SF Values Research Articles

MOLECULAR AND ATOMIC LINE SURVEYS OF GALAXIES. II. UNBIASED ESTIMATES OF THEIR STAR FORMATION MODE

We make use of our 'minimal' cold interstellar medium (ISM) emission line model that predicts the molecular and atomic line emission per unit dense, star-forming gas mass (Geach & Papadopoulos 2012; Paper I) to examine the utility of key line ratios in surveys of the so-called star formation 'mode' as traced by xi_SF = M_dense(H_2)/M_total(H_2). We argue that xi_SF and its proxies provide very sensitive, extinction-free discriminators of rapid starburst/merger-driven versus secular quiescent/disk-like stellar mass assembly, with the most promising diagnostic to be applied in the near-future being CO(4-3)/[CI](1-0). These lines are accessible across nearly the full range 0<z<2 (thus covering the bulk of galaxy evolution) with the Atacama Large Millimeter Array. In addition to their diagnostic power, another advantage of this combination is the similar observed frequencies (Delta nu_0 ~ 30 GHz) of the lines, resulting in nearly spatially-matched beams for a fixed aperture, thus mitigating the effects of resolution/morphology bias in the interpretation of galaxy-averaged line ratios. Finally we discuss the capability of deep blind redshift surveys with the high frequency component of the Square Kilometer Arrray (SKA) in discovering H_2-rich galaxies with very low xi_SF values. These could be the progenitors of starburst galaxies seen prior to the onset of star formation; such galaxies could be a class of extreme outliers from local (gas surface density)-(star formation rate) scaling laws, which would exclude them from current star formatation or stellar mass selected samples. Our conservative model suggests that SKA could detect such systems residing at z~3 at a rate of 20-200 per hour.

Bivariate Mixture Models of Serum Ferritin and Transferrin Saturation Predict Stable Components Measured 12 Years Apart in a Healthy Australian Population

Abstract 5281Bivariate mixture modeling was used to analyze joint population distributions of transferrin saturation (TS) and serum ferritin concentration (SF) measured in the Hemochromatosis and Iron Overload Screening (HEIRS) Study (McLaren et al.Translational Research 2008 151(2), 97−109). Four components (C1, C2, C3, and C4) were identified with successively age−adjusted increasing means for TS and SF from data contributed by 26,832 African Americans, 12,620 Asians, 12,264 Hispanics, and 43,254 whites. We used data from the Australian “HealthIron” study of genetic and environmental modifiers of hereditary hemochromatosis to validate the mixture model approach for component analysis and to determine whether the component distributions appear to be stable over time or whether an individual’s TS and SF values move from one component to another. Between 2004−2006, a sample of participants of northern European descent was selected from the Melbourne Collaborative Cohort Study (n=31,192 (17,951 women) recruited 1990–1994) to participate in the HealthIron study (n=1,438 (783 women)). Of these, 1,052 (579 women) participated in CAPI interviews and clinical examination. We applied the bivariate mixture modeling approach to TS and SF data from HealthIron. Follow−up data were excluded for individuals who were treated after baseline evaluations. The EMMIX program was used to predict component membership for HealthIron participants using the model based on the HEIRS data alone. Component transition probabilities over time were estimated as observed proportions. Analyses were performed separately for baseline and follow−up data. Four components (C1, C2, C3, C4) with successively age−adjusted increasing means for TS and SF, were identified using baseline data from 926 whites (426 men, 500 women) and using follow−up data from 771 whites (341 men, 430 women). At baseline, the largest component, C2, had normal mean TS (28% for women, 35% for men) and SF (139 mg/L for women, 309 μg/L for men), higher than the upper 95% confidence limits for means in analyses of HEIRS data. At follow−up, the largest component, C2, had normal mean TS (29% for women, 33% for men) and SF (124 μg/L for women, 183 μg/L for men) consisting of component proportions 0.64 for women and 0.72 for men. C3 and C4 had progressively higher mean values for TS and SF with progressively lower component proportions. At baseline, C1 had mean TS values of 15% for women (27% for men), and mean SF values of 23 mg/L for women (59 mg/L for men), similar to those found using HEIRS data. At follow−up, C1 had mean TS values of 18% for women and men, and mean SF values of 21 μg/L for women and 20 μg/L for men. Only female C282Y homozygotes for the iron gene, HFE, showed evidence that component transition probabilities shifted significantly over time;19 of 49 (39%) had TS and SF values that were in the same bivariate component at baseline and follow−up (Test of Symmetry, p=0.014). As for analyses of data from the HEIRS Study, a mixture of four components was found in data from HealthIron participants suggesting that the model is transferable from one white population to another, although estimated means within components may differ. The longitudinal aspect of this study illustrates that, with the exception of female C282Y homozygotes, the components of the mixture distributions are largely stable over time. Disclosures:No relevant conflicts of interest to declare.

