Structural features of an acidic polysaccharide with the potential of promoting osteoblast differentiation from Lycium ruthenicum Murr.

Abstract

The enhanced osteoblast differentiation is beneficial to the prevention of osteoporosis. In this study, a homogeneous polysaccharide (LRP-S2A) with the potential of promoting osteoblast differentiation was obtained from the fruits of Lycium ruthenicum, a traditional herb for treatment of postmenopausal metabolic disorders. Structural identification indicated that LRP-S2A, with a relative molecular weight of 2.65 × 10⁶ Da and an uronic acid content of 41.8%, contained Rha, Ara, Gal, Glc and GlcA in a molar ratio of 1.00 : 2.07 : 0.57 : 2.59 : 4.33 and was composed of a backbone consisting of 6-O-Me-α-(1→4)-D-GlcpA, 2-O-acetyl-α-(1→4)-D-Glcp, α-(1→2,4)-L-Rhap, β-(1→3)-D-Galp andα-(1→3,5)-L-Araf, and some branches consisting of 6-O-Me-α-(1→4)-D-GlcpA and terminal α-L-Araf. These results suggested that LRP-S2A with the potential of promoting osteoblast differentiation was a new acidic polysaccharide.     

Structure Studies of the Extracellular Polysaccharide from <Emphasis Type="Italic">Trichoderma</Emphasis> sp. KK19L1 and Its Antitumor Effect via Cell Cycle Arrest and Apoptosis

An extracellular polysaccharide TP1A was purified from the fermented broth of Trichoderma sp. KK19L1 by combination of Q Sepharose fast flow and Sephacryl S-300 chromatography. TP1A was composed of Man, Gal, and Glc in a molar ratio of about 3.0:5.1:8.1. The molar mass of TP1A was about 40.0 kDa. Methylation and NMR analysis indicated that the probable structure of TP1A was [→4,6)-α-D-Glcp(1→6)-β-D-Galf(1→6)-β-D-Galf(1→2,6)-β-D-Galf(1→2,6)-β-D-Galf(1→2,6)-β-D-Galf(1→2,6)-α-D-Manp(1→2,6)-α-D-Manp(1→] with [α-D-Glcp(1→] and [α-D-Manp(1→6)-α-D-Glcp(1→6)-α-D-Glcp(1→] as branches. The antitumor study showed that TP1A was able to inhibit the cell viability of HeLa and MCF-7 cells. TP1A could arrest HeLa cells in G2/M phase and induce HeLa cell apoptosis. These findings suggest that fungal polysaccharides could be a potential source for antitumor agents.     

Structure analysis and anti-fatigue activity of a polysaccharide from Lepidium meyenii Walp

A polysaccharide was obtained from Lepidium meyenii Walp by hot water extraction and purification by Millipore (100 kD) and Sephadex G-200. The content of polysaccharide was examined to be 89.9% with phenol-sulfuric acid method. Its average molecular weight was estimated to be 2.213 × 10⁶ Da by High Performance Gel Permeation Chromatography (HPGPC). Monosaccharide analysis showed that the polysaccharide was composed of arabinose, mannose, glucose and galactose with the molar ratio of 2.134: 1: 2.78: 2.82. After Smith degradation, methylation, infrared spectroscopy and NMR, the primary structure of the polysaccharide was identified. The backbone of the polysaccharide was composed of →4)-β-D-Galp-(1→ and →4)-α-D-Galp-(1→, while the branches were comprised of →6)-β-D-Glup-(1→, →5)- β-D-Araf-(1→, →3,6)-α-D-Manp-(1→, →3)-α-D-Galp-(1→, and α-D-Glup-(1→. The anti-fatigue effect of the polysaccharide was evaluated using exhaustive swimming test and biochemical indexes. The results indicated the polysaccharide has anti-fatigue effect.     

