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Gold nanoparticles are emerging as promising agents for various areas of material science as well as nanotechnology, electronics and medicine. The interest in this material is provided due to its unique optical, electronic and molecular-recognition properties. This paper presents results of preparation, characterization and biofunctionalization of gold nanoparticles. Nanoparticles have been conjugated with the cholesterol oxidase enzyme in order to prepare the active element for biosensors. Cholesterol oxidase is one of the most important analytical enzyme, used for cholesterol assay in clinical diagnostics, and there is still a necessity in improvement of existing analytical techniques, including bio-nanotechnological approaches based on modern nanosystems. The prepared bio-nanosystem was characterized by the enzyme activity test. Obtained results showed a stable binding of the enzyme with nanoparticles and preserved the bioactivity approves which gives possibility to use the prepared bio-nanosystems for analytical purposes. The Surface Plazmon Resonance and the Surface Enhanced Raman Scattering as specific for nanocurriers effects were observed what enable us to research the oscillation spectra of enzyme. These spectra were compared with ones obtained by IR-spectroscopy. The vibrational lines are attributed to chemical functional groups existing in enzyme, for example, amino acids, amide groups as well as flavin – adenine dinucleotide cholesterol oxidase prosthetic group. By this way the identified spectral lines can be used as a distinguishing mark of enzyme.

Experimental results of the magnetotransport measurements (longitudinal magnetoresistance ${R}_{xx}$ and the Hall resistance ${R}_{xy}$) are presented over a wide interval of temperatures for several samples of ${\mathrm{Hg}}_{1\ensuremath{-}x}{\mathrm{Cd}}_{x}\mathrm{Te}$ ($x\ensuremath{\approx}0.13--0.15$) grown by MBE---thin layers (thickness about 100 nm) strained and not strained and thick ones with thickness about $1\phantom{\rule{0.28em}{0ex}}\ensuremath{\mu}\mathrm{m}$. An amazing temperature stability of the SdH-oscillation period and amplitude is observed in the entire temperature interval of measurements up to 50 K. Moreover, the quantum Hall effect (QHE) behavior of the Hall resistance is registered in the same temperature interval. These peculiarities of the ${R}_{xx}$ and ${R}_{xy}$ for strained thin layers are interpreted using quantum Hall conductivity (QHC) on topologically protected surface states (TPSS) [C. Br\"une et al., Phys. Rev. Lett. 106, 126803 (2011)]. In the case of not strained layers it is assumed that the QHC on the TPSS (or on the resonant interface states) contributes also to the conductance of the bulk samples.

In the cells of Haemanthus albiflos leaf epidermis there are structures containing lipids analogous to “elaioplasts” (Wakker in Jahrb F Wiss Bot 19:423–496, 1888). Ultrastructural analysis has shown that they are cytoplasmic domains—lipotubuloids, since they exhibit all the features of Ornithogalum umbellatum lipotubuloids. They are composed of numerous lipid bodies surrounded by microtubules, ER cisternae and vesicles, some mitochondria, Golgi structures, and microbodies. In the center of some lipotubuloids there are also autolytic vacuoles. Microtubules adjacent to H. albiflos lipid bodies were revealed only when taxol preincubation was used before fixing the epidermis in the mixture of glutaraldehyde and OsO4. The presence of tubulin in H. albiflos and O. umbellatum lipotubuloids was confirmed with use of the immunogold method involving antibodies against tubulin α. It is possible that the association of microtubules with lipid bodies may be more common than originally thought, but it is difficult to reveal due to the methodological problems.

