No abstract

No abstract

The reaction of Mn2(CO)10 with P(SiMe3)3 in coordinating solvents at T >/= 220 degrees C yields low polydispersity, highly crystalline MnP nanoparticles for the first time. The effect of dimensional limiting has resulted in the stabilization of a ferromagnetic ground state at low temperatures, rather than the metamagnetic state observed in bulk (microcrystalline) MnP. The synthetic methodology reported here is demonstrated to be general for a number of different metals and phosphine sources.

Phase-pure FeP nanoparticles have been synthesized by the reaction of iron(III) acetylacetonate with tris(trimethylsilyl)phosphine at temperatures of 240-320 °C using trioctylphosphine oxide as a solvent and dodecylamine (DA), myristic acid (MA), or hexylphosphonic acid (HPA) as additional capping groups (ligands). The DA-capped particles prepared at 260 °C have an average diameter of 4.65 ( 0.74 nm with FeP being the only observed crystalline phase. Elemental analyses indicate a high percentage yield of FeP (85%) and are consistent with 12% TOPO incorporation in the product. The addition of MA has results similar to those of the addition of DA, whereas addition of HPA seems to inhibit crystallite growth, resulting in very small (ca. 1 nm) or amorphous particles that are difficult to isolate. Magnetic susceptibility data on DA-capped FeP suggest that the moments within each particle are coupled antiferromagnetically, at least over a short range; however, there is no evidence of a Ne ´el transition, in contrast to bulk FeP. It is likely that the FeP particles produced by this route are too small (ca. 5 nm) relative to the magnetic cell (2.9 nm) for the onset of long-range helical antiferromagnetic order, even at low temperatures (5 K) and fields (0.010 T).

The goals of this study were to determine if a change in certain motives to eat highly palatable food, as measured by the Palatable Eating Motives Scale (PEMS), could predict a change in body mass index (BMI) over time, to assess the temporal stability of these motive scores, and to test the reliability of previously reported associations between eating tasty foods to cope and BMI. BMI, demographics, and scores on the PEMS and the Binge Eating Scale were obtained from 192 college students. Test–retest analysis was performed on the PEMS motives in groups varying in three gap times between tests. Regression analyses determined what PEMS motives predicted a change in BMI over two years. The results replicated previous findings that eating palatable food for Coping motives (e.g., to forget about problems, reduce negative feelings) is associated with BMI. Test–retest correlations revealed that motive scores, while somewhat stable, can change over time. Importantly, among overweight participants, a change in Coping scores predicted a change in BMI over 2 years, such that a 1-point change in Coping predicted a 1.76 change in BMI (equivalent to a 10.5 lb. change in body weight) independent of age, sex, ethnicity, and initial binge-eating status (Cohen's f2 effect size = 1.44). The large range in change of Coping scores suggests it is possible to decrease frequency of eating to cope by more than 1 scale point to achieve weight losses greater than 10 lbs. in young overweight adults, a group already at risk for rapid weight gain. Hence, treatments aimed specifically at reducing palatable food intake for coping reasons vs. for social, reward, or conformity reasons, should help achieve a healthier body weight and prevent obesity if this motive-type is identified prior to significant weight gain.