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S S Guo

Publications and source records attributed to S S Guo.

At least 37 records · Page 2Linked to original sources
PubMed2001

[Principle demonstration of nutrient delivery system in a space vegetable planting prototype facility].

Objective. To develop a nutrient delivery system for space vegetable planting prototype facility to be used in future space station, and to preliminarily testify its feasibility through ground-based demonstration experiments. Method. A nutrient delivery system in a space vegetable planting prototype facility was designed and fabricated, and ground based demonstration experiments of plant cultivation were conducted. Result. Nutrient could be steadily delivered to plant cultivation matrixes through capillary action, water content of planting matrixes could be controlled automatically and maintained constant, and the planted material lettuce showed basically normal morphology and color. Conclusion. The nutrient delivery system in a space vegetable planting prototype facility could basically meet the requirements for plant nutrient delivery under space microgravity environmental condition.

Capillary Action↗
PubMed2000

CDC growth charts: United States.

OBJECTIVES: This report presents the revised growth charts for the United States. It summarizes the history of the 1977 National Center for Health Statistics (NCHS) growth charts, reasons for the revision, data sources and statistical procedures used, and major features of the revised charts. METHODS: Data from five national health examination surveys collected from 1963 to 1994 and five supplementary data sources were combined to establish an analytic growth chart data set. A variety of statistical procedures were used to produce smoothed percentile curves for infants (from birth to 36 months) and older children (from 2 to 20 years), using a two-stage approach. Initial curve smoothing for selected major percentiles was accomplished with various parametric and nonparametric procedures. In the second stage, a normalization procedure was used to generate z-scores that closely match the smoothed percentile curves. RESULTS: The 14 NCHS growth charts were revised and new body mass index-for-age (BMI-for-age) charts were created for boys and girls (http://www.cdc.gov/growthcharts). The growth percentile curves for infants and children are based primarily on national survey data. Use of national data ensures a smooth transition from the charts for infants to those for older children. These data better represent the racial/ethnic diversity and the size and growth patterns of combined breast- and formula-fed infants in the United States. New features include addition of the 3rd and 97th percentiles for all charts and extension of all charts for children and adolescents to age 20 years. CONCLUSION: Created with improved data and statistical curve smoothing procedures, the United States growth charts represent an enhanced instrument to evaluate the size and growth of infants and children.

Adolescent↗
PubMed2000

[Allelic polymorphism of HLA-DQA1 locus in Han nationality in Hunan province].

OBJECTIVE: To explore the genetic polymorphism of HLA-DQA1 locus in Han nationality in Hunan province. METHOD: Sixty samples randomly selected from healthy individuals of Han nationality in Hunan province were typed for HLA-DQA1 by PCR/SSP in combination with silver-staining PCR/SSCP. RESULTS: Ten types of HLA-DQA1 alleles were found in all 60 samples, HLA-DQA1*0302, *0501, *0102 were the common alleles with gene frequencies of 0.2254, 0.2254, and 0.2041 respectively. Twenty-six kinds of genotypes were found, and the genotype distribution fitted the Hardy-Weinberg equilibrium test (P > 0.05). Five samples which had ambiguity in their PCR/SSP typing were further clarified with PCR/SSCP analysis. CONCLUSIONS: Normal gene frequency values of HLA-DQA1 alleles in Han nationality in Hunan province are provided; PCR/SSCP can be used to eliminate the ambiguity which might exist in PCR/SSP typing for HLA-DQA1 locus.

Alleles↗
PubMed2000

[Correlative study on HLA-DR2 allelic polymorphism and systemic lupus erythematosus in the Han nationality in Hunan province].

