cssi/SciSciGPT-SciSciNet huggingface dataset:
Moments in Constructivism: How Does Accepting Failures Allow Us To Examine Our Teaching?

This paper examines the past teaching experiences of four chemistry instructors who would ultimately like to be considered successful in their classroom endeavors. In defining success, each of these teachers point to student learning as examples of their achievement. This was not always the case. Intermittently, each teacher taught as they were taught, focusing solely on content, using other people’s curricula, and worried exclusively about their performance as instructors in the classroom. Although each of these instructors are now selfproclaimed constructivists, they continue to struggle with what the term means empirically, how it actually manifests itself in their classrooms, and how they can adequately measure the achievement of their students. Through the course of this selfexamination, each began to recognize many of the successes and failures that occurred as they became constructivist educators. Each independently noted that the transformation from what they were to what they would like to be is an on-going process; the ultimate goal of teaching should focus exclusively on students’ learning. This paper is not a litany of rosy successes, nor is it a string of miserable failures. It is the description of their classrooms, of who they are, and who they would like to be.
Reverse Achilles Tendon Allograft Technique for Anterior Cruciate Ligament Reconstruction

Abstract Because of the increasing popularity of allograft anterior cruciate ligament (ACL) reconstructions, the technical difficulties with posterior bone loss in revision ACL surgery, and the limited supply of bone-patellar tendon-bone donor grafts, we have developed a technique using a reversed Achilles tendon allograft to reconstruct the ACL-deficient knee. This technique allows for bony tibial fixation with an interference screw by rotating the graft 180° and optimizing soft-tissue fixation at the femur with an EndoButton CL (Smith & Nephew, Andover, MA). Short-term follow-up (average, 26.4 weeks) of 10 patients undergoing the reversed Achilles technique has shown excellent results, with Lysholm scores between 91 and 100 and 84 and 90 in 8 of 10 and 2 of 10 patients, respectively. Objective stability assessments, including the Lachman test, anterior drawer, and pivot-shift tests, were also encouraging. Reverse Achilles tendon allografts can be excellent alternatives for ACL reconstruction when bone-patellar tendon-bone grafts are not indicated.
High critical current density of YBCO coated conductors fabricated by inclined substrate deposition

Abstract Inclined substrate deposition (ISD) has great potential for rapid production of high-quality template layers for YBCO-coated conductors. We have grown biaxially textured magnesium oxide (MgO) films on metallic substrates by ISD at deposition rates, 20–100 A/s. Scanning electron microscopy of the ISD MgO films showed columnar grain structures with a roof-tile-shaped surface. X-ray diffraction and pole figure analysis revealed that the c -axis of the ISD MgO is tilted at an angle with respect to the substrate normal. A full width at half maximum (FWHM) of ≈10° was observed in the φ -scan for MgO films. Yttria-stabilized zirconia (YSZ) and ceria (CeO 2 ) buffer layers were epitaxially grown on ISD MgO by pulsed laser deposition (PLD) prior to YBCO deposition by PLD. The YBCO films grown on YSZ/CeO 2 buffered ISD MgO substrates were biaxially aligned with the YBCO c -axis normal to the substrate surface. A critical current density of J c >1.2×10 6 A/cm 2 was measured at 77 K in self-field.
The relations between knowledge, search strategy, and performance in unaided and aided information search

Information search is a critical step in resolving complex issues in many different decision-making domains. This study examines the relations between knowledge, search strategy, and performance in both unaided and aided information search. The results of an experiment indicates that (a) task-relevant knowledge is directly related to performance in aided but not in unaided information search; (b) in unaided information search, search strategy mediates the relation between knowledge and performance; that is, knowledge indirectly affects performance through its effect on search strategy; and (c) an information search aid moderates both the relation between knowledge and search strategy and the relation between search strategy and performance. These findings highlight the importance and the roles of task-relevant technical knowledge and search strategy in explaining information search performance and are most likely to apply to complex, knowledge-intensive domains in which decision makers search large databases to resolve issues.
Theoretical topics in FRBR

IFLA's Functional Requirements for Bibliographic Records (FRBR) presents a compelling and influential conceptual model of the “bibliographic universe”. Given FRBR's scope and influence it is surprising that it has received so little attention from the information science research community. This panel is intended to convene that discussion. Four panelists will raise a variety of issues, focusing primarily on theoretical topics.
Genetic analysis of bipartite geminivirus tissue tropism.

