CS Molecule Research Articles

A Spectral Line Survey from 138.3 to 150.7 GHz toward Orion‐KL

We present the results of a spectral line survey from 138.3 to 150.7 GHz toward Orion-KL. The observations were made using the 14 m radio telescope of Taeduk Radio Astronomy Observatory. Typical system temperatures were between 500 and 700 K, with the sensitivity between $0.02 - 0.06$ K in units of $\rm T_A^*$. A total of 149 line spectra are detected in this survey. Fifty lines have been previously reported, however we find 99 new detections. Among these new lines, 32 are `unidentified', while 67 are from molecular transitions with known identifications. There is no detection of H or He recombination lines. The identified spectra are from a total of 16 molecular species and their isotopic variants. In the range from 138.3 to 150.7 GHz, the strongest spectral line is the J=3-2 transition of CS molecule, followed by transitions of the $\rm H_2CO$, $\rm CH_3OH$, $\rm CH_3CN$, and $\rm SO_2$. Spectral lines from the large organic molecules such as $\rm CH_3OH$, $\rm CH_3OCH_3$, $\rm HCOOCH_3$, $\rm C_2H_5CN$ and $\rm CH_3CN$ are prominent; with 80 % of the identified lines arising from transitions of these molecules. The rotational temperatures and column densities are derived using the standard rotation diagram analysis for $\rm CH_3OH$ ($\rm ^{13}CH_3OH$), $\rm HCOOCH_3$, $\rm CH_3CN$ and $\rm SO_2$ with $\rm 10\sim 270 K$ and $\rm 0.2\sim 20\times 10^{15} cm^{-2}$. These estimates are fairly comparable to the values for the same molecule in other frequency regions by other studies.

Spectroscopic Observations in the 3-mm Wavelength Range at CrAO RT-22 Radiotelescope Using an Acousto-Optical Spectrum Analyzer

Within the framework of a multi-year program of dense interstellar gas studies, we performed a new series of observations at the CrAO RT-22 radiotelescope in July 1998 using an improved 3-mm wavelength receiving facility. An acousto-optical spectrum analyzer (AOS) was used for the first time for the spectral analysis of incoming radiation. The AOS has larger bandwidth compared to the filter spectrum analyzer used previously and simplifies tuning SIS-mixer circuits and frequency converters. Using this facility, we observed a number of star-forming regions including clouds associated with bright IR sources and ultracompact HII regions as well as clouds with high-velocity outflows in the HCO+, 13CO, HCN, and CS molecule lines.

Crystal structure–solubility relationships in optical resolution by diastereomeric salt formation of DL-phenylglycine with (1S )-(+)-camphor-10-sulfonic acid

The experimentally-optimized optical resolution of DL-phenylglycine (PG) with (1S)-(+)-camphor-10-sulfonic acid ((+)-CS) afforded the crystalline D-PG·(+)-CS salt in 45.7% isolated yield and 98.8% optical purity. This excellent resolution has been studied by comparison of the crystal properties of the diastereomeric salt pair, D- and L-PG·(+)-CS. Thermoanalysis (DSC) of the less-soluble D-PG·(+)-CS showed a higher melting point and a larger enthalpy of fusion than those of the more-soluble L-PG·(+)-CS. The difference in the solubilities of the two salts in water is very large because the more-soluble L-PG·(+)-CS is freely soluble. The X-ray crystal structure of D-PG·(+)-CS shows a dense and stable molecular conformation of alternating PG cation layers and (+)-CS anion layers, whereas that of L-PG·(+)-CS shows a coarser molecular conformation consisting of characteristic “holey” vacancy layers, an important factor in its free solubility. The difference in the two characteristic structures could be closely related to the high efficiency of the resolution. A geometrical discussion of the (+)-CS molecule predicted that its excellent resolving ability may be due to its combining two structural functions; a hydrophilic flexible methanesulfonic acid site and a hydrophobic rigid camphor site.

Quartet and sextet states of CS−

The potential energy and spin–orbit functions have been calculated for several electronic states of CS and CS−. Comparison with experimental data for CS shows very good agreement, making reliable predictions possible for the CS− molecule such as the existence of long-lived metastable states. The a 4Σ−, b 4Π, and a 6Π states were found to lie energetically below the triplet or quintet states of the CS molecule. The calculated spin–orbit integrals between the electronic states suggest that the depletion of the J=5/2 or 7/2 components in the Π states will mainly occur via weak interactions with the electron continuum wave.

