Search

Single-crystal metastable Bl-NaCl-structure delta-TaN(sub x) layers with x ranging from 0.94 to 1.37 were grown on MgO(001) at T(sub s)=600degreeC by UHV magnetically unbalanced reactive magnetron sputter deposition. All layers exhibited an epitaxial cube-on-cube relationship with the substrate: (001)(sub TaN)//(001)(sub MgO) and [100](sub TaN)//[100](sub MgO)

Summary: Romosozumab, a sclerostin antibody, exerts dual effect to increase bone formation and decrease bone resorption. Among high-risk postmenopausal East Asian women, romosozumab followed by alendronate was associated with lower incidences of fractures vs alendronate alone. Romosozumab demonstrates potential to address an unmet need in osteoporosis management in Asia. Introduction: Romosozumab, a sclerostin antibody, exerts dual effect to increase bone formation and decrease bone resorption. The global ARCH study demonstrated superiority of romosozumab followed by alendronate in reducing fracture risk in high-risk postmenopausal osteoporotic women vs alendronate alone. We report outcomes among ARCH East Asian patients. Methods: In ARCH, 4093 postmenopausal osteoporotic women with fragility fracture were randomized 1:1 to monthly romosozumab 210 mg or weekly alendronate 70 mg for 12 months, both followed by open-label alendronate. Primary endpoints were incidence of new vertebral fracture (VF) at 24 months and clinical fracture at primary analysis (confirmed fractures in ≥ 330 patients and all patients had opportunity to attend month 24 visit). This post hoc analysis was not powered to detect fracture-rate differences. Results: This analysis included 275 patients from Hong Kong, Korea, and Taiwan. Romosozumab followed by alendronate reduced risk of new VFs at 24 months by 60% (P = 0.11) and clinical fractures at primary analysis by 44% (P = 0.15) vs alendronate alone. Romosozumab followed by alendronate significantly increased mean bone mineral density at 24 months from baseline by a further 9.0%, 3.3%, and 3.0% at the lumbar spine, total hip, and femoral neck vs alendronate alone. Adverse event (AE) rates, including positively adjudicated serious cardiovascular AEs (1.6% vs 1.4% at 12 months for romosozumab vs alendronate), were similar across treatment groups. Conclusions: Consistent with the global analysis, romosozumab followed by alendronate was associated with lower incidences of new vertebral, clinical, non-vertebral, and hip fractures vs alendronate alone among East Asian patients. [ABSTRACT FROM AUTHOR]

Epitaxial NaCl-structure δ-TiNx(001) layers, with x ranging across the single-phase compound field from 0.67 to 1.00, are grown on MgO(001) and analyzed by Raman spectroscopy. All samples, including stoichiometric TiN(001), exhibit first-order Raman peaks, which are forbidden by the Oh symmetry of NaCl-structure compounds. Thus, even stoichiometric TiN contains point defects, primarily N and Ti vacancies, consistent with previous electronic transport measurements. However, the presence of a well-resolved second-order longitudinal acoustic line at 615 cm-1 shows that the defect concentration is relatively low. The positions of the first-order acoustic lines are in good agreement with values obtained from calculated phonon density of states. As the N/Ti ratio x in TiNx and, hence, the number n of valence electrons per formula unit (n = 9 for stoichiometric TiN) decreases, the first-order acoustic lines shift to higher frequencies, due to the corresponding decrease in phonon anomalies associated with the acoustic branch. This is in agreement with the observed increase in the intensities of the first-order acoustic phonon peak with decreasing x, characteristic of a higher average N vacancy concentration adjacent to Ti atoms. However, the presence of antisite defects is also required to explain the frequency shift of the optical modes in under-stoichiometric TiNx. [ABSTRACT FROM AUTHOR]

Single-crystal group-V δ-TaNx transition-metal (TM) nitride layers, with x ranging from 0.94 to 1.37, are grown on MgO(001) and analyzed by Raman spectroscopy. In perfect NaCl-structure crystals, the first-order Raman modes are not allowed by the Oh crystal symmetry. Since first-order acoustic and optical bands are observed for all δ-TaNx samples, this indicates the presence of point defects, even for stoichiometric TaN. The large mass difference between Ta and N leads to a correspondingly large separation between the first-order acoustic and optical bands centered at 150 and 550 cm-1, respectively. A Raman peak at 440 cm-1, overlapping the first-order optical band, is identified as the difference between the first-order optical and acoustic modes. Contrary to the case for most TM nitrides, there is no peak visible in the second-order high-frequency range (700–1500 cm-1). In addition, the first-order transverse (120 cm-1) and longitudinal acoustic peaks (175 cm-1) do not exhibit the frequency shift with N/Ta ratio x (i.e., with the valence electron density) that has been reported for group-IV TM nitrides. This is consistent with the resistivity of TaNx remaining essentially constant, as well as with the very weak dependence of the lattice parameter as a function of the N/Ta ratio, and suggests that the wide single-phase region in this system is due to the presence of isoelectronic antisite substitutions rather than, as has been proposed previously, cation and anion vacancies. [ABSTRACT FROM AUTHOR]

CaF2-structure CoSi2 layers were formed on Si(001) by reactive deposition epitaxy (RDE) and compared with CoSi2 layers obtained by conventional solid phase growth (SPG). In both sets of experiments, Co was deposited by ultrahigh-vacuum magnetron sputtering and CoSi2 formed at 600 °C. However, in the case of RDE, CoSi2 formation occurred during Co deposition while for SPG, Co was deposited at 25 °C and silicidation took place during subsequent annealing. X-ray diffraction pole figures and transmission electron microscopy results demonstrate that RDE CoSi2 layers are epitaxial with a cube-on-cube relationship, (001)CoSi2∥(001)Si and [100]CoSi2∥[100]Si. In contrast, SPG films are polycrystalline with an average grain size of ≃1000 Å and a mixed 111/002/022/112 orientation. We attribute the striking difference to rapid Co diffusion into the Si(001) substrate during RDE for which the high Co/Si reactivity gives rise to a flux-limited reaction resulting in the direct formation of the disilicide phase. In contrast, sequential nucleation and transformation among increasingly Si-rich phases—from orthorhombic Co2Si to cubic CoSi to CoSi2—during SPG results in polycrystalline layers with a complex texture. [ABSTRACT FROM AUTHOR]