Our research is motivated in the first line by the necessity to have the total control of the vacancies which appear during the growth of mercury telluride crystals. As it is known, this material is very important for the IR devices. We present a non-destructive method for quantitative determining the vacancy concentration in the lattice of Hg-based semiconductor alloys with tetrahedral structure. The method is based on the identification of additional vibrational modes (AVM) induced by lattice deformations in the far infrared (FIR) reflectivity spectrum. Although the method is restricted by sensitivity limitations, recent FIR experimental data carried out on HgZnTe and HgCdTe samples containing Hg-vacancies confirmed the presence of AVMs induced by Hg-vacancies in as-grown crystals. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The presence of oxygen impurity in semiconducting materials affects the electrical properties of crystals and significantly limits their application. To remove oxygen impurity, ultra-pure hydrogen is used while growing Te-containing crystals such as CdTe, CdZnTe, and ZnTe. The hydrogenation of CdTe crystals is a technological process that purifies the basic material from oxygen, mainly cadmium and tellurium oxide compounds incorporated in CdTe crystalline lattice. In the present work we analyses the deformations induced by hydrogen and oxygen atoms in CdTe crystals looking at their influence on the near fundamental band (NFB), middle infrared (MIR) and far infrared (FIR) reflectivity spectra as well as on cathodoluminescence (CL) spectra. Comparison of the hydrogenated CdTe phonon structure profiles confirms the presence of hydrogen atoms bounded inside the lattice. The possible localization of hydrogen and oxygen ions within the tetrahedron coordinated lattice is discussed in the framework of a model that shows a good agreement with recent NFB, MIR and FIR experiments carried out on hydrogenated CdTe crystals. Measured reflection spectra in the wavelength range 190-1400 nm (NFB) indicate the appearance in CdTe(HM) and CdTe(HL) of additional maxima at 966 nm related to the electron transitions from level about 0.2 eV above the valence band. The CL spectra confirmed existence of this electron level. We present a possible H2 alignment similar to the single H model i.e., over the face (at about 0.38 A). For this model the angle from the central atom to the H atoms is equal to 64° which is also close to the bonding angle of CdH2 (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The work presents far-and middle-infrared reflectivity spectra collected with synchrotron radiation on specially prepared CdTe-monocrystals in the temperature region of 30-300 K. The investigated samples were of three different types characterized by the three different levels of hydrogenation – strong, middle and the low ones. In order to interpret the experimental data, the imaginary part of the dielectric function was evaluated by means of Kramers-Kronig transformation. To determine quantitatively the influence of hydrogen atoms on the phonon and vibrational spectra of hydrogenated CdTe crystals we used the special statistical model proposed in this paper. This model takes into account the tetrahedron as the basic structural unit and distinguishes the contribution of the hydrogen bearing tetrahedra from the contribution of the hydrogen free ones to the crystal phonon spectra. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

In the present work the deformations induced by hydrogen and oxygen atoms in CdTe crystals have been analyzed looking at their influence on the middle infrared (MIR) and far infrared (FIR) reflectivity spectra. Comparison of the hydrogenated CdTe phonon structure profiles confirms the presence of hydrogen atoms bounded inside the lattice. The possible localization of hydrogen and oxygen ions within the tetrahedron coordinated lattice is discussed in the framework of a model that shows a good agreement with recent MIR experiments carried out on hydrogenated CdTe crystals.

This work presents result of far-infrared spectra obtained (by synchrotron radiation as well as by the mercury lamp) from samples ZnxCd1−xTe (x = 0.056, 0.11, 0.16, 0.22, 0.28, 0.7). The results are obtained from two different polarizations for planes (1 1 1) and (1 1 0). The interpretation of this result is based on the model of five tetrahedron cells.

Quaternary solid solutions ZnxCdyHg1−x−yTe (0

In this paper we describe a practical implementation of an original apparatus for pulsed laser deposition (PLD) of thin films of mixed crystal of the II–VI semiconducting compounds and their layered structures such as superlattices. We report also on preliminary results of deposition of the films and their basic structural properties.

Magnetophonon resonance (MPR) was studied in Mn 0.095 Cd 0.09 Hg 0.815 Te and Mn 0.04 Cd 0.09 Hg 0.77 Te quaternary solid solution. The fundamental line of MPR is observed at the magnetic field of about 10 T. This value is considerably higher than that for Zn x Cd y Hg 1− x − y Te of the same energy gap. The interpretation of this effect is based on sp–d exchange interaction between the spin of free carriers and the localized magnetic moments of the Mn 2+ ions.

