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This paper focuses on the study of ground states and nontrivial solutions for the following Hamiltonian elliptic system: { − Δ u + V ( x ) u = f 1 ( x , v ) , x ∈ R 2 , − Δ v + V ( x ) v = f 2 ( x , u ) , x ∈ R 2 , where V ∈ C ( R 2 , ( 0 , ∞ ) ) and f 1 , f 2 : R 2 × R → R have critical exponential growth. The strongly indefinite features together with the critical exponent bring some new difficulties in our analysis. In this paper, we develop a direct approach and use an approaching argument to seek Cerami sequences for the energy functional and estimate the minimax levels of such sequences. In particular, under some general assumptions imposed on the nonlinearity f i , we obtain the existence of ground states and nontrivial solutions for the above system as well as the following system in bounded domain, { − Δ u = f 1 ( v ) , x ∈ Ω , − Δ v = f 2 ( u ) , x ∈ Ω , u = 0 , v = 0 , x ∈ ∂ Ω . Our results improve and extend the related results of de Figueiredo-do O-Ruf (2004) [20] ; (2011) [21] , of Lam-Lu (2014) [30] , and of de Figueiredo-do O-Zhang (2020) [22] .

In the present paper, we study the following planar Choquard equation: { − Δ u + V ( x ) u = ( I α ⁎ F ( u ) ) f ( u ) , x ∈ R 2 , u ∈ H 1 ( R 2 ) , where V ( x ) is an 1-periodic function, I α : R 2 → R is the Riesz potential and f ( t ) behaves like ± e β t 2 as t → ± ∞ . A direct approach is developed in this paper to deal with the problems with both critical exponential growth and strongly indefinite features when 0 lies in a gap of the spectrum of the operator − △ + V . In particular, we find nontrivial solutions for the above equation with critical exponential growth, and establish the existence of ground states and geometrically distinct solutions for the equation when the nonlinearity has subcritical exponential growth. Our results complement and generalize the known ones in the literature concerning the positive potential V to the general sign-changing case, such as, the results of de Figueiredo-Miyagaki-Ruf (1995) [16] , of Alves-Cassani-Tarsi-Yang (2016) [4] , of Ackermann (2004) [1] , and of Alves-Germano (2018) [5] .

In this paper, we study the following non-autonomous Choquard-Pekar equation: { − Δ u + V ( x ) u = ( W ⁎ F ( u ) ) f ( u ) , x ∈ R N ( N ≥ 2 ) , u ∈ H 1 ( R N ) , where the potential V ( x ) is 1-periodic and 0 lies in a gap of the spectrum of the Schrodinger operator − Δ + V . Under some general assumptions on the potential W and the nonlinearity f, we show the existence of ground state solutions. We also construct infinitely many geometrically distinct solutions by using the variational method and deformation arguments.

Brain-derived neurotrophic factor (BDNF) is involved in pathophysiological mechanisms in neuropsychiatric diseases, including depression, anxiety, and schizophrenia (SZ), as well as neurodegenerative diseases like Parkinson's disease (PD) and Alzheimer's disease (AD). An imbalance or insufficient pro-brain-derived neurotrophic factor (proBDNF) transformation into mature BDNF (mBDNF) is potentially critical to the disease pathogenesis by impairing neuronal plasticity as suggested by results from many studies. Thus, promoting proBDNF transformation into mBDNF is therefore hypothesized as beneficial for the treatment of neuropsychiatric and neurodegenerative diseases. ProBDNF is proteolytically cleaved into the mBDNF by intracellular furin/proprotein convertases and extracellular proteases (plasmin/matrix metallopeptidases). This article reviews the mechanisms of the conversion of proBDNF to mBDNF and the research status of intracellular/extracellular proteolytic proteases for neuropsychiatric and neurodegenerative disorders.

This paper addresses the formation problem for multiple mobile robots with velocity mismatch and system constraints by a distributed model predictive control (DMPC) strategy and a modified virtual structure method. Firstly, a desired virtual structure is employed to generate a set of reference paths for the formation robots. By including approaching angle and path parameter synchronization constraints into cost function, a Nash-based DMPC strategy is presented, where a velocity integral controller is developed to solve the velocity mismatch. Further, consider state and input constraints, the distributed optimization problem is rewritten as a constrained quadratic programming (QP) problem. A PDNN is used to obtain the optimal control input increments, and the stability of the proposed algorithm is analyzed. Moreover, the dynamic formation control is achieved by a modified virtual structure method, and simulation examples are given to verified the effectiveness of the proposed strategies.

