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Ling Jiang

Publications and source records attributed to Ling Jiang.

At least 19 recordsLinked to original sources
PubMed2006

Fine mapping of S32(t), a new gene causing hybrid embryo sac sterility in a Chinese landrace rice (Oryza sativa L.).

Ketan Nangka, the donor of wide compatibility genes, showed sterility when crossed to Tuanguzao, a landrace rice from Yunnan province, China. Genetic and cytological analyses revealed that the semi-sterility was primarily caused by partial abortion of the embryo sac. Genome-wide analysis of the linkage map constructed from the backcross population of Tuanguzao/Ketan Nangka//Ketan Nangka identified two independent loci responsible for the hybrid sterility located on chromosomes 2 and 5, which explained 18.6 and 20.1% of phenotypic variance, respectively. The gene on chromosome 5 mapped to the previously reported sterility gene S31(t), while the gene on chromosome 2, a new hybrid sterility gene, was tentatively designated as S32(t). The BC1F2 was developed for further confirmation and fine mapping of S32(t). The gene S32(t) was precisely mapped to the same region as that detected in the BC1F1 but its position was narrowed down to an interval of about 1.9 cM between markers RM236 and RM12475. By assaying the recombinant events in the BC1F2, S32(t) was further narrowed down to a 64 kb region on the same PAC clone. Sequence analysis of this fragment revealed seven predicted open reading frames, four of which encoded known proteins and three encoded putative proteins. Further analyses showed that wide-compatibility variety Dular had neutral alleles at loci S31(t) and S32(t) that can overcome the sterilities caused by these two genes. These results are useful for map-based cloning of S32(t) and for marker-assisted transferring of the neutral allele in hybrid rice breeding.

Base Pairing↗
PubMed2006

Reactions of gadolinium atoms and dimers with CO: formation of gadolinium carbonyls and photoconversion to CO activated molecules.

Reactions of gadolinium atoms and dimers with carbon monoxide molecules in solid argon have been studied using matrix isolation infrared absorption spectroscopy. Mononuclear Gd(CO)x (x = 1-3) and dinuclear Gd2(CO)x (x = 1, 2) gadolinium carbonyls formed spontaneously on annealing. The Gd(CO)x complexes are CO terminal-bonded carbonyls, whereas the Gd2CO and Gd2(CO)2 carbonyl complexes were characterized to have asymmetrically bridging and side-on-bonded CO, which are drastically activated with remarkably low C-O stretching frequencies. The cyclic Gd2(mu-C)(mu-O) and Gd3(mu-C)(mu-O) molecules in which the C-O triple bond is completely cleaved were also formed on annealing. The Gd2(CO)2 complex rearranged to the more stable c-Gd2(mu-O)(mu-CCO) isomer, which also has a four-membered ring structure with one CO being completely activated.

Journal Article↗
PubMed2006

Infrared spectra of the M(NO)n (M = Sn, Pb; n = 1, 2) and PbNO- molecules.

Reactions of laser-ablated tin and lead atoms with nitric oxide molecules in solid argon and neon have been investigated using matrix-isolation infrared spectroscopy. In the argon experiments, absorptions at 1560.1, 1625.8, and 1486.7 cm(-1) are assigned to the N-O stretching vibrations of the SnNO and Sn(NO)2 molecules, and absorptions at 1541.9, 1630.0, 1481.8, and 1457.5 cm(-1) are assigned to the N-O stretching vibrations of the PbNO, Pb(NO)2, and PbNO- molecules on the basis of isotopic shifts and splitting patterns. The present neon experiments only produce neutral tin and lead mononitrosyls. Density functional theory calculations have been performed on these tin and lead nitrosyls. The good agreement between the experimental and calculated vibrational frequencies, relative absorption intensities, and isotopic shifts substantiates the identification of these nitrosyls from the matrix infrared spectra.

Journal Article↗
PubMed2006

Infrared spectra of the (AgCO)2 and AgnCO (n=2-4) molecules in rare-gas matrices.

