Inhibition of urinary calculi—a spectroscopic study

Although herbal medicine is widely employed in inhibition of urinary calculi as an alternative and complementary curative method, the lack of detailed scientific studies that could provide insights into this complex process weakens its validity. The present work targets multitechnique spectroscopic investigations by Raman, infrared absorption, X‐ray photoelectron spectroscopy (XPS), and photoluminescence on the effects of the herb Rotula Aquatica Lour (RAL) on the growth of synthetically prepared magnesium‐based calculi. In addition to the standard magnesium phosphate‐based sample, two other samples were prepared with incorporation of 1 and 2wt% RAL herbal extract. Both, Raman and infrared data show a newberyite structure for the crystals without and with inhibitor. The XPS measurements reveal an unexpected presence of Zn in the sample with bfRAL inhibitor, which, as suggested in the literature, may initiate rapid stone formation, and consequently, contribute to the inhibition process. Furthermore, the existence of metallic Zn can explain the reflectance of the incident light observed in the infrared transmission studies of the unground crystals. A significant increase in magnesium with addition of herbal extract is observed in the XPS data. Also, evidence for Mg O binding between the inhibitor and the phosphate units of urinary calculus is found in XPS and Raman results. Similarity between our photoluminescence measurements and those of in vivo chlorophyll a corroborates to provide additional evidence of Mg‐related inhibition. Copyright © 2009 John Wiley & Sons, Ltd.     

红外光谱法在草酸钙结石研究中的应用

泌尿系结石是一种世界范围的常见病。草酸钙是泌尿系结石中最常见的组分 ,尿石中的草酸钙主要是以一水草酸钙 (COM)、二水草酸钙 (COD)的形式存在。区分草酸钙结石中的COM和COD及其比例 ,对于准确诊断结石的成因和提出正确的预防其复发的方法非常重要。红外光谱法是研究泌尿系结石的一种较理想的常用方法 ,具有快速、简便、鉴定成分准确、使用样品少、可以回收等优点。文中重点综述了傅里叶变换红外光谱 (FTIR)在泌尿系结石研究中对COM和COD的定性和定量分析方法 ,并介绍了零交叉点一次导数光谱法、FTIR与四极质谱仪、FTIR与傅里叶变换拉曼光谱仪 (FTRS)联合分析尿石的方法。     

不同类型尿石的XRD,FTIR和热释光谱分析

采用热释光谱仪(TLD)、X射线衍射仪(XRD)和红外光谱仪(FTIR)研究了四类不同类型肾结石的化学组分,它们分别是:草酸钙、尿酸、磷酸钙和磷酸铵镁结石.实验结果表明,在所研究的305例尿石中,草酸钙为主要组分的占63%,尿酸22%,磷酸钙8%,磷酸铵镁5%,其他组分2%.四类肾结石的热释光谱存在显著差异,可为临床上诊断肾结石的类型提供启示.     

草酸钙结石患者尿液中纳米级和微米级晶体研究

尿液中存在的微晶与尿石症的形成密切相关。采用X射线粉末衍射(XRD)、傅里叶变换红外光谱(FTIR)、纳米粒度仪、扫描电子显微镜(SEM)和透射电子显微镜(TEM)研究了20位草酸钙结石患者尿液中纳米级和微米级晶体的组分、形貌和Zeta电位,并与结石组分进行了比较。结果表明,草酸钙结石中常常含有少量共生的尿酸、磷酸钙和磷酸铵镁;而草酸钙结石患者的尿微晶组分主要为尿酸、磷酸盐和草酸钙等,晶体棱角尖锐,尺寸不一,从几十纳米到几十微米不等,并且有明显的团聚现象。20位草酸钙结石患者的尿纳米晶体的Zeta电位平均值为-5.92 mV,明显高于20位健康对照者尿纳米晶体的Zeta电位(平均值-12.9 mV);相比之下,结石患者尿液pH值(平均值为6.03)则与健康对照者(平均值5.92)没有明显差异。利用现代仪器分析方法分析尿液微晶与尿石组分的关系,可为临床上对症下药,制定预防与治疗措施提供重要的依据。     

