Comparative pharmacokinetic study of Anisodamine Hydrobromide tablets and injection in septic acute lung injury rats.

Aim: We aimed to establish a sensitive LC-MS/MS method to analyze the pharmacokinetics of Ani HBr tablets and injection.Methods: Around 10 mmNH4Ac containing 0.1% formic acid and acetonitrile were used as the mobile phase. Acute lung injury in septic and normal rats, respectively, were administered Ani HBr tablets at doses of 12.5, 25 and 50 mg/kg and injection at doses of 4, 8 and 16 mg/kg, followed by extraction of the drugs from plasma using ethyl acetate for subsequent analysis.Results & conclusion: The method met the requirements for biological analysis. Ani HBr tablets absorbed slowly in rats with disease, tail vein administration was a more promising approach for treating septic acute lung injury.

[Box: see text].

[Pollution Characteristics and Source Apportionment of VOCs in Urban Areas of Shijiazhuang in Spring].

Samples of ambient volatile organic compounds （VOCs） were collected using SUMMA canisters at three Country Control Sites in Shijiazhuang during the spring of 2019, 2021, and 2022, which were detected using gas chromatography/mass spectrometry （GC/MS）. To investigate the characteristics and temporal variations of VOCs mass concentration levels, the online monitoring data of ozone （O3） and PM2.5 at the same site were also collected. Subsequently, the ozone formation potential （OFP） and secondary organic aerosol formation potential （SOAFP） were utilized to assess the chemical activity of VOCs. Additionally, the potential source areas of VOCs in spring in Shijiazhuang were further identified using the potential source contribution factor （PSCF） method and concentration weight trajectory analysis （CWT）. Hence, the major VOCs sources were evaluated with the VOCs initial mixing ratio. The results demonstrated that the averaged concentration of VOCs during the polluted period and clean period of spring in Shijiazhuang were 191.17 µg·m-3 and 122.18 µg·m-3, respectively. Meanwhile, the OFP was 361.23 µg·m-3 during the polluted period and 266.96 µg·m-3 during the clean period, whereas the SOAFP was 1.98 µg·m-3 and 1.61 µg·m-3, respectively. Therefore, effective control of benzene, toluene, ethylbenzene, and xylene （BTEX） is crucial for reducing PM2.5 and O3 pollution. Based on the results obtained from weight PSCF and CWT, the potential source areas of VOCs were further identified to be primarily located in the eastern Yuhua District, the high-tech district, and the northern Luancheng District of Shijiazhuang. These areas were influenced not only by local emissions but also by transport from neighboring regions, in which consistency between the CWT and PSCF results further supported these findings. Furthermore, the results obtained from the benzene/toluene/ethylbenzene （B/T/E） and xylene/benzene （X/B） ratios indicated that the main sources of VOCs in Shijiazhuang in spring were vehicle exhaust sources and burning sources, leading to a more serious air mass aging phenomenon. Hence, controlling vehicle emissions and implementing regional cooperative measures are the effective strategies for optimizing the air quality of Shijiazhuang.

Hypoxia-inducible factor-1α/vascular endothelial growth factor signaling pathway-based ulcer-healing mechanism of Astragalus Aqueous extract in diabetic foot rats.

The main objective of this work was to investigate the mechanism of Astragalus aqueous extract ulcer healing in diabetic foot model rats through the hypoxia-inducible factor 1-alpha (HIF-1ɑ)/vascular endothelial growth factor (VEGF) signalling pathway. Fifty specific-pathogen-free male Sprague Dawley rats were divided into blank (A), model control (B), Astragalus extract (C) and mupirocin (D) treatment groups. Group A received a regular diet, whereas the other groups received a high-fat/high-sugar diet and intraperitoneal streptozotocin injections to induce diabetes. Diabetic foot ulcers were created via skin excision. Subsequently, ulcers were debrided daily. Groups B, C and D received wet saline gauze, wet gauze with Astragalus extract and gauze with mupirocin, respectively, on the affected area. Group A received no treatment. After 14 days, the rats were assessed for ulcer healing and general condition. Immunohistochemistry was used to detect HIF-1ɑ and VEGF levels in the dorsalis pedis artery, and ELISA was used to determine serum IL-6 and CRP levels. The results revealed that Groups C and D had significantly faster ulcer healing compared with Group B (p < 0.01), and ulcer healing was faster in Group C than in Group D (p < 0.01). Group C exhibited notably higher HIF-1ɑ and VEGF protein expression levels compared with Groups B and D (p < 0.01). IL-6 and CRP expression levels in Groups C and D were significantly lower than those in Group B (p < 0.01). In summary, Astragalus aqueous extract effectively treats diabetic foot ulcers by up-regulating HIF-1ɑ and VEGF expression, activating the HIF-1ɑ/VEGF pathway, improving local tissue ischaemia and hypoxia, promoting collateral circulation and enhancing dorsalis pedis artery formation, thereby accelerating ulcer repair in diabetic rats.

