Spontaneous in-flight assembly of magnetic nanoparticles into macroscopic chains.

Knowing the interactions controlling aggregation processes in magnetic nanoparticles is of strong interest in preventing or promoting nanoparticles' aggregation at wish for different applications. Dipolar magnetic interactions, proportional to the particle volume, are identified as the key driving force behind the formation of macroscopic aggregates for particle sizes above about 20 nm. However, aggregates' shape and size are also strongly influenced by topological ordering.

Rare earth activated yttrium aluminate phosphors with modulated luminescence.

Yttrium aluminate (Y3 A5 O12 ) was doped with different rare earth ions (i.e. Gd(3+) , Ce(3+) , Eu(3+) and/or Tb(3+) ) in order to obtain phosphors (YAG:RE) with general formula,Y3-x-a Gdx REa Al5 O12 (x = 0; 1.

The Chiari Symptom Profile: development and validation of a Chiari-/syringomyelia-specific questionnaire.

Objective: The Chiari Symptom Profile (CSP) was developed to provide a quantitative assessment of self-reported Chiari (CMI)-related symptoms and their impact on the individual's quality of life.

Methods: The instrument was developed in three phases. Phase I consisted of instrument development using exploratory item analysis from the literature and direct patient evaluations.

Posterior fossa decompression and reconstruction in adolescents and adults with the Chiari I malformation.

Objective: The purpose of this paper is to review the current and historical surgical approaches to treating Chiari I malformation in adolescents and adults.

Methods: A PubMed literature review and the author's own surgical experiences serve as a basis for discussing the variability in the surgical treatment of the Chiari I malformation.

Results: The most common treatment of the Chiari I malformation is posterior fossa decompression, which can range from a minimally invasive extradural approach to durotomy, duraplasty, internal decompression, and cranioplasty.

Single crystalline La0.7Sr0.3MnO3 molecular sieve nanowires with high temperature ferromagnetism.

Porous mixed-valent manganese oxides are a group of multifunctional materials that can be used as molecular sieves, catalysts, battery materials, and gas sensors. However, material properties and thus activity can vary significantly with different synthesis methods or process conditions, such as temperature and time. Here, we report on a new synthesis route for MnO(2) and LaSr-doped molecular sieve single crystalline nanowires based on a solution chemistry methodology combined with the use of nanoporous polymer templates supported on top of single crystalline substrates.

Relaxometric and magnetic characterization of ultrasmall iron oxide nanoparticles with high magnetization. Evaluation as potential T1 magnetic resonance imaging contrast agents for molecular imaging.

Here we report on the synthesis of ultrasmall gamma-Fe2O3 nanoparticles (5 nm) presenting a very narrow particle size distribution and an exceptionally high saturation magnetization. The synthesis has been carried out by decomposition of an iron organometallic precursor in an organic medium. The particles were subsequently stabilized in an aqueous solution at physiological pH, and the colloidal dispersions have been thoroughly characterized by complementary techniques.

Phenotypic definition of Chiari type I malformation coupled with high-density SNP genome screen shows significant evidence for linkage to regions on chromosomes 9 and 15.

Chiari type I malformation (CMI; OMIM 118420) is narrowly defined when the tonsils of the cerebellum extend below the foramen magnum, leading to a variety of neurological symptoms. It is widely thought that a small posterior fossa (PF) volume, relative to the total cranial volume leads to a cramped cerebellum and herniation of the tonsils into the top of the spinal column. In a collection of magnetic resonance imagings (MRIs) from affected individuals and their family members, we measured correlations between ten cranial morphologies and estimated their heritability in these families.

Arachnoid cyst resulting in tonsillar herniation and syringomyelia in a patient with achondroplasia. Case report.

Achondroplasia has been associated with varying degrees of cervicomedullary and spinal compression, although usually in the pediatric population. Large arachnoid cysts have also been found to result in tonsillar herniation and syringomyelia. The authors present the case of a patient with achondroplasia who presented with symptoms of foramen magnum compression and syringomyelia, and who was subsequently found to have a large posterior fossa arachnoid cyst.

Protective antigen and toxin neutralization antibody patterns in anthrax vaccinees undergoing serial plasmapheresis.

Recipients of licensed anthrax vaccine (AVA; Biothrax) could serve as a source of hyperimmune plasma and immunoglobulin for therapy and prophylaxis. We measured serum antibodies during serial weekly to biweekly plasmapheresis in 38 individuals previously vaccinated with 4 to 27 doses of AVA. Immunoglobulin G (IgG) to protective antigen (PA) and toxin neutralization assay (TNA) antibody levels were highly correlated (r = 0.

Chiari I malformation with or without syringomyelia and pregnancy: case studies and review of the literature.

Women with Chiari I malformation with or without syringomyelia are of particular concern because of the potential risk of increased intracranial pressure during pregnancy and delivery. The following questions are most often asked in the clinical setting: Is it safe to have a planned pregnancy? Will the symptoms become worse or recur during pregnancy and will the baby be normal? Seven patients with Chiari I malformation, with and without syringomyelia, submitted checklists of self-reported symptoms experienced during pregnancy, labor, and postpartum. Seven patients with Chiari I malformation with and without syringomyelia were queried for symptoms during pregnancy, labor, and postpartum.

Prospective analysis of self-perceived quality of life before and after posterior fossa decompression in 112 patients with Chiari malformation with or without syringomyelia.

