Magnetization vector manipulation by electric fields.

Conventional semiconductor devices use electric fields to control conductivity, a scalar quantity, for information processing. In magnetic materials, the direction of magnetization, a vector quantity, is of fundamental importance. In magnetic data storage, magnetization is manipulated with a current-generated magnetic field (Oersted-Ampère field), and spin current is being studied for use in non-volatile magnetic memories. To make control of magnetization fully compatible with semiconductor devices, it is highly desirable to control magnetization using electric fields. Conventionally, this is achieved by means of magnetostriction produced by mechanically generated strain through the use of piezoelectricity. Multiferroics have been widely studied in an alternative approach where ferroelectricity is combined with ferromagnetism. Magnetic-field control of electric polarization has been reported in these multiferroics using the magnetoelectric effect, but the inverse effect-direct electrical control of magnetization-has not so far been observed. Here we show that the manipulation of magnetization can be achieved solely by electric fields in a ferromagnetic semiconductor, (Ga,Mn)As. The magnetic anisotropy, which determines the magnetization direction, depends on the charge carrier (hole) concentration in (Ga,Mn)As. By applying an electric field using a metal-insulator-semiconductor structure, the hole concentration and, thereby, the magnetic anisotropy can be controlled, allowing manipulation of the magnetization direction.

Direct k-space mapping of the electronic structure in an oxide-oxide interface.

The interface between LaAlO(3) and SrTiO(3) hosts a two-dimensional electron system of itinerant carriers, although both oxides are band insulators. Interface ferromagnetism coexisting with superconductivity has been found and attributed to local moments. Experimentally, it has been established that Ti 3d electrons are confined to the interface. Using soft x-ray angle-resolved resonant photoelectron spectroscopy we have directly mapped the interface states in k space. Our data demonstrate a charge dichotomy. A mobile fraction contributes to Fermi surface sheets, whereas a localized portion at higher binding energies is tentatively attributed to electrons trapped by O vacancies in the SrTiO(3). While photovoltage effects in the polar LaAlO(3) layers cannot be excluded, the apparent absence of surface-related Fermi surface sheets could also be fully reconciled in a recently proposed electronic reconstruction picture where the built-in potential in the LaAlO(3) is compensated by surface O vacancies serving also as a charge reservoir.

Spatially homogeneous ferromagnetism of (Ga, Mn)As.

Mn-doped GaAs is a ferromagnetic semiconductor, widely studied because of its possible application for spin-sensitive 'spintronics' devices. The material also attracts great interest in fundamental research regarding its evolution from a paramagnetic insulator to a ferromagnetic metal. The high sensitivity of its physical properties to preparation conditions and heat treatments and the strong doping and temperature dependencies of the magnetic anisotropy have generated a view in the research community that ferromagnetism in (Ga, Mn)As may be associated with unavoidable and intrinsic strong spatial inhomogeneity. Muon spin relaxation (muSR) probes magnetism, yielding unique information about the volume fraction of regions having static magnetic order, as well as the size and distribution of the ordered moments. By combining low-energy muSR, conductivity and a.c. and d.c. magnetization results obtained on high-quality thin-film specimens, we demonstrate here that (Ga, Mn)As shows a sharp onset of ferromagnetic order, developing homogeneously in the full volume fraction, in both insulating and metallic films. Smooth evolution of the ordered moment size across the insulator-metal phase boundary indicates strong ferromagnetic coupling between Mn moments that exists before the emergence of fully itinerant hole carriers.

Haemophilia A in a female mixed-breed dog.

A spayed female mixed-breed dog was presented with excessive bleeding from a wound in the mouth. The dog had a history of self-limiting bleeding following ovariohysterectomy. A coagulation test revealed prolongation of the activated partial thromboplastin time (20.2 seconds; reference interval: 11.0-15.0 seconds), prothrombin time was normal and factor VIII activity was markedly decreased (1.9%; reference interval: >50%). The von Willebrand factor antigen concentration was 158% (reference interval: >50%). A cross-mixing test indicated that the diminished factor VIII activity was due to deficiency or dysfunction of factor VIII rather than inhibition of factor VIII activity. Based on these results, the dog was diagnosed with haemophilia A. Haemophilia A should be considered in the differential diagnosis of bleeding disorders also in female mixed-breeds dogs.

Anomalous Hall effect in field-effect structures of (Ga,Mn)As.

The anomalous Hall effect in metal-insulator-semiconductor structures having thin (Ga,Mn)As layers as a channel has been studied in a wide range of Mn and hole densities changed by the gate electric field. Strong and unanticipated temperature dependence, including a change of sign, of the anomalous Hall conductance sigma(xy) has been found in samples with the highest Curie temperatures. For more disordered channels, the scaling relation between sigma(xy) and sigma(xx), similar to the one observed previously for thicker samples, is recovered.

