PubMed Health⌕ Search

Biomedical subjects

H Bürger

Publications and source records attributed to H Bürger.

At least 55 records · Page 3Linked to original sources
PubMed1999

The Coriolis-Coupled States v7 = 1 and v9 = 1 of trans-HCOOD and trans-DCOOD.

The Fourier transform gas-phase infrared spectra of the two lowest Coriolis-perturbed nu7 and nu9 bands of deuterated formic acid HCOOD and DCOOD have been measured with a resolution of ca. 0.003 cm-1. Combined analysis of the assigned IR transitions and all the available rotational data have allowed the determination of the band centers, rotational and centrifugal distortion parameters, and Coriolis coupling terms. Standard deviations of the IR transitions are 0.000246 cm-1 for HCOOD and 0.000209 cm-1 for DCOOD. Determined band centers are nu0(nu7) = 558.2723 cm-1, nu0(nu9) = 508.1321 cm-1 for HCOOD and nu0(nu7) = 554.4397 cm-1, nu0(nu9) = 492.2254 cm-1 for DCOOD. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

High-Resolution Infrared Spectrum of nu5, nu4, nu3, nu4 + nu5, and 2nu4 Band Systems of Deuterobromoacetylene.

High-resolution vibration-rotation spectra of gas-phase deuterobromoacetylene have been recorded in the 240-990 cm-1 infrared region. The analyzed band systems are rich in hot bands and have a high density of lines. Five band systems and a total of 124 vibration-rotation bands of the isotopic species DCC79Br and DCC81Br have been rotationally analyzed. Accurate rotational parameters and vibrational wavenumbers for 33 vibrational states of each species have been obtained from the rotational analysis. l doubling and rotational l resonance have been observed on some states and the respective resonance parameters have been obtained through nonlinear least-squares optimization. A Fermi resonance block model with perturbation terms has been used for the analysis of the vibrational states. With optimized parameters, the model produces root-mean-square deviations of observed - calculated wavenumbers of about 0.3 cm-1 for both isotopic species. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

The Interacting v6 = 2 Levels of D3Si35Cl: A Tool to Determine Ground State Constants from High-Resolution Spectra in the 440-590 and 900-1100 cm-1 Regions.

High-resolution FTIR spectra of monoisotopic D3Si35Cl have been recorded in the regions 440-590 cm-1 (nu3/nu6) and 900-1100 cm-1 (2nu6/nu3 + nu6/2nu3). A detailed rovibrational study was done for the 2nu06, 2nu-/+26, and 2nu3 overtone bands and for the 2nu+/-26-nu+/-16, 2nu06-nu-/+16, and (nu3 + nu+/-16)-nu+/-16 hot bands. For the first time the interactions occurring between the v6 = 2, v3 = v6 = 1, and v3 = 2 levels of any trideuterated silyl halide have been analyzed. The (nu3 + nu+/-16)-nu+/-16 hot band served to obtain accurate energies of the v3 = v6 = 1 level, the nu3 + nu6 combination band not being detectable on our spectra. The first experimental determination of A0 and D0K for this molecule was undertaken by a well-established method, using the nu6, 2nu+/-26-nu+/-16, and 2nu-/+26 bands. Ground state energy differences DeltaK(J) = E0(J, K) - E0(J, K - 3) were calculated for K values from 2 to 16. By a least-squares fit of 163 such differences, the A0 and D0K values thus obtained were (in cm-1): A0 = 1.4278230(8) and D0K = 5.3916(31) x 10(-6). Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

High-Resolution Infrared Spectra and Simultaneous Rovibrational Analysis of the nu2, nu3, nu5, and nu6 Bands of H3SiF.

