Self-assembled coating with a metal-polyphenolic network for intraocular lens modification to prevent posterior capsule opacification.

Posterior capsule opacification (PCO) is a main complication after cataract surgery and intraocular lens (IOLs) implantation and is attributed to residual lens epithelial cells (LECs) migrating to the IOL surface and posterior capsules. IOL surface modification has been a newly-developing research filed in recent years; however, the applicability and economical acquisition of modified materials remain unsolved. In this study, we first applied a metal-polyphenolic network coating with a self-assembly technique on the IOL surface by using tannic acid (TA) combined with AlCl3, which are easily acquire and applying on the IOL surface to solve the IOL transmittance affair. Using wound healing and Transwell assay to verify AZD0364 inhibits cell migration (P< 0.05), the lipopolysaccharide-induced macrophage inflammation model to verify pterostilbene (PTE) inhibits the inflammatory reaction (P< 0.01). By optimizes its self-assembly coating parameters and calculating its drug release kinetics, we successfully loaded these two drugs on the coating, named TA (AZD0364/PTE) IOL. Its surface morphology characteristics were analyzed by scanning electron microscope, x-ray photoelectron spectrometer and water contact angle. The optical performance was carefully investigated by optical instruments and equipment (n= 3). Thein vitroresults showed that TA (AZD0364/PTE) IOL can significantly inhibit cell adhesion and acute inflammation (n= 3,P< 0.0001). Importantly, afterin vivoimplantation for 28 d with eight rabbits PCO models in two groups, the TA (AZD0364/PTE) IOL group maintained clear refracting media and decreased the inflammatory reaction compared with the original IOL group (P< 0.05). This study provides a new applicable and economical strategy for preventing PCO and offers a reference for the next generation of IOLs that benefit cataract patients.

Deep learning analysis for rapid detection and classification of household plastics based on Raman spectroscopy.

The overuse of plastics releases large amounts of microplastics. These tiny and complex pollutants may cause immeasurable damage to human social life. Raman spectroscopy detection technology is widely used in the detection, identification and analysis of microplastics due to its advantages of fast speed, high sensitivity and non-destructive. In this work, we first recorded the Raman spectra of eight common plastics in daily life. By adjusting parameters such as laser wavelength, laser power, and acquisition time, the Raman data under different acquisition conditions were diversified, and the corresponding Raman spectra were obtained, and a database of eight household plastics was established. Combined with deep learning algorithms, an accurate, fast and simple classification and identification method for 8 types of plastics is established. Firstly, the acquired spectral data were preprocessed for baseline correction and noise reduction, Then, four machine learning algorithms, linear discriminant analysis (LDA), decision tree, support vector machine (SVM) and one-dimensional convolutional neural network (1D-CNN), are used to classify and identify the preprocessed data. The results showed that the classification accuracy of the three machine learning models for the Raman spectra of standard plastic samples were 84%, 93% and 93% respectively. The 1D-CNN model has an accuracy rate of up to 97% for Raman spectroscopy. Our study shows that the combination of Raman spectroscopy detection techniques and deep learning algorithms is a very valuable approach for microplastic classification and identification.

SERS and machine learning based effective feature extraction for detection and identification of amphetamine analogs.

Surface-enhanced Raman spectroscopy (SERS) is extensively researched in diverse disciplines due to its sensitivity and non-destructive nature. It is particularly considered a potential and promising technology for rapid on-site screening in drug detection. In this investigation, a technique was developed for fabricating nanocrystals of Ag@Au SNCs. Ag@Au SNCs, as the basic material of SERS, can detect amphetamine at concentrations as low as 1 µg/mL. The Ag@Au SNCs exhibits a strong surface plasmon resonance effect, which amplifies molecular signals. The SERS spectra of ten substances, including amphetamine and its analogs, showed a strong peak signal. To establish a qualitative distinction, we examined the Raman spectra and conducted density functional theory (DFT) calculations on the ten aforementioned species. The DFT calculation enabled us to determine the vibrational frequency and assign normal modes, thereby facilitating the qualitative differentiation of amphetamines and its analogs. Furthermore, the SERS spectrum of the ten mentioned substances was analysed using the support vector machine learning algorithm, which yielded a discrimination accuracy of 98.0 %.

Controllable preparation of mesoporous spike gold nanocrystals for surface-enhanced Raman spectroscopy detection of micro/nanoplastics in water.

