Electrochemical detection of uric acid in human serum based on ultrasmall Ta2O5 nanoparticle anchored Pt atom with ultrahigh uricase and catalase activities.

The synthesis of ultrasmall Ta2O5 nanoparticle anchored Pt atom using aspartic acid-functionalized graphene quantum dot (Asp-GQD) is reported. The Asp-GQD was combined with tantalic acid and chloroplatinic acid to rapidly form water-soluble Ta-Asp-GQD and Pt-Asp-GQD complex. Followed by thermal annealing at 900 °C in N2 to obtain Ta2O5-Asp-GQD-Pt. The study shows that the introduction of Asp-GQD as a chelating agent and p-type semiconductor achieves to the formation of ultrasmall Ta2O5 nanoparticle, PN junction at the interface and Pt single atom anchored on the surface of Ta2O5 nanocrystals. The unique structure realizes ultrahigh uricase activity and catalase activities of Ta2O5-Asp-GQD-Pt. The Ta2O5-Asp-GQD-Pt was used as the bifunctional sensing material for the construction of an electrochemical uric acid sensor. The differential pulse voltammetric current at 0.45 V linearly increases with the increase of uric acid concentration in the range 0.001-5.00 mM with the detection limit of 0.41 µM (S/N = 3). The sensor exhibits a much better sensitivity compared with the reported methods for the detection of uric acid. The proposed analytical method has been applied to the electrochemical detection of uric acid in human serum with a spiked recovery of 95-105%. The study also offers one way to design and synthesize multifunctional sensing materials with high catalytic activity.

Transcriptome Analysis of Inhibitory Effect of Astaxanthin Against HepG2 Cell Lines / 肿瘤防治研究

Objective To investigate the gene expression differences of hepatocellular carcinoma (HCC) cells treated with astaxanthin and to analyze its biological information. Methods After treated with astaxanthin, the total RNA of HCC cells was extracted with TRIzol reagent. Illumina TruseqTM RNA sample Prep Kit was used for RNA-seq library construction and sequencing. We analyzed the differentially-expressed genes and function enrichments. Results Transcriptomic analysis showed that there were 39 642 566 and 497 155 920 reads in the control group and treatment group, respectively; the proportion of clean reads obtained by filtration were 94.89% and 93.56%, respectively. A total of 77 344 transcripts were detected, with 4 997 genes with significant differences in expression, among which 1 564 genes were up-regulated and 3 433 genes were down-regulated. Conclusions Astaxanthin may participate in several biological processes and signaling pathways of tumors. Significant repression of translation process by astaxanthin may result in the growth inhibition of HCC.

Electrochemical detection of carbendazim with mulberry fruit-like gold nanocrystal/multiple graphene aerogel and DNA cycle amplification.

An aptasensor for electrochemical detection of carbendazim is reported with mulberry fruit-like gold nanocrystal (MF-Au)/multiple graphene aerogel (MGA) and DNA cycle amplification. HAuCl4 was reduced by ascorbic acid in a CTAC solution containing KBr and KI and formed trioctahedron gold nanocrystal. The gold nanocrystal underwent structural evolution under enantioselective direction of L-cysteine. The resulting MF-Au shows a mulberry fruit-like nanostructure composed of gold nanocrystals of about 200 nm as the core and many irregular gold nanoparticles of about 30 nm as the shell. The exposure of high-index facets improves the catalytic activity of MF-Au. MF-Au/MGA was used for the construction of an aptasensor for electrochemical detection of carbendazim. The aptamer hybridizes with assistant strand DNA to form duplex DNA. Carbendazim binds with the formed duplex DNA to release assistant strand DNA, triggering one three-cascade DNA cycle. The utilization of a DNA cycle allows one carbendazim molecule to bring many methylene blue-labeled DNA fragments to the electrode surface. This promotes significant signal amplification due to the redox reaction of methylene blue. The detection signal is further enhanced by the catalysis of MF-Au and MGA towards the redox of methylene blue. A differential pulse voltammetric signal, best measured at - 0.32 V vs. Ag/AgCl, increases linearly with the carbendazim concentration ranging from 1.0 × 10-16 to 1.0 × 10-11 M with a detection limit of 4.4 × 10-17 M. The method provides ultrahigh sensitivity and selectivity and was successfully applied to the electrochemical detection of carbendazim in cucumber. This study reports on an ultrasensitive aptasensor for electrochemical detection of carbendazim in cucumber based on mulberry fruit-like gold nanocrystal-multiple graphene aerogel and DNA cycle double amplification.

Colorimetric detection of chlorpyrifos in peach based on cobalt-graphene nanohybrid with excellent oxidase-like activity and reusability.

