cssi/SciSciGPT-SciSciNet huggingface dataset:
Effects of amide side chains on nanoassembly formation and gelation of Fmoc–valine conjugates

Abstract In this work, we have examined the formation of nanoassemblies by self-assembly process using amide derivatives of Fmoc–valine (fluorenylmethyloxycarbonyl-protected valine). The derivatives were synthesized by combining Fmoc–Val with four different linkers (diphenyl amine; hexadecylamine; N 1 , N 4 , N 9 -tris-Boc-spermine and N 1 , N 4 -bis-Boc-spermidine). The materials were allowed to self-assemble into nanoassemblies and their growth and gelation were probed at varying pH values. Secondary structural analysis was carried out using FTIR and CD spectroscopy to shed light into the mechanistic aspects of formation of the assemblies. The morphologies and thermal properties were studied by transmission electron microscopy (TEM), and differential scanning calorimetry (DSC) respectively. Wettability studies using contact angle measurements were carried to examine the hydrophobicity changes of the assemblies due to incorporation of the various amide derivatives. Our results indicate that while stacking interactions between the FMOC moieties played a vital role in the self-assembly process and gelation behavior in all cases, the morphologies were also influenced by the chain length and functionalities of the linkers utilized. The assemblies showed mixed conformations of both alpha-helices and beta-sheets. The materials formed may have a wide range of potential applications from drug delivery to development of tissue engineering scaffolds.
Effects of Thermal Processing on the Enzyme-Linked Immunosorbent Assay (ELISA) Detection of Milk Residues in a Model Food Matrix

Food products and ingredients are frequently tested for the presence of undeclared allergenic food residues (including milk) using commercial enzyme-linked immunosorbent assays (ELISAs). However, little is understood about the efficacy of these kits with thermally processed foods. This study evaluated the performance of three milk ELISA kits with a model food processed by several methods. A model food (pastry dough squares) was spiked with nonfat dry milk at several concentrations. The pastry squares were processed by boiling (100 °C for 2 min), baking (190 °C for 30 min), frying (190 °C for 2 min), and retorting (121 °C for 20 min with 17 psi overpressure). Samples were analyzed with three commercial ELISA kits: Neogen Veratox Total Milk, ELISA Systems β-lactoglobulin, and ELISA Systems casein. The detection of milk residues depended upon the type of processing applied to the food and the specific milk analyte targeted by the ELISA kit. Poor recoveries were obtained in all processed samples (2−10% of exp...
Thermal cure of phenylethynyl‐terminated AFR‐PEPA‐4 imide oligomer and a model compound

The thermal cure reactions of phenylethynyl terminated AFR-PEPA-4 oligomer and a model compound N-phenyl-[4-(phenylethynyl) phthalimide] were investigated. The kinetics analysis of the thermal cure of AFR-PEPA-4 was determined using DSC, with modified DiBenedetto equation. The activation energy of thermal cure reaction of AFR-PEPA-4 oligomer is 34.1 kcal/mol with the kinetic order of one, when the reaction conversion is less than 80%. The activation energy of thermal reaction of N-phenyl-[4-(phenylethynyl) phthalimide] is 41.5 kcal/mol with the kinetic order of 0.95. The cure reaction of AFR-PEPA-4 imide oligomer can be described as a fast first-order reaction stage for the formation of polyenes followed by a slow diffusion-controlled crosslinking reaction stage. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4446–4453, 2006
Glycosaminoglycan synthesis by Wilms' tumor.

Summary: Wilms' tumor contains approximately 1 mg hyaluronic acid and approximately 0.3 mg sulfated glycosaminoglycan per g tissue. Minced tumor and cells cultured from the tumor incorporate labeled acetate and glucosamine into hyaluronic acid and sulfated glycosaminoglycans. A particulate enzyme preparation derived from the tumor catalyzed the transfer of GlcUA or GlcNAc from UDP-GlcUA or UDP-GlcNAc at a rate of approximately 20 nmol/hr/mg protein to produce high molecular weight hyaluronic acid chains. The urine and plasma of a Wilms' tumor patient contained approximately 20 mg hyaluronic acid and 8 mg sulfated glycosaminoglycan/100 ml, respectively. It appears that this higher than normal level of circulating glycosaminoglycan is synthesized by the Wilms' tumor. Speculation: The conversion of normal cells to malignant cells results in changes in regulation of glycosaminoglycan synthesis. Of special interest is the same qualitative change in hyaluronic acid synthesis in Wilms' tumor as observed in SV40-transformed human fibroblasts.
Proposed legislation supports an untested publishing model.

