Stimulus-dependent dynamics of p53 in single cells

Many biological networks respond to various inputs through a common signaling molecule that triggers distinct cellular outcomes. One potential mechanism for achieving specific input-output relationships is to trigger distinct dynamical patterns in response to different stimuli. Here we focused on the dynamics of p53, a tumor suppressor activated in response to cellular stress. We quantified the dynamics of p53 in individual cells in response to UV and observed a single pulse that increases in amplitude and duration in proportion to the UV dose. This graded response contrasts with the previously described series of fixed pulses in response to γ-radiation. We further found that while γ-triggered p53 pulses are excitable, the p53 response to UV is not excitable and depends on continuous signaling from the input-sensing kinases. Using mathematical modeling and experiments, we identified feedback loops that contribute to specific features of the stimulus-dependent dynamics of p53, including excitability and input-duration dependency. Our study shows that different stresses elicit different temporal profiles of p53, suggesting that modulation of p53 dynamics might be used to achieve specificity in this network

Coyote (\u3ci\u3eCanis latrans\u3c/i\u3e) diet in an urban environment: variation relative to pet conflicts, housing density, and season

Coyotes (Canis latrans Say, 1823) are highly successful in urbanized environments, but as they populate cities, conflict can occur and often manifests in the form of incidents with pets. To better understand whether coyotes view pets as prey or, alternatively, as competitors or a threat, we conducted a diet analysis of coyotes in the Denver metropolitan area (DMA) by analyzing scats. We also examined differences in diet between high- and low-density housing and among seasons. We found only small percentages of trash and domestic pets in the coyote diet. The presence of pets in the diet did not coincide with the increase of pet conflicts in the DMA in December and January, supporting the hypothesis that coyote conflict with pets is primarily driven by competition or a threat response. Coyotes relied mostly on native plant and animal species, and rodents and lagomorphs were the most prevalent diet items. Coyotes consumed rodents and non-native plants more often in high-density housing and deer, corn, and native plants more often in low-density housing. Coyotes also consumed more fruits and invertebrates during summer and autumn and more mammals and birds in winter and spring. As human–coyote conflicts increase in urban areas, understanding how coyotes and other urban-adapted carnivores use anthropogenic resources may provide insight that can be used to promote coexistence between humans and wildlife

Brillouin light scattering study of Co2_{2}Cr0.6_{0.6}Fe0.4_{0.4}Al and Co2_{2}FeAl Heusler compounds

The thermal magnonic spectra of Co$_{2}$Cr$_{0.6}$Fe$_{0.4}$Al (CCFA) and Co$_2$FeAl were investigated using Brillouin light scattering spectroscopy (BLS). For CCFA, the exchange constant A (exchange stiffness D) is found to be 0.48 $\mu$erg/cm (203 meV A$^2$), while for Co$_2$FeAl the corresponding values of 1.55 $\mu$erg/cm (370 meV A$^2$) were found. The observed asymmetry in the BLS spectra between the Stokes and anti-Stokes frequencies was assigned to an interplay between the asymmetrical profiles of hybridized Damon-Esbach and perpendicular standing spin-wave modes, combined with the optical sensitivity of the BLS signal to the upper side of the CCFA or Co$_2$FeAl film

Control of radiative processes using tunable plasmonic nanopatch antennas.

The radiative processes associated with fluorophores and other radiating systems can be profoundly modified by their interaction with nanoplasmonic structures. Extreme electromagnetic environments can be created in plasmonic nanostructures or nanocavities, such as within the nanoscale gap region between two plasmonic nanoparticles, where the illuminating optical fields and the density of radiating modes are dramatically enhanced relative to vacuum. Unraveling the various mechanisms present in such coupled systems, and their impact on spontaneous emission and other radiative phenomena, however, requires a suitably reliable and precise means of tuning the plasmon resonance of the nanostructure while simultaneously preserving the electromagnetic characteristics of the enhancement region. Here, we achieve this control using a plasmonic platform consisting of colloidally synthesized nanocubes electromagnetically coupled to a metallic film. Each nanocube resembles a nanoscale patch antenna (or nanopatch) whose plasmon resonance can be changed independent of its local field enhancement. By varying the size of the nanopatch, we tune the plasmonic resonance by ∼ 200 nm, encompassing the excitation, absorption, and emission spectra corresponding to Cy5 fluorophores embedded within the gap region between nanopatch and film. By sweeping the plasmon resonance but keeping the field enhancements roughly fixed, we demonstrate fluorescence enhancements exceeding a factor of 30,000 with detector-limited enhancements of the spontaneous emission rate by a factor of 74. The experiments are supported by finite-element simulations that reveal design rules for optimized fluorescence enhancement or large Purcell factors

Assessing emergency medical care in low income countries: A pilot study from Pakistan

