bluuebunny/crossref_metadata_2025 huggingface dataset:
An Inexpensive Mechanical Model for Projectile Motion
Authors: Kagan David
Published: April 2011

As experienced physicists, we see the beauty and simplicity of projectile motion. It is merely the superposition of uniform linear motion along the direction of the initial velocity vector and the downward motion due to the constant acceleration of gravity. We see the kinematic equations as just the mathematical machinery to perform the calculations. What do our students see? Likely, most see no deeper than the operational understanding needed to use the kinematic equations. Described below is a device (shown in Fig. 1) that illustrates the physicist's view of projectile motion. It can be used as a classroom demonstration or as a project for your students, and it costs less than three dollars to make.
A Simple, Successful Capacitor Lab
Authors: Ennis William
Published: April 2011

Capacitors are a fundamental component of modern electronics. They appear in myriad devices and in an enormous range of sizes. Although our students are taught the function and analysis of capacitors, few have the opportunity to use them in our labs.
A Teachable Moment Uncovered by Video Analysis
Authors: Gates Joshua
Published: April 2011

Early in their study of one-dimensional kinematics, my students build an algebraic model that describes the effects of a rolling ball's (perpendicular) collision with a wall. The goal is for the model to predict the ball's velocity when it returns to a fixed point approximately 50–100 cm from the wall as a function of its velocity as it passes this point initially. They are told to assume that the ball's velocity does not change while it rolls to or from the wall—that the velocity change all happens very quickly and only at the wall. In order to evaluate this assumption following the data collection, I have the students analyze one such collision using video analysis. The results uncover an excellent teachable moment about assumptions and their impact on models and error analysis.
Measuring Electrical Current: The Roads Not Taken
Authors: Greenslade Thomas B.
Published: April 2011

Recently I wrote about the standard Weston meter movement1,2 that is at the heart of all modern analogue current measurements. Now I will discuss other techniques used to measure electric current that, despite being based on valid physical principles, are largely lost in technological history.
The Cramster Conclusion
Authors: Grams Michael
Published: April 2011

In a recent TPT article,1 I wrote about a website called “Cramster” (www.cramster.com), which provides students with solutions to homework problems from many textbooks in math and science. I proposed the following question: Could giving students the answers to their assigned homework problems be an effective way of teaching them physics? This paper summarizes my findings after providing each of my students with solutions to every assigned homework problem over the course of one academic year.
Physics Labs with Flavor II
Authors: Agrest Mikhail M.
Published: April 2011

This paper was inspired by the numerous requests from TPT readers to expand the number of examples of “recurrent study” lab exercises described in my previous paper “Physics Labs with Flavor.”1 I recommend that readers examine it first in order to better understand this one as my attempt here is to be brief. In that paper, one can find details that are not included in this paper; here I aim to present how the essence of the recurrent method is applied to different labs. The examples used in this paper are based on the labs traditionally offered in lab manuals2–4 commonly used for introductory physics courses.
Special Relativity in Week One: 3) Introducing the Lorentz Contraction
Authors: Huggins Elisha
Published: April 2011

This is the third of four articles on teaching special relativity in the first week of an introductory physics course.1,2 With Einstein's second postulate that the speed of light is the same to all observers, we could use the light pulse clock to introduce time dilation. But we had difficulty introducing the Lorentz contraction until we saw the movie “Time Dilation, an Experiment with Mu-Mesons” by David Frisch and James Smith.3,4 The movie demonstrates that time dilation and the Lorentz contraction are essentially two sides of the same coin. Here we take the muon's point of view for a more intuitive understanding of the Lorentz contraction, and use the results of the movie to provide an insight into the way we interpret experimental results involving special relativity.
Minute of physics
Authors: Page Katie
Published: April 2011

It's 7:23 a.m. sometime last fall, students are running through the halls to get to class, and as I stand in my doorway greeting kids, I notice that only about 2/3 of my students are seated and ready to go. 7:24…7:25, the final bell rings. As the next few minutes roll past, students continue to stroll in with a glare from me. I decided to try something new to get students to class on time, and, after some research, the “Minute of Physics” was born.
Association of TALS Developmental Disorder with Defect in Minor Splicing Component
U4atac
snRNA
Authors: Edery Patrick , Marcaillou Charles , Sahbatou Mourad , Labalme Audrey , Chastang Joelle , Touraine Renaud , Tubacher Emmanuel , Senni Faiza , Bober Michael B. , Nampoothiri Sheela , Jouk Pierre-Simon , Steichen Elisabeth , Berland Siren , Toutain Annick , Wise Carol A. , Sanlaville Damien , Rousseau Francis , Clerget-Darpoux Françoise , Leutenegger Anne-Louise
Published: April 2011

Mutation in a small nuclear RNA hinders splicing of pre–messenger RNAs and causes the severe malformations of Taybi-Linder syndrome.
Oriented 2D Covalent Organic Framework Thin Films on Single-Layer Graphene
Authors: Colson John W. , Woll Arthur R. , Mukherjee Arnab , Levendorf Mark P. , Spitler Eric L. , Shields Virgil B. , Spencer Michael G. , Park Jiwoong , Dichtel William R.
Published: April 2011

Microporous covalent organic frameworks, which usually form as insoluble powders, grow as crystalline films on graphene.
Neuronal GPCR Controls Innate Immunity by Regulating Noncanonical Unfolded Protein Response Genes
Authors: Sun Jingru , Singh Varsha , Kajino-Sakamoto Rie , Aballay Alejandro
Published: April 2011

