cssi/SciSciGPT-SciSciNet huggingface dataset:
Oscular contractions in sponges

1. 1. Oscula of a number of marine and fresh-water sponges contracted in response to mechanical but not to electrical stimulation. Contractility was related to abundance of myocytes as estimated histologically. Latency was 0·1–0·4 sec, contraction time 1–5 sec and relaxation time 15–60 sec. 2. 2. Responses were strictly local and no spatial summation or conduction was seen. Temporal summation occurred in that the contraction to several closely spaced taps was greater than to one. 3. 3. Tonic responses to hydrostatic pressure and to prolonged distension of oscula were seen. 4. 4. No action potentials could be detected by various types of external electrodes and in solutions of different conductivities. 5. 5. Contractions persisted undiminished when potassium concentration in the medium was increased by ten times in sea water or to 13–50 mM in fresh water. Omission of calcium, however, reversibly abolished responses. 6. 6. It is concluded that contractile cells of sponges give local, graded responses to mechanical stimuli, they may respond in depolarizing concentration of potassium, but require calcium.
Methylation of late adenovirus 2 nuclear and messenger RNA.

Abstract Methylation of adenovirus 2 (Ad 2) late RNA was studied. RNA was double-labeled with [3H-methyl]-methionine and [14C]-uridine 15–20 h postinfection. Nuclear RNA (rRNA) and cytoplasmic RNA (mRNA) was extracted, and fractionated into polyA(+) and (−) molecules using poly(U)-Sepharose. Ad 2 specific RNA was purified by 2 cycles of hybridization to and elution from Ad 2 DNA immobilized on filters. The Ad 2 polyA(+) and (−) nRNA and mRNA fractions had the same 3 H 14 C ratios, and were estimated to contain a minimum of 1.4 methylated nucleotides per 1000 bases. Viral RNA was digested with RNase T2 and chromatographed on DEAE-Sephadex in 7 M urea at pH 7.6. All four Ad RNA fractions contained methylated constituents consistent with: (1) two classes of methylated “capped” 5′-termini with general structures m7 GpppNmpNp and m7 GpppNmpNmpNp; (2) internal base methylations; (3) minor amounts of internal ribose 2′-0-methylations. Two classes of 5′-termini have previously been reported for animal cell mRNA, but not for mRNA from a variety of viruses. Internal methylations may be unique to RNA molecules transcribed in the nucleus, since they have not been found in RNA from cytoplasmic viruses. No gross differences were observed in the DEAE-Sephadex elution profiles of the methylated constituents of the four types of Ad 2 RNA. These results suggest that the majority of methylation events occur in the nucleus, and raise the possibility that Ad 2 methylated late nRNA may differ significantly from SV40 late nRNA (Lavi, S., and Shatkin, A.J. (1975) Proc. Natl. Acad. Sci. USA 72 , 2012–2016).
Personal and Professional Problems of Elementary School Teachers

DURING THE 1952 summer school session two groups of elemen tary school teachers were asked to designate on a check-list of 51 prob lems which ones they found to be serious, which of some concern and which of practically no importance. Their answers were to apply only to their present teaching situation. One of the groups included 148 teachers, 38 men and 110 women, attending the summer session of the State University Teachers College, Oswego, New York. The second group numbered 23 teachers, 12 men and 11 women, attending the sum mer session at the Appalachian State Teachers College in Boone, North Carolina. The 51 problems on the check-sheet were selected by the writers as being of considerable importance to teachers on the basis of their own experience as classroom teachers and as instructors in teachers colleges. In interpreting the results it should be noted that only 44 of the 51 problems would apply to all in the teacher group. The following problems concerned sub-groups within the main group: domestic obli gations of married teachers; family responsibilities of single teachers; problems due to advanced age; personal problems due to extreme youth; problems arising from being a minority group member in the commun ity; teaching problems due to advanced age; and teaching problems arising from being a minority group member. Table I gives the rank order of the problems of the total group of 171 teachers. In calculating rank order a problem listed by a teacher as serious was given twice the weight of one checked as being of some, but not great, concern. Table II shows the comparative rank order of men and women teachers and Table in of southern and northern teachers. Table IV shows the per cent of teachers in the total group, and also by sex and by section of the country, encountering each problem. The "S" column relates to per cent of the group considering each prob lem serious, the "L" column of some, but not great concern.
A framework for software safety verification of industrial robot operations

Abstract The role of safety of machines and operators in advanced automation and robotics is emphasized. The dominance of software in controlling robotic operations requires a systematic analysis for software safety and verification. Past research in this area shows lack of a modeling framework by which safety applications can be implemented. The present paper explains a design framework for the software safety module for industrial probotic operations. The module proposed includes preconditions and postconditions for each robot action based on a static model of the robot physical configurations and the environment. A generic software safety verification and encoding is presented for safety-critical actions of the robot. The software safety criteria and verification language is presented.
Aggregate-level predictors of the prevalence of selected drinking patterns in multiple studies : A research synthesis from the collaborative alcohol-related longitudinal project

This paper examines the prevalence of two “at-risk” alcohol drinking patterns (infrequent heavy drinking and frequent heavy drinking) within age/gender groups in multiple general population studies. When heterogeneity in findings across studies is found, we test the hypotheses that suicide, divorce, unemployment rates, and the per capita consumption of alcohol in each country are associated with the prevalence of these drinking patterns. These analyses should inform the literature on the relationships between societal factors and the prevalence of persons in different societies and periods in history that drink at these levels. [Translations are provided in the International Abstracts Section of this issue.]
Cross-cultural validity of the Miami Structured Interview--1 for type A in children: the American-Hellenic Heart Study.

