Biomedical subjects

P Ni

Publications and source records attributed to P Ni.

13 recordsLinked to original sources

PubMed2006

Excimer laser pumped by an intense, high-energy heavy-ion beam.

High-energy heavy ions are an ideal tool to generate homogeneously excited, extended volumes of nonthermal plasmas. Here, the high-energy loss (dE/dx) and absolute power deposition of heavy ions interacting with matter has been used to pump an ultraviolet laser. A pulsed 70 MeV/u 238U beam with up to 2.5 x 10(9) particles in approximately 100 ns beam bunches was stopped in a 1.2 m long laser cell filled with a 1.6 bar Ar-Kr-F2 mixture (typically 50%:49.9%:0.1%). Laser effect on the 248 nm KrF* excimer transition is clearly demonstrated.

Journal Article↗

PubMed2005

Proposal for the study of thermophysical properties of high-energy-density matter using current and future heavy-ion accelerator facilities at GSI Darmstadt.

The subject of high-energy-density (HED) states in matter is of considerable importance to numerous branches of basic as well as applied physics. Intense heavy-ion beams are an excellent tool to create large samples of HED matter in the laboratory with fairly uniform physical conditions. Gesellschaft für Schwerionenforschung, Darmstadt, is a unique worldwide laboratory that has a heavy-ion synchrotron, SIS18, that delivers intense beams of energetic heavy ions. Construction of a much more powerful synchrotron, SIS100, at the future international facility for antiprotons and ion research (FAIR) at Darmstadt will lead to an increase in beam intensity by 3 orders of magnitude compared to what is currently available. The purpose of this Letter is to investigate with the help of two-dimensional numerical simulations, the potential of the FAIR to carry out research in the field of HED states in matter.

Journal Article↗

PubMed2001

[Complex segregation analysis of systemic lupus erythematosus].

OBJECTIVE: To explore the genetic model of systemic lupus erythematosus(SLE). METHODS: Complex segregation analysis was performed by using statistical analysis for genetic epidemiology-REGTL(SAGE-REGTL). The genetic model and gene frequency were estimated. 300 pedigrees with SLE were collected from 300 patients as probands. RESULTS: The complex segregation analysis found the genetic model of SLE to be additive,the gene frequency 0.336. The authors believe the possibility of some different modes coexisting under different circumstances. The genetic effect on young man is stronger than that on old one. CONCLUSION: This study suggests that the genetic mode of SLE could be the major gene trait, and additive mode is the best fitted one.

Adolescent↗

PubMed2001

[Association between asthma and the polymorphism of HLA-DQ genes].

OBJECTIVE: To investigate association between asthma and HLA-DQ genes in Chinese asthma family. METHODS: HLA genotyping was done for HLA-DQ using polymerase chain reaction-sequence specific primers (PCR-SSP) in 98 members of 32 Chinese asthma families and 67 normal controls. RESULTS: The allele frequencies of DQA1 * 0101 and DQA1 * 0601 in asthmatics (40.0% and 45.0% respectively) were significantly higher than those in normal controls (16.4% and 13.4% respectively; chi(2) = 6.1860, P < 0.05, RR = 3.39 and chi(2) = 11.609 0, P < 0.01, RR = 5.27 respectively). The allele frequencies of DQB1 * 0303 and DQB1 * 0601 in asthmatics (55.0% and 47.5% respectively) were also significantly higher than those in normal controls (13.7% and 13.7% respectively; chi(2) = 15.740 0, P < 0.01, RR = 7.68 and chi(2) = 10.930 0, P < 0.01, RR = 5.69 respectively). The allele frequency of DQ * 0201 (39.4%) was significantly higher in members with positive specific IgE response to dermatophagoides than that in non-atopy members (12.0%) in asthma family (t = 2.382 5, P < 0.05). CONCLUSION: HLA-DQA1* 0101, DQA1 * 0601 and HLA-DQB1 * 0303, DQB1 * 0601 may be the susceptible alleles of asthma. HLA-DQB1 * 0201 allele may limit the specific IgE response to dermatophagoides.

Adolescent↗

PubMed2000

Genetic epidemiology study of pathological myopia.

