Tribological Investigations on Tool Surfaces for Temperature-Supported Forming of Magnesium AZ31 Sheets.

Aiming to decrease friction coefficient ( µ ) during the forming of magnesium alloy sheets, nine (9) tools with different hole geometries in their surface (flat, elliptical, and circular) were manufactured from steel Boehler W400 VMR (as known as DIN 1.2343). Tribological investigations were accomplished on a strip drawing machine at 288 °C without lubricants. When compared with a standard tool (surface flat), on average, tools with circular geometries in their surface showed the smallest friction coefficient, while tools with elliptical geometries shown higher. The friction coefficient also was confronted with the ratio between area occupied by holes in the surface of the tool and the total tool surface (i.e., factor f (%)), hole diameter (Ø), and the distance between circle centers (d(c,c)). Principal Component Analysis (PCA) complemented the experimental approach. In summary, both approaches (experimental and theoretical) indicated that the manufactured tool with circular geometries on its surface presented lower friction coefficient values on the forming processes of the magnesium AZ31 sheets.

Transoral laser microsurgery for carcinoma in situ of the glottic larynx. A retrospective follow-up study.

BACKGROUND: To investigate long-term results of transoral CO2 laser microresection (TLM) in glottic carcinoma in situ (CIS). METHODS: A retrospective study of 34 patients with glottic CIS treated initially with TLM between 1986 and 2004. Median post-operative follow-up time was 62 months. RESULTS: Three- and 5-year local control rates were 97 and 93%, respectively. Four patients developed local recurrence (rTis, rTis, rT1, rT4) that could be salvaged by repeated TLM in all cases. Neither adjuvant radiotherapy nor open partial or total laryngectomy was performed. There was no tumour-related death in this series. CONCLUSION: TLM can be considered as an effective method in the treatment of glottic CIS not only for the primary therapy, but also in cases of local recurrence.

Probing lactate metabolism variations in large-scale bioreactors.

Lactate metabolism variations are frequently encountered in mammalian cell culture processes, especially during process scale-up. In this study, we took a multipronged approach to investigate the impact of pH, pCO2 , osmolality, base addition, and mixing conditions on the observed lactate variations in a Chinese Hamster Ovary (CHO) fed-batch process at 2,000 L scale. Two cultivating methods, CO2 -controlled and pH-controlled, were used to decouple the individual and synergistic effects from those factors. The individual effects from pH, pCO2 , and osmolality on lactate consumption/reproduction in the stationary phase were insignificant in the ranges studied though the initial lactate production rates varied. In contrast, lactate metabolism was found to be impacted by an interaction between mixing conditions and CO2 accumulation. High CO2 accumulation and poor mixing led to lactate reproduction, whereas either low CO2 or improved mixing were sufficient to result in lactate consumption. Base addition was not required for pH control in the low CO2 conditions, and therefore lactate reproduction was correlated with base addition under poor mixing conditions. Under good mixing conditions, CO2 -triggered base addition did not significantly impact lactate reproduction. It is reasonable to postulate that increased mixing times further promoted lactate production during base addition. As lactate reproduction results in more base addition to maintain pH, a cycle could be formed between lactate production and base addition. As a remediation, we showed that such lactate reproduction could be eliminated by improving CO2 removal at 2,000 L scale. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:756-766, 2018.

Emerging organic contaminants in vertical subsurface flow constructed wetlands: influence of media size, loading frequency and use of active aeration.

Four side-by-side pilot-scale vertical flow (VF) constructed wetlands of different designs were evaluated for the removal of eight widely used emerging organic contaminants from municipal wastewater (i.e. ibuprofen, acetaminophen, diclofenac, tonalide, oxybenzone, triclosan, ethinylestradiol, bisphenol A). Three of the systems were free-draining, with one containing a gravel substrate (VGp), while the other two contained sand substrate (VS1p and VS2p). The fourth system had a saturated gravel substrate and active aeration supplied across the bottom of the bed (VAp). All beds were pulse-loaded on an hourly basis, except VS2p, which was pulse-loaded every 2h. Each system had a surface area of 6.2m(2), received a hydraulic loading rate of 95 mm/day and was planted with Phragmites australis. The beds received an organic loading rate of 7-16 gTOC/m(2)d. The sand-based VF (VS1p) performed significantly better (p<0.05) than the gravel-based wetland (VGp) both in the removal of conventional water quality parameters (TSS, TOC, NH4-N) and studied emerging organic contaminants except for diclofenac (85 ± 17% vs. 74 ± 15% average emerging organic contaminant removal for VS1p and VGp, respectively). Although loading frequency (hourly vs. bi-hourly) was not observed to affect the removal efficiency of the cited conventional water quality parameters, significantly lower removal efficiencies were found for tonalide and bisphenol A for the VF wetland that received bi-hourly dosing (VS2p) (higher volume per pulse), probably due to the more reducing conditions observed in that system. However, diclofenac was the only contaminant showing an opposite trend to the rest of the compounds, achieving higher elimination rates in the wetlands that exhibited less-oxidizing conditions (VS2p and VGp). The use of active aeration in the saturated gravel bed (VAp) generally improved the treatment performance compared to the free-draining gravel bed (VGp) and achieved a similar performance to the free-draining sand-based VF wetlands (VS1p).

Repair of the injured spinal cord. A joint approach of basic and clinical research.

The myelin protein Nogo-A is a potent inhibitor of neurite outgrowth in the central nervous system, thus contributing to the incapacity of fiber tracts in the adult spinal cord to regenerate after injury. In this review we report on a joint approach of different research groups to develop a therapy applying anti-Nogo-A antibodies to the injured spinal cord. While basic researchers took the initiative to provide means of neutralizing the inhibitory effect of Nogo-A and demonstrated enhanced fiber growth, regeneration and functional recovery both in rodent and primate models, clinical groups and rehabilitation engineers have sought to translate this novel strategy into a clinical setting.

Extraction of heavy metals from soils using biodegradable chelating agents.

Metal pollution of soils is widespread across the globe, and the clean up of these soils is a difficulttask. One possible remediation technique is ex-situ soil washing using chelating agents. Ethylenediaminetetraacetic acid (EDTA) is a very effective chelating agent for this purpose but has the disadvantage that it is quite persistent in the environment due to its low biodegradability. The aim of our work was to investigate the biodegradable chelating agents [S,S]-ethylenediaminedisuccinic acid (EDDS), iminodisuccinic acid (IDSA), methylglycine diacetic acid (MGDA), and nitrilotriacetic acid (NTA) as potential alternatives and compare them with EDTA for effectiveness. Kinetic experiments showed for all metals and soils that 24 h was the optimum extraction time. Longer times only gave minor additional benefits for heavy metal extraction but an unwanted increase in iron mobilization. For Cu at pH 7, the order of the extraction efficiency for equimolar ratios of chelating agent to metal was EDDS > NTA> IDSA > MGDA > EDTA and for Zn it was NTA > EDDS > EDTA >MGDA > IDSA. The comparatively low efficiency of EDTA resulted from competition between the heavy metals and co-extracted Ca. For Pb the order of extraction was EDTA > NTA >EDDS due to the much stronger complexation of Pb by EDTA compared to EDDS. At higher concentration of complexing agent, less difference between the agents was found and less pH dependence. There was an increase in heavy metal extraction with decreasing pH, but this was offset by an increase in Ca and Fe extraction. In sequential extractions EDDS extracted metals almost exclusively from the exchangeable, mobile, and Mn-oxide fractions. We conclude that the extraction with EDDS at pH 7 showed the best compromise between extraction efficiency for Cu, Zn, and Pb and loss of Ca and Fe from the soil.