The crystal structure of bis(1H-pyrazole-carboxamidine-κN,N′)bis(nitrato-κO)-copper(II), C8H12CuN10O6

C8H12CuN10O6, triclinic, P 1 ‾ $P\overline{1}$ (no. 2), a = 7.6063(5) Å, b = 9.3072(7) Å, c = 10.8485(8) Å, α = 81.370(2)°, β = 75.503(2)°, γ = 84.756(2)°, V = 733.97(9) Å3, Z = 2, Rgt (F) = 0.0515, wRref (F 2) = 0.1194, T = 120(2) K.

Inorganic Salts of N-phenylbiguanidium(1+)-Novel Family with Promising Representatives for Nonlinear Optics

Seven inorganic salts containing N-phenylbiguanide as a prospective organic molecular carrier of nonlinear optical properties were prepared and studied within our research of novel hydrogen-bonded materials for nonlinear optics (NLO). All seven salts, namely N-phenylbiguanidium(1+) nitrate (C2/c), N-phenylbiguanidium(1+) perchlorate (P-1), N-phenylbiguanidium(1+) hydrogen carbonate (P21/c), bis(N-phenylbiguanidium(1+)) sulfate (C2), bis(N-phenylbiguanidium(1+)) hydrogen phosphate sesquihydrate (P-1), bis(N-phenylbiguanidium(1+)) phosphite (P21), and bis(N-phenylbiguanidium(1+)) phosphite dihydrate (P21/n), were characterised by X-ray diffraction (powder and single-crystal X-ray diffraction) and by vibrational spectroscopy (FTIR and Raman). Two salts with non-centrosymmetric crystal structures-bis(N-phenylbiguanidium(1+)) sulfate and bis(N-phenylbiguanidium(1+)) phosphite-were further studied to examine their linear and nonlinear optical properties using experimental and computational methods. As a highly SHG-efficient and phase-matchable material transparent down to 320 nm and thermally stable to 483 K, bis(N-phenylbiguanidium(1+)) sulfate is a promising novel candidate for NLO.

The red and blue luminescence in silicon nanocrystals with an oxidized, nitrogen-containing shell

Traditionally, two classes of silicon nanocrystals (SiNCs) are recognized with respect to their light-emission properties. These are usually referred to as the "red" and the "blue" emitting SiNCs, based on the spectral region in which the larger part of their luminescence is concentrated. The origin of the "blue" luminescence is still disputed and is very probably different in different systems. One of the important contributions to the discussion about the origin of the "blue" luminescence was the finding that the exposure of SiNCs to even trace amounts of nitrogen in the presence of oxygen induces the "blue" emission, even in originally "red"-emitting SiNCs. Here, we obtained a different result. We show that the treatment of "red" emitting, already oxidized SiNCs in a water-based environment containing air-related radicals including nitrogen-containing species as well as oxygen, diminishes, rather than induces the "blue" luminescence.

EOSINOPHILIC ANGIOCENTRIC FIBROSIS AS A CAUSE OF NASAL OBSTRUCTION. A CASE REPORT

Eosinophilic angiocentric fibrosis (EAF) is a rare benign lesion of unknown aetiology, found predominantly in the upper respiratory tract. The fibrosis must be confirmed by considering other lesions in the differential diagnosis. The typical histological characteristics are the basis for establishing the diagnosis. We present a patient with long-term nasal obstruction caused by EAF. The patient had repeated resections of the lesion for its recurrences. As follows from the literature, radical resection is crucial for the treatment of EAF. This procedure may be difficult at times given the extent and localization of the disease..

TRANSECTION OF INFERIOR ALVEOLAR NERVE IN THE RAT - NEUROANATOMICAL STUDY AND EXPERIMENTAL MODEL

OBJECTIVE

Experimental lesions in the inferior alveolar nerve (IAN) are used for the study of peripheral and central alterations. The objective of our study was to contribute to a more precise description of the approach to the IAN and creating a lesion.

