Biomedical subjects

Yi-zhuang Xu

Publications and source records attributed to Yi-zhuang Xu.

At least 19 recordsLinked to original sources

PubMed2005

[FTIR spectroscopic explorations of clinical practice of breast cancer].

The authors detected ten normal breast tissue samples and eight breast cancer samples by FTIR spectroscopy with an ATR probe. Nineteen variables of thirteen bands in the spectra were compared using standard statistic methods. The results demonstrated that bands of protein, lipid, carbohydrate, and nucleic acid from cancerous samples were significantly different from those from normal ones: (1) The relative intensity of N-H band increased and amide I band shifted to lower wave number significantly; (2) Symmetric and antisymmetric vibrations of -CH2 group, C=O vibration, and relative intensity of (-CH2)n decreased; (3) The intensity of 1160 cm(-1) band was much weaker than that of 1120 cm(-1); (4) The band of P=O or P-O-C shifted toward lower wave number. The authors believe that FTIR spectroscopy has a promising future in breast cancer diagnosis.

Breast↗

PubMed2005

[The study on the growth process of ZnO nanorods].

Albstract The authors synthesized ZnO nanorods by calcining the precursor composed of PVP and Zn(CH3COO)2.2H2O at 300 degrees C. In order to investigate the growth process of ZnO nanorods, the precursor was calcined for different time (0.5, 3, 12, 24 h) and the corresponding products were measured by TEM, HR-TEM (high-resolution transmission electron microscopic), SAED (selected-area electron diffraction pattern) and XRD. The result showed that there were ZnO crystallites in the precursor of PVP and Zn(CH3COO)2.2H2O, which was dried at 110 degrees C. When the precursor was calcined at 300 degrees C for 0.5 h, ZnO nanorods could be observed with diameter of 50 nm and the nanorods consisted of two parts. One was compact nanorod with diameter of about 30 nm and the other part was ZnO crystallites attaching around the nanorod. This phenomenon indicated that there might be a transverse growth direction of ZnO nanorods at early time of crystal growth. When the precursor was calcined for 3 h, the products were direct and smooth single crystal ZnO nanorods. Further increasing the calcining time at 300 degrees C could improve the length of the ZnO nanorods in a certain extent while the diameter changed a little. The HR-TEM results showed that the growth direction of ZnO nanorods was along c axis.

Hot Temperature↗

PubMed2005

[Spectroscopic studies on different chemical composition between the shell and core of Radix Notoginseng].

Notoginseng (Sanqi) is one of the most important components of famous Chinese recipe (Yunan Baiyao) and possesses a wide variety of applications in clinical practice. It has been found that Sanqi of different size exhibits different curative effects. Such a phenomenon may be attributed to that the chemical constituent from shell region is different from that of core region. To prove the above-mentioned hypothesis, Ultraviolet-Visible (UV-Vis), FTIR, fluorescence spectroscopy, together with high performance liquid chromatography (HPLC) and electrospray ionization mass spectroscopy (ESI-MS) were utilized to study the variation of chemical compositions from shell and core regions of Sanqi. The results demonstrate that the chemical compositions of Sanqi from shell and core regions are different. In summary, differences in chemical composition between Sanqi shell and core were manifested from versatile aspects. Such differences shed a light on the different curative effects of Sanqi.

Chromatography, High Pressure Liquid↗

PubMed2005

[Fluorescence spectra and protonation of ofloxacin].

Fluorescence spectra, ultraviolet spectra and protonation of Ofloxacin (OFL) at different pH values have been studied. In strong acidic solutions, OFL molecule might accept two protons to exist as ternary acid H3L2+ with a maximum emission wavelength (lambdamax) at 505 nm. Along with the increase in pH value, fluorescence spectrum of OFL changed, an iso-fluorescence point at 352 nm was found in the fluorescence excitation spectra, and at the same time, isosbestic points were found in its UV absorption spectra. This spectral feature reveals that H3L2+ gradually lost hydrogen ion combined on C-4 keto oxygen. In the range of pH 2.5 to pH 4, OFL exists as H2L+ with lambdamax at 499 nm. When pH>4, the fluorescence emission peak at 499 nm gradually blue-shifted to 455 nm as pH was increasing, and an iso-fluorescence emission point was formed at 484 nm, indicating the dissociation of hydrogen ion of carboxylic acid at C-3. At about pH 7.0, OFL exists in the dipole ion form HL with lambdamax at 455 nm, which is the strongest fluorescence form. When pH>8, lambdamax red-shift from 455 to 475 nm as pH increases, meanwhile, fluorescence intensity decreases, indicating that HL lost hydrogen ion combined on N-4 of piperazinyl group. When pH>10, OFL exists in anion ion form L-, and fluorescence intensity decreases with pH increasing, but lambdamax remains essentially constant, indicating that medium environment influences the fluorescence property of OFL.

