Continuous centrifuge decelerator for polar molecules.

Producing large samples of slow molecules from thermal-velocity ensembles is a formidable challenge. Here we employ a centrifugal force to produce a continuous molecular beam with a high flux at near-zero velocities. We demonstrate deceleration of three electrically guided molecular species, CH3F, CF3H, and CF3CCH, with input velocities of up to 200 m s(-1) to obtain beams with velocities below 15 m s(-1) and intensities of several 10(9) mm(-2) s(-1). The centrifuge decelerator is easy to operate and can, in principle, slow down any guidable particle. It has the potential to become a standard technique for continuous deceleration of molecules.

High-resolution mass-selective UV spectroscopy of pseudoephedrine: evidence for conformer-specific fragmentation.

Using resonance-enhanced two-photon ionization spectroscopy with mass resolution of jet-cooled molecules, a low-resolution S(1) ← S(0) vibronic spectrum of pseudoephedrine was recorded at the mass channels of three distinct fragments with m/z = 58, 71, and 85. Two of the fragments, with m/z = 71 and 85, are observed for the first time for this molecule. The vibronic spectra recorded at different mass channels feature different patterns, implying that they originate from different conformers in the cold molecular beam, following conformer-specific fragmentation pathways. Highly resolved spectra of all prominent vibronic features were measured, and from their analysis based on genetic algorithms, the molecular parameters of the conformers giving rise to the respective bands have been determined. Comparing the experimental results with those obtained from high-level ab initio quantum chemistry calculations, the observed prominent vibronic bands have been assigned to originate from four distinct conformers. The conformers are separated into two groups that have different fragmentation pathways determined by the different intramolecular interactions.

Water binding sites in 2-para- and 2-ortho-fluorophenylethanol: a high-resolution UV experiment and ab initio calculations.

The singly hydrated complexes of the flexible prototype molecules 2-para-fluorophenylethanol and 2-ortho-fluorophenylethanol have been investigated by combination of high-resolution resonance-enhanced two-photon ionization spectroscopy in a cold supersonic beam and quantum chemistry ab initio calculations. We have identified the conformational structures of the above complexes, which correspond to water binding to the most stable gauche monomer's conformers in both cases. No structural changes of the host molecules upon the attachment of a single water molecule have been found. For the 2-ortho-fluorophenylethanol-water complex we have observed an additional structure with one of the higher-in-energy gauche conformers of the monomer. This corroborates the assumption that the complexation with water stabilizes the higher-energy conformer of the monomer, precluding it from relaxation to the lowest-energy geometry.

Mass-analyzed threshold ionization spectroscopy of ortho fluorinated 2-phenylethanol: identification of an additional gauche conformer.

The cationic ground state of the ortho fluorinated 2-phenylethanol has been investigated by combination of mass-analyzed threshold ionization (MATI) spectroscopy and quantum chemistry ab initio density functional theory (DFT) calculations employing the hybrid functional M05 with cc-pVDZ basis set. The MATI spectra measured via vibronic bands in the S1 intermediate state of the most stable gauche conformer stabilized by an intramolecular OH···π hydrogen bond are structureless. The MATI spectrum recorded via a small band blueshifted by 3 cm−1 from the 0(0)(0) electronic origin of the gauche conformer features well-resolved peaks and is assigned to a cationic gauche structure without an OH···π bond. The ab initio calculations are qualitatively consistent with the experimental observations and show that the presumable conformer giving rise to the observed MATI spectrum retains its structure during ionization, whereas the lowest-energy gauche conformer undergoes a significant structural change resulting in a break of the OH···π bond, thus leading to unfavorable Franck−Condon factors for the threshold ionization.

Mass-analyzed threshold ionization spectroscopy of 2-phenylethanol: probing of conformational changes caused by ionization.

The vibrational structure of the ionic ground state of different conformers of the biologically relevant molecule 2-phenylethanol has been investigated by combination of two-photon two-color mass-analyzed threshold ionization spectroscopy (MATI) and quantum chemical calculations at M05, MP2, and coupled cluster (CC) levels of theory with extended basis sets. MATI spectra recorded via gauche vibronic bands are with poor structure and increasing background, whereas the ones measured via vibronic bands of the anti conformers feature well-resolved vibronic structure in the cation. Ab initio computations predict three stable conformers for the 2-phenylethanol cation out of five initial neutral structures. None of the theoretical structures in the cation features a nonclassical OH...pi hydrogen bond in conjunction with the analysis of the MATI spectra. This provides clear evidence that the OH...pi hydrogen bond stabilizing the lowest-energy gauche conformer in the neutral breaks upon ionization.