Reactions of laser-ablated silver atoms with carbon monoxide molecules in solid argon and neon have been investigated using matrix-isolation IR spectroscopy. Small silver cluster carbonyls, (AgCO)2 and AgnCO (n=2-4), as well as mononuclear silver carbonyls, Ag(CO)2 and Ag(CO)3, are generated upon sample annealing in the argon experiments and are characterized on the basis of the isotopic substitution, the CO concentration change, and the comparison with theoretical predictions. However, these polynuclear carbonyls are absent from the neon experiments. Density functional theory calculations have been performed on these silver carbonyls and the corresponding ligand-free silver clusters, which support the identification of these silver carbonyls from the matrix IRspectrum. A terminal CO has been found in the most stable structures of (AgCO)2, Ag2CO, Ag3CO, and Ag4CO. Furthermore, a plausible reaction mechanism has been proposed to account for the formation of the (AgCO)2 and AgnCO (n=2-4) molecules.

Journal Article↗
PubMed2006

Reactions of laser-ablated zinc and cadmium atoms with CO: infrared spectra of the Zn(CO)x (x = 1-3), CdCO-, and Cd(CO)2 molecules in solid neon.

Reactions of laser-ablated zinc and cadmium atoms with carbon monoxide molecules in solid neon have been investigated using matrix-isolation infrared spectroscopy. Based on the isotopic substitution, absorptions at 1852.2, 1901.9, 1945.9, and 1995.2 cm(-1) are assigned to the C-O stretching vibrations of the ZnCO, Zn(CO)(2), and Zn(CO)(3) molecules. Absorptions at 1735.8, 1961.3, and 2035.7 cm(-1) are assigned to the C-O stretching vibrations of the CdCO(-) and Cd(CO)(2) molecules. In contrast with the previous argon experiments, more species and more valuable information about the reaction of zinc and cadmium atoms with CO have been obtained in solid neon. Density functional theory calculations have been performed on these zinc and cadmium carbonyls. The agreement between the experimental and calculated vibrational frequencies, relative absorption intensities, and isotopic shifts substantiates the identification of these carbonyls from the matrix infrared spectrum. The present experiments also reveal that zinc is more reactive with CO than cadmium.

Journal Article↗
PubMed2006

Infrared spectroscopic and density functional theory studies on the CO dissociation by scandium and yttrium dimers.

Reactions of laser-ablated scandium and yttrium atoms with dilute carbon monoxide molecules in solid argon have been investigated using matrix-isolation infrared spectroscopy. On the basis of the results of the isotopic substitution, the change of laser power and CO concentration and the comparison with density functional theory (DFT) calculations, the absorption at 1193.4 cm(-1) is assigned to the C-O stretching vibration of the Sc(2)[eta(2)(mu(2)-C,O)] molecule, which has a single bridging CO that is tilted to the side. This CO-activated molecule undergoes ultraviolet-visible photoinduced rearrangement to the CO-dissociated molecule, c-Sc(2)(mu-C)(mu-O). The cyclic c-Sc(2)(mu-C)(mu-O) molecule has a bridging carbon on one side of the Sc(2) unit and a bridging oxygen on the other. The analogous Y(2)[eta(2)(mu(2)-C,O)] molecule has not been observed, but the CO-dissociated c-Y(2)(mu-C)(muO) molecule has been observed in the Y + CO experiments. DFT calculations of the geometry structures, vibrational frequencies, and IR intensities strongly support the assignments. The CO activation mechanism has also been discussed. Our experimental and theoretical results schematically depict an activation process to CO dissociation.

Argon↗
PubMed2006

A 'just-in-time' HN(CA)CO experiment for the backbone assignment of large proteins with high sensitivity.

Among the suite of commonly used backbone experiments, HNCACO presents an unresolved sensitivity limitation due to fast 13CO transverse relaxation and passive 13Calpha-13Cbeta coupling. Here, we present a high-sensitivity 'just-in-time' (JIT) HN(CA)CO pulse sequence that uniformly refocuses 13Calpha-13Cbeta coupling while collecting 13CO shifts in real time. Sensitivity comparisons of the 3-D JIT HN(CA)CO, a CT-HMQC-based control, and a HSQC-based control with selective 13Calpha inversion pulses were performed using a 2H/13C/15N labeled sample of the 29 kDa HCA II protein at 15 degrees C. The JIT experiment shows a 42% signal enhancement over the CT-HMQC-based experiment. Compared to the HSQC-based experiment, the JIT experiment is 16% less sensitive for residues experiencing proper 13Calpha refocusing and13Calpha-13Cbeta decoupling. However, for the remaining residues, the JIT spectrum shows a 106% average sensitivity gain over the HSQC-based experiment. The high-sensitivity JIT HNCACO experiment should be particularly beneficial for studies of large proteins to provide 13CO resonance information regardless of residue type.

