Nanomaterials in Cerebrovascular Disease Diagnose and Treatment

Cerebrovascular diseases (CVDs) are among the most serious diseases with high mortality and disability rates. The prevalent diagnosis and treatment methods of CVDs include imaging and interventional therapy. With the development of nanotechnology, large numbers of nanomaterials have been applied to the diagnosis and treatment of CVDs, mainly including carbon nanotubes, quantum dots, fullerenes, and dendrimers. In this review, the applications of nanomaterials in the field of diagnosis and treatment of CVDs, mainly including drug target delivery, imaging, therapy, endovascular treatment, and angiogenesis, are summarized. The applications of nanomaterials in the field of CVD are almost in the laboratory, and more effort is needed for clinical translation. The aim of this review is to provide useful information for future research and equipment development.     

DSA、CTA联合MR影像评估AIS患者脑支循环及预后性关系

探讨数字减影血管成像(DSA)、计算机断层扫描血管成像(CTA)联合磁共振(MR)影像评估急性缺血性卒中(AIS)患者脑支循环及预后性关系。选取60例大脑中动脉M1段急性闭塞所致AIS患者为研究对象,根据DSA、CTA与MR影像对其脑侧支循环评估,比较患者基线资料、结局指标等,并分析预后性。结果发现:基于DSA、CTA与MR影像对AIS患者脑侧支循环评估结果一致性良好;3种影像模式下脑侧支循环良好组与不良组结局资料差异显著(P<0.05);多因素分析显示,FVH-ASPECTS评分、rLMC评分、ASITN/SIR分级量表均为AIS患者神经功能预后的独立影响因素。总之,DSA、CTA、MR影像对AIS患者脑侧支循环评估具有一致性,且FVH-ASPECTS评分、rLMC评分、ASITN/SIR分级量表均为AIS患者神经功能预后的独立影响因素。     

Synergistic Effects of Pseudocolor Imaging,Differentiation, and Square and Logarithmic Conversion on Accuracy of Quantification of Chemical Characteristics Using Test Strips and Similar Products

Test strips and similar products are highly feasible tools for the rapid and approximate determination of chemical characteristics. Although the application of both the quantitative observation of coloration and regression modeling has recently enabled these products to become quantitative tools, their precision and accuracy may be further improved. In this study, the pseudocolor imaging of the coloration image, derivative spectrophotometry-like differentiation of the coloration values, and logarithmic conversion of the raw and derivative values were compared in terms of the precision and accuracy of the quantitative determination of corrosiveness, glucose, nitrate, and pH using the products. The best regression models for the determination were provided by the combination of pseudocolor imaging and differentiation (nitrate and pH); pseudocolor imaging, differentiation, and square-conversion (corrosiveness); or all of the techniques (glucose). When compared to the use of the original 10 raw coloration variables of red-green-blue, cyan-magenta-yellow-key black, and L*a*b* color models only, the above combinations improved the normalized mean absolute error from 14.8% to 3.09% (corrosiveness), 6.33% to 3.15% (glucose), 7.46% to 4.56% (nitrate), and 3.22% to 0.94% (pH). These achievements were largely attributed to the combination of multiple variables that have non-linear and nonmonotonic relationships with the chemical characteristics.     

New lower bounds on the radius of spatial analyticity for the KdV equation

The radius of spatial analyticity for solutions of the KdV equation is studied. It is shown that the analyticity radius does not decay faster than $t^{?1/4}$ as time t goes to infinity. This improves the works of Selberg and da Silva (2017) [30] and Tesfahun (2017) [34]. Our strategy mainly relies on a higher order almost conservation law in Gevrey spaces, which is inspired by the I-method.     

Recent Progress on Manganese-Based Nanostructures as Responsive MRI Contrast Agents

Manganese-based nanostructured contrast agents (CAs) entered the field of medical diagnosis through magnetic resonance imaging (MRI) some years ago. Although some of these Mn-based CAs behave as classic T₁ contrast enhancers in the same way as clinical Gd-based molecules do, a new type of Mn nanomaterials have been developed to improve MRI sensitivity and potentially gather new functional information from tissues by using traditional T₁ contrast enhanced MRI. These nanomaterials have been designed to respond to biological environments, mainly to pH and redox potential variations. In many cases, the differences in signal generation in these responsive Mn-based nanostructures come from intrinsic changes in the magnetic properties of Mn cations depending on their oxidation state. In other cases, no changes in the nature of Mn take place, but rather the nanomaterial as a whole responds to the change in the environment through different mechanisms, including changes in integrity and hydration state. This review focusses on the chemistry and MR performance of these responsive Mn-based nanomaterials.     

