Biomedical subjects

Peng Zhang

Publications and source records attributed to Peng Zhang.

At least 37 records · Page 2Linked to original sources

PubMed2006

Preliminary study on eye colour in Japanese macaques (Macaca fuscata) in their natural habitat.

Eye colour in Japanese macaques shows apparent differences between individuals, continuously ranging from orange (bright), through shades of yellow and hazel-blue to dark blue (dark). We arbitrarily classified them into either 'yellow' eyes or 'blue' eyes based on the yellow area occupying in the iris' peripupillary ring. Most Japanese macaques have yellow eyes after infant phase, whilst 19, 17, 12, and 15% of monkeys (>6 months, sexes combined) have blue-eye in studied two groups of Shodoshima and two groups of Takasakiyama, respectively. Frequency of eye colour did not differ between males and females, but significantly differed in each age class. Blue eyes significantly more frequently occurred in newborns, infants and aged monkeys than in juveniles and prime adults. Data from mother-infant pairs indicated eye colour could be inherited from their parents. A case of asymmetric eye colour in Japanese macaques was found from a sample of 1962 individuals. Eye colour variation of Japanese macaques was discussed in relation to those of humans and rhesus macaques. A possible evolutionary model of eye colour in Japanese macaques was discussed.

Age Factors↗

PubMed2006

Investigation on the sonocatalytic degradation of acid red B in the presence of nanometer TiO2 catalysts and comparison of catalytic activities of anatase and rutile TiO2 powders.

Here, the nanometer anatase and rutile titanium dioxide (TiO(2)) powders were introduced to act as the sonocatalysts during the ultrasonic degradation of azo dye-acid red B which was chosen as model compound. The ultrasound of low power was used as an irradiation source to induce TiO(2) particles performing catalytic activity. It was found that the processes of sonocatalytic degradation were different between nanometer anatase TiO(2) and nanometer rutile TiO(2). For nanometer anatase TiO(2) catalyst, the acid red B was mainly oxidated by the holes on the surface of nanometer anatase TiO(2) particles, so that the decolorization and degradation happened at the same time. For the nanometer rutile TiO(2) catalyst, the acid red B was mainly oxidated by the *OH radicals from the ultrasonic cavitation, so that the decolorization of azo bond takes place primarily, and then the degradation of naphthyl ring does. The intermediates of acid red B in the presence of nanometer anatase and rutile TiO(2) powders have been monitored by UV-vis spectra and high performance liquid chromatography (HPLC), respectively. All experiments indicated that the degradation effect of acid red B in the presence of nanometer anatase TiO(2) powder was obviously better than that in the presence of nanometer rutile TiO(2) powder. Hence, the method of sonocatalytic degradation for organic pollutants in the presence of nanometer anatase TiO(2) powder is expected to be promising as an advisable choice for the treatment of organic wastewaters in future.

Azo Compounds↗

PubMed2006

Is it possible to use urodynamic variables to predict upper urinary tract dilatation in children with neurogenic bladder-sphincter dysfunction?

OBJECTIVE: To investigate the possibility of using urodynamic variables to predict upper urinary tract dilatation (UUTD) in children with neurogenic bladder-sphincter dysfunction (NBSD). PATIENTS AND METHODS: The study included 200 children with NBSD, of whom 103 had UUTD and 97 did not; they were examined using routine urological, neurological and urodynamic methods. The group with UUTD was divided into three subgroups (group 1-3, from mild to severe hydronephrosis). A urodynamic risk score (URS) was calculated, including a detrusor leak-point pressure (DLPP) of >40 cmH2O, a bladder compliance (BC) of <9 mL/cmH2O and evidence of acontractile detrusor (ACD). RESULTS: The postvoid residual urine volume (PVR), DLPP, incidences of ACD and DLPP of >40 cmH2O were greater and the BC significantly less in groups 1-3 than in the control group. Moreover, the BC decreased, while the PVR, DLPP and the incidence of DLPP of >40 cmH2O were significantly higher in group 3 than in group 2. The relative safe cystometric capacity of groups 2 and 3 were lower, respectively, than that of the control and group 1, and the relative unsafe cystometric capacity (RUCC) and relative risk rate of cystometric capacity (RRRCC) were significantly greater with the severity of UUTD. The maximum detrusor pressure on voiding or at maximum flow rate, and the Abrams-Griffiths number for voluntary contractile bladders, of the UUTD group were significantly higher than those of the control group. There was a positive correlation between URS and UUTD. CONCLUSIONS: The selective use of urodynamic variables might be valuable for predicting the risk of UUTD in children with NBSD. Decreased BC, and increased DLPP and ACD are the main urodynamic risk factors, and they reciprocally increase the occurrence and grades of UUTD. The grades of UUTD are compatible with increases in RUCC, RRRCC and URS.