Studies on the Solution Conformation and Dynamics of the Trisaccharide Repeating Unit of the Kps from Sinorhizobium Fredii Svq293

ABSTRACT

The conformational behaviour of the major trisaccharide repeating unit (α-D-Galp-(1→2)-β-D-Ribf-(1→9)-α-5-O-Me-Kdnp-) of the polysaccharide from Sinorhizobium fredii SVQ293, a mutant derivative has been analysed by NMR spectroscopy and extensive molecular dynamics simulations. The results obtained indicate that the five-membered ring adopts an almost unique conformation as do the pyranose rings. The Ribf-(1→9)-α-5-O-Me-Kdnp linkage may adopt a variety of conformations while the α-D-Galp-(1→2)-β-D-Ribf- also populates an extended surface of the Φ/Ψ map. Two 10 ns MD simulations using the GB/SA continuum solvent model for water and the MM3* force field provides a population distribution of conformers which satisfactorily agrees with the experimental NMR data for both the glycosidic linkages and the hydroxymethyl groups.     

Isolation and structural characterization of a low-molecular-weight pectic polysaccharide SHPPB-1 isolated from sunflower heads

A novel low-molecular-weight pectic polysaccharide was isolated from sunflower heads that are a useless side product produced from sunflower oil processing. The low-molecular-weight pectic polysaccharide was purified by using an optimized four-step procedure and named as SHPPB-1. The molecular weight of SHPPB-1 is about 1.69× 10⁴ Da. Structure characterizations of SHPPB-1 by monosaccharide composition, methylation analysis, and Fourier transform infrared (FT-IR) spectroscopy showed that SHPPB-1 is consisted of 1,4-linked α-D-GalpA and 1,4-linked 2-OAc-5-COOMe-α-D-GalpA with rare α/β-D-Rhap, α/β-D-Manp, and α/β-D-GalpA. This was combined with NMR spectroscopic analysis to propose a structure of SHPPB-1 as: →4)-[α/β-D-monosaccharide-(1→3)]-α-D-GalpA-(1→4)-2-OAc-5-COOMe-α-D-GalpA-(1→ .     

Triterpene glycosides of Hedera taurica

From the leaves of Crimean ivy we have isolated the previously known glycosides 3-O-α-L-Ara_p-28-O-[O-α-L-Rha_p-(1→4)-O-β-D-Glc_p-(1→6)-β-D-Glc_p]hederagenin, 3-O-[O-α-L-Rha_p-(1→2)-α-L-Ara_p]-28-O-[O-α-L-Rha_p-(1→4)-O-β-D-Glc_p-(1→6)-β-D-Glc_p]oleanic acid and -hederagenin, and 3-O-[O-α-L-Rha_p-(1→2)-α-L-Ara_p]-28-O-[O-β-D-Glc_p-(1→6)-β-D-Glc_p]hederagenin and a new one: tauroside H₁ — 3-O-[O-α-L-Rha_p-(1→2)-O-α-L-Ara_p]-28-O-[O-α-L-Rha_p-(1→4)-O-β-D-Glc_p-(1→6)-β-D-Glc_p]echinocystic acid.     

Synthesis of oligosaccharides as potential novel food components and upscaled enzymatic reaction employing the β-galactosidase from bovine testes

The β-galactosidase from bovine testes (EC 3.2.1.23) promotes the transfer of a galactose unit to glucose or galactose-containing residues in manifold derivatives, establishing β1→3 linkages.The synthesis of several potentially biologically important oligosaccharides β-d-Galp-(1→3)-α-d-Glcp-(1→2)-β-d-Fruf2, β-d-Galp-(1→3)-β-d-Galp-(1→4)-α,β-d-Glcp4, β-d-Galp-(1→3)-α-d-Glcp-(1→4)-d-Glcp-ol/Manp-ol 6, β-d-Galp-(1→3)-α-d-Glcp-(1→6)-β-d-Fruf8, β-d-Galp-(1→3)-α-d-Glcp-(1→6)-[α-d-Glcp-(1↔2)]-β-d-Fruf10, α-d-Galp-(1→6)-[β-d-Galp-(1→3)]-α-d-Glcp-(1↔2)-β-d-Fruf12, β-d-Galp-(1→3)-α-d-Glcp-(1↔2)-β-d-Fruf-(1↔2)-β-d-Fruf14 has been reached in yields between 7 and 44% by implementation of this specific enzyme. In addition, we found that it is feasible to gain high yields without an enzyme-specific buffer and even making upscaled preparation on a gram scale.     

