Adsorption of etioporphyrin and Ni-etioporphyrin on a fractal silica

2001 ◽  
Vol 79 (5-6) ◽  
pp. 817-822 ◽  
Author(s):  
Josephine Mary Hill ◽  
Flora TT Ng
Keyword(s):  
Fractal Dimension ◽  
Heavy Oil ◽  
Fractal Geometry ◽  
Effective Size ◽  
Cross Sectional ◽  
Metal Compounds ◽  
X Ray ◽  
The Relationship ◽  
Ray Methods ◽  
Monolayer Coverage

Metal compounds are contaminants in heavy oil and must be removed using hydrodemetallization catalysts. To optimize the structure of hydrodemetallization catalysts it is useful to know the effective size of the metal compounds. To this end, fractal geometry has been used to determine the relationship between monolayer coverage and adsorbate size for silica by adsorbing a series of alcohols at 298 K. It was found that the silica had a fractal dimension of 2.923. Etioporphyrin and Ni-etioporphyrin were then adsorbed on the silica and their effective areas determined based on this fractal dimension. Cross-sectional areas of 4.58 and 14.8 nm2 were determined for etioporphyrin and Ni-etioporphyrin, respectively. The areas are larger than those determined by X-ray methods and likely reflect the fact that the porphyrins are solvated with solvent (cyclohexane) molecules.

scholarly journals Diurnal Salivary Cortisol in Sarcopenic Postmenopausal Women: The OsteoLaus Cohort

2021 ◽  
Author(s):  
Elena Gonzalez Rodriguez ◽  
Pedro Marques-Vidal ◽  
Bérengère Aubry-Rozier ◽  
Georgios Papadakis ◽  
Martin Preisig ◽  
...  
Keyword(s):  
Postmenopausal Women ◽  
Salivary Cortisol ◽  
Population Based ◽  
Cross Sectional Study ◽  
Body Composition Assessment ◽  
Cross Sectional ◽  
X Ray ◽  
Free Cortisol ◽  
Cortisol Levels ◽  
The Relationship

AbstractSarcopenia, similar to hypercortisolism, is characterized by loss of muscle mass and strength. Cortisol circadian rhythm changes with aging (blunted late-day nadir values) were suggested to contribute to this decline. We aimed to explore the relationship between diurnal salivary cortisol values and sarcopenia diagnosis and its components in postmenopausal women. This is a cross-sectional study within the OsteoLaus population-based cohort in Lausanne (Switzerland). Participants had a body composition assessment by dual X-ray absorptiometry (DXA), a grip strength (GS) measure, and salivary cortisol measures (at awakening, 30 min thereafter, 11 AM (sc-11AM) and 8 PM (sc-8PM)). Associations between salivary cortisol and sarcopenia diagnosed by six different criteria (based on appendicular lean mass (ALM) assessed by DXA, and muscle strength by GS), and its components, were analyzed. 471 women aged > 50 years (63.0 ± 7.5) were included. Various definitions identified different participants as sarcopenic, who consistently presented higher salivary cortisol at 11 AM and/or 8 PM. There were no associations between salivary cortisol levels and ALM measures, either absolute or after correction to height squared (ALM index) or body mass index. GS was inversely correlated to sc-11AM (r = − 0.153, p < 0.001) and sc-8PM (r = − 0.118, p = 0.002). Each 10 nmol/l increase of sc-11AM, respectively sc-8PM, was associated with a GS decrease of 1.758 (SE 0.472) kg, respectively 2.929 (SE 1.115) kg. In postmenopausal women, sarcopenia is associated with higher salivary cortisol levels at 11 AM and 8 PM. An increase of daily free cortisol levels in the physiological range could participate to sarcopenia development by decreasing muscle function in postmenopausal women.

scholarly journals Prevalence of Sarcopenic Obesity Using Different Definitions and the Relationship With Strength and Physical Performance in the Canadian Longitudinal Study of Aging

