Management of hyperleukocytosis in pediatric acute myeloid leukemia using immediate chemotherapy without leukapheresis: results from the NOPHO-DBH AML 2012 Protocol

Hyperleukocytosis (HL) in pediatric acute myeloid leukemia (AML) is associated with severe complications and inferior outcome. We report results on HL patients included in the NOPHO-DBH AML 2012 study. We recommended immediate start of full dose chemotherapy (etoposide [ETO] monotherapy for 5 days as part of the first course), avoiding leukapheresis (LA) and prephase chemotherapy (PCT). Of 714 included patients, 122 (17.1%) had HL, and 111 were treated according to the recommendations with ETO upfront without preceding LA or PCT. The first dose was applied the same day as the AML diagnosis or the day after in 94%. ETO was administered via peripheral veins in 37% of patients without major complications. After initiation of ETO the remaining WBC on days 2-5 was 69%, 36%, 17% and 8% of the pre-treatment level. On day 3, 81% had a WB

Density funtional calculations on hydrogen in palladium-silver alloys

Periodic bulk calculations based on density functional theory within the generalized gradient approximation (GGA) have been used to calculate properties of the palladium-silver metals and alloys P

Preserving the superior rectal artery in laparoscopic sigmoid resection for complete rectal prolapse.

Sigmoid resection is indicated in the treatment of complete rectal prolapse (CRP) in patients with prolonged colorectal transit time (CTT). Its use, however, has been limited because of fear of anastomotic leakage. This study challenges the current practice of dividing the mesorectum by prospectively evaluating the impact of sparing the superior rectal artery (SRA) on leak rates after laparoscopic sigmoid resection (LSR) for CRP. During a 30-month period, data on 33 selected patients with CRP were prospectively collected. Three patients were withdrawn from the analysis, as they had neither resection nor anastomosis. Twenty-nine women and 1 man (median age 55 range 21-83 years) underwent LSR with preservation of SRA for a median CRP of 8 (3-15) cm. There were 20 ASA I and 10 ASA II patients. Ten patients had undergone previous surgery. Four patients complained of dyschezia, whereas incontinence was present in 26 patients. Anal ultrasound showed isolated internal sphincter defects in 2 patients. Four young adults (21-32 years) had normal CTT, whereas 26 older patients had a median CTT of 5(4-6) days. Defecography demonstrated 10 enteroceles, two sigmoidoceles, and one rectal hernia through the levator ani muscle. Mortality was nil. Median operating room time was 180 (120-330) min, suprapubic incision length 5(3-7) cm, estimated blood loss 150 (50-500) mL, specimen length 20 (12-45) cm, solid food resumption 3(1-6) days, and length of stay 4.5(2-7) days. Thirty-day complications were not related to anastomosing and occurred in 20% of the patients. Median follow-up was 34.1 (18-48) months. One patient had a recurrence. Although the evidence provided by the present study suggests that sparing SRA has a favorable impact on anastomotic leak rates, these nonrandomized results need further evaluation. The division of the mesorectum at the rectosigmoid junction seems not necessary, and its sparing should therefore be considered as it may contain anastomotic leak rates

Determining the Optimal Phase-Change Material via High-Throughput Calculations

The discovery and optimization of phase-change and shape memory alloys remain a tedious and expensive process. Here a simple computational method is proposed to determine the ideal phase- change material for a given alloy composed of three elements. Using first-principles calculations, within a high-throughput framework, the ideal composition of a phase-change material between any two assumed phases can be determined. This ideal composition minimizes the interface strain during the structural transformation. Then one can target this ideal composition experimentally to produce alloys with low mechanical failure rates for a potentially wide variety of applications. Here we will provide evidence of the effectiveness of our calculations for a well-known phase- change material in which we predict the ideal composition and compare it to experimental results

Highly destabilized Mg-Ti-Ni-H system investigated by density functional theory and hydrogenography

Using hydrogenography, we recently mapped the thermodynamic properties of a large range of compositions in the quaternary Mg-Ti-Ni-H system. The enthalpy of hydride formation of Mg-Ni alloys is significantly altered upon Ti doping. For a small range of compositions, we find a hydrogenation enthalpy ΔH=-40 kJ (mol H2) -1, which is the desired enthalpy for hydrogen storage at moderate temperature and pressure. This enthalpy value is surprising since it is significantly less negative than the ΔH of the Mg-Ni and Mg-Ti hydrides. The nanostructure of the Mg-Ti-Ni-H films hinders a direct determination of the hydride phases involved by x-ray diffraction. Using density functional theory calculations for various hydrogenation reaction paths, we establish that the destabilization of the Mg-Ni-H system by Ti doping is due to the formation of Mg2 Ni and Ti-Ni intermetallics in the as-deposited state, which transform into a metastable Ti-doped Mg2 Ni H4 phase upon hydrogenation. The Ti-doped Mg2 Ni H4 phase can be considered as a heavily doped semiconductor. © 2008 The American Physical Society

Effect of transition metal dopants on initial mass transport in the dehydrogenation of NaAlH4: Density functional theory study

Sodium alanate (NaAlH4) is a prototype system for storage of hydrogen in chemical form. However, a key experimental finding, that early transition metals (TMs) like Ti, Zr, and Sc are good catalysts for hydrogen release (and reuptake) whereas traditional hydrogenation catalysts like Pd and Pt are poor catalysts for NaAlH4, has so far received little attention. We performed density functional theory (DFT) calculations at the PW91 generalized gradient approximation level on Ti, Zr, Sc, Pd, and Pt interacting with the (001) surface of nanocrystalline NaAlH4, employing a cluster model of the complex metal hydride to study the initial mass transport in the dehydrogenation process. A key difference between Ti, Zr, and Sc on one hand and Pd and Pt on the other is that exchange of the early TM atoms with a surface Na ion, whereby Na is pushed on to the surface, is energetically preferred over surface absorption in an interstitial site, as found for Pd and Pt. These theoretical findings are consistent with a crucial feature of the TM catalyst being that it can be transported with the reaction boundary as it moves into the bulk, enabling the starting material to react away while the catalyst eats its way into the bulk and affecting a phase separation between a Na-rich and an Al-rich phase. Additional periodic DFT/PW91 calculations in which NaAlH 4 is modeled as a slab to model dehydrogenation of larger NaAlH 4 particles and which only consider adsorption and absorption of Ti suggest that Ti prefers to absorb interstitially but with only a small energy preference over a geometry in which Ti has exchanged with Na. Additional nudged elastic band calculations based on periodic DFT show only a small barrier (0.02 eV) for exchange of Ti with a surface Na atom. The mechanism inferred from the cluster calculations is therefore consistent with the slab calculations and may well be important. © 2012 American Chemical Society.The work presented here has been supported by a grant from the Dutch research council NWO under the ACTS Hydrogen programme and by a grant of computer time by the Dutch National Computing facilities Foundation (NCF).Peer Reviewe