530 research outputs found
Ethical Considerations Surrounding Survival Benefit-Based Liver Allocation
poster abstractThe disparity between the demand for and supply of donor livers has continued to grow over the last two decades, placing greater weight on the need for efficient and effective allocation. Although the use of extended criteria donors (ECD) has shown greater potential, it remains unregulated. Schaubel et al. have recently proposed a survival benefit model which balances waitlist survival and potential transplantation benefit for a given quality of donor liver. The OPTN/UNOS Liver and Intestinal Organ Transplantation Committee considered this and other models in a recent report, concluding that the current allocation method does not require modification.
In order to further evaluate the survival benefit model, the various ethical concerns shaping organ allocation were discussed and used to identify strengths and shortcomings associated with the proposed model. Compared to the current MELD/PELD system, the survival benefit model incorporates a greater number of ethical principles, uses a sophisticated statistical model to increase efficiency and reduce waste, minimizes bias, and parallels developments in the allocation of other organs. Conversely, the model fails to address quality of life concerns, prioritization for younger patients, its less promising posttransplant prediction accuracy, and potential issues regarding informed consent and economic burdens. To remedy these issues, we suggested incorporating various improvements based on recent literature. Although limitations exist, the survival benefit model now exists as a better means of improving allocation. We support the model proposed by Schaubel et al., with the amendments we suggested, and urge the OPTN/UNOS Liver and Intestinal Organ Transplantation Committee and the transplant community to strongly consider this model as another step toward better liver allocation
Fatigue as Reported at 12 Time Points during the First Year Post-Liver Transplant
abstractBACKGROUND: Although liver transplantation has evolved as an effective procedure, fatigue remains a post-transplant complaint [1]. As yet, there are no published accounts of the experience of fatigue at temporal intervals during the first post-transplant year, and this information would benefit LT candidates in recovery planning. Van Ginneken [2] found that time since transplant was not associated with physical fatigue and reduced activity, but was associated with albumin levels less than 25g/l and with lower GFR.
METHODS: Data used in this study were collected through an ongoing, longitudinal, prospective design. Results presented here are for fatigue and biometric data at 12 data points starting one week post hospital discharge, continued weekly for the first 8 weeks, then monthly at 3, 6, 9, and 12 months.
RESULTS: We sampled 30 subjects: 19 (70.4%) male and 8 (29.6%) female, age 55.4 ± 9.8 years. A mixed models analysis of variance was done to investigate a change in FACIT over time. The initial model included age, MELD, sex, week, albumin, ALT, BILI T, and CREAT. The final model included age, BILI T, and week. Increasing age and BILI T were associated with greater fatigue (p=0.0376 and p=0.0005, respectively). There was significant decrease in fatigue over time (p<0.0001). Pair-wise comparisons were done to determine which weeks significantly differed. Tukey’s adjustment for multiple comparisons was used. Figure 1 indicates which visits significantly differed.
DISCUSSION: Our subjects experienced decreased fatigue over time. The data set was rich with prospectively collected longitudinal information helpful for establishing realistic expectations for post-transplant fatigue. Finding include early weeks of recovery (weeks 2-3) differ from weeks 7+ and that there is no significant change after 3 months, up to one year. No association was seen with Albumin levels although total bilirubin and age were associated with greater fatigue
The alkene monooxygenase from Xanthobacter Py2 is a binuclear non-haem iron protein closely related to toluene 4-monooxygenase
AbstractThe genes encoding the six polypeptide components of the alkene monooxygenase from Xanthobacter Py2 have been sequenced. The predicted amino acid sequence of the first ORF shows homology with the iron binding subunits of binuclear non-haem iron containing monooxygenases including benzene monooxygenase, toluene 4-monooxygenase (>60% sequence similarity) and methane monooxygenase (>40% sequence similarity) and that the necessary sequence motifs associated with iron co-ordination are also present. Secondary structure prediction based on the amino acid sequence showed that the predominantly α-helical structure that surrounds the binuclear iron binding site was conserved allowing the sequence to be modelled on the co-ordinates of the methane monooxygenase α-subunit. Significant differences in the residues forming the hydrophobic cavity which forms the substrate binding site are discussed with reference to the differences in reaction specificity and stereospecificity of binuclear non-haem iron monooxygenases
