A Film Diffusional Effect on the Apparent Kinetic Parameters in Packed-Bed Immobilized Enzyme Reactors

Miyakawa, Hiromitsu; Shiraishi, Fumihidé

doi:10.1002/(sici)1097-4660(199708)69:4<456::aid-jctb734>3.0.co;2-e

Cited by 4 publications

(2 citation statements)

References 7 publications

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“…These values can only be matched by packed‐bed reactors when mass‐transfer limitations are negligible and the substrate concentration is sufficient (see below) 33. To determine when mass transfer limitations become negligible one can increase the flow rate through the packed bed in steps, and observe the rate of reaction achieved 34, 35. The performance of the batch reactions should be approached at high‐flow rates in the packed bed.…”

Section: Resultsmentioning

confidence: 99%

Cancer in Fanconi anemia, 1927–2001

Alter

2003

Cancer

405

267

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BACKGROUND. Fanconi anemia (FA) is an autosomal recessive disease associatedwith an abnormal response to DNA damage. Although FA is well known for the association of aplastic anemia and characteristic birth defects, leukemia and solid tumors also occur at a high rate in this group of patients. A review of all reported cases is informative with regard to the specific types of cancer, the ages at which they occur, and the cumulative probability of their development. METHODS.Medline and bibliographies of publications were searched for articles containing "Fanconi's anemia" or "aplastic anemia" and all cases of FA from 1927 through 2001 were included in the database. Cancer cases were identified within these reports. Descriptive statistical analyses were performed using Stata7 software. RESULTS.One thousand three hundred cases of FA were identified. Nine percent had leukemia (primarily acute myeloid leukemia), 7% had myelodysplastic syndrome, 5% had solid tumors, and 3% had liver tumors. Patients with cancer were older than the cancer-free patients at the time of diagnosis of FA. The median age for cancer (including leukemia) was 16, compared with 68 in the general population. The most frequent solid tumors were aerodigestive and gynecological carcinomas. In approximately 25% of patients with cancer, the malignancy preceded the diagnosis of FA. CONCLUSIONS.If the competing risks of aplastic anemia and leukemia could be removed, the estimated cumulative probability of development of a solid tumor in

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Section: Resultsmentioning

confidence: 99%

Cancer in Fanconi anemia, 1927–2001

Alter

2003

Cancer

405

267

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“…This plug-flow equation neglects any effects of diffusion of the substrate to the active surface and therefore when it is used to model the dependence of substrate conversion rate with initial substrate concentration, the apparent enzyme kinetic constants, in particular K M , depend on the length of the enzyme reactor [13,21] or the flow rate used [22][23][24]. Under certain conditions, groups have reported no effect of flow rate [25,26], confirming that there may be conditions where the effects of mass transport are negligible.…”

Section: Enzyme Immobilisationmentioning

confidence: 99%

The ‘free-flow’ biosensor in enzyme inhibition assay

Hatz

Hall

2006

Sensors and Actuators B: Chemical

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Fumed silica activated subtilisin Carlsberg in hexane in a packed‐bed reactor

Pfromm¹,

Rezac²,

Würges³

et al. 2006

AIChE Journal

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in Wiley InterScience (www.interscience.wiley.com).Enzymatic catalysis in organic solvents can enable applications, reactivities, and selectivities that are not accessible in water. The use of enzymes for catalysis in organic solvents has been somewhat hampered by their relatively low-catalytic activity. A new preparation of the enzyme subtilisin Carlsberg (SC) with fumed silica as support (FS) has been developed. This preparation matches and sometimes exceeds the activity of some of the best reported preparations of the same enzyme for use in solvents. The usefulness of our preparation in a packed-bed reactor is explored here. The catalytic characteristics of our preparation containing 5 wt % of enzyme/95 wt % FS in a packed-bed reactor for a model transesterification in hexane is determined. Mass-transfer limitations are explored, and a comparison to batch results is given. The activity of our preparation after prolonged storage as a packed bed is investigated. Our immobilized enzyme preparation may be a step towards more economical enzymatic catalysis in organic solvents.

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A Film Diffusional Effect on the Apparent Kinetic Parameters in Packed-Bed Immobilized Enzyme Reactors

Cited by 4 publications

References 7 publications

Cancer in Fanconi anemia, 1927–2001

Cancer in Fanconi anemia, 1927–2001

The ‘free-flow’ biosensor in enzyme inhibition assay

Fumed silica activated subtilisin Carlsberg in hexane in a packed‐bed reactor

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