Search

To determine whether singleton pregnancy achieved after preimplantation genetic testing (PGT) is associated with a higher risk of adverse perinatal outcomes than in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) singleton pregnancy.A retrospective cohort study.A university-affiliated fertility center.This cohort study included singleton live births resulting from PGT (n = 232) and IVF/ICSI singleton pregnancies (n = 2,829) with single frozen-thawed blastocyst transfer. Multiple baseline covariates were used for propensity score matching, yielding 214 PGT singleton pregnancies matched to 617 IVF/ICSI singleton pregnancies.Trophectoderm biopsy.The primary outcome was gestational hypertension, and various clinical perinatal secondary outcomes related to maternal and neonatal health were measured.Compared with IVF/ICSI singleton pregnancy, PGT singleton pregnancy was associated with a significantly higher risk of gestational hypertension (adjusted odds ratio, 2.58; 95% confidence interval, 1.32, 5.05). In the matched sample, the risk of gestational hypertension remained higher with PGT singleton pregnancy (odds ratio, 2.33; 95% confidence interval, 1.04, 5.22) than with IVF/ICSI singleton pregnancy. No statistical differences were noted in any other measured outcomes between the groups.The perinatal outcomes of PGT and IVF/ICSI singleton pregnancies were similar except for the observed potentially higher risk of gestational hypertension with PGT singleton pregnancy. However, because the data on PGT singleton pregnancies are limited, this conclusion warrants further investigation.

Transient Receptor Potential Melastatin-2 (TRPM2) is a nonselective cation channel mediating Ca2+ influx in response to oxidative stress. Given that insulin resistance-related endothelial dysfunction in obesity attributes to fatty-acid-induced reactive oxygen species (ROS) overproduction, in this study, we addressed the possible role of TRPM2 in obesity-related endothelial insulin resistance and the underlying mechanisms. Whole-cell patch clamp technique, intracellular Ca2+ concentration measurement, western blot, vasorelaxation assay, and high-fat diet (HFD)-induced obese model were employed to assess the relationship between TRPM2 and endothelial insulin response. We found that both the expression and activity of TRPM2 were higher in endothelial cells of obese mice. Palmitate rose a cationic current in endothelial cells which was inhibited or enlarged by TRPM2 knockdown or overexpression. Silencing of TRPM2 remarkably improved insulin-induced endothelial Akt activation, nitric oxide synthase (eNOS) phosphorylation and nitric oxide (NO) production, while TRPM2 overexpression resulted in the opposite effects. Furthermore, TRPM2-mediated Ca2+ entry, CaMKII activation and the following activation of PERK/ATF4/TRB3 cascade were involved in the mechanism of obesity or palmitate-induced endothelial insulin resistance. Notably, in vivo study, knockdown of TRPM2 with adeno-associated virus harboring short-hairpin RNA (shRNA) against TRPM2 alleviated endothelial insulin resistance and ameliorated endothelium-dependent vasodilatation in obese mice. Thus, these results suggest that TRPM2-activated Ca2+ signaling is necessary to induce insulin resistance-related endothelial dysfunction in obesity. Downregulation or pharmacological inhibition of TRPM2 channels may lead to the development of effective drugs for treatment of endothelial dysfunction associated with oxidative stress state.

Uncontrollable vascular smooth cell proliferation is responsible for vascular remodeling during hypertension development. Glyoxalase 1 (GLO1), the major enzyme detoxifying methylglyoxal, has a critical role in regulating proliferation of several cell types. However, little is known whether GLO1 is involved in cerebrovascular remodeling and basilar smooth muscle cell (BASMC) proliferation during hypertension. Here we explored the role of GLO1 in angiotensin II (Ang II)-induced cerebrovascular remodeling and proliferation of BASMCs and the underlying mechanisms. The protein expression of GLO1 in basilar arteries from hypertensive mice was decreased, and GLO1 expression was negatively correlated with medial cross-sectional area and blood pressure in basilar arteries during hypertension. Knockdown of GLO1 promoted while overexpression of GLO1 prevented Ang II-induced cell proliferation and cell cycle transition in BASMCs. These results were related to the inhibitory effects of GLO1 on PI3K/AKT/CDK2 cascade activation upon Ang II treatment. In addition, in vivo study, GLO1 overexpression with adeno-associated virus harboring GLO1 cDNA improved cerebrovascular remodeling in basilar artery tissue during Ang II-induced hypertension development. These data indicate that GLO1 reduction mediates cerebrovascular modeling via PI3K/AKT/CDK2 cascade-dependent BASMC proliferation. GLO1 acts as a negative regulator of hypertension-induced cerebrovascular remodeling and targeting GLO1 may be a novel therapeutic strategy to prevent hypertension-associated cardiovascular complications such as stroke.

