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PubMed2001

Light reflected from colored mulches affects aroma and phenol content of sweet basil (Ocimum basilicum L.) leaves.

Basil (Ocimum basilicum L.) is an herb the leaves of which are used to add a distinct aroma and flavor to food. It was hypothesized that the size and chemical composition of sun-grown basil leaves could be influenced by the color of light reflected from the soil surface and by the action of the reflected light through the natural growth regulatory system within the growing plants. Leaf morphology, aroma compounds, and soluble phenolics were compared in basil that had been grown over six colors of polyethylene row covers. Altering the ratios of blue, red, and far-red light reflected to growing plants influenced both leaf morphology and chemistry. Leaves developing over red surfaces had greater area, moisture percentage (succulence), and fresh weight than those developing over black surfaces. Basil grown over yellow and green surfaces produced significantly higher concentrations of aroma compounds than did basil grown over white and blue covers. Leaves grown over yellow and green mulches also contained significantly higher concentrations of phenolics than those grown over the other colors. Clearly, the wavelengths (color) of light reflected to growing basil plants affected leaf size, aroma, and concentrations of soluble phenolics, some of which are antioxidants.

Color↗

PubMed2005

Specular X-ray reflectivity and small angle neutron scattering for structure determination of ordered mesoporous dielectric films.

Specular X-ray reflectivity (SXR) and small-angle neutron scattering (SANS) are used to characterize the structure of a thin film containing cylindrical mesopores. The 3-D structure of the mesoporous film was determined from SANS measurements taken at multiple rotation angles between the incident beam and the film. The film was found to be composed of a randomly packed core and surface layers within which the hollow cylinders were regularly packed and oriented along the surface. The packing of the cylindrical mesopores was not hexagonal but rather rectangular with a conical angle of 55.7 degrees instead of 60 degrees expected for hexagonal packing. The extent of the planar orientation of the cylindrical mesopores within the surface layers was estimated from the width of the Bragg reflection in the SXR result to be about 25 repeating layers at both interfaces. This was further confirmed from cross-section transmission electron microscopy (TEM) results. The SXR results of this film exhibit an anomalous decrease in reflected intensity after each Bragg reflection. This anomaly in SXR can be modeled in a Parratt formulism using a depth profile composed of two characteristic lengths, the repeating distance among layers and the curvature of the density profile of each layer.

Journal Article↗

PubMed1997

Accuracy and utility of a new reflectance pulse oximeter for fetal monitoring during labor.

OBJECTIVE: To evaluate the accuracy of a new pulse oximeter in estimating the oxyhemoglobin (O2Hb) concentration in fetal arterial blood (SaO2) with either a high concentration of hemoglobin F (HbF) or a low concentration of O2Hb during labor. PATIENTS AND METHODS: Fetal forehead arterial oxygenation was determined in 44 fetuses by reflectance pulse oximeter (SpO2) during labor and was compared with SaO2 determined immediately after birth. Because HbF has little or no known effect on pulse oximetry, but does affect the laboratory multiwavelength "CO-oximeter" type reading, the SaO2 was corrected by HbF concentration. SpO2 and SaO2 were simultaneously measured in five hypoxic adult volunteers achieved by inhaling 11% oxygen. RESULTS: A gradual decline in HbF concentration was seen during weeks 37 to 40 of gestation. HbF concentration varied near term, ranging between 53 and 88% of the fetal hemoglobin concentration (mean +/- SD = 74.6 +/- 6.3%). This alteration produced a lower %O2Hb percent by 4% at the most. The corrected SaO2 in cord blood correlated with fetal SpO2 (y = 0.974, x -7.279, r = 0.90). In five adults, SpO2 reflected well SaO2 with a mean +/- SD of bias of -1.1 +/- 2.9%. CONCLUSIONS: SpO2 determined by a new reflectance pulse oximeter at the end of labor correlated with an immediate post-natal cord arterial blood sample before the first breath, with a mean and SD of bias of 8.5 +/- 6.2%. Reflectance pulse oximetry is a useful tool for continuous noninvasive monitoring of the fetal oxygen status during labor.

Adult↗

PubMed2004

Ecology: ultraviolet reflectance by the skin of nestlings.

