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Sample records for growth hormone-insulin-like growth

  1. Growth hormone, insulin-like growth factor system and carcinogenesis.

    PubMed

    Boguszewski, Cesar Luiz; Boguszewski, Margaret Cristina da Silva; Kopchick, John J

    2016-01-01

    The growth hormone (GH) and insulin-like growth factor (IGF) system plays an important role in the regulation of cell proliferation, differentiation, apoptosis, and angiogenesis. In terms of cell cycle regulation, the GH-IGF system induces signalling pathways for cell growth that compete with other signalling systems that result in cell death; thus the final effect of these opposed forces is critical for normal and abnormal cell growth. The association of the GH-IGF system with carcinogenesis has long been hypothesised, mainly based on in vitro studies and the use of a variety of animal models of human cancer, and also on epidemiological and clinical evidence in humans. While ample experimental evidence supports a role of the GH-IGF system in tumour promotion and progression, with several of its components being currently tested as central targets for cancer therapy, the strength of evidence from patients with acromegaly, GH deficiency, or treated with GH is much weaker. In this review, we will attempt to consolidate this data. (Endokrynol Pol 2016; 67 (4): 414-426). PMID:27387246

  2. Effect of sericin on diabetic hippocampal growth hormone/insulin-like growth factor 1 axis

    PubMed Central

    Chen, Zhihong; Yang, Songhe; He, Yaqiang; Song, Chengjun; Liu, Yongping

    2013-01-01

    Previous studies have shown that sericin extracted from silk cocoon significantly reduces blood glucose levels and protects the nervous system against diabetes mellitus. In this study, a rat type 2 diabetes mellitus model was established by intraperitoneal injection of 25 mg/kg streptozotocin for 3 successive days, following which the rats were treated with sericin for 35 days. After treatment, the blood glucose levels of the diabetic rats decreased significantly, the growth hormone level in serum and its expression in the hippocampus decreased significantly, while the insulin-like growth factor-1 level in serum and insulin-like growth factor-1 and growth hormone receptor expression in the hippocampus increased significantly. The experimental findings indicate that sericin improves disorders of the growth hormone/insulin-like growth factor 1 axis to alleviate hippocampal damage in diabetic rats. PMID:25206472

  3. Diabetes, growth hormone-insulin-like growth factor pathways and association to benign prostatic hyperplasia.

    PubMed

    Wang, Zongwei; Olumi, Aria F

    2011-01-01

    Diabetes significantly increases the risk of benign prostatic hyperplasia (BPH) and low urinary tract symptoms (LUTS). The major endocrine aberration in connection with the metabolic syndrome is hyperinsulinemia. Insulin is an independent risk factor and a promoter of BPH. Insulin resistance may change the risk of BPH through several biological pathways. Hyperinsulinemia stimulates the liver to produce more insulin-like growth factor (IGF), another mitogen and an anti-apoptotic agent which binds insulin receptor/IGF receptor and stimulates prostate growth. The levels of IGFs and IGF binding proteins (IGFBPs) in prostate tissue and in blood are associated with BPH risk, with the regulation of circulating androgen and growth hormone. Stromal-epithelial interactions play a critical role in the development and growth of the prostate gland and BPH. Previously, we have shown that the expression of c-Jun in the fibroblastic stroma can promote secretion of IGF-I, which stimulates prostate epithelial cell proliferation through activating specific target genes. Here, we will review the epidemiologic, clinical, and molecular findings which have evaluated the relation between diabetes and development of BPH. PMID:21536370

  4. Growth hormone, insulin-like growth factor-1 and the aging brain.

    PubMed

    Ashpole, Nicole M; Sanders, Jessica E; Hodges, Erik L; Yan, Han; Sonntag, William E

    2015-08-01

    Growth hormone (GH) and insulin-like growth factor (IGF)-1 regulate the development and function of cells throughout the body. Several clinical diseases that result in a decline in physical and mental functions are marked by mutations that disrupt GH or IGF-1 signaling. During the lifespan there is a robust decrease in both GH and IGF-1. Because GH and IGF-1 are master regulators of cellular function, impaired GH and IGF-1 signaling in aging/disease states leads to significant alterations in tissue structure and function, especially within the brain. This review is intended to highlight the effects of the GH and IGF-1 on neuronal structure, function, and plasticity. Furthermore, we address several potential mechanisms through which the age-related reductions in GH and IGF-1 affect cognition. Together, the studies reviewed here highlight the importance of maintaining GH and IGF-1 signaling in order to sustain proper brain function throughout the lifespan. PMID:25300732

  5. Acute alterations in growth hormone-insulin-like growth factor axis in humans injected with endotoxin.

    PubMed

    Lang, C H; Pollard, V; Fan, J; Traber, L D; Traber, D L; Frost, R A; Gelato, M C; Prough, D S

    1997-07-01

    The purpose of the present study was to characterize the acute changes in the insulin-like growth factor (IGF) system in humans after administration of endotoxin (lipopolysaccharide; LPS). Escherichia coli LPS (4 ng/kg) was injected intravenously into healthy adults, and serial blood samples were collected for the next 5 h; subjects injected with saline served as time-matched controls. LPS administration resulted in a gradual decrease in the total extractable IGF-I concentration, which was reduced by approximately 20% over the final 2 h of the experiment; levels of free IGF-I were not significantly altered. LPS also produced a marked but transient elevation in growth hormone (GH) concentration. IGF-binding protein (BP)-1 levels were elevated more than fivefold 2 h after LPS injection, and thereafter levels gradually returned toward baseline. IGFBP-2 concentration also increased after LPS injection, but the maximal increase (approximately 50% above basal) was observed during the final 2 h of the protocol. In contrast, IGFBP-3 levels did not vary over the period examined in response to LPS, and there was no apparent increase in number of BP-3 proteolytic fragments. Cortisol levels were increased early and remained two- to threefold above baseline throughout the protocol. No significant alterations in serum concentration of glucose or insulin were noted. LPS also produced an early elevation in tumor necrosis factor and a later increase in interleukin-6. These data indicate that the acute changes in the GH-IGF axis in humans in response to LPS are comparable with those observed in humans in other traumatic conditions and in animal models of endotoxemia and infection. PMID:9249574

  6. Chronic alterations in growth hormone/insulin-like growth factor-I signaling lead to changes in mouse tendon structure.

    PubMed

    Nielsen, R H; Clausen, N M; Schjerling, P; Larsen, J O; Martinussen, T; List, E O; Kopchick, J J; Kjaer, M; Heinemeier, K M

    2014-02-01

    The growth hormone/insulin-like growth factor-I (GH/IGF-I) axis is an important stimulator of collagen synthesis in connective tissue, but the effect of chronically altered GH/IGF-I levels on connective tissue of the muscle-tendon unit is not known. We studied three groups of mice; 1) giant transgenic mice that expressed bovine GH (bGH) and had high circulating levels of GH and IGF-I, 2) dwarf mice with a disrupted GH receptor gene (GHR-/-) leading to GH resistance and low circulating IGF-I, and 3) a wild-type control group (CTRL). We measured the ultra-structure, collagen content and mRNA expression (targets: GAPDH, RPLP0, IGF-IEa, IGF-IR, COL1A1, COL3A1, TGF-β1, TGF-β2, TGF-β3, versican, scleraxis, tenascin C, fibronectin, fibromodulin, decorin) in the Achilles tendon, and the mRNA expression was also measured in calf muscle (same targets as tendon plus IGF-IEb, IGF-IEc). We found that GHR-/- mice had significantly lower collagen fibril volume fraction in Achilles tendon, as well as decreased mRNA expression of IGF-I isoforms and collagen types I and III in muscle compared to CTRL. In contrast, the mRNA expression of IGF-I isoforms and collagens in bGH mice was generally high in both tendon and muscle compared to CTRL. Mean collagen fibril diameter was significantly decreased with both high and low GH/IGF-I signaling, but the GHR-/- mouse tendons were most severely affected with a total loss of the normal bimodal diameter distribution. In conclusion, chronic manipulation of the GH/IGF-I axis influenced both morphology and mRNA levels of selected genes in the muscle-tendon unit of mice. Whereas only moderate structural changes were observed with up-regulation of GH/IGF-I axis, disruption of the GH receptor had pronounced effects upon tendon ultra-structure. PMID:24080228

  7. Role of growth hormone, insulin-like growth factor-I, and insulin-like growth factor binding proteins in the catabolic response to injury and infection.

    PubMed

    Lang, Charles H; Frost, Robert A

    2002-05-01

    The erosion of lean body mass resulting from protracted critical illness remains a significant risk factor for increased morbidity and mortality in this patient population. Previous studies have documented the well known impairment in nitrogen balance results from both an increase in muscle protein degradation as well as a decreased rate of both myofibrillar and sacroplasmic protein synthesis. This protein imbalance may be caused by an increased presence or activity of various catabolic agents, such as tumor necrosis factor-alpha, interleukin-1 beta, interleukin-6 or glucocorticoids, or may be mediated via a decreased concentration or responsiveness to various anabolic hormones, such as growth hormone or insulin-like growth factor-I. This review focuses on recent developments pertaining to the importance of alterations in the growth hormone-insulin-like growth factor-I axis as a mechanism for the observed defects in muscle protein balance. PMID:11953652

  8. Molecular genetics of human growth hormone, insulin-like growth factors and their pathways in common disease.

    PubMed

    Rodriguez, Santiago; Gaunt, Tom R; Day, Ian N M

    2007-08-01

    The human growth hormone gene (GH1) and the insulin-like growth factor 1 and 2 genes (IGF1 and IGF2) encode the central elements of a key pathway influencing growth in humans. This "growth pathway" also includes transcription factors, agonists, antagonists, receptors, binding proteins, and endocrine factors that constitute an intrincate network of feedback loops. GH1 is evolutionarily coupled with other genes in linkage disequilibrium in 17q24.2, and the same applies to IGF2 in 11p15.5. In contrast, IGF1 in 12q22-24.1 is not in strong linkage disequilibrium with neighbouring genes. Knowledge of the functional architecture of these regions is important for the understanding of the combined evolution and function of GH1, IGF2 and IGF1 in relation to complex diseases. A number of mutations accounting for rare Mendelian disorders have been described in GH-IGF elements. The constellation of genes in this key pathway contains potential candidates in a number of complex diseases, including growth disorders, metabolic syndrome, diabetes (notably IGF2BP2) cardiovascular disease, and central nervous system diseases, and in longevity, aging and cancer. We review these genes and their associations with disease phenotypes, with special attention to metabolic risk traits. PMID:17534663

  9. Influences of the environment on the endocrine and paracrine fish growth hormone-insulin-like growth factor-I system.

    PubMed

    Reinecke, M

    2010-04-01

    Insulin-like growth factor-I (IGF-I) is a key component of the complex system that regulates differentiation, development, growth and reproduction of fishes. The IGF-I gene is mainly expressed in the liver that represents the principal source of endocrine IGF-I but also in numerous other organs where the hormone most probably acts in an autocrine-paracrine manner. The primary stimulus for synthesis and release of IGF-I is growth hormone (GH) from the anterior pituitary. Thus, in analogy to mammals, it is usual to speak of a fish 'GH-IGF-I axis'. The GH-IGF-I system is affected by changes in the environment and probably represents a target of endocrine disrupting compounds (EDC) that impair many physiological processes in fishes. Thus, the review deals with the influences of changes in different environmental factors, such as food availability, temperature, photoperiod, season, salinity and EDCs, on GH gene expression in pituitary, IGF-I gene expression in liver and extrahepatic sites and the physiological effects resulting from the evoked alterations in endocrine and local IGF-I. Environmental influences certainly interact with each other but for convenience of the reader they will be dealt with in separate sections. Current trends in GH-IGF-I research are analysed and future focuses are suggested at the end of the sections. PMID:20537012

  10. Seasonal regulation of the growth hormone-insulin-like growth factor-I axis in the American black bear (Ursus americanus).

    PubMed

    Blumenthal, Stanley; Morgan-Boyd, Rebecca; Nelson, Ralph; Garshelis, David L; Turyk, Mary E; Unterman, Terry

    2011-10-01

    The American black bear maintains lean body mass for months without food during winter denning. We asked whether changes in the growth hormone/insulin-like growth factor-I (GH-IGF-I) axis may contribute to this remarkable adaptation to starvation. Serum IGF-I levels were measured by radioimmunoassay, and IGF-binding proteins (IGFBPs) were analyzed by ligand blotting. Initial studies in bears living in the wild showed that IGF-I levels are highest in summer and lowest in early winter denning. Detailed studies in captive bears showed that IGF-I levels decline in autumn when bears are hyperphagic, continue to decline in early denning, and later rise above predenning levels despite continued starvation in the den. IGFBP-2 increased and IGFBP-3 decreased in early denning, and these changes were also reversed in later denning. Treatment with GH (0.1 mg·kg(-1)·day(-1) × 6 days) during early denning increased serum levels of IGF-I and IGFBP-3 and lowered levels of IGFBP-2, indicating that denning bears remain responsive to GH. GH treatment lowered blood urea nitrogen levels, reflecting effects on protein metabolism. GH also accelerated weight loss and markedly increased serum levels of free fatty acids and β-hydroxybutyrate, resulting in a ketoacidosis (bicarbonate decreased to 15 meq/l), which was reversed when GH was withdrawn. These results demonstrate seasonal regulation of GH/IGF-I axis activity in black bears. Diminished GH activity may promote fat storage in autumn in preparation for denning and prevent excessive mobilization and premature exhaustion of fat stores in early denning, whereas restoration of GH/IGF activity in later denning may prepare the bear for normal activity outside the den. PMID:21730258

  11. Growth and the Growth Hormone-Insulin Like Growth Factor 1 Axis in Children With Chronic Inflammation: Current Evidence, Gaps in Knowledge, and Future Directions.

    PubMed

    Wong, S C; Dobie, R; Altowati, M A; Werther, G A; Farquharson, C; Ahmed, S F

    2016-02-01

    Growth failure is frequently encountered in children with chronic inflammatory conditions like juvenile idiopathic arthritis, inflammatory bowel disease, and cystic fibrosis. Delayed puberty and attenuated pubertal growth spurt are often seen during adolescence. The underlying inflammatory state mediated by proinflammatory cytokines, prolonged use of glucocorticoid, and suboptimal nutrition contribute to growth failure and pubertal abnormalities. These factors can impair growth by their effects on the GH-IGF axis and also directly at the level of the growth plate via alterations in chondrogenesis and local growth factor signaling. Recent studies on the impact of cytokines and glucocorticoid on the growth plate further advanced our understanding of growth failure in chronic disease and provided a biological rationale of growth promotion. Targeting cytokines using biological therapy may lead to improvement of growth in some of these children, but approximately one-third continue to grow slowly. There is increasing evidence that the use of relatively high-dose recombinant human GH may lead to partial catch-up growth in chronic inflammatory conditions, although long-term follow-up data are currently limited. In this review, we comprehensively review the growth abnormalities in children with juvenile idiopathic arthritis, inflammatory bowel disease, and cystic fibrosis, systemic abnormalities of the GH-IGF axis, and growth plate perturbations. We also systematically reviewed all the current published studies of recombinant human GH in these conditions and discussed the role of recombinant human IGF-1. PMID:26720129

  12. Rearing Mozambique tilapia in tidally-changing salinities: Effects on growth and the growth hormone/insulin-like growth factor I axis.

    PubMed

    Moorman, Benjamin P; Yamaguchi, Yoko; Lerner, Darren T; Grau, E Gordon; Seale, Andre P

    2016-08-01

    The growth hormone (GH)/insulin-like growth factor (IGF) axis plays a central role in the regulation of growth in teleosts and has been shown to be affected by acclimation salinity. This study was aimed at characterizing the effects of rearing tilapia, Oreochromis mossambicus, in a tidally-changing salinity on the GH/IGF axis and growth. Tilapia were raised in fresh water (FW), seawater (SW), or in a tidally-changing environment, in which salinity is switched between FW (TF) and SW (TS) every 6h, for 4months. Growth was measured over all time points recorded and fish reared in a tidally-changing environment grew significantly faster than other groups. The levels of circulating growth hormone (GH), insulin-like growth factor I (IGF-I), pituitary GH mRNA, gene expression of IGF-I, IGF-II, and growth hormone receptor 2 (GHR) in the muscle and liver were also determined. Plasma IGF-I was higher in FW and TS than in SW and TF tilapia. Pituitary GH mRNA was higher in TF and TS than in FW and SW tilapia. Gene expression of IGF-I in the liver and of GHR in both the muscle and liver changed between TF and TS fish. Fish growth was positively correlated with GH mRNA expression in the pituitary, and GHR mRNA expression in muscle and liver tissues. Our study indicates that rearing fish under tidally-changing salinities elicits a distinct pattern of endocrine regulation from that observed in fish reared in steady-state conditions, and may provide a new approach to increase tilapia growth rate and study the regulation of growth in euryhaline fish. PMID:27032617

  13. Time dependent impact of perinatal hypoxia on growth hormone, insulin-like growth factor 1 and insulin-like growth factor binding protein-3.

    PubMed

    Kartal, Ömer; Aydınöz, Seçil; Kartal, Ayşe Tuğba; Kelestemur, Taha; Caglayan, Ahmet Burak; Beker, Mustafa Caglar; Karademir, Ferhan; Süleymanoğlu, Selami; Kul, Mustafa; Yulug, Burak; Kilic, Ertugrul

    2016-08-01

    Hypoxic-ischemia (HI) is a widely used animal model to mimic the preterm or perinatal sublethal hypoxia, including hypoxic-ischemic encephalopathy. It causes diffuse neurodegeneration in the brain and results in mental retardation, hyperactivity, cerebral palsy, epilepsy and neuroendocrine disturbances. Herein, we examined acute and subacute correlations between neuronal degeneration and serum growth factor changes, including growth hormone (GH), insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3) after hypoxic-ischemia (HI) in neonatal rats. In the acute phase of hypoxia, brain volume was increased significantly as compared with control animals, which was associated with reduced GH and IGF-1 secretions. Reduced neuronal survival and increased DNA fragmentation were also noticed in these animals. However, in the subacute phase of hypoxia, neuronal survival and brain volume were significantly decreased, accompanied by increased apoptotic cell death in the hippocampus and cortex. Serum GH, IGF-1, and IGFBP-3 levels were significantly reduced in the subacute phase of HI. Significant retardation in the brain and body development were noted in the subacute phase of hypoxia. Here, we provide evidence that serum levels of growth-hormone and factors were decreased in the acute and subacute phase of hypoxia, which was associated with increased DNA fragmentation and decreased neuronal survival. PMID:26943480

  14. Stimulatory effect of luteinizing hormone, insulin-like growth factor-1, and epidermal growth factor on vascular endothelial growth factor production in cultured bubaline luteal cells.

    PubMed

    Chouhan, V S; Dangi, S S; Babitha, V; Verma, M R; Bag, S; Singh, G; Sarkar, M

    2015-10-15

    The purpose of this study was to evaluate the temporal (24, 48, and 72 hours) and dose-dependent (0, 5, 10, and 100 ng/mL of LH, insulin-like growth factor 1 [IGF-1], and EGF) in vitro expression and secretion patterns of vascular endothelial growth factor (VEGF) in luteal cell culture during different stages of estrous cycle in water buffaloes. Corpus luteum samples from ovaries of early luteal phase (ELP; Days 1-4), midluteal phase (Days 5-10), and late luteal phase (Days 11-16) were collected from a local slaughterhouse. The samples were then processed and cultured in (serum containing) appropriate cell culture medium and incubated separately with three factors (LH, IGF-1, or EGF) at the previously mentioned three dose-duration combinations. At the end of the respective incubation periods, VEGF was assayed in the spent culture medium by ELISA, whereas the cultured cells were used for VEGF mRNA expression by quantitative real-time polymerase chain reaction. The results of the present study disclosed dose- and time-dependent stimulatory effects of LH, IGF-1, and EGF on VEGF production in bubaline luteal cells. The VEGF expression and secretion from the cultured luteal cells were highest during the ELP, intermediate in the midluteal phase, and lowest in the late luteal phase of the estrous cycle for all the three tested factors. Comparison of the results of the three treatments depicted EGF as the most potent stimulating factor followed by IGF-1 and LH. Immunocytochemistry findings in luteal cell culture of ELP agreed with the VEGF expression and secretion. In conclusion, mRNA expression, protein secretion, and immunolocalization of VEGF data clearly indicated for the first time that LH, IGF-1, and EGF play an important role in stimulating luteal angiogenesis in buffalo CL. The highest expression and secretion of VEGF in the ELP might be associated with the development of blood vessels in early growth of CL, which in turn gets augmented by the aforementioned

  15. Effects of sericin on the testicular growth hormone/insulin-like growth factor-1 axis in a rat model of type 2 diabetes

    PubMed Central

    Song, Cheng-Jun; Yang, Zhen-Jun; Tang, Qi-Feng; Chen, Zhi-Hong

    2015-01-01

    This study investigated the effects of sericin on the testicular growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis in rats with type 2 diabetes mellitus. Forty rats were randomly assigned to normal control, type 2 diabetes mellitus, sericin and metformin treated groups. Type 2 diabetes was established by repeated intraperitoneal injection of streptozotocin, and identified by blood glucose ≥16.7 mmol/L at 1 week. The diabetic rats were given no other treatment, these rats in the sericin group were intragastrically perfused with 2.4 g/kg sericin and the metformin treated rats were intragastrically perfused with 55.33 mg/kg Metformin daily for 35 consecutive days. Enzyme-linked immunosorbent assays were used to determine serum testosterone, growth hormone and IGF-1 levels. Immunohistochemical staining, western blotting and reverse transcription-PCR were used to determine testicular growth hormone, growth hormone receptor and IGF-1 expression. The sericin significantly reduced serum growth hormone levels, downregulated growth hormone expression, increased serum testosterone and IGF-1 levels, and upregulated testicular growth hormone receptor and IGF-1 expression. Moreover, there were no significant differences in any of the parameters between the sericin and metformin treated groups. These findings indicated that sericin improved spermatogenic function through regulating the growth hormone/IGF-1 axis, thereby protecting reproductive function against diabetes-induced damage. PMID:26379831

  16. Effects of sericin on the testicular growth hormone/insulin-like growth factor-1 axis in a rat model of type 2 diabetes.

    PubMed

    Song, Cheng-Jun; Yang, Zhen-Jun; Tang, Qi-Feng; Chen, Zhi-Hong

    2015-01-01

    This study investigated the effects of sericin on the testicular growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis in rats with type 2 diabetes mellitus. Forty rats were randomly assigned to normal control, type 2 diabetes mellitus, sericin and metformin treated groups. Type 2 diabetes was established by repeated intraperitoneal injection of streptozotocin, and identified by blood glucose ≥16.7 mmol/L at 1 week. The diabetic rats were given no other treatment, these rats in the sericin group were intragastrically perfused with 2.4 g/kg sericin and the metformin treated rats were intragastrically perfused with 55.33 mg/kg Metformin daily for 35 consecutive days. Enzyme-linked immunosorbent assays were used to determine serum testosterone, growth hormone and IGF-1 levels. Immunohistochemical staining, western blotting and reverse transcription-PCR were used to determine testicular growth hormone, growth hormone receptor and IGF-1 expression. The sericin significantly reduced serum growth hormone levels, downregulated growth hormone expression, increased serum testosterone and IGF-1 levels, and upregulated testicular growth hormone receptor and IGF-1 expression. Moreover, there were no significant differences in any of the parameters between the sericin and metformin treated groups. These findings indicated that sericin improved spermatogenic function through regulating the growth hormone/IGF-1 axis, thereby protecting reproductive function against diabetes-induced damage. PMID:26379831

  17. Evidence for growth hormone/insulin-like growth factor I axis regulation of seawater acclimation in the euryhaline teleost Fundulus heteroclitus

    USGS Publications Warehouse

    Mancera, J.M.; McCormick, S.D.

    1998-01-01

    The ability of ovine growth hormone (oGH), recombinant bovine insulin- like growth factor I (rbIGF-I), recombinant human insulin-like growth factor II (rhIGF-II), and bovine insulin to increase hypoosmoregulatory capacity in the euryhaline teleost Fundulus heteroclitus was examined. Fish acclimated to brackish water (BW, 10 ppt salinity, 320 mOsm/kg H2O) were injected with a single dose of hormone and transferred to seawater (SW, 35 ppt salinity, 1120 mOsm/kg H2O) 2 days later. Fish were sampled 24 h after transfer and plasma osmolality, plasma glucose, and gill Na+,K+-ATPase activity were examined. Transfer from BW to SW increased plasma osmolality and gill Na+,K+-ATPase activity. Transfer from BW to BW had no effect on these parameters. rbIGF-I (0.05, 0.1, and 0.2 ??g/g) improved the ability to maintain plasma osmolality and to increase gill Na+, K+-ATPase activity in a dose-dependent manner. oGH (0.5, 1, and 2 ??g/g) also increased hypoosmoregulatory ability but only the higher doses (2 ??g/g) significantly increased gill Na+,K+-ATPase activity. oGH (1 ??g/g) and rbIGF-I (0.1 ??g/g) had a significantly greater effect on plasma osmolality and gill Na+,K+-ATPase activity than either hormone alone. rhIGF-II (0.05, 0.1, and 0.2 ??g/g) and bovine insulin (0.01 and 0.05 ??g/g) were without effect. The results suggest a role of GH and insulin-like growth factor I (IGF-I) in seawater acclimation of E heteroclitus. Based on these findings and previous studies, it is concluded that the capacity of the GH/IGF-I axis to increase hypoosmoregulatory ability may be a common feature of euryhalinity in teleosts.

  18. Effects of somatostatin on the growth hormone-insulin-like growth factor axis and seawater adaptation of rainbow trout (Oncorhynchus mykiss)

    USGS Publications Warehouse

    Poppinga, J.; Kittilson, J.; McCormick, S.D.; Sheridan, M.A.

    2007-01-01

    Growth hormone (GH) has been shown to contribute to the seawater (SW) adaptability of euryhaline fish both directly and indirectly through insulin-like growth factor-1 (IGF-1). This study examined the role of somatostatin-14 (SS-14), a potent inhibitor of GH, on the GH-IGF-1 axis and seawater adaptation. Juvenile rainbow trout (Oncorhynchus mykiss) were injected intraperitoneally with SS-14 or saline and transferred to 20??ppt seawater. A slight elevation in plasma chloride levels was accompanied by significantly reduced gill Na+, K+-ATPase activity in SS-14-treated fish compared to control fish 12??h after SW transfer. Seawater increased hepatic mRNA levels of GH receptor 1 (GHR 1; 239%), GHR 2 (48%), and IGF-1 (103%) in control fish 12??h after transfer. Levels of GHR 1 (155%), GHR 2 (121%), IGF-1 (200%), IGF-1 receptor A (IGFR1A; 62%), and IGFR1B (157%) increased in the gills of control fish 12??h after transfer. SS-14 abolished or attenuated SW-induced changes in the expression of GHR, IGF-1, and IGFR mRNAs in liver and gill. These results indicate that SS-14 reduces seawater adaptability by inhibiting the GH-IGF-1 axis. ?? 2007 Elsevier B.V. All rights reserved.

  19. Changes in tissue levels of growth hormone, insulin-like growth factor-I, and somatostatin in the femurs of hind-limb immobilized rats.

    PubMed

    Suliman, I A; Elhassan, A M; Adem, A; El-Bakri, N K; Lindgren, J U

    2001-04-01

    Immobilization of an extremity causes skeletal muscle atrophy and a dramatic increase in bone resorption. Growth hormone (GH) is known to play an important role in bone remodeling mediated in part by local insulin-like growth factor-I (IGF-I). In this study, we investigated changes in the levels of GH and IGF-I peptide in bone extracts from the femur after hind-limb immobilization for 5 days, 2, 4, and 8 weeks. The levels of somatostatin, which interacts with GH, were also measured in the bone extracts. GH levels increased after 8 weeks of hind-limb immobilization whereas the IGF-I concentrations increased after 2 weeks, but returned to control levels at 4 weeks, and decreased after 8 weeks of immobilization. The somatostatin levels in the bone extracts increased only after 8 weeks of hind-limb immobilization. Our findings suggest that, after hind-limb immobilization, changes in the concentrations of GH, IGF-I, and somatostatin in bone may mediate bone resorption either directly or through interaction with other factors. PMID:11372951

  20. Differential impact of simple childhood obesity on the components of the growth hormone-insulin-like growth factor (IGF)-IGF binding proteins axis.

    PubMed

    Ballerini, María Gabriela; Ropelato, María Gabriela; Domené, Horacio Mario; Pennisi, Patricia; Heinrich, Juan Jorge; Jasper, Héctor Guillermo

    2004-05-01

    Simple childhood obesity is characterized by normal or even accelerated growth in spite of reduced growth hormone (GH) secretion. There are conflicting reports on the effects of obesity upon components of the GH-insulin-like growth factor-I (IGF-I)-IGF binding proteins (IGFBPs) system. In the present study we aimed to determine GH, IGF-I, IGFBP-3 and IGFBP-2 as well as some of the less explored components of this axis (IGFBP-3 proteolytic activity, IGFBP-3 plasma fragments, and total acid labile subunit [ALS]) in 22 obese and 17 age-matched control children. We also evaluated not only total GH binding protein (GHBP) serum levels but also GHBP bound to GH (complexed) in both groups. Obese and control groups strongly differed in BMI (obese: 4.7 +/- 0.36 vs control: 0.37 +/- 0.25 SDS, p <0.0001). In the obese group, we found lower GH serum levels, but normal serum levels of GH-GHBP complex, IGF-I, IGFBP-3, IGF-I/IGFBP-3 molar ratio, IGFBP-3 proteolytic activity, IGFBP-3 plasma fragments and total ALS. Obese children presented higher total circulating GHBP (6.0 +/- 0.44 vs 2.9 +/- 0.29 nmol/l, p <0.001) and insulin levels (10.5 +/- 1.5 vs 5.1 +/- 0.8 mU/l, p <0.001), while IGFBP-2 (4.6 +/- 0.5 vs 6.6 +/- 0.7%, p <0.05) and the ratio IGFBP-2/IGF-I (0.032 +/- 0.019 vs 0.095 +/- 0.01, p = 0.013) were lower than in controls. BMI and insulin were directly, and IGFBP-2 serum levels inversely, correlated to total GHBP serum levels when multiple regression analysis was performed (r = 0.74, p <0.001). By stepwise regression analysis, insulin (r = -0.37, p <0.05) and BMI (r = -0.52, p <0.01) inversely determined IGFBP-2. In summary, obese children present normal growth in spite of reduced GH secretion, probably because the combination of increased total GHBP and normal GH-GHBP complex serum levels (suggesting increased GH receptor [GHR] number and a normal serum GH reservoir, respectively) allow for the achievement of normal levels of IGF-I, IGFBP-3, IGFBP-3 proteolytic activity

  1. Stimulatory effect of luteinizing hormone, insulin-like growth factor-1, and epidermal growth factor on progesterone secretion and viability of cultured bubaline luteal cells.

