cssi/SciSciGPT-SciSciNet huggingface dataset:
Debridement of Chronic Wounds: A Qualitative Systematic Review of Randomized Controlled Trials

This article reviews the current evidence available regarding wound debridement of chronic wounds and collates data from existing randomized controlled trials.
Sealskins and Original Dimes: Exploitation, Class, and Commodity Fetishism in Toni Morrison's Tar Baby

Throughout Tar Baby, Morrison makes use of the original tar baby story in order to underscore the relationship between exploitation, commodity consumption, and social and economic domination. Commodities are presented as a dual snare that lead the novel's characters to pursue self-negating, individualistic activities and to repress the exploitative origins of wealth.
Evaluating the purity of a 57Co flood source by PET

Purpose: Flood sources of 57Co are commonly used for quality control of gamma cameras. Flood uniformity may be affected by the contaminants 56Co and 58Co, which emit higher energy photons. Although vendors specify a maximum combined 56Co and 58Co activity, a convenient test for flood source purity that is feasible in a clinical environment would be desirable. Methods: Both 56Co and 58Co emit positrons with branching 19.6% and 14.9%, respectively. As is known from 90Y imaging, a positron emission tomography (PET) scanner is capable of quantitatively imaging very weak positron emission in a high single-photon background. To evaluate this approach, two 57Co flood sources were scanned with a clinical PET/CT multiple times over a period of months. The 56Co and 58Co activity was clearly visible in the reconstructed PET images. Total impurity activity was quantified from the PET images after background subtraction of prompt gamma coincidences. Results: Time-of-flight PET reconstruction was highly beneficial for accurate image quantification. Repeated measurements of the positron-emitting impurities showed excellent agreement with an exponential decay model. For both flood sources studied, the fit parameters indicated a zero intercept and a decay half-life consistent with a mixture of 56Co and 58Co. The total impurity activity at the reference date was estimated to be 0.06% and 0.07% for the two sources, which was consistent with the vendor’s specification of <0.12%. Conclusions: The robustness of the repeated measurements and a thorough analysis of the detector corrections and physics suggest that the accuracy is acceptable and that the technique is feasible. Further work is needed to validate the accuracy of this technique with a calibrated high resolution gamma spectrometer as a gold standard, which was not available for this study, and for other PET detector models.
Gaussian-to-Bessel beam transformation using a split refracting system

A two-element refracting system is designed to transform a Gaussian laser beam into a diffraction-free Bessel beam. The resulting input and output surfaces are almost spherical, which makes for easy implementation of the system.
The Sutter's Mill meteorite: Thermoluminescence data on thermal and metamorphic history

A piece of the Sutter's Mill meteorite, fragment SM2-1d, has been examined using thermoluminescence techniques to better understand its thermal and metamorphic history. The sample had very weak but easily measureable natural and induced thermoluminescence (TL) signals; the signal-to-noise ratio was better than 10. The natural TL was restricted to the high-temperature regions of the glow curve suggesting that the meteorite had been heated to approximately 300 °C within the time it takes for the TL signal to recover from a heating event, probably within the last 105 years. It is possible that this reflects heating during release from the parent body, close passage by the Sun, or heating during atmospheric passage. Of these three options, the least likely is the first, but the other possibilities are equally likely. It seems that temperatures of approximately 300 °C reached 5 or 6 mm into the meteorite, so that all but one of the small Sutter's Mill stones have been heated. The Dhajala normalized induced TL signal for SM2-1d is comparable to that of type 3.0 chondrites and is unlike normal CM chondrites, the class it most closely resembles, which do not have detectable TL sensitivity. The shape of the induced TL curve is comparable to other low-type ordinary, CV, and CO chondrites, in that it has a broad hummocky structure, but does not resemble any of them in detail. This suggests that Sutter's Mill is a unique, low-petrographic–type (3.0) chondrite.
Race/ethnicity and age-related macular degeneration.

a t n “ p o t A GE-RELATED MACULAR DEGENERATION (AMD) HAS long been thought to be more frequent in nonHispanic whites than in blacks in the United States. This was based on observations reported in clinical case series. The use of new AMD classification schemes and severity scales in large population-based studies has confirmed that non-Hispanic whites have higher prevalences of late AMD, both neovascular AMD and geographic atrophy, than in non-Hispanic blacks and Hispanics. For example, in the Salisbury Eye Examination (SEE), the prevalence of neovascular AMD (1.7% vs 1.1%) and geographic atrophy (1.8% vs 0.3%) was higher in whites than in blacks. Age-specific prevalence of late AMD was consistently lower in Mexican Americans in the Los Angeles Latino Eye Study (LALES) than in whites in the Beaver Dam Eye Study (BDES) (eg, 70-79 years, 1.5% vs 3.7%; 80 years, 8.5% vs .5%). In the Multi-Ethnic Study of Atherosclerosis (MESA), the prevalence of late AMD was higher in Chinese Americans than in whites. Similar risk factors, for example older age, family history, and smoking, were associated with AMD regardless of race/ethnicity. There are few population-based studies describing the incidence or progression of AMD in different racial/ethnic groups. These studies, using newer standardized grading schemes, have shown that while younger non-Hispanic blacks and Mexican Americans manifest early AMD with almost the same prevalence as in whites, they are less likely to develop late AMD than non-Hispanic whites. In the SEE, blacks were more likely than whites to develop early AMD after 2 years of follow-up examination but had similar risk of progression to more severe AMD. Over a 9-year period in the population-based Barbados Eye Study, the overall incidence rate of early AMD in blacks was 13% and that of late AMD was 0.7%, significantly lower than found in whites in the BDES, a white population of similar age. In the LALES, the 4-year incidence of both early (7.5%) and late (0.2%) AMD was significantly lower than the estimated incidence in non-Hispanic whites in the BDES. When the data were age-standardized, the
Prediction of upper extremity impact forces during falls on the outstretched hand

