Interface magnetism in epitaxial BiFeO3-La0.7Sr0.3MnO3 heterostructures integrated on Si(100).

We report on the heteroepitaxial growth of ferroelectric (FE)-antiferromagnetic (AFM) BiFeO3 (BFO) on ferromagnetic La0.7Sr0.3MnO3 (LSMO), integrated on Si(100) using pulsed laser deposition via the domain matching epitaxy paradigm. The BFO/LSMO films were epitaxially grown on Si(100) by introducing epitaxial layers of SrTiO3/MgO/TiN. X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, X-ray photo absorption spectroscopy, and atomic force microscopy were employed to fully characterize the samples. Furthermore, we have investigated the magnetic behavior of this five layer heterostructure, in which a d(5) system (Fe(3+)) manifested in FE-AFM BFO is epitaxially conjoined at the interface to a multivalent transition metal ion such as Mn(3+)/Mn(4+) in LSMO. The temperature- and magnetic field-dependent magnetization measurements reveal an unexpected enhancement in magnetic moment and improved magnetic hysteresis squareness originating from the BFO/LSMO interface. We observe a stronger temperature dependence of HEB when the polarity of field cooling is negative as compared to positive field cooling. We believe such an enhancement in magnetic moment and magnetic coupling is likely directly related to an electronic orbital reconstruction at the interface and complex interplay between orbital and spin degrees of freedom, similar to what has previously been reported in the literature. Future work will involve the linearly polarized X-ray absorption measurements to prove this hypothesis. This work represents a starting step toward the realization of magneto-electronic devices integrated with Si(100).

Defects in room-temperature ferromagnetic Cu-doped ZnO films probed by x-ray absorption spectroscopy.

We report a comprehensive study of the defects in room-temperature ferromagnetic (RTFM) Cu-doped ZnO thin films using x-ray absorption spectroscopy. The films are doped with 2 at.% Cu, and are prepared by reactive magnetron sputtering (RMS) and pulsed laser deposition (PLD), respectively. The results reveal unambiguously that atomic point defects exist in these RTFM thin films. The valence states of the Cu ions in both films are 2(+). In the film prepared by PLD, the oxygen vacancies (V(O)) form around both Zn ions and Cu ions in the hexagonal wurtzite structure. Upon annealing of the film in O(2), the V(O) population reduces and so does the RTFM. In the film prepared by RMS, the V(O)s around Cu ions are not detected, and the V(O) population around Zn ions is also smaller than in the PLD-prepared film. However, zinc vacancies (V(Zn)) are evidenced. Given the low doping level of spin-carrying Cu ions, these results provide strong support for defect-mediated ferromagnetism in Cu-doped ZnO thin films.

New methodology for viability testing in environmental samples.

Environmental samples can be complex and are comprised of microorganisms and a matrix of decaying organic matter as well as an inorganic phase such as sand or precipitated material (waste water, sludge, soils, etc.). Nucleic acid dyes have recently been developed to address the growing need for environmental analyses (cell staining, counting, viability testing and specific organism identification). However, certain dyes may not be ideally suited for testing of environmental samples, because they readily adhere to the substrate material as well as their target molecule, resulting in increased non-specific binding and background fluorescence. The aim of this study was to address the limitations of the widely used and commercially available Live/Dead BacLight Bacterial Viability kit (Molecular Probes, Eugene, OR). A new combination of nucleic acid dyes, i.e. SYTO13 and SYTOX Orange (Molecular Probes, Eugene, OR), was proposed as an alternative. The dyes were carefully chosen for their spectral separation and increase of fluorescence quantum yield. A protocol for this combination was first designed and optimized and the two staining assays were compared against suspensions of live and dead E. coli, mixed in different proportions and it was shown that both protocols performed equally on pure cultures. However, when testing activated sludge samples, the commercial kit showed greater background fluorescence and non-specific binding than the alternate combination. Therefore, the proposed dye combination and its corresponding protocol are deemed more suitable for use on complex environmental samples than the Live/Dead BacLight Bacterial Viability kit.

Adult intussusception.

