Swept frequency biompedance analysis for the determination of body water compartments

Bioelectrical impedance analysis, (BIA), is a method of body composition analysis first investigated in 1962 which has recently received much attention by a number of research groups. The reasons for this recent interest are its advantages, (viz: inexpensive, non-invasive and portable) and also the increasing interest in the diagnostic value of body composition analysis. The concept utilised by BIA to predict body water volumes is the proportional relationship for a simple cylindrical conductor, (volume oc length2/resistance), which allows the volume to be predicted from the measured resistance and length. Most of the research to date has measured the body's resistance to the passage of a 50· kHz AC current to predict total body water, (TBW). Several research groups have investigated the application of AC currents at lower frequencies, (eg 5 kHz), to predict extracellular water, (ECW). However all research to date using BIA to predict body water volumes has used the impedance measured at a discrete frequency or frequencies. This thesis investigates the variation of impedance and phase of biological systems over a range of frequencies and describes the development of a swept frequency bioimpedance meter which measures impedance and phase at 496 frequencies ranging from 4 kHz to 1 MHz. The impedance of any biological system varies with the frequency of the applied current. The graph of reactance vs resistance yields a circular arc with the resistance decreasing with increasing frequency and reactance increasing from zero to a maximum then decreasing to zero. Computer programs were written to analyse the measured impedance spectrum and determine the impedance, Zc, at the characteristic frequency, (the frequency at which the reactance is a maximum). The fitted locus of the measured data was extrapolated to determine the resistance, Ro, at zero frequency; a value that cannot be measured directly using surface electrodes. The explanation of the theoretical basis for selecting these impedance values (Zc and Ro), to predict TBW and ECW is presented. Studies were conducted on a group of normal healthy animals, (n=42), in which TBW and ECW were determined by the gold standard of isotope dilution. The prediction quotients L2/Zc and L2/Ro, (L=length), yielded standard errors of 4.2% and 3.2% respectively, and were found to be significantly better than previously reported, empirically determined prediction quotients derived from measurements at a single frequency. The prediction equations established in this group of normal healthy animals were applied to a group of animals with abnormally low fluid levels, (n=20), and also to a group with an abnormal balance of extra-cellular to intracellular fluids, (n=20). In both cases the equations using L2/Zc and L2/Ro accurately and precisely predicted TBW and ECW. This demonstrated that the technique developed using multiple frequency bioelectrical impedance analysis, (MFBIA), can accurately predict both TBW and ECW in both normal and abnormal animals, (with standard errors of the estimate of 6% and 3% for TBW and ECW respectively). Isotope dilution techniques were used to determine TBW and ECW in a group of 60 healthy human subjects, (male. and female, aged between 18 and 45). Whole body impedance measurements were recorded on each subject using the MFBIA technique and the correlations between body water volumes, (TBW and ECW), and heighe/impedance, (for all measured frequencies), were compared. The prediction quotients H2/Zc and H2/Ro, (H=height), again yielded the highest correlation with TBW and ECW respectively with corresponding standard errors of 5.2% and 10%. The values of the correlation coefficients obtained in this study were very similar to those recently reported by others. It was also observed that in healthy human subjects the impedance measured at virtually any frequency yielded correlations not significantly different from those obtained from the MFBIA quotients. This phenomenon has been reported by other research groups and emphasises the need to validate the technique by investigating its application in one or more groups with abnormalities in fluid levels. The clinical application of MFBIA was trialled and its capability of detecting lymphoedema, (an excess of extracellular fluid), was investigated. The MFBIA technique was demonstrated to be significantly more sensitive, (P<.05), in detecting lymphoedema than the current technique of circumferential measurements. MFBIA was also shown to provide valuable information describing the changes in the quantity of muscle mass of the patient during the course of the treatment. The determination of body composition, (viz TBW and ECW), by MFBIA has been shown to be a significant improvement on previous bioelectrical impedance techniques. The merit of the MFBIA technique is evidenced in its accurate, precise and valid application in animal groups with a wide variation in body fluid volumes and balances. The multiple frequency bioelectrical impedance analysis technique developed in this study provides accurate and precise estimates of body composition, (viz TBW and ECW), regardless of the individual's state of health.