Microplastics and nanoplastics are emerging classes of environmental contaminants that pose significant threats to human health. In particular, small nanoplastics (<1 µm) have drawn considerable attention owing to their adverse effects on human health; for example, nanoplastics have been found in the placenta and blood. However, reliable detection techniques are lacking. In this study, we developed a fast detection method that combines membrane filtration technology and surface-enhanced Raman spectroscopy (SERS), which can simultaneously enrich and detect nanoplastics with sizes as small as 20 nm. First, we synthesized spiked gold nanocrystals (Au NCs), achieving a controlled preparation of thorns ranging from 25 nm to 200 nm and regulating the number of thorns. Subsequently, mesoporous spiked Au NCs were homogeneously deposited on a glass fiber filter membrane to form an Au film as a SERS sensor. The Au-film SERS sensor achieved in-situ enrichment and sensitive SERS detection of micro/nanoplastics in water. Additionally, it eliminated sample transfer and prevented the loss of small nanoplastics. Using the Au-film SERS sensor, we detected 20 nm to 10 µm standard polystyrene (PS) microspheres with a detection limit of 0.1 mg/L. We also realized the detection of 100 nm PS nanoplastics at the 0.1 mg/L level in tap water and rainwater. This sensor provides a potential tool for rapid and susceptible on-site detection of micro/nanoplastics, especially small-sized nanoplastics.

Controllable Preparation of Gold Nanocrystals with Different Porous Structures for SERS Sensing.

Porous Au nanocrystals (Au NCs) have been widely used in catalysis, sensing, and biomedicine due to their excellent localized surface plasma resonance effect and a large number of active sites exposed by three-dimensional internal channels. Here, we developed a ligand-induced one-step method for the controllable preparation of mesoporous, microporous, and hierarchical porous Au NCs with internal 3D connecting channels. At 25 °C, using glutathione (GTH) as both a ligand and reducing agent combined with the Au precursor to form GTH-Au(I), and under the action of the reducing agent ascorbic acid, the Au precursor is reduced in situ to form a dandelion-like microporous structure assembled by Au rods. When cetyltrimethylammonium bromide (C16TAB) and GTH are used as ligands, mesoporous Au NCs formed. When increasing the reaction temperature to 80 °C, hierarchical porous Au NCs with both microporous and mesoporous structures will be synthesized. We systematically explored the effect of reaction parameters on porous Au NCs and proposed possible reaction mechanisms. Furthermore, we compared the SERS-enhancing effect of Au NCs with three different pore structures. With hierarchical porous Au NCs as the SERS base, the detection limit for rhodamine 6G (R6G) reached 10-10 M.

Surface-enhanced Raman spectroscopy for detection of fentanyl and its analogs by using Ag-Au nanoparticles.

The problem of opioid abuse has become a global problem. Thus, creating an urgent need for highly sensitive detection of opioid substances. In this work, we developed a method for the controllable preparation of Ag@Au nanocrystals (Ag@Au NCs) for highly sensitive SERS detection of fentanyl and its analogs. By regulating the concentration of ligands on the surface of silver seed, we successfully prepared Ag@Au NCs with three different morphologies, including core-satellite, yolk shell and hollow structure. Firstly, we explored the SERS-enhancing effect of Ag@Au NCs with different morphology using rhodamine 6G as the molecule to be tested. The results show that the core-satellite Ag@Au NCs has the best SERS effect, and the lowest detection concentration for R6G reached to 10-10 M. Furthermore, we used the prepared core-satellite Ag@Au NCs to detect fentanyl and its five analogs, including carfentanyl, furanylfentanyl, thiofentanyl, 4-fluorobutyrfentanyl and N-4-piperidylacetanilide. Trace detection was achieved for the above six substances. For the environmental water samples spiked with fentanyl, the calculated recovery was 89.2% with an RSD value of 7.3%. Moreover, in order to realize the qualitative analysis of the characteristic peaks of different fentanyl analogs, we performed DFT calculations on the Raman spectra of the above-mentioned 6 substances. By analyzing the DFT calculation results, conventional Raman spectroscopy and SERS spectroscopy, we realized the distinction of six fentanyl analogs with similar structures.

Developmental toxicity induced by brodifacoum in zebrafish (Danio rerio) early life stages.