Birds can perceive the reflectance of ultraviolet light by biological structures. Here we show that the skin of the mouth and body of starling nestlings substantially reflects light in the ultraviolet range and that young in which this reflectance is reduced will gain less mass than controls, despite low background levels of ultraviolet and visible light in the nest. We suggest that this ultraviolet reflectance from starling nestlings and its contrast with surrounding surfaces are important for parental decisions about food allocation.

Animals↗

PubMed2005

In vivo and ex vivo virtual biopsy of the liver with near-infrared, reflectance confocal microscopy.

The assessment of liver architecture is an essential part of the understanding of its physiology and pathology. Current fluorescence confocal microscopy methods face numerous drawbacks, such as cytotoxicity, quenching effect, potential negative ino- and chrono-tropic effects and leaking of fluorescent agents through the sinusoid fenestrations. The recently developed, near-infrared reflectance confocal microscopy allows high-resolution optical sectioning through intact tissues, without employing fluorescent stains, while contrast between structures is provided by the natural refractivity of the tissue. The aim of this study is to assess the utility of near-infrared reflectance confocal microscopy in the evaluation of the hepatic microscopic architecture in vivo and ex vivo. Rat livers were noninvasively examined in vivo and ex vivo with near-infrared reflectance confocal microscopy. Two experimental contrast agents were subsequently used to enhance particular structures. Parenchymal and vascular structures are readily identified, as well as some intracellular details. Differences between in vivo and ex vivo states were also observed. The use of contrast agents also highlights certain morphologic structures. In conclusion, near-infrared reflectance confocal microscopy stands as a useful adjunct technique to the study of hepatic parenchyma offering details equivalent to, if not surpassing traditional light microscopy.

Animals↗

PubMed2003

Reflection signature of seismic and aseismic slip on the northern Cascadia subduction interface.

At the northern Cascadia margin, the Juan de Fuca plate is underthrusting North America at about 45 mm x yr(-1) (ref. 1), resulting in the potential for destructive great earthquakes. The downdip extent of coupling between the two plates is difficult to determine because the most recent such earthquake (thought to have been in 1700) occurred before instrumental recording. Thermal and deformation studies indicate that, off southern Vancouver Island, the interplate interface is presently fully locked for a distance of approximately 60 km downdip from the deformation front. Great thrust earthquakes on this section of the interface (with magnitudes of up to 9) have been estimated to occur at an average interval of about 590 yr (ref. 3). Further downdip there is a transition from fully locked behaviour to aseismic sliding (where high temperatures allow ductile deformation), with the deep aseismic zone exhibiting slow-slip thrust events. Here we show that there is a change in the reflection character on seismic images from a thin sharp reflection where the subduction thrust is inferred to be locked, to a broad reflection band at greater depth where aseismic slip is thought to be occurring. This change in reflection character may provide a new technique to map the landward extent of rupture in great earthquakes and improve the characterization of seismic hazards in subduction zones.

Journal Article↗

PubMed2006

Seismic reflection images of the Moho underlying melt sills at the East Pacific Rise.

The determination of melt distribution in the crust and the nature of the crust-mantle boundary (the 'Moho') is fundamental to the understanding of crustal accretion processes at oceanic spreading centres. Upper-crustal magma chambers have been imaged beneath fast- and intermediate-spreading centres but it has been difficult to image structures beneath these magma sills. Using three-dimensional seismic reflection images, here we report the presence of Moho reflections beneath a crustal magma chamber at the 9 degrees 03' N overlapping spreading centre, East Pacific Rise. Our observations highlight the formation of the Moho at zero-aged crust. Over a distance of less than 7 km along the ridge crest, a rapid increase in two-way travel time of seismic waves between the magma chamber and Moho reflections is observed, which we suggest is due to a melt anomaly in the lower crust. The amplitude versus offset variation of reflections from the magma chamber shows a coincident region of higher melt fraction overlying this anomalous region, supporting the conclusion of additional melt at depth.

Journal Article↗

PubMed2002

Reversibly erasable nanoporous anti-reflection coatings from polyelectrolyte multilayers.

