cssi/SciSciGPT-SciSciNet huggingface dataset:
The Nanomechanical Effect of Dendrimer Interlayers Underneath Cu Ultrathin Films

Two kinds of dendrimers, DAB and PAMAM (with the same terminal groups but different branched repeat units), were chosen as interlayers for Cu ultrathin films deposited on native oxide Si(100) wafers. 10 nm Cu thin films were deposited directly on the dendrimer monolayers by DC sputtering at room temperature. The nanomechanical results show that PAMAM and DAB have significant effects on the properties of the resulting films, with the DAB layer acting as a stiffer ‘spring’, compared to PAMAM, underneath the Cu films. Both dendrimer interlayers lower the hardness of the film, compared to Cu alone; the effect is greater for PAMAM than DAB interlayers. However, the introduction of either dendrimer monolayer significantly increased the elasticity of the Cu film.
The control of a stirred tank reactor with hysteresis in the control element - II describing function analysis

Abstract The method of the describing function is outlined and applied both to the linear problem and to the stirred tank. The hysteresis element is separable and the assumption is made that the signals to it are of sinusoidal form when the reactor is operating with a limit cycle. In spite of the shakiness of this assumption the agreement between calculated and estimated frequencies is very good and the agreement is amplitude good for small hysteresis. It is concluded that the method may be usefully applied to reactor problems when limit cycles are likely to be present.
Teaching Learning Strategies to Increase Success of First-Term College Students

In this study, the authors examined the effect of taking a learning strategies course on grade point average, retention, and graduation rate of 351 first-year students over their first 4 terms in comparison with 351 matched non–course takers. The course taught 4 learning strategies and 8 substrategies to help students overcome procrastination, build self-confidence, take responsibility, learn from lecture and text, prepare for exams, write papers, and manage their lives. First-year students who took the course in their first term had statistically significantly higher grade point averages in each of their first 4 terms. They also demonstrated statistically significantly higher retention rates and were six times more likely to be retained. In addition, they had statistically significantly higher graduation rates than did their matched controls. In particular, graduation rates were 50% higher for students initially in academic difficulty. These findings reveal the value of teaching learning strategies to fi...
Energy absorption and damage propagation in 2D triaxially braided carbon fiber composites: effects of in situ matrix properties

Results from an experimental program to investigate the propagation of damage and energy dissipation in 2D triaxially braided carbon fiber textile composites (2DTBC) under static conditions are reported. A methodology is presented in which classical concepts from fracture mechanics are generalized to address damage growth in an orthotropic and heterogeneous structural material. Along with results from the experimental program, a novel numerical technique that employs ideas from cohesive zone modeling, and implemented through the use of finite-element analysis, is also presented. The inputs that are required for the discrete cohesive zone model (DCZM) are identified. Compact tension specimen fracture tests and double notched tension tests were carried out to measure the fracture energy (GIc), and the maximum cohesive strength (σc), of the 2DTBC. The DCZM modeling strategy was independently verified by conducting single edge notched three-point bend tests using a modified three-point bend test fixture. The experimental and numerical analyses were carried out for two different types of 2DTBC made from the same textile architecture but infused with two different resin systems to validate the proposed methodology.
Low-affinity nerve growth factor receptor (P75 NGFR) as a marker of perineural invasion in malignant melanomas.

Background: Perineural invasion (PNI) is a well-recognized route of tumor extension in cutaneous neoplasms. Despite an established association with increased local recurrences and metastases, the mechanisms responsible for PNI have yet to be elucidated. We hypothesize that P75 NGFR, a nerve growth factor receptor, may be implicated in the pathogenesis of PNI in these tumors. Methods: P75 NGFR immunohistochemical staining was performed on 47 skin tumors with PNI including invasive squamous cell carcinomas (SCCs = 29), basal cell carcinomas (BCCs = 8) and malignant melanomas (MMs = 10). These were compared with similar lesions without PNI (SCCs = 7, BCCs = 7 and MMs = 9). Results: P75 NGFR staining was absent in all invasive SCCs irrespective of the presence of PNI (n = 0/36). Two BCCs with PNI (n = 2/8) and three without PNI (n = 3/7) showed focal P75 NGFR staining. Interestingly, 8 of 10 invasive MMs with PNI had positive P75 NGFR expression (80%), in contrast to only 1 of 9 without PNI (11%). Conclusions: P75 NGFR may play a mechanistic role in invasive MMs demonstrating PNI. Furthermore, its expression may serve as a marker of PNI in those tumors that lack histological evidence of nerve involvement at the time of excision. Chan MM, Tahan SR. Low-affinity nerve growth factor receptor (P75 NGFR) as a marker of perineural invasion in malignant melanomas.
A clinical staging system for multiple myeloma. Correlation of measured myeloma cell mass with presenting clinical features, response to treatment, and survival

The presenting clinical features of 71 patients with multiple myeloma were correlated with myeloma cell mass (myeloma cells X 10(12)/m2 of body surface area) determined from measurements of monoclonal immunoglobulin (M-component) synthesis and metabolism. Bivariate correlation and multivariate regression analyses showed that myeloma cell mass could be accurately predicted from A) extent of bone lesions, B) hemoglobin level, C) serum calcium level, and D) M-component levels in serum and urine. Analyses of response to chemotherapy and survival indicated significant correlation with measured myeloma cell burden. The results were synthesized to produce a very reliable and useful clinical staging system with three tumor cell mass levels (Table 7). For clinical research purposes, multivariate regression equations were developed to predict optimally the exact myeloma cell mass. Thus, initial staging can be quantitatively related to followup using tumor cell mass changes calculated from changes in M-component production. Use of the clinical staging system sould provide better initial assessment and followup of individual patients, and should lead to improved study design and analysis in large clinical trials of therapy for multiple myeloma.
Promotion of lung tumor growth by interleukin-17

