Kondo screening in d-wave superconductors in a Zeeman field and implications for STM spectra of Zn-doped cuprates

We consider the screening of an impurity moment in a d-wave superconductor under the influence of a Zeeman magnetic field. Using the Numerical Renormalization Group technique, we investigate the resulting pseudogap Kondo problem, in particular the field-induced crossover behavior in the vicinity of the zero-field boundary quantum phase transition. The impurity spectral function and the resulting changes in the local host density of states are calculated, giving specific predictions for high-field STM measurements on impurity-doped cuprates.Comment: 5 pages, 4 figs, (v2) remark on c-axis field added, discussion extended, (v3) final version as publishe

Persistence of Li Induced Kondo Moments in the Superconducting State of Cuprates

We measure the magnetic susceptibility nearby Li spinless impurities in the superconducting phase of the high Tc cuprate YBaCuO. The induced moment which was found to exist above Tc persists below Tc. In the underdoped regime, it retains its Curie law below Tc. In contrast, near optimal doping, the large Kondo screening observed above Tc (T_K=135 K) is strongly reduced below Tc as expected theoretically when the superconducting gap develops. This moment still extends essentially on its 4 near neighbour Cu, showing the persistence of AF correlations in the superconducting state. A direct comparison with recent STM results of Pan et al. is proposed.Comment: accepted for publication in Phys. Rev. Lett. (issue of 30 april 2001) Revised version : 8 pages including 4 pages of text and 4 figure

Specific Heat of Zn-Doped YBa_{2}Cu_3O_{6.95}: Possible Evidence for Kondo Screening in the Superconducting State

The magnetic field dependence of the specific heat of Zn-doped single crystals of YBa_{2}Cu_3O_{6.95} was measured between 2 and 10 K and up to 8 Tesla. Doping levels of 0, 0.15%, 0.31%, and 1% were studied and compared. In particular we searched for the Schottky anomaly associated with the Zn-induced magnetic moments.Comment: 5 pages, 6 figure

Dextran Penetration Through Nonkeratinized and Keratinized Epithelia in Monkeys

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142019/1/jper0424.pd

Impurity in a d-wave superconductor: Kondo effect and STM spectra

We present a theory for recent STM studies of Zn impurities in the superconductor BSCCO, using insights from NMR experiments which show that there is a net S=1/2 moment on the Cu ions near the Zn. We argue that the Kondo spin dynamics of this moment is the origin of the low bias peak in the differential conductance, rather than a resonance in a purely potential scattering model. The spatial and energy dependence of the STM spectra of our model can also fit the experiments.Comment: 4 pages, 2 color figures. Found improved saddle-point with d-wave correlations near the impurity; onset of Kondo screening now occurs at a significantly smaller coupling, but there is little qualitative change in other features. Noted connection to STM of Kondo impurities in normal metals. Final version as publishe

Surgical treatment of thyrotoxicosis in children and adolescents

Forty-one children and adolescents had thyroidectomies for Grave's disease during an 8 yr period. Twenty patients became euthyroid within a short period after treatment with antithyroid drugs and had operations with minimal disruption of their lives. Antithyroid drugs were administered to 20 patients for a longer period of time as a primary form of treatment for Grave's disease. Complications resulting from drug toxicity, poor cooperation by patients, and persistent goiters were indications for thyroidectomies in this group. Permanent remissions, after prolonged antithyroid drug therapy, are rare in children. Because the treatment is associated with significant morbidity, this form of therapy is unacceptable in most cases. Iodine-131 was given to 30 children or adolescents for Grave's disease during the same time period. Iodine-131 is primarily indicated for patients who are resistant or allergic to antithyroid drugs, who have serious systemic diseases, or who have had previous thyroid operations. Hypothyroidism is an inevitable result of effective 131I treatment of Grave's disease in children. Serious consequences from 131I therapy were not observed during the short period of follow-up. Subtotal thyroidectomy continues to be the preferred primary treatment for most patients with Grave's disease in childhood. Total thyroidectomy may be indicated for patients in the first decade of life. Hypothyroidism, which is easily managed in this age group, is the price paid for the prevention of recurrent Grave's disease. Early detection and treatment of hypothyroidism can be achieved only by a careful follow-up of all patients treated by less than total thyroidectomy for Grave's disease.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22804/1/0000361.pd

