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MDI
Selected AbstractsHow to optimize patch testing with diphenylmethane diisocyanateCONTACT DERMATITIS, Issue 3 2007Malin Frick-Engfeldt We have previously shown that patch test preparations of polymeric diphenylmethane diisocyanate (PMDI) are more stable than preparations of diphenylmethane-4,4'-diisocyanate (4,4'-MDI). This study was conducted to (i) investigate whether PMDIs yield as many positive reactions as 4,4'-MDI, (ii) study concurrent reactions to 4,4'-MDI and 4,4'-diaminodiphenylmethane (4,4'-MDA), and (iii) follow the course of positive reactions during 4 weeks. It was shown that PMDIs detect as many positive reactions as 4,4'-MDI. Thus, they are better patch test agents being more stable than preparations of 4,4'-MDI. We recommend that PMDIs with a monomer content of at least 35% is used in 2.0% petrolatum (pet.) (i.e. monomer patch test concentration approximately 0.7%). It was shown that reactions to 4,4'-MDI and PMDIs appear late and we recommend readings on both day (D) 3/4 and D7. 4,4'-MDA was shown to be a good marker for 4,4'-MDI and patch testing with 4,4'-MDA in 0.25% pet. can be used instead of PMDI. Concomitant reactions to 4,4'-MDI and 4,4'-MDA are probably not caused by conversion of 4,4'-MDI into 4,4'-MDA by reaction with water. Another explanation is a path of reactions leading to ureas and MDI conjugates with skin constituents, which are hydrolysed into 4,4'-MDA. This complex process depends upon several factors and might explain why positive MDI reactions appear after D7. [source] Developmental assessment of preterm infants at 2 years: validity of parent reportsDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 1 2008Samantha Johnson PhD CPsychol Parental questionnaires are inexpensive alternatives to standardized testing for outcome measurement. The Parent Report of Children's Abilities has previously been revised (PARCA-R) and validated for use with very-preterm infants at 2 years of age. This study revalidated the PARCA-R for assessing cognition in a larger and more inclusive sample of preterm infants. One hundred and sixty-four children (82 males, 82 females) of <32 weeks' gestation (median 29wks, interquartile range [IQR] 28-30wks); and median birthweight 1200g (IQR 925-1463g) were evaluated using the Mental Development Index (MDI) of the Bayley Scales of Infant Development - 2nd edition (BSID-II) at 2 years' corrected age. Parents completed the PARCA-R questionnaire. Significant correlations between PARCA-R Parent Report Composite (PRC) scores and MDI scores (r=0.77, 95% confidence interval [CI] 0.69-0.82, p<0.01) demonstrated concurrent validity. A receiver operating characteristic-determined PRC cut-off of <44 had optimal discriminatory power (area under curve 0.92) for identifying MDI <70, with 85% sensitivity (95% CI 0.58-0.96), 87% specificity (95% CI 0.81-0.92), 98% negative predictive value (95% CI 0.95-1), and 37% positive predictive value (95% CI 0.22-0.54). The PARCA-R has good concurrent validity and diagnostic utility for identifying cognitive delay in very-preterm infants at 2 years of age. It is useful for outcome measurement, developmental screening, and facilitating parental involvement at folow-up. [source] Inhaled insulin as adjunctive therapy in subjects with type 2 diabetes failing oral agents: a controlled proof-of-concept studyDIABETES OBESITY & METABOLISM, Issue 5 2006M. Hausmann Aim:, This controlled proof-of-concept study investigated inhaled insulin (INH) as adjunctive therapy to existing oral antidiabetic agents in subjects with type 2 diabetes. Methods:, Twenty-four subjects with type 2 diabetes [19 men and 5 women, 56.1 ± 6.6 years, body mass index 32.7 ± 4.2 kg/m2, glycosylated haemoglobin (HbA1c) 8.4 ± 0.8% (mean ± s.d.)] inadequately controlled by metformin and/or sulfonylureas were randomized to receive additional therapy with either INH administered preprandially using a metered-dose inhaler (MDI), or insulin glargine (GLA) injected subcutaneously at bedtime for 4 weeks. Both inhaled and injected insulin doses were titrated to predefined blood glucose (BG) targets. Results:, INH and GLA improved metabolic control to a similar extent. Mean daily BG decreased by 2.8 mmol/l in the INH group (p < 0.001) and by 2.4 mmol/l in the GLA group (p < 0.001). Accordingly, fasting BG (,2.7 vs. ,3.6 mmol/l for INH vs. GLA), preprandial- and 2-h postprandial BG, HbA1c (,1.23 vs. ,1.05%), body weight (,1.9 vs. ,2.3 kg) and serum fructosamine were similarly and significantly reduced in both groups (p < 0.05). Triglycerides decreased significantly with INH (,1.15 ,mol/l; p < 0.001) but not with GLA [,0.52 ,mol/l; not significant (NS)]. Incidence rates of adverse events did not differ significantly, and there were no indications of respiratory tract irritation. Conclusions:, In subjects with type 2 diabetes inadequately controlled by oral agents, preprandial administration of INH delivered by a MDI provided a comparable metabolic control to bedtime GLA and did not show any safety concerns during a 4-week treatment. These results warrant a more extensive investigation of preprandial treatment with INH in longer term studies. [source] Continuous subcutaneous insulin infusion (CSII) 30 years later: still the best option for insulin therapyDIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 2 2009Daniela Bruttomesso Abstract Thirty years after its introduction, the use of continuous subcutaneous insulin infusion (CSII) keeps increasing, especially among children and adolescents. The technique, when used properly, is safe and effective. Compared with traditional NPH-based multiple daily injections (MDI), CSII provides a small but clinically important reduction of HbA1c levels, diminishes blood glucose variability, decreases severe hypoglycaemic episodes and offers a better way to cope with the dawn phenomenon. Insulin analogues have improved the treatment of diabetes, eroding