Free access to information is a powerful and alluring concept. Under the “Public Access to Science Act,” recently introduced into the U.S. House of Representatives by Representative Martin O. Sabo (Democrat, Minnesota), papers describing scientific research substantially funded by the U.S.
Nonlinear energy-selective nanoscale modifications of materials and dynamics in metals and semiconductors

Studies of nonlinear, energy-selective material interactions localized at surfaces, heterointerfaces, impurities, and defects in solids are described. Particular reference is made to a new molecular interaction effect caused by transfer of surface energy by low-energy collisions, a new noncontact nonlinear optical method of studying electron and hole dynamics at a heterointerface, and a new approach using a free-electron laser developed at Vanderbilt University to activate hydrogen-passivated dopants in silicon. In each case the unique characteristics of particle and photon beams, optimized for the technology, were used to extend the range of applications of these new energy-selective techniques to solve fundamental and applied problems.
The Channel Kinases TRPM6 and TRPM7 Are Functionally Nonredundant

TRPM7 and its closest homologue, TRPM6, are the only known fusions of an ion channel pore with a kinase domain. Deletion of TRPM7 in DT40 B-lymphocytes causes growth arrest, Mg(2+) deficiency, and cell death within 24-48 h. Amazingly, in analogy to TRPM6-deficient patients who can live a normal life if provided with a Mg(2+)-rich diet, TRPM7-deficient DT40 B-lymphocytes show wild type cell growth if supplied with 5-10 mm Mg(2+) concentrations in their extracellular medium. Here we have investigated the functional relationship between TRPM6 and TRPM7. We show that TRPM7 deficiency in DT40 cells cannot be complemented by heterologously expressed TRPM6. Nevertheless, both channels can influence each other's biological activity. Our data demonstrate that TRPM6 requires TRPM7 for surface expression in HEK-293 cells and also that TRPM6 is capable of cross-phosphorylating TRPM7 as assessed using a phosphothreonine-specific antibody but not vice versa. TRPM6 and TRPM7 coexpression studies in DT40 B-cells indicate that TRPM6 can modulate TRPM7 function. In conclusion, although TRPM6 and TRPM7 are closely related and deficiency in either one of these molecules severely affects Mg(2+) homeostasis regulation, TRPM6 and TRPM7 do not appear to be functionally redundant but rather two unique and essential components of vertebrate ion homeostasis regulation.
Activation of Δ5-3-ketosteroid isomerase of bovine adrenal microsomes by serum albumins

Abstract The Δ 5 -3-ketosteroid isomerase (EC 5.3.3.1) of bovine adrenal microsomes is activated as much as 10- to 20-fold by micromolar concentrations of bovine serum albumin. Comparable activations are observed with the serum albumins of 10 other mammalian species, but are not seen with ovalbumin or conalbumin. Evidence that the activation is attributable to the serum albumins, rather than to a small, firmly-bound ligand, is based on: (1) Failure to remove the stimulatory activity from the albumin by chloroform extraction, dialysis, or gel filtration; (2) Destruction of the activity by heating or by trypsin digestion; (3) Precipitation of the stimulatory activity of bovine serum albumin by specific antibody. Bovine serum albumin induces small decreases in the Michaelis constant for Δ 5 -androstene-3,17-dione, but most of the activational effect reflects an increase in the maximum velocity. Low concentrations of Triton X-100, which are without effect on the isomerase activity, prevent the activation by bovine serum albumin.
An iterative technique for the finite element analysis of near-incompressible materials

Abstract A new preconditioner for the conjugate gradient method applicable to the finite element analysis of near-incompressible finite elasticity is presented. The boundary value problem is discretized with a displacement/pressure mixed formulation.The pressure degrees of freedom are eliminated at the element level. The problem is linearized using a Newton—Raphson technique. Each linear system is solved using the preconditioned conjugate gradient. The new preconditioner is based on projections onto a subspace associated with the bulk modes of deformation. The condition number of the preconditioned stiffness matrix and consequently the rate of convergence of the preconditioned conjugate gradient are totally insensitive to increasing bulk modulus. The method has been applied to model problems in linear and nonlinear 2D and 3D using a near-incompressible hyperelastic material model. The performance of the iterative method compares favorable with direct solvers as well as with conjugate gradient methods for indefinite systems, in terms of storage requirements, operation count and CPU time.
The Worldwide Availability of Gold

This paper summarizes Bureau of Mines research relating to the state of the world gold industry. The authors discuss the world gold industry structure, demonstrated gold resources, current production, and the long-term cost and availability of potential future gold production. The long-term cost and availability of primary gold production from 111 significant producing mines and developing deposits in 13 market economy countries (MECs) is evaluated. Total recoverable gold available (as of January 1984) from the evaluated mines and deposits is estimated at 819 million troy ounces. The Republic of South Africa is estimated to account for 87% of total recoverable gold. The USA and Canada account for 4% and 4.5% of the total, respectively. Eighty-three per cent of total recoverable gold is available at a constant 1984 break-even price of $400 per ounce, and 70% is available at $300 per ounce. South Africa accounts for 90% of the gold available at $400 per ounce or less. Gold resources in the Soviet Union and China are discussed but not evaluated for costs of production. Some conclusions of the analyses are that South Africa should remain the largest world producer until the year 2000 and annual MEC output in the year 2000 should not be significantly different from current output, given constant 1984 gold prices of more than $300 per ounce.
Modality, Normativity, and Intentionality*