Among the most common causes of upper extremity fracture is a fall on the outstretched hand. Yet few data exist on the biomechanical factors which affect injury risk during this event. In this study, we measured impact forces during low-height (0-5 cm), forward falls onto the outstretched hand, and found that these are governed by an initial high-frequency peak and a subsequent, lower-frequency oscillation. This behavior was well-simulated by a two-degree-of-freedom, lumped-parameter mathematical model. Increases in body mass caused greater increases in the peak magnitude of the low-frequency component (Fmax2) than the high-frequency component (Fmax1). However, increases in fall height more strongly influenced Fmax1, which exceeded Fmax2 for all but very low fall heights. Model predictions suggest that fall heights greater than 0.6 m carry significant risk for wrist fracture, since above this height, peak forces surpass the average fracture force of the distal radius. Finally, while the shoulder experiences lower peak force than the wrist (since Fmax1 is not transmitted proximally), it undergoes considerably greater deflection, and thereby absorbs the majority of impact energy during a fall.
On approximating the distributions ofFriedman's 75-175-175-1and related statistics

Error bounds depending explicitly on parameters of the problem are given for large-sample approximations to the central and noncentral distributions ofFriedman's [1937]xr2 statistic,Steel's [1959] statistics for comparingr treatments with a control, andNemenyi's [1963] statistics for pair-wise comparisons among all treatments. These bounds are of ordero(N−1/2); an improved bound of ordero (N−r/(r+1)) is given forFriedman's statistic in the central case. Applications yield bounds on the actual type 1 and type 2 error probabilities in terms of their normal-theory approximations.
Flow Disturbance Measurements in the National Transonic Facility

Recent flow measurements have been acquired in the National Transonic Facility to assess the test-section unsteady flow environment. The primary purpose of the test is to determine the feasibility of the facility to conduct laminar-flow-control testing and boundary-layer transition-sensitive testing at flight-relevant operating conditions throughout the transonic Mach number range. The facility can operate in two modes, warm and cryogenic test conditions for testing full and semispan-scaled models. Data were acquired for Mach and unit Reynolds numbers ranging from 0.2≤M≤0.95 and 3.3×106<Re/m<220×106 collectively at air and cryogenic conditions. Measurements were made in the test section using a survey rake that was populated with 19 probes. Roll polar data at selected conditions were obtained to look at the uniformity of the flow disturbance field in the test section. Data acquired included mean total temperatures, mean and fluctuating static/total pressures, and mean and fluctuating hot-wire measurements...
Characterization of a New Family of Nonwettable, Nonstick Surfaces

Two examples of a new family of water-based, nonstick, hydrophobic polymeric coatings were used to relate wettability to surface composition and adhesion. They were prepared by cross-linking reacti...
Arterial Blood Flow Measurement Using Digital Subtraction Angiography (DSA)

Standard angiography demonstrates the anatomy of arterial occlusive disease but not its physiological signficance. Using intravenous digital subtraction angiography (DSA), we investigated transit-time videodensitometric techniques in measuring femoral arterial flows in dogs. These methods have been successfully applied to intraarterial DSA but not to intravenous DSA. Eight 20 kg dogs were instrumented with an electromagnetic flow probe and a balloon occluder above an imaged segment of femoral artery. 20 cc of Renografin 76 was power injected at 15 cc/sec into the right atrium. Flow in the femoral artery was varied by partial balloon occlusion or peripheral dilatation following induced ischemia resulting in 51 flow measurements varying from 15 to 270 cc/min. Three different transit-time techniques were studied: crosscorrelation, mean square error, and two leading edge methods. Correlation between videodensitometry and flowmeter measurements using these different techniques ranged from 0.78 to 0.88 with a mean square error of 29 to 37 cc/min. Blood flow information using several different transit-time techniques can be obtained with intravenous DSA.
Clonality assessment of cutaneous B-Cell lymphoid proliferations: A comparison of flow cytometry immunophenotyping, molecular studies, and immunohistochemistry/in situ hybridization and review of the literature