Study on the Performance of Asphalt Modified with Bio-Oil, SBS and the Crumb Rubber Particle Size Ratio.

To enhance the properties of SBS and crumb rubber-modified asphalts, four different amounts (5%, 10%, 15%, and 20%) of castor oil were added to crumb rubber-modified asphalts to mitigate the adverse effects of high levels of fine crumb rubber particles on the aging resistance of SBS and crumb rubber-modified asphalt. Initially, a conventional test was conducted to assess the preliminary effects of bio-oil on the high-temperature and anti-aging properties of SBS and crumb rubber-modified asphalt. Subsequently, dynamic shear rheometer and bending beam rheometer tests were employed to evaluate the impact of bio-oil on the high- and low-temperature and anti-fatigue properties of SBS and crumb rubber-modified asphalt. Finally, fluorescence microscopy and Fourier transform infrared spectroscopy were used to examine the micro-dispersion state of the modifier and functional groups in bio-oil, SBS and crumb rubber composite-modified asphalts. The experimental results indicated that bio-oil increased the penetration of SBS and crumb rubber-modified asphalt, decreased the softening point and viscosity, and significantly improved its aging resistance. The addition of bio-oil enhanced the anti-fatigue properties of SBS and crumb rubber-modified asphalt. The optimal amount of added bio-oil was identified. Bio-oil also positively influenced the low-temperature properties of SBS and crumb rubber-modified asphalt. Although the addition of bio-oil had some adverse effects on the asphalt's high-temperature properties, the asphalt mixture modified with bio-oil, SBS, and crumb rubber still exhibited superior high-temperature properties compared to unmodified asphalt. Furthermore, fluorescence microscopy and Fourier transform infrared spectroscopy results demonstrated that bio-oil can be uniformly dispersed in asphalt, forming a more uniform cross-linked structure and thereby enhancing the aging resistance of SBS and crumb rubber-modified asphalt. The modification process involved the physical blending of bio-oil, SBS, and crumb rubber within the asphalt. Comprehensive research confirmed that the addition of bio-oil has a significant and positive role in enhancing the properties of SBS and crumb rubber-modified asphalt with different composite crumb rubber particle size ratios.

Kaempferol efficacy in metabolic diseases: Molecular mechanisms of action in diabetes mellitus, obesity, non-alcoholic fatty liver disease, steatohepatitis, and atherosclerosis.

The incidence of metabolic diseases has progressively increased, which has a negative impact on human health and life safety globally. Due to the good efficacy and limited side effects, there is growing interest in developing effective drugs to treat metabolic diseases from natural compounds. Kaempferol (KMP), an important flavonoid, exists in many vegetables, fruits, and traditional medicinal plants. Recently, KMP has received widespread attention worldwide due to its good potential in the treatment of metabolic diseases. To promote the basic research and clinical application of KMP, this review provides a timely and comprehensive summary of the pharmacological advances of KMP in the treatment of four metabolic diseases and its potential molecular mechanisms of action, including diabetes mellitus, obesity, non-alcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH), and atherosclerosis. According to the research, KMP shows remarkable therapeutic effects on metabolic diseases by regulating multiple signaling transduction pathways such as NF-κB, Nrf2, AMPK, PI3K/AKT, TLR4, and ER stress. In addition, the most recent literature on KMP's natural source, pharmacokinetics studies, as well as toxicity and safety are also discussed in this review, thus providing a foundation and evidence for further studies to develop novel and effective drugs from natural compounds. Collectively, our manuscript strongly suggested that KMP could be a promising candidate for the treatment of metabolic diseases.

