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Condensates and natural gases are significant resources that frequently occur together in many petroleum systems. Unraveling their origins is crucial for effective petroleum exploration and exploitation. This is often a challenge because light crudes are volatile, deficient in biomarkers, and commonly altered. The origin of condensates and natural gases in the Upper-Cretaceous Almond Formation in southwestern Wyoming was unraveled through use of improved analytical and interpretative geochemical approaches constrained by regional geologic perspectives and basin modeling. Here, an improved GC–MS/MS method allowed simultaneous determination of saturate and aromatic biomarkers, diamondoids, and organo-sulfur compounds in the whole crudes. Furthermore, basin-specific calibration of diamondoid-based thermal maturity parameters, through correlation of measured indices for diamondoids in rock extracts versus measured reflectance of vitrinite from the same rocks, allowed reliable interpretation of maturity of the most likely source rocks. Modified interpretation schemes for C7-hydrocarbon distributions, and compositions of C1-C30 alkanes, aromatic and organosulfur compounds, and δ13C1-C5 together indicated that the condensate and natural gas from each well are likely co-generated and thermogenic products from non-marine source rocks, although methane is partially biogenic. The bulk thermogenic petroleum are too mature to have originated in the rocks adjacent to the producing reservoirs. The geochemical, geologic, and modeling interpretations collectively indicate that the condensates and associated natural gases were most likely generated, expelled, and migrated from the downdip, highly mature, near-shore/transitional humic source rocks of the Almond Formation/Mesaverde Group in the Washakie Basin and Great Divide Basin at >1.3% Ro and ∼30 Ma.

An improved GC–MS/MS method was developed for simultaneous determination of various types of molecular markers in whole crudes without the need for laborious group-type separation and discrete analyses of the diverse fractions. The ability to simultaneously identify and accurately quantify the numerous saturated and aromatic biomarkers, the organosulfur compounds (OSC) and the diamondoids in a single step was attained through use of expanded multiple reaction monitoring (MRM) transitions in specific time windows. The optimization was achieved through improving GC separation and selective choice of precursor and product ions, collision energies, dwell time, and time windows in the MRM settings. The method was tested using four crude oils of diverse types, densities and maturities: a heavy crude from Sicily (18° API), an intermediate-density crude from the Arabian Gulf (33° API), a light black oil from California (39° API), and a light condensate from Wyoming (53° API). The improvements were validated by checking accuracy and precision using three spiking levels of standard compounds into the oils. Comparison of the results of the single-step GC–MS/MS method with the results from traditional multi-step approaches indicates that the single-step GC–MS/MS approach achieved higher resolution, higher specificity and sensitivity, higher accuracy and precision for calculation of the common biomarker indices. Additionally, the single-step approach precluded the loss of light-end components during sample preparation and minimized co-elution problems in molecular analyses.

In a continuation of our initial investigation of the complex 13 C and 19 F spectra exhibited by two simple organofluorine compounds, additional organofluorine compounds expected to exhibit a wide range of spectral complexity were studied. Spectral simulations are critical for analyzing the more complex spin systems, in particular, A 3 B 3 X and A 6 B 3 X. Cross-correlated relaxation is commonly observed; examples of 13 C 19 F cross-correlated relaxation are shown with the signals for each nucleus exhibiting unequal relaxation rates. Higher order effects are particularly noticeable in the spectra of perfluoro- t -butyl alcohol because of a large 4 J FF value in the ( 13 CF 3 )( 12 CF 3 ) 2 12 COH isotopomer. The many additional transitions in an A 3 B 3 X spin system compared to an ABX spin system result in much more complex 19 F (A 3 and B 3 ) and 13 C (X) spectra, even though only three types of nuclei are involved in each spin system. The corresponding protio compounds typically constitute a much simpler A 3 M 3 X spin system because the long-range n J HH coupling ( n ⩾ 4) is much smaller than the corresponding long-range n J FF coupling. Spectra previously published for ethane-1- 13 C (A 3 B 3 X) and hexafluoroethane-1- 13 C (A 3 M 3 X) are notable exceptions and are discussed.