Adolescent↗

PubMed2006

Design of a highly sensitive and specific nucleotide sensor based on photon upconverting particles.

We have designed and developed a novel sensor that reports the presence of specific nucleic acids in solutions, based on photon upconverting particles. The significantly high signal-to-noise ratio of photon upconverting particles leads to high sensitivity of the sensor. The sensor does not suffer from photobleaching. It also displays high specificity and self-calibrating capability. We expect nucleotide sensors of this type to be effective for applications in both DNA/RNA detection and protein-DNA/RNA interaction studies.

Journal Article↗

PubMed2006

The effect of visuospatial attentional load on the processing of irrelevant acoustic distractors.

This work investigated the role of cognitive control functions in selective attention when task-relevant and -irrelevant stimuli come from different sensory modalities. We parametrically manipulated the load of an attentive tracking task and investigated its effect on irrelevant acoustic change-related processing. While subjects were performing the visual attentive tracking task, event-related potentials (ERPs) were recorded for frequent standard tones and rare deviant tones presented as auditory distractors. The deviant tones elicited two change-related ERP components: the mismatch negativity (MMN) and the P3a. The amplitude of the MMN, which indexes the early detection of irregular changes, increased with increasing attentional load, whereas the subsequent P3a component, which indicates the involuntary orienting of attention to deviants, was significant only in the lowest load condition. These findings suggest that active exclusion of the early detection process of irrelevant acoustic changes depends on available resources of cognitive control, whereas the late involuntary orienting of attention to deviants can be passively suppressed by high demand on central attentional resources. The present study thus reveals opposing visual attentional load effects at different temporal and functional stages in the rejection of deviant auditory distractors and provides a new perspective on the resolution of the long-standing early versus late attention selection debate.

Adult↗

PubMed2006

Inhibition of human tumor xenograft growth in nude mice by a conjugate of monoclonal antibody LA22 to epidermal growth factor receptor with anti-tumor antibiotics mitomycin C.

Anti-EGFR monoclonal antibodies LA22 and Erbitux bind to different epitopes of EGFR. The chemimmunoconjugates of MMC with LA22 or Erbitux were prepared, and in vitro cytotoxicity assays with A549 cells showed that LA22-MMC was much more potent than Erbitux or Erbitux-MMC. Viabilities of A549 cells treated with LA22-MMC, Erbitux or Erbitux-MMC were 35%, 94%, and 81%, respectively. Immunoscintigraphy of xenografts of human A431 and A549 cells in nude mice both showed that (125)I-labeled-LA22-MMC enriched in tumor sites prominently. Most importantly, in vivo assays showed LA22-MMC was significantly more effective than free drug MMC in the treatment of subcutaneous xenografts of human A431 cells in nude mice (83% inhibition for LA22-MMC and 30% for MMC). We concluded that LA22-MMC could be a very potent drug for treatment of solid tumors.

Animals↗

PubMed2006

Formation and transport of a sand heap in an inclined and vertically vibrated container.

We investigate experimentally the formation and the transportation of a heap formed by granular materials in an inclined and vertically vibrated container. We observe how the transport velocity of heap up the container is related to the driving acceleration, the driving frequency, and the inclination of the container. An empirical law which governs the transport velocity of the heap is presented. An analogous experiment was performed with a heap-shaped Plexiglas block. We propose that the compressive force resulted from pressure gradient in ambient gas plays a crucial role in enhancing and maintaining a heap, and the ratchet effect causes the movement of the heap.

Journal Article↗

PubMed2006

Essence of conservation forms in the traveling wave solutions of higher-order traffic flow models.