The Miami Structured Interview—1 was developed (1) to assess Type A behavior in a broader age range of children than tested with previous interviews, and (2) for cross-cultural studies. This study examined the validity of the Miami Structured Interview—1 for assessing Type A behavior in 507 American and Greek preadolescent (ages 7–11) and adolescent (ages 12–16) boys. The interview was scored on voice stylistics such as speed of speech, word emphasis, and latency of response. Validity was tested using the Matthews Youth Test for Health (MYTH), a teacher rating scale of Type A behaviors. Interview determined Type A's received significantly higher MYTH scores than non Type A's for American adolescents (p < 0.05), Greek preadolescents (p < 0.01), and Greek adolescents (p < 0.05). The interview also identified extreme groups of Type A's and Type B's for American adolescents (p < 0.01) and Greek preadolescents (p < 0.05). The findings support the cross-cultural validity of the Miami Structured Interview—1 and the Type A construct for children. Limitations of the Miami Structured Interview—1 are discussed.
MO-C-BRE-01: The WMIS-AAPM Joint Symposium: Advances in Molecular Imaging

This joint symposium of the World Molecular Imaging Society (WMIS) and the AAPM includes three luminary speakers discussing work in new paradigms of molecular imaging in cancer (Contag), applications of optical imaging technologies to radiation therapy (Pogue) and an update on PET imaging as a surrogate biomarker for cancer progression and response to therapy. Learning Objectives: 1. Appreciate the current trends in molecular and systems imaging. 2. Understand how optical imaging technologies, and particularly Cerenkov detectors, can be used in advancing radiation oncology. 3. Stay current on new PET tracers - and targets - of interest in cancer treatment.
The African Challenge to Philosophical Paradigm: The Need for a Paradigm Shift in the Social, Economic, and Political Development of Africa

The theme for the 1997 African Studies Annual (ASA) Meeting, the first 40 years and beyond, is probably the most important historical calling for all members. In retrospect, it will help Africa, Africans, and Africanists to closely examine the past and reflect on the future social, political, and economic conditions of the continent. This work is the assessment of the past and some reflection on the future of Africa and begins with three related premises. First, ASA has recognized the need for developing the African philosophical paradigm as part of its intellectual discourse; the author hopes this will help one not only to reflect on the future but also to understand the tacit logic of historical thought. Second, this logic may also help raise the consciousness with regard to Africa's past, present, and future social development. Third, the historical and the level of awareness will help develop a theoretical framework for the purposeful application of the paradigm. Based on the premises given here, the question of the philosophical paradigm will be briefly discussed. The old paradigm and some models will be examined to help develop and articulate the
On the analysis of grain size in bulk nanocrystalline materials via x-ray diffraction

The Warren-Averbach (WA) analysis and other simplified methods that are commonly used to determine the grain size of nanocrystalline materials are discussed in terms of accuracy and applicabilities. The nanocrystalline materials used in the present study are prepared by cryomilling of A1 powders and subsequent consolidation (hot isostatic pressing and extrusion). Transmission electron microscopy observations of the as-extruded nanocrystalline A1 reveal a bimodal distribution of grain sizes centered around 50 to 100 nm and 250 to 300 nm. It is shown that the grain size determined by the WA analysis agrees with the lower bound grain size (e.g., 50 to 100 nm) observed experimentally. In the case of the integral method, it is useful to use a parabolic (Cauchy-Gaussian (CG)) relationship to approximate instrumental broadening and separate the intrinsic broadening. Compared to the Cauchy-Cauchy (CC) and Gaussian-Gaussian (GG) approximations, this is shown to give the best results. In addition, the reliability of the Scherrer equation is also discussed.
On the penetration of the solar wind into the cometary ionosphere

Questions of interaction between the cometary ionosphere and the solar wind are considered, taking into account present steady-state models of the global flow pattern. The stability of the ionopause and the feasibility of its penetration by the solar wind magnetic field and plasma are found to be central factors in connection with a consideration of the flow patterns. An investigation is conducted regarding a magnetic field penetration of the ionopause. It is concluded that a 'magnetic barrier' is expected to form ahead of the cometary ionopause. The stability of the ionopause is studied in some detail, taking into consideration a four-component fluid (neutrals, ions, protons, and electrons). The present study leads to the conclusion that any deep penetration of the solar wind magnetic field into the cometary ionosphere should be due to the Kelvin-Helmholtz instability of the ionopause, rather than due to the continuous diffusion process recently proposed by Marochnik (1982).
Identification of human alcohol dehydrogenase isozymes by disc polyacrylamide gel electrophoresis in 7 m urea