In this work, a novel Cu(I) coordination polymer, Cu2LBr2 (1) based on a pyridyl-functionalized resorcin[4]arene [L = (2,8,14,20-tetraethyl-4,10,16,22-tetra kis((2-pyridylmethylene)oxy)-6,12,18,24-tetramethoxy-resorcin[4]arene)] has been synthesized under solvothermal condition. 1 was characterized by various physicochemical analyses and it shows a ribbon structure. Notably, 1 exhibits an outstanding thermal stability. 1 possesses strong luminescent property, and can selectively probe Cr2O72−, MnO4− and nitrobenzene via luminescent quenching. In addition, 1 is an efficient catalyst for azide–alkyne cycloaddition reaction.

Homeobox 1 in Malus×domestica (MdHB-1) is a transcription factor that belongs to homeodomain-leucine zipper I (HD-Zip I) protein subfamily. According to previous reports, MdHB-1 could regulate ethylene synthesis by binding with the MdACO1 promoter, but other functions of MdHB-1 are still unknown. To reveal more clues concerning the characters of the MdHB-1 gene promoter and the functions of MdHB-1, the promoter region of MdHB-1 was cloned from the Royal Gala apple genome and recombined with the β-glucuronidase (GUS) gene in this study. This research was conducted in Nicotiana tabacum and supported by Agrobacterium-mediated transient transformation and bioinformatics analysis. Deletion analysis of the MdHB-1 promoter showed that the GUS gene could be activated by serially deleted promoters, and the activity promoted by 680 nucleotides (nt) was the lowest. The region, which is 266 nt upstream of the initiation code (ATG), was effective for GUS expression. Meanwhile, the activity of the MdHB-1 promoter (−1 057 nt), which was stronger than MdHB-1 promoter (−1 057 to −266 nt) and lack the 5′-untranslated region (5′-UTR), showed that 5′-UTR may have a positive effect on gene transcription. After the sequence analysis, the cis-acting elements that respond to hormones and environmental stresses were identified in the promoter region. The MdHB-1 promoter (1 057 nt) activity in Nicotiana tabacum was positively induced by ethrel and darkness, and it was suppressed by gibberellic acid (GA), whereas abscisic acid (ABA), salicylic acid (SA), wounding, and Pseudomonas syringae pv. tomato (DC3000) treatments revealed a slight auxo-action. These results reveal that the MdHB-1 promoter receive internal or external signals, and MdHB-1 may refer to many biological activities in apple, such as its stress response, development, and ripening.

Not only for utilizing both ultraviolet (UV) and visible light but also for enhancing photoinduced carriers separation capability, a composite photocatalyst composed of graphite-like carbon nitride (g-C 3 N 4 ) and TiO 2 has been successfully prepared by an acetic acid assisted sol–gel method combined with calcination process. The as-prepared g-C 3 N 4 /TiO 2 composite photocatalyst was characterized by using XRD, SEM, TEM, XPS, FT-IR spectra, UV-DRS and TGA. Combined XRD results with SEM images, it indicated that the obtained anatase TiO 2 nanoparticles dispersed well on the surface of g-C 3 N 4 sheets and the aggregation degree of TiO 2 nanoparticles could be effectively alleviated due to the introduction of g-C 3 N 4 . The results of UV-DRS further displayed that the optical absorption edge of g-C 3 N 4 /TiO 2 composites had an obvious red shift to the longer wavelength in comparison with pure TiO 2 . Profiting from the above-mentioned advantages, g-C 3 N 4 /TiO 2 composite showed excellent photocatalytic performance. Under visible light irradiation, all g-C 3 N 4 /TiO 2 composite samples had more excellent photodegradation performance than pure g-C 3 N 4 or TiO 2 , and the pseudo-first-order kinetic constant of methyl orange (MO) degradation on optimal g-C 3 N 4 /TiO 2 composite was 2.80 times as great as that on pure g-C 3 N 4 . The photodegradation performance of optimal g-C 3 N 4 /TiO 2 composite was also investigated under UV–vis light irradiation. Compared with the pure phase (TiO 2 or g-C 3 N 4 ), the composite photocatalytic capability was remarkably enhanced by coupling TiO 2 with g-C 3 N 4 , which mainly benefited from the effective separation of photoinduced electron–hole pairs and the extended optical absorption range, both owing to the heterojunction built-in between g-C 3 N 4 and TiO 2 .

