Relationship between pica and iron nutrition in Johannesburg black adults

On direct questioning by a Black staff nurse, 23% of 348 consecutive unselected adult outpatients attending the Johannesburg Non-European Hospital said that they regularly ate earth or ash. The prevalence was higher in the women (33%) than in the men (11 %), and in 50 women with minor gynaecological complaints who were interviewed by a Black psychologist, it was 72%. The quantity eaten varied from an occasional tablespoonful to several handfuls a day. In an attempt to define the reasons for the habit a thematic apperception test was used. A strong association with pregnancy was identified, but the explanation for this was not established. Some subjects claimed that the material was eaten for medicinal purposes, while others merely liked the taste. The effect on iron nutrition appeared to be variable, depending on the ironbinding capacity of the soluble iron content of the material consumed.S. Afr. Med. J., 48. 1655 (1974

Molecular interactions of Escherichia coli ExoIX and identification of its associated 3′–5′ exonuclease activity

The flap endonucleases (FENs) participate in a wide range of processes involving the structure-specific cleavage of branched nucleic acids. They are also able to hydrolyse DNA and RNA substrates from the 5′-end, liberating mono-, di- and polynucleotides terminating with a 5′ phosphate. Exonuclease IX is a paralogue of the small fragment of Escherichia coli DNA polymerase I, a FEN with which it shares 66% similarity. Here we show that both glutathione-S-transferase-tagged and native recombinant ExoIX are able to interact with the E. coli single-stranded DNA binding protein, SSB. Immobilized ExoIX was able to recover SSB from E. coli lysates both in the presence and absence of DNA. In vitro cross-linking studies carried out in the absence of DNA showed that the SSB tetramer appears to bind up to two molecules of ExoIX. Furthermore, we found that a 3′–5′ exodeoxyribonuclease activity previously associated with ExoIX can be separated from it by extensive liquid chromatography. The associated 3′–5′ exodeoxyribonuclease activity was excised from a 2D gel and identified as exonuclease III using matrix-assisted laser-desorption ionization mass spectrometry

Galaxy Cluster Scaling Relations between Bolocam Sunyaev-Zel'dovich Effect and Chandra X-ray Measurements

We present scaling relations between the integrated Sunyaev-Zel'dovich Effect (SZE) signal, $Y_{\rm SZ}$, its X-ray analogue, $Y_{\rm X}\equiv M_{\rm gas}T_{\rm X}$, and total mass, $M_{\rm tot}$, for the 45 galaxy clusters in the Bolocam X-ray-SZ (BOXSZ) sample. All parameters are integrated within $r_{2500}$. $Y_{2500}$ values are measured using SZE data collected with Bolocam, operating at 140 GHz at the Caltech Submillimeter Observatory (CSO). The temperature, $T_{\rm X}$, and mass, $M_{\rm gas,2500}$, of the intracluster medium are determined using X-ray data collected with Chandra, and $M_{\rm tot}$ is derived from $M_{\rm gas}$ assuming a constant gas mass fraction. Our analysis accounts for several potential sources of bias, including: selection effects, contamination from radio point sources, and the loss of SZE signal due to noise filtering and beam-smoothing effects. We measure the $Y_{2500}$--$Y_{\rm X}$ scaling to have a power-law index of $0.84\pm0.07$, and a fractional intrinsic scatter in $Y_{2500}$ of $(21\pm7)\%$ at fixed $Y_{\rm X}$, both of which are consistent with previous analyses. We also measure the scaling between $Y_{2500}$ and $M_{2500}$, finding a power-law index of $1.06\pm0.12$ and a fractional intrinsic scatter in $Y_{2500}$ at fixed mass of $(25\pm9)\%$. While recent SZE scaling relations using X-ray mass proxies have found power-law indices consistent with the self-similar prediction of 5/3, our measurement stands apart by differing from the self-similar prediction by approximately 5$\sigma$. Given the good agreement between the measured $Y_{2500}$--$Y_{\rm X}$ scalings, much of this discrepancy appears to be caused by differences in the calibration of the X-ray mass proxies adopted for each particular analysis.Comment: 31 pages, 15 figures, accepted by ApJ 04/11/2015. This version is appreciably different from the original submission: it includes an entirely new appendix, extended discussion, and much of the material has been reorganize

Calculating the transfer function of noise removal by principal component analysis and application to AzTEC observations

Instruments using arrays of many bolometers have become increasingly common in the past decade. The maps produced by such instruments typically include the filtering effects of the instrument as well as those from subsequent steps performed in the reduction of the data. Therefore interpretation of the maps is dependent upon accurately calculating the transfer function of the chosen reduction technique on the signal of interest. Many of these instruments use non-linear and iterative techniques to reduce their data because such methods can offer improved signal-to-noise over those that are purely linear, particularly for signals at scales comparable to that subtended by the array. We discuss a general approach for measuring the transfer function of principal component analysis (PCA) on point sources that are small compared to the spatial extent seen by any single bolometer within the array. The results are applied to previously released AzTEC catalogues of the COSMOS, Lockman Hole, Subaru XMM-Newton Deep Field, GOODS-North and GOODS-South fields. Source flux density and noise estimates increase by roughly +10 per cent for fields observed while AzTEC was installed at the Atacama Submillimeter Telescope Experiment and +15-25 per cent while AzTEC was installed at the James Clerk Maxwell Telescope. Detection significance is, on average, unaffected by the revised technique. The revised photometry technique will be used in subsequent AzTEC releases.Comment: 14 pages, 4 figure