Cutaneous lymphoid infiltrates are diagnostically challenging. Although ancillary techniques to assess clonality can help distinguish between reactive lymphoid hyperplasia and lymphoma, one of the most widely used techniques in hematopathology, flow cytometry immunophenotyping (FCI), has not been routinely applied to skin specimens. We performed FCI on 73 skin specimens from 67 patients clinically suspected of having a cutaneous B-cell lymphoma (CBCL) and compared the results with those obtained from immunoglobulin heavy chain (IGH) gene molecular studies (58 cases, primarily by polymerase chain reaction) and either immunohistochemistry (IHC) or in situ hybridization to evaluate for light chain restriction (22 and 2 cases, respectively). Sufficient quantity of CD45 (leukocyte common antigen)-positive cells and staining quality were achieved in 88% of cases by FCI, and clonality was detected in 68% of CBCLs versus molecular studies showing sufficient DNA quality in 74% and only 39% clonality detection, and interpretable/contributory IHC results in 84% of cases with 55% clonality detection. Clonality was documented more frequently in secondary rather than primary CBCLs by all 3 techniques. Therefore, FCI is feasible and appears to be more reliable than molecular studies or IHC/in situ hybridization for detecting clonality in CBCLs and can provide additional prognostically and therapeutically relevant information. The exception is cases with plasmacytic differentiation such as marginal zone lymphoma for which IHC might be a superior tool. We have also shown that a large subset of primary cutaneous follicle center lymphomas express CD10 and/or BCL2 by FCI. Recent advances in FCI beg the question of applicability to cutaneous T-cell and NK-cell lymphomas.
Plasmon resonant structures with unique topographic characteristics and tunable optical properties for surface-enhanced Raman scattering

A simple, inexpensive, parallel approach has been developed for scalable large-area fabrication of two-dimensional (2D) periodic arrays of plasmon resonant structures. This method allows engineering of plasmon modes through precise tailoring of the structural parameters of metal nanostructures for reproducible Raman enhancement.
Multi-Fiber Unit Cell for Prediction of Residual Stresses in Continuous Fiber Composites.

The mechanical properties of Continuous Fiber Metal Matrix Composite (CFMMC) materials are often affected by the residual stresses that arise during their fabrication process as a result of the mismatch between the Coefficients of Thermal Expansion (CTE) of the fibers and matrix. Three-dimensional finite element Unit Cell Models (UCM) are commonly used to predict such residual stress fields. However, the boundary conditions chosen in the past for these models neglect the effects of interactions between neighboring fibers, which results in poor correlations with experimental results. Previous research shows that the UCM approach usually overestimates the residual stress levels by about 30%. In this paper, two new three-dimensional finite element Multi Fiber Models (MFM) are developed in which the boundary conditions are shifted away from the fiber-matrix interface, in order to account for the effects of neighboring fibers on the stress distribution over such interfaces. One model assumes a hexagonal packin...
Periodic solutions of heat transfer for flow through a periodic assemblage of spheres

Transfert thermique et ecoulement a travers un reseau de spheres de memes dimensions et equidistantes represente par un modele de cellule cylindrique a plusieurs spheres. Dans ce modele plusieurs spheres en tandem sont enfermees dans une conduite cylindrique
Effects of Goal Type on Performance, Task Interest, and Affect Over Time1

The purpose of this study was to increase understanding regarding the effects of goal-setting practices on a wide range of dependent variables over time. Goal type (control group, quality goal, quantity goal, and dual goal) was manipulated across 3 time periods. Goal × Time interactions were predicted such that quantity, effort, task interest, and positive affect would initially be low, but by later trials would be higher in the quantity and dual-goal conditions compared to the quality goal and control groups. Quality was expected to be greatest in the quality goal condition and to be relatively constant over time. Participants (N= 80) were undergraduates at a large midwestern university. Results indicated some support for our hypotheses in that Goal × Time interactions were found for quantity produced, rated effort, task interest, and positive affect.
Initiation of the spring bloom in the northeast Atlantic (47°N, 20°W): a numerical simulation

We have applied a mixed layer model and a simple biological model to examine spring phytoplankton increase observed during the North Atlantic Bloom Experiment of the Joint Global Ocean Flux Study. Despite spatial variability in water column conditions, the one-dimensional mixed-layer model (Priceet al., Journal of Geophysical Research, 91, 8411–8427, 1986) reproduced satisfactorily the increasing stratification during the 2-week observation period. Likewise, the gradient and extent of nutrient removal (exemplified by nitrate) and the timing of the increase in phytoplankton biomass (represented by chlorophyll α) compared reasonably well between the model and observations. The cell-quota formulation for phytoplankton growth, and an adaptive feeding model for zooplankton appear to be necessary to accord with the observations. On the other hand, adaptive feeding by zooplankton makes the model sensitive to the choice of a maximum growth rate in phytoplankton. Zooplankton were probably not a factor early in the simulation, but according to the model, exerted significant grazing pressure by the end of the observational period.
Arenediazonium Salts: New Probes of the Compositions of Association Colloids. 7. Average Hydration Numbers and Cl- Concentrations in the Surfactant Film of Nonionic C12E5/Octane/Water Macroemulsions: Temperature and NaCl Concentration Effects†