MATERIAL AND METHODS

Twenty-six males of Wistar laboratory rats were used for the study. The animals were divided into three groups: control group (6 rats), experimental group (12 rats - a part of the bone above the mandibular canal was removed under general anaesthesia using extraoral approach, after exposing a part of the IAN, the nerve was excised in a length of 3 mm), and a sham group (8 rats - the nerve was only dissected but not transected). Persisting denervation was verified using surgical revision and histological and immunohistochemical analysis after the observation period (4 weeks).

RESULTS

No evidence of re-innervation after 4 weeks. We found no statistically significant differences in mean weight gains between individual groups during the observation period.

CONCLUSION

The described technique used in the study is one of the possible ways to create a nerve lesion at the site of the main trunk of the nerve. At the same time, the study provides a more precise description of the anatomical situation and approach to the IAN in the mandibular canal.

The crystal structure of 3-amino-(2,4-dioxopent-3-yl)-4,5-dihydro-1,2,4-triazinium nitrate, C8H13N5O5

C8H13N5O5, triclinic, P1̄ (no. 2), a = 9.1462(4) Å, b = 9.9732(5) Å, c = 13.5252(6) Å, α = 90.098(2)°, β = 91.031(2)°, γ = 109.874(2)°, V = 1160.02(9) Å3, Z = 4, R gt(F) = 0.0392, wR ref(F 2) = 0.1015, T = 150(2) K.

Intraosseous haemangioma od the zygoma - case report and literature review

Intraosseous haemangioma is a benign lesion that accounts for less than 1% of all bone tumours. It is found in the zygoma only rarely. This type of tumour is more common in women than in men. The paper presents the case of a female patient with intraosseous cavernous haemangioma in the zygoma. The tumour caused a deformation of the zygoma on the left. The lesion was visible in computed tomography (CT) scans, and also in magnetic resonance imaging (MRI) scans obtained previously due to problems unrelated to the lesion. We performed complete removal of the tumour including edges of healthy bone. The defect was bridge using a titanium miniplate. A good cosmetic effect was seen after 5 months from the surgery. Follow up CT and MRI evaluation showed no recurrence or residue of the tumour. The paper also includes a review of available literature.

Order-disorder phase transition in the peroxidovanadium complex NH4[VO(O2)2(NH3)]

Complex NH₄[VO(O₂)₂(NH₃)] (1) undergoes an order-disorder phase transition at T_c~258K. This transition is accompanied by change in the space group of the orthorhombic lattice and also by significant structural rearrangements of the constituent molecules, which are pertinent mostly to their NH₄⁺ ions and their ammonia ligands. The low-temperature solid state IR and Raman spectra of 1 were corroborated by solid-state computations that employed Gaussian functions as the basis set. Results of these computations yielded excellent agreement with experimental data. On the curves of temperature dependence of vibrational modes, the phase transition is expressed by an abrupt change of the slope above T_c.

Co-Crystals of 2-Amino-5-Nitropyridine Barbital with Extreme Birefringence and Large Second Harmonic Generation Effect

Technological innovation enforces a revolutionized approach towards materials chemistry. In this paper a new methodology towards crystal engineering of polar materials for possible applications in linear or non-linear optics (NLO), as well as ferroelectric, pyroelectric or piezoelectric crystals is presented. The necessity to fulfil several criteria concerning symmetry, electron properties of the building blocks, and also mechanical and optical stability was achieved by fusion of a pharmaceutical molecule and an NLO-phore. Co-crystals of 2-amino-5-nitropyridine barbital, presented in this manuscript, show cutting-edge optical performance. Large second harmonic generation (SHG) efficiency (40 times better than potassium dihydrogen phosphate, KDP), extreme birefringence (2.7 times higher than for calcite), simplicity in preparation, and optical and mechanical stability of the product proves that in fact a new generation of smart materials was obtained.

