Periodic breathing during ascent to extreme altitude quantified by spectral analysis of the respiratory volume signal

High altitude periodic breathing (PB) shares some common pathophysiologic aspects with sleep apnea, Cheyne-Stokes respiration and PB in heart failure patients. Methods that allow quantifying instabilities of respiratory control provide valuable insights in physiologic mechanisms and help to identify therapeutic targets. Under the hypothesis that high altitude PB appears even during physical activity and can be identified in comparison to visual analysis in conditions of low SNR, this study aims to identify PB by characterizing the respiratory pattern through the respiratory volume signal. A number of spectral parameters are extracted from the power spectral density (PSD) of the volume signal, derived from respiratory inductive plethysmography and evaluated through a linear discriminant analysis. A dataset of 34 healthy mountaineers ascending to Mt. Muztagh Ata, China (7,546 m) visually labeled as PB and non periodic breathing (nPB) is analyzed. All climbing periods within all the ascents are considered (total climbing periods: 371 nPB and 40 PB). The best crossvalidated result classifying PB and nPB is obtained with Pm (power of the modulation frequency band) and R (ratio between modulation and respiration power) with an accuracy of 80.3% and area under the receiver operating characteristic curve of 84.5%. Comparing the subjects from 1(st) and 2(nd) ascents (at the same altitudes but the latter more acclimatized) the effect of acclimatization is evaluated. SaO(2) and periodic breathing cycles significantly increased with acclimatization (p-value < 0.05). Higher Pm and higher respiratory frequencies are observed at lower SaO(2), through a significant negative correlation (p-value < 0.01). Higher Pm is observed at climbing periods visually labeled as PB with > 5 periodic breathing cycles through a significant positive correlation (p-value < 0.01). Our data demonstrate that quantification of the respiratory volume signal using spectral analysis is suitable to identify effects of hypobaric hypoxia on control of breathing.

A proteome signature for intrauterine growth restriction derived from multifactorial analysis of mass spectrometry-based cord blood serum profiling

Intrauterine growth restriction (IUGR) is defined as a condition in which the fetus does not reach its genetically given growth potential, resulting in low birth weight. IUGR is an important cause of perinatal morbidity and mortality, thus contributing substantially to medically indicated preterm birth in order to prevent fetal death. We subjected umbilical cord blood serum samples either belonging to the IUGR group (n = 15) or to the control group (n = 15) to fractionation by affinity chromatography using a bead system with hydrophobic interaction capabilities. So prepared protein mixtures were analyzed by MALDI-TOF mass spectrometric profiling. The six best differentiating ion signals at m/z 8205, m/z 8766, m/z 13 945, m/z 15 129, m/z 15 308, and m/z 16 001 were collectively assigned as IUGR proteome signature. Separation confidence of our IUGR proteome signature reached a sensitivity of 0.87 and a specificity of 0.93. Assignment of ion signals in the mass spectra to specific proteins was substantiated by SDS-PAGE in conjunction with peptide mass fingerprint analysis of cord blood serum proteins. One constituent of this proteome signature, apolipoprotein C-III(0) , a derivative lacking glycosylation, has been found more abundant in the IUGR cord blood serum samples, irrespective of gestational age. Hence, we suggest apolipoprotein C-III(0) as potential key-marker of the here proposed IUGR proteome signature, as it is a very low-density lipoprotein (VLDL) and high-density lipoprotein (HDL) member and as such involved in triglyceride metabolism that itself is discussed as being of importance in IUGR pathogenesis. Our results indicate that subtle alterations in protein glycosylation need to be considered for improving our understanding of the pathomechanisms in IUGR.

[Seasonal fluctuations and influence of nutrition on macular pigment density]

PURPOSE: We have previously reported on measuring macular pigment density (MPD) with a scanning laser ophthalmoscope (HRA, Heidelberg Engineering, Heidelberg, Germany). This study war undertaken to evaluate the variation of MPD over a period of 1 year in healthy subjects. METHOD: We used autofluorescence images recorded with a HRA to evaluate MPD with a 2 degrees circle centered on the fovea. Healthy subjects were included in the study and MPD measurements were repeated every 2 months over a period of 1 year. RESULTS: We included a total of 30 healthy subjects aged 19-34 years (mean: 23+/-2 years). Mean MPD at time point 1 was 0.215+/-0.056 density units (DU), at time point 2 0.235+/-0.051 DU, at time point 3 0.218+/-0.055 DU, at time point 4 0.228+/-0.057 DU, at time point 5 0.225+/-0.053 DU, and at time point 6 0.203+/-0.050 DU. The statistical analysis revealed no significant variation of MPD over the follow-up period of 1 year. CONCLUSION: This study demonstrates that MPD shows no variation over a period of 1 year in healthy subjects.

