Adsorption of metal ions on nitrogen surface functional groups in activated carbons

A commercially available coconut-shell-derived active carbon was oxidized with nitric acid, and both the original and oxidized active carbons were treated with ammonia at 1073 K to incorporate nitrogen functional groups into the carbon. An active carbon with very high nitrogen content (similar to9.4 wt % daf) was also prepared from a nitrogen-rich precursor, polyacrylonitrile (PAN). These nitrogen-rich carbons had points of zero charge (pH(pzc)) similar to H-type active carbons. X-ray absorption near-edge structure (XANES) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and temperature-programmed desorption (TPD) were used to characterize the nitrogen functional groups in the carbons. The nitrogen functional groups present on the carbon surface were pyridinic, pyrrolic (or indolic), and pyridonic structures. The adsorption of transition metal cations Cd2+, Ni2+, and Cu2+ from aqueous solution on the suite of active carbons showed that adsorption was markedly higher for carbons with nitrogen functional groups present on the surface than for carbons with similar pH(pzc) values. In contrast, the adsorption characteristics of Ca2+ from aqueous solution were similar for all the carbons studied. Flow microcalorimetry (FMC) studies showed that the enthalpies of adsorption of Cd2+(aq) on the active carbons with high nitrogen contents were much higher than for nitric acid oxidized carbons studied previously, which also had enhanced adsorption characteristics for metal ion species. The enthalpies of adsorption of Cu2+ were similar to those obtained for Cd2+ for specific active carbons. The nitrogen functional groups in the carbons act as surface coordination sites for the adsorption of transition metal ions from aqueous solution. The adsorption characteristics of these carbons are compared with those of oxidized carbons.

A computational study of the mechanism of CO oxidation by a ceria supported surface rhodium oxide layer

A mechanism of CO oxidation by a thin surface oxide of Rh supported on ceria is proposed: CO is oxidized by the Rh-oxide film, which is subsequently reoxidized by a ceria surface O atom. The proposed mechanism is supported by in situ Raman spectroscopic investigations.

Mutation screening and genotype:phenotype correlation in familial hypercholesterolaemia

The aim of this study was to develop a mutation screening protocol for familial hypercholesterolaemia (FH) patients and to assess genotype/phenotype effects in terms of pre-treatment lipid profiles and presentation of tendon xanthomata (TX). A total of 158 families with clinical definitions of possible (120) or definite (38) FH were studied using a tiered screening protocol. Mutations were identified in 52 families, 44 families showing 23 different LDLR gene defects and eight families showing the common Apo B100 gene defect R3500Q. LDLR defects were detected in various regions of the gene with 56% in the LDL binding domain (exons 2-6) and 37% in the EGF precursor homology domain (exons 7-14). The most common mutations were D461N(7), C210X(5), 932delA(5), and C163Y(4). Frameshift mutations accounted for 20% with nonsense 13%, mis-sense 35%, splice 3%, Apo B 13% and 2% large deletion, 13% of clinically definite FH remained undefined. In conclusion, DNA based diagnosis is possible in 79% (30/38) of clinically definite FH families and of the 120 possible FH families at the start of the screening program, 18% (22/120) now have defined mutations. Overall 60 families from the original 158 meet the clinical and/or genetic criteria for definite FH. Tendon xanthomata were present in only 58% (30/52) of genetically defined FH families, thus limiting its use as a strict diagnostic criteria. Families with low density lipoprotein receptor (LDLR) defects present with higher total and LDL cholesterol levels and a higher incidence of TX than do those with the common Apo B variant, and frameshift mutations appear to have the most severe presentation. Copyright (C) 1999 Elsevier Science Ireland Ltd.

Complement expression in retinal pigment epithelial cells is modulated by activated macrophages