A striking feature of the contemporary philosophical scene is the flourishing of a number of research programs aimed in one way or another at (as Dretske puts it) making intentional soup out of nonintentional bones-more carefully, specifying in a resolutely nonintentional, nonsemantic vocabulary, sufficient conditions for states of an organism or other system to qualify as contentful representations. This is a movement with a number of players, but for my purposes here, the work of Dretske, Fodor, and Millikan can serve as paradigms. The enterprise in which they are jointly engaged is not so much one of conceptual analysis as it has been traditionally understood as one of conceptual engineering. That is, instead of thinking about what ordinary people or even sophisticated philosophers already mean by terms such as 'representation', they appeal to the tools of the special sciences (for instance, information theory and evolutionary biology) to describe abstractly, but in criticizable detail, how one might craft a situation in which some state arguably deserves to be characterized as 'representationally contentful' in various important senses. Insofar as the theories are good ones, they may shed light on how human knowers actually work. But their immediate aim is a broader one: to say what would count as doing the trick, rather than how we manage to do it. It is not hard to get into a position from which intentionality1 can seem philosophically puzzling. One need not, for instance, be an atoms-in-the-void physicalist in order to want to understand better the nature of the transition from a world devoid of semantic properties to one in which they are at least locally rife. One way of dispelling the sense of mystery that threatens to surround such a transition (indeed, where such a story is possible, the very
“Community Power and the Retreat from Politics; Full Circle After Twenty Years?”

This paper traces the development of research on community politics since the classic study of Atlanta by Floyd Hunter in 1953. It is claimed that Hunter's contributions were largely misunderstood because of the theoretical and methodological climate of the 1950'S and that a reappraisal of that work shows it to be more sensitive to real political issues than much of the research that has been conducted in the intervening twenty years. An evaluation of where the field went wrong may help inform contemporary work on political economy.
Spatial Dynamics and Heterogeneity in the Cyclicality of Real Wages

Neither the issue of how local and aggregate labor markets interact over time-nor the issue of how heterogeneity by education, race, and other factors interacts with these spatial dynamics-has prev...
Telomere length and risk of glioma

Background Telomere length in blood or buccal cell DNA has been associated with risk of various cancers. Glioma can be a highly malignant brain tumor and has few known risk factors. Genetic variants in or near RTEL1 and TERT, key components of telomere biology, are associated with glioma risk. Therefore, we evaluated the association between relative telomere length (RTL) and glioma in a prospective study.
Social Competence Intervention for Elementary Students with Aspergers Syndrome and High Functioning Autism

Despite frequent reports of academic success, individuals with high functioning autism or Aspergers Syndrome (HFA/AS) often manifest deficits in social abilities. These deficits can lead to daily difficulties, and negative long-term outcomes. Deficits in social competency are evident in this population from an early age, as children with HFA/AS present unique challenges relating to peers, interpreting complex contextual cues, and transitioning across settings. A paucity of social interventions exist that target elementary-age children with HFA/AS and their combination of core social competence deficit areas: theory of mind (ToM), emotional recognition, and executive functioning. The current study expanded on the Social Competence Intervention (for adolescents; SCI-A), as detailed in Stichter et al. (J Autism Dev Disorders 40:1067-1079, 2010), by adjusting the curriculum to meet the needs of an elementary population. Results indicate significant improvements on direct assessments measuring theory of mind and problem solving, and parent perceptions of overall social abilities and executive functioning for 20 students, aged 6-10, with HFA/AS. The elementary SCI program appears promising, however, additional replications are necessary including expansion to school settings.
Synthesis of fluorescent nucleoside analogs as probes for 2′-deoxyribonucleoside kinases

Abstract We are reporting on the synthesis of fluorescent nucleoside analogs with modified sugar moieties (e.g., sugars other than ribose and 2′-deoxyribose). Four novel derivatives of the fluorescent thymidine analog 6-methyl-3-(β-D-2′-deoxyribofuranosyl) furano-[2,3-d]pyrimidin-2-one were synthesized via Sonogashira reaction and subsequent copper-catalyzed cycloaddition. These compounds represent promising tools for studying nucleoside metabolism inside living cells, as well as for screening directed evolution libraries of 2′-deoxyribonucleoside kinases with new and improved activity for the corresponding nucleoside analogs.
A perfusion phantom for quantitative medical imaging

A perfusion phantom with unique features and a wide variety of applications in MR and other imaging modalities is presented. The phantom is especially suited for tissue perfusion simulation with diffusible and non-diffusible MR tracers. A network of micro-channels in the scale of actual capillaries replicates the blood flow in tissues. Using microfabrication techniques, networks with any desired pattern can be generated. Since the geometry of networks is known, flow rate, delay, dispersion and other fluid parameters can be exactly calculated using finite elements numerical methods. These calculated results can be used to investigate the accuracy of experimental measurements and the precision of mathematical models.
Segregation in irradiated titanium alloys

Abstract Radiation-induced segregation of V, Al and Mo in α-phase titanium alloys was investigated. Ion irradiation (2.1-MeV Ar + ) at 650°C was used to simulate elevated-temperature neutron irradiation effects. Solute segregation in the near-surface regions of irradiated Ti-6Al-4V, Ti-8Al-1V-1Mo, Ti-3V and Ti-8.7Al was measured with an Auger depth profiling technique. The depth profiles showed evidence of radiation-induced V, Mo and Al segregation toward sample surfaces. This is in accord with a solute size effect.
Receptors for thyrotropin-releasing hormone (TRH) in rabbit spinal cord

