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It is shown that near normal incidence, low‐energy electron excitation of Al on silicon surfaces by ultra‐soft X‐Ray emission spectroscopy yielded limits of detectibility (LD) in the picogram region. This result on L band emission via electron excitation is fully competitive with photon excitation using K‐α lines via grazing incidence total reflection techniques (TXRF). Surprisingly, it was also found that normal incidence synchrotron photon excitation on the same sample yielded much higher values of LD than low‐energy electron excitation, undoubtedly due to the use of a poor transmission grating used in the entrance optics.

The Mn Lα and Lβ spectra of Mn, MnO, Mn3O4, Mn2O3, and MnO2 have been measured. Each Mn La spectrum has been deconvoluted into two bands, LαA and LαB, and the integrated LαA/LαB intensity ratio was found to be inversely proportional to the Mn-0 inter-atomic distance, but proportional to the oxidation number. This finding tends to indicate the likelihood of crossover transition from oxygen to manganese. The intensity ratio Lβ/LαB of the pure metal was found to coincide closely with the statistically predicted value of 0.5. Furthermore, for Mn-metal, as well as for the oxides, the shift of the LαA band from the LαB band was found to agree with the change in the Lβ/Lα peak intensity ratio as a function of oxidation number.

The variable-exit-angle ultrasoft x-ray fluorescence technique has been evaluated for Ni/Fe thin-film multilayers. The theoretical and experimental agreement is reasonable. The experimental results demonstrate that on these Ni/Fe samples quantitative information can be obtained in the presence of surface contamination.

The oxidation of Fe has been characterized qualitatively by variable exit angle ultrasoft X-ray fluorescence spectroscopy (USXFS). The results indicate that the Lβ/Lα intensity ratio can be used to evaluate the extent of Fe oxidation and that the oxidation is believed to penetrate to a certain degree within Fe such that discrete Fe oxide layers are not formed.

A general theoretical treatment is offered to obtain the critical depth (dc) values of the characteristic K, L and M x-ray fluorescence signals as a function of sample grazing incidence angle (θi′), exit angle (θe′) and atomic number Z. It is shown, for example, that for θe′ = 1° and θi′ = 89° in going from Z = 5 to Z = 74, dc values range from 102 to 104 A for K emission, from 30 to 500 A for L emission, and from 10 to 50 A for M emission provided 99% of the emerging radiation is accounted for. Detailed calculations are offered for cases when a smaller fraction of the outgoing radiation is considered. Critical depth calculations are also offered for single and multilayer thin films. The effect surface roughness has on the critical depth and the dc dependence on energy are also examined. Finally, the depth resolution is calculated for a given angular definition.

In connection with their air pollution studies, experiments have been carried out to ascertain the room temperature adsorption of carbon monoxide, carbon dioxide, water vapor, acetaldehyde, and sulfur dioxide on marine ferro-manganese crusts, and on certain synthetically produced Mn bearing substances. Results have been compared with adsorption data on mesoporous zeolites. Limited desorption data were obtained on most of these materials. In addition, kinetics data of adsorption and desorption were also obtained on select ferro-manganese materials. The room temperature adsorption data on a select ferro-manganese material reached equilibrium-specific: adsorptivity values above 0.4 grams/gram of adsorbent at 600 torr of pressure of gas for sulfur dioxide and acetaldehyde. All of the other gases tested show much lower values. The equilibrium values at 50 torr pressure were about 0.25 for sulfur dioxide and about 0.05 for acetaldehyde. The adsorption kinetic studies conducted at room temperature on the select ferro-manganese material indicated that sulfur dioxide was adsorbed the fastest, followed by carbon dioxide, acetaldehyde, and water vapor, with sulfur dioxide reaching 99.9% adsorption in 4 minutes and water vapor in 12 minutes. Thermal desorption studies conducted on the select ferro-manganese material indicated for water four unresolved bands, going from about 50 to 230/spl deg/C, for acetaldehyde two broad but resolved bands one at about 90 and the other at about 140/spl deg/C. The significance of the findings of adsorption at low pressures indicated a more favorable situation for ferro-manganese crust materials in air pollution control of sulfur dioxide in certain vehicular emissions.

