cssi/SciSciGPT-SciSciNet huggingface dataset:
Cerebral fat embolism syndrome in sickle cell anaemia/β-thalassemia: Importance of susceptibility-weighted MRI

Fat embolism syndrome is a rare, but potentially lethal complication of sickle cell disease, with mortality ranging from 5e15%.1e6 Most commonly, fat embolism syndrome presents after trauma, typically after long bone fractures, but it can also occur in non-traumatic disorders including the postoperative setting, diabetes, neoplea, blood transfusions, or cardiopulmonary bypass.3,7,8 Fat embolism syndrome has been recognized as a complication of acute chest syndrome in sickle cell disease.9 After a 12e48 h symptom-free period, patients usually present with progressive respiratory distress, cerebral involvement (seizures, decreased level of consciousness, and focal neurological deficits), and skin and mucosal petechiae. Secondary diagnostic signs include fever, tachycardia, retinal changes, jaundice, and renal disease.10 Cerebral fat embolism syndrome can be seen in up to 86% of cases of fat embolism, resulting in embolic brain micro-infarcts, vasogenic oedema, and petechial haemorrhages.2 Many cases of cerebral fat embolism syndrome in sickle cell patients are not diagnosed until autopsy, highlighting the importance of recognizing this clinical entity on imaging studies.4,11e13 When recognized and treated appropriately, fat embolism syndrome in sickle cell disease is curable.9 Only a few case reports of fat embolism syndrome in sickle cell/b-thalassemia patients are in the literature,1,2,4,6,14 and there are even fewer case reports that included haem-sensitive sequences [T2 gradient echo and susceptibility weighted imaging (SWI)], but to the authors’ knowledge none of these reports included SWI.15,16
Path integral Monte Carlo simulations of nanowires and quantum point contacts

We study quantum wires and point contacts with a fixed-node path integral Monte Carlo technique. The fixed-node technique uses a variational principle to map fermionic problems into effective bosonic problems, which are then evaluated with standard quantum Monte Carlo techniques. While fixed-node is an approximation, it has the useful properties of being variational and being able to recover the exact answer when the exact nodes or phases of the density matrix are known. In these finite-temperature simulations we use the free particle density matrix as a fixed-node constraint to efficiently simulate hundreds of interacting electrons. We have calculated charge densities, pair correlation functions, and the currentcurrent Matsubura Green's functions for quantum wires and quantum point contacts.
The role of contraceptive attributes in women’s contraceptive decision making

Objective Contraceptive methods have differing attributes. Women's preferences for these attributes may influence contraceptive decision making. Our objective was to identify women's contraceptive preferences among women initiating a new contraceptive method. Study Design We conducted a cross-sectional, self-administered survey of women's contraceptive preferences at the time of enrollment into the Contraceptive CHOICE Project. Participants were asked to rank the importance of 15 contraceptive attributes on a 3-point scale (1 = not at all important, 2 = somewhat important, and 3 = very important) and then to rank the 3 attributes that were the most important when choosing a contraceptive method. The survey also contained questions about prior contraceptive experience and barriers to contraceptive use. Information about demographic and reproductive characteristics was collected through the CHOICE Project baseline survey. Results There were 2590 women who completed the survey. Our sample was racially and socioeconomically diverse. Method attributes with the highest importance score (mean score [SD]) were effectiveness (2.97 [0.18]), safety (2.96 [0.22]), affordability (2.61 [0.61]), whether the method is long lasting (2.58 [0.61]), and whether the method is "forgettable" (2.54 [0.66]). The attributes most likely to be ranked by respondents among the top 3 attributes included effectiveness (84.2%), safety (67.8%), and side effects of the method (44.6%). Conclusion Multiple contraceptive attributes influence decision making and no single attribute drives most women's decisions. Tailoring communication and helping women make complex tradeoffs between attributes can better support their contraceptive decisions and may assist them in making value-consistent choices. This process could improve continuation and satisfaction.
Expanding the benefits of computational thinking to diverse populations: Graduate student consortium

The sixth annual graduate consortium at VL/HCC addresses the question: How can researchers and designers of end-user development environments support computational problem-solving and information manipulation by diverse user populations?
Sensor-Based Collision Avoidance: Theory and Experiments

A new on-line control strategy for sensor-based collision avoidance of manipulators and supporting experimental results are presented in this article. This control strategy is based on nullification of virtual forces applied to the end-effector by a hypothetical spring-plus-damper attached to the object's surface. In the proposed approach, the real-time arm control software continuously monitors the object distance measured by the arm-mounted proximity sensors. When this distance is less than a preset threshold, the collision avoidance control action is initiated to inhibit motion toward the object and thus prevent collision. This is accomplished by employing an outer feedback loop to perturb the end-effector nominal motion trajectory in real-time based on the sensory data. The perturbation is generated by a proportional-plus-integral (PI) collision avoidance controller acting on the difference between the sensed distance and the preset threshold. This approach is computationally very fast, requires minimal modification to the existing manipulator positioning system, and provides the manipulator with an on-line collision avoidance capability to react autonomously and intelligently. A dexterous RRC robotic arm is instrumented with infrared proximity sensors and is operated under the proposed collision avoidance strategy. Experimental results are presented to demonstrate end-effector collision avoidance both with an approaching object and while reaching inside a constricted opening.
The Kinetics of Rectal Absorption II. : The Absorption of Anions