Abstract Polyacrylamide gel electrophoresis in the presence of 7 m urea provides a simple, reproducible method for the identification of cathodic alcohol dehydrogenase (ADH) isozymes. Treatment of native ADH dimers with 7 m urea and 1 m m dithiothreitol results in a complete dissociation of the 40,000 M r subunits. Electrophoresis of urea-dissociated ADH isozymes yields a single protein band for homodimers and two bands of equal intensity for heterodimers. The ADH subunits π, α, γ 2 , γ 1 and β exhibit electrophoretic mobilities of 0.71, 0.79, 0.88, 0.95, and 1.0, respectively. Thus, the identity of any cathodic ADH isozyme can be determined from the electrophoretic mobilities of its component subunits.
Microvia formation with lasers

Laser drilling has emerged in the last five years as the most widely accepted method of creating microvias in high-density electronic interconnect and chip packaging devices. Most commercially available laser drilling tools are currently based on one of two laser types: far-IR CO2 lasers and UV solid-state lasers at 355 nm. While CO2 lasers are recognized for their high average power and drilling throughput, UV lasers are known for high precision material removal and their ability to drill the smallest vias, with diameters down to about 25 –30 micron now achievable in production. This paper presents an overview of techniques for drilling microvias with the lasers.
Oceanic conditions in the eastern equatorial Pacific during the onset of ENSO in the Holocene

Records from South America show that modern ENSO (El Nino-Southern Oscillation) did not exist 7000 cal yr B.P. and has developed progressively since then. There has been little information available on oceanic conditions in the eastern equatorial Pacific (EEP) to constrain explanations for ENSO onset. We report quantitative observations on thermocline and mixed-layer conditions in the EEP during ENSO start up. We found important changes in both the thermocline and the mixed layer, indicating increased upwelling of cooler waters since 7000 cal yr B.P. This resulted from change in the source and/or properties of waters supplying the Equatorial Undercurrent, which feeds upwelling along the equator and the Peru margin. Modeling shows that ENSO is sensitive to subsurface conditions in the eastern equatorial Pacific and that the changes in the thermocline we observed were driven by extratropical processes, giving these a role in conditioning the development of ENSO. This is in contrast to models that call for control of equatorial Pacific oceanography by tropical processes only. These infer stronger upwelling and cooler surface waters for the EEP during the mid-Holocene, which is not supported by our results.
Enhanced endothelium-derived relaxing factor activity in pregnant, spontaneously hypertensive rats.

Abstract Pregnancy is normally associated with vasodilation that, in hypertensive animals such as the spontaneously hypertensive rat, causes a profound decrease in blood pressure. To test the possibility that enhanced basal endothelium-derived relaxing factor activity has a role in the vasodilation of pregnancy, we measured the changes in mean arterial pressure and heart rate induced by N G -monomethyi-L-arginine, a specific inhibitor of endothelium-derived relaxing factor synthesis, in conscious nonpregnant and pregnant (postmating day 20 to 21) normotensive Wistar-Kyoto and spontaneously hypertensive rats. N G -monomethyi-L-arginine caused similar dose-dependent increases in mean arterial pressure in nonpregnant and pregnant Wistar-Kyoto rats, but the accompanying decrease in heart rate was significantly greater in nonpregnant rats than in pregnant ones. In the spontaneously hypertensive rats, N G -monomethyi-L-arginine caused significantly greater dose-dependent increases in mean arterial pressure in pregnant compared with nonpregnant rats; there were no differences in the decreases in heart rate. These pressor responses were partially reversed by excess L-arginine but not D-arginine. Indomethacin had no effect on the pressor response to N G -monomethyi-L-arginine or the depressor response to L-arginine after N G -monomethyi-L-arginine. Therefore basal endothelium-derived relaxing factor plays a role in vascular tone and blood pressure regulation in vivo, and pregnancy may be associated with enhanced basal endothelium-derived relaxing factor activity in the hypertensive spontaneously hypertensive rats.
Solvable model of the quantum spin glass in a transverse field.

The spin-glass model with p-spin interactions in the presence of a transverse field is solved in the limit p\ensuremath{\rightarrow}\ensuremath{\infty}. The phase diagram is obtained and consists of three phases: A spin-glass phase and two paramagnetic phases. The paramagnetic phases are distinguished by transverse ordering. The spin-glass phase is similar to that of the random-energy model.
Reduced winter snowfall damages the structure and function of wintergreen ferns

• Premise of the study: The full impact of climate change on ecosystems and the humans that depend on them is uncertain. Anthropogenic climate change is resulting in winters with less snow than is historically typical. This deficit may have an impact on wintergreen ferns whose fronds lie prostrate under the snowpack and are thereby protected from frost.• Methods: Frost damage and ecophysiological traits were quantified for three species of wintergreen fern (Dryopteris intermedia, Dryopteris marginalis, and Polystichum acrostichoides) near Delhi, NY following the winters of 2012 (which had very little snowfall) and 2013 (which had typical snowfall).• Key results: Dryopteris intermedia was the most common species and had the highest percentage of frost-damaged fronds and the highest percentage of its cover damaged in 2012. Frost damage was significantly less in 2013 for all species. Polystichum acrostichoides had the highest vernal photosynthetic rate in undamaged fronds, and all three species had a negative net photosynthetic rate in frost-damaged fronds. The wintergreen fern community lost 36.69 ± 2.80% of its productive surface area to frost damage in 2012. Dryopteris intermedia had the thinnest leaves and this trait may have made it the most susceptible to frost damage.• Conclusions: These results demonstrate that repeated winters of little snow may have a significant impact on the structure and functioning of the wintergreen fern community, and species will respond to a reduced snowpack on an individual basis.
Effects of oral experience on rewarding properties of oral stimulation

