cssi/SciSciGPT-SciSciNet huggingface dataset:
Bill Color Preferences of Zebra Finches

Bill color varies with age and sex in zebra finches. Among birds of similar age and condition, males' bills tend to be redder and darker than those of females, but there is overlap in the phenotypic expression of the sexes. The bills of young birds are paler and less red than those of older birds. There is also interindividual variation within age and sex class. Experiments were performed to measure heterosexual and isosexual (= same sex) preferences of finches. Females preferred to associate with males with the reddest, brightest bills; they even preferred males whose bills were exaggerated through color applications of non-toxic marking pen. Males preferred to associate with females with bill colors in the middle of the phenotypic range. Females thus have “directional” preferences for male bill color, whereas male preference is “stabilizing” with regard to female bill color. In isosexual tests, neither sex showed a consistent preference for particular bill colors. Both sexes, however, displayed a tendency toward individual variability in preference. Bill color appears to be more important in heterosexual than in isosexual interactions. Several authors have recently suggested that organisms prefer brightly colored mates because bright coloration indicates superior physical condition. Results reported here do not support this hypothesis. Alternative functional explanations for the observed preferences are that bill color signals mating status, age or reproductive value. None of these appears to be a cogent explanation for the trends. Preferences do not appear to result from sexual imprinting. The possibility that the preferences are aesthetic and non-functional is discussed.
A simple, predictable intraoral technique for retentive mechanism attachment of implant overdenture attachments

A technique is presented for intraorally attaching two O-ring attachments to a mandibular complete denture. The technique involves fabricating and placing a mandibular denture with conventional procedures. Patients adapt initially to the complete denture. The attachments are then attached to the denture base with autopolymerizing acrylic resin. This technique provides a predictable method to achieve a tissue-supported and implant-retained overdenture.
Racial differences in the association of insulin-like growth factor pathway and colorectal adenoma risk

Purpose Insulin resistance is believed to play an important role in the link between energy imbalance and colon carcinogenesis. Emerging evidence suggests that there are substantial racial differences in genetic and anthropometric influences on insulin-like growth factors (IGFs); however, few studies have examined racial differences in the associations of IGFs and colorectal adenoma, precursor lesions of colon cancer.
Field evaluation of particulate matter measurements using tapered element oscillating microbalance in a layer house

The tapered element oscillating microbalance (TEOM) is one type of continuous ambient particulate matter (PM) monitor. Adsorption and desorption of moisture and semivolatile species may cause positive or negative artifacts in TEOM PM mass measurement. The objective of this field study was to investigate possible uncertainties associated with TEOM measurements in the poultry operation environment. For comparisons of TEOM with filter-based gravimetric method, four instruments (TEOM-PM10, low-volume PM10 sampler TEOM-PM2.5, and PM2.5 speciation sampler) were collocated and tested inside a poultry house for PM2.5 and PM10 (PM with aerodynamic equivalent diameter < or =2.5 and < or =10 microm, respectively) measurements. Fifteen sets of 24-hr PM10 concentrations and 13 sets of 24-hr PM2.5 measurements were obtained. Results indicate that compared with filter-based gravimetric method, TEOM gave significantly lower values of both PM10 and PM2.5 mass concentrations. For PM10, the average ratio of TEOM to the gravimetric method was 0.936. For PM2.5, the average ratio of TEOM to the gravimetric method was 0.738. Particulate matter in the poultry houses possibly contains semivolatile compounds and moisture due to high levels of relative humidity (RH) and gas pollutants. The internal heating mechanism of the TEOM may cause losses in mass through volatilization. To investigate the effects of TEOM settings on concentration measurements, the heaters of two identical TEOMs were set at 50 degrees C, 30 degrees C, or no heating at all. They were collocated and tested for total suspended particle (TSP), PM10, and PM25 measurements in layer house for 6 weeks. For all TSR PM10, and PM2.5 measurements, the internal TEOM temperature setting had a significant effect (P < 0.05). Significantly higher PM mass concentrations were measured at lower temperature settings. The effects of environmental (i.e., temperature, RH, NH3 and CO2 concentrations) and instrumental (i.e., filter loading and noise) parameters on PM measurements were also assessed using regression analysis.
Study of turbulence on supersonic compression surfaces using Reynolds stress model

A theoretical study was conducted to determine the effects of adverse pressure gradient and compressibility in modeling turbulent compressible flows. The zero equation, kinetic-energy/dissipation eddy-viscosity models, and Reynolds stress model predictions are presented and compared with experimental data. It is shown that the effects of compressibility, which include the mass-averaged fluctuation term u j '', the pressure-dilatation term p'∂u l ''/∂x l , and the dilatation dissipation μ(∂u l ''/∂x l ) 2 /p, are important in modeling turbulent compressible flows
Determination of tissue α-tocopherol in senescence-accelerated mice by high-performance liquid chromatography with fluorimetric detection.

