The role of physical literacy and mindfulness on health-related quality of life among college students during the COVID-19 pandemic.

This study aimed to examine the role played by the physical literacy and mindfulness in the health-related quality of life (QoL) of college students. In early 2022, 24,236 college students from three universities in southern China were recruited in the study. R software and the lavvan package was utilized to build the structural equation model. The measurement model was composed of three latent factors (physical literacy, mindfulness, and quality of life) and 16 observed variables in total. The results of the measurement model indicated goodness fit with p > .05 in Chi-square result, and GFI = .92. In addition, the comparative fit index (.92), Tucker-Lewis index (.91), root-mean-square error of approximation (.07), and root of mean square residual (.11) were in accord with the cutoff model-fit criteria. The results confirm that physical literacy and mindfulness can play a significant and positive role in the structural equation model of quality of life. In addition, this study provides initial evidence that mindfulness and physical literacy could potentially buffer declines in student QoL during the COVID-19 pandemic. Moreover, this study is the first to develop a structural equation model of QoL with multiple indicators, making it a strong addition to existing research on QoL during a pandemic.

Transcriptome and DNA Methylation Responses in the Liver of Yellowfin Seabream Under Starvation Stress.

Fish suffer from starvation due to environmental risks such as extreme weather in the wild and due to insufficient feedings in farms. Nutrient problems from short-term or long-term starvation conditions can result in stress-related health problems for fish. Yellowfin seabream (Acanthopagrus latus) is an important marine economic fish in China. Understanding the molecular responses to starvation stress is vital for propagation and culturing yellowfin seabream. In this study, the transcriptome and genome-wide DNA methylation levels in the livers of yellowfin seabream under 14-days starvation stress were analyzed. One hundred sixty differentially expressed genes (DEGs) by RNA-Seq analysis and 737 differentially methylated-related genes by whole genome bisulfite sequencing analysis were identified. GO and KEGG pathway enrichment analysis found that energy metabolism-related pathways such as glucose metabolism and lipid metabolism were in response to starvation. Using bisulfite sequencing PCR, we confirmed the presence of CpG methylation differences within the regulatory region of a DEG ppargc1a in response to 14-days starvation stress. This study revealed the molecular responses of livers in response to starvation stress at the transcriptomic and whole genome DNA methylation levels in yellowfin seabream.

Research on anthracnose grade of Camellia oleifera based on the combined LIBS and THz technology.

BACKGROUND: Anthracnose of Camellia oleifera is a very destructive disease that commonly occurs in the Camellia oleifera industry, which severely restricts the development of the Camellia oleifera industry. In the early stage of the Camellia oleifera suffering from anthracnose, only the diseased parts of the tree need to be repaired in time. With the aggravation of the disease, the diseased branches need to be eradicated, and severely diseased plants should be cut down in time. At present, aiming at the problems of complex experiments and low accuracy in detecting the degree of anthracnose of Camellia oleifera, a method is proposed to detect the degree of anthracnose of Camellia oleifera leaves by using terahertz spectroscopy (THz) combined with laser-induced breakdown spectroscopy (LIBS), so as to realize the rapid, efficient, non-destructive and high-precision determination of the degree of anthracnose of Camellia oleifera. RESULTS: Mn, Ca, Ca II, Fe and other elements in the LIBS spectrum of healthy and infected Camellia oleifera leaves with different degrees of anthracnose are significantly different, and the Terahertz absorption spectra of healthy Camellia oleifera leaves, and Camellia oleifera leaves with different degrees of anthracnose there are also significant differences. Partial least squares discriminant analysis (PLS-DA), support vector machine (SVM), and linear discriminant analysis (LDA) are used to establish the fusion spectrum anthracnose classification model of Camellia oleifera. Among them, the Root mean square error of prediction (RMSEP) and the prediction determination coefficient R2p of THz-LIBS-CARS-PLS-DA of prediction set are 0.110 and 0.995 respectively, and the misjudgment rate is 1.03%; The accuracy of the modeling set of THz (CARS)-LIBS (CARS)-SVM is 100%, and the accuracy of prediction set is 100%, after preprocessing of the multivariate scattering correction (MSC), the accuracy of the THz-LIBS-MSC-CARS modeling set is 100%, and the accuracy of prediction set is 100%; The accuracy rate of THz-LIBS-MSC-CARS-LDA of modeling set is 98.98%, and the accuracy rate of the prediction set is 96.87%. CONCLUSION: The experimental results show that: the SVM model has higher qualitative analysis accuracy and is more stable than the PLS-DA and LDA models. The results showed that: the THz spectrum combined with the LIBS spectrum could be used to separate healthy Camellia oleifera leaves from various grades of anthracnose Camellia oleifera leaves non-destructively, quickly and accurately.

