Electrochemical Aptasensor for Myoglobin-Specific Recognition Based on Porphyrin Functionalized Graphene-Conjugated Gold Nanocomposites

In this work, a novel electrochemical aptasensor was developed for sensitive and selective detection of myoglobin based on meso-tetra (4-carboxyphenyl) porphyrin-functionalized graphene-conjugated gold nanoparticles (TCPP–Gr/AuNPs). Due to its good electric conductivity, large specific surface area, and excellent mechanical properties, TCPP–Gr/AuNPs can act as an enhanced material for the electrochemical detection of myoglobin. Meanwhile, it provides an effective matrix for immobilizing myoglobin-binding aptamer (MbBA). The electrochemical aptasensor has a sensitive response to myoglobin in a linear range from 2.0 × 10−11 M to 7.7 × 10−7 M with a detection limit of 6.7 × 10−12 M (S/N = 3). Furthermore, the method has the merits of high sensitivity, low price, and high specificity. Our work will supply new horizons for the diagnostic applications of graphene-based materials in biomedicine and biosensors

Influence Analysis of Geometric Error and Compensation Method for Four-Axis Machining Tools with Two Rotary Axes

Four-axis machine tools with two rotary axes are widely used in the machining of complex parts. However, due to an irregular kinematic relationship and non-linear kinematic function with geometric error, it is difficult to analyze the influence the geometry error of each axis has and to compensate for such a geometry error. In this study, an influence analysis method of geometric error based on the homogeneous coordinate transformation matrix and a compensation method was developed, using the Newton iterative method. Geometric errors are characterized by a homogeneous coordinate transformation matrix in the proposed method, and an error matrix is integrated into the kinematic model of the four-axis machine tool as a means of studying the influence the geometric error of each axis has on the tool path. Based on the kinematic model of the four-axis machine tool considering the geometric error, a comprehensive geometric error compensation calculation model based on the Newton iteration was then constructed for calculating the tool path as a means of compensating for the geometric error. Ultimately, the four-axis machine tool with a curve tool path for an off-axis optical lens was chosen for verification of the proposed method. The results showed that the proposed method can significantly improve the machining accuracy

Triple Amplification Ratiometric Electrochemical Aptasensor for CA125 Based on H‑Gr/SH-β-CD@PdPtNFs

A triple-amplified and ratiometric electrochemical aptasensor for CA125 was designed based on hemin–graphene/SH-β-cyclodextrin@PdPt nanoflower (H-Gr/SH-β-CD@PdPtNF) composites and an exonuclease I (Exo I)-assisted strategy. In the nanocomposite, hemin acts as an internal reference signal owing to the reversible heminox/heminred pair. PdPtNFs can significantly improve the electron transfer rate. SH-β-CD can efficiently enrich quercetin probes through host–guest recognition and increase the second indicator signal. In the presence of CA125, due to the specific binding between the aptamer and CA125, the conformational change of dsDNA (designed by the CA125 aptamer and its complementary DNA) results in the release of quercetin embedded in dsDNA. Subsequently, the free quercetin and DNA fragments are enriched on the H-Gr/SH-β-CD@PdPtNF-modified electrode. Thus, an enhanced oxidation peak from quercetin (IQ) and a reduced peak from hemin (Ihemin) can indicate the same biological identification event. In addition, the recycling amplification of CA125 by Exo I can effectively assist the increase of the quercetin signal. The value of IQ/Ihemin is linear with the concentration of CA125 in the range from 6.0 × 10–4 to 1.0 × 103 ng/mL, and the limit of detection is 1.4 × 10–4 ng/mL. The recovery of CA125 in human blood serum samples was from 99.2 to 104.4%. The proposed sensor is sensitive and reliable, which provides an avenue for the development of triple amplification and ratiometric signal strategies for detecting tumor markers in clinical diagnostics

Cold Atmospheric Plasma Activates Selective Photothermal Therapy of Cancer

Due to the body’s systemic distribution of photothermal agents (PTAs), and to the imprecise exposure of lasers, photothermal therapy (PTT) is challenging to use in treating tumor sites selectively. Striving for PTT with high selectivity and precise treatment is nevertheless important, in order to raise the survival rate of cancer patients and lower the likelihood of adverse effects on other body sections. Here, we studied cold atmospheric plasma (CAP) as a supplementary procedure to enhance selectivity of PTT for cancer, using the classical photothermic agent’s gold nanostars (AuNSs). In in vitro experiments, CAP decreases the effective power of PTT: the combination of PTT with CAP at lower power has similar cytotoxicity to that using higher power irradiation alone. In in vivo experiments, combination therapy can achieve rapid tumor suppression in the early stages of treatment and reduce side effects to surrounding normal tissues, compared to applying PTT alone. This research provides a strategy for the use of selective PTT for cancer, and promotes the clinical transformation of CAP

