cssi/SciSciGPT-SciSciNet huggingface dataset:
Evidence that the 5'-untranslated leader of mRNA affects the requirement for wheat germ initiation factors 4A, 4F, and 4G.

Abstract The efficiency of translation of alfalfa mosaic virus (AMV) RNA 4, barley alpha-amylase (B alpha A) mRNA, and two chimeric mRNAs, AMV 4-B alpha A and B alpha A-AMV 4 (in which the 5' leader sequences of the two mRNAs were interchanged), was measured in an S30 extract from wheat germ and a fractionated system from wheat germ in which translation could be made dependent upon initiation factor (eIF) 3, 4A, 4F, or 4G. In the S30 system, AMV RNA 4 and the chimeric mRNA AMV 4-B alpha A are translated much more efficiently than B alpha A mRNA and the chimeric mRNA B alpha A-AMV 4. When the S30 system was supplemented with high amounts of purified eIF-3, eIF-4A, eIF-4F, and eIF-4G, B alpha A and B alpha A-AMV 4 mRNAs were translated as efficiently as AMV RNA 4 and AMV 4-B alpha A mRNA. These findings indicated that the mRNAs containing the B alpha A leader sequence required higher amounts of one or more of the initiation factors (eIF-3, eIF-4A, eIF-4F, and eIF-4G) for efficient translation. Determination of the amounts of the initiation factors required for translation in the fractionated system showed that AMV RNA 4 required 2-4-fold lower amounts of eIF-3, eIF-4A, eIF-4F, and eIF-4G than did B alpha A mRNA. Replacement of the B alpha A leader sequence with that of AMV RNA 4 decreased the amounts of eIF-4A, eIF-4G, and eIF-3 required, but did not affect the amount of eIF-4F required. Replacement of the AMV RNA 4 leader sequence with that of B alpha A mRNA increased the amounts of eIF-4F, eIF-4G, and eIF-3 required, but did not affect the amount of eIF-4A required. These data strongly suggest that the amounts of the factors required are affected not only by the 5' leader itself but also by interactions between the 5' leader and a region(s) of the mRNA 3' to the initiation codon.
The Safety of Navigation in the 18th Century French Cod Fisheries

Because of the importance of tropical areas of the world as a source of labour and commodities under the Ancien Regime, the historiography of French transoceanic trade and of the safety of navigation has been very much oriented towards the study of sailing and trading in a tropical environment. Relatively little attention has been paid to the substantial French transoceanic trade in areas of the world where safety conditions had very little in common with those in the West and East Indies. Indeed, neither the tropical trades nor the French Navy in wartime could have sustained themselves without the existence of other types of maritime trade. Reliable sources dealing with Saint-Malo and Granville, the two major French ports engaged in cod fishing, strongly suggest that before the 19th century, the French fishing industry in North America displayed a highly positive manpower gain/ loss ratio. Because this gave the cod fishing trade a significant role in ensuring a steady supply of men to the French Navy as well as to other trades, the French Crown always remained adamant at preserving French fishing privileges at Newfoundland.1
A new hybrid learning algorithm for drifting environments

An adaptive algorithm for drifting environments is proposed and tested in simulated environments. Two powerful problem solving technologies namely Neural Networks and Genetic Algorithms are combined to produce intelligent agents that can adapt to changing environments. Online learning enables the intelligent agents to capture the dynamics of changing environments efficiently. The algorithm's efficiency is demonstrated using a mine sweeper application. The results demonstrate that online learning within the evolutionary process is the most significant factor for adaptation and is far superior to evolutionary algorithms alone. The evolution and learning work in a cooperating fashion to produce best results in short time. It is also demonstrated that online learning is self sufficient and can achieve results without any pre-training stage. When mine sweepers are able to learn online, their performance in the drifting environment is significantly improved. Offline learning is observed to increase the average fitness of the whole population.
Formation of machine cells and part families in cellular manufacturing: a linear integer programming approach

A linear zero-one integer programming approach is proposed to solve the machine-cell/part-family formation problem for designing cellular manufacturing systems. Given a machine-part incidence matrix that contains process routing information, a similarity coefficient is derived for each pair of machines/parts. The proposed linear zero-one integer programming approach seeks to maximize similarity coefficients of machines/parts subject to an upper bound on the number of machines/parts in each machine cell/part family and a constraint on the number of machine cells/part families. The solutions to the machine-cell/part-family formation problem based on different definitions of similarity coefficients are discussed. >
Four-photon interference experiment and its implications for the Greenberger-Horne-Zeilinger theorem

Summary form only given. We report the latest experimental results on four-photon interference and discuss what they mean in terms of the GHZ theorem. The four-photon interference is the nonlocal effect proving the existence of the entangled (i.e., nonfactorizable) states of four photons. The entanglement of two photons emerging from a spontaneous parametric downconversion (SPDC) crystal is well studied. Particularly, for the type-II SPDC, when the signal and the idler photons are orthogonally polarized, it is possible to entangle them in both space and polarization. We take advantage of this to entangle two pairs of SPDC photons generated by two different, but coherently pumped, sources.
A multidimensional scaling analysis of phonemic responses from hard of hearing and deaf subjects of three languages.