Resonance frequency analysis in relation to jawbone characteristics and during early healing of implant installation

OBJECTIVES: To monitor resonance frequency analysis (RFA) in relation to the jawbone characteristics and during the early phases of healing and incorporation of Straumann dental implants with an SLA surface. MATERIAL AND METHODS: 17 Straumann 4.1 mm implants (10 mm) and 7 Straumann 4.8 mm implants (10 mm) were installed and ISQ determined at baseline and after 1, 2, 3, 4, 5, 6, 8 and 12 weeks. Central bone cores were analyzed from the 4.1 mm implants using micro CT for bone volume density (BVD) and bone trabecular connectivity (BTC). RESULTS: Pocket probing depths ranged from 2-4 mm and bleeding on probing from 5-20%. At baseline, BVD varied between 24% and 65% and BTC between 4.9 and 25.4 for the 4.1 mm implants. Baseline ISQ varied between 55 and 74 with a mean of 61.4. No significant correlations were found between BVD or BTC and ISQ Values. For the 4.8 mm diameter implants baseline ISQ values ranged from 57-70 with a mean of 63.3. Over the healing period ISQ values increased at 1 week and decreased after 2-3 weeks. After 4 weeks ISQ values, again increased slightly, no significant differences were noted over time. One implant (4.1 mm) lost stability at 3 weeks. Its ISQ value had dropped from 68 to 45. However the latter value was determined after the clinical diagnosis of instability. CONCLUSION: ISQ values of 57-70 represented homeostasis and implant stability. However no predictive value for loosing implant stability can be attributed to RFA since the decrease occurred after the fact.

Resonance Frequency Analysis (RFA) during early healing

Objectives: - to monitor resonance frequency analysis (RFA) in relation to the jawbone characteristics during the early phases of healing and incorporation of Straumann® dental implants with an SLA surface. Material and methods: 17 Straumann 4.1mm implants (10mm) and 7 Straumann 4.8mm implants (10mm) were installed and ISQ determined at baseline and after 1, 2, 3, 4, 5, 6, 8 and 12 weeks. Central bone cores were analyzed from the 4.1mm implants using micro CT for bone volume density (BVD) and bone trabecular connectivity (BTC). Results: Pocket probing depths ranged between 2-4mm and bleeding on probing between 5-20%. At baseline, BVD varied between 24 and 65% and BTC between 4.9 and 25.4 for the 4.1mm implants. Baseline ISQ varied between 55 and 74 with a mean of 61.4. No significant correlations were found between BVD or BTC and ISQ Values. For the 4.8mm diameter implants baseline ISQ values ranged from 57 – 70 with a mean of 63.3. Over the healing period ISQ values increased at 1 week and decreased after 2-3 weeks. After 4 weeks ISQ values, again increased slightly, no significant differences were noted over time. One implant (4.1mm) lost stability at 3 weeks. Its ISQ value had dropped from 68 to 45. However the latter value was determined after the clinical diagnosis of instability. Conclusion: ISQ values of 57 – 70 represented homeostasis and implant stability. However no predictive value for loosing implant stability can be attributed to RFA since decease occurred after the fact.

Beneficial effects of aggressive low-density lipoprotein cholesterol lowering in women with stable coronary heart disease in the Treating to New Targets (TNT) study

