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1AbstractA high-quality reference genome assembly, a biobank of diverse equine tissues from the Functional Annotation of the Animal Genome (FAANG) initiative, and incorporation of long-read sequencing technologies, have enabled efforts to build a comprehensive and tissue-specific equine transcriptome. The equine FAANG transcriptome reported here provides up to 45% improvement in transcriptome completeness across tissue types when compared to either RefSeq or Ensembl transcriptomes. This transcriptome also provides major improvements in the identification of alternatively spliced isoforms, novel noncoding genes, and 3’ transcription termination site (TTS) annotations. The equine FAANG transcriptome will empower future functional studies of important equine traits while providing future opportunities to identify allele-specific expression and differentially expressed genes across tissues.

The GaAs-like longitudinal-optical (LO) phonon frequency in hydrogenated GaAsN (x = 0.01) layers - with different H doses and similar low-energy irradiation conditions - was investigated by micro-Raman measurements in different scattering geometries and compared with those of epitaxial GaAs and as-grown GaAsN reference samples. A relaxation of the GaAs selection rules was observed, to be explained mainly on the basis of the biaxial strain affecting the layers. The evolution of the LO phonon frequency with increasing hydrogen dose was found to heavily depend on light polarization, thus suggesting that a linear relation between strain and the frequency of the GaAs-like LO phonon mode should be applied with some caution. Moreover, photoreflectance measurements in fully passivated samples of identical N concentration show that the blueshift of the GaAs-like LO frequency, characteristic of the hydrogenated structures, is dose-dependent and strictly related to the strain induced by the specific type of the dominant N-H complexes. A comparison of photoreflectance results with the finite element method calculations confirms that this dependence on the H dose is due to the gradual replacement of the N-2H complexes responsible for the electronic passivation of N with N-3H complexes, which are well known to induce an additional and sizeable lattice expansion.

We report the SERS activity of colloidal silver nanoparticles functionalized with a ligand, derived from the siderophore desferrioxamine B (desferal, DFO), an iron chelator widely used in biological and medical applications. The ligand was equipped with a sulfur-containing moiety to ensure optimal binding with silver surfaces. By means of Raman and SERS effects we monitored the route of material preparation from the modified DFO–S molecule to the colloidal aggregates. The results indicate that the functionalization of the chelating agent does not affect its binding ability towards Fe(III). The resulting functionalized silver nanoparticles are a promising SERS tag for operation in biological environments. The Fe–O stretching signature, arising when DFO–S grafted to silver nanoparticles binds Fe(III), could provide a tool for cation sensing in solution.

Raman scattering is an effective tool for the investigation of the strain state of crystalline solids. In this brief review, we show how the analysis of the GaAs-like longitudinal optical phonon frequency allowed to map the strain behavior across interfaces in planar heterostructures consisting of GaAsN wires embedded in GaAsN:H matrices. Moreover, we recently showed how the evolution of the longitudinal optical frequency with increasing H dose strongly depends on polarization geometry. In a specific geometry, we observed a relaxation of the GaAs selection rules. We also present new results which demonstrate how laser irradiation intensity–even at low levels–may affect the line shape of the GaAs-like spectral features in GaAsN hydrogenated materials.

The last decade has come across an increasing demand for theranostic biocompatible nanodevices possessing the double ability of diagnosis and therapy. In this work, we report the design, synthesis and step-by-step characterization of rationally coated gold nanostars (GNSs) for the SERS imaging and photothermal therapy of HeLa cancer cells. The nanodevices were realized by synthesizing GNSs with a seed growth approach, coating them with a controlled mixture of thiols composed of a Raman reporter and a polyethylene glycol with a terminal amino group, and then reacting these amino groups with folic acid (FA), in order to impart selectivity towards cancer cells which overexpress folate receptors on their membranes. After a complete characterization, we demonstrate that these FA-functionalized GNSs (FA-GNSs) are able to bind selectively to the membranes of HeLa cells, acting as SERS tags and allowing SERS imaging. Moreover, we demonstrate that once bound to HeLa cell membranes, FA-GNSs exhibit photothermal effect which can be exploited to kill the same cells in vitro using laser irradiation in the NIR at a very low and safe irradiance. We thus demonstrate that the FA-GNSs designed following the described approach are an efficient prototype of theranostic nanodevices.