OBJECTIVES: The present study mainly focused on the assessment of developmental toxicity induced by exposure to brodifacoum (BDF) in zebrafish at early life stages. MATERIAL AND METHODS: Zebrafish embryos were exposed to 0.2, 0.4, and 0.8 mg/L of BDF from 6 to 96 hr post-fertilization (hpf), and the toxic effects of BDF on early embryonic development were investigated in terms of morphological changes, oxidative stress, and alterations in heart development-related genes. RESULTS: The experimental results showed that BDF significantly decreased the heart rate, survival rate, body length, and spontaneous movements of zebrafish embryos at 0.8 mg/L, and the morphological developmental abnormalities were also observed at 96 hpf. In addition, exposure to BDF significantly increased oxidative stress levels in zebrafish embryos by increasing the enzymatic activities of catalase (CAT), superoxide dismutase (SOD), and malondialdehyde (MDA) levels, and decreased glutathione (GSH) levels. Furthermore, BDF treatment-induced alterations in the expression levels of the heart development-related genes (gata4, sox9b, tbx2b, and nppa). CONCLUSION: Results from this study indicated that exposure to BDF could lead to marked growth inhibition and significantly alter the activities of antioxidant enzymes in zebrafish embryos. Moreover, BDF exposure exhibited severe cardiotoxicity and significantly disrupted heart development-related genes. The results indicated that BDF could induce developmental and cardiac toxicity in zebrafish embryos.

Comparison of intravitreal aflibercept and dexamethasone implant in the treatment of macular edema associated with diabetic retinopathy or retinal vein occlusion: a Meta-analysis and systematic review.

AIM: To compare the efficacy and safety of intravitreal aflibercept with dexamethasone implant in the treatment of macular edema (ME) associated with diabetic retinopathy (DR) or retinal vein occlusion (RVO). METHODS: A comprehensive search of studies comparing dexamethasone and aflibercept in patients with ME was conducted at PubMed, Embase, and Cochrane Central Register of Controlled Trials from the beginning of library to April 16, 2021. Extracting the data including best-corrected visual acuity (BCVA), central retinal thickness (CRT), number of injections and serious adverse events (SAEs) from the final qualified articles. RevMan 5.3 software was used for Meta-analysis of the included studies. RESULTS: Totally 7 studies with 369 eyes were included. The causes of ME in the final screening study included RVO and DR. Compared with the aflibercept treatment group, the BCVA of the dexamethasone implant treatment group showed no significant difference in the follow-up for 3mo [mean difference (MD): -0.05, 95% confidence interval (CI): -0.11, 0.02; P=0.17] and 12mo (MD: -0.01, 95%CI: -0.38, 0.37; P=0.98), but it was slightly worse than the aflibercept group at 6mo (MD: 0.12, 95%CI: 0.03, 0.21; P=0.008). In terms of CRT reduction, there was no significant difference between the two groups at 3mo (MD: -28.14, 95%CI: -79.95, 23.67; P=0.29), 6mo (MD: 27.67, 95%CI: -84.89, 140.24; P=0.63), and 12mo (MD: -59.00, 95%CI: -127.37, 9.37; P=0.09). However, dexamethasone implant had fewer injections, but more adverse events such as elevated intraocular pressure (IOP) and cataract. CONCLUSION: Intravitreal injection of aflibercept and dexamethasone implant can both effectively increase BCVA and reduce CRT. Compared with aflibercept, dexamethasone implant is not inferior in improving vision and reducing CRT in the initial treatment period (3mo) and long-term treatment period (12mo). Besides, it has fewer injections and more likely to cause elevated IOP and cataract.

Facile Synthesis of Porous Ag Crystals as SERS Sensor for Detection of Five Methamphetamine Analogs.