Synergistic effects of hydrophilic function group and micropores on water evaporation in a novel carbon hydrogels for efficient solar steam generation.

Solar steam generation (SSG) using hydrogels is emerging as a promising technology for clean water production. Herein, a novel oxygen-doped microporous carbon hydrogel (OPCH), rich in hydrophilic groups and micropores, has been synthesized from microalgae to optimize SSG. OPCH outperforms hydrogels with hydrophobic porous carbon or nonporous hydrophilic biochar, significantly reducing water's evaporation enthalpy from 2216.06 to 1107.88 J g-1 and activating 42.3 g of water per 100 g for evaporation, resulting in an impressive evaporation rate of 2.44 kg m-2 h-1 under one sun. A detailed investigation into the synergistic effects of hydrophilic groups and micropores on evaporation via a second derivative thermogravimetry method revealed two types of bonded water contributing to enthalpy reduction. Molecular dynamics simulations provided further insights, revealing that the hydrophilic micropores considerably decrease both the number and the lifetime of hydrogen bonds among water molecules. This dual effect not only reduces the energy barrier for evaporation but also enhances the kinetic energy needed for the phase transition, significantly boosting the water evaporation process. The sustained high evaporation rates of OPCH, observed across multiple cycles and under varying salinity conditions, underscore its potential as a highly efficient and sustainable solution for SSG applications.

[Pollution Characteristics and Transport contributions of Ambient Ozone and Volatile Organic Compounds in Southern Hebei Cities].

The "14th Five-Year Plan" period is the key stage for southern Hebei cities (Shijiazhuang, Xingtai, and Handan) to be removed from the bottom ten of the Air Quality Composite Index. The hourly ozone (O3) data of 15 country-controlled monitoring stations in the southern cities of Hebei Province from April to October 2020, hourly data of three volatile organic compound (VOCs) supersites, and the meteorological data of the same period were used for analysis, combined with the spatiotemporal succession, O3 formation potential (OFP), backward trajectory modeling, and spatial statistical modeling. The results showed the following:firstly, the temporal variations in O3 in southern cities of Hebei Province from April to October presented an inverted "U" shape, and the spatial distribution was high in the south and low in the north. O3 pollution was the most serious in June, with Xingtai (233.8 µg·m-3)>Handan (225.2 µg·m-3)>Shijiazhuang (224.8 µg·m-3). O3 was positively correlated with temperature and wind speed and negatively correlated with humidity and VOCs; furthermore, the ρ(TVOC) from April to October followed the order of Xingtai (274 µg·m-3)>Shijiazhuang (266 µg·m-3)>Handan (218 µg·m-3). The total OFP of alkenes and aromatics accounted for more than half; moreover, the trajectory of O3 pollution in southern cities of Hebei Province showed spatial directionality and relevance. The highest mass concentration of O3 (198.92 µg·m-3) was in the trajectory from Shijiazhuang to Xingtai, and the highest frequency of O3 pollution was in the trajectory from Handan to Xingtai. Moreover, the transmission contributions of O3from Xingtai to Shijiazhuang agglomerations were high (27.39%), and Handan played a significant role in the transmission contribution of O3 to Xingtai (32.76%).

Effects of silicate application on rice growth, yield and quality under nighttime warming in southern China.

