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Metal-metal bonding interactions can engender outstanding magnetic properties in bulk materials and molecules, and examples abound for the transition metals. Extending this paradigm to the lanthanides, herein we report mixed-valence dilanthanide complexes (CpiPr5)2Ln2I3 (Ln is Gd, Tb, or Dy; CpiPr5, pentaisopropylcyclopentadienyl), which feature a singly occupied lanthanide-lanthanide s-bonding orbital of5dz2 parentage, as determined by structural, spectroscopic, and computational analyses. Valence delocalization, wherein the d electron is equally shared by the two lanthanide centers, imparts strong parallel alignment of the s-bonding and f electrons on both lanthanides according to HundÕs rules. The combination of a well-isolated high-spin ground state and large magnetic anisotropy in (CpiPr5)2Dy2I3 gives rise to an enormous coercive magnetic field with a lower bound of 14 tesla at temperatures as high as 60 kelvin. [ABSTRACT FROM AUTHOR]

The partially fluorinated oxo-alkoxide tungsten(VI) complexes WO(OR)4 [4; R = C(CH3)2CF3, 5; R = C(CH3)(CF3)2] have been synthesized as precursors for chemical vapour deposition (CVD) of WOx nanocrystalline material. Complexes 4 and 5 were prepared by salt metathesis between sodium salts of the fluoroalkoxides and WOCl4. Crystallographic structure analysis allows comparison of the bonding in 4 and 5 as the fluorine content of the fluoroalkoxide ligands is varied. Screening of 5 as a CVD precursor by mass spectrometry and thermogravimetric analysis was followed by deposition of WOx nanorods. [ABSTRACT FROM AUTHOR]

Tungsten nitrido complexes of the form WN(NR2)3 [R = combinations of Me, Et, iPr, nPr] have been synthesized as precursors for the chemical vapor deposition of WNxCy, a material of interest for diffusion barriers in Cu-metallized integrated circuits. These precursors bear a fully nitrogen coordinated ligand environment and a nitrido moiety (W≡N) designed to minimize the temperature required for film deposition. Mass spectrometry and solid state thermolysis of the precursors generated common fragments by loss of free dialkylamines from monomeric and dimeric tungsten species. DFT calculations on WN(NMe2)3 indicated the lowest gas phase energy pathway for loss of HNMe2 to be β-H transfer following formation of a nitrido bridged dimer. Amorphous films of WNxCy were grown from WN(NMe2)3 as a single source precursor at temperatures ranging from 125 to 650 °C using aerosol-assisted chemical vapor deposition (AACVD) with pyridine as the solvent. Films with stoichiometry approaching W2NC were grown between 150 and 450 °C, and films grown at 150 °C were highly smooth, with a RMS roughness of 0.5 nm. In diffusion barrier tests, 30 nm of film withstood Cu penetration when annealed at 500 °C for 30 min. [ABSTRACT FROM AUTHOR]

The WN x precursor WN(NMe2)3 was prepared from WN(O tBu)3 and Zr(NMe2)4 by using an amide/alkoxide exchange reaction. Structural analysis of WN(NMe2)3 revealed an overall pseudo-tetrahedral geometry with a distortion towards trigonal pyramidal. Aerosol-assisted chemical vapor deposition (AACVD) from WN(NMe2)3 resulted in deposition of WN x nanospheres onto Si(100) and Si(111) substrates at low temperatures (75-125 °C). The nanospheres were imaged by SEM and characterized by using energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). These preliminary results demonstrate the viability of WN(NMe2)3 as a single-source precursor for the deposition of WN x at low temperature. [ABSTRACT FROM AUTHOR]

Despite the favorable outcome of most pediatric patients with Hodgkin lymphoma (HL), there is rising concern about risks of carcinogenesis from both diagnostic and therapeutic radiation exposure for patients treated on study protocols. Although previous studies have investigated radiation exposure during treatment, radiation from post-treatment surveillance imaging may also increase the likelihood of secondary malignancies. All diagnostic imaging examinations involving ionizing radiation exposure performed for surveillance following completion of therapy were recorded for 99 consecutive pediatric patients diagnosed with HL from 2000 to 2010. Cumulative radiation dosage from these examinations and the frequency of relapse detection by these examinations were recorded. In the first 2 years following completion of therapy, patients in remission received a median of 11 examinations (range 0-26). Only 13 of 99 patients relapsed, 11 within 5 months of treatment completion. No relapse was detected by 1- or 2-view chest radiographs ( n = 38 and 296, respectively), abdomen/pelvis computed tomography (CT) scans ( n = 211), or positron emission tomography (PET) scans alone ( n = 11). However, 10/391 (2.6%) of chest CT scans, 4/364 (1.1%) of neck CT scans, and 3/47 (6.4%) of PET/CT scans detected relapsed disease. Thus, only 17 scans (1.3%) detected relapse in a total of 1358 scans. Mean radiation dosages were 31.97 mSv for Stage 1, 37.76 mSv for Stage 2, 48.08 mSv for Stage 3, and 51.35 mSv for Stage 4 HL. Approximately 1% of surveillance imaging examinations identified relapsed disease. Given the very low rate of relapse detection by surveillance imaging stipulated by current protocols for pediatric HL patients, the financial burden of the tests themselves, the high cure rate, and risks of second malignancy from ionizing radiation exposure, modification of the surveillance strategy is recommended. [ABSTRACT FROM AUTHOR]