Obstacle-free range determination for rail track maintenance vehicles

Maintenance trains travel in convoy. In Australia, only the first train of the convoy pays attention to the track sig- nalization (the other convoy vehicles simply follow the preceding vehicle). Because of human errors, collisions can happen between the maintenance vehicles. Although an anti-collision system based on a laser distance meter is already in operation, the existing system has a limited range due to the curvature of the tracks. In this paper, we introduce an anti-collision system based on vision. The two main ideas are, (1) to warp the camera image into an image where the rails are parallel through a projective transform, and (2) to track the two rail curves simultaneously by evaluating small parallel segments. The performance of the system is demonstrated on an image dataset.

Management of co-occurring substance use disorders

Reviewing the breadth of current knowledge on schizophrenia, this handbook provides clear, practical guidelines for effective assessment and treatment in diverse contexts. Leading authorities have contributed 61 concise chapters on all aspects of the disorder and its clinical management. In lieu of exhaustive literature reviews, each chapter summarizes the current state of the science; highlights key points the busy practitioner needs to know; and lists recommended resources, including seminal research studies, invaluable clinical tools, and more. Comprehensive, authoritative, and timely, the volume will enable professionals in any setting to better understand and help their patients or clients with severe mental illness.

Determination of a set of surrogate parameters to assess urban stormwater quality

This paper presents the outcomes of a research project, which focused on developing a set of surrogate parameters to evaluate urban stormwater quality using simulated rainfall. Use of surrogate parameters has the potential to enhance the rapid generation of urban stormwater quality data based on on-site measurements and thereby reduce resource intensive laboratory analysis. The samples collected from rainfall simulations were tested for a range of physico-chemical parameters which are key indicators of nutrients, solids and organic matter. The analysis revealed that [total dissolved solids (TDS) and dissolved organic carbon (DOC)]; [total solids (TS) and total organic carbon (TOC)]; [turbidity (TTU)]; [electrical conductivity (EC)]; [TTU and EC] as appropriate surrogate parameters for dissolved total nitrogen (DTN), total phosphorus (TP), total suspended solids (TSS), TDS and TS respectively. Relationships obtained for DTN-TDS, DTN-DOC, and TP-TS demonstrated good portability potential. The portability of the relationship developed for TP and TOC was found to be unsatisfactory. The relationship developed for TDS-EC and TS-EC also demonstrated poor portability.

Multiple Health Behavior Changes and Co-variation in a Telephone Counseling Trial

Background Delivering effective multiple health behavior interventions to large numbers of adults with chronic conditions via primary care settings is a public health priority. Purpose Within a 12-month, telephone-delivered diet and physical activity intervention with multiple behavioral outcomes, we examined the extent and co-variation of multiple health behavior change. Methods A cluster-randomized trial with 434 patients with type 2 diabetes or hypertension were recruited from 10 general practices, which were randomized to receive telephone counseling or usual care. Results Those receiving telephone counseling were significantly more likely than those in usual care to make greater reductions in multiple behaviors after adjusting for baseline risk behaviors (OR 2.42; 95%CI 1.43, 4.11). Controlling for baseline risk and group allocation, making changes to either physical activity, fat, vegetable, or fiber intake was associated with making significantly more improvements in other behaviors. Conclusions For patients with chronic conditions, telephone counseling can significantly improve multiple health behaviors, with behavioral changes tending to co-vary.

Co-adaptive environments : investigation into computer and network enhanced adaptable, sustainable and participatory environments

This paper presents research in response to environmental concerns we face today. In a search for a better method to manage spaces and building resources consumed excessively through traditional top-down architectural solutions, the research began by speculating that the building spaces and resources can be managed by designing architectural systems that encourage a bottom-up approach. In other words, this research investigates how to design systems that encourage occupants and users of buildings to actively understand, manage and customise their own spaces. Specific attention is paid to the participation of building users because no matter how sophisticated the system is, the building will become as wasteful as conventional buildings if users cannot, or do not want to, utilise the system effectively. The research is still in its early stages. The intension of this paper is to provide a background to the issue, discuss researches and projects relevant to, but not necessarily about, architecture, and introduce a number of hypothesis and investigations to realise adaptable, participatory and sustainable environments for users.

