cssi/SciSciGPT-SciSciNet huggingface dataset:
A Min–Max Property of Chordal Bipartite Graphs with Applications

We show that if G is a bipartite graph with no induced cycles on exactly 6 vertices, then the minimum number of chain subgraphs of G needed to cover E(G) equals the chromatic number of the complement of the square of line graph of G. Using this, we establish that for a chordal bipartite graph G, the minimum number of chain subgraphs of G needed to cover E(G) equals the size of a largest induced matching in G, and also that a minimum chain subgraph cover can be computed in polynomial time. The problems of computing a minimum chain cover and a largest induced matching are NP-hard for general bipartite graphs. Finally, we show that our results can be used to efficiently compute a minimum chain subgraph cover when the input is an interval bigraph.
The role of mental computations in judgments of area and volume

Area and volume judgments are usually underestimates of true size. The possibility that these underestimations are more dependent on cognitive factors than on sensory ones was investigated in two experiments. In Experiment 1, subjects judged the products of multiplication problems varying in number of multiplications and number of digits per number. Judgments were analyzed using power functions. The power function exponents for problems requiring one multiplication and two multiplications were very similar to previously obtained exponents for judgments of area and volume, respectively. In Experiment 2, subjects judged three-number multiplication problems and volume ratios of depicted, rectangular boxes. Power-function exponents for these two kinds of tasks had similar means and standard deviations and were significantly correlated. These results support the hypothesis that underestimations of area and volume judgments are due primarily to errors in mental multiplication.
The 7 habits of highly effective psychopharmacologists, part 3: sharpen the saw with selective choices of continuing medical education programs.

Issue: Highly effective practitioners of psychopharmacology recognize that they must continually sharpen their saw as they cut through the diagnosing and prescribing decisions of daily practice. Choosing the right continuing medical education programs is critical to attaining balanced self-renewal in this era of rapidly expanding knowledge about neuroscience and new therapeutic options.
Fast neutrons in the earth's atmosphere. 1. variation with depth

A series of balloon flights at lambda = 41 deg N to atmospheric depths of about 3.6 g/cm/sup 2/ were conducted in 1963. A phoswich type of scintillation counter, which has a high efficiency for neutrons in the 1- to 14- Mev range, was employed. Gamma rays and charged particles are distinguished through pulse-shape discrimination and are separately telemetered. the experiments revealed that the mean free path for absorption in the lower atmosphere was 169 plus or minus 13 g/cm/sup 2/, and that the neutron flux at the 90g/cm/sup 2/ transition maximum was 1.1 neutrons/cm/sup 2/ sec. The flux at the highest altitudes attained was 0.39 n/cm/sup 2/ sec, and an extrapolation to the top of the atmosphere that follows Newkirk's theory yields 0.24 plus or minus 0.02 n/cm/sup 2/ sec for the neutron flux at the boundary. the absolute values are accurite to plus or minus 20 per cent. The flux as a function of depth is in good agreement with the calculations of Newkirk and of Lingenfelter. It is in disagreement with the original calculations of Hess, Canfield, and Lingenfelter. The extrapolated flux is lower than the fluxes measured by others in satellite experiments. The experimental discrepancy maymore » be caused by local production effects in the satellites. A featureless differential energy spectrum with an E/sup -1.3 plus or minus .1/ dependence was measured. (auth)« less
Heat of hydrogenation of 1,5-dehydroquadricyclane. A computational and experimental study of a highly pyramidalized alkene

The radical anion of the highly pyramidalized alkene 1,5-dehydroquadricyclane (1) was generated in the gas phase from the Squires reaction of 1,5-bis(trimethylsilyl)quadricyclane with F-/F2. The electron binding energy and proton affinity of 1*- were determined by bracketing experiments to be 0.6 +/- 0.1 eV and 386 +/- 5 kcal/mol, respectively. These values are in good agreement with values predicted by density functional theory (B3LYP/6-31+G*) and ab initio (CASPT2/6-31+G*) calculations. The experimental heat of hydrogenation of 1, obtained from a thermochemical cycle, was found to be 91 +/- 9 kcal/mol. This value of deltaH(H2) leads to values of 67 +/- 9 kcal/mol for the olefin strain energy (OSE) of 1, 172 +/- 9 kcal/mol for its heat of formation, and 23 +/- 9 kcal/mol for its pi bond dissociation enthalpy. Since the retro-Diels-Alder reaction of neutral 1 is computed to be highly exothermic, the finding that 1*- apparently does not undergo a retro-Diels-Alder reaction is of particular interest. The B3LYP/6-31+G* optimized geometry of 1 suggests that the bonding in this alkene is partially delocalized, presumably because the highly pyramidalized double bond in 1 interacts with the distal cyclopropane bonds in a manner that eventually leads to a retro-Diels-Alder reaction. The good agreement of the B3LYP and (2/2)CASPT2 values for the heat of hydrogenation and OSE of 1 with the experimentally derived values provides indirect evidence for the correctness of the B3LYP prediction that the equilibrium geometry of 1 lies part way along the reaction coordinate to the transition structure for the retro-Diels-Alder reaction.
Résistance aux antibiotiques des Staphylococcus aureus, Escherichia coli et Salmonella isolés des aliments