Magnetophonon resonance was found to manifest itself in Mn 0.095 Cd 0.089 Hg 0.816 Te four-component solid solution. The main maximum is located at a magnetic field of about 8 T, which is considerably higher than in Zn x Cd y Hg 1-x-y Te of the same energy gap. Interpretation of this effect is based on s, p-d exchange interaction between the spin of free carriers and the localized magnetic moments of the Mn 2+ ions.

The study of bulk phonons in thin films is limited due to the low energy of far-infrared sources. The infrared reflection–absorption spectroscopy (IRAS) technique has, therefore, been developed. In the case of incidence deviating from normal two states of polarization of incident light should be taken into consideration. The application of approximation of ultra thin films enables to obtain the simple relations Δ R / R 0 between the change of reflectivity of a metal plate covered with a film and that of the metal substrate. Δ R / R 0 has been obtained for two polarizations, namely: s and p. The present research has demonstrated that this method proved to be particularly usable for the multimode crystals where the oscillator strength is distributed on several modes. The IRAS technique has been applied to the Zn x Cd y Hg 1− x − y Te (ZMCT) thin films. The frequencies of LO and TO phonons were determined by comparing the theoretical and experimental spectra.

The phonon and electron subsystems in the quaternary solid solutions of (ZMCT) were studied by means of Raman scattering and magnetophonon resonance. The Raman spectra for several compositions confirm that the phonon spectra exhibit three-mode behaviour. The cluster mode has also been observed. Four kinds of LO phonon (with HgTe-like, CdTe-like and ZnTe-like sublattices and ZnTe clusters) participate in the electron-phonon interaction. Four types of one-phonon magnetophonon resonance and two types of magnetophonon resonance on the difference of phonon frequencies have been observed. The peculiarities of the electron transport in these lattices are discussed.

The magnetophonon resonance in a multimode crystal of the solid solution ZnxCdyHg1−x−yTe (x=0.08, y=0.11) was investigated in the temperature interval from 77 to 200 K. To interpret the obtained structure of the magnetophonon resonance spectrum, the phonon modes of three compositions of this solid solution were studied by the Raman scattering method. The results presented confirm the three-mode behavior (excluding cluster modes) of the phonon spectrum of the solid solutions of this class. The complicated structure of the magnetophonon resonance bands is interpreted on the basis of the values obtained for the phonon frequencies. The characteristic features of electron transport in such a lattice are shown.

The Raman spectra for three compositions of Zn x Cd y Hg 1-x-y Te (ZMCT) solid solution were obtained at 300 K. The experimental method allowed us to observe TO-phonon lines. The comparison of the spectra for compositions with x = 0.02, y = 0.7 and x = 0.12, y = 0.17 shows the appearance of additional lines at 163 and 175 cm -1 besides two lines which are observed in the range 120 to 150 cm -1 . Far Infrared Reflection Spectra (FIRS) were obtained for five compositions. Theoretical models for three modes of the four-component solid solution were constructed for the interpretation of the FIRS spectra of ZMCT. We obtained good agreement between the results of RS and FIRS which allowed us to determine the LO- and TO-phonon frequencies for HgTe-, CdTe- and ZnTe-like lattices.

To understand and interpret the experimental data on the phonon spectra of the solid solutions, it is necessary to describe mathematically the non-regular distribution of atoms in their lattices. It appears that such description is possible in case of the strongly stochastically homogenous distribution which requires a great number of atoms and very carefully mixed alloys. These conditions are generally fulfilled in case of high quality homogenous semiconductor solid solutions of the III–V and II–VI semiconductor compounds. In this case, we can use the Bernoulli relation describing probability of the occurrence of one n equivalent event which can be applied, to the probability of finding one from n configurations in the solid solution lattice. The results described in this paper for ternary HgCdTe and GaAsP as well as quaternary ZnCdHgTe can provide an affirmative answer to the question: whether stochastic geometry, e.g., the Bernoulli relation, is enough to describe the observed phonon spectra.