The CF(3) signals in the (13)C{(1)H} spectrum of 1,1,1,3,3,3-hexafluoroisopropyl alcohol and the (CF(3))(2) CH signals in the corresponding triflate exhibit much greater complexity than might first be expected. The same holds for the (13)C satellites in the (19)F spectra. Complex patterns appear because of higher order effects resulting from the combination of a relatively large four-bond (19)F-(19)F J coupling in the ((13)CF(3))(12)CH((12)CF(3))-containing isotopomer and a typical large one-bond (13)C/(12)C isotope effect on the (19)F chemical shift. This complexity cannot be eliminated at very high magnetic field strengths. The triflate (CF(3))(2)CH-O-SO(2)CF(3) presents still additional complexity because of the presence of two different types of CF(3) groups exhibiting (6)J(FF) in any of the isotopomers and the chemical shift differences in hertz between the various (19)F signals in the two different (13)CF(3)-containing isotopomers. In addition, the presence of a small (5)J(CF) in the ((13)CF(3))((12)CF(3))(12)CH-O-SO(2) (12)CF(3) isotopomer is revealed only through simulations. The hexafluoroisopropyl CF(3) groups in the alcohol and triflate and the SO(2)CF(3) group in the triflate apparently provide the first examples of cross-correlated relaxation in (13)CF(3) groups. An analysis of the spectra in the context of previously reported work highlights the novel aspects of our findings. In particular, for each part of the complex hexafluoroisopropyl CF(3) quartet, peak height and linewidth variations resulting from cross-correlated relaxation are observed. These variations within a group of (13)C signals reflect different spin-lattice and spin-spin relaxation rates for the transitions within that group arising from higher order coupling effects.

Hartree–Fock with and without MP2 (frozen core and full) corrections and density functional calculations have been performed on 1,2,3,6-tetrahydropyridine with basis sets 6-31G∗, 6-31+G∗ and 6-311+G∗∗. For all methods which included diffuse functions, the half-chair equatorial N–H conformer was found to be slightly more stable than the half-chair axial conformer, in agreement with experimental results. A detailed comparison for all the methods and basis sets was made with experimental data. These included rotational constants for both the normal and N–D isotopic species, dipole moments and dipole moment components. In addition, several interconversion pathways and barriers between the axial and equatorial conformations were explored by Hartree–Fock and B3LYP with the 6-31+G∗ basis set. The lowest energy pathway between was found to be via the N–H inversion (∼4–5 kcal/mol); via a bent (boat) axial form (∼6–7 kcal/mol) and finally via a bent (boat) equatorial form (∼7–8 kcal/mol). The planar form was found to be ∼10 kcal/mol less stable than the two half-chair forms.

Purpose The hypothesis for this prospective evaluation is that resorbable plates are equal to the performance of titanium 2-mm plates, regarding healing of the fracture with bone union and restoration of function. To prove this hypothesis, specific end points will be compared with literature norms for titanium 2-mm miniplate rigid fixation. The primary end point variable for this analysis is the union of the fracture and return to normal function. Secondary end point variables included the incidence of complications such as infection, malunion with malocclusion, soft tissue dehiscence, the need for revision surgery, specific technical challenges, operative time, and the learning curve for the surgeon. Patients and Methods This prospective study consisted of a sequential enrollment of 50 fractures that met the inclusion criteria of having a fracture of the mandibular body, symphysis, angle, or ramus, and required an open reduction and internal fixation for stabilization and repair. The resorbable plates and screws used consisted of an amorphous injection molded copolymer of L-lactide/D-lactide/trimethylene carbonate (Inion CPS system, Tampere, Finland). Data were collated and compared with literature norms for titanium plates and also compared with nonrigid fixation data from a prospective study performed on a similar population in the same institution. Results Clinical and radiographic evaluation indicated union of all fractures at the eighth follow-up visit. Three sites (6%) noted to have clinical signs of infection were treated immediately upon presentation, with fracture union by 8 weeks. There was no need for revision surgery in this series of patients; 12 screw heads fractured during screw placement and were immediately replaced without significant fracture sequelae. Conclusion Based on this limited series of patients, the hypothesis formulated for this study was validated.

Patient education and giving information is a core skill that improves patient adherence and medical outcomes.To evaluate the impact of a teaching intervention on 3rd-year students' competency in patient education and information giving about asthma medication delivery.Students (n=81) completed a 1-hr teaching intervention of didactics followed by role playing of asthma patient education scenarios. Using a standardized patient post intervention, patient education and information-giving skills about spacer/metered dose inhalers were scored overall and on a 12-item checklist and compared to a control group (n=70). Students' knowledge was evaluated using a short answer test.The performance of intervention students on overall patient education, 10 of the 12 checklist items, and the test was significantly higher than controls but did not approach competency.The 1-hr intervention improved clinical performance and knowledge, but students did not become competent. Future studies should investigate how competence in this and other core patient education skills can be successfully achieved.