This paper is concerned with existence of multiple semiclassical states for a class of Choquard equation. Under the classic Berestycki–Lions type assumptions assumed on the nonlinearity, we obtain multiplicity of semiclassical solutions for the equation by using a method of penalization argument. We study further the concentration phenomena of such solutions and show that they converge to the least energy solutions of the associated limit problem as the parameter e goes to 0.

In this paper we consider the following Klein–Gorden–Maxwell system − Δ u + V 0 u − ( 2 w + ϕ ) ϕ u = λ | u | p − 2 u + | u | 4 u , x ∈ R 3 , Δ ϕ = ( w + ϕ ) u 2 , x ∈ R 3 , where λ , w and V 0 are positive real constants. By employing some analytical skills and using the variational method, we prove some results about the existence of ground state solutions for the system under a general condition imposed on V 0 . Our results improve and extend some related ones in the literature.

Thallium (Tl) is a non-essential, highly toxic element having Tl(I) and Tl(III) two redox states. Tl(III) is more toxic to organisms than Tl(I) but is less of attention. The objective of this study was to investigate the reason of Tl(III) instability in the presence of plant. The content of Tl(III) was rapidly reduced from 100% to 16.1% in Tl solution cultivating rice seedlings while content of Tl(I) was increased from 0 to 83.8% within 8 h. High performance liquid chromatography (HPLC) analysis showed that organic acids exudates in rice roots caused the pH decline in rhizosphere, but only oxalate was the specific organic acid in root exudates under Tl stress. The anion channel inhibitor, nifiumic acid (NIF), could efficiently inhibit the oxalate exudation but had no effect on oxalate content in root cytosol compared with Tl treatment. The exogenous oxalate, malate and citrate significantly contributed the reduction of Tl(III) to Tl(I). It was concluded that the contact of Tl(III) with organic acids in plant cells or in root exudates promoted the instability of Tl(III) with plants. Meanwhile, the presence of DTPA could effectively restrain the conversion of Tl(III) to Tl(I). This study provided better understanding of the basic biochemical mechanism for the reduction of Tl(III) in contact with plants. It will contribute to controlling relevant factors to stabilize Tl(III) for further toxic assessment on organism and to studying Tl(III) behavior in ecological system.

In the present work, we proposed a novel naked-eye and turn-on fluorescence sensor based on the 5,10,15,20-(4-sulphonatophenyl) porphyrin (TPPS4)-Hg2+ system with short assay time and high sensitivity to detect glutathione (GSH) in real samples. The TPPS4 was the first time to detect GSH because of its high fluorescence quantum yield. The initial fluorescence from TPPS4 was quenched by Hg2+ with an electron transfer process. However, when put a certain concentration of GSH into this system, the fluorescence sensor was turned to the “on” state, which was related to a competitive affinity of Hg2+ to GSH and the N atoms of porphyrin ring. Under the optimal conditions, the naked-eye detection limit was 0.43 nM and the limit of detection (LOD) was arrived to 16 fM (S/N = 3) for GSH. The linear regions are obtained by two ranges varying from 0 to 28.5 μM and from 38.15 to 61.87 μM. Furthermore, it was confirmed that the TPPS4-Hg2+ fluorescence probe has excellent selectivity, high sensitivity and quick fluorescence response for GSH.

This paper is concerned with existence of bound states for a coupled gradient system of nonautonomous Schrodinger equations which arises from studies of nonlinear optics and Bose–Einstein condensates. By using variational methods that are constrained to a Nehari–Pohozaev manifold, we obtain existence of nonnegative and positive bound states solutions. In Particular, we show non-existence result for a minimizing problem.

We consider a parametric ( p , q ) -equations with sign-changing reaction and Robin boundary condition. We show that for all values of the parameter λ bigger than a certain value which we determine precisely, the problem has at least three nontrivial solutions all with sign information and ordered. For the particular case of ( p , 2 ) -equations we produce a second nodal solution, for a total of four nontrivial solutions. Under symmetry conditions, we show the existence of infinitely many nodal solutions. The same results are also valid for the Dirichlet problem.