The oropharyngeal sensory and motor experiences of ingestion have long been considered to be rewarding or motivating. Recent work has suggested that the reinforcing properties of oral stimulation are modulated by experience with an ingestive bout. Two processes that result from the repeated oral experience that occurs during an ingestive bout, sensitization and oral habituation, may influence the reinforcing or rewarding properties of oral stimulation. The first process, sensitization, describes an initial increase in responsiveness following the first presentation of a stimulus: such an increase in responding has been noted in the ingestive behavior of both rats and humans. The second process, oral habituation, occurs after sensitization of responding, and results from continued repeated exposure to oral stimulation. During oral habituation, ingestive responsiveness declines; decreased ingestive responding to oral stimulation is demonstrated even in the absence of substantial post-ingestive signals. Both oral habituation and sensitization reflect process through which experience may modulate the rewarding properties of oral stimulation.
A Functional Guide to the Evidence-Based Practice Movement in the Substance Abuse Treatment Field

As a matter of policy, public and private purchasers of substance abuse treatment services are requiring the use of evidence-based practices (EBPs) in mental health and substance abuse treatment programs. Social work practitioners and agency leaders should be familiar with EBPs specific to substance abuse treatment as they regularly serve individuals with substance use disorders. The goals of this article are to (a) provide a rationale for the movement toward EBPs in substance abuse treatment; (b) compare evidentiary standards for EBPs; (c) familiarize leaders of substance abuse treatment agencies with available resources on EBPs; (d) discuss the role of the single-state agency for substance abuse services (SSA) in creating a culture that supports the development, adoption, implementation and evaluation of EBPs; and (e) highlight the variables that influence the implementation of EBPs on an agency level.
Conservation of telomere protein complexes: shuffling through evolution.

The rapid evolution of telomere proteins has hindered identification of orthologs from diverse species and created the impression that certain groups of eukaryotes have largely non-overlapping sets of telomere proteins. However, the recent identification of additional telomere proteins from various model organisms has dispelled this notion by expanding our understanding of the composition, architecture and range of telomere protein complexes present in individual species. It is now apparent that versions of the budding yeast CST complex and mammalian shelterin are present in multiple phyla. While the precise subunit composition and architecture of these complexes vary between species, the general function is often conserved. Despite the overall conservation of telomere protein complexes, there is still considerable species-specific variation, with some organisms having lost a particular subunit or even an entire complex. In some cases, complex components appear to have migrated between the telomere and th...
Radioenzymatic microassay for picogram quantities of serotonin or acetylserotonin in biological fluids and tissues

This paper describes several modifications of the original radioenzymatic assay for serotonin which increase the sensitivity of the assay 20-fold as well as enhance its reliability. Using this method serotonin concentrations can be directly measured in biological examples without precleaning the sample. When compared to currently available methods this assay is specific and sensitive to approximately 1 pg of serotonin and can be used to measure serotonin levels in individual brain nuclei or microliter quantities of biological fluids. This assay can be easily adapted for the direct measurement of N-acetylserotonin. A large number of samples can be assayed in a single working day.
Cardiomegaly in neonatal rats exposed to 500 ppm carbon monoxide.

Increased hemodynamic workload was induced in growing neonatal rats to study alterations in myocyte structure and number and to determine if carbon monoxide (CO) produced a volume-induced model of cardiomegaly. Newborn rats were exposed to 500 ppm CO for up to 32 days of age, at which time the remaining CO exposed rats and ambient air controls continued development in room air to 200 days of age. In the CO group, ventricular weight to body weight ratio was 26% greater than controls at 6 days of age, more than double at 15 days, and remained 47% greater at 28 days. Although absolute myocyte volumes were not different between the two groups at any time period, the CO group did have greater myocyte volume relative to body weight during the CO exposure period. Binucleated myocytes of both ventricles were longer than controls during the exposure period, but did not have increased width. By 200 days of age, myocytes from left ventricle plus septum of CO exposed rats were significantly shorter and CO exposed rats had more total myocytes than controls (36 × 106 versus 32 × 106 for controls, P < 0·05). In this study, cardiomegaly induced by 500 ppm CO from birth to 32 days of age was primarily due to myocyte hypertrophy with myocytes having increased length to width ratios (i.e., alterations consistent with a volume-induced model). Following removal from CO exposure, there was regression of both cardiomegaly and myocyte hypertrophy. With increasing time after removal from CO, myocytes tended to become shorter and smaller compared to age matched controls. This trend was present at 105 days and statistically significant by 200 days of age, resulting in an increased number of myocytes in the myocardium long after removal of rats from CO exposure. We conclude that neonatal exposure to CO causes cardiomegaly by increase in cell length and cell volume, consistent with a volume overload model of cardiac hypertrophy.
Formation Detection with Wireless Sensor Networks