1. Our understanding of psychological life has been underdeveloped and distorted because explanations have been created by only one half of the human species. The current broad and encompassing disease definition of codependency may devalue some of women's greatest strengths. 2. The disease model of codependency, it may be argued, is rooted in extant, reductionist models that suggest a developmental pathway of separation and individuation leading to an autonomous and independent maturity. 3. The feminist model of Growth in Connection proposes that the flowering of the self occurs within the development and maintenance of relationships in which accurate and mutual empathy is both the goal and the motivation toward growth.

The CF(3) signals in the (13)C{(1)H} spectrum of 1,1,1,3,3,3-hexafluoroisopropyl alcohol and the (CF(3))(2) CH signals in the corresponding triflate exhibit much greater complexity than might first be expected. The same holds for the (13)C satellites in the (19)F spectra. Complex patterns appear because of higher order effects resulting from the combination of a relatively large four-bond (19)F-(19)F J coupling in the ((13)CF(3))(12)CH((12)CF(3))-containing isotopomer and a typical large one-bond (13)C/(12)C isotope effect on the (19)F chemical shift. This complexity cannot be eliminated at very high magnetic field strengths. The triflate (CF(3))(2)CH-O-SO(2)CF(3) presents still additional complexity because of the presence of two different types of CF(3) groups exhibiting (6)J(FF) in any of the isotopomers and the chemical shift differences in hertz between the various (19)F signals in the two different (13)CF(3)-containing isotopomers. In addition, the presence of a small (5)J(CF) in the ((13)CF(3))((12)CF(3))(12)CH-O-SO(2) (12)CF(3) isotopomer is revealed only through simulations. The hexafluoroisopropyl CF(3) groups in the alcohol and triflate and the SO(2)CF(3) group in the triflate apparently provide the first examples of cross-correlated relaxation in (13)CF(3) groups. An analysis of the spectra in the context of previously reported work highlights the novel aspects of our findings. In particular, for each part of the complex hexafluoroisopropyl CF(3) quartet, peak height and linewidth variations resulting from cross-correlated relaxation are observed. These variations within a group of (13)C signals reflect different spin-lattice and spin-spin relaxation rates for the transitions within that group arising from higher order coupling effects.

In order to understand the unusual heat resistance of LamB protein (the outer membrane component of the maltose transport system in Escherichia coli and its receptor for bacteriophage lambda), we investigated the role of its 2 cysteinyl residues. Our studies show that Cys22 and Cys38 form an intrasubunit disulfide bond which contributes to the heat stability of the LamB protein trimer. Physical evidence for the disulfide was obtained by using site-directed mutagenesis to convert Asn36 to Met, which allowed cyanogen bromide cleavage between the 2 cysteines. Upon reduction one of the N36M fragments migrated as two pieces, resolved by two-dimensional polyacrylamide gel electrophoresis. Other mutagenized LamB proteins, in which 1 or both Cys residues were converted to Ser, exhibited a sharp loss of thermal stability. In contrast to wild-type LamB protein trimer, which does not dissociate to monomers even after 60 min at 100 degrees C, only 10-15% of the mutant LamB proteins remain trimeric after boiling 10 min. The disulfide bond in LamB protein is not required for its transport function, since both mutagenized LamB protein and N-ethylmaleimide-labeled LamB protein exhibit normal uptake of sugars in proteoliposomes. Finally, the disulfide bond must not be between subunits of the LamB trimer since reversible dissociation of trimer is achieved by low pH or denaturants in the absence of reducing agent.

This article describes the clinical and laboratory procedures for the construction of a surgical stent for prevention of restenosis after the surgical opening of posttraumatic synechia of the posterior part of the nasal cavum.