A high-resolution FT infrared spectrum of H3SiF (resolution 0.0024 cm-1) in the region 620-1130 cm-1 was measured and used to analyze the fundamental bands nu2 (A1), 990.851 cm-1; nu3 (A1), 875.011 cm-1; nu5 (E), 962.213 cm-1; and nu6 (E), 729.528 cm-1. A total number of 7241 transition wavenumbers (including 53 perturbation-allowed transitions) with J' </= 49 have been fitted by taking into account various Coriolis interactions, alpha-resonance terms, and l-type interactions between and within the vibrational levels v2 = 1, v3 = 1, v5 = 1, and v6 = 1. The strongest interaction in this system of levels is the x-y Coriolis coupling between the v2 = 1 and v5 = 1 vibrational states. However, it turns out that the x-y and z-type Coriolis interactions also have to be introduced explicitly between the v5 = 1 and v6 = 1 states as well as the x-y Coriolis interactions between v3 = 1 and v5 = 1, and v3 = 1 and v6 = 1 states, in order to fit the data quantitatively. The standard deviation of the fit was varsigma = 8.6 x 10(-5) cm-1 for 7241 transition wavenumbers and 68 fitted parameters. The sign relations between the fitted parameters and the possibility of fitting the parameters in different schemes are discussed. The results have been used to find close coincidences between the frequencies of the CO2 laser lines and the transition wavenumbers of the nu2 and nu5 bands of H3SiF for the main natural isotopomer. We report integrated absorption band strengths which are important for infrared laser chemistry. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

Mid- and Near-Infrared Spectra, Millimeterwave Spectra, and Global Analysis of (16)O(12)C(80)Se.

We have recorded a total of 12 FTIR spectra of monoisotopic OC(80)Se in different spectral regions with a resolution (1/maximum optical path difference) between 2.7 and 13.2 x 10(-3) cm(-1). These spectra spanned the range from 350 to 7800 cm(-1), many bands being studied with different p x L products in order to also detect weak hot bands. Altogether 18 band systems comprising 81 different bands, mostly of Sigma type, were observed and analyzed by means of polynomial expansions in J(J + 1). New rotational transitions of vibrationally excited states as high as 2200 cm(-1) with J" 17-25 in the 140-210 GHz and J" 53-58 in the 430-470 GHz millimeterwave regions were measured with the assistance of predictions by the global fit. This fit was performed using a weighted least-squares procedure and employing the whole body of data, and about 100 molecular parameters were determined that describe the energy level of (16)O(12)C(80)Se with statistical accuracy. Improved highly accurate ground state parameters up to sextic centrifugal distortion terms were obtained by a merge of ground state combination differences and pure rotational data. The v(1), v(2), v(3) polyad interacts anharmonically with the v(1) - 1, v(2) + p, v(3) + q polyads with p + 2q = 4. Moreover, some local crossings with Coriolis interactions between (v(1), v(2), v(3)) and (v(1) - 1, v(2) + 3, v(3) + 1) levels were observed and treated perturbationally. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

Radio-Frequency, Centimeter-Wave, Millimeter-Wave, and Infrared Spectra of SiDF(3) in the v(6) = 1 Excited State.

This paper deals with the first study of high-resolution radio-frequency, centimeter-wave, millimeter-wave, and infrared spectra of the deuterated isotopomer of trifluorosilane, SiDF(3), in its lowest degenerate excited v(6) = 1 state. Following the work of E. I. Lobodenko, O. N. Sulakshina, V. I. Perevalov, and Vl. G. Tyuterev, (J. Mol. Spectrosc. 126, 159-170 (1987)) and Harder (J. Mol. Spectrosc. 194, 145 (1999)), the data (18 A(1)-A(2) transitions, 229 l-type resonance transitions, 189 pure rotational transitions, and 1167 rovibrational transitions) have been fitted using three equivalent Q, D, and QD reduction schemes enabling the fit of one of the three interaction parameters d, q(12), and epsilon, respectively, while the other two are fixed to zero. In addition to further higher order constants, either f(K)(22) or tau(K) also had to be constrained. By checking the standard deviation of each data set and the relations between parameters determined within different constrains, the six reduction schemes have been shown to be unitary equivalent. Furthermore, the axial rotational ground state constant C(0) has been accurately determined. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

H(3)Si(37)Cl Revisited with High Resolution: The Ground State and the v(2) = 1; v(3) = 1, 2, and 3; v(5) = 1; v(6) = 1 and 2; and v(3) = v(6) = 1 States.