Abstract α-Tocopherol (α-Toc) plays an important role in various distinct physiological functions. A convenient assay using high-performance liquid chromatography with fluorimetric detection (the excitation and emission wavelength was 296 and 340 nm, respectively) was developed for the accurate determination of the α-Toc in biological samples. Methanol (1/7; v/v) was used to extract α-Toc in tissue samples by precipitating the proteins. The assay obtained a recovery rate between 97.3 and 104.2% by adding pure α-Toc to mice liver homogenate. The R.S.D. for intra-day ( n =7) and inter-day ( n =6, three consecutive days) analysis was 0.7–2.8 and 0.5–3.7%, respectively. The effect of age on the α-Toc levels in the liver, brain and heart homogenates of senescence-accelerated mice (SAM) was also studied. The α-Toc levels in the tissue homogenates increased gradually with age for both male and female mice, while the female had higher α-Toc levels than the males of the same age.
A portfolio analysis of crop diversification and risk in the cotton south

Abstract Scholars have long been aware of the influence of risk on the behavior of farmers.1 Recently, several econometric historians have studied the influence of risk on the behavior of farmers in the postbellum South ( Reid, 1973 ; Higgs, 1973 , Higgs, 1974 ; Wright and Kunreuther, 1975 , Wright and Kunreuther, 1977 ; McGuire and Higgs, 1977 ). The most recent contributions to this literature analyze the choice between cotton acreage and corn acreage ( Wright and Kunreuther, 1975 , Wright and Kunreuther, 1977 ; McGuire and Higgs, 1977 ). Several controversies discussed in those articles have not been resolved. Those controversies concern, for example, whether cotton or corn was the riskier crop in the late 1800s, whether postbellum Southern farmers displayed risk-averting or risk-taking behavior, and whether data and methods employed to analyze acreage management decisions are appropriate. Those controversies are the central concerns of this paper.
Spontaneous reductions in smoking during double-blind buprenorphine detoxification.

Abstract Objective Evidence suggests a positive association between administration of psychoactive drugs and rates of cigarette smoking. Prevalence of smoking among opioid-dependent individuals, for example, is four times greater than the general population. We recently completed a randomized double-blind trial evaluating outpatient buprenorphine taper for prescription opioid (PO) abusers, which provided a unique opportunity to examine naturalistic changes in smoking among participants who detoxified without resumption of illicit opioid use. Method Participants received no smoking-cessation services and were not encouraged to alter their smoking in any way. A subset of 10 opioid-dependent smokers, who were randomized to receive the same 4-week buprenorphine taper and successfully completed detoxification, were included in the present study. They provided staff-observed urine specimens thrice-weekly throughout the 12-week trial. Specimens were analyzed onsite via enzyme-multiplied immunoassay for urinary cotinine, a metabolite of nicotine that provides a sensitive biochemical measure of smoking status. Results Mean cotinine levels were significantly different across study phases, with significantly lower cotinine levels during taper (1317.5 ng/ml) and post-taper (1015.8 ng/ml) vs. intake (1648.5 ng/ml) phases (p’'s Conclusions These data provide additional evidence that opioids influence smoking and extend prior findings to include primary PO abusers, rigorous double-blind opioid dosing conditions and urinary cotinine. These results also suggest that, while likely insufficient for complete cessation, patients who successfully taper from opioids may also experience concurrent reductions in smoking and thus may be ideal candidates for smoking cessation services.
Technical perspective They do click, don't they?

This is a fascinating piece of work. Not only does it help debunk some unscientific claims related to the underground economy, but also, and more importantly, it is very likely to become a seminal reference for a new area of research.
Assessment of Sediment Quality in Dredged and Undredged Areas of the Trenton Channel of the Detroit River, Michigan USA, using the Sediment Quality Triad

The “sediment quality triad” approach was used to assess the effects of dredging on the sediment quality of a new marina in the Trenton Channel of the Detroit River, and to evaluate spatial and temporal variation in sediment quality in the Trenton Channel. Samples were collected in November of 1993 (10 months after dredging) and characterized by chemical analysis, sediment bioassays, and assessment of benthic invertebrate communities. The three study components indicated little difference in sediment quality at dredged sites in the marina relative to nearby areas in the Trenton Channel, and little change in sediment quality of Trenton Channel sites relative to conditions reported in the mid-1980s. These results suggest that improvement in sediment quality in the Trenton Channel, due to dredging or natural processes, will depend on elimination of sediment “hot spots” and other upstream contaminant sources. Concentrations of chemical contaminants, especially metals and polycyclic aromatic hydrocarbons, exceeded concentrations associated with effects on biota and were significantly correlated with results of sediment bioassays and characteristics of benthic communities. Laboratory sediment bioassays with Hyalella azteca and Chironomus tentans produced better discrimination among sites with differing degrees of contamination than did characterization of benthic communities, which were dominated by oligochaetes at all sites in the marina and the Trenton Channel.
Interfacial studies of carbon-carbon composites

