Magnetic ordering through itinerant ferromagnetism in a metal-organic framework

Materials that combine magnetic order with other desirable physical attributes could find transformative applications in spintronics, quantum sensing, low-density magnets and gas separations. Among potential multifunctional magnetic materials, metal-organic frameworks, in particular, bear structures that offer intrinsic porosity, vast chemical and structural programmability, and the tunability of electronic properties. Nevertheless, magnetic order within metal-organic frameworks has generally been limited to low temperatures, owing largely to challenges in creating a strong magnetic exchange. Here we employ the phenomenon of itinerant ferromagnetism to realize magnetic ordering at T_C = 225 K in a mixed-valence chromium(II/III) triazolate compound, which represents the highest ferromagnetic ordering temperature yet observed in a metal-organic framework. The itinerant ferromagnetism proceeds through a double-exchange mechanism, which results in a barrierless charge transport below the Curie temperature and a large negative magnetoresistance of 23% at 5 K. These observations suggest applications for double-exchange-based coordination solids in the emergent fields of magnetoelectrics and spintronics.

Polarized X-ray scattering reveals non-crystalline orientational ordering in organic films

Molecular orientation critically influences the mechanical, chemical, optical and electronic properties of organic materials. So far, molecular-scale ordering in soft matter could be characterized with X-ray or electron microscopy techniques only if the sample exhibited sufficient crystallinity. Here, we show that the resonant scattering of polarized soft X-rays (P-SoXS) by molecular orbitals is not limited by crystallinity and that it can be used to probe molecular orientation down to size scales of 10 nm. We first apply the technique on highly crystalline small-molecule thin films and subsequently use its high sensitivity to probe the impact of liquid-crystalline ordering on charge mobility in polymeric transistors. P-SoXS also reveals scattering anisotropy in amorphous domains of all-polymer organic solar cells where interfacial interactions pattern orientational alignment in the matrix phase, which probably plays an important role in the photophysics. The energy and q-dependence of the scattering anisotropy allows the identification of the composition and the degree of orientational order in the domains.

Soft x-ray scattering facility at the Advanced Light Source with real-time data processing and analysis

We present the development and characterization of a dedicated resonant soft x-ray scattering facility. Capable of operation over a wide energy range, the beamline and endstation are primarily used for scattering from soft matter systems around the carbon K-edge (∼285 eV). We describe the specialized design of the instrument and characteristics of the beamline. Operational characteristics of immediate interest to users such as polarization control, degree of higher harmonic spectral contamination, and detector noise are delineated. Of special interest is the development of a higher harmonic rejection system that improves the spectral purity of the x-ray beam. Special software and a user-friendly interface have been implemented to allow real-time data processing and preliminary data analysis simultaneous with data acquisition.

Study of magnetic anisotropy and magnetization reversal using the quadratic magnetooptical effect in epitaxial Co(x)Mn(y)Ge(z)(111) films

Magnetic anisotropy, magnetization reversal and the magnetooptic Kerr effect in Co(x)Mn(y)Ge(z) have been studied over a range of compositions between 0 and 50 at.% of Ge and between 1 and 3 in the Co to Mn atomic ratio, including the Heusler alloy Co(2)MnGe. A strong quadratic magnetooptic Kerr effect has been observed within a narrow region of composition centered around the Co to Mn atomic ratio of 2, which has been used to probe and quantify the magnetic anisotropy and magnetization reversal of the system. The anisotropy is sixfold with a weak uniaxial component, and it exhibits sensitive dependence on composition, especially on the atomic ratio between Co and Mn. The magnetization reversal process is consistent with the single-domain Stoner-Wohlfarth model.

From theory to practice: identifying authentic opinion leaders to improve care

Diffusion of Innovations and Opinion Leader theories can be translated into practical applications to improve health care delivery and financial performance by applying them to influence referral patterns and decrease variations in care. Health care organizations can rapidly spread "better practices" to their practicing physicians by understanding the social and communication networks that are naturally developed by those practitioners. Physicians view this diffusion process as promoting autonomy, and as a legitimate approach to adoption of information needed in daily practice.

The preterm prediction study: maternal stress is associated with spontaneous preterm birth at less than thirty-five weeks' gestation. National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network

OBJECTIVE

Our purpose was to determine whether various measures of poor psychosocial status in pregnancy are associated with spontaneous preterm birth, fetal growth restriction, or low birth weight.