part of the place previously occupied by CSII, but CSII still remains the first option for patients experiencing severe hypoglycaemic episodes, high HbA1c values or marked glucose variability while being treated with optimized MDI. Furthermore CSII is better than MDI considering the effects on quality of life and the possibility to adjust insulin administration according to physical activity or food intake. CSII may be limited by cost. Present estimates suggest that CSII may be cost-effective just for patients experiencing a marked improvement in HbA1c or a decrease in severe hypoglycaemic episodes, but the effects on quality of life are difficult to measure. CSII does not merely imply wearing an external device; it requires a multidisciplinary team, intensive patient education and continuous follow up. Copyright © 2009 John Wiley & Sons, Ltd. [source] Diabetes management in the new millennium using insulin pump therapyDIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue S1 2002Bruce W. Bode Abstract Current goals of therapy of type 1 and 2 diabetes are to achieve near normal glycemia, minimize the risk of severe hypoglycemia, limit excessive weight gain, improve quality of life and delay or prevent late vascular complications. As discussed in this review, insulin pump or continuous subcutaneous insulin infusion (CSII) therapy provides a treatment option that can dramatically aid in achieving all of these goals. In comparison to multiple daily injections (MDI), CSII uses only rapid-acting insulin, provides greater flexibility in timing of meals and snacks, has programmable basal rates to optimize overnight glycemic control, can reduce the risk of exercise-induced hypoglycemia, and enhances patients' ability to control their own diabetes. Most important, in adults and adolescents with type 1 diabetes, CSII has been shown to lower HbA1c levels, reduce the frequency of severe hypoglycemia and limit excessive weight gain versus MDI without increasing the risk of diabetic ketoacidosis. Similarly positive results are being seen with CSII in adults with type 2 diabetes. The effectiveness of CSII and improvements in pump technology have fueled a dramatic increase in the use of this therapy. Practical guidelines are presented for selection of patients, initiation of treatment, patient education, follow-up assessments and troubleshooting. The recent introduction of methods for continuous glucose monitoring provides a new means to optimize the basal and bolus capabilities of CSII and offers the hope of the development of a feedback-controlled artificial pancreas. Copyright © 2002 John Wiley & Sons, Ltd. [source] Severe hypoglycaemia and glycaemic control in Type 1 diabetes: meta-analysis of multiple daily insulin injections compared with continuous subcutaneous insulin infusionDIABETIC MEDICINE, Issue 7 2008J. C. Pickup Abstract Aims Continuous subcutaneous insulin infusion (CSII) is a recommended treatment for reducing severe hypoglycaemia in Type 1 diabetes, but the change in hypoglycaemia compared with multiple daily insulin injections (MDI) is unclear. We therefore conducted a meta-analysis comparing severe hypoglycaemia and glycaemic control during CSII and MDI. Methods Databases and literature (1996,2006) were searched for randomized controlled trials (RCTs) and before/after studies of , 6 months' duration CSII and with severe hypoglycaemia frequency > 10 episodes/100 patient years on MDI. Results In 22 studies (21 reports), severe hypoglycaemia during MDI was related to diabetes duration (P = 0.038) and was greater in adults than children (100 vs. 36 events/100 patient years, P = 0.036). Severe hypoglycaemia was reduced during CSII compared with MDI, with a rate ratio of 2.89 (95% CI 1.45 to 5.76) for RCTs and 4.34 (2.87 to 6.56) for before/after studies [rate ratio 4.19 (2.86 to 6.13) for all studies]. The reduction was greatest in those with the highest initial severe hypoglycaemia rates on MDI (P < 0.001). The mean difference in glycated haemoglobin (HbA1c) between treatments was less for RCTs [0.21% (0.13,0.30%)] than in before/after studies [0.72% (0.55,0.90%)] but strongly related to the initial HbA1c on MDI (P < 0.001). Conclusions The severe hypoglycaemia rate in Type 1 diabetes was markedly less during CSII than MDI, with the greatest reduction in those with most severe hypoglycaemia on MDI and those with the longest duration of diabetes. The biggest improvement in HbA1c was in those with the highest HbA1c on MDI. [source] Comparison of continuous subcutaneous insulin infusion (CSII) and multiple daily injections (MDI) in paediatric Type 1 diabetes: a multicentre matched-pair cohort analysis over 3 yearsDIABETIC MEDICINE, Issue 1 2008B. I. Jakisch Abstract Aims To conduct a multicentre, matched-pair cohort analysis comparing glycaemic control and adverse events of continuous subcutaneous insulin infusion (CSII) with multiple daily injections (MDI) in paediatric patients. Methods Using standardized computer-based prospective documentation, HbA1c, insulin dose, body mass index,standard deviation score (BMI,SDS), rate of hypoglycaemia, rate of diabetic ketoacidosis (DKA) and intensity of care were analysed in 434 matched pairs during a follow-up period of 3 years after initiation of MDI or CSII. Results HbA1c was significantly lower in the CSII group during the first year of new regimen (CSII 7.5 ± 0.05 vs. MDI 7.7 ± 0.06; P < 0.05), but rose to the same level as in the MDI group during year 3. Insulin requirement remained significantly lower in the CSII group. The BMI,SDS increased in both study groups, with no significant difference. The rate of severe hypoglycaemia decreased significantly after the change of regimen (CSII 17.87 ± 2.85 vs. MDI 25.14 ± 3.79; P < 0.05) and during year 3 of the regimen, particularly when compared with baseline (,21% vs. ,16%). The rate of DKA was lower at baseline in the CSII group and remained significantly lower over all 3 