    PubMed

    Chouhan, V S; Dangi, S S; Vazhoor, B; Yadav, V P; Gupta, M; Pathak, M C; Panda, R P; Khan, F A; Verma, M R; Maurya, V P; Singh, G; Sarkar, M

    2014-12-01

    We evaluated the temporal (24, 48 and 72 hours) and dose-dependent (5, 10, and 100 ng/mL of LH, IGF-1, and EGF, respectively) production and secretion of progesterone (P4) in cultured luteal cells from different stages of estrous cycle as well as the expression of steroidogenic acute regulatory protein (STARD1), cytochrome P450 cholesterol side-chain cleavage (CYP11A1), and 3β-hydroxysteroid dehydrogenase (HSD3B), anti-apoptotic gene PCNA, and pro-apoptotic gene BAX in luteal cells of mid-luteal phase in buffalo. Samples from early luteal phase (ELP; Day 1 to 4; n = 4), mid-luteal phase (MLP; Day 5 to 10; n = 4), and late luteal phase (LLP; Day 11 to 16; n = 4) of estrous cycle were collected. Progesterone was assayed by RIA, whereas mRNA expression was determined by quantitative real-time polymerase chain reaction. Results depicted that highest dose (100 ng/mL) of LH, IGF-1, and EGF and longer duration of time brought about a (P < 0.05) rise in P4 level and expression of steroidogenic enzymes and PCNA compared with the lower level(s) and control while, all treatments (P < 0.05) inhibited BAX expression in a time dependent-manner. Analysis of interaction between stage and treatments revealed that LH treatment (P < 0.05) increased P4 production compared with IGF-1 and EGF in ELP and MLP. However in LLP, treatment with IGF-1 and EGF significantly (P < 0.05) increased P4 production compared with LH treatment. Summarizing, our study explores the steroidogenic potential of LH and growth factors across different luteal stages in buffalo, which on promoting steroidogenic enzyme expression and cell viability culminated in enhanced P4 production in luteal cells. PMID:25263485

  2. Smartamine M and MetaSmart supplementation during the peripartal period alter hepatic expression of gene networks in 1-carbon metabolism, inflammation, oxidative stress, and the growth hormone-insulin-like growth factor 1 axis pathways.

    PubMed

    Osorio, J S; Ji, P; Drackley, J K; Luchini, D; Loor, J J

    2014-12-01

    Peripartal cows likely require greater amounts of Met not only at the tissue and cell level for methylation reactions but also for milk protein synthesis after calving. Thirty-nine Holstein cows were fed throughout the peripartal period (-21 d to 30 d in milk) a basal control (CON) diet (n=14) with no Met supplementation, CON plus MetaSmart (MS; Adisseo Inc., Antony, France; n=12), or CON plus Smartamine M (SM; Adisseo Inc.; n=13). The Met supplements were adjusted daily and top-dressed over the total mixed ration at a rate of 0.19 or 0.07% (dry matter) of feed for MS or SM. Liver tissue was collected on -10, 7, and 21 d for transcriptome profiling of genes associated with Met and glutathione metabolism as well as components of the inflammation, oxidative stress, growth hormone/insulin-like growth factor-1 axis, and DNA methylation pathways. Data were analyzed using PROC MIXED of SAS (SAS Institute Inc., Cary, NC) with the preplanned contrasts CON versus SM + MS and SM versus MS. The S-adenosylhomocysteine hydrolase (SAHH) gene was the most abundant among all genes evaluated, with overall greater expression in Met-supplemented cows than CON, and in SM than MS. Expression of Met adenosyltransferase 1A (MAT1A) was greater in Met-supplemented cows than CON by 21 d postpartum. A greater overall expression of 5-methyltetrahydrofolate-homocysteine methyltransferase (MTR) occurred in Met-supplemented cows than CON. In contrast, the expression of glutathione synthase (GSS); glutamate-cysteine ligase, catalytic subunit (GCLC); and superoxide dismutase 1, cytosolic (SOD1) was lower in Met-supplemented cows than CON. A greater overall expression of nuclear factor of kappa light polypeptide gene enhancer in B-cells 1 (NFKB1) and greater upregulation of haptoglobin (HP) on d 7 occurred in Met-supplemented cows than CON. Expression of DNA cytosine-5-methyltransferase 3 alpha (DNMT3A) was greater but expression of DNMT1 was lower in Met-supplemented cows than CON. The response

  3. Tissue-specific regulation of the growth hormone/insulin-like growth factor axis during fasting and re-feeding: Importance of muscle expression of IGF-I and IGF-II mRNA in the tilapia.

    PubMed

    Fox, Bradley K; Breves, Jason P; Davis, Lori K; Pierce, Andrew L; Hirano, Tetsuya; Grau, E Gordon

    2010-05-01

    The effects of prolonged nutrient restriction (fasting) and subsequent restoration (re-feeding) on the growth hormone (GH)/insulin-like growth factor (IGF) axis were investigated in the tilapia (Oreochromis mossambicus). Mean weight and specific growth rate declined within 1 week in fasted fish, and remained lower than controls throughout 4 weeks of fasting. Plasma levels of IGF-I were lower than fed controls during 4 weeks of fasting, suggesting a significant catabolic state. Following re-feeding, fasted fish gained weight continuously, but did not attain the weight of fed controls at 8 weeks after re-feeding. Specific growth rate increased above the continuously-fed controls during the first 6 weeks of re-feeding, clearly indicating a compensatory response. Plasma IGF-I levels increased after 1 week of re-feeding and levels were not otherwise different from fed controls. Plasma GH levels were unaffected by either fasting or re-feeding. No consistent effect of fasting or re-feeding was observed on liver expression of GH receptor (GH-R), somatolactin (SL) receptor (SL-R), IGF-I or IGF-II. In contrast, muscle expression of GH-R increased markedly during 4 weeks of fasting, and then declined below control levels upon re-feeding for weeks 1 and 2. Similarly, muscle expression of SL-R increased after 4 weeks of fasting, and reduced below control levels after 1 and 2 weeks of re-feeding. On the other hand, muscle expression of IGF-I was strongly reduced throughout the fasting period, and levels recovered 2 weeks after re-feeding. Muscle expression of IGF-II was not affected by fasting, but was reduced after 1 and 2 weeks of re-feeding. These results indicate that GH/IGF axis, particularly muscle expression of GH-R, SL-R and IGF-I and -II, is sensitive to nutritional status in the tilapia. PMID:19932110

  4. Single nucleotide polymorphisms in the growth hormone-insulin-like growth factor axis in straightbred and crossbred Angus, Brahman, and Romosinuano heifers: population genetic analyses and association of genotypes with reproductive phenotypes.

    PubMed

    Luna-Nevarez, P; Rincon, G; Medrano, J F; Riley, D G; Chase, C C; Coleman, S W; Vanleeuwen, D M; DeAtley, K L; Islas-Trejo, A; Silver, G A; Thomas, M G

    2011-04-01

    The growth endocrine axis influences reproduction. The objectives of this study were to evaluate population genetic characteristics of SNP genotypes within genes of the GH-IGF axis in straightbred and crossbred Angus, Brahman, and Romosinuano heifers (n = 650) and to test the association of these genotypes with measures of reproduction. These objectives were achieved using 73 SNP within 7 genes on chromosome 5 and the pregnancy-associated plasma protein A2 (PAPP-A2) and GH-receptor genes, which map to chromosomes 16 and 20, respectively. The SNP were elucidated by resequencing conserved regions of each gene by using DNA from familial-unrelated cattle of a multibreed discovery population. A multiplex SNP assay yielded 59 biallelic SNP useful for evaluating genetic identity and distance. Specifically, the divergence of straightbred Brahman cattle was approximately 15.5% from 5 Bos taurus-influenced breed groups. In the straightbred groups used as a validation population, only 3 SNP had minor allele frequencies >10%. These SNP were in the genes PAPP-A2 (ss115492449-A/C and ss115492450-G/T within intron 10) and signal transducers and activators of transcription 2 (STAT2; ss252841035-A/G within the 5' untranslated region), and they met the conditions of Hardy-Weinberg equilibrium (P > 0.31). The other 56 SNP were useful for assigning each animal into ancestral clusters (n = 3 proportions) to account for population stratification in genotype to phenotype association analyses. The 2 SNP in the PAPP-A2 gene influenced (P < 0.05) traits indicative of first-calf heifer rebreeding (i.e., calving interval, days to calving, and pregnancy rate). A STAT2 SNP genotype (i.e., GG) × primary ancestral cluster interaction (P < 0.05) suggested heifers primarily of B. taurus ancestry had a reduction of approximately 16.4 ± 0.1% in calving interval and days to calving relative to heifers clustering primarily as Bos indicus ancestry. Even though additional research is needed to

  5. The growth hormone/insulin-like growth factor axis in critical illness.

    PubMed

    Gelato, M C

    2000-09-01

    Over the past several years, we have studied a variety of clinical conditions that are characterized by significant alterations in the GH/IGF system that might contribute to catabolism. Our studies have focused in detail on IGF-I and -II and the major IGFBPs in the circulation, IGFBP-3, -1, and -2; GH was also measured in some of these studies. In light of a recent study that has raised concerns about the use of GH in critically ill patients, we now review the changes in the GH/IGF axis during critical illness, the interaction between cytokines and the GH/IGF axis, and the safety and efficacy of GH therapy in critical illness. We conclude that it is premature to recommend interruption of GH therapy in patients with documented GH deficiency during periods of acute illness. PMID:11086657

  6. The connection between animal stress and meat production: Uncoupling of the growth hormone/insulin-like growth factor 1 axis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For decades, researchers have demonstrated that "stress" can have detrimental effects on the immune system. However, what had not been distinguished until recently are the divergent effects of "acute" stress associated with subclinical immunological burdens on the animal versus long-term or "chronic...

  7. Effect of Growth Hormone Deficiency on Brain Structure, Motor Function and Cognition

    ERIC Educational Resources Information Center

    Webb, Emma A.; O'Reilly, Michelle A.; Clayden, Jonathan D.; Seunarine, Kiran K.; Chong, Wui K.; Dale, Naomi; Salt, Alison; Clark, Chris A.; Dattani, Mehul T.

    2012-01-01

    The growth hormone-insulin-like growth factor-1 axis plays a role in normal brain growth but little is known of the effect of growth hormone deficiency on brain structure. Children with isolated growth hormone deficiency (peak growth hormone less than 6.7 [micro]g/l) and idiopathic short stature (peak growth hormone greater than 10 [micro]g/l)…

  8. The influence of tropical adaptation on plasma concentrations of insulin-like growth factor-I in purebred and crossbred beef cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In an effort to determine whether tropical adaptation influences circulating concentrations of the growth-related hormone, insulin-like growth factor-I (IGF-I), 3-breed diallel matings were conducted using temperate Bos taurus (A; Angus), tropical Bos indicus (B; Brahman), and tropical Bos taurus (R...

  9. Nutritionally-Induced Catch-Up Growth

    PubMed Central

    Gat-Yablonski, Galia; Phillip, Moshe

    2015-01-01

    Malnutrition is considered a leading cause of growth attenuation in children. When food is replenished, spontaneous catch-up (CU) growth usually occurs, bringing the child back to its original growth trajectory. However, in some cases, the CU growth is not complete, leading to a permanent growth deficit. This review summarizes our current knowledge regarding the mechanism regulating nutrition and growth, including systemic factors, such as insulin, growth hormone, insulin- like growth factor-1, vitamin D, fibroblast growth factor-21, etc., and local mechanisms, including autophagy, as well as regulators of transcription, protein synthesis, miRNAs and epigenetics. Studying the molecular mechanisms regulating CU growth may lead to the establishment of better nutritional and therapeutic regimens for more effective CU growth in children with malnutrition and growth abnormalities. It will be fascinating to follow this research in the coming years and to translate the knowledge gained to clinical benefit. PMID:25594438

  10. Growth

    NASA Astrophysics Data System (ADS)

    Waag, Andreas

    This chapter is devoted to the growth of ZnO. It starts with various techniques to grow bulk samples and presents in some detail the growth of epitaxial layers by metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), and pulsed laser deposition (PLD). The last section is devoted to the growth of nanorods. Some properties of the resulting samples are also presented. If a comparison between GaN and ZnO is made, very often the huge variety of different growth techniques available to fabricate ZnO is said to be an advantage of this material system. Indeed, growth techniques range from low cost wet chemical growth at almost room temperature to high quality MOCVD growth at temperatures above 1, 000∘C. In most cases, there is a very strong tendency of c-axis oriented growth, with a much higher growth rate in c-direction as compared to other crystal directions. This often leads to columnar structures, even at relatively low temperatures. However, it is, in general, not straight forward to fabricate smooth ZnO thin films with flat surfaces. Another advantage of a potential ZnO technology is said to be the possibility to grow thin films homoepitaxially on ZnO substrates. ZnO substrates are mostly fabricated by vapor phase transport (VPT) or hydrothermal growth. These techniques are enabling high volume manufacturing at reasonable cost, at least in principle. The availability of homoepitaxial substrates should be beneficial to the development of ZnO technology and devices and is in contrast to the situation of GaN. However, even though a number of companies are developing ZnO substrates, only recently good quality substrates have been demonstrated. However, these substrates are not yet widely available. Still, the situation concerning ZnO substrates seems to be far from low-cost, high-volume production. The fabrication of dense, single crystal thin films is, in general, surprisingly difficult, even when ZnO is grown on a ZnO substrate. However

  11. THE EFFECTS OF METHIONINE DEFICIENCIES ON PLASMA LEVELS OF THYROID HORMONES, INSULIN-LIKE GROWTH FACTORS I AND II, LIVER AND BODY WEIGHTS, AND FEED INTAKE IN GROWING CHICKENS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A deficiency of methionine (Met) at 0.25% of the diet, or 50% of the National Research Council's recommended level, has been reported to cause elevations in plasma triiodothyronine (T3) in growing broiler chickens. In the present study, plasma levels of thyroid hormones as well as insulin-like grow...

  12. Skeletal effects of growth hormone and insulin-like growth factor-I therapy.

    PubMed

    Lindsey, Richard C; Mohan, Subburaman

    2016-09-01

    The growth hormone/insulin-like growth factor (GH/IGF) axis is critically important for the regulation of bone formation, and deficiencies in this system have been shown to contribute to the development of osteoporosis and other diseases of low bone mass. The GH/IGF axis is regulated by a complex set of hormonal and local factors which can act to regulate this system at the level of the ligands, receptors, IGF binding proteins (IGFBPs), or IGFBP proteases. A combination of in vitro studies, transgenic animal models, and clinical human investigations has provided ample evidence of the importance of the endocrine and local actions of both GH and IGF-I, the two major components of the GH/IGF axis, in skeletal growth and maintenance. GH- and IGF-based therapies provide a useful avenue of approach for the prevention and treatment of diseases such as osteoporosis. PMID:26408965

  13. Growth and bone development.

    PubMed

    Cooper, Cyrus; Harvey, Nicholas; Javaid, Kassim; Hanson, Mark; Dennison, Elaine

    2008-01-01

    Osteoporosis is a major cause of morbidity and mortality through its association with age-related fractures. Although most effort in fracture prevention has been directed at retarding the rate of age-related bone loss, and reducing the frequency and severity of trauma among elderly people, evidence is growing that peak bone mass is an important contributor to bone strength during later life. The normal patterns of skeletal growth have been well characterized in cross-sectional and longitudinal studies. It has been confirmed that boys have higher bone mineral content, but not volumetric bone density, than girls. Furthermore, there is a dissociation between the peak velocities for height gain and bone mineral accrual, in both genders. Puberty is the period during which volumetric density appears to increase in both axial and appendicular sites. Many factors influence the accumulation of bone mineral during childhood and adolescence, including heredity, gender, diet, physical activity, endocrine status, and sporadic risk factors such as cigarette smoking. In addition to these modifiable factors during childhood, evidence has also accrued that fracture risk might be programmed during intrauterine life. Epidemiological studies have demonstrated a relationship between birthweight, weight in infancy, and adult bone mass. This appears to be mediated through modulation of the set-point for basal activity of pituitary-dependent endocrine systems such as the hypothalamicpituitary-adrenal and growth hormone/insulin-like growth factor-1 axes. Maternal smoking, diet (particularly vitamin D deficiency), and physical activity also appear to modulate bone mineral acquisition during intrauterine life; furthermore, both low birth size and poor childhood growth are directly linked to the later risk of hip fracture. The optimization of maternal nutrition and intrauterine growth should also be included within preventive strategies against osteoporotic fracture, albeit for future

  14. Growth hormone receptors in the atherinid Odontesthes bonariensis: characterization and expression profile after fasting-refeeding and growth hormone administration.

    PubMed

    Botta, P E; Simó, I; Sciara, A A; Arranz, S E

    2016-05-01

    In order to improve the understanding of pejerrey Odontesthes bonariensis, growth hormone (Gh)-insulin-like growth factor-1(Igf1) axis, O. bonariensis growth hormone receptor type 1 (ghr1) and type 2 (ghr2) mRNA sequences were obtained. Both transcripts were ubiquitously expressed except in kidney, encephalon and anterior intestine. Alternative transcripts of both receptors were found in muscle. Interestingly, two different ghr2 transcripts with alternative polyadenylation (APA) sites located in the long 3' untranslated region (UTR-APA) were also found in liver. Hepatic ghr1, ghr2 and insulin-like growth factor type 1 (igf1) transcript levels were examined under two different metabolic conditions. In the first experimental condition, fish were fasted for 2 weeks and then re-fed for another 2 weeks. Despite igf1 mRNA relative expression did not show significant differences under the experimental period of time examined, both ghr transcripts decreased their expression levels after the fasting period and returned to their control levels after re-feeding. In the second treatment, recombinant O. bonariensis growth hormone (r-pjGh) was orally administered once a week. After 4 weeks of treatment, liver igf1, ghr1 and ghr2 mRNA relative expression increased (13, 4·5 and 2·1 fold, P < 0·05) compared to control values. These results add novel information to the growth hormone-insulin-like growth factor system in teleosts. PMID:27097742

  15. Growth Disorders

    MedlinePlus

    ... gland problem or disease. The pituitary gland makes growth hormone, which stimulates the growth of bone and other ... of it may be very short. Treatment with growth hormone can stimulate growth. People can also have too ...

  16. Mouth Growths

    MedlinePlus

    ... Dry Mouth Mouth Growths Mouth Sores and Inflammation Toothache Malocclusion Teeth Grinding Recurrent Aphthous Stomatitis Growths can ... Dry Mouth Mouth Growths Mouth Sores and Inflammation Toothache Malocclusion Teeth Grinding Recurrent Aphthous Stomatitis NOTE: This ...

  17. Eyelid Growths

    MedlinePlus

    ... a microscope). The growth is usually removed surgically. Did You Know... A growth on the eyelid that ... respond to initial treatments. Resources In This Article Did You Know 1 Did You Know... Figure 1 ...

  18. Growth Hormone

    MedlinePlus

    ... the dose of glucose. Growth hormone stimulates the production of insulin-like growth factor-1 (IGF-1) . ... regular intervals for years afterward to monitor GH production and to detect tumor recurrence. Other blood tests ...

  19. Delayed growth

    MedlinePlus

    Growth - slow (child 0 - 5 years); Weight gain - slow (child 0 - 5 years); Slow rate of growth; Retarded growth and development; ... A child should have regular, well-baby check-ups with a health care provider. These checkups are usually scheduled ...

  20. Expression of IGF-I and Protein Degradation Markers During Hindlimb Unloading and Growth Hormone Administration in Rats

    NASA Astrophysics Data System (ADS)

    Leinsoo, T. A.; Turtikova, O. V.; Shenkman, B. S.

    2013-02-01

    It is known that hindlimb unloading or spaceflight produce atrophy and a number of phenotypic alterations in skeletal muscles. Many of these processes are triggered by the axis growth hormone/insulin-like growth factor I. However growth hormone (GH) and insulin-like growth factor I (IGF-I) expression relationship in rodent models of gravitational unloading is weakly investigated. We supposed the IGF-I is involved in regulation of protein turnover. In this study we examined the IGF-I expression by RT-PCR assay in the rat soleus, tibialis anterior and liver after 3 day of hindlimb suspension with growth hormone administration. Simultaneously were studied expression levels of MuRF-1 and MAFbx/atrogin as a key markers of intracellular proteolysis. We demonstrated that GH administration did not prevent IGF-I expression decreasing under the conditions of simulated weightlessness. It was concluded there are separate mechanisms of action of GH and IGF-I on protein metabolism in skeletal muscles. Gravitational unloading activate proteolysis independently of growth hormone activity.

  1. Growth chart

    MedlinePlus

    Height and weight chart ... Growth charts are used to compare your child's height, weight, and head size against children of the ... From these numbers, the national average weight and height for each age and gender were established. The ...

  2. Population growth and economic growth.

    PubMed

    Narayana, D L

    1984-01-01

    This discussion of the issues relating to the problem posed by population explosion in the developing countries and economic growth in the contemporary world covers the following: predictions of economic and social trends; the Malthusian theory of population; the classical or stationary theory of population; the medical triage model; ecological disaster; the Global 2000 study; the limits to growth; critiques of the Limits to Growth model; nonrenewable resources; food and agriculture; population explosion and stabilization; space and ocean colonization; and the limits perspective. The Limits to Growth model, a general equilibrium anti-growth model, is the gloomiest economic model ever constructed. None of the doomsday models, the Malthusian theory, the classical stationary state, the neo-Malthusian medical triage model, the Global 2000 study, are so far reaching in their consequences. The course of events that followed the publication of the "Limits to Growth" in 1972 in the form of 2 oil shocks, food shock, pollution shock, and price shock seemed to bear out formally the gloomy predictions of the thesis with a remarkable speed. The 12 years of economic experience and the knowledge of resource trends postulate that even if the economic pressures visualized by the model are at work they are neither far reaching nor so drastic. Appropriate action can solve them. There are several limitations to the Limits to Growth model. The central theme of the model, which is overshoot and collapse, is unlikely to be the course of events. The model is too aggregative to be realistic. It exaggerates the ecological disaster arising out of the exponential growth of population and industry. The gross underestimation of renewable resources is a basic flaw of the model. The most critical weakness of the model is its gross underestimation of the historical trend of technological progress and the technological possiblities within industry and agriculture. The model does correctly emphasize

  3. The aromatase inhibitor letrozole increases epiphyseal growth plate height and tibial length in peripubertal male mice.

    PubMed

    Eshet, R; Maor, G; Ben Ari, T; Ben Eliezer, M; Gat-Yablonski, G; Phillip, M

    2004-07-01

    Sex hormones may influence longitudinal growth, either indirectly, by affecting the growth-hormone-insulin-like growth factor I (IGF-I) axis, or directly, by affecting changes within the epiphyseal growth plate (EGP). The aim of the present study was to investigate the effects of letrozole, an aromatase inhibitor, on longitudinal growth and changes in the EGP in vivo. Eighteen peripubertal male mice were divided into three groups. The first group was killed at baseline, the second was injected with letrozole (Femara) s.c., 2 mg/kg body weight/day, for 10 days, and the third was injected with the vehicle alone. Serum testosterone levels were found to be significantly higher in the treated group than in the controls. Letrozole induced a significant increase in body weight, tail length and serum growth hormone level, but had no significant effect on the level of serum IGF-I. On histomorphometric study, there was a significant increase (12%) in EGP height in the treated animals compared with controls. Immunohistochemistry showed a 3.4-fold letrozole-induced increase in the proliferation of the EGP chondrocytes, as estimated by the number of proliferation cell nuclear antigen-stained cells, and a decrease in the differentiation of the EGP chondrocytes, as estimated by type X collagen staining. Letrozole did not interfere with type II collagen levels. The study group also showed a twofold increase in the number of IGF-I receptor-positive cells compared with controls. In conclusion, the aromatase inhibitor, letrozole, appears to increase the linear growth potential of the EGP in mice. PMID:15225141

  4. Serum concentrations of insulin-like growth factor-I and insulin-like growth factor binding protein-2 and -3 in eight hoofstock species.

    PubMed

    Govoni, Kristen E; Goodman, Danielle; Maclure, Rebecca M; Penfold, Linda M; Zinn, Steven A

    2011-01-01

    The somatotropic axis, which includes growth hormone, insulin-like growth factor (IGF)-I, and IGF binding proteins (IGFBP), is involved in the regulation of growth and metabolism. Measures of the somatotropic axis can be predictive of nutritional status and growth rate that can be utilized to identify nutritional status of individual animals. Before the somatotropic axis can be a predictive tool, concentrations of hormones of the somatotropic axis need to be established in healthy individuals. To begin to establish these data, we quantified IGF-I, IGFBP-2, and IGFBP-3 in males and females of eight threatened hoofstock species at various ages. Opportunistic blood samples were collected from Bos javanicus (Java banteng), Tragelaphus eurycerus isaaci (bongo), Gazella dama ruficollis (addra gazelle), Taurotragus derbianus gigas (giant eland), Kobus megaceros (Nile lechwe), Hippotragus equines cottoni (roan antelope), Ceratotherium simum simum (white rhinoceros), and Elephas maximus (Asian elephant). Serum IGF-I and IGFBPs were determined by radioimmunoassay and ligand blot, respectively. Generally, IGF-I and IGFBP-3 were greater in males, and IGFBP-2 was greater in females. In banteng (P = 0.08) and male Nile lechwe (P < 0.05), IGF-I increased with age, but decreased in rhinoceros (P = 0.07) and female Nile lechwe (P < 0.05). In banteng, IGFBP-3 was greater (P < 0.01) in males. In elephants (P < 0.05) and antelope (P = 0.08), IGFBP-2 were greater in females. Determination of concentrations of hormones in the somatotropic axis in healthy animals makes it possible to develop models that can identify the nutritional status of these threatened hoofstock species. PMID:20853408

  5. Growth hormone/IGF-I and/or resistive exercise maintains myonuclear number in hindlimb unweighted muscles

    NASA Technical Reports Server (NTRS)

    Allen, D. L.; Linderman, J. K.; Roy, R. R.; Grindeland, R. E.; Mukku, V.; Edgerton, V. R.

    1997-01-01

    In the present study of rats, we examined the role, during 2 wk of hindlimb suspension, of growth hormone/insulin-like growth factor I (GH/IGF-I) administration and/or brief bouts of resistance exercise in ameliorating the loss of myonuclei in fibers of the soleus muscle that express type I myosin heavy chain. Hindlimb suspension resulted in a significant decrease in mean soleus wet weight that was attenuated either by exercise alone or by exercise plus GH/IGF-I treatment but was not attenuated by hormonal treatment alone. Both mean myonuclear number and mean fiber cross-sectional area (CSA) of fibers expressing type I myosin heavy chain decreased after 2 wk of suspension compared with control (134 vs. 162 myonuclei/mm and 917 vs. 2,076 micron2, respectively). Neither GH/IGF-I treatment nor exercise alone affected myonuclear number or fiber CSA, but the combination of exercise and growth-factor treatment attenuated the decrease in both variables. A significant correlation was found between mean myonuclear number and mean CSA across all groups. Thus GH/IGF-I administration and brief bouts of muscle loading had an interactive effect in attenuating the loss of myonuclei induced by chronic unloading.

