cssi/SciSciGPT-SciSciNet huggingface dataset:
Context-dependent inversion of the response in a single sensory neuron type reverses olfactory preference behavior

The valence and salience of individual odorants are modulated by an animals innate preferences, learned associations, and internal state, as well as by the context of odorant presentation. The mechanisms underlying context-dependent flexibility in odor valence are not fully understood. Here we show that the behavioral response of C. elegans to bacterially-produced medium-chain alcohols switches from attraction to avoidance when presented in the background of a subset of additional attractive chemicals. This context-dependent reversal of odorant preference is driven by cell-autonomous inversion of the response to alcohols in the single AWC olfactory neuron pair. We find that while medium-chain alcohols inhibit the AWC olfactory neurons to drive attraction, these alcohols instead activate AWC to promote avoidance when presented in the background of a second AWC-sensed odorant. We show that these opposing responses are driven via engagement of different odorant-directed signal transduction pathways within AWC. Our results indicate that context-dependent recruitment of alternative intracellular signaling pathways within a single sensory neuron type conveys opposite hedonic valences, thereby providing a robust mechanism for odorant encoding and discrimination at the periphery.
Recognition Performance of Cross-Spectral Periocular Biometrics and Partial Face at Short and Long Standoff Distance

Matching partial heterogeneous face images to a gallery of visible images is a challenging research problem. This scenario is motivated by a number of surveillance applications such as recognition of subjects at night or in the presence of challenging environmental conditions. Standoff distances may range from a meter to hundred meters. Our latest experiments have shown that a face recognition software recently developed in our research group can be adapted to perform cross spectral matching of partial face images. The images are encoded with Gabor Generalized Local Binary Patterns and Gabor Weber operators and matched by means of a Kullbuck-Leibler metric. Our analysis has shown that three separate face regions such as (1) eyes and nasal bridge, (2) cheeks and nasal tip, and (3) mouth and a part of the chin display similar matching performance. Furthermore, we have evaluated performance of periocular regions. For a short standoff distance of 1.5 meters and a database of 48 classes, matching a Short Wave Infrared (SWIR) periocular region against visible regions resulted in 0.7 Genuine Accept Rate (GAR) at False Accept Rate (FAR) set to 0.01. For a long standoff distance of 106 meters and a database of 48 classes, matching SWIR against visible periocular regions yielded 0.4 GAR at FAR equal to 0.1. For a short standoff distance of 1.5 meters and a database of 200 classes, matching a Medium Wave Infrared (MWIR) periocular region against visible regions resulted in 0.35 GAR at FAR set to 0.1.
Effects of Operating Parameters on Surface Quality for Laser Cutting of Mild Steel

Over the last 20 years, laser cutting and drilling, welding, surface heat treatment, cladding, scribing, balancing, and other laser systems have gradually made their way into the industrial workplace. However, there remain significant uncertainties in the understanding of the important physics of laser-material interaction and in material removal processes. Most research focuses on a one- or two-controlling-parameter investigation of cut quality. Furthermore, the implied definition of quality most often involves kerf width and HAZ, not surface roughness. The present work constitutes a quantitative experimental study to determine the effects of cutting speed, assist gas pressure, and thickness on the surface roughness of laser-cut mild steel. The effects of focal plane location and laser power level were also studied through a series of factorial design experiments. This systematic approach, combined with a constraint that a minimally acceptable cut must yield a surface roughness smaller than that produced by a band saw, allowed a large number of operating parameters to be investigated with a moderate number of individual experiments. A unique aspect of the study was the use of wedge-shaped test pieces which were 2.5 cm wide with a thickness varying from 0.05 cm to 0.65 cm over a 15 cm length.more » In this way, surface quality at a given cutting speed could be determined for a range of thicknesses using a single cut.« less
A unity power factor forward converter

A novel means of obtaining sinusoidal, unity power factor input currents in switched mode power supplies using minimum additional components is presented. The converter is topologically equivalent to a boost converter cascaded by a forward power converter, but is realized using only a single power stage. A detailed analysis of the operation is presented. A constant frequency current mode control provides excellent transient performance at the output and sinusoidal input currents at the input. Various tradeoffs involved in the design of the converter elements and control parameters are discussed in depth. All the results are backed up by experimental waveforms from a laboratory converter. >
The Cosmos: Astronomy in the New Millennium

The fifth edition of The Cosmos: Astronomy in the New Millennium provides you with the fundamentals of astronomical knowledge that have been built up over decades, with an expanded discussion of the incredible advances that are now taking place in this fast-paced field, such as New Horizons' flyby of Pluto, exoplanets, 'dark matter', and the direct detection of gravitational waves by the Laser Interferometer Gravitational-Wave Observatory (LIGO). Written in a clear and easily understandable style, this textbook has been thoroughly revised to include updated data and figures, new images from recent space missions and telescopes, the latest discoveries on supernovae, and new observations of the region around the four-million-solar-mass black hole at the center of our Milky Way Galaxy. A rich array of teaching and learning resources is available at http://thecosmos5.com. The website is regularly updated to include the latest discoveries and photographs in the field.
The Stellar IMF, Core Mass Function, & The Last-Crossing Distribution