Synthesis and Characterization of Hydrophilic Trityl Radical TFO for Biomedical and Biophysical Applications

Tetrathiatriarylmethyl (TAM, trityl) radicals have found wide applications as spin probes/labels for EPR spectroscopy and imaging, and as polarizing agents for dynamic nuclear polarization. The high hydrophilicity of TAM radicals is essential for their biomedical applications. However, the synthesis of hydrophilic TAM radicals (e.g., OX063) is extremely challenging and has only been reported in the patent literature, to date. Herein, an efficient synthesis of a highly water-soluble TAM radical bis(8-carboxyl-2,2,6,6-tetramethylbenzo[1,2-d:4,5-d′]bis([1,3]dithiol-4-yl)-mono-(8-carboxyl-2,2,6,6-tetrakis(2-hydroxyethyl)benzo[1,2-d:4,5-d′]bis([1,3]dithiol-4-yl)methyl (TFO), which contains four additional hydroxylethyl groups, relative to the Finland trityl radical CT-03, is reported. Similar to OX063, TFO exhibits excellent properties, including high water solubility in phosphate buffer, low log P, low pK_a, long relaxation times, and negligible binding with bovine serum albumin. On the other hand, TFO has a sharper EPR line and higher O₂ sensitivity than those of OX063. Therefore, in combination with its facile synthesis, TFO should find wide applications in magnetic resonance related fields and this synthetic approach would shed new light on the synthesis of other hydrophilic TAM radicals.     

Synthesis of Highly Functionalized N,N-Diarylamides by an Anodic C,N-Coupling Reaction

We report an innovative, sustainable and straightforward protocol for the synthesis of N,N-diarylamides equipped with nonprotected hydroxyl groups by using electrosynthesis. The concept allows the application of various substrates furnishing diarylamides with yields up to 57 % within a single and direct electrolytic protocol. The method is thereby easy to conduct in an undivided cell with constant current conditions offering a versatile and short-cut alternative to conventional pathways.     

Kinetics and mechanism of trichloroisocyanuric acid/NaNO2-triggered nitration of aromatic compounds under acid-free and Vilsmeier-Haack conditions

Kinetics and mechanism of nitration of aromatic compounds using trichloroisocyanuric acid (TCCA)/NaNO₂, TCCA-N,N-dimethyl formamide (TCCA-DMF)/NaNO₂, and TCCA-N,N-dimethyl acetamide (TCCA-DMA)/NaNO₂ under acid-free and Vilsmeier-Haack conditions. Reactions followed second-order kinetics with a first-order dependence on [Phenol] and [Nitrating agent] ([TCCA], [(TCCA-DMF)], or [(TCCA-DMA)] >> [NaNO₂]). Reaction rates accelerated with the introduction of electron-donating groups and retarded with electron-withdrawing groups, but did not fit well into the Hammett's theory of linear free energy relationship or its modified forms like Brown-Okamoto or Yukawa-Tsuno equations. Rate data were analyzed by Charton's multiple linear regression analysis. Isokinetic temperature (β) values, obtained from Exner's theory for different protocols, are 403.7 K (TCCA-NaNO₂), 365.8 K (TCCA-DMF)/NaNO₂, and 358 K (TCCA-DMA)/NaNO₂. These values are far above the experimental temperature range (303-323 K), indicating that the enthalpy factors are probably more important in controlling the reaction.     

Distorted Phthalocyanines by Click Chemistry: Photoacoustic,Photothermal, and Surface-Enhanced Resonance Raman Studies

Distortion of nominally planar phthalocyanine macrocycles affects the excited state dynamics in that most of the excited-state energy decays through internal conversion. A click-type annulation reaction on a perfluorophthalocyanine platform appending a seven-membered ring to the β-positions on one or more of the isoindoles distorts the macrocycle and modulates solubility. The distorted derivative enables photoacoustic imaging, photothermal effects, and strong surface-enhanced resonance Raman signals.