The rectal absorption rates of sodium iodide and the sodium salt of 2,4,6-triiodophenol in suppository bases at various pH values and in the presence of surface-active agents and polyethylene glycol additives were determined by continuous external detection at the site of insertion. The rate of sodium iodide absorption is accelerated in the presence of surfactants and appears to be proportional to the surface tension lowering and the peptizing action of their surface active components. The rate of absorption of the phenolate is retarded by the presence of surfactants. Hydrolysis and subsequent solubilization of the free phenol is postulated to explain this effect.
Variational theory of valence fluctuations: Ground states and quasiparticle excitations of the Anderson lattice model.

A variational study of ground states of the orbitally nondegenerate Anderson lattice model, using a wave function with one variational parameter per Bloch state k, has been extended to deal with essentially metallic systems having a nonintegral number of electrons per site. Quasiparticle excitations are obtained by direct appeal to Landau's original definition for interacting Fermi liquids, ${\mathrm{scrE}}_{\mathrm{q}\mathrm{p}(k}$,${\mathit{\ensuremath{\sigma}})=\mathit{\ensuremath{\delta}}\mathit{E}}_{\mathrm{total}}$/\ensuremath{\delta}n qp(k,\ensuremath{\sigma}).
Photochemistry of alkyl halides, 5. 2,4-dehydroadamantane and protoadamantene from 2,-bromo- and 2-iodoadamantane

Bei der Photolyse der 2-Halogen-adamantane (I) erhalt man je nach den angewandten Bedingungen in Diethylether oder Methanol Mischungen aus Adamantan (II), den durch innermolekulare Einschiebung gebildeten Dehydroverbindungen (III) und (IV) sowie den AdamantanylQ-ethern (V).
Longitudinal Outcomes for Youth Receiving Runaway/Homeless Shelter Services

This research examined outcomes and use of specific types of services 6 weeks, 3 and 6 months post-discharge for a large sample of runaway/homeless youth using crisis shelter services. Data were collected for 371 runaway/homeless youth using emergency shelter and crisis services at eleven agencies across a four-state midwestern region. Outcomes were assessed for runaway behavior, family relationships, substance use, school behavior, employment, sexual behavior, and self-esteem. Additionally, the impact of services on outcomes was assessed. Findings indicated that although youth achieved a wide variety of positive outcomes 6 weeks post-discharge, there were signs of attenuation of certain outcomes by the 6 month follow-up. Service use after discharge did not demonstrate a strong impact on maintaining outcomes. The substantive findings reported here present encouraging evidence for providers of services for runaway/homeless youth. Crisis shelter services appear to facilitate broad-based short-term gains, but do not appear sufficient to maintain these gains over an extended period.
A method for ensemble expansion and improved definition of forecast distributions from climate simulations

Because of the inherently chaotic nature of the atmosphere, ensemble simulations are required to characterize a model's response to the prescribed boundary forcing in probabilistic terms, particularly if the focus is on the probabilities of extreme events. At the same time, substantial computer resources are needed to produce routinely ensemble seasonal climate forecasts of sufficient size to make suitably reproducible estimates of such probabilities. We describe a method for artificially expanding the effective number of members in ensemble climate simulations on a seasonal basis, thereby reducing uncertainty in estimated probability distributions. As described here, the method involves calculating seasonal statistics using monthly values from all possible combinations of ensemble members. Under certain assumptions, this method is able to increase the effective ensemble size of an N-member M-month seasonal forecast by a factor of (asymptotically) M. One key assumption in this regard is that, aside from the effects of prescribed boundary conditions, the month-to-month values from a particular ensemble member are linear independent. This paper describes the behaviour of the ensemble expansion technique using both idealized and actual ensemble forecast data under a variety of conditions, drawing comparisons with an alternative parametric approach for ensemble expansion. A method for testing the assumption of linear independence in model simulations is also presented. Copyright © 2005 Royal Meteorological Society
Selective Dehydrogenation of 1,3-Cyclohexadiene on Ordered Sn/Pt(111) Surface Alloys

The adsorption and dehydrogenation of 1,3-cyclohexadiene on Pt(111) and two Sn/Pt(111) surface alloys has been studied using TPD, AES, and LEED. The two Pt−Sn surfaces investigated are well-defined, monolayer-thick surface alloys with either a p(2×2) or (√3×√3)R30° LEED pattern and ϑsn = 0.25 or 0.33, respectively. Cyclohexadiene chemisorption on Pt(111) is irreversible and all the chemisorbed monolayer dehydrogenates to form benzene upon heating. Further heating causes most of this benzene product to dehydrogenate completely to form a carbonaceous residue. Some benzene desorbs from the surface at higher coverages. Alloying the Pt surface with Sn completely eliminates the decomposition of benzene without inhibiting the reactivity of cyclohexadiene, dramatically increasing (to 100%) the selectivity of the Pt−Sn surface alloys for gas-phase benzene production. Finally, we observe that the benzene evolution undergoes a stepwise decrease in temperature with increasing Sn concentration and we attribute this to...
Recent advances in biocatalyst discovery, development and applications.

