Journal articles: 'Cold Molecule'

1

Campbell, Wesley C., Cheong Chan, David DeMille, John M. Doyle, Gerald Gabrielse, Yulia V. Gurevich, Paul W. Hess, et al. "Advanced cold molecule electron EDM." EPJ Web of Conferences 57 (2013): 02004. http://dx.doi.org/10.1051/epjconf/20135702004.

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Wang, Dajun. "A versatile cold-molecule collider." Nature 572, no. 7768 (August 2019): 180–81. http://dx.doi.org/10.1038/d41586-019-02356-3.

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Gandhi, Suketu R., Qi Xun Xu, Thomas J. Curtiss, and Richard B. Bernstein. "Oriented molecule beams: focused beams of rotationally cold polar polyatomic molecules." Journal of Physical Chemistry 91, no. 21 (October 1987): 5437–41. http://dx.doi.org/10.1021/j100305a011.

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Ishkhanyan, A., R. Sokhoyan, B. Joulakian, and K. A. Suominen. "Rosen–Zener model in cold molecule formation." Optics Communications 282, no. 2 (January 2009): 218–26. http://dx.doi.org/10.1016/j.optcom.2008.10.008.

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Pawlak, Mariusz, Yuval Shagam, Edvardas Narevicius, and Nimrod Moiseyev. "Adiabatic theory for anisotropic cold molecule collisions." Journal of Chemical Physics 143, no. 7 (August 21, 2015): 074114. http://dx.doi.org/10.1063/1.4928690.

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Suzuki, H., M. Ohishi, M. Morimoto, N. Kaifu, P. Friberg, W. M. Irvine, H. E. Matthews, and S. Saito. "Recent Observations of Organic Molecules in Nearby Cold, Dark Interstellar Clouds." Symposium - International Astronomical Union 112 (1985): 139–44. http://dx.doi.org/10.1017/s0074180900146443.

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We report recent investigations of the organic chemistry of relatively nearby cold, dark interstellar clouds. Specifically, we confirm the presence of interstellar tricarbon monoxide (C3O) in Taurus Molecular Cloud1 (TMC-1); report the first detection in such regions of acetaldehyde (CH3CHO), the most complex oxygen-containing organic molecule yet found in dark clouds; report the first astronomical detection of several molecular rotational transitions, including the J=18−17 and 14−13 transitions of cyanodiacetylene (HC5N), the 101−000 transition of acetaldehyde, and the J=5−4 transition of C3O; and set a significant upper limit on the abundance of cyanocarbene (HCCN) as a result of the first reported interstellar search for this molecule.

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Fisch, L., and G. Kurizki. "Free matter wavepacket teleportation via cold-molecule dynamics." Europhysics Letters (EPL) 75, no. 6 (September 2006): 847–53. http://dx.doi.org/10.1209/epl/i2006-10205-7.

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Ishkhanyan, A. M., B. Joulakian, and K. A. Suominen. "Two strong nonlinearity regimes in cold molecule formation." European Physical Journal D 48, no. 3 (June 13, 2008): 397–404. http://dx.doi.org/10.1140/epjd/e2008-00117-0.

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CHIN, CHENG, ANDREW J. KERMAN, VLADAN VULETIĆ, and STEVEN CHU. "CONTROLLED ATOM-MOLECULE INTERACTIONS IN ULTRACOLD GASES." Modern Physics Letters A 18, no. 02n06 (February 28, 2003): 398–401. http://dx.doi.org/10.1142/s0217732303010557.

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We observe and study the dynamic formation of cold Cs 2 molecules near collision Feshbach resonances in a cold cesium sample. The resonance Iinewidth is as low as E/h = 5 kHz , or equivalently, 10-11 eV. We suggest that few-atom, interaction effects can be studied in a 3D optical lattice where several atoms can be confined and isolated in an optical cell, which allows exquisite control of the atomic density and the interaction cross section.

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10

Horchani, R. "Cold molecules: Formation, ro-vibrational cooling and electronic conversion." International Journal of Modern Physics B 30, no. 14 (June 2, 2016): 1630010. http://dx.doi.org/10.1142/s0217979216300103.

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The possibility of controlling all the motion as well as the internal quantum state of a sample of molecules is a long term goal in the cold molecules field. Although many different techniques have been used to produce ultra-cold molecules, in this paper, we will concentrate on the optical pumping technique successfully used to achieve rotational and vibrational cooling of Cs2molecules. We will review the different photo-association schemes for molecule formation, the detection schemes through photoionization, the ro-vibrational cooling into a single level and finally the electronic conversion. In addition, we will present a theoretical model for both ro-vibrational cooling and electronic conversion that can be used for the preparation of different experiments.

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Suganuma, T., K. Okada, N. Kimura, K. Shiina, M. Wada, and H. A. Schuessler. "A Stark velocity filter for studying cold polar molecule–molecular ion reactions." Journal of Physics: Conference Series 388, no. 10 (November 5, 2012): 102002. http://dx.doi.org/10.1088/1742-6596/388/10/102002.

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12

Kurić, Lutvo. "Why Hot Water Freezes Faster than Cold?" International Letters of Chemistry, Physics and Astronomy 32 (April 2014): 119–34. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.32.119.

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The modern science mainly treats the biochemical basis of sequencing in bio-macromolecules and processes in chemistry and biochemistry. In these informational cybernetic principles we seek to answer the following question: Why hot water freezes faster than cold? These principles determine the freezing point of water. Determine that the hot water freezes faster than cold. What we did is the following: We translated the physical and chemical parameters from the language of water into the digital language of programmatic, cybernetic and information principles. This we did by using the adequate mathematical algorithms. By using chemical-information procedures, we calculated the numerical value for the information content of molecule of water. What we got this way is the digital picture of this molecule. These digital pictures reveal to us a whole new dimension of water. They reveal to us that the chemical process of this molecule is strictly conditioned and determined by programmatic, cybernetic and information principles.

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13

Kurić, Lutvo. "Why Hot Water Freezes Faster than Cold?" International Letters of Chemistry, Physics and Astronomy 32 (April 22, 2014): 119–34. http://dx.doi.org/10.56431/p-zr3pn0.

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The modern science mainly treats the biochemical basis of sequencing in bio-macromolecules and processes in chemistry and biochemistry. In these informational cybernetic principles we seek to answer the following question: Why hot water freezes faster than cold These principles determine the freezing point of water. Determine that the hot water freezes faster than cold. What we did is the following: We translated the physical and chemical parameters from the language of water into the digital language of programmatic, cybernetic and information principles. This we did by using the adequate mathematical algorithms. By using chemical-information procedures, we calculated the numerical value for the information content of molecule of water. What we got this way is the digital picture of this molecule. These digital pictures reveal to us a whole new dimension of water. They reveal to us that the chemical process of this molecule is strictly conditioned and determined by programmatic, cybernetic and information principles.

