Understanding Complex Tribofilms by Means of H3BO3-B2O3 Model Glasses.

The discovery of the spontaneous reaction of boric oxides with moisture in the air to form lubricious H3BO3 films has led to great interest in the tribology of boron compounds in general. Despite this, a study of the growth kinetics of H3BO3 on a B2O3 substrate under controlled relative humidity (RH) has not yet been reported in the literature. Here, we describe the tribological properties of H3BO3-B2O3 glass systems after aging under controlled RH over different lengths of time. A series of tribological tests has been performed applying a normal load of 15 N, at both room temperature and 100 °C in YUBASE 4 oil. In addition, the cause of H3BO3 film failure under high-pressure and high-temperature conditions has been studied to find out whether the temperature, the tribostress, or both influence the removal of the lubricious film from the contact points. The following techniques were exploited: confocal Raman spectroscopy to characterize the structure and chemical nature of the glass systems, environmental scanning electron microscopy to examine the morphology of the H3BO3 films developed, atomic force microscopy to monitor changes in roughness as a consequence of the air exposure, focused-ion-beam scanning electron microscopy to measure the average thickness of the H3BO3 films grown over various times on B2O3 glass substrates and to reveal the morphology of the sample in the vertical section, tribological tests to shed light on the system's lubricating properties, and finally small-area X-ray photoelectron spectroscopy to investigate the composition of the transfer film formed on the steel ball while tribotesting.

Spin-Orbit Coupling Controlled J=3/2 Electronic Ground State in 5d

Entanglement of spin and orbital degrees of freedom drives the formation of novel quantum and topological physical states. Here we report resonant inelastic x-ray scattering measurements of the transition metal oxides Ca_{3}LiOsO_{6} and Ba_{2}YOsO_{6}, which reveals a dramatic spitting of the t_{2g} manifold. We invoke an intermediate coupling approach that incorporates both spin-orbit coupling and electron-electron interactions on an even footing and reveal that the ground state of 5d^{3}-based compounds, which has remained elusive in previously applied models, is a novel spin-orbit entangled J=3/2 electronic ground state. This work reveals the hidden diversity of spin-orbit controlled ground states in 5d systems and introduces a new arena in the search for spin-orbit controlled phases of matter.

Quantitative STEM Imaging of Order-Disorder Phenomena in Double Perovskite Thin Films.

Using aberration-corrected high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM), we investigate ordering phenomena in epitaxial thin films of the double perovskite Sr_{2}CrReO_{6}. Experimental and simulated imaging and diffraction are used to identify antiphase domains in the films. Image simulation provides insight into the effects of atomic-scale ordering along the beam direction on HAADF-STEM intensity. We show that probe channeling results in ±20% variation in intensity for a given composition, allowing 3D ordering information to be probed using quantitative STEM.

Epitaxial growth of iridate pyrochlore Nd2Ir2O7 films.

Epitaxial films of the pyrochlore Nd2Ir2O7 have been grown on (111)-oriented yttria-stabilized zirconia (YSZ) substrates by off-axis sputtering followed by post-growth annealing. X-ray diffraction (XRD) results demonstrate phase-pure epitaxial growth of the pyrochlore films on YSZ. Scanning transmission electron microscopy (STEM) investigation of an Nd2Ir2O7 film with a short post-annealing provides insight into the mechanism for crystallization of Nd2Ir2O7 during the post-annealing process. STEM images reveal clear pyrochlore ordering of Nd and Ir in the films. The epitaxial relationship between the YSZ and Nd2Ir2O7 is observed clearly while some interfacial regions show a thin region with polycrystalline Ir nanocrystals.

Raman studies of A2MWO6 tungstate double perovskites.

The Raman spectra of seven A(2)MWO(6) tungstate double perovskites are analysed. Ba(2)MgWO(6) is a cubic double perovskite with Fm3[combining macron]m symmetry and its Raman spectrum contain three modes that can be assigned in a straightforward manner. A fourth mode, the asymmetric stretch of the [WO(6)](6-) octahedron, is too weak to be observed. The symmetry of Ba(2)CaWO(6) is lowered to tetragonal I4/m due to octahedral tilting, but the distortion is sufficiently subtle that the extra bands predicted to appear in the Raman spectrum are not observed. The remaining five compounds have additional octahedral tilts that lower the symmetry to monoclinic P2(1)/n. The further reduction of symmetry leads to the appearance of additional lattice modes involving translations of the A-site cations and librations of the octahedra. Comparing the Raman spectra of fourteen different A(2)MWO(6) tungstate double perovskites shows that the frequency of the symmetric stretch (ν(1)) of the [WO(6)](6-) octahedron is relatively low for cubic perovskites with tolerance factors greater than one due to underbonding of the tungsten and/or M cation. The frequency of this mode increases rapidly as the tolerance factor drops below one, before decreasing gradually as the octahedral tilting gets larger. The frequency of the oxygen bending mode (ν(5)) is shown to be dependent on the mass of the A-site cation due to coupling of the internal bending mode with external A-site cation translation modes.