Mass analysed threshold ionisation spectroscopy of flexible 2-para-fluorophenylethanol conformers with and without an intramolecular OH...pi bond.

The cationic state of the prototype flexible molecule 2-para-fluorophenylethanol has been investigated by combination of mass-analysed threshold-ionisation (MATI) spectroscopy and quantum chemistry ab initio density functional theory (DFT) calculations employing two different functionals: the B3LYP functional and the new hybrid functional M05. The MATI spectra measured via vibronic bands in the S1 intermediate state belonging to the most stable gauche conformer stabilised by an intramolecular OH...pi hydrogen bond are structureless, while the spectra recorded via bands of the anti conformer feature well-resolved peaks. This result is in a good accord with our theoretical predictions showing that upon ionisation, the anti conformer retains its structure, while the lowest-energy gauche conformer undergoes a significant structural change resulting in a break of the OH...pi bond. This and the good agreement between the measured band positions and the theoretically predicted frequencies for the cationic anti conformer confirm the conformational assignment. The result for the cation provides clear evidence for the existence of a nonclassical intramolecular OH...pi hydrogen bond if the electron density in the aromatic ring is sufficiently high as is the case only for the neutral molecule.

Competition between pi and sigma hydrogen bonds and conformational probing of 2-orthofluorophenylethanol by low-and high-resolution electronic spectroscopy.

The flexible model molecule 2-orthofluorophenylethanol has been investigated by laser-induced fluorescence, and low- and high-resolution resonance-enhanced two-photon ionization spectroscopy in combination with high-level ab initio quantum chemistry calculations. One dominant conformation has been identified in the cold molecular beam corresponding to the most stable theoretically predicted gauche structure stabilized by an intramolecular OH...pi hydrogen bond. A tentative assignment of a higher-lying gauche conformer present in the molecular beam separated by high potential barriers from the most stable one has been made. The missing other higher-energy theoretically predicted conformations most likely relax to the most stable ones during the process of the adiabatic expansion. The good agreement between the experimental and theoretical results demonstrates that even in the case of a substitution with an electronegative atom at the ortho position, bringing about a significant redistribution of the electron density in the benzene ring and providing a convenient binding site for the formation of a competing OH...F sigma hydrogen bond, the nonclassical OH...pi bond remains the preferred binding motif for the most stable conformer.

Specific and nonspecific interactions in a molecule with flexible side chain: 2-phenylethanol and its 1:1 complex with argon studied by high-resolution UV spectroscopy.

Using high-resolution resonance-enhanced two-photon ionization spectroscopy in combination with genetic-algorithm-based computer-aided rotational fit analysis and ab initio quantum chemistry calculations we determined the conformational structure and transition moment orientation in 2-phenylethanol and its 1:1 clusters with argon. The results clearly demonstrate that the gauche structure of 2-phenylethanol, which is stabilized by the intramolecular pi-hydrogen bond between the folded side chain and the benzene ring, is the most abundant in the cold molecular beam. In this conformer the transition moment is rotated by 18 degrees from the short axis of the aromatic ring. Two distinct 1:1 complexes of 2-phenylethanol with argon in a cis- and trans-configuration with respect to the side chain have been found. Employing the Kraitchman [Am. J. Phys. 21, 17 (1953)] analysis we have found that the structure of the 2-phenylethanol moiety and the orientation of the transition moment do not change after the complexation with argon within the experimental accuracy. From the measured band intensities we conclude that in addition to the dispersion interaction of the argon atom with the aromatic ring a hydrogen-bond-type interaction with the terminal -OH group of the side chain stabilizes the cis-structure of the 1:1 complex of 2-phenylethanol with argon.

High-resolution ultraviolet spectroscopy of p-fluorostyrene-water: evidence for a sigma-type hydrogen-bonded dimer.

Ab initio calculations predict four stable conformational structures of the singly hydrated cluster of p-fluorostyrene: two out of plane with pi- and two in plane with sigma-type intermolecular hydrogen bonding between p-fluorostyrene and water. We employed mass-selective resonance-enhanced two-photon ionization high-resolution (70-MHz FWHM laser bandwidth) spectroscopy to partially resolve the rotational structure of the 0(0) (0) origin band of the S(1) <--S(0) electronic transition. A computer-aided fit based on genetic algorithms was used to analyze the experimental high-resolution spectrum and to determine the observed conformational structure. The good agreement between the experimental and the simulated spectra of the 0(0) (0) band and the assignment of the other prominent bands as inter- and intramolecular vibrational progressions clearly demonstrates that the anti in-plane conformer is the most abundant one in the molecular beam. The existence of the sigma-type hydrogen bond between p-fluorostyrene and water manifests that the electron attracting effect of fluorine dominates over the releasing mesomeric effect of the vinyl group and thus a pi-type hydrogen bonding with the aromatic ring is not favored in this case.

