cssi/SciSciGPT-SciSciNet huggingface dataset:
Evolution of the genetic code based on conservative changes of codons, amino acids, and aminoacyl tRNA synthetases

The genetic code, as arranged in the standard tabular form, displays a non-random structure relating to the characteristics of the amino acids. An alternative arrangement can be made by organizing the code according to aminoacyl-tRNA synthetases (aaRSs), codons, and reverse complement codons, which illuminates a coevolutionary process that led to the contemporary genetic code. As amino acids were added to the genetic code, they were recognized by aaRSs that interact with stereochemically similar amino acids. Single nucleotide changes in the codons and anticodons were favored over more extensive changes, such that there was a logical stepwise progression in the evolution of the genetic code. The model presented traces the evolution of the genetic code accounting for these steps. Amino acid frequencies in ancient proteins and the preponderance of GNN codons in mRNAs for ancient proteins indicate that the genetic code began with alanine, aspartate, glutamate, glycine, and valine, with alanine being in the highest proportions. In addition to being consistent in terms of conservative changes in codon nucleotides, the model also is consistent with respect to aaRS classes, aaRS attachment to the tRNA, amino acid stereochemistry, and to a large extent with amino acid physicochemistry, and biochemical pathways.
Elevated CO2 alters behavior, growth, and lipid composition of Pacific cod larvae.

Abstract High-latitude seas, which support a number of commercially important fisheries, are predicted to be most immediately impacted by ongoing ocean acidification (OA). Elevated CO2 levels have been shown to induce a range of impacts on the physiology and behavior of marine fish larvae. However, these responses have yet to be characterized for most fishery species, including Pacific cod (Gadus macrocephalus). Based on laboratory experiments, we present a multi-faceted analysis of the sensitivity of Pacific cod larvae to elevated CO2. Fish behavior in a horizontal light gradient was used to evaluate the sensitivity of behavioral phototaxis in 4–5 week old cod larvae. Fish at elevated CO2 levels (∼1500 and 2250 μatm) exhibited a stronger phototaxis (moved more quickly to regions of higher light levels) than fish at ambient CO2 levels (∼600 μatm). In an independent experiment, we examined the effects of elevated CO2 levels on growth of larval Pacific cod over the first 5 weeks of life under two different feeding treatments. Fish exposed to elevated CO2 levels (∼1700 μatm) were smaller and had lower lipid levels at 2 weeks of age than fish at low (ambient) CO2 levels (∼500 μatm). However, by 5 weeks of age, this effect had reversed: fish reared at elevated CO2 levels were slightly (but not significantly) larger and had higher total lipid levels and storage lipids than fish reared at low CO2. Fatty acid composition differed significantly between fish reared at high and low CO2 levels (p
Inverse Methods to Improve Accuracy of Water Content Estimates from Multi-offset GPR

ABSTRACT Ground penetrating radar (GPR) is a powerful hydrogeophysical tool for estimating porosity and water content of geologic materials using radar wave velocities and appropriate petrophysical...
Chemical induction of interleukin-8, a proinflammatory chemokine, in human epidermal keratinocyte cultures and its relation to cytogenetic toxicity.

Tumor promoters, proinflammatory cytokines, endotoxins, and protein synthesis inhibitors can modulate cell cycle kinetics of various cell types, stimulate production of reactive oxygen species, and induce keratinocytes to produce interleukin-8 (IL-8), a potent chemotactant for polymorphonuclear neutrophils and T lymphocytes. The aim of this study was to determine whether perturbations of cytogenetic responses correlated with the induction of IL-8 expression. Cultures of primary human keratinocytes were grown in serum-free medium with 5 μmol/L bromodeoxyuridine to label DNA and exposed either to phorbol-13-myristate-12-acetate (PMA) (0.0001–100 ng/ml), cycloheximice (CHX) (0.01–50 μg), lipopolysaccharide (0.1–100 μg/ml), tumor necrosis factor-α (TNFα) (3.13–50 ng/ml), or interleukin-1α (IL-1α) (1–182 pg/ml). Metaphase chromosome preparations were stained by a fluorescence-plus-Giemsa technique to differentiate sister chromatids. For IL-8 production, keratinocytes were grown to 70% confluency and then exposed to chemicals for 24 h. Immunoreactive IL-8 was quantitated from the supernatants by ELISA. With the exception of benzo(a)pyrene used as a positive control, none of the agents induced sister chromatid exchanges. However, PMA and TNFα induced IL-8 production that coincided with significant cell cycle inhibition. IL-1α had no effect on cytogenetic endpoints, yet stimulated a 6.3-fold increase in IL-8. CHX inhibited cell cycle progression and mitotic activity at concentrations that were 200 times lower than required for IL-8 induction; however, puromycin (0.31–10 μg/ml), another protein synthesis inhibitor, did not induce IL-8. At all concentrations tested, TNFα reduced the mitotic index by ∼45%, slowed cell cycle progression by ∼3.5 h, and induced a flat, albeit large, IL-8 response at concentrations ≥12.5 ng/ml. These agent-specific response patterns suggest that induction of IL-8 production is not always the inevitable result of cell cycle perturbations or genetic damage.
Explaining the College Choice Decisions of International Students at a Regional University in the United States

Numerous institutions list hosting and recruiting international students as an important aspect of their internationalization mission. Reasons include the financial benefit to the institution and t...
Tissue-, age- and dose-dependent changes in avian β-defensin and LEAP2 mRNA abundance in the intestines of Salmonella Typhimurium challenged broilers.

