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Two-photon-induced fluorescence is observed from the photodynamic phycobiliprotein phycoerythrin. Temporal, spectral, and intensity-dependent properties of the two-photon-induced fluorescence emission from phycoerythrin excited by a 1.06-mum laser beam are reported. The measured two-photon absorption cross section of phycoerythrin is an order of magnitude larger than that of Rhodamine 6G. The potential applications of phycobiliproteins for two-photon-induced fluorescence for microscopy of three-dimensional biological samples and three-dimensional optical memory are discussed.

Light transducing phycobiliproteins are encapsulated in optically transparent sol-gel matrices. Absorption and fluorescence spectroscopies are used to characterize the effect of the sol-gel encapsulation on the conformation and aggregation states of the three major phycobiliproteins present in phycobilisomes: phycoerythrin, phycocyanin, and allophycocyanin. It is found that the effects of sol-gel entrapment on the spectroscopic properties are significantly different for the three phycobiliproteins. The results indicate that phycoerythrin undergoes only minor change in its native structure when entrapped in sol-gel. However, significant changes in conformation and aggregation state occur when phycocyanin and allophycocyanin are entrapped in sol-gel matrices. A thin film of sol-gel encapsulated phycoerythrin is also coated on an optical fiber surface and strong fluorescence from the evanescent wave excitation is detected. The potential applications of sol-gel encapsulated phycobiliproteins in biosensors are discussed. © 1996 Kluwer Academic Publishers.

Women represent the majority of medical students in several countries. In any surgical specialty and above all in surgical leadership positions, women still remain disproportionally underrepresented. The objective of this study was to investigate female surgeons’ career advancement and satisfaction with training. A standardized questionnaire was devised and sent out via the web-based survey tool SurveyMonkey® to female surgeons in the German federal state of North Rhine-Westphalia. A total of 125 completed questionnaires were analyzed (response rate 40.8%). Female surgeons are at least largely (76%) satisfied with their surgical training. Increased time (>5 h/week) as the principal surgeon in the operating room significantly stimulates the satisfaction with the surgical training (86% vs. 68%, p = 0.0384). At the participants’ current workplace, the heads of departments are predominantly male surgeons (91%). Respondents not satisfied with their surgical training prefer a female head of department more frequently (24% vs. 2%, p = 0.0085). The majority of the respondents themselves aspire to become a consultant surgeon (56%), while only 12% intend to become a head of a department. Female surgeons aiming at leadership positions work overtime (≥50 h/week) significantly more frequently (81% vs. 57%, p = 0.0041). Favoritism of male colleagues is perceived by 34%. Respondents who do not perceive any preferential treatment are significantly more satisfied with their surgical training (88% vs. 57%, p = 0.0004). In conclusion, female surgeons seem positive about their career choice, once in the surgical profession, and aptly fill upcoming positions. Women interested in surgery are likely to pursue a surgical career despite the alleged workload, demonstrating the importance of professional self-fulfillment among female surgeons.

Background: Experiential learning activities on care for people with disabilities (PWD) would help nursing students develop the knowledge, skills, and attitudes (KSAs) needed to provide quality care for PWD., Purpose: The purpose of this study was to evaluate the perceived changes in nursing students' KSAs related to the care for PWD following participation in health assessment and prevention (HAP) experiential learning activities., Methods: This was a quasi-experimental, pre- and posttest educational intervention study. Nursing students (n = 160) attended multiple experiential learning activities as a required part of their HAP coursework and completed a pre and posttest survey to assess changes in their KSAs., Results: Participation in experiential learning activities on care for PWD was associated with significant increases in perceived knowledge, skills and positive attitudes toward PWD., Conclusions: Experiential learning activities aligned with core competencies for health care providers caring for PWDs have the potential to change nursing care and address health inequities for this population., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Charge transport in biomolecules is crucial for many biological and technological applications, including biomolecular electronics devices and biosensors. RNA has become the focus of research because of its importance in biomedicine, but its charge transport properties are not well understood. Here, we use the Scanning Tunneling Microscopy-assisted molecular break junction method to measure the electrical conductance of particular 5-base and 10-base single-stranded (ss) RNA sequences capable of base stacking. These ssRNA sequences show single-molecule conductance values around [Formula: see text] ([Formula: see text]), while equivalent-length ssDNAs result in featureless conductance histograms. Circular dichroism (CD) spectra and MD simulations reveal the existence of extended ssRNA conformations versus folded ssDNA conformations, consistent with their different electrical behaviors. Computational molecular modeling and Machine Learning-assisted interpretation of CD data helped us to disentangle the structural and electronic factors underlying CT, thus explaining the observed electrical behavior differences. RNA with a measurable conductance corresponds to sequences with overall extended base-stacking stabilized conformations characterized by lower HOMO energy levels delocalized over a base-stacking mediating CT pathway. In contrast, DNA and a control RNA sequence without significant base-stacking tend to form closed structures and thus are incapable of efficient CT., (© 2023. The Author(s).)

Biological particles have evolved to possess mechanical characteristics necessary to carry out their functions. We developed a computational approach to "fatigue testing in silico", in which constant-amplitude cyclic loading is applied to a particle to explore its mechanobiology. We used this approach to describe dynamic evolution of nanomaterial properties and low-cycle fatigue in the thin spherical encapsulin shell, thick spherical Cowpea Chlorotic Mottle Virus (CCMV) capsid, and thick cylindrical microtubule (MT) fragment over 20 cycles of deformation. Changing structures and force-deformation curves enabled us to describe their damage-dependent biomechanics (strength, deformability, stiffness), thermodynamics (released and dissipated energies, enthalpy, and entropy) and material properties (toughness). Thick CCMV and MT particles experience material fatigue due to slow recovery and damage accumulation over 3-5 loading cycles; thin encapsulin shells show little fatigue due to rapid remodeling and limited damage. The results obtained challenge the existing paradigm: damage in biological particles is partially reversible owing to particle's partial recovery; fatigue crack may or may not grow with each loading cycle and may heal; and particles adapt to deformation amplitude and frequency to minimize the energy dissipated. Using crack size to quantitate damage is problematic as several cracks might form simultaneously in a particle. Dynamic evolution of strength, deformability, and stiffness, can be predicted by analyzing the cycle number (N) dependent damage, [Formula: see text] , where α is a power law and N f is fatigue life. Fatigue testing in silico can now be used to explore damage-induced changes in the material properties of other biological particles. STATEMENT OF SIGNIFICANCE: Biological particles possess mechanical characteristics necessary to perform their functions. We developed "fatigue testing in silico" approach, which employes Langevin Dynamics simulations of constant-amplitude cyclic loading of nanoscale biological particles, to explore dynamic evolution of the mechanical, energetic, and material properties of the thin and thick spherical particles of encapsulin and Cowpea Chlorotic Mottle Virus, and the microtubule filament fragment. Our study of damage growth and fatigue development challenge the existing paradigm. Damage in biological particles is partially reversible as fatigue crack might heal with each loading cycle. Particles adapt to deformation amplitude and frequency to minimize energy dissipation. The evolution of strength, deformability, and stiffness, can be accurately predicted by analyzing the damage growth in particle structure., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

We investigated costs of delivering the Tailored Activity Program (TAP) and cost savings from two perspectives (health sector and societal) for people living with dementia (PLWD) and their caregivers (dyads) compared to attention control (AC) using data from a randomized controlled trial. The evaluation assessed intervention delivery costs and caregiver reported health care utilization. The total intervention cost of TAP was $1707/dyad versus $864/dyad for AC, and total costs over 6 months for TAP dyads as compared to AC were $1299 (CI: -$10,496, $7898) less from the healthcare perspective, and $761 (CI: -$10,133, $8611) less from the societal perspective. TAP cost savings are driven by lower use of healthcare services among participating dyads, but further analyses with larger samples is warranted to confirm its financial impact.