16-Mercaptohexadecanoic acid (MHDA) and tripeptide glutathione conjugated with gold nanoparticles (Au-NPs) are characterized by Fourier Transform InfaRared (FTIR) spectroscopy combined with Surface-enhanced Raman scattering (SERS) spectroscopy. Surface Plasmon Resonance (SPR) technique based on FTIR spectroscopy has become an important tool in biophysics, which is perspective for the study of organic compounds. FTIR-spectra of MHDA shows the line at 2500 cm-1 attributed to thiol group which is modified by presence of Au-NPs, suggesting the formation of bond between thiol group and gold. We also can observe the peaks originate from characteristic chemical group. A Raman spectrum of the same sample is also promising. Our preliminary experiments confirm that SERS-effect takes place for MHDA connected with Au-NPs and enable us to detected small number (less than 106 cm-2) of MHDA molecules. Combination of spectroscopy methods: FTIR and SERS – enable to study optical properties of Au- NPs and immobilized bio-molecules in context of a bio-nano-sensors., {"references":["S.J. Guo, E.K. Wang, \"Synthesis and electrochemical applications of\ngold nanoparticles,\" Analytica Chimica Acta, Vol. 598, 2007, pp. 181-\n192.","Liu, D.Leech, H. Ju, \"Application of Colloidal Gold in Protein\nImmobilization, Electron Transfer, and Biosensing,\" Analytical Letters,\nVol. 36, , 2003, pp. 1-19.","I. H. El-Sayed, X.Huang, M.A. El-Sayed, \"Surface plasmon resonance\nscattering and absorption of anti-EGFR antibody conjugated gold\nnanoparticles in cancer diagnostics: applications in oral cancer,\" Nano\nLetters. Vol. 5, 2005, pp. 829-834.","M. Hu, J. Chen, ZY. Li, L. Au, G.V. Hartland, X. Li, M. Marquez, Y.\nXia, \"Gold nanostructures: engineering their plasmonic properties for\nbiomedical applications, \"Chemical Society Reviews, Vol. 35, 2006,\npp.1084-1094.","R.J. Silbey, R.A. Alberty, and M. G. Bawendi, Physical Chemistry, John\nWiley & Sons Ltd., New York, 2004.","R. Aroca, Surface Enhanced Vibrational Spectroscopy, John Wiley &\nSons Ltd., Chichester, 2006.","A.B. Descalzo, R. Mart├¡nez-M├í├▒ez, F. Sancen├│n, K. Hoffmann, K.\nRurack, \"Hybrid Nanoapatite by Polysaccharide Nanogel-templated\nMineralization,\" Angewandte Chemie International Edition, Vol.45,\n2006, pp. 5924-5948 2006.","J. Kimling, M. Maier, B. Okenve, V. Kotaidis, H. Ballot, A. Plech,\n\"Turkevich Method for Gold Nanoparticle Synthesis Revisited,\" Journal\nPhysical Chemistry B, Vol. 110, 2006, pp. 15700-15707.","N. Stasyuk, R. Serkiz, S. Mudry, G. Gayda, A. Zakalskiy, Y.\nKoval-chuk, M. Gonchar, M. Nisnevitch, \"Recombinant human arginase\nI immobilized on gold and silver nanoparticles: preparation and\nproperties,\" Nanotechnology Development, Vol.1, 2011, p. 11-15. S.\n[10] V. Leff, L. Brandt, J. R. Heath, \"Synthesis and Characterization of\nHydrophobic, Organically-Soluble Gold Nanocrystals Functionalized\nwith Primary Amines,\" Langmuir, Vol. 12, 1996, pp. 4723-4730.\n[11] H.Shayani-Jam,D.Nematollahi,\"Electrochemical evidences in oxidation\nof acetaminophen in the presence of glutathione and N-acetylcysteine,\"\nChemical Communications, Vol. 46, 2009, pp. 409-411.\n[12] M. Hasan, D. Bethell, M. Brust, \"The fate of sulfur-bound hydrogen on\nformation of self-assembled thiol monolayers on gold: (1)H NMR\nspectroscopic evidence from solutions of gold clusters,\" Journal of the\nAmerican Chemical Society, Vol. 124, 2002, pp. 1132-1133.\n[13] M. J. Hostetler, J.J. Stokes, R.W. Murray, \"Infrared Spectroscopy of\nThree-Dimensional Self-Assembled Monolayers: N-Alkanethiolate\nMonolayers on Gold Cluster Compounds,\" Langmuir, Vol. 12, 1996, pp.\n3604-3612.\n[14] Y. Sahoo, H. Pizem, T. Fried, D. Golodnitsky, L. Burstein, C.N.\nSukenik, G. Markovich, \"Alkyl Phosphonate/Phosphate Coating on\nMagnetite Nanoparticles: A Comparison with Fatty Acids,\" Langmuir,\nVol. 17, 2001, pp.7907-7911."]}