The infrared spectrum in the range 400-1600 cm(-1) of isotopically pure H(3)Si(37)Cl has been recorded at high resolution (2.4-6.6 x 10(-3) cm(-1)) and analyzed. Fifteen bands have been studied, namely the four fundamentals nu(3) (543.968 cm(-1)), nu(6) (663.738 cm(-1)), nu(2) (947.982 cm(-1)), and nu(5) (950.657 cm(-1)), the overtone bands 2nu(3), 2nu(0)(6), and 2nu(-/+2)(6), the combination band nu(3) + nu(6), and seven hot bands. Improved ground state constant parameters have been obtained, including all four sextic distortion constants. As for the J-independent parameters A(0), D(0)(K), and H(0)(K), they were determined mainly through the "loop method" involving nu(6), 2nu(-/+2)(6), and 2nu(-/+2)(6)-nu(+/-1)(6) and checked through the strong interactions between nu(2) and nu(5), producing some "forbidden lines." The nu(2)/nu(5) dyad was fitted with success using two different reduced Hamiltonians. Concerning nu(3) and nu(6), in spite of their relatively large separation, a Coriolis interaction could be evidenced. In both nu(2)/nu(5) and nu(3)/nu(6) interacting systems the sign of the interaction was found positive. As for the overtones, 2nu(3) was treated as isolated and 2nu(0)(6) and 2nu(-/+2)(6) as linked together by an l(2, 2) interaction. The data on the v(3) = v(6) = 1 levels were obtained mainly from the two hot bands nu(3) + nu(6) - nu(3) and nu(3) + nu(6) - nu(6), and marginally from the weak band nu(3) + nu(6), and also fitted as for an isolated level. A weak x,y-Coriolis interaction with level crossing between K/(kl - 1) = 21 and 22, and a local l(1, -2) resonance at K = 13/kl = -15 between 2nu(3) and nu(5) were furthermore detected. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

The Ground State of D(2)Se and HDSe.

Ground state rotational constants of D(M)(2)Se and HD(M)Se, M = 76, 77, 78, 80, and 82, have been determined up to octic centrifugal distortion terms from ground state combination differences. These were obtained from rotational analyses of the nu(2), nu(1), and nu(3) bands both of natural and (80)Se monoisotopic material recorded with a resolution of ca. 3 x 10(-3) cm(-1). While the full set of rotational parameters of the (80)Se species was determined with significance, some of the centrifugal distortion terms of the less abundant species were either constrained to those of the (80)Se species or extrapolated. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

Isotope Substitution in Near Local Mode H(2)X Molecules: The nu(1) and nu(3) Bands of D(2)Se.

The high-resolution (0.0027 cm(-1)) Fourier transform spectra of the D(2)Se molecule as (80)Se monoisotopic and natural material were recorded for the first time in the 1500-1900 cm(-1) region where the nu(1) and nu(3) vibration-rotation bands are located. Because accurate information about the rotational structures of different vibrational states was still lacking, the isotopic relations between rotational, centrifugal distortion, resonance interaction, etc., parameters of the H(2)Se and D(2)Se species were derived and successfully used for the construction of a synthetic spectrum for the nu(1) and nu(3) bands. As a result, lines of the recorded spectrum were assigned, and band centers, rotational, centrifugal distortion, and resonance interaction parameters for the (100) and (001) states of the species D(2)(M)Se, M = 76, 77, 78, 80, and 82, were determined. The obtained sets of parameters reproduce values of the vibration-rotation energies with a "mean" accuracy of 0.00007 cm(-1) for the D(2)(80)Se, and a slightly worse accuracy for other Se isotopic species. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

High-Resolution FTIR and Millimeter-Wave Study of D(3)SiF: The Ground, v(3) = 1, and v(6) = 1 and 2 States.