Microstructure dependence of the c-axis critical current density in second-generation YBCO tapes

C-axis current flow in high temperature superconductor (HTS) tape-shaped wires arises in configurations where the local wire axis is not perpendicular to the local magnetic field, such as in power cables with helically wound HTS tapes. The c-axis critical current density Jcc has been recently found to be orders of magnitude lower than the ab-plane critical current density Jcab. Here we report on Jcc (77 K, sf) values of various YBa2Cu3O7-based (YBCO) tapes with different microstructures. Our results show that the value of Jcc (77 K, sf) decreases significantly with increasing concentration of ab-plane stacking faults in YBCO thin films and that the critical current anisotropy γ = Jcab/Jcc can reach values as high as 2070, implying that in the highest-anisotropy tape, ∼20% of the tape width carries c-axis current in a helically wound power cable.

Suppression of vascular endothelial growth factor via siRNA interference modulates the biological behavior of human nasopharyngeal carcinoma cells

The aim was to study the effect of vascular endothelial growth factor (VEGF) down-regulation by small interfering (si)RNA-mediated interference (RNAi) on the biological features of nasopharyngeal carcinoma cell line CNE-2. The combined plasmids pU-siVEGF and pU-siCONT were transfected into CNE-2 cells with lipofectamine. The transfected cells were placed in fresh medium containing G418. Expression of VEGF mRNA and protein were measured by reverse transcriptase-polymerase chain reaction and Western blot, respectively. The transwell chamber model was employed to test the ability of cell invasion in vitro. The distribution of cell cycle phases was determined by flow cytometry. Cell survival was assessed by clonogenic assays. Both VEGF mRNA and protein expression were significantly decreased in the pU-siVEGF group compared with controls (P < 0.05). The cell cycle was arrested in the G(1) phase (P < 0.05). A higher apoptotic ratio and lower invasion ability were seen in the pU-siVEGF group. The D(0) (mean lethal dose) and SF(2) values were significantly lower than those in the control group (P < 0.05). Delivery of siRNA targeting VEGF seems efficient in down-regulating VEGF expression and diminishing the growth, proliferation, and invasiveness of CNE-2 cells. It also enhanced the sensitivity of CNE-2 cells to radiation.

Photo- and electro-chromic organometallics with dithienylethene (DTE) linker, L2CpM-DTE-MCpL2: Dually stimuli-responsive molecular switch

Photochromic dithienylethene (DTE) derivatives, M-DTE-M (M: M(η(5)-C(5)R(5))L(2); M = Fe, Ru; R = H, Me; L = CO, phosphine), with direct σ-bonded, redox-active organometallic attachments are prepared and their response to photo- and electro-chemical stimuli as well as wire-like and switching performance has been investigated. These properties turn out to be dependent on the metal and the auxiliary ligands. The DTE complexes with the MCp(CO)(2) and RuCp(CO)(PPh(3)) fragments undergo reversible photochemical ring-closing and -opening of the DTE moiety upon UV and visible-light irradiation, respectively, whereas the other FeCp(CO)(PPh(3)) and Fe(η(5)-C(5)R(5))(dppe) derivatives are virtually inert with respect to the photochemical ring closing process. Electrochemical analysis of the DTE complexes reveals that 2e-oxidation of the open isomer O also brings about the ring closure of the DTE moiety to afford the Fischer-carbene-type, dicationic closed derivatives C(2+) with the π-conjugated system different from that in the neutral ones C obtained photochemically. Subsequent reduction of C(2+) furnishes the neutral closed species C. Thus the ring closure is mediated not only by the conventional photochemical process but also by the sequential oxidation-reduction process, i.e. the organometallic DTE complexes are found to be dually photo- and electro-chromic. It is notable that the oxidative procedures are viable for the photochemically inert derivatives. Wire-like and switching performance has been evaluated on the basis of the comproportionation constant K(C) for the 1e-oxidized mixed valence monocationic species obtained by the electrochemical analysis and the switching factor SF (K(C)(C)/K(C)(O)), respectively. The K(C)(C) (7.5 × 10(4)) and SF values (5.4 × 10(3)) for phosphine-substituted derivatives are significantly large, as a result of the distinct π-conjugated systems of the DTE moieties involved in the O- (with cross-conjugation) and C-forms (fully conjugated). Compared to the previously reported acetylide-type complexes bridged by a DTE linker, (dppe)Cp*M-C≡C-DTE-C≡C-MCp*(dppe), both parameters have been significantly improved by factors of ~150. Time-dependent DFT analysis for the photochemical processes has revealed that the ring-closing process occurs not only via the ligand centered singlet excited state but also via the ligand centered triplet state resulting from energy transfer processes between the ligand- and metal-centered excited states and that this proposed mechanism can account for the photochemical reactivity of ruthenium complexes superior to that of the corresponding iron derivatives.

