Utilizing infrared vibrational spectroscopy we have investigated dimerized two-dimensional organic salts in order to search for possible charge redistribution that might constitute electronic dipoles and ferroelectricity: the quantum spin liquid κ-(BEDT-TTF) 2 Cu 2 (CN) 3 [BEDT-TTF: bis-(ethylenedithio)tetrathiafulvalene], the antiferromagnetic Mott insulator κ-(BEDT-TTF) 2 Cu[N(CN) 2 ]Cl, and the superconductor κ-(BEDT-TTF) 2 Cu[N(CN) 2 ]Br. None of them exhibit any indication of charge disproportionation. Upon cooling to low temperatures all BEDT-TTF molecules remain homogeneously charged within ±0.005e. No modification in the charge distribution is observed around T = 6 K where a low-temperature anomaly has been reported for the spin-liquid material κ-(BEDT-TTF) 2 Cu 2 (CN) 3 . In this compound the in-plane optical response and vibrational coupling are rather anisotropic, indicating that the tilt of the BEDT-TTF molecules in c direction and their coupling to the anion layers has to be considered in the explanation of the electromagnetic properties.

We measured the optical reflectivity of [001]-oriented n-doped Cd3As2 in a broad frequency range (50 -22 000 cm −1 ) for temperatures from 10 to 300 K. The optical conductivity, σ(ω) = σ1(ω) + iσ2(ω), is isotropic within the (001) plane; its real part follows a power law, σ1(ω) ∝ ω 1.65 , in a large interval from 2000 to 8000 cm −1 . This behavior is caused by interband transitions between two Dirac bands, which are effectively described by a sublinear dispersion relation, E(k) ∝ |k| 0.6 . The momentum-averaged Fermi velocity of the carriers in these bands is energy dependent and ranges from 1.2 × 10 5 to 3 × 10 5 m/s, depending on the distance from the Dirac points. We detect a gaplike feature in σ1(ω) and associate it with the Fermi level positioned around 100 meV above the Dirac points.

This study was performed with the aim of determining the diagnostic profile of newborns with hypotonia and of analyzing the usefulness of different procedures in the diagnostic process. One hundred thirty-eight hypotonic newborns were identified through the search of hospital records in a 10-year period: 121 (88%) had central hypotonia and 13 (9%) had peripheral hypotonia, whereas 4 (3%) remained unclassified. Analysis of the contribution of clinical data and results of investigations led to the construction of an algorithm, by which all cases in the group were diagnosed. Step 1, which included clinical data and results of examinations, solved 50% of all diagnosed cases. Neuroimaging techniques made up step 2 and contributed to the diagnosis in 13%. Step 3 was accomplished by a search through Oxford Medical Databases, which yielded the final diagnosis in 9%, whereas karyotyping and fluorescent in situ hybridization for Prader-Willi syndrome comprised step 4 and contributed to the diagnosis in 6.5%. Biochemical tests formed step 5 and contributed to the diagnosis in 6%. Step 6, which included specific investigations of muscle and nerve, was diagnostic in 6%. The remaining cases (6.5%) were diagnosed only after several follow-up examinations. These results could assist the neonatologist when deciding the diagnostic approach to floppy newborns.

Our comprehensive study on EuFe_{2}As_{2} reveals a dramatic reduction of magnetic detwinning fields compared to other AFe_{2}As_{2} (A=Ba, Sr, Ca) iron pnictides by indirect magnetoelastic coupling of the Eu^{2+} ions. We find that only ∼0.1  T are sufficient for persistent detwinning below the local Eu^{2+} ordering; above T_{Eu}=19  K, higher fields are necessary. Even after the field is switched off, a significant imbalance of twin domains remains constant up to the structural and electronic phase transition (190 K). This persistent detwinning provides the unique possibility to study the low temperature electronic in-plane anisotropy of iron pnictides without applying any symmetry-breaking external force.

Background Joubert syndrome (JS) is a recessive ciliopathy characterized by a distinctive brain malformation “the molar tooth sign”. Mutations in >27 genes cause JS, and mutations in 12 of these genes also cause Meckel syndrome (MKS). The goals of this work are to describe the clinical features of MKS1-related JS and determine whether disease causing MKS1 mutations affect cellular phenotypes such as cilium number, length and protein content as potential mechanisms underlying JS. Methods We measured cilium number, length and protein content (ARL13B and INPP5E) by immunofluorescence in fibroblasts from individuals with MKS1-related JS and in a 3D spheroid rescue assay to test the effects of disease-related MKS1 mutations. Results We report MKS1 mutations (eight of them previously unreported) in nine individuals with JS. A minority of the individuals with MKS1-related JS have MKS features. In contrast to the truncating mutations associated with MKS, all of the individuals with MKS1-related JS carry ≥1 non-truncating mutation. Fibroblasts from individuals with MKS1-related JS make normal or fewer cilia than control fibroblasts, their cilia are more variable in length than controls, and show decreased ciliary ARL13B and INPP5E. Additionally, MKS1 mutant alleles have similar effects in 3D spheroids. Conclusions MKS1 functions in the transition zone at the base of the cilium to regulate ciliary INPP5E content, through an ARL13B-dependent mechanism. Mutations in INPP5E also cause JS, so our findings in patient fibroblasts support the notion that loss of INPP5E function, due to either mutation or mislocalization, is a key mechanism underlying JS, downstream of MKS1 and ARL13B.