Microstructural modifications, induced by femtosecond laser irradiation on Lithium Niobate (LN) crystals were investigated by means of optical microscopy and micro-Raman spectroscopy. Commercial z-cut congruent LN substrates were irradiated with focused ultra-short laser pulses at 810 nm. At the focus region either structural changes or material removal were observed by varying the irradiation conditions. The mapping of Raman spectrum revealed the insurgence of Raman modes, which are forbidden in the used scattering geometry. This phenomenon increases gradually by approaching the ablation region. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

We present the first growth of KTaO3:Be (6% at. in the batch) single crystals, together with photoconductivity and thermally stimulated currents studies of this material. It is probably that very small Be2+ ions (ionic radius ∼0.35 A ) mostly substitute K+(1.64 A) and bounded and/or free electronic states formation including polaronic states. As a results Be-doping effect can strongly influence phase instability and electronic properties of KTaO3. It was found that Be2+ doping leads to appreciable photocurrents already at room temperature under irradiation of the samples with photons even at energies just below the fundamental optical gap. Photoconductivity increases strongly at low temperature. Intense thermally stimulated current peaks between 15 and 100 K are probably due to the presence of shallow hole traps and polaronic centres. The obtained results are compared to past observations in pure KTaO3 and KTaO3:Li (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

We present results from Raman scattering, EPR and static magnetization measurements in CaCu 3 Ti 4 O 12 , a perovskite-related material characterized by a colossal dielectric permittivity e 0 . The investigated samples were pure and partially substituted in the octahedral Ti sites by other transition metals. The results from the pure material are interpreted in terms of the presence of delocalized Copper-holes. Substitutions in the Ti sites drastically change the magnetic properties and, most evidently in the case of Cr, also affect the Raman spectra. These effects correlate with the known suppression of the colossal e 0 after the same kind of substitutions.

Photoconductivity (PC), thermally stimulated conductivity (TSC), photoluminescence (PL), thermoluminescence (TL), and electron spin resonance (ESR) measurements have been made on single crystals of potassium tantalate over the temperature range 4.2–290 K. We revealed two sorts of O− shallow hole centers which are responsible for the two temperature regions of PL and PC enhancement: T

It is shown that doping the highly polarizable KTaO3 perovskite simultaneously by Li and Nb (K1−xLixTa1−yNbyO3, KLTN) gives rise to new impressive dipole ordering effects, very unusual physical properties and strong responses with respect to doping parameters. Besides, KLTN has outstanding perspectives of application in electrically controlled holographic and compositionally graded pyroelectric devices.

We made Thermally Stimulated Conductivity (TSC), Thermoluminescence (TL) and Electron Spin Resonance (ESR) measurements on single crystals of potassium tantalate in the temperature range 4.2-290 v K. We revealed two sorts of O m shallow hole centers which are responsible for Photoconductivity (PC) and Photoluminescence (PL) enhancement. Both O m centers were identified by their ESR spectra. We show that these centers serve as radiative electron-hole recombination centers. The measurements of TSC and TL after UV irradiation revealed several glow peaks at temperatures 18-30 v K and 65-70 v K. Both TSC and TL are attributed to the thermal ionization of the same shallow donor centers related with oxygen vacancies. Experimental data were treated in a simple one-trap/one-recombination center model, which takes into account the presence of "thermally disconnected" deep electron traps.

KTaO 3 with small amount ( x < 0.01) of Li and simultaneously diluted by Nb (K 1 m x Li x Ta y Nb 1 m y O 3 , KLTN) reveals original dipole ordering structural effects. Small Nb co-dopings ( y < 0.007) enhance the trend of the Li + off-centers related subsystem towards cooperative ordering and order-disorder phase transitions. At 0.01 < y < 0.05 the intrigue features of displacive and order-disorder transitions reveal. The most interesting features are the appearance of soft-mode driven ferroelectric transitions accompanied by a Li + off-centers system freezing followed by a reentrant dipole glass-like phase formation, and the emergence of a narrow transition with giant magnitude of l '(T). Evidences of reentrant dipole glass formation were observed in KTa 0.981 Nb 0.019 O 3 too. A possible model developed is based on the Li-Nb polar clusters, local configuration instabilities and superparaelectricity conceptions.