Fragmentation and conformation study of ephedrine by low- and high-resolution mass selective UV spectroscopy.

The neurotransmitter molecule, ephedrine, has been studied by mass-selective low- and high-resolution UV resonance enhanced two-photon ionization spectroscopy. Under all experimental conditions we observed an efficient fragmentation upon ionization. The detected vibronic peaks in the spectrum are classified according to the efficiency of the fragmentation, which leads to the conclusion that there exist three different species in the molecular beam: ephedrine-water cluster and two distinct conformers. The two-color two-photon ionization experiment with a decreased energy of the second photon leads to an upper limit of 8.3 eV for the ionization energy of ephedrine. The high-resolution (70 MHz) spectrum of the strongest vibronic peak in the spectrum measured at the fragment (m/z=58) mass channel displays a pronounced and rich rotational structure. Its analysis by the use of a specially designed computer-aided rotational fit process yields accurate rotational constants for the S(0) and S(1) states and the transition moment ratio, providing information on the respective conformational structure.

Methods for permanent conservation of biological objects and anatomic preparations in synthetic resins.

Two methods for preparing packets of synthetic resin for permanent preservation of biological objects and anatomical tissue have been developed. The first method is applied when adding corrosive preparations to epoxide resin. The corrosive preparation is soaked in a mixture of epoxide resin and hardener in a ratio, experimentally determined. The induration proceed at room temperature for 12 h. The second method has two options and is applied for the conservation of biological objects and anatomical preparations in polymethylmethacrylate by a successive immersing of the object in a system of dehydrating mixtures: 50%, 70%, 90% and 96% water solution of methanol and ethanol and in a mixture of acetone and ethanol (1:1) and in acetone or in methylene chloride. The object, thus prepared, is impregnated in vacuum with polymer of methylmethacrylate, benzoyl peroxide and stearic acid or in a composition containing: methylmethacrylate, benzoyl peroxide, dibutylphthalate and tertiary aromatic amine, in optimum correlations of the components, experimentally determined. The induration proceed by heating in a water bath (37 + 3 degrees C) for 3 h and at 30 degrees C temperature in the course of 6-8 h in the first option or at room temperature for about 3 days in the second option. The advantages of the proposed methods are: the use of cheap and available materials for the production of a simplified technological scheme of strongly transparent packages, preserved over a long period; preserving the sizes, the form and natural colour of the objects and preparations as well as a possibility for selective tinting of the separate tissues and systems in the preserved biological objects and anatomical preparations; a possibility for stereomicroscopic observation of the objects and preparations preserved.

[Renal carcinoma with bilateral location and in the single kidney]. / Bubrechen kartsinom s dvustranna lokalizatsiia i v edinstven bubrek.

Patients with renal carcinoma, admitted to the university urological clinic in Rostock, Germany, over a ten-year period (1980 through 1990), are analyzed retrospectively. In ninety-seven patients the histological diagnosis is confirmed during operation. Renal carcinoma with bilateral location is diagnosed in eight of them. Four patients present a single kidney because of previous neoplastic nephrectomy of the other one. Apart from that there are five patients with carcinoma of the only kidney due to other causes: aplasia of the first kidney (4 cases) and nephrectomy of a pyelonephrotic kidney (1 case). The total number of carcinomas involving the only kidney amount to nine, and in seven of them the organ salvaging operation performed is successful. In two patients, owing to involvement of the wall discovered during operation, this intervention proves impracticable. Here the operation terminates with radical nephrectomy, with the patients undergoing hemodialysis, and preparation for renal transplantation. The survival term exceeds five years in one patient alone. Two deaths occur during the operation, attributed to the advanced stage of the tumor: in 4 patients T4, and in the remainder (4)-T3a and T3b.

[The leading symptoms in patients with renal carcinoma]. / Vodeshti simptomi pri bolni s bubrechen kartsinom.