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14

Chang, Yuan-Pin, Karol Długołęcki, Jochen Küpper, Daniel Rösch, Dieter Wild, and Stefan Willitsch. "Specific Chemical Reactivities of Spatially Separated 3-Aminophenol Conformers with Cold Ca+ Ions." Science 342, no. 6154 (October 3, 2013): 98–101. http://dx.doi.org/10.1126/science.1242271.

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Many molecules exhibit multiple rotational isomers (conformers) that interconvert thermally and are difficult to isolate. Consequently, a precise characterization of their role in chemical reactions has proven challenging. We have probed the reactivity of specific conformers by using an experimental technique based on their spatial separation in a molecular beam by electrostatic deflection. The separated conformers react with a target of Coulomb-crystallized ions in a trap. In the reaction of Ca+ with 3-aminophenol, we find a twofold larger rate constant for the cis compared with the trans conformer (differentiated by the O–H bond orientation). This result is explained by conformer-specific differences in the long-range ion-molecule interaction potentials. Our approach demonstrates the possibility of controlling reactivity through selection of conformational states.

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15

YE, JUN, SEBASTIAN BLATT, MARTIN M. BOYD, SETH M. FOREMAN, ERIC R. HUDSON, TETSUYA IDO, BENJAMIN LEV, et al. "PRECISION MEASUREMENT BASED ON ULTRACOLD ATOMS AND COLD MOLECULES." International Journal of Modern Physics D 16, no. 12b (December 2007): 2481–94. http://dx.doi.org/10.1142/s0218271807011826.

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Ultracold atoms and molecules provide ideal stages for precision tests of fundamental physics. With microkelvin neutral strontium atoms confined in an optical lattice, we have achieved a fractional resolution of 4 × 10-15 on the 1S0–3P0 doubly forbidden 87 Sr clock transition at 698 nm. Measurements of the clock line shifts as a function of experimental parameters indicate systematic errors below the 10-15 level. The ultrahigh spectral resolution permits resolving the nuclear spin states of the clock transition at small magnetic fields, leading to measurements of the 3P0 magnetic moment and metastable lifetime. In addition, photoassociation spectroscopy performed on the narrow 1S0–3P1 transition of 88 Sr shows promise for efficient optical tuning of the ground state scattering length and production of ultracold ground state molecules. Lattice-confined Sr 2 molecules are suitable for constraining the time variation of the proton–electron mass ratio. In a separate experiment, cold, stable, ground state polar molecules are produced from Stark decelerators. These cold samples have enabled an order-of-magnitude improvement in the measurement precision of ground state, Λ doublet microwave transitions in the OH molecule. Comparing the laboratory results to those from OH megamasers in interstellar space will allow a sensitivity of 10-6 for measuring the potential time variation of the fundamental fine structure constant Δα/α over 1010 years. These results have also led to improved understandings of the molecular structure. The study of the low magnetic field behavior of OH in its 2Π3/2 ro-vibronic ground state precisely determines a differential Landé g factor between opposite parity components of the Λ doublet.

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16

Menten, Karl M. "Interstellar methanol masers." Symposium - International Astronomical Union 206 (2002): 125–26. http://dx.doi.org/10.1017/s0074180900222213.

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The asymmetric rotor molecule methanol (CH3OH) has hundreds of transitions at centimeter-, millimeter-, and submillimeter wavelengths. Many of these are excited in the hot (T ≳ 150 K), dense (n ≳ 106 cm−3) molecular cloud cores surrounding newly formed massive stars or protostars. The high temperatures in these cores cause evaporation of icy grain mantles, releasing copious amounts of complex molecules, such as methanol, in the gas phase, which in hot cores has abundances (up to 10−6 relative to H2) that are two or more orders of magnitude higher than in cold dark clouds.

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17

Zhang, Xiaowei, Xin Fu, Fengjiao Liu, Yanan Wang, Huangai Bi, and Xizhen Ai. "Hydrogen Sulfide Improves the Cold Stress Resistance through the CsARF5-CsDREB3 Module in Cucumber." International Journal of Molecular Sciences 22, no. 24 (December 8, 2021): 13229. http://dx.doi.org/10.3390/ijms222413229.

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As an important gas signaling molecule, hydrogen sulfide (H2S) plays a crucial role in regulating cold tolerance. H2S cooperates with phytohormones such as abscisic acid, ethylene, and salicylic acid to regulate the plant stress response. However, the synergistic regulation of H2S and auxin in the plant response to cold stress has not been reported. This study showed that sodium hydrosulfide (NaHS, an H2S donor) treatment enhanced the cold stress tolerance of cucumber seedlings and increased the level of auxin. CsARF5, a cucumber auxin response factor (ARF) gene, was isolated, and its role in regulating H2S-mediated cold stress tolerance was described. Transgenic cucumber leaves overexpressing CsARF5 were obtained. Physiological analysis indicated that overexpression of CsARF5 enhanced the cold stress tolerance of cucumber and the regulation of the cold stress response by CsARF5 depends on H2S. In addition, molecular assays showed that CsARF5 modulated cold stress response by directly activating the expression of the dehydration-responsive element-binding (DREB)/C-repeat binding factor (CBF) gene CsDREB3, which was identified as a positive regulator of cold stress. Taken together, the above results suggest that CsARF5 plays an important role in H2S-mediated cold stress in cucumber. These results shed light on the molecular mechanism by which H2S regulates cold stress response by mediating auxin signaling; this will provide insights for further studies on the molecular mechanism by which H2S regulates cold stress. The aim of this study was to explore the molecular mechanism of H2S regulating cold tolerance of cucumber seedlings and provide a theoretical basis for the further study of cucumber cultivation and environmental adaptability technology in winter.

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18

Stein, Tamar, Biswajit Bandyopadhyay, Tyler P. Troy, Yigang Fang, Oleg Kostko, Musahid Ahmed, and Martin Head-Gordon. "Ab initio dynamics and photoionization mass spectrometry reveal ion–molecule pathways from ionized acetylene clusters to benzene cation." Proceedings of the National Academy of Sciences 114, no. 21 (May 8, 2017): E4125—E4133. http://dx.doi.org/10.1073/pnas.1616464114.