Porous noble metal nanomaterials have attracted extensive attention due to their high specific surface area and surface plasmon resonance effect. However, it is difficult to form porous structures due to the high mobility and low reduction potential of noble metal precursors. In this article, we developed a facile method for preparing porous Ag with a controllable structure at room temperature. Two kinds of Ag crystals with different porous structures were successfully prepared by using AgCl cubes as sacrificial templates. Through the galvanic replacement reaction of Zn and AgCl, Ag crystals with a sponge-like porous structure were successfully prepared. Additionally, using NaBH4 as the reducing agent, we prepared granular porous Ag cubes by optimizing the amount of reducing agent. Both the sponge-like and granular porous Ag cubes have clean and accessible surfaces. In addition, we used the prepared two porous Ag cubes as substrate materials for SERS detection of five kinds of methamphetamine analogs. The experimental results show that the enhancement effect of granular porous Ag is better than that of sponge-like porous Ag. Furthermore, we probed the hot spot distribution of granular porous Ag by Raman mapping. By using granular porous Ag as the substrate material, we have achieved trace detection of 5 kinds of methamphetamine analogs including Ephedrine, Amphetamine, N-Methyl-1-(benzofuran-5-yl)propan-2-amine (5-MAPB), N-Methyl-1-(4-methoxyphenyl)propan-2-amine (PMMA) and N-Methyl-1-(4-fluorophenyl)propan-2-amine (4-FMA). Furthermore, to achieve qualitative differentiation of analogs with similar structures we performed density functional theoretical (DFT) calculations on the Raman spectra of the above analogs. The DFT calculations provided the vibrational frequencies, Raman activities, and normal mode assignment for each analog, enabling the qualitative differentiation of the above analogs.

Aqueous angiopoietin-like levels correlate with optical coherence tomography angiography metrics in diabetic macular edema.

AIM: To quantitatively detect aqueous levels of angiopoietin-like (ANGPTL)3, ANGPTL4, and ANGPTL6 and investigate their correlation with optical coherence tomography angiography (OCTA) findings in patients with diabetic macular edema (DME). METHODS: This cross-sectional study included 23 patients (27 eyes) with type 2 diabetes and 16 control subjects (20 eyes). All patients underwent OCTA imaging and ultra-wide field fundus photography. Diabetic patients were categorized into two groups according to the presence or absence of diabetic retinopathy (DME group, 14 patients, 16 eyes); and non-diabetic retinopathy (NDR) group, 9 patients, 11 eyes, respectively. Aqueous levels of ANGPTL3, ANGPTL4, and ANGPTL6 were assessed using suspension array technology, and foveal-centered 3×3 mm2 OCTA scans were automatically graded to determine the central, inner, and full vessel density (CVD, IVD, FVD); central, inner, and full perfusion density (CPD, IPD, FPD), foveal avascular zone (FAZ) area, FAZ perimeter, and FAZ circularity index (FAZ-CI) on superficial capillary plexuses. Additionally, central subfield thickness (CST), cube volume (CV), and cube average thickness (CAT) were measured in a model of macular cube 512×128. RESULTS: Aqueous ANGPTL3 levels were not significantly different among the three groups (P>0.05). ANGPTL4 levels were significantly higher in the DME group than the control and NDR groups (P<0.0001 and P<0.001), while ANGPTL6 levels were significantly higher in the DME group than the control group (P<0.05). In the whole cohort, the aqueous ANGPTL3 levels correlated negatively with the IVD, FVD, IPD, and FPD, and positively with the CV and CAT. The aqueous ANGPTL4 levels correlated negatively with the CVD, IVD, FVD, CPD, IPD, and FPD, and positively with the FAZ perimeter, CST, CV, and CAT. The aqueous ANGPTL6 levels correlated negatively with the IVD, FVD, IPD, FPD, FAZ-CI and positively with CST, CV, CAT. CONCLUSION: ANGPTL4 and ANGPTL6 may be associated with vascular leakage in DME and may represent good targets for DME therapy. In addition, OCTA metrics may be useful for evaluating macular ischemia in DME.

[Development of Magnetic Anchoring Lung Nodule Positioning Device].

The magnetic anchoring lung nodule positioning device is composed of a target magnet, an anchor magnet, a coaxial puncture needle and a puncture navigation template, through these, a new type of accurate positioning technology for small pulmonary nodules is derived. The device inserts the target magnet into the both sides nearby the lung nodule under the guidance of CT. Helped by the mutual attraction of the two target magnets, they can be fixed in the lung tissue, avoiding the movement in the lung, and accurately positioning the target lung nodule before surgery. In thoracoscopic surgery, the anchor magnet and the target magnet attract each other to achieve the purpose of positioning the target nodule. The device uses the characteristics of non-contact suction of magnetic materials biomedical engineering technology, eliminating the previous procedure of direct interaction with the positioning marks, finally achieves the target of precise positioning of lung nodules and rapid surgical removal.

