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Biomedical subjects

K Xue

Publications and source records attributed to K Xue.

12 recordsLinked to original sources
PubMed2002

Variable-temperature scanning tunneling microscopy and scanning tunneling spectroscopy study on copper phthalocyanine ultrathin films on a Au(111) surface.

Variable-temperature high-resolution scanning tunneling microscopy (STM) images reveal that well-ordered copper phthalocyanine (CuPc) strips can be self-assembled by depositing CuPc molecules on a Au(111) surface. The self-assembled strips are supposed to result from the balance of the intermolecular interaction and the interaction between the molecules and substrate during annealing. The energy band (approximately 1.9-2.1 eV) of CuPc, measured by scanning tunneling spectroscopy (STS), is comparable to the optical band gap (approximately 1.7 eV). Spectroscopic measurements confirm that a dipole layer and/or an effect of image force exist at the CuPc/Au(111) interface.

Crystallization↗
PubMed2001

Polymorphisms of the CYP1A1 and GSTM1 genes in relation to individual susceptibility to lung carcinoma in Chinese population.

Cytochrome P450 1A1 (CYP1A1) and glutathione S-transferase M1 (GSTM1) metabolize tobacco-related carcinogens. To investigate the prevalence of CYP1A1 and GSTM1, and their association with increased risk of lung carcinoma in Chinese, allele-specific PCR and multiplex PCR technique were employed to identify the genotypes of CYP1A1 and GSTM1 in a case-control study of 106 lung carcinoma patients with histopathological diagnosis and 106 matched controls free of malignancy in Jiangsu Province, China. Logistic regression analysis was performed to calculate the odds ratio (OR) and 95% confidence intervals (CI). The results showed that individuals with GSTM1 null, and the combined GSTM1 null/CYP1A1 Ile/Val or GSTM1 null/CYP1A1 Val/Val had an elevated risk of lung carcinoma, with the OR, 1.92 (P=0.02; CI, 1.07-3.46), 3.27 (P=0.01; CI, 1.23-8.84) and 9.33 (P=0.04; CI, 1.01-217.42), respectively. Light smokers (<30 pack-years) carrying GSTM1 null genotype were shown to have the increased risk to lung carcinoma (OR=3.47; CI, 1.13-7.57). Our study suggested that the null GSTM1 genotype, independently or in combined with at least one Val allele of CYP1A1, might affect the genetic susceptibility for lung carcinoma in Chinese population.

Adult↗
PubMed2001

[Polymorphisms of the CYP1A1 and GSTM1 genes and their combined effects on individual susceptibility to lung cancer in a Chinese population].

OBJECTIVE: To investigate the polymorphisms of CYP1A1 and GSTM1 genes as well as their separate and combined effects on individual susceptibility to lung cancer. METHODS: In the matched 106 pairs of patients with lung cancer and non-cancer control persons, genomic DNA were prepared from peripheral blood samples. The genotypes of CYP1A1 Ile/Val and GSTM1+/0 polymorphisms were detected by the allele-specific(AS)-PCR and multidifferential(MD)-PCR. RESULTS: Individuals with genotype Val/Val of CYP1A1, genotype 0/0 of GSTM1, combined genotypes GSTM1 0/0 and CYP1A1 Val/Val, or combined genotypes GSM1 0/0 and CYP1A1 Ile/Val had higher relative risk than those with the corresponding common genotypes and combined genotypes; their odds ratios were 4.02(P=0.03), 1.92(P=0.019), 9.38(P=0.04) and 3.27(P=0.01), respectively. CONCLUSION: There is a synergy of susceptible genotypes GSTM1 0/0 and CYP1A1 Val/Val or CYP1A1 Ile/Val to enhance the individual susceptibility to lung cancer.

Adult↗
PubMed1999

Possible experimental measure theory for the XXX-Heisenberg chain.

Raising and lowering operators for the XXX-Heisenberg chain are derived explicitly; as a result the dipole moment operator is established. Based on the dipole transition mechanism in an external time-dependent magnetic field, we propose a possible experimental measure theory to detect the energy spectrum of the spin chain.

Journal Article↗
PubMed1999

Test of a vertical scan mode in 3-D imaging of residual limbs using ultrasound.

We have developed a new ultrasound system for imaging residual limbs that employs two scan modes: a vertical scan mode (VSM) primarily used for capturing the skin surface, and a horizontal compound scan mode (HCSM) primarily used for imaging the internal tissue structures. Since the HCSM was described previously (J Rehabil Res Dev 1997;34(3):269-78), the main purpose of this article is to elucidate the principle of reconstructing the skin surface using the new VSM and to report the accuracy of volumetric measurement based on this reconstruction method. For a residual limb with a length of up to 26 cm, the vertical scan takes about 80 s. The acquired skin surface has a resolution of 144 points per circumference in the transverse direction and a resolution of 28 points per cm in the longitudinal direction. The measurement accuracy of the system is tested using a cylindrical phantom and a custom-made limb model. The diameter of the phantom measured by the ultrasound method is 113.8 +/- 0.23 mm, compared with a value of 113 mm measured by a caliper. For the limb model, cumulative segment volumes measured by the ultrasound method are compared with those measured by the hydrostatic weighing method. The relative errors are <1%. This study demonstrates the feasibility of using ultrasound to perform limb measurement for prosthetic CAD/CAM applications.