Recently, the ligand for c-mpl has been identified and cloned. Initial studies of this molecule indicate that it is the platelet regulatory factor, thrombopoietin (TPO). Previous work has indicated that c-mpl is expressed in very immature hematopoietic precursors and thus raised the possibility that TPO may act directly on the hematopoietic stem cell. Therefore, in these studies, we investigate the effects of TPO on hematopoietic stem cell populations isolated from the murine fetal liver and bone marrow. Cocultivation of stem cells with fetal liver stroma give rise to multilineage expansion of the stem cells but with little or no megakaryocytopoiesis. Addition of TPO to these cocultures gives significant megakaryocyte production. This production is enhanced in combination with Kit ligand or interleukin-3. The addition of TPO to stem cell suspension cultures produces a dynamic thrombopoietic system in which stem cells undergo differentiation to produce megakaryocytes and proplatelets. These experiments show that the megakaryocytopoietic and thrombopoietic activities of TPO are initiated at the level of an early progenitor cell or upon the hematopoietic stem cell.

An analysis of investigations related to positioning and skin care of the low-birth-weight infant, tempered with the authors' clinical experience, is presented. Protocols for positioning the low-birth-weight neonate and care of immature skin are provided. The nursing management plans are theoretically based and provide a foundation for testing the ability of nurses to improve developmental outcomes for this population of infants and reduce the cost of their care. A comprehensive reference list is provided.

In order to understand the unusual heat resistance of LamB protein (the outer membrane component of the maltose transport system in Escherichia coli and its receptor for bacteriophage lambda), we investigated the role of its 2 cysteinyl residues. Our studies show that Cys22 and Cys38 form an intrasubunit disulfide bond which contributes to the heat stability of the LamB protein trimer. Physical evidence for the disulfide was obtained by using site-directed mutagenesis to convert Asn36 to Met, which allowed cyanogen bromide cleavage between the 2 cysteines. Upon reduction one of the N36M fragments migrated as two pieces, resolved by two-dimensional polyacrylamide gel electrophoresis. Other mutagenized LamB proteins, in which 1 or both Cys residues were converted to Ser, exhibited a sharp loss of thermal stability. In contrast to wild-type LamB protein trimer, which does not dissociate to monomers even after 60 min at 100 degrees C, only 10-15% of the mutant LamB proteins remain trimeric after boiling 10 min. The disulfide bond in LamB protein is not required for its transport function, since both mutagenized LamB protein and N-ethylmaleimide-labeled LamB protein exhibit normal uptake of sugars in proteoliposomes. Finally, the disulfide bond must not be between subunits of the LamB trimer since reversible dissociation of trimer is achieved by low pH or denaturants in the absence of reducing agent.

The cytotoxic potential of interleukin 2 (IL-2) activated bone marrow (ABM) was compared with that of IL-2 activated peripheral blood lymphocytes (LAK cells) against three hematologic tumor cell lines (K-562, CEM, Daudi) and fresh lymphoid blasts in short-term chromium release assays. ABM was found to be superior to LAK cells against all tumor cells tested. The recovery of bone marrow (BM) cells dropped with passage of time in culture but their clonogenic potential was not impaired (with or without IL-2). BM contaminated with CEM cells and treated with IL-2 showed significant ability to purge itself of the leukemic cells in semisolid agar culture; the purging ability of 3- and 1-day ABM was comparable. IL-2 alone or BM alone had no influence on the growth of CEM cells. This study suggests that BM can be activated with IL-2 in vitro to generate the ability to eliminate contaminating leukemic cells without affecting its progenitor cell function in vitro.

A phase I trial of interleukin-2 and interferon gamma combination treatment in patients with advanced malignancies was performed based on preclinical in vitro and in vivo data which demonstrated synergistic antitumor effect. The toxicities, immune parameters, and tumor responses are described. The clinical and biologic maximal tolerated doses were extrapolated from these data.

A simple experiment involving deuterium exchange of the enolizable protons in ethyl acetoacetate followed by GC–MS has been developed. The principles demonstrated are the use of stable isotopes, keto–enol tautomerism, base catalysis, and the use of specific reagents to minimize or nullify side reactions. The changes in mass of specific fragment ions, as well as that of the molecular ions are indicative of the course of the reaction and illustrative of the fragmentation pathways. The acidity of the methylene hydrogens of the acetoacetate moiety is exploited in the acetoacetic ester synthesis of alkyl-substituted acetones. These readily exchange under very mild conditions. More challenging is to exchange all five enolizable hydrogens. Use of increasingly severe reaction conditions leads to side reactions, such as deuterolysis of the ester portion if D2O is used. The solution was to use ethanol O–d as the source of deuterium and KOD for the base for the exchange reaction and moderate heat. The role of ethano...