Abstract Specific binding of3H-labeled[3-Me-His2]TRH([3H]MeTRH) to membranes of rabbit spinal cord (thoracic) involved a homogeneous population of high-affinity sites (Kd = 2.7 ± 0.17 (n= 5)nM, Bmax= 204 – 12(5)fmol/mg protein). TRH analogs competed for the binding in the following rank order of potency: MeTRH>TRH>TRH-Gly-NH2 >Ser-His-Pro-NH2 >Thr-His-Pro-NH2 > pGlu-His-Pro-NH-C2H5>TRH-free acid. Competition experiments with rat amygdala, run in parallel with rabbit spinal cord, revealed a closely similar pattern of activity. These properties help identify binding sites in the rabbit spinal cord as physiological receptors for TRH. The binding sites resemble receptors previously demonstrated in pituitary and CNS tissues of other species. The densities of [3H]MeTRH binding sites in different segments were generally similar, although density in the thoracic segment appeared to be somewhat higher. In all segments, binding seemed to be enriched in the dorsal gray matter. Dorsal roots and their associated ganglia, however, displayed little or no binding.
Listeria monocytogenes in Multiple Habitats and Host Populations: Review of Available Data for Mathematical Modeling

Listeria monocytogenes has the ability to survive and multiply in diverse habitats and to cause infection in a variety of animal species and humans. We evaluated the literature on survival and multiplication within and transmission among multiple host populations and habitats, including man, sewage, general environment (soil, water, and vegetation), silage (fermented plant material), animals (including wild and domestic animals), and food processing plants. The available knowledge on L. monocytogenes transmission dynamics was translated into the key process nodes of interrelated host- and habitat-specific mathematical models, providing a starting framework for future modeling work and the ultimate development of a system-wide model for evaluation of its transmission, and strategies to reduce human exposure. Because of the ability of L. monocytogenes to survive and multiply in many habitats and hosts, and the number of possible transmission routes, it is highly unlikely that it could be eradicated from any habitat or host, including man. However, L. monocytogenes load within and transmission among habitats and host populations could probably be reduced. Based on the published information, we hypothesize that three recent anthropogenic practices increase the load within and transmission among reviewed habitats and host populations: extended refrigerated storage of ready-to-eat foods allowing L. monocytogenes growth in foods that are contaminated during production or subsequent handling; feeding domestic ruminants with silage often contaminated with L. monocytogenes; and dispersal of contaminated products of sewage treatment to agricultural fields and waters. Future mathematical modeling work could test how much the reduction of L. monocytogenes load and transmission in hosts and habitats associated with these anthropogenic practices would reduce human exposure and consequently human listeriosis.
SU‐GG‐T‐13: Fast Seed Localization On MR Images For Post‐Prostate Implant Dosimetry

Purpose: Accurate and reliable post‐prostate implant dosimetric analysis requires optimal identification of the seeds on CT and optimal description of soft tissues on MRI. We present a fast seed localization technique for MRI that is also robust from motion and other artifacts. The robustness of this technique was further investigated with clinical cases. Method and Materials:CT and 1.5T MR axial images of 4 patients were acquired four weeks post‐implant were studied. Seed localization was first performed on CTimages using either automatic seed detection or manual identification process. Several seeds in CT and seed voids in MR as well as anatomical landmarks were selected as control points. A thin‐plate‐spline deformable model was then constructed to map all the seeds from the CT to the MR. The robustness of this technique was further investigated by simulating various control point sets. The test started with the entire identifiable seed collections on both CT and MR images. The seeds forming the convex hull and 2 anatomical landmarks were then used as the control point set for TPS modeling. All seed positions were mapped from CT to MR following the TPS model. Seed position accuracy was examined. The process is repeated by continuously eliminating the control points to the last 3. Results and Discussion: The seeds localized on CTimages were successfully mapped to the MRIimages with only about 8 control points. The mapping can be accomplished in less than 5 minutes. Most of the mis‐alignments were with peripheral seed positions. The slice thickness also contributed to the inaccuracy in SI direction as some of the seed positions were rounded to the closest slice. Increase the number of anatomical landmarks may further improve the accuracy. Conclusion: The fast mapping of seed locations from CT to MR facilitates a reliable post‐implant dosimetric analysis.
Pressure at Residual Volume: A Useful Adjunct to Standard Fill Cystometry

AbstractPurpose: Determining the role of the bladder in incontinence and/or upper urinary tract deterioration involves the cystometrographic evaluation of detrusor compliance. Management decisions based on information provided by standard fill water cystometry assume that data reflect the physiological state of the patient but this is not always true. We report the use of pressure at residual volume as a physiological measurement to aid in the interpretation of data obtained during standard fill urodynamics.Materials and Methods: All patients presenting to our urodynamic suite for standard cystometry between June 1994 and December 1995 underwent measurement of bladder pressure at insertion of the urodynamic catheter. Residual volume and pressure measured before draining this urine, that is pressure at residual volume, were recorded. The bladder was then filled at a rate equal to or less than 10% per minute of known or predicted capacity. When a volume equal to the residual volume had been instilled, filli...
The oxidation of aldehydes to acids with calcium hypochlorite [Ca(OCl)2]