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The growth mechanism of hydrocarbons in ionizing environments, such as the interstellar medium (ISM), and some combustion conditions remains incompletely understood. Ab initio molecular dynamics (AIMD) simulations and molecular beam vacuum-UV (VUV) photoionization mass spectrometry experiments were performed to understand the ion–molecule growth mechanism of small acetylene clusters (up to hexamers). A dramatic dependence of product distribution on the ionization conditions is demonstrated experimentally and understood from simulations. The products change from reactive fragmentation products in a higher temperature, higher density gas regime toward a very cold collision-free cluster regime that is dominated by products whose empirical formula is (C2H2)n+, just like ionized acetylene clusters. The fragmentation products result from reactive ion–molecule collisions in a comparatively higher pressure and temperature regime followed by unimolecular decomposition. The isolated ionized clusters display rich dynamics that contain bonded C4H4+ and C6H6+ structures solvated with one or more neutral acetylene molecules. Such species contain large amounts (>2 eV) of excess internal energy. The role of the solvent acetylene molecules is to affect the barrier crossing dynamics in the potential energy surface (PES) between (C2H2)n+ isomers and provide evaporative cooling to dissipate the excess internal energy and stabilize products including the aromatic ring of the benzene cation. Formation of the benzene cation is demonstrated in AIMD simulations of acetylene clusters with n > 3, as well as other metastable C6H6+ isomers. These results suggest a path for aromatic ring formation in cold acetylene-rich environments such as parts of the ISM.

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Öberg, Karin I., Edith C. Fayolle, John B. Reiter, and Claudia Cyganowski. "Complex molecule formation around massive young stellar objects." Faraday Discuss. 168 (2014): 81–101. http://dx.doi.org/10.1039/c3fd00146f.

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Interstellar complex organic molecules were first identified in the hot inner regions of massive young stellar objects (MYSOs), but have more recently been found in many colder sources, indicating that complex molecules can form at a range of temperatures. However, individually these observations provide limited constraints on how complex molecules form, and whether the same formation pathways dominate in cold, warm and hot environments. To address these questions, we use spatially resolved observations from the Submillimeter Array of three MYSOs together with mostly unresolved literature data to explore how molecular ratios depend on environmental parameters, especially temperature. Towards the three MYSOs, we find multiple complex organic emission peaks characterized by different molecular compositions and temperatures. In particular, CH₃CCH and CH₃CN seem to always trace a lukewarm (T ≈ 60 K) and a hot (T > 100 K) complex chemistry, respectively. These spatial trends are consistent with abundance–temperature correlations of four representative complex organics – CH₃CCH, CH₃CN, CH₃OCH₃ and CH₃CHO – in a large sample of complex molecule hosts mined from the literature. Together, these results indicate a general chemical evolution with temperature, i.e. that new complex molecule formation pathways are activated as a MYSO heats up. This is qualitatively consistent with model predictions. Furthermore, these results suggest that ratios of complex molecules may be developed into a powerful probe of the evolutionary stage of a MYSO, and may provide information about its formation history.

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Greenberg, James, O. A. Krohn, Jason A. Bossert, Yomay Shyur, David Macaluso, N. J. Fitch, and H. J. Lewandowski. "Velocity-tunable beam of continuously decelerated polar molecules for cold ion-molecule reaction studies." Review of Scientific Instruments 92, no. 10 (October 1, 2021): 103202. http://dx.doi.org/10.1063/5.0057859.

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21

Mişicu, Ş., A. Săndulescu, and W. Greiner. "Molecular Vibrational States in the Binary Cold Fission of 252Cf." Modern Physics Letters A 12, no. 18 (June 14, 1997): 1343–48. http://dx.doi.org/10.1142/s0217732397001357.

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We predict a molecular vibrational state in the cold binary fission of 252 Cf using a simple decay cluster model. The Hamiltonian of two even–even fragments in the pole–pole configuration is built in the same fashion as that for the dinuclear molecule formed in heavy-ions collisions. The interaction between the two fragments is described by the double-folding M3Y potential. The spectrum of the butterfly vibrations is derived and its dependence on fragments deformation and mass-asymmetry is discussed. Some experimental implications are commented.

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Wei, Bolin, Zhong Cao, and Bo Cui. "Atom-molecule conversion with quantum manipulations." Modern Physics Letters B 34, no. 30 (August 3, 2020): 2050337. http://dx.doi.org/10.1142/s0217984920503376.

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In this paper, we investigate quantum manipulations in an open atom-molecule conversion system. Through the transformation for the basis of the system, a set of time-dependent equations are derived under mean field approximation. We find that transitions between different dynamic areas of the system can be realized through manipulating an external rotating magnetic field, which corresponds to the tunneling rate in the equation. Through investigating the phase space of the system, we design an efficient method to combine pure cold molecule and pure molecular state so that it can be reached with much shorter time. Furthermore, manipulation of laser signal modulation, external diving and the distance-selective diffusion are also discussed in this paper.

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Kidera, Masanori, Kazuya Takahashi, Shuichi Enomoto, Akira Goto, and Yasushige Yano. "Letter: New Fragment Ion Production Method Using Super Cold Electrons in Electron Cyclotron Resonance Plasma." European Journal of Mass Spectrometry 13, no. 5 (October 2007): 355–58. http://dx.doi.org/10.1255/ejms.887.

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We examined the fragmentation and ionization of molecules by low-temperature electrons generated by electron cyclotron resonance (ECR) plasma. We examined several types of metallocene compounds comprising a metal and 1,3-cyclopentadienes as ligands. We performed analyses using an ECR ion source (ECRIS) mass spectrometer. Consequently, we succeeded in ionizing fragments of an organometallic compound by adjusting the input power of the microwave introducing a super high-frequency plasma. Moreover, we succeeded in dynamically generating a significant quantity of fragment ions by continuously varying the input power. Information on the structure of a molecule may be acquired from this operation. Moreover, a molecule that could not be easily ionized thus far may now be ionizable when soft ionization is performed with this technique.

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Lynch, D. K., L. S. Bernstein, and F. O. Clark. "Formation, Evolution and Destruction of Possible DIB Carriers: Dirty Molecular Hydrogen Ice Clusters." Proceedings of the International Astronomical Union 9, S297 (May 2013): 381–82. http://dx.doi.org/10.1017/s1743921313016177.

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AbstractWe suggest that the diffuse interstellar bands (DIBs) are absorption lines arising from electronic transitions in molecular clusters primarily composed of a single molecule, atom, or ion (“seed”), embedded in a single-layer shell of H2 molecules (Bernstein et al. 2013). We refer to these clusters as CHCs (Contaminated H2 Clusters). CHCs arise from cm-sized, dirty H2 ice balls, called CHIMPs (Contaminated H2 Ice Macro-Particles), formed in cold, dense, Giant Molecular Clouds (GMCs), and later released into the interstellar medium (ISM) upon GMC disruption. Absorption by the CHIMP of a UV photon releases CHCs. CHCs produce DIBs when they absorb optical photons. When this occurs, the absorbed photon energy disrupts the CHC.

