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.

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.

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.

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.

Scintigraphic quantification of asynchronous myocardial motion during the left ventricular isovolumic relaxation period: a study in the dog during acute ischemia.

Asynchronous motion of left ventricular myocardium during the period of left ventricular isovolumic relaxation has often been observed in patients with coronary artery disease. Detection and quantitation of this abnormality with noninvasive nuclear tracer methods, however, have not yet been reported. Thus, functional images of regional left ventricular time to minimum counts (or volume), computed from gated blood pool image sequences, were analyzed to detect and quantitate myocardial asynchrony during this interval. The method was tested by comparing regional with global time to minimum counts before and after coronary artery occlusion in the awake dog. After occlusion, minimum counts in the ischemic region occurred later in the cardiac cycle than did global minimum counts (average difference 69 +/- 37 ms, p less than 0.001). Before occlusion, however, minimum counts in the same region occurred at the same moment as global minimum counts (average difference 4 +/- 12 ms, NS). Thus, acute ischemia in dogs produces a pronounced asynchrony in myocardial motion during the earliest moments of diastole. The magnitude of this asynchrony (69 ms) probably corresponds to the length of the global isovolumic relaxation period in these animals after occlusion. This method might be useful in detecting and quantitating isovolumic asynchrony in ischemia and changes in this asynchrony with therapy (verapamil therapy, for example).

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.

Quantitative measurement of electrical instability as a function of myocardial infarct size in the dog.

To investigate the relation between electrical instability and myocardial infarct size, 20 foxhounds were studied in the awake state 3 to 5 days after closed chest coronary occlusion. Programmed right ventricular stimulation was performed with use of an epicardial electrode. After six paced beats at 10 percent greater than control rate, single and then double extrastimuli were introduced, scanning from late diastole to ventricular refractoriness in steps of 10 to 20 ms. Abnormal responses observed after this provocation were repetitive ventricular response, unsustained ventricular tachycardia, sustained ventricular tachycardia and ventricular fibrillation. Scores for electrical instability were determined for each dog, with higher scores assigned for more hazardous tachyarrhythmias (ventricular fibrillation greater than sustained ventricular tachycardia greater than unsustained ventricular tachycardia greater than repetitive ventricular response) and for those provokable later in diastole. An electrical instability index derived from these scores correlated well with infarct size measured with tetrazolium staining (r = 0.94). When scores were given only for the type of abnormal response elicited, excluding the effect of diastolic timing and the number of extrastimuli or vice versa, there was no significant difference in correlation with infarct size (r = 0.85 versus 0.92). Thus the results demonstrate that inducible electrical instability early after infarction is directly related to infarct size. Further, these data demonstrate the usefulness of an electrical instability index derived from the results of programmed right ventricular stimulation in assessing the severity of ischemic damage to the heart.

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.

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.

Do you need an external consultant? A model for decision making.

Consultation is an integral part of the clinical nurse specialist (CNS) role. Some problems, however, are best resolved by a consultant from outside of the organization. This paper presents a decision-making model for use by CNSs in determining the need for an external consultant. The decision-making model involves two general steps. Each step introduces a series of incumbent questions. In the first step, the nature of the problem is assessed, and questions about the philosophical foundation, theoretical framework, and problem substruction are introduced. In the second step, the requirements for solution of the problem are described, precipitating questions about the consultant role requirements, role functions, and introspection and evaluation. Through systematic questioning about the nature of the problem and the solution requirements, the CNS may make an informed decision regarding the recommendation to employ an external consultant. An overall blueprint for the systematic questioning in this decision-making process is presented.

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.

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.