cssi/SciSciGPT-SciSciNet huggingface dataset:
Reference dose of the United States Environmental Protection Agency.

Empirical data demonstrate that, as the administered dose of a chemical increases, the toxic responses generally increase. These increases occur in both the severity of the response (eg, with new and more severe effects being observed) and the intensity of the response (ie, magnification of an effect of given severity), and the percentage of the population affected increases as well. Such dose-response relationships are well founded in the theory and practice of toxicology and pharmacology. Dose-response assessment follows hazard identification in the risk assessment process as defined by the United States National Academy of Sciences (NAS) (1). Dose-response assessment involves the quantitative evaluation of toxicity data to determine the likely incidence of the associated effects on humans. The information available for dose-response assessment ranges from well-conducted and controlled studies of human exposure and epidemiologie studies with large numbers of subjects, well-characterized exposures and supportive studies on several animal species to a lack of human and animal toxicity data with only structure-activity relationships to guide the evaluation. In any case, scientists should consider all pertinent studies in this process even a single human case study can provide useful information. However, only data of sufficient quality, as judged by experts such as the EPA Reference Dose Reference Concentration Work Group, should be used in the dose-response assessment of a chemical. With at least a moderate amount of toxicity data, one goal has been to determine a level of daily exposure that is likely to be without an appreciable risk of deleterious effects during a lifetime. The World
Critical-region vapor-liquid equilibrium of the CH sub 4 -CO sub 2 -H sub 2 S system

The Oak Ridge National Laboratory (ORNL) has proposed a process for purifying substitute natural gas streams by absorption-fractionation in liquid CO{sub 2}. In order to further the development of this process, additional vapor-liquid equilibrium data was needed to supplement the literature data. The primary objective of the study presented here was to design, construct, and test an apparatus at the Oak Ridge National Laboratory to measure vapor-liquid equilibrium properties of binary and multicomponent systems which are of interest to this process. The CH{sub 4}-CO{sub 2}-H{sub 2}S system and the associated binary systems have been studied in this work between 270.0 K and 288.2 K. Binary interaction parameters have been determined for each of the binary systems and used to calculate the equilibrium phase properties of the binary and ternary systems. A comparison of these calculations with the experimental results is presented. 37 refs.
Relations of left ventricular geometry and function to prognosis in hypertension.

The heart plays a central role in systemic hypertension, since it both generates the increased force needed to sustain elevated arterial blood pressure and suffers the morbid consequences thereof. The importance of left ventricular (LV) hypertrophy as a cardinal manifestation of hypertensive target organ damage was first suspected based on the ability of ECG LV hypertrophy to predict morbidity and mortality in patients with hypertension,1–3 in the general population,4–5 and in catheterized patients with or without coronary artery obstruction.6 However, it was uncertain whether these patterns derived their significance from cardiac hypertrophy or from ECG manifestations of myocardial ischemia. This uncertainty has been resolved by the demonstration that increased LV mass is a potent predictor of cardiovascular morbidity and mortality, independent of age, gender, blood pressure or other risk factors.7–19 It is the purpose of this chapter to review available evidence concerning: 1) the relation of LV hypertrophy to prognosis; 2) whether additional consideration of LV geometric patterns further aids risk stratification; 3) the relation between LV myocardial function and prognosis; 4) potential mechanisms of observed relations between LV muscle mass and function on, the one hand, and morbid events due to vascular thrombosis, on the other; and 5) available evidence concerning the possible prognostic benefit of LV hypertrophy regression.
A Modular Strategy for Recovery and Management of Biomass Yields in Large Marine Ecosystems

During the decade since the 1992 United Nations Conference on Environment and Development, considerable movement has been made by international organizations engaged in ocean affairs to move nations toward adopting ecosystem-based assessment and management strategies. The 191 nations, including 82 heads of state, participating in the 2002 World Summit on Sustainable Development in Johannesburg agreed to a plan of implementation (POI) that encourages nations to apply the ecosystem approach to marine resource assessment and management practices by 2010, and maintain or restore fish stocks to levels that can produce maximum sustainable yield levels by 2015. To achieve these targets will require an improved understanding and assessment of the effects of physical, biological and human forcing causing changes in biomass yields of large marine ecosystems (LMEs). An international financial mechanism, the Global Environment Facility (GEF), is assisting developing countries in meeting the Summit targets by supporting LME assessment and management projects. Of the 29 LMEs for which published case study information is available for analyses of principal forces driving changes in biomass yields, fishing effort was the primary forcing mechanism in 14 LMEs; climate forcing was the principal factor in 13 LMEs, eutrophication in one case and the data were inconclusive in another. Fishing effort was a secondary driver of change in biomass yields in the LMEs driven by climate forcing. Mitigating actions for reducing fishing effort to promote recovery of lost biomass yield is proving successful in one case study. Actions for improving forecasts of oceanographic conditions affecting fish stocks are underway in four GEF supported LME projects (e.g. Humboldt Current, Canary Current, Guinea Current, Benguela Current); measures to assess and manage excessive fishing effort are planned for 8 LME projects, eutrophication reduction and control in another, and 6 LMEs with relatively stable decadal biomass yields appear suitable for mandating precautionary total allowable catch (TAC) levels. The GEF-LME projects include countries that contributed to 45% of global marine biomass yields in 1999.
The choice not to undergo genetic testing for Huntington disease: Results from the PHAROS study.