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Saito, Toshiki, Shuro Takano, Nanase Harada, Taku Nakajima, Eva Schinnerer, Daizhong Liu, Akio Taniguchi, et al. "AGN-driven Cold Gas Outflow of NGC 1068 Characterized by Dissociation-sensitive Molecules." Astrophysical Journal 935, no. 2 (August 1, 2022): 155. http://dx.doi.org/10.3847/1538-4357/ac80ff.

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Abstract Recent developments in (sub)millimeter facilities have drastically changed the amount of information obtained from extragalactic spectral scans. In this paper, we present a feature extraction technique using principal component analysis (PCA) applied to arcsecond-resolution (1.″0–2.″0 = 72–144 pc) spectral scan data sets for the nearby type-2 Seyfert galaxy NGC 1068, using Band 3 of the Atacama Large Millimeter/submillimeter Array. We apply PCA to 16 well-detected molecular line intensity maps convolved to a common 150 pc resolution. In addition, we include the [S iii]/[S ii] line ratio and [C i] 3 P 1–3 P 0 maps in the literature, both of whose distributions show a remarkable resemblance to that of a kiloparsec-scale biconical outflow from the central active galactic nucleus. We identify two prominent features: (1) central concentration at the circumnuclear disk (CND) and (2) two peaks across the center that coincide with the biconical outflow peaks. The concentrated molecular lines in the CND are mostly high-dipole molecules (e.g., H13CN, HC3N, and HCN). Line emissions from molecules known to be enhanced in an irradiated interstellar medium, CN, C2H, and HNC, show similar concentrations and extended components along the bicone, suggesting that molecule dissociation is a dominant chemical effect of the cold molecular outflow of this galaxy. Although further investigation should be made, this scenario is consistent with the faintness or absence of emission lines from CO isotopologues, CH3OH, and N2H+ in the outflow, which are easily destroyed by dissociating photons and electrons.

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Doljikov, Yu S., A. L. Malinovsky, and E. A. Ryabov. "Inter- and Intramolecular Vibrational Distribution in IR Multiple Photon Excitation: CF2Cl2 Molecule." Laser Chemistry 8, no. 2-4 (January 1, 1988): 81–96. http://dx.doi.org/10.1155/lc.8.81.

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Vibrational energy distribution of IR MP-excited CF2Cl2 is studied when pumping molecules through ν1 and ν8 modes. In both cases the intermolecular distribution is found to be in a state of nonequilibrium consisting of ensembles of “hot” and “cold” molecules. The structure of the “cold” ensemble is different when ν1 and ν8 modes are pumped. Statistical intramolecular energy distribution caused by stochastization of vibrational motion is found for “hot” molecules. The estimated value of stochastization onset energy equals Eth ≤ 7800 cm−1.

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Agúndez, M., C. Cabezas, N. Marcelino, R. Fuentetaja, B. Tercero, P. de Vicente, and J. Cernicharo. "A new protonated molecule discovered in TMC-1: HCCNCH⁺." Astronomy & Astrophysics 659 (March 2022): L9. http://dx.doi.org/10.1051/0004-6361/202243396.

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In recent years we have seen an important increase in the number of protonated molecules detected in cold dense clouds. Here we report the detection in TMC-1 of HCCNCH+, the protonated form of HCCNC, which is a metastable isomer of HC3N. This is the first protonated form of a metastable isomer detected in a cold dense cloud. The detection was based on observations carried out with the Yebes 40 m telescope and the 30 m telescope of the Institut de Radioastronomie Millimétrique (IRAM), which revealed four harmonically related lines. We derived a rotational constant B = 4664.431891 ± 0.000692 MHz and a centrifugal distortion constant D = 519.14 ± 4.14 Hz. From a high level ab initio screening of potential carriers, we confidently assigned the series of lines to the ion HCCNCH+. We derived a column density of (3.0 ± 0.5) × 1010 cm−2 for HCCNCH+, which results in a HCCNCH+/HCCNC abundance ratio of 0.010 ± 0.002. This value is well reproduced by a state-of-the-art chemical model which, however, is subject to important uncertainties regarding the chemistry of HCCNCH+. The observational and theoretical status of protonated molecules in cold dense clouds indicate that there exists a global trend in which protonated-to-neutral abundance ratios MH+/M increase with increasing proton affinity of the neutral M, although if one is restricted to species M with high proton affinities (> 700 kJ mol−1), MH+/M ratios fall in the range 10−3–10−1, with no apparent correlation with the proton affinity. We suggest various protonated molecules that are good candidates for detection in cold dense clouds in the near future.

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Basalgète, R., R. Dupuy, G. Féraud, C. Romanzin, L. Philippe, X. Michaut, J. Michoud, et al. "Complex organic molecules in protoplanetary disks: X-ray photodesorption from methanol-containing ices." Astronomy & Astrophysics 647 (March 2021): A36. http://dx.doi.org/10.1051/0004-6361/202040117.

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Context. Astrophysical observations show complex organic molecules (COMs) in the gas phase of protoplanetary disks. X-rays emitted from the central young stellar object (YSO) that irradiate interstellar ices in the disk, followed by the ejection of molecules in the gas phase, are a possible route to explain the abundances observed in the cold regions. This process, known as X-ray photodesorption, needs to be quantified for methanol-containing ices. Aims. We aim at experimentally measuring X-ray photodesorption yields (in molecule desorbed per incident photon, displayed as molecule/photon for more simplicity) of methanol and its photo-products from binary mixed ices: 13CO:CH3OH ice and H2O:CH3OH ice. Methods. We irradiated these ices at 15 K with X-rays in the 525–570 eV range from the SEXTANTS beam line of the SOLEIL synchrotron facility. The release of species in the gas phase was monitored by quadrupole mass spectrometry, and photodesorption yields were derived. Results. For 13CO:CH3OH ice, CH3OH X-ray photodesorption yield is estimated to be ∼10−2 molecule/photon at 564 eV. X-ray photodesorption of larger COMs, which can be attributed to either ethanol, dimethyl ether, and/or formic acid, is detected with a yield of ∼10−3 molecule/photon. When methanol is mixed with water, X-ray photodesorption of methanol and of the previous COMs is not detected. X-ray induced chemistry, dominated by low-energy secondary electrons, is found to be the main mechanism that explains these results. We also provide desorption yields that are applicable to protoplanetary disk environments for astrochemical models. Conclusions. The X-ray emission from YSOs should participate in the enrichment of the protoplanetary disk gas phase with COMs such as methanol in the cold and X-ray dominated regions because of X-ray photodesorption from methanol-containing ices.

