Prescription for healthy communities: community development finance

Public health - Economic aspects ; Community development

Orbital Magnetism of Graphene Nanostructures: Bulk and Confinement Effects

We consider the orbital magnetic properties of non-interacting charge carriers in graphene-based nanostructures in the low-energy regime. The magnetic response of such systems results both, frombulk contributions and from confinement effects that can be particularly strong in ballistic quantum dots. First we provide a comprehensive study of the magnetic susceptibility $\chi$ of bulk graphene in a magnetic field for the different regimes arising from the relative magnitudes of the energy scales involved, i.e. temperature, Landau level spacing and chemical potential. We show that for finite temperature or chemical potential, $\chi$ is not divergent although the diamagnetic contribution $\chi_{0}$ from the filled valance band exhibits the well-known $-B^{-1/2}$ dependence. We further derive oscillatory modulations of $\chi$, corresponding to de Haas-van Alphen oscillations of conventional two-dimensional electron gases. These oscillations can be large in graphene, thereby compensating the diamagnetic contribution $\chi_{0}$ and yielding a net paramagnetic susceptibility for certain energy and magnetic field regimes. Second, we predict and analyze corresponding strong, confinement-induced susceptibility oscillations in graphene-based quantum dots with amplitudes distincly exceeding the corresponding bulk susceptibility. Within a semiclassical approach we derive generic expressions for orbital magnetism of graphene quantum dots with regular classical dynamics. Graphene-specific features can be traced back to pseudospin interference along the underlying periodic orbits. We demonstrate the quality of the semiclassical approximation by comparison with quantum mechanical results for two exemplary mesoscopic systems, a graphene disk with infinite mass-type edges and a rectangular graphene structure with armchair and zigzag edges, using numerical tight-binding calculations in the latter case.Comment: 21 pages, 16 figure

Immune Boost, Early Pandemic

Immune Boost, Early Pandemic by Lisa Richte

The effect of dietary sulfur on performance, mineral status, rumen hydrogen sulfide, and rumen microbial populations in yearling beef steers

Sulfur (S) is a requisite part of the ruminant diet, but may sometimes be present in excess, leading to decreased animal performance and illness. In this experiment, 96 crossbred yearling steers (321 y 29 kg BW) were used to determine the effects of dietary S concentration of a supplement fed to cattle on pasture and of the total diet in the finishing period. Steers were blocked by weight and allocated to smooth bromegrass-based pastures and supplemented with either a low S dried distillers grains with solubles (DDGS; 0.3% total dietary S; LS; n = 4 plots) or LS DDGS with additional S (0.45% total dietary S; HS; n = 4 plots). After 36 d on pasture, steers moved to the feedlot where half remained on the previous S treatment while half switched treatments, resulting in 4 treatments (LS-LS; LS-HS; HS-LS; and HS-HS; n = 6 feedlot pens). Steers were transitioned to the final finishing diet using a series of step up diets. Once fully transitioned, steers were receiving either 0.3% dietary S (LS) or 0.6% dietary S (HS). Plasma and liver mineral concentrations of half of the steers were determined at beginning of the trial (d 0), the end of the pasture period (d 35), and near the end of study (d 155). Plasma Mg was decreased (P = 0.05) in response to increased dietary S during the pasture period, however steers were not deficient. Copper concentrations in the plasma and liver were decreased (P \u3c 0.05) in steers which had received increased dietary S when measured at the end of study (d 155). Average daily gain of steers did not differ (P = 0.50) between LS and HS during the pasture period, but was lower (P = 0.01) in HS vs. LS steers during the finishing period. Decreased gains translated to a tendency (P = 0.06) for hot carcass weight to be decreased in HS steers vs. LS steers. Fatty acid analysis of longissimus dorsi showed increased stearic and heptadecanoic acid (P = 0.04 and 0.01, respectively) in steers receiving increased dietary S. Cattle exposed to higher S diets during the pasture period did not show differences (P = 0.40) in performance based on the previous pasture treatment. However, cattle fed high dietary S on pasture had greater carcass fat cover (P = 0.01), suggesting S may have influenced lipid metabolism. Rumen H2S concentration was determined 6 hr post-feeding at multiple time points throughout transition and finishing (d 36, 45, 52, 59, 66, 91,125, and 155). Concentrations of rumen H2S did not differ while cattle were consuming a high forage diet (1733 and 1400 ppm for HS and LS, respectively; P = 0.54). During the feedlot period, rumen H2S concentration was affected by day of sampling (P \u3c 0.01). Rumen H2S began to differ due to treatment when forage in the diet decreased to 15% of diet DM (P = 0.04). This increase in H2S in HS cattle was sustained throughout the finishing period (P \u3c 0.05) when forage was present at 8% of DM. Peak H2S concentrations in HS steers were observed on d 91 when steers had been on the full finishing diet with 8% forage for 23 days (HS: 4813 ppm; LS: 1317 ppm; P \u3c 0.01) and again near the end of trial (d 155; HS: 5275 ppm; LS 1248 ppm; P \u3c 0.01). Rumen fluid was collected esophageally for determination of VFA and lactate proportions at the end of the pasture period (d 36), during transition (d 56) and near the end of study (d 155). Lactate proportion was not affected (P \u3e 0.50) by dietary S concentration and minimal effects on VFA profiles were observed. Isovalerate was decreased (P = 0.002) in cattle receiving elevated dietary S on d 155. Rumen fluid samples collected near the end of study (d 155) from steers which represented treatments maintained on the same S treatment throughout the study (LS-LS and HS-HS, n = 6 pens per treatment) were analyzed for sulfate reducing bacteria (SRB) populations and methanogens using quantitative real time PCR. Steers receiving the HS diet demonstrated an increase (P = 0.03) in total SRB and an increase (P = 0.03) in a SRB group which represents the SRB most commonly found in the rumen, specifically Desulfovibrio desulfuricans . The simple correlation between SRB populations and H2S concentrations (R = 0.60, P = 0.05) illustrates that a considerable portion of the variation in H2S concentrations among cattle may be accounted for by the differences in SRB populations. These combined effects of dietary S concentration on rumen H2S concentration, VFA proportions, and microbial populations illustrate that rumen metabolism is altered by increased dietary S. Furthermore, these effects on rumen metabolism may partially explain the decreases in performance, evidenced by reduced gains, and HCW, while part of the decrease in performance may also be explained by effects of increased dietary S on mineral status, especially Cu