Rates of genetic testing in Huntington disease (HD) are lower than was predicted before direct DNA testing became available. Clinicians often do not have in-depth conversations with people at risk who chose not to test. We queried 733 research subjects who chose not to learn their HD gene status when enrolling in the Prospective Huntington At-Risk Observational Study, carried out between 1999 and 2008. Lack of an effective cure or treatment (66% of subjects) and inability to undo knowledge (66%) were the major reasons cited for choosing not to undergo HD DNA testing. Most subjects were not concerned about the length or burden of the testing process (61% and 59%, respectively). Subjects were optimistic that a treatment to improve symptoms or postpone onset would be developed within the next 10 years (56% and 53%, respectively), but they had less certainty about the prospects to prevent HD onset (36%). This is the first large, systematic study of why people at risk for HD choose not to undergo genetic testing. Attitudes about how people at risk for HD approach this life-altering choice should be reassessed as new treatments develop, and as clinical trials now require genetic testing at entry.
Assessment of the Readability, Availability, and Quality of Online Patient Education Materials Regarding Uveitis Medications.

Purpose: To assess the availability, quality, and readability of online patient education materials regarding uveitis medications.Methods: The top 10 Google search results for 10 commonly prescribe...
Cannabis and work: need for more research

Cannabis sativa is one of the oldest and most widely used plants in the world with a variety of industrial, medical, and nonmedical applications. Despite its long history, cannabis-derived products remain a source of controversy across the fields of medicine, law, and occupational safety and health. More favorable public attitudes about cannabis in the US have resulted in greater access to cannabis through legalization by states, leading to more consumption by workers. As more states adopt cannabis access laws, and as more workers choose to consume cannabis products, the implications for existing workplace policies, programs, and practices become more salient. Past workplace practices were grounded in a time when cannabis consumption was always viewed as problematic, considered a moral failing, and was universally illegal. Shifting cultural views and the changing legal status of cannabis indicate a need for research into the implications and challenges relating to cannabis and work. This commentary suggests research needs in the following areas: (a) data about industries and occupations where cannabis consumption among workers is most prevalent; (b) adverse health consequences of cannabis consumption among workers; (c) workplace supported recovery programs; (d) hazards to workers in the emerging cannabis industry; (e) relationship between cannabis consumption and occupational injuries; (f) ways to assess performance deficits and impairment from cannabis consumption; (g) consumption of synthetic cannabinoids to evade detection by drug testing; (h) cannabis consumption and its effect on occupational driving; and (i) ways to craft workplace policies and practices that take into consideration conflicting state and federal laws pertaining to cannabis.
Ridesharing Regulation in the USA

After initial resistance by some regulators and incumbent taxi drivers, ridesharing is now legal throughout the USA. Indeed, taxi markets were one of the last transportation markets subject to significant regulation, and deregulation followed the model established in previous decades, when the USA deregulated railroads, airlines, telecommunications, and many other transportation and utility services. Some important controversies continue, such as congestion, universal service, and safety regulation; the status of drivers; and emerging issues of data privacy. But the rapid transition has resulted in more open and competitive markets across the USA.
Laparoscopic Inguinal Hernia Repair: Undervalued by the Relative Value Unit System.

Work relative value units (wRVUs) serve as a proxy of surgeon’s effort, technical skill, and time to determine reimbursement. The aim of this study is to determine how accurately wRVUs reflect the ...
Stability Balls and Student on-Task Behavior

Stability balls have become a common option for alternative seating in classrooms. While the social validity of stability ball classroom seating remains high among students and teachers, findings on the effectiveness of this alternative seating method are mixed. This is particularly true when the intent of the intervention is to increase student on-task behavior. This study examined the effects of stability ball seating on students’ on-task behavior in a general education setting, using a within-subjects repeated measures design. Researchers observed twenty-four third-grade students in a public-school classroom across three conditions: all chairs, all balls, or choice. Across observation days, the study controlled for time of day, teacher, and classroom environment. Results indicate students are on-task less frequently when sitting on a stability ball. Student reports on social validity replicated prior findings; students found the stability ball to be desirable and easy to use.
The Efficacy of Term Structure Estimation Techniques: A Monte Carlo Study