years. Intensity of care was the same in both subsets. Conclusions Employing a large cohort, this matched-pair analysis has demonstrated over a 3-year study period that CSII is a safe form of intensive insulin therapy with similar glycaemic effects, but with significantly reduced rates of hypoglycaemia and DKA and a lower insulin requirement when compared with MDI. [source] Insulin pump therapy vs. multiple daily injections in obese Type 2 diabetic patientsDIABETIC MEDICINE, Issue 8 2005J. Wainstein Abstract Aims To compare the efficacy of insulin pump treatment with multiple daily injections in the treatment of poorly controlled obese Type 2 diabetic patients already receiving two or more daily injections of insulin plus metformin. Methods Forty obese Type 2 diabetic subjects (using insulin) were randomized to treatment with continuous subcutaneous infusion pump (CSII) (Minimed®) or multiple daily insulin injections (MDI). At the end of the first 18-week treatment period, patients underwent a 12-week washout period during which they were treated with MDI plus metformin. They were then crossed-over to the other treatment for an 18-week follow-up period. Patients performed 4-point daily self blood-glucose monitoring (SBGM) on a regular basis and 7-point monitoring prior to visits 2, 8, 10 and 16. A subset of patients underwent continuous glucose monitoring using the Minimed® continuous glucose monitoring system (CGMS) at visits 2, 8, 10 and 16. A standard meal test was performed in which serum glucose was tested at fasting and once each hour for 6 h following a test meal. Glucose levels were plotted against time and the area under the curve (AUC) was calculated. HbA1c, weight, daily insulin dose and hypoglycaemic episodes were recorded. Results In obese Type 2 diabetic patients already treated with insulin, treatment with CSII significantly reduced HbA1c levels compared with treatment with MDI. An additional CSII treatment benefit was demonstrated by reduced meal-test glucose AUC. Initial reduction of daily insulin requirement observed in CSII-treated subjects during the first treatment period was attributable to a period effect and did not persist over time. Conclusions In the intent-to-treat analysis, CSII appeared to be superior to MDI in reducing HbA1c and glucose AUC values without significant change in weight or insulin dose in obese, uncontrolled, insulin-treated Type 2 diabetic subjects. [source] The cost-effectiveness of continuous subcutaneous insulin infusion compared with multiple daily injections for the management of diabetesDIABETIC MEDICINE, Issue 7 2003P. Scuffham Abstract Aims To estimate the cost effectiveness of continuous subcutaneous insulin infusion (CSII) compared with multiple daily injections (MDI) for patients using insulin pumps. Methods We constructed a Markov model to estimate the costs and outcomes for patients with insulin-dependent diabetes (IDDM) treated with CSII using an insulin pump compared with MDI. Key parameters were obtained from the published scientific literature. The primary outcome was quality-adjusted life years (QALYs). Monte Carlo simulations were undertaken for 10 000 hypothetical patients over 8 years of monthly cycles (the expected life of a pump). Results Over an 8-year period an average patient could expect to gain 0.48 [standard deviation (sd) 0.20] QALYs using CSII compared with MDI. The additional cost over 8 years for this gain was £5462 (sd£897). The incremental cost per QALY was £11 461 (sd£3656). CSII was most cost-effective in patients who had more than two severe hypoglycaemic events per year and who required admission to hospital at least once every year. Cases where CSII might be not economically viable are cases where diabetes is well controlled with few severe hypoglycaemic events. Results were most sensitive to the number of hypoglycaemic events per patient and the utility weights used to estimate QALYs. Conclusion CSII is a worthwhile investment when targeted to those who might benefit most. Diabet. Med. 20, 586,593 (2003) [source] Recent advances in treatment of youth with Type 1 diabetes: better care through technologyDIABETIC MEDICINE, Issue 11 2001W. V. Tamborlane Abstract While treatment of Type 1 diabetes mellitus (T1DM) in children and adolescents is especially difficult, recent technological advances have provided new therapeutic options to clinicians and patients. The urgency to achieve strict diabetes control and the introduction of new and improved insulin pumps have been accompanied by a marked increase in use of continuous subcutaneous insulin infusion (CSII) therapy in youth with diabetes. Results of clinical outcome studies indicate that CSII provides a safe and effective alternative to multiple daily injection (MDI) therapy, even when employed in a regular clinic setting in a large number of children. The safety and efficacy of CSII is further enhanced by the introduction of lispro and aspart insulin. The sharper peaks and shorter duration of action of these very rapid-acting insulin analogues provides a means to achieve better control of post-prandial hyperglycaemia with less late post-prandial and nocturnal hypoglycaemia. Glargine insulin, a soluble and essentially peakless long-acting insulin analogue, may provide a better basal insulin for MDI regimens, but there are limited published data with this agent in children with T1DM. A number of systems for pulmonary delivery of insulin are in development and preliminary results of Phase III studies have been promising. Like CSII, inhaled insulin allows the child to take bolus insulin doses before each meal without having to take a premeal injection. A major obstacle to effective treatment is that self-monitoring of three to four blood glucose levels a day often misses the marked glycaemic excursions that characterize T1DM in young patients. On the other hand, new continuous glucose sensing systems provide a wealth of data that can be used to