An ab initio study of the vibrational properties of alkaline-earth metal nitrates and their crystallohydrates

The vibrational frequencies and corresponding intensities have been calculated ab initio for the center of the Brillouin zone of crystalline magnesium, calcium, strontium, and barium nitrates; magnesium nitrate hexahydrate; and calcium nitrate tetrahydrate. The calculation has been performed within the electron- density functional theory using the PBE exchange-correlation functional in the basis of localized atomic orbitals with the aid of the CRYSTAL14 software. The calculated values and the experimental IR and Raman spectral data on strontium and barium nitrates are shown to be in satisfactory agreement. The frequencies of normal long-wavelength vibrations in the nitrates become red-shifted with an increase in the cation atomic mass. The occurrence of several peaks due to the vibrations of hydrogen atoms in water molecules with different dynamic charges is predicted in the IR spectrum of hexahydrate magnesium in the frequency range above 3430 cm^–1.     

Quantitative and multicomponent analysis of prevalent urinary calculi using Raman spectroscopy

This study established a quantitative micro‐Raman spectroscopic (MRS) method for measuring multicomponents (binary and ternary compositions) of prevalent urine calculi extracted from the ureter after the ureteroscopic lithotripsy (URSL) procedure. The analysis used calibration curves of known mixtures of synthetically prepared calcium oxalate monohydrate (COM), hydroxyapatite (HAP), calcium oxalate dehydrate (COD), dicalcium phosphate dehydrate (DCPD), and uric acid. A variety of samples of binary and ternary mixtures including COM/HAP, COM/COD, COD/HAP, COM/uric acid, COD/uric acid, HAP/uric acid, HAP/DCPD, and COM/COD/HAP were prepared in various concentration ratios for use as the basis of the quantitative analysis. Intensities of the characteristic bands at 961 cm⁻¹ (I_HAP), 986 cm⁻¹ (I_DCPD), 1402 cm⁻¹ (I_UricAcid), 1462 cm⁻¹ (I_COM), and 1477 cm⁻¹ (I_COD) were used for the calculation. We derived a set of quantitative analysis equations for the ternary composition COD/COM/HAP group by combining two binary equations from the groups COM/COD and the HAP/COM. This study quantitatively measured 18 urine samples extracted from the 18 patients' ureters after the URSL procedure. Fifteen samples were binary mixtures, whereas three samples were ternary mixtures. This research successfully applied the quantitative MRS‐based analysis technique from bench to bedside. Copyright © 2012 John Wiley & Sons, Ltd.     

三聚氰胺结石与疑似三聚氰胺结石的红外光谱分析

本文通过对三聚氰胺、尿酸、三聚氰胺结石和疑似三聚氰胺结石的红外光谱分析, 根据它们的特征峰位、峰形的特点和三聚氰胺、尿酸、草酸钙的标准红外光谱比较, 推出三聚氰胺结石由尿酸、尿酸胺、草酸钙和三聚氰胺形成的混合性结石。疑似三聚氰胺结石是草酸钙结石。因此, 红外光谱法可作为一种辅助手段, 为医学诊断提供理论依据。     

Involvement of weak C?H···X hydrogen bonds in metal‐to‐semiconductor regime change in one‐dimensional organic conductors (o‐DMTTF)2X (X = Cl,Br, and I): combined IR and Raman studies