Physarum polycephalum macroplasmodium exhibits countermeasures against TiO2 nanoparticle toxicity: A physiological, biochemical, transcriptional, and metabolic perspective.

Concerns about the environmental and human health implications of TiO2 nanoparticles (nTiO2) are growing with their increased use in consumer and industrial products. Investigations of the underlying molecular mechanisms of nTiO2 tolerance in organisms will assist in countering nTiO2 toxicity. In this study, the countermeasures exhibited by the slime mold Physarum polycephalum macroplasmodium against nTiO2 toxicity were investigated from a physiological, transcriptional, and metabolic perspective. The results suggested that the countermeasures against nTiO2 exposure include gene-associated metabolic rearrangements in cellular pathways involved in amino acid, carbohydrate, and nucleic acid metabolism. Gene-associated nonmetabolic rearrangements involve processes such as DNA repair, DNA replication, and the cell cycle, and occur mainly when macroplasmodia are exposed to inhibitory doses of nTiO2. Interestingly, the growth of macroplasmodia and mammal cells was significantly restored by supplementation with a combination of responsive metabolites identified by metabolome analysis. Taken together, we report a novel model organism for the study of nTiO2 tolerance and provide insights into countermeasures taken by macroplasmodia in response to nTiO2 toxicity. Furthermore, we also present an approach to mitigate the effects of nTiO2 toxicity in cells by metabolic intervention.

ST1926 inhibits glioma progression through regulating mitochondrial complex II.

The antitumor activity of atypical adamantyl retinoid ST1926 has been frequently reported in cancer studies; nevertheless, its effect on glioma has not been fully understood. Mitochondria are critical in regulating tumorigenesis and are defined as a promising target for anti-tumor therapy. In the present study, we found that ST1926 might be a mitochondria-targeting anti-glioma drug. ST1926 showed significantly inhibitory role in the viability of glioma cells mainly through inducing apoptosis and autophagy. The results showed that ST1926 alleviated mitochondria-regulated bioenergetics in glioma cells via reducing ATP production and promoting reactive oxygen species production. Importantly, ST1926 significantly impaired complex II (CII) function, which was associated with the inhibition of succinate dehydrogenase (SDH) activity. In addition, the effects of ST1926 on the induction of apoptosis and ROS were further promoted by the treatment of CII inhibitors, including TTFA and 3-NPA. Furthermore, the in vivo experiments confirmed the role of ST1926 in suppressing xenograft tumor growth with few toxicity. Therefore, ST1926 might be an effective anti-glioma drug through targeting CII.

Shikonin and 4-hydroxytamoxifen synergistically inhibit the proliferation of breast cancer cells through activating apoptosis signaling pathway in vitro and in vivo.

BACKGROUND: Tamoxifen (TAM) is a cell type-specific anti-estrogen and is applied to improve the survival of patients with estrogen receptor positive (ER +) breast cancer. However, long-term TAM use can induce serious drug resistance, leading to breast cancer recurrence and death in patients. Further, it is almost useless among patients with estrogen receptor negative (ER -) breast cancer. Shikonin (SK) is a natural product broadly explored in cancer therapy. Some studies have demonstrated the combined treatment of SK and clinical anticancer drugs including TAM on various tumors. However, the combined effect of SK and 4-hydroxytamoxifen (4-OHT) on ER- breast cancer is not known. The current study aimed to assess the combination effects of SK and 4-OHT on human breast cancer cells, MCF-7 (ER +) and MDA-MB-435S (ER -), in vitro and in vivo and to investigate the underlying mechanisms. METHODS: CCK-8 assays and flow cytometry were conducted to determine the cell viability and apoptotic profiles of human breast cancer cell lines (MCF-7 and MDA-MB-435S) treated with SK, 4-OHT, and the combination. ROS and JC-1 assays were used to determine ROS level and mitochondrial membrane potential. Western blot analysis was performed to investigate proteins that are associated with apoptosis. Haematoxylin & Eosin (HE) staining was used to detect the tumor and kidney morphology of mice. TUNEL and immunohistochemical staining were performed to detect Ki67 expression level and cell apoptotic profile in tumor tissues. RESULTS: SK and 4-OHT synergistically inhibited MCF-7 and MDA-MB-435S cell proliferation and promoted apoptosis by reducing mitochondrial membrane potential and increasing the intracellular ROS level. The combination of SK and 4-OHT activated the mitochondrial-dependent apoptosis and the death receptor pathways, significantly regulating the PI3K/AKT/Caspase 9 signaling pathway. Compared with SK and 4-OHT alone, the combination of SK and 4-OHT could better inhibit tumor growth in mice. CONCLUSION: The combination of SK and 4-OHT shows highly efficient anticancer effects on breast cancer therapy. SK may be a promising candidate as an adjuvant to 4-OHT for breast cancer treatments, especially for ER- breast cancer.