Application of a laser produced plasma: Experimental Stark widths of single ionized lead lines

The optical emission spectroscopy from laser produced plasma generated by a 10,640 Å radiation, with an irradiance of 1.4 × 10¹⁰ W cm^− 2 on several lead targets, in vacuum and in an atmosphere of argon, was recorded and analyzed between 1900 and 7000 Å. The Local Thermodynamic Equilibrium conditions and plasma homogeneity have been checked. Stark widths for 31 lines of Pb II have been measured. These lines measured in this work correspond to the transitions 7s → 6p, n(n = 8, 9, 10)s → 7p, n(n = 7, 8)p → 7s, n(n = 7, 8)p → 6p², n(n = 7, 8)d → 7p, n(n = 5, 6)f → 6d, n(n = 5, 6)f → 6p². The population level distribution and the corresponding temperatures were obtained using Boltzmann plots. The plasma electron densities were determined using well-known Stark broadening parameters of spectral lines. Special attention was dedicated to the possible self-absorption of the different transitions. Temporal evolution of the plasma parameters was studied between 0.1 and 9 μs. Stark broadening parameters of the spectral lines were measured at 2.5 μs where the electron temperature was close to 11,300 K and the electron density to 0.8 × 10¹⁶ cm^− 3. The experimental results obtained have been compared with the experimental and theoretical values given by other authors. A systematic trend of this parameter versus temperature of 4244.9 Å Pb II line has been presented.     

Characterization,selenylation, and antineoplastic effects on HepG2 cells in vitro and in vivo of an arabinofuranan from the fruits of Akebia quinata

Akebia quinata is a traditional medicinal plant distributed in East Asia and its fruits are applicated in food and pharmaceutical fields. Herein, a novel polysaccharide (AQP70-2A) with a molecular weight of 1.49 × 10⁴ Da was isolated from the fruits of A. quinata. Results of the chemical and spectroscopic analysis indicated that AQP70-2A was an arabinofuranan with a backbone mainly consisting of → 5)-α-l-Araf-(1→, →3,5)-α-l-Araf-(1→, and → 2,3,5)-α-l-Araf-(1→, and it also contained two types of branch chains. At the cellular level, AQP70-2A did not show significant antitumor properties, while selenylation significantly made the inhibitory effect of this natural macromolecule on HepG2 cells to be increased. Furthermore, the zebrafish xenograft model confirmed that selenized polysaccharide Se-AQP70-2A effectively blocked hepatocellular carcinoma cells invasion and metastasis. Meanwhile, the inhibition of Se-AQP70-2A on development of intersegmental vessels revealed its antiangiogenic activity.     

Importance of covalence,conformational effects and tunneling-barrier heights for long-range electron transfer: Insights from dyads with oligo-p-phenylene,oligo-p-xylene and oligo-p-dimethoxybenzene bridges

This review reports on our recent studies of phototriggered charge transfer in rigid rod-like donor-bridge-acceptor molecules in liquid solution as well as between randomly dispersed electron donors and acceptors in frozen organic glasses. Investigation of the distance dependence of the rates of these reactions provides detailed insight into the various factors that govern long-range charge transfer efficiencies. The importance of covalence can be probed by a comparison of charge tunneling through a frozen toluene matrix to tunneling across an oligo-p-xylene bridge. The distance decay constants for these two processes are β = 1.26 Å^?1 and β = 0.52 Å^?1, respectively, indicating that charge tunneling across a covalent xylene–xylene contact is ～2 orders of magnitude more efficient than that across a noncovalent toluene–toluene contact. Conformational effects were investigated by comparing hole tunneling across oligo-p-xylene and oligo-p-phenylene bridges. The latter are significantly more π-conjugated and mediate long-range hole tunneling with β = 0.21 Å^?1 between a ruthenium–phenothiazine donor–acceptor couple. Quantitative analysis indicates that in this particular instance, tunneling across a phenylene–phenylene contact is roughly 50 times more efficient than tunneling across a xylene–xylene contact. The use of oligo-p-dimethoxybenzene wires instead of the structurally very similar oligo-p-xylene bridges was found to lead to a strong acceleration of long-range hole transfer rates: The 23.5-Å charge transfer step across four xylene units occurs within 20 μs, but the charge transfer over the same distance across four dimethoxybenzene units takes only 17 ns. This is attributed to a tunneling-barrier effect that is caused by a large difference in oxidation potentials between the two types of bridges.     