Chemistry, Pharmaceutical↗

PubMed2005

[Characterization of the orientation of polymer material by non-polarized raman laser light spectroscopy].

The non-polarized Raman laser light was used to investigate the anisotropic polymers including polypropylene fiber, nylon 6 flat fiber, and polyethylene pipe. The Raman spectra of the same samples with different location relative to the incident direction of laser beam show obvious differences. The present result extends the application of Raman spectroscopy to the characterization of oriented polymers samples.

Anisotropy↗

PubMed2005

[Spectral properties, protonation and fluorescence quantum yield of ciprofloxacin].

Fluorescence spectra, ultraviolet absorption spectra, and protonation of Ciprofloxacin (CIP) at different pH values have been studied. Fluorescence quantum yield of CIP under neutral condition has been measured. In HCl medium with [H+] > 1 mol x L(-1), CIP molecules (simplified as HL) may accept three protons to exist as H4L3+ with very weak fluorescence, and its maximum fluorescence emission wavelength (lambdamax) is 456 nm. In acidic solution of pH 0 to pH 2, CIP mainly exists as H3L2+ form with lambdamax at 450 nm, and fluorescence intensity is relatively weak and increases with increasing of pH. In the range of pH 2 to pH 4, CIP mainly exists as H2L+ form with a strong fluorescence, and lambdamax is still at 450 nm. When pH>4, lambdamax gradually blue-shifts to 414 nm, fluorescence intensity slightly decreases as pH increases, and at the same time an evident change in ultraviolet absorption spectrum is observed, indicating that H2L+ has lost proton to exist as dipole ion form HL. When pH>8, the fluorescence intensity decreases until disappearance as pH increases, indicating that HL has lost proton to exist as non-fluorescence anion ion form L-. In the molecular form changing process, the maximum excitation wavelength of CIP is essentially constant at 275 nm, but the maximum emission wavelength changes obviously. In a buffer solution with pH 7.0, and using quinine bisulphate as a reference, the fluorescence quantum yield of CIP at maximum excitation wavelength 275 nm was measured to be 0.12.

Algorithms↗

PubMed2005

[Novel infrared spectroscopy methods for clinical diagnosis of tumor].

In this paper, the authors have reviewed their investigation on the clinical detection of tumor tissues by infrared spectroscopy in recent ten years. Based on the comparison of different IR spectroscopic methods such as IR transmission spectroscopy, micro-IR spectroscopy etc, the authors found the good consistency of the results of ATR (attenuated total reglection) IR spectroscopic method with those of pathological biopsy. The authors have directly measured the IR spectra of frozen tissues stored in liquid nitrogen and freshly resected tissues, and have realized the measurement of tumor tissues in vito during the operation process using a specially designed IR spectrometer connected with a mid-IR fiberoptic with an ATR probe. The authors have investigated the malignant and normal tissues including parotid, esophagus, stomach, colon, liver, gallbladder, breast, thyroid etc. and compared with the pathological results. The accuracy of this novel IR detection method is more than 90%.

Humans↗

PubMed2004

[The luminescence characteristic of a new novel coprecipitate rare earths complexes].

A new novel coprecipitate rare earths complexes La0.6Eu0.4(BSA)3phen has been synthesized and was chosen as the emitter material in the organic electroluminescent devices: ITO/PVK: La0.6Eu0.4(BSA)3phen/Alq/Al where PVK was used to improve the film-forming and hole-transporting property of the La0.6Eu0.4(BSA)3phen. It has been proved that it exists Förster energy transfer process from La3+ to Eu3+. This device has also been compared with the devices: ITO/PVK: Eu(BSA)3phen/Alq/Al and ITO/PVK: Tb0.6Eu0.4(BSA)3phen/Alq/Al. From the data, it indicated the device has the good purity of red color and good commutation property. The maximum EL brightness of 102 cd x m(-2) had been got.