Femoral head osteonecrosis can be caused by disruption of the systemic immune response via the toll-like receptor 4 signalling pathway.

OBJECTIVES: Osteonecrosis of the femoral head is observed in patients treated with steroids. However, the pathogenesis of femoral head osteonecrosis remains unclear. We established a rat model with femoral head osteonecrosis by injecting lipopolysaccharide (LPS) and steroid, and assessed the consequences of this on femoral head histology, the systemic immune response and lipid synthesis. METHODS: Male Wistar rats were injected intravenously on days 0 and 1 with 2 mg/kg LPS and intramuscularly with 20 mg/kg methylprednisolone on days 3, 4 and 5. The animals were sacrificed 1, 2, 3 or 4 weeks after the last methylprednisolone injection. Histopathological and biochemical analyses were performed every week. RESULTS: Osteonecrosis of the femoral head was observed in the rats. The plasma triglyceride concentrations had decreased significantly by weeks 2 and 3. The total plasma cholesterol concentrations had increased significantly by week 1 but then decreased significantly by week 4. The plasma concentrations of IL-1beta, IL-2, IL-4, IL-6, IL-10, GM-CSF, IFN-gamma and TNF-alpha had increased significantly by week 1. These cytokines can all be induced by toll-like receptor 4 (TLR4) signalling. CONCLUSIONS: LPS and methylprednisolone induced osteonecrosis of the femoral head in rats and this was associated with a disruption of the innate immune system and lipid synthesis. These findings suggest that the TLR4 signalling pathway plays an important role in the pathogenesis of femoral head osteonecrosis.

Effects of resin hydrophilicity on dentin bond strength.

The purpose of this study was to determine if hydrophobic resins can be coaxed into dentin wet with ethanol instead of water. The test hypothesis was that dentin wet with ethanol would produce higher bond strengths for hydrophobic resins than would dentin wet with water. This study examined the microtensile bond strength of 5 experimental adhesives (50 wt% ethanol/50% comonomers) of various degrees of hydrophilicity to acid-etched dentin that was left moist with water, moist with ethanol, or air-dried. Following composite buildups, hourglass-shaped slabs were prepared from the bonded teeth for microtensile testing. For all 3 types of dentin surfaces, higher bond strengths were achieved with increased resin hydrophilicity. The lowest bond strengths were obtained on dried dentin, while the highest bond strengths were achieved when dentin was bonded moist with ethanol. Wet-bonding with ethanol achieved higher bond strengths with hydrophobic resins than were possible with water-saturated matrices.

Energization of mitochondrial inner membranes caused by L-malate.

It was found that 0.06 mug antimycin A/mg mitochondrial protein, an amount sufficient to inhibit electron transfer between cytochromes b and c1 completely, fully reversed the oxidation of cytochrome a caused by L-malate in anaerobic mitochondria. The effect of L-malate on cytochrome a was insensitive to oligomycin, but all the uncouplers and detergents tested reversed the oxidation of cytochrome a caused by L-malate in anaerobic mitochondria. It was also found that addition of L-malate to anaerobic mitochondria, like addition of ATP, decreased the fluorescence of 1-anilinonaphthalene-8-sulphonate, and that subsequent addition of uncouplers reversed this effect. The effect of L-malate on the fluorescence of the dye was insensitive to oligomycin. The present findings suggest that addition of L-malate may cause energization of the mitochondrial inner membranes and that the oxidation of cytochrome a caused by L-malate in anaerobic mitochondria may result from an L-malate-induced, energy-linked reversal of electron transfer in site II.

Tensile strength of mineralized/demineralized human normal and carious dentin.

The bond strengths of resins to caries-affected dentin are low. This could be due to weakened organic matrix. The purpose of this work was to determine if the ultimate tensile strength (UTS) of excavated carious dentin is weaker than that of normal dentin. Soft caries was excavated from extracted human molars, and the tooth was vertically sectioned into slabs. Each slab was trimmed to an hourglass shape, parallel or perpendicular to the tubule direction. Half of the specimens were mineralized, while the other half were completely demineralized in EDTA. ANOVA on ranks showed that the three-factor interactions (mineralization, caries, tubule direction) were all significant (p < 0.0001), indicating that mineralization and tubule direction gave different UTS results in normal and caries-affected dentin. No significant differences were seen between the UTS of normal and and that of caries-affected demineralized dentin in the parallel or perpendicular group. The matrix of demineralized caries-affected dentin was as strong as that of normal demineralized dentin when tested in the same direction.

Increased urinary levels of adrenomedullin in patients with cystitis.

