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PubMed2003

Automated analysis of SEM X-ray spectral images: a powerful new microanalysis tool.

Spectral imaging in the scanning electron microscope (SEM) equipped with an energy-dispersive X-ray (EDX) analyzer has the potential to be a powerful tool for chemical phase identification, but the large data sets have, in the past, proved too large to efficiently analyze. In the present work, we describe the application of a new automated, unbiased, multivariate statistical analysis technique to very large X-ray spectral image data sets. The method, based in part on principal components analysis, returns physically accurate (all positive) component spectra and images in a few minutes on a standard personal computer. The efficacy of the technique for microanalysis is illustrated by the analysis of complex multi-phase materials, particulates, a diffusion couple, and a single-pixel-detection problem.

Ceramics↗
PubMed2001

Predictors of coping efficacy, negative moods and post-traumatic stress syndrome following major trauma.

The purpose of the study was to test relationships among injury appraisals, coping, social support and outcomes of coping efficacy, mood states and post-traumatic stress syndrome. A purposive sample of 152 hospitalized patients a week following major trauma was recruited from two trauma centres. The measures included the modified Ways of Coping Scale; the brief Social Support Questionnaire; the brief Profile of Mood State; the Impact of Event Scale; and selected demographic and injury related variables. Data were analyzed by multivariate statistics. The results indicated that perceived controllability, satisfaction with social support, wishful-thinking coping and problem-focused coping were the significant predictors for coping efficacy; perceived stressfulness, problem-focused coping and wishful thinking explained a significant amount of variance in mood states; avoidance coping and wishful-thinking coping were predictors for post-traumatic stress syndrome. The moderating effects of emotion-focused coping at high and medium levels were identified.

Adaptation, Psychological↗
PubMed1989

[Prognostic factors in epithelial ovarian cancers--clinical significance of morphologic indicators].

The main factors influencing prognosis (staging, histologic classification and grading, lymphocyte infiltration etc.) in 110 patients with epithelial ovarian cancers were analysed by life table technique to obtain 5 year cumulative survival rate. Multivariate statistical analysis (Cox Model) was used in 88 patients in order to find out the most important prognostic factor. The results showed that degree of lymphocyte infiltration in the tumor was the most important; the next was clinical factors; moreover, the amount of residual tumor was more significant than staging. Specimen from reoperation revealed less lymphocyte infiltration than that from the first operation. The degree of lymphocyte infiltration as an expression of the local host defence can be used as a good prognostic indicator.

Cystadenocarcinoma↗
PubMed1997

The influence of endometriosis on the success of gamete intrafallopian transfer (GIFT).

PURPOSE: Our purpose was to evaluate the outcomes of gamete intrafallopian transfer (GIFT) therapy in patients with endometriosis. METHODS: One hundred eight GIFT cycles performed under the indication of endometriosis were compared to 156 GIFT cycles with indications of other disease entities. A maximum of seven oocytes was transferred into one or both fimbriate ends with prepared spermatozoa. Clinical pregnancy rates and outcomes were evaluated according to Mantel-Haenszel's chi-square test. Multiple logistic regression analysis was performed to determine factors influencing the success on pregnancy in the total treatment cycles. RESULTS: The anthropological variables, such as age of patients, duration of infertility, and semen grading, were comparable in both groups. The responses to controlled ovarian hyperstimulation (COH) were progressively decreased while increasing the severity of endometriosis conditions such as nonendometriosis, mild-form endometriosis, and advanced-form endometriosis patients. However, there were no significant differences in the clinical pregnancy rates (40.4, 36.7, and 41.7%, respectively), multiple pregnancy rates (34.9, 27.3, and 45.0%, respectively), and early pregnancy loss rates (27.0, 18.2, and 30.0%, respectively). Multivariate statistics of pregnancy rates that adjusted the effects of patients' age, tubal health, presence of active endometriosis and/or endometriomas, number of oocytes transferred, and quality of sperm exhibited no statistical significance between endometriosis and nonendometriosis groups. CONCLUSIONS: Our data show that patients with records of endometriosis have both a decreased ovarian response to gonadotropin stimulation and a decreased number of retrieved oocytes. Since the number of oocytes needed for the GIFT procedure is limited, pregnancy results for patients in the study group were comparable with those for patients in the control group.