  6. Bisphenol A accumulation in eggs disrupts the endocrine regulation of growth in rainbow trout larvae.

    PubMed

    Birceanu, Oana; Servos, Mark R; Vijayan, Mathilakath M

    2015-04-01

    Bisphenol A (BPA), a monomer used in the production of plastics and epoxy resins, is ubiquitously present in the aquatic environment. BPA is considered a weak estrogen in fish, but the effects of this chemical on early developmental events are far from clear. We tested the hypothesis that BPA accumulation in eggs, mimicking maternal transfer, disrupts growth hormone/insulin-like growth factor (GH/IGF) axis function, leading to defects in larval growth in rainbow trout. Trout oocytes were exposed to 0 (control), 0.3, 3, and 30 μg ml(-1) BPA for 3h, which led to an accumulation of around 0, 1, 4 and 40 ng BPA per egg, respectively. All treatment groups were fertilized with clean milt and reared in clean water for the rest of the experiment. The embryo BPA content declined over time in all groups and was completely eliminated by 42 days post-fertilization (dpf). Hatchlings from BPA accumulated eggs had higher water content and reduced total energy levels prior to first feed. There was an overall reduction in the specific growth rate and food conversion ratio in larvae reared from BPA-laden eggs. BPA accumulation disrupted the mRNA abundance of genes involved in GH/IGF axis function, including GH isoforms and their receptors, IGF-1 and -2 and IGF receptors, in a life stage-dependent manner. Also, there was a temporal disruption in the mRNA levels of thyroid hormone receptors in the larvae raised from BPA-laden eggs. Altogether, BPA accumulation in eggs, mimicking maternal transfer, affects larval growth and the mode of action involves disruption of genes involved in the GH/IGF and thyroid axes function in trout. PMID:25667994

  7. Amino acids and mammary gland development: nutritional implications for milk production and neonatal growth.

    PubMed

    Rezaei, Reza; Wu, Zhenlong; Hou, Yongqing; Bazer, Fuller W; Wu, Guoyao

    2016-01-01

    Milk is synthesized by mammary epithelial cells of lactating mammals. The synthetic capacity of the mammary gland depends largely on the number and efficiency of functional mammary epithelial cells. Structural development of the mammary gland occurs during fetal growth, prepubertal and post-pubertal periods, pregnancy, and lactation under the control of various hormones (particularly estrogen, growth hormone, insulin-like growth factor-I, progesterone, placental lactogen, and prolactin) in a species- and stage-dependent manner. Milk is essential for the growth, development, and health of neonates. Amino acids (AA), present in both free and peptide-bound forms, are the most abundant organic nutrients in the milk of farm animals. Uptake of AA from the arterial blood of the lactating dam is the ultimate source of proteins (primarily β-casein and α-lactalbumin) and bioactive nitrogenous metabolites in milk. Results of recent studies indicate extensive catabolism of branched-chain AA (leucine, isoleucine and valine) and arginine to synthesize glutamate, glutamine, alanine, aspartate, asparagine, proline, and polyamines. The formation of polypeptides from AA is regulated not only by hormones (e.g., prolactin, insulin and glucocorticoids) and the rate of blood flow across the lactating mammary gland, but also by concentrations of AA, lipids, glucose, vitamins and minerals in the maternal plasma, as well as the activation of the mechanistic (mammalian) target rapamycin signaling by certain AA (e.g., arginine, branched-chain AA, and glutamine). Knowledge of AA utilization (including metabolism) by mammary epithelial cells will enhance our fundamental understanding of lactation biology and has important implications for improving the efficiency of livestock production worldwide. PMID:27042295

  8. Hepatic IGF1 DNA methylation is influenced by gender but not by intrauterine growth restriction in the young lamb.

    PubMed

    Carr, D J; Milne, J S; Aitken, R P; Adam, C L; Wallace, J M

    2015-12-01

    Intrauterine growth restriction (IUGR) and postnatal catch-up growth confer an increased risk of adult-onset disease. Overnourishment of adolescent ewes generates IUGR in ∼ 50% of lambs, which subsequently exhibit increased fractional growth rates. We investigated putative epigenetic changes underlying this early postnatal phenotype by quantifying gene-specific methylation at cytosine:guanine (CpG) dinucleotides. Hepatic DNA/RNA was extracted from IUGR [eight male (M)/nine female (F)] and normal birth weight (12 M/9 F) lambs. Polymerase chain reaction was performed using primers targeting CpG islands in 10 genes: insulin, growth hormone, insulin-like growth factor (IGF)1, IGF2, H19, insulin receptor, growth hormone receptor, IGF receptors 1 and 2, and the glucocorticoid receptor. Using pyrosequencing, methylation status was determined by quantifying cytosine:thymine ratios at 57 CpG sites. Messenger RNA (mRNA) expression of IGF system genes and plasma IGF1/insulin were determined. DNA methylation was independent of IUGR status but sexual dimorphism in IGF1 methylation was evident (MF (both P<0.001). IGF1 mRNA expression correlated negatively with IGF1 methylation (r=-0.507, P=0.002) and positively with plasma IGF1 (r=0.884, P<0.001). Carcass and empty body weights were greater in males (P=0.002-0.014) and this gender difference in early body conformation was mirrored by sexual dimorphism in hepatic IGF1 DNA methylation, mRNA expression and plasma IGF1 concentrations. PMID:26310177

  9. Effects of steroid treatment on growth, nutrient partitioning, and expression of genes related to growth and nutrient metabolism in adult triploid rainbow trout (Oncorhynchus mykiss).

    PubMed

    Cleveland, B M; Weber, G M

    2016-07-01

    The contribution of sex steroids to nutrient partitioning and energy balance during gonad development was studied in rainbow trout. Specifically, 19-mo old triploid (3N) female rainbow trout were fed treatment diets supplemented with estradiol-17β (E2), testosterone (T), or dihydrotestosterone at 30-mg steroid/kg diet for a 1-mo period. Growth performance, nutrient partitioning, and expression of genes central to growth and nutrient metabolism were compared with 3N and age-matched diploid (2N) female fish consuming a control diet not supplemented with steroids. Only 2 N fish exhibited active gonad development, with gonad weights increasing from 3.7% to 5.5% of body weight throughout the study, whereas gonad weights in 3N fish remained at 0.03%. Triploid fish consuming dihydrotestosterone exhibited faster specific growth rates than 3N-controls (P < 0.05). Consumption of E2 in 3N fish reduced fillet growth and caused lower fillet yield compared with all other treatment groups (P < 0.05). In contrast, viscera fat gain was not affected by steroid consumption (P > 0.05). Gene transcripts associated with physiological pathways were identified in maturing 2N and E2-treated 3N fish that differed in abundance from 3N-control fish (P < 0.05). In liver these mechanisms included the growth hormone/insulin-like growth factor (IGF) axis (igf1, igf2), IGF binding proteins (igfbp1b1, igfbp2b1, igfbp5b1, igfbp6b1), and genes associated with lipid binding and transport (fabp3, fabp4, lpl, cd36), fatty acid oxidation (cpt1a), and the pparg transcription factor. In muscle, these mechanisms included reductions in myogenic gene expression (fst, myog) and the proteolysis-related gene, cathepsin-L, suggesting an E2-induced reduction in the capacity for muscle growth. These findings suggest that increased E2 signaling in the sexually maturing female rainbow trout alters physiological pathways in liver, particularly those related to IGF signaling and lipid metabolism, to partition

  10. Environmentally Relevant Concentrations of the Flame Retardant Tris(1,3-dichloro-2-propyl) Phosphate Inhibit Growth of Female Zebrafish and Decrease Fecundity.

    PubMed

    Zhu, Ya; Ma, Xufa; Su, Guanyong; Yu, Liqin; Letcher, Robert J; Hou, Jie; Yu, Hongxia; Giesy, John P; Liu, Chunsheng

    2015-12-15

    Bioconcentrations of tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) in brain, gonad, and liver as well as effects on fecundity and development of zebrafish (Danio rerio) were determined. Zebrafish (1-month old) were exposed to environmentally relevant concentrations of 29 ± 2.1, 600 ± 21, or 6300 ± 130 ng TDCIPP/L. After 120 days of exposure, TDCIPP accumulated in the brain, gonad, and liver with bioconcentration factors of 460, 38, and 87 in females and 26, 55, and 110 in males, respectively. TDCIPP accumulated to a greater extent in brains of females than those of males. Exposure to 6300 ± 130 ng TDCIPP/L resulted in significantly (P < 0.05) fewer eggs being produced, but the histology of the gonad, plasma concentrations of estradiol and 11-ketotestosterone, and expression of genes involved in hypothalamic-pituitary-gonadal-liver axis were not significantly (P > 0.05) different between individuals exposed to TDCIPP and the unexposed control fish. Exposure to TDCIPP resulted in shorter body length, lighter body mass, and lower gonadal-somatic index in females. These effects were possibly due to down-regulation of expression of genes along the growth hormone/insulin-like growth factor (GH/IGF) axis. Correlations between the production of eggs and developmental parameters or expression of genes along the GH/IGF axis further suggested that environmentally relevant concentrations of TDCIPP could have adverse effects on reproduction, possibly due to the inhibition of the growth of females. PMID:26512412

  11. Invited review: Growth-promoting effects of colostrum in calves based on interaction with intestinal cell surface receptors and receptor-like transporters.

    PubMed

    Ontsouka, Edgar C; Albrecht, Christiane; Bruckmaier, Rupert M

    2016-06-01

    The postnatal development and maturation of the gastrointestinal (GI) tract of neonatal calves is crucial for their survival. Major morphological and functional changes in the calf's GI tract initiated by colostrum bioactive substances promote the establishment of intestinal digestion and absorption of food. It is generally accepted that colostrum intake provokes the maturation of organs and systems in young calves, illustrating the significance of the cow-to-calf connection at birth. These postnatal adaptive changes of the GI tissues in neonatal calves are especially induced by the action of bioactive substances such as insulin-like growth factors, hormones, or cholesterol carriers abundantly present in colostrum. These substances interact with specific cell-surface receptors or receptor-like transporters expressed in the GI wall of neonatal calves to elicit their biological effects. Therefore, the abundance and activity of cell surface receptors and receptor-like transporters binding colostral bioactive substances are a key aspect determining the effects of the cow-to-calf connection at birth. The present review compiles the information describing the effects of colostrum feeding on selected serum metabolic and endocrine traits in neonatal calves. In this context, the current paper discusses specifically the consequences of colostrum feeding on the GI expression and activity of cell-receptors and receptor-like transporters binding growth hormone, insulin-like growth factors, insulin, or cholesterol acceptors in neonatal calves. PMID:26874414

  12. Measuring Growth with the Posttraumatic Growth Inventory

    ERIC Educational Resources Information Center

    Anderson, Walter P., Jr.; Lopez-Baez, Sandra I.

    2008-01-01

    The Posttraumatic Growth Inventory (PTGI; R. G. Tedeschi & L. G. Calhoun, 1996) was used to measure the growth of university students (N = 347). Results were compared with those of trauma studies and indicate that the PTGI is a general measure of growth suitable for future nontrauma studies. Results reflect a minimal relationship between…

  13. Mycobacterium leprae-induced Insulin-like Growth Factor I attenuates antimicrobial mechanisms, promoting bacterial survival in macrophages.

    PubMed

    Batista-Silva, L R; Rodrigues, Luciana Silva; Vivarini, Aislan de Carvalho; Costa, Fabrício da Mota Ramalho; Mattos, Katherine Antunes de; Costa, Maria Renata Sales Nogueira; Rosa, Patricia Sammarco; Toledo-Pinto, T G; Dias, André Alves; Moura, Danielle Fonseca; Sarno, Euzenir Nunes; Lopes, Ulisses Gazos; Pessolani, Maria Cristina Vidal

    2016-01-01

    Mycobacterium leprae (ML), the etiologic agent of leprosy, can subvert macrophage antimicrobial activity by mechanisms that remain only partially understood. In the present study, the participation of hormone insulin-like growth factor I (IGF-I) in this phenomenum was investigated. Macrophages from the dermal lesions of the disseminated multibacillary lepromatous form (LL) of leprosy expressed higher levels of IGF-I than those from the self-limited paucibacillary tuberculoid form (BT). Higher levels of IGF-I secretion by ML-infected macrophages were confirmed in ex vivo and in vitro studies. Of note, the dampening of IGF-I signaling reverted the capacity of ML-infected human and murine macrophages to produce antimicrobial molecules and promoted bacterial killing. Moreover, IGF-I was shown to inhibit the JAK/STAT1-dependent signaling pathways triggered by both mycobacteria and IFN-γ most probably through its capacity to induce the suppressor of cytokine signaling-3 (SOCS3). Finally, these in vitro findings were corroborated by in vivo observations in which higher SOCS3 expression and lower phosphorylation of STAT1 levels were found in LL versus BT dermal lesions. Altogether, our data strongly suggest that IGF-I contributes to the maintenance of a functional program in infected macrophages that suits ML persistence in the host, reinforcing a key role for IGF-I in leprosy pathogenesis. PMID:27282338

  14. Mycobacterium leprae-induced Insulin-like Growth Factor I attenuates antimicrobial mechanisms, promoting bacterial survival in macrophages

    PubMed Central

    Batista-Silva, L. R.; Rodrigues, Luciana Silva; Vivarini, Aislan de Carvalho; Costa, Fabrício da Mota Ramalho; Mattos, Katherine Antunes de; Costa, Maria Renata Sales Nogueira; Rosa, Patricia Sammarco; Toledo-Pinto, T. G.; Dias, André Alves; Moura, Danielle Fonseca; Sarno, Euzenir Nunes; Lopes, Ulisses Gazos; Pessolani, Maria Cristina Vidal

    2016-01-01

    Mycobacterium leprae (ML), the etiologic agent of leprosy, can subvert macrophage antimicrobial activity by mechanisms that remain only partially understood. In the present study, the participation of hormone insulin-like growth factor I (IGF-I) in this phenomenum was investigated. Macrophages from the dermal lesions of the disseminated multibacillary lepromatous form (LL) of leprosy expressed higher levels of IGF-I than those from the self-limited paucibacillary tuberculoid form (BT). Higher levels of IGF-I secretion by ML-infected macrophages were confirmed in ex vivo and in vitro studies. Of note, the dampening of IGF-I signaling reverted the capacity of ML-infected human and murine macrophages to produce antimicrobial molecules and promoted bacterial killing. Moreover, IGF-I was shown to inhibit the JAK/STAT1-dependent signaling pathways triggered by both mycobacteria and IFN-γ most probably through its capacity to induce the suppressor of cytokine signaling-3 (SOCS3). Finally, these in vitro findings were corroborated by in vivo observations in which higher SOCS3 expression and lower phosphorylation of STAT1 levels were found in LL versus BT dermal lesions. Altogether, our data strongly suggest that IGF-I contributes to the maintenance of a functional program in infected macrophages that suits ML persistence in the host, reinforcing a key role for IGF-I in leprosy pathogenesis. PMID:27282338

  15. Growth hormone test

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/003706.htm Growth hormone test To use the sharing features on this page, please enable JavaScript. The growth hormone test measures the amount of growth hormone in ...

  16. Growth hormone suppression test

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/003376.htm Growth hormone suppression test To use the sharing features on this page, please enable JavaScript. The growth hormone suppression test determines whether growth hormone production is ...

  17. Growth hormone suppression test

    MedlinePlus

    The growth hormone suppression test determines whether growth hormone production is being suppressed by high blood sugar. ... away. The lab measures the glucose and growth hormone (GH) levels in each sample.

  18. Simulating Population Growth.

    ERIC Educational Resources Information Center

    Byington, Scott

    1997-01-01

    Presents a strategy to help students grasp the important implications of population growth. Involves an interactive demonstration that allows students to experience exponential and logistic population growth followed by a discussion of the implications of population-growth principles. (JRH)

  19. Influence of insulin-like growth factor-binding proteins-2 and -3 in the pathogenesis of cystic ovarian disease in cattle.

    PubMed

    Rodríguez, Fernanda M; Salvetti, Natalia R; Panzani, Carolina G; Barbeito, Claudio G; Ortega, Hugo H; Rey, Florencia

    2011-10-01

    Ovarian cysts are one of the major causes of infertility in dairy cows. The development is associated with an endocrine imbalance in the hypothalamo-hypophyseal-gonadal axis in which endocrine factors participate in follicular growth and differentiation and in the secretion of ovarian hormones. Insulin-like growth factor family are essential local regulators of ovarian follicle development and functionality and actions are mediated by binding protein activity. The aim of the present study was to analyze the expression of IGFBP-2 and IGFBP-3 in developing follicles of normal estrous cycling animals and with spontaneous and induced cystic ovarian disease (COD) to determine IGF bioavailability. The mRNA of IGFBP-2 and IGFBP-3 in follicular walls was quantified by reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization. Protein expression was analyzed by immunohistochemistry. The results demonstrated reduced amounts of mRNA of both IGFBPs in the granulosa cells of ovarian follicles of animals with COD (P<0.05). The present study suggests that the IGF system or imbalances between IGFs and IGFBPs may be involved in COD of cattle. PMID:21940120

  20. Do Student Growth Scores Measure Academic Growth?

    ERIC Educational Resources Information Center

    Pomplun, Mark R.

    2009-01-01

    This study investigated convergent validity evidence for student growth scores with high school course grades. The Measures of Academic Progress and Educational Planning and Assessment System growth scores for approximately 1,800 ninth-grade students over 2 years were related to language, arts, and mathematics course grades for developmental,…

  1. Growth hormone deficiency - children

    MedlinePlus

    ... the same age. The child will have normal intelligence in most cases. In older children, puberty may ... hormones cause the body to make. Tests can measure these growth factors. Accurate growth hormone deficiency testing ...

  2. The growth of birdwings

    NASA Technical Reports Server (NTRS)

    Meunier, K.

    1980-01-01

    Growth and order allometry is defined and applied to the growth of bird effects of negative wing allometry discussed with regard to body size and flight power. Transposition and evolutionary significance are explained.

  3. [Population Growth and Development].

    ERIC Educational Resources Information Center

    Clausen, A. W.

    Rapid population growth as a central development problem, the proper domain of government in reducing population growth, and effective measures which can be taken to reduce fertility are examined. Rapid population growth puts a brake on development because it exacerbates the difficult choice between higher consumption now and the investment needed…

  4. Prepubertal Exposure to Arsenic(III) Suppresses Circulating Insulin-like Growth Factor-1 (IGF-1) Delaying Sexual Maturation in Female Rats

    PubMed Central

    Reilly, Michael P.; Saca, James C.; Hamilton, Alina; Solano, Rene F.; Rivera, Jesse R.; Whitehouse-Innis, Wendy; Parsons, Jason G.; Dearth, Robert K.

    2013-01-01

    Arsenic (As) is a prevalent environmental toxin; readily accessible for human consumption and has been identified as an endocrine disruptor. However, it is not known what impact As has on female sexual maturation. Therefore, in the present study, we investigated the effects of prepubertal exposure on mammary gland development and pubertal onset in female rats. Results showed that prepubertal exposure to 10mg/kg of arsenite (As(III)) delayed vaginal opening (VO) and prepubertal mammary gland maturation. We determined that As accumulates in the liver, disrupts hepatocyte function and suppresses serum levels of the puberty related hormone insulin-like growth factor 1 (IGF-1) in prepubertal animals. Overall, this is the first study to show that prepubertal exposure to As(III) acts peripherally to suppresses circulating levels of IGF-1 resulting in delayed sexual maturation. Furthermore, this study identifies a critical window of increased susceptibility to As(III) that may have a lasting impact on female reproductive function. PMID:24090629

  5. Growth hormone, growth factors, and acromegaly

    SciTech Connect

    Ludecke, D.K.; Tolis, G.T.

    1987-01-01

    This book contains five sections, each consisting of several papers. The section headings are: Biochemistry and Physiology of GH and Growth Factors, Pathology of Acromegaly, Clinical Endocrinology of Acromegaly, Nonsurgical Therapy of Acromegaly, and Surgical Therapy of Acromegaly.

  6. Human growth hormone.

    PubMed

    Strobl, J S; Thomas, M J

    1994-03-01

    The study of human growth hormone is a little more than 100 years old. Growth hormone, first identified for its dramatic effect on longitudinal growth, is now known to exert generalized effects on protein, lipid, and carbohydrate metabolism. Additional roles for growth hormone in human physiology are likely to be discovered in the areas of sleep research and reproduction. Furthermore, there is some indication that growth hormone also may be involved in the regulation of immune function, mental well-being, and the aging process. Recombinant DNA technology has provided an abundant and safe, albeit expensive, supply of human growth hormone for human use, but the pharmacological properties of growth hormone are poor. Most growth hormone-deficient individuals exhibit a secretory defect rather than a primary defect in growth hormone production, however, and advances in our understanding of the neuroendocrine regulation of growth hormone secretion have established the basis for the use of drugs to stimulate release of endogenously synthesized growth hormone. This promises to be an important area for future drug development. PMID:8190748

  7. Maintenance of myonuclear domain size in rat soleus after overload and growth hormone/IGF-I treatment

    NASA Technical Reports Server (NTRS)

    McCall, G. E.; Allen, D. L.; Linderman, J. K.; Grindeland, R. E.; Roy, R. R.; Mukku, V. R.; Edgerton, V. R.

    1998-01-01

    The purpose of this study was to determine the effects of functional overload (FO) combined with growth hormone/insulin-like growth factor I (GH/IGF-I) administration on myonuclear number and domain size in rat soleus muscle fibers. Adult female rats underwent bilateral ablation of the plantaris and gastrocnemius muscles and, after 7 days of recovery, were injected three times daily for 14 days with GH/IGF-I (1 mg/kg each; FO + GH/IGF-I group) or saline vehicle (FO group). Intact rats receiving saline vehicle served as controls (Con group). Muscle wet weight was 32% greater in the FO than in the Con group: 162 +/- 8 vs. 123 +/- 16 mg. Muscle weight in the FO + GH/IGF-I group (196 +/- 14 mg) was 59 and 21% larger than in the Con and FO groups, respectively. Mean soleus fiber cross-sectional area of the FO + GH/IGF-I group (2,826 +/- 445 microm2) was increased compared with the Con (2,044 +/- 108 microm2) and FO (2,267 +/- 301 microm2) groups. The difference in fiber size between the FO and Con groups was not significant. Mean myonuclear number increased in FO (187 +/- 15 myonuclei/mm) and FO + GH/IGF-I (217 +/- 23 myonuclei/mm) rats compared with Con (155 +/- 12 myonuclei/mm) rats, although the difference between FO and FO + GH/IGF-I animals was not significant. The mean cytoplasmic volume per myonucleus (myonuclear domain) was similar across groups. These results demonstrate that the larger mean muscle weight and fiber cross-sectional area occurred when FO was combined with GH/IGF-I administration and that myonuclear number increased concomitantly with fiber volume. Thus there appears to be some mechanism(s) that maintains the myonuclear domain when a fiber hypertrophies.

  8. Growth rates made easy.

    PubMed

    Hall, Barry G; Acar, Hande; Nandipati, Anna; Barlow, Miriam

    2014-01-01

    In the 1960s-1980s, determination of bacterial growth rates was an important tool in microbial genetics, biochemistry, molecular biology, and microbial physiology. The exciting technical developments of the 1990s and the 2000s eclipsed that tool; as a result, many investigators today lack experience with growth rate measurements. Recently, investigators in a number of areas have started to use measurements of bacterial growth rates for a variety of purposes. Those measurements have been greatly facilitated by the availability of microwell plate readers that permit the simultaneous measurements on up to 384 different cultures. Only the exponential (logarithmic) portions of the resulting growth curves are useful for determining growth rates, and manual determination of that portion and calculation of growth rates can be tedious for high-throughput purposes. Here, we introduce the program GrowthRates that uses plate reader output files to automatically determine the exponential portion of the curve and to automatically calculate the growth rate, the maximum culture density, and the duration of the growth lag phase. GrowthRates is freely available for Macintosh, Windows, and Linux. We discuss the effects of culture volume, the classical bacterial growth curve, and the differences between determinations in rich media and minimal (mineral salts) media. This protocol covers calibration of the plate reader, growth of culture inocula for both rich and minimal media, and experimental setup. As a guide to reliability, we report typical day-to-day variation in growth rates and variation within experiments with respect to position of wells within the plates. PMID:24170494

  9. Elevated temperature crack growth

    NASA Technical Reports Server (NTRS)

    Kim, K. S.; Vanstone, R. H.

    1992-01-01

    The purpose of this program was to extend the work performed in the base program (CR 182247) into the regime of time-dependent crack growth under isothermal and thermal mechanical fatigue (TMF) loading, where creep deformation also influences the crack growth behavior. The investigation was performed in a two-year, six-task, combined experimental and analytical program. The path-independent integrals for application to time-dependent crack growth were critically reviewed. The crack growth was simulated using a finite element method. The path-independent integrals were computed from the results of finite-element analyses. The ability of these integrals to correlate experimental crack growth data were evaluated under various loading and temperature conditions. The results indicate that some of these integrals are viable parameters for crack growth prediction at elevated temperatures.

  10. Growth of platinum nanocrystals

    SciTech Connect

    2009-01-01

    Movie showing the growth of platinum nanocrystals in a liquid cell observed in situ using the JEOL 3010 TEM at the National Center for Electron Microscopy. This is the first ever-real time movie showing nucleation and growth by monomer attachment or by smaller nanocrystals coalescing to form larger nanocrystals. All the nanocrystals end up being roughly the same shape and size. http://newscenter.lbl.gov/feature-stories/2009/08/04/growth-spurts/

  11. Mercury iodide crystal growth

    NASA Technical Reports Server (NTRS)

    Cadoret, R.

    1982-01-01

    The purpose of the Mercury Iodide Crystal Growth (MICG) experiment is the growth of near-perfect single crystals of mercury Iodide (HgI2) in a microgravity environment which will decrease the convection effects on crystal growth. Evaporation and condensation are the only transformations involved in this experiment. To accomplish these objectives, a two-zone furnace will be used in which two sensors collect the temperature data (one in each zone).

  12. Differential flank growth

    NASA Astrophysics Data System (ADS)

    Zieschang, H. E.; Sievers, A.

    1994-08-01

    With the mathematical basis for the precise analysis of developmental processes in plants, the patterns of growth in phototropic and gravitropic responses have become better understood. A detailed temporal and spatial quantification of a growth process is an important tool for evaluating hypotheses about the underlying physiological mechanisms. Studies of growth rates and curvature show that the original Cholodny-Went hypothesis cannot explain the complex growth patterns during tropic responses of shoots and roots. In addition, regulating factors other than the lateral redistribution of hormones must be taken into account. Electrophysiological studies on roots led to a modification of the Cholodny-Went hypothesis in that redistributions of bioelectrical activities are observed.

  13. Leaf growth is conformal.

    PubMed

    Alim, Karen; Armon, Shahaf; Shraiman, Boris I; Boudaoud, Arezki

    2016-01-01

    Growth pattern dynamics lie at the heart of morphogenesis. Here, we investigate the growth of plant leaves. We compute the conformal transformation that maps the contour of a leaf at a given stage onto the contour of the same leaf at a later stage. Based on the mapping we predict the local displacement field in the leaf blade and find it to agree with the experimentally measured displacement field to 92%. This approach is applicable to any two-dimensional system with locally isotropic growth, enabling the deduction of the whole growth field just from observation of the tissue contour. PMID:27597439

  14. Growth and growth hormone: An overview.

    PubMed

    Teran, Enrique; Chesner, Jaclyn; Rapaport, Robert

    2016-06-01

    Growth is a good indicator of a child's health. Growth disturbances, including short stature or growth failure, could be indications of illnesses such as chronic disease, nutritional deficits, celiac disease or hormonal abnormalities. Therefore, a careful assessment of the various requirements for normal growth needs to be done by history, physical examination, and screening laboratory tests. More details will be reviewed about the GH-IGF axis, its abnormalities with special emphasis on GH deficiency, its diagnosis and treatment. GH treatment indications in the US will be reviewed and a few only will be highlighted. They will include GH deficiency, as well as the treatment of children born SGA, including the results of a US study using FDA approved dose of 0.48mg/kg/week. GH deficiency in adults will also be briefly reviewed. Treatment of patients with SHOX deficiency will also be discussed. Possible side effects of GH treatment and the importance of monitoring safety will be highlighted. PMID:26936284

  15. Hail Growth Hysteresis.

    NASA Astrophysics Data System (ADS)

    Johnson, David B.; Rasmussen, Roy M.

    1992-12-01

    The transition between wet and dry growth for graupel and hail is examined, and new figures are presented illustrating the critical water contents necessary for transitions into or out of the wet-growth regime. These figures are extended to smaller sizes and lower bulk densities than considered in previous studies. In addition, the possibility of hysteresis in the transitions is examined.

  16. Impact of Population Growth

    ERIC Educational Resources Information Center

    Ehrlich, Paul R.; Holdren, John P.

    1971-01-01

    Discusses the interrelated crises in population growth, natural resources, and environmental quality. Major problems include population control, redirection of technology, closed resource cycles, equitable opportunity distribution and prosperity. Population growth is regarded as causing a disportionate world-wide negative environmental impact.…

  17. Spiritual Growth and Development.

    ERIC Educational Resources Information Center

    Wakefield, Dara V.

    Spiritual living demands growth, and spiritual development has many parallels with human development. Ministers who are knowledgeable of the various stages are best prepared to assist and optimize spiritual growth. The primary benefit of nurturing believers through developmental stages is assured spiritual health and maturity in the context of a…

  18. Modeling Exponential Population Growth

    ERIC Educational Resources Information Center

    McCormick, Bonnie

    2009-01-01

    The concept of population growth patterns is a key component of understanding evolution by natural selection and population dynamics in ecosystems. The National Science Education Standards (NSES) include standards related to population growth in sections on biological evolution, interdependence of organisms, and science in personal and social…

  19. Vicarious Occupational Posttraumatic Growth

    ERIC Educational Resources Information Center

    Moran, Larry

    2012-01-01

    Traditional studies of posttraumatic growth center on the individual or close family members as they deal with traumatic events. The current study examines workers who experience posttraumatic growth when a coworker has a traumatic experience. The participants in this study were firefighters in suburban Cook County, Illinois. Participants were…

  20. Growth regulation of cancer

    SciTech Connect

    Lippman, M.E. )

    1988-01-01

    This book contains proceedings of an Ortho-UCLA Symposium on growth regulation of cancer. Included are the following chapters: Swiss 3T3 mouse embryo fibroblasts transfected with a human Prepro-GRP gene synthesize and secrete Pro-GRP rather than GRP, proto-oncogenes as mediators of growth and development: discussion summary, animal studies and clinical trials.

  1. Microgravity Plant Growth Demonstration

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Two visitors watch a TV monitor showing plant growth inside a growth chamber designed for operation aboard the Space Shuttle as part of NASA's Space Product Development program. The exhibit, featuring work by the Wisconsin Center for Space Automation and Robotics, was at AirVenture 2000 sponsored by the Experimental Aircraft Association in Oshkosh, WI.

  2. Plant Growth Regulators.

    ERIC Educational Resources Information Center

    Nickell, Louis G.