Co-creation in business service lifecycle management

Co-creation between customers and providers has recently gained more attention by business service providers as a promising endeavour. The different perspectives of co-creation - innovation, sourcing and marketing - are well deployed. From a provider’s point of view, the question of how to manage business services with respect to co-creation is vitally important. However, service engineering and service lifecycle management typically take a mostly internal, closed-loop approach, although a logical implication of acknowledging the value co-creation perspective on “service” would be to leverage customer and other stakeholder competences to the full extent. This paper aims at reconciling the perspectives of co-creation and makes a contribution by analysing where and how co-creation can be effectively utilised throughout the various stages of a generic business service lifecycle. The result will be a framework guiding companies in using co-creation when managing their business services.

Impact of embeddedness in co-ethnic & non co-ethnic networks on business performance : evidence from Chinese immigrant entrepreneurs in Australia

This paper investigates the research question ‘What is the effect of co-ethnic and non coethnic networking on business performance in Chinese immigrant businesses?’ The research will discuss key themes such as the extent to which Chinese immigrant entrepreneurs are embedded in co-ethnic and non co-ethnic networks and the affect of embeddedness on business performance, such as the entrepreneur’s satisfaction and business growth. Research on immigrant entrepreneurship has emerged as an important new area of inquiry within the field of entrepreneurship. The increased importance of the subject is due in part to major immigrant receiving countries, such as Australia, the United States and Canada, experiencing a high growth rate in their immigrant population. Reflecting on the existing research on immigrant entrepreneurship, it was decided to investigate the role of embeddedness on entrepreneurial business performance. This research seeks to identify the impact of embeddedness in co-ethnic and non co-ethnic networks on business performance of Chinese immigrant entrepreneurs in Australia. Chinese immigrant restaurant entrepreneurs in southeast Queensland, Australia were studied. The result expands on existing research on immigrant entrepreneurship, since the majority of immigrant entrepreneurship studies have been conducted on the United States and Canada immigrant experiences, but few have been conducted in the Australian immigrant entrepreneur context. This thesis also adds empirical testing to a research area with little empirical testing. The results indicated that embeddedness in the co-ethnic network is positively related to business performance measured by both growth and satisfaction. Embeddedness in the non co-ethnic network of the Chinese immigrant entrepreneurs in Australia did not show a similar pattern in accordance with studies conducted in the United States and Canada. This result is interesting and creates the opportunity for future research employing a comparative study.

Lifestyle factors associated concurrently and prospectively with co-morbid cardiovascular disease in a population-based cohort of colorectal cancer survivors

Aims To assess self-reported lifetime prevalence of cardiovascular disease (CVD) among colorectal cancer survivors, and examine the cross-sectional and prospective associations of lifestyle factors with co-morbid CVD. Methods Colorectal cancer survivors were recruited (n = 1966). Data were collected at approximately 5, 12, 24 and 36 months post-diagnosis. Cross-sectional findings included six CVD categories (hypercholesterolaemia, hypertension, diabetes, heart failure, kidney disease and ischaemic heart disease (IHD)) at 5 months post-diagnosis. Longitudinal outcomes included the probability of developing (de novo) co-morbid CVD by 36 months post-diagnosis. Lifestyle factors included body mass index, physical activity, television (TV) viewing, alcohol consumption and smoking. Results Co-morbid CVD prevalence at 5 months post-diagnosis was 59%, and 16% of participants with no known CVD at the baseline reported de novo CVD by 36 months. Obesity at the baseline predicted de novo hypertension (odds ratio [OR] = 2.20, 95% confidence intervals [CI] = 1.09, 4.45) and de novo diabetes (OR = 6.55, 95% CI = 2.19, 19.53). Participants watching >4 h of TV/d at the baseline (compared with <2 h/d) were more likely to develop ischaemic heart disease by 36 months (OR = 5.51, 95% CI = 1.86, 16.34). Conclusion Overweight colorectal cancer survivors were more likely to suffer from co-morbid CVD. Interventions focusing on weight management and other modifiable lifestyle factors may reduce functional decline and improve survival.