Essentially distortion-free imaginary dielectric index spectra have been obtained for LiF from Kramers-Kronig ( KK ) dispersion analysis of I.R. reflectance data at 300 K, 80 K and 20 K. The frequency dependence of the damping function as well as the temperature dependence of the various dispersion parameters of the first transverse optic mode have been illustrated. The effective damping constant \ gg o , and the resonance frequency ν o , are found to be in satisfactory agreement with the theoretical calculations.

A quantitative method has been developed for characterizing the extent of Cu oxidation by variable exit angle ultrasoft X-ray fluorescence spectroscopy (USXFS). The results indicate that the Lβ Lα intensity ratio can be used to evaluate the degree of Cu chemical modification. The theoretical treatment suggests the Cu depth resolution obtained with this technique is on the order of 10 A.

A method is developed for the simultaneous determination of neopynamine and piperonyl butoxide by chromatography on a quartz capillary column using flame ionization detection. Benzyl mandelate is used as an internal standard. Calibration graphs are linear down to at least 3.75 mg% and 3 mg% for neopynamine and piperonyl butoxide, respectively.

Synopsis Benzoyl peroxide has been used for over 20 years to treat youthful acne. The aim of this study is to determine its release rate from the vehicle that allows it to reach and treat the skin (topical availability) and its ability to pass through the skin and reach the general circulation (bioavailability), in order to bring about good topical availability, linked to bioavailability or, an 'abioavailability'. Three preparations containing 10% of benzoyl peroxide were administered to the back of shaven New Zealand rabbits. At day 0, day 5, day 12, day 19, day 26 and day 33, the topical effects were measured by cutaneous temperature, degree of erythema and the benzoic acid plasma record card, which shows blood sample results of the metabolism of the drug. The results obtained show that the topical availability of benzoyl peroxide coincides with a decrease in cutaneous temperature, after application in various dosage forms, in spite of the appearance of a marked erythema. The bioavailability is demonstrated by plasma benzoic acid evaluation. Before administration, benzoic acid levels are low but increase half an hour after administration, to reach a maximal level at 3 h. Benzoyl peroxide metabolizes quickly and does not seem to be able to cross the skin without being changed.

Determination of free and conjugated cis-3,3,5-trimethylcyclohexanol in plasma and urine A gas chromatographic procedure was developed to determine free and conjugated cis-3,3,5-trimethylcyclohexanol in plasma and urine. The sample is extracted with dichloromethane when free cis-3,3,5-trimethylcyclohexanol is determined, or with hexane after enzymatic hydrolysis, when conjugated cis-3,3,5-trimethylcyclohexanol is determined. An aliquot of the organic extract is injected into a stainless-steel column (packed with Carbowax 20M, 15% on Chromosorb W AW 100–120 mesh) and detected with a flame ionization detector. Extraction recovery from plasma and urine was almost 100% and the limit of quantification was fixed at 100 ng/ml plasma or urine. The procedure was evaluated in a pharmacokinetic study of cyclandelate and its metabolite cis-3,3,5-trimethylcyclohexanol.

Using our recently developed high resolution 5 M grating spectrograph we have reported previously on the capabilities of photographic detection for obtaining molecular x-ray fluorescence spectra.(1,2) Accordingly, we indicated that in spite of a relatively inexpensive monochromator source the signal to noise ratio on O K in Li3 PO4 at equivalent instrumental resolution was of the same order of magnitude as that obtained by Wiech's group using photoelectric detection and the DORIS storage ring as a, source.(3)

Both O K and Cu L α X-ray fluorescence spectra of Cu 2 O and CuO at room temperature were obtained using suitable X-ray photon excitation sources. Non-empirical Hartree-Fock molecular orbital calculations on small copper-oxygen clusters are also reported. The valence molecular orbitals which are responsible for various features of the experimental spectra have been identified with reasonable correlation between theory and experiment for all the spectra.