A surface-active arenediazonium ion, 4-hexadecyl-2,6-dimethylbenzenediazonium ion, 16-ArN2+, was used as a chemical trapping probe of the concentrations of weakly basic nucleophiles in the surfactant film between the aqueous and oil domains of opaque relatively long-lived C12E5/octane/water macroemulsions as a function of temperature and added NaCl. The results demonstrate that the chemical trapping method “sees” the composition of the oligooxyethylene or interfacial layer on the aqueous side of the surfactant film. Product yields from trapping of the available nucleophiles, H2O, the terminal OH group of C12E5, and Cl-, were used to estimate average hydration numbers of all aggregates present in the macroemulsions as a function of increasing temperature and added NaCl. At 19.9 °C, the average hydration number in the macroemulsions is 2.5, compared to a 70% larger value of 4.2 in C12E6 micelles at 20 °C obtained previously by chemical trapping. Average hydration numbers decrease with increasing temperature...
Calculating quantum corrections to the mass of a soliton without collective coordinates

Abstract Feynman rules are derived for computing quantum corrections to the mass of a soliton in quantum field theory. These rules exhibit a finite propagator, but in contrast to previous methods, no additional effective vertices are introduced beyond those present in the original shifted Lagrangian. The derivation is based on imposing end-point boundary conditions appropriate to a soliton state on the functional integral representing the soliton-to-soliton transition amplitude.
Epitaxial Electrodeposition of Tin(II) Sulfide Nanodisks on Single-Crystal Au(100)

Epitaxial nanodisks of tin(II) sulfide (SnS) are deposited electrochemically on a [100]-oriented single-crystal Au substrate from an acidic solution at 70 °C. The SnS grows with two different out-of-plane orientations of [100] and [301], which each have four equivalent in-plane orientations. X-ray pole figures reveal the following epitaxial relationships: SnS(100)[010]//Au(100)[010], SnS(100)[010]//Au(100)[010], SnS(100)[010]//Au(100)[001], SnS(100)[010]//Au(100)[001], SnS(301)[010]//Au(100)[010], SnS(301)[010]//Au(100)[010], SnS(301)[010]//Au(100)[001], and SnS(301)[010]//Au(100)[001]. For the SnS[100] orientation, the in-plane mismatch is −2.4% in the [010] direction and 6.1% in the [001] direction. For the [301] orientation, the in-plane mismatch is −2.4% in the [010] direction and alternates between 3.4% and 6.7% in the [103] direction. The SnS deposits with a disklike morphology with a diameter of 300 nm and a thickness of 50 nm.
Recurrence of sums of multiple markov sequences

Ad-dimensional random walk on a lattice is studied in which each step is bounded, and may depend on the previousm steps. It is proved that if trivial cases are excluded, there are no recurrent points ford≧3, and conditions are given for the existence of sets, recurrent conditional on the firstm steps, ford=1, 2.
Isolated Pulmonary Goodpasture Syndrome

The case of a 13–year-old girl with Goodpasture syndrome is reported. The presentation at this age with only pulmonary hemorrhage is unusual among Goodpasture syndrome patients. The case illustrates well the diagnostic difficulties in Goodpasture syndrome. The choices of treatment modalities available for this disease and the results and risks of such treatment options are reviewed. A discussion and classification of diffuse pulmonary hemorrhage is presented. The case emphasizes that Goodpasture syndrome should be considered in the differential diagnosis of diffuse pulmonary hemorrhage in spite of a lack of renal abnormalities and that serum anti-glomerular basement membrane antibody testing can be of great help in confirming the diagnosis.
New questions about old heritability estimates

This note summarizes the main results of three recent studies on the heritability of mental traits: (1) The inferences Jinks and Fulker (1970) derived from Shields’s (1962) twin data are invalid since the assumptions of the genetic model are consistently violated by these data. A purely environmental model fits them better by a factor of 2. (2) Holzinger’s heritability coefficient (h2) is invalid since his derivations imply that dizygotic twins share no genes. (3) In contrast, Nichols’s (1965) heritability coefficient (HR) follows from a strictly additive genetic model. (4) However, the needed assumptions are consistently violated by Osborne’s (1980) personality data, which produce an excessive number of inadmissible HRs. A purely environmental model fits these data better by a factor of 14. Jointly, these results suggest that heritability estimates of mental traits in the literature should be viewed with caution.
Lower respiratory problems of the neonate.

The transition to extrauterine life Early recognition of abnormalities in the respiratory tract is of utmost importance for the successful management of critically ill foals. To recognize abnormal, the normal must be known. Immediately after birth, foals undergo several important physiologic and behavioral changes. Chief among these changes is the adaptation of the cardiovascular and respiratory systems to extrauterine life. The normal transition of the respiratory tract involves opening closed alveoli and absorption of fluid from the airway, accomplished by a combination of breathing efforts, expiration against a closed glottis (‘‘grunting’’), and a change in sodium flux across the respiratory membrane from net secretion to net absorption [1–5]. The transition from fetal to neonatal circulatory patterns requires resolution of the pulmonary hypertension present in the fetus, normally shunting blood flow through the lower resistance ductus arteriosus in the fetal state, so as to direct cardiac output to the pulmonary vasculature for participation in gas exchange. This change is achieved by the opening of alveoli, decreasing airway resistance, and providing radial support for pulmonary vessels, functional closure of the ductus arteriosus, and increased oxygen tension in the lung, which reverses pulmonary vasoconstriction mediated by hypoxia [6,7]. Pulmonary tree vasodilators (prostacyclin and nitric oxide [NO]) and vasoconstrictors (endothelin-1 [ET-1] and leukotrienes) play apparently well-coordinated but as yet not fully elucidated roles. In the normal newborn, this change is smooth and rapid. These critical events are undermined by factors like inadequate lung development, surfactant deficiency (primary or secondary), viral or bacterial infection, placental abnormalities, in utero hypoxia, and meconium aspiration. Spontaneous breathing should begin in the neonate within 1 minute of birth; many foals attempt to breathe as their thorax clears the pelvic canal
Medicated Manuka honey in conservative management of exomphalos major.