We consider the problem of detecting the formation of a set of wireless sensor nodes based on the pairwise measurements of signal strength corresponding to all transmitter/receiver pairs. We assume that formations take values in a discrete set and develop a composite hypothesis testing approach which uses a Generalized Likelihood Test (GLT) as the decision rule. The GLT distinguishes between a set of probability density function (pdf) families constructed using a custom pdf interpolation technique. The GLT is compared with the simple Likelihood Test (LT). We also adapt one prevalent supervised learning approach, Multiple Support Vector Machines (MSVMs), and compare it with our probabilistic methods. Due to the highly variant measurements from the wireless sensor nodes, and these methods' different adaptability to multiple observations, our analysis and experimental results suggest that GLT is more accurate and suitable for formation detection. The formation detection problem has interesting applications in posture detection with Wireless Body Area Networks (WBANs), which is extremely useful in health monitoring and rehabilitation. Another valuable application we explore concerns autonomous robot systems.
Experimental aerodynamic characteristics of an NACA 0012 airfoil with simulated ice

An experimental program was conducted with an NACA 0012 airfoil to investigate the effect of Reynolds number on the aerodynamic coefficients with and without a leading-edge simulated ice shape. Six Reynolds numbers from 0.36 to 3.36 x 106 were investigated at both positive and negative angles of attack through stall. Values of ACd, AQ, ACF , and ACm were measured for the no-ice/generic-ice airfoil configurations. The experimental values have shown that the addition of the generic ice shape causes premature stall with a considerable reduction in C, and stall angle of attack; an increase in the drag values of 120-200% compared to the clean airfoil values; and a significant increase in Cmcl4 resulting in positive values of dCm /dQ. However, the aerodynamic coefficients of the airfoil with the leading-edge simulated ice showed little dependence on Reynolds number throughout the range tested, unlike that of the clean airfoil configuration.
A Hybrid Clustering Algorithm Based on Rough Set and Shared Nearest Neighbors

In this paper, a hybrid method combining rough set and shared nearest neighbor algorithms is proposed for data clustering with non-globular shapes. The rough k-means algorithm is based on the distances between data and cluster centers. It partitions a data set with globular shapes well, but when the data are non-globular shapes, the results obtained by a rough k-means algorithm are not very satisfactory. In order to resolve this problem, a combined rough set and shared nearest neighbor algorithm is proposed. The proposed algorithm first adopts a shared nearest neighbor algorithm to evaluate the similarity among data, then the lower and upper approximations of a rough set algorithm are used to partition the data set into clusters.
Excimer laser ablation and etching

The characteristics of excimer lasers and the nature of ablation and etching processes are described. The two kinds of laser ablation mechanisms, thermal and electronic, are discussed. Thermal processes all rely on an intense laser pulse to heat a surface very rapidly. Electronic mechanisms do not rely on heating. Two of these quantum-type processes have been discussed widely. In the first, laser photons directly excite and break the bonds of the solid, causing ejection of material. In the second, photoexcitation creates electron-hole pairs, the potential energy of which can be coupled directly into kinetic energy of the atoms via a radiationless process. The energized atoms are able to overcome the surface binding energy, and again material is ejected. Pulsed laser etching has many of the same physical-interaction mechanisms as laser ablation but requires an active chemical medium to be in contact with the solid because laser-induced chemical reactions serve as the driving force for material removal. Issues that must be addressed prior to the successful implementation of an excimer-laser fabrication tool are discussed. The use of patterned beams for direct patterning of surfaces is considered. Microelectronic applications suitable for excimer-laser ablation and etching are examined. >
The temporal relationship between joints and faults

Abstract Examples are presented of three temporal relationships between joints and faults: joints that pre-date faults; joints that are precursors to, or synchronous with, faults; and joints that post-date faults. Emphasis is placed on strike-slip faults in carbonate beds, but other examples are used. General rules are given for identifying the three temporal relationships between joints and faults. Joints that formed before faults can be dilated, sheared or affected by pressure solution during faulting, depending on their orientation in relation to the applied stress system. Faulted joints can preserve some original geometry of a joint pattern, with pinnate joints or veins commonly developing where faulted joints interact. Joints formed synchronously with faults reflect the same stress system that caused the faulting, and tend to increase in frequency toward faults. In contrast, joints that pre- or post-date faults tend not to increase in frequency towards the fault. Joints that post-date a fault may cut across or abut the fault and fault-related veins, without being displaced by the fault. They may also lack dilation near the fault, even if the fault has associated veins. Joints formed either syn- or post-faulting may curve into the fault, indicating stress perturbation around the fault. Different joint patterns may exist across the fault because of mechanical variations. Geometric features may therefore be used in the field to identify the temporal relationships between faults and joints, especially where early joints affect or control fault development, or where the distribution of late joints are influenced by faults.
DNA amplification in arsenite-resistant Leishmania