Signal amplification through the grafting of polymers has attracted increasing attention in biodetection at ultralow concentrations. Herein, an ultrasensitive peptide nucleic acid (PNA)-based electrochemical DNA biosensor is reported by using the coenzyme-mediated electro-grafting of polymers as a novel amplification method. For the capture of DNA target, PNA is used as the probe. After hybridization, reversible addition-fragmentation chain-transfer (RAFT) agents are site-specifically tethered to the deoxyribose phosphate backbone of the captured DNA targets via the carboxylate-Zr(IV)-phosphate cross-linking chemistry. Subsequently, electro-grafting of polymers through the nicotinamide adenine dinucleotide (NAD+) coenzyme-mediated electro-RAFT (NAD+-eRAFT) polymerization of ferrocenylmethyl methacrylate (FcMMA) recruits numerous ferrocene redox tags for voltammetric measurement. As the electro-grafting of polymers involves simply i) the tethering of RAFT agents and ii) the NAD+-eRAFT polymerization, it is highly efficient, easy to use, and low-cost. Under optimal conditions, the voltammetric signal correlates linearly with the logarithm of DNA concentration over the range from 0.1 fM to 0.1 nM (R2 = 0.996), with a detection limit of 0.067 fM. The PNA-based electrochemical DNA biosensor can also differentiate even single base mismatch and is applicable to DNA detection in the presence of complex serum matrices, thus showing great promise in the sequence-specific detection of DNA targets at ultralow concentrations.

This paper focuses on the study of ground states and multiple solutions for the following non-autonomous Choquard-Pekar equation: { − Δ u + V ( x ) u = ( W ⁎ F ( x , u ) ) f ( x , u ) , x ∈ R N ( N ≥ 2 ) , u ∈ H 1 ( R N ) , where V ∈ C ( R N , R ) . We consider first the case V changes sign which turns the problem into a indefinite case, and obtain the existence of nontrivial solution and infinitely many distinct pairs of solutions under a local super-linear condition assumed on the nonlinearity. For the case V is 1-periodic and positive, ground state solution and infinitely many solutions are established further by using the generalized Nehari manifold method. We finally give some non-existence criteria via a generalized Pohožaev identity established for the general potentials V and W.

Graphitic carbon nitride quantum dots (g-CNQDs) are rarely used in the field of electrochemiluminescence. In this paper, g-CNQDs have a strong and stable electrochemiluminescence (ECL) signal generated in the presence of co-reactant K2S2O8. The ECL signal of g-CNQDs was quenched by the mechanism of resonance energy transfer (RET) between donor g-CNQDs and receptor riboflavin (RF) that is proved by UV-vis absorption spectroscopy, electrochemiluminescence and fluorescence emission spectroscopy analysis technology. Therefore, we achieved detection of the riboflavin content in the drug tablets of vitamin B2 using ECL and FL. The determination results of ECL showed that the riboflavin content of the drug vitamin B2 (VB2) tablets was consistent with the fluorescence (FL) analysis, with wider linear range of 0.02-11 μM and lower minimum detection limit of 0.63 nM (S/N = 3) than FL. Hence, the riboflavin content in human serum was further detected using ECL. The relative standard deviation is less than 6.5%, with an acceptable recovery of 95.33%-104.22%, which means that this sensor has potential applications in the actual sample analysis. As a new ECL luminary, g-CNQDs have opened a new field for the development and application of ECL sensor.

The design and synthesis of highly active hydrogen evolution reaction (HER) catalyst with strong stability is highly desirable and challenging. In this work, we followed simple two-step strategy to grow Nickel–Cobalt phosphide nanowires (NiCoP NWs) directly on the Ni foam (NF) by hydrothermal method. Catalytic current density of 10 mA cm −2 at an overpotential of 118 mV has been obtained. Prepared material exhibited long-term stability and nearly 100% Faradaic efficiency in 0.5 M H 2 SO 4 for HER. Ni and Co composite materials with amorphous structure are considered as better catalysts by exhibiting the higher activity. The results in this paper might promote further development of the advanced catalysts for special electrochemical properties and other devices.

