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The deposition of diamond, a metastable crystalline form of carbon, from low pressure gases poses intriguing questions about the mechanisms of growth. Tunable IR Diode Laser Absorption Spectroscopy, Laser Multi-Photon Ionization Spectroscopy, and Laser Induced Fluorescence were used to characterize the gaseous environment in the Chemical Vapor Deposition growth of diamond films. The quality of the deposited material was examined by optical and SEM microscopies, and Raman, Auger, and XPS spectroscopies. When a reactant mixture of 0.5% methane in hydrogen, was passed across a hot Tungsten filament (2000 C), C2H2, C2H4, H and CH3 were detected above the growing diamond surface, and concentration limits for undetected species were determined. These results are discussed in terms of simple models for species formation and consumption, as well as the implications for the diamond growth mechanism.

The use of in‐situ, optical diagnostics for probing the gaseous chemistry in the chemical vapor deposition (CVD) of diamond is described. Both radical (H, CH3) and stable (CH4, C2H2, C2H4) species have been detected. We report here the resonance‐enhanced multiphoton ionization (REMPI) detection of CH3 and atomic hydrogen under diamond CVD conditions. The H atom concentration, found to be quite sensitive to initial CH4/H2 fraction (F0), decreased with increasing F0 and was severely depleted with F0=30% and filament temperatures below 2200 C. Our present model of the filament‐assisted gas phase environment is one in which thermodynamically‐favored species (e.g., C2H2, CH3) are formed at high temperature near the filament, followed by depletion of the more reactive species during transport to the diamond growth surface. An interference effect due to third harmonic generation in atomic hydrogen was also observed in the REMPI experiments.

If the basis set of atomic orbitals for the >C = 0 group is restricted to the two 2pπAO′s xc and xo, which lie perpendicular to the sp2 hybridization plane defined on the carbon center, and to the non-bonding AO of oxygen, no, which lies in the hybridization plane and is perpendicular to the C = 0 axis, it is not difficult to show that the ionization potential of the π-electron is related to the energy of the π* ← π transition by2 $$ {{\rm{I}}_\pi } = {\rm{ 0}}{\rm{.5h}}{\nu _{\pi \pi }}*{\rm{ - K}}\left( {{\alpha _{\rm{c}}}{\rm{ + }}{\alpha _{\rm{o}}}} \right)/2. $$ (.....1) No simple relation between the ionization potential of the n-electron and the energy of the π* ← n transition is formulable; however, Iπ and h nπ* can be connected via $$ {{\rm{I}}_\pi } = {\rm{ h}}{\nu _{{\rm{n}}\pi }}*{\rm{ - }}\left( {3/2} \right){\rm{K}}{\alpha _{\rm{c}}}, $$ (.....2) where αc and αo are Coulomb integrals for 2pπ electrons on carbon and oxygen, respectively, and K is a scaling factor. Granted the constancy of αc and αo throughout a series of carbonyl-containing molecules, it follows that Eqs. 1 and 2 define very simple linearities which are subject to experimental test.

Cellulase from Aspergillus niger, (a-amylase from Bacillus sp. and protease from Bacillus globigii were used as enzyme sources in this study to examine how their respective substrates protect them in two kinds of simulated gastrointestinal tract digesting processes. Avian total digest tract simulation test showed that filter paper, Avicel and cellulose resulted in 7.7, 6.4 and 7.4 times more activity than of unprotected cellulose, respectively. Protease with addition of casein, gelatin or soybean protein showed no significant protection response. Starch protected amylase to be 2.5 times activity of the unprotected one. Monogastric animal total tract digestion simulation test showed that filter paper, Avicel and cellulose resulted in 5.9, 9.0 and 8.8 times activity of unprotected cellulase, respectively. Casein, gelatin and soybean protein resulted in 1.2, 1.3 and 2.0 times activity of unprotected protease, respectively. Starch did not protect amylase activity in monogastric animal total tract simulation. Protection of mixed enzymes by substrates in two animal total tract simulation tests showed that filter paper in combination with soybean protein resulted in 1.5 times activity of unprotected cellulose, but all substrates tested showed no significant protection effect to protease. Soybean protein and starch added at the same time protected the amylase activity to be two times of the unprotected one. Test of non-purified substrate protection in two animal total digest tract simulation showed that cellulase activity increased as BSA (bovine serum albumin) concentration increased, with the highest activity to be 1.3 times of unprotected enzyme. However, BSA showed no significant protection effect to protease. Amylase activity increased to 1.5 times as BSA added more than 1.5% (w/v). Cellulase activity increased to 1.5 times as soybean hull was added higher than 1.5%. Amylase had a significant protection response only when soybean hull added up to 2%. Protease activity was not protected by soybean hull to any significant extent.

Background/aims: Treponema denticola outer membrane proteins are postulated to have key roles in microbe–host interactions in periodontitis. Because there are no reports of in vivo expression of these putative virulence factors, we examined several T. denticola strains to determine whether sera from human subjects recognized specific T. denticola outer membrane proteins. Methods: Soluble extracts were prepared from exponential phase cultures of T. denticola strains representing three serotypes, from defined T. denticola mutants defective in Msp (major surface protein) or PrtP lipoprotein protease complex (CTLP; dentilisin), and Escherichia coli strains expressing distinctly different T. denticola Msp. Extracts were subjected to Western immunoassays using archived human serum samples. Results: Human serum antibodies (immunoglobulin G class) recognized multiple protein bands in T. denticola strains. In the parent strain ATCC 35405, these included bands at 72-, 53-, 40-, and 30-kDa. Bands corresponding to Msp and the PrtP protease complex proteins were absent in isogenic msp and protease complex mutants, respectively. Individual human sera showed specificity for one or more Msp types. Conclusions: This is the first definitive report of human serum antibody responses to specific T. denticola antigens. T. denticola Msp and the proteins comprising the PrtP lipoprotein protease complex are expressed in vivo and are immunogenic in humans. Human antibody recognition of Msp exhibits strain specificity and is consistent with strain serotyping. These results demonstrate the utility of T. denticola isogenic mutants in characterizing host immune responses to periodontal pathogens.

The optical absorption spectra of H2O and D2O are reported at various pressures for 2000?λ?950 A. The 1670 A band is vibrationally structured (ν2 bend) and the excited 1B1 state contains a considerable intravalence 4a1 component. The 1280 A state 3sa1; 1A1 is linear and dominantly Rydberg. A Renner–Teller analysis of the 1280 A band leads to detection of a perturbing state at 1365 A which may be assigned as a bent, heavily Rydberg 3sa1; 1B1 state. A reanalysis of K‐shell excitation spectra bolsters this 3sa1; 1B1 assignment. Isotope shift studies in the 1130–980 A region lead to some vibronic reassignments. The terminal state of the 968 A absorption band is a linear 5sa1; 1A1 state. In sum, a total of 21 electronic states, comprising fragments of six Rydberg series, have been assigned.

The time dependences of the 2.2 MeV and 0.51 MeV gamma ray lines from solar flares are calculated and the results are compared with observations of the 1972, August 4 and 7 flares. Time lag between the nuclear reactions and the formation of these two lines are caused, respectively, by capture of the neutrons, and by deceleration of the positrons and decay of the radioactive nuclei. Results show that the calculation is consistent with the observed rise of the 2.2 MeV line on August 4, and it does not require different time dependences for the accelerated protons and electrons in the flare region. The above lags can explain the delayed gamma ray emission observed on August 7. Positrons of energies greater than about 10 MeV could be detected in interplanetary space following large solar flares.