Phonon transport in periodically and quasi-periodically modulated cylindrical nanowires.

Phonon transport in periodically modulated cylindrical nanowire (PMCN) and quasi-periodically modulated cylindrical nanowire (QPMCN) is comparatively studied. It is shown that the transmission coefficient and thermal conductance for PMCN is greater than the corresponding values for QPMCN. At low frequencies, a wide stop-frequency gap due to the destructive interference between the incoming and back waves can be clearly observed here. For PMCN, such stop-frequency gap seems to be insensitive to the change of N (the periodic number). For QPMCN, however, its breadth increases with the increase of N (the Fibonacci number). When N is increased, the thermal conductance for PMCN presents a distinct change from the decrease to the constant, while QPMCN has a tendency of monotonous decrease. A brief discussion on these results is made.

Novel 3-substituted N-methylcarbazole-imidazolium salt derivatives: Synthesis and cytotoxic activity.

A series of novel 3-substituted N-methylcarbazole-imidazolium salt derivatives has been prepared and evaluated in vitro against a panel of tumor cell lines (Hep G-2, Hela and PC12). The results suggest that the presence of substituted 2-methyl-imidazole or imidazole ring and substitution of the imidazolyl-3-position with a naphthylacyl or 4-bromophenacyl group were important for improving cytotoxic activity. Compounds 17, 18, 27, and 28 with 4-bromophenacyl and naphthylacyl groups displayed good activities with IC50 values of 0.09-7.20 µm against three tumor cell lines investigated and more active than DDP. Compound 35 exhibited cytotoxic activity selectively against Hela cell.

Novel dibenzo[b,d]furan-1H-1,2,4-triazole derivatives: Synthesis and antitumor activity.

Twenty-four new dibenzo[b,d]furan-1H-1,2,4-triazole derivatives were synthesized and investigated for in vitro cytotoxic activity against five tumor cell lines. The results show that the substitution at 4-position of the 1,2,4-triazole with a benzyl, 4-bromophenacyl or naphthylacyl group could be crucial for prommoting cytotoxic activity. Especially, compound 28 was found to be the most powerful derivative with IC50 values lower than 3.50 µM against five investigated tumor cell lines, while compound 19 showed selective activity against leukemia (HL-60) and breast carcinoma (MCF-7) cell lines with IC50 values of 0.80 and 1.76 µM, respectively. Compound 19 can induce cell cycle arrest at G2/M phase and apoptosis in SMMC-7721 cells.

Protein A immunoadsorption therapy in the highly sensitized kidney transplant candidates.

BACKGROUND: Sensitization in transplant candidates increases risk of irreversible immunologic injury of graft in the early period postoperatively. Elimination of anti-human leukocyte antigen (HLA) antibodies using protein A immunoadsorption (IA) might benefit these patients. METHODS: Protein A IA was used in 21 patients with high panel reactive antibody (PRA). The patients had IA 1 - 6 times (median 5 times) with the interval period was 2 - 5 days (median 2.5 days). RESULTS: Total 67 IA procedures were carried out smoothly in all patients. IA treatment reduced PRA I (pre (31.4 ± 3.8)% vs. post (24.4 ± 3.4)%, P < 0.01) and II (pre (37.1 ± 4.3)% vs. post (34.1 ± 3.9)%, P < 0.01). However, PRA did not change in some patients after the treatment. The serum immunoglobulin (IgG, IgM and IgA) and complement C3, C4 level were decreased significantly. Hemoglobin and albumin levels were slightly decreased associated with IA procedures. Flu-like symptoms were observed in a few of cases during the procedure but generally mild and transient. CONCLUSION: Protein A IA is capable to efficiently remove serum immunoglobulin and complement, reduce HLA class I and class II PRA in high sensitized transplant candidates, which is likely to benefit the kidney transplantation in these patients.

Correlation between the iron, magnesium, potassium and zinc content in adolescent girls' hair and their academic records.

BACKGROUND: The aim of this study is to investigate the correlation between school academic records and the iron, magnesium, potassium, and zinc content in adolescent girls' hair. METHODS: The iron, magnesium, potassium, and zinc content in hair samples from 148 adolescent girls was determined by atomic absorption spectrometer. Their academic records from 2 school semesters were interrelated. RESULTS: There was a positive correlation between magnesium (r = 0.20; p = 0.016), and zinc (r = 0.31; p = 0.001) content in the hair and academic records. Conversely, the academic records had an inverse correlation with the potassium content (r = -0.23; p = 0.019). CONCLUSION: The content of magnesium, potassium, and zinc in adolescent girls' hair has a certain correlation with their learning performance. The exact effects of these three trace elements on adolescent learning performance warrants further study.