Two nematode worm neurons “smell” disease and promote resistance to pathogens.
The Phase Behavior of Interfaces
Authors: Harmer Martin P.
Published: April 2011

Grain boundaries between crystals, which can control materials properties, can interconvert between well-defined equilibrium structures.
Merged Cultures to Empower Women
Authors: Jones Kerri-Ann , Malcom Shirley , Hrynkow Sharon
Published: April 2011

The 55th session of the Commission on the Status of Women (CSW) of the United Nations (UN) closed last month with little fanfare, but there was cause for celebration. For the first time, the CSW, traditionally a forum to examine improvement of women's rights and gender equality, merged this broad interest with issues of science and technology (S&T). This makes sense because empowering women as scientists and engineers, supporting girls' education in science, and valuing women as builders of economic development all contribute to gender equality. The merger of these two areas produced recommendations to governments and nongovernmental entities that go far beyond what either group would likely have developed independently.
DOE Pulls the Plug on Massive Training Initiative
Authors: Mervis Jeffrey
Published: April 2011

The White House has dropped an ambitious 10-year, $1.6 billion education and training initiative at the Department of Energy, dubbed "Regaining our Energy Science and Engineering Edge," from DOE's 2012 budget request.
Scientist in the Middle of the GM-Organic Wars
Authors: Charles Dan
Published: April 2011

For Carol Mallory-Smith of Oregon State University, the migration of genes in agricultural crops is not just a research topic or a matter of policy debate. It's the cause of a vexing quarrel among her neighbors: the farmers of Oregon's Willamette Valley.
Search for Majorana Fermions Nearing Success at Last?
Authors: Service Robert F.
Published: April 2011

Researchers think they are on the verge of discovering weird new particles that borrow a trick from superconductors and could give a big boost to quantum computers.
Solution of a heterogeneous modeling of a horizontal-flow anaerobic immobilized biomass (HAIB) reactor by the sequencing method
Authors: Cuel Maressa Fabiano , Kwong Wu Hong , Zaiat Marcelo , Foresti Eugenio
Published: April 2011

A modeling study was completed to develop a methodology that combines the sequencing and finite difference methods for the simulation of a heterogeneous model of a tubular reactor applied in the treatment of wastewater. The system included a liquid phase (convection–diffusion–transport) and a solid phase (diffusion reaction) that was obtained by completing a mass balance in the reactor and in the particle, respectively. The model was solved using a pilot-scale horizontal-flow anaerobic immobilized biomass (HAIB) reactor to treat domestic sewage, with the concentration results compared with the experimental data. A comparison of the behavior of the liquid phase concentration profile and the experimental results indicated that both the numerical methods offer a good description of the behavior of the concentration along the reactor. The advantage of the sequencing method over the finite difference method is that it is easier to apply and requires less computational time to model the dynamic simulation of outlet response of HAIB.
Adaptation options to reduce climate change vulnerability of sustainable forest management in the Austrian Alps
Authors: Seidl Rupert , Rammer Werner , Lexer Manfred J.
Published: April 2011

Sustaining forest ecosystem functions and services under climate change is a major challenge for forest management. While conceptual advances of adapting coupled social–ecological systems to environmental changes have been made recently, good practice examples at the operational level still remain rare. The current study presents the development of adaptation options for 164 550 ha of commercial forests under the stewardship of the Austrian Federal Forests (AFF). We used a comprehensive vulnerability assessment as analysis framework, employing ecosystem modeling and multicriteria decision analysis in a participatory approach with forest planers of the AFF. An assessment of the vulnerability of multiple ecosystem goods and services under current management served as the starting point for the development of adaptation options. Measures found to successfully reduce vulnerability include the promotion of mixed stands of species well adapted to emerging environmental conditions, silvicultural techniques fostering complexity, and increased management intensity. Assessment results for a wide range of site and stand conditions, stand treatment programs, and future climate scenarios were used to condense robust recommendations for adapting the management guidelines currently used by AFF practitioners. Overall, our results highlight the importance of timely adaptation to sustain forest goods and services and document the respective potential of silvicultural measures.
Public views on forest management: value orientation and forest dependency as indicators of diversity
Authors: McFarlane Bonita L. , Beckley Thomas M. , Huddart-Kennedy Emily , Nadeau Solange , Wyatt Stephen
Published: April 2011

Classifying communities as forest dependent based on economic indicators implies that residents of these communities share a utilitarian view of forest management whereby resource extraction and economic benefits are the primary focus. In this study, we test this hypothesis by examining the relationship between forest dependency, value orientation, and views on forest management. Data were collected by mail survey from 1521 residents of the Province of New Brunswick, Canada, in 2007. We classify respondents based on levels of forest dependency of their area of residence and their forest value orientation. We examine variation in beliefs about forest management, goals of forest management, and public involvement across levels of forest dependency and forest value orientation. Results showed some differences among residents from regions with different levels of forest dependence. Considerably greater variation, however, occurred among forest value orientation clusters. This study suggests that regardless of the level of forest dependency, communities comprised a mix of value orientations and that examining populations based on level of forest dependency may mask a plurality of views on forest management within communities.
Identification and characterization of the contact zone between short-tailed shrews (Blarina) in Iowa and Missouri
Authors: Thompson C.W. , Pfau R.S. , Choate J.R. , Genoways H.H. , Finck E.J.
Published: April 2011

