Application of Graphene and Carbon Nanotubes on Carbon Felt Electrodes for the Electro-Fenton System.

The electro-Fenton system has the ability to degrade wastewater and has received attention from many researchers. Currently, the core development objective is to effectively increase the degraded wastewater decolorization efficiency in the system. In this study, to improve the electro-Fenton system reaction rate and overall electrical properties, we used polyvinylidene difluoride to fix carbon nanotubes (CNTs) and graphene onto the system cathode (carbon felt electrode), which was then used to process Reactive Black 5 wastewater. Furthermore, we (1) used scanning electron microscopy to observe the structural changes in the electrode surface after modification; (2) used the Tafel curve to determine the electrode corrosion voltage and corrosion rate; and (3) analyzed the azo-dye decolorization level. The results showed that the maximum system decolorization rates of the CNT- and graphene-modified carbon felt electrodes were 55.3% and 70.1%, respectively. These rates were, respectively, 1.2 and 1.5 times higher than that of the unmodified carbon felt electrode, implying that we successfully improved the cathode characteristics. The modified electrode exhibited an improved conductivity and corrosion resistance, which, in turn, improved the system decolorization efficiency. This significantly increased the electro-Fenton system overall efficacy, making it valuable for future applications.

[Concentrations and pollution assessment of mercury in farmland soil of Xinqiao Mining Area of Tongling, Anhui, China.] / é“œé™µæ–°æ¡¥çŸ¿åŒºå‘¨è¾¹å†œç”°åœŸå£¤æ±žå«é‡åˆ†å¸ƒç‰¹å¾åŠå ¶æ±¡æŸ“è¯„ä»·.

To investigate the effects of mining activities on mercury (Hg) enrichment in farmland soil, soil samples were collected from four villages (Xinjian Village, Yehu Village, Xinhu Village and Hucheng Village) in the vicinity of Xinqiao Mining Area, Tongling. Hg concentration was measured by atomic fluorescence spectrophotometer. The geo-accumulation index was used to evaluate the Hg pollution level of the soils. The results showed that average concentration of total Hg in farmland soil was (0.137±0.078) mg·kg-1, which exceeded the background value of soil Hg in Tongling area. The average concentration of Hg in four villages followed the order of Xinjian Village (0.221 mg·kg-1)>Xinhu Village (0.118 mg·kg-1)>Yehu Village(0.115 mg·kg-1)>Hucheng Village (0.096 mg·kg-1). Moreover, the average Hg concentration of different forms in Xinjian Village followed the order of residue (0.036 mg·kg-1) > alkali soluble (0.031 mg·kg-1) > hydrogen peroxide soluble (0.022 mg·kg-1)> acid soluble (0.020 mg·kg-1)> water soluble (0.012 mg·kg-1). The distance from the mining area was the main factor affecting the distribution of soil Hg concentration in farmlands. The contaminated Xinqiao River, to some degree, had exa-cerbated soil Hg pollution. Soil organic matter affected the accumulation and transformation of total Hg and hydrogen peroxide Hg in the farmlands. The order of the geo-accumulation index followed as Xinjian Village(1.559) >Xinhu Village(0.654) >Yehu Village(0.616) >Hucheng Village(0.356). The pollution level of farmland soil in Xinjian Village belonged to middle level of Hg pollution,which deserved more attention.

The manufacturing of a metallic nano-cluster at a tip apex for field-sensitive microscopy applications.

Using a conductive atomic force microscopic setup, a metallic nano-cluster at a tip apex was successfully manufactured by an electrochemical redox process from an anodic aluminum oxide template. The diameter of the metallic nano-clusters ranged from 15 nm to 200 nm. The diameters of the nano-clusters could be well-controlled by adjusting the pore size of the templates. The formation of a variety of metallic nano-clusters at the tip apex was accomplished by preparing the electrolyte solution from different metallic salts. The formation mechanism for the nano-cluster is outlined and discussed. Moreover, we were able to enhance the performance of the nano-cluster tips for field-sensitive scanning probe microscopy, including electrostatic force microscopy and scanning Kelvin probe microscopy by laser annealing. Our experimental results indicated that for applications in field-sensitive scanning probe microscopy the stray field effect was significantly suppressed by the nano-cluster tip and hence the spatial resolution was improved.

[Management of corneo-conjunctival malignant melanoma with "no touch technique" surgical excision and corneoscleral lamellar keratoplasty].

OBJECTIVE: To study the management of "no touch technique" surgical excision and corneoscleral lamellar keratoplasty in the treatment of corneo-conjunctival malignant melanoma. METHODS: Surgical excision for corneo-conjunctival malignant melanoma in six cases, from October 1989 to January 2004 in Zhongshan Ophthalmic Center, were performed. The entire tumors were removed in one piece without touching the tumor (no touch technique). The incision was outlined 4-6 mm outside the pigmented conjunctival mass, and 2 mm outside the corneal component. Dissecting deep enough without any tumor cell left to yield a tumor-free bed. After surgical incision, the host eyeball defect was covered with partial or total corneoscleral lamellar graft from fresh donor, and the conjunctiva defect was covered with or without amniotic membrane transplantation. All the patients were followed up to 6 months. RESULTS: The tumors in the remaining conjunctival margins were completely removed by local dissection combined with cryotherapy in the six cases. Three cases were treated with partial corneoscleral lamellar keratoplasty, two cases with total corneoscleral lamellar keratoplasty and one case with total corneoscleral lamellar keratoplasty plus amniotic membrane transplantation. All cases were subsequently treated with 0.01% thiotepa eyedrops and supplemental dacarbazine chemotherapy. At the average 43.5 months follow-up time (14.6 years to 6 months), no evidences of local recurrence of malignant melanoma or distant metastasis were observed. CONCLUSION: The clinical study suggests that using surgical excision of "no touch technique" to remove tumor in whole piece with corneoscleral lamellar keratoplasty is effective in the treatment of corneo-conjunctival malignant melanoma.

Effect of recombinant epidermal growth factor on ocular surface re-epithelization following amniotic membrane transplantation in patients with pterygium excision.

OBJECTIVE: To observe the effect of recombinant human epidermal growth factor (rhEGF) on ocular surface re-epithelization and the efficacy of amniotic membrane transplantation in patients with pterygium. METHODS: Amniotic membrane transplantation was performed on 40 eyes of 36 patients with pterygium after removal of pterygium. All the eyes were randomly divided into 2 groups: 20 eyes received rhEGF ophthalmic solution and the other 20 drug vehicle. The healing rates of the corneal and conjunctival epithelium were observed respectively. Follow-up study lasting for 3 to 12 months was conducted in all the cases postoperatively. RESULTS: The healing rate of both the corneal and conjunctival epithelium in rhEGF-treated group (74.983+/-18.998 micrometer/h and 36.584+/-7.888 micrometer/h respectively) was significantly faster than the control (59.372+/-17.197 +/-m/h and 29.18+/-5.450 micrometer/h respectively, P<0.01 for both comparisons). Follow-up witnessed no recurrence of the disease. CONCLUSIONS: rhEGF effectively promotes the healing of ocular surface epithelium defect, and amniotic membrane transplantation is a good surgical procedure for treating pterygium.