cssi/SciSciGPT-SciSciNet huggingface dataset:
Linear light source reflectometry

This paper presents a technique for estimating the spatially-varying reflectance properties of a surface based on its appearance during a single pass of a linear light source. By using a linear light rather than a point light source as the illuminant, we are able to reliably observe and estimate the diffuse color, specular color, and specular roughness of each point of the surface. The reflectometry apparatus we use is simple and inexpensive to build, requiring a single direction of motion for the light source and a fixed camera viewpoint. Our model fitting technique first renders a reflectance table of how diffuse and specular reflectance lobes would appear under moving linear light source illumination. Then, for each pixel we compare its series of intensity values to the tabulated reflectance lobes to determine which reflectance model parameters most closely produce the observed reflectance values. Using two passes of the linear light source at different angles, we can also estimate per-pixel surface normals as well as the reflectance parameters. Additionally our system records a per-pixel height map for the object and estimates its per-pixel translucency. We produce real-time renderings of the captured objects using a custom hardware shading algorithm. We apply the technique to a test object exhibiting a variety of materials as well as to an illuminated manuscript with gold lettering. To demonstrate the technique's accuracy, we compare renderings of the captured models to real photographs of the original objects.
A local-structure model for calculation of lattice vibrations in liquid water☆

Abstract The local-structure model of Bryan and Curnutte, which treated a single molecule in a rigid cage, has been extended to include a central water molecule and its four nearest neighbors surrounded by a rigid cage of next-nearest neighbors. The influence of the next-nearest neighbors is accounted for by the average forces they exert on the five-molecule local-structure group. With parameters based on water at 25°C, we give calculations of the spectra of liquid H 2 O and D 2 O at 25°C and for ice I . The results of the calculations are compared with observed spectra and with recent molecular-dynamics calculations.
Composite asymptotic expansions and scaling wall turbulence

In this article, the assumptions and reasoning that yield composite asymptotic expansions for wall turbulence are discussed. Particular attention is paid to the scaling quantities that are used to render the variables non-dimensional and of order one. An asymptotic expansion is proposed for the streamwise Reynolds stress that accounts for the active and inactive turbulence by using different scalings. The idea is tested with the data from the channel flows and appears to have merit.
GLORIA surveys in frontier areas of the southwest Pacific Ocean

In August 1989, a geophysical survey in parts of the Exclusive Economic Zones of Vanuatu, Solomon Islands, Fiji, Tonga, and Western Samoa was conducted using a variety of techniques including GLORIA sidescan sonar, Seabeam wide-swath bathymetry, 3.5-kHz subbottom profiling, and dual-channel seismic reflection profiling. The data obtained are relevant to significant regional geotectonic problems, and their interpretation has helped to clarify some of these problems, identify areas where potential mineral deposits may be expected to occur, and in some cases, where geohazards may exist on the sea floor. The survey is described in this contribution, and the following papers in this special issue interpret the results of this work.
Imaging of laser-induced reactions of individual defect nanoclusters.

The response of individual defect nanoclusters located in the bulk of a dielectric material following exposure to 355-nm, 3-ns high-power laser irradiation is investigated by use of microscopic fluorescence imaging. Experiments were carried out on KH2PO4 crystals. We provide direct imaging of the reaction to an external stimulus of individual defect clusters and demonstrate a novel method of studying the dynamic behavior of bulk defects.
Drought, deluge and declines: the impact of precipitation extremes on amphibians in a changing climate

The Class Amphibia is one of the most severely impacted taxa in an on-going global biodiversity crisis. Because amphibian reproduction is tightly associated with the presence of water, climatic changes that affect water availability pose a particularly menacing threat to both aquatic and terrestrial-breeding amphibians. We explore the impacts that one facet of climate change—that of extreme variation in precipitation—may have on amphibians. This variation is manifested principally as increases in the incidence and severity of both drought and major storm events. We stress the need to consider not only total precipitation amounts but also the pattern and timing of rainfall events. Such rainfall “pulses” are likely to become increasingly more influential on amphibians, especially in relation to seasonal reproduction. Changes in reproductive phenology can strongly influence the outcome of competitive and predatory interactions, thus potentially altering community dynamics in assemblages of co-existing species. We present a conceptual model to illustrate possible landscape and metapopulation consequences of alternative climate change scenarios for pond-breeding amphibians, using the Mole Salamander, Ambystoma talpoideum, as an example. Although amphibians have evolved a variety of life history strategies that enable them to cope with environmental uncertainty, it is unclear whether adaptations can keep pace with the escalating rate of climate change. Climate change, especially in combination with other stressors, is a daunting challenge for the persistence of amphibians and, thus, the conservation of global biodiversity.
Statistical analysis of bernoulli, logistic and tent maps with applications to radar signal design