Short-tailed shrews (genus Blarina Gray, 1838) are characterized by divergent karyotypes and are genetically distinct. Blarina species are similar morphologically but, in most cases, can be distinguished morphometrically. Blarina distributions tend to be parapatric along well-defined contact zones; however, it has been suggested that the northern short-tailed shrew ( Blarina brevicauda (Say, 1823)) and Elliot’s short-tailed shrew ( Blarina hylophaga Elliot, 1899) occur sympatrically in Iowa and Missouri. To evaluate this possibility, 179 specimens were collected in southwestern Iowa and northwestern Missouri. Karyotypes and total length were used for field identification, and amplified fragment length polymorphism (AFLP) analysis was used to verify field identifications and to investigate the extent of hybridization. One hundred seventy-eight of 179 specimens were identified to species. The one exception had a karyotype of B. brevicauda (2n = 50, FN = 48); however, AFLP analysis indicated that this individual was likely an F1hybrid. No backcrosses were detected, so it appears that introgression is minimal. The putative hybrid was trapped at a locality with B. brevicauda just north of a locality having only B. hylophaga. No locality contained both species. Therefore, these species are not broadly sympatric as has been suggested, but rather exhibit a distribution similar to the pattern of parapatry seen in most of the contact zones of Blarina.
Exploring male and female preferences, male body condition, and pair bonds in the evolution of male sexual aggregation: the case of the Common Quail (Coturnix coturnix)
Authors: Sardà-Palomera F. , Puigcerver M. , Vinyoles D. , Rodríguez-Teijeiro J.D.
Published: April 2011

One of the unresolved problems of male sexual aggregations is that a small number of males monopolize most matings. The Common Quail ( Coturnix coturnix (L., 1758)), is a bird species that has a short life span and a reproductive strategy that involves male aggregations, which females visit for the purpose of mating. Once a mate has been chosen, birds leave the aggregation and form pair-bonds until incubation begins. This remarkable mating system might represent an intermediate step between lekking and pair-bond mating systems in which males provide some parental care. We designed a field experiment with funnel traps simulating male groups and single females to observe male and female preferences, and to examine the possible evolutionary process that drives males to aggregate. Radio-tagged individuals were also monitored to study pair-bonding behaviour in the field. Our results suggest that body condition is an important factor in male group formation, and that males with better body condition tend to aggregate, while males in poorer condition wait for extra-pair copulation opportunities. Moreover, this mating system creates a situation in which a queuing strategy might occur.
Foraging space as a limited resource: inter- and intra-specific competition among sympatric pursuit-diving seabirds
Authors: Ronconi R.A. , Burger A.E.
Published: April 2011

Competition is thought to play a fundamental role in structuring avian communities, yet this has been difficult to quantify and demonstrate in marine ecosystems. We tested for fine-scale competition over foraging space between sympatric pursuit-diving seabirds, Marbled Murrelet ( Brachyramphus marmoratus (J.F. Gmelin, 1789)) and Common Murre ( Uria aalge (Pontoppidan, 1763)). We simultaneous assessed the effects of inter- and intra-specific competition among these predators, predicting that the larger Common Murres would out-compete the smaller Marbled Murrelets for foraging space. A theodolite was used to map the fine-scale (±2 m) distributions of birds on the water; distance from shore measurements and nearest-neighbour spatial statistics quantified the spatial overlap and segregation between species. Species distributions differed with respect to distance from shore, but overlapped extensively within 1200 m of the shoreline. Nearest-neighbour statistics, assessed with randomization tests, showed Marbled Murrelets foraging farther from Common Murres (mean distances 294 m) than from other Marbled Murrelets (95 m), but groups of Common Murres foraged with similar spacing among conspecifics (266 m) and competitors (186 m). These results suggest avoidance of Common Murres by Marbled Murrelets (interspecific competition) but intraspecifc competition among Common Murres. Avoidance behaviour may minimize the impacts of aggression or competition, but by avoiding Common Murres, the Marbled Murrelets may also be reducing their foraging opportunities.
VALIDITY OF THE THERMODYNAMICAL PROPERTIES OF THE DARK ENERGY MODEL WITH THE EQUATION OF STATE: w = w0 + w1 · z(1 + z)/(1 + z2)
Authors: XING LILI , CHEN JIANBIN , GUI YUANXING , SCHLEGEL ERIC M. , LU JIANBO
Published: April 2011

We investigate the validity of the thermodynamical properties of the universe in a new parametric model of dark energy with the equation of state w = w0 + w1 · z(1 + z)/(1 + z2). In the spatially homogeneous and isotropic universe, assuming that the temperature and entropy in cosmology is as in a black hole, we examine the thermodynamical properties of the universe bounded by the apparent horizon and the event horizon respectively. By analysis, we find that the first and the second laws of thermodynamics are valid inside the apparent horizon, while they break down inside the event horizon.
ON THIN-SHELL WORMHOLES EVOLVING IN FLAT FRW SPACETIMES
Authors: LA CAMERA M.
Published: April 2011

We analyze the stability of a class of thin-shell wormholes with spherical symmetry evolving in flat FRW spacetimes. The wormholes considered here are supported at the throat by a perfect fluid with equation of state [Formula: see text] and have a physical radius equal to aR, where a is a time-dependent function describing the dynamics of the throat and R is the background scale factor. The study of wormhole stability is done by means of the stability analysis of dynamic systems.
COMPUTATION OF INTERACTION POTENTIAL OF ADSORBATES ON ZIGZAG SWCNTs — APPLICATION TO FUNCTIONALIZATION AND HYDROGEN STORAGE
Authors: LAKSHMI I. , SILAMBARASAN D. , SURYA V. J. , RAJARAJESWARI M. , IYAKUTTI K. , MIZUSEKI H. , KAWAZOE Y.
Published: April 2011