The bipartite geminiviruses bean golden mosaic virus (BGMV), cabbage leaf curl virus (CabLCV), and tomato golden mosaic virus (TGMV) exhibit differential tissue tropism in Nicotiana benthamiana. In systemically infected leaves, BGMV remains largely confined to vascular-associated cells (phloem-limited), whereas CabLCV and TGMV can escape into the surrounding mesophyll. Previous work established that TGMV BRi, the noncoding region upstream from the BR1 open reading frame (ORF), is required for mesophyll invasion, but the virus must also contain the TGMV AL23 or BL1/BR1 ORFs. Here we show that, in a BGMV-based hybrid virus, CabLCV AL23 also directed efficient mesophyll invasion in conjunction with TGMV BRi, which suggests that host-adaptation of AL23 is important for the phenotype. Cis-acting elements required for mesophyll invasion were delineated by analyzing BGMV-based hybrid viruses in which various parts of BRi were exchanged with those of TGMV. Interestingly, mesophyll invasion efficiency of hybrid viruses was not correlated with the extent of viral DNA accumulation. In conjunction with TGMV AL23, a 52-bp region of TGMV BRi with sequence homology to DNA A was sufficient for mesophyll invasion. This 52-bp sequence also directed mesophyll invasion in combination with the TGMV BL1/BR1 ORFs. Overall, these results are consistent with a model for mesophyll invasion in which AL2 protein, in association with host factors, acts through the 52-bp region in TGMV BRi to affect expression of the BR1 gene.
Relationship of sleep to pulmonary function in mucopolysaccharidosis II.

Objective To study the sleep characteristics, pulmonary function, and their relationships in an enzyme naive population of patients with mucopolysaccharidoses (MPS) II (Hunter syndrome). Study design The analyzed subjects (30 patients with MPS II with a median age of 9 years) had been enrolled in an MPS II natural history study and a phase I/II enzyme replacement clinical study in which they underwent standard polysomnography including spirometry and plethysmography, if cooperative. Descriptive statistics and nonparametric correlation were performed for demographic, sleep, and pulmonary function variables. Results Median apnea-hypopnea index was 6.4, with obstructive sleep apnea observed in 27/30 subjects. Sleep architecture was characterized by diminished rapid-eye movement sleep duration (median 13%), and decline in sleep efficiency and slow-wave sleep duration in older individuals. Oxygen desaturation below 90% occurred in 26/30 subjects, and hypoventilation above 50 Torr occurred in 11/23 subjects with accurate end-tidal carbon dioxide recordings. Of 15 subjects with reliable spirometry, median forced expiratory volume in 1 second was below 80% predicted in 12/15 subjects. Forced expiratory volume in 1 second in percent-predicted was inversely related to apnea-hypopnea index and increase from baseline end-tidal carbon dioxide (P = .023, rs= −0.58), (P Conclusion Sleep in MPS II is characterized by obstructive sleep apnea, altered sleep architecture, and impaired gas exchange. Sleep disruption is related to daytime pulmonary function, thus both systems should be evaluated when sleep abnormalities are suspected.
Managed mental health care : Conflicts of interest in the provider/client relationship

What is a conflict of interest? It seems such a simple question (after all, everybody has interests). You might respond that it is a personal kind of moral conflict that entails obligations, divided loyalties, and may include legal implications. You might be quick to point out that 'conflicting interests' (e.g., "I like to dance all night and I also like to read all night") are quite different from a 'conflict of interests ' (e.g., "two people are drowning at the same time and I can only save one of them; whom will I save the scientist, whose work benefits society, or the rich man, whose largesse benefits me?"). And you might add that even though a conflict of interest may prejudice action, it is not in itself an act and does not ensure disloyalty (Rodwin, 1993). Typically, we divide provider/client conflicts into two categories: one, a provider's personal interests (often economic) in conflict with the interests of the client, and two, provider's obligations that may be
Identity, Migration, and the Arts: Three Case Studies of Translocal Communities

For marginalized populations separated from their homelands, the arts are one of the most effective ways by which groups negotiate their identities at the crossroads of various cultures and influences. Through both hybridized and traditional artistic presentations, translocal and transnational communities engage the issues of identity in ways that renegotiate, challenge, and define the unique characteristics that make them who they are. This article examines three distinct cases of translocal populations as well as the ways by which the groups’ artistic activities help to inform a larger reconstruction of community presence and solidarity. Specifically, these three models focus on theater performances by Sudanese “Lost Boys” living in Syracuse, New York; visual art representations by Cuban exiles in Miami; and flamenco musical initiatives by Gitanos in southern Spain. While such examples are not meant to provide a formula by which translocal populations adapt and engage artistic representations, they none...
Validity of clusters formed by graph-theoretic cluster methods

Abstract Let P be a finite set of objects to be classified, and let G be a loopless labeled undirected graph, with point set P , in which two points are adjacent if the objects they represent are similar with respect to a specified criterion. A cluster method is simply a particular function ϱ that maps p into a set ϱ( G ) of subsets of P , the clusters associated with G . In this paper I describe graph-theoretic criteria to measure the validity or relative significance of clusters formed by such methods. Using several of these criteria, I classify a sequence of flat cluster methods in which the notions of cluster are based on various graph-theoretic concepts of internal coherence. Basic issues of cluster validity are illustrated by examples using Jardine and Sibson's B k flat cluster methods.
The toroidal coll planet centrifuge without rotating seals applied to countercurrent chromatography

