21. The isotope effect showed that materials with heavier ions ( different nuclear isotopes ) had lower superconducting transition temperatures. 22. Of the various theoretical treatments of kinetic isotope effects , Bigeleisen's seems to be the most popular. 23. The subscript " s " refers to these " semiclassical " kinetic isotope effects , which disregard quantum tunneling. 24. In addition, strong isotope effects observed affect the retention time of differently labeled isotopomers in the GC column. 25. A generalized treatment of kinetic isotopic effects is via the GEBIK and GEBIF equations describing transient kinetic isotope effects . 26. Hydrogen Minerals generally have large isotope effects , and the isotopic composition often follows the pattern observed for precipitation. 27. This mechanism is contested by a possible alternative 13 C and deuterium kinetic isotope effects points toward the aldol mechanism. 28. A stepwise or a largely asynchronous mechanism has been proposed for the catalyzed reaction based on kinetic isotope effect studies. 29. Hence, more often than not, weakening of bending frequencies is not an important cause of large kinetic isotope effects . 30. Transpiration exhibits a normal isotope effect , causing enrichment of deuterium in plant leaf water and therefore enrichment of leaf waxes.