Raman investigations on single crystals of K 1-x Li x Ta 1-y Nb y O 3 were performed to identify structural effects arising from the simultaneous presence of off-centre Li and Nb ions in the incipient ferroelectric KTaO 3 . Two soft-mode transitions were evidenced at 45 K and 30 K in a sample with x = 0.0014 and y = 0.024 after both zero-field and field cooling. These temperatures are close to the maximum and to the extrapolated Curie temperature for non-relaxing permittivity reported in the same system. A sample with x = 0.0028 and y = 0.013 displayed a ferroelectric transition just below 30 K only after field cooling, also being consistent with permittivity data.

Li admixture greatly enhances n-type photoconductivity of KTaO3 crystals. Thermally stimulated current experiments indicate that this phenomenon is related with the presence of hole-trapping levels with depths of 50–100 meV. This is in good agreement with recent energy structure calculations showing the existence of levels at these energies above the top of the VB, due to perturbed O2- p-states. The study of visible photoluminescence and thermo-luminescence shows that the hole-trapping centre also controls the emission process. We conclude in favour of radiative recombination involving O−Ta4+polaron pairs. Keywords: ferroelectric perovskites: photoconductivity

Raman observations in the region of the TO 1 soft mode were performed on samples of K 1-x Li x Ta 1-y Nb y O 3 , having x in the range 0.6 - 1.0 % mol. and y in the range 0.2 - 0.3 % mol. The analysis of temperature evolution and spectral shape allowed to evidence the spontaneous splitting of the TO 1 mode and its relative stiffness below 50 K, accompanied by an abrupt increase of first order scattering strengths. Such effects are not observed when Li or Nb are separately introduced in the KTaO 3 matrix, at the given concentrations.

Raman scattering observations were performed on samples of K1-xLixTa1-yNbyO3, with x in the range 0.6-1.0 mol% and y in the range 0.2-0.3 mol%. Concentrations of Li and Nb, determined by analytical methods, were below the known thresholds at which these substituents can separately induce a ferroelectric transition in the quantum paraelectric KTaO3. The temperature evolution of TO1 and TO4 spectra was monitored. The results show a critical behaviour below 50 K, characterized by an abrupt increase of first-order scattering strengths and by spontaneous splitting of the non-softening TO1 mode. From our data, we infer the occurrence of a ferroelectric phase transition of order-disorder character. This proves that small additions of Nb enhance the tendency of the Li subsystem towards cooperative ordering in the KTaO3 matrix.

Visible photoluminescence in K1−xLixTaO3 was found to have similar spectral features but a large increase of emission yield with respect to KTaO3. Studying the temperature dependence of the phenomena and its correlation with photoconductivity, we found direct support for a process in which the emission is due to pair recombination of trapped electron and hole centers, Ta4+ and O−, intrinsic to the matrix.

The temperature evolution of TO1 Raman spectra was investigated in single crystals of K1−xLixTa1−yNbyO3:Cu with different Li and Nb amounts. Auxiliary observations of TO4 spectra were also performed. In a sample with x = 0·002 and y = 0·025 and containing 190 ppm of Cu, the results indicate a clear-cut transition to an ordered phase around 55 K, in good agreement with previous findings from dielectric measurements in the same crystal. However, no evidence was found of a role of Cu in this structural modification. Samples with x = 0·01 and y = 0·003 revealed features of an order-disorder phase transition around 45 K, irrespective of the presence of Cu.

We present the results of experiments performed on K1-xLixTaO3 as well as on Nb-doped and nominally pure KTaO3 single crystals, in which we compared observations of thermally stimulated currents and photoconductivity. In the Li-doped compounds, the large enhancement of conductivity caused by ultraviolet excitation at low temperature was found to correlate with the filling of shallow trapping centres, giving intense charge release below 30-40 K. No sign of a corresponding release was shown by pure or Nb-doped KTaO3, consistently with a very low yield of photocurrent which one observes in these cases. The depth of the trapping levels in K1-xLixTaO3 crystals was found to be between 50 and 70 meV. On the basis of past models and recent calculations, these levels can be identified with hole traps, originating from the perturbation of O2- states at the top of the valence band. They are a plausible source of enhanced photoconductivity, via the quenching of electron-hole recombination.