Abstract A new high-performance, compact table top coil planet centrifuge is introduced. The apparatus holds a long fine coiled column wound on a large diameter drum-shaped holder. Synchronous planetary motion of the holder not only allows continuous elution without the use of rotating seals, but also provides an ideal acceleration field which enables retention of the stationary phase and efficient mixing of the two solvent phases in the coiled column. Potential capabilities of the apparatus was demonstrated on separation of a set of dinitrophenyl amino acids using a two-phase solvent system composed of CHCl3/CH3COOH/0.1 n HCl at a 2/2/1 volume ratio. With a column consisting of 8500 helical turns partition efficiencies ranging between 6000 and 2000 theoretical plates were attained. The capability of the present scheme may be extended to partition of cells and macromolecules with polymer phase systems and to cell elutriation with physiological solutions.
THE DUTCH MONETARY ENVIRONMENT DURING TULIPMANIA

W hen the economics profession turns its attention to financial panics and crashes, the first episode mentioned is tulipmania. In fact, tulipmania has become a metaphor in the economics field. Should one look up tulipmania in The New Palgrave: A Dictionary of Economics, a discussion of the seventeenth century Dutch speculative mania will not be found. Guillermo Calvo (1987, p. 707), in his contribution to the Palgrave instead defines tulipmania as: "situations in which some prices behave in a way that appears not to be fully explainable by economic 'fundamentals. '" Brown University economist, Peter Garbcr, is considered the modern tulipmania expert. In Garber's view, tulipmania was not a mania at all, but is explainable by market fundamentals. The explosive increases in the price of tulip bulbs, Garber says, can be explained by supply and demand factors. Rare bulbs were hard to reproduce and in the greatest demand. Thus, rare bulbs tended to rise in price. However, this does not explain the price history of the common Witte Croonen bulb, that rose in price twenty-six times in January 1637, only to fall to one-twentieth of its peak price a week later (Garber 1989, p. 556). Garber admits in more recent works (2000, p. 80) that the "increase and collapse of the relative price of common bulbs is the remarkable feature of this phase of the speculation." Garber in his own words "would be hard pressed to find a market fundamental explanation for these relative price movements." In addition to his ~'fundamentals" argument, Garber (1990b, p. 16) points to the Bubonic Plague as a possible cause of tulipmania. "Although the plague outbreak may be a false clue, it is conceivable that a gambling binge tied to a drinking game and general carousing may have materialized as a response to the death threat." This fatalistic extension of Keynes's "animal spirits" hypothesis is less than convincing.
Asymptomatic severe mitral valve regurgitation: observation or operation?

Management of patients with mitral valve regurgitation (MR) has changed dramatically over the past 20 years; this change is largely attributable to 3 factors. First, there have been significant improvements in operative techniques that have led to predictable and durable results after valve repair. In current practice at our clinic, >95% of patients with pure MR caused by degenerative diseases have valve repair rather than prosthetic replacement, and with modern, simplified methods of leaflet repair and annuloplasty, the risk of reoperation after correction of MR is no greater than that after mitral valve replacement.1 Article p 797 The second major shift in mitral valve disease is the change in pathology and pathophysiology of MR. In current practice, almost 80% of patients having mitral valve operations have pure regurgitation rather than valve stenosis or mixed regurgitation and stenosis, and the cause is most often degenerative or myxomatous disease; there is a declining frequency of postinflammatory disease in North America and many other areas of the world. The third important change in the management of patients with mitral valve disease is the better understanding of the natural history of MR, which has been made possible by both detailed natural history studies and improved techniques of 2-dimensional and Doppler echocardiography.2–4 The article by Kang et al5 in this issue of Circulation provides important new and confirmatory information on the outcome of asymptomatic patients with severe MR. Before the 1990s, most clinicians viewed MR as a relatively benign condition, and surgery was reserved for patients who were severely symptomatic or failed medical management.6,7 Reluctance to proceed with operation was related to the likelihood of prosthetic valve replacement and to the notion that asymptomatic patients with severe MR were a …
Homelessness, Violence Exposure, and School Participation among Urban Adolescent Mothers.

Using a risk and resilience framework, this exploratory study examines the relationships between homelessness, exposure to multiple types of violence, and school participation within a survey sample of poor adolescent mothers living in an urban setting. Participants who were homeless either currently or historically were compared with participants who had never been homeless in terms of rate of violence exposure and school participation. Social support was analyzed as a moderator of the effects of violence exposure on the odds of homelessness, while positive attitude toward school was assessed as a moderator of homelessness on school participation. Results from MANOVA indicate that participants who report homelessness have significantly higher rates of exposure to violence and significantly lower rates of social support, positive attitude toward school, and school participation in comparison with participants who have never been homeless. Regression analyses indicate that violence exposure, moderated by social support, plays a significant contributing role in participants' odds of ever being homeless. Experiencing homelessness, in turn, is a significant contributor to reduced school participation. © 2007 Wiley Periodicals, Inc. J Comm Psychol 35: 639–654, 2007.
On the supramolecular organization of gramicidin channels. The elementary conducting unit is a dimer.

