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At least 1,621 records · Page 90Linked to original sources
PubMed2006

Landscape ecology of the Guanting Reservoir, Beijing, China: multivariate and geostatistical analyses of metals in soils.

Surface soil samples were collected from 52 sites around Guanting Reservoir in Beijing, China, and contents of 'total' metals (Cu, Zn, Pb, Cd, As, Ni and Cr) were determined. The results indicate that the degree of heavy metal pollution in the soils declines in the order of Cd>Cr>Zn>As>Cu>Ni>Pb. Based on the results of a combination of multivariate statistics and geostatiscal analyses, it was concluded that land application of phosphate fertilizer, wastewater and sludge were the primary sources of Cd and Zn in soils. Whereas As, Cu, Cr and Ni in some soils were due to natural rock weathering. The sources of Pb in soils only partially originated from land application of phosphate fertilizer, but mainly from vehicle exhaust. The greatest concentrations of all metals, except for Pb, were found in Huailai County and the towns of Yanghedaqiao and Guanting.

Arsenic↗
PubMed2004

Relationship between blood lead concentration and dietary intakes of infants from 3 to 12 months of age.

Data from a study of mother-infant pairs of low socioeconomic status living in Albany County, NY, were analyzed to determine the influence of diet and nutrition on the blood lead level of infants during the first year of life. Children's diets were assessed at 3-month intervals using a 24-h diet recall as reported by the primary caregiver. The potential impact of dietary consumption of protein, iron, zinc, calcium, vitamin D, and fat, as well as serum vitamin D and ferritin on blood lead levels at 6 and 12 months of age was examined with multivariable statistical analyses, controlling for other influences on lead levels. Neonates' blood lead levels were low at birth (geometric mean=1.6 microg/dL), and none were elevated (> or = 10 microg/dL). By 12 months, the mean blood lead for this sample was 5.1 microg/dL, and 18% of the sample had an elevated blood lead level. We observed significant inverse relationships between infants' 6-month lead level and their intake of zinc, iron, and calcium. At 12 months, low iron intake continued to be associated with higher lead levels, although zinc and calcium did not. Protein had a paradoxical effect, being associated with lower lead at 6 months, but higher lead at 12 months. Serum vitamin D and ferritin were not associated with lead levels, nor was vitamin supplement use. The results reported here emphasize the value of key minerals in the diet to reduce lead absorption during early infancy.

Diet↗
PubMed2004

Metal levels in fodder, milk, dairy products, and tissues sampled in ovine farms of Southern Italy.

We measured Cd, Cr, Hg, Mn, and Pb levels in samples of fodder, milk, dairy products, and tissues collected from 12 ovine farms in the regions of Campania and Calabria (Southern Italy). The areas in which the farms are located show different levels of anthropogenic pressure. The main purpose of this study is the identification and the analysis of relationships among metal concentrations observed in samples representative of different links in the food chain. Particularly, we apply univariate, bivariate, and multivariate statistical techniques to identify the correlation structure of our data set and to evaluate the influence of anthropogenic activity. We discuss the results, focusing the analysis on the spatial and the temporal patterns of metal concentrations.

Animal Feed↗
PubMed2006

Proteomic analysis of rat hippocampus and frontal cortex after chronic treatment with fluoxetine or putative novel antidepressants: CRF1 and NK1 receptor antagonists.

Chronic administration of antidepressants is required for their efficacy, suggesting the involvement of long-term modifications. As the impact of antidepressant treatment on the brain molecular machinery is not completely understood, we performed a proteomic analysis of rat hippocampus and frontal cortex after chronic treatment with fluoxetine, with an NK1 receptor antagonist, GR205171, and a CRF receptor 1 antagonist, DMP696. After 2D electrophoresis, protein expression levels were compared with both univariate and multivariate statistical analyses and identified by mass spectrometry. All treatments modified levels of actin isoforms, whereas both fluoxetine and GR205171 reduced synapsin II. Fluoxetine treatment increased ERK2 and NP25 and decreased vacuolar ATP synthase. After GR205171 treatment, protein disulphide isomerase A was reduced; dynamin 1 and aldose reductase increased. DMP696 modulated DRP2, pyruvate kinase, LDH and ATP synthase. Although each compound induced a specific pattern of protein modulation, data suggest that antidepressants share the ability of modulating neural plasticity.

Animals↗
PubMed2005

The therapeutic value of adrenalectomy in case of solitary metastatic spread originating from primary renal cell cancer.