[Primitive research on the effect of FSH autoantibody on the spermatogenic capability of the rat testis].

OBJECTIVE: To establish rat models of FSH autoantibody and to investigate the effect of FSH autoantibody on the spermatogenic capability of rat testis. METHODS: Thirsty 21-day old SD rats were randomly divided into an experimental and a control group of equal number. A specific polypeptide corresponding to the rat FSHbeta subunit was synthesized and coupled to (keyhole limpet hemocyanin) KLH. The rats in the experimental group were immunized with polypeptide-KLH and these in the control group with KLH. Further immunization was performed every 2 weeks for 7 times. On the 77th, 91st and 105th day of the immunization, 5 rats from the experimental group and another 5 from the control group were killed. Then the structures of the seminiferous tubule and epididymal sperm were observed by light and electron microscope, respectively. Meanwhile, the counts of sperms and the percentage of swelled sperm were calculated. And the level of serum testosterone was detected by enzyme-linked immunospecific assay (ELISA). RESULTS: The titer of the anti-polypeptide antibody was 1:200 on the 49th day of the immunization, and reached 1:400 on the 63rd. Compared with the control group, the percentage of swelled sperm significantly decreased on the 91st day (60.4 +/- 6.23 vs 50.60 +/- 3.05, P < 0.05), and the number of spermatogenic cells and sperms in seminiferous tubules reduced on the 105th day in the experimental group, the counts of sperms (46.08 +/- 6.56 vs 32.53 +/- 3.41) and the percentage of swelled sperm (60.60 +/- 5.86 vs 48.60 +/- 3.85) significantly lower (P < 0.05), while the level of serum T significantly higher than that in the control group (P < 0.05). CONCLUSION: FSH autoantibody might cause testis dyszoospermia.

[Construction of N-LMP1 transgenic mice with the specific regulation region in nasopharynx].

In order to elucidate the role of EBV-LMP1 in the nasopharyngeal carcinogenesis, the expression vector was constructed with subjecting the N-LMP1 gene to double regulation of two specific regulators: EDL-2 and PLUNC-p. The N-LMP1 related transgenic mice model has been constructed successfully by pronucleus microinjection. 58 founder mice were born, 4 of which were founded to be positive by PCR and Southern blot. Immunohistochemistry assay showed that N-LMP1 protein was expressed in the nasopharynx, tongue and forestomach of transgenic mice.

[Suppression subtractive hybridization and its application in study of tumors].

Suppression subtractive hybridization (SSH) has been recently reported as a differential display technique at the basis of suppressive polymerase chain reaction(PCR). This technique has such advantages as easy and feasible, highly specific, capable of separating the low abundant specific fragments. Now it has been successfully applied in the study of tumors, developing biology, immune regulations, etc. Here we summarized its principle, method, and advances in the study of tumors, then analyzed its merits, defects, and applicable potentials.

[Effect of liposome on permeability and drug retention of sodium fluorescein in rat skin: an experimental study].

OBJECTIVE: To investigate the effect of liposome on the permeability and drug retention of sodium fluorescein(NaFl) in rat skin. METHODS: With an improved Franz diffusion cell and 0.125% NaFl liposome suspension as the model drug, in vitro measurement of percutaneous absorption and skin reservoir capacity for NaF1 was conducted using a fluorescence spectrophotometry at 4 and 12 h respectively after the diffusion experiment had started, and distribution of the fluorescence in rat skin was observed under fluorescence microscope at 4 h penetration experiment. NaFl solution of the same concentration as the model drugs served as the control for this experiment. RESULTS: In comparison with NaFl solution, liposomal NaFl suspension resulted in larger amount of NaFl retention in rat skin but smaller amount in the receiver cell in a four-hour Franz diffusion test, with also higher fluorescence intensity in the skin, especially the skin around the hair follicles. CONCLUSION: Local high drug concentrations can be achieved in the skin by liposomal suspension of water soluble drug for more effective treatment of skin diseases.