Business. I t is well-recognized that the term structure of defaultfree interest rates is not directly observable in a market where government obligations of various maturities bear coupons at different rates, and where ordinary income and capital gains are subject to unknown and varying effective tax rates. (See, for example, Jordan [1984], Livingston [1979], McCulloch [1975], Robicheck and Niebuhr [1970], Ronn [I 9871, Schaefer [1982], and Torous [1985].) At the same time, accurate knowledge of the term structure of spot rates and the underlying term structure of forward rates is essential for financial research and practice. This information cannot be obtained from the yield curve of Treasury strips, because those obligations are traded in a separate and distinct market. The strips market is dominated by a unique clientele of U.S. taxexempt institutions and Japanese investors who have a tax incentive to hold long-term principal (versus coupon) strips. There are unknown differences in effective tax rates between the two markets, and a drfference in liquidity in favor of the wider market for standard coupon bonds. The term structure underlying the coupon bond market must therefore be estimated from bonds traded in that market. Such estimates are required for the management of fixed-income security portfolios and for pricing interest rate-contingent claims such as fixed-income securities, options, and futures (see Ho and Lee [I9861 and Kishimot
Disparities in potential years of life lost due to intimate partner violence: Data from 16 states for 2006-2015.

Background Intimate partner violence can lead to deaths of one or both partners and others (i.e., corollary victims). Prior studies do not enumerate the societal cost of intimate partner violence-related fatalities, exclude corollary victims from most analyses, and do not describe groups who bear the highest societal costs from intimate partner violence. Objective We examine racial/ethnic and gender-based disparities in potential years of life lost (PYLL) among intimate partners and corollary victims of intimate partner violence-related mortality. Methods We used 16 US states’ 2006–2015 National Violent Death Reporting System data to estimate PYLL among intimate partners (n = 6,282) and corollary victims (n = 1,634) by victims’ race/ethnicity and sex. We describe fatalities by sex, race/ethnicity, age, and victim-suspect relationships and used hierarchical linear models to examine PYLL per death differences by victims’ sex and race/ethnicity. Results Nearly 290,000 years of potential life were lost by partner and corollary victims as a result of IPV in 16 states during the decade of study. Most partner victims were female (59%); most corollary victims were male (76%). Female intimate partners died 5.1 years earlier (95% CI: 4.4., 5.9) than males, and female corollary victims died 3.6 years (1.9, 5.5) earlier than males. Racial/ethnic minorities died nine or more years earlier than their White counterparts. White males had the lowest PYLL per death of all sex/race groups. Implications Intimate partner violence-related fatalities exact a high societal cost, and the burden of that cost is disproportionately high among racial/ethnic minorities. Future interventions targeting specific sex and race/ethnic groups might help reduce disparities in intimate partner violence burden.
Prediction of a ferromagnetic ground state for NaCl-type FeN

Ab initio results for structural and electronic properties of NaCl-type FeN are presented. Calculations are performed within a plane-wave and ultrasoft pseudopotential framework. Competition among paramagnetic, ferromagnetic and some possible antiferromagnetic phases is examined. We find the ferromagnetic phase stable overall as observed. Stabilization over the unpolarized phase is obtained by splitting one flat ${t}_{2g}$-type band crossing the Fermi energy. Comparison with CrN reveals that the magnetic ordering of CrN, which consists of double-ferromagnetic sheets compensating along the [110] direction of the cubic cell and stabilized by the distortion of the squared symmetry on (100) plane, is not effective for FeN. The different behavior of FeN and CrN can be traced back to the smaller ionicity and magnetization of the former.
Artificial neural network models for airport capacity prediction

Abstract This paper proposes artificial neural network models to predict the arrival/departure capacity of airports. Multilayer perceptron (MLP), recurrent neural networks (RNN), and long short-term memory (LSTM) models have been trained using capacity and meteorological data from Hartsfield–Jackson Atlanta International Airport (ATL) from 2013 to 2017. The models’ predictive performances were validated against the observed capacity of ATL in 2018. The qualitative and quantitative analysis of the trained models confirmed that the artificial neural networks approach is effective in predicting airport capacity. In addition, the transferability of the models for Boston Logan International Airport (BOS) is examined. Capacity prediction performance for BOS measures the transferability of the models trained with the ATL data. MLP showed good transferability without taking any other measures, and RNN and LSTM were able to predict the BOS capacity well after fine-tuning.
Case–control study of high‐speed exercise history of Thoroughbred and Quarter Horse racehorses that died related to a complete scapular fracture