OBJECTIVE: To explore the genetic epidemiology of pathological myopia (PM), including hereditary and genetic model. METHODS: The simple segregation analysis was done by SEGRANB. The values of segregation ratio p and the proportion of sporadic cases x were estimated. The complex segregation analysis was performed using SAGE-REGD. The genetic model and gene frequency were estimated. The 62 pedigrees with PM were random samples from hospital patients. RESULTS: By simple segregation analysis, the genetic pattern of N*N is autosomal recessive and the frequency of sporadic cases is approximately 65.72%. The genetic pattern of A*N may be autosomal recessive (but autosomal dominant cannot be excluded), the frequency of sporadic cases is approximately 35.14%. By complex segregation analysis, the genetic model of PM is autosomal recessive and the gene frequency is 0.147385. CONCLUSION: PM is compatible with autosomal recessive inheritance (autosomal dominant not excluded ), the sporadic cases are existent and the gene frequency is 0.147385.

Female↗

PubMed2000

[The association and linkage analysis between the FcgammaR II a-131 and system lupus erythematosus].

OBJECTIVE: To shed light on the relationship between FcgammaR II a-131 and systemic lupus erythematosus(SLE) in southern Chinese Han population. METHODS: A population-based and family-based study was carried out. FcgammaR II a-131 of each subject was measured by using PCR-allele specific oligonucleotide hybridization(ASO) method. RESULTS: (1) The distribution of FcgammaR II A-131 genotype in cases is significantly different from that in controls (P<0.05). So is the frequency of FcgammaR II aR-131 allele (P < 0.01) which suggests that subjects who have R131 allele tend to be more susceptible to SLE. The subjects with R/R131 homozygous genotype have a higher risk of suffering from SLE. (2) The distribution of FcgammaR II a-131 varies in different races, with identical distribution type among Chinese and Japanese. (3) The results of family-based association analysis and transmitted/disequilibrium test(TDT) suggest that there is not any linkage evidence between FcgammaR II a-131 and SLE. Possibly, the sample size was too small to get positive result. CONCLUSION: This study suggests that FcgammaR II a-131 is a major factor predisposing to the development of SLE in southern Chinese Han population.

Alleles↗

PubMed1999

[Studies of microsatellite instability and loss of heterozygosity at chromosome 17 in non-small cell lung carcinoma].

OBJECTIVE: To identify the presence of microsatellite instability (MI) and loss of heterozygosity (LOH) in non-small cell lung carcinoma (NSCLC). METHODS: Four microsatellite markers TP53(17p13.1), THRA1 (17q11.2-12), D17S579(17q12-21) and D17S855(17q21) were used to examine 35 cases of NSCLC tumor-normal paired tissues for MI and LOH at chromosome 17 using PCR based analysis. RESULTS: 22 of 35 tumors(63%) displayed MI or LOH. 14 tumors(40%) exhibited MI, 11 tumors(31%) exhibited LOH, while 3 tumors (9%) exhibited MI and LOH concurrently. The frequency of MI or LOH was obviously higher in the early-stage(stages I and II, 79%) than in the advanced-stage (stage III, 44%), P < 0.05. However, the frequency of MI or LOH had no significant difference between high-grade differentiated NSCLC tumors and low-grade ones, P > 0.05. No relationship was observed between the presence of MI or LOH and the histologic subtype of NSCLC, P > 0.05. CONCLUSIONS: The results suggest that MI and LOH at chromosome 17 may play a significant role in the development of NSCLC. The high frequency of MI or LOH in the early-stage tumors indicates that these genetic alterations could occur early during NSCLC development.

Carcinoma, Non-Small-Cell Lung↗

PubMed1988

Automatic determination of urinary 4-hydroxy-3-methoxymandelic (vanillylmandelic) acid by liquid chromatography with electrochemical detection.

An automated liquid chromatographic method for the determination of urinary concentrations of 4-hydroxy-3-methoxymandelic acid (VMA) is described. Urine samples are purified by solid-phase extraction on an anion-exchange cartridge and automated on-line chromatographic elution is carried out using a Varian AASP (advanced automated sample processor) system. The column effluent is monitored with an electrochemical detector using a glassy carbon working electrode. The method allows the determination of VMA in 0.05 ml of normal urine with a relative standard deviation of less than 3%. The analysis time can be shortened by use of back-flushing technique, and the correlation with a classical (but non-automated) VMA analysis method is excellent.