Fifty-eight systemic lupus erythematosus (SLE) patients and 59 normal controls of the Han nationality in Hunan province were involved in this study to analyze the correlation between HLA-DR2 group specific amplification in combination with HLA-DRB generic amplification PCR/SSCP technique to detect the sequence variation within exon 2 of HLA-DR2 alleles outside the sequence specific primer matching positions. The results were that HLA-DR2 was strongly correlated with SLE (RR = 2.71, P < 0.01); and HLA-DRB1 * 1501 was the allele correlated with disease (RR = 3.01, Pc < 0.05). In addition, PCR/SSCP showed that there was not any novel sequence variation in exon 2 of HLA-DR2 alleles in the Han nationality in Hunan province.

Alleles↗
PubMed2000

Lifetime overweight status in relation to serial changes in body composition and risk factors for cardiovascular disease: The Fels Longitudinal Study.

OBJECTIVE: The aims were to determine if 1) individuals who became and maintained overweight during their entire lifetime differ from those who were never-overweight in terms of annual changes in adiposity and concurrent changes in cardiovascular disease (CVD) risk factors; 2) the changes and their relationships to each other varied between these groups or by sex within the groups; and 3) alcohol usage, smoking habits, and level of physical activity differed between groups. RESEARCH METHODS AND PROCEDURES: Data from 16,315 examinations of 414 individuals were utilized to assess lifetime overweight (body mass index [BMI] > 25 kg/m2) status. A regressive analytic approach was used to determine the average annual changes for each individual over an adult serial interval ranging from 4 to 20 years. RESULTS: Men and women who have become and maintained overweight have higher blood pressure and a poorer lipid/lipoprotein risk profile than those who have never been overweight. There is an accelerated deterioration in the atherogenic profile of overweight men and women as indicated by annual changes in CVD risk factors about double that of their never-overweight counterparts. In women, increased risk is derived from increasing systolic and diastolic blood pressure, whereas in men the increased risk comes not only from increasing diastolic blood pressure but also cholesterol, triglycerides, and low-density lipoprotein cholesterol levels and, to a lesser extent, decreasing high-density lipoprotein cholesterol. DISCUSSION: The reduced physical activity observed in the overweight adults may be related to their accumulation of adipose tissue at a rate about double their never-overweight counterparts, and this may be driving the higher rate of increase of CVD risk factors in the overweight groups.

Adolescent↗
PubMed2000

Body mass index during childhood, adolescence and young adulthood in relation to adult overweight and adiposity: the Fels Longitudinal Study.

BACKGROUND: Childhood overweight develops during 'critical periods', but the relationship of body mass index (BMI) patterns during 'critical periods' from childhood into adulthood with subsequent overweight and adiposity has not been previously investigated. BMI patterns during early childhood, pubescence and post-pubescence and their independent effects on overweight and body fatness at 35-45 y of age were examined along with birth weight and the effects of adult lifestyle factors. METHODS: BMI parameters describing the timing, velocity minimum (min) and maximum (max) values from 2 to 25 y of age were related to adulthood BMI values and total and percentage body fat (TBF, %BF) at 35-45 y. These data were from 180 males and 158 females in the Fels Longitudinal Study. RESULTS: There was no sex difference in the timing of BMI rebound, but the age of BMI maximum velocity and maximum BMI were both earlier in girls. Children with an earlier BMI rebound had larger BMI values at rebound and at maximum velocity. Children who reached maximum BMI at later age had larger maximum BMI values. Maximum BMI was a strong predictor for adult BMI and in females, a strong predictor of adulthood TBF and %BF. Maximum BMI was closely related to maximum BMI velocity in females and in males, BMI at maximum velocity is a strong predictor of TBF and %BF. CONCLUSIONS: Changes in childhood BMI were related to adult overweight and adiposity more so in females than males. BMI rebound is a significant important period related to overweight at 35-45 y in females but not in males. However BMI patterns during and post-adolescence were more important than the BMI rebound for adulthood TBF and %BF status. There is marked tracking in BMI from approximately 20 y into 35-45 y. The pattern of BMI changes from 2 to 25 y had stronger effects on subsequent adult overweight than birth weight and adult lifestyle variables.