The uniqueness of the Bernoulli frequency modulated signal, and other chaos-based FM signals, can be exploited to improve the performance of the Synthetic Aperture Radar systems. Recent work 1,2 suggests that the Bernoulli map has an unusual behavior compared to other one dimensional discrete maps, such as Logistic or Tent maps. Additional work3 indicates that the sum of consecutive Bernoulli samples is generally non-Gaussian, except when the map parameters A= 0.5 and B = 1.8. This motivates us to analyze the behavioral differences of the maps for various parameters using the Lyapunov exponent, pseudo-phase spatial trajectory and neighbor samples correlation. Specifically, the correlation of Bernoulli samples is analyzed in terms of the probability density function which is derived from experimental data.. Some of statistical tools used include the Forbenius-Perron Operator, and the correlation properties of chaotic sequences. In addition, other measurements of chaos derived from nonlinear dynamical modeling will be used such as: the Lyapunov exponent and the bifurcation diagram. Results show differences between the calculated features; for example, the Lyapunov exponent is bigger for Bernoulli FM than Logistic or Tent FM. In summary, we determined that Bernoulli FM is more chaotic than Logistic or Tent FM. We have also found another singularity in the correlation of sequence samples for the Bernoulli map.
Developing nurse leaders: a program enhancing staff nurse leadership skills and professionalism

This study aims to determine whether participation in the Nursing Leadership Perspectives Program (NLPP) at Mayo Clinic in Rochester, Minnesota, produced a change in leadership skills, increased professional activities, leadership promotion, and retention rates of participants. The NLPP is an educational program designed to enhance leadership skills and promote professionalism of registered nurses. The 6-month program provides participants with theoretical knowledge, core competencies, and opportunities to practice application of leadership skills. Outcome metrics were collected from registered nurses who completed the program (n = 15). Data analysis included descriptive and nonparametric methods. Participants reported statistically significant changes in their leadership skills after participation in the program (P = .007) on the Leadership Practices Inventory. Changes in professional behavior were also statistically significant as rated by the Nursing Activity Scale (P = .001). Participants demonstrated a change in leadership skills and professional behavior following the program.
Special considerations for functional magnetic resonance imaging of pediatric populations

Functional MRI (fMRI) provides a noninvasive means of studying both typical and atypical brain development in vivo. However, the developmental and clinical status of the populations of interest impact how neuroimaging data should be collected, analyzed, and interpreted. In the present work, we review methodological and theoretical issues relevant to developmental and clinical neuroimaging research and provide possible approaches for addressing each. These issues include accounting for differences in biological noise, neuroanatomy, motion, and task performance. Finally, we emphasize the importance of a converging methods approach in constraining and supporting interpretations of pediatric imaging results.
Enhanced Mortality of Selected Central Nervous System Depressants in Hypoexcretory Mice

The mortality of nine central nervous system depressant drugs was compared in normal and hypoexcretory mice. Anuria was produced in mice by penile ligation; cholestasis was produced by bile duct ligation. The intraperitoneal administration of prochlorperazine, trifluoperazine, perphenazine, meprobamate, and chloral hydrate produced significantly elevated mortality rates in anuric mice whereas promazine, perphenazine, and meprobamate showed elevated mortality rates in cholestatic mice. The mortality of chlorpromazine and phenobarbital was not altered in hypoexcretory mice.
Isosteric regulation of the acetylcholine receptor

Abstract Acetylcholine binding to the acetylcholine receptor initiates three important events in the initiation and regulation of the transmission of signals between nerve cells and between nerve and muscle cells: the opening of transmembrane channels; a conformational change of the receptor resulting in an inactive protein (receptor desensitization); and binding to a regulatory site that inhibits the formation of transmembrane channels. Jayant Udgaonkar and George Hess describe the two regulatory processes mediated by acetylcholine — the interaction of acetylcholine with a recently discovered regulatory site, and receptor desensitization, which does not involve the regulatory site and entails a conformational change of the receptor from an active to an inactive form with different ligand binding properties and which cannot form transmembrane channels.
Simplified neutral atom microscopy

For some decades scientists have been interested the possibility of imaging surfaces using a focused beam of neutrally charged atoms or molecules. Scattering of neutral atoms provides a low-energy, surface-sensitive probe, and imaging with this could result in new insights. However, it has been difficult to form a sharply focused and sufficiently intense beam of neutral particles. The first image from such a microscope was published in 2008. We have succeeded with a new approach, using pinhole optics and a mechanically scanned sample. Resolution has reached 3 µm. Recent images and design theory are presented.
Symbolic Program Analysis Using Term Rewriting and Generalization

Symbolic execution by James C. King (1976) is a popular program verification technique, where the program inputs are initialized to unknown symbolic values, and then propagated along program paths with the help of decision procedures. This technique has two main bottlenecks: (a) the number of program execution paths to be explored may be exponential, and, (b) the state representation (map from variables to terms) may blow-up. We propose a new program verification technique that addresses the problems by (a) performing a work list based analysis that handles join points, and (b) simplifying the intermediate state representation by using term rewriting. In addition, our technique tries to compact expressions generated during analysis of program loops by using a term generalization technique based on anti-unification. We have implemented the proposed method in the F-SOFT verification framework using the Maude term rewriting engine. Preliminary experiments show that the proposed method is effective in improving verification times on real-life benchmarks.
Harmonic load identification and determination of load composition using a least squares method