Inter-regional transmission has always been taken as an important measure to better the power mix in China, however, not all the people think it effective in boosting the development of clean power because quite many intensively invested transmission lines are not fully occupied. To objectively evaluate the impacts of the introduction of inter-regional transmission lines, especially the ultra-high voltage (UHV) grid, may clarify the disputes and benefit China’s electricity policy reform. This work simulates an equilibrium model of China’s electricity market through the mixed complementarity problems (MCP) method, to investigate the impacts of the construction of the UHV transmission lines on the deployment of clean power and reduction of carbon emissions under different scenarios. The results indicate that the introduction of the UHV grid has increased the competition in both power generation and consumption sides, but it has limited contribution to mitigate the curtailment of clean power and carbon emissions, and there may exist the hysteresis effect of the UHV grid. We propose the following suggestions to better the development of China’s power system. (1) With regard to electricity market coupling, it is more appropriate to firstly connect the regional market in the central and eastern China. (2) Promoting the installed capacity of clean power in a short-run is a necessary auxiliary method to effectively reduce the carbon emissions.

In a general face recognition scenario, classifications attend to assign a label to a single probe image. So far a branch of classification methods, which assume that a probe image tends to lie on the same class-specific subspace as the gallery images from the same class, have drawn wide attention for their good performance. Actually, those linear regression based classifications are sufficient to achieve promising recognition accuracy. However if there are wide ranges of variations on probe images such as pixel noises, lighting variant, they could deviate the probe images from their correct locations in feature space. To solve this problem, we propose a new linear regression based method by generating an extended set for a probe image. In the first step of our method, we not only produce the low dimension features for a probe but also generate virtual samples by adding randomness into downsampling. The second step is to classify the probe by using canonical correlation analysis. As the generated virtual probe samples have high possibility to cover the correct location in feature space, our proposed method shows promising performance in the experiments.

This paper reported a p-NiO/n-ZnO heterostructures synthesized by a low-cost and environment-friendly strategy. X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) spectroscopy were used to characterize the as-synthesized powders. The results indicated that the p–n heterostructures formed between the cubic structure NiO and hexangular structure ZnO in the NiO/ZnO composites. Furthermore, the gas sensing performance for detection of acetone and photocatalytic activity for the degradation of methyl orange (MO) of the NiO/ZnO composites was investigated. The composites showed much higher performance than that of pure NiO and ZnO, which could be ascribed to the formation of p–n heterojunctions in the NiO/ZnO composites.

ZnO flowers functionalized by Au nanoparticles (NPs) with various Au contents have been developed. The gas sensing properties of the sensors fabricated from these materials were examined and compared at varied working temperatures. Improved sensor response, selectivity and short response and recovery times to acetone vapor were achieved by suitably modulating the weight percent of Au NPs. Experimentally, the formation of Au/ZnO hybrids and surface coarsening of ZnO flowers were found to lead to apparent further enhancement of the sensor performance.

A novel nanocomposite, comprising of graphene sheet (GS) and ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF 6 ), was developed on the glassy carbon electrode (GCE) for the simultaneous determination of hydroquinone and catechol in 0.10 M acetate buffer solution (pH 5.0). At the GS/BMIMPF 6 /GCE, both hydroquinone and catechol can cause a pair of quasi-reversible and well-defined redox peaks. In comparison with bare GCE and GS modified electrode, GS/BMIMPF 6 /GCE showed larger peak currents, which was related to the higher specific surface area of graphene and high ionic conductivity of BMIMPF 6 . Under the optimized condition, the cathodic peak current were linear over ranges from 5.0 × 10 −7 M to 5.0 × 10 −5 M for hydroquinone and from 5.0 × 10 −7 M to 5.0 × 10 −5 M for catechol, with the detection limits of 1.0 × 10 −8 M and 2.0 × 10 −8 M, respectively. The proposed method was successfully applied to the simultaneous determination of hydroquinone and catechol in artificial sample, and the results are satisfactory.