Abstract Enzymes catalyze a wide range of biotransformations and have a great potential as environmentally friendly alternatives to classical chemical catalysts in various industrial applications. Recently, advanced techniques and strategies in enzyme discovery and engineering have led to the significant expansion of the quantity and functional diversity of biocatalysts, which has further allowed broader uses of biocatalysts in new processes, especially those traditionally enabled only by chemical catalysts. Here we highlight some of these recent advances with the focus on new approaches in biocatalyst discovery and development, and discuss new applications of selected biocatalysts including transaminases, cytochrome P450s, and Baeyer–Villiger monooxygenases.
“We need progress, progress has to be made:” Road projects, subaltern politics, and uneven development in Nicaragua

The focus of this article is a rural road building project that was celebrated by its promoters as a dream of historic proportions comes true. The significance of this road project rests not in its length or quality, but in its trajectory or the way it encapsulates processes of neoliberal restructuring that link the rescaling of state, processes of transnational territorial integration, and new spaces and subjects of governance. The road project, its participants and promoters, and the meanings they attributed to it, were informed by a much longer, if already translocal “local” history. But forms of neoliberal transnational governmentality provided a framework that allowed some subaltern actors to at once press for the road and articulate a new politics of place, a larger project that they called “progress.” Yet, the very conditions that made the pursuit of progress possible, threatened at every moment to undermine its promise. Thus, this road project provides a unique vantage point for exploring the para...
Production of public safety: Are socioeconomic characteristics of local communities important factors?

This paper uses the translog cost function and cross section data from Florida to investigate the importance of socioeconomic characteristics (SEC) of local communities in the production of public safety. The approach used is noteworthy in four respects: (1) the underlying production function is specified as an AGEM production function; (2) SEC are treated as non-purchased fixed inputs; (3) two variables are used to proxy SEC in estimation; and (4) the paper test for the existence of endogenous quality differences in safety. It is shown that exclusion of SEC from the production (cost) function of safety leads to misspecification; and hence they provide a misleading guide to policy.
A Modification of the Vasodilatation Test

Abstract The vasodilatation test, the measurement of blood flow when vasomotor tone is abolished, can be a determining factor in deciding whether or not arterial surgery should be attempted. The purpose of this work is to show the advantages in time, and usually in accuracy, of placing patients in a state of vasodilatation when performing the test. An advantage gained by allowing the feet to be in a slightly dependent position is also demonstrated.
Identifying risk for recurrent hepatocellular carcinoma after liver transplantation: Implications for surveillance studies and new adjuvant therapies

The recurrence of hepatocellular carcinoma (HCC) is a major cause of mortality for patients transplanted with HCC. There currently exists no standard method for identifying those patients with a high risk for recurrence. Identification of factors leading to recurrence is necessary to develop an efficient surveillance protocol and address new potential adjuvant therapies. We conducted a retrospective review of 834 consecutive liver transplants from 1/1/1996 to 12/31/2005 (mean follow-up 1303 ± 1069 days) at one institution and 352 consecutive transplants from 1/2/2002 to 12/31/2005 (mean follow-up 836 ± 402 days) at a second institution. The test cohort comprised patients identified with HCC in their explanted livers from 1/1/2001 to 12/31/2005 at the first institution. Explant pathology and donor and recipient characteristics were reviewed to determine factors associated with HCC recurrence. These predictors were validated in the remaining liver transplant recipients. The test cohort had 116 patients with findings of HCC in their explanted livers. Twelve patients developed recurrent HCC. Stepwise logistic regression identified 4 independent significant explant factors predictive of recurrence. Size of one tumor (>4.5 cm), macroinvasion, and bilobar tumor were positive predictors of recurrence, whereas the presence of only well-differentiated HCC was a negative predictor. Designating each significant factor with points in relation to its odds ratio, a Predicting Cancer Recurrence Score (PCRS) with results ranging from −3 to 6 was developed that accurately determined risk of recurrence. These findings were then applied to the two validation cohorts, which confirmed the high predictive value of this model. In conclusion, patients transplanted for HCC with a PCRS of ≤0 have a low risk of recurrence. Patients with a PCRS of 1 or 2 have a moderate risk of recurrence, and those with a PCRS of ≥3 have a high risk for recurrence. Liver Transpl 14:956–965, 2008. © 2008 AASLD.
An Assessment of Computational Fluid Dynamic Techniques in the Analysis and Design of Turbomachinery—The 1990 Freeman Scholar Lecture