The main feature of climate warming is that nighttime warming is higher than the daytime warming. Nighttime warming reduced single rice production in southern China, while silicate application increased rice yield and stress resistance. It is still unclear regarding the effects of silicate application on growth, yield, and especially quality in rice under nighttime warming. We performed a field simulation experiment to investigate the effects of silicate application on tiller number, biomass, yield and quality of rice. Warming was set at two levels, ambient temperature (control, CK) and nighttime warming (NW). The open passive nighttime warming method was used, with rice canopy being covered with aluminum foil reflective film at night (19:00-6:00) to simulate nighttime warming. Silicate fertilizer (steel slag) was applied at two levels, i.e., Si0(0 kg SiO2·hm-2) and Si1(200 kg SiO2·hm-2). The results showed that, compared with the control (ambient temperature), average temperature at nighttime on rice canopy and at 5 cm soil layer increased by 0.51-0.58 ℃ and 0.28-0.41 ℃ during rice growing season, respectively. Nighttime warming decreased tiller number and chlorophyll content by 2.5%-15.9% and 0.2%-7.7%, respectively. In contrast, silicate application increased tiller number and chlorophyll content by 1.7%-16.2% and 1.6%-16.6%, respectively. Under nighttime warming, silicate application increased dry weight of shoot, total dry weight of the whole plant, and yield at grain filling-maturity stage by 64.1%, 55.3%, and 7.1%, respectively. Under nighttime warming, silicate application significantly increased milled rice rate, head rice rate, and total starch content by 2.3%, 2.5%, and 41.8%, respectively. Nighttime warming reduced rice yield by decreasing the number of effective panicles, seed setting rate, and 1000-grain weight, but increasing empty grains. Silicate application increased rice yield by increasing the number of effective panicles, filled grains per panicle, seed setting rate and 1000-grain weight, but reducing empty grains. In conclusion, silicate application could effectively alleviate the suppressive effects of nighttime warming on growth, yield, and quality of single rice in Southern China.

Research on Confinement Effect of the Outer Steel Tube in Notched Square CFST Columns.

The outer steel tube in a concrete-filled steel tubular (CFST) column confines the core concrete and improves the compressive strength of the core concrete. When there is a notch damage in the tube, the confinement effect may be affected. The confinement effects of the notched steel tube in rectangular CFST columns were systematically investigated by using numerical approaches. Refined three-dimensional finite element models with advanced concrete constitutive relations were established. With the verified finite element modeling method, full-sized square CFST columns with horizontal, vertical, or diagonal notches at different locations of the steel tube were simulated. Stress distributions and deformation modes of the steel tube and core concrete were analyzed. Columns with a horizontal notch at the plate center location displayed a higher axial strength reduction than those with vertical notches. A parametric study was performed to investigate the influences of concrete strengths, steel strengths, steel ratios, notch length to column width ratios, and notch angles on the compressive strengths of the rectangular CFST columns. A practical design formula was proposed based on the obtained results. The proposed formula could effectively predict the influences of different notches on the confinement effect in the notched CFST columns.

A dual-signal electrochemical immunosensor for the detection of HPV16 E6 oncoprotein based on PdBP dendritic ternary nanospheres and MBSi-Chi nanocomposites.

Cervical cancer is a common cancer in women. HPV16 E6 oncoprotein is a reliable biomarker for cervical cancer. Although there are other methods for detecting E6 oncoprotein, the electrochemical method has more advantages, such as low cost, convenience and speed. In this study, a novel dual-signal electrochemical immunosensor for quick and sensitive detection of E6 oncoprotein based on a high efficiency catalyst and signal label was developed. Herein, to achieve quick detection, palladium-boron-phosphorus dendritic ternary nanospheres (PdBP NSs) not only acted as a catalyst to catalyze H2O2, but also as a support material to capture antibodies. Moreover, to realize sensitive detection, nanocomposites of mesoporous silica nanoparticles loaded with methylene blue and coated with chitosan (MBSi-Chi) were synthesized as a signal label, which can produce electrochemical signal. Under optimal conditions, the label-free immunosensor exhibited a linear range of 100 fg mL-1 to 4 ng mL-1 with a detection limit of 72.8 fg mL-1 (S/N = 3), and the sandwich-type immunosensor presented a linear range of 50 fg mL-1 to 4 ng mL-1 with a detection limit of 34.1 fg mL-1 (S/N = 3). The as-prepared dual-signal immunosensor had desirable specificity, stability and repeatability, implying its potential applications in clinical laboratory.

Enzyme-induced multicolor colorimetric and electrochemiluminescence sensor with a smartphone for visual and selective detection of Hg2.