In this study, graphene grafted Ag 3 PO 4 @AgBr (GO-Ag 3 PO 4 @AgBr) composite with enhanced photocatalytic performance was synthesized via in situ fabrication method. The synthesized composite was characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS) and X-ray photoelectron spectroscopy (XPS). The GO-Ag 3 PO 4 @AgBr composite was exhibited higher activity than Ag 3 PO 4 @AgBr and bare Ag 3 PO 4 . The material characterization and the detailed study of the various parameters which affect the photocatalytic reaction, revealed that the enhanced catalytic activity is related to the surface electric property of the synthesized catalyst. The investigation of the energy band structure further considered as a reason for the enhancement of the multi-electron reaction. Furthermore, the effect of illuminated light on the catalytic performance was also investigated. The results indicated that simulated sunlight significantly affects the catalytic activity compared with visible light. In addition, the photocatalytic experimental conditions were tested, and sonication of the dye/catalyst reaction system for 10 min was selected to be the optimum condition to establish absorption – desorption equilibrium. This work could supply a new way to use natural sunlight to facilitate the practical application of photocatalysts in environment issues.

Being closely associated with a variety of physiological and pathological processes, matrix metalloproteinases (MMPs) are useful as potential targets for drug therapy and informative markers for disease diagnosis. On the basis of the electrochemically induced grafting of ferrocenyl polymers and the proteolytic cleavage of recognition peptide, a novel electrochemical sensor is presented in this work for the highly specific interrogation of MMP activities at ultralow levels. The recognition peptide, to be immobilized via the N-terminus, is free of carboxyl group. The presence of the target MMP would cleave the end-tethered recognition peptide, generating a free carboxyl group at the C-terminus of the rest fragment. To be used as the reversible addition−fragmentation chain-transfer (RAFT) agent, the dithiobenzoate, 4-cyano-4-(phenylcarbonothioylthio)pentanoic acid (CPAD), can therefore be tethered via the carboxylate-Zr(IV)-carboxylate chemistry. Subsequently, the grafting of ferrocenyl polymers through electrochemically induced RAFT (eRAFT) polymerization of ferrocenylmethyl methacrylate (FcMMA) would recruit a large quantity of Fc redox reporters on electrode surface. With benefits from the excellent specificity of the enzyme-substrate recognition, the presented cleavage-based sensor is highly selective. Under optimal conditions, the detection limit in the presence of MMP-2 as the model target can be as low as 0.27 pg mL−1, with a linear range from 1 pg mL−1 to 1 ng mL−1. Furthermore, its applicability in the interrogation of MMP activity in complex serum samples and the screening of MMP inhibitors is satisfactory. The presented cleavage-based electrochemical MMP sensor is easy to fabricate and low-cost, thus showing great promise in drug discovery and disease diagnosis.

Scanning electrochemical microscopy(SECM) has made great progress in recent years with respect to both technology and applications. This manuscript is an expansion of the review published in Analytica chimica acta in the year of 2007 by our group. The review briefly presents the principle and instrumentation of SECM. Then we focus on the application of SECM in several areas such as charge transfer, solar cells, imaging, bioanalysis in recent years. SECM can capture real time (electro)chemical information at a micro interface which helps us to explore the microscopic world. SECM is also employed to investigate the complicated electron transfer system and biosamples. Last seven years literature infers SECM is a comprehensive characterization tool when it is combined with other techniques.

Chronic stress is an important cause for depression. However, not everyone who is exposed to chronic stress will develop depression. Our previous studies demonstrated that early adversity can cause lasting changes in adolescent rhesus monkeys, but depressive symptoms have not been observed. Compared to adults, it is still unknown that whether adolescent rhesus monkeys experiencing early adversity are more likely to develop depressive symptoms. In this study, we investigated the long term relationship between early adversity, chronic stress and adolescent depression for the first time. Eight male rhesus monkeys were reared in maternal separation (MS) or mother-reared (MR) conditions. All of them went through unpredictable chronic stress for two months at their age four. The stressors included space restriction, intimidation, long illumination and fasting. Behavioral and physiological data were collected during the experiment. The results showed that, compared with the MR group, the locomotor activity of MS group was significantly decreased after one month of chronic stress while huddling up and stereotypical behaviors were significantly increased. Moreover, this trend continued and even worsened at the second month. Significantly higher hair cortisol levels and lower body weight were observed in MS group after two months of stress. These results indicate that early adversity is one of the environmental factors which can increase the susceptibility of depression when experiencing chronic stress in the later life. This will further clarify the important roles of early environmental factors in the development of adolescent depression and children rearing conditions should receive more attention.

