bluuebunny/crossref_metadata_2025 huggingface dataset:
The willingness to eat
Authors: Wikby Kerstin , Fägerskiöld Astrid
Published: May 2004

The aim of this study was to identify and describe factors of importance with regard to appetite among elderly people. A qualitative approach was used and the method was grounded theory. Fifteen elderly people were interviewed using a method with two overall questions. The results show that the willingness to eat plays a central role in appetite among elderly people. The appetite is a state on a sliding scale, from good to poor appetite. Factors affecting the appetite include six categories: mood, personal values, wholesomeness, food, eating environment and meal fellowship. When planning and realizing nursing actions concerning eating, the willingness to eat has to be observed. The desire within every individual has to be given consideration, including all factors as well as how they affect each other. The willingness to eat contains internal factors dependent on mood and personal values, as well as external factors dependent on wholesomeness, food, eating environment and meal fellowship. These factors contain qualitative dimensions, which affect elderly people's appetites as well as their quality of life to a varying extent. Through this, it can be seen that there is a connection between their desire or willingness to eat and their will to live.
Older patients awaiting emergency department treatment
Authors: Kihlgren Annica Larsson , Nilsson Margareta , Skovdahl Kirsti , Palmblad Bert , Wimo Anders
Published: May 2004

The aim of this study was to describe, through observations and interviews with patients ≥75 years old and the relatives who accompanied them to the hospital, the conditions at the emergency department (ED) and the events that took place during the waiting period. Twenty older patients were studied, together with their relatives. A modification of a comparative design, the interpretative method ‘grounded theory’, was utilized. Open, nonparticipant observations were carried out; from the time patients were admitted until the time they were discharged. Patients were observed through all stages, for example, in the reception area, in the examination room, and in the X‐ray department. The observations were supplemented with field notes and interviews with the older patients as they left the ED. The selective coding developed into six core‐variables that were the focus of the material. These were: unpleasant waiting, unnecessary waiting, lack of good routines during the waiting stage, suffering during the waiting stage, bad feelings during the waiting stage and nursing care during the waiting stage. The way, in which nursing care was carried out, which in this context is discussed in terms of praxis and poieses, appeared to be of major importance for the older peoples’ experiences when visiting the ED.
Factors associated with the attitudes and expectations of patients suffering from β‐thalassaemia: a cross‐sectional study
Authors: Vardaki Maria A. , Philalithis Anastas E. , Vlachonikolis Ioannis
Published: May 2004

Regular transfusions and iron chelation therapy have transformed the life expectancy of homozygous β‐thalassaemia patients, so that it can now be considered a chronic condition. A health questionnaire survey of all adults suffering from β‐thalassaemia major receiving treatment on the Island of Crete, Greece was carried out with the aim of ascertaining the factors that are associated with their attitudes and expectations. The responses of 67 of the 72 patients, aged 18–45 years, were analyzed using Principal Component Analysis to extract three component indicators (Adaptability, Optimism and Pessimism Indicators), which reflected their attitudes towards life and two component indicators (Healing and Therapy Indicators) that reflected their expectations from life. These were then tested against the respondents’ socio‐demographic characteristics, their health status and satisfaction with the services. It was found that the Optimism Indicator was associated with a positive comparative assessment of health status, while the Adaptability Indicator was associated with a positive subjective assessment of health status. The Adaptability Indicator was also higher in those satisfied with the services but it was lower in the best‐educated group. The pessimism indicator was associated with a negative comparative assessment of health status and with the lowest level education. The expectation indicators showed an interaction with gender and other parameters such as admission to hospital. The relationship between the attitudes and the expectations of patients suffering from a chronically disability condition and specific experiences during their treatment regimens raises several issues related to the need for better health education and psychological support of the group of patients, as well as issues related to the communication skills of the staff caring for them.
What do men who are at risk of osteoporosis know about osteoporosis in developing countries?
Authors: Cindaş Abdullah , Savaş Serpil
Published: May 2004

The aim of this study was to investigate the knowledge, health beliefs and the knowledge sources of osteoporosis in Turkish males who are at risk of secondary causes of osteoporosis. One hundred and sixty men who had one of the systemic diseases or drugs which negatively affects bone metabolism were included in the study. Patients were asked to fill in a self‐administered questionnaire which was modified from a validated questionnaire for Turkish female patients with osteoporosis. Twenty‐two patients (15.7%) had never heard of a disease named osteoporosis. The mean score for general knowledge was 31.86 ± 20.56 (over 100 points). Only 20 (16.9%) patients had received information from a doctor. Seventy‐three (61.8%) of the patients stated that osteoporosis may be seen in men and only 42 (35.6%) patients were aware that they had a risk factor for osteoporosis. Most of the patients were unable to identify significant risk factors. Statistically significant positive correlation was found between KOS and patients’ education levels (r = 0.453, p < 0.01). The findings in our study show that Turkish men who are at risk of osteoporosis do not have sufficient knowledge about osteoporosis and its consequences. We conclude that low education level of our patients accounts for poor osteoporosis knowledge.
Support for family carers who care for an elderly person at home – a systematic literature review
Authors: Stoltz Peter , Udén Giggi , Willman Ania
Published: May 2004