The influence of temperature on oscillations of the transverse magnetoresistance of ZnxCdyHg1−x−yTe (x = 0.08, y = 0.11) in the range 77 to 200 K and under magnetic fields of up to 2.5 T is studied. It is shown that the structure of the observed oscillations cannot be interpreted by participation of one kind of phonons only in magnetophonon resonance. The interpretation of experimental peaks with the help of magnetophonon resonances at different phonon frequencies describing the different sublattices of the solid solution (HgTe-like, CdTe-like, ZnTe-like) is given. [Russian Text Ignored].

The influence of addition of Zn on band parameters of ZnxCdyHg1-x-yTe solid solution at different temperatures (4.2-200 K) was investigated. The cyclotron resonance at 4.2 K and magnetophonon resonance at 77-200 K were used to determine band structure parameters. The temperature dependence of band structure parameters (energy gap, effective mass of electron) for the composition of series of epilayers (x varied in 0.08-0.20 range and y — 0.07-0.12) was obtained. It is found that band structure parameters for some compositions (for example x = 0.17, y = 0.08) are almost independent from temperature and equal: γL1= 19.55, γL2=38.5, KL = 6.48, F = -0.5, Eg = 0.35 eV, Ep = 17.9 eV. The effective mass of electrons was found to be greater with addition of Zn while the effective mass of heavy holes is left unchanged. PACS numbers: 71.25.Tn

In this experimental work a conception of the phonon spectra of the ${\text{Hg}}_{1\ensuremath{-}x}{\text{Cd}}_{x}\text{Te}(x=0.06--0.7)$ solid solution is presented which explains the presence of additional lines in the region $100--115\text{ }{\text{cm}}^{\ensuremath{-}1}$. Data of the optical reflectivity measurements obtained in far and middle infrared regions for eleven compositions of these alloys in the temperature range from 20 to 293 K using the synchrotron radiation ($\text{DA}\ensuremath{\Phi}\text{NE}$-LIGHT in LNF, Italy) as source are analyzed. Analyses were performed on samples of different types ($n$ and $p$ type) of conductivity as well as the temperature dependences of the line intensity under consideration in the region from 70 to $118\text{ }{\text{cm}}^{\ensuremath{-}1}$. The model of two valley potential of the mercury atom in the ${\text{Hg}}_{1\ensuremath{-}x}{\text{Cd}}_{x}\text{Te}$ lattice is used for interpretation of the additional phonon modes.