    1978-01-01

    Describes the effect of "plant growth regulators" on plants, such as controlling the flowering, fruit development, plant size, and increasing crop yields. Provides a list of plant growth regulators which includes their chemical, common, and trade names, as well as their different use(s). (GA)

  3. Growth Hormone Promotes Lymphangiogenesis

    PubMed Central

    Banziger-Tobler, Nadja Erika; Halin, Cornelia; Kajiya, Kentaro; Detmar, Michael

    2008-01-01

    The lymphatic system plays an important role in inflammation and cancer progression, although the molecular mechanisms involved are poorly understood. As determined using comparative transcriptional profiling studies of cultured lymphatic endothelial cells versus blood vascular endothelial cells, growth hormone receptor was expressed at much higher levels in lymphatic endothelial cells than in blood vascular endothelial cells. These findings were confirmed by quantitative real-time reverse transcriptase-polymerase chain reaction and Western blot analyses. Growth hormone induced in vitro proliferation, sprouting, tube formation, and migration of lymphatic endothelial cells, and the mitogenic effect was independent of vascular endothelial growth factor receptor-2 or -3 activation. Growth hormone also inhibited serum starvation-induced lymphatic endothelial cell apoptosis. No major alterations of lymphatic vessels were detected in the normal skin of bovine growth hormone-transgenic mice. However, transgenic delivery of growth hormone accelerated lymphatic vessel ingrowth into the granulation tissue of full-thickness skin wounds, and intradermal delivery of growth hormone resulted in enlargement and enhanced proliferation of cutaneous lymphatic vessels in wild-type mice. These results identify growth hormone as a novel lymphangiogenic factor. PMID:18583315

  4. Growth and inequality

    NASA Astrophysics Data System (ADS)

    Eliazar, Iddo

    2015-11-01

    How are growth and inequality related? Evidently, this question is of prime importance in the social sciences, as socioeconomic inequality is one of the major forces shaping the course of human history. Moreover, this question is of importance also in the physical sciences, as the notion of socioeconomic inequality can be applied to analyze physical growth. In this paper we consider general growth processes whose dynamics are governed by ordinary differential equations, and present a comprehensive inequality-based socioeconophysical study of their evolutions. From a social-sciences perspective, the results established describe the inequality that will be generated by different types of economic growth. From a physical-sciences perspective, the results established provide a socioeconomic classification of growth processes.

  5. Growth factors for nanobacteria

    NASA Astrophysics Data System (ADS)

    Ciftcioglu, Neva; Kajander, E. Olavi

    1999-12-01

    Nanobacteria are novel microorganisms recently isolated from fetal bovine serum and blood of cows and humans. These coccoid, gram negative bacteria in alpha-2 subgroup of Proteobacteria grow slowly under mammalian cell culture conditions but not in common media for microbes. Now we have found two different kinds of culture supplement preparations that improve their growth and make them culturable in the classical sense. These are supernatant fractions of conditioned media obtained from 1 - 3 months old nanobacteria cultures and from about a 2 weeks old Bacillus species culture. Both improved multiplication and particle yields and the latter increased their resistance to gentamicin. Nanobacteria cultured with any of the methods shared similar immunological property, structure and protein pattern. The growth supporting factors were heat-stabile and nondialyzable, and dialysis improved the growth promoting action. Nanobacteria formed stony colonies in a bacteriological medium supplemented with the growth factors. This is an implication that nanobacterial growth is influenced by pre-existing bacterial flora.

  6. On Dinosaur Growth

    NASA Astrophysics Data System (ADS)

    Erickson, Gregory M.

    2014-05-01

    Despite nearly two centuries of investigation, a comprehensive understanding of dinosaur biology has proven intractable. The recent development of means to study tissue-level growth, age these animals, and make growth curves has revolutionized our knowledge of dinosaur lives. From such data it is now understood that dinosaurs grew both disruptively and determinately; that they rarely if ever exceeded a century in age; that they became giants through accelerated growth and dwarfed through truncated development; that they were likely endothermic, sexually matured like crocodiles, and showed survivorship like populations of large mammals; and that basal birds retained dinosaurian physiology.

  7. Insulin-like growth factor I (IGF-I) in a growth-enhanced transgenic (GH-overexpressing) bony fish, the tilapia (Oreochromis niloticus): indication for a higher impact of autocrine/paracrine than of endocrine IGF-I.

    PubMed

    Eppler, Elisabeth; Caelers, Antje; Shved, Natallia; Hwang, Guylin; Rahman, Azizur M; Maclean, Norman; Zapf, Jürgen; Reinecke, Manfred

    2007-08-01

    Several lines of growth hormone (GH)-overexpressing fish have been produced and analysed for growth and fertility parameters. However, only few data are available on the growth-promoting hormone insulin-like growth factor I (IGF-I) that mediates most effects of GH, and these are contradictory. Using quantitative real-time RT-PCR, radioimmunoassay, in situ hybridization, immunohistochemistry, and radiochromatography we investigated IGF-I and IGF binding proteins (IGFBPs) in an adult (17 months old) transgenic (GH-overexpressing) tilapia (Oreochromis niloticus). The transgenics showed an around 1.5-fold increase in length and an approximately 2.3-fold higher weight than the non-transgenics. Using radioimmunoassay, the serum IGF-I levels were lower (6.22 +/- 0.75 ng/ml) in transgenic than in wild-type (15.01 +/- 1.49 ng/ml) individuals (P = 0.0012). Radioimmunoassayable IGF-I in transgenic liver was 4.2-times higher than in wild-type (16.0 +/- 2.21 vs. 3.83 +/- 0.71 ng/g, P = 0.0017). No hepatocytes in wild-type but numerous hepatocytes in transgenic liver contained IGF-I-immunoreactivity. RT-PCR revealed a 1.4-times higher IGF-I mRNA expression in the liver of the transgenics (10.51 +/- 0.82 vs. 7.3 +/- 0.49 pg/microg total RNA, P = 0.0032). In correspondence, in situ hybridization showed more IGF-I mRNA containing hepatocytes in the transgenics. A twofold elevated IGF-I mRNA expression was determined in the skeletal muscle of transgenics (0.33 +/- 0.02 vs. 0.16 +/- 0.01 pg/microg total RNA, P < 0.0001). Both liver and serum of transgenics showed increased IGF-I binding. The increased IGFBP content in the liver may lead to retention of IGF-I, and/or the release of IGF-I into the circulation may be slower resulting in accumulation of IGF-I in the hepatocytes. Our results indicate that the enhanced growth of the transgenics likely is due to enhanced autocrine/paracrine action of IGF-I in extrahepatic sites, as shown here for skeletal muscle. PMID:17431805

  8. Importance of characterizing growth trajectories

    PubMed Central

    Regnault, Nolwenn; Gillman, Matthew W

    2016-01-01

    In the era of the obesity epidemic in children, characterizing childhood growth trajectories (weight, height or BMI/ weight-for-length) is becoming essential for surveillance. Clinicians routinely use growth curves to identify abnormal growth trajectories. Clinical epidemiologists use growth trajectories for different purposes. They are interested in the determinants of growth but also in the consequences of certain patterns of growth on later health and diseases. Characterizing growth trajectories is also necessary if one wants to predict future growth based on past growth and might be useful in the future to compare the anticipated impact of various interventions. PMID:25413648

  9. Growth of dopamine crystals

    NASA Astrophysics Data System (ADS)

    Patil, Vidya; Patki, Mugdha

    2016-05-01

    Many nonlinear optical (NLO) crystals have been identified as potential candidates in optical and electro-optical devices. Use of NLO organic crystals is expected in photonic applications. Hence organic nonlinear optical materials have been intensely investigated due to their potentially high nonlinearities, and rapid response in electro-optic effect compared to inorganic NLO materials. There are many methods to grow organic crystals such as vapor growth method, melt growth method and solution growth method. Out of these methods, solution growth method is useful in providing constraint free crystal. Single crystals of Dopamine have been grown by evaporating the solvents from aqueous solution. Crystals obtained were of the size of orders of mm. The crystal structure of dopamine was determined using XRD technique. Images of crystals were obtained using FEG SEM Quanta Series under high vacuum and low KV.

  10. Normal growth and development

    MedlinePlus

    ... DIET Poor nutrition can cause problems with a child's intellectual development. A child with a poor diet may be ... care provider if you have concerns about your child's growth and development. Related topics include: Developmental milestones record - 4 months ...

  11. Noise in Exponential Growth

    NASA Astrophysics Data System (ADS)

    Iyer-Biswas, Srividya; Wright, Charles; Henry, Jon; Burov, Stas; Lin, Yihan; Crosson, Sean; Dinner, Aaron; Scherer, Norbert

    2013-03-01

    The interplay between growth and division of cells is has been studied in the context of exponential growth of bacterial cells (in suitable conditions) for decades. However, bulk culture studies obscure phenomena that manifest in single cells over many generations. We introduce a unique technology combining microfluidics, single-cell imaging, and quantitative analysis. This enables us to track the growth of single Caulobacter crescentus stalked cells over hundreds of generations. The statistics that we extract indicate a size thresholding mechanism for cell division and a non-trivial scaling collapse of division time distributions at different temperatures. In this talk I shall discuss these observations and a stochastic model of growth and division that captures all our observations with no free parameters.

  12. Growth hormone deficiency - children

    MedlinePlus

    ... gender. The child will still have normal body proportions, but may be chubby. The child's face often ... A physical exam, including weight, height, and body proportions, will show signs of slowed growth. The child ...

  13. Cellular growth in biofilms

    SciTech Connect

    Wood, B.D.; Whitaker, S.

    1999-09-20

    In this paper the authors develop a macroscopic evolutionary equation for the growth of the cellular phase starting from a microscopic description of mass transport and a simple structured model for product formation. The methods of continuum mechanics and volume averaging are used to develop the macroscopic representation by carefully considering the fluxes of chemical species that pertain to cell growth. The concept of structured models is extended to include the transport of reacting chemical species at the microscopic scale. The resulting macroscopic growth model is similar in form to previously published models for the transport of a single substrate and electron donor and for the production of cellular mass and exopolymer. The method of volume averaging indicated under what conditions the developed growth model is valid and provides an explicit connection between the relevant microscopic model parameters and their corresponding macroscopic counterparts.

  14. Planar elliptic growth

    SciTech Connect

    Mineev, Mark

    2008-01-01

    The planar elliptic extension of the Laplacian growth is, after a proper parametrization, given in a form of a solution to the equation for areapreserving diffeomorphisms. The infinite set of conservation laws associated with such elliptic growth is interpreted in terms of potential theory, and the relations between two major forms of the elliptic growth are analyzed. The constants of integration for closed form solutions are identified as the singularities of the Schwarz function, which are located both inside and outside the moving contour. Well-posedness of the recovery of the elliptic operator governing the process from the continuum of interfaces parametrized by time is addressed and two examples of exact solutions of elliptic growth are presented.

  15. ECOSYSTEM GROWTH AND DEVELOPMENT

    EPA Science Inventory

    Thermodynamically, ecosystem growth and development is the process by which energy throughflow and stored biomass increase. Several proposed hypotheses describe the natural tendencies that occur as an ecosystem matures, and here, we consider five: minimum entropy production, maxi...

  16. Modeling tin whisker growth.

    SciTech Connect

    Weinberger, Christopher Robert

    2013-08-01

    Tin, lead, and lead-tin solders are the most commonly used solders due to their low melting temperatures. However, due to the toxicity problems, lead must now be removed from solder materials. This has lead to the re-emergence of the issue of tin whisker growth. Tin whiskers are a microelectronic packaging issue because they can lead to shorts if they grow to sufficient length. However, the cause of tin whisker growth is still not well understood and there is lack of robust methods to determine when and if whiskering will be a problem. This report summarizes some of the leading theories on whisker growth and attempts to provide some ideas towards establishing the role microstructure plays in whisker growth.

  17. Crack-growth analysis

    NASA Technical Reports Server (NTRS)

    Bianca, C.; Creager, M.

    1976-01-01

    Flexible, adaptable, integrative routine, computer program incorporates Collipriest-Ehret and Paris-Forman equations. Calculates growth from initial defect size and terminates calculation when crack is sufficiently large for critical condition. Wheeler, Willenborg, and Grumman Closure models are available.

  18. Growth hormone stimulation test

    MedlinePlus

    The growth hormone (GH) stimulation test measures the ability of the body to produce GH. ... killing medicine (antiseptic). The first sample is drawn early in the morning. Medicine is given through the ...

  19. Growth outcome: nutritionist perspective.

    PubMed

    Agostoni, Carlo; Fattore, Giovanni

    2013-01-01

    Increasing evidence points to a fundamental role of early nutrition on rates of growth and development, and later health. We may identify three major fields of scientific interest and clinical application. (1) In developing countries poor growth is associated with greater risk of morbidity and mortality from infectious diseases, mainly lower respiratory infections and diarrhea. In these settings, failure to promote compensatory growth may have negative short-term consequences, and the nutritionist's task is the primary prevention of nutrient deficiencies to promote the full expression of the individual genetic potential, while allowing for recovery of early secondary functional deficiencies. (2) A second challenge for nutritionists is represented by the approach to growth impairments in rare disorders, ranging from congenital disorders to chronic infections. Most disorders are favorably influenced by improved nutritional status and better growth, and patients may satisfactorily reach adolescence, pubertal and reproductive age, up to ageing. Even for the less positive conditions, an improvement in the quality of life for families is in any case a rewarding aim. (3) A third challenge is represented by the definition of the role of nutrition on growth in physiological conditions for all individuals. Concern has been raised about the potential adverse long-term consequences of accelerated child growth rates, possibly resulting in a predisposition to develop non-communicable chronic diseases in the adult age. Accordingly, this hypothesis might explain the benefits of breastfeeding in terms of slower early growth, and the fetal origins hypothesis in terms of adverse postnatal catch-up growth in infants born small. Therefore, growth as viewed by a pediatric nutritionist perspective is a complex matter, ranging from the early stages of intrauterine development up to adult ages and ageing processes. Cost/benefit analyses of interventions on growth such as cost per DALYs

  20. Creating new growth platforms.

    PubMed

    Laurie, Donald L; Doz, Yves L; Sheer, Claude P

    2006-05-01

    Sooner or later, most companies can't attain the growth rates expected by their boards and CEOs and demanded by investors. To some extent, such businesses are victims of their own successes. Many were able to sustain high growth rates for a long time because they were in high-growth industries. But once those industries slowed down, the businesses could no longer deliver the performance that investors had come to take for granted. Often, companies have resorted to acquisition, though this strategy has a discouraging track record. Over time, 65% of acquisitions destroy more value than they create. So where does real growth come from? For the past 12 years, the authors have been researching and advising companies on this issue. With the support of researchers at Harvard Business School and Insead, they instituted a project titled "The CEO Agenda and Growth". They identified and approached 24 companies that had achieved significant organic growth and interviewed their CEOs, chief strategists, heads of R&D, CFOs, and top-line managers. They asked, "Where does your growth come from?" and found a consistent pattern in the answers. All the businesses grew by creating new growth platforms (NGPs) on which they could build families of products and services and extend their capabilities into multiple new domains. Identifying NGP opportunities calls for executives to challenge conventional wisdom. In all the companies studied, top management believed that NGP innovation differed significantly from traditional product or service innovation. They had independent, senior-level units with a standing responsibility to create NGPs, and their CEOs spent as much as 50% of their time working with these units. The payoff has been spectacular and lasting. For example, from 1985 to 2004, the medical devices company Medtronic grew revenues at 18% per year, earnings at 20%, and market capitalization at 30%. PMID:16649700

  1. FGF growth factor analogs

    DOEpatents

    Zamora, Paul O.; Pena, Louis A.; Lin, Xinhua; Takahashi, Kazuyuki

    2012-07-24

    The present invention provides a fibroblast growth factor heparin-binding analog of the formula: ##STR00001## where R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, X, Y and Z are as defined, pharmaceutical compositions, coating compositions and medical devices including the fibroblast growth factor heparin-binding analog of the foregoing formula, and methods and uses thereof.

  2. Simulating Underwater Leader Growth

    NASA Astrophysics Data System (ADS)

    Culver, Lee

    2005-11-01

    Dielectric breakdown in water is always preceded by the growth of leaders. The structure and growth of these leaders have been previously simulated with fractals; however, present mathematical models are rife with undesired parameters. We eliminate many of these parameters with a physical model that describes a leader as a protonic mobility wave. Graphical-simulation results will be presented and compared with photographic data.

  3. Short crack growth behavior

    SciTech Connect

    Sadananda, K.; Vasudevan, A.K.

    1997-12-01

    The authors have re-evaluated short crack growth behavior using concepts developed recently, and they show that these concepts provide a unified framework that can explain both short and long crack growth behavior without resorting to the crack closure effect. They consider that the behavior of long cracks, including the effects of load ratio, R, is fundamental. they had shown previously that, since fatigue is at least a two-parameter problem in that at least two load parameters are required for an unambiguous description, there are two critical driving forces required simultaneously for fatigue cracks to grow. In extending this analysis to the growth of short cracks, they reject the current notion of the lack of similitude for short cracks and express the similitude as a fundamental postulate that, for a given crack growth mechanism, equal crack tip driving forces result in equal crack growth rates. Short crack growth behavior confirms the concept that two parameters are required to define fatigue; consequently, for fatigue cracks to grow, two thresholds need to be satisfied simultaneously. The authors present examples from the literature to illustrate the concepts discussed.

  4. The biology of growth.

    PubMed

    Cameron, Noël

    2008-01-01

    Variability in human growth is not only in the timing of critical periods within the whole pattern of growth but also in the magnitude and rate of change coincident with the period. In addition, for a radical change in, e.g., height to occur there must also be changes in the anatomical parts that make up total height and these changes are themselves variable. Acceleration, for instance in height velocity, may be the result of different changes in the length of the spine, femur, and/or tibia, each of which may contribute differently to the total process. In addition, not only may the process be variable within a single child, it may also be variable between different children of the same or opposite sexes. The mathematical and statistical problems arising from the seemingly simple process of an increase in height are thus complex. In order to review the biology of human growth this contribution will discuss the principles of growth that are fundamental to our ability to interpret the response of the child to factors that might modify the genetically programmed pattern of growth from conception to maturity. In this way the biology of human growth will be described by a set of phenomena that reflect the actions of biological control mechanisms. These mechanisms are subject to genetic and environmental influences and their expression is characterised by variation in timing, magnitude, and duration. PMID:18196941

  5. A Decade of Growth

    NASA Technical Reports Server (NTRS)

    Johnson, Nicholas L.; Anzz-Meador, Phillip D.

    2001-01-01

    This paper examines the Space Surveillance Network catalog's growth in low Earth orbit (LEO) and the geosynchronous Earth orbit (GEO) over the decade 1990-2000. During this time, innovative space utilization concepts, e.g. the Iridium and Globalstar commercial communication satellite constellations, have increased the public's consciousness of space. At the same time, however, these constellations have increased spatial density per 10 km altitude bin by factors of two and three respectively. While not displaying as spectacular a growth in spatial density, other regions of space have grown steadily in terms of number, mass, size, and operational lifetime. In this work we categorize launch traffic by type (e.g. payload, rocket body, operational debris, fragmentation debris, or anomalous debris), mass, and size so as to present the observed growth numerically, in terms of mass, and in terms of cross-sectional area. GEO traffic is further categorized by operational longitude. Because growth itself defines only the instantaneous environment, we also examine the higher-order derivatives of growth. In addition, we compare the last decade's growth with modeling results to illustrate the subtle effects of inclination, eccentricity, and size, in addition to spatial densities, on estimating the collision probability. We identify those regions of space most subject to accidental collision.

  6. Entrepreneurship, Information, and Growth

    PubMed Central

    Bunten, Devin; Weiler, Stephan; Weiler, Stephan; Zahran, Sammy

    2016-01-01

    We examine the contribution to economic growth of entrepreneurial “marketplace information” within a regional endogenous growth framework. Entrepreneurs are posited to provide an input to economic growth through the information revealed by their successes and failures. We empirically identify this information source with the regional variation in establishment births and deaths, which create geographic information asymmetries that influence subsequent entrepreneurial activity and economic growth. We find that local establishment birth and death rates are significantly and positively correlated with subsequent entrepreneurship for US counties. To account for the potential endogeneity caused by forward-looking entrepreneurs, we utilize instruments based on historic mining activity. We find that the information spillover component of local establishment birth and death rates have significant positive effects on subsequent entrepreneurship and employment growth for US counties and metropolitan areas. With the help of these intruments, we show that establishment births have a positive and significant effect on future employment growth within all counties, and that in line with the information hypothesis, local establishment death rates have a similar positive effect within metropolitan counties. PMID:27516625

  7. Growth Hormone Deficiency in Children

    MedlinePlus

    ... many reasons for slow growth and below-average height in children. At times, slow growth is normal ... same age Signs of GHD • Slowed growth in height in infants, children, or adolescents (teenagers) • A young- ...

  8. Peptide growth factors, part B

    SciTech Connect

    Barnes, D.; Sirbasku, D.A.

    1987-01-01

    This book discusses the following topics: Platelet-Derived Growth Factor;Nerve and Glial Growth Factors;PC12 Pheochromocytoma Cells;Techniques for the Study of Growth Factor Activity;Genetic Approaches and Biological Effects.

  9. China's post-coal growth

    NASA Astrophysics Data System (ADS)

    Qi, Ye; Stern, Nicholas; Wu, Tong; Lu, Jiaqi; Green, Fergus

    2016-08-01

    Slowing GDP growth, a structural shift away from heavy industry, and more proactive policies on air pollution and clean energy have caused China's coal use to peak. It seems that economic growth has decoupled from growth in coal consumption.

  10. Protein crystal growth

    NASA Technical Reports Server (NTRS)

    Bugg, Charles E.

    1993-01-01

    Proteins account for 50% or more of the dry weight of most living systems and play a crucial role in virtually all biological processes. Since the specific functions of essentially all biological molecules are determined by their three-dimensional structures, it is obvious that a detailed understanding of the structural makeup of a protein is essential to any systematic research pertaining to it. At the present time, protein crystallography has no substitute, it is the only technique available for elucidating the atomic arrangements within complicated biological molecules. Most macromolecules are extremely difficult to crystallize, and many otherwise exciting and promising projects have terminated at the crystal growth stage. There is a pressing need to better understand protein crystal growth, and to develop new techniques that can be used to enhance the size and quality of protein crystals. There are several aspects of microgravity that might be exploited to enhance protein crystal growth. The major factor that might be expected to alter crystal growth processes in space is the elimination of density-driven convective flow. Another factor that can be readily controlled in the absence of gravity is the sedimentation of growing crystal in a gravitational field. Another potential advantage of microgravity for protein crystal growth is the option of doing containerless crystal growth. One can readily understand why the microgravity environment established by Earth-orbiting vehicles is perceived to offer unique opportunities for the protein crystallographer. The near term objectives of the Protein Crystal Growth in a Microgravity Environment (PCG/ME) project is to continue to improve the techniques, procedures, and hardware systems used to grow protein crystals in Earth orbit.

  11. Champions of profitable growth.

    PubMed

    Stewart, G Bennett

    2004-01-01

    Many companies have posted impressive top-line growth over the past two decades in their respective economic regions--for instance, Wal-Mart in North America, BP in Europe, Toyota in Asia, and News Corporation in the Southern Hemisphere. But which were the best at converting all of that revenue growth into shareholder value? Harvard Business Review asked C. Bennett Stewart III, the senior partner of the consulting firm Stern Stewart & Company, and his colleagues to come up with the answer. For the period 1983 to 2003, they assembled a list of the top 20 high-growth value adders (and laggards) in each of the four regions cited above. Their calculations gave equal weight to companies' revenue growth and market-value-added scores, revealing the important effect of region on the performance of companies in the same industry. For instance, while automakers are positioned high on the Asian list of high-growth value adders, U.S. carmakers GM and Ford--each of which reported revenue growth in excess of 100 billion dollars between 1983 and 2003--are among the value laggards on the North American list, as are DaimlerChrysler and Volkswagen on the European list. The Japanese win through better efficiency, higher quality, and narrower product mixes, the author says. And while there are four telecom companies represented among the European high-growth value adders, there are none on the North American list. That's probably because the European telecoms enjoyed more protective regulation, made fewer high-priced acquisitions, and didn't bet as big on the overblown dot-com economy, the author says. PMID:15241952

  12. Feeding rates affect growth, intestinal digestive and absorptive capabilities and endocrine functions of juvenile blunt snout bream Megalobrama amblycephala.

    PubMed

    Xu, Chao; Li, Xiang-Fei; Tian, Hong-Yan; Jiang, Guang-Zhen; Liu, Wen-Bin

    2016-04-01

    This study aimed to investigate the optimal feeding rate for juvenile blunt snout bream (average initial weight 23.74 ± 0.09 g) based on the results on growth performance, intestinal digestive and absorptive capabilities and endocrine functions. A total of 840 fish were randomly distributed into 24 cages and fed a commercial feed at six feeding rates ranging from 2.0 to 7.0 % body weight (BW)/day. The results indicated that weight gain rate increased significantly (P < 0.05) as feeding rates increased from 2.0 to 5.0 % BW/day, but decreased with the further increasing feeding rates (P > 0.05). Protein efficiency ratio and nitrogen and energy retention all showed a similar trend. However, feed conversion ratio increased significantly (P < 0.05) with increasing feeding rates. Feeding rates have little effects (P > 0.05) on whole-body moisture, ash and protein contents, but significantly (P < 0.05) affect both lipid and energy contents with the highest values both observed in fish fed 4.0 % BW/day. In addition, moderate ration sizes (2.0-4.0 % BW/day) resulted in the enhanced activities of intestinal enzymes, including lipase, protease, Na(+), K(+)-ATPase, alkaline phosphatase and creatine kinase. Furthermore, the mRNA levels of growth hormone, insulin-like growth factors-I, growth hormone receptor and neuropeptide all increased significantly (P < 0.05) as feeding rates increased from 2.0 to 5.0 % and 6.0 % BW/day, but decreased significantly (P < 0.05) with the further increase in feeding rates, whereas both leptin and cholecystokinin expressions showed an opposite trend. Based on the broken-line regression analysis of SGR against feeding rates, the optimal feeding rate for juvenile blunt snout bream was estimated to be 4.57 % BW/day. PMID:26597852

  13. Population growth and consumption.

    PubMed

    Chalkley, K

    1997-04-01

    The relationship between population growth, resource consumption, and environmental degradation is complex. The rise in "greenhouse gases" that will cause climatic change is clearly due to human activity, and pollutants are often concentrated in densely populated areas. However, even an area with a negative population growth, such as Russia, can experience severe environmental degradation due to poor management. Consumption patterns have the most effect on ozone depletion, while population growth threatens biodiversity of and within species through the destruction of ecosystems. Migration joins population growth and social factors, such as land inequality, as major causes of deforestation, and global demand for water is expected to increase faster than the rate of population growth. Coastal development and over-fishing threaten to deplete the oceans, while soil quality is threatened by inappropriate land use. Estimates of the earth's carrying capacity range from less than 3 billion to more than 44 billion people, indicating how difficult it is to assess this figure. Development efforts throughout the world may lead to human gains that will ultimately be negated by environmental losses. These factors have led to growing support for environmentally sustainable development. PMID:12319715

  14. Crystal Growth Control

    NASA Technical Reports Server (NTRS)

    Duval, Walter M. B.; Batur, Celal; Bennett, Robert J.

    1997-01-01

    We present an innovative design of a vertical transparent multizone furnace which can operate in the temperature range of 25 C to 750 C and deliver thermal gradients of 2 C/cm to 45 C/cm for the commercial applications to crystal growth. The operation of the eight zone furnace is based on a self-tuning temperature control system with a DC power supply for optimal thermal stability. We show that the desired thermal profile over the entire length of the furnace consists of a functional combination of the fundamental thermal profiles for each individual zone obtained by setting the set-point temperature for that zone. The self-tuning system accounts for the zone to zone thermal interactions. The control system operates such that the thermal profile is maintained under thermal load, thus boundary conditions on crystal growth ampoules can be predetermined prior to crystal growth. Temperature profiles for the growth of crystals via directional solidification, vapor transport techniques, and multiple gradient applications are shown to be easily implemented. The unique feature of its transparency and ease of programming thermal profiles make the furnace useful for scientific and commercial applications for the determination of process parameters to optimize crystal growth conditions.

  15. Bridgman crystal growth

    NASA Technical Reports Server (NTRS)

    Carlson, Frederick

    1990-01-01

    The objective of this theoretical research effort was to improve the understanding of the growth of Pb(x)Sn(1-x)Te and especially how crystal quality could be improved utilizing the microgravity environment of space. All theoretical growths are done using the vertical Bridgman method. It is believed that improved single crystal yields can be achieved by systematically identifying and studying system parameters both theoretically and experimentally. A computational model was developed to study and eventually optimize the growth process. The model is primarily concerned with the prediction of the thermal field, although mass transfer in the melt and the state of stress in the crystal were of considerable interest. The evolution is presented of the computer simulation and some of the important results obtained. Diffusion controlled growth was first studied since it represented a relatively simple, but nontheless realistic situation. In fact, results from this analysis prompted a study of the triple junction region where the melt, crystal, and ampoule wall meet. Since microgravity applications were sought because of the low level of fluid movement, the effect of gravitational field strength on the thermal and concentration field was also of interest. A study of the strength of coriolis acceleration on the growth process during space flight was deemed necessary since it would surely produce asymmetries in the flow field if strong enough. Finally, thermosolutal convection in a steady microgravity field for thermally stable conditions and both stable and unstable solutal conditions was simulated.

  16. Free dendritic growth

    NASA Technical Reports Server (NTRS)

    Glicksman, M. E.

    1984-01-01

    Free dendritic growth refers to the unconstrained development of crystals within a supercooled melt, which is the classical 'dendrite problem'. Great strides have been taken in recent years in both the theoretical understanding of dendritic growth and its experimental status. The development of this field will be sketched, showing that transport theory and interfacial thermodynamics (capillarity theory) were sufficient ingredients to develop a truly predictive model of dendrite formation. The convenient, but incorrect, notion of 'maximum velocity' was used for many years to estimate the behavior of dendritic transformations until supplanted by modern dynamic stability theory. The proper combinations of transport theory and morphological stability seem to able to predict the salient aspects of dendritic growth, especially in the neighborhood of the tip. The overall development of cast microstructures, such as equiaxed zone formation, rapidly solidified microstructures, etc., also seems to contain additional non-deterministic features which lie outside the current theories discussed here.

  17. Thick silicon growth techniques

    NASA Technical Reports Server (NTRS)

    Bates, H. E.; Mlavsky, A. I.; Jewett, D. N.