Experiments on photoconductivity and thermally stimulated currents were performed on Li-doped KTaO3 single crystals. The large enhancement of conductivity, caused by UV excitation at low temperature was found to correlate with a subsequent release of trapped charge between 30 and 40 K. No corresponding release was shown by pure KTaO3, consistently with a very low yield of photoconduction. It is concluded that the presence of hole traps, with the consequent quenching of electron-hole recombination, is at the origin of the photoconductive response of K1−xLixTaO3.

A study of blue-green photoluminescence of K1-x Li x TaO3 single crystals, under UV irradiation, was performed in the range 15–20 K. It was shown that the emission is strongly enhanced and thermally more stable with respect to pure KTaO3, up to ∼40 K. Above this point the yield of emission decreases abruptly with an Arrhenius-like behaviour controlled by an activation energy of 70–100 meV. After low temperature excitation, a thermoluminescence spectrally very similar to PL and giving rise to a glow peak around 30K is also observed. Correlations with recent results on photoconductivity and thermally stimulated currents are illustrated. An argument in favour of close-pair recombinations between Ta4+ and O− centers is proposed.

Photocurrent and Hall effect measurements were performed on ${\mathrm{K}}_{0.984}{\mathrm{Li}}_{0.016}{\mathrm{TaO}}_{3}$ and ${\mathrm{K}}_{0.966}{\mathrm{Li}}_{0.034}{\mathrm{TaO}}_{3}$ single crystals under illumination with 514.5-nm and UV light. The currents observed are carried by electrons, whose mobility does not undergo large variations on cooling across the dipole-glass freezing temperature ${T}_{f}.$ The sharp increase of photocurrent occurring in the polar phase is primarily due to enhancement of carrier density. The effect is much larger after field cooling, being accompanied in this case by persistent currents. The present results lead us to conclude that hole traps with vanishing cross section for electron recombination are active below ${T}_{f}.$

X-ray small angle scattering measurements on silicate and borate glasses are described and the contrasting effects of inhomogeneities such as density fluctuations and alkali microsegregation are discussed. The consequences of microstructure for ionic diffusion, the mixed alkali effect (MAE), thermal expansion, glass fracture and polishing are considered, making use of some recent results of molecular dynamic simulations and oxygen X-ray absorption fine structure measurements.

Photoinduced effects were studied in , making use of birefringence and second-harmonic generation as probes of structural modifications induced by illumination at 2.4 eV. It is shown that photoinduced charges have no direct influence on the size and orientational freedom of polar microregions. Quenching of the polar order by illumination is only observed in the presence of an external field and it is consistent with the build-up of a depoling field, owing to space-charge formation. Light of energy below 2 eV is not effective by itself, but it can be if the sample is pre-sensitized with photons of higher energy.

Observations of the soft-mode Raman spectrum, performed in poled and unpoled KTa0.976Nb0.024O3, show that the polar transition in this sample is still characterized by a substantial degree of order, in contrast to the frozen dipole-glass behaviour of a K0.984Li0.016TaO3 sample. Results of second-harmonic generation indicate that this ordering may scale up to fairly large dimensions, even in the spontaneous case.

Raman investigations have been performed on K0.984Li0.016TaO3 and KTa0.976Nb0.024O3 single crystals, in order to follow the peculiarities of non-ferroelectric phonons, which may be indicative of a different evolution of microscopic order during the polar transition. Specific features in the Nb case confirm a ferroelectric behaviour, whereas in the Li-doped sample the results are in agreement with a dipole glass transition.

We report birefringence and second-harmonic-generation measurements in ${\mathrm{K}}_{0.984}$${\mathrm{Li}}_{0.016}$${\mathrm{TaO}}_{3}$ at temperatures between 55 and 10 K. On cooling, the local spontaneous polarization grows from \ensuremath{\approxeq}1 to 30 mC/${\mathrm{m}}^{2}$. We find, however, that its correlation length obtains the value of \ensuremath{\approxeq}8 nm at 55 K and remains unchanged on further cooling. It appears that a ``frozen'' polar length scale arises from the interaction of the Li dipoles well above the usually defined transition temperature (\ensuremath{\approxeq}36 K).