Chromatography, High Pressure Liquid↗

PubMed1987

[Assay of clomipramine and its demethylated derivative by liquid chromatography].

Clomipramine and desmethylclomipramide are determined on 1 ml of human blood plasma, after extraction with hexane and high-performance liquid chromatography using a cyanopropyl silane column and UV detection at 280 nm. Imipramine and desipramine are used as internal standards. The methods allow detection limits of 5 micrograms/l; 15.9 nmol/l (clomipramine) to 10 micrograms/l; 33.2 nmol/l (desmethylclomipramine). The precision of the method at clomipramine concentrations of 0.05 to 0.2 mg/l was indicated by a coefficient of variations less than 6% for clomipramine and less than 7% for desmethylclomipramine.

Chromatography, Liquid↗

PubMedDate not supplied

Preparation and properties of polyurea microcapsules with non-ionic surfactant as emulsifier.

Polyurea microcapsules containing oily substances were prepared by using cyanate and polyamine as the monomers with non-ionic surfactant as the emulsifiers. Results showed that TDI-DETA microcapsules had the best stability. The mean diameter decreased and the size distribution curves became narrower and sharper as the stirring speed and the emulsifier concentration during emulsification increased. Addition of Tween 80 to aqueous solution containing OP led to an increase in microcapsule diameter and wider distribution of microcapsules due to the changes in interfacial tension. The isoelectric point of the polyurea microcapsules was found to be pH 5.8.

Capsules↗

PubMedDate not supplied

Study on polyamide microcapsules containing oily liquids.

Oily liquids were microencapsulated within polyphthalamide membranes with dodecyl sulphonate sodium (DSS) as an emulsifier. The mean diameter and the distribution, as well as the zeta-potential, of the microcapsules were analysed. It was found that the mean diameter decreases with an increase in stirring speed and emulsifier concentration during the emulsification step. The addition of DSS to aqueous phase resulted in a decrease in zeta-potential of the microcapsules.

Capsules↗

PubMedDate not supplied

Effect of operation variables and monomers on the properties of polyamide microcapsules.

Oil containing microcapsules were prepared by using phthaloyl dichloride as an oil-soluble monomer and diethylene triamine (DETA) as a water-soluble monomer. The diameter of the microcapsules decreased and their distribution became narrower and sharper as the emulsifying time was increased within the initial period of 45 s, beyond which no appreciable changes in the diameter and its distribution were observed. Once DETA was introduced into the aqueous solution to initiate the interfacial polycondensation reaction, reducing the stirring speed diminished the formation of the membrane fragments, but resulted in an increase in the microcapsule diameter. This indicates that the strength of the initial membrane is not strong enough to prevent the microcapsules from coalescing. Raising the volume fraction of the dispersed phase led to a larger diameter and a wider distribution of the microcapsules. When ortho-, meta- or para-phthaloyl dichloride was used as the oil-soluble monomer, both the diameter and the zeta-potential of the microcapsules decreased in the order: ortho-->meta-->para-, indicating that the steric effect of the monomers plays an important role in the microencapsulation process.

Capsules↗

PubMedDate not supplied

A study of the stability of W/O/W multiple emulsions.

The stability of W/O/W emulsions has been studied in batch agitators. The surfactants suitable for W/O/W emulsions were screened and the factors affecting the emulsion stability were also studied. Results showed that polyamine E644 was an excellent emulsifier for W/O emulsions since the emulsion stabilized by it has not only good stability but also shows smaller swelling. The stability of the emulsion increases with increase in membrane viscosity and concentration of surfactant, but decreases with increase in concentration of the internal reagent in the internal phase and the carriers in the membrane. Raising the agitation speed and the time for preparing the W/O emulsion is beneficial to membrane stability due to formation of smaller internal droplets, but raising the speed for dispersing the W/O emulsion in the external phase results in an increase in membrane breakage.

Chemistry, Pharmaceutical↗