In this study, we developed a novel dual-analytical platform for the visual, sensitive, and reliable analysis of mercury ions (Hg2+) in environmental water samples. Importantly, thymine (T)-rich DNA probes were utilized to form T-Hg2+-T base pairs in the presence of Hg2+ to ensure the specificity of the method. We synthesized new luminescent tris(4,4'-dicarboxylicacid-2,2'-bipyridyl) ruthenium (II) dichloride (Ru(dcbpy)32+)-modified metal-polydopamine frameworks (MPFs@Ru), which were then applied to construct an electrochemiluminescence (ECL) system for the first time, and it achieved accurate and sensitive quantitative detection of Hg2+. To achieve rapid on-site determination, a multicolorimetric system based on a smartphone was established by inducing deposition of silver shells on gold nanorods (Au NRs). Under optimized conditions, the dual-modal assay showed an excellent response for Hg2+ in the linear range of 2 pmol L-1 to 500 nmol L-1, with a low detection limit of 0.32 pmol L-1. Moreover, the proposed method demonstrated satisfactory selectivity, stability, and acceptable reproducibility for the detection of Hg2+. The recovery of lake water samples ranged from 98.53% to 111.97% for the ECL method and from 95.04% to 106.11% for the colorimetric method, indicating the potential applicability of the proposed method for monitoring environmental water samples.

DNAzyme assisted recycling amplification method for ultrasensitive amperometric determination of lead(II) based on the use of a hairpin assembly on a composite prepared from nitrogen doped graphene, perylenetetracarboxylic anhydride, thionine and gold nanoparticles.

A Pb(II)-DNAzyme is used in an amperometric method for the determination of Pb(II). The method is based on two feedback processes. In the first, the Pb(II)-DNAzyme initiates a reaction in presence of Pb(II) in a micro-tube to release a linear DNA (S1). In the second, the S1 triggers the recycling amplification between two types of hairpin-shaped DNA templates (H1 and H2) which consist of a primer sequence and a Pb(II)-DNAzyme substrate sequence. The Pb(II)-DNAzyme has excellent cleavage specificity toward the substrate sequence in S1 that combined firstly with H1 and then is linked to H2. This process will connect H1 and H2. After hybridization with H1 and H2 to form two DNA complexes, S1 is released and initiates the next recycling process. This results in efficient amplification. A glassy carbon electrode (GCE) was immersed into solution of HAuCl4 to electrodeposit a layer of gold nanoparticles. This is followed by the assembly of the hairpin probe H1 on the GCE. In addition, a nanohybrid consisting of 3, 4, 9, 10-Perylenetetracarboxylic acid (PTCA) and nitrogen-doped graphene (NG) was loaded with electroactive thionine (Thi) and gold to form nanoparticles of type NG-PTCA-Thi-Au. This is responsible for generating the amperometric signal (best measured at around -0.30 V vs. SCE) and also acts as the reducing agent for synthesizing the NG-PTCA-Thi-Au nanohybrid. H2 is immobilized on NG-PTCA-Thi-Au to form a new tracer label. The concentration of Pb(II) in a solution can be quantified by determination of the amount of cleaved S1. The method has high sensitivity and selectivity for Pb(II). The detection limit is 0.42 pM (S/N = 3), and the detection range extends from 1 pM to 1000 nM. Graphical abstract Schematic representation of electrodes for the determination of the lead ions (Pb2+). The sensor is using Pb2+-DNAzyme assisted recycling amplification based on hairpin assembly on a composite prepared from nitrogen doped graphene, perylenetetracarboxylic anhydride, thionine and gold nanoparticles (NG-PTCA-Thi-Au). This versatile platform expands studies on the detection of heavy metal ions.

A novel sandwich aptasensor for detecting T-2 toxin based on rGO-TEPA-Au@Pt nanorods with a dual signal amplification strategy.