Abstract Arsenite-resistant variants of a trypanosomatid protozoan, Leishmania mexicana amazonensis , were selected in vitro by stepwise increases of sodium arsenite concentrations up to 30 μ M in the culture medium. These variants were found to contain amplified DNA as extrachromosomal supercoiled molecules of about 69 kb. They originate from a single chromosome in the wild-type cells. There is evidence of chromosomal changes in these cells associated with the selection for arsenite resistance. The apparent absence of these circular molecules in the wild type and their loss from the drug-sensitive revertants suggest amplification of chromosomal DNA into these extrachromosomal circles as the mechanism of arsenite resistance.
Si incorporation probabilities and depth distributions in Ga1−xAlxAs films grown by molecular‐beam epitaxy

The Si incorporation probability σSi of Si and the segregation‐induced broadening Δs of nominally abrupt Si doping modulations during the deposition of Ga1−xAlxAs films grown by molecular‐beam epitaxy (MBE) have been measured as a function of film growth temperature Ts, alloy composition x and As2 overpressure. Si depth distributions were obtained using secondary ion mass spectrometry (SIMS) calibrated with internal standards. The inherent broadening due to the SIMS sputter profiling Δ0 was ∼6.5±1 nm. Dopant modulations generated by abrupt changes in the incident Si flux were found to exhibit broadening which varied, after subtracting the instrumental effects, from Δs≂7 nm at 600 °C to 25 nm at 725 °C. Thus, Si segregation during Ga1−xAlxAs MBE, while quite small compared to other dopants such as Sn, was still measurable. The fact that Δs increased with increasing Ts indicates that the segregation rate was kinetically limited over the temperature range investigated in these experiments. There was a slight...
Ventriloquating the Meanings of Mathematics

ABSTRACT Recent calls for reform in mathematics education have focused on enriching teacher knowledge and classroom activity to make students more active participants in the construction of knowledge. This approach underestimates the power of institutional histories to frame participants’ views of schooling. In particular, it ignores the perspectives students and parents bring to reforms that are often implemented in their schools without their knowledge or assent. In this paper, we explore how parents and students construct meanings of new instructional organization and activities, particularly as they use experience to understand the changes imposed in the name of reform. We argue that the meaning of mathematics as a differentiating mechanism, which reform practices are meant to transform, was used differentially by participants as they responded to reform. Further, we examine how the meaning made by students were very similar to those voiced by parents. We use Bakhtin's notion of ventriloquation which ...
Composition of Trace Alkaloids in Tobacco Leaf Lamina

Changes were investigated in trace alkaloid composition of MC-1 (bright) and Burley-21 (burley) leaf lamina during curing. Seventeen alkaloids were identified. The total level of trace alkaloids decreased by approximately 60% in both MC-1 (flue-cured) and Burley-21 (air-cured). Although the level of most alkaloids also decreased, 2,3´-bipyridyl and four nornicotine derivatives, i.e. N´-hexanoyl-, N´-octanoyl-, 1´-(6-hydroxyoctanoyl)- and 1´-(7-hydroxyoctanoyl)-nornicotine, increased during curing in both varieties. Differences in the trace alkaloid composition of cured leaf lamina among MC-1 (bright), Burley-21 (burley) and Basma (Orient) were also studied. In all varieties, N´-formylnornicotine, nicotyrine, anabasine and cotinine were present at high concentrations relative to the other trace alkaloids. The alkaloids which were present in a relatively high concentration in particular varieties, were as follows: MC-1; N´-formylanabasine, Burley-21; N´-hexanoyl- and N´-octanoyl-nornicotine, and Basma; coti...
Diurnal Patterns of Soluble Amyloid Precursor Protein Metabolites in the Human Central Nervous System

The amyloid-β (Aβ) protein is diurnally regulated in both the cerebrospinal fluid and blood in healthy adults; circadian amplitudes decrease with aging and the presence of cerebral Aβ deposits. The cause of the Aβ diurnal pattern is poorly understood. One hypothesis is that the Amyloid Precursor Protein (APP) is diurnally regulated, leading to APP product diurnal patterns. APP in the central nervous system is processed either via the β-pathway (amyloidogenic), generating soluble APP-β (sAPPβ) and Aβ, or the α-pathway (non-amyloidogenic), releasing soluble APP-α (sAPPα). To elucidate the potential contributions of APP to the Aβ diurnal pattern and the balance of the α- and β- pathways in APP processing, we measured APP proteolytic products over 36 hours in human cerebrospinal fluid from cognitively normal and Alzheimer's disease participants. We found diurnal patterns in sAPPα, sAPPβ, Aβ40, and Aβ42, which diminish with increased age, that support the hypothesis that APP is diurnally regulated in the human central nervous system and thus results in Aβ diurnal patterns. We also found that the four APP metabolites were positively correlated in all participants without cerebral Aβ deposits. This positive correlation suggests that the α- and β- APP pathways are non-competitive under normal physiologic conditions where APP availability may be the limiting factor that determines sAPPα and sAPPβ production. However, in participants with cerebral Aβ deposits, there was no correlation of Aβ to sAPP metabolites, suggesting that normal physiologic regulation of cerebrospinal fluid Aβ is impaired in the presence of amyloidosis. Lastly, we found that the ratio of sAPPβ to sAPPα was significantly higher in participants with cerebral Aβ deposits versus those without deposits. Therefore, the sAPPβ to sAPPα ratio may be a useful biomarker for cerebral amyloidosis.
Lung primary primitive neuroectodermal tumor in an adult patient