Family carers are a major source of help and assistance to the persons they provide care for. They are also major contributors to the welfare system, balancing the national health care expenditure. Increasing attention, in research as well as government policy, is being paid to their role as informal caregivers. Support to family carers seems to be a new ‘buzzword’ in Swedish Government policy. However, supporting family carers may prove to be a more complex endeavour than one initially might be led to believe. Support could here be understood as any services, assistances, education, information, attitudes, and lay or professional person's provision for the benefit of the family carer. The aim of this systematic review was to identify modes of, and scientific evidence on, support for family carers of cohabiting elderly persons. The method followed a seven‐step model: a focused research question was formulated creating a base for deriving search words and inclusion and exclusion criteria for studies. Systematic database searches identified several studies some of which were retrieved, critically appraised and classified by two independent reviewers. A total of 26 articles were finally included, revealing that family carers fear social isolation and wish to network in groups with peers, either for social or for learning needs purposes. Family carers also desire respite care. However, it is unclear whether they actually benefit from any of the above or how service provision should be attempted.
Reflecting on practice: are home visits prior to discharge worthwhile in geriatric inpatient care?
Authors: Nygård Louise , Grahn Ulrika , Rudenhammar Anna , Hydling Susanne
Published: May 2004

The discharge process of elderly clients from inpatient hospital care to their homes has lately received extensive attention but there is a lack of knowledge about the clients’ problems as experienced in the home environment and their perceptions of corresponding home interventions prior to discharge. The aim of this clinical study therefore was to illuminate from both clients’ and therapists’ perspectives, common practice occupational therapy interventions at predischarge home visits in geriatric inpatient care. Home visits were carried out together with 23 clients before discharge during which their problems and the occupational therapy interventions at home were documented. After discharge, a follow‐up home visit was carried out and the apprehensions of both parts regarding the interventions undertaken at the previous home visit were documented. In addition, a group interview was held with the nine therapists engaged in the study. The results exhibited a strong focus on physical disability, environmental issues and assistive devices. The clients were in general satisfied with the home visit interventions but their perceptions and responses to problems also differed from those of the therapists. When there was dissatisfaction, it resulted from serious delay in delivery of home modifications or devices, which posed a risk to their safety at home. For multiple reasons, both pre‐ and postdischarge home visits were found to be very important for the clients’ safety.
Psychiatric care staff's and care associates’ perceptions of the concept of quality of care: a qualitative study
Authors: Schröder Agneta , Ahlström Gerd
Published: May 2004

Quality of care is a multidimensional concept and has been given different meanings in the literature. The aim in the present study was to describe how the psychiatric care staff and care associates perceived the concept of quality of care in the case of psychiatric care. Ten staff and 10 associates were interviewed. Qualitative method with a phenomenographic approach was used for the analysis. Four descriptive categories emerged: The patient's dignity is respected, The patient's participation in the care, The patient's recovery, and The patient's care environment plays an important role. Quality of care was perceived as a positive concept and as being of great importance for the patient's health and conditions of living. The results were of importance with regard to the forthcoming development of an instrument to measure the quality of psychiatric care.
Reliability of the Body Awareness Scale‐Health
Authors: Gyllensten Amanda Lundvik , Ovesson Maria N. , Lindström Inger , Hansson Lars , Ekdahl Charlotte
Published: May 2004

In physical therapy the clinical assessment Body Awareness Scale‐Health (BAS‐H) focusing on the quality of movements and movement behaviour has previously been studied for validity. The aim of this study was to address the inter‐rater reliability and test–retest reliability in three groups. The groups assessed were: patients in psychiatric care with eating disorders (n = 26), patients in rehabilitation of prolonged musculoskeletal pain (n = 22) and healthy individuals (n = 22). Results revealed inter‐rater reliability (n = 70) of the BAS‐H total to be 79.9 % with acceptable agreement (accepting one scale‐step of difference) and 48.7% with perfect agreement. Weighted Kappa ranged between 0.34 and 0.92. Test–retest reliability (n = 54) as a mean for both raters were found to be 90.5% for the BAS‐H total with acceptable agreement and 60.4% with perfect agreement. Weighted Kappa ranged between 0.65 and 0.92. The BAS‐H seems to be a reliable assessment in the rehabilitation of patient with prolonged pain, psychiatric disorders and healthy controls when used according to the manual. The authors, however, suggest some revisions.
Registered Nurses’ perceptions of geriatric rehabilitation nursing in three Scandinavian countries
Authors: Routasalo Pirkko , Wagner Lis , Virtanen Heli
Published: May 2004

