Synthesis,characterization and thermoluminescence studies of (ZnS)1‐x(MnTe)x nanophosphors

The present paper reports the thermoluminescence (TL) of (ZnS)_1‐x(MnTe)_x nanophosphors that were prepared by a wet chemical synthesis method. The structure investigated by X‐ray diffraction patterns confirms the formation of a sphalerite phase whose space group was found to be F 3m. From XRD, TEM and SEM analyses the average sizes of the particles were found to be 12 nm, 11 nm and 15 nm, respectively. Initially the TL intensity increased with increasing values of x because the number of luminescence centres increased; however, for higher values of x the TL intensity decreased because of the concentration quenching. Thus the TL, mechanoluminescence and photoluminescence intensities are optimum for a particular value of x, that is for x = 0.05. Thermoluminescence of the (ZnS)_1‐x (MnTe)_x nanophosphor has not been reported previously. There were two peaks seen in the thermoluminescence glow curves in which the first peak lay at 105–100 °C and the second peak lay at 183.5–178.5 °C. The activation energies for the first and second peaks were found to be 0.45 eV and 0.75 eV, respectively.     

Biochemical characterization of lines descended from 8x triticale x 4x triticale cross

Summary Fifty-two progenies originating from a cross between 8x and 4x triticale were submitted to cytogenetic analyses and to various electrophoretic studies [high-molecular-weight (HMW) glutelins, HMW secalins, -secalins, and -gliadins, -amylases] to identify new genetic structures, more specifically the input of the D genome in a genetic context other than the wheat one. Markers of the rye genome (HMW and -secalins) were identified in all of the triticale lines, but they originated either from the 4x or from the 8x parent, or from both. Chromosomes 4A, 1B, and 2R, present in both parents, showed the same banding patterns in all progenies. Chromosomes 1R and 5R, present in both parents, showed heterogeneous labelling. The expression of chromosomes 6A, 1D, and 4D, present in the 8x parent only, was more complex with a possible involvement of a regulatory system. Several hexaploid progenies had introgressed part of the D genome, suggesting that crossing 8x and 4x triticale was a practicable approach for transferring D chromosomes into hexaploid triticale.     

Fragile x syndrome

Recent data from a national survey highlighted a significant difference in obesity rates in young fragile X males (31%) compared to age matched controls (18%). Fragile X syndrome (FXS) is the most common cause of intellectual disability in males and the most common single gene cause of autism. This X-linked disorder is caused by an expansion of a trinucleotide CGG repeat (>200) on the promotor region of the fragile X mental retardation 1 gene (FMR1). As a result, the promotor region often becomes methylated which leads to a deficiency or absence of the FMR1 protein (FMRP). Common characteristics of FXS include mild to severe cognitive impairments in males but less severe cognitive impairment in females. Physical features of FXS include an elongated face, prominent ears, and post-pubertal macroorchidism. Severe obesity in full mutation males is often associated with the Prader-Willi phenotype (PWP) which includes hyperphagia, lack of satiation after meals, and hypogonadism or delayed puberty; however, there is no deletion at 15q11-q13 nor uniparental maternal disomy. Herein, we discuss the molecular mechanisms leading to FXS and the Prader-Willi phenotype with an emphasis on mouse FMR1 knockout studies that have shown the reversal of weight increase through mGluR antagonists. Finally, we review the current medications used in treatment of FXS including the atypical antipsychotics that can lead to weight gain and the research regarding the use of targeted treatments in FXS that will hopefully have a significantly beneficial effect on cognition and behavior without weight gain.     

The biochemical basis of 5-bromouracil-induced mutagenesis. Heteroduplex base mispairs involving bromouracil in G x C----A x T and A x T----G x C mutational pathways

We have investigated the mechanism of bromouracil-induced transition mutations in vitro using synthetic DNA templates and purified T4 DNA polymerase. Evidence is presented for the occurrence of bromouracil-guanine base pairs in product DNA in the G x C----A x T pathway where guanine is present in the DNA template and bromouracil is present as the deoxynucleoside triphosphate substrate 5-bromodeoxyuridine triphosphate. This finding supports a widely known but as yet untested model proposed by Freese (Freese, E. (1959) J. Mol. Biol. 1, 87-105) in which bromouracil-guanine base pairs are intermediates in 5-bromodeoxyuridine-induced transition mutation pathways. We find that the newly formed B x G base pairs are proofread with an efficiency of 75-85% by the 3' -exonuclease of T4 polymerase. The insertion of bromouracil occurring in direct competition with cytosine deoxyribonucleotides opposite template guanine sites is 1.1 +/- 0.14% (mean +/- S.E.), and the misincorporation ratio, inc(B)/inc(C), is reduced 6-fold by the action of the proofreading exonuclease to 0.16 +/- 0.02% (mean +/- S.E.). A previous study by Trautner et al. (Trautner, T. A., Swartz, M. N., and Kornberg, A. (1962) Proc. Natl. Acad. Sci. U. S. A. 48, 449-455) suggested that, while template bromouracil stimulates incorporation of dGMP in the A x T----G x C transition mutation pathway, it may not be occurring exclusively by the pathway proposed by Freese. We concur with these earlier results, and, in addition, we find the surprising result that the 3'-exonuclease activity of wild-type T4 polymerase removes little or no incorporated dGMP on bromouracil-containing templates.     