Resume L'etude de la sensibilite aux antibiotiques, sulfamides et furanes de 873 souches bacteriennes, comprenant 587 Escherichia coli , 21 Salmonella et 265 Staphylococcus aureus isoles de divers produits alimentaires dans l'Est de la France en 1974–1975, a montre que 24,5 % d'entre elles presentaient une resistance simple ou multiple aux antibiotiques. Les Staphylocoques dores sont frequemment resistants aux sulfamides et a un moindre degre, aux tetracyclines, les souches resistantes etant principalement rencontrees dans les plats cuisines, les hors-d'œuvres et les pâtisseries. Le pourcentage des E. coli resistants n'atteint que la valeur moderec de 11 %, les produits carnes, notamment ceux a base de volaille, etant les principaux vecteurs de souches resistantes. Chez ceux-ci, les resistances les plus frequentes concernent dans l'ordre les tetracyclines, la nitrofurantoine, la streptomycine et les sulfamides. Les resistances multiples sont courantes, en particulier chez les souches isolees dans les glaces et les viandes. Parmi les 21 souches de Salmonella , se repartissant en 13 serotypes, 3 souches se sont montrees resistantes dont une S. saint-paul multiresistante S C T Su Fu. Le transfert de la resistance aux tetracyclines a E. coli K 12 a pu etre realise in vitro a partir de 2 souches d' E. coli et de la S. saint-paul multiresistante. La oure au bromure d'ethidium n'a pu etre obtenue nettement que chez 2 souches d' E. coli dont la resistance n'etait pas transferable, et chez la S. saint-paul . Aucune resistance a la gentamicine, ni a la tobramycine n'a ete rencontree, et une seule souche d' E. coli s'est montree resistante a la minocycline.
Reactive Oxygen Species-independent Oxidation of Thioredoxin in Hypoxia INACTIVATION OF RIBONUCLEOTIDE REDUCTASE AND REDOX-MEDIATED CHECKPOINT CONTROL

We have investigated the role of cellular redox state on the regulation of cell cycle in hypoxia and shown that whereas cells expressing mutant thioredoxin (Trx) or a normal level of Trx undergo increased apoptosis, cells overexpressing Trx are protected against apoptosis. We show that hypoxia activates p53 and Chk1/Chk2 proteins in cells expressing normal or mutant Trx but not in cells overexpressing Trx. We also show that the activity of ribonucleotide reductase decreases in hypoxia in cells expressing redox-inactive Trx. Although hypoxia has been shown to induce reactive oxygen species (ROS) generation in the mitochondria resulting in enhanced p53 expression, our data demonstrate that hypoxia-induced p53 expression and phosphorylation are independent of ROS. Furthermore, hypoxia induces oxidation of Trx, and this oxidation is potentiated in the presence of 6-aminonicotinamide, an inhibitor of glucose-6-phosphate dehydrogenase. Taken together our study shows that Trx redox state is modulated in hypoxia independent of ROS and is a critical determinant of cell cycle regulation.
Biological Routes to Metal Alloy Ferromagnetic Nanostructures

Magnetic nanoparticles have potential applications in high-density memory devices, but their complicated synthesis often requires high temperatures, expensive reagents, and postsynthesis annealing to achieve the desired magnetic properties. Current synthetic methods for magnetic nanoparticles often require post-synthetic modifications, suggesting that the practical application of magnetic nanoparticles will depend on the development of alternative synthetic strategies. We report a biological template to directly grow magnetic nanoparticles of desired material composition and phase under ambient conditions. A phage display methodology was adapted to identify peptide sequences that both specifically bind to the ferromagnetic L10 phase of FePt and control the crystallization of FePt nanoparticles using a modified arrested precipitation technique. TEM, electron diffraction, STEM, and X-ray diffraction all indicate these nanoparticles are composed of an FePt alloy with some degree of chemical ordering, and SQU...
Focused high-risk population screening for carotid arterial stenosis after radiation therapy for head and neck cancer.

Abstract Background Cervical radiation for head and neck cancer has been associated with an increased incidence of carotid arterial stenosis. Modern radiation therapy delivers higher doses with increasing long-term survival. Accordingly, the prevalence of radiation-associated carotid stenosis may be higher than previously reported. Phase I of this prospective study was to establish the prevalence of carotid artery stenosis after high-dose cervical radiation. Methods From a prospectively maintained database, we identified patients who had received cervical high-dose radiotherapy (minimum 5,500 cGy). All patients were screened with bilateral carotid arterial duplex ultrasonography. We defined disease as “normal or mild” if the carotid stenosis was 50%. The relationship between standard demographic risk factors and screening outcomes was then analyzed. Results Screening was performed in 40 patients (mean age 68.2 years, range 26 to 87). Patients received a mean cumulative radiation dose of 6,420 cGy (range 5,500 to 7,680), with a mean duration of 10.2 years since their last radiation treatment. Sixteen patients (40%) had significant carotid artery stenosis. Patients with and without significant stenosis were comparable in terms of age, radiation dose, tobacco use, comorbidities, and postradiation interval (P = not significant). Six patients (15%) had unilateral complete carotid occlusion and 6 patients (15%) had significant bilateral carotid stenosis. Three patients (7.5%) had sustained a previous stroke after radiation therapy. Conclusions The prevalence of carotid arterial disease in patients with prior cervical radiation therapy is clinically significant and warrants aggressive screening as part of routine preradiation and postradiation care. Focused screening of this high-risk population may be cost effective and medically beneficial in terms of risk factor modification and stroke prevention, and will be examined in phase II of this study.
On the interaction of visualization and analysis: the negotiation of a visual representation in expert problem solving

