bluuebunny/crossref_metadata_2025 huggingface dataset:
Evolving product form designs using parametric shape grammars integrated with genetic programming
Authors: Lee Ho Cheong , Tang Ming Xi
Published: November 2008

The two critical issues related to product design exploration are addressed: the balance between stylistic consistency and innovation, and the control of design process under a great diversity of requirements. To address these two issues, the view of understanding product design exploration is first sought. In this view, the exploration of designs is not only categorized as a problem-solving activity but also as a problem-finding activity. A computational framework is developed based on this view, and it encompasses the belief that these two activities go hand in hand to accomplish the design tasks in an interactive design environment. The framework adopts an integration approach of two key computational techniques, shape grammars and evolutionary computing, for addressing the above two critical issues. For the issues of stylistic consistency, this paper focuses on the computational techniques in balancing the conflicts of stylistic consistency and innovation with shape grammars. For the issues of controlling design process, the practical concerns of monitoring the design process through various activities starting from the preparation works to the implementation of shape grammars have been emphasized in the development of this framework. To evaluate the effectiveness of the framework, the experiments have been set up to reflect the practical situations with which the designers have to deal. The system generates a number of models from scratch with numerical analysis that can be evaluated effectively by the designers. This reduces the designers' time and allows the designers to concentrate their efforts on performing higher level of design activities such as evaluation of designs and making design decisions.
A pilot study of transformation, attributed meanings to the illness, and spiritual well-being for terminally ill cancer patients
Authors: Ando Michiyo , Morita Tatsuya , Lee Virginia , Okamoto Takuya
Published: November 2008

Objective:

The present study investigated what types of transformation terminally ill cancer patients experienced from diagnosis until the terminal stage, what meanings terminally ill cancer patients attributed to their illness, and whether or not those who attributed positive meaning to their illness achieved high levels of spiritual well-being as a preliminary study.

Method:

Ten terminally ill cancer patients in the hospice wards of two general hospitals participated. A clinical psychologist conducted a semistructured interview with the patients individually for about 60 min. Patients completed the FACIT-Sp and HADS before the interview and talked about the meanings of cancer experience. The contents of the interviews were analyzed qualitatively. Patients were separated into high and low levels of spiritual-well being by the median of FACIT-Sp scores.

Results:

Three types of transformation were extracted: “group with peaceful mind,” “group with both positive attitude and uneasy feeling,” and “groups with uneasy feeling.” As attributed meanings to the illness, five categories were extracted: “positive meaning,” “natural acceptance,” “negative acceptance,” “search for meaning,” and “regret and sorrow.” Patients in the high level spiritual well-being group attributed the meaning of illness to “positive meaning” and “natural acceptance,” and those in the low level spiritual well-being group attributed it to “regret and sorrow” and “search for meaning.”

Significance of results:

Some Japanese terminally ill cancer patients experienced positive transformation, and patients who attributed “positive meaning” and “natural acceptance” to their illness experience achieved high levels of spiritual well-being.
Palliative care at home: Carers and medication management
Authors: Anderson Barbara A. , Kralik Debbie
Published: November 2008

Objective:

The decision to receive palliative care at home brings with it the complexity of managing a medication regime. Effective symptom control is often directly linked to medication management and relies on access to medications at all times. In home-based palliative care practice, polypropylene syringes of medications may be drawn up and left in clients' domestic refrigerators for subcutaneous administration by carers to provide immediate relief for symptoms such as pain and nausea. However, although there has been some discussion in the literature about the need for ready access to medications for symptom control of clients receiving care in the community, the feasibility of this practice has received scant attention. The aim of this article is to present the carers' experiences of administering medications in this manner.

Methods:

Semistructured interviews with 14 carers, who were administering medication in a home-based palliative care setting, were analyzed using qualitative methods to develop meaning units and themes.

Results:

Interviews revealed that this practice was highly valued. The carers willingly assumed the responsibility of medication administration, as it allowed the clients to remain at home where they desired to be. They could provide immediate symptom relief, which was of utmost importance to both the client and carer. The carers were empowered in their caring role, being able to participate in the care provided, rather than standing on the sidelines as helpless observers. Carers acknowledged the security and ethical issues associated with the presence of certain medications in the home and valued the 24-h telephone support that was available to them. After clients had died, the carers reflected on their involvement in care and felt a sense of pride and achievement from administering medications in this way because they had been able to care for their loved ones at home and fulfill their wish to die there.

Significance of results:

These interviews confirm the feasibility of this practice, which is a component of quality end-of-life care.
Barriers to hospice enrollment among lung cancer patients: A survey of family members and physicians
Authors: Ford Dee W. , Nietert Paul J. , Zapka Jane , Zoller James S. , Silvestri Gerard A.
Published: November 2008

Objective:

Most patients diagnosed with lung cancer present with advanced stage disease and have a poor chance of long-term survival. Despite the advantages of hospice care for lung cancer patients, many are enrolled late in the course of their illness or not at all. We sought to identify reasons for this pattern.

Method:

A list of perceived barriers to hospice enrollment was generated and used to create two self-administered surveys, one for physicians and one for caregivers. After focus group testing, the finalized instruments were mailed to physicians in South Carolina and to caregivers of lung cancer patients who died under hospice care with a local hospice between 2000 and 2004.