2021 ◽  
Vol 11 ◽  
Author(s):  
Sarah A. Purcell ◽  
Michelle Mackenzie ◽  
Thiago G. Barbosa-Silva ◽  
Isabelle J. Dionne ◽  
Sunita Ghosh ◽  
...  
Keyword(s):  
Longitudinal Study ◽  
Physical Performance ◽  
Gait Speed ◽  
Walking Speed ◽  
Handgrip Strength ◽  
Sarcopenic Obesity ◽  
Cross Sectional ◽  
X Ray ◽  
The Relationship ◽  
Negative Health Outcomes

Sarcopenic obesity is associated with several negative health outcomes. However, the prevalence of this condition – and the relationship to physical performance parameters – varies across definitions. The aim of this cross-sectional investigation was to describe the prevalence of sarcopenic obesity using different published definitions and their relationship with handgrip strength and walking speed in older Canadian adults. Individuals aged 65+ in the Canadian Longitudinal Study on Aging (n = 11,803; 49.6% male, 50.4% female) were included. Body composition was measured using dual X-ray absorptiometry. Sarcopenic obesity was defined using 29 definitions. Low handgrip strength was identified as &lt; 27 kg in males and &lt; 16 kg in females and poor physical performance was defined as gait speed ≤ 0.8 m/s. The prevalence of sarcopenic obesity ranged from 0.1 to 85.3% in males, and from 0 to 80.4% in females. Sarcopenic obesity was frequently associated with low handgrip strength (p &lt; 0.05) in both males (14/17 definitions, 82.4%) and females (21/29 definitions, 72.4%). In very few definitions, sarcopenic obesity was associated with slow gait speed (males: 1/17 definitions [6.7%]; females: 2/29 [6.9%]). In conclusion, the prevalence of sarcopenic obesity varied greatly according to definitions and sarcopenic obesity was frequently associated with low handgrip strength.

scholarly journals A Fractal and Numerical Simulation Coupled Study of Fracture Network during Coal Mining Excavation

2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
Yanan Gao ◽  
Feng Gao ◽  
Man-chu Ronald Yeung
Keyword(s):  
Fractal Dimension ◽  
Fractal Geometry ◽  
Numerical Study ◽  
Fracture Network ◽  
Mining Engineering ◽  
Deformation Method ◽  
Discontinuous Deformation ◽  
Relationship Of ◽  
The Relationship ◽  
Rock Strata

This paper features a numerical study that is carried out by using discontinuous deformation method (DDA) and fractal geometry. The configurations of rock strata calculated by DDA were imported into a code that is written by using VC++ called “Fractal” to calculate the fractal dimension of the rock strata. As illustrated, a long wall mining case in China was presented. The relationship of the fractal dimension, excavation length, stress, and movement of strata were discussed. The evolution of fractal dimension can be considered as an index of instability or failure. The method proposed in this paper can be employed to predict the period weighting in long wall mining engineering.

Abstract 321: Central Blood Pressure Regulation in Relation to Hypertension and Adiposity in Youth

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Neil E Hultgren ◽  
Nicholas G Evanoff ◽  
Alexander M Kaizer ◽  
Kyle D Rudser ◽  
Donald R Dengel ◽  
...  
Keyword(s):  
Body Fat ◽  
Regression Models ◽  
Linear Regression Models ◽  
Hypertension Status ◽  
Cross Sectional ◽  
X Ray ◽  
Post Hoc ◽  
Sectional Analysis ◽  
The Relationship ◽  
Pearson Correlations