Analysis of Variance↗
PubMed2006

Are there empirically supported and clinically useful subtypes of alcohol dependence?

AIMS: This paper provides an overview of several multidimensional empirically derived typologies of alcohol use disorders that have been derived primarily for research purposes in relation to their clinical utility. METHODS: Studies using multivariate statistical methods for identifying homogeneous groups of subjects were selected for inclusion. Theoretically based typologies were not included in this review. RESULTS: While formal diagnostic criteria typically identify separate categories of alcohol abuse and dependence, several studies using different statistical methods consistently suggest as many as four homogeneous types of alcoholism: a chronic/severe type, a depressed/anxious type, a mildly affected type and an antisocial type. CONCLUSIONS: Even though the longitudinal outcomes of few empirically derived subtypes have been examined, alcoholism typologies remain a viable and potentially valuable tool for investigating etiological pathways, the effectiveness of treatments and the long-term course of alcohol use disorders.

Alcohol-Related Disorders↗
PubMed1994

Effect of age on mortality in coronary artery bypass surgery in New York, 1991-1992.

The purpose of this study was to determine the effect of age on the in-hospital mortality of all 30,972 patients undergoing coronary artery bypass graft (CABG) surgery in New York in 1991 and 1992. Mortality rates were relatively low for patients 40-49, 50-59, and 60-64, 65-69, and 70-74 years old (1.10%, 1.65%, 2.17%, 2.76%, and 3.36%, respectively). However, CABG surgery mortality increased rapidly for patients 75 to 79 years old (5.28%) and patients > or = 80 years old (8.31%). To examine the independent effect of age on mortality after accounting for the effects of other significant risk factors, a multivariate statistical model was developed to identify the significant independent predictors of mortality. Age emerged as 1 of 24 significant predictors, with age > or = 75 demonstrating much higher mortality risk than lesser age. For example, the odds of an 80-year-old patient's dying in the hospital were 3.25 times the odds of a 50-year-old patient's dying in the hospital, assuming all other significant risk factors were identical.

Adult↗
PubMed2006

A study of depression and anxiety among doctors working in emergency units in Denizli, Turkey.

BACKGROUND: Major work has been carried out on the psychological well-being of emergency room doctors in the US, Canada and in other developed countries, but little has been published regarding the same in the countries in economic transition. OBJECTIVE: To determine the level of, and the factors related to, depression and anxiety among doctors working in emergency units in Denizli, Turkey. METHODS: This cross-sectional study was conducted in May 2004, using a sample of 192 doctors employed in emergency units in Pamukkale University Hospital, the City Hospital, the Social Security Hospital, private hospitals, citywide primary healthcare centres and 112 emergency services in Denizli, Turkey. Data were obtained using a self-administered questionnaire, including questions on sociodemographic characteristics and two instruments determining the level of depressive symptoms and anxiety. Logistic regression was the method chosen for multivariate statistical analysis. RESULTS: The mean (standard deviation (SD)) depression score was 10.6 (6.5) and the frequency (%) of depression was 29 (15.1). Not having any hobby and having high anxiety scores were salient factors among doctors experiencing depressive symptomatology in bivariate comparisons. Logistic regression analysis showed that not having any hobby (p = 0.07) and having increased anxiety scores (p<0.001) were positive contributors to depression scores. The mean (SD) anxiety score was 8.7 (8.2) and the frequency (%) of anxiety was 28 (14.6). Being a woman, having a low monthly income and having high depression scores contributed considerably to the anxiety of doctors in bivariate comparisons. Low monthly income (<1000 v 1000-2000 YTL) (p = 0.03), the number of years spent in emergency units (p = 0.03) and having high depression scores (p<0.001) were the factors that contributed significantly to the anxiety of doctors in the multivariate regression analysis. CONCLUSION: The considerable amount of depression and anxiety found among doctors in this study should trigger further work. Studies using more powerful designs would help to illuminate the factors leading to depression and anxiety, which result in attrition among doctors from emergency units.

Adult↗
PubMed1994

Attitudes and beliefs regarding spiritual care. A survey of cancer nurses.

