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Cavity Volume (cavity + volume)
Selected AbstractsPrediction of vapor,liquid equilibrium for polymer solutions based on the COSMO-SAC modelAICHE JOURNAL, Issue 10 2010Li Yang Abstract To extend the application of the COSMO-SAC model to phase-equilibrium calculations of polymer solutions, a new strategy for estimating the charge-density profile, the cavity volume and the cavity surface area of polymer molecules is proposed by finding reasonable parameters for the corresponding repeating structure units. The molecular parameters for polymers are obtained by summing up the corresponding COSMO calculated values of the repeating units calculated by the algorithms of DMol3 (a density functional theory) or MOPAC (a semi-empirical method). Combining with the COSMO-SAC model, the activities and equilibrium pressures for several typical polymer solutions are satisfactorily predicted indicating that the proposed method can be used for the prediction of vapor,liquid equilibrium of polymer solutions. It was also found that both DMol3 and MOPAC can be used though the results obtained from them are slightly different. The results in this paper show that the method proposed has the potential to predict other phase-equilibrium properties of polymer systems. © 2010 American Institute of Chemical Engineers AIChE J, 2010 [source] Group contribution prediction of surface charge density profiles for COSMO-RS(Ol)AICHE JOURNAL, Issue 12 2007Tiancheng Mu Abstract A new method for predicting the surface charge density distribution (, profile) and cavity volume of molecules based on group contributions was developed. The original , profiles used for the regression were obtained using Gaussian 03 B3LYP/6-311G(d,p). In total 1363 , profiles were used for the regression of group parameters. Group definitions are identical to those used previously for boiling point estimation. Original and estimated , profiles were used to predict activity coefficients at infinite dilution and VLE data of binary systems using the COSMO-RS(Ol) model. The results were compared with the experimental data stored in the Dortmund Data Bank. In many cases the results were of comparable accuracy. However, for a few compounds, poor results were obtained, in particular for conjugated components like nitrobenzenes. The method offers a fast and reliable generation of , profiles to be used with COSMO-RS(Ol) within its range of applicability. © 2007 American Institute of Chemical Engineers AIChE J, 2007 [source] Echocardiographic changes and risk factors for left ventricular hypertrophy in children and adolescents after renal transplantationPEDIATRIC TRANSPLANTATION, Issue 3 2004Amr A. El-Husseini Abstract:, Long-term consequences of cardiac alteration in children with chronic renal failure and after renal transplantation are largely unknown. In chronic uremia, cardiomyopathy manifests itself as systolic dysfunction, concentric left ventricular hypertrophy (LVH) or left ventricular dilatation. The correction of uremic state by renal transplantation leads to normalization of left ventricular contractility, regression of LVH and improvement of cavity volume and so dialysis patients with uremic cardiomyopathy would benefit from renal transplantation. We studied 73 patients, aged 17 yr or less, who underwent renal transplantation in our center. This cross-sectional study was performed 4.6 yr (median) after transplantation. Of the total, 48 were males and 25 were females. Transthoracic echocardiographic examination was performed for all cases. The effects of clinical, demographic, biochemical and therapeutic data on echocardiographic parameters were assessed. Multivariate analysis was used to assess the relation between the risk factors and the left ventricular muscle mass index. The most common echocardiographic abnormalities were the LVH (47.9%), left atrial enlargement (31.5%) and left ventricular dilatation and systolic dysfunction (13.7% for each). The pretransplant dialysis, arteriovenous fistula, acute rejection, cumulative steroid dose per square meter surface area, post-transplant hypertension, anemia and graft dysfunction were significant risk factors for LVH by univariate analysis. The significant factors by multivariate analysis were pretransplant dialysis, post-transplant hypertension and anemia. From this study we may conclude that LVH is a common problem among renal transplant children and adolescents. Early transplantation, control of hypertension and correction of anemia may be beneficial regarding left ventricular function and structure. [source] Nasal congestion index: A measure for nasal obstructionTHE LARYNGOSCOPE, Issue 8 2009Thomas Kjaergaard MD Abstract Objectives: The relationship between congestion of the nasal mucosa and subjective nasal obstruction remains poorly defined. Applying the novel Nasal Congestion Index (NCI), we compared subjective nasal obstruction with objective measures for reversible congestion of the nasal mucosa. Study Design: A total of 2,523 consecutive patients were included in this cross-sectional study. Eligible subjects were adults referred to the ENT department, Sørlandet Hospital, Kristiansand, Norway, for evaluation of chronic nasal or sleep-related complaints. Methods: Subjects underwent acoustic rhinometry (AR) and peak nasal inspiratory flow (PNIF) at baseline and after decongestion of the nasal mucosa. Based on these registrations, an NCI was calculated for minimal cross-sectional area (MCA), nasal cavity volume (NCV), and PNIF, and employed for quantification of reversible mucosal congestion. Subjective nasal obstruction was measured by nasal obstruction visual analogue