Background: Emergency Medical Care is an important component of health care system. Unfortunately it is however, ignored in many low income countries. We assessed the availability and quality of facility-based emergency medical care in the government health care system at district level in a low income country - Pakistan. Methods: We did a quantitative pilot study of a convenience sample of 22 rural and 20 urban health facilities in 2 districts - Faisalabad and Peshawar - in Pakistan. The study consisted of three separate cross-sectional assessments of selected community leaders, health care providers, and health care facilities. Three data collection instruments were created with input from existing models for facility assessment such as those used by the Joint Commission of Accreditation of Hospitals and the National Center for Health Statistics in USA and the Medical Research Council in Pakistan. Results: The majority of respondents 43/44(98%), in community survey were not satisfied with the emergency care provided. Most participants 36/44(82%) mentioned that they will not call an ambulance in health related emergency because it does not function properly in the government system. The expenses on emergency care for the last experience were reported to be less than 5,000 Pakistani Rupees (equivalent to US$ 83) for 19/29(66%) respondents. Most health care providers 43/44(98%) were of the opinion that their facilities were inadequately equipped to treat emergencies. The majority of facilities 31/42(74%) had no budget allocated for emergency care. A review of medications and equipment available showed that many critical supplies needed in an emergency were not found in these facilities. Conclusion: Assessment of emergency care should be part of health systems analysis in Pakistan. Multiple deficiencies in emergency care at the district level in Pakistan were noted in our study. Priority should be given to make emergency care responsive to needs in Pakistan. Specific efforts should be directed to equip emergency care at district facilities and to organize an ambulance network

Lithographic Patterning of Photoreactive Cell-Adhesive Proteins

We describe a novel, simple method for the photolithographic patterning of cell-adhesive proteins. Intrinsically photoreactive proteins are synthesized in Escherichia coli through incorporation of the non-canonical, photosensitive amino acid para-azidophenylalanine. Upon ultraviolet irradiation at 365 nm, proteins form cross-linked films with elastic moduli that can be tuned by varying the concentration of photoreactive amino acid in the expression medium. Films of these proteins can be directly patterned using standard photolithographic techniques. We demonstrate the utility of this method of protein patterning by creating stable arrays of fibroblast cells on an engineered protein “photoresist”

Incidence and pattern of injuries among residents of a rural area in South-Western Nigeria: a community-based study

<p>Abstract</p> <p>Background</p> <p>Despite the high incidence of infectious diseases in developing countries, injuries still contribute significantly to the health burden. There are few reports of rural, community-based injury surveys in Nigeria. This study describes the incidence and pattern of injuries among the residents of a rural area in South-Western Nigeria.</p> <p>Methods</p> <p>It was a community based cross-sectional study. Two of six census areas were randomly selected and all households in the two areas visited. Information on the sociodemographic characteristics, individual injury events and outcomes was obtained with a questionnaire. Data were analyzed using SPSS version 11.</p> <p>Results</p> <p>Information was obtained on the 1,766 persons in 395 households. Fifty-nine injuries were recorded by 54 people, giving an injury incidence of 100 per 1,000 per year (95% CI = 91.4–106.9). Injury incidence among <30 years was 81.6 per 1,000 per year (95% CI = 62.3–83.1); and 126 per 1,000 per year (95% CI = 98.2–137.4) for those ≥ 30 years (p = 0.013). Injury incidence for females was 46 per 1,000 per year; and 159 per 1,000 per year (p = 0.000) for males. A significantly higher proportion of males (5%) sustained injury compared to females (2%) (p = 0.043). Falls and traffic injures, 15 (25%) each, were the leading causes of injury; followed by cuts/stabs 12 (21%), and blunt injuries, 9 (15%). Traffic injuries were the leading cause of injuries in all age groups except among the 5–14 years where falls were the leading cause of injury. In thirty-four (58%) of those injuries, treatment was at a hospital/health centre; while in two (3%), treatment was by untrained traditional practitioners. Thirty-nine (66%) of the injuries were fully recovered from, and 19 (32%) resulted in disability. There were 2 fatalities in the 5-year period, one (2%) within the study period.</p> <p>Conclusion</p> <p>Injuries were common in Igbo-Ora, though resultant disability and fatality were low. Males and those aged ≥ 30 years had significantly higher proportions of the injured. Falls and traffic injuries were the most commonly reported injuries. Appropriate interventions to reduce the occurrences of injuries should be instituted by the local authorities. There is also need to educate the community members on how to prevent injuries.</p

Probing the ultimate limits of plasmonic enhancement.

Metals support surface plasmons at optical wavelengths and have the ability to localize light to subwavelength regions. The field enhancements that occur in these regions set the ultimate limitations on a wide range of nonlinear and quantum optical phenomena. We found that the dominant limiting factor is not the resistive loss of the metal, but rather the intrinsic nonlocality of its dielectric response. A semiclassical model of the electronic response of a metal places strict bounds on the ultimate field enhancement. To demonstrate the accuracy of this model, we studied optical scattering from gold nanoparticles spaced a few angstroms from a gold film. The bounds derived from the models and experiments impose limitations on all nanophotonic systems.Supported by Air Force Office of Scientific Research grant FA9550-09-1-0562 and by the Army Research Office through Multidisciplinary University Research Initiative grant W911NF-09-1-0539. Also supported by the Leverhulme Trust and the Marie Curie Actions (J.B.P., S.A.M., and A.I.F.-D.), NIH grant R21EB009862 (A.C.), and NIH F32 award F32EB009299 (R.T.H.)

Global distributed evolution of L-systems fractals

Internet based parallel genetic programming (GP) creates fractal patterns like Koch’s snow flake. Pfeiffer, http://www.cs.ucl.ac.uk/staff/W.Langdon/pfeiffer.html, by analogy with seed/embryo development, uses Lindenmayer grammars and LOGO style turtle graphics written in Javascript and Perl. 298 novel pictures were produced. Images are placed in animated snow globes (computerised snowstorms) by www web browsers anywhere on the planet. We discuss artificial life (Alife) evolving autonomous agents and virtual creatures in higher dimensions from a free format representation in the context of neutral networks, gene duplication and the evolution of higher order genetic operators