Remission spectra

The point symmetry of the octahedral sites in the spinel-structure is Dsd- While the octahedra are perfect for an oxygen parameter u of 3/8, they are compressed along a threefold axis for u < 3/8, and expanded for u > 3/8. In the case of MgCr204 ( a0,385) and MgAl204 (21 = 0,387) ( normal spinels with Mg + in tetrahedral and Cr +, Al + in octahedral sites), the expansion is of the magnitude of about 4 to 5%. The corresponding splitting effects of the second absorption band in the remission spectra of the mixed-crystal powders (Mg)( > (Cr jAL-x) O4 (13) are about... 

The distribution of adsorbent grain size must be standardised and air humidity and pH conditions reproducible if remission spectra are to be quantitatively evaluated. Water, for example, partly displaces the adsorbed substance molecules and thereby alters the form of the spectra [373]. Frei and co-workers [201] have investigated the reflectance spectra of some dyes adsorbed on Merck alumina, as a function of its thermal pre-treatment. They tested also the influence of neutral, acid or basic alumina on the form of the spectra. Modifications were observed due to interactions between adsorbed substance and adsorbent (chemisorption). 

It is only partly known how far the mentioned laws for powders can be adapted to direct evaluation of the remission spectra of spots on adsorbent layers. It has been established from corresponding studies of paper chromatograms that the Kubelka-Munk function is valid only in particular regions of low concentration [372]. Jork [333 a] has found linear dependence of degree of remission on applied substance amount over relatively wide ranges of concentration. He studied substances from... 

Remission spectra can also be recorded and used for detection without loss of material, especially in the UV region [114]. 

The vitamins and the amino acids formed by their decomposition, can be semi-quantitatively determined by comparing the ninhydrin-coloured spots with those from a series of standards of the pure substances [8, 103]. Suggestions about evaluation after elution are given in [103]. Feei and Frodyma [48] have measured the remission spectra of the stable ninhydrin-amino acid complexes on the layer, in order to determine them with high accuracy and precision. 

Figure 19-4 Optical constants (a) and remission spectra (1 10 Ti02) (b) of P.Y. 138.

The remission spectra (Figure 19.4) can be elegantly interpreted by means of the optical constants, on the basis of Mie s theory. Small remission values for blue light, due to the solid-state absorption band (40-460 nm) are followed by a steep incline at 500 nm. At longer wavelengths the optical window is open to green and red light, which can be scattered effectively by the TiOj particles of the white reduction. 

If over the region of interest, the scattering coefficient hardly varies with wavelength, the shapes of the remission spectrum and the absorption spectrum should be very similar. The relationship between the remission function and the reflectance spectrum is shown in Figure 7.2 left, and the Kubelka-Munk functions of the different iron oxides are illustrated in Figure 7.2, right. 

The spectrum of Systemic Lupus Erythematosus (SLE) includes latent lupus, discoid lupus, drug-induced lupus, neonatal lupus, lupus profundus, neuropsychiatric lupus, lupus vasculitis, pulmonary lupus, etc. The disease course is characterized by unpredictable exacerbations, drug-induced remissions and spontaneous remissions. SLE is characterized by a wide range of variable individual clinical manifestations which are controllable at early stages. 

Various forms of cancer exhibit a broad spectrum of response to antineoplastic medications. Some forms of cancer (choriocarcinoma, Wilms tumor) can be cured in more than 90 percent of affected patients. In other neoplastic disorders, chemotherapy may not cure the disease but may succeed in mediating remission and prolonging survival in a large patient percentage. Of course, other factors such as early detection and the concomitant use of other interventions (surgery, radiation) will greatly influence the success of chemotherapy drugs. 

Both the physician and the patient are confronted with a wide range of unconventional therapeutic measures. It is understandable that patients and their relatives resort, in their desperation, to any methods which may offer a therapeutic chance We have nothing to lose, but maybe we can defeat the cancer in the end time and again, one hears of such healing or remission. And which doctor would want to destroy hope even in the face of oncological reality The alternatives indeed cover a broad spectrum, (s. tab. 37.10)... 

Among the newer untineoplustic drugs. 4-l(9-acridinyl)-amino mcthancsulfon- i-anisididc (m-AMSA) showed a wide spectrum of activity in early clinical trial.s. It afforded. some remissions in refractory cases of breast cancer, malignant melanoma, and acute myelocytic leukemia. Leukopenia is the limiting toxicity. ... 

The biological interest of acronycine was revealed in 1966 by Svoboda at the Eli-Lilly Laboratories (27, 28). Acronycine was found to be active against a broad spectrum of solid tumors including sarcoma, myeloma, carcinoma and melanoma. In contrast, it only exhibited poor activity against leukemias. The activity against X-5563 myeloma was of particular interest, since this plasma cell tumor has several properties that relate to those of multiple myeloma in human patients. This is the reason why Scarffe in 1983 (29) performed phase I-II clinical evaluation of acronycine in patients with refractory multiple myeloma. Oral acronycine capsules produced one clear response in sixteen patients. The remission was maintained 72 weeks, using daily dose of 300 mg/m. The limited success of that trial is probably related to the moderate potency of acronycine and to its very low water-solubility (cfl. 2-3 mg per liter of water) which do not permit an efficient parenteral formulation of the drug. 

Leprosy is a continuum between two extremes. At one end of the spectrum is tuberculoid leprosy, characterized by skin macules with clear centers and well-defined margins. M. leprae is rarely found in smears made from quiescent lesions but may appear during activity. Noncaseating foci are present. The patient s cell-mediated immunity is normal, and a skin test for infection by leprosy is invariably positive. The disease is characterized by prolonged remissions with periodic reactivation. 

The chnical spectrum of activity for cyclophosphamide is very broad. It is a component of many effective drug combinations for non-Hodgkin s lymphomas, ovarian cancers, and solid tumors in children. Complete remissions and cures have been reported when cyclophosphamide was given as a single agent for Burkitt s lymphoma. It frequently is used in combination with methotrexate (or doxorubicin) and fluorouracil as adjuvant therapy after surgery for breast cancer. 

Fig. 2 Spectrodensitograms (A) and densitograms (B) of 10 mg arbutin (Camag TLC Scanner slit dimensions 6.00 X 0.30 mm, Micro scanning speed 20 mm/sec for detection and 20 nm/sec for spectrum scan data resolution 100 mm/step for detection and 1 nm/step for spectmm scan A = 285 nm deuter lamp measurement type remission measurement mode absorption).

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