GaAsN/GaAsN:H heterostructures were made by an in-plane selective hydrogen incorporation controlled by H-opaque metallic masks. The strain field and hydrogen distributions in GaAsN micro-sized wires thus obtained have been mapped by an all optical procedure that combines micro-Raman scattering and photoreflectance spectroscopy. The strain field is related to the formation of N-H complexes along the hydrogen diffusion profile with an ensuing expansion of the GaAsN lattice whose patterning generates an anisotropic stress in the sample growth plane. These results highlight a powerful non-invasive tool to simultaneously determine both the H diffusion profile and the related strain field distribution.

Low frequency Raman and quasi-elastic light scattering measurements were performed in KTa0.976Nb0.024O3. Near the transition temperature, data were analyzed with the help of a simple soft mode-relaxor coupling model to take into account the presence of the wide central component. At lower temperatures the soft-mode line hardens and splits, thus characterizing the ferroelectric transition. A distinctive feature is the uncomplete softening of the TO1 naked frequency, despite the second order character of the transition, resulting from birefringence. The observed phenomena could be interpreted in terms of a critical dynamics in which both the order-disorder and displacive aspects are present.

Recently, very intriguing dipole-ordering phenomena near the critical temperature and down into the low temperature phase were reported for K{sub 1-x}Li{sub x}Ta{sub 1-y}Nb{sub y}O{sub 3}. The understanding of these processes is a crucial aspect of basic research and applications. In the present work, we report on Raman experiments in K{sub 1-x}Li{sub x}Ta{sub 1-y}Nb{sub y}O{sub 3} crystals with x -0.004 and y -0.031. Systematic analysis of TO{sub 1} and TO{sub 4} spectra within the temperature range of 17-150 K was performed. All the measurements were performed after both zero-field and field cooling. The results enable us to gain new evidence of the competition between long-range order and the Li-related dipole glasslike subsystem.

We report on Raman scattering experiments on InAs/Al(x)Ga(1-x)As quantum dot heterostructures with 0 0, we detected several lines originating from the Al(x)Ga(1-x)As alloy. These can be related to scattering from GaAs-like and AlAs-like phonons with q congruent to 0, and weaker scattering from disorder-activated phonons with q not equal 0. In particular, we identified a line at similar to 250 cm(-1) as due to disorder-activated longitudinal optical phonons in the alloy. This conclusion is different than the attribution of this line to scattering from dots and, consequently, we do not recognize the possibility of deriving any information about the actual composition of the dots from an analysis of this line as proposed by other authors.

The insertion of mitochondrial DNA in the nuclear genome generates numts, nuclear sequences of mitochondrial origin. In the horse reference genome, we identified 82 numts and showed that the entire horse mitochondrial DNA is represented as numts without gross bias. Numts were inserted in the horse nuclear genome at random sites and were probably generated during the repair of DNA double-strand breaks. We then analysed 12 numt loci in 20 unrelated horses and found that null alleles, lacking the mitochondrial DNA insertion, were present at six of these loci. At some loci, the null allele is prevalent in the sample analysed, suggesting that, in the horse population, the number of numt loci may be higher than 82 present in the reference genome. Contrary to humans, the insertion polymorphism of numts is extremely frequent in the horse population, supporting the hypothesis that the genome of this species is in a rapidly evolving state.

Horses, asses and zebras belong to the genus Equus and are the only extant species of the family Equidae in the order Perissodactyla. In a previous work we demonstrated that a key factor in the rapid karyotypic evolution of this genus was evolutionary centromere repositioning, that is, the shift of the centromeric function to a new position without alteration of the order of markers along the chromosome. In search of previously undiscovered evolutionarily new centromeres, we traced the phylogeny of horse chromosome 5, analyzing the order of BAC markers, derived from a horse genomic library, in 7 Equus species (E. caballus, E. hemionus onager, E. kiang, E. asinus, E. grevyi, E. burchelli and E. zebra hartmannae). This analysis showed that repositioned centromeres are present in E. asinus (domestic donkey, EAS) chromosome 16 and in E. burchelli (Burchell's zebra, EBU) chromosome 17, confirming that centromere repositioning is a strikingly frequent phenomenon in this genus. The observation that the neocentromeres in EAS16 and EBU17 are in the same chromosomal position suggests that they may derive from the same event and therefore, E. asinus and E. burchelli may be more closely related than previously proposed; alternatively, 2 centromere repositioning events, involving the same chromosomal region, may have occurred independently in different lineages, pointing to the possible existence of hot spots for neocentromere formation. Our comparative analysis also showed that, while E. caballus chromosome 5 seems to represent the ancestral configuration, centric fission followed by independent fusion events gave rise to 3 different submetacentric chromosomes in other Equus lineages.