Abstract A detailed study of the microstructure of carbon-carbon composite was performed using transmission electron microscopy (TEM) techniques. Structural characterization is essential in order to fully understand the mechanical and physical properties of carbon-carbon composites. Thin samples of both transverse and longitudinal sections were prepared by using an ion-mill technique. An emphasis was placed on the interfaces between the fiber and the matrix in both longitudinal and transverse section. Bright field micrographs revealed different types of morphology existing within a complex 3D carbon-carbon composite. Dark field micrographs were used to analyze the crystallite size and orientation. Selected-area diffraction (SAD) and convergent-beam electron diffraction (CBED) were used to characterize the microstructure in terms of four parameters: preferred orientation parameter Z , stack height L c , stack width L a , and d 002 spacing. Interfacial analysis showed a very complex interphase between the matrix and the fibers with entirely distinctive microstructural properties.
Shell Thickness as Related to “Shuck-Outs” in Turkey Eggs

ABSTRACT IT IS well known that many turkey embryos fully develop and the poults pip the shell but are unable to emerge on the 28th day of incubation without assistance. These are frequently “shucked-out” and after removal from the incubator they usually develop into normal-appearing birds although they are designated as seconds. An earlier study of this subject, Payne, Ortman and Siegel (1957) showed no significant difference between the time of detection of fertility and the incidence of “shuck-outs.” It occurred to the authors that shell thickness might be associated with this condition. Do the eggs with thin and medium shell thickness provide fewer or more “shuck-outs” than those with thick shells? Mussehl and Halbersleben (1923) studied specific gravity with chicken eggs and its relation to fertility, hatchability and growth of chicks. They found a low positive correlation, r=0.204±0.023 between specific gravity and hatchability of eggs. There was no relationship between . . .
Are fern stomatal responses to different stimuli coordinated? Testing responses to light, vapor pressure deficit, and CO2 for diverse species grown under contrasting irradiances

Summary The stomatal behavior of ferns provides an excellent system for disentangling responses to different environmental signals, which balance carbon gain against water loss. Here, we measured responses of stomatal conductance (gs) to irradiance, CO2, and vapor pressure deficit (VPD) for 13 phylogenetically diverse species native to open and shaded habitats, grown under high- and low-irradiance treatments. We tested two main hypotheses: that plants adapted and grown in high-irradiance environments would have greater responsiveness to all stimuli given higher flux rates; and that species' responsiveness to different factors would be correlated because of the relative simplicity of fern stomatal control. We found that species with higher light-saturated gs had larger responses, and that plants grown under high irradiance were more responsive to all stimuli. Open habitat species showed greater responsiveness to irradiance and CO2, but lower responsiveness to VPD; a case of plasticity and adaptation tending in different directions. Responses of gs to irradiance and VPD were positively correlated across species, but CO2 responses were independent and highly variable. The novel finding of correlations among stomatal responses to different stimuli suggests coordination of hydraulic and photosynthetic signaling networks modulating fern stomatal responses, which show distinct optimization at growth and evolutionary time-scales.
Visual servoing and CAD-driven microassembly

The authors describe current research and development on a robotic visual servoing system for assembly of LIGA (lithography galvonoforming abforming) parts. The workcell consists of an AMTI robot, precision stage, long working distance microscope, and LIGA fabricated tweezers for picking up the parts. Fourier optics methods are used to generate synthetic microscope images from CAD drawings. These synthetic images are used off-line to test image processing routines under varying magnifications and depths of field. They also provide reference image features which are used to visually servo the part to the desired position. Currently, we can visually servo a 100 micron outside diameter LIGA gear to a desired x,y reference position as determined from a synthetic image of the gear.
Tailoring TiO2 nanotube growth during anodic oxidation by crystallographic orientation of Ti

TiO 2 nanotubes exhibit remarkable photoelectrochemical, gas sensing and biological properties. Here we show that TiO 2 nanotube growth can be tailored by the intrinsic crystallographic orientation of the Ti substrate. This finding presents an exciting new approach for tailoring and controlling the rate of nanotube formation by crystallographic manipulation and modification of the Ti surface.
Modifying the acoustic impedance of polyurea-based composites

Acoustic impedance is a material property that depends on mass density and acoustic wave speed. An impedance mismatch between two media leads to the partial reflection of an acoustic wave sent from one medium to another. Active sonar is one example of a useful application of this phenomenon, where reflected and scattered acoustic waves enable the detection of objects. If the impedance of an object is matched to that of the surrounding medium, however, the object may be hidden from observation (at least directly) by sonar. In this study, polyurea composites are developed to facilitate such impedance matching. Polyurea is used due to its excellent blast-mitigating properties, easy casting, corrosion protection, abrasion resistance, and various uses in current military technology. Since pure polyurea has impedance higher than that of water (the current medium of interest), low mass density phenolic microballoon particles are added to create composite materials with reduced effective impedances. The volume fraction of particles is varied to study the effect of filler quantity on the acoustic impedance of the resulting composite. The composites are experimentally characterized via ultrasonic measurements. Computational models based on the method of dilute-randomly-distributed inclusions are developed and compared with the experimental results. These experiments and models will facilitate the design of new elastomeric composites with desirable acoustic impedances.
Methods for quantitative analysis in secondary ion mass spectrometry