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Hirano, Yu, Kana Tsukamoto, Shingo Ariki, Yuki Naka, Mitsuhiro Ueda, and Taro Tamada. "X-ray crystallographic structural studies of α-amylase I from Eisenia fetida." Acta Crystallographica Section D Structural Biology 76, no. 9 (August 25, 2020): 834–44. http://dx.doi.org/10.1107/s2059798320010165.

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The earthworm Eisenia fetida possesses several cold-active enzymes, including α-amylase, β-glucanase and β-mannanase. E. fetida possesses two isoforms of α-amylase (Ef-Amy I and II) to digest raw starch. Ef-Amy I retains its catalytic activity at temperatures below 10°C. To identify the molecular properties of Ef-Amy I, X-ray crystal structures were determined of the wild type and of the inactive E249Q mutant. Ef-Amy I has structural similarities to mammalian α-amylases, including the porcine pancreatic and human pancreatic α-amylases. Structural comparisons of the overall structures as well as of the Ca2+-binding sites of Ef-Amy I and the mammalian α-amylases indicate that Ef-Amy I has increased structural flexibility and more solvent-exposed acidic residues. These structural features of Ef-Amy I may contribute to its observed catalytic activity at low temperatures, as many cold-adapted enzymes have similar structural properties. The structure of the substrate complex of the inactive mutant of Ef-Amy I shows that a maltohexaose molecule is bound in the active site and a maltotetraose molecule is bound in the cleft between the N- and C-terminal domains. The recognition of substrate molecules by Ef-Amy I exhibits some differences from that observed in structures of human pancreatic α-amylase. This result provides insights into the structural modulation of the recognition of substrates and inhibitors.

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Balachandrakumar, K., V. Raja, B. Karthikeyan, S. P. Bagare, and N. Rajamanickam. "Evaluation of the Effective Temperature of Sunspots Using Molecular Parameters of AlF." Advances in Astronomy 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/846840.

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The physical conditions of celestial objects can be analyzed using the spectrum of atoms or molecules present in the object. The present work focuses on the spectroscopic analysis of astrophysically significant molecule AlF. The evaluation of Franck-Condon (FC) factors andr-centroids is done by a numerical integration procedure using the suitable potential energy curves forC1Σ+-A1Σ+,b3Σ+-a3Πr,c3Σ-a3Πr, andf3Π-a3Πrband systems of AlF molecule. The intensity of various bands is discussed with the help of derived FC factors. The band degradation and the nature of potential energy curves are studied usingr-centroid values. The vibrational temperature of sunspot is estimated to be around 1220 ± 130 K which falls in the reported temperature range of cold sunspots.

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Santamaria, Luigi, Valentina Di Sarno, Roberto Aiello, Maurizio De Rosa, Iolanda Ricciardi, Paolo De Natale, and Pasquale Maddaloni. "Infrared Comb Spectroscopy of Buffer-Gas-Cooled Molecules: Toward Absolute Frequency Metrology of Cold Acetylene." International Journal of Molecular Sciences 22, no. 1 (December 29, 2020): 250. http://dx.doi.org/10.3390/ijms22010250.

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We review the recent developments in precision ro-vibrational spectroscopy of buffer-gas-cooled neutral molecules, obtained using infrared frequency combs either as direct probe sources or as ultra-accurate optical rulers. In particular, we show how coherent broadband spectroscopy of complex molecules especially benefits from drastic simplification of the spectra brought about by cooling of internal temperatures. Moreover, cooling the translational motion allows longer light-molecule interaction times and hence reduced transit-time broadening effects, crucial for high-precision spectroscopy on simple molecules. In this respect, we report on the progress of absolute frequency metrology experiments with buffer-gas-cooled molecules, focusing on the advanced technologies that led to record measurements with acetylene. Finally, we briefly discuss the prospects for further improving the ultimate accuracy of the spectroscopic frequency measurement.

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Hu, Rui, Qiuju Han, and Jian Zhang. "STAT3: A key signaling molecule for converting cold to hot tumors." Cancer Letters 489 (October 2020): 29–40. http://dx.doi.org/10.1016/j.canlet.2020.05.035.

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Rivilla, Víctor M., Francesco Fontani, Maite Beltrán, Anton Vasyunin, Paola Caselli, Jesús Martín-Pintado, and Riccardo Cesaroni. "The first detections of the key prebiotic molecule PO in star-forming regions." Proceedings of the International Astronomical Union 13, S332 (March 2017): 409–14. http://dx.doi.org/10.1017/s1743921317008729.

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AbstractPhosphorus is a crucial element in prebiotic chemistry, especially the P−O bond, which is key for the formation of the backbone of the deoxyribonucleic acid. So far, PO had only been detected towards the envelope of evolved stars, and never towards star-forming regions. We report the first detection of PO towards two massive star-forming regions, W51 e1/e2 and W3(OH), using data from the IRAM 30m telescope. PN has also been detected towards the two regions. The abundance ratio PO/PN is 1.8 and 3 for W51 and W3(OH), respectively. Our chemical model indicates that the two molecules are chemically related and are formed via gas-phase ion-molecule and neutral-neutral reactions during the cold collapse. The molecules freeze out onto grains at the end of the collapse and desorb during the warm-up phase once the temperature reaches ~35 K. The observed molecular abundances of 10−10 are predicted by the model if a relatively high initial abundance of 5× 10−9 of initial phosphorus is assumed.

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Pitzer, Martin, Maksim Kunitski, Allan S. Johnson, Till Jahnke, Hendrik Sann, Felix Sturm, Lothar Ph H. Schmidt, et al. "Direct Determination of Absolute Molecular Stereochemistry in Gas Phase by Coulomb Explosion Imaging." Science 341, no. 6150 (September 5, 2013): 1096–100. http://dx.doi.org/10.1126/science.1240362.

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Bijvoet’s method, which makes use of anomalous x-ray diffraction or dispersion, is the standard means of directly determining the absolute (stereochemical) configuration of molecules, but it requires crystalline samples and often proves challenging in structures exclusively comprising light atoms. Herein, we demonstrate a mass spectrometry approach that directly images the absolute configuration of individual molecules in the gas phase by cold target recoil ion momentum spectroscopy after laser ionization–induced Coulomb explosion. This technique is applied to the prototypical chiral molecule bromochlorofluoromethane and the isotopically chiral methane derivative bromodichloromethane.