Why nurses neglect spiritual care issues remains unclear. Therefore, a questionnaire designed to assess oncology nurse clinicians' attitudes and beliefs about spiritual care was mailed to a stratified, random sample of 700 Oncology Nursing Society members within the United States. Data from the 181 respondents were analyzed using descriptive and multivariate statistics (for quantitative items) and content analysis (for essay questions). Analysis of data revealed both a positive regard for spiritual care within nursing, and relationships between beliefs and attitudes about spiritual care and self-reported spiritually, religiosity, ethnicity, work role, and education. Recommendations are for inclusion of theoretical and practical aspects of spiritual care in nursing education and for further investigation of nurses' attitudes and beliefs regarding spiritual care.

Adaptation, Psychological↗
PubMed2004

A pooled analysis of eastern cooperative oncology group and intergroup trials of adjuvant high-dose interferon for melanoma.

PURPOSE: Nearly 2000 patients with stage IIB and III melanoma have participated in four multicenter, randomized trials, conducted by the Eastern Cooperative Oncology Group and the Intergroup, investigating adjuvant high-dose IFN-alpha 2b therapy. The objectives of this study were to update the analyses of each individual trial and to analyze prognostic factors and treatment effects based on pooled data. EXPERIMENTAL DESIGN: Survival and disease status were updated to April 2001. Analysis of prognostic factors using optimized statistical models was based on data from patients in E1684, E1690, E1694, and E2696. Analysis of treatment effects versus observation (Obs) was based on data from 713 patients randomized to high-dose IFN-alpha 2b (HDI) or Obs in Trials E1684 and E1690. RESULTS: Updated analysis of E1684, E1690, and E1694 confirmed their original conclusions, now at median follow-up intervals of 2.1-12.6 years. Based on two-sided univariate log-rank analysis of pooled data from E1684 and E1690 (median follow-up, 7.2 years), relapse-free survival (RFS)-but not overall survival (OS)-was significantly prolonged (two-sided log-rank P value = 0.006) for patients treated with HDI versus Obs. Among all patients, prognostic factors that significantly negatively impacted RFS and OS included ulceration, recurrent disease at entry, enrollment in E1684, and age > 49 years. Multivariate statistical models adjusting for these factors confirmed the statistically significant RFS benefit of HDI versus Obs but did not demonstrate a significant OS benefit in the pooled populations. CONCLUSIONS: In patients with high-risk resected melanoma, HDI is effective adjuvant therapy with strong evidence for improved RFS and evidence for moderate improvement in OS based on two prospective randomized studies but not the pooled analysis. Analyses of predictors of relapse and response are now needed to improve the therapeutic value of this modality.

Adult↗
PubMed1990

The variability of patterns of sexual dimorphism in the hominoid skull.

Univariate and multivariate statistical analyses are applied to a number of cranial dimensions and angles from living hominoids in order to investigate the patterns of sexual dimorphism in these groups. Clear differences in patterns of cranial sexual dimorphisms are demonstrated not only between genera but also within a single species (Homo). These differences overlay the common finding of a sexual size difference in all groups. The results imply that caution is required in using the sexual dimorphisms of living hominoids as models for those anticipated in fossils.

Animals↗
PubMed1990

[Classification of glucose-6-phosphate dehydrogenase enzymopathies: evaluation of kinetic parameters using multivariate methods].

The dependence between 9 kinetic parameters of glucose-6-phosphate dehydrogenase from 13 normal controls and 78 G6PD-deficient patients from the GDR and other socialist countries has been investigated by multivariate statistical methods. Using principal component analysis a two-dimensional presentation of the data was obtained from which similarities between individual enzyme variants became detectable. Conclusions could be drawn in how as far the kinetic parameters contribute to the discrimination between different variants. An objective classification of G6PD-variants was achieved by application of cluster analysis. The proposed methods provide an effective means for differential elucidation of G6PD-enzymopathies and should be also useful in the case of other enzymopathies.

Cluster Analysis↗
PubMed1999

Histological type and syncytial growth pattern affect E-cadherin expression in a multifactorial analysis of a combined panel of sporadic and BRCA1-associated breast cancers.