In this paper, an easy carbon radicals reaction procedure is put forward to functionalized graphene-supported Pt–Pd bimetallic nanoparticles (NPs). To begin with, graphene was functionalized with carboxylic sodium electro-catalyst through method of π–π interaction, which could provide more binding sites for Pt–Pd NPs. Then a fast method of in-situ electrochemical reduction was developed to synthesize highly dispersed Pt–Pd NPs on functionalized graphene. The prepared nanocomposite was characterized by Raman spectroscopy, thermogravimetric analysis (TGA), Fourier transformed infrared spectrometry (FT-IR), scanning electron microscopy (SEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), and electrochemical technique. The obtained nanocomposite shows much high catalytic activity and long-term stability towards methanol oxidation than that of Pt or Pd black. It was suggesting the synergetic effects of bimetallic NPs. Moreover, it demonstrates that the incorporation of the carbon radical reaction with electrochemical reduction method is a novel approach to functionalize graphene. Our study may provide a new insight into electro-oxidation of methanol on bimetallic material.

This paper is concerned with the following Kirchhoff type equation: { - ( a + b ? ? | ? v | 2 ) Δ v = f ( x , v ) in ? , v = 0 on ? ? . Assuming that the primitive of f is asymptotically 4-linear as | v | ? ∞ , a homeomorphism between the Nehari manifold and a subset of unit sphere is constructed based on some observations and new techniques. Inspired by recent work of Szulkin and Weth (2010), ground state solutions for the equation above are obtained, as well as infinitely many pairs of nontrivial solutions for case f ( x , v ) ?is odd with respect to v .

Checkpoint kinase 1 (Chk1) is a serine/threonine kinase that plays a key role in the response to DNA-mediated cell injury. In this paper, the quantitative structure–activity relationship (QSAR) models were constructed to predict the activity of pyrazolo[1,5-a]pyrimidine derivatives of Checkpoint kinase 1 (Chk1) by using SVM and PSO-SVM methods. The root-mean-square errors ( RMSE ) of the training set and the test set for the PSO-SVM model were 0.0886 and 0.1803, respectively. For the SVM model, the values were 0.2185 and 0.4023, respectively. The results showed that the performance of the PSO-SVM model was better than the corresponding SVM model. Thus, it can be inferred that the PSO-SVM analysis will be a promising method and be spread to apply in the QSAR studies.

In this paper, we focus our attention on following Schrodinger–Poisson system: − e 2 Δ u + V ( x ) u + λ ψ u = | u | p − 2 u , x ∈ R 3 , − e 2 Δ ψ = u 2 , u ∈ H 1 ( R 3 ) . where 4 p 6 and e , λ > 0 are small positive parameters. Under a local condition imposed on the potential V , we study above system and obtain an infinite sequence of localized sign-changing solutions by applying the symmetric mountain pass theorem. Precisely, these solutions are constructed as higher topological type critical points of the energy functional and concentrated at a local minimum set of the potential V . Our method follows the same spirit of Chen and Wang’s method (Chen and Wang, 2017) which does not need any non-degeneracy condition of the limiting equations, but we cannot use it directly due to the presence of nonlocal term ψ ( x ) = 1 4 π ∫ R 3 u 2 ( y ) | x − y | d y . We employ some new analytical skills to overcome the obstacles caused by the nonlocal term, our results improve and extend some related ones in the literature.

