Obesity is a huge burden of the world. It is commonly recognized that dietary structure and physical inactivity is essential in the progress of obesity. However, some individuals still face the trouble of obese even though they live a healthy life. Except for the combination of diseases, the operation of both lifestyle and genetic features contributes to obesity. Melanocortin-4-receptor (MC4R) gene is one of the known hereditary factors of obesity. rs17782313, a single nucleotide variant in MC4R gene, has been reported unclear results in whether it plays a role in obesity. This meta-analysis is to estimate the association between MC4R rs17782313 genotype and obesity. A systematic literature retrieval was conducted in four databases: PubMed, Embase, Web of Science and Cochrane Library with specific search strategy. Select qualified studies to identify relevant studies. Odds ratios (ORs) with 95% confidence intervals (CI), P value and I2 value were used to assess the strength of the association in meta-analysis and adjusted with ethnicity, quality and single nucleotide polymorphism (SNP) testing method. 6 eligible studies involving 3133 obese cases and 3123 normal-weight participants were selected from 378 articles. Allele B of MC4R rs17782313 present a statistically significant association with obesity under allele contrast model (OR = 1.325, 95%CI: 1.219–1.439), dominant model (OR = 1.320, 95%CI: 1.184–1.472), recessive model (OR = 1.690, 95%CI: 1.420–2.011) and homozygous type of co-dominant model (OR = 1.925, 95%CI: 1.590–2.330), respectively, and P < 0.05. Mutated MC4R rs17782313 is associated with higher risk of obesity. People with homozygous mutant genotype of MC4R rs17782313 would be more likely to suffer from obesity, while heterozygous mutant genotype needs further studies to clarify.

For studying impact on electric field intensity of composite insulator caused by erosion of acid dip mixture,this paper discusses establishment of composite insulator acid dip mixture erosion model which uses finite element method to proceed simulating calculation for electric field intensity and potential distribution before and after erosion.The result shows under the role of erosion of acid dip mixture,serious distortion occurs to electric field intensity and potential distribution.Partial electric field intensity of umbrella skirt is exceeding 53.7%than normal value while the voltage value of single umbrella skirt exceeds about 1 175 V than normal value which may cause serious hidden danger to safe and reliable operation of composite insulator.

Security threats for voice-over IP (VoIP) networks are becoming a major concern as its popularity increases. New attacks are developed that target directly the underlying SIP protocol. To detect such kinds of attacks we present a specification-based detection framework to recognise deviation from its expected behaviour. We present an implementation and show with measurements that this method is capable of attack detection and mitigation for different kinds of attacks directed towards a SIP infrastructure, including denial-of-service message flooding.

A CCD multi-channel spectroscopic instrument was used to measure the spectrum signal of the arc plasma, and the multi-wavelength spectrum for Ag/LaFe1-xNixO3-delta contact was obtained. Using this Spectroscopy diagnostics, the influences of the input power, the frequency and the gap of contact on arc plasma were investigated. The best work condition for Ag/LaFe1-xNixO3-delta contact material was found. The results will provide the testing of the contact material performances with an effective diagnostics way.

A spectroscopic measuring system was described and developed to analyze the time-varying optical spectra of electrical contacts. A simulaton system of contact life, a monochromator, a photomultiplier tube (CR114) and a four channel digital storage oscillograph are used as optical detectors, so that the precise and quick measurements can be made for the spectrums with tim. At the same time, arc voltage waveform is measured for the breaking arc at the source voltage E of 24 V and the closed contact current I of 18 A. It is shown that this system can be applied to analyse the electric arc light and voltage for spectrums, and the dynamic characteristic of the breaking arc on Ag and Ag/MeO electric contacts.

The resistance, mass transfer, erosion and arc properties of a new contact material named Ag/LaFe1-xNixO3 conductive ceramics were investigated. Ag/LaFe1-xNixO3 performed well under low voltage conditions in contrast with other contact materials such as Ag/CdO and Ag/SnO2. After 5000 make-and-break operations, life test was made and the surface analysis method together with an arc voltage waveform was used to research the corrosion resisting and mass transfer properties. It was found that the conductive ceramics used in the contact materials could influence the resistance performance and, in turn, influence the mass transfer, erosion and arc characteristics.