Various computational fluid dynamic techniques are reviewed focusing on the Euler and Navier-Stokes solvers with a brief assessment of boundary layer solutions, and quasi-3D and quasi-viscous techniques. Particular attention is given to a pressure-based method, explicit and implicit time marching techniques, a pseudocompressibility technique for incompressible flow, and zonal techniques. Recommendations are presented with regard to the most appropriate technique for various flow regimes and types of turbomachinery, incompressible and compressible flows, cascades, rotors, stators, liquid-handling, and gas-handling turbomachinery.
SU‐D‐WAB‐05: Image‐Based Proton Range Verification Using Intensity‐Corrected CBCT

Purpose: Using CBCT to detect variations in proton beam path prior to treatment is an important step in the quality assurance of proton therapy. However, the Hounsfield Units (HUs) from a CBCT differs slightly from a simulation CT, thereby introducing additional uncertainties in the conversion from HUs to proton stopping power. The aim of this work is to demonstrate the feasibility of using deformable image registration to map simulation CT HUs onto a treatment CBCT for range verification during proton therapy. Methods: A simulation CT and two simulated proton CBCT of a head and neck patient were used in this study. We used a diffeomorphic deformable image registration algorithm with symmetric normalization in conjunction with cross correlation similarity metrics (ANTs: Advanced Normalization Tools) to deform the simulation CT onto the CBCTs. Polar plots of proton beam water equivalent thickness (WET) were generated using a ray tracing algorithm at different gantry angles in the unmodified CBCT, corrected CBCT and simulation CT for analysis. Results: With no anatomical variation, corrected CBCT and simulation CT image exhibited excellent agreement in WETs (mean difference of 1.26 mm, interquartile range 0.42∼1.79mm). In the unmodified CBCT image, larger difference in WETs (mean value 3.38 mm, interquartile range 1.90∼5.03mm) attributed to errors in HU to stopping power conversion were observed. With tumor shrinkage the differences in the WET polar plots between planning CT and corrected CBCT correlated with the location of anatomical change in the nasal/oral cavity, indicating potential deviations in proton dose deposition. Conclusion: It is feasible to use deformable image registration to correct CBCT HUs for image based proton range verification. Polar plots of deviations in WET between CBCT and simulation CT is potentially an efficient and practical quality assurance tool in the use of CBCT for proton therapy applications.
Interaction of Carotenoids and Cu2+ in Cu-MCM-41: Distance-Dependent Reversible Electron Transfer

Carotenoids (Car), β-Carotene (I), 8‘-apo-β-caroten-8‘-al (II), and canthaxanthin (III), incorporated into activated Cu−MCM-41 were examined by UV/vis and EPR spectroscopies. A Cu2+−Car complex was formed for I and III but not for II. Formation of a complex results in distortion of the all-trans carotenoid geometry and a tetragonal geometry for Cu2+. The binding energies of Car and Cu2+, the changes in the maximum absorption, and the bond lengths of Car after the formation of the Cu2+−Car complex were examined by semiempirical ZINDO/1 and ZINDO/S calculations. Formation of a complex between Car and Cu2+ favors both forward and back electron transfer (ET) reactions due to the short distance (∼2 A) between Car and Cu2+, and reversible ET appears upon temperature cycling.
Talc under tension and compression: Spinodal instability, elasticity, and structure

[1] Talc occurs as a product of alteration of ultramafic rocks and may be a significant constituent of oceanic lithosphere and the arc mantle wedge. We explore the physical properties and structure of talc over a wide pressure range with density functional theory using the variable cell shape plane wave pseudopotential method in the local density (LDA) and generalized gradient (GGA) approximations. For LDA, the theoretical equation of state agrees with room temperature experimental measurements of the volume to within 2% when estimated effects of lattice vibrations are accounted for. We predict a spinodal mechanical instability (vanishing bulk modulus) at a volume 4% larger than the experimental volume at ambient conditions. Results for compression and tension are well 2represented by a fourth-order Birch-Murnaghan finite strain expansion with K-0 = 37.8, K-0' = 13.6, K0K0" = 153, where K is the bulk modulus, primes indicate pressure derivatives and subscript 0 refers to zero pressure. The estimated theoretical value of K-0 at 300 K (29 GPa) is considerably less than that determined from the experimental equation of state, a difference we attribute to the constraints of strain compatibility in the polycrystalline laboratory sample. The c* = c sin beta axis is found to be a factor of 7 more compressible than the b axis, consistent with experimental data. Compression in the a-b plane is accommodated primarily by the Mg-octahedra. The polyhedral bulk modulus of the Mg-octahedra is considerably greater than one-third the linear modulus of the a axis. The difference is attributed to the increasing regularity of the Mg-octahedra on compression as measured by the octahedral tilt angle. The t sheet maintains registry with the o sheet by rotation of the Si-tetrahedra; the tetrahedral rotation angle rises from a value of 3degrees at the experimental volume to a theoretically predicted value of 22degrees at a volume of 170 Angstrom(3) where the pressure is 26 GPa. Tetrahedral rotation leads to small Si-O-Si angles at the highest pressures investigated (<122degrees at 26 GPa), which leads us to speculate that talc may undergo pressure-induced amorphization under low-temperature compression.
Group binary decision making with multiple agents