Probing the spin pumping mechanism: exchange coupling with exponential decay in Y3Fe5O12/barrier/Pt heterostructures.

It is widely believed that the mechanism for spin pumping in ferromagnet-nonmagnet bilayers is the exchange interaction between the ferromagnet and nonmagnetic material. We observe 1000-fold exponential decay of spin pumping from thin Y3Fe5O12 films to Pt across insulating barriers, from which exponential decay lengths of 0.16, 0.19, and 0.23 nm are extracted for oxide barriers having band gaps of 4.91, 3.40, and 2.36 eV, respectively. This archetypal signature of quantum tunneling through a barrier underscores the importance of exchange coupling for spin pumping and reveals its dependence on the characteristics of the barrier material.

Ultrasound-detected thyroid nodule prevalence and radiation dose from fallout.

Settlements near the Semipalatinsk Test Site (SNTS) in northeastern Kazakhstan were exposed to radioactive fallout during 1949-1962. Thyroid disease prevalence among 2994 residents of eight villages was ascertained by ultrasound screening. Malignancy was determined by cytopathology. Individual thyroid doses from external and internal radiation sources were reconstructed from fallout deposition patterns, residential histories and diet, including childhood milk consumption. Point estimates of individual external and internal dose averaged 0.04 Gy (range 0-0.65) and 0.31 Gy (0-9.6), respectively, with a Pearson correlation coefficient of 0.46. Ultrasound-detected thyroid nodule prevalence was 18% and 39% among males and females, respectively. It was significantly and independently associated with both external and internal dose, the main study finding. The estimated relative biological effectiveness of internal compared to external radiation dose was 0.33, with 95% confidence bounds of 0.09-3.11. Prevalence of papillary cancer was 0.9% and was not significantly associated with radiation dose. In terms of excess relative risk per unit dose, our dose-response findings for nodule prevalence are comparable to those from populations exposed to medical X rays and to acute radiation from the Hiroshima and Nagasaki atomic bombings.

Measures of intermittency in driven supersonic flows.

Scaling exponents for structure functions of the velocity, density, and entropy are computed for driven supersonic flows for rms Mach numbers of order unity, with numerical simulations using the piecewise parabolic method algorithm on grids of up to 512(3) points. The driving is made up of either one or three orthogonal shear waves. In all cases studied, the compressible component of the velocity in the statistically steady regime is weaker than its solenoidal counterpart by roughly a factor of 6. Exponents for the longitudinal component of the velocity are comparable to what is found in the incompressible case and appear insensitive to the presence of numerous shocks. Scaling exponents of the transverse components of the velocity are comparable to those for the longitudinal component. Density and entropy structure functions display strong departures from linear scaling. Finally, the scaling of structure functions of the energy transfer is also given and compared with the Kolmogorov refined similarity hypothesis.

Prediction of the crystal structures of perovskites using the software program SPuDS.

The software program SPuDS has been developed to predict the crystal structures of perovskites, including those distorted by tilting of the octahedra. The user inputs the composition and SPuDS calculates the optimal structure in ten different Glazer tilt systems. This is performed by distorting the structure to minimize the global instability index, while maintaining rigid octahedra. The location of the A-site cation is chosen so as to maximize the symmetry of its coordination environment. In its current form SPuDS can handle up to four different A-site cations in the same structure, but only one octahedral ion. Structures predicted by SPuDS are compared with a number of previously determined structures to illustrate the accuracy of this approach. SPuDS is also used to examine the prospects for synthesizing new compounds in tilt systems with multiple A-site coordination geometries (a(+)a(+)a(+), a(0)b(+)b(+), a(0)b(-)c(+)).

Endometriosis: radiologic-pathologic correlation.