Abstract This study addresses one of the most frequently suggested strategies for solving problems in mathematics: drawing a diagram. Professional mathematicians were asked to solve problems and their use of the strategy of drawing diagrams as they attempted to find solutions to these problems was studied. Because particular attention was paid to the reasoning processes of mathematicians while they were actually developing their proofs, the study’s findings suggest ways in which experienced problem solvers used diagrams to perform specific subtasks of proof development, and how diagrams helped them complete the activities. In particular, the study suggests that mathematicians build the visual representation in steps which are clearly separated by a few moments, during which they attempt to analyze the visual representation with respect to the problem situation. This analysis consists of some well-structured processes which involve four types of actions: inferring additional consequences, elaborating on the new mathematical information, stating a new goal, and monitoring their problem-solving process.
Developmental lead exposure alters the stimulatory properties of cocaine at PND 30 and PND 90 in the rat

The aim of this study was to examine the effects of perinatal lead exposure on locomotor responding following acute and repeated cocaine challenges (sensitization). Adult female rats were gavaged daily with 0, 8, or 16 mg lead acetate for 30 days prior to breeding. This exposure regimen was maintained throughout gestation and lactation (perinatal exposure). On Day 21, male pups were weaned and lead exposure was discontinued for the remainder of the study. Beginning on postnatal day (PND) 30 or PND 90, and continuing for 14 successive days, separate groups of perinatally-exposed animals were presented with challenges of 10 mg/kg cocaine HCl (i.p.), and tested for locomotor responding. Following this testing period, dose-effect profiles were determined, with animals receiving daily injections of 0, 10, 20, and 40 mg/kg cocaine. The results indicated that both at PND 30 and PND 90 lead-exposed animals were less responsive to the initial administration of cocaine, but exhibited a supersensitivity to the stimulatory effects associated with repeated administration of cocaine, i.e., behavioral sensitization to cocaine was augmented by perinatal lead exposure. Analyses of blood lead levels following the completion of testing revealed that lead levels were below detectable limits for all animals (< 1 μg/dl). Collectively, these findings show that developmental lead contamination produces changes in cocaine sensitivity long after exposure has been discontinued and the toxicant has gained clearance from blood.
LifeTech Institute: Leading Change through Transitional Centers.

Through partnerships with four other state agencies, the LifeTech Institute was designed to provide life skills and technical workforce skills to male parolees. The purpose was to alleviate prison overcrowding, reduce recidivism rates, and prepare a trained workforce to supplement the demanding workforce needs of the state's construction industry. Results have been astounding.
Factitious pheochromocytoma: novel mimickry by Valsalva maneuver and clues to diagnosis.

Factitious pheochromocytoma usually occurs in patients surreptitiously ingesting adrenergic medications. We encountered a case of factitious pheochromocytoma wherein the subject mimicked hemodynamic (profound hypertension) and biochemical (plasma catecholamine elevation) manifestations of the illness by consciously altering autonomic function with Valsalva maneuver. Clues to this presentation included visible performance of Valsalva maneuver, marked disparity between blood pressures recorded in the presence and absence of the subject's knowledge, normal urinary catecholamine and metabolite excretion, and normal plasma chromogranin A. We reproduced, in part, the hemodynamic and biochemical manifestations of this presentation with Valsalva maneuver in healthy subjects.
Ultrastructural immunolocalization of actin in a fungus

We have successfully localized fungal actin for the first time using immuno-electron microscopy and hyphal tips of the rice blast pathogenMagnaporthe grisea. Following ultrarapid freezing, samples were processed in a novel substitution fluid of 10% acrolein in anhydrous ethanol and embedded in LR White resin. A monoclonal anti-actin antibody, previously shown to recognizeM. grisea actin, bound specifically to filasomes concentrated in the peripheral cytoplasm of subapical regions, and to the core-region of the Spitzenkorper.
Inhibition of the reattachment of young adult zebra mussels by single-species biofilms and associated exopolymers.