Abstract Presently, the process of harmonic load identification is limited to identification of one load at a time since it uses measurements of voltage and current at that load bus. Given measurements of the current at any load bus that has one or more loads attached at that bus, this paper addresses two issues. First, a simple method for identifying different types of loads on line is described. Second, a quantitative metric that describes the contribution of each individual load type to the total load at that bus is developed (load composition). A least squares algorithm is then used to perform the task of correctly identifying different load types on line and to obtain a value for the metric that describes the individual contribution of each load type to the total load seen at that bus. This concept of harmonic load identification can naturally be extended to include the case of using substation measurements.
Outcomes of a Third Bariatric Procedure for Inadequate Weight Loss

Background and Objectives: The robust volume of bariatric surgical procedures has led to significant numbers of patients requiring reoperative surgery because of undesirable results from primary operations. The aim of this study was to assess the feasibility, safety, and outcomes of the third bariatric procedure after previous attempts resulted in inadequate results. Methods: We retrospectively identified patients who underwent a third bariatric procedure for inadequate weight loss or significant weight regain after the second operation. Data were analyzed to establish patient demographic characteristics, perioperative parameters, and postoperative outcomes. Results: A total of 12 patients were identified. Before the first, second, and third procedures, patients had a mean body mass index of 67.1 29.3 kg/m 2 , 60.9 28.3 kg/m 2 , and 49.4 19.8 kg/m 2 , respectively. The third operations (laparoscopic in 10 and open in 2) included Roux-en-Y gastric bypass (n 5), revision of pouch and/or stoma of Roux-en-Y gastric bypass (n 3), limb lengthening after Roux-en-Y gastric bypass (n 3), and sleeve gastrectomy (n 1). We encountered 5 early complications in 4 patients, and early reoperative intervention was needed in 2 patients. At 1-year follow-up, the excess weight loss of the cohort was 49.4% 33.8%. After a mean follow-up time of 43.0 28.6 months, the body mass index of the cohort reached 39.9 20.8 kg/m 2 , which corresponded to a mean excess weight loss of 54.4% 44.0% from the third operation. At the latest follow-up, 64% of patients had excess weight loss 50% and 45% had excess weight loss 80%. Conclusion: Reoperative bariatric surgery can be carried out successfully (often laparoscopically), even after 2 previous weight loss procedures.
Ultrasonic evaluation of fatigue damage in metal matrix composites

Abstract This paper describes an experimental nondestructive technique for fatigue damage assessment in metal matrix composites by measuring ultrasonic phase velocity and attenuation. A [0/90] SiC/Ti15V3Cr3Al3Sn metal matrix composite is considered as a model system. Cyclic loading at 50 and 70% of the ultimate sample strength were used until failure. The ultrasonic phase velocities and attenuations were measured periodically and found to be very sensitive to fatigue damage. The fatigue-induced changes in the composite elastic constants were calculated from the measured ultrasonic velocity data. For samples heat treated prior to fatigue (815°C) above the matrix β transus (about 760°C), the dominant damage mechanism is debonding of the fiber/matrix interface. We found that when samples were fatigued for less than 50% of the lifetime, the reduction of the composite moduli was linearly dependent on the number of fatigue cycles, which is explained by extension of interfacial partial debonds. This was supported by micromechanical analysis based on a partial disbond model. The rate of decrease in the composite moduli in the second half of the fatigue life was found to be lower, which may serve as a basis for estimation of the remaining fatigue life of the composite from ultrasonic velocity and attenuation measurements. The attenuation data was obtained in directions perpendicular to the fiber. A single-fiber scattering model has been used to explain the effect of the fiber/matrix interface on attenuation. Good correlation between attenuation and moduli measurements was observed.
A response adjustment procedure for assessing stimulus preference in preweanlings.

A nonlearned, response-dependent testing technique entitled Response Adjustment Procedure (RAP) is introduced. The technique is designed to circumvent or reduce the use of a learning paradigm in very immature animals and utilizes age and species-appropriate motor behavior. Initial data on the onset of light avoidance in rats are presented to illustrate the method.
Variation in Lymph Node Assessment After Colon Cancer Resection: Patient, Surgeon, Pathologist, or Hospital?

Background Evaluation of ≥12 lymph nodes after colon cancer resection has been adopted as a hospital quality measure, but compliance varies considerably. We sought to quantify relative proportions of the variation in lymph node assessment after colon cancer resection occurring at the patient, surgeon, pathologist, and hospital levels.
Two modes of unsaying in the early thirteenth century Islamic lands: Theorizing apophasis through Maimonides and Ibn 'Arabī

This comparative study juxtaposes two celebrated medieval examples of negative speech, apophasis, and theorizes the languages of unsaying in the great medieval thinkers, Maimonides (d.1204) and Ibn ‘Arabī (d.1240). The paper coins a distinction between ‘asymmetrical’ versus ‘symmetrical’ approaches to language as a heuristic to analyze the two philosophical apophatic accounts comparatively. While apophatic thinkers in Neoplatonic traditions generally oscillate between these two poles in their various apophatic moments, the paper argues that Maimonides and Ibn ‘Arabī represented the climax of these two non-linear poles in a visible tension and conversant with each other. I frame philosophical apophasis in the medieval Islamic lands in terms of the problem of God’s transcendence versus imminence. Maimonides celebrates apophasis and claims that negative speech, asymptotically approaching silence, is the only genuine praise to God. As an uncompromising exponent of absolute transcendence, and a severe critic of those who ascribe attributes to God, he privileges apophasis to kataphasis; he presents negative speech as a medium of purification and spiritual progress. Ibn ‘Arabī, on the other hand, is critical of this widespread asymmetry, and defends the gathering together of transcendence and imminence for human perfection. His intricate theory of transcendence and imminence appeals to a dialectical logic, explaining why kataphasis and apophasis are symmetrical in front of the Absolute. The productive tension between two apophatic minds challenges Hegelian habits of reading the history of thought, as well as various scholarly prejudices about medieval intellectual landscapes.
Single particle dynamics at synchro-betatron coupling resonances