Cobalt nanocrystal has been widely used as nano-enzyme for sensing and catalysis due to its high stability and low cost, but poor catalytic activity limits its applications in bioanalysis. The study reports one strategy for synthesis of cobalt-graphene nanohybrid. Histidine-functionalized graphene quantum dot (His-GQD) was bound to graphene sheet via π-π stacking and then combined with cobalt ions in the presence of cetyltrimethylammonium chloride to form stable complex and finally reduced under nitrogen to obtain Co-His-GQD-G. The as-synthesized nanohybrid offers well-defined three-dimensional structure and quasi-superparamagnetism. The cobalt nanoparticles were well dispersed on graphene sheets. The unique structure improves oxidase-like activity of Co-His-GQD-G. Further, Co-His-GQD-G was used as the nanozyme for colorimetric detection of chlorpyrifos. Co-His-GQD-G catalyzes oxidization of 3,3',5,5'-tetramethylbenzidine into blue product. Thiocholine produced by hydrolysis of acetylthiocholine under catalysis of acetylcholinesterase inhibits catalytic activity of Co-His-GQD-G and leads to a reduced oxidization rate. Chlorpyrifos inhibits activity of acetylcholinesterase and brings an enhanced absorbance of blue product. The absorbance at 652 nm linearly increases with increasing chlorpyrifos concentration in the range of 2-20 ng mL-1 with detection limit of 0.57 ng mL-1 (S/N = 3). The method was successfully applied in determination of chlorpyrifos in peach by preparing Co-His-GQD-G magnetic gel sheet.

Highly sensitive electrochemical detection of circulating tumor DNA in human blood based on urchin-like gold nanocrystal-multiple graphene aerogel and target DNA-induced recycling double amplification strategy.

Detection of circulating tumor DNA (ctDNA) is important approach to risk stratification and treatment response monitoring of cancer patients, but current method lacks of enough sensitivity and repeatability. The paper repors shape-controlled synthesis of gold nanocrystals via reduction of HAuCl4 with ascorbic acid. The synergy of CTAC, KBr, KI and L-glutathione creates urchin-like gold nanocrystals (U-Au) with more exposed high-index facets. Preparation of electrochemical sensing platform for ctDNA involves modification of U-Au-multiple graphene aerogel for target DNA-induced recycle amplification. DNA probe 1 (P1) with methylene blue (MB) hybridizes with DNA probe 2 with ferrocene (Fc) to form duplex DNA, which was attached to U-Au through Au-S bond. The ctDNA hybridizes with hairpin DNA 1 to open hairpin structure, triggering target DNA-induced recycle. Utilization of target DNA-induced recycling allows one target DNA to approach many MB probes to electrode surface and to leave many Fc probes from electrode surface, promoting significant signal amplification. The detection signal is enhanced by catalyzed redox of Fc and MB. Electrochemical response increases with ctDNA concentration from 0.1 to 1 × 106 fM with detection limit of 0.033 fM. The biosensor provides ultrahigh sensitivity, specificity and stability and was successfully applied in detection of ctDNA in human blood.

Molecular machine and gold/graphene quantum dot hybrid based dual amplification strategy for voltammetric detection of VEGF165.

Graphene quantum dots (GQDs) were prepared via pyrolysis of citric acid and glutamic acid, then reacted with chlorauric acid to form a gold/graphene quantum dot hybrid (Au/GQD), and finally connected with hairpin DNA probe 1 (H1) and thionine (Thi). The H1-Au/GQD-Thi composite is found to be a viable redox probe for electrochemical and aptamer-based determination of vascular endothelial growth factor VEGF165. A dual amplification strategy is employed based on the use of molecular machine and the Au/GQD. Each single VEGF165 molecule can bind two DNA probes via specific aptamer-target recognition to produce a molecular machine. Surface-tethered hairpin DNA 2 (H2) hybridizes with the molecular machine through proximity effect, and the prelocked toehold domain of H2 becomes exposed. This part binds to H1-Au/GQD-Thi to release the molecular machine which then moves to the neighboring H2 upon which a surface programmatic chain reaction is initiated. By continuous molecular machine travel, many H1-Au/GQD-Thi probes are present on the gold electrode surface. This implies an efficient signal amplification capability. The Au/GQD based redox probes in-situ catalyzes the redox activity of thionine and further enhances the detection signal. The aptasensor exhibits ultrahigh sensitivity and selectivity for VEGF165. The square wave voltammetric signal, best measured at -0.18 V vs. Ag/AgCl, increases linearly in the 1.0 fM to 120 pM VEGF165 concentration range, and the detection limit is 0.3 fM. Conceivably, the method may be applied to other target proteins if the corresponding high-affinity aptamers are available. Graphical abstract This study report one dual amplification strategy for ultrasensitive electrochemical detection of VEGF165 based on gold-graphene quantum dot hybrid (Au/GQD) and bipedal molecular machine (BMM) powered surface programmatic chain reaction (SPCR).