Controllable preparation of sea urchin-like Au NPs as a SERS substrate for highly sensitive detection of the toxic atropine.

Branched Au nanoparticles (Au NPs) can significantly enhance the Raman signal of trace chemical substances, and have attracted the interest of researchers. However, there are still challenges to accurately prepare the morphology of branched Au NPs. In this work, we have successfully prepared sea urchin-like Au NPs and Au nanowires by using the seed-mediate growth method, with cetyltrimethylammonium bromide (CTAB) and glutathione as ligands, and ascorbic acid as a reducing agent. Using Au NPs with a tetrahexahedron (THH) morphology as seeds, and by simply changing the concentration of glutathione, we explored the growth process of sea urchin-like Au and Au nanowires. At low concentrations of glutathione, Au NPs will preferentially grow along the edges and corners of the THH Au seed, forming a core/satellite structure. As the concentration of glutathione increases, Au NPs will grow along the direction of glutathione, forming sea urchin-like Au NPs. To further increase the concentration of glutathione, we will prepare Au nanowires. In addition, we use the prepared Au NPs as a substrate material for surface-enhanced Raman (SERS) high-sensitivity detection. By using 4-aminothiophenol (4-ATP) as the test molecule, we evaluated the SERS effect of the prepared Au NPs with different morphologies. The results showed that sea urchin-like Au NPs have the best enhancement effect. The lowest concentrations of Rhodamine 6G and 4-ATP were 10-10 M and 10-12 M, respectively, using sea urchin Au NPs as the base material. Furthermore, we conducted a highly sensitive SERS detection of the poison atropine monohydrate, and the lowest detected concentration was 10-10 M.

Comparison of the clinical efficacy of AcrySof® IQ and TECNIS® toric intraocular lenses: A real-world study.

Corneal astigmatism significantly compromises uncorrected visual acuity (UCVA) after phacoemulsification with implantation of traditional spherical or non-spherical monofocal intraocular lens (IOL). Toric IOL provides an effective way to gain favorable postoperative UCVA for the patients with cataracts with corneal astigmatism. There are numerous types of toric IOLs; however AcrySof® IQ toric IOL (Alcon Laboratories, Inc.) and TECNIS® toric IOL (Johnson & Johnson Vision; Johnson & Johnson) are most frequently used in our clinical practice. The purpose of the current study was to compare the clinical efficacy of AcrySof IQ with TECNIS toric IOL implantation, and to provide a clinical basis on selecting an appropriate toric IOL before cataract surgery for patients with corneal astigmatism. A total of 30 patients with cataract (44 eyes) with corneal astigmatism [0.82-7.27 diopters (D)], who have undergone phacoemulsification with toric IOL implantation between October 2012 and December 2017, were included in the current retrospective cohort study. Patients were divided into two groups: One group (26 eyes) received the AcrySof IQ toric IOL (AcrySof group) and the other group (18 eyes) received the TECNIS toric IOL (Tecnis group). The indexes of curative effect, such as uncorrected and corrected distance visual acuity (UDVA and CDVA, respectively), refractive outcomes, contrast sensitivity (CS), IOL rotation, and satisfaction, were evaluated. Both toric IOLs significantly improved UDVA and CDVA. Postoperative mean residual astigmatism was similar in the AcrySof group and in the Tecnis group (0.75±0.50 and 0.78±0.90 D; P=0.896). There was no statistically significant between postoperative CS in the AcrySof and Tecnis groups. Rotations of >10˚ were considered to be significant and were identified in three eyes. The mean IOL rotation showed no statistically significant difference (AcrySof group, 0.24±5.54˚; Tecnis group, -0.19±6.28˚; P=0.416). The mean patient satisfaction score was 8.46±1.21 in the AcrySof group and 8.78±1.44 in the Tecnis group (P=0.260). The results of the current study indicated that patients with cataracts with corneal astigmatism undergoing phacoemulsification with AcrySof IQ and TECNIS toric IOL implantation achieved similar clinical efficacy in term of visual outcomes, refraction correction, CS, rotational stability and satisfaction.

Acetylcholinesterase inhibition ameliorates retinal neovascularization and glial activation in oxygen-induced retinopathy.