Salmonella is a pathogen normally found in the gastrointestinal tract of poultry. The objective of this study was to determine changes in avian β-defensin (AvBD) and liver-enriched antimicrobial pe...
A Meta-Analysis of Blood Pressure Disparities Among Sexual Minority Men.

Purpose: The aim was to review and summarize reports on three measures of elevated blood pressure (BP) among sexual minority men (encompassing men who have sex with men [MSM] and both men and women...
Drosophila reward system - A summary of current knowledge

Abstract The fruit fly Drosophila melanogaster brain is the most extensively investigated model of a reward system in insects. Drosophila can discriminate between rewarding and punishing environmental stimuli and consequently undergo associative learning. Functional models, especially those modelling mushroom bodies, are constantly being developed using newly discovered information, adding to the complexity of creating a simple model of the reward system. This review aims to clarify whether its reward system also includes a hedonic component. Neurochemical systems that mediate the ‘wanting’ component of reward in the Drosophila brain are well documented, however, the systems that mediate the pleasure component of reward in mammals, including those involving the endogenous opioid and endocannabinoid systems, are unlikely to be present in insects. The mushroom body components exhibit differential developmental age and different functional processes. We propose a hypothetical hierarchy of the levels of reinforcement processing in response to particular stimuli, and the parallel processes that take place concurrently. The possible presence of activity-silencing and meta-satiety inducing levels in Drosophila should be further investigated.
Climate Disasters and Financial Fundamentals

I propose a rare disaster model of an economy where disasters are driven by CO2 levels that are determined by inputs of carbons from the firms of the economy. The probability and intensity of disaster are determined in part by the level of CO2 in the environment. In turn, disasters affect the budgets, the labor allocations and investment decisions of households; the production and investment decisions of firms; and, monetary policy. Prices are determined in equilibrium. From this model, Six propositions are developed relating carbon dioxide levels and climatic economic damages to the financial variables: the risk free rate, the price dividend ratio, and the risk premium. The six propositions are then tested empirically using a unique data set for the United States over the period from March 1958 to December 2018. The data is found to support the six propositions. In general, carbon use, as proxied by the carbon dioxide level, lowers the risk free rate and price dividend ratio, while raising the risk premium. Climatic economic damages raise the risk free rate, while lowering the price dividend ratio and risk premium. However, if the probability of climatic disaster rises sufficiently, these relationships can change. I then briefly discuss some implications of these results.
Clinical Significance of Screening Electrocardiograms for the Administration of Propranolol for Problematic Infantile Hemangiomas.

Objective. Low-dose nonselective β blockade is an effective treatment for problematic infantile hemangioma (PIH). Screening electrocardiograms (ECG) are performed prior to the initiation of propranolol to minimize the risk of exacerbating undiagnosed heart block. How ECG results affect subsequent propranolol usage and patient management remains unclear. We examined the value of ECG prior to propranolol therapy in a quaternary pediatric hospital. Methods. A retrospective chart review was performed on all infants who received propranolol (2 mg/kg/day divided three times daily) to treat PIH at Arkansas Children’s Hospital from Sept. 2008 to Sept. 2015. All available demographic, historical, and clinical data were obtained. ECGs and echocardiographic data were reviewed and summarized. A pediatric cardiologist read all ECGs. Results. A total of 333 patients (75% female) received propranolol therapy. ECG information was available for 317 (95%). Abnormal findings were present on 44/317 (13.9%) of study ECGs. The most common abnormal finding was “voltage criteria for ventricular hypertrophy” ( , 76.1%). Two patients had abnormal rhythms; one had first-degree atrioventricular (AV) block, and one had occasional premature atrial contractions. Of the 31 patients who underwent echocardiograms, 20 (35%) were abnormal. 2.9% of infants with PIH treated with propranolol required a follow-up with a cardiologist. No patient was precluded from taking propranolol due to the findings on screening ECG. Conclusions. Screening ECGs prior to propranolol therapy are abnormal in nearly 14% of patients with PIH but are unlikely to preclude therapy. In the absence of prior cardiac history, this cohort offers further evidence suggesting that screening ECGs may be of limited value in determining the safety of propranolol in otherwise healthy infants with PIH.
Does exposure to poultry and wild fowl confer immunity to H5N1