PURPOSE: This study sought to describe the physical activity-endometrial cancer association and potential mediation of this relationship by obesity in midlife. METHODS: Participants were 67,705 women (aged 50-71 years) enrolled in the NIH-AARP cohort who reported their historical leisure-time physical activity patterns starting at age 15-18 years. We identified five long-term physical activity patterns between adolescence and cohort entry (i.e., inactive, maintained-low, maintained-high, increasers, decreasers). We used Cox regression (Hazard ratio - HR [95% CI]) to assess the relationship between these patterns and midlife obesity and endometrial cancer, adjusting for covariates. Mediation analysis was used to decompose the physical activity patterns-endometrial cancer association to estimate the proportion of the physical activity-endometrial cancer association mediated by midlife obesity. RESULTS: During an average 12.3 years of follow-up 1,468 endometrial cancers occurred. Long-term physical activity patterns were inactive, maintained-low, maintained-high, increasers, and decreasers. Compared to long-term inactive women, women who maintained-high or increased activity levels had a 19-26% lower risk for endometrial cancer (maintained-high: HR = 0.81 [0.67, 0.98]; increasers: HR = 0.74 [0.61, 0.91]). They also had a 45-77% lower risk for obesity in midlife (e.g., maintained-high, BMI 30-39.9: HR = 0.50 [0.46, 0.55]; maintained-high, BMI 40+: HR = 0.32 [0.26, 0.39]). Obesity was a significant mediator and appeared to account for 55-63% of the physical activity-endometrial cancer associations observed. CONCLUSIONS: Both initiating and maintaining physical activity throughout adulthood can play a role in preventing obesity and in turn, lowering the risk for endometrial cancer. [ABSTRACT FROM AUTHOR]

Malignant non-Hodgkin's lymphomas (NHL) of childhood and adolescence are a heterogeneous group of diseases originating from the lymphoid cells. Unlike adults with non-Hodgkin's lymphoma, children typically have extranodal disseminated disease of high grade (Burkitt's lymphoma, large cell lymphoma, or lymphoblastic lymphoma). This study was conducted to determine the feasibility of treating children in the Czech Republic with B-cell non-Hodgkin's lymphomas according to very intensive protocols based on the German Berlin Frankfurt Munster (BFM) NHL 90 study. Treatments are divided in the BFM studies according to "B" and "non-B" immunophenotypes. The authors report only those treated according to the BFM B-cell protocol. From 1991 through 1997 eighty-two patients less than 18 years with NHL were admitted to the department. Seventy-three of them were classified as B-cell lymphoma and 54 were thus eligible for the BFM B-cell treatment. The entire group consisted of 38 males and 16 females (ratio 2.38). Median age was 11.6 years. Twelve had stage I disease, 3 stage II, 30 stage III, and 9 stage IV lymphoma. There were 21 patients with Burkitt's lymphoma, 29 with large cell lymphoma, of which 5 were patients with MALT lymphoma. In 3 cases B-cell NHL was not further classified and one child had a mediastinal B lymphoma. Patients were further stratified according to clinical stage and lactate dehydrogenase (LDH) level. Therapy consisted of a prephase and short (2, 4, or 6 courses), intensive 5-day therapy with 6 drugs. The probability of event-free survival (pEFS) for the entire group was 74% and overall survival at 5 years was 80%. There was a significantly better outcome for children classified as stage I. No difference was observed between the EFS of stage III and IV patients. Four patients died from treatment-related complications in complete remission. Treatment results were not identical between NHL subtypes, with large cell lymphoma patients doing significantly better (pEFS 90%, p=.008). The use of protocols based on BFM 90 study was feasible at this center. The treatment results are approximately 10% lower than those reported by BFM investigators, but comparable to results from other centers. [ABSTRACT FROM AUTHOR]

We report the occurrence of multiple leiomyomata and leiomyosarcomata in three children with the acquired immunodeficiency syndrome. The children were infected with human immunodeficiency virus as infants (one perinatally and two through transfusions) and each was profoundly immunosuppressed (absolute CD4 cell count, less than 75/mm3). They experienced multiple infections prior to the diagnosis of neoplasms at ages 4, 5, and 8 years, respectively. The tumors in each case were mainly involving the lungs and gastrointestinal tract. The smooth-muscle origin of the tumors was proved by light and electron microscopy and immunohistochemical staining for muscle-specific actin and desmin. Leiomyomata and leiomyosarcomata are rare tumors in childhood, suggesting a nonrandom association of tumors of smooth-muscle origin and the acquired immunodeficiency syndrome. We postulate that human immunodeficiency virus infection may play a direct or indirect role in tumor formation. [ABSTRACT FROM AUTHOR]

Tungsten nitrido complexes of the type WN(NR2)3 [NR2 = combinations of NMe2, NEt2, NiPr2, NnPr2, NiBu2, piperidine, and azepane] were synthesized as precursors for aerosol-assisted chemical vapor deposition of WNxCy thin films. The effects of the amido substituents on precursor volatility and decomposition were evaluated experimentally and computationally. Films deposited using WN(NMe2)(NiPr2)2 as a single-source precursor were assessed as diffusion barrier materials for Cu metallized integrated circuits in terms of growth rate, surface roughness, composition, and density. In diffusion barrier tests, Cu (~100 nm)/WNxCy (~5 nm)/Si samples prepared from WN(NMe2)(NiPr2)2 were annealed for 30 min at 500 °C and successfully blocked Cu penetration according to four-point probe, X-ray diffraction, scanning electron microscopy etch-pit test, and high-resolution transmission electron microscopy measurements. [ABSTRACT FROM AUTHOR]