We report on the infrared (IR) and Raman studies of the three isostructural quasi‐one‐dimensional cation radical salts of 3,4‐dimethyl‐tetrathiafulvalene (o‐DMTTF)₂X (X = Cl, Br, and I), which all exhibit metallic properties at room temperature and undergo transitions to a semiconducting state in two steps: a soft metal‐to‐semiconductor regime change in the temperature region T_ρ = 5–200 K and then a sharp phase transition at about T_MI = 50 K. Polarized IR reflectance spectra (700–16 000 cm⁻¹) and Raman spectra (50–3500 cm⁻¹, excitation λ = 632.8 nm) of single crystals were measured as a function of temperature (T = 5–300 K) to assess the eventual formation of a charge‐ordered state below 50 K. Additionally, the temperature dependence of the IR absorption spectra of powdered crystals in KBr discs was also studied. The Raman spectra and especially the bands related to the CC stretching vibration of o‐DMTTF provide unambiguous evidence of uniform charge distribution on o‐DMTTF down to the lowest temperatures, without any modification below 50 K. However, the temperature dependence of Raman spectra indicates a regime change below about 200 K. Temperature dependence of both electronic dispersion and vibrational features observed in the IR spectra also clearly confirms the regime change below about 200 K and shows the involvement of C H···X hydrogen bonds in the electronic localization; some spectral changes can be also related with the phase transition at 50 K. Additionally, using density functional theory methods, the normal vibrational modes of the neutral o‐DMTTF⁰ and cationic o‐DMTTF⁺ species, as well as their theoretical IR and Raman spectra, were calculated. The theoretical data were compared with the experimental IR and Raman spectra of neutral o‐DMTTF molecule. Copyright © 2011 John Wiley & Sons, Ltd.     

Vibrational spectroscopy and crystal structure analysis of two polymorphs of the di‐amino acid peptide cyclo(L‐Glu‐L‐Glu)

Cyclo(L ‐Glu‐L ‐Glu) has been crystallised in two different polymorphic forms. Both polymorphs are monoclinic, but form 1 is in space group P2₁ and form 2 is in space group C2. Raman scattering and FT‐IR spectroscopic studies have been conducted for the N,O‐protonated and deuterated derivatives. Raman spectra of orientated single crystals, solid‐state and aqueous solution samples have also been recorded. The different hydrogen‐bonding patterns for the two polymorphs have the greatest effect on vibrational modes with N H and CO stretching character. DFT (B3‐LYP/cc‐pVDZ) calculations of the isolated cyclo(L ‐Glu‐L ‐Glu) molecule predict that the minimum energy structure, assuming C₂ symmetry, has a boat conformation for the diketopiperazine ring with the two L ‐Glu side chains being folded above the ring. The calculated geometry is in good agreement with the X‐ray crystallographic structures for both polymorphs. Normal coordinate analysis has facilitated the band assignments for the experimental vibrational spectra. Copyright © 2009 John Wiley & Sons, Ltd.     

Vibrational spectra and crystal structure of the di‐amino acid peptide cyclo(L‐Met‐L‐Met): comparison of experimental data and DFT calculations

Experimental Raman and FT‐IR spectra of solid‐state non‐deuterated and N‐deuterated samples of cyclo(L ‐Met‐L ‐Met) are reported and discussed. The Raman and FT‐IR results show characteristic amide I vibrations (Raman: 1649 cm⁻¹, infrared: 1675 cm⁻¹) for molecules exhibiting a cis amide conformation. A Raman band, assigned to the cis amide II vibrational mode, is observed at ∼1493 cm⁻¹ but no IR band is observed in this region. Cyclo(L ‐Met‐L ‐Met) crystallises in the triclinic space group P1 with one molecule per unit cell. The overall shape of the diketopiperazine (DKP) ring displays a (slightly distorted) boat conformation. The crystal packing employs two strong hydrogen bonds, which traverse the entire crystal via translational repeats. B3‐LYP/cc‐pVDZ calculations of the structure of the molecule predict a boat conformation for the DKP ring, in agreement with the experimentally determined X‐ray structure. Copyright © 2009 John Wiley & Sons, Ltd.     

