Dynamic heterogeneities, boson peak, and activation volume in glass-forming liquids

There are various arguments and models connecting the characteristic length associated with the boson peak vibrations ξ to the length scale of dynamical heterogeneity L(het). ξ is usually defined as the ratio of the transverse sound velocity to the boson peak frequency. Here we present pressure, temperature, and molecular weight dependencies of ξ, estimated using light scattering, in a few molecular and polymeric glass formers. These dependencies are compared with respective dependencies of the activation volume ΔV(#) in the same materials. Good agreement is found for the pressure and molecular weight dependencies of ξ and ΔV(#) measured at the glass transition temperature T(g). These results provide more evidence for a possible relationship between the sensitivity of structural relaxation to density (activation volume) and the heterogeneity volume. However, contrary to the expectations for L(het), ξ does not decrease with temperature above T(g) in most of the studied materials. The temperature dependence of ξ is compared to that of L(het) in glycerol and orthoterphenyl (OTP) estimated from literature data. The analysis shows a clear difference in the behavior of ξ(T) and ΔV(#)(T) at temperatures above T(g), although ΔV(#)(T)(1/3) and L(het)(T) have similar temperature dependence. Possible reasons for the observed difference are discussed.

The role of serum basic fibroblast growth factor, estradiol and urine basic fibroblast growth factor in differentiating infantile haemangiomas from vascular malformations

OBJECTIVE

To investigate the role of serum basic fibroblast growth factor (bFGF), estradiol (E2) and urine bFGF in differentiating infantile haemangiomas from vascular malformations.

METHOD

Between October 2007 and January 2009, 97 patients with haemangiomas and 25 patients with vascular malformations who had not been treated previously were included in this prospective study. Forty-eight patients with cleft lip and/or palate were selected as controls. The age of all subjects ranged from 1 to 30 months. The serum and urine levels of bFGF were determined by enzyme-linked immunosorbent assay (ELISA). The serum levels of E2 were examined via radioimmunoassay. All data were analysed with SPSS 11.5 software package.

RESULTS

The concentration of serum and urine bFGF was significantly different among the three groups (haemangiomas, vascular malformations and controls) (P = 0.027, P = 0.001). Significantly different urine bFGF levels were found in patients with proliferating and involuting haemangiomas (P = 0.04). The serum E2 levels were significantly higher in patients with haemangiomas than vascular malformations (P = 0.001) and controls (P = 0.001).

CONCLUSION

Serum bFGF and E2 as well as urine bFGF can be used to supplement the clinical diagnosis of congenital vascular anomalies. Urine bFGF combined with serum E2 may be the most potential markers for diagnosing haemangiomas and determining the proliferating stage of haemangiomas.

Application of a self-made swivel intravenous transfusion device in constructing allogenic small bowel transplantation rejection model in rats

BACKGROUND

Lacking a long-term continuous intravenous infusion device for experimental animals is the biggest obstacle to constructing an allogenic small bowel transplantation rejection model.

OBJECTIVE

To establish a rat heterotopic small bowel transplantation model with the use of a swivel device for intravenous transfusion.

METHODS

The randomized block design of controlled observations included 90 inbred male F344/NCrl BR rats as donors and 90 LEW/Crl rats as recipients. On the basis of body weight, the rats were divided into three groups each with 30 pairs of rats. Group 1, the control group, underwent small bowel transplantation. Group 2, the transfusion group, received small bowel transplantation and continuous infusion of parenteral nutrient solution. Group 3, the tacrolimus (FK506) treatment group, received small bowel transplantation, continuous infusion of parenteral nutrient solution, and intravenous injection of FK506. The general status and survival time of transplanted rats were observed for 5 weeks.

RESULTS

The operative success rate was 100%. The survival rate was 83.3% (25/30) in the control group; and 96.7% (58/60) in groups 2 and 3 (P = .039). The mean survival time of the FK506 group was 22.1 +/- 13.4 days, which was significantly higher than that in the transfusion group (10.4 +/- 2.9 days, P = .023).

CONCLUSION

The simple, practical swivel intravenous infusion device provided treatment for more than 30 days, a useful tool for heterotopic segmental small bowel transplantation.

Laparoscopic sacral colpopexy for uterine prolapse with prolene mesh

OBJECTIVE

To analyze the clinical effects of laparoscopic sacral colpopexy using prolene mesh for patients with pelvic organ prolapse.