The search-and-capture model of spindle assembly has been a guiding principle for understanding prometaphase for decades. The computational model presented allows one to address two questions: how rapidly the microtubule-kinetochore connections are made, and how accurate these connections are. In most previous numerical simulations, the model geometry was drastically simplified. Using the CellDynaMo computational platform, we previously introduced a geometrically and mechanically realistic 3D model of the prometaphase mitotic spindle, and used it to evaluate thermal noise and microtubule kinetics effects on the capture of a single chromosome. Here, we systematically investigate how geometry and mechanics affect a spindle assembly's speed and accuracy, including nuanced distinctions between merotelic , mero-amphitelic , and mero-syntelic chromosomes. We find that softening of the centromere spring improves accuracy for short chromosome arms, but accuracy disappears for long chromosome arms. Initial proximity of chromosomes to one spindle pole makes assembly accuracy worse, while initial chromosome orientation matters less. Chromokinesins, added onto flexible chromosome arms, allow modeling of the polar ejection force, improving a spindle assembly's accuracy for a single chromosome. However, spindle space crowding by multiple chromosomes worsens assembly accuracy. Our simulations suggest that the complex microtubule network of the early spindle is key to rapid and accurate assembly.

Although Hispanic/Latino older adults are at disproportionate and increased risk for Alzheimer's disease and related dementias, few evidence-based supportive care interventions are specifically developed for or adapted for this population. Adapting a supportive care intervention requires more than Spanish language translation; it necessitates an understanding of cultural nuances and care preferences of Hispanic/Latino families and staff who implement the intervention. This article describes the cultural adaptation of the Adult Day Service Plus intervention for delivery by staff to Hispanic/Latino caregivers, which was guided by the cultural adaptation process model. Also, using the Framework for Reporting Adaptations and Modifications-Enhanced, we discuss (a) when modifications were made, (b) who determined the modifications needed, (c) what aspects of the intervention were modified, (d) the relationship to fidelity and how fidelity was maintained, and (e) reasons for modifications. Modifications to the delivery and content were changed to reflect the values and norms of both the Hispanic/Latino staff and the caregivers they serve. As supportive interventions for caregivers are developed and implemented into real-world settings, inclusion of cultural elements may enhance research participation among Hispanic/Latino provider sites, people living with dementia, and their caregivers. Cultural adaptation is an essential consideration when developing, adapting, and implementing previously tested evidence-based interventions. Cultural adaptation offers an important lens by which to identify contextual factors that influence successful adoption to assure equity in the reach of evidence-based programs., (© The Author(s) 2022. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Elucidating the structure-function relationships for therapeutic RNA mimicking phosphorodiamidate morpholino oligonucleotides (PMOs) is challenging due to the lack of information about their structures. While PMOs have been approved by the US Food and Drug Administration for treatment of Duchenne muscular dystrophy, no structural information on these unique, charge-neutral, and stable molecules is available. We performed circular dichroism and solution viscosity measurements combined with molecular dynamics simulations and machine learning to resolve solution structures of 22-mer, 25-mer, and 30-mer length PMOs. The PMO conformational dynamics are defined by the competition between non-polar nucleobases and uncharged phosphorodiamidate groups for shielding from solvent exposure. PMO molecules form non-canonical, partially helical, stable folded structures with a small 1.4- to 1.7-nm radius of gyration, low count of three to six base pairs and six to nine base stacks, characterized by -34 to -51 kcal/mol free energy, -57 to -103 kcal/mol enthalpy, and -23 to -53 kcal/mol entropy for folding. The 4.5- to 6.2-cm 3 /g intrinsic viscosity and Huggins constant of 4.5-9.9 are indicative of extended and aggregating systems. The results obtained highlight the importance of the conformational ensemble view of PMO solution structures, thermodynamic stability of their non-canonical structures, and concentration-dependent viscosity properties. These principles form a paradigm to understand the structure-properties-function relationship for therapeutic PMOs to advance the design of new RNA-mimic-based drugs., Competing Interests: D.P. and A.C. are employees of Sarepta Therapeutics Inc. and may own stock/options in the company., (© 2023 The Author(s).)

Background: Despite recommendations to include disability content in nursing education, nursing students have little exposure to disability education, which would help to develop necessary knowledge, skills, and attitudes in learning to care for patients with disabilities., Purpose: This study evaluated learners' perceptions of the effectiveness of a tabletop simulation in meeting their learning needs related to nursing care for children with disabilities and their families., Methods: The research design was a descriptive educational intervention study. Nursing students (n = 234) enrolled in the pediatric nursing course attended the simulation as a required part of their coursework., Results: The majority of the students found the tabletop simulation with disability content to be an effective educational intervention., Conclusions: The results obtained from this study indicated that the tabletop simulation was an effective educational strategy for nursing students' learning to provide care for children with disabilities and their families., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Morbidity and mortality from COVID-19 have unduly affected older adults from racial and ethnic minority groups. In this article, we highlight the experiences and vulnerabilities of diverse older adults with complex health and social needs when their access to vital, but overlooked, community-based adult day service centers (ADSCs) was abruptly cut off during a pandemic. Pandemic-related ADSC closures left vulnerable older adults and their care partners without essential daily support and services, such as health monitoring and socialization. However, the magnitude of the impact of ADSC closures on well-being, particularly among members of racial/ethnic minority groups, has yet to be measured with any form of "big data" because large-scale, nationally representative data sets consisting of participant-level information and outcomes associated with ADSC participation do not yet exist. Unmet needs of older adults resulting from pandemic-related ADSC closures are underrecognized because of a lack of systematic data collection, undermining efforts to achieve health equity. We call on ADSCs to link rigorous collection of racial and ethnic data to quality measures of access to equitable "age-friendly" care as a means of better supporting diverse community-dwelling older adults beyond the COVID-19 pandemic. ( Am J Public Health . 2022;112(10):1421-1428. https://doi.org/10.2105/AJPH.2022.306968).

Minoritized older adults face multiple health inequities and disparities, but are less likely to benefit from evidence-based health care interventions. With the increasing diversity of the U.S. aging population, there is a great promise for gerontology researchers to partner with racial/ethnic minority organizations and underrepresented communities to develop and implement evidence-based health interventions. Community-Based Participatory Research and Implementation Science offer guidance and strategies for researchers to develop and sustain community partnerships. However, researchers partnering with community organizations continue to face challenges in these collaborations, study outcomes, and sustainability. This may be especially true for those junior in their career trajectory or new to community-engaged research. The purpose of this forum article is to detail critical challenges that can affect gerontology researcher-community partnerships and relationships from the perspective of researchers. Seven challenges (pre- or mid-intervention design, implementation, and postimplementation phases) described within the Equity-focused Implementation Research for health programs framework are identified and discussed. Potential solutions are also presented. Planning for potential obstacles of the researcher-community partnerships can inform innovative solutions that will facilitate successful partnerships, thereby promoting the advancement of collaborative research between academic institutions and community organizations to improve older adult health outcomes., (© The Author(s) 2021. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

We introduce a Stochastic Reaction-Diffusion-Dynamics Model (SRDDM) for simulations of cellular mechanochemical processes with high spatial and temporal resolution. The SRDDM is mapped into the CellDynaMo package, which couples the spatially inhomogeneous reaction-diffusion master equation to account for biochemical reactions and molecular transport within the Langevin Dynamics (LD) framework to describe dynamic mechanical processes. This computational infrastructure allows the simulation of hours of molecular machine dynamics in reasonable wall-clock time. We apply SRDDM to test performance of the Search-and-Capture of mitotic spindle assembly by simulating, in three spatial dimensions, dynamic instability of elastic microtubules anchored in two centrosomes, movement and deformations of geometrically realistic centromeres with flexible kinetochores and chromosome arms. Furthermore, the SRDDM describes the mechanics and kinetics of Ndc80 linkers mediating transient attachments of microtubules to the chromosomal kinetochores. The rates of these attachments and detachments depend upon phosphorylation states of the Ndc80 linkers, which are regulated in the model by explicitly accounting for the reactions of Aurora A and B kinase enzymes undergoing restricted diffusion. We find that there is an optimal rate of microtubule-kinetochore detachments which maximizes the accuracy of the chromosome connections, that adding chromosome arms to kinetochores improve the accuracy by slowing down chromosome movements, that Aurora A and kinetochore deformations have a small positive effect on the attachment accuracy, and that thermal fluctuations of the microtubules increase the rates of kinetochore capture and also improve the accuracy of spindle assembly., Competing Interests: The authors have declared that no competing interests exist.