T2 Fluid-Attenuated Inversion Recovery Resection for Glioblastoma Involving Eloquent Brain Areas Facilitated Through Awake Craniotomy and Clinical Outcome.

BACKGROUND: Despite evidence that a greater extent of resection (EOR) improves survival, the role of extended resection based on magnetic resonance imaging (MRI) fluid-attenuated inversion recovery (FLAIR) in the prognosis of glioblastoma (GBM) remains controversial. This study aims to investigate the role of additional resection of FLAIR-detected abnormalities and its influence on clinical outcomes of patients with GBM. METHODS: Forty-six patients with newly diagnosed GBM involving eloquent brain areas were included. Surgeries were performed using awake craniotomy (AC) or AC combined with sodium fluorescein (SF) guidance. Following total removal of the contrast-enhancing tumor area, the EOR of FLAIR abnormalities was dichotomized to identify the best separation threshold for progression-free survival (PFS), overall survival (OS), and 30-day postoperative neurologic function of patients with GBM. RESULTS: The threshold for removal of FLAIR abnormalities affecting survival was determined to be 25%. The median OS and PFS were shorter in the group with FLAIR resection <25% compared with the group with FLAIR resection ≥25% (12 months vs. 26 months; P = 0.001 and 6 months vs. 15 months; P = 0.016, respectively). Univariate and multivariate analyses identified tumor location within or near the eloquent brain areas and the 25% threshold for FLAIR EOR as independent factors affecting OS and PFS. CONCLUSIONS: Identifying a feasible threshold for the resection of FLAIR abnormalities is valuable in improving the survival of patients with GBM. Extended resection of GBM involving eloquent brain areas was safe when using a combination of AC and SF-guided surgery.

Novel Podophyllotoxin Derivatives as Potential Tubulin Inhibitors: Design, Synthesis, and Antiproliferative Activity Evaluation.

A number of podophyllotoxin derivatives (3A-3J) had been designed and synthesized, and their biological activities were evaluated in this study. Moreover, the antiproliferation activities of these compounds against four human cancer cell lines (HepG2, HeLa, A549, and MCF-7) were also tested. The results indicated that the most promising compound 3D displayed potent inhibitory activity over the four human cancer cell lines and was further demonstrated to have potent tubulin polymerization inhibitory effects without damaging the non-cancer cells. Additionally, 3D was verified to effectively interfere with tubulin and could prevent the mitosis of cancer cells, leading to cell cycle arrest and eventually inducing apoptosis in a dose- and time-dependent manner. Moreover, the Western blotting and siRNA results showed that Bcl-2 was downregulated in HepG2 cells treated with 3D. Finally, the molecular docking simulation results revealed that 3D could fit well in the colchicine-binding pocket. Taken together, this study has provided certain novel antitubulin agents for possible cancer chemotherapy.

Nano-sized TiO2 (nTiO2) induces metabolic perturbations in Physarum polycephalum macroplasmodium to counter oxidative stress under dark conditions.

Nano-sized TiO2 (nTiO2) exerts an oxidative effect on cells upon exposure to solar or UV irradiation and ecotoxicity of the nTiO2 is an urgent concern. Little information is available regarding the effect of TiO2 on cells under dark conditions. Metabolomics is a unique approach to the discovery of biomarkers of nTiO2 cytotoxicity, and leads to the identification of perturbed metabolic pathways and the mechanism underlying nTiO2 toxicity. In the present study, gas chromatography mass spectrometry (GC/MS)-based metabolomics was performed to investigate the effect of nTiO2 on sensitive cells (P. polycephalum macroplasmodium) under dark conditions. According to the multivariate pattern recognition analysis, at least 60 potential metabolic biomarkers related to sugar metabolism, amino acid metabolism, nucleotide metabolism, polyamine biosynthesis, and secondary metabolites pathways were significantly perturbed by nTiO2. Notably, many metabolic biomarkers and pathways were related to anti-oxidant mechanisms in the living organism, suggesting that nTiO2 may induce oxidative stress, even under dark conditions. This speculation was further validated by the biochemical levels of reactive oxygen species (ROS), 8-hydroxy-2-deoxyguanosine (8-OHdG), and total soluble phenols (TSP). We inferred that the oxidative stress might be related to nTiO2-induced imbalance of cellular ROS. To the best of our knowledge, the present study is the first to investigate the nTiO2-induced metabolic perturbations in slime mold, provide a new perspective of the mechanism underlying nTiO2 toxicity under dark conditions, and show that metabolomics can be employed as a rapid, reliable and powerful tool to investigate the interaction among organisms, the environment, and nanomaterials.