Carbon Isotopes↗
PubMed2006

Infrared-spectroscopic and density-functional-theory investigations of the LaCO, La2[eta2(mu2-C,O)], and c-La2(mu-C)(mu-O) molecules in solid argon.

Reactions of laser-ablated lanthanum atoms with CO molecules in solid argon have been studied. The neutral lanthanum monocarbonyl (LaCO), produced upon sample deposition at 7 K, exhibits a C-O stretching frequency of 1772.7 cm(-1); to the best of our knowledge this is the lowest yet observed for a terminal CO in a neutral metal-carbonyl molecule (MCO, M = metal atom), implying anomalously enhanced metal-to-CO back-bonding. The infrared (IR) absorption band at 1145.9 cm(-1) is assigned to the C-O stretching mode of the side-on-bonding CO in the La2[eta2(mu2-C,O)] molecule. This CO-activated molecule undergoes an UV/Vis-photoinduced rearrangement to the CO-dissociated molecule, c-La2(mu-C)(mu-O). Density functional theory (DFT) calculations have been performed on these molecules, the results of which lend strong support to the experimental assignments of the IR spectra. LaCO is predicted to have a quartet ground state, corresponding to a linear geometry. Its formation involves La 6s-->4f promotion, which increases the strength of La-CO bonding by decreasing the sigma repulsion and, remarkably, by increasing the La 5d and 4f-->CO 2pi back-bonding. The observations schematically depict the whole process, starting with the interaction of CO with metal and ending with CO dissociation by the lanthanum dimer.

Journal Article↗
PubMed2006

Oxidation of carbon monoxide on group 11 metal atoms: matrix-isolation infrared spectroscopic and density functional theory study.

Laser-ablated Cu, Ag, and Au atoms react with CO and O2 mixture in solid argon to produce carbonyl metal oxides, (O2)Cu(CO)(n) (n = 1, 2), (eta(1)-OO)MCO (M = Ag, Au), OCAuO2CO, and OAuCO, as well as group 11 metal carbonyls and oxides. These carbonyl metal oxides are characterized using infrared spectroscopy on the basis of the results of the isotopic substitution and the CO concentration change. Density functional theory (DFT) calculations have been performed on these molecules. The identifications of these carbonyl metal oxides are confirmed by the good agreement between the experimental and calculated vibrational frequencies, relative absorption intensities, and isotopic shifts. Carbon dioxide is eliminated from these carbonyl metal oxides upon UV irradiation, providing the evidence for the oxidation of carbon monoxide on group 11 metal atoms. The present experiments also reveal that the reactivity of copper toward CO is prior to O2, and the reactivity of silver toward O2 is prior to CO, whereas the reactivity of gold toward CO is comparable to O2.

Journal Article↗
PubMed2005

Infrared spectroscopic and density functional theory studies on the reactions of cadmium atoms with carbon monoxide in solid argon.

Reactions of laser-ablated cadmium atoms with carbon monoxide molecules in solid argon have been investigated using matrix isolation infrared spectroscopy. On the basis of isotopic substitution, the absorption at 1858.2 cm(-1) is assigned to the C-O stretching of the CdCO molecule, which is formed during the sample deposition. Cadmium di- and tricarbonyls, Cd(CO)n (n = 2, 3), have not been observed under the same experimental conditions. Density functional theory calculations have been performed on the cadmium carbonyls Cd(CO)n (n = 1-3), which lend strong support to the experimental assignments of the infrared spectra. It is predicted that the CdCO molecule is a linear triplet molecule and its formation involves Cd 5s --> 5p promotion. This promotion increases the Cd-CO bonding by decreasing the sigma repulsion and increasing the Cd 5p orbital --> CO pi back-donation. The absence of cadmium di- and tricarbonyls, Cd(CO)n (n = 2, 3), has also been discussed in some detail.

