Association of sleep quality, depressive symptoms with non suicidal self injury among rural middle school students / 中国学校卫生

Objective@#To investigate the association of sleep quality, depressive symptoms and their interaction with non suicidal self injury (NSSI) among rural middle school students, so as to provide a reference for early prevention and control of NSSI among rural middle school students.@*Methods@#A multi stage cluster sampling method was used to randomly select four rural middle schools in Xuzhou, Jiangsu Province. A total of 1 723 middle school students were investigated according to the principle of grade stratification and class random selection. Paper questionnaires (including demographic factors, Non Suicidal Self Injury Short Scale, Pittsburgh Sleep Quality Index, Patient Health Questionnare-9) were used to conduct the questionnaire survey. Logistic regression model was used to analyze the association of sleep quality, depressive symptoms and their interaction with NSSI among rural middle school students.@*Results@#Totally 30.5% of middle school students had NSSI. Univariate results showed that girls (33.0%) had a higher incidence of NSSI than boys(27.3%), and those with sleep disorders and depressive symptoms had a higher incidence of NSSI, which was 46.8%, 43.6%. The results of multivariate Logistic regression showed that the risk of NSSI in students with sleep disorder was 1.80 times that in those without sleep disorder( OR 95%CI=1.42-2.28, P <0.01). The risk of NSSI in students with depressive symptoms was 3.32 times higher than that in those without depressive symptoms( OR 95%CI=2.60-4.24, P <0.01). The interaction results showed that there was additive interaction between sleep disturbance and depressive symptoms on the occurrence of NSSI behavior in rural middle school students, and the relative excess risk, attributable proportion and synergy index were 1.80, 0.30 and 1.57, respectively.@*Conclusion@#Sleep disorder and depressive symptoms are risk factors for NSSI among rural middle school students, and there is additive interaction between them.

pH-responsive iron manganese silicate nanoparticles as T1-T2* dual-modal imaging probes for tumor diagnosis.

Magnetic resonance imaging (MRI) probes can be concentrated in tumors through grafting targeting agents. However, the clinical application of such targeted MRI probes is largely limited because specific agents are only used to target specific characteristics of cancer cells. The development of the MRI probes that can be used regardless of tumor types or their developmental stages is highly appreciated. The acidic tumor microenvironments and acidic organelles (endosomes/lysosomes) in cancer cells are universal phenomena of solid tumors, and nanoparticles can also accumulate in tumor tissues by enhanced permeability and retention (EPR) effect. Here, we reported the synthesis of pH-responsive T1-T2* dual-modal contrast agents based on iron manganese silicate (FeMn(SiO4)) hollow nanospheres, which can release Mn(2+) ions in acidic environments, exhibiting excellent ability as agents for magnetic resonance and red fluorescence imaging. MRI for mouse models revealed that the nanoprobes could accumulate in tumors via EPR effect and then distinguish tumors from normal tissues with the synergistic effect of T1 and T2* signal only 10 min after intravenous injection. Fluorescence imaging demonstrated that the nanoprobes could be endocytosed into cancer cells and located at their lower pH compartments. Moreover, the hollow nanospheres showed no obvious toxicity and inflammation to the major organs of mice, which made them attractive diagnostic agents for different types of cancers.

Multifunctional mesoporous nanoparticles as pH-responsive Fe(2+) reservoirs and artemisinin vehicles for synergistic inhibition of tumor growth.

Artemisinin (ART) is an iron-dependent anti-cancer drug. However, simultaneous delivery of hydrophobic ART and Fe(2+) ions into cancer cells remains a major challenge. Herein, we reported Fe3O4@C/Ag@mSiO2 (FCA@mSiO2) multifunctional nanocarriers which can load ART as high as 484 mg/g. Moreover, FCA@mSiO2 nanoparticles demonstrated pH-responsive Fe(2+) release, the concentration of Fe(2+) ions can reach 2.765 nmol/L in HeLa cells cultured with FCA@mSiO2 nanoparticles. The antitumor efficacy of ART-loaded FCA@mSiO2 nanoparticles measured by MTT assay was significantly enhanced compared with free ART. It was suggested that the ART-loaded FCA@mSiO2 nanoparticles are internalized by HeLa cells and located at the acidic compartments of endosomes and lysosomes, releasing Fe(2+) ions to non-enzymatically convert ART to toxic products for killing cancer cells. This result provides a way for using promising natural drugs in anti-cancer therapeutics.

Doped graphene for metal-free catalysis.