INTRODUCTION: Solitary adrenal metastases occur in about 1.2-10% of renal cell cancer patients. Since the vast majority of intraadrenal lesions can be detected preoperatively, we and others have recently recommended to renounce a routine adrenalectomy during surgery of renal cell cancer. However, the impact of adrenalectomy on the patients' clinical prognosis in case of a solitary metastatic lesion within the adrenal gland remains an issue of controversial discussion. Whereas some authors suggest adrenalectomy as a potentially curative treatment option in these cases, others compare its clinical value with that of a mere lymphadenectomy. PATIENTS AND METHOD: Between 1981 and 2000, 648 patients (440 males and 208 females) underwent nephrectomy in combination with adrenalectomy in our clinic for the diagnosis of renal cell cancer. The median age at first diagnosis was 59 (range 33-84) and 60 (range 20-85) years for male and female patients, respectively. The median postoperative follow - up was 2.4 years (0.2-18 years). According to the TNM - classification system (2003) tumor stages were classified as follows: T1, 228 pat. (37%); T2, 70 pat. (11%); T3, 287 pat. (46%); T4, 37 pat. (6%). In total, 339 patients revealed regional lymph node or distant metastases at the time of the surgical treatment. Although metastases of the adrenal gland were diagnosed in 48 patients, solitary intraadrenal metastases without further systemic spread were observed in only 13 cases. Several patients' and tumor characteristics (age, tumor stage and size, the presence of regional lymph node metastases, the presence of metastatic lesions at different organ sites as well as the detection of solitary intraadrenal metastases) were correlated with the patients' overall survival by univariate and multivariate statistical analysis (logistic Cox regression analysis). RESULTS: The median long - term survival was 4.8 years for the entire cohort of patients investigated. The median long - term survival was 13.8 years and 11.7 years for patients with no evidence of metastatic spread as well as for patients with a solitary intraadrenal metastatic lesion, respectively. Accordingly, the long - term survival rates at 5 and 10 years after surgery were 66%/50% and 51%/51% for patients with no evidence of metastatic spread or isolated intraadrenal metastases. This difference was not statistically significant. In contrast, for patients revealing lymph node or distant metastases at other organ sites, the median long - term survival was significantly decreased (lymph node metastases: 0.7 years; distant metastases: 1.2 years). DISCUSSION: For patients with a solitary intraadrenal metastatic lesion, adrenalectomy is a potentially curative treatment option. The observation that the long - term survival of the latter patients is comparable to that of patients with organ - confined disease might suggest the establishment of a separate TNM - category for patients revealing a solitary metastasis within the adrenal gland and no hint at further systemic metastatic spread.

Adrenal Gland Neoplasms↗
PubMed2006

Plasma fatty acid metabolic profiling and biomarkers of type 2 diabetes mellitus based on GC/MS and PLS-LDA.

Metabolic profiling has increasingly been used as a probe in disease diagnosis and pharmacological analysis. Herein, plasma fatty acid metabolic profiling including non-esterified fatty acid (NEFA) and esterified fatty acid (EFA) was investigated using gas chromatography/mass spectrometry (GC/MS) followed by multivariate statistical analysis. Partial least squares-linear discrimination analysis (PLS-LDA) model was established and validated to pattern discrimination between type 2 diabetic mellitus (DM-2) patients and health controls, and to extract novel biomarker information. Furthermore, the PLS-LDA model visually represented the alterations of NEFA metabolic profiles of diabetic patients with abdominal obesity in the treated process with rosiglitazone. The GC/MS-PLS-LDA analysis allowed comprehensive detection of plasma fatty acid, enabling fatty acid metabolic characterization of DM-2 patients, which included biomarkers different from health controls and dynamic change of NEFA profiles of patients after treated with medicine. This method might be a complement or an alternative to pathogenesis and pharmacodynamics research.

Adult↗
PubMed2026

Flavoromics-based profiling reveals taste and aroma differences between infant formula and breast milk.

Flavor differences between infant formula (IF) and breast milk (BM) are considered a potential factor affecting infants' acceptance of IF. This experiment employs flavoromics combined with multivariate statistical analysis to systematically compare the flavor profiles of IF and BM. Electronic tongue analysis and amino acid correlation revealed that IF was characterised by pronounced saltiness and umami richness, whereas BM exhibited greater bitterness and astringency. Volatile compound profiling identified five key flavor constituents in IF, predominantly aldehydes such as hexanal and pentanal. In contrast, BM contained a broader array of compounds-including acids, aldehydes, and esters-resulting in a more complex flavor profile. Kyoto Encyclopedia of Genes and Genomes (KEGG)-based metabolic pathway annotation, together with fatty acid profiling, suggested that some volatiles may be associated with lipid oxidation, Maillard reaction and sulfur-containing amino acid degradation pathways, offering a theoretical basis for the targeted optimisation of IF flavor.