For nearly two centuries, researchers have sought novel methods to increase light transmission in optical systems, as well as to eliminate unwanted reflections and glare. Anti-reflection coatings and surfaces have enabled the increasing performance demands of optical components fabricated from glass-based optical materials. With the current trend of technology moving towards optically transparent polymeric media and coatings, the need for anti-reflection technology and environmentally benign processing methods for polymeric materials independent of shape or size has become quite apparent. We describe an economical, aqueous-based process controlled at the molecular level that simultaneously coats all surfaces of almost any material. Systematically designed nanoporous polymer films are used, which are suitable for optical applications operating at both visible and near-infrared wavelengths. These high-efficiency anti-reflection coatings are created from phase-separated polyelectrolyte multilayer films that undergo a reversible pH-induced swelling transition. Furthermore, such films, easily patterned by an inkjet printing technique, possess potential for pH-responsive biomaterial and membrane applications.

Journal Article↗

PubMed2001

Effect of sildenafil on blood pressure and arterial wave reflection in treated hypertensive men.

As the effects of sildenafil are in part mediated by enhancing the action of nitric oxide and nitrates given acutely markedly reduce early wave reflection, we explored the effects of a single oral dose of sildenafil citrate (50 mg) on blood pressure and arterial wave reflection in treated hypertensive men in a single-blind randomised placebo controlled crossover study. Eight men (aged 57-76 years) with well controlled hypertension and erectile dysfunction and no contraindications to the use of sildenafil, were given either sildenafil 50 mg or placebo orally, with the second drug being given 2 weeks later. Blood pressure and heart rate with an automated digital oscillometric device (Omron) HEM-705 CP) and the augmentation index, a measure of arterial wave reflection in the aorta derived using radial applanation tonometry, were measured before and at 15-min intervals for 2 h thereafter. The extent of individual maximum reductions (mm Hg) from baseline in systolic (24 +/- 10 vs. 6 +/- 8, P < 0.05) and diastolic blood pressure (8 +/- 5 vs. 3 +/- 2, P < 0.05) occurred on the sildenafil study day. On average the brachial blood pressure at 75 min following sildenafil was 17/11 mm less than on the placebo day (P < 0.01). Augmentation index was also reduced significantly at 90 min (P < 0.05) suggesting reduced vascular tone in the arteries. The area under the brachial and aortic blood pressure and augmentation index time curve (by the trapezoidal rule corrected for baseline reading) was significantly lower (P < 0.05) on the sildenafil study day. The study shows that the peripheral vasodilatory effects of sildenafil, possibly related to nitric oxide, are accompanied by a fall in systemic blood pressure and reduced arterial wave reflection.

Aged↗

PubMed2004

Reflectance pulse oximetry from core body in neonates and infants: comparison to arterial blood oxygen saturation and to transmission pulse oximetry.

OBJECTIVE: To compare pulse oximetry oxygen saturation (SpO(2)) measured by a novel reflectance method from core body to arterial oxygen saturation (SaO(2)) in neonates and infants. Transmission pulse oximetry (TPO) was measured for comparison. STUDY DESIGN: We monitored 18 infants by the two pulse oximeters simultaneously. The reflectance pulse oximetry (RPO) (PRO2, ConMed, Utica, NY) was measured on the upper back or chest, while the TPO (N395-Nellcor, Pleasanton, CA) was measured from the finger of the infant on the left hand or feet. Data from the two methods were compared to functional SaO(2) derived from blood sample drawn from arterial line for patient care and measured by a Co-oximeter (Ilex, Instrument Lab. Lexington, MA). The potential advantage of the RPO is demonstrated in a case of a premature infant with hypovolemic shock, where SaO(2) or TPO could not be obtained but oximetry was available from the RPO. RESULTS: We used for analysis 56 RPO and 32 TPO measurements. SpO(2) obtained from the RPO was 88.3+/-9.8%, from the TPO 84.2+/-10.1%, and functional SaO(2) was 88.2+/-11.7%, with correlation coefficient of 0.93 and 0.88, respectively (p<0.0001). The mean difference (bias) and standard deviation of the differences (precision) between the RPO and the TPO compared to functional SaO(2) were -0.09+/-4.5% and 1.26+/-5.9% and the absolute errors were 3.2+/-3.1%, and 4.4+/-4.0%, respectively. The accuracy of both RPO and TPO was diminished when SaO(2) was <85%, but only the RPO remained correlated with the functional SaO(2). CONCLUSIONS: Reflectance pulse oximetry measured from core body of neonates and infants is accurate and reliable and is comparable to the transmission SpO(2) when compared to functional SaO(2). We speculate that the reflectance method might be advantageous in cases of poor peripheral perfusion in neonates and infants.