Results:

Fifty-three caregivers and 273 physicians responded to the survey. From the caregivers' perspectives, leading reasons for deferred hospice enrollment included patients' unanticipated rapid transition from well to sick and a belief that hospice means giving up hope. From the physicians' perspectives, impediments to earlier hospice enrollment included patients and caregivers overestimating survival from lung cancer and an (incorrect) assumption that patients need to be “DNR/DNI” prior to hospice enrollment.

Significance of results:

Lung cancer patients may benefit from earlier introduction to the concepts of hospice care and more education regarding prognosis so that an easier transition in goals of care could be achieved. A smaller proportion of lung cancer patients may benefit from earlier hospice enrollment.
Who Regulates Phones, Television, and the Internet? What Makes a Communications Regulator Independent and Why It Matters
Authors: Wu Irene
Published: November 2008

More political scientists should engage in the debates surrounding regulation of communications networks, the infrastructure on which telecom, media, and Internet services ride. In 1990 there were 14 communications regulators worldwide, by 2007 there were 148. To fulfill World Trade Organization Agreement on Basic Telecommunications commitments, many countries aim to create regulatory agencies that are “independent.” What characterizes independence? Regulators are embedded in a political context that includes three main constituencies : other government institutions, industry, and consumers. Independent regulators are able to take action autonomously from other government institutions and industry while serving as advocates for consumers. In a survey of 18 countries, several traits emerge; a leader who cannot be dismissed arbitrarily, regulatory authority clearly distinct from policymaking, independent funding, minimal staff exchange between regulator and regulated firm, and dedicated support for consumers. It is usually easier for a regulator to be independent if operators are privatized. In a study of 4 countries, independent regulators follow decision-making procedures that give the public notice about proposed rule changes, opportunities to provide comments, and final decisions with explanation. Also, independent regulators have gift, conflict of interest, and post-employment rules, which set ethical standards and expectations for staff.
Critical Dialogue
Authors: Smith Anna Marie
Published: November 2008

In her timely and provocative book, Kathleen Arnold examines the super-exploitation and disenfranchisement of the “new working class”—low-income immigrants, African Americans, and women workers—and utilizes these phenomena as a catalyst for sharpening our critical understanding of American governance in our globalizing conditions. She contends that the neoliberal state is deploying deregulation and massive policing interventions simultaneously. The latter range from the exposure of welfare mothers to the rigors of workfare to the war on drugs, post-9/11 domestic security operations, mean-spirited attacks on the homeless, and the crackdown on illegal immigration. Arnold proposes a sobering diagnosis that is loosely based upon Giorgio Agamben's theory of bare life: As the state operates outside the law on a frequent and even systematic basis to reduce these target groups to a subhuman status, we are witnessing the triumph of prerogative power in American society today.
Response to Anna Marie Smith's review of America's New Working Class
Authors: Arnold Kathleen R.
Published: November 2008

Anna Marie Smith and I have similar concerns about the poor, racism and sexism. Yet we view political theory in different ways. Smith has focused on one set of programs and gives the reader a richly detailed view of recent welfare laws. In contrast, I have tried to do something very different. First, I use Giorgio Agamben's ideas as a foil, drawing upon Hannah Arendt and Michel Foucault to supplement this reading, and I investigate the ideas of John Locke (rather than Thomas Hobbes) to understand sovereignty today. By looking at Locke, we can understand how representative government based on the rule of law and equality can coexist with prerogative power used systematically and domestically. Instead of a top-down view of power, I argue that modern power is characterized by the dispersal of sovereignty and, importantly, prerogative power (the legal suspension of the law). Thus, even as national borders have become more open (both with economic globalization and post-Clausewitzean forms of war), state sovereignty has not necessarily declined. In fact, the use of prerogative power increasingly characterizes late-modern power even as neoliberal rhetoric gives the opposite impression.
Dynamics of carbon, biomass, and structure in two Amazonian forests
Authors: Pyle Elizabeth Hammond , Santoni Gregory W. , Nascimento Henrique E. M. , Hutyra Lucy R. , Vieira Simone , Curran Daniel J. , van Haren Joost , Saleska Scott R. , Chow V. Y. , Carmago Plinio B. , Laurance William F. , Wofsy Steven C.
Published: November 2008

Amazon forests are potentially globally significant sources or sinks for atmospheric carbon dioxide. In this study, we characterize the spatial trends in carbon storage and fluxes in both live and dead biomass (necromass) in two Amazonian forests, the Biological Dynamic of Forest Fragments Project (BDFFP), near Manaus, Amazonas, and the Tapajós National Forest (TNF) near Santarém, Pará. We assessed coarse woody debris (CWD) stocks, tree growth, mortality, and recruitment in ground‐based plots distributed across the terra firme forest at both sites. Carbon dynamics were similar within each site, but differed significantly between the sites. The BDFFP and the TNF held comparable live biomass (167 ± 7.6 MgC·ha−1 versus 149 ± 6.0 MgC·ha−1, respectively), but stocks of CWD were 2.5 times larger at TNF (16.2 ± 1.5 MgC·ha−1 at BDFFP, versus 40.1 ± 3.9 MgC·ha−1 at TNF). A model of current forest dynamics suggests that the BDFFP was close to carbon balance, and its size class structure approximated a steady state. The TNF, by contrast, showed rapid carbon accrual to live biomass (3.24 ± 0.22 MgC·ha−1·a−1 in TNF, 2.59 ± 0.16 MgC·ha−1·a−1 in BDFFP), which was more than offset by losses from large stocks of CWD, as well as ongoing shifts of biomass among size classes. This pattern in the TNF suggests recovery from a significant disturbance. The net loss of carbon from the TNF will likely last 10–15 years after the initial disturbance (controlled by the rate of decay of coarse woody debris), followed by uptake of carbon as the forest size class structure and composition continue to shift. The frequency and longevity of forests showing such disequilibruim dynamics within the larger matrix of the Amazon remains an essential question to understanding Amazonian carbon balance.
Aerosol characterization during the summer monsoon period over a tropical coastal Indian station, Visakhapatnam
Authors: Madhavan B. L. , Niranjan K. , Sreekanth V. , Sarin M. M. , Sudheer A. K.
Published: November 2008