STUDY DESIGN

Anxiety, stress, self-esteem, mastery, and depression were assessed at 25 to 29 weeks in 2593 gravid women by use of a 28-item Likert scale. Scores for each psychosocial subscale were determined, and an overall psychosocial score was calculated. Scores were divided into quartiles, and the lowest quartile scores were used to define poor psychosocial status. The percent spontaneous preterm birth, low birth weight, and fetal growth restriction in women with low and high psychosocial scores were compared. Logistic regression analyses provided the odds ratios and 95% confidence intervals.

RESULTS

Analyses revealed that stress was significantly associated with spontaneous preterm birth and with low birth weight with odds ratios of 1.16, p = 0.003, and 1.08, p = 0.02, respectively, for each point on the scale. A low score on the combined scale or on any subscale other than stress did not predict spontaneous preterm birth, fetal growth restriction, or low birth weight. After multivariate adjustment was performed for psychosocial status, substance use, and demographic traits, black race was the only variable significantly associated with spontaneous preterm birth, fetal growth restriction, and low birth weight; stress and low education were associated with spontaneous preterm birth and low birth weight.

CONCLUSION

Stress was associated with spontaneous preterm birth and low birth weight even after adjustment for maternal demographic and behavioral characteristics. Black race continues to be a significant predictor of spontaneous preterm birth, fetal growth restriction, and low birth weight even after adjustment for stress, substance use, and other demographic factors.

The nursing management of women experiencing preterm labor: clinical guidelines and why they are needed

Nursing care is a critical component of therapy for women experiencing preterm labor. Diversity exists, however, in the level of comprehensiveness and consistency in guidelines for clinical practice. Nonstandardized care interferes with the ability to achieve consistent, positive patient care outcomes. This article is intended for nurses who seek to organize and standardize their care for women experiencing preterm labor. This article presents a review of the applicable practice and research literature. Clinical guidelines for the nursing management of women experiencing preterm labor are presented in the appendix.

Descriptions of comfort by substance-using and nonusing postpartum women

OBJECTIVE

To compare definitions of comfort held by a group of postpartum substance users with those of a group of nonusers.

SETTING

The postpartum unit of a large university hospital.

PARTICIPANTS

The convenience sample constituted 36 postpartum women; half were substance users and half denied substance use. The nonusing participants were matched to the users according to age, race, type of delivery, and parity.

DESIGN

Qualitative, descriptive.

MAIN OUTCOME MEASURES

Data were collected through semistructured, individual interviews. Patients defined comfort and described the characteristics and patterns of comfort during the postpartum period.

RESULTS

Data were analyzed into three categories of themes. Attributes of comfort were resolution of pain, resolution of fatigue, satiation of hunger, resolution of individual irritants, and relaxation. Interventions for comfort were standard therapy, supportive presence, and caring nursing approach. Modifiers of comfort were individualized comfort patterns, environmental ease, and maternal concern.

CONCLUSIONS

Comfort is more than the absence of pain. A supportive presence and a caring nursing approach were the most helpful interventions.

Injuries to pedal cyclists resulting in death and hospitalisation

AIM

To determine the incidence of injury deaths and hospitalisations associated with pedal cycle use in both traffic and nontraffic environments and in the national population of New Zealand.

METHODS

All cases of pedal cycle injuries resulting in death between 1979-88, and all those resulting in hospitalisation in 1988 were identified from health information services files.

RESULTS

Between 1979 and 1988, 238 cyclists died. Seventy-six percent were male, and 39% of all fatalities occurred to those aged 5-14 years. Collisions with motor vehicles accounted for most fatalities. Head injuries alone, or with other injuries, were associated with death in 60% of cases. In 1988, 1500 cyclists were admitted to hospital for the treatment of their injuries. Fifty-one percent of those hospitalised were aged 5-14, and males accounted for 70% of all admissions. Thirty-four percent involved a collision with a motor vehicle. Intracranial injuries and skull fractures accounted for 46% of hospital admissions, and had the highest scores on the abbreviated injury scale (AIS).

CONCLUSION

This study shows that head injuries are a common cause of death and hospital admission for cyclists. Increases in cycle helmet wearing rates are likely to reduce the frequency and severity of head injury. Other prevention strategies include cycling skills programmes that have been evaluated and shown to be effective, the identification and modification of aspects of cycle design that contribute to injuries, and changes to road design.