HDAC1 is a Required Cofactor of CBFβ-SMMHC and a Therapeutic Target in Inversion 16 Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a neoplastic disease characterized by the uncontrolled proliferation and accumulation of immature myeloid cells. A common mutation in AML is the inversion of chromosome 16 [inv(16)], which generates a fusion between the genes for core binding factor beta (CBFB) and smooth muscle myosin heavy chain (MYH11), forming the oncogene CBFB-MYH11. The expressed protein, CBFβ-SMMHC, forms a heterodimer with the key hematopoietic transcription factor RUNX1. Although CBFβ-SMMHC was previously thought to dominantly repress RUNX1, recent work suggests that CBFβ-SMMHC functions together with RUNX1 to activate transcription of specific target genes. Targeting the activity of CBFβ-SMMHC is a promising approach for treating inv(16) AML, although currently there are no inhibitors of CBFβ-SMMHC ready for clinical use. An alternative approach is to indirectly target the fusion protein by inhibiting the activity of other proteins which are recruited to CBFβ-SMMHC and are required for its activity. One possible target is the epigenetic regulator histone deacetylase 1 (HDAC1), which was previously shown to colocalize with CBFβ-SMMHC on gene promoters. We hypothesized that HDAC1 was recruited to the CBFβ-SMMHC:RUNX1 complex and inhibitors of HDAC1 could be used to indirectly target its leukemogenic activity. In this study, we demonstrate that HDAC1 forms a complex with CBFβ-SMMHC, confirmed its colocalization with RUNX1 and CBFβ-SMMHC on the promoters of known fusion protein target genes, and determined that Hdac1 is required for expression of these genes. These results imply that HDAC1 is an important component of the CBFβ-SMMHC transcriptional complex, and that leukemia cells expressing the fusion protein may be sensitive to treatment with HDAC1 inhibitors. Both Hdac1 knockdown and treatment with the HDAC1 selective inhibitor entinostat in vitro results in a decrease in colony-forming ability and an increase in differentiation in CBFβ-SMMHC+ cells, implying that HDAC1 is required to maintain the differentiation block in the leukemia cells. Using a knock-in mouse model expressing CBFβ-SMMHC, we found that in vivo treatment with entinostat decreased leukemic burden and induced differentiation and apoptosis of leukemia cells. Importantly, entinostat treatment specifically targeted the leukemia cells with minimal toxicity to normal cells. We also tested the same treatment strategy on survival of the mice but found that leukemia cells were able to continue to grow after cessation of treatment. Overall, our results demonstrate the strict requirement for HDAC1 in CBFβ-SMMHC+ cells and reveal that it is a promising therapeutic target for treatment of inv(16) AML

Containing a firestorm: adaptive policies needed to address changing foreclosure landscape

Like a wildfire leaving devastation in its path, the foreclosure crisis continues to wreak havoc on many families and communities throughout the Fourth District, especially in the largest urban areas. Only a year ago the primary reason for foreclosures centered on subprime mortgages. Today, the primary driver is unemployment, further widening the consumption arc of this blaze.Foreclosure