Columnar optical depth and near‐surface mass concentration of aerosols over Visakhapatnam, an urban location along the east coast of India during the summer monsoon period (May–August 2005), were measured simultaneously along with chemical sampling for water‐soluble ionic species (NH4+, Na+, K+, Mg2+, Ca2+, Cl−, NO3−, SO42−, and HCO3−). The mean aerosol optical depth (AOD) (0.5 μm) and Angstrom parameters (α, β) during this period were obtained as 0.72 ± 0.39 and 0.88 ± 0.39, 0.48 ± 0.36, respectively. The total surface aerosol mass concentration varied from 95 to 128 (μg/m3), out of which coarse mode dominated by 45%. While Cl−, Na+, K+, and Mg2+ (sea salts) contributed nearly 56%, SO42− and NO3− (anthropogenic constituents) contributed 33% in surface aerosol constituents. During this period, high spectral variability in AOD, negative curvature of second‐order Angstrom coefficient (α1), abundance of columnar submicron aerosols, role of air mass trajectories as tracers of long‐range transport, cation deficiency, and sea‐salt dependence on wind speed are some of the observations over Visakhapatnam. The synergy of the results from these complementary measurements can be reflected while computing the aerosol radiative forcing.
The role of microorganisms in coral bleaching
Authors: Rosenberg Eugene , Kushmaro Ariel , Kramarsky-Winter Esti , Banin Ehud , Yossi Loya
Published: November 2008

Coral bleaching is the disruption of the symbiosis between the coral host and its endosymbiotic algae. The prevalence and severity of the disease have been correlated with high seawater temperature. During the last decade, the major hypothesis to explain coral bleaching is that high water temperatures cause irreversible damage to the symbiotic algae resulting in loss of pigment and/or algae from the holobiont. Here, we discuss the evidence for an alternative but not mutually exclusive concept, the microbial hypothesis of coral bleaching.
N‐6 From Different Sources Protect From Metabolic Alterations to Obese Patients: A Factor Analysis
Authors: Hernández‐Morante Juan J. , Larqué Elvira , Luján Juan A. , Zamora Salvador , Garaulet Marta
Published: November 2008

First, to analyze the interactions among fatty acids (FAs) from diet, plasma and subcutaneous and visceral adipose tissue (AT), and second, the relationship among FAs from these different sources and obesity‐related alterations in extreme obesity. We studied 20 extreme obese subjects. A food‐frequency questionnaire was used to determine the FA intakes. Serum and AT (subcutaneous and visceral) FA concentrations were determined by gas chromatography. Cardiometabolic risk parameters were assessed. Principal factor analysis was performed to define specific FA factors in the metabolic alterations. We found important associations among diet, plasma, and AT FA and cardiometabolic parameters. In this regard, it is interesting to highlight the negative associations between plasma cholesterol and dietary n‐3 FA. In the subcutaneous depot, as occurred in plasma, n‐6 and polyunsaturated FAs (PUFA) were negatively associated with triacylglycerols (TGs). Factor analysis revealed TGs as the unique cardiovascular risk parameter appearing in the first factor (F1), together with n‐6 (load factor = 0.94) and PUFA (0.91). Besides, n‐3 from diet and plasma appeared in the third factor inversely related to cholesterol, low‐density lipoprotein cholesterol (LDL‐c), and insulin. In an opposite way, dietary and AT trans FAs and saturated FA (SFA) were associated to an increase of the metabolic risk. We have shown, for the first time, the importance of n‐6 and PUFAs composition as protective factors against metabolic alterations in extreme obese subjects. These findings support current dietary recommendations to increase PUFA intakes and restrict saturated and trans FA intakes even in extreme obesity.
Insulin stimulates the phosphorylation of the exocyst protein Sec8 in adipocytes
Authors: Lyons Patrick D. , Peck Grantley R. , Kettenbach Arminja N. , Gerber Scott A. , Roudaia Liya , Lienhard Gustav E.
Published: November 2008

