PHYSICOCHEMICAL STUDIES OF ALKALI LIGNINS: II. ULTRACENTRIFUGAL SEDIMENTATION ANALYSIS

1960 ◽  
Vol 38 (2) ◽  
pp. 259-269 ◽  
Author(s):  
P. R. Gupta ◽  
R. F. Robertson ◽  
D. A. I. Goring

Ultracentrifugal sedimentation of alkali lignin fractions revealed marked boundary spreading at low and high centrifugal fields. An analysis of the gradient diagrams indicated a wide distribution of sedimentation coefficients ranging from 0.5 to over 400 × 10−13 second. There was only a small decrease in the polydispersity on subfractionation. The distributions were continuous with a single peak and positive skewness. A linear relationship was found between the intrinsic viscosity and the standard deviation of the weight-average sedimentation coefficient. The sedimentation coefficient based on the movement of the maximum ordinate at a field of 11.5 × 103 g was several times greater than the corresponding coefficient for the same fraction at 200 × 103 g. A qualitative interpretation of this phenomenon is given in terms of the Faxen and the Archibald solution to the Lamm equation.

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Yuntian Chu ◽  
Qianqian Zhao ◽  
Mei Zhang ◽  
Bo Ban ◽  
Hongbing Tao

Abstract Background Elevated triglyceride (TG) levels are a biomarker for cardiovascular disease (CVD) risk. The correlation between serum uric acid (SUA) and TG concentrations in adults or obese children is well established. However, studies on SUA and TG in children with short stature are limited. Aim To determine the relationship between SUA and TG levels in short children and adolescents. Method This was a cross-sectional evaluation of a cohort of 1095 patients with short stature (720 males and 375 females). The related clinical characteristics, including anthropometric and biochemical parameters, were determined. Results Smooth curve fitting, adjusted for potential confounders was performed, which indicated the existence of a non-linear relationship between these measures. Piecewise multivariate linear analysis revealed a significant positive relationship between SUA and TG at SUA concentrations over 7 mg/dL (β = 0.13, 95% CI: 0.05–0.22, P = 0.002) but no significant correlation at lower SUA levels (β = 0.01, 95% CI: 0.01–0.04, P = 0.799). Furthermore, a stratified analysis was performed to appraise changes in this relationship for different sexes and standard deviation levels of body mass index (BMI). The non-linear relationship remained consistent in males and females with BMI standard deviation scores (BMI SDS) ≥ 0, with inflection points of 6.71 mg/dL and 3.93 mg/dL, respectively. Within these two groups, SUA and TG levels showed a positive association when SUA levels were higher than the inflection point (β = 0.21, 95% CI: 0.11–0.31, P < 0.001 for males and β = 0.1, 95% CI: 0.03–0.17, P = 0.005 for females). However, a specific relationship was not observed at lower SUA levels. No significant relationships were found between SUA and TG levels in males and females with BMI SDS < 0. Conclusion The present study identified the non-linear association of SUA and TG levels with short children and adolescents. This relationship was based on BMI status. This finding suggests that health status should be considered for short stature children with high SUA levels, especially in children with a high BMI standard deviation score.


2012 ◽  
Vol 535-537 ◽  
pp. 1337-1340 ◽  
Author(s):  
Chi Yang ◽  
Nai Lin Ren

A new chemiluminescence system was built by using gadolinium as sensitizer, and the analysis capabilities of this system was tested as below. The method is based on chemluminescence of Ce (IV)-SO32- sensitized by Gd3+-OFLX. The effects of some critical experimental conditions were discussed and the optimum conditions for chemluminescence emission were investigated. The linear relationship between the relative chemiluminescence intensity and the concentration of OFLX is in the range of 2×10-9 g/mL~5×10-7 g/mL with a detection limit of 1.0×10-9g/mL .The relative standard deviation is 2.8% (n=11) for a level of 5.0×10-7 g/mL. The method has been applied to the analysis of OFLX in tablets with satisfactory results.