The question, whether the conducting channels formed by the linear gramicidins are dimers (as is generally believed) or tetramers (as has been recently proposed [Stark G., M. Strassle, and Z. Takacz. 1986. J. Membr. Biol. 89:23–37; Strassle, M., G. Stark, M. Wilhelm, P. Daumas, F. Heitz, and R. Lazaro. 1989. Biochim. Biophys. Acta. 980:305–314]) has been addressed in single-channel experiments. The experimental approach was based on the ability of electrophysiological (single-channel) experiments to resolve the number of hybrid channel types that could form between gramicidin A or C and O-pyromellityl-gramicidin A or C (in which a pyromellitic acid residue has been esterified to the ethanolamine-OH group [Apell, H.-J., E. Bamberg, H. Alpes, and P. Lauger. 1977. J. Membr. Biol. 31:171–188]). The presence of the bulky, negatively charged pyromellityl group at the channel entrances endows the hybrid channels with characteristically different features and thus facilitates the resolution of the different hybrid channel types. Only two hybrid channel types were detected, indicating that the conducting channels are membrane-spanning dimers. There was likewise no evidence for lateral association between conducting channels and nonconducting monomers. These results can be reconciled with those of Stark et al. (op. cit.) if gramicidin channel formation involves a (slow) folding into beta 6.3-helical monomers followed by the dimerization step.
SPR criteria for uncertain rational matrices via polynomial positivity and Bernstein's expansions

The main purpose of this brief is to convert the strict positive real (SPR) conditions for rational matrices to conditions involving only positivity of polynomials. The polynomial formulation provides efficient SPR criteria for matrices with uncertain interval parameters. To establish the robust SPR property, it is sufficient to test positivity of only three uncertain polynomials regardless of the order of the matrix. The most interesting feature of the proposed polynomial formulation is that the coefficients of uncertain matrices are allowed to have polynomic uncertainty structure. This generality is easily handled by using the Bernstein expansion algorithm. The efficiency of the proposed polynomial approach is illustrated by testing absolute stability of a MIMO Lur'e-Postnikov system having interval parameters.
Characterization and functions of the whitefly egg pedicel

For the silverleaf whitefly, Bemisia argentifolii (Bellows and Perring) (Homoptera: Aleyrodidae), scanning and transmission electron microscopic techniques were used to observe the characteristics of egg oviposition into both plant cells/tissues and artificial membranes, and to document the morphology of mature egg pedicles removed from the ovaries of females. The exterior of the distal portion of the pedicel consisted of a tangled array of fibrous structures (0.2-0.3 microm in diameter) that constituted about 20-25% of the outer diameter of the pedicel. The attachments of the fibers to the core of the pedicle suggested that the pedicel functions as the collector and conduit for water (vapor), and perhaps solute movement into the egg. Silverleaf whitefly eggs on membranes were incubated at various levels of relative humidity and the eggs were scored for egg hatch. At 98-100% rh, the percentage egg hatch was 86-98%. At lower humidity ranges of 0-20, 55-65, and 75-85% rh, none of the eggs hatched. Media (solute) uptake by silverleaf whitefly egg pedicels was determined by exposing the pedicel side of eggs oviposited on membranes to media solutions containing the high molecular weight polysaccharide, [(14)C]-inulin. Solute uptake by the pedicel and movement into developing silverleaf whitefly eggs were demonstrated using [2-(14)C]-acetate, and assaying for radioactivity in hatched nymphs. These studies, using exposure of pedicels to relative humidity and radiolabeled materials, demonstrate that whitefly egg hatch is dependent upon water uptake by the pedicel, and that the pedicel has the ability to transport solutes into the developing egg.
Effect of low-pressure argon plasma on metal vaporization rates

Abstract Rates of vaporization of liquid iron and copper drops were determined both in the presence and the absence of a low-pressure argon plasma. The vaporization rates of pure metal drops and metal drops that were doped with small amounts of oxygen or sulfur were found to decrease when plasma was present. The results are consistent with the presence of a charge distribution field in close proximity of the interface.
MR Contrast Due to Microscopically Heterogeneous Magnetic Susceptibility: Numerical Simulations and Applications to Cerebral Physiology

We calculate the effects of subvoxel variations in magnetic susceptibility on MR image intensity for spin-echo (SE) and gradient-echo (GE) experiments for a range of microscopic physical parameters. The model used neglects the overlap of gradients from one magnetic inclusion to the next, and so is valid for low volume fractions and weak perturbations of the magnetic field. Transverse relaxation is predicted to deviate significantly from linear exponential decay in both SE and GE at a particle radius of 2.5 microns. Calculated changes in transverse relaxation rates for SE and GE increase linearly with volume fraction of high-susceptibility regions of 5 microns diameter, but increase with about the 3/2 power of volume fraction of regions with 15 micron spacing between centers. This sensitivity to the actual size and spacing of magnetized regions may allow them to be measured on the basis of contrast. without being resolved in images. GE and SE decay rates are approximately twice as sensitive to long cylinders of 5 microns diameter than to spheres of the same size, for diffusion constants of 2.5 micron 2/ms. Calculated changes in transverse decay rates increase with approximately the square of field and susceptibility variation for 5-microns spheres and a diffusion constant of 2.5 microns 2/ms. This exponent is smaller for cylindrical magnetized regions of the same size, and also depends on the diffusion constant. We discuss possible applications of our theoretical results to the analysis of the effects of high-susceptibility contrast agents in brain. Experimental data from the literature are compared with calculated signal changes according to the model. The monotonic dependence of decay rates on the volume of distribution of the contrast agent suggests that cerebral blood volume and flow could be measured using MR contrast.
Food intake frequencies of food co-op shoppers

