _T (30). Possibilities of employing this criterion for estimation of the elution power of normal and reversed mobile phases used in high-performance liquid chromatography were considered.     

Theoretical Studies on Formation Mechanism of Resonance States for Na＋I2→Na^＋ ＋I2^－ System

An extended linear combination of arrangement channels-scattering wave-function(LCAC-SW) quantum scattering dynamic method combined with ab initio quantum chemical calculation was used to study the forma-tion mechanism of the resonance states for the collinear Na I2→Na^ I2^- I^2- ion-pair formation process on At-en-Lanting-Los potential energy surface. The resonance energy and the resonance width or the lifetime for the first resonance peak were calculated. The resonance can be identified as the Feshbach type and the physi-cal interpretation is given. The geometric structure of the resonance state for the title system has been opti-mized.