Abstract Calcium hypochlorite is an efficient reagent for the oxidation of aldehydes to the corresponding acids. Reactions are carried out at ambient temperature in aqueous acetonitrile-acetic acid solution. Aliphatic aldehydes and aromatic aldehydes with electron withdrawing groups afford good to excellent yields. Nuclear chlorination is the preferred reaction in aromatic aldehydes with electron donating groups.
Sustained-release theophylline pharmacokinetics in the cat

Theophylline was administered in a three-way crossover design study to six cats intravenously (Aminophylline USP, Invenex Laboratories, Chagrin Falls, OH) and orally as two sustained-release formulations (Slo-bid Gyrocaps (SB), William H. Rorer, Inc., Fort Washington, PA; Theo-Dur Tablets (TD), Key Pharmaceuticals, Miami, FL). Values were determined for mean residence time (SB = 19.4 +/- 3.2 h; TD = 15.8 +/- 4.8 h), mean absorption time (SB = 8.0 +/- 2.3 h; TD = 4.8 +/- 2.3 h), absolute bioavailability (SB = 82 +/- 27%; TD = 76 +/- 38%), and time to peak plasma concentrations (SB = 8 h; TD = 8 h). After normalization to a dose of 25 mg/kg, the average peak plasma concentrations were also predicted (SB = 10.5 +/- 3.4 micrograms/ml; TD = 14.3 +/- 6.7 micrograms/ml). Slo-bid was predicted to provide the least peak:trough fluctuation in theophylline concentrations. Slo-bid and Theo-Dur appear to have pharmacokinetic characteristics which, if given once-daily, would maintain plasma theophylline concentrations of 5-20 micrograms/ml in the cat.
The Record of Congress in Committee Staffing.

One of the salient reforms of Congress embodied in the Legislative Reorganization Act of 1946 was the authorization granted standing committees for the employment of adequate staff assistance. The point had been made repeatedly by critics within and outside the Congress that its standing committees must be equipped with first-rate professional staffs if they are to make intelligent legislative decisions on the increasingly complex and technical problems presented to the legislators for solution. Reliance upon executive branch research studies or upon the detail of executive agency technicians to the committees was held by many to be fraught with the danger of injecting special pleading and biases for the increasing number of administration-sponsored bills. For Congress to function as a coequal partner with the executive in the legislative process, these critics deemed it essential that Congress empower itself to obtain its own independent staff services and that it pay adequately for them.
F-RISC/I: fast reduced instruction set computer with GaAs (H) MESFET implementation

F-RISC/I is a monolithic GaAs microprocessor with a seven stage pipeline implemented with SBFL standard cells. It is targeted at a clock rate of 400 MHz with a CPI of 1.45. The impacts of GaAs technology on system architecture, CPU architecture, circuit level optimization, implementation, performance, and testing of F-RISC/I are discussed. The GaAs technology environment is investigated and compared to that of Si. >
Archaeology of Atlantic Africa and the African Diaspora

Archaeology of Atlantic Africa and the African Diaspora, edited by Akinwumi Ogundiran and Toyin Falola, Bloomington and Indianapolis, Indiana University Press, 2007, 509pp., $59.95, ISBN 978-0-253-...
X-ray absorption and electron paramagnetic resonance studies of Cu(II) sorbed to silica : Surface-induced precipitation at low surface coverages

Both EPR and XAFS spectroscopy were used to characterize the sorption of Cu(II) on silica surfaces at extremely low surface coverage (0.8 and 9.9% monolayer). The binding structure of Cu(II) on silica surfaces revealed by XAFS experiment was compared to that predicted by EPR spectra. Our XAFS results show that Cu(II) hydroxide clusters form on silica surfaces even at surface coverage as low as 0.8% of a monolayer. However, we observed low EPR intensity and line-broadening which has been assigned to dipole-dipole interactions between isolated Cu(II) ions. The results of our XAFS studies indicate that the loss of EPR intensity and line-broadening can be traced to Cu(OH)2 clusters on silica surfaces.
Influence of environment on the fatigue of Pb-Sn solder joints

The effect of a vacuum ( approximately 10/sup -6/ torr) on the low-cycle fatigue life (25%, 50%, 75%, and 95% drop in load) of 10Sn90Pb and 63Sn37Pb solder joints tested in shear was investigated in total strain control (by Delta gamma /sub t/=0.006 to 0.5, nu =0.1 Hz ramp cycling) at 300 K. The influence of a grease coating was also determined for the 63Sn37Pb alloy for Delta gamma /sub t/=0.07 to 0.8. No clear effect of vacuum occurred for the strain range considered. However, the grease coating improved fatigue life. Possible explanations for the observed effects are given, including chemical reaction with the specimen surface, i.e. a Rhebinder effect; a crack-filling effect leading to a decrease in the stress intensity factor; and a reduction in friction along the sliding crack surfaces giving less debris and thereby a lower tensile stress at the crack tip. >
Is inhibition of cyclooxygenase required for the chemopreventive effect of NSAIDs in colon cancer? A model reconciling the current contradiction.