T-2 toxin is a mycotoxin that can cause chronic illnesses, and the detection of T-2 toxin in food is critical for human health. Herein, a novel sandwich aptasensor with a dual signal amplification strategy was developed for the detection of T-2 toxin. Molybdenum disulfide-polyaniline-chitosan-gold nanoparticles (MoS2-PANI-Chi-Au) were processed to the modified glassy carbon electrode (GCE) and used as the aptasensor platform to expedite the electronics transport and immobilize the amino-terminated capture DNA probe by Au-N bonds. The reduced graphene oxide-tetraethylene pentamine-gold@platinum nanorods (rGO-TEPA-Au@Pt NRs) were first synthesized and immobilized with a signal DNA probe. Once T-2 toxin was added into the biosensing system, the aptamer would trap T-2 toxin to turn the signal off. Next, dissociative aptamer hybridized with the capture DNA probe in GCE and linked simultaneously to the signal DNA probe on rGO-TEPA-Au@Pt NRs with another end sequence of aptamer to turn the signal on. Owing to the efficient catalytic ability of bimetallic Au@Pt nanorods, the signal was perfectly amplified through the catalysis of hydrogen peroxide (H2O2) and recorded by chronoamperometry. With the outstanding augment response, the limit of detection reached 1.79 fg mL-1 (3SB/m) and a wide linear range from 10 fg mL-1 to 100 ng mL-1 was presented. The sensitivity of the aptasensor was 19.88 µA⋅µM-1⋅cm-2. Meanwhile, the DNA aptamer-bimetallic nanorod based sensing system presented excellent specificity. The developed aptasensor provides a new platform for T-2 toxin detection with low cost for real sample assays.

Behavior of an Advanced Bolted Shear Connector in Prefabricated Steel-Concrete Composite Beams.

The high-strength bolt shear connector in prefabricated concrete slab has advantages in applications as it reduces time during the construction of steel-concrete composite building structures and bridges. In this research, an innovative and advanced bolt shear connector in steel-concrete composite structures is proposed. To investigate the fundamental mechanical behavior and the damage form, 22 static push-off tests were conducted with consideration of different bolt dimensions, the reserved hole constraint condition, and the dimension of slab holes. A finite element (FE) model was established and verified by using test results, and then the model was utilized to investigate the influence of concrete strength, bolt dimension, yield strength, bolt pretension, as well as length-to-diameter ratio of high strength bolts on the performances of shear connectors. On the basis of FE simulation and test results, new design formulas for the calculation of shear resistance behavior were proposed, and comparisons were made with current standards, including AISC, EN 1994-1-1, GB 50017-2017, and relevant references, to check the calculation efficiency. It is confirmed that the proposed equation is in better agreement with the experimental results.

Dandelion-like CuO microspheres decorated with Au nanoparticle modified biosensor for Hg2+ detection using a T-Hg2+-T triggered hybridization chain reaction amplification strategy.

We fabricate a novel electrochemical biosensor based on the specific thymine-Hg2+-thymine (T-Hg2+-T) base pair for the highly sensitive detection of mercury ions (Hg2+) and utilize toluidine blue (TB) as a redox indicator that is combined with a hybridization chain reaction (HCR) for signal amplification. The dandelion-like CuO (D-CuO) microspheres that were assembled using Au nanoparticles were first introduced as support materials, which produced more active sites for the thiolated probe (P1) combination. Then, the presence of Hg2+ induced P1 to hybridize with the other oligonucleotide (P2) through Hg2+-mediated T-Hg2+-T complexes. In addition, the partial sequence of P2 acted as an initiator sequence, which led the two hairpin DNA (H1 and H2) strands to collectively form the extended double-strand DNA through the HCR process on the electrode surface. TB was employed to interact with the double strands and produce an efficient electrochemical signal. The proposed strategy combined the amplification of the HCR and the inherent redox activity of TB and utilized D-CuO/Au composites, which exhibited high sensitivity for Hg2+ determination. Under the optimum conditions, the proposed biosensor showed a prominent response for Hg2+, including a linear range from 1 pM to 100 nM and a detection limit of 0.2 pM (S/N = 3). Moreover, the new biosensor proved its potential application for trace Hg2+ determination in environmental water samples.

Fabrication of pioneering 3D sakura-shaped metal-organic coordination polymers Cu@L-Glu phenomenal for signal amplification in highly sensitive detection of zearalenone.