Multielemental Chemical Analysis of Elements in Mandibular Bone and Teeth in the Rat

The purpose of the study was to test the hypothesis of different distribution spaces of elements in the rat mandibular bone and teeth. We used six adult males of Wistar laboratory rats for the study. After killing the animals, we extracted the molars and removed incisor crowns. The mandibular bone was divided into four parts (mesial-central-distal-ridge). Inductively coupled plasma mass spectrometry was used to determine the presence of 41 elements in the bone and tooth. Evidence of 14 elements was found in all samples (incisors-molarsbone). Generally, significant differences between the left and right side were found for K and Rb in the bone locations. As regards statistically significant differences in incisors-molars-bone locations, the elements for which these differences were found for all comparisons are listed as incisors versus individual molars, incisors versus bone locations, and individual molars versus bone locations: a) incisors-molars: Ba, Mn, Mo, Sr, Zn, K, Mg and Rb; b) incisors-bone: Fe, K, Mg, Mn, Na, Zn and Ba; c) molars-bone: Mn, Mo, Na and Mg. Statistically significant differences were also found between molars for Fe, Mg, Mn, and Sr and between bone locations for Ba, Ca, Mn, Sr, K, Rb, Zn, Mo, Mg, and Na. The elements Cu, Ni and Co were without pronounced differences. Twenty-seven elements were below the detection limit. Our results indicate different distributions of some elements in the rat mandibular incisors-molars-bone. We assume that the knowledge of chemical element contents in the laboratory rat bone and teeth will prove useful in experimental research of both these hard tissues.

Multielemental Chemical Analysis of Elements in Mandibular Bone and Teeth in the Rat

The original article was published in Folia Biologica (Praha) Volume 64, No. 3 (2018), 84-96.

Migrating hydrogen in 2,4,6-triaminopyrimidinium(1+) x hydrogen trioxofluorophosphate(−) x monohydrate/2,4,6-triaminopyrimidinium(2+)1–x trioxofluorophosphate(2–)1–x monohydrate (0.0 < x < 0.73) with changing temperature

The data of the title structure of 2,4,6-triaminopyrimidinium(1+) x hydrogen trioxofluorophosphate(1−) x monohydrate/2,4,6-triaminopyrimidinium(2+)1−x trioxofluorophosphate(2−)1−x monohydrate (0.0 < x < 0.73), with the sum formula C4H11FN5O4P, were collected in 10 K intervals between 290 and 150 K, as well as at 100 K. The most interesting feature is the presence of a moderate though still strong O—H...N/O...H—N hydrogen bond. Its bridging H atom was found to be disordered over two positions in the temperature interval 290–220 K, with the larger occupation towards the O atom. The occupation in the latter position decreased with decreasing temperature, though not monotonously. At 210 K and below, the difference electron-density maps showed just one maximum which was closer to the N atom. Though difference scanning calorimetry (DSC) revealed no anomaly in the interval 303–93 K, the dependence of the length of the unit-cell axes b and c on temperature showed a kink in the slope at about 190 K. The N...O distance of the mentioned hydrogen bond or the occupational parameter of the electron density of the disordered H atom indicate less pronounced anomalies for the temperatures 270 and 230 K. The cation and the anion, as well as the water molecules, form layers which are parallel to (10\overline{1}) and which are interconnected by O—H...N (in the interval 290–220 K), N—H...O and O—H...O hydrogen bonds of moderate strength. The layers are arranged into centrosymmetric double layers in which the F atoms are directed outwards. The layers are interconnected by water–acid O—H...O hydrogen bonds, weak N—H...F interactions and π-electron ring...π-electron ring interactions. The dependence of P—F bond lengths on bonding properties of the trioxofluorophosphate or hydrogen trioxofluorophosphate anions is discussed. It has been recognized that a carbon-bonded F atom avoids participation in a hydrogen-bond pattern; however, this property seems to be also common to fluorine bonded to P, As and S, especially if an oxygen ligand is also present in a molecule. The deposited material contains an overview of the determined structures with trioxofluorophosphate or hydrogen trioxofluorophosphate anions.