Recent findings demonstrate that inhaled cigarette smoke, the predominant lung carcinogen, elicits a T helper 17 (Th17) inflammatory phenotype. Interleukin-17A (IL-17), the hallmark cytokine of Th1...
Improving Care and Outcomes of Uninsured Persons with Chronic Disease … Now

The article by Wilper and colleagues in this issue tells us that chronic disease is rampant among uninsured persons. This editorial identifies opportunities for policy reforms and outlines what eve...
Deterioration modelling for lateritic-base flexible pavements

Abstract Pavement roughness prediction models are generally simplifications of the actual relationships because of the complexity associated with the interaction between the various factors that affect deterioration. Models for roughness progression for flexible pavements using simplified incremental algorithms with actual field data of primary variables are presented. The field data used is obtained for flexible pavements with lateritic gravel bases and subbases with surface treatment as wearing course in Ghana, West Africa. The data covered major primary and secondary highways carrying a wide spectrum of traffic loading. The results indicate that environmental factors and structural capacity have significant influence on roughness progression. The strength of the pavement has a greater influence than the traffic loading on roughness progression, other factors remaining the same. Restoring the structural capacity of flexible pavements through timely maintenance intervention may help arrest the rate of deterioration. Direct transferability of models between different environmental, physical and operating conditions has its limitations and is not advisable.
PREDICTORS AND IMPACT OF NON-CIRCULAR LEFT VENTRICULAR OUTFLOW TRACT SHAPES ON ESTIMATION OF SEVERITY OF AORTIC STENOSIS BY CONTINUITY EQUATION

Continuity equation used to calculate aortic valve (AV) area in patients with aortic stenosis (AS) assumes a circular left ventricular outflow tract (LVOT) shape. However, > 50% of AS patients have non-circular LVOT shapes, potentially invalidating the standard continuity method. Predictors of which
Notes on Schneider’s stability estimates for convex sets

In 2009 Schneider obtained stability estimates in terms of the Banach–Mazur distance for several geometric inequalities for convex bodies in an n-dimensional normed space \({\mathbb{E}^n}\). A unique feature of his approach is to express fundamental geometric quantities in terms of a single function \({\rho:\mathfrak{B} \times \mathfrak{B} \to \mathbb{R}}\) defined on the family of all convex bodies \({\mathfrak{B}}\) in \({\mathbb{E}^n}\). In this paper we show that (the logarithm of) the symmetrized ρ gives rise to a pseudo-metric dD on \({\mathfrak{B}}\) inducing, from our point of view, a finer topology than Banach–Mazur’s dBM. Further, dD induces a metric on the quotient \({\mathfrak{B}/{\rm Dil}^+}\) of \({\mathfrak{B}}\) by the relation of positive dilatation (homothety). Unlike its compact Banach–Mazur counterpart, dD is only “boundedly compact,” in particular, complete and locally compact. The general linear group \({{\rm GL}(\mathbb{E}^n)}\) acts on \({\mathfrak{B}/{\rm Dil}^+}\) by isometries with respect to dD, and the orbit space is naturally identified with the Banach–Mazur compactum \({\mathfrak{B}/{\rm Aff}}\) via the natural projection \({\pi:\mathfrak{B}/{\rm Dil}^+\to\mathfrak{B}/{\rm Aff}}\), where Aff is the affine group of \({\mathbb{E}^n}\). The metric dD has the advantage that many geometric quantities are explicitly computable. We show that dD provides a simpler and more fitting environment for the study of stability; in particular, all the estimates of Schneider turn out to be valid with dBM replaced by dD.
Design and construction of a direct hydro powered coffee depulper

Abstract Coffee is an important agricultural product throughout much of the developing world. Harvesting and processing of coffee beans are a labor intensive endeavor, and much of this effort is provided by people. One physically demanding step is depulping, or removing the coffee “cherry” from its husk. Reducing the need for manual labor is one way to improve the quality of life for agricultural communities. A team from the Appalachian State University, USA designed, built, and installed a direct hydro-powered coffee depulper at Finca Esperanza Verde, Nicaragua in 2007. The hydro turbine is a commercially available WaterMotor which provides around 200 W of power. The system has performed flawlessly through five harvests. This paper describes the system and challenges that the team faced from design through construction. It is hoped that this project can serve as a model for other small direct hydro projects in the region.
Increased incidence of dyskinesias and other behavioral effects of re-exposure to neuroleptic treatment in social colonies of Cebus apella monkeys