Transition moment function, transition probabilities, and radiative lifetimes in the A [formula omitted]–X [formula omitted] system of the CS molecule

Very accurate potential energy curves for the X 1 Σ + and A 1 Π states of the CS molecule are reported using the CASSCF/MRSDCI approach. A theoretical description of the transition moment function of the X 1 Σ + –A 1 Π system over a large interval of internuclear distances is also presented which discloses relevant features about this function as yet unsuspected experimentally. Emission probabilities data also provide a trustful description of the relative intensities, and the radiative lifetimes are certainly a good reference for comparison with experimentally unperturbed results. For the A 1 Π ( v′=0, J′=1) state this work estimates an unperturbed radiative lifetime of 167 ns.

A study of the CS molecule with photoelectron spectroscopy using synchrotron radiation

The CS molecule has been studied with constant ionic state (CIS) spectroscopy in the photon energy range 11.2–19.5 eV using radiation from a synchrotron source. The spectra were obtained by monitoring the intensities of the first three vibrational components in the first photoelectron band as a function of photon energy. The structured spectra obtained have been analyzed in terms of excitation to and autoionization from Rydberg states with A 2Π, B 2Σ+, and C 2Σ+ ionic cores. Photoelectron spectra of the first band of CS recorded at selected resonant energies showed extended vibrational structure which was used to obtain improved ionic state vibrational constants for CS+ X 2Σ+ compared to those derived from an off-resonance spectrum.

Three‐dimensional Non‐LTE Radiative Transfer of CS in Clumpy Dense Cores

With a Monte Carlo radiative transfer code we have investigated excitation conditions of the CS molecule in dense cores and synthesized line profiles for several transitions of both CS and C34S. We took two kinds of models of the dense core: a clumpy and a smooth model. In the clumpy model, the core is composed of many small clumps, whose volume filling factor f is unity in the central region of r ≤ 0.2R and then declines as f r-1.5. However, H2 number density in the clump is kept constant and also independent of the clump position. The mean number density, nH2(r), is thus constant in the central part and then decreases as the same power law. In the smooth model, the gas fills the core completely, and its local density exactly follows the mean density of the clumpy model. For both models, each clump has thermal as well as bulk motions, velocity dispersion of the latter being proportional to r0.5. In the clumpy structured core, the excitation temperature of the CS transitions is found to be generally constant over an entire region. As a consequence, the synthesized profile is of a Gaussian shape superposed with some wiggles, which reflects the existence of clumps under the bulk motion. The trend of flat distribution of excitation temperature becomes more prominent for optically thin transitions of the rarer species C34S. The profiles develop flat-top features with minor wiggles only when the core becomes extremely thick in the optical sense. On the other hand, wider profiles that have self-absorption are synthesized in the smooth core. The self-absorption is formed by a steep gradient in the radial distribution of the excitation temperature. For optically thin C34S transitions, both the clumpy and the smooth cores exhibit profiles close to a Gaussian shape. Comparing line parameters derived in the Monte Carlo code and those by the large-scale velocity gradient calculations, we found that only the clumpy models can give correct estimations of the density and abundance of the cores. Moreover, we have shown that clump parameters, such as clump size and number of clumps in a beam, are reasonably estimated by Tauber's simple method. Since the opaque line reflects properties of a region of τ ~ 1, local unbalance of bulk velocity distribution in the core, for instance, often results in a blue peak stronger than the red peak in the CS line profiles. Thus it should be noted that a combination of this feature of the optically thick line and the single peak of the thin one may not necessarily imply a signature of infall.