Novel organic NLO material bis(N-phenylbiguanidium(1+)) oxalate - A combined X-ray diffraction, DSC and vibrational spectroscopic study of its unique polymorphism

Three polymorphic modifications of bis(N-phenylbiguanidium(1+)) oxalate are reported, and their characterization is discussed in this paper. The non-centrosymmetric bis(N-phenylbiguanidium(1+)) oxalate (I), which was obtained from an aqueous solution at 313K, belongs to the monoclinic space group Cc (a=6.2560(2)Å, b=18.6920(3)Å, c=18.2980(5)Å, β=96.249(1)°, V=2127.0(1)Å(3), Z=4, R=0.0314 for 4738 observed reflections). The centrosymmetric bis(N-phenylbiguanidium(1+)) oxalate (II) was obtained from an aqueous solution at 298K and belongs to the monoclinic space group P21/n (a=6.1335(3)Å, b=11.7862(6)Å, c=14.5962(8)Å, β=95.728(2)°, V=1049.90(9)Å(3), Z=4, R=0.0420 for 2396 observed reflections). The cooling of the centrosymmetric phase (II) leads to the formation of bis(N-phenylbiguanidium(1+)) oxalate (III) (a=6.1083(2)Å, b=11.3178(5)Å, c=14.9947(5)Å, β=93.151(2)°, V=1035.05(8)Å(3), Z=4, R=0.0345 for 2367 observed reflections and a temperature of 110K), which also belongs to the monoclinic space group P21/n. The crystal structures of the three characterized phases are generally based on layers of isolated N-phenylbiguanidium(1+) cations separated by oxalate anions and interconnected with them by several types of N-H(...)O hydrogen bonds. The observed phases generally differ not only in their crystal packing but also in the lengths and characteristics of their hydrogen bonds. The thermal behaviour of the prepared compounds was studied using the DSC method in the temperature range from 90K up to a temperature near the melting point of each crystal. The bis(N-phenylbiguanidium(1+)) oxalate (II) crystals exhibit weak reversible thermal effects on the DSC curve at 147K (heating run). Further investigation of this effect, which was assigned to the isostructural phase transformation, was performed using FTIR, Raman spectroscopy and X-ray diffraction analysis in a wide temperature range.

Crystal structures and vibrational spectra of biuret co-crystals with cyanuric and glutaric acids, discussion of hydrogen bonding involving carbonyl groups

The title structures of biuret-cyanuric acid (2/2) monohydrate, C10H18N12O11, 1 [P1̅, Z=2, a=8.2598(4) Å, b=10.8795(5) Å, c=11.9138(6) Å, α=67.036(1)°, β= 79.842(2)°, γ=69.859(2)°, V=924.38(8) Å3], and of biuret-glutaric acid (1/1), C7H13N3O6, 2 [P1̅, Z=2, a=5.0044(3) Å, b=7.0832(3) Å, c=14.9803(10) Å, α=102.860(4)°, β= 91.899(3)°, γ=102.202(4)°, V=504.20(5) Å3], show usual features both in constitution and intermolecular contacts except for a slightly longer C=O bond length in one of the carbonyl groups in 2. The biuret molecules have conformations with anti-parallel arrangement of the carbonyl groups. In each structure O–H…O and N–H…O hydrogen bonds of the moderate strength are present. The new results are compared with other structures which contain biuret molecules. The influence of the hydrogen bonding on the bond length of the carbonyl group C=O in the fragment NH2-(C=O)-NH with amine and hydroxyl donors has also been investigated. It transpires that the C=O…H angle of about 120° favors a slight elongation of the C=O bond length. The elongation of the C=O bond is more susceptible to the relative orientation of the C=O group with regard to amine over hydroxyl groups. This is the likely explanation why one of the C=O bonds in 2 is slightly longer than usual because this carbonyl group is simultaneously involved in two hydrogen bonds where C=O…H–O and C=O…H–N satisfy the 120° condition. Vibrational spectra of the title structures were also recorded and assigned.