Rationale: Typical neuroleptic medications are still administered to as many as 40% of patients receiving antipsychotic treatment in the US. Intermittent administration or interruption of long-term neuroleptic medication for schizophrenia may increase the incidence of human tardive dyskinesias, and similarly may produce increasingly marked motor side-effects, parkinsonism, and other behavioral pathologies in non-human primates. Objectives and methods: Given these similarities, we addressed the issue of prolonged and intermittent typical neuroleptic treatment and dopaminergic function during a 5-year, multi-phase study with social colonies of Cebus apella monkeys. In the previously reported phase 1, we examined the effects of 48 weeks of exposure to, followed by withdrawal from, fluphenazine decanoate (FPZ). Phase 3 reported here examined the effects of 18 weeks of re-exposure to FPZ in these same monkeys, 91 weeks after discontinuation of their phase 1 FPZ treatment. Results: Analysis of blood plasma FPZ indicated levels of 0.22±0.08 ng/ml for the six injections during the re-exposure period (n=54), comparable to the 0.24±0.07 ng/ml levels measured during our original treatment with this dose. Acute dyskinesias and dystonias increased by 300% upon re-exposure to FPZ; 15 of 18 FPZ-treated animals exhibited oral-buccal dyskinesias and all exhibited torticollis or retrocollis. Retreatment with FPZ was also associated with highly significant reductions in Self- and Environment-Directed Behavior and Directed Affiliation, effects similar to those seen during the original phase 1 FPZ treatment. Although FPZ re-treatment was associated with a significant reduction in Directed Aggression (an effect that was more robust than that observed during phase 1), in phase 3, we again observed an increase in Directed Aggression during early drug discontinuation when animals were in a stress-inducing situation. Conclusions: These results both support our phase 1 conclusion that typical neuroleptic medications may contribute to negative symptoms of schizophrenia and provide additional evidence for the possibility of increased aggression in stressful situations when medication is discontinued. Additionally, the results indicate that intermittent treatment with typical neuroleptics may dramatically increase the incidence of dystonias and dyskinesias.
A photographic technique for assessing the viewing‐angle performance of liquid‐crystal displays

— Liquid-crystal displays (LCDs) have notable variation in luminance and perceived contrast as a function of the angle from which they are viewed. Though this is an important performance issue for LCDs, most evaluation techniques for assessing this variation have been limited to laboratory settings. This study demonstrates the use of a photographic technique for such an evaluation. The technique is based on an actively cooled charge-coupled-device (CCD) detector in combination with a macro lens covering a circular angular range (θ) of ±42.5°. The camera was used to evaluate the luminance and perceived contrast properties of an LCD. Uniform field images corresponding to 17 equally spaced gray-scale values in the digital driving level (DDL) range of the display system were acquired. The 12-bit gray-scale digital images produced by the camera were converted to luminance units (cd/m2) via the measured luminance vs. DDL response function of the camera. The changes in perceived contrast as a function of viewing angle were derived from the Barten model of the gray-scale response of the human-visual system using the methods proposed by the AAPM TG18 Report. The results of this photographic technique were compared to measurements acquired from a similar display using a Fourier-optics-based luminance meter. The results of the two methods generally agreed to within 5%. The photographic methods used were found to be accurate and robust for in-field assessment of the angular response of LCDs over the FOV of the camera.
Relationship between loading process and Masing behavior in cyclic deformation

Abstract Masing behavior was investigated based upon the observed shapes of hysteresis loops in polycrystalline copper cycled with different loading methods. It was found that ramp-loaded specimens showed strong Masing behavior, whereas specimens tested in load control behaved much less in this aspect. To understand the above results, an elastic-perfect plastic multiphase model was given and friction stress and back stress analyses were carried out in support. The mechanism and results given in this letter are consistent with other results on cyclic deformation which contribute to understanding Masing behavior.
Spectral Properties of Random and Deterministic CMV Matrices

The CMV matrices are unitary analogues of the discrete one-dimensional Schrodinger operators. We review spectral properties of a few classes of CMV matrices and describe families of random and deterministic CMV matrices which exhibit a transition in the distribution of their eigenvalues.
Accuracy of StepWatch™ and ActiGraph Accelerometers for Measuring Steps Taken among Persons with Multiple Sclerosis

Introduction There has been increased interest in the objective monitoring of free-living walking behavior using accelerometers in clinical research involving persons with multiple sclerosis (MS). The current investigation examined and compared the accuracy of the StepWatch activity monitor and ActiGraph model GT3X+ accelerometer for capturing steps taken during various speeds of prolonged, over-ground ambulation in persons with MS who had mild, moderate, and severe disability. Methods Sixty-three persons with MS underwent a neurological examination for generation of an EDSS score and undertook two trials of walking on the GAITRite electronic walkway. Participants were fitted with accelerometers, and undertook three modified six-minute walk (6MW) tests that were interspersed with 10–15 minutes of rest. The first 6MW was undertaken at a comfortable walking speed (CWS), and the two remaining 6MW tests were undertaken above (faster walking speed; FWS) or below (slower walking speed; SWS) the participant's CWS. The actual number of steps taken was counted through direct observation using hand-tally counters. Results The StepWatch activity monitor (99.8%–99.9%) and ActiGraph model GT3X+ accelerometer (95.6%–97.4%) both demonstrated highly accurate measurement of steps taken under CWS and FWS conditions. The StepWatch had better accuracy (99.0%) than the ActiGraph (95.5%) in the overall sample under the SWS condition, and this was particularly apparent in those with severe disability (StepWatch: 95.7%; ActiGraph: 87.3%). The inaccuracy in measurement for the ActiGraph was associated with alterations of gait (e.g., slower gait velocity, shorter step length, wider base of support). Conclusions This research will help inform the choice of accelerometer to be adopted in clinical trials of MS wherein the monitoring of free-living walking behavior is of particular value.
Photo-oxidation of Cr(III)-citrate complexes forms harmful Cr(VI).