In this paper, we study following Choquard equation with lower critical exponent: − Δ u + V ( x ) u = ( I α ∗ | u | α N + 1 ) | u | α N − 1 u + f ( x , u ) , x ∈ R N , u ∈ H 1 ( R N ) , where N ≥ 1 , I α is the Riesz potential, and V : R N → R allows to be sign-changing. Under some mild assumptions imposed on the nonlinearity f , we prove that above equation has a ground state solution for the periodic case and asymptotically periodic case, respectively. The characterization of the ground states is also investigated by a direct approach that are constrained to the Nehari manifold. Moreover, we show a non-existence result for the equation via a generalized Pohožaev identity established for the non-autonomous nonlinearity f . The results extend and improve some recent ones in the literature.

In this paper, we consider the following Kirchhoff problem: − ( 1 + b ∫ R 3 | ∇ u | 2 d x ) Δ u + V ( x ) u = f ( u ) , x ∈ R 3 , u ∈ H 1 ( R 3 ) , where b is a positive constant. Assume that f ( u ) is an odd function of u . Under some appropriate assumptions on V but without radial symmetry or compactness hypotheses, we establish the existence of infinitely many solutions to the above problem by using an approximation method employed by Sato and Shibata (2018) and some new arguments.

Diurnal animals are a better model for seasonal affective disorder (SAD) than nocturnal ones. Previous work with diurnal rodents demonstrated that short photoperiod conditions brought about depression-like behavior. However, rodents are at a large phylogenetic distance from humans. In contrast, nonhuman primates are closely similar to humans, making them an excellent candidate for SAD model. This study made the first attempt to develop SAD in rhesus macaque (Macaca mulatta) and it was found that short photoperiod conditions could lead monkeys to display depressive-like huddling behavior, less spontaneous locomotion, as well as less reactive locomotion. In addition to these depression-related behavioral changes, the physiological abnormalities that occur in patients with SAD, such as weight loss, anhedonia and hypercortisolism, were also observed in those SAD monkeys. Moreover, antidepressant treatment could reverse all of the depression-related symptoms, including depressive-like huddling behavior, less spontaneous locomotion, less reactive locomotion, weight loss, anhedonia and hypercortisolism. For the first time, this study observed the SAD symptoms in rhesus macaque, which would provide an important platform for the understanding of the etiology of SAD as well as developing novel therapeutic interventions in the future.

In this work, Fe-doped Co 3 O 4 nanofilms were fabricated by electrodeposition on FTO glass substrates for the first time. The structures of the as-prepared nanofilms were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Characterization results demonstrate that Fe was doped homogeneously in the nanofilms. As the different concentration ratios of Fe 2+ /Co 2+ were explored, nanofilm with the ratio of 1:5 exhibits the optimal performance in electrochemical properties assessments. It is considered that the difference in the catalytic activities for the ORR of the samples may be due to the fact that the joining of iron changed the catalyst surface's electric state and enhanced the acidity of cobalt centers, on the other hand, the doping process probably modified the absorption property of the nanofilms. The experimental results suggest that the Fe-doped Co 3 O 4 nanofilms in this work exhibit favorable electrocatalytic activity toward ORR and appear to be promising cathodic electrocatalyst in alkaline fuel cells.

The objective of this study was to investigate the potential of methoxy polyethylene glycol (mPEG) grafted chitosan (mPEG-g-CS) to be used as a drug carrier. mPEG-g-CS was successfully synthesized by one-step method with formaldehyde. The substitution degree of mPEG on chitosan was calculated by elemental analysis and was found to be (3.23 ± 0.25)%. mPEG-g-CS self-assembled micelles were prepared by ultrasonic method with the controlled size of 178.5–195.1 nm and spherical morphology. Stable dispersion of the micelles was formed with the zeta potential of 2.3–30.2 mV. 5-Fluorouracil (5-FU), an anticancer chemotherapy drug, was used as a model drug to evaluate the efficiency of the new drug delivery carrier. The loading efficiency of 5-FU was (4.01 ± 0.03)%, and the drug-loaded mPEG-g-CS self-assembled micelle showed a controlled-release effect. In summary, the mPEG-g-CS self-assembled micelle is proved to be a promising carrier with controlled particle size and controlled-release effect. Therefore, it has great potential for the application as 5-FU carriers for effective anti-tumor activity.