Blood Gas Monitoring, Transcutaneous↗

PubMed2006

Modeling pigment contributions to spectral reflection of apple fruit.

A simple approach for spectral reconstruction of spectral reflection by whole apple fruit is described. It is shown that an approximation to the reflection spectrum can be obtained by making a simple assumption on the shape of the featureless scattering and using known spectral properties of the following pigment pools: (i) thylakoid-bound chlorophylls and carotenoids, (ii) cuticular/vacuolar phenolics, (iii) extrathylakoid chloroplasts/chromoplasts carotenoids, and (iv) vacuolar anthocyanins. The in vivo spectra of individual pigment pools estimated in bleaching experiments or as a difference between fruit with high and low pigment content are presented. In most cases simulations based on a linear combination of spectra proved to be effective, but fruit with high chlorophyll content necessitated the use of a non-linear model. The models succeeded in simulating reflection spectra of fruit widely differing in pigment content and composition with relative error lower than +/-4% over the visible range. The estimated relative contributions by the pigment pools into total reflection were found to be sensitive indicators of apple fruit ripening and could be useful in evaluating the light screening efficacy by flavonoids and carotenoids under stress conditions.

Fruit↗

PubMed1996

Changing nursing practice through reflection on the Roper, Logan and Tierney model: the enhancement approach to action research.

To the clinical practitioner both nursing models and nursing research may currently be highly valued by practitioners or managers. Yet, by facilitating group reflection on the nursing model identified in the ward philosophy and adopting the enhancement approach to action research, surgical nurses were empowered to effect change and, consequently, to enhance the quality of patient care in their ward. The study was undertaken in two phases over a 15-month period and utilized a multi-method approach. In phase 1 triangulation of the data enabled the practitioners/co-researchers to identify and reflect on patients' psychological needs within the independence/dependence continuum of the Roper et al. (1990) model. Phase 2 involved a collaborative approach to the planning, implementation and evaluation of innovations which resulted from reflection on practice. Nurse-doctor relationships including anaesthetist noncompliance were, though, a controversial issue. Collaborative practice was undermined by the co-researchers' ambivalence concerning feedback from the medical staff. Overall, however, the individual contribution of each co-researcher was recognized and valued. They had both choice and control which enabled them to develop personally and professionally. Group reflection was seen as essential feedback strategy during the change process.

Attitude of Health Personnel↗

PubMed1996

Reflection as infiltration: learning in the experiential domain.

This paper discusses part of an ethnomethodological study of a short, post-registration course in communication in palliative care. The study describes the different perceptions, expectations and reflections of the participants and the facilitators as they engaged together in learning through role-play, simulated interviews with patients and discussion. The emotionally challenging nature of experiential teaching in palliative care appeared to present the facilitators of the course with a number of dilemmas. The facilitators' reflections upon these dilemmas appeared to lead them to develop a series of strategies in an attempt to resolve them. During the study it became clear that some aspects of these strategies were withheld from the participants. These strategies and the reasoning behind them are described together with the participants' response. The study demonstrates how the participants' reflections upon the facilitator-led exercises led them to infiltrate the strategies adopted by the facilitators. The purpose of these strategies and the significance of the participants' unearthing of them are interpreted within the conceptual framework of Schön's "reflective practitioner'. The findings are discussed in relation to current nurse education and the possible implications for curriculum planning and development.

Education, Nursing, Continuing↗

PubMed1998

Evaluating the efficacy of reflective practice within the context of clinical supervision.

This paper explores the efficacy of reflective practice within the context of clinical supervision. It examines some potential limitations that reflective practice has within the context of clinical supervision drawing upon the literature and the early stages of the author's empirical work. It concludes that whilst there is considerable congruence in the use of reflective practice within clinical supervision sessions, there are potential disadvantages in making the assumption that reflective practice should be an integral part of all forms of clinical supervision.

Education, Nursing↗

PubMed1999

Evaluation of reflective learning in a psychodynamic group of nurses caring for terminally ill patients.