Introduction: The relationship between different central BP measurements with hypertension status in youth is not well documented. We hypothesized that measures of central BP would be positively associated with hypertension status in youth independent of adiposity. Methods: We recruited 149 males and 160 females for this cross-sectional analysis (mean±SD: age = 12.8±2.7; BMI percentile (%) = 78.5±27.8). Body fat % was measured by dual energy X-ray absorptiometry (DXA) and brachial BP was measured using an automated cuff to calculate systolic BP (SBP) and diastolic BP (DBP). Determined by systolic percentile, there were 238 normotensive (<90 th ), 29 pre-hypertensive (<90 th - <95 th ), and 42 hypertensive (<95 th ) individuals enrolled. Central BP was determined using the SphygmoCor MM3 system to calculate carotid-aorta SBP (caSBP) carotid-aorta DBP (caDBP) radial-aorta SBP (raSBP) and radial-aorta DBP (raDBP). Central BP measures were compared across hypertension status groups using ANCOVA, with post-hoc Tukey HSD, adjusted for age, sex, and race. Pearson correlations (unadjusted) and multiple linear regression models, examining the relationship between central BP measures with brachial BP adjusted for age, sex, race, and height, were conducted with further adjustment for body fat % (shown as β±SE). Results: raSBP, caSBP, raDBP, and caDBP were significantly different between the normotensive and hypertensive groups (all p<0.001). No statistically significant differences were found between normotensive and pre-hypertensive or between pre-hypertensive and hypertensive groups. raSBP and caSBP were correlated to SBP (r=0.59, r=0.62, respectively, p<0.001). raDBP and caDBP were correlated to DBP (r=0.58, r=0.6, respectively, p<0.001). In regression analysis, SBP was positively associated with both raSBP and caSBP (β=0.3±0.06, p<0.001) and (β=0.28±0.08, p<0.001), respectively. DBP was positively associated with raDBP and caDBP (β=0.31±0.06, p<0.001) and (β=0.31 ±0.06, p<0.001), respectively. All associations remained significant after adjustment for body fat %. Conclusion: These data suggest that central BP, regardless of measurement site, is highly associated with brachial BP and hypertension status in youth independent of adiposity.

scholarly journals The Fractal Dimension of X-Ray Tomographic Sections of a Woven Composite

2004 ◽  
Vol 13 (2) ◽  
pp. 096369350401300 ◽  
Author(s):  
John Summerscales ◽  
Paul M Russell ◽  
Stepan Lomov ◽  
Ignaas Verpoest ◽  
Richard S Parnas
Keyword(s):  
Fractal Dimension ◽  
Fractal Dimensions ◽  
Woven Composite ◽  
Cross Sectional ◽  
Data Set ◽  
X Ray ◽  
Dimension Analysis ◽  
Glass Fibre Reinforced ◽  
Fractal Dimension Analysis ◽  
X Ray Computed

Plain woven E-glass fibre-reinforced epoxy resin composites have been imaged using X-ray computed tomography. A data-set of 150 cross-sectional slices have been quantified using fractal dimensions. For this data set, the fractal dimension analysis returns a consistent numerical value for each of the slices in the two similar orthogonal planes.

X-ray studies on pyrolusite (including polianite) and psilomelane

1937 ◽  
Vol 24 (157) ◽  
pp. 521-526 ◽  
Author(s):  
George Vaux
Keyword(s):  
Polarized Light ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Relationship ◽  
Ray Methods

One of the most promising uses of X-ray diffraction methods in mineralogy is the study of those minerals which are opaque and whose crystals are extremely minute. Although recent methods of ore examination by reflected polarized light have given valuable information about these substances, their application to soft, powdery materials is extremely difficult, an objection which does not apply to X-ray methods.Pyrolusite (including polianite).—The present study had for its main objective an attempt to settle, by X-ray examination , the uncertainty existing as to the relationship between polianite and pyrolusite, Work already carried out by St. Johns has suggested that polianite and pyrolusite are identical, since they have the same cell sides as found from powder photographs.

scholarly journals Associations of Body Mass Index With Incident Fractures and Hip Structural Parameters in a Large Canadian Cohort

2016 ◽  
Vol 101 (2) ◽  
pp. 476-484 ◽  
Author(s):  
Jian Shen ◽  
William D. Leslie ◽  
Carrie M. Nielson ◽  
Sumit R. Majumdar ◽  
Suzanne N. Morin ◽  
...  
Keyword(s):  
Body Mass Index ◽  
Hip Fracture ◽  
Lower Risk ◽  
Structural Parameters ◽  
Dual Energy ◽  
Sectional Area ◽  
Strength Index ◽  
Cross Sectional ◽  
X Ray ◽  
The Relationship