Attention to hierarchical level influences attentional selection of spatial scale.

Ample evidence suggests that global perception may involve low spatial frequency (LSF) processing and that local perception may involve high spatial frequency (HSF) processing (Shulman, Sullivan, Gish, & Sakoda, 1986; Shulman & Wilson, 1987; Robertson, 1996). It is debated whether SF selection is a low-level mechanism associating global and local information with absolute LSF and HSF content, or whether it is a higher level mechanism involving a selective process that defines the SF range in which global and local can then be relatively defined. The present study provides support for the latter claim by demonstrating that allocating attention to global or local levels of hierarchical displays biased selection of LSFs or HSFs, respectively, in subsequently presented compound gratings. This bias occurred despite a change in the response dimension (from letter identification in the hierarchical stimulus to orientation discrimination in the grating) and despite a difference in retinal location of the hierarchical stimuli and the grating stimulus. Moreover, the bias was determined by the relationship between the 2 SFs in the compound grating (i.e., their relative frequency) rather than the absolute SF values.

Scattering factor evaluation and study of medical intervention following intake of 60Co

Guidelines for the assessment of internal doses from monitoring suggest default measurement of uncertainties (i.e. lognormal scattering factor, SF) to be used for different types of monitoring data. In this paper, SF values have been evaluated for internal contamination due to 60Co in two cases using whole body counting data. SF values of 1.04 and 1.03 were obtained for case I and II, respectively while SF value of 1.03 was obtained using bioassay data for case I. SF evaluated is in good agreement with the default values given by IDEAS guidelines. The present study also presents the follow up study of a case I of 60Co internal contamination using whole body counting and bioassay analysis. The effect of medical intervention applied on the subject is studied. Medical intervention of d-Penicillamine (250 mg × 4 daily) was orally administered from 13th day of initial exposure for about a fortnight, which showed reduction of activity present by 33.4% through urine.

Attention to hierarchical level influences attentional selection of spatial scale

Ample evidence suggests that global perception may involve low spatial frequency (LSF) processing and that local perception may involve high spatial frequency (HSF) processing (Shulman, Sullivan, Gish, & Sakoda, 1986; Shulman & Wilson, 1987; Robertson, 1996). It is debated whether SF selection is a low-level mechanism associating global and local information with absolute LSF and HSF content, or whether it is a higher level mechanism involving a selective process that defines the SF range in which global and local can then be relatively defined. The present study provides support for the latter claim by demonstrating that allocating attention to global or local levels of hierarchical displays biased selection of LSFs or HSFs, respectively, in subsequently presented compound gratings. This bias occurred despite a change in the response dimension (from letter identification in the hierarchical stimulus to orientation discrimination in the grating) and despite a difference in retinal location of the hierarchical stimuli and the grating stimulus. Moreover, the bias was determined by the relationship between the 2 SFs in the compound grating (i.e., their relative frequency) rather than the absolute SF values.

Elevated Serum Hepcidin in Patients with AML Prior to and After Allogeneic Hematopoietic Cell Transplantation Does Not Correlate with Transfusional Body Iron, HFE Genotype or Graft Versus Host Disease and May Protect From Excessive Parenchymal Iron Loading.