In this study, we examined urinary levels of adrenomedullin (AM) in 18 healthy volunteers and 18 patients with cystitis. We also compared urinary levels of AM in 11 patients with cystitis before and after antibiotic treatment. Urinary AM concentrations were measured by a radioimmunoassay specific for human AM. Urinary AM levels in patients with cystitis were significantly elevated compared with those of healthy volunteers and correlated positively with the number of urine leukocytes. By antibiotic treatment, urinary AM levels significantly decreased as compared with before the treatment. By RNA blot analysis of AM transcript, we detected significant levels of AM mRNA in canine urinary bladder and ureter. Intravenous administration of lipopolysaccharide elevated the AM mRNA level in the urinary bladder. These data suggest that infection and inflammation stimulate AM production in the urinary tract, which results in increased urinary AM levels in patients with cystitis. Based on these results, it is deduced that AM participates in the pathophysiology of cystitis, and its urinary level could be used as an index of the degree of cystitis.

An allometric model for predicting blood ethanol elimination in mammals.

The relationship of ethanol elimination kinetics in mammals was estimated using the allometric principle. The hypothesis of relationships between parameters obtained from the compartment model with Michaelis-Menten elimination kinetics and body weight can lead to common equations of blood ethanol elimination in mammals. The maximum elimination velocity (g/hr) and the apparent volume of distribution (L) were significantly proportional to the 0.71 and 0.93 powers of body weight (r = 0.994, P < 0.01 and r = 0.998, P < 0.001), respectively. There was no significant relationship between the Michaelis constant and body weight. In the differential equations of the two-compartment model, the kinetics parameters were substituted for the obtained power functions. Good fitting of these equations for the real data showed that ethanol elimination kinetics in mammals can be predicted quantitatively.

Osteopontin-immunoreactive primary sensory neurons in the rat spinal and trigeminal nervous systems.

1200 micrometer(2) and 9% of those in the range 600-1200 micrometer(2) showed the immunoreactivity (ir). DRG neurons <600 micrometer(2)800 micrometer(2) showed the ir and 21% of those in the range 400-800 micrometer(2) were immunoreactive for this protein. TG neurons <400 micrometer(2) were mostly devoid of OPN-ir (2%). Virtually all (99%) Mes5 primary sensory neurons exhibited the ir. Muscle spindles in the soleus and masseter muscles contained OPN-ir spiral axon terminals. In the hard palate and incisor periodontal ligament, unencapsulated corpuscular endings exhibited the ir. The co-expression of OPN with parvalbumin and calcitonin gene-related peptide (CGRP) was also examined in the DRG and TG. In the DRG, virtually all (97%) OPN-ir neurons exhibited parvalbumin-ir. Conversely, 66% of parvalbumin-ir DRG neurons co-expressed OPN-ir. In the TG, 81% of OPN-ir neurons exhibited parvalbumin-ir and 69% of parvalbumin-ir ones showed OPN-ir. Virtually all OPN-ir DRG and TG neurons were devoid of CGRP-ir. The present study indicates that OPN-ir primary sensory neurons in the DRG and Mes5 are spinal and trigeminal proprioceptors. OPN-ir TG neurons appear to include low-threshold mechanoreceptors.

Bonding of self-etch and total-etch adhesives to carious dentin.

Carious dentin is partially demineralized and contains mineral crystals in the tubules. This may permit the deeper etching of intertubular dentin but prevent resin tag formation during bonding. We hypothesize that resin adhesives will produce lower bond strengths to caries-infected and caries-affected dentin compared with normal dentin. We tested this by measuring the microtensile bond strength of a total-etch adhesive and an experimental self-etching adhesive (ABF) to caries-infected, caries-affected, and sound dentin and by correlating those results with ultrastructural observations. The bond strengths of both adhesives to sound dentin were significantly (p < 0.05) higher than those to caries-affected dentin, which, in turn were significantly (p < 0.05) higher than those to caries-infected dentin. For both adhesives, hybrid layers in caries-affected dentin were thicker but more porous than those in sound dentin. The lower bond strengths may be due to the lower tensile strength of caries-affected dentin. Clinically, this may not be a problem, since such lesions are normally surrounded by normal dentin or enamel.

Relationship between cocaine-induced hepatotoxic neurobehavioral & biochemical changes in mice: the antidotal effects of buprenorphine.

Cocaine (COCA)-induced neurobehavioral symptoms, which can be observed simultaneously with exacerbation in biochemical markers, were evaluated in mice, and compared with the changes observed in a representative hepatic failure model induced by thioacetamide (TAA). The effects of pretreatment with buprenorphine (BUP) (0.25, 0.5 or 1 mg/kg i.p.), a mixed opioid agonist-antagonist and an antidote against fatal COCA toxicity, were also examined. At 5 min after the COCA administration (65 mg/kg i.p.), the liver ATP levels were attenuated, and an exacerbation of the CNS-stimulating effects of COCA could be characteristically observed for hepatotoxicity-related neurobehavioral symptoms (changes in alertness, interest, body tension, head movement and walking). At 24 h, the ALT (alanine aminotransferase) activity was elevated, and hepatotoxic attenuation was observed for all of the scores on the neurobehavioral symptoms; this was almost identical to the symptoms observed in the TAA-treated group of mice. Recovery was observed by 72 h for all of the morbid changes. The hepatotoxic biochemical changes and the sum score for all five neurobehavioral symptoms were significantly ameliorated by low doses (0.25 and 0.5 mg/kg) of BUP, both at 5 min and 24 h.