OBJECTIVE: To examine by secondary analysis of the Treating to New Targets (TNT) study whether the benefits of intensive versus standard levels of lipid lowering are equally applicable to women. METHODS: A total of 10 001 patients (1902 women) with stable coronary heart disease (CHD) were randomised to double-blind treatment with atorvastatin 10 or 80 mg/day for a median follow-up of 4.9 years. RESULTS: In women and men, intensive treatment with atorvastatin 80 mg significantly reduced the rate of major cardiovascular events compared with atorvastatin 10 mg. Among women, the relative and absolute reductions were 27% and 2.7%, respectively (hazard ratio (HR) = 0.73, 95% confidence interval (CI) 0.54 to 1.00, p = 0.049). In men, the corresponding rate reductions were 21% and 2.2% (HR = 0.79, 95% CI 0.69 to 0.91, p = 0.001). The number needed to treat value (to prevent one cardiovascular event over 4.9 years compared with patients treated with atorvastatin 10 mg) for atorvastatin 80 mg was 29 for women and 30 for men. Rates of death of non-cardiovascular origin in the atorvastatin 80 mg and atorvastatin 10 mg were 3.6% and 1.6%, respectively (p = 0.004) among women, and 2.8% and 3.1% (p = 0.47) among men. CONCLUSION: Intensive lipid-lowering treatment with atorvastatin 80 mg produced significant reductions in relative risk for major cardiovascular events compared with atorvastatin 10 mg in both women and men with stable CHD.

An analysis of the spatial and temporal patterns of highly pathogenic avian influenza occurrence in Vietnam using national surveillance data

The objectives of this study were to describe the spatio-temporal pattern of an epidemic of highly pathogenic avian influenza (HPAI) in Vietnam and to identify potential risk factors for the introduction and maintenance of infection within the poultry population. The results indicate that during the time period 2004–early 2006 a sequence of three epidemic waves occurred in Vietnam as distinct spatial and temporal clusters. The risk of outbreak occurrence increased with a greater percentage of rice paddy fields, increasing domestic water bird and chicken density. It increased with reducing distance to higher population density aggregations, and in the third epidemic wave with increasing percentage of aquaculture. The findings indicate that agri-livestock farming systems involving domestic water birds and rice production in river delta areas are important for the maintenance and spread of infection. While the government’s control measures appear to have been effective in the South and Central parts of Vietnam, it is likely that in the North of Vietnam the vaccination campaign led to transmission of infection which was subsequently brought under control.

Evaluating northern hardwood management using retrospective analysis and diameter distributions

Northern hardwood management was assessed throughout the state of Michigan using data collected on recently harvested stands in 2010 and 2011. Methods of forensic estimation of diameter at breast height were compared and an ideal, localized equation form was selected for use in reconstructing pre-harvest stand structures. Comparisons showed differences in predictive ability among available equation forms which led to substantial financial differences when used to estimate the value of removed timber. Management on all stands was then compared among state, private, and corporate landowners. Comparisons of harvest intensities against a liberal interpretation of a well-established management guideline showed that approximately one third of harvests were conducted in a manner which may imply that the guideline was followed. One third showed higher levels of removals than recommended, and one third of harvests were less intensive than recommended. Multiple management guidelines and postulated objectives were then synthesized into a novel system of harvest taxonomy, against which all harvests were compared. This further comparison showed approximately the same proportions of harvests, while distinguishing sanitation cuts and the future productive potential of harvests cut more intensely than suggested by guidelines. Stand structures are commonly represented using diameter distributions. Parametric and nonparametric techniques for describing diameter distributions were employed on pre-harvest and post-harvest data. A common polynomial regression procedure was found to be highly sensitive to the method of histogram construction which provides the data points for the regression. The discriminative ability of kernel density estimation was substantially different from that of the polynomial regression technique.

Geospatial analysis of western juniper (Juniperus occidentalis) encroachment utilizing remotely sensed data

Utilizing remote sensing methods to assess landscape-scale ecological change are rapidly becoming a dominant force in the natural sciences. Powerful and robust non-parametric statistical methods are also actively being developed to compliment the unique characteristics of remotely sensed data. The focus of this research is to utilize these powerful, robust remote sensing and statistical approaches to shed light on woody plant encroachment into native grasslands--a troubling ecological phenomenon occurring throughout the world. Specifically, this research investigates western juniper encroachment within the sage-steppe ecosystem of the western USA. Western juniper trees are native to the intermountain west and are ecologically important by means of providing structural diversity and habitat for many species. However, after nearly 150 years of post-European settlement changes to this threatened ecosystem, natural ecological processes such as fire regimes no longer limit the range of western juniper to rocky refugia and other areas protected from short fire return intervals that are historically common to the region. Consequently, sage-steppe communities with high juniper densities exhibit negative impacts, such as reduced structural diversity, degraded wildlife habitat and ultimately the loss of biodiversity. Much of today's sage-steppe ecosystem is transitioning to juniper woodlands. Additionally, the majority of western juniper woodlands have not reached their full potential in both range and density. The first section of this research investigates the biophysical drivers responsible for juniper expansion patterns observed in the sage-steppe ecosystem. The second section is a comprehensive accuracy assessment of classification methods used to identify juniper tree cover from multispectral 1 m spatial resolution aerial imagery.