The signal transduction pathway leading from the insulin receptor to stimulate the fusion of vesicles containing the glucose transporter GLUT4 with the plasma membrane in adipocytes and muscle cells is not completely understood. Current evidence suggests that in addition to the Rab GTPase-activating protein AS160, at least one other substrate of Akt (also called protein kinase B), which is as yet unidentified, is required. Sec8 is a component of the exocyst complex that has been previously implicated in GLUT4 trafficking. In the present study, we report that insulin stimulates the phosphorylation of Sec8 on Ser-32 in 3T3-L1 adipocytes. On the basis of the sequence around Ser-32 and the finding that phosphorylation is inhibited by the PI3K (phosphoinositide 3-kinase) inhibitor wortmannin, it is likely that Akt is the kinase for Ser-32. We examined the possible role of Ser-32 phosphorylation in the insulin-stimulated trafficking of GLUT4, as well as the TfR (transferrin receptor), to the plasma membrane by determining the effects of overexpression of the non-phosphorylatable S32A mutant of Sec8 and the phosphomimetic S32E mutant of Sec8. Substantial overexpression of both mutants had no effect on the amount of GLUT4 or TfR at the cell surface in either the untreated or insulin-treated states. These results indicate that insulin-stimulated phosphorylation of Sec8 is not part of the mechanism by which insulin enhances the fusion of vesicles with the plasma membrane.
Laser generation of gas bubbles: Photoacoustic and photothermal effects recorded in transient grating experiments
Authors: Frez Clifford , Diebold Gerald J.
Published: November 2008

Absorption of high power laser radiation by colloidal suspensions or solutions containing photoreactive chemicals can result in bubble production. Here, transient grating experiments are reported where picosecond and nanosecond lasers are used to initiate photoinduced processes that lead to bubble formation. Irradiation of colloidal Pt suspensions is found to produce water vapor bubbles that condense back to liquid on a nanosecond time scale. Laser irradiation of Pt suspensions supersaturated with CO2 liberates dissolved gas to produce bubbles at the sites of the colloidal particles. Laser induced chemical reactions that produce bubbles are found in suspensions of particulate C in water, and in the sensitized decarboxylation of oxalic acid. Theory based on linear acoustics as well as the Rayleigh–Plesset equation is given for description of the bubble motion.
Property modifications of nanoporous pSiCOH dielectrics to enhance resistance to plasma-induced damage
Authors: Ryan E. Todd , Gates Stephen M. , Grill Alfred , Molis Steven , Flaitz Philip , Arnold John , Sankarapandian Muthumanickam , Cohen Stephan A. , Ostrovski Yuri , Dimitrakopoulos Christos
Published: November 2008

The resistance to plasma-induced damage of various nanoporous, ultra low-κ porous SiCOH films used as interconnect dielectric materials in integrated circuits was studied. These films are susceptible to damage by plasma processes used during nanofabrication. The dielectric constants and chemical compositions of four dielectric films were correlated with measured amounts of plasma damage. Films deposited with higher carbon content in the form of Si–CH3 and Si(CH3)2 bonding exhibited less plasma damage than similar films with lower carbon content.
Characteristics of the transition to turbulence in superfluid He4 at low temperatures
Authors: Sheshin G. A. , Zadorozhko A. A. , Rudavskiĭ É. Ya. , Chagovets V. K. , Skrbek L. , Blazhkova M.
Published: November 2008

A piezoquartz oscillator (tuning fork) immersed in liquid is used to study the kinetic and dissipative processes in He II experimentally. The electrical response of the tuning fork near its resonance frequency is measured with different exciting voltages at temperatures ranging from 0.1Kto4.2K. The measured values of the half-width of the resonance curves made it possible to determine the viscosity of the normal component of He II in a wide temperature range. A maximum of the effective viscosity is found at temperature ∼0.5K; this maximum is due to a transition from the hydrodynamic to the ballistic regime in the phonon gas in He II. It is established that for low velocities of oscillation of the tuning fork the velocities are a linear function of the excitation force; this corresponds to laminar flow of the liquid in the boundary layer near the oscillating surface. The main dissipative process is associated with the viscosity of the normal component. The thickness of the boundary layer near the surface of the oscillating tuning fork is estimated. Kinks attesting to a transition to nonlinear flow are found in the dependence of the electric response on the excitation voltage for high velocities of the tuning fork. At low temperatures this regime is accompanied by the appearance of flat sections near the maximum in the resonance curves. This behavior can be explained by a transition from laminar to turbulent flow of the liquid, which likewise is accompanied by the appearance of additional dissipation due to the creation of quantum vortices. The critical velocity of the transition to the turbulent regime, whose temperature dependence qualitatively agrees with measurements performed previously using oscillating bodies of a different shape, is determined.
Possibility of s-wave pairing in heavily Zn-doped YBa2Cu3O7−δ based on a magnetic field effect on the Andreev reflection spectra
Authors: Akimenko A. I. , Gudimenko V. A.
Published: November 2008

When the dx2−y2-wave pairing is suppressed by Zn doping in YBa2Cu3O7−δ, some of the Andreev reflection spectra are found to be similar to the s-wave spectra of conventional superconductors. The energy gap is rather reproducible (2.3–3.0meV). It is suppressed by low magnetic field (HcPC=120–270mT), in great contrast to the d-wave spectra (HcPC>3T) for a similar order of magnitude of the gap. We suppose that the s-wave pairing occurs near the Zn impurities.
Magnetic properties of p-La0.78Mn0.99O3.5 and p-La0.80Mn1.04O3.5 obtained at high pressure 7.5GPa
Authors: Rykova A. I. , Chernyĭ A. S. , Khats’ko E. N. , Shevchenko A. D. , Uvarov V. N.
Published: November 2008