Hennebelle & Chabrier 2008 (HC08) attempted to derive the stellar IMF as a consequence of turbulent density fluctuations, using an argument similar to Press & Schechter 1974 for Gaussian random fields. Like that example, however, this solution does not resolve the 'cloud in cloud' problem; it also does not extend to large scales that dominate the velocity/density fluctuations. In principle, these can change the results at the order-of-magnitude level. Here, we use the results from Hopkins 2011 (H11) to generalize the excursion set formalism and derive the exact solution in this regime. We argue that the stellar IMF and core mass function (CMF) should be associated with the last-crossing distribution, i.e. the mass spectrum of bound objects defined on the smallest scale on which they are self-gravitating. This differs from the first-crossing distribution (mass function on the largest self-gravitating scale) which is defined cosmologically and which H11 show corresponds to the GMC mass function in disks. We derive an analytic equation for the last-crossing distribution that can be used for an arbitrary collapse threshold in ISM and cosmological studies. With this, we show that the same model that predicts the GMC mass function and large-scale structure of galaxy disks also predicts the CMF (and by extrapolation IMF) in good agreement with observations. The only adjustable parameter in the model is the turbulent velocity power spectrum, which in the range p~5/3-2 gives similar results. We also use this to justify why the approximate solution in HC08 is reasonable (up to a normalization) over the CMF/IMF mass range; however there are significant corrections at intermediate and high masses. We discuss how the exact solutions here can be embedded into time-dependent models that follow density fluctuations, fragmentation, successive generations of star formation.
Using large vs. small group projects in capstone and software engineering courses

Teamwork is viewed as an increasingly important facet of an education in Computer Science and related fields. One common way to include teamwork in the undergraduate curriculum is to include team projects in various course offerings. I have taught both large-group and small-group projects in upper-division undergraduate courses within the recent past. This paper compares these experiences from my viewpoint as an instructor, and identifies the factors that I have found most indicative of quality projects in both types of courses.
The Meaning and Utility of Institutional Teaching Evaluations

This study analyzes end of course institutional teaching evaluations (ITEs) done anonymously by students in a pre-service teacher education course over a 15-year span. The purpose was to determine if and how the ITE findings might inform practice and relate to teaching metaphors as a tool of study. Analysis revealed: (a) teacher effectiveness ratings were more meaningful when examined by metaphor periods and when outliers, which skewed the trends, were removed, (b) patterns in students’ optional narrative comments on ITEs indicated that students consistently saw instructor strength in caring and weakness in clarity, (c) there was no clear correlation between narrative comments and teacher effectiveness ratings, and (d) alignment with identified teaching metaphors was strongest with student narrative comment categories. In addition, doing this analysis reframed the way I thought of myself as a teacher and allowed me to make positive changes in how I related to students. Comments from the course in the seme...
Implicit Social Cognition: Attitudes, Self-Esteem, and Stereotypes.

Social behavior is ordinarily treated as being under conscious (if not always thoughtful) control. However, considerable evidence now supports the view that social behavior often operates in an implicit or unconscious fashion. The identifying feature of implicit cognition is that past experience influences judgment in a fashion not introspectively known by the actor. The present conclusion--that attitudes, self-esteem, and stereotypes have important implicit modes of operation--extends both the construct validity and predictive usefulness of these major theoretical constructs of social psychology. Methodologically, this review calls for increased use of indirect measures--which are imperative in studies of implicit cognition. The theorized ordinariness of implicit stereotyping is consistent with recent findings of discrimination by people who explicitly disavow prejudice. The finding that implicit cognitive effects are often reduced by focusing judges' attention on their judgment task provides a basis for evaluating applications (such as affirmative action) aimed at reducing such unintended discrimination.
Intensity-dependent circular polarization and circumstellar magnetic fields from the observation of SiO masers

A new aspect of the propagation of astrophysical maser radiation in the presence of a magnetic field is described in which circular polarization is created. The resulting antisymmetric spectral line profile for this circular polarization resembles that produced by the ordinary Zeeman effect when the Zeeman splittings are much less than the spectral line breadth. It is caused by the change, with increasing maser intensity, in the axis of symmetry for the molecular quantum states from a direction that is parallel to the magnetic field to a direction that is parallel to the direction of propagation. When the maser is radiatively saturated, and the rate for stimulated emission is within an order of magnitude of the Zeeman splitting in frequency units, this 'intensity-dependent circular polarization' is greater than that due to the ordinary Zeeman effect by factors as large as 1000. The circular polarization that is observed in the spectra of circumstellar SiO (J = 1-0) masers associated with late-type giants and supergiants may then be caused by magnetic fields as weak as about 10 mG. With the standard Zeeman interpretation of the observations, magnetic fields of 10-100 G are indicated. The lower fields are similar to the limits obtained from the observation of the 22 GHz water masers which are typically somewhat further from the central star. The observed tendency for the fractional linear polarization of SiO masers to increase with increasing angular momentum of the molecular state is shown to be a likely result of anisotropic pumping. Errors are identified that invalidate a recent conflicting claim in the literature about the basic theory of maser polarization in the regime that is relevant here.
Control of stem cell proliferation: A density-dependent commitment model