Toxicity Evaluation of Pig Slurry Using Luminescent Bacteria and Zebrafish

Biogas slurry has become a serious pollution problem and anaerobic digestion is widely applied to pig manure treatment for environmental protection and energy recovery. To evaluate environmental risk of the emission of biogas slurry, luminescent bacteria (Vibrio fischeri), larvae and embryos of zebrafish (Danio rerio) were used to detect the acute and development toxicity of digested and post-treated slurry. Then the ability of treatment process was evaluated. The results showed that digested slurry displayed strong toxicity to both zebrafish and luminescent bacteria, while the EC50 for luminescent bacteria and the LC50 for larvae were only 6.81% (v/v) and 1.95% (v/v) respectively, and embryonic development was inhibited at just 1% (v/v). Slurry still maintained a high level of toxicity although it had been treated by membrane bioreactor (MBR), while the LC50 of larvae was 75.23% (v/v) and there was a little effect on the development of embryos and V. fischeri; the results also revealed that the zebrafish larvae are more sensitive than embryos and luminescent bacteria to pig slurry. Finally, we also found the toxicity removal rate was higher than 90% after the treatment of MBR according to toxicity tests. In conclusion, further treatment should be used in pig slurry disposal or reused of final effluent

Antisense Transcription in the Human Cytomegalovirus Transcriptome▿ †

Human cytomegalovirus (HCMV) infections are prevalent in human populations and can cause serious diseases, especially in those with compromised or immature immune systems. The HCMV genome of 230 kb is among the largest of the herpesvirus genomes. Although the entire sequence of the laboratory-adapted AD169 strain of HCMV has been available for 18 years, the precise number of viral genes is still in question. We undertook an analysis of the HCMV transcriptome as an approach to enumerate and analyze the gene products of HCMV. Transcripts of HCMV-infected fibroblasts were isolated at different times after infection and used to generate cDNA libraries representing different temporal classes of viral genes. cDNA clones harboring viral sequences were selected and subjected to sequence analysis. Of the 604 clones analyzed, 45% were derived from genomic regions predicted to be noncoding. Additionally, at least 55% of the cDNA clones in this study were completely or partially antisense to known or predicted HCMV genes. The remarkable accumulation of antisense transcripts during infection suggests that currently available genomic maps based on open-reading-frame and other in silico analyses may drastically underestimate the true complexity of viral gene products. These findings also raise the possibility that aspects of both the HCMV life cycle and genome organization are influenced by antisense transcription. Correspondingly, virus-derived noncoding and antisense transcripts may shed light on HCMV pathogenesis and may represent a new class of targets for antiviral therapies

Geological features and exploration potential of Permian Tiaohu Formation tight oil, Santanghu Basin, NW China

Based on seismic data, logging, mud logging and lab testing data, the geological features and exploration potential of Permian Tiaohu Formation tight oil were studied in Santanghu Basin, Hami Area, Xinjiang. The tight sedimentary tuff characterized as high porosity and low permeability is developed in the second member of Tiaohu Formation in Santanghu Basin, and its granularity is fine, nano-scale pores and throats account for 88.3%, its permeability is lower than 0.5×10−3 μm2. Because of high brittleness, the reservoir rocks are easy to be fractured, and its oil saturation and crude oil density are high. The oil in tight sedimentary tuff is mainly from the underlying Permian Lucaogou Formation high-quality source rocks with a 100−500 m interval between source rocks and reservoirs. The crude oil generated in source rocks migrated up to the second member of Tiaohu Formation along faults and fractures characterized as other-sourced charging and source-reservoir separating. Tight oil distribution is mainly controlled by Lucaogou Formation source rocks and second member of Tiaohu Formation sedimentary tuff reservoirs. The area of “sweet spots” in the second member of Tiaohu Formation of Malang-Tiaohu Sag is about 203 km2, and the oil resource is predicted to be 2.4×108 t. Key words: Santanghu Basin, Tiaohu Formation, tight oil, sedimentary tuff, volcanic reservoi