805 research outputs found
ELECTRONIC SPECTRA OF THE THREE, FOUR, AND FIVE ELECTRON ELECTRON (AND HOLE) TRANSITION METAL CYANIDES AND OF THE TETRAGONAL PLATINUM (II) COMPOUNDS. PART II.
No full text J. R. Perumareddi and A. D. Liehr, Symposium on Molecular Structure and Spectroscopy, The Ohio State University, Columbus, Ohio, June 15-19, 1964 (Part I). A. D. Liehr, J. Phys. Chem. 67, 1314 (1963). A. D. Liehr, Symposium on Molecular Structure and Spectroscopy, The Ohio State University, Columbus, Ohio, June 15-19, 1964. A. D. Liehr, Symposium on the Structure and Properties of Coordination Compounds, Bratislava. Czechoslovakia, September 2-4, 1964. J. R. Perumareddi and A. D. Liehr, Symposium on Molecular Structure and Spectroscopy, The Ohio State University, Columbus, Ohio, June 14-18, 1965.Author Institution: Mellon Institute, 4400 Fifth AvenueFurther studies have bee made on the measurement and interpretation of the electronic spectra of the cyanides and the tetragonal platinum (II) compounds reported particularly in the infrared region and at low temperatures. Assignments of some of the bands in these systems have been rationalized using the energy levels and the eigen vectors obtained by solving the complete set of energy matrices for the corresponding and the results have been graphically and tabularly portrayed. Conclusions are drawn and words of causation and prudence are uttered
THE TWO ELECTRON (OR HOLE) CUBIC AND NON-CUBIC LIGAND FIELD SPECTRUM.
No full text A. D. Liehr, J. Phys. Chem. 64, 43 (1960). A. D. Liehr and C. J. Ballhausen, Ann. Phys. (N.Y.) 6, 134 (1959). A. D. Liehr, J. Phys. Chem. 67, 1314 (1963). A. D. Liehr, Symposium on Molecular Structure and Spectroscopy, The Ohio State University, Columbus, Ohio, June 15-19, 1964. A. D. Liehr, Symposium on the Structure and Properties of Coordination Compounds, Bratislava, Czechoslovakia, September 2-4, 1964. A. D. Liehr, Symposium on Molecular Structure and spectroscopy, The Ohio State University, Columbus, Ohio, June 14-18, 1965.Author Institution: Mellon Institute, 4400 Fifth AvenueThe most general set of secular equations for a , transition metal complex in cubic, quadrate, trigonal, and cylindrical fields which are allowed by the fundamental approximations of ligand field theory have been derived in a wide variety of representations and bases. Proceeding as in the previous investigations of the , problems in cubic environs we have computed the variation of the energy as a function of the spin-orbit constant , the electron correlation integrals B and C, and the ligand field parameters Dq (cubic), Dq, Ds, and Dt (quadrate), Dq, , and (trigonal), and and (cylindrical). Employing a fixed ratio for C/B (usually at the University of Pittsburgh. The results obtained have been plotted and will be presented in graphical forms. The usefulness of these energy diagrams for the interpretation of the spectroscopic properties of compounds of two electron (and hole) configuration in quadrate, trigonal, and cylindrical fields will be underscored and a discourse on the appropriateness and practicality of the different theoretical bases and representations employed will be given
The acrocentric part of der(Y)t(Y;acro)(q12;p1?2) contains D15Z1 sequences in the majority of cases
No full textInfertility: The origin of a Y-chromosome abnormality Researchers in Germany have clarified the origin of an abnormality in the Y-chromosome linked with infertility. Some chromosome regions are susceptible to variation, such as translocation with segments of other chromosomes. A team of researchers led by Thomas Liehr of the Jena University Hospital, investigated a Y-chromosome abnormality in seven men. Visual analysis of the chromosomes of all seven showed an aberration at the tip of the long arm of the chromosome, probably derived from an exchange with another chromosome. The researchers then used fluorescent probes to characterize the Y-chromosome. A general probe that binds the short arm of any acrocentric chromosome (chrs. 13, 14, 15, 21, 22) generated a signal. Further testing with probes for specific chromosomes revealed that the aberrant region is derived predominantly from the short arm of chromosome 15
Andrew Liehr and the structure of Jahn-Teller surfaces
No full text© Published under licence by IOP Publishing Ltd. The present article is an attempt to draw attention to a seminal work by Andrew Liehr "Topological aspects of conformational stability problem" [1, 2] issued more than half century ago. The importance of this work stems from two aspects of static Jahn-Teller and pseudo-Jahn-Teller problems fully developed by the author. First, the work of Liehr offers an almost complete overview of adiabatic potential energy surfaces for most known Jahn-Teller problems including linear, quadratic and higher-order vibronic couplings. Second, and most importantly, it identifies the factors defining the structure of Jahn-Teller surfaces. Among them, one should specially mention the minimax principle stating that the distorted Jahn-Teller systems tend to preserve the highest symmetry consistent with the loss of their orbital degeneracy. We believe that the present short reminiscence not only will introduce a key Jahn-Teller scientist to the young members of the community but also will serve as a vivid example of how a complete understanding of a complex problem, which the Jahn-Teller effect certainly was in the beginning of 1960s, can be achieved.sponsorship: We would like to thank Isaac Bersuker, Victor Polinger and Janette Dunn for useful discussions. N. I. is a postdoctoral researcher under Japan Society for the Promotion of Science (JSPS) Postdoctoral Research Fellowships for Research Abroad and also gratefully acknowledges financial support from GOA grant from the KU Leuven. (Japan Society for the Promotion of Science (JSPS) Postdoctoral Research Fellowships for Research Abroad, GOA from the KU Leuven)status: Publishe
Rhinolophus lanosus Volleth, Son, Wu, Li, Yu, Lin, Arai, Trifonov, Liehr & Harada, 2017, stat. rev.