A developmental model for the control of stem cell proliferation is presented. The model seeks to account for the production of both static and self-renewing tissues. It is assumed that in both cases the probability of stem cell commitment is a function of cell number or cell density. In the static tissues the commitment process is such that the supply of stem cells comes to be exhausted. In the self-renewing tissues the probability of commitment is homeostatically regulated at one half. Implicit in the model is a potential mechanism to account for the (species-specific) upper limit to animal size.
Twenty-first century managed mental health: Point-of-service treatment networks

The managed care product of the twenty-first century in behavioral health is the point-of-service plan now favored by many employers. This paper describes the nature of such a managed care product and its impact on mental health. Those designing the new delivery system must (1) construct the “right” system which husbands resources for the good of the patient, (2) choose the “right” providers, (3) employ the “right” financial incentives, and (4) undertake the “right” oversight training of network providers and analysis of care outcomes.
Inversion of Love-wave data for velocity and anelasticity using exact kernels

Summary. The general problem of inverting Love-wave dispersion and amplitude data to obtain a velocity and Qs structure is considered. A formulation is used which incorporates attenuation into the Haskell-Thompson matrix method in an exact manner and thus retains the inherent non-linearity in the anelasticity. The resulting exact inversion kernels allow simultaneous inversion for velocity and intrinsic attenuation parameters. The method is applied to synthetic data which allows a comparison to be made with inexact kernels. The results indicate that the use of inexact kernels may introduce spurious oscillations into the Qs structure and that a simultaneous inversion can be more stable than inverting for velocity alone.
Syndicating Web Services: A QoS and user-driven approach

Web Services that provide a real-time e-business solution via online binding of software components must have a mechanism to win users' confidence in the quality of service (QoS) to establish a solid foot holding in the market. Inspired by the trust third-party approach in the public key system, we explored the idea of expanding the role of registrars to include (1) assessing quality of Web Services and (2) syndicating Web Services. The Analytic Hierarchy Process (AHP) and the Brown-Gibson (BG) methods were adapted to facilitate quality assessment. An optimization model was proposed for Web Service syndication. A heuristic algorithm was developed to solve the NP-hard problem, and an experiment was conducted, with two sensitivity analyses involving adjusting parameters, to compare its performance and the optimal solutions.
Gut insulin from Foxo1 loss

Neuroendocrine cells, including those in the gut, have a vast array of functions. A new study shows that conditional inactivation of the gene encoding Foxo1 in mouse intestinal endocrine cells converts them into cells synthesizing and secreting insulin. Ectopic gut insulin production was sufficient to ameliorate glucose control in mice with conditional pancreatic β-cell loss and diabetes mellitus.
Transnasal esophagoscopy findings: Interspecialty comparison

Abstract Introduction Otolaryngologists implement transnasal esophagoscopy (TNE) to assess esophageal pathology. Previous studies using TNE are largely retrospective and deal with select patient populations. The prevalence of esophageal pathology in patients presenting with throat symptoms to an otolaryngology voice center is presently unknown. Objective To assess the prevalence of esophageal pathology in this population and determine the interobserver variability of the findings reviewed by an otolaryngologist and a gastroenterologist. Study Design A prospective study. Setting This study was conducted in a laryngology/voice subspecialty clinic. Subjects and Methods Fifty patients with throat symptoms presenting to the voice center were asked prospectively to undergo TNE. The findings were videotaped and reviewed by an otolaryngologist and a gastroenterologist blinded to the patients' presenting complaint. Results Hoarseness was the most common presenting symptom (68%). According to the gastroenterologist, the prevalence of esophageal findings was: z-line irregularity suspicious for Barrett esophagus (12%), esophagitis (10%), hiatal hernia (32%), and esophageal stricture (10%). The percent agreement for a normal study was 72 percent. The percent agreement for various pathological findings were as follows: Barrett esophagus 86 percent, esophagitis 88 percent, hiatal hernia 76 percent, and esophageal stricture 96 percent. For an abnormal study, the percent agreement was 80 percent. Conclusion Esophageal abnormalities are common in patients presenting to a voice subspecialty clinic.
The treatment of pediatric Philadelphia positive (Ph+) leukemias in the imatinib era.

Background As the treatment of Philadelphia positive (Ph+) leukemias in the era of imatinib continues to evolve, the role of allogeneic hematopoietic cell transplantation (allogeneic-HCT) in first remission is becoming more unclear. Procedure Thirty-two pediatric centers across the United States and Canada were surveyed regarding current treatment practices for Ph+ acute lymphoblastic leukemia (ALL) and chronic myelogenous leukemia (CML). The survey addressed treatment approaches for Ph+ ALL and CML in terms of imatinib therapy and use of allogeneic-HCT. Results Twenty-three of the 32 centers returned the survey to provide a 72% response rate. Of the 27 physicians responding to the survey, 22 (81%) recommended a matched sibling donor (MSD) allogeneic-HCT, when available, in first remission for Ph+ ALL compared to 17/27 (63%) for patients with first chronic phase CML. There was universal agreement among survey responders regarding the use of imatinib upfront in Ph+ ALL and CML patients while 13 of 27 (48%) physicians reported using imatinib as maintenance therapy post-HCT for Ph+ ALL compared to 9 of 27 (33%) for CML. Conclusions Although a treatment consensus did not exist based on the results of this small survey, current treatment practices for pediatric Ph+ ALL and CML appear to favor allogeneic-HCT when a MSD is available. The use of post-HCT imatinib as maintenance therapy to avoid relapse for either Ph+ ALL or CML remains uncertain and awaits future prospective studies. Pediatr Blood Cancer 2009;53:992–995. © 2009 Wiley-Liss, Inc.
International Financial Capital Transfers: A Transaction Cost Framework