Nature of the interaction potential of different adsorbates on different zigzag single-walled carbon nanotubes is investigated. The intermolecular potentials for H2 absorbed in carbon nanotubes (5, 0), (6, 0), (7, 0), (8, 0), (9, 0), and (10, 0) are computed and sketched. This study is extended to N2 adsorbed on (4, 0) and BH3 adsorbed on (10, 0) tubes. The equilibrium positions of the adsorbates obtained from the potential model serve as an initial guess in designing the CNT + adsorbate complex in the simulation cell and this process considerably reduces the computation time. Further, the hydrogen storage capacity of CNT(10,0) + BH3 complex is calculated. The estimated storage capacity of this system is in the range 6–12 wt.%.
NONLINEAR VIBRATION AND BENDING INSTABILITY OF A SINGLE-WALLED CARBON NANOTUBE USING NONLOCAL ELASTIC BEAM THEORY
Authors: MEHDIPOUR I. , SOLTANI P. , GANJI D. D. , FARSHIDIANFAR A.
Published: April 2011

Due to the nonlocal Euler–Bernoulli elastic beam theory, the effects of rippling deformation on the bending modulus and the structural bending instability of a single-walled carbon nanotube (SWCNT) are investigated. The nonlinear vibrational model of a cantilevered SWCNT is solved using the perturbation method of multiscales. The nonlinear resonant frequency and the associated effective bending modulus of the carbon nanotube (CNT) are derived analytically. The effects of the nonlocal parameter, the external harmonic force, and the diameter-to-length ratio on the effective bending modulus are discussed widely. Moreover, the model can predict special kind of structural instability due to the rippling deformation called rippling instability. The results show that the nonlocal theory forecasts larger values for the effective bending modulus compared with the classical beam theory, especially for the stubby CNTs. Meanwhile, the rippling instability threshold will move to the higher values of the diameter-to-length ratio based on the nonlocal beam theory comparing with the local ones.
CONTROLLED SYNTHESIS AND CHARACTERIZATION OF CERIUM-DOPED ZnS NANOPARTICLES IN HMTA MATRIX
Authors: ANAND K. VIJAI , MOHAN R. , KUMAR R. MOHAN , CHINNU M. KARL , JAYAVEL R.
Published: April 2011

Cerium-doped ZnS nanoparticles have been synthesized through hydrothermal method. The nanoparticles were stabilized using hexamethylenetetramine (HMTA) as surfactant in aqueous solution. The average particle size of the prepared samples is about 2 nm. The structure of the as-prepared ZnS nanoparticles is cubic (zinc blende) as demonstrated by X-ray powder diffraction (XRD) and selected area electron diffraction (SAED) analysis. TEM results showed that the synthesized nanoparticles were uniformly dispersed in the HMTA matrix without aggregation. The UV–Vis absorption spectra of the prepared ZnS nanoparticles show a considerable blueshift in the absorption band edge compared to bulk ZnS indicating a strong quantum confinement effect. Formation of HMTA-capped ZnS nanoparticles was confirmed by FTIR studies. Photoluminescence studies showed that the relative emission intensity of Ce3+ -doped ZnS nanoparticles is higher than that of undoped ZnS nanoparticles, which is due to the enhancement of radiative recombination in the luminescence process. The PL spectra showed two emission peaks at around 420 nm and 442 nm, which may be attributed to deep-trap emission or defect-related emission of ZnS and presence of various surface states.
BIREFRINGENCE AND MAGNETO-OPTICAL PROPERTIES IN OLEIC ACID COATED Fe3O4 NANOPARTICLES: APPLICATION FOR OPTICAL SWITCH
Authors: XIA SI-HUA , WANG JUN , LU ZHANG-XIAN , ZHANG FEIYAN
Published: April 2011

We report magneto-optical properties in a kerosene colloidal suspension of oleic acid coated Fe3O4 nanoparticles (~14 nm). The magnetic colloids (fluids) show birefringence under a magnetic field. Systematical studies of the on–off switch times upon application of the on–off magnetic field with varied experimental parameters indicate that the switch response time depends strongly on the strength of the magnetic field and the concentration of the magnetic nanoparticles in the fluid. The data can be explained in terms of the formation of magnetic nanoparticle chains under a magnetic field. The important magneto-optical properties of the magnetic fluids allow us to design a tunable optical switch.
HOW DOES ANESTHESIA AFFECT VARIOUS LEVELS OF EXPERIMENTAL TRAUMATIC BRAIN INJURY?
Authors: EFRAT BARBIRO-MICHAELY , TAMAR MANOR , GENNADY ROGATSKY , AVRAHAM MAYEVSKY
Published: April 2011

The use of anesthetics is a well-known treatment for severely injured patients. In the present study we tested the pathophysiology of several levels of injury damage in a rat model and also tested the effect of Equithesin on brain vitality in these models. Traumatic Brain Injury (TBI) was induced using the fluid percussion injury model in four levels: mild, moderate and two levels of severe TBI. Brain real-time evaluation was performed by the multiparametric monitoring assembly (MPA) which enable cerebral blood flow (CBF) monitoring by laser Doppler flowmetry, mitochondrial NADH (Nicotinamide adenine dinucleotide) monitoring by the fluorometric technique, ionic homehostasis using special mini-electrodes, intracranial pressure (ICP) by the ICP camino device and needle electrodes for ECoG (Electrocorticogram) recording. Our results showed high correlation between the level of impact and the extent of changes in the physiological properties of the injury as indicated by the changes in all parameters monitored using the MPA device. Moreover, Equithesin improved CBF, ionic extracellular level and mitochondrial redox state following mild and moderate TBI while in severe TBI, Equithesin did not improve the metabolic state of the cerebral cortex, although it decreased the mortality rate from 66% to 20%, and following extra-severe TBI level, Equithesin did not improve survival rate. In conclusion it seems that Equithesin's protective effect exists under mild to moderate levels of injury and not in case of severe injuries.
SUBNATIONAL TAXATION IN DEVELOPING COUNTRIES: A REVIEW OF THE LITERATURE
Authors: BIRD RICHARD M.
Published: April 2011