Photo-oxidation is a potential pathway for the transformation of Cr(III) to Cr(VI) in natural environments. In this study, the Cr(III)−citrate complex (Cr(III)−cit) was prepared and its speciation was determined by high performance liquid chromatography (HPLC). Results showed that Cr(III)−cit existed in [Cr(III)−H−cit]+ and [Cr(III)−cit] species in a pH range of 3−5, in [Cr(III)−cit] only from pH 6−8, in [Cr(III)−cit] and [Cr(III)−OH−cit]− from pH 9−11, and only in [Cr(III)−OH−cit]− at pH 12. Additional experiments were conducted in batch systems with pHs of 5 to 12 at 25 °C, where aqueous Cr(III) and Cr(III)−cit were fully exposed to light from medium pressure mercury lamps and a xenon lamp mimicking solar light irradiation. Results demonstrated that oxidation of Cr(III) in Cr(III)−cit was much faster than that in aqueous Cr(III). Rates of Cr(III) photo-oxidation were not sensitive to pH in the range from 7 to 9 but increased significantly with further increases in pH, which was consistent with the distr...
The crack epidemic: Empirical findings support an hypothesized diffusion of innovation process

Abstract The popularity of crack cocaine grew dramatically in the 1980s and became the primary drug of abuse in much of the United States. This paper examines variation in the reported year of first use by 724 crack abusers from New York City. The finding of a dramatic increase in first use from 1984 to 1986 is consistent with a word-of-mouth process of diffusion primarily within a pre-existing population of persistent hard-drug abusers. In particular, many of these early crack abusers were already either snorting cocaine powder or smoking it as freebase prior to first use of crack. These findings suggest that policies focusing on reducing use of a single drug such as crack are unlikely to solve the broader problem of hard-drug abuse. As an alternative, drug-abuse policies might be more effective to the extent that they focus on discouraging youths from initiating the use of any hard drugs and encouraging drug abusers to stop by offering some form(s) of treatment.
Blind synchronisation for OFDM

A blind synchronisation method for an OFDM system operating over a wireless frequency selective channel is presented. There are two restrictions: (i) the constellation on each subcarrier must have points equally spaced in phase and (ii) the length of the guard interval must be chosen from a subset of allowed values. The frequency offset acquisition range is ~±1/8 of the total OFDM symbol bandwidth.
Stimulation of hydrocortisone-induced rat liver tryptophan pyrrolase by triamterene.

Abstract Pretreatment with triamterene (2,4,7-triamino-6-phenylpteridine) results in significant increase in the level of endogenous holotryptophan pyrrolase over the induction caused by hydrocortisone alone. The pteridine perhaps results in a favorable stoichiometric ratio in vivo of apotryptophan pyrrolase and the heme coenzyme.
Gamma interferon as an antifibrosis agent in skeletal muscle

Abstract Muscle injuries are a common problem in sports medicine. Skeletal muscle can regenerate itself, but the process is both slow and incomplete. Previously we and others have used growth factors to improve the regeneration of muscle, but the muscle healing was impeded by scar tissue formation. However, when we blocked the fibrosis process with decorin, an antifibrosis agent, we improved the muscle healing. Here we show that γinterferon (γINF)––a cytokine that inhibits the signaling of transforming growth factor β1 (TGFβ1), a fibrotic stimulator––reduces fibrosis formation and improves the healing of lacerated skeletal muscle. With γINF treatment, the growth rate of muscle-derived fibroblasts was reduced and the level of fibrotic protein expression induced by TGFβ1 (including TGFβ1, vimentin, and α-smooth muscle actin) was down-regulated in vitro. In a mouse laceration model, the area of fibrosis decreased when γINF was injected at either 1 or 2 weeks after injury. More importantly, the injection of γINF at either 1 or 2 weeks post-injury was found to improve muscle function in terms of both fast-twitch and tetanic strength. This study demonstrates that γINF is a potent antifibrosis agent that can improve muscle healing after laceration injury.
Habitat selection of rodents along a pinon-juniper woodland- savannah gradient

The biodiversity of pinon-juniper (P-J) woodlands of western North America has received increasing attention from conservationists because of concerns about woodland invasion into adjacent shrub-steppe communities. Small mammals contribute substantially to the faunal diversity of P-J woodlands, but the responses of small mammals to the inherent structural complexity of these woodlands have not been well described. We used occupancy modeling and ordination to describe habitat selection along a woodland-savannah gradient of 4 species of rodents, including 2 putative P-J woodland specialists, Peromyscus truei and Tamias dorsalis .W e accounted for the influences of season and prior conspecific capture on detectability. P. truei and T. dorsalis preferred old-growth woodland sites near rock outcrops with high canopy and bare-ground cover and low herb and shrub cover. Tamias minimus preferred savannah sites with high shrub and grass cover farther from rock outcrops. We found no evidence of resource selection along the gradient by Perognathus parvus. Our results provide insight into the role of habitat selection in facilitating coexistence among closely related species within P-J woodlands and suggest that management efforts that better discriminate between old, presettlement stands and young, invasive stands may enhance regional biodiversity. We demonstrate an effective application of occupancy modeling for describing habitat selection of cryptic rodents, which are particularly prone to imperfect detection. DOI: 10.1644/09-MAMM-A-060.1.
Prevention of Extracellular K+ Inhomogeneity Across the Ischemic Border by Coronary Venous Obstruction in the Dog: Salutary Antiarrhythmic Effects of Enhanced Myocardial Hydration