Low molecular weight pollutants from foods have aroused global attention due to their toxicity after long-time exposure. There is an increased demand for appropriate methods to detect these pollutants in foods. In this study, a brand-new type of nano metal-organic coordination polymers (MOCPs) nanocarriers (3D sakura-shaped copper (II) ions@L-glutamic acid (L-Glu)) has been first synthesized. We herein demonstrate a facile chelated method that allows the combination of copper (II) ions and L-Glu. A series of controlled experiments have revealed that the reaction time and the ratio of reactants played the crucial roles in affecting the morphology of the final product. 3D sakura-shaped Cu@L-Glu combined with palladium-platinum nanoparticle (Pd-PtNPs) to obtain Cu@L-Glu/Pd-PtNPs acting as the signal tag, which applied in electrochemical aptasensor for ultrasensitive detection of zearalenone (ZEN). A glassy carbon electrode was first modified with spherical Au-PANI-Au nanohybrids to enhance the conductivity and immobilize more amino modified ZEN aptamer. Cu@L-Glu/Pd-PtNPs were labeled with Complementary DNA (partial matching with ZEN aptamer) to form bioconjugates for signal amplification. After the hybridization reaction of ZEN aptamer and the bioconjugates, a significant electrochemical signal from the catalysis of H2O2 by Cu@L-Glu/Pd-PtNPs can be observed. ZEN competed with bioconjugates for binding to ZEN aptamer, resulting in decreased the electrochemical signal. Chronoamperometry was applied to record the final electrochemical signals. Under optimal conditions, the electrochemical aptasensor exhibited desirable sensitive detection of ZEN with a wide linearity ranging from 1 fg/mL to 100 ng/mL and a relatively low detection limit of 0.45 fg/mL (S/N = 3). Furthermore, the proposed electrochemical aptasensor shows excellent selectivity to the ZEN in the presence of possible interfering substances, and has potential application for ZEN detection in food samples.

A palladium-platinum bimetal nanodendritic melamine network for signal amplification in voltammetric sensing of DNA.

A sandwich-type electrochemical DNA sensor is described for the detection of oligonucleotides typical for MECP2 gene mutations. Palladium nanoparticles (PdNPs) and platinum nanoparticles (PtNPs) were used to synthesize flower-like PdPt nanodendrites (NDs) by a one-pot method. The PdPt NDs possess a high specific surface area and excellent catalytic capabilities. They served as the carrier for the signal DNA probe (SP) and simultaneously catalyze the reduction of hydrogen peroxide (H2O2). The PdPt NDs were modified with melamine, and this results in the formation of a PdPt-melamine network through stable interactions between the PdPt NDs and the three amino groups of each melamine molecule. The network exhibits excellent catalytic ability in enhancing the current signal response in the voltammetric detection of MECP2 gene mutation, best measured at -0.4 V vs. SCE and using H2O2 as the electrochemical probe. In addition, gold nanoflowers were electrodeposited on the electrode interface in order to accelerate electron transfer and to capture the capture probe. The sensor is stable and can detect MECP2 gene mutations in the 1 fmol·L-1 to 1 nmol·L-1 concentration range, with a 0.33 fmol·L-1 lower detection limit at an S/N ratio of 3. Graphical abstract Schematic presentation of electrodes for the determination of the X-linked gene methyl-CpG-binding protein 2 (MECP2). The sensor is based on the electrooxidation of added H2O2 by using the melamine modified palladium platinum bimetal nanodendrites as network signal amplification strategy. This versatile platform expands studies on the detection of monogenic disease.

Target triggered cleavage effect of DNAzyme: Relying on Pd-Pt alloys functionalized Fe-MOFs for amplified detection of Pb2.