Twenty logatoms (CVCV) involving five vowels and 20 consonants were presented to 36 subjects, 18 hard of hearing and 18 deaf. Of the 18 subjects, six were speakers of English (American), six Serbo-Croatian (Yugoslavian), and six French (French), The logatoms were analysed for both initial and medial consonants. The responses were recorded on magnetic tape and transcribed phonetically by three judges. The data were analysed by IND-SCAL and reported in unique dimension. Twelve groups of similarity matrices mainly yielded two- and three- dimensional solutions. The interpretations of these dimensions were mainly voicing and sibilant. Additional features retrieved in some cases included nasality, fricative, and others. Recovery of similar space for three language groups, two deviancy groups, and two positions reveal "universal" dimensionality and features of the consonants.
Temporal discrimination deficits as a function of lag interference in older adults

A vital component of episodic memory is the ability to determine the temporal order of remembered events. Although it has been demonstrated that the hippocampus plays a crucial role in this ability, the details of its contributions are not yet fully understood. One proposed contribution of the hippocampus is the reduction of mnemonic interference through pattern separation. Prior studies have used behavioral paradigms designed to assess this function in the temporal domain by evaluating the ability to determine the order of remembered events as a function of proximity in time. Results from these paradigms in older adults (OA) have been mixed, possibly due to limitations in controlling elapsed time and narrow range of temporal lags. Here, we introduce a novel behavioral paradigm designed to overcome these limitations. We report that OAs are impaired relative to younger adults at moderate and high temporal lags but not at low lags (where performance approached floor). We evaluated OAs' ability to benefit from primacy (enhanced order judgment on the first few items of any given sequence) and found two distinct subgroups: one group was on par with young adults [aged-unimpaired (AU)] and the other group was two standard deviations below the mean of young adults [aged-impaired (AI)]. Temporal discrimination performance in AU adults was consistent with a pattern separation deficit, while performance in AI adults was consistent with a generalized temporal processing deficit. We propose that the task introduced is a sensitive marker for episodic memory deficits with age, and may have diagnostic value for early detection of age-related pathology. © 2014 Wiley Periodicals, Inc.
Interventions with Students at Risk for Dropping Out of School: A High School Responds.

AbstractBecause the high school dropout rate in many school districts remains unacceptably high, school personnel are searching for effective programs to keep students in school. However, there have been few studies that describe school structures or their influence on students’ school status. The purpose of this study was to add to the available knowledge base on the impact of school structures on students. Data from field notes, interviews, and school records were used to describe and to discuss the effectiveness of interventions generated by one school committee. On the basis of the findings of this study, we encourage school personnel to use interventions available in high schools to prevent dropouts in a cost-effective manner.
The effects of gonadectomy on the sex differences in dietary self-selection patterns and carcass compositions of rats

Abstract The relationship of dietary self-selection patterns and carcass composition was studied in intact and gonadectomized male and female rats. Males consumed a significantly greater proportion of their diets as protein and had a greater proportion of their carcasses as fat than females. Gonadectomy increased the percentage protein selected by females to the level of intact males and altered the proportions of the carcass tissues to the levels of these males. The results were discussed in terms of the regulatory consequences of varying nutritional intake patterns and the role of female sex hormones in the regulation of body weight and composition.
Forecasting the Dissipation of Fog and Stratus Clouds

F the time at which fog or stratus clouds will break has become a particularly important problem in recent years with the development of commercial and military aviation and the improved methods of flying which have resulted. Many times the completion of an airline schedule is dependent upon the dissipation of a fog or low cloud deck within a given time. Even the rate at which the ceiling is rising becomes important, for may flights could be dispatched toward fog-bound terminals without long delays if a definite indication of sufficient improvement were available. At present, forecasts involving these elements are largely a function of the forecaster's experience, and are not always extremely accurate or reliable. Various empirical methods employing such elements as the thickness of the cloud, the height of the cloud base, and the fact that terrestrial radiation is completely absorbed by the lower levels of the clouds, appear to have formed the principal aids to forecasting the breaking of fog and stratus systems. The absorption of terrestrial radiation has been generally credited as the source of heat providing for the dissipation of a cloud, since the process normally takes place upward from the cloud base. A moment's thought will convince one that this factor cannot be of very great importance. Brunt has shown that the radiative transfer of heat in the atmosphere in regions of the spectrum where water vapor is the effective absorbing agent, is negligible. This means that any net gain of heat at a cloud base by radiation must originate in the transparent regions of the spectrum, a series of bands accounting for only about 25% of the total. This gain is further reduced by the fact that a cloud acts as a black body, and therefore the sky radiation on a cloudy day cannot differ greatly from that originating at the earth's surface, especially if the cloud is low and its temperature nearly the same as that of the ground beneath. Hence, it seems illogical to assume that cloud decks several thousand feet in thickness may be dissipated within a few hours by heat gained from the absorption of terrestrial radiation.
Results of X-band electronically scanned array using an overlapped subarray architecture