High Spectral Resolution Measurement of the Sunyaev–Zel'dovich Effect Null with Z-Spec

The Sunyaev-Zel'dovich (SZ) effect spectrum crosses through a null where ΔT_CMB = 0 near ν_0 = 217 GHz. In a cluster of galaxies, ν0 can be shifted from the canonical thermal SZ effect value by corrections to the SZ effect scattering due to the properties of the inter-cluster medium. We have measured the SZ effect in the hot galaxy cluster RX J 1347.5 – 1145 with Z-Spec, an R ~ 300 grating spectrometer sensitive between 185 and 305 GHz. These data comprise a high spectral resolution measurement around the null of the SZ effect and clearly exhibit the transition from negative to positive ΔT_CMB over the Z-Spec band. The SZ null position is measured to be ν_0 = 225.8 ± 2.5(stat.) ± 1.2(sys.) GHz, which differs from the canonical null frequency by 3.0σ and is evidence for modifications to the canonical thermal SZ effect shape. Assuming the measured shift in ν0 is due only to relativistic corrections to the SZ spectrum, we place the limit kT_e = 17.1 ± 5.3 keV from the zero-point measurement alone. By simulating the response of the instrument to the sky, we are able to generate likelihood functions in {y_0, T_e, v_pec} space. For v_pec = 0 km s^(–1), we measure the best-fitting SZ model to be y_0 = 4.6^(+0.6)_(–0.9) × 10^(–4), T_e, 0 = 15.2^(+12)_(–7.4) keV. When v pec is allowed to vary, a most probable value of v_pec = + 450 ± 810 km s^(–1) is found

Is the Hexacyanoferrate(II) Anion Stable in Aqueous Solution? A Combined Theoretical and Experimental Study

A combined theoretical and experimental study was performed to elucidate the structural and dynamical properties of the isolated aqueous hexacyanoferrate(II) ion as well as in the presence of potassium counterions. It is shown that in absence of counterions, the highly negatively charged hexacyanoferrate(II) complex is not stable in aqueous solution. However, if the high negative charge is compensated by potassium counterions, a stable complex is observed, which is proven by theoretical simulations as well as by extended X-ray absorption fine structure (EXAFS) experiments. From the simulation it is found that potassium ions surrounding the complex are highly mobile and thus cannot be observed via EXAFS experiments. The structure of aqueous hexacyanoferrate(II) in the presence of potassium ions is identical to that of the solid-state structure, but the mobility of potassium ions is significantly increased in the liquid. These highly mobile potassium ions circulating the complex are the reason for the very short lifetime of hydrogen bonds between solvent water molecules and cyanide ligands being on the femtosecond scale

Microwave Kinetic Inductance Detector (MKID) Camera Testing for Submillimeter Astronomy

Developing kilopixel focal planes for incoherent submm- and mm-wave detectors remains challenging due to either the large hardware overhead or the complexity of multiplexing standard detectors. Microwave kinetic inductance detectors (MKIDs) provide a efficient means to produce fully lithographic background-limited kilopixel focal planes. We are constructing an MKID-based camera for the Caltech Submillimeter Observatory with 576 spatial pixels each simultaneously sensitive in 4 bands at 230, 300, 350, and 400 GHz. The novelty of MKIDs has required us to develop new techniques for detector characterization. We have measured quasiparticle lifetimes and resonator Qs for detector bath temperatures between 200 mK and 400 mK. Equivalent lifetime measurements were made by coupling energy into the resonators either optically or by driving the third harmonic of the resonator. To determine optical loading, we use both lifetime and internal Q measurements, which range between 15,000 and 30,000 for our resonators. Spectral bandpass measurements confirm the placement of the 230 and 350 GHz bands. Additionally, beam maps measurements conform to expectations. The same device design has been characterized on both sapphire and silicon substrates, and for different detector geometries. We also report on the incorporation of new shielding to reduce detector sensitivity to local magnetic fields

Active site substitutions delineate distinct classes of eubacterial flap endonuclease

FENs (flap endonucleases) play essential roles in DNA replication, pivotally in the resolution of Okazaki fragments. In eubacteria, DNA PolI (polymerase I) contains a flap processing domain, the N-terminal 5′→3′ exonuclease. We present evidence of paralogous FEN-encoding genes present in many eubacteria. Two distinct classes of these independent FEN-encoding genes exist with four groups of eubacteria, being identified based on the number and type of FEN gene encoded. The respective proteins possess distinct motifs hallmarking their differentiation. Crucially, based on primary sequence and predicted secondary structural motifs, we reveal key differences at their active sites. These results are supported by biochemical characterization of two family members - ExoIX (exonuclease IX) from Escherichia coli and SaFEN (Staphylococcus aureus FEN). These proteins displayed marked differences in their ability to process a range of branched and linear DNA structures. On bifurcated substrates, SaFEN exhibited similar substrate specificity to previously characterized FENs. In quantitative exonuclease assays, SaFEN maintained a comparable activity with that reported for PolI. However, ExoIX showed no observable enzymatic activity. A threaded model is presented for SaFEN, demonstrating the probable interaction of this newly identified class of FEN with divalent metal ions and a branched DNA substrate. The results from the present study provide an intriguing model for the cellular role of these FEN sub-classes and illustrate the evolutionary importance of processing aberrant DNA, which has led to their maintenance alongside DNA PolI in many eubacteria