A 53-year-old Caucasian male was evaluated for cough and exertional dyspnea. His past medical history was significant for heavy cigarette smoking and recurrent pneumonias. CT scan of the chest performed in January 2007 revealed multiple, sub-centimeter, calcified and non-calcified pulmonary nodules those were stable when compared to a scan done in May of 2005. However, a new 6mm non-calcified nodule was noted in the right lower lobe (Figure 1(A)). In June 2007, a repeat CT scan of the chest demonstrated enlargement of the nodule to a diameter of 2.5 cm (Figure 1(B)). Three weeks later, PET-CT showed high uptake within the mass (standardized uptake value maximum of 15.6) with a new subjacent nodule measuring 1.2 2.0 cm and no evidence of distal metastases (Figures 1(C) and (D)).
Deficiency of monoclonal antibody-defined NK Cells (HNK-1+) in primary immunodeficiency disorders.

Abstract Natural killer (NK) cells were enumerated in the peripheral blood mononuclears from 13 patients with primary immunodeficiency disease, using recently developed monoclonal antibody, Leu 7 (HNK-1). Eight of 13 patients demonstrated quantitative deficiency of NK cells when compared to simultaneously studied healthy controls, using monoclonal antibody and fluorescence-activated cell sorter (FACS). The quantitative deficiency of NK cells could be one of several factors responsible for increased susceptibility to infections and increased incidence malignancies in patients with primary immunodeficiencies.
Microwave characterization of slot line and coplanar strip line on high-resistivity silicon for a slot antenna feed network

This article presents the effective dielectric constant (ϵeff) and attenuation constant (α) of an unshielded slot line and a coplanar strip line on a high-resistivity (5000–10,000 ω-cm) silicon wafer. The ϵeff (dc to 40 GHz) and α (dc to 26.5 GHz) in each case are determined from the measured resonant frequencies and insertion loss of a ring resonator. The measurements are carried out at room temperature. No dc bias is applied to the transmission lines. The attenuation for slot line and coplanar stripline on silicon are compared with microstrip line and coplanar waveguide on other semiconductor substrate materials. Lastly, a microstrip-to-slot-line transition and its use in a feed network for linearly tapered slot antennas is demonstrated. © 1994 John Wiley & Sons, Inc.
Integrated analysis of residue coevolution and protein structure in ABC transporters.

Intraprotein side chain contacts can couple the evolutionary process of amino acid substitution at one position to that at another. This coupling, known as residue coevolution, may vary in strength. Conserved contacts thus not only define 3-dimensional protein structure, but also indicate which residue-residue interactions are crucial to a protein’s function. Therefore, prediction of strongly coevolving residue-pairs helps clarify molecular mechanisms underlying function. Previously, various coevolution detectors have been employed separately to predict these pairs purely from multiple sequence alignments, while disregarding available structural information. This study introduces an integrative framework that improves the accuracy of such predictions, relative to previous approaches, by combining multiple coevolution detectors and incorporating structural contact information. This framework is applied to the ABC-B and ABC-C transporter families, which include the drug exporter P-glycoprotein involved in multidrug resistance of cancer cells, as well as the CFTR chloride channel linked to cystic fibrosis disease. The predicted coevolving pairs are further analyzed based on conformational changes inferred from outward- and inward-facing transporter structures. The analysis suggests that some pairs coevolved to directly regulate conformational changes of the alternating-access transport mechanism, while others to stabilize rigid-body-like components of the protein structure. Moreover, some identified pairs correspond to residues previously implicated in cystic fibrosis.
Experimental study of the diffusion-controlled acid degradation of Class H Portland cement

Abstract The rate of acid corrosion of Class H Portland cement was measured using time-lapse video over a range of temperature ( T = 30–80 °C) and pH (0–3.7), both for hydrochloric acid and carbonic acid. The process was found to be diffusion-controlled, and the dependence of the slope, S , of corrosion depth vs square root of time was obtained as a function of T and pH. The slope decreases by about a factor of 3, if the leachate is allowed to accumulate on the corroded surface; however, a flow rate as low as 4 cm/h is sufficient to flush the surface and establish an equilibrium rate. With or without accumulation of leachate, the cumulative cation mass loss is proportional to the depth of leaching, indicating that the phases extracted are very similar in both cases. The corrosion rate between 30 and 80 °C is characterized by an activation energy of 39.6 kJ/mol and a power-law dependence on acid concentration, S ∼ [H + ] 0.35 . The resulting equation describes the present results, and agrees within a factor of 2 with rates reported in the literature by other workers. On the basis of this equation, estimates are provided of the leakage rates from a reservoir that is sealed with a sound plug of cement (where escape of the acid would take millions of years) or where an annular gap extends through the caprock. In the latter case, corrosion in small annuli (≤10 μm diameter) is predicted to be concentrated near the bottom (i.e., near the reservoir-caprock boundary), so that penetration of acid into the overlying formation will take centuries.
Equivalent path lengths in an integrating cavity: comment.

