Ternary Solid Nano Organic/Inorganic Composite of Lanthanum with Acetic Acid and Curcumin/ Hydroxyapatite and Its Antibacterial Activity

Ternary solid complex was synthesized via hybridization of curcumin（Cur）, hydroxyapatite（HAP）, lanthanum（La） and acetic acid（HAc）. The nano-scale hybrid composite of La-Cur/HAP was directly prepared by the wet method. The morphologies and structures of the composite were characterized by scanning electron microscopy （SEM）, infrared（IR） spectroscopy, X-ray diffraction（XRD）, transmission electron microscopy（TEM） and energy dispersive X-ray spectroscopy. The antibacterial activities were tested by methods of minimum inhibitory concentration （MIC） and minimum bactericidal concentration（MBC）. The results show that the size of the La-Cur/HAP composite is less than 100 nm, and the composite exhibits strong bacteriostatic activity against Escherichia coli（E, colt） and Staphylococcus aureus（S, aureus） at low concentrations（in the range of 26-92μg/mL）. The composite can exhibit both of the bacteria and shows higher antibacterial activity against S. aureus than against E. colt. At the same time, La-Cur/HAP shows stronger antibacterial efficiency than ampicillin/HAP.     

Evaluation of various biological activities of natural compounds by TLC/HPTLC

Abstract

Over the last years, thin layer chromatography (TLC) has become an increasingly important tool in the analysis of natural compounds, being used not only as a simple method of separation, identification, and quantitative determination of natural constituents, but also as a method for evaluating the potential applications of the separated compounds, different bioassays being compatible with TLC. This is due to the TLC advantages, of which could be mentioned: the possibility to simply, quickly, and flexibly analyze many samples in parallel, without the need for special steps of sample purification, obtaining visual results, and the possibility of multiple detections, all of these being achieved at very low costs. Considering these, the aim of this study is to give an overview on the application of TLC in evaluation of different biological activities of natural compounds, focusing on antioxidant, enzymatic, antimicrobial, and hormonal activities.     

An efficient preparation and characterization of 1-(2-ethoxy-2-oxoethyl)imidazolium based ionic liquids derivatives as potential bioactive agents

A set of new 1-(2-ethoxy-2-oxoethyl)imidazolium-based ionic liquids (1–16) have been prepared via the alkylation reaction of ethyl 2-(1H-imidazol-1-yl)acetate with various type of substituted alkyl halides using a microwave irradiation reaction in yields above 90%. The chemical structures of the manufactured ILs (1–16) were analyzed by mass and NMR spectroscopy. The newly prepared ILs were examined for their in vitro anti-microbial activities towards different types of Gram (+) and Gram (−) bacteria, and also for their antifungal activities. The preliminary tests showed that most of the resultant ILs presented modest activities towards S. aureus and B. subtilis with IZ values ranging between 10 and 14 mm, while the E. coli activities was in the range of 16 and 20 mm. However, ILs (1–16) displayed poor activities against the C. albicans.     

Synthesis of montmorillonite-based tris(2-ethylamine)-Schiff-base composites with remarkable antibacterial activity

A range of heterogeneous, inexpensive and benign Schiff bases-montmorillonite composites were synthesized and screened for their antibacterial activity against common microbial pathogens. Sodium montmorillonite (Na-MMT) clay was modified with tris(2-ethylamine) in the presence of dilute HCl to yield a quaternary salt of tris(2-ethylamine) modified clay. The Schiff bases were then fabricated from the reaction of the modified montmorillonite using different aldehydes. The structures of the obtained compounds were confirmed by Fourier transformer Infrared (FT-IR), X-ray diffraction (XRD), and thermal gravimetric analysis (TGA). All the obtained composite materials were screened for their antibacterial activities against the multi-drug resistant (MDR) strains. It was reasoned that the modified MMT-based composites has the ability to absorb the different micro-organisms onto the surface, and accordingly act as an effective antibacterial agent. All the composites showed significant antibacterial activity between 2.5 and 20 mg/mL against the MDR bacterial strains. The benzyl-based/modified MMT and the tertiary amino-based/modified MMT was found to be the most effective antibacterial agent.     

Dye removal,antibacterial properties,and morphological behavior of hydroxyapatite doped with Pd ions