    1973-01-01

    Hall mobility measurements on a number of single crystal silicon ribbons grown from graphite dies have shown some ribbons to have mobilities consistent with their resistivities. The behavior of other ribbons appears to be explained by the introduction of impurities of the opposite sign. Growth of a small single crystal silicon ribbon has been achieved from a beryllia dia. Residual internal stresses of the order of 7 to 18,000 psi have been determined to exist in some silicon ribbon, particularly those grown at rates in excess of 1 in./min. Growth experiments have continued toward definition of a configuration and parameters to provide a reasonable yield of single crystal ribbons. High vacuum outgassing of graphite dies and evacuation and backfilling of growth chambers have provided significant improvements in surface quality of ribbons grown from graphite dies.

  18. Mechanics of Cell Growth

    PubMed Central

    Ateshian, Gerard A.; Morrison, Barclay; Holmes, Jeffrey W.; Hung, Clark T.

    2012-01-01

    Cell growth describes an essential feature of biological tissues. This growth process may be modeled by using a set of relatively simple governing equations based on the axioms of mass and momentum balance, and using a continuum framework that describes cells and tissues as mixtures of a solid matrix, a solvent and multiple solutes. In this model the mechanics of cell growth is driven by osmotic effects, regulated by the cells’ active uptake of solutes and passive uptake of solvent. By accounting for the anisotropy of the cells’ cytoskeletal structures or extracellular matrix, as well as external constraints, a wide variety of growing shapes may be produced as illustrated in various examples. PMID:22904576

  19. Naled ice growth

    NASA Astrophysics Data System (ADS)

    Schohl, G. A.; Ettema, R.

    1986-02-01

    Based on theoretical formulation and dimensional analysis, supported by the results of laboratory experiments, a theory and a detailed description of naled ice growth are presented. The theory, concepts, and data should be of interest to engineers concerned with the effects of naleds (also referred to as aufeis or icings) on engineering works. The growth of a two dimensional, or laterally confined (flume), naled is shown to depend primarily on seven, independent, dimensionless parameters. The early, two dimensional, phase of growth, a naled consists of a mixture of ice and water, or ice-water slush, forming on a frigid base. The influence of two of the three remaining parameters is not felt until after a transition time has passed. The continuing, cyclic process by which slush layers form and eventually freeze results in the ice laminations that are a feature of naled ice.

  20. New microbial growth factor

    NASA Technical Reports Server (NTRS)

    Bok, S. H.; Casida, L. E., Jr.

    1977-01-01

    A screening procedure was used to isolate from soil a Penicillium sp., two bacterial isolates, and a Streptomyces sp. that produced a previously unknown microbial growth factor. This factor was an absolute growth requirement for three soil bacteria. The Penicillium sp. and one of the bacteria requiring the factor, an Arthrobacter sp., were selected for more extensive study concerning the production and characteristics of the growth factor. It did not seem to be related to the siderochromes. It was not present in soil extract, rumen fluid, or any other medium component tested. It appears to be a glycoprotein of high molecular weight and has high specific activity. When added to the diets for a meadow-vole mammalian test system, it caused an increased consumption of diet without a concurrent increase in rate of weight gain.

  1. Elevated temperature crack growth

    NASA Technical Reports Server (NTRS)

    Kim, K. S.; Vanstone, R. H.; Malik, S. N.; Laflen, J. H.

    1988-01-01

    A study was performed to examine the applicability of path-independent (P-I) integrals to crack growth problems in hot section components of gas turbine aircraft engines. Alloy 718 was used and the experimental parameters included combined temperature and strain cycling, thermal gradients, elastic-plastic strain levels, and mean strains. A literature review was conducted of proposed P-I integrals, and those capable of analyzing hot section component problems were selected and programmed into the postprocessor of a finite element code. Detailed elastic-plastic finite element analyses were conducted to simulate crack growth and crack closure of the test specimen, and to evaluate the P-I integrals. It was shown that the selected P-I integrals are very effective for predicting crack growth for isothermal conditions.

  2. Liquid encapsulated crystal growth

    NASA Technical Reports Server (NTRS)

    Morrison, Andrew D. (Inventor)

    1989-01-01

    Low-defect crystals are grown in a closed ampoule under a layer of encapsulant. After crystal growth, the crystal is separated from the melt and moved into the layer of encapsulant and cooled to a first temperature at which crystal growth stops. The crystal is then moved into the inert gas ambient in the ampoule and further cooled. The crystal can be separated from the melt by decanting the melt into an adjacent reservoir or by rotating the ampoule to rotate the crystal into the encapsulant layer.

  3. Stochastic ontogenetic growth model

    NASA Astrophysics Data System (ADS)

    West, B. J.; West, D.

    2012-02-01

    An ontogenetic growth model (OGM) for a thermodynamically closed system is generalized to satisfy both the first and second law of thermodynamics. The hypothesized stochastic ontogenetic growth model (SOGM) is shown to entail the interspecies allometry relation by explicitly averaging the basal metabolic rate and the total body mass over the steady-state probability density for the total body mass (TBM). This is the first derivation of the interspecies metabolic allometric relation from a dynamical model and the asymptotic steady-state distribution of the TBM is fit to data and shown to be inverse power law.

  4. Liquid encapsulated crystal growth

    NASA Technical Reports Server (NTRS)

    Morrison, Andrew D. (Inventor)

    1987-01-01

    Low-defect crystals are grown in a closed ampoule under a layer of encapsulant. After crystal growth, the crystal is separated from the melt and moved into the layer of encapsulant and cooled to a first temperature at which crystal growth stops. The crystal is then moved into the inert gas ambient in the ampoule and further cooled. The crystal can be separated from the melt by decanting the melt into and adjacent reservoir or by rotating the ampoule to rotate the crystal into the encapsulant layer.

  5. Research District Seeing Growth

    SciTech Connect

    Madison, Alison L.

    2012-05-13

    Monthly economic diversity column for the Tri-City Herald (May 2012) - excerpt follows: It’s been a while since I’ve updated you on the Tri-Cities Research District, most certainly not for lack of new activity over the past several months. In fact, much has happened, and there’s more to come. I think many of us see new land development and construction as indicative of current or impending economic growth. So those of you who have ventured into North Richland either via Stevens Drive or George Washington Way lately have probably begun sensing and anticipating that such growth is afoot.

  6. Lattice models of biological growth

    SciTech Connect

    Young, D.A.; Corey, E.M. )

    1990-06-15

    We show that very simple iterative rules for the growth of cells on a two-dimensional lattice can simulate biological-growth phenomena realistically. We discuss random cellular automata models for the growth of fern gametophytes, branching fungi, and leaves, and for shape transformations useful in the study of biological variation and evolution. Although there are interesting analogies between biological and physical growth processes, we stress the uniqueness of biological automata behavior. The computer growth algorithms that successfully mimic observed growth behavior may be helpful in determining the underlying biochemical mechanisms of growth regulation.

  7. Demand, Growth, and Evolution

    ERIC Educational Resources Information Center

    Hoskins, Barbara

    2011-01-01

    The paradigm shift to engaged and collaborative learning delivered via distance education technologies has been led by practitioners in adult and continuing education. Online and blended courses are experiencing increased demand and continued growth at all levels of higher education, professional development, and K-12 education. Adult and…

  8. Essentials of Professional Growth.

    ERIC Educational Resources Information Center

    Wildman, Terry M.; Niles, Jerry A.

    1987-01-01

    The essentials needed for developing teaching novices into good teachers are autonomy, collaboration, and time. School improvement plans should include an understanding of the conditions that foster the professional growth of teachers. Provides a table and extensive list of references. (MD)

  9. Crystal growth and crystallography

    NASA Technical Reports Server (NTRS)

    Chernov, A. A.

    1998-01-01

    Selected topics that may be of interest for both crystal-structure and crystal-growth communities are overviewed. The growth of protein crystals, along with that of some other compounds, is one of the topics, and recent insights into related phenomena are considered as examples of applications of general principles. The relationship between crystal growth shape and structure is reviewed and an attempt to introduce semiquantitative characterization of binding for proteins is made. The concept of kinks for complex structures is briefly discussed. Even at sufficiently low supersaturations, the fluctuation of steps may not be sufficient to implement the Gibbs-Thomson law if the kink density is low enough. Subsurface ordering of liquids and growth of rough interfaces from melts is discussed. Crystals growing in microgravity from solution should be more perfect if they preferentially trap stress-inducing impurities, thus creating an impurity-depleted zone around themselves. Evidently, such a zone is developed only around the crystals growing in the absence of convection. Under terrestrial conditions, the self-purified depleted zone is destroyed by convection, the crystal traps more impurity and grows stressed. The stress relief causes mosaicity. In systems containing stress-inducing but poorly trapped impurities, the crystals grown in the absence of convection should be worse than those of their terrestrial counterparts.

  10. Growth through Levels

    ERIC Educational Resources Information Center

    Thissen, David

    2015-01-01

    In "Using Learning Progressions to Design Vertical Scales that Support Coherent Inferences about Student Growth" (hereafter ULR), Briggs and Peck suggest that learning progressions could be used as the basis of vertical scales with naturally benchmarked descriptions of student proficiency. They propose and provide a single example of a…

  11. Growth Plate Injuries

    MedlinePlus

    ... or crushed, the growth plate may close prematurely, forming a bony bridge or “bar.” The risk of ... this publication: James S. Panagis, M.D., M.P.H., NIAMS/NIH; R. Tracy Ballock, M.D., Case ...

  12. Betting on Growth.

    ERIC Educational Resources Information Center

    Spoor, Dana L.

    1997-01-01

    Discusses how the Clark County School District (Las Vegas) is able to successfully manage approximately 8% student enrollment growth per year along with one new building opening on an average of every 15 days. Examines managing new facility construction, making provisions for new technology, and using portable buildings to accommodate student…

  13. Dew nucleation and growth

    NASA Astrophysics Data System (ADS)

    Beysens, Daniel

    2006-11-01

    Dew is the condensation of water vapor into liquid droplets on a substrate. It is characterized by an initial heterogeneous nucleation on a substrate and a further growth of droplets. The presence of a substrate that geometrically constrains the growth is the origin of the peculiarities and richness of the phenomenon. A key point is the drop interaction through drop fusion or coalescence, which leads to scaling in the growth and gives universality to the process. As a matter of fact, growth dynamics are only dependent on substrate and drop dimensionality. Coalescence events lead to temporal and spatio-temporal fluctuations in the substrate coverage, drop configuration, etc., which give rise to a very peculiar dynamics. When the substrate is a liquid or a liquid crystal, the drop pattern can exhibit special spatial order, such as crystalline, hexatic phases and fractal contours. Condensation on a solid substrate near its melting point can make the drop jump. The applications of monitoring dew formation are manifold. Examples can be found in medicine (sterilization process), agriculture (green houses) and hydrology (production of drinkable water). To cite this article: D. Beysens, C. R. Physique 7 (2006).

  14. Bridgman Growth of Germanium

    NASA Technical Reports Server (NTRS)

    Szofran, F. R.; Volz, M. P.; Cobb, S. D.; Motakef, S.

    1997-01-01

    The high-magnetic-field crystal growth facility at the Marshall Space Flight Center will be briefly described. This facility has been used to grow bulk germanium by the Bridgman technique in magnetic fields up to 5 Tesla. The results of investigations of ampoule material on the interface shape and thermal field applied to the melt on stability against convection will be discussed.

  15. The Bacterial Growth Curve.

    ERIC Educational Resources Information Center

    Paulton, Richard J. L.

    1991-01-01

    A procedure that allows students to view an entire bacterial growth curve during a two- to three-hour student laboratory period is described. Observations of the lag phase, logarithmic phase, maximum stationary phase, and phase of decline are possible. A nonpathogenic, marine bacterium is used in the investigation. (KR)

  16. Plant growth promoting rhizobacterium

    SciTech Connect

    Doktycz, Mitchel John; Pelletier, Dale A.; Schadt, Christopher Warren; Tuskan, Gerald A.; Weston, David

    2015-08-11

    The present invention is directed to the Pseudomonas fluorescens strain GM30 deposited under ATCC Accession No. PTA-13340, compositions containing the GM30 strain, and methods of using the GM30 strain to enhance plant growth and/or enhance plant resistance to pathogens.

  17. Scaling and Urban Growth

    NASA Astrophysics Data System (ADS)

    Benguigui, L.; Czamanski, D.; Marinov, M.

    This paper presents an analysis of the growth of towns in the Tel Aviv metropolis. It indicates a similarity in the variation of populations so that the population functions can be scaled and superposed one onto the other. This is a strong indication that the growth mechanism for all these towns is the same. Two different models are presented to interpret the population growth: one is an analytic model while the other is a computer simulation. In the dynamic analytic model, we introduced the concept of characteristic time. The growth has two parts: in the first, the derivative is an increasing function, the town is very attractive and there is short delay between decision to build and complete realization of the process. At this time, there is no shortage of land. However, around a specific time, the delay begins to increase and there is lack of available land. The rate of the population variation decreases until saturation. The two models give a good quantitative description.

  18. Teaching about Population Growth.

    ERIC Educational Resources Information Center

    Otero, George G., Jr., Comp.

    This teaching guide contains 20 activities on population growth for students in grades 6-12. The purpose is to help students gain the skills, knowledge, and understanding of population dynamics so that they can make rational decisions and take responsible action regarding population matters and public policy. Activities are organized around the…

  19. Protein crystal growth tray assembly

    NASA Technical Reports Server (NTRS)

    Carter, Daniel C. (Inventor); Miller, Teresa Y. (Inventor)

    1992-01-01

    A protein crystal growth tray assembly includes a tray that has a plurality of individual crystal growth chambers. Each chamber has a movable pedestal which carries a protein crystal growth compartment at an upper end. The several pedestals for each tray assembly are ganged together for concurrent movement so that the solutions in the various pedestal growth compartments can be separated from the solutions in the tray's growth chambers until the experiment is to be activated.

  20. Growth factors in haemopoiesis.

    PubMed

    Jones, A L; Millar, J L

    1989-01-01

    Haemopoietic growth factors have for over two decades allowed experimentalists to grow haemopoietic bone marrow cells in vitro. With refinements in technique and the discovery of novel growth factors, all of the known haemopoietic lineages can now be grown in vitro. This has allowed a much greater understanding of the complex process of haemopoiesis from the haemopoietic stem cell to the mature, functioning end-cell. The in vivo action of these growth factors has been harder to investigate. Although recombinant technology has afforded us the much greater quantities necessary for in vivo work, problems remain with administration because of effects on other tissues. Interpretation of results is difficult because of the complex inter-relationships which exist between factors. Some of these have been defined in vitro and it appears likely that they also operate in vivo. Erythropoietin is a physiological regulator of erythropoiesis. It has been detected in vivo with levels responding appropriately to stress (i.e. elevated in anaemia) and, when administered in pharmacological doses, has been shown to correct anaemia. Granulocyte/macrophage colony-stimulating factor (GM-CSF) has been detected in vivo and may influence the production and function of granulocytes and macrophages, although how it is regulated is unknown. Granulocyte colony-stimulating factor (G-CSF) and macrophage colony-stimulating factor are ore lineage-specific. Interleukin 3 (IL-3), although it has not been detected in vivo, may act on a primitive marrow precursor by expanding the population and making these cells more susceptible to other growth factors, such as GM-CSF. Interleukin 1 (IL-1) has been detected in vivo, does not appear to have any isolated action on bone marrow (except possibly radioprotection) but probably acts synergistically with other growth factors, such as G-CSF. Interleukins 2, 4, 5 and 6 have not been detected in vivo. All have effects on B-cells. In addition IL-2 is an essential

  1. Coupled Growth in Hypermonotectics

    NASA Technical Reports Server (NTRS)

    Andrews, J. Barry; Coriell, Sam R.

    2001-01-01

    The overall objective of this project is to obtain a fundamental understanding of the physics controlling solidification processes in immiscible alloy systems. The investigation involves both experimentation and the development of a model describing solidification in monotectic systems. The experimental segment was designed to first demonstrate that it is possible to obtain interface stability and steady state coupled growth in hypermonotectic alloys through microgravity processing. Microgravity results obtained to date have verified this possibility. Future flights will permit experimental determination of the limits of interface stability and the influence of alloy composition and growth rate on microstructure. The objectives of the modeling segment of the investigation include prediction of the limits of interface stability, modeling of convective flow due to residual acceleration, and the influence of surface tension driven flows at the solidification interface. The study of solidification processes in immiscible alloy systems is hindered by the inherent convective flow that occurs on Earth and by the possibility of sedimentation of the higher density immiscible liquid phase. It has been shown that processing using a high thermal gradient and a low growth rate can lead to a stable macroscopically planar growth front even in hypermonotectic alloys. Processing under these growth conditions can avoid constitutional supercooling and prevent the formation of the minor immiscible liquid phase in advance of the solidification front. However, the solute depleted boundary layer that forms in advance of the solidification front is almost always less dense than the liquid away from the solidification front. As a result, convective instability is expected. Ground based testing has indicated that convection is a major problem in these alloy systems and leads to gross compositional variations along the sample and difficulties maintaining interface stability. Sustained low

  2. Mechanobiology of interfacial growth

    NASA Astrophysics Data System (ADS)

    Ciarletta, P.; Preziosi, L.; Maugin, G. A.

    2013-03-01

    A multiscale analysis integrating biomechanics and mechanobiology is today required for deciphering the crosstalk between biochemistry, geometry and elasticity in living materials. In this paper we derive a unified thermomechanical theory coupling growth processes with mass transport phenomena across boundaries and/or material interfaces. Inside a living system made by two contiguous bodies with varying volumes, an interfacial growth mechanism is considered to force fast but continuous variations of the physical fields inside a narrow volume across the material interface. Such a phenomenon is modelled deriving homogenized surface fields on a growing non-material discontinuity, possibly including a singular edge line. A number of balance laws is derived for imposing the conservation of the thermomechanical properties of the biological system. From thermodynamical arguments we find that the normal displacement of the non-material interface is governed by the jump of a new form of material mechanical-energy flux, also involving the kinetic energies and the mass fluxes. Furthermore, the configurational balance indicates that the surface Eshelby tensor is the tangential stress measure driving the material inhomogeneities on the non-material interface. Accordingly, stress-dependent evolution laws for bulk and interfacial growth processes are derived for both volume and surface fields. The proposed thermomechanical theory is finally applied to three biological system models. The first two examples are focused on stress-free growth problems, concerning the morphogenesis of animal horns and of seashells. The third application finally deals with the stress-driven surface evolution of avascular tumours with heterogeneous structures. The results demonstrate that the proposed theory can successfully model those biological systems where growth and mass transport phenomena interact at different length-scales. Coupling biological, mechanical and geometrical factors, the proposed

  3. Initial steps of aerosol growth

    NASA Astrophysics Data System (ADS)

    Kulmala, M.; Laakso, L.; Lehtinen, K. E. J.; Riipinen, I.; Dal Maso, M.; Anttila, T.; Kerminen, V.-M.; Hõrrak, U.; Vana, M.; Tammet, H.

    2004-12-01

    The formation and growth of atmospheric aerosols depend on several steps, namely nucleation, initial steps of growth and subsequent - mainly condensational - growth. This work focuses on the initial steps of growth, meaning the growth right after nucleation, where the interplay of curvature effects and thermodynamics has a significant role on the growth kinetics. More specifically, we investigate how ion clusters and aerosol particles grow from 1.5 nm to 20 nm (diameter) in atmospheric conditions using experimental data obtained by air ion and aerosol spectrometers. The measurements have been performed at a boreal forest site in Finland. The observed trend that the growth rate seems to increase as a function of size can be used to investigate possible growth mechanisms. Such a growth rate is consistent with a recently suggested nano-Köhler mechanism, in which growth is activated at a certain size with respect to condensation of organic vapors. The results also imply that charge-enhanced growth associated with ion-mediated nucleation plays only a minor role in the initial steps of growth, since it would imply a clear decrease of the growth rate with size. Finally, further evidence was obtained on the earlier suggestion that atmospheric nucleation and the subsequent growth of fresh nuclei are likely to be uncoupled phenomena via different participating vapors.

  4. Initial steps of aerosol growth

    NASA Astrophysics Data System (ADS)

    Kulmala, O.; Laakso, L.; Lehtinen, K. E. J.; Riipinen, I.; Dal Maso, M.; Anttila, T.; Kerminen, V.-M.; Hõrrak, U.; Vana, M.; Tammet, H.

    2004-09-01

    The formation and growth of atmospheric aerosols depend on several steps, namely nucleation, initial steps of growth and subsequent - mainly condensational - growth. This work focuses on the initial steps of growth, meaning the growth right after nucleation, where the interplay of curvature effects and thermodynamics has a significant role on the growth kinetics. More specifically, we investigate how ion clusters and aerosol particles grow from 1.5 nm to 20 nm in atmospheric conditions using experimental data obtained by air ion and aerosol spectrometers. The measurements have been performed at a boreal forest site in Finland. The observed trend that the growth rate seems to increase as a function of size can be used to investigate possible growth mechanisms. Such a growth rate is consistent with a recently suggested nano-Köhler mechanism, in which growth is activated at a certain size with respect to condensation of organic vapors. The results also imply that charge-enhance growth associated with ion-mediated nucleation plays only a minor role in the initial steps of growth, since it would imply a clear decrease of the growth rate with size. Finally, further evidence was obtained on the earlier suggestion that atmospheric nucleation and the subsequent growth of fresh nuclei are likely to be uncoupled phenomena via different participating vapors.

  5. Epidermal growth factor and growth in vivo

    SciTech Connect

    Rhodes, J.A.

    1986-01-01

    Epidermal growth factor (EGF) causes a dose-dependent thickening of the epidermis in suckling mice. The cellular mechanisms underlying this thickening were analyzed by measuring the effect of EGF on the cell-cycle. Neonatal mice were given daily injections of either 2ug EGF/g body weight/day or an equivalent volume of saline, and on the seventh day received a single injection of /sup 3/H-thymidine. At various times the mice were perfused with fixative; 1um sections of skin were stained with a modification of Harris' hematoxylin and were autoradiographed. The sections were analyzed using three methods based on the dependence on time after injection of /sup 3/H-thymidine of: frequency of labelled mitoses, labelling index, and reciprocal grains/nucleus. It was found that EGF caused a two-fold increase in the cell production rate. The effect of exogenous EGF on the morphology of gastric mucosa and incisors of suckling mice was also studied. The gastric mucosa appeared thicker in EGF-treated animals, but the effect was not statistically significant. In contrast to its effect on epidermis and gastric mucosa, EGF caused a significant, dose-dependent decrease in the size of the incisors. Because the mouse submandibular salivary gland is the major source of EGF the effect of sialoadenectomy on female reproductive functions was examined. Ablation of the submandibular gland had no effect on: length of estrus cycle, ability of the female to produce litters, length of the gestation period, litter size, and weight of the litter at birth. There was also no effect on survival of the offspring or on age at which the eyelids separated.

  6. Dendritic Growth Investigators

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Representatives of NASA materials science experiments supported the NASA exhibit at the Rernselaer Polytechnic Institute's Space Week activities, April 5 through 11, 1999. From left to right are: Angie Jackman, project manager at NASA's Marshall Space Flight Center for dendritic growth experiments; Dr. Martin Glicksman of Rennselaer Polytechnic Instutute, Troy, NY, principal investigator on the Isothermal Dendritic Growth Experiment (IDGE) that flew three times on the Space Shuttle; and Dr. Matthew Koss of College of the Holy Cross in Worcester, MA, a co-investigator on the IDGE and now principal investigator on the Transient Dendritic Solidification Experiment being developed for the International Space Station (ISS). The image at far left is a dendrite grown in Glicksman's IDGE tests aboard the Shuttle. Glicksman is also principal investigator for the Evolution of Local Microstructures: Spatial Instabilities of Coarsening Clusters.

  7. Chemical vapor deposition growth

    NASA Technical Reports Server (NTRS)

    Ruth, R. P.; Manasevit, H. M.; Kenty, J. L.; Moudy, L. A.; Simpson, W. I.; Yang, J. J.

    1976-01-01

    A chemical vapor deposition (CVD) reactor system with a vertical deposition chamber was used for the growth of Si films on glass, glass-ceramic, and polycrystalline ceramic substrates. Silicon vapor was produced by pyrolysis of SiH4 in a H2 or He carrier gas. Preliminary deposition experiments with two of the available glasses were not encouraging. Moderately encouraging results, however, were obtained with fired polycrystalline alumina substrates, which were used for Si deposition at temperatures above 1,000 C. The surfaces of both the substrates and the films were characterized by X-ray diffraction, reflection electron diffraction, scanning electron microscopy optical microscopy, and surface profilometric techniques. Several experiments were conducted to establish baseline performance data for the reactor system, including temperature distributions on the sample pedestal, effects of carrier gas flow rate on temperature and film thickness, and Si film growth rate as a function of temperature.

  8. Zircon growth in slate

    NASA Astrophysics Data System (ADS)

    Dempster, T. J.; Hay, D. C.; Bluck, B. J.

    2004-03-01

    Clastic sedimentary and low-grade metasedimentary rocks preserve populations of detrital zircons because of the unreactive nature of this mineral. However, evidence of new zircon growth has been found within highly heterogeneous populations of zircon from several greenschist facies slates from the Scottish Highlands. Small (<10 μm), anhedral, unzoned zircons and discrete overgrowths on rounded detrital grains are very common. These new fine-grained zircons have crystallized at temperatures below 350 °C and have been observed only in polished thin sections; they are absent from conventional mineral separates. Typical separation techniques create severe biases in the heavy-mineral populations of metasedimentary rocks, and recognition of the growth of zircon in such conditions may allow isotopic dating of low-temperature events.

  9. Thyroid Growth and Cancer.

    PubMed

    Williams, Dillwyn

    2015-09-01

    It is proposed that most papillary thyroid cancers originate in infancy and childhood, based on the early rise in sporadic thyroid carcinoma incidence, the pattern of radiation-induced risk (highest in those exposed as infants), and the high prevalence of sporadic papillary thyroid cancers in children and adolescents (ultrasound screening after the Fukushima accident). The early origin can be linked to the growth pattern of follicular cells, with a high mitotic rate in infancy falling to very low replacement levels in adult life. The cell of origin of thyroid cancers, the differentiated follicular cell, has a limited growth potential. Unlike cancers originating in stem cells, loss of the usually tight link between differentiation and replicative senescence is required for immortalisation. It is suggested that this loss distinguishes larger clinically significant papillary thyroid cancers from micro-papillary thyroid cancers of little clinical significance. Papillary carcinogenesis can then be divided into 3 stages: (1) initiation, the first mutation in the carcinogenic cascade, for radiation-induced papillary thyroid cancers usually a RET rearrangement, (2) progression, acquisition of the additional mutations needed for low-grade malignancy, and (3) escape, further mutations giving immortality and a higher net growth rate. Most papillary thyroid cancers will not have achieved full immortality by adulthood, and remain as so-called micro-carcinomas with a very low growth rate. The use of the term 'cancer' to describe micro-papillary thyroid cancers in older patients encourages overtreatment and alarms patients. Invasive papillary thyroid tumours show a spectrum of malignancy, which at its lowest poses no threat to life. The treatment protocols and nomenclature for small papillary carcinomas need to be reconsidered in the light of the new evidence available, the continuing discovery of smaller lesions, and the model of thyroid carcinogenesis proposed. PMID:26558233

  10. Correlations and droplet growth

    NASA Technical Reports Server (NTRS)

    Marder, M.

    1985-01-01

    Consideration is given to the time development of a system in which small spheres of a stable phase grow out of a supersaturated melt. The spheres then grow and shrink in a manner similar to Ostwald ripening. The growth process of pairs of particles in an effective background accounts for can be used to explain the long time correlations which develop in the system. The correlations broaden the distribution of particles sizes, even for relatively dilute systems.

  11. [Poverty and population growth].

    PubMed

    1983-07-01

    In the mid-1970s, some 120 million Latin Americans were unable to satisfy their most basic material needs. 55 million of them were in extreme indigency, unable to satisfy their minimal food needs even by using their entire incomes for that purpose. The rapid rate of demographic growth in Latin America influences the growth of the poor strata, who in absolute and relative terms show the highest rates of population growth. Despite heterogeneity in the manifestations of poverty, the poor have certain traits in common: employment outside the modern sector, with low productivity and little hope of generating stable incomes, low consumption capability, and lack of political power. 1 of the great problems of economic development in Latin America is the exclusion of the poorest strata from employment in better paid jobs. The high rate of fertility and rapid population growth provoke a negative interaction between population and development, in which the poorest strata reproduce most rapidly, becoming even poorer. A program of family planning within a development effort providing employment and income is needed to mitigate the problem, and no avenue or effort of implementation should be neglected on ideological grounds. Between 1960-70, the share of the poorest 20% of the population declined from 3.1% to 2.5% of the toal income of the region, while that of the poorest 1/2 increased slightly from 13.4% to 13.9%. In 1970 the poorest 20% had a per capita income of about US $70/year. It has been estimated that the proportion of the poor in Latin America declined from 51% in 1960 to 40% in 1970 and 33% at present, but the absolute number of persons affected continues to increase. PMID:12339314

  12. Thyroid Growth and Cancer

    PubMed Central

    Williams, Dillwyn

    2015-01-01

    It is proposed that most papillary thyroid cancers originate in infancy and childhood, based on the early rise in sporadic thyroid carcinoma incidence, the pattern of radiation-induced risk (highest in those exposed as infants), and the high prevalence of sporadic papillary thyroid cancers in children and adolescents (ultrasound screening after the Fukushima accident). The early origin can be linked to the growth pattern of follicular cells, with a high mitotic rate in infancy falling to very low replacement levels in adult life. The cell of origin of thyroid cancers, the differentiated follicular cell, has a limited growth potential. Unlike cancers originating in stem cells, loss of the usually tight link between differentiation and replicative senescence is required for immortalisation. It is suggested that this loss distinguishes larger clinically significant papillary thyroid cancers from micro-papillary thyroid cancers of little clinical significance. Papillary carcinogenesis can then be divided into 3 stages: (1) initiation, the first mutation in the carcinogenic cascade, for radiation-induced papillary thyroid cancers usually a RET rearrangement, (2) progression, acquisition of the additional mutations needed for low-grade malignancy, and (3) escape, further mutations giving immortality and a higher net growth rate. Most papillary thyroid cancers will not have achieved full immortality by adulthood, and remain as so-called micro-carcinomas with a very low growth rate. The use of the term ‘cancer’ to describe micro-papillary thyroid cancers in older patients encourages overtreatment and alarms patients. Invasive papillary thyroid tumours show a spectrum of malignancy, which at its lowest poses no threat to life. The treatment protocols and nomenclature for small papillary carcinomas need to be reconsidered in the light of the new evidence available, the continuing discovery of smaller lesions, and the model of thyroid carcinogenesis proposed. PMID

  13. [Hormones and hair growth].