Pentaethylenehexamine and d-penicillamine co-functionalized graphene quantum dots for fluorescent detection of mercury(II) and glutathione and bioimaging.

Pentaethylenehexamine and d-penicillamine co-functionalized graphene quantum dots (PEHA-GQD-DPA) was made via one two-step thermal pyrolysis. The resulting PEHA-GQD-DPA is composed of the graphene sheets with an average size of 3.16 nm and the rich of functional groups. It gives an ultra strong fluorescence emission with the fluorescent quantum yield of 90.91% and sensitive and selective optical response towards Hg2+. The fluorescence intensity linearly decreases with the increase of Hg2+ in the range of 1.0 × 10-10-2 × 10-4 M with the detection limit of 4.6 × 10-11 M (S/N = 3). No species tested interfere with detection of Hg2+. The fluorescence quenched by Hg2+ can be well recovered by glutathione. The fluorescence intensity linearly increases with the increase of glutathione in the range of 5 × 10-8-2.5 × 10-6 M with the detection limit of 1.7 × 10-8 M (S/N = 3). The PEHA-GQD-DPA as a fluorescence probe has been successfully applied in determination of Hg2+ in natural water and glutathione in human serum and SW480 cell imaging.

Preliminary application of multiple parameters spectral CT in the diagnosis of ovarian cancer / 实用放射学杂志

Objective To evaluate the effectiveness of spectral CT with multiple parameters on the diagnosis of ovarian cancer. Methods The data of 22 patients with spectral CT enhanced scan were analyzed retrospectively.The patients were divided into two groups:ovarian cancer group (n=11)and benign tumor group (n=11),according to the pathologic results.CT values at 40 keV,iodine concentration (IC),water concentration(WC)and spectral curve slope (λHU)of arterial phase and venous phase in the tumors of two groups were measured with gemstone spectral imaging(GSI)post-processing software.The independent samples t test was used to compare these multiple parameters above between two groups.Interobserver agreement with regard to various parameters was assessed using Cohen’s Kappa . For the parameters which showed statistically different,the receiver operating characteristic(ROC)curves were further generated to calculate their diagnostic effectiveness respectively.Results CT values at 40 keV,IC andλHUmeasured in arterial and venous phases were higher in ovarian cancer group than those in benign tumor group.There were significant differences between these two groups(P<0.05). While WC had no significant difference in these two groups (P>0.05).Interobserver agreement with regard to various parameters was excellent (Kappa>0.80).CT values at 40 keV,IC andλHUhad high effectiveness on the diagnosis of ovarian cancer according to ROC curves.The optimal parameter among them was IC in arterial phase with AUC of 0.90.Using 10.92 (100 μg/cm3)as a threshold value,the sensitivity and specificity for diagnosis were 90.9% and 90.9%.Conclusion Spectral CT with multiple parameters,including CT values at 40 keV,IC and λHUhave significant differences between benign and malignant ovarian tumors.IC in arterial phase has the highest effectiveness on the diagnosis of ovarian cancer.

Improved activity and thermo-stability of the horse radish peroxidase with graphene quantum dots and its application in fluorometric detection of hydrogen peroxide.

Graphene quantum dots (GQDs) have received extensive concern in many fields such as optical probe, bioimaging and biosensor. However, few reports refer on the influence of GQDs on enzyme performance. The paper reports two kinds of graphene quantum dots (termed as GO-GQDs and N,S-GQDs) that were prepared by cutting of graphene oxide and pyrolysis of citric acid and l-cysteine, and their use for the horse radish peroxidase (HRP) modification. The study reveals that GO-GQDs and N,S-GQDs exhibit an opposite effect on the HRP performance. Only HRP modified with GO-GQDs offers an enhanced activity (more than 1.9 times of pristine enzyme) and thermo-stability. This is because GO-GQDs offer a larger conjugate rigid plane and fewer hydrophilic groups compared to N,S-GQDs. The characteristics can make GO-GQDs induce a proper conformational change in the HRP for the catalytic performance, improving the enzyme activity and thermo-stability. The HRP modified with green luminescent GO-GQDs was also employed as a biocatalyst for sensing of H2O2 by a fluorometric sensor. The colorless tetramethylbenzidine (TMB) is oxidized into blue oxidized TMB in the presence of H2O2 by the assistance of HRP/GO-GQDs, leading to an obvious fluorescence quenching. The fluorescence intensity linearly decreases with the increase of H2O2 concentration in the range from 2×10-9 to 2×10-4M with the detection limit of 6.8×10-10M. The analytical method provides the advantage of sensitivity, stability and accuracy compared with present H2O2 sensors based on the pristine HRP. It has been successfully applied in the determination of H2O2 in real water samples. The study also opens a new avenue for modification of enzyme activity and stability that offers great promise in applications such as biological catalysis, biosensing and enzyme engineering.