Abstract Context: Fractures in obese individuals are of public health importance, but the relationship between obesity and fracture is complex and remains poorly understood. Objective: The study examined the association of body mass index (BMI) with bone structural and strength parameters and incident fracture. Design and Setting: We performed cross-sectional and longitudinal analyses using data from the Manitoba Bone Density Program. Participants: We included 51 313 women and 4689 men aged 50 years or older referred for dual-energy X-ray absorptiometry scans. For 41 919 women and 4085 men, we were able to derive hip structural parameters. Main Outcome Measure: Cross-sectional moment of inertia, cross-sectional area, and femoral strength index were derived from dual-energy X-ray absorptiometry. Health service records were assessed for incident major osteoporotic fractures (MOFs) (mean follow-up 6.2 y in women and 4.7 y in men). Results: Among individuals with a BMI of less than 30 kg/m2, increasing BMI was associated with progressive increases in bone mineral density (BMD), cross-sectional moment of inertia, and cross-sectional area. The relationship reached a plateau around a BMI of 30 kg/m2, with little additional increment with further increases in BMI (all P for interaction &lt; .0001, obese vs nonobese). Increasing BMI was linearly associated with decreases in strength index in both women and men. MOFs were ascertained in 3721 women and 276 men (1027 female and 75 male hip fractures). Higher BMI was associated with a lower risk of MOF in women in multivariable models, but this association was largely explained by their higher BMD. Protective association of higher BMI with hip fracture were stronger and only partially explained by BMD (hazard ratio [95% confidence interval] 0.79 [0.73–0.99] for obese I and 0.67 [0.46–0.98] for obese II). Higher BMI was not significantly associated with a risk of MOF or hip fracture in men. Conclusions: Despite structural and biomechanical disadvantages, obese women were at lower risk of fracture.

scholarly journals Application of Fractal Geometry to Study the Geological Structure of the Zarin Plain (Plain Razak)

2014 ◽  
Vol 3 (11) ◽  
pp. 135-144
Author(s):  
Khadijeh Faridi Nia ◽  
Asghar Teymoorian ◽  
Mojtaba Babaei
Keyword(s):  
Fractal Dimension ◽  
Density Dependence ◽  
Fractal Geometry ◽  
Bouguer Anomaly ◽  
Geological Structure ◽  
Optimal Density ◽  
The Relationship ◽  
Rigid Shell

One of the most important steps to obtain the specified density Bouguer anomaly corrections for the topography of the page Bouguer is the most commonly used way in which the relationship between topography and Bouguer anomaly in the method assumes that topography of the rigid shell instead Isoztasi balance is maintained. The method to determine the density of Bouguer provided by fractal analyze these are the lowest density dependence the topography of the area is considered as the optimal density and the fractal relationship to the topography of the fractal dimension using the Bouguer anomaly.

scholarly journals HUBUNGAN GAMBARAN FOTO TORAKS DAN UJI TUBERKULIN PADA ANAK DENGAN DIAGNOSIS TUBERKULOSIS PARU DI RSUP PROF. DR. R. D. KANDOU MANADO PERIODE JANUARI 2012 – DESEMBER 2012

e-CliniC ◽  
2014 ◽  
Vol 2 (1) ◽  
Author(s):  
Alfa G. A. Poluan
Keyword(s):  
Pulmonary Tuberculosis ◽  
Tuberculin Test ◽  
Cross Sectional ◽  
X Ray ◽  
Chest X Ray ◽  
Cross Sectional Design ◽  
Tuberculosis In Children ◽  
The Relationship ◽  
Global Health Problem ◽  
Research Analysis