Objectives Hypophosphatasia (HPP) is an inherited disorder characterised by defective bone and tooth mineralisation and deficient serum and bone alkaline phosphatase activity, and it results from mutations in alkaline phosphatase (ALPL) encoding tissue-nonspecific alkaline phosphatase (TNAP). The objective of the present work was to explore the correlations between genotype and phenotype in a Chinese family affected by autosomal-dominant HPP. Design We examined all individuals of a HPP family by clinical and radiographic examinations as well as laboratory assays. Furthermore, a prematurely exfoliated tooth was observed histopathologically. Based on the clinical and pathological manifestations, the causative gene ALPL was selected for further analysis and screened for mutations. Results The proband presented the characteristic clinical features of childhood HPP such as rachitic skeletal changes, early loss of primary teeth, and short root anomalies of the permanent teeth. Histopathological evaluation of a tooth revealed a “shell” structure, severe mineralisation defects of dentin, and an absence of cementum. The patient's mother and grandfather were clinically diagnosed with adult HPP. The family showed autosomal-dominant moderate hypophosphatasia. DNA sequencing and analysis revealed a novel missense mutation (c.251A>T) in exon4 of ALPL. This mutation (p.E84V) is located in the secondary structure of TNAP's homodimer interface, and it was predicted to have a dominant negative effect. Conclusion Our findings suggest the missense transversion (c.251A>T, p.E84V) should be responsible for the HPP phenotype in this Chinese family.

Boric acid and kieserite were prepared from low-grade ascharite by sulfuric acid method. This method results in the recovery of 71.06% and 45.03% for boric acid and kieserite, respectively. Meanwhile, the boric acid was precipitated from the filtrate at low temperature and the solution was recycled without discharging waste liquid in the whole process. The influence of amount of sulfuric acid, mass fraction of sulfuric acid, reaction temperature and reaction time on the leaching rate of boric acid were studied. The results show that the leaching rate of boric acid reaches 93.80% under the following conditions: the amount of sulfuric acid is 85% of theoretical dosage; the mass fraction of sulfuric acid is 25%; reaction temperature is 95 °C; and the reaction time is 100 min. Meanwhile, the effects of mass fraction of magnesium sulfate, crystallization temperature and crystallization time on the crystallization of kieserite were investigated and the optimal crystallization conditions are obtained: the mass fraction of magnesium sulfate is 28%; the crystallization temperature is 180 °C and the crystallization time is 4 h.

Objectives Oligodontia is defined as the congenital absence of 6 or more permanent teeth excluding the third molar. The occurrence of non-syndromic still remains poorly understood, but in recent years some cases have been reported where mutations or polymorphisms of PAX9 and MSX1 had been associated with non-syndromic oligodontia. The objective of the present work was to study the phenotype and genotype of three generations of a Han Chinese family affected by non-syndromic autosomal-dominant oligodontia. Design We examined all individuals of the oligodontia family by clinical and radiographic examinations. Based on clinical manifestations, candidate genes MSX1 and PAX9 were picked up to analyse and screen mutations. Results Dental evaluation showed that the most commonly missing teeth are the mandibular second premolars, followed by the maxillary second premolars and maxillary lateral incisors, and subsequently the maxillary first premolars. The probability of missing a particular type of tooth is not always bilaterally symmetrical, and differences exist between maxilla and mandible. PCR-SSCP analysis and DNA sequencing revealed a novel missense mutation c.662C>A in a highly conserved homeobox sequence of MSX1 and a known polymorphisms c.347C>G. Conclusion Our finding suggests the missense transversion (c.662C>A) and the polymorphisms (c.347C>G) may be responsible for oligodontia phenotype in this Chinese family.