Oxygen defect in YBa\u3csub\u3e2\u3c/sub\u3eCu\u3csub\u3e3\u3c/sub\u3eO\u3csub\u3ex\u3c/sub\u3e: An x-ray photoemission approach
A combined x-ray photoemission and diamagnetic-susceptibility study of YBa2Cu3Ox with x≃6 and 7 has been performed, with emphasis on the oxygen defect and the effect of heating in vacuum. By comparing spectra taken at these two oxygen contents, the core levels observed in the O 1s and Ba 4d spectral range are identified. Peak-intensity analysis indicates (1) that the oxygen released during the in situ heating is derived from or near the Cu-O-Cu-O chains of YBa2Cu3O7 and (2) that there is a random distribution of oxygen defects in or near these chains leading to two chemically dissimilar barium atoms even in single-orthorhombic-phase samples
Prologue: a focus on learning as universities change
The prologue has two aims. First, it addresses critical challenges for university renewal, and the centrality of the scholarship of teaching and learning. Second, it sketches issues in Hong Kong's higher education. The prologue provides a context for the selected contributions.published_or_final_versio
Break-junction tunneling measurements of the high-\u3ci\u3eT\u3c/i\u3e\u3csub\u3e\u3ci\u3ec\u3c/i\u3e\u3c/sub\u3e superconductor Y\u3csub\u3e1\u3c/sub\u3eBa\u3csub\u3e2\u3c/sub\u3eCu\u3csub\u3e3\u3c/sub\u3eO\u3csub\u3e9- δ \u3c/sub\u3e
Current-voltage tunneling characteristics in a high-critical-temperature superconducting material containing predominately Y1Ba2Cu3O9- δ have been measured using the break-junction technique. Sharp gap structure was observed, with the largest superconductive energy gap measured to be Δ=19.5±1 meV, assuming a superconductor-insulator-superconductor junction. This energy gap corresponds to 2Δ/kBTc=4.8 at T=4 K, for a critical temperature of 93 K (midpoint of the resistive transition)
Superconducting Tl-Ba-Ca-Cu-O films by sputtering
Superconducting Tl-Ba-Ca-Cu-O thin films 0.2–1.0 µm thick have been prepared on MgO(100) and SrTiO3 (100) substrates by dc diode sputtering using a single oxide target. Films containing primarily the Tl2Ba2Ca1Cu2O8 phase were obtained with a Tc (R =0) at 102 K and a transport Jc of 104 A/cm2 at 90 K. For the nearly pure phase Tl2Ba2Ca2Cu3O10 films, the Tc\u27s (R =0) are higher at 116 K and the transport Jc\u27s at 100 K are of 105 A/cm2. Both types of films show a strong preferred orientation with the c axis perpendicular to the film plane. The rocking curve of the Tl2Ba2Ca2Cu3O10 films is 0.32° wide and the typical grain size is over 10 µm
Magnetic properties of epitaxial single crystal ultrathin Fe\u3csub\u3e3\u3c/sub\u3eSi films on GaAs (001)
Magnetic properties of Fe3Si films with thickness from 2 to 210 monolayers (ML) epitaxially grown on GaAs (001) were studied using a superconducting quantum interference device and alternating gradient force magnetometers. Growth of these single-crystal intermetallic compound films were carried out in a multichamber molecular beam epitaxy (MBE) system. The samples were covered in situ with Au 50 Ã… thick to prevent oxidation when the samples were removed from the MBE chamber. All the films are ferromagnetic even for samples as thin as 2 ML. The easy magnetization direction of the films is parallel to the film surface. The magnetic coercivity forces (Hc) of the samples increase as the film thickness decreases to 10 ML, and then decrease when the film thickness decreases further to 2 ML
Superconducting Tl-Ba-Ca-Cu-O films by sputtering
Superconducting Tl-Ba-Ca-Cu-O thin films 0.2–1.0 µm thick have been prepared on MgO(100) and SrTiO3 (100) substrates by dc diode sputtering using a single oxide target. Films containing primarily the Tl2Ba2Ca1Cu2O8 phase were obtained with a Tc (R =0) at 102 K and a transport Jc of 104 A/cm2 at 90 K. For the nearly pure phase Tl2Ba2Ca2Cu3O10 films, the Tc\u27s (R =0) are higher at 116 K and the transport Jc\u27s at 100 K are of 105 A/cm2. Both types of films show a strong preferred orientation with the c axis perpendicular to the film plane. The rocking curve of the Tl2Ba2Ca2Cu3O10 films is 0.32° wide and the typical grain size is over 10 µm
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