Methods for quantitative analysis in secondary ion mass spectrometry must be capable of correcting for strong matrix effects on emitted secondary ion intensities as well as strong instrumental effects on measured secondary ion intensities. Both empirical methods, based on sensitivity factors and working curves, and theoretical models for secondary ion emission, are available. Absolute sensitivity factors are not satisfactory because of the lack of compensation for matrix effects. Working curves are capable of yielding analysis with 5% relative accuracy but offer poor flexibility in dealing with unknowns which differ strongly from the standards. Relative sensitivity factors offer both flexibility in the analysis of unknowns and an error distribution in which 80% of the analyses fall within a factor of 2 of the unknown and 99% within a factor of 5. Numerous physical models for secondary ion emission are available but are generally limited in application due to uncertainties in the required physical data. The local thermal equilibrium (LTE) model is broadly applicable with partial constraint on the composition of the unknown. The LTE error distribution places about 50% of the analyses within a factor of 2 and 80% within a factor of 5. Large errors, exceeding a factor of 10, are observed for heavy elements, possibly due to uncorrected instrument effects. Future development of analytical methods may combine the relative sensitivity factor method (which minimizes the influence of instrument artifacts) with the theoretical description of secondary ion emission (to calculate matrix effects).
Pain in Amyotrophic Lateral Sclerosis: A Neglected Aspect of Disease

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder marked by progressive loss of motor neurons, muscle wasting, and respiratory dysfunction. With disease progression, secondary symptoms arise creating new problematic conditions for ALS patients. Amongst these is pain. Although not a primary consequence of disease, pain occurs in a substantial number of individuals. Yet, studies investigating its pathomechanistic properties in the ALS patient are lacking. Therefore, more exploratory efforts into its scope, severity, impact, and treatment should be initiated. Several studies investigating the use of Clostridial neurotoxins for the reduction of pain in ALS patients suggest the potential for a neural specific approach involving focal drug delivery. Gene therapy represents a way to accomplish this. Therefore, the use of viral vectors to express transgenes that modulate the nociceptive cascade could prove to be an effective way to achieve meaningful benefit in conditions of pain in ALS.
Therapeutic controversies: clinical treatment of benign prostatic hyperplasia.

Benign prostatic hypertrophy (BPH) is the commonest clinical disorder in males over 55 yr of age in the U.S.A. Approximately two thirds of men above 55 will have some symptoms of prostatism due to BPH. Symptoms of prostatism related to BPH result from two major causes. The first and most important of these is the growth of the prostate gland with development of a periurethral adenoma, which compresses the urethra, resulting in obstruction to flow of urine from the bladder. In addition, increased smooth muscle tone of the bladder neck and the prostate itself, which is regulated by cY,-adrenergic receptors, may interfere with emptying of the bladder.
Code scheduling for multiple instruction stream architectures

Extensive research has been done on extracting parallelism from single instruction stream processors. This paper presents our investigation into ways to modify MIMD architectures to allow them to extract the instruction level parallelism achieved by current superscalar and VLIW machines. A new architecture is proposed which utilizes the advantages of a multiple instruction stream design while addressing some of the limitations that have prevented MIMD architectures from performing ILP operation. A new code scheduling mechanism is described to support this new architecture by partitioning instructions across multiple processing elements in order to exploit this level of parallelism.
The efficacy and safety of oral pentobarbital sedation in pediatric echocardiography.

Background Because patient movement during echocardiography interferes with diagnostic quality, many institutions sedate children who are unable to cooperate. The purpose of this review was to determine the efficacy and safety of oral pentobarbital for sedation during pediatric transthoracic echocardiography. Methods Echocardiography laboratory quality assurance data were recorded for 12 years. Sedation data included adverse events, dosing, and failed sedation. The study population was grouped by age: neonates ( Results A total of 9796 patients underwent sedation by oral pentobarbital. The overall sedation success rate was 98.7%, and 99% of these patients remained sedated long enough for study. The overall adverse event rate was 0.5%. Second doses, failed sedation, and adverse events were more common in the young children. Conclusion Oral pentobarbital is an effective and safe sedative for pediatric transthoracic echocardiography. Because of decreased efficacy and an increased incidence of adverse events, alternative sedation strategies may be beneficial in children aged 1 to 4 years.
MicroRNA-34a regulates diabetes-induced impaired angiogenesis: Role of SIRT1

