1,721,198 research outputs found
Lipid-like material as the source of the uncharacterized organic carbon in the ocean?
No full textThe composition and formation mechanisms of the uncharacterized fraction of oceanic particulate organic carbon (POC) are not well understood. We isolated biologically important compound classes and the acid-insoluble fraction, a proxy of the uncharacterized fraction, from sinking POC in the deep Northeast Pacific and measured carbon isotope ratios to constrain the source(s) of the uncharacterized fraction. Stable carbon and radiocarbon isotope signatures of the acid-insoluble fraction were similar to those of the lipid fraction, implying that the acid-insoluble fraction might be composed of selectively accumulated lipid-like macromolecules.X1155sciescopu
Impact of Type 2 Diabetes Mellitus and Antidiabetic Medications on Bone Metabolism
No full textPURPOSE OF REVIEW: This review focuses on the complex interactions between hyperglycemia and bone fragility and the effects of antidiabetic medications on bone metabolism.
RECENT FINDINGS: Type 2 diabetes (T2D) is associated with increased risk of bone fracture even in those with increased or normal bone mineral density (BMD). The pathophysiology of diabetic bone disease is not completely understood, but it is thought to be multifactorial and associated with complex cross talk among factors such as AGEs, IGF-1, enteric hormones, and pro-inflammatory cytokines. Treatment for T2D may have an impact on bone metabolism. Diabetic bone disease should be considered a serious complication of long-standing T2D
Genetic aspects of type 1 diabetes
Full text linkType 1 diabetes mellitus (T1DM) is characterized by autoimmune destruction of pancreatic beta-cells in genetically predisposed individuals, eventually resulting in severe insulin deficiency. It is the most common form of diabetes in children and adolescents. Genetic susceptibility plays a crucial role in development of T1DM. The human leukocyte antigen complex plays a key role in the pathogenesis of T1DM. Furthermore, genome-wide association studies and linkage analysis have recently made a significant contribution to current knowledge relative to the impact of genetics on T1DM development and progression. This review focuses on current knowledge of genetics as a pathogenesis for T1DM. It also discusses mechanisms by which genes influence the risk of developing T1DM as well as the clinical and research applications of genetic risk scores in T1DM
Incorporation of aged dissolved organic carbon (DOC) by oceanic particulate organic carbon (POC): An experimental approach using natural carbon isotopes
No full textIncorporation of 14 C-depleted (old) dissolved organic carbon (DOC) on/into particulate organic carbon (POC) has been suggested as a possible mechanism to explain the low Delta C-14-POC values observed in the deep ocean [Druffel, E.R.M., Williams, P.M., 1990. Identification of a deep marine source of particulate organic carbon using bomb C-14. Nature, 347, 172-174.]. A shipboard incubation experiment was performed in the Sargasso Sea to test this hypothesis. Finely ground dried plankton was incubated in seawater samples from the deep Sargasso Sea, both with and without a biological poison (HgCl2). Changes ill parameters such as biochemical composition and carbon isotopic signatures of bulk POC and its organic compound classes were examined to study the roles of sorptive processes and biotic activity on POC character. Following a 13-day incubation, the relative abundance of the acid-insoluble organic fraction increased. Abundances of extractable lipids and total hydrolyzable amino acids decreased for both treatments, but by a greater extent in the non-poisoned treatment. The Delta C-14 values of POC recovered from the non-poisoned treatment were significantly lower than the value of the unaltered plankton material used for the incubation, indicating incorporation of C-14-depleted carbon, most likely DOC. The old carbon was present only in the lipid and acid-insoluble fractions. These results are consistent with previous findings of old carbon dominating the same organic fractions of sinking POC from the deep Northeast Pacific [Hwang, J., Druffel, E.R.M., 2003. Lipid-like material as the Source of the uncharacterized organic carbon in the ocean? Science, 299, 881-884.]. However, the Delta C-14 values of POC recovered from the poisoned treatment did not change as much as those from the non-poisoned treatment suggesting that biological processes were involved in the incorporation of DOC on/into POC. (c) 2005 Elsevier B.V. All rights reserved.X1122sciescopu
Effects of bonding temperature on the properties and reliabilities of anisotropic conductive films (ACFs) for flip chip on organic substrate application
No full textThe effects of bonding temperatures on the composite properties and reliability performances of anisotropic conductive films (ACFs) for flip chip on organic substrates assemblies were studied. As the bonding temperature decreased, the composite properties of ACF, such as water absorption, glass transition temperature (T-g), elastic modulus (E') and coefficient of thermal expansion (a), were improved. These results were due to the difference in network structures of cured ACFs which were fully cured at different temperatures. From small angle X-ray scattering (SAXS) test result, ACFs cured at lower temperature, had denser network structures. The reliability performances of flip chip on organic substrate assemblies using ACFs were also investigated as a function of bonding temperatures. The results in thermal cycling test (-55 degrees C/+1 50 degrees C, 1000 cycles) and PCT (121 degrees C, 100% RH, 96 h) showed that the lower bonding temperature resulted in better reliability of the flip chip interconnects using ACFs. Therefore, the composite properties of cured ACF and reliability of flip chip on organic substrate assemblies using ACFs were strongly affected by the bonding temperature. (C) 2007 Elsevier Ltd. All rights reserved