Abstrak: Tuberkulosis (TB) masih menjadi masalah kesehatan dunia yang utama sampai sekarang. Menurut WHO, Indonesia masih menjadi negara dengan peringkat keempat sebagai penyumbang TB terbesar dengan 400-500 ribu kasus. WHO melaporkan bahwa ada sekitar 327.000 kasus baru TB pada anak dengan usia <15 tahun di seluruh dunia, dan sekitar 65.000 anak meninggal karena TB setiap tahun. Dalam mendiagnosis TB anak perlu dilakukan pemeriksaan uji tuberkulin dan foto toraks. Tujuan penelitian ini adalah untuk mengetahui hubungan gambaran foto toraks dan uji tuberkulin pada anak dengan diagnosis tuberkulosis paru.  Penelitian ini dilakukan di RSUP Prof. Dr. R. D. Kandou Manado periode Januari 2012 – Desember 2012. Penelitian ini bersifat analitik observasional menggunakan desain cross sectional dengan data retrospektif. Pengambilan sampel pada penelitian ini menggunakan teknik total sampling. Data yang dikumpulkan diolah dengan menggunakan uji korelasi Kendall’s tau-b. Dari hasil analisa data didapatkan nilai r= -0,408 dengan p= 0,046 (p<0,05). Nilai ini berarti bahwa ada hubungan negatif sedang antara gambaran foto toraks dan uji tuberkulin. Dengan demikian, pemeriksaan foto toraks dan uji tuberkulin harus dilakukan dalam membantu menegakkan diagnosis tuberkulosis paru pada anak. Kata kunci: Foto toraks, uji tuberkulin, tuberkulosis paru, anak    Abstract: Tuberculosis (TB) remains a major global health problem until now. According to WHO, Indonesia has ranked as the fourth largest contributor TB with 400-500 cases. WHO reports that there are approximately 327,000 new cases of TB in children aged <15 years old all over the world, and about 65,000 children die from TB every year. In diagnosing TB in children, tuberculin test and chest x-ray are necessary. The purpose of this research is to determine the relationship between a chest x-ray picture and tuberculin test in children diagnosed with pulmonary tuberculosis. This research was conducted in RSUP Prof. Dr. R. D. Kandou Manado in the period of January 2012 – December 2012. This was an observational analytic research using cross-sectional design with retrospective data. There were 25 children observed in this research. Analysis shows a negative correlation between radiographic picture and tuberculin test (r= -0.408; p= 0.046). Accordingly, chest x-ray examination and tuberculin test should be performed to help justify the diagnosis of pulmonary tuberculosis in children. Key Words: Chest X-ray, Tuberculin test, Pulmonary Tuberculosis, Children

scholarly journals Consistency of fat mass–fat-free mass relationship across ethnicity and sex groups

2010 ◽  
Vol 105 (8) ◽  
pp. 1272-1276 ◽  
Author(s):  
Stephanie T. Broyles ◽  
Claude Bouchard ◽  
George A. Bray ◽  
Frank L. Greenway ◽  
William D. Johnson ◽  
...  
Keyword(s):  
African American ◽  
Fat Mass ◽  
African American Men ◽  
Small Sample ◽  
Fat Free Mass ◽  
Linear Regression Models ◽  
Cross Sectional ◽  
Men And Women ◽  
X Ray ◽  
The Relationship

The model developed by Forbes (1987) of how body fat mass (FM) and fat-free mass (FFM) change during periods of weight loss or gain (Δ body weight (BW)) assumed that they change in relationship to a constantC = 10·4, where ΔFFM/ΔBW = 10·4/(10·4+FM). Forbes derivedCbased on aggregated, cross-sectional data from a small sample of women. The objective of the present study was to reanalyse the relationship described by Forbes and to explore whether this relationship is consistent across ethnicity and sex groups using cross-sectional data from a large sample of white and African-American men and women. Baseline data from white and African-American men and women aged 18–60 years, who participated in a clinical study at the Pennington Biomedical Research Center since 2001 and who underwent dual-energy X-ray absorptiometry scans, were available for analysis. To overcome differences in BMI distributions among the ethnicity-by-sex groups, a stratified random sample of participants was selected within each group such that numbers in each BMI category ( < 25, 25–29·9, 30–34·9, 35–39·9, 40+ kg/m2) were proportional to those within the group with the smallest sample size, yielding a sample of 1953 individuals. Linear regression models assessed the FM–FFM relationship across the four ethnicity-by-sex groups. The FM–FFM relationship varied little by ethnicity (P = 0·57) or by sex (P = 0·26). The constant describing the FM–FFM relationship was estimated to be 9·7 (95 % CI 9·0, 10·3). In conclusion, results from our large, biethnic sample of men and women found a FM–FFM relationship very close to that originally described by Forbes, absent of significant variability by ethnicity or sex.

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