Relationships between Molecular Structural Order Parameters and Equilibrium Water Dynamics in Aqueous Mixtures.

Water's unique thermophysical properties and how it mediates aqueous interactions between solutes have long been interpreted in terms of its collective molecular structure. The seminal work of Errington and Debenedetti [Nature 2001, 409, 318-321] revealed a striking hierarchy of relationships among the thermodynamic, dynamic, and structural properties of water, motivating many efforts to understand (1) what measures of water structure are connected to different experimentally accessible macroscopic responses and (2) how many such structural metrics are adequate to describe the collective structural behavior of water. Diffusivity constitutes a particularly interesting experimentally accessible equilibrium property to investigate such relationships because advanced NMR techniques allow the measurement of bulk and local water dynamics in nanometer proximity to molecules and interfaces, suggesting the enticing possibility of measuring local diffusivities that report on water structure. Here, we apply statistical learning methods to discover persistent structure-dynamic correlations across a variety of simulated aqueous mixtures, from alcohol-water to polypeptoid-water systems. We investigate a variety of molecular water structure metrics and find that an unsupervised statistical learning algorithm (namely, sequential feature selection) identifies only two or three independent structural metrics that are sufficient to predict water self-diffusivity accurately. Surprisingly, the translational diffusivity of water across all mixed systems studied here is strongly correlated with a measure of tetrahedral order given by water's triplet angle distribution. We also identify a separate small number of structural metrics that well predict an important thermodynamic property, the excess chemical potential of an idealized methane-sized hydrophobe in water. Ultimately, we offer a Bayesian method of inferring water structure by using only structure-dynamics linear regression models with experimental Overhauser dynamic nuclear polarization (ODNP) measurements of water self-diffusivity. This study thus quantifies the relationships among several distinct structural order parameters in water and, through statistical learning, reveals the potential to leverage molecular structure to predict fundamental thermophysical properties. In turn, these findings suggest a framework for solving the inverse problem of inferring water's molecular structure using experimental measurements such as ODNP studies that probe local water properties.

The RSNA Pulmonary Embolism CT Dataset.

Supplemental material is available for this article.

Does trust play a role when it comes to donations? A comparison of Italian and US higher education institutions.

Higher education institutions (HEIs) have experienced severe cutbacks in funding over the past few years, with universities examining options for alternative funding streams, such as alumni funding. Identifying the factors influencing their alumni's intentions to invest in their alma mater can be of significant importance when establishing a sustainable revenue stream. Within this context, empirical research on the potential role of trust is scarce. This paper aims to deepen the analysis of the relationship between alumni trust and engagement as well as three outcomes, namely support, commitment, and attitude toward donation. A structural equation model was tested on two samples of US (n = 318) and Italian (n = 314) alumni. Although both countries are affluent and developed countries, the USA has an established tradition of alumni donations, which is not such a developed practice in Italy. For both countries, results confirm that engagement is an antecedent of trust, which in turn leads to the three investigated outcomes (support, commitment, and attitude toward donations). In contrast, the effect of commitment on attitude toward donations is significant only for the USA universities. The paper has interesting theoretical and managerial implications. From a theoretical point of view, the study aims to address a gap concerning the role of trust in the HE context. Managerially, the study has significant implications for universities that want to change alumni attitude toward donations.

Competing during a pandemic? Retailers' ups and downs during the COVID-19 outbreak.

The COVID-19 pandemic (that started in early 2020) is causing several disruptions in the short- and mid-term, to which businesses have to adapt. Some retailers have reacted to the emergency immediately, displaying a plethora of different intervention types. The authors aim to synthesize the challenges that retailers are facing during the COVID-19 emergency. We do this from the perspective of both consumers and managers, with the goal of providing guidelines on and examples of how retailers can handle this unprecedented situation.

Comparison of cervical esophagus dose-volumes for three radiotherapy techniques for head and neck cancer.

PURPOSE: This study compares the radiation dose-volume of the cervical esophagus during head and neck radiotherapy using three different techniques. METHODS: Treatment plans of 58 patients from 3/04 to 1/06 treated with bilateral head and neck radiotherapy were analyzed retrospectively. A comparison of the cervical esophagus dose with three-field 3D conformal RT (3DRT, n=34), whole-field IMRT (WF-IMRT, n=12), and half-beam IMRT (HB-IMRT, n=12) was performed. The volumes of esophagus receiving > or =50Gy (V50), > or =54Gy (V54) and > or = 60Gy (V60) and lengths receiving circumferential dose > or = 50Gy (L50) and > or = 54Gy (L54) were evaluated. RESULTS: Maximum dose, V54 and L54 were greater for the first 2cm and entire cervical esophagus with WF-IMRT than HB-IMRT or 3DRT. In patients requiring a high match, WF-IMRT was associated with a greater maximum dose, V54 and L54 than HB-IMRT and 3DRT (p<0.05). In the low match group, WF-IMRT was associated with a greater V54 and L54 (p<0.05). Low neck disease, low primary site, and definitive radiotherapy were associated with increased irradiation of the esophagus. CONCLUSION: Treatment of the lower neck with IMRT is associated with increased irradiation to the cervical esophagus, and dose constraints should be included to reduce toxicity.

A genomewide scan for early-onset coronary artery disease in 438 families: the GENECARD Study.

A family history of coronary artery disease (CAD), especially when the disease occurs at a young age, is a potent risk factor for CAD. DNA collection in families in which two or more siblings are affected at an early age allows identification of genetic factors for CAD by linkage analysis. We performed a genomewide scan in 1,168 individuals from 438 families, including 493 affected sibling pairs with documented onset of CAD before 51 years of age in men and before 56 years of age in women. We prospectively defined three phenotypic subsets of families: (1) acute coronary syndrome in two or more siblings; (2) absence of type 2 diabetes in all affected siblings; and (3) atherogenic dyslipidemia in any one sibling. Genotypes were analyzed for 395 microsatellite markers. Regions were defined as providing evidence for linkage if they provided parametric two-point LOD scores >1.5, together with nonparametric multipoint LOD scores >1.0. Regions on chromosomes 3q13 (multipoint LOD = 3.3; empirical P value <.001) and 5q31 (multipoint LOD = 1.4; empirical P value <.081) met these criteria in the entire data set, and regions on chromosomes 1q25, 3q13, 7p14, and 19p13 met these criteria in one or more of the subsets. Two regions, 3q13 and 1q25, met the criteria for genomewide significance. We have identified a region on chromosome 3q13 that is linked to early-onset CAD, as well as additional regions of interest that will require further analysis. These data provide initial areas of the human genome where further investigation may reveal susceptibility genes for early-onset CAD.