Ag nanoparticles (Ag NPs) supported on nitrogen-doped ordered mesoporous carbon (N-OMC) were fabricated by one-pot synthesis strategy, in which 2D hexagonally ordered mesoporous SBA-15 and aniline were used as template and carbon precursor, respectively. Furthermore, the as-prepared composite of Ag NPs supported on N-OMC (Ag NPs/N-OMC) as electrochemical sensor towards the reduction of nitrobenzene (NB) was investigated, which displayed high sensitivity, fast response and good stability. The peak current of NB increased linearly with the concentration of NB in the range from 6.62 × 10−8 to 2.60 × 10−7 mol/L and 7.97 × 10−7 to 1.12 × 10−6 mol/L, and the low detection limit of 6.61 × 10−9 mol/L (S/N = 3) was obtained. Therefore, this work provides a new pathway to design and fabricate novel N-OMC composites, which have unique characteristics and hold numerous applications in the fields of sensors, electrocatalysis and others.

An efficient sensing platform based on functionalized reduced graphene oxide (rGO) for the detection of nitro aromatic compounds was developed in this work. Firstly, rGO was functionalized with 1,3,6,8-pyrene tetra sulfonic acid sodium salt (PyTS) through π–π interaction among molecules, which could not only improve the solubility and dispersibility of the rGO in aqueous solution but also provide more binding sites for nanoparticles. Secondly, palladium nanoparticles (Pd NPs) were uniformly decorated on the functionalized rGO nanosheets with the help of sulfonic acid group. The obtained nanocomposite (marked as Pd NPs-PyTS/rGO) was then characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), X-Ray Diffraction (XRD) and Electrochemical Impedance Spectroscopy (EIS). Finally, the electrochemical sensor was built up by casting Pd NPs-PyTS/rGO on the surface of glassy carbon electrode (GCE) and electrochemical properties of the nitro aromatic compounds have been studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. The results showed that Pd NPs-PyTS/rGO modified electrode possessed higher electrocatalytic activity and sensitivity for nitrobenzene (NB). The detection limit was as low as 0.62 ppb. This may be attributed to the combination of the large surface area of rGO and effective electrocatalytic property of Pd NPs. Experimental results showed that Pd NPs-PyTS/rGO modified the electrode was a fast, simple and controllable method for electrochemical sensor.

Chromatin organization undergoes drastic reconfiguration during gametogenesis. However, the molecular reprogramming of three-dimensional chromatin structure in this process remains poorly understood for mammals, including primates. Here, we examined three-dimensional chromatin architecture during spermatogenesis in rhesus monkey using low-input Hi-C. Interestingly, we found that topologically associating domains (TADs) undergo dissolution and reestablishment in spermatogenesis. Strikingly, pachytene spermatocytes, where synapsis occurs, are strongly depleted for TADs despite their active transcription state but uniquely show highly refined local compartments that alternate between transcribing and non-transcribing regions (refined-A/B). Importantly, such chromatin organization is conserved in mouse, where it remains largely intact upon transcription inhibition. Instead, it is attenuated in mutant spermatocytes, where the synaptonemal complex failed to be established. Intriguingly, this is accompanied by the restoration of TADs, suggesting that the synaptonemal complex may restrict TADs and promote local compartments. Thus, these data revealed extensive reprogramming of higher-order meiotic chromatin architecture during mammalian gametogenesis.

In this paper, coenzyme Q10 (Ubiquinone, CoQ10) was used for the first time as a transducer to construct electrochemical biosensor for effectively detecting γ-L-glutamyl-L-cysteinyl-glycine (glutathione, GSH). CoQ10 modified electrode was fabricated by attaching its gel mixed with multi-walled carbon nanotubes (MWNTs)/ionic liquid (IL). In the optimum conditions, based on the increasing of reduction peak current of CoQ10 caused by GSH through voltammetric technology, it was found that the peak current of CoQ10 was linear with the concentration of GSH in the range from 4.0×10(-9) to 2.0×10(-7)mol L(-1) at the pH 7.00, and the limit of detection was 3.2×10(-10)mol L(-1) (S/N=3). The results revealed that this method could be used to determine GSH in actual blood samples with the superiority of excellent selectivity, high stability and sensitivity. The strategy explored here might provide a new pathway to design novel multi-function transducers for detecting GSH, which has unique characteristic and potential application in the fields of sensor and medical diagnosis.