The rate of outpatient cataract surgery in ten European countries: an analysis using data from the SHARE survey

BACKGROUND: The aim of this study was to determine the rates of outpatient cataract surgery (ROCS) in ten European countries and to find country-specific health indicators explaining the differences. METHODS: Using data from the Survey of Health, Ageing and Retirement in Europe (SHARE), 251 eligible respondents were identified for which cataract surgery was the last surgical procedure. The ROCS of ten countries were compared using logistic regression. The influence of the public expenditure on health as per cent of the total expenditure on health, of the number of acute care beds per 1,000 population, and of the number of practicing physicians per 1,000 population, was studied by multiple logistic regression. Additional information was obtained from country-specific opinion leaders in the field of cataract surgery. RESULTS: The ROCS differed significantly between the ten analysed European countries where Denmark had the highest (100%) and Austria the lowest (0%) rate of day care surgery. A decrease in the density of acute care beds (p < 0.0000001) and in the density of practicing physicians (p < 0.05) and an increase in the public expenditure on health as per cent of the total health expenditure (p < 0.01) lead to an increase in the ROCS. According to the opinion leaders, regulations and financial incentives also have a strong influence on the ROCS. CONCLUSIONS: The outpatient rate of cataract surgery in the ten European countries was mainly influenced by the acute-care beds density, but also by the density of practicing physicians, and by the public expenditure on health.

Waiting times for cataract surgery in ten European countries: an analysis using data from the SHARE survey

AIMS: To assess waiting times for cataract surgery and their acceptance in European countries, and to find explanatory, country-specific health indicators. METHODS: Using data from the survey of health, ageing and retirement in Europe (SHARE), waiting times for cataract surgery of 245 respondents in ten countries were analysed with the help of linear regression. The influence of four country specific health indicators on waiting times was studied by multiple linear regression. The influence of waiting time and country on the wish to have surgery performed earlier was determined through logistic regression. Additional information was obtained for each country from opinion leaders in the field of cataract surgery. RESULTS: Waiting times differed significantly (p<0.001) between the ten analysed European countries. The length of wait was significantly influenced by the total expenditure on health (p<0.01) but not by the other country specific health indicators. The wish to have surgery performed earlier was determined by the length of wait (p<0.001) but not by the country where surgery was performed. CONCLUSION: The length of wait is influenced by the total expenditure on health, but not by the rate of public expenditure on health, by the physician density or by the acute bed density. The wish to have surgery performed earlier depends on the length of wait for surgery and is not influenced by the country.