This study describes Registered Nurses’ perceptions of geriatric rehabilitation nursing as well as their experiences of working in the rehabilitation of older patients in Denmark, Finland and Norway. The aim was to gain deeper insights into how Registered Nurses think about geriatric rehabilitation nursing and how their perceptions differ in these countries. The data were collected among 600 Registered Nurses using a structured questionnaire with five background items and 88 geriatric rehabilitation nursing items. The response rate was 65%. Data analysis was with SPSS statistical software. Geriatric rehabilitation nursing was experienced as something that required knowledge and experience, patience and creativity, as well as professional skills. The nurses talked with their patients about their rehabilitation goals, but not all nurses were aware of those goals. Progress in the rehabilitation process was evaluated on a daily basis and results were noted in the patients’ records. The nurses motivated patients by giving them positive feedback, by preventing pain, by pausing to share with the patients their joy about progress, and by giving the patients the opportunity to cope with daily activities. The Registered Nurses in Denmark were more team oriented and they set out the goals in the patient's records more often than their colleagues did in Finland and Norway.
Structuring the documentation of nursing care on the basis of a theoretical process model
Authors: Kärkkäinen Oili , Eriksson Katie
Published: May 2004

The aim of this study was to develop the documentation of the substance of nursing care on the basis of a theoretical caring process model. The theory is Eriksson's caring process model and her theory of health, suffering and caring. The approach of the research task was dialogue. As a research method Koski's adaptation of Gadamer's theory of hermeneutic experience was used, in which Gadamer's hermeneutic text interpretation is divided into four phases. The phases are the explicit analysis of preunderstanding, hermeneutic dialogue, the merging of horizons and active application. The dialogue is carried on between Eriksson's theory of health, suffering and caring and clinical nursing practice and between the caring process model and nursing practice. The goal is to achieve a new scientific view on which to base the documentation of nursing care.

As a result of the dialogue a classification in accordance with Eriksson's caring‐process model is presented. In the next phase of the study the classification is piloted in a clinical context. The purpose is to obtain knowledge of whether the suggested classification describes what, according to the theory, it should describe.
Meals in nursing homes
Authors: Kofod Jens , Birkemose Anna
Published: May 2004

Undernutrition is present among 33% of nursing home residents in Denmark. Hence, it is relevant to examine the meal situation at nursing homes to single out factors that may increase or reduce the residents’ food intake. In the ongoing Danish nursing home debate it is claimed that a new type of nursing home improves the residents' meal situation with a positive effect on nutrition. The aim of this work is to test the general hypothesis that (i) residents appreciate the meal situation in these nursing homes and (ii) nutritional status of the residents is improved in this type of nursing home. This study was carried out in four Danish nursing homes at various locations in Denmark. The methods used are qualitative interviews and observations at four nursing homes in combination with measurement of body mass index (BMI) at two of the four nursing homes. Undernutrition is defined as a BMI below 20. The study could not confirm the general hypothesis, as a consistent improvement in the meal situation was not found in the nursing homes studied. But an indication of improved nutritional status was found in two of the nursing homes where the degree of undernutrition was lower than generally found in Denmark. Furthermore, the study indicated that the staff and the residents conceived the nursing homes differently.
Does treatment with gum Arabic affect experimental chronic renal failure in rats?
Authors: Ali B.H. , Alqarawi A.A. , Ahmed I.H.
Published: May 2004

The effect of treatment with gum Arabic in rats with experimental chronic renal failure (CRF) was investigated. Some rats underwent two‐stage surgical nephroectomy to induce CRF, and some were sham‐operated. Gum Arabic was then given to rats in the drinking water at doses of 3 or 6 g/100 mL/day for five consecutive weeks. Thereafter, rats were killed and the concentrations of urea and creatinine measured in their plasma. Body weights of all rats were taken every week during the experimental period. The significant increases in the concentrations of urea and creatinine, induced by experimental CRF were slightly and insignificantly (P > 0.05) decreased by gum Arabic by about 8 and 13% in rats treated at doses of 3 and 6 g/100 mL/day in the drinking water, respectively. Treatment with gum Arabic at the two doses did not significantly reverse the decrease in body weight in CRF rats.
Glucose levels observed in daily clinical practice induce endothelial dysfunction in the rabbit macro‐ and microcirculation
Authors: Gomes Marília B. , Affonso Felipe S. , Cailleaux Solange , Almeida Andressa L. F. , Pinto Leonardo F. C. , Tibiriçá Eduardo
Published: May 2004

We investigated whether different concentrations of elevated glucose – corresponding to levels observed in patients with type 2 diabetes under routine care (post‐prandial mean and maximum values) and those used for diagnosing diabetes – induce impairment of vascular reactivity of the macro‐ and microcirculation in non‐diabetic rabbits. Aortic rings and isolated perfused kidneys from normal rabbits were acutely exposed (3 h) to normal (5.5 mm) or high (7–25 mm) d‐glucose concentrations. Vascular reactivity was evaluated with endothelium‐dependent [acetylcholine (ACh) and bradykinin (BK)] and independent [sodium nitroprusside (SNP)] vasodilating agents. Endothelium‐dependent relaxation of the thoracic aorta induced by ACh or BK was significantly attenuated after a 3‐h exposure to high d‐glucose (15–25 mm) but not after corresponding increased osmolarity with mannitol solutions. Relaxation induced by SNP (endothelium‐independent) was not affected by high d‐glucose concentrations. Moreover, endothelium‐dependent but not independent vasodilation of the isolated rabbit kidney was also impaired after 3‐h perfusion with high d‐glucose (11.1–25 mm). Perfusion with mannitol solutions (15–25 mm) partially blunted endothelium‐dependent renal vasodilation. It is concluded that acute hyperglycemia corresponding to post‐prandial levels in patients with type 2 diabetes induces endothelial dysfunction of conduit vessels as well as of the renal circulation of non‐diabetic rabbits.
Learning to make sense: the use of critical incident analysis in facilitated reflective groups of mental health student nurses
Authors: Gould Brian , Masters Hugh
Published: May 2004