Decision making and analysis are frequently considered from the perspective of a sole Decision Maker (DM). In practice, however, decision making is often conducted by a group of DMs. This paper presents a decision analysis problem involving multiple DMs or agents. A simple two-state two-action decision problem where N DMs receive individual information about the occurrence of the two states is considered. After reviewing their information, each DM recommends an action to adopt. The individual actions are then combined into a single final group action. Optimal decisions that maximise an expected payoff are sought. An analysis approach, alike statistical hypothesis testing and involving Receiver Operating Characteristic (ROC) curves is used to investigate the problem.
Rapid beam scanning using a mode-locked laser-driven laser array

A scheme for driving a laser-array with the spatially dispersed spectral components of a mode-locked laser to achieve very rapid ( >
Crystal structures of CaSiO3 polymorphs control growth and osteogenic differentiation of human mesenchymal stem cells on bioceramic surfaces

The repair and replacement of damaged or diseased human bone tissue requires a stable interface between the orthopedic implant and living tissue. The ideal material should be both osteoconductive (promote bonding to bone) and osteoinductive (induce osteogenic differentiation of cells and generate new bone). Partially resorbable bioceramic materials with both properties are developed by expensive trial-and-error methods. Structure-reactivity relationships for predicting the osteoinductive properties of ceramics would significantly increase the efficiency of developing materials for bone tissue engineering. Here we propose the novel hypothesis that the crystal structure of a bioceramic controls the release rates, subsequent surface modifications due to precipitation of new phases, and thus, the concentrations of soluble factors, and ultimately, the attachment, viability and osteogenic differentiation of human Mesenchymal Stem Cells (hMSCs). To illustrate our hypothesis, we used two CaSiO3 polymorphs, pseudo-wollastonite (psw, β-CaSiO3) and wollastonite (wol, α-CaSiO3) as scaffolds for hMSC culture. Polymorphs are materials which have identical chemical composition and stoichiometry, but different crystal structures. We combined the results of detailed surface characterizations, including environmental Scanning Electron Microscopy (SEM) back-scattered imaging, and spot-analysis and 2D elemental mapping by SEM-Energy Dispersive X-ray (SEM-EDX), High Resolution Transmission Electron Microscopy (HRTEM) and surface roughness analysis; culture medium solution analyses; and molecular/genetic assays from cell culture. Our results confirmed the hypothesis that the psw polymorph, which has a strained silicate ring structure, is more osteoinductive than the wol polymorph, which has a more stable, open silicate chain structure. The observations could be attributed to easier dissolution (resorption) of psw compared to wol, which resulted in concentration profiles that were more osteoinductive for the former. Thus, we showed that crystal structure is a fundamental parameter to be considered in the intelligent design of pro-osteogenic, partially resorbable bioceramics.
High-displacement piezoelectric actuator utilizing a meander-line geometry I. Experimental characterization

The compact linear-motion piezoelectric actuator developed has relatively large displacement capabilities. It is composed of a number of parallel bars of lead zirconium titanate (PZT) connected together in a meander-line configuration so that they are mechanically in series and electrically in parallel. The polarity of the adjacent bars is arranged so that if a given bar expands under the applied voltage, the adjacent bars contract. An electromechanical model of the actuator predicted and measurements verified that stiffeners added to the basic meander line geometry significantly increased the force output without affecting the displacement versus applied voltage relationship. >
Cross-saturation effects on position estimation using BEMF methods in PMAC machines

Under load and in the presence of saturation in particular, PMAC machines exhibit the magnetic axis shift from the rotor position, which in turn causes an error in a control algorithm that uses conventional rotor position estimation. This error is particularly pronounced in the shaft-sensorless position estimation based on the back EMF measurements since most conventional algorithms completely ignore the existence of the cross-saturation i.e. cross-coupling inductance L qd is assumed to be zero. The described error is a function of operating point and local saturation levels so it is intuative to conclude that it will also be impacted by various machine parameters such as; rotor geometry, winding configuration and so on. In this paper we conduct a comparative study to show the influence of the various PMAC machine topologies on the magnitude of the described error, while utilizing an existing back EMF based position sensorless controller. The impact of the error on the machine performance is also examined. Four major types of PMAC machines are considered; surface and interior permanent magnet machines with concentrated and distributed winding configurations. First, we will use a non-linear mode to analytically characterize this error for an arbitrary PMAC machine and use the FEA to characterize the error for the specific IPM and SPM machines with distributed and concentrated winding topologies. Finally, degradation in the torque-speed capability and efficiency over the entire operating range of the machines due to the error will be also presented.
Conjugating the “Tenses” of Function: Discordance Among Hypothetical, Experimental, and Enacted Function in Older Adults

Within the field of aging, the conceptualization and measurement of functioning has been dominated by the disability model. In this paper, one limitation of that model is described by calling attention to a distinction between three "tenses" of functioning. Inadequate attention has been paid to the distinction between the capacity to function in the abstract (hypothetical tense) and actual performance in daily life (enacted tense). Failure to attend to this distinction has obscured considerable discordance between what people say they are able to do in standard functional disability assessments, and what they actually do at home. To illustrate this point, data from the MacArthur Studies of Successful Aging comparing the hypothetical to the enacted tenses are presented. These data show a consistent pattern of discordance between these two tenses.
Livestock development programmes for communities in low- and middle-income countries