A review and integration of knowledge about faculty research productivity

The nursing literature is replete with commentary and opinions about the research and scholarly productivity of nursing faculty. There are also a number of research studies on several aspects of faculty productivity. However, a scholarly critique and integration of research on this topic is lacking. This article reviews the literature on faculty research productivity and synthesizes the findings to present recommendations for promoting nursing faculty research and scholarship.

Calcium signalling in single growth hormone-releasing factor-responsive pituitary cells

The release of pituitary GH appears to be critically dependent on alterations in the free intracellular Ca2+ concentration ([Ca2+]i). However, little is known about the nature of Ca2+ signalling within normal pituitary cells. We, therefore, examined [Ca2+]i patterns in individual cultured pituicytes of adult male rats under basal conditions and in response to GH regulatory agents, using the calcium-sensitive dye fura-2 together with digital imaging microscopy. Perfusion of cultured anterior pituitary cells with GH-releasing factor (GHRF) resulted in a marked increase in [Ca2+]i in specific pituitary cells. These cells did not respond to other hypothalamic secretagogues (GnRH, TRH, or CRF), and there was no evidence of desensitization on repetitive administration of GHRF. Somatotrophs (n = 134) exhibited spontaneous oscillations of [Ca2+]i in the basal state, with considerable heterogeneity of oscillatory patterns among cells. After application of a near-maximal stimulatory dose of GHRF (1 nM), there was a striking 2.2-fold increase in the amplitude of [Ca2+]i oscillations and only a modest increase in their frequency. Forskolin (1 microM) augmented somatotroph [Ca2+]i in patterns similar to those of GHRF. Somatostatin (10 nM) abolished the [Ca2+]i response to GHRF (n = 26); this reflected a marked reduction in the amplitude of [Ca2+]i oscillations and a slight reduction in their frequency. Ca(2+)-free medium or the Ca2+ channel antagonist nimodipine (0.1-1 microM) suppressed the Ca2+ stimulatory effect of GHRF. Conversely, the Ca2+ channel agonist BAY K8644 (1 microM) strikingly augmented the GHRF-induced rise in [Ca2+]i, with a major stimulatory effect on the amplitude of [Ca2+]i oscillations and no observed effect on their frequency. In summary, GHRF and other hypothalamic secretagogues increase [Ca2+]i in pituitary cells in a highly specific manner, consistent with the known specificity of their effects on hormone release. Somatotrophs exhibit spontaneous rhythmic oscillation of [Ca2+]i in the basal state. Known regulators of GH release markedly alter the [Ca2+]i oscillatory pattern in characteristic manners, exerting predominant effects on the amplitude of [Ca2+]i pulses and lesser effects on their frequency. These striking effects of GH regulatory agents on pituitary Ca2+ signalling are consistent with the concept that modulation of [Ca2+]i is a critical mediator of somatotroph function.

The antagonism by BW A868C of PGD2 and BW245C activation of human platelet adenylate cyclase

1. In glycerol-lysed human platelets, prostaglandin D2 (PGD2) and the hydantoin BW245C both activate adenylate cyclase in a biphasic manner. These activations are qualitatively different from those of carbacyclin, iloprost and prostaglandin E2 (PGE2) whose E/[A] curves can be adequately described by rectangular hyperbolae. 2. Prostaglandin E1 (PGE1) had E/[A] curves of slope significantly lower than that expected for a rectangular hyperbolae. 2. Prostaglandin E1 (PGE1) had E/[A] curves of slope significantly lower than that expected for a rectangular hyperbola. 3. The selective PGD2 antagonist BW A868C shifts the first phase of the PGD2 and BW245C E/[A] curves but has no effect on the second phase. 4. Applying a two-receptor model enables a pKB to be derived for BW A868C of 9.11. 5. BW A868C has no effect on carbacyclin, iloprost, prostacyclin, PGE1 and PGE2 at a concentration 1,000 fold that of its KB against PGD2 and BW245C. 6. These results indicate that PGD2 and BW245C are capable of activating adenylate cyclase in human platelets through the DP-receptor and by another mechanism as yet uncharacterized.