The measured results from an X-band electronically scanned array using an overlapped subarray architecture are presented. The 2D architecture uses a 12×12 element subarray with 3 to 1 overlapping. The active electronic scanned array is a receive only implementation consisting of switch, low noise amplifier, phase shifter and attenuator. Measured far-field patterns and excitation at the aperture using near-field scanner demonstrates desired design goals of a 20 degree sector beam with low sidelobes. Finally, the scan performance of the sector subarray beam is measured at 20 and 40 degrees. A three tile implementation is constructed and measured.
A Biopsychosocial Model for the Management of Patients With Sickle-Cell Disease Transitioning to Adult Medical Care

The lifespan of patients with sickle-cell disease (SCD) continues to increase, and most affected individuals in high-resource countries now live into adulthood. This necessitates a successful transition from pediatric to adult health care. Care for transitioning patients with SCD often falls to primary care providers who may not be fully aware of the many challenges and issues faced by patients and the current management strategies for SCD. In this review, we aim to close the knowledge gap between primary care providers and specialists who treat transitioning patients with SCD. We describe the challenges and issues encountered by these patients, and we propose a biopsychosocial multidisciplinary approach to the management of the identified issues. Examples of this approach, such as transition-focused integrated care models and quality improvement collaboratives, with the potential to improve health outcomes in adulthood are also described.
Well-being outcomes in Bolivia : Accounting for the effects of ethnicity and regional location

This study assesses well-being differences in Bolivia. We specifically investigate whether ethnicity and regional location explain differences in housing quality, material wealth, sanitation, and educational achievement in Bolivia. We use the 1994 and 1998 DHS surveys of 9114 and 12109 cases, respectively, to test the study hypotheses, which predict that indigenous ethnicity and highland location negatively affect well-being. Results show that in both surveys, indigenous households had lower levels of housing quality, material wealth, and sanitation as compared to non-indigenous households. Indigenous heads of household also showed lower levels of education as compared to non-indigenous heads of household. Households located in the highlands showed lower levels of housing quality and sanitation in both 1994 and 1998. Highland location was a significant predictor of material wealth in the 1998 model but not in the 1994 one. Highland location was not a significant predictor of education in either the 1994 or 1998 models. Rural–urban location had the largest influence on well-being.
Effect of pH on acetylcholinesterase Langmuir and Langmuir-Blodgett films studied by surface potential and atomic force microscopy

Abstract Surface potential measurements have been used to determine the dipole interactions of the acetylcholinesterase (AChE) monolayer at the air/aqueous interface. The results show that it is the ionogenic groups of the enzyme that cause significant changes in the surface potential of the monolayer as the pH of the sub-phase is changed. The atomic force microscope (AFM) images of AChE Langmuir–Blodgett (LB) films indicate that at low pH, an unfolding of the enzyme occurs which leads to formation of large domains at the air/aqueous interface rather than an organized AChE monolayer. Furthermore, the AFM images of the AChE LB film prepared at basic pH show that the enzyme forms aggregates.
Perforated Micro- and Nanopores in Free-Standing Polymer Membranes Fabricated by Nanoimprint Lithography and Pressed Self-Perfection Method

This study presents a stable and flexible method for fabricating a free-standing polymer membrane with perforated micro- and nanopores using an imprint lithography combined with a pressed self-perfection method and a sacrificial layer technique. For the fabrication, micropores were initially patterned on a double resist layer: the upper SU-8 resist layer as an active membrane layer and the lower life-off resist used as a sacrificial layer. The membrane with micropores was then pressed with a flat quartz wafer to reduce pore size down to sub-micrometer. Finally, a free-standing SU-8 membrane with perforated micro- and nanopores was successfully lifted-off from the substrate by dissolving the sacrificial layer.Copyright © 2009 by ASME
A comprehensive approach to database management of quantitative structure-activity relationships (QSAR) in chemistry and biology

Many quantitative structure-activity relationships (QSARs) have been published in pure organic chemistry as well as from biological sources since 1935 when Hammett introduced his equation. We have organized a database of about 6,000 QSARs about evenly divided from both sources. We discuss how the database can be searched for different types of QSAR and how this facilitates comparison of new QSARs with published results. >
Bioenergetics and the origin of hominid bipedalism

Compared to most quadrupedal mammals, humans are energetically inefficient when running at high speeds. This fact can be taken to mean that human dipedalism evolved for reasons other than to reduce relative energy cost durding locomotion. Recalculation of the energy expending expended during human walking at normal speeds shows that 1) human bipedalism is at least as efficient as typical mammalian quadrupedalism and 2) human gait is much more efficient than bipedal or quadrupedal locomotion in the chimpanzee. We conclude that bipedalism bestowed an energetic advantage on the Miocene hominoid ancestors of the Hominidae.
Body image and suicidal ideation in adolescents.