Reason for withdrawal from publication Protocol withdrawn 28/6/18 - Authors have made no progress with this protocol since publication in 2013. Lead author has confirmed the authorship team are unable to complete the review.
Brain-control interfaces for sensory and motor prosthetic devices

Injury and disease to the central nervous system often leaves patients with full cognitive ability but a loss of communication between the brain and sensorimotor systems of the rest Of the body. During the past 30 years there has been tremendous progress in the development of prosthetic devices that stimulate peripheral nerves and muscles to restore movement of paralyzed limbs in these patients. However, control systems for these prosthetic devices that interface directly with brain signals carrying information about the intent to move and methods for returning sensory feedback to the brain are just beginning to be developed. We present a ceramic-based, multi-site electrode system capable of: (1) recording from large numbers of neurons across several brain regions; (2) stimulating neural tissue to restore sensory feedback; and (3) measuring local concentrations of neuromodulators. Preliminary data from the rat suggest that this system can be used to record neural signals carrying information about the intent to move and restore sensory perception. Issues relating to interfacing with the brain's hierarchical and distributed information processing systems are discussed.
α-Endosulfine is a conserved protein required for oocyte meiotic maturation in Drosophila

Meiosis is coupled to gamete development and must be well regulated to prevent aneuploidy. During meiotic maturation, Drosophila oocytes progress from prophase I to metaphase I. The molecular factors controlling meiotic maturation timing, however, are poorly understood. We show that Drosophila α -endosulfine ( endos ) plays a key role in this process. endos mutant oocytes have a prolonged prophase I and fail to progress to metaphase I. This phenotype is similar to that of mutants of cdc2 (synonymous with cdk1 ) and of twine , the meiotic homolog of cdc25, which is required for Cdk1 activation. We found that Twine and Polo kinase levels are reduced in endos mutants, and identified Early girl (Elgi), a predicted E3 ubiquitin ligase, as a strong Endos-binding protein. In elgi mutant oocytes, the transition into metaphase I occurs prematurely, but Polo and Twine levels are unaffected. These results suggest that Endos controls meiotic maturation by regulating Twine and Polo levels, and, independently, by antagonizing Elgi. Finally, germline-specific expression of the humanα -endosulfine ENSA rescues the endos mutant meiotic defects and infertility, and α-endosulfine is expressed in mouse oocytes, suggesting potential conservation of its meiotic function.
The physics of laser acceleration of particles

In our quest to build higher energy accelerators that are both cheaper and smaller, we search for new paradigms that offer potentially high accelerating gradients. The laser features very prominently in many of these schemes. The proposed use of lasers to accelerate particles to ultra-high energies has been motivated by the very high electric fields associated with focused laser beams. A number of conceptually different schemes have been proposed for this purpose and are under very active investigation. In the last couple of years significant results have been obtained on four of these schemes: the inverse-Cherenkov accelerator, the inverse-free-electron laser accelerator, the laser-plasma beat-wave accelerator, and the self-modulated laser wake-field accelerator. Of these, the first two are an example of what is known as far-field accelerators, that is, the acceleration of charges takes place far away from any solid surfaces. On the other hand, the latter two are an example of acceleration by a space charge wave that is induced by a laser beam in an ionized medium: a plasma.
Flow cytometric analysis of bromodeoxyuridine-substituted cells stained with 33258 Hoechst.

This paper describes a flow-cytometnic application of the quenching of fluorescence from 33258 Hoechst stained Chinese hamster ovary-line cells due to the incorporation of 5-bromodeoxyuridine (BrdU) into the cellular deoxyribonucleic acid. Cells were grown for 24 hr in medium containing BrdU in concentrations ranging from 1 x 108 to 1 x 10� M. For each concentration we measured the average fluorescence as determined by flow cytometry, the extent of BrdU substitution and the effect of the BrdU on cell growth. We determined that a BrdU concentration of 1 x 10� M resulted in sufficient substitution to quench the fluorescence from 33258 Hoechst by a factor of 4, allowing discrimination between cycling and noncycling cells. The extent of BrdU substitution after growth for 24 hr in this concentration of BrdU was 64%. These data indicate the feasibility of detecting deoxyribonucleic acid synthesis in whole cells using the 33258 Hoechst-BrdU methodology.
Sex differences in preadolescent self-esteem

It was predicted from the theories of Bardwick that 1) made self-esteem would be greater than female self-esteem only among the older children of the preadolescent sample, 2) reading achievement would correlate with self-esteem for boys in all age groups but only for the younger girls, and 3) individual self-esteem items that showed sex differences would be sex-role related. Data on self-esteem and reading score were collected on 307 urban children in second through sixth grades. Analysis of results confirmed predictions 1 and 3, but not prediction 2. Reading score did not show a significant correlation with self-esteem for girls at any age level tested. Results were discussed in terms of differing sources of male and female self-esteem.
Admission control schemes for wireless communication networks with adjustable transmitter powers