Complement activation is involved in a variety of retinal diseases. We have shown previously that a number of complement components and regulators can be produced locally in the eye, and that retinal pigment epithelial (RPE) cells are the major source of complement expression at the retina-choroidal interface. The expression of complement components by RPE cells is regulated by inflammatory cytokines. Under aging or inflammatory conditions, microglia and macrophages accumulate in the subretinal space, where they are in close contact with RPE cells. In this study, we investigated the effect of activated macrophages on complement expression by RPE cells. Mouse RPE cells were treated with the supernatants from un-activated bone marrow-derived macrophages (BM-DMs), the classically activated BM-DMs (M1) and different types of the alternatively activated BM-DMs (M2a by IL-4, M2b by immune complex and lipopolysaccharide (LPS), M2c by IL-10). The expression of inflammatory cytokines and complement genes by RPE cells were determined by real-time RT-PCR. The protein expression of CFB, C3, C1INH, and C1r was examined by Western blot. Our results show that un-stimulated RPE cells express a variety of complement-related genes, and that the expression levels of complement regulators, including C1r, factor H (CFH), DAF1, CD59, C1INH, Crry, and C4BP genes are significantly higher than those of complement component genes (C2, C4, CFB, C3, and C5). Macrophage supernatants increased inflammatory cytokine (IL-1ß, IL-6, iNOS), chemokine (CCL2) and complement expression in RPE cells. The supernatants from M0, M2a and M2c macrophages mildly up-regulated (2~3.5-fold) CFB, CFH and C3 gene expression in RPE cells, whereas the supernatants from M1 and M2b macrophages massively increased (10~30-fold) CFB and C3 gene expression in RPE cells. The expression of other genes, including C1r, C2, C4, CFH, Masp1, C1INH, and C4BP in RPE cells was also increased by the supernatants of M1 and M2b macrophages; however, the increment levels were significantly lower than CFB and C3 genes. M1 and M2b macrophage supernatants enhanced CFB (Bb fragment) protein expression and C3 secretion by RPE cells. M1 macrophages may affect complement expression in RPE cells through the STAT1 pathway. Our results suggest that under inflammatory conditions, activated macrophages could promote the alternative pathway of complement activation in the retina via induction of RPE cell CFB and C3 expression.

The effect of photo-oxidation on the sticking and reactivity of Ag on amorphous GeS2

Photo-oxidation of amorphous GeS2 films illuminated by band-gap radiation drastically alters the growth mode and reactivity of subsequently deposited Ag. In the former case (monolayer/simultaneous multilayer growth) the Ag reacts with both Ge and S sites. In the latter case (Stranski-Krastanov growth) Ge sites are selectively oxidized and film growth proceeds by Ag nucleation at the unoxidized S sites. The behaviour is very different from that reported earlier for Zn deposition on GeS2, where photo-oxidation results in very large changes in metal sticking probability. XPS, XAES and EXAFS data provide the basis for understanding both this phenomenon and the very different photodiffusion behaviour of Zn and Ag in GeS2.

Application of citrate-stabilized gold-coated ferric oxide composite nanoparticles for biological separations

Gold-coated magnetic nanoparticles were synthesized with size ranging from 15 to 40 nm using sodium citrates as the reducing agent. Oxidized magnetites (Fe3O4) fabricated by co-precipitation of Fe2+ and Fe3+ in strong alkaline solution were used as magnetic cores. The structures of gold (Au) shell and magnetic core (Au–Fe) were studied by transmission electron microscopy (TEM) image and energy dispersive spectroscopy (EDS) spectrum. Results from high-resolution X-ray diffraction (HR XRD) show that the Au–Fe oxide nanoparticles have a face-centered cubic shape with the crystalline faces of {1 1 1}. The Au-coated magnetic nanoparticles exhibited a surface plasmon resonance peak at 528 nm. The nanoparticles are well dispersed in distilled water. A 3000 G permanent magnet was successfully used for the separation of the functionalized nanoparticles. Magnetic properties of the nanoparticles were determined by magnetic force microscope (MFM) in nanometric resolution and vibrating sample magnetometer (VSM). Magnetic separation of biological molecules using Au-coated magnetic oxide composite nanoparticles was examined after attachment of protein immunoglobulin G (IgG) through electrostatic interactions. Using this method, separation was achieved with a maximum yield of 35% at an IgG concentration of 400 ng/ml.

Stochastic particle acceleration in the lobes of giant radio galaxies

We investigate the acceleration of particles by Alfven waves via the second-order Fermi process in the lobes of giant radio galaxies. Such sites are candidates for the accelerators of ultra-high-energy cosmic rays (UHECR). We focus on the nearby Fanaroff-Riley type I radio galaxy Centaurus A. This is motivated by the coincidence of its position with the arrival direction of several of the highest energy Auger events. The conditions necessary for consistency with the acceleration time-scales predicted by quasi-linear theory are reviewed. Test particle calculations are performed in fields which guarantee electric fields with no component parallel to the local magnetic field. The results of quasi-linear theory are, to an order of magnitude, found to be accurate at low turbulence levels for non-relativistic Alfven waves and at both low and high turbulence levels in the mildly relativistic case. We conclude that for pure stochastic acceleration via Alfven waves to be plausible as the generator of UHECR in Cen A, the baryon number density would need to be several orders of magnitude below currently held upper limits.