New unsaturated polyesters of poly(fumaric acid–glycol–sebacic acid) copolymers and poly(maleic anhydride–glycol–sebacic acid) copolymers were prepared by melt polycondensation of the corresponding mixed monomers: sebacic anhydride, fumaric acid or maleic anhydride and glycol. Methyl-methacrylate (MMA) was used as crosslinker and dimer acid was used as thinner. In vitro studies showed that those copolymers are degradable in phosphate buffer at 37 °C and poly(fumaric acid–glycol–sebacic acid) has proper drug release rate as drug carriers. The biocompatibility of poly(fumaric acid–glycol–sebacic acid) copolymers under mice skin was also evaluated; macroscopic observation and microscopic analysis demonstrated that the copolymer is biocompatible and well tolerated in vivo. The injected poly(fumaric acid–glycol–sebacic acid) [molar ratio Mfumaric acid:Mglycol:Msebacic acid = 1.75:2.20:0.25] containing 5% adriamycin hydrochloride (ADM) in the mice bearing Sarcoma-180 tumor exhibited a good antitumor efficacy. The volume doubling time (VDT) (18 ± 2.5 days) of the tumor growth by this treatment was longer than that (7 ± 0.9 days) by the subcutaneous injection of ADM.

It has been shown that highly conserved residues that form crucial structural elements of the catalytic apparatus may be used to account for the evolutionary history of enzymes. Using saturation mutagenesis, we investigated the role of a conserved residue (Arg(526)) at the active site of acylaminoacyl peptidase from hyperthermophilic Aeropyrum pernix K1 in substrate discrimination and catalytic mechanism. This enzyme has both peptidase and esterase activities. The esterase activity of the wild-type enzyme with p-nitrophenyl caprylate as substrate is approximately 7 times higher than the peptidase activity with Ac-Leu-p-nitroanilide as substrate. However, with the same substrates, this difference was increased to approximately 150-fold for mutant R526V. A more dramatic effect occurred with mutant R526E, which essentially completely abolished the peptidase activity but decreased the esterase activity only by a factor of 2, leading to a 785-fold difference in the enzyme activities. These results provide rare examples that illustrate how enzymes can be evolved to discriminate their substrates by a single mutation. The possible structural and energetic effects of the mutations on k(cat) and K(m) of the enzyme were discussed based on molecular dynamics simulation studies.

An electrochemical sensor modified with multi-walled carbon nanotubes/β-cyclodextrin (MWNTs/β-CD) film was fabricated for the determination of rutin. The electrochemical behavior of rutin at the chemically modified electrode was investigated by cyclic voltammetry (CV). The response mechanism of MWNTs/β-CD film for rutin was based on the inclusion interaction of β-CD for rutin. The MWNTs/β-CD film showed preferably analytical performance characteristics in electrocatalytic oxidation and reduction for rutin compared with the MWNTs film and bare glassy carbon electrode (GCE). A linear calibration plot was obtained covering the range from 4.0 × 10−7 to 1.0 × 10−3 mol L−1 with a detection limit of 2.0 × 10−7 mol L−1. This electrochemical sensor showed excellent sensitivity, selectivity, stability and recovery for the determination of rutin in urine samples.

A compound material of multi-walled carbon nanotubes (MWNTs) coated with SnO2 was synthesized at ambient conditions. The Raman spectra, X-ray diffraction (XRD) and transmission electron microscopy (TEM) results confirmed that the existence of SnO2 nanoparticles were on the outside of the MWNTs. The gas sensing properties of the material were studied. It was found that the sensor exhibited nice sensing responses to liquefied petroleum gas (LPG) and ethanol gas (C2H5OH) and a fast response and recovery within seconds. Furthermore, the gas sensor responses increased linearly with the increment of the gas concentrations of LPG and ethanol.

An amperometric immunosensor was developed based on immobilizing antibody on the surface of modified CdFe 2 O 4 magnetic nanoparticles. The goat anti-human IgG antibody (anti-IgG) was first covalently immobilized to core–shell (CdFe 2 O 4 –SiO 2 ) magnetic nanoparticles, which were surface-modified with amino groups on the surface. The resulting bio-magnetic nanoparticles were attached to the surface of carbon paste electrode (CPE) with the help of a permanent magnet. A sandwich immunoassay was performed on the bio-magnetic nanoparticles monolayer supported by CPE. The assay comprised first loading of IgG on the bio-magnetic nanoparticles monolayer, then blocking in BSA solution, followed by incubation in anti-IgG-HRP conjugate, and finally the amperometric detection with hydroquinone as a mediator. The linear range for IgG assay was 0.51–30.17 μg ml −1 and the detection limit was 0.18 μg ml −1 . The simple manipulations of construction and low cost were main advantages of proposed immunosensing method.