Partial coronary sinus obstruction (CSO) in the dog prevents or delays the predictable ventricular fibrillation (VF) of the early phase of acute ischemia, by normalizing regional electrophysiological disparities which presumably reflect inhomogeneous extracellular potassium ([K+]o) accumulation. To clarify whether CSO indeed affects [K+]o inhomogeneity, we determined in 12 chloralose anesthetized dogs the dynamic [K+]o changes occurring early during reversible coronary artery occlusion (CAO) involving the mid-left anterior descending branch. These changes were compared to those observed during CAO preceded by CSO sufficient to increase the coronary sinus pressure to 40 mmHg. [K+]o was determined using valinomycin coated electrodes implanted within the ischemic (IZ) and the normal (NZ) zones, as well as immediately inside (BZi) and outside (BZo) the visible border. [K+]o increased rapidly within the IZ and the BZi reaching plateau 5 min after CAO, at about three-fold control (11.89 +/- 1.12 mEq/l). Unexpectedly, [K+]o also increased initially outside the border (BZo) but declined after 3 min to a lower level (7.00 +/- 0.40 mEq/l), thus creating a steep gradient of up to 5.54 +/- 0.20 mEq/l, P < 0.001) across the visible border. In four trials, the gradient coincided with VF. With CSO preceding CAO, the development of this border zone gradient was entirely prevented. Moreover, [K+]o reached a significantly lower and similar level in the IZ, BZi and BZo (9.5 +/- 0.89 mEq/l, P < 0.001) and no VF was observed. Thus the beneficial electrophysiologic and antiarrhythmic effects of CSO in acute ischemia may be explained by [K+]o equalization.(ABSTRACT TRUNCATED AT 250 WORDS)
Transition strengths and new band structures in odd-odd 78Rb.

High-spin states in $^{78}\mathrm{Rb}$ were studied using the $^{54}\mathrm{Fe}$${(}^{28}$Si,3pn) reaction at 120 MeV and the $^{58}\mathrm{Ni}$${(}^{23}$Na,2pn) reaction at 65 and 70 MeV. Prompt and delayed \ensuremath{\gamma}-\ensuremath{\gamma} coincidences were measured using the Pitt-FSU detector array. Results from these experiments have led to new levels partly grouped into new bands, new spin-parity assignments, and a rearrangement of the low-lying portion of the level scheme. States were observed up to (${19}^{+}$) and (${15}^{\mathrm{\ensuremath{-}}}$) in the lowest energy positive- and negative-parity bands. Spin assignments were based on both directional correlation of oriented nuclei ratios and angular distributions. For some low-lying levels parity assignments were supported by a measurement of the linear polarizations of \ensuremath{\gamma} rays. Lifetimes were determined using the Doppler-shift attenuation method and direct timing. A reversal of signature splitting was observed in the yrast band at the ${10}^{+}$ state. Large alternations were seen in the B(M1) strengths in the yrast band, while the B(E2) values in the two most strongly populated bands show a considerable collective enhancement. \textcopyright{} 1996 The American Physical Society.
Student Paper Dispersal patterns and clumping behaviors in the beetle Trichoton sordidum

Although a significant number of behavioral studies of desert tenebrionids have been done, almost nothing is recorded of Trichoton sordidum (LeConte) (Coleoptera: Tenebrionidae), an inhabitant of the sunny, sparsely vegetated US/Mexican borderlands. For this small, flightless beetle successful predator evasion and adaptation to a desert environment has required development of complicated, quickly utilizable behavioral mechanisms for regulating exposure to extremes of heat, light, humidity, and habitat structure. In this study, T. sordidum was exposed to sudden changes in temperature, illumination, and habitat complexity, and some patterns representing its normal aggregation were recorded. Minimum Risk Distribution models ([Floater 2001][1]) predict changes in spatial distribution patterns of groups of individuals as they are exposed to environmental change. A successful species must have a large percentage of individuals adhering to changes with a set pattern of behaviors. All groups of T. sordidum tested demonstrated both rapid and cohesive dispersal patterns. They normally showed little tendency toward clustering, except clear adhesive aggregation patterns in cases of limited resources in a fragmented environment. Under conditions of extreme heat or light, aggregations in the form of clumping did occur. The formation of clumps from simple two-stacks to groups of up to ten is documented here. The sophistication, consistency of use, and rapid initiation of clumps suggest clumping might well be a highly evolved and successful mechanism for group threat evasion. The morphology of T. sordidum shows how clumping is achieved. An examination of the conditions leading to clumping gives clues to why clumps are formed. * Abbreviations : MRD : Minimum Risk Distribution: A model of spatial distribution of individuals that results in the minimum number of premature deaths in a population, and leads to maximized population growth ([Floater 2001][1]). C-value : A statistical measurement used in this study to quantify relative clump sizes for Trichoton sordidum rather than total number of individuals in a clump. Homogeneous environment : Environment composed only of uniform, similar features with no irregular detail. In this experiment, open areas of sand, cloth, or fine debris were used. Habitat complexity : Structural interference in a habitat which leads to spatial variability. The result is predicted to be a change in the spatial distribution of individuals within the habitat. In this study pebbles were added to the homogeneous environment to break up a uniform surface area. [1]: #ref-6
CARIOGENICITY OF COMMON SUGARS AS EVALUATED IN THE ARTIFICIAL MOUTH

THE artificial mouth is a device for simulating in vitro the principal oral conditions presumably involved in dental caries1. Qualitatively, the in vitro lesions produced in human teeth are similar to those produced naturally2–4. The method has been used for the quantitative evaluation of anti-caries agents and dentifrices5–7.
Norfenfluramine, the fenfluramine metabolite, provides stimulus control: evidence for serotonergic mediation.