The pH effects on the growth rate of KDP (KH2PO4) crystal by investigating Raman active lattice modes

We report on the dependence of the pH value on the growth rates of KDP single crystals. Extensive experimental work has been carried out in order to find the optimum pH ranges for growing KDP single crystals with suitable sizes and high optical quality. Different techniques including micro‐Raman back‐scattering spectroscopy, UV/vis/IR transmission spectroscopy and X‐ray diffraction have been employed for this investigation. Deuterated substituted single crystals of KDP and DKDP also have been grown for the investigation of growth rates and Raman active mode identification purposes. The molecular vibration modes of the grown crystals, including internal modes of PO₄ tetrahedrons molecular vibrations, external modes of optical phonons and hydrogen bonding modes have been determined exactly by micro‐Raman back‐scattering spectroscopy. The best pH values of the solution for the KDP crystal growth with reasonably higher growth rates from aqueous solutions that have been supersaturated ata temperature range of 30–50 °C have been found to be in the pH range of 3.2–5.4. Copyright © 2007 John Wiley & Sons, Ltd.     

Infrared and Raman spectroscopic studies of the charge localization in one‐dimensional organic metals (DMtTTF)2X (X = ReO4, ClO4) with regular organic stacks

A novel selective synthesis of the unsymmetrically substituted tetrathiafulvalene dimethyltrimethylene‐tetrathiafulvalene (DMtTTF) is described together with its electrocrystallization to the known conducting mixed‐valence ClO₄^– and ReO₄^– salts. Infrared (IR) and Raman spectra of the two isostructural quasi‐one‐dimensional cation radical salts (DMtTTF)₂X (X = ReO₄^–, ClO₄^–) are investigated as a function of temperature (T = 5–300 K). At ambient temperature, these salts show metallic‐like properties and below T_ρ = 100–150 K, they undergo a smeared transition to semiconducting state. To study this charge localization, we measured temperature dependence of polarized IR reflectance spectra (700–16 000 cm^–1) and Raman spectra (150–3500 cm^–1, excitation λ = 632.8 nm) of single crystals. For both compounds, the Raman data and especially the bands related to the C=C stretching vibration of the DMtTTF molecule show that the charge distribution on molecules is uniform down to the lowest temperatures. Similarly, IR data confirm that down to the lowest temperatures, there is neither charge ordering nor important modification of the electronic structure. However, the temperature dependence of Raman spectra of both salts reveals a regime change at about 150 K. Additionally, using Density Functional Theory (DFT) methods, the normal vibrational modes of the neutral DMtTTF⁰ and cationic DMtTTF⁺ species and also their theoretical IR and Raman spectra were calculated. The theoretical data were compared with the experimental IR and Raman spectra of neutral DMtTTF⁰ molecule. Copyright © 2013 John Wiley & Sons, Ltd.     

几种饱和脂肪酸及其盐的拉曼光谱研究

饱和脂肪酸及其盐在自然界中广泛存在,它们也是重要的化工原料。但是有关此类物质拉曼光谱特征的研究尚属少见。为了进一步了解它们的拉曼光谱特征,对乙酸、硬脂酸及乙酸钙、乙酸镁、硬脂酸钙、硬脂酸镁进行了拉曼光谱研究。从指认这6种物质拉曼光谱的特征峰拉曼位移出发,对它们的相应谱峰进行比对与分析,探讨了阳离子的引入对饱和脂肪酸及其盐的拉曼光谱的影响,找出了它们拉曼光谱的差异。比较不同阳离子形成的饱和脂肪酸盐的特征峰拉曼位移的差别,从折合质量和核外电子构型角度解释了造成差异的原因。同时发现了长碳链可以减弱不同阳离子对饱和脂肪酸盐拉曼光谱造成的影响。     

泽泻抑制尿草酸钙结石形成活性成分的 2D NMR分析

从中药泽泻[Alisma orientalis (Sam.)Juzep.]抑制尿草酸钙结石形成的活性部位分离得到3个化合物, 并鉴定为alisol F 24-acetate、alisol A 24-acetate和alismoxide. 首次应用¹H-¹H COSY、HMQC和HMBC 等2D NMR技术对alisol F 24-acetate的氢信号进行全归属.     