The efficiency of micro-Raman spectroscopy in the analysis of complicated mixtures in modern paints: Munch's and Kupka's paintings under study

Twenty one mock-up samples containing inorganic pigments primarily used at the turn of the 19th and 20th century were selected for comparative study and measured by micro-Raman and portable Raman spectrometers. They included pure grounds (chalk-based, earth-based and lithopone-based), grounds covered by resin-based varnish, and different paint layers containing mixtures of white, yellow, orange, red, green, blue and black pigments, usually in combination with white pigments (titanium, zinc and barium whites or chalk). In addition, ten micro-samples obtained from seven paintings of two world-famous modern painters Edvard Munch and František Kupka have been investigated. Infrared reflection spectroscopy (FTIR), portable X-ray fluorescence (XRF) and scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) were used as supplementary methods. The measurements showed that blue pigments (ultramarine, Prussian blue and azurite), vermilion and ivory black in mixture with whites provided characteristic Raman spectra, while Co-, Cd- and Cr- pigments' bands were suppressed by fluorescence. The best success rate of micro-Raman spectroscopy has been achieved using the 780 nm excitation, however, the sensitivity of this excitation laser in a portable Raman instrument significantly decreased. The analyses of micro-samples of paintings by E. Munch and F. Kupka showed that micro-Raman spectroscopy identified pigments which would remain unidentified if analyzed only by SEM-EDS (zinc yellow, Prussian blue). On the other hand, chromium oxide green and ultramarine were not detected together in a sample due to overlap of their main bands. In those cases, it is always necessary to complement Raman analysis with other analytical methods.

USE OF OSTEOTOMY IN POST-TRAUMATIC DEFORMITY OF FRONTAL SINUS ANTERIOR WALL. CASE REPORT

Post-traumatic deformity of frontal sinus anterior table can be treated in various ways. Usage of a certain type of an implant is a common method. We performed an osteotomy and subsequent reduction of the fragments to reconstruct their anatomical position. Titanium miniplates and screws were used for fixation. This case report suggests a possible use of this method in patients with more extensive frontal sinus and distinct post-traumatic deformity. No similar case manages as described in our case report was found in the literature.

UPPER EYELID INJURY WITH PARTIAL LOSS. CASE REPORT

In case of an upper eyelid injury with loss of tissue, it is very important to perform reconstruction to restore protection of the cornea and bulbus. Depending on the size and location of the defect the most suitable reconstructive technique is chosen. This case report presents a patient with a partial loss of the upper eyelid. The defect was reconstructed with a transposition skin flap to cover the ear cartilage graft. The missing conjunctiva was partially reconstructed by its mobilization from the fornix, and a part of the defect was left to heal by spontaneous epithelisation. This procedure provides an alternative solution for defects in the lateral part of the upper eyelid.

Single crystals of guanidinium zinc sulfate, [C(NH2)3]2Zn(SO4)2 – growth, structure, vibrational spectroscopy and stimulated Raman scattering

Large single crystals of the tetragonal (space group I4̅2d) guanidinium zinc sulfate, [C(NH2)3]2Zn(SO4)2, were grown and the crystal structure was redetermined. Vibrational spectra obtained by Raman and IR investigations are presented, together with an assignment of the observed vibration modes. Precise refractive index data in the wavelength range from 0.365 to 1.083 μm are given. [C(NH2)3]2Zn(SO4)2 is introduced as a new stimulated Raman scattering (SRS)-active crystal with three SRS-active vibration modes with ω SRS1 ≈ 985 cm–1, ω SRS2 ≈ 3390 cm–1 and ω SRS3 ≈ 1015 cm–1. They allow for the generation of broadband nonlinear emission via χ (3)- (SRS and Raman-induced four wave mixing, RFWM) as well as cascaded χ (2)↔χ (3)- processes.

Raman spectroscopic study of the Chromobacterium violaceum pigment violacein using multiwavelength excitation and DFT calculations

Violacein is a bisindole pigment occurring as a biosynthetic product of Chromobacterium violaceum and Janthinobacterium lividum. It has some structural similarities to the cyanobacterial UV-protective pigment scytonemin, which has been the subject of comprehensive spectroscopic and structural studies. A detailed experimental Raman spectroscopic study with visible and near-infrared excitation of violacein produced by C. violaceum has been undertaken and supported using theoretical DFT calculations. Raman spectra with 514 and 785 nm excitation of cultivated cells as well as extracts and Gaussian (B3LYP/6-311++G(d,p)) calculations with proposed molecular vibrational assignments are reported here.