Toxicity from treatment of neuroblastoma with 131 I-meta-iodobenzylguanidine

Toxic effects from 131 I-meta-iodobenzylguanidine ( 131 I-MIBG) treatments of neuroblastoma in six patients were recorded. The toxicity was largely confined to the hematologic system where circulating leukocytes and platelets regularly declined after each dose of 131 I-MIBG; the values reached nadirs between three and seven weeks and recovered slowly over subsequent weeks. Prior bone marrow transplantation and infiltration of bone marrow by neuroblastoma appeared to make the hematologic system more vulnerable to the radiation. Dosimetry revealed greater absorbed radiation by the whole body than by the blood and bone marrow. These observations are explained by a relatively rapid exit of 131 I-MIBG from the blood to other tissues (but not to the bone marrow). Since treatment of an aggressive and lethal tumor such as neuroblastoma should be pushed to a degree of toxicity, careful dosimetry in each case will be necessary as a guide to reach the point of maximally tolerable toxicity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46827/1/259_2004_Article_BF00254379.pd

EquiFACS: the Equine Facial Action Coding System

Although previous studies of horses have investigated their facial expressions in specific contexts, e.g. pain, until now there has been no methodology available that documents all the possible facial movements of the horse and provides a way to record all potential facial configurations. This is essential for an objective description of horse facial expressions across a range of contexts that reflect different emotional states. Facial Action Coding Systems (FACS) provide a systematic methodology of identifying and coding facial expressions on the basis of underlying facial musculature and muscle movement. FACS are anatomically based and document all possible facial movements rather than a configuration of movements associated with a particular situation. Consequently, FACS can be applied as a tool for a wide range of research questions. We developed FACS for the domestic horse (Equus caballus) through anatomical investigation of the underlying musculature and subsequent analysis of naturally occurring behaviour captured on high quality video. Discrete facial movements were identified and described in terms of the underlying muscle contractions, in correspondence with previous FACS systems. The reliability of others to be able to learn this system (EquiFACS) and consistently code behavioural sequences was high—and this included people with no previous experience of horses. A wide range of facial movements were identified, including many that are also seen in primates and other domestic animals (dogs and cats). EquiFACS provides a method that can now be used to document the facial movements associated with different social contexts and thus to address questions relevant to understanding social cognition and comparative psychology, as well as informing current veterinary and animal welfare practices

Loss of ASP but not ROPN1 reduces mammalian ciliary motility

Protein kinase A (PKA) signaling is targeted by interactions with A-kinase anchoring proteins (AKAPs) via a dimerization/docking domain on the regulatory (R) subunit of PKA. Four other mammalian proteins (ASP, ROPN1, SP17, and CABYR) share this highly conserved RII dimerization/docking (R2D2) domain. ASP and ROPN1 are 41% identical in sequence, interact with a variety of AKAPs in a manner similar to PKA, and are expressed in ciliated and flagellated human cells. To test the hypothesis that these proteins regulate motility, we developed mutant mouse lines lacking ASP or ROPN1. Both mutant lines produced normal numbers of cilia with intact ciliary ultrastructure. Lack of ROPN1 had no effect on ciliary motility. However, the beat frequency of cilia from mice lacking ASP is significantly slower than wild type, indicating that ASP signaling may regulate ciliary motility. This is the first demonstration of in vivo function for ASP. Similar localization of ASP in mice and humans indicates that these findings may translate to human physiology, and that these mice will be an excellent model for future studies related to the pathogenesis of human disease

Order and quantum phase transitions in the cuprate superconductors

It is now widely accepted that the cuprate superconductors are characterized by the same long-range order as that present in the Bardeen-Cooper-Schrieffer (BCS) theory: that associated with the condensation of Cooper pairs. We argue that many physical properties of the cuprates require interplay with additional order parameters associated with a proximate Mott insulator. We review a classification of Mott insulators in two dimensions, and contend that the experimental evidence so far shows that the class appropriate to the cuprates has collinear spin correlations, bond order, and confinement of neutral, spin S=1/2 excitations. Proximity to second-order quantum phase transitions associated with these orders, and with the pairing order of BCS, has led to systematic predictions for many physical properties. We use this context to review the results of recent neutron scattering, fluxoid detection, nuclear magnetic resonance, and scanning tunnelling microscopy experiments.Comment: 20 pages, 13 figures, non-technical review article; some technical details in the companion review cond-mat/0211027; (v3) added refs; (v4) numerous improvements thanks to the referees, to appear in Reviews of Modern Physics; (v6) final version as publishe