Magneto-Optical Properties of Paramagnetic Superrotors.

We study the dynamics of paramagnetic molecular superrotors in an external magnetic field. An optical centrifuge is used to create dense ensembles of oxygen molecules in ultrahigh rotational states. In is shown, for the first time, that the gas of rotating molecules becomes optically birefringent in the presence of a magnetic field. The discovered effect of "magneto-rotational birefringence" indicates the preferential alignment of molecular axes along the field direction. We provide an intuitive qualitative model, in which the influence of the applied magnetic field on the molecular orientation is mediated by the spin-rotation coupling. This model is supported by the direct imaging of the distribution of molecular axes, the demonstration of the magnetic reversal of the rotational Raman signal, and by numerical calculations.

Atom-diatom scattering dynamics of spinning molecules.

We present full quantum mechanical scattering calculations using spinning molecules as target states for nuclear spin selective atom-diatom scattering of reactive D+H2 and F+H2 collisions. Molecules can be forced to rotate uni-directionally by chiral trains of short, non-resonant laser pulses, with different nuclear spin isomers rotating in opposite directions. The calculations we present are based on rotational wavepackets that can be created in this manner. As our simulations show, target molecules with opposite sense of rotation are predominantly scattered in opposite directions, opening routes for spatially and quantum state selective scattering of close chemical species. Moreover, two-dimensional state resolved differential cross sections reveal detailed information about the scattering mechanisms, which can be explained to a large degree by a classical vector model for scattering with spinning molecules.

Quantum resonances in selective rotational excitation of molecules with a sequence of ultrashort laser pulses.

We experimentally investigate the effect of quantum resonance in the rotational excitation of the simplest quantum rotor--a diatomic molecule. Using the techniques of high-resolution femtosecond pulse shaping and rotational state-resolved detection, we measure directly the amount of energy absorbed by molecules interacting with a periodic train of laser pulses, and study their dependence on the train period. We show that the energy transfer is significantly enhanced at quantum resonance, and use this effect to demonstrate selective rotational excitation of two nitrogen isotopologs, (14)N(2) and (15)N(2). Moreover, by tuning the period of the pulse train in the vicinity of a fractional quantum resonance, we achieve selective rotational excitation of para- and ortho-isomers of (15)N(2).

Nuclear spin selective laser control of rotational and torsional dynamics.

We explore the possibility of controlling rotational-torsional dynamics of non-rigid molecules with strong, non-resonant laser pulses and demonstrate that transient, laser-induced torsional alignment depends on the nuclear spin of the molecule. Consequently, nuclear spin isomers can be manipulated selectively by a sequence of time-delayed laser pulses. We show that two pulses with different polarization directions can induce either overall rotation or internal torsion, depending on the nuclear spin. Nuclear spin selective control of the angular momentum distribution may open new ways to separate and explore nuclear spin isomers of polyatomic molecules.

Control of molecular rotation with a chiral train of ultrashort pulses.

Trains of ultrashort laser pulses separated by the time of rotational revival (typically, tens of picoseconds) have been exploited for creating ensembles of aligned molecules. In this work we introduce a chiral pulse train--a sequence of linearly polarized pulses with the polarization direction rotating from pulse to pulse by a controllable angle. The chirality of such a train, expressed through the period and direction of its polarization rotation, is used as a new control parameter for achieving selectivity and directionality of laser-induced rotational excitation. The method employs chiral trains with a large number of pulses separated on the time scale much shorter than the rotational revival (a few hundred femtosecond), enabling the use of conventional pulse shapers.

Assisted living pilot program: background, methods, and facility characteristics.

Objectives. The Department of Veterans Affairs (VA) funded assisted living (AL), adult family home (AFH), and residential care for the first time in the Assisted Living Pilot Program (ALPP). This article describes the background and methods of the ALPP evaluation and the characteristics and experiences of the facilities. Method. Facility data were collected from the contracting/inspection process and a survey of ALPP facilities and those contacted but not participating in ALPP. Results. Data on 131 participating facilities are presented: 41 AFHs, 47 assisted living facilities (ALFs), and 43 residential care facilities (RCFs). The average facility had 33 beds (about one quarter Medicaid beds), for-profit ownership, and private rooms for ALPP residents, and about half had private baths. About two thirds of ALPP AFH providers spoke a primary language other than English. Discussion. Findings indicate that a wide range of community facilities were willing to provide care to residents with heterogeneous needs on VA funding.

Assisted living pilot program: utilization and cost findings.