Plasma Lipoproteins and Preeclampsia in Women with Type 1 Diabetes: A Prospective Study

Context: In nondiabetic pregnancy, cross-sectional studies have shown associations between maternal dyslipidemia and preeclampsia (PE). In type 1 diabetes mellitus (T1DM), the prevalence of PE is increased 4-fold, but prospective associations with plasma lipoproteins are unknown.

Objectives: The aim of this study was to define lipoprotein-related markers and potential mechanisms for PE in T1DM.

Design and Settings: We conducted a multicenter prospective study in T1DM pregnancy.

Patients: We studied 118 T1DM women (26 developed PE, 92 remained normotensive). Subjects were studied at three visits before PE onset [12.2 1.9, 21.6 1.5, and 31.5 1.7 wk gestation (means SD)] and at term (37.6 2.0 wk). Nondiabetic normotensive pregnant women (n 21) were included for reference.

Main Outcome Measures: Conventional lipid profiles, lipoprotein subclasses [defined by size (nuclear magnetic resonance) and by apolipoprotein content], serum apolipoproteins (ApoAI, ApoB, and ApoCIII), and lipolysis (ApoCIII ratio) were measured in T1DM women with and without subsequent PE.

Results: In women with vs. without subsequent PE, at the first and/or second study visits: lowdensity lipoprotein (LDL)-cholesterol, particle concentrations of total LDL and large (but not small) LDL, serum ApoB, and ApoB:ApoAI ratio were all increased (P 0.05); peripheral lipoprotein lipolysis was decreased (P0.01). These early differences remained significant in covariate analysis (glycated hemoglobin, actual prandial status, gravidity, body mass index, and diabetes duration) but were not present at the third study visit. High-density lipoprotein and very low-density lipoprotein subclasses did not differ between groups before PE onset.

Conclusions: Early in pregnancy, increased cholesterol-rich lipoproteins and an index suggesting decreased peripheral lipolysis were associated with subsequent PE in T1DM women. Background maternal lipoprotein characteristics, perhaps masked by effects of late pregnancy, may influence PE risk.

The impact of sperm DNA damage in assisted conception and beyond: recent advances in diagnosis and treatment

Abstract Sperm DNA damage is a useful biomarker for male infertility diagnosis and prediction of assisted reproduction outcomes.
It is associated with reduced fertilization rates, embryo quality and pregnancy rates, and higher rates of spontaneous miscarriage
and childhood diseases. This review provides a synopsis of the most recent studies from each of the authors, all of whom have major
track records in the field of sperm DNA damage in the clinical setting. It explores current laboratory tests and the accumulating body
of knowledge concerning the relationship between sperm DNA damage and clinical outcomes. The paper proceeds to discuss the
strengths, weaknesses and clinical applicability of current sperm DNA tests. Next, the biological significance of DNA damage in
the male germ line is considered. Finally, as sperm DNA damage is often the result of oxidative stress in the male reproductive tract,
the potential contribution of antioxidant therapy in the clinical management of this condition is discussed. DNA damage in human spermatozoa is an important attribute of semen quality. It should be part of the clinical work up and properly controlled trials
addressing the effectiveness of antioxidant therapy should be undertaken as a matter of urgency.

Treatment approaches for diabetes and dyslipidemia

Dyslipidemia is an important risk factor for cardiovascular complications in persons with diabetes. Low-density lipoprotein-cholesterol (LDL-C) is the 'cornerstone' for assessment of lipoprotein-associated risk. However, LDL-C levels do not reflect the classic 'diabetic dyslipidemia' of hypertriglyceridemia and low high-density lipoprotein-cholesterol (HDL-C). Measurements of plasma apolipoprotein B100 concentrations and non-HDL-C may improve the definition of dyslipidemia. Statins, nicotinic acid and fibrates have roles in treating dyslipidemia in diabetes. Residual risk (i.e. risk that persists after correction of 'conventional' plasma lipoprotein abnormalities) is a new concept in the role of dyslipidemia in the pathogenesis of diabetic vascular complications. For example, regardless of plasma levels, lipoprotein extravasation through a leaking retinal blood barrier and subsequent modification may be crucial in the development of diabetic retinopathy. The current approach to the management of dyslipidemia in diabetes is briefly summarized, followed by a discussion of new concepts of residual risk and emerging lipoprotein-related mechanisms for vascular disease in diabetes.