Role of esophagogastroduodenoscopy in detecting distal duodenal lesions: A single-center pilot study in Southern China.

OBJECTIVE: Esophagogastroduodenoscopy (EGD) is a standard instrument for detecting upper gastrointestinal lesions. However, the distal duodenum is often missed. This study aimed to clarify the diagnostic role of EGD in the distal duodenum. METHODS: This retrospective study enrolled patients with distal duodenal lesions who underwent EGD between January 2004 and July 2016 at our center. The rate of missed diagnosis using EGD examination was calculated. Logistic regression analysis was performed to identify the factors associated with the missed diagnoses. RESULTS: Sixty-three patients were included in the study. The overall diagnostic rate of distal duodenal lesions on EGD was 58.7%. After excluding the patients in whom the EGD did not reach the distal duodenum, this rate rose to 82.2%. In univariate analysis, intravenous sedation (26.8% vs 68.2%, odds ratio [OR] 0.171, P = 0.002), signs of lesions adjacent to the stomach (19.4% vs 62.5%, OR 0.099, P = 0.001), prior enteroscopy experience (15.0% vs 87.0%, OR 0.026, P < 0.001), and endoscopists with experiences of over 10 years (13.8% vs 64.7%, OR 0.087, P = 0.000) were associated with a decreased risk of missed diagnosis. In multivariate analysis, signs of lesions adjacent to the stomach (OR 0.167, P = 0.039) and prior enteroscopy experience (OR 0.035, P < 0.001) were significant independent protective factors. CONCLUSION: EGD may be important in diagnosing distal duodenal lesions. Patients with gastric retention, blood in the stomach or erosion in the proximal duodenum may benefit from the deep insertion of EGD.

Modified submucosal tunneling endoscopic resection for submucosal tumors in the esophagus and gastric fundus near the cardia.

Background and study aims Submucosal tunneling endoscopic resection with double opening (DO-STER) was developed by our group for the resection of submucosal tumors in the esophagus and gastric fundus near the cardia. This study aimed to provide a preliminary evaluation of feasibility and safety of DO-STER. Methods The key to DO-STER is the creation of a tunnel opening in the mucosa over the inferior border of the tumor. During resection, the tumor can be gradually pushed out of the submucosal tunnel through the opening, leaving enough space for operation within the tunnel. A total of 10 tumors resected by DO-STER were retrospectively reviewed. Results All tumors were successfully resected by DO-STER. One tumor was located at the lower esophagus, four at the esophagogastric junction, and five at the gastric fundus near the cardia. Tumor size ranged from 1.0 × 1.2 cm to 3.5 × 5.0 cm, and all tumors originated from the muscularis propria. Operative times ranged from 45 to 150 minutes. No delayed bleeding or perforation occurred. Conclusion DO-STER seems to provide an alternative approach for resection of tumors in the esophagus and gastric fundus near the cardia.

Low Discrepancy Between Tissue Biopsy Plus Magnifying Endoscopy With Narrow-Band Imaging and Endoscopic Resection in the Diagnosis of Gastric Epithelial Neoplasia (STROBE).