Hydroxyapatite (HAP) containing different contents of palladium (Pd) ions were synthesized using the co-precipitation method. The structural and morphological properties of the as-synthesized compositions were investigated using XRD and FESEM. The c/a increased from 0.728 to 0.733 with the lowest and highest contributions of Pd(II), respectively. Furthermore, the morphological features were investigated using FESEM. It was illustrated that Pd-HAP was formed as agglomerated as rod shapes with dimensions in the range of 63.4–110.3 nm for no Pd additions, and the size was reduced reaching 43.4–70.5 nm for the highest Pd contribution. Besides, the maximum height of the roughness (R_t) grew from 183.6 up to 236.5 nm for the lowest and highest Pd(II). Besides, the obtained specific surface area was around 28.3, 42.0, and 63.4 m²/g for 0.0Pd-HAP, 0.6Pd-HAP, and 1.0Pd-HAP, respectively. The antibacterial activity was examined against both Escherichia coli (E-coli) and Staphylococcus aureus (S. aureus), and it obvious that the activity was enhanced upon Pd content. The inhibition zone was increased from no sensitivity reaching 4.3 ± 0.9 and 4.5 ± 0.8 mm for no Pd and the highest one, respectively. The removal efficiency of dyes was examined for methylene blue (MB) and it was shown that after 120 min of irradiation, the removal efficiency reached around 86.4% for the highest contribution of Pd. The pseudo-first-order constant (K_app) increased from 0.0032 to 0.0179 min⁻¹. The recyclability of Pd-HAP denoted that removal efficiency decreased to 5.65, 8.14, 6.24, 8.76, and 10.2% for different contents of Pd(II) after 6 cycles.     

Phytochemical profiling and antimicrobial activity of ginger (Zingiber officinale) essential oils against important phytopathogens

The objectives of this study were to profile ginger essential oils (EOs) phytochemical constituents and antimicrobial activity against important phytopathogens. Ginger EOs was extracted using a modified Clevenger-type apparatus by hydro-distillation then followed by GCMS and headspace analysis of its phytochemical constituents. The phytoconstituents identified were monoterpenes and sesquiterpene hydrocarbons. Food poisoned and disc diffusion techniques were applied to determine the percentage inhibition of fungal mycelial and bacterial growth respectively. The EOs produced mycelial growth inhibition in all the test fungal pathogens after five days of incubation. The MIC and MFC of the EOs on the tested fungi were in the range of 1 μl/ml and 5–6 μl/ml, respectively. The bacterial growth of all the tested isolates was also affected by EOs at 100–500 µl/ml, from weak to strong antibacterial activity. The EOs affected the Xanthomonas oryzae pv. oryzae-strain A isolate most at a higher concentration of 400–500 μl/ml with mean inhibition of 20.66 mm and 22.66 mm respectively, which are found to be effective. The MIC values on the bacterial pathogens were at100 μl/ml. The inhibition zone of positive control (streptomycin) at 15 µg/disc was 25.00 mm and appeared to be efficient. Metabolomics analysis to concurrently quantify variability among multiple compounds in the data sets and identify such compounds responsible for the X. oryzae pv. oryzae-strain-A inhibition were determined. The cross-validated PLS model has shown a strong correlation between ginger EOs and bioactivity. The action of ginger EOs on the cell structure was fully identified using SEM by observing the changes in morphology and integrity of X. oryzae pv. oryzae-strain-A cells. The DMSO treatment (control) showed a normal rod shape cell, while treatment with the ginger EOs showed irregular shape with sunken surfaces, and treatment with antibiotics display abnormal growth of the cells. These findings can, therefore, propose that the ginger EOs could be used as a new antimicrobial agent in suppressing the growth of phytopathogens and as possible new alternatives to synthetic fungicides and bactericides.     

测量光纤外腔Fabry-Perot干涉仪的白光干涉术

提出了一种基于白光干涉术测量低锐度光纤外腔Fabry Perot干涉仪（EFPI）的方法用宽带光源注入F P腔,在接收端用一高锐度的可调谐光纤F P滤波器对EFPI的反射光谱进行扫描,获得了周期性变化的光谱输出为了测量出EFPI的腔长,对光谱信号进行傅里叶变换,得到光谱的周期,由此求出EFPI的绝对腔长证明了用低锐度EFPI的测量准确度由腔长决定F P腔越长,测量准确度越高在腔长分别是200 μm,400 μm和600 μm时,测量的腔长与实际腔长相同.     

温度/应变/扭曲三参量同时测量低成本传感系统

提出了一种利用布喇格光纤光栅反射光作信号源、高频CO2激光脉冲写入的长周期光纤光栅和超周期光纤光栅作传感器实现温度、应变和扭曲同时测量的全光栅型低成本强度解调传感方案.文中利用长周期光纤光栅边缘滤波效应实现了温度、应变和扭曲传感信号的实时解调.实验结果表明,其温度和应变的测量灵敏度分别为－0.211 dB/℃和－0.012 dB/10με;而扭曲率的测量灵敏度为0.4394 dB/(rad·m－1),是该法写入普通LPFG的4倍以上.     

新型三段高性能的长波段掺铒光纤超荧光光源的研究

提出了一种第一段无泵浦、第二段前向泵浦和第三段后向泵浦的三段级联掺铒光纤超荧光光纤光源的新结构.数值分析了泵浦光波长、铒光纤长度以及泵浦比例对新结构性能的影响.结果表明可以找到一组适合制作成本低廉、输出功率高、谱平坦的长波段掺铒光纤超荧光光源.