1972 ◽  
Vol 27 (10) ◽  
pp. 1205-1215 ◽  
Author(s):  
Wolfgang Beisenherz

The RNA metabolism in tissue cultures of Nicotiana tabacum has been studied by incorporation of radioactive phosphate. The RNA was extracted by phenol-kresol-hydroxychinon and fractionated by MAK columns. A rapidly labelled RNA fraction was eluted from the MAK column after the rRNA components. Its base ratio differed from the latter in that the AMP content (28,6%) was higher than the GMP content (26,0%). Sedimentation analysis on sucrose gradients showed a sedimentation coefficient of 37 -38s. The life time of the 37-38s RNA fraction in chase experiments was 3,5-4 hours. Differential centrifugation of tissue homogenates revealed that the labelled 37-38s RNA was associated with particles sedimented by low speed centrifugation. No 37-38s RNA could be detected in the ribosomal fraction and the supernatant. During chase experiments label appeared in the rRNA components. It could be excluded by thin layer chromatographic separation of 32P labelled compounds that this label originated from 32P-o-phosphate or labelled organic phosphates except of the rapidly labelled 37-38s RNA. From this it was concluded that the 37-38s RNA is a precursor of the rRNA.


1972 ◽  
Vol 18 (6) ◽  
pp. 805-815 ◽  
Author(s):  
M. Kapoor ◽  
T. M. Tronsgaard

Pyruvate kinase of Neurospora crassa has been purified and some of its properties are reported. The procedure used for purification consists of five steps yielding a 90 to 95% purified protein. Preliminary sedimentation analysis yielded a sedimentation coefficient of 9.5 for this enzyme. Maximal stabilization of the enzyme is achieved in phosphate buffer; Tris buffer induces a conformational change in the enzyme leading to inactivation. Inactivation can be reversed by incubation with substrates, PEP and ADP. Preliminary kinetics studies suggest the formation of a ternary complex rather than a Ping Pong type of a mechanism.


Iproceedings ◽  
10.2196/15203 ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. e15203
Author(s):  
Nicole Polanco ◽  
Sharon Odametey ◽  
Neda Derakhshani ◽  
Mark Khachaturian ◽  
Connor Devoe ◽  
...  

Background Wellness devices for health tracking have gained popularity in recent years. Additionally, portable and readily accessible wellness devices have several advantages when compared to traditional medical devices found in clinical environments. Building tools for patients to manage their health independently may benefit their health in the long run by improving health care providers’ (HCPs) awareness of their patients’ health information outside of the clinic. Increased access to portable wellness devices that track vital signs may increase how patients and HCPs track and monitor chronic conditions which can improve health outcomes. The VitalWellness is a portable wellness device that can potentially aid vital sign measuring for those interested in tracking their health. Objective In this diagnostic accuracy study, we evaluated the clinical performance of the VitalWellness, a wireless, compact, non-invasive device that measures four vital signs using the index finger and forehead against reference vital signs devices used in the hospital setting. Methods Volunteers age ≥18 years were enrolled to provide blood pressure (BP), heart rate (HR), respiratory rate (RR), and body temperature. We recruited volunteers with vital signs that fell within and outside of the normal physiological range, depending on the measurements they consented to undergo. A subgroup of eligible volunteers were asked to undergo an exercise test, aerobic step test and/or a paced breathing test to analyze the VitalWellness device's performance on vital signs outside of the normal physiological ranges for HR and RR. Vital signs measurements were collected with the VitalWellness device and FDA-approved reference devices. Mean, standard deviation, mean difference, standard deviation of difference, standard error of mean difference, and correlation coefficients were calculated for measurements collected; these measurements were plotted on a scatter plot and a Bland-Altman plot. Sensitivity analyses were performed to evaluate the performance of the VitalWellness device by gender, skin color, finger size, and in the presence of artifacts. Results We enrolled 265 volunteers in the study and 2 withdrew before study completion. The majority of volunteers were female (62%), predominately white (63%), graduated from college or post college (67%), and employed (59%). There was a moderately strong linear relationship between VitalWellness BP and reference BP (r=0.7, P<.05) and bewteen VitalWellness RR and reference RR measurements (r=0.7, P<.05). The VitalWellness HR readings were significantly in line with the reference HR readings (r=0.9, P<.05). There was a weaker linear relationship between VitalWellness temperature and reference temperature (r=0.3, P<.05). There were no differences in performance of the VitalWellness device by gender, skin color or in the presence of artifacts. Finger size was associated with differential performance for RR. Conclusions Overall, the VitalWellness device performed well in taking BP, HR and RR when compared to FDA-approved reference devices and has potential serve as a wellness device. To test adaptability and acceptability, future research may evaluate user’s interactions and experiences with the VitalWellness device at home. In addition, the next phase of the study will evaluate transmitting vital sign information from the VitalWellness device to an online secured database where information can be shared with HCPs within seconds of measurement.