Purpose The aim of this study was to assess the effectiveness of Manuka honey ointment and dressings in the conservative management of exomphalos major (EM).
Mirror, mirror, on the wall . . .

Has this happened to you? In the darkness, on a lonely country road, your headlights play across a pair of bright green, almost iridescent, spots of light; they seem to float eerily across the road without support. These furtive spots seem to move and blink, clearly alive. Eyeshine. It is all you see of the creature, as the rest of the body seems to disappear into the darkness that surrounds it. But, what exactly is eyeshine, and why did it evolve? The tapetum lucidum (Latin, carpet shining) is a reflective structure found in the eyes of many diverse creatures and represents convergent ocular evolution solely for maximising photon capture. Surprisingly, the techniques for the production of these reflective mechanisms are variable, and much like the crystalline lens, seem to be drawn from whatever materials the evolutionary process found at hand. Guanine crystals, for example, provide biological reflection and support camouflage by making a fish glisten and gleam, and hence appear invisible or at least present confusing reflections to a predator. Although we can never know for sure, this coating probably appeared very …
Te and Cd nuclear-magnetic-resonance study of local structure and bonding in Cd 1 − x Zn x Te

Magic-angle sample-spinning NMR spectra of $^{111}\mathrm{Cd}$ and $^{125}\mathrm{Te}$ in ${\mathrm{Cd}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Zn}}_{\mathrm{x}}$Te semiconductor alloys have been recorded for 0\ensuremath{\le}x\ensuremath{\le}1. The $^{111}\mathrm{Cd}$ NMR spectra exhibit a single line whose chemical shift and linewidth depend on x. The linear dependence of the $^{111}\mathrm{Cd}$ chemical shift on x is assumed to be the result of charge transfer, while the linewidth dependence is shown to be the result of a random distribution of Zn atoms which are next-nearest neighbors to Cd. The $^{125}\mathrm{Te}$ spectra exhibit multiple lines, their number and chemical shift depending on x. The different chemical shifts of the Te lines are assigned to the five different cation configurations---${\mathrm{Cd}}_{\mathrm{n}}$${\mathrm{Zn}}_{4\mathrm{\ensuremath{-}}\mathrm{n}}$, n=0,...,4---around the Te. The intensities of the experimental Te lines are compared to those in spectral simulations obtained by assuming a random distribution of the cations. The comparison reveals small deviations from a random distribution of the cations. This clustering phenomenon and the effect of the bond-length changes with x on the $^{125}\mathrm{Te}$ chemical shift are discussed.
Electrochemical cells for in situ EXAFS

Abstract The structural information obtainable from EXAFS can make an important contribution to traditional electrochemical studies of wet electrode surfaces. It is critical that the technique be made sufficiently near-surface sensitive while maintaining a properly controlled electrochemical environment. We report our experience with several electrochemical cells with both X-ray fluorescence and electron detection that were used specifically for the study of iron passivation in buffered borate. The cells may easily be applied to other materials and even corrosive environments.
Effect of hyperthyroidism on intestinal absorption of calcium in the rat.

Summary and conclusionsIntestinal active transport of calcium was studied by an in vitro gut sac technic in rats with induced hyperthyroidism. An excess of thyroid hormone resulted in a prompt and persistent decrease in calcium transport, and also in a decrease of trabecular bone. The mechanism of this action of thyroid hormone and its physiologic significance is yet to be determined. It is suggested that decreased calcium absorption may be a significant factor in the negative calcium balance and bone changes found in some hyper thyroid patients.
Rapid protein-ligand costructures using chemical shift perturbations.

Structure-based drug discovery requires the iterative determination of protein−ligand costructures in order to improve the binding affinity and selectivity of potential drug candidates. In general, X-ray and NMR structure determination methods are time consuming and are typically the limiting factor in the drug discovery process. The application of molecular docking simulations to filter and evaluate drug candidates has become a common method to improve the throughput and efficiency of structure-based drug design. Unfortunately, molecular docking methods suffer from common problems that include ambiguous ligand conformers or failure to predict the correct docked structure. A rapid approach to determine accurate protein−ligand costructures is described based on NMR chemical shift perturbation (CSP) data routinely obtained using 2D 1H−15N HSQC spectra in high-throughput ligand affinity screens. The CSP data is used to both guide and filter AutoDock calculations using our AutoDockFilter program. This method ...
The surgeon's work in transition: should surgeons spend more time outside the hospital?

