[Relationship between CT findings and immunohistochemical types of gastrointestinal stromal tumors].

OBJECTIVE: To evaluate the relationship between CT findings and immunohistochemical types of gastrointestinal stromal tumors (GIST). METHODS: CT imaging and clinicopathological data of 85 patients with GIST were analyzed retrospectively. The CT findings of GIST including lesion location, size, contour, boundary, tumor growth pattern, degree of enhancement, necrosis and calcification, were summarized and compared with the immunohistochemical types of the GIST. RESULTS: Of the 85 patients, smooth muscle differentiation was in 26 cases (30.6%), neural differentiation in 20 (23.5%) , both smooth muscle and neural differentiation in 10 (11.8%) and no obvious differentiation in 29 (34.1%) cases. GISTs occurred in the duodenum were more frequently seen in muscle type than in any other types, GIST with smooth muscle differentiation had higher prevalence of huge mass (larger than 10 cm), distinctive enhancement and extensive necrosis than other types (P < 0.05). There was no significant difference in the relationships of immunohistochemical types with tumor contour, boundary, growth pattern and calcification among the four groups of GIST (P > 0.05). CONCLUSIONS: CT scan is the most important and effective method for diagnosis of GIST. Analyzing CT signs has some potential value in judgmet of immunohistochemical types of GIST.

A 200-fold quantum yield boost in the photoluminescence of silver-doped Ag(x)Au(25-x) nanoclusters: the 13th silver atom matters.

The rod-shaped Au25 nanocluster possesses a low photoluminescence quantum yield (QY=0.1%) and hence is not of practical use in bioimaging and related applications. Herein, we show that substituting silver atoms for gold in the 25-atom matrix can drastically enhance the photoluminescence. The obtained Ag(x)Au(25-x) (x=1-13) nanoclusters exhibit high quantum yield (QY=40.1%), which is in striking contrast with the normally weakly luminescent Ag(x)Au(25-x) species (x=1-12, QY=0.21%). X-ray crystallography further determines the substitution sites of Ag atoms in the Ag(x)Au(25-x) cluster through partial occupancy analysis, which provides further insight into the mechanism of photoluminescence enhancement.

A simple model for understanding the fluorescence behavior of Au25 nanoclusters.

In this work, we synthesized Au25 nanoclusters protected by 2-(naphthalen-2-yl)ethanethiolate. Our experiments revealed that the luminescence of this nanocluster consists of two bands, namely, band I centered at 740 nm and band II centered at 680 nm. Compared with 2-phenylethanethiolate protected Au25 nanoclusters, this new nanocluster has a much higher QY (quantum yield) value (6.5 times higher). Fluorescence lifetime measurements showed multiple components, i.e. 0.15 ns, ∼20 ns and ∼150 ns. With an increase in the electropositivity of the nanocluster, the fluorescence intensity of the nanocluster exhibits a significant enhancement. Since the 2-(naphthalen-2-yl)ethanethiolate protected Au25 nanocluster shares the same Au13/Au12 core-shell structure as the 2-phenylethanethiolate protected nanocluster, the band II fluorescence implies that the surface ligands play a major role in the origin of the fluorescence.

One-pot synthesis of phenylmethanethiolate-protected Au20(SR)16 and Au24(SR)20 nanoclusters and insight into the kinetic control.

We report two synthetic routes for concurrent formation of phenylmethanethiolate (-SCH2Ph)-protected Au20(SR)16 and Au24(SR)24 nanoclusters in one-pot by kinetic control. Unlike the previously reported methods for thiolate-protected gold nanoclusters, which typically involve rapid reduction of the gold precursor by excess NaBH4 and subsequent size focusing into atomically monodisperse clusters of a specific size, the present work reveals some insight into the kinetic control in gold-thiolate cluster synthesis. We demonstrate that the synthesis of -SCH2Ph-protected Au20 and Au24 nanoclusters can be obtained through two different, kinetically controlled methods. Specifically, route 1 employs slow addition of a relatively large amount of NaBH4 under slow stirring of the reaction mixture, while route 2 employs rapid addition of a small amount of NaBH4 under rapid stirring of the reaction mixture. At first glance, these two methods apparently possess quite different reaction kinetics, but interestingly they give rise to exactly the same product (i.e., the coproduction of Au20(SCH2Ph)16 and Au24(SCH2Ph)20 clusters). Our results explicitly demonstrate the complex interplay between the kinetic factors that include the addition speed and amount of NaBH4 solution as well as the stirring speed of the reaction mixture. Such insight is important for devising synthetic routes for different sized nanoclusters. We also compared the photoluminescence and electrochemical properties of PhCH2S-protected Au20 and Au24 nanoclusters with the PhC2H4S-protected counterparts. A surprising 2.5 times photoluminescence enhancement was observed for the PhCH2S-capped nanoclusters when compared to the PhC2H4S-capped analogues, thereby indicating a drastic effect of the ligand that is merely one carbon shorter.

Crucian carp (Carassius carassius) VTG monoclonal antibody: development and application.

The vitellogenin (VTG) in fish has been used as an important biomarker for monitoring endocrine disrupting compounds (EDCs). This paper reports the development of a new monoclonal antibody (McAb) against the VTG of crucian carp (Carassius carassius). The McAb has a molecular weight of 149.4 kDa (heavy chain: 53.1 kDa; light chain: 21.6 kDa), and double diffusion indicated that it belongs to the IgG1 subclass. The titer is 10(5)-10(6) and the affinity constant (K(aff)) is 7.0 x 10(8)L/mol, showing the high specificity and sensitivity of the antibody. The established sandwich ELISA was sensitive with a detection limit of VTG 0.98 ng/mL. The cross-reactivity of antibody was detected in cyprinids such as rare minnow, zebrafish, and carp. This ELISA was used to detect the variation of VTG in crucian carp exposed to secondary effluent and reclaimed water from the Gaobeidian sewage treatment plant (SRP). The VTG induction in secondary effluent was higher than that in reclaimed effluent and the VTG levels in juvenile crucian carp increased with increasing exposure time. The VTG concentration in male fish from downstream of the Gaobeidian STP was 88.62+/-827.73 microg/mL, while that from a control site was undetectable.