Microtubules (MTs), a cellular structure element, exhibit dynamic instability and can switch stochastically from growth to shortening; but the factors that trigger these processes at the molecular level are not understood. We developed a 3D Microtubule Assembly and Disassembly DYnamics (MADDY) model, based upon a bead- per -monomer representation of the αβ-tubulin dimers forming an MT lattice, stabilized by the lateral and longitudinal interactions between tubulin subunits. The model was parameterized against the experimental rates of MT growth and shortening, and pushing forces on the Dam1 protein complex due to protofilaments splaying out. Using the MADDY model, we carried out GPU-accelerated Langevin simulations to access dynamic instability behavior. By applying Machine Learning techniques, we identified the MT characteristics that distinguish simultaneously all four kinetic states: growth, catastrophe, shortening, and rescue. At the cellular 25 μM tubulin concentration, the most important quantities are the MT length L , average longitudinal curvature κ long , MT tip width w , total energy of longitudinal interactions in MT lattice U long , and the energies of longitudinal and lateral interactions required to complete MT to full cylinder U long add and U lat add . At high 250 μM tubulin concentration, the most important characteristics are L , κ long , number of hydrolyzed αβ-tubulin dimers n hyd and number of lateral interactions per helical pitch n lat in MT lattice, energy of lateral interactions in MT lattice U lat , and energy of longitudinal interactions in MT tip u long . These results allow greater insights into what brings about kinetic state stability and the transitions between states involved in MT dynamic instability behavior., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 The Author(s).)

Dementia-related behavioral and psychology symptoms (BPSD) are undertreated and have negative consequences. However, families do not have access to disease information, tailored problem-solving  and effective management strategies, and with COVID-19, are more socially isolated and distressed. To address this dementia care gap, we describe a Phase III efficacy trial testing an online platform, WeCareAdvisor, and design modifications necessitated by COVID-19. WeCareAdvisor provides caregivers with disease information, daily tips, and a systematic approach for describing behaviors, investigating underlying causes, creating tailored strategies, and evaluating their effectiveness (DICE). The trial will enroll 326 caregivers nationwide, randomly assign them to immediately receive WeCareAdvisor (treatment), or a 3-month waitlist (control) and evaluate short (1- and 3-month) and long-term (6-month) outcomes for caregiver distress with and confidence managing BPSD, and BPSD occurrences. We will also evaluate utilization patterns with different prompting conditions: high-intensity (telephone and email reminders), low-intensity (email reminders), or no reminders to use WeCareAdvisor. COVID-19 necessitated design modifications resulting in greater inclusivity of caregivers from diverse races, ethnicities, and geographic areas. Key modifications include shifting from in-home, in-person interviewing to telephone; adjusting tool functionality from operating on a grant-funded iPad to caregivers' personal internet-capable devices; and expanding recruitment from one metropolitan area to nationwide. Study modifications necessitated by COVID-19 facilitate national outreach, easier tool adoption, and enable more diverse caregivers to participate. This study addresses a critical dementia care need, and design modifications may shorten timeline from efficacy testing to commercialization., Competing Interests: Conflict of InterestThe authors declare no competing interests., (© The Author(s) 2021.)

Structural mechanisms underlying the mechanical properties of fibrin fibers are elusive. We combined tensile testing of uncrosslinked fibrin polymers in vitro and in silico to explore their material properties. The experimental stress (σ) - strain (ε) curves for fibrin fibers are characterized by elastic deformations with a weaker elastic response for ε<160% due to unraveling of αC tethers and straightening of fibrin protofibrils, and a stronger response for ε>160% owing to unfolding of the coiled coils and γ nodules in fibrin monomers. Fiber rupture for strains ε>212% is due to dissociation of the knob-hole bonds and rupture of D:D interfaces. We developed the Fluctuating Bilinear Spring model to interpret the σ-ε profiles in terms of the free energy for protofibril alignment ΔG 0  = 10.1-11.5 k B T, Young's moduli for protofibril alignment Y u  = 1.9-3.2 MPa and stretching Y a  = 5.7-9.7 MPa, strain scale ε˜≈ 12-40% for fiber rupture, and protofibril cooperativity m= 3.6-8. We applied the model to characterize the fiber strength σ cr ≈ 12-13 MPa, deformability ε cr ≈ 222%, and rupture toughness U≈ 9 MJ/m 3 , and to resolve thermodynamic state functions, 96.9 GJ/mol entropy change for protofibril alignment (at room temperature) and 113.6 GJ/mol enthalpy change for protofibril stretching, which add up to 210.5 GJ/mol free-energy change. Fiber elongation is associated with protofibril dehydration and sliding mechanism to create an ordered protofibril array. Fibrin fibers behave like a hydrogel; protofibril dehydration and water expulsion account for ∼94-98% of the total free-energy changes for fiber elongation and rupture. STATEMENT OF SIGNIFICANCE: Structural mechanisms underlying the mechanical properties of fibrin fibers, major components of blood clots and obstructive thrombi, are elusive. We performed tensile testing of uncrosslinked fibrin polymers in vitro and in silico to explore their material properties. Fluctuating Bilinear Spring theory was developed to interpret the stress-strain profiles in terms of the energy for protofibril alignment, elastic moduli for protofibril alignment and stretching, and strain scale for fiber rupture, and to probe the limits of fiber strength, extensibility and toughness. Fibrin fibers behave like a hydrogel. Fiber elongation is defined by the protofibril dehydration and sliding. Structural rearrangements in water matrix control fiber elasticity. These results contribute to fundamental understanding of blood clot breakage that underlies thrombotic embolization., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

We developed the Fluctuating Nonlinear Spring (FNS) model to describe the dynamics of mechanical deformation of biological particles, such as virus capsids. The theory interprets the force-deformation spectra in terms of the "Hertzian stiffness" (non-linear regime of a particle's small-amplitude deformations), elastic constant (large-amplitude elastic deformations), and force range in which the particle's fracture occurs. The FNS theory enables one to quantify the particles' elasticity (Young's moduli for Hertzian and bending deformations), and the limits of their strength (critical forces, fracture toughness) and deformability (critical deformations) as well as the probability distributions of these properties, and to calculate the free energy changes for the particle's Hertzian, elastic, and plastic deformations, and eventual fracture. We applied the FNS theory to describe the protein capsids of bacteriophage P22, Human Adenovirus, and Herpes Simplex virus characterized by deformations before fracture that did not exceed 10-19% of their size. These nanoshells are soft (~1-10-GPa elastic modulus), with low ~50-480-kPa toughness - a regime of material behavior that is not well understood, and with the strength increasing while toughness decreases with their size. The particles' fracture is stochastic, with the average values of critical forces, critical deformations, and fracture toughness comparable with their standard deviations. The FNS theory predicts 0.7-MJ/mol free energy for P22 capsid maturation, and it could be extended to describe uniaxial deformation of cylindrical microtubules and ellipsoidal cellular organelles., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020. Published by Elsevier Ltd.)