Abstract 4047Poster Board III-982Hepcidin (hep), a 25-amino-acid peptide, is the central regulator of iron homeostasis. Its transcription is upregulated by inflammatory cytokines and iron and is downregulated by iron deficiency, ineffective erythropoiesis, and hypoxia. Also HFE gene mutations are associated with less liver hepcidin messenger RNA. Both inherited (HFE genotype) and treatment-related factors influencing hep expression in patients (pts) with AML prior to and after allogeneic hematopoietic cell transplantation (HCT) as blood transfusions (BT), body iron and anemia were studied. The impact of chemotherapy, conditioning regimen, and Graft versus Host Disease (GvHD) on serum hep was analysed. Patients and methods42 consecutive pts (23 male/19 female, median age 57 [range:18-70] years) with AML who underwent allogeneic HCT from February, 2008 - February, 2009 at the University of Leipzig were included. Each patient was assessed 10 days prior to and at a median of 3 (range: 3-5) months after HCT. Donors were matched related in 8 (19%) and matched unrelated (MUD) in 34 (81%) pts. Preparative regimen consisted of 12 Gy TBI/cyclophosphamid 120 mg/kg (ATG was included for unrelated HCT) in 13 (31%) and fludarabin 30 mg/m2/day for 3 days/2 Gy TBI) in 29 (69%) pts. Acute GvHD > grade II was present in 13 (31%) and chronic GvHD in 17 (40%) pts. HFE genotype prior to and after HCT was assessed by PCR technique. Body iron was assessed by serum ferritin (sf) (normal values < 400ng/mL). Serum hep was measured by hepcidin C-ELISA at Intrinsic LifeSciences LLC, La Jolla, CA.(normal values: male 29-254 ng/mL, female: 17-286 ng/mL). Hep levels of 21 age-and gender-matched healthy volunteers (6 m/15 f, median age 57 years) were used as a control. ResultsMedian serum hep was much higher in pts both prior to [median 358 (range:56-1096) ng/ml] and after HCT [median 398 (range:172-941) ng/ml] compared with the control group [median 52 (range:8.3-131) ng/ml] (p<0.0001). Age and gender had no influence on hep values. Similarly, liver function, interval between diagnosis and HCT, number of chemotherapies, conditioning regimen, antibiotic- or antifungal-treatments had no impact on hep level. Iron overload was already seen in all pts prior to HCT with a median sf of 1945 (range: 617-6981) ng/mL after a median number of 22 units BT. Although after HCT the number of BT mounted to a median of 30 units (p<0.0001), sf with a median of 2260 ng/mL remained elevated comparable to the level prior to HCT. Lower hep levels significantly correlated with fewer BT (p=0.001), but surprisingly not with sf values. Hep correlated inversely with the degree of anemia (p=0.002). Mutations in the HFE gene were found in 19 (46%) pts prior to HCT (heterozygosity (het) for H63D, n=11, het C282Y, n=3, het S65C, n=1, and homozygosity (homo) for H63D, n=4) and in 15 (37.5%) pts after HCT reflecting donor genotype (het for H63D,n=12, het C282Y, n=1, compound-het, n=1). Mutations in the HFE gene were not associated with lower hep levels.After HCT, 19 (45%) pts showed a decline in hep level of 155 (range: 394.8-9.5) ng/ml and 23 (55%) pts had an increase in hep levels of 138 (range: 43.3- 620.9) ng/ml compared with pre-transplantaion levels. None of the above mentioned parameters could predict or correlate with these changes in serum hep. Iron overload prior to HCT strongly correlated with later extensive chronic GvHD (p=0.003) and tended to correlate with limited GvHD (p=0.06). On the other hand, hep levels at any time point did not correlate with acute or later chronic GvHD. ConclusionsSerum hepcidin is highly elevated in pts with AML prior to as well as after allogeneic HCT compared with healthy controls mainly because of frequent blood transfusions leading to elevated iron stores. This suggests that hepcidin synthesis and upregulation remain intact despite intensive chemotherapy and HCT. Hepcidin normally binds to ferroportin, leading to intracellular retention of iron in macrophages and to a reduction of extracellular serum iron. This may explain why serum hepcidin correlates with blood transfusions but not with serum ferritin values. Actually, overexpression of hepcidin may play an important protective role in this setting as it may prevent an increased ferroportin-mediated iron export from macrophages thereby reducing the severity of parenchymal iron loading and damage. Disclosures:Westerman:INTRINSIC LIFESCIENCES LLC: Consultancy, Employment, Equity Ownership. Hehme:Novartis: Employment. Niederwieser:Novartis: Speakers Bureau. Al-Ali:Novartis: Research Funding.

Conformer determination of stabilized triphenyl phosphonium acyl ylides by infrared spectroscopy

Stretching frequencies of acyl groups of stabilized triphenyl phosphonium ylides with ester, keto or cyano groups depend in part on the orientations of the acyl groups, syn or anti, with respect to phosphorus. Frequencies predicted by ab initio HF methods are higher than observed, and for diesters and diketones are higher for anti than syn acyl groups. For diester and diketo ylides and their cyano derivatives a Scale Factor, SF, of 0.866, fits much of the data with HF/6-31G(d) calculations, although it is lower than the literature value. The literature SF values for DFT methods, e.g., BLYP/6-31G(d) and B3LYP/6-31G(d), are closer to unity, and agreement with experiment is reasonable, except that for mixed anti isopropyloxy or t-butyloxy and syn methoxy or ethoxy diester ylides predicted stretching frequencies of the syn acyl groups by BLYP are too low, and fits are worse than with HF/6-31G(d), but B3LYP gives satisfactory results. The combination of ab initio methods and determination of IR acyl stretching frequencies may be useful when structure determination of stabilized ester, keto and cyano ylides by X-ray crystallography is not feasible, or when conformer interconversion in solution is too fast for use of NMR spectroscopy.