Twisted intramolecular charge transfer and its contribution to the NLO activity of Diglycine Picrate: a vibrational spectroscopic study

Single crystals of Diglycine Picrate (DGLP) were grown by slow evaporation technique and the vibrational spectral analysis is carried out using FT Raman and FT-IR spectroscopy, supported by Density Functional Theoretical (DFT) computations to derive equilibrium geometry, vibrational wavenumbers and first hyperpolarizability. The vibrational spectra confirm the existence of NH3(+) in DGLP. The influence of Twisted Intramolecular Charge Transfer (TICT) caused by the strong ionic ground state hydrogen bonding between charged species making DGLP crystal to have the non-centrosymmetric structure has been discussed. The Natural Bond Orbital (NBO) analysis confirms the occurrence of strong intermolecular N-H⋯O hydrogen bond. The HOMO-LUMO energy gap and the first order hyperpolarizability were calculated and it supports the nonlinear optical activity of the Diglycine Picrate crystal.

Potential and limits of Raman spectroscopy for carotenoid detection in microorganisms: implications for astrobiology

In this paper, it is demonstrated how Raman spectroscopy can be used to detect different carotenoids as possible biomarkers in various groups of microorganisms. The question which arose from previous studies concerns the level of unambiguity of discriminating carotenoids using common Raman microspectrometers. A series of laboratory-grown microorganisms of different taxonomic affiliation was investigated, such as halophilic heterotrophic bacteria, cyanobacteria, the anoxygenic phototrophs, the non-halophilic heterotrophs as well as eukaryotes (Ochrophyta, Rhodophyta and Chlorophyta). The data presented show that Raman spectroscopy is a suitable tool to assess the presence of carotenoids of these organisms in cultures. Comparison is made with the high-performance liquid chromatography approach of analysing pigments in extracts. Direct measurements on cultures provide fast and reliable identification of the pigments. Some of the carotenoids studied are proposed as tracers for halophiles, in contrast with others which can be considered as biomarkers of other genera. The limits of application of Raman spectroscopy are discussed for a few cases where the current Raman spectroscopic approach does not allow discriminating structurally very similar carotenoids. The database reported can be used for applications in geobiology and exobiology for the detection of pigment signals in natural settings.

Comparison of the hydrogen-bond patterns in 2-amino-1,3,4-thiadiazolium hydrogen oxalate, 2-amino-1,3,4-thiadiazole-succinic acid (1/2), 2-amino-1,3,4-thiadiazole-glutaric acid (1/1) and 2-amino-1,3,4-thiadiazole-adipic acid (1/1)

The X-ray single-crystal structure determinations of the chemically related compounds 2-amino-1,3,4-thiadiazolium hydrogen oxalate, C2H4N3S(+)·C2HO4(-), (I), 2-amino-1,3,4-thiadiazole-succinic acid (1/2), C2H3N3S·2C4H6O4, (II), 2-amino-1,3,4-thiadiazole-glutaric acid (1/1), C2H3N3S·C5H8O4, (III), and 2-amino-1,3,4-thiadiazole-adipic acid (1/1), C2H3N3S·C6H10O4, (IV), are reported and their hydrogen-bonding patterns are compared. The hydrogen bonds are of the types N-H···O or O-H···N and are of moderate strength. In some cases, weak C-H···O interactions are also present. Compound (II) differs from the others not only in the molar ratio of base and acid (1:2), but also in its hydrogen-bonding pattern, which is based on chain motifs. In (I), (III) and (IV), the most prominent feature is the presence of an R2(2)(8) graph-set motif formed by N-H···O and O-H···N hydrogen bonds, which are present in all structures except for (I), where only a pair of N-H···O hydrogen bonds is present, in agreement with the greater acidity of oxalic acid. There are nonbonding S···O interactions present in all four structures. The difference electron-density maps show a lack of electron density about the S atom along the S···O vector. In all four structures, the carboxylic acid H atoms are present in a rare configuration with a C-C-O-H torsion angle of ∼0°. In the structures of (II)-(IV), the C-C-O-H torsion angle of the second carboxylic acid group has the more common value of ∼|180|°. The dicarboxylic acid molecules are situated on crystallographic inversion centres in (II). The Raman and IR spectra of the title compounds are presented and analysed.