Aims: To determine the effects of single-species bacterial films and their associated extracellular products on the reattachment of young adult zebra mussels. Materials and Results: Ten strains of bacteria were isolated from surfaces where adult zebra mussels can be found attached in nature. Single-species biofilms were developed on both glass and polystyrene using these bacteria. The reattachment of zebra mussels (i.e. with byssal threads) was compared between surfaces with and without films. Although no differences were observed in mussel reattachment between glass surfaces with and without films (P > 0·05, anova), a reduction in mussel reattachment between polystyrene surfaces with and without films was observed for seven of the 10 strains (P ≤ 0·05 to <0·001, anova). Bacterial extracellular products (BEP) were isolated from five bacterial films and tested for their effects on mussel reattachment. Four of the five sets of isolated extracellular products evoked the same effects as their respective intact biofilms. Conclusions: We conclude that depending on the substratum, individual strains of bacteria in biofilms can inhibit the reattachment of adult zebra mussels. In some cases, BEP were the source of the inhibitory effects. Significance and Impact of the Study: The nature of the substratum on which the biofilms develop affects properties of the biofilm and its extracellular components, which subsequently influences zebra mussel reattachment.
Anatomic basis of the anterior surgery on the cervical spine: relationships between uncus-artery-root complex and vertebral artery injury

Vertebral artery injury is a serious complication during anterior surgery on the cervical spine. However, little information is available in the literature concerning the mechanism of vertebral artery laceration during the procedures of the anterior cervical decompression. In the current study twenty-eight cadavers were dissected to determine the location and relationships of the fibro-ligamentous tissues to the uncinate process, vertebral artery and nerve roots from the C3 to C6 levels. The vertebral artery and nerve root are encased by a fibro-ligamentous band at the level of the intertransverse space. This fibro-ligamentous band is attached to the lateral aspect of the uncinate process and uncovertebral joint, which combines the vertebral artery, nerve root and uncinate process to form a complex or unit. The fibro-ligamentous tissues between the uncovertebral joint and vertebral artery may explain the propensity to vertebral artery laceration during resection of the uncinate process or an osteophyte projecting from the uncovertebral joint. For this reason, the authors recommend that before resection of the uncinate process or uncovertebral joint is performed, it is necessary to thoroughly dissect the fibro-ligamentous tissues off the uncinate process.
Stretch-induced fetal type II cell differentiation is mediated via ErbB1 - ErbB4 interactions

Stretch-induced differentiation of lung fetal type II epithelial cells is mediated through EGFR (ErbB1) via release of HB-EGF and TGF-α ligands. Employing an EGFR knock-out mice model, we further investigated the role of the ErbB family of receptors in mechanotranduction during lung development. Deletion of EGFR prevented endogenous and mechanical stretch-induced type II cell differentiation via the ERK pathway, which was rescued by overexpression of a constitutively active MEK. Interestingly, the expression of ErbB4, the only ErbB receptor that EGFR co-precipitates in wild-type cells, was decreased in EGFR-deficient type II cells. Similar to EGFR, ErbB4 was activated by stretch and participated in ERK phosphorylation and type II cell differentiation. However, neuregulin (NRG) or stretch-induced ErbB4 activation were blunted in EGFR-deficient cells and not rescued after ErbB4 overexpression, suggesting that induction of ErbB4 phosphorylation is EGFR-dependent. Finally, we addressed how shedding of ligands is regulated by EGFR. In knock-out cells, TGF-α, a ligand for EGFR, was not released by stretch, while HB-EGF, a ligand for EGFR and ErbB4, was shed by stretch although to a lower magnitude than in normal cells. Release of these ligands was inhibited by blocking EGFR and ERK pathway. In conclusion, our studies show that EGFR and ErbB4 regulate stretch-induced type II cell differentiation via ERK pathway. Interactions between these two receptors are important for mechanical signals in lung fetal type II cells. These studies provide novel insights into the cell signaling mechanisms regulating ErbB family receptors in lung cell differentiation.
Efficient Synthesis of (±)-Erysotramidine Using an NBS-Promoted Cyclization Reaction of a Hexahydroindolinone Derivative

An NBS-promoted intramolecular electrophilic aromatic substitution reaction of a hexahydroindolinone derivative was used to assemble the tetracyclic core of the erythrinane skeleton. The resulting cyclized product was transformed into (±)-erysotramidine in three additional steps. The cyclization reaction is also successful using variously substituted aryl and furanyl bicyclic lactams under acidic conditions.
Patient-reported Outcomes of Breast Reconstruction after Mastectomy: a Systematic Review

Breast reconstruction is commonly utilized after mastectomy for breast cancer and is generally felt to improve women’s quality of life and well-being.1 However, most studies that have evaluated breast reconstruction have focused on outcomes that may not be relevant to patients or that are of interest primarily to surgeons (such as fat necrosis, symmetry without clothing),2–4 and many studies have not compared outcomes of breast reconstruction to outcomes of mastectomy only. In addition, recent findings of large geographic variations in rates of breast reconstruction have called into question the appropriateness of who gets breast reconstruction.5–8 Thus, our understanding of the impact of breast reconstruction on women’s lives remains somewhat limited. The purpose of this systematic review is to evaluate studies examining patient-reported outcomes of breast reconstruction after mastectomy for breast cancer, compared to mastectomy only.
Corporate Interest and Trade Liberalization The North American Free Trade Agreement and Environmental Protection