Objectives: To evaluate whether a fall prevention intervention reduces fall risk in older adults who have previously fallen. Design: Randomized controlled pilot trial. Setting: Participants' homes. Intervention: LIVE-LiFE, adapted from Lifestyle-Intervention Functional Exercise (LiFE) integrates strength and balance training into daily habits in eight visits over 12 weeks. The adaptations to LiFE were to also provide (a) US$500 in home safety changes, (b) vision contrast screening and referral, and (c) medication recommendations. Control condition consisted of fall prevention materials and individualized fall risk summary. Measurement: Timed Up and Go (TUG) and Tandem stand. Falls efficacy, feasibility, and acceptability of the intervention. Results: Sample ( N = 37) was 65% female, 65% White, and average 77 years. Compared with the control group, each outcome improved in the intervention. The LIVE-LiFE intervention had a large effect (1.1) for tandem stand, moderate (0.5) in falls efficacy, and small (0.1) in the TUG. Conclusion: Simultaneously addressing preventable fall risk factors is feasible.

Development of antidotes against botulism requires understanding of the enzymatically active conformations of Botulinum neurotoxin serotype A (BoNT/A) light chain (LCA). We performed small angle X-ray scattering (SAXS) to characterize the solution structures of truncated light chain (tLCA). The 34-37 Å radius of gyration of tLCA was 1.5-times greater than the averaged 22-23-Å radius from the crystal structures. The bimodal distribution of interatomic distances P ( r ) indicated the two-domain tLCA structure with 129-133 Å size, and Kratky plots indicated the tLCA partial unfolding in the 25-37 °C temperature range. To interpret these data, we employed molecular dynamics simulations and machine learning. Excellent agreement between experimental and theoretical P ( r ) profiles helped to resolve conformational subpopulations of tLCA in solution. Partial unfolding of the C-terminal portion of tLCA (residues 339-425) results in formation of extended conformations with the larger globular domain (residues 2-298) and the smaller unstructured domain (339-425). The catalytic domain, buried 20 Å-deep inside the crystal structure, becomes accessible in extended solution conformations (8-9 Å deep). The C- and N-termini containing different functional sequence motifs are maximally separated in the extended conformations. Our results offer physical insights into the molecular basis of BoNT/A function and stress the importance of reversible unfolding-refolding transitions and hydrophobic interactions.

Importance: Neuropsychiatric behaviors of persons with dementia, including agitation, aggression, and rejection of care, are almost universal; occur throughout the disease process; and have negative consequences for both persons with dementia and their caregivers. Nonpharmacological approaches are now recognized as first-line treatment to address these behaviors. One promising approach is activity tailored to the person's interests, abilities, and physical and social environment. An evidence-based program, New Ways for Better Days: Tailoring Activities for Persons With Dementia and Their Caregivers (TAP), draws on occupational therapy principles (person-environment-occupation fit, activity analysis) to meaningfully engage persons with dementia., Objective: This case report describes the TAP protocol and clinical reasoning processes underlying use of tailored activities as a therapeutic modality to address dementia-related neuropsychiatric behaviors., Design: This is a case study of an African-American woman in her 60s caring for her father, age 92, who has severe dementia and multiple behaviors., Outcomes and Measures: Primary outcomes in this case report include the person with dementia's engagement in an activity and the reported neuropsychiatric behaviors. In addition, the caregiver's confidence in using activities is reported. These and other measures from the TAP protocol are described in full., Results: After working with an occupational therapist for eight sessions, the person with dementia's engagement in activity increased by 50% and his frequency of vocal disturbance decreased, and the caregiver felt more confident in using activities with her father., Conclusion and Relevance: This case report illustrates how occupational therapists working with families of persons with dementia can use the TAP protocol to help them manage neuropsychiatric behaviors by tailoring activities., What This Article Adds: Occupational therapists are uniquely qualified to systematically assess the cognitive functioning of persons with dementia, caregivers, and home environments and to integrate this information to derive and implement activities tailored to the person's capacities and context, thereby reducing neuropsychiatric behaviors and increasing engagement in meaningful activity., (Copyright © 2019 by the American Occupational Therapy Association, Inc.)

Fibrin formation and mechanical stability are essential in thrombosis and hemostasis. To reveal how mechanical load impacts fibrin, we carried out optical trap-based single-molecule forced unbinding experiments. The strength of noncovalent A:a knob-hole bond stabilizing fibrin polymers first increases with tensile force (catch bonds) and then decreases with force when the force exceeds a critical value (slip bonds). To provide the structural basis of catch-slip-bond behavior, we analyzed crystal structures and performed molecular modeling of A:a knob-hole complex. The movable flap (residues γ295 to γ305) containing the weak calcium-binding site γ2 serves as a tension sensor. Flap dissociation from the B domain in the γ-nodule and translocation to knob 'A' triggers hole 'a' closure, resulting in the increase of binding affinity and prolonged bond lifetimes. The discovery of biphasic kinetics of knob-hole bond rupture is quantitatively explained by using a theory, formulated in terms of structural transitions in the binding pocket between the low-affinity (slip) and high-affinity (catch) states. We provide a general framework to understand the mechanical response of protein pairs capable of tension-induced remodeling of their association interface. Strengthening of the A:a knob-hole bonds at 30- to 40-pN forces might favor formation of nascent fibrin clots subject to hydrodynamic shear in vivo., Competing Interests: The authors declare no conflict of interest.

A new computational methodology for the accurate numerical calculation of the Cauchy stress tensor, stress invariants, principal stress components, von Mises and Tresca tensors is developed. The methodology is based on the atomic stress approach which permits the calculation of stress tensors, widely used in continuum mechanics modeling of materials properties, using the output from the MD simulations of discrete atomic and [Formula: see text]-based coarse-grained structural models of biological particles. The methodology mapped into the software package TensorCalculator was successfully applied to the empty cowpea chlorotic mottle virus (CCMV) shell to explore the evolution of mechanical stress in this mechanically-tested specific example of a soft virus capsid. We found an inhomogeneous stress distribution in various portions of the CCMV structure and stress transfer from one portion of the virus structure to another, which also points to the importance of entropic effects, often ignored in finite element analysis and elastic network modeling. We formulate a criterion for elastic deformation using the first principal stress components. Furthermore, we show that von Mises and Tresca stress tensors can be used to predict the onset of a viral capsid's mechanical failure, which leads to total structural collapse. TensorCalculator can be used to study stress evolution and dynamics of defects in viral capsids and other large-size protein assemblies.

We carried out dynamic force manipulations in silico on a variety of coiled-coil protein fragments from myosin, chemotaxis receptor, vimentin, fibrin, and phenylalanine zippers that vary in size and topology of their α-helical packing. When stretched along the superhelical axis, all superhelices show elastic, plastic, and inelastic elongation regimes and undergo a dynamic transition from the α-helices to the β-sheets, which marks the onset of plastic deformation. Using the Abeyaratne-Knowles formulation of phase transitions, we developed a new theoretical methodology to model mechanical and kinetic properties of protein coiled-coils under mechanical nonequilibrium conditions and to map out their energy landscapes. The theory was successfully validated by comparing the simulated and theoretical force-strain spectra. We derived the scaling laws for the elastic force and the force for α-to-β transition, which can be used to understand natural proteins' properties as well as to rationally design novel biomaterials of required mechanical strength with desired balance between stiffness and plasticity.

