New soluble polyimides were synthesized from different 4,4′-diaminodiphenylmethane monomers with different alkyl substituents 4′4′-diamino-3,3′-dimethyl-diphenyl-methane, DDMDPM; 4,4′-methylene ...-bis(2-ethyl-6-methylaniline), MBEMA; and 4,4′-methylene-bis(2,6-diethylaniline), MBDEA in one-step with the poly(amic acid)s prepared from the polyaddition of 4,4′-oxydiphthalic anhydride (ODPA). The structures of the synthesized polyimides were confirmed by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy measurements. The sizes and numbers of alkyl substituents affected the thermal properties, dielectric constants, and solubilities of the polyimides. The obtained polyimides were soluble in various solvents, such as
N
-methyl-2-pyrrolidone (NMP),
N
,
N
-dimethylacetamide (DMAc),
N
,
N
-dimethylformamide (DMF), tetrahydrofuran (THF), dichloromethane (DCM), and chloroform (CClH
3
). These polyimides exhibited excellent thermal stability with a decomposition temperature (T
d
) greater than 500 °C and relatively low coefficients of thermal expansion and dielectric constants. The resulting properties make these new polyimides attractive for practical applications.
Graphical Abstract
Typical mechanism for the synthesis of polyimides from 4,4′-diamino-diphenyl-methane monomers and 4,4′-Oxydiphthalic anhydride
Summary Introduction Mortality of trauma patients is strongly associated with Injury Severity Score (ISS). However, the interaction between ISS and age has not been studied extensively. We evaluated ...ISS in different age groups in relation to mortality rate. Materials and methods This was a retrospective review of 955 trauma patients who visited Mackay Memorial Hospital during January–December 2009. Age, sex, emergency department (ED) stay time, hospital stay time, out-of-hospital cardiac arrest, in-hospital cardiac arrest, ED survival rate, emergency operation, and mortality were analyzed. Patients were separated into two groups by age below or above 65 years, and hospital courses and mortality rate were compared. Results Nine hundred and fifty-five trauma patients visited our ED in 2009: 212 in the aged group (99 male patients; 46.7%) and 743 in the young group (472 male patients; 63.5%). The mean age of the elderly group was 77 ± 8 years (mean ± standard deviation), and 38 ± 16 years in the young group. Mean ISS was 12 ± 12 in the elderly group and 10 ± 13 in the young group. The mean ED stay time was 2.9 ± 3.8 hours for the elderly group and 3.0 ± 4.6 hours for the young group. One hundred and sixty-three patients were admitted and the mean hospital stay time was 12.7 ± 13.6 days in the elderly group, whereas 559 patients were admitted and the mean hospital stay time was 9.9 ± 13.7 days in the young group ( p = 0.018). The mortality rate among hospitalized patients was 3.1% in the elderly group and 2.9% in the young group. On receiver operating characteristic curve analysis, the optimal cut-off ISS for mortality rate among young patients (area under the curve: 0.899) and elderly patients (area under the curve: 0.782) was 17 (sensitivity: 81.3%; specificity: 88.7%) and 14 (sensitivity: 80%; specificity: 82.3%), respectively. Conclusion The elderly group seemed to have no significant difference from the younger group for mortality rate, ED stay time and hospital stay time. In the elderly group, lower ISS predicted a higher mortality than in the younger group.
Antinuclear antibodies (ANAs) are essential diagnostic markers in systemic autoimmune rheumatic diseases. Among the 30 ANA patterns, homogeneous (AC-1) and dense fine speckled (AC-2) should be ...focused on owing to their somewhat indistinct presentation in immunofluorescence imaging and distinct correlation with clinical conditions. This study aimed to develop a flowchart to guide discrimination between AC-1 and AC-2 patterns and to re-evaluate ANA samples according to this flowchart to verify its detection ability. We re-evaluated immunofluorescence imaging of 62 ANA blood samples simultaneously subjected to solid-phase assays for autoantibodies against dsDNA, nucleosomes, histones, and DFS70. The results showed statistically significant odd ratios (ORs) of detection of anti-DFS70 using AC-2 after re-evaluation of total samples (OR 101.9, 95% CI 11.7–886.4, p-value < 0.001) and subgroup analysis of patients’ samples (OR 53.8, 95% CI 5.9–493.6, p-value < 0.001). The OR of anti-nucleosome/histone/dsDNA detection using AC-1 in re-evaluated data increased to 5.43 (95% CI 1.00–29.61, p-value = 0.05). In the analysis of specific autoantibodies, more than half of the samples with an AC-2 pattern (54.2%) had specific autoantibodies other than anti-DFS70. We conclude that the flowchart for discriminating between AC-1 and AC-2 ANA patterns in this study is a viable practical guide for other laboratories when encountering equivocal ANA results.