Encouragement for nurses to utilize reflective approaches has come from a wide range of professional and educational bodies. The benefits of reflection are usually stated in terms of increases in the nurse's critical abilities and a greater awareness of the complexity of nursing practice. Within mental health nursing, additional benefits are cited in terms of improvements in interpersonal effectiveness. This small‐scale study attempted to evaluate practice‐based critical incidents brought to reflective groups by mental health nursing students The findings indicated that the ability of students to bring incidents to groups was influenced by the dynamics of the group and the group member's relationship with their facilitator. The critical incidents themselves were characterized by accounts of difficulties in relationships between students and clients. In particular, students described their concerns in making the transition from a social to a therapeutic relationship with clients. The reflective groups were used by students to give and receive support and in helping them to develop an understanding of what a professional role involved. The conclusion of the study highlights both personal and professional advantages in using reflective groups during practice placements for mental health nursing students. The critical incident approach proved helpful in focusing students on personal experiences of practice, but limitations in utilizing the reflective cycle when exploring critical incidents are highlighted. Training and ongoing support for group facilitators is essential if the learning potential of critical incidents is to be fully exploited.
Learning from contemporary practice: an exploration of clinical supervision in physiotherapy
Authors: Sellars Julie
Published: May 2004

The concept of clinical supervision as a means of professional learning and support is well known within some health and social care professions, but there is a dearth of literature related to clinical supervision and physiotherapy. The aim of this article was to report the findings of an exploratory study of clinical supervision in physiotherapy. A mixed methodological approach was adopted, through the use of self‐administered questionnaires supplemented by a small number of interviews. The findings suggest that clinical supervision is not widespread and where it has been implemented it is difficult to sustain. Different structural models were adopted in different locations. The data revealed that support for continuing professional development was a highly rated purpose for clinical supervision. Respondents used supervision for different purposes at different times depending on their individual needs, suggesting that no single model is suitable for all occasions. Any model adopted must be flexible enough to suit the needs of both the individual and the organization. Proctor's identification of the normative, formative and restorative functions of clinical supervision appears to fit current aspirations and practices very well. Support and enthusiasm for clinical supervision was high. Respondents expressed a need to take time for supervision and also valued the time it gave them; but heavy workloads, busy schedules and staff shortages frequently meant that supervision was not seen as a priority.
Disability‐specific preparation programme plays an important role in shaping students’ attitudes towards disablement and patients with disabilities
Authors: Chenoweth Lynn , Pryor Julie , Jeon Yun‐Hee , Hall‐Pullin Laynie
Published: May 2004

The philosophy of a curriculum can influence nursing students’ attitudes to particular patient groups. Despite nursing claiming to focus on meeting the needs of all, the development of an understanding of patients with disabilities is one area that is generally not given specific attention in undergraduate nursing curricula. A small pilot study was conducted to explore the effect of a clinical placement in a rehabilitation setting on nursing students’ attitudes towards, and effectiveness in caring for, adult patients with acquired disabilities from head and spinal injuries. The students arrived with unexpectedly positive attitudes towards persons with a disability, which remained relatively unchanged at the end of the clinical placement. This article reports on the pre/post‐test results of the students’ attitude changes employing the Attitudes Towards Disablement Scale (ATDS) and the Scale of Attitudes Towards Disabled Persons (SADP). The students’ participation in a disability‐specific preparation programme, prior to the placement, may explain these findings, thereby supporting other studies that report the value of such programmes in increasing positive attitudes to persons with disability.
Learning disability nursing: a multi‐method study of education and practice
Authors: Manthorpe Jill , Alaszewski Andy , Motherby Elaine , Gates Bob , Ayer Sam
Published: May 2004

This article reports on multi‐agency and multi‐disciplinary education and practice in the area of learning disability nursing in England. It draws on evidence from a national survey, commissioned by the English National Board for Nursing, Midwifery and Health Visiting (ENB), and an analysis of documents related to the professional education of these nurses, together with observation of their practice. Messages for educationalists, service commissioners, policy makers and learning disability nurses are identified from this study of a professional group that has a long tradition of working with other professionals and in a multi‐agency context.
Estimation of Electric Charge Output for Piezoelectric Energy Harvesting
Authors: Sodano H. A. , Park G. , Inman D. J.
Published: May 2004

