57 research outputs found
Reversible hydration and aqueous exfoliation of the acetate-intercalated layered double hydroxide of Ni and Al: Observation of an ordered interstratified phase
Acetate-intercalated layered double hydroxides (LDHs) of Ni and Al undergo reversible hydration in the solid state in response to the ambient humidity. The LDH with a high layer charge (0.33/formula unit) undergoes facile hydration in a single step, whereas the LDH with a lower layer charge (0.24/formula unit) exhibits an ordered interstratified intermediate, comprising the hydrated and dehydrated layers stacked alternatively. This phase, also known as the staged S-2 phase, coexists with the end members suggesting the existence of a solution-type equilibrium between the S-2 phase and the end members of the hydration cycle. These LDHs also undergo facile aqueous exfoliation into 2-5 nm-thick tactoids with a radial dimension of 0.2-0.5 μm. © 2012 Elsevier Inc. All rights reserved
Synthesis and reversible hydration behavior of the thiosulfate intercalated layered double hydroxide of Zn and Al
The thiosulfate-intercalated layered double hydroxide of Zn and Al undergoes reversible hydration with a variation in the relative humidity of the ambient. The hydrated and dehydrated phases, which represent the end members of the hydration cycle, both adopt the structure of the 3R1 polytype. In the intermediate range of relative humidity values (40-60), the hydrated and dehydrated phases coexist. The end members of the hydration cycle adopt the structure of the same polytype, and vary only in their basal spacings. This points to the possibility that all the intermediate phases have a kinetic origin. © 2013 Elsevier Inc
Genotype List String: a grammar for describing HLA and KIR genotyping results in a text string
Knowledge of an individual's human leukocyte antigen (HLA) genotype is essential for modern medical genetics, and is crucial for hematopoietic stem cell and solid-organ transplantation. However, the high levels of polymorphism known for the HLA genes make it difficult to generate an HLA genotype that unambiguously identifies the alleles that are present at a given HLA locus in an individual. For the last 20 years, the histocompatibility and immunogenetics community has recorded this HLA genotyping ambiguity using allele codes developed by the National Marrow Donor Program (NMDP). While these allele codes may have been effective for recording an HLA genotyping result when initially developed, their use today results in increased ambiguity in an HLA genotype, and they are no longer suitable in the era of rapid allele discovery and ultra-high allele polymorphism. Here, we present a text string format capable of fully representing HLA genotyping results. This Genotype List (GL) String format is an extension of a proposed standard for reporting killer-cell immunoglobulin-like receptor (KIR) genotype data that can be applied to any genetic data that use a standard nomenclature for identifying variants. The GL String format uses a hierarchical set of operators to describe the relationships between alleles, lists of possible alleles, phased alleles, genotypes, lists of possible genotypes, and multilocus unphased genotypes, without losing typing information or increasing typing ambiguity. When used in concert with appropriate tools to create, exchange, and parse these strings, we anticipate that GL Strings will replace NMDP allele codes for reporting HLA genotypes
Superconductivity-Induced Anomalies in the Spin Excitation Spectra of Underdoped YBa_2 Cu_3 O_{6+x}
Polarized and unpolarized neutron scattering has been used to determine the
effect of superconductivity on the magnetic excitation spectra of YBa_2 Cu_3
O_{6.5} (T_c = 52K) and YBa_2 Cu_3 O_{6.7} (T_c = 67K). Pronounced enhancements
of the spectral weight centered around 25 meV and 33 meV, respectively, are
observed below T_c in both crystals, compensated predominantly by a loss of
spectral weight at higher energies. The data provide important clues to the
origin of the 40 meV magnetic resonance peak in YBa_2 Cu_3 O_7.Comment: LaTex, 4 pages, 4 ps figures. to appear in Phys. Rev. Let
Neuropsychological Findings in Idiopathic Adult-Onset Epilepsy Case Study: Noorda COM Student Investigation
We report the case of a 25-year-old male patient with idiopathic adult-onset epilepsy. The patient presented with a chief complaint of recurrent seizures and no identifiable cause. These seizures were associated with a lack of extremity control, muscle spasms, and loss of cognitive function. His condition began while living in Thailand, where he experienced multiple environmental stressors including hostile living conditions and tense situations, approximately five years before being seen in the clinic. Over the past several years, the seizures have not ceased, and the patient now notes a loss or decrease of several special senses
Spin Susceptibility in Underdoped
We report a comprehensive polarized and unpolarized neutron scattering study
of the evolution of the dynamical spin susceptibility with temperature and
doping in three underdoped single crystals of the \YBCO{6+x} high temperature
superconductor: \YBCO{6.5} (Tc = 52 K), \YBCO{6.7} (Tc = 67 K), and \YBCO{6.85}
(T_c = 87 K). Theoretical implications of these data are discussed, and a
critique of recent attempts to relate the spin excitations to the
thermodynamics of high temperature superconductors is given.Comment: minor revisions, to appear in PR
Sr<sub>2</sub>Li[Fe<sub>2</sub>N<sub>3</sub>] und Ba<sub>2</sub>Li[Fe<sub>2</sub>N<sub>3</sub>]: Isotype Nitridoferrate(II) mit <sup>1</sup>∞[(FeN<sub>3/2</sub>)<sub>2</sub><sup>5Θ</sup>]-Anionen
Eine enge strukturelle Verwandtschaft zum formal isoelektronischen B2S3 zeichnet den polymeren Anionenverband der Titelverbindungen aus. Dieser besteht aus Fe2N2-Ringen, die über gemeinsame exocyclische N-Atome zu Ketten verknüpft und in denen die FeII-Zentren verzerrt trigonal-planar koordiniert sind (Strukturbild unten: • = Fe, O = N)
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