Pressure-based bioassays incorporating biomolecular recognition with a catalyzed gas-generation reaction have been developed for gas biosensors, but most involve poor sensitivity and are unsuitable ...for routine use. Herein we design an innovative gas pressure-based biosensing platform for the detection of Kanamycin (Kana) on polyaniline nanowires-functionalized reduced graphene oxide (PANI/rGO) framework by using platinum nanozyme-catalyzed gas generation. The signal was amplified by coupling with catalytic hairpin assembly (CHA) and strand-displacement amplification (SDA). Upon target Kana introduction, the analyte initially triggered a SDA reaction between hairpin DNA1 and hairpin DNA2, and then induced CHA conjugation between magnetic bead-labeled hairpin DNA3 (MB–H3) and platinum nanoparticle-labeled hairpin DNA4 (Pt–H4) to form a three-dimensional network. Numerous platinum nanoparticles (peroxidase-like nanozymes) were carried over with magnetic beads to reduce hydrogen peroxide into oxygen. The as-produced gas compressed PANI/rGO frameworks (modified to polyurethane sponge, used as the piezoelectric materials) in a homemade pressure-tight device, thus causing the increasing current of PANI/rGO sponge thanks to its deformation. The change in the current caused by the as-generated gas pressure was determined on an electrochemical workstation. Under optimum conditions, PANI/rGO sponge exhibited outstanding compressibility, stable signal-waveform output, fast response and recovery time (≈109 ms), and the current increased with the increasing Kana concentration within a dynamic working range of 0.2–50 pM at a detection limit of 0.063 pM. Good reproducibility, specificity, and acceptable precision were acquired for Kana analysis. In addition, the accuracy of this method was monitored to evaluate real milk samples with the well-matched results obtained by using the referenced Kana ELISA kit.
This work reports a strategy for glutathione-loaded liposome-encoded magnetic beads initiated by palindromic fragment-mediated single-chain amplification (PFMSCA) for high-precision quantification of ...a low-abundance aminoglycoside antibiotic (kanamycin; Kana) by using In2O3–ZnIn2S4 (IO-ZIS) as a photoactive matrix. In this strategy, a Kana-recognition region, primer-like palindromic fragment, and polymerization/nicking template are reasonably integrated into one oligonucleotide (hairpin HP1) for target recognition, magnetic separation, and target amplification. Upon target Kana introduction, the Kana-aptamer region in HP1 specifically recognizes the Kana and triggers the palindromic tails intramolecular self-hybridization, amplifying a large number of short fragments in the presence of Klenow fragment polymerase and Nt.BbvCI. The as-generated nick fragments act as a linker to introduce the free hairpin HP2-functionalized glutathione-loaded liposomes (HP2-GLL) onto the surface of the hairpin HP3-modified magnetic beads (HP3-MB), constructing liposome-encoded magnetic beads (HP3-MB-nick-HP2-GLL). Following magnetic separation, the detached glutathione-loaded liposomes (GLL) are lysed by treatment with 1% Triton X-100 to release the glutathione within it, which were then detected as an amplified photocurrent at the IO-ZIS-based photoelectrode. Importantly, this method can be readily carried out by using one oligonucleotide to achieve an exponential amplification effect and open new opportunities for advanced development of robust biodetection systems.
This work presented an innovative and rationally engineered palindromic molecular beacon (PMB) based “Z-scheme” photoelectrochemical (PEC) biosensing protocol for the selective screening of kanamycin ...(Kana) through DNA hybridization-induced conformational conversion. Interestingly, the ingeniously designed PMB integrated the multifunctional elements including recognition region, primer-like palindromic fragment, and polymerization-nicking template. The cosensitized structures consisted of CdS quantum dot functionalized hairpin DNA2 (QD-HP2) and region-selectively deposited gold nanoparticles onto {001} facets of bismuth oxychloride (BiOCl-Au). Compared with BiOCl-Au alone, the attachment of CdS QDs onto BiOCl-Au (i.e., BiOCl-Au-CdS QDs) exhibited evidently enhanced photocurrent intensity thanks to the synergistic effect of Z-scheme BiOCl-Au-CdS QDs. After incubation with target Kana, Kana–aptamer binding could induce the exposure of PMB region for hairpin DNA1 (HP1). The exposed palindromic tails hybridized with each other (like a molecular machine) to consume the substrates (dNTPs) and fuels (enzyme) for the releasing of numerous nick fragments (Nick). The as-generated nick fragments could specifically hybridize with the complementary region of QD-HP2, thus resulting in decreasing photocurrent because of the increasing spatial distance for electron transfer between two-type photosensitizers. Under optimum conditions, the PMB-based sensing system exhibited satisfying photocurrent responses toward target Kana within the working range from 50 to 5000 fM at a low detection limit of 29 fM. Impressively, the concept of a palindromic fragment-mediated primer-free biosensing strategy offers a new avenue for advanced development of efficient and convenient biodetection systems.