NSAIDs are powerful chemopreventive agents for colon cancer, but their mechanism of action remains unknown. Their best recognized pharmacological property is inhibition of the enzyme cyclooxygenase (COX), which catalyzes the synthesis of prostaglandins; however, additional effects are well documented. Current studies on the mechanism of the chemopreventive effect of NSAIDs lead to two contradictory conclusions: NSAIDs prevent colon cancer either by inhibiting the activity of COX, or through mechanisms that do not require COX inhibition. To resolve this apparent conflict, after examining several alternatives, we propose a model, which assumes that both mechanisms are correct but that they exert their effect either on different steps of the multistep process of colon carcinogenesis or on different control mechanisms. This postulated dual action of NSAIDs may explain their remarkable effectiveness in colon cancer prevention. Unraveling these mechanistic details can be very rewarding for the design of more refined approaches to cancer chemoprevention and for a deeper understanding of colorectal carcinogenesis.
Topoisomerase I-Dependent Viability Loss in Saccharomyces cerevisiae Mutants Defective in Both SUMO Conjugation and DNA Repair

Siz1 and Siz2/Nfi1 are the two Siz/PIAS SUMO E3 ligases in Saccharomyces cerevisiae. Here we show that siz1Delta siz2Delta mutants fail to grow in the absence of the homologous recombination pathway or the Fen1 ortholog RAD27. Remarkably, the growth defects of mutants such as siz1Delta siz2Delta rad52Delta are suppressed by mutations in TOP1, suggesting that these growth defects are caused by topoisomerase I activity. Other mutants that affect SUMO conjugation, including a ulp1 mutant and the nuclear pore mutants nup60Delta and nup133Delta, show similar top1-suppressible synthetic defects with DNA repair mutants, suggesting that these phenotypes also result from reduced SUMO conjugation. siz1Delta siz2Delta mutants also display TOP1-independent genome instability phenotypes, including increased mitotic recombination and elongated telomeres. We also show that SUMO conjugation, TOP1, and RAD27 have overlapping roles in telomere maintenance. Top1 is sumoylated, but Top1 does not appear to be the SUMO substrate involved in the synthetic growth defects. However, sumoylation of certain substrates, including Top1 itself and Tri1 (YMR233W), is enhanced in the absence of Top1 activity. Sumoylation is also required for growth of top1Delta cells. These results suggest that the SUMO pathway has a complex effect on genome stability that involves several mechanistically distinct processes.
Accumulation of the transcription factor ABA-insensitive (ABI)4 is tightly regulated post-transcriptionally

ABA-INSENSITIVE (ABI)4 is a transcription factor implicated in response to ABA in maturing seeds, and seedling responses to ABA, salt, and sugar. Previous studies have shown that ABI4 transcripts are high in seeds and in seedlings exposed to high concentrations of glucose and, to a lesser extent, osmotic agents and ABA, but that transcript levels are very low through most of vegetative growth. This study examined ABI4 protein accumulation indirectly, using transgenic lines expressing fusions to GFP and GUS. The GFP fusions were active, but undetectable visually or immunologically. Comparison of transcript and activity levels for GUS expression showed that inclusion of the ABI4 coding sequence reduced the ratio of activity to transcript ∼40-fold when driven by the CaMV 35S promoter, and nearly 150-fold when controlled by the ABI4 promoter. At least part of this discrepancy is due to proteasomal degradation of ABI4, resulting in a half-life of 5-6 h for the ABI4-GUS fusion. Comparison of the spatial localization of transcripts and fusion proteins indicated that the protein preferentially accumulated in roots such that transcript and protein distribution had little similarity. The components mediating targeting to the proteasome or other mechanisms of spatial restriction have not yet been identified, but several domains of ABI4 appear to contribute to its instability.
Elliptical quantum dots as on-demand single photons sources with deterministic polarization states

In quantum information, control of the single photon's polarization is essential. Here, we demonstrate single photon generation in a pre-programmed and deterministic polarization state, on a chip-scale platform, utilizing site-controlled elliptical quantum dots (QDs) synthesized by a top-down approach. The polarization from the QD emission is found to be linear with a high degree of linear polarization and parallel to the long axis of the ellipse. Single photon emission with orthogonal polarizations is achieved, and the dependence of the degree of linear polarization on the QD geometry is analyzed.
The Not-so-Random Drunkard's Walk

This dataset contains the results of a quasi-experiment, testing Karl Pearson's “drunkard's walk” analogy for an abstract random walk. Inspired by the alternate hypothesis that drunkards stumble to...
Flexible Chemical Sensors