Human outbreaks of highly pathogenic avian influenza (HPAI) such as H5N1 and novel avian strains such as H7N9 have provoked significant public health concern. An outbreak of H5N1 in humans was first reported in Hong Kong (HK), China in 1997. This event was curtailed by a variety of public health measures including the culling of over 1.5 million chickens in the city.1 H5N1 has since re-emerged in multiple countries with over 600 reported infections and, since 2003, a case fatality of about 59% (World Health Organization (WHO) report, as of January 24, 2014). A clear picture of the prevalence and transmissibility of avian influenza strains in humans is lacking, in part due to sparse epidemiological data and limitations in current detection methods. A recent meta-analysis estimated a 1.2% (95% CI: 0.6%–2.1%) seropositive rate for H5N1 in humans.2 Here we argue that H5N1 seroprevalence could be region specific, due to differing levels of exposure to wild and domestic fowl. We hypothesize that persistent environmental exposure to avian influenza strains may enhance cross-immunity against HPAI strains such as H5N1, and thus lower H5N1 seropositive rates. In contrast, people with limited exposure to poultry and wild birds may have less cross-immunity against HPAI (e.g., H5N1) and thus could be more susceptible to the virus. Our hypothesis is supported by two independent lines of evidence: one epidemiological, and the other immunological. The former evidence shows that populations with frequent exposure to poultry have lower H5N1 seropositive rates; the latter indicates that cross-immunity between human and avian strains exists and its strength may depend on the frequency of exposure. Each of these lines of evidence is detailed herewith.
Photoelectric performance of TiO2 nanotube array photoelectrodes sensitized with CdS0.54Se0.46 quantum dots

Abstract The photoelectrochemical performance of CdSSe quantum dots tethered to a framework of vertically oriented titania (TiO2) nanotubes was studied. The TiO2/CdSSe framework demonstrated improved charge transfer due to its unique band edge structure, thus validating the higher photocurrent generation. The composite film led to an 11-fold enhancement in comparison to the control TiO2 film, implying that the ternary quantum dots and the nanotubular structure of TiO2 work in tandem to promote charge separation and favorably impact photoelectrochemical performance. Further, the results also suggest that structural and optoelectronic properties of TiO2 films are significantly affected by the thicknesses of the CdSSe layer.
Performance, Herding, and Career Concerns of Individual Financial Analysts

Using a new database of stock recommendations with substantially expanded coverage of brokerage firms and individual analysts, I examine the performance of portfolios recommended by individual analysts. The analysis allows a more accurate measurement of analyst performance with extensive risk adjustments. I show that at the aggregate level, analyst portfolios generate significant abnormal returns. Individually, a large number of analysts significantly outperform risk-adjusted benchmarks and there are at least twice as many analysts who significantly outperform as analysts who significantly underperform benchmarks. Abnormal performance is generated mainly within a narrow event window from two trading days before the recommendation date to five trading days later, with no significant post-event return drift. In addition, analyst performance improves with the number of recommendations issued, the number of stocks covered, and the size of their brokerage firms. However, performance declines as their coverage goes beyond 12-13 stocks. All-American analyst ranking of Institutional Investor cannot predict analyst performance. Moreover, analysts career concerns have significant impact on their behavior. Analysts with more reputation capital at stake recommend less risky portfolios and deviate less from the herd. Analyst behavior is also predictable on the basis of several other characteristics. Furthermore, I provide evidence for the current debate on how to reform analyst compensation. I find although the II all-star ranking is significantly related to performance, it is affected more by recognition factors and reputation factors. Its capacity to serve as a performance-based evaluation system for analyst compensation is quite limited.
A Canadian's View from the Staten Island Ferry

This article discusses the Civil Court on Staten Island (Richmond County), New York, and some of Staten Island's legal history.
Geographic variation of epilepsy for older Americans: How close to the geographic variation of stroke?

SUMMARY Purpose: Given the strong association of stroke and epilepsy in older persons, and the existence of a Stroke Belt in the United States, we hypothesized that geographic variation in epilepsy prevalence would follow geographic patterns similar to stroke. Methods: We used a 2005 5% random sample of Medicare beneficiaries 65 and older in 48 U.S. contiguous states. Epilepsy was identified from claims for physician visits, hospitalizations, and outpatient procedures. Prevalence was obtained by state and county. Logistic regressions determined the independent association of the likelihood of epilepsy (prevalent or new case) and residence in Stroke Belt states, controlling for residence in highest epilepsy prevalence states, demographics (race, age, gender), comorbid conditions, cerebrovascular disease, dementia, and county characteristics. Key Findings: Of 1,212,015 beneficiaries, 11.9 per 1,000 had prevalent and 2.9 new cases of epilepsy. Nine of 11 Stroke Belt states were among the 20states with the highest epilepsy prevalence. Counties in the 10 highest epilepsy prevalence states were more likely to be large urban counties with a higher number of neurologists or neurosurgeons per capita. The higher likelihood of prevalent epilepsy cases associated with Stroke Belt residence was explained by beneficiaries’ race; that associated with residence in high epilepsy prevalence states was not. The likelihood of new epilepsy cases was negatively associated with Stroke Belt residence when controlling for covariates.
Human Movement Measurements