This article examines rhetoric by corporations about the inclusion of environmental issues in the North American Free Trade Agreement (NAFTA). It provides a greater understanding of corporate pressure on regulatory measures by indicating how corporate actions change in relation to social movement and state actions. The author develops a cultural political economy perspective to show how issues are not fixed but are shaped by power relations and ongoing meaning construction. In doing so, he argues for the integration of theories of the firm with theories of the state to reveal the relationship between organizations and their social and political environment. The author shows how corporate rhetoric in the NAFTA debate does not fit neatly into prevailing theories of organizational and political sociology and suggests, instead, a political economy perspective that indicates a dynamic cultural process by which corporations attempt to ensure profit maximization under changing circumstances.
An Implicit 2-D Shallow Water Flow Model on Unstructured Quadtree Rectangular Mesh

Abstract An implicit finite volume scheme is developed to solve the depth-averaged 2-D shallow water flow equations. The computational mesh consists of rectangular cells, with quadtree technology incorporated to locally refine the mesh around structures of interest or where the topography and/or flow properties change sharply. The grid nodes are numbered by means of an unstructured index system for more flexibility. The governing equations are solved using the SIMPLEC algorithm on non-staggered grid to handle the coupling of water level and velocity. In this non-staggered system, primary variables u-, v-velocity, and water level are stored on the same set of grid points, and fluxes at cell faces are determined using the Rhie and Chow's momentum interpolation method to avoid spurious checkerboard oscillations. The discretized algebraic equations are solved iteratively using the GMRES method. The model has been tested against measurement data for steady flow around a spur-dyke in a laboratory flume and tida...
Enhanced Schawlow-Townes linewidth in lasers with nonorthogonal transverse eigenmodes

A recent reformulation of the laser field equations using the true modes of the laser cavity and including a noise polarization term to account for spontaneous emission shows that conventional understanding of amplifier noise figure oscillator linewidth and oscillator build-up time needs to be modified for laser amplifiers or oscillators with nonorthogonal transverse eigenmodes. Gain-guided lasers and unstable-resonator lasers in particular have nonorthogonal transverse modes and hence exhibit unconventional noise behavior. One important consequence of this theory is the appearance of an excess spontaneous emission factor (the " Petermann factor" ) which multiplies the well-known Schawlow-Townes formula for the laser linewidth. This factor can be substantially greater than unity for unstable resonators with large magnification or Fresnel number. We discuss our investigations of the consequences of the nonorthogonality of the transverse eigenmodes especially on laser linewidth in unstable-resonator lasers. We believe that the results of these investigations are important where the temporal coherence properties of the laser are of interest namely in coherent optical communications spectroscopy optical wavelength standards and also in the injection seeding of pulsed high-power unstable resonator lasers. Extensive calculations of the excess noise factor in real hard-edged unstable resonators have been carried out using a virtual-source approach to calculate the exact unstable-resonator eigenmodes. An experiment is also being carried out to demonstrate the linewidth enhancement in a small diode-pumped geometrically unstable laser oscillator.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Synthetic Lethal Screening with Small-Molecule Inhibitors Provides a Pathway to Rational Combination Therapies for Melanoma

Recent data demonstrate that extracellular signals are transmitted through a network of proteins rather than hierarchical signaling pathways suggesting why inhibition of a single component of a canonical pathway is insufficient for the treatment of cancer. The biological outcome of signaling through a network is inherently more robust and resistant to inhibition of a single network component. In this study, we performed a functional chemical genetic screen to identify novel interactions between signaling inhibitors that would not be predicted based on our current understanding of signaling networks. We screened over 300 drug combinations in nine melanoma cell lines and have identified pairs of compounds that show synergistic cytotoxicity. The synergistic cytotoxicities identified did not correlate with the known RAS and BRAF mutational status of the melanoma cell lines. Among the most robust results was synergy between sorafenib, a multi-kinase inhibitor with activity against RAF, and diclofenac, a non-steroidal anti-inflammatory drug (NSAID). Drug substitution experiments using the NSAIDs celecoxib and ibuprofen or the MEK inhibitor PD325901 and the RAF inhibitor RAF265 suggest that inhibition of cyclooxygenase (COX) and MAP kinase signaling are targets for the synergistic cytotoxicity of sorafenib and diclofenac. Co-treatment with sorafenib and diclofenac interrupts a positive feedback signaling loop involving ERK, cPLA2, and COX. Genome-wide expression profiling demonstrates synergy-specific down-regulation of survival-related genes. This study has uncovered novel functional drug combinations and suggests that the underlying signaling networks that control responses to targeted agents can vary substantially depending on unexplored components of the cell genotype.
Equity ownership and the two faces of debt

We empirically investigate the relation between corporate value, leverage, and equity ownership. For ‘high-growth’ firms corporate value is negatively correlated with leverage, whereas for ‘low-growth’ firms corporate value is positively correlated with leverage. The results also hint that the allocation of equity ownership among insiders, institutions, blockholders, and atomistic outside shareholders is of marginally greater significance in low-growth than in high-growth firms. The overall interpretation of the results is that debt policy and equity ownership structure ‘matter’ and that the way in which they matter differs between firms with many and firms with few positive net present value projects.
Caring for Terminally ILL Persons: Comparative Analysis of Attitudes (Thanatophobia) of Practicing Physicians, Student Nurses, and Medical Students:

To investigate why some caregivers desire to avoid patients with terminal illnesses, a thanatophobia scale assessing caregivers' uncomfortable feelings and sense of helplessness was developed and e...
Spatial distribution of intracortical porosity varies across age and sex

Cortical bone porosity is a major determinant of strength, stiffness, and fracture toughness of cortical tissue. The goal of this work was to investigate changes in spatial distribution and microstructure of cortical porosity associated with aging in men and women. The specific aims were to: 1) develop an automated technique for spatial analysis of cortical microstructure based on HR-pQCT data, and; 2) apply this technique to explore sex- and age-specific spatial distribution and microstructure of porosity within the cortex. We evaluated HR-pQCT images of the distal tibia from a cross-sectional cohort of 145 individuals, characterizing detectable pores as being in the endosteal, midcortical, or periosteal layers of the cortex. Metrics describing porosity, pore number, and pore size were quantifiedwithin each layer and compared across sexes, age groups, and cortical layers. The elderly cohort (65–78 years, n=22) displayed higher values than the young cohort (20–29 years, n=29) for all parameters both globally and within each layer. While all three layers displayed significant age-related porosity increases, the greatest difference in porosity between the young and elderly cohort was in the midcortical layer (+344%, p < 0.001). Similarly, the midcortical layer reflected the greatest differences between young and elderly cohorts in both pore number (+243%, p < 0.001) and size (+28%, p < 0.001). Females displayed greater age-related changes in porosity and pore number than males. Females and males displayed comparable small to non-significant changes with age in pore size. In summary, considerable variability exists in the spatial distribution of detectable cortical porosity at the distal tibia, and this variability is dependent on age and sex. Intracortical pore distribution analysis may ultimately provide insight into both mechanisms of pore network expansion and biomechanical consequences of pore distribution.
An operating framework design for web-based collections of scientific digital objects

The primary objective of web-based collections of scientific arbitrary digital objects is to increase the distribution of the objects within the collection. Other priorities include providing a systematic organization of the objects, a means to catalogue and manage them, and user interfaces to discover, display, and retrieve items from the collection. These objectives require an advanced operating framework, consisting of multiple components that run under heterogeneous environments. The framework must operate using web protocols such as http, browser and server standards, database communication languages such as sql and middle layer communication methods such as Java or CGI. A generic operating framework is described here which provides many of the features needed to manage and operate a collection. Several of the features and associated methodologies are discussed including user services, system and application metadata schemes, database integration data-handling systems, and interoperability with distributed collections. Relevant policy issues pertaining to the collection management and intellectual property rights are also addressed.
Hepatic surgery at a VA tertiary medical center: lessons learned

Abstract Background The development of a hepatic surgery center within a US Department of Veterans Affairs hospital is dependent on proper training and institutional support, which can translate into low operative morbidity and mortality rates. Methods Patients who underwent hepatic procedures between 2003 and 2009 were retrospectively reviewed. A subset analysis of laparoscopic liver resections for patients with hepatocellular cancer (HCC) was performed. One hundred twenty-six patients underwent 130 hepatic procedures, 65% of which were hepatic resections. Ninety-seven percent of cases were for malignant disease, including HCC (70%). Results The morbidity and mortality rates were 15.5% and 2.4%, respectively. For patients with HCC there was no difference in operative outcomes or overall survival when procedures were performed laparoscopically. Conclusions A Veterans Affairs (VA) hospital specializing in hepatic surgery can achieve low complication rates comparable with those of high-volume centers. The numbers of patient referrals and hepatic resections and the proportion of laparoscopic operations increased after the creation of a dedicated hepatic surgery center within a single VA hospital.
Development of ZnO:Ga as an Ultra-Fast Alpha Particle Detector

We report on ZnO:Ga to produce a high luminosity, ultra fast alpha detector as a system component that provides associated particle imaging (API) capability to neutron generators. ZnO:Ga has been shown to be well suited as the scintillator screen of the detector. Fast luminescence is observed but its intensity and decay time is strongly dependent on the method used for dopant incorporation. We compare samples made by diffusion of Ga metal to samples doped by solid state reaction with Ga2O3 followed by reduction in hydrogen. The ZnO:Ga prepared with reduction of Ga2O3 has a strong blue photoluminescence and a fast decay of the x-ray excited luminescence. The luminosity of the material increases dramatically at cryogenic temperatures. We also present the results of an alternate low-temperature synthesis that produces luminescent particles with a more uniform size distribution.
Phase-pulling effects in forward Raman scattering

Phase-pulling effects in transient stimulated Raman scattering of forward-propagating plane-wave fields are examined both analytically and numerically. The Stokes temporal phase profile is found to lock very quickly to a final (output) temporal phase profile, once the Stokes-field intensity has grown to roughly 1 order of magnitude greater than the initial Stokes seed intensity. The final temporal phase profile of the output Stokes field is pulled to the phase of the input pump (Stokes) field when the medium relaxation time is large (small) relative to the time scale of the input phase variations. For intermediate relaxation times, the output Stokes temporal profile also locks quickly but to a profile that is that of neither the input pump nor the input Stokes. The output Stokes phase is found to be relatively insensitive to pump transverse intensity variations.
Compressive sensing with optimal sparsifying basis and applications in spectrum sensing