Long-term renal outcomes of patients with type 1 diabetes mellitus and microalbuminuria:an analysis of the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications cohort

Microalbuminuria is a common diagnosis in the clinical care of patients with type 1 diabetes mellitus. Long-term outcomes after the development of microalbuminuria are variable.

The role of lipid peroxidation products and oxidative stress in activation of the canonical wingless-type MMTV integration site (WNT) pathway in a rat model of diabetic retinopathy

Our recent studies suggest that activation of the wingless-type MMTV integration site (WNT) pathway plays pathogenic roles in diabetic retinopathy and age-related macular degeneration. Here we investigated the causative role of oxidative stress in retinal WNT pathway activation in an experimental model of diabetes.

Strawberries decrease atherosclerotic markers in subjects with metabolic syndrome

Strawberries have been reported to be potent antioxidants and reduce cardiovascular risk factors, such as elevated blood pressure, hyperglycemia, dyslipidemia, and inflammation in limited studies. We hypothesized that freeze-dried strawberry supplementation will improve blood pressure, impaired glucose, dyslipidemia, or circulating adhesion molecules in obese subjects with metabolic syndrome, thereby lowering cardiovascular risk factors in these subjects. Twenty-seven subjects with metabolic syndrome (2 males and 25 females; body mass index, 37.5 +/- 2.15 kg/m(2); age, 47.0 +/- 3.0 years [means +/- SE]) consumed 4 cups of freeze-dried strawberry beverage (50 g freeze-dried strawberries approximately 3 cups fresh strawberries) or equivalent amounts of fluids (controls, 4 cups of water) daily for 8 weeks in a randomized controlled trial. Anthropometrics and blood pressure measurements, assessment of dietary intakes, and fasting blood draws were conducted at screen and 8 weeks of the study. Strawberry supplementation significantly decreased total and low-density lipoprotein cholesterol (5.8 +/- 0.2 to 5.2 +/- 0.2 mmol/L and 3.5 +/- 0.2 to 3.1 +/- 0.1 mmol/L, respectively [means +/- SE], P <.05) and small low-density lipoprotein particles using nuclear magnetic resonance-determined lipoprotein subclass profile vs controls at 8 weeks (794.6 +/- 94.0 to 681.8 +/- 86.0 nmol/L [means +/- SE], P <.05). Strawberry supplementation further decreased circulating levels of vascular cell adhesion molecule-1 vs controls at 8 weeks (272.7 +/- 17.4 to 223.0 +/- 14.0 ng/mL [means +/- SE], P <.05). Serum glucose, triglycerides, high-density lipoprotein cholesterol, blood pressure, and waist circumference were not affected. Thus, short-term freeze-dried strawberry supplementation improved selected atherosclerotic risk factors, including dyslipidemia and circulating adhesion molecules in subjects with metabolic syndrome, and these results need confirmation in future trials.

Berries:emerging impact on cardiovascular health

Berries are a good source of polyphenols, especially anthocyanins, micronutrients, and fiber. In epidemiological and clinical studies, these constituents have been associated with improved cardiovascular risk profiles. Human intervention studies using chokeberries, cranberries, blueberries, and strawberries (either fresh, or as juice, or freeze-dried), or purified anthocyanin extracts have demonstrated significant improvements in LDL oxidation, lipid peroxidation, total plasma antioxidant capacity, dyslipidemia, and glucose metabolism. Benefits were seen in healthy subjects and in those with existing metabolic risk factors. Underlying mechanisms for these beneficial effects are believed to include upregulation of endothelial nitric oxide synthase, decreased activities of carbohydrate digestive enzymes, decreased oxidative stress, and inhibition of inflammatory gene expression and foam cell formation. Though limited, these data support the recommendation of berries as an essential fruit group in a heart-healthy diet.

Freeze-dried strawberry powder improves lipid profile and lipid peroxidation in women with metabolic syndrome:baseline and post intervention effects

Strawberry flavonoids are potent antioxidants and anti-inflammatory agents that have been shown to reduce cardiovascular disease risk factors in prospective cohort studies. Effects of strawberry supplementation on metabolic risk factors have not been studied in obese populations. We tested the hypothesis that freeze-dried strawberry powder (FSP) will lower fasting lipids and biomarkers of oxidative stress and inflammation at four weeks compared to baseline. We also tested the tolerability and safety of FSP in subjects with metabolic syndrome. FSP is a concentrated source of polyphenolic flavonoids, fiber and phytosterols.