Summary Reasons for performing study: Identification of exercise history patterns that are related to catastrophic scapular fracture will facilitate prevention of racehorse fatalities. Objectives: To determine if exercise patterns are associated with scapular fracture in Thoroughbred (TB) and Quarter Horse (QH) racehorses. Methods: High-speed exercise histories for 65 TB and 26 QH racehorses that had a complete scapular fracture (cases) and 2 matched control racehorses were retrospectively studied. Exercise variables were created from lifetime race and official timed workout reports. Associations between exercise variables and scapular fracture were investigated using conditional logistic regression. Results: Thoroughbreds with a scapular fracture had a greater number of workouts, events (combined works and races), and mean event distances than QHs with a scapular fracture. Quarter Horses worked less frequently and accumulated distance at a lower rate than TBs. Breed differences were not found for career race number or length, time between races or lay-up variables for horses with ≥1 lay-up. For both breeds, cases had fewer events, lower recent accumulated distance and fewer active days in training than controls; however, a subset of TB cases with >10 events since lay-up had a longer active career than controls. For QHs that had a lay-up, total and mean lay-up times were greater for cases than controls. Multivariable models revealed that odds ratios (OR) of scapular fracture were greater for TBs that had not yet raced (OR = 23.19; 95% confidence interval (CI) 3.03–177.38) and lower for QHs with more events (OR = 0.71; 95% CI 0.54–0.94). Conclusions and clinical relevance: Racehorses that are in early high-speed training but behind that of their training cohort should be examined for signs of scapular stress remodelling. Quarter Horses that had a prolonged lay-up and TBs that have endured high-speed training for a longer duration than that of their training cohort also were at greater risk.
Do African American Students' Perceptions Of Their Needs Have Implications For Retention?:

African American student retention on predominantly White campuses continues to be one of the greatest challenges for many colleges and universities. In addition to the impact of student attrition on the economic well-being of the university, the image of the university is at risk when African American students' attrition rates far exceed those of White students. Researchers, when studying factors related to retention, found that high GPA and test scores predict academic performance differently for African American students than for White students (Farver, Sedlacek, & Brooks, 1975; Lunneborg & Lunneborg, 1986). Even when academic preparation was considered, disparity still resulted. Steele (1992) observed that
Distributed management of replicated and partitioned files under DRAGON SLAYER

The authors describe the file management system of DRAGON SLAYER, a distributed operating system which provides transparent resource sharing in a heterogeneous local area network with completely decentralized control. Users are able to use any of the system files for which they have authorization, without regard to the individual characteristics of the computers on which the files reside or the physical locations of the users and files. In addition, files can be dynamically fragmented, and the fragments can be replicated and relocated dynamically. Copies are kept mutually consistent while all file operations work either transparently on the whole file or on specific fragments. The DRAGON SLAYER resource management supporting these file system operations is presented. Beyond the obvious advantages of file access reliability and flexibility, the authors present simulation results proving the superior performance of this file system as compared with conventional distributed file systems with non-fragmented files. >
Variation in Computed Tomography Imaging for Pediatric Injury-Related Emergency Visits

Objective To assess variation in the use of computed tomography (CT) for pediatric injury-related emergency department (ED) visits. Study design This was a retrospective cohort study of visits to 14 network-affiliated EDs from November 2010 through February 2013. Visits were identified by International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis codes. Primary outcome was CT use. We used descriptive statistics and performed multivariable logistic regression to evaluate the association of patient and ED covariates on any and body region–specific CT use. Results Of the 80 868 injury-related visits, 11.4% included CT, and 28.4% of those involved more than 1 CT. Across EDs, CT use ranged from 7.6% to 25.5% of visits and did not correlate with institutional Injury Severity Score ( P = .33) or admission/transfer rates ( P = .07). In multivariable analysis of nonpediatric EDs, trauma centers and nonacademic EDs were associated with CT use. Higher pediatric volume was associated with any CT use; however, there was an inverse relationship between volume and nonhead CT use. When the pediatric ED was included in multivariable modeling, the effect of level 1-3 trauma center designation remained, and the pediatric level 1 trauma center was less likely to use most body region–specific CTs. Conclusion There is wide variation in CT imaging for pediatric injury-related visits not attributable solely to case mix. Future work to optimize CT utilization should focus on additional factors contributing to imaging practices and interventions.
Technical issues: area control considerations in the WAPP and SAPP areas

With a population of 13.4% of the world but only consumes 3 % of world energy, Africa is desperately needed cheap and clean energy for economic development and modernization. The Survey of Energy Resources conducted by the World Energy Council (WEC) in 2004 shows that Africa has more than enough to satisfy all its energy requirements. However, the resources are not evenly distributed within the continent. It is important to have cross-border interconnection of electricity grids and gas pipelines networks and the joint development of new electrical generation projects to make the energy accessible to the general public. However, interconnecting AC network will increase the complexity of the system that may increase the system reliability, security, and stability problems due to the interactions of equipment and control actions. This paper uses the development of West Africa power pool (WAPP) and Southern Africa power pool (SAPP) to discuss area control considerations in this cross countries interconnection utility grid.
Accelerated tooth movement: Do we need a new systematic review?