The development of a psychodynamic group comprising seven female nurses was studied for 1 year (31 sessions). The group was part of a 1-year postgraduate training in patient-centred nursing. The members of the group all worked on the same unit; none of them left the unit or the group during the study. As the nurse-patient relationship is considered to be crucial for patient-centred nursing, the group sessions focused on the problems which the nurses experienced in their relationships with the patients. The objective of the group-work was to improve the nurses' ability to reflect on these relationships. The purpose of the study was to evaluate the group sessions, concentrating on the characteristics of patients selected for discussions, group process over time, and impact of specific patient characteristics on the group-work. Transcriptions of the tape-recorded group sessions were made for systematic analysis. A category system was developed and validated to rate reflection about the patient, the nurses themselves and the nurse-patient relationship. The results showed that the nurses over-proportionally selected terminally ill patients, as well as patients who were female and within a similar age range as themselves. These results could be due to an identification with these patients, causing increased psychological stress on the nurses. Throughout the year, the nurses' verbal activity and their reflections about their patients increased, whereas their reflections about themselves decreased. The need to withdraw and protect oneself by focusing more on the patient than on oneself might have been a strategy the nurses used to cope with growing stress.

Adult↗

PubMed2001

Healing through self-reflection.

BACKGROUND: Today, women have an enlightened view towards their life cycles, which is evidence of their healing potential. Women need to share their insights about their healing potential gained through self-reflective processes. Their voices must be heard so that we can benefit from their collective wisdom. The process of healing through self-reflection has begun as a group of nurses share their insights. Documenting the perspectives of these nurses provides the opportunity for other women to learn from and apply this knowledge to their lives. METHOD: Through purposive sampling, eight registered nurses, all women, were selected to participate in in-depth, personal, semi-structured interviews. The purposes in this paper are to describe a three-stage (i.e. awareness, critical analysis, and new perspective) reflective-thinking model and discuss the application of this model to women's expressed inner knowledge and wisdom across personal and professional life cycles. RESULTS: Three themes, signifying their ability to heal themselves, were labelled: Spirituality, Be-ing Versus Do-ing, and Eustress Versus Distress. CONCLUSIONS: Essentially, self-reflection results from both personal and professional stimuli and signifies the need for change so that healing can begin. Recommendations are offered for nurse educators and researchers.

Adaptation, Psychological↗

PubMed2001

Reflective practice and clinical supervision: meticulous rituals of the confessional.

BACKGROUND: Reflective practice and clinical supervision are progressively asserting hegemony upon nursing practice with claims of emancipation and empowerment. However, this is being achieved in an environment where there is little critical debate about the assumptions on which these practices are based. AIM: This paper sets out to challenge the basis upon which reflective practice and clinical supervision are promoted within nursing discourse by employing Michel Foucault's (1982) concept of governmentality. Theme. A broad Foucauldian perspective is used to demonstrate how the technologies of reflective practice and clinical supervision have been accommodated within modern forms of government. These technologies are consistent with the flattened hierarchies and increasing dispersal of practitioners in contemporary health care. In this context reflective practice and clinical supervision can be shown to function in two independent but interrelated ways. First as modes of surveillance disciplining the activity of professionals. Second, as "confessional" practices that work to produce particular identities--autonomous and self-regulating.

Ceremonial Behavior↗

PubMed2000

Practice-based learning: views on the development of a reflective learning tool.

CONTEXT: This study reports the first part of a funded project to develop a tool to improve and record learning, known as a Progress File. A Progress File typically contains an element of reflection and a means of recording achievement. AIM: The aim of the study was to collect and understand the attitudes and experiences of students and tutors with regard to reflection, and to determine their views on the development and implementation of a Progress File for one member of the dental team, the dental therapist. METHOD: A consultation exercise was undertaken in four institutions which train dental therapists. A total of 76 students and tutors were interviewed individually or in groups. Examples of reflective tools were used to prompt discussion and feedback. Emergent themes were derived from content analysis. RESULTS: Participants identified many uses for the Progress File within and beyond their courses. They also expressed concerns regarding the effectiveness and feasibility of Progress File learning within present educational environments. DISCUSSION AND CONCLUSION: Successful integration of the Progress File into courses of medical and dental education may depend upon institutional culture change and a move towards a system which facilitates and rewards reflection on learning. The results will inform development of the File.

Attitude of Health Personnel↗