882 research outputs found
^{63}Cu, ^{35}Cl, and ^{1}H NMR in the S=1/2 Kagom\'e Lattice ZnCu_{3}(OH)_{6}Cl_{2}
ZnCu(OH)Cl () is a promising new candidate for an
ideal Kagom\'e Heisenberg antiferromagnet, because there is no magnetic phase
transition down to 50 mK. We investigated its local magnetic and lattice
environments with NMR techniques. We demonstrate that the intrinsic local spin
susceptibility {\it decreases} toward T=0, but that slow freezing of the
lattice near 50 K, presumably associated with OH bonds, contributes to a
large increase of local spin susceptibility and its distribution. Spin dynamics
near T=0 obey a power-law behavior in high magnetic fields.Comment: Phys. Rev. Lett. (in press
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The F220C and F45L rhodopsin mutations identified in retinitis pigmentosa patients do not cause pathology in mice.
Retinitis pigmentosa is a retinal degenerative disease that leads to blindness through photoreceptor loss. Rhodopsin is the most frequently mutated protein in this disease. While many rhodopsin mutations have well-understood consequences that lead to cell death, the disease association of several rhodopsin mutations identified in retinitis pigmentosa patients, including F220C and F45L, has been disputed. In this study, we generated two knockin mouse lines bearing each of these mutations. We did not observe any photoreceptor degeneration in either heterozygous or homozygous animals of either line. F220C mice exhibited minor disruptions of photoreceptor outer segment dimensions without any mislocalization of outer segment proteins, whereas photoreceptors of F45L mice were normal. Suction electrode recordings from individual photoreceptors of both mutant lines showed normal flash sensitivity and photoresponse kinetics. Taken together, these data suggest that neither the F220C nor F45L mutation has pathological consequences in mice and, therefore, may not be causative of retinitis pigmentosa in humans
Brief of Amici Curiae Constitutional Law Scholars In Support Of Petitioners
“[I]n a complex society and an era of pervasive governmental regulation, defining the proper realm for free exercise can be difficult.” Burwell v. Hobby Lobby Stores, Inc., 134 S. Ct. 2751, 2781, 2785 (2014) (Kennedy, J., concurring). The Religious Freedom Restoration Act (“RFRA”)2 addresses that difficulty by harmonizing religious freedom and the interests of third parties. RFRA will not exempt free exercise from a law’s command simply because the law substantially burdens religion—nor will it deny a religious exemption simply because the exemption would affect a third party
Brief of Amici Curiae Constitutional Law Scholars In Support Of Petitioners
“[I]n a complex society and an era of pervasive governmental regulation, defining the proper realm for free exercise can be difficult.” Burwell v. Hobby Lobby Stores, Inc., 134 S. Ct. 2751, 2781, 2785 (2014) (Kennedy, J., concurring). The Religious Freedom Restoration Act (“RFRA”)2 addresses that difficulty by harmonizing religious freedom and the interests of third parties. RFRA will not exempt free exercise from a law’s command simply because the law substantially burdens religion—nor will it deny a religious exemption simply because the exemption would affect a third party
Dynamic Scaling in the Susceptibility of the Spin-1\2 Kagome Lattice Antiferromagnet Herbertsmithite
The spin-1/2 kagome lattice antiferromagnet herbertsmithite,
ZnCu(OH)Cl, is a candidate material for a quantum spin liquid
ground state. We show that the magnetic response of this material displays an
unusual scaling relation in both the bulk ac susceptibility and the low energy
dynamic susceptibility as measured by inelastic neutron scattering. The
quantity with can be expressed as a
universal function of or . This scaling is discussed in
relation to similar behavior seen in systems influenced by disorder or by the
proximity to a quantum critical point.Comment: 5 pages, 3 figures v2: updated to match published version
The effects of mineral microparticles on dental cell differentiation
With the progression of regenerative medicine, bio-fillers are becoming a very viable option in the treatment of dental caries and the repair ofcranio-facial injuries.Manyprevious studies have focused onthe use ofbone marrow stem cells (BMSCs) with micro-Hydroxyapatite (HA) particles. However, there have been mixed reports on these particles having positive or negative effects on cells. This work delves into the effects of micro-HA on BMSCs, 7F2 osteoblasts, and dental pulp stem cells (DPSCs) as well as the effects of micro-Fluorapatite (FA) on these cells.ALP and BCA assays were run for 14 days on to determine ALP specific activity and protein content. Antibody stains andconfocalimaging were done for collagenI and osteocalcin. Control cells produced more protein, osteocalcin, and collagen I, and had higher levels ofALP specific activitywith the exception ofa few spikes in each for cells cultured with microparticles
Crosstalk in the mouse thymus
The development of mature T cells within the thymus is dependent upon intact cortical and medullary microenvironments. In turn, thymic microenvironment themselves are dependent on lymphoid cells to maintain their integrity. Here, Willem van Ewijk and colleagues discuss experiments that have established the phenomenon of ‘crosstalk’ within the mouse thymus and suggest a mechanism whereby lymphoid and stromal cells influence each other in a consecutive manner during T-cell development
Vesignieite BaCu3V2O8(OH)2 as a Candidate Spin-1/2 Kagome Antiferromagnet
A polycrystalline sample of vesignieite BaCu3V2O8(OH)2 comprising a nearly
ideal kagome lattice composed of Cu2+ ions carrying spin 1/2 has been
synthesized and studied by magnetization and heat capacity measurements.
Magnetic susceptibility shows a neither long range order, a spin glass
transition nor a spin gap down to 2 K, in spite of a moderately strong
antiferromagnetic interaction of J/kB = 53 K between nearest-neighbor spins. A
broad peak observed at a temperature corresponding to 0.4J in intrinsic
magnetic susceptibility indicates a marked development of the short-range
order. The ground state of vesignieite is probably a gapless spin liquid or is
accompanied by a very small gap less than J/30.Comment: 4 pages, 5 figure
Spin Dynamics of the Spin-1/2 Kagome Lattice Antiferromagnet ZnCu_3(OH)_6Cl_2
We have performed thermodynamic and neutron scattering measurements on the
S=1/2 kagome lattice antiferromagnet Zn Cu_3 (OH)_6 Cl_2. The susceptibility
indicates a Curie-Weiss temperature of ~ -300 K; however, no magnetic order is
observed down to 50 mK. Inelastic neutron scattering reveals a spectrum of low
energy spin excitations with no observable gap down to 0.1 meV. The specific
heat at low-T follows a power law with exponent less than or equal to 1. These
results suggest that an unusual spin-liquid state with essentially gapless
excitations is realized in this kagome lattice system.Comment: 4 pages, 3 figures; v2: Updates to authors list and references; v3:
Updated version; v4: Published versio
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