Tissue biopsy is often not very accurate for the diagnosis of gastric epithelial neoplasia (GEN), and the results differ notably from endoscopic resection (ER) in terms of the pathological diagnosis. The aims of this study were to evaluate the diagnostic performances of biopsy, magnifying endoscopy with narrow-band imaging (ME-NBI), and biopsy plus ME-NBI for GEN.This study retrospectively analyzed 101 cases diagnosed as GEN using ER samples. The discrepancies between biopsy and ER, as well as between biopsy plus ME-NBI and ER in the diagnosis of GEN were evaluated. Factors that contributed to such discrepancies were analyzed. The sensitivity and specificity of biopsy and ME-NBI for the diagnosis of high-grade neoplasia (HGN) were determined.The discrepancy in the pathological diagnosis between biopsy and ER was 39.6% for GEN and 54.2% for HGN. The discrepancy between biopsy combined with ME-NBI and ER was 15.9% for GEN and 10.2% for HGN. Factors that undermined the diagnostic accuracy of biopsy included the lesion size (≤10 mm, odds ratio [OR] 1; 10-20 mm, OR 0.2, 95% confidence interval [CI] 0.1-0.7; >20 mm, OR 0.5, 95% CI 0.1-2.1, P = 0.03) and the number of biopsy fragments (OR 0.6, 95% CI 0.5-0.8, P = 0.001). The sensitivity and specificity for HGN were 45.8% (33.7%-58.3%) and 100% (87.5%-100%) for biopsy, and 88.1% (77.5%-94.1%) and 92.9% (81.0%-97.5%) for ME-NBI, respectively.In conclusion, biopsy-based diagnoses for GEN should be interpreted with caution. Biopsy combined with ME-NBI can contribute to the diagnosis of GEN, which improves diagnostic consistency with pathological result of ER specimens.

Single-balloon enteroscopy for small bowel diseases: results from an initial experience at a single Chinese center.

OBJECTIVE: This study aimed to evaluate the performance, diagnostic yield, and safety of single-balloon enteroscopy (SBE) at a Chinese tertiary-care center. METHODS: A total of 67 patients with suspected small bowel diseases who underwent SBE via the oral and/or anal routes from January 2009 to August 2011 were retrospectively analyzed. Data were extracted from electronic clinical and endoscopy records. The indications, SBE procedure time, diagnostic yield and complications were summarized and evaluated. RESULTS: A total of 42 SBE procedures through the oral route and 38 via the anal route were performed in these 67 patients. Patients were referred mainly for obscure gastrointestinal bleeding (OGIB) (40.3%) and abdominal pain (29.8%). The mean procedure duration was 68.1 min from the oral cavity and 77.5 min from the anus. The estimated depth of insertion was 247.6 ± 80.3 cm from the oral cavity and 131.1 ± 68.7 cm from the anus. The overall significant diagnostic yield was 68.7%. In patients with OGIB and unexplained chronic abdominal pain, the diagnostic yield was 74.1% and 50.0%, respectively. There were no significant complications. CONCLUSION: SBE appears to be a safe and effective method for the diagnosis and treatment of deep small bowel disease.

Calf thymus DNA-stabilized polythiophene fluorescence probe for label-free detection of spermine.

It is a challenge to detect molecules lacking a chromophore, such as polyamines, by optical methods since they are insensitive to light. In order to detect the optical signals, it is compulsory to derive these molecules with optical labels, which, however, is complicated, time-consuming and may be expensive. In this work, a highly specific strategy for spermine detection is developed on the basis of the iodide-induced conformational change of polythiophene. By using the triplex complex of negatively charged double-stranded calf thymus DNA (ctDNA)-stabilized cationic polythiophene as a fluorescent probe, the highly specific detection of spermine could be realized since polythiophene, which will be released from the triplex complex owing to the condensation and aggregation of ctDNA with spermine, undergoes a conformational change from the random-coiled non-planar state to the highly conjugated planar form in the presence of iodide, resulting in a yellow-to-red color conversion and fluorescence quenching. The quenched fluorescence was found to be proportional to the spermine concentrations in the range of 1.2-50 µM with the limit of detection (LOD) being 0.5 µM (3σ/k).

Naftopidil and tolterodine in the medical expulsive therapy for intramural ureteral stones: a prospective randomized study.

We performed a randomized, prospective study to assess the possible role of combined naftopidil and tolterodine for facilitating the spontaneous expulsion of intramural ureteral stones. A total of 76 patients with intramural ureter stones were included in the study from December 2007 to February 2011. Patients were randomized to one of three treatment groups. Group A patients received naftopidil 25 mg/day, group B patients received naftopidil 25 mg/day plus tolterodine 2 mg (twice a day), and group C patients received tolterodine 2 mg (twice a day). Both groups were followed up for 2 weeks. The stone expulsion rate and time and the number of pain episodes were obtained. Subjects rated the urgency associated with each micturition using the Urinary Sensation Scale (USS). Pain descriptions were recorded by the patients using the visual analog scale (VAS). A significant difference was shown for the expulsion rate between the group C and the other two groups (P < 0.001 by log rank test). In groups A, B and C, the mean number of pain episodes was 2.25 ± 0.90, 1.38 ± 1.37 and 1.54 ± 1.18, respectively. The USS score for groups A, B and C at 3 days was 2.32 ± 0.55, 1.4 ± 0.58 and 1.34 ± 0.49, respectively. It was 1.75 ± 0.44, 1.2 ± 0.41 and 1.22 ± 0.42, respectively, at 7 days. On the other hand, a statistically significant difference was found between groups A and B, and groups A and C in relation to the visual analog scale score on days 3 and 7, respectively. Treatment with naftopidil and tolterodine appears to be beneficial in intramural ureteral stones clearance, particularly in the intramural ureter with symptoms of vesical irritability.