HIV/STI Risk Factors Among African-American Students Attending Predominantly White Universities

Introduction: The majority of African American college students in the U.S. attend predominantly white institutions (PWIs). However, there is minimal research examining this population’s HIV/STI risk behaviors. The purpose of this investigation was to assess HIV/STI behavioral risk factors among African American college students (aged 18 – 24years) attending PWIs. (n = 2,568) Methods: Backwards step-wise logistic regression analyses were conducted to determine factors associated with a positive HIV/STI diagnosis (past year) among sexually active African American college students who participated in the Spring, 2006 National College Health Assessment. Findings: Nine factors were significantly associated with an HIV/STI diagnosis among African American college students attending PWIs. Different risk factors were associated with having a HIV/STI diagnosis among African American male and female college students. These results may be useful to HIV/STIs prevention programs targeting African American college students attending PWIs

Characterization of hydrothermal fluids that alter the upper oceanic crust to spilite and epidosite: Fluid inclusion evidence from the Semail (Oman) and Troodos (Cyprus) ophiolites

Pervasive alteration of basaltic oceanic crust by heated seawater at greenschist facies conditions produces two contrasting hydrothermal rocks. “Spilites”, consisting of chlorite + albite + quartz ± actinolite ± epidote, occur typically with regional extents. Locally spilites are metasomatically transformed to “epidosites” consisting of epidote + quartz + titanite + hematite or magnetite. Both alteration types have been proposed as markers of deep hydrothermal upflow in sub-seafloor convection cells, and as sources of the ore metals in basalt-hosted seafloor massive sulfide deposits. Little direct evidence is available for the chemical compositions of these fluids in their states deep in the upflow zones prior to their discharge at the seafloor. To better characterize them we have conducted a field, petrographic and fluid inclusion study of the lavas, sheeted dikes and plagiogranites in the Semail ophiolite, with supporting samples from the Troodos ophiolite. Our results show that both the spilite- and epidosite-forming fluids were single-phase aqueous liquids during the hydrothermal alteration. At some sites their salinity is 3.1–3.2 wt.% NaCleq, which we take to represent the chlorinity of Cenomanian seawater in the Semail realm. At other sites salinities are as low as 2.4 wt.% NaCleq or as high as 5.7 wt.% NaCleq, attributable to liquid–vapor separation and partial remixing deep in the crust along the dew curve of seawater, prior to ascent of the fluids to the sites of fluid inclusion trapping. Hypersaline brines, often accompanied by vapor, are restricted to plagiogranites in both the Semail and Troodos ophiolites and they represent magmatic–hydrothermal fluids that pre-date and are genetically unrelated to the spilite and epidosite alteration. The volcanostratigraphic locations of the samples constrain their maximum depths to 1470–3600 m below seafloor during alteration. The range of possible fluid trapping pressures for all samples is 31–68 MPa. Trapping temperatures vary between sites from 145 to 440 °C for spilite fluids and 255 to 435 °C for epidosite fluids. Quantitative analyses of 12 elements in individual fluid inclusions by LA-ICP-MS define the chemical characters of the two alteration fluids. The Br/Cl ratio in the spilite fluid is the same as in modern seawater and the other elements fit expectations from seawater–basalt experiments at elevated temperature. Accordingly, concentrations of Li, B, Na, Cl, K, Br and Sr in the spilite fluid match those in modern black-smoker vent fluids in basaltic crust. Exceptions are Ca and Fe, which are enriched in the spilite fluid. As these elements may precipitate below or at the seafloor prior to vent sampling, we conclude that the spilite fluids are plausible feeders of basalt-hosted black-smoker vents. The epidosite fluid has broadly similar elemental concentrations to the spilite fluid, but vastly lower Fe, reflecting the highly oxidized state of epidosites. This suggests that epidosite fluids are incapabable of forming basalt-hosted seafloor massive sulfide deposits

Environment, seasonality and hunting strategies as influences on Natufian food procurement:The faunal remains from Shubayqa 1

Analysis of the faunal assemblage from Shubayqa 1 allows detailed discussion of food procurement through the sequence of occupation spanning the Early and Late Natufian. The influence of climate, season of occupation and hunting techniques on the subsistence economy is discussed. It is argued that targeted prey varied throughout the year, with mass hunting methods providing a large proportion of the meat. In the Late Natufian a decrease in passage migrant birds is interpreted as evidence for gradual drying of the environment, or less reliable rainfall from year-to-year. Availability of resources varied between the two phases of occupation, which, despite preceding the Younger Dryas, suggests that environmental conditions were changing. However, subsistence strategies were easily amended to maintain a plentiful supply of food