Objective. The Department of Veterans Affairs funded assisted living, adult family home, and adult residential care for the first time in the Assisted Living Pilot Program (ALPP). This article compares the use and cost for individuals that entered ALPP and a comparison group. Method. This was a nonrandomized study. The comparison group consisted of VA patients who were eligible but did not enter an ALPP facility. The ALPP (n = 393) and comparison (n = 259) groups were followed for 12 months to assess ALPP facility, case management, and health care costs. Results. ALPP facility and ALPP case management costs were respectively $5,560 and $2,830 per individual. Total health care costs, including ALPP costs, were $11,533 higher for the ALPP group compared to the comparison group after adjusting for baseline differences. Discussion. Although ALPP successfully helped individuals transition to longer term care in these facilities, it was more costly than the comparison group.

Assisted living pilot program: health outcomes.

Objectives. Assisted living programs demonstrate variation in structure and services. The Department of Veterans Affairs funded this care for the first time in the Assisted Living Pilot Program (ALPP). This article presents resident health outcomes and the relationship between facility characteristics and outcomes. Method. This article presents results on 393 ALPP residents followed for 12 months after admission to 95 facilities. Results. A total of 19.8% residents died, and the average activities of daily living impairment did not change significantly. Half of the residents remained in an ALPP facility, with the average resident spending 315 days in the community during the 12-month follow-up period. This article found a limited number of characteristics of structure and staffing to be significantly associated with outcomes. Discussion. If differences among facility characteristics are not clearly related to differences in outcomes, then choices among type of setting can be based on the match of needs to available services, location, or preferences.

Histologic and immunohistochemical characterization of hemangiomas in the skin of seven young horses.

The histologic and immunochemical characteristics of benign vascular tumors excised from the skin of seven young horses were evaluated. The patients were male horses of various breeds and were 16 months of age or younger at the time of presentation. Six tumors occurred on the extremities, and one was removed from the lip. Histologically, most tumors consisted of cellular nodules of varying compactness with few to many blood-filled lumina. Nodular growth separated preexisting adnexa and subcutaneous collagen. Some tumors contained or consisted predominantly of loosely packed arrays of ramifying, veins, and capillaries separated by collagen within the dermis and subcutis. Within areas of nodular growth, multilayered vascular walls were encircled by reticulin strands that surrounded the endothelium and adjacent pericytes and also separated nonperivascular cells in the mass. Immunohistochemical staining of factor-VIII-related antigen and labeling by Ulex europeus-1 lectin was restricted to an innermost layer of cells surrounding vascular spaces, confirming their vascular endothelial origin. The plump fusiform cells arranged concentrically around the endothelium and some of those unassociated with vascular lumina stained with antibody to alpha-smooth muscle actin, as did the muscularis of larger vessels inside and outside of tumor nodules. These findings demonstrate an orderly arrangement between endothelium and supportive cells in these benign vascular neoplasms of young horses, similar to that observed during vascular development.

Development toxicity of fumonisin in Syrian hamsters.

The effects of fumonisin on development of Syrian hamster fetuses were studied using fumonisin B1 and B2 extracted from Fusarium moniliforme corn-culture and purified fumonisin B1. A significant increase in litters with fetal deaths occurred with the high doses of purified (18 mg FB1/kg) and culture-extracted (18 mg FB1 plus 4.5 mg FB2) fumonisin. It is concluded that prenatal exposure to fumonisin on days 8 and 9 of gestation is detrimental to fetal hamster survivability but does not induce clinical maternal intoxication at these doses. Equivalent doses of fumonisin B1, whether from culture-extract or pure solution produced similar results.

Developmental toxicity in hamsters of an aqueous extract of Fusarium moniliforme culture material containing known quantities of fumonisin B1.

The purpose of this study was to investigate potential detrimental effects of fumonisin B1 on the developing hamster. In experiments 1 and 2, timed-bred hamsters were dosed with 0.0 to 12.0 mg fumonisin B1/kg from day 8 to day 10 or day 12 of gestation. Clinical signs of material toxicity were not observed. Pregnant animals had reduced weight gains and lower total bilirubin levels than nonpregnant females. Hamsters were euthanized on day 15 of gestation. Histologic evaluation revealed autolytic placental changes expected in terminal gestation, as well as more advanced placental necrosis in association with fetal resorptions. Mean fetal weights and crown-rump lengths of living term fetuses on a per-litter basis did not differ between untreated controls and treated animals given 6.0 mg fumonisin B1/kg or less. However, at higher doses of fumonisin B1, there was an increased incidence of prenatal losses (deaths and resorptions). A greater percentage of litters had 1 or more fetuses affected, and a greater percentage of total fetuses were lost/litter as the fumonisin dosage increased. At 12.0 mg/kg, all litters were affected and 100% of the fetuses were dead and resorbing. Fumonisin B1 appears a developmental toxicant in hamsters. Toxicity is manifest by increased numbers of prenatal deaths and resorptions at doses that do not induce clinicopathologic evidence of maternal toxicity.