We report on recent findings obtained through Raman scattering, second harmonic generation and linear birefringence on the polar phase of doped KTaO3. At low temperature, the polar coherence length ranges from a few nanometers to 20 nm for 1.6% and 6% Li doping, respectively and shows no criticality. Comparable figures are found for the case of 12% Na doping. The evolution of low energy Raman spectra and the behaviour under a poling field provides further evidence of phenomena which limit the growth and cooperative ordering of polar microregions.

Etude du rendement de generation de la seconde harmonique et de la birefringence. On en conclut qu'en dessous de la temperature de solidification T f , les deplacements polaires de KTaO 3 :Li sont correles sur des distances qui augmentent de facon continue avec la concentration en dopant

Low-frequency Raman scattering in the mixed perovskite KTaO3 (Na 12%) is shown to give information on the correlation length of the local order parameter which is in agreement with that obtained by combined measurements of linear birefringence and second harmonic generation. Accordingly, the behavior of this system is interpreted in terms of a frustrated structural transition, characterized by freezing of the polar domain dimension (300A) in the low temperature region.

The paper reports on the first crystal growth and Raman scattering studies in K0.992Rb0.008Ta0.96Nb0.04O3 (KRTN) and KTaO3:Rb (3% mol. in the melt), in which Rb+ ions (ionic radius 1.47 angstrom) substitute K+(1.33 angstrom). The experiments were performed in the range 10-300 K and focused on the behavior of TO1 and TO4 modes. The results confirm indications by previous dielectric permittivity data about the ferroelectric nature of the phase transition in KRTN. It appears that a small amount of Rb changes the character of the phase transition induced by Nb from mainly displacive to mainly order-disorder, whereas no evidence of ferroelectricity is revealed in the KTaO3:Rb sample.

The paper reports on Raman scattering experiments in pure, Mg-doped and Fe-doped single crystals of lithium niobate. The measurements were carried out in 90degrees geometry at several laser beam intensities, and in several polarization arrangements. The possible occurrence of light-induced polarization-anisotropic scattering, and its effects on Raman spectra, were checked by simultaneously measuring the time dependence of the laser beam intensity transmitted by the sample with unchanged polarization, and the time dependence of the intensity of Raman lines from vibrational modes of known symmetry. The results give no indication of any effect of photorefractive activity on Raman observations in our pure and Mg-doped samples. On the contrary, in Fe-doped lithium niobate the build-up of light-induced o-e scattering strongly affected the relative intensities of Raman lines in specific experimental arrangements. We discuss the possible application of these effects to the characterization of lithium-niobate-based materials with strong photovoltaic and photorefractive activity.

The GaAs-like longitudinal optical phonon frequency in two hydrogenated GaAs1-N-x(x)/GaAs1-N-x(x):H microwire heterostructures-with similar N concentration, but different H dose and implantation conditions-has been investigated by micro-Raman mapping. In the case of GaAs0.991N0.009 wires embedded in barriers where GaAs-like properties are recovered through H irradiation, the phonon frequency in the barriers undergoes a blue shift with respect to the wires. In GaAs0.992N0.008 wires embedded in less hydrogenated barriers, the phonon frequency exhibits an opposite behavior (red shift). Strain, disorder, phonon localization effects induced by H-irradiation on the GaAs-like phonon frequency are discussed and related to different types of N-H complexes formed in the hydrogenated barriers. It is shown that the red (blue) character of the frequency shift is related to the dominant N-2H (N-3H) type of complexes. Moreover, for specific experimental conditions, an all-optical determination of the uniaxial strain field is obtained. This may improve the design of recently presented devices that exploit the correlation between uniaxial stress and the degree of polarization of photoluminescence. (C) 2014 AIP Publishing LLC.