This paper argues that a number of non-conventional types of foreign direct investments – such as free-standing firms – that fit awkwardly in models where multinational firms arise to exploit abroad their firm-specific advantages, can be explained by looking at the role of these institutions in the international transfer of financial capital. The paper develops a theory to explain why a particular form of transfer will be used based on the choice between price and hierarchical transfer on one hand, and intermediated versus non-intermediated transfer on the other. Hierarchical transfer (equity) will be favoured when transaction costs in the market for investible funds are high. Intermediation will take place when there is considerable asymmetry between savers and investors. Non-intermediated equity transfers (free-standing firms) will arise to finance projects offering no collateral (hence equity) but of low scale and known technology (hence non-intermediated).
The 'wired' universe of organic chemistry

The millions of reactions performed and compounds synthesized by organic chemists over the past two centuries connect to form a network larger than the metabolic networks of higher organisms and rivalling the complexity of the World Wide Web. Despite its apparent randomness, the network of chemistry has a well-defined, modular architecture. The network evolves in time according to trends that have not changed since the inception of the discipline, and thus project into chemistry's future. Analysis of organic chemistry using the tools of network theory enables the identification of most 'central' organic molecules, and for the prediction of which and how many molecules will be made in the future. Statistical analyses based on network connectivity are useful in optimizing parallel syntheses, in estimating chemical reactivity, and more.
Weierstrass representation for discrete isotropic surfaces in ℝ2,1, ℝ3,1, and ℝ2,2

Using an integrable discrete Dirac operator, we construct a discrete version of the Weierstrass representation for hyperbolic surfaces parameterized along isotropic directions in ℝ2,1, ℝ3,1, and ℝ2,2. The corresponding discrete surfaces have isotropic edges. We show that any discrete surface satisfying a general monotonicity condition and having isotropic edges admits such a representation.
Studies of laminar opposed-flow diffusion flames of acetylene at low-pressures with photoionization mass spectrometry

We have designed an opposed-flow flame system to investigate the chemical composition of non-premixed flames using in situ flame-sampling molecular-beam mass spectrometry with synchrotron-generated tunable vacuum-ultraviolet light as an ionization source. This paper provides details of the experimental apparatus, sampling method, and data-reduction procedures. To test the system, we have investigated the chemical composition of three low-pressure (30–50 Torr), non-premixed, opposed-flow acetylene(Ar)/O2(Ar) flames. We measured quantitative mole-fraction profiles as a function of the distance from the fuel outlet for the major species and several intermediates, including the methyl and propargyl radicals. We determined the temperature profiles of these flames by normalizing a sampling-instrument function to thermocouple measurements near the fuel outlet. A comparison of the experimental temperature and major species profiles with modeling results indicates that flame perturbations caused by the sampling probe are minimal. The observed agreement between experimental and modeled results, apparent for most combustion species, is similar to corresponding studies of premixed flames.
Organic Spirocyclic Initiators for the Ring-Expansion Polymerization of β-Lactones

We report spirocyclic imidazolidines derived from N-heterocyclic carbenes and β-lactones. These spirocycles are initiators for the zwitterionic ring-expansion polymerization of β-lactones to generate cyclic polyesters of well-defined molecular weight. The zwitterionic strategy based on the equilibrium between the zwitterionic intermediates and spiro macrocyclics enables the controlled synthesis of cyclic poly(β-lactone)s
Local dynamic stability of amputees wearing a torsion adapter compared to a rigid adapter during straight-line and turning gait

Lower limb amputees have decreased balance during daily ambulation compared to nonamputees. An optimally compliant torsion adapter, which enables transverse plane rotation at the socket-pylon junction may reduce limb asymmetries and improve comfort leading to increased confidence and stability during gait. The purpose of this study was to determine if the presence of a torsion adapter affects amputee sensitivity to local perturbations (local dynamic stability) during straight-line walking and during a turning task. Ten unilateral transtibial amputees were fit with a torsion and rigid adapter in random order and blinded to the condition. After a 3-week acclimation period, kinematic data were collected while subjects walked in a straight-line on a treadmill and around a 1-m radius circular path at constant speed. Maximum finite-time Lyapunov exponents (λ), an estimator of local dynamic stability, were calculated for the amputee's sagittal plane hip, knee and ankle angles for each condition. The prosthetic limb λ was greater during a turn compared to straight-line walking, suggesting amputees are less stable while turning. There were no statistically significant differences found in λ between adapters during both walking conditions, suggesting the torsion adapter had no effect on amputee stability; however, high inter-subject variability due to the examined population and turning task may have masked a small decrease in prosthetic limb hip and knee stability for the torsion adapter during straight-line gait. Therefore, the torsion adapter's added degree of freedom may have a small adverse effect on prosthetic limb stability during straight-line walking and no effect on turning.
Effect of Sodium Vanadate on Deoxyribonucleic Acid and Protein Syntheses in Cultured Rat Calvariae