This paper shows the essence of conservation forms when applying the weak solution theory to solve the traveling wave solution of a wide cluster in the Payne-Whitham (PW) model. The consideration of the conservation form for the acceleration equation is an important ingredient in the development of higher-order traffic flow models, but it is largely ignored in the research community. To fix the idea, we define two conservation forms for the same PW model, and consequently derive two solutions with different sets of characteristic parameters of the wide cluster. The analytical results are in good agreement with those that are obtained from numerical simulations. Moreover, these two solutions are also shown to be asymptotic to those of the well-known Kühne and Kerner-Konhaüser models with a viscosity term. More importantly, the careful treatment of the conservation form for the acceleration equation closes the important gap in the literature. Without the conservation form, the solution obtained depends very much on the design of numerical schemes, and can be quite arbitrary and may not adequately conform to the physically relevant properties.

Journal Article↗

PubMed2006

Identification of amino acid residues involved in the interaction between measles virus Haemagglutin (MVH) and its human cell receptor (signaling lymphocyte activation molecule, SLAM).

Signaling lymphocyte activation molecule (SLAM; also known as CD150) is a newly identified cellular receptor for measles virus (MV). The interaction between MV Haemagglutin (MVH) and SLAM is an initial step for MV entry. We have identified several novel SLAM binding sites at residues S429, T436 and H437 of MVH protein and MVH mutants in these residues dramatically decrease the ability to interaction with the cell surface SLAM and fail to coprecipitation with SLAM in vivo as well as malfunction in syncytium formation. At the same time, K58, S59 and H61 of SLAM was also identified to be critical for MVH and SLAM binding. Further, these residues may be useful targets for the development of measles therapy.

Animals↗

PubMed2006

Use of X-chromosome inactivation pattern to determine the clonal origins of uterine leiomyoma and leiomyosarcoma.

Uterine leiomyomas (LMs) and leiomyosarcomas (LMSs), both of smooth muscle origin, sometimes coexist in the same uterus. Little genetic evidence exists concerning the developmental relationship between LM and LMS. Using the X-chromosome inactivation pattern of the human androgen receptor gene, we examined the clonality of LM and LMS. Of the 24 patients with LM, 21 had multiple neoplasms; all were clonal and individual LMs derived from separate clones. Of the 20 patients with LMS, 6 exhibited multiple tumors in the uterus, and 4 of these individuals also harbored coexisting uterine LMs. We found all LMSs to be clonal. Separate tumors showed identical pattern of X inactivation in 4 patients, and in 2 other individuals, multiple LMSs developed from independent clones. Among the 4 patients with LMS and coexisting LM, 3 showed the same pattern of X inactivation in LMS and the adjacent LM. In 2 of the 3 patients, the tumor also exhibited a morphological transition between benign cells in LM and malignant cells in LMS, supporting the possibility of transformation from LM to LMS. One patient displayed different clones in LMS and the coexisting LM, indicating their independent origins. We conclude that (i) both LM and LMS are clonal; (ii) different nodules in multiple LM are of independent origins; (iii) multiple lesions of LMS may be either monoclonal or multiclonal; (iv) most LMSs are solitary lesions and are most likely de novo, but an individual LM may undergo "malignant transformation" to a LMS; and (v) some LMSs and coexisting LMs are of independent origins.

Adult↗

PubMed2006

Investigation on transition crystal of ordinary rutile TiO2 powder and its sonocatalytic activity.

The transition crystal TiO(2) sonocatalyst was prepared utilizing the method of ultrasonic irradiation in hydrogen peroxide solution. The sonocatalytic activity of the transition crystal TiO(2) powder was validated through the degradation of methyl orange in aqueous solution by ultrasonic irradiation. The results show that the sonocatalytic activity of the transition crystal TiO(2) powder is obviously higher than that of pure rutile and anatase TiO(2) powders as well as mixed rutile and anatase TiO(2) powders according to the proportion of corresponding transition crystal TiO(2) catalyst. The degradation ratio of methyl orange in the presence of the transition crystal TiO(2) catalyst surpasses 75% within 80 min ultrasonic irradiation, while the degradation ratios are 55.93%, 51.68% and 40.88%, respectively, for rutile, mixed and anatase TiO(2) powders.