English Abstract↗

PubMed2004

Discrimination of normal and malignant gastric tissues with FTIR spectroscopy and principal component analysis.

In this paper, the identification of normal and malignant gastric tissues, including 11 cases of cancerous tissues and 10 cases of normal tissues, was investigated using mid-IR spectroscopy and principal componentanalysis (PCA). The results indicated that the difference between cancerous and normal tissues was found in the first principal component. The IR detection and PCA results are in agreement with the biopsy results. The combination of these two methods might provide a new opportunity for clinical application.

Algorithms↗

PubMed2004

[Saltation behavior in excitation spectra of fluorescent molecules].

Excitation spectra are commonly used to study relationship between molecular structure of fluorescent substances and energy transfer during the fluorescence process. It is generally taken for granted that the excitation spectrum of the sample is equivalent to its absorption spectrum, even a copy of the latter. However, exceptions have been found in many cases. Considering various factors that affect the excitation spectra of solution comprehensively, a model has been established to study the behavior of the excitation spectra. After analyzing the model mathematically, including introducing catastrophe theory, we came into the following conclusions: As far as the topological properties are concerned, the excitation spectra are the same as its absorption spectra, provided the concentration of the substance is below a threshold. However, when the concentration is beyond the threshold, the excitation spectra undergo a series of topological saltation, leading to significant a deviation from the absorption spectra. Comparative studies of both excitation and absorption spectra of naphthalene dissolved in n-hexane confirmed the above hypothesis.

Absorption↗

PubMed2004

[Luminescence properties of a new kind of rare earth complexes Tb(m-benzoicacid)3].

The luminescence properties of a new kind of rare earth complex Tb(m-benzoicacid)3 were studied. With the new complex as the dopant and PVK as the host, the film of the mixed system was made, from whose spectra the authors learned that a highly efficient energy transfer process exists. The energy transfer is related to the mass proportion, and the more the mass proportion of Tb in the doped system, the more the emission proportion, and at the same time the emission of PVK is relatively weak. When the mass proportion of Tb(m-benzoicacid)3:PVK is higher than 20%, the emission of Tb is stronger than that of PVK, and plays the main role, while the emission of PVK disappears. The authors used the PVK:Tb(m-benzoicacid)3 system as the emission layer and Alq as the electron-transfer layer, thus the device, whose structure is ITO/PVK:Tb(m-benzoicacid)3/Alq/LiF/Al was formed. From the spectrum of this device, the characteristic emission of Tb can be observed. At the bias voltage of 21 V, a brightness 311 cd x m(-2) was achieved.

English Abstract↗

PubMed2004

[Structural characteristics of infrared spectra for polyaluminum chloride in enhanced reactions of modification].

As an important preparation method of Inorganic Polymer Flocculants (IPFs) with all-round performance, the use of enhanced reactions of modification for Polyaluminum Chlorides (PAC) is a trend of application. In this paper, auctorial-made multicore oligomers as a complexing agent, polysilicate as a crosslinking agent and polyacrylamide as a compounding agent are respectively used to enhance PAC and prepared three kinds of IPFs, named CO-PAC, CR-PAC and PAM-PAC. The Fourier Transform Infrared spectra (FTIR) of the three flocculants show that there have been found new chemical bonds beyond Al-OH in their structures, and each characteristic band of primary group in PAC has a band shift to a lower frequency due to its structural aberration. These evidences suggested that enhanced reactions of modification for PAC are not at all a simple process of physical mix, but a chemical reaction to form other structural characteristics of inorganic polymers. The excellent coagulation behavior of these new flocculants depends mainly on the chemical actions, but there are a little physical effects between the modifiers and PAC.

English Abstract↗

PubMed2004

[The design and application of domestic mid-IR fiber optics].