Dissociation of Multisubunit Protein–Ligand Complexes in the Gas Phase. Evidence for Ligand Migration

The results of collision-induced dissociation (CID) experiments performed on gaseous protonated and deprotonated ions of complexes of cholera toxin B subunit homopentamer (CTB₅) with the pentasaccharide (β-D-Galp-(1→3)-β-D-GalpNAc-(1→4)[α-D-Neu5Ac-(2→3)]-β-D-Galp-(1→4)-β-D-Glcp (GM1)) and corresponding glycosphingolipid (β-D-Galp-(1→3)-β-D-GalpNAc-(1→4)[α-D-Neu5Ac-(2→3)]-β-D-Galp-(1→4)-β-D-Glcp-Cer (GM1-Cer)) ligands, and the homotetramer streptavidin (S₄) with biotin (B) and 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-(biotinyl) (Btl), are reported. The protonated (CTB₅ + 5GM1)ⁿ⁺ ions dissociated predominantly by the loss of a single subunit, with the concomitant migration of ligand to another subunit. The simultaneous loss of ligand and subunit was observed as a minor pathway. In contrast, the deprotonated (CTB₅ + 5GM1)^n- ions dissociated preferentially by the loss of deprotonated ligand; the loss of ligand-bound and ligand-free subunit were minor pathways. The presence of ceramide (Cer) promoted ligand migration and the loss of subunit. The main dissociation pathway for the protonated and deprotonated (S₄ + 4B)^n+/– ions, as well as for deprotonated (S₄ + 4Btl)^n– ions, was loss of the ligand. However, subunit loss from the (S₄ + 4B)ⁿ⁺ ions was observed as a minor pathway. The (S₄ + 4Btl)ⁿ⁺ ions dissociated predominantly by the loss of free and ligand-bound subunit. The charge state of the complex and the collision energy were found to have little effect on the relative contribution of the different dissociation channels. Thermally-driven ligand migration between subunits was captured in the results of molecular dynamics simulations performed on protonated (CTB₅ + 5GM1)¹⁵⁺ ions (with a range of charge configurations) at 800 K. Notably, the migration pathway was found to be highly dependent on the charge configuration of the ion. The main conclusion of this study is that the dissociation pathways of multisubunit protein–ligand complexes in the gas phase depend, not only on the native topology of the complex, but also on structural changes that occur upon collisional activation.

Investigation by NMR Spectroscopy and Molecular Modeling of the Conformations of Some Modified Disaccharide Antigens for Shigella Dysenteriae Type 1

Abstract

The O-polysaccharide of Shigella dysenteriae type 1 is made up of multiple repeats of the linear tetrasaccharide 3)-α-L-Rhap-(1→2)-α-D-Galp-(1→3)-α-D-GlcpNAc-(1→3)-α-L-Rhap-(1→, for which the antigenic determinant for a murine monoclonal IgM antibody is the disaccharide α-L-Rhap-(1→2)-α-D-Galp. This disaccharide and various analogs have been studied by 2D NOESY, ROESY, and TOCSY NMR spectroscopy, in conjunction with proton spin-lattice relaxation rate measurements, restrained molecular mechanics, and restrained molecular dynamics with simulated annealing. It has been found that replacement of any single hydroxyl group in the determinant by a hydrogen atom, or replacement of any single hydroxyl group in the Gal residue by a fluorine atom has little if any influence on the conformation of the resulting derivatives.

     

1H NMR Studies of Hydroxy Protons of ASN- and Ser-Linked Disaccharides in Aqueous Solution

ABSTRACT

The hydroxy protons of β-D-GlcpNAc-(1→4)-β-D-GlcpNAc, β-D-GlcpNAc-(1→4)-β-D-GlcpNAc-N-Asn, β-D-Galp-(1→3)-α-D-GalpNAc-O-Me and of β-D-Galp-(1→3)-α-D-GalpNAc-O-Ser in aqueous solution have been investigated using ¹H NMR spectroscopy. The chemical shifts, coupling constants, temperature coefficients, exchange rates and NOEs have been measured. The O(3)H proton of β-D-GlcpNAc-(1→4)-β-D-GlcpNAc and β-D-GlcpNAc-(1→4)-β-D-GlcpNAc-N-Asn, and the O(2')H proton of β-D-Galp-(1→3)-α-D-GalpNAc and β-D-Galp-(1→3)-α-D-GalpNAc-O-Ser have values which differ significantly from the other hydroxy protons. Both these hydroxy protons are shielded when compared to those of the corresponding monosaccharide methyl glycosides. This shielding is attributed to the proximity of these protons to the O(5') oxygen and to the 2-acetamido group, respectively. In β-D-GlcpNAc-(1→4)-β-D-GlcpNAc and β-D-GlcpNAc-(1→4)-β-D-GlcpNAc-N-Asn, the O(3)H proton has restricted conformational freedom with a preferred orientation towards the O(5') oxygen, and is protected from exchange with the bulk water through a weak hydrogen bond interaction with O(5'). In β-D-Galp-(1→3)-α-D-GalpNAc-O-Me and β-D-Galp-(1→3)-α-D-GalpNAc-O-Ser, the O(2')H is protected from exchange with the bulk water by the 2-acetamido group. The conformations of the disaccharides are not affected by the amino acid, and no interaction in terms of hydrogen bonding between the sugars and the amino acid residue could be observed.     

