MRI: ID-Development of a Hybrid Scanning Fluorescence and Sum Frequency Spectroscopy Imaging Microscope

With this award from the Major Research Instrumentation program (MRI), Michael Mason and colleagues from the Department of Chemistry at the University of Maine will develop a hybrid scanning fluorescence (FL) and sum frequency (SF) spectroscopy imaging microscope. The instrument will be constructed by the addition of sample scanning and FL capability to an existing broadband SF spectrometer. The SF NIR pump source will be used to excite SF at the sample interface, while a modulated Argon ion CW laser will excite FL. These collinear sources will give rise to spatially and temporally correlated SF and FL signals which will be separated and individually detected. The instrument will simultaneously measure the fluorescence and sum frequency to yield information about the localized dynamics of a single particle, i.e. protein, and spatially correlated structural information about the bulk material containing the particle. This yields information about the interaction between the particle and the bulk not accessible by any other method. The proposal will initially investigate test projects including the study of membrane domain structure and membrane-membrane interactions, e,g., correlation of the structure and dynamics of lipid and protein molecules within planar supported lipid bilayers. Successful development of this instrument could lead to major breakthroughs in several fields ranging from surface chemistry and biophysics to nanotechnology and cellular biology

Existence of temperature on the nanoscale

We consider a regular chain of quantum particles with nearest neighbour interactions in a canonical state with temperature $T$. We analyse the conditions under which the state factors into a product of canonical density matrices with respect to groups of $n$ particles each and under which these groups have the same temperature $T$. In quantum mechanics the minimum group size $n_{min}$ depends on the temperature $T$, contrary to the classical case. We apply our analysis to a harmonic chain and find that $n_{min} = const.$ for temperatures above the Debye temperature and $n_{min} \propto T^{-3}$ below.Comment: Version that appeared in PR

Rural Superintendents as Political Agents: Grassroots Advocacy in Appalachian Districts of Southeast Ohio

This qualitative inquiry explores the narratives of rural superintendents regarding their roles as moral agents in the politics of public school settings and how they view their moral and political advocacy as grassroots activism for student and community rights. Insights from superintendent narratives provided themes about the history, practice, and expectations of school leaders as political agents within their respective communities. These themes focused on activism and advocacy for equitable funding and policymaking that specifically related to transportation, testing, and technology. Findings describe and define how superintendents make meaning of their political and public obligations and provide data that can help leadership preparation programs better prepare candidates for meaningful political practice

MRI: Acquisition of a SQUID Magnetometer for Analysis of Advanced Materials

Technical Summary: Superconducting quantum interference device (SQUID) magnetometry is a non-destructive technique that reveals detailed information about the electron spin interactions in many types of materials. This project will involve a state-of-the-art SQUID magnetometer and Magnetic Property Measurement System (MPMS), which is a critical tool for characterizing several types of materials currently being investigated by researchers within the Laboratory for Surface Science & Technology (LASST) and other University of Maine (UMaine) laboratories. Specific measurement capabilities include DC and AC magnetic susceptibility, magnetoresistivity, van der Paaw conductivity, and Hall mobility. State-of-the-art MPMS capabilities will be especially valuable to several research programs at UMaine pertaining to (i) surface magnetism in nanoparticles, (ii) magnetic anisotropies in sedimentary rocks, (iii) electrical transport in physical and chemical sensing devices, (iv) optical properties of nanostructures in high magnetic fields, and (v) magnetic nanoparticle based biosensors. The MPMS will serve as a focal point for training undergraduates, graduate students, postdocs, and visiting scientists in magnetic materials, nanotechnology, biophysics, and materials science. This instrument is a critical tool for expanding the capacity of UMaine research into magnetic aspects of nanotechnology, biophysics, sensor technology, and materials science. As no SQUID magnetometer currently exists in the State of Maine, the instrumentation will provide access for research projects from interested parties throughout the state, including non-Ph.D. granting institutions and small Maine businesses. The instrument is relatively easy to operate and provides direct information on electron spin interactions, and thus it will be a powerful tool to teach physics and nanotechnology concepts to several different constituents participating in UMaine outreach activities, including K-12 students and teachers, the general public, under-represented groups, and industry partners.Layman Summary: Superconducting quantum interference device (SQUID) magnetometry is a non-destructive technique that reveals detailed information about the electron spin interactions in many types of materials. Knowledge of electron interactions in materials is extremely important in building the next generation of computers, electronics, and contrast agents in biological magnetic screening techniques (i.e. MRI). To gain the necessary information, a system with control over both the magnetic field strength and temperature is critical. To this end, a SQUID/Magnetic Property Measurement System (MPMS) is ideal for these measurements. This project will purchase a state-of-the-art MPMS system and will be especially valuable to several research programs at UMaine pertaining to surface magnetism in nanoparticles, magnetic anisotropies in sedimentary rocks, electrical transport in physical and chemical sensing devices, and magnetic nanoparticle based biosensors. The proposed MPMS will serve as a focal point for training undergraduates, graduate students, postdocs, and visiting scientists in magnetic materials, nanotechnology, biophysics, and materials science. As no SQUID magnetometer currently exists in the State of Maine, the instrumentation will provide access for research projects from interested parties throughout the state, including non-Ph.D. granting institutions and small Maine businesses. The instrument is relatively easy to operate and provides direct information on electron spin interactions, and thus it will be a powerful tool to teach physics and nanotechnology concepts to several different constituents participating in UMaine outreach activities, including K-12 students and teachers, the general public, under-represented groups, and industry partners

