In vitro antibacterial, antioxidant, total phenolic contents and anti-HIV-1 reverse transcriptase activities of extracts of seven Phyllanthus sp

AbstractPhyllanthus species has long been used in folk medicine in many countries as antimicrobials and/or antioxidants. Eighty percent methanol extracts obtained from seven Phyllanthus sp. were evaluated for antibacterial activity using the broth micro-dilution assay, anti-HIV-1 reverse transcriptase (RT) activity using the HIV-RT assay, antiradical scavenging effects and phenolic contents using the DPPH assay and Folin–Ciocalteau colorimetric method, respectively. Best antibacterial activity as indicated by the minimum inhibitory concentration (MIC) values was obtained by Phyllanthus amarus against Staphylococcus aureus (Gram-positive) with a MIC value of 17.7μg/ml. Phyllanthus myrtifolius and Phyllanthus urinaria inhibited growth of Pseudomonas stutzeri (Gram-negative) with MIC values of 78μg/ml and 117μg/ml, respectively. A strong inhibition of HIV-RT was obtained by Phyllanthus pulcher (IC50 5.9μg/ml) followed by P. urinaria and P. myrtifolius (IC50 of 10.4 and 12.7μg/ml, respectively). A remarkable DPPH scavenging effect was observed with P. myrtifolius, Phyllanthus reticulatus and P. urinaria (IC50 of 10.2, 10.8 and 17.4μg/ml, respectively). Highest total phenolic contents were recorded for P. myrtifolius and P. urinaria (207 and 205mg/GAE/g respectively). With the exception of P. amarus, Phyllantus debilis and P. pulcher, total phenolic contents correlated with DPPH radical scavenging activity. Our findings support the uses of the Phyllanthus species in traditional medicine. The interesting biological activities obtained by P. myrtifolius, P. urinaria and P. pulcher need to be further investigated to isolate active agents and to study their mechanism of action

Finite element analysis of tibia with osteogenesis imperfecta: the influence of considering cancellous bone in model reconstruction

The paper aims to develop the finite element (FE) models of tibia with Osteogenesis Imperfecta (OI) based on a patient-specific computed tomography (CT)-images. Two types of FE model have been developed. The first model was set the tibia bone as a single solid model whereas the second model consists of cortical bone and cancellous bone. The developed FE models were used for FE analysis using Voxelcon under various loadings, and then the results of the different models were compared. It was found that the single model yields relatively in agreement to piecewise model, with percentage different of below than 2% for all loading conditions. It seems that the reconstructed FE model considering the cancellous bone did not give significant effect compared to the solid model that neglecting the microstructure of cancellous bone. Hence, we can conclude that the single solid FE model with OI has predicted well, at least for the present boundary conditions, although the cancellous bone was neglected in the model reconstruction

Chemosystematic studies of the tribe Mimoseae (Mimosoideae)

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN014301 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Effect of loop diameter on the performance of MKR-based dual-wavelength erbium-doped fiber laser

A dual-wavelength Erbium-doped fiber laser (EDFL) is demonstrated using a 1.5-m long EDF with a microfiber knot resonator (MKR) structure at the output end. The MKR is fabricated by heating and stretching a 3-cm long piece of EDF to form a microfiber, which is then manipulated to create a knot. The performance of the EDFL is investigated for two different MKR loop diameters. At a loop diameter of 4 mm, dual-wavelength laser is obtained at 1532.4 and 1556.0 nm with peak powers of −7.5 and −7.1 dBm and the corresponding optical signal-to-noise ratios of 22 and 32 dB, respectively. As the MKR diameter is reduced to 2 mm, the operating wavelength of laser shifts to a shorter wavelength, especially for the second lasing with a significant drop in output power due to the bending loss, which is more pronounced at smaller loop diameter. The slope efficiency of the EDFL drops from 0.55 to 0.09% as the MKR diameter decreases from 4 to 2 mm

O-band bismuth-doped fiber amplifier with double-pass configuration

A Bismuth-doped fiber amplifier (BDFA) in a double-pass configuration is proposed and demonstrated. The BDFA consists of a Bismuth-doped phosphogermanosilicate (BiPGeSiO2) fiber pumped by a Titanium-Sapphire source at 810 nm. The BDFA has an amplified spontaneous emission (ASE) spectrum with a 3-dB bandwidth from 1220 to 1490 nm. The maximum gain of the proposed BDFA is 2.0 dB at an input signal wavelength of 1340 nm and is a gain enhancement of 100% over a similarly configured single-pass BDFA. The proposed BDFA has a higher gain enhancement of 1.7 dB at low input signal powers but decreases to as low as 0.5 dB as the input signal power increases