Vibrational and optical properties of a one‐dimensional organic–inorganic crystal [C6H14N]PbI3

Self‐assembled organic–inorganic [C₆H₁₄N]PbI₃ crystals were synthesized. The crystal structure consists of one‐dimensional semiconductor chains formed by infinite PbI₆ face‐sharing octahedra aligned along the a‐axis. The organic cations are linked to the inorganic chains by N H· · ·I hydrogen bonds and act as insulator barriers. The vibrational properties of [C₆H₁₄N]PbI₃ were studied using polarized Raman scattering and infrared (IR) absorption. The observed Raman and IR spectral features were identified by comparison with the vibrational properties of homologous compounds and with the vibrational wavenumbers calculated using the ab initio PM3 method. Moreover, the photoluminescence and diffuse reflectance of [C₆H₁₄N]PbI₃ single crystals, along with the UV‐Vis absorption of spin‐ coated films, were measured. A strong green‐blue luminescence due to radiative recombinations of 1D excitons is observed. The Stokes shift is estimated at 70 meV. Copyright © 2008 John Wiley & Sons, Ltd.     

Raman spectroscopy study of compositional inhomogeneity in lithium tantalate crystals

Raman spectra of LiTaO₃ single crystals with various stoichiometries were measured to investigate the compositional uniformity of these crystals. Raman spectra mapping demonstrates a spatial variation of the widths of the phonon bands for stoichiometric, congruent, and quasi-congruent samples. A significant radial compositional inhomogeneity is found to be a common feature of commercially available wafers having a near-congruent crystal composition (i.e., x _c ={[Li₂O]/([Li₂O]+[Ta₂O₅])}×100%=47.85–48.50%) grown by the single-crucible Czochralski method. A maximum value of the composition gradient ∇ x _c for a radial inhomogeneity of 0.163 and 0.036%/cm is measured for thin wafers diced from so-called congruent (vendors’ value of x _c =48.50%) and quasi-congruent (x _c =47.88%) crystals, respectively. In crystals grown from highly Li-rich melts (starting composition 54.5 mol% Li₂O), a drastic spatial dependence of Raman bandwidths, indicating a significant gradual compositional inhomogeneity throughout the crystal, is found, which is due to a change of the melt composition during crystal growth. In contrast, the Raman bandwidths of near-stoichiometric crystals fabricated by a vapor transport equilibrium (VTE) technique are found to be constant, i.e. these crystals are practically compositionally uniform. This conclusion has been confirmed by mapping the photoluminescence intensity, evidencing ∇ x _c ≤0.006%/cm in near-stoichiometric VTE-treated crystals.     

Far infrared and phase transitions in ferroelectric materials

Abstract

A number of far infrared absorption bands are found in molecular and hydrogen-bonded crystals when there are several formula units in the primitive cell. They are very sensitive to the crystal structure and constitute a convenient probe for looking at small changes in the structure, especially at low temperatures where there is a lack of X-Ray data. As well known examples, the case of LTT (Lithium Thallium Tartrate) where the absorption band observed at 21 cm^?1 at room temperature softens down to 8 cm^?1 at the Curie temperature (T_c = 12 K), and LiNH₄SO₄ which has a phase transition at 26 K, will be considered.

It is less known that some ferroelectric crystals can be studied as very thick single crystal plates (thickness t up to 10 mm) at 4 K, and they show in some cases a far IR transmission that is much higher than expected from the study of thin plates (i.e. t = 20 μm). In fact the transmission does not decrease very much when thickness is higher than some specific value t ₀/2. The crystal is not homogeneous at 4 K. A model with a far IR absorbing surface layer (thickness t ₀/2) and a transparent bulk is a good first approximation.

At some temperature T ₀ located between liquid helium and liquid nitrogen temperatures, the center of the bulk undergoes a phase transition from the absorbing phase into the transparent one. When temperature is still lowered, the transparent phase is extended towards the surface with an incommensurate phase between the surface and the bulk.     