Libby Zion was an 18-year-old college student who died in a New York City emergency room in 1984. Her father, a newspaper columnist and former federal prosecutor, sued the hospital and campaigned against long working hours for residents. As a result, New York State passed the “Libby Zion Law” in 1989, limiting work hours for house officers [1]. Ever since then, events have moved steadily, albeit in fits and starts, toward a conclusion that now seems to have been inevitable. The national 80-hour workweek mandated for house officers by the Accreditation Council for Graduate Medical Education has begun, and the disruption of traditional work schedules will be dealt with more or less effectively in medical graduate training programs around the country [2]. We do not know what effect these changes will have on the profession of surgery, but most of us strongly suspect that it will not be good. At the very least, surgeons of the future are likely to have a work ethic that is different from the one we acquired during and after our training. In fact, a shift in attitude toward work seems to be well underway already. Applications to general surgical training programs have been in progressive decline over the last few years. Much of the decline seems to be related to changes in professional expectations of medical students. These students want controlled working hours and more dedicated time for family and leisure activities [3]. Perhaps the mandatory reduction in work schedule for residents will reawaken interest in surgical training. In any case, it appears that the era of the “24/7” availability of surgeons and 16 to 18 hour workdays (only 4 to 8 hours on weekend days with an occasional weekend off) may be ending and slowly fading into oblivion. Assuming that this scenario of surgery’s future is accurate, does it contain lessons for those of us still caught up in the old paradigm? Is there something to be said for or, perhaps, something to be gained from cardiothoracic surgeons joining the trend by adopting a more friendly family or personal lifestyle attitude toward the distribution of our waking hours? The question of more time for surgeons outside the hospital was debated at The Southern Thoracic Surgical Association Annual Meeting in November 2002. The topic of the debate was “The surgeon’s work in transition: surgeons should cut back on time in the hospital to spend more time with family and personal interests.” Ross Ungerleider argued the affirmative position, and Joseph Coselli argued the negative position. Their positions are presented with the assistance of co-authors in the following essays.
Rapid solution of integral equations of scattering theory in two dimensions

Abstract The present paper describes an algorithm for rapid solution of boundary value problems for the Helmholtz equation in two dimensions based on iteratively solving integral equations of scattering theory. CPU time requirements of previously published algorithms of this type are of the order n 2 , where n is the number of nodes in the discretization of the boundary of the scatterer. The CPU time requirements of the algorithm of the present paper are n 4 3 , and can be further reduced, making it considerably more practical for large scale problems.
Signal transduction pathways controlling multicellular development in Dictyostelium

The importance of signal transduction pathways in regulating developmental processes in a number of organisms has become evident in recent years. This is exceptionally clear for Dictyostelium, which uses soluble factors to regulate morphogenesis and cellular differentiation. It is now known that many of these processes are controlled by signal transduction pathways mediated by cyclic AMP through cell surface receptors coupled to G proteins, and that others are mediated by the morphogen DIF.
Thermodynamic properties, low-temperature heat-capacity anomalies, and single-crystal X-ray refinement of hydronium jarosite, (H 3 O)Fe 3 (SO 4 ) 2 (OH) 6

Crystals of hydronium jarosite were synthesized by hydrothermal treatment of Fe(III)–SO4 solutions. Single-crystal XRD refinement with R1=0.0232 for the unique observed reflections (|Fo| > 4σF) and wR2=0.0451 for all data gave a=7.3559(8) A, c=17.019(3) A, Vo=160.11(4) cm3, and fractional positions for all atoms except the H in the H3O groups. The chemical composition of this sample is described by the formula (H3O)0.91Fe2.91(SO4)2[(OH)5.64(H2O)0.18]. The enthalpy of formation (ΔHo f ) is −3694.5 ± 4.6 kJ mol−1, calculated from acid (5.0 N HCl) solution calorimetry data for hydronium jarosite, γ-FeOOH, MgO, H2O, and α-MgSO4. The entropy at standard temperature and pressure (So) is 438.9±0.7 J mol−1 K−1, calculated from adiabatic and semi-adiabatic calorimetry data. The heat capacity (C p ) data between 273 and 400 K were fitted to a Maier-Kelley polynomial C p (T in K)=280.6 + 0.6149T–3199700T−2. The Gibbs free energy of formation is −3162.2 ± 4.6 kJ mol−1. Speciation and activity calculations for Fe(III)–SO4 solutions show that these new thermodynamic data reproduce the results of solubility experiments with hydronium jarosite. A spin-glass freezing transition was manifested as a broad anomaly in the C p data, and as a broad maximum in the zero-field-cooled magnetic susceptibility data at 16.5 K. Another anomaly in C p , below 0.7 K, has been tentatively attributed to spin cluster tunneling. A set of thermodynamic values for an ideal composition end member (H3O)Fe3(SO4)2(OH)6 was estimated: ΔGo f = −3226.4 ± 4.6 kJ mol−1, ΔHo f =−3770.2 ± 4.6 kJ mol−1, So=448.2 ± 0.7 J mol−1 K−1, C p (T in K)=287.2 + 0.6281T–3286000T−2 (between 273 and 400 K).
Every (p, p-2) graph is contained in its complement†

The following is proved: If G is graph of order p (≥2) and size p-2, then there exists an isomorphic embedding of G into its complement.
Genetic and epigenetic mechanisms of gene regulation during lens development