Sodium vanadate, an agent known to have multiple cellular actions, was studied for its effects on aspects of bone formation in cultures of 21-day-old fetal rat calvariae. Vanadate (0.1-10 microM) stimulated the incorporation of [3H] thymidine into acid-insoluble residues (DNA); the effect appeared after 3 h and was sustained for 96 h. Vanadate increased the bone DNA content and mitotic index. Treatment with vanadate at 10 microM for 24 h or at 0.3-1 microM for 96 h increased the incorporation of [3H]proline into collagenase-digestible protein (CDP), but the effect was not specific for collagen; vanadate also increased the labeling of noncollagen protein (NCP). Vanadate increased the incorporation of [3H]proline into type I collagen without affecting other collagen types. Vanadate (100 microM) caused a marked and irreversible inhibitory effect on the labeling of DNA, CDP, and NCP. Treatment with vanadate at multiple doses for 3-96 h did not stimulate alkaline phosphatase activity, but this enzyme was inhibited in bones exposed to 1 mM vanadate for 24 h or 10 microM vanadate for 96 h. The stimulatory effect on DNA labeling was primarily observed in the periosteum, while that on CDP labeling was seen only in the periosteum-free bone. These studies indicate that sodium vanadate stimulates bone DNA, collagen, and NCP syntheses in vitro, although high doses of vanadate have an irreversible inhibitory effect.
Activation energy for soot formation by C2-hydrocarbon/air flames

Engineering design and computer models in combustion often require data on the temperature dependence of the non-equilibrium, rate-controlled process of soot formation. Global apparent activation energies usually satisfy these needs in operational reaction kinetics, but they are not understood. A review of the combustion literature revealed that methods for determining the apparent global activation energy for combustion and soot formation are often rather involved and typically yield results with large uncertainties. The objective of the paper is to introduce and demonstrate a straightforward and more precise procedure for determining the pseudo-activation energy for soot formation. The method is based on the measurement of flame temperature and generates a result with a factor of 10 better precision. The new procedure has been demonstrated for soot formation by C2-hydrocarbon/air flames.
Mechanical properties of graphyne monolayers: a first-principles study

We investigated the mechanical properties of graphyne monolayers using first-principles calculations based on the Density Functional Theory. Graphyne has a relatively low in-plane Young's modulus (162 N m(-1)) and a large Poisson ratio (0.429) compared to graphene. It can sustain large nonlinear elastic deformations up to an ultimate strain of 0.2 followed by strain softening until failure. The single bond is more vulnerable to rupture than the triple bond and aromatic bond, although it has a shorter bond length (0.19 A shorter) than the aromatic bond. A rigorous continuum description of the elastic response is formulated by expanding the elastic strain energy density in a Taylor series in strain truncated after the fifth-order term. We obtained a total of fourteen nonzero independent elastic constants which are components of tensors up to the tenth order. Pressure effects on the second-order elastic constants, in-plane Young's modulus, and Poisson ratio are predicted. This study implies that graphyne-based surface acoustic wave sensors and waveguides may be synthesized by introducing precisely controlled local strains on graphyne monolayers.
Why Four Years

The traditional four‐year undergraduate program in civil engineering is constantly under pressure from the Accreditation Board for Engineering and Technology (ABET), industry, and educators themselves. The idea of a five‐year program is hardly a new one. There are many current factors that point to an increasing pressure to lengthen the current program. At the same time, student preparation and financial burdens have been factors in adding to the average time required to complete an undergraduate degree. This paper deals with the current climate and proposes an idea whose time has come again: a five‐year program leading directly to a master's degree. Those institutions that offered five‐year bach‐elor‐of‐science programs, as recently as the early 1960s, eventually found it difficult to compete for students. The professional program, leading directly to a master's degree, has also been attempted and usually was abandoned. The proposed program is a compromise that tries to address the concerns of everyone a...
A novel non-contact common-path Fourier domain optical coherence tomography method for intraocular lens power measurement in-vitro

We developed a novel non-contact common path FD-OCT method to measure the dioptric power of intraocular lenses in-vitro. This method can be applied to a wide range of IOLs.
Low energy behaviour of a three-body phase shift

We have calculated phase shifts, analytically and numerically, for an adiabatic long range potential, arising from the interaction of 3 particles in two dimensions. At large distances of the hyper radius r, the effective potential approaches (r 2 ln r)-1. We obtained the low energy dependence of the phase shifts which correspond to such a long range ‘tail’. We also studied the contribution to the phase shifts from the short range part of the potential.
Disappearance and excretion of labeled α-MSH in man☆