    PubMed

    Trüeb, R M

    2010-06-01

    With respect to the relationship between hormones and hair growth, the role of androgens for androgenetic alopecia (AGA) and hirsutism is best acknowledged. Accordingly, therapeutic strategies that intervene in androgen metabolism have been successfully developed for treatment of these conditions. Clinical observations of hair conditions involving hormones beyond the androgen horizon have determined their role in regulation of hair growth: estrogens, prolactin, thyroid hormone, cortisone, growth hormone (GH), and melatonin. Primary GH resistance is characterized by thin hair, while acromegaly may cause hypertrichosis. Hyperprolactinemia may cause hair loss and hirsutism. Partial synchronization of the hair cycle in anagen during late pregnancy points to an estrogen effect, while aromatase inhibitors cause hair loss. Hair loss in a causal relationship to thyroid disorders is well documented. In contrast to AGA, senescent alopecia affects the hair in a diffuse manner. The question arises, whether the hypothesis that a causal relationship exists between the age-related reduction of circulating hormones and organ function also applies to hair and the aging of hair. PMID:20502852

  14. Some Aviation Growth Events

    NASA Technical Reports Server (NTRS)

    Spearman, M. Leroy

    2002-01-01

    The growth of aviation since the first flight of a heavier-than-air powered manned vehicle in 1903 has been somewhat remarkable. Some of the events that have influenced this growth are reviewed in this paper. This review will include some events prior to World War I; the influence of the war itself; the events during the post-war years including the establishment of aeronautical research laboratories; and the influence of World War II which, among other things, introduced new technologies that included rocket and jet propulsion and supersonic aerodynamics. The subsequent era of aeronautical research and the attendant growth in aviation over the past half century will be reviewed from the view point of the author who, since 1944, has been involved in the NACA/NASA aeronautical research effort at what is now the Langley Research Center in Hampton, Virginia. The review will discuss some of the research programs related to the development of some experimental aircraft, the Century series of fighter aircraft, multi-mission aircraft, advanced military aircraft and missiles, advanced civil aircraft, supersonic transports, spacecraft and others.

  15. Can Growth Be Green?

    PubMed

    Gough, Ian

    2015-01-01

    This short article, based on a presentation at the London School of Economics, criticizes the common opinion that "green growth" offers a relatively painless - some even say pain-free - transition path for capitalist economies. After a brief summary of the daunting arithmetic entailed in combining fast decarbonization with continuing growth, the article advances 3 propositions. First, market-based carbon mitigation programs, such as carbon trading, cannot be sufficient and must be coupled with other policy pillars that foster transformative investment and widespread regulation. Second, a political economy of climate policy needs to draw on the lessons of comparative social policy research, which emphasizes the role of international pressures, interests, institutions, and ideas. Taking these into account gives a more realistic perspective on climate policy making in today's neoliberal world. Third, more radical policies on both consumption and production are called for, to ensure that carbon mitigation is not pursued at the expense of equity and social welfare. These include policies to restrain high-carbon luxury consumption and a transition toward shorter paid working time. The conclusion is that a realistic program of green growth will be immensely difficult and entail radical political change. PMID:26077854

  16. Facilitating post traumatic growth

    PubMed Central

    Turner, de Sales; Cox, Helen

    2004-01-01

    Background Whilst negative responses to traumatic injury have been well documented in the literature, there is a small but growing body of work that identifies posttraumatic growth as a salient feature of this experience. We contribute to this discourse by reporting on the experiences of 13 individuals who were traumatically injured, had undergone extensive rehabilitation and were discharged from formal care. All participants were injured through involvement in a motor vehicle accident, with the exception of one, who was injured through falling off the roof of a house. Methods In this qualitative study, we used an audio-taped in-depth interview with each participant as the means of data collection. Interviews were transcribed verbatim and analysed thematically to determine the participants' unique perspectives on the experience of recovery from traumatic injury. In reporting the findings, all participants' were given a pseudonym to assure their anonymity. Results Most participants indicated that their involvement in a traumatic occurrence was a springboard for growth that enabled them to develop new perspectives on life and living. Conclusion There are a number of contributions that health providers may make to the recovery of individuals who have been traumatically injured to assist them to develop new views of vulnerability and strength, make changes in relationships, and facilitate philosophical, physical and spiritual growth. PMID:15248894

  17. Gambling on growth.

    PubMed

    Feeney, A

    1990-01-01

    When the assumption is made that economic growth must be increased by 10% to accommodate population increases and to reduce poverty, the question is raised as to whether or not sustainable development is possible. The human population increased 3 times since 1900, and global economic activity has increased 7 times faster than population. Use of fossil fuels has increased by 30 times, and industrial production has increased by 50 times. The by-products of population growth and economic activity are loss of tropical rainforests; species extinction; desertification in Africa, India, and the US; toxic and radioactive pollution; and greenhouse warming and ozone depletion. The atmosphere's stability and human habitation is threatened. Sustainable development, as defined by the World Commission on Environment and Development (WCED) in "Our Common Future," is meeting present needs but not at the expense of future needs. Economic growth must proceed at different rates in different countries to close the gap between the rich and poor. Economic expansion has been criticized by the president of Negative Population Growth and the Environmental Defense Fund's coordinator of reform for the World Bank's environmental policies and Third World countries. US government response during the Reagan administration has been indifference, while support has come from the World Resources Institute, the Worldwatch Institute, the US National Wildlife Federation, and the Population Reference Bureau. Recent support has come from signers of the "G-7 Summit" and from IBM and the Dow Chemical Company. A few shared tenets are 1) that economic development is not sustainable, 2) environmental reforms are necessary to make development sustainable, 3) a trade-off is needed to increase Third World energy use, and 4) population must be stabilized. Many proposals have been offered including reducing population to 2 billion, or 40% of the current level. Reducing poverty globally is an environmentally sound

  18. Growth hormone stimulation test (image)

    MedlinePlus

    ... test is performed by administering the amino acid arginine in a vein to raise hGH levels. The ... to secrete growth hormone in response to the arginine. Lack of hGH can cause growth retardation in ...

  19. The Real Limits to Growth

    ERIC Educational Resources Information Center

    Ross, W. A.

    1975-01-01

    Fundamental conservation principles indicate existence of a limit to growth operative in the near future. General properties of geometric growth are presented with timescales showing population increases. Projections for natural and energy resource consumption are examined. (BP)

  20. What Are Growth Plate Injuries?

    MedlinePlus

    ... activities. Other reasons for growth plate injuries are:  Child abuse  Injury from extreme cold (for example, frostbite)  Radiation ( ... problems) treats most growth plate injuries. At other times, the child will see a pediatric orthopaedic surgeon (a doctor ...

  1. What Are Growth Plate Injuries?

    MedlinePlus

    ... activities. Other reasons for growth plate injuries are: Child abuse Injury from extreme cold (for example, frostbite) Radiation ( ... problems) treats most growth plate injuries. At other times, the child will see a pediatric orthopaedic surgeon (a doctor ...

  2. Circulating levels of insulin-like growth factor-I (IGF-I) correlate with disease status in leprosy

    PubMed Central

    2011-01-01

    Background Caused by Mycobacterium leprae (ML), leprosy presents a strong immune-inflammatory component, whose status dictates both the clinical form of the disease and the occurrence of reactional episodes. Evidence has shown that, during the immune-inflammatory response to infection, the growth hormone/insulin-like growth factor-I (GH/IGF-I) plays a prominent regulatory role. However, in leprosy, little, if anything, is known about the interaction between the immune and neuroendocrine systems. Methods In the present retrospective study, we measured the serum levels of IGF-I and IGBP-3, its major binding protein. These measurements were taken at diagnosis in nonreactional borderline tuberculoid (NR BT), borderline lepromatous (NR BL), and lepromatous (NR LL) leprosy patients in addition to healthy controls (HC). LL and BL patients who developed reaction during the course of the disease were also included in the study. The serum levels of IGF-I, IGFBP-3 and tumor necrosis factor-alpha (TNF-α) were evaluated at diagnosis and during development of reversal (RR) or erythema nodosum leprosum (ENL) reaction by the solid phase, enzyme-labeled, chemiluminescent-immunometric method. Results The circulating IGF-I/IGFBP-3 levels showed significant differences according to disease status and occurrence of reactional episodes. At the time of leprosy diagnosis, significantly lower levels of circulating IGF-I/IGFBP-3 were found in NR BL and NR LL patients in contrast to NR BT patients and HCs. However, after treatment, serum IGF-I levels in BL/LL patients returned to normal. Notably, the levels of circulating IGF-I at diagnosis were low in 75% of patients who did not undergo ENL during treatment (NR LL patients) in opposition to the normal levels observed in those who suffered ENL during treatment (R LL patients). Nonetheless, during ENL episodes, the levels observed in RLL sera tended to decrease, attaining similar levels to those found in NR LL patients. Interestingly, IGF

  3. Advanced dendritic web growth development

    NASA Technical Reports Server (NTRS)

    Hopkins, R. H.

    1985-01-01

    A program to develop the technology of the silicon dendritic web ribbon growth process is examined. The effort is being concentrated on the area rate and quality requirements necessary to meet the JPL/DOE goals for terrestrial PV applications. Closed loop web growth system development and stress reduction for high area rate growth is considered.

  4. Approaches to Academic Growth Assessment

    ERIC Educational Resources Information Center

    Anderman, Eric M.; Gimbert, Belinda; O'Connell, Ann A.; Riegel, Lisa

    2015-01-01

    Background: There is much interest in assessing growth in student learning. Assessments of growth have important implications and affect many policy decisions at many levels. Aims: In the present article, we review some of the different approaches to measuring growth and examine the implications of their usage. Sample: Samples used in research on…

  5. Hormonal Control of Fetal Growth.

    ERIC Educational Resources Information Center

    Cooke, Paul S.; Nicoll, Charles S.

    1983-01-01

    Summarizes recent research on hormonal control of fetal growth, presenting data obtained using a new method for studying the area. Effects of endocrine ablations and congenital deficiencies, studies of hormone/receptor levels, in-vitro techniques, hormones implicated in promoting fetal growth, problems with existing methodologies, and growth of…

  6. Isothermal Dendritic Growth Experiment Video

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This video, captured during the Isothermal Dendritic Growth Experiment (IDGE) flown on STS-87 as a part of the fourth United States Microgravity payload, shows the growth of a dendrite, and the surface solidification that occurred on the front and back windows of the growth chamber. Dendrites are tiny, tree like structures that form as metals solidify.

  7. Protein crystal growth - Growth kinetics for tetragonal lysozyme crystals

    NASA Technical Reports Server (NTRS)

    Pusey, M. L.; Snyder, R. S.; Naumann, R.

    1986-01-01

    Results are reported from theoretical and experimental studies of the growth rate of lysozyme as a function of diffusion in earth-gravity conditions. The investigations were carried out to form a comparison database for future studies of protein crystal growth in the microgravity environment of space. A diffusion-convection model is presented for predicting crystal growth rates in the presence of solutal concentration gradients. Techniques used to grow and monitor the growth of hen egg white lysozyme are detailed. The model calculations and experiment data are employed to discuss the effects of transport and interfacial kinetics in the growth of the crystals, which gradually diminished the free energy in the growth solution. Density gradient-driven convection, caused by presence of the gravity field, was a limiting factor in the growth rate.

  8. Global population growth.

    PubMed

    Langmore, J

    1992-07-01

    The global population passed 5 billion in 1987. In the year 2000 the world's population will be more than 6 billion, increasing by 90-100 million each year. About 95% of future demographic growth will take place in developing countries. The number of school age children is projected to increase from 940 million in 1980 to 1280 million by the year 2000. Under current labor force growth projections in developing countries, around 1.6 billion new jobs will have to be created between 1980 and 2025, with nearly 1 billion of them in Asia. Population often increases at a more rapid rate than agricultural growth. Food production per capita has declined in 70 developing countries. Much of the projected population increase will take place in environmentally fragile regions of the developing world. Population pressures contribute to deforestation, desertification, and scarcity of clean water. The United Nations Population Fund has estimated that in Asia over 43% of women not using family planning would like to postpone, space, or limit their childbearing. Over half of the world's couples of reproductive age are now using contraception. Family planning to postpone the first birth and to eliminate late child bearing would reduce both child loss and maternal illness and death. Both infant and maternal mortality are greater with higher order births. Reducing average family size is an effective way of reducing infant and maternal mortality. The World Bank has given high priority to population assistance, with large programs in Bangladesh, Egypt, India, Indonesia, the Philippines, and Thailand. Population assistance provided by the Australian International Development Assistance Bureau totaled about $4.5 million during 1989-90 and is expected to be about $8 million during 1991-92. Australia should increase the proportion of its development assistance budget devoted to population, and family planning programs should increase to around $26 million in line with other major donors

  9. Laws of valley growth

    NASA Astrophysics Data System (ADS)

    Seybold, Hansjoerg; Yi, Robert; Willenbring, Jane; Kirchner, James; Rothman, Daniel

    2015-04-01

    The question of how the channel heads advance has long been debated [1,2]. By studying a simplified setting - channels incised by re-emerging groundwater flow - we seek insight into the headward growth of channel networks, by combining theoretical modeling with field observations. A concept for how such seepage channel systems form was first proposed by T. Dunne in the early 1980s [2]. A small bulge in the sidewall of a stream focuses ground water flow. This results in a larger flux and therefore a higher erosion rate in this direction. Over time such small perturbations grow into newly formed streams, but how they do so and how erosion depends on the water flux is unclear. The theory of diffusive growth provides a theoretical framework to describe channelization in response to groundwater flow. For this system the underlying physical equations are well-defined, and numerical and analytical predictions can be obtained and tested in the field. If a stream advances at a rate v˜ q^η, where q is the discharge of ground water into the tip, theory predicts that η has to be smaller than a critical value η^star to obtain ramified networks [3]. We test this hypothesis by measuring erosion rates in a field site in the Florida Panhandle, which provides a natural laboratory to study channel incision by re-emerging groundwater flow [4]. Our theoretical network reconstruction yields tip growth rates which we can directly compare to observational rates obtained from cosmogenic 10Be measurements. This comparison of theory and observation allows us to verify the existence of a constitutive discharge-erosion relation, and to better characterize growth and competition of streams at the channel head. [1] Montgommery, D. R. and Dietrich, W. E. Where do channels begin?, Nature, 336, no. 6196 (1988): 232-234 [2] Dunne, T. Formation and controls of channel networks, Prog. Phys. Geogr., 4 (1980): 211-239 [3] Carleson, L. and Makarov, N. Laplacian path models, J. Anal. Math., 87, no. 1

  10. Cell Growth Enhancement

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Exogene Corporation uses advanced technologies to enhance production of bio-processed substances like proteins, antibiotics and amino acids. Among them are genetic modification and a genetic switch. They originated in research for Jet Propulsion Laboratory. Extensive experiments in cell growth through production of hemoglobin to improve oxygen supply to cells were performed. By improving efficiency of oxygen use by cells, major operational expenses can be reduced. Greater product yields result in decreased raw material costs and more efficient use of equipment. A broad range of applications is cited.

  11. Carbon nanotube growth density control

    NASA Technical Reports Server (NTRS)

    Delzeit, Lance D. (Inventor); Schipper, John F. (Inventor)

    2010-01-01

    Method and system for combined coarse scale control and fine scale control of growth density of a carbon nanotube (CNT) array on a substrate, using a selected electrical field adjacent to a substrate surface for coarse scale density control (by one or more orders of magnitude) and a selected CNT growth temperature range for fine scale density control (by multiplicative factors of less than an order of magnitude) of CNT growth density. Two spaced apart regions on a substrate may have different CNT growth densities and/or may use different feed gases for CNT growth.

  12. Dust Growth by RF Sputtering

    SciTech Connect

    Churton, B.; Samarian, A. A.; Coueedel, L.

    2008-09-07

    The effect of the dust particle growth by RF sputtering on glow discharge has been investigated. It has been found that the growth of dust particles modifies the electrical characteristics of the discharge. In particularly, the absolute value of the self-bias voltage decreases during the particle growth due to the electron losses on the dust particles. To find the correlation between the dust growth and the self bias evolution, dust particles have been collected at different times. The dust particle growth rate is found to be linear.

  13. FACET Emittance Growth

    SciTech Connect

    Frederico, J; Hogan, M.J.; Nosochkov, Y.; Litos, M.D.; Raubenheimer, T.; /SLAC

    2011-04-05

    FACET, the Facility for Advanced Accelerator and Experimental Tests, is a new facility being constructed in sector 20 of the SLAC linac primarily to study beam driven plasma wakefield acceleration. The FACET beamline consists of a chicane and final focus system to compress the 23 GeV, 3.2 nC electron bunches to {approx}20 {micro}m long and {approx}10 {micro}m wide. Simulations of the FACET beamline indicate the short-duration and large, 1.5% rms energy spread beams may suffer a factor of four emittance growth from a combination of chromaticity, incoherent synchrotron radiation (ISR), and coherent synchrotron radiation (CSR). Emittance growth is directly correlated to head erosion in plasma wakefield acceleration and is a limiting factor in single stage performance. Studies of the geometric, CSR, and ISR components are presented. Numerical calculation of the rms emittance can be overwhelmed by long tails in the simulated phase space distributions; more useful definitions of emittance are given. A complete simulation of the beamline is presented as well, which agrees with design specifications.

  14. Protein crystal growth

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Atomic force microscopy uses laser technology to reveal a defect, a double-screw dislocation, on the surface of this crystal of canavalin, a major source of dietary protein for humans and domestic animals. When a crystal grows, attachment kinetics and transport kinetics are competing for control of the molecules. As a molecule gets close to the crystal surface, it has to attach properly for the crystal to be usable. NASA has funded investigators to look at those attachment kinetics from a theoretical standpoint and an experimental standpoint. Dr. Alex McPherson of the University of California, Irvine, is one of those investigators. He uses X-ray diffraction and atomic force microscopy in his laboratory to answer some of the many questions about how protein crystals grow. Atomic force microscopy provides a means of looking at how individual molecules are added to the surface of growing protein crystals. This helps McPherson understand the kinetics of protein crystal growth. McPherson asks, How fast do crystals grow? What are the forces involved? Investigators funded by NASA have clearly shown that such factors as the level of supersaturation and the rate of growth all affect the habit [characteristic arrangement of facets] of the crystal and the defects that occur in the crystal.

  15. Chemical vapor deposition growth

    NASA Technical Reports Server (NTRS)

    Ruth, R. P.; Manasevit, H. M.; Campbell, A. G.; Johnson, R. E.; Kenty, J. L.; Moudy, L. A.; Shaw, G. L.; Simpson, W. I.; Yang, J. J.

    1978-01-01

    The objective was to investigate and develop chemical vapor deposition (CVD) techniques for the growth of large areas of Si sheet on inexpensive substrate materials, with resulting sheet properties suitable for fabricating solar cells that would meet the technical goals of the Low Cost Silicon Solar Array Project. The program involved six main technical tasks: (1) modification and test of an existing vertical-chamber CVD reactor system; (2) identification and/or development of suitable inexpensive substrate materials; (3) experimental investigation of CVD process parameters using various candidate substrate materials; (4) preparation of Si sheet samples for various special studies, including solar cell fabrication; (5) evaluation of the properties of the Si sheet material produced by the CVD process; and (6) fabrication and evaluation of experimental solar cell structures, using impurity diffusion and other standard and near-standard processing techniques supplemented late in the program by the in situ CVD growth of n(+)/p/p(+) sheet structures subsequently processed into experimental cells.

  16. Silicon Carbide Growth

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Andrew Trunek has focused on supporting the Sic team through the growth of Sic crystals, making observations and conducting research that meets the collective needs and requirements of the team while fulfilling program commitments. Cancellation of the Ultra Efficient Engine Technology (UEET) program has had a significant negative impact on resources and research goals. This report highlights advancements and achievements made with this cooperative agreement over the past year. NASA Glenn Research Center (GRC) continues to make advances in silicon carbide (SiC) research during the past year. Step free surfaces were used as substrates for the deposition of GaN epilayers that yielded very low dislocation densities. Defect free 3C- SiC was successfully nucleated on step free mesas and test diodes were fabricated. Web growth techniques were used to increase the usable surface area of dislocation free SiC by approximately equal to 40%. The greatest advancement has been attained on stepped surfaces of SiC. A metrology standard was developed using high temperature etching techniques titled "Nanometer Step Height Standard". This development culminated in being recognized for a 2004 R&D100 award and the process to produce the steps received a NASA Space Act award.

  17. Magnesium and fetal growth

    SciTech Connect

    Weaver, K.

    1988-01-01

    Fetal growth retardation and premature labor are major problems in perinatal medicine today and account for a great deal of the observed fetal morbidity. While the neonatal death rate has steadily declined over the past decade, there has been a lack of concommitant decrease in these two leading problems. Magnesium (Mg/sup ++/) plays a major role in both of these areas of concern. The fact that it is used as a treatment for premature labor has led investigators to look at low Mg/sup ++/ as a possible cause of this poorly understood phenomenon. The second major cause of small for gestational age infants is intrauterine growth retardation, a condition which may be of either fetal or maternal origin. In either case, Mg/sup ++/ may be implicated since it exerts a strong influence on the underlying pathophysiology of placental failure and maternal hypertension. Both of these conditions are mediated by vascular and platelet hyperactivity as well as by and increase in the ration of thromboxane to prostacyclin. Studies in both the human and animal species are beginning to show how Mg/sup ++/ interacts in these conditions to produce such a damaging fetal outcome. The recent use of Doppler velocimetry of the developing fetus has shown reduced fetal vascular and maternal uterine vascular compliance as early as 14 weeks of gestation in those who would be so affected.

  18. Probabilistic Mass Growth Uncertainties

    NASA Technical Reports Server (NTRS)

    Plumer, Eric; Elliott, Darren

    2013-01-01

    Mass has been widely used as a variable input parameter for Cost Estimating Relationships (CER) for space systems. As these space systems progress from early concept studies and drawing boards to the launch pad, their masses tend to grow substantially, hence adversely affecting a primary input to most modeling CERs. Modeling and predicting mass uncertainty, based on historical and analogous data, is therefore critical and is an integral part of modeling cost risk. This paper presents the results of a NASA on-going effort to publish mass growth datasheet for adjusting single-point Technical Baseline Estimates (TBE) of masses of space instruments as well as spacecraft, for both earth orbiting and deep space missions at various stages of a project's lifecycle. This paper will also discusses the long term strategy of NASA Headquarters in publishing similar results, using a variety of cost driving metrics, on an annual basis. This paper provides quantitative results that show decreasing mass growth uncertainties as mass estimate maturity increases. This paper's analysis is based on historical data obtained from the NASA Cost Analysis Data Requirements (CADRe) database.

  19. Geometrical approach to tumor growth.

    PubMed

    Escudero, Carlos

    2006-08-01

    Tumor growth has a number of features in common with a physical process known as molecular beam epitaxy. Both growth processes are characterized by the constraint of growth development to the body border, and surface diffusion of cells and particles at the growing edge. However, tumor growth implies an approximate spherical symmetry that makes necessary a geometrical treatment of the growth equations. The basic model was introduced in a former paper [C. Escudero, Phys. Rev. E 73, 020902(R) (2006)], and in the present work we extend our analysis and try to shed light on the possible geometrical principles that drive tumor growth. We present two-dimensional models that reproduce the experimental observations, and analyze the unexplored three-dimensional case, for which interesting conclusions on tumor growth are derived. PMID:17025466

  20. Chemical vapor deposition growth

    NASA Technical Reports Server (NTRS)

    Ruth, R. P.; Manasevit, H. M.; Kenty, J. L.; Moudy, L. A.; Simpson, W. I.; Yang, J. J.

    1976-01-01

    The chemical vapor deposition (CVD) method for the growth of Si sheet on inexpensive substrate materials is investigated. The objective is to develop CVD techniques for producing large areas of Si sheet on inexpensive substrate materials, with sheet properties suitable for fabricating solar cells meeting the technical goals of the Low Cost Silicon Solar Array Project. Specific areas covered include: (1) modification and test of existing CVD reactor system; (2) identification and/or development of suitable inexpensive substrate materials; (3) experimental investigation of CVD process parameters using various candidate substrate materials; (4) preparation of Si sheet samples for various special studies, including solar cell fabrication; (5) evaluation of the properties of the Si sheet material produced by the CVD process; and (6) fabrication and evaluation of experimental solar cell structures, using standard and near-standard processing techniques.

  1. Growth, children, and fractures.

    PubMed

    Jones, Graeme

    2004-09-01

    Fractures in childhood have long been considered an unavoidable consequence of growth. Studies in recent years have documented the epidemiology of these very common fractures and have also documented considerable variation by fracture type and from country to country. There have also been a number of studies aimed at identifying risk factors particularly for the most common distal forearm fracture. These studies have consistently associated bone mineral density with these fractures. Other possible risk factors include obesity, physical inactivity, sports, cola beverages, calcium intake, risk taking, and coordination. While prospective studies are required to confirm these risk factors, accumulating evidence now suggests that a substantial proportion of fractures in children are preventable. PMID:16036086

  2. Radiation growth of beryllium

    NASA Astrophysics Data System (ADS)

    Chakin, V. P.; Posevin, А. О.; Оbukhov, А. V.; Silantyev, P. P.

    2009-04-01

    Beryllium will be used as a neutron multiplier material in the present European HCPB (Helium Cooled Pebble Bed) blanket concept of the DEMO fusion reactor. Therefore, investigation of neutron irradiation influence on dimension stability of beryllium is very important. In this paper, the radiation damage of the TE-56 beryllium grade manufactured by hot extrusion was investigated. The beryllium samples were irradiated in the SM reactor at the temperatures of 70 °С and 200 °С up to neutron fluence of (1.3-14.2) 10 22 cm -2 (Е > 0.1 MeV). The measurements of the sample dimensions and density as well as microstructure examinations by X-rays and TEM were carried out. It was shown that superposition of two processes - radiation growth and anisotropic swelling occurs in beryllium under neutron irradiation.

  3. Elevated temperature crack growth

    NASA Technical Reports Server (NTRS)

    Yau, J. F.; Malik, S. N.; Kim, K. S.; Vanstone, R. H.; Laflen, J. H.

    1985-01-01

    The objective of the Elevated Temperature Crack Growth Project is to evaluate proposed nonlinear fracture mechanics methods for application to combustor liners of aircraft gas turbine engines. During the first year of this program, proposed path-independent (P-I) integrals were reviewed for such applications. Several P-I integrals were implemented into a finite-element postprocessor which was developed and verified as part of the work. Alloy 718 was selected as the analog material for use in the forthcoming experimental work. A buttonhead, single-edge notch specimen was designed and verified for use in elevated-temperature strain control testing with significant inelastic strains. A crack mouth opening displacement measurement device was developed for further use.

  4. Availability growth modeling

    SciTech Connect

    Wendelberger, J.R.

    1998-12-01

    In reliability modeling, the term availability is used to represent the fraction of time that a process is operating successfully. Several different definitions have been proposed for different types of availability. One commonly used measure of availability is cumulative availability, which is defined as the ratio of the amount of time that a system is up and running to the total elapsed time. During the startup phase of a process, cumulative availability may be treated as a growth process. A procedure for modeling cumulative availability as a function of time is proposed. Estimates of other measures of availability are derived from the estimated cumulative availability function. The use of empirical Bayes techniques to improve the resulting estimates is also discussed.

  5. Ureter growth and differentiation.

    PubMed

    Bohnenpoll, Tobias; Kispert, Andreas

    2014-12-01

    The mammalian ureter is a slender tube that connects the renal pelvis with the bladder. It allows the unidirectional movement of urine by means of a peristaltically active smooth muscle layer that together with fibroelastic material ensheathes a water-impermeable multilayered urothelium. The ureteric urothelium as well as the outer mesenchymal coat arise from undifferentiated precursor tissues, the distal ureteric bud and its surrounding mesenchyme, respectively. Specification, growth and differentiation of these ureteric precursor tissues are tightly linked to each other, and are highly integrated with those of the adjacent rudiments of kidney and bladder. Here, we review the current knowledge on the cellular mechanisms as well as the molecular players that guide development of the tissue architecture of the ureter and its peristalsis. PMID:25087982

  6. Growth control and ribosomopathies.

    PubMed

    Teng, Teng; Thomas, George; Mercer, Carol A

    2013-02-01

    Ribosome biogenesis and protein synthesis are two of the most energy consuming processes in a growing cell. Moreover, defects in their molecular components can alter the pattern of gene expression. Thus it is understandable that cells have developed a surveillance system to monitor the status of the translational machinery. Recent discoveries of causative mutations and deletions in genes linked to ribosome biogenesis have defined a group of similar pathologies termed ribosomopathies. Over the past decade, much has been learned regarding the relationship between growth control and ribosome biogenesis. The discovery of extra-ribosomal functions of several ribosome proteins and their regulation of p53 levels has provided a link from ribosome impairment to cell cycle regulation. Yet, evidence suggesting p53 and/or Hdm2 independent pathways also exists. In this review, we summarize recent advances in understanding the mechanisms underlying the pathologies of ribosomopathies and discuss the relationship between ribosome production and tumorigenesis. PMID:23490481

  7. Plant Growth Facility (PGF)

    NASA Technical Reports Server (NTRS)

    1998-01-01

    In a microgravity environment aboard the Space Shuttle Columbia Life and Microgravity Mission STS-78, compression wood formation and hence altered lignin deposition and cell wall structure, was induced upon mechanically bending the stems of the woody gymnosperms, Douglas fir (Pseudotsuga menziesii) and loblolly pine (Pinus taeda). Although there was significant degradation of many of the plant specimens in space-flight due to unusually high temperatures experienced during the mission, it seems evident that gravity had little or no effect on compression wood formation upon bending even in microgravity. Instead, it apparently results from alterations in the stress gradient experienced by the plant itself during bending under these conditions. This preliminary study now sets the stage for long-term plant growth experiments to determine whether compression wood formation can be induced in microgravity during phototropic-guided realignment of growing woody plant specimens, in the absence of any externally provided stress and strain.