Making movements and detecting and interpreting the movement of others are crucial for humans. Technological advancement is constantly providing new opportunities where human movement must be observed and interpreted accurately. The constantly expanding, areas of application for human motion measurement have motivated the development or adoption of a number of measurement technologies including optical, magnetic, and inertial motion measurement systems. These measurement systems have been used successfully in many applications, but they have limitations and their application has faced many challenges that are subjects of continued research. The study also emphasizes that by acquiring raw data about human movement, it is important to consider how the data are analyzed and presented. Depending on the application, the same human motion can be described in varying levels of detail and from different perspective. It has been noticed that none of the existing measurement systems satisfy all of the requirements, but they offer range of possibilities that must be carefully considered for a specific application. Keywords: hybrid inertial-magnetic systems; inertial sensing; integration drift; micro-electro-mechanical systems; optical motion capture system
Entering a Program: Helping Students Make Academic and Career Decisions

In this literature review, the author examines the evidence on student decision making in the community college, focusing on the activities most relevant to students’ entry into programs of study—academic and career planning. Although there is a large body of theoretical discussion and empirical evidence on potentially effective approaches to guidance and counseling, a review of current advising and counseling practices reveals barriers to effective implementation of these approaches on community college campuses. As currently structured, community college advising is limited in its ability to assist students in identifying career goals and academic pathways that will help them achieve those goals. The literature reviewed in this paper points to four broad principles to guide restructuring efforts: (1) that program pathways should balance structure with exploration; (2) that career counseling should drive an integrated approach to advising; (3) that colleges should provide services to students based on their level of need; and (4) that colleges should strategically deploy resources to allow for developmental advising.
Sequence and expression of a type II keratin, K5, in human epidermal cells.

Abstract We report here the cDNA and amino acid sequences of a human 58-kilodalton type II keratin, K5, which is coexpressed with a 50-kilodalton type I keratin partner, K14, in stratified squamous epithelia. Using a probe specific for the 3'-noncoding portion of this K5 cDNA, we demonstrated the existence of a single human gene encoding this sequence. Using Northern (RNA) blot analysis and in situ hybridization with cRNA probes for both K5 and K14, we examined the expression of these mRNAs in the epidermis and in cultured epidermal cells. Our results indicate that the mRNAs for K5 and K14 are coordinately expressed and abundant in the basal layer of the epidermis. As cells undergo a commitment to terminally differentiate, the expression of both mRNAs seems to be downregulated.
GCAP1 Mutations Associated with Autosomal Dominant Cone Dystrophy

We discuss the heterogeneity of autosomal dominant cone and cone-rod dystrophies (adCD, and adCORD, respectively). As one of the best characterized adCD genes, we focus on the GUCA1A gene encoding guanylate cyclase activating protein 1 (GCAP1), a protein carrying three high affinity Ca2+ binding motifs (EF hands). GCAP1 senses changes in cytoplasmic free [Ca2+] and communicates these changes to GC1, by either inhibiting it (at high free [Ca2+]), or stimulating it (at low free [Ca2+]). A number of missense mutations altering the structure and Ca2+ affinity of EF hands have been discovered. These mutations are associated with a gain of function, producing dominant cone and cone rod dystrophy phenotypes. In this article we review these mutations and describe the consequences of specific mutations on GCAP1 structure and GC stimulation.
Structure of the hamster low density lipoprotein receptor gene.

The metabolism of low density lipoprotein (LDL) in the hamster is substantially similar to that of the human. To extend the usefulness of the hamster as an experimental model, the hamster LDL receptor gene was isolated and characterized. The gene is composed of 18 exons and 17 in- trons which span 26 kilobases. The introns occur at precisely the same positions as those previously determined for the human LDL receptor gene. The 18 exons of the hamster gene predict an LDL receptor protein of 854 amino acids that is similar in organization and sequence to those predicted from the cDNAs of rat, rabbit, cow, and human. Within the 5'-flanking region of the hamster LDL receptor gene are three highly conserved imperfect direct repeat se- quences of 16 nucleotides each that in the human gene have been demonstrated to regulate transcription. In addi- tion, a similar arrangement of direct repeat sequences was also isolated from the 5'-flanking region of the rat LDL receptor gene using the polymerase chain reaction. These results indicate a strong sequence and structural con- servation of the LDL receptor among several species and further support the hamster as an experimental model for the study of human LDkholesterol metabolism.-Bishop, R. W. Structure of the hamster low density lipoprotein receptor gene. J. Lipid Res. 1992.33: 549-557.
Synchronization of temporal constructs in distributed multimedia systems with controlled accuracy

With the inception of technology in communication networks such as ATM, it will be possible to run multimedia applications on future integrated networks. Synchronization of the related media data is one of the key characteristics of a multimedia system. In this paper we present a scheme for synchronization of multimedia data across a network where the accuracy of detecting asynchronization and predicting the future asynchrony is variable and can be tailored to the intended application. The multimedia data when sent across the network may also be stored at an intermediate node and later retrieved for display. We extend the scheme and present a mechanism wherein synchronization of all the possible temporal constructs is supported and not restricted to the "in-parallel" construct which is only one of the thirteen possible temporal relations. >
Internal medicine program directors' perceptions of resident work rounds.