Structural conformations and density functional study on the intramolecular charge transfer based on vibrational spectra of 2,4-dihydroxy-N'-(4-methoxybenzylidene)benzohydrazide

The NIR-FT Raman and FT-IR spectra of 2,4-dihydroxy-N'-(methoxybenzylidene) benzohydrazide (DMBBH) molecule have been recorded and analyzed. Density functional theory (DFT) calculations at the B3LYP/6-31G(d) level has been used to compute energies of different conformers of DMBBH to find out their stability, the optimized geometry of the most stable conformer and its vibrational spectrum. Information about the size, shape, charge density distribution and site of chemical reactivity of the molecules has been obtained by mapping electron density isosurface with electrostatic potential surfaces (ESP). A complete vibrational analysis has been attempted on the basis of experimental infrared and Raman spectra and calculated vibrational modes and potential energy distribution over the internal coordinates. The vibrational analysis confirm the charge transfer interaction between the phenyl rings through C=N-N skeleton. The broadening of the band at 1631 cm(-1) and the appearance of the band at 1556 cm(-1) strongly suggests the existence of proton equilibrium.

Ultrafast optical nonlinearity, electronic absorption, vibrational spectra and solvent effect studies of ninhydrin

FT-IR, FT-Raman and UV-Vis spectra of the nonlinear optical molecule ninhydrin have been recorded and analyzed. The equilibrium geometry, bonding features, and harmonic vibrational wavenumbers have been investigated with the help of B3LYP density functional theory method. A detailed interpretation of the vibrational spectra is carried out with the aid of normal coordinate analysis following the scaled quantum mechanical force field methodology. Solvent effects have been calculated using time-dependent density functional theory in combination with the polarized continuum model. Natural bond orbital analysis confirms the occurrence of strong intermolecular hydrogen bonding in the molecule. Employing the open-aperture z-scan technique, nonlinear optical absorption of the sample has been studied in the ultrafast and short-pulse excitation regimes, using 100 fs and 5 ns laser pulses respectively. It is found that ninhydrin exhibits optical limiting for both excitations, indicating potential photonic applications.

Reconstruction of a nasal tip defect using a V-Y island dorsal nasal flap with unilateral vascular supply. A case report

Closure of a nasal tip defect has specific characteristics with regards to the shape, colour, thickness and texture of skin. During the reconstruction it is necessary to observe aesthetic and functional characteristics to achieve an optimal result. There are several methods for closure of a defect in this area. One of the possible techniques is usage of a local flap. In the selection of an optimal procedure it is suitable to consider the aesthetic subunits in the nose. Usage of the V-Y flap is beneficial compared to a rotation flap or a transposition flap, which are associated with significant scaring and deformities, such as a dog-ear. Such conditions may require further corrections later. Erçöçen et al. described a V-Y island dorsal nasal flap, which they used to close a nasal tip defect. The blood supply of the flap was based on the terminal branches of angular artery on both sides (1). In our case report we used the aforementioned flap to close a nasal defect. The flap was based on the terminal branches of the angular artery only on one side.

1,1-Dimethyl-biguanidium(2+) dinitrate

In the crystal structure of the title compound, C(4)H(13)N(5) (2+)·2NO(3) (-), the main inter-molecular inter-actions are the N-H⋯O hydrogen bonds between the cationic amino groups and the O atoms of the nitrate ions. All amino H atoms and nitrate O atoms are involved in the three-dimensional hydrogen-bond network. There are two graph-set motifs R(2) (2)(8), which include the amino groups connected to the N atoms in the biguanide 3-, 4- and 5-positions, and the O atoms of a nitrate ion. They are extended along the a axis. An O atom of the second nitrate ion is involved in a graph-set motif C(4) that is a part of a helix-like N-H⋯O⋯H-N-H⋯O⋯ chain oriented along the b axis. There are also two weak C-H⋯O inter-actions in the crystal structure.