Cholesteryl hemisuccinate treatment protects rodents from the toxic effects of acetaminophen, adriamycin, carbon tetrachloride, chloroform and galactosamine

In addition to its use as a stabilizer/rigidifier of membranes, cholesteryl hemisuccinate, tris salt (CS) administration has also been shown to protect rats from the hepatotoxic effects of carbon tetrachloride (CCl 4). To further our understanding of the mechanism of CS cytoprotection, we examined in rats and mice the protective abilities of CS and the non-hydrolyzable ether form of CS, γ-cholesteryloxybutyric acid, tris salt (CSE) against acetaminophen-, adriamycin-, carbon tetrachloride-, chloroform-, and galactosamine-induced toxicity. The results of these studies demonstrated that CS-mediated protection is not selective for a particular species, organ system or toxic chemical. A 24-h pretreatment of both rats and mice with a single dose of CS (100mg/kg, i.p.), resulted in significant protection against the hepatotoxic effects of CCl 4, CHCl 3, acetaminophen and galactosamine and against the lethal (and presumably cardiotoxic) effect of adriamycin administration. Maximal CS-mediated protection was observed in experimental animals pretreated 24 h prior to the toxic insult. These data suggest that CS intervenes in a critical cellular event that is an important common pathway to toxic cell death. The mechanism of CS protection does not appear to be dependent on the inhibition of chemical bioactivation to a toxic reactive intermediate (in light of the protection observed against galactosamine hepatotoxicity). However, based on the data presented, we can not exclude the possibility that CS administration inhibits chemical bioactivation. Our findings do suggest that CS-mediated protection is dependent on the action of the intact anionic CS molecule (non-hydrolyzable CSE was as protective as CS), whose mechanism has yet to be defined.

Cometas: I - Populações e Intensidades de Nove Bandas Vibracionais do Monossulfeto de Carbono (12C32S).

A theoretical study of resonance fluorescence mechanism for carbon monosulfide (12C32S) in the comae of Comets West (1976VI) and P/Bradfield (1979X) using the solar radiation field is presented. We obtained the relative populations in several different vibrational levels, and the intensities of 9 vibrational bands of CS molecule.

Use of fluorescence spectroscopy of CS for measurements of electric fields in a discharge plasma

It is demonstrated that the use of LIF spectroscopy of CS molecules provides sensitive measurements of plasma electric fields with high spatial resolution. The experiment was performed in a helium glow discharge which was produced in a discharge vessel applying a voltage to two gold-plated electrodes (60 mm in diameter, 40 mm spacing). The CS molecule admixture was generated by a rf discharge in a gas flow system outside the discharge vessel. The plasma parameters in the negative glow discharge were obtained by probe measurements. The electron density was about and the electron temperature was 0.2 eV on the discharge axis for , and helium gas pressure . The measured electric field strength was in the range of and its spatial distribution in the cathode fall region is in good agreement with cathode fall theory.

Mass spectrometric study of the photoionization of CS. The dissociation energy of the CS molecule

A mass spectrometric study of the photoionization of CS provides 11.319 ± 0.006 eV for the ionization potential, in agreement with literature values. Three Rydberg series converging to the C2Σ+ state of the molecular ion are identified. Their limit is 18.003 ± 0.006 eV. The threshold for dissociative ionization of CS towards S+ is located at 70.05 ± 0.1 nm and yields D0(CS, 0 K) = 709.4 ± 2.5 kJ/mol. This result is briefly compared with prior data. D0(CS, 0 K) = 709.6 ± 1.2 kJ/mol and DCS+ 0 K) = 617.1 ± 1.3 kJ/mol are selected as the best estimates for these quantities.

A comparison of finite basis set and finite difference methods for the ground state of the CS molecule

A comparison is made of the accuracy with which the total electronic energy can be calculated by using either the finite basis set approach (the algebraic approximation) or finite difference methods in calculations using the Hartree-Fock model for the ground (X1 Sigma +) state of the carbon monosulphide molecule. The CS molecule is considered as a prototype for systems containing atoms from different rows of the periodic table. The convergence of the calculations carried out within the algebraic approximation is monitored by employing systematically constructed basis sets of increasing size. The dependence of the finite difference calculations on the numerical grid employed is studied.

High density tracers in outflow regions: NH3 vs. CS

We present CS(J = 1 → 0) observations of the high density gas in a sample of eleven star forming regions with molecular or optical outflows. The sources of this sample cover a wide range of physical sizes. All these sources had been previously mapped in NH3 (1, 1) with similar angular resolution. In all the sources of this sample CS emission was detected, indicating a global correlation between the emissions traced by the CS and the NH3 molecules. However, the detailed characteristics of these two emissions (e.g., the extent and the location of the emission peak) show, in general, significant differences in the sources which are well resolved by the beam. As a general trend, the emission traced by the NH3 molecule appears as compact clumps which engulf an outflow activity center. In contrast, the emission traced by the CS molecule, usually more extended, appears as a background which connects different outflow activity centers associated with each NH3 clump.