Abstract Data from 231 adolescents (mean age = 15.7, SD = 1.39) were collected from a public school setting in the United States. Participants completed several measures, including those assessing depression, hopelessness, past suicidal behavior, body image, and current suicidal ideation. It was hypothesized that depression, hopelessness, past suicidal behavior, and body image (a risk factor seldom examined) would significantly predict current suicidal ideation and that there would be gender differences for body image. Regression analyses indicated that all risk factors including body image were significant predictors of current suicidal ideation for the whole sample. For both males and females, body image offered a unique contribution to the measurement of suicide ideation above and beyond the other risk factors, with body attitudes/feelings being the strongest predictor. Results encourage the inclusion of body image as a variable in risk models for adolescent suicidal ideation, as it likely accounts for additional variance above and beyond traditional risk factors.
Text a librarian: a look from the user perspective

Purpose – The aim of this paper is to provide an in-depth examination of the use and non-use of text reference service among library users, seeking to evaluate the service from library users' perspective and hence enhance the professional understanding of the best practices of text reference service. Design/methodology/approach – A survey study was conducted among library users, examining user demographics, user's texting behavior, user awareness of text reference service, and users' use or non-use of the service. Findings – Findings suggest that the majority of library users have not used the service and their non-use is primarily attributed to their lack of awareness. Users who have used the service report a high degree of satisfaction and appreciate the convenience, ease of use and speediness of the service. Practical implications – The paper helps interested libraries develop an enriched view of texting's affordance as a reference service venue and thus make more informed decisions in successfully imp...
Diagenesis and Geochemistry of Sediments in Marine Environment: ABSTRACT

Diagenetic alterations were induced in sediments in a model representing a shallow-marine shelf by injecting synthetic sea water under partial pressure of carbon dioxide. The sediments from the model were then removed and studied under the petrographic microscope. The study included (1) the interrelation of the chemistry of the interstitial fluid and the mineralogy of sediments, (2) the factors controlling the formation of silica and calcite cements, (3) the processes responsible for transforming sediments into hard rocks, and (4) the sequence of these processes. The precipitation of silica and calcium carbonate as cements in the model sediments was detected under the petrographic microscope and is shown on photomicrographs. The petrographic analyses indicate that during early diagenesis cements formed in intergranular space only. The calcite cement crystallizes as small fibrous crystals around the grains extending into the pore space and subsequently results in rim cement. Silica cement is formed simultaneously both as overgrowths and in optical continuity around sand grains. The silica and calcite precipitated as cements in the model seem to be derived from the interaction of clays and sea water. Geochemical environments for such reactions and environments which enhance the cementation of sediments were interpreted from the studies. End_of_Article - Last_Page 634------------
Quantitative evaluation of rejuvenators to restore embrittlement temperatures in oxidized asphalt mixtures using acoustic emission

Towards developing a method capable to assess the efficiency of rejuvenators to restore embrittlement temperatures of oxidized asphalt binders towards their original, i.e., unaged values, three gyratory compacted specimens were manufactured with mixtures oven-aged for 36 hours at 135 °C. In addition, one gyratory compacted specimen manufactured using a short-term oven-aged mixture for two hours at 155 °C was used for control to simulate aging during plant production. Each of these four gyratory compacted specimens was then cut into two cylindrical specimen 5 cm thick for a total of six 36-hour oven-aged specimens and two short term aging specimens. Two specimens aged for 36 hours and the two short-term specimens were then tested using an acoustic emission approach to obtain base acoustic emission response of short-term and severely-aged specimens. The remaining four specimens oven-aged for 36 hours were then treated by spreading their top surface with rejuvenator in the amount of 10% of the binder by weight. These four specimens were then tested using the same acoustic emission approach after two, four, six, and eight weeks of dwell time. It was observed that the embrittlement temperatures of the short-term aged and severely oven-aged specimens were -25 °C and - 15 °C, respectively. It was also observed that after four weeks of dwell time, the rejuvenator-treated samples had recuperated the original embrittlement temperatures. In addition, it was also observed that the rejuvenator kept acting upon the binder after four weeks of dwell time; at eight weeks of dwell time, the specimens had an embrittlement temperature about one grade cooler than the embrittlement temperature corresponding to the short-term aged specimen.
Reactions of Perfluoroalkyl Iodides with M(C5H5)(CO)(PMe3) [M = Rh, Ir]; Evidence for Direct Fluoroalkylation at a CO Ligand

While reaction of n-C3F7I with CpRh(PMe3)(CO) gives the expected product of oxidative addition, CpRh(PMe3)(nC3F7)(I), the analogous reaction of iso-C3F7I affords a mixture of CpRh(PMe3)(CF(CF3)2)(I) and the perfluoroacyl complex CpRh(PMe3)(COCF(CF3)2)(I). The latter compound is not formed from the former by a migratory insertion reaction. In further contrast, low-temperature reaction of CpIr(CO)(PMe3) with n-C3F7I gives the ionic complex [CpIr(CO)(PMe3)(nC3F7)]+I-, which is inert to thermal substitution; treatment with N-methylmorpholine-N-oxide (NMO) results in CO oxidation and iodide coordination to give CpIr(PMe3)(nC3F7)(I). The same reaction at room temperature affords a mixture of four products, including small amounts of [CpIr(CO)(PMe3)(nC3F7)]+I- and CpIr(PMe3)(nC3F7)(I); the major components are the perfluoroacyl complex CpIr(PMe3)(COnC3F7)(I) and the perfluoroacyl(perfluoroalkyl) complex CpIr(PMe3)(COnC3F7)(nC3F7). Crystallographic structure determinations of all these molecules are reported, and...
Moving to mandatory Medicaid managed care in Ohio: impacts on pregnant women and infants.

