ab-plane resistivity and possible charge stripe ordering in strongly underdoped La2−x_{2-x}Srx_{x}CuO4_{4} single crystals

We have measured the ab-plane resistivity of La$_{2-x}$Sr$_x$CuO$_4$ single crystals with small Sr content (x=0.052 $\div$ 0.075) between 4.2 and 300 K by using the AC Van der Pauw technique. As recently suggested by Ichikawa et al., the deviation from the linearity of the $\rho_{\mathrm{ab}}(T)$ curve starting at a temperature T$_{\mathrm{ch}}$ can be interpreted as due to a progressive slowing down of the fluctuations of pre-formed charge stripes. An electronic transition of the stripes to a more ordered phase could instead be responsible for some very sharp anomalies present in the $\rho_{\mathrm{ab}}(T)$ of superconducting samples just above $T_{\mathrm{c}}$.Comment: M2S-HTSC-VI Conference paper (2 pages, 2 figures), using Elsevier style espcrc2.st

Synaptic dysfunction, memory deficits and hippocampal atrophy due to ablation of mitochondrial fission in adult forebrain neurons

Well-balanced mitochondrial fission and fusion processes are essential for nervous system development. Loss of function of the main mitochondrial fission mediator, dynamin-related protein 1 (Drp1), is lethal early during embryonic development or around birth, but the role of mitochondrial fission in adult neurons remains unclear. Here we show that inducible Drp1 ablation in neurons of the adult mouse forebrain results in progressive, neuronal subtype-specific alterations of mitochondrial morphology in the hippocampus that are marginally responsive to antioxidant treatment. Furthermore, DRP1 loss affects synaptic transmission and memory function. Although these changes culminate in hippocampal atrophy, they are not sufficient to cause neuronal cell death within 10 weeks of genetic Drp1 ablation. Collectively, our in vivo observations clarify the role of mitochondrial fission in neurons, demonstrating that Drp1 ablation in adult forebrain neurons compromises critical neuronal functions without causing overt neurodegeneration

Granulocytic sarcoma in a non-leukemic patient presenting with unusual cutaneous paraneoplastic syndrome.

40-year old man was admitted to our Institute because of an erythematous, exfoliative dermatitis, along with a gross right leg and scrotal edema. Histologic examination of the skin biopsy was consistent with a diagnosis of acquired ichthyosis (Figure 1). A total body computed tomography documented the presence of a voluminous mass in the right iliac fossa (Figure 2). Histologic, histochemical and immunohistochemical examinations of a CT-guided biopsy (Figures 3-4) were consistent with the diagnosis of granulocytic sarcoma.1 Support therapy was started, but after 8 days the patient die

Thermochemistry of YBa(2)Cu(3-x)M(x)O(y) (M=Ni,Zn)

Many studies have investigated the behavior of transition metal dopants in the YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} 123 superconductors. Much of this research has focused on the effects of metal ions such as Co, Fe, Zn, Ni when they are substituted for the copper ions at Cu(1) and Cu(2) sites, commonly referred to as the chain and plane sites, respectively. Trivalent ions such as Co{sup +3} and Fe{sup +3}have been shown to behave similarly in their substitution effects, displaying site preference on the Cu(1) site [3-8]. This site preference has been established with the use of techniques such as neutron diffraction and Moessbauer spectroscopy [4,5]. Thermogravimetry, electron diffraction, and analysis of lattice parameters as a function of dopant also yield results consistent with those of the structural studies with respect to the chain site preference of both Co and Fe [3,4,6-8]. The very fast convergence of a and b lattice parameters to that of the tetragonal structure, occurring at x = 0.3 Co dopant (i.e. YBa{sub 2}Cu{sub 2.7}Co{sub 0.3}O{sub 7{minus}{delta}}) for high-oxygen-content samples, coupled with information derived from diffuse scattering and oxidation behavior of these samples, has been described in detail by several authors in terms of the Co and Fe ions creating ''microchains'' at Cu(1) sites within the 123 compound [4,7-8]. The Cu(1) site dopants decrease T{sub c} at a rate of 2 to 5 K/at. %, varying to some extent with site preference [4,9]