In search of evidence for protostellar collapse - A systematic study of line formation in low-mass dense cores

view Abstract Citations (129) References (39) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS In Search of Evidence for Protostellar Collapse: A Systematic Study of Line Formation in Low-Mass Dense Cores Zhou, Shudong Abstract Radiative transfer models of low-mass dense cores are presented as depicted in two theoretical models of protostellar collapse: the Larson-Penston flow and the theory of Shu and coworkers based on the 'inside-out collapse' model. In particular, line profiles of the first three rotational transitions of the CS molecule are calculated for hypothetical dense cores evolving according to these theories. The results are compared with CS observations of nearby dense cores. It is shown that the Larson-Penston flow overestimates the velocity width of the CS lines by a large margin and cannot be reconciled with the observations. In contrast, the theory of Shu and coworkers predicts the right velocity width for the CS lines during the formation stage of dense cores. The models indicate that 'inside-out' collapse should significantly enhance the CS line widths and the enhancement should be easily observable, particularly at high resolution. A list of line properties are presented for hypothetical dense cores undergoing 'inside-out' collapse. These properties are found to be unique to collapse motions; hence, they can be used as a guide in searching for protostellar collapse. Publication: The Astrophysical Journal Pub Date: July 1992 DOI: 10.1086/171572 Bibcode: 1992ApJ...394..204Z Keywords: Gravitational Collapse; Line Spectra; Protostars; Radiative Transfer; Star Formation; Astronomical Spectroscopy; Computational Astrophysics; Interstellar Matter; Molecular Clouds; Stellar Cores; Stellar Models; Astrophysics; ISM: CLOUDS; RADIATIVE TRANSFER; STARS: FORMATION full text sources ADS | data products SIMBAD (1)

Anti-cyclosporine monoclonal antibodies and their anti-idiotopic counterpart: Structure and biological activity

In order to study the structural and functional mimicry of an antigen by anti-idiotyplc antibodies, we generated anti-idiotoplc monoclonal antibodies (anti-Id mAbs) against a mAb (R45-45-11) with specificity for the immunosuppressive cyclic undecapeptide cyclosporine (Cs; Sandimmune R). Three out of five anti-Id mAbs inhibited the binding of Cs to the anti-Cs mAb R45-45-11. All anti-Id mAbs cross-reacted only with one (anti-Cs mAb V45-271-10) out of 19 anti-Cs mAbs. The anti-Cs mAb V45-271-10 recognizes an epitope on the Cs molecule which is very similar to that recognized by R45-45-11. R45-45-11 and V45-271-10 differ only by one amino acid in the variable region. The anti-Id mAbs which recognize combining site-associated idiotopes (Ids) reverse the blocking effect of the anti-Cs mAb R45-45-11 on Cs immunosuppression in vitro. The sequences of the variable regions of heavy and light chain of one anti-Id mAb were determined. X-ray analysis of the corresponding Fab fragment, either alone or complexed with the Fab fragment of the Id, is currently in progress.

Novel monoclonal antibodies to cyclosporine A: Characterization and epitope mapping with cyclosporine analogs and cyclophilin

Monoclonal antibodies to cyclosporine A (Cs), a potent immunosuppressant, were generated in BALB/c mice using a novel antigen prepared by linking Cs to a protein carrier via a photoactive cross-linking reagent, 4-benzoylbenzoic acid (BBa). Twenty-two monoclonal anti-Cs antibodies were generated, using Cs-BBa-bovine serum albumin (Cs-BBa-BSA) as the immunogen. They were characterized with respect to affinity by Scatchard analysis of a radioimmunoassay (RIA), and with respect to specificity by an ELISA in which a series of singly substituted Cs derivatives were examined as inhibitors. McAb affinities ranged from 5 × 10 −8 M to 2 × 10 −10 M, Based on ELISA inhibition data with Cs analogs, and on the binding to two Cs-BSA conjugates in which opposite sides of the Cs molecule are exposed, the antibodies fell into five epitope recognition groups. Binding to Cs was also studied by ELISA in competition with cyclophilin (CyP), a Cs-binding protein whose epitope specificity has been well characterized. Competition by CyP was found to correlate with antibody specificity, not with affinity, i.e. CyP competed best with antibodies having specificities most similar to that of CyP. Epitope mapping can, therefore, be accomplished in a system in which two different species of binding proteins compete for the same antigen. This type of characterization may be useful in identifying antibodies whose combining sites mimic those of a receptor.