Endometriosis is an important gynecologic disorder primarily affecting women during their reproductive years. Pathologically, it is the result of functional endometrium located outside the uterus. It may vary from microscopic endometriotic implants to large cysts (endometriomas). The physical manifestations are protean, with some patients being asymptomatic and others having disabling pelvic pain, infertility, or adnexal masses. Symptoms do not necessarily correlate with the severity of the disease. Ultrasonographic (US) features are variable and can mimic those of other benign and malignant ovarian lesions. Low-level internal echoes and echogenic wall foci are more specific US features for endometriomas. Magnetic resonance imaging improves diagnostic accuracy, with endometriotic cysts typically appearing with high signal intensity on T1-weighted images and demonstrating "shading" on T2-weighted images. The ovaries are the most common sites affected, but endometriosis can also involve the gastrointestinal tract, urinary tract, chest, and soft tissues. Small implants and adhesions are not well evaluated radiologically; therefore, laparoscopy remains the standard of reference for diagnosis and staging. Both medical and surgical treatment options are available depending on the patient's specific case.

MRI of the female pelvis.

MRI is a proven modality to evaluate the female pelvis. Excellent soft tissue contrast, sensitivity for the detection of fluid, and the multiplanar imaging capabilities of MR allow noninvasive demonstration of normal anatomy and pathological processes. Most female pelvic MRI studies are performed to answer specific questions and must, therefore, follow carefully developed protocols, which are discussed in this article. The principal MRI techniques and strategies outlined in this work include: (1) the evaluation of reproductive dysfunction, anatomic variants; (2) specific obstetrical applications; (3) oncologic evaluation and tumor staging; (4) problem solving (i.e., the characterization of abnormalities detected by ultrasound); and (5) the evaluation of urethral disease.

Sonohysterography: technique, endometrial findings, and clinical applications.

Transvaginal ultrasound-guided saline infusion sonohysterography (SHG) is a relatively new technique for evaluation of the uterine cavity. As new studies declare the clinical usefulness of this technique, SHG may quickly become part of the routine ultrasound evaluation of the female pelvis. In this article, the SHG procedure is described and normal findings are discussed. Common endometrial pathological findings such as atrophy, polyps, fibroids, hyperplasia, and carcinoma are reviewed. The newly touted roles of SHG for screening patients on long-term tamoxifen therapy and for evaluating patients with infertility are introduced. Finally, we present a practical ultrasound-based flow chart for the workup of menopausal and perimenopausal patients with abnormal uterine bleeding.

A multisite phase III study of the safety and efficacy of a new manganese chloride-based gastrointestinal contrast agent for MRI of the abdomen and pelvis.

The purpose of this study was to evaluate the safety and efficacy of a manganese chloride-based oral magnetic resonance (MR) contrast agent during a Phase III multisite clinical trial. Two hundred seventeen patients were enrolled who were already scheduled for MRI of the abdomen and/or pelvis. In this group of patients, it was postulated that the use of an oral agent would better allow discrimination of pathology from bowel. Patients with known gastrointestinal pathology including peptic ulcer disease, inflammatory bowel disease, obstruction, or perforation were excluded to minimize confounding variables that could affect the safety assessment. Of these 217 patients, 18 received up to 900 mL of placebo, and 199 patients were given up to 900 mL of a manganese chloride-based oral contrast agent, LumenHance (Bracco Diagnostics, Inc.). Safety was determined by comparing pre- and post-dose physical examinations, vital signs, and laboratory examinations and by documenting adverse events. Efficacy was assessed by unblinded site investigators and two blinded reviewers who compared pre- and post-dose T1- and T2-weighted MRI scans of the abdomen and/or pelvis. In 111 (57%) of the 195 cases evaluated for efficacy by site investigators (unblinded readers), MRI after LumenHance provided additional diagnostic information. Increased information was found by two blinded readers in 52% and 51% of patients, respectively. In 44/195 cases (23%) unblinded readers felt the additional information would have changed patient diagnosis and in 50 patients (26%), it would have changed management and/or therapy. Potential changes in patient diagnosis or management/therapy were seen by the two blinded readers in 8-20% of patients. No clinically significant post-dose laboratory changes were seen. Forty-eight patients (24%) receiving LumenHance and four patients (22%) receiving placebo experienced one or more adverse events. Gastrointestinal tract side effects were most common, seen in 29 (15%) of LumenHance patients and in 3 (17%) of the placebo patients. LumenHance is a safe and efficacious oral gastrointestinal contrast agent for MRI of the abdomen and pelvis.

Suicide and violence prevention: parent education in the emergency department.