The nu(6) (555.453 cm(-1)), the nu(3) (888.899 cm(-1)), and the very weak 2nu(6) infrared bands (2nu(-/+2)(6) 1101.734 cm(-1), 2nu(0)(6) 1100.102 cm(-1)) for the (28)Si species of D(3)SiF have been recorded with a resolution of 3.3, 2.4, and 5.0 x 10(-3) cm(-1), respectively. Millimeter-wave spectra up to 640 GHz of D(3)SiF in the ground, v(3) = 1, and v(6) = 1 and 2 states were measured. Ground state constants complete up to H constants including the K-dependent parameters A(0), D(0)(K), and H(0)(K) as obtained by the nu(+/-1)(6)/2nu(+/-2)(6)-nu(+/-1)(6)/2nu(-/+2)(6) loop method were determined by a merge of 2388 ground state combination differences with 59 rotational data. The v(3) = 1 and v(6) = 1 and 2 levels appear to be unperturbed intervibrationally for the J and K values that could be accessed. However, Deltal = Deltak = +/-2 and Deltal = +/-2, Deltak = -/+4 interactions affect the v(6) = 1 level while the v(6) = 2 levels undergo three interactions of Deltal = Deltak = +/-2, Deltal = +/-2, Deltak = -/+1 and Deltal = +/-4, Deltak = -/+2 type. Typically, for the different bands, 2000-4000 pieces of infrared data augmented by 36-120 rotational data were fitted together. Owing to the weakness of the 2nu(6) band, the body of v(6) = 2 data was enlarged by energies that are deduced from the 2nu(6)-nu(6) and nu(6) bands and which span in particular high K values. Comparison with available ab initio data derived from the harmonic and anharmonic force fields is made. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

Analysis of Rotational and Rovibrational Spectra of SiDF(3) in the Ground and v(4) = 1 Excited States.

This paper presents the analysis of the spectra of SiDF(3) in its vibrational ground and v(4) = 1 states. The pure rotational spectrum of the ground state was measured up to 903 GHz (J" = 65). Rotational, quartic, and sextic centrifugal distortion constants were accurately determined. Furthermore the parameter ||h(3) || = 7.64(11) x 10(-4) Hz was derived from the observation of A(1)-A(2) splittings of six K = 3 lines. The assignment of the v(4) = 1 spectrum was performed by combining 140 pure rotational frequencies and more than 2300 rovibrational transitions. Among them, because of the strong (+/-2, -/+4) interaction, there are more than 90 A(1)-A(2) resolved split transitions between the (l = 0, k = +/-3) ground state levels and the (l = +/-2, k = -/+1) v(4) = 1 levels. Although the v(4) band is located at about 994.3 cm(-1), the energies of the other fundamental bands are at a distance of more than 140 cm(-1). The assumption of the isolated character of the state was confirmed by the small differences between the v(4) = 1 state and the ground state parameters and by the possibility of using the D and Q reduction schemes proposed by E. I. Lobodenko, O. N. Sulakshina, V. I. Perevalov, and Vl. G. Tyuterev [J. Mol. Spectrosc. 126, 159-170 (1987)]. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

Isotope Substitution in Near Local-Mode H(2)X Molecules: Stretching Fundamental Bands of HDSe.

