LiNixMn2−xO4 has been synthesized using sol‐gel and solid‐state methods for 0 < x < 0.5. The electrochemical behavior of the samples was studied in normalLi/LiNixMn2−xO4 coin‐type cells. When x = 0, the capacity of normalLi/LiMn2O4 cells appears at 4.1 V. As x increases, the capacity of the 4.1 V plateau decreases as 1−2x Li per formula unit, and a new plateau at 4.7 V appears. The capacity of the 4.7 V plateau increases as 2x Li per formula unit, so that the total capacity of the samples (both the 4.1 and 4.7 V plateaus) is constant. This is taken as evidence that the oxidation state of Ni in these samples is +2, and therefore they can be written as Li+1Nix+2Mn1−2x+3Mn1+x+4O4−2 . The 4.1 V plateau is related to the oxidation of Mn3+ to Mn4+ and the 4.7 V plateau to the oxidation of Ni2+ to Ni4+ . The effect of synthesis temperature, atmosphere, and cooling rate on the structure and electrochemical properties of LiNi0.5Mn1.5O4 is also studied on samples made by the sol‐gel method. LiNi0.5Mn1.5O4 samples made by heating gels at temperatures below 600°C in air are generally oxygen deficient, leading to Mn oxidation states significantly less than 4. LiNi0.5Mn1.5O4 samples heated above 650°C suffer due to disproportionation into LiNixMn2−xO4 with x < 0.5 and LizNi1−zO with z ≈ 0.2, which occurs above about 650°C. Pure LiNi0.5Mn1.5O4 materials can be made by extended heatings near 600°C or by slowly cooling materials heated at higher temperatures. LiNi0.5Mn1.5O4 made at 600°C has demonstrated good reversible capacity at 4.7 V in excess of 100 mAh/g for tens of cycles.

SUMMARY Background Umbilical cord blood (UCB) is increasingly considered as an alternative to peripheral blood progenitor cells (PBPC) or bone marrow (BM), especially when a HLA-matched adult unrelated donor is not available. Methods In order to establish the appropriateness of current graft selection practices, we retrospectively compared leukemia-free survival and other outcomes for each graft source in patients aged >16 years transplanted for acute leukemia using Cox regression. Data were available on 1525 patients transplanted between 2002 and 2006 using UCB (n=165), PBPC (n=888) and BM (n=472). UCB units were matched at HLA-A and B at antigen level and DRB1 at allele level (n=10) or mismatched at one (n=40) or two antigens (n=115). PBPC and BM grafts from unrelated adult donors were matched for allele-level HLA-A, B, C and DRB1 (n=632; n=332) or mismatched at one locus (n=256; n=140). Findings Leukemia-free survival after UCB transplantation was comparable to that observed after 8/8 and 7/8 allele-matched PBPC or BM transplantation. Transplant-related mortality, however, was higher after UCB transplantation compared to 8/8 allele-matched PBPC (HR 1.62, p<0.01) or BM (HR 1.69, p<0.01). Grades 2–4 acute and chronic graft-versus-host disease were lower in UCB recipients compared to allele-matched PBPC (HR 0.57, p<0.01 and HR 0.38, p<0.01, respectively), while chronic and not acute graft-versus-host disease was lower after UCB compared to allele-matched BM transplantation (HR 0.63, p=0.01). Interpretation Together, these data support the use of UCB for adults with acute leukemia when an HLA-matched unrelated adult donor is lacking and when transplant is urgently needed.

Our results suggest that the COSLOF index could be used as a noninvasive quantitative marker for the preclinical stage of AD.

Although reduced intensity (RIC) and nonmyeloablative (NMA) conditioning regimens have been used for over a decade, their relative efficacy versus myeloablative (MA) approaches to allogeneic hematopoietic cell transplantation (HCT) in patients with acute myelogenous leukemia (AML) and myelodysplasia (MDS) is unknown. We compared disease status, donor, graft and recipient characteristics with outcomes of 3731 MA with 1448 RIC/NMA procedures performed at 217 centers between 1997 and 2004. Five year univariate probabilities and multivariate relative risk (RR) outcomes of relapse, transplant related mortality (TRM), disease free survival (DFS) and overall survival (OS) are reported. Adjusted OS at 5 years was 34%, 33%, and 26% for MA, RIC and NMA transplants, respectively. NMA conditioning resulted in inferior DFS and OS but there was no difference in DFS and OS between RIC and MA regimens. Late TRM negates early decreases in toxicity with RIC and NMA regimens. Our data suggest higher regimen intensity may contribute to optimal survival in patients with AML/MDS, suggesting roles for both regimen intensity and graft vs. leukemia in these diseases. Prospective studies comparing regimens are needed to confirm this finding and determine the optimal approach to patients who are eligible for either MA or RIC/NMA conditioning.

No abstract