Graphene has attracted increasing attention in different scientific fields including catalysis. Via modification with foreign metal-free elements such as nitrogen, its unique electronic and spin structure can be changed and these doped graphene sheets have been successfully employed in some catalytic reactions recently, showing them to be promising catalysts for a wide range of reactions. In this review, we summarize the recent advancements of these new and interesting catalysts, with an emphasis on the universal origin of their catalytic mechanisms. We are full of hope for future developments, such as more precisely controlled doping methods, atom-scale surface characterization technology, generating more active catalysts via doping, and finding wide applications in many different fields.

The influence of N-doped carbon materials on supported Pd: enhanced hydrogen storage and oxygen reduction performance.

N-doped graphene has become an important support for Pd in both hydrogen storage and catalytic reactions. The molecular orbitals of carbon materials (including graphene, fullerene, and small carbon clusters) and those of the supported Pd species will hybrid much stronger as N dopants are introduced, owing to the increased electrostatic attraction at the interface. This enhances the carbon substrates' catching force for the supported Pd, preventing its leaching and aggregation in many practical applications. The better dispersion and stabilization of Pd nanoparticles, which are induced by various carbon supports with N-doping, are pleasing to us and could increase their efficiency and facilitate their recycling during various reaction processes in several fields.

Synthesis of sulfonic acid-functionalized Fe3O4@C nanoparticles as magnetically recyclable solid acid catalysts for acetalization reaction.

The Fe3O4@C core-shell magnetic nanoparticles with an average size of about 190 nm were synthesized via a one-pot solvothermal process using ferrocene as a single reactant. The sulfonic acid-functionalized Fe3O4@C magnetic nanoparticles were obtained by grafting the sulfonic groups on the surface of Fe3O4@C nanoparticles to produce magnetically recyclable solid acid catalysts. The as-prepared products were characterized by X-ray diffraction and transmission electron microscopy. The catalytic performance of the as-prepared catalysts was examined through the condensation reaction of benzaldehyde and ethylene glycol. The results showed that the catalysts exhibited high catalytic activity with a conversion rate of 88.3% under mild conditions. Furthermore, catalysts with a magnetization saturation of 53.5 emu g(-1) at room temperature were easily separated from the reaction mixture by using a 0.2 T permanent magnet and were reused 8 times without any significant decrease in catalytic activity.

Improved performance of graphene doped with pyridinic N for Li-ion battery: a density functional theory model.

The performance of N-doped graphene on Li-ion battery has been investigated systematically by means of a density functional theory method. Pyridinic N doping, graphitic N atoms and 5-8-5 double vacancies have been selected as the functional defects to study their influence on Li storage compared to the pristine graphene. It has been confirmed that introducing pyridinic N atoms with p-type doping is a suitable method, especially for graphene doped with 4 pyridinic N atoms, whose structural distortion induced by Li intercalation is small and supplies strong force for Li adsorption. The diffusion barrier for this model is lower than for pristine graphene, both for the side and center diffusion routes, contributing to the high mobility. In addition, we point out that the strong catch force for Li will cause more Li to stay on the pyridinic N-doped graphene during the charge-discharge cycles, leading to a faster decrease of capacity compared to pristine graphene.

Yolk-type Au@Fe3O4@C nanospheres for drug delivery, MRI and two-photon fluorescence imaging.

Nearly monodispersed yolk-type Au@Fe3O4@C nanospheres with hollow cores of 50 nm in diameter were prepared through coating Au@SiO2 nanoparticles with Fe3O4@C double layers, followed by dissolving SiO2. The cytotoxicity of the nanospheres was evaluated by MTT assay, demonstrating a high biocompatibility. The yolk-type nanospheres show a high DOX loading content of 1237 mg g(-1). The coexistence of Fe3O4 and Au also makes the nanospheres as dual probes for MR imaging with a specific relaxivity (r2*) of 384.38 mM(-1) s(-1) and optical fluorescence imaging using a near-infrared (NIR) excitation.

Multifunctional Fe3O4@C@Ag hybrid nanoparticles as dual modal imaging probes and near-infrared light-responsive drug delivery platform.

Multifunctional nanocarriers based on Fe(3)O(4)@C@Ag hybrid nanoparticles with a diameter of 200 nm were fabricated by a facile method. Silver (Ag) nanoparticles were deposited onto the surface of Fe(3)O(4)@C nanospheres in dimethyl formamide (DMF) solution by reducing silver nitrate (AgNO(3)) with glucose. The nanocarriers of doxorubicin (DOX) with a high loading content of 997 mg/g and near-infrared (NIR) light-responsive drug delivery based on Ag nanoparticles were realized. Strong fluorescence can be observed in cell nucleus due to the presence of DOX after irradiated by NIR, and most cells were in the state of apoptosis, which indicates NIR-regulated drug release was realized. Moreover, measurements show that the nanocarriers could also be used as magnetic resonance imaging (MRI) contrast agents and fluorescent probes. The combination of synergistic NIR controlled drug release and dual modal imaging of MRI and two-photon fluorescence (TPF) imaging could lead to a potential multifunctional system for biomedical diagnosis and therapy.