E-cadherin is a prominent factor in maintaining the epithelial architecture, and loss of its normal function is considered to be a key element in cancer invasion. In breast cancer, correlation between alteration of E-cadherin expression and histological type has been reported, but associations with other parameters remain uncertain. To refine these findings and to explore the biological significance of features thought to result from alterations of cell-to-cell adhesion systems, rare in sporadic cases but more frequent in BRCA1-associated breast cancers (BRCA1-BCs), we investigated E-cadherin expression by immuno-histochemistry in a combined panel of 214 breast cancers enriched in hereditary cases (176 sporadic cases and 38 BRCA1-BCs). Following multivariate statistical analysis using a logistic regression model, only 2 parameters were significantly associated with loss of E-cadherin expression: lobular histological type (p < 0.0001), in agreement with previous results, and syncytial growth pattern (SGP) (p = 0.01). The latter result provides a biological basis for SGP, the cardinal feature of medullary breast carcinoma.

BRCA1 Protein↗
PubMed1995

Lung tumor cells: a multivariate approach to cell classification using two-dimensional protein pattern.

High resolution two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) is a powerful research tool for the analytical separation of cellular proteins. The qualitative and quantitative pattern of polypeptides synthesized by a cell represents its phenotype and thus defines characteristics such as the morphology and the biological behavior of the cell. By analyzing and comparing the protein patterns of different cells it is possible to recognize the cell type and also to identify the most typical features of these cells. In applied pathology it is often difficult to identify the tissue of origin and the stage or grade of a neoplasia by cellular morphology analyzed by classical or immunostaining procedures. The protein pattern itself is the most characteristic feature of a cell and should therefore contribute to the identification of the cell type. For this reason we separated protein fractions originating from different lung tumor cell lines using 2-D PAGE and we compared the resulting patterns on a multivariate statistical level using correspondence analysis (CA) and ascendant hierarchical clustering (AHC). The results indicate that (i) protein patterns are highly typical for cells and that (ii) the comparison of the protein patterns of a set of interesting cell types allows the identification of potentially new marker proteins. 2-D PAGE is thus a unique and powerful tool for molecular cytology or histopathology, unveiling the protein expression level of tissues or cells.

Adenocarcinoma↗
PubMedDate not supplied

Automated production support for the bioprocess industry.

This paper describes the application of Artificial Intelligence and Multivariate Statistical Techniques to two industrial fermentation systems. In the first example, an Expert System is shown to provide tighter control of an important process parameter. This is shown to lead to improved consistency of operation. In the second application, Principal Component Analysis is applied to a final stage fermentation production facility. The results presented indicate that the algorithm can provide concise indicators of process faults that can be presented to the operators to assist them in taking suitable corrective actions.

Algorithms↗
PubMed1997

Motor patterns and kinematics during backward walking in the pacific giant salamander: evidence for novel motor output.

Kinematic and motor patterns during forward and backward walking in the salamander Dicamptodon tenebrosus were compared to determine whether the differences seen in mammals also apply to a lower vertebrate with sprawling posture and to measure the flexibility of motor output by tetrapod central pattern generators. During treadmill locomotion, electromyograms (EMGs) were recorded from hindlimb muscles of Dicamptodon while simultaneous high-speed video records documented movement of the body, thigh, and crus and allowed EMGs to be synchronized to limb movements. In forward locomotion, the trunk was lifted above the treadmill surface. The pelvic girdle and trunk underwent smooth side-to-side oscillations throughout the stride. At the beginning of the stance phase, the femur was protracted and the knee joint extended. The knee joint initially flexed in early stance and then extended as the foot pushed off in late stance, reaching maximum extension just before foot lift-off. The femur retracted steadily throughout the stance. In the swing phase, the femur rapidly protracted, and the leg was brought forward in an "overhand crawl" motion. In backward walking, the body frequently remained in contact with the treadmill surface. The pelvic girdle, trunk, and femur remained relatively still during stance phase, and most motion occurred at the knee joint. The knee joint extended throughout most of stance, as the body moved back, away from the stationary foot. The knee flexed during swing. Four of five angles showed significantly smaller ranges in backward than in forward walking. EMGs of forward walking showed that ventral muscles were coactive, beginning activity just before foot touchdown and ceasing during the middle of stance phase. Dorsal muscles were active primarily during swing. Backward locomotion showed a different pattern; all muscles except one showed primary activity during the swing phase. This pattern of muscle synergy in backward walking never was seen in forward locomotion. Also, several muscles demonstrated lower burst rectified integrated areas (RIA) or durations during backward locomotion. Multivariate statistical analysis of EMG onset and RIA completely separated forward and backward walking along the first principal component, based on higher RIAs, longer durations of muscle activity, and greater synergy between ventral muscles during early stance in forward walking. Backward walking in Dicamptodon uses a novel motor pattern not seen during forward walking in salamanders or during any other locomotor activity in previously studied tetrapods. The central neuronal mechanisms mediating locomotion in this primitive tetrapod are thus capable of considerable plasticity.