Natriuretic Peptides as Well as Endothelin, and Not Troponin Are of Value in Early Diagnosis of Acute Cardiotoxicity in Children Undergoing Hematopoietic Stem Cell Transplantation

The incidence of cadiotoxicity (CT) has been estimated at 5–10% of adult patients following hematopoietic stem cell transplantation (HSCT), but it is unknown in patients undergoing HSCT in childhood. Recent studies showed several biochemical markers as potentially useful for early detection of CT: Atrial Natriuretic Peptide (ANP) secreted by the atria in response to stretch as a result of an increased left atrial pressure, N-terminal fragment of Brain Natriuretic Peptide (NT-proBNP) produced by ventricles in response to ventricular dilatation and increased wall stress, cardiac Troponin I (TnI) the thin-filament contractile protein released to the circulation after myocardial injury and Endothelin 1 (ET-1) a vasoconstrictor peptide synthesized in the vasculature and by the endothelial cells and ventricular myocytes. The aim of the study was to assess the frequency and significance of elevated NT-proBNP, ANP, ET-1 and TnI plasma levels and their correlation to echocardiographic parameters of left ventricular function: shortening fraction (FS) and ejection fraction (EF) in children in early postransplant period. Patients: A total number of 31 consecutive children (22 boys and 9 girls) with median age of 9.6 years (range 0–18), treated with HSCT were included in the study: 12 autologous (aHSCT), 9 unrelated donor (MUD HSCT) and 10 family donor (MSD HSCT) transplantations were performed. The control group consisted of 14 healthy children, with median age of 10.9 years.Methods: The plasma levels of NT-proBNP, ANP and ET-1 were measured in transplanted patients on days −7, 0, +7, +14 by the Electrochemiluminescent Immunoassay (Biomedica) and TnI by the Immunoassay (Abbot). SF and EF were assessed by echocardiography prior to HSCT and about day +30 and +100 after transplantation. The same tests were performed in the control group. Results: Baseline echocardiographic parameters were within the normal range in all patients included in the study. In comparison with a control group, a trend to decrease median SF and EF values was observed on day +30 (FS > 28% and EF > 55%). In transplanted patients median ET-1 plasma levels were elevated in all analyzed time points when compared to controls (p< 0.05); median NT pro-BNP plasma concentrations were significantly elevated from days −7 to +7 (p< 0.05) and median ANP plasma concentrations on day +7 (p< 0.05). Median levels of TnI did not differ between analyzed and control groups. No correlation was found between elevated biochemical marker levels and echocardiographic parameters evaluated on days +30 and +100 after HSCT. According to the type of transplant, in aHSCT patients ET-1 plasma level elevation was observed in 4 analyzed time points (p< 0.05), while in MUD transplant recipients on day +7 only and in MSD transplant recipients on day +14 only. NT pro-BNP and ANP plasma levels were elevated in MUD transplant recipients on days 0,+7, +14 (p<0.05), in MSD patients on day +7, while in aHSCT patients no difference was found, when compared to controls. The levels of TnI did not differ between patients and controls in any transplant type. Statistically significant correlation was found between ANP level on day +14 and EF on day +100 in MUD patients and in aHSCT patients (r = −0.9 and r = −0.78 respectively).Conclusions: Elevation of natriuretic peptides (ANP, NT-proBNP) levels may indicate the risk of cardiotoxicity, especially in unrelated transplant recipients. ET-1 plasma concentration is elevated mainly in children following autologous transplantation. The value of measuring TnI levels in the assessment of CT in children following HSCT is low. Further studies are necessary to confirm the role of natriuretic peptides and ET-1 as markers of acute CT regarding the type of transplant.