Abstract:  Piezoelectric materials (PZT) can be used as mechanisms to transfer mechanical energy, usually ambient vibration, into electrical energy that can be stored and used to power other devices. With the recent advances in wireless and micro‐electro‐mechanical‐systems (MEMS) technology, sensors can be placed in exotic and remote locations. As these devices are wireless it becomes necessary that they have their own power supply. The power supply in most cases is the conventional battery; however, problems can occur when using batteries because of their finite life span. Because most sensors are being developed so that they can be placed in remote locations such as structural sensors on a bridge or global positioning service (GPS) tracking devices on animals in the wild, obtaining the sensor simply to replace the battery can become a very expensive task. Furthermore, in the case of sensors located on civil structures, it is often advantageous to embed them, making access impossible. Therefore, if a method of obtaining the untapped energy surrounding these sensors was implemented, significant life could be added to the power supply. One method is to use PZT materials to obtain ambient energy surrounding the test specimen. This captured energy could then be used to prolong the power supply or in the ideal case provide endless energy for the sensors lifespan. The goal of this study is to develop a model of the PZT power harvesting device. This model would simplify the design procedure necessary for determining the appropriate size and vibration levels necessary for sufficient energy to be produced and supplied to the electronic devices. An experimental verification of the model is also performed to ensure its accuracy.
Evaluation of friction in the hot rolling of steel bars by means of on line forward slip measurements
Authors: Lundberg Sven‐Erik
Published: May 2004

In spite of the importance of friction it is still a weak point in the analysis of rolling. Most studies assume that a coefficient of friction (μ) is representative for the roll gap. Forward slip measurements under normal production conditions in a bar mill have been used to evaluate the coefficient of friction, completed by laboratory measurements in a high‐temperature test rig, and stability measurements in oval–square and flat–edge oval pass sequences. Coefficients of friction in the range 0.35–0.40 have been evaluated from the forward slip measurements. The rolling speed did not exceed 0.2 m/s and measurements were made in the temperature range 1000–1150°C. No clear influence of temperature on friction could be observed. The stability measurements show similar results. However, no tests have been made at temperatures other than 1000°C, and no influence of temperature on friction can be evaluated. In the high‐temperature test rig the influence of temperature on friction is strong at temperatures exceeding 900°C, and probably the mechanism of friction changes in the test rig at higher temperatures, due to the lack of plastic deformation in the contact zone. Further investigations are necessary to formulate a relevant model for friction, valid for the entire range of parameters in a bar or wire rod mill.
Prediction of submerged arc weld‐metal composition from flux ingredients with the help of statistical design of mixture experiment
Authors: Kanjilal P. , Majumdar S. K. , Pal T. K.
Published: May 2004

A prediction model has been developed for submerged arc weld‐metal chemical composition in terms of flux ingredients with the help of statistical experiments for mixture (extreme vertices design). Bead‐on‐plate weld deposits as per statistical mixture design experiments were performed at the following welding parameters: current (400 A), voltage (26 V), speed (4.65 mm/s) and electrode extension (30 mm) using CaO–MgO–CaF2–Al2O3 flux system. The results show that some of the individual flux ingredients and their binary mixtures have a predominant effect on weld‐metal oxygen, manganese, silicon, sulphur, nickel and carbon content. The predicted results show a reasonably good agreement with the experimental results, which were obtained by performing the actual experiments based on a randomly designed flux. Analysis of the experimental data indicate that several mechanisms such as basicity index, oxygen potential, oxide stability, viscosity, electrode chemical reaction, kinetics of slag–metal reaction, etc. are operating simultaneously to yield the final weld‐metal composition.
Determination of inclusion characteristics in ‘low‐carbon’ steel during up‐hill teeming
Authors: Eriksson R. , Jönsson P. , Gustafsson A.
Published: May 2004

Clean steel production requires good control of the size distribution and the composition of the inclusions at all stages of the steel making process. So far, there exists very little information on the behavior of the inclusion population during ingot casting of steel. Therefore, this study focus on providing information on the inclusion population before and during up‐hill teeming of ‘low‐carbon’ steel, based on plant trails carried out at Ovako Steel's facilities in Hofors, Sweden. Liquid steel samples were acquired from the casting ladle just before the start of the filling of the ingot molds and from the rising steel in the molds during the filling of the molds. Thereafter, the inclusion compositions for the different size classes were determined using a scanning electron microscope equipped with energy dispersive X‐ray. It was found that the inclusion compositions were more complex in the samples taken in the mold in comparison to the ones taken in the ladle. In some cases large exogenous inclusions most likely formed due to a reaction with the mold flux were found. When a mold was filled without mold flux reoxidation of the steel due to reaction with the atmosphere took place. The inclusion size distributions were also determined using light optical microscopy and classified according to the Swedish standard SS111116 (JK chart II). The number of inclusions found in the sample taken in the mold were higher than in the sample taken in the ladle. The general conclusions are that more in‐depth research is necessary to understand the reactions taking place during filling of an ingot.
Differential thermal analysis of the iron–platinum system
Authors: Fredriksson Patrik
Published: May 2004