optimize basal and bolus therapy, regardless of how insulin is administered. Even more important, we may finally be at the threshold of development of a practically applicable artificial pancreas. Diabet. Med. 18, 864,870 (2001) [source] Assessing burn severity and comparing soil water repellency, Hayman Fire, ColoradoHYDROLOGICAL PROCESSES, Issue 1 2006Sarah A. Lewis Abstract An important element of evaluating a large wildfire is to assess its effects on the soil in order to predict the potential watershed response. After the 55 000 ha Hayman Fire on the Colorado Front Range, 24 soil and vegetation variables were measured to determine the key variables that could be used for a rapid field assessment of burn severity. The percentage of exposed mineral soil and litter cover proved to be the best predictors of burn severity in this environment. Two burn severity classifications, one from a statistical classification tree and the other a Burned Area Emergency Response (BAER) burn severity map, were compared with measured ,ground truth' burn severity at 183 plots and were 56% and 69% accurate, respectively. This study also compared water repellency measurements made with the water drop penetration time (WDPT) test and a mini-disk infiltrometer (MDI) test. At the soil surface, the moderate and highly burned sites had the strongest water repellency, yet were not significantly different from each other. Areas burned at moderate severity had 1·5 times more plots that were strongly water repellent at the surface than the areas burned at high severity. However, the high severity plots most likely had a deeper water repellent layer that was not detected with our surface tests. The WDPT and MDI values had an overall correlation of r = ,0·64(p < 0·0001) and appeared to be compatible methods for assessing soil water repellency in the field. Both tests represent point measurements of a soil characteristic that has large spatial variability; hence, results from both tests reflect that variability, accounting for much of the remaining variance. The MDI is easier to use, takes about 1 min to assess a strongly water repellent soil and provides two indicators of water repellency: the time to start of infiltration and a relative infiltration rate. Copyright © 2005 John Wiley & Sons, Ltd. [source] Predicting Individual Differences in Recall by Infants Born Preterm and Full TermINFANCY, Issue 1 2006Carol L. Cheatham A heterogeneous sample of infants with preterm histories and infants born full term participated in a study of declarative memory and rate of encoding, as measured in an imitation task and an examining task, respectively. Here we report the comparisons of the performances of infants born very preterm (27,34 weeks gestation) and moderately preterm (35,37 weeks gestation) to infants born full term (38,41 weeks gestation) and tested at 12 months corrected age (from due date). Lower levels of recall were seen among the infants born very preterm. Rate of encoding, weeks gestation, and score on the Mental Development Index (MDI) of the Bayley Scales of Infant Development were tested as possible sources of individual differences in recall. Rate of encoding and MDI predicted delayed ordered recall. Implications for early detection of cognitive difficulties in children with preterm histories are discussed. [source] An adaptive clinical Type 1 diabetes control protocol to optimize conventional self-monitoring blood glucose and multiple daily-injection therapyINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 5 2009Xing-Wei Wong Abstract The objective of this study was to develop a safe, robust and effective protocol for the clinical control of Type 1 diabetes using conventional self-monitoring blood glucose (SMBG) measurements, and multiple daily injection (MDI) with insulin analogues. A virtual patient method is used to develop an in silico simulation tool for Type 1 diabetes using data from a Type 1 diabetes patient cohort (n=40) . The tool is used to test two prandial insulin protocols, an adaptive protocol (AC) and a conventional intensive insulin therapy (IIT) protocol (CC) against results from a representative control cohort as a function of SMBG frequency. With the prandial protocols, optimal and suboptimal basal insulin replacement using a clinically validated, forced-titration regimen is also evaluated. A Monte Carlo (MC) analysis using variability and error distributions derived from the clinical and physiological literature is used to test efficacy and robustness. MC analysis is performed for over 1 400 000 simulated patient hours. All results are compared with control data from which the virtual patients were derived. In conditions of suboptimal basal insulin replacement, the AC protocol significantly decreases HbA1c for SMBG frequencies ,6/day compared with controls and the CC protocol. With optimal basal insulin, mild and severe hypoglycaemia is reduced by 86,100% over controls for all SMBG frequencies. Control with the CC protocol and suboptimal basal insulin replacement saturates at an SMBG frequency of 6/day. The forced-titration regimen requires a minimum SMBG frequency of 6/day to prevent increased hypoglycaemia. Overaggressive basal dose titration with the CC protocol at lower SMBG frequencies is likely caused by uncorrected postprandial hyperglycaemia from the previous night. From the MC analysis, a defined peak in control is achieved at an SMBG frequency of 8/day. However, 90% of the cohort meets American Diabetes Association recommended HbA1c with just 2 measurements a day. A further 7.5% requires 4 measurements a day and only 2.5% (1 patient) required 6 measurements a day. In safety, the AC protocol is the most robust to applied MC error. Over all SMBG frequencies, the median for severe hypoglycaemia increases from 0 to 0.12% and for mild hypoglycaemia by 0,5.19% compared with the unrealistic no error simulation. While statistically significant, these figures are still