Adipose Tissue↗
PubMed2000

Epidemiological applications of body composition. The effects and adjustment of measurement errors.

The amounts of fat and fat-free mass (FFM) are functions of lifestyle, diseases, increasing age, and genetics. The levels of these body compartments are established risk factors for cardiovascular and related chronic diseases. Body composition can be assessed by several methods. The measurements for each method have inherent variations, which can be due to error in the measurement or biological variation. This presentation focuses on the reliability and precision of body composition measurements and the impact of these errors on epidemiological and population-based studies. The effects of these errors in applying body composition to epidemiological studies include the following: (1) the association of cardiovascular risk factors with body composition in cross-sectional studies; (2) changes in body composition in longitudinal or intervention studies; (3) association of changes in body composition with cardiovascular risk factors; and (4) comparison of levels of body composition among subgroups in cross-sectional studies and in intervention studies.

Absorptiometry, Photon↗
PubMed2000

Assessment and prevalence of obesity: application of new methods to a major problem.

Overweight and obesity are major health problems worldwide. A body mass index of > or =25 has been classified as overweight and of > or =30 as obesity. However, national and epidemiologic data on overweight and obesity are not based on actual measures of body fat because of the difficulty of collecting such data from large groups and especially from the obese. There are now numerous direct and indirect methods to assess body fat. Anthropometric techniques are the most common indirect methods used in epidemiologic and clinical assessments, but these are restricted in the obese to circumferences. The other methods of assessing body fat are bioelectrical impedance, body density, total body water, and dual X-ray absorptiometry, all of which have advantages and limitations when applied to the obese. All these methods make use of statistical models in calculating body composition. There are several sources of available reference data for anthropometric measures for the US population, but no direct measures of body fat are currently available. There is a clear need for the continued development and validation of new and existing techniques to determine levels of fat.

Absorptiometry, Photon↗
PubMed2000

Childhood weight, stature, and body mass index among never overweight, early-onset overweight, and late-onset overweight groups.

OBJECTIVE: To determine the effects of timing of onset of overweight (OW) on childhood anthropometric adiposity levels using long-term serial data from the Fels Longitudinal Study. CLASSIFICATION: OW was defined as body mass index (BMI; kg/m(2)) >25, and the age at first measurement of BMI >25 was the age of onset of OW. Early onset of OW (early-OW) and late onset of OW (late-OW) were defined as having onset of OW before and after 25 years of age, respectively, whereas never OW (never-OW) was defined as never having a BMI >25. SUBJECTS: Subjects consisted of 67 males and 47 females in early-OW groups, 62 males and 48 females in late-OW groups, and 80 males and 114 females in never-OW groups. RESULTS: Levels of weight and BMI in early-OW males and females were significantly greater than those in never-OW and late-OW males and females beginning at the time of adiposity rebound, which generally occurs between 4 and 8 years of age. Median BMI and weight patterns between never-OW and late-OW males were similar throughout childhood. However, significant differences in median levels of BMI for never-OW and late-OW females began at 11 years of age, although onset of OW was not until >25 years of age in the latter group. CONCLUSIONS: For both males and females, adiposity rebound is likely an effective time in a child's development to detect and initiate prevention for childhood and early adulthood onset of OW. Although later-onset OW needs additional study, puberty seems to be a critical phase in the development of later adult onset of OW in females.

Adult↗
PubMed2000

[Effects of CO2 concentration on growth and development of lettuce in controlled environment].