In the present work, a phase diagram investigation of binary Fe–Pt alloys was carried out by means of the differential thermal analysis method. 12 different alloys were investigated with a NETZSCH STA 449C Jupiter© DCS unit in the temperature range of 300–1673 K and 3 alloys with a Setaram HTC 1800 K–DSC 2000 K calorimeter in the temperature range of 300–1988 K, respectively. The measurements were carried out in Ar as well as H2 atmospheres. The results obtained show a good agreement with previous investigations and bring new information for order/disorder phase transitions for FePt and FePt3 alloys, respectively, in the temperature range 1420–1610 K. Use of He instead of H2 in some of the trials showed that the impact of hydrogen on the measurements was insignificant.
Production of zirconia from zircon using a plasma‐rotating furnace
Authors: Yuan Zhangfu , Li Wenbing , Liu Jianxun , Luo Min , Liu Jishen
Published: May 2004

Desilicated zirconia (88.60–94.21 mass% ZrO2) and stabilized zirconia (ZrO2≥ 91.54 mass%, MgO ≤ 5.39 mass%) have been produced successfully from zircon in a 150 kW plasma facility. Effects of temperature, time and carbon content on the removal of SiO2 from zircon have been investigated. According to preliminary applications in continuous‐casting nozzles at a steel works, the obtained desilicated ZrO2 can substitute for traditional ZrO2 made by the chemical‐purifying method. The main characteristics of the trial product meet the requirements for industrial production.
Use of an optimisation model for the burden calculation for the blast furnace process
Authors: Andersson A. J. , Andersson M. A. T. , Jönsson P. G.
Published: May 2004

The aim of a burden calculation in the blast furnace process is to compute the amounts of burden materials to be charged for obtaining desired hot‐metal and slag composition. Burden calculations are normally based on trial‐and‐error instead of optimisation. In this study, the use of an optimisation model for a typical blast furnace operation is presented. The yield factors of some components, such as Mn, Si, S, P and V, used in the model have been determined. The more common distribution coefficients have also been studied. Both the yield factor and distribution coefficient values were generally good and showed stable behaviour for repeated periods under similar operational conditions. In this study, the model was found to be an excellent tool for determining burden material amounts and hot‐metal and slag compositions for a blast furnace under steady and normal operation conditions. Using an optimising burden calculation model is time efficient, because it demands only 1 calculation procedure instead of a couple calculations as in the case with a trial‐and‐error method.
Differences in activity‐dependent hyperpolarization in human sensory and motor axons
Authors: Kiernan Matthew C. , Lin Cindy S.‐Y. , Burke David
Published: May 2004

The present study was undertaken to determine whether activity‐dependent changes in axonal excitability are greater in motor axons than cutaneous afferents for the same impulse load. In nine healthy subjects, supramaximal stimulation at 8 Hz was delivered to the median nerve at the wrist. Changes in the threshold current required to generate compound motor and sensory potentials ∼50% of maximum and other indices of axonal excitability were tracked before and after repetitive stimulation for 10 min. The long‐lasting stimulation produced a prolonged depression in the excitability of both cutaneous afferents and motor axons, with gradual recovery to control levels over 15–20 min. These changes in threshold were associated with a reduction in refractoriness, an increase in supernormality and a decrease in the strength–duration time constant, changes consistent with axonal hyperpolarization. Greater changes in threshold occurred in motor axons: threshold increased by 9.9% and 16.4% for test stimulus durations of 0.1 and 1 ms, respectively, for motor axons and by 5.4% and 8.3% for cutaneous afferents. With higher stimulus frequencies and thereby greater impulse loads, greater threshold changes could be induced in cutaneous afferents. It is argued that the hyperpolarization resulted from activity of the electrogenic Na+–K+ pump, that it requires > 125 ms to restore the resting state following an action potential, and that significant intracellular Na+ accumulation occurs during a steady 8‐Hz train. These findings imply that physiological discharge rates will activate the pump and thereby produce axonal hyperpolarization, the extent of which will vary with impulse load. A plausible explanation is that greater activity‐dependent hyperpolarization in motor axons is due to less inward rectification as a result of less activity of the hyperpolarization‐activated cation conductance (IH) than in cutaneous afferents.
Phasic spike patterning in rat supraoptic neurones in vivo and in vitro
Authors: Sabatier Nancy , Brown Colin H. , Ludwig Mike , Leng Gareth
Published: May 2004