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Fortenberry, Ryan C., and Laurent Wiesenfeld. "A Molecular Candle Where Few Molecules Shine: HeHHe+." Molecules 25, no. 9 (May 7, 2020): 2183. http://dx.doi.org/10.3390/molecules25092183.

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HeHHe + is the only potential molecule comprised of atoms present in the early universe that is also easily observable in the infrared. This molecule has been known to exist in mass spectrometry experiments for nearly half-a-century and is likely present, but as-of-yet unconfirmed, in cold plasmas. There can exist only a handful of plausible primordial molecules in the epochs before metals (elements with nuclei heavier than 4 He as astronomers call them) were synthesized in the universe, and most of these are both rotationally and vibrationally dark. The current work brings HeHHe + into the discussion as a possible (and potentially only) molecular candle for probing high-z and any metal-deprived regions due to its exceptionally bright infrared feature previously predicted to lie at 7.43 μ m. Furthermore, the present study provides new insights into its possible formation mechanisms as well as marked stability, along with the decisive role of anharmonic zero-point energies. A new entrance pathway is proposed through the triplet state ( 3 B 1 ) of the He 2 H + molecule complexed with a hydrogen atom and a subsequent 10.90 eV charge transfer/photon emission into the linear and vibrationally-bright 1 Σ g + HeHHe + form.

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Chalasti, Maria, Christos Iordanou, Zisis Kratiras, Aikaterini Stylianaki, Eleni-Andriana Trigka, Eleftheria Lakiotaki, Kali Makedou, et al. "Experimental isolation and preservation of solid organs before transplantation: effects of pretreatment using four different molecules." Journal of International Medical Research 48, no. 6 (June 2020): 030006052093345. http://dx.doi.org/10.1177/0300060520933452.

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Objectives In transplantation surgery, the ischaemic organ and reperfusion impairment after cold storage remains a considerable risk factor for impaired function and potential failure of the grafted organ. Substantial logistical efforts have been undertaken to reduce the cold ischaemic time because the demand for available transplant organs and the periods of cold ischaemia are increasing. Methods Four molecules were investigated (erythropoietin, sildenafil, lazaroid [U74389G], octreotide) in individual intravenous infusions 1 hour before the organ was harvested. This study was performed in 30 healthy landrace/large-white pigs (male; >10 weeks old; average weight, 22 ± 2 kg) in groups of six. The organs were studied at harvest, and at 8 and 24 hours post-harvest. Results The lazaroid molecule increased malondialdehyde (MDA) levels in the liver and pancreas at 8 hours. Hepatic lazaroid molecules improved liver histology at 8 and 24 hours. For kidneys, erythropoietin had a positive effect at 24 hours post-harvest. For the pancreas, octreotide showed better performance. In the lungs, there was less interstitial oedema with erythropoietin and lazaroid compared with the control group at 8 hours post-harvest. Conclusion All molecules had a positive effect and decreased ischaemia/reperfusion graft injury. Thus, pretreatment before organ harvest has a beneficial role.

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Yuri S. Akishev, Yuri S. "NON-THERMAL PLASMA AT ATMOSPHERIC PRESSURE AND ITS OPPORTUNITIES FOR APPLICATIONS." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 62, no. 8 (August 19, 2019): 26–60. http://dx.doi.org/10.6060/ivkkt.20196208.5908.

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The subject of this review is the low-temperature (or "cold") weakly-ionized but strongly non-equilibrium plasma created at atmospheric pressure in gaseous mixtures or directly in atmospheric air. Cold plasma is rather new, but very perspective object. The strong non-equilibrium of the weakly-ionized plasma leads to that energetic electrons despite their small quantity very effectively excite and dissociate the neutral particles which are contained in surrounding gas, for example, of a molecule of oxygen and water. The pointed above property of cold plasma is valuable from the practical point of view because it allows creating in plasma-forming gas rather intensive ultra-violet radiation and high concentration of physically and biochemically reactive species (metastable atoms and molecules, radicals, ozone, and others) with rather small specific energy consumption. Now the usage of cold plasma at atmospheric pressure gives the opportunity to solve many practical problems which were earlier seeming unsolvable. It is possible even to claim that the approaches based on the use of cold plasma in dense gases define modern progress in many fields of science, biomedicine and, in particular, in the field of chemical technology. The review of modern experimental methods of creation of the cold plasma at atmospheric pressure is given. Physical and chemical features of cold plasma in dense gases have been considered. Special attention is paid to the kinetics of the charged particles in non-equilibrium plasma and the vibrationally excited molecules as well. Additionally, the kinetics of the electronic excited and metastable states is taken into account because they also influence a biochemical activity of low-temperature plasma. A lot of places is given to concrete examples of the modern practical use of such plasma in ecology for the destruction of the low-concentrated harmful organic and inorganic impurities in the exhausted airflows at atmospheric pressure.

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Chaabouni, Henda, Saoud Baouche, Stephan Diana, and Marco Minissale. "Reactivity of formic acid (HCOOH) with H atoms on cold surfaces of interstellar interest." Astronomy & Astrophysics 636 (April 2020): A4. http://dx.doi.org/10.1051/0004-6361/201936411.

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Context. Formic acid (HCOOH) is the simplest organic carboxylic acid in chemical synthesis and the significant species in interstellar chemistry. HCOOH has been abundantly detected in interstellar ices, dense molecular clouds and star-forming regions. Aims. Laboratory hydrogenation experiments of HCOOH molecules with H atoms were performed with two cryogenic ultra-high vacuum devices on amorphous solid water ices, and highly oriented pyrolytic graphite surfaces. The aim of this work is to study the reactivity of HCOOH molecules with H atoms at low surface temperature 10 K, low surface coverage of one monolayer to three layers, and low H-atom flux of about 3.0 × 1012 molecule cm−2 s−1. Methods. HCOOH and H beams were deposited on cold surfaces held at 10 K, and the condensed films were analyzed by in-situ Reflection Absorption InfraRed Spectroscopy and temperature programmed desorption (TPD) mass spectrometry technique by heating the sample from 10 to 200 K. Results. Using the temperature programmed during exposure desorption technique, we highlight the possible dimerization of HCOOH molecules at low surface temperatures between 10 and 100 K. In our HCOOH+H experiments, we evaluated a consumption of 20–30% of formic acid by comparing the TPD curves at m/z 46 of pure and H-exposed HCOOH ice. Conclusions. The hydrogenation HCOOH+H reaction is efficient at low surface temperatures. The main products identified experimentally are carbon dioxide (CO2) and water (H2O) molecules. CO bearing species CH3OH, and H2CO are also detected mainly on graphite surfaces. A chemical surface reaction route for the HCOOH+H system is proposed to explain the product formation.