The action-angle variables for the longitudinal motion in synchrotrons are defined to conform with that of the transverse degrees of freedom. The Hamiltonian due to synchro-betatron coupling resonances is formulated in terms of these action-angle variables. A method for the calculation of the synchro-betatron resonance strength is discussed. The dynamics of particle motion near a resonance condition in the presence of nonlinear detuning is studied. The hysteresis phenomena associated with these resonances are discussed and employed to deduce the resonance Hamiltonian from experimental data.
Synthesis and structure―activity relationship of 3β-(4-alkylthio, - methylsulfinyl, and -methylsulfonylphenyl)tropane and 3β-(4-alkylthiophenyl)nortropane derivatives for monoamine transporters

Early studies led to the identification of 3β-(4-methoxyphenyl)tropane-2β-carboxylic acid methyl ester ( 5 ) with high affinity at the DAT (IC 50 = 6.5 nM) and 5-HTT ( K i = 4.3 nM), while having much less affinity at the NET ( K i = 1110 nM). In the present study, we replaced the 4′-methoxy group of the 3β-phenyl ring with a bioisosteric 4′-methylthio group to give 7a . We also synthesized a number of 3β-(4-alkylthiophenyl)tropanes 7b – e , 3β-(4-methylsulfinylphenyl) and 3β-(4-methylsulfonylphenyl)tropane analogues 7f – h as well as the 3β-(4-alkylthiophenyl)nortropane derivatives 8 – 11 to further characterize the structure–activity relationship of this type of compound for binding at monoamine transporters. With exception of the 4′-methylsulfonyl analogue 7h , all the tested compounds possessed high binding affinities at the 5-HTT. The K i values ranged from 0.19 nM to 49 nM. The 3β-(4-methylthiophenyl)tropane 7a and its N -(3-fluoropropyl) analogue 9a and N -allyl analogue 10a are the most selective compounds for the 5-HTT over the NET (NET/5-HTT = 314–364) in the series. However, none of the compounds showed selectivity similar to 5 for both the DAT and 5-HTT relative to the NET. This study provided useful SAR information for rational design of potent and selective monoamine transporter inhibitors.
Rheology and stability of coal—oil and coal—oil—alcohol dispersions

Abstract Studies on the effect of various surfactants on the stability of coal—oil mixtures (COM) have been carried out and a few of them were identified as most effective stabilizing agents. Rheological studies on coal dispersions in hexadecane were undertaken as a model system to elucidate the role of these surfactants on COM stability. Viscosity measurements of COM with various percentages of coal revealed that there is a marked increase in viscosity above 40% of coal concentration. At low concentrations of surfactants ( Fuel oil is highly viscous and requires elevated temperatures to exhibit suitable flow characteristics. Methanol or ethanol was found to be immiscible with the fuel oil used in the present study. However, upon the addition of an appropriate amount of a lower chain hydrocarbon or kerosene, a stable single phase mixed fuel system (fuel oil + alcohol + alkane = alcofuel) was formed. The coal + oil mixtures prepared with alcofuels exhibited much lower viscosity than those prepared with fuel oil No. 6. Both types of COMs showed similar heating values. The advantages of alcofuels as compared to those of conventional fuel oils are emphasized in relation to COM technology.
Estimation of stellar instrument magnitudes

The Attitude Determination System (ADS) aboard Space Station Freedom will utilize star trackers (ST) with CCD optical sensors and inertial sensor assemblies (ISA) with ring laser gyro (RLG) inertial rotation sensors. An on-board star catalog of some 2100 stars, with magnitudes extending up to 5.15 instrument magnitude, will be used in conjunction with the ADS. The catalog contains both stellar inertial position and instrument magnitude data. This paper describes the procedure used to estimate the stellar instrument magnitudes for stars in the catalog, and characterizes the associated errors. Basically, the procedure involves the use of published detailed stellar spectral irradiance data and ST vendor provided optical and CCD spectral responsivity curves to numerically determine the instrument magnitudes of the stars associated with the published data.
Kinetics of carbon nanotube oxidation

Carbon nanotubes, graphite and amorphous carbon are structurally different, which is reflected in their reactivity and the resistance to oxidation. This paper reports the stability of single- and multi-walled nanotubes, and their true oxidation rates based on conversion to CO2 when heated in the presence of oxygen. Non-isothermal techniques were employed to determine the kinetic parameters for the oxidation of nanotubes, amorphous carbon and graphite. Single-walled nanotubes were found to be the most reactive, followed by multi-walled nanotubes, amorphous carbon and graphite. The oxidation rates of different single-walled tubes samples containing different residual catalysts were also found to vary significantly.
I have seen the future: it is flooded with email