This paper reviews the literature on tax assignment in decentralised countries. Ideally, own-source revenues should be sufficient to enable at least the richest subnational governments to finance from their own resources all locally-provided services that primarily benefit local residents. Subnational taxes should also not unduly distort the allocation of resources. Most importantly, to the extent, possible subnational governments should be accountable at the margin for financing the expenditures for which they are responsible. Overall, the 'best' package for any particular country or subnational government is likely to be not only context-specific and path-dependent, but also highly sensitive to the balance struck between different political and economic factors and interests.
Heterogeneous accumulation of fluorescent bile acids in primary rat hepatocytes does not correlate with their homogenous expression of ntcp
Authors: Murray John W. , Thosani Amar J. , Wang Pijun , Wolkoff Allan W.
Published: April 2011

Sodium taurocholate-cotransporting polypeptide (ntcp) is considered to be a major determinant of bile acid uptake into hepatocytes. However, the regulation of ntcp and the degree that it participates in the accumulation of specific substrates are not well understood. We utilized fluorescent bile acid derivatives and direct quantitation of fluorescent microscopy images to examine the regulation of ntcp and its role in the cell-to-cell variability of fluorescent bile acid accumulation. Primary-cultured rat hepatocytes rapidly accumulated the fluorescent bile acids, chenodeoxycholylglycylamidofluorescein (CDCGamF), 7-β- nitrobenzoxadiazole 3-α hydroxy 5-β cholan-24-oic acid (NBD-CA), and cholyl-glycylamido-fluorescein (CGamF). However, in stably transfected HeLa cells, ntcp preferred CDCGamF, whereas the organic anion transporter, organic anion transporting polypeptide 1 (oatp1a1), preferred NBD-CA, and neither ntcp nor oatp1a1 showed strong accumulation of CGamF by these methods. Ntcp-mediated transport of CDCGamF was inhibited by taurocholate, cyclosporin, actin depolymerization, and an inhibitor of atypical PKC-ζ. The latter two agents altered the cellular distribution of ntcp as visualized in ntcp-green fluorescent protein-transfected cells. Although fluorescent bile acid accumulation was reproducible by the imaging assays, individual cells showed variable accumulation that was not attributable to changes in membrane permeability or cell viability. In HeLa cells, this was accounted for by variable levels of ntcp, whereas, in hepatocytes, ntcp expression was uniform, and low accumulation was seen in a large portion of cells despite the presence of ntcp. These studies indicate that single-cell imaging can provide insight into previously unrecognized details of anion transport in the complex environment of polarized hepatocytes.
Sex differences in physiological cardiac hypertrophy are associated with exercise-mediated changes in energy substrate availability
Authors: Foryst-Ludwig Anna , Kreissl Michael C. , Sprang Christiane , Thalke Beata , Böhm Christian , Benz Verena , Gürgen Dennis , Dragun Duska , Schubert Carola , Mai Knut , Stawowy Philipp , Spranger Joachim , Regitz-Zagrosek Vera , Unger Thomas , Kintscher Ulrich
Published: April 2011

Exercise-induced cardiac hypertrophy has been recently identified to be regulated in a sex-specific manner. In parallel, women exhibit enhanced exercise-mediated lipolysis compared with men, which might be linked to cardiac responses. The aim of the present study was to assess if previously reported sex-dependent differences in the cardiac hypertrophic response during exercise are associated with differences in cardiac energy substrate availability/utilization. Female and male C57BL/6J mice were challenged with active treadmill running for 1.5 h/day (0.25 m/s) over 4 wk. Mice underwent cardiac and metabolic phenotyping including echocardiography, small-animal PET, peri-exercise indirect calorimetry, and analysis of adipose tissue (AT) lipolysis and cardiac gene expression. Female mice exhibited increased cardiac hypertrophic responses to exercise compared with male mice, measured by echocardiography [percent increase in left ventricular mass (LVM): female: 22.2 ± 0.8%, male: 9.0 ± 0.2%; P < 0.05]. This was associated with increased plasma free fatty acid (FFA) levels and augmented AT lipolysis in female mice after training, whereas FFA levels from male mice decreased. The respiratory quotient during exercise was significantly lower in female mice indicative for preferential utilization of fatty acids. In parallel, myocardial glucose uptake was reduced in female mice after exercise, analyzed by PET {injection dose (ID)/LVM [%ID/g]: 36.8 ± 3.5 female sedentary vs. 28.3 ± 4.3 female training; P < 0.05}, whereas cardiac glucose uptake was unaltered after exercise in male counterparts. Cardiac genes involved in fatty acid uptake/oxidation in females were increased compared with male mice. Collectively, our data demonstrate that sex differences in exercise-induced cardiac hypertrophy are associated with changes in cardiac substrate availability and utilization.
Angiotensin II and norepinephrine activate specific calcineurin-dependent NFAT transcription factor isoforms in cardiomyocytes
Authors: Lunde Ida G. , Kvaløy Heidi , Austbø Bjørg , Christensen Geir , Carlson Cathrine R.
Published: April 2011