  8. Monitoring cell growth.

    PubMed

    Strober, W

    2001-05-01

    This appendix provides two protocols for monitoring cell growth. Counting cells using a hemacytometer is tedious but it allows one to effectively distinguish live cells from dead cells (using Trypan Blue exclusion). In addition, this procedure is less subject to errors due to cell clumping or heterogeneity of cell size. The use of an electronic cell counter is quicker and easier than counting cells using a hemacytometer. However, an electronic cell counter as currently constructed does not distinguish live from dead cells in a reliable fashion and is subject to error due to the presence of cell clumps. Overall, the electronic cell counter is best reserved for repetitive and rapid counting of fresh peripheral blood cells and should be used with caution when counting cell populations derived from tissues. PMID:18432653

  9. Autocatalysis during fullerene growth

    SciTech Connect

    Eggen, B.R.; Heggie, M.I.; Jungnickel, G.; Latham, C.D.; Jones, R.; Briddon, P.R.

    1996-04-05

    Total energy calculations with a local spin density functional have been applied to the Stone-Wales transformation in fullerene (C{sub 60}). In the formation of the almost exclusively observed I{sub h} isomer of C{sub 60} with isolated pentagons, the final transformation must be from a C{sub 2v} isomer with two pentagon pairs. It was found that the energy barrier for this rearrangement was substantially reduced in the presence of an extra carbon atom. Such atoms were found to bind loosely, preferentially to regions in which there were paired pentagons. Pentagon rearrangements, which are necessary steps in the growth of fullerenes, may therefore result from autocatalysis by carbon.

  10. Pattern, Growth and Control

    PubMed Central

    Lander, Arthur D.

    2011-01-01

    The view of biology as goal-directed engineering has deep historical roots in developmental biology, a field currently benefitting from an influx of ideas and methods from systems biology. Systems biology draws on non-biological paradigms to explain developmental mechanisms of control, the specific type of regulation that achieves or maintains a desired end. This review highlights some of the current efforts designed to elucidate basic design principles underlying the engineering objectives of robustness, precision, and scaling that are required during developmental control of growth and pattern formation. Examples from vertebrate and invertebrate development are used to illustrate general principles including the value of integral feedback in achieving set-point control; the usefulness of self-organizing behavior; the importance of recognizing and appropriately handling noise; and the No Free Lunch theory. Through the examination of such principles, systems biology offers a functional framework to make sense of the mechanistic complexity of organismal development. PMID:21414486

  11. MCT crystal growth

    NASA Technical Reports Server (NTRS)

    Baird, James K.

    1988-01-01

    Convection and segregation in directional solidification and crystal growth by the Bridgman-Stockbarger technique are traditionally treated by assuming axisymmetric thermal condition on the ampoule wall. It is, however, difficult to achieve such a condition in an experimental setup. Any deviation from an axisymmetric temperature field on the wall of a vertical ampoule represents a horizontal temperature gradient. The horizontal density gradient that results from thermal expansion in the melt under this condition must lead on earth to some buoyance-driven convection, no matter what the axial (vertical) temperature distribution that is imposed on the melt. The magnitude of such convective flows for conditions representative of the MSFC mercury-cadmium-telluride (MCT) Bridgman setup is studied.

  12. Capital Growth Paths of the Neoclassical Growth Model

    PubMed Central

    Takahashi, Taro

    2012-01-01

    This paper derives the first-order approximated paths of both types of capital in the two-capital neoclassical growth model. The derived capital growth paths reveal that the short-run growth effect of capital injection differs considerably depending on which type of capital is enhanced. This result demonstrates the importance of well-targeted capital enhancement programs such as public sector projects and foreign aid. PMID:23185344

  13. Growth outside the core.

    PubMed

    Zook, Chris; Allen, James

    2003-12-01

    Growth in an adjacent market is tougher than it looks; three-quarters of the time, the effort fails. But companies can change those odds dramatically. Results from a five-year study of corporate growth conducted by Bain & Company reveal that adjacency expansion succeeds only when built around strong core businesses that have the potential to become market leaders. And the best place to look for adjacency opportunities is inside a company's strongest customers. The study also found that the most successful companies were able to consistently, profitably outgrow their rivals by developing a formula for pushing out the boundaries of their core businesses in predictable, repeatable ways. Companies use their repeatability formulas to expand into any number of adjacencies. Some companies make repeated geographic moves, as Vodafone has done in expanding from one geographic market to another over the past 13 years, building revenues from $1 billion in 1990 to $48 billion in 2003. Others apply a superior business model to new segments. Dell, for example, has repeatedly adapted its direct-to-customer model to new customer segments and new product categories. In other cases, companies develop hybrid approaches. Nike executed a series of different types of adjacency moves: it expanded into adjacent customer segments, introduced new products, developed new distribution channels, and then moved into adjacent geographic markets. The successful repeaters in the study had two common characteristics. First, they were extraordinarily disciplined, applying rigorous screens before they made an adjacency move. This discipline paid off in the form of learning curve benefits, increased speed, and lower complexity. And second, in almost all cases, they developed their repeatable formulas by studying their customers and their customers' economics very, very carefully. PMID:14712545

  14. Gravity and Skeletal Growth

    NASA Technical Reports Server (NTRS)

    Morey-Holton, Emily; Turner, Russell T.

    1999-01-01

    Two simultaneous experiments were performed using 5-week-old male Sprague Dawley rats; in one study, the rats were flown in low earth orbit; in the other study, the hindlimbs of the growing rats were elevated to prevent weight bearing. Following 9 d of unloading, weight bearing was restored for 4, 28, and 76 hrs. Afterwards, additional hindlimb unloading experiments were performed to evaluate the skeletal response to 0, 2, 4, 6, 8, 10, 12, 16, and 24 hrs of restored weight bearing following 7 d of unloading. Cancellous and cortical bone histomorphometry were evaluated in the left tibia at the proximal metaphysis and in the left femur at mid-diaphysis, respectively. Steady-state mRNA levels for bone matrix proteins and skeletal signaling peptides were determined in total cellular RNA extracted from trabeculae from the right proximal tibiametaphysis and periosteum from the right femur. Spaceflight and hindlimb unloading each resulted in cancellous osteopenia, as well as a tendency towards decreased periosteal bone formation. Both models for skeletal unloading resulted in site specific reductions in mRNA levels for transforming growth factor-beta (sub 1) (TGF-beta) osteocalcin (OC), and prepro-alpha (I) subunit of type 1 collagen (collagen) and little or no changes in mRNA levels for glyceraldehyde-3-phosphate dehydrogenase (GAP) and insulin-like growth factor I (IGF-I). Restoration of normal weight bearing resulted in transient increases in mRNA levels for the bone matrix proteins and TGF-beta in the proximal metaphysis and periosteum and no changes in either GAP or IGF-I mRNA levels. The timecourse for the response differed between the two skeletal compartments; the tibial metaphysis responded much more quickly to reloading. These results suggest that the skeletal adaptation to acute physiological changes in mechanical usage are mediated, in part, by changes in mRNA levels for bone matrix proteins and TGF-beta.

  15. Thermodynamics of firms' growth

    PubMed Central

    Zambrano, Eduardo; Hernando, Alberto; Hernando, Ricardo; Plastino, Angelo

    2015-01-01

    The distribution of firms' growth and firms' sizes is a topic under intense scrutiny. In this paper, we show that a thermodynamic model based on the maximum entropy principle, with dynamical prior information, can be constructed that adequately describes the dynamics and distribution of firms' growth. Our theoretical framework is tested against a comprehensive database of Spanish firms, which covers, to a very large extent, Spain's economic activity, with a total of 1 155 142 firms evolving along a full decade. We show that the empirical exponent of Pareto's law, a rule often observed in the rank distribution of large-size firms, is explained by the capacity of economic system for creating/destroying firms, and that can be used to measure the health of a capitalist-based economy. Indeed, our model predicts that when the exponent is larger than 1, creation of firms is favoured; when it is smaller than 1, destruction of firms is favoured instead; and when it equals 1 (matching Zipf's law), the system is in a full macroeconomic equilibrium, entailing ‘free’ creation and/or destruction of firms. For medium and smaller firm sizes, the dynamical regime changes, the whole distribution can no longer be fitted to a single simple analytical form and numerical prediction is required. Our model constitutes the basis for a full predictive framework regarding the economic evolution of an ensemble of firms. Such a structure can be potentially used to develop simulations and test hypothetical scenarios, such as economic crisis or the response to specific policy measures. PMID:26510828

  16. Thermodynamics of firms' growth.

    PubMed

    Zambrano, Eduardo; Hernando, Alberto; Fernández Bariviera, Aurelio; Hernando, Ricardo; Plastino, Angelo

    2015-11-01

    The distribution of firms' growth and firms' sizes is a topic under intense scrutiny. In this paper, we show that a thermodynamic model based on the maximum entropy principle, with dynamical prior information, can be constructed that adequately describes the dynamics and distribution of firms' growth. Our theoretical framework is tested against a comprehensive database of Spanish firms, which covers, to a very large extent, Spain's economic activity, with a total of 1,155,142 firms evolving along a full decade. We show that the empirical exponent of Pareto's law, a rule often observed in the rank distribution of large-size firms, is explained by the capacity of economic system for creating/destroying firms, and that can be used to measure the health of a capitalist-based economy. Indeed, our model predicts that when the exponent is larger than 1, creation of firms is favoured; when it is smaller than 1, destruction of firms is favoured instead; and when it equals 1 (matching Zipf's law), the system is in a full macroeconomic equilibrium, entailing 'free' creation and/or destruction of firms. For medium and smaller firm sizes, the dynamical regime changes, the whole distribution can no longer be fitted to a single simple analytical form and numerical prediction is required. Our model constitutes the basis for a full predictive framework regarding the economic evolution of an ensemble of firms. Such a structure can be potentially used to develop simulations and test hypothetical scenarios, such as economic crisis or the response to specific policy measures. PMID:26510828

  17. Estimation of alga growth stage and lipid content growth rate

    NASA Technical Reports Server (NTRS)

    Embaye, Tsegereda N. (Inventor); Trent, Jonathan D. (Inventor)

    2012-01-01

    Method and system for estimating a growth stage of an alga in an ambient fluid. Measured light beam absorption or reflection values through or from the alga and through an ambient fluid, in each of two or more wavelength sub-ranges, are compared with reference light beam absorption values for corresponding wavelength sub-ranges for in each alga growth stage to determine (1) which alga growth stage, if any, is more likely and (2) whether estimated lipid content of the alga is increasing or has peaked. Alga growth is preferably terminated when lipid content has approximately reached a maximum value.

  18. Growth factor involvement in tension-induced skeletal muscle growth

    NASA Technical Reports Server (NTRS)

    Vandenburgh, H. H.

    1987-01-01

    Muscle tissue culture techniques were developed to grow skeletal myofibers which differentiate into more adult-like myofibers. Mechanical simulation studies of these muscle cells in a newly developed mechanical cell simulator can now be performed to study growth processes in skeletal muscle. Conditions in the mechanical cell simulator were defined where mechanical activity can either prevent muscle wasting or stimulate muscle growth. The role of endogenous and exogenous growth factors in tension-induced muscle growth is being investigated under the defined conditions of tissue culture.

  19. Transforming growth factor-beta 1 and fibroblast growth factors in rat growth plate.

    PubMed

    Jingushi, S; Scully, S P; Joyce, M E; Sugioka, Y; Bolander, M E

    1995-09-01

    Chondrocytes in the growth plate progress in an orderly fashion from resting through proliferating to hypertrophic cells. In the region of hypertrophic chondrocytes, the cartilage is invaded by capillary loops and endochondral ossification is initiated. It is currently believed that growth factors may regulate the proliferation and maturation of chondrocytes and the synthesis of extracellular matrix in the growth plate. The ordered sequence of proliferation and differentiation observed in the growth plate provides a unique opportunity to study the role of acidic fibroblast growth factor, basic fibroblast growth factor, and transforming growth factor-beta 1 in the regulation of these processes. In this study, expression of the mRNA of these growth factors was examined using total RNA extracted from the physis and epiphysis of rat tibias. Transforming growth factor-beta 1 mRNA was detected by Northern hybridization. Expression of the genes encoding acidic and basic fibroblast growth factors was demonstrated by polymerase chain reaction amplification. In addition, using polyclonal antibodies against these growth factors, we localized them by immunohistochemical analysis. Strong intracellular staining with a predominantly nuclear pattern was observed in chondrocytes from the proliferating and upper hypertrophic zones. In contrast, chondrocytes in the resting zone stained only faintly for the presence of these growth factors. Some chondrocytes in the resting zone adjacent to the proliferating zone stained with these antibodies, and the antibodies also stained cells in the zone of Ranvier, which regulates latitudinal bone growth. Lastly, the location of transforming growth factor-beta 1 was examined further with use of a polyclonal antipeptide antibody specific for its extracellular epitope.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7472755

  20. Growth Failure in Children with Kidney Disease

    MedlinePlus

    ... Language URL Growth Failure in Children with Chronic Kidney Disease Page Content On this page: What is growth ... What is growth failure in children with chronic kidney disease (CKD)? Growth failure is a complication of CKD ...

  1. Protein crystal growth in microgravity

    NASA Technical Reports Server (NTRS)

    Rosenblum, William M.; Delucas, Lawrence J.; Wilson, William W.

    1989-01-01

    Major advances have been made in several of the experimental aspects of protein crystallography, leaving protein crystallization as one of the few remaining bottlenecks. As a result, it has become important that the science of protein crystal growth is better understood and that improved methods for protein crystallization are developed. Preliminary experiments with both small molecules and proteins indicate that microgravity may beneficially affect crystal growth. For this reason, a series of protein crystal growth experiments using the Space Shuttle was initiated. The preliminary space experiments were used to evolve prototype hardware that will form the basis for a more advanced system that can be used to evaluate effects of gravity on protein crystal growth. Various optical techniques are being utilized to monitor the crystal growth process from the incipient or nucleation stage and throughout the growth phase. The eventual goal of these studies is to develop a system which utilizes optical monitoring for dynamic control of the crystallization process.

  2. Growth factor involvement in tension-induced skeletal muscle growth

    NASA Technical Reports Server (NTRS)

    Vandenburgh, Herman H.

    1993-01-01

    Long-term manned space travel will require a better understanding of skeletal muscle atrophy which results from microgravity. Astronaut strength and dexterity must be maintained for normal mission operations and for emergency situations. Although exercise in space slows the rate of muscle loss, it does not prevent it. A biochemical understanding of how gravity/tension/exercise help to maintain muscle size by altering protein synthesis and/or degradation rate should ultimately allow pharmacological intervention to prevent muscle atrophy in microgravity. The overall objective is to examine some of the basic biochemical processes involved in tension-induced muscle growth. With an experimental in vitro system, the role of exogenous and endogenous muscle growth factors in mechanically stimulated muscle growth are examined. Differentiated avian skeletal myofibers can be 'exercised' in tissue culture using a newly developed dynamic mechanical cell stimulator device which simulates different muscle activity patterns. Patterns of mechanical activity which significantly affect muscle growth and metabolic characteristics were found. Both exogenous and endogenous growth factors are essential for tension-induced muscle growth. Exogenous growth factors found in serum, such as insulin, insulin-like growth factors, and steroids, are important regulators of muscle protein turnover rates and mechanically-induced muscle growth. Endogenous growth factors are synthesized and released into the culture medium when muscle cells are mechanically stimulated. At least one family of mechanically induced endogenous factors, the prostaglandins, help to regulate the rates of protein turnover in muscle cells. Endogenously synthesized IGF-1 is another. The interaction of muscle mechanical activity and these growth factors in the regulation of muscle protein turnover rates with our in vitro model system is studied.

  3. Stochastic roots of growth phenomena

    NASA Astrophysics Data System (ADS)

    De Lauro, E.; De Martino, S.; De Siena, S.; Giorno, V.

    2014-05-01

    We show that the Gompertz equation describes the evolution in time of the median of a geometric stochastic process. Therefore, we induce that the process itself generates the growth. This result allows us further to exploit a stochastic variational principle to take account of self-regulation of growth through feedback of relative density variations. The conceptually well defined framework so introduced shows its usefulness by suggesting a form of control of growth by exploiting external actions.

  4. Protein crystal growth in space

    NASA Technical Reports Server (NTRS)

    Bugg, C. E.; Clifford, D. W.

    1987-01-01

    The advantages of protein crystallization in space, and the applications of protein crystallography to drug design, protein engineering, and the design of synthetic vaccines are examined. The steps involved in using protein crystallography to determine the three-dimensional structure of a protein are discussed. The growth chamber design and the hand-held apparatus developed for protein crystal growth by vapor diffusion techniques (hanging-drop method) are described; the experimental data from the four Shuttle missions are utilized to develop hardware for protein crystal growth in space and to evaluate the effects of gravity on protein crystal growth.

  5. Uncertainties in debris growth predictions

    SciTech Connect

    McKnight, D.S. )

    1991-01-10

    The growth of artificial space debris in Earth orbit may pose a significant hazard to satellites in the future though the collision hazard to operational spacecraft is presently manageable. The stability of the environment is dependent on the growth of debris from satellite deployment, mission operations and fragmentation events. Growth trends of the trackable on-orbit population are investigated highlighting the complexities and limitations of using the data that supports this modeling. The debris produced by breakup events may be a critical aspect of the present and future environment. As a result, growth predictions produced using existing empirically-based models may have large, possibly even unacceptable, uncertainties.

  6. Growth hormone signaling pathways.

    PubMed

    Carter-Su, Christin; Schwartz, Jessica; Argetsinger, Lawrence S

    2016-06-01

    Over 20years ago, our laboratory showed that growth hormone (GH) signals through the GH receptor-associated tyrosine kinase JAK2. We showed that GH binding to its membrane-bound receptor enhances binding of JAK2 to the GHR, activates JAK2, and stimulates tyrosyl phosphorylation of both JAK2 and GHR. The activated JAK2/GHR complex recruits a variety of signaling proteins, thereby initiating multiple signaling pathways and cellular responses. These proteins and pathways include: 1) Stat transcription factors implicated in the expression of multiple genes, including the gene encoding insulin-like growth factor 1; 2) Shc adapter proteins that lead to activation of the grb2-SOS-Ras-Raf-MEK-ERK1,2 pathway; 3) insulin receptor substrate proteins implicated in the phosphatidylinositol-3-kinase and Akt pathway; 4) signal regulatory protein α, a transmembrane scaffold protein that recruits proteins including the tyrosine phosphatase SHP2; and 5) SH2B1, a scaffold protein that can activate JAK2 and enhance GH regulation of the actin cytoskeleton. Our recent work has focused on the function of SH2B1. We have shown that SH2B1β is recruited to and phosphorylated by JAK2 in response to GH. SH2B1 localizes to the plasma membrane, cytoplasm and focal adhesions; it also cycles through the nucleus. SH2B1 regulates the actin cytoskeleton and promotes GH-dependent motility of RAW264.7 macrophages. Mutations in SH2B1 have been found in humans exhibiting severe early-onset childhood obesity and insulin resistance. These mutations impair SH2B1 enhancement of GH-induced macrophage motility. As SH2B1 is expressed ubiquitously and is also recruited to a variety of receptor tyrosine kinases, our results raise the possibility that effects of SH2B1 on the actin cytoskeleton in various cell types, including neurons, may play a role in regulating body weight. PMID:26421979

  7. Minimizing Public Costs of Residential Growth. Coping With Growth.

    ERIC Educational Resources Information Center

    Weber, Bruce; Beck, Richard

    Rapid residential growth in rural areas or on the fringes of urban areas brings both costs and benefits. Seven factors determine whether new homes and subdivisions generate more revenues than expenditures. Local governments can substantially influence four of these seven factors in order to reduce the public costs of residential growth. Less…

  8. Growth factor involvement in tension-induced skeletal muscle growth

    NASA Technical Reports Server (NTRS)

    Vandenburgh, Herman W.

    1987-01-01

    New muscle tissue culture techniques were developed to grow embryonic skeletal myofibers which are able to differentiate into more adultlike myofibers. Studies on mechanical simulation of cultured muscle cell growth will now be more directly applicable to mechanically-induced growth in adult muscle, and lead to better models for understanding muscle tissue atrophy caused by disuse in the microgravity of space.

  9. On growth rate hysteresis and catastrophic crystal growth

    NASA Astrophysics Data System (ADS)

    Ferreira, Cecília; Rocha, Fernando A.; Damas, Ana M.; Martins, Pedro M.

    2013-04-01

    Different crystal growth rates as supersaturation is increasing or decreasing in impure media is a phenomenon called growth rate hysteresis (GRH) that has been observed in varied systems and applications, such as protein crystallization or during biomineralization. We have recently shown that the transient adsorption of impurities onto newly formed active sites for growth (or kinks) is sensitive to the direction and rate of supersaturation variation, thus providing a possible explanation for GRH [6]. In the present contribution, we expand on this concept by deriving the analytical expressions for transient crystal growth based on the energetics of growth hillock formation and kink occupation by impurities. Two types of GRH results are described according to the variation of kink density with supersaturation: for nearly constant density, decreasing or increasing supersaturation induce, respectively, growth promoting or inhibiting effects relative to equilibrium conditions. This is the type of GRH measured by us during the crystallization of egg-white lysozyme. For variable kink density, slight changes in the supersaturation level may induce abrupt variations in the crystal growth rate. Different literature examples of this so-called 'catastrophic' crystal growth are discussed in terms of their fundamental consequences.

  10. Soybean Growth Aboard ISS

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This is a photo of soybeans growing in the Advanced Astroculture (ADVASC) Experiment aboard the International Space Station (ISS). The ADVASC experiment was one of the several new experiments and science facilities delivered to the ISS by Expedition Five aboard the Space Shuttle Orbiter Endeavor STS-111 mission. An agricultural seed company will grow soybeans in the ADVASC hardware to determine whether soybean plants can produce seeds in a microgravity environment. Secondary objectives include determination of the chemical characteristics of the seed in space and any microgravity impact on the plant growth cycle. Station science will also be conducted by the ever-present ground crew, with a new cadre of controllers for Expedition Five in the ISS Payload Operations Control Center (POCC) at NASA's Marshall Space Flight Center in Huntsville, Alabama. Controllers work in three shifts around the clock, 7 days a week, in the POCC, the world's primary science command post for the Space Station. The POCC links Earth-bound researchers around the world with their experiments and crew aboard the Space Station.

  11. Quartz crystal growth

    DOEpatents

    Baughman, Richard J.

    1992-01-01

    A process for growing single crystals from an amorphous substance that can undergo phase transformation to the crystalline state in an appropriate solvent. The process is carried out in an autoclave having a lower dissolution zone and an upper crystallization zone between which a temperature differential (.DELTA.T) is maintained at all times. The apparatus loaded with the substance, solvent, and seed crystals is heated slowly maintaining a very low .DELTA.T between the warmer lower zone and cooler upper zone until the amorphous substance is transformed to the crystalline state in the lower zone. The heating rate is then increased to maintain a large .DELTA.T sufficient to increase material transport between the zones and rapid crystallization. .alpha.-Quartz single crystal can thus be made from fused quartz in caustic solvent by heating to 350.degree. C. stepwise with a .DELTA.T of 0.25.degree.-3.degree. C., increasing the .DELTA.T to about 50.degree. C. after the fused quartz has crystallized, and maintaining these conditions until crystal growth in the upper zone is completed.

  12. Total immersion crystal growth

    NASA Technical Reports Server (NTRS)

    Morrison, Andrew D. (Inventor)

    1987-01-01

    Crystals of wide band gap materials are produced by positioning a holder receiving a seed crystal at the interface between a body of molten wide band gap material and an overlying layer of temperature-controlled, encapsulating liquid. The temperature of the layer decreases from the crystallization temperature of the crystal at the interface with the melt to a substantially lower temperature at which formation of crystal defects does not occur, suitably a temperature of 200 to 600 C. After initiation of crystal growth, the leading edge of the crystal is pulled through the layer until the leading edge of the crystal enters the ambient gas headspace which may also be temperature controlled. The length of the column of liquid encapsulant may exceed the length of the crystal such that the leading edge and trailing edge of the crystal are both simultaneously with the column of the crystal. The crystal can be pulled vertically by means of a pulling-rotation assembly or horizontally by means of a low-angle withdrawal mechanism.

  13. Problems of rapid growth.

    PubMed

    Kim, T D

    1980-01-01

    South Korea's export-oriented development strategy has achieved a remarkable growth record, but it has also brought 2 different problems: 1) since the country's exports accounted for about 1% of total world export volume, the 1st world has become fearful about Korea's aggressive export drive; and 2) the fact that exports account for over 30% of its total gross national product (GNP) exposes the vulnerability of South Korea's economy itself. South Korea continues to be a poor nation, although it is rated as 1 of the most rapidly growing middle income economies. A World Bank 1978 report shows Korea to be 28th of 58 middle income countries in terms of per capita GNP in 1976. Of 11 newly industrializing countries (NIC), 5 in the European continent are more advanced than the others. A recent emphasis on the basic human needs approach has tended to downgrade the concept of GNP. Korea has only an abundant labor force and is without any natural resources. Consequently, Korea utilized an export-oriented development strategy. Oil requirements are met with imports, and almost all raw materials to be processed into exportable products must be imported. To pay import bills Korea must export and earn foreign exchange. It must be emphasized that foreign trade must always be 2-way traffic. In order to export more to middle income countries like Korea, the countries of the 1st world need to ease their protectionist measures against imports from developing countries. PMID:12336527

  14. Nutritional catch-up growth.

    PubMed

    Gat-Yablonski, Galia; Pando, Rakefet; Phillip, Moshe

    2013-01-01

    Malnutrition, marked by variant nutrient deficiencies, is considered a leading cause of stunted growth worldwide. In developing countries, malnutrition is caused mainly by food shortage and infectious diseases. Malnutrition may also be found in the developed world, where it is due mostly to prematurity, chronic diseases, and anorexia nervosa. In most cases, when food consumption is corrected, spontaneous catch-up (CU) growth occurs. However, CU growth is not always complete, leading to growth deficits. Therefore, it is important to understand the mechanisms that govern this process. Using a rat model of food restriction followed by refeeding, we established a nutrition-induced CU growth model. Levels of leptin and insulin-like growth factor-1 were found to significantly decrease when food was restricted and to increase already 1 day after refeeding. Gene expression analysis of the growth plate revealed that food restriction specifically affects transcription factors such as the hypoxia inducible factor-1 and its downstream targets on the one hand, and global gene expression, indicating epigenetic regulation, on the other. Food restriction also reduced the level of several microRNAs, including the chondrocyte-specific miR-140, which led to an increase in its target, SIRT1, a class III histone deacetylase. These findings may explain the global changes in gene expression observed under nutritional manipulation. We suggest that multiple levels of regulation, including transcription factors, epigenetic mechanisms, and microRNAs respond to nutritional cues and offer a possible explanation for some of the effects of food restriction on epiphyseal growth plate growth. The means whereby these components sense changes in nutritional status are still unknown. Deciphering the role of epigenetic regulation in growth may pave the way for the development of new treatments for children with growth disorders. PMID:23428685

  15. Growth of a Pine Tree

    ERIC Educational Resources Information Center

    Rollinson, Susan Wells

    2012-01-01

    The growth of a pine tree is examined by preparing "tree cookies" (cross-sectional disks) between whorls of branches. The use of Christmas trees allows the tree cookies to be obtained with inexpensive, commonly available tools. Students use the tree cookies to investigate the annual growth of the tree and how it corresponds to the number of whorls…

  16. Forces Influencing Rural Community Growth.

    ERIC Educational Resources Information Center

    Rainey, Kenneth D.

    The paper briefly focuses on two questions: Can the recent growth trend be expected to continue into the future? and What does this imply as far as public policy and programs are concerned? Statistics on growth in the seventies suggest three possibilities: a change in the functions of metropolitan and nonmetropolitan areas; the decline of the city…

  17. Teaching "The Limits to Growth"

    ERIC Educational Resources Information Center

    Williamson, Nancy E.

    1974-01-01

    Classroom use of "Limits to Growth" and related materials to integrate a course on population growth, food problems, resource problems and environmental issues is described in a journal available from the Foreign Area Materials Center, State Ed. Dept., 60 East 42nd St., New York, N. Y. 10017. (JH)

  18. Numerical Simulation of Nanostructure Growth

    NASA Technical Reports Server (NTRS)

    Hwang, Helen H.; Bose, Deepak; Govindan, T. R.; Meyyappan, M.

    2004-01-01

    Nanoscale structures, such as nanowires and carbon nanotubes (CNTs), are often grown in gaseous or plasma environments. Successful growth of these structures is defined by achieving a specified crystallinity or chirality, size or diameter, alignment, etc., which in turn depend on gas mixture ratios. pressure, flow rate, substrate temperature, and other operating conditions. To date, there has not been a rigorous growth model that addresses the specific concerns of crystalline nanowire growth, while demonstrating the correct trends of the processing conditions on growth rates. Most crystal growth models are based on the Burton, Cabrera, and Frank (BCF) method, where adatoms are incorporated into a growing crystal at surface steps or spirals. When the supersaturation of the vapor is high, islands nucleate to form steps, and these steps subsequently spread (grow). The overall bulk growth rate is determined by solving for the evolving motion of the steps. Our approach is to use a phase field model to simulate the growth of finite sized nanowire crystals, linking the free energy equation with the diffusion equation of the adatoms. The phase field method solves for an order parameter that defines the evolving steps in a concentration field. This eliminates the need for explicit front tracking/location, or complicated shadowing routines, both of which can be computationally expensive, particularly in higher dimensions. We will present results demonstrating the effect of process conditions, such as substrate temperature, vapor supersaturation, etc. on the evolving morphologies and overall growth rates of the nanostructures.