Gene amplification is one of the most frequent genome anomalies observed in tumor cells, whereas it has never been detected in cells of normal origin. A large body of evidence indicates that DNA double-strand breaks (DSBs) play a key role in initiating gene amplification. In mammals, DSBs are mainly repaired through the nonhomologous end-joining pathway (NHEJ) that requires a functional DNA-dependent protein kinase catalytic subunit (DNA-PKcs). In rodent cell lines, N-(phosphonacetyl)-L-aspartate (PALA) resistance is considered a measure of gene amplification because it is mainly attributable to amplification of the carbamyl-P-synthetase aspartate transcarbamylase dihydro-orotase (CAD) gene. In this paper we show that the radiosensitive hamster cell line V3, which is defective in DSB repair because of a mutation in the DNA-PKcs gene, displays also an increased frequency of gene amplification. In these cells, we found that the amplification of the CAD gene occurs with a frequency and a rate more than one order of magnitude higher than in control cell lines, although it relies on the same mechanisms. When the same analysis was performed in mouse embryo fibroblasts (MEFs) obtained from animals in which the DNA-PKcs gene was ablated by homologous recombination, a higher frequency of amplification compared with the controls was found only after cellular immortalization. In primary DNA-PKcs(-/-) MEFs, PALA treatment induced a block in the cell cycle, and no PALA-resistant clones were found. Our results indicate that the lack of DNA-PKcs increases the probability that gene amplification occurs in a genetic background already permissive, like that of immortalized cells, although it is not sufficient to make normal cells able to amplify.

Dielectric permittivity and Raman-scattering studies reveal unconventional dipole ordering and structural effects that arise in the incipient ferroelectric ${\mathrm{KTaO}}_{3}$ due to the simultaneous presence of off-center ${\mathrm{Li}}^{+}$ and ${\mathrm{Nb}}^{5+}$ ions. A soft-mode-driven transition into a ferroelectric phase accompanied by the formation of a dipole glass in the ${\mathrm{Li}}^{+}$ subsystem was identified at 39 K in a sample of composition ${\mathrm{K}}_{0.9986}{\mathrm{Li}}_{0.0014}{\mathrm{Ta}}_{0.988}{\mathrm{Nb}}_{0.012}{\mathrm{O}}_{3}.$ A second soft-mode transition was found at 30 K, whereas a transition into a phase identified as a ``reentrant dipolar glasslike state'' was observed at 15 K. Such a sequence of phases, diordered--long range ordered--reentrant glass, already known for disordered ferromagnets, is here reported for a highly polarizable matrix with soft modes.

Waveguides obtained by proton exchange in LiNbO3 were characterized by Secondary Ion Mass Spectrometry and m-lines technique. Additional micro-Raman investigations evidenced marked changes in the spectra of the waveguide with respect to the substrate. This suggests that micro-Raman spectroscopy may constitute a direct non-destructive method to determine the depth of the exchanged layer, with a limit which is set by the diffraction-limited spot size.

Cathelicidins are precursors of defense peptides of the innate immunity and are widespread in mammals. Their structure comprises a conserved prepropiece and an antimicrobial domain that is structurally varied both intra- and inter-species. We investigated the complexity of the cathelicidin family in horse by a reverse transcription-PCR-based cloning strategy of myeloid mRNA and by Southern and Western analyses. Three novel cathelicidin sequences were deduced from bone marrow mRNA and designated equine cathelicidins eCATH-1, eCATH-2 and eCATH-3. Putative antimicrobial domains of 26, 27 and 40 residues with no significant sequence homology to other peptides were inferred at the C-terminus of the sequences. Southern analysis of genomic DNA using a probe based on the cathelicidin-conserved propiece revealed a polymorphic DNA region with several hybridization-positive fragments and suggested the presence of additional genes. A null eCATH-1 allele was also demonstrated with a frequency of 0.71 in the horse population analyzed and low amounts of eCATH-1-specific mRNA were found in myeloid cells of gene-positive animals. A Western analysis using antibodies to synthetic eCATH peptides revealed the presence of eCATH-2 and eCATH-3 propeptides, but not of eCATH-1-related polypeptides, in horse neutrophil granules and in the secretions of phorbol myristate acetate-stimulated neutrophils. These results thus suggest that eCATH-2 and eCATH-3 are functional genes, whereas eCATH-1 is unable to encode a polypeptide.

(T2AG3) repeats comprise the telomeres of human chromosomes and also are present at interstitial locations. Using a long synthetic (T2AG3)n probe, we have localized telomere-like repeats at several internal sites on human chromosomes.