I have been using electronic mail for years, first via Bitnet, then via the Internet. What do you do when you get email from someone you know? Delete it? No, of course not. You read it and you answer it. Therein lies my problem. Everyone is answering me! A few months ago, when I logged on, I had five or six messages each day. Now I log on to find 10 or 20 messages, all of them requiring a response. I suppose I could delete them, but friends are hard to find, so I find myself reading and responding to more and more messages-often on subjects I don't really care about. Everyone, it seems, feels it is better to send than to receive. Did Alvin Toffler warn us about this? I have had a vision of the future. In it, we live in a virtual-reality environment and we spend all our waking hours as employees of the US Electronic Postal Service. Wake me when it's over. >
Cluster-model calculations of the electrodisintegration of lithium

Abstract Extending previously derived cluster-model treatments of the lithium isotopes to continuum states, we calculate (longitudinal) electrodisintegration cross-sections in the energy loss range 1.5 to 7.5 MeV, for momentum transfers q 2 = 0 to 1.5 fm −2 .
Theoretical and experimental investigation of electronic structure and relaxation of colloidal nanocrystalline indium phosphide quantum dots

We present results of theoretical studies of the electronic structure, and experimental studies of electronic relaxation dynamics, for colloidally synthesized InP quantum dots (QD's). Detailed theoretical calculations of the electronic structure of a 41.8 \AA{} diameter InP QD, based on an atomistic pseudopotiential approach, are presented and discussed in the context of experimental measurements. Using femtosecond transient absorption (TA) spectroscopy, we find that the rate of relaxation of photogenerated excitons to the lowest-energy exciton level varies depending upon excitation energy and surface chemistry. Etching the QD's passivates surface electron traps and yields enhanced carrier cooling, which we ascribe to improved confinement of charge carriers to the QD core. When exciting near or slightly above the first exciton state, we observe a sub-picosecond decay of the band edge TA bleach signal which we attribute to a thermalization process. We also present size-selective transient absorption measurements providing experimental evidence which confirms the existence of two s-like exciton states spaced by \ensuremath{\sim}100 meV.
Tailoring perfluorosulfonated ionomer-entrapped sol-gel-derived silica nanocomposite for spectroelectrochemical sensing of Re(DMPE)3+

The influence of the initial molar ratio of water relative to tetraethyl orthosilicate (TEOS) precursor and the content of Nafion ionomer in sol-gel-derived silica composites on the voltammetric response of electrodes modified with these composites for [Re I (DMPE) 3 ] + was investigated. The slow diffusion of [Re I -(DMPE) 3 ] + in Nafion can be significantly improved by dispersing Nafion in sol-gel-derived silica, and the diffusion of[Re I (DMPE) 3 ] + in such a composite increases with the increase in water/TEOS molar ratio and the decrease in Nafion content. With the mass ratio ofNafion relative to sol-gel-derived silica being 40:100 and the initial molar ratio of water relative to TEOS being 20:1, the electrodes modified with the derived Nafion-silica nanocomposite exhibited an apparent peak current increase rate, during preconcentration of [Re I (DMPE) 3 ] + , that was approximately three times faster than the corresponding Nafion-modified electrode. Compared with bare indium-tin oxide (ITO) glass, the composite-coated ITO glass showed a 25-fold enhancement in voltammetric response to [Re I (DMPE) 3 ] + . The suitability of the developed optically transparent Nafion-silica composite for spectroelectrochemical sensing of [Re I (DMPE) 3 ] + was demonstrated. The [Re I (DMPE) 3 ] + extracted into the coating (∼0.4 μm in thickness) was electrolyzed to [Re II (DMPE) 3 ] 2+ . Under attenuated total reflection mode, the in-situ electrogenerated chromophore [Re II (DMPE) 3 ] 2+ was monitored by probing its interaction with the evanescent field of light of a selected wavelength. Thus, the elements required for a spectroelectrochemical sensor with three modes of selectivity were demonstrated: partitioning into the film on an electrode surface and an electrochemically modulated optical signal.
Challenges in optimizing isotretinoin use for acne vulgaris.

Acne vulgaris is one of the most common skin disorders affecting adolescents and young adults. Food and Drug Administration approval of isotretinoin in 1982 dramatically changed the management of nodulocystic and severe, recalcitrant acne. Isotretinoin remains the only acne treatment associated with complete remission and �cure� of nodulocystic acne. Yet despite the dramatic effect of the drug, disease relapse can occur after isotretinoin therapy. Multiple treatment algorithms and dosing regimens have been proposed for isotretinoin, and a cumulative dose of 120 to 150 mg/kg is widely accepted as the standard treatment protocol. Alternative strategies have been designed to optimize drug dosing to achieve acceptable clinical results while minimizing adverse effects. Such regimens range from 0.2 mg/kg/d to greater than 2 mg/kg/d of isotretinoin with variations in treatment duration. These differing opinions on the dosing of isotretinoin expose a gap in our medical knowledge about optimal isotretinoin dosing for acne vulgaris.
A key stone cop regulates oxalate homeostasis.