Publisher Summary This chapter describes the flexible chemical sensors. Traditional chemical sensors based on conductive polymers over polymer substrates are generally flexible. However, with the advent of high-quality nanowires and nanotubes, and the rapid development of flexible electronics, which involves many breakthroughs in the synthesis, and manipulation of these nanoscale materials, significant progress has been made in modern flexible chemical sensors. In traditional conductive polymer chemical sensors, self-organization in many solution-processed, semiconducting conjugated polymers results in complex microstructures, in which ordered microcrystalline domains are embedded in an amorphous matrix. The goals for a flexible chemical sensor are portability, high sensitivity, low false alarm rate, and fast response. After initial positive identification, detailed analysis can be carried out in a laboratory environment. At present, there are a few niche areas that demand flexible chemical sensors for compact electronic device design; for example, leak inspection for underground piping, flammable and/or toxic gas detection in waste storage areas and confined spaces, security checkpoints for improvised explosive devices, sensing functions in wearable smart garments, and sensing and health monitoring in biomedical devices and tools.
DRASIC Contributes to pH-Gated Currents in Large Dorsal Root Ganglion Sensory Neurons by Forming Heteromultimeric Channels

For many years it has been observed that extracellular acid activates transient cation currents in large-diameter mechanosensory dorsal root ganglion (DRG) neurons. However, the molecular basis of ...
From striving to thriving: systems thinking, strategy, and the performance of safety net hospitals.

BACKGROUND Safety net hospitals (SNH) have, on average, experienced declining financial margins and faced an elevated risk of closure over the past decade. Despite these challenges, not all SNHs are weakening and some are prospering. These higher-performing SNHs provide substantial care to safety net populations and produce sustainable financial returns. PURPOSE Drawing on the alternative structural positioning and resource-based views, we explore strategic management as a source of performance differences across SNHs. METHODOLOGY/APPROACH We employ a mixed-method design, blending quantitative and qualitative data and analysis. We measure financial performance using hospital operating margin and quantitatively evaluate its relationship with a limited set of well-defined structural positions. We further evaluate these structures and also explore the internal resources of SNHs based on nine in-depth case studies developed from site visits and extensive interviews. FINDINGS Quantitative results suggest that structural positions alone are not related to performance. Comparative case studies suggest that higher-performing SNH differ in four respects: (1) coordinating patient flow across the care continuum, (2) engaging in partnerships with other providers, (3) managing scope of services, and (4) investing in human capital. On the basis of these findings, we propose a model of strategic action related to systems thinking--the ability to see wholes and interrelationships rather than individual parts alone. PRACTICE IMPLICATIONS Our exploratory findings suggest the need to move beyond generic strategies alone and acknowledge the importance of underlying managerial capabilities. Specifically, our findings suggest that effective strategy is a function of both the internal resources (e.g., managers' systems-thinking capability) and structural positions (e.g., partnerships) of organizations. From this perspective, framing resources and positioning as distinct alternatives misses the nuances of how strategic advantage is actually achieved.
Nondestructive DNA Extraction Techniques for Soybean (Glycine Max) Seeds

ABSTRACTWhile maintaining high germination rates, genotyping single seeds are useful in breeding and genetics. Nondestructive single-seed genomic DNA extraction protocols using 12 mg cotyledon tissue with a modified cetyl trimethyl ammonium bromide (CTAB) technique and a commercial seed DNA extraction kit using 1 mg cotyledon tissue were developed for dry soybean seeds and cross-verified with leaf DNA analysis. The DNA extracted by these methods was sufficient for polymerase chain reaction (PCR), and the results were reproducible for several endogenous genes and transgenes in D-myo-inositol 3-phosphate synthase (MIPS) mutant seeds (GM-lpa-TW1). This single-seed DNA-analysis method is amenable to rapid high-throughput genotype screening and verifying the genetic purity of seed stocks.
Will there be a shortage of dental auxiliaries in the future

The number of graduates from dental hygiene programs continues to increase, but retention of dental hygienists in practices is a concern. The numbers of graduates from dental assisting and especially dental laboratory technology programs are decreasing. The impact on dental practice size and practice productivity is considered.
Operative ultrasonography for lung cancer surgery.

During 60 operations for lung cancer, high-resolution (7.5 MHz) operative ultrasonography was performed to evaluate direct cardiovascular invasion of tumor (24 operations), lymph node metastasis (30 operations), and liver metastasis (13 operations). Immediately after thoracotomy or sternotomy but before tissue dissection, operative scanning enabled delineation and evaluation of the vessels and heart (atrium) behind or within the tumor and detection of regional lymph nodes. The accuracy of operative ultrasound in diagnosing the presence or the extent of cardiovascular invasion was 91.7% (22 of 24 operations), which was significantly (p
Approach to Foreign Body Ingestion, Food Impaction, and Caustic Injury

Foreign body ingestion and food impaction are conditions that may require prompt endoscopic therapy. Although the majority of ingested foreign bodies will eventually pass through the gastrointestinal tract, early intervention is necessary in some cases to prevent complications and alleviate symptoms. Although complications from ingested foreign bodies and impacted food boluses are rare, they can be severe, including aspiration, perforation, obstruction, and fistula and stricture formation. In addition, caustic injury from ingestion of acid or alkali is a cause of significant morbidity and mortality, especially in children. Early recognition, timely endoscopic evaluation of the degree of injury, and prevention of life-threatening complications are critical in triaging patients for either supportive or more invasive surgical intervention. Herein, the prevalence, predisposing factors, clinical presentation, and initial management of these gastrointestinal emergencies are highlighted. Specific endoscopic tools and techniques in managing ingested foreign bodies and food impaction are reviewed in a separate chapter. Suggested algorithms for the management of foreign body ingestion and food impaction are outlined.
A comparison of radiometric calibration techniques for lunar impact flashes