Intussusception occurs when one segment of bowel telescopes into an adjacent segment, resulting in obstruction and possible ischemic injury. The disorder is rare in adults. Most cases of adult intussusception have a demonstrable lead point. Benign and malignant tumors are the cause of intussusception in nearly two-thirds of adult cases. The diagnosis is often elusive because of the vague, chronic nature of the clinical presentation. Symptoms are usually suggestive of intermittent, partial intestinal obstruction. Barium studies or computed tomographic scans can be helpful in making the diagnosis. Surgery is required because of the high incidence of underlying pathology.

Segmenting ultrasound images of the prostate using neural networks.

This paper describes a method for segmenting transrectal ultrasound images of the prostate using feedforward neural networks. Segmenting two-dimensional images of the prostate into prostate and nonprostate regions is required when forming a three-dimensional image of the prostate from a set of parallel two-dimensional images. Three neural network architectures are presented as examples and discussed. Each of these networks was trained using a small portion of a training image segmented by an expert sonographer. The results of applying the trained networks to the entire training image and to adjacent images in the two-dimensional image set are presented and discussed. The final network architecture was also trained with additional data from two other images in the set. The results of applying this retrained network to each of the images in the set are presented and discussed.

Testicular torsion: a surgical emergency.

Testicular torsion is caused by twisting of the spermatic cord, which results in compromised testicular blood flow. The degree of ischemic injury is determined by the severity of arterial compression and the interval between the onset of symptoms and surgical intervention. Torsion usually occurs at puberty, and an anatomic defect known as "bell-clapper" deformity is usually present. Typical symptoms include acute scrotal pain with associated nausea and vomiting. Up to one-half of patients report previous similar episodes. On examination, the testis is high-riding, tender, swollen and firm. Testicular scan or Doppler ultrasound examination can be helpful in distinguishing torsion from acute epididymitis. Prompt surgical treatment is indicated to reduce the torsion, and bilateral orchiopexy is performed to prevent recurrence. Exocrine function, as determined by semen analysis, is often abnormal after unilateral torsion.

Urethral varices as an unusual cause of third-trimester bleeding. A case report.

A 21-year-old woman, gravida 3, para 2, presented in the third trimester of pregnancy with complaints of painless vaginal bleeding after urination. After ruling out placental and uterine sources, the diagnosis of bleeding urethral varices was made with cystoscopy. Once the source of the antepartum hemorrhage had been determined, conservative outpatient management became possible.

Comparative study of the genotoxic properties of Eastern and Western U.S. shale oils, crude petroleum, and coal-derived oil.

A multiple bioassay approach was used to characterize and compare the genotoxicities of an Eastern U.S. (Kentucky) shale oil with the genotoxicities of Western U.S. shale oil, petroleum crude oil, and a coal-derived fuel oil. While the coal-derived oil was mutagenic in the Salmonella/microsome mutagenicity (Ames) assay, the shale oils had negligible to weak mutagenicity, and petroleum crude oil was not mutagenic. All the samples were also tested in the following mammalian test systems: an in vitro sister-chromatid exchange (SCE) assay in human lymphocytes and in vivo tests for induction of sperm abnormalities, micronuclei, and SCE in bone marrow of mice. Slight but statistically significant increases (P less than 0.001) in SCE in human lymphocytes were induced by all samples except petroleum crude oil. Neither sample induced a significant number of mutational events in either of the in vivo systems. In these preliminary studies no major differences in the genotoxicities of Eastern and Western shale oils were observed. The results were consistent with the following order of mutagenic potency: coal oil greater than Eastern and Western shale oil greater than petroleum crude oil.

A comparison of skin temperature and EMG training for primary dysmenorrhea.

Eleven female volunteers completed a 6-month treatment program consisting of a 2-month baseline phase, 2 months of biofeedback training (X number of sessions = 12.9), and 2 months of follow-up data collection. Subjects were assigned to one of two treatment groups: skin temperature training or EMG training of the frontalis muscle. Self-report data were gathered by means of the Symptom Severity Scale. Results, which were analyzed according to a 2 X 3 (treatment X phase) split-plot factorial design, indicate a highly significant overall treatment effect (F = 19.32 p less than .001). There was no significant difference between treatments (F = .47) and no significant interaction effect (F = 1.74).