Purpose of the Study: To evaluate feasibility of implementing the Tailored Activity Program for Hospitals (TAP-H) to improve engagement in patients with dementia admitted for behavioral disturbances., Design and Methods: TAP-H involves up to 11 in-hospital sessions to develop activities tailored to patient interests and capabilities and train staff/families in their use. Interventionists (occupational therapists) recorded session lengths, patient engagement (N = 20), and staff (N = 4) readiness to use activities. Family interviews (N = 20) identified patient behaviors at admission and satisfaction with TAP-H 1 month postdischarge. A time series design with multiple behavioral observations (63 videotaped sessions) compared affective, verbal, and nonverbal behavioral responses in a standardized activity (baseline) to treatment sessions., Results: Average number of treatment sessions per patient was 8.00 (SD = 2.71, range 3-13). Average time spent per session was 38.18min (SD = 10.01, range 19.09-57.50). Interventionists observed high patient engagement across treatment sessions. Observational data revealed increases in pleasure and positive gestures and decreases in anxiety/anger, negative verbalizations, and negative nonverbal behaviors from baseline to intervention sessions. Staff improved in readiness and families expressed high program satisfaction with 59.4% of activities used at home., Implications: TAP-H represents a unique collaborative care model that integrates facility-based staff in the behavioral treatment of patients with dementia and results in improved affect and reduced negative behaviors. TAP-H can be incorporated into routine hospital care and payment mechanisms. Future efforts should evaluate its effectiveness in reducing inappropriate pharmacologic use and strategies to enhance continued activity use by staff during hospitalization and families following discharge., (© The Author 2016. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Consumer health informatics (CHI) such as web-based applications may provide the platform for enabling the over 15 million family caregivers of patients with Alzheimer's Disease or related dementias the information they need when they need it to support behavioral symptom management. However, for CHI to be successful, it is necessary that it be designed to meet the specific information needs of family caregivers in the context in which caregiving occurs. A sociotechnical systems approach to CHI design can help to understand the contextual complexities of family caregiving and account for those complexities in the design of CHI for family caregivers., Objectives: This study used a sociotechnical systems approach to identify barriers to meeting caregivers' information needs related to the management of dementia-related behavioral symptoms, and to derive design implications that overcome barriers for caregiver-focused web-based platforms. We have subsequently used these design implications to inform the development of a web-based platform, WeCareAdvisor,TM which provides caregivers with information and an algorithm by which to identify and manage behavioral symptoms for which they seek management strategies., Methods: We conducted 4 focus groups with family caregivers (N=26) in a Midwestern state. Qualitative content analysis of the data was guided by a sociotechnical systems framework., Results: We identified nine categories of barriers that family caregivers confront in obtaining needed information about behavioral symptom management from which we extrapolated design implications for a web-based platform. Based on interactions within the sociotechnical system, three critical information needs were identified: 1) timely access to information, 2) access to information that is tailored or specific to caregiver's needs and contexts, and 3) usable information that can directly inform how caregivers' manage behaviors., Conclusions: The sociotechnical system framework is a useful approach for identifying information needs of family caregivers to inform design of web-based platforms that are user-centered.

The Problem: Mental health issues such as depression and neuropsychiatric symptoms (NPS) (e.g. agitation, aggression, rejection of care, wandering) are prevalent among residents in Assisted Living Facilities (ALF). Historically, these issues have only been treated with medications that can have a high risk of adverse effects in this population. This paper presents a scoping review of nonpharmacological interventions tested in ALFs for two of the most prevalent mental health issues: depression and NPS., Key Findings: Thirteen studies met inclusion criteria. Of those, eight (61.5%) found positive outcomes. Activity based and music therapy that utilize customization to interests and abilities showed the most promise., Tips for Success: Based on findings we offer five recommendations: 1) adopt evidence-based or evidence-informed interventions; 2) use tailored activity as a therapeutic modality; 3) adopt new training approaches for staff; 4) use emerging technologies for training and intervention; and 5) participate in practice based research.

Hydrodynamic interactions (HI) are incorporated into Langevin dynamics of the Cα -based protein model using the Truncated Expansion approximation (TEA) to the Rotne-Prager-Yamakawa diffusion tensor. Computational performance of the obtained GPU realization demonstrates the model's capability for describing protein systems of varying complexity (10(2) -10(5) residues), including biological particles (filaments, virus shells). Comparison of numerical accuracy of the TEA versus exact description of HI reveals similar results for the kinetics and thermodynamics of protein unfolding. The HI speed up and couple biomolecular transitions through cross-communication among protein domains, which result in more collective displacements of structure elements governed by more deterministic (less variable) dynamics. The force-extension/deformation spectra from nanomanipulations in silico exhibit sharper force signals that match well the experimental profiles. Hence, biomolecular simulations without HI overestimate the role of tension/stress fluctuations. Our findings establish the importance of incorporating implicit water-mediated many-body effects into theoretical modeling of dynamic processes involving biomolecules. © 2016 Wiley Periodicals, Inc., (© 2016 Wiley Periodicals, Inc.)

The mechanical properties of virus capsids correlate with local conformational dynamics in the capsid structure. They also reflect the required stability needed to withstand high internal pressures generated upon genome loading and contribute to the success of important events in viral infectivity, such as capsid maturation, genome uncoating and receptor binding. The mechanical properties of biological nanoparticles are often determined from monitoring their dynamic deformations in Atomic Force Microscopy nanoindentation experiments; but a comprehensive theory describing the full range of observed deformation behaviors has not previously been described. We present a new theory for modeling dynamic deformations of biological nanoparticles, which considers the non-linear Hertzian deformation, resulting from an indenter-particle physical contact, and the bending of curved elements (beams) modeling the particle structure. The beams' deformation beyond the critical point triggers a dynamic transition of the particle to the collapsed state. This extreme event is accompanied by a catastrophic force drop as observed in the experimental or simulated force (F)-deformation (X) spectra. The theory interprets fine features of the spectra, including the nonlinear components of the FX-curves, in terms of the Young's moduli for Hertzian and bending deformations, and the structural damage dependent beams' survival probability, in terms of the maximum strength and the cooperativity parameter. The theory is exemplified by successfully describing the deformation dynamics of natural nanoparticles through comparing theoretical curves with experimental force-deformation spectra for several virus particles. This approach provides a comprehensive description of the dynamic structural transitions in biological and artificial nanoparticles, which is essential for their optimal use in nanotechnology and nanomedicine applications.

Microtubules, the primary components of the chromosome segregation machinery, are stabilized by longitudinal and lateral noncovalent bonds between the tubulin subunits. However, the thermodynamics of these bonds and the microtubule physicochemical properties are poorly understood. Here, we explore the biomechanics of microtubule polymers using multiscale computational modeling and nanoindentations in silico of a contiguous microtubule fragment. A close match between the simulated and experimental force-deformation spectra enabled us to correlate the microtubule biomechanics with dynamic structural transitions at the nanoscale. Our mechanical testing revealed that the compressed MT behaves as a system of rigid elements interconnected through a network of lateral and longitudinal elastic bonds. The initial regime of continuous elastic deformation of the microtubule is followed by the transition regime, during which the microtubule lattice undergoes discrete structural changes, which include first the reversible dissociation of lateral bonds followed by irreversible dissociation of the longitudinal bonds. We have determined the free energies of dissociation of the lateral (6.9 ± 0.4 kcal/mol) and longitudinal (14.9 ± 1.5 kcal/mol) tubulin-tubulin bonds. These values in conjunction with the large flexural rigidity of tubulin protofilaments obtained (18,000-26,000 pN·nm(2)) support the idea that the disassembling microtubule is capable of generating a large mechanical force to move chromosomes during cell division. Our computational modeling offers a comprehensive quantitative platform to link molecular tubulin characteristics with the physiological behavior of microtubules. The developed in silico nanoindentation method provides a powerful tool for the exploration of biomechanical properties of other cytoskeletal and multiprotein assemblies.