Synthesis of nitrogen-doped activated graphene aerogel/gold nanoparticles and its application for electrochemical detection of hydroquinone and o-dihydroxybenzene.

Graphene aerogel materials have attracted increasing attention owing to their large specific surface area, high conductivity and electronic interactions. Here, we report for the first time a novel strategy for the synthesis of nitrogen-doped activated graphene aerogel/gold nanoparticles (N-doped AGA/GNs). First, the mixture of graphite oxide, 2,4,6-trihydroxybenzaldehyde, urea and potassium hydroxide was dispersed in water and subsequently heated to form a graphene oxide hydrogel. Then, the hydrogel was dried by freeze-drying and reduced by thermal annealing in an Ar/H2 environment in sequence. Finally, GNs were adsorbed on the surface of the N-doped AGA. The resulting N-doped AGA/GNs offers excellent electronic conductivity (2.8 × 10(3) S m(-1)), specific surface area (1258 m(2) g(-1)), well-defined 3D hierarchical porous structure and apparent heterogeneous electron transfer rate constant (40.78 ± 0.15 cm s(-1)), which are notably better than that of previous graphene aerogel materials. Moreover, the N-doped AGA/GNs was used as a new sensing material for the electrochemical detection of hydroquinone (HQ) and o-dihydroxybenzene (DHB). Owing to the greatly enhanced electron transfer and mass transport, the sensor displays ultrasensitive electrochemical response to HQ and DHB. Its differential pulse voltammetric peak current linearly increases with the increase of HQ and DHB in the range of 5.0 × 10(-8) to 1.8 × 10(-4) M for HQ and 1 × 10(-8) to 2.0 × 10(-4) M for DHB. The detection limit is 1.5 × 10(-8) M for HQ and 3.3 × 10(-9) M for DHB (S/N = 3). This method provides the advantage of sensitivity, repeatability and stability compared with other HQ and DHB sensors. The sensor has been successfully applied to detection of HQ and DHB in real water samples with the spiked recovery in the range of 96.8-103.2%. The study also provides a promising approach for the fabrication of various graphene aerogel materials with improved electrochemical performances, which can be potentially applied in biosensors, electrocatalysis, and energy storage/conversion devices.

The study of dual energy spectral CT on the image quality of hand tendons / 实用放射学杂志

Objective To evaluate the image quality of hand tendons by using spectral CT,compared with conventional CT ima-ges.Methods Forty patients scanned with spectral CT were enrolled.The 65keV of optimal contrast-to-noise ratio (Optimal CNR) for viewing hand tendons was selected.The image quality of monochromatic GSI images (65 keV)and conventional CT images were compared with two different methods including subjective method and objective method by two radiologists respectively.Results In subjective method,the image quality in GSI images was superior to conventional CT images (P <0.05).And in objective method, the beam-hardening artifacts in the phalanges of fingers space were reduced markedly with hand tendons displaying more clearly in GSI images (P <0.05 ).There was no significant difference between the two radiologists in both methods with good correlation (Kappa=0.75,Kappa=0.85).Conclusion Spectral CT with the optimal 65keV monochromatic images could reduce the artifacts and increase image quality significantly in hand tendons imaging.It might be a very useful supplementary imaging method in detec-ting tendon diseases in routine work.

Quantitative low attenuation areas of every lung lobe assessment of pulmonary function loss by MDCT in COPD patients / 实用放射学杂志

Objective To determine the capability of quantitative low attenuation areas volume percentage(LAA%)in individual lobes to assess pulmonary function loss and disease severity in pulmonary COPD patients.Methods A total of 80 subjects (50 COPD patients;30 normal smokers),who all were smokers,underwent pulmonary function tests(PFTs)and Chest CT examination at full inspiration.For the quantitative assessment,percentage of low attenuation areas were automatically calculated for each lobe by the post processing software(Thoracic VCAR).To study the correlation between these CT parameters and lung function(FEV1% pre-dicted,FEV1/FVC,DLCO%predicted,RV/TLC),univariate linear regression analysis was performed.CT measurements were compared between the five groups with analysis of covariance(ANCOVA).Results FEV1 and FEV1/FVC had significant correla-tions with all of these CT parameters.DLCO、RV/TLC had significant correlations with these parameters,aside from the LAA% of right middle lobe and right inferior lobe.The LAA% in left upper lobe have the highest correlation with FEV1、DLCO、RV/TLC. However,FEV1/FVC have the highest correlation with the LAA% of right lower lobe.The LAA% of Right lung,right upper lobe,and whole lung were significantly different between the non-COPD group and GOLD1 group.Conclusion Whole lung and every lung lobe low attenuation areas volume percentage were reflected the lung function impairment in COPD patients.

