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The yield of cultures of Emiliania huxleyi, a coccolithophore marine micro-alga species, in natural seawater and in seawater previously exposed to elutriates of ZEBEN-06 and ZESTEC-56, two zeolitic-nature products (ZNPs) (supernatant of 2.0 g l-1 of ZNP in natural seawater, stirred for 30 min) was evaluated. Total concentrations of dissolved trace metals and organic ligands (and respective conditional stability constants) in the initial media and at 7th day cultures were determined, by anodic and cathodic striping voltammetry. The changes introduced by the ZNPs in the media significantly enhanced E. huxleyi growth yield, the effect being more extent in the ZESTEC-56 elutriate. It was observed that both the ZNPs enriched the seawater with trace and not toxic quantities of Mn. In addiction, ZEBEN-06 removed small fractions of Cu and Zn from the media. The ZEBEN-06 elutriate stimulated the cell exudation but that of ZESTEC-56 inhibited exudation. Algae were also incubated in a culture medium with 0.05 g l-1 ZESTEC-56 in situ, and the growth yield was similar to that of the control culture. ZEBEN-06 was not studied in situ because it was hard to distinguish its particles from the cells, during cells counting. The ZESTEC-56 in situ enriched the medium in Mn, Cu, Pb and Cd, but impoverished it in Zn. The cell exudation was about four times higher in the presence of the ZNP in situ. Liberation/adsorption of micro-nutrients at the surface of the zeolites seems to be the cause of the observed changes in the biological response of the algae. The yield of the algal growth has economic relevance in aquaculture. On the other hand, ZNP are cheap, only small amounts (few mg l-1) are required and the addition of some nicro-nutrients may be omitted. Therefore, the inclusion of zeolites in algal cultures in aquaculture may be economically advantageous. However, it is recommendable an previous investigation, in order to select the zeolitic characteristics and concentration that will maximise the algal yield in each particular case (alga nature and seawater trace metal contents). [Copyright &y& Elsevier]

Abstract Zeolitic products were originally used as biological filters. These products are now used in other biological processes such as the transformation of ammoniun ions present in sea water into nitrite and the decomposition of fish feed. The application of zeolitic products has now been extended to the growth of marine microalgae cultures. The present paper describes the results obtained from cultures of the diatom Chaetoceros muelleri which was grown in artificial sea water in the presence of Zecer-56, a natural zeolitic product. Zecer-56 was found to significantly stimulate the growth of C. muelleri cultures. [ABSTRACT FROM AUTHOR]

In many real applications, the data of production processes cannot be precisely measured. This is particularly worrying when assessing efficiency with frontier-type models, such as data envelopment analysis (DEA) models, since they are very sensitive to possible data errors. For this reason, the possibility of having available a methodology that allows the analyst to deal with imprecise data becomes an issue of great interest in these contexts. To that end, we develop some fuzzy versions of the classical DEA models (in particular, the BCC model) by using some ranking methods based on the comparison of α-cuts. The resulting auxiliary crisp problems can be solved by the usual DEA software. We show, in a numerical example, how our models become specially useful for detecting sensitive decision-making units. Our approaches can be seen as an extension of the DEA methodology that provides users and practitioners with models which represent some real life processes more appropriately. [Copyright &y& Elsevier]

Purpose/objective(s): Stereotactic radiosurgery (SRS) requires very sharp dose gradients, high conformality and typically uses minimal expansion margins. Immobilization with an open face mask is more comfortable and less invasive than frame-based immobilization but concerns about intra-fraction motion must be addressed. Surface guided radiation therapy (SGRT) is an attractive option for intra-fraction patient monitoring because it is continuous, has sub-millimeter accuracy and uses no ionizing radiation. The purpose of this study was to investigate the dosimetric consequences of uncorrected intra-fraction patient motion detected during frameless Linac-based SRS.Materials/methods: All SRS patients (pts) were immobilized in an SRS-specific open face thermoplastic mask with bite plate and were monitored during treatment using SGRT with tolerances of 1 mm translations and 1° rotations; the treatment beam automatically turned off if these tolerances were exceeded. SRS pts received 18 or 21 Gy in 1 fraction or 27 Gy in 3 fractions based on tumor size and location. GTV to PTV margins ranged from 0 to 3 mm. Twelve pts were treated with circular cones and 13 were treated with MLC-based plans with the technique chosen based on PTV size. If the SGRT system detected motion greater than tolerance during treatment, conebeam CT(CBCT) was repeated and the necessary shifts were made prior to continuing treatment. For the 25 pts with intra-fraction 3D vector shifts of at least 1 mm, we offset the isocenter in the treatment planning system using the translational shifts from the repeat CBCT and re-calculated the plans with the planned MU to determine the dosimetric effect the shift would have caused had it not been detected. The GTV and PTV coverage and normal brain V12 for the shifted plans were compared to the planned values. Wilcoxon signed rank tests were used to compare planned and shifted dosimetric indices and median 2 sample tests were used to investigate these differences between cone and MLC plans.Results: From the recalculated plans, the resulting median V12 increased by 0.24 cc (P = 0.006) and the median GTV and PTV coverage decreased 9% (P < 0.001) and 10.2 % (P < 0.001), respectively. PTV coverage decreased more for shifted cone plans than for shifted MLC plans (11.6% vs 4.7%, P = 0.011) but the median V12 differences were found to be significantly larger for MLC plans (-0.34 cc vs -0.01 cc, P = 0.011), due to the sharper dose gradients and higher conformality for the cone plans compared to the MLC plans. Differences in GTV coverage between cone and MLC plans were not statistically significant.Conclusion: SGRT detected clinically meaningful intra-fraction motion during frameless SRS, which could potentially lead to large underdoses and increased normal brain dose if not corrected. Dosimetric differences between planned and shifted plans were statistically significant.Author Disclosure: R.D. Foster: None. B.J. Moeller: Independent Contractor; Novant Health. Partner; SERO. Stock; Moderna. M. Robinson: None. M. Bright: SEAAPM.J.L. Ruiz: Stock; Obseva USA, Inc. C.J. Hampton: None. J.H. Heinzerling: Research Grant; Vision RT, Inc, AstraZeneca. Honoraria; Vision RT, Inc, AstraZeneca. Consultant; Vision RT, Inc. [ABSTRACT FROM AUTHOR]