The purpose of this study was to assess the effectiveness of two different relaxation techniques in the management of postoperative pain. The sample consisted of 40 women between the ages of 21 and 65 years who were undergoing elective cholecystectomy. Using an experimental design, participants were randomly assigned to four groups: an experimental group who received a taped recording of a rhythmic breathing exercise (RB); an experimental group who received a taped recording of Benson's Relaxation Technique (BRT); an attention-distraction control group (CA) who received a taped recording of a history of the hospital; and a standard control (CB) group who had only the routine perioperative care which all groups received. Data were collected on postoperative sensation and distress at five time points during the first 72 postoperative hours, number of doses of analgesic medication during the same time period, and number of postoperative hospital days. Data were analysed using multivariate and univariate analyses of variance. The BRT group was significantly different from the CA group on a combined sensation and distress factor (P = 0.011). No significant differences were found among groups for doses of analgesics (P = 0.068) or postoperative hospital days (P = 0.56).

The low resolution spectra of φNCS and φNCO have been studied in the microwave R-band region. The spectroscopic constant ( B + C ) has been evaluated for both molecules. These data have been used to obtain information on the orientation of the linear NCS and NCO group relative to the bond from the phenyl ring. The results indicate an opening of the φ-N-C angle over that found in the hydrogen counterparts HNCS and HNCO. A modified INDO calculation yields structural parameters which are consistent with the trends observed, and indicate that the opening of the angle in going from HNCS (HNCO) to φNCS (φNCO) can be attributed to delocalization with the phenyl ring.

The infrared and Raman data on the ring-puckering vibration in cyclobutane and cyclobutane-d8 have been reexamined including the coordinate dependence of the reduced mass in the Hamiltonian. This was done for the purpose of estimating the importance of these small terms in the determination of barrier heights for four-membered rings and also on the determination of the dihedral angle corresponding to the potential minimum. The conclusions reached are that there is an isotopic dependence of the barriers to planarity in cyclobutane and cyclobutane-d8 yielding a difference of ∼14 cm−1, but the precise value of the difference in barrier heights is ill determined. The higher-order kinetic energy terms in the Hamiltonian can account for a spread of ∼3 cm−1 in each of the barriers derived for cyclobutane and cyclobutane-d8, depending on the details of the model used for the vibration, but not a difference of 14 cm−1, which undoubtedly indicates the effects of coupling with other vibrational modes. It is also found that the derived values of the dihedral angles are quite sensitive to the details of the vibrational model, in fact, much more so than to the uncertainties in the bond distances and bond angles. A relationship between the potential constants derived for cyclobutane and cyclobutane-d8 assuming an effective constant reduced mass and those derived for a semirigid model is demonstrated.

The potential of bone marrow transplantation as an immunotherapeutic modality, using biomodulation of the marrow cells has been ignored in autologous transplantation. Furthermore, many common cancers such as lung, colon, prostate, and pancreas are resistant to even transplant doses of conventional agents and hence require novel approaches such as biomodulation. This study shows that we can generate cytotoxic killer cells similar to lymphokine-activated killer cells capable of lysing NK-resistant tumor cells in vitro if we incubate human or murine bone marrow in IL-2. This was accomplished without affecting the ability of the bone marrow to fully reconstitute mice similar to that of fresh nonactivated bone marrow. Studies evaluating the IL-2 activated human bone marrow in vitro also indicated that these activated bone marrow have similar CFU to that of fresh human marrow. Furthermore, in murine in vivo studies, the activated bone marrow (ABM) caused significant tumor regression in tumor-bearing mice. Also, these ABM cells had similar or higher tumoricidal activity and longer kinetics than spleen lymphokine-activated killer cells in vitro. Also, the ABM had purging ability in vitro. Therefore this IL-2 ABM could be used as an active therapeutic tool and not just as a passive rescue element in the autologous bone marrow transplantation setting.

The microwave spectrum of 1,2-dimethylenecyclobutane has been studied in the range 26.5–40 GHz using a Hewlett-Packard 8400C Stark-modulated spectrometer. The rigid rotor constants have been derived for the ground state (in MHz: A = 4925.22, B = 4089.88, C = 2301.67) and four excited states of the ring-puckering vibration. That the ring skeleton is planar is indicated by the smooth variation of the rotational constants with vibrational state and by the value of 1/2(Ia + Ib − Ic) which is consistent with only 4 hydrogen atoms out of the plane of the remaining atoms. Analysis of the Stark effect yields a dipole moment lying along the b-axis; μb = 0.457 ± 0.002D. A physically reasonable set of structural parameters which reproduce the ground state rotational constants has been derived by adjustment of the carbon skeleton parameters by a diagnostic least-squares procedure.