Work rounds have received little atention in the medical education literature. At the outset of the second post graduate year, medical residents are expected to function, without much guidance, as both team leaders and teacher. New York State health code regulation 405 restrict house staff work hours and may influence the manner and content of work rounds. The goals of work rounds were identified through a literature review and our own experiences. A 36-item questionnaire utilizing the identified goals was used in this crosssectional descriptive study. The participants were the Program Directors of New York State Internal Medicine residency programs. Each of the fourteen goals identified reflects one of three resident behaviors: patient care, teaching, and evaluation. The goals that received the highest impotance scores were patient management and updating team leader of events. Nineyty percent (90%) or more of the participants indicated that patient management, teaching clinical reasoning and problem solving, verifying important chart data, and verifying physical examination should be performed “often” or «lmost always.” Most programs emplyed verba instructions but only few held conference or provided literature on the expectations and conduct of work rounds. New York State Internal Medicine program directors perceive work rounds as primarily a patient care task, and many rely on verbal instructions to convey the objectives to the house staff. While previous research has demonstrated that work rounds are an important setting for house staff education, this study reveals that in most new York State programs this opportunity may be missed.
Periductal vessels of the endolymphatic duct.

Light microscope was used to examine the rich vascular plexus surrounding the human endolymphatic duct, both in the periductal loose connective tissue and in the bony channels surrounding the bony vestibular aqueduct. We also performed computer-aided three-dimensional reconstruction on one serially sectioned region of the endolymphatic duct. We found an anastomotic and looping network of vessels residing in the loose connective tissue close to the epithelium of the endolymphatic duct. This network often received a vascular contribution from the vessels in the periaqueductal bony channels. These findings were verified by light microscopic examination of 50 temporal bone specimens. Concurrent with this finding, histologic examination also showed different characteristic features of the vascular system of the endolymphatic duct-proximal sac areas and of the more distal parts of the endolymphatic sac. These features include the arrangement, quantity, and contents of the periaqueductal bony channels, as well a...
A general biophysical model of larval cod (Gadus morhua) growth applied to populations on Georges Bank

Field-derived growth rates (RNA-DNA based) of cod (Gadus morhua) larvae collected on the southern flank of Georges Bank were higher on average in May 1993 than May 1994, despite the apparent higher abundance of potential prey in 1994. A biophysical modeling study is presented here in which factors are examined that may have led to the difference in population mean growth. A one-dimensional physical model, forced by winds and tides, was used to simulate the vertical structure (of currents, temperature field, and turbulent kinetic energy dissipation rate) following a column of water in a Lagrangian sense at a site on the southern flank of Georges Bank over 5-day periods in late May of 1993 and 1994. The biophysical model and observed zooplankton abundance allowed us to explore the vertical structure and temporal (hourly) evolution of feeding and growth for cod larvae in relation to environmental conditions. Our trophodynamic model is improved over previous versions and now includes the effect of light on larval feeding response, as well as the effect of temperature on larval metabolic costs, ingestion, and digestion. Larval prey profiles, comprising four copepod species, were used from a time series of 1/4-m 2 MOCNESS tows to define the prey field. Data from a collateral time-series of larval gut contents (1-m 2 MOCNESS tows) was used to define maximum ingestion (satiation level) and prey selection. Model outputs provide depth-dependent estimates of growth, prey biomass ingested, larval length, and larval weight. Watercolumn growth-rate profiles were made for four size classes of larvae (5, 6, 7 and 9 mm) under the environmental conditions observed in May 1993 and 1994. A weighted-mean growth rate based on the mean vertical distribution of larvae was estimated for each size class. In all cases, when using all available potential prey, the model-derived 1994 growth rates were higher (by 3‐6% day )1 ) than those for 1993. However, simulations in which 7-mm larvae followed the field-derived weighted mean depth over the sampling period, and were limited to their preferred Pseudocalanus prey, resulted in average growth of 12.2% day )1 for 1993 and 9.7% day )1 for 1994. These compared closely to the field growth means of 11.3% day )1 in 1993 and 9.8% day )1 in 1994. Thus, the lower observed growth in May 1994 may have resulted from depth-dependent food limitation and prey-selectivity coupled with the greater metabolic costs induced by the higher temperature that year.
The origin of syn/anti selectivity in the cycloaddition reactions of 7‐substituted norbornadienes

Generalizations which permit the prediction of the syn/anti selectivity in the [π4s + π2s] cyeloadditions of 7-substituted norbornadienes has been developed from perturbation molecular orbital theory. These theoretical predictions are in excellent agreement with all the experimental results reported in the literature. Furthermore, the effect of the 7-substituent of norbornenes on the double bond has been explained by the “through-space” interactions between the substituent and the syn-double bond.
Interactions and phase behavior of a monoclonal antibody