AIM: To investigate whether inhibition of acetylcholinesterase (AChE) by donepezil ameliorate aberrant retinal neovascularization (RNV) and abnormal glial activation in oxygen-induced retinopathy (OIR). METHODS: A mouse model of RNV was induced in postnatal day 7 (P7) mice by exposure to 75% oxygen. Donepezil was administrated to P12 mice by intraperitoneal injection. Expression and localization of AChE in mouse retinas were determined by immunofluorescence. RNV was evaluated by paraffin sectioning and hematoxylin and eosin (HE) staining. Activation of retinal Müller glial cells were examined by immunoblot of glial fibrillary acidic protein (GFAP). rMC-1, a retinal Müller cell line, was used for in vitro study. Expression of hypoxia-induced factor 1α (HIF-1α) and vascular endothelial growth factor (VEGF) were determined by Western-blot analysis, enzyme-linked immunosorbent assay (ELISA) or immunostaining. RESULTS: Aberrant RNV and glial activation was observed after OIR. Of note, retinal AChE was mainly expressed by retinal Müller glial cells and markedly increased in OIR mice. Systemic administration of donepezil significantly reduced RNV and abnormal glial activation in mice with OIR. Moreover, ischemia-induced HIF-1α accumulation and VEGF upregulation in OIR mouse retinas and cultured rMC-1 were significantly inhibited by donepezil intervention. CONCLUSION: AchE is implicated in RNV with OIR. Inhibition of AChE by donepeizl is likely to be a potential therapeutic approach for retinal neovascular diseases.

Effects of vacancy defects on the mechanical properties in neutron irradiated Czochralski silicon.

We have investigated the mechanical properties of neutron irradiated Czochralski (NICZ) silicon using nanoindentations combined with micro-Raman spectroscopy. It is found that NICZ silicon shows higher hardness (∼13% higher) than non-irradiated silicon, with a slightly lower Young's modulus. When the samples were subjected to isochronal anneals in the temperature range of 250 °C-650 °C, the hardness of NICZ silicon gradually decreases as the temperature increases and it is finally comparable to that of the non-irradiated silicon. The vacancies and vacancy-oxygen defects induced by neutron irradiation in NICZ silicon annihilate or transform into more complex defects during the annealing processes. It suggests that the vacancy defects play a role in the evolution of hardness, which promote phase transition from the Si-I phase to the stiffer Si-II phase in NICZ silicon during indentation. In addition, the irradiation induced vacancy defects could lead to the lower Young's modulus.

SNAI1 interacts with HDAC1 to control TGF­ß2­induced epithelial­mesenchymal transition in human lens epithelial cells.

The opacity of the lens capsule after cataract surgery is caused by epithelial­to­mesenchymal transition (EMT) of lens epithelial cells. Snail family transcriptional repressor 1 (SNAI1) is a transcriptional repressor that recruits multiple chromatin enzymes including lysine­specific histone demethylase 1A, histone deacetylase (HDAC) 1/2, polycomb repressive complex 2, euchromatic histone lysine methyltransferase 2 and suppressor of variegation 3­9 homolog 1 to the E­cadherin promoter, thereby suppressing E­cadherin expression. However, the functional relationship between SNAI1 and HDAC in the induction of EMT in human lens epithelial cells (HLECs) is still unclear. Therefore, the objective of the present study was to explore the possible functional relationship between SNAI1 and HDAC1 in the induction of EMT in HLECs. In the present study, SNAI1 was found to be increased in HLECs during transforming growth factor­ß2 (TGF­ß2)­induced EMT. Knockdown of SNAI1 by siRNA reversed TGF­ß2­induced downregulation of E­cadherin and upregulation of α­Smooth Muscle Actin. Furthermore, SNAI1 was found to be associated with HDAC1 in the E­cadherin promoter in TGF­ß2­treated HLECs. Inhibition of HDAC by trichostatin A and suberoylanilide hydroxamic acid could prevent TGF­ß2­induced EMT in HLECs. Collectively, SNAI1 interacted with HDAC1 to repress E­cadherin in the TGF­ß2­induced EMT in HLECs, suggesting that HDAC inhibitors may have potential therapeutic value for the prevention of EMT in HLECs.

Aligner mediated cleavage of nucleic acids for site-specific detection of single base mismatch.