Flexural and diametral tensile strength of composite resins

This study evaluated the flexural strength (sf) and the diametral tensile strength (st) of light-cured composite resins, testing the hypothesis that there is a positive relation between these properties. Twenty specimens were fabricated for each material (Filtek Z250- 3M-Espe; AM- Amelogen, Ultradent; VE- Vit-l-escence, Ultradent; EX- Esthet-X, Dentsply/Caulk), following ISO 4049 and ANSI/ADA 27 specifications and the manufacturers instructions. For the st test, cylindrical shaped (4 mm x 6 mm) specimens (n = 10) were placed with their long axes perpendicular to the applied compressive load at a crosshead speed of 1.0 mm/min. The sf was measured using the 3-point bending test, in which bar shaped specimens (n = 10) were tested at a crosshead speed of 0.5 mm/min. Both tests were performed in a universal testing machine (EMIC 2000) recording the fracture load (N). Strength values (MPa) were calculated and statistically analyzed by ANOVA and Tukey (a = 0.05). The mean and standard deviation values (MPa) were Z250-45.06 +/- 5.7; AM-35.61 +/- 5.4; VE-34.45 +/- 7.8; and EX-42.87 +/- 6.6 for st; and Z250-126.52 +/- 3.3; AM-87.75 +/- 3.8; VE-104.66 +/- 4.4; and EX-119.48 +/- 2.1 for sf. EX and Z250 showed higher st and sf values than the other materials evaluated (p < 0.05), which followed a decreasing trend of mean values. The results confirmed the study hypothesis, showing a positive relation between the material properties examined.

Bivariate mixture modeling of transferrin saturation and serum ferritin concentration in Asians, African Americans, Hispanics, and whites in the Hemochromatosis and Iron Overload Screening (HEIRS) Study

Bivariate mixture modeling was used to analyze joint population distributions of transferrin saturation (TS) and serum ferritin concentration (SF) measured in the Hemochromatosis and Iron Overload Screening (HEIRS) Study. Four components (C1, C2, C3, and C4) with successively age-adjusted increasing means for TS and SF were identified in data from 26,832 African Americans, 12,620 Asians, 12,264 Hispanics, and 43,254 whites. The largest component, C2, had normal mean TS (21% to 26% for women, 29% to 30% for men) and SF (43-82 microg/L for women, 165-242 microg/L for men), which consisted of component proportions greater than 0.59 for women and greater than 0.68 for men. C3 and C4 had progressively greater mean values for TS and SF with progressively lesser component proportions. C1 had mean TS values less than 16% for women (<20% for men) and SF values less than 28 microg/L for women (<47 microg/L for men). Compared with C2, adjusted odds of iron deficiency were significantly greater in C1 (14.9-47.5 for women, 60.6-3530 for men), adjusted odds of liver disease were significantly greater in C3 and C4 for African-American women and all men, and adjusted odds of any HFE mutation were increased in C3 (1.4-1.8 for women, 1.2-1.9 for men) and in C4 for Hispanic and white women (1.5 and 5.2, respectively) and men (2.8 and 4.7, respectively). Joint mixture modeling identifies a component with lesser SF and TS at risk for iron deficiency and 2 components with greater SF and TS at risk for liver disease or HFE mutations. This approach can identify populations in which hereditary or acquired factors influence metabolism measurement.

Serum ferritin and erythrocyte indices in iron overload.

Raised levels of serum transferrin saturation (TS) and ferritin (SF) are frequently associated with increased values of haemoglobin and erythrocyte indices. In hereditary haemochromatosis this phenomenon has been considered to be a beneficial effect of the C282Y mutation, protecting women from iron deficiency. The elevated values of mean corpuscular volume (MCV) in hereditary haemochromatosis may reflect increased iron uptake and haemoglobin synthesis by immature erythroid cells1–3. In a large screening study of a European population, a higher haemoglobin concentration was found in C282Y homozygous women with either normal or increased TS or SF4. However, when the effect of the C282Y mutation was analysed separately in subjects from different parts of Europe, the mean haemoglobin concentration and MCV were higher in C282Y carriers from northern Europe than in those from southern Europe. This could be due to the higher prevalence of thalassaemia trait in southern Europe5. The variability in TS and SF may depend not only on mutations in HFE or other genes involved in haemochromatosis, but also on other genetic and environmental factors. A recent large screening study (the HEIRS study) conducted in the USA and in Canada found higher mean TS and SF levels among Asians and Pacific Islanders, who do not have an HFE mutation or H63D allele, than in white subjects. There is no consistent evidence supporting the hypothesis that the increased SF in Asians is attributable to liver disease or diabetes. A reduced MCV in Asian men with increased SF could be explained by a high prevalence of thalassaemia trait in this population, although further studies are required to clarify this issue6. In anaemia of chronic diseases (ACD), normal or increased SF and reduced TS levels are usually associated with low haemoglobin levels and normocytic or microcytic erythrocytes. An increased uptake of iron and retention in active macrophages, which is the pathophysiological mechanism of ACD, is linked to increased pro-inflammatory and anti-inflammatory cytokines and is responsible for reduced availability of iron for erythroid progenitors. Recently, it was speculated that a small peptide hormone, hepcidin, might be involved in the pathogenesis of ACD. Hepcidin has antimicrobial activity and its expression increases in response to inflammatory stimuli. In mice, hepcidin mRNA expression is increased in response to lipopolysaccharides and infection. It has been suggested that hepcidin may be one cytokine-regulated gene that impairs erythrocyte iron acquisition by modifying the release of iron from macrophages7. In alcoholic steatosis, the serum TS and SF levels are unrelated to iron deposits. In alcoholic cirrhosis, low haemoglobin concentrations and increased MCV are often detected in association with increased levels of ferritin. These haematological findings are dependent on several factors, including direct and indirect effects of alcohol on the bone marrow, an impaired nutritional state, and the different stages of the liver disease. Hyperferritinaemia is also frequently observed in non-alcoholic fatty liver disease (NAFLD), the hepatic manifestation of the metabolic syndrome. The increased SF values are associated with insulin resistance and mild hepatic iron accumulation. So far, no significant modifications of haematological indices have been reported in NAFLD8.