Norepinephrine (NE) and angiotensin II (ANG II) are primary effectors of the sympathetic adrenergic and the renin-angiotensin-aldosterone systems, mediating hypertrophic, apoptotic, and fibrotic events in the myocardium. As NE and ANG II have been shown to affect intracellular calcium in cardiomyocytes, we hypothesized that they activate the calcium-sensitive, prohypertrophic calcineurin-nuclear factor of activated T-cell (NFATc) signaling pathway. More specifically, we have investigated isoform-specific activation of NFAT in NE- and ANG II-stimulated cardiomyocytes, as it is likely that each of the four calcineurin-dependent isoforms, c1-c4, play specific roles. We have stimulated neonatal ventriculocytes from C57/B6 and NFAT-luciferase reporter mice with ANG II or NE and quantified NFAT activity by luciferase activity and phospho-immunoblotting. ANG II and NE increased calcineurin-dependent NFAT activity 2.4- and 1.9-fold, measured as luciferase activity after 24 h of stimulation, and induced protein synthesis, measured by radioactive leucine incorporation after 24 and 72 h. To optimize measurements of NFAT isoforms, we examined the specificity of NFAT antibodies on peptide arrays and by immunoblotting with designed blocking peptides. Western analyses showed that both effectors activate NFATc1 and c4, while NFATc2 activity was regulated by NE only, as measured by phospho-NFAT levels. Neither ANG II nor NE activated NFATc3. As today's main therapies for heart failure aim at antagonizing the adrenergic and renin-angiotensin-aldosterone systems, understanding their intracellular actions is of importance, and our data, through validating a method for measuring myocardial NFATs, indicate that ANG II and NE activate specific NFATc isoforms in cardiomyocytes.
A New BATTLE in the Evolving War on Cancer
Authors: Sequist Lecia V. , Muzikansky Alona , Engelman Jeffrey A.
Published: April 2011

The Biomarker-integrated Approaches of Targeted Therapy for Lung Cancer Elimination (BATTLE) trial couples real-time molecular interrogation of cancer specimens with an adaptive Bayesian clinical trial design. Cancer Discovery; 1(1); 14–6. ©2011 AACR.

Commentary on Kim et al., p. 44
Toward Molecular Imaging–Driven Drug Development in Oncology
Authors: de Vries Elisabeth G.E. , Munnink Thijs H. Oude , van Vugt Marcel A.T.M. , Nagengast Wouter B.
Published: April 2011

With current testing strategies, the number of novel targeted anticancer agents will exceed our drug selection capacity. Molecular imaging is a powerful additional tool that can assist us in selecting effective drugs and help patients benefit from targeted agents. Moreover, measurement of the functional effects of such targeted agents could permit dynamic tuning of treatment selection at the earliest time point at which loss of functional effects is observed. Cancer Discovery; 1(1); 25–8. ©2011 AACR.
Macrophage Mal1 Deficiency Suppresses Atherosclerosis in Low-Density Lipoprotein Receptor–Null Mice by Activating Peroxisome Proliferator-Activated Receptor-γ–Regulated Genes
Authors: Babaev Vladimir R. , Runner Robert P. , Fan Daping , Ding Lei , Zhang Youmin , Tao Huan , Erbay Ebru , Görgün Cem Z. , Fazio Sergio , Hotamisligil Gökhan S. , Linton MacRae F.
Published: April 2011

Objective—

The adipocyte/macrophage fatty acid-binding proteins aP2 (FABP4) and Mal1 (FABP5) are intracellular lipid chaperones that modulate systemic glucose metabolism, insulin sensitivity, and atherosclerosis. Combined deficiency of aP2 and Mal1 has been shown to reduce the development of atherosclerosis, but the independent role of macrophage Mal1 expression in atherogenesis remains unclear.

Methods and Results—

We transplanted wild-type (WT), Mal1
−/−
, or aP2
−/−
bone marrow into low-density lipoprotein receptor–null (LDLR
−/−
) mice and fed them a Western diet for 8 weeks. Mal1
−/−
→LDLR
−/−
mice had significantly reduced (36%) atherosclerosis in the proximal aorta compared with control WT→LDLR
−/−
mice. Interestingly, peritoneal macrophages isolated from Mal1-deficient mice displayed increased peroxisome proliferator-activated receptor-γ (PPARγ) activity and upregulation of a PPARγ-related cholesterol trafficking gene, CD36. Mal1
−/−
macrophages showed suppression of inflammatory genes, such as
COX2
and interleukin 6. Mal1
−/−
→LDLR
−/−
mice had significantly decreased macrophage numbers in the aortic atherosclerotic lesions compared with WT→LDLR
−/−
mice, suggesting that monocyte recruitment may be impaired. Indeed, blood monocytes isolated from Mal1
−/−
→LDLR
−/−
mice on a high-fat diet had decreased CC chemokine receptor 2 gene and protein expression levels compared with WT monocytes.

Conclusion—

Taken together, our results demonstrate that Mal1 plays a proatherogenic role by suppressing PPARγ activity, which increases expression of CC chemokine receptor 2 by monocytes, promoting their recruitment to atherosclerotic lesions.
Existence of an Endogenous Circadian Blood Pressure Rhythm in Humans That Peaks in the Evening
Authors: Shea Steven A. , Hilton Michael F. , Hu Kun , Scheer Frank A.J.L.
Published: April 2011

Rationale:

Blood pressure (BP) usually decreases during nocturnal sleep and increases during daytime activities. Whether the endogenous circadian control system contributes to this daily BP variation has not been determined under appropriately controlled conditions.