Background: Diabetes, characterized by chronic elevation of blood glucose levels, is associated with impaired angiogenesis, vascular dysfunction and a higher risk of cardiovascular diseases (CVD). Recently, a novel class of small non-coding RNAs (miRNAs, single-stranded RNA molecules comprising 21-23 nucleotides in length) has been identified as important transcriptional/posttranscriptional regulators of gene expression and plays a critical role in the control of most biological processes, including cell differentiation and proliferation, migration, development, and apoptosis. In most cases, miRNAs function as translational repressors and/or activators that exert their action by partially pairing to one or more sequences in the 3'- un-translational regions (3'-UTRs) of target mRNA. Sirtuin-1 (SIRT1), NAD+-dependent deacetylase, has emerged as an important therapeutic target as it regulates various genes involved in endothelial differentiation, proliferation and angiogenesis. In-silico analysis supports the hypothesis that SIRT1 is a potential target of endothelial specific miRNAs. miR-34a has been recently found to target SIRT1 and reported to be critically involved in angiogenesis. In this study, we have investigated whether miR-34a regulates diabetes-induced impaired angiogenesis by targeting SIRT1 in mouse microvascular endothelial cells (MMECs). Results: Real-time PCR analysis reveals that exposure of MMECs to high glucose (HG) results in a significant increase in miR-34a expression and this induction paralleled and correlated with altered expression of SIRT1, eNOS (phospho/acetylation), makers of angiogenesis (VEGF, Ang-1, Ang-2, TSP-1) as well as a significant impairment of tube-forming activity. Interestingly, inhibition of miR-34a increased SIRT1 expression and attenuated changes in downstream signaling and impaired angiogenesis in HG-exposed MMECs. Conclusion: miR-34a, via the regulation of SIRT1 expression, has an anti-angiogenic action in microvascular endothelial cells. Thus, miR-34a may represent a new therapeutic target for the prevention/treatment of diabetic vascular disease and provide a potential miRNA-based mechanism for the regulation of angiogenesis. The project is supported by UREP 13-116-3-024
How does it STAC up? Revisiting the scaffolding theory of aging and cognition.

“The Scaffolding Theory of Aging and Cognition (STAC)”, proposed in 2009, is a conceptual model of cognitive aging that integrated evidence from structural and functional neuroimaging to explain how the combined effects of adverse and compensatory neural processes produce varying levels of cognitive function. The model made clear and testable predictions about how different brain variables, both structural and functional, were related to cognitive function, focusing on the core construct of compensatory scaffolding. The present paper provides a revised model that integrates new evidence about the aging brain that has emerged since STAC was published 5 years ago. Unlike the original STAC model, STAC-r incorporates life-course factors that serve to enhance or deplete neural resources, thereby influencing the developmental course of brain structure and function, as well as cognition, over time. Life-course factors also influence compensatory processes that are engaged to meet cognitive challenge, and to ameliorate the adverse effects of structural and functional decline. The revised model is discussed in relation to recent lifespan and longitudinal data as well as emerging evidence about the effects of training interventions. STAC-r goes beyond the previous model by combining a life-span approach with a life-course approach to understand and predict cognitive status and rate of cognitive change over time.
Macroscopic description of isoscalar giant multipole resonances

We correct two mistakes that cancel each other in our previous derivation of a macroscopic expression for the isoscalar giant-resonance energy as a function of mass number and multipole degree, as well as discuss four additional effects that influence the energy.
The Role of the Carboxy Terminus of Tropoelastin in its Assembly into the Elastic Fiber

A tribute to Dr. Ines Mandl by Carl Franzblau This article is dedicated to the 80th birthday of Dr. Ines Mandl, who for many years was a colleague of ours in the elastin world. My immediate recollection of the younger Ines is a bubbly, vibrant scientist full of enthusiasm and ideas. She was quick on her feet and willing to collaborate and cooperate. Her contributions to our understanding of elastases, collagenases and the respective proteins they digest were immense. Our group is always referring to critical publications that she and her colleagues at Columbia University have published. The field of connective tissue has come a long way, and in no small part it is due to the contributions of our colleague, Ines Mandl.Tropoelastin, the soluble precursor protein of insoluble amorphous elastin, contains repeating segments that are important for the characteristic elasticity and crosslinking sites of mature elastin. In addition, there is a unique carboxy terminal domain that is encoded by exon 36 of the elast...
Fracture and Creep in an All-Tungsten Divertor for ARIES

The ARIES project is currently proposing an all-tungsten divertor for their tokamak designs. In designing such a component, fracture will be a critical failure mechanism, due to the limited ductili...
Myeloma gets the measles

Co-opting micro-organisms as anticancer agents is not a new concept, with multiple agents investigated since the beginning of the 20th century for their potential to kill tumor cells with some degree of selectivity or to redirect immune responses against malignant cells. Other than the instillation
Rosette-formation with mouse erythrocytes: VI. T, B, and third population lymphoid cells in mycosis fungoides and effect of leukopheresis.