Evaluation of scattering factor values for internal dose assessment following the IDEAS guidelines: preliminary results

The IDEAS Guidelines for the assessment of internal doses from monitoring data suggest default measurement uncertainties (i.e. scattering factors, SFs) to be used for different types of monitoring data. However, these default values were mainly based upon expert judgement. In this paper, SF values have been calculated for different radionuclides and types of monitoring data using real data contained in the IDEAS Internal Contamination Database. Results are presented.

Twinning and texture development in two Mg alloys subjected to loading along three different strain paths

The evolution of twinning and texture in two Mg-based (+Al, Mn, Zn) alloys was investigated using uniaxial tension, uniaxial compression and ring hoop tension testing at temperatures from ambient to 250 °C and a strain rate of 0.1 s −1. The results indicate that the initial extrusion texture plays an important role in the formation of different types of twins and that the twinning behavior also depends on the strain path. Contraction and double twinning are the dominant twinning mechanisms in uniaxial tension, while extension twinning prevails in uniaxial compression and ring hoop tension testing. Schmid factor analysis indicates that only components that are favorably oriented (i.e., with the highest SF values) can undergo rapid and complete twinning. The different twinning behaviors are shown to be responsible for the sharply contrasting strain hardening characteristics of the experimental flow curves and dramatic texture changes.

Liver Status in a Cohort of Polytransfused B-Thalassemia Major (BTM) on Long Term Desferrioxamine (DfO) or Deferiprone (L1).

The liver is the main body site for iron storage. Iron chelators as DFo and L1 had problems of compliance and intolerance respectively. This prospective study enrolled 76 BTM patients aged from 9–33 years, mean of 14±4.4 to evaluate the effectiveness of both chelators judged by serum ferritin (sf) and liver iron content (LIC) using repeated liver biopsies. Fifty patients were on DFo 35 mg/kg/day 5 days per week and twenty-six were on L1 75 mg/kg/day on daily bases. Mean baseline sf values were 3678±1922 and 3573±1879 ng/ml while mean baseline LIC was 19.2±7.9 and 18.9±8.1 mg fe/g dw, while 12% and 14% showed evidence of liver fibrosis (score ≥ 3) respectively. Twenty-four months later; a decline in sf by 287±837 in Dfo (In Dfo compliant group [number = 30]who had received ≥ 75% of planned dose; sf dropped by 890±437 while increased in DFo non compliant by 621±513). While falling by 729±633 in L1 group. A decrease in LIC by 3.9±2.8 mg fe/g dw (−5.8±3.1 in Dfo compliant,+2.6±3.3 in Dfo non compliant) and falling by 2.2±3.4 mg fe/g dw in L1 group, the difference was statistically significant P< 0.05 between compliant and non compliant DFo and insignificant difference between Dfo and L1.The mean iron excretion: intake was 1.61,0.86 and 1.48 in Dfo compliant, non compliant and L1 respectively. A positive correlation was found between sf and LIC in both groups. Fibrosis was improved in Dfo compliant group better than L1 but no statistically significant difference was observed, while progressive fibrosis in 10% of Dfo non compliant group. All Dfo compliant group completed study, 18 out of 20 Dfo non compliant while six L1 patients discontinued the drug prematurely (3 severe gastrointestinal disturbances, 2 severe arthralgia and one repeated neutropenia). Conclusion: Both Dfo and L1 are effective iron chelators evident by drop in sf, LIC and improved fibrosis, however compliance and intolerance are still troublesome.

