Two-Photon Excitation of Gold Nanorods Interrupted by Extremely Fast Solvent-to-Metal Electron Transfer

Gold nanorods (Au NRs) have been widely exploited for various biomedical applications due to their strong two-photon photoluminescence (2PPL). 2PPL of Au NRs were found significantly quenched in organic solvents, which was originally ascribed to reduced luminescence yields caused by electron transfer quenching. It was recently found that excitation of 2PPL of Au NRs involved two sequential one-photon absorption steps. Here various ultrafast spectroscopic techniques have been employed to demonstrate two different solvent-to-metal electron transfer pathways: electron transfer from organic solvents to sp and d band holes of excited Au NRs, which have different influences on 2PPL of Au NRs. Electron transfer to sp band holes occurs extremely fast (∼25 fs), which blocks absorption of the second photon and reduces overall two-photon excitation efficiency, which is the dominant mechanism for the observed 2PPL quenching. In contrast, electron transfer to d band holes hinders the radiative recombination process and results in reduced luminescence yield, which plays the minor contribution for the observed 2PPL quenching. This work has proposed and demonstrated an additional brand-new quenching mechanism of 2PPL emission of Au NRs: extremely fast electron transfer to the intermediate states within the laser pulse duration interrupts sequential absorption of two photons, which results in significantly reduced two-photon excitation efficiency. This study provides new insight on fundamental understanding of two-photon excitation processes and nonlinear optical properties of these materials

Mean plasma concentration-time curves of test and reference formulations of febuxostat after single-dosing of 1 tablet of 40-mg (A) and 80-mg (B).

<p>Mean plasma concentration-time curves of test and reference formulations of febuxostat after single-dosing of 1 tablet of 40-mg (A) and 80-mg (B).</p

CD133 Expression and the Prognosis of Colorectal Cancer: A Systematic Review and Meta-Analysis

<div><h3>Objective</h3><p>CD133 has recently been reported as a marker of cancer stem-like cells in colorectal cancer (CRC). However, its predictive value in CRC still remains controversial. In this study, we aimed to evaluate the association between the expression of CD133 and clinicopathological features and the outcome of CRC patients by performing a meta-analysis.</p> <h3>Methods</h3><p>A comprehensive literature search for relevant studies published up to December 2012 was performed using PubMed, MEDLINE and ISI Web of Science. Only articles in which CD133 antigen was detected in situ localisation by immunohistochemical staining were included. This meta-analysis was done using RevMan 4.2 software.</p> <h3>Results</h3><p>We found that a total of 15 studies involving 810 CD133-high and 1487 CD133-low patients met the inclusion criteria for the analysis of 5-year overall survival (OS) rate. In a random-effects model, the results showed that CD133-high expression in colorectal cancer was an independent prognostic marker correlating with both OS rate (RR = 0.67, 95%CI 0.54–0.82, P<0.01) and disease free survival (DFS) rate (RR = 0.71, 95%CI 0.52–0.96, P = 0.03). CD133-high expression was also associated with more T3,4 tumor invasion, N positive and vascular invasion cases, corresponding to a risk difference of 1.12 (95%CI 1.01–1.23, P = 0.03), 1.31 (95%CI 1.06–1.63, P = 0.01) and 1.24 (95%CI 1.08–1.41, P<0.01), respectively. However, when types of histology, lymphatic invasion and distant metastasis were considered, CD133 overexpression was not significantly related with these clinicopathological parameters.</p> <h3>Conclusion</h3><p>Our meta-analysis results suggest that CD133 is an efficient prognostic factor in CRC. Higher CD133 expression is significantly associated with poorer clinical outcome and some clinicopathological factors such as T category, N category and vascular invasion in CRC patients.</p> </div

The mass spectrometry (MS) parameters for assays of febuxostat.

<p>The mass spectrometry (MS) parameters for assays of febuxostat.</p

The complete chloroplast genome sequence and phylogenetic analysis of <i>Strobilanthes dalzielii</i> (W.W.Sm.) Benoist 1935 (Acanthaceae)

Strobilanthes dalzielii of Acanthaceae is an herb species with potentially extensive applications for its pharmaceutical and ornamental values. Due to taxonomic complications and limited genetic information, the structural characteristics, and phylogenetic relationships of the S. dalzielii chloroplast genome were assembled and characterized here for the first time. The complete chloroplast genome of S. dalzielii was 144,580 bp in length. The genome is quadripartite in structure and consists of a large single-copy region (92,137 bp) and a small single-copy region (17,669 bp), which are separated by a pair of inverted repeats (each 17,387 bp). A total of 125 genes were annotated, including 80 protein-coding, 37 transfer RNA, and eight ribosomal RNA genes. The overall GC content was 36.4%. Phylogenetic analysis based on the complete chloroplast genome sequence of 21 taxa within the tribe Ruellieae of Acanthaceae using the maximum likelihood and Bayesian inference methods revealed that Strobilanthes diverged after Ruellia; S. dalzielii is closely related to S. tonkinensis. The genomic data obtained from this study will serve as valuable information to the species delimitation and genetic classification of Strobilanthes.</p

Funnel plot of studies used in the analysis of CRC 5-year OS rat

<p>Funnel plot of studies used in the analysis of CRC 5-year OS rat</p

Aflatoxin B₁ and sterigmatocystin in wheat and wheat products from supermarkets in China

<p>Wheat is an important cereal but it is often contaminated with mycotoxins. The natural occurrence of aflatoxin B₁ (AFB₁) and sterigmatocystin (STC) was determined in 178 food samples (32 wheat samples and 146 wheat products) purchased from Chinese supermarkets. The methodology was validated, the wheat and wheat products samples were treated with a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) and quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). From these samples 18.8% of wheat and 8.2% of cracker samples were contaminated with AFB₁. Mean levels were 0.06 µg/kg and 0.05µg/kg, respectively. There was no AFB₁ contamination in white bread or whole meal bread. Meanwhile 53.1% of wheat, 59.2% of crackers, 20.8% of white bread and 16% of whole meal bread samples were contaminated with STC. The mean levels were 0.07, 0.79, 0.12 and 0.12 µg/kg respectively. Although the levels were low, this demonstrates the need for more comprehensive surveys for these two mycotoxins in wheat and wheat products from China.</p

LC-MS/MS of febuxostat of blank plasma solution(A), reference standards solution (B), blank plasma with reference standards solution(C) and subject plasma solution (D).

<p>LC-MS/MS of febuxostat of blank plasma solution(A), reference standards solution (B), blank plasma with reference standards solution(C) and subject plasma solution (D).</p

Pharmacokinetic parameters of febuxostat after single-dosing in healthy Chinese male volunteers.

<p>Pharmacokinetic parameters of febuxostat after single-dosing in healthy Chinese male volunteers.</p

CD133 expression and 5-year OS rate.

<p>CD133 expression and 5-year OS rate.</p