Current systematic reviews are important for health care providers in supporting their evidence-based practice decisions. Equally important is the ability to determine when a new systematic review is needed in view of the rapid publication output. The current best evidence from a 2013 systematic review suggests that certain treatments may accelerate orthodontic tooth movement. Our aim was to determine if an updated systematic review is needed on this topic by applying the modified Ottawa method. A systematic search of Pubmed, Embase, CENTRAL, and Web of Science databases, identical to the previous systematic review, was executed. Two authors performed screening for inclusion/exclusion of studies and selected full-text articles were reviewed. Qualitative and quantitative criteria were applied to assess studies describing the following types of interventions to accelerate tooth movement: electrical, photobiomodulation, micro-osteoperforations, vibration, corticotomy, and low-level laser therapy. The Ottawa method showed that studies produced since 2011 have (1) potentially invalidating evidence and description of new methods and (2) combined new data that would enhance the precision of the existing evidence on low-level laser therapy. These collectively indicate the need for a new systematic review on adjunct procedures to accelerate orthodontic tooth movement, which may offer new evidence and techniques not previously mentioned.
Atomistic simulation of pressure-dependent screw dislocation properties in bcc tantalum

Abstract The pressure-dependent core properties of a /2 〈1 1 1〉 screw dislocations in bcc Ta have been simulated by means of quantum-based, multi-ion interatomic potentials derived from model generalized pseudopotential theory (MGPT). We have considered both ambient-pressure behavior and the change in core properties under high-pressure of 10 Mbar. Robust two- and three-dimensional Green’s function techniques have been used to dynamically relax the boundary forces during the simulations. Our results show that the predicted degenerate core structure is sensitive to pressure, being nearly symmetric and only weakly polarized at ambient pressure, while becoming highly polarized with a distinctive three-fold spread out along 〈1 1 2〉 directions at high-pressure. At the same time, the pure-shear Peierls stress is found to scale linearly with the pressure-dependent 〈1 1 1〉 shear modulus G . The degenerate nature of the core structure leads to multiple possible kinks and kink pairs that can form on the dislocation line at finite temperature. The pressure variation of the lowest kink-pair formation energy reveals a very approximate scaling behavior in terms of G and the Burgers vector.
IMPACT OF SLOT HARMONICS ON LOSSES OF HIGH-SPEED PERMANENT MAGNET MACHINES WITH A MAGNET RETAINING RING

ABSTRACT This paper presents an analytical method for determining the harmonic content in the flux pattern of permanent magnet synchronous machines due to the slotting of the stator. The analysis based on a rotor construction with magnets radially magnetized and a retaining ring to support them against the centrifugal forces. Expressions for the eddy current losses in the magnets and their retaining ring are derived in terms of the machine dimensions and the physical properties of magnets and ring. The accuracy of the method is examined by comparison with numerical flux calculations using finite element method. The impact of some physical quantities like machine speed and magnet conductivity on the slot harmonics losses is examined aiming to exhibit the role of the magnet retaining ring in contributing to these losses
LOAD-INDUCED STRESS SINGULARITIES IN THE BENDING OF COSSERAT PLATES.

Presented in this paper are the solutions to several plate bending problems as governed by a recent theory developed by Green and Naghdi, into which couple-stress is incorporated. Specifically, each problem considered is subjected to boundary conditions emanating from a singular load distribution acting on the free edge of a semi-infinite plate. The method of integral transforms is applied in the solutions. In general, it is found that the singularities in the shear and moment resultants are of the same order as those given in Reissner's plate theory, however the detailed structures of these singular functions are altered. The present theory also suggests that, in most cases, the maximum magnitudes of the moment resultants are diminished as compared to the corresponding results given in Reissner's theory. Also discussed is the exact relationship between the Green-Naghdi theory and Reissner's theory.
Analysis of Z-pinch shock wave experiments on meteorite and planetary materials

Abstract The response of a range of meteorite and planetary materials of astrophysical and planetary science interest to pulsed high-energy-density soft X-ray irradiation from the Sandia National Laboratories Z-pinch accelerator is described. These materials include selected iron and stony meteorites, magnesium-rich olivine (dunite), and Al and Fe calibration materials. In each experiment, the motion of the rear surface of the sample was monitored by velocity interferometry. From the resulting waveform and information about the incident pulse, information about the radiation coupling and the response of the sample to stress waves was deduced. The primary Planckian Z-pinch soft X-ray stagnation emissions have black body equivalent temperatures in the range 170–237 eV, with ∼1–10% K-alpha radiation derived from the pinch material (Cu, Al, Ni or steel). Hohlraum intensities at the stagnation pinch were in the range 84–316 TW/cm 2 on time scales from 3.0 to 8.2 ns, and from 43 to 260 GW/cm 2 at the sample positions 7–14 cm away from the pinch center, assuming an inverse-square radial dependence along a line-of-sight distance. This is analytically estimated to generate target surface radiation pressure of 6.1–12.4 GPa. The very short duration of the loading pulse establishes an attenuating shock wave. Consistent pressure measurements on the calibration targets' rear surfaces suggest a uniform soft X-ray beam on the calibration target surfaces while the (inhomogeneous) natural materials yield Hugoniot pressures with considerable variance, as expected. Thusfar we have not recovered the targets, precluding post-irradiation analysis.
Quantitative planar rest-redistribution 201Tl imaging in detection of myocardial viability and prediction of improvement in left ventricular function after coronary bypass surgery in patients with severely depressed left ventricular function.