We designed an amplified detection strategy for the sensitive determination of lead ions (Pb2+) based on a target-triggered nuclear acid cleavage of Pb2+-specific DNAzyme as a selectivity interface combined with Pd-Pt alloys modified Fe-MOFs (Fe-MOFs/PdPt NPs) hybrids acting as the signal tag. Streptavidin modified reduced graphene oxide-tetraethylene pentamine-gold nanoparticles (rGO-TEPA-Au) served as a sensor platform for immobilizing more DNAzyme. In the presence of Pb2+, the substrate DNA strand can be specifically cleaved at the ribonucleotide site by DNAzyme to produce a new single-DNA on the interface. Then, the hairpin DNA with hybrid strand matched by its complement to the single-DNA was employed to modify the Fe-MOFs/PdPt NPs bioconjugates for signal amplification. Fe-MOFs/PdPt NPs catalyze hydrogen peroxide (H2O2) to produce the electrochemical signal which was recorded by chronoamperometry. Benefiting from the Pb2+-dependent DNAzyme, the proposed method can selectively detect Pb2+ in the presence of other metal ions. The newly designed biosensor exhibited a good linear relationship ranging from 0.005 to 1000nmolL-1 with a low detection limit of 2pM (S/N = 3) for Pb2+. This Pb2+-dependent DNAzyme based ultrasensitive biosensor showed high sensitivity and selectivity, providing potential application for Pb2+ detection in naturally contaminated sewage and spiked drinking water samples.

A novel non-invasive detection method for the FGFR3 gene mutation in maternal plasma for a fetal achondroplasia diagnosis based on signal amplification by hemin-MOFs/PtNPs.

The small amount of cell-free fetal DNA (cffDNA) can be a useful biomarker for early non-invasive prenatal diagnosis (NIPD) of achondroplasia. In this study, a novel non-invasive electrochemical DNA sensor for ultrasensitive detecting FGFR3 mutation gene, a pathogenic gene of achondroplasia, based on biocatalytic signal materials and the biotin-streptavidin system are presented. Notably encapsulation of hemin in metal-organic frameworks-based materials (hemin-MOFs) and platinum nanoparticles (PtNPs) were used to prepare hemin-MOFs/PtNPs composites via a one-beaker-one-step reduction. We utilized hemin-MOFs/PtNPs for signal amplification because the promising hemin-MOFs/PtNPs nanomaterial has remarkable ability of catalyze H2O2 as well as excellent conductivity. To further amplify the electrochemical signal, reduced graphene oxide-tetraethylene pentamine (rGO-TEPA), gold nanoparticles and streptavidin were selected for modification of the electrode to enhance the conductivity and immobilize more biotin-modified capture probe (Bio-CP) through the high specificity and superior affinity between streptavidin and biotin. The electrochemical signal was primarily derived from the synergistic catalysis of H2O2 by hemin and PtNPs and recorded by Chronoamperometry. Under the optimal conditions, this newly designed biosensor exhibited sensitive detection of FGFR3 from 0.1fM to 1nM with a low detection limit of 0.033fM (S/N=3). We proposed that this ultrasensitive biosensor is useful for the early non-invasive prenatal diagnosis of achondroplasia.

Effects of calcium oxide on the surface properties of municipal wastewater sludge and its co-slurrying ability with coal.

Urbanization has generated large volumes of municipal wastewater sludge (sludge for short) that threaten the environment and human health. As such, utilization of the sludge in a cost-effective manner is an important concern. The sludge, as a carbon-containing material, can be made into coal-sludge slurry (CSS) by mixing it with pulverized coal. However, the slurryability of the raw sludge is relatively poor due to the abundance of hydrophilic groups in the sludge and its loose floc structure. In this study, modification of the sludge with calcium oxide (CaO) showed positive effects on the sludge slurryability. The characteristic viscosity of the coal raw-sludge slurry (R-CSS) was 1635.3 mPa s. After modification of the sludge with 2 wt.% CaO for 24 h, the CSS viscosity decreased to 1184.4 mPa s. The hydrophobic group (CC and CH) content of the sludge increased from 61.5% to 74.9% as the CaO dosage increased from 0% to 4%, and the zeta potential increased from -55.1 eV to -36.2 eV. The optimum CaO dosage for improved slurryability was found to be 2 wt.%. Compared with R-CSS, the coal modified-sludge slurry (M-CSS) showed lower yield stress, weaker pseudoplastic and thixotropic behaviors, and poorer static stability.