The combination of mid-IR fiber optics and FTIR has made the non-invasive determination of samples in situ, with long distances, and in vivo possible. In this paper domestic mid-IR fiber optics was improved to investigate the transmission ability of fiber optics and its application to the sample determination. New design was applied to obtaining one bare fiber optics, which has a minor energy loss and higher signal-to-noise ratio. The spectra of H2O/EtOH and tissue samples were measured using the new designed fiber optics and the results show that home-made mid-IR fiber optics can be applied to the field of determination of general and biological samples.

English Abstract↗

PubMed2003

[Interaction between polyamide and zinc salt].

X-ray diffraction and FTIR spectroscopic method have been used to investigate the interaction between the amide group of nylon 6 and zinc chloride. The nylon sample obtained by adding formic acid solution of nylon into aqueous solution saturated by zinc chloride is significantly different from the nylon precipitated after mixing formic acid solution of nylon and water. X-ray diffraction results demonstrate that nylon precipitated from water has crystallization while the sample acquired from saturated solution of ZnCl2 remains amorphous. FTIR spectroscopic study shows that the interaction between zinc ion and the amide group of nylon 6 brings about significant variation of amide I and II bands and prevents the crystallization of nylon. The interaction between nylon and zinc ions may be helpful in the development of a new method of manufacturing new nylon material with superior performance.

Chlorides↗

PubMed2003

[The emission of rare earth complex Eu(asprin)3phen].

Two kinds of electroluminescent devices were fabricated by doping the rare earth complex Eu(asprin)3phen into polymer PVK: (1) ITO/PVK:RE/LiF/Al; (2) ITO/PVK:RE/PBD/LiF/Al. A great difference in the EL spectrum was found between the two kinds of devices. In device (2) the intensity of 594 nm was rather weak compared with that of 614 nm. The spectrum was consistent with the photoluminescence (PL) spectrum under the state of thin film. But in device (1), the peak emission of 594 nm was comparable to that of 614 nm. Preliminary discuss on this phenomenon was made; in device (1), the recombination region was close to the metal cathode, effect of metal cathode on the electroluminescence of the rare earth complex caused the changes of the EL emission which was quite different from the TL emission. The phenomenon was not observed in device (2) whose recombination region was far from the cathode because an electron-transport layer was inserted.

Chelating Agents↗

PubMed2003

[The luminescence character of Eu complexes with derivatives of benzoic acid and different second ligands].

Synthesize eight rare earth europium complexes with derivatives of benzoic acid and different second ligands. We obtained luminescence spectra of these complexes. Although their Eu3+ have about local surrounding symmetry, luminescent intensities are different each other. Because of matching of energy level the complexes with phen is better than with bipy and through the variety structure of spectra show the complexity of Eu3+ hypersensitive transition.

Benzoic Acid↗

PubMed2002

[Study on the photofluorescence of Eu(III) and long chain fatty acid complexes].

The complexes having the compositions of Eu(L1)(3)2H2O,Eu(L1)3phen,Eu(L2)(3)2H2O,Eu(L2)3phen (phen = 1,10-phenathroline,L1 = Dodecanoic acid, L2 = Stearic acid) were synthesized and characterized by elemental analysis and FTIR spectra. Their fluorescence spectra, UV spectra and TEM (Transmission Electron Microscope) have been investigated. The results show that the 5D0-7F1 and 5D0-7F2 transition of Eu(III) are observed in the emission spectrum of the particles at room temperature. As good photoluminescent materials, they may be useful in the regions of EL (Electroluminescence) or macromolecule composite materials doped with rare earth.

Chelating Agents↗

PubMed2002

[Structural variation of o-amino-benzoic acid induced by free electron laser].

Free electron laser (FEL) have been developed as tunable lasers over a wide range of wavelenths. Equipment in the region of 6-16 microns (1,660-630 cm-1) is available in the Beijing free electron laser erected by Institute of High Energy Physics, CAS. In this study we report first measurements of infrared-induced molecular change under irradiation by FEL of 9.414 microns and 6.228 microns, respectively. Taking o-amino-benzoic acid as an example, FTIR characterization indicates that the peak positions of both N-H and C=O stretching vibrations shift before and after the irradiation of FEL. It demonstrates that FEL induces the re-arrangement of H-bonds between COOH and NH2 by stimulating the vibration of carboxyl groups. It suggests that the presence of stable/metastable phases in the title compound.

Electrons↗