This study examined the impact of mandatory HMO enrollment on prenatal care use, smoking, and birth weight for Medicaid-covered pregnant women in Ohio using linked birth certificate and Medicaid data in 10 Ohio counties. They found that mandatory HMO enrollment had positive effects on prenatal care and led to a reduction in maternal smoking but found no effects on birth weight. The authors conclude that with careful implementation and attention to individual differences, outcomes for pregnant women may improve with Medicaid managed care. (Kenney, Genevieve, Anna Sommers, and Lisa Dubay. July 2005. Moving to Mandatory Medicaid Managed Care in Ohio: Impacts for Pregnant Women and Infants. Medical Care 43(7): 683-690.)
Electrical Maintenance Problems in a Corning Glass Works Plant

The Corning Glass Works Plant at Martinsburg, W. Va., is a 330 000-ft3 plant located on 66 acres of land. The principal product is Corning PYROCERAM®cookware.
An ab initio molecular orbital study of the grignard reagents CH3MgCl and [CH3MgCl]2: The Schlenk equilibrium

Ab initio molecular orbital calculations are used to study the modified Schlenk equilibrium: 2RMgCl ↔ (RMgCl)2 ↔ MgR2 + MgCl2 ↔ Mg(Cl2)MgR2 with R=H and CH3. In the absence of any solvents, calculations indicate that the formation of the various possible bridged dimers (RMgCl)2 is substantially exothermic. However, using dimethylether as a model solvent, we show that the formation of the dimer (Me2O)(CH3)Mg(ΜCl2)Mg(CH3)(OMe2) is exothermic only when entropic effects are included.
Thirty-five years in bioelectromagnetics research

For 35 years, I have been involved in various bioelectromagnetics research projects including acute and long-term radiofrequency (RF) bioeffects studies, dosimetry, exposure systems, MRI safety, cancer studies involving hyperthermia and electrochemical treatment, development of RF exposure and measurement standards, and product compliance. My first study demonstrated that effects on isolated nerve and muscle preparations were due to thermal effects of RF exposure. The recording of cochlear microphonics in animals shows the mechanical nature of the microwave auditory effect. In 1992, we published the results of a large-scale lifetime study in which 100 rats were sham-exposed and 100 rats were exposed for 21 h/day for 25 months to a pulsed RF signal. In dosimetry studies, human models were employed as well as many animal species including mice, rats, rabbits, monkeys, and birds of many sizes. Cancer hyperthermia studies demonstrated that knowledge of temperature distribution was crucial for successful treatment. Research on electrochemical treatment of tumors with direct current involved cellular, animal, and clinical studies. Over the past few decades, there has been rather extensive investigation of the public health impact of RF exposure. In my opinion, future research in bioelectromagnetics should place greater emphasis on medical applications. Bioelectromagnetics © 2006 Wiley-Liss, Inc.
Vibrational characterization of carbon monoxide oxidation on the Pt(111) surface

Abstract The surface reaction between coadsorbed carbon monoxide and atomic oxygen has been characterized using high resolution electron energy loss spectroscopy, coupled with temperature programmed reaction spectroscopy on a Pt(111) surface characterized using Auger electron spectroscopy and low energy electron diffraction. Preferential oxidation of bridge bonded CO is not observed despite the fact that bridge bonded CO is adsorbed less vigorously than linearly bound CO. Saturation of the Pt(111) surface with one quarter of a monolayer of atomic oxygen completely suppresses the adsorption of bridge bonded CO. However, substantial coverages of bridge bonded CO can be coadsorbed if the Pt(111) surface is only partially saturated with atomic oxygen. The vibrational data for reaction of coadsorbed CO and atomic oxygen is consistent with a reaction mechanism involving reaction of mobile CO along oxygen island perimeters.
The Rovibrational Intensities of the (4001) ← (0000) Pentad Absorption Bands of12C16O2between 7284 and 7921 cm−1

Abstract Absolute line intensities and Herman–Wallis type intensity parameters of 12 C 16 O 2 are experimentally measured for the first time for the (40 0 1) IV ← (00 0 0) band at 7460 cm −1 and the (40 0 1) I ← (00 0 0) band at 7921 cm −1 . The rotationless band strengths at 296 K are respectively[formula]and[formula]In addition, previous measurements on the (40 0 1) II ← (00 0 0) and (40 0 1) III ← (00 0 0) bands have been reanalyzed to be consistent with definitions of Herman–Wallis parameters currently in use.
Hardware-accelerated components for hybrid computing systems

We present a study on the use of component technology for encapsulating platform-specific hardware-accelerated algorithms on hybrid HPC systems. Our research shows that component technology can have significant benefits from a software engineering point-of-view to increase encapsulation, portability and reduce or eliminate platform dependence for hardware-accelerated algorithms.As a demonstration of this concept, we discuss our experience in designing, implementing and integrating an FPGA-accelerated kernel for Polygraph, an application in computational proteomics.
IC-P3-179: Quantifying metabolic asymmetry in Alzheimer's disease using both MR and PET imaging

been modeled previously and include pool-specific T1 and T2 values (T1,F, T1,S, T2,F, T2,S) and volume fractions (fF, fS) as free parameters, allowing their estimation from multi-flip angle SPGR and SSFP data. For in vivo demonstration, whole-brain data were acquired of 4 healthy volunteers on a 1.5T Siemens Sonata clinical scanner. Imaging parameters were: 22cm2 16cm field of view, 256x160x118 matrix, SPGR: TE/TR 3.1ms/6.5ms, angles 2° through 18° in 2° increments; SSFP: TE/TR 2.3ms/4.6ms, angles 6° though 70° in 8° increments. Results: Images through the T1,F, T1,S, T2,F, T2,S and myelin fraction maps are shown in Fig. 1. Mean values obtained from different brain regions are shown in Fig. 2 and agree well with previous literature reports.
Integrative technique for detection of atmospheric ammonia