Structural and magnetic studies of nanocomposite samples of lanthanum manganite p-La0.78Mn0.99O3+δ and p-La0.80Mn1.04O3+δ with excess oxygen (δ=0.5) have been performed. The samples were obtained at high pressure (7.5GPa). X-Ray studies showed that the samples consist of a single phase and possess perovskite cubic structure. The lattice parameters were determined. Scanning atomic-force microscopy was used to find the characteristic sizes of the nanograins (70nm). Temperature studies of the magnetic susceptibility showed that at temperature of the order of 260K both samples pass into the ferromagnetic state. Above TC the samples exhibited paramagnetic behavior and follow the Curie–Weiss law χ=C∕(T−θ) with a positive Curie–Weiss constant θ≈280±1K for both samples. Below TC the nanocomposites exhibited spin-glass behavior. However, the field dependences of the magnetization of the samples differed substantially. The saturation fields for p-La0.78Mn0.99O3.5 and p-La0.80Mn1.04O3.5 differed by a factor of 4, and a strong temperature dependence of the magnetic rigidity was observed for both compounds. The effective magnetic moments for p-La0.78Mn0.99O3.5 and p-La0.80Mn1.04O3.5 are 0.84μB and 3.24μB.
Electron diffraction analysis of the FCC–HCP transition in argon clusters with a change in cluster size
Authors: Danil’chenko A. G. , Kovalenko S. I. , Samovarov V. N.
Published: November 2008

A transition from FCC to mixed FCC–HCP structure as a function of the cluster size is followed for the first time in free crystals formed in supersonic argon streams. It is established that FCC reflections appear and their intensity sharply increases for linear size of the aggregations of about 110Å. As cluster size increases above this value, the FCC reflections become weaker. The transition is preceded by a special structural state of the clusters where there is a substantial number of randomly arranged close-packed atomic layers. Such a transition has been observed previously in bulk samples of solid argon under compression to pressure of approximately 50GPa. In clusters where such a high pressure is not reached, the appearance of a disordered close-packed structure followed by the appearance of FCC domains is probably due to the mechanisms of aggregation growth in supersonic streams.
Computational model for the formation of uniform silver spheres by aggregation of nanosize precursors
Authors: Robb Daniel T. , Halaciuga Ionel , Privman Vladimir , Goia Dan V.
Published: November 2008

We present results of computational modeling of the formation of uniform spherical silver particles prepared by rapid mixing of ascorbic acid and silver-amine complex solutions in the absence of a dispersing agent. Using an accelerated integration scheme to speed up the calculation of particle size distributions in the latter stages, we find that the recently reported experimental results—some of which are summarized here—can be modeled effectively by the two-stage formation mechanism used previously to model the preparation of uniform gold spheres. We treat both the equilibrium concentration of silver atoms and the surface tension of silver precursor nanocrystals as free parameters, and find that the experimental reaction time scale is fit by a narrow region of this two-parameter space. The kinetic parameter required to quantitatively match the final particle size is found to be very close to that used previously in modeling the formation of gold particles, suggesting that similar kinetics governs the aggregation process and providing evidence that the two-stage model of burst nucleation of nanocrystalline precursors followed by their aggregation to form the final colloids can be applied to systems both with and without dispersing agents. The model also reproduced semiquantitatively the effects of solvent viscosity and temperature on the particle preparation.
PolLux: A new facility for soft x-ray spectromicroscopy at the Swiss Light Source
Authors: Raabe J. , Tzvetkov G. , Flechsig U. , Böge M. , Jaggi A. , Sarafimov B. , Vernooij M. G. C. , Huthwelker T. , Ade H. , Kilcoyne D. , Tyliszczak T. , Fink R. H. , Quitmann C.
Published: November 2008

We report on the successful installation and operation of a scanning transmission x-ray microspectroscope (STXM) at the PolLux facility at the Swiss Light Source. This integration of an advanced STXM with improved sample handling capabilities and a novel beamline provides unique capabilities. PolLux uses linearly or circularly polarized x-rays from a bending magnet with an extended photon energy range (200–1400 eV). It is therefore well suited to determine a sample’s quantitative chemical composition, molecular orientation, or thickness of organic as well as condensed matter materials. The local magnetic state of magnetic thin films is accessible through fast helicity switching by steering the electron beam off axis through the bending magnet. Ex vacuo girder movers allow fast and highly reproducible (<1 μm) alignment of the instrument with respect to the photon beam. The present spatial resolution is ∼20 nm, limited by the zone plates utilized. The instrument has the stability and positional resolution to operate with much higher resolution optics as it becomes available. In addition to characterization experiments, we present several typical examples from materials research and environmental science to exemplify the capabilities.
Studies on stability in three-layer Hele-Shaw flows
Authors: Daripa Prabir
Published: November 2008

We consider a setup in a Hele-Shaw cell where a fluid of constant viscosity μl occupying a near-half-plane pushes a fluid of constant viscosity μ>μl occupying a layer of length L which in turn pushes another fluid of constant viscosity μr>μ occupying the right half-plane. The fluid upstream has a velocity U. Careful analysis of the dispersion relation arising from linear stability of the three-layer Hele-Shaw flow problem leads to the following specific analytical results all of which are strikingly independent of the length (L) of the middle layer: (i) a necessary and sufficient condition for modal instability; (ii) a critical viscosity of the middle layer that gives the shortest bandwidth of unstable waves; and (iii) a strict upper bound on the growth rate of instabilities, meaning that this upper bound is never reached and hence this upper bound can be improved upon. Results based on exact growth rates are presented which provides some insight into the instability transfer mechanism between interfaces as the parameters of the problem are varied. Numerical evidence that supports the effectiveness of the upper bound is also presented.
Microwave-excited atmospheric-pressure plasma jets using a microstrip line
Authors: Kim Jaeho , Katsurai Makoto , Kim Dongmin , Ohsaki Hyroyuki
Published: November 2008