Recent studies demonstrated a number of links between chromatin structure, gene expression, extracellular signaling and cellular differentiation during lens development. Lens progenitor cells originate from a pool of common progenitor cells, the pre-placodal region (PPR) which is formed due to a complex exchange of extracellular signals between the neural plate, naive ectoderm and mesendoderm. A specific commitment to the lens program over alternate choices such as the formation of olfactory epithelium or the anterior pituitary is manifested by the formation of a thickened surface ectoderm, the lens placode. Mouse lens progenitor cells are characterized by the expression of a complement of lens lineage-specific transcription factors including Pax6, Six3 and Sox2, controlled by FGF and BMP signaling, followed later by c-Maf, Mab21like1, Prox1 and FoxE3. Proliferation of lens progenitors together with their morphogenetic movements results in the formation of the lens vesicle. This transient structure, comprised of lens precursor cells, is polarized with its anterior cells retaining their epithelial morphology and proliferative capacity, whereas the posterior lens precursor cells initiate terminal differentiation forming the primary lens fibers. Lens differentiation is marked by expression and accumulation of crystallins and other structural proteins. The transcriptional control of crystallin genes is characterized by the reiterative use of transcription factors required for the establishment of lens precursors in combination with more ubiquitously expressed factors (e.g. AP-1, AP-2α, CREB and USF) and recruitment of histone acetyltransferases (HATs) CBP and p300, and chromatin remodeling complexes SWI/SNF and ISWI. These studies have poised the study of lens development at the forefront of efforts to understand the connections between development, cell signaling, gene transcription and chromatin remodeling.
Learning from Barcelona: Discourse, Power and Praxis in the Sustainable City

In the 2004 Forum for World Cultures, Barcelona politicians and intellectuals situated sustainability as a key issue for global and local debate. This event also distilled historical experiences of place, contact and conflict that have shaped Barcelona as a global city, while subsequent discussions illuminate the complexities of the creation of an urban culture of sustainability as contemporary urban social practice. Reading sustainability as myth and practice in both spatial and temporal contexts reveals the extent to which ecological commitments combine changes in urban policy, rhetorical statements, positioning within more general competitions for urban branding and citizen responses. Drawing on archival and cultural analysis as well as longterm ethnography, this paper examines Barcelona's search for social ecological policy and the complications of multiple visions and practices of sustainable development.
Efficient parallel algorithms for 2-dimensional ising spin models

In this paper, we design and implement a variety of parallel algorithms for both sweep spin selection and random spin selection. We analyze our parallel algorithms on LogP, a portable and general parallel machine model. We then obtain rigorous theoretical runtime results on LogP for all the parallel algorithms. Moreover, a guiding equation is derived for choosing data layouts (blocked vs. stripped) for sweep spin selection. In regards to random spin selection, we are able to develop parallel algorithms with efficient communication schemes. We introduce two novel schemes, namely the FML scheme and the ?-scheme. We analyze randomness of our schemes using statistical methods and provided comparisons between the different schemes.
Influence of level and source of crude fiber in calf starters on weight and feed consumption.

Summary Thirty-five Holstein and Jersey calves were fed starters containing five, nine, or 13% crude fiber, with the fiber of the higher levels coming from either corn cobs and shucks or alfalfa meal. There were no important differences among the calves owing to level or source of crude fiber, in weight gain, starter consumption, or hay consumption, at either eight or 16 weeks (P = 0.05). Highly significant simple correlation and regression coefficients were observed at 16 weeks of age, between starter consumption and gain (r = 0.86) (b = 0.37-lb.) and between starter consumption and hay consumption (r = −0.55) (b = −0.59-lb.). Highly significant partial correlation and regression coefficients were observed between starter consumption and gain and between hay consumption and gain.
Drug therapy in patients with Parkinson’s disease

Parkinson`s disease (PD) is a progressive, disabling neurodegenerative disorder with onset of motor and non-motor features. Both reduce quality of life of PD patients and cause caregiver burden. This review aims to provide a survey of possible therapeutic options for treatment of motor and non motor symptoms of PD and to discuss their relation to each other. MAO-B-Inhibitors, NMDA antagonists, dopamine agonists and levodopa with its various application modes mainly improve the dopamine associated motor symptoms in PD. This armentarium of PD drugs only partially influences the onset and occurrence of non motor symptoms. These PD features predominantly result from non dopaminergic neurodegeneration. Autonomic features, such as seborrhea, hyperhidrosis, orthostatic syndrome, salivation, bladder dysfunction, gastrointestinal disturbances, and neuropsychiatric symptoms, such as depression, sleep disorders, psychosis, cognitive dysfunction with impaired execution and impulse control may appear. Drug therapy of these non motor symptoms complicates long-term PD drug therapy due to possible occurrence of drug interactions, - side effects, and altered pharmacokinetic behaviour of applied compounds. Dopamine substituting compounds themselves may contribute to onset of these non motor symptoms. This complicates the differentiation from the disease process itself and influences therapeutic options, which are often limited because of additional morbidity with necessary concomitant drug therapy.
Receiver comparisons on an OFDM design for Doppler spread channels