BACKGROUNDAlthough many patients with multivessel coronary artery disease (CAD) and severely depressed left ventricular (LV) function will benefit from coronary artery bypass graft surgery (CABG), surgeons may be reluctant to perform CABG on these patients without evidence of myocardial viability in regions of severe asynergy. We hypothesized that quantitative planar rest-redistribution 201Tl imaging would identify viable myocardium and predict improved regional and global function after revascularization in patients with depressed LV function and CAD.METHODS AND RESULTSTwenty-one patients (mean LV ejection fraction, 0.27 +/- 0.05) were studied. Regional and global LV functions were evaluated before and 8 weeks after CABG with radionuclide ventriculography. Segments were prospectively classified as showing normal, mildly reduced, or severely reduced viability on the basis of quantitative analysis of defect severity and redistribution on planar resting 201Tl imaging. By 201Tl criteria, 90% of hypokinetic s...
Avascular necrosis of bilateral knees secondary to corticosteroid enemas

Avascular necrosis (AVN) is a devastating adverse effect of corticosteroid therapy rarely reported in the setting of inflammatory bowel disease. We describe a 48-year-old woman with 6 weeks of progressive bilateral knee pain resulting in the inability to ambulate. Her symptoms developed suddenly, 9 months after treatment with hydrocortisone enemas for ulcerative proctitis. On physical examination, the patient had knee tenderness, decreased range of motion, and flexion contractures. Magnetic resonance imaging showed multiple bony infarcts in bilateral distal femora and proximal tibias, consistent with advanced AVN. Initial therapy included pain management, serial casting, gentle flexibility and strengthening, and limited mobility training. The rehabilitation efforts led to functional improvement. Ultimately, bilateral total knee arthroplasties were recommended to treat her advanced AVN. This is the first reported case of AVN secondary to hydrocortisone enemas. We review the literature and discuss the pathophysiology and management of corticosteroid-induced AVN.
Nonlinear Inverse Perturbation in Structural Dynamics Redesign of Risers

Marine risers, and offshore structures in general, may have undesirable natural frequencies and/or mode shapes. Structural redesign is mandatory in such cases. An Inverse Perturbation Redesign (IPR) method, which uses only the finite element analysis of the baseline system and was developed in previous work for general structures, is extended in this work to handle systems with geometric stiffness matrices like marine risers. The IPR method is currently applicable to undamped structural systems or systems with Rayleigh damping and is valid for large or small changes which are frequently required to change modal characteristics of offshore structures.
Information processing biases and panic disorder: Relationships among cognitive and symptom measures

To test cognitive models of panic disorder, a range of information processing biases were examined among persons with panic disorder (N=43) and healthy control participants (N=38). Evidence for automatic associations in memory was assessed using the Implicit Association Test, interference effects related to attention biases were assessed using a modified supraliminal Stroop task, and interpretation biases were assessed using the Brief Body Sensations Interpretation Questionnaire. In addition, the relationship between information processing biases and clinical markers of panic (including affective, behavioral, and cognitive symptom measures) was investigated, along with the relationships among biases. Results indicated more threat biases among the panic (relative to control) group on each of the information processing measures, providing some of the first evidence for an implicit measure of panic associations. Further, structural equation modeling indicated that the information processing bias measures were each unique predictors of panic symptoms, but that the bias indicators did not relate to one another. These findings suggest that cognitive factors may independently predict panic symptoms, but not covary. Results are discussed in terms of their support for cognitive models of panic and the potential for automatic versus strategic processing differences across the tasks to explain the low relationships across the biases.
Cadmium and lead in Lake Ontario salmonids.

Currently, there are data documenting the existence of cadmium and lead in Lake Ontario salmonids. Investigators recently reported the absence of detectable residues of either element in edible fillets of coho and chinook salmon from Michigan tributaries to the other four laurention Great Lakes. However, flame atomic absorption spectrometry was used and the reported detectability limit (10 ppm) was greater than the trace levels that may likely have been present. The present investigation was initiated to (1) establish the existence and magnitude of cadmium and lead content of Lake Ontario salmonids, and (2) to assess the potential impact of their consumption on human dietary cadmium and lead intake.
Brain functions and neural dynamics