Abstract Despite the considerable evidence for the CNS actions of α-melanocyte-stimulating hormone (α-MSH) in man, little attention has been given to its half-time disappearance from plasma and urinary excretion in normal individuals. In the first experiment, a healthy man was given 15 μCi of tritiated ( 3 H)-α-MSH as a rapid IV injection. A plot of the disappearance time in plasma was characteristic of a multiexponential curve, the linear components of which were resolved by the subtraction method and half-time disappearance calculated directly from the slope of the regression line. The half-time disappearance was 1 min for the first component and 25 min for the second component. After the IV administration of 50 μCi of 125 I-α-MSH in the second experiment, the two components showed halftime disappearances of 1 min and 4.8 min respectively. These times were not changed by precipitation of the plasma with 10% trichloroacetic acid. Thirty-eight percent and 42% of the label appeared in the urine 4 hr after the injection of either 3 H-α-MSH or 125 I-α-MSH. The results suggest that the persistence of high levels of α-MSH in the blood after injection in man may be too short to fully explain the CNS effects of α-MSH.
Thermal diffusivity measurement of GaAs/AlGaAs thin-film structures

This work develops a new measurement technique that determines the thermal diffusivity of thin films in both parallel and perpendicular directions, and presents experimental results on the thermal diffusivity of GaAs/AlGaAs-based thin-film structures. In the experiment, a modulated laser source heats up the sample and a fast-response temperature sensor patterned directly on the sample picks up the thermal response. From the phase delay between the heating source and the temperature sensor, the thermal diffusivity in either the parallel or perpendicular direction is obtained depending on the experimental configuration. The experiment is performed on a molecular-beam-epitaxy grown vertical-cavity surface-emitting laser (VCSEL) structure. The substrates of the samples are etched away to eliminate the effects of the interface between the film and the substrate. The results show that the thermal diffusivity of the VCSEL structure is 5-7 times smaller than that of its corresponding bulk media. The experiments also provide evidence on the anisotropy of thermal diffusivity caused solely by the effects of interfaces and boundaries of thin films. 23 refs., 9 figs., 1 tab.
The Pure Rotation Spectra of N H 3 and N D 3

The pure rotation spectra of N${\mathrm{H}}_{3}$ and N${\mathrm{D}}_{3}$ have been measured in the spectral region from $40\ensuremath{\mu}$ to $170\ensuremath{\mu}$. Ten rotation lines of N${\mathrm{H}}_{3}$ corresponding to final $J$ values from 3 to 12 have been observed. These fall upon a curve given by $\ensuremath{\nu}=19.880J\ensuremath{-}0.00176{J}^{3}$. Thirteen lines of N${\mathrm{D}}_{3}$ corresponding to final $J$'s from 8 to 20 have been observed. These fall upon a curve given by $\ensuremath{\nu}=10.26J\ensuremath{-}0.00045{J}^{3}$.
Plasma population pharmacokinetics and penetration into cerebrospinal fluid of indinavir in combination with zidovudine and lamivudine in HIV-1-infected patients.

Objectives To evaluate plasma population pharmacokinetics and penetration into cerebrospinal fluid (CSF) by indinavir (IDV) in HIV-infected individuals receiving IDV, zidovudine and lamivudine. Methods Plasma population pharmacokinetic analysis was performed on 805 IDV plasma values from 171 patients, using a non-linear mixed-effects modeling approach. CSF data from 19 patients were analyzed using an individual approach. Results Mean individual Bayesian estimates for oral clearance (CL) and volume of distribution (V) by the final model that incorporated interoccasion variability were 0.75 l/h per kg [coefficient of variation (CV) 54.8%] and 1.74 l/kg (CV 82.7%), respectively. Mean model-predicted plasma IDV level at 8 h, maximal level, area under the plasma level-time curve up to 8 h and plasma half-life were 0.42 micromol/l (CV 57.5%), 9.51 micromol/l (CV 47.3%), 29.56 micromol/l x h (CV 46.9%) and 1.50 h (CV 20.9%), respectively. The mean IDV CSF level was 0.11 micromol/l (CV 49.7%) and the mean CSF:plasma concentration ratio was 0.017. Conclusions Population estimates of pharmacokinetic parameters of IDV and its CSF penetration were in excellent agreement with previously reported data from individual analyses. Intraindividual interoccasion variability of IDV pharmacokinetics was estimated to be of similar order of magnitude to its interindividual variability, which may affect response to long-term antiretroviral therapy involving IDV. CSF levels of IDV exceeded its in vitro 95% inhibitory concentration of HIV replication. Given that CSF is virtually free of protein, viral suppression in the central nervous system should be achievable with an IDV-containing regimen.
Optic nerve blood flow is diminished in eyes of primary open-angle glaucoma suspects.