Growth Prediction Model for Prepubertal Children With Idiopathic Growth Hormone Deficiency: An Analysis of LG Growth Study Data
No full textBACKGROUND: Growth hormone (GH) treatment is effective in restoring normal growth in children with GH deficiency (GHD). However, individual responses to GH treatment vary, necessitating predictive models to estimate growth outcomes. This study aimed to develop and validate a predictive model for GH treatment response during the first 2 years in patients with idiopathic GHD using the LG growth study (LGS) database. METHODS: This observational study included 669 prepubertal patients with idiopathic GHD from the LGS registry who received GH treatment for at least 2 years. Clinical and laboratory data were collected at baseline and every 6 months thereafter. Stepwise multivariate regression analysis was performed to develop prediction models for the treatment period. RESULTS: The mean age of patients with GDH was 6.0 +/- 1.8 years. Height standard deviation score (SDS) significantly increased from -2.50 +/- 0.71 to -1.66 +/- 0.71 in the first year and -1.35 +/- 0.71 in the second year. The first-year growth velocity was 9.06 +/- 1.51 cm, decreasing to 7.42 +/- 1.37 cm in the second year. The prediction models incorporated variables such as age, birth weight, bone age, initial height SDS, body mass index SDS, mid-parental height, GH dose and first year of height after GH treatment, explaining 76.9% and 84.1% of the variability in height SDS changes in the first and second years, respectively. CONCLUSIONS: GH treatment significantly improves height outcomes in prepubertal children with GHD. The developed predictive models demonstrated accuracy, facilitating personalized GH therapy. Future research should focus on refining these models and exploring the long-term effects of GH treatment in pubertal patients. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01604395
Changes in body mass index in boys with central precocious puberty over 2 years of gonadotropin-releasing hormone agonist therapy
Full text linkPURPOSE: Gonadotropin-releasing hormone agonist (GnRHa) is a safe and effective therapy used to treat central precocious puberty (CPP). Although most studies have reported no significant difference in body mass index (BMI) in girls during and after GnRHa therapy, few studies have investigated changes in BMI in boys with CPP. This study evaluated the effects of GnRHa therapy on BMI in boys with CPP.
METHODS: This study included 75 boys with CPP at Ajou University Hospital between January 1, 2007 and December 31, 2016, who treated with leuprorelin acetate or triptorelin acetate every 4 weeks for at least 2 years. The subjects were divided into 3 groups according to BMI: normal weight, overweight, and obese. We analyzed the BMI standard deviation score (SDS) in each group before therapy and after 1 year and 2 years of therapy.
RESULTS: Of the 75 boys, 37 were in the normal weight group, 21 were in the overweight group, and 17 were in the obese group. Magnetic resonance imaging that was performed before treatment showed abnormal findings in 9 boys. The mean BMI SDS for all participants at initiation was 1.0+/-0.8, and that in the normal weight, overweight, and obese groups was 0.3+/-0.4, 1.3+/-0.1, and 1.9+/-0.3, respectively. There were no significant differences in BMI SDS in any group after 1 or 2 years of treatment.
CONCLUSION: The BMI SDS in boys with CPP did not significantly change over 2 years of GnRHa therapy
Association study of DLK1 in girls with idiopathic central precocious puberty
No full textObjective Mutations in the delta-like 1 homolog (DLK1) gene have recently been reported in patients with idiopathic central precocious puberty (CPP). We aimed to investigate DLK1 mutations or polymorphisms in girls with CPP. Methods A total of 100 girls diagnosed with idiopathic CPP were enrolled. DLK1 coding regions were sequenced in girls with idiopathic CPP and healthy girls (controls). The relationship between identified sequence variations and CPP was evaluated via comparison of allele frequencies between patients with CPP and normal healthy controls. Results We identified five polymorphisms in DLK1. There was no significant difference with regard to allele frequency between patients with CPP and controls. Polymorphism c.549C>T (p.G183G) in DLK1 gene was identified in only one patient with CPP. In silico analysis with human splicing finder suggested that the variant (c.549C>T) leads to splicing defect. Conclusions The sequencing of DLK1 gene has uncovered only one potentially meaningful variant. However, our results demonstrate that DLK1 mutations are a relatively rare cause of idiopathic CPP
Effects of epoxy functionality on the properties and reliability of the anisotropic conductive films for flip chips on organic substrates
No full textThe effects of the functionality of an epoxy monomer on the composite properties and reliability of anisotropic conductive films (ACFs) in a flip-chip package were investigated. Three epoxy monomers with different functionalities (f = 2-4) were considered. The ACFs prepared using epoxy monomers with higher functionality resulted in lower molecular weight between crosslinks (M-c). As the M-c decreased, the elastic modulus (E') and coefficient of thermal expansion (CTE) were improved. These results were highly consistent with the rubber elasticity theory. The reliability performance of the flip chip on organic substrate assemblies using ACFs were also investigated as a function of epoxy functionality. The ACFs prepared by using higher functional epoxy monomers showed improved reliability performance.Financial support from Center for Electronic
Packaging Materials (CEPM) of the Korea Science
and Engineering Foundation (KOSEF) is gratefully
acknowledged
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