Similar ternary semiconductors are sometimes associated with widely different structures characterized by different site occupation preferences. We have used far-infrared (FIR) spectra to determine the site occupation preference coefficients for three ternary semiconductor alloys: ZnCdTe, ZnHgTe and CdHgTe and, in the case of ZnHgTe, have validated it by X-ray absorption fine structure (EXAFS) analysis. While ZnCdTe spectra exhibit the canonical configuration with eight phonon lines free of vibrational defect lines and only a slight departure from a random ion distribution, CdHgTe spectra show the eight canonical phonon modes plus an additional vibrational defect line and constant preference coefficients. In contrast, two defect lines and only four modes characterize ZnHgTe spectra, as extreme preferences prevent the formation of two of the five expected tetrahedral configuration arrangements. Moreover, for this system, comparison with EXAFS data points out the vibrational nature of both the extra lines. The analysis clearly shows that assuming a Bernoulli distribution of the component configurations of semiconductors may lead to wrong assessments of the evolution of its properties with relative content., JRC.D.5-Standards for Food Bioscience

The phonon spectrum of CdTe hydrogenated to various degrees is interpreted according to the original model, which takes into account the abundances of all naturally occurring Cd and Te stable isotopes and considers only five independent parameters to describe the 'bulk-isotope effect' line shape. The least square fitting (LSqF), unfolds the experimental data, obtained at different temperatures. The LSqF of the phonon line also considers the presence of additional oscillator contributions that we assign to vacancies or to lattice deformations occurring in the crystal.

We present a nondestructive method for quantitative determination of the vacancy concentration in the lattice of Hg-based semiconductor alloys with tetrahedral structure. The method is based on the identification of additional vibrational modes (AVMs) induced by lattice deformations in the far-infrared (FIR) reflectivity spectrum. Although the method is restricted by sensitivity limitations, recent FIR experimental data carried out on HgZnTe and HgCdTe samples containing Hg vacancies confirmed the presence of AVMs induced by Hg vacancies in as-grown crystals.

At the 2004 Ural International Winter School, we introduced the statistical strained tetrahedron model and discussed ternary tetrahedron structured crystals. The model allows one to interpret x-ray absorption fine structure (EXAFS) data and extract quantitative information on ion site occupation preferences and on the size and shape of each elemental constituent of the configuration tetrahedra. Here we extend the model to cover quaternary sphalerite crystal structures. We discuss the two topologically different quaternary sphalerite systems: the pseudo balanced A₁₋xBxYyZ₁₋y (2:2 cation:anion ratio), and the unbalanced AxBx C₁₋x₋x Z or AXyYy Z₁₋y₋y (3:1 or 1:3 cation:anion ratios) truly quaternary alloy systems. These structural differences cause preference values in pseudo quaternaries to vary with the relative contents, but to remain constant in truly quaternary compounds. We give equations to determine preference coefficient values from EXAFS or phonon spectra and to extract nearest-neighbour inter-ion distances by EXAFS spectroscopy. The procedure is illustrated and tested on CdMnSeTe, GaInAsSb, and ZnCdHgTe quaternary alloys.

The present work analyses the lattice deformations induced in the crystals with tetrahedral coordination by the presence of impurity hydrogen and oxygen atoms. Such deformations can be monitored by analyzing of far-infrared (FIR) vibration spectra. FIR experiments carried out on hydrogenated CdTe crystals that successfully revealed the presence and localization of hydrogen atoms within the lattice.

In this work, we present and discuss far-infrared (FIR) reflectivity spectra obtained using infrared synchrotron radiation in different Zn x Cd y Hg 1− x − y Te (ZMCT) quaternary alloys. Reflectivity spectra were measured at the DAFNE-light facility of the INFN-LNF with samples placed under vacuum inside a BRUKER Equinox 55 interferometer. Samples were cooled in a helium cryostat in a temperature range from about 20 K to 300 K. The obtained spectra were standard Kramers–Kronig transformed to obtain the imaginary part of the dielectric functions, then unfolded into a set of Lorentzian oscillators. The fitting procedure yields a total of 21 lines in the Zn x Cd y Hg 1− x − y Te reflection spectra of these quaternary alloys. Sixteen lines have been correlated to ternary spectral contributions of the different components: CdHgTe, ZnHgTe and CdZnTe (with a precision of ±1.5 cm −1 ). In the wave number range between 108 cm −1 and 190 cm −1 the oscillator frequencies have been attributed to the spectral lines of these quaternary alloys.