n-Type semi-conductive nanometer material MgFe2O4 was synthesized by solid-state reaction of inorganic reagents MgSO4, Fe(NO3)3·9H2O, and NaOH. The process was a convenient, environment friendly, inexpensive and efficient preparation method for MgFe2O4 nanomaterial. X-ray diffraction (XRD) was used to confirm the material structure and transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) to depict the crystallite microstructure. Conductance responses of the nanocrystalline MgFe2O4 thick film were measured by exposing the film to reducing gases like methane (CH4), hydrogen sulfide (H2S), liquefied petroleum gas (LPG) and ethanol gas (C2H5OH). It was found that the sensor exhibited various sensing responses to these gases at different operating temperature. Furthermore, the sensor exhibited a fast response and a good recovery. Successive on and off responses could be repeated without observing major changes in the response signal.

An optical sensor for cetyltrimethylammonium chloride (CTAC), based on the fluorescence quenching of berberine/butylated β-cyclodextrin (HDB-β-CD) complex immobilized in plasticized poly(vinyl chloride) (PVC) membrane has been developed, in which berberine served as a sensitive fluorescence indicator probe. The decrease of fluorescence intensity of berberine/HDB-β-CD complex upon the addition of CTAC was attributed to the formation of an inclusion complex between HDB-β-CD and CTAC, which has been utilized as the basis of the fabrication of a CTAC-sensitive fluorescence sensor. The response mechanism of sensor has been discussed in detail. The analytical performance characteristics of the proposed CTAC-sensitive sensor were investigated. The sensor can be applied to the quantification of CTAC with a linear range covering from 7.0 × 10 −11 to 4.0 × 10 −9 mol L −1 with a detection limit of 3.0 × 10 −11 mol L −1 . The sensor exhibits excellent reproducibility, reversibility and selectivity. The recommended method was successfully used for the determination of CTAC in water samples.

Multilayered thin films were prepared by a layer-by-layer (LbL) deposition of sulfonated β-cyclodextrin (s-β-CD) and cationic poly(allylamine) hydrochloride (PAH) on the surface of a quartz slide. A self-assembled fluorescent host, s-β-CD/neutral red was formed by the inclusion interaction of neutral red (NR) with the s-β-CD immobilized on the multilayered films. An optical sensor for lithocholic acid (LA), based on the fluorescence quenching of s-β-CD/NR complex immobilized on the multilayered films, has been developed, in which NR served as a sensitive fluorescence indicator probe. The decrease of fluorescence intensity of s-β-CD/NR complex in the presence of LA was attributed to the formation of an inclusion complex between s-β-CD and LA, which has been utilized as the basis of the fabrication of a LA-sensitive fluorescence sensor. The response mechanism of sensor has been discussed in detail. The analytical performance characteristics of the proposed LA-sensitive sensor were investigated. The sensor can be applied to the quantification of LA with a linear range covering from 2 uM to 60 uM and a detection limit of 1 uM. The sensor exhibits excellent reproducibility, reversibility and selectivity.

Horseradish peroxidase (HRP) to a nano-Au monolayer, which was supported by PAMAM dendrimer/cystamine modified gold electrode. The high affinity of PAMAM dendrimer for nano-Au with its amine groups was used to realize the role of nano-Au as an intermediator to retain the high bioactivity of HRP. A hydrogen peroxide biosensor was fabricated based on the effective immobilization of the high bioactivity of HRP. In the presence of the hydroquinone mediator in the solution, the immobilized HRP exhibited excellent electrocatalytical response to the reduction of H 2 O 2 . The effects of various experimental variables were optimized. The resulting biosensor showed a linear response to H 2 O 2 over a concentration range from 1 × 10 −5 to 2.5 × 10 −3 mol L −1 with a sensitivity of 0.53 A L mol −1 cm −2 and a detection limit of 2.0 μmol L −1 based on a signal-to-noise ratio of 3. The apparent Michaelis-Menten constant ( K m app ) of the biosensor was evaluated to be 0.52 mmol L −1 . The biosensor exhibited high sensitivity and good stability and reproducibility. Performance of the biosensor was evaluated with respect to possible interferences and the application to real sample analysis.