Peripheral blood from 16 patients with mycosis fungoides and two patients with Sezary syndrome was examined for T, B, and third-population (K) cells, using a battery of surface markers. T lymphocytes as determined by spontaneous rosette formation with sheep erythrocytes and third-population cells as determined by the Ripley rosette test were present in normal proportions. Surprisingly, B lymphocytes, as determined by surface immunoglobulin and receptors for mouse erythrocytes, were either lacking or were present in low proportions in some patients. Normal proportions were present in others. Repeat studies of two of three patients lacking B lymphocytes, following treatment, revealed normal or low proportions of B cells. Two patients with mycosis fungoides had increased proportions of "null" cells. Study of lymphoid cell subpopulations before and after leukopheresis in a single patient demonstrated a decrease in T cell proportions associated with a concomitant increase in the proportions of "null" cells following this therapy.
Ethical issues concerning therapeutic studies in inflammatory bowel disease

Physicians often take on responsibilities beyond medical care regarding their patients with ulcerative colitis and Crohn's disease: they serve as the patients' advocates to nonmedical entities and individuals, including insurance companies, schools, employers, companions, and family members. These responsibilities create a more complex relationship between the patient and their IBD physician. In addition, these responsibilities may accentuate ethical issues for the physician who is also engaged in clinical treatment trials for inflammatory bowel disease (IBD). Ethical issues include therapeutic misconception, clinical equipoise, and financial and nonfinancial conflicts of interest. Physicians who refer patients with IBD to enroll in treatment trials, as well as clinician investigators who conduct studies should consider measures to clarify the separation between clinical care and participation in a therapeutic study, and to ensure the ethical treatment of patients. These precautionary measures may include payment of participants to emphasize that the research study is different from clinical care, consent by an investigator other than the treating physician, and care to disclose conflicts of interest to the patient and the medical community in presentations and publications. If the financial conflict is too great, a physician should not participate in the clinical trial.
Forced convection mass transfer: Part I. Effect of turbulence level on mass transfer through boundary layers with a small favorable pressure gradient

The effect of free stream turbulence level on forced convection through laminar and turbulent boundary layers on a flat was studied in a wind tunnel with a small but nonzero favorable pressure gradient by means of the naphthalene sublimation technique. With the small favorable pressure gradient used in this study, the rate of forced convection through laminar boundary layers agreed with Polhausen's theoretical equation for turbulence levels less than 2.8% but increased in a regular fashion for turbulence levels greater than 2.8% and was almost tripled at a free stream turbulence level of 11%. There was no evidence of an interaction between pressure gradient and turbulence level which would produce disproportionate effects on the rate of forced convection through laminar boundary layers. Substantially no effect of turbulence level on forced convection through turbulent boundary layers was observed for turbulence levels up to 7%.
Production of mesons by X-rays.

At the spring, 1949, meeting of the National Academy of Sciences(l) a preliminary account was given of some observations of mesons produced by the 335 Mev x-ray beam from the Berkeley synchrotron. The present paper is a progress report of this work; no claim is made for completeness, but sufficient new data are available to make publication at this time worth while, especially since some of the numerical results given in the earlier report require revision. The x-ray beam, produced by the impact of 335 Mev electrons on a 20 mil thick platinum target, has a width at half maximum of 0.0135 radian (about 1 inch at 6 feet from the target). In all but the earliest experiments the beam was further defined by a 1 inch hole in a lead block, then passed through a piece of carbon which served as the meson source. The x-ray intensity at one meter from the target was about 3500 r per hour (measured behind 1/8 inch of lead) under the best running conditions; the average was about half this. The actual exposures at the carbon meson source (6 feet from the target) ranged from 500 to 2000 r in the later runs.more » Mesons were recorded on Ilford nuclear plates; the highest density of meson endings observed was about 100 per square centimeter in a 100 micron emulsion. In the following sections the experimental conditions and some of the results are described in more detail.« less
Fulminant Idiopathic Intracranial Hypertension

Fulminant idiopathic intracranial hypertension is extremely rare but invariably is associatedwith permanent blindness unless there is prompt intervention. Hypothetically, a rapid increase in pressure in the perineural space around the optic nerve can lead to ischemic opticneuropathyandblindness.1An 18-year-oldoverweightwoman with rapidly progressive visual loss over 4 days (leading to no light perception), nonreactive pupils, binocular abduction deficit suggestiveof sixthnervepalsies,bilateraloptic-discedema(Frisenstage 5),2 and cerebrospinal fluid opening pressure at 600 mm H2O receivedadiagnosisof fulminant idiopathic intracranialhypertension.1 The results of cerebrospinal fluid laboratory studies,magnetic resonance imaging of the brain, and vascular imagingwere normal. Our Figure, AandB, showsmagnetic resonance imagingscansof thepatient’s orbits at the time of presentation. Anemergent,controlled lumbardrainwasput inplace,andtreatment with intravenous methylprednisolone sodium succinate and furosemide was started on the first day. Five days later, her visual acuitywas20/400 inbotheyes, herpapilledema improved, andher abduction deficits resolved. Our Figure, C and D, shows follow-up magnetic resonance imaging scans on day 5. A ventriculoperitoneal shunt was performed for relatively long-term control of cerebrospinal fluidpressure.Onday9, herpapilledema improved toFri-
Anesthesia for noncardiac surgery in infants with hypoplastic left heart syndrome following hemi-fontan operation