Structural, magnetic, electrical, and magnetotransport properties have been carried out on the Ag-added La0.67Ba0.33MnO3/(TiO2)0.035 (LBT) (abbreviated by LBT/Agx,) composites. Ag addition has little influence on the magnetization or Curie temperature (TC), but decreases the resistivity (ρ) and sharps the ρ peak evidently. The ρ in the ferromagnetic (FM) metallic regime is proportional to T2, reflecting that the conductive mechanism mainly arises from the electron–electron scattering. In the paramagnetic (PM) insulating region, the ρ data fit well to the self-trapped small polaron hopping model. The ρ–T curves for x=0.27 and 0.30 samples fit well with the phenomenological percolation approach, which is based on the phases segregation of ferromagnetic metallic clusters and paramagnetic insulating regions. These excellent agreements highlight the dominant intrinsic behavior of LBT. In addition, from the magnetotransport measurements, a large magnetoresistance (MR) ratio up to 41% was obtained at 280K, and 10kOe for x=0.27 sample. The good fits between the field dependence of MR and Brillouin function indicate that the MR behavior in the Ag-added LBT is induced by the spin-dependent hopping of the electrons among the spin clusters, and which is related to the increase and growth of the FM spin clusters.

The La2NiO4 metalloid conductive ceramics produced by conventional ceramic preparation technique were added into fine silver powders to form Ag/La2NiO4 composite contact materials. It is found by XRD that the phase structure of La2NiO4 ceramics did not change after arc erosion and exhibited a high chemical stability. The test results of model life and mechanical and physical properties show that the mass transfer and erosion is less and the performance of surface anti-erosion is more favorable for the contacts, resulting in the small resistivity and good mechanical properties. The Ag/La2NiO4 contacts exhibit an excellent performance compared with the Ag/CdO and Ag/SnO2 contact materials and very possible for the new type of contact materials as environmentally acceptable alternative to Ag/CdO.

We have prepared a series of polycrystalline manganites with the nominal compositions, La0.67Ba0.33Mn0.88Cr0.12O3/Agx (LBMCO/Agx) (x is the mole fraction) with x=0, 0.05, 0.1, 0.15, 0.2, 0.23, 0.27, 0.3, 0.35. The X-ray diffraction patterns show that the samples with x>0.05 are two-phase composites. The Ag addition in LBMCO improves the properties of grain surfaces/boundaries and reduces the resistivity of the composites. For x=0.30 sample, a minimum resistivity is obtained and a maximum room temperature magnetoresistance up to −54.5% was observed at 288K, 1T field. The room temperature TC and the reduced resistivity are responsible for the enhancement of room temperature MR.

With a small quantity of additive as the ameliorant,LaFe_(0.25)Ni_(0.75)O_3 ceramic was prepared by means of traditional solid-phase reaction.The study shows ameliorant leads to obvious improvement of the wettability and the accession mode play the important role.The wettability greatly affects the distribution of ceramic in the silver base and at the same time affects the service performance of the electrical contact materials.

The samples were prepared by doping Nb_2O_5 into the La_(0.67)Sr_(0.33)MnO_3 powder,which is synthesized by the sol-gel method.The XRD result indicates that all samples can be indexed based on the rhombohedral structure with single phase.The resistivities of the samples are influenced remarkably by Nb~(5+) addition.There is a maximum resistivity ρ for the sample with x=0.06(x is the molar ratio of the Nb ions to LSMO), which is higher than that for LSMO by five orders of magnitude.It is due to the enhancement of spin dependent and independent scattering and tunneling effects on the interfaces of grain boundaries and inside the grains.Enhancements of the low-field magnetoresistance(LFMR) and high-field magnetoresistance(HFMR) were observed.The maximum MR ratios at 77K with H=1T and H=0.1T are 42% and 25% for the 0.07molar ratio doped sample,which are 2 times and 1.7 times as large as that for LSMO,respectively.A MR effect up to 7% was also found for the sample with x=0.03 at room temperature.The spin dependent tunneling and scattering at the interfaces of grain boundaries are responsible for the LFMR while the HFMR originates from a noncollinear spin structure in the surface layer.