Anatomical and physiological evidence is cited for the existence in the CNS of more or less discrete populations of interconnected neurons. These are given the term netlets. A model based on these observations is presented, in which it is assumed that the netlets are the fundamental building blocks out of which nets of considerable complexity may be as embled. The connectivity within each netlet is assumed to be random. Neuronal macrostates are defined in which the fractions of neurons active in each netlet are the dynamical variables. Thus the temporal and spatial fine structure of neuronal activity are considered to be of secondary significance and are disregarded. These assumptions bring about an enormous reduction in complexity. Thus calculations and computer simulation studies become possible for systems hitherto inaccessible to quantitative description. It is hoped that the features retained in the model play a sufficiently significant role in the functioning of real neural nets to make these results meaningful. The mathematical formalism and detailed numerical results appear in another paper of this issue ( Anninos, 1970 ). Some of these results are anticipated in this paper and their implications for our model are discussed. The study proceeds from a treatment of isolated probabilistic netlets to the dynamics of interacting netlets. Of particular interest are the conditions under which a netlet will go into sustained activity and the often extremely delicate control exerted by afferent excitatory or inhibitory biases. Hysteresis effects are common and may represent a type of short-term memory. A variety of neural functions are listed to which some of these mechanisms may be applied. Among these are the modulating effects of the brain stem reticular formation on cortical and spinal neuron populations and the “energizing” of cortical centers by spontaneous activity in sensory systems. Finally the concepts of netlet interaction are applied in conjunction with the principle of synaptic facilitation to information processing in the cortex. Examples given are sensory-sensory cortical conditioning and the formation of the classical conditioned reflex.
Characterization of a nondeleterious L1 insertion in an intron of the human factor VIII gene and further evidence of open reading frames in functional L1 elements

Abstract We have characterized an insertional event in IVS-10 of the factor VIII gene in a pedigree containing a hemophilia A patient (JH-25). The inserted DNA is a 5′ truncated L1 element that is 681 bp long followed by a 3′66-bp poly(A) tract. The L1 element is inserted 154 bp 5′ to the start of exon 11 and is flanked by a 13- to 17-bp target site duplication. The L1 insertion is present in four generations of the patient's family. The maternal grandfather who carries the insertion does not have hemophilia A, indicating that the insertion is not the cause of hemophilia A in the patient. We have sequenced this insertion and two previously reported de novo L1 insertions in the factor VIII gene in patients JH-27 (3785 bp) and JH-28 (2132 bp). The three nucleotide sequences differ by 0.2–0.8%. All three of these L1 insertions have open reading frames (ORFs) (1192, 642, and 157 aa) and the three derived amino acid sequences are 98–99% identical. The previously reported sequence similarity between L1 3′ ORFs and the polymerase domain of reverse transcriptases is maintained in the ORFs of the JH-27 and JH-28 L1 insertions. The presence of open reading frames and the close sequence similarity of these recently inserted L1 elements provide indirect evidence for the existence of a set of functional L1 elements that encode one or more proteins necessary for their retrotransposition.
A functional scaling approach to electromagnetic scattering by particulates: theory and algorithms for spheres and cylinders

Abstract A functional scaling approach to computing the electromagnetic (em) scattering coefficients ( a n , b n ) is described and used to develop a unified theory of em scattering for infinite cylinders and spheres. Scattering algorithms based on the unified theory and scaled Bessel functions are described.
Probing ADAMTS13 substrate specificity using phage display.

Von Willebrand factor (VWF) is a large, multimeric protein that regulates hemostasis by tethering platelets to the subendothelial matrix at sites of vascular damage. The procoagulant activity of plasma VWF correlates with the length of VWF multimers, which is proteolytically controlled by the metalloprotease ADAMTS13. To probe ADAMTS13 substrate specificity, we created phage display libraries containing randomly mutated residues of a minimal ADAMTS13 substrate fragment of VWF, termed VWF73. The libraries were screened for phage particles displaying VWF73 mutant peptides that were resistant to proteolysis by ADAMTS13. These peptides exhibited the greatest mutation frequency near the ADAMTS13 scissile residues. Kinetic assays using mutant and wild-type substrates demonstrated excellent agreement between rates of cleavage for mutant phage particles and the corresponding mutant peptides. Cleavage resistance of selected mutations was tested in vivo using hydrodynamic injection of corresponding full-length expression plasmids into VWF-deficient mice. These studies confirmed the resistance to cleavage resulting from select amino acid substitutions and uncovered evidence of alternate cleavage sites and recognition by other proteases in the circulation of ADAMTS13 deficient mice. Taken together, these studies demonstrate the key role of specific amino acids residues including P3-P2’ and P11’, for substrate specificity and emphasize the importance in flowing blood of other ADAMTS13–VWF exosite interactions outside of VWF73.
The Comparative Reception of Darwinism: A Brief History.

The subfield of Darwin studies devoted to comparative reception coalesced around 1971 with the planning of a conference on the subject, at the University of Texas at Austin held in April 1972. The original focus was western Europe, Russia and the United States. Subsequently a spate of studies on the Italian reception added to the Eurocentric focus. The center of activity then switched to Latin America where a group of scholars coalesced in the mid 1990s, seemingly related to the maturation of the history of science as a discrete discipline there somewhat earlier. When interest in Europe revived during the last decade, the center of gravity had moved both eastward, to the former Society bloc countries (a reflection of the institutionalization of the history of science there), and north to Scandinavia. Recently, interest in the topic has emerged in the Islamic World. The subtext of the expansion of this topic is modernization.
Giant keratoacanthoma: a problem in diagnosis and management.