Differential Proteome Analysis of Breast and Thigh Muscles between Korean Native Chickens and Commercial Broilers.

The Korean native chickens (Woorimotdak™, KNC) and commercial broilers (Ross, CB) show obvious differences in meat flavor after cooking. To understand the contribution of protein and peptide for meat flavor, 2-dimensional (2-D) gel electrophoresis and matrix-assisted laser desorption-ionization time-of-flight (MALDI-TOF) mass spectrometry was performed. A total of 16 protein spots were differentially expressed in the breast and thigh meat between the two breeds. A total of seven protein spots were represented by different levels between KNC and CB for breast meat. Among them three protein spots (TU39149, TU40162 and TU39598) showed increases in their expressions in KNC while other four protein spots (BU40125, BU40119, BU40029 and BU39904) showed increases in CB. All nine protein spots that were represented by different levels between KNC and CB for thigh meat showed increases in their expression in KNC. Phosphoglucomutase 1 (PGM 1), myosin heavy chain (MyHC), heat shock protein B1 (HSP27), cytochrome c reductase (Enzyme Q), Glyoxylase 1, DNA methyltransferase 3B (DNA MTase 3) were identified as the main protein spots by MALDI-TOF mass spectrometry. These results can provide valuable basic information for understanding the molecular mechanism responsible for breed specific differences in meat quality, especially the meat flavour.

Identification of an antifungal metabolite produced by a potential biocontrol Actinomyces strain A01.

Actinomyces strain A01 was isolated from soil of a vegetable field in the suburb of Beijing, China. According to the morphological, cultural, physiological and biochemical characteristics, and 16S rDNA sequence analysis, strain A01 was identified as Streptomyces lydicus. In the antimicrobial spectrum test strain A01 presented a stable and strong inhibitory activity against several plant pathogenic fungi such as Fusarium oxysporum, Botrytis cinerea, Monilinia laxa, etc. However, no antibacterial activity was found. In pot experiments in greenhouse, the development of tomato gray mold was markedly suppressed by treatment with the fermentation broth of the strain A01, and the control efficacy was higher than those of Pyrimethanil and Polyoxin. A main antifungal compound (purity 99.503%) was obtained from the fermentation broth of strain A01 using column chromatography and HPLC. The chemical structural analysis with U V, IR, MS, and NMR confirmed that the compound produced by the strain A01 is natamycin, a polyene antibiotic produced by S. chattanovgensis, S. natalensis, and S. gilvosporeus, widely used as a natural biological preservative for food according to previous reports. The present study revealed a new producing strain of natamycin and its potential application as a biological control agent for fungal plant diseases.

Enhanced plasmon resonance light scattering signals of colloidal gold resulted from its interactions with organic small molecules using captopril as an example.

Gold nanoparticles are known for their plasmon resonance absorption (PRA) depending on their size. Our this investigation shows that plasma resonance light scattering (PRLS) signals in the corresponding PRA region could be measured using a common spectrofluorometer, and be enhanced when aggregation of gold nanoparticles occurs due to their interaction with organic small molecules (OSMs). Using captopril (Cap) as an example, we investigated the interactions of gold nanoparticles with OSMs in order to propose a general method of OSMs such as typical clinic organic drugs. In aqueous medium of pH 2.09, there are about 2.2 x 10(3) Cap molecules covalently binding to the surface of a 10-nm diameter gold nanoparticle through the thiol functional group of Cap, and thus forms a core-shell assembly of [(Au)(31000)]@[(Cap)(2200)], displaying strong enhanced PRLS signals in the PRA region of gold colloid. The PRLS intensities characterized at 553.0 nm were found to be proportional to the concentration of Cap over the range of 0.1-1.7 mg L(-1) with the determination limit (3sigma) of 32.0 microg L(-1). With that, Cap in pharmaceutical preparations could be determined with the recovery of 97.0-104.5% and R.S.D. of less than 2.4%.