Synthesis of carbon-coated, porous and water-dispersive Fe3O4 nanocapsules and their excellent performance for heavy metal removal applications.

Porous Fe(3)O(4)@C nanocapsules with a diameter of about 120 nm (about 50 nm cavity) were synthesized by combining a sacrificial template method with solvothermal treatment. The N(2) adsorption-desorption isotherms reveals their mesoporous structure and large BET surface area (159.8 m(2) g(-1)). The magnetic investigation indicates their superparamagnetic nature and high saturation magnetization (55.93 emu g(-1)). The nanocapsules also exhibit negative zeta potential (-27.59 mV) and possess carboxyl groups on the outer carbon layer, which keeps them highly dispersive in aqueous solution and provides a chelating function for metal ions. The heavy metals removal test demonstrates the excellent affinity of nanocapsules, the high efficiency for different metals (>90%), 79 mg g(-1) adsorption capacity for Pb(2+) and ultrafast removal process (Pb(2+), 99.57% within 1 minute). Protected by a porous carbon layer, the nanocapsules display excellent acidic resistance and adsorption properties even in an acidic solution (pH = 3). Moreover, the metal ions can be easily adsorbed and desorbed through manipulating the pH value for adsorbent regeneration and heavy metal recycling.

Carboxyl and negative charge-functionalized superparamagnetic nanochains with amorphous carbon shell and magnetic core: synthesis and their application in removal of heavy metal ions.

This communication describes carboxyl-functionalized nanochains with amorphous carbon shell (18 nm) and magnetic core using ferrocene as a single reactant under the induction of an external magnetic field (0.40 T), which shows a superparamagnetic behavior and magnetization saturation of 38.6 emu g(-1). Because of mesoporous structure (3.8 nm) and surface negative charge (-35.18 mV), the nanochains can be used as adsorbent for removing the heavy metal ions (90%) from aqueous solution.

Magnetically separable Prussian blue analogue Mn3[Co(CN)6]2·nH2O porous nanocubes as excellent absorbents for heavy metal ions.

The application of Prussian blue analogue (PBA) Mn(3)[Co(CN)(6)](2)·nH(2)O porous nanocubes as absorbents for heavy metal ions has been demonstrated. The result indicates that Mn(3)[Co(CN)(6)](2)·nH(2)O porous nanocubes with average diameter of 240 nm possess excellent adsorption efficiency for Pb(2+) ions (94.21% at initial Pb(2+) concentration of 10 mg L(-1)). Moreover, Mn(3)[Co(CN)(6)](2)·nH(2)O porous nanocubes can also show high adsorption efficiency on heavy metal ions even in a strong acidic solution due to its chemical stability. Notably, an external magnet could be used to accelerate the separation of Mn(3)[Co(CN)(6)](2)·nH(2)O from the treated solution. It is suggested that the high adsorption efficiency may derive from the large surface area, M(3)(II)[M(III)(CN)(6)](2)·nH(2)O porous framework structure and affinity between polarizable π-electron clouds of the cyanide bridges and heavy metals ions.

Improved surface-enhanced Raman scattering on micro-scale Au hollow spheres: synthesis and application in detecting tetracycline.

Au nanoparticles (NPs) forming a Au shell are coated on the surfaces of Ni microparticles (MPs) through a simple redox-transmetalation reaction, forming Ni/Au core-shell MPs. Then Au hollow spheres (HSs) are prepared by etching the Ni core in 1 mol L(-1) HCl solution. Surface-enhanced Raman scattering (SERS) spectroscopy signals of typical analytes such as rhodamine 6G (R6G) are observed on micro-scale Au HSs, even though the concentration of the analyte is as low as 10(-15) mol L(-1) (R6G). The Au HSs are also applied to detect tetracycline (TC), and a strong SERS signal is observed with the TC concentration of 0.1 µg L(-1). The quantitative analysis can be performed at 1595 and 1320 cm(-1), and a good linear response is also obtained. This work provides a potential and unique technique to detect broad-spectrum polyketide antibiotics in the future, and the detection of TC in foods and milk can also be performed using this SERS-based Au HSs substrate, which will benefit human health.

Prussian Blue Analogue Mn3[Co(CN)6]2·nH2O porous nanocubes: large-scale synthesis and their CO2 storage properties.