In vivo, most vasopressin cells of the hypothalamic supraoptic nucleus fire action potentials in a ‘phasic’ pattern when the systemic osmotic pressure is elevated, while most oxytocin cells fire continuously. The phasic firing pattern is believed to arise as a consequence of intrinsic activity‐dependent changes in membrane potential, and these have been extensively studied in vitro. Here we analysed the discharge patterning of supraoptic nucleus neurones in vivo, to infer the characteristics of the post‐spike sequence of hyperpolarization and depolarization from the observed spike patterning. We then compared patterning in phasic cells in vivo and in vitro, and we found systematic differences in the interspike interval distributions, and in other statistical parameters that characterized activity patterns within bursts. Analysis of hazard functions (probability of spike initiation as a function of time since the preceding spike) revealed that phasic firing in vitro appears consistent with a regenerative process arising from a relatively slow, late depolarizing afterpotential that approaches or exceeds spike threshold. By contrast, in vivo activity appears to be dominated by stochastic rather than deterministic mechanisms, and appears consistent with a relatively early and fast depolarizing afterpotential that modulates the probability that random synaptic input exceeds spike threshold. Despite superficial similarities in the phasic firing patterns observed in vivo and in vitro, there are thus fundamental differences in the underlying mechanisms.
Desensitization of the mGluR6 transduction current in tiger salamander On bipolar cells
Authors: Nawy Scott
Published: May 2004

Light depolarizes retinal On bipolar cells, opening the cation‐selective channels that are responsible for producing the synaptic current. In this study, the basic features of light‐induced signals were mimicked by bathing slices of salamander retina with an agonist for the mGluR6 receptor that is expressed on the dendrites of On cells, and then displacing the agonist with the mGluR6 antagonist (RS)‐a‐cyclopropyl‐4‐phosphonophenylglycine (CPPG). The transduction current that is activated by this protocol rapidly shuts off, or desensitizes. Desensitization was highly correlated with the concentration and the type of Ca2+ buffer that was dialysed into the cell: When Ca2+ buffering was minimized by dialysing cells with 0.5 mm EGTA, the steady‐state response was reduced to approximately 40% of the peak response. Buffering with 10 mm EGTA reduced desensitization, while BAPTA completely eliminated it. Removing external Ca2+ also prevented desensitization, suggesting that entry of  Ca2+ through the transduction channel provides the trigger. The time course of desensitization was measured by using a voltage jump protocol to rapidly increase Ca2+ influx, and could be fitted with a single time constant on the order of 1 s, in good agreement with previously published rates of desensitization to steps of light in this species. It is proposed that Ca2+‐dependent shut‐off of the On bipolar cell transduction current may contribute to the conversion of sustained to transient light responses that predominate in the inner retina.
Stability Analysis of a Moored Vessel
Authors: Umar A. , Ahmad S. , Datta T. K.
Published: May 2004

A procedure for the stability analysis of a slack mooring system is presented for periodic wave excitation by finding its approximate response using a two term harmonic balance method (HBM). The conditions for determining the local and global stability of the approximate solutions are established using Hill’s variational approach and Floquet’s theory. A number of instability phenomena are identified for the mooring system for certain frequencies of excitations which fall outside the range of frequencies obtained from the analytically derived stability boundaries. The instability phenomena include symmetry breaking bifurcation, subharmonics, 3T and 5T solutions. Even chaotic motion is exhibited under certain cases.
Quantum states in a crossed wire system
Authors: Paranjape V. V.
Published: May 2004

I have calculated the energy and the wave function of an electron trapped near the intersection of two quantum wires. I have also shown that when the trapped electron is subjected to a magnetic field, the energy of the electron increases while the size of the wave function shrinks. It can be demonstrated theoretically that the introduction of the magnetic field can lead to the release of the electron from the trapped to the freely propagating state. The effect has the potential for use as a switch or as a magnetic field sensor.
Metalorganic vapor phase diffusion using DMZn Part II: Determination of the interstitial zinc charge state from secondary ion mass spectroscopy measurements using the Boltzmann–Matano technique
Authors: Hampel C. A. , Blaauw C. , Haysom J. E. , Glew R. , Calder I. D. , Guillon S. , Bryskiewicz T. , Puetz N.
Published: May 2004

Zinc is diffused into undoped InP epitaxial layers in a metalorganic chemical vapor deposition reactor using DMZn as a source. Using an interstitial-substitutional model, the effective diffusivity of zinc in undoped InP is expressed uniquely as a function of the sum of the zinc–phosophorous vacancy complex and substitutional zinc concentrations assuming a negligible interstitial zinc concentration. Boltzmann–Matano analysis of secondary ion mass spectroscopy profiles for the total zinc concentration supports a neutral (m=0) charge on the interstitial zinc.
Interface layers in In0.532Ga0.468As/InP superlattices
Authors: Rowell N. L. , Yu G. , Lockwood D. J. , Poole P. J.
Published: May 2004

Polarized far infrared reflectance was measured at oblique incidence for InGaAs/InP superlattices grown lattice matched on InP(100) wafers by chemical beam epitaxy. The contributions to the reflectance spectrum of the phonon modes of the individual layers were resolved with a generalized analysis procedure. For very thin (0.25 nm thick) alloy layers we observed InAs-like, GaAs-like, InP-like, and GaP-like modes consistent with alternating interface layers composed of InAsP and InGaAsP and having a total thickness per period of 1.2 nm. Surprisingly, the InP spacer layers were found to be compressively strained, with the strain increasing with the layer distance from the substrate. This effect is a consequence of the uncompensated strain in the asymmetric structure of the interface layers.
High-speed Si resonant cavity enhanced photodetectors and arrays
Authors: Ünlü M. S. , Emsley M. K. , Dosunmu O. I. , Muller P. , Leblebici Y.
Published: May 2004