The microwave spectrum of thietanone-3 has been studied in the R -band range (26.5–40.0 GHz) using a Hewlett-Packard Model 8400C phase stabilized Stark-modulated microwave spectrometer. The rotational constants in the ground state (in MHz: A = 10205.06 ± 0.59, B = 3266.63 ± 0.01, C = 2559.70 ± 0.01) and ten excited states of the ring-puckering vibration have been derived from fitting a -type low- J R -branch transitions. The rotational constants have been used in the determination of a single minimum anharmonic potential function for the ring-puckering vibration of the form V = a ( Z 4 + BZ 2 ) with a = 9.81, B = 6.41 where Z is a reduced ring-puckering coordinate. From the analysis of the Stark effect, the dipole moment has been determined in the ground vibrational state ( μ a = 0.999 ± 0.003D) and 5 excited states of the ring-puckering mode. This variation of the dipole moment is reproduced by the above potential function and the expansion μ v = 0.982 + 0.074〈 Z 2 〉 v , where 〈 Z 2 〉 v is the expectation value of Z 2 in the v th vibrational state. A model calculation to reproduce the variation of the rotational constants has been performed. There is some indication that the CCC (sp 2 ) and CSC ring angles decrease slightly as the ring puckers but the puckering is accomplished primarily by decreasing the CCS angles. A reasonable set of structural parameters which reproduce the ground state rotational constants has been derived by a diagnostic least-squares procedure.

Experiments to detemine the signs of the imaginary damping factors in the resonance denominators of the expressions for the third order susceptibilities governing coherent anti‐Stokes and coherent Stokes Raman spectroscopy (CARS and CSRS) have been carried out using the ν1 line of β‐carotene. The experimental results are compared to the two different theoretical results predicted by the fully quantum mechanical and the semiclassical calculations for the third order susceptibilities for CARS and CSRS.

Using Van Vleck perturbation theory, a relationship between two‐dimensional potential functions in ring‐puckering and ring‐twisting coordinates and effective one‐dimensional ring‐puckering coordinates is demonstrated. It is shown that effective one‐dimensional potential functions can be derived for 2,5‐dihydrofuran and s‐tetrazine which have essentially the same eigenvalue separations as the two‐dimensional potential functions previously derived. More useful is the fact that this procedure may be reversed and two‐dimensional potential surfaces have been derived for 1,4‐dioxadiene and cyclopentene. In mass weighted coordinates the potential function for dioxadiene is V (Q1,Q2) =28.49 Q14+24.00 Q12 +2555.2 Q22+294.6 Q12Q22, where V is in cm−1, Q in U1/2 A. Q1 is a mass weighted ring‐puckering coordinate and Q2 is a mass weighted ring‐twisting coordinate. The potential function for cyclopentene is V (Q1,Q2) =51.50 Q14−217.4 Q12+2262.4 Q22 −9.10 Q12Q22 yielding a barrier to planarity of 229 cm−1 essentially u...

An in vivo model has been designed to study the acute response of the microvascular system of exposed dental pulp to the topical application of isobutyl-2-cyanoacrylate. The results support the therapeutic use of isobutyl-2-cyanoacrylate as a pulp-capping agent, since it is well tolerated by the exposed pulp and does not induce an acute inflammatory response in the microvasculature.

The microwave spectrum of thiane, a heterocyclic analog of cyclohexane, has been studied in the region 26.5–40 GHz. The molecule is a highly asymmetric rotor (κ = 0.050154). From the analysis of both the a -type and c -type transitions, the rotational constants determined are (in MHz): A = 3992.719, B = 3005.812, and C = 1914.683. A study of the Stark effect has yielded the dipole moment components (in Debye units) μ a = 1.684 ± 0.009, μ c = 0.578 ± 0.002, which give a total dipole moment of μ = 1.781 ± 0.010. Comparison of the spectral data from tetrahydropyran, thiane, and 1,4-thioxane demonstrates the similarity in structure of these three compounds. It is found that a very reasonable set of structural parameters can be found which adequately fits the spectral data of all three molecules.