No full textRhinolophus lanosus stat. rev. The female from Sichuan province, China, showed a diploid chromosome number of 2 n = 32 and a FNa = 60. The karyotype was composed of 15 meta- to submetacentric autosomal pairs and two metacentric X chromosomes (Fig. 4). Heterochromatin was detected by C-banding at all centromeres and in the proximal part of the short arm of the X chromosome. The size of this heterochromatic segment differed between both homologs of the female studied (inset of Fig. 4). The NORs are located at the secondary constriction in the short arm of pair 8. This chromosomal arm is homologous to MMY21. The frequency of active NORs as detected by silver-staining was 1.8 NORs per cell (10 metaphase spreads analyzed). The composition of autosomal arms was studied by combination of whole chromosome painting probes from A. stoliczkanus, complemented by some M. myotis probes (MMY8, 14, 18). The hybridization results are summarized on the karyotype (Fig. 4), and as examples metaphase spreads hybridized with probes from AST 1, 2 and 8 are shown (Fig. 3B and 3E). G-banding and FISH results revealed that the karyotype of R. lanosus differs from that of R. luctoides and R. cf. luctoides from Vietnam by a whole arm reciprocal translocation (WART) between pairs 3 and 4. In the karyotype of R. cf. luctoides, pair 3 is composed of arms homologous to AST2 ad AST5, whereas in R. lanosus it consists of arms homologous to AST7 and AST5. Homology to AST1 and AST7 is found in pair 4 of R. cf. luctoides, but to AST1 and AST 2 in R. lanosus (Fig. 5).Published as part of Volleth, Marianne, Son, Nguyen Truong, Wu, Yi, Li, Yuchun, Yu, Wenhua, Lin, Liang-Kong, Arai, Satoru, Trifonov, Vladimir, Liehr, Thomas & Harada, Masashi, 2017, Comparative chromosomal studies in Rhinolophus formosae and R. luctus from China and Vietnam: elevation of R. l. lanosus to species rank, pp. 41-50 in Acta Chiropterologica 19 (1) on page 44, DOI: 10.3161/15081109ACC2017.19.1.003, http://zenodo.org/record/394481
THE THREE ELECTRON (OR HOLE) CUBIC LIGAND FIELD SPECTRUM
No full textJ. C. Eisenstein, (private communication, 1960) and J. Chem. Phys. (in press); \emph{ibid}. 32, 1887 (1960); \emph{ibid}. 33, 1530 (1960). H. A. Weakliem, Jr., (private communication, 1960). G. Racah, Schonfeld, Miss G., and Low. W.. (private communication, 1960), and Miss G. Schonfeld, thesis, Hebrew University, Israel, 1959. A. D. Liehr and Ballhausen, C. J., Ann. Phys. [N.Y.] 6, 134, (1959). A. D. Liehr, J. Phys. Chem. 64, 43 (1960).Author Institution: Bell Telephone Laboratories IncorporatedThe most general set of secular equations for a , (k = 3, 4, 5), transition metal complex in a cubic environs which is allowed by the fundamental approximations of ligand field theory has recently been derived by Eisenstein and has been subsequently utilized by him to interpret the magnetic and optical properties, of and As his final energy determinants have a more lucid form than the presently available (corresponding) unpublished energy matrix elements of and of Recah, Schonfeld, and we have used those of Eisenstein in our present systematic study of the optical properties of the cubic transition metal systems. Proceeding as in our previous investigations of the , (n = l, 2, 8, 9), we have computed the variation of the energy as a function of the ligand field parameter Dq, the spin-orbit coupling constant , and the electron correlation integrals B and C. To simplify our problem and to save time on the Bell Telephone Laboratories I.B.M. 7090 data processing machine, we have employed the theoretical ratio of C/B of 4 in our calculations. The results obtained have been graphically and tabularly portrayed and will be presented in these forms. Particular attention will be paid to the spectral effects of spin-orbit interactions in a variety of , (k = 3, 4, 5) compounds, and a general commentary on the future usefulness of this and other will be given
8p23.1 duplication syndrome differentiated from copy number variation of the defensin cluster at prenatal diagnosis in four new families