Abstract Nine male rats were trained to discriminate 1.4 mg/kg norfenfluramine (NF) from its vehicle using a two-lever, food-motivated, operant discrimination task. Once trained, the rats showed a dose-dependent decrease in responding on the NF-correct lever following decreased doses of NF (ED50=0.71mg/kg). Administration of 2.0 mg/kg fenfluramine (FEN) produced 100% responding on the NF-correct lever and decreasing doses of FEN, likewise, produced a dose-dependent decrease in responding on the NF-correct lever (ED50=1.30 mg/kg). Time-course data indicated that NF has a fast onset and a peak effect at 20–60 min after administration. Analysis of the time-course data provided a half-life of approximately 8 hr. In contrast, FEN did not show the rapid onset that was observed with NF. However, NF had a similar peak effect ahd half-life. These results indicate a pharmacological similarity between NF and FEN. However, the difference in onset of action suggests a possible difference between the parent drug and its metabolite. The serotonergic agonists mCPP, DOI, 5-MeODMT and LSD generalized to 1.4 mg/kg NF, whereas neither TFMPP nor 8-OHDPAT generalized to NF. The dopaminergic agonist AMPH also did not generalize to NF. The implications of these findings are discussed.
Branched-chain amino acid oxidation by isolated rat tissue preparations

Abstract Branched-chain amino acid transaminase activity, branched-chain α-keto acid dehydrogenase activity, and leucine oxidation were measured in homogenates and slices of several rat tissues. Transaminase activity was highest in heart, while dehydrogenase activity was highest in liver. Leucine oxidation in isolated tissues may be limited by either transaminase or dehydrogenase activity depending upon the relative activities of these two enzymes in the tissue. The results suggest that, as the load of branched-chain amino acids increases, the liver may become an increasingly important site for the degradation of branched-chain α-keto acids.
Preliminary study of thyrotrophin releasing hormone stimulation test in chronic low back pain patients

Chronic pain has been considered as a variant of depression or as a masked depression. In an attempt to unravel the complex relationship between chronic pain and depression, we administered the TRH stimulation test to a uniform group of chronic pain patients classified into those with and without major depression using DSM-III criteria. Eighteen percent showed blunting of TSH response to TRH. There was no significant difference between the two groups.
Molecular cloning and expression of an α-mannosidase gene in Mycobacterium tuberculosis

Mannose is a major component of glycolipids and glycoproteins of the cell envelope of M. tuberculosis (Mtb). However, the enzymes involved in the biosynthesis and catabolism of mannosylated glycans are largely unknown. We demonstrate alpha-mannosidase activity towards the fluorescent substrate 4-methylumberlliferyl-alpha-D-mannopyranoside (4MU-Man) in cell lysates of attenuated and virulent Mtb bacilli, with two-fold higher activity in the virulent strain Erdman. Mannosidase activity was optimal at pH 6.5, was not inhibited by deoxymannojirimycin (dMNJ), was mildly inhibited by swainsonine (SW) and stimulated two-fold by EDTA. GenBank BLAST analysis for sequences homologous to eukaryotic alpha-mannosidases revealed a 3.6 kb putative gene (Rv0648) in Mtb cosmid SCY20H10 (Acc# z92772), with strong homology (48%) to the rat ER/cytosolic alpha-mannosidase and containing signature sequences of class 2 mannosidases. By RT-PCR, gene Rv0648 was found differentially expressed, with lower expression during growth in A549 pneumocyte cultures. Gene Rv0648 was cloned, expressed in E. coli, and alpha-mannosidase activity in cell lysates determined. Expression of alphaMan-pET in E. coli cells resulted in an eight-fold increase in mannosidase activity toward 4-MU-Man, upon IPTG induction. Partial purification of the histidine-tagged Mtb mannosidase by metal chelation affinity chromatography, and analysis by SDS-PAGE, showed a protein with the predicted m.w. of 137.5 kDa. Enzyme assays of the column fractions showed alpha-mannosidase activity toward synthetic aryl-mannose substrates, in fractions enriched in the recombinant Mtb mannosidase. These results demonstrate that gene Rv0648 encodes an active alpha-mannosidase in Mtb.
Counsel for chemists

Guide to the Chemical Industry: Technology, R & D, Marketing, and Employment. By William S. Emerson. Wiley: 1984. Pp.330. £35, $40.25. Problem Solving in the Chemical Industry. By R. J. Casey and M. J. Frazer. Pitman: 1984. Pp.122. Pbk £8.95.
Reply to Frère: Covalent Trapping and Bacterial Resistance to Ceftazidime

