Synthesis and characterization of an inert perchlorotriphenylmethyl triester radical, PTM-TE, are reported. PTM-TE was prepared by a facile 3-step synthesis using Friedal-Crafts reaction of tetrachlorobenzene with chloroform followed by ethoxycarbonylation and subsequent oxidation. PTM-TE is paramagnetic, and detected as a single sharp peak by EPR spectroscopy. In solution, the EPR linewidth of PTM-TE is highly sensitive to the dissolved oxygen content, thus enabling accurate measurement of oxygen concentration (oximetry). In addition, the radical also shows high reactivity to superoxide. The ester radical has the potential for use as a high-sensitive probe for determination of oxygen concentration and superoxide in biological systems. KeywordsPerchlorotriphenylmethyl radical; perchlorotriphenylmethyl triester; superoxide; free radicals; EPR; oximetry; spectrophotometry In 1900, Moses Gomberg reported the existence of a stable, trivalent organic free radical which challenged the prevailing belief that carbon could only have four chemical bonds. 1 As this report provided new possibilities to carbon chemistry, research aimed at understanding and developing these radicals continued to thrive and permeated through various fields of science including medicine and industrial applications. Most notably, Gomberg's work paved the way for future research on using persistent trityl radicals in clinical applications. [2][3][4] However, it is known that some radicals and diradicals are short-lived and very reactive -the half-life of triphenylmethyl radicals in aerated solution may be as low as a fraction of a second. Studies have also shown that these reactive radicals become stable and chemically inert upon perchlorination. [5][6][7][8] In light of this endeavor, highly chlorinated mono-, di-, and triarylmethanes were developed and since then they have become the most valuable chemical precursors of inert free radicals with estimated half-lives in the order of Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. NIH Public Access NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript 100 years. 6 Together, these studies have been regarded as both promising and significant. 5 As a result, the synthesis of perchlorinated trityl radical has become an immense undertaking with promising implications.The role of reactive oxygen species (ROS) such as superoxide, hydroxyl, and alkylperoxyl radicals has been linked to a variety of pathophysiological processes. 9 Since, oxidative stress leads to an increased production of ROS, especially superoxide, accurate determinatio...

A liquid with microbubbles is used as an effective ultrasound contrast agent in medical diagnosis to improve the contrast of ultrasonic image. The existence of bubbles in liquid may enhance it nonlinearity parameter. This paper is devoted to experimental demonstration of influence of microbubbles on the nonlinearity parameter B/A values. The contrast agent named Echovist 300 and a kind of aqua sonicated with different bubble contents were studied. Results indicate that the values of nonlinearity parameter depend on the presence of microbubbles obviously.

The modulation power consumption and the modulation efficiency are the key parameters of the electro-optic modulator, which directly affect the electro-optic modulator's photoelectric properties. Improving the performance of the electro-optic modulator, a micro-nano electro-optic modulator structure based on the Si/SiGe/Si material is proposed in this paper, which has low power consumption and high efficiency. After the plasma dispersion effects and the thermo-optic effects are analyzed, we can know that the performance of the electro-optic modulator could be affected by the carrier concentration and the temperature of modulator. Silicon Germanium (SiGe) material is attached to the common Silicon (Si) electro-optic modulator, and a large injection ratio is obtained from the Si/SiGe/Si double hetero-junction. With the modulation region's carrier concentration rise, and the working voltage and the power consumption of modulator all are reduced. The jugged active region structure is attached to the common Si electro-optic modulator, and the probability of inelastic collision among carriers is decreased, so the temperature rise of modulator can be reduced. The thermal-optic effects are weakened, and the modulation efficiency is increased. The simulation results show that the working voltage of the jugged SiGe modulator is less than that of the Silicon modulator at the same refractive index differences, and the jugged SiGe modulator has lower modulation power consumption; the jugged SiGe modulator's effective refractive index differences are more than the Silicon modulator's effective refractive index differences at the same working voltage, and the jugged SiGe modulator has higher modulation efficiency. Therefore, this jugged SiGe modulator is a micro-nano electro-optic modulator with lower power consumption and higher efficiency.