A new study shows that Slc26a6-null mice manifest calcium-oxalate nephrolithiasis accompanied by enhanced net intestinal oxalate absorption. These findings point to a critical role for Slc26a6 in gastrointestinal oxalate secretion and suggest a genetic explanation for a common form of renal stone disease in humans.
Relationship between the potential and actual intensities of tropical cyclones on interannual time scales

[1] The thermodynamic theory for the physics of a mature tropical cyclone (TC) tells us that the cyclone’s intensity cannot exceed an upper bound, the potential intensity (PI). This combined with an empirical result due to Emanuel leads to a prediction of average TC intensity change, given the change in PI. The slope of the predicted relationship between percentagewise variations in PI and those in intensity can vary between 0.5 and 1, depending on the mean PI and on what threshold is applied to the intensity data. For the Atlantic and Pacific, typical values are around 0.65 when tropical storms are excluded and 0.8 when they are included. The authors use best track data for the North Atlantic and western North Pacific, combined with PI computed from reanalysis data sets, to test these predictions. The results show that observed interannual variations of maximum TC intensity are consistent with the predictions of PI theory. Modest fractions of the variance in actual intensity are explained by PI variations. Much of the interannual variation in PI experienced by the storms comes from variation in TC tracks, so that the storms in different years are more or less likely to sample regions of high PI, rather than from variations in PI at a fixed location. Citation: Wing, A. A., A. H. Sobel, and S. J. Camargo (2007), Relationship between the potential and actual intensities of tropical cyclones on interannual time scales, Geophys. Res. Lett., 34, L08810, doi:10.1029/2006GL028581.
Observations of HNO 3 , ΣAN, ΣPN and NO 2 fluxes: evidence for rapid HO x chemistry within a pine forest canopy

Measurements of exchange of reactive nitrogen oxides between the atmosphere and a ponderosa pine forest in the Sierra Nevada Mountains are reported. During winter, we observe upward fluxes of NO 2 , and downward fluxes of total peroxy and peroxy acyl nitrates (ΣPNs), total gas and particle phase alkyl and multifunctional alkyl nitrates (ΣANs (g+p) ), and the sum of gaseous HNO 3 and semi-volatile NO 3 − particles (HNO 3(g+p) ). We use calculations of the vertical profile and flux of NO, partially constrained by observations, to show that net midday ΣNO yi fluxes in winter are –4.9 ppt m s −1 . The signs and magnitudes of these wintertime individual and ΣNO yi fluxes are in the range of prior measurements. In contrast, during summer, we observe downward fluxes only of ΣANs (g+p) , and upward fluxes of HNO 3(g+p) , ΣPNs and NO 2 with signs and magnitudes that are unlike most, if not all, previous observations and analyses of fluxes of individual nitrogen oxides. The results imply that the mechanisms contributing to NO y fluxes, at least at this site, are much more complex than previously recognized. We show that the observations of upward fluxes of HNO 3(g+p) and σPNs during summer are consistent with oxidation of NO 2 and acetaldehyde by an OH x residence time of 1.1×10 10 molec OH cm −3 s, corresponding to 3 to 16×10 7 molecules cm −3 OH within the forest canopy for a 420 to 70 s canopy residence time. We show that ΣAN (g+p) fluxes are consistent with this range in OH if the reaction of OH with ΣANs produces either HNO 3 or NO 2 with a 6–30% yield. Calculations of NO fluxes constrained by the NO 2 observations and the inferred OH indicate that NO x fluxes are downward into the canopy because of the substantial conversion of NO x to HNO 3 and σPNs in the canopy. Even so, we derive that NO x emission fluxes of ~15 ng(N) m −2 s −1 at midday during summer are required to balance the NO x and NO y flux budgets. These fluxes are partly explained by estimates of soil emissions (estimated to be between 3 and 6 ng(N) m −2 s -1 ). One possibility for the remainder of the NO x source is large HONO emissions. Alternatively, the 15 ng(N) m −2 s −1 emission estimate may be too large, and the budget balanced if the deposition of HNO 3 and σPNs is slower than we estimate, if there are large errors in either our understanding of peroxy radical chemistry, or our assumptions that the budget is required to balance because the fluxes do not obey similarity theory.
Prevalence of Chlamydia trachomatis and Neisseria gonorrhoeae Infection in Pediatric Private Practice

Background. Universal screening of sexually active adolescents for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) has been recommended in settings in which prevalence is 2% or greater. Although believed to be above 2%, the prevalence of CT and GC infection in private practice settings has not been clearly established and may affect screening practices. Objectives. To determine CT and GC infection prevalence in 2 pediatric private practices. Design. Cross-sectional study. Setting. Two pediatric private practices in suburban North Carolina. Patients. Convenience sample of patients aged 15 to 24 years who were seen from August 1998 through June 1999. Main Outcome Measures. Prevalence of CT and GC infection. Results. Of 1114 eligible patients, 803 (72%) completed questionnaires and provided urine specimens tested for CT and GC infection using ligase chain reaction assays. Mean age was 17.1 years (standard deviation: 1.8). Most participants were female (63%), white (87%), and from highly educated families (64% of their mothers graduated from college). Sexual activity was reported by 41%. Prevalence of CT infection in all participants was 0.9% (confidence interval [CI]: 0.4%–1.8%); in sexually active participants, 2.1% (CI: 0.9%–4.3%); in sexually active females, 2.7% (CI: 1.0%–5.7%); and in sexually active males, 0.9% (CI: 0.0%–5.1%). One case of GC infection was found. Conclusions. The prevalence of CT and GC infection in this private practice population was much lower than reported in other settings. Screening recommendations may need to be reassessed if other low prevalence populations are found.
Targeting cancer cells in the tumor microenvironment: opportunities and challenges in combinatorial nanomedicine