Tris(2-amino-1,3-thia-zolium) hydrogen sulfate sulfate monohydrate

The centrosymmetric crystal structure of the novel semi-organic compound, 3C₃H₅N₂S⁺·HSO₄⁻·SO₄²⁻·H₂O, is based on chains of alternating anions and water mol­ecules (formed by O—H⋯O hydrogen bonds). The chains are inter­connected with the 2-amino-1,3-thia­zolium cations via strong N—H⋯O and weak C—H⋯O hydrogen-bonding inter­actions into a three-dimensional network.

2-Amino-1,3-thia-zolium dihydrogen phosphate

In the title compound, C(3)H(5)N(2)S(+)·H(2)PO(4) (-), the dihydrogen phosphate anions form infinite chains along [001] via short O-H⋯O hydrogen bonds. The 2-amino-thia-zolium cations inter-connect these chains into a three-dimensional network by short linear or bifurcated N-H⋯O and weak C-H⋯O hydrogen bonds.

Bis(2-phenyl-biguanidium) adipate tetra-hydrate

In the title salt, 2C(8)H(12)N(5) (+)·C(6)H(8)O(4) (2-)·4H(2)O, the anion is located on a centre of symmetry. The observed supra-molecular network of the crystal structure is produced by ten different hydrogen bonds of the N-H⋯N, N-H⋯O and O-H⋯O types. One additional O-H group is not connected to an acceptor site.

4-Amino-1H-1,2,4-triazol-1-ium nitrate

The non-centrosymmetric crystal structure of the novel semi-organic title compound, C(2)H(5)N(4) (+)·NO(3) (-), is based on alternating layers of 4-amino-1H-1,2,4-triazolinium cations (formed by parallel chains of cations mediated by weak C-H⋯N hydrogen bonds) and nitrate anions inter-connected via linear and bifurcated N-H⋯O hydrogen bonds and weak C-H⋯O hydrogen bonds. N-H⋯N hydrogen bonds link the anions and cations.

Systematic study of Mn-doping trends in optical properties of (Ga,Mn)As

We report on a systematic study of optical properties of (Ga,Mn)As epilayers spanning the wide range of accessible Mn(Ga) dopings. The material synthesis was optimized for each nominal Mn doping in order to obtain films which are as close as possible to uniform uncompensated (Ga,Mn)As mixed crystals. We observe a broad maximum in the mid-infrared absorption spectra whose position exhibits a prevailing blueshift for increasing Mn doping. In the visible range, a peak in the magnetic circular dichroism also shifts with increasing Mn doping. The results are consistent with the description of ferromagnetic (Ga,Mn)As based on the microscopic valence band theory. They also imply that opposite trends seen previously in the optical data on a limited number of samples are not generic and cannot serve as an experimental basis for postulating the impurity band model of ferromagnetic (Ga,Mn)As.

2-Phenyl-biguanidinium hydrogen succinate methanol monosolvate

In the crystal of the title compound, C₈H₁₂N₅⁺·C₄H₅O₄⁻·CH₃OH, the hydrogen succinate anions form infinite [010] chains via short, almost symmetrical, O⋯H⋯O hydrogen bonds. The 2-phenyl­biguanidium cations inter­connect these chains into layers lying parallel to the bc plane by way of N—H⋯O links. These planes only weakly inter­act in the direction of the a axis via C—H⋯π contacts between offset phenyl rings, leaving as much as 17% of the unit-cell volume accessible for the solvent. However, the methanol solvent mol­ecules could not be resolved due to extensive disorder and their assumed presence was removed from the overall scattering by the PLATON SQUEEZE procedure.