Objective. To study the tolerance of lettuce to elevated CO2 concentration in Controlled Ecological Life Support System (CELSS). Method. Lettuce was cultivated in the Ground-based Experimental Facility for Higher Plant Cultivation in Space (GEFHPCS), in which many parameters were kept unchanged, while concentration of CO2 was controlled at 5 different levels (2000-10000 micromoles mol-1). During the growing periods, the morphologies of lettuce were observed every day, the replenished amounts of CO2 to GEFHPCS and water to the nutrient fluid box as well as the amounts of condensed water collected from GEFHPCS were all recorded every day. After harvest, the output and photosynthetic rate were calculated and lots of constituents of lettuce were analyzed. Result. The growth of lettuce were relatively ideal when CO2 concentration was at 6000 micromoles mol-1, but an obviously withering appearance was found when CO2 concentration increased 10000 micromoles mol-1, this time the output and quality of lettuce were unsatisfactory. Conclusion. It would be optimal when CO2 concentration is controlled at about 6000 micromoles mol-1 in a lettuce-cultivating chamber.

Biomass↗
PubMed2000

[Development of an experimental facility for waste treatment by microorganism].

Objective. To construct an experimental facility for microorganism waste processing, which will be used to recover plant nutrient liquids from plant inedible biomass essential for growth and development of plants. Method. After technical parameters and performance requirements were defined, plan demonstration, drawing design, fabrication, debug and preliminary plant inedible residue-biodegradation tests of microorganisms were conducted. Result. The temperature, stirring speed and gas-supplying flow of bioreactor of the facility were controlled automatically, as well as the pH and dissolved oxygen concentration were measured automatically and controlled manually, testifying that its performance reached the requirements of predetermined technical indexes. The 15-d test showed that the facility ran smoothly, its above-mentioned parameters could be measured and controlled precisely, and the biodegradation rate of lettuce's inedible biomass approximately attained 90%. Conclusion. The facility holding reasonable technical indexes, smooth and dependable performances, is capable of being utilized to biodegrade plant inedible biomass. It is expected that if the above-mentioned parameter combinations are optimized further, the results should be better.

Biodegradation, Environmental↗
PubMed2000

[Development of a ground-based experimental facility for space cultivation of higher plant].

A ground-based experimental facility was developed for conducting initial ground-based simulation study of Controlled Ecological Life Support System (CELSS). The facility is composed of a main chamber, O2 and CO2 composition control subsystems, plant cultivation subsystem and whole data management subsystem. The growth room, being composed of a inner wall of mirror-face stainless steel, holds a volume of 1.8 m3 and a growing area of 1.2 m2; electronic fluorescent lamps were used as lighting sources and polyvinyl formal was used for root matrixes; the environmental parameters of the growing room such as temperature, relative humidity, O2 concentration, CO2 concentration, lighting period and irradiance intensity and the nutrient parameters such as pH, electrical conductivity, dissolved oxygen concentration, liquid level of nutrient storage tank and flow rate of nutrient were all controlled automatically; all of the above-mentioned parameters can be inspected, collected, stored and printed regularly and dynamically. The results of a combined debugging and preliminary plant cultivation verified that the technical target of the facility had reached its initial design requirements, it can be used to conduct ground-based simulation studies of space cultivation of higher plants.

Air Conditioning↗
PubMed1999

Total body water data for white adults 18 to 64 years of age: the Fels Longitudinal Study.

BACKGROUND: Total body water (TBW) volume is reported to decrease with age, but much of the published data are 20 to almost 50 years old and are cross-sectional. Proper interpretation of clinical levels of TBW and trends with age necessitates the availability of current longitudinal data from healthy individuals. METHODS: Mixed longitudinal data for TBW of 274 white men and 292 white women (18 to 64 years of age) in the Fels Longitudinal Study were collected on a regular schedule over a recent eight-year period. The concentration of deuterium was measured by deuterium nuclear magnetic resonance spectroscopy. Body composition estimates were made with dual-energy x-ray absorptiometry, and random effect models were used to determine the patterns of change over time with and without covariates. RESULTS: The mean TBW data for the Fels men are either similar to or approximately 2 to as much as 6 liters greater than that reported by most other investigators 20 to 50 years ago. For Fels women, the mean TBW ranges from approximately 2 to as much as 5 liters less than that reported previously. These comparisons with much earlier studies reflect cohort effects and the secular changes in overall body size that have occurred during the past 60 to 70 years. These findings are reinforced by the fact that some early data sets included individuals born almost 140 years ago. After adjusting for the covariate effects of total body fat (TBF) and fat-free mass (FFM) with age, there were no significant age or age-squared effects on TBW in the men. In the women, after adjusting for the covariate associations of TBF and FFM with age, there was a small, but significant, negative linear association of TBW with age. In the men and women, the mean ratio of TBW to weight declined with age as a function of an increase in body fatness and more so for the men than the women. CONCLUSION: The findings from these mixed longitudinal data indicate that TBW volume, on average, maintains a reasonable degree of stability in men and women through a large portion of adulthood. These TBW data are recommended as current reference data for healthy adults.