UNLABELLED: The incidence of the leading symptoms of renal cancer in 97 patients operated at the University Urologic Clinic in Rostock, Germany, was studied. In all patients the diagnosis was clinched by histologic examination. RESULTS: gross hematuria had 43 per cent of the patients; pain in the lumbar area--29 per cent; arterial hypertension--27 per cent; change finding--21 per cent; conventional tumor symptoms--17 per cent; palpable tumor--11 per cent; classical triad--8 per cent. The incidence of the conventional tumor symptoms was: loss of weight--17 per cent; fever--21 per cent; malaise--17 per cent. The results of this study showed that gross hematuria was the most common symptom. These results as a whole considerably differ from data reported by other authors. Common to all is however the top incidence of gross hematuria and pain in the lumbar area.

[The incidence, localization, sex and mean age in patients with renal carcinoma]. / Chestota, lokalizatsiia, pol i sredna vuzrast pri bolni s bubrechen kartsinom.

Retrospective analysis was made of the clinical case records of 97 nephrectomized patients with renal cancer at the University Urologic Clinic in Rostock, Germany. The Student-Fisher t-criterion was used for statistical processing of the results. The stage of the disease was determined in accordance with the histologic classification of pTNM, suggested in 1988 by the European Organization for Cancer Research and Treatment. Patients with malignant diseases of the urogenital tract accounted for 6.1 per cent of all patients treated at the Urologic Clinic. Malignant disease of the kidney alone comprised 1.7 per cent and of renal cancer--1.5 per cent. In 49 per cent of the patients renal cancer was localized in the left kidney, in 42 per cent--the right kidney, and 9 per cent both kidneys were involved. The male: female ratio was 2.2:1. Mean patient age was 57 years (males 58.1, females 55.9 years).

[Survival and prognosis in renal carcinoma]. / Prezhiviaemost i prognoza pri bubrechniia kartsinom.

A study of the survival and prognosis of renal cancer was performed in 97 patients in different stage of the disease. Mean survival was 2.9 years for males and 3.1 years for females (no statistical significance as to sex). It was shown that with advancing stage of the disease decreased patient survival (T-2 = 4.1 yrs., T-3A = 2.5 yrs., T-3B = 1.3 yrs). The same tendency was observed to a higher degree in N-stage, according to the TNM classification: no single patient survived in N-2 stage beyond 3 years. Observations in M-2 stage showed a much shorter survival time: there was no survival beyond 1 year in M-2 stage.

[The surgical treatment of patients with renal carcinoma]. / Operativno lechenie na bolni s bubrechen kartsinom.

A retrospective study of 118 patients with renal cancer, treated at the University Urologic Clinic in Rostock, Germany, for the period Jan. 1980-March 1990 was performed. Twenty-one patients (17.8 per cent) were in advanced stage of the disease which made operative treatment impossible. Radical nephrectomy was performed in 83 patients: transperitoneal with pararectal approach in 79 and lumbotomy in 4. Partial renal resection was performed in 7 patients, in 5 of them with local hypothermia. The operation in 7 patients terminated with probatory laparotomy because of infiltrative growth of the tumor in adjacent tissues, v. cava included. Probatory laparotomy served for intraoperative biopsy, allowing to establish histologic diagnosis. Six patients died within a month after the operation (6.15 per cent postoperative lethality). Intraoperative complications developed in 4 patients: rupture of the spleen in 2 requiring splenectomy, lesion of colon descendens which necessitated transversectomy--in 1 patient, and rupture of the aorta in 1 patient successfully controlled with two-layer suture of the aortic wall.

[Antibacterial activity of chlorquinaldol esters and 2-styryl-substituted derivatives]. / Izsledvane na antibakteriinata aktivnost na niakoi esteri i zamesteni 2-stirilni proizvodni na khlorkhinaldola.

Studied was the bacteriostatic activity of a total of 17 new esters and replaced 2-styryl derivatives of chlorquinaldol. Determined were also the lowest concentrations that suppressed the growth of organisms. Some of the compounds showed higher activity and broader spectrum of antibacterial qualities, mainly against Escherichia coli, Salmonella gallinarum, and Salmonella cholerae suis as compared to the initial therapeutic preparation chlorquinaldol. It was found that the presence of chlorine atoms either in the second or in the second and fourth place in the benzene nucleus of the esters studied, the presence of a NO2-group in the third place of the same nucleus, and the presence of an extranuclear hydroxyacetyl remainder in the ester grouping could lead to a rise of the antibacterial activity. The presence of an F atom in the second and third place of the benzene nucleus of the sterile grouping also raised the activity of these compounds.