Initial Screening Transferrin Saturation Values, Serum Ferritin Concentrations, andHFEGenotypes in Whites and Blacks in the Hemochromatosis and Iron Overload Screening Study

We compared initial screening data of 44,082 white and 27,124 black Hemochromatosis and Iron Overload Screening (HEIRS) Study participants. Each underwent serum transferrin saturation (TfSat) and ferritin (SF) measurements without regard to fasting, and HFE C282Y and H63D genotyping. Elevated measurements were defined as: TfSat more than 50% (men), more than 45% (women); and SF more than 300 ng/ml (men), more than 200 ng/ml (women). Mean TfSat and percentages of participants with elevated TfSat were significantly greater in whites than in blacks. Mean SF and percentages of participants with elevated SF were significantly greater in blacks than in whites. TfSat and SF varied by gender and age in whites and blacks. Prevalences of genotypes that included either C282Y or H63D were significantly greater in whites than in blacks. The prevalence of elevated TfSat and SF plus genotypes C282Y/C282Y, C282Y/H63D, or H63D/H63D was 0.006 in whites and 0.0003 in blacks. Among whites with HFE C282Y homozygosity, 76.8% of men and 46.9% of women had elevated TfSat and SF values. Three black participants had HFE C282Y homozygosity; one had elevated TfSat and SF values. Possible explanations for differences in TfSat and SF in whites and blacks and pertinence to the detection of hemochromatosis, iron overload, and other disorders with similar phenotypes are discussed.

Configurations of the Bentonite-Sorbed Myristylpyridinium Cation and Their Influences on the Uptake of Organic Compounds

Variations in the configuration of a sorbed myristylpyridinium (MP+) surfactant cation with a loading level in bentonite were examined by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR); the attractive force from the clay basal surfaces to the sorbed MP+ and water molecule in the interlayers was estimated by thermogravimetric analysis (TG-DTG). At low loading levels (i.e., < CEC), MP+ sorbed mainly by cation exchange to clay basal surfaces to form tightly-adhered "organic films" (i.e., flat-layer). With increasing MP+ loading, sorbed MP+ gradually changed into a less confined "phase-like medium" (i.e., paraffin-type structures) via London attraction forces. Attractive forces between the mineral basal surfaces and the sorbed MP+ varied with the interlayer spacing and the stacking of MP+. Sorption of phenol and naphthalene to the resultant MP(+)--clay was a function of the configuration of MP+ aggregates on clay surfaces. At low MP+ densities, the sorbed MP+ film acted as an effective adsorbent for organic compounds. The carbon-normalized solute distribution coefficients (K(sf)) were exceptionally large and increased with MP+ densities up to approximately 340 (phenol) and approximattely 15000 mL g(-1) (naphthalene). At high MP+ loadings, the MP+ aggregates transformed into a partition-like medium, and the K(sf) values decreased sharply and leveled off. Nonetheless, because of the enhanced MP+ packing density within the clay interlayer, the solute K(sf) with a confined sorbed MP+ phase exceeded the corresponding aqueous micelle-water partition coefficients (k(mc)).

Body composition predicted from skinfolds in African women: a cross-validation study using air-displacement plethysmography and a black-specific equation

Skinfold thickness (SF) measurements are commonly used for the indirect assessment of body composition. It is necessary to know how large the bias is when using Caucasian SF-based prediction equations Africans, as no specific equations exist. Our first aim was to test the validity of the equation of Durnin & Womersley for predicting body density from SF in Africans. The second aim was to determine the effect of calculating percentage body fat (%BF) from body density using a black-specific formula rather than the Siri equation, thus taking into account the higher fat-free mass (FFM) density in blacks than in whites. A total of 196 African women volunteered. Mean age was 29.5 (sd 8.7) years and mean BMI was 22.5 (sd 4.6) kg/m2. We compared body density values predicted from SF with those measured by air-displacement plethysmography, and %BF values obtained from body density using the Siri equation or the black-specific calculation. The bias (reference minus prediction) was 0.0100 kg/cm3 in body density (P<10(-4)) and 6.5 % BF (P<10(-4)), and the error (sd of the bias) 0.0097 kg/l and 4.5 % BF. With the black-specific equation, the bias was reduced by 1.9 % BF, while error remained similar. As the %BF prediction required an SF-based equation followed by a body density-based calculation, the lack of validity we observed in Africans may be due to known differences between blacks and whites in the distribution of subcutaneous adipose tissue and, as demonstrated, in the FFM density. Equations thus need to be established using SF values specific to Africans.