Hospital clinical staff routinely confront challenging behaviors in patients with dementia with limited training in prevention and management. The authors of the current article conducted a survey of staff on a chronic care hospital unit concerning knowledge about dementia, perceived educational needs, and the care environment. The overall mean score for a 27-item knowledge scale was 24.08 (SD = 2.61), reflecting high level of disease knowledge. However, staff indicated a need for more information and skills, specifically for managing behaviors nonpharmacologically (92.3%), enhancing patient safety (89.7%), coping with care challenges (84.2%), and involving patients in activities (81.6%). Although most staff (i.e., nurses [80%] and therapists [86.4%]) believed their care contributed a great deal to patient well-being, approximately 75% reported frustration and being overwhelmed by dementia care. Most reported being hit, bitten, or physically hurt by patients (66.7%), as well as disrespected by families (53.8%). Findings suggest that staff have foundational knowledge but lack the "how-to" or hands-on skills necessary to implement nonpharmacological behavioral management approaches and communicate with families., (Copyright 2014, SLACK Incorporated.)

Background: Neuropsychiatric symptoms (NPS) occur in people with dementia throughout disease course and across etiologies. NPS are associated with significant morbidities and hastened disease processes. Nevertheless, people with dementia are not systematically assessed for NPS in clinical settings. We review existing NPS measures for clinical and/or research purposes, and identify measurement gaps., Methods: We conducted a computerized search of peer-reviewed published studies of measures (January 1, 1980-December 1, 2013) using multiple search terms. Measures selected for review were in English, had adequate psychometric properties, and were developed for or used with people with dementia. Papers describing measures were evaluated by three coders along seven characteristics: behavioral domains, number of items, method of administration, response categories, targeted population, setting, and psychometric properties., Results: Overall, 2,233 papers were identified through search terms, and 36 papers from manual searches of references. From 2,269 papers, 85 measures were identified of which 45 (52.9%) had adequate psychometric properties and were developed or used with dementia populations. Of these, 16 (35.6%) were general measures that included a wide range of behaviors; 29 (64.4%) targeted specific behaviors (e.g. agitation). Measures differed widely as to behaviors assessed and measurement properties., Conclusions: A robust set of diverse measures exists for assessing NPS in different settings. No measures identify risk factors for behaviors or enable an evaluation of the context in which behaviors occur. To improve clinical efforts, research is needed to evaluate concordance of behavioral ratings between formal and informal caregivers, and to develop and test measures that can identify known risks for behaviors and the circumstances under which behaviors occur.

Background: Homopolymeric tracts, particularly poly dA.dT, are enriched within the intergenic sequences of eukaryotic genomes where they appear to act as intrinsic regulators of nucleosome positioning. A previous study of the incomplete genome of the human malarial parasite Plasmodium falciparum reports a higher than expected enrichment of poly dA.dT tracts, far above that anticipated even in this highly AT rich genome. Here we report an analysis of the relative frequency, length and spatial arrangement of homopolymer tracts for the complete P. falciparum genome, extending this analysis to twelve additional genomes of Apicomplexan parasites important to human and animal health. In addition, using nucleosome-positioning data available for P. falciparum, we explore the correlation of poly dA.dT tracts with nucleosome-positioning data over key expression landmarks within intergenic regions., Results: We describe three apparent lineage-specific patterns of homopolymeric tract organization within the intergenic regions of these Apicomplexan parasites. Moreover, a striking pattern of enrichment of overly long poly dA.dT tracts in the intergenic regions of Plasmodium spp. uniquely extends into protein coding sequences. There is a conserved spatial arrangement of poly dA.dT immediately flanking open reading frames and over predicted core promoter sites. These key landmarks are all relatively depleted in nucleosomes in P. falciparum, as would be expected for poly dA.dT acting as nucleosome exclusion sequences., Conclusions: Previous comparative studies of homopolymer tract organization emphasize evolutionary diversity; this is the first report of such an analysis within a single phylum. Our data provide insights into the evolution of homopolymeric tracts and the selective pressures at play in their maintenance and expansion.

Physical properties of capsids of plant and animal viruses are important factors in capsid self-assembly, survival of viruses in the extracellular environment, and their cell infectivity. Combined AFM experiments and computational modeling on subsecond timescales of the indentation nanomechanics of Cowpea Chlorotic Mottle Virus capsid show that the capsid's physical properties are dynamic and local characteristics of the structure, which change with the depth of indentation and depend on the magnitude and geometry of mechanical input. Under large deformations, the Cowpea Chlorotic Mottle Virus capsid transitions to the collapsed state without substantial local structural alterations. The enthalpy change in this deformation state ΔHind = 11.5-12.8 MJ/mol is mostly due to large-amplitude out-of-plane excitations, which contribute to the capsid bending; the entropy change TΔSind = 5.1-5.8 MJ/mol is due to coherent in-plane rearrangements of protein chains, which mediate the capsid stiffening. Direct coupling of these modes defines the extent of (ir)reversibility of capsid indentation dynamics correlated with its (in)elastic mechanical response to the compressive force. This emerging picture illuminates how unique physico-chemical properties of protein nanoshells help define their structure and morphology, and determine their viruses' biological function., (Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.)

Polymerization of fibrin, the primary structural protein of blood clots and thrombi, occurs through binding of knobs 'A' and 'B' in the central nodule of fibrin monomer to complementary holes 'a' and 'b' in the γ- and β-nodules, respectively, of another monomer. We characterized the A:a and B:b knob-hole interactions under varying solution conditions using molecular dynamics simulations of the structural models of fibrin(ogen) fragment D complexed with synthetic peptides GPRP (knob 'A' mimetic) and GHRP (knob 'B' mimetic). The strength of A:a and B:b knob-hole complexes was roughly equal, decreasing with pulling force; however, the dissociation kinetics were sensitive to variations in acidity (pH 5-7) and temperature (T = 25-37 °C). There were similar structural changes in holes 'a' and 'b' during forced dissociation of the knob-hole complexes: elongation of loop I, stretching of the interior region, and translocation of the moveable flap. The disruption of the knob-hole interactions was not an "all-or-none" transition as it occurred through distinct two-step or single step pathways with or without intermediate states. The knob-hole bonds were stronger, tighter, and more brittle at pH 7 than at pH 5. The B:b knob-hole bonds were weaker, looser, and more compliant than the A:a knob-hole bonds at pH 7 but stronger, tighter, and less compliant at pH 5. Surprisingly, the knob-hole bonds were stronger, not weaker, at elevated temperature (T = 37 °C) compared with T = 25 °C due to the helix-to-coil transition in loop I that helps stabilize the bonds. These results provide detailed qualitative and quantitative characteristics underlying the most significant non-covalent interactions involved in fibrin polymerization.