Description de la methode theorique. L'approche theorique est basee sur le rapport de l'intensite de la couche a celle de l'etalon interne ou externe ou a celle d'une autre couche de l'echantillon. Presentation de resultats experimentaux sur des multicouches Fe-Ni

A method was developed for the simultaneous determination of cyclandelate and mandelic acid concentrations in plasma, involving extraction from plasma followed by trimethylsilylation and chromatography of the derivatives on a glass capillary column with hydrogen flame-ionization detection. Calibration graphs were linear down to at least 20 μg/ml for each substance. The precision was excellent with a pooled relative standard deviation of 6.3% and 6.4% for cyclandelate and mandelic acid serum samples, respectively. Concentrations below 500 ng/ml of each substance could be detected in human plasma. The method was developed for use in bioavailability and metabolism studies.

Accurate measurements of the reflectance of the (100 face) of NaCIO3 single crystals have been made in the infrared region of 400–1400 cm−1, which includes all the fundamental vibrations of the C1O3− ion. Optical indices for this region have been calculated using the Kramers-Kronig relation. Secondary optical constants have been obtained from the indices of absorption and refraction. They include line strengths, damping coefficients, transverse and longitudinal frequencies and the static dielectric constant. Some conclusions concerning the dipole derivative with vibrational coordinate of an isolated ion are presented, and the splitting of v3 is concluded to be primarily due to dipole-dipole coupling in the crystal.

The application of the newly developed self-bracketing search (SBS) classical dispersion (CD) analysis on published reflectance data of the internal modes of NaClO 3 indicates a plausible presence of anharmonic coupling in the v 1 , v 3a,b region. The above SBS-CD analysis has also resulted in the evaluation of the dispersion parameter values for the internal modes of NaClO 3 , and has provided the first quantitative determination of these values for the 37 Cl isotope.

A self-bracketing search technique employing classical dispersion analysis is used to calculate dispersion parameter values by minimizing the deviation between experimental and calculated reflectance or transmission data. An evaluation of the method on multiband spectra is accomplished by using synthetic spectra that contain both overlapping and nonoverlapping band systems. The experimental spectra are obtained by measuring the reflectance at normal incidence from a large single crystal or by measuring the transmittance of a thin film deposited on a transparent substrate. Upon application of the technique to real spectra, the deviation between the calculated and real spectra produces a constant value rather than approaching zero, as is the case with synthetic spectra. Reasons for this phenomenon are discussed.

The resonant frequencies, damping constants and oscillator strengths of far infrared lattice vibrations of polycrystalline NaClO3, KClO3, NaBrO3 and KBrO3 have been obtained through classical dispersion (CD) analysis of transmission data. Space group analysis has been applied for attribution assignments and to ascertain the translational and rotational character of the respective lattice bands. The damping constants were found to be unusually large indicating short lifetimes of the excited states in spite of an apparent absence of phonon-phonon coupling. The CD analysis of the spectra also provide reliable values of oscillator strength and resonant frequency.

A vertically oriented double‐crystal attachment was designed and constructed for use on a standard Norelco vacuum x‐ray spectrograph. The attachment achieves the mechanical stability and performance of similar horizontal attachments. It yields usable intensities and resolutions of 1–2 eV, thus providing capabilities for studying molecular x‐ray spectra.

Capacitance measurements on thin, fully depleted GaSe samples indicate a low frequency dielectric constant ϵ_0 = 8.0 ± 0.3 for E||c. Infrared reflectivity measurements show a single resonance for each polarization of the electric vector. Dispersion analysis gives ϵ_∞ = 7.1 and ϵ_0 = 7.6 for E||c and ϵ_∞ = 8.4 and ϵ_0 = 10.2 for E⊥c. More accurate channel spectra give ϵ_∞ = 7.45 and ϵ_0 = 9.80 for E⊥c. A number of weak two phonon combination bands are observed.

This paper attempts to evaluate the reliability of classical dispersion (CD) analysis to obtain accurate values of the dispersion parameters in general and of the damping constant in particular for strongly anharmonic lattice vibrations. We have carried out this reliability evaluation by applying a newly developed CD analysis technique to process LiF and MgO i.r. reflectance data measured by Jasperse, Kahan, Plendl and Mitra (JKPM). This study demonstrates that our new technique yields approximately the same values for oscillator strength and for resonance frequency as those reported by the JKPM group. However the damping constant values obtained by the two different techniques are in significant disagreement with one another. This finding leads to the conclusion that CD analysis is not very reliable for obtaining accurate values of the damping constant for strongly anharmonic lattice modes of ionic crystals, such as LiF and MgO.