THE USE OF LIFE-CYCLE ANALYSIS TO REDUCE THE ENVIRONMENTAL IMPACT OF MATERIALS IN MANUFACTURING

This thesis is composed of three life-cycle analysis (LCA) studies of manufacturing to determine cumulative energy demand (CED) and greenhouse gas emissions (GHG). The methods proposed could reduce the environmental impact by reducing the CED in three manufacturing processes. First, industrial symbiosis is proposed and a LCA is performed on both conventional 1 GW-scaled hydrogenated amorphous silicon (a-Si:H)-based single junction and a-Si:H/microcrystalline-Si:H tandem cell solar PV manufacturing plants and such plants coupled to silane recycling plants. Using a recycling process that results in a silane loss of only 17 versus 85 percent, this results in a CED savings of 81,700 GJ and 290,000 GJ per year for single and tandem junction plants, respectively. This recycling process reduces the cost of raw silane by 68 percent, or approximately $22.6 and $79 million per year for a single and tandem 1 GW PV production facility, respectively. The results show environmental benefits of silane recycling centered around a-Si:H-based PV manufacturing plants. Second, an open-source self-replicating rapid prototype or 3-D printer, the RepRap, has the potential to reduce the environmental impact of manufacturing of polymer-based products, using distributed manufacturing paradigm, which is further minimized by the use of PV and improvements in PV manufacturing. Using 3-D printers for manufacturing provides the ability to ultra-customize products and to change fill composition, which increases material efficiency. An LCA was performed on three polymer-based products to determine the CED and GHG from conventional large-scale production and are compared to experimental measurements on a RepRap producing identical products with ABS and PLA. The results of this LCA study indicate that the CED of manufacturing polymer products can possibly be reduced using distributed manufacturing with existing 3-D printers under 89% fill and reduced even further with a solar photovoltaic system. The results indicate that the ability of RepRaps to vary fill has the potential to diminish environmental impact on many products. Third, one additional way to improve the environmental performance of this distributed manufacturing system is to create the polymer filament feedstock for 3-D printers using post-consumer plastic bottles. An LCA was performed on the recycling of high density polyethylene (HDPE) using the RecycleBot. The results of the LCA showed that distributed recycling has a lower CED than the best-case scenario used for centralized recycling. If this process is applied to the HDPE currently recycled in the U.S., more than 100 million MJ of energy could be conserved per annum along with significant reductions in GHG. This presents a novel path to a future of distributed manufacturing suited for both the developed and developing world with reduced environmental impact. From improving manufacturing in the photovoltaic industry with the use of recycling to recycling and manufacturing plastic products within our own homes, each step reduces the impact on the environment. The three coupled projects presented here show a clear potential to reduce the environmental impact of manufacturing and other processes by implementing complimenting systems, which have environmental benefits of their own in order to achieve a compounding effect of reduced CED and GHG.

Effect of once-yearly zoledronic acid 5 mg on fracture risk and change in femoral neck bone mineral density

Context: In the Health Outcomes and Reduced Incidence with Zoledronic Acid Once Yearly - Pivotal Fracture Trial (HORIZON-PFT), zoledronic acid (ZOL) 5 mg significantly reduced fracture risk. Objective: To identify factors associated with greater efficacy during ZOL 5 mg treatment. Design, Setting and Patients: Subgroup analysis (preplanned and post hoc) of a multicenter, double-blind, placebo-controlled, 36-month trial in 7765 women with postmenopausal osteoporosis. Intervention: Single infusion of ZOL 5 mg or placebo at baseline, 12 and 24 months. Main Outcome Measures: Primary endpoints: new vertebral fracture and hip fracture. Secondary endpoints: non-vertebral fracture, change in femoral neck bone mineral density (BMD). Baseline risk factor subgroups: age, BMD T-score and vertebral fracture status, total hip BMD, race, weight, geographical region, smoking, height loss, history of falls, physical activity, prior bisphosphonates, creatinine clearance, body mass index (BMI), concomitant osteoporosis medications. Results: Greater ZOL induced effects on vertebral fracture risk with younger age (treatment-by-subgroup interaction P=0.05), normal creatinine clearance (P=0.04), and BMI >/=25 kg/m(2) (P=0.02). There were no significant treatment-factor interactions for hip or non-vertebral fracture or for change in BMD. Conclusions: ZOL appeared more effective in preventing vertebral fracture in younger women, overweight/obese women and women with normal renal function. ZOL had similar effects irrespective of fracture risk factors or femoral neck BMD.

Statistical analysis of multichannel scalp field data

High density spatial and temporal sampling of EEG data enhances the quality of results of electrophysiological experiments. Because EEG sources typically produce widespread electric fields (see Chapter 3) and operate at frequencies well below the sampling rate, increasing the number of electrodes and time samples will not necessarily increase the number of observed processes, but mainly increase the accuracy of the representation of these processes. This is namely the case when inverse solutions are computed. As a consequence, increasing the sampling in space and time increases the redundancy of the data (in space, because electrodes are correlated due to volume conduction, and time, because neighboring time points are correlated), while the degrees of freedom of the data change only little. This has to be taken into account when statistical inferences are to be made from the data. However, in many ERP studies, the intrinsic correlation structure of the data has been disregarded. Often, some electrodes or groups of electrodes are a priori selected as the analysis entity and considered as repeated (within subject) measures that are analyzed using standard univariate statistics. The increased spatial resolution obtained with more electrodes is thus poorly represented by the resulting statistics. In addition, the assumptions made (e.g. in terms of what constitutes a repeated measure) are not supported by what we know about the properties of EEG data. From the point of view of physics (see Chapter 3), the natural “atomic” analysis entity of EEG and ERP data is the scalp electric field