The high-resolution FTIR spectrum of the HDSe molecule in the presence of H(2)Se and D(2)Se was recorded on (80)Se monoisotopic and natural samples in the 1500-2900 cm(-1) region and theoretically analyzed in the regions of the stretching fundamental bands nu(1) and nu(3) near 1692 and 2351 cm(-1), respectively. The analysis was performed starting from derived isotopic relations between vibration-rotation, anharmonic, centrifugal distortion, and other parameters which reveal high predictive power. Strong resonance interactions between the states (100) and (020) are taken into account, and sets of parameters which reproduce the experimental rotation-vibration energies of the (100) and (001) states with a mean accuracy of 0.00008 and 0.00009 cm(-1), respectively, for the HD(80)Se species, were obtained. For the less abundant species, for which some higher order terms were constrained, slightly worse agreement was achieved. The refined spectroscopic parameters are very close to their predicted values. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

High-Resolution IR Spectrum of SCF(2) from 1000 to 1400 cm(-1): The nu(1)/nu(3) + 2nu(5)/nu(2) + nu(3) and nu(4)/nu(2) + nu(5) Interacting States.

The infrared spectrum of SCF(2) was recorded in the 1000-1400 cm(-1) region with a resolution of 2.5 x 10(-3) cm(-1). The rotationally resolved nu(1) and nu(4) band systems were studied for the first time, and altogether 11 500 transitions were assigned. Both fundamentals are involved in strong anharmonic (Fermi) resonances. Effective centers (J = K(a) = K(c) = 0) of the interacting bands are nu(1) 1366.7117 cm(-1), nu(3) + 2nu(5) 1365.4257 cm(-1), nu(2) + nu(3) 1311.1491 cm(-1) (a(1) species), and nu(4) 1190.0839 cm(-1), nu(2) + nu(5) 1217.8191 cm(-1) (b(1) species). The strong K(a) dependence of the nu(1)/nu(3) + 2nu(5) level mixing enabled a numerical determination of the interaction constants while the other anharmonic interactions were accounted for by consideration of relative intensities. Deperturbed band centers, anharmonicity constants, and equilibrium and excited state rotational and centrifugal distortion constants were determined. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

The nu(2) Bands of the Deuterated Species D(2)Se and HDSe.

For the first time D(2)Se and HDSe as (80)Se monoisotopic and natural material were studied in the region of the nu(2) fundamental vibration by high-resolution (0.0033 cm(-1)) Fourier transform infrared spectroscopy. For D(2)Se which is an asymmetric rotor with C(2v) symmetry the nu(2) band is of B type while for HDSe (C(s) symmetry) it is a hybrid band, and both A- and B-type transitions were observed. Depending on the isotopic abundances, 300-1000 lines were assigned for each of the isotopic (M)Se species (M = 76, 77, 78, 80, and 82). The corresponding (010) experimental rotational levels, obtained by adding the observed line positions to the ground state levels derived from J.-M. Flaud, Ph. Arcas, O. N. Ulenikov, G. A. Onopenko, N. E. Tyabaeva, W. Jerzembeck, and H. Bürger, (J. Mol. Spectrosc., in press) were fitted satisfactorily using a Watson-type Hamiltonian in A reduction and I(r)-representation: the rms deviations are ranging from 1.5 to 4.3 x 10(-4) cm(-1) depending on the isotopic species. Hamiltonian constants up to high order (octic terms) were determined for each isotopic species. For the most abundant Se isotopic species, namely (80)Se, the band centers are nu(0) (D(2)(80)Se) = 741.67503 cm(-1) and nu(0) (HD(80)Se) = 900.43820 cm(-1). Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

Telomerase is a highly sensitive and specific molecular marker in fine-needle aspirates of breast lesions.