When new mobiles are admitted in some channel of a wireless communication network traditional power control algorithms cannot foresee the effect that new admissions have on the signal-to-interference ratios (SIR) of active mobiles already using the channel, and may cause fluctuations of their SIR below acceptable levels during the process. The authors present two algorithms that manage transmission power and channel admissions jointly to maintain the SIR of all links above some quality factor /spl gamma/ at all times. This joint control of power and channels results in high channel reuse. >
Fracture Behavior of Epoxy-Based, Hybrid Particulate Composites

Epoxy-based, particulate composites are commonly used in packaging applications for the microelectronics industry. For example molding compounds, die attach adhesives, and encapsulant resins are all polymer matrix, particulate-reinforced composites. The mechanical behavior of these materials is a function of the type of resin, the shape and size of the reinforcing particles, the filler content, etc. In this paper, we will examine the interactions of the toughening mechanisms between rubber particles and the reinforcing particles. Hybrid-particulate composites are prepared by compounding both rubber particles and disc-shaped boron nitride particles in a bisphenol A-based epoxy cured with piperidine. Interestingly, there are combinations of rubber and reinforcing particles that lead to synergistic toughening. The underlying causes for synergistic toughening will be discussed.
Increased Cerebrospinal Fluid Norepinephrine in Essential Hypertension

Studies in man and animals suggest increased central noradrenergic activity in hypertension. We can now measure norepinephrine (NE) in cerebrospinal fluid (CSF) accurately and this should provide an index of central noradrenergic activity. NE in CSF is very labile and altered by anxiety, stress, drugs, sodium balance and other factors. When these factors are controlled, NE in CSF appears elevated in essential hypertensives, particularly among young patients. Neurologic diseases that alter NE in CSF cause parallel alterations in blood pressure. Increased central noradrenergic activity is reflected in CSF NE levels and may cause some forms of hypertension.
TRAIL Inactivates the Mitotic Checkpoint and Potentiates Death Induced by Microtubule-Targeting Agents in Human Cancer Cells

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has attracted interest as an anticancer treatment, when used in conjunction with standard chemotherapy. We investigated the mechanistic basis for combining low-dose TRAIL with microtubule-targeting agents that invoke the mitotic checkpoint. Treatment of T98G and HCT116 cells with nocodazole alone resulted in a robust mitotic block with initially little cell death; low levels of cell death were also seen with TRAIL alone at 10 ng/mL final concentration. In contrast, the addition of low-dose TRAIL to nocodazole was associated with maximally increased caspase-3, caspase-8, and caspase-9 activation, which efficiently abrogated the mitotic delay and markedly increased cell death. In contrast, the abrogation of mitotic checkpoint and increased cell death were blocked by inhibitors of caspase-8 and caspase-9 or pan-caspase inhibitor. The addition of TRAIL to either nocodazole or paclitaxel (Taxol) reduced levels of the mitotic checkpoint proteins BubR1 and Bub1. BubR1 mutated for the caspase cleavage sites, but not wild-type BubR1, was resistant to cleavage induced by TRAIL added to nocodazole, and partially blocked the checkpoint abrogation. These results suggest that adding a relatively low concentration of TRAIL to antimicrotubule agents markedly increases complete caspase activation. This in turn accentuates degradation of spindle checkpoint proteins such as BubR1 and Bub1, contributes to abrogation of the mitotic checkpoint, and induces cancer cell death. These results suggest that TRAIL may increase the anticancer efficacy of microtubule-targeting drugs.
Designer, Analyst, Tinker: How Game Analytics Will Contribute to Science

If you were watching the world of science in 1835, you would be fairly certain of one thing: we would never know what stars are made of. By that time scientists had discovered that the stars were quite far away and they could not imagine any technology that would take humans from this planet to those places and back again. Then one day, Robert Bunsen (of the burner) and his colleague Gustav Kirchhoff noticed that when elements were placed in a hot fire, the light they emitted proved to have a signature distribution of color on the spectrum. A spectrograph observation of burning helium looks different, uniquely and reliably, than one of burning nitrogen. In the instant of discovery, the two scientists had learned how to sample the stars.
Neurologic Outcome in Neonatal Temporal Lobe Hemorrhagic Venous Infarcts

Consequences of neonatal cerebral venous infarct can be severe. However, we have identified a series of neonates with unilateral temporal lobe infarcts, suspected to be secondary to superficial cortical venous thrombosis, who have had relatively normal outcomes. Medical records were reviewed retrospectively. History, relevant studies, and outcomes for 7 patients are described. Most patients presented with neonatal seizures. Neuroimaging showed unilateral temporal lobe hemorrhage and surrounding ischemic change, which was initially attributed to thrombosis of the vein of Labbe; however, magnetic resonance venogram findings suggest that thrombosis of other superficial temporal lobe veins may also be involved. Seizure control was achieved in all cases. Development and neurologic examination at follow-up were usually normal. We conclude that neonatal temporal lobe hemorrhagic infarct secondary to suspected superficial temporal venous thrombosis appears to have a good clinical outcome. This is surprising, given the dramatic imaging and clinical presentations.
A Composite Element that Binds Basic Helix Loop Helix and Basic Leucine Zipper Transcription Factors Is Important for Gonadotropin-Releasing Hormone Regulation of the Follicle-Stimulating Hormone β Gene