Herein a versatile photoelectrochemical (PEC) bioanalysis platform for sensitive and specific screening of low-abundance antibiotics (kanamycin, Kana, used in this case) was innovatively designed ...using rGO-Bi2WO6-Au as photoactive matrix and target-induced branched hybridization chain reaction (t-bHCR) for efficient signal amplification. To realize the high-performance of our PEC bioanalysis system, rational introduction of reduced graphene oxide (rGO) and Au nanoparticles (Au NPs) greatly accelerated the electron transfer and enhances photoactivity. As expected, the ternary nanocomposite (i.e., rGO-Bi2WO6-Au) system with cascade energy level exhibited intense PEC signal responses thanks to multistep electron-transfer (MET) mechanism. Upon sensing the target Kana, t-bHCR is readily implemented, thus resulting in the assembly of numerous CuS nanoparticle (CuS NP). As a result, the loading CuS NPs from hyper-branched structure boosted the electron donors (ascorbic acid) consumption and enhanced the steric hindrance, synergistically decrease the photoelectric response. Under the optimized testing conditions, the t-bHCR-based PEC bioanalysis exhibited superior analytical performance with a linear range of 1 pM to 5 nM target Kana and limit of detection down to 0.78 pM. Additionally, favorable stability, great anti-interference ability and satisfactory accuracy for the analysis of actual samples were acquired. Impressively, the concept of t-bHCR-mediated provides an alternative to construct PEC bioanalysis and inspire more interest in the design of advanced PEC bioanalysis through nucleic acid-related signal amplification.
•A photoelectrochemical sensing platform was designed for detection of antibiotic residues.•Target-assisted branched hybridization chain reaction for the signal amplification.•The rGO-Bi2WO6-Au for enhancing PEC performance through MET channel.
Agricultural crop residue burning, including open field burning and burned as household fuel, is a significant emission source of primary fine particulate matter (PM2.5) and gaseous precursors of ...secondary PM2.5. However, limited information exists on emission characterization, environmental impact, and control measure of PM2.5 emitted from agricultural crop residue burning in China. In this study, laboratory simulation experiments were conducted to characterize emission factors of PM2.5 and PM2.5-bound chemical compositions from the burning of three typical agricultural crop residues (rice, wheat and corn straw). PM2.5-bound chemical compositions in our measurements include elemental carbon (EC) and organic carbon (OC), water-soluble ions (WSI), polycyclic aromatic hydrocarbons (PAHs) and alkyl-polycyclic aromatic hydrocarbons (APAHs). Emission factors of PM2.5 and PM2.5-bound EC, OC, WSI, PAHs and APAHs were 13.1, 1.38, 7.68, 1.40, 0.99 × 10−3 and 0.20 × 10−3 g kg−1 for rice straw, 6.2, 0.55, 2.93, 1.53, 0.85 × 10−3 and 0.22 × 10−3 g kg−1 for wheat straw, and 10.5, 0.94, 5.93, 1.53, 0.93 × 10−3 and 0.22 × 10−3 g kg−1 for corn straw, respectively. PM2.5 emissions from agricultural crop residue burning were estimated to be 1248, 1485, and 1826 Gg in 2003, 2008, and 2013, respectively. Environmental impacts resulted from open field burning of agricultural crop residue, including visibility impairment, air quality degradation (sometimes heavy haze pollution) and adverse health effects, were explored in this study. Furthermore, in order to ensure the attainment of good ambient air quality during the harvest season, some control measures, such as straw returning to soil, power generation, biogas production and animal feed supply etc., were proposed to prohibit open field burning of agricultural crop residue in China.
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•Emission factors of PM2.5, its precursors and chemical compositions from agricultural crop residue burning were characterized.•Emission inventories of primary PM2.5 from agricultural crop residue burning were evaluated.•Potential environmental impacts due to agricultural crop residue burning were explored.•Effective control measures about agricultural crop residue burning were proposed.
JavaScript has played a crucial role in web development, making it a primary tool for hackers to launch assaults. Although malicious JavaScript detection methods are becoming increasingly effective, ...the existing methods based on feature matching or static word embeddings are difficult to detect different versions and obfuscation of JavaScript code. To solve this problem, we present JSContana, a novel detection method that consists of adaptable context analysis and efficient key feature extraction. The key to our approach is context analysis based on dynamic word embeddings. We convert JavaScript code to syntax unit sequences with detailed information and get the real contextual representation of code by dynamic word embeddings. Furthermore, as a classification module in the method, TextCNN can effectively extract key features. To demonstrate the performance of the method, we have conducted extensive comparison experiments under five-fold cross-validation. Numerical results show that the method achieves 0.990 in AUC-score, and outperforms the state-of-the-art method by up to 3.5%.