Abstract Video observations of lunar impact flashes have been made by a number of researchers since the late 1990's and the problem of determination of the impact energies has been approached in different ways Bellot Rubio et al. (2000a, b), Yanagisawa et al. (2008), Bouley et al. (2012), Suggs et al. (2014), Rembold and Ryan (2015), Ortiz et al. (2015), Madiedo et al. (2015). The wide spectral response of the unfiltered video cameras in use for all published measurements necessitates color correction for the standard filter magnitudes available for the comparison stars but this is not typically considered. In our approach, the published color of the comparison star and an estimate of the color of the impact flash is used to correct it to the chosen filter bandpass. Magnitudes corrected to standard filters are then used to determine the luminous energy in the filter bandpass according to the stellar atmosphere calibrations of Bessell et al. (1998). In this paper we compare the various photometric calibration techniques and calculation of luminous energy (radiometry) of impact flashes. This issue has significant implications for determination of luminous efficiency, predictions of impact crater sizes for observed flashes, and the determination of the flux of meteoroids in the 10 s of grams to kilograms mass range.
Composition of elastin like polypeptide-collagen composite scaffold influences in vitro osteogenic activity of human adipose derived stem cells.

Abstract Objective Collagen-based scaffolds for guided bone regeneration (GBR) are continuously improved to overcome the mechanical weaknesses of collagen. We have previously demonstrated superior mechanical characteristics of the elastin-like polypeptide (ELP) reinforced collagen composites. The objectives of this research were to evaluate the efficacy of ELP-collagen composites to culture human adipose-derived stem cells (hASCs) and allow them to undergo osteogenic differentiation. We hypothesized that hASCs would show a superior osteogenic differentiation in stiffer ELP-collagen composites compared to the neat collagen hydrogels. Methods Composite specimens were made by varying ELP (0–18 mg/mL) and collagen (2–6 mg/mL) in a 3:1 ratio. Tensile strength, elastic modulus, and toughness were determined by uniaxial tensile testing. hASCs cultured within the composites were characterized by biochemical assays to measure cell viability, protein content, and osteogenic differentiation (alkaline phosphatase activity, osteocalcin, and Alizarin red staining). Scanning electron microscopy and energy dispersive spectroscopy were used for morphological characterization of composites. Results All composites were suitable for hASCs culture with viable cells over the 22-day culture period. The ELP-collagen composite with 18 mg/mL of ELP and 6 mg/mL of collagen had greater tensile strength and elastic modulus combined with higher osteogenic activity in terms of differentiation and subsequent mineralization over a period of 3 weeks compared to other compositions. The extra-cellular matrix deposits composed of calcium and phosphorous were specifically seen in the 18:6 mg/mL ELP-collagen composite. Significance The success of the 18:6 mg/mL ELP-collagen composite to achieve long-term, 3-dimensional culture and osteogenic differentiation indicates its potential as a GBR scaffold.
HIV-1 Capsid Function Is Regulated by Dynamics: Quantitative Atomic-Resolution Insights by Integrating Magic-Angle-Spinning NMR, QM/MM, and MD.

HIV-1 CA capsid protein possesses intrinsic conformational flexibility, which is essential for its assembly into conical capsids and interactions with host factors. CA is dynamic in the assembled capsid, and residues in functionally important regions of the protein undergo motions spanning many decades of time scales. Chemical shift anisotropy (CSA) tensors, recorded in magic-angle-spinning NMR experiments, provide direct residue-specific probes of motions on nano- to microsecond time scales. We combined NMR, MD, and density-functional-theory calculations, to gain quantitative understanding of internal backbone dynamics in CA assemblies, and we found that the dynamically averaged 15N CSA tensors calculated by this joined protocol are in remarkable agreement with experiment. Thus, quantitative atomic-level understanding of the relationships between CSA tensors, local backbone structure, and motions in CA assemblies is achieved, demonstrating the power of integrating NMR experimental data and theory for cha...
Mechanical circulatory support for the failing functional single ventricle

The advent of surgical palliation for functional single ventricle (FSV) heart defects was an impressive feat for pediatric cardiovascular surgery and medicine just a few decades ago. Parents were given hope for what would have been uniformly fatal congenital heart disease, and today, substantial survival is expected by both families and care providers for neonates with many types of FSV defects. However, decades have since past and these very same patients who were successfully palliated are now facing despair themselves as they encounter significant cardiovascular issues. These issues can be classified as Fontan failure (as evidenced by protein losing enteropathy and plastic bronchitis) and contractile failure (systolic or diastolic) of their single ventricle.
Human infection with Entamoeba polecki.

A case of infection due to Entamoeba polecki in a Peace Corps volunteer is presented. Although the patient was intensively treated for E. histolytica infection for more than a year, no serologic or pathologic confirmation of this diagnosis could be elicited and her clinical condition did not improve significantly. The significance of finding E. polecki in humans is discussed and the tests necessary for detection and the criteria for identification are reviewed.