Study on the relationship between blood T-lymphocyte subsets level and hepatitis B virus reactivation / 中国基层医药

Objective To investigate the relationship between hepatitis B virus reactivation and the level of blood T-lymphocyte subsets.Methods T lymphocyte subsets ( CD3,CD4,CDs ),CD4/CDs level of 40 patients with chronic carriers of hepatitis B virus and 35 patients with hepatitis B virus re-activation were detected by Flow cytometry(Epics XL).Results The hepatitis B virus reactivation in patients with CD3,CD4 and CD4/CDs levels were significantly lower than the chronic hepatitis B virus carriers,The difference between the two groups patients was significant[(71.31 ±5.20)％ vs (68.57 ±6.10)％,(37.82 ±4.90)％ vs (32.12 ±5.93)％,(1.37 ±0.28) vs (1.18 ±0.43 ),all P ＜ 0.05].Conclusion The levels of CD3,CD4 and CD4/CD8 ratio were significantly declined,it may be the one important reason of hepatitis B virus reactivation.

Comparison of the effects of fenofibrate and polyene phosphatidylcholine in the treatment of non-alcoholic fatty liver disease / 中国基层医药

Objective To investigate the clinical effects of fenofibrate and polyene phosphatidylcholine in treatment of non-alcoholic fatty liver disease.Methods 86 patients with non-alcoholic fatty liver disease were randomly divided into two groups.45 cases in therapy group received 0.2g of fenofibrate once a day,and the others in control group received 456mg of polyene phosphatidylcholine for three times per day.All of the patients were treated for 12 weeks.Liver function,blood fat,clinical effect and liver B ultrasonic were analyzed before treatment and after 12 weeks.Results The improvement of liver function,blood fat,and liver ultrasonic imaging in therapy group was better than that in the control group.The cure rate was 82.2％ in therapy group and 63.4％ in control group.There was a statistical significance between the two groups ( x2 =3.874,P ＜ 0.05).Conclusion Fenofibrate had significant therapeutic effect in treatment of non-alcoholic fatty liver disease with lower costs and lower side effects.

Advances of molecular imaging in staging of non-small cell lung cancer / 中国介入影像与治疗学

Molecular imaging technologies are newly emerging subjects in recent years, which are the medical research hotspots today. Advances of several common molecular imaging technologies in the staging of non-small cell lung cancer were reviewed in this article.

Discussion on many problems in bio-medical engineering discipline of higher learning institutions / 中华医学教育探索杂志

This paper analyzes many problems in bio-medical engineering curriculum of higher learning institution,expounds the status quo of curriculum set-up,incomplete curriculum structure,teaching team and laboratory construction and so on,points out experimental teaching mode based on optimization and integration of curriculum,combination of specific talents and specialized talents,standardization of laboratory construction,advocates experimental teaching mode based on student-centered and teacher-instructed mode,and discusses bio-medical engineering devlopment in 21st century under new technology and new materials.

Comparative Study of ~(18)F-FDG PET-CT and ~(99)T_c~m-MDP Bone Scan in Detecting Bone Metastases / 实用放射学杂志

Objective To compare the diagnostic value of PET-CT and bone scintigraphy in bone metastases. Methods Thirty-two patients with malignant neoplasm confirmed by pathology were undergone18F-FDG PET-CT and bone scan within two weeks.The sensitivity,specificity and accuracy of PET-CT and bone scan in detecting the focus were compared at the same scan filed.Results The diagnostic sensitivity,specificity and accuracy with PET-CT were 94.9%,91.7% and 94.1%,respectively,and 96.2%,54.2% and 86.3% with bone scan,respectively.18F-FDG PET-CT and99Tcm-MDP bone scan were the same in detecting metastatic tumor of bone,but the specificity of18F-FDG PET-CT was better than99Tcm-MDP bone scan in detecting bone metastasis.Conclusion Compared with99Tcm-MDP bone scan,18F-FDG PET-CT is more specific and helpful in detecting bone metastases.