Abstract We surveyed shoppers in one cooperative food store and one commercial supermarket in each of three cities to determine whether shoppers' food intake differed according to the market in which they shopped. The cities were Corvallis, Oregon; Davis, California; and Ithaca, New York. Shoppers completed questionnaires indicating how often they consumed each of 28 foods. In all locations, co-op shoppers showed less frequent consumption of meat products and refined grain products but more frequent consumption of certain produce items and specialty foods such as tofu and alfalfa sprouts. These practices are in keeping with the orientation of the nutrition education programs usually found in this type of cooperative store.
Factors Influencing the Transition from Metastable to Stable Pitting in Single-Crystal Beryllium

The pitting potential (E pit ) of single-crystal beryllium in 0.01 M sodium chloride decreased with crystallographic orientation in the order (0001) > (1010) > (1120). Orientations which were associated with the lowest E pit, (1010) and (1120), were characterized by crystallographically oriented parallel plates of unattacked Be on the pit interior and square pit walls. While pit geometries in the (0001) surface appeared to be random, corrosion propagation was often in the (1010) and (1210) families of directions. Potentiostatic current/time data revealed that metastable pitting was characterized by two types of transients: (i) transients with a lifetime <1 s, similar in shape to the current/time data observed in the repassivation process, and (ii) transients whose lifetimes lasted 5-140 s and were associated with physical damage on the sample surface. The nucleation frequency of repassivation events was directly proportional to passive current density and inversely proportional to applied anodic potential. Although the frequency and magnitude of damage events increased with increasing applied anodic potential for any given orientation the total accumulated damage was greatest for orientations with the highest E pit . Prepassivation resulted in a decrease in the frequency of repassivation events but had only minimal effect on the frequency and magnitude of the damage events. The results are discussed in terms of physical bulk metal properties as well as critical pitting environments (i,e., ohmic and mass transport models).
Fine structural analysis of the conjunctival papillae in the chick embryo: a reassessment of their morphogenesis and developmental significance.

Development and regression of the conjunctival papillae have been examined with both light and electron microscopy. The fibrous strands which extend from the papillae to the mesenchyme of the pre-ossicular plate have been identified as collagen. Furthermore, the initial deposition of collagen fibrils has been shown to occur within channels between cells of the basal epithelium during stages 2 and 3. Bundles of collagen fibrils extend continuously from the uppermost portions of the cavity of the papilla to the mesenchyme of the condensing pre-ossicular plate during stage 5. Degeneration is localized in a small area of the papilla during stages 3 and 4 but spreads throughout the mass during stage 5. Late in stage 5, necrotic epithelial cells are sloughed into the cavity of the papilla from its basal layer. These findings are discussed in relation to earlier light microscopic and experimental studies which have shown the papillae to be required for the subsequent development of the scleral ossicles in the subjacent mesenchyme.
A large obstructive parapelvic cyst: challenging diagnosis and management.

A 56-year-old woman with a remote history of nephrolithiasis presented with a right-sided flank pain. Her electrolytes and urinalysis were within normal limits. A renal sonogram revealed a massive right hydronephrosis consistent with ureteropelvic junction obstruction. An abdominal computed tomography scan confirmed this erroneous diagnosis (Figure 1). Unexpectedly, a retrograde pyelogram demonstrated a large obstructive parapelvic cyst (Figure 2). The patient underwent a percutaneous nephroscopy. A nephrotomy was created into the renal cyst itself, and clear fluid was aspirated for cytologic evaluation. An inspection of the cyst wall was performed with a rigid nephroscope and showed no evidence of excrescences, tumors, or other abnormalities (Figure 3). Endoscopic fulguration of the entire cyst was performed with a resectoscope and a rollerball electrode under low voltage. Cystoscopic examination of cyst aspirate revealed no malignant cells. The patient tolerated the procedure well, and a follow-up computed tomography scan confirmed partial resolution of hydronephrosis (Figure 4). Parapelvic cysts present a challenging diagnosis and may be missed on ultrasound and computed tomography scan. Management involves retrograde ureterorenoscopy, antegrade percutaneous nephroscopy, or laparoscopy. Although all three methods are minimally invasive and effective, the retrograde approach is limited by the size and location of the cyst. Laparoscopy is associated with multiple port sites, extensive dissection, and technical difficulty. The percutaneous transparenchymal endocystolysis was successfully used in this case.
Towards privacy preserving access control in the cloud