Underwater acoustic channels induce large Doppler drifts that render intercarrier interference (ICI) for OFDM transmissions. Assuming that after proper Doppler compensation the residual ICI is limited to only direct neighbors, we propose an OFDM signal design that decouples channel estimation and data demodulation. We investigate eight receivers that are categorized into three groups: (i) three receivers that ignore the residual ICI, (ii) three receivers that are based on a basis expansion model (BEM) and pursue channel estimation independently along each basis, and (iii) two receivers that are based on discrete-path modeling. The receiver performance is compared based on data from the SPACE experiment conducted off the coast of Martha's Vineyard, Massachusetts, October 2008. The receiver based on the discrete-path modeling and a basis pursuit algorithm achieves the best performance while the receiver based on BEM and least-squares channel estimation performs the worst. The performance differences among different receivers drastically increase as the channel's Doppler spread and the signal constellation size increase. Interestingly, the BEM based receivers are often inferior to the ICI-ignorant counterparts, implying that the ability of ICI compensation could be limited by the estimation accuracy of the much increased number of model parameters.
Cerebral Oxygenation During Exercise in Cardiac Patients

Background Until recently, compensatory mechanisms have been believed to regulate adequately cerebral blood flow in humans. However, this has been called into question by a series of new investigations suggesting that patients with left ventricular dysfunction suffer from cerebral hypoperfusion. We compared cerebral oxygenation during incremental exercise between patients with valvular heart disease and normal subjects. Methods Thirty-three patients with valvular disease and 33 normal subjects performed a symptom-limited incremental exercise test using a cycle ergometer. Oxyhemoglobin at the forehead was continuously monitored during exercise using near-infrared spectroscopy. Respiratory gas measurements were performed on a breath-by-breath basis. Results The increase in oxyhemoglobin during exercise was significantly lower in the patients with valvular disease than in normal subjects. The change in oxyhemoglobin during exercise (ΔO 2 Hb) at the forehead was negatively correlated with the slope of the increase in minute ventilation to the increase in carbon dioxide output (Δ e /Δ co 2 ), and positively correlated with the peak oxygen uptake ( o 2 ), gas exchange threshold (GET), and slope of the increase in o 2 to the increase in the work rate (Δ o 2 /ΔWR). Among the patients with valvular disease, 15 patients showed a decrease in oxyhemoglobin at the forehead during exercise. When compared with the patients with increased oxyhemoglobin, those with decreased levels exhibited a higher Δ e /Δ co 2 and a lower peak o 2 , GET, and Δ o 2 /ΔWR. Conclusions The present findings strongly suggest that cerebral oxygenation during exercise is dependent on the cardiovascular and pulmonary systems. The study also indicated the presence of cerebral hypoperfusion during exercise in cardiac patients whose cardiac output fails to increase normally.
Knowledge objects and mental models

This paper describes knowledge components that are thought to be appropriate and sufficient to precisely describe certain types of cognitive subject matter content (knowledge). It also describes knowledge structures that show the relationships among these knowledge components and among other knowledge objects. It suggests that a knowledge structure is a form of schema such as those that learners use to represent knowledge in memory. A mental model is a schema plus cognitive processes for manipulating and modifying the knowledge stored in a schema. We suggested processes that enable learners to manipulate the knowledge components of conceptual network knowledge structures for purposes of classification, generalization, and concept elaboration. We further suggested processes that enable learners to manipulate the knowledge components of process knowledge structures (PEAnets) for purposes of explanation, prediction, and troubleshooting. The hypothesis of this paper is that knowledge components and knowledge structures, such as those described in this paper, could serve as meta mental models that would enable learners to more easily acquire conceptual and causal networks and their associated processes. The resulting specific mental models would facilitate their ability to solve problems of conceptualization and interpretation.
Analysis of the Virulence Characteristics of Bacteria Isolated from Bottled, Water Cooler, and Tap Water

A study was conducted to determine the numbers and types of bacteria found in three water sources—bottled water, water cooler water, and tap water—and to determine their virulence characteristics. A wide variety of water types were collected and each was analysed for Heterotrophic Plate Count (HPC) bacteria, Pseudomonas aeruginosa , and total coliforms. For each isolate, virulence characteristics were determined by enzyme analysis (10 associated with virulence), antibiotic susceptibility testing (natural and semi-synthetic antibiotics), acid lability (survival at pH 3-5), and cytotoxicity testing (HEp-2 cells). Results showed that all water sources had a normal bacterial content. Only 2 per cent of bottled water sources had P. aeruginosa . Total coliforms were isolated only from bottled water that used mixed (water alternating with milk) filling lines. Environmental bacteria did not produce significant enzymes associated with virulence, were not acid resistant, were susceptible to semi-synthetic antibiotics, and did not produce appreciable cytotoxicity. These natural aqueous bacteria were adopted to a water environment, did not grow well at conditions analogous to the human host, and did not have the characteristics associated with virulence. Future drinking water revisions and changes to the treatment processes should be directed towards the elimination of specific pathogens and to the prevention of exogenous sources of contamination rather than the elimination of natural water microbial populations. Keywords: virulence factors, drinking water, health risk, heterotrophic bacteria, water regulations.