Humans↗
PubMed2003

Multivariate chemometrics for the forensic discrimination of blue ball-point pen inks based on their Vis spectra.

Fifty blue ball-point pen inks of five different brands were examined on the basis of the Vis spectrum of their ethanolic solutions with a view to achieving good discrimination between them. Samples were dissolved in absolute ethanol and their absorbance values in the range of 400-750 nm, after appropriate transformations, were used as variables in the multivariate statistical techniques of cluster analysis (CA), principal component analysis (PCA) and discriminant analysis (DA). These techniques were used successively so that an effective and meaningful discriminant model was calculated in the final step. The initial 351 variables (log10 transformed ink absorption values at each wavelength) were subjected to a K-means CA over the objects (samples) and only 20 variables were retained. Principal component analysis was used to detect any outliers (four samples were removed) and the remaining samples were re-subjected to PCA to decide how many variables to enter into DA and whether original variables or components should be used. It was found that the first three principal components (in accordance with the Kaiser criterion) were good descriptors of the 20 original variables (96.97% of the data variance was explained) and their use as latent variables in DA lead to low average variable redundancy (33.6%) in the discriminant model. The calculated model had a Wilks' lambda of 8.98 x 10(-5) and was statistically significant at the P = 0.05 level. The post hoc classification of the training dataset was 100% correct. From the DA results and the component loadings it was found that discrimination was achieved on the basis of differences in the shape of the absorption bands as well as their relative intensities. The method was therefore deemed appropriate for supporting exclusionary forensic purposes.

Journal Article↗
PubMed2005

Characterization of gunpowder samples using time-of-flight secondary ion mass spectrometry (TOF-SIMS).

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) was utilized to obtain characteristic mass spectra from three different smokeless powders and six different black powder samples. In these mass spectra, peaks indicative of both the organic and inorganic additive constituents in the gunpowders were observed. TOF-SIMS was able to successfully differentiate between the different black and smokeless gunpowder samples analyzed with the aid of principal components analysis (PCA), a multivariate statistical analysis approach often used to reduce the dimensionality of complex data. TOF-SIMS was also used to obtain information about the spatial distribution of the various additives contained within the gunpowder samples. SIMS imaging demonstrated that that the samples could potentially be characterized by their 2-D structure, which varied from sample to sample. These results clearly demonstrate the feasibility of utilizing TOF-SIMS as a tool for the characterization and differentiation of gunpowder samples for general forensic applications.

Journal Article↗
PubMed2006

Discrimination between sediment and soil samples for forensic purposes using elemental data: an investigation of particle size effects.

This paper reports the results of an investigation to quantify variations in elemental concentrations amongst different particle size fractions obtained from a suite of sediment samples collected from the River Avon, UK. Concentrations of 49 elements determined by inductively coupled plasma spectrometry (ICP-AES and ICP-MS) were compared using conventional and multivariate statistical methods in order to assess compositional differences between different size fractions and between different samples. The results showed significant differences between different size fractions and the bulk sediments, but indicated that all of the size fractions considered (<150, 63-150, 20-63 and <20microm) provided an adequate basis on which to identify associations and differences between samples. It was concluded that, while in certain specific circumstances it may be most appropriate to make forensic comparisons based on a very narrowly defined particle size range, for the majority of purposes the <150microm fraction provides the best compromise between sample size requirements and data resolution.

Cluster Analysis↗
PubMed2006

Endurance sports is a risk factor for atrial fibrillation after ablation for atrial flutter.

INTRODUCTION: Sports activity has been associated with the development of atrial arrhythmias. Atrial fibrillation (AF) is frequently observed after successful ablation for atrial flutter. Sports activity as a risk factor for AF development after flutter ablation has not been studied. METHODS: We analyzed outcome in 137 patients (83% men) after ablation for isthmus-dependent atrial flutter (excluding patients with concomitant ablation for atrial tachycardia or fibrillation). Sports activity before and after ablation was evaluated by detailed questionnaires. Endurance sports was defined as (semi-)competitive participation in cycling, running or swimming for > or =3 h/week (and for > or =3 years pre-ablation). Median follow-up was 2.5 years. Survival free of AF was evaluated with Kaplan-Meier curves and log-rank statistics. Multivariate analysis was based on Cox proportional hazard evaluation. RESULTS: Acute ablation success was 99% and flutter recurrence 4.4%. Thirty-one patients (23%) had been regularly engaged in endurance sports before ablation and 19 (14%) continued regular sports activity afterwards. Those performing sports were slightly younger. A history of endurance sports was a significant risk factor for post-ablation AF (univariate HR 1.96 (1.19-3.22), p<0.01, and multivariate HR 1.81 (1.10-2.98), p=0.02). Also continuation of endurance sports activity after ablation showed a trend for increased risk to develop AF despite a relatively small sample size (n=19; multivariate HR 1.68 (0.92-3.06), p=0.08). Cox proportional hazard calculations revealed a 10% and 11% increased risk for AF development per weekly hour sport performed before and after ablation respectively (p<0.01 for both). CONCLUSION: A history of endurance sports activity is associated with the development of AF after ablation of atrial flutter.