Cognitive behaviour therapy (CBT) for the treatment of co-occurring depression and substance use : current evidence and directions for future research

Issues and Approach: The high rates of co-occurring depression and substance use, and the negative impact of this on illness course and outcomes have been well established. Despite this, few clinical trials have examined the efficacy of cognitive behaviour therapy (CBT). This paper systematically reviews these clinical trials, with an aim of providing recommendations for how future research can develop a more robust evidence base for the treatment of these common comorbidities. Leading electronic databases, including PubMed (ISI) and PsychINFO (CSA), were searched for peer-reviewed journal articles using CBT for the treatment of co-occurring depression and substance use. Of the 55 articles identified, 12 met inclusion criteria and were included in the review. ---------- Key Findings: There is only a limited evidence for the effectiveness of CBT either alone or in combination with antidepressant medication for the treatment of co-occurring depression and substance use. While there is support for the efficacy of CBT over no treatment control conditions, there is little evidence that CBT is more efficacious than other psychotherapies. There is, however, consistent evidence of improvements in both depression and substance use outcomes, regardless of the type of treatment provided and there is growing evidence that that the effects of CBT are durable and increase over time during follow up. ---------- Conclusions. Rather than declaring the ‘dodo bird verdict’ that CBT and all other psychotherapies are equally efficacious, it would be more beneficial to develop more potent forms of CBT by identifying variables that mediate treatment outcomes.

Bubble rise velocity and trajectory in xanthan gum crystal suspension

An experimental set-up was used to visually observe the characteristics of bubbles as they moved up a column holding xanthan gum crystal suspensions. The bubble rise characteristics in xanthan gum solutions with crystal suspension are presented in this paper. The suspensions were made by using different concentrations of xanthan gum solutions with 0.23 mm mean diameter polystyrene crystal particles. The influence of the dimensionless quantities; namely the Reynolds number, Re, the Weber number, We, and the drag co-efficient, cd, are identified for the determination of the bubble rise velocity. The effect of these dimensionless groups together with the Eötvös number, Eo, the Froude number, Fr, and the bubble deformation parameter, D, on the bubble rise velocity and bubble trajectory are analysed. The experimental results show that the average bubble velocity increases with the increase in bubble volume for xanthan gum crystal suspensions. At high We, Eo and Re, bubbles are spherical-capped and their velocities are found to be very high. At low We and Eo, the surface tension force is significant compared to the inertia force. The viscous forces were shown to have no substantial effect on the bubble rise velocity for 45 < Re < 299. The results show that the drag co-efficient decreases with the increase in bubble velocity and Re. The trajectory analysis showed that small bubbles followed a zigzag motion while larger bubbles followed a spiral motion. The smaller bubbles experienced less horizontal motion in crystal suspended xanthan gum solutions while larger bubbles exhibited a greater degree of spiral motion than those seen in the previous studies on the bubble rise in xanthan gum solutions without crystal.

Modification and validation of a microwave-assisted digestion method for subsequent ICP-MS determination of selected heavy metals in sediment and fish samples in Agusan River, Philippines

This study investigated, validated, and applied the optimum conditions for a modified microwave assisted digestion method for subsequent ICP-MS determination of mercury, cadmium, and lead in two matrices relevant to water quality, that is, sediment and fish. Three different combinations of power, pressure, and time conditions for microwave-assisted digestion were tested, using two certified reference materials representing the two matrices, to determine the optimum set of conditions. Validation of the optimized method indicated better recovery of the studied metals compared to standard methods. The validated method was applied to sediment and fish samples collected from Agusan River and one of its tributaries, located in Eastern Mindanao, Philippines. The metal concentrations in sediment ranged from 2.85 to 341.06 mg/kg for Hg, 0.05 to 44.46 mg/kg for Cd and 2.20 to 1256.16 mg/kg for Pb. The results indicate that the concentrations of these metals in the sediments rapidly decrease with distance downstream from sites of contamination. In the selected fish species, the metals were detected but at levels that are considered safe for human consumption, with concentrations of 2.14 to 6.82 μg/kg for Hg, 0.035 to 0.068 μg/kg for Cd, and 0.019 to 0.529 μg/kg for Pb.