Health care providers (HCPs) are an important source of physical activity (PA) information. Two studies were conducted to qualitatively and quantitatively examine nurse practitioners'(NPs) and physician assistants' current PA counseling practices, knowledge and confidence to provide PA counseling and providers' perceptions about their current PA counseling practices. The specific aims for these two studies included quantitatively and qualitatively identifying the prevalence of PA counseling, perceived counseling knowledge and confidence, and educational training related to counseling. In study 1, survey respondents were currently practicing NPs and physician assistants. Participants completed a modified version of the Promotion of Physical Activity by Nurse Practitioners Questionnaire either online or in person during a population specific conference. The majority of both NP and physician assistant respondents reported routinely counseling patients about PA. There were no differences in perceived knowledge or confidence to provide PA counseling between the two populations. Approximately half of all respondents reported receiving training to provide PA counseling as part of their educational preparation for becoming a health practitioner. Nearly three-quarters of respondents reported interest in receiving additional PA counseling training. In study 2, five focus groups (FGs), stratified by practice type, were conducted with NPs and physician assistants. Both NPs and physician assistants reported discussing PA with their patients, particularly those with chronic illness. Participants reported that discussing lifestyle modifications with patients was the most common type of PA counseling provided. Increased confidence to counsel was associated with having PA knowledge and providing simple counseling, such as lifestyle modifications. Barriers to counseling included having more important things to discuss, lack of time during appointments, the current healthcare system, lack of reimbursement and perceived patient financial barriers. PA recommendation knowledge was highly variable, with few participants reporting specific guidelines. FG participants, while not familiar with the American College of Sports Medicines' "Exercise is Medicine" initiative indicated interest in its use and learning more about it. The findings of these two studies indicate that while NPs and physician assistants are knowledgeable, confident and currently providing some amount of PA counseling to patients, additional training in PA counseling is needed and desired.

X-ray free-electron lasers provide novel opportunities to conduct single particle analysis on nanoscale particles. Coherent diffractive imaging experiments were performed at the Linac Coherent Light Source (LCLS), SLAC National Laboratory, exposing single inorganic core-shell nanoparticles to femtosecond hard-X-ray pulses. Each facetted nanoparticle consisted of a crystalline gold core and a differently shaped palladium shell. Scattered intensities were observed up to about 7 nm resolution. Analysis of the scattering patterns revealed the size distribution of the samples, which is consistent with that obtained from direct real-space imaging by electron microscopy. Scattering patterns resulting from single particles were selected and compiled into a dataset which can be valuable for algorithm developments in single particle scattering research.

Single particle diffractive imaging data from Rice Dwarf Virus (RDV) were recorded using the Coherent X-ray Imaging (CXI) instrument at the Linac Coherent Light Source (LCLS). RDV was chosen as it is a well-characterized model system, useful for proof-of-principle experiments, system optimization and algorithm development. RDV, an icosahedral virus of about 70 nm in diameter, was aerosolized and injected into the approximately 0.1 μm diameter focused hard X-ray beam at the CXI instrument of LCLS. Diffraction patterns from RDV with signal to 5.9 Ångström were recorded. The diffraction data are available through the Coherent X-ray Imaging Data Bank (CXIDB) as a resource for algorithm development, the contents of which are described here.

The membrane proximal region (MPR, residues 649–683) and transmembrane domain (TMD, residues 684–705) of the gp41 subunit of HIV-1’s envelope protein are highly conserved and are important in viral mucosal transmission, virus attachment and membrane fusion with target cells. Several structures of the trimeric membrane proximal external region (residues 662–683) of MPR have been reported at the atomic level; however, the atomic structure of the TMD still remains unknown. To elucidate the structure of both MPR and TMD, we expressed the region spanning both domains, MPR-TM (residues 649–705), in Escherichia coli as a fusion protein with maltose binding protein (MBP). MPR-TM was initially fused to the C-terminus of MBP via a 42 aa-long linker containing a TEV protease recognition site (MBP-linker-MPR-TM).

Biophysical characterization indicated that the purified MBP-linker-MPR-TM protein was a monodisperse and stable candidate for crystallization. However, crystals of the MBP-linker-MPR-TM protein could not be obtained in extensive crystallization screens. It is possible that the 42 residue-long linker between MBP and MPR-TM was interfering with crystal formation. To test this hypothesis, the 42 residue-long linker was replaced with three alanine residues. The fusion protein, MBP-AAA-MPR-TM, was similarly purified and characterized. Significantly, both the MBP-linker-MPR-TM and MBP-AAA-MPR-TM proteins strongly interacted with broadly neutralizing monoclonal antibodies 2F5 and 4E10. With epitopes accessible to the broadly neutralizing antibodies, these MBP/MPR-TM recombinant proteins may be in immunologically relevant conformations that mimic a pre-hairpin intermediate of gp41.