This is a response to a letter by Frere (1). Dr. Frere's letter and insightful comments are appreciated. We investigated the role of Arg-164 in the KPC-2 carbapenemase using biochemical and microbiological assays (2). Our variants were expressed in a laboratory strain, Escherichia coli DH10B, and the gene was encoded in a high copy vector (pBC SK). The R164S variant demonstrated increased ceftazidime minimum inhibitory concentrations (MICs); our argument for covalent trapping was based upon the detection of the acyl-enzyme complex of the R164S variant and ceftazidime. Our results suggested the hypothesis that rapid turnover of ceftazidime did not appear to be the only cause of the high ceftazidime MIC of the R164S variant. From our observations (mass spectrometry), the R164S variant instead appeared to “trap ceftazidime,” thus preventing it from reaching its PBP targets. We also ran Western blots using a polyclonal antibody that measured KPC β-lactamase. Our Western blots showed that steady-state expression levels paralleled the resistance to ampicillin and cephalothin. As Fig. 3 shows, the R164S variant expressed in this laboratory strain of E. coli produced a significant amount of R164S KPC β-lactamase. We agree that accurately measuring the amount of β-lactamase produced in these experimental strains may give us better insights. Efforts will be undertaken to develop a specific ELISA for KPC-β-lactamase as we have done in other studies to help approximate the true amount of enzyme (3). However, we wonder if, in strains of E. coli or Klebsiella pneumoniae recovered from the clinic, calculations may not be entirely precise as many factors impact the MIC (porin loss, other β-lactamase production, permeability, etc.).
Patent ductus arteriosus treated with ligation orindomethacin: A follow-up study

The course and complications of fifty-two infants with patent ductus arteriosus requiring closure were assessed prospectively. Twenty-six infants with a PDA received indomethacin for pharmacologic closure of the PDA, and 26 underwent ligation. The current study analyzes and compares the longitudinal follow-up with respect to somatic growth, neurologic function, psychomotor and mental development, and renal, ophthalmologic, and audiologic function in 21 infants in each group who entered the follow-up. No selective morbidity was attributable to PDA closure with indomethacin when compared to surgically treated infants.
Alleviating the curse of dimensionality – A psychologically-inspired approach

Abstract Various combinations of perceptual features are relevant for learning and action-selection. However, the storage of all possible feature combinations presents computationally impractical, and psychologically implausible, memory requirements in non-trivial environments due to a state-space explosion. Some psychological models suggest that feature combinations, or chunks, should be generated at a conservative rate (Feigenbaum and Simon, 1984). Other models suggest that chunk retrieval is based on statistical regularities in the environment, i.e. recency and frequency (Anderson and Schooler, 1991). We present a computational model for chunk learning based on these two principles, and demonstrate how combining these principles alleviates state-space explosion, producing exponential memory savings while maintaining a high level of performance.
Social influence and the estimation of time

The usefulness of time estimation as a standard task in social-influence studies was determined by replicating Sherif’s autokinetic research. Divided into two conditions, Ss received 15-, 45-, or 75-sec time intervals during two sessions. Half of the Ss wrote estimates in Session 1 and gave oral estimates in Session 2. The other half of the Ss gave oral estimates during Session 1 and wrote estimates in Session 2. The results were in agreement with Sherif’s autokinetic research, indicating that time estimation is an acceptable substitute for the autokinetic effect, which is expensive and cumbersome.
TagNetLens: multiscale visualization of knowledge structures in social tags

Social tags reflect personal and shared vocabulary, and provide opportunities for people to organize and search information. However, tags are usually not structured. To find relevant tags and associated documents, people often need to invest significant amount of cognitive resources to make sense of the relationships among tags. To help the sensemaking of social tags and exploration of knowledge structure of them, we propose an approach of tag networks, TagNet, in which tags are linked by their corresponding documents and a multiscale tag hierarchy are derived with network clustering and aggregation techniques. We also present TagNetLens, an interactive tool that allows users to explore a tag network and its tag hierarchy. We report a case study of TagNet and TagNetLens based on social tags and documents from CiteULike. The results indicate that our TagNet approach can provide users with knowledge structures that are similar to cognitive structures of concepts in people's minds, and TagNetLens can help people to better explore the space of social tags and may have potentials to facilitate the understanding of the knowledge structure in social tags.
The Qualitative Method of Impact Analysis.

Consider the qualitative approach to evaluation design (as opposed to measurement) to be typified by a case study with a sample of just one. Although there have certainly been elaborate and emphatic defenses of the qualitative approach to program evaluation, such defenses rarely attempt to qualify the approach explicitly and rigorously as a method of impact analysis. The present paper makes that attempt. The problem with seeking to advance a qualitative method of impact analysis is that impact is a matter of causation and a non-quantitative approach to design is apparently not well suited to the task of establishing causal relations. The root of the difficulty is located in the counterfactual definition of causality, which is our only broadly accepted formal definition of causality for social science. It is not, however, the only definition we use informally. Another definition, labeled “physical causality,” is widely used in practice and has recently been formalized. Physical causality can be applied to ...
Influences of salinity and shade on seedling photosynthesis and growth of two mangrove species, Rhizophora mangle and Bruguiera sexangula, introduced to Hawaii