No full textBackground: the 8p23.1 duplication syndrome and copy number variation of the 8p23.1 defensin gene cluster are cytogenetically indistinguishable but distinct at the molecular level. To our knowledge, the 8p23.1 duplication syndrome has been described at prenatal diagnosis only once and we report our experience with four further apparent duplications ascertained at prenatal diagnosis.Methods: additional material at band 8p23.1 was detected using conventional G-banded cytogenetics in each case. Multiplex Ligation-dependent Probe Amplification (MLPA) or Fluorescence In Situ Hybridisation (FISH) were used depending on whether only DNA (Cases 1 and 4) or cytogenetic preparations (Cases 2 and 3) were available from the laboratory of origin. The extent of the duplication in Case 1 was retrospectively determined using array Comparative Genomic Hybridisation (array CGH).Results: three cases of 8p23.1 duplication syndrome were found (Cases 1 to 3). Two were de novo and continued to term and the third, a paternally transmitted duplication, was terminated because of a previous child with psychomotor delay and 8p23.1 duplication syndrome. Case 1 was ascertained with a hypoplastic left heart but the ventricular septal and interventricular defects, in Cases 2 and 3 respectively, were found after ascertainment for advanced maternal age. By contrast, case 4 was a maternally transmitted copy number variation of the defensin cluster with normal outcome.Conclusions: our data underline the need to differentiate 8p23.1 duplications from copy number variation of the defensin cluster using FISH, MLPA or array CGH. Cardiac defects were ascertained by ultrasound in only one of the three duplication 8p23.1 pregnancies but were visible in two of the three at 21 to 22 weeks gestation. Our results provide further evidence that both deletion and duplication of the GATA4 transcription factor can give rise to a variety of conotruncal heart defects with variable penetrance and expressivit
Rapid detection of subtelomeric deletion/duplication by novel real-time quantitative PCR using SYBR-green dye
No full textTelomeric chromosome rearrangements may cause mental retardation, congenital anomalies, miscarriages, and hematological malignancies. Automated detection of subtle deletions and duplications involving telomeres is essential for high-throughput screening procedures, but impractical when conventional cytogenetic methods are used. Novel real-time PCR quantitative genotyping of subtelomeric amplicons using SYBR green dye allows high-resolution screening of single copy number gains and losses by their relative quantification against a diploid genome. To assess the applicability of the technique in the screening and diagnosis of subtelomeric imbalances, we describe here a blinded study in which DNA from 20 negative controls and 20 patients with known unbalanced cytogenetic abnormalities involving at least one or more telomeres were analyzed using a novel human subtelomere-specific primer set, producing altogether 86 amplicons, in the SYBR-green I-based real, time quantitative PCR screening approach. Screening of the DNA samples from 20 unrelated controls for copy number polymorphism do not detect any polymorphism in the set of amplicons, but single-copy-number gains and losses were accurately detected by quantitative PCR in all patients, except the copy number alterations of the subtelomeric p-arms of the acrocentric chromosomes in two cases. Furthermore, a detailed mapping of the deletion/translocation breakpoint was demonstrated in two cases by novel real,time PCR "primer-jumping." Because of the simplicity and flexibility of the SYBR-green I-based real,time detection, the primer-set can easily be extended, either to perform further detailed molecular characterization of breakpoints or to include amplicons for the detection and/or analysis of syndromes that are associated with genomic copy number alterations, e.g., detetion/duplication-syndromes and malignant cancers. (C) 2004 Wiley-Liss, Inc
Autistic disorder and chromosomal mosaicism 46,XY[123]/46,XY,del(20)(pter -> p12.2)[10]
No full textWe report on a 3-year-old boy with a moderate to severe mental retardation, autistic behavior patterns, and myoclonic epilepsy of early childhood. The cytogenetic analysis of blood lymphocytes revealed a deletion of chromosome 20pter --> p12.2 occurring as mosaicism in 8% of the analyzed metaphases:46,XY[123]/46,XY,del(20)(pter --> p12.2)[10]. The deletion was confirmed by the recently developed multicolor banding approach and additionally by region specific fluorescence in situ hybridization (FISH) probes. To the best of our knowledge, this is the first report on a patient with autistic behavior with terminal 20p deletion mosaicism reported up to present. (C) 2003 Wiley-Liss, Inc
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