Atrial Fibrillation↗
PubMed2006

The impact of admission plasma glucose on long-term mortality after STEMI and NSTEMI myocardial infarction.

UNLABELLED: Diabetes mellitus is a widely recognized risk factor for cardiovascular disease. Type 2 diabetics have a 3-fold increased risk of CAD; prediabetics, without chronic hyperglycemia, have a 2-fold increased risk compared with normal subjects. We determined in 615 consecutive acute infarction patients whether the admission plasma glucose level remains associated with major adverse cardiovascular events (MACE) in an unselected patient population with myocardial infarction. Of these, the mean age of 66+/-12 years (range 36-90) and 69% were men and mean APG and HbA1c level were 8.2+/-4.0 mmol/l and 6.1+/-1.1% respectively. 13.2% of total study population was already known with diabetes. We recorded 132 deaths (21.5%), of whom 23.6% were known diabetic patients during 2.5 years of follow-up Multivariate statistical analysis identified APG, older age and previous MI as independent mortality predictors. CONCLUSION: Increased APG levels are significantly and independently correlated with poor prognosis after myocardial infarction, and this underlines the need for better medical treatment of hyperglycemic state and aggressive screening for early detection of diabetes.

Adult↗
PubMed2006

Key functional characteristics in designing and operating health information websites for user satisfaction: an application of the extended technology acceptance model.

OBJECTIVE: With growing demand for health information and rapid development of information technology, health information websites are emerging as the most effective media to meet the public's needs for health information. This article is intended to offer a technical view on the design and operations of health information websites. Along this line, employed here is the Technology Acceptance Model (TAM), which has been widely used to predict user acceptance based on Perceived Ease-of-Use (PEOU) and Perceived Usefulness (PU). METHODS: We extend the original TAM by including some exogenous variables since it is necessary to understand the role of the antecedents of acceptance constructs when designing an effective health information website for improving user satisfaction. This study focuses on identifying the core functional factors in designing and operating health information websites. Conducted are some multivariate statistical analyses based on data from an extensive survey. RESULTS: The results from the structural equation analysis suggest that functional characteristics should be categorized into three groups: one affecting PU and PEOU, another affecting only PEOU, and the other having no direct effect on either PU or PEOU. In particular, 'usage support' and 'customization' are two key functional characteristics in the extended TAM framework for health information websites. CONCLUSION: Contrary to expectations, however, the direct effect of PEOU on usage support is hardly observed, which differentiates health information websites from other commercial websites like online shopping malls. As a result, understanding the antecedents of PU takes on more significance.

Access to Information↗
PubMed2005

Early versus delayed surgical treatment of open tibial fractures: effect on the rates of infection and need of secondary surgical procedures to promote bone union.

The purpose of this study was to evaluate whether there was any significant difference in the rates of infection and of secondary surgical procedures to promote bone union, between early(6 h or less after arrival to hospital) and delayed(more than 6 h) surgical treatment of open tibial fractures. Three hundred and eighty-three open tibial fractures were evaluated. 184 fractures had early and 199 had delayed surgical treatment. The rates of infection and secondary surgical procedures to promote bone union of the two groups were compared with univariate and multivariate statistical methods. There was no statistically significant difference between early and delayed treatment groups with respect to overall infection (53/184 versus 51/199 infection rates, P = 0.96), deep infection (8/184 versus 8/199 infection rates, P = 1.0), and rates of secondary surgical procedures to promote bone union (24/184 versus 20/198, P = 0.77). We were unable to demonstrate any significant difference in infection rates or need of secondary procedures to promote bone union, between early and delayed surgical treatment of open tibial fractures.

Adolescent↗
PubMed2005

Factors associated with insulin and narcotic independence after islet autotransplantation in patients with severe chronic pancreatitis.

