absorptive state

Examples of absorptive state in the following topics:

• Absorptive State

  • When the gastrointestinal tract is full, anabolism exceeds catabolism; this is the absorptive state.
  • Absorptive state is the period in which the gastrointestinal tract is full and the anabolic processes exceed catabolism.
  • The glycogen and fat will be stored in the liver and adipose tissue, respectively, as reserves for the post-absorptive state.

• Postabsorptive State

  • The post-absorptive state occurs around three to five hours after a meal has been completely digested and absorbed.
  • The metabolic state achieved after complete digestion and absorption of a meal.
  • Several metabolic adjustments occur during fasting, and some diagnostic tests are used to determine a fasting state.
  • Metabolic changes toward the fasting state begin after absorption of a meal (typically three to five hours after a meal); "post-absorptive state" is synonymous with this usage, in contrast to the "post-prandial" state of ongoing digestion.
  • During fasting, post-absorptive state, fatty acid oxidation contributes proportionately more to energy expenditure than does carbohydrate oxidation.

• Malabsorption of Nutrients

  • Malabsorption is a state arising from abnormality in absorption of food nutrients across the gastrointestinal (GI) tract.
  • Until the 1970s, it was assumed by scientists and medical professionals in the United States that all children (except a very few with allergies) could drink milk without problems.
  • Malabsorption is a state arising from abnormality in absorption of food nutrients across the gastrointestinal (GI) tract.
  • These symptoms are due to impaired water, carbohydrate, and electrolyte absorption; or irritation from unabsorbed fatty acids.
  • People whose absorptive surfaces are severely limited from disease or surgery may need long term total parenteral nutrition.

• UV-Visible Absorption Spectra

  • As a rule, energetically favored electron promotion will be from the highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO), and the resulting species is called an excited state.
  • An optical spectrometer records the wavelengths at which absorption occurs, together with the degree of absorption at each wavelength.
  • Absorbance usually ranges from 0 (no absorption) to 2 (99% absorption), and is precisely defined in context with spectrometer operation.
  • Molar absorptivity (ε) is defined as:
  • Molar absorptivities may be very large for strongly absorbing chromophores (>10,000) and very small if absorption is weak (10 to 100).

• The Importance of Conjugation

  • Also, the molar absorptivity (ε) roughly doubles with each new conjugated double bond.
  • This fine structure reflects not only the different conformations such systems may assume, but also electronic transitions between the different vibrational energy levels possible for each electronic state.
  • The π __> π* absorption located at 242 nm is very strong, with an ε = 18,000.
  • The weak n __> π* absorption near 300 nm has an ε = 100.
  • Benzene exhibits very strong light absorption near 180 nm (ε > 65,000) , weaker absorption at 200 nm (ε = 8,000) and a group of much weaker bands at 254 nm (ε = 240).

• Group Frequencies

  • Detailed information about the infrared absorptions observed for various bonded atoms and groups is usually presented in tabular form.
  • Following the color scheme of the chart, stretching absorptions are listed in the blue-shaded section and bending absorptions in the green shaded part.
  • Since most organic compounds have C-H bonds, a useful rule is that absorption in the 2850 to 3000 cm-1 is due to sp3 C-H stretching; whereas, absorption above 3000 cm-1 is from sp2 C-H stretching or sp2 C-H stretching if it is near 3300 cm-1.
  • Infrared absorption data for some functional groups not listed in the preceding table are given below.
  • Most of the absorptions cited are associated with stretching vibrations.

• Bulk Flow: Filtration and Reabsorption

  • Alternatively when moving from the interstitium into the bloodstreatm the process is termed re-absorption and is favoured by blood oncotic pressure and interstitial fluid hydrostatic pressure.
  • This indicates that capillaries are normally in a state of filtration along their entire length.
  • Tubular re-absorption is the process by which solutes and water are removed from the tubular fluid and transported into the blood.
  • Re-absorption is a two-step process beginning with the active or passive extraction of substances from the tubule fluid into the renal interstitium, and then the transport of these substances from the interstitium into the bloodstream

• Einstein Coefficients

  • Kirchoff's law yields a relationship between the emission and absorption coefficients for a thermally emitting material, specifically $j_\nu = \alpha_\nu B_\nu$.
  • This relationship suggests some connection between emission and absorption at a microscopic level.
  • You can think of the statistical weight as the number of ways that the atom can be in the particular state, the degeneracy of the state.
  • If we calculate the probability of absorption of a photon for example, we can use the Einstein relations to find the rate of stimulated and spontaneous emission.

• LTE

  • In this case the ratio of the number of atoms in the various states is determined by the condition of thermodynamic equilibrium

• Color

  • Transition metal complexes are often colored due to either d-d or change band electron transitions induced by the absorption of light.
  • Metal complexes often have spectacular colors caused by electronic transitions induced by the absorption of light.
  • These are most likely to occur when the metal is in a low oxidation state and the ligand is easily reduced.
  • These can most easily occur when the metal is in a high oxidation state.
  • The color we see for coordination complexes is a result of absorption of complimentary colors.