Alteration of odontoblast osteonectin expression following dental cavity preparation.

Cavity preparation can increase the active synthesis and secretion of non-collagenous proteins by odontoblasts, thus resulting in the deposition of tertiary dentine. In this study, the effect of cavity preparation on osteonectin expression was examined in odontoblasts of the rat tooth pulp. A class V cavity was prepared in rat first molars to stimulate odontoblastic secretory activity, and the animals were killed at various intervals. In the normal pulp, osteonectin immunoreactivity was detected in odontoblasts but not other cells. At 1 day after cavity preparation, immunoreactivity had diminished beneath the cavity. At 3 days, strong immunoreactivity could be detected in odontoblasts beneath the cavity. Numerous round cells underlying the odontoblastic layer also demonstrated immunoreactivity. Thereafter, the intensity of osteonectin immunoreactivity in odontoblasts beneath tertiary dentine decreased gradually, and at 30 and 60 days, it was weaker than in normal pulp. These findings suggest that osteonectin is actively synthesized by odontoblasts underlying a cavity in the initial stage of tertiary dentine formation.

cis-Halovinylthioacetamido side chain, a new effective structural element for 7 beta-substitution in cephem and oxacephem antibiotics. I. 7 beta-cis-Chlorovinylthioacetamino-7 alpha-methoxy-1-oxacephems.

The synthesis and in vitro activity of 7 beta-(substituted vinylthioacetamido)-1-oxacephem antibiotics are described. The compounds having a cis-chlorovinylthioacetamido group at C-7 showed high activity against Gram-positive as well as Gram-negative bacteria. The most interesting compound of the series was 51 I because of its high activity and high plasma level in mice.

A novel 1 beta-methylcarbapenem antibiotic, S-4661. Synthesis and structure-activity relationships of 2-(5-substituted pyrrolidin-3-ylthio)-1 beta-methylcarbapenems.

The synthesis and biological activity of (1R,5S,6S)-2-[(3S,5S)-5-substituted pyrrolidin-3-ylthio]-6-[(1R)-1-hydroxyethyl]-1- methylcarbapen-2-em-3-carboxylic acids are described. These compounds exhibit potent antibacterial activity against a wide range of both Gram-positive and Gram-negative bacteria including Pseudomonas aeruginosa. Of these new carbapenems, (1R,5S,6S)-2-[(3S,5S)-5-sulfamoylaminomethyl pyrrolidin-3-ylthio]-6-[(1R)-1-hydroxyethyl]-1-methylcarb apen- 2-em-3-carboxyli c acid (S-4661) showed the most potent and well balanced activity and was selected as a candidate for further evaluation.

Synthesis and modification of a novel 1 beta-methyl carbapenem antibiotic, S-4661.

We describe an efficient method for introducing a sulfamoylamino group into the C-2' position of pyrrolidine using the Mitsunobu reaction. S-4661, its N-methyl analogues and stereoisomers were synthesized using this method and their structure-activity relationships were investigated.

cis-Halovinylthioacetamido side chain, a new effective structural element for 7 beta-substitution in cephem and oxacephem antibiotics. II. 7 beta-cis-Fluorovinylthioacetamino-7 alpha-methoxy-1-oxacephems.

The synthesis and in vitro activity of 1-oxacephem derivatives having a substituted or a non-substituted cis-fluorovinylthioacetamido side chain at C-7 are described. Of these new 1-oxacephem antibiotics, 2355-S (42a) shows good antibacterial activity against Gram-positive and Gram-negative bacteria, and very favorable pharmacokinetic properties.

Study on the mental health of patients with atopic dermatitis in adults.

General Health Questionaire of 60 symptoms proposed by Goldberg was used to study psychiatric condition of 74 patients with severe atopic dermatitis. The patients were composed of 26 males and 48 females. A matched healthy control was obtained from 65 persons of 22 males and 43 females. The patients showed remarkably higher scores than the healthy control in the sum of all morbid ratings and all four scales for somatic symptoms, anxiety and worry, social dysfunction and despondency and depressed mood. The results obtained indicate that atopic dermatitis could be not only disease of dermatology but also accompanied with psychiatric disturbances and even social disease. Then, we propose that intense provision of psychiatric support will be important and necessary to those patients with atopic disease.