Infrared spectroscopy may deliver important information on defects created in CdTe monocrystals grown from Cd and Te components purified in a hydrogen atmosphere before the crystallization process. Reflectivity spectra on different CdTe samples were collected with a FTIR spectrometer using a standard Hg lamp and the IR synchrotron radiation source of the DAFNE synchrotron facility at Frascati. In the 500–2000 cm–1 frequency region, the characteristic vibrational spectra of oxygen and hydrogen bounded to Cd and Te in the monocrystalline CdTe were observed. Moreover the rich fine structure around the CdTe phonon frequency range has been resolved and the preliminary assignment of several lines has been performed. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

New opportunities in solid-state physics are offered by SINBAD (Synchrotron INfrared Beamline At DAFNE), the infrared beamline operational at DAΦNE, the storage ring of the Laboratori Nazionali di Frascati of the INFN. During 2003 several experiments, including those supported by the European TARI program, have been successfully performed at SINBAD. In this work we present the preliminary results of high resolution far infrared reflectivity data collected in different ZnxCdyHg(1–x–y)Te quaternary alloys as a function of temperature. The first far-IR investigation of Colossal Magnetoresistance manganites at high pressures, using a diamond anvil cell is also presented. Indeed, FT-IR spectroscopy is a powerful tool for the investigation of insulating-to-metal transitions and charge ordering phenomena that may occur in transition metal oxides. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

It is interesting to consider the problem of the presence of defects in the semiconductor binary compounds by observing their elemental tetrahedron distortions, caused by the creation of vacancies and interstitial atoms within the tetrahedra and so on. Our model thus considers the system A(Vz x Z) and (AVa y )Z as composed of five defect tetrahedron configurations where A is a cation atom, Z an anion atom, V a -cation vacancy, V z -anion vacancy. In this communication we present far IR (FIR) spectra obtained at the DAFNE facility of Laboratori Nazionali di Frascati (INFN) using its synchrotron radiation. Two samples of CdTe are considered: sample-1 was grown by the PVT technique and sample-2 using the same technique but on the basis of, polycrystalline CdTe previously purified from oxygen in hydrogen atmosphere.

Previous experiments have shown that extracts obtained from maturing male sex organs of Chara tomentosa, containing a low molecular weight peptide (termed antheridial chromatin condensation factor--ACCF) are capable to induce structural and functional effects in root meristems and fern gametophytes. Our present data point to a number of resemblances between the phenotypic characters of antheridial filaments (a.f.) and the properties of ACCF-treated human lymphocytes and HeLa cells; these comprise primarily a number of morphological changes at the nuclear/chromosomal levels. Mitotic chromosomes become shortened and the relative duration of prophase is reduced, while duration of telophase is prolonged. Nucleolar profiles in ACCF-treated HeLa cells become reduced. Significant decrease in mitotic activity was found in human and yeast cells (Schizosaccharomyces pombe). All the above similarities between the "innate" processes within a.f. and those induced by ACCF provide positive evidence for the presence of a highly specific factor that contributes to nuclear re-patterning of cells undergoing morphogenetic transformations before the onset of spermiogenesis.

The upper surface of tool steel has been enriched with SiC by the laser melting method. Before the laser treatment a layer of glass-water having a suspension of SiC powder was applied on the steel surface. Melting of the surface was done with the help of YAG Nd3+ pulsed laser. Metallographic and x-ray analyses have been done and their results are compared with changes of microhardness.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Four-component materials Zn x Cd y Hg 1-x-y T e have an important advantage. In a crystal lattice only the cationic part is changed: Hg, Cd and Zn while the anionic part remains unchanged. On the one hand this means that it is possible to obtain better quality crystals and epitaxial films; on the other hand it leads to the interesting phenomenon of the mixture of transverse and longitudinal optical oscillations of each mode:HgTe-like, CdTe-like and ZnTe-like.1,2 The energies of phonons have been presented in Table 1.