Journal Article↗
PubMed2005

Cluster and periodic DFT calculations: the adsorption of atomic nitrogen on M(111) (M = Cu, Ag, Au) surfaces.

First-principle density functional calculations with cluster and slab models have been performed to investigate adsorption and thermally activated atomic nitrogen on M(111) (M = Cu, Ag, Au) surfaces. Optimized results indicate that the basis set of the N atom has a distinct effect on the adsorption energy but an indistinct one on the equilibrium distance. For the N/M(111) adsorption systems studied here, the threefold face centered cubic (fcc) hollow site is found to be the most stable adsorption site. The reason for the fcc site is that the perfected adsorption site has been explained by the density of states (DOS) analysis, that is, that N(2p) has the smallest DOS population near the Fermi level on the fcc site as compared with other adsorption sites. The variations of the adsorption energy as a function of adsorption site are similar and in the following order of N-M(111) binding strengths on a given site: Cu(111) > Ag(111) > Au(111). It is found that the N atom forms essentially an ionic bond for the most stable site. Large contributions between the M(ns) and N(2p) orbitals (n = 4, 5, and 6 for Cu, Ag, and Au, respectively) are found for the cluster model at the B3LYP/LANL2DZ-6-31G(d,p) level and also found in the slab DFT-GGA calculation results, which are the main characteristics of M-N bonds. At last, the dissociation of N2 on Cu(111) and Au(111) has also been obtained in this work, and the results showed that the dissociation of N2 on Cu(111) is more active than that on the Au(111) surface.

Journal Article↗
PubMed2005

Experimental and theoretical evidence for the formation of zinc tricarbonyl in solid argon.

Zinc carbonyls are extremely rare. Here we report experimental and theoretical evidence of unprecedented zinc tricarbonyl, Zn(CO)3, the next member of the series of 18-electron metal carbonyls Cr(CO)6 --> Fe(CO)5 --> Ni(CO)4, whereas there is no evidence for the formation of the zinc mono- and dicarbonyls Zn(CO)n (n = 1, 2). DFT calculations predict that the Zn(CO)3 molecule has a singlet ground state with D3h symmetry. The formation of Zn(CO)3 involves 4s --> 4p promotion of the Zn atom, which increases the Zn-CO bonding by decreasing the sigma repulsion and significantly increasing the Zn 4sp hybrid orbitals --> CO pi* back-donation.

Argon↗
PubMed2005

[The investigation of genotype and expression of alpha1-AT in patients with COPD].

OBJECTIVE: To detect genotype and expression of alpha1-AT in the patients with COPD to investigate the effect of alpha1-AT on pathogenesis of COPD. METHODS: Detection of PiZ allele in exon V and S allele in exon III were performed by PCR-Amplification of Specific Allele (PASA). The levels of serum alpha1-AT in some of subjects were measured by Enzyme-Linked Immunoadsordent Assay (ELISA). RESULTS: The PCR production of S mutation was 285 base pair fragment. The PCR production of Z-mutation was 250 base pair fragment. The results showed that All subjects were PiMM genotype of alpha1-AT, including COPD and control group. The mean serum alpha1-AT concentration, in patients with COPD, was 2.3 g/L +/- 1.1 g/L. In control group, the mean serum alpha1-AT concentration was 2.7 g/L +/- 0.84 g/L. The levels of alpha1-AT in patients with COPD are significantly lower than that in control group (P = 0.012). RV/TL and degree of pursiness are negative correlation with the levels of alpha1-AT. The r value were -0.208 and -0.262 respectively. CONCLUSION: There was no difference in genetic polymorphism of alpha1-AT between the patients with COPD and controls. However, the levels of serum alpha1-AT were significantly lower in the patients with COPD compared with control subjects. alpha1-AT deficiency may be a factor of the pathogenesis of COPD. The mechanism of alpha1-AT deficiency needs to be addressed.

Aged↗
PubMed2005

Reactions of germanium atoms and small clusters with CO: experimental and theoretical characterization of Ge(n)CO (n = 1-5) and Ge2(CO)2 in solid argon.