The “degree of internal standardization” for the scattered radiation method of compensation for matrix effects in x-ray fluorescence analysis is defined as the closeness of agreement between the results of analyses of specimens containing identical concentrations of analyte but with differing over-all elemental constituencies. The definition is derived in mathematical terms and is applied to experimental data of analyses of calcium in aqueous solutions containing different dissolved substances as matrix variants. The matrix compensation effectiveness of various wavelengths of scattered radiation can be clearly indicated. Interpretation of the results in terms of basic spectroscopic parameters is offered.

With the introduction in 1960 of the first commercial multichannel vacuum X-ray spectrometers, ARL opened the way for greater economy of operation for light-element analysis over conventional helium-path instrumentation. The design concepts and features of these instruments are discussed, including the adaptability to “on-stream” or continuous analyzer programs. The successful application of vacuum X-ray equipment for the analysis of ores, concentrates, and slags will be presented. Factors relating to sample preparation, precision, and accuracy are given and analytical sensitivity and speed are covered.

A colorimetric determination of chlorhexidine is described. The method is based on the formation of a yellow complex between the drug and bromcresol green. The absorption peak of this complex, extracted by chloroform, is at 410 nm, and linear response is obtained from 2.5 to 30 micrograms of chlorhexidine/ml. The accuracy and reproducibility of this rapid method make it useful for chlorhexidine determination in the manufacturing control of pharmaceutical mixtures.

Polycrystalline thin films of alkali halogenates have been prepared by a solvent-evaporation technique. Refinement of the technique has enabled us to produce a uniform thin film free of the Christiansen effect. The film thicknesses have been measured by x-ray fluorescence to be from 0.4 to 1.0 µ, with an estimated error of less than 2%. The technique is based on the deposition of a thin film on a high-density polyethylene substrate making it possible to study quantitatively the external vibrational modes and those internal modes of potassium and sodium halogenates which have a resonant frequency of less than 600 cm−1.

Ocular surface drying was studied in rabbits using an experimental model of blinking interruption. This model produces a discontinuity in the pre-corneal tear film after a few minutes of exposure to air. Changes in superficial epithelial cell structure were studied using a scan microscope. A decrease of micro-folds and an increase in epithelial cell desquamation were observed. Prolonged exposure to air produced similar cellular lesions in deeper layers. The instillation of a single mucomimetic eye-drop containing chondroitin sulphate prevented total interruption of epithelial humidification, kept the epithelial surface intact and preserved normal cellular structure.

To date the production of molecular x-ray emission satellites has been rationalized in terms of one-center core vacancy initial states.1 In view of the low frequency satellites reported by Agren et al.2 and because of the nature of the satellites recently observed in our laboratory3, it behooves to consider the possibility of satellites created by two center vacancy (TCV) initial states.

In this study the authors compared the pharmacokinetics of three zinc salts after parenteral and oral administration to rabbits: zinc sulfate, a soluble mineral salt; zinc pantothenate, a soluble organic salt; and zinc orotate, an insoluble organic salt. The results obtained with the two soluble salts were not significantly different (p less than 0.05). Therefore they appear to be bioequivalent. The plasma concentration curve for zinc orotate shows a faster distribution (alpha) and elimination phase (beta) after parenteral administration, and a slower absorption phase (Ka) after oral administration, when compared with that of the other two salts. It was shown that the dissolution behaviour of these zinc salts in water does not correlate with the parameters found in vivo.

Three tests were utilized to determine and compare the toxicity of timolol, propranolol and two new aliphatic and alicyclic oxime ethers with beta-blocking activity (falintolol and compound POS 7). Effects on the electrical potential difference across the in vitro bovine corneal epithelium. Local anaesthesia on in vivo rabbit cornea. Antimicrobial activity on bacterial and fungal suspensions. In addition, partition coefficients were determined as physicochemical properties of the drugs. Falintolol, as well as timolol produced a minor change in electrophysiology at clinical concentration. They had neither local anaesthetic, nor antimicrobial effects. Conversely, propranolol and compound POS 7 showed acute corneal toxicity in the present models. It was concluded that changes in the potential difference across a perfused cornea in vitro, local anaesthesia and bacterial inhibition, might be a demonstration of the cytotoxicity of certain topical agents in terms of acute eye tissue reaction. They might represent a valuable model for the acute corneal toxicity evaluation of topical beta-blockers.