CS multitransitional studies of density distribution in star-forming regions. I - The NGC 2071 region

The NGC 2071 molecular cloud was observed in the J = 2 to 1, 5 to 4, 6 to 5, and 7 to 6 transitions of the CS molecule with resolutions of 11 - 24 arcsec. The emission in all transitions peaks strongly at the IRS 1 position. The data are best described by a spherically symmetric gas distribution centered on IRS 1, surrounding a central cavity 0.01 pc in radius. In addition, high-velocity (about 10 km/s) wing emission is seen in both the J = 2 to 1 and 7 to 6 lines, which had better signal-to-noise ratios than the other two lines. The bipolar morphology is clearly seen in the CS J = 2 to 1 high-velocity emission, but the CS 7 to 6 high-velocity emission is unresolved. Both appear to come from dense gas in the molecular outflow. The morphology of the CS emission is in good agreement with dust continuum emission but is strikingly different from the pattern of NH3 emission. Chemical differentiation of the two molecules must be present in the source. The agreement between CS and dust emission suggests that CS is a better tracer of gas near young stellar objects than NH3. 41more » refs.« less

Physical parameters in extragalactic star forming regions

To use a molecule as a diagnostic of a single star forming region, one has to observe it in different transitions. That is especially true for galaxies, where the beam filling factor is small and unknown. From studies of Galactic objects, the CS molecule is a good tracer of dense gas. Toward the IR galaxies NGC 253, IC 342 and M 82, Mauersberger and Henkel (1989) observed the J=2—1, 3—2 and 5—4 transitions of CS at 3, 2 and 1.3 mm wavelength, repectively. They also measured emission of the isotope C34S, which has an abundance ∼ 1/23 that of the main isotope. This study revealed that the H2 densities in the circumnuclear gas exceed 104, and, in the case of NGC 253, 105 cm−3. In all three cases, the distribution of the dense gas traced out by CS follows the CO distribution.

Physical parameters in extragalactic star forming regions

To use a molecule as a diagnostic of a single star forming region, one has to observe it in different transitions. That is especially true for galaxies, where the beam filling factor is small and unknown. From studies of Galactic objects, the CS molecule is a good tracer of dense gas. Toward the IR galaxies NGC 253, IC 342 and M 82, Mauersberger and Henkel (1989) observed the J=2—1, 3—2 and 5—4 transitions of CS at 3, 2 and 1.3 mm wavelength, repectively. They also measured emission of the isotope C34S, which has an abundance ∼ 1/23 that of the main isotope. This study revealed that the H2 densities in the circumnuclear gas exceed 104, and, in the case of NGC 253, 105 cm−3. In all three cases, the distribution of the dense gas traced out by CS follows the CO distribution.

Analysis of the structural diversity of monoclonal antibodies to cyclosporine

The immunosuppressive cyclic undecapeptide cyclosporine (Cs) represents a useful model for studying the molecular basis of antibody-antigen interactions. The three-dimensional structure of the Cs molecule is known and a large panel of monoclonal antibodies (mAbs) to Cs has been well characterized by cross-reactivity studies with numerous Cs analogs. In the present study, the sequences of the variable regions of seven mAbs to Cs were determined and a striking relationship was found between the expressed variable region genes and the Cs recognition pattern. An analysis of the length and hydrophobic content of the hypervariable regions and sequence similarities suggested that the heavy chain plays a major role in Cs recognition. Different fine specificities were observed for mAbs exhibiting identical light chains, while two antibodies differed by only a single amino acid located in the heavy chain. The presence of a duplication of 12 nucleotides within the heavy chain third hypervariable region of two antibodies suggests the existence of an additional mechanism for creating antibody diversity.