S TAGE I PALLIATION (Norwood operation) for neonates with hypoplastic left heart syndrome (HLHS) enables survival to allow these children to ultimately be managed in the same fashion as other patients with univentricular cardiac malformations.’ This operation consists of (1) atria1 septectomy, (2) creation of a “neoaorta” that associates the proximal main pulmonary artery with the aortic arch providing unobstructed blood flow from the right ventricle to the systemic circulation, and (3) placement of a systemic to pulmonary artery shunt. On completion of stage I, both the pulmonary and systemic circulations continue to be supplied from the single ventricle in a parallel fashion. This physiology will ultimately result in morbidity due to chronic ventricular volume overload and to chronic hypoxemia. The ultimate goals are to eliminate the excess volume work and to achieve a systemic arterial oxygen saturation that enables normal growth and development without inducing polycythemia. The Fontan procedure satisfies these objectives by creating a series circulation that requires the singleventricle to pump fully saturated blood only to the systemic circulation as the systemic venous return passes directly through the pulmonary vascular bed.2 When Fontan’s operation was undertaken 12 to 18 months after stage I, a high operative mortality (16% to 40%) occurred.3-5 In many, death was attributed to an abrupt change in ventricular geometry when the volume load imposed on the ventricle returned to normal. Echocardiograms obtained postoperatively when compared with the preoperative study showed a small, thick-walled ventricular cavity with a low diastolic volume. Although systolic shortening appeared normal the ventricular compliance was diminished. The anatomic and physiologic consequences of this sudden reduction in the ventricular volume load are diminishing end-diastolic volume with an apparent increase in wall thickness because the muscle mass does not change as rapidly, and impaired diastolic function of the ventricle leading to increased end-diastolic pressure. The resulting increase in pulmonary venous pressure impedes pulmonary blood flow thereby decreasing systemic output. Retrospective analysis of the data available preoperatively proved insufficient to predict those children who would develop a physiologically important reduction of ventricular compliance associated with rapid contraction of cnddiastolic volume following Fontan’s operation.
Common emitter current gain degradation of silicon NPN transistors

NPN silicon transistors exhibit changes in common emitter current gain when subjected to various aging and environmental treatments, among which are exposure to radiation, effects of processes and gas environment, and voltage and temperature stressing. These changes were studied using a device specified over a large current range. Most of these effects are due to surface states, and can be reversed. The effects of metallic contamination on the surface were studied by preparing special samples of transistors with and without aluminum metallizing and comparing their performance after aging in different ambients under various cycles of exposure and treatment. After the current gain has degraded by particular stress treatments, it can be restored to its original value by heat treatment in specific atmospheres. The time required varies from 1 hour to 2 or 3 days. Furthermore, heat treatment in non-oxidizing ambients can again decrease the current gain. Additional experimental studies demonstrate the effects on current gain of biasing the emitter junction. A model fitting the experimental data is presented. This model discusses the exchange of charge between the oxide surface and the interface between the silicon and the oxide. The role of oxygen ions and metallic ions as the species involved in the charge exchange is postulated and discussed.
Effects of Dexamethasone on the Functional Properties of Cartilage Explants during Long-Term Culture:

BackgroundIntact articular cartilage tissue is used clinically in the form of osteochondral allografts and experimentally as explants in modeling the physiologic behavior of chondrocytes in their native extracellular matrix. Long-term maintenance of allograft tissue is challenging.HypothesisBy carefully modulating the preservation environment, it may be possible to preserve osteochondral allograft tissue over the long term while maintaining its original mechanical and biochemical properties.Study DesignControlled laboratory study.MethodsIn this study, juvenile bovine, mature bovine, and canine cartilage explants were cultured in chemically defined media with or without supplementation of dexamethasone for up to 4 weeks.ResultsThe mechanical properties and biochemical content of juvenile bovine explants cultured in the presence of dexamethasone were significantly enhanced after 2 weeks in culture and remained stable with sustained cell viability thereafter. In contrast, the mechanical properties and bioche...
Improved Lower Bounds for the Capacity of i.i.d. Deletion and Duplication Channels

This paper considers the capacity of binary deletion channels, where bits are deleted independently with probability d. It improves significantly upon the best previous framework used to obtain provable lower bounds on this capacity by utilizing a stronger definition of a typical output from the channel. The new results give the best known provable bounds on the capacity for all values of d. Moreover, the techniques presented here extend to yield lower bounds for channels with certain types of random insertions, namely, duplications, or combinations of duplications and deletions. To demonstrate these techniques in this context, two binary channels are analyzed: a channel where each transmitted bit is copied with probability nu and a channel where each transmitted bit is copied a geometrically distributed number of times.
ENDOTHELIAL CELL REGULATION OF CONTRACTILITY OF THE HEART