Single base mismatch can always connect with various gene-related diseases, whose determination has aroused widespread interest. So far, various methods have been developed to determine the common base mismatch. However most of them are complex, time-consuming. Herein, we report a novel method, which only need one conventional endonuclease (NEase) and achieve site-specific cleavage in a programmable way, to detect single base mismatch, termed aligner-mediated cleavage-based single base mismatch discrimination (AMCMD). The DNA aligner (DA) is in a stem-loop structure, consistent with an incomplete recognition site of NEase on its stem and a 5'-side arm complementary to the target sequence (TS). Once TS contains matched base and hybridizes with DA, the complete recognition site of NEase is formed, and the TS will be cleavaged with fast speed, while converse is not. Based on it, the method can clearly distinguish mismatched and complementary bases. Without sample pre-processing, we were able to obtain and verify all the test result in about 30 min through the polyacrylamide gel electrophoresis analysis. This endows the proposed method with a simpler advantage. Then we combined AMCMD and EXPAR to create a new method for single base mismatch discrimination, the short sequence obtained by AMCMD as a target to trigger EXPAR, with a detection limit at 1pM level. Another process with human serum underlines that AMCMD is compatible with the complex biological sample, thus it has the potentials for practical applications.

One-pot synthesis of hollow hydrangea Au nanoparticles as a dual catalyst with SERS activity for in situ monitoring of a reduction reaction.

The controlled synthesis of metallic nanomaterials has attracted the interest of many researchers due to their shape-dependent physical and chemical properties. However, most of the synthesized nanocrystals cannot be combined with spectroscopy to measure the reaction kinetics, thus limiting their use in monitoring the catalytic reaction process to elucidate its mechanism. As a powerful analytical tool, surface-enhanced Raman spectroscopy (SERS) can be used to achieve in situ monitoring of catalytic reactions by developing bifunctional metal nanocrystals with both SERS and catalytic activities. Herein, we have developed a simple one-pot synthesis method for the large-scale and size-controllable preparation of highly rough hydrangea Au hollow nanoparticles. The growth mechanism of flower-like Au hollow nanostructures was also discussed. The hollow nanostructure with a 3D hierarchical flower shell combines the advantages of hollow nanostructure and hierarchical nanostructure, which possess high SERS activity and good catalytic activity simultaneously. Furthermore, the hydrangea Au hollow crystals were used as a bifunctional nanocatalyst for in situ monitoring of the reduction reaction of 4-nitrothiophenol to the 4-aminothiophenol.

Interspecies Interactions in Relation to Root Distribution Across the Rooting Profile in Wheat-Maize Intercropping Under Different Plant Densities.

In wheat-maize intercropping systems, the maize is often disadvantageous over the wheat during the co-growth period. It is unknown whether the impaired growth of maize can be recovered through the enhancement of the belowground interspecies interactions. In this study, we (i) determined the mechanism of the belowground interaction in relation to root growth and distribution under different maize plant densities, and (ii) quantified the "recovery effect" of maize after wheat harvest. The three-year (2014-2016) field experiment was conducted at the Oasis Agriculture Research Station of Gansu Agricultural University, Wuwei, Northwest China. Root weight density (RWD), root length density (RLD), and root surface area density (RSAD), were measured in single-cropped maize (M), single-cropped wheat (W), and three intercropping systems (i) wheat-maize intercropping with no root barrier (i.e., complete belowground interaction, IC), (ii) nylon mesh root barrier (partial belowground interaction, IC-PRI), and (iii) plastic sheet root barrier (no belowground interaction, IC-NRI). The intercropped maize was planted at low (45,000 plants ha-1) and high (52,000 plants ha-1) densities. During the wheat/maize co-growth period, the IC treatment increased the RWD, RLD, and RSAD of the intercropped wheat in the 20-100 cm soil depth compared to the IC-PRI and IC-NRI systems; intercropped maize had 53% lower RWD, 81% lower RLD, and 70% lower RSAD than single-cropped maize. After wheat harvest, the intercropped maize recovered the growth with the increase of RWD by 40%, RLD by 44% and RSAD by 11%, compared to the single-cropped maize. Comparisons among the three intercropping systems revealed that the "recovery effect" of the intercropped maize was attributable to complete belowground interspecies interaction by 143%, the compensational effect due to root overlap by 35%, and the compensational effect due to water and nutrient exchange (CWN) by 80%. The higher maize plant density provided a greater recovery effect due to increased RWD and RLD. Higher maize plant density stimulated greater belowground interspecies interaction that promoted root growth and development, strengthened the recovery effect, and increased crop productivity.