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Chen, Su, Yang Liu, Yanan Zhou, Lan He, and Jin Ouyang. "Mechanism study on the abnormal accumulation and deposition of islet amyloid polypeptide by cold-spray ionization mass spectrometry." Analyst 145, no. 22 (2020): 7289–96. http://dx.doi.org/10.1039/d0an01034k.

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Muller, D., K. Pederson, R. Murray, and J. A. Frelinger. "A single amino acid substitution in an MHC class I molecule allows heteroclitic recognition by lymphocytic choriomeningitis virus-specific cytotoxic T lymphocytes." Journal of Immunology 147, no. 4 (August 15, 1991): 1392–97. http://dx.doi.org/10.4049/jimmunol.147.4.1392.

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Abstract Class I molecules of the MHC bind foreign and endogenous peptides allowing recognition by the TCR on CTL. The recognition and killing of cells infected with lymphocytic choriomeningitis virus (LCMV) depends on the recognition of LCMV peptides bound to class I MHC. Mutations in class I MHC molecules have enabled the delineation of regions in the class I molecule important for binding peptides and for interaction with the TCR. We have constructed a library of class I mutants using saturation mutagenesis and report a phenotypic change resulting from a single amino acid substitution that results in the heteroclitic (increased) killing of LCMV-infected cells. This amino acid change, asparagine to serine at position 30, is in a conserved region of the class I molecule contacting the alpha 3 domain. This mutation does not result in increased expression of the class I molecule on the cell surface, does not affect the binding of CD8, and does not affect allogeneic recognition. Cold target experiments show that this heteroclitic killing is due to increased recognition by CTL. These data point toward a critical function for this region of the class I molecule in the binding of peptides or their presentation to CTL.

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Eccles, Ronald. "Iota-Carrageenan as an Antiviral Treatment for the Common Cold." Open Virology Journal 14, no. 1 (May 4, 2020): 9–15. http://dx.doi.org/10.2174/1874357902014010009.

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Introduction: The common cold syndrome of acute upper respiratory tract viral infection is the most common disease among mankind and is an extremely common illness in children. There is a great need for a safe and effective antiviral treatment with minimal side effects. The challenge in developing a treatment is the numerous and varied respiratory viruses that cause this common illness and the need for a treatment with good tolerability and safety. Explanation: All respiratory viruses must reach the cell surface by passing through respiratory fluid and mucus, and this common feature may allow for the development of antivirals that capture viruses during this transit. This article discusses how large polyanionic molecules such as iota-carrageenan may trap positively charged respiratory viruses. Iota-carrageenan is a large polysaccharide molecule which is neither absorbed from the respiratory tract nor metabolised. It, therefore, does not have any pharmacological properties. Iota-carrageenan nasal spray has been shown to reduce the titres of respiratory viruses and to reduce the severity of symptoms in placebo-controlled clinical trials, including children and adults. The results of four clinical trials are presented. Conclusion: Iota-carrageenan is a good candidate as a safe and effective non-specific antiviral treatment for common cold, and more research is justified on polyanionic molecules like carrageenans as antivirals.

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Alonso-Herrero, A., M. Pereira-Santaella, D. Rigopoulou, I. García-Bernete, S. García-Burillo, A. J. Domínguez-Fernández, F. Combes, et al. "Cold molecular gas and PAH emission in the nuclear and circumnuclear regions of Seyfert galaxies." Astronomy & Astrophysics 639 (July 2020): A43. http://dx.doi.org/10.1051/0004-6361/202037642.

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We investigate the relation between the detection of the 11.3 μm polycyclic aromatic hydrocarbon (PAH) feature in the nuclear (∼24−230 pc) regions of 22 nearby Seyfert galaxies and the properties of the cold molecular gas. For the former we use ground-based (0.3−0.6″ resolution) mid-infrared (mid-IR) spectroscopy. The cold molecular gas is traced by ALMA and NOEMA high (0.2−1.1″) angular resolution observations of the CO(2–1) transition. Galaxies with a nuclear detection of the 11.3 μm PAH feature contain more cold molecular gas (median 1.6 × 107 M⊙) and have higher column densities (N(H2) = 2 × 1023 cm−2) over the regions sampled by the mid-IR slits than those without a detection. This suggests that molecular gas plays a role in shielding the PAH molecules in the harsh environments of Seyfert nuclei. Choosing the PAH molecule naphthalene as an illustration, we compute its half-life in the nuclear regions of our sample when exposed to 2.5 keV hard X-ray photons. We estimate shorter half-lives for naphthalene in nuclei without a 11.3 μm PAH detection than in those with a detection. The Spitzer/IRS PAH ratios on circumnuclear scales (∼4″ ∼ 0.25−1.3 kpc) are in between model predictions for neutral and partly ionized PAHs. However, Seyfert galaxies in our sample with the highest nuclear H2 column densities are not generally closer to the neutral PAH tracks. This is because in the majority of our sample galaxies, the CO(2–1) emission in the inner ∼4″ is not centrally peaked and in some galaxies traces circumnuclear sites of strong star formation activity. Spatially resolved observations with the MIRI medium-resolution spectrograph on the James Webb Space Telescope will be able to distinguish the effects of an active galactic nucleus (AGN) and star formation on the PAH emission in nearby AGN.

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Дмитриев, Ю. А. "Анизотропное насыщение спектра ЭПР радикала DCO, стабилизированного в твердом CO при 4.2 K, и его ориентационное движение." Оптика и спектроскопия 130, no. 12 (2022): 1803. http://dx.doi.org/10.21883/os.2022.12.54084.3712-22.

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Formyl radicals, DCO, were produced in solid CO matrix and studied by EPR using gas deposition technique on a cold substrate at 4.2 K. The radical electron spin-lattice relaxation was measured to be anisotropic. The anisotropy was found to originate from the anisotropic orientational motion of the radical with the most intensive librations performed around a z axis corresponding to the smallest moment of inertia of the molecule. It was shown that, in solid CO, the libration motion of small molecules is modeled by considering a particle rotating in the orientational potential box. A suggestion was substantiated about the complicated nature of the orientational motion of HCO in the solid CO matrix including the intensive librations and slow tunneling rotation of the molecule around the z axis.

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BUETTNER, DOUGLAS J., P. D. MORLEY, and IVAN SCHMIDT. "SEARCHING FOR EXTRA DIMENSIONS IN THE EARLY UNIVERSE." International Journal of Modern Physics A 19, no. 25 (October 10, 2004): 4201–5. http://dx.doi.org/10.1142/s0217751x04019925.