The microwave spectrum of 2-cycloheptene-1-one, an unsaturated cyclic ketone, has been studied in the regions 26.5–40 and 7.0–12.4 GHz. An analysis of the ground-state “ a ”-type transitions yielded the rotational constants (in MHz): A = 2997.27, B = 2049.24, C = 1399.76. The “ a ”-type transitions of an excited vibrational state were also assigned, giving A = 3000.51, B = 2046.65, C = 1398.88. The centrifugal distortion constants, D J and D JK , were needed to fit the data adequately. A study of the Stark effect yielded the dipole moment components (in debye) μ a = 3.63 ± 0.023 and μ c = 0.882 ± 0.040. The μ b component could not be determined from the Stark effect data. These data are used to discuss the molecular conformation of cycloheptene-1-one.

An in vivo model has been designed to study the acute response of exposed or unexposed dental pulp to the topical application of various biomaterials. This model permits sequential microscopic observations of the microvascular system of dental pulp before and after application of pulp capping agents, cementing agents, or cavity liners. The use of this experimental model provides useful information related to the tolerability of dental pulp to various biomaterials used in dentistry. Furthermore, this model serves as a useful supplement to more traditional long term methods for evaluating the biocompatability of dental materials.

The low resolution spectra of crotonyl chloride and crotyl alcohol have been studied in the microwave R-band region. The spectroscopic constant ( B + C ) has been evaluated for both molecules. These data have been used to obtain conformational information for these molecules.

19. Fusayama ‘r, Terachima S: DifTerentiatiob of two layers of carious dentin by staining. J Dent Res 51:866, 1972. Franc0 SJ, Kelsey WP: Caries removal with and without a disclosing solution of basic fuchsin. Oper Dent 6~46, 1981. Fusayama ‘T, Kurosaki N: Structure and removal of rarious dentin. Int Dent J 22:401, 1972. Ohgushi K. Fusayama T: Electron microscopic structure of the two layers of carious dentin. J Dent Res 54~1019, 1975. Sato Y. Fuaayama T: Removal of dentin by furhsin staining. J Dent Res 55:678, 1976. Shimizu C, Yamashita T, Fusayama T: Carious change of dentin observed on longspan ultrathin sections. J Dent Res 60~1826, 1981. Znnder H.\: Bacteria in the dentin after cavity preparation. Illinois Dent J 9:207, 1940. Seltzer S: The bacteriologic status of dentin after cavity preparation. J Am Dent Assoc 27:1799. 1940. Besic FC: The fate of bacteria sealed in dental cavities. J Dent Res 22~349, 1943. Schouboe ‘I‘, Macdonald JB: Prolonged viability of organisms sealed in dentinal caries. Arch Oral Biol 7:52S, 1962. Lrung RI,. Loesche WJCharbeneau GT: EHect of Dycal on bacteria in deep carious lesions. J Am Dent Assoc 100:193, 1980. King JB, (Irawtord JJ, Lindahl RL: Indirect pulp capping: A 20.

The microwave spectrum of 1,4-thioxane, a heterocyclic analogue of cyclohexane, has been studied in the region 26.5–40 GHz. The molecule is a highly asymmetric rotor ( k = −0.0740917). From the analysis of the a -type transitions, the rotational constants determined are (in MHz) A = 4333.85, B = 3076.14 and C = 1991.96. A study of the Stark effect has yielded the dipole moment components (in Debye units) μ a = 0.290 ± 0.003, gm c = 0.0537 ± 0.0004, which give a total dipole moment of μ = 0.295 ± 0.003. These data are consistent with a chair conformation for the ring.

Under certain conditions, when the laser pump frequency approaches an electronic transition frequency, negative peaks have been observed in coherent anti‐Stokes Raman spectra. Two conflicting explanations of this phenomenon have been offered. We have noted that these two explanations lead to a different dependence of the intensity of the negative peaks on the power in the pump beam. We have experimentally determined this power dependence in the case of a 5×10−3M solution of N, N‐diethyl‐p‐nitrosoaniline in benzene and found that the intensity of the negative peaks varies with the square of the power in the pump beam. This result is consistent with the explanation that the negative peaks arise from a cross term between the background susceptibility and the imaginary part of the Raman susceptibility and not from the inverse Raman effect.