Antioxidant and antibacterial activities of flavonoids and curcuminoids from Zingiber spectabile Griff

The antioxidant potential of spectaflavoside A (1) along with kaempferol and its four acetylrhamnosides(2e6), demethoxycurcumin (7) and curcumin (8), isolated from the rhizomes of Zingiber spectabile was evaluated using three different assays; 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, ferric reducing antioxidant power assay (FRAP) and b-carotene bleaching assay, while their antibacterial activities against eight different food-borne bacteria; Escherichia coli, Klebsiella pneumoniae, Proteus vulgaris, Salmonella typhimurium, Vibrio parahaemolyticus, Bacillus cereus, Bacillus licheniformis and Staphylococcus aureus were determined using broth microdilution assay. The highest antioxidant activity in all assays was demonstrated by kaempferol (6), with more that 89% of activity. This was followed by curcumin (8) and demethoxycurcumin (7). These two curcuminoids were found to have the potential in extending the shelf-life of different food products as compared with other tested compounds due to the higher antioxidant activities that are ranging from 56.27% in FRAP assay to 77.27% in b-carotene bleaching assay, and minimum inhibitory concentrations against six food-borne bacteria are ranged from 62.50 mg/mL to 500 mg/mL. Hence, this would suggest that the rhizomes of Z. spectabile may be a promising source of natural preservative in the food industry

Brillouin-raman multi-wavelength laser comb generation based on BI-EDF by using dual-wavelength in dispersion compensating fiber

A multi-wavelength Brillouin fiber laser (BFL) is demonstrated by using dual-wavelength fiber in a 7.7km dispersion compensating fiber (DCF) that is incorporated in a 49 cm Bismuth erbium-doped fiber laser. The BFL operates in C-band, which is shifted by 0.08nm and amplified by a Raman pump (RP). The threshold power for BP pumps and the Raman pump is achieved at 7dBm and around 35mW, respectively. The exclusive and practical benefits of using reduced high nonlinear Bismuth-erbium doped fiber (Bi-EDF) in implementing a four-wave mixing (FWM) method for multi-wavelengths Brillouin fiber laser (BFL) applications are experimentally demonstrated. Coupled interactions of Brillouin, Raman, and FWM scattering explain the unique feature of proposed configuration

High power and compact switchable bismuth based multiwavelength fiber laser

A compact switchable multiwavelength fibre laser (SWFL) is proposed and demonstrated using a bismuth based erbium doped fibre amplifier (Bi-EDFA) and a Sagnac loop mirror (SLM) in a ring cavity. The proposed compact SWFL can generate up to 6 switchable wavelengths with an average peak power of 11 dBm and also shows good stability over time with a high side mode signal ratio (SMSR) of 40 dB that negates minor fluctuations in the laser output. The Bi-EDF based gain medium gives the SWFL a large usable bandwidth of up to 80 nm, and it is expected that this will allow the SWFL to be used as a tunable laser source for high power applications to meet increasing demand

Highly efficient and high output power of erbium doped fiber laser in a linear cavity configuration

A simple Erbium Doped Fiber Laser (EDFL) in linear cavity configuration is reported. The cavity design is based on an FBG as a back reflector, and a loop back optical circulator with an output coupler as the front reflector. Different coupling ratios of the coupler are tested and 50 : 50 provides the highest coupling output power of 22.06 dBm (160.7 mW). The pump power conversion efficiency is about 95% when pumping with two pump lasers at 1460 and 1490 nm with combined pumping power of 545 mW. The laser output has a measured linewidth of 0.0179 nm

Nanoindentation measurement on interstitial and osteon of bone with osteogenesis imperfecta-type III

"Osteogenesis imperfecta (OI) is one of the genetic disorder which was characterized by bone fragility. Previous studies reported that there are several mechanical properties has been used to investigate the strength of OI bone. However, little data is yet available to describe bone material properties in individuals with this disorder for type III alone. Therefore, the aim of this study is to investigate the mechanical properties in individual with OI bone type III at interstitial and osteon. Bone tissue reduced modulus and hardness were measured by nanoindentation in three specimens with total 40 indents. These properties were compared between osteogenesis imperfecta types III for interstitial and osteonal microstructural regions. Individual with osteogenesis imperfecta type III had higher hardness and reduced modulus at interstitial rather than osteonal bone regions. Overall, the mean and standard deviation of hardness is 0.6 ± 0.11 GPa, while 0.44± 0.06 GPa for osteon. The current study presents the dataset describing the bone material properties in individual with Osteogenesis Imperfecta Type III. Results indicate that intrinsic bone tissues properties were affected by phenotype. Knowledge on the mechanical properties of severity osteogenesis imperfecta may help to assist the model and prevent the fracture risk for those having this disorder.