Abstract Rhizophora mangle was first introduced to Hawaii in 1902 to promote shoreline stabilization. Intertidal competition with native and introduced salt marsh species was low, and beyond the early 1920s, mangrove forests expanded rapidly. An additional mangrove species, Bruguiera sexangula, was introduced in 1922 and currently co-occurs with R. mangle in only a few stands on the north shore and windward sides of Oahu. Where the two species overlap, R. mangle, having colonized intertidal zones first, forms nearly monospecific forest stands. To determine why R. mangle remains the dominant mangrove, we initiated a greenhouse study to compare seedling growth and photosynthetic light response of both species growing at two light levels and contrasting salinity regimes (2, 10, 32 PSU). The asymptotic nature of B. sexangula’s assimilation response is indicative of stomatal regulation, whereas only light level appears to regulate photosynthesis in R. mangle. Shifts in patterns of biomass allocation and physiological response indicate two contrasting strategies relative to sunlight and salinity. B. sexangula’s strategy is characterized by slow growth with little variation under favorable conditions and morphological plasticity under stressful conditions, which allows for adjustments in carbon gain efficiency (morphological strategy). On the other hand, R. mangle’s strategy involves faster growth under a wide range of environmental conditions with physiological enhancement of carbon assimilation (physiological strategy). Low salinity combined with reduced light, or simply low sunlight alone, appears to favor R. mangle and B. sexangula equally. High salinity places greater, but not overwhelming, stress on B. sexangula seedlings, but tends to favor R. mangle at higher light levels.
Radiochemical quality control of short-lived radiopharmaceuticals

Radiochemical purity, the fraction of radioactivity present in the specified chemical form, is a major factor determining the reproducibility of a nuclear medicine diagnostic procedure. Impurities may arise during preparation and storage of radiopharmaceuticals and will frequently modify organ distribution and specificity, possibly leading to an incorrect diagnosis of the patient's health. This review is a guide to radiochemical analytical principles for those who develop new short-lived radiopharmaceuticals. The applicability of some recently developed methods is contrasted with conventional techniques, and guidelines are suggested for predicting the best separatory mechanism to apply to a new radiochemical quality control problem. The selected method(s) should be sensitive, reproducible, separate all possible components without causing changes in sample composition, and preferably be convenient to perform.
Organophosphate Resistance Mediated by Alterations of Acetylcholinesterase in a Resistant Clone of the Greenbug, Schizaphis graminum (Homoptera: Aphididae)

An organophosphate (OP)-resistant clone (OR-0) of the greenbug, Schizaphis graminum, showed 27.2-, 19.9-, 65.8-, 44.5-, 18.2-, 4.8-, and 3.1-fold greater resistance to dimethoate, omethoate, disulfoton, demeton-S-methyl, parathion, methyl parathion, and chlorpyrifos, respectively, than an OP-susceptible clone (OSS). General esterase and glutathione S-transferase activities were similar in the OSS and OR-0 clones, whereas cytochrome P450 O-demethylase activities were below the detection limit in both greenbug clones. In contrast, acetylcholinesterase (AChE) activity in the OR-0) clone was 2.3-fold higher than that in the OSS clone. Kinetic studies also revealed that AChE from the OR-0 clone was 2.1-, 2.1-, 1.6-, 4.4-, and 1.3-fold less sensitive to inhibition by methyl paraoxon, paraoxon, demeton-S-methyl, omethoate, and demeton S, respectively, than AChE from the OSS clone (P < 0.05). However, Northern blot analysis of mRNA, using a 296-bp AChE cDNA fragment generated by seminested PCR as a homologous probe, indicated that the increased activity of AChE in the OR-0 clone was not due to the overexpression of the AChE gene. Our overall results suggest that the increased AChE activity in the OR-0 clone most likely is due to structural modifications of AChE, leading to both an increased catalytic activity with the model substrate acetylthiocholine and a reduced sensitivity to inhibition by OP compounds.
A randomized controlled trial of early oral analgesia in gynecologic oncology patients undergoing intra-abdominal surgery

Abstract OBJECTIVE: To evaluate the safety and efficacy of early oral analgesia after intra-abdominal surgery in gynecologic oncology patients. METHODS: Over a 2.5-year period, 227 gynecologic oncology patients undergoing intra-abdominal surgery were enrolled in a randomized controlled trial of early oral versus traditional parenteral analgesia. All patients initially received parenteral morphine via a patient-controlled analgesia (PCA) pump with a basal dose of 0.5 mg/h and a PCA dose of 1 mg with a 10-minute lockout. On the first postoperative day, all patients began a clear liquid diet, which was advanced as tolerated. Patients allocated to early oral analgesia were switched from parenteral to oral morphine. They received a scheduled dose of 20 mg every 4 hours with an additional dose of 10 mg every 2 hours as needed for breakthrough pain. Patients allocated to traditional parenteral analgesia continued to receive parenteral morphine via a PCA pump with basal and PCA doses. On the second postoperative day, the scheduled oral and basal parenteral doses were discontinued. The oral and parenteral PCA doses were continued until 24 hours before discharge, at which time the patient was switched to oxycodone 5 mg/acetaminophen 325 mg. RESULTS: There were no significant differences among the groups in any demographic or clinical indices, including age, case distribution, surgery length, blood loss, time to return of bowel function, length of hospital stay, pain, sedation, and satisfaction scores, and incidence of nausea, vomiting, or major postoperative complications. CONCLUSIONS: Early oral analgesia in gynecologic oncology patients undergoing intra-abdominal surgery is safe and efficacious.