  19. Fundamental Cycles of Cognitive Growth.

    ERIC Educational Resources Information Center

    Pegg, John

    Over recent years, various theories have arisen to explain and predict cognitive development in mathematics education. We focus on an underlying theme that recurs throughout such theories: a fundamental cycle of growth in the learning of specific concepts, which we frame within broader global theories of individual cognitive growth. Our purpose is…

  20. The Growth of Tense Productivity

    ERIC Educational Resources Information Center

    Rispoli, Matthew; Hadley, Pamela A.; Holt, Janet K.

    2009-01-01

    Purpose: This study tests empirical predictions of a maturational model for the growth of tense in children younger than 36 months using a type-based productivity measure. Method: Caregiver-child language samples were collected from 20 typically developing children every 3 months from 21 to 33 months of age. Growth in the productivity of tense…

  1. Physical vapor transport crystal growth

    NASA Technical Reports Server (NTRS)

    Yoel, Dave W.; Anderson, Elmer; Wu, Maw-Kuen; Cheng, H. Y.

    1987-01-01

    The goals of this research are two-fold: to study effective means of growing ZnSe crystals of good optical quality and to determine the advantages of growing such crystals in microgravity. As of this date the optimal conditions for crystal growth have not been determined. However, successful growth runs were made in two furnances and the results are given.

  2. U.S. Population Growth.

    ERIC Educational Resources Information Center

    Dillner, Harry

    This autoinstructional lesson deals with the study of man and his environment. No previous experience or learning in this field is required. Emphasis is placed on analysis of population growth and the impact population growth and trends have on natural resource depletion. The behavioral objectives (five) are listed. The study guide for the…

  3. Population Growth: Crisis and Challenge.

    ERIC Educational Resources Information Center

    Beaton, John R., Ed.; Doberenz, Alexander R., Ed.

    The proceedings of this first annual symposium on population growth considers the consequences of this growth, along with possible means of regulation. Topics of speeches include: Population Outlook in Asia (Irene Taeuber); Malnutrition is a Problem of Ecology (Paul Gyorgy); The Leisure Explosion (E. H. Storey); Effects of Pollution on Population…

  4. Growth curves for Laron syndrome.

    PubMed Central

    Laron, Z; Lilos, P; Klinger, B

    1993-01-01

    Growth curves for children with Laron syndrome were constructed on the basis of repeated measurements made throughout infancy, childhood, and puberty in 24 (10 boys, 14 girls) of the 41 patients with this syndrome investigated in our clinic. Growth retardation was already noted at birth, the birth length ranging from 42 to 46 cm in the 12/20 available measurements. The postnatal growth curves deviated sharply from the normal from infancy on. Both sexes showed no clear pubertal spurt. Girls completed their growth between the age of 16-19 years to a final mean (SD) height of 119 (8.5) cm whereas the boys continued growing beyond the age of 20 years, achieving a final height of 124 (8.5) cm. At all ages the upper to lower body segment ratio was more than 2 SD above the normal mean. These growth curves constitute a model not only for primary, hereditary insulin-like growth factor-I (IGF-I) deficiency (Laron syndrome) but also for untreated secondary IGF-I deficiencies such as growth hormone gene deletion and idiopathic congenital isolated growth hormone deficiency. They should also be useful in the follow up of children with Laron syndrome treated with biosynthetic recombinant IGF-I. PMID:8333769

  5. A Simple Plant Growth Analysis.

    ERIC Educational Resources Information Center

    Oxlade, E.

    1985-01-01

    Describes the analysis of dandelion peduncle growth based on peduncle length, epidermal cell dimensions, and fresh/dry mass. Methods are simple and require no special apparatus or materials. Suggests that limited practical work in this area may contribute to students' lack of knowledge on plant growth. (Author/DH)

  6. Chemical Control of Plant Growth.

    ERIC Educational Resources Information Center

    Agricultural Research Center (USDA), Beltsville, MD.

    Seven experiments are presented in this Science Study Aid to help students investigate the control of plant growth with chemicals. Plant growth regulators, weed control, and chemical pruning are the topics studied in the experiments which are based on investigations that have been and are being conducted at the U. S. Agricultural Research Center,…

  7. Cessation of growth in crystals

    NASA Astrophysics Data System (ADS)

    Falcón Rodríguez, C.; Aguilera Morales, S.; Falcón Rodríguez, F.

    2000-01-01

    A mathematical model that explains the cessation of growth of protein crystals as a consequence of the increment of bond weakness between adjacent protein molecules is presented. It is assumed that the main factor increasing the bond weakness is the concentration of precipitating salts generally used in protein crystal growth practice.

  8. Automated protein crystal growth facility

    NASA Technical Reports Server (NTRS)

    Donald, Stacey

    1994-01-01

    A customer for the protein crystal growth facility fills the specially designed chamber with the correct solutions, fills the syringes with their quenching solutions, and submits the data needed for the proper growth of their crystal. To make sure that the chambers and syringes are filled correctly, a NASA representative may assist the customer. The data needed is the approximate growth time, the growth temperature, and the desired crystal size, but this data can be changed anytime from the ground, if needed. The chambers are gathered and placed into numbered slots in special drawers. Then, data is entered into a computer for each of the chambers. Technicians map out when each chamber's growth should be activated so that all of the chambers have enough time to grow. All of this data is up-linked to the space station when the previous growth session is over. Anti-vibrational containers need to be constructed for the high forces encountered during the lift off and the landing of the space shuttle, and though our team has not designed these containers, we do not feel that there is any reason why a suitable one could not be made. When the shuttle reaches the space station, an astronaut removes a drawer of quenched chambers from the growth facility and inserts a drawer of new chambers. All twelve of the drawers can be replaced in this fashion. The optical disks can also be removed this way. The old drawers are stored for the trip back to earth. Once inside the growth facility, a chamber is removed by the robot and placed in one of 144 active sites at a time previously picked by a technician. Growth begins when the chamber is inserted into an active site. Then, the sensing system starts to determine the size of the protein crystal. All during the crystal's growth, the customer can view the crystal and read all of the crystal's data, such as growth rate and crystal size. When the sensing system determines that the crystal has reached the predetermined size, the robot is

  9. Crystal Growth Using MEPHISTO

    NASA Technical Reports Server (NTRS)

    deGroh, Henry C., III

    1999-01-01

    The shuttle flight experiment "In Situ Monitoring of Crystal Growth Using MEPHISTO" was accomplished during STS-87 as part of the fourth flight of the United States Microgravity Payload (USMP-4), which was flown from November 19 to December 5, 1997. The data returned from that flight are just now beginning to yield quantitative results. This project is an international collaboration: the furnace system known as MEPHISTO was built in France by CNES (French National Space Agency) and CEA (French Atomic Energy Commission); the principal investigator, Prof. Reza Abbaschian, is from the University of Florida at Gainesville; and numerical and analytical modeling support includes collaborators from the University of New South Wales, Australia, the University of Wisconsin at Milwaukee, the National Institute of Standards and Technology, and the NASA Lewis Research Center. MEPHISTO is a French acronym that translates into English as Materials for the Study of Interesting Phenomena of Solidification on Earth and in Orbit. Since this was the fourth flight of the MEPHISTO furnace, the experiment is referred to as MEPHISTO-4. MEPHISTO-4 was a directional solidification experiment that studied the liquid-to-solid transformation of bismuth alloyed with tin. Directional solidification is a freezing technique common to the processing of the electronic materials used in integrated circuits and detectors, such as silicon and germanium. When liquids are frozen on Earth, they must be cooled. The cooling causes stirring because of density variations in the liquid. This stirring, known as natural convection, influences the quality of the resulting solid. During freezing, regions of high and low concentrations of tin are created. This introduces another important phenomenon: diffusion, or the movement by molecular action of matter from regions of high concentration to regions of lower concentration. In MEPHISTO-4, it is tin that diffuses from the high-concentration region in front of the

  10. The growth hormone receptor.

    PubMed

    Waters, Michael J

    2016-06-01

    Once thought to be present only in liver, muscle and adipose tissue, the GH receptor is now known to be ubiquitously distributed, in accord with the many pleiotropic actions of GH. These include the regulation of metabolism, postnatal growth, cognition, immune, cardiac and renal systems and gut function. GH exerts these actions primarily through alterations in gene expression, initiated by activation of its membrane receptor and the resultant activation of the associated JAK2 (Janus kinase 2) and Src family kinases. Receptor activation involves hormone initiated movements within a receptor homodimer, rather than simple receptor dimerization. We have shown that binding of the hormone realigns the orientation of the two receptors both by relative rotation and by closer apposition just above the cell membrane. This is a consequence of the asymmetric placement of the binding sites on the hormone. Binding results in a conversion of parallel receptor transmembrane domains into a rotated crossover orientation, which produces separation of the lower part of the transmembrane helices. Because the JAK2 is bound to the Box1 motif proximal to the inner membrane, receptor activation results in separation of the two associated JAK2s, and in particular the removal of the inhibitory pseudokinase domain from the kinase domain of the other JAK2 (and vice versa). This brings the two kinase domains into position for trans-activation and initiates tyrosine phosphorylation of the receptor cytoplasmic domain and other substrates such as STAT5, the key transcription factor mediating most genomic actions of GH. There are a limited number of genomic actions initiated by the Src kinase family member which also associates with the upper cytoplasmic domain of the receptor, including important immune regulatory actions to dampen exuberant innate immune activation of cells involved in transplant rejection. These findings offer insights for developing specific receptor antagonists which may be

  11. Universal Description of Interactive Growth

    NASA Astrophysics Data System (ADS)

    Condat, Carlos; Barberis, Lucas

    2011-03-01

    Although the existence of organism-organism interactions during ontogenesis is well documented, ontogenetic growth models usually focus exclusively on the organism-environment interaction. We develop a new formalism to describe the interactive growth of two or more organisms in a given environment. Using a vector formulation of the Phenomenological Universalities concept, we are able to characterize the joint growth of two or more interacting organisms and assess the direct mutual influences between them, as well as the indirect influences that operate through environment modifications. The resulting equations describe synergetic, antagonistic, and cooperative growth, and can be applied to biological and ecological problems. As an example, we examine the growth dynamics in a mixed-species plantation. This work was supported by ANPCyT and CONICET (Argentina).

  12. Growth declines in red spruce

    SciTech Connect

    McLaughlin, S.B. ); Adams, H.S. )

    1987-10-01

    In this letter, the authors take issue with Zedaker, Hyink, and Smith who have indicated that observed red spruce growth declines can be expected based on growth trends for even-aged stands of red spruce as documented in Meyer (1929). Recently, an examination was made of stand stocking levels at 750 sites where red spruce were cored and neither the rate of growth decline nor the extent of mortality were found to be related to stand stocking levels or previous disturbance history. The authors conclude that the Meyer data do not represent an appropriate model for stand dynamics of old-growth, high-elevation stands and no not adequately explain the growth declines observed at many of those sites.

  13. Pattern formation with proportionate growth

    NASA Astrophysics Data System (ADS)

    Dhar, Deepak

    It is a common observation that as baby animals grow, different body parts grow approximately at same rate. This property, called proportionate growth is remarkable in that it is not encountered easily outside biology. The models of growth that have been studied in Physics so far, e.g diffusion -limited aggregation, surface deposition, growth of crystals from melt etc. involve only growth at the surface, with the inner structure remaining frozen. Interestingly, patterns formed in growing sandpiles provide a very wide variety of patterns that show proportionate growth. One finds patterns with different features, with sharply defined boundaries. In particular, even with very simple rules, one can produce patterns that show striking resemblance to those seen in nature. We can characterize the asymptotic pattern exactly in some special cases. I will discuss in particular the patterns grown on noisy backgrounds. Supported by J. C. Bose fellowship from DST (India).

  14. Crystal growth inside an octant.

    PubMed

    Olejarz, Jason; Krapivsky, P L

    2013-08-01

    We study crystal growth inside an infinite octant on a cubic lattice. The growth proceeds through the deposition of elementary cubes into inner corners. After rescaling by the characteristic size, the interface becomes progressively more deterministic in the long-time limit. Utilizing known results for the crystal growth inside a two-dimensional corner, we propose a hyperbolic partial differential equation for the evolution of the limiting shape. This equation is interpreted as a Hamilton-Jacobi equation, which helps in finding an analytical solution. Simulations of the growth process are in excellent agreement with analytical predictions. We then study the evolution of the subleading correction to the volume of the crystal, the asymptotic growth of the variance of the volume of the crystal, and the total number of inner and outer corners. We also show how to generalize the results to arbitrary spatial dimension. PMID:24032777

  15. Web-dendritic ribbon growth

    NASA Technical Reports Server (NTRS)

    Hilborn, R. B., Jr.; Faust, J. W., Jr.

    1976-01-01

    A web furnace was constructed for pulling dendritic-web samples. The effect of changes in the furnace thermal geometry on the growth of dendritic-web was studied. Several attempts were made to grow primitive dendrites for use as the dendritic seed crystals for web growth and to determine the optimum twin spacing in the dendritic seed crystal for web growth. Mathematical models and computer programs were used to determine the thermal geometries in the susceptor, crucible melt, meniscus, and web. Several geometries were determined for particular furnace geometries and growth conditions. The information obtained was used in conjunction with results from the experimental growth investigations in order to achieve proper conditions for sustained pulling of two dendrite web ribbons. In addition, the facilities for obtaining the following data were constructed: twin spacing, dislocation density, web geometry, resistivity, majority charge carrier type, and minority carrier lifetime.

  16. Growth disturbances without growth arrest after ACL reconstruction in children.

    PubMed

    Chotel, Franck; Henry, Julien; Seil, Romain; Chouteau, Julien; Moyen, Bernard; Bérard, Jérôme

    2010-11-01

    Growth arrest is a major concern after ACL reconstruction in children. It usually occurs in patients near to closure of the growth plates. Growth disturbances without growth arrest are also possible and more vicious; the authors analyse the mechanism of two patients with growth disturbance due to overgrowth following ACL reconstruction. One was a symmetrical overgrowth process with 15 mm limb length discrepancy treated with percutaneous epiphysiodesis. Full correction at the time of skeletal maturity was achieved. The second patient developed an asymmetrical overgrowth with progressive tibial valgus deformity. This mechanism was similar to a posttraumatic tibial valgus deformity. After nonoperative treatment, a spontaneous correction of the deformity was noticed. Both children were young (7 and 10 years old) at the time of ACL reconstruction with an autologous iliotibial band graft. The clinical relevance of overgrowth disturbance is usually limited when compared to growth arrest but could require a second surgical procedure as reported in this study. Parents must be informed that even in experienced hands, and despite the use of a physeal sparing technique, this specific risk of growth disturbance is still present. PMID:20182870

  17. Growth Modes and Energetics of 101 Face Lysozyme Crystal Growth

    NASA Technical Reports Server (NTRS)

    Gorti, Sridhar; Forsythe, Elizabeth L.; Pusey, L.

    2004-01-01

    From analyses of lysozyme 101 face growth rate data using a 2D nucleation model for layer-by-layer growth, we find the effective barrier for crystal growth to be gamma = 1.0 +/- 0.2 x 10(exp -13) erg/molecule. The magnitude of the effective barrier is 2.4 +/- 0.5 k(sub beta)T, at 22 C. We also find that beyond a critical solution supersaturation, sigma(sub c), crystal growth rates are more accurately described by a kinetic roughening hypothesis. Beyond sigma(sub c), crystals grow by the continuous addition of molecules anywhere on the crystal surface rather than layer-by-layer. The magnitude of the critical supersaturation (sigma(sub c), = 1.7 +/- 0.2) for a crossover from a layer-by-layer to continuous growth is found to be statistically independent of the solution conditions that vary with buffer pH, temperature or precipitant concentration. Using the experimentally determined values for gamma and sigma(sub c), we find the crystal growth unit to be comprised of 7 +/- 3 molecules. The energy barrier, E(sub c), for the continuous addition of the growth Units is 6.2 +/- 0.3 x 10(exp -13) erg/molecule or 15 +/1 1 k(sub beta)T at 22C.

  18. Subcritical crack growth in marble

    NASA Astrophysics Data System (ADS)

    Nara, Yoshitaka; Nishida, Yuki; Toshinori, Ii; Harui, Tomoki; Tanaka, Mayu; Kashiwaya, Koki

    2016-04-01

    It is essential to study time-dependent deformation and fracturing in various rock materials to prevent natural hazards related to the failure of a rock mass. In addition, information of time-dependent fracturing is essential to ensure the long-term stability of a rock mass surrounding various structures. Subcritical crack growth is one of the main causes of time-dependent fracturing in rock. It is known that subcritical crack growth is influenced by not only stress but also surrounding environment. Studies of subcritical crack growth have been widely conducted for silicate rocks such as igneous rocks and sandstones. By contrast, information of subcritical crack growth in carbonate rocks is not enough. Specifically, influence of surrounding environment on subcritical crack growth in carbonate rock should be clarified to ensure the long-term stability of a rock mass. In this study, subcritical crack growth in marble was investigated. Especially, the influence of the temperature, relative humidity and water on subcritical crack growth in marble is investigated. As rock samples, marbles obtained in Skopje-City in Macedonia and Carrara-City in Italy were used. To measure subcritical crack growth, we used the load relaxation method of the double-torsion (DT) test. All measurements by DT test were conducted under controlled temperature and relative humidity. For both marbles, it was shown that the crack velocity in marble in air increased with increasing relative humidity at a constant temperature. Additionally, the crack velocity in water was much higher than that in air. It was also found that the crack velocity increased with increasing temperature. It is considered that temperature and water have significant influences on subcritical crack growth in marble. For Carrara marble in air, it was recognized that the value of subcritical crack growth index became low when the crack velocity was higher than 10-4 m/s. This is similar to Region II of subcritical crack growth

  19. The relative value of growth.

    PubMed

    Mass, Nathaniel J

    2005-04-01

    Most executives would say that adding a point of growth and gaining a point of operating-profit margin contribute about equally to shareholder value. Margin improvements hit the bottom line immediately, while growth compounds value over time. But the reality is that the two are rarely equivalent. Growth often is far more valuable than managers think. For some companies, convincing the market that they can grow by just one additional percentage point can be worth six, seven, or even ten points of margin improvement. This article presents a new strategic metric, called the relative value of growth (RVG), which gives managers a clear picture of how growth projects and margin improvement initiatives affect shareholder value. Using basic balance sheet and income sheet data, managers can determine their companies' RVGs, as well as those of their competitors. Calculating RVGs gives managers insights into which corporate strategies are working to deliver value and whether their companies are pulling the most powerful value-creation levers. The author examines a number of well-known companies and explains what their RVG numbers say about their strategies. He reviews the unspoken assumption that growth and profits are incompatible over the long term and shows that a fair number of companies are effective at delivering both. Finally, he explains how managers can use the RVG framework to help them define strategies that balance growth and profitability at both the corporate and business unit levels. PMID:15807043

  20. Sociological explanations of economic growth.

    PubMed

    Marsh, R M

    1988-01-01

    Even if questions of how resources are distributed within and between societies are the main concern, it is necessary to continue to grapple with the issue of the causes of economic growth since economic growth and level of development continue to be among the most important causes of inequality, poverty, unemployment, and the quality of life. This paper's dependent variable is the economic growth rate of 55 less developed countries (LDCs) over 2 time periods. 1970-78 and 1965-84. The causal model consists of control variables--level of development and domestic investment in 1965--and a variety of independent variables drawn from major sociological theories of economic growth published during the last 3 decades. Multiple regression analysis shows that, net of the effects of the 2 control variables, the variables which have the strongest effect on economic growth are: 1) direct foreign investment, which has a negative effect, 2) the proportion of the population in military service, and 3) the primary school enrollment ratio, both of which have positive effects on economic growth. On the other hand, variables drawn from some theories receive no empirical support. The mass media of communications, ethnolinguistic heterogeneity, democracy and human rights, income inequality, and state-centric theory's key variable, state strength, all fail to show any significant impact on economic growth rates when the control variables and the significant independent variables are held constant. The theoretical implications of these findings are discussed. PMID:12282217

  1. Scaling Behavior of Firm Growth

    NASA Astrophysics Data System (ADS)

    Stanley, Michael H. R.; Nunes Amaral, Luis A.; Buldyrev, Sergey V.; Havlin, Shlomo; Leschhorn, Heiko; Maass, Philipp; Salinger, Michael A.; Stanley, H. Eugene

    1996-03-01

    The theory of the firm is of considerable interest in economics. The standard microeconomic theory of the firm is largely a static model and has thus proved unsatisfactory for addressing inherently dynamic issues such as the growth of economies. In recent years, many have attempted to develop richer models that provide a more accurate representation of firm dynamics due to learning, innovative effort, and the development of organizational infrastructure. The validity of these new, inherently dynamic theories depends on their consistency with the statistical properties of firm growth, e.g. the relationship between growth rates and firm size. Using the Compustat database over the time period 1975-1991, we find: (i) the distribution of annual growth rates for firms with approximately the same sales displays an exponential form with the logarithm of growth rate, and (ii) the fluctuations in the growth rates --- measured by the width of this distribution --- scale as a power law with the firm sales. We place these findings of scaling behavior in the context of conventional economics by considering firm growth dynamics with temporal correlations and also, by considering a hierarchical organization of the departments of a firm.

  2. Transport and Growth Kinetics in Microgravity Protein Crystal Growth

    NASA Technical Reports Server (NTRS)

    Otalora, F.; Garcia-Ruiz, J. M.; Carotenuto, L.; Castagnolo, D.; Novella, M. L.; Chernov, A. A.

    2002-01-01

    The dynamic coupling between mass transport and incorporation of growth units into the surface of a crystal growing from solution in microgravity is used to derive quantitative information on the crystal growth kinetics. To this end, new procedures for experiment preparation, interferometric data processing and model fitting have been developed. The use of experimental data from the bulk diffusive maw transport together with a model for steady state stagnant crystal growth allows the detailed quantitative understanding of the kinetics of both the concentration depletion zone around the crystal and the growth of the crystal interface. The protein crystal used in the experiment is shown to be growing in the mixed kinetic regime (0.2 x 10(exp -6) centimeters per second less than beta R/D less than 0.9 x 10(exp -6) centimeters per second).

  3. Nanoparticle growth. Facet development during platinum nanocube growth.

    PubMed

    Liao, Hong-Gang; Zherebetskyy, Danylo; Xin, Huolin; Czarnik, Cory; Ercius, Peter; Elmlund, Hans; Pan, Ming; Wang, Lin-Wang; Zheng, Haimei

    2014-08-22

    An understanding of how facets of a nanocrystal develop is critical for controlling nanocrystal shape and designing novel functional materials. However, the atomic pathways of nanocrystal facet development are mostly unknown because of the lack of direct observation. We report the imaging of platinum nanocube growth in a liquid cell using transmission electron microscopy with high spatial and temporal resolution. The growth rates of all low index facets are similar until the {100} facets stop growth. The continuous growth of the rest facets leads to a nanocube. Our calculation shows that the much lower ligand mobility on the {100} facets is responsible for the arresting of {100} growing facets. These findings shed light on nanocrystal shape-control mechanisms and future design of nanomaterials. PMID:25146287

  4. Groove growth by surface subdiffusion

    NASA Astrophysics Data System (ADS)

    Abu Hamed, M.; Nepomnyashchy, A. A.

    2015-04-01

    The investigation of the grain-boundary groove growth by normal surface diffusion was first done by Mullins. However, the diffusion on a solid surface is often anomalous. Recently, the groove growth in the case of surface superdiffusion has been analyzed. In the present paper, the problem of the groove growth is solved in the case of the surface subdiffusion. An exact self-similar solution is obtained and represented in terms of the Fox H-function. Basic properties of the solution are described.

  5. Attached-growth biological reactor

    SciTech Connect

    O'Brien, D.J.; Heiland, W.K.

    1991-12-16

    An attached growth biological reactor for the growth and harvesting of filamentous fungi has been developed. The reactor contains a rigid cylinder which is partially submerged and rotated in a biological medium containing nutrients for fungal growth and which has been inoculated with a filamentous fungal medium. The filamentous fungi attaches itself to and grows upon the cylinder wherein it is removed by use of a doctoring blade. The reactor can be operated in a continuous mode by continuously supplying oxygen and nutrients to the reactor.

  6. The biophysics of neuronal growth

    NASA Astrophysics Data System (ADS)

    Franze, Kristian; Guck, Jochen

    2010-09-01

    For a long time, neuroscience has focused on biochemical, molecular biological and electrophysiological aspects of neuronal physiology and pathology. However, there is a growing body of evidence indicating the importance of physical stimuli for neuronal growth and development. In this review we briefly summarize the historical background of neurobiophysics and give an overview over the current understanding of neuronal growth from a physics perspective. We show how biophysics has so far contributed to a better understanding of neuronal growth and discuss current inconsistencies. Finally, we speculate how biophysics may contribute to the successful treatment of lesions to the central nervous system, which have been considered incurable until very recently.

  7. Dinosaurian growth patterns and rapid avian growth rates.

    PubMed

    Erickson, G M; Rogers, K C; Yerby, S A

    2001-07-26

    Did dinosaurs grow in a manner similar to extant reptiles, mammals or birds, or were they unique? Are rapid avian growth rates an innovation unique to birds, or were they inherited from dinosaurian precursors? We quantified growth rates for a group of dinosaurs spanning the phylogenetic and size diversity for the clade and used regression analysis to characterize the results. Here we show that dinosaurs exhibited sigmoidal growth curves similar to those of other vertebrates, but had unique growth rates with respect to body mass. All dinosaurs grew at accelerated rates relative to the primitive condition seen in extant reptiles. Small dinosaurs grew at moderately rapid rates, similar to those of marsupials, but large species attained rates comparable to those of eutherian mammals and precocial birds. Growth in giant sauropods was similar to that of whales of comparable size. Non-avian dinosaurs did not attain rates like those of altricial birds. Avian growth rates were attained in a stepwise fashion after birds diverged from theropod ancestors in the Jurassic period. PMID:11473315

  8. Au growth on semiconductor nanorods: photoinduced versus thermal growth mechanisms.

    PubMed

    Menagen, Gabi; Macdonald, Janet E; Shemesh, Yossi; Popov, Inna; Banin, Uri

    2009-12-01

    Gold growth on CdS nanorods and on seeded CdSe/CdS nanorods with and without illumination at different temperatures was studied. Two competing mechanisms were identified: thermal and light-induced growth. The thermal mechanism leads to growth of small gold particles at defects along the rod body and can be suppressed at lower temperatures. This control is attributed to a phase transition of the alkyl chains of the surface amine ligands to a static phase at lower temperatures, blocking the Au precursor's access to the nanorod surfaces. While a long-chain (C18) amine shows effective blocking at 293 K, a shorter chain (C12) amine shows the same result only at 273 K; however, in the case of a bulky trialkylamine, defect growth was observed even at 273 K. Light-induced growth leads to selective deposition of gold on one end of the rods. The tip was shown to grow on sulfur-rich facets of the nanorod, producing end-on and angled tip orientations. Growth under illumination with decreased temperature provides a highly selective synthesis of hybrid semiconductor nanorods with a single gold tip. Such anisotropic semiconductor-metal hybrids are of interest for self-assembly and photocatalysis and as building blocks in optoelectronic devices. PMID:19894717

  9. Growth of silicon sheets for photovoltaic applications

    SciTech Connect

    Surek, T.

    1980-12-01

    The status of silicon sheet development for photovoltaic applications is critically reviewed. Silicon sheet growth processes are classified according to their linear growth rates. The fast growth processes, which include edge-defined film-fed growth, silicon on ceramic, dendritic-web growth, and ribbon-to-ribbon growth, are comparatively ranked subject to criteria involving growth stability, sheet productivity, impurity effects, crystallinity, and solar cell results. The status of more rapid silicon ribbon growth techniques, such as horizontal ribbon growth and melt quenching, is also reviewed. The emphasis of the discussions is on examining the viability of these sheet materials as solar cell substrates for low-cost silicon photovoltaic systems.

  10. Differential effects of estrogen and medroxyprogesterone on basal and stress-induced growth hormone release, IGF-1 levels, and cellular immunity in postmenopausal women.

    PubMed

    Malarkey, W B; Burleson, M; Cacioppo, J T; Poehlmann, K; Glaser, R; Kiecolt-Glaser, J K

    1997-10-01

    We evaluated the influence of continual estrogen replacement therapy (ERT) as presently practiced by postmenopausal women with conjugated estrogens and medroxyprogesterone acetate (MPA) on the growth hormone/insulin-like growth factor-1 (GH/IGF-1) axis and cellular immunity. Thirty-nine postmenopausal women were evaluated (12 on no replacement, 14 on estrogen only, and 13 on estrogen and MPA). In the women receiving only conjugated estrogens, increased GH levels and decreased IGF-1 levels were found, which replicated previous research and probably reflected estrogen inhibition of hepatic IGF-1 production with a secondary increase in GH release because of reduced feedback inhibition. In women taking both MPA and estrogen, GH was increased and the previously observed estrogen induced decrease in IGF-1 levels was inhibited. In order to determine the influence of ERT on psycho-social stress-induced GH release, math (mental stress) and speech (social stress) challenges were utilized, and they produced significant increases in heart rate in all three groups. The heart rate following stress was significantly enhanced by estrogen replacement. These stressors also led to increased GH secretion in the women taking estrogen and MPA, but not in the other two groups. Gonadal steroids and GH can influence cellular immunity. We observed that ERT in both groups was associated with significantly enhanced lymphocyte responsiveness to the T-cell mitogens phytohemaglutinin (PHA) and Conconavalin A (Con A), and basal GH levels were correlated with the PHA response in the estrogen only group. ERT did not influence natural killer (NK) cell activity. We also found significant differences in the steady-state expression of latent Epstein-Barr virus (EBV) with increased antibody titers in the women in the estrogen only group and lower antibody titers in the MPA plus estrogen group. GH levels were correlated with EBV antibody titers in the estrogen plus MPA group. This study supports the