Prussian Blue Analogue (PBA) Mn(3)[Co(CN)(6)](2)·nH(2)O porous nanocubes were successfully synthesized in high yield at room temperature in the presence of poly(vinylpyrrolidone) (PVP) and characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The effects of synthetic parameters such as surfactant, the ratio of different solvents on the morphology and size of the particles were investigated. The experimental results showed that poly(vinylpyrrolidone) (PVP) and solvent ethanol play critical roles in the formation of uniform porous nanocubes. N(2) adsorption properties indicated that the Mn(3)[Co(CN)(6)](2) porous nanocubes with an average diameter of 240 nm possessed a high surface area of 675 m(2) g(-1) with total volume of 0.354 cm(3) g(-1). Moreover, the porous nanocubes showed high CO(2) adsorption at room temperature and 1 bar of pressure. To our knowledge, this is the first report on the synthesis of Mn(3)[Co(CN)(6)](2) nanomaterials and their CO(2) adsorption applications at the nanoscale.

Assembly of superparamagnetic colloidal nanoparticles into field-responsive purple Bragg reflectors.

This communication demonstrates the assembly of superparaferromagnetic colloidal nanoparticles into one-dimensional (1D) nanochain structures using an external magnetic field at room temperature, which were surrounded and linked by the amorphous carbon on the surface of nanoparticles. It is suggested that these nanochains have a fixed distance between adjacent colloidal particles and can diffract purple visible light (404 nm) under the induction of an external magnetic field.

Carboxyl-functionalized nanoparticles with magnetic core and mesopore carbon shell as adsorbents for the removal of heavy metal ions from aqueous solution.

This communication demonstrates superparamagnetic nanosized particles with a magnetic core and a porous carbon shell (thickness of 11 nm), which can remove 97% of Pb(2+) ions from an acidic aqueous solution at a Pb(2+) ion concentration of 100 mg L(-1). It is suggested that a weak electrostatic force of attraction between the heavy metal ions and the nanoparticles and the heavy metal ions adsorption on the mesopore carbon shell contribute most to the superior removal property.

Synthesis of carbon-encapsulated superparamagnetic colloidal nanoparticles with magnetic-responsive photonic crystal property.

The core/shell structure of magnetite/carbon colloidal nanoparticles (CNPs) with average size about 190 nm has been prepared via a one-step solvothermal process using ferrocene as a single reactant. The composition, phase, and morphology of the nanostructure have been characterized by X-ray diffraction, and transmission electron microscopy. Magnetic measurements reveal the superparamagnetic nature of the material with a magnetization saturation of 40.2 emu/g at room temperature. Under the induction of an external magnetic field, strong diffraction in the visible light spectrum can be observed in a suspension of CNPs in ethanol and the diffraction wavelength varies with the strength of the external magnetic field. After being stored for eight months in an ethanol solution, these CNPs can still diffract visible lights when a magnetic field was applied, which is attributed to carbon coating and creating carboxyl groups on the surface of carbon shells introducing both a steric hindrance and electrostatic repulsions between magnetite nanoparticles.

Synthesis of necklace-like magnetic nanorings.

Necklace-like magnetite and maghemite nanorings, composed of magnetic nanoparticles (NPs) with average size about 40 nm, have been prepared via a solvothermal process in a colloidal solution by a self-assembly process. The composition, phase, and morphology of these nanorings have been characterized by X-ray diffraction, X-ray absorption, and transmission electron microscopy. In this paper, we discuss the influence of reaction conditions on the formation of nanorings structure including the amount of PVP in starting materials, reaction time, and temperature. On the basis of experimental observation, we supposed that magnetite NPs may first assemble into chains by magnetic dipole-dipole interactions. These dipolar chains, which are metastable structures relative to necklace-like nanorings, then produced the rings. So, the stability of chains may determine the yield, size, and morphologies of necklace-like nanorings.

Magnetic-field-induced formation of one-dimensional magnetite nanochains.

Magnetite nanoclusters with an average size of about 120 nm have been prepared and allowed to self-assemble into one-dimensional (1D) nanochain structures with the average length about of 2 mum by a simple magnetic-field-induced (MFI) assembly approach (0.20 T). The constituent, phase, and morphology of these 1D nanochains have been characterized by X-ray diffraction and transmission electron microscopy. Magnetic measurement reveals that these 1D nanochains are weakly ferromagnetic at room temperature. In this paper, we discuss the influence of magnetization time and strength of external magnetic field on the formation of 1D nanochains. We also show that, by changing the amount of hydrogen peroxide in the starting materials, 1D nanochains with different interparticle spacing can be obtained. This 1D nanochain structure with different interparticle spacing would be an ideal system for the further study of magnetization properties of 1D ordered magnetic nanostructures.

2-(Pyrimidin-2-ylsulfan-yl)acetic acid.

The mol-ecule of the title compound, C(6)H(6)N(2)O(2)S, lies on a crystallographic mirror plane with the methyl-ene H atoms related by mirror symmetry. In the crystal packing, mol-ecules are linked into layers by inter-molecular O-H⋯N and C-H⋯O hydrogen bonds.