OBJECTIVE: To determine prospectively whether parental receipt of injury prevention education is associated with new action limiting access to lethal means and if so, what action was taken for which means. METHOD: Prospective follow-up of 103 adults whose children made an emergency department visit for mental health assessment or treatment. Record review assessed whether hospital staff provided injury prevention education. Logistic regression was used to determine the likelihood of new caretaker action limiting access to the following potentially lethal means: firearms, alcohol, prescription medications, and over-the-counter medications. RESULTS: Significant associations were found between exposure to injury prevention education and action to limit access (adjusted odds ratio = 3.6, 95% confidence interval = 1.1-12.1, p = .04). Five of 8 adults whose households contained firearms took new action to limit access after injury prevention education, whereas none of the 7 firearm-owning families who did not receive injury prevention education took new action to limit firearm access. Similar patterns were seen for other means. Adults more often chose to lock up rather than dispose of lethal means. CONCLUSIONS: Injury prevention education should be provided to parents during child/adolescent emergency department mental health-related visits. Potential for violence prevention is real because parents do take new action to limit access to lethal means when means restriction education is provided.

MR imaging of the adrenal glands and kidneys.

MR imaging of the adrenal glands and kidneys can completely and accurately assess these organs for a variety of abnormalities. One of the major strengths of MR imaging of the adrenal glands is the ability of chemical shift imaging to determine the presence of intracellular lipid, thus enabling distinction of benign adrenal adenomas from other adrenal masses. The multiplanar imaging capability of MR can assist in determining the origin of large retroperitoneal masses. MR imaging of the kidneys has many applications, including staging of renal cell carcinomas and evaluating the renal vasculature. Gadolinium is a safe and non-nephrotoxic contrast agent that can be used to evaluate the kidneys in patients with renal compromise. The many advances and current research being performed in the rapidly expanding field of abdominal MR make performing these cases both exciting and challenging.

Magnetic resonance imaging of the female pelvis.

Evaluation of pelvic pathology is an important part of most radiology practices. Magnetic resonance imaging (MRI) has proven itself to be a useful and cost-effective method in evaluating many of these diseases. This article reviews appropriate MR imaging techniques and findings of common gynecologic disorders. Uterine pathology is categorized into congenital anomalies, benign lesions (leiomyomas, adenomyosis, endometrial polyps, and nabothian cysts), and malignancies (endometrial and cervical carcinoma). Adnexal pathology reviewed includes endometriosis, polycystic ovaries, teratomas, and benign and malignant ovarian epithelial tumors.

Child and adolescent suicide attempts: an opportunity for emergency departments to provide injury prevention education.

The study objectives were to ascertain whether caretakers of suicidal children and adolescents received emergency department (ED) injury prevention education and to determine if injury prevention education and the medical outcome after a drug overdose are associated with caretakers restricting access to means of suicide. Participants were adult caretakers of children and adolescents who deliberately ingested a drug and received ED evaluation. Information was obtained by poison center chart review and phone interview. Fourteen percent of caretaker reported receiving injury prevention education concerning restriction of access to potential means of suicide at home. ED injury prevention education is significantly associated with caretakers restricting access to suicidal means, even when controlling for medical outcome from the attempt. Because parents are less likely to restrict access to means of suicide without education, injury prevention education about restricting access to means of suicide should be given in the ED.

Postmortem fetal MR imaging: comparison with findings at autopsy.

OBJECTIVE: The purpose of this study was to prospectively compare findings from postmortem fetal MR imaging with findings at autopsy. SUBJECTS AND METHODS: Twenty-six fetuses were imaged on a 1.5-T MR scanner using two-dimensional and high-resolution three-dimensional fast spin-echo techniques immediately before autopsy. The MR images were reviewed independently by three radiologists who evaluated then for major and minor malformations. These findings were then compared with those at autopsy. RESULTS: The 26 subjects had 47 major and 11 minor malformations. All three radiologists correctly identified 37 of the major malformations on the MR images (detection rate, 79%), and at least one of the three reviewers correctly identified 43 of the abnormalities (detection rate, 91%). Only one of the 11 minor anomalies was identified by any reviewer. Reviewers made six false-positive diagnoses. In two cases, both with major CNS malformations, MR imaging was superior to autopsy in defining in situ relationships. CONCLUSION: Although autopsy remains the study of choice for evaluating causes of fetal death, MR imaging is an excellent alternative when autopsy is refused. Additionally, MR imaging may be a valuable adjunct to autopsy for fetuses with CNS anomalies.