Search

Melastoma dodecandrum Lour. (MDL) is component used in traditional Chinese medicine that is widely distributed throughout southern China. MDL has been long utilized in clinical treatment for various conditions, such as inflammation. However, the toxicity and underlying anti-inflammatory mechanism of MDL remain to be elucidated. In the present study, Sprague-Dawley rats received intragastric administration of MDL for 2 months, and the toxicity of MDL was investigated. The rats were treated with lipopolysaccharide (LPS) for 8 h to determine the potential anti-inflammatory mechanism of MDL. The results demonstrated that MDL alone did not affect the expression levels of factors associated with inflammation (IL-1β, IL-6 and TNF-α) and oxidative stress [malondialdehyde (MDA), superoxide dismutase (SOD) and nitric oxide (NO)] in the rat serum and exerted no effects on rat liver and kidneys. By contrast, MDL attenuated LPS-induced inflammation and oxidative stress by regulating specific cytokines, such as IL-1β, IL-6, TNF-α, MDA, SOD and NO in the rat serum and alleviated LPS-induced liver and kidney damage. Additionally, compared with the LPS group, MDL inhibited CD4(+) T cell differentiation into Th1 and Th17 cells and enhanced CD4(+) T cell differentiation into Th2 and Treg cells. MDL also suppressed reactive oxygen species (ROS) production and mitochondrial apoptosis by modulating mitochondrial apoptosis-related proteins in spleen CD4(+) T cells. In conclusion, the results of the present study demonstrated the non-toxic nature of MDL and revealed that it alleviated LPS-induced inflammation and oxidative stress by regulating differentiation and ROS production in CD4(+) T cells.

The study was conducted to determine the antibiotic resistance and virulence factors profile of Escherichia coli isolated from chicken faeces sample. Differential and selective media were used to isolate a total of 164 E. coli strains from 180 faeces samples at different chicken farm in east China. These strains were tested against 15 antibiotics using the agar disc diffusion. The isolates showed high resistance rates to sulfamethoxazole (91.5%), nalidixic acid (86%), tetracycline (85.4%), streptomycin (80.5%), ampicillin (79.9%), Trimethoprim-sulfamethoxazole (74.4%), Enrofloxacin (67.1%), Ciprofloxacin (56.7%), Norfloxacin (54.9%) and Chloramphenicol (51.2%). Rates of resistance to Amoxicillin/clavulanic acid, Gentamicin and Florfenicol were moderate (36, 37.8 and 14.6%), while low rates were recorded for Amikacin (9.2%) and Cefalexin (5.5%). Among the 164 isolates, 36 (23.7%) were haemolytic, 42 (27.6%) were hydrophobic, 132 (86.8%) were serum resistant and only four were positive for protease. Eleven virulence-associated genes, including iucA, tsh, Iss, fimH, sitA, hlyF, iron, traT,cdtB, ibeA, and cvaC, were screened for via polymerase chain reaction (PCR) amplification. The fimH gene was the most prevalent with a detection rate of 86.6%, followed by traT (58.5%), iron (29.3%), and Iss (25%) in these avian isolates. Key words: Escherichia coli, antimicrobial resistance, virulence, chickens.

The accurate refractive indices in visible range and their Sellmeier equations have been obtained for a series of LiNbO3: Mg (5 mol%) crystals with Ti or Nd doping. The phase matching angle for 1.064μm calculated by Sellmeier equation gives good agreement with experimental value. The TiO2 and Nd2O3 doping cause the decrease of the birefringence and the increase of the phase matching angle. The conversion efficiency is enhanced by TiO2 doping. The second harmonic generator with conversion efficiency of more than 44% has been achieved at room temperature with phase matching angle close to 90°.

The transformation from stage-2 to stage-1 in HClO4-graphite intercalation compounds is studied by in-situ Raman scattering. The results show the coexistence of well-ordered regions of both stages during the stage transition. The resonant enhancement of Raman scattering has been found in stage-1 and stage-2 HClO4-GICs.

The absorption spectra, photoconductivities and photovoltaic currents of LiNbO3:Fe crystals with different Mg doping levels and Li/Nb ratios in the oxidized state have been investigated at room temperature. The Fe2+ ions in LiNbO3:Mg:Fe with Mg content above a critical value are more easily oxidized than in crystals with Mg content below a critical value. The photoconductivity of LiNbO3:Mg:Fe crystals with Mg content above a critical value is one order of magnitude higher than those with Mg content below a critical value, however, the photovoltaic current of the former is one order of magnitude lower than the latter. The differences are postulated to be due to different sites of Fe in these two classes of crystals.

The TGS-TGFB system and its ferroelectric phase transition were studied by Raman spectroscopy, dielectric measurements and x-ray diffraction. The results showed that the substitution of H2BeF4 for H2SO4 causes the unit cell to contract and the contraction results in an increase of Tc . The order-disorder character of the ferroelectric phase transition in TGS is not influenced by the substitution. A broadening of the lowest A(TO) line in this system was observed near Tc . The maximum of the halfwidth is located about 2–4°C below Tc . This phenomenon may be related to the suppression effect of the dipole electric field on the fluctuations of spontaneous polarization.

The glass transition, structural relaxation and crystallization were observed in the crystallization processes of amorphous LiNbO3. There are two metastable amorphous states below the crystallization temperature. Structural and grain size changes were investigated by means of Raman scattering spectra and scanning electron microscopy.

The X-band electron paramagnetic resonance of eight LiNbO 3 : Fe crystals with different Mg doping levels and Li Nb ratios was studied at room temperature. The EPR spectra obtained fall into two classes with quite different spin-Hamiltonian parameters. The critical Mg content which distinguishes the two classes decreases (increases) with increasing (decreasing) Li Nb ratio. The sites occupied by the Fe ions in the two classes of crystals are postulated to be different. The spin-Hamiltonian parameters of Fe 3+ in Li-rich LiNbO 3 : Mg(5 mol%): Fe(0.05 wt%) crystals were found to be: g | = 2.025, g ⊥ = 1.910, B 0 2 = 0.266 × 10 −1 cm −1 , B 0 4 = 0.551 × 10 −5 cm −1 , B 3 4 = 0.326 × 10 −3 cm −1 , and those in LiNbO 3 : g | = 1.971, g ⊥ = 1.940, B 0 2 = 0.546 × 10 −1 cm −1 , B 0 4 = 0.290 × 10 −4 cm −1 , B 3 4 = 0.1

The influence of Nd:MgO:LiNbO3 composition on the optical quality and resistance to photorefraction has been studied. Nd:MgO:LiNbO3 (1 mol% Nd2 O3, 7.5 mol% MgO) crystal has been found to have enhanced resitance to photore- fraction, lower phase matching temperature and good optical quality. This crystal is promising material for self-frequency-doubled and self-Q-switched laser devices.

With relation to photorefraction, it has been found that higher light irradiation intensities can be withstood by Li-rich LiNbO3:Mg (5 mol%) than by the congruent LiNbO3:Mg (5 mol%). The photoconductivity of the former is an order of magnitude larger than that of the latter. Doping with 0.1 wt% Fe in Li-rich LiNbO3:Mg (5 mol%) does not distinctively alter its ability to resist photorefraction. The photovoltaic currents of Li-rich LN:Mg:Fe and Li-rich LN:Mg are nearly equal and are two orders of magnitude smaller than that of LN:Fe. The photoconductivity of Li-rich LN:Mg:Fe is an order of magnitude smaller than that of Li-rich LN:Mg and is much larger than that of LN:Fe.