Catalysis↗

PubMed2006

Pressure-flow studies in patients with benign prostatic hyperplasia: a study comparing suprapubic and transurethral methods.

AIM: To compare the use of the suprapubic puncture method versus the transurethral method in pressure-flow studies in patients with benign prostatic hyperplasia. METHODS: Twenty-three men with benign prostatic hyperplasia underwent both suprapubic and transurethral pressure-flow studies during a single session. Standard pressure-flow variables were recorded in all patients with both methods, enabling calculation of obstruction using commonly used grading systems, such as the urethral resistance algorithm, the Abrams-Griffith (AG) number and the Schaer linear nomogram. RESULTS: There were statistically significant differences between the methods in the mean values of maximum flow rate (P < 0.05), detrusor pressure at the maximum flow (P < 0.01), urethral resistance algorithm (P < 0.01), AG number (P < 0.01) and maximum cystic capacity (P < 0.01). Of the men in the study, 10 (43.5%) remained in the same Schaer class with both methods and 18 (78.3%) in the same AG number area. Using the transurethral method, 12 (52.2%) men increased their Schaer class by one and 1 (4.3%) by two. There were also differences between the suprapubic and transurethral methods using the AG number: 4 (17.4%) men moved from a classification of equivocal to obstructed and 1 (4.3%) from unobstructed to equivocal. CONCLUSION: The differences between the techniques for measuring intravesical pressure alter the grading of obstruction determined by several of the commonly used classifications. An 8 F transurethral catheter significantly increases the likelihood of a diagnosis of bladder outlet obstruction when compared with the suprapubic method.

Aged↗

PubMed2006

Heterogeneous reactions of sulfur dioxide on typical mineral particles.

The heterogeneous reaction of SO2 on Al2O3, CaO, TiO2, MgO, FeOOH, Fe2O3, MnO2, and SiO2, as well as authentic aerosol sample, was investigated by using a White Cell coupled with in situ-FTIR and Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). Simultaneous observations of reactants and products were performed to obtain full information on the mechanism and kinetics of the reactions. SO2 was irreversibly adsorbed to form surface sulfite (SO3(2-)), bisulfite (HSO3(-)), and sulfate (SO4(2-)). The reactivity order of these particles is the following: FeOOH >Al2O3 > mixture > MgO > Fe2O3 > SiO2. Field-collected aerosol showed significant activity for the oxidation of SO2. The uptake coefficient of SO2 on Al2O3 with different acidity varied in the order of basic Al2O3 > neutral Al2O3 > acidic Al2O3. The surface-active oxygen and hydroxyl might be the key factors for the conversion of SO2 to SO4(2-). The faster reaction rate could be achieved with greater surface area on particles with the same mass. On the basis of the same surface area Fe2O3 could be most reactive in the reaction with SO2 compared with all other particles. The apparent rate constants were determined to be 1.35 x 10(-2) and 9.4 x 10(-3) for uptake on Al2O3 and MgO, respectively, which are the same as the results of other scientists.

Journal Article↗

PubMed2006

Dynamic behaviors of supersonic granular media under vertical vibration.

We present experimental study of vibrofluidized granular materials by high speed photography. Statistical results present the averaged dynamic behaviors of granular materials in one cycle, including the variations of height, velocity and mechanical energy of the center of mass. Furthermore, time-space distribution of granular temperature which corresponds to the random kinetic energy shows that a temperature peak forms in the compression period and propagates upward with a steepened front. The Mach number in the steepened front is found to be greater than unity, indicating a shock propagating in the supersonic granular media.

Journal Article↗

PubMed2006

Interior dynamics of subharmonious surface wave in an idealized bidimensional granular layer.

In this paper, high-speed photography was used to investigate the intrinsic dynamics of subharmonious surface wave in a vertical vibrated and idealized bidimensional granular layer. Using the high-speed photography, velocity fields of the granular layer at different stages through two cycles were obtained, which show the continuous particle motions during a cycle. From the velocity fields, a crystal structure in the wave-hollow was observed, which is reported for the first time. Furthermore, quantitative results of kinetic energy distribution in the layer were calculated, which shows temporal correspondence with the evolution of the wave pattern.