A phenol biosensor was developed based on the immobilization of tyrosinase on the surface of modified magnetic MgFe2O4 nanoparticles. The tyrosinase was first covalently immobilized to core-shell (MgFe2O4–SiO2) magnetic nanoparticles, which were modified with amino group on its surface. The resulting magnetic bio-nanoparticles were attached to the surface of carbon paste electrode (CPE) with the help of a permanent magnet. The immobilization matrix provided a good microenvironment for the retaining of the bioactivity of tyrosinase. Phenol was determined by the direct reduction of biocatalytically generated quinone species at −150 mV versus SCE. The resulting phenol biosensor could reach 95% of steady-state current within 20 s and exhibited a high sensitivity of 54.2 μA/mM, which resulted from the high tyrosinase loading of the immobilization matrix. The linear range for phenol determination was from 1 × 10−6 to 2.5 × 10−4 M with a detection limit of 6.0 × 10−7 M obtained at a signal-to-noise ratio of 3. The stability and the application of the biosensor were also evaluated.

An electrochemical sensor for cinchonine (CCN) using the β-cyclodextrin (β-CD) modified poly(N-acetylaniline) (PAA) electrode has been developed, in which 1,4-hydroquinone (HQ) was chosen as a probe. Complexation of HQ with β-CD modified on the glassy carbon electrode (GCE) was examined by cyclic voltammetry (CV). HQ was included in the cavity of β-CD and reversible voltammograms were observed. In the presence of CCN, a competitive inclusion equilibrium with β-CD was established between HQ and CCN, lowering the peak current of HQ. The decrease in the peak current of HQ is directly proportional to the amount of CCN. Linear calibration plot was obtained over the range from 4.0 × 10−6 to 8.0 × 10−5 M with a detection limit (S/N = 3) of 2.0 × 10−6 M. From the inhibitory effect of CCN on the inclusion of HQ by β-CD, the apparent formation constant of CCN with the immobilized β-CD was estimated. This electrochemical sensor showed excellent sensitivity, repeatability, stability and recovery for the determination of CCN. The response mechanism of the sensor was discussed in detail. The optimum steric configuration of inclusion complex was presented by molecular dynamics simulation.

The effect of Pt on gas sensing properties of nano-crystalline CdSnO 3 , a semiconducting oxide with perovskite structure, was studied. CdSnO 3 was prepared by solid-state reaction of inorganic reagents 3CdSO 4 ·8H 2 O, SnCl 4 ·5H 2 O and NaOH. The thermal analysis was detected by means of thermogravimetric-differential thermal analysis (TG-DTA). XRD was used to confirm the material structure and TEM to depict the crystallite microstructure and the specific surface area was measured by Brunaur–Emmett–Teller (BET) method. Noble metal additive Pt of different concentrations from 0.1 to 2 at.% was incorporated into CdSnO 3 by impregnation technique. Conductance responses of the nano-crystalline CdSnO 3 thick films were measured by exposing the films to C 2 H 5 OH, CO, CH 4 , C 4 H 10 , gasoline and LPG at different operating temperatures. It was found that sensors doped with Pt exhibited good sensitivity and selectivity to the vapor of C 2 H 5 OH and the optimum sensitivity is obtained with the sensor doped with 1.5 at.% Pt.

A surface treated nanoporous ZrO2/Chitosan composite matrix was developed to fabricate the glucose biosensor. This material combined the advantages of inorganic nanoparticles, ZrO2, and organic polymer, Chitosan. Glucose oxidase immobilized in the material maintained its activity well as the usage of glutaraldehyde was avoided. The activity of enzyme was 5.02 times greater than the cross-linked enzyme. The interaction between ZrO2/Chitosan and enzyme was characterized with FT-IR spectroscopy. The results of transmission electron microscopy of surface-treated ZrO2/Chitosan film showed that the matrix was porous and highly homogeneous. The parameters affecting the fabrication and experimental conditions of biosensors were optimized. The biosensor had a fast response of less than 10 s. The linear range was 1.25 × 10−5 to 9.5 × 10−3 M with a detection limit of 1.0 × 10−5 M at 3σ and a sensitivity of 0.028 μA mM−1. The biosensor retained about 75.2% of its original response after one-month storage in a phosphate buffer.