The equivalent absorption path length in an integrating cavity is examined. In an otherwise excellent paper, Tranchart et al. [Appl. Opt.35, 7070 (1996APOPAI0003-693510.1364/AO.35.007070] made an important error in obtaining the expressions for the equivalent path length in an integrating cavity. This error has been propagated through several other publications in the literature. Since the equivalent path length is the sine qua non for obtaining an accurate absorption coefficient when using an integrating cavity, it is our intent here to give the correct formulas to prevent further errors when extracting absorption coefficients.
Synthesis of (-)-reiswigin A. Assignment of absolute and relative configuration

Abstract The synthesis of the anti-viral agent (-)-reiswigin A ( 1 ) was accomplished in 8 steps in 7% overall yield. The absolute stereochemistry and configuration of the side chain methyl group of the natural product were assigned as shown in 17 .
Embryotoxicity and teratogenicity of Cis-diamminedichloroplatinum.

Cis-diamminedichloroplatinum has lethal, toxic and teratogenic effects on presomitic mouse embryos in doses that are not toxic to adult animals.
Ray-tracing-based reconstruction algorithms for digital breast tomosynthesis

As a breast-imaging technique, digital breast tomosynthesis has great potential to improve the diagnosis of early breast cancer over mammography. Ray-tracing-based reconstruction algorithms, such as ray-tracing back projection, maximum-likelihood expectation maximization (MLEM), ordered-subset MLEM (OS-MLEM), and simultaneous algebraic reconstruction technique (SART), have been developed as reconstruction methods for different breast tomosynthesis systems. This paper provides a comparative study to investigate these algorithms by computer simulation and phantom study. Experimental results suggested that, among the four investigated reconstruction algorithms, OS-MLEM and SART performed better in interplane artifact removal with a fast speed convergence.
Partial purification and characterization of guanine aminohydrolase fromtrypanosoma cruzi

Guanine deaminase (guanine aminohydrolase, EC 3.5.4.3) catalyzes the hydrolytic deamination of guanine to xanthine. A rapid procedure for the partial purification of guanine deaminase fromTrypanosoma cruzi using granulated bed electrofocusing was developed. Supernatants of cell sonicates (40,000 g) were subjected to electrofocusing with a broad range ampholyte (pH 4–9). Sections of the gel were eluted and assayed for xanthine production. Active fractions were pooled, concentrated, and again subjected to electrofocusing with a pH 5–7 range ampholyte. This procedure resulted in over 240-fold purification. The compounds 4-amino-5-imidazolecarboxamide andN6-methyladenine were found to be potent competitive inhibitors of the enzyme. Their respective Ki values were 3.5×10−6M and 9.5×10−6M. Irreversible inactivation of the enzyme was observed upon incubation withp-chloromercurophenylsulfonic acid andN-ethyl-maleamide at 5.0×10−4M. The enzyme was labile to heat; a substantial loss of activity occurred upon incubation at 55°C for 5 min. A broad pH range of activity (pH 7.5–8.5) was observed in Tris, citrate, and phosphate buffers.
Prophylactic Administration of Bacterially Derived Immunomodulators Improves the Outcome of Influenza Virus Infection in a Murine Model

Prophylactic or therapeutic immunomodulation is an antigen-independent strategy that induces nonspecific immune system activation, thereby enhancing host defense to disease. In this study, we investigated the effect of prophylactic immunomodulation on the outcome of influenza virus infection using three bacterially derived immune-enhancing agents known for promoting distinct immunological profiles. BALB/c mice were treated nasally with either cholera toxin (CT), a mutant form of the CT-related Escherichia coli heat-labile enterotoxin designated LT(R192G), or CpG oligodeoxynucleotide. Mice were subsequently challenged with a lethal dose of influenza A/PR/8/34 virus 24 h after the last immunomodulation treatment and either monitored for survival or sacrificed postchallenge for viral and immunological analysis. Treatment with the three immunomodulators prevented or delayed mortality and weight loss, but only CT and LT(R192G) significantly reduced initial lung viral loads as measured by plaque assay. Analysis performed 4 days postinfection indicated that prophylactic treatments with CT, LT(R192G), or CpG resulted in significantly increased numbers of CD4 T cells, B cells, and dendritic cells and altered costimulatory marker expression in the airways of infected mice, coinciding with reduced expression of pulmonary chemokines and the appearance of inducible bronchus-associated lymphoid tissue-like structures in the lungs. Collectively, these results suggest that, despite different immunomodulatory mechanisms, CT, LT(R192G), and CpG induce an initial inflammatory process and enhance the immune response to primary influenza virus challenge while preventing potentially damaging chemokine expression. These studies provide insight into the immunological parameters and immune modulation strategies that have the potential to enhance the nonspecific host response to influenza virus infection.
Growth rate stimulation of marine pseudomonads by thiosulfate.

The oxidation of thiosulfate to tetrathionate exerts a definite growth rate stimulation in glucose, acetate, and yeast extract cultures of some marine pseudomonads. The failure to find this effect in earlier studies with terrestrial isolates may lie in the particular conditions used in the present experiments (constant pH, high ratio of thiosulfate to organic substrate) or in the different metabolic characteristics of the marine isolates.