Abstract Ambient gaseous ammonia (NH3) in the range 0.5–25 ppb (v/v) is collected by pulling sample air through a tube packed with Chromosorb T ∗ . The ammonia is thermally desorbed by raising the tube temperature to 100°C while flushing the tube with purified air. Transient response of either a chemiluminescence or an opto-acoustic detector is integrated to obtain a signal which is linearly related to the total amount of ammonia collected. The capacity of the collection tubes is such that ammonia loadings are limited to 60 ng and collection times to 40 min; for higher loadings or longer collection times, “breakthrough” occurs and sample is lost. Precision of the procedure is approx. ± 3 ng as characterized by 90% confidence intervals based on five replicate measurements at each of several known loadings.
Geochronology and petrogenesis of MORB from the Juan de Fuca and Gorda ridges by 238U230Th disequilibrium

A highly precise mass spectrometric method of analysis was used to determine238U—234U—230Th—232Th in axial and off-axis basalt glasses from Juan de Fuca (JDF) and Gorda ridges. Initial230Th activity excesses in the axial samples range from 3 to 38%, but generally lie within a narrow range of 12 to 15%. Secondary alteration effects were evaluated usingδ234U and appear to be negligible; hence the230Th excesses are magmatic in origin. Direct dating of MORB was accomplished by measuring the decrease in excess230Th in off-axis samples.238U—230Th ages progressively increase with distance from axis. Uncertainties in age range from 10 to 25 ka for U—Th ages of 50 to 200 ka. The full spreading rate based on U—Th ages for Endeavour segment of JDF is 5.9 ± 1/2 cm/yr, with asymmetry in spreading between the Pacific (4.0 ± 0.6 cm/yr) and JDF (1.9 ± 0.6 cm/yr) plates. For northern Gorda ridge, the half spreading rate for the JDF plate is found to be 3.0 ± 0.4 cm/yr. These rates are in agreement with paleomagnetic spreading rates and topographic constraints. This suggests that assumptions used to determine ages, including constancy of initial 230Th/232Th ratio over time, are generally valid for the areas studied. Samples located near the axis of spreading are typically younger than predicted by these spreading rates, which most likely reflects recent volcanism within a 1–3 km wide zone of crustal accretion. Initial230Th/232Th ratios and230Th activity were also used to examine the recent Th/U evolution and extent of melting of mantle sources beneath these ridges. A negative anomaly in 230Th/232Th for Axial seamount lavas provides the first geochemical evidence of a mantle plume source for Axial seamount and the Cobb-Eickelberg seamount chain and indicates recent depletion of other JDF segment sources. Large230Th activity excesses for lavas from northern Gorda ridge and Endeavour segment indicate formation from a lower degree of partial melting than other segments. An inverse correlation between230Th excess and 230Th/232Th for each ridge indicates that these lower degree melts formed from slightly less depleted sources than higher degree melts. Uniformity in230Th excess for other segments suggests similarity in processes of melt formation and mixing beneath most of the JDF-Gorda ridge area. The average initial230Th/232Th activity ratio of 1.31 for the JDF-Gorda ridge area is in agreement with the predicted value of 1.32 from the Th—Sr isotope mantle array.
High temperature erosion of tantalum carbide composites

Abstract Selected compositions of tantalum carbide composites containing excess free carbon and tungsten-rhenium were tested for erosion resistance at 1800 °C and room temperature. Specimens were fabricated at 2150 °C using hot pressing techniques. Tantalum carbide exhibited superior erosion resistance at both temperatures and displayed evidence of cutting erosion only. Graphite and hafnia-tungsten composites exhibited less erosion resistance at both temperatures and displayed evidence of both cutting and deformation erosion.
Sudden infant death syndrome among extremely preterm infants: United States 1997-1999

