Non-destructive, whole-plant phenotyping reveals dynamic changes in water use efficiency, photosynthesis, and rhizosphere acidification of sorghum accessions under osmotic stress.

Noninvasive phenotyping can quantify dynamic plant growth processes at higher temporal resolution than destructive phenotyping and can reveal phenomena that would be missed by end-point analysis alone. Additionally, whole-plant phenotyping can identify growth conditions that are optimal for both above- and below-ground tissues. However, noninvasive, whole-plant phenotyping approaches available today are generally expensive, complex, and non-modular. We developed a low-cost and versatile approach to noninvasively measure whole-plant physiology over time by growing plants in isolated hydroponic chambers. We demonstrate the versatility of our approach by measuring whole-plant biomass accumulation, water use, and water use efficiency every two days on unstressed and osmotically stressed sorghum accessions. We identified relationships between root zone acidification and photosynthesis on whole-plant water use efficiency over time. Our system can be implemented using cheap, basic components, requires no specific technical expertise, and should be suitable for any non-aquatic vascular plant species.

Arabidopsis thaliana RHAMNOSE 1 condensate formation drives UDP-rhamnose synthesis.

Rhamnose is an essential component of the plant cell wall and is synthesized from uridine diphosphate (UDP)-glucose by the RHAMNOSE1 (RHM1) enzyme. RHM1 localizes to biomolecular condensates in plants, but their identity, formation, and function remain elusive. Combining live imaging, genetics, and biochemical approaches in Arabidopsis and heterologous systems, we show that RHM1 alone is sufficient to form enzymatically active condensates, which we name rhamnosomes. Rhamnosome formation is required for UDP-rhamnose synthesis and organ development. Overall, our study demonstrates a novel role for biomolecular condensation in metabolism and organismal development, and provides further support for how organisms have harnessed this biophysical process to regulate small molecule metabolism.

Energetics of intercavity diffusion in a simple model of a low-density p-tert-butylcalix[4]arene crystal.

Potentials of mean force calculated for the diffusion of small guest molecules (CO(2) and CH(4)) between adjacent host cavities in the beta(0) p-tert-butylcalix[4]arene polymorph reveal sufficiently high barriers to diffusion to justify characterizing the lattice voids in this crystal as independent host cavities rather than as extended volumes. In addition, the calculated barrier heights are consistent with a "relay" model for gas diffusion in this ostensibly nonporous organic solid involving the lateral sliding of the host bilayers.

Molecular dynamics of host-guest complexes of small gas molecules with calix[4]arenes.

The unexpected sorption of gases by a low-density p-tert-butylcalix[4]arene crystal polymorph raises fundamental questions about differential gas transport and sequestration in the organic solid state. To gain insight into the processes underlying these observations, we have used molecular dynamics simulations, augmented with calculations of potentials of mean force, to investigate the stability of isolated host-guest complexes and the relationship between the dynamics of these complexes and the dynamics of a solvated host molecule. Thermal fluctuations of the calixarenes themselves are found to be consistent with proposed mechanisms for gas entry into the host cavities, while relative host-guest stabilities correlate well with experimental absorption-desorption isotherms in some cases (CO2 and CH4) but not in others (C2H2). In these isolated systems, stable complexes characteristically form when the attractive interactions of the guest with the ring of negative charge density on the inner surface of the host cavity are not disrupted by thermal motion. The experimentally observed efficient uptake of gases such as C2H2 by the host crystals suggests, however, that stabilization of host-guest complexes in some systems may derive from dynamical constraints imposed by the crystal lattice.

Organizational and environmental factors that affect worker health and safety and patient outcomes.

This article reviews organizational factors that influence the satisfaction, health, safety, and well-being of health care workers and ultimately, the satisfaction, safety, and quality of care for patients. The impact of the work environment on working conditions and the effects on health care workers and patients are also addressed. Studies focusing on worker health and safety concerns affected by the organization and the physical work environment provide evidence of direct positive and/or adverse effects on performance and suggest indirect effects on the quality of patient care. The strongest links between worker and patient outcomes are demonstrated in literature on nosocomial transmission of infections. Transmission of infections from worker to patient and from patient to patient via health care worker has been well documented in clinical studies. Literature on outbreaks of infectious diseases in health care settings has linked the physical environment with adverse patient and worker outcomes. An increasing number of studies are looking at the relationship between improvement in organizational factors and measurable and positive change in patient outcomes. Characteristics of selected magnet hospitals are reviewed as one model for improving patient and worker outcomes.