Artificial Limbs↗
PubMed1997

3-D imaging of residual limbs using ultrasound.

In this article, a method of using ultrasound to image a residual limb is presented. The method employs a compound scanning technique to reconstruct a cross-sectional image (a slice) of the limb in a transverse plane. By scanning the limb in many transverse planes, a three-dimensional (3-D) volumetric image can be obtained from which either a transverse slice, a longitudinal cross section, or a 3-D surface of the limb can be displayed. The compound process circumvents the problems associated with the large attenuation of bones and enables reconstruction of a complete image of bones and adjoining tissues. In addition, the compound process improves the lateral resolution and reduces the speckle noise. Results obtained from a pair of thin wires, a contrast-resolution phantom, and a human limb demonstrate the beneficial effects of the compound process. To maximize the benefits, however, an accurate pixel registration in image reconstruction is essential. Sources of pixel misregistration and the potential means of minimizing misregistration are discussed.

Amputation Stumps↗
PubMed1996

A PC-based ultrasonic data acquisition system for computer-aided prosthetic socket design.

A PC-based ultrasound data acquisition system has been developed which uses compound scanning techniques to image a residual limb in a water tank. From the received ultrasonic eco data, the system produces cross-sectional images and reconstructs a three-dimensional (3-D) model of the limb. A commercial software for computer-aided prosthetic socket design was modified so that it can display both the external shape and cross-sectional image of the limb and allow the prosthetist to perform socket design with the help of a visualization of the limb's internal structure. The image resolution and measurement accuracy of the system were tested using a wire phantom and a contrast tissue mimicking phantom, respectively. Preliminary results from amputee patients are presented and the sources of measurement error are discussed.

Computer-Aided Design↗
PubMed1992

[Preliminary studies of dose-effect relationship in overdose irradiation of electron beam with high energy--comparative observation of several indices of nuclear damage in lymphocyte of human peripheral blood].

In this paper we studied the relationship between doses (5-40Gy) and indices of nuclear damage in lymphocyte of human peripheral blood irradiated by 10 Mev of electron beam to explore possibility of establishing biodosimeter of overdose irradiation. The main results are as follows: (1) The frequency of micronucleated cell (MNCF), the frequency of irregular nucleus (INF), the frequency of pyknotic nucleus (PNF), the frequency of karyorrhetic nucleus (KNF) and the frequency of nuclear anomalies (NAF = MNCF + INF + PNF + KNF) increased along with increase of irradiation dose. Within the range of 0-20Gy indices of nuclear damages which were linear with irradiation doses are NAF (P less than 0.01), MNF (P less than 0.01), INF (P less than 0.05) and KNF (r = 0.8972), P greater than 0.05). Within the range of 0-40Gy the index of nuclear damage which was linear with irradiation dose was PNF (P less than 0.01) alone. (2) As compared with chromosome aberration analysis nuclear anomaly test is a more rapid and convenient assay, and can detect overdose radiation damage using chromosome analysis.

Cell Nucleus↗
PubMed1992

[Preliminary studies of the relationship between micronucleus formation and cell cycle. IV. Micronucleus formation induced by chemical mutagens at G0, G1, S and G2 phases of human lymphocytes].

In this paper the authors studied quantitatively the micronucleus formation at various phases of interphase in human lymphocytes induced by chemical mutagens by means of control of cell culture intervals, autoradiography and block of metaphase cells etc. The results show that mutagenic anti-tumor drugs: bimolane (treatment in vitro) and thio-tepa etc. (treatment in vivo) can induce micronucleus formation at various phases of interphase in lymphocytes. The frequency of micronucleus (MNF) induced at G1 phase is significantly higher than that at G0 and G2 phase. The MNF at S phase of cells is obviously lower than at G1. This result suggests that most of the micronucleated cells at G1 phase do not enter S phase and micronucleus rarely form at S phase of cells.

Adolescent↗
PubMed1991

[Influence of site and method of implantation on growth and invasion of human lung adenocarcinoma in nude mice].

In the present study, the growth and invasion of human lung adenocarcinoma cells (LTEP-a-2) transplanted into different sites (s.c. and footpad) and using different methods (including inoculation of tumor cell suspension and tumor fragment) in 12 nude mice were examined. The animals were divided into two groups; namely, subcutaneous inoculation (6 nude mice) and footpad inoculation (6 nude mice). Two transplantation sites were selected in each mouse; i.e. the tumor cell suspension was implanted into one site, and the tumor fragment was implanted into the opposing site of the same mouse. In the subcutaneous inoculation group, tumor growth (100%) was accompanied by no invasive behavior (including suspension and fragment). In the footpad inoculation group, 3/6 cases of inoculation by suspension saw tumor growth with invasive behavior; but in the case of tumor fragment transplantation no tumor growth was found. One murine sarcoma was found in the tissues surrounding the human lung adenocarcinoma cells. The mechanism of formation of this murine sarcoma is discussed. Our results show that human tumor growth in nude mice is obviously influenced by the site of inoculation.

Adenocarcinoma↗