BACKGROUND: Preterm infants have been reported to be at higher risk than term infants for sudden infant death syndrome (SIDS). Reasons for this higher risk are not clear. OBJECTIVE: The objective of this study was to analyze medical and demographic characteristics among infants 24 to 32 weeks gestation to identify characteristics more prevalent among infants dying of SIDS in the postneonatal period than among infants of similar gestation who survived or who died of other causes in the postneonatal period. DESIGN/METHODS: United States linked birth and death certificate period data for 1997 to 1999 were used for this analysis. The population used was limited to infants 24 to 32 weeks gestation weighing 500 to 2500 g. SIDS deaths were limited to the postneonatal period and compared to survivors and infants dying in the postneonatal period of other causes. RESULTS: There were 469 postneonatal SIDS deaths with complete data (rate=2.2/1000 live births surviving ≥28 days); 3950 other postneonatal deaths (rate=18.7/1000) and 206,640 survivors. Compared with survivors, infants dying of SIDS were more likely to be born to mothers with 3 previous pregnancies (OR=2.6, 95% CI=1.9, 3.5). Compared with infants dying in the postneonatal period of other causes, these same demographic factors continued to be significant risk factors for SIDS. There were no medical risk factors such as breech presentation, abruptio placenta, Apgar score 30 minutes after birth, for which infants dying of SIDS were at greater risk than survivors or infants dying of other causes. CONCLUSIONS: Risk factors for SIDS among infants 24 to 32 weeks gestation appear to be more associated with sociodemographic characteristics than medical characteristics. This suggests that for the immediate future, the risk for SIDS among very preterm infants will be best addressed through further modification of the environment and parent behavior.
Transverse anatomic landmarks for the A1 pulley of the thumb.

Background Triggering of the thumb is a common entity resulting in pain and disability. Operative management requires accurate knowledge of the pulley system for proper release of the A1 pulley. The purpose of this study was to predict the location of the A1 pulley with surface anatomic landmarks while avoiding injury to the neurovascular bundles and the critical oblique pulley.
Transmitter release from frog motor nerve terminals depends on motor unit size.

It has been postulated that the success with which a motor nerve terminal competes for synaptic connections1,2 or the ability of an axon to maintain sprouts3 may depend on the support each terminal receives from its soma, presumably in the form of some substance(s) synthesized there. The support received by each terminal may in turn depend on the total number of terminals maintained by that soma, namely, motor unit size. We show here that when motor unit size is experimentally decreased, transmitter release from the terminals is markedly enhanced. This is consistent with the view that the extent of support from the soma may also influence the effectiveness of synaptic transmission.
Drug discrimination based on the competitive N-methyl-d-aspartate antagonist, NPC 12626

The discriminative stimulus effects of the N-methyl-d-aspartate (NMDA) antagonists 3-([+/-]-2-carboxypiperazin-4-yl)propyl-1-phosphonic acid (CPP) and phencyclidine were assessed in a drug discrimination based on the competitive NMDA antagonist 2-amino-4,5-(1,2-cyclohexyl)-7-phosphonoheptanoic acid (NPC 12626). Adult male Sprague-Dawley rats were trained to discriminate NPC 12626 from saline using a standard two-lever fixed ratio 32 schedule of food reinforcement. NPC 12626 dose-dependently substituted for the training dose (20 mg/kg IP) with an ED50 of 9.5 mg/kg. The competitive NMDA antagonist CPP completely substituted for NPC 12626 (ED50=1.4 mg/kg IP). The non-competitive NMDA antagonist phencyclidine, as well as pentobarbital and NMDA, failed to substitute completely for NPC 12626, even at doses of these drugs that reduced response rates. These data indicate that the discriminative stimulus properties of NPC 12626 are selective and shared by CPP but not by phencyclidine, pentobarbital or NMDA. The emerging evidence for differences in the discriminative stimulus effects of competitive NMDA antagonists and phencyclidine suggests that competitive antagonists such as NPC 12626 and CPP may not have phencyclidine-like abuse liability.
Interactive Chromatin Folding, Nucleosome (Mis)Positioning and Chromatin Structure

In the absence of the myriad influences that exist in a cell nucleus, the positioning and stability of nucleosomes on a short segment of DNA are governed by the material properties of the DNA. In the simplest view sequences of DNA that are intrinsically flexible or that are intrinsically curved lead to nucleosome positioning. Nucleosome positioning is thus an intra-nucleosome based effect. In vivo or for sequences of DNA that support multiple nucleosomes, nucleosome-nucleosome interactions and extra-nucleosomal (e.g. chromatin remodeling factors) interactions must also be considered.In case of intra-nucleosomal based positioning, DNA material defects (defined as variations in flexibility or conformation) are hidden because the histones force the DNA to assume a well defined super helical fold. Except for specifically constructed sequences of DNA, chromatin structures determined by intra-nucleosome interactions are irregular because the nucleosome positions will be irregular.In case inter- or extra- nucleosomal interactions determine the nucleosome positions some DNA defects will be exposed in linker DNA regions. Exposure of the defects impacts the global structure of chromatin, e.g. a bent linker yields bent chromatin.We propose that chromatin structure is biased toward one method of positioning or the other depending on environmental conditions. Thus for a given sequence of DNA both irregular and regular structures can be obtained. Our Interactive Chromatin Modeling Web Server http://www.latech.edu/∼bishop captures these ideas. Here we present a case study of how ICM Web can be used to study the folding of the mouse mammary tumor virus promoter complex(MMTV). ICM properly predicts the locations of six positioned nucleosomes in the MMTV and shows how mispositioning reveals sequence specific material defects that bend chromatin.
Rotational behavior in gerbils following unilateral common carotid artery ligation.