It is very costly and cumbersome to manage database systems in-house especially for small or medium organizations. Data-as-a-Service (DaaS) hosted in the cloud provides an attractive solution, which is flexible, reliable, easy and economical to operate, for such organizations. However security and privacy issues concerning the storage of the data in the cloud and access via the Internet have been major concerns for many organizations. The data and the human resources are the life blood of any organization. Hence, they should be strongly protected. In this paper, we identify the challenges in securing DaaS model and propose a system called CloudMask that lays the foundation for organizations to enjoy all the benefits of hosting their data in the cloud while at the same time supporting fine-grained and flexible access control for shared data hosted in the cloud.
Effect of Polyethylene Glycol on the Microstructure of Freeze‐Cast Alumina

Freeze casting has been used to process a range of ceramics with oriented pore structures, and soluble polymers are often used to improve the strength of the material before sintering. This study examined the effect of polyethylene glycol (PEG) on the three distinct microstructural scales, which include the colony size, the pore size, and the secondary dendrite spacing. The results showed that the trends in pore size and secondary dendrite spacing were consistent with the effect of constitutional supercooling on the growth of ice crystals. In contrast, the effect of PEG on colony size appeared to be more pronounced and may reflect preferential adsorption on the prism faces of the growing ice crystals. For both alumina and PEG content, the observed effects were very much dependent on the temperature of the chill surface used in casting.
Freeze-fracture studies on the cockroach hemocyte membrane complex: symmetric and asymmetric membrane particle distributions.

Freeze-fracture studies were conducted on the membranes of normal cockroach hemocytes. The plasmalemma is asymmetric with the A fracture face containing 80–100 A membrane intercalated particles at a concentration of ∼2500/μ2. The B fracture face contains 120–150 A particles with a relatively low density (∼800/μ2). The nuclear envelope displays an asymmetry with the A fracture face containing ∼1500 particles/μ2 and the B face containing ∼300/μ 2. No significant particle size differences were observed in nuclear envelope fracture faces. Two types of symmetric membranes were also found in these cells. Both A and B fracture faces of the membrane surrounding the numerous cytoplasmic inclusion bodies contain particle sizes and concentrations similar to the B face of the plasmalemma. A second type of symmetry was observed in cells apparently engaged in “exocytosis”. Vesicles (∼0.1 μD) from this process were completely particle free on both fracture faces. Such particle free vesicles could be found in the cytoplasm, attached to the plasmalemma, or completely separated from the cell.
Algorithms for accurate 3D registration of neuronal images acquired by confocal scanning laser microscopy

This paper presents automated and accurate algorithms based on high-order transformation models for registering three-dimensional (3D) confocal images of dye-injected neurons. The algorithms improve upon prior methods in several ways, and meet the more stringent image registration needs of applications such as two-view attenuation correction recently developed by us. First, they achieve high accuracy ( approximately 1.2 voxels, equivalent to 0.4 micro m) by using landmarks, rather than intensity correlations, and by using a high-dimensional affine and quadratic transformation model that accounts for 3D translation, rotation, non-isotropic scaling, modest curvature of field, distortions and mechanical inconsistencies introduced by the imaging system. Second, they use a hierarchy of models and iterative algorithms to eliminate potential instabilities. Third, they incorporate robust statistical methods to achieve accurate registration in the face of inaccurate and missing landmarks. Fourth, they are fully automated, even estimating the initial registration from the extracted landmarks. Finally, they are computationally efficient, taking less than a minute on a 900-MHz Pentium III computer for registering two images roughly 70 MB in size. The registration errors represent a combination of modelling, estimation, discretization and neuron tracing errors. Accurate 3D montaging is described; the algorithms have broader applicability to images of vasculature, and other structures with distinctive point, line and surface landmarks.
Cysteine/cystine redox signaling in cardiovascular disease

Extracellular thiol/disulfide redox environments are highly regulated in healthy individuals. The major thiol/disulfide redox couple in human plasma is cysteine (Cys) and its disulfide form, cystine (CySS). Oxidation of this redox couple, measured as a more positive steady-state redox potential (E(h)), is associated with risk factors for cardiovascular disease (CVD), including aging, smoking, obesity, and alcohol abuse. Rodent and vascular cell studies show that the extracellular redox state of Cys/CySS (E(h)CySS) can play a vital role in controlling CVD through proinflammatory signaling. This inflammatory signaling is regulated by cell-surface protein redox state and involves mitochondrial oxidation, nuclear factor-κB activation, and elevated expression of genes for monocyte recruitment to endothelial cells. Gene array and proteomics studies reveal the global nature of redox effects, and different cell types, e.g., endothelial cells, monocytes, fibroblasts, and epithelial cells, show cell-specific redox responses with different phenotypic traits, e.g., proliferation and apoptosis, which can contribute to CVD. The critical nature of the proinflammatory redox signaling and cell biology associated with E(h)CySS supports the use of plasma levels of Cys, CySS, and E(h)CySS as key indicators of vascular health. Plasma redox-state-based pharmacologic interventions to control or improve E(h)CySS may be effective in preventing CVD onset or progression.
Scattering from coated random rough surfaces characterized by the Mueller matrix