Cancer therapies of the future will rely on synergy between drugs delivered in combination to achieve both maximum efficacy and decreased toxicity. Nanoscale drug delivery vehicles composed of highly tunable nanomaterials ('nanocarriers') represent the most promising approach to achieve simultaneous, cell-selective delivery of synergistic ratios of combinations of drugs within solid tumors. Nanocarriers are currently being used to co-encapsulate and deliver synergistic ratios of multiple anticancer drugs to target cells within solid tumors. Investigators exploit the unique environment associated with solid tumors, termed the tumor microenvironment (TME), to make 'smart' nanocarriers. These sophisticated nanocarriers exploit the pathological conditions in the TME, thereby creating highly targeted nanocarriers that release their drug payload in a spatially and temporally controlled manner. The translational and commercial potential of nanocarrier-based combinatorial nanomedicines in cancer therapy is now a reality as several companies have initiated human clinical trials.
A miR-297/hypoxia/DGK-α axis regulating glioblastoma survival.

Background. Despite advances in the treatment of the most aggressive form of brain tumor, glioblastoma, patient prognosis remains disappointing. This failure in treatment has been attributed to dysregulated oncogenic pathways, as observed in other tumors. We and others havesuggestedtheuseofmicroRNAs(miRs)astherapeutictoolsabletotargetmultiplepathwaysinglioblastoma. Methods. ThisworkfeaturesPCRquantificationofmiRs and transient transfection of many glioblastoma cell lines with miRs, followed by cell number analysis, trypan blue staining, alamarBlue assay of cell viability, caspase-3/-7 activity assay, immunoblot of cleaved poly(ADP-ribose) polymerase and fluorescence activated cell sorting and imaging of apoptotic nuclei, cell invasion assays, MRIs of glioblastoma xenografts in mice using transiently transfected cells as well as posttumor treatment with lentiviral vector encoding miR-297, and analysis of miR-297 target diacylglycerol kinase (DGK)‐a including immunoblot, 3 ′ UTRluciferaseactivity,andrescuewithDGK-aoverexpression. Cell counts and DGK-a immunoblot were also analyzedinthecontextofhypoxiaandwithoverexpression of heterogeneous ribonucleoprotein L (hnRNPL). Results. We identified miR-297 as a highly cytotoxic microRNA in glioblastoma, with minimal cytotoxicity tonormalastrocytes.miR-297overexpressionreducedin vitro invasiveness and in vivo tumor formation. DGK-a is shown to be a miR-297 target with a critical role in miR-297 toxicity. In addition, hypoxia and its mediator hnRNPL upregulated DGK-a and buffered the cytotoxic effects of miR-297. Conclusion. This work shows miR-297 as a novel and physiologic regulator of cancer cell survival, largely
Anomalous seaward dip of the lithosphere–asthenosphere boundary beneath northeastern USA detected using differential‐array measurements of Rayleigh waves

SUMMARY Rayleigh wave phase velocities and azimuth anomalies in the period range of 30‐100 s are measured for a set of four triangular arrays of broad-band seismometers in coastal northeastern USA. This is a region in which a strong upper mantle slow shear velocity anomaly (a ‘New England Anomaly’), crosses the continental margin. Earthquakes from a wide range of directions are used to detect the variation of parameters with azimuth, θ, of propagation. No lateral heterogeneity in phase velocity is detected at these periods between stations at the centre and the edge of the Anomaly. However, large (10‐20 per cent) azimuthal variations occur, and have a cos(1θ) dependence, which is indicative of a dipping structure in the upper mantle. Corresponding azimuth variations, with a magnitude of ±5 ◦ , are also detected. This behaviour is consistent with a southeasterly (N150 ◦ E) dip of the lithosphere‐asthenosphere boundary beneath New England. This dip is associated with the shoaling of the New England Anomaly beneath the Adirondack mountains, west of the array. It is opposite to the dip associated with lithospheric thickening toward the interior of the craton.
Properties of a recombinant human hemoglobin with aspartic acid 99 (β), an important intersubunit contact site, substituted by lysine