Local Versus Global Thermal States: Correlations and the Existence of Local Temperatures

We consider a quantum system consisting of a regular chain of elementary subsystems with nearest neighbor interactions and assume that the total system is in a canonical state with temperature $T$. We analyze under what condition the state factors into a product of canonical density matrices with respect to groups of $n$ subsystems each, and when these groups have the same temperature $T$. While in classical mechanics the validity of this procedure only depends on the size of the groups $n$, in quantum mechanics the minimum group size $n_{min}$ also depends on the temperature $T$! As examples, we apply our analysis to a harmonic chain and different types of Ising spin chains. We discuss various features that show up due to the characteristics of the models considered. For the harmonic chain, which successfully describes thermal properties of insulating solids, our approach gives a first quantitative estimate of the minimal length scale on which temperature can exist: This length scale is found to be constant for temperatures above the Debye temperature and proportional to $T^{-3}$ below.Comment: 12 pages, 5 figures, discussion of results extended, accepted for publication in Phys. Rev.

Designer Reagents for Mass Spectrometry-Based Proteomics: Clickable Cross-Linkers for Elucidation of Protein Structures and Interactions

We present novel homobifunctional amine-reactive clickable cross-linkers (CXLs) for investigation of three-dimensional protein structures and protein–protein interactions (PPIs). CXLs afford consolidated advantages not previously available in a simple cross-linker, including (1) their small size and cationic nature at physiological pH, resulting in good water solubility and cell-permeability, (2) an alkyne group for bio-orthogonal conjugation to affinity tags via the click reaction for enrichment of cross-linked peptides, (3) a nucleophilic displacement reaction involving the 1,2,3-triazole ring formed in the click reaction, yielding a lock-mass reporter ion for only clicked peptides, and (4) higher charge states of cross-linked peptides in the gas-phase for augmented electron transfer dissociation (ETD) yields. Ubiquitin, a lysine-abundant protein, is used as a model system to demonstrate structural studies using CXLs. To validate the sensitivity of our approach, biotin-azide labeling and subsequent enrichment of cross-linked peptides are performed for cross-linked ubiquitin digests mixed with yeast cell lysates. Cross-linked peptides are detected and identified by collision induced dissociation (CID) and ETD with linear quadrupole ion trap (LTQ)-Fourier transform ion cyclotron resonance (FTICR) and LTQ-Orbitrap mass spectrometers. The application of CXLs to more complex systems (e.g., in vivo cross-linking) is illustrated by Western blot detection of Cul1 complexes including known binders, Cand1 and Skp2, in HEK 293 cells, confirming good water solubility and cell-permeability

What is the effect of a decision aid in potentially vulnerable parents? Insights from the head CT choice randomized trial.