We report a 2.45GHz microwave-excited atmospheric-pressure plasma jet (MW-APPJ) device using a microstrip line for materials processing. A three-dimensional simulation based on the finite difference time domain method revealed that the configuration of the MW-APPJ device results in a strong concentration of electric fields at the gas nozzle. Argon plasmas were generated at the nozzle and were blown into ambient air with the maximum length of 5mm at a microwave power of 40W. The rotational temperatures of molecular nitrogen in the downstream of the plasma jets, measured by optical emission spectroscopy, were 1720to900K for gas flow rates from 0.5to3.5l∕min, indicating that the jets were nonthermal plasmas. This MW-APPJ device will provide a large-area APPJ for materials processing depending on the configuration of the nozzle array and microstrip lines.
Composite structure and size effect of barium titanate nanoparticles
Authors: Hoshina Takuya , Wada Satoshi , Kuroiwa Yoshihiro , Tsurumi Takaaki
Published: November 2008

Nanostructures of barium titanate (BaTiO3) nanoparticles were analyzed using a composite structure model. It was found that BaTiO3 nanoparticles had a composite structure consisting of (i) inner tetragonal core, (ii) gradient lattice strain layer (GLSL), and (iii) surface cubic layer. The crystal structure of each region did not depend on particle size while the volume fraction of the GLSL and the surface cubic layer increased with decreasing the particle size. These results suggested that the size effect of BaTiO3 nanoparticles originated from the composite structure.
Intensity detection of terahertz quantum cascade laser radiation using electro-optic sampling
Authors: Rungsawang R. , Marshall O. , Freeman J. R. , Beere H. E. , Malik S. , Alton J. , Barbieri S. , Ritchie D. A.
Published: November 2008

We demonstrate intensity detection of terahertz radiation from a 2 THz quantum cascade laser with nonsynchronized electro-optic (EO) sampling under crossed polarizers. The detection sensitivity is limited by the residual birefringence of the EO detection crystal. With 100 fs fiber laser pulses and a CdTe EO crystal, terahertz radiation with power less than 100 μW was detected. A femtosecond gating pulse provides an ultrashort detection response that is potentially very useful for analyzing temporal performance of short pulsed radiation or observing fast phenomena probed by terahertz pulses.
Deletion of the chloride transporter Slc26a9 causes loss of tubulovesicles in parietal cells and impairs acid secretion in the stomach
Authors: Xu Jie , Song Penghong , Miller Marian L. , Borgese Frank , Barone Sharon , Riederer Brigitte , Wang Zhaohui , Alper Seth L. , Forte John G. , Shull Gary E. , Ehrenfeld Jordi , Seidler Ursula , Soleimani Manoocher
Published: November 2008

Slc26a9 is a recently identified anion transporter that is abundantly expressed in gastric epithelial cells. To study its role in stomach physiology, gene targeting was used to prepare mice lacking Slc26a9. Homozygous mutant (Slc26a9−/−) mice appeared healthy and displayed normal growth. Slc26a9 deletion resulted in the loss of gastric acid secretion and a moderate reduction in the number of parietal cells in mutant mice at 5 weeks of age. Immunofluorescence labeling detected the H-K-ATPase exclusively on the apical pole of gastric parietal cells in Slc26a9−/−mice, in contrast to the predominant cytoplasmic localization in Slc26a9+/+mice. Light microscopy indicated that gastric glands were dilated, and electron micrographs displayed a distinct and striking absence of tubulovesicles in parietal cells and reductions in the numbers of parietal and zymogen cells in Slc26a9−/−stomach. Expression studies indicated that Slc26a9 can function as a chloride conductive pathway in oocytes as well as a Cl−/HCO3−exchanger in cultured cells, and localization studies in parietal cells detected its presence in tubulovesicles. We propose that Slc26a9 plays an essential role in gastric acid secretion via effects on the viability of tubulovesicles/secretory canaliculi and by regulating chloride secretion in parietal cells.
Highly potent, fully recombinant anti-HIV chemokines: Reengineering a low-cost microbicide
Authors: Gaertner Hubert , Cerini Fabrice , Escola Jean-Michel , Kuenzi Gabriel , Melotti Astrid , Offord Robin , Rossitto-Borlat Irène , Nedellec Rebecca , Salkowitz Janelle , Gorochov Guy , Mosier Donald , Hartley Oliver
Published: November 2008