1978 ◽  
Vol 24 (6) ◽  
pp. 857-861 ◽  
Author(s):  
P J Cornbleet ◽  
M C Shea

Abstract We have studied the effects of range and distribution of data on product moment and rank correlation coefficients when deviation from a linear relationship was due solely to experimentally produced random error. All correlation coefficients (Pearson r, Spearman rho, and Kendall tau) were markedly influenced by the range of the data, and, for the rank correlation coefficients, the effect of range varied for different data distributions. While correlation coefficients may be useful in assessing whether an association exists between two variables, they are not useful in assessing the degree of random error about the regression line when a strong linear association is presumed to exist between the two variables. Thus, neither product moment nor rank correlation coefficients are of value in analysis of laboraoty method-comparison data. The standard deviation of the residual error of regression should be calculated as a measure of the random error about the regression line.


2013 ◽  
Vol 57 (9) ◽  
pp. 4581-4583 ◽  
Author(s):  
Siow-Chin Heng ◽  
Gregory I. Snell ◽  
Bronwyn Levvey ◽  
Dominic Keating ◽  
Glen P. Westall ◽  
...  

ABSTRACTTrough (predose) voriconazole concentrations in plasma and pulmonary epithelial lining fluid (ELF) of lung transplant recipients receiving oral voriconazole preemptive treatment were determined. The mean (± standard deviation [SD]) ELF/plasma ratio was 12.5 ± 6.3. A strong positive linear relationship was noted between trough plasma and ELF voriconazole concentrations (r2= 0.87), suggesting the feasibility of using trough plasma voriconazole concentration as a surrogate to estimate the corresponding concentration in ELF of lung transplant recipients.


1974 ◽  
Vol 140 (3) ◽  
pp. 495-502 ◽  
Author(s):  
Wilma M. O. Van Beurden-Lamers ◽  
Albert O. Brinkmann ◽  
Eppo Mulder ◽  
Henk J. Van Der Molen

The specificity of the binding of oestradiol-17β by cytoplasmic fractions of several tissues of the male rat was investigated. 1. Agar-gel electrophoresis, Sephadex chromatography, adsorption by dextran-coated charcoal and sucrose-gradient centrifugation were used to estimate the binding capacity and specificity. The four different methods all gave similar results for the capacity of the specific oestradiol-17β-binding macromolecules in the testis. 2. The presence of a specific saturable binding protein with a sedimentation coefficient of 8S was demonstrated in liver, adrenal, pituitary, prostate, epididymis and testis interstitial tissue. The highest concentration of oestradiol-17β-binding macromolecules was found in testis interstitial tissue (0.12pmol/mg of protein) and in the pituitary (0.075pmol/mg of protein). 3. The oestradiol-17β receptor in the testis cytosol showed the characteristics of a protein with respect to Pronase treatment and temperature sensitivity. In competition experiments with different steroids the receptor showed a high affinity for oestradiol-17β, a moderate affinity for diethylstilboestrol and oestradiol-17α and a low affinity for oestrone, oestriol, testosterone and 5α-dihydrotestosterone (17β-hydroxy-5α-androstan-3-one). 4. The wide distribution of oestradiol-17β receptors in the male rat is in apparent contradiction to the current concept of the specificity of steroid-hormone action. Further research is required to investigate a possible physiological meaning of the presence of specific receptors in the different tissues.


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