ABSTRACT The Mueller matrix completely characterizes scattered electromagnetic waves. It relates the incident to the scatteredStokes vectors. The Mueller matrix which contains intensity and relative phase data is very useful for remote sensing. The Mueller matrix, characterizing scattering from uniformly coated two-dimensional random rough surfaces, isobtained from full wave solutions for the scattered fields. The uniformly coated two-dimensional random roughsurfaces are assumed to be homogeneous, and isotropic with a Gaussian surface height joint probability densityfunction. The diffuse, incoherent and coherent contributions to the Muller matrix elements are evaluated. The Mueller matrix elements are more sensitive to the changes in the rms slope than to changes in the rms height. The element M34 = —M43 (backscatter) is most senstive to variations in the thickness of the coating layer. This result could be used to estimate the thickness of the coating material. The magnitudes of the Muller matrix elements
The global dimension of an f-ring via its space of minimal prime ideals

This article examines hereditary f-rings, after first characterizingthe hereditary von Neumann regular commutative rings as those for which the space of maximal ideals is hereditarily paracompact. It is shown that if C ( X , Z ) , the ring of integer-valued continuous functions on a zero-dimensional space X, is hereditary, then X is finite. This is shown two ways; once as a consequence of the following: if A is any singular archimedean f-ring, then A/2A is a boolean ring, and gd(A) >= gd(A/2A)+ 1 , where gd(A) stands for the global dimension of A. As a consequence of this it is also shown that if A is a singular archimedean f-ring and gd(A) <= 2, then Min(A), the space of minimal prime ideals is hereditarily paracompact. The paper concludes with a calculation of the global dimension of a mihereditary singular archimedean f-ring A, in which the cellularityof Min(A) is “much less” than |A| if finite, it is k+2, where Nk = |A|.
Nicotine for Colitis -- The Smoke Has Not Yet Cleared

As the search for the cause of inflammatory bowel disease continues,1 the association between cigarette smoking and a more favorable clinical course in ulcerative colitis remains the sole epidemiol...
Angiotensin-responsive adrenal glomerulosa cell proteins: characterization by protease mapping, species comparison, and specific angiotensin receptor antagonists

Angiotensin II (AngII)-stimulated aldosterone synthesis is mediated by the AngII type 1 (AT1) receptor and requires ongoing protein synthesis. Hormonally-stimulated turnover of a family of 28- to 30-kDa proteins (p30, or steroidogenic acute regulatory proteins) has been linked to enhanced steroid synthesis in several tissues. Our previous work showed that AngII, dibutyryl cAMP, potassium, and atrial natriuretic peptide affected labeling of a group of eight proteins (four of 28 kDa and four of 30 kDa) in bovine adrenal glomerulosa cells. This report extends our findings in three ways: 1) The eight [35S]-methionine-labeled p30 proteins in bovine cells were compared with each other by chymotryptic peptide mapping. Similarity in maps indicated that the eight proteins share a common primary structure. 2) Dibutyryl cAMP treatment of rat adrenal glomerulosa cells affected the levels of four 28-kDa proteins and one 35-kDa protein, whereas AngII affected two of the 28-kDa proteins. There were no responsive 30-kDa proteins in rats comparable with those seen in bovine cells. These results indicate a species difference in the affected proteins. 3) The AT1 receptor antagonist, losartan, inhibited the effects of AngII on aldosterone synthesis and turnover of the p30 proteins in bovine adrenal glomerulosa cells. PD123319, an antagonist specific for the AngII type 2 receptor, did not block AngII-stimulated aldosterone synthesis and had much less effect on p30 protein labeling than did losartan. These results add to the growing body of evidence that this family of p30 or steroidogenic acute regulatory proteins plays a role in the acute regulation of steroidogenesis by a wide variety of stimulatory hormones in several tissues and species. In addition, losartan's inhibition of AngII's effects on the p30 proteins is consistent with a key role for these proteins in processes linking occupation of the AT1 receptor to stimulation of aldosterone synthesis.
Feature Extraction and Object Recognition in Multi-Modal Forward Looking Imagery

The U. S. Army Night Vision and Electronic Sensors Directorate (NVESD) recently tested an explosive-hazards detection vehicle that combines a pulsed FLGPR with a visible-spectrum color camera. Additionally, NVESD tested a human-in-the-loop multi-camera system with the same goal in mind. It contains wide field-of-view color and infrared cameras as well as zoomable narrow field-of-view versions of those modalities. Even though they are separate vehicles, having information from both systems offers great potential for information fusion. Based on previous work at the University of Missouri, we are not only able to register the UTM-based positions of the FLGPR to the color image sequences on the first system, but we can register these locations to corresponding image frames of all sensors on the human-in-the-loop platform. This paper presents our approach to first generate libraries of multi-sensor information across these platforms. Subsequently, research is performed in feature extraction and recognition algorithms based on the multi-sensor signatures. Our goal is to tailor specific algorithms to recognize and eliminate different categories of clutter and to be able to identify particular explosive hazards. We demonstrate our library creation, feature extraction and object recognition results on a large data collection at a US Army test site.
Cholestasis of Pregnancy