Endocardial and coronary vascular endothelial cells release substances that modify the contraction of cardiac myocytes. The major and possibly the sole up-regulating substance is endothelin. Several down-regulating substances are secreted, but none has yet been specifically identified. The relative amounts of up- and down-regulating substances are related to tissue oxygen tension. As pO2 rises, the concentration of up- and down-regulating substances, respectively, increases and decreases. Endothelin increases isometric force and decreases actomyosin ATPase activity thus increasing the economy of conversion of chemical to hydrodynamic energy. Beta-adrenergic agonists increase ATPase activity through an endothelial cell-dependent mechanism, leading to decreased economy. Therefore, two endothelial cell-dependent systems exist for regulating contractile efficiency: One involving endothelin appears to optimize the contraction for efficiency; the other, the beta-adrenergic-mediated system, optimizes for power.
Enhanced Potency of a Broadly Neutralizing HIV-1 Antibody In Vitro Improves Protection against Lentiviral Infection In Vivo

Over the past 5 years, a new generation of highly potent and broadly neutralizing HIV-1 antibodies has been identified. These antibodies can protect against lentiviral infection in nonhuman primates (NHPs), suggesting that passive antibody transfer would prevent HIV-1 transmission in humans. To increase the protective efficacy of such monoclonal antibodies, we employed next-generation sequencing, computational bioinformatics, and structure-guided design to enhance the neutralization potency and breadth of VRC01, an antibody that targets the CD4 binding site of the HIV-1 envelope. One variant, VRC07-523, was 5- to 8-fold more potent than VRC01, neutralized 96% of viruses tested, and displayed minimal autoreactivity. To compare its protective efficacy to that of VRC01 in vivo, we performed a series of simian-human immunodeficiency virus (SHIV) challenge experiments in nonhuman primates and calculated the doses of VRC07-523 and VRC01 that provide 50% protection (EC 50). VRC07523 prevented infection in NHPs at a 5-fold lower concentration than VRC01. These results suggest that increased neutralization potency in vitro correlates with improved protection against infection in vivo, documenting the improved functional efficacy of VRC07-523 and its potential clinical relevance for protecting against HIV-1 infection in humans. IMPORTANCE IntheabsenceofaneffectiveHIV-1vaccine,alternativestrategiesareneededtoblockHIV-1transmission.Directadministrationof HIV-1-neutralizingantibodiesmaybeabletopreventHIV-1infectionsinhumans.ThisapproachcouldbeespeciallyusefulinindividualsathighriskforcontractingHIV-1andcouldbeusedtogetherwithantiretroviraldrugstopreventinfection.Tooptimizethe chanceofsuccess,suchantibodiescanbemodifiedtoimprovetheirpotency,breadth,andinvivohalf-life.Here,knowledgeofthe structureofapotentneutralizingantibody,VRC01,thattargetstheCD4-bindingsiteoftheHIV-1envelopeproteinwasusedtoengineeranext-generationantibodywith5-to8-foldincreasedpotencyinvitro.Whenadministeredtononhumanprimates,thisantibody conferredprotectionata5-foldlowerconcentrationthantheoriginalantibody.Ourstudiesdemonstrateanimportantcorrelation betweenin vitroassays used to evaluate the therapeutic potential of antibodies and theirin vivoeffectiveness.
Time-domain wave propagation in optical structures

To make time-domain computation more efficient in optical structures, the wave equation is rewritten to track only the envelope of the electric field. The resultant equation is complex in nature and it is solved via a mapping concept and a Pade approximation. Compared to the finite-difference time-domain algorithm, this method takes two orders of magnitude less memory. This method is applied to the propagation of a 500 fsec pulse in a waveguide over 2 mm. Transient behavior and the effects of waveguide parameters are demonstrated. >
Determining mineral weathering rates based on solid and solute weathering gradients and velocities: application to biotite weathering in saprolites

Abstract Chemical weathering gradients are defined by the changes in the measured elemental concentrations in solids and pore waters with depth in soils and regoliths. An increase in the mineral weathering rate increases the change in these concentrations with depth while increases in the weathering velocity decrease the change. The solid-state weathering velocity is the rate at which the weathering front propagates through the regolith and the solute weathering velocity is equivalent to the rate of pore water infiltration. These relationships provide a unifying approach to calculating both solid and solute weathering rates from the respective ratios of the weathering velocities and gradients. Contemporary weathering rates based on solute residence times can be directly compared to long-term past weathering based on changes in regolith composition. Both rates incorporate identical parameters describing mineral abundance, stoichiometry, and surface area. Weathering gradients were used to calculate biotite weathering rates in saprolitic regoliths in the Piedmont of Northern Georgia, USA and in Luquillo Mountains of Puerto Rico. Solid-state weathering gradients for Mg and K at Panola produced reaction rates of 3 to 6×10 −17 mol m −2 s −1 for biotite. Faster weathering rates of 1.8 to 3.6×10 −16 mol m −2 s −1 are calculated based on Mg and K pore water gradients in the Rio Icacos regolith. The relative rates are in agreement with a warmer and wetter tropical climate in Puerto Rico. Both natural rates are three to six orders of magnitude slower than reported experimental rates of biotite weathering.