Analysis of Variance↗
PubMed2004

(1H) MRS studies of signals from mobile lipids and from lipid metabolites: comparison of the behavior in cultured tumor cells and in spheroids.

(1)H magnetic resonance studies on MCF-7 and HeLa cells were undertaken to reveal differences in lipid and lipid metabolite signals during the growth in culture. High intensity mobile lipid (ML) signals were found during the first days in culture, while afterwards the same signals declined and started increasing again at confluence and at late confluence. At the same time, signals from the lipid metabolite phosphocholine decreased in intensity while signals from glycerophosphocholine in MCF-7 and from choline in HeLa increased as cells approached confluence. Spectral parameters from actively proliferating and non-proliferating cells were used to classify cells with respect to the proliferative conditions by means of a multivariate statistical analysis. Furthermore, it was shown that polyunsaturation of mobile lipid chains was lower in the confluent group with respect to the actively proliferating cells. The examination of spectra from suspensions of MCF-7 spheroids with diameter smaller than 500 microm suggests that cells in spheroids are in condition of lipid metabolism similar to that of confluent cultured cells.

Algorithms↗
PubMed2006

Patient, implant, and alignment factors associated with revision of medial compartment unicondylar arthroplasty.

The investigators reviewed 245 fixed-bearing unicondylar arthroplasties that one surgeon performed as treatment of medial compartment osteoarthritis between 1988 and 1997 using a variety of cemented metal-backed tibial components and gamma-irradiated-in-air polyethylene bearings. Multivariate statistical analysis was used to evaluate how the event of revision was influenced by 3 patient factors, 3 implant factors, and 7 factors assessed from preoperative and early postoperative radiographs. Five factors were statistically associated with revision: (younger) patient age, (thinner) tibial component initial thickness, (longer) polyethylene shelf age, (lesser) angular reduction of medial tibial plateau varus, and (more varus) postoperative hip-knee-ankle angle. Besides illustrating deleterious consequences of using gamma-irradiated-in-air polyethylene in medial unicompartmental arthroplasty, our results support reducing varus angulation of the medial tibial plateau and knee at surgery.

Age Factors↗
PubMed2002

Analyzing the physiological signature of anabolic steroids in cattle urine using pyrolysis/metastable atom bombardment mass spectrometry and pattern recognition.

Pyrolysis coupled to metastable atom bombardment (MAB) and time-of-flight mass spectrometry (TOFMS) is used for generating mass spectra from bovine urine samples obtained from cattle treated with anabolic steroids. These spectra constitute fingerprints, which can be discriminated by multivariate statistical analysis. Four main conclusions can be drawn from this work: (i) The use of different metastable gases, such as Xe*, Kr*, or N2*, as an energy-tunable ionization beamline allows control of the internal energy and the dissociation processes of the produced odd electron molecular ions, thus giving rise to complementary mass spectra fingerprints. (ii) A variable transformation depending on the biofluid matrix suitably contracts the frequency distribution of the generated data for low m/z ratios holding information related to endogenous metabolites encountered in urine. (iii) Coupling variable selection to statistical pattern recognition methods results in low error rates (< 1%) for predicting MAB mass fingerprints, especially using lineardiscriminant analysis (LDA). (iv) LDA discriminates controls from treated animals and also correlates to quantitative physiological responses induced by anabolic steroids. This work shows that Py-MAB-TOFMS could be a suitable method for complementary monitoring anabolic use in sports, medicine, and cattle breeding, as well as monitoring many other long-lasting although weak physiological disruptions.

Anabolic Agents↗