Introduction The success rate of miniplates is superior to that of other temporary anchorage devices; nevertheless, the biomechanical behavior of miniplates during orthodontic use is not totally ...understood. The aim of this study was to investigate bone stress by finite element analysis when miniplates are used for orthodontic anchorage. Methods A 3-dimensional model consisting of a bone block integrated with a miniplate and fixation screw system was constructed to simulate various types of miniplates, screw numbers, screw lengths, cortex thicknesses, and force magnitudes and directions. Results The peak von Mises cortex stress values were highest with the I-type plates followed by the L-type, Y-type, and T-type plates. Bone stress decreased as the screw numbers increased but was not related to screw length. Bone stress increased as the cortex thickness decreased. Bone stress was linearly proportional to the force magnitude, and the highest values were produced when the force was in the forward direction. Conclusions When a T- or Y-type plate is used, or when the force direction is in the tensile mode, bone stress decreases. Bone stress also decreases as the screw numbers increase and as the cortex thickness increases. Furthermore, it decreases as the force magnitude becomes less.
Scientific Reports 6: Article number: 20786; published online: 10 February 2016; updated: 15 September 2017. In this Article, Affiliation 3 is incorrectly listed as ‘Department of Otolaryngology, ...Taipei Medical University Hospital, Taipei, Taiwan’. The correct affiliation is listed below: Departmentof Otolaryngology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
Abstract Background Renal failure requiring renal replacement therapy (RRT) is associated with a high mortality rate in intensive care unit (ICU) patients. Little information is available on the ...outcomes of patients having prolonged mechanical ventilation (PMV) in addition to RRT. The purpose of this study was to investigate the impact of RRT in PMV patients. Methods This was an observational, retrospective study in the 24-bed respiratory care center (RCC) of Chang Gung Memorial Hospital, Taiwan, between May 2001 and April 2007. The end points were weaning rate and survival rate at the RCC. Results Of the 1301 RCC patients, 157 patients (13.7%) underwent RRT. The RRT patients had lower successful weaning rate (39.5% vs 58.4%, P < .001) and RCC survival rate (45.9% vs 71.9%, P < .001) compared with without-RRT patients. The successful weaning rates of end-stage renal disease (ESRD) patients, patients with RRT initiated at the ICU and continued at RCC, and patients whose RRT was initiated at the RCC were 49.2%, 39.1%, and 22.2%, respectively. The RCC survival rates were 50.8%, 47.8%, and 29.6%, respectively. The odds ratios of successful weaning rate and survival rate were 0.295 (95% confidence interval, 0.105-0.833; P = .021) and 0.407 (95% confidence interval, 0.155-1.021; P = .069) for patients whose RRT was initiated at the RCC vs ESRD patients. Conclusion The present study demonstrates that the need for RRT had a negative impact on weaning and mortality in PMV patients compared with patients without RRT. Patients who had RRT initiated at the RCC had a significantly lower weaning rate compared with ESRD patients.
Room-temperature ferromagnetism (RTFM) was revealed in Fe-doped ZnO vertically aligned nanorod arrays grown by hydrothermal synthesis method. The evolution of RTFM properties and ZnO nanorod quality ...were studied by different growth temperature. At the growth temperature of 80 °C, the vertically aligned ZnO nanorods were well-formed, and Fe readily substituted for Zn in the ZnO nanorod arrays. The weak room temperature ferromagnetism of the Fe-doped ZnO nanorod arrays was determined by magnetization measurements. The morphology and quality of the Fe-doped ZnO nanorods were examined by many structure and composition analysis tools. The Fe atoms were found to be readily incorporated into the ZnO lattice without any precipitation or segregation of the secondary phase in the vertically aligned ZnO nanorod arrays.
Objectives. To estimate the incidence, characteristics and predictors of infections in patients with PM and DM. Methods. The medical records of 192 PM/DM patients followed up in a tertiary teaching ...medical centre from 1999 to 2008 were retrospectively reviewed. Results. Seventy-six episodes of major infection, defined as infections requiring >1 week of treatment with anti-microbial agents, occurred in 53 (27.6%) patients, and 15 (7.8%) patients had two or more episodes. The incidence rate of major infections was 11.1 episodes per 100 patient-years in PM/DM patients. Aspiration pneumonia n (%) = 16 (21.1) was the leading cause of major infections, followed by opportunistic infection n (%) = 14 (18.4). A variety of pathogens were isolated, mainly including Staphylococcus aureus, Klebsiella, Escherichia coli, Salmonella and Mycobacterium. Overall patient survival rates were 85.0% at 1 year, 78.0% at 5 years and 78.0% at 10 years. However, after one episode of major infection, survival rates decreased to 84.7% at 30 days and 68.3% at 1 year. Multivariate analysis indicated that independent predictors of major infection were age >45 years at PM/DM onset odds ratio (OR) 5.26; 95% CI 2.01, 13.77; P = 0.001, presence of arthritis/arthalgia (OR 2.59; 95% CI 1.12, 6.02; P = 0.027), co-present interstitial lung disease (OR 7.24; 95% CI 2.67, 19.65; P < 0.001), current use of AZA (OR 6.07; 95% CI 2.39, 15.42; P < 0.001) or IVIG (OR 6.33; 95% CI 1.50, 26.77; P = 0.012). Conclusions. This study underlines the high frequency of major infections in PM/DM, which is significantly detrimental to patient survival rates. Close follow-up of PM/DM patients with risk factors for developing major infections is mandatory.
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