Abstract PURPOSE: The purpose of this study was to evaluate optic nerve blood flow in primary open-angle glaucoma suspect eyes with normal automated visual fields, in an attempt to elucidate how early in the glaucomatous disease process changes in optic nerve blood flow become apparent. METHODS: Twenty-one eyes (21 patients) suspected of having primary open-angle glaucoma were studied prospectively and compared with a previously reported cohort of 22 eyes (22 patients) with primary open-angle glaucoma and 15 eyes (15 subjects) of age-matched controls. Primary open-angle glaucoma suspect eyes had untreated intraocular pressure greater than 21 mm Hg and normal visual fields using Humphrey program 24-2 or 30-2 with a full threshold strategy. Laser Doppler flowmetry was used to measure optic nerve head blood velocity, volume, and flow at four quadrants in the optic nerve, in the cup, and in the foveola of one eye of each patient. The mean flow from the superotemporal rim, inferotemporal rim, and cup was calculated (Flow 3 ) and identified as the main outcome measure. Measurements from primary open-angle glaucoma suspect eyes were compared with corresponding measurements from controls and eyes with primary open-angle glaucoma; a Student t test was employed with a Bonferroni corrected P value of .025 to account for comparisons of primary open-angle glaucoma suspects both to controls and to eyes with primary open-angle glaucoma. RESULTS: Compared with controls, Flow 3 was 24% lower in primary open-angle glaucoma suspect eyes ( P P P P CONCLUSIONS: Laser Doppler flowmetry detected circulatory abnormalities in primary open-angle glaucoma suspects who did not have any manifest visual field defect. Decreases in flow in glaucoma suspects were similar in magnitude to those of subjects with primary open-angle glaucoma. These data suggest that impaired optic nerve blood flow develops early in the glaucomatous process and does not develop solely as a result of glaucoma damage.
Measurement of semen quality, fertility, and reproductive hormones to assess dibromochloropropane (DBCP) effects in live rabbits.

Thirty-six sexually mature Dutch rabbits were divided into six equal groups to receive in the drinking water 5 days/week for 10 weeks 0, 0.94, 1.88, 3.75, 7.50, and 15.00 mg of DBCP/kg body wt. General health, body weight, semen quality (four ejaculates per male per week), and libido were measured throughout. Fertility, blood follicle stimulating hormone (FSH), luteinizing hormone (LH), and testosterone were measured the last week and caude epididymal sperm were examined at sacrifice. There was no effect of DBCP on general health or body weight. There was considerable variation in ejaculate volume, percentage motile sperm, and sperm concentration per milliliter within groups and among weeks. However, between the first 2 weeks and the last 2 weeks of the experiment sperm output had increased by 19% in the three lower DBCP groups and decreased by 16% in the three higher DBCP groups (p < 0.01). The proportion of sperm with abnormal tails also increased as DBCP dosage increased. Fertility was unaffected. FSH was elevated (p < 0.01) in the group receiving 15 mg/kg of DBCP, which is consistent with the impairment of spermatogenesis. Libido, LH, and testosterone levels were not affected. Sperm morphology was the most sensitive indicator of a DBCP effect in the live animal, being affected at a daily oral intake ≥ 1.88 mg DBCP/kg body wt.
LEE-WICK INDEFINITE METRIC QUANTIZATION: A FUNCTIONAL INTEGRAL APPROACH

Abstract In an attempt to study the stability of the Lee-Wick indefinite metric theory, the functional integral for indefinite metric quantum field theories is derived. Theories with an indefinite classical energy may be quantized with either a normal metric and an indefinite energy in Minkowski space or an indefinite metric and a positive energy in euclidean space. However, the functional integral in the latter formulation does not incorporate the Lee-Wick prescription for assuring the unitarity of the positive energy positive metric sector of the theory, hence the stability of the theory cannot be studied non-perturbatively.
Age-related differences in the distribution of peripheral atherosclerosis: When is atherosclerosis truly premature?

Background. The natural history of peripheral atherosclerosis in young adults appears to be unfavorable compared with that in older patients. No universally accepted definition of “premature” atherosclerosis exists, however, making comparison of clinical studies difficult. This study examined age-related differences in distribution of atherosclerotic lesions and determined an age threshold at which such differences became apparent. Such a threshold may provide a definition of premature atherosclerosis. Methods. Arteriograms of all patients 49 years of age and younger undergoing evaluation of lower extremity ischemia during the past 5 years were reviewed and the findings were tabulated. Medical records were reviewed to obtain demographic data, assess risk factors, and confirm disease etiology. Exclusion criteria included normal arteriograms (three patients), history of acute or remote trauma (six patients), unclear cause of ischemic symptoms (three patients), arteritis (four patients), aneurysmal disease (one patient), and acute ischemia without prior chronic symptoms (12 patients). For comparison we also reviewed arteriograms performed during the same period in 140 patients older than 50 years of age who had chronic lower extremity ischemia caused by atherosclerosis. Results. The mean age of the 59 study patients was 43.4±5.8 years (median age, 46 years; range, 25 to 49 years). Arteriograms were available in all cases; medical records were available in 54 (92%). Atherosclerosis involved only the aortoiliac segment in 25 patients (42%), the femoropopliteal-tibial arteries alone in 21 (36%), and both levels in 13 (22%). Patients with distal atherosclerosis had a higher prevalence of diabetes than those with proximal atherosclerosis (p=0.004). Ninety-two (66%) of the 140 patients older than 50 years of age had atherosclerosis confined to a single arterial segment, which was not significantly different from the prevalence of single-level disease in the study group. However, 25 (54%) of the 46 study patients with single-level atherosclerosis had aortoiliac disease compared with only 15 (16%) of 92 patients older than 50 years of age with single-level disease (p Conclusions. In contrast to the pattern of disease in older adults, atherosclerosis in young, nondiabetic patients most commonly involves the aortoiliac segment. Differences in lesion distribution become increasingly apparent with age but are most striking between those 49 years of age and younger and those 50 years of age and older. Accordingly, we propose that premature peripheral atherosclerosis be defined as beginning at or before the age of 49 years.
Meta-analysis: antibiotic therapy for small intestinal bacterial overgrowth