METHODS

Laparoscopic placement of prolene mesh in the rectovaginal septum and veslcovaginal septum of 42 women with uterine prolapse with bladder and rectum prolapse. One mesh was fixed to the round ligaments and another to the periosteum of the sacral vertebrae. Operation time, blood loss, complication rate and follow-up surgery results were recorded monthly and analyzed according to the POP-Q system. The uterus was preserved in all cases.

RESULTS

The mean operating time was 92 +/- 12 min and the mean blood loss during surgery was 98 +/- 11 ml. Postoperatively, both prolapse and symptoms were highly significantly improved (p < 0.001) according to the pelvic organ prolapse quantification (POP-Q) system.

CONCLUSIONS

Laparoscopic sacral colpopexy for uterine prolapse using prolene mesh is a minimally invasive and effective new technique that offers a chance for patients who desire to preserve their uterus.

Association between enamel hypoplasia and dental caries in primary second molars: a cohort study

The purpose of this study was to assess the longitudinal relationships between enamel hypoplasia and caries experience of primary second molars. The study sample was 491 subjects who received dental examinations at both age 5 and 9 by the calibrated examiners. Four primary second molars (n = 1,892) were scored for the presence of enamel hypoplasia for each participant. Caries presence and number of decayed and filled surfaces (dfs) were determined at age 5 and 9. The relationships between enamel hypoplasia and caries experience were assessed. Among primary second molars, 3.9% of children and 1.7% of primary second molars had enamel hypoplasia. At age 5, 36.8% of children with hypoplasia had caries, while 16.9% of children without enamel hypoplasia had caries. At age 9, the corresponding numbers were 52.6% for children with hypoplasia and 34.5% for children without hypoplasia, respectively. At the tooth level, for age 5, 28.1% of teeth with hypoplasia had caries (mean dfs = 0.40), and 7.6% of teeth without hypoplasia had caries (mean dfs = 0.11). At age 9, the corresponding numbers were 41.9% (mean dfs = 0.76) for teeth with hypoplasia and 18.3% (mean dfs = 0.34) for teeth without hypoplasia. In multivariable logistic regression analyses, teeth of subjects with enamel hypoplasia had a significantly higher risk for caries at age 5 and 9 after controlling for other risk factors. Enamel hypoplasia appears to be a significant risk factor for caries and should be considered in caries risk assessment.

Prediction of the prognosis of patients with acute-on-chronic hepatitis B liver failure using the model for end-stage liver disease scoring system and a novel logistic regression model

The objective of this study was to determine the predictive value of the model for end-stage liver disease (MELD) scoring system in patients with acute-on-chronic hepatitis B liver failure (ACLF-HBV), and to establish a new model for predicting the prognosis of ACLF-HBV. A total of 204 adult patients with ACLF-HBV were retrospectively recruited between July 1, 2002 and December 31, 2004. The MELD scores were calculated according to the widely accepted formula. The 3-month mortality was calculated. The validity of the MELD model was determined by means of the concordance (c) statistic. Clinical data and biochemical values were included in the multivariate logistic regression analysis based on which the regression model for predicting prognosis was established. The receiver-operating characteristic curves were drawn for the MELD scoring system and the new regression model and the areas under the curves (AUC) were compared by the z-test. The 3-month mortality rate was 57.8%. The mean MELD score for the patients who died was significantly greater than those who survived beyond 3 months (28.7 vs 22.4, P = 0.003). The concordance (c) statistic (equivalent to the AUC) for the MELD scoring system predicting 3-month mortality was 0.709 (SE = 0.036, P < 0.001, 95% confidence interval 0.638-0.780). The independent factors predicting prognosis were hepatorenal syndrome (P < 0.001), liver cirrhosis (P = 0.009), HBeAg (P = 0.013), albumin (P = 0.028) and prothrombin activity (P = 0.011) as identified in multivariate logistic regression analysis. The regression model that was constructed by the logistic regression analysis produced a greater prognostic value (c = 0.891) than the MELD scoring system (z = 4.333, P < 0.001). The MELD scoring system is a promising and useful predictor for 3-month mortality of ACLF-HBV patients. Hepatorenal syndrome, liver cirrhosis, HBeAg, albumin and prothrombin activity are independent factors affecting the 3-month mortality. The newly established logistic regression model appears to be superior to the MELD scoring system in predicting 3-month mortality in patients with ACLF-HBV.