Protein phase behavior is implicated in numerous aspects of downstream processing either by design, as in crystallization or precipitation processes, or as an undesired effect, such as aggregation. An improved understanding of protein phase behavior is, therefore, important for developing rational design strategies for important process steps. This work explores the phase behavior of a monoclonal antibody (mAb), IDEC-152, which exhibits liquid–liquid separation, aggregation, gelation, and crystallization. A systematic study of numerous factors, including the effects of solution composition and pH, has been conducted to explore the phase behavior of this antibody. Phenomena observed include a significant dependence of the cloud point on the cation in sulfate salts and nonmonotonic trends in pH dependence. Additionally, conditions for crystallization of this mAb are reported for the first time. Protein–protein interactions, as determined from the osmotic second virial coefficient, are used to interpret the phase behavior. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Standardized patient outcomes trial (SPOT) in neurology

Background: The neurologic examination is a challenging component of the physical examination for medical students. In response, primarily based on expert consensus, medical schools have supplemented their curricula with standardized patient (SP) sessions that are focused on the neurologic examination. Hypothesis-driven quantitative data are needed to justify the further use of this resource-intensive educational modality, specifically regarding whether using SPs to teach the neurological examination effects a long-term benefit on the application of neurological examination skills. Methods: This study is a cross-sectional analysis of prospectively collected data from medical students atWeill Cornell Medical College. The control group ( n =129) received the standard curriculum. The intervention group ( n =58) received the standard curriculum and an additional SP session focused on the neurologic examination during the second year of medical school. Student performance on the neurologic examination was assessed in the control and intervention groups via an OSCE administered during the fourth year of medical school. A Neurologic Physical Exam (NPE) score of 0.0 to 6.0 was calculated for each student based on a neurologic examination checklist completed by the SPs during the OSCE. Composite NPE scores in the control and intervention groups were compared with the unpaired t-test. Results: In the fourth year OSCE, composite NPE scores in the intervention group (3.5±1.1) were statistically significantly greater than those in the control group (2.2±1.1) ( p <0.0001). Conclusions: SP sessions are an effective tool for teaching the neurologic examination. We determined that a single, structured SP session conducted as an adjunct to our traditional lectures and small groups is associated with a statistically significant improvement in student performance measured 2 years after the session. Keywords: neurology education; neurological examination; standardized patient; OSCE; outcomes (Published: 14 January 2011) Citation: Medical Education Online 2011, 16 : 5634 - DOI: 10.3402/meo.v16i0.5634
Role of control and system theory in economics

While it is no doubt appropriate for this panel to discuss a subject as extensive as the role of control and system theory in economics, prudence requires that I pursue a somewhat more modest objective. Consequently I shall confine my remarks to the application of control theory to macroeconomies, and more narrowly yet to short run macroeconomic policy. The subject area remains vast, of course; perhaps too vast to advance any serious generalizations. Notwithstanding I offer the prediction that over the next decade control theory's contribution to macroeconomic policy determination will be more qualitative than quantitative. By this I mean it is unlikely that control theory will be used to generate specific policy directives to guide the economy in the same manner that it generates controls to guide a missile. Instead I believe it will be used primarily to provide insights as to the appropriate policy structure.
Development of knife-edge field emission cathodes on (110) silicon wafers

Knife-edge field emission cathodes have been fabricated on (110) silicon wafers. The emitter structure consists of an array of razor shaped silicon knife edges standing up on silicon substrates. The radii of the sharp edges seen with SEM are less than 250 A; the height of the knife edges is 5 to 8 μm; and the gate-emitter spacing is ∼0.1 μm. Because of the very small gate-emitter spacing and the large height/width ratio of the emitter, the structure resembles an optimized emitter geometry concluded from our study. The fabrication process and results are presented.
MINERALOGICAL ANALYSES OF CERAMIC MATERIALS FROM QUINUA, DEPARTMENT OF AYACUCHO, PERU

SUMMARY OF RESULTS Three basic results emerge from the study of ceramic raw materials in Quinua, Peru. First of all, a substantial amount of mineralogical variability exists in these materials. Secondly, plastic minerals and non-plastic materials occur in both clays and tempers. The difference between the clays and tempers is the relative amount of plastics or non-plastics present. Thirdly, all of the paints consist of mineral pigments and all contain the clay mineral montmorillonitc -a material known for its superior spreading qualities. DISCUSSION OF RESULTS The results of the analyses have several implications for the archaeologist. First of all, it shows the diversity of sources and mineralogical variability of ceramic materials which occur in the east central portion of the Ayacucho Basin near the ancient site of Huari. At this point, we do not know whether ancient potters used these sources to obtain materials for producing the Ayacucho pottery which Perlman and Asaro (1969) analyzed. Nevertheless, one can make two generalizations about the area from the present data.
The effect of cell fixation on the discrimination of normal and leukemia cells with laser tweezers Raman spectroscopy.

