Phytoremediation potentiality of garlic roots for 2,4-dichlorophenol removal from aqueous solutions.

2,4-Dichlorophenol (2,4-DCP) is considered as an important pollutant because of its high toxicity and wide distribution in wastewaters. Innocuous remediation technologies have been studied for the removal of this pollutant. This study investigated the feasibility of using garlic roots as a plant system for the removal of 2,4-DCP. The optimal conditions for its removal were established based on orthogonal experiments (OA25 matrix). Significant factors that affect removal efficiency, arranged from high to low importance, include pH, reaction time, 2,4-DCP concentration, and H2O2 concentration. In addition, garlic roots could be re-used for as much as three consecutive cycles. The decrease in pH and the increase of Cl(-) ion content in the post-removal solutions indicated that 2,4-DCP dehalogenation occurred during transformation. Changes in the deposition pattern of lignin in roots exposed to 2,4-DCP suggested that several of the products deposited were lignin-type polymers. The acute toxicity test revealed that the post-removal solutions were less toxic than the parent solutions. Therefore, garlic roots have considerable potential to effectively and safely remove 2,4-DCP from wastewater.

Self-emulsifying drug delivery system and the applications in herbal drugs.

Herbal drugs have been used for thousands of years in the east and have had a recent resurgence in popularity among consumers in the west. However, most of herbal drug are poorly soluble and have hydrophobic properties and poor distribution, leading to reduced bioavailability and hence decreased treatment efficacy, requiring repeated administration or increased dose. In the past few decades, considerable attention has been focused on the development of self-emulsifying drug delivery system (SEDDS) for herbal drugs. SEDDS is isotropic and thermodynamically stable solutions consisting of oil, surfactant, co-surfactant and drug that can spontaneously form oil-in-water micro/nanoemulsion when mixed with water under gentle stirring. The formulation can be a viable alternative to classical formulations to take advantage of their lipophilic nature and to solve their problems of poor solubility, poor bioavailability, low oral absorption and instability. The mechanism of self-emulsification, solubility studies, construction of phase diagram, optimization and characterization of herbal drugs-loaded SEDDS formulation and in situ absorption evaluation of herbal drugs in rat intestine are presented in our article.

Contaminant removal from low-concentration polluted river water by the bio-rack wetlands.

The bio-rack is a new approach for treating low-concentration polluted river water in wetland systems. A comparative study of the efficiency of contaminant removal between four plant species in bio-rack wetlands and between a bio-rack system and control system was conducted on a small-scale (500 mm length x 400 mm width x 400 mm height) to evaluate the decontamination effects of four different wetland plants. There was generally a significant difference in the removal of total nitrogen (TN), ammonia nitrogen (NH3-N) and total phosphorus (TP), but no significant difference in the removal of permanganate index (COD(Mn)) between the bio-rack wetland and control system. Bio-rack wetland planted with Thalia dealbata had higher nutrient removal rates than wetlands planted with other species. Plant fine-root (root diameter < or = 3 mm) biomass rather than total plant biomass was related to nutrient removal efficiency. The study suggested that the nutrient removal rates are influenced by plant species, and high fine-root biomass is an important factor in selecting highly effective wetland plants for a bio-rack system. According to the mass balance, the TN and TP removal were in the range of 61.03-73.27 g/m2 and 4.14-5.20 g/m2 in four bio-rack wetlands during the whole operational period. The N and P removal by plant uptake constituted 34.9%-43.81% of the mass N removal and 62.05%-74.81% of the mass P removal. The study showed that the nitrification/denitrification process and plant uptake process are major removal pathways for TN, while plant uptake is an effective removal pathway for TP.

Microbiological characteristics of multi-media PRB reactor in the bioremediation of groundwater contaminated by petroleum hydrocarbons.

A multi-media bio-PRB reactor was designed to treat groundwater contaminated with petroleum hydrocarbons. After a 208-day bioremediation, combined with the total petroleum hydrocarbons content in the groundwater flowed through the reactor, microbiological characteristics of the PRB reactor including microbes immobilized and its dehydrogenase activity were investigated. TPH was significantly reduced by as much as 65% in the back of the second media layer, whereas in the third layer, the TPH content reached lower than 1 mg l⁻¹. For microbes immobilized on the media, the variations with depth in different media were significantly the same and the regularity was obvious in the forepart of the media, which increased with depth at first and then reduced gradually, while in the back-end, the microbes almost did not have any variations with depth but decreased with the distance. The dehydrogenase activity varied from 2.98 to 16.16 mg TF L⁻¹ h⁻¹ and its distribution illustrated a similar trend with numbers of microbial cell, therefore, the noticeable correlation was found between them.

[Effects of EGb761 on hippocamal synaptic plasticity of vascular dementia rats].

AIM: To investigate the effects of ginkgo biloba extract 761 (EGb761) on synaptic plasticity in hippocampus of vascular dementia (VD) rats. METHODS: The escape latency (EL) of Morris water maze (MWM) task was measured at different time points (4 W, 8 W and 16 W), and the population spikes (PS) of granule cell layer in the dentate gyrus were induced by single pulse stimulation to perfo rate path fibers before and after high frequency stimulation (HFS) in vivo. RESULTS: MWM test showed that the escape latency (EL) of VD model group were highly longer than that of the sham-operated group, while the EL of EGb761-treated group was significantly shorter than that of model group, but still longer than that of the sham-operated group. The incidence rates of LTP induction in 1 m, 2 m and 4 m subgroups of model group were significantly lower than that of sham-operated group and EGb761-treated group at different time point. The relative amplitudes of PS after HFS in 1 m, 2 m and 4 m subgroups of model group were obviously reduced compared with that of the corresponding subgroups of sham-operated group and EGb761-treated group. There was no obvious significance in the peak latency of PS between different subgroups and different LTP-tested time point. CONCLUSION: VD model rats had apparent and long-lasting dysfunction of learning and memory, EGb761 could accelerate the recovery of the pathological synaptic plasticity. This suggested that EGb761 played an important and improving role on learning and memory dysfunction of VD.