BACKGROUND: For patients who suffer from severe chronic pancreatitis, total pancreatectomy can alleviate pain, and islet autotransplantation (IAT) might preserve endocrine function and circumvent the complications of diabetes. Factors that determine success after this operation have not been clearly defined. STUDY DESIGN: From 2000 to 2004, 45 total or subtotal pancreatectomies with IAT were performed. Patient characteristics, narcotic usage and insulin requirements were recorded at routine followup. Narcotic usage was standardized by conversion to morphine equivalents (MEs). Univariate and multivariate statistical analyses were performed to determine factors associated with insulin and narcotic independence. RESULTS: Forty-five patients (30 women, 15 men), with a mean age of 39 years (range 16 to 62 years) underwent total or completion (n=41) or subtotal (n=4) pancreatectomies with IAT. Forty percent of patients were insulin free after a mean followup of 18months (range 1 to 46months). Factors associated in univariate analyses with insulin independence included female gender (p=0.004), lower body weight (kg) (p=0.04), more islet equivalents per kg body weight (IEQ/kg) transfused (<0.05), lower mean insulin requirement for the first 24hours postoperation (p=0.002), and lower mean insulin requirement at discharge (p=0.0005). A multiple logistic regression using gender, body mass index, and IEQ/kg identified female gender as the only notable variable associated with insulin independence. There was a notable reduction (p < 0.0001) of postoperative MEs (mean 90 mg) compared with preoperative MEs (mean 206 mg) for the entire cohort; 58% of patients are narcotic independent. In the subset of patients with>5months followup (n=32), 23 (72%) are narcotic free, with a substantial decrease in ME usage (p=0.01). CONCLUSIONS: The likelihood of glycemic control after IAT is related to both patient characteristics and islet cell mass. Based on these data, more islet cells may be required for insulin independence than previously thought.

Adolescent↗
PubMed2006

Relationship between provider volume and postoperative complications for bariatric procedures in New York State.

BACKGROUND: Although the number of bariatric procedures has grown recently, few studies have focused on the relationship between provider volume and outcomes among patients undergoing a bariatric procedure. STUDY DESIGN: Using New York State's inpatient discharge database, we identified adults undergoing a bariatric procedure in New York State between January 1, 2003 and December 31, 2003 (n=7,868). Separate multivariable statistical models were constructed to examine the relationship between surgeon volume and hospital volume and postoperative complications (using surgeon volume cutpoints of 25, 50, 100, 150 and hospital volume cutpoints of 100, 125, 150, 200) while controlling for demographic characteristics and comorbidity. RESULTS: There was a considerably higher likelihood of postoperative complications among surgeons performing 100 or fewer bariatric procedures compared with those performing more than 100 procedures (odds ratio [OR]: 2.39, 95% CI: 1.59 to 3.59) and for those performing 150 or fewer procedures compared with those performing more than 150 procedures (odds ratio: 2.05, 95% CI: 1.29 to 3.25) after risk adjustment. Likewise, for each of the four hospital volume cutpoints, there was a notably higher likelihood of postoperative complications in the lower volume hospitals. Analyses of the interaction between surgeon and hospital volume indicated a markedly higher likelihood of postoperative complications among patients operated on by a low-volume surgeon (100 procedures or fewer) in a low-volume hospital (150 procedures or fewer) or a low-volume surgeon in a high-volume hospital than among patients operated on by a high-volume surgeon in a high-volume hospital. CONCLUSIONS: The likelihood of postoperative complications from bariatric procedures is greater for patients with low-volume surgeons or in low-volume hospitals.

Adult↗
PubMed2006

Sampling volatile compounds from natural products with headspace/solid-phase micro-extraction.

Recent advances in the development of analytical methods based on headspace/solid-phase micro-extraction (HS/SPME) of natural aroma compounds are reviewed, with special emphasis on increasing reproducibility. Representative examples of applications of HS/SPME to the determination of components at trace levels, strategies for fiber selection, and improvement of SPME sampling conditions are presented. Examples of applications to quality control and sample classification, based on aroma profiling were selected to highlight the use of multivariate statistical methods.

Biological Products↗
PubMed2005

Application of singular spectrum analysis to the smoothing of raw kinematic signals.

Motion capture systems currently used in biomechanical analysis introduce systematic measurement errors that appear in the form of noise in recorded displacement signals. The noise is unacceptably amplified when differentiating displacements to obtain velocities and accelerations. To avoid this phenomenon, it is necessary to smooth the displacement signal prior to differentiation in order to eliminate the noise introduced by the experimental system. The use of singular spectrum analysis (SSA) is presented in this paper as an alternative to traditional digital filtering methods. SSA is a novel non-parametric technique based on principles of multivariate statistics. The original time series is decomposed into a number of additive time series, each of which can be easily identified as being part of the modulated signal, or as being part of the random noise. Several examples that demonstrate the superiority of this technique over other methods used in biomechanical analysis are presented in this paper.

Acceleration↗