Laser tweezers Raman spectroscopy (LTRS) was used to characterize the effect of different chemical fixation procedures on the Raman spectra of normal and leukemia cells. Individual unfixed, paraformaldehyde-fixed, and methanol-fixed normal and transformed lymphocytes from three different cell lines were analyzed with LTRS. When compared to the spectra of unfixed cells, the fixed cell spectra show clear, reproducible changes in the intensity of specific Raman markers commonly assigned to DNA, RNA, protein, and lipid vibrations (e.g. 785, 1230, 1305, 1660 cm−1) in mammalian cells, many of which are important markers that have been used to discriminate between normal and cancer lymphocytes. Statistical analyses of the Raman data and classification using principal component analysis and linear discriminant analysis indicate that methanol fixation induces a greater change in the Raman spectra than paraformaldehyde. In addition, we demonstrate that the spectral changes as a result of the fixation process have an adverse effect on the accurate Raman discrimination of the normal and cancer cells. The spectral artifacts created by the use of fixatives indicate that the method of cell preparation is an important parameter to consider when applying Raman spectroscopy to characterize, image, or differentiate between different fixed cell samples to avoid potential misinterpretation of the data. © 2008 Wiley Periodicals, Inc. Biopolymers 91: 132–139, 2009. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Investigation of Practical Routes for the Kilogram-Scale Production of cis-3-Methylamino-4-methylpiperidines

Two routes for the synthesis of cis-N-protected-3-methylamino-4-methylpiperidine (3) were examined: a route hinging on the electrochemical oxidation of carbamate 1 to install a ketone at the 3 position of the piperidine followed by reductive amination (disconnection A), and a route involving the hydrogenation of an appropriately functionalized pyridine (disconnection B). While both routes to the desired compound were ultimately successful, the pyridine hydrogenation approach proved to be more amenable to kilogram-scale preparations due to the crystallinity and purity of intermediates in that route.
Sex differences and the effect of hormonal therapy on ischemic brain injury

Epidemiological data emphasize the importance of sex differences in the mortality and morbidity of stroke and cardiovascular disease. The importance of hormonal influences on stroke outcome has pointed out the importance of gender, age, and presence of neural hormones. This clinical data has been substantiated by various experimental studies using clinically relevant models of cerebral ischemia and stroke. Published findings emphasize that male and female animals respond differently to periods of cerebral ischemia and that various combinations of hormonal treatments can provide protection, both histopathological and behavioral. Mechanisms underlying the hormonal effects on ischemic outcome are multifactorial. These include effects on vascular integrity and cerebral blood flow, excitotoxicity, oxidation pathways, inflammation, and apoptosis. Although many studies have shown positive results with hormonal treatments, negative findings have also been presented. Explanations for the limitations of hormonal treatment include uncertainties regarding therapeutic window, specific therapeutic dose range, as well as the specific pathophysiological processes being targeted. Additional studies are therefore required to clarify under what conditions hormonal therapy is most protective or not warranted. Experimental studies utilizing a variety of cerebral ischemia and stroke models are reviewed to indicate under what conditions sex differences and hormonal therapy are most important in terms of functional outcome.
Increased Abdominal Girth Following Voiding Cystourethrography

A newborn develops increased abdominal girth and mild respiratory distress after undergoing voiding cystourethrography because of bilateral hydronephrosis. ### Prenatal History ### Birth History ### Physical Examination ### Diagnostic Studies Fig 1. Renal ultrasonographic longitudinal view of the right kidney shows dilated calyces (arrows) and a mild amount of fluid in the perinephric space (arrowhead). Parenchymal echogenicity is preserved. Fig 2. Voiding cystourethrography on focalized frontal view demonstrates significant ureteral and pyelocalyceal dilation. The …
The sievert integral revisited: Evaluation and extension to125I, 169Yb, and 192Ir brachytherapy sources

Abstract Purpose: The goal of this study is to assess the accuracy of the Sievert integral dose calculation model for medium and low-energy brachytherapy sources (photon energy: 25–500 keV). A simple modification of the basic model, the isotropic scattering correction, is proposed that significantly improves its accuracy. Methods and Materials: Both the classical and revised Sievert algorithms were tested against 2D dose distributions derived from Monte Carlo photon transport (MCPT) calculations for the following sources: a 169Yb interstitial source, pulsed and high dose rate 192Ir sources and the model 6702 125I source. The Sievert model was implemented as a 3D numerical integral over the radioactivity distribution and included photon attenuation and scattering by the surrounding medium. The Sievert filtration coefficients were approximated by linear energy absorption coefficients, parameters of best fit, and curve fit, and curve fits to simulated open-air transmission measurements. The revised model consists of using the Sievert integral only to calculate the primary dose distribution using contact absorber filtration coefficients. The dose component due to photon scattering in the medium is assumed to be isotropically distributed and is modeled by point-source scatter-to-primary dose ratios. Results: The classical Sievert integral produces maximum and RMS average dose-calculation errors ranging from −53 to −20% and 3 to 19%, respectively. In contrast, the revised model reproduces the MCPT dose distribution with maximum and RMS mean errors ranging frmo 5 to 13% and 1 to 6%, respectively. Conclusions: The classical Sievert model fails to accurately describe brachytherapy dose distributions around heavily filtered sources emitting photons with average energies of 28 to 400 keV. The revised Sievert model accurately models single-source dose distributions for a wide range of sources, using well-defined filtration coefficients and scatter ratios that can be measured or calculated without knowledge of the final dose distribution. The model is potentially useful as a single-source dose-array generatory for clinical treatment planning in the low energy domain.
Further studies in flood tolerance of Betula papyrifera seedlings