ObjectiveTo test the hypotheses that use of the Head CT Choice decision aid would be similarly effective in all parent/patient dyads but parents with high (vs low) numeracy experience a greater increase in knowledge while those with low (vs high) health literacy experience a greater increase in trust.MethodsThis was a secondary analysis of a cluster randomized trial conducted at seven sites. One hundred seventy-two clinicians caring for 971 children at intermediate risk for clinically important traumatic brain injuries were randomized to shared decision making facilitated by the DA (n = 493) or to usual care (n = 478). We assessed for subgroup effects based on patient and parent characteristics, including socioeconomic status (health literacy, numeracy and income). We tested for interactions using regression models with indicators for arm assignment and study site.ResultsThe decision aid did not increase knowledge more in parents with high numeracy (P for interaction [Pint ] = 0.14) or physician trust more in parents with low health literacy (Pint  = 0.34). The decision aid decreased decisional conflict more in non-white parents (decisional conflict scale, -8.14, 95% CI: -12.33 to -3.95; Pint  = 0.05) and increased physician trust more in socioeconomically disadvantaged parents (trust in physician scale, OR: 8.59, 95% CI: 2.35-14.83; Pint  = 0.04).ConclusionsUse of the Head CT Choice decision aid resulted in less decisional conflict in non-white parents and greater physician trust in socioeconomically disadvantaged parents. Decision aids may be particularly effective in potentially vulnerable parents

Angiofil®-mediated visualization of the vascular system by microcomputed tomography: a feasibility study

Visualization of the vascular systems of organs or of small animals is important for an assessment of basic physiological conditions, especially in studies that involve genetically manipulated mice. For a detailed morphological analysis of the vascular tree, it is necessary to demonstrate the system in its entirety. In this study, we present a new lipophilic contrast agent, Angiofil®, for performing postmortem microangiography by using microcomputed tomography. The new contrast agent was tested in 10 wild-type mice. Imaging of the vascular system revealed vessels down to the caliber of capillaries, and the digital three-dimensional data obtained from the scans allowed for virtual cutting, amplification, and scaling without destroying the sample. By use of computer software, parameters such as vessel length and caliber could be quantified and remapped by color coding onto the surface of the vascular system. The liquid Angiofil® is easy to handle and highly radio-opaque. Because of its lipophilic abilities, it is retained intravascularly, hence it facilitates virtual vessel segmentation, and yields an enduring signal which is advantageous during repetitive investigations, or if samples need to be transported from the site of preparation to the place of actual analysis, respectively. These characteristics make Angiofil® a promising novel contrast agent; when combined with microcomputed tomography, it has the potential to turn into a powerful method for rapid vascular phenotyping

Applying Phenomenography to Develop a Comprehensive Understanding of Ethics in Engineering Practice

This Work-in-Progress Research paper describes (1) the contemporary research space on ethics education in engineering; (2) our long-term research plan; (3) the theoretical underpinnings of Phase 1 of our research plan (phenomenography); and (4) the design and developmental process of a phenomenographic interview protocol to explore engineers' experiences with ethics. Ethical behavior is a complex phenomenon that is complicated by the institutional and cultural contexts in which it occurs. Engineers also have varied roles and often work in a myriad of capacities that influence their experiences with and understanding of ethics in practice. We are using phenomenography, a qualitative research approach, to explore and categorize the ways engineers experience and understand ethical engineering practice. Specifically, phenomenography will allow us to systematically investigate the range and complexity of ways that engineers experience ethics in professional practice in the health products industry. Phenomenographic data will be obtained through a specialized type of semi-structured interview. Here we introduce the design of our interview protocol and its four sections: Background, Experience, Conceptual, and Summative. We also describe our iterative process for framing questions throughout each section

Dermanyssus gallinae in layer farms in Kosovo: a high risk for salmonella prevalence

Background The poultry red mite (PRM), Dermanyssus gallinae (D.g.) is a serious ectoparasitic pest of poultry and potential pathogen vector. The prevalence of D. g. and the prevalence of Salmonella spp. within mites on infested laying poultry farms were investigated in Kosovo. Findings In total, 14 populated layer farms located in the Southern Kosovo were assessed for D. g. presence. Another two farms in this region were investigated 6 months after depopulation. Investigated flocks were all maintained in cages, a common housing system in Kosovo. A total of eight farms were found to be infested with D. g. (50%) at varying levels, including the two depopulated farms. The detection of Salmonella spp. from D. g. was carried out using PCR. Out of the eight layer farms infested with D. g., Salmonella spp. was present in mites on three farms (37.5%). Conclusions This study confirms the high prevalence of D. g. in layer flocks in Kosovo and demonstrates the link between this mite and the presence of Salmonella spp. on infested farms