Objective:

To determine whether there exists an endogenous circadian rhythm of BP in humans.

Methods and Results:

In 28 normotensive adults (16 men), we assessed BP across 3 complementary, multiday, in-laboratory protocols performed in dim light, throughout which behavioral and environmental influences were controlled and/or uniformly distributed across the circadian cycle via: (1) a 38-hour “constant routine,” including continuous wakefulness; (2) a 196-hour “forced desynchrony” with 7 recurring 28-hour sleep/wake cycles; and (3) a 240-hour forced desynchrony with 12 recurring 20-hour sleep/wake cycles. Circadian phases were derived from core body temperature. Each protocol revealed significant circadian rhythms in systolic and diastolic BP, with almost identical rhythm profiles among protocols. The peak-to-trough amplitudes were 3 to 6 mm Hg for systolic BP and 2 to 3 mm Hg for diastolic BP (always
P
<0.05). All 6 peaks (systolic and diastolic BP in 3 protocols) occurred at a circadian phase corresponding to ≈9:00
pm
(ie, the biological evening). Based on substantial phase differences among circadian rhythms of BP and other variables, the rhythm in BP appeared to be unrelated to circadian rhythms in cortisol, catecholamines, cardiac vagal modulation, heart rate, or urine flow.

Conclusions:

There exists a robust endogenous circadian rhythm in BP. The highest BP occurred at the circadian time corresponding to ≈9:00
pm
, suggesting that the endogenous BP rhythm is unlikely to underlie the well-documented morning peak in adverse cardiovascular events.
Anti-high Mobility Group Box-1 Monoclonal Antibody Protects the Blood–Brain Barrier From Ischemia-Induced Disruption in Rats
Authors: Zhang Jiyong , Takahashi Hideo K. , Liu Keyue , Wake Hidenori , Liu Rui , Maruo Tomoko , Date Isao , Yoshino Tadashi , Ohtsuka Aiji , Mori Shuji , Nishibori Masahiro
Published: April 2011

Background and Purpose—

High mobility group box-1 (HMGB1) exhibits inflammatory cytokine-like activity in the extracellular space. We previously demonstrated that intravenous injection of anti-HMGB1 monoclonal antibody (mAb) remarkably ameliorated brain infarction induced by middle cerebral artery occlusion in rats. In the present study, we focused on the protective effects of the mAb on the marked translocation of HMGB1 in the brain, the disruption of the blood–brain barrier (BBB), and the resultant brain edema.

Methods—

Middle cerebral artery occlusion in the rat was used as the ischemia model. Rats were treated with anti-HMGB1 mAb or control IgG intravenously. BBB permeability was measured by MRI. Ultrastructure of the BBB unit was observed by transmission electron microscope. The in vitro BBB system was used to study the direct effects of HMGB1 in BBB components.

Results—

HMGB1 was time-dependently translocated and released from neurons in the ischemic rat brain. The mAb reduced the edematous area on T2-weighted MRI. Transmission electron microscope observation revealed that the mAb strongly inhibited astrocyte end feet swelling, the end feet detachment from the basement membrane, and the opening of the tight junction between endothelial cells. In the in vitro reconstituted BBB system, recombinant HMGB1 increased the permeability of the BBB with morphological changes in endothelial cells and pericytes, which were inhibited by the mAb. Moreover, the anti-HMGB1 mAb facilitated the clearance of serum HMGB1.

Conclusions—

These results indicated that the anti-HMGB1 mAb could be an effective therapy for brain ischemia by inhibiting the development of brain edema through the protection of the BBB and the efficient clearance of circulating HMGB1.
C-Reactive Protein Level Measurement Improves Mortality Prediction When Added to the Spontaneous Intracerebral Hemorrhage Score
Authors: Di Napoli Mario , Godoy Daniel Agustin , Campi Veronica , del Valle Marta , Piñero Gustavo , Mirofsky Matias , Popa-Wagner Aurel , Masotti Luca , Papa Francesca , Rabinstein Alejandro A.
Published: April 2011

Background and Purpose—

Hyperglycemia and inflammation are involved in the progression of spontaneous intracerebral hemorrhage (sICH)-induced brain injury, but their role in predicting clinical outcome is not clear. We sought to determine whether elevation of white blood cell count (WBC), C-reactive protein (CRP), and blood glucose (BG) concentration at presentation prognosticate poor outcome in sICH patients.

Methods—

Between November 1, 2005 and October 31, 2009, 210 patients admitted to 2 intensive care units were prospectively consecutively evaluated after exclusion of patients with underlying inflammatory conditions. WBC, CRP, and BG were measured and ICH scores were calculated on first evaluation. Primary outcome was 30-day mortality. Secondary outcome was 30-day functional outcome using the Glasgow Outcome scale.

Results—

The median CRP concentration was 7.85 mg/L (interquartile range, 4.0–12.0 mg/L), median WBC count was 8.05×10
9
/L (interquartile range, 6.45–9.9×10
9
/L) and median glucose concentration was 7.66 mmol/L (interquartile range, 6.11–10.83 mmol/L). At 30 days, 63 patients (30%) were dead and 101 (48.1%) had poor outcome (Glasgow Outcome scale score, 1–3). Higher WBC (
P
<0.001), CRP (
P
<0.05), and BG (
P
<0.001) were associated with mortality on univariate analyses, but only CRP remained associated with mortality (
P
<0.005) after adjustment for multiple confounders. CRP improved mortality prediction when added to the ICH score. None of the markers tested had significant associations with functional outcome.