Journal Article↗

PubMed2006

RETRACTED: Investigation on photocatalytic degradation of ethyl violet dyestuff using visible light in the presence of ordinary rutile TiO2 catalyst doped with upconversion luminescence agent.

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. After careful investigations the editors have found that information in the paper is not reliable. Figure 4 appears similar to Figure 2 from another publication of the same authors in Dyes and Pigments 75 (2007) 335-343 https://doi.org/10.1016/j.dyepig.2006.06.007 which it is not describing the particles discussed in this Water Research paper. Although this article was published earlier than the Dyes and Pigments article, the Editor decided to retract this article given concerns about the reliability of the data.

Catalysis↗

PubMed2006

c-Myc downregulation: a critical molecular event in resveratrol-induced cell cycle arrest and apoptosis of human medulloblastoma cells.

The correlation of c-Myc expression with resveratrol-induced turnover of medulloblastoma cells was investigated in this study by checking (1) c-Myc expression in medulloblastoma tissues and cell lines (UW228-2 and UW228-3), (2) the in vitro effect of resveratrol on c-Myc expression and (3) the influences of c-Myc inhibition in cell growth and survival. Immunohistochemical staining of human medulloblastomas and noncancerous cerebellar tissues revealed that 8 out of 11 tumor tissues (72.7%) expressed c-Myc, in which 4 cases (50%) showed intensified nuclear labeling. RT-PCR, Western blotting, immunocytochemical and immunofluorescence stainings revealed c-Myc downregulation accompanied with growth suppression and apoptosis. Flow cytometry analysis showed S phase arrest in resveratrol-treated cell populations. Transfection of c-Myc directed antisense oligonucleotides to the cultured medulloblastoma cells could reduce c-Myc expression, inhibit cell growth and arrest the cell cycle at S phase. Our results thus for the first time demonstrate that c-Myc downregulation is a critical molecular event of resveratrol-mediated anti-medulloblastoma activity, which is closely associated with growth suppression, cell cycle arrest and apoptosis of medulloblastoma cells.

Antioxidants↗

PubMed2006

Combination of laparoscopic and open procedure in dismembered pyeloplasty: report of 51 cases.

BACKGROUND: Laparoscopic dismembered pyeloplasty with less trauma than open surgery is commonly performed for ureteropelvic junction obstruction despite a longer operating time and a long learning curve. We describe in this paper a new technique, which combines laparoscopic and open procedure in dismembered pyeloplasty, that we have developed in 51 patients and achieved excellent results. METHODS: The surgical procedure can be divided into two steps: laparoscopic dissection of the renal pelvis and proximal ureter transperitoneally; then accomplishing the pyeloplasty through the extended port incision above the ureteropelvic junction as in open surgery. RESULTS: All 51 operations were successful without conversion to open surgery. No intraoperative complications were observed. The operating time was 40 minutes to 90 minutes with an average of 57.5 minutes. The estimated blood loss was 15 ml to 30 ml with an average of 21.2 ml. Aberrant artery vessel and primary stricture as the cause of ureteropelvic junction obstruction was noted in 2 and 49 patients, respectively. Thirty-nine patients had fever to differing extents in the 4 days postoperation and no severe infection was observed. Four patients had urinary leakage with their drains being retained for 6 days, 6 days, 5 days or 8 days after the operation. The mean followup was 10.8 months (range 3 months to 36 months). The followup showed good results with symptom resolution in all the patients. Renal ultrasonography demonstrated that the average separation of the collecting systems decreased from preoperative 2.7 cm (range 2.0 cm to 4.7 cm) to postoperative 1.5 cm (range 1.0 cm to 2.3 cm). Excretory urography at 3 months postoperatively showed improved drainage. Of the 51 patients, 35 underwent two or more excretory urograms, demonstrating stable renal function, improved drainage and no evidence of recurrent obstruction. At the last followup visit, each patient was doing well. CONCLUSIONS: Combination of laparoscopic and open procedure in dismembered pyeloplasty offers a simpler, timesaving method in a minimally invasive fashion with low morbidity for patients with ureteropelvic junction obstruction. Ensuring quality of repair, the method provides a minimally invasive alternative with good results. It is worth future clinical application.

Adolescent↗