Object: The purpose of this prospective study was to determine if there was a difference in the self-perceived quality of life (QOL) before and after surgery among patients with Chiari I malformations with or without syringomyelia. Most patients with Chiari I malformations report improvement in their QOL after decompression surgery; however, specific outcome data have not been empirically studied in this patient population.

Methods: One hundred seventy-two consecutive patients who underwent posterior fossa decompression based on neuroimaging evidence of a Chiari I malformation with or without syringomyelia were prospectively offered participation in the study.

Evolution of the brain: from behavior to consciousness in 3.4 billion years.

Once life began as single-cell organisms, evolution favored those able to seek nutrients and avoid risks. Receptors sensed the environment, memory traces were laid, and adaptive responses were made. Environmental stress, at times as dramatic as the collision of an asteroid, resulted in extinctions that favored small predators with dorsal nerve cords and cranially positioned brains.

Prospective analysis of presenting symptoms among 265 patients with radiographic evidence of Chiari malformation type I with or without syringomyelia.

Objective: To characterize the presenting symptoms among persons with radiographic evidence of Chiari malformation (CM) type I in an effort to help the primary care provider determine accurate diagnosis and treatment.

Methods: The symptoms of CM can often be vague and ambiguous, leading to misdiagnosis. Patients who had radiographic evidence of CM with or without syringomyelia were prospectively studied.

Determination of death by neurological criteria.

Until 1968, when an ad hoc Harvard Medical School Committee published a landmark paper calling for determination of death using neurological rather than cardiovascular criteria, death was considered to have occurred when the heart irreversibly ceased beating. Since that time, every jurisdiction in the country has come to accept through law or court decision neurological criteria to define death. The authors review the issue of death by neurological criteria in light of current guidelines and recent advances.

[Treatment with desmopressin before epidural anesthesia in a patient with type I von Willebrand disease].

A 33-year-old primipara with von Willebrand disease type I was admitted in labor at 37 weeks, requesting epidural analgesia. The consultant hematologist advised treating with desmopressin acetate (DDAVP) before inserting an epidural catheter. Desmopressin at a dose of 0.

Primary sources of phosphorus and phosphates in chemical evolution.

In this work we consider the role of phosphorus in chemical evolution from an interdisciplinary approach. First we briefly review the presence of this element in different cosmic sites, such as massive stellar cores, circumstellar and interstellar clouds, meteorites, lunar and Martian samples, interplanetary dust particles, cometary dust and planetary atmospheres. Thus we illustrate the fact that phosphorus seems to be, at the same time, scarce and ubiquitous in the solar system.

Decompressive craniotomy in medically uncontrollable malignant infarction.

Patients with progressive neurological deficit following large cerebral infarctions are viewed to have a uniformly poor prognosis. We present two patients with large middle cerebral artery infarctions in which a decompressive craniotomy was life saving and resulted in functional outcome. The clinical course of patients with malignant infarction and the treatment issues involved including patient selection and the timing and extent of cranial decompression are discussed.

Production of guanine from NH(4)CN polymerizations.

The synthesis of adenine from the polymerization of concentrated ammonium cyanide solutions is well known. We show here that guanine is also produced by this reaction but at yields ranging from 10 to 40 times less than that of adenine. This synthesis is effective at both +80 and -20 degrees C.

Balloon device for experimental graded spinal cord compression in the rat.

We have developed a balloon device that creates reproducible graded compression of the rat spinal cord. It uses a modified Camino intracranial pressure monitor bolt with a small latex balloon attached to the tip. The device is affixed to the spinous processes of two cervicothoracic vertebrae and positioned directly over an exposed segment of spinal cord.

Experience with transcranial magnetic stimulation in cortical mapping.

Seventeen subjects underwent transcranial magnetic stimulation (TMS) toward cortical mapping. Cortical mapping produced scalp representations of five upper extremity muscles, and their spatial orientation tended to support an expected anatomic pattern. Muscle map locations and map areas showed trends across musical skill and hand dominance, as well.

Suppression of spinal and cortical somatosensory evoked potentials by desflurane anesthesia.

The effect of the volatile anesthetic desflurane on spinal and cortical somatosensory evoked potentials (SEPs) was examined in 11 Sprague-Dawley male rats. Platinum recording electrodes were placed stereotactically over the left somatosensory cortex and dorsal midline of the T11-12 spinal cord while the right posterior tibial nerve was stimulated at twice motor threshold. The effect of desflurane was examined at various concentrations ranging from 0.

Neurophysiological evidence of spared upper motor neurons after spinal cord injury.

Fourteen cats were subjected to a moderate (100 gm-cm; n = 7) or a severe (600 gm-cm; n = 7) spinal cord injury at the C4-C5 level using a weight drop technique. Somatosensory evoked potentials (SSEPs) were recorded after stimulation of the median nerve in the forearm. The SSEPs were measured in each animal before and after the injury.

Effect of desflurane anesthesia on transcortical motor evoked potentials.

The effect of the volatile anesthetic desflurane on motor evoked potentials was examined in male rats. Animals underwent cortical stimulation using small platinum ball stimulating electrodes secured on the motor cortex. To record evoked compound muscle action potentials (CMAPs), single-shock electrical stimulation was delivered to the forelimb representation of the motor cortex.