IR/Raman spectroscopy and DFT calculations of cyclic di‐amino acid peptides. Part III: comparison of solid state and solution structures of cyclo(L‐Ser‐L‐Ser)

B3‐LYP/cc‐pVDZ calculations of the gas‐phase structure and vibrational spectra of the isolated molecule cyclo(L ‐Ser‐L ‐Ser), a cyclic di‐amino acid peptide (CDAP), were carried out by assuming C₂ symmetry. It is predicted that the minimum‐energy structure is a boat conformation for the diketopiperazine (DKP) ring with both L ‐seryl side chains being folded slightly above the ring. An additional structure of higher energy (15.16 kJ mol⁻¹) has been calculated for a DKP ring with a planar geometry, although in this case two fundamental vibrations have been calculated with imaginary wavenumbers. The reported X‐ray crystallographic structure of cyclo(L ‐Ser‐L ‐Ser), shows that the DKP ring displays a near‐planar conformation, with both the two L ‐seryl side chains being folded above the ring. It is hypothesized that the crystal packing forces constrain the DKP ring in a planar conformation and it is probable that the lower energy boat conformation may prevail in the aqueous environment. Raman scattering and Fourier‐transform infrared (FT‐IR) spectra of solid state and aqueous solution samples of cyclo(L ‐Ser‐L ‐Ser) are reported and discussed. Vibrational band assignments have been made on the basis of comparisons with the calculated vibrational spectra and band wavenumber shifts upon deuteration of labile protons. The experimental Raman and IR results for solid‐state samples show characteristic amide I vibrations which are split (Raman: 1661 and 1687 cm⁻¹, IR: 1666 and 1680 cm⁻¹), possibly due to interactions between molecules in a crystallographic unit cell. The cis amide I band is differentiated by its deuterium shift of ∼30 cm⁻¹, which is larger than that previously reported for trans amide I deuterium shifts. A cis amide II mode has been assigned to a Raman band located at 1520 cm⁻¹. The occurrence of this cis amide II mode at a wavenumber above 1500 cm⁻¹ concurs with results of previously examined CDAP molecules with low molecular weight substituents on the C^α atoms, and is also indicative of a relatively unstrained DKP ring. Copyright © 2009 John Wiley & Sons, Ltd.     

Nanoclusters in mixed crystals Hg<Subscript>2</Subscript><Emphasis Type="Italic">Hal</Emphasis><Subscript>2</Subscript>

The Raman spectra of mixed Hg₂(Br,I)₂ and Hg₂(Cl,Br)₂ crystals were investigated. The multimode behavior of optical vibrations induced by presence of three types of molecules (Hg₂ Hal′₂, Hg₂ Hal″₂ and Hg₂ Hal′Hal″) in the crystals was observed experimentally and is discussed theoretically. Phase transition effects such as soft modes, density of states, IR vibration branches, and anti- and ferroelectric nanoclusters induced by polar Hal′-Hg-Hg-Hal″ molecules and their immediate environment, were observed in the Raman spectra.     

Structural changes in perylene from UV Raman spectroscopy up to 1 GPa

Vibrational properties and structural changes under pressure of a highly luminescent molecular organic crystal have been investigated by ultraviolet resonant Raman spectroscopy with a 244‐nm excitation. Resonant Raman modes of α‐perylene crystal up to 1GPa were followed under hydrostatic pressure in an anvil cell with a sapphire window transparent to ultraviolet light. Nonlinear evolution of intra‐molecular modes is induced by pressure. Abrupt shifts of Raman wavenumbers suggest structural and planar modifications of the molecules in the crystal. We interpret these shifts as a first‐order phase transition to a lower volume of unit cell. The luminescence of perylene crystal is gradually modified as a consequence of these structural changes. The present experimental setup allows investigating with Raman spectroscopy very luminescent molecules involved in chemical reactions and molecular organic crystals under relatively high pressure (up to 1GPa). Copyright © 2016 John Wiley & Sons, Ltd.