Flooding of soil for 60 days drastically reduced height growth, cambial growth, dry weight increment, and relative growth rate of 150-day-old Betula papyrifera Marsh. seedlings. Comparisons of responses to flooding of 150-day-old and 230-day-old seedlings indicated important differences between the two age classes. Whereas the younger seedlings produced abundant adventitious roots on submerged portions of stems, the older seedlings did not. Flooding also induced much more leaf abscission in the older seedlings. Flooding generally reduced root-shoot ratios of both age classes, largely as a result of inhibition of growth and decay of root systems. However, root-shoot ratios were altered appreciably by formation of adventitious roots in the younger seedlings and by extensive leaf abscission in the older seedlings.
Hallucinogens as a discriminative stimuli: generalization of DOM to a 5-methoxy-N, N-dimethyltryptamine stimulus.

Abstract Hallucinogens (psychotomimetic agents) are capable of producing various discriminative stimuli for animals. Serotonergic involvement has been implicated as playing a role in the behavioral effects elicited by, for example, mescaline and DOM. Because certain tryptamine analogs possess high serotonin (5-HT) receptor binding affinities, it was of interest to examine one of the more potent agents. Employing a standard operant test chamber, six rats were trained to respond under a variable-interval 15-second schedule of sweetened-milk reinforcement. 5-Methoxy-N, N-dimethyltryptamine (5-OMe DMT), which possesses a 5-HT receptor affinity much higher than that of mescaline, but nearly equivalent to that of DOM, was found to serve as a discriminative stimulus. Furthermore, the 5-OMe DMT stimulus could be attenuated by the 5-HT antagonist BC-105. The 5-OMe DMT stimulus generalized with DOM suggesting that these two hallucinogens produce qualitatively similar interoceptive cues in rats.
Solving Algebraic Riccati Equations via Proper Orthogonal Decomposition

Abstract In this paper we present a method to solve algebraic Riccati equations by employing a projection method based on Proper Orthogonal Decomposition. The method only requires simulations of linear systems to compute the solution of a Lyapunov equation. The leading singular vectors are then used to construct a projector which is employed to produce a reduced order system. We compare this approach to an extended Krylov subspace method and a standard Gramian based method.
Effects of fiber coating properties on the crack deflection and penetration in fiber-reinforced ceramic composites

A finite element technique is used to study the effects of coating properties on the deflection and penetration of cracks which terminate perpendicular to the fiber-coating or coating-matrix interfaces. Four types of coatings are considered for the SCS6 (fiber)-Zircon (matrix) composites. The hoop and tangential stresses and the energy release rates are analyzed for the various coatings. The effects of the thickness of coatings on these parameters are also studied. In general, no significant changes are found in stress ratio (ratio of hoop stresses along the crack and at the interface) and energy release rate ratio (ratio of energy release rates for the crack penetration and crack deflection), but the magnitudes of the stresses and energy release change substantially with the change in the coating thickness. Also, the effects of the coating properties on various stresses (except on the crack opening stress at the interface) and energy release rates are found to be the same irrespective of the relative modulus of the fiber and matrix.
Advanced Glycation End Products and Receptors in Fuchs’ Dystrophy Corneas Undergoing Descemet’s Stripping with Endothelial Keratoplasty

Purpose To describe the histopathologic features of Descemet's membrane (DM) obtained from Fuchs' endothelial corneal dystrophy (FECD) corneas undergoing Descemet's stripping with endothelial keratoplasty (DSEK) and to assess the presence of advanced glycation end products (AGEs) and their receptors in FECD endothelium and DM. Design Prospective observational case series. Participants Five eyes of 5 patients undergoing DSEK for FECD and 4 normal control eyebank corneas. Methods Descemet's membrane and corneal endothelium from FECD patients undergoing DSEK were assessed with hematoxylin–eosin staining and immunohistochemistry for AGEs, receptor of AGEs (RAGE), and galectin 3 (AGE-R3). Main Outcome Measures Histopathologic abnormalities and presence of AGEs, RAGE, and AGE-R3 in DSEK specimens. Results Histopathologic assessment of DSEK specimens from FECD patients disclosed thickening and nodularity of DM and loss of endothelial cells. Immunohistochemical staining of FECD DM for AGE, RAGE, and AGE-R3 showed an abundance of AGEs in the anterior portion of DM, mild positivity for RAGE, and moderate positivity for AGE-R3. Conclusions Tissue quality after DSEK is sufficient to allow detailed histopathologic analysis. The presence of AGEs, RAGE, and AGE-R3 in DM and corneal endothelium of FECD patients supports a link between accumulation of AGEs, oxidative stress, and corneal endothelial cell apoptosis in the pathogenesis of FECD.