A case of giant keratoacanthoma of the nose and paranasal areas is presented. Following a prolonged and stormy course, the tumor eventually involuted spontaneously, leaving in its wake significant destruction of an ala nasi. This report illustrates the problems of attempting to predict the natural history of a particular keratoacanthoma and the difficulties in managing an agressive-type tumor of this type.
Microstructural instability in single-crystal thin films

Epitaxial PbTiO3 thin films were produced from a mixed Pb–Ti double-alkoxide precursor by spin-coating onto single crystal (001) SrTiO3 substrates. Heat treatment at 800 °C produces a dense and continuous, epitaxial lead titanate film through an intermediate Pb-Ti fluorite structure. A microstructural instability occurred when very thin single crystal films were fabricated; this instability caused the films to become discontinuous. Scanning electron microscopy and atomic force microscopy observations show that single crystal films with a thickness less than ∼80 nm developed holes that expose the substrate; thinner films broke up into isolated, single crystal islands. The walls of the holes were found to be (111) perovskite planes. A free energy function, which considered the anisotropic surface energies of different planes, was developed to describe the microstructural changes in the film and to understand the instability phenomenon. The function predicted that pre-existing holes greater than a critical size are necessary to initiate hole growth, and it predicted the observed morphological changes in the current system. Morphological stability diagrams that explain the stability fields for different film configurations, i.e., either completely covered, with holes, or single crystal islands, can be calculated for any film/substrate system.
Erythrocyte defenses against hydrogen peroxide: the role of ascorbic acid

Ascorbate has been reported to increase intracellular hydrogen peroxide (H2O2) generation in human erythrocytes. In the present work, the basis for this prooxidant effect of the vitamin was investigated in the context of erythrocyte defenses against H2O2. Ascorbate added to erythrocytes caused a dose-dependent increase in intracellular H2O2, which was measured as inactivation of endogenous catalase in the presence of 3-amino-1,2,4-triazole (aminotriazole). Ascorbate-induced catalase inactivation was not observed when only the intracellular ascorbate concentration was increased, when cells were incubated with ascorbate in plasma, or when extracellular Fe3+ was chelated. Together, these results suggest that the observed ascorbate-induced H2O2 generation is due to Fe3+-catalyzed oxidation of extracellular, as opposed to intracellular, ascorbate by molecular oxygen. Rather than generate an oxidant stress in erythrocytes, ascorbate was one of the most sensitive intracellular antioxidants to H2O2 coming from outside the cells. On the other hand, intracellular ascorbate contributed little to the detoxification of H2O2, which was found to be mediated by both catalase and by the GSH system.
Force exerted on a single spherical particle by a freezing interface: Theory

Abstract At low freezing rates V, the maximum force Fmax exerted on a fixed spherical particle by a freezing interface is predicted to vary as 1/V, 1/V1.42, or 1/V2, depending on the exact model employed. Similarly, the dependence on particle radius R is predicted to vary as 1/R or 1/R1.73. One model predicts a dependence on the imposed temperature gradient, while the other two do not. The critical freezing rate Vc for engulfment of an unrestrained particle is predicted to vary as 1/R 4 3 for small particles and 1/R for large particles. If a large external force F is applied, Vc becomes proportional to 1/RF for small particles and 1/(RF) 1 2 for large particles. If this external force is due to gravity, then F depends on the volume of the particle and Vc is expected to vary as 1/R4 or 1/R2.
Three-dimensional computed tomography-based spinal navigation in minimally invasive lateral lumbar interbody fusion: feasibility, technique, and initial results.

Background As with most minimally invasive spine procedures, lateral lumbar interbody fusion (LLIF) requires the use of biplanar fluoroscopy for localization and safe interbody cage placement. Computed tomography (CT)-based intraoperative spinal navigation has been shown to be more effective than fluoroscopic guidance for posterior-based approaches such as pedicle screw instrumentation. However, the use of spinal navigation in LLIF has not been well studied. Objective To present the technique for using an intraoperative cone-beam CT and image-guided navigation system in LLIF and to provide a preliminary analysis of outcomes. Methods We retrospectively analyzed a prospectively acquired database and the electronic records of patients undergoing LLIF with spinal navigation. Eight patients were identified. Postoperative neurological deficits were recorded. All patients underwent postprocedural CT and x-ray imaging for analysis of accuracy of cage placement. Accuracy of cage placement was determined by location within the disk space. Results The mean age was 66 years, and 6 patients were women. A mean 2.8 levels were treated with a total of 22 lateral cages implanted via navigation. All cages were placed within quarters 1 to 2 or 2 to 3, signifying the anterior half or middle portions of the disk space. There were no sensory or motor deficits postoperatively. Conclusion Use of an intraoperative cone-beam CT with an image-guided navigation system is feasible and safe and appears to be accurate, although a larger study is required to confirm these results.