Unassisted Water Splitting Using a GaSbxP(1−x) Photoanode

Here, unbiased water splitting with 2% solar‐to‐hydrogen efficiency under AM 1.5 G illumination using new materials based on GaSb_0.03P_0.97 alloy is reported. Freestanding GaSb_xP_1?x is grown using halide vapor phase epitaxy. The native conductivity type of the alloy is modified by silicon doping, resulting in an open‐circuit potential (OCP) of 750 mV, photocurrents of 7 mA cm^?2 at 10 sun illumination, and corrosion resistance in an aqueous acidic environment. Alloying GaP with Sb at 3 at% improves the absorption of high‐energy photons above 2.68 eV compared to pure GaP material. Electrochemical Impedance Spectroscopy and illuminated OCP measurements show that the conduction band of GaSb_xP_1?x is at ?0.55 V versus RHE irrespective of the Sb concentration, while photocurrent spectroscopy indicates that only radiation with photon energies greater than 2.68 eV generate mobile and extractable charges, thus suggesting that the higher‐laying conduction bands in the Γ 1 valley of the alloys are responsible for exciton generation.     

Creating new forms of 4x, 6x and 8x primary triticale associating both complete R and D genomes

Summary Strains of Aegilops squarrosa L. and Ae. ventricosa L. were pollinated either by Secale cereale L. or tetraploid triticale. Using in vitro culture of immature F1 embryos, the four corresponding hybrids were obtained. Successful doubling occurred following colchicine treatment, leading to the creation of new amphidiploid structures (C1 plants). These correspond to primary triticale forms involving, at three different levels of ploidy, both R and D full complements. The various combinations were compared for their response at successive steps of the process. Crosses involving Ae. squarrosa present a higher fruit setting than those with Ae. ventricosa, which in contrast yield colchicine treated-plants with better grain fertility. Experimental data on the cytological behaviour and fertility of colchicine-treated as well as amphidiploid plants are presented. The importance of this material in triticale breeding is discussed.     

Synthesis and characterization of Y(1‐x)Eu(x)(TTA)3(Phen) organic luminescent thin films

Yttrium is stoichiometrically doped into europium by mole percentage, during the synthesis of Y_(1‐x)Eu_(x)(TTA)₃(Phen), using solution techniques (where x = 0.2, 0.4, 0.5, 0.6 and 0.8, TTA = thenoyltrifluoroacetone and Phen = 1,10‐phenanthroline).These complexes were characterized using different techniques such as X‐ray diffraction, thermogravimetric/differential thermal analysis, optical absorption and emission spectra. Thin films of the doped Eu–Y complexes were prepared on a glass substrate under a high vacuum of 10^‐6 Torr. The photoluminescence spectra of these thin films were recorded by exciting the sample at a wavelength of 360 nm. The emission peak for all the synthesized complexes centered at 611 nm; maximum emission intensity was obtained from Y_0.6Eu_0.4 (TTA)₃(Phen). The results proved that these doped complexes are more economical than pure Eu(TTA)₃(Phen) and are best suited as red emissive material for energy‐efficient and eco‐friendly organic light‐emitting diodes and displays. Copyright © 2013 John Wiley & Sons, Ltd.     

A new approach for obtaining rapid uniformity in rice (Oryza sativa L.) via a 3x x 2x cross

A triploid (2n = 3x = 36) rice plant was obtained by screening a twin seedling population in which each seed germinated to two or three sprouts that were then crossed with diploid plants. One diploid plant was chosen among the various F(1) progenies and developed into an F (2) population via self-pollination. Compared with the control variety Shanyou 63, this F (2) population had a stable agronomical performance in field trials, as confirmed by the F-test. The stability of the F (2) population was further substantiated by molecular analysis with simple sequence repeat markers. Specifically, of 160 markers assayed, 37 (covering all 12 chromosomes) were polymorphic between the parental lines. Testing the F (1) hybrid individually with these markers showed that each PCR product had only a single band instead of two bands from each parent. The bands were identical to either maternal (23 markers) or paternal (eight markers) bands or distinct from both parents (six markers). The amplified bands of all 60 randomly selected F (2) plants were uniform and identical to those of the F (1) hybrid. These results suggest that the F (1) plant is a non-segregating hybrid and that a stable F (2) population was obtained. This novel system provides an efficient means for shortening the cycle of hybrid rice seed production.     

Fitness components of the hybrid Phlomis x margaritae Aparicio & Silvestre (Lamiaceae)

Studies of microsporogenesis, pollen germination, pollen stainability, fruit and seed set and ovary predation have been undertaken to evaluate the fitness of the hybrid genotype of Phlomis x margaritae relative to its parents (P. purpurea and P. x composita) and allied taxa (P. x composita nothom. composita, P. x composita nothom. trulknqueiz , and P. lychnitis). Phlomis x margaritae shows irregular meiosis with very low pollen germination rate and very high pollen sterility, no seed set, and very high ovary predation. It thus has very low reproductive success and fitness. Phlomis x composita nothom. trullenquei also shows low pollen germination and seed set, but these follow regular microsporogenesis. The existence of cryptic structural sterility is suggested for this taxon. The rest of the studied taxa (P. purpurea, P. lychnitis and P. x composita nothom. composita) were fertile and can support the specific or subspecific taxonomic status of P. x composita. A fixed ovule abortion pattern in the taxa with yellow flowers was found, since 'brood size' consisted just of one seed per fruit. On the contrary, P. purpurea was found to produce from one to four seeds per fruit. Some conservation implications are suggested.