Unilateral cerebral infarctions are produced in 30–50% of all gerbils subjected to ipsilateral ligation of a common carotid artery. It has previously been shown that this infarction is associated with a major depletion of ipsilateral brain dopamine. The present studies characterize the spontaneous and drug-induced rotational behavior manifested by these animals and attempt to relate it to the functional activity of dopaminergic synapses. The tendency of animals to turn towards the side of the lesion 2–3 hours after surgery was found to correlate highly with the unilateral dopamine depletion observed after 24 hours. Two patterns of rotational responses were observed among animals showing symptoms that were treated with d-amphetamine or apomorphine; these could be correlated with mortality 24 hours after surgery.
High-fidelity replication of diffractive optics using radiation-curable liquid photopolymers

A low-cost process for replicating diffractive optics has been demonstrated using radiation-curable liquid photopolymers on plastic substrates. Two- and eight-level f/10 quartz master elements were embossed into liquid photopolymers and subsequently cured under pressure using high-intensity ultraviolet (UV) radiation. The quartz master is easily separated from the hardened replica and immediately available for reuse. High-fidelity replicas with the same surface polarity as the original master can be made from nickel electroforms. For obtaining good optical image quality replicas, quartz masters were found to be significantly better than nickel masters. High- fidelity replication of surface relief structures was verified using an optical microscope, a Scanning Electron Microscope (SEM), and a 2-D scanning profilometer. Nearly theoretical diffraction efficiency (39.4% versus 40.5%) was achieved with the two-level f/10 replica. Optical image quality was degraded by substrate warping and submicron surface roughness as evidenced by increasing distortion of the blur spot over larger replica diameters. Less than 10% shrinkage was measured in the vertical dimension with no shrinkage measured in the horizontal plane. Although optical image quality applications are limited, the process is suitable for applications such as polarizers and microlens arrays.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Research and design guidelines for the construction of fiber-reinforced polymer reinforced concrete structures under fire exposure: A brief review

This article presents the state-of-the-art literature review for the behavior of fiber-reinforced polymer and performance of fiber-reinforced polymer reinforced concrete structures exposed to high temperatures. The article is organized into six parts. They are thermo-mechanical properties of fiber-reinforced polymer composites, bond characteristics of fiber-reinforced polymers at high temperatures, fire reaction properties of fiber-reinforced polymer composites, fire protection methods, performance of fiber-reinforced polymer reinforced concrete structures under fire conditions, and design codes. The design codes presented herein are that of American Concrete Institute and the Canada Standards Association. Sections pertaining to fiber-reinforced polymer fire design in these codes are discussed, including the future developments for enhancing the performance of fiber-reinforced polymer reinforced concrete structures under elevated temperatures.
Rhythmic beach cusp formation: A conceptual synthesis

Abstract Observations of a sandy beach at Santa Barbara, California, during February 1980 documented the sequence of beach cusp formation, replacement by a second set of rhythmic cusps obliterating the first set, and finally complete planation of all rhythmic cusps during a major storm. Although neither cusp-building event was observed during its initiation, the wave and tide conditions during formation were well documented by in-situ instrumentation. Based on these field observations and those by other investigators, a coherent conceptual theory of beach cusp formation is proposed, including formative, maintenance and destructive phases. This theory proposes rhythmic cusp formation during relative stillstands of sea level of sufficient duration to permit initial perturbation of beach geometry; regularly spaced cusps acquire their initial spacing from subharmonic edge waves (such that spacing derives from the incident wave period); growth of the initial perturbation continues until cusps reach a limiting value, not necessarily with continuation of edge wave motion; the cusp spacing persists until a change in wave conditions either destroys the cusps, or establishes a radically different spacing; and finally, that large storms will destroy the rhythmic cusp field, leaving either a planar beach or a beach with arhythmic cusp-like features.
Astrocyte RNA in relation to neuronal RNA depletion in Alzheimer's disease.

A new double-staining procedure, in which the techniques of immunocytochemistry of glial fibrillary acidic protein (GFAP) and quantitative microdensitometry of azure B-RNA were combined, was used to study nucleic acid alterations in fibrous astrocytes in Alzheimer's disease (AD). RNA contents of GFAP-positive cells of the hippocampal endplate (Rose's H3-H5 fields) and the dentate gyrus molecular layer were determined in ten autopsy-proven AD patients (ages 51–88) and ten age-matched, non-demented control. In addition, RNA contents of pyramidal neurons of the endplate were examined. While there were no differences in RNA contents of astrocytes of either region between AD patients and controls, neuronal RNA was markedly depleted. These data suggest that astrocytes maintain protein synthetic capabilities in AD and that RNA loss is limited to the neuronal compartment.
Multivariable harmonic balance for central pattern generators

The central pattern generator (CPG) is a nonlinear oscillator formed by a group of neurons, providing a fundamental control mechanism underlying rhythmic movements in animal locomotion. We consider a class of CPGs modeled by a set of interconnected identical neurons. Based on the idea of multivariable harmonic balance, we show how the oscillation profile is related to the connectivity matrix that specifies the architecture and strengths of the interconnections. Specifically, the frequency, amplitudes, and phases are essentially encoded in terms of a pair of eigenvalue and eigenvector. This basic principle is used to estimate the oscillation profile of a given CPG model. Moreover, a systematic method is proposed for designing a CPG-based nonlinear oscillator that achieves a prescribed oscillation profile.