scales (NO-VAS). Statistical analyses were based on ANOVA and multiple linear and logistic regression, adjusting for age, gender, body mass index, asthma, allergy, smoking history, and type of planned intervention. Results: Crude estimates indicated that the NCIs were significantly higher in subjects with severe complaints of nasal obstruction compared with subjects with lesser symptoms (P < .001). These associations were confirmed by linear and logistic regression analyses. NCI for MCA, NCV, and PNIF showed highly significant associations with subjective nasal obstruction (P < .001). Conclusions: We have clearly demonstrated an association between subjective nasal obstruction and reversible congestion of the nasal mucosa by employing the NCI. The measure has proven to be useful for evaluating patients with complaints of nasal obstruction. Laryngoscope, 2009 [source] 1352: Glass beads implantation in the scleral cavity during eviscerationACTA OPHTHALMOLOGICA, Issue 2010N ROSEN Purpose To review the background for developing the surgical modification of glass bead implantation in the scleral cavity during evisceration, to demonstrate the technique, and to highlight its indications, advantages and complications. Methods Personal experience is used to demonstrate the technique, its indications, advantages and complications. This includes the follow-up data of 17 patients who underwent evisceration with glass bead implantation during 1993-1996 and our experience from 164 eviscerations performed in our eye institute during the last 14 years. Results All patients achieved good cosmetic results with relatively good motility of the prosthesis. Complications included transient chemosis at the early postoperative period; three patients had local dehiscence of the wound, two patients developed a cyst in the socket and one patient was afflicted with thinning of the conjunctiva over the surgical wound. Conclusion The use of glass beads to fill the scleral cavity during evisceration has the advantage of an excellent fit in accordance with the scleral cavity volume, as well as ease of treatment in case of extrusion. The prosthesis movement is good because of its engagement with the scleral bulges caused by the glass beads. [source] Overexpression of Bcl-XL in human neural stem cells promotes graft survival and functional recovery following transplantation in spinal cord injuryJOURNAL OF NEUROSCIENCE RESEARCH, Issue 14 2009Seung I. Lee Abstract Transplantation of neural stem cells (NSCs) has shown promise for improving functional recovery after spinal cord injury (SCI). The inhospitable milieu of injured spinal cord, however, does not support survival of grafted NSCs, reducing therapeutic efficacy of transplantation. The present study sought to examine whether overexpression of antiapoptotic gene Bcl-XL in NSCs could promote graft survival and functional recovery following transplantation in rat contusive SCI model. A human NSC line (HB1.F3) was transduced with a retroviral vector encoding Bcl-XL to generate Bcl-XL -overexpressing NSCs (HB1.F3.Bcl-XL). Overexpression of Bcl-XL conferred resistance to staurosporine-mediated apoptosis. The number of HB1.F3.Bcl-XL cells was 1.5-fold higher at 2 weeks and 10-fold higher at 7 weeks posttransplantation than that of HB1.F3 cells. There was no decline in the number of HB1.F3.Bcl-XL cells between 2 and 7 weeks, indicating that Bcl-XL overexpression completely blocked cell death occurring between these two time points. Transplantation of HB1.F3.Bcl-XL cells improved locomotor scores and enhanced accuracy of hindlimb placement in a grid walk. Approximately 10% of surviving NSCs differentiated into oligodendrocytes. Surviving NSCs produced brain-derived neurotrophic factor (BDNF), and the level of BDNF was significantly increased only in the HB1.F3.Bcl-XL group. Transplantation of HB1.F3.Bcl-XL cells reduced cavity volumes and enhanced white matter sparing. Finally, HB1.F3.Bcl-XL grafts enhanced connectivity between the red nucleus and the spinal cord below the lesion. These results suggest that enhancing graft survival with antiapoptotic gene can potentiate therapeutic benefits of NSC-based therapy for SCI. © 2009 Wiley-Liss, Inc. [source] 4D retrospective black blood trueFISP imaging of mouse heartMAGNETIC RESONANCE IN MEDICINE, Issue 5 2009Sylvain Miraux Abstract The purpose of this study was to demonstrate the feasibility of steady-state True fast imaging with steady precession (TrueFISP) four-dimensional imaging of mouse heart at high resolution and its efficiency for cardiac volumetry. Three-dimensional cine-imaging of control and hypoxic mice was carried out at 4.7 T without magnetization preparation or ECG-triggering. The k -space lines were acquired with the TrueFISP sequence (pulse repetition time/echo time = 4/2 ms) in a repeated sequential manner. Retrospective reordering of raw data allowed the reconstruction of 10 three-dimensional images per cardiac cycle. The acquisition scheme used an alternating radiofrequency phase and sum-of-square reconstruction method. Black-blood three-dimensional images at around 200 ,m resolution were produced without banding artifact throughout the cardiac cycle. High contrast to noise made it possible to estimate cavity volumes during diastole and systole. Right and left ventricular stroke volume was significantly higher in hypoxic mice vs controls (20.2 ± 2 vs 15.1 ± 2; P < 0.05, 24.9 ± 2 vs 20.4 ± 2; P < 0.05, respectively). In conclusion, four-dimensional black-blood TrueFISP imaging in living mice is a method of choice to investigate cardiac abnormalities in mouse models. Magn Reson Med, 2009. © 2009 Wiley-Liss, Inc. [source] | ||||||||||