New prevention strategies for use in developing countries are urgently needed to curb the worldwide HIV/AIDS epidemic. The N-terminally modified chemokine PSC-RANTES is a highly potent entry inhibitor against R5-tropic HIV-1 strains, with an inhibitory mechanism involving long-term intracellular sequestration of the HIV coreceptor, CCR5. PSC-RANTES is fully protective when applied topically in a macaque model of vaginal HIV transmission, but it has 2 potential disadvantages related to further development: the requirement for chemical synthesis adds to production costs, and its strong CCR5 agonist activity might induce local inflammation. It would thus be preferable to find a recombinant analogue that retained the high potency of PSC-RANTES but lacked its agonist activity. Using a strategy based on phage display, we set out to discover PSC-RANTES analogs that contain only natural amino acids. We sought molecules that retain the potency and inhibitory mechanism of PSC-RANTES, while trying to reduce CCR5 signaling to as low a level as possible. We identified 3 analogues, all of which exhibit in vitro potency against HIV-1 comparable to that of PSC-RANTES. The first, 6P4-RANTES, resembles PSC-RANTES in that it is a strong agonist that induces prolonged intracellular sequestration of CCR5. The second, 5P12-RANTES, has no detectable G protein-linked signaling activity and does not bring about receptor sequestration. The third, 5P14-RANTES, induces significant levels of CCR5 internalization without detectable G protein-linked signaling activity. These 3 molecules represent promising candidates for further development as topical HIV prevention strategies.
Ventral and dorsal pathways for language
Authors: Saur Dorothee , Kreher Björn W. , Schnell Susanne , Kümmerer Dorothee , Kellmeyer Philipp , Vry Magnus-Sebastian , Umarova Roza , Musso Mariacristina , Glauche Volkmar , Abel Stefanie , Huber Walter , Rijntjes Michel , Hennig Jürgen , Weiller Cornelius
Published: November 2008

Built on an analogy between the visual and auditory systems, the following dual stream model for language processing was suggested recently: a dorsal stream is involved in mapping sound to articulation, and a ventral stream in mapping sound to meaning. The goal of the study presented here was to test the neuroanatomical basis of this model. Combining functional magnetic resonance imaging (fMRI) with a novel diffusion tensor imaging (DTI)-based tractography method we were able to identify the most probable anatomical pathways connecting brain regions activated during two prototypical language tasks. Sublexical repetition of speech is subserved by a dorsal pathway, connecting the superior temporal lobe and premotor cortices in the frontal lobe via the arcuate and superior longitudinal fascicle. In contrast, higher-level language comprehension is mediated by a ventral pathway connecting the middle temporal lobe and the ventrolateral prefrontal cortex via the extreme capsule. Thus, according to our findings, the function of the dorsal route, traditionally considered to be the major language pathway, is mainly restricted to sensory-motor mapping of sound to articulation, whereas linguistic processing of sound to meaning requires temporofrontal interaction transmitted via the ventral route.
A role of electrical inhibition in sensorimotor integration
Authors: Weiss Shennan A. , Preuss Thomas , Faber Donald S.
Published: November 2008

Although it is accepted that extracellular fields generated by neuronal activity can influence the excitability of neighboring cells, whether this form of neurotransmission has a functional role remains open.
In vivo
field effects occur in the teleost Mauthner (M)-cell system, where a combination of structural features support the concept of inhibitory electrical synapses. A single spike in one M-cell evoked within as little as 2.2 ms of the onset of an abrupt sound, simulating a predatory strike, initiates a startle-escape behavior [Zottoli SJ (1977)
J Exp Biol
66:243–254]. We show that such sounds produce synchronized action potentials in as many as 20 or more interneurons that mediate feed-forward electrical inhibition of the M-cell. The resulting action currents produce an electrical inhibition that coincides with the electrotonic excitatory drive to the M-cell; the amplitude of the peak of the inhibition is ≈40% of that of the excitation. When electrical inhibition is neutralized with an extracellular cathodal current pulse, subthreshold auditory stimuli are converted into ones that produce an M-spike. Because the timing of electrical inhibition is often the same as the latency of M-cell firing in freely swimming fish, we conclude that electrical inhibition participates in regulating the threshold of the acoustic startle-escape behavior. Therefore, a field effect is likely to be essential to the normal functioning of the neural network.
F-pili dynamics by live-cell imaging
Authors: Clarke Margaret , Maddera Lucinda , Harris Robin L. , Silverman Philip M.
Published: November 2008

Bacteria have evolved numerous mechanisms for cell–cell communication, many of which have important consequences for human health. Among these is conjugation, the direct transfer of DNA from one cell to another. For Gram-negative bacteria, conjugation requires thin, flexible filaments (conjugative pili) that are elaborated by DNA donor cells. The structure, function, and especially the dynamics of conjugative pili are poorly understood. Here, we have applied live-cell imaging to characterize the dynamics of F-pili (conjugative pili encoded by the F plasmid of
Escherichia coli
). We establish that F-pili normally undergo cycles of extension and retraction in the absence of any obvious triggering event, such as contact with a recipient cell. When made, such contacts are able to survive the shear forces felt by bacteria in liquid media. Our data emphasize the role of F-pilus flexibility both in efficiently sampling a large volume surrounding donor cells in liquid culture and in establishing and maintaining cell–cell contact. Additionally and unexpectedly, we infer that extension and retraction are accompanied by rotation about the long axis of the filament.
Epigenetic regulation of neural cell differentiation plasticity in the adult mammalian brain
Authors: Kohyama Jun , Kojima Takuro , Takatsuka Eriko , Yamashita Toru , Namiki Jun , Hsieh Jenny , Gage Fred H. , Namihira Masakazu , Okano Hideyuki , Sawamoto Kazunobu , Nakashima Kinichi
Published: November 2008