This letter proposes and experimentally demonstrates a novel physical layer security method based on a piecewise chaotic permutation for orthogonal frequency division multiplexing (OFDM) passive ...optical networks. The piecewise parabolic chaotic map is adopted to generate chaotic permutation vectors, which enhance the physical layer security with a simple structure. An experiment with a 26.33-Gb/s encrypted optical OFDM signal is performed to demonstrate the proposed method. The results show good resistance against illegal optical network units and indicate that our method has the potential for use in secure optical access networks.
With the development of intelligent substations, inspection robots are widely used to ensure the safe and stable operation of substations. Due to the prevalence of grass around the substation in the ...external environment, the inspection robot will be affected by grass when performing the inspection task, which can easily lead to the interruption of the inspection task. At present, inspection robots based on LiDAR sensors regard grass as hard obstacles such as stones, resulting in interruption of inspection tasks and decreased inspection efficiency. Moreover, there are inaccurate multiple object-detection boxes in grass recognition. To address these issues, this paper proposes a new assistance navigation method for substation inspection robots to cross grass areas safely. First, an assistant navigation algorithm is designed to enable the substation inspection robot to recognize grass and to cross the grass obstacles on the route of movement to continue the inspection work. Second, a three-layer convolutional structure of the Faster-RCNN network in the assistant navigation algorithm is improved instead of the original full connection structure for optimizing the object-detection boxes. Finally, compared with several Faster-RCNN networks with different convolutional kernel dimensions, the experimental results show that at the convolutional kernel dimension of 1024, the proposed method in this paper improves the mAP by 4.13% and the mAP is 91.25% at IoU threshold 0.5 in the range of IoU thresholds from 0.5 to 0.9 with respect to the basic network. In addition, the assistant navigation algorithm designed in this paper fuses the ultrasonic radar signals with the object recognition results and then performs the safety judgment to make the inspection robot safely cross the grass area, which improves the inspection efficiency.
Background:
Cystic fibrosis (CF) is associated with worsening of depression and anxiety symptoms. Elexacaftor/tezacaftor/ivacaftor (Trikafta®), a cystic fibrosis transmembrane regulator (CFTR) ...modulator approved in 2019, significantly improves lung function, decreases pulmonary exacerbations, and improves quality of life. Studies are needed to evaluate the effects of Trikafta on symptoms of anxiety and depression.
Research Question:
Do adults with CF report a change in depression and anxiety symptoms after Trikafta initiation?
Study Design and Methods:
A retrospective chart review was conducted of patients with CF (n = 127) receiving care from January 2015 through February 2022. Data collected included demographics, annual PHQ-9 and GAD-7 scores, FEV1 percent predicted at each visit, BMI, consistency and timeline of Trikafta use, mental health diagnoses, counseling/psychotherapy use, psychiatric medication use, prescriber of psychiatric medications, number of psychiatric emergency department visits and psychiatric hospital admissions, and sleep disturbances.
Results:
Of the 127 patients screened for eligibility, 100 patients were included. Data collected yielded 563 PHQ-9, 563 GAD-7, and 560 ppFEV1 data points. No significant changes in average PHQ-9 or GAD-7 scores were found after Trikafta initiation or due to the COVID-19 pandemic. However, 22% of patients initiated or had a change in psychiatric medications, and patients with changes in psychiatric medications had significantly higher PHQ-9 and GAD-7 scores than patients not prescribed psychiatric medications. Trikafta use improved lung function by an average of 5.23% (p = 8.56e−08). Around a quarter (23%) of all patients reported sleep issues after initiating Trikafta.
Interpretation:
No significant changes in average PHQ-9 and GAD-7 scores were found after Trikafta initiation. A quarter of patients required a change in psychiatric medications, and significant differences in depression and anxiety scores were found between patients with a change in psychiatric medications and those not prescribed medication. Twenty-three percent of patients reported a prevalence of sleep issues after Trikafta initiation.
Carboxymethyl pachymaran (CMP) was treated via high-temperature and cellulase hydrolysis to obtain HTCMP, HTEC-24, and HTEC-48. The chemical structure and in vivo antitumor activities of the four ...types of CMPs were investigated. Compared with CMP (787.9 kDa), the molecular weights of HTCMP, HTEC-24, and HTEC-48 were decreased to 429.8, 129.9, and 68.6 kDa, respectively. The viscosities and particle sizes of the CMPs could also decrease with the decline in the molecular weights. All the CMPs showed antitumor abilities, but HTEC-24 exhibited the best activity. In the animal study, when curing the spleen and thymus, CMPs displayed immunomodulatory effects by increasing the secretion of IFN-γ and IL2 in mice. The CMPs also exerted an antitumor ability by regulating the gut microbiota in tumor-bearing mice. Our results established a foundation to develop an antitumor drug with CMP.