Conclusions—

Higher WBC, CRP, and BG are associated with increased mortality in sICH patients. Only CRP elevation portends higher risk of death independently of other indicators of sICH severity.
Virtual Reality in Stroke Rehabilitation
Authors: Saposnik Gustavo , Levin Mindy ,   for the Stroke Outcome Research Canada (SORCan) Working Group
Published: April 2011

Background and Purpose—

Approximately two thirds of stroke survivors continue to experience motor deficits of the arm resulting in diminished quality of life. Conventional rehabilitation provides modest and sometimes delayed effects. Virtual reality (VR) technology is a novel adjunctive therapy that could be applied in neurorehabilitation. We performed a meta-analysis to determine the added benefit of VR technology on arm motor recovery after stroke.

Methods—

We searched Medline, EMBASE, and Cochrane literature from 1966 to July 2010 with the terms “stroke,” “virtual reality,” and “upper arm/extremity.” We evaluated the effect of VR on motor function improvement after stroke.

Results—

From the 35 studies identified, 12 met the inclusion/exclusion criteria totaling 195 participants. Among them, there were 5 randomized clinical trials and 7 observational studies with a pre-/postintervention design. Interventions were delivered within 4 to 6 weeks in 9 of the studies and within 2 to 3 weeks in the remaining 3. Eleven of 12 studies showed a significant benefit toward VR for the selected outcomes. In the pooled analysis of all 5 randomized controlled trials, the effect of VR on motor impairment (Fugl-Meyer) was OR=4.89 (95% CI, 1.31 to 18.3). No significant difference was observed for Box and Block Test or motor function. Among observational studies, there was a 14.7% (95% CI, 8.7%–23.6%) improvement in motor impairment and a 20.1% (95% CI, 11.0%–33.8%) improvement in motor function after VR.

Conclusions—

VR and video game applications are novel and potentially useful technologies that can be combined with conventional rehabilitation for upper arm improvement after stroke.
The acceptability of e-technology to monitor and assess patient symptoms following palliative radiotherapy for lung cancer
Authors: Cox Anna , Illsley Marianne , Knibb Wendy , Lucas Caroline , O’Driscoll Michael , Potter Claire , Flowerday Adrian , Faithfull Sara
Published: April 2011

E-technology is increasingly used in oncology to obtain self-reported symptom assessment information from patients, although its potential to provide a clinical monitoring tool in palliative care is relatively unexplored in the UK. This study aimed to evaluate the support provided to lung cancer patients post palliative radiotherapy using a computerized assessment tool and to determine the clinical acceptability of the tool in a palliative care setting. However, of the 17 clinicians identified as managing patients who met the initial eligibility criteria for the study, only one clinician gave approval for their patient to be contacted regarding participation, therefore the benefits of this novel technology could not be assessed. Thirteen key clinicians from the centres involved in the study were subsequently interviewed. They acknowledged potential benefits of incorporating computerized patient assessment from both a patient and practice perspective, but emphasized the importance of clinical intuition over standardized assessment. Although clinicians were positive about palliative care patients participating in research, they felt that this population of patients were normally too old, with too rapidly deteriorating a condition to participate in a study using e-technology. In order to encourage acceptance of e-technology within palliative care, emphasis is needed on actively promoting the contribution of technologies with the potential to improve patient outcomes and the patient experience.
Amount of Meniscal Resection after Failed Meniscal Repair
Authors: Pujol Nicolas , Barbier Olivier , Boisrenoult Philippe , Beaufils Philippe
Published: April 2011

Background

The failure rate after arthroscopic meniscal repair ranges from 5% to 43.5% (mean, 15%) in the literature. But little is known about the amount of meniscal tissue removed after failed meniscal repair.

Hypothesis

The volume of subsequent meniscectomy after failed meniscal repair is not increased when compared with the volume of meniscectomy that would have been performed if not initially repaired.

Study Design

Case series; Level of evidence, 4.

Methods

From January 2000 to December 2009, 295 knees underwent arthroscopic meniscal repair for unstable peripheral vertical tears. When present (219 cases), all anterior cruciate ligament (ACL) tears underwent reconstruction. Patients with multiple ligament injuries and posterior cruciate ligament injuries were excluded from the analysis. Thirty-two medial and 5 lateral menisci underwent subsequent meniscectomy after failed repair at a mean of 26 months postoperatively (range, 3-114 months). Five parameters were specifically evaluated: the amount of meniscectomy related to the initial tear, the ACL status, the appearance of chondral lesions, the time from the initial injury to meniscal repair, and the time from repair to meniscectomy.

Results

The posterior segment of the meniscus was involved in all tears and retears. Among failures, resection of the meniscal segments primarily repaired occurred for 17 medial and 2 lateral meniscal tears (52%); the tear extended in 5 cases (all medial menisci), and healing of some repaired segments led to a partial resection of the initial lesion in 35% of cases (10 medial menisci, 3 lateral menisci). The time from injury to meniscal repair was correlated with an increasing volume of meniscus removed ( P < .05) and with the presence of stage 2 or 3 chondral lesions at revision ( P < .03). All knees with extended tears (5 cases) and/or with significant chondral degeneration (8 cases) occurred in ACL-reconstructed knees. Among them, 50% (6 of 12) of ACL-reconstructed knees were ACL deficient.

Conclusion

There are few detrimental effects when repairing a repairable meniscal lesion, even if it fails. The amount of meniscectomy is rarely increased when compared with the initial lesion. This study supports the hypothesis that the meniscus can be partially saved and that a risk of a partial failure should be taken when possible.