Thermodynamics of proton dissociations from aqueous l-methionine at temperatures from (278.15 to 393.15) K,molalities from (0.0125 to 1.0) mol · kg−1, and at the pressure 0.35 MPa: Apparent molar heat capacities and apparent molar volumes of l-methionine,methioninium chloride,and sodium methioninate

We have measured the densities of aqueous solutions of l-methionine, l-methionine plus equimolal HCl, and l-methionine plus equimolal NaOH at temperatures 278.15 ⩽ T/K ⩽ 368.15, at molalities 0.0125 ⩽ m/mol · kg⁻¹ ⩽ 1.0 as solubilities allowed, and at p = 0.35 MPa using a vibrating tube densimeter. We have also measured the heat capacities of these solutions at 278.15 ⩽ T/K ⩽ 393.15 and at the same m and p using a twin fixed-cell differential temperature-scanning calorimeter. We used the densities to calculate apparent molar volumes V_ϕ and the heat capacities to calculate apparent molar heat capacities C_p,ϕ for these solutions. We used our results and values from the literature for V_ϕ(T, m) and C_p,ϕ(T, m) for HCl(aq), NaOH(aq), and NaCl(aq) and the molar heat capacity change Δ_rC_p,m(T, m) for ionization of water to calculate parameters for Δ_rC_p,m(T, m) for the two proton dissociations from protonated aqueous cationic l-methionine. We integrated these results in an iterative algorithm using Young’s Rule to account for the effects of speciation and chemical relaxation on V_ϕ(T, m) and C_p,ϕ(T, m). This procedure yielded parameters for V_ϕ(T, m) and C_p,ϕ(T, m) for methioninium chloride {H₂Met⁺Cl⁻(aq)} and for sodium methioninate {Na⁺Met⁻(aq)} which successfully modeled our observed results. Values are given for Δ_rC_p,m, Δ_rH_m, pQ_a, Δ_rS_m, and Δ_rV_m for the first and second proton dissociations from protonated aqueous l-methionine as functions of T and m.     

Magnetic property of 1:2 mixture of Co(p-tolsal)2; p-tolsal = N-p-tolylsalicylideniminato,and cyclic pentacarbene–pyridine with S = 10/2 in dilute frozen solution

A cyclic pentadiazo-pyridine ligand, cD5py, was prepared and its photoproduct, cC5py, in a frozen solution was confirmed to be a high-spin polycarbene with S = 10/2. The magnetic property of the 1:2 mixture of Co(p-tolsal)₂; p-tolsal = N-p-tolylsalicylideniminato, and cD5py in a dilute frozen solution after irradiation was investigated by SQUID magneto/susceptometry. In the ac magnetic susceptibility measurements, the in-phase and out-of-phase components (χ′ and χ″, respectively) with frequency dependence were observed, indicating that the 1:2 complex, Co(p-tolsal)₂-(cC5py)₂, had slow magnetic relaxation characteristic of the single-molecule magnet (SMM). From the χ″ versus T plots with various frequencies, the values of activation barrier, U_eff, for the reverse of the magnetism was estimated to be 72 K. In the dc magnetic susceptibility measurements, the magnetic hysteresis loops were observed below 3 K. The value of the coercive force, H_c, depends on the temperature and increases on cooling. The hysteresis loop with H_c = 7.1 kOe was observed at 1.9 K.     