very low and the distributions are well below those of the controls group. An adaptive control protocol for Type 1 diabetes is tested in silico under conditions of realistic variability and error. The adaptive (AC) protocol is effective and safe compared with conventional IIT (CC) and controls. As the fear of hypoglycaemia is a large psychological barrier to appropriate glycaemic control, adaptive model-based protocols may represent the next evolution of IIT to deliver increased glycaemic control with increased safety over conventional methods, while still utilizing the most commonly used forms of intervention (SMBG and MDI). The use of MC methods to evaluate them provides a relevant robustness test that is not considered in the no error analyses of most other studies. Copyright © 2008 John Wiley & Sons, Ltd. [source] Acrylonitrile,butadiene rubber/reclaimed rubber,nylon fiber compositeADVANCES IN POLYMER TECHNOLOGY, Issue 4 2001T. D. Sreeja The effect of diphenylmethane diisocyanate (MDI),polyethyleneglycol (PEG) resin on the cure characteristics and mechanical properties of nitrile rubber/whole tyre reclaim,short nylon fiber composite,was studied. At a constant loading of 5 phr, the resin composition was varied. The minimum torque and (maximum , minimum) torque increased with isocyanate concentration. Scorch time and cure time showed a reduction on introduction of bonding agent. Properties like tensile strength, tear strength, and abrasion resistance increased with increase in MDI/PEG ratio, and these properties are higher in the longitudinal direction of fiber orientation. Compression set increased with isocyanate concentration and the resilience remain unchanged. © 2001 John Wiley & Sons, Inc. Adv Polym Techn 20: 281,288, 2001 [source] Compatibilization method applied to the chitosan-acid poly(L -lactide) solutionJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010Nugraha Edhi Suyatma Abstract We are testing the compatibilization of the chitosan/PLA blends by addition of diisocyanate and at studying the effect of several MDI concentrations (0.5 and 2.5% of the global blend mass, w/w). To evaluate the MDI efficiency as a compatibilizer of chitosan/PLA blends, we worked with the following methods: IRTF spectra with higher peak at 1558 cm,1 is due to the NH bonds that exist in urea and urethane, thermal properties shows that the temperature of the endothermic peaks of the chitosan/PLA blends with MDI is very close to the temperature of pure chitosane and SEM micrography shows that MDI addition decreases the PLA particles size in the chitosan mixture; they also comply with the compatibilization theory. After that the mechanical properties have been characterized: we can notice that the MDI compatibilized chitosan/PLA blends have a higher Young's modulus than the noncompatibilized blends. we are showed that the use of 0.5% MDI is not enough sufficient to obtain a compatibilization, because a part of the MDI can be consumed by water. The addition of MDI increases the performance of the mechanical properties of the blends. Therefore, with this compatibilization, we could obtain some chitosan/PLA blends that would be water-resistant and that would also keep their mechanical properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Synthesis and characterization of new polyurethane based on polycaprolactoneJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010El Miloud Maafi Abstract Different polyurethane (PU) were synthesized from ,-polycaprolactone diol, 4,4,-diphenyl methane diisocyanate (MDI) and bis(2-hydroxyethyl)terephthalate (BHET), using a two-step method and a one-step method providing regular and random distributions of starting monomers in the PU chains. Even with an identical molar monomer composition, the properties of obtained PU are different depending on the method of synthesis. The structure of PU was characterized by 1H and 13C-NMR and Fourier transform infrared spectroscopy (FTIR). The thermomechanical properties of synthesized PU were also studied demonstrating the influence of aromatic ring in the macromolecular chain. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Moisture-cured polyurethane/polysiloxane copolymers: Effects of the structure of polyester diol and NCO/OH ratioJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008Hongmei Jiang Abstract Moisture-cured polyurethane is one of the commercially important polymers, which is widely used in sealants, coatings, and reactive hot-melt adhesives. A series of moisture-cured polyurethane/polysiloxane (PUSR) copolymers were successfully prepared using a two-step solution polymerization procedure. Both amine-terminated polysiloxane (PDMS) and polyester diol were together used as mixed soft segments to react with 4,4,-diphenlymethane diisocyanate (MDI), and the alkoxysilane was used as end-capping agents. The effects of structure variation of building blocks such as the polyester diol structure and NCO/OH ratio on the properties and morphology of PUSR copolymers were studied. The tensile properties, dielectric behavior, thermal stability, surface, and water-repellency properties were investigated. The results showed that the properties and morphology of PUSR copolymers were greatly affected by the variations in molecular architecture. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Idiopathic Left Ventricular Arrhythmias Originating Adjacent to the Left Aortic Sinus of Valsalva: Electrophysiological Rationale for the Surface ElectrocardiogramJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 2 2010TAKUMI YAMADA M.D. IVT Arising Adjacent to the Left Sinus of Valsalva.Background: Idiopathic ventricular arrhythmias (VAs) may be amenable to catheter ablation within or adjacent to the left sinus of Valsalva (LSOV). However, features that discriminate these sites have not been defined. The purpose of this study was to determine the electrocardiographic and electrophysiological features of VAs originating within or adjacent to the LSOV. Methods and Results: We studied 48 consecutive patients undergoing successful catheter ablation of idiopathic VAs originating from the left coronary cusp (LCC, n = 29), aortomitral continuity (AMC, n = 10) and great cardiac vein or anterior interventricular cardiac vein (Epi, n = 9). A small r wave, or rarely an R wave, was typically observed in lead I during the VAs and pacing in these regions. An S wave in lead V5 or V6 occurred significantly more often during both the VAs and pacing from the AMC than during that from the LCC and Epi (p < 0.05 to 0.0001). For discriminating whether VA origins can be ablated endocardially or epicardially, the maximum deflection index (MDI = the shortest time to the maximum deflection in any precordial lead/QRS duration) was reliable for VAs arising from the AMC (100%), but was less reliable for LCC (73%) and Epi (67%) VAs. In 3 (33%) of the Epi VAs, the site of an excellent pace map was located transmurally opposite to the successful ablation site (LCC = 1 and AMC = 2). Conclusions: The MDI has limited value for discriminating endocardial from epicardial VA origins in sites adjacent to the LSOV probably due to preferential conduction, intramural VA origins or myocardium in contact with the LCC. (J Cardiovasc Electrophysiol, Vol. 21, pp. 170-176, February 2010) [source] Effect of an early intervention programme on low birthweight infants with cerebral injuriesJOURNAL OF PAEDIATRICS AND CHILD HEALTH, Issue 12 2004S Ohgi Objective: To determine the effect of an early intervention programme (EIP) on low birthweight infants with cerebral injuries. Methods: Subjects were 23 high-risk low birthweight infants (periventricular leukomalacia 15, intraventricular haemorrhage 5, both 3) receiving care in the neonatal intensive care unit (NICU) at Nagasaki University Hospital. Subjects were randomly assigned to the EIP group (n = 12) or the control group (n = 11). Participants in the EIP group received a Neonatal Behavioral Assessment scale (NBAS)-based intervention combined with developmental support designed to enhance the infants' development and the quality of the parent,infant relationship. The control group received routine medical nursing care without the EIP. The EIP began prior to discharge from the NICU and lasted until 6 months of corrected age. All children were examined on the NBAS preintervention and again at 44 weeks postconceptional age. Maternal anxiety status (STAI) and maternal feelings of confidence in dealing with her baby (LCC) were measured pre and postintervention. Mental and motor development was assessed postintervention using the Bayley Scale of Infant Development. Results: Orientation and State Regulation of infant behavioural profiles, the STAI and LCC scores significantly improved in the EIP group (mean difference (95% CI): Orientation 0.7 (0.4, 1.1), State Regulation 0.9 (0.3, 1.5), STAI ,5.5 (, 9.1, ,1.9, LCC 5.3 (4.2, 6.5)), but not in the control group. Bayley mental developmental index (MDI) score in the EIP group was higher than in the control group, but there was no significant difference between the two groups (mean difference (95% CI): MDI 8.5 (, 0.8, 17.8), PDI 6.7 (, 1.9, 15.4)). Conclusion: The EIP has beneficial effects on neonatal neurobehavioural development and maternal mental health of low birthweight infants with cerebral injuries. This evidence suggests that short-term changes in maternal mental health and infant neurobehaviour promoted by an EIP may serve to initiate a positive interaction between parents and infants. [source] Predictors of neurodevelopmental outcome of Malaysian very low birthweight children at 4 years of ageJOURNAL OF PAEDIATRICS AND CHILD HEALTH, Issue 4 2001LC Ong Objective: To determine neonatal, early developmental and social risk factors that predict the neurocognitive and behavioural outcome of very low birthweight (VLBW) preschool children at four years of age. Methodology: From a cohort of 151 eligible VLBW survivors born in Kuala Lumpur Maternity Hospital, 116 (76.8%) were prospectively followed up from birth till four years. A standardised neurological examination was performed at one and four years to determine the presence of impairment and cerebral palsy, respectively. Cognitive development was assessed using the Mental Scale of the Bayley Scales of Infant Development (MDI) at one year and the Weschler Preschool and Primary Scale of Intelligence-Revised (WIPPSI-R) at four years. Motor coordination was assessed using the Movement Assessment Battery for Children (Movement-ABC). Mothers completed the Child Behaviour Checklist (CBCL) and Parenting Stress Index (PSI) questionnaires. Logistic and multiple regression analyses were used to determine factors associated with cerebral palsy, IQ scores, Movement-ABC and CBCL scores. Results: Factors associated with cerebral palsy were lower MDI scores at one year (P = 0.001) and late neonatal cranial ultrasound abnormalities (P = 0.036). Minor (P = 0.016) or major impairment (P = 0.003) at one year of age and a low level of paternal education (P = 0.01) were associated with poor motor function on the Movement-ABC scale. Lower levels of maternal education (P < 0.001), impairment at one year (P = 0.002) and late neonatal cranial ultrasound abnormalities (P = 0.039) predicted Full Scale IQ scores. Higher PSI scores (P = 0.001), younger mothers (P = 0.003) and late neonatal cranial ultrasound abnormalities (P = 0.009) were associated with worsened child behaviour scores on the CBCL scale. Conclusion: Social factors and the caregiving environment were important determinants of cognitive and behavioural outcome. Cranial ultrasound abnormalities in the late neonatal period and the developmental status at one year might be useful in identifying high risk infants in need of long-term surveillance. [source] Multi-walled carbon nanotubes encapsulated with polyurethane and its nanocompositesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 14 2008Xiao Wang Abstract Poly(acryloyl chloride) (PACl) was employed to enhance the surface of multi-walled carbon nanotubes (MWCNTs). MWCNTs were first acid treated to generate hydroxyl groups on the surface, which was reacted with PACl to obtain an encapsulation. The numerous acryloyl chloride groups on the out layer were esterified with a proper amount of ethylene glycol (EG). Subsequently, 4,4,-methylenebis (phenylisocyanate) (MDI) and 1,4-butanediol (BDO) were introduced into the system, and a polyurethane (PU) layer was formed in situ. The formation of PU layers on MWCNTs was confirmed by Fourier transform infrared spectrometer (FTIR) and X-ray photoelectron spectroscope (XPS). The morphology of encapsulated MWCNTs was observed by transmission electron microscope (TEM) and scanning electron microscope (SEM). Thermo gravimetric analysis (TGA) showed the grafted polymer fraction was up to 90%. On introducing the modified MWCNTs into a PU matrix, an increase in tensile strength by 60.6% and improvement in modulus by 6.3% over neat PU was observed. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4857,4865, 2008 [source] Poly(tetramethylene ether) glycol containing acetal linkages: New PTMG-based polyol for chemically recyclable polyurethane thermoplastic elastomerJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 5 2008Tamotsu Hashimoto To develop new chemically recyclable polyurethane elastomers, the poly(tetramethylene ether) glycol (PTMG) containing acetal linkages (PTMG-Acetal-OH) was prepared and subjected to the polyurethane synthesis with 4,4(-diphenylmethane diisocyanate (MDI) and 1,4-butanediol (BD; chain-extender). The obtained polyurethane (PTMG-Acetal-PU) shows very similar mechanical and thermal properties to those of the conventional PTMG-based thermoplastic polyurethane elastomers (PTMG-PU). The acid treatment of PTMG-Acetal-PU at room temperature caused hydrolysis reaction of their acetal units to regenerate PTMG as a degradation product. [source] Synthesis and properties of poly(carbonate-urethane) consisting of alternating carbonate and urethane moietiesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 9 2006Bungo Ochiai Abstract Poly(carbonate-urethane) consisting of alternating carbonate and urethane moieties (poly(HC-MDI)) was prepared by polyaddition of 4,4,-diphenylmethane diisocyanate (MDI) and a monocarbonate diol bis(3-hydroxypropyl)carbonate (HC), prepared by hydrolysis of a six-membered spiroorthocarbonate 1,5,7,11-tetraoxa-spiro[5.5]undecane. The polyaddition proceeds without concomitant side reactions including carbonate exchange reaction and affords the desired poly(carbonate-urethane). The hydrolysis and thermal behaviors of poly(HC-MDI) were compared with those of the analogous polyurethane carrying no carbonate structure (poly(ND-MDI)) prepared from MDI and 1,9-nonanediol (ND). Although the glass transition behaviors are almost identical, poly(HC-MDI) is less crystalline than poly(ND-MDI). Poly(HC-MDI) is more susceptible to hydrolysis than poly(ND-MDI) probably due to the higher polarity and the lower crystallinity. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2802,2808, 2006 [source] Synthesis and characterization of polyurethane,urea nanoparticles containing methylenedi- p -phenyl diisocyanate and isophorone diisocyanateJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 17 2004In Woo Cheong Abstract Water-based polyurethane,urea (WPUU) nanoparticles containing 4,4,-methylenedi- p -phenyl diisocyanate (MDI) and isophorone diisocyanate (IPDI) were synthesized by a stepwise prepolymer mixing process, that is, the consecutive formation of hydroxyl-terminated and isocyanate-terminated polyurethane prepolymers. The reaction behavior, chemical structure, and consequent morphology of the polyurethane prepolymers and WPUU were investigated with Fourier transform infrared (FTIR), gel permeation chromatography, and NMR techniques with MDI concentrations ranging from 0 (pure IPDI) to 50% with respect to the total moles of isocyanate. Wide-angle X-ray diffraction and differential scanning calorimetry patterns showed that the crystallinity of WPUU, which mostly originated from crystallizable poly(tetramethylene adipate) polyol, was significantly affected by the MDI content. Both the crystallinity and melting temperature of WPUU decreased as the MDI content increased. Deconvoluted relative peak areas of the carbonyl region in the FTIR spectrum revealed that the effect of hydrogen bonding among the hard segments became favorable as the MDI content increased, whereas the hydrogen bonding of the soft segments significantly decreased. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4353,4369, 2004 [source] Synthesis and properties of segmented main-chain liquid-crystalline polyurethanes with a high aspect ratio mesogenic diol as a chain extenderJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 10 2002T. Padmavathy Abstract Main-chain liquid-crystalline polyurethanes were synthesized based on a high aspect ratio mesogenic diol (4-{[4-(6-hydroxyhexyloxy)-phenylimino]-methyl}-benzoic acid 4-{[4-(6-hydroxyhexyloxy)-phenylimino]-methyl}-phenyl ester) as a chain extender; polycaprolactone (PCL) diol soft segments of different number-average molecular weights (530, 1250, or 2000); and different diisocyanates, including 1,4-hexamethylene diisocyanate (HMDI), 4,4,-methylene bis(cyclohexyl isocyanate) (H12MDI), and 4,4,-methylene bis(phenyl isocyanate) (MDI). The structure of the polymers was confirmed with Fourier transform infrared spectroscopy, and differential scanning calorimetry and polarizing microscopy measurements were carried out to examine the liquid-crystalline and thermal properties of the polyurethanes, respectively. The mesogenic diol was partially replaced with 20,50 mol % PCL. A 20 mol % mesogen content was sufficient to impart a liquid crystalline property to all the polymers. The partial replacement of the mesogenic diol with PCL of various molecular weights, as well as the various diisocyanates, influenced the phase transitions and the occurrence of mesophase textures. Characteristic liquid-crystalline textures were observed when a sufficient content of the mesogenic diol was present. Depending on the flexible spacer length and the mesogenic content, grained and threadlike textures were obtained for the HMDI and H12MDI series polymers, whereas the polyurethanes prepared from MDI showed only grained textures for all the compositions. The polymers formed brittle films and could not be subjected to tensile tests. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1527,1538, 2002 [source] Citri Reticulatae Pericarpium extract suppresses adipogenesis in 3T3-L1 preadipocytesJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 13 2007Fuu Sheu Abstract This study examined how Citrus herbal medicines,Citri Reticulatae Pericarpium (CRP), Citri Reticulatae Viride Pericarpium (CRVP), Aurantii Immaturus Fructus (AIF) and Aurantii Fructus (AF),affect the differentiation of 3T3-L1 adipocytes. Eight days after induction for differentiation with 3-isobutyl-1-methylxanthine, dexamethasone and insulin (MDI) medium and simultaneously with the tested CRP, intracellular triacylglycerol accumulations of 3T3-L1 cells were significantly (P < 0.05) reduced compared with those for CRVP, AIF and AF and those of the vehicle control. This suppression affect was dose-dependent, and decreases in triacylglycerol production of 12.6, 18.7, 34.05 and 49.6% were observed for CRP at concentrations of 50, 100, 150 and 200 µg mL,1 respectively. Additionally, the expression of key transcription factors for the 3T3-L1 adipogenesis gene, including PPAR-,, C/EBP-, and SREBP-1, was markedly reduced by CRP treatment. These results suggest that dietary CRP suppresses 3T3-L1 differentiation by down-regulation of adipogenic transcription factors. Experimental data may prove useful in further medical examination of the use of CRP for body weight control. Copyright © 2007 Society of Chemical Industry [source] Enhanced Biocompatibility in Biostable Poly(carbonate)urethaneMACROMOLECULAR BIOSCIENCE, Issue 4 2004Shan-hui Hsu Abstract Summary: In this work, we synthesized two MDI-based polyurethanes, including a poly(ether)urethane (PEU) and a poly(carbonate)urethane (PCU), by using different soft segments, poly(tetramethylene oxide) and poly(hexyl, ethyl)carbonate diol (,,,2,000). We demonstrated that, in addition to the enhanced biostability of PCU over PEU, the biological performances of PCU in vitro were also improved in general. These included, better cellular attachment and proliferation, less platelet activation, as well as reduced monocyte activation. The unusual wide-ranging enhancement in biocompatibility for PCU was believed to be related to the larger micro-phase separation in PCU (,25 nm) that caused distinct protein adsorption on the surface. The total number of adherent monocytes (nonactivated and activated) on the bare sample surfaces, albumin pre-adsorbed sample surfaces, and fibrinogen pre-adsorbed sample surfaces. [source] Hydroxylated Linear Polyurethanes Derived from Sugar AlditolsMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 6 2009Romina Marín Abstract A set of linear [m,n]-type polyurethanes was synthesized by reaction of HDI or MDI with conveniently protected sugar alditols L -threitol (LTh), L -arabinitol (LAr) and xylitol (Xy). of the resulting polyurethanes ranged between 10,000 and 60,000 with polydispersities around 2. They were thermally stable, showing no decomposition up to temperatures near 300,°C. They all were amorphous polymers with Tg highly dependent on the constitution of the diisocyanate, but scarcely dependent on the structure of the alditol. Hydrogenation of the LThBn-HDI polyurethane yielded partially debenzylated products with Tg values ranging between 20 and 30,°C. Fully benzylated polyurethanes showed high resistance to hydrolytic degradation, whereas polyurethane with free hydroxyl side groups degraded significantly in saline buffer at pH,=,10 and 37,°C. [source] Thermoplastic Polyurethanes with Poly(butylene terephthalate) as Crystallizable Hard PhaseMACROMOLECULAR MATERIALS & ENGINEERING, Issue 3 2008Debasish De Abstract Polyurethanes were prepared from poly(tetramethylene oxide) end-capped with MDI and PBT extenders. The PBT extenders were random-disperse in length and their length varied from three to seven repeating units. The structure of the polyurethanes was studied by FT-IR and AFM, their thermal and thermomechanical responses were measured by DSC and DMTA, and their elastic behavior was assessed by compression set measurements. The MDI-PBT-MDI hard segments had a ribbon-like crystalline morphology. Increasing the PBT length gave rise to an increase of the storage modulus at room temperature and the melting point. The storage modulus depended strongly on temperature. [source] Anomalous variations in low-degree helioseismic mode frequenciesMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2006R. Howe ABSTRACT We compare changes in the frequencies of solar acoustic modes with degree between 0 and 2, as derived from Global Oscillation Network Group (GONG), Birmingham Solar Oscillations Network (BiSON) and Michelson Doppler Imager (MDI) spectra obtained between 1995 and 2003. We find that, after the solar-activity dependence has been removed from the frequencies, there remain variations that appear to be significant, and are often well correlated between the different data sets. We consider possible explanations for these fluctuations, and conclude that they are likely to be related to the stochastic excitation of the modes. The existence of such fluctuations has possible relevance to the analysis of other low-degree acoustic mode spectra such as those from solar-type stars. [source] | ||||||||||||||||||||||||||||||||||||||||