Site-directed mutagenesis of an important subunit contact site, Asp-99(beta), by a Lys residue (D99K(beta)) was proven by sequencing the entire beta-globin gene and the mutant tryptic peptide. Oxygen equilibrium curves of the mutant hemoglobin (Hb) (2-15 mM in heme) indicated that it had an increased oxygen affinity and a lowered but significant amount of cooperativity compared to native HbA. However, in contrast to normal HbA, oxygen binding of the recombinant mutant Hb was only marginally affected by the allosteric regulators 2,3-diphosphoglycerate or inositol hexaphosphate and was not at all responsive to chloride. The efficiency of oxygen binding by HbA in the presence of allosteric regulators was limited by the mutant Hb. At concentrations of 0.2 mM or lower in heme, the mutant D99K(beta) Hb was predominantly a dimer as demonstrated by gel filtration, haptoglobin binding, fluorescence quenching, and light scattering. The purified dimeric recombinant Hb mutant exists in 2 forms that are separable on isoelectric focusing by about 0.1 pH unit, in contrast to tetrameric hemoglobin, which shows 1 band. These mutant forms, which were present in a ratio of 60:40, had the same masses for their heme and globin moieties as determined by mass spectrometry. The elution positions of the alpha- and beta-globin subunits on HPLC were identical. Circular dichroism studies showed that one form of the mutant Hb had a negative ellipticity at 410 nm and the other had positive ellipticity at this wavelength. The findings suggest that the 2 D99K(beta) recombinant mutant forms have differences in their heme-protein environments.
Scientific Rigor and Distance Education

Three quotes are central to the development and growth of the field of distance education. These statements represented the themes of classic articles written by leaders in education and remain today as guides for the field. The first was by James Finn, one of the founders of the modern educational technology field. In 1953, in the introductory issue of Audio-Visual Communication Review, he wrote:
Interleukin-8 (IL-8): The Major Neutrophil Chemotactic Factor in the Lung

A number of novel chemotactic cytokines are becoming increasingly recognized as important participants in the elicitation of specific inflammatory cells from the peripheral blood to sites of inflam...
Warning: The Short Days of Winter May Be Hazardous to Your Health

Almost all living organisms have evolved biological rhythms linked to the day-night or light-dark cycles of the sun. The impact of such rhythms that follow the time of day and season of the year on a variety of physiological functions in humans has been recognized for a long time. The internal oscillator, or control station regulating the body’s circadian clock, is the suprachiasmatic nucleus (SCN), a tiny (70 000 neurons) structure situated in the hypothalamus.1 Located above the optic chiasm, the SCN processes external signals, such as ambient light and inputs from the brain, to regulate a variety of cyclical functions, including body temperature, sleep/wake cycles, and secretion of hormones such as serum cortisol, melatonin, thyroxin, and vasopressin.2 Ambient light can entrain the SCN, which then modulates physiological and pathophysiological processes. In fact, like modulated parasystole,3 a burst of light striking the photoreceptors in the morning can advance the SCN cycle, whereas a burst in the evening can delay the phase-response curve. In humans, the SCN sets the intrinsic 24-hour cycle accurately to average ≈24 hours and 11 minutes.4 In addition to daily modulation by the SCN, seasonal fluctuations in body rhythms occur. For example, plasma l-tryptophan and competing amino acids are significantly lower in the spring, changes that parallel seasonal variations in the prevalence of violent suicide and depression.5 The seasonal affective disorder syndrome (SADS) is a well-established entity characterized by depression during the winter months. Psychiatrists have treated SADS patients by exposing them to artificial light for 2 hours each morning to simulate an earlier sunrise.6 We have known for a number of years that circadian fluctuations affect, and perhaps orchestrate, a variety of pathophysiological states. The onset of myocardial infarction, sudden cardiac death, and stroke are all increased from 6 …
Uncultivated Bacteria as Etiologic Agents of Intra-Amniotic Inflammation Leading to Preterm Birth

Intra-amniotic infection and inflammation are major causes of preterm birth (PTB). However, intra-amniotic inflammation is often detected in the absence of infection. This may partly be due to the culturing methods employed in hospital laboratories, which are unable to detect the uncultivated species. In this study, intra-amniotic microbial infections associated with PTB were examined by both culture and 16S rRNA-based culture-independent methods and were corroborated by the presence of intra-amniotic inflammation. Amniotic fluid (AF) specimens from 46 pregnancies complicated by PTB and 16 asymptomatic women were analyzed. No bacterial DNA was amplified in AF collected from the asymptomatic women. Among the 46 samples associated with PTB, bacterial DNA was amplified from all (16/16) of the culture-positive samples and 17% (5/30) of the culture-negative samples. In the culture-positive group, additional species were detected in more than half (9/16) of the cases by PCR and clone analysis. Altogether, approximately two- thirds of the species detected by the culture-independent methods were not isolated by culture. They included both uncultivated and difficult-to-cultivate species, such as Fusobacterium nucleatum, Leptotrichia (Sneathia) spp., a Bergeyella sp., a Peptostreptococcus sp., Bacteroides spp., and a species of the order Clostridiales. To examine intra-amniotic inflammation, an AF proteomic fingerprint (mass-restricted score) was determined by surface-enhanced laser desorption ionization-time-of-flight mass spectrometry. Inflammation was detected in all five samples which were culture negative but PCR positive. Women who were PCR positive more often had elevated interleukin-6 levels in their AF, histological chorioamnionitis, and funisitis and delivered neonates with early-onset neonatal sepsis. Previously unrecognized, uncultivated, or difficult-to-cultivate species may play a key role in the initiation of PTB.