Over the past decade a new family of optoelectronic devices has emerged whose performance is enhanced by placing the active device structure inside a Fabry–Perot resonant microcavity [P. E. Green, IEEE Spectrum 13 (2002)]. The increased optical field allows photodetectors to be made thinner and therefore faster, while simultaneously increasing the quantum efficiency at the resonant wavelengths. We have demonstrated a variety of resonant cavity enhanced (RCE) photodetectors in compound semiconductors [B. Yang, J. D. Schaub, S. M. Csutak, D. J. Rogers, and J. C. Campbell, IEEE Photonics Technol. Lett. 15, 745 (2003)] and Si [M. K. Emsley, O. I. Dosunmu, and M. S. Ünlü, IEEE J. Selected Topics Quantum Electron. 8, 948 (2002)], operating at optical communication wavelengths ranging from 850 nm to 1550 nm. The focus of this article is on Si photodetectors and arrays. High bandwidth short distance communications standards are being developed based on parallel optical interconnect fiber arrays to meet the needs of increasing data rates of interchip communication in modern computer architecture. To ensure that this standard becomes an attractive option for computer systems, low cost components must be implemented on both the transmitting and receiving end of the fibers. To meet this low cost requirement silicon based receiver circuits are the most viable option, however, high speed, high efficiency silicon photodetectors present a technical challenge. Commercially reproducible silicon wafers with a high reflectance buried distributed Bragg reflector (DBR) have been designed and fabricated [M. K. Emsley, O. I. Dosunmu, and M. S. Ünlü, IEEE J. Selected Topics Quantum Electron. 8, 948 (2002)]. The substrates consist of a two-period, 90% reflecting, DBR fabricated using a double silicon-on-insulator (SOI) process. Resonant-cavity-enhanced (RCE) Si photodetectors have been fabricated with 40% quantum efficiency at 850 nm and a FWHM of 29 ps suitable for 10 Gbps data communications. Recently, 1×12 photodetector arrays have been fabricated, packaged, and tested with silicon based amplifiers to demonstrate the feasibility of a low cost solution for optical interconnects.
Photoluminescence measurements of Er-doped chalcogenide glasses
Authors: Allen T. W. , Hawkeye M. M. , Haugen C. J. , DeCorby R. G. , McMullin J. N. , Tonchev D. , Koughia K. , Kasap S. O.
Published: May 2004

We have investigated the photoluminescence (PL) emission spectra, photoluminescence lifetimes, and relative photoluminescence intensities of various Er-doped chalcogenide glass alloys, designed for possible use in optical waveguide amplifier applications at the telecommunications wavelength of 1550 nm. Bulk samples were prepared using melt-quenching techniques, and the samples were doped with varying amounts of Er2S3 or ErCl3, in the range of 0.3−3 at. %. Using a 980 nm pump beam, we measured the lifetime of the 1550 nm (4I13/2 to I15/24) luminescence and PL spectra. For two of the alloys, the luminescence efficiency as a function of erbium concentration was observed by scaling the luminescence intensity by the weight of each sample. For GaGeS, the luminescence lifetime exhibited quenching at concentrations of erbium greater than 1 at. %, but for GaGeSe, this behavior was not observed for concentrations as high as 3 at. %. However, the photoluminescence efficiency measurements for both glasses showed quenching at concentrations greater than 1 at. % Er. We attribute these results to ion–ion interactions, and comment on their effect on these alloys in regards to their use in waveguide amplifiers.
Techniques for achieving low leakage current in dry etched InGaAs waveguide PIN detectors
Authors: Qian Yahong Y. H. , An Serguei , Betty Ian , Rousina-Webb Roghieh , Griswold Ellen , Foster Robert , Driad Rachid
Published: May 2004

InGaAs waveguide PIN detectors require a low leakage current and adequate passivation. Removing dry-etch-induced subsurface damage and surface residues on mesa sidewalls prior to passivation is not only important in reducing these leakage currents, but it is also critical in preventing device degradation. In this article, we investigate the effects of the mesa sidewall clean treatment on the InGaAs waveguide PINs etched using a methane-based (CH4) reactive ion etch (RIE) and a hydrogen bromide-based (HBr) inductively coupled plasma etch (ICP). Post-dry-etching treatments have been developed employing a rapid thermal anneal, followed by a series of Br-, H2SO4-, and HF-based cleaning processes. Transmission electron microscopy analysis shows no apparent sidewall damage, which could cause high leakage currents. Scanning electron microscopy shows sidewall etch by-product removal and ridge CD maintenance after the wet cleaning processes. Very low leakage currents, comparable to those observed in damage-free wet-etched waveguides, were achieved using the RIE or ICP etches, followed by the combination of post dry-etch treatments. I-V measurements were used to provide a quick feedback of sidewall quality and a sensitive method for evaluating the level of damage in these devices as compared to other analytical techniques.