The paper reports the preparation and gas sensing characteristic of NiFe 2 O 4 nanopowder with and without different noble metal dopants such as Au, Pt, Pd. Ultrafine NiFe 2 O 4 powders were prepared by solid-state reaction of inorganic reagents, Ni(Ac) 2 , Fe(NO 3 ) 3 , and NaOH. XRD and Raman spectrometer were used to confirm the material structure and TEM to depict the crystallite microstructure. Au, Pd and Pt with different concentration were incorporated into NiFe 2 O 4 by impregnation technique. The electrical resistance response to H 2 S gas of the sensors based on the materials was investigated at different operating temperature and different gas concentrations. The results show that NiFe 2 O 4 is a p-type semiconductor and the sensor response of the doped NiFe 2 O 4 sensors was superior to that of the undoped ones. The sensor response increased linearly with the H 2 S gas concentration up to 100 ppm. The sensor with the 1.5 wt.% Au doped NiFe 2 O 4 showed excellent electrical resistance response towards 5 ppm H 2 S gas and the sensor response was up to 35.8 at 300 °C. The 1.5 wt.% Pt doped one was less sensitive to H 2 S but work at lower temperature, 240 °C. The gas-sensing behavior of these materials with respect to various reducing gases like liquefied petroleum gas (LPG), methane (CH 4 ), carbon monoxide (CO), butane (C 4 H 10 ) and hydrogen gas (H 2 ) suggested that the H 2 S gas sensor developed possesses an excellent selectivity. The interaction mechanism and correlations between the electrical resistance response and noble metal dopants were discussed.

A novel protein A (PA)-based strategy for the orientation-controlled immobilization of antibodies using nanometer-sized gold (Nano-gold) particles and an amine-terminated plasma-polymerized film (PPF) has been proposed. A quartz crystal microbalance was fabricated, accordingly, coupling with haptoglobin (HP) antibody followed by HP immunoassay, as a model test system. The crystal was modified with plasma-polymerized n-butyl amine film to deposit Nano-gold particles and PA, on which HP antibodies were immobilized. The surface topology of the as-prepared crystal was characterized by use of scanning electron microscopy. In contrast to the traditional flat gold surface, the assembled Nano-gold particle monolayer could allow PA molecules bound with higher bioactivity and loading amount (density), achieving better antibody-binding capabilities. Results indicate that immunosensors prepared using the developed PPF-Nano-gold-PA binding procedure exhibit increased analytical performance compared with those produced using the direct PA binding procedure and the PPF-based glutaraldehyde cross-linking procedure. A HP serum concentration as low as 0.41 nM can be determined by this new system. Regenerated simply by rinsing in the acid buffer, the proposed sensor can achieve up to 11 assay cycles without significant loss of sensitivity.

In the present study, pseudoginsenoside-F(11) (PF(11)), a saponin that existed in American ginseng, was studied on its protective effect on methamphetamine (MA)-induced behavioral and neurochemical toxicities in mice. MA was intraperitoneally administered at the dose of 10 mg/kg four times at 2-h intervals, and PF(11) was orally administered at the doses of 4 and 8 mg/kg two times at 4-h intervals, 60 min prior to MA administration. The results showed that PF(11) did not significantly influence, but greatly ameliorated, the anxiety-like behavior induced by MA in the light-dark box task. In the forced swimming task, PF(11) significantly shortened the prolonged immobility time induced by MA. In the appetitively motivated T-maze task, PF(11) greatly shortened MA-induced prolonged latency and decreased the error counts. Similar results were also observed in the Morris water maze task. PF(11) significantly shortened the escape latency prolonged by MA. There were significant decreases in the contents of dopamine (DA), 3,4-dihydroxyphenacetic acid (DOPAC), homovanillic acid (HVA), and 5-hydroxyindoacetic acid (5-HIAA) in the brain of MA-treated mice. PF(11) could partially, but significantly, antagonize MA-induced decreases of DA. The above results demonstrate that PF(11) is effective in protection of MA-induced neurotoxicity and also suggest that natural products, such as ginseng, might be potential candidates for the prevention and treatment of the neurological disorders induced by MA abuse.