The role of the nurse in labor and delivery as perceived by nurses and patients

A study was conducted to examine the role of the labor and delivery room nurse as perceived by expectant mothers trained in the Lamaze method of preparation for childbirth (L/RC), expectant mothers not trained in the Lamaze method (RC), and labor and delivery room nurses. All expectant mothers received baseline prenatal education by attending Red Cross Preparation for Parenthood. Perceptions were measured through a Q-sort of 50 items constructed for this study. Each item described a nursing behavior in labor and delivery. Differences between Q-sorts of expectant mothers and labor and delivery room nurses were insignificant. The collected data showed that labor and delivery room nurses were meeting the expectations of expectant mothers, both trained and not trained in the Lamaze method. Perceptions of the nurse's role in labor and delivery differed slightly so that individualization of care is important.

MORPHOLOGICAL OBSERVATIONS AND MICROSPECTROPHOTOMETRIC DATA FROM PHOTORECEPTORS IN THE RETINA OF THE SEA RAVEN, HEMITRIPTERUS AMERICANUS

A histological survey of the retinas of some fishes has revealed an unusual cone formation. We repeatedly find these unusual triple cones in 10% of the retinas reviewed. To obtain further information about these photoreceptors, the sea raven, whose retina is known to contain them, was chosen for further study. Microspectrophotometric measurements were made to determine the peak absorbance of the visual pigment contained in the three individual outer segments. We report here the results of measurements made on triple cones found in the retina of the sea raven, Hemitripterus americanus.

Blue-sensitive cones in the primate retina: microspectrophotometry of the visual pigment

Direct absorbance and bleaching absorbance-difference spectra were obtained using a photon-counting microspectrophotometer from the outer segments of ten blue-sensitive cones of macaque monkeys. The peak wavelength (lambda max) of the direct measurements was 426 +/- 3.4 nm, whereas the lambda max of the bleaching difference was 434 +/- 6.6 nm. We consider these values to be upper and lower bounds since both measurements may be shifted in opposite directions by wavelength-dependent effects. Therefore, the true peak sensitivity must be close to 430 nm.

Intraretinal distribution of cone pigments in certain teleost fishes

Microspectrophotometric investigations of visual pigments in the teleost family Cichlidae determined that morphological "twin cones" need not be "pigment twins" as well. In each species there were two pigments that could be found in these cells; a "longwave" and a "shortwave" type whose precise spectral location varies for each species, making the terms red and green inadequate to describe them. Studies of the receptor mosaic with the nitro-blue tetrazolium chloride reduction technique permitted the sampling of larger receptor populations and confirmed that twin cones in several cichlid species could be either longwave-longwave, longwave-shortwave, or shortwave-shortwave pairs, and that the relative proportions of these twin cone types vary in different parts of the retinas. Nonuniform distribution of pigment types was also evident in the eyes of several other species from a variety of piscine taxa.

Triple cones found in retinas of 3 fish species

Triple cones were found in the retinas of 3 species of fishes indigenous to the Woods Hole area. The function of these triple cones can not be deduced from the behavior patterns of these fishes.

Sectioning of Epon blocks in the 20 m to 60 micromicron range for histological studies

Thick sections of tissue, (20 micron--60 micron), are useful in studying the relationship between individual large cells and cell layers in organized neural structures. The ability of the Nomarski Differential Interference-Contrast Microscope to bring a single thin layer into sharp focus makes the examination of such sections feasible. Although celloidin is the classical embedding medium for large, thick sections of neural tissue, the time necessary for this preparation is most inconvenient. Epon is an excellent embedding medium; however, it is extremely hard and brittle. By heating the Epon block face, thick sections can be cut. To avoid the cumbersome, often detrimental use of heat, a modification of this technique was found. Epon blocks, trimmed to a 1 millimeter square face, may be sectioned at room temperature on the sliding microtome at 20 micron to 60 micron with ease. The simple method of preparing such sections is described.

Long term fixation for histological studies

It was found that a glutaraldehyde-formalin-phosphate buffered fixative could preserve retinal tissue for light microscopy, even if the tissue remained in the fixative for a month. Retinal tissue that previously was difficult and expensive to procure could now be obtained.

Ellipsosomes: organelles containing a cytochrome-like pigment in the retinal cones of certain fishes

Ellipsosomes are dense spherical bodies containing a very large concentration of a heme pigment spectroscopically resembling pure cytochrome c. They are located at the outer ends of the inner segments of the cones of certain fishes. Although, superficially, they resemble the similarly located oil droplets in the cones of birds and reptiles, their ultrastructure and staining properties resemble those of the neighboring mitochondria. However, like the oil droplets, they may serve as intracellular color filters.