Neural stem/progenitor cells (NSCs/NPCs) give rise to neurons, astrocytes, and oligodendrocytes. It has become apparent that intracellular epigenetic modification including DNA methylation, in concert with extracellular cues such as cytokine signaling, is deeply involved in fate specification of NSCs/NPCs by defining cell-type specific gene expression. However, it is still unclear how differentiated neural cells retain their specific attributes by repressing cellular properties characteristic of other lineages. In previous work we have shown that methyl-CpG binding protein transcriptional repressors (MBDs), which are expressed predominantly in neurons in the central nervous system, inhibit astrocyte-specific gene expression by binding to highly methylated regions of their target genes. Here we report that oligodendrocytes, which do not express MBDs, can transdifferentiate into astrocytes both
in vitro
(cytokine stimulation) and
in vivo
(ischemic injury) through the activation of the JAK/STAT signaling pathway. These findings suggest that differentiation plasticity in neural cells is regulated by cell-intrinsic epigenetic mechanisms in collaboration with ambient cell-extrinsic cues.
Gamma oscillations mediate stimulus competition and attentional selection in a cortical network model
Authors: Börgers Christoph , Epstein Steven , Kopell Nancy J.
Published: November 2008

Simultaneous presentation of multiple stimuli can reduce the firing rates of neurons in extrastriate visual cortex below the rate elicited by a single preferred stimulus. We describe computational results suggesting how this remarkable effect may arise from strong excitatory drive to a substantial local population of fast-spiking inhibitory interneurons, which can lead to a loss of coherence in that population and thereby raise the effectiveness of inhibition. We propose that in attentional states fast-spiking interneurons may be subject to a bath of inhibition resulting from cholinergic activation of a second class of inhibitory interneurons, restoring conditions needed for gamma rhythmicity. Oscillations and coherence are emergent features, not assumptions, in our model. The gamma oscillations in turn support stimulus competition. The mechanism is a form of “oscillatory selection,” in which neural interactions change phase relationships that regulate firing rates, and attention shapes those neural interactions.
Katanin Knockdown Supports a Role for Microtubule Severing in Release of Basal Bodies before Mitosis inChlamydomonas
Authors: Rasi M. Qasim , Parker Jeremy D.K. , Feldman Jessica L. , Marshall Wallace F. , Quarmby Lynne M.
Published: November 2008

Katanin is a microtubule-severing protein that participates in the regulation of cell cycle progression and in ciliary disassembly, but its precise role is not known for either activity. Our data suggest that in Chlamydomonas, katanin severs doublet microtubules at the proximal end of the flagellar transition zone, allowing disengagement of the basal body from the flagellum before mitosis. Using an RNA interference approach we have discovered that severe knockdown of the p60 subunit of katanin, KAT1, is achieved only in cells that also carry secondary mutations that disrupt ciliogenesis. Importantly, we observed that cells in the process of cell cycle-induced flagellar resorption sever the flagella from the basal bodies before resorption is complete, and we find that this process is defective in KAT1 knockdown cells.
Antioxidant Levels Represent a Major Determinant in the Regenerative Capacity of Muscle Stem Cells
Authors: Urish Kenneth L. , Vella Joseph B. , Okada Masaho , Deasy Bridget M. , Tobita Kimimasa , Keller Bradley B. , Cao Baohong , Piganelli Jon D. , Huard Johnny
Published: November 2008

Stem cells are classically defined by their multipotent, long-term proliferation, and self-renewal capabilities. Here, we show that increased antioxidant capacity represents an additional functional characteristic of muscle-derived stem cells (MDSCs). Seeking to understand the superior regenerative capacity of MDSCs compared with myoblasts in cardiac and skeletal muscle transplantation, our group hypothesized that survival of the oxidative and inflammatory stress inherent to transplantation may play an important role. Evidence of increased enzymatic and nonenzymatic antioxidant capacity of MDSCs were observed in terms of higher levels of superoxide dismutase and glutathione, which appears to confer a differentiation and survival advantage. Further when glutathione levels of the MDSCs are lowered to that of myoblasts, the transplantation advantage of MDSCs over myoblasts is lost when transplanted into both skeletal and cardiac muscles. These findings elucidate an important cause for the superior regenerative capacity of MDSCs, and provide functional evidence for the emerging role of antioxidant capacity as a critical property for MDSC survival post-transplantation.
TheUNI1andUNI2Genes Function in the Transition of Triplet to Doublet Microtubules between the Centriole and Cilium inChlamydomonas
Authors: Piasecki Brian P. , Silflow Carolyn D.
Published: November 2008

One fundamental role of the centriole in eukaryotic cells is to nucleate the growth of cilia. The unicellular alga Chlamydomonas reinhardtii provides a simple genetic system to study the role of the centriole in ciliogenesis. Wild-type cells are biflagellate, but “uni” mutations result in failure of some centrioles (basal bodies) to assemble cilia (flagella). Serial transverse sections through basal bodies in uni1 and uni2 single and double mutant cells revealed a previously undescribed defect in the transition of triplet microtubules to doublet microtubules, a defect correlated with failure to assemble flagella. Phosphorylation of the Uni2 protein is reduced in uni1 mutant cells. Immunogold electron microscopy showed that the Uni2 protein localizes at the distal end of the basal body where microtubule transition occurs. These results provide the first mechanistic insights into the function of UNI1 and UNI2 genes in the pathway mediating assembly of doublet microtubules in the axoneme from triplet microtubules in the basal body template.