We describe a method of integrating Karhunen-Loeve Transform (KLT) into compressive sensing, which can as a result improve the compression ratio without affecting the accuracy of decoding. We present two complementary results: 1) by using KLT to find an optimal basis for decoding we can drastically reduce the number of measurements for compressive sensing used in applications such as radio spectrum analysis; 2) by using compressive sensing we can estimate and recover the KLT basis from compressive measurements of an input signal. In particular, we propose CS-KLT, an online estimation algorithm to cope with nonstationarity of wireless channels in reality. We validate our results with empirical data collected from a wideband UHF spectrum and field experiments to detect multiple radio transmitters, using software-defined radios.
Spectral Estimates of Gravity Wave Energy and Momentum Fluxes. Part I: Energy Dissipation, Acceleration, and Constraints

Abstract The spectral characteristics of atmospheric gravity wave motions are remarkably uniform in frequency and wavenumber despite widely disparate sources, filtering environments, and altitudes of observation. This permits a convenient and useful means of describing mean spectral parameters, including energy density, anisotropy, energy and momentum fluxes, and wave influences on their environment. The purpose here is to provide a general formulation of the mean energy spectrum as well as estimates of the wave energy and momentum fluxes and the flux divergences expressed as the energy dissipation rate and the induced accelerations in the lower and middle atmosphere. These results show spectral observations to be consistent with independent estimates of energy dissipation rates and to suggest a high degree of anisotropy of the gravity wave field under conditions of strong wave filtering by large-scale, low-frequency motions. In two companion papers, these results are employed to construct a parameterizat...
Analysis of GaAs MESFET spectrum regeneration driven by a /spl pi//4-DQPSK modulated source

A new method of analyzing transistor nonlinearity in the context of digital modulation is proposed. Classical methods of nonlinearity analysis, such as the third-order intercept point, are ill-suited for systems based on digitally modulated signals. The third-order intercept point ignores higher-order effects and latent out-of-channel power, both of which affect spectrum regeneration. Using a power spectral density description of the source, coupled with a simplified Volterra series model of a GaAs MESFET, it is shown that reactive nonlinearity contributes to spectrum regeneration. Subsequently, insight is gained at the device level for doping/implant improvements and at the terminal level for optimal loading, resulting in improved linearity. >
Review: fair evidence supports several tests in investigating fever of unknown origin.

Source Citation Mourad O, Palda V, Detsky AS. A comprehensive evidence-based approach to fever of unknown origin. Arch Intern Med. 2003;163:545-51. 12622601
Assessing performance of an Electronic Health Record (EHR) using Cognitive Task Analysis.

Abstract Background Many Electronic Health Record (EHR) systems fail to provide user-friendly interfaces due to the lack of systematic consideration of human-centered computing issues. Such interfaces can be improved to provide easy to use, easy to learn, and error-resistant EHR systems to the users. Objective To evaluate the usability of an EHR system and suggest areas of improvement in the user interface. Methods The user interface of the AHLTA (Armed Forces Health Longitudinal Technology Application) was analyzed using the Cognitive Task Analysis (CTA) method called GOMS (Goals, Operators, Methods, and Selection rules) and an associated technique called KLM (Keystroke Level Model). The GOMS method was used to evaluate the AHLTA user interface by classifying each step of a given task into Mental (Internal) or Physical (External) operators. This analysis was performed by two analysts independently and the inter-rater reliability was computed to verify the reliability of the GOMS method. Further evaluation was performed using KLM to estimate the execution time required to perform the given task through application of its standard set of operators. Results The results are based on the analysis of 14 prototypical tasks performed by AHLTA users. The results show that on average a user needs to go through 106 steps to complete a task. To perform all 14 tasks, they would spend about 22 min (independent of system response time) for data entry, of which 11 min are spent on more effortful mental operators. The inter-rater reliability analysis performed for all 14 tasks was 0.8 (kappa), indicating good reliability of the method. Conclusion This paper empirically reveals and identifies the following finding related to the performance of AHLTA: (1) large number of average total steps to complete common tasks, (2) high average execution time and (3) large percentage of mental operators. The user interface can be improved by reducing (a) the total number of steps and (b) the percentage of mental effort, required for the tasks.
A Comparison of Freezing Injury in Oat and Rye: Two Cereals at the Extremes of Freezing Tolerance