Reactions of germanium atoms and small clusters with carbon monoxide molecules in solid argon have been studied using matrix isolation infrared absorption spectroscopy. Besides the previously reported GeCO monocarbonyl, the Ge2(CO)2 and Ge(n)CO (n = 2-5) carbonyl molecules are formed spontaneously on annealing and are characterized on the basis of isotopic substitution and theoretical calculations. It is found that Ge2CO, Ge3CO, and Ge5CO are bridge-bonded carbonyl compounds, whereas Ge2(CO)2 and Ge4CO are terminal-bonded carbonyl molecules.

Journal Article↗
PubMed2005

Association of gene polymorphisms of tumour necrosis factor-alpha and interleukin-13 with chronic obstructive pulmonary disease in Han nationality in Beijing.

BACKGROUND: Genetic factors are believed to play a role in the individual susceptibility to chronic obstructive pulmonary disease (COPD). A single nucleotide polymorphism (SNP) of tumour necrosis factor-alpha (TNF-alpha) has been reported but inconsistent results may arise from different populations and phenotypes of COPD. There are only a few published studies of interleukin-13 (IL-13) SNPs on COPD. The SNPs of TNF-alpha and IL-13 have not been studied in the Chinese population. This research was conducted to study the frequencies of IL-13 gene promoter 1055 (IL-13-1055) and TNF-alpha gene-308 polymorphisms in the patients with COPD and to investigate the effect of those genetic polymorphisms on COPD in the Chinese population. METHODS: A cohort of COPD patients and age matched controls were recruited from an inpatient hospital service in Beijing. Venous blood was obtained and genomic DNA was extracted from peripheral blood monocytes using standard method. Genomic DNA was used as a template for amplification by polymerase chain reaction (PCR) to determine the polymorphism at -1055 in the IL-13 gene promoter region. PCR restriction fragment length polymorphism (RFLP) was used to determine polymorphisms in the TNF-alpha gene-308 position. The products were investigated by sequence analysis also. RESULTS: One hundred and eleven COPD patients and 97 controls were studied. Seventy-five cases were current smokers in COPD patients and 36 were current smokers in controls. The frequencies of TT genotype in the IL-13 gene promoter region were 11.7% (13/111) in the COPD group and 13.4% (13/97) in the controls (P = 0.713). However, the OR value of TT genotype was significantly increased to 6.4 (95% CI 1.62 - 25.39) in the smokers with COPD. TT genotype was also positively related to family history of COPD, OR = 7.7 (95% CI 1.37 - 43.80). The frequencies of A allele in the TNF-alpha gene were 5.9% in COPD and 3.1% in controls (P = 0.131). The OR value of A allele was 5.0 (95% CI 1.011 to 25.059) in smokers with COPD. CONCLUSIONS: There is no significant difference in the frequencies of the TT genotype of IL-13-1055 or the A allele of the TNF-alpha between Han Chinese patients with COPD versus control. Thus, it does not appear that these SNPs are independent factors in COPD for Han nationality in Beijing. However, these SNPs may increase the risk of COPD among smokers.

Adult↗
PubMed2005

Reactions of gold atoms and small clusters with CO: Infrared spectroscopic and theoretical characterization of Au(n)CO (n = 1-5) and Au(n)(CO)2 (n = 1, 2) in solid argon.

Laser-ablated Au atoms have been co-deposited with CO molecules in solid argon to produce gold carbonyls. In addition to the previously reported Au(CO)n (n = 1, 2) and Au2(CO)2 molecules, small gold cluster monocarbonyls Au(n)CO (n = 2-5) are formed on sample annealing and characterized using infrared spectroscopy on the basis of the results of the isotopic substitution and CO concentration change and comparison with theoretical predictions. Of particular interest is that the mononuclear gold carbonyls, Au(CO)n (n = 1, 2), are favored under the experimental conditions of higher CO concentration and lower laser energy, whereas the yields of the gold cluster carbonyls, Au(n)CO (n = 2-5) and Au2(CO)2, remarkably increase with lower CO concentration and higher laser power. Density functional theory (DFT) calculations have been performed on these molecules and the corresponding small naked gold clusters. The identities of these gold carbonyls Au(n)CO (n = 1-5) and Au(n)(CO)2 (n = 1, 2) are confirmed by the good agreement between the experimental and calculated vibrational frequencies, relative absorption intensities, and isotopic shifts.

Journal Article↗