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We investigate extra spatial dimensions (D=3+∊) in the early universe using very high resolution molecular rotational spectroscopic data derived from a large molecular cloud containing moderately cold carbon monoxide gas at Z≈6.42. It turns out that the ∊-dependent quantum mechanical wavelength transitions are solvable for a linear molecule and we present the solution here. The CO microwave data allows a very precise determination of <∊>=-0.00000657±0.10003032. The probability that <∊>≠0 is one in 7794, only 850 million years (using the standard cosmology) after the Big Bang.

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Azizbekyan, H. H. "An ansatz for the nonlinear Demkov-Kunike problem for cold molecule formation." Journal of Contemporary Physics (Armenian Academy of Sciences) 45, no. 3 (April 30, 2010): 104–10. http://dx.doi.org/10.3103/s1068337210030023.

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Aymar, M., O. Dulieu, and F. Spiegelman. "Electronic properties of francium diatomic compounds and prospects for cold molecule formation." Journal of Physics B: Atomic, Molecular and Optical Physics 39, no. 19 (September 25, 2006): S905—S927. http://dx.doi.org/10.1088/0953-4075/39/19/s07.

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Lepers, M., and O. Dulieu. "Cold atom-molecule photoassociation: long-range interactions beyond the 1/Rn expansion." European Physical Journal D 65, no. 1-2 (May 17, 2011): 113–23. http://dx.doi.org/10.1140/epjd/e2011-20083-6.

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Ligterink, N. F. W., C. Walsh, R. G. Bhuin, S. Vissapragada, J. Terwisscha van Scheltinga, and H. Linnartz. "Methanol ice co-desorption as a mechanism to explain cold methanol in the gas-phase." Astronomy & Astrophysics 612 (April 2018): A88. http://dx.doi.org/10.1051/0004-6361/201731893.

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Context. Methanol is formed via surface reactions on icy dust grains. Methanol is also detected in the gas-phase at temperatures below its thermal desorption temperature and at levels higher than can be explained by pure gas-phase chemistry. The process that controls the transition from solid state to gas-phase methanol in cold environments is not understood. Aims. The goal of this work is to investigate whether thermal CO desorption provides an indirect pathway for methanol to co-desorb at low temperatures. Methods. Mixed CH3OH:CO/CH4 ices were heated under ultra-high vacuum conditions and ice contents are traced using RAIRS (reflection absorption IR spectroscopy), while desorbing species were detected mass spectrometrically. An updated gas-grain chemical network was used to test the impact of the results of these experiments. The physical model used is applicable for TW Hya, a protoplanetary disk in which cold gas-phase methanol has recently been detected. Results. Methanol release together with thermal CO desorption is found to be an ineffective process in the experiments, resulting in an upper limit of ≤ 7.3 × 10−7 CH3OH molecules per CO molecule over all ice mixtures considered. Chemical modelling based on the upper limits shows that co-desorption rates as low as 10−6 CH3OH molecules per CO molecule are high enough to release substantial amounts of methanol to the gas-phase at and around the location of the CO thermal desorption front in a protoplanetary disk. The impact of thermal co-desorption of CH3OH with CO as a grain-gas bridge mechanism is compared with that of UV induced photodesorption and chemisorption.

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Sarkar, M., D. Mitra, and A. K. Sen. "Studies on chemical modification of cold agglutinin from the snail Achatina fulica." Biochemical Journal 246, no. 1 (August 15, 1987): 157–61. http://dx.doi.org/10.1042/bj2460157.

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The cold agglutinin isolated from the albumin gland of the snail Achatina fulica was modified with various chemical reagents in order to detect the amino acids and/or carbohydrate residues present in its carbohydrate-binding sites. Treatment with reagents considered specific for modification of lysine, arginine and tryptophan residues of the cold agglutinin did not affect the carbohydrate-binding activity of the agglutinin. Modification of tyrosine residues showed some change. However, modification with carbodiimide followed by α-aminobutyric acid methyl ester causes almost complete loss of its binding activity, indicating the involvement of aspartic acid and glutamic acid in its carbohydrate-binding activity. The carbohydrate residues of the cold agglutinin were removed by beta-elimination reaction, indicating that the sugars are O-glycosidically linked to protein part of the molecule. Removal of galactose residues from the cold agglutinin by the action of beta-galactosidase indicated that the galactose molecules are beta-linked. These carbohydrate-modified glycoproteins showed a marked change in agglutination property, i.e. they agglutinated rabbit erythrocytes at both 10 degrees C and 25 degrees C, indicating that the galactose residues of the glycoprotein play an important role in the cold-agglutination property of the glycoprotein. The c.d. data showed the presence of an almost identical type of random-coil conformation in the native cold agglutinin at 10 degrees C and in the carbohydrate-modified glycoprotein at 10 degrees C and 25 degrees C. This particular random-coil conformation is essential for carbohydrate-binding property of the agglutinin.

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Poturay, V. A. "ORGANIC MATTER IN THERMAL, COLD GROUND AND SURFACE WATERS OF THE FAR EAST SOUTH CONTINENTAL PART (OXYGEN-CONTAINING COMPOUNDS)." REGIONAL PROBLEM 24, no. 4 (2021): 50–62. http://dx.doi.org/10.31433/2618-9593-2021-24-4-50-62.

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This article presents the composition and molecular weight distribution of medium volatility oxygen-containing organic compounds in the thermal, cold ground and surface waters of the continental part of the Far East south. Using the method of capillary gas chromatography-mass spectrometry, it is found 71 oxygen-containing compounds in thermal waters, belonging to 10 homologous series, and in cold ground and surface waters – 36 compounds, belonging to 7 homologous series. Their relative content in the medium volatility organic matter composition is about 55% in thermal waters and about 45% in cold ground and surface waters. Esters, carboxylic acids and aldehydes are widespread in hot waters. These compounds are widely produced in the biosphere and are probably of biogenic origin. The features of the carboxylic acids and aldehydes molecular weight distribution (the predominance of homologues with an even number of carbon atoms in the molecule) also show their biogenic genesis. The formation of ethers can as well be associated with the oxidation of organic matter in water-bearing rocks, and aromatic and nitrogen-containing components – with thermogenic processes occurring in hydrothermal systems. Esters, steroids and ketones also reach their maximum relative concentrations in cold waters. Steroids predominate in the oxygen-containing organic compounds composition in cold ground and surface waters where the carboxylic acids distribution is insignificant. Among the revealed compounds, in thermal waters there are some components – indicators of technogenic pollution. These are the compounds containing a tert-butyl group and DETA. However, their share in the composition of medium volatility organic matter is insignificant.

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Journal articles on the topic 'Cold Molecule'

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