A detailed analysis of cold acclimation of a winter rye (Secale cereale L. cv Puma), a winter oat (Avena sativa L. cv Kanota), and a spring oat cultivar (Ogle) revealed that freezing injury of leaves of nonacclimated seedlings occurred at -2[deg]C in both the winter and spring cultivars of oat but did not occur in winter rye leaves until after freezing at -4[deg]C. The maximum freezing tolerance was attained in all cultivars after 4 weeks of cold acclimation, and the temperature at which 50% electrolyte leakage occurred decreased to -8[deg]C for spring oat, -10[deg]C for winter oat, and -21[deg]C for winter rye. In protoplasts isolated from leaves of nonacclimated spring oat, expansion-induced lysis was the predominant form of injury over the range of -2 to -4[deg]C. At temperatures lower than -4[deg]C, loss of osmotic responsiveness, which was associated with the formation of the hexagonal II phase in the plasma membrane and subtending lamellae, was the predominant form of injury. In protoplasts isolated from leaves of cold-acclimated oat, loss of osmotic responsiveness was the predominant form of injury at all injurious temperatures; however, the hexagonal II phase was not observed. Rather, injury was associated with the occurrence of localized deviations of the plasma membrane fracture plane to closely appressed lamellae, which we refer to as the "fracture-jump lesion." Although the freeze-induced lesions in the plasma membrane of protoplasts of spring oat were identical with those reported previously for protoplasts of winter rye, they occurred at significantly higher temperatures that correspond to the lethal freezing temperature.
Photoaffinity Analog of the Semisynthetic Echinocandin LY303366: Identification of Echinocandin Targets in Candida albicans

The echinocandins are a family of cyclic lipopeptides with potent antifungal activity. These compounds inhibit the synthesis of BETA-1,3-glucan in fungi. The new semisynthetic echinocandin LY303366 was derivatized to produce a photoactivatable cross-linking echinocandin analog with antifungal activity. This analog was radioiodinated and used as a probe in microsomal membrane preparations of Candida albicans which contain glucan synthase activity. The photoaffinity probe identified two major proteins of 40 and 18 kDa in both membrane preparations. Labeling of these proteins was specific in that it required irradiation with UV light and was effectively competed against with unlabeled echinocandin analogs. In addition, the abilities of echinocandin analogs to compete with the photoaffinity probe correlated to their relative antifungal potencies and glucan synthase inhibition. The 40-kDa protein was isolated, and partial sequences were obtained from internal peptide fragments of the protein. Analysis of the sequences of these internal peptides of the 40-kDa protein revealed that it was a new protein not previously described as being involved in glucan synthesis or the mode of action of echinocandins.
The Maine Question How Is 4-Year College Enrollment Affected by Mandatory College Entrance Exams?

We use a difference-in-differences analytic approach to estimate postsecondary consequences from Maine’s mandate that all public school juniors take the SAT®. We find that, overall, the policy increased 4-year college-going rates by 2- to 3-percentage points and that 4-year college-going rates among induced students increased by 10-percentage points.
Radon as a tracer of biogenic gas equilibration and transport from methane-saturated sediments

Data on Rn-222 activity in methane-rich gas bubbles from anoxic coastal sediments of Cape Lookout Bight, North Carolina, were used to determine gas equilibration with pore waters and the rates of ebullitive stripping and transport of gases to overlying waters and the atmosphere. Results showed that, during summer months, the bubble ebullition process strips and transports 1.9-4.8 percent/day of the standing crop of radon (and, by inference, other gases equilibrated with gas bubbles) in surface sediments of Cape Lookout Bight to the troposphere. Thus, the ebullitive mode of gas transport represents an effective mechanism for delivering reduced biogenic gases directly to the atmosphere.
Cell-Specific Expression of the Rat Secretogranin II Promoter*

Secretogranin II (SgII) is a member of the granin family of secretory proteins, which are selectively expressed in neuroendocrine cells. As a first step in understanding the molecular basis for cell type-specific expression of SgII, we isolated a 12-kb clone from a rat genomic library that contained the entire rat SgII coding region, the transcription initiation site, and approximately 3 kb of 5'-flanking region. Within 75 bp of the transcription start site (+1) we located a TATA box and a consensus cAMP responsive element. Within the 5'-flanking region, a number of potential cis-acting elements were identified, including 2 Pit-1 binding sites, 15 E box motifs, and near-perfect matches for AP-1 and AP-2 sites. To demonstrate cell type-specific expression the rat SgII gene, a plasmid containing 2.6 kb of the 5'-flanking region of the SgII gene fused to the luciferase reporter gene (p2774Luc) was transfected into rat pheochromocytoma PC-12 cells, rat pituitary GH4C1 (GH) cells, human BE(2)-M17 (M17) neurobl...
Higher northern latitude normalized difference vegetation index and growing season trends from 1982 to 1999

Normalized difference vegetation index data from the polar-orbiting National Oceanic and Atmospheric Administration meteorological satellites from 1982 to 1999 show significant variations in photosynthetic activity and growing season length at latitudes above 35 degrees N. Two distinct periods of increasing plant growth are apparent: 1982-1991 and 1992-1999, separated by a reduction from 1991 to 1992 associated with global cooling resulting from the volcanic eruption of Mt. Pinatubo in June 1991. The average May to September normalized difference vegetation index from 45 degrees N to 75 degrees N increased by 9% from 1982 to 1991, decreased by 5% from 1991 to 1992, and increased by 8% from 1992 to 1999. Variations in the normalized difference vegetation index were associated with variations in the start of the growing season of -5.6, +3.9, and -1.7 days respectively, for the three time periods. Our results support surface temperature increases within the same period at higher northern latitudes where temperature limits plant growth.