SummaryBackground Small intestinal bacterial overgrowth (SIBO) is an under-recognised diagnosis with important clinical implications when untreated. However, the optimal treatment regimen remains unclear. Aim To perform a systematic review and meta-analysis comparing the clinical effectiveness of antibiotic therapies in the treatment of symptomatic patients with documented SIBO. Methods Four databases were searched to identify clinical trials comparing effectiveness of: (i) different antibiotics, (ii) different doses of the same antibiotic and (iii) antibiotics compared with placebo. Data were independently extracted according to predetermined inclusion and exclusion criteria. Study quality was independently assessed. The primary outcome was normalisation of post-treatment breath testing. The secondary outcome was post-treatment clinical response. Results Of 1356 articles identified, 10 met inclusion criteria. Rifaximin was the most commonly studied antibiotic (eight studies) with overall breath test normalisation rate of 49.5% (95% confidence interval, CI 44.0–55.1) (44.0%–55.1%) then (46.7%–55.5%), then (4.6%–17.8%). Antibiotic efficacy varied by antibiotic regimen and dose. Antibiotics were more effective than placebo, with a combined breath test normalisation rate of 51.1% (95% CI 46.7–55.5) for antibiotics compared with 9.8% (95% CI 4.6–17.8) for placebo. Meta-analysis of four studies favoured antibiotics over placebo for breath test normalisation with an odds ratio of 2.55 (95% CI 1.29–5.04). Clinical response was heterogeneously evaluated among six studies, but tended to correlate with breath test normalisation. Conclusions Antibiotics appear to be more effective than placebo for breath test normalisation in patients with symptoms attributable to SIBO, and breath test normalisation may correlate with clinical response. Studies were limited by modest quality, small sample size and heterogeneous design. Additional higher quality clinical trials of SIBO therapy are warranted.
Low-noise readout IC with integrated analog-to-digital conversion for radiation detection system

A low-noise readout integrated circuit, comprising a charge sensitive amplifier, a pulse shaper with baseline holder, a peak detector and an A/D converter, is presented. The designed IC quantifies optical response of a large-area epitaxial photodiode integrated on a body of a semiconductor scintillator. The input transistor size and the time constant of the shaper are optimized to obtain a minimum equivalent noise charge(ENC) with the large input load capacitance. A time-based clockless A/D converter is implemented to minimize the interference of the digital part of the readout system on the low-noise charge-sensitive amplifier. The simulated ENC of the readout system interfacing a 50 pF capacitance and a dark current of 10 pA that model the epitaxial photodiode is 172 electrons at 12 μs time constant of the pulse shaper with power consumption of CSA and shaper of 2.2 mW.
Role of hepatic stellate cells in fibrogenesis and the reversal of fibrosis

Liver fibrosis is caused by many chronic diseases. Liver injury results in activation of collagen-producing cells and excessive deposition of extracellular matrix proteins. This process is orchestrated by many cell types. Hepatocytes apoptosis and inflammatory cells trigger secretion of profibrogenic and proinflammatory cytokines, such as transforming growth factor-beta1, angiotensin II, leptin, which in turn activates hepatic stellate cells, the major source of collagen type I. This review is focused on recent progress in the study of the pathogenesis of liver fibrosis.
Color flow mapping

Color flow mapping systems have become widely used in the short time since their development. These systems overlay a pseudo-color velocity map upon the gray-scale two-dimensional image. Between 4 and 16 pulses are directed to each line-of-sight, and this requirement reduces the frame rate in comparison with the gray-scale image. Other limitations of color flow mapping include its ability to estimate only the velocity toward or away from the transducer and an increase in the variance in comparison with spectral Doppler. Potential artifacts include aliased velocities and the detection of flow in hypoechoic or hyperechoic nonvascular structures. Clinical applications include cardiology, studies of the abdominal and peripheral vasculature, evaluation of organ perfusion and the differentiation of tumors. Most current systems use narrowband estimators that examine a fixed sample volume and detect a change in phase between two pulses. Wideband estimators that can track red blood cells in two or three dimensions are under evaluation. Narrowband estimators, including the autocorrelator, the short Fourier transform and second order autoregressive filters, are compared with wideband estimators including cross-correlation, sum-absolute-difference and the wideband maximum likelihood estimator. Because the intensity of blood echoes is far smaller than echoes from surrounding tissue, high pass filters have been developed that can reject the larger signal from tissue using the return from a small number of pulses. Other areas of research include strategies for flow estimation with contrast agents, three-dimensional color flow mapping and power Doppler flow mapping.