Two-phase composites LCBMO/Pdx were synthesized using the sol–gel technique followed by the solid-state reaction. Pd addition induces a remarkable decrease in resistivity, which is mainly related to the improvement of grain boundaries/surfaces caused by the segregation of Pd. The resistivity data for all samples follow the adiabatic small-polaron-hopping model at high temperature above the Curie temperature TC, while in the low temperature region, they are proportional to T2, reflecting that the electron–electron scattering mechanism is dominant in the ferromagnetic metallic state. In addition, Pd addition induces a large enhancement of room temperature magnetoresistance (MR). Especially for the x = 0.27 sample, an extra large magnetoresistance over 170% is obtained at 10 kOe and 289 K. This is the largest MR obtained at room temperature in all kinds of colossal magnetoresistance (CMR) materials. The good conductivity and polarizing effect of Pd are responsible for the enhancement of MR. The former leads to the decrease in resistivity and the latter induces a large number of spin clusters.

A series of La0.67(Ca0.65Ba0.35)0.33MnO3∕Pdx composites were synthesized using a sol-gel method followed by a conventional solid-state reaction route. The results show that the resistivity of the composites decreases dramatically with Pd addition, while the room-temperature magnetoresistance (MR) increases remarkably. A large MR of about 170% is obtained at room temperature and 1T applied magnetic field for x=0.27 sample. The large enhancement of the MR can be attributed to the decrease in resistivity caused by the good conductive metal Pd, which improves the disordered atomic structure and magnetic property on the grain surfaces/boundaries. In addition, the polarization of Pd atoms near the Mn ions on the grain surfaces/boundaries also plays a very important role on the enhancement of the MR, which induces a large number of spin clusters.

Using sodium dodecylsulfate solution (SDS) as the pore-forming agent and ZnO nanoparticles as the starting material, ZnO porous bulk solid was successfully prepared by a novel solvothermal hot press method. Furthermore, the effects of the addition of polyethylene glycol 400 (PEG-400) into the solvent were also investigated. It was found that, the pore diameter of the ZnO porous bulk solids largely decreased when PEG-400 was added into the solvent. Besides, the specific surface area and porosity also decrease correspondingly. On the other hand, the uniformity of the channel diameter of ZnO bulk porous nanosolids was greatly improved.

The effects of Ag addition in the composite (La0.7Sm0.3)(0.7)Sr0.3MnO3/Ag-x abbreviated as LSSMO/Ag-x has been studied. The results showed that Ag addition induces the decrease in resistivity (p) due to the improvement of grain boundaries resulted from the segregation of Ag on the grain surfaces. In addition, 27% molar ratio of Ag addition induces a large room temperature magnetoresistance (MR) ratio of 35%. The good agreement of experimental data with Brillouin function indicates that the MR behavior in this composite system accounts for the spin-dependent hopping of the electrons between the spin clusters.

Novel bulk ZnO porous nanosolids were prepared by a unique solvothermal hot-press method, using ZnO nanoparticles and several kinds of solvents as the starting materials. It was found from the experiments that ZnO nanoparticles underwent a 'self-assembly process' under some specific hydrothermal hot-press conditions. As a result, some 'nanoflowers' formed. The results showed that porous nanosolids with uniform pore diameters could be obtained when water distributed uniformly among the ZnO nanoparticles. On the contrary, if the uniformity of the distribution of water was poor, 'nanoflowers' would appear in the water-rich region. It was also found that the photoluminescence of ZnO porous nanosolids was affected by the self-assembly phenomenon. In addition, the results also showed that, both the volume and diameters of the pores could be adjusted by changing either the hot-press temperature, pressure or the kinds of solvents.