Although FSH plays an essential role in controlling gametogenesis, the biology of FSHβ transcription remains poorly understood, but is known to involve the complex interplay of multiple endocrine factors including GnRH. We have identified a GnRH-responsive element within the rat FSHβ promoter containing an E-box and partial cAMP response element site that are bound by the basic helix loop helix transcription factor family members, upstream stimulating factor (USF)-1/USF-2, and the basic leucine zipper member, cAMP response element-binding protein (CREB), respectively. Expression studies with CREB, USF-1/USF-2, and activating protein-1 demonstrated that the USF transcription factors increased basal transcription, an effect not observed if the cognate binding site was mutated. Conversely, expression of a dominant negative CREB mutant or CREB knockdown attenuated induction by GnRH, whereas dominant negative Fos or USF had no effect on the GnRH response. GnRH stimulation specifically induced an increase in phosphorylated CREB occupation of the FSHβ promoter, leading to the recruitment of CREB-binding protein to enhance gene transcription. In conclusion, a composite element bound by both USF and CREB serves to integrate signals for basal and GnRH-stimulated transcription of the rat FSHβ gene.
Chemisorption of atomic oxygen on Pt(1 1 1) and Pt/Ni(1 1 1) surfaces

Abstract Using density functional theory (B3LYP functional) we systematically studied Pt/Ni alloy clusters (⩽44 atoms) and found that the Pt/Ni(1 1 1) alloy surface prefers the bulk structure (Pt 3 Ni crystal), without showing surface segregation. This leads to an ordered surface with each Ni surrounded by 6 Pt atoms. We then examined the oxygen chemisorption at all surface sites and found strongest binding at a FCC site (2 Pt and 1 Ni atom, 3.50 eV). On pure Pt(1 1 1) oxygen is most stable (3.28 eV) at the FCC site formed by three Pt atoms. This finally leads to a channel-like mobility of oxygen on the alloy surface.
Spine Modifications Associated with Long-Term Potentiation

Modification of neuronal connections is essential for the development of the nervous system and learning and memory functions of the mature brain. Structural modifications, such as modification of dendritic spines where the modified synapses reside, accompany and may even be required for these functional modifications. Recent advances in fluorescence microscopy, coupled with molecular approaches, prompted a rapid advance in the authors’ understanding of spine remodeling associated with synaptic plasticity, especially long-term potentiation. In this article, they review recent progress in this field, with focus on the potential functions of spine remodeling and key issues to be resolved.
MORPHOLOGY, ONTOGENY, AND PHYLOGENETICS OF THE GENUS POSEIDONAMICUS (OSTRACODA: THAEROCYTHERINAE)

Abstract The ostracode genus Poseidonamicus has been widespread and abundant in deep-sea sediments since the Eocene. Despite its prominent role in a number of evolutionary studies, species identification in this genus is often difficult and phylogenetic relationships among its species are not well understood. Here I present the findings from a comprehensive study of this genus with the purpose of discovering novel phylogenetic characters and clarifying species relationships. I briefly describe the adult carapace and trace some of the major morphological changes that occur over the last several instars. I focus particular attention on the arrangement of fossae in the reticulate mesh; these features have been shown in other ostracodes to correspond to underlying epidermal cells. I describe the development of fossae in the region posterior to the adductor muscle scars, and hypothesize a sequence of specific cell divisions to account for the addition of fossae over ontogeny. Phylogenetic characters were deriv...
RF Magnetron Sputtered Ba0.96Ca0.04Ti0.84Zr0.16O3 Thin Films For High Frequency Applications

Perovskite ferroelectric thin films in the paraelectric state exhibit outstanding dielectric properties, even at high frequencies (>1 GHz). The tunable dielectric constant of ferroelectric thin films can be used to design frequency and phase agile components. High dielectric constant thin film ferroelectric materials in the paraelectric state have received enormous attention due to their feasibility in applications such as decoupling capacitors and tunable microwave capacitors; the latter application has been fueled by the recent explosion in wireless and satellite communications. This paper reportsBa0.96Ca0.04Ti0.84Zr0.16O3 (BCTZ) thin films that were deposited on Pt electrodes using radio frequency magnetron sputtering at a low (450 °C) substrate temperature. Sputtered thin film BCTZ at low substrate temperature is compatible with conventional integrated circuit technology. The structural characterization of the deposited films was performed by x-ray diffraction. The electrical characterization of the films was achieved by capacitance-voltage, current-voltage, and S-parameter (via vector network analyzer) measurements. In addition, the effect of post annealing on the deposited films was investigated. A detailed understanding of both their processing and material properties is discussed for successful implementation in high frequency applications.