Density and isothermal compressibility for two trialkylimidazolium-based ionic liquids at temperatures from (278 to 398) K and up to 120 MPa

In this paper, a densimeter based on vibrating tube principle is used to determine experimentally the density of 1-butyl-2,3-dimethylimidazolium tris(pentafluoroethyl)trifluorophosphate and 1-butyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide at temperatures between (278.15 and 398.15) K and at pressures up to 120 MPa. The apparatus was calibrated by using water, vacuum and bromobenzene. The Tammann–Tait equation of state was used to correlate (p, T, ρ) results with standard deviations around 2 · 10⁻⁴ g · cm⁻³. Other volumetric properties, such as isothermal compressibility and isobaric thermal expansivity, were obtained from this equation. For each ionic liquid, the α_p isotherms present a crossing point within the experimental pressure range. Besides, the effect that the C2-methylation in the imidazolium cation provokes on density values is analyzed. The prediction ability of the group contribution methods of Gardas and Coutinho and Jacquemin et al. were tested with the experimental densities.     

Critical behavior of binary mixture of {x C6H5CN + (1 − x) CH3(CH2)12CH3}: Measurements of coexistence curves,turbidity, and heat capacity

(Liquid + liquid) coexistence curve, turbidity, and isobaric heat capacity per unit volume for the critical solution of {benzonitrile + n-tetradecane} have been measured. The critical exponents β, ν, γ, and α and system-dependent critical amplitudes B, ξ₀, χ₀, and A^±, corresponding to the difference of the general density variable of two coexisting phases Δρ, the correlation length ξ, the osmotic compressibility χ, and the isobaric heat capacity per unit volume C_pV^?1, have been deduced and were used to test some universal ratios. The behavior of the diameter of the coexistence curves showed good agreement with the complete scaling theory. The analysis of effective critical exponent β_eff, which was well described by the crossover model proposed by Anisimov and Sengers, and effective critical exponent α_eff indicated monotonic crossover phenomena from 3D-Ising behavior to mean-field one as the temperature departed from the critical point.     

A new calcium trimellitate coordination polymer with a chain-like structure

The calcium trimellitate, Ca(H₂O)[(O₂C)₂–C₆H₃–CO₂H], was hydrothermally synthesized from a mixture of calcium hydroxide, 1,2,4-benzenetricarboxylic (or trimellitic) acid and water at 180 °C for 24 h (under autogenous pressure). Its crystal structure has been determined by single-crystal X-ray diffraction analysis using synchrotron radiation (station 9.8, SRS Daresbury, UK). It consists of infinite chains of calcium bicapped trigonal prismatic polyhedra connected to each other through the 1,2,4-benzenetricarboxylate ligand. The eight-fold coordinated calcium cation is bonded to one terminal water molecule, two carboxylate groups with a chelating conformation and three carboxylate groups in a monodentating mode. One of the monodentate carboxylate is terminal with the occurrence of protonated C–OH bonding.Triclinic space group P-1 with a = 6.9073(4) Å, b = 6.9917(4) Å, c = 10.3561(6) Å, α = 87.178(1)°, β = 83.233(1)°, γ = 69.576(1)°, V = 465.41(5) Å³.     

Electron excitation coefficients of neutral and ionic levels of krypton in Townsend discharges

In this paper, we present experimental results for excitation coefficients of krypton atoms to several Kr and Kr⁺ excited levels for E/N (electric field to gas particle number density ratio usually in units of Townsend, 1 Td = 10^− 21 V m²) values from 7 × 10^− 20 V m² to above 1 × 10^− 17 V m². The data have been obtained in two different parallel plate self-sustained Townsend discharge drift tubes. The spatial distribution of the emission intensities were recorded and then normalized to give excitation coefficients at the anode, by using the electron flux at this point. The values of these coefficients are placed on an absolute scale by using a standard tungsten ribbon lamp calibrated against a primary blackbody radiation standard. The ionization rates at different E/N are obtained from the spatial emission profiles.The data for atomic krypton levels 2p₂, 2p₃, 2p₅, 2p₆, 2p₇, 2p₈, 3p₅ and 3p₆ (in Paschen notation) were converted to excitation coefficients by using quenching coefficients from the literature. The emission coefficients of eight 4s²4p⁴ (³P)5p levels of Kr⁺ have also been measured for E/N values from about 1 × 10^− 18 V m² up to nearly 8 × 10^− 18 V m².