The antiglaucomatous effects of Glauplex 2 and pilocarpine nitrate on alpha-chymotrypsine-induced experimental glaucoma were studied in 8 rabbits. Changes in intraocular pressure were measured over a period of 12 hours after a single instillation of Glauplex 2 or two instillations of 2.6 p. cent pilocarpine nitrate at t = 0 and t = 6 hours. The antihypertensive effect of a single instillation of Glauplex 2 was shown to be approximately equivalent to that of two instillations of 2.6 p. cent pilocarpine nitrate.

Although there exists a number of different instrumental arrangements for obtaining useful O, N, and C K emission data, high resolution-photon excitation of substances appears to be a particularly promising method for studying the valence electronic structures of molecules containing the above elements. The interest in this study is the electronic structure of carbon-oxygen bond in urea, some selected quinones and salts of carboxylic acids, and squaric acid. These substances represent a progression of complexity, namely, (1) urea has a single C=0 bond, (2) quinones have two C=0 bonds where the ortho vs. para problem is of interest, (3) a carboxolate anion has two O atoms on a single C, and the interest is in distinguishing between mono and polycarboxylate ions as well as seeing evidence of quadruple bonding in Mo2(O2CCH3)4. These substances have received experimental and theoretical attention.

The general requirements of obtaining high resolution molecular X‐ray emission spectroscopy (0.01 to 0.1 eV) are inspected. Various X‐ray optics, sources, and detectors are reviewed in terms of intensity and resolution. An approximate theoretical formulation is offered to compare the speed of photograplhic detection with that obtained by scanning and position sensing photoelectric detection. The main features of the recently developed, automated scanning photoelectric attachment for a 5 M grating spectrometer are described. Experimentally obtained photographic and scanning photoelectric data for first order 0 K emission are compared.

A gas chromatographic procedure was developed to determine free and conjugated cis-3,3,5-trimethylcylcohexanol in plasma and urine. The sample is extracted with dichloromethane when free cis-3,3,5-trimethylcyclohexanol is determined, or with hexane after enzymatic hydrolysis, when conjugated cis-3,3,5-trimethylcyclohexanol is determined. An aliquot of the organic extract is injected into a stainless-steel column (packed with Carbowax 20M, 15% on Chromosorb W AW 100-120 mesh) and detected with a flame ionization detector. Extraction recovery from plasma and urine was almost 100% and the limit of quantification was fixed at 100 ng/ml plasma or urine. The procedure was evaluated in a pharmacokinetic study of cyclandelate and its metabolite cis-3,3,5-trimethylcyclohexanol.

The selectivity and binding potency of a series of alkyliminoxypropanolamines characterized by the lack of an aromatic nucleus are studied using a new non-selective radioligand, (-)-(125I)-Iodocyanopindolol. The relationship between the effectiveness in lowering the intraocular pressure (IOP) in experimental hypertensive rabbit eyes and their capacity to bind to ciliary processes beta 2-adrenoceptors is discussed. The inhibition constant (Ki) and beta 2/beta 1 ratios indicate a beta 2-selectivity for the tested drugs. Cyclopropyl, dicyclopropyl, cyclopentyl and cyclohexyl derivatives displayed a potent binding to ciliary processes beta 2-adrenoceptors and lowered the IOP about -18%. These compounds induced a lowering in IOP equal to that produced by timolol and appear to be effective and safe beta-adrenergic antagonists in open-angle glaucoma therapy. Decreasing the size of the alkyl group of the oxime, removing the oxime function or modifying the beta-hydroxyl group from the side chain led to a significant decrease in beta 2-adrenoceptor binding and induced weak hypotensive ocular activity. Since the tested alkyliminoxypropanolamine series has very similar physicochemical characteristics and therefore, ruled out the differences in their ability to reach, through the cornea, the targeted ciliary processes, it was demonstrated that contrary to generally held views, the action of the new beta-antagonist series on IOP is related to their ability to antagonize ocular beta 2-adrenoceptors.