Intrahepatic cholestasis (ICP) of pregnancy is a disease that is likely multifactorial in etiology and has a prevalence that varies by geography and ethnicity. The diagnosis is made when patients have a combination of pruritus and abnormal liver-function tests. It is associated with a high risk for adverse perinatal outcome, including preterm birth, meconium passage, and fetal death. As of yet, the cause for fetal death is unknown. Because fetal deaths caused by ICP appear to occur predominantly after 37 weeks, it is suggested to offer delivery at approximately 37 weeks. Ursodeoxycholic acid appears to be the most effective medication to improve maternal pruritus and liver-function tests; however, there is no medication to date that has been shown to reduce the risk for fetal death.
Parents' disclosure of their own concerns to their adolescent children

This study examines middle-aged parents' disclosure about their own lives and current concerns, with their late-adolescent children. Three hundred seventy-two parents of college freshmen, averaging 47 years of age, participated by filling out an anonymous questionnaire that asked about 28 topics, varying in intimacy, of concern to adults. The subjects indicated whether they had discussed each topic with their child, and, if they had, the motivations that prompted them to do so. The data revealed that mothers disclosed more than did fathers, and they were more likely to cite “venting,”“asking advice,” and “seeking emotional support” as reasons for disclosure; fathers were more likely to cite “trying to change his/her behavior” as a rationale for disclosure. Child's gender did not affect disclosure rates, but sons and daughters were disclosed to for different reasons. Divorced parents disclosed more than did parents from continuously intact families, and they cited somewhat different reasons for disclosure.
China's Economic and Political Rise: Implications for Global Terrorism and U.S.–China Cooperation

As a rising power in the international system, China is discovering that, like many states before it, the ascendancy to great power status sometimes entails significant terrorism risks. Recent atta...
A model of healthy aging and motor inhibition in the basal ganglia

The basal ganglia have received a great deal of attention from modeling studies because of their putative role in normal motor function including action selection and sequencing, as well as their distubrances in Parkinson’s disease. However, their interaction is complex, and is thought to be more sophisticated than can be accounted for by simple box and plot diagrams. In the present study, we have examined trial by trial variations in response times in the stop signal task for both young (YA) and older (OA) adults. We compare previously reported YA data [1] with data collected from 18 older adults performing the same task. Unlike YA, the OA do not show a specific pattern of response times that is modulated by stop signal success in the previous trial. Additionally, the OA did not show an effect of inter trial interval (ITI) as was observed in YA. Based on our behavioral data [1], we concluded that a task switching interpretation was the most likely explanation of the YA results. We also compare the electrophysiological data collected during the ITI from OA and YA performing the stop signal task. In YA, the power spectral data revealed a midline frontal theta effect with more desynchronization following a stop signal trial. As in [1], we concluded that this evinced a task set switching interpretation as YA subjects went from a ‘ready to inhibit’ mode to a ‘ready to respond’ mode. In the OA data presented here, we failed to observe a similar frontal theta effect, which was expected given the lack of a behavioral result in the OA subjects. To test hypotheses about the role of the basal ganglia in task switching in young and older adults, we have developed a conductance-based network model of the subthalamic nucleus, internal and external segments of the globus pallidus. The model incorporates cellular properties described in previous modeling studies [3] based on experimental findings. First we establish network properties which lead to patterns of beta activity that are consistent with observed phenomenon in human subjects [2]. Next, we determine which network parameters affect trial to trial variations in response times within the model. Using this approach, we examine how known changes in healthy older adult basal ganglia may affect task performance. Similarly, we discuss the implications for Parkinson’s disease.
Global diversity and distribution of arbuscular mycorrhizal fungi

Arbuscular mycorrhizal (AM) fungi form associations with most land plants and can control carbon, nitrogen, and phosphorus cycling between above- and belowground components of ecosystems. Current estimates of AM fungal distributions are mainly inferred from the individual distributions of plant biomes, and climatic factors. However, dispersal limitation, local environmental conditions,and interactions among AM fungal taxa may also determine local diversity and global distributions. We assessed the relative importance of these potential controls by collecting 14,961 DNA sequences from 111 published studies and testing for relationships between AM fungal community composition and geography, environment, and plant biomes. Our results indicated that the global species richness of AM fungi was up to six times higher than previously estimated, largely owing to high beta diversity among sampling sites. Geographic distance, soil temperature and moisture, and plant community type were each significantly related to AM fungal community structure, but explained only a small amount of the observed variance. AM fungal species also tended to be phylogenetically clustered within sites, further suggesting that habitat filtering or dispersal limitation is a driver of AM fungal community assembly. Therefore, predicted shifts in climate and plant species distributions under global change may alter AM fungal communities.
T-cell subsets in polymyositis.

Distribution of T-cell subsets in the peripheral blood of six patients with polymyositis and one with childhood dermatomyositis was studied using monoclonal antibodies. No difference was noted in the suppressor or helper fractions as compared to normal controls.