Adipose Tissue↗
PubMed1999

Tracking of body mass index in children in relation to overweight in adulthood.

Body mass index (BMI; in kg/m2) values at or above the 75th percentile are associated with increased morbidity and mortality in adulthood, and there are significant correlations between BMI values in childhood and in adulthood. The present study addresses the predictive value of childhood BMI for overweight at 35 +/- 5 y, defined as BMI >28 for men and BMI >26 for women. Analyses of data from 555 white children showed that overweight at age 35 y could be predicted from BMI at younger ages. The prediction is excellent at age 18 y, good at age 13 y, but only moderate at ages <13 y. For 18-y-olds with BMIs above the 60th percentile, the probability of overweight at age 35 y is 34% for men and 37% for women. A clinically applicable method is provided to assign an overweight child to a group with a known probability of high BMI values in adulthood.

Journal Article↗
PubMed1999

Aging, body composition, and lifestyle: the Fels Longitudinal Study.

BACKGROUND: Changes in body composition in men and women occur with age, but these changes are affected by numerous covariate factors. OBJECTIVE: The study examined patterns of change in body composition and determined the effects of long-term patterns of change in physical activity in older men and women and in menopausal status and estrogen use in women. DESIGN: Serial measures of height, weight, body mass index (BMI), total body fat (BF), percentage BF, and fat-free mass (FFM) from underwater weighing of 102 men and 108 women enrolled in the Fels Longitudinal Study were analyzed. Physical activity levels and menopausal status were included as covariates. RESULTS: There were significant age-related decreases in FFM and height and increases in total BF, percentage BF, weight, and BMI. Physical activity was associated with decreases in total BF, percentage BF, weight, and BMI in men and were associated with increases in FFM and decreases in total BF and percentage BF in women. Postmenopausal women had significantly higher total BF and percentage BF than did pre- and perimenopausal women. The longer the time since menopause the greater were the increases in weight, BMI, total BF, and percentage BF; however, estrogen use attenuated these increases. CONCLUSIONS: Low FFM can be improved by increased physical activity. The effects of an intervention program on body composition can be masked if only body weight or BMI is measured. The effects of physical activity were more profound in postmenopausal than in premenopausal women, and estrogen use had beneficial effects on body composition.

Adult↗
PubMed1999

Body mass and bone mineral quality.

During adulthood, the amount and quality of muscle and bone mineral decreases, whereas fat increases. Persons with low muscle mass and bone quality may not have the physical or structural strength to support the body. The dual-energy x-ray absorptiometer is used to measure the amount of muscle, fat, and the quality of bone mineral. Men have larger average amounts of muscle and bone, and greater average bone density than women. In women, the normal decrease of body mass and bone quality is accentuated by menopause. On average, blacks have a larger amount of muscle and more dense bones than whites. A person with a high peak bone mass can lose bone normally with age and still maintain good bone quality. Lifestyle, diet, and exercise are important to maintaining a healthy body and good bone quality. Physically active persons have increased levels of muscle and bone density. Age, sex, race, and lifestyle affect the level of, and changes in, body mass and bone mineral density.

Aged↗