PURPOSE: Telomerase has been detected in a majority of human malignant tumors, making telomerase activity (TA) one key difference between mortal and immortal cells. In this study, we evaluated in blind-trial fashion the association of TA with cytologic and final clinical/pathologic diagnosis in fine-needle aspirates (FNAs) of breast lesions. MATERIALS AND METHODS: In 172 FNAs, including 80 samples that were cytologically malignant, 18 that were atypical but not diagnostic for malignancy, and 74 that were cytologically benign, TA was determined by a modified nonradioactive telomeric repeat amplification protocol (TRAP) assay. Final diagnosis was made by pathologic examination of follow-up surgical material available for all the cytologically malignant samples, a majority of the cytologically atypical samples, and a portion of the cytologically benign samples. RESULTS: TA was detected in 85 of 172 samples. Comparison of the cytologic and histologic diagnoses with TA showed that 80 of 87 samples from patients with breast cancer were telomerase-positive, resulting in a sensitivity of 92%. TA was found in four of five FNAs from carcinomas that were considered cytologically atypical but not diagnostic for malignancy. Eighty of 85 samples from patients with benign breast lesions were telomerase-negative, revealing a specificity of 94%. The five positive cases in this group were all fibroadenomas with low TA. Among the 18 cases with a cytologic diagnosis of atypia, there was a strong positive relationship between TRAP findings and histologic diagnosis. CONCLUSION: The detection of TA in FNAs of breast lesions is a highly sensitive and specific marker of malignancy and may be used as an adjunct in cases with an equivocal cytologic diagnosis.

Biomarkers, Tumor↗
PubMed1998

Chromosomal aberrations associated with invasion in papillary superficial bladder cancer.

Non-invasive and invasive papillary transitional cell carcinomas of stages pTa and pT1 represent the first steps of tumour progression in bladder cancer. In order to analyse different chromosomal alterations of pTa and pT1 superficial bladder cancer, 46 tumour specimens were examined by comparative genomic hybridization (CGH). Losses of chromosome 9 material (11/20) and gains of chromosome 17 material (6/20) were frequently found in pTa tumours. Stage pT1 tumours were characterized by gains of chromosome 1q (14/26; including amplification at 1q21-q24 in three cases) and chromosome 17 material (15/26), as well as by losses of 11p (15/26) and 11q (13/26). Other loci frequently showing losses in pT1 tumours were 2q (9/26), 4q (10/26), 5q (9/26), 8p (10/26), 9p (9/26), 9q (12/26), 10q (8/26), 17p (7/26), and 18q (8/26). Amplifications were detected at 8q21/22, 5q21, 7q36, 10p14, 10p12, 10q25, 12q12, and 12q14. The most striking differences between grade 2 pTa and pT1 tumours were gains of 1q (P < 0.01) and losses at 2q (P < 0.025), 10q (P < 0.05), 11p (P < 0.01), 11q (P < 0.01), and 17p (P < 0.05), as well as the total number of aberrations (pTa grade 2: 4.1; pT1 grade 2: 8.6 aberrations per tumour). These data show characteristic chromosomal aberrations associated with invasion in superficial bladder cancer.

Carcinoma, Transitional Cell↗
PubMed1998

The First Si-H Stretching Overtone of H3SiD: Emergence of Local Mode Effects

The FTIR spectrum of H3SiD in the 4100-4500-cm-1 region was recorded at Doppler-limited resolution, and four bands were studied. At lower wavenumbers, two strong bands, which in the local mode picture can be assigned to (200, E) (nu0 = 4308.5667 cm-1) and (200, A1) (nu0 = 4307.8441 cm-1), were analyzed, and at higher wavenumbers, two weaker bands, namely (110, E) at 4378.1950 cm-1 and (110, A1) at 4375.9763 cm-1, were analyzed. A total number of approximately 1900 lines in the strong dyad and 1000 lines in the weak one were assigned and fitted with standard deviations of the residuals approximately 0.0008 cm-1. The strong system (200) is close to local mode behavior, with no x, y Coriolis term needed and only a small z Coriolis term, and simple arithmetic relations between vibration-rotation parameters are fulfilled as expected. The local mode behavior of the weak system (110) is less pronounced, but z and x, y Coriolis effects are smaller than in the Si-H stretching fundamentals. Comparison of computed and observed spectra provided a good estimate for the ratios of transition moments of the different bands: they are, in absolute value, proportional to 3.5:1.75:1:1 for (200, E), (200, A1), (110, E), and (110, A1), respectively. Copyright 1998 Academic Press.

Journal Article↗