Quartz crystal microbalances (QCMs) measure mass on the nanogram (ng) scale. We built novel QCMs as toxicity biosensors incorporating living cells. Human endothelial cells or canine macrophages were equilibrated on QCM crystal surfaces until stable oscillation frequencies occurred. Vehicle or sodium azide (NaN3) (25-100 mM) was added to these QCMs while continuously collecting crystal oscillation frequency data. At these doses, NaN3 alters mitochondrial membrane permeability and causes mitochondrial swelling and intrinsic apoptosis. Our studies demonstrated no frequency change in QCMs with untreated cells or without cells but NaN3. If NaN3 was added to either cell type within QCMs, 5 to 8 min later increases in oscillation frequency (Δf) occurred (400-1600 Hz) that correlated with dose. All frequency changes reverted to baseline by 15 min. In parallel, during the first 30 min, no change in cell or nuclear areas, or in actin or microtubule distributions, was detected. Yet, mitochondrial size and membrane permeability increased significantly during, but not after, 5 to 8 min. Viability studies confirmed dose-dependent toxicity that was predicted and proportionate to the 5- to 8-min Δf. These studies confirm that cell-based QCMs can detect early events in intrinsic apoptosis and reveal unique kinetic information about events occurring within subcellular structures in response to toxins., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Mouse strains C57BL/6 (B6) and MRL were studied by whole mouse genome chip microarray analyses of RNA isolated from amputation sites at different times pre- and postamputation at the midsecond phalange of the middle digit. Many keratin genes were highly differentially expressed. All keratin genes were placed into three temporal response classes determined by injury/preinjury ratios. One class, containing only Krt6 and Krt16, were uniquely expressed relative to the other two classes and exhibited different temporal responses in MRL vs. B6. Immunohistochemical staining for Krt6 and Krt16 in tissue sections, including normal digit, flank skin, and small intestine, and from normal and injured ear pinna tissue exhibited staining differences in B6 (low) and MRL (high) that were consistent with the microarray results. Krt10 staining showed no injury-induced differences, consistent with microarray expression. We analyzed Krt6 and Krt16 gene association networks and observed in uninjured tissue several genes with higher expression levels in MRL, but not B6, that were associated with the keratinocyte activated state: Krt6, Krt16, S100a8, S100a9, and Il1b; these data suggest that keratinocytes in the MRL strain, but not in B6, are in an activated state prior to wounding. These expression levels decreased in MRL at all times postwounding but rose in the B6, peaking at day 3. Other keratins significantly expressed in the normal basal keratinocyte state showed no significant strain differences. These data suggest that normal MRL skin is in a keratinocyte activated state, which may provide it with superior responses to wounding.

Human defensins play important roles in a broad range of biological functions, such as microbial defense and immunity. Yet, little is known about their molecular properties, i.e. secondary structure stability, structural variability, important side chain interactions, surface charge distribution, and resistance to thermal fluctuations, and how these properties are related to their functions. To assess these factors, we studied the native human β-defensin-1 monomer and dimer as well as several single-site mutants using molecular dynamics simulations. The results showed that disulfide bonds are important determinants in maintaining the defensins' structural integrity, as no structural transitions were observed at 300 K and only minor structural unfolding was detected upon heating to 500 K. The α-helix was less thermally stable than the core β-sheet structure held together by hydrogen bonds and hydrophobic interactions. The monomer α-helix stability was directly correlated, whereas the end-to-end distance was inversely correlated to the experimentally measured β-defensin-1 chemotactic activity, in the order: mutant 2 (Gln24Glu) > mutant 3 (Lys31Ala) = wild type > mutant 1 (Asn4Ala). The structural stability of the β-defensin-1 dimer species exhibited an inverse correlation to their chemotactic activity. In dimers formed by mutants 2 and 3, we observed sliding of one monomer upon the surface of the other in the absence of unbinding. This dynamic sliding feature may enhance the molecular oligomerization of β-defensin-1 peptides contributing to their antibacterial activity. It could also help these peptides orient correctly in the CC chemokine receptor 6 binding site, thereby initiating their chemotactic activity. In agreement with this notion, the remarkable sliding behavior was observed only for the mutants with the highest chemotactic activity.

Our research explores the correlates of spiritual experiences over a 2-year period in a sample of older adults (N = 164; mean age 81.9 years) living in a continuing care retirement community. Utilizing responses to the Daily Spiritual Experiences Scale, scores were analyzed for changes over time and for their hypothesized moderating effect in the relationship between chronic illness impact and markers of psychological well-being (as measured by the Geriatric Depression and Life Satisfaction scales). Repeated measures ANOVA indicated a significant decline (P < .01) in the reported spiritual experiences over a 2-year period of time, and t tests showed a significant difference by gender (P < .01) in years 1 and 2, with women reporting higher levels of spiritual experiences than men. Analyses found low spirituality scores associated with low life satisfaction in all years (baseline: r = -.288, P < .01; year 1: r = -.209, P < .05; year 2: r = -.330, P < .001). Only weak associations were detected between low spirituality and the presence of depressive symptoms at baseline (r = .186, P < .05) and year 2 (r = .254, P < .01). Moderation effects of spirituality on the relationship between chronic illness impact and markers of psychological well-being were explored in all years, with a statistically significant effect found only for the presence of depressive symptoms in year 2. Higher impact of chronic illnesses is associated with more depressive symptoms under conditions of low spirituality. Future research may center upon longer-duration evaluation of reliance upon spiritual practices and their impact in care management models.

The lactate dehydrogenase (LDH) assay accurately quantifies cytotoxicity of chemicals via the measurement of LDH released from damaged cells. In the assay, LDH catalyzes formation of a reporter chromophore that can be quantified spectrophotometrically at its 490 nm peak, a standard assay, and related to the released LDH concentration. However, certain engineered nanomaterials have been reported to produce aberrant values, resulting in inaccurate assessment of toxicity as measured by LDH levels in media. We studied this effect spectroscopically by measuring unexpected changes in the complete visible spectrum of the product chromophore resulting from using either purified LDH or LDH from lysed cells in the presence of varying concentrations of single walled carbon nanotubes (SWCNTs) or carbon nanohorns (SWCNH-oxs). Basically, at constant LDH concentrations, the 490 nm product peak decreased with increasing carbon nanotube concentration, while the 580 nm peak increased to a lesser extent and the maximum absorbing wavelength increased. The product chromophore spectrum was altered in different ways by potential interactions with a number of components in the reaction mixture including: BSA, LDH, SWCNTs, SWCNT-oxs, or various combinations of these species. We propose to improve the accuracy of the LDH assay when evaluated in the presence of varying concentrations of these carbon nanostructures by use of both the 490 and 580 nm peak absorbances combined via regression analysis. Our results indicate that molecular probes of cytotoxicity must be assessed individually for accuracy in the presence of engineered nanomaterials., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

During transformation of a normal cell to a cell capable of forming a cancerous growth, cellular morphology, the cytoskeleton, and focal contacts undergo significant changes. These changes should be capable of being characterized via real-time monitoring of the dynamic cell adhesion process and viscoelastic properties of cells. Here, we describe use of the quartz crystal microbalance (QCM) to distinguish the dynamic cell adhesion signatures of human normal (HMEC) versus malignant (MCF-7) mammary epithelial cells. The significantly reduced QCM responses (changes in frequency [Δf] and motional resistance ΔR) of MCF-7 cells compared with those of HMECs mirror the cancer cells' morphological features as observed via optical microscope. We analyzed the initial 2-h cell adhesion kinetics, suggesting cell-cell cooperativity for HMECs and no or weak cell-cell interactions for MCF-7 cells. We propose that changes of the ΔR/Δf ratio, which we term the cell viscoelastic index (CVI), reflect the establishment of cytoskeleton structure and dynamic viscoelastic properties of living cells. The CVI decreases significantly on initiation of cell to surface interactions as cells establish their cytoskeletal structures. During the cell adhesion process, MCF-7 cells were consistently softer, exhibiting up to a 2.5-fold smaller CVI when compared with HMECs., (Copyright © 2011 Elsevier Inc. All rights reserved.)

The inability to functionally repair tissues that are lost as a consequence of disease or injury remains a significant challenge for regenerative medicine. The molecular and cellular processes involved in complete restoration of tissue architecture and function are expected to be complex and remain largely unknown. Unlike humans, certain salamanders can completely regenerate injured tissues and lost appendages without scar formation. A parsimonious hypothesis would predict that all of these regenerative activities are regulated, at least in part, by a common set of genes. To test this hypothesis and identify genes that might control conserved regenerative processes, we performed a comprehensive microarray analysis of the early regenerative response in five regeneration-competent tissues from the newt Notophthalmus viridescens. Consistent with this hypothesis, we established a molecular signature for regeneration that consists of common genes or gene family members that exhibit dynamic differential regulation during regeneration in multiple tissue types. These genes include members of the matrix metalloproteinase family and its regulators, extracellular matrix components, genes involved in controlling cytoskeleton dynamics, and a variety of immune response factors. Gene Ontology term enrichment analysis validated and supported their functional activities in conserved regenerative processes. Surprisingly, dendrogram clustering and RadViz classification also revealed that each regenerative tissue had its own unique temporal expression profile, pointing to an inherent tissue-specific regenerative gene program. These new findings demand a reconsideration of how we conceptualize regenerative processes and how we devise new strategies for regenerative medicine.

Little is known about the health status of adults living in continuing care retirement communities (CCRC). Using matched-case control, 458 adults from the Health and Retirement Study (HRS) or a CCRC-based sample were compared on total comorbidity, self-rated health, home health services use, and hospitalizations. At year 2, the CCRC sample reported more comorbidities (96%) but significantly better self-rated health (96% good/excellent) than the HRS sample (93% comorbidity, 73% good/excellent; p < .01). There were no significant differences in frequency of home health use or hospitalization. Living in a CCRC appears to be associated with higher self-ratings of health in this sample.

Objective: To evaluate CarFit, an educational program designed to promote optimal alignment of driver with vehicle., Methods: A driving activity survey was sent to 727 randomly selected participants living in retirement communities. Drivers (n=195) were assigned randomly to CarFit intervention (n=83, M age=78.1) or Comparison (n=112, M age=79.6) groups. After 6months, participants completed a post-test of driving activity and CarFit recommendations., Results: Nonconsenting drivers were older and participated in fewer driving activities. CarFit participation was moderate (71%) with 86% of the participants receiving recommendations. 60% followed the recommendations at the 6-month re-evaluation). The CarFit (67.6%) and Comparison (59.3%) groups reported at least one type of self-regulation of driving activity at baseline. There was no significant change in the driving behaviors at the six-month follow-up., Conclusion: CarFit was able to detect addressable opportunities that may contribute to the safety of older drivers., Impact on Industry: CarFit recommendations may need stronger reinforcement in order to be enacted by a participant., (Copyright © 2011 National Safety Council and Elsevier Ltd. All rights reserved.)

Adults infected with HIV live longer when they receive regular medical care, yet many adults are not retained in care. Providers measure retention in order to evaluate interventions to improve retention and quality of HIV care. However, multiple measures for retention exist. This study compares two methods of operationalizing retention and evaluates the contribution of individual characteristics on the likelihood of retention. A chart review was performed for a random sample of 212 active clients of an urban HIV primary care clinic. Data on clinic utilization, sex, age, race, mental illness, substance use, AIDS diagnosis, language, and housing were collected for each participant. Clinic utilization data were used to classify participants for retention status and to score them by frequency of visits. Binary logistic regression analysis was compared with ordinal logistic regression analysis, using distinct retention measures as outcome variables. In the binary model, those with a history of substance use were about half as likely to be retained (OR 0.52, 95% CI 0.29-0.94) and those with an AIDS diagnosis were more than twice as likely to be retained (OR 2.18, 95% CI 1.17-4.09). These characteristics were significant predictors in the ordinal model, with the additional finding that those reporting English as a primary language were less likely to have higher retention scores (OR 0.40, 95% CI 0.19-0.84). An ordinal score for retention can identify unexpected predictors, but a dichotomous measure of retention may be easier to use and interpret for providers involved in retention-related quality improvement activities.

Background: Numerous engineered nanomaterials (ENMs) exist and new ENMs are being developed. A challenge to nanotoxicology and environmental health and safety is evaluating toxicity of ENMs before they become widely utilized. Cellular assays remain the predominant test platform yet these methods are limited by using discrete time endpoints and reliance on organic dyes, vulnerable to interference from ENMs. Label-free, continuous, rapid response systems with biologically meaningful endpoints are needed. We have developed a device to detect and monitor in real time responses of living cells to ENMs. The device, a living cell quartz crystal microbalance biosensor (QCMB), uses macrophages adherent to a quartz crystal. The communal response of macrophages to treatments is monitored continuously as changes in crystal oscillation frequency (Δf). We report the ability of this QCMB to distinguish benign from toxic exposures and reveal unique kinetic information about cellular responses to varying doses of single-walled carbon nanotubes (SWCNTs)., Results: We analyzed macrophage responses to additions of Zymosan A, polystyrene beads (PBs) (benign substances) or SWCNT (3-150 μg/ml) in the QCMB over 18 hrs. In parallel, toxicity was monitored over 24/48 hrs using conventional viability assays and histological stains to detect apoptosis. In the QCMB, a stable unchanging oscillation frequency occurred when cells alone, Zymosan A alone, PBs alone or SWCNTs without cells at the highest dose alone were used. With living cells in the QCMB, when Zymosan A, PBs or SWCNTs were added, a significant decrease in frequency occurred from 1-6 hrs. For SWCNTs, this Δf was dose-dependent. From 6-18 hrs, benign substances or low dose SWCNT (3-30 μg/ml) treatments showed a reversal of the decrease of oscillation frequency, returning to or exceeding pre-treatment levels. Cell recovery was confirmed in conventional assays. The lag time to see the Δf reversal in QCMB plots was linearly SWCNT-dose dependent. Lastly, the frequency never reversed at high dose SWCNT (100-150 μg/ml), and apoptosis/necrosis was documented in conventional 24 and 48 hr-assays., Conclusion: These data suggest that the new QCMB detects and provides unique information about peak, sub-lethal and toxic exposures of living cells to ENMs before they are detected using conventional cell assays.

The purpose of this study was to validate the six-item Men's Osteoporosis Knowledge Quiz (MOKQ). The MOKQ asks questions about risk factors that are pertinent to men, such as the risk for developing low bone mass related to hormone treatment for prostate cancer and the importance of testosterone for bone mass. A survey was sent to 242 men with a mean age of 83.2 years. The mean number of questions answered correctly in response to the six-item MOKQ was 2.37. Convergent validity was examined by correlating the score achieved on the MOKQ with the score achieved on the total Facts on Osteoporosis Quiz. The Pearson correlation coefficient for the MOKQ and the Facts on Osteoporosis Quiz was r = .76. Reliability was demonstrated by computing a Cronbach's alpha for the MOKQ (r = .72). The MOKQ was found to have adequate reliability and validity in assessing older men's knowledge about osteoporosis.

Objective: The prevalence of osteoporosis and low bone density in men over the age of 65 is approximately 45%. The public health response to a disease affecting almost half of a given population includes assessment of knowledge and design of educational interventions in order to improve screening and prevention. The aim of this systematic review is two fold. We aim to describe older men's knowledge about the osteoporosis disease process, risk factors, and prevention. Second, we examine educational interventions designed to increase older men's knowledge about osteoporosis., Methods: Computerized literature searches were performed with multiple databases including Academic Search Premier, CINAHL, MEDLINE, SocINDEX, and Psychology and Behavioral Sciences Collection. Studies were considered if they included men aged 50 years or older, included a measure of osteoporosis knowledge and/or had an intervention designed to change osteoporosis knowledge and/or lifestyle risk factors for osteoporosis., Results: Thirteen studies were included in the review. Nine of the studies were cross-sectional studies on men's knowledge of osteoporosis. All of the studies found that men have minimal knowledge of the osteoporosis disease process, risk factors, and prevention. Four studies focused on education about osteoporosis. Educational interventions were found to increase initiation of calcium supplementation and knowledge about osteoporosis prevention., Conclusion: Older men know remarkably little about the osteoporosis disease process, risk factors for the disease, or prevention. Education has the potential to improve this